fs/btrfs/extent-tree.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/writeback.h>
  21 #include <linux/blkdev.h>
  22 #include <linux/sort.h>
  23 #include <linux/rcupdate.h>
  24 #include <linux/kthread.h>
  25 #include <linux/slab.h>
  26 #include <linux/ratelimit.h>
  27 #include <linux/percpu_counter.h>
  28 #include "hash.h"
  29 #include "tree-log.h"
  30 #include "disk-io.h"
  31 #include "print-tree.h"
  32 #include "volumes.h"
  33 #include "raid56.h"
  34 #include "locking.h"
  35 #include "free-space-cache.h"
  36 #include "free-space-tree.h"
  37 #include "math.h"
  38 #include "sysfs.h"
  39 #include "qgroup.h"
  40
  41 #undef SCRAMBLE_DELAYED_REFS
  42
  43 /*
  44  * control flags for do_chunk_alloc's force field
  45  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  46  * if we really need one.
  47  *
  48  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  49  * if we have very few chunks already allocated.  This is
  50  * used as part of the clustering code to help make sure
  51  * we have a good pool of storage to cluster in, without
  52  * filling the FS with empty chunks
  53  *
  54  * CHUNK_ALLOC_FORCE means it must try to allocate one
  55  *
  56  */
  57 enum {
  58         CHUNK_ALLOC_NO_FORCE = 0,
  59         CHUNK_ALLOC_LIMITED = 1,
  60         CHUNK_ALLOC_FORCE = 2,
  61 };
  62
  63 /*
  64  * Control how reservations are dealt with.
  65  *
  66  * RESERVE_FREE - freeing a reservation.
  67  * RESERVE_ALLOC - allocating space and we need to update bytes_may_use for
  68  *   ENOSPC accounting
  69  * RESERVE_ALLOC_NO_ACCOUNT - allocating space and we should not update
  70  *   bytes_may_use as the ENOSPC accounting is done elsewhere
  71  */
  72 enum {
  73         RESERVE_FREE = 0,
  74         RESERVE_ALLOC = 1,
  75         RESERVE_ALLOC_NO_ACCOUNT = 2,
  76 };
  77
  78 static int update_block_group(struct btrfs_trans_handle *trans,
  79                               struct btrfs_root *root, u64 bytenr,
  80                               u64 num_bytes, int alloc);
  81 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  82                                 struct btrfs_root *root,
  83                                 struct btrfs_delayed_ref_node *node, u64 parent,
  84                                 u64 root_objectid, u64 owner_objectid,
  85                                 u64 owner_offset, int refs_to_drop,
  86                                 struct btrfs_delayed_extent_op *extra_op);
  87 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  88                                     struct extent_buffer *leaf,
  89                                     struct btrfs_extent_item *ei);
  90 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  91                                       struct btrfs_root *root,
  92                                       u64 parent, u64 root_objectid,
  93                                       u64 flags, u64 owner, u64 offset,
  94                                       struct btrfs_key *ins, int ref_mod);
  95 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  96                                      struct btrfs_root *root,
  97                                      u64 parent, u64 root_objectid,
  98                                      u64 flags, struct btrfs_disk_key *key,
  99                                      int level, struct btrfs_key *ins);
 100 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
 101                           struct btrfs_root *extent_root, u64 flags,
 102                           int force);
 103 static int find_next_key(struct btrfs_path *path, int level,
 104                          struct btrfs_key *key);
 105 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
 106                             int dump_block_groups);
 107 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
 108                                        u64 num_bytes, int reserve,
 109                                        int delalloc);
 110 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
 111                                u64 num_bytes);
 112 int btrfs_pin_extent(struct btrfs_root *root,
 113                      u64 bytenr, u64 num_bytes, int reserved);
 114
 115 static noinline int
 116 block_group_cache_done(struct btrfs_block_group_cache *cache)
 117 {
 118         smp_mb();
 119         return cache->cached == BTRFS_CACHE_FINISHED ||
 120                 cache->cached == BTRFS_CACHE_ERROR;
 121 }
 122
 123 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 124 {
 125         return (cache->flags & bits) == bits;
 126 }
 127
 128 void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 129 {
 130         atomic_inc(&cache->count);
 131 }
 132
 133 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 134 {
 135         if (atomic_dec_and_test(&cache->count)) {
 136                 WARN_ON(cache->pinned > 0);
 137                 WARN_ON(cache->reserved > 0);
 138                 kfree(cache->free_space_ctl);
 139                 kfree(cache);
 140         }
 141 }
 142
 143 /*
 144  * this adds the block group to the fs_info rb tree for the block group
 145  * cache
 146  */
 147 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 148                                 struct btrfs_block_group_cache *block_group)
 149 {
 150         struct rb_node **p;
 151         struct rb_node *parent = NULL;
 152         struct btrfs_block_group_cache *cache;
 153
 154         spin_lock(&info->block_group_cache_lock);
 155         p = &info->block_group_cache_tree.rb_node;
 156
 157         while (*p) {
 158                 parent = *p;
 159                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 160                                  cache_node);
 161                 if (block_group->key.objectid < cache->key.objectid) {
 162                         p = &(*p)->rb_left;
 163                 } else if (block_group->key.objectid > cache->key.objectid) {
 164                         p = &(*p)->rb_right;
 165                 } else {
 166                         spin_unlock(&info->block_group_cache_lock);
 167                         return -EEXIST;
 168                 }
 169         }
 170
 171         rb_link_node(&block_group->cache_node, parent, p);
 172         rb_insert_color(&block_group->cache_node,
 173                         &info->block_group_cache_tree);
 174
 175         if (info->first_logical_byte > block_group->key.objectid)
 176                 info->first_logical_byte = block_group->key.objectid;
 177
 178         spin_unlock(&info->block_group_cache_lock);
 179
 180         return 0;
 181 }
 182
 183 /*
 184  * This will return the block group at or after bytenr if contains is 0, else
 185  * it will return the block group that contains the bytenr
 186  */
 187 static struct btrfs_block_group_cache *
 188 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 189                               int contains)
 190 {
 191         struct btrfs_block_group_cache *cache, *ret = NULL;
 192         struct rb_node *n;
 193         u64 end, start;
 194
 195         spin_lock(&info->block_group_cache_lock);
 196         n = info->block_group_cache_tree.rb_node;
 197
 198         while (n) {
 199                 cache = rb_entry(n, struct btrfs_block_group_cache,
 200                                  cache_node);
 201                 end = cache->key.objectid + cache->key.offset - 1;
 202                 start = cache->key.objectid;
 203
 204                 if (bytenr < start) {
 205                         if (!contains && (!ret || start < ret->key.objectid))
 206                                 ret = cache;
 207                         n = n->rb_left;
 208                 } else if (bytenr > start) {
 209                         if (contains && bytenr <= end) {
 210                                 ret = cache;
 211                                 break;
 212                         }
 213                         n = n->rb_right;
 214                 } else {
 215                         ret = cache;
 216                         break;
 217                 }
 218         }
 219         if (ret) {
 220                 btrfs_get_block_group(ret);
 221                 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
 222                         info->first_logical_byte = ret->key.objectid;
 223         }
 224         spin_unlock(&info->block_group_cache_lock);
 225
 226         return ret;
 227 }
 228
 229 static int add_excluded_extent(struct btrfs_root *root,
 230                                u64 start, u64 num_bytes)
 231 {
 232         u64 end = start + num_bytes - 1;
 233         set_extent_bits(&root->fs_info->freed_extents[0],
 234                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 235         set_extent_bits(&root->fs_info->freed_extents[1],
 236                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 237         return 0;
 238 }
 239
 240 static void free_excluded_extents(struct btrfs_root *root,
 241                                   struct btrfs_block_group_cache *cache)
 242 {
 243         u64 start, end;
 244
 245         start = cache->key.objectid;
 246         end = start + cache->key.offset - 1;
 247
 248         clear_extent_bits(&root->fs_info->freed_extents[0],
 249                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 250         clear_extent_bits(&root->fs_info->freed_extents[1],
 251                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 252 }
 253
 254 static int exclude_super_stripes(struct btrfs_root *root,
 255                                  struct btrfs_block_group_cache *cache)
 256 {
 257         u64 bytenr;
 258         u64 *logical;
 259         int stripe_len;
 260         int i, nr, ret;
 261
 262         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 263                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 264                 cache->bytes_super += stripe_len;
 265                 ret = add_excluded_extent(root, cache->key.objectid,
 266                                           stripe_len);
 267                 if (ret)
 268                         return ret;
 269         }
 270
 271         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 272                 bytenr = btrfs_sb_offset(i);
 273                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 274                                        cache->key.objectid, bytenr,
 275                                        0, &logical, &nr, &stripe_len);
 276                 if (ret)
 277                         return ret;
 278
 279                 while (nr--) {
 280                         u64 start, len;
 281
 282                         if (logical[nr] > cache->key.objectid +
 283                             cache->key.offset)
 284                                 continue;
 285
 286                         if (logical[nr] + stripe_len <= cache->key.objectid)
 287                                 continue;
 288
 289                         start = logical[nr];
 290                         if (start < cache->key.objectid) {
 291                                 start = cache->key.objectid;
 292                                 len = (logical[nr] + stripe_len) - start;
 293                         } else {
 294                                 len = min_t(u64, stripe_len,
 295                                             cache->key.objectid +
 296                                             cache->key.offset - start);
 297                         }
 298
 299                         cache->bytes_super += len;
 300                         ret = add_excluded_extent(root, start, len);
 301                         if (ret) {
 302                                 kfree(logical);
 303                                 return ret;
 304                         }
 305                 }
 306
 307                 kfree(logical);
 308         }
 309         return 0;
 310 }
 311
 312 static struct btrfs_caching_control *
 313 get_caching_control(struct btrfs_block_group_cache *cache)
 314 {
 315         struct btrfs_caching_control *ctl;
 316
 317         spin_lock(&cache->lock);
 318         if (!cache->caching_ctl) {
 319                 spin_unlock(&cache->lock);
 320                 return NULL;
 321         }
 322
 323         ctl = cache->caching_ctl;
 324         atomic_inc(&ctl->count);
 325         spin_unlock(&cache->lock);
 326         return ctl;
 327 }
 328
 329 static void put_caching_control(struct btrfs_caching_control *ctl)
 330 {
 331         if (atomic_dec_and_test(&ctl->count))
 332                 kfree(ctl);
 333 }
 334
 335 #ifdef CONFIG_BTRFS_DEBUG
 336 static void fragment_free_space(struct btrfs_root *root,
 337                                 struct btrfs_block_group_cache *block_group)
 338 {
 339         u64 start = block_group->key.objectid;
 340         u64 len = block_group->key.offset;
 341         u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ?
 342                 root->nodesize : root->sectorsize;
 343         u64 step = chunk << 1;
 344
 345         while (len > chunk) {
 346                 btrfs_remove_free_space(block_group, start, chunk);
 347                 start += step;
 348                 if (len < step)
 349                         len = 0;
 350                 else
 351                         len -= step;
 352         }
 353 }
 354 #endif
 355
 356 /*
 357  * this is only called by cache_block_group, since we could have freed extents
 358  * we need to check the pinned_extents for any extents that can't be used yet
 359  * since their free space will be released as soon as the transaction commits.
 360  */
 361 u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 362                        struct btrfs_fs_info *info, u64 start, u64 end)
 363 {
 364         u64 extent_start, extent_end, size, total_added = 0;
 365         int ret;
 366
 367         while (start < end) {
 368                 ret = find_first_extent_bit(info->pinned_extents, start,
 369                                             &extent_start, &extent_end,
 370                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 371                                             NULL);
 372                 if (ret)
 373                         break;
 374
 375                 if (extent_start <= start) {
 376                         start = extent_end + 1;
 377                 } else if (extent_start > start && extent_start < end) {
 378                         size = extent_start - start;
 379                         total_added += size;
 380                         ret = btrfs_add_free_space(block_group, start,
 381                                                    size);
 382                         BUG_ON(ret); /* -ENOMEM or logic error */
 383                         start = extent_end + 1;
 384                 } else {
 385                         break;
 386                 }
 387         }
 388
 389         if (start < end) {
 390                 size = end - start;
 391                 total_added += size;
 392                 ret = btrfs_add_free_space(block_group, start, size);
 393                 BUG_ON(ret); /* -ENOMEM or logic error */
 394         }
 395
 396         return total_added;
 397 }
 398
 399 static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl)
 400 {
 401         struct btrfs_block_group_cache *block_group;
 402         struct btrfs_fs_info *fs_info;
 403         struct btrfs_root *extent_root;
 404         struct btrfs_path *path;
 405         struct extent_buffer *leaf;
 406         struct btrfs_key key;
 407         u64 total_found = 0;
 408         u64 last = 0;
 409         u32 nritems;
 410         int ret;
 411         bool wakeup = true;
 412
 413         block_group = caching_ctl->block_group;
 414         fs_info = block_group->fs_info;
 415         extent_root = fs_info->extent_root;
 416
 417         path = btrfs_alloc_path();
 418         if (!path)
 419                 return -ENOMEM;
 420
 421         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 422
 423 #ifdef CONFIG_BTRFS_DEBUG
 424         /*
 425          * If we're fragmenting we don't want to make anybody think we can
 426          * allocate from this block group until we've had a chance to fragment
 427          * the free space.
 428          */
 429         if (btrfs_should_fragment_free_space(extent_root, block_group))
 430                 wakeup = false;
 431 #endif
 432         /*
 433          * We don't want to deadlock with somebody trying to allocate a new
 434          * extent for the extent root while also trying to search the extent
 435          * root to add free space.  So we skip locking and search the commit
 436          * root, since its read-only
 437          */
 438         path->skip_locking = 1;
 439         path->search_commit_root = 1;
 440         path->reada = READA_FORWARD;
 441
 442         key.objectid = last;
 443         key.offset = 0;
 444         key.type = BTRFS_EXTENT_ITEM_KEY;
 445
 446 next:
 447         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 448         if (ret < 0)
 449                 goto out;
 450
 451         leaf = path->nodes[0];
 452         nritems = btrfs_header_nritems(leaf);
 453
 454         while (1) {
 455                 if (btrfs_fs_closing(fs_info) > 1) {
 456                         last = (u64)-1;
 457                         break;
 458                 }
 459
 460                 if (path->slots[0] < nritems) {
 461                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 462                 } else {
 463                         ret = find_next_key(path, 0, &key);
 464                         if (ret)
 465                                 break;
 466
 467                         if (need_resched() ||
 468                             rwsem_is_contended(&fs_info->commit_root_sem)) {
 469                                 if (wakeup)
 470                                         caching_ctl->progress = last;
 471                                 btrfs_release_path(path);
 472                                 up_read(&fs_info->commit_root_sem);
 473                                 mutex_unlock(&caching_ctl->mutex);
 474                                 cond_resched();
 475                                 mutex_lock(&caching_ctl->mutex);
 476                                 down_read(&fs_info->commit_root_sem);
 477                                 goto next;
 478                         }
 479
 480                         ret = btrfs_next_leaf(extent_root, path);
 481                         if (ret < 0)
 482                                 goto out;
 483                         if (ret)
 484                                 break;
 485                         leaf = path->nodes[0];
 486                         nritems = btrfs_header_nritems(leaf);
 487                         continue;
 488                 }
 489
 490                 if (key.objectid < last) {
 491                         key.objectid = last;
 492                         key.offset = 0;
 493                         key.type = BTRFS_EXTENT_ITEM_KEY;
 494
 495                         if (wakeup)
 496                                 caching_ctl->progress = last;
 497                         btrfs_release_path(path);
 498                         goto next;
 499                 }
 500
 501                 if (key.objectid < block_group->key.objectid) {
 502                         path->slots[0]++;
 503                         continue;
 504                 }
 505
 506                 if (key.objectid >= block_group->key.objectid +
 507                     block_group->key.offset)
 508                         break;
 509
 510                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 511                     key.type == BTRFS_METADATA_ITEM_KEY) {
 512                         total_found += add_new_free_space(block_group,
 513                                                           fs_info, last,
 514                                                           key.objectid);
 515                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 516                                 last = key.objectid +
 517                                         fs_info->tree_root->nodesize;
 518                         else
 519                                 last = key.objectid + key.offset;
 520
 521                         if (total_found > CACHING_CTL_WAKE_UP) {
 522                                 total_found = 0;
 523                                 if (wakeup)
 524                                         wake_up(&caching_ctl->wait);
 525                         }
 526                 }
 527                 path->slots[0]++;
 528         }
 529         ret = 0;
 530
 531         total_found += add_new_free_space(block_group, fs_info, last,
 532                                           block_group->key.objectid +
 533                                           block_group->key.offset);
 534         caching_ctl->progress = (u64)-1;
 535
 536 out:
 537         btrfs_free_path(path);
 538         return ret;
 539 }
 540
 541 static noinline void caching_thread(struct btrfs_work *work)
 542 {
 543         struct btrfs_block_group_cache *block_group;
 544         struct btrfs_fs_info *fs_info;
 545         struct btrfs_caching_control *caching_ctl;
 546         struct btrfs_root *extent_root;
 547         int ret;
 548
 549         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 550         block_group = caching_ctl->block_group;
 551         fs_info = block_group->fs_info;
 552         extent_root = fs_info->extent_root;
 553
 554         mutex_lock(&caching_ctl->mutex);
 555         down_read(&fs_info->commit_root_sem);
 556
 557         if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
 558                 ret = load_free_space_tree(caching_ctl);
 559         else
 560                 ret = load_extent_tree_free(caching_ctl);
 561
 562         spin_lock(&block_group->lock);
 563         block_group->caching_ctl = NULL;
 564         block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED;
 565         spin_unlock(&block_group->lock);
 566
 567 #ifdef CONFIG_BTRFS_DEBUG
 568         if (btrfs_should_fragment_free_space(extent_root, block_group)) {
 569                 u64 bytes_used;
 570
 571                 spin_lock(&block_group->space_info->lock);
 572                 spin_lock(&block_group->lock);
 573                 bytes_used = block_group->key.offset -
 574                         btrfs_block_group_used(&block_group->item);
 575                 block_group->space_info->bytes_used += bytes_used >> 1;
 576                 spin_unlock(&block_group->lock);
 577                 spin_unlock(&block_group->space_info->lock);
 578                 fragment_free_space(extent_root, block_group);
 579         }
 580 #endif
 581
 582         caching_ctl->progress = (u64)-1;
 583
 584         up_read(&fs_info->commit_root_sem);
 585         free_excluded_extents(fs_info->extent_root, block_group);
 586         mutex_unlock(&caching_ctl->mutex);
 587
 588         wake_up(&caching_ctl->wait);
 589
 590         put_caching_control(caching_ctl);
 591         btrfs_put_block_group(block_group);
 592 }
 593
 594 static int cache_block_group(struct btrfs_block_group_cache *cache,
 595                              int load_cache_only)
 596 {
 597         DEFINE_WAIT(wait);
 598         struct btrfs_fs_info *fs_info = cache->fs_info;
 599         struct btrfs_caching_control *caching_ctl;
 600         int ret = 0;
 601
 602         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 603         if (!caching_ctl)
 604                 return -ENOMEM;
 605
 606         INIT_LIST_HEAD(&caching_ctl->list);
 607         mutex_init(&caching_ctl->mutex);
 608         init_waitqueue_head(&caching_ctl->wait);
 609         caching_ctl->block_group = cache;
 610         caching_ctl->progress = cache->key.objectid;
 611         atomic_set(&caching_ctl->count, 1);
 612         btrfs_init_work(&caching_ctl->work, btrfs_cache_helper,
 613                         caching_thread, NULL, NULL);
 614
 615         spin_lock(&cache->lock);
 616         /*
 617          * This should be a rare occasion, but this could happen I think in the
 618          * case where one thread starts to load the space cache info, and then
 619          * some other thread starts a transaction commit which tries to do an
 620          * allocation while the other thread is still loading the space cache
 621          * info.  The previous loop should have kept us from choosing this block
 622          * group, but if we've moved to the state where we will wait on caching
 623          * block groups we need to first check if we're doing a fast load here,
 624          * so we can wait for it to finish, otherwise we could end up allocating
 625          * from a block group who's cache gets evicted for one reason or
 626          * another.
 627          */
 628         while (cache->cached == BTRFS_CACHE_FAST) {
 629                 struct btrfs_caching_control *ctl;
 630
 631                 ctl = cache->caching_ctl;
 632                 atomic_inc(&ctl->count);
 633                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 634                 spin_unlock(&cache->lock);
 635
 636                 schedule();
 637
 638                 finish_wait(&ctl->wait, &wait);
 639                 put_caching_control(ctl);
 640                 spin_lock(&cache->lock);
 641         }
 642
 643         if (cache->cached != BTRFS_CACHE_NO) {
 644                 spin_unlock(&cache->lock);
 645                 kfree(caching_ctl);
 646                 return 0;
 647         }
 648         WARN_ON(cache->caching_ctl);
 649         cache->caching_ctl = caching_ctl;
 650         cache->cached = BTRFS_CACHE_FAST;
 651         spin_unlock(&cache->lock);
 652
 653         if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
 654                 mutex_lock(&caching_ctl->mutex);
 655                 ret = load_free_space_cache(fs_info, cache);
 656
 657                 spin_lock(&cache->lock);
 658                 if (ret == 1) {
 659                         cache->caching_ctl = NULL;
 660                         cache->cached = BTRFS_CACHE_FINISHED;
 661                         cache->last_byte_to_unpin = (u64)-1;
 662                         caching_ctl->progress = (u64)-1;
 663                 } else {
 664                         if (load_cache_only) {
 665                                 cache->caching_ctl = NULL;
 666                                 cache->cached = BTRFS_CACHE_NO;
 667                         } else {
 668                                 cache->cached = BTRFS_CACHE_STARTED;
 669                                 cache->has_caching_ctl = 1;
 670                         }
 671                 }
 672                 spin_unlock(&cache->lock);
 673 #ifdef CONFIG_BTRFS_DEBUG
 674                 if (ret == 1 &&
 675                     btrfs_should_fragment_free_space(fs_info->extent_root,
 676                                                      cache)) {
 677                         u64 bytes_used;
 678
 679                         spin_lock(&cache->space_info->lock);
 680                         spin_lock(&cache->lock);
 681                         bytes_used = cache->key.offset -
 682                                 btrfs_block_group_used(&cache->item);
 683                         cache->space_info->bytes_used += bytes_used >> 1;
 684                         spin_unlock(&cache->lock);
 685                         spin_unlock(&cache->space_info->lock);
 686                         fragment_free_space(fs_info->extent_root, cache);
 687                 }
 688 #endif
 689                 mutex_unlock(&caching_ctl->mutex);
 690
 691                 wake_up(&caching_ctl->wait);
 692                 if (ret == 1) {
 693                         put_caching_control(caching_ctl);
 694                         free_excluded_extents(fs_info->extent_root, cache);
 695                         return 0;
 696                 }
 697         } else {
 698                 /*
 699                  * We're either using the free space tree or no caching at all.
 700                  * Set cached to the appropriate value and wakeup any waiters.
 701                  */
 702                 spin_lock(&cache->lock);
 703                 if (load_cache_only) {
 704                         cache->caching_ctl = NULL;
 705                         cache->cached = BTRFS_CACHE_NO;
 706                 } else {
 707                         cache->cached = BTRFS_CACHE_STARTED;
 708                         cache->has_caching_ctl = 1;
 709                 }
 710                 spin_unlock(&cache->lock);
 711                 wake_up(&caching_ctl->wait);
 712         }
 713
 714         if (load_cache_only) {
 715                 put_caching_control(caching_ctl);
 716                 return 0;
 717         }
 718
 719         down_write(&fs_info->commit_root_sem);
 720         atomic_inc(&caching_ctl->count);
 721         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 722         up_write(&fs_info->commit_root_sem);
 723
 724         btrfs_get_block_group(cache);
 725
 726         btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
 727
 728         return ret;
 729 }
 730
 731 /*
 732  * return the block group that starts at or after bytenr
 733  */
 734 static struct btrfs_block_group_cache *
 735 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 736 {
 737         struct btrfs_block_group_cache *cache;
 738
 739         cache = block_group_cache_tree_search(info, bytenr, 0);
 740
 741         return cache;
 742 }
 743
 744 /*
 745  * return the block group that contains the given bytenr
 746  */
 747 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 748                                                  struct btrfs_fs_info *info,
 749                                                  u64 bytenr)
 750 {
 751         struct btrfs_block_group_cache *cache;
 752
 753         cache = block_group_cache_tree_search(info, bytenr, 1);
 754
 755         return cache;
 756 }
 757
 758 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 759                                                   u64 flags)
 760 {
 761         struct list_head *head = &info->space_info;
 762         struct btrfs_space_info *found;
 763
 764         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 765
 766         rcu_read_lock();
 767         list_for_each_entry_rcu(found, head, list) {
 768                 if (found->flags & flags) {
 769                         rcu_read_unlock();
 770                         return found;
 771                 }
 772         }
 773         rcu_read_unlock();
 774         return NULL;
 775 }
 776
 777 /*
 778  * after adding space to the filesystem, we need to clear the full flags
 779  * on all the space infos.
 780  */
 781 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 782 {
 783         struct list_head *head = &info->space_info;
 784         struct btrfs_space_info *found;
 785
 786         rcu_read_lock();
 787         list_for_each_entry_rcu(found, head, list)
 788                 found->full = 0;
 789         rcu_read_unlock();
 790 }
 791
 792 /* simple helper to search for an existing data extent at a given offset */
 793 int btrfs_lookup_data_extent(struct btrfs_root *root, u64 start, u64 len)
 794 {
 795         int ret;
 796         struct btrfs_key key;
 797         struct btrfs_path *path;
 798
 799         path = btrfs_alloc_path();
 800         if (!path)
 801                 return -ENOMEM;
 802
 803         key.objectid = start;
 804         key.offset = len;
 805         key.type = BTRFS_EXTENT_ITEM_KEY;
 806         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 807                                 0, 0);
 808         btrfs_free_path(path);
 809         return ret;
 810 }
 811
 812 /*
 813  * helper function to lookup reference count and flags of a tree block.
 814  *
 815  * the head node for delayed ref is used to store the sum of all the
 816  * reference count modifications queued up in the rbtree. the head
 817  * node may also store the extent flags to set. This way you can check
 818  * to see what the reference count and extent flags would be if all of
 819  * the delayed refs are not processed.
 820  */
 821 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 822                              struct btrfs_root *root, u64 bytenr,
 823                              u64 offset, int metadata, u64 *refs, u64 *flags)
 824 {
 825         struct btrfs_delayed_ref_head *head;
 826         struct btrfs_delayed_ref_root *delayed_refs;
 827         struct btrfs_path *path;
 828         struct btrfs_extent_item *ei;
 829         struct extent_buffer *leaf;
 830         struct btrfs_key key;
 831         u32 item_size;
 832         u64 num_refs;
 833         u64 extent_flags;
 834         int ret;
 835
 836         /*
 837          * If we don't have skinny metadata, don't bother doing anything
 838          * different
 839          */
 840         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA)) {
 841                 offset = root->nodesize;
 842                 metadata = 0;
 843         }
 844
 845         path = btrfs_alloc_path();
 846         if (!path)
 847                 return -ENOMEM;
 848
 849         if (!trans) {
 850                 path->skip_locking = 1;
 851                 path->search_commit_root = 1;
 852         }
 853
 854 search_again:
 855         key.objectid = bytenr;
 856         key.offset = offset;
 857         if (metadata)
 858                 key.type = BTRFS_METADATA_ITEM_KEY;
 859         else
 860                 key.type = BTRFS_EXTENT_ITEM_KEY;
 861
 862         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 863                                 &key, path, 0, 0);
 864         if (ret < 0)
 865                 goto out_free;
 866
 867         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 868                 if (path->slots[0]) {
 869                         path->slots[0]--;
 870                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 871                                               path->slots[0]);
 872                         if (key.objectid == bytenr &&
 873                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 874                             key.offset == root->nodesize)
 875                                 ret = 0;
 876                 }
 877         }
 878
 879         if (ret == 0) {
 880                 leaf = path->nodes[0];
 881                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 882                 if (item_size >= sizeof(*ei)) {
 883                         ei = btrfs_item_ptr(leaf, path->slots[0],
 884                                             struct btrfs_extent_item);
 885                         num_refs = btrfs_extent_refs(leaf, ei);
 886                         extent_flags = btrfs_extent_flags(leaf, ei);
 887                 } else {
 888 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 889                         struct btrfs_extent_item_v0 *ei0;
 890                         BUG_ON(item_size != sizeof(*ei0));
 891                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 892                                              struct btrfs_extent_item_v0);
 893                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 894                         /* FIXME: this isn't correct for data */
 895                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 896 #else
 897                         BUG();
 898 #endif
 899                 }
 900                 BUG_ON(num_refs == 0);
 901         } else {
 902                 num_refs = 0;
 903                 extent_flags = 0;
 904                 ret = 0;
 905         }
 906
 907         if (!trans)
 908                 goto out;
 909
 910         delayed_refs = &trans->transaction->delayed_refs;
 911         spin_lock(&delayed_refs->lock);
 912         head = btrfs_find_delayed_ref_head(trans, bytenr);
 913         if (head) {
 914                 if (!mutex_trylock(&head->mutex)) {
 915                         atomic_inc(&head->node.refs);
 916                         spin_unlock(&delayed_refs->lock);
 917
 918                         btrfs_release_path(path);
 919
 920                         /*
 921                          * Mutex was contended, block until it's released and try
 922                          * again
 923                          */
 924                         mutex_lock(&head->mutex);
 925                         mutex_unlock(&head->mutex);
 926                         btrfs_put_delayed_ref(&head->node);
 927                         goto search_again;
 928                 }
 929                 spin_lock(&head->lock);
 930                 if (head->extent_op && head->extent_op->update_flags)
 931                         extent_flags |= head->extent_op->flags_to_set;
 932                 else
 933                         BUG_ON(num_refs == 0);
 934
 935                 num_refs += head->node.ref_mod;
 936                 spin_unlock(&head->lock);
 937                 mutex_unlock(&head->mutex);
 938         }
 939         spin_unlock(&delayed_refs->lock);
 940 out:
 941         WARN_ON(num_refs == 0);
 942         if (refs)
 943                 *refs = num_refs;
 944         if (flags)
 945                 *flags = extent_flags;
 946 out_free:
 947         btrfs_free_path(path);
 948         return ret;
 949 }
 950
 951 /*
 952  * Back reference rules.  Back refs have three main goals:
 953  *
 954  * 1) differentiate between all holders of references to an extent so that
 955  *    when a reference is dropped we can make sure it was a valid reference
 956  *    before freeing the extent.
 957  *
 958  * 2) Provide enough information to quickly find the holders of an extent
 959  *    if we notice a given block is corrupted or bad.
 960  *
 961  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 962  *    maintenance.  This is actually the same as #2, but with a slightly
 963  *    different use case.
 964  *
 965  * There are two kinds of back refs. The implicit back refs is optimized
 966  * for pointers in non-shared tree blocks. For a given pointer in a block,
 967  * back refs of this kind provide information about the block's owner tree
 968  * and the pointer's key. These information allow us to find the block by
 969  * b-tree searching. The full back refs is for pointers in tree blocks not
 970  * referenced by their owner trees. The location of tree block is recorded
 971  * in the back refs. Actually the full back refs is generic, and can be
 972  * used in all cases the implicit back refs is used. The major shortcoming
 973  * of the full back refs is its overhead. Every time a tree block gets
 974  * COWed, we have to update back refs entry for all pointers in it.
 975  *
 976  * For a newly allocated tree block, we use implicit back refs for
 977  * pointers in it. This means most tree related operations only involve
 978  * implicit back refs. For a tree block created in old transaction, the
 979  * only way to drop a reference to it is COW it. So we can detect the
 980  * event that tree block loses its owner tree's reference and do the
 981  * back refs conversion.
 982  *
 983  * When a tree block is COW'd through a tree, there are four cases:
 984  *
 985  * The reference count of the block is one and the tree is the block's
 986  * owner tree. Nothing to do in this case.
 987  *
 988  * The reference count of the block is one and the tree is not the
 989  * block's owner tree. In this case, full back refs is used for pointers
 990  * in the block. Remove these full back refs, add implicit back refs for
 991  * every pointers in the new block.
 992  *
 993  * The reference count of the block is greater than one and the tree is
 994  * the block's owner tree. In this case, implicit back refs is used for
 995  * pointers in the block. Add full back refs for every pointers in the
 996  * block, increase lower level extents' reference counts. The original
 997  * implicit back refs are entailed to the new block.
 998  *
 999  * The reference count of the block is greater than one and the tree is
1000  * not the block's owner tree. Add implicit back refs for every pointer in
1001  * the new block, increase lower level extents' reference count.
1002  *
1003  * Back Reference Key composing:
1004  *
1005  * The key objectid corresponds to the first byte in the extent,
1006  * The key type is used to differentiate between types of back refs.
1007  * There are different meanings of the key offset for different types
1008  * of back refs.
1009  *
1010  * File extents can be referenced by:
1011  *
1012  * - multiple snapshots, subvolumes, or different generations in one subvol
1013  * - different files inside a single subvolume
1014  * - different offsets inside a file (bookend extents in file.c)
1015  *
1016  * The extent ref structure for the implicit back refs has fields for:
1017  *
1018  * - Objectid of the subvolume root
1019  * - objectid of the file holding the reference
1020  * - original offset in the file
1021  * - how many bookend extents
1022  *
1023  * The key offset for the implicit back refs is hash of the first
1024  * three fields.
1025  *
1026  * The extent ref structure for the full back refs has field for:
1027  *
1028  * - number of pointers in the tree leaf
1029  *
1030  * The key offset for the implicit back refs is the first byte of
1031  * the tree leaf
1032  *
1033  * When a file extent is allocated, The implicit back refs is used.
1034  * the fields are filled in:
1035  *
1036  *     (root_key.objectid, inode objectid, offset in file, 1)
1037  *
1038  * When a file extent is removed file truncation, we find the
1039  * corresponding implicit back refs and check the following fields:
1040  *
1041  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
1042  *
1043  * Btree extents can be referenced by:
1044  *
1045  * - Different subvolumes
1046  *
1047  * Both the implicit back refs and the full back refs for tree blocks
1048  * only consist of key. The key offset for the implicit back refs is
1049  * objectid of block's owner tree. The key offset for the full back refs
1050  * is the first byte of parent block.
1051  *
1052  * When implicit back refs is used, information about the lowest key and
1053  * level of the tree block are required. These information are stored in
1054  * tree block info structure.
1055  */
1056
1057 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1058 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
1059                                   struct btrfs_root *root,
1060                                   struct btrfs_path *path,
1061                                   u64 owner, u32 extra_size)
1062 {
1063         struct btrfs_extent_item *item;
1064         struct btrfs_extent_item_v0 *ei0;
1065         struct btrfs_extent_ref_v0 *ref0;
1066         struct btrfs_tree_block_info *bi;
1067         struct extent_buffer *leaf;
1068         struct btrfs_key key;
1069         struct btrfs_key found_key;
1070         u32 new_size = sizeof(*item);
1071         u64 refs;
1072         int ret;
1073
1074         leaf = path->nodes[0];
1075         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
1076
1077         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1078         ei0 = btrfs_item_ptr(leaf, path->slots[0],
1079                              struct btrfs_extent_item_v0);
1080         refs = btrfs_extent_refs_v0(leaf, ei0);
1081
1082         if (owner == (u64)-1) {
1083                 while (1) {
1084                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1085                                 ret = btrfs_next_leaf(root, path);
1086                                 if (ret < 0)
1087                                         return ret;
1088                                 BUG_ON(ret > 0); /* Corruption */
1089                                 leaf = path->nodes[0];
1090                         }
1091                         btrfs_item_key_to_cpu(leaf, &found_key,
1092                                               path->slots[0]);
1093                         BUG_ON(key.objectid != found_key.objectid);
1094                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
1095                                 path->slots[0]++;
1096                                 continue;
1097                         }
1098                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1099                                               struct btrfs_extent_ref_v0);
1100                         owner = btrfs_ref_objectid_v0(leaf, ref0);
1101                         break;
1102                 }
1103         }
1104         btrfs_release_path(path);
1105
1106         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1107                 new_size += sizeof(*bi);
1108
1109         new_size -= sizeof(*ei0);
1110         ret = btrfs_search_slot(trans, root, &key, path,
1111                                 new_size + extra_size, 1);
1112         if (ret < 0)
1113                 return ret;
1114         BUG_ON(ret); /* Corruption */
1115
1116         btrfs_extend_item(root, path, new_size);
1117
1118         leaf = path->nodes[0];
1119         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1120         btrfs_set_extent_refs(leaf, item, refs);
1121         /* FIXME: get real generation */
1122         btrfs_set_extent_generation(leaf, item, 0);
1123         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1124                 btrfs_set_extent_flags(leaf, item,
1125                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1126                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1127                 bi = (struct btrfs_tree_block_info *)(item + 1);
1128                 /* FIXME: get first key of the block */
1129                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1130                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1131         } else {
1132                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1133         }
1134         btrfs_mark_buffer_dirty(leaf);
1135         return 0;
1136 }
1137 #endif
1138
1139 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1140 {
1141         u32 high_crc = ~(u32)0;
1142         u32 low_crc = ~(u32)0;
1143         __le64 lenum;
1144
1145         lenum = cpu_to_le64(root_objectid);
1146         high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
1147         lenum = cpu_to_le64(owner);
1148         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1149         lenum = cpu_to_le64(offset);
1150         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1151
1152         return ((u64)high_crc << 31) ^ (u64)low_crc;
1153 }
1154
1155 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1156                                      struct btrfs_extent_data_ref *ref)
1157 {
1158         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1159                                     btrfs_extent_data_ref_objectid(leaf, ref),
1160                                     btrfs_extent_data_ref_offset(leaf, ref));
1161 }
1162
1163 static int match_extent_data_ref(struct extent_buffer *leaf,
1164                                  struct btrfs_extent_data_ref *ref,
1165                                  u64 root_objectid, u64 owner, u64 offset)
1166 {
1167         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1168             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1169             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1170                 return 0;
1171         return 1;
1172 }
1173
1174 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1175                                            struct btrfs_root *root,
1176                                            struct btrfs_path *path,
1177                                            u64 bytenr, u64 parent,
1178                                            u64 root_objectid,
1179                                            u64 owner, u64 offset)
1180 {
1181         struct btrfs_key key;
1182         struct btrfs_extent_data_ref *ref;
1183         struct extent_buffer *leaf;
1184         u32 nritems;
1185         int ret;
1186         int recow;
1187         int err = -ENOENT;
1188
1189         key.objectid = bytenr;
1190         if (parent) {
1191                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1192                 key.offset = parent;
1193         } else {
1194                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1195                 key.offset = hash_extent_data_ref(root_objectid,
1196                                                   owner, offset);
1197         }
1198 again:
1199         recow = 0;
1200         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1201         if (ret < 0) {
1202                 err = ret;
1203                 goto fail;
1204         }
1205
1206         if (parent) {
1207                 if (!ret)
1208                         return 0;
1209 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1210                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1211                 btrfs_release_path(path);
1212                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1213                 if (ret < 0) {
1214                         err = ret;
1215                         goto fail;
1216                 }
1217                 if (!ret)
1218                         return 0;
1219 #endif
1220                 goto fail;
1221         }
1222
1223         leaf = path->nodes[0];
1224         nritems = btrfs_header_nritems(leaf);
1225         while (1) {
1226                 if (path->slots[0] >= nritems) {
1227                         ret = btrfs_next_leaf(root, path);
1228                         if (ret < 0)
1229                                 err = ret;
1230                         if (ret)
1231                                 goto fail;
1232
1233                         leaf = path->nodes[0];
1234                         nritems = btrfs_header_nritems(leaf);
1235                         recow = 1;
1236                 }
1237
1238                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1239                 if (key.objectid != bytenr ||
1240                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1241                         goto fail;
1242
1243                 ref = btrfs_item_ptr(leaf, path->slots[0],
1244                                      struct btrfs_extent_data_ref);
1245
1246                 if (match_extent_data_ref(leaf, ref, root_objectid,
1247                                           owner, offset)) {
1248                         if (recow) {
1249                                 btrfs_release_path(path);
1250                                 goto again;
1251                         }
1252                         err = 0;
1253                         break;
1254                 }
1255                 path->slots[0]++;
1256         }
1257 fail:
1258         return err;
1259 }
1260
1261 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1262                                            struct btrfs_root *root,
1263                                            struct btrfs_path *path,
1264                                            u64 bytenr, u64 parent,
1265                                            u64 root_objectid, u64 owner,
1266                                            u64 offset, int refs_to_add)
1267 {
1268         struct btrfs_key key;
1269         struct extent_buffer *leaf;
1270         u32 size;
1271         u32 num_refs;
1272         int ret;
1273
1274         key.objectid = bytenr;
1275         if (parent) {
1276                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1277                 key.offset = parent;
1278                 size = sizeof(struct btrfs_shared_data_ref);
1279         } else {
1280                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1281                 key.offset = hash_extent_data_ref(root_objectid,
1282                                                   owner, offset);
1283                 size = sizeof(struct btrfs_extent_data_ref);
1284         }
1285
1286         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1287         if (ret && ret != -EEXIST)
1288                 goto fail;
1289
1290         leaf = path->nodes[0];
1291         if (parent) {
1292                 struct btrfs_shared_data_ref *ref;
1293                 ref = btrfs_item_ptr(leaf, path->slots[0],
1294                                      struct btrfs_shared_data_ref);
1295                 if (ret == 0) {
1296                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1297                 } else {
1298                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1299                         num_refs += refs_to_add;
1300                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1301                 }
1302         } else {
1303                 struct btrfs_extent_data_ref *ref;
1304                 while (ret == -EEXIST) {
1305                         ref = btrfs_item_ptr(leaf, path->slots[0],
1306                                              struct btrfs_extent_data_ref);
1307                         if (match_extent_data_ref(leaf, ref, root_objectid,
1308                                                   owner, offset))
1309                                 break;
1310                         btrfs_release_path(path);
1311                         key.offset++;
1312                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1313                                                       size);
1314                         if (ret && ret != -EEXIST)
1315                                 goto fail;
1316
1317                         leaf = path->nodes[0];
1318                 }
1319                 ref = btrfs_item_ptr(leaf, path->slots[0],
1320                                      struct btrfs_extent_data_ref);
1321                 if (ret == 0) {
1322                         btrfs_set_extent_data_ref_root(leaf, ref,
1323                                                        root_objectid);
1324                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1325                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1326                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1327                 } else {
1328                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1329                         num_refs += refs_to_add;
1330                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1331                 }
1332         }
1333         btrfs_mark_buffer_dirty(leaf);
1334         ret = 0;
1335 fail:
1336         btrfs_release_path(path);
1337         return ret;
1338 }
1339
1340 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1341                                            struct btrfs_root *root,
1342                                            struct btrfs_path *path,
1343                                            int refs_to_drop, int *last_ref)
1344 {
1345         struct btrfs_key key;
1346         struct btrfs_extent_data_ref *ref1 = NULL;
1347         struct btrfs_shared_data_ref *ref2 = NULL;
1348         struct extent_buffer *leaf;
1349         u32 num_refs = 0;
1350         int ret = 0;
1351
1352         leaf = path->nodes[0];
1353         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1354
1355         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1356                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1357                                       struct btrfs_extent_data_ref);
1358                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1359         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1360                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1361                                       struct btrfs_shared_data_ref);
1362                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1363 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1364         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1365                 struct btrfs_extent_ref_v0 *ref0;
1366                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1367                                       struct btrfs_extent_ref_v0);
1368                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1369 #endif
1370         } else {
1371                 BUG();
1372         }
1373
1374         BUG_ON(num_refs < refs_to_drop);
1375         num_refs -= refs_to_drop;
1376
1377         if (num_refs == 0) {
1378                 ret = btrfs_del_item(trans, root, path);
1379                 *last_ref = 1;
1380         } else {
1381                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1382                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1383                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1384                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1385 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1386                 else {
1387                         struct btrfs_extent_ref_v0 *ref0;
1388                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1389                                         struct btrfs_extent_ref_v0);
1390                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1391                 }
1392 #endif
1393                 btrfs_mark_buffer_dirty(leaf);
1394         }
1395         return ret;
1396 }
1397
1398 static noinline u32 extent_data_ref_count(struct btrfs_path *path,
1399                                           struct btrfs_extent_inline_ref *iref)
1400 {
1401         struct btrfs_key key;
1402         struct extent_buffer *leaf;
1403         struct btrfs_extent_data_ref *ref1;
1404         struct btrfs_shared_data_ref *ref2;
1405         u32 num_refs = 0;
1406
1407         leaf = path->nodes[0];
1408         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1409         if (iref) {
1410                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1411                     BTRFS_EXTENT_DATA_REF_KEY) {
1412                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1413                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1414                 } else {
1415                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1416                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1417                 }
1418         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1419                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1420                                       struct btrfs_extent_data_ref);
1421                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1422         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1423                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1424                                       struct btrfs_shared_data_ref);
1425                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1426 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1427         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1428                 struct btrfs_extent_ref_v0 *ref0;
1429                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1430                                       struct btrfs_extent_ref_v0);
1431                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1432 #endif
1433         } else {
1434                 WARN_ON(1);
1435         }
1436         return num_refs;
1437 }
1438
1439 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1440                                           struct btrfs_root *root,
1441                                           struct btrfs_path *path,
1442                                           u64 bytenr, u64 parent,
1443                                           u64 root_objectid)
1444 {
1445         struct btrfs_key key;
1446         int ret;
1447
1448         key.objectid = bytenr;
1449         if (parent) {
1450                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1451                 key.offset = parent;
1452         } else {
1453                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1454                 key.offset = root_objectid;
1455         }
1456
1457         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1458         if (ret > 0)
1459                 ret = -ENOENT;
1460 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1461         if (ret == -ENOENT && parent) {
1462                 btrfs_release_path(path);
1463                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1464                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1465                 if (ret > 0)
1466                         ret = -ENOENT;
1467         }
1468 #endif
1469         return ret;
1470 }
1471
1472 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1473                                           struct btrfs_root *root,
1474                                           struct btrfs_path *path,
1475                                           u64 bytenr, u64 parent,
1476                                           u64 root_objectid)
1477 {
1478         struct btrfs_key key;
1479         int ret;
1480
1481         key.objectid = bytenr;
1482         if (parent) {
1483                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1484                 key.offset = parent;
1485         } else {
1486                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1487                 key.offset = root_objectid;
1488         }
1489
1490         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1491         btrfs_release_path(path);
1492         return ret;
1493 }
1494
1495 static inline int extent_ref_type(u64 parent, u64 owner)
1496 {
1497         int type;
1498         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1499                 if (parent > 0)
1500                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1501                 else
1502                         type = BTRFS_TREE_BLOCK_REF_KEY;
1503         } else {
1504                 if (parent > 0)
1505                         type = BTRFS_SHARED_DATA_REF_KEY;
1506                 else
1507                         type = BTRFS_EXTENT_DATA_REF_KEY;
1508         }
1509         return type;
1510 }
1511
1512 static int find_next_key(struct btrfs_path *path, int level,
1513                          struct btrfs_key *key)
1514
1515 {
1516         for (; level < BTRFS_MAX_LEVEL; level++) {
1517                 if (!path->nodes[level])
1518                         break;
1519                 if (path->slots[level] + 1 >=
1520                     btrfs_header_nritems(path->nodes[level]))
1521                         continue;
1522                 if (level == 0)
1523                         btrfs_item_key_to_cpu(path->nodes[level], key,
1524                                               path->slots[level] + 1);
1525                 else
1526                         btrfs_node_key_to_cpu(path->nodes[level], key,
1527                                               path->slots[level] + 1);
1528                 return 0;
1529         }
1530         return 1;
1531 }
1532
1533 /*
1534  * look for inline back ref. if back ref is found, *ref_ret is set
1535  * to the address of inline back ref, and 0 is returned.
1536  *
1537  * if back ref isn't found, *ref_ret is set to the address where it
1538  * should be inserted, and -ENOENT is returned.
1539  *
1540  * if insert is true and there are too many inline back refs, the path
1541  * points to the extent item, and -EAGAIN is returned.
1542  *
1543  * NOTE: inline back refs are ordered in the same way that back ref
1544  *       items in the tree are ordered.
1545  */
1546 static noinline_for_stack
1547 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1548                                  struct btrfs_root *root,
1549                                  struct btrfs_path *path,
1550                                  struct btrfs_extent_inline_ref **ref_ret,
1551                                  u64 bytenr, u64 num_bytes,
1552                                  u64 parent, u64 root_objectid,
1553                                  u64 owner, u64 offset, int insert)
1554 {
1555         struct btrfs_key key;
1556         struct extent_buffer *leaf;
1557         struct btrfs_extent_item *ei;
1558         struct btrfs_extent_inline_ref *iref;
1559         u64 flags;
1560         u64 item_size;
1561         unsigned long ptr;
1562         unsigned long end;
1563         int extra_size;
1564         int type;
1565         int want;
1566         int ret;
1567         int err = 0;
1568         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
1569                                                  SKINNY_METADATA);
1570
1571         key.objectid = bytenr;
1572         key.type = BTRFS_EXTENT_ITEM_KEY;
1573         key.offset = num_bytes;
1574
1575         want = extent_ref_type(parent, owner);
1576         if (insert) {
1577                 extra_size = btrfs_extent_inline_ref_size(want);
1578                 path->keep_locks = 1;
1579         } else
1580                 extra_size = -1;
1581
1582         /*
1583          * Owner is our parent level, so we can just add one to get the level
1584          * for the block we are interested in.
1585          */
1586         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1587                 key.type = BTRFS_METADATA_ITEM_KEY;
1588                 key.offset = owner;
1589         }
1590
1591 again:
1592         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1593         if (ret < 0) {
1594                 err = ret;
1595                 goto out;
1596         }
1597
1598         /*
1599          * We may be a newly converted file system which still has the old fat
1600          * extent entries for metadata, so try and see if we have one of those.
1601          */
1602         if (ret > 0 && skinny_metadata) {
1603                 skinny_metadata = false;
1604                 if (path->slots[0]) {
1605                         path->slots[0]--;
1606                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1607                                               path->slots[0]);
1608                         if (key.objectid == bytenr &&
1609                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1610                             key.offset == num_bytes)
1611                                 ret = 0;
1612                 }
1613                 if (ret) {
1614                         key.objectid = bytenr;
1615                         key.type = BTRFS_EXTENT_ITEM_KEY;
1616                         key.offset = num_bytes;
1617                         btrfs_release_path(path);
1618                         goto again;
1619                 }
1620         }
1621
1622         if (ret && !insert) {
1623                 err = -ENOENT;
1624                 goto out;
1625         } else if (WARN_ON(ret)) {
1626                 err = -EIO;
1627                 goto out;
1628         }
1629
1630         leaf = path->nodes[0];
1631         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1632 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1633         if (item_size < sizeof(*ei)) {
1634                 if (!insert) {
1635                         err = -ENOENT;
1636                         goto out;
1637                 }
1638                 ret = convert_extent_item_v0(trans, root, path, owner,
1639                                              extra_size);
1640                 if (ret < 0) {
1641                         err = ret;
1642                         goto out;
1643                 }
1644                 leaf = path->nodes[0];
1645                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1646         }
1647 #endif
1648         BUG_ON(item_size < sizeof(*ei));
1649
1650         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1651         flags = btrfs_extent_flags(leaf, ei);
1652
1653         ptr = (unsigned long)(ei + 1);
1654         end = (unsigned long)ei + item_size;
1655
1656         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1657                 ptr += sizeof(struct btrfs_tree_block_info);
1658                 BUG_ON(ptr > end);
1659         }
1660
1661         err = -ENOENT;
1662         while (1) {
1663                 if (ptr >= end) {
1664                         WARN_ON(ptr > end);
1665                         break;
1666                 }
1667                 iref = (struct btrfs_extent_inline_ref *)ptr;
1668                 type = btrfs_extent_inline_ref_type(leaf, iref);
1669                 if (want < type)
1670                         break;
1671                 if (want > type) {
1672                         ptr += btrfs_extent_inline_ref_size(type);
1673                         continue;
1674                 }
1675
1676                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1677                         struct btrfs_extent_data_ref *dref;
1678                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1679                         if (match_extent_data_ref(leaf, dref, root_objectid,
1680                                                   owner, offset)) {
1681                                 err = 0;
1682                                 break;
1683                         }
1684                         if (hash_extent_data_ref_item(leaf, dref) <
1685                             hash_extent_data_ref(root_objectid, owner, offset))
1686                                 break;
1687                 } else {
1688                         u64 ref_offset;
1689                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1690                         if (parent > 0) {
1691                                 if (parent == ref_offset) {
1692                                         err = 0;
1693                                         break;
1694                                 }
1695                                 if (ref_offset < parent)
1696                                         break;
1697                         } else {
1698                                 if (root_objectid == ref_offset) {
1699                                         err = 0;
1700                                         break;
1701                                 }
1702                                 if (ref_offset < root_objectid)
1703                                         break;
1704                         }
1705                 }
1706                 ptr += btrfs_extent_inline_ref_size(type);
1707         }
1708         if (err == -ENOENT && insert) {
1709                 if (item_size + extra_size >=
1710                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1711                         err = -EAGAIN;
1712                         goto out;
1713                 }
1714                 /*
1715                  * To add new inline back ref, we have to make sure
1716                  * there is no corresponding back ref item.
1717                  * For simplicity, we just do not add new inline back
1718                  * ref if there is any kind of item for this block
1719                  */
1720                 if (find_next_key(path, 0, &key) == 0 &&
1721                     key.objectid == bytenr &&
1722                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1723                         err = -EAGAIN;
1724                         goto out;
1725                 }
1726         }
1727         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1728 out:
1729         if (insert) {
1730                 path->keep_locks = 0;
1731                 btrfs_unlock_up_safe(path, 1);
1732         }
1733         return err;
1734 }
1735
1736 /*
1737  * helper to add new inline back ref
1738  */
1739 static noinline_for_stack
1740 void setup_inline_extent_backref(struct btrfs_root *root,
1741                                  struct btrfs_path *path,
1742                                  struct btrfs_extent_inline_ref *iref,
1743                                  u64 parent, u64 root_objectid,
1744                                  u64 owner, u64 offset, int refs_to_add,
1745                                  struct btrfs_delayed_extent_op *extent_op)
1746 {
1747         struct extent_buffer *leaf;
1748         struct btrfs_extent_item *ei;
1749         unsigned long ptr;
1750         unsigned long end;
1751         unsigned long item_offset;
1752         u64 refs;
1753         int size;
1754         int type;
1755
1756         leaf = path->nodes[0];
1757         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1758         item_offset = (unsigned long)iref - (unsigned long)ei;
1759
1760         type = extent_ref_type(parent, owner);
1761         size = btrfs_extent_inline_ref_size(type);
1762
1763         btrfs_extend_item(root, path, size);
1764
1765         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1766         refs = btrfs_extent_refs(leaf, ei);
1767         refs += refs_to_add;
1768         btrfs_set_extent_refs(leaf, ei, refs);
1769         if (extent_op)
1770                 __run_delayed_extent_op(extent_op, leaf, ei);
1771
1772         ptr = (unsigned long)ei + item_offset;
1773         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1774         if (ptr < end - size)
1775                 memmove_extent_buffer(leaf, ptr + size, ptr,
1776                                       end - size - ptr);
1777
1778         iref = (struct btrfs_extent_inline_ref *)ptr;
1779         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1780         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1781                 struct btrfs_extent_data_ref *dref;
1782                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1783                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1784                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1785                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1786                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1787         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1788                 struct btrfs_shared_data_ref *sref;
1789                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1790                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1791                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1792         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1793                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1794         } else {
1795                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1796         }
1797         btrfs_mark_buffer_dirty(leaf);
1798 }
1799
1800 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1801                                  struct btrfs_root *root,
1802                                  struct btrfs_path *path,
1803                                  struct btrfs_extent_inline_ref **ref_ret,
1804                                  u64 bytenr, u64 num_bytes, u64 parent,
1805                                  u64 root_objectid, u64 owner, u64 offset)
1806 {
1807         int ret;
1808
1809         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1810                                            bytenr, num_bytes, parent,
1811                                            root_objectid, owner, offset, 0);
1812         if (ret != -ENOENT)
1813                 return ret;
1814
1815         btrfs_release_path(path);
1816         *ref_ret = NULL;
1817
1818         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1819                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1820                                             root_objectid);
1821         } else {
1822                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1823                                              root_objectid, owner, offset);
1824         }
1825         return ret;
1826 }
1827
1828 /*
1829  * helper to update/remove inline back ref
1830  */
1831 static noinline_for_stack
1832 void update_inline_extent_backref(struct btrfs_root *root,
1833                                   struct btrfs_path *path,
1834                                   struct btrfs_extent_inline_ref *iref,
1835                                   int refs_to_mod,
1836                                   struct btrfs_delayed_extent_op *extent_op,
1837                                   int *last_ref)
1838 {
1839         struct extent_buffer *leaf;
1840         struct btrfs_extent_item *ei;
1841         struct btrfs_extent_data_ref *dref = NULL;
1842         struct btrfs_shared_data_ref *sref = NULL;
1843         unsigned long ptr;
1844         unsigned long end;
1845         u32 item_size;
1846         int size;
1847         int type;
1848         u64 refs;
1849
1850         leaf = path->nodes[0];
1851         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1852         refs = btrfs_extent_refs(leaf, ei);
1853         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1854         refs += refs_to_mod;
1855         btrfs_set_extent_refs(leaf, ei, refs);
1856         if (extent_op)
1857                 __run_delayed_extent_op(extent_op, leaf, ei);
1858
1859         type = btrfs_extent_inline_ref_type(leaf, iref);
1860
1861         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1862                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1863                 refs = btrfs_extent_data_ref_count(leaf, dref);
1864         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1865                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1866                 refs = btrfs_shared_data_ref_count(leaf, sref);
1867         } else {
1868                 refs = 1;
1869                 BUG_ON(refs_to_mod != -1);
1870         }
1871
1872         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1873         refs += refs_to_mod;
1874
1875         if (refs > 0) {
1876                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1877                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1878                 else
1879                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1880         } else {
1881                 *last_ref = 1;
1882                 size =  btrfs_extent_inline_ref_size(type);
1883                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1884                 ptr = (unsigned long)iref;
1885                 end = (unsigned long)ei + item_size;
1886                 if (ptr + size < end)
1887                         memmove_extent_buffer(leaf, ptr, ptr + size,
1888                                               end - ptr - size);
1889                 item_size -= size;
1890                 btrfs_truncate_item(root, path, item_size, 1);
1891         }
1892         btrfs_mark_buffer_dirty(leaf);
1893 }
1894
1895 static noinline_for_stack
1896 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1897                                  struct btrfs_root *root,
1898                                  struct btrfs_path *path,
1899                                  u64 bytenr, u64 num_bytes, u64 parent,
1900                                  u64 root_objectid, u64 owner,
1901                                  u64 offset, int refs_to_add,
1902                                  struct btrfs_delayed_extent_op *extent_op)
1903 {
1904         struct btrfs_extent_inline_ref *iref;
1905         int ret;
1906
1907         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1908                                            bytenr, num_bytes, parent,
1909                                            root_objectid, owner, offset, 1);
1910         if (ret == 0) {
1911                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1912                 update_inline_extent_backref(root, path, iref,
1913                                              refs_to_add, extent_op, NULL);
1914         } else if (ret == -ENOENT) {
1915                 setup_inline_extent_backref(root, path, iref, parent,
1916                                             root_objectid, owner, offset,
1917                                             refs_to_add, extent_op);
1918                 ret = 0;
1919         }
1920         return ret;
1921 }
1922
1923 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1924                                  struct btrfs_root *root,
1925                                  struct btrfs_path *path,
1926                                  u64 bytenr, u64 parent, u64 root_objectid,
1927                                  u64 owner, u64 offset, int refs_to_add)
1928 {
1929         int ret;
1930         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1931                 BUG_ON(refs_to_add != 1);
1932                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1933                                             parent, root_objectid);
1934         } else {
1935                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1936                                              parent, root_objectid,
1937                                              owner, offset, refs_to_add);
1938         }
1939         return ret;
1940 }
1941
1942 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1943                                  struct btrfs_root *root,
1944                                  struct btrfs_path *path,
1945                                  struct btrfs_extent_inline_ref *iref,
1946                                  int refs_to_drop, int is_data, int *last_ref)
1947 {
1948         int ret = 0;
1949
1950         BUG_ON(!is_data && refs_to_drop != 1);
1951         if (iref) {
1952                 update_inline_extent_backref(root, path, iref,
1953                                              -refs_to_drop, NULL, last_ref);
1954         } else if (is_data) {
1955                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop,
1956                                              last_ref);
1957         } else {
1958                 *last_ref = 1;
1959                 ret = btrfs_del_item(trans, root, path);
1960         }
1961         return ret;
1962 }
1963
1964 #define in_range(b, first, len)        ((b) >= (first) && (b) < (first) + (len))
1965 static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
1966                                u64 *discarded_bytes)
1967 {
1968         int j, ret = 0;
1969         u64 bytes_left, end;
1970         u64 aligned_start = ALIGN(start, 1 << 9);
1971
1972         if (WARN_ON(start != aligned_start)) {
1973                 len -= aligned_start - start;
1974                 len = round_down(len, 1 << 9);
1975                 start = aligned_start;
1976         }
1977
1978         *discarded_bytes = 0;
1979
1980         if (!len)
1981                 return 0;
1982
1983         end = start + len;
1984         bytes_left = len;
1985
1986         /* Skip any superblocks on this device. */
1987         for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
1988                 u64 sb_start = btrfs_sb_offset(j);
1989                 u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
1990                 u64 size = sb_start - start;
1991
1992                 if (!in_range(sb_start, start, bytes_left) &&
1993                     !in_range(sb_end, start, bytes_left) &&
1994                     !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
1995                         continue;
1996
1997                 /*
1998                  * Superblock spans beginning of range.  Adjust start and
1999                  * try again.
2000                  */
2001                 if (sb_start <= start) {
2002                         start += sb_end - start;
2003                         if (start > end) {
2004                                 bytes_left = 0;
2005                                 break;
2006                         }
2007                         bytes_left = end - start;
2008                         continue;
2009                 }
2010
2011                 if (size) {
2012                         ret = blkdev_issue_discard(bdev, start >> 9, size >> 9,
2013                                                    GFP_NOFS, 0);
2014                         if (!ret)
2015                                 *discarded_bytes += size;
2016                         else if (ret != -EOPNOTSUPP)
2017                                 return ret;
2018                 }
2019
2020                 start = sb_end;
2021                 if (start > end) {
2022                         bytes_left = 0;
2023                         break;
2024                 }
2025                 bytes_left = end - start;
2026         }
2027
2028         if (bytes_left) {
2029                 ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9,
2030                                            GFP_NOFS, 0);
2031                 if (!ret)
2032                         *discarded_bytes += bytes_left;
2033         }
2034         return ret;
2035 }
2036
2037 int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
2038                          u64 num_bytes, u64 *actual_bytes)
2039 {
2040         int ret;
2041         u64 discarded_bytes = 0;
2042         struct btrfs_bio *bbio = NULL;
2043
2044
2045         /* Tell the block device(s) that the sectors can be discarded */
2046         ret = btrfs_map_block(root->fs_info, REQ_DISCARD,
2047                               bytenr, &num_bytes, &bbio, 0);
2048         /* Error condition is -ENOMEM */
2049         if (!ret) {
2050                 struct btrfs_bio_stripe *stripe = bbio->stripes;
2051                 int i;
2052
2053
2054                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
2055                         u64 bytes;
2056                         if (!stripe->dev->can_discard)
2057                                 continue;
2058
2059                         ret = btrfs_issue_discard(stripe->dev->bdev,
2060                                                   stripe->physical,
2061                                                   stripe->length,
2062                                                   &bytes);
2063                         if (!ret)
2064                                 discarded_bytes += bytes;
2065                         else if (ret != -EOPNOTSUPP)
2066                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
2067
2068                         /*
2069                          * Just in case we get back EOPNOTSUPP for some reason,
2070                          * just ignore the return value so we don't screw up
2071                          * people calling discard_extent.
2072                          */
2073                         ret = 0;
2074                 }
2075                 btrfs_put_bbio(bbio);
2076         }
2077
2078         if (actual_bytes)
2079                 *actual_bytes = discarded_bytes;
2080
2081
2082         if (ret == -EOPNOTSUPP)
2083                 ret = 0;
2084         return ret;
2085 }
2086
2087 /* Can return -ENOMEM */
2088 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2089                          struct btrfs_root *root,
2090                          u64 bytenr, u64 num_bytes, u64 parent,
2091                          u64 root_objectid, u64 owner, u64 offset)
2092 {
2093         int ret;
2094         struct btrfs_fs_info *fs_info = root->fs_info;
2095
2096         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
2097                root_objectid == BTRFS_TREE_LOG_OBJECTID);
2098
2099         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
2100                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
2101                                         num_bytes,
2102                                         parent, root_objectid, (int)owner,
2103                                         BTRFS_ADD_DELAYED_REF, NULL);
2104         } else {
2105                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
2106                                         num_bytes, parent, root_objectid,
2107                                         owner, offset, 0,
2108                                         BTRFS_ADD_DELAYED_REF, NULL);
2109         }
2110         return ret;
2111 }
2112
2113 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2114                                   struct btrfs_root *root,
2115                                   struct btrfs_delayed_ref_node *node,
2116                                   u64 parent, u64 root_objectid,
2117                                   u64 owner, u64 offset, int refs_to_add,
2118                                   struct btrfs_delayed_extent_op *extent_op)
2119 {
2120         struct btrfs_fs_info *fs_info = root->fs_info;
2121         struct btrfs_path *path;
2122         struct extent_buffer *leaf;
2123         struct btrfs_extent_item *item;
2124         struct btrfs_key key;
2125         u64 bytenr = node->bytenr;
2126         u64 num_bytes = node->num_bytes;
2127         u64 refs;
2128         int ret;
2129
2130         path = btrfs_alloc_path();
2131         if (!path)
2132                 return -ENOMEM;
2133
2134         path->reada = READA_FORWARD;
2135         path->leave_spinning = 1;
2136         /* this will setup the path even if it fails to insert the back ref */
2137         ret = insert_inline_extent_backref(trans, fs_info->extent_root, path,
2138                                            bytenr, num_bytes, parent,
2139                                            root_objectid, owner, offset,
2140                                            refs_to_add, extent_op);
2141         if ((ret < 0 && ret != -EAGAIN) || !ret)
2142                 goto out;
2143
2144         /*
2145          * Ok we had -EAGAIN which means we didn't have space to insert and
2146          * inline extent ref, so just update the reference count and add a
2147          * normal backref.
2148          */
2149         leaf = path->nodes[0];
2150         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2151         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2152         refs = btrfs_extent_refs(leaf, item);
2153         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2154         if (extent_op)
2155                 __run_delayed_extent_op(extent_op, leaf, item);
2156
2157         btrfs_mark_buffer_dirty(leaf);
2158         btrfs_release_path(path);
2159
2160         path->reada = READA_FORWARD;
2161         path->leave_spinning = 1;
2162         /* now insert the actual backref */
2163         ret = insert_extent_backref(trans, root->fs_info->extent_root,
2164                                     path, bytenr, parent, root_objectid,
2165                                     owner, offset, refs_to_add);
2166         if (ret)
2167                 btrfs_abort_transaction(trans, root, ret);
2168 out:
2169         btrfs_free_path(path);
2170         return ret;
2171 }
2172
2173 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2174                                 struct btrfs_root *root,
2175                                 struct btrfs_delayed_ref_node *node,
2176                                 struct btrfs_delayed_extent_op *extent_op,
2177                                 int insert_reserved)
2178 {
2179         int ret = 0;
2180         struct btrfs_delayed_data_ref *ref;
2181         struct btrfs_key ins;
2182         u64 parent = 0;
2183         u64 ref_root = 0;
2184         u64 flags = 0;
2185
2186         ins.objectid = node->bytenr;
2187         ins.offset = node->num_bytes;
2188         ins.type = BTRFS_EXTENT_ITEM_KEY;
2189
2190         ref = btrfs_delayed_node_to_data_ref(node);
2191         trace_run_delayed_data_ref(node, ref, node->action);
2192
2193         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2194                 parent = ref->parent;
2195         ref_root = ref->root;
2196
2197         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2198                 if (extent_op)
2199                         flags |= extent_op->flags_to_set;
2200                 ret = alloc_reserved_file_extent(trans, root,
2201                                                  parent, ref_root, flags,
2202                                                  ref->objectid, ref->offset,
2203                                                  &ins, node->ref_mod);
2204         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2205                 ret = __btrfs_inc_extent_ref(trans, root, node, parent,
2206                                              ref_root, ref->objectid,
2207                                              ref->offset, node->ref_mod,
2208                                              extent_op);
2209         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2210                 ret = __btrfs_free_extent(trans, root, node, parent,
2211                                           ref_root, ref->objectid,
2212                                           ref->offset, node->ref_mod,
2213                                           extent_op);
2214         } else {
2215                 BUG();
2216         }
2217         return ret;
2218 }
2219
2220 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2221                                     struct extent_buffer *leaf,
2222                                     struct btrfs_extent_item *ei)
2223 {
2224         u64 flags = btrfs_extent_flags(leaf, ei);
2225         if (extent_op->update_flags) {
2226                 flags |= extent_op->flags_to_set;
2227                 btrfs_set_extent_flags(leaf, ei, flags);
2228         }
2229
2230         if (extent_op->update_key) {
2231                 struct btrfs_tree_block_info *bi;
2232                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2233                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2234                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2235         }
2236 }
2237
2238 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2239                                  struct btrfs_root *root,
2240                                  struct btrfs_delayed_ref_node *node,
2241                                  struct btrfs_delayed_extent_op *extent_op)
2242 {
2243         struct btrfs_key key;
2244         struct btrfs_path *path;
2245         struct btrfs_extent_item *ei;
2246         struct extent_buffer *leaf;
2247         u32 item_size;
2248         int ret;
2249         int err = 0;
2250         int metadata = !extent_op->is_data;
2251
2252         if (trans->aborted)
2253                 return 0;
2254
2255         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2256                 metadata = 0;
2257
2258         path = btrfs_alloc_path();
2259         if (!path)
2260                 return -ENOMEM;
2261
2262         key.objectid = node->bytenr;
2263
2264         if (metadata) {
2265                 key.type = BTRFS_METADATA_ITEM_KEY;
2266                 key.offset = extent_op->level;
2267         } else {
2268                 key.type = BTRFS_EXTENT_ITEM_KEY;
2269                 key.offset = node->num_bytes;
2270         }
2271
2272 again:
2273         path->reada = READA_FORWARD;
2274         path->leave_spinning = 1;
2275         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2276                                 path, 0, 1);
2277         if (ret < 0) {
2278                 err = ret;
2279                 goto out;
2280         }
2281         if (ret > 0) {
2282                 if (metadata) {
2283                         if (path->slots[0] > 0) {
2284                                 path->slots[0]--;
2285                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
2286                                                       path->slots[0]);
2287                                 if (key.objectid == node->bytenr &&
2288                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
2289                                     key.offset == node->num_bytes)
2290                                         ret = 0;
2291                         }
2292                         if (ret > 0) {
2293                                 btrfs_release_path(path);
2294                                 metadata = 0;
2295
2296                                 key.objectid = node->bytenr;
2297                                 key.offset = node->num_bytes;
2298                                 key.type = BTRFS_EXTENT_ITEM_KEY;
2299                                 goto again;
2300                         }
2301                 } else {
2302                         err = -EIO;
2303                         goto out;
2304                 }
2305         }
2306
2307         leaf = path->nodes[0];
2308         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2309 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2310         if (item_size < sizeof(*ei)) {
2311                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2312                                              path, (u64)-1, 0);
2313                 if (ret < 0) {
2314                         err = ret;
2315                         goto out;
2316                 }
2317                 leaf = path->nodes[0];
2318                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2319         }
2320 #endif
2321         BUG_ON(item_size < sizeof(*ei));
2322         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2323         __run_delayed_extent_op(extent_op, leaf, ei);
2324
2325         btrfs_mark_buffer_dirty(leaf);
2326 out:
2327         btrfs_free_path(path);
2328         return err;
2329 }
2330
2331 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2332                                 struct btrfs_root *root,
2333                                 struct btrfs_delayed_ref_node *node,
2334                                 struct btrfs_delayed_extent_op *extent_op,
2335                                 int insert_reserved)
2336 {
2337         int ret = 0;
2338         struct btrfs_delayed_tree_ref *ref;
2339         struct btrfs_key ins;
2340         u64 parent = 0;
2341         u64 ref_root = 0;
2342         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
2343                                                  SKINNY_METADATA);
2344
2345         ref = btrfs_delayed_node_to_tree_ref(node);
2346         trace_run_delayed_tree_ref(node, ref, node->action);
2347
2348         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2349                 parent = ref->parent;
2350         ref_root = ref->root;
2351
2352         ins.objectid = node->bytenr;
2353         if (skinny_metadata) {
2354                 ins.offset = ref->level;
2355                 ins.type = BTRFS_METADATA_ITEM_KEY;
2356         } else {
2357                 ins.offset = node->num_bytes;
2358                 ins.type = BTRFS_EXTENT_ITEM_KEY;
2359         }
2360
2361         BUG_ON(node->ref_mod != 1);
2362         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2363                 BUG_ON(!extent_op || !extent_op->update_flags);
2364                 ret = alloc_reserved_tree_block(trans, root,
2365                                                 parent, ref_root,
2366                                                 extent_op->flags_to_set,
2367                                                 &extent_op->key,
2368                                                 ref->level, &ins);
2369         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2370                 ret = __btrfs_inc_extent_ref(trans, root, node,
2371                                              parent, ref_root,
2372                                              ref->level, 0, 1,
2373                                              extent_op);
2374         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2375                 ret = __btrfs_free_extent(trans, root, node,
2376                                           parent, ref_root,
2377                                           ref->level, 0, 1, extent_op);
2378         } else {
2379                 BUG();
2380         }
2381         return ret;
2382 }
2383
2384 /* helper function to actually process a single delayed ref entry */
2385 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2386                                struct btrfs_root *root,
2387                                struct btrfs_delayed_ref_node *node,
2388                                struct btrfs_delayed_extent_op *extent_op,
2389                                int insert_reserved)
2390 {
2391         int ret = 0;
2392
2393         if (trans->aborted) {
2394                 if (insert_reserved)
2395                         btrfs_pin_extent(root, node->bytenr,
2396                                          node->num_bytes, 1);
2397                 return 0;
2398         }
2399
2400         if (btrfs_delayed_ref_is_head(node)) {
2401                 struct btrfs_delayed_ref_head *head;
2402                 /*
2403                  * we've hit the end of the chain and we were supposed
2404                  * to insert this extent into the tree.  But, it got
2405                  * deleted before we ever needed to insert it, so all
2406                  * we have to do is clean up the accounting
2407                  */
2408                 BUG_ON(extent_op);
2409                 head = btrfs_delayed_node_to_head(node);
2410                 trace_run_delayed_ref_head(node, head, node->action);
2411
2412                 if (insert_reserved) {
2413                         btrfs_pin_extent(root, node->bytenr,
2414                                          node->num_bytes, 1);
2415                         if (head->is_data) {
2416                                 ret = btrfs_del_csums(trans, root,
2417                                                       node->bytenr,
2418                                                       node->num_bytes);
2419                         }
2420                 }
2421
2422                 /* Also free its reserved qgroup space */
2423                 btrfs_qgroup_free_delayed_ref(root->fs_info,
2424                                               head->qgroup_ref_root,
2425                                               head->qgroup_reserved);
2426                 return ret;
2427         }
2428
2429         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2430             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2431                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2432                                            insert_reserved);
2433         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2434                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2435                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2436                                            insert_reserved);
2437         else
2438                 BUG();
2439         return ret;
2440 }
2441
2442 static inline struct btrfs_delayed_ref_node *
2443 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2444 {
2445         struct btrfs_delayed_ref_node *ref;
2446
2447         if (list_empty(&head->ref_list))
2448                 return NULL;
2449
2450         /*
2451          * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
2452          * This is to prevent a ref count from going down to zero, which deletes
2453          * the extent item from the extent tree, when there still are references
2454          * to add, which would fail because they would not find the extent item.
2455          */
2456         list_for_each_entry(ref, &head->ref_list, list) {
2457                 if (ref->action == BTRFS_ADD_DELAYED_REF)
2458                         return ref;
2459         }
2460
2461         return list_entry(head->ref_list.next, struct btrfs_delayed_ref_node,
2462                           list);
2463 }
2464
2465 /*
2466  * Returns 0 on success or if called with an already aborted transaction.
2467  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2468  */
2469 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2470                                              struct btrfs_root *root,
2471                                              unsigned long nr)
2472 {
2473         struct btrfs_delayed_ref_root *delayed_refs;
2474         struct btrfs_delayed_ref_node *ref;
2475         struct btrfs_delayed_ref_head *locked_ref = NULL;
2476         struct btrfs_delayed_extent_op *extent_op;
2477         struct btrfs_fs_info *fs_info = root->fs_info;
2478         ktime_t start = ktime_get();
2479         int ret;
2480         unsigned long count = 0;
2481         unsigned long actual_count = 0;
2482         int must_insert_reserved = 0;
2483
2484         delayed_refs = &trans->transaction->delayed_refs;
2485         while (1) {
2486                 if (!locked_ref) {
2487                         if (count >= nr)
2488                                 break;
2489
2490                         spin_lock(&delayed_refs->lock);
2491                         locked_ref = btrfs_select_ref_head(trans);
2492                         if (!locked_ref) {
2493                                 spin_unlock(&delayed_refs->lock);
2494                                 break;
2495                         }
2496
2497                         /* grab the lock that says we are going to process
2498                          * all the refs for this head */
2499                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2500                         spin_unlock(&delayed_refs->lock);
2501                         /*
2502                          * we may have dropped the spin lock to get the head
2503                          * mutex lock, and that might have given someone else
2504                          * time to free the head.  If that's true, it has been
2505                          * removed from our list and we can move on.
2506                          */
2507                         if (ret == -EAGAIN) {
2508                                 locked_ref = NULL;
2509                                 count++;
2510                                 continue;
2511                         }
2512                 }
2513
2514                 /*
2515                  * We need to try and merge add/drops of the same ref since we
2516                  * can run into issues with relocate dropping the implicit ref
2517                  * and then it being added back again before the drop can
2518                  * finish.  If we merged anything we need to re-loop so we can
2519                  * get a good ref.
2520                  * Or we can get node references of the same type that weren't
2521                  * merged when created due to bumps in the tree mod seq, and
2522                  * we need to merge them to prevent adding an inline extent
2523                  * backref before dropping it (triggering a BUG_ON at
2524                  * insert_inline_extent_backref()).
2525                  */
2526                 spin_lock(&locked_ref->lock);
2527                 btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
2528                                          locked_ref);
2529
2530                 /*
2531                  * locked_ref is the head node, so we have to go one
2532                  * node back for any delayed ref updates
2533                  */
2534                 ref = select_delayed_ref(locked_ref);
2535
2536                 if (ref && ref->seq &&
2537                     btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2538                         spin_unlock(&locked_ref->lock);
2539                         btrfs_delayed_ref_unlock(locked_ref);
2540                         spin_lock(&delayed_refs->lock);
2541                         locked_ref->processing = 0;
2542                         delayed_refs->num_heads_ready++;
2543                         spin_unlock(&delayed_refs->lock);
2544                         locked_ref = NULL;
2545                         cond_resched();
2546                         count++;
2547                         continue;
2548                 }
2549
2550                 /*
2551                  * record the must insert reserved flag before we
2552                  * drop the spin lock.
2553                  */
2554                 must_insert_reserved = locked_ref->must_insert_reserved;
2555                 locked_ref->must_insert_reserved = 0;
2556
2557                 extent_op = locked_ref->extent_op;
2558                 locked_ref->extent_op = NULL;
2559
2560                 if (!ref) {
2561
2562
2563                         /* All delayed refs have been processed, Go ahead
2564                          * and send the head node to run_one_delayed_ref,
2565                          * so that any accounting fixes can happen
2566                          */
2567                         ref = &locked_ref->node;
2568
2569                         if (extent_op && must_insert_reserved) {
2570                                 btrfs_free_delayed_extent_op(extent_op);
2571                                 extent_op = NULL;
2572                         }
2573
2574                         if (extent_op) {
2575                                 spin_unlock(&locked_ref->lock);
2576                                 ret = run_delayed_extent_op(trans, root,
2577                                                             ref, extent_op);
2578                                 btrfs_free_delayed_extent_op(extent_op);
2579
2580                                 if (ret) {
2581                                         /*
2582                                          * Need to reset must_insert_reserved if
2583                                          * there was an error so the abort stuff
2584                                          * can cleanup the reserved space
2585                                          * properly.
2586                                          */
2587                                         if (must_insert_reserved)
2588                                                 locked_ref->must_insert_reserved = 1;
2589                                         locked_ref->processing = 0;
2590                                         btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2591                                         btrfs_delayed_ref_unlock(locked_ref);
2592                                         return ret;
2593                                 }
2594                                 continue;
2595                         }
2596
2597                         /*
2598                          * Need to drop our head ref lock and re-aqcuire the
2599                          * delayed ref lock and then re-check to make sure
2600                          * nobody got added.
2601                          */
2602                         spin_unlock(&locked_ref->lock);
2603                         spin_lock(&delayed_refs->lock);
2604                         spin_lock(&locked_ref->lock);
2605                         if (!list_empty(&locked_ref->ref_list) ||
2606                             locked_ref->extent_op) {
2607                                 spin_unlock(&locked_ref->lock);
2608                                 spin_unlock(&delayed_refs->lock);
2609                                 continue;
2610                         }
2611                         ref->in_tree = 0;
2612                         delayed_refs->num_heads--;
2613                         rb_erase(&locked_ref->href_node,
2614                                  &delayed_refs->href_root);
2615                         spin_unlock(&delayed_refs->lock);
2616                 } else {
2617                         actual_count++;
2618                         ref->in_tree = 0;
2619                         list_del(&ref->list);
2620                 }
2621                 atomic_dec(&delayed_refs->num_entries);
2622
2623                 if (!btrfs_delayed_ref_is_head(ref)) {
2624                         /*
2625                          * when we play the delayed ref, also correct the
2626                          * ref_mod on head
2627                          */
2628                         switch (ref->action) {
2629                         case BTRFS_ADD_DELAYED_REF:
2630                         case BTRFS_ADD_DELAYED_EXTENT:
2631                                 locked_ref->node.ref_mod -= ref->ref_mod;
2632                                 break;
2633                         case BTRFS_DROP_DELAYED_REF:
2634                                 locked_ref->node.ref_mod += ref->ref_mod;
2635                                 break;
2636                         default:
2637                                 WARN_ON(1);
2638                         }
2639                 }
2640                 spin_unlock(&locked_ref->lock);
2641
2642                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2643                                           must_insert_reserved);
2644
2645                 btrfs_free_delayed_extent_op(extent_op);
2646                 if (ret) {
2647                         locked_ref->processing = 0;
2648                         btrfs_delayed_ref_unlock(locked_ref);
2649                         btrfs_put_delayed_ref(ref);
2650                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d", ret);
2651                         return ret;
2652                 }
2653
2654                 /*
2655                  * If this node is a head, that means all the refs in this head
2656                  * have been dealt with, and we will pick the next head to deal
2657                  * with, so we must unlock the head and drop it from the cluster
2658                  * list before we release it.
2659                  */
2660                 if (btrfs_delayed_ref_is_head(ref)) {
2661                         if (locked_ref->is_data &&
2662                             locked_ref->total_ref_mod < 0) {
2663                                 spin_lock(&delayed_refs->lock);
2664                                 delayed_refs->pending_csums -= ref->num_bytes;
2665                                 spin_unlock(&delayed_refs->lock);
2666                         }
2667                         btrfs_delayed_ref_unlock(locked_ref);
2668                         locked_ref = NULL;
2669                 }
2670                 btrfs_put_delayed_ref(ref);
2671                 count++;
2672                 cond_resched();
2673         }
2674
2675         /*
2676          * We don't want to include ref heads since we can have empty ref heads
2677          * and those will drastically skew our runtime down since we just do
2678          * accounting, no actual extent tree updates.
2679          */
2680         if (actual_count > 0) {
2681                 u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2682                 u64 avg;
2683
2684                 /*
2685                  * We weigh the current average higher than our current runtime
2686                  * to avoid large swings in the average.
2687                  */
2688                 spin_lock(&delayed_refs->lock);
2689                 avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2690                 fs_info->avg_delayed_ref_runtime = avg >> 2;    /* div by 4 */
2691                 spin_unlock(&delayed_refs->lock);
2692         }
2693         return 0;
2694 }
2695
2696 #ifdef SCRAMBLE_DELAYED_REFS
2697 /*
2698  * Normally delayed refs get processed in ascending bytenr order. This
2699  * correlates in most cases to the order added. To expose dependencies on this
2700  * order, we start to process the tree in the middle instead of the beginning
2701  */
2702 static u64 find_middle(struct rb_root *root)
2703 {
2704         struct rb_node *n = root->rb_node;
2705         struct btrfs_delayed_ref_node *entry;
2706         int alt = 1;
2707         u64 middle;
2708         u64 first = 0, last = 0;
2709
2710         n = rb_first(root);
2711         if (n) {
2712                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2713                 first = entry->bytenr;
2714         }
2715         n = rb_last(root);
2716         if (n) {
2717                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2718                 last = entry->bytenr;
2719         }
2720         n = root->rb_node;
2721
2722         while (n) {
2723                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2724                 WARN_ON(!entry->in_tree);
2725
2726                 middle = entry->bytenr;
2727
2728                 if (alt)
2729                         n = n->rb_left;
2730                 else
2731                         n = n->rb_right;
2732
2733                 alt = 1 - alt;
2734         }
2735         return middle;
2736 }
2737 #endif
2738
2739 static inline u64 heads_to_leaves(struct btrfs_root *root, u64 heads)
2740 {
2741         u64 num_bytes;
2742
2743         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2744                              sizeof(struct btrfs_extent_inline_ref));
2745         if (!btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2746                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2747
2748         /*
2749          * We don't ever fill up leaves all the way so multiply by 2 just to be
2750          * closer to what we're really going to want to ouse.
2751          */
2752         return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(root));
2753 }
2754
2755 /*
2756  * Takes the number of bytes to be csumm'ed and figures out how many leaves it
2757  * would require to store the csums for that many bytes.
2758  */
2759 u64 btrfs_csum_bytes_to_leaves(struct btrfs_root *root, u64 csum_bytes)
2760 {
2761         u64 csum_size;
2762         u64 num_csums_per_leaf;
2763         u64 num_csums;
2764
2765         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
2766         num_csums_per_leaf = div64_u64(csum_size,
2767                         (u64)btrfs_super_csum_size(root->fs_info->super_copy));
2768         num_csums = div64_u64(csum_bytes, root->sectorsize);
2769         num_csums += num_csums_per_leaf - 1;
2770         num_csums = div64_u64(num_csums, num_csums_per_leaf);
2771         return num_csums;
2772 }
2773
2774 int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans,
2775                                        struct btrfs_root *root)
2776 {
2777         struct btrfs_block_rsv *global_rsv;
2778         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2779         u64 csum_bytes = trans->transaction->delayed_refs.pending_csums;
2780         u64 num_dirty_bgs = trans->transaction->num_dirty_bgs;
2781         u64 num_bytes, num_dirty_bgs_bytes;
2782         int ret = 0;
2783
2784         num_bytes = btrfs_calc_trans_metadata_size(root, 1);
2785         num_heads = heads_to_leaves(root, num_heads);
2786         if (num_heads > 1)
2787                 num_bytes += (num_heads - 1) * root->nodesize;
2788         num_bytes <<= 1;
2789         num_bytes += btrfs_csum_bytes_to_leaves(root, csum_bytes) * root->nodesize;
2790         num_dirty_bgs_bytes = btrfs_calc_trans_metadata_size(root,
2791                                                              num_dirty_bgs);
2792         global_rsv = &root->fs_info->global_block_rsv;
2793
2794         /*
2795          * If we can't allocate any more chunks lets make sure we have _lots_ of
2796          * wiggle room since running delayed refs can create more delayed refs.
2797          */
2798         if (global_rsv->space_info->full) {
2799                 num_dirty_bgs_bytes <<= 1;
2800                 num_bytes <<= 1;
2801         }
2802
2803         spin_lock(&global_rsv->lock);
2804         if (global_rsv->reserved <= num_bytes + num_dirty_bgs_bytes)
2805                 ret = 1;
2806         spin_unlock(&global_rsv->lock);
2807         return ret;
2808 }
2809
2810 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2811                                        struct btrfs_root *root)
2812 {
2813         struct btrfs_fs_info *fs_info = root->fs_info;
2814         u64 num_entries =
2815                 atomic_read(&trans->transaction->delayed_refs.num_entries);
2816         u64 avg_runtime;
2817         u64 val;
2818
2819         smp_mb();
2820         avg_runtime = fs_info->avg_delayed_ref_runtime;
2821         val = num_entries * avg_runtime;
2822         if (num_entries * avg_runtime >= NSEC_PER_SEC)
2823                 return 1;
2824         if (val >= NSEC_PER_SEC / 2)
2825                 return 2;
2826
2827         return btrfs_check_space_for_delayed_refs(trans, root);
2828 }
2829
2830 struct async_delayed_refs {
2831         struct btrfs_root *root;
2832         int count;
2833         int error;
2834         int sync;
2835         struct completion wait;
2836         struct btrfs_work work;
2837 };
2838
2839 static void delayed_ref_async_start(struct btrfs_work *work)
2840 {
2841         struct async_delayed_refs *async;
2842         struct btrfs_trans_handle *trans;
2843         int ret;
2844
2845         async = container_of(work, struct async_delayed_refs, work);
2846
2847         trans = btrfs_join_transaction(async->root);
2848         if (IS_ERR(trans)) {
2849                 async->error = PTR_ERR(trans);
2850                 goto done;
2851         }
2852
2853         /*
2854          * trans->sync means that when we call end_transaciton, we won't
2855          * wait on delayed refs
2856          */
2857         trans->sync = true;
2858         ret = btrfs_run_delayed_refs(trans, async->root, async->count);
2859         if (ret)
2860                 async->error = ret;
2861
2862         ret = btrfs_end_transaction(trans, async->root);
2863         if (ret && !async->error)
2864                 async->error = ret;
2865 done:
2866         if (async->sync)
2867                 complete(&async->wait);
2868         else
2869                 kfree(async);
2870 }
2871
2872 int btrfs_async_run_delayed_refs(struct btrfs_root *root,
2873                                  unsigned long count, int wait)
2874 {
2875         struct async_delayed_refs *async;
2876         int ret;
2877
2878         async = kmalloc(sizeof(*async), GFP_NOFS);
2879         if (!async)
2880                 return -ENOMEM;
2881
2882         async->root = root->fs_info->tree_root;
2883         async->count = count;
2884         async->error = 0;
2885         if (wait)
2886                 async->sync = 1;
2887         else
2888                 async->sync = 0;
2889         init_completion(&async->wait);
2890
2891         btrfs_init_work(&async->work, btrfs_extent_refs_helper,
2892                         delayed_ref_async_start, NULL, NULL);
2893
2894         btrfs_queue_work(root->fs_info->extent_workers, &async->work);
2895
2896         if (wait) {
2897                 wait_for_completion(&async->wait);
2898                 ret = async->error;
2899                 kfree(async);
2900                 return ret;
2901         }
2902         return 0;
2903 }
2904
2905 /*
2906  * this starts processing the delayed reference count updates and
2907  * extent insertions we have queued up so far.  count can be
2908  * 0, which means to process everything in the tree at the start
2909  * of the run (but not newly added entries), or it can be some target
2910  * number you'd like to process.
2911  *
2912  * Returns 0 on success or if called with an aborted transaction
2913  * Returns <0 on error and aborts the transaction
2914  */
2915 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2916                            struct btrfs_root *root, unsigned long count)
2917 {
2918         struct rb_node *node;
2919         struct btrfs_delayed_ref_root *delayed_refs;
2920         struct btrfs_delayed_ref_head *head;
2921         int ret;
2922         int run_all = count == (unsigned long)-1;
2923         bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
2924
2925         /* We'll clean this up in btrfs_cleanup_transaction */
2926         if (trans->aborted)
2927                 return 0;
2928
2929         if (root->fs_info->creating_free_space_tree)
2930                 return 0;
2931
2932         if (root == root->fs_info->extent_root)
2933                 root = root->fs_info->tree_root;
2934
2935         delayed_refs = &trans->transaction->delayed_refs;
2936         if (count == 0)
2937                 count = atomic_read(&delayed_refs->num_entries) * 2;
2938
2939 again:
2940 #ifdef SCRAMBLE_DELAYED_REFS
2941         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2942 #endif
2943         trans->can_flush_pending_bgs = false;
2944         ret = __btrfs_run_delayed_refs(trans, root, count);
2945         if (ret < 0) {
2946                 btrfs_abort_transaction(trans, root, ret);
2947                 return ret;
2948         }
2949
2950         if (run_all) {
2951                 if (!list_empty(&trans->new_bgs))
2952                         btrfs_create_pending_block_groups(trans, root);
2953
2954                 spin_lock(&delayed_refs->lock);
2955                 node = rb_first(&delayed_refs->href_root);
2956                 if (!node) {
2957                         spin_unlock(&delayed_refs->lock);
2958                         goto out;
2959                 }
2960                 count = (unsigned long)-1;
2961
2962                 while (node) {
2963                         head = rb_entry(node, struct btrfs_delayed_ref_head,
2964                                         href_node);
2965                         if (btrfs_delayed_ref_is_head(&head->node)) {
2966                                 struct btrfs_delayed_ref_node *ref;
2967
2968                                 ref = &head->node;
2969                                 atomic_inc(&ref->refs);
2970
2971                                 spin_unlock(&delayed_refs->lock);
2972                                 /*
2973                                  * Mutex was contended, block until it's
2974                                  * released and try again
2975                                  */
2976                                 mutex_lock(&head->mutex);
2977                                 mutex_unlock(&head->mutex);
2978
2979                                 btrfs_put_delayed_ref(ref);
2980                                 cond_resched();
2981                                 goto again;
2982                         } else {
2983                                 WARN_ON(1);
2984                         }
2985                         node = rb_next(node);
2986                 }
2987                 spin_unlock(&delayed_refs->lock);
2988                 cond_resched();
2989                 goto again;
2990         }
2991 out:
2992         assert_qgroups_uptodate(trans);
2993         trans->can_flush_pending_bgs = can_flush_pending_bgs;
2994         return 0;
2995 }
2996
2997 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2998                                 struct btrfs_root *root,
2999                                 u64 bytenr, u64 num_bytes, u64 flags,
3000                                 int level, int is_data)
3001 {
3002         struct btrfs_delayed_extent_op *extent_op;
3003         int ret;
3004
3005         extent_op = btrfs_alloc_delayed_extent_op();
3006         if (!extent_op)
3007                 return -ENOMEM;
3008
3009         extent_op->flags_to_set = flags;
3010         extent_op->update_flags = true;
3011         extent_op->update_key = false;
3012         extent_op->is_data = is_data ? true : false;
3013         extent_op->level = level;
3014
3015         ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
3016                                           num_bytes, extent_op);
3017         if (ret)
3018                 btrfs_free_delayed_extent_op(extent_op);
3019         return ret;
3020 }
3021
3022 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
3023                                       struct btrfs_root *root,
3024                                       struct btrfs_path *path,
3025                                       u64 objectid, u64 offset, u64 bytenr)
3026 {
3027         struct btrfs_delayed_ref_head *head;
3028         struct btrfs_delayed_ref_node *ref;
3029         struct btrfs_delayed_data_ref *data_ref;
3030         struct btrfs_delayed_ref_root *delayed_refs;
3031         int ret = 0;
3032
3033         delayed_refs = &trans->transaction->delayed_refs;
3034         spin_lock(&delayed_refs->lock);
3035         head = btrfs_find_delayed_ref_head(trans, bytenr);
3036         if (!head) {
3037                 spin_unlock(&delayed_refs->lock);
3038                 return 0;
3039         }
3040
3041         if (!mutex_trylock(&head->mutex)) {
3042                 atomic_inc(&head->node.refs);
3043                 spin_unlock(&delayed_refs->lock);
3044
3045                 btrfs_release_path(path);
3046
3047                 /*
3048                  * Mutex was contended, block until it's released and let
3049                  * caller try again
3050                  */
3051                 mutex_lock(&head->mutex);
3052                 mutex_unlock(&head->mutex);
3053                 btrfs_put_delayed_ref(&head->node);
3054                 return -EAGAIN;
3055         }
3056         spin_unlock(&delayed_refs->lock);
3057
3058         spin_lock(&head->lock);
3059         list_for_each_entry(ref, &head->ref_list, list) {
3060                 /* If it's a shared ref we know a cross reference exists */
3061                 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
3062                         ret = 1;
3063                         break;
3064                 }
3065
3066                 data_ref = btrfs_delayed_node_to_data_ref(ref);
3067
3068                 /*
3069                  * If our ref doesn't match the one we're currently looking at
3070                  * then we have a cross reference.
3071                  */
3072                 if (data_ref->root != root->root_key.objectid ||
3073                     data_ref->objectid != objectid ||
3074                     data_ref->offset != offset) {
3075                         ret = 1;
3076                         break;
3077                 }
3078         }
3079         spin_unlock(&head->lock);
3080         mutex_unlock(&head->mutex);
3081         return ret;
3082 }
3083
3084 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
3085                                         struct btrfs_root *root,
3086                                         struct btrfs_path *path,
3087                                         u64 objectid, u64 offset, u64 bytenr)
3088 {
3089         struct btrfs_root *extent_root = root->fs_info->extent_root;
3090         struct extent_buffer *leaf;
3091         struct btrfs_extent_data_ref *ref;
3092         struct btrfs_extent_inline_ref *iref;
3093         struct btrfs_extent_item *ei;
3094         struct btrfs_key key;
3095         u32 item_size;
3096         int ret;
3097
3098         key.objectid = bytenr;
3099         key.offset = (u64)-1;
3100         key.type = BTRFS_EXTENT_ITEM_KEY;
3101
3102         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
3103         if (ret < 0)
3104                 goto out;
3105         BUG_ON(ret == 0); /* Corruption */
3106
3107         ret = -ENOENT;
3108         if (path->slots[0] == 0)
3109                 goto out;
3110
3111         path->slots[0]--;
3112         leaf = path->nodes[0];
3113         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3114
3115         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
3116                 goto out;
3117
3118         ret = 1;
3119         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
3120 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3121         if (item_size < sizeof(*ei)) {
3122                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3123                 goto out;
3124         }
3125 #endif
3126         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
3127
3128         if (item_size != sizeof(*ei) +
3129             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
3130                 goto out;
3131
3132         if (btrfs_extent_generation(leaf, ei) <=
3133             btrfs_root_last_snapshot(&root->root_item))
3134                 goto out;
3135
3136         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
3137         if (btrfs_extent_inline_ref_type(leaf, iref) !=
3138             BTRFS_EXTENT_DATA_REF_KEY)
3139                 goto out;
3140
3141         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
3142         if (btrfs_extent_refs(leaf, ei) !=
3143             btrfs_extent_data_ref_count(leaf, ref) ||
3144             btrfs_extent_data_ref_root(leaf, ref) !=
3145             root->root_key.objectid ||
3146             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
3147             btrfs_extent_data_ref_offset(leaf, ref) != offset)
3148                 goto out;
3149
3150         ret = 0;
3151 out:
3152         return ret;
3153 }
3154
3155 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
3156                           struct btrfs_root *root,
3157                           u64 objectid, u64 offset, u64 bytenr)
3158 {
3159         struct btrfs_path *path;
3160         int ret;
3161         int ret2;
3162
3163         path = btrfs_alloc_path();
3164         if (!path)
3165                 return -ENOENT;
3166
3167         do {
3168                 ret = check_committed_ref(trans, root, path, objectid,
3169                                           offset, bytenr);
3170                 if (ret && ret != -ENOENT)
3171                         goto out;
3172
3173                 ret2 = check_delayed_ref(trans, root, path, objectid,
3174                                          offset, bytenr);
3175         } while (ret2 == -EAGAIN);
3176
3177         if (ret2 && ret2 != -ENOENT) {
3178                 ret = ret2;
3179                 goto out;
3180         }
3181
3182         if (ret != -ENOENT || ret2 != -ENOENT)
3183                 ret = 0;
3184 out:
3185         btrfs_free_path(path);
3186         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3187                 WARN_ON(ret > 0);
3188         return ret;
3189 }
3190
3191 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3192                            struct btrfs_root *root,
3193                            struct extent_buffer *buf,
3194                            int full_backref, int inc)
3195 {
3196         u64 bytenr;
3197         u64 num_bytes;
3198         u64 parent;
3199         u64 ref_root;
3200         u32 nritems;
3201         struct btrfs_key key;
3202         struct btrfs_file_extent_item *fi;
3203         int i;
3204         int level;
3205         int ret = 0;
3206         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
3207                             u64, u64, u64, u64, u64, u64);
3208
3209
3210         if (btrfs_test_is_dummy_root(root))
3211                 return 0;
3212
3213         ref_root = btrfs_header_owner(buf);
3214         nritems = btrfs_header_nritems(buf);
3215         level = btrfs_header_level(buf);
3216
3217         if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
3218                 return 0;
3219
3220         if (inc)
3221                 process_func = btrfs_inc_extent_ref;
3222         else
3223                 process_func = btrfs_free_extent;
3224
3225         if (full_backref)
3226                 parent = buf->start;
3227         else
3228                 parent = 0;
3229
3230         for (i = 0; i < nritems; i++) {
3231                 if (level == 0) {
3232                         btrfs_item_key_to_cpu(buf, &key, i);
3233                         if (key.type != BTRFS_EXTENT_DATA_KEY)
3234                                 continue;
3235                         fi = btrfs_item_ptr(buf, i,
3236                                             struct btrfs_file_extent_item);
3237                         if (btrfs_file_extent_type(buf, fi) ==
3238                             BTRFS_FILE_EXTENT_INLINE)
3239                                 continue;
3240                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3241                         if (bytenr == 0)
3242                                 continue;
3243
3244                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3245                         key.offset -= btrfs_file_extent_offset(buf, fi);
3246                         ret = process_func(trans, root, bytenr, num_bytes,
3247                                            parent, ref_root, key.objectid,
3248                                            key.offset);
3249                         if (ret)
3250                                 goto fail;
3251                 } else {
3252                         bytenr = btrfs_node_blockptr(buf, i);
3253                         num_bytes = root->nodesize;
3254                         ret = process_func(trans, root, bytenr, num_bytes,
3255                                            parent, ref_root, level - 1, 0);
3256                         if (ret)
3257                                 goto fail;
3258                 }
3259         }
3260         return 0;
3261 fail:
3262         return ret;
3263 }
3264
3265 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3266                   struct extent_buffer *buf, int full_backref)
3267 {
3268         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
3269 }
3270
3271 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3272                   struct extent_buffer *buf, int full_backref)
3273 {
3274         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
3275 }
3276
3277 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3278                                  struct btrfs_root *root,
3279                                  struct btrfs_path *path,
3280                                  struct btrfs_block_group_cache *cache)
3281 {
3282         int ret;
3283         struct btrfs_root *extent_root = root->fs_info->extent_root;
3284         unsigned long bi;
3285         struct extent_buffer *leaf;
3286
3287         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3288         if (ret) {
3289                 if (ret > 0)
3290                         ret = -ENOENT;
3291                 goto fail;
3292         }
3293
3294         leaf = path->nodes[0];
3295         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3296         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3297         btrfs_mark_buffer_dirty(leaf);
3298 fail:
3299         btrfs_release_path(path);
3300         return ret;
3301
3302 }
3303
3304 static struct btrfs_block_group_cache *
3305 next_block_group(struct btrfs_root *root,
3306                  struct btrfs_block_group_cache *cache)
3307 {
3308         struct rb_node *node;
3309
3310         spin_lock(&root->fs_info->block_group_cache_lock);
3311
3312         /* If our block group was removed, we need a full search. */
3313         if (RB_EMPTY_NODE(&cache->cache_node)) {
3314                 const u64 next_bytenr = cache->key.objectid + cache->key.offset;
3315
3316                 spin_unlock(&root->fs_info->block_group_cache_lock);
3317                 btrfs_put_block_group(cache);
3318                 cache = btrfs_lookup_first_block_group(root->fs_info,
3319                                                        next_bytenr);
3320                 return cache;
3321         }
3322         node = rb_next(&cache->cache_node);
3323         btrfs_put_block_group(cache);
3324         if (node) {
3325                 cache = rb_entry(node, struct btrfs_block_group_cache,
3326                                  cache_node);
3327                 btrfs_get_block_group(cache);
3328         } else
3329                 cache = NULL;
3330         spin_unlock(&root->fs_info->block_group_cache_lock);
3331         return cache;
3332 }
3333
3334 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3335                             struct btrfs_trans_handle *trans,
3336                             struct btrfs_path *path)
3337 {
3338         struct btrfs_root *root = block_group->fs_info->tree_root;
3339         struct inode *inode = NULL;
3340         u64 alloc_hint = 0;
3341         int dcs = BTRFS_DC_ERROR;
3342         u64 num_pages = 0;
3343         int retries = 0;
3344         int ret = 0;
3345
3346         /*
3347          * If this block group is smaller than 100 megs don't bother caching the
3348          * block group.
3349          */
3350         if (block_group->key.offset < (100 * SZ_1M)) {
3351                 spin_lock(&block_group->lock);
3352                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3353                 spin_unlock(&block_group->lock);
3354                 return 0;
3355         }
3356
3357         if (trans->aborted)
3358                 return 0;
3359 again:
3360         inode = lookup_free_space_inode(root, block_group, path);
3361         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3362                 ret = PTR_ERR(inode);
3363                 btrfs_release_path(path);
3364                 goto out;
3365         }
3366
3367         if (IS_ERR(inode)) {
3368                 BUG_ON(retries);
3369                 retries++;
3370
3371                 if (block_group->ro)
3372                         goto out_free;
3373
3374                 ret = create_free_space_inode(root, trans, block_group, path);
3375                 if (ret)
3376                         goto out_free;
3377                 goto again;
3378         }
3379
3380         /* We've already setup this transaction, go ahead and exit */
3381         if (block_group->cache_generation == trans->transid &&
3382             i_size_read(inode)) {
3383                 dcs = BTRFS_DC_SETUP;
3384                 goto out_put;
3385         }
3386
3387         /*
3388          * We want to set the generation to 0, that way if anything goes wrong
3389          * from here on out we know not to trust this cache when we load up next
3390          * time.
3391          */
3392         BTRFS_I(inode)->generation = 0;
3393         ret = btrfs_update_inode(trans, root, inode);
3394         if (ret) {
3395                 /*
3396                  * So theoretically we could recover from this, simply set the
3397                  * super cache generation to 0 so we know to invalidate the
3398                  * cache, but then we'd have to keep track of the block groups
3399                  * that fail this way so we know we _have_ to reset this cache
3400                  * before the next commit or risk reading stale cache.  So to
3401                  * limit our exposure to horrible edge cases lets just abort the
3402                  * transaction, this only happens in really bad situations
3403                  * anyway.
3404                  */
3405                 btrfs_abort_transaction(trans, root, ret);
3406                 goto out_put;
3407         }
3408         WARN_ON(ret);
3409
3410         if (i_size_read(inode) > 0) {
3411                 ret = btrfs_check_trunc_cache_free_space(root,
3412                                         &root->fs_info->global_block_rsv);
3413                 if (ret)
3414                         goto out_put;
3415
3416                 ret = btrfs_truncate_free_space_cache(root, trans, NULL, inode);
3417                 if (ret)
3418                         goto out_put;
3419         }
3420
3421         spin_lock(&block_group->lock);
3422         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3423             !btrfs_test_opt(root, SPACE_CACHE)) {
3424                 /*
3425                  * don't bother trying to write stuff out _if_
3426                  * a) we're not cached,
3427                  * b) we're with nospace_cache mount option.
3428                  */
3429                 dcs = BTRFS_DC_WRITTEN;
3430                 spin_unlock(&block_group->lock);
3431                 goto out_put;
3432         }
3433         spin_unlock(&block_group->lock);
3434
3435         /*
3436          * We hit an ENOSPC when setting up the cache in this transaction, just
3437          * skip doing the setup, we've already cleared the cache so we're safe.
3438          */
3439         if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
3440                 ret = -ENOSPC;
3441                 goto out_put;
3442         }
3443
3444         /*
3445          * Try to preallocate enough space based on how big the block group is.
3446          * Keep in mind this has to include any pinned space which could end up
3447          * taking up quite a bit since it's not folded into the other space
3448          * cache.
3449          */
3450         num_pages = div_u64(block_group->key.offset, SZ_256M);
3451         if (!num_pages)
3452                 num_pages = 1;
3453
3454         num_pages *= 16;
3455         num_pages *= PAGE_CACHE_SIZE;
3456
3457         ret = btrfs_check_data_free_space(inode, 0, num_pages);
3458         if (ret)
3459                 goto out_put;
3460
3461         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3462                                               num_pages, num_pages,
3463                                               &alloc_hint);
3464         /*
3465          * Our cache requires contiguous chunks so that we don't modify a bunch
3466          * of metadata or split extents when writing the cache out, which means
3467          * we can enospc if we are heavily fragmented in addition to just normal
3468          * out of space conditions.  So if we hit this just skip setting up any
3469          * other block groups for this transaction, maybe we'll unpin enough
3470          * space the next time around.
3471          */
3472         if (!ret)
3473                 dcs = BTRFS_DC_SETUP;
3474         else if (ret == -ENOSPC)
3475                 set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
3476         btrfs_free_reserved_data_space(inode, 0, num_pages);
3477
3478 out_put:
3479         iput(inode);
3480 out_free:
3481         btrfs_release_path(path);
3482 out:
3483         spin_lock(&block_group->lock);
3484         if (!ret && dcs == BTRFS_DC_SETUP)
3485                 block_group->cache_generation = trans->transid;
3486         block_group->disk_cache_state = dcs;
3487         spin_unlock(&block_group->lock);
3488
3489         return ret;
3490 }
3491
3492 int btrfs_setup_space_cache(struct btrfs_trans_handle *trans,
3493                             struct btrfs_root *root)
3494 {
3495         struct btrfs_block_group_cache *cache, *tmp;
3496         struct btrfs_transaction *cur_trans = trans->transaction;
3497         struct btrfs_path *path;
3498
3499         if (list_empty(&cur_trans->dirty_bgs) ||
3500             !btrfs_test_opt(root, SPACE_CACHE))
3501                 return 0;
3502
3503         path = btrfs_alloc_path();
3504         if (!path)
3505                 return -ENOMEM;
3506
3507         /* Could add new block groups, use _safe just in case */
3508         list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
3509                                  dirty_list) {
3510                 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3511                         cache_save_setup(cache, trans, path);
3512         }
3513
3514         btrfs_free_path(path);
3515         return 0;
3516 }
3517
3518 /*
3519  * transaction commit does final block group cache writeback during a
3520  * critical section where nothing is allowed to change the FS.  This is
3521  * required in order for the cache to actually match the block group,
3522  * but can introduce a lot of latency into the commit.
3523  *
3524  * So, btrfs_start_dirty_block_groups is here to kick off block group
3525  * cache IO.  There's a chance we'll have to redo some of it if the
3526  * block group changes again during the commit, but it greatly reduces
3527  * the commit latency by getting rid of the easy block groups while
3528  * we're still allowing others to join the commit.
3529  */
3530 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans,
3531                                    struct btrfs_root *root)
3532 {
3533         struct btrfs_block_group_cache *cache;
3534         struct btrfs_transaction *cur_trans = trans->transaction;
3535         int ret = 0;
3536         int should_put;
3537         struct btrfs_path *path = NULL;
3538         LIST_HEAD(dirty);
3539         struct list_head *io = &cur_trans->io_bgs;
3540         int num_started = 0;
3541         int loops = 0;
3542
3543         spin_lock(&cur_trans->dirty_bgs_lock);
3544         if (list_empty(&cur_trans->dirty_bgs)) {
3545                 spin_unlock(&cur_trans->dirty_bgs_lock);
3546                 return 0;
3547         }
3548         list_splice_init(&cur_trans->dirty_bgs, &dirty);
3549         spin_unlock(&cur_trans->dirty_bgs_lock);
3550
3551 again:
3552         /*
3553          * make sure all the block groups on our dirty list actually
3554          * exist
3555          */
3556         btrfs_create_pending_block_groups(trans, root);
3557
3558         if (!path) {
3559                 path = btrfs_alloc_path();
3560                 if (!path)
3561                         return -ENOMEM;
3562         }
3563
3564         /*
3565          * cache_write_mutex is here only to save us from balance or automatic
3566          * removal of empty block groups deleting this block group while we are
3567          * writing out the cache
3568          */
3569         mutex_lock(&trans->transaction->cache_write_mutex);
3570         while (!list_empty(&dirty)) {
3571                 cache = list_first_entry(&dirty,
3572                                          struct btrfs_block_group_cache,
3573                                          dirty_list);
3574                 /*
3575                  * this can happen if something re-dirties a block
3576                  * group that is already under IO.  Just wait for it to
3577                  * finish and then do it all again
3578                  */
3579                 if (!list_empty(&cache->io_list)) {
3580                         list_del_init(&cache->io_list);
3581                         btrfs_wait_cache_io(root, trans, cache,
3582                                             &cache->io_ctl, path,
3583                                             cache->key.objectid);
3584                         btrfs_put_block_group(cache);
3585                 }
3586
3587
3588                 /*
3589                  * btrfs_wait_cache_io uses the cache->dirty_list to decide
3590                  * if it should update the cache_state.  Don't delete
3591                  * until after we wait.
3592                  *
3593                  * Since we're not running in the commit critical section
3594                  * we need the dirty_bgs_lock to protect from update_block_group
3595                  */
3596                 spin_lock(&cur_trans->dirty_bgs_lock);
3597                 list_del_init(&cache->dirty_list);
3598                 spin_unlock(&cur_trans->dirty_bgs_lock);
3599
3600                 should_put = 1;
3601
3602                 cache_save_setup(cache, trans, path);
3603
3604                 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
3605                         cache->io_ctl.inode = NULL;
3606                         ret = btrfs_write_out_cache(root, trans, cache, path);
3607                         if (ret == 0 && cache->io_ctl.inode) {
3608                                 num_started++;
3609                                 should_put = 0;
3610
3611                                 /*
3612                                  * the cache_write_mutex is protecting
3613                                  * the io_list
3614                                  */
3615                                 list_add_tail(&cache->io_list, io);
3616                         } else {
3617                                 /*
3618                                  * if we failed to write the cache, the
3619                                  * generation will be bad and life goes on
3620                                  */
3621                                 ret = 0;
3622                         }
3623                 }
3624                 if (!ret) {
3625                         ret = write_one_cache_group(trans, root, path, cache);
3626                         /*
3627                          * Our block group might still be attached to the list
3628                          * of new block groups in the transaction handle of some
3629                          * other task (struct btrfs_trans_handle->new_bgs). This
3630                          * means its block group item isn't yet in the extent
3631                          * tree. If this happens ignore the error, as we will
3632                          * try again later in the critical section of the
3633                          * transaction commit.
3634                          */
3635                         if (ret == -ENOENT) {
3636                                 ret = 0;
3637                                 spin_lock(&cur_trans->dirty_bgs_lock);
3638                                 if (list_empty(&cache->dirty_list)) {
3639                                         list_add_tail(&cache->dirty_list,
3640                                                       &cur_trans->dirty_bgs);
3641                                         btrfs_get_block_group(cache);
3642                                 }
3643                                 spin_unlock(&cur_trans->dirty_bgs_lock);
3644                         } else if (ret) {
3645                                 btrfs_abort_transaction(trans, root, ret);
3646                         }
3647                 }
3648
3649                 /* if its not on the io list, we need to put the block group */
3650                 if (should_put)
3651                         btrfs_put_block_group(cache);
3652
3653                 if (ret)
3654                         break;
3655
3656                 /*
3657                  * Avoid blocking other tasks for too long. It might even save
3658                  * us from writing caches for block groups that are going to be
3659                  * removed.
3660                  */
3661                 mutex_unlock(&trans->transaction->cache_write_mutex);
3662                 mutex_lock(&trans->transaction->cache_write_mutex);
3663         }
3664         mutex_unlock(&trans->transaction->cache_write_mutex);
3665
3666         /*
3667          * go through delayed refs for all the stuff we've just kicked off
3668          * and then loop back (just once)
3669          */
3670         ret = btrfs_run_delayed_refs(trans, root, 0);
3671         if (!ret && loops == 0) {
3672                 loops++;
3673                 spin_lock(&cur_trans->dirty_bgs_lock);
3674                 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3675                 /*
3676                  * dirty_bgs_lock protects us from concurrent block group
3677                  * deletes too (not just cache_write_mutex).
3678                  */
3679                 if (!list_empty(&dirty)) {
3680                         spin_unlock(&cur_trans->dirty_bgs_lock);
3681                         goto again;
3682                 }
3683                 spin_unlock(&cur_trans->dirty_bgs_lock);
3684         }
3685
3686         btrfs_free_path(path);
3687         return ret;
3688 }
3689
3690 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3691                                    struct btrfs_root *root)
3692 {
3693         struct btrfs_block_group_cache *cache;
3694         struct btrfs_transaction *cur_trans = trans->transaction;
3695         int ret = 0;
3696         int should_put;
3697         struct btrfs_path *path;
3698         struct list_head *io = &cur_trans->io_bgs;
3699         int num_started = 0;
3700
3701         path = btrfs_alloc_path();
3702         if (!path)
3703                 return -ENOMEM;
3704
3705         /*
3706          * Even though we are in the critical section of the transaction commit,
3707          * we can still have concurrent tasks adding elements to this
3708          * transaction's list of dirty block groups. These tasks correspond to
3709          * endio free space workers started when writeback finishes for a
3710          * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
3711          * allocate new block groups as a result of COWing nodes of the root
3712          * tree when updating the free space inode. The writeback for the space
3713          * caches is triggered by an earlier call to
3714          * btrfs_start_dirty_block_groups() and iterations of the following
3715          * loop.
3716          * Also we want to do the cache_save_setup first and then run the
3717          * delayed refs to make sure we have the best chance at doing this all
3718          * in one shot.
3719          */
3720         spin_lock(&cur_trans->dirty_bgs_lock);
3721         while (!list_empty(&cur_trans->dirty_bgs)) {
3722                 cache = list_first_entry(&cur_trans->dirty_bgs,
3723                                          struct btrfs_block_group_cache,
3724                                          dirty_list);
3725
3726                 /*
3727                  * this can happen if cache_save_setup re-dirties a block
3728                  * group that is already under IO.  Just wait for it to
3729                  * finish and then do it all again
3730                  */
3731                 if (!list_empty(&cache->io_list)) {
3732                         spin_unlock(&cur_trans->dirty_bgs_lock);
3733                         list_del_init(&cache->io_list);
3734                         btrfs_wait_cache_io(root, trans, cache,
3735                                             &cache->io_ctl, path,
3736                                             cache->key.objectid);
3737                         btrfs_put_block_group(cache);
3738                         spin_lock(&cur_trans->dirty_bgs_lock);
3739                 }
3740
3741                 /*
3742                  * don't remove from the dirty list until after we've waited
3743                  * on any pending IO
3744                  */
3745                 list_del_init(&cache->dirty_list);
3746                 spin_unlock(&cur_trans->dirty_bgs_lock);
3747                 should_put = 1;
3748
3749                 cache_save_setup(cache, trans, path);
3750
3751                 if (!ret)
3752                         ret = btrfs_run_delayed_refs(trans, root, (unsigned long) -1);
3753
3754                 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
3755                         cache->io_ctl.inode = NULL;
3756                         ret = btrfs_write_out_cache(root, trans, cache, path);
3757                         if (ret == 0 && cache->io_ctl.inode) {
3758                                 num_started++;
3759                                 should_put = 0;
3760                                 list_add_tail(&cache->io_list, io);
3761                         } else {
3762                                 /*
3763                                  * if we failed to write the cache, the
3764                                  * generation will be bad and life goes on
3765                                  */
3766                                 ret = 0;
3767                         }
3768                 }
3769                 if (!ret) {
3770                         ret = write_one_cache_group(trans, root, path, cache);
3771                         /*
3772                          * One of the free space endio workers might have
3773                          * created a new block group while updating a free space
3774                          * cache's inode (at inode.c:btrfs_finish_ordered_io())
3775                          * and hasn't released its transaction handle yet, in
3776                          * which case the new block group is still attached to
3777                          * its transaction handle and its creation has not
3778                          * finished yet (no block group item in the extent tree
3779                          * yet, etc). If this is the case, wait for all free
3780                          * space endio workers to finish and retry. This is a
3781                          * a very rare case so no need for a more efficient and
3782                          * complex approach.
3783                          */
3784                         if (ret == -ENOENT) {
3785                                 wait_event(cur_trans->writer_wait,
3786                                    atomic_read(&cur_trans->num_writers) == 1);
3787                                 ret = write_one_cache_group(trans, root, path,
3788                                                             cache);
3789                         }
3790                         if (ret)
3791                                 btrfs_abort_transaction(trans, root, ret);
3792                 }
3793
3794                 /* if its not on the io list, we need to put the block group */
3795                 if (should_put)
3796                         btrfs_put_block_group(cache);
3797                 spin_lock(&cur_trans->dirty_bgs_lock);
3798         }
3799         spin_unlock(&cur_trans->dirty_bgs_lock);
3800
3801         while (!list_empty(io)) {
3802                 cache = list_first_entry(io, struct btrfs_block_group_cache,
3803                                          io_list);
3804                 list_del_init(&cache->io_list);
3805                 btrfs_wait_cache_io(root, trans, cache,
3806                                     &cache->io_ctl, path, cache->key.objectid);
3807                 btrfs_put_block_group(cache);
3808         }
3809
3810         btrfs_free_path(path);
3811         return ret;
3812 }
3813
3814 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3815 {
3816         struct btrfs_block_group_cache *block_group;
3817         int readonly = 0;
3818
3819         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3820         if (!block_group || block_group->ro)
3821                 readonly = 1;
3822         if (block_group)
3823                 btrfs_put_block_group(block_group);
3824         return readonly;
3825 }
3826
3827 static const char *alloc_name(u64 flags)
3828 {
3829         switch (flags) {
3830         case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
3831                 return "mixed";
3832         case BTRFS_BLOCK_GROUP_METADATA:
3833                 return "metadata";
3834         case BTRFS_BLOCK_GROUP_DATA:
3835                 return "data";
3836         case BTRFS_BLOCK_GROUP_SYSTEM:
3837                 return "system";
3838         default:
3839                 WARN_ON(1);
3840                 return "invalid-combination";
3841         };
3842 }
3843
3844 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3845                              u64 total_bytes, u64 bytes_used,
3846                              struct btrfs_space_info **space_info)
3847 {
3848         struct btrfs_space_info *found;
3849         int i;
3850         int factor;
3851         int ret;
3852
3853         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3854                      BTRFS_BLOCK_GROUP_RAID10))
3855                 factor = 2;
3856         else
3857                 factor = 1;
3858
3859         found = __find_space_info(info, flags);
3860         if (found) {
3861                 spin_lock(&found->lock);
3862                 found->total_bytes += total_bytes;
3863                 found->disk_total += total_bytes * factor;
3864                 found->bytes_used += bytes_used;
3865                 found->disk_used += bytes_used * factor;
3866                 if (total_bytes > 0)
3867                         found->full = 0;
3868                 spin_unlock(&found->lock);
3869                 *space_info = found;
3870                 return 0;
3871         }
3872         found = kzalloc(sizeof(*found), GFP_NOFS);
3873         if (!found)
3874                 return -ENOMEM;
3875
3876         ret = percpu_counter_init(&found->total_bytes_pinned, 0, GFP_KERNEL);
3877         if (ret) {
3878                 kfree(found);
3879                 return ret;
3880         }
3881
3882         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3883                 INIT_LIST_HEAD(&found->block_groups[i]);
3884         init_rwsem(&found->groups_sem);
3885         spin_lock_init(&found->lock);
3886         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3887         found->total_bytes = total_bytes;
3888         found->disk_total = total_bytes * factor;
3889         found->bytes_used = bytes_used;
3890         found->disk_used = bytes_used * factor;
3891         found->bytes_pinned = 0;
3892         found->bytes_reserved = 0;
3893         found->bytes_readonly = 0;
3894         found->bytes_may_use = 0;
3895         found->full = 0;
3896         found->max_extent_size = 0;
3897         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3898         found->chunk_alloc = 0;
3899         found->flush = 0;
3900         init_waitqueue_head(&found->wait);
3901         INIT_LIST_HEAD(&found->ro_bgs);
3902
3903         ret = kobject_init_and_add(&found->kobj, &space_info_ktype,
3904                                     info->space_info_kobj, "%s",
3905                                     alloc_name(found->flags));
3906         if (ret) {
3907                 kfree(found);
3908                 return ret;
3909         }
3910
3911         *space_info = found;
3912         list_add_rcu(&found->list, &info->space_info);
3913         if (flags & BTRFS_BLOCK_GROUP_DATA)
3914                 info->data_sinfo = found;
3915
3916         return ret;
3917 }
3918
3919 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3920 {
3921         u64 extra_flags = chunk_to_extended(flags) &
3922                                 BTRFS_EXTENDED_PROFILE_MASK;
3923
3924         write_seqlock(&fs_info->profiles_lock);
3925         if (flags & BTRFS_BLOCK_GROUP_DATA)
3926                 fs_info->avail_data_alloc_bits |= extra_flags;
3927         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3928                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3929         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3930                 fs_info->avail_system_alloc_bits |= extra_flags;
3931         write_sequnlock(&fs_info->profiles_lock);
3932 }
3933
3934 /*
3935  * returns target flags in extended format or 0 if restripe for this
3936  * chunk_type is not in progress
3937  *
3938  * should be called with either volume_mutex or balance_lock held
3939  */
3940 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
3941 {
3942         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3943         u64 target = 0;
3944
3945         if (!bctl)
3946                 return 0;
3947
3948         if (flags & BTRFS_BLOCK_GROUP_DATA &&
3949             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3950                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3951         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
3952                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3953                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3954         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
3955                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3956                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3957         }
3958
3959         return target;
3960 }
3961
3962 /*
3963  * @flags: available profiles in extended format (see ctree.h)
3964  *
3965  * Returns reduced profile in chunk format.  If profile changing is in
3966  * progress (either running or paused) picks the target profile (if it's
3967  * already available), otherwise falls back to plain reducing.
3968  */
3969 static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3970 {
3971         u64 num_devices = root->fs_info->fs_devices->rw_devices;
3972         u64 target;
3973         u64 raid_type;
3974         u64 allowed = 0;
3975
3976         /*
3977          * see if restripe for this chunk_type is in progress, if so
3978          * try to reduce to the target profile
3979          */
3980         spin_lock(&root->fs_info->balance_lock);
3981         target = get_restripe_target(root->fs_info, flags);
3982         if (target) {
3983                 /* pick target profile only if it's already available */
3984                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
3985                         spin_unlock(&root->fs_info->balance_lock);
3986                         return extended_to_chunk(target);
3987                 }
3988         }
3989         spin_unlock(&root->fs_info->balance_lock);
3990
3991         /* First, mask out the RAID levels which aren't possible */
3992         for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
3993                 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
3994                         allowed |= btrfs_raid_group[raid_type];
3995         }
3996         allowed &= flags;
3997
3998         if (allowed & BTRFS_BLOCK_GROUP_RAID6)
3999                 allowed = BTRFS_BLOCK_GROUP_RAID6;
4000         else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
4001                 allowed = BTRFS_BLOCK_GROUP_RAID5;
4002         else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
4003                 allowed = BTRFS_BLOCK_GROUP_RAID10;
4004         else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
4005                 allowed = BTRFS_BLOCK_GROUP_RAID1;
4006         else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
4007                 allowed = BTRFS_BLOCK_GROUP_RAID0;
4008
4009         flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
4010
4011         return extended_to_chunk(flags | allowed);
4012 }
4013
4014 static u64 get_alloc_profile(struct btrfs_root *root, u64 orig_flags)
4015 {
4016         unsigned seq;
4017         u64 flags;
4018
4019         do {
4020                 flags = orig_flags;
4021                 seq = read_seqbegin(&root->fs_info->profiles_lock);
4022
4023                 if (flags & BTRFS_BLOCK_GROUP_DATA)
4024                         flags |= root->fs_info->avail_data_alloc_bits;
4025                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4026                         flags |= root->fs_info->avail_system_alloc_bits;
4027                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
4028                         flags |= root->fs_info->avail_metadata_alloc_bits;
4029         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
4030
4031         return btrfs_reduce_alloc_profile(root, flags);
4032 }
4033
4034 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
4035 {
4036         u64 flags;
4037         u64 ret;
4038
4039         if (data)
4040                 flags = BTRFS_BLOCK_GROUP_DATA;
4041         else if (root == root->fs_info->chunk_root)
4042                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
4043         else
4044                 flags = BTRFS_BLOCK_GROUP_METADATA;
4045
4046         ret = get_alloc_profile(root, flags);
4047         return ret;
4048 }
4049
4050 int btrfs_alloc_data_chunk_ondemand(struct inode *inode, u64 bytes)
4051 {
4052         struct btrfs_space_info *data_sinfo;
4053         struct btrfs_root *root = BTRFS_I(inode)->root;
4054         struct btrfs_fs_info *fs_info = root->fs_info;
4055         u64 used;
4056         int ret = 0;
4057         int need_commit = 2;
4058         int have_pinned_space;
4059
4060         /* make sure bytes are sectorsize aligned */
4061         bytes = ALIGN(bytes, root->sectorsize);
4062
4063         if (btrfs_is_free_space_inode(inode)) {
4064                 need_commit = 0;
4065                 ASSERT(current->journal_info);
4066         }
4067
4068         data_sinfo = fs_info->data_sinfo;
4069         if (!data_sinfo)
4070                 goto alloc;
4071
4072 again:
4073         /* make sure we have enough space to handle the data first */
4074         spin_lock(&data_sinfo->lock);
4075         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
4076                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
4077                 data_sinfo->bytes_may_use;
4078
4079         if (used + bytes > data_sinfo->total_bytes) {
4080                 struct btrfs_trans_handle *trans;
4081
4082                 /*
4083                  * if we don't have enough free bytes in this space then we need
4084                  * to alloc a new chunk.
4085                  */
4086                 if (!data_sinfo->full) {
4087                         u64 alloc_target;
4088
4089                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
4090                         spin_unlock(&data_sinfo->lock);
4091 alloc:
4092                         alloc_target = btrfs_get_alloc_profile(root, 1);
4093                         /*
4094                          * It is ugly that we don't call nolock join
4095                          * transaction for the free space inode case here.
4096                          * But it is safe because we only do the data space
4097                          * reservation for the free space cache in the
4098                          * transaction context, the common join transaction
4099                          * just increase the counter of the current transaction
4100                          * handler, doesn't try to acquire the trans_lock of
4101                          * the fs.
4102                          */
4103                         trans = btrfs_join_transaction(root);
4104                         if (IS_ERR(trans))
4105                                 return PTR_ERR(trans);
4106
4107                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4108                                              alloc_target,
4109                                              CHUNK_ALLOC_NO_FORCE);
4110                         btrfs_end_transaction(trans, root);
4111                         if (ret < 0) {
4112                                 if (ret != -ENOSPC)
4113                                         return ret;
4114                                 else {
4115                                         have_pinned_space = 1;
4116                                         goto commit_trans;
4117                                 }
4118                         }
4119
4120                         if (!data_sinfo)
4121                                 data_sinfo = fs_info->data_sinfo;
4122
4123                         goto again;
4124                 }
4125
4126                 /*
4127                  * If we don't have enough pinned space to deal with this
4128                  * allocation, and no removed chunk in current transaction,
4129                  * don't bother committing the transaction.
4130                  */
4131                 have_pinned_space = percpu_counter_compare(
4132                         &data_sinfo->total_bytes_pinned,
4133                         used + bytes - data_sinfo->total_bytes);
4134                 spin_unlock(&data_sinfo->lock);
4135
4136                 /* commit the current transaction and try again */
4137 commit_trans:
4138                 if (need_commit &&
4139                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
4140                         need_commit--;
4141
4142                         if (need_commit > 0) {
4143                                 btrfs_start_delalloc_roots(fs_info, 0, -1);
4144                                 btrfs_wait_ordered_roots(fs_info, -1);
4145                         }
4146
4147                         trans = btrfs_join_transaction(root);
4148                         if (IS_ERR(trans))
4149                                 return PTR_ERR(trans);
4150                         if (have_pinned_space >= 0 ||
4151                             test_bit(BTRFS_TRANS_HAVE_FREE_BGS,
4152                                      &trans->transaction->flags) ||
4153                             need_commit > 0) {
4154                                 ret = btrfs_commit_transaction(trans, root);
4155                                 if (ret)
4156                                         return ret;
4157                                 /*
4158                                  * The cleaner kthread might still be doing iput
4159                                  * operations. Wait for it to finish so that
4160                                  * more space is released.
4161                                  */
4162                                 mutex_lock(&root->fs_info->cleaner_delayed_iput_mutex);
4163                                 mutex_unlock(&root->fs_info->cleaner_delayed_iput_mutex);
4164                                 goto again;
4165                         } else {
4166                                 btrfs_end_transaction(trans, root);
4167                         }
4168                 }
4169
4170                 trace_btrfs_space_reservation(root->fs_info,
4171                                               "space_info:enospc",
4172                                               data_sinfo->flags, bytes, 1);
4173                 return -ENOSPC;
4174         }
4175         data_sinfo->bytes_may_use += bytes;
4176         trace_btrfs_space_reservation(root->fs_info, "space_info",
4177                                       data_sinfo->flags, bytes, 1);
4178         spin_unlock(&data_sinfo->lock);
4179
4180         return ret;
4181 }
4182
4183 /*
4184  * New check_data_free_space() with ability for precious data reservation
4185  * Will replace old btrfs_check_data_free_space(), but for patch split,
4186  * add a new function first and then replace it.
4187  */
4188 int btrfs_check_data_free_space(struct inode *inode, u64 start, u64 len)
4189 {
4190         struct btrfs_root *root = BTRFS_I(inode)->root;
4191         int ret;
4192
4193         /* align the range */
4194         len = round_up(start + len, root->sectorsize) -
4195               round_down(start, root->sectorsize);
4196         start = round_down(start, root->sectorsize);
4197
4198         ret = btrfs_alloc_data_chunk_ondemand(inode, len);
4199         if (ret < 0)
4200                 return ret;
4201
4202         /*
4203          * Use new btrfs_qgroup_reserve_data to reserve precious data space
4204          *
4205          * TODO: Find a good method to avoid reserve data space for NOCOW
4206          * range, but don't impact performance on quota disable case.
4207          */
4208         ret = btrfs_qgroup_reserve_data(inode, start, len);
4209         return ret;
4210 }
4211
4212 /*
4213  * Called if we need to clear a data reservation for this inode
4214  * Normally in a error case.
4215  *
4216  * This one will *NOT* use accurate qgroup reserved space API, just for case
4217  * which we can't sleep and is sure it won't affect qgroup reserved space.
4218  * Like clear_bit_hook().
4219  */
4220 void btrfs_free_reserved_data_space_noquota(struct inode *inode, u64 start,
4221                                             u64 len)
4222 {
4223         struct btrfs_root *root = BTRFS_I(inode)->root;
4224         struct btrfs_space_info *data_sinfo;
4225
4226         /* Make sure the range is aligned to sectorsize */
4227         len = round_up(start + len, root->sectorsize) -
4228               round_down(start, root->sectorsize);
4229         start = round_down(start, root->sectorsize);
4230
4231         data_sinfo = root->fs_info->data_sinfo;
4232         spin_lock(&data_sinfo->lock);
4233         if (WARN_ON(data_sinfo->bytes_may_use < len))
4234                 data_sinfo->bytes_may_use = 0;
4235         else
4236                 data_sinfo->bytes_may_use -= len;
4237         trace_btrfs_space_reservation(root->fs_info, "space_info",
4238                                       data_sinfo->flags, len, 0);
4239         spin_unlock(&data_sinfo->lock);
4240 }
4241
4242 /*
4243  * Called if we need to clear a data reservation for this inode
4244  * Normally in a error case.
4245  *
4246  * This one will handle the per-indoe data rsv map for accurate reserved
4247  * space framework.
4248  */
4249 void btrfs_free_reserved_data_space(struct inode *inode, u64 start, u64 len)
4250 {
4251         btrfs_free_reserved_data_space_noquota(inode, start, len);
4252         btrfs_qgroup_free_data(inode, start, len);
4253 }
4254
4255 static void force_metadata_allocation(struct btrfs_fs_info *info)
4256 {
4257         struct list_head *head = &info->space_info;
4258         struct btrfs_space_info *found;
4259
4260         rcu_read_lock();
4261         list_for_each_entry_rcu(found, head, list) {
4262                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
4263                         found->force_alloc = CHUNK_ALLOC_FORCE;
4264         }
4265         rcu_read_unlock();
4266 }
4267
4268 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
4269 {
4270         return (global->size << 1);
4271 }
4272
4273 static int should_alloc_chunk(struct btrfs_root *root,
4274                               struct btrfs_space_info *sinfo, int force)
4275 {
4276         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4277         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
4278         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
4279         u64 thresh;
4280
4281         if (force == CHUNK_ALLOC_FORCE)
4282                 return 1;
4283
4284         /*
4285          * We need to take into account the global rsv because for all intents
4286          * and purposes it's used space.  Don't worry about locking the
4287          * global_rsv, it doesn't change except when the transaction commits.
4288          */
4289         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
4290                 num_allocated += calc_global_rsv_need_space(global_rsv);
4291
4292         /*
4293          * in limited mode, we want to have some free space up to
4294          * about 1% of the FS size.
4295          */
4296         if (force == CHUNK_ALLOC_LIMITED) {
4297                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
4298                 thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
4299
4300                 if (num_bytes - num_allocated < thresh)
4301                         return 1;
4302         }
4303
4304         if (num_allocated + SZ_2M < div_factor(num_bytes, 8))
4305                 return 0;
4306         return 1;
4307 }
4308
4309 static u64 get_profile_num_devs(struct btrfs_root *root, u64 type)
4310 {
4311         u64 num_dev;
4312
4313         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
4314                     BTRFS_BLOCK_GROUP_RAID0 |
4315                     BTRFS_BLOCK_GROUP_RAID5 |
4316                     BTRFS_BLOCK_GROUP_RAID6))
4317                 num_dev = root->fs_info->fs_devices->rw_devices;
4318         else if (type & BTRFS_BLOCK_GROUP_RAID1)
4319                 num_dev = 2;
4320         else
4321                 num_dev = 1;    /* DUP or single */
4322
4323         return num_dev;
4324 }
4325
4326 /*
4327  * If @is_allocation is true, reserve space in the system space info necessary
4328  * for allocating a chunk, otherwise if it's false, reserve space necessary for
4329  * removing a chunk.
4330  */
4331 void check_system_chunk(struct btrfs_trans_handle *trans,
4332                         struct btrfs_root *root,
4333                         u64 type)
4334 {
4335         struct btrfs_space_info *info;
4336         u64 left;
4337         u64 thresh;
4338         int ret = 0;
4339         u64 num_devs;
4340
4341         /*
4342          * Needed because we can end up allocating a system chunk and for an
4343          * atomic and race free space reservation in the chunk block reserve.
4344          */
4345         ASSERT(mutex_is_locked(&root->fs_info->chunk_mutex));
4346
4347         info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4348         spin_lock(&info->lock);
4349         left = info->total_bytes - info->bytes_used - info->bytes_pinned -
4350                 info->bytes_reserved - info->bytes_readonly -
4351                 info->bytes_may_use;
4352         spin_unlock(&info->lock);
4353
4354         num_devs = get_profile_num_devs(root, type);
4355
4356         /* num_devs device items to update and 1 chunk item to add or remove */
4357         thresh = btrfs_calc_trunc_metadata_size(root, num_devs) +
4358                 btrfs_calc_trans_metadata_size(root, 1);
4359
4360         if (left < thresh && btrfs_test_opt(root, ENOSPC_DEBUG)) {
4361                 btrfs_info(root->fs_info, "left=%llu, need=%llu, flags=%llu",
4362                         left, thresh, type);
4363                 dump_space_info(info, 0, 0);
4364         }
4365
4366         if (left < thresh) {
4367                 u64 flags;
4368
4369                 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
4370                 /*
4371                  * Ignore failure to create system chunk. We might end up not
4372                  * needing it, as we might not need to COW all nodes/leafs from
4373                  * the paths we visit in the chunk tree (they were already COWed
4374                  * or created in the current transaction for example).
4375                  */
4376                 ret = btrfs_alloc_chunk(trans, root, flags);
4377         }
4378
4379         if (!ret) {
4380                 ret = btrfs_block_rsv_add(root->fs_info->chunk_root,
4381                                           &root->fs_info->chunk_block_rsv,
4382                                           thresh, BTRFS_RESERVE_NO_FLUSH);
4383                 if (!ret)
4384                         trans->chunk_bytes_reserved += thresh;
4385         }
4386 }
4387
4388 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
4389                           struct btrfs_root *extent_root, u64 flags, int force)
4390 {
4391         struct btrfs_space_info *space_info;
4392         struct btrfs_fs_info *fs_info = extent_root->fs_info;
4393         int wait_for_alloc = 0;
4394         int ret = 0;
4395
4396         /* Don't re-enter if we're already allocating a chunk */
4397         if (trans->allocating_chunk)
4398                 return -ENOSPC;
4399
4400         space_info = __find_space_info(extent_root->fs_info, flags);
4401         if (!space_info) {
4402                 ret = update_space_info(extent_root->fs_info, flags,
4403                                         0, 0, &space_info);
4404                 BUG_ON(ret); /* -ENOMEM */
4405         }
4406         BUG_ON(!space_info); /* Logic error */
4407
4408 again:
4409         spin_lock(&space_info->lock);
4410         if (force < space_info->force_alloc)
4411                 force = space_info->force_alloc;
4412         if (space_info->full) {
4413                 if (should_alloc_chunk(extent_root, space_info, force))
4414                         ret = -ENOSPC;
4415                 else
4416                         ret = 0;
4417                 spin_unlock(&space_info->lock);
4418                 return ret;
4419         }
4420
4421         if (!should_alloc_chunk(extent_root, space_info, force)) {
4422                 spin_unlock(&space_info->lock);
4423                 return 0;
4424         } else if (space_info->chunk_alloc) {
4425                 wait_for_alloc = 1;
4426         } else {
4427                 space_info->chunk_alloc = 1;
4428         }
4429
4430         spin_unlock(&space_info->lock);
4431
4432         mutex_lock(&fs_info->chunk_mutex);
4433
4434         /*
4435          * The chunk_mutex is held throughout the entirety of a chunk
4436          * allocation, so once we've acquired the chunk_mutex we know that the
4437          * other guy is done and we need to recheck and see if we should
4438          * allocate.
4439          */
4440         if (wait_for_alloc) {
4441                 mutex_unlock(&fs_info->chunk_mutex);
4442                 wait_for_alloc = 0;
4443                 goto again;
4444         }
4445
4446         trans->allocating_chunk = true;
4447
4448         /*
4449          * If we have mixed data/metadata chunks we want to make sure we keep
4450          * allocating mixed chunks instead of individual chunks.
4451          */
4452         if (btrfs_mixed_space_info(space_info))
4453                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
4454
4455         /*
4456          * if we're doing a data chunk, go ahead and make sure that
4457          * we keep a reasonable number of metadata chunks allocated in the
4458          * FS as well.
4459          */
4460         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
4461                 fs_info->data_chunk_allocations++;
4462                 if (!(fs_info->data_chunk_allocations %
4463                       fs_info->metadata_ratio))
4464                         force_metadata_allocation(fs_info);
4465         }
4466
4467         /*
4468          * Check if we have enough space in SYSTEM chunk because we may need
4469          * to update devices.
4470          */
4471         check_system_chunk(trans, extent_root, flags);
4472
4473         ret = btrfs_alloc_chunk(trans, extent_root, flags);
4474         trans->allocating_chunk = false;
4475
4476         spin_lock(&space_info->lock);
4477         if (ret < 0 && ret != -ENOSPC)
4478                 goto out;
4479         if (ret)
4480                 space_info->full = 1;
4481         else
4482                 ret = 1;
4483
4484         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4485 out:
4486         space_info->chunk_alloc = 0;
4487         spin_unlock(&space_info->lock);
4488         mutex_unlock(&fs_info->chunk_mutex);
4489         /*
4490          * When we allocate a new chunk we reserve space in the chunk block
4491          * reserve to make sure we can COW nodes/leafs in the chunk tree or
4492          * add new nodes/leafs to it if we end up needing to do it when
4493          * inserting the chunk item and updating device items as part of the
4494          * second phase of chunk allocation, performed by
4495          * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
4496          * large number of new block groups to create in our transaction
4497          * handle's new_bgs list to avoid exhausting the chunk block reserve
4498          * in extreme cases - like having a single transaction create many new
4499          * block groups when starting to write out the free space caches of all
4500          * the block groups that were made dirty during the lifetime of the
4501          * transaction.
4502          */
4503         if (trans->can_flush_pending_bgs &&
4504             trans->chunk_bytes_reserved >= (u64)SZ_2M) {
4505                 btrfs_create_pending_block_groups(trans, trans->root);
4506                 btrfs_trans_release_chunk_metadata(trans);
4507         }
4508         return ret;
4509 }
4510
4511 static int can_overcommit(struct btrfs_root *root,
4512                           struct btrfs_space_info *space_info, u64 bytes,
4513                           enum btrfs_reserve_flush_enum flush)
4514 {
4515         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4516         u64 profile = btrfs_get_alloc_profile(root, 0);
4517         u64 space_size;
4518         u64 avail;
4519         u64 used;
4520
4521         used = space_info->bytes_used + space_info->bytes_reserved +
4522                 space_info->bytes_pinned + space_info->bytes_readonly;
4523
4524         /*
4525          * We only want to allow over committing if we have lots of actual space
4526          * free, but if we don't have enough space to handle the global reserve
4527          * space then we could end up having a real enospc problem when trying
4528          * to allocate a chunk or some other such important allocation.
4529          */
4530         spin_lock(&global_rsv->lock);
4531         space_size = calc_global_rsv_need_space(global_rsv);
4532         spin_unlock(&global_rsv->lock);
4533         if (used + space_size >= space_info->total_bytes)
4534                 return 0;
4535
4536         used += space_info->bytes_may_use;
4537
4538         spin_lock(&root->fs_info->free_chunk_lock);
4539         avail = root->fs_info->free_chunk_space;
4540         spin_unlock(&root->fs_info->free_chunk_lock);
4541
4542         /*
4543          * If we have dup, raid1 or raid10 then only half of the free
4544          * space is actually useable.  For raid56, the space info used
4545          * doesn't include the parity drive, so we don't have to
4546          * change the math
4547          */
4548         if (profile & (BTRFS_BLOCK_GROUP_DUP |
4549                        BTRFS_BLOCK_GROUP_RAID1 |
4550                        BTRFS_BLOCK_GROUP_RAID10))
4551                 avail >>= 1;
4552
4553         /*
4554          * If we aren't flushing all things, let us overcommit up to
4555          * 1/2th of the space. If we can flush, don't let us overcommit
4556          * too much, let it overcommit up to 1/8 of the space.
4557          */
4558         if (flush == BTRFS_RESERVE_FLUSH_ALL)
4559                 avail >>= 3;
4560         else
4561                 avail >>= 1;
4562
4563         if (used + bytes < space_info->total_bytes + avail)
4564                 return 1;
4565         return 0;
4566 }
4567
4568 static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
4569                                          unsigned long nr_pages, int nr_items)
4570 {
4571         struct super_block *sb = root->fs_info->sb;
4572
4573         if (down_read_trylock(&sb->s_umount)) {
4574                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
4575                 up_read(&sb->s_umount);
4576         } else {
4577                 /*
4578                  * We needn't worry the filesystem going from r/w to r/o though
4579                  * we don't acquire ->s_umount mutex, because the filesystem
4580                  * should guarantee the delalloc inodes list be empty after
4581                  * the filesystem is readonly(all dirty pages are written to
4582                  * the disk).
4583                  */
4584                 btrfs_start_delalloc_roots(root->fs_info, 0, nr_items);
4585                 if (!current->journal_info)
4586                         btrfs_wait_ordered_roots(root->fs_info, nr_items);
4587         }
4588 }
4589
4590 static inline int calc_reclaim_items_nr(struct btrfs_root *root, u64 to_reclaim)
4591 {
4592         u64 bytes;
4593         int nr;
4594
4595         bytes = btrfs_calc_trans_metadata_size(root, 1);
4596         nr = (int)div64_u64(to_reclaim, bytes);
4597         if (!nr)
4598                 nr = 1;
4599         return nr;
4600 }
4601
4602 #define EXTENT_SIZE_PER_ITEM    SZ_256K
4603
4604 /*
4605  * shrink metadata reservation for delalloc
4606  */
4607 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
4608                             bool wait_ordered)
4609 {
4610         struct btrfs_block_rsv *block_rsv;
4611         struct btrfs_space_info *space_info;
4612         struct btrfs_trans_handle *trans;
4613         u64 delalloc_bytes;
4614         u64 max_reclaim;
4615         long time_left;
4616         unsigned long nr_pages;
4617         int loops;
4618         int items;
4619         enum btrfs_reserve_flush_enum flush;
4620
4621         /* Calc the number of the pages we need flush for space reservation */
4622         items = calc_reclaim_items_nr(root, to_reclaim);
4623         to_reclaim = items * EXTENT_SIZE_PER_ITEM;
4624
4625         trans = (struct btrfs_trans_handle *)current->journal_info;
4626         block_rsv = &root->fs_info->delalloc_block_rsv;
4627         space_info = block_rsv->space_info;
4628
4629         delalloc_bytes = percpu_counter_sum_positive(
4630                                                 &root->fs_info->delalloc_bytes);
4631         if (delalloc_bytes == 0) {
4632                 if (trans)
4633                         return;
4634                 if (wait_ordered)
4635                         btrfs_wait_ordered_roots(root->fs_info, items);
4636                 return;
4637         }
4638
4639         loops = 0;
4640         while (delalloc_bytes && loops < 3) {
4641                 max_reclaim = min(delalloc_bytes, to_reclaim);
4642                 nr_pages = max_reclaim >> PAGE_CACHE_SHIFT;
4643                 btrfs_writeback_inodes_sb_nr(root, nr_pages, items);
4644                 /*
4645                  * We need to wait for the async pages to actually start before
4646                  * we do anything.
4647                  */
4648                 max_reclaim = atomic_read(&root->fs_info->async_delalloc_pages);
4649                 if (!max_reclaim)
4650                         goto skip_async;
4651
4652                 if (max_reclaim <= nr_pages)
4653                         max_reclaim = 0;
4654                 else
4655                         max_reclaim -= nr_pages;
4656
4657                 wait_event(root->fs_info->async_submit_wait,
4658                            atomic_read(&root->fs_info->async_delalloc_pages) <=
4659                            (int)max_reclaim);
4660 skip_async:
4661                 if (!trans)
4662                         flush = BTRFS_RESERVE_FLUSH_ALL;
4663                 else
4664                         flush = BTRFS_RESERVE_NO_FLUSH;
4665                 spin_lock(&space_info->lock);
4666                 if (can_overcommit(root, space_info, orig, flush)) {
4667                         spin_unlock(&space_info->lock);
4668                         break;
4669                 }
4670                 spin_unlock(&space_info->lock);
4671
4672                 loops++;
4673                 if (wait_ordered && !trans) {
4674                         btrfs_wait_ordered_roots(root->fs_info, items);
4675                 } else {
4676                         time_left = schedule_timeout_killable(1);
4677                         if (time_left)
4678                                 break;
4679                 }
4680                 delalloc_bytes = percpu_counter_sum_positive(
4681                                                 &root->fs_info->delalloc_bytes);
4682         }
4683 }
4684
4685 /**
4686  * maybe_commit_transaction - possibly commit the transaction if its ok to
4687  * @root - the root we're allocating for
4688  * @bytes - the number of bytes we want to reserve
4689  * @force - force the commit
4690  *
4691  * This will check to make sure that committing the transaction will actually
4692  * get us somewhere and then commit the transaction if it does.  Otherwise it
4693  * will return -ENOSPC.
4694  */
4695 static int may_commit_transaction(struct btrfs_root *root,
4696                                   struct btrfs_space_info *space_info,
4697                                   u64 bytes, int force)
4698 {
4699         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
4700         struct btrfs_trans_handle *trans;
4701
4702         trans = (struct btrfs_trans_handle *)current->journal_info;
4703         if (trans)
4704                 return -EAGAIN;
4705
4706         if (force)
4707                 goto commit;
4708
4709         /* See if there is enough pinned space to make this reservation */
4710         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4711                                    bytes) >= 0)
4712                 goto commit;
4713
4714         /*
4715          * See if there is some space in the delayed insertion reservation for
4716          * this reservation.
4717          */
4718         if (space_info != delayed_rsv->space_info)
4719                 return -ENOSPC;
4720
4721         spin_lock(&delayed_rsv->lock);
4722         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4723                                    bytes - delayed_rsv->size) >= 0) {
4724                 spin_unlock(&delayed_rsv->lock);
4725                 return -ENOSPC;
4726         }
4727         spin_unlock(&delayed_rsv->lock);
4728
4729 commit:
4730         trans = btrfs_join_transaction(root);
4731         if (IS_ERR(trans))
4732                 return -ENOSPC;
4733
4734         return btrfs_commit_transaction(trans, root);
4735 }
4736
4737 enum flush_state {
4738         FLUSH_DELAYED_ITEMS_NR  =       1,
4739         FLUSH_DELAYED_ITEMS     =       2,
4740         FLUSH_DELALLOC          =       3,
4741         FLUSH_DELALLOC_WAIT     =       4,
4742         ALLOC_CHUNK             =       5,
4743         COMMIT_TRANS            =       6,
4744 };
4745
4746 static int flush_space(struct btrfs_root *root,
4747                        struct btrfs_space_info *space_info, u64 num_bytes,
4748                        u64 orig_bytes, int state)
4749 {
4750         struct btrfs_trans_handle *trans;
4751         int nr;
4752         int ret = 0;
4753
4754         switch (state) {
4755         case FLUSH_DELAYED_ITEMS_NR:
4756         case FLUSH_DELAYED_ITEMS:
4757                 if (state == FLUSH_DELAYED_ITEMS_NR)
4758                         nr = calc_reclaim_items_nr(root, num_bytes) * 2;
4759                 else
4760                         nr = -1;
4761
4762                 trans = btrfs_join_transaction(root);
4763                 if (IS_ERR(trans)) {
4764                         ret = PTR_ERR(trans);
4765                         break;
4766                 }
4767                 ret = btrfs_run_delayed_items_nr(trans, root, nr);
4768                 btrfs_end_transaction(trans, root);
4769                 break;
4770         case FLUSH_DELALLOC:
4771         case FLUSH_DELALLOC_WAIT:
4772                 shrink_delalloc(root, num_bytes * 2, orig_bytes,
4773                                 state == FLUSH_DELALLOC_WAIT);
4774                 break;
4775         case ALLOC_CHUNK:
4776                 trans = btrfs_join_transaction(root);
4777                 if (IS_ERR(trans)) {
4778                         ret = PTR_ERR(trans);
4779                         break;
4780                 }
4781                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4782                                      btrfs_get_alloc_profile(root, 0),
4783                                      CHUNK_ALLOC_NO_FORCE);
4784                 btrfs_end_transaction(trans, root);
4785                 if (ret == -ENOSPC)
4786                         ret = 0;
4787                 break;
4788         case COMMIT_TRANS:
4789                 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
4790                 break;
4791         default:
4792                 ret = -ENOSPC;
4793                 break;
4794         }
4795
4796         return ret;
4797 }
4798
4799 static inline u64
4800 btrfs_calc_reclaim_metadata_size(struct btrfs_root *root,
4801                                  struct btrfs_space_info *space_info)
4802 {
4803         u64 used;
4804         u64 expected;
4805         u64 to_reclaim;
4806
4807         to_reclaim = min_t(u64, num_online_cpus() * SZ_1M, SZ_16M);
4808         spin_lock(&space_info->lock);
4809         if (can_overcommit(root, space_info, to_reclaim,
4810                            BTRFS_RESERVE_FLUSH_ALL)) {
4811                 to_reclaim = 0;
4812                 goto out;
4813         }
4814
4815         used = space_info->bytes_used + space_info->bytes_reserved +
4816                space_info->bytes_pinned + space_info->bytes_readonly +
4817                space_info->bytes_may_use;
4818         if (can_overcommit(root, space_info, SZ_1M, BTRFS_RESERVE_FLUSH_ALL))
4819                 expected = div_factor_fine(space_info->total_bytes, 95);
4820         else
4821                 expected = div_factor_fine(space_info->total_bytes, 90);
4822
4823         if (used > expected)
4824                 to_reclaim = used - expected;
4825         else
4826                 to_reclaim = 0;
4827         to_reclaim = min(to_reclaim, space_info->bytes_may_use +
4828                                      space_info->bytes_reserved);
4829 out:
4830         spin_unlock(&space_info->lock);
4831
4832         return to_reclaim;
4833 }
4834
4835 static inline int need_do_async_reclaim(struct btrfs_space_info *space_info,
4836                                         struct btrfs_fs_info *fs_info, u64 used)
4837 {
4838         u64 thresh = div_factor_fine(space_info->total_bytes, 98);
4839
4840         /* If we're just plain full then async reclaim just slows us down. */
4841         if (space_info->bytes_used >= thresh)
4842                 return 0;
4843
4844         return (used >= thresh && !btrfs_fs_closing(fs_info) &&
4845                 !test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state));
4846 }
4847
4848 static int btrfs_need_do_async_reclaim(struct btrfs_space_info *space_info,
4849                                        struct btrfs_fs_info *fs_info,
4850                                        int flush_state)
4851 {
4852         u64 used;
4853
4854         spin_lock(&space_info->lock);
4855         /*
4856          * We run out of space and have not got any free space via flush_space,
4857          * so don't bother doing async reclaim.
4858          */
4859         if (flush_state > COMMIT_TRANS && space_info->full) {
4860                 spin_unlock(&space_info->lock);
4861                 return 0;
4862         }
4863
4864         used = space_info->bytes_used + space_info->bytes_reserved +
4865                space_info->bytes_pinned + space_info->bytes_readonly +
4866                space_info->bytes_may_use;
4867         if (need_do_async_reclaim(space_info, fs_info, used)) {
4868                 spin_unlock(&space_info->lock);
4869                 return 1;
4870         }
4871         spin_unlock(&space_info->lock);
4872
4873         return 0;
4874 }
4875
4876 static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
4877 {
4878         struct btrfs_fs_info *fs_info;
4879         struct btrfs_space_info *space_info;
4880         u64 to_reclaim;
4881         int flush_state;
4882
4883         fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
4884         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4885
4886         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
4887                                                       space_info);
4888         if (!to_reclaim)
4889                 return;
4890
4891         flush_state = FLUSH_DELAYED_ITEMS_NR;
4892         do {
4893                 flush_space(fs_info->fs_root, space_info, to_reclaim,
4894                             to_reclaim, flush_state);
4895                 flush_state++;
4896                 if (!btrfs_need_do_async_reclaim(space_info, fs_info,
4897                                                  flush_state))
4898                         return;
4899         } while (flush_state < COMMIT_TRANS);
4900 }
4901
4902 void btrfs_init_async_reclaim_work(struct work_struct *work)
4903 {
4904         INIT_WORK(work, btrfs_async_reclaim_metadata_space);
4905 }
4906
4907 /**
4908  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
4909  * @root - the root we're allocating for
4910  * @block_rsv - the block_rsv we're allocating for
4911  * @orig_bytes - the number of bytes we want
4912  * @flush - whether or not we can flush to make our reservation
4913  *
4914  * This will reserve orgi_bytes number of bytes from the space info associated
4915  * with the block_rsv.  If there is not enough space it will make an attempt to
4916  * flush out space to make room.  It will do this by flushing delalloc if
4917  * possible or committing the transaction.  If flush is 0 then no attempts to
4918  * regain reservations will be made and this will fail if there is not enough
4919  * space already.
4920  */
4921 static int reserve_metadata_bytes(struct btrfs_root *root,
4922                                   struct btrfs_block_rsv *block_rsv,
4923                                   u64 orig_bytes,
4924                                   enum btrfs_reserve_flush_enum flush)
4925 {
4926         struct btrfs_space_info *space_info = block_rsv->space_info;
4927         u64 used;
4928         u64 num_bytes = orig_bytes;
4929         int flush_state = FLUSH_DELAYED_ITEMS_NR;
4930         int ret = 0;
4931         bool flushing = false;
4932
4933 again:
4934         ret = 0;
4935         spin_lock(&space_info->lock);
4936         /*
4937          * We only want to wait if somebody other than us is flushing and we
4938          * are actually allowed to flush all things.
4939          */
4940         while (flush == BTRFS_RESERVE_FLUSH_ALL && !flushing &&
4941                space_info->flush) {
4942                 spin_unlock(&space_info->lock);
4943                 /*
4944                  * If we have a trans handle we can't wait because the flusher
4945                  * may have to commit the transaction, which would mean we would
4946                  * deadlock since we are waiting for the flusher to finish, but
4947                  * hold the current transaction open.
4948                  */
4949                 if (current->journal_info)
4950                         return -EAGAIN;
4951                 ret = wait_event_killable(space_info->wait, !space_info->flush);
4952                 /* Must have been killed, return */
4953                 if (ret)
4954                         return -EINTR;
4955
4956                 spin_lock(&space_info->lock);
4957         }
4958
4959         ret = -ENOSPC;
4960         used = space_info->bytes_used + space_info->bytes_reserved +
4961                 space_info->bytes_pinned + space_info->bytes_readonly +
4962                 space_info->bytes_may_use;
4963
4964         /*
4965          * The idea here is that we've not already over-reserved the block group
4966          * then we can go ahead and save our reservation first and then start
4967          * flushing if we need to.  Otherwise if we've already overcommitted
4968          * lets start flushing stuff first and then come back and try to make
4969          * our reservation.
4970          */
4971         if (used <= space_info->total_bytes) {
4972                 if (used + orig_bytes <= space_info->total_bytes) {
4973                         space_info->bytes_may_use += orig_bytes;
4974                         trace_btrfs_space_reservation(root->fs_info,
4975                                 "space_info", space_info->flags, orig_bytes, 1);
4976                         ret = 0;
4977                 } else {
4978                         /*
4979                          * Ok set num_bytes to orig_bytes since we aren't
4980                          * overocmmitted, this way we only try and reclaim what
4981                          * we need.
4982                          */
4983                         num_bytes = orig_bytes;
4984                 }
4985         } else {
4986                 /*
4987                  * Ok we're over committed, set num_bytes to the overcommitted
4988                  * amount plus the amount of bytes that we need for this
4989                  * reservation.
4990                  */
4991                 num_bytes = used - space_info->total_bytes +
4992                         (orig_bytes * 2);
4993         }
4994
4995         if (ret && can_overcommit(root, space_info, orig_bytes, flush)) {
4996                 space_info->bytes_may_use += orig_bytes;
4997                 trace_btrfs_space_reservation(root->fs_info, "space_info",
4998                                               space_info->flags, orig_bytes,
4999                                               1);
5000                 ret = 0;
5001         }
5002
5003         /*
5004          * Couldn't make our reservation, save our place so while we're trying
5005          * to reclaim space we can actually use it instead of somebody else
5006          * stealing it from us.
5007          *
5008          * We make the other tasks wait for the flush only when we can flush
5009          * all things.
5010          */
5011         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
5012                 flushing = true;
5013                 space_info->flush = 1;
5014         } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
5015                 used += orig_bytes;
5016                 /*
5017                  * We will do the space reservation dance during log replay,
5018                  * which means we won't have fs_info->fs_root set, so don't do
5019                  * the async reclaim as we will panic.
5020                  */
5021                 if (!root->fs_info->log_root_recovering &&
5022                     need_do_async_reclaim(space_info, root->fs_info, used) &&
5023                     !work_busy(&root->fs_info->async_reclaim_work))
5024                         queue_work(system_unbound_wq,
5025                                    &root->fs_info->async_reclaim_work);
5026         }
5027         spin_unlock(&space_info->lock);
5028
5029         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
5030                 goto out;
5031
5032         ret = flush_space(root, space_info, num_bytes, orig_bytes,
5033                           flush_state);
5034         flush_state++;
5035
5036         /*
5037          * If we are FLUSH_LIMIT, we can not flush delalloc, or the deadlock
5038          * would happen. So skip delalloc flush.
5039          */
5040         if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
5041             (flush_state == FLUSH_DELALLOC ||
5042              flush_state == FLUSH_DELALLOC_WAIT))
5043                 flush_state = ALLOC_CHUNK;
5044
5045         if (!ret)
5046                 goto again;
5047         else if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
5048                  flush_state < COMMIT_TRANS)
5049                 goto again;
5050         else if (flush == BTRFS_RESERVE_FLUSH_ALL &&
5051                  flush_state <= COMMIT_TRANS)
5052                 goto again;
5053
5054 out:
5055         if (ret == -ENOSPC &&
5056             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
5057                 struct btrfs_block_rsv *global_rsv =
5058                         &root->fs_info->global_block_rsv;
5059
5060                 if (block_rsv != global_rsv &&
5061                     !block_rsv_use_bytes(global_rsv, orig_bytes))
5062                         ret = 0;
5063         }
5064         if (ret == -ENOSPC)
5065                 trace_btrfs_space_reservation(root->fs_info,
5066                                               "space_info:enospc",
5067                                               space_info->flags, orig_bytes, 1);
5068         if (flushing) {
5069                 spin_lock(&space_info->lock);
5070                 space_info->flush = 0;
5071                 wake_up_all(&space_info->wait);
5072                 spin_unlock(&space_info->lock);
5073         }
5074         return ret;
5075 }
5076
5077 static struct btrfs_block_rsv *get_block_rsv(
5078                                         const struct btrfs_trans_handle *trans,
5079                                         const struct btrfs_root *root)
5080 {
5081         struct btrfs_block_rsv *block_rsv = NULL;
5082
5083         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
5084             (root == root->fs_info->csum_root && trans->adding_csums) ||
5085              (root == root->fs_info->uuid_root))
5086                 block_rsv = trans->block_rsv;
5087
5088         if (!block_rsv)
5089                 block_rsv = root->block_rsv;
5090
5091         if (!block_rsv)
5092                 block_rsv = &root->fs_info->empty_block_rsv;
5093
5094         return block_rsv;
5095 }
5096
5097 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
5098                                u64 num_bytes)
5099 {
5100         int ret = -ENOSPC;
5101         spin_lock(&block_rsv->lock);
5102         if (block_rsv->reserved >= num_bytes) {
5103                 block_rsv->reserved -= num_bytes;
5104                 if (block_rsv->reserved < block_rsv->size)
5105                         block_rsv->full = 0;
5106                 ret = 0;
5107         }
5108         spin_unlock(&block_rsv->lock);
5109         return ret;
5110 }
5111
5112 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
5113                                 u64 num_bytes, int update_size)
5114 {
5115         spin_lock(&block_rsv->lock);
5116         block_rsv->reserved += num_bytes;
5117         if (update_size)
5118                 block_rsv->size += num_bytes;
5119         else if (block_rsv->reserved >= block_rsv->size)
5120                 block_rsv->full = 1;
5121         spin_unlock(&block_rsv->lock);
5122 }
5123
5124 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
5125                              struct btrfs_block_rsv *dest, u64 num_bytes,
5126                              int min_factor)
5127 {
5128         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5129         u64 min_bytes;
5130
5131         if (global_rsv->space_info != dest->space_info)
5132                 return -ENOSPC;
5133
5134         spin_lock(&global_rsv->lock);
5135         min_bytes = div_factor(global_rsv->size, min_factor);
5136         if (global_rsv->reserved < min_bytes + num_bytes) {
5137                 spin_unlock(&global_rsv->lock);
5138                 return -ENOSPC;
5139         }
5140         global_rsv->reserved -= num_bytes;
5141         if (global_rsv->reserved < global_rsv->size)
5142                 global_rsv->full = 0;
5143         spin_unlock(&global_rsv->lock);
5144
5145         block_rsv_add_bytes(dest, num_bytes, 1);
5146         return 0;
5147 }
5148
5149 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
5150                                     struct btrfs_block_rsv *block_rsv,
5151                                     struct btrfs_block_rsv *dest, u64 num_bytes)
5152 {
5153         struct btrfs_space_info *space_info = block_rsv->space_info;
5154
5155         spin_lock(&block_rsv->lock);
5156         if (num_bytes == (u64)-1)
5157                 num_bytes = block_rsv->size;
5158         block_rsv->size -= num_bytes;
5159         if (block_rsv->reserved >= block_rsv->size) {
5160                 num_bytes = block_rsv->reserved - block_rsv->size;
5161                 block_rsv->reserved = block_rsv->size;
5162                 block_rsv->full = 1;
5163         } else {
5164                 num_bytes = 0;
5165         }
5166         spin_unlock(&block_rsv->lock);
5167
5168         if (num_bytes > 0) {
5169                 if (dest) {
5170                         spin_lock(&dest->lock);
5171                         if (!dest->full) {
5172                                 u64 bytes_to_add;
5173
5174                                 bytes_to_add = dest->size - dest->reserved;
5175                                 bytes_to_add = min(num_bytes, bytes_to_add);
5176                                 dest->reserved += bytes_to_add;
5177                                 if (dest->reserved >= dest->size)
5178                                         dest->full = 1;
5179                                 num_bytes -= bytes_to_add;
5180                         }
5181                         spin_unlock(&dest->lock);
5182                 }
5183                 if (num_bytes) {
5184                         spin_lock(&space_info->lock);
5185                         space_info->bytes_may_use -= num_bytes;
5186                         trace_btrfs_space_reservation(fs_info, "space_info",
5187                                         space_info->flags, num_bytes, 0);
5188                         spin_unlock(&space_info->lock);
5189                 }
5190         }
5191 }
5192
5193 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
5194                                    struct btrfs_block_rsv *dst, u64 num_bytes)
5195 {
5196         int ret;
5197
5198         ret = block_rsv_use_bytes(src, num_bytes);
5199         if (ret)
5200                 return ret;
5201
5202         block_rsv_add_bytes(dst, num_bytes, 1);
5203         return 0;
5204 }
5205
5206 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
5207 {
5208         memset(rsv, 0, sizeof(*rsv));
5209         spin_lock_init(&rsv->lock);
5210         rsv->type = type;
5211 }
5212
5213 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
5214                                               unsigned short type)
5215 {
5216         struct btrfs_block_rsv *block_rsv;
5217         struct btrfs_fs_info *fs_info = root->fs_info;
5218
5219         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
5220         if (!block_rsv)
5221                 return NULL;
5222
5223         btrfs_init_block_rsv(block_rsv, type);
5224         block_rsv->space_info = __find_space_info(fs_info,
5225                                                   BTRFS_BLOCK_GROUP_METADATA);
5226         return block_rsv;
5227 }
5228
5229 void btrfs_free_block_rsv(struct btrfs_root *root,
5230                           struct btrfs_block_rsv *rsv)
5231 {
5232         if (!rsv)
5233                 return;
5234         btrfs_block_rsv_release(root, rsv, (u64)-1);
5235         kfree(rsv);
5236 }
5237
5238 void __btrfs_free_block_rsv(struct btrfs_block_rsv *rsv)
5239 {
5240         kfree(rsv);
5241 }
5242
5243 int btrfs_block_rsv_add(struct btrfs_root *root,
5244                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
5245                         enum btrfs_reserve_flush_enum flush)
5246 {
5247         int ret;
5248
5249         if (num_bytes == 0)
5250                 return 0;
5251
5252         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5253         if (!ret) {
5254                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
5255                 return 0;
5256         }
5257
5258         return ret;
5259 }
5260
5261 int btrfs_block_rsv_check(struct btrfs_root *root,
5262                           struct btrfs_block_rsv *block_rsv, int min_factor)
5263 {
5264         u64 num_bytes = 0;
5265         int ret = -ENOSPC;
5266
5267         if (!block_rsv)
5268                 return 0;
5269
5270         spin_lock(&block_rsv->lock);
5271         num_bytes = div_factor(block_rsv->size, min_factor);
5272         if (block_rsv->reserved >= num_bytes)
5273                 ret = 0;
5274         spin_unlock(&block_rsv->lock);
5275
5276         return ret;
5277 }
5278
5279 int btrfs_block_rsv_refill(struct btrfs_root *root,
5280                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
5281                            enum btrfs_reserve_flush_enum flush)
5282 {
5283         u64 num_bytes = 0;
5284         int ret = -ENOSPC;
5285
5286         if (!block_rsv)
5287                 return 0;
5288
5289         spin_lock(&block_rsv->lock);
5290         num_bytes = min_reserved;
5291         if (block_rsv->reserved >= num_bytes)
5292                 ret = 0;
5293         else
5294                 num_bytes -= block_rsv->reserved;
5295         spin_unlock(&block_rsv->lock);
5296
5297         if (!ret)
5298                 return 0;
5299
5300         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5301         if (!ret) {
5302                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
5303                 return 0;
5304         }
5305
5306         return ret;
5307 }
5308
5309 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
5310                             struct btrfs_block_rsv *dst_rsv,
5311                             u64 num_bytes)
5312 {
5313         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
5314 }
5315
5316 void btrfs_block_rsv_release(struct btrfs_root *root,
5317                              struct btrfs_block_rsv *block_rsv,
5318                              u64 num_bytes)
5319 {
5320         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5321         if (global_rsv == block_rsv ||
5322             block_rsv->space_info != global_rsv->space_info)
5323                 global_rsv = NULL;
5324         block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
5325                                 num_bytes);
5326 }
5327
5328 /*
5329  * helper to calculate size of global block reservation.
5330  * the desired value is sum of space used by extent tree,
5331  * checksum tree and root tree
5332  */
5333 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
5334 {
5335         struct btrfs_space_info *sinfo;
5336         u64 num_bytes;
5337         u64 meta_used;
5338         u64 data_used;
5339         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
5340
5341         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
5342         spin_lock(&sinfo->lock);
5343         data_used = sinfo->bytes_used;
5344         spin_unlock(&sinfo->lock);
5345
5346         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5347         spin_lock(&sinfo->lock);
5348         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
5349                 data_used = 0;
5350         meta_used = sinfo->bytes_used;
5351         spin_unlock(&sinfo->lock);
5352
5353         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
5354                     csum_size * 2;
5355         num_bytes += div_u64(data_used + meta_used, 50);
5356
5357         if (num_bytes * 3 > meta_used)
5358                 num_bytes = div_u64(meta_used, 3);
5359
5360         return ALIGN(num_bytes, fs_info->extent_root->nodesize << 10);
5361 }
5362
5363 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
5364 {
5365         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
5366         struct btrfs_space_info *sinfo = block_rsv->space_info;
5367         u64 num_bytes;
5368
5369         num_bytes = calc_global_metadata_size(fs_info);
5370
5371         spin_lock(&sinfo->lock);
5372         spin_lock(&block_rsv->lock);
5373
5374         block_rsv->size = min_t(u64, num_bytes, SZ_512M);
5375
5376         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
5377                     sinfo->bytes_reserved + sinfo->bytes_readonly +
5378                     sinfo->bytes_may_use;
5379
5380         if (sinfo->total_bytes > num_bytes) {
5381                 num_bytes = sinfo->total_bytes - num_bytes;
5382                 block_rsv->reserved += num_bytes;
5383                 sinfo->bytes_may_use += num_bytes;
5384                 trace_btrfs_space_reservation(fs_info, "space_info",
5385                                       sinfo->flags, num_bytes, 1);
5386         }
5387
5388         if (block_rsv->reserved >= block_rsv->size) {
5389                 num_bytes = block_rsv->reserved - block_rsv->size;
5390                 sinfo->bytes_may_use -= num_bytes;
5391                 trace_btrfs_space_reservation(fs_info, "space_info",
5392                                       sinfo->flags, num_bytes, 0);
5393                 block_rsv->reserved = block_rsv->size;
5394                 block_rsv->full = 1;
5395         }
5396
5397         spin_unlock(&block_rsv->lock);
5398         spin_unlock(&sinfo->lock);
5399 }
5400
5401 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
5402 {
5403         struct btrfs_space_info *space_info;
5404
5405         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
5406         fs_info->chunk_block_rsv.space_info = space_info;
5407
5408         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5409         fs_info->global_block_rsv.space_info = space_info;
5410         fs_info->delalloc_block_rsv.space_info = space_info;
5411         fs_info->trans_block_rsv.space_info = space_info;
5412         fs_info->empty_block_rsv.space_info = space_info;
5413         fs_info->delayed_block_rsv.space_info = space_info;
5414
5415         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
5416         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
5417         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
5418         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
5419         if (fs_info->quota_root)
5420                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
5421         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
5422
5423         update_global_block_rsv(fs_info);
5424 }
5425
5426 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
5427 {
5428         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
5429                                 (u64)-1);
5430         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
5431         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
5432         WARN_ON(fs_info->trans_block_rsv.size > 0);
5433         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
5434         WARN_ON(fs_info->chunk_block_rsv.size > 0);
5435         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
5436         WARN_ON(fs_info->delayed_block_rsv.size > 0);
5437         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
5438 }
5439
5440 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
5441                                   struct btrfs_root *root)
5442 {
5443         if (!trans->block_rsv)
5444                 return;
5445
5446         if (!trans->bytes_reserved)
5447                 return;
5448
5449         trace_btrfs_space_reservation(root->fs_info, "transaction",
5450                                       trans->transid, trans->bytes_reserved, 0);
5451         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
5452         trans->bytes_reserved = 0;
5453 }
5454
5455 /*
5456  * To be called after all the new block groups attached to the transaction
5457  * handle have been created (btrfs_create_pending_block_groups()).
5458  */
5459 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
5460 {
5461         struct btrfs_fs_info *fs_info = trans->root->fs_info;
5462
5463         if (!trans->chunk_bytes_reserved)
5464                 return;
5465
5466         WARN_ON_ONCE(!list_empty(&trans->new_bgs));
5467
5468         block_rsv_release_bytes(fs_info, &fs_info->chunk_block_rsv, NULL,
5469                                 trans->chunk_bytes_reserved);
5470         trans->chunk_bytes_reserved = 0;
5471 }
5472
5473 /* Can only return 0 or -ENOSPC */
5474 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
5475                                   struct inode *inode)
5476 {
5477         struct btrfs_root *root = BTRFS_I(inode)->root;
5478         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
5479         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
5480
5481         /*
5482          * We need to hold space in order to delete our orphan item once we've
5483          * added it, so this takes the reservation so we can release it later
5484          * when we are truly done with the orphan item.
5485          */
5486         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5487         trace_btrfs_space_reservation(root->fs_info, "orphan",
5488                                       btrfs_ino(inode), num_bytes, 1);
5489         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
5490 }
5491
5492 void btrfs_orphan_release_metadata(struct inode *inode)
5493 {
5494         struct btrfs_root *root = BTRFS_I(inode)->root;
5495         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5496         trace_btrfs_space_reservation(root->fs_info, "orphan",
5497                                       btrfs_ino(inode), num_bytes, 0);
5498         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
5499 }
5500
5501 /*
5502  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
5503  * root: the root of the parent directory
5504  * rsv: block reservation
5505  * items: the number of items that we need do reservation
5506  * qgroup_reserved: used to return the reserved size in qgroup
5507  *
5508  * This function is used to reserve the space for snapshot/subvolume
5509  * creation and deletion. Those operations are different with the
5510  * common file/directory operations, they change two fs/file trees
5511  * and root tree, the number of items that the qgroup reserves is
5512  * different with the free space reservation. So we can not use
5513  * the space reseravtion mechanism in start_transaction().
5514  */
5515 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
5516                                      struct btrfs_block_rsv *rsv,
5517                                      int items,
5518                                      u64 *qgroup_reserved,
5519                                      bool use_global_rsv)
5520 {
5521         u64 num_bytes;
5522         int ret;
5523         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5524
5525         if (root->fs_info->quota_enabled) {
5526                 /* One for parent inode, two for dir entries */
5527                 num_bytes = 3 * root->nodesize;
5528                 ret = btrfs_qgroup_reserve_meta(root, num_bytes);
5529                 if (ret)
5530                         return ret;
5531         } else {
5532                 num_bytes = 0;
5533         }
5534
5535         *qgroup_reserved = num_bytes;
5536
5537         num_bytes = btrfs_calc_trans_metadata_size(root, items);
5538         rsv->space_info = __find_space_info(root->fs_info,
5539                                             BTRFS_BLOCK_GROUP_METADATA);
5540         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
5541                                   BTRFS_RESERVE_FLUSH_ALL);
5542
5543         if (ret == -ENOSPC && use_global_rsv)
5544                 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes);
5545
5546         if (ret && *qgroup_reserved)
5547                 btrfs_qgroup_free_meta(root, *qgroup_reserved);
5548
5549         return ret;
5550 }
5551
5552 void btrfs_subvolume_release_metadata(struct btrfs_root *root,
5553                                       struct btrfs_block_rsv *rsv,
5554                                       u64 qgroup_reserved)
5555 {
5556         btrfs_block_rsv_release(root, rsv, (u64)-1);
5557 }
5558
5559 /**
5560  * drop_outstanding_extent - drop an outstanding extent
5561  * @inode: the inode we're dropping the extent for
5562  * @num_bytes: the number of bytes we're relaseing.
5563  *
5564  * This is called when we are freeing up an outstanding extent, either called
5565  * after an error or after an extent is written.  This will return the number of
5566  * reserved extents that need to be freed.  This must be called with
5567  * BTRFS_I(inode)->lock held.
5568  */
5569 static unsigned drop_outstanding_extent(struct inode *inode, u64 num_bytes)
5570 {
5571         unsigned drop_inode_space = 0;
5572         unsigned dropped_extents = 0;
5573         unsigned num_extents = 0;
5574
5575         num_extents = (unsigned)div64_u64(num_bytes +
5576                                           BTRFS_MAX_EXTENT_SIZE - 1,
5577                                           BTRFS_MAX_EXTENT_SIZE);
5578         ASSERT(num_extents);
5579         ASSERT(BTRFS_I(inode)->outstanding_extents >= num_extents);
5580         BTRFS_I(inode)->outstanding_extents -= num_extents;
5581
5582         if (BTRFS_I(inode)->outstanding_extents == 0 &&
5583             test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5584                                &BTRFS_I(inode)->runtime_flags))
5585                 drop_inode_space = 1;
5586
5587         /*
5588          * If we have more or the same amount of outsanding extents than we have
5589          * reserved then we need to leave the reserved extents count alone.
5590          */
5591         if (BTRFS_I(inode)->outstanding_extents >=
5592             BTRFS_I(inode)->reserved_extents)
5593                 return drop_inode_space;
5594
5595         dropped_extents = BTRFS_I(inode)->reserved_extents -
5596                 BTRFS_I(inode)->outstanding_extents;
5597         BTRFS_I(inode)->reserved_extents -= dropped_extents;
5598         return dropped_extents + drop_inode_space;
5599 }
5600
5601 /**
5602  * calc_csum_metadata_size - return the amount of metada space that must be
5603  *      reserved/free'd for the given bytes.
5604  * @inode: the inode we're manipulating
5605  * @num_bytes: the number of bytes in question
5606  * @reserve: 1 if we are reserving space, 0 if we are freeing space
5607  *
5608  * This adjusts the number of csum_bytes in the inode and then returns the
5609  * correct amount of metadata that must either be reserved or freed.  We
5610  * calculate how many checksums we can fit into one leaf and then divide the
5611  * number of bytes that will need to be checksumed by this value to figure out
5612  * how many checksums will be required.  If we are adding bytes then the number
5613  * may go up and we will return the number of additional bytes that must be
5614  * reserved.  If it is going down we will return the number of bytes that must
5615  * be freed.
5616  *
5617  * This must be called with BTRFS_I(inode)->lock held.
5618  */
5619 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
5620                                    int reserve)
5621 {
5622         struct btrfs_root *root = BTRFS_I(inode)->root;
5623         u64 old_csums, num_csums;
5624
5625         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
5626             BTRFS_I(inode)->csum_bytes == 0)
5627                 return 0;
5628
5629         old_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5630         if (reserve)
5631                 BTRFS_I(inode)->csum_bytes += num_bytes;
5632         else
5633                 BTRFS_I(inode)->csum_bytes -= num_bytes;
5634         num_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5635
5636         /* No change, no need to reserve more */
5637         if (old_csums == num_csums)
5638                 return 0;
5639
5640         if (reserve)
5641                 return btrfs_calc_trans_metadata_size(root,
5642                                                       num_csums - old_csums);
5643
5644         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
5645 }
5646
5647 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
5648 {
5649         struct btrfs_root *root = BTRFS_I(inode)->root;
5650         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
5651         u64 to_reserve = 0;
5652         u64 csum_bytes;
5653         unsigned nr_extents = 0;
5654         int extra_reserve = 0;
5655         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
5656         int ret = 0;
5657         bool delalloc_lock = true;
5658         u64 to_free = 0;
5659         unsigned dropped;
5660
5661         /* If we are a free space inode we need to not flush since we will be in
5662          * the middle of a transaction commit.  We also don't need the delalloc
5663          * mutex since we won't race with anybody.  We need this mostly to make
5664          * lockdep shut its filthy mouth.
5665          */
5666         if (btrfs_is_free_space_inode(inode)) {
5667                 flush = BTRFS_RESERVE_NO_FLUSH;
5668                 delalloc_lock = false;
5669         }
5670
5671         if (flush != BTRFS_RESERVE_NO_FLUSH &&
5672             btrfs_transaction_in_commit(root->fs_info))
5673                 schedule_timeout(1);
5674
5675         if (delalloc_lock)
5676                 mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
5677
5678         num_bytes = ALIGN(num_bytes, root->sectorsize);
5679
5680         spin_lock(&BTRFS_I(inode)->lock);
5681         nr_extents = (unsigned)div64_u64(num_bytes +
5682                                          BTRFS_MAX_EXTENT_SIZE - 1,
5683                                          BTRFS_MAX_EXTENT_SIZE);
5684         BTRFS_I(inode)->outstanding_extents += nr_extents;
5685         nr_extents = 0;
5686
5687         if (BTRFS_I(inode)->outstanding_extents >
5688             BTRFS_I(inode)->reserved_extents)
5689                 nr_extents = BTRFS_I(inode)->outstanding_extents -
5690                         BTRFS_I(inode)->reserved_extents;
5691
5692         /*
5693          * Add an item to reserve for updating the inode when we complete the
5694          * delalloc io.
5695          */
5696         if (!test_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5697                       &BTRFS_I(inode)->runtime_flags)) {
5698                 nr_extents++;
5699                 extra_reserve = 1;
5700         }
5701
5702         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
5703         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
5704         csum_bytes = BTRFS_I(inode)->csum_bytes;
5705         spin_unlock(&BTRFS_I(inode)->lock);
5706
5707         if (root->fs_info->quota_enabled) {
5708                 ret = btrfs_qgroup_reserve_meta(root,
5709                                 nr_extents * root->nodesize);
5710                 if (ret)
5711                         goto out_fail;
5712         }
5713
5714         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
5715         if (unlikely(ret)) {
5716                 btrfs_qgroup_free_meta(root, nr_extents * root->nodesize);
5717                 goto out_fail;
5718         }
5719
5720         spin_lock(&BTRFS_I(inode)->lock);
5721         if (extra_reserve) {
5722                 set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5723                         &BTRFS_I(inode)->runtime_flags);
5724                 nr_extents--;
5725         }
5726         BTRFS_I(inode)->reserved_extents += nr_extents;
5727         spin_unlock(&BTRFS_I(inode)->lock);
5728
5729         if (delalloc_lock)
5730                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5731
5732         if (to_reserve)
5733                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5734                                               btrfs_ino(inode), to_reserve, 1);
5735         block_rsv_add_bytes(block_rsv, to_reserve, 1);
5736
5737         return 0;
5738
5739 out_fail:
5740         spin_lock(&BTRFS_I(inode)->lock);
5741         dropped = drop_outstanding_extent(inode, num_bytes);
5742         /*
5743          * If the inodes csum_bytes is the same as the original
5744          * csum_bytes then we know we haven't raced with any free()ers
5745          * so we can just reduce our inodes csum bytes and carry on.
5746          */
5747         if (BTRFS_I(inode)->csum_bytes == csum_bytes) {
5748                 calc_csum_metadata_size(inode, num_bytes, 0);
5749         } else {
5750                 u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes;
5751                 u64 bytes;
5752
5753                 /*
5754                  * This is tricky, but first we need to figure out how much we
5755                  * free'd from any free-ers that occured during this
5756                  * reservation, so we reset ->csum_bytes to the csum_bytes
5757                  * before we dropped our lock, and then call the free for the
5758                  * number of bytes that were freed while we were trying our
5759                  * reservation.
5760                  */
5761                 bytes = csum_bytes - BTRFS_I(inode)->csum_bytes;
5762                 BTRFS_I(inode)->csum_bytes = csum_bytes;
5763                 to_free = calc_csum_metadata_size(inode, bytes, 0);
5764
5765
5766                 /*
5767                  * Now we need to see how much we would have freed had we not
5768                  * been making this reservation and our ->csum_bytes were not
5769                  * artificially inflated.
5770                  */
5771                 BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes;
5772                 bytes = csum_bytes - orig_csum_bytes;
5773                 bytes = calc_csum_metadata_size(inode, bytes, 0);
5774
5775                 /*
5776                  * Now reset ->csum_bytes to what it should be.  If bytes is
5777                  * more than to_free then we would have free'd more space had we
5778                  * not had an artificially high ->csum_bytes, so we need to free
5779                  * the remainder.  If bytes is the same or less then we don't
5780                  * need to do anything, the other free-ers did the correct
5781                  * thing.
5782                  */
5783                 BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes;
5784                 if (bytes > to_free)
5785                         to_free = bytes - to_free;
5786                 else
5787                         to_free = 0;
5788         }
5789         spin_unlock(&BTRFS_I(inode)->lock);
5790         if (dropped)
5791                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5792
5793         if (to_free) {
5794                 btrfs_block_rsv_release(root, block_rsv, to_free);
5795                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5796                                               btrfs_ino(inode), to_free, 0);
5797         }
5798         if (delalloc_lock)
5799                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5800         return ret;
5801 }
5802
5803 /**
5804  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
5805  * @inode: the inode to release the reservation for
5806  * @num_bytes: the number of bytes we're releasing
5807  *
5808  * This will release the metadata reservation for an inode.  This can be called
5809  * once we complete IO for a given set of bytes to release their metadata
5810  * reservations.
5811  */
5812 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
5813 {
5814         struct btrfs_root *root = BTRFS_I(inode)->root;
5815         u64 to_free = 0;
5816         unsigned dropped;
5817
5818         num_bytes = ALIGN(num_bytes, root->sectorsize);
5819         spin_lock(&BTRFS_I(inode)->lock);
5820         dropped = drop_outstanding_extent(inode, num_bytes);
5821
5822         if (num_bytes)
5823                 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
5824         spin_unlock(&BTRFS_I(inode)->lock);
5825         if (dropped > 0)
5826                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5827
5828         if (btrfs_test_is_dummy_root(root))
5829                 return;
5830
5831         trace_btrfs_space_reservation(root->fs_info, "delalloc",
5832                                       btrfs_ino(inode), to_free, 0);
5833
5834         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
5835                                 to_free);
5836 }
5837
5838 /**
5839  * btrfs_delalloc_reserve_space - reserve data and metadata space for
5840  * delalloc
5841  * @inode: inode we're writing to
5842  * @start: start range we are writing to
5843  * @len: how long the range we are writing to
5844  *
5845  * TODO: This function will finally replace old btrfs_delalloc_reserve_space()
5846  *
5847  * This will do the following things
5848  *
5849  * o reserve space in data space info for num bytes
5850  *   and reserve precious corresponding qgroup space
5851  *   (Done in check_data_free_space)
5852  *
5853  * o reserve space for metadata space, based on the number of outstanding
5854  *   extents and how much csums will be needed
5855  *   also reserve metadata space in a per root over-reserve method.
5856  * o add to the inodes->delalloc_bytes
5857  * o add it to the fs_info's delalloc inodes list.
5858  *   (Above 3 all done in delalloc_reserve_metadata)
5859  *
5860  * Return 0 for success
5861  * Return <0 for error(-ENOSPC or -EQUOT)
5862  */
5863 int btrfs_delalloc_reserve_space(struct inode *inode, u64 start, u64 len)
5864 {
5865         int ret;
5866
5867         ret = btrfs_check_data_free_space(inode, start, len);
5868         if (ret < 0)
5869                 return ret;
5870         ret = btrfs_delalloc_reserve_metadata(inode, len);
5871         if (ret < 0)
5872                 btrfs_free_reserved_data_space(inode, start, len);
5873         return ret;
5874 }
5875
5876 /**
5877  * btrfs_delalloc_release_space - release data and metadata space for delalloc
5878  * @inode: inode we're releasing space for
5879  * @start: start position of the space already reserved
5880  * @len: the len of the space already reserved
5881  *
5882  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
5883  * called in the case that we don't need the metadata AND data reservations
5884  * anymore.  So if there is an error or we insert an inline extent.
5885  *
5886  * This function will release the metadata space that was not used and will
5887  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
5888  * list if there are no delalloc bytes left.
5889  * Also it will handle the qgroup reserved space.
5890  */
5891 void btrfs_delalloc_release_space(struct inode *inode, u64 start, u64 len)
5892 {
5893         btrfs_delalloc_release_metadata(inode, len);
5894         btrfs_free_reserved_data_space(inode, start, len);
5895 }
5896
5897 static int update_block_group(struct btrfs_trans_handle *trans,
5898                               struct btrfs_root *root, u64 bytenr,
5899                               u64 num_bytes, int alloc)
5900 {
5901         struct btrfs_block_group_cache *cache = NULL;
5902         struct btrfs_fs_info *info = root->fs_info;
5903         u64 total = num_bytes;
5904         u64 old_val;
5905         u64 byte_in_group;
5906         int factor;
5907
5908         /* block accounting for super block */
5909         spin_lock(&info->delalloc_root_lock);
5910         old_val = btrfs_super_bytes_used(info->super_copy);
5911         if (alloc)
5912                 old_val += num_bytes;
5913         else
5914                 old_val -= num_bytes;
5915         btrfs_set_super_bytes_used(info->super_copy, old_val);
5916         spin_unlock(&info->delalloc_root_lock);
5917
5918         while (total) {
5919                 cache = btrfs_lookup_block_group(info, bytenr);
5920                 if (!cache)
5921                         return -ENOENT;
5922                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
5923                                     BTRFS_BLOCK_GROUP_RAID1 |
5924                                     BTRFS_BLOCK_GROUP_RAID10))
5925                         factor = 2;
5926                 else
5927                         factor = 1;
5928                 /*
5929                  * If this block group has free space cache written out, we
5930                  * need to make sure to load it if we are removing space.  This
5931                  * is because we need the unpinning stage to actually add the
5932                  * space back to the block group, otherwise we will leak space.
5933                  */
5934                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
5935                         cache_block_group(cache, 1);
5936
5937                 byte_in_group = bytenr - cache->key.objectid;
5938                 WARN_ON(byte_in_group > cache->key.offset);
5939
5940                 spin_lock(&cache->space_info->lock);
5941                 spin_lock(&cache->lock);
5942
5943                 if (btrfs_test_opt(root, SPACE_CACHE) &&
5944                     cache->disk_cache_state < BTRFS_DC_CLEAR)
5945                         cache->disk_cache_state = BTRFS_DC_CLEAR;
5946
5947                 old_val = btrfs_block_group_used(&cache->item);
5948                 num_bytes = min(total, cache->key.offset - byte_in_group);
5949                 if (alloc) {
5950                         old_val += num_bytes;
5951                         btrfs_set_block_group_used(&cache->item, old_val);
5952                         cache->reserved -= num_bytes;
5953                         cache->space_info->bytes_reserved -= num_bytes;
5954                         cache->space_info->bytes_used += num_bytes;
5955                         cache->space_info->disk_used += num_bytes * factor;
5956                         spin_unlock(&cache->lock);
5957                         spin_unlock(&cache->space_info->lock);
5958                 } else {
5959                         old_val -= num_bytes;
5960                         btrfs_set_block_group_used(&cache->item, old_val);
5961                         cache->pinned += num_bytes;
5962                         cache->space_info->bytes_pinned += num_bytes;
5963                         cache->space_info->bytes_used -= num_bytes;
5964                         cache->space_info->disk_used -= num_bytes * factor;
5965                         spin_unlock(&cache->lock);
5966                         spin_unlock(&cache->space_info->lock);
5967
5968                         set_extent_dirty(info->pinned_extents,
5969                                          bytenr, bytenr + num_bytes - 1,
5970                                          GFP_NOFS | __GFP_NOFAIL);
5971                 }
5972
5973                 spin_lock(&trans->transaction->dirty_bgs_lock);
5974                 if (list_empty(&cache->dirty_list)) {
5975                         list_add_tail(&cache->dirty_list,
5976                                       &trans->transaction->dirty_bgs);
5977                                 trans->transaction->num_dirty_bgs++;
5978                         btrfs_get_block_group(cache);
5979                 }
5980                 spin_unlock(&trans->transaction->dirty_bgs_lock);
5981
5982                 /*
5983                  * No longer have used bytes in this block group, queue it for
5984                  * deletion. We do this after adding the block group to the
5985                  * dirty list to avoid races between cleaner kthread and space
5986                  * cache writeout.
5987                  */
5988                 if (!alloc && old_val == 0) {
5989                         spin_lock(&info->unused_bgs_lock);
5990                         if (list_empty(&cache->bg_list)) {
5991                                 btrfs_get_block_group(cache);
5992                                 list_add_tail(&cache->bg_list,
5993                                               &info->unused_bgs);
5994                         }
5995                         spin_unlock(&info->unused_bgs_lock);
5996                 }
5997
5998                 btrfs_put_block_group(cache);
5999                 total -= num_bytes;
6000                 bytenr += num_bytes;
6001         }
6002         return 0;
6003 }
6004
6005 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
6006 {
6007         struct btrfs_block_group_cache *cache;
6008         u64 bytenr;
6009
6010         spin_lock(&root->fs_info->block_group_cache_lock);
6011         bytenr = root->fs_info->first_logical_byte;
6012         spin_unlock(&root->fs_info->block_group_cache_lock);
6013
6014         if (bytenr < (u64)-1)
6015                 return bytenr;
6016
6017         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
6018         if (!cache)
6019                 return 0;
6020
6021         bytenr = cache->key.objectid;
6022         btrfs_put_block_group(cache);
6023
6024         return bytenr;
6025 }
6026
6027 static int pin_down_extent(struct btrfs_root *root,
6028                            struct btrfs_block_group_cache *cache,
6029                            u64 bytenr, u64 num_bytes, int reserved)
6030 {
6031         spin_lock(&cache->space_info->lock);
6032         spin_lock(&cache->lock);
6033         cache->pinned += num_bytes;
6034         cache->space_info->bytes_pinned += num_bytes;
6035         if (reserved) {
6036                 cache->reserved -= num_bytes;
6037                 cache->space_info->bytes_reserved -= num_bytes;
6038         }
6039         spin_unlock(&cache->lock);
6040         spin_unlock(&cache->space_info->lock);
6041
6042         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
6043                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
6044         if (reserved)
6045                 trace_btrfs_reserved_extent_free(root, bytenr, num_bytes);
6046         return 0;
6047 }
6048
6049 /*
6050  * this function must be called within transaction
6051  */
6052 int btrfs_pin_extent(struct btrfs_root *root,
6053                      u64 bytenr, u64 num_bytes, int reserved)
6054 {
6055         struct btrfs_block_group_cache *cache;
6056
6057         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
6058         BUG_ON(!cache); /* Logic error */
6059
6060         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
6061
6062         btrfs_put_block_group(cache);
6063         return 0;
6064 }
6065
6066 /*
6067  * this function must be called within transaction
6068  */
6069 int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
6070                                     u64 bytenr, u64 num_bytes)
6071 {
6072         struct btrfs_block_group_cache *cache;
6073         int ret;
6074
6075         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
6076         if (!cache)
6077                 return -EINVAL;
6078
6079         /*
6080          * pull in the free space cache (if any) so that our pin
6081          * removes the free space from the cache.  We have load_only set
6082          * to one because the slow code to read in the free extents does check
6083          * the pinned extents.
6084          */
6085         cache_block_group(cache, 1);
6086
6087         pin_down_extent(root, cache, bytenr, num_bytes, 0);
6088
6089         /* remove us from the free space cache (if we're there at all) */
6090         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
6091         btrfs_put_block_group(cache);
6092         return ret;
6093 }
6094
6095 static int __exclude_logged_extent(struct btrfs_root *root, u64 start, u64 num_bytes)
6096 {
6097         int ret;
6098         struct btrfs_block_group_cache *block_group;
6099         struct btrfs_caching_control *caching_ctl;
6100
6101         block_group = btrfs_lookup_block_group(root->fs_info, start);
6102         if (!block_group)
6103                 return -EINVAL;
6104
6105         cache_block_group(block_group, 0);
6106         caching_ctl = get_caching_control(block_group);
6107
6108         if (!caching_ctl) {
6109                 /* Logic error */
6110                 BUG_ON(!block_group_cache_done(block_group));
6111                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
6112         } else {
6113                 mutex_lock(&caching_ctl->mutex);
6114
6115                 if (start >= caching_ctl->progress) {
6116                         ret = add_excluded_extent(root, start, num_bytes);
6117                 } else if (start + num_bytes <= caching_ctl->progress) {
6118                         ret = btrfs_remove_free_space(block_group,
6119                                                       start, num_bytes);
6120                 } else {
6121                         num_bytes = caching_ctl->progress - start;
6122                         ret = btrfs_remove_free_space(block_group,
6123                                                       start, num_bytes);
6124                         if (ret)
6125                                 goto out_lock;
6126
6127                         num_bytes = (start + num_bytes) -
6128                                 caching_ctl->progress;
6129                         start = caching_ctl->progress;
6130                         ret = add_excluded_extent(root, start, num_bytes);
6131                 }
6132 out_lock:
6133                 mutex_unlock(&caching_ctl->mutex);
6134                 put_caching_control(caching_ctl);
6135         }
6136         btrfs_put_block_group(block_group);
6137         return ret;
6138 }
6139
6140 int btrfs_exclude_logged_extents(struct btrfs_root *log,
6141                                  struct extent_buffer *eb)
6142 {
6143         struct btrfs_file_extent_item *item;
6144         struct btrfs_key key;
6145         int found_type;
6146         int i;
6147
6148         if (!btrfs_fs_incompat(log->fs_info, MIXED_GROUPS))
6149                 return 0;
6150
6151         for (i = 0; i < btrfs_header_nritems(eb); i++) {
6152                 btrfs_item_key_to_cpu(eb, &key, i);
6153                 if (key.type != BTRFS_EXTENT_DATA_KEY)
6154                         continue;
6155                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
6156                 found_type = btrfs_file_extent_type(eb, item);
6157                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
6158                         continue;
6159                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
6160                         continue;
6161                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
6162                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
6163                 __exclude_logged_extent(log, key.objectid, key.offset);
6164         }
6165
6166         return 0;
6167 }
6168
6169 /**
6170  * btrfs_update_reserved_bytes - update the block_group and space info counters
6171  * @cache:      The cache we are manipulating
6172  * @num_bytes:  The number of bytes in question
6173  * @reserve:    One of the reservation enums
6174  * @delalloc:   The blocks are allocated for the delalloc write
6175  *
6176  * This is called by the allocator when it reserves space, or by somebody who is
6177  * freeing space that was never actually used on disk.  For example if you
6178  * reserve some space for a new leaf in transaction A and before transaction A
6179  * commits you free that leaf, you call this with reserve set to 0 in order to
6180  * clear the reservation.
6181  *
6182  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
6183  * ENOSPC accounting.  For data we handle the reservation through clearing the
6184  * delalloc bits in the io_tree.  We have to do this since we could end up
6185  * allocating less disk space for the amount of data we have reserved in the
6186  * case of compression.
6187  *
6188  * If this is a reservation and the block group has become read only we cannot
6189  * make the reservation and return -EAGAIN, otherwise this function always
6190  * succeeds.
6191  */
6192 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
6193                                        u64 num_bytes, int reserve, int delalloc)
6194 {
6195         struct btrfs_space_info *space_info = cache->space_info;
6196         int ret = 0;
6197
6198         spin_lock(&space_info->lock);
6199         spin_lock(&cache->lock);
6200         if (reserve != RESERVE_FREE) {
6201                 if (cache->ro) {
6202                         ret = -EAGAIN;
6203                 } else {
6204                         cache->reserved += num_bytes;
6205                         space_info->bytes_reserved += num_bytes;
6206                         if (reserve == RESERVE_ALLOC) {
6207                                 trace_btrfs_space_reservation(cache->fs_info,
6208                                                 "space_info", space_info->flags,
6209                                                 num_bytes, 0);
6210                                 space_info->bytes_may_use -= num_bytes;
6211                         }
6212
6213                         if (delalloc)
6214                                 cache->delalloc_bytes += num_bytes;
6215                 }
6216         } else {
6217                 if (cache->ro)
6218                         space_info->bytes_readonly += num_bytes;
6219                 cache->reserved -= num_bytes;
6220                 space_info->bytes_reserved -= num_bytes;
6221
6222                 if (delalloc)
6223                         cache->delalloc_bytes -= num_bytes;
6224         }
6225         spin_unlock(&cache->lock);
6226         spin_unlock(&space_info->lock);
6227         return ret;
6228 }
6229
6230 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
6231                                 struct btrfs_root *root)
6232 {
6233         struct btrfs_fs_info *fs_info = root->fs_info;
6234         struct btrfs_caching_control *next;
6235         struct btrfs_caching_control *caching_ctl;
6236         struct btrfs_block_group_cache *cache;
6237
6238         down_write(&fs_info->commit_root_sem);
6239
6240         list_for_each_entry_safe(caching_ctl, next,
6241                                  &fs_info->caching_block_groups, list) {
6242                 cache = caching_ctl->block_group;
6243                 if (block_group_cache_done(cache)) {
6244                         cache->last_byte_to_unpin = (u64)-1;
6245                         list_del_init(&caching_ctl->list);
6246                         put_caching_control(caching_ctl);
6247                 } else {
6248                         cache->last_byte_to_unpin = caching_ctl->progress;
6249                 }
6250         }
6251
6252         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6253                 fs_info->pinned_extents = &fs_info->freed_extents[1];
6254         else
6255                 fs_info->pinned_extents = &fs_info->freed_extents[0];
6256
6257         up_write(&fs_info->commit_root_sem);
6258
6259         update_global_block_rsv(fs_info);
6260 }
6261
6262 /*
6263  * Returns the free cluster for the given space info and sets empty_cluster to
6264  * what it should be based on the mount options.
6265  */
6266 static struct btrfs_free_cluster *
6267 fetch_cluster_info(struct btrfs_root *root, struct btrfs_space_info *space_info,
6268                    u64 *empty_cluster)
6269 {
6270         struct btrfs_free_cluster *ret = NULL;
6271         bool ssd = btrfs_test_opt(root, SSD);
6272
6273         *empty_cluster = 0;
6274         if (btrfs_mixed_space_info(space_info))
6275                 return ret;
6276
6277         if (ssd)
6278                 *empty_cluster = SZ_2M;
6279         if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
6280                 ret = &root->fs_info->meta_alloc_cluster;
6281                 if (!ssd)
6282                         *empty_cluster = SZ_64K;
6283         } else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) && ssd) {
6284                 ret = &root->fs_info->data_alloc_cluster;
6285         }
6286
6287         return ret;
6288 }
6289
6290 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end,
6291                               const bool return_free_space)
6292 {
6293         struct btrfs_fs_info *fs_info = root->fs_info;
6294         struct btrfs_block_group_cache *cache = NULL;
6295         struct btrfs_space_info *space_info;
6296         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
6297         struct btrfs_free_cluster *cluster = NULL;
6298         u64 len;
6299         u64 total_unpinned = 0;
6300         u64 empty_cluster = 0;
6301         bool readonly;
6302
6303         while (start <= end) {
6304                 readonly = false;
6305                 if (!cache ||
6306                     start >= cache->key.objectid + cache->key.offset) {
6307                         if (cache)
6308                                 btrfs_put_block_group(cache);
6309                         total_unpinned = 0;
6310                         cache = btrfs_lookup_block_group(fs_info, start);
6311                         BUG_ON(!cache); /* Logic error */
6312
6313                         cluster = fetch_cluster_info(root,
6314                                                      cache->space_info,
6315                                                      &empty_cluster);
6316                         empty_cluster <<= 1;
6317                 }
6318
6319                 len = cache->key.objectid + cache->key.offset - start;
6320                 len = min(len, end + 1 - start);
6321
6322                 if (start < cache->last_byte_to_unpin) {
6323                         len = min(len, cache->last_byte_to_unpin - start);
6324                         if (return_free_space)
6325                                 btrfs_add_free_space(cache, start, len);
6326                 }
6327
6328                 start += len;
6329                 total_unpinned += len;
6330                 space_info = cache->space_info;
6331
6332                 /*
6333                  * If this space cluster has been marked as fragmented and we've
6334                  * unpinned enough in this block group to potentially allow a
6335                  * cluster to be created inside of it go ahead and clear the
6336                  * fragmented check.
6337                  */
6338                 if (cluster && cluster->fragmented &&
6339                     total_unpinned > empty_cluster) {
6340                         spin_lock(&cluster->lock);
6341                         cluster->fragmented = 0;
6342                         spin_unlock(&cluster->lock);
6343                 }
6344
6345                 spin_lock(&space_info->lock);
6346                 spin_lock(&cache->lock);
6347                 cache->pinned -= len;
6348                 space_info->bytes_pinned -= len;
6349                 space_info->max_extent_size = 0;
6350                 percpu_counter_add(&space_info->total_bytes_pinned, -len);
6351                 if (cache->ro) {
6352                         space_info->bytes_readonly += len;
6353                         readonly = true;
6354                 }
6355                 spin_unlock(&cache->lock);
6356                 if (!readonly && global_rsv->space_info == space_info) {
6357                         spin_lock(&global_rsv->lock);
6358                         if (!global_rsv->full) {
6359                                 len = min(len, global_rsv->size -
6360                                           global_rsv->reserved);
6361                                 global_rsv->reserved += len;
6362                                 space_info->bytes_may_use += len;
6363                                 if (global_rsv->reserved >= global_rsv->size)
6364                                         global_rsv->full = 1;
6365                         }
6366                         spin_unlock(&global_rsv->lock);
6367                 }
6368                 spin_unlock(&space_info->lock);
6369         }
6370
6371         if (cache)
6372                 btrfs_put_block_group(cache);
6373         return 0;
6374 }
6375
6376 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
6377                                struct btrfs_root *root)
6378 {
6379         struct btrfs_fs_info *fs_info = root->fs_info;
6380         struct btrfs_block_group_cache *block_group, *tmp;
6381         struct list_head *deleted_bgs;
6382         struct extent_io_tree *unpin;
6383         u64 start;
6384         u64 end;
6385         int ret;
6386
6387         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6388                 unpin = &fs_info->freed_extents[1];
6389         else
6390                 unpin = &fs_info->freed_extents[0];
6391
6392         while (!trans->aborted) {
6393                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
6394                 ret = find_first_extent_bit(unpin, 0, &start, &end,
6395                                             EXTENT_DIRTY, NULL);
6396                 if (ret) {
6397                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6398                         break;
6399                 }
6400
6401                 if (btrfs_test_opt(root, DISCARD))
6402                         ret = btrfs_discard_extent(root, start,
6403                                                    end + 1 - start, NULL);
6404
6405                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
6406                 unpin_extent_range(root, start, end, true);
6407                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6408                 cond_resched();
6409         }
6410
6411         /*
6412          * Transaction is finished.  We don't need the lock anymore.  We
6413          * do need to clean up the block groups in case of a transaction
6414          * abort.
6415          */
6416         deleted_bgs = &trans->transaction->deleted_bgs;
6417         list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
6418                 u64 trimmed = 0;
6419
6420                 ret = -EROFS;
6421                 if (!trans->aborted)
6422                         ret = btrfs_discard_extent(root,
6423                                                    block_group->key.objectid,
6424                                                    block_group->key.offset,
6425                                                    &trimmed);
6426
6427                 list_del_init(&block_group->bg_list);
6428                 btrfs_put_block_group_trimming(block_group);
6429                 btrfs_put_block_group(block_group);
6430
6431                 if (ret) {
6432                         const char *errstr = btrfs_decode_error(ret);
6433                         btrfs_warn(fs_info,
6434                                    "Discard failed while removing blockgroup: errno=%d %s\n",
6435                                    ret, errstr);
6436                 }
6437         }
6438
6439         return 0;
6440 }
6441
6442 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, u64 num_bytes,
6443                              u64 owner, u64 root_objectid)
6444 {
6445         struct btrfs_space_info *space_info;
6446         u64 flags;
6447
6448         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6449                 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
6450                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
6451                 else
6452                         flags = BTRFS_BLOCK_GROUP_METADATA;
6453         } else {
6454                 flags = BTRFS_BLOCK_GROUP_DATA;
6455         }
6456
6457         space_info = __find_space_info(fs_info, flags);
6458         BUG_ON(!space_info); /* Logic bug */
6459         percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
6460 }
6461
6462
6463 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
6464                                 struct btrfs_root *root,
6465                                 struct btrfs_delayed_ref_node *node, u64 parent,
6466                                 u64 root_objectid, u64 owner_objectid,
6467                                 u64 owner_offset, int refs_to_drop,
6468                                 struct btrfs_delayed_extent_op *extent_op)
6469 {
6470         struct btrfs_key key;
6471         struct btrfs_path *path;
6472         struct btrfs_fs_info *info = root->fs_info;
6473         struct btrfs_root *extent_root = info->extent_root;
6474         struct extent_buffer *leaf;
6475         struct btrfs_extent_item *ei;
6476         struct btrfs_extent_inline_ref *iref;
6477         int ret;
6478         int is_data;
6479         int extent_slot = 0;
6480         int found_extent = 0;
6481         int num_to_del = 1;
6482         u32 item_size;
6483         u64 refs;
6484         u64 bytenr = node->bytenr;
6485         u64 num_bytes = node->num_bytes;
6486         int last_ref = 0;
6487         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6488                                                  SKINNY_METADATA);
6489
6490         path = btrfs_alloc_path();
6491         if (!path)
6492                 return -ENOMEM;
6493
6494         path->reada = READA_FORWARD;
6495         path->leave_spinning = 1;
6496
6497         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
6498         BUG_ON(!is_data && refs_to_drop != 1);
6499
6500         if (is_data)
6501                 skinny_metadata = 0;
6502
6503         ret = lookup_extent_backref(trans, extent_root, path, &iref,
6504                                     bytenr, num_bytes, parent,
6505                                     root_objectid, owner_objectid,
6506                                     owner_offset);
6507         if (ret == 0) {
6508                 extent_slot = path->slots[0];
6509                 while (extent_slot >= 0) {
6510                         btrfs_item_key_to_cpu(path->nodes[0], &key,
6511                                               extent_slot);
6512                         if (key.objectid != bytenr)
6513                                 break;
6514                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
6515                             key.offset == num_bytes) {
6516                                 found_extent = 1;
6517                                 break;
6518                         }
6519                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
6520                             key.offset == owner_objectid) {
6521                                 found_extent = 1;
6522                                 break;
6523                         }
6524                         if (path->slots[0] - extent_slot > 5)
6525                                 break;
6526                         extent_slot--;
6527                 }
6528 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6529                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
6530                 if (found_extent && item_size < sizeof(*ei))
6531                         found_extent = 0;
6532 #endif
6533                 if (!found_extent) {
6534                         BUG_ON(iref);
6535                         ret = remove_extent_backref(trans, extent_root, path,
6536                                                     NULL, refs_to_drop,
6537                                                     is_data, &last_ref);
6538                         if (ret) {
6539                                 btrfs_abort_transaction(trans, extent_root, ret);
6540                                 goto out;
6541                         }
6542                         btrfs_release_path(path);
6543                         path->leave_spinning = 1;
6544
6545                         key.objectid = bytenr;
6546                         key.type = BTRFS_EXTENT_ITEM_KEY;
6547                         key.offset = num_bytes;
6548
6549                         if (!is_data && skinny_metadata) {
6550                                 key.type = BTRFS_METADATA_ITEM_KEY;
6551                                 key.offset = owner_objectid;
6552                         }
6553
6554                         ret = btrfs_search_slot(trans, extent_root,
6555                                                 &key, path, -1, 1);
6556                         if (ret > 0 && skinny_metadata && path->slots[0]) {
6557                                 /*
6558                                  * Couldn't find our skinny metadata item,
6559                                  * see if we have ye olde extent item.
6560                                  */
6561                                 path->slots[0]--;
6562                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
6563                                                       path->slots[0]);
6564                                 if (key.objectid == bytenr &&
6565                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
6566                                     key.offset == num_bytes)
6567                                         ret = 0;
6568                         }
6569
6570                         if (ret > 0 && skinny_metadata) {
6571                                 skinny_metadata = false;
6572                                 key.objectid = bytenr;
6573                                 key.type = BTRFS_EXTENT_ITEM_KEY;
6574                                 key.offset = num_bytes;
6575                                 btrfs_release_path(path);
6576                                 ret = btrfs_search_slot(trans, extent_root,
6577                                                         &key, path, -1, 1);
6578                         }
6579
6580                         if (ret) {
6581                                 btrfs_err(info, "umm, got %d back from search, was looking for %llu",
6582                                         ret, bytenr);
6583                                 if (ret > 0)
6584                                         btrfs_print_leaf(extent_root,
6585                                                          path->nodes[0]);
6586                         }
6587                         if (ret < 0) {
6588                                 btrfs_abort_transaction(trans, extent_root, ret);
6589                                 goto out;
6590                         }
6591                         extent_slot = path->slots[0];
6592                 }
6593         } else if (WARN_ON(ret == -ENOENT)) {
6594                 btrfs_print_leaf(extent_root, path->nodes[0]);
6595                 btrfs_err(info,
6596                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
6597                         bytenr, parent, root_objectid, owner_objectid,
6598                         owner_offset);
6599                 btrfs_abort_transaction(trans, extent_root, ret);
6600                 goto out;
6601         } else {
6602                 btrfs_abort_transaction(trans, extent_root, ret);
6603                 goto out;
6604         }
6605
6606         leaf = path->nodes[0];
6607         item_size = btrfs_item_size_nr(leaf, extent_slot);
6608 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6609         if (item_size < sizeof(*ei)) {
6610                 BUG_ON(found_extent || extent_slot != path->slots[0]);
6611                 ret = convert_extent_item_v0(trans, extent_root, path,
6612                                              owner_objectid, 0);
6613                 if (ret < 0) {
6614                         btrfs_abort_transaction(trans, extent_root, ret);
6615                         goto out;
6616                 }
6617
6618                 btrfs_release_path(path);
6619                 path->leave_spinning = 1;
6620
6621                 key.objectid = bytenr;
6622                 key.type = BTRFS_EXTENT_ITEM_KEY;
6623                 key.offset = num_bytes;
6624
6625                 ret = btrfs_search_slot(trans, extent_root, &key, path,
6626                                         -1, 1);
6627                 if (ret) {
6628                         btrfs_err(info, "umm, got %d back from search, was looking for %llu",
6629                                 ret, bytenr);
6630                         btrfs_print_leaf(extent_root, path->nodes[0]);
6631                 }
6632                 if (ret < 0) {
6633                         btrfs_abort_transaction(trans, extent_root, ret);
6634                         goto out;
6635                 }
6636
6637                 extent_slot = path->slots[0];
6638                 leaf = path->nodes[0];
6639                 item_size = btrfs_item_size_nr(leaf, extent_slot);
6640         }
6641 #endif
6642         BUG_ON(item_size < sizeof(*ei));
6643         ei = btrfs_item_ptr(leaf, extent_slot,
6644                             struct btrfs_extent_item);
6645         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
6646             key.type == BTRFS_EXTENT_ITEM_KEY) {
6647                 struct btrfs_tree_block_info *bi;
6648                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
6649                 bi = (struct btrfs_tree_block_info *)(ei + 1);
6650                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
6651         }
6652
6653         refs = btrfs_extent_refs(leaf, ei);
6654         if (refs < refs_to_drop) {
6655                 btrfs_err(info, "trying to drop %d refs but we only have %Lu "
6656                           "for bytenr %Lu", refs_to_drop, refs, bytenr);
6657                 ret = -EINVAL;
6658                 btrfs_abort_transaction(trans, extent_root, ret);
6659                 goto out;
6660         }
6661         refs -= refs_to_drop;
6662
6663         if (refs > 0) {
6664                 if (extent_op)
6665                         __run_delayed_extent_op(extent_op, leaf, ei);
6666                 /*
6667                  * In the case of inline back ref, reference count will
6668                  * be updated by remove_extent_backref
6669                  */
6670                 if (iref) {
6671                         BUG_ON(!found_extent);
6672                 } else {
6673                         btrfs_set_extent_refs(leaf, ei, refs);
6674                         btrfs_mark_buffer_dirty(leaf);
6675                 }
6676                 if (found_extent) {
6677                         ret = remove_extent_backref(trans, extent_root, path,
6678                                                     iref, refs_to_drop,
6679                                                     is_data, &last_ref);
6680                         if (ret) {
6681                                 btrfs_abort_transaction(trans, extent_root, ret);
6682                                 goto out;
6683                         }
6684                 }
6685                 add_pinned_bytes(root->fs_info, -num_bytes, owner_objectid,
6686                                  root_objectid);
6687         } else {
6688                 if (found_extent) {
6689                         BUG_ON(is_data && refs_to_drop !=
6690                                extent_data_ref_count(path, iref));
6691                         if (iref) {
6692                                 BUG_ON(path->slots[0] != extent_slot);
6693                         } else {
6694                                 BUG_ON(path->slots[0] != extent_slot + 1);
6695                                 path->slots[0] = extent_slot;
6696                                 num_to_del = 2;
6697                         }
6698                 }
6699
6700                 last_ref = 1;
6701                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
6702                                       num_to_del);
6703                 if (ret) {
6704                         btrfs_abort_transaction(trans, extent_root, ret);
6705                         goto out;
6706                 }
6707                 btrfs_release_path(path);
6708
6709                 if (is_data) {
6710                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
6711                         if (ret) {
6712                                 btrfs_abort_transaction(trans, extent_root, ret);
6713                                 goto out;
6714                         }
6715                 }
6716
6717                 ret = add_to_free_space_tree(trans, root->fs_info, bytenr,
6718                                              num_bytes);
6719                 if (ret) {
6720                         btrfs_abort_transaction(trans, extent_root, ret);
6721                         goto out;
6722                 }
6723
6724                 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
6725                 if (ret) {
6726                         btrfs_abort_transaction(trans, extent_root, ret);
6727                         goto out;
6728                 }
6729         }
6730         btrfs_release_path(path);
6731
6732 out:
6733         btrfs_free_path(path);
6734         return ret;
6735 }
6736
6737 /*
6738  * when we free an block, it is possible (and likely) that we free the last
6739  * delayed ref for that extent as well.  This searches the delayed ref tree for
6740  * a given extent, and if there are no other delayed refs to be processed, it
6741  * removes it from the tree.
6742  */
6743 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
6744                                       struct btrfs_root *root, u64 bytenr)
6745 {
6746         struct btrfs_delayed_ref_head *head;
6747         struct btrfs_delayed_ref_root *delayed_refs;
6748         int ret = 0;
6749
6750         delayed_refs = &trans->transaction->delayed_refs;
6751         spin_lock(&delayed_refs->lock);
6752         head = btrfs_find_delayed_ref_head(trans, bytenr);
6753         if (!head)
6754                 goto out_delayed_unlock;
6755
6756         spin_lock(&head->lock);
6757         if (!list_empty(&head->ref_list))
6758                 goto out;
6759
6760         if (head->extent_op) {
6761                 if (!head->must_insert_reserved)
6762                         goto out;
6763                 btrfs_free_delayed_extent_op(head->extent_op);
6764                 head->extent_op = NULL;
6765         }
6766
6767         /*
6768          * waiting for the lock here would deadlock.  If someone else has it
6769          * locked they are already in the process of dropping it anyway
6770          */
6771         if (!mutex_trylock(&head->mutex))
6772                 goto out;
6773
6774         /*
6775          * at this point we have a head with no other entries.  Go
6776          * ahead and process it.
6777          */
6778         head->node.in_tree = 0;
6779         rb_erase(&head->href_node, &delayed_refs->href_root);
6780
6781         atomic_dec(&delayed_refs->num_entries);
6782
6783         /*
6784          * we don't take a ref on the node because we're removing it from the
6785          * tree, so we just steal the ref the tree was holding.
6786          */
6787         delayed_refs->num_heads--;
6788         if (head->processing == 0)
6789                 delayed_refs->num_heads_ready--;
6790         head->processing = 0;
6791         spin_unlock(&head->lock);
6792         spin_unlock(&delayed_refs->lock);
6793
6794         BUG_ON(head->extent_op);
6795         if (head->must_insert_reserved)
6796                 ret = 1;
6797
6798         mutex_unlock(&head->mutex);
6799         btrfs_put_delayed_ref(&head->node);
6800         return ret;
6801 out:
6802         spin_unlock(&head->lock);
6803
6804 out_delayed_unlock:
6805         spin_unlock(&delayed_refs->lock);
6806         return 0;
6807 }
6808
6809 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
6810                            struct btrfs_root *root,
6811                            struct extent_buffer *buf,
6812                            u64 parent, int last_ref)
6813 {
6814         int pin = 1;
6815         int ret;
6816
6817         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
6818                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
6819                                         buf->start, buf->len,
6820                                         parent, root->root_key.objectid,
6821                                         btrfs_header_level(buf),
6822                                         BTRFS_DROP_DELAYED_REF, NULL);
6823                 BUG_ON(ret); /* -ENOMEM */
6824         }
6825
6826         if (!last_ref)
6827                 return;
6828
6829         if (btrfs_header_generation(buf) == trans->transid) {
6830                 struct btrfs_block_group_cache *cache;
6831
6832                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
6833                         ret = check_ref_cleanup(trans, root, buf->start);
6834                         if (!ret)
6835                                 goto out;
6836                 }
6837
6838                 cache = btrfs_lookup_block_group(root->fs_info, buf->start);
6839
6840                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
6841                         pin_down_extent(root, cache, buf->start, buf->len, 1);
6842                         btrfs_put_block_group(cache);
6843                         goto out;
6844                 }
6845
6846                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
6847
6848                 btrfs_add_free_space(cache, buf->start, buf->len);
6849                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE, 0);
6850                 btrfs_put_block_group(cache);
6851                 trace_btrfs_reserved_extent_free(root, buf->start, buf->len);
6852                 pin = 0;
6853         }
6854 out:
6855         if (pin)
6856                 add_pinned_bytes(root->fs_info, buf->len,
6857                                  btrfs_header_level(buf),
6858                                  root->root_key.objectid);
6859
6860         /*
6861          * Deleting the buffer, clear the corrupt flag since it doesn't matter
6862          * anymore.
6863          */
6864         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
6865 }
6866
6867 /* Can return -ENOMEM */
6868 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
6869                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
6870                       u64 owner, u64 offset)
6871 {
6872         int ret;
6873         struct btrfs_fs_info *fs_info = root->fs_info;
6874
6875         if (btrfs_test_is_dummy_root(root))
6876                 return 0;
6877
6878         add_pinned_bytes(root->fs_info, num_bytes, owner, root_objectid);
6879
6880         /*
6881          * tree log blocks never actually go into the extent allocation
6882          * tree, just update pinning info and exit early.
6883          */
6884         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
6885                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
6886                 /* unlocks the pinned mutex */
6887                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
6888                 ret = 0;
6889         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6890                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
6891                                         num_bytes,
6892                                         parent, root_objectid, (int)owner,
6893                                         BTRFS_DROP_DELAYED_REF, NULL);
6894         } else {
6895                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
6896                                                 num_bytes,
6897                                                 parent, root_objectid, owner,
6898                                                 offset, 0,
6899                                                 BTRFS_DROP_DELAYED_REF, NULL);
6900         }
6901         return ret;
6902 }
6903
6904 /*
6905  * when we wait for progress in the block group caching, its because
6906  * our allocation attempt failed at least once.  So, we must sleep
6907  * and let some progress happen before we try again.
6908  *
6909  * This function will sleep at least once waiting for new free space to
6910  * show up, and then it will check the block group free space numbers
6911  * for our min num_bytes.  Another option is to have it go ahead
6912  * and look in the rbtree for a free extent of a given size, but this
6913  * is a good start.
6914  *
6915  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
6916  * any of the information in this block group.
6917  */
6918 static noinline void
6919 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
6920                                 u64 num_bytes)
6921 {
6922         struct btrfs_caching_control *caching_ctl;
6923
6924         caching_ctl = get_caching_control(cache);
6925         if (!caching_ctl)
6926                 return;
6927
6928         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
6929                    (cache->free_space_ctl->free_space >= num_bytes));
6930
6931         put_caching_control(caching_ctl);
6932 }
6933
6934 static noinline int
6935 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
6936 {
6937         struct btrfs_caching_control *caching_ctl;
6938         int ret = 0;
6939
6940         caching_ctl = get_caching_control(cache);
6941         if (!caching_ctl)
6942                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
6943
6944         wait_event(caching_ctl->wait, block_group_cache_done(cache));
6945         if (cache->cached == BTRFS_CACHE_ERROR)
6946                 ret = -EIO;
6947         put_caching_control(caching_ctl);
6948         return ret;
6949 }
6950
6951 int __get_raid_index(u64 flags)
6952 {
6953         if (flags & BTRFS_BLOCK_GROUP_RAID10)
6954                 return BTRFS_RAID_RAID10;
6955         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
6956                 return BTRFS_RAID_RAID1;
6957         else if (flags & BTRFS_BLOCK_GROUP_DUP)
6958                 return BTRFS_RAID_DUP;
6959         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
6960                 return BTRFS_RAID_RAID0;
6961         else if (flags & BTRFS_BLOCK_GROUP_RAID5)
6962                 return BTRFS_RAID_RAID5;
6963         else if (flags & BTRFS_BLOCK_GROUP_RAID6)
6964                 return BTRFS_RAID_RAID6;
6965
6966         return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
6967 }
6968
6969 int get_block_group_index(struct btrfs_block_group_cache *cache)
6970 {
6971         return __get_raid_index(cache->flags);
6972 }
6973
6974 static const char *btrfs_raid_type_names[BTRFS_NR_RAID_TYPES] = {
6975         [BTRFS_RAID_RAID10]     = "raid10",
6976         [BTRFS_RAID_RAID1]      = "raid1",
6977         [BTRFS_RAID_DUP]        = "dup",
6978         [BTRFS_RAID_RAID0]      = "raid0",
6979         [BTRFS_RAID_SINGLE]     = "single",
6980         [BTRFS_RAID_RAID5]      = "raid5",
6981         [BTRFS_RAID_RAID6]      = "raid6",
6982 };
6983
6984 static const char *get_raid_name(enum btrfs_raid_types type)
6985 {
6986         if (type >= BTRFS_NR_RAID_TYPES)
6987                 return NULL;
6988
6989         return btrfs_raid_type_names[type];
6990 }
6991
6992 enum btrfs_loop_type {
6993         LOOP_CACHING_NOWAIT = 0,
6994         LOOP_CACHING_WAIT = 1,
6995         LOOP_ALLOC_CHUNK = 2,
6996         LOOP_NO_EMPTY_SIZE = 3,
6997 };
6998
6999 static inline void
7000 btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
7001                        int delalloc)
7002 {
7003         if (delalloc)
7004                 down_read(&cache->data_rwsem);
7005 }
7006
7007 static inline void
7008 btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
7009                        int delalloc)
7010 {
7011         btrfs_get_block_group(cache);
7012         if (delalloc)
7013                 down_read(&cache->data_rwsem);
7014 }
7015
7016 static struct btrfs_block_group_cache *
7017 btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
7018                    struct btrfs_free_cluster *cluster,
7019                    int delalloc)
7020 {
7021         struct btrfs_block_group_cache *used_bg;
7022         bool locked = false;
7023 again:
7024         spin_lock(&cluster->refill_lock);
7025         if (locked) {
7026                 if (used_bg == cluster->block_group)
7027                         return used_bg;
7028
7029                 up_read(&used_bg->data_rwsem);
7030                 btrfs_put_block_group(used_bg);
7031         }
7032
7033         used_bg = cluster->block_group;
7034         if (!used_bg)
7035                 return NULL;
7036
7037         if (used_bg == block_group)
7038                 return used_bg;
7039
7040         btrfs_get_block_group(used_bg);
7041
7042         if (!delalloc)
7043                 return used_bg;
7044
7045         if (down_read_trylock(&used_bg->data_rwsem))
7046                 return used_bg;
7047
7048         spin_unlock(&cluster->refill_lock);
7049         down_read(&used_bg->data_rwsem);
7050         locked = true;
7051         goto again;
7052 }
7053
7054 static inline void
7055 btrfs_release_block_group(struct btrfs_block_group_cache *cache,
7056                          int delalloc)
7057 {
7058         if (delalloc)
7059                 up_read(&cache->data_rwsem);
7060         btrfs_put_block_group(cache);
7061 }
7062
7063 /*
7064  * walks the btree of allocated extents and find a hole of a given size.
7065  * The key ins is changed to record the hole:
7066  * ins->objectid == start position
7067  * ins->flags = BTRFS_EXTENT_ITEM_KEY
7068  * ins->offset == the size of the hole.
7069  * Any available blocks before search_start are skipped.
7070  *
7071  * If there is no suitable free space, we will record the max size of
7072  * the free space extent currently.
7073  */
7074 static noinline int find_free_extent(struct btrfs_root *orig_root,
7075                                      u64 num_bytes, u64 empty_size,
7076                                      u64 hint_byte, struct btrfs_key *ins,
7077                                      u64 flags, int delalloc)
7078 {
7079         int ret = 0;
7080         struct btrfs_root *root = orig_root->fs_info->extent_root;
7081         struct btrfs_free_cluster *last_ptr = NULL;
7082         struct btrfs_block_group_cache *block_group = NULL;
7083         u64 search_start = 0;
7084         u64 max_extent_size = 0;
7085         u64 empty_cluster = 0;
7086         struct btrfs_space_info *space_info;
7087         int loop = 0;
7088         int index = __get_raid_index(flags);
7089         int alloc_type = (flags & BTRFS_BLOCK_GROUP_DATA) ?
7090                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
7091         bool failed_cluster_refill = false;
7092         bool failed_alloc = false;
7093         bool use_cluster = true;
7094         bool have_caching_bg = false;
7095         bool orig_have_caching_bg = false;
7096         bool full_search = false;
7097
7098         WARN_ON(num_bytes < root->sectorsize);
7099         ins->type = BTRFS_EXTENT_ITEM_KEY;
7100         ins->objectid = 0;
7101         ins->offset = 0;
7102
7103         trace_find_free_extent(orig_root, num_bytes, empty_size, flags);
7104
7105         space_info = __find_space_info(root->fs_info, flags);
7106         if (!space_info) {
7107                 btrfs_err(root->fs_info, "No space info for %llu", flags);
7108                 return -ENOSPC;
7109         }
7110
7111         /*
7112          * If our free space is heavily fragmented we may not be able to make
7113          * big contiguous allocations, so instead of doing the expensive search
7114          * for free space, simply return ENOSPC with our max_extent_size so we
7115          * can go ahead and search for a more manageable chunk.
7116          *
7117          * If our max_extent_size is large enough for our allocation simply
7118          * disable clustering since we will likely not be able to find enough
7119          * space to create a cluster and induce latency trying.
7120          */
7121         if (unlikely(space_info->max_extent_size)) {
7122                 spin_lock(&space_info->lock);
7123                 if (space_info->max_extent_size &&
7124                     num_bytes > space_info->max_extent_size) {
7125                         ins->offset = space_info->max_extent_size;
7126                         spin_unlock(&space_info->lock);
7127                         return -ENOSPC;
7128                 } else if (space_info->max_extent_size) {
7129                         use_cluster = false;
7130                 }
7131                 spin_unlock(&space_info->lock);
7132         }
7133
7134         last_ptr = fetch_cluster_info(orig_root, space_info, &empty_cluster);
7135         if (last_ptr) {
7136                 spin_lock(&last_ptr->lock);
7137                 if (last_ptr->block_group)
7138                         hint_byte = last_ptr->window_start;
7139                 if (last_ptr->fragmented) {
7140                         /*
7141                          * We still set window_start so we can keep track of the
7142                          * last place we found an allocation to try and save
7143                          * some time.
7144                          */
7145                         hint_byte = last_ptr->window_start;
7146                         use_cluster = false;
7147                 }
7148                 spin_unlock(&last_ptr->lock);
7149         }
7150
7151         search_start = max(search_start, first_logical_byte(root, 0));
7152         search_start = max(search_start, hint_byte);
7153         if (search_start == hint_byte) {
7154                 block_group = btrfs_lookup_block_group(root->fs_info,
7155                                                        search_start);
7156                 /*
7157                  * we don't want to use the block group if it doesn't match our
7158                  * allocation bits, or if its not cached.
7159                  *
7160                  * However if we are re-searching with an ideal block group
7161                  * picked out then we don't care that the block group is cached.
7162                  */
7163                 if (block_group && block_group_bits(block_group, flags) &&
7164                     block_group->cached != BTRFS_CACHE_NO) {
7165                         down_read(&space_info->groups_sem);
7166                         if (list_empty(&block_group->list) ||
7167                             block_group->ro) {
7168                                 /*
7169                                  * someone is removing this block group,
7170                                  * we can't jump into the have_block_group
7171                                  * target because our list pointers are not
7172                                  * valid
7173                                  */
7174                                 btrfs_put_block_group(block_group);
7175                                 up_read(&space_info->groups_sem);
7176                         } else {
7177                                 index = get_block_group_index(block_group);
7178                                 btrfs_lock_block_group(block_group, delalloc);
7179                                 goto have_block_group;
7180                         }
7181                 } else if (block_group) {
7182                         btrfs_put_block_group(block_group);
7183                 }
7184         }
7185 search:
7186         have_caching_bg = false;
7187         if (index == 0 || index == __get_raid_index(flags))
7188                 full_search = true;
7189         down_read(&space_info->groups_sem);
7190         list_for_each_entry(block_group, &space_info->block_groups[index],
7191                             list) {
7192                 u64 offset;
7193                 int cached;
7194
7195                 btrfs_grab_block_group(block_group, delalloc);
7196                 search_start = block_group->key.objectid;
7197
7198                 /*
7199                  * this can happen if we end up cycling through all the
7200                  * raid types, but we want to make sure we only allocate
7201                  * for the proper type.
7202                  */
7203                 if (!block_group_bits(block_group, flags)) {
7204                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
7205                                 BTRFS_BLOCK_GROUP_RAID1 |
7206                                 BTRFS_BLOCK_GROUP_RAID5 |
7207                                 BTRFS_BLOCK_GROUP_RAID6 |
7208                                 BTRFS_BLOCK_GROUP_RAID10;
7209
7210                         /*
7211                          * if they asked for extra copies and this block group
7212                          * doesn't provide them, bail.  This does allow us to
7213                          * fill raid0 from raid1.
7214                          */
7215                         if ((flags & extra) && !(block_group->flags & extra))
7216                                 goto loop;
7217                 }
7218
7219 have_block_group:
7220                 cached = block_group_cache_done(block_group);
7221                 if (unlikely(!cached)) {
7222                         have_caching_bg = true;
7223                         ret = cache_block_group(block_group, 0);
7224                         BUG_ON(ret < 0);
7225                         ret = 0;
7226                 }
7227
7228                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
7229                         goto loop;
7230                 if (unlikely(block_group->ro))
7231                         goto loop;
7232
7233                 /*
7234                  * Ok we want to try and use the cluster allocator, so
7235                  * lets look there
7236                  */
7237                 if (last_ptr && use_cluster) {
7238                         struct btrfs_block_group_cache *used_block_group;
7239                         unsigned long aligned_cluster;
7240                         /*
7241                          * the refill lock keeps out other
7242                          * people trying to start a new cluster
7243                          */
7244                         used_block_group = btrfs_lock_cluster(block_group,
7245                                                               last_ptr,
7246                                                               delalloc);
7247                         if (!used_block_group)
7248                                 goto refill_cluster;
7249
7250                         if (used_block_group != block_group &&
7251                             (used_block_group->ro ||
7252                              !block_group_bits(used_block_group, flags)))
7253                                 goto release_cluster;
7254
7255                         offset = btrfs_alloc_from_cluster(used_block_group,
7256                                                 last_ptr,
7257                                                 num_bytes,
7258                                                 used_block_group->key.objectid,
7259                                                 &max_extent_size);
7260                         if (offset) {
7261                                 /* we have a block, we're done */
7262                                 spin_unlock(&last_ptr->refill_lock);
7263                                 trace_btrfs_reserve_extent_cluster(root,
7264                                                 used_block_group,
7265                                                 search_start, num_bytes);
7266                                 if (used_block_group != block_group) {
7267                                         btrfs_release_block_group(block_group,
7268                                                                   delalloc);
7269                                         block_group = used_block_group;
7270                                 }
7271                                 goto checks;
7272                         }
7273
7274                         WARN_ON(last_ptr->block_group != used_block_group);
7275 release_cluster:
7276                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
7277                          * set up a new clusters, so lets just skip it
7278                          * and let the allocator find whatever block
7279                          * it can find.  If we reach this point, we
7280                          * will have tried the cluster allocator
7281                          * plenty of times and not have found
7282                          * anything, so we are likely way too
7283                          * fragmented for the clustering stuff to find
7284                          * anything.
7285                          *
7286                          * However, if the cluster is taken from the
7287                          * current block group, release the cluster
7288                          * first, so that we stand a better chance of
7289                          * succeeding in the unclustered
7290                          * allocation.  */
7291                         if (loop >= LOOP_NO_EMPTY_SIZE &&
7292                             used_block_group != block_group) {
7293                                 spin_unlock(&last_ptr->refill_lock);
7294                                 btrfs_release_block_group(used_block_group,
7295                                                           delalloc);
7296                                 goto unclustered_alloc;
7297                         }
7298
7299                         /*
7300                          * this cluster didn't work out, free it and
7301                          * start over
7302                          */
7303                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7304
7305                         if (used_block_group != block_group)
7306                                 btrfs_release_block_group(used_block_group,
7307                                                           delalloc);
7308 refill_cluster:
7309                         if (loop >= LOOP_NO_EMPTY_SIZE) {
7310                                 spin_unlock(&last_ptr->refill_lock);
7311                                 goto unclustered_alloc;
7312                         }
7313
7314                         aligned_cluster = max_t(unsigned long,
7315                                                 empty_cluster + empty_size,
7316                                               block_group->full_stripe_len);
7317
7318                         /* allocate a cluster in this block group */
7319                         ret = btrfs_find_space_cluster(root, block_group,
7320                                                        last_ptr, search_start,
7321                                                        num_bytes,
7322                                                        aligned_cluster);
7323                         if (ret == 0) {
7324                                 /*
7325                                  * now pull our allocation out of this
7326                                  * cluster
7327                                  */
7328                                 offset = btrfs_alloc_from_cluster(block_group,
7329                                                         last_ptr,
7330                                                         num_bytes,
7331                                                         search_start,
7332                                                         &max_extent_size);
7333                                 if (offset) {
7334                                         /* we found one, proceed */
7335                                         spin_unlock(&last_ptr->refill_lock);
7336                                         trace_btrfs_reserve_extent_cluster(root,
7337                                                 block_group, search_start,
7338                                                 num_bytes);
7339                                         goto checks;
7340                                 }
7341                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
7342                                    && !failed_cluster_refill) {
7343                                 spin_unlock(&last_ptr->refill_lock);
7344
7345                                 failed_cluster_refill = true;
7346                                 wait_block_group_cache_progress(block_group,
7347                                        num_bytes + empty_cluster + empty_size);
7348                                 goto have_block_group;
7349                         }
7350
7351                         /*
7352                          * at this point we either didn't find a cluster
7353                          * or we weren't able to allocate a block from our
7354                          * cluster.  Free the cluster we've been trying
7355                          * to use, and go to the next block group
7356                          */
7357                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7358                         spin_unlock(&last_ptr->refill_lock);
7359                         goto loop;
7360                 }
7361
7362 unclustered_alloc:
7363                 /*
7364                  * We are doing an unclustered alloc, set the fragmented flag so
7365                  * we don't bother trying to setup a cluster again until we get
7366                  * more space.
7367                  */
7368                 if (unlikely(last_ptr)) {
7369                         spin_lock(&last_ptr->lock);
7370                         last_ptr->fragmented = 1;
7371                         spin_unlock(&last_ptr->lock);
7372                 }
7373                 spin_lock(&block_group->free_space_ctl->tree_lock);
7374                 if (cached &&
7375                     block_group->free_space_ctl->free_space <
7376                     num_bytes + empty_cluster + empty_size) {
7377                         if (block_group->free_space_ctl->free_space >
7378                             max_extent_size)
7379                                 max_extent_size =
7380                                         block_group->free_space_ctl->free_space;
7381                         spin_unlock(&block_group->free_space_ctl->tree_lock);
7382                         goto loop;
7383                 }
7384                 spin_unlock(&block_group->free_space_ctl->tree_lock);
7385
7386                 offset = btrfs_find_space_for_alloc(block_group, search_start,
7387                                                     num_bytes, empty_size,
7388                                                     &max_extent_size);
7389                 /*
7390                  * If we didn't find a chunk, and we haven't failed on this
7391                  * block group before, and this block group is in the middle of
7392                  * caching and we are ok with waiting, then go ahead and wait
7393                  * for progress to be made, and set failed_alloc to true.
7394                  *
7395                  * If failed_alloc is true then we've already waited on this
7396                  * block group once and should move on to the next block group.
7397                  */
7398                 if (!offset && !failed_alloc && !cached &&
7399                     loop > LOOP_CACHING_NOWAIT) {
7400                         wait_block_group_cache_progress(block_group,
7401                                                 num_bytes + empty_size);
7402                         failed_alloc = true;
7403                         goto have_block_group;
7404                 } else if (!offset) {
7405                         goto loop;
7406                 }
7407 checks:
7408                 search_start = ALIGN(offset, root->stripesize);
7409
7410                 /* move on to the next group */
7411                 if (search_start + num_bytes >
7412                     block_group->key.objectid + block_group->key.offset) {
7413                         btrfs_add_free_space(block_group, offset, num_bytes);
7414                         goto loop;
7415                 }
7416
7417                 if (offset < search_start)
7418                         btrfs_add_free_space(block_group, offset,
7419                                              search_start - offset);
7420                 BUG_ON(offset > search_start);
7421
7422                 ret = btrfs_update_reserved_bytes(block_group, num_bytes,
7423                                                   alloc_type, delalloc);
7424                 if (ret == -EAGAIN) {
7425                         btrfs_add_free_space(block_group, offset, num_bytes);
7426                         goto loop;
7427                 }
7428
7429                 /* we are all good, lets return */
7430                 ins->objectid = search_start;
7431                 ins->offset = num_bytes;
7432
7433                 trace_btrfs_reserve_extent(orig_root, block_group,
7434                                            search_start, num_bytes);
7435                 btrfs_release_block_group(block_group, delalloc);
7436                 break;
7437 loop:
7438                 failed_cluster_refill = false;
7439                 failed_alloc = false;
7440                 BUG_ON(index != get_block_group_index(block_group));
7441                 btrfs_release_block_group(block_group, delalloc);
7442         }
7443         up_read(&space_info->groups_sem);
7444
7445         if ((loop == LOOP_CACHING_NOWAIT) && have_caching_bg
7446                 && !orig_have_caching_bg)
7447                 orig_have_caching_bg = true;
7448
7449         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
7450                 goto search;
7451
7452         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
7453                 goto search;
7454
7455         /*
7456          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
7457          *                      caching kthreads as we move along
7458          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
7459          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
7460          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
7461          *                      again
7462          */
7463         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
7464                 index = 0;
7465                 if (loop == LOOP_CACHING_NOWAIT) {
7466                         /*
7467                          * We want to skip the LOOP_CACHING_WAIT step if we
7468                          * don't have any unached bgs and we've alrelady done a
7469                          * full search through.
7470                          */
7471                         if (orig_have_caching_bg || !full_search)
7472                                 loop = LOOP_CACHING_WAIT;
7473                         else
7474                                 loop = LOOP_ALLOC_CHUNK;
7475                 } else {
7476                         loop++;
7477                 }
7478
7479                 if (loop == LOOP_ALLOC_CHUNK) {
7480                         struct btrfs_trans_handle *trans;
7481                         int exist = 0;
7482
7483                         trans = current->journal_info;
7484                         if (trans)
7485                                 exist = 1;
7486                         else
7487                                 trans = btrfs_join_transaction(root);
7488
7489                         if (IS_ERR(trans)) {
7490                                 ret = PTR_ERR(trans);
7491                                 goto out;
7492                         }
7493
7494                         ret = do_chunk_alloc(trans, root, flags,
7495                                              CHUNK_ALLOC_FORCE);
7496
7497                         /*
7498                          * If we can't allocate a new chunk we've already looped
7499                          * through at least once, move on to the NO_EMPTY_SIZE
7500                          * case.
7501                          */
7502                         if (ret == -ENOSPC)
7503                                 loop = LOOP_NO_EMPTY_SIZE;
7504
7505                         /*
7506                          * Do not bail out on ENOSPC since we
7507                          * can do more things.
7508                          */
7509                         if (ret < 0 && ret != -ENOSPC)
7510                                 btrfs_abort_transaction(trans,
7511                                                         root, ret);
7512                         else
7513                                 ret = 0;
7514                         if (!exist)
7515                                 btrfs_end_transaction(trans, root);
7516                         if (ret)
7517                                 goto out;
7518                 }
7519
7520                 if (loop == LOOP_NO_EMPTY_SIZE) {
7521                         /*
7522                          * Don't loop again if we already have no empty_size and
7523                          * no empty_cluster.
7524                          */
7525                         if (empty_size == 0 &&
7526                             empty_cluster == 0) {
7527                                 ret = -ENOSPC;
7528                                 goto out;
7529                         }
7530                         empty_size = 0;
7531                         empty_cluster = 0;
7532                 }
7533
7534                 goto search;
7535         } else if (!ins->objectid) {
7536                 ret = -ENOSPC;
7537         } else if (ins->objectid) {
7538                 if (!use_cluster && last_ptr) {
7539                         spin_lock(&last_ptr->lock);
7540                         last_ptr->window_start = ins->objectid;
7541                         spin_unlock(&last_ptr->lock);
7542                 }
7543                 ret = 0;
7544         }
7545 out:
7546         if (ret == -ENOSPC) {
7547                 spin_lock(&space_info->lock);
7548                 space_info->max_extent_size = max_extent_size;
7549                 spin_unlock(&space_info->lock);
7550                 ins->offset = max_extent_size;
7551         }
7552         return ret;
7553 }
7554
7555 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
7556                             int dump_block_groups)
7557 {
7558         struct btrfs_block_group_cache *cache;
7559         int index = 0;
7560
7561         spin_lock(&info->lock);
7562         printk(KERN_INFO "BTRFS: space_info %llu has %llu free, is %sfull\n",
7563                info->flags,
7564                info->total_bytes - info->bytes_used - info->bytes_pinned -
7565                info->bytes_reserved - info->bytes_readonly,
7566                (info->full) ? "" : "not ");
7567         printk(KERN_INFO "BTRFS: space_info total=%llu, used=%llu, pinned=%llu, "
7568                "reserved=%llu, may_use=%llu, readonly=%llu\n",
7569                info->total_bytes, info->bytes_used, info->bytes_pinned,
7570                info->bytes_reserved, info->bytes_may_use,
7571                info->bytes_readonly);
7572         spin_unlock(&info->lock);
7573
7574         if (!dump_block_groups)
7575                 return;
7576
7577         down_read(&info->groups_sem);
7578 again:
7579         list_for_each_entry(cache, &info->block_groups[index], list) {
7580                 spin_lock(&cache->lock);
7581                 printk(KERN_INFO "BTRFS: "
7582                            "block group %llu has %llu bytes, "
7583                            "%llu used %llu pinned %llu reserved %s\n",
7584                        cache->key.objectid, cache->key.offset,
7585                        btrfs_block_group_used(&cache->item), cache->pinned,
7586                        cache->reserved, cache->ro ? "[readonly]" : "");
7587                 btrfs_dump_free_space(cache, bytes);
7588                 spin_unlock(&cache->lock);
7589         }
7590         if (++index < BTRFS_NR_RAID_TYPES)
7591                 goto again;
7592         up_read(&info->groups_sem);
7593 }
7594
7595 int btrfs_reserve_extent(struct btrfs_root *root,
7596                          u64 num_bytes, u64 min_alloc_size,
7597                          u64 empty_size, u64 hint_byte,
7598                          struct btrfs_key *ins, int is_data, int delalloc)
7599 {
7600         bool final_tried = num_bytes == min_alloc_size;
7601         u64 flags;
7602         int ret;
7603
7604         flags = btrfs_get_alloc_profile(root, is_data);
7605 again:
7606         WARN_ON(num_bytes < root->sectorsize);
7607         ret = find_free_extent(root, num_bytes, empty_size, hint_byte, ins,
7608                                flags, delalloc);
7609
7610         if (ret == -ENOSPC) {
7611                 if (!final_tried && ins->offset) {
7612                         num_bytes = min(num_bytes >> 1, ins->offset);
7613                         num_bytes = round_down(num_bytes, root->sectorsize);
7614                         num_bytes = max(num_bytes, min_alloc_size);
7615                         if (num_bytes == min_alloc_size)
7616                                 final_tried = true;
7617                         goto again;
7618                 } else if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
7619                         struct btrfs_space_info *sinfo;
7620
7621                         sinfo = __find_space_info(root->fs_info, flags);
7622                         btrfs_err(root->fs_info, "allocation failed flags %llu, wanted %llu",
7623                                 flags, num_bytes);
7624                         if (sinfo)
7625                                 dump_space_info(sinfo, num_bytes, 1);
7626                 }
7627         }
7628
7629         return ret;
7630 }
7631
7632 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
7633                                         u64 start, u64 len,
7634                                         int pin, int delalloc)
7635 {
7636         struct btrfs_block_group_cache *cache;
7637         int ret = 0;
7638
7639         cache = btrfs_lookup_block_group(root->fs_info, start);
7640         if (!cache) {
7641                 btrfs_err(root->fs_info, "Unable to find block group for %llu",
7642                         start);
7643                 return -ENOSPC;
7644         }
7645
7646         if (pin)
7647                 pin_down_extent(root, cache, start, len, 1);
7648         else {
7649                 if (btrfs_test_opt(root, DISCARD))
7650                         ret = btrfs_discard_extent(root, start, len, NULL);
7651                 btrfs_add_free_space(cache, start, len);
7652                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE, delalloc);
7653         }
7654
7655         btrfs_put_block_group(cache);
7656
7657         trace_btrfs_reserved_extent_free(root, start, len);
7658
7659         return ret;
7660 }
7661
7662 int btrfs_free_reserved_extent(struct btrfs_root *root,
7663                                u64 start, u64 len, int delalloc)
7664 {
7665         return __btrfs_free_reserved_extent(root, start, len, 0, delalloc);
7666 }
7667
7668 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
7669                                        u64 start, u64 len)
7670 {
7671         return __btrfs_free_reserved_extent(root, start, len, 1, 0);
7672 }
7673
7674 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
7675                                       struct btrfs_root *root,
7676                                       u64 parent, u64 root_objectid,
7677                                       u64 flags, u64 owner, u64 offset,
7678                                       struct btrfs_key *ins, int ref_mod)
7679 {
7680         int ret;
7681         struct btrfs_fs_info *fs_info = root->fs_info;
7682         struct btrfs_extent_item *extent_item;
7683         struct btrfs_extent_inline_ref *iref;
7684         struct btrfs_path *path;
7685         struct extent_buffer *leaf;
7686         int type;
7687         u32 size;
7688
7689         if (parent > 0)
7690                 type = BTRFS_SHARED_DATA_REF_KEY;
7691         else
7692                 type = BTRFS_EXTENT_DATA_REF_KEY;
7693
7694         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
7695
7696         path = btrfs_alloc_path();
7697         if (!path)
7698                 return -ENOMEM;
7699
7700         path->leave_spinning = 1;
7701         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
7702                                       ins, size);
7703         if (ret) {
7704                 btrfs_free_path(path);
7705                 return ret;
7706         }
7707
7708         leaf = path->nodes[0];
7709         extent_item = btrfs_item_ptr(leaf, path->slots[0],
7710                                      struct btrfs_extent_item);
7711         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
7712         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
7713         btrfs_set_extent_flags(leaf, extent_item,
7714                                flags | BTRFS_EXTENT_FLAG_DATA);
7715
7716         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
7717         btrfs_set_extent_inline_ref_type(leaf, iref, type);
7718         if (parent > 0) {
7719                 struct btrfs_shared_data_ref *ref;
7720                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
7721                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
7722                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
7723         } else {
7724                 struct btrfs_extent_data_ref *ref;
7725                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
7726                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
7727                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
7728                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
7729                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
7730         }
7731
7732         btrfs_mark_buffer_dirty(path->nodes[0]);
7733         btrfs_free_path(path);
7734
7735         ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
7736                                           ins->offset);
7737         if (ret)
7738                 return ret;
7739
7740         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
7741         if (ret) { /* -ENOENT, logic error */
7742                 btrfs_err(fs_info, "update block group failed for %llu %llu",
7743                         ins->objectid, ins->offset);
7744                 BUG();
7745         }
7746         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
7747         return ret;
7748 }
7749
7750 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
7751                                      struct btrfs_root *root,
7752                                      u64 parent, u64 root_objectid,
7753                                      u64 flags, struct btrfs_disk_key *key,
7754                                      int level, struct btrfs_key *ins)
7755 {
7756         int ret;
7757         struct btrfs_fs_info *fs_info = root->fs_info;
7758         struct btrfs_extent_item *extent_item;
7759         struct btrfs_tree_block_info *block_info;
7760         struct btrfs_extent_inline_ref *iref;
7761         struct btrfs_path *path;
7762         struct extent_buffer *leaf;
7763         u32 size = sizeof(*extent_item) + sizeof(*iref);
7764         u64 num_bytes = ins->offset;
7765         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
7766                                                  SKINNY_METADATA);
7767
7768         if (!skinny_metadata)
7769                 size += sizeof(*block_info);
7770
7771         path = btrfs_alloc_path();
7772         if (!path) {
7773                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
7774                                                    root->nodesize);
7775                 return -ENOMEM;
7776         }
7777
7778         path->leave_spinning = 1;
7779         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
7780                                       ins, size);
7781         if (ret) {
7782                 btrfs_free_path(path);
7783                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
7784                                                    root->nodesize);
7785                 return ret;
7786         }
7787
7788         leaf = path->nodes[0];
7789         extent_item = btrfs_item_ptr(leaf, path->slots[0],
7790                                      struct btrfs_extent_item);
7791         btrfs_set_extent_refs(leaf, extent_item, 1);
7792         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
7793         btrfs_set_extent_flags(leaf, extent_item,
7794                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
7795
7796         if (skinny_metadata) {
7797                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
7798                 num_bytes = root->nodesize;
7799         } else {
7800                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
7801                 btrfs_set_tree_block_key(leaf, block_info, key);
7802                 btrfs_set_tree_block_level(leaf, block_info, level);
7803                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
7804         }
7805
7806         if (parent > 0) {
7807                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
7808                 btrfs_set_extent_inline_ref_type(leaf, iref,
7809                                                  BTRFS_SHARED_BLOCK_REF_KEY);
7810                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
7811         } else {
7812                 btrfs_set_extent_inline_ref_type(leaf, iref,
7813                                                  BTRFS_TREE_BLOCK_REF_KEY);
7814                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
7815         }
7816
7817         btrfs_mark_buffer_dirty(leaf);
7818         btrfs_free_path(path);
7819
7820         ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
7821                                           num_bytes);
7822         if (ret)
7823                 return ret;
7824
7825         ret = update_block_group(trans, root, ins->objectid, root->nodesize,
7826                                  1);
7827         if (ret) { /* -ENOENT, logic error */
7828                 btrfs_err(fs_info, "update block group failed for %llu %llu",
7829                         ins->objectid, ins->offset);
7830                 BUG();
7831         }
7832
7833         trace_btrfs_reserved_extent_alloc(root, ins->objectid, root->nodesize);
7834         return ret;
7835 }
7836
7837 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
7838                                      struct btrfs_root *root,
7839                                      u64 root_objectid, u64 owner,
7840                                      u64 offset, u64 ram_bytes,
7841                                      struct btrfs_key *ins)
7842 {
7843         int ret;
7844
7845         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
7846
7847         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
7848                                          ins->offset, 0,
7849                                          root_objectid, owner, offset,
7850                                          ram_bytes, BTRFS_ADD_DELAYED_EXTENT,
7851                                          NULL);
7852         return ret;
7853 }
7854
7855 /*
7856  * this is used by the tree logging recovery code.  It records that
7857  * an extent has been allocated and makes sure to clear the free
7858  * space cache bits as well
7859  */
7860 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
7861                                    struct btrfs_root *root,
7862                                    u64 root_objectid, u64 owner, u64 offset,
7863                                    struct btrfs_key *ins)
7864 {
7865         int ret;
7866         struct btrfs_block_group_cache *block_group;
7867
7868         /*
7869          * Mixed block groups will exclude before processing the log so we only
7870          * need to do the exlude dance if this fs isn't mixed.
7871          */
7872         if (!btrfs_fs_incompat(root->fs_info, MIXED_GROUPS)) {
7873                 ret = __exclude_logged_extent(root, ins->objectid, ins->offset);
7874                 if (ret)
7875                         return ret;
7876         }
7877
7878         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
7879         if (!block_group)
7880                 return -EINVAL;
7881
7882         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
7883                                           RESERVE_ALLOC_NO_ACCOUNT, 0);
7884         BUG_ON(ret); /* logic error */
7885         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
7886                                          0, owner, offset, ins, 1);
7887         btrfs_put_block_group(block_group);
7888         return ret;
7889 }
7890
7891 static struct extent_buffer *
7892 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
7893                       u64 bytenr, int level)
7894 {
7895         struct extent_buffer *buf;
7896
7897         buf = btrfs_find_create_tree_block(root, bytenr);
7898         if (!buf)
7899                 return ERR_PTR(-ENOMEM);
7900         btrfs_set_header_generation(buf, trans->transid);
7901         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
7902         btrfs_tree_lock(buf);
7903         clean_tree_block(trans, root->fs_info, buf);
7904         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
7905
7906         btrfs_set_lock_blocking(buf);
7907         set_extent_buffer_uptodate(buf);
7908
7909         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
7910                 buf->log_index = root->log_transid % 2;
7911                 /*
7912                  * we allow two log transactions at a time, use different
7913                  * EXENT bit to differentiate dirty pages.
7914                  */
7915                 if (buf->log_index == 0)
7916                         set_extent_dirty(&root->dirty_log_pages, buf->start,
7917                                         buf->start + buf->len - 1, GFP_NOFS);
7918                 else
7919                         set_extent_new(&root->dirty_log_pages, buf->start,
7920                                         buf->start + buf->len - 1, GFP_NOFS);
7921         } else {
7922                 buf->log_index = -1;
7923                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
7924                          buf->start + buf->len - 1, GFP_NOFS);
7925         }
7926         trans->blocks_used++;
7927         /* this returns a buffer locked for blocking */
7928         return buf;
7929 }
7930
7931 static struct btrfs_block_rsv *
7932 use_block_rsv(struct btrfs_trans_handle *trans,
7933               struct btrfs_root *root, u32 blocksize)
7934 {
7935         struct btrfs_block_rsv *block_rsv;
7936         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
7937         int ret;
7938         bool global_updated = false;
7939
7940         block_rsv = get_block_rsv(trans, root);
7941
7942         if (unlikely(block_rsv->size == 0))
7943                 goto try_reserve;
7944 again:
7945         ret = block_rsv_use_bytes(block_rsv, blocksize);
7946         if (!ret)
7947                 return block_rsv;
7948
7949         if (block_rsv->failfast)
7950                 return ERR_PTR(ret);
7951
7952         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
7953                 global_updated = true;
7954                 update_global_block_rsv(root->fs_info);
7955                 goto again;
7956         }
7957
7958         if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
7959                 static DEFINE_RATELIMIT_STATE(_rs,
7960                                 DEFAULT_RATELIMIT_INTERVAL * 10,
7961                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
7962                 if (__ratelimit(&_rs))
7963                         WARN(1, KERN_DEBUG
7964                                 "BTRFS: block rsv returned %d\n", ret);
7965         }
7966 try_reserve:
7967         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
7968                                      BTRFS_RESERVE_NO_FLUSH);
7969         if (!ret)
7970                 return block_rsv;
7971         /*
7972          * If we couldn't reserve metadata bytes try and use some from
7973          * the global reserve if its space type is the same as the global
7974          * reservation.
7975          */
7976         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
7977             block_rsv->space_info == global_rsv->space_info) {
7978                 ret = block_rsv_use_bytes(global_rsv, blocksize);
7979                 if (!ret)
7980                         return global_rsv;
7981         }
7982         return ERR_PTR(ret);
7983 }
7984
7985 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
7986                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
7987 {
7988         block_rsv_add_bytes(block_rsv, blocksize, 0);
7989         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
7990 }
7991
7992 /*
7993  * finds a free extent and does all the dirty work required for allocation
7994  * returns the tree buffer or an ERR_PTR on error.
7995  */
7996 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
7997                                         struct btrfs_root *root,
7998                                         u64 parent, u64 root_objectid,
7999                                         struct btrfs_disk_key *key, int level,
8000                                         u64 hint, u64 empty_size)
8001 {
8002         struct btrfs_key ins;
8003         struct btrfs_block_rsv *block_rsv;
8004         struct extent_buffer *buf;
8005         struct btrfs_delayed_extent_op *extent_op;
8006         u64 flags = 0;
8007         int ret;
8008         u32 blocksize = root->nodesize;
8009         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
8010                                                  SKINNY_METADATA);
8011
8012         if (btrfs_test_is_dummy_root(root)) {
8013                 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
8014                                             level);
8015                 if (!IS_ERR(buf))
8016                         root->alloc_bytenr += blocksize;
8017                 return buf;
8018         }
8019
8020         block_rsv = use_block_rsv(trans, root, blocksize);
8021         if (IS_ERR(block_rsv))
8022                 return ERR_CAST(block_rsv);
8023
8024         ret = btrfs_reserve_extent(root, blocksize, blocksize,
8025                                    empty_size, hint, &ins, 0, 0);
8026         if (ret)
8027                 goto out_unuse;
8028
8029         buf = btrfs_init_new_buffer(trans, root, ins.objectid, level);
8030         if (IS_ERR(buf)) {
8031                 ret = PTR_ERR(buf);
8032                 goto out_free_reserved;
8033         }
8034
8035         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
8036                 if (parent == 0)
8037                         parent = ins.objectid;
8038                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
8039         } else
8040                 BUG_ON(parent > 0);
8041
8042         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
8043                 extent_op = btrfs_alloc_delayed_extent_op();
8044                 if (!extent_op) {
8045                         ret = -ENOMEM;
8046                         goto out_free_buf;
8047                 }
8048                 if (key)
8049                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
8050                 else
8051                         memset(&extent_op->key, 0, sizeof(extent_op->key));
8052                 extent_op->flags_to_set = flags;
8053                 extent_op->update_key = skinny_metadata ? false : true;
8054                 extent_op->update_flags = true;
8055                 extent_op->is_data = false;
8056                 extent_op->level = level;
8057
8058                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
8059                                                  ins.objectid, ins.offset,
8060                                                  parent, root_objectid, level,
8061                                                  BTRFS_ADD_DELAYED_EXTENT,
8062                                                  extent_op);
8063                 if (ret)
8064                         goto out_free_delayed;
8065         }
8066         return buf;
8067
8068 out_free_delayed:
8069         btrfs_free_delayed_extent_op(extent_op);
8070 out_free_buf:
8071         free_extent_buffer(buf);
8072 out_free_reserved:
8073         btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 0);
8074 out_unuse:
8075         unuse_block_rsv(root->fs_info, block_rsv, blocksize);
8076         return ERR_PTR(ret);
8077 }
8078
8079 struct walk_control {
8080         u64 refs[BTRFS_MAX_LEVEL];
8081         u64 flags[BTRFS_MAX_LEVEL];
8082         struct btrfs_key update_progress;
8083         int stage;
8084         int level;
8085         int shared_level;
8086         int update_ref;
8087         int keep_locks;
8088         int reada_slot;
8089         int reada_count;
8090         int for_reloc;
8091 };
8092
8093 #define DROP_REFERENCE  1
8094 #define UPDATE_BACKREF  2
8095
8096 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
8097                                      struct btrfs_root *root,
8098                                      struct walk_control *wc,
8099                                      struct btrfs_path *path)
8100 {
8101         u64 bytenr;
8102         u64 generation;
8103         u64 refs;
8104         u64 flags;
8105         u32 nritems;
8106         u32 blocksize;
8107         struct btrfs_key key;
8108         struct extent_buffer *eb;
8109         int ret;
8110         int slot;
8111         int nread = 0;
8112
8113         if (path->slots[wc->level] < wc->reada_slot) {
8114                 wc->reada_count = wc->reada_count * 2 / 3;
8115                 wc->reada_count = max(wc->reada_count, 2);
8116         } else {
8117                 wc->reada_count = wc->reada_count * 3 / 2;
8118                 wc->reada_count = min_t(int, wc->reada_count,
8119                                         BTRFS_NODEPTRS_PER_BLOCK(root));
8120         }
8121
8122         eb = path->nodes[wc->level];
8123         nritems = btrfs_header_nritems(eb);
8124         blocksize = root->nodesize;
8125
8126         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
8127                 if (nread >= wc->reada_count)
8128                         break;
8129
8130                 cond_resched();
8131                 bytenr = btrfs_node_blockptr(eb, slot);
8132                 generation = btrfs_node_ptr_generation(eb, slot);
8133
8134                 if (slot == path->slots[wc->level])
8135                         goto reada;
8136
8137                 if (wc->stage == UPDATE_BACKREF &&
8138                     generation <= root->root_key.offset)
8139                         continue;
8140
8141                 /* We don't lock the tree block, it's OK to be racy here */
8142                 ret = btrfs_lookup_extent_info(trans, root, bytenr,
8143                                                wc->level - 1, 1, &refs,
8144                                                &flags);
8145                 /* We don't care about errors in readahead. */
8146                 if (ret < 0)
8147                         continue;
8148                 BUG_ON(refs == 0);
8149
8150                 if (wc->stage == DROP_REFERENCE) {
8151                         if (refs == 1)
8152                                 goto reada;
8153
8154                         if (wc->level == 1 &&
8155                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8156                                 continue;
8157                         if (!wc->update_ref ||
8158                             generation <= root->root_key.offset)
8159                                 continue;
8160                         btrfs_node_key_to_cpu(eb, &key, slot);
8161                         ret = btrfs_comp_cpu_keys(&key,
8162                                                   &wc->update_progress);
8163                         if (ret < 0)
8164                                 continue;
8165                 } else {
8166                         if (wc->level == 1 &&
8167                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8168                                 continue;
8169                 }
8170 reada:
8171                 readahead_tree_block(root, bytenr);
8172                 nread++;
8173         }
8174         wc->reada_slot = slot;
8175 }
8176
8177 /*
8178  * These may not be seen by the usual inc/dec ref code so we have to
8179  * add them here.
8180  */
8181 static int record_one_subtree_extent(struct btrfs_trans_handle *trans,
8182                                      struct btrfs_root *root, u64 bytenr,
8183                                      u64 num_bytes)
8184 {
8185         struct btrfs_qgroup_extent_record *qrecord;
8186         struct btrfs_delayed_ref_root *delayed_refs;
8187
8188         qrecord = kmalloc(sizeof(*qrecord), GFP_NOFS);
8189         if (!qrecord)
8190                 return -ENOMEM;
8191
8192         qrecord->bytenr = bytenr;
8193         qrecord->num_bytes = num_bytes;
8194         qrecord->old_roots = NULL;
8195
8196         delayed_refs = &trans->transaction->delayed_refs;
8197         spin_lock(&delayed_refs->lock);
8198         if (btrfs_qgroup_insert_dirty_extent(delayed_refs, qrecord))
8199                 kfree(qrecord);
8200         spin_unlock(&delayed_refs->lock);
8201
8202         return 0;
8203 }
8204
8205 static int account_leaf_items(struct btrfs_trans_handle *trans,
8206                               struct btrfs_root *root,
8207                               struct extent_buffer *eb)
8208 {
8209         int nr = btrfs_header_nritems(eb);
8210         int i, extent_type, ret;
8211         struct btrfs_key key;
8212         struct btrfs_file_extent_item *fi;
8213         u64 bytenr, num_bytes;
8214
8215         /* We can be called directly from walk_up_proc() */
8216         if (!root->fs_info->quota_enabled)
8217                 return 0;
8218
8219         for (i = 0; i < nr; i++) {
8220                 btrfs_item_key_to_cpu(eb, &key, i);
8221
8222                 if (key.type != BTRFS_EXTENT_DATA_KEY)
8223                         continue;
8224
8225                 fi = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
8226                 /* filter out non qgroup-accountable extents  */
8227                 extent_type = btrfs_file_extent_type(eb, fi);
8228
8229                 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
8230                         continue;
8231
8232                 bytenr = btrfs_file_extent_disk_bytenr(eb, fi);
8233                 if (!bytenr)
8234                         continue;
8235
8236                 num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
8237
8238                 ret = record_one_subtree_extent(trans, root, bytenr, num_bytes);
8239                 if (ret)
8240                         return ret;
8241         }
8242         return 0;
8243 }
8244
8245 /*
8246  * Walk up the tree from the bottom, freeing leaves and any interior
8247  * nodes which have had all slots visited. If a node (leaf or
8248  * interior) is freed, the node above it will have it's slot
8249  * incremented. The root node will never be freed.
8250  *
8251  * At the end of this function, we should have a path which has all
8252  * slots incremented to the next position for a search. If we need to
8253  * read a new node it will be NULL and the node above it will have the
8254  * correct slot selected for a later read.
8255  *
8256  * If we increment the root nodes slot counter past the number of
8257  * elements, 1 is returned to signal completion of the search.
8258  */
8259 static int adjust_slots_upwards(struct btrfs_root *root,
8260                                 struct btrfs_path *path, int root_level)
8261 {
8262         int level = 0;
8263         int nr, slot;
8264         struct extent_buffer *eb;
8265
8266         if (root_level == 0)
8267                 return 1;
8268
8269         while (level <= root_level) {
8270                 eb = path->nodes[level];
8271                 nr = btrfs_header_nritems(eb);
8272                 path->slots[level]++;
8273                 slot = path->slots[level];
8274                 if (slot >= nr || level == 0) {
8275                         /*
8276                          * Don't free the root -  we will detect this
8277                          * condition after our loop and return a
8278                          * positive value for caller to stop walking the tree.
8279                          */
8280                         if (level != root_level) {
8281                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8282                                 path->locks[level] = 0;
8283
8284                                 free_extent_buffer(eb);
8285                                 path->nodes[level] = NULL;
8286                                 path->slots[level] = 0;
8287                         }
8288                 } else {
8289                         /*
8290                          * We have a valid slot to walk back down
8291                          * from. Stop here so caller can process these
8292                          * new nodes.
8293                          */
8294                         break;
8295                 }
8296
8297                 level++;
8298         }
8299
8300         eb = path->nodes[root_level];
8301         if (path->slots[root_level] >= btrfs_header_nritems(eb))
8302                 return 1;
8303
8304         return 0;
8305 }
8306
8307 /*
8308  * root_eb is the subtree root and is locked before this function is called.
8309  */
8310 static int account_shared_subtree(struct btrfs_trans_handle *trans,
8311                                   struct btrfs_root *root,
8312                                   struct extent_buffer *root_eb,
8313                                   u64 root_gen,
8314                                   int root_level)
8315 {
8316         int ret = 0;
8317         int level;
8318         struct extent_buffer *eb = root_eb;
8319         struct btrfs_path *path = NULL;
8320
8321         BUG_ON(root_level < 0 || root_level > BTRFS_MAX_LEVEL);
8322         BUG_ON(root_eb == NULL);
8323
8324         if (!root->fs_info->quota_enabled)
8325                 return 0;
8326
8327         if (!extent_buffer_uptodate(root_eb)) {
8328                 ret = btrfs_read_buffer(root_eb, root_gen);
8329                 if (ret)
8330                         goto out;
8331         }
8332
8333         if (root_level == 0) {
8334                 ret = account_leaf_items(trans, root, root_eb);
8335                 goto out;
8336         }
8337
8338         path = btrfs_alloc_path();
8339         if (!path)
8340                 return -ENOMEM;
8341
8342         /*
8343          * Walk down the tree.  Missing extent blocks are filled in as
8344          * we go. Metadata is accounted every time we read a new
8345          * extent block.
8346          *
8347          * When we reach a leaf, we account for file extent items in it,
8348          * walk back up the tree (adjusting slot pointers as we go)
8349          * and restart the search process.
8350          */
8351         extent_buffer_get(root_eb); /* For path */
8352         path->nodes[root_level] = root_eb;
8353         path->slots[root_level] = 0;
8354         path->locks[root_level] = 0; /* so release_path doesn't try to unlock */
8355 walk_down:
8356         level = root_level;
8357         while (level >= 0) {
8358                 if (path->nodes[level] == NULL) {
8359                         int parent_slot;
8360                         u64 child_gen;
8361                         u64 child_bytenr;
8362
8363                         /* We need to get child blockptr/gen from
8364                          * parent before we can read it. */
8365                         eb = path->nodes[level + 1];
8366                         parent_slot = path->slots[level + 1];
8367                         child_bytenr = btrfs_node_blockptr(eb, parent_slot);
8368                         child_gen = btrfs_node_ptr_generation(eb, parent_slot);
8369
8370                         eb = read_tree_block(root, child_bytenr, child_gen);
8371                         if (IS_ERR(eb)) {
8372                                 ret = PTR_ERR(eb);
8373                                 goto out;
8374                         } else if (!extent_buffer_uptodate(eb)) {
8375                                 free_extent_buffer(eb);
8376                                 ret = -EIO;
8377                                 goto out;
8378                         }
8379
8380                         path->nodes[level] = eb;
8381                         path->slots[level] = 0;
8382
8383                         btrfs_tree_read_lock(eb);
8384                         btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
8385                         path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
8386
8387                         ret = record_one_subtree_extent(trans, root, child_bytenr,
8388                                                         root->nodesize);
8389                         if (ret)
8390                                 goto out;
8391                 }
8392
8393                 if (level == 0) {
8394                         ret = account_leaf_items(trans, root, path->nodes[level]);
8395                         if (ret)
8396                                 goto out;
8397
8398                         /* Nonzero return here means we completed our search */
8399                         ret = adjust_slots_upwards(root, path, root_level);
8400                         if (ret)
8401                                 break;
8402
8403                         /* Restart search with new slots */
8404                         goto walk_down;
8405                 }
8406
8407                 level--;
8408         }
8409
8410         ret = 0;
8411 out:
8412         btrfs_free_path(path);
8413
8414         return ret;
8415 }
8416
8417 /*
8418  * helper to process tree block while walking down the tree.
8419  *
8420  * when wc->stage == UPDATE_BACKREF, this function updates
8421  * back refs for pointers in the block.
8422  *
8423  * NOTE: return value 1 means we should stop walking down.
8424  */
8425 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
8426                                    struct btrfs_root *root,
8427                                    struct btrfs_path *path,
8428                                    struct walk_control *wc, int lookup_info)
8429 {
8430         int level = wc->level;
8431         struct extent_buffer *eb = path->nodes[level];
8432         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8433         int ret;
8434
8435         if (wc->stage == UPDATE_BACKREF &&
8436             btrfs_header_owner(eb) != root->root_key.objectid)
8437                 return 1;
8438
8439         /*
8440          * when reference count of tree block is 1, it won't increase
8441          * again. once full backref flag is set, we never clear it.
8442          */
8443         if (lookup_info &&
8444             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
8445              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
8446                 BUG_ON(!path->locks[level]);
8447                 ret = btrfs_lookup_extent_info(trans, root,
8448                                                eb->start, level, 1,
8449                                                &wc->refs[level],
8450                                                &wc->flags[level]);
8451                 BUG_ON(ret == -ENOMEM);
8452                 if (ret)
8453                         return ret;
8454                 BUG_ON(wc->refs[level] == 0);
8455         }
8456
8457         if (wc->stage == DROP_REFERENCE) {
8458                 if (wc->refs[level] > 1)
8459                         return 1;
8460
8461                 if (path->locks[level] && !wc->keep_locks) {
8462                         btrfs_tree_unlock_rw(eb, path->locks[level]);
8463                         path->locks[level] = 0;
8464                 }
8465                 return 0;
8466         }
8467
8468         /* wc->stage == UPDATE_BACKREF */
8469         if (!(wc->flags[level] & flag)) {
8470                 BUG_ON(!path->locks[level]);
8471                 ret = btrfs_inc_ref(trans, root, eb, 1);
8472                 BUG_ON(ret); /* -ENOMEM */
8473                 ret = btrfs_dec_ref(trans, root, eb, 0);
8474                 BUG_ON(ret); /* -ENOMEM */
8475                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
8476                                                   eb->len, flag,
8477                                                   btrfs_header_level(eb), 0);
8478                 BUG_ON(ret); /* -ENOMEM */
8479                 wc->flags[level] |= flag;
8480         }
8481
8482         /*
8483          * the block is shared by multiple trees, so it's not good to
8484          * keep the tree lock
8485          */
8486         if (path->locks[level] && level > 0) {
8487                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8488                 path->locks[level] = 0;
8489         }
8490         return 0;
8491 }
8492
8493 /*
8494  * helper to process tree block pointer.
8495  *
8496  * when wc->stage == DROP_REFERENCE, this function checks
8497  * reference count of the block pointed to. if the block
8498  * is shared and we need update back refs for the subtree
8499  * rooted at the block, this function changes wc->stage to
8500  * UPDATE_BACKREF. if the block is shared and there is no
8501  * need to update back, this function drops the reference
8502  * to the block.
8503  *
8504  * NOTE: return value 1 means we should stop walking down.
8505  */
8506 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
8507                                  struct btrfs_root *root,
8508                                  struct btrfs_path *path,
8509                                  struct walk_control *wc, int *lookup_info)
8510 {
8511         u64 bytenr;
8512         u64 generation;
8513         u64 parent;
8514         u32 blocksize;
8515         struct btrfs_key key;
8516         struct extent_buffer *next;
8517         int level = wc->level;
8518         int reada = 0;
8519         int ret = 0;
8520         bool need_account = false;
8521
8522         generation = btrfs_node_ptr_generation(path->nodes[level],
8523                                                path->slots[level]);
8524         /*
8525          * if the lower level block was created before the snapshot
8526          * was created, we know there is no need to update back refs
8527          * for the subtree
8528          */
8529         if (wc->stage == UPDATE_BACKREF &&
8530             generation <= root->root_key.offset) {
8531                 *lookup_info = 1;
8532                 return 1;
8533         }
8534
8535         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
8536         blocksize = root->nodesize;
8537
8538         next = btrfs_find_tree_block(root->fs_info, bytenr);
8539         if (!next) {
8540                 next = btrfs_find_create_tree_block(root, bytenr);
8541                 if (!next)
8542                         return -ENOMEM;
8543                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
8544                                                level - 1);
8545                 reada = 1;
8546         }
8547         btrfs_tree_lock(next);
8548         btrfs_set_lock_blocking(next);
8549
8550         ret = btrfs_lookup_extent_info(trans, root, bytenr, level - 1, 1,
8551                                        &wc->refs[level - 1],
8552                                        &wc->flags[level - 1]);
8553         if (ret < 0) {
8554                 btrfs_tree_unlock(next);
8555                 return ret;
8556         }
8557
8558         if (unlikely(wc->refs[level - 1] == 0)) {
8559                 btrfs_err(root->fs_info, "Missing references.");
8560                 BUG();
8561         }
8562         *lookup_info = 0;
8563
8564         if (wc->stage == DROP_REFERENCE) {
8565                 if (wc->refs[level - 1] > 1) {
8566                         need_account = true;
8567                         if (level == 1 &&
8568                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8569                                 goto skip;
8570
8571                         if (!wc->update_ref ||
8572                             generation <= root->root_key.offset)
8573                                 goto skip;
8574
8575                         btrfs_node_key_to_cpu(path->nodes[level], &key,
8576                                               path->slots[level]);
8577                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
8578                         if (ret < 0)
8579                                 goto skip;
8580
8581                         wc->stage = UPDATE_BACKREF;
8582                         wc->shared_level = level - 1;
8583                 }
8584         } else {
8585                 if (level == 1 &&
8586                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8587                         goto skip;
8588         }
8589
8590         if (!btrfs_buffer_uptodate(next, generation, 0)) {
8591                 btrfs_tree_unlock(next);
8592                 free_extent_buffer(next);
8593                 next = NULL;
8594                 *lookup_info = 1;
8595         }
8596
8597         if (!next) {
8598                 if (reada && level == 1)
8599                         reada_walk_down(trans, root, wc, path);
8600                 next = read_tree_block(root, bytenr, generation);
8601                 if (IS_ERR(next)) {
8602                         return PTR_ERR(next);
8603                 } else if (!extent_buffer_uptodate(next)) {
8604                         free_extent_buffer(next);
8605                         return -EIO;
8606                 }
8607                 btrfs_tree_lock(next);
8608                 btrfs_set_lock_blocking(next);
8609         }
8610
8611         level--;
8612         BUG_ON(level != btrfs_header_level(next));
8613         path->nodes[level] = next;
8614         path->slots[level] = 0;
8615         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8616         wc->level = level;
8617         if (wc->level == 1)
8618                 wc->reada_slot = 0;
8619         return 0;
8620 skip:
8621         wc->refs[level - 1] = 0;
8622         wc->flags[level - 1] = 0;
8623         if (wc->stage == DROP_REFERENCE) {
8624                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
8625                         parent = path->nodes[level]->start;
8626                 } else {
8627                         BUG_ON(root->root_key.objectid !=
8628                                btrfs_header_owner(path->nodes[level]));
8629                         parent = 0;
8630                 }
8631
8632                 if (need_account) {
8633                         ret = account_shared_subtree(trans, root, next,
8634                                                      generation, level - 1);
8635                         if (ret) {
8636                                 btrfs_err_rl(root->fs_info,
8637                                         "Error "
8638                                         "%d accounting shared subtree. Quota "
8639                                         "is out of sync, rescan required.",
8640                                         ret);
8641                         }
8642                 }
8643                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
8644                                 root->root_key.objectid, level - 1, 0);
8645                 BUG_ON(ret); /* -ENOMEM */
8646         }
8647         btrfs_tree_unlock(next);
8648         free_extent_buffer(next);
8649         *lookup_info = 1;
8650         return 1;
8651 }
8652
8653 /*
8654  * helper to process tree block while walking up the tree.
8655  *
8656  * when wc->stage == DROP_REFERENCE, this function drops
8657  * reference count on the block.
8658  *
8659  * when wc->stage == UPDATE_BACKREF, this function changes
8660  * wc->stage back to DROP_REFERENCE if we changed wc->stage
8661  * to UPDATE_BACKREF previously while processing the block.
8662  *
8663  * NOTE: return value 1 means we should stop walking up.
8664  */
8665 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
8666                                  struct btrfs_root *root,
8667                                  struct btrfs_path *path,
8668                                  struct walk_control *wc)
8669 {
8670         int ret;
8671         int level = wc->level;
8672         struct extent_buffer *eb = path->nodes[level];
8673         u64 parent = 0;
8674
8675         if (wc->stage == UPDATE_BACKREF) {
8676                 BUG_ON(wc->shared_level < level);
8677                 if (level < wc->shared_level)
8678                         goto out;
8679
8680                 ret = find_next_key(path, level + 1, &wc->update_progress);
8681                 if (ret > 0)
8682                         wc->update_ref = 0;
8683
8684                 wc->stage = DROP_REFERENCE;
8685                 wc->shared_level = -1;
8686                 path->slots[level] = 0;
8687
8688                 /*
8689                  * check reference count again if the block isn't locked.
8690                  * we should start walking down the tree again if reference
8691                  * count is one.
8692                  */
8693                 if (!path->locks[level]) {
8694                         BUG_ON(level == 0);
8695                         btrfs_tree_lock(eb);
8696                         btrfs_set_lock_blocking(eb);
8697                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8698
8699                         ret = btrfs_lookup_extent_info(trans, root,
8700                                                        eb->start, level, 1,
8701                                                        &wc->refs[level],
8702                                                        &wc->flags[level]);
8703                         if (ret < 0) {
8704                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8705                                 path->locks[level] = 0;
8706                                 return ret;
8707                         }
8708                         BUG_ON(wc->refs[level] == 0);
8709                         if (wc->refs[level] == 1) {
8710                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8711                                 path->locks[level] = 0;
8712                                 return 1;
8713                         }
8714                 }
8715         }
8716
8717         /* wc->stage == DROP_REFERENCE */
8718         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
8719
8720         if (wc->refs[level] == 1) {
8721                 if (level == 0) {
8722                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8723                                 ret = btrfs_dec_ref(trans, root, eb, 1);
8724                         else
8725                                 ret = btrfs_dec_ref(trans, root, eb, 0);
8726                         BUG_ON(ret); /* -ENOMEM */
8727                         ret = account_leaf_items(trans, root, eb);
8728                         if (ret) {
8729                                 btrfs_err_rl(root->fs_info,
8730                                         "error "
8731                                         "%d accounting leaf items. Quota "
8732                                         "is out of sync, rescan required.",
8733                                         ret);
8734                         }
8735                 }
8736                 /* make block locked assertion in clean_tree_block happy */
8737                 if (!path->locks[level] &&
8738                     btrfs_header_generation(eb) == trans->transid) {
8739                         btrfs_tree_lock(eb);
8740                         btrfs_set_lock_blocking(eb);
8741                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8742                 }
8743                 clean_tree_block(trans, root->fs_info, eb);
8744         }
8745
8746         if (eb == root->node) {
8747                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8748                         parent = eb->start;
8749                 else
8750                         BUG_ON(root->root_key.objectid !=
8751                                btrfs_header_owner(eb));
8752         } else {
8753                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8754                         parent = path->nodes[level + 1]->start;
8755                 else
8756                         BUG_ON(root->root_key.objectid !=
8757                                btrfs_header_owner(path->nodes[level + 1]));
8758         }
8759
8760         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
8761 out:
8762         wc->refs[level] = 0;
8763         wc->flags[level] = 0;
8764         return 0;
8765 }
8766
8767 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
8768                                    struct btrfs_root *root,
8769                                    struct btrfs_path *path,
8770                                    struct walk_control *wc)
8771 {
8772         int level = wc->level;
8773         int lookup_info = 1;
8774         int ret;
8775
8776         while (level >= 0) {
8777                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
8778                 if (ret > 0)
8779                         break;
8780
8781                 if (level == 0)
8782                         break;
8783
8784                 if (path->slots[level] >=
8785                     btrfs_header_nritems(path->nodes[level]))
8786                         break;
8787
8788                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
8789                 if (ret > 0) {
8790                         path->slots[level]++;
8791                         continue;
8792                 } else if (ret < 0)
8793                         return ret;
8794                 level = wc->level;
8795         }
8796         return 0;
8797 }
8798
8799 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
8800                                  struct btrfs_root *root,
8801                                  struct btrfs_path *path,
8802                                  struct walk_control *wc, int max_level)
8803 {
8804         int level = wc->level;
8805         int ret;
8806
8807         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
8808         while (level < max_level && path->nodes[level]) {
8809                 wc->level = level;
8810                 if (path->slots[level] + 1 <
8811                     btrfs_header_nritems(path->nodes[level])) {
8812                         path->slots[level]++;
8813                         return 0;
8814                 } else {
8815                         ret = walk_up_proc(trans, root, path, wc);
8816                         if (ret > 0)
8817                                 return 0;
8818
8819                         if (path->locks[level]) {
8820                                 btrfs_tree_unlock_rw(path->nodes[level],
8821                                                      path->locks[level]);
8822                                 path->locks[level] = 0;
8823                         }
8824                         free_extent_buffer(path->nodes[level]);
8825                         path->nodes[level] = NULL;
8826                         level++;
8827                 }
8828         }
8829         return 1;
8830 }
8831
8832 /*
8833  * drop a subvolume tree.
8834  *
8835  * this function traverses the tree freeing any blocks that only
8836  * referenced by the tree.
8837  *
8838  * when a shared tree block is found. this function decreases its
8839  * reference count by one. if update_ref is true, this function
8840  * also make sure backrefs for the shared block and all lower level
8841  * blocks are properly updated.
8842  *
8843  * If called with for_reloc == 0, may exit early with -EAGAIN
8844  */
8845 int btrfs_drop_snapshot(struct btrfs_root *root,
8846                          struct btrfs_block_rsv *block_rsv, int update_ref,
8847                          int for_reloc)
8848 {
8849         struct btrfs_path *path;
8850         struct btrfs_trans_handle *trans;
8851         struct btrfs_root *tree_root = root->fs_info->tree_root;
8852         struct btrfs_root_item *root_item = &root->root_item;
8853         struct walk_control *wc;
8854         struct btrfs_key key;
8855         int err = 0;
8856         int ret;
8857         int level;
8858         bool root_dropped = false;
8859
8860         btrfs_debug(root->fs_info, "Drop subvolume %llu", root->objectid);
8861
8862         path = btrfs_alloc_path();
8863         if (!path) {
8864                 err = -ENOMEM;
8865                 goto out;
8866         }
8867
8868         wc = kzalloc(sizeof(*wc), GFP_NOFS);
8869         if (!wc) {
8870                 btrfs_free_path(path);
8871                 err = -ENOMEM;
8872                 goto out;
8873         }
8874
8875         trans = btrfs_start_transaction(tree_root, 0);
8876         if (IS_ERR(trans)) {
8877                 err = PTR_ERR(trans);
8878                 goto out_free;
8879         }
8880
8881         if (block_rsv)
8882                 trans->block_rsv = block_rsv;
8883
8884         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
8885                 level = btrfs_header_level(root->node);
8886                 path->nodes[level] = btrfs_lock_root_node(root);
8887                 btrfs_set_lock_blocking(path->nodes[level]);
8888                 path->slots[level] = 0;
8889                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8890                 memset(&wc->update_progress, 0,
8891                        sizeof(wc->update_progress));
8892         } else {
8893                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
8894                 memcpy(&wc->update_progress, &key,
8895                        sizeof(wc->update_progress));
8896
8897                 level = root_item->drop_level;
8898                 BUG_ON(level == 0);
8899                 path->lowest_level = level;
8900                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
8901                 path->lowest_level = 0;
8902                 if (ret < 0) {
8903                         err = ret;
8904                         goto out_end_trans;
8905                 }
8906                 WARN_ON(ret > 0);
8907
8908                 /*
8909                  * unlock our path, this is safe because only this
8910                  * function is allowed to delete this snapshot
8911                  */
8912                 btrfs_unlock_up_safe(path, 0);
8913
8914                 level = btrfs_header_level(root->node);
8915                 while (1) {
8916                         btrfs_tree_lock(path->nodes[level]);
8917                         btrfs_set_lock_blocking(path->nodes[level]);
8918                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8919
8920                         ret = btrfs_lookup_extent_info(trans, root,
8921                                                 path->nodes[level]->start,
8922                                                 level, 1, &wc->refs[level],
8923                                                 &wc->flags[level]);
8924                         if (ret < 0) {
8925                                 err = ret;
8926                                 goto out_end_trans;
8927                         }
8928                         BUG_ON(wc->refs[level] == 0);
8929
8930                         if (level == root_item->drop_level)
8931                                 break;
8932
8933                         btrfs_tree_unlock(path->nodes[level]);
8934                         path->locks[level] = 0;
8935                         WARN_ON(wc->refs[level] != 1);
8936                         level--;
8937                 }
8938         }
8939
8940         wc->level = level;
8941         wc->shared_level = -1;
8942         wc->stage = DROP_REFERENCE;
8943         wc->update_ref = update_ref;
8944         wc->keep_locks = 0;
8945         wc->for_reloc = for_reloc;
8946         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
8947
8948         while (1) {
8949
8950                 ret = walk_down_tree(trans, root, path, wc);
8951                 if (ret < 0) {
8952                         err = ret;
8953                         break;
8954                 }
8955
8956                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
8957                 if (ret < 0) {
8958                         err = ret;
8959                         break;
8960                 }
8961
8962                 if (ret > 0) {
8963                         BUG_ON(wc->stage != DROP_REFERENCE);
8964                         break;
8965                 }
8966
8967                 if (wc->stage == DROP_REFERENCE) {
8968                         level = wc->level;
8969                         btrfs_node_key(path->nodes[level],
8970                                        &root_item->drop_progress,
8971                                        path->slots[level]);
8972                         root_item->drop_level = level;
8973                 }
8974
8975                 BUG_ON(wc->level == 0);
8976                 if (btrfs_should_end_transaction(trans, tree_root) ||
8977                     (!for_reloc && btrfs_need_cleaner_sleep(root))) {
8978                         ret = btrfs_update_root(trans, tree_root,
8979                                                 &root->root_key,
8980                                                 root_item);
8981                         if (ret) {
8982                                 btrfs_abort_transaction(trans, tree_root, ret);
8983                                 err = ret;
8984                                 goto out_end_trans;
8985                         }
8986
8987                         btrfs_end_transaction_throttle(trans, tree_root);
8988                         if (!for_reloc && btrfs_need_cleaner_sleep(root)) {
8989                                 pr_debug("BTRFS: drop snapshot early exit\n");
8990                                 err = -EAGAIN;
8991                                 goto out_free;
8992                         }
8993
8994                         trans = btrfs_start_transaction(tree_root, 0);
8995                         if (IS_ERR(trans)) {
8996                                 err = PTR_ERR(trans);
8997                                 goto out_free;
8998                         }
8999                         if (block_rsv)
9000                                 trans->block_rsv = block_rsv;
9001                 }
9002         }
9003         btrfs_release_path(path);
9004         if (err)
9005                 goto out_end_trans;
9006
9007         ret = btrfs_del_root(trans, tree_root, &root->root_key);
9008         if (ret) {
9009                 btrfs_abort_transaction(trans, tree_root, ret);
9010                 goto out_end_trans;
9011         }
9012
9013         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
9014                 ret = btrfs_find_root(tree_root, &root->root_key, path,
9015                                       NULL, NULL);
9016                 if (ret < 0) {
9017                         btrfs_abort_transaction(trans, tree_root, ret);
9018                         err = ret;
9019                         goto out_end_trans;
9020                 } else if (ret > 0) {
9021                         /* if we fail to delete the orphan item this time
9022                          * around, it'll get picked up the next time.
9023                          *
9024                          * The most common failure here is just -ENOENT.
9025                          */
9026                         btrfs_del_orphan_item(trans, tree_root,
9027                                               root->root_key.objectid);
9028                 }
9029         }
9030
9031         if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
9032                 btrfs_add_dropped_root(trans, root);
9033         } else {
9034                 free_extent_buffer(root->node);
9035                 free_extent_buffer(root->commit_root);
9036                 btrfs_put_fs_root(root);
9037         }
9038         root_dropped = true;
9039 out_end_trans:
9040         btrfs_end_transaction_throttle(trans, tree_root);
9041 out_free:
9042         kfree(wc);
9043         btrfs_free_path(path);
9044 out:
9045         /*
9046          * So if we need to stop dropping the snapshot for whatever reason we
9047          * need to make sure to add it back to the dead root list so that we
9048          * keep trying to do the work later.  This also cleans up roots if we
9049          * don't have it in the radix (like when we recover after a power fail
9050          * or unmount) so we don't leak memory.
9051          */
9052         if (!for_reloc && root_dropped == false)
9053                 btrfs_add_dead_root(root);
9054         if (err && err != -EAGAIN)
9055                 btrfs_std_error(root->fs_info, err, NULL);
9056         return err;
9057 }
9058
9059 /*
9060  * drop subtree rooted at tree block 'node'.
9061  *
9062  * NOTE: this function will unlock and release tree block 'node'
9063  * only used by relocation code
9064  */
9065 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
9066                         struct btrfs_root *root,
9067                         struct extent_buffer *node,
9068                         struct extent_buffer *parent)
9069 {
9070         struct btrfs_path *path;
9071         struct walk_control *wc;
9072         int level;
9073         int parent_level;
9074         int ret = 0;
9075         int wret;
9076
9077         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
9078
9079         path = btrfs_alloc_path();
9080         if (!path)
9081                 return -ENOMEM;
9082
9083         wc = kzalloc(sizeof(*wc), GFP_NOFS);
9084         if (!wc) {
9085                 btrfs_free_path(path);
9086                 return -ENOMEM;
9087         }
9088
9089         btrfs_assert_tree_locked(parent);
9090         parent_level = btrfs_header_level(parent);
9091         extent_buffer_get(parent);
9092         path->nodes[parent_level] = parent;
9093         path->slots[parent_level] = btrfs_header_nritems(parent);
9094
9095         btrfs_assert_tree_locked(node);
9096         level = btrfs_header_level(node);
9097         path->nodes[level] = node;
9098         path->slots[level] = 0;
9099         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9100
9101         wc->refs[parent_level] = 1;
9102         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
9103         wc->level = level;
9104         wc->shared_level = -1;
9105         wc->stage = DROP_REFERENCE;
9106         wc->update_ref = 0;
9107         wc->keep_locks = 1;
9108         wc->for_reloc = 1;
9109         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
9110
9111         while (1) {
9112                 wret = walk_down_tree(trans, root, path, wc);
9113                 if (wret < 0) {
9114                         ret = wret;
9115                         break;
9116                 }
9117
9118                 wret = walk_up_tree(trans, root, path, wc, parent_level);
9119                 if (wret < 0)
9120                         ret = wret;
9121                 if (wret != 0)
9122                         break;
9123         }
9124
9125         kfree(wc);
9126         btrfs_free_path(path);
9127         return ret;
9128 }
9129
9130 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
9131 {
9132         u64 num_devices;
9133         u64 stripped;
9134
9135         /*
9136          * if restripe for this chunk_type is on pick target profile and
9137          * return, otherwise do the usual balance
9138          */
9139         stripped = get_restripe_target(root->fs_info, flags);
9140         if (stripped)
9141                 return extended_to_chunk(stripped);
9142
9143         num_devices = root->fs_info->fs_devices->rw_devices;
9144
9145         stripped = BTRFS_BLOCK_GROUP_RAID0 |
9146                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
9147                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
9148
9149         if (num_devices == 1) {
9150                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9151                 stripped = flags & ~stripped;
9152
9153                 /* turn raid0 into single device chunks */
9154                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
9155                         return stripped;
9156
9157                 /* turn mirroring into duplication */
9158                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
9159                              BTRFS_BLOCK_GROUP_RAID10))
9160                         return stripped | BTRFS_BLOCK_GROUP_DUP;
9161         } else {
9162                 /* they already had raid on here, just return */
9163                 if (flags & stripped)
9164                         return flags;
9165
9166                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9167                 stripped = flags & ~stripped;
9168
9169                 /* switch duplicated blocks with raid1 */
9170                 if (flags & BTRFS_BLOCK_GROUP_DUP)
9171                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
9172
9173                 /* this is drive concat, leave it alone */
9174         }
9175
9176         return flags;
9177 }
9178
9179 static int inc_block_group_ro(struct btrfs_block_group_cache *cache, int force)
9180 {
9181         struct btrfs_space_info *sinfo = cache->space_info;
9182         u64 num_bytes;
9183         u64 min_allocable_bytes;
9184         int ret = -ENOSPC;
9185
9186         /*
9187          * We need some metadata space and system metadata space for
9188          * allocating chunks in some corner cases until we force to set
9189          * it to be readonly.
9190          */
9191         if ((sinfo->flags &
9192              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
9193             !force)
9194                 min_allocable_bytes = SZ_1M;
9195         else
9196                 min_allocable_bytes = 0;
9197
9198         spin_lock(&sinfo->lock);
9199         spin_lock(&cache->lock);
9200
9201         if (cache->ro) {
9202                 cache->ro++;
9203                 ret = 0;
9204                 goto out;
9205         }
9206
9207         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
9208                     cache->bytes_super - btrfs_block_group_used(&cache->item);
9209
9210         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
9211             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
9212             min_allocable_bytes <= sinfo->total_bytes) {
9213                 sinfo->bytes_readonly += num_bytes;
9214                 cache->ro++;
9215                 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
9216                 ret = 0;
9217         }
9218 out:
9219         spin_unlock(&cache->lock);
9220         spin_unlock(&sinfo->lock);
9221         return ret;
9222 }
9223
9224 int btrfs_inc_block_group_ro(struct btrfs_root *root,
9225                              struct btrfs_block_group_cache *cache)
9226
9227 {
9228         struct btrfs_trans_handle *trans;
9229         u64 alloc_flags;
9230         int ret;
9231
9232 again:
9233         trans = btrfs_join_transaction(root);
9234         if (IS_ERR(trans))
9235                 return PTR_ERR(trans);
9236
9237         /*
9238          * we're not allowed to set block groups readonly after the dirty
9239          * block groups cache has started writing.  If it already started,
9240          * back off and let this transaction commit
9241          */
9242         mutex_lock(&root->fs_info->ro_block_group_mutex);
9243         if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
9244                 u64 transid = trans->transid;
9245
9246                 mutex_unlock(&root->fs_info->ro_block_group_mutex);
9247                 btrfs_end_transaction(trans, root);
9248
9249                 ret = btrfs_wait_for_commit(root, transid);
9250                 if (ret)
9251                         return ret;
9252                 goto again;
9253         }
9254
9255         /*
9256          * if we are changing raid levels, try to allocate a corresponding
9257          * block group with the new raid level.
9258          */
9259         alloc_flags = update_block_group_flags(root, cache->flags);
9260         if (alloc_flags != cache->flags) {
9261                 ret = do_chunk_alloc(trans, root, alloc_flags,
9262                                      CHUNK_ALLOC_FORCE);
9263                 /*
9264                  * ENOSPC is allowed here, we may have enough space
9265                  * already allocated at the new raid level to
9266                  * carry on
9267                  */
9268                 if (ret == -ENOSPC)
9269                         ret = 0;
9270                 if (ret < 0)
9271                         goto out;
9272         }
9273
9274         ret = inc_block_group_ro(cache, 0);
9275         if (!ret)
9276                 goto out;
9277         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
9278         ret = do_chunk_alloc(trans, root, alloc_flags,
9279                              CHUNK_ALLOC_FORCE);
9280         if (ret < 0)
9281                 goto out;
9282         ret = inc_block_group_ro(cache, 0);
9283 out:
9284         if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
9285                 alloc_flags = update_block_group_flags(root, cache->flags);
9286                 lock_chunks(root->fs_info->chunk_root);
9287                 check_system_chunk(trans, root, alloc_flags);
9288                 unlock_chunks(root->fs_info->chunk_root);
9289         }
9290         mutex_unlock(&root->fs_info->ro_block_group_mutex);
9291
9292         btrfs_end_transaction(trans, root);
9293         return ret;
9294 }
9295
9296 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
9297                             struct btrfs_root *root, u64 type)
9298 {
9299         u64 alloc_flags = get_alloc_profile(root, type);
9300         return do_chunk_alloc(trans, root, alloc_flags,
9301                               CHUNK_ALLOC_FORCE);
9302 }
9303
9304 /*
9305  * helper to account the unused space of all the readonly block group in the
9306  * space_info. takes mirrors into account.
9307  */
9308 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
9309 {
9310         struct btrfs_block_group_cache *block_group;
9311         u64 free_bytes = 0;
9312         int factor;
9313
9314         /* It's df, we don't care if it's racey */
9315         if (list_empty(&sinfo->ro_bgs))
9316                 return 0;
9317
9318         spin_lock(&sinfo->lock);
9319         list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
9320                 spin_lock(&block_group->lock);
9321
9322                 if (!block_group->ro) {
9323                         spin_unlock(&block_group->lock);
9324                         continue;
9325                 }
9326
9327                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
9328                                           BTRFS_BLOCK_GROUP_RAID10 |
9329                                           BTRFS_BLOCK_GROUP_DUP))
9330                         factor = 2;
9331                 else
9332                         factor = 1;
9333
9334                 free_bytes += (block_group->key.offset -
9335                                btrfs_block_group_used(&block_group->item)) *
9336                                factor;
9337
9338                 spin_unlock(&block_group->lock);
9339         }
9340         spin_unlock(&sinfo->lock);
9341
9342         return free_bytes;
9343 }
9344
9345 void btrfs_dec_block_group_ro(struct btrfs_root *root,
9346                               struct btrfs_block_group_cache *cache)
9347 {
9348         struct btrfs_space_info *sinfo = cache->space_info;
9349         u64 num_bytes;
9350
9351         BUG_ON(!cache->ro);
9352
9353         spin_lock(&sinfo->lock);
9354         spin_lock(&cache->lock);
9355         if (!--cache->ro) {
9356                 num_bytes = cache->key.offset - cache->reserved -
9357                             cache->pinned - cache->bytes_super -
9358                             btrfs_block_group_used(&cache->item);
9359                 sinfo->bytes_readonly -= num_bytes;
9360                 list_del_init(&cache->ro_list);
9361         }
9362         spin_unlock(&cache->lock);
9363         spin_unlock(&sinfo->lock);
9364 }
9365
9366 /*
9367  * checks to see if its even possible to relocate this block group.
9368  *
9369  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
9370  * ok to go ahead and try.
9371  */
9372 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
9373 {
9374         struct btrfs_block_group_cache *block_group;
9375         struct btrfs_space_info *space_info;
9376         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
9377         struct btrfs_device *device;
9378         struct btrfs_trans_handle *trans;
9379         u64 min_free;
9380         u64 dev_min = 1;
9381         u64 dev_nr = 0;
9382         u64 target;
9383         int index;
9384         int full = 0;
9385         int ret = 0;
9386
9387         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
9388
9389         /* odd, couldn't find the block group, leave it alone */
9390         if (!block_group)
9391                 return -1;
9392
9393         min_free = btrfs_block_group_used(&block_group->item);
9394
9395         /* no bytes used, we're good */
9396         if (!min_free)
9397                 goto out;
9398
9399         space_info = block_group->space_info;
9400         spin_lock(&space_info->lock);
9401
9402         full = space_info->full;
9403
9404         /*
9405          * if this is the last block group we have in this space, we can't
9406          * relocate it unless we're able to allocate a new chunk below.
9407          *
9408          * Otherwise, we need to make sure we have room in the space to handle
9409          * all of the extents from this block group.  If we can, we're good
9410          */
9411         if ((space_info->total_bytes != block_group->key.offset) &&
9412             (space_info->bytes_used + space_info->bytes_reserved +
9413              space_info->bytes_pinned + space_info->bytes_readonly +
9414              min_free < space_info->total_bytes)) {
9415                 spin_unlock(&space_info->lock);
9416                 goto out;
9417         }
9418         spin_unlock(&space_info->lock);
9419
9420         /*
9421          * ok we don't have enough space, but maybe we have free space on our
9422          * devices to allocate new chunks for relocation, so loop through our
9423          * alloc devices and guess if we have enough space.  if this block
9424          * group is going to be restriped, run checks against the target
9425          * profile instead of the current one.
9426          */
9427         ret = -1;
9428
9429         /*
9430          * index:
9431          *      0: raid10
9432          *      1: raid1
9433          *      2: dup
9434          *      3: raid0
9435          *      4: single
9436          */
9437         target = get_restripe_target(root->fs_info, block_group->flags);
9438         if (target) {
9439                 index = __get_raid_index(extended_to_chunk(target));
9440         } else {
9441                 /*
9442                  * this is just a balance, so if we were marked as full
9443                  * we know there is no space for a new chunk
9444                  */
9445                 if (full)
9446                         goto out;
9447
9448                 index = get_block_group_index(block_group);
9449         }
9450
9451         if (index == BTRFS_RAID_RAID10) {
9452                 dev_min = 4;
9453                 /* Divide by 2 */
9454                 min_free >>= 1;
9455         } else if (index == BTRFS_RAID_RAID1) {
9456                 dev_min = 2;
9457         } else if (index == BTRFS_RAID_DUP) {
9458                 /* Multiply by 2 */
9459                 min_free <<= 1;
9460         } else if (index == BTRFS_RAID_RAID0) {
9461                 dev_min = fs_devices->rw_devices;
9462                 min_free = div64_u64(min_free, dev_min);
9463         }
9464
9465         /* We need to do this so that we can look at pending chunks */
9466         trans = btrfs_join_transaction(root);
9467         if (IS_ERR(trans)) {
9468                 ret = PTR_ERR(trans);
9469                 goto out;
9470         }
9471
9472         mutex_lock(&root->fs_info->chunk_mutex);
9473         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
9474                 u64 dev_offset;
9475
9476                 /*
9477                  * check to make sure we can actually find a chunk with enough
9478                  * space to fit our block group in.
9479                  */
9480                 if (device->total_bytes > device->bytes_used + min_free &&
9481                     !device->is_tgtdev_for_dev_replace) {
9482                         ret = find_free_dev_extent(trans, device, min_free,
9483                                                    &dev_offset, NULL);
9484                         if (!ret)
9485                                 dev_nr++;
9486
9487                         if (dev_nr >= dev_min)
9488                                 break;
9489
9490                         ret = -1;
9491                 }
9492         }
9493         mutex_unlock(&root->fs_info->chunk_mutex);
9494         btrfs_end_transaction(trans, root);
9495 out:
9496         btrfs_put_block_group(block_group);
9497         return ret;
9498 }
9499
9500 static int find_first_block_group(struct btrfs_root *root,
9501                 struct btrfs_path *path, struct btrfs_key *key)
9502 {
9503         int ret = 0;
9504         struct btrfs_key found_key;
9505         struct extent_buffer *leaf;
9506         int slot;
9507
9508         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
9509         if (ret < 0)
9510                 goto out;
9511
9512         while (1) {
9513                 slot = path->slots[0];
9514                 leaf = path->nodes[0];
9515                 if (slot >= btrfs_header_nritems(leaf)) {
9516                         ret = btrfs_next_leaf(root, path);
9517                         if (ret == 0)
9518                                 continue;
9519                         if (ret < 0)
9520                                 goto out;
9521                         break;
9522                 }
9523                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
9524
9525                 if (found_key.objectid >= key->objectid &&
9526                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
9527                         ret = 0;
9528                         goto out;
9529                 }
9530                 path->slots[0]++;
9531         }
9532 out:
9533         return ret;
9534 }
9535
9536 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
9537 {
9538         struct btrfs_block_group_cache *block_group;
9539         u64 last = 0;
9540
9541         while (1) {
9542                 struct inode *inode;
9543
9544                 block_group = btrfs_lookup_first_block_group(info, last);
9545                 while (block_group) {
9546                         spin_lock(&block_group->lock);
9547                         if (block_group->iref)
9548                                 break;
9549                         spin_unlock(&block_group->lock);
9550                         block_group = next_block_group(info->tree_root,
9551                                                        block_group);
9552                 }
9553                 if (!block_group) {
9554                         if (last == 0)
9555                                 break;
9556                         last = 0;
9557                         continue;
9558                 }
9559
9560                 inode = block_group->inode;
9561                 block_group->iref = 0;
9562                 block_group->inode = NULL;
9563                 spin_unlock(&block_group->lock);
9564                 iput(inode);
9565                 last = block_group->key.objectid + block_group->key.offset;
9566                 btrfs_put_block_group(block_group);
9567         }
9568 }
9569
9570 int btrfs_free_block_groups(struct btrfs_fs_info *info)
9571 {
9572         struct btrfs_block_group_cache *block_group;
9573         struct btrfs_space_info *space_info;
9574         struct btrfs_caching_control *caching_ctl;
9575         struct rb_node *n;
9576
9577         down_write(&info->commit_root_sem);
9578         while (!list_empty(&info->caching_block_groups)) {
9579                 caching_ctl = list_entry(info->caching_block_groups.next,
9580                                          struct btrfs_caching_control, list);
9581                 list_del(&caching_ctl->list);
9582                 put_caching_control(caching_ctl);
9583         }
9584         up_write(&info->commit_root_sem);
9585
9586         spin_lock(&info->unused_bgs_lock);
9587         while (!list_empty(&info->unused_bgs)) {
9588                 block_group = list_first_entry(&info->unused_bgs,
9589                                                struct btrfs_block_group_cache,
9590                                                bg_list);
9591                 list_del_init(&block_group->bg_list);
9592                 btrfs_put_block_group(block_group);
9593         }
9594         spin_unlock(&info->unused_bgs_lock);
9595
9596         spin_lock(&info->block_group_cache_lock);
9597         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
9598                 block_group = rb_entry(n, struct btrfs_block_group_cache,
9599                                        cache_node);
9600                 rb_erase(&block_group->cache_node,
9601                          &info->block_group_cache_tree);
9602                 RB_CLEAR_NODE(&block_group->cache_node);
9603                 spin_unlock(&info->block_group_cache_lock);
9604
9605                 down_write(&block_group->space_info->groups_sem);
9606                 list_del(&block_group->list);
9607                 up_write(&block_group->space_info->groups_sem);
9608
9609                 if (block_group->cached == BTRFS_CACHE_STARTED)
9610                         wait_block_group_cache_done(block_group);
9611
9612                 /*
9613                  * We haven't cached this block group, which means we could
9614                  * possibly have excluded extents on this block group.
9615                  */
9616                 if (block_group->cached == BTRFS_CACHE_NO ||
9617                     block_group->cached == BTRFS_CACHE_ERROR)
9618                         free_excluded_extents(info->extent_root, block_group);
9619
9620                 btrfs_remove_free_space_cache(block_group);
9621                 btrfs_put_block_group(block_group);
9622
9623                 spin_lock(&info->block_group_cache_lock);
9624         }
9625         spin_unlock(&info->block_group_cache_lock);
9626
9627         /* now that all the block groups are freed, go through and
9628          * free all the space_info structs.  This is only called during
9629          * the final stages of unmount, and so we know nobody is
9630          * using them.  We call synchronize_rcu() once before we start,
9631          * just to be on the safe side.
9632          */
9633         synchronize_rcu();
9634
9635         release_global_block_rsv(info);
9636
9637         while (!list_empty(&info->space_info)) {
9638                 int i;
9639
9640                 space_info = list_entry(info->space_info.next,
9641                                         struct btrfs_space_info,
9642                                         list);
9643                 if (btrfs_test_opt(info->tree_root, ENOSPC_DEBUG)) {
9644                         if (WARN_ON(space_info->bytes_pinned > 0 ||
9645                             space_info->bytes_reserved > 0 ||
9646                             space_info->bytes_may_use > 0)) {
9647                                 dump_space_info(space_info, 0, 0);
9648                         }
9649                 }
9650                 list_del(&space_info->list);
9651                 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
9652                         struct kobject *kobj;
9653                         kobj = space_info->block_group_kobjs[i];
9654                         space_info->block_group_kobjs[i] = NULL;
9655                         if (kobj) {
9656                                 kobject_del(kobj);
9657                                 kobject_put(kobj);
9658                         }
9659                 }
9660                 kobject_del(&space_info->kobj);
9661                 kobject_put(&space_info->kobj);
9662         }
9663         return 0;
9664 }
9665
9666 static void __link_block_group(struct btrfs_space_info *space_info,
9667                                struct btrfs_block_group_cache *cache)
9668 {
9669         int index = get_block_group_index(cache);
9670         bool first = false;
9671
9672         down_write(&space_info->groups_sem);
9673         if (list_empty(&space_info->block_groups[index]))
9674                 first = true;
9675         list_add_tail(&cache->list, &space_info->block_groups[index]);
9676         up_write(&space_info->groups_sem);
9677
9678         if (first) {
9679                 struct raid_kobject *rkobj;
9680                 int ret;
9681
9682                 rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
9683                 if (!rkobj)
9684                         goto out_err;
9685                 rkobj->raid_type = index;
9686                 kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
9687                 ret = kobject_add(&rkobj->kobj, &space_info->kobj,
9688                                   "%s", get_raid_name(index));
9689                 if (ret) {
9690                         kobject_put(&rkobj->kobj);
9691                         goto out_err;
9692                 }
9693                 space_info->block_group_kobjs[index] = &rkobj->kobj;
9694         }
9695
9696         return;
9697 out_err:
9698         pr_warn("BTRFS: failed to add kobject for block cache. ignoring.\n");
9699 }
9700
9701 static struct btrfs_block_group_cache *
9702 btrfs_create_block_group_cache(struct btrfs_root *root, u64 start, u64 size)
9703 {
9704         struct btrfs_block_group_cache *cache;
9705
9706         cache = kzalloc(sizeof(*cache), GFP_NOFS);
9707         if (!cache)
9708                 return NULL;
9709
9710         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
9711                                         GFP_NOFS);
9712         if (!cache->free_space_ctl) {
9713                 kfree(cache);
9714                 return NULL;
9715         }
9716
9717         cache->key.objectid = start;
9718         cache->key.offset = size;
9719         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
9720
9721         cache->sectorsize = root->sectorsize;
9722         cache->fs_info = root->fs_info;
9723         cache->full_stripe_len = btrfs_full_stripe_len(root,
9724                                                &root->fs_info->mapping_tree,
9725                                                start);
9726         set_free_space_tree_thresholds(cache);
9727
9728         atomic_set(&cache->count, 1);
9729         spin_lock_init(&cache->lock);
9730         init_rwsem(&cache->data_rwsem);
9731         INIT_LIST_HEAD(&cache->list);
9732         INIT_LIST_HEAD(&cache->cluster_list);
9733         INIT_LIST_HEAD(&cache->bg_list);
9734         INIT_LIST_HEAD(&cache->ro_list);
9735         INIT_LIST_HEAD(&cache->dirty_list);
9736         INIT_LIST_HEAD(&cache->io_list);
9737         btrfs_init_free_space_ctl(cache);
9738         atomic_set(&cache->trimming, 0);
9739         mutex_init(&cache->free_space_lock);
9740
9741         return cache;
9742 }
9743
9744 int btrfs_read_block_groups(struct btrfs_root *root)
9745 {
9746         struct btrfs_path *path;
9747         int ret;
9748         struct btrfs_block_group_cache *cache;
9749         struct btrfs_fs_info *info = root->fs_info;
9750         struct btrfs_space_info *space_info;
9751         struct btrfs_key key;
9752         struct btrfs_key found_key;
9753         struct extent_buffer *leaf;
9754         int need_clear = 0;
9755         u64 cache_gen;
9756
9757         root = info->extent_root;
9758         key.objectid = 0;
9759         key.offset = 0;
9760         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
9761         path = btrfs_alloc_path();
9762         if (!path)
9763                 return -ENOMEM;
9764         path->reada = READA_FORWARD;
9765
9766         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
9767         if (btrfs_test_opt(root, SPACE_CACHE) &&
9768             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
9769                 need_clear = 1;
9770         if (btrfs_test_opt(root, CLEAR_CACHE))
9771                 need_clear = 1;
9772
9773         while (1) {
9774                 ret = find_first_block_group(root, path, &key);
9775                 if (ret > 0)
9776                         break;
9777                 if (ret != 0)
9778                         goto error;
9779
9780                 leaf = path->nodes[0];
9781                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
9782
9783                 cache = btrfs_create_block_group_cache(root, found_key.objectid,
9784                                                        found_key.offset);
9785                 if (!cache) {
9786                         ret = -ENOMEM;
9787                         goto error;
9788                 }
9789
9790                 if (need_clear) {
9791                         /*
9792                          * When we mount with old space cache, we need to
9793                          * set BTRFS_DC_CLEAR and set dirty flag.
9794                          *
9795                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
9796                          *    truncate the old free space cache inode and
9797                          *    setup a new one.
9798                          * b) Setting 'dirty flag' makes sure that we flush
9799                          *    the new space cache info onto disk.
9800                          */
9801                         if (btrfs_test_opt(root, SPACE_CACHE))
9802                                 cache->disk_cache_state = BTRFS_DC_CLEAR;
9803                 }
9804
9805                 read_extent_buffer(leaf, &cache->item,
9806                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
9807                                    sizeof(cache->item));
9808                 cache->flags = btrfs_block_group_flags(&cache->item);
9809
9810                 key.objectid = found_key.objectid + found_key.offset;
9811                 btrfs_release_path(path);
9812
9813                 /*
9814                  * We need to exclude the super stripes now so that the space
9815                  * info has super bytes accounted for, otherwise we'll think
9816                  * we have more space than we actually do.
9817                  */
9818                 ret = exclude_super_stripes(root, cache);
9819                 if (ret) {
9820                         /*
9821                          * We may have excluded something, so call this just in
9822                          * case.
9823                          */
9824                         free_excluded_extents(root, cache);
9825                         btrfs_put_block_group(cache);
9826                         goto error;
9827                 }
9828
9829                 /*
9830                  * check for two cases, either we are full, and therefore
9831                  * don't need to bother with the caching work since we won't
9832                  * find any space, or we are empty, and we can just add all
9833                  * the space in and be done with it.  This saves us _alot_ of
9834                  * time, particularly in the full case.
9835                  */
9836                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
9837                         cache->last_byte_to_unpin = (u64)-1;
9838                         cache->cached = BTRFS_CACHE_FINISHED;
9839                         free_excluded_extents(root, cache);
9840                 } else if (btrfs_block_group_used(&cache->item) == 0) {
9841                         cache->last_byte_to_unpin = (u64)-1;
9842                         cache->cached = BTRFS_CACHE_FINISHED;
9843                         add_new_free_space(cache, root->fs_info,
9844                                            found_key.objectid,
9845                                            found_key.objectid +
9846                                            found_key.offset);
9847                         free_excluded_extents(root, cache);
9848                 }
9849
9850                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
9851                 if (ret) {
9852                         btrfs_remove_free_space_cache(cache);
9853                         btrfs_put_block_group(cache);
9854                         goto error;
9855                 }
9856
9857                 ret = update_space_info(info, cache->flags, found_key.offset,
9858                                         btrfs_block_group_used(&cache->item),
9859                                         &space_info);
9860                 if (ret) {
9861                         btrfs_remove_free_space_cache(cache);
9862                         spin_lock(&info->block_group_cache_lock);
9863                         rb_erase(&cache->cache_node,
9864                                  &info->block_group_cache_tree);
9865                         RB_CLEAR_NODE(&cache->cache_node);
9866                         spin_unlock(&info->block_group_cache_lock);
9867                         btrfs_put_block_group(cache);
9868                         goto error;
9869                 }
9870
9871                 cache->space_info = space_info;
9872                 spin_lock(&cache->space_info->lock);
9873                 cache->space_info->bytes_readonly += cache->bytes_super;
9874                 spin_unlock(&cache->space_info->lock);
9875
9876                 __link_block_group(space_info, cache);
9877
9878                 set_avail_alloc_bits(root->fs_info, cache->flags);
9879                 if (btrfs_chunk_readonly(root, cache->key.objectid)) {
9880                         inc_block_group_ro(cache, 1);
9881                 } else if (btrfs_block_group_used(&cache->item) == 0) {
9882                         spin_lock(&info->unused_bgs_lock);
9883                         /* Should always be true but just in case. */
9884                         if (list_empty(&cache->bg_list)) {
9885                                 btrfs_get_block_group(cache);
9886                                 list_add_tail(&cache->bg_list,
9887                                               &info->unused_bgs);
9888                         }
9889                         spin_unlock(&info->unused_bgs_lock);
9890                 }
9891         }
9892
9893         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
9894                 if (!(get_alloc_profile(root, space_info->flags) &
9895                       (BTRFS_BLOCK_GROUP_RAID10 |
9896                        BTRFS_BLOCK_GROUP_RAID1 |
9897                        BTRFS_BLOCK_GROUP_RAID5 |
9898                        BTRFS_BLOCK_GROUP_RAID6 |
9899                        BTRFS_BLOCK_GROUP_DUP)))
9900                         continue;
9901                 /*
9902                  * avoid allocating from un-mirrored block group if there are
9903                  * mirrored block groups.
9904                  */
9905                 list_for_each_entry(cache,
9906                                 &space_info->block_groups[BTRFS_RAID_RAID0],
9907                                 list)
9908                         inc_block_group_ro(cache, 1);
9909                 list_for_each_entry(cache,
9910                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
9911                                 list)
9912                         inc_block_group_ro(cache, 1);
9913         }
9914
9915         init_global_block_rsv(info);
9916         ret = 0;
9917 error:
9918         btrfs_free_path(path);
9919         return ret;
9920 }
9921
9922 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
9923                                        struct btrfs_root *root)
9924 {
9925         struct btrfs_block_group_cache *block_group, *tmp;
9926         struct btrfs_root *extent_root = root->fs_info->extent_root;
9927         struct btrfs_block_group_item item;
9928         struct btrfs_key key;
9929         int ret = 0;
9930         bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
9931
9932         trans->can_flush_pending_bgs = false;
9933         list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
9934                 if (ret)
9935                         goto next;
9936
9937                 spin_lock(&block_group->lock);
9938                 memcpy(&item, &block_group->item, sizeof(item));
9939                 memcpy(&key, &block_group->key, sizeof(key));
9940                 spin_unlock(&block_group->lock);
9941
9942                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
9943                                         sizeof(item));
9944                 if (ret)
9945                         btrfs_abort_transaction(trans, extent_root, ret);
9946                 ret = btrfs_finish_chunk_alloc(trans, extent_root,
9947                                                key.objectid, key.offset);
9948                 if (ret)
9949                         btrfs_abort_transaction(trans, extent_root, ret);
9950                 add_block_group_free_space(trans, root->fs_info, block_group);
9951                 /* already aborted the transaction if it failed. */
9952 next:
9953                 list_del_init(&block_group->bg_list);
9954         }
9955         trans->can_flush_pending_bgs = can_flush_pending_bgs;
9956 }
9957
9958 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
9959                            struct btrfs_root *root, u64 bytes_used,
9960                            u64 type, u64 chunk_objectid, u64 chunk_offset,
9961                            u64 size)
9962 {
9963         int ret;
9964         struct btrfs_root *extent_root;
9965         struct btrfs_block_group_cache *cache;
9966
9967         extent_root = root->fs_info->extent_root;
9968
9969         btrfs_set_log_full_commit(root->fs_info, trans);
9970
9971         cache = btrfs_create_block_group_cache(root, chunk_offset, size);
9972         if (!cache)
9973                 return -ENOMEM;
9974
9975         btrfs_set_block_group_used(&cache->item, bytes_used);
9976         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
9977         btrfs_set_block_group_flags(&cache->item, type);
9978
9979         cache->flags = type;
9980         cache->last_byte_to_unpin = (u64)-1;
9981         cache->cached = BTRFS_CACHE_FINISHED;
9982         cache->needs_free_space = 1;
9983         ret = exclude_super_stripes(root, cache);
9984         if (ret) {
9985                 /*
9986                  * We may have excluded something, so call this just in
9987                  * case.
9988                  */
9989                 free_excluded_extents(root, cache);
9990                 btrfs_put_block_group(cache);
9991                 return ret;
9992         }
9993
9994         add_new_free_space(cache, root->fs_info, chunk_offset,
9995                            chunk_offset + size);
9996
9997         free_excluded_extents(root, cache);
9998
9999 #ifdef CONFIG_BTRFS_DEBUG
10000         if (btrfs_should_fragment_free_space(root, cache)) {
10001                 u64 new_bytes_used = size - bytes_used;
10002
10003                 bytes_used += new_bytes_used >> 1;
10004                 fragment_free_space(root, cache);
10005         }
10006 #endif
10007         /*
10008          * Call to ensure the corresponding space_info object is created and
10009          * assigned to our block group, but don't update its counters just yet.
10010          * We want our bg to be added to the rbtree with its ->space_info set.
10011          */
10012         ret = update_space_info(root->fs_info, cache->flags, 0, 0,
10013                                 &cache->space_info);
10014         if (ret) {
10015                 btrfs_remove_free_space_cache(cache);
10016                 btrfs_put_block_group(cache);
10017                 return ret;
10018         }
10019
10020         ret = btrfs_add_block_group_cache(root->fs_info, cache);
10021         if (ret) {
10022                 btrfs_remove_free_space_cache(cache);
10023                 btrfs_put_block_group(cache);
10024                 return ret;
10025         }
10026
10027         /*
10028          * Now that our block group has its ->space_info set and is inserted in
10029          * the rbtree, update the space info's counters.
10030          */
10031         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
10032                                 &cache->space_info);
10033         if (ret) {
10034                 btrfs_remove_free_space_cache(cache);
10035                 spin_lock(&root->fs_info->block_group_cache_lock);
10036                 rb_erase(&cache->cache_node,
10037                          &root->fs_info->block_group_cache_tree);
10038                 RB_CLEAR_NODE(&cache->cache_node);
10039                 spin_unlock(&root->fs_info->block_group_cache_lock);
10040                 btrfs_put_block_group(cache);
10041                 return ret;
10042         }
10043         update_global_block_rsv(root->fs_info);
10044
10045         spin_lock(&cache->space_info->lock);
10046         cache->space_info->bytes_readonly += cache->bytes_super;
10047         spin_unlock(&cache->space_info->lock);
10048
10049         __link_block_group(cache->space_info, cache);
10050
10051         list_add_tail(&cache->bg_list, &trans->new_bgs);
10052
10053         set_avail_alloc_bits(extent_root->fs_info, type);
10054
10055         return 0;
10056 }
10057
10058 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
10059 {
10060         u64 extra_flags = chunk_to_extended(flags) &
10061                                 BTRFS_EXTENDED_PROFILE_MASK;
10062
10063         write_seqlock(&fs_info->profiles_lock);
10064         if (flags & BTRFS_BLOCK_GROUP_DATA)
10065                 fs_info->avail_data_alloc_bits &= ~extra_flags;
10066         if (flags & BTRFS_BLOCK_GROUP_METADATA)
10067                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
10068         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
10069                 fs_info->avail_system_alloc_bits &= ~extra_flags;
10070         write_sequnlock(&fs_info->profiles_lock);
10071 }
10072
10073 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
10074                              struct btrfs_root *root, u64 group_start,
10075                              struct extent_map *em)
10076 {
10077         struct btrfs_path *path;
10078         struct btrfs_block_group_cache *block_group;
10079         struct btrfs_free_cluster *cluster;
10080         struct btrfs_root *tree_root = root->fs_info->tree_root;
10081         struct btrfs_key key;
10082         struct inode *inode;
10083         struct kobject *kobj = NULL;
10084         int ret;
10085         int index;
10086         int factor;
10087         struct btrfs_caching_control *caching_ctl = NULL;
10088         bool remove_em;
10089
10090         root = root->fs_info->extent_root;
10091
10092         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
10093         BUG_ON(!block_group);
10094         BUG_ON(!block_group->ro);
10095
10096         /*
10097          * Free the reserved super bytes from this block group before
10098          * remove it.
10099          */
10100         free_excluded_extents(root, block_group);
10101
10102         memcpy(&key, &block_group->key, sizeof(key));
10103         index = get_block_group_index(block_group);
10104         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
10105                                   BTRFS_BLOCK_GROUP_RAID1 |
10106                                   BTRFS_BLOCK_GROUP_RAID10))
10107                 factor = 2;
10108         else
10109                 factor = 1;
10110
10111         /* make sure this block group isn't part of an allocation cluster */
10112         cluster = &root->fs_info->data_alloc_cluster;
10113         spin_lock(&cluster->refill_lock);
10114         btrfs_return_cluster_to_free_space(block_group, cluster);
10115         spin_unlock(&cluster->refill_lock);
10116
10117         /*
10118          * make sure this block group isn't part of a metadata
10119          * allocation cluster
10120          */
10121         cluster = &root->fs_info->meta_alloc_cluster;
10122         spin_lock(&cluster->refill_lock);
10123         btrfs_return_cluster_to_free_space(block_group, cluster);
10124         spin_unlock(&cluster->refill_lock);
10125
10126         path = btrfs_alloc_path();
10127         if (!path) {
10128                 ret = -ENOMEM;
10129                 goto out;
10130         }
10131
10132         /*
10133          * get the inode first so any iput calls done for the io_list
10134          * aren't the final iput (no unlinks allowed now)
10135          */
10136         inode = lookup_free_space_inode(tree_root, block_group, path);
10137
10138         mutex_lock(&trans->transaction->cache_write_mutex);
10139         /*
10140          * make sure our free spache cache IO is done before remove the
10141          * free space inode
10142          */
10143         spin_lock(&trans->transaction->dirty_bgs_lock);
10144         if (!list_empty(&block_group->io_list)) {
10145                 list_del_init(&block_group->io_list);
10146
10147                 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
10148
10149                 spin_unlock(&trans->transaction->dirty_bgs_lock);
10150                 btrfs_wait_cache_io(root, trans, block_group,
10151                                     &block_group->io_ctl, path,
10152                                     block_group->key.objectid);
10153                 btrfs_put_block_group(block_group);
10154                 spin_lock(&trans->transaction->dirty_bgs_lock);
10155         }
10156
10157         if (!list_empty(&block_group->dirty_list)) {
10158                 list_del_init(&block_group->dirty_list);
10159                 btrfs_put_block_group(block_group);
10160         }
10161         spin_unlock(&trans->transaction->dirty_bgs_lock);
10162         mutex_unlock(&trans->transaction->cache_write_mutex);
10163
10164         if (!IS_ERR(inode)) {
10165                 ret = btrfs_orphan_add(trans, inode);
10166                 if (ret) {
10167                         btrfs_add_delayed_iput(inode);
10168                         goto out;
10169                 }
10170                 clear_nlink(inode);
10171                 /* One for the block groups ref */
10172                 spin_lock(&block_group->lock);
10173                 if (block_group->iref) {
10174                         block_group->iref = 0;
10175                         block_group->inode = NULL;
10176                         spin_unlock(&block_group->lock);
10177                         iput(inode);
10178                 } else {
10179                         spin_unlock(&block_group->lock);
10180                 }
10181                 /* One for our lookup ref */
10182                 btrfs_add_delayed_iput(inode);
10183         }
10184
10185         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
10186         key.offset = block_group->key.objectid;
10187         key.type = 0;
10188
10189         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
10190         if (ret < 0)
10191                 goto out;
10192         if (ret > 0)
10193                 btrfs_release_path(path);
10194         if (ret == 0) {
10195                 ret = btrfs_del_item(trans, tree_root, path);
10196                 if (ret)
10197                         goto out;
10198                 btrfs_release_path(path);
10199         }
10200
10201         spin_lock(&root->fs_info->block_group_cache_lock);
10202         rb_erase(&block_group->cache_node,
10203                  &root->fs_info->block_group_cache_tree);
10204         RB_CLEAR_NODE(&block_group->cache_node);
10205
10206         if (root->fs_info->first_logical_byte == block_group->key.objectid)
10207                 root->fs_info->first_logical_byte = (u64)-1;
10208         spin_unlock(&root->fs_info->block_group_cache_lock);
10209
10210         down_write(&block_group->space_info->groups_sem);
10211         /*
10212          * we must use list_del_init so people can check to see if they
10213          * are still on the list after taking the semaphore
10214          */
10215         list_del_init(&block_group->list);
10216         if (list_empty(&block_group->space_info->block_groups[index])) {
10217                 kobj = block_group->space_info->block_group_kobjs[index];
10218                 block_group->space_info->block_group_kobjs[index] = NULL;
10219                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
10220         }
10221         up_write(&block_group->space_info->groups_sem);
10222         if (kobj) {
10223                 kobject_del(kobj);
10224                 kobject_put(kobj);
10225         }
10226
10227         if (block_group->has_caching_ctl)
10228                 caching_ctl = get_caching_control(block_group);
10229         if (block_group->cached == BTRFS_CACHE_STARTED)
10230                 wait_block_group_cache_done(block_group);
10231         if (block_group->has_caching_ctl) {
10232                 down_write(&root->fs_info->commit_root_sem);
10233                 if (!caching_ctl) {
10234                         struct btrfs_caching_control *ctl;
10235
10236                         list_for_each_entry(ctl,
10237                                     &root->fs_info->caching_block_groups, list)
10238                                 if (ctl->block_group == block_group) {
10239                                         caching_ctl = ctl;
10240                                         atomic_inc(&caching_ctl->count);
10241                                         break;
10242                                 }
10243                 }
10244                 if (caching_ctl)
10245                         list_del_init(&caching_ctl->list);
10246                 up_write(&root->fs_info->commit_root_sem);
10247                 if (caching_ctl) {
10248                         /* Once for the caching bgs list and once for us. */
10249                         put_caching_control(caching_ctl);
10250                         put_caching_control(caching_ctl);
10251                 }
10252         }
10253
10254         spin_lock(&trans->transaction->dirty_bgs_lock);
10255         if (!list_empty(&block_group->dirty_list)) {
10256                 WARN_ON(1);
10257         }
10258         if (!list_empty(&block_group->io_list)) {
10259                 WARN_ON(1);
10260         }
10261         spin_unlock(&trans->transaction->dirty_bgs_lock);
10262         btrfs_remove_free_space_cache(block_group);
10263
10264         spin_lock(&block_group->space_info->lock);
10265         list_del_init(&block_group->ro_list);
10266
10267         if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
10268                 WARN_ON(block_group->space_info->total_bytes
10269                         < block_group->key.offset);
10270                 WARN_ON(block_group->space_info->bytes_readonly
10271                         < block_group->key.offset);
10272                 WARN_ON(block_group->space_info->disk_total
10273                         < block_group->key.offset * factor);
10274         }
10275         block_group->space_info->total_bytes -= block_group->key.offset;
10276         block_group->space_info->bytes_readonly -= block_group->key.offset;
10277         block_group->space_info->disk_total -= block_group->key.offset * factor;
10278
10279         spin_unlock(&block_group->space_info->lock);
10280
10281         memcpy(&key, &block_group->key, sizeof(key));
10282
10283         lock_chunks(root);
10284         if (!list_empty(&em->list)) {
10285                 /* We're in the transaction->pending_chunks list. */
10286                 free_extent_map(em);
10287         }
10288         spin_lock(&block_group->lock);
10289         block_group->removed = 1;
10290         /*
10291          * At this point trimming can't start on this block group, because we
10292          * removed the block group from the tree fs_info->block_group_cache_tree
10293          * so no one can't find it anymore and even if someone already got this
10294          * block group before we removed it from the rbtree, they have already
10295          * incremented block_group->trimming - if they didn't, they won't find
10296          * any free space entries because we already removed them all when we
10297          * called btrfs_remove_free_space_cache().
10298          *
10299          * And we must not remove the extent map from the fs_info->mapping_tree
10300          * to prevent the same logical address range and physical device space
10301          * ranges from being reused for a new block group. This is because our
10302          * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
10303          * completely transactionless, so while it is trimming a range the
10304          * currently running transaction might finish and a new one start,
10305          * allowing for new block groups to be created that can reuse the same
10306          * physical device locations unless we take this special care.
10307          *
10308          * There may also be an implicit trim operation if the file system
10309          * is mounted with -odiscard. The same protections must remain
10310          * in place until the extents have been discarded completely when
10311          * the transaction commit has completed.
10312          */
10313         remove_em = (atomic_read(&block_group->trimming) == 0);
10314         /*
10315          * Make sure a trimmer task always sees the em in the pinned_chunks list
10316          * if it sees block_group->removed == 1 (needs to lock block_group->lock
10317          * before checking block_group->removed).
10318          */
10319         if (!remove_em) {
10320                 /*
10321                  * Our em might be in trans->transaction->pending_chunks which
10322                  * is protected by fs_info->chunk_mutex ([lock|unlock]_chunks),
10323                  * and so is the fs_info->pinned_chunks list.
10324                  *
10325                  * So at this point we must be holding the chunk_mutex to avoid
10326                  * any races with chunk allocation (more specifically at
10327                  * volumes.c:contains_pending_extent()), to ensure it always
10328                  * sees the em, either in the pending_chunks list or in the
10329                  * pinned_chunks list.
10330                  */
10331                 list_move_tail(&em->list, &root->fs_info->pinned_chunks);
10332         }
10333         spin_unlock(&block_group->lock);
10334
10335         if (remove_em) {
10336                 struct extent_map_tree *em_tree;
10337
10338                 em_tree = &root->fs_info->mapping_tree.map_tree;
10339                 write_lock(&em_tree->lock);
10340                 /*
10341                  * The em might be in the pending_chunks list, so make sure the
10342                  * chunk mutex is locked, since remove_extent_mapping() will
10343                  * delete us from that list.
10344                  */
10345                 remove_extent_mapping(em_tree, em);
10346                 write_unlock(&em_tree->lock);
10347                 /* once for the tree */
10348                 free_extent_map(em);
10349         }
10350
10351         unlock_chunks(root);
10352
10353         ret = remove_block_group_free_space(trans, root->fs_info, block_group);
10354         if (ret)
10355                 goto out;
10356
10357         btrfs_put_block_group(block_group);
10358         btrfs_put_block_group(block_group);
10359
10360         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
10361         if (ret > 0)
10362                 ret = -EIO;
10363         if (ret < 0)
10364                 goto out;
10365
10366         ret = btrfs_del_item(trans, root, path);
10367 out:
10368         btrfs_free_path(path);
10369         return ret;
10370 }
10371
10372 struct btrfs_trans_handle *
10373 btrfs_start_trans_remove_block_group(struct btrfs_fs_info *fs_info,
10374                                      const u64 chunk_offset)
10375 {
10376         struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree;
10377         struct extent_map *em;
10378         struct map_lookup *map;
10379         unsigned int num_items;
10380
10381         read_lock(&em_tree->lock);
10382         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
10383         read_unlock(&em_tree->lock);
10384         ASSERT(em && em->start == chunk_offset);
10385
10386         /*
10387          * We need to reserve 3 + N units from the metadata space info in order
10388          * to remove a block group (done at btrfs_remove_chunk() and at
10389          * btrfs_remove_block_group()), which are used for:
10390          *
10391          * 1 unit for adding the free space inode's orphan (located in the tree
10392          * of tree roots).
10393          * 1 unit for deleting the block group item (located in the extent
10394          * tree).
10395          * 1 unit for deleting the free space item (located in tree of tree
10396          * roots).
10397          * N units for deleting N device extent items corresponding to each
10398          * stripe (located in the device tree).
10399          *
10400          * In order to remove a block group we also need to reserve units in the
10401          * system space info in order to update the chunk tree (update one or
10402          * more device items and remove one chunk item), but this is done at
10403          * btrfs_remove_chunk() through a call to check_system_chunk().
10404          */
10405         map = em->map_lookup;
10406         num_items = 3 + map->num_stripes;
10407         free_extent_map(em);
10408
10409         return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
10410                                                            num_items, 1);
10411 }
10412
10413 /*
10414  * Process the unused_bgs list and remove any that don't have any allocated
10415  * space inside of them.
10416  */
10417 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
10418 {
10419         struct btrfs_block_group_cache *block_group;
10420         struct btrfs_space_info *space_info;
10421         struct btrfs_root *root = fs_info->extent_root;
10422         struct btrfs_trans_handle *trans;
10423         int ret = 0;
10424
10425         if (!fs_info->open)
10426                 return;
10427
10428         spin_lock(&fs_info->unused_bgs_lock);
10429         while (!list_empty(&fs_info->unused_bgs)) {
10430                 u64 start, end;
10431                 int trimming;
10432
10433                 block_group = list_first_entry(&fs_info->unused_bgs,
10434                                                struct btrfs_block_group_cache,
10435                                                bg_list);
10436                 list_del_init(&block_group->bg_list);
10437
10438                 space_info = block_group->space_info;
10439
10440                 if (ret || btrfs_mixed_space_info(space_info)) {
10441                         btrfs_put_block_group(block_group);
10442                         continue;
10443                 }
10444                 spin_unlock(&fs_info->unused_bgs_lock);
10445
10446                 mutex_lock(&fs_info->delete_unused_bgs_mutex);
10447
10448                 /* Don't want to race with allocators so take the groups_sem */
10449                 down_write(&space_info->groups_sem);
10450                 spin_lock(&block_group->lock);
10451                 if (block_group->reserved ||
10452                     btrfs_block_group_used(&block_group->item) ||
10453                     block_group->ro ||
10454                     list_is_singular(&block_group->list)) {
10455                         /*
10456                          * We want to bail if we made new allocations or have
10457                          * outstanding allocations in this block group.  We do
10458                          * the ro check in case balance is currently acting on
10459                          * this block group.
10460                          */
10461                         spin_unlock(&block_group->lock);
10462                         up_write(&space_info->groups_sem);
10463                         goto next;
10464                 }
10465                 spin_unlock(&block_group->lock);
10466
10467                 /* We don't want to force the issue, only flip if it's ok. */
10468                 ret = inc_block_group_ro(block_group, 0);
10469                 up_write(&space_info->groups_sem);
10470                 if (ret < 0) {
10471                         ret = 0;
10472                         goto next;
10473                 }
10474
10475                 /*
10476                  * Want to do this before we do anything else so we can recover
10477                  * properly if we fail to join the transaction.
10478                  */
10479                 trans = btrfs_start_trans_remove_block_group(fs_info,
10480                                                      block_group->key.objectid);
10481                 if (IS_ERR(trans)) {
10482                         btrfs_dec_block_group_ro(root, block_group);
10483                         ret = PTR_ERR(trans);
10484                         goto next;
10485                 }
10486
10487                 /*
10488                  * We could have pending pinned extents for this block group,
10489                  * just delete them, we don't care about them anymore.
10490                  */
10491                 start = block_group->key.objectid;
10492                 end = start + block_group->key.offset - 1;
10493                 /*
10494                  * Hold the unused_bg_unpin_mutex lock to avoid racing with
10495                  * btrfs_finish_extent_commit(). If we are at transaction N,
10496                  * another task might be running finish_extent_commit() for the
10497                  * previous transaction N - 1, and have seen a range belonging
10498                  * to the block group in freed_extents[] before we were able to
10499                  * clear the whole block group range from freed_extents[]. This
10500                  * means that task can lookup for the block group after we
10501                  * unpinned it from freed_extents[] and removed it, leading to
10502                  * a BUG_ON() at btrfs_unpin_extent_range().
10503                  */
10504                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
10505                 ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
10506                                   EXTENT_DIRTY, GFP_NOFS);
10507                 if (ret) {
10508                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10509                         btrfs_dec_block_group_ro(root, block_group);
10510                         goto end_trans;
10511                 }
10512                 ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
10513                                   EXTENT_DIRTY, GFP_NOFS);
10514                 if (ret) {
10515                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10516                         btrfs_dec_block_group_ro(root, block_group);
10517                         goto end_trans;
10518                 }
10519                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10520
10521                 /* Reset pinned so btrfs_put_block_group doesn't complain */
10522                 spin_lock(&space_info->lock);
10523                 spin_lock(&block_group->lock);
10524
10525                 space_info->bytes_pinned -= block_group->pinned;
10526                 space_info->bytes_readonly += block_group->pinned;
10527                 percpu_counter_add(&space_info->total_bytes_pinned,
10528                                    -block_group->pinned);
10529                 block_group->pinned = 0;
10530
10531                 spin_unlock(&block_group->lock);
10532                 spin_unlock(&space_info->lock);
10533
10534                 /* DISCARD can flip during remount */
10535                 trimming = btrfs_test_opt(root, DISCARD);
10536
10537                 /* Implicit trim during transaction commit. */
10538                 if (trimming)
10539                         btrfs_get_block_group_trimming(block_group);
10540
10541                 /*
10542                  * Btrfs_remove_chunk will abort the transaction if things go
10543                  * horribly wrong.
10544                  */
10545                 ret = btrfs_remove_chunk(trans, root,
10546                                          block_group->key.objectid);
10547
10548                 if (ret) {
10549                         if (trimming)
10550                                 btrfs_put_block_group_trimming(block_group);
10551                         goto end_trans;
10552                 }
10553
10554                 /*
10555                  * If we're not mounted with -odiscard, we can just forget
10556                  * about this block group. Otherwise we'll need to wait
10557                  * until transaction commit to do the actual discard.
10558                  */
10559                 if (trimming) {
10560                         spin_lock(&fs_info->unused_bgs_lock);
10561                         /*
10562                          * A concurrent scrub might have added us to the list
10563                          * fs_info->unused_bgs, so use a list_move operation
10564                          * to add the block group to the deleted_bgs list.
10565                          */
10566                         list_move(&block_group->bg_list,
10567                                   &trans->transaction->deleted_bgs);
10568                         spin_unlock(&fs_info->unused_bgs_lock);
10569                         btrfs_get_block_group(block_group);
10570                 }
10571 end_trans:
10572                 btrfs_end_transaction(trans, root);
10573 next:
10574                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
10575                 btrfs_put_block_group(block_group);
10576                 spin_lock(&fs_info->unused_bgs_lock);
10577         }
10578         spin_unlock(&fs_info->unused_bgs_lock);
10579 }
10580
10581 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
10582 {
10583         struct btrfs_space_info *space_info;
10584         struct btrfs_super_block *disk_super;
10585         u64 features;
10586         u64 flags;
10587         int mixed = 0;
10588         int ret;
10589
10590         disk_super = fs_info->super_copy;
10591         if (!btrfs_super_root(disk_super))
10592                 return -EINVAL;
10593
10594         features = btrfs_super_incompat_flags(disk_super);
10595         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
10596                 mixed = 1;
10597
10598         flags = BTRFS_BLOCK_GROUP_SYSTEM;
10599         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10600         if (ret)
10601                 goto out;
10602
10603         if (mixed) {
10604                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
10605                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10606         } else {
10607                 flags = BTRFS_BLOCK_GROUP_METADATA;
10608                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10609                 if (ret)
10610                         goto out;
10611
10612                 flags = BTRFS_BLOCK_GROUP_DATA;
10613                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10614         }
10615 out:
10616         return ret;
10617 }
10618
10619 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
10620 {
10621         return unpin_extent_range(root, start, end, false);
10622 }
10623
10624 /*
10625  * It used to be that old block groups would be left around forever.
10626  * Iterating over them would be enough to trim unused space.  Since we
10627  * now automatically remove them, we also need to iterate over unallocated
10628  * space.
10629  *
10630  * We don't want a transaction for this since the discard may take a
10631  * substantial amount of time.  We don't require that a transaction be
10632  * running, but we do need to take a running transaction into account
10633  * to ensure that we're not discarding chunks that were released in
10634  * the current transaction.
10635  *
10636  * Holding the chunks lock will prevent other threads from allocating
10637  * or releasing chunks, but it won't prevent a running transaction
10638  * from committing and releasing the memory that the pending chunks
10639  * list head uses.  For that, we need to take a reference to the
10640  * transaction.
10641  */
10642 static int btrfs_trim_free_extents(struct btrfs_device *device,
10643                                    u64 minlen, u64 *trimmed)
10644 {
10645         u64 start = 0, len = 0;
10646         int ret;
10647
10648         *trimmed = 0;
10649
10650         /* Not writeable = nothing to do. */
10651         if (!device->writeable)
10652                 return 0;
10653
10654         /* No free space = nothing to do. */
10655         if (device->total_bytes <= device->bytes_used)
10656                 return 0;
10657
10658         ret = 0;
10659
10660         while (1) {
10661                 struct btrfs_fs_info *fs_info = device->dev_root->fs_info;
10662                 struct btrfs_transaction *trans;
10663                 u64 bytes;
10664
10665                 ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
10666                 if (ret)
10667                         return ret;
10668
10669                 down_read(&fs_info->commit_root_sem);
10670
10671                 spin_lock(&fs_info->trans_lock);
10672                 trans = fs_info->running_transaction;
10673                 if (trans)
10674                         atomic_inc(&trans->use_count);
10675                 spin_unlock(&fs_info->trans_lock);
10676
10677                 ret = find_free_dev_extent_start(trans, device, minlen, start,
10678                                                  &start, &len);
10679                 if (trans)
10680                         btrfs_put_transaction(trans);
10681
10682                 if (ret) {
10683                         up_read(&fs_info->commit_root_sem);
10684                         mutex_unlock(&fs_info->chunk_mutex);
10685                         if (ret == -ENOSPC)
10686                                 ret = 0;
10687                         break;
10688                 }
10689
10690                 ret = btrfs_issue_discard(device->bdev, start, len, &bytes);
10691                 up_read(&fs_info->commit_root_sem);
10692                 mutex_unlock(&fs_info->chunk_mutex);
10693
10694                 if (ret)
10695                         break;
10696
10697                 start += len;
10698                 *trimmed += bytes;
10699
10700                 if (fatal_signal_pending(current)) {
10701                         ret = -ERESTARTSYS;
10702                         break;
10703                 }
10704
10705                 cond_resched();
10706         }
10707
10708         return ret;
10709 }
10710
10711 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
10712 {
10713         struct btrfs_fs_info *fs_info = root->fs_info;
10714         struct btrfs_block_group_cache *cache = NULL;
10715         struct btrfs_device *device;
10716         struct list_head *devices;
10717         u64 group_trimmed;
10718         u64 start;
10719         u64 end;
10720         u64 trimmed = 0;
10721         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
10722         int ret = 0;
10723
10724         /*
10725          * try to trim all FS space, our block group may start from non-zero.
10726          */
10727         if (range->len == total_bytes)
10728                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
10729         else
10730                 cache = btrfs_lookup_block_group(fs_info, range->start);
10731
10732         while (cache) {
10733                 if (cache->key.objectid >= (range->start + range->len)) {
10734                         btrfs_put_block_group(cache);
10735                         break;
10736                 }
10737
10738                 start = max(range->start, cache->key.objectid);
10739                 end = min(range->start + range->len,
10740                                 cache->key.objectid + cache->key.offset);
10741
10742                 if (end - start >= range->minlen) {
10743                         if (!block_group_cache_done(cache)) {
10744                                 ret = cache_block_group(cache, 0);
10745                                 if (ret) {
10746                                         btrfs_put_block_group(cache);
10747                                         break;
10748                                 }
10749                                 ret = wait_block_group_cache_done(cache);
10750                                 if (ret) {
10751                                         btrfs_put_block_group(cache);
10752                                         break;
10753                                 }
10754                         }
10755                         ret = btrfs_trim_block_group(cache,
10756                                                      &group_trimmed,
10757                                                      start,
10758                                                      end,
10759                                                      range->minlen);
10760
10761                         trimmed += group_trimmed;
10762                         if (ret) {
10763                                 btrfs_put_block_group(cache);
10764                                 break;
10765                         }
10766                 }
10767
10768                 cache = next_block_group(fs_info->tree_root, cache);
10769         }
10770
10771         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
10772         devices = &root->fs_info->fs_devices->alloc_list;
10773         list_for_each_entry(device, devices, dev_alloc_list) {
10774                 ret = btrfs_trim_free_extents(device, range->minlen,
10775                                               &group_trimmed);
10776                 if (ret)
10777                         break;
10778
10779                 trimmed += group_trimmed;
10780         }
10781         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
10782
10783         range->len = trimmed;
10784         return ret;
10785 }
10786
10787 /*
10788  * btrfs_{start,end}_write_no_snapshoting() are similar to
10789  * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
10790  * data into the page cache through nocow before the subvolume is snapshoted,
10791  * but flush the data into disk after the snapshot creation, or to prevent
10792  * operations while snapshoting is ongoing and that cause the snapshot to be
10793  * inconsistent (writes followed by expanding truncates for example).
10794  */
10795 void btrfs_end_write_no_snapshoting(struct btrfs_root *root)
10796 {
10797         percpu_counter_dec(&root->subv_writers->counter);
10798         /*
10799          * Make sure counter is updated before we wake up waiters.
10800          */
10801         smp_mb();
10802         if (waitqueue_active(&root->subv_writers->wait))
10803                 wake_up(&root->subv_writers->wait);
10804 }
10805
10806 int btrfs_start_write_no_snapshoting(struct btrfs_root *root)
10807 {
10808         if (atomic_read(&root->will_be_snapshoted))
10809                 return 0;
10810
10811         percpu_counter_inc(&root->subv_writers->counter);
10812         /*
10813          * Make sure counter is updated before we check for snapshot creation.
10814          */
10815         smp_mb();
10816         if (atomic_read(&root->will_be_snapshoted)) {
10817                 btrfs_end_write_no_snapshoting(root);
10818                 return 0;
10819         }
10820         return 1;
10821 }
10822
10823 static int wait_snapshoting_atomic_t(atomic_t *a)
10824 {
10825         schedule();
10826         return 0;
10827 }
10828
10829 void btrfs_wait_for_snapshot_creation(struct btrfs_root *root)
10830 {
10831         while (true) {
10832                 int ret;
10833
10834                 ret = btrfs_start_write_no_snapshoting(root);
10835                 if (ret)
10836                         break;
10837                 wait_on_atomic_t(&root->will_be_snapshoted,
10838                                  wait_snapshoting_atomic_t,
10839                                  TASK_UNINTERRUPTIBLE);
10840         }
10841 }