fs/btrfs/free-space-cache.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2008 Red Hat.  All rights reserved.
   4  */
   5
   6 #include <linux/pagemap.h>
   7 #include <linux/sched.h>
   8 #include <linux/sched/signal.h>
   9 #include <linux/slab.h>
  10 #include <linux/math64.h>
  11 #include <linux/ratelimit.h>
  12 #include <linux/error-injection.h>
  13 #include <linux/sched/mm.h>
  14 #include "ctree.h"
  15 #include "fs.h"
  16 #include "messages.h"
  17 #include "misc.h"
  18 #include "free-space-cache.h"
  19 #include "transaction.h"
  20 #include "disk-io.h"
  21 #include "extent_io.h"
  22 #include "space-info.h"
  23 #include "block-group.h"
  24 #include "discard.h"
  25 #include "subpage.h"
  26 #include "inode-item.h"
  27 #include "accessors.h"
  28 #include "file-item.h"
  29 #include "file.h"
  30 #include "super.h"
  31
  32 #define BITS_PER_BITMAP         (PAGE_SIZE * 8UL)
  33 #define MAX_CACHE_BYTES_PER_GIG SZ_64K
  34 #define FORCE_EXTENT_THRESHOLD  SZ_1M
  35
  36 static struct kmem_cache *btrfs_free_space_cachep;
  37 static struct kmem_cache *btrfs_free_space_bitmap_cachep;
  38
  39 struct btrfs_trim_range {
  40         u64 start;
  41         u64 bytes;
  42         struct list_head list;
  43 };
  44
  45 static int link_free_space(struct btrfs_free_space_ctl *ctl,
  46                            struct btrfs_free_space *info);
  47 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
  48                               struct btrfs_free_space *info, bool update_stat);
  49 static int search_bitmap(struct btrfs_free_space_ctl *ctl,
  50                          struct btrfs_free_space *bitmap_info, u64 *offset,
  51                          u64 *bytes, bool for_alloc);
  52 static void free_bitmap(struct btrfs_free_space_ctl *ctl,
  53                         struct btrfs_free_space *bitmap_info);
  54 static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
  55                               struct btrfs_free_space *info, u64 offset,
  56                               u64 bytes, bool update_stats);
  57
  58 static void btrfs_crc32c_final(u32 crc, u8 *result)
  59 {
  60         put_unaligned_le32(~crc, result);
  61 }
  62
  63 static void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
  64 {
  65         struct btrfs_free_space *info;
  66         struct rb_node *node;
  67
  68         while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
  69                 info = rb_entry(node, struct btrfs_free_space, offset_index);
  70                 if (!info->bitmap) {
  71                         unlink_free_space(ctl, info, true);
  72                         kmem_cache_free(btrfs_free_space_cachep, info);
  73                 } else {
  74                         free_bitmap(ctl, info);
  75                 }
  76
  77                 cond_resched_lock(&ctl->tree_lock);
  78         }
  79 }
  80
  81 static struct inode *__lookup_free_space_inode(struct btrfs_root *root,
  82                                                struct btrfs_path *path,
  83                                                u64 offset)
  84 {
  85         struct btrfs_key key;
  86         struct btrfs_key location;
  87         struct btrfs_disk_key disk_key;
  88         struct btrfs_free_space_header *header;
  89         struct extent_buffer *leaf;
  90         struct inode *inode = NULL;
  91         unsigned nofs_flag;
  92         int ret;
  93
  94         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
  95         key.offset = offset;
  96         key.type = 0;
  97
  98         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
  99         if (ret < 0)
 100                 return ERR_PTR(ret);
 101         if (ret > 0) {
 102                 btrfs_release_path(path);
 103                 return ERR_PTR(-ENOENT);
 104         }
 105
 106         leaf = path->nodes[0];
 107         header = btrfs_item_ptr(leaf, path->slots[0],
 108                                 struct btrfs_free_space_header);
 109         btrfs_free_space_key(leaf, header, &disk_key);
 110         btrfs_disk_key_to_cpu(&location, &disk_key);
 111         btrfs_release_path(path);
 112
 113         /*
 114          * We are often under a trans handle at this point, so we need to make
 115          * sure NOFS is set to keep us from deadlocking.
 116          */
 117         nofs_flag = memalloc_nofs_save();
 118         inode = btrfs_iget_path(location.objectid, root, path);
 119         btrfs_release_path(path);
 120         memalloc_nofs_restore(nofs_flag);
 121         if (IS_ERR(inode))
 122                 return inode;
 123
 124         mapping_set_gfp_mask(inode->i_mapping,
 125                         mapping_gfp_constraint(inode->i_mapping,
 126                         ~(__GFP_FS | __GFP_HIGHMEM)));
 127
 128         return inode;
 129 }
 130
 131 struct inode *lookup_free_space_inode(struct btrfs_block_group *block_group,
 132                 struct btrfs_path *path)
 133 {
 134         struct btrfs_fs_info *fs_info = block_group->fs_info;
 135         struct inode *inode = NULL;
 136         u32 flags = BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
 137
 138         spin_lock(&block_group->lock);
 139         if (block_group->inode)
 140                 inode = igrab(&block_group->inode->vfs_inode);
 141         spin_unlock(&block_group->lock);
 142         if (inode)
 143                 return inode;
 144
 145         inode = __lookup_free_space_inode(fs_info->tree_root, path,
 146                                           block_group->start);
 147         if (IS_ERR(inode))
 148                 return inode;
 149
 150         spin_lock(&block_group->lock);
 151         if (!((BTRFS_I(inode)->flags & flags) == flags)) {
 152                 btrfs_info(fs_info, "Old style space inode found, converting.");
 153                 BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM |
 154                         BTRFS_INODE_NODATACOW;
 155                 block_group->disk_cache_state = BTRFS_DC_CLEAR;
 156         }
 157
 158         if (!test_and_set_bit(BLOCK_GROUP_FLAG_IREF, &block_group->runtime_flags))
 159                 block_group->inode = BTRFS_I(igrab(inode));
 160         spin_unlock(&block_group->lock);
 161
 162         return inode;
 163 }
 164
 165 static int __create_free_space_inode(struct btrfs_root *root,
 166                                      struct btrfs_trans_handle *trans,
 167                                      struct btrfs_path *path,
 168                                      u64 ino, u64 offset)
 169 {
 170         struct btrfs_key key;
 171         struct btrfs_disk_key disk_key;
 172         struct btrfs_free_space_header *header;
 173         struct btrfs_inode_item *inode_item;
 174         struct extent_buffer *leaf;
 175         /* We inline CRCs for the free disk space cache */
 176         const u64 flags = BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC |
 177                           BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
 178         int ret;
 179
 180         ret = btrfs_insert_empty_inode(trans, root, path, ino);
 181         if (ret)
 182                 return ret;
 183
 184         leaf = path->nodes[0];
 185         inode_item = btrfs_item_ptr(leaf, path->slots[0],
 186                                     struct btrfs_inode_item);
 187         btrfs_item_key(leaf, &disk_key, path->slots[0]);
 188         memzero_extent_buffer(leaf, (unsigned long)inode_item,
 189                              sizeof(*inode_item));
 190         btrfs_set_inode_generation(leaf, inode_item, trans->transid);
 191         btrfs_set_inode_size(leaf, inode_item, 0);
 192         btrfs_set_inode_nbytes(leaf, inode_item, 0);
 193         btrfs_set_inode_uid(leaf, inode_item, 0);
 194         btrfs_set_inode_gid(leaf, inode_item, 0);
 195         btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600);
 196         btrfs_set_inode_flags(leaf, inode_item, flags);
 197         btrfs_set_inode_nlink(leaf, inode_item, 1);
 198         btrfs_set_inode_transid(leaf, inode_item, trans->transid);
 199         btrfs_set_inode_block_group(leaf, inode_item, offset);
 200         btrfs_mark_buffer_dirty(trans, leaf);
 201         btrfs_release_path(path);
 202
 203         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 204         key.offset = offset;
 205         key.type = 0;
 206         ret = btrfs_insert_empty_item(trans, root, path, &key,
 207                                       sizeof(struct btrfs_free_space_header));
 208         if (ret < 0) {
 209                 btrfs_release_path(path);
 210                 return ret;
 211         }
 212
 213         leaf = path->nodes[0];
 214         header = btrfs_item_ptr(leaf, path->slots[0],
 215                                 struct btrfs_free_space_header);
 216         memzero_extent_buffer(leaf, (unsigned long)header, sizeof(*header));
 217         btrfs_set_free_space_key(leaf, header, &disk_key);
 218         btrfs_mark_buffer_dirty(trans, leaf);
 219         btrfs_release_path(path);
 220
 221         return 0;
 222 }
 223
 224 int create_free_space_inode(struct btrfs_trans_handle *trans,
 225                             struct btrfs_block_group *block_group,
 226                             struct btrfs_path *path)
 227 {
 228         int ret;
 229         u64 ino;
 230
 231         ret = btrfs_get_free_objectid(trans->fs_info->tree_root, &ino);
 232         if (ret < 0)
 233                 return ret;
 234
 235         return __create_free_space_inode(trans->fs_info->tree_root, trans, path,
 236                                          ino, block_group->start);
 237 }
 238
 239 /*
 240  * inode is an optional sink: if it is NULL, btrfs_remove_free_space_inode
 241  * handles lookup, otherwise it takes ownership and iputs the inode.
 242  * Don't reuse an inode pointer after passing it into this function.
 243  */
 244 int btrfs_remove_free_space_inode(struct btrfs_trans_handle *trans,
 245                                   struct inode *inode,
 246                                   struct btrfs_block_group *block_group)
 247 {
 248         struct btrfs_path *path;
 249         struct btrfs_key key;
 250         int ret = 0;
 251
 252         path = btrfs_alloc_path();
 253         if (!path)
 254                 return -ENOMEM;
 255
 256         if (!inode)
 257                 inode = lookup_free_space_inode(block_group, path);
 258         if (IS_ERR(inode)) {
 259                 if (PTR_ERR(inode) != -ENOENT)
 260                         ret = PTR_ERR(inode);
 261                 goto out;
 262         }
 263         ret = btrfs_orphan_add(trans, BTRFS_I(inode));
 264         if (ret) {
 265                 btrfs_add_delayed_iput(BTRFS_I(inode));
 266                 goto out;
 267         }
 268         clear_nlink(inode);
 269         /* One for the block groups ref */
 270         spin_lock(&block_group->lock);
 271         if (test_and_clear_bit(BLOCK_GROUP_FLAG_IREF, &block_group->runtime_flags)) {
 272                 block_group->inode = NULL;
 273                 spin_unlock(&block_group->lock);
 274                 iput(inode);
 275         } else {
 276                 spin_unlock(&block_group->lock);
 277         }
 278         /* One for the lookup ref */
 279         btrfs_add_delayed_iput(BTRFS_I(inode));
 280
 281         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 282         key.type = 0;
 283         key.offset = block_group->start;
 284         ret = btrfs_search_slot(trans, trans->fs_info->tree_root, &key, path,
 285                                 -1, 1);
 286         if (ret) {
 287                 if (ret > 0)
 288                         ret = 0;
 289                 goto out;
 290         }
 291         ret = btrfs_del_item(trans, trans->fs_info->tree_root, path);
 292 out:
 293         btrfs_free_path(path);
 294         return ret;
 295 }
 296
 297 int btrfs_truncate_free_space_cache(struct btrfs_trans_handle *trans,
 298                                     struct btrfs_block_group *block_group,
 299                                     struct inode *vfs_inode)
 300 {
 301         struct btrfs_truncate_control control = {
 302                 .inode = BTRFS_I(vfs_inode),
 303                 .new_size = 0,
 304                 .ino = btrfs_ino(BTRFS_I(vfs_inode)),
 305                 .min_type = BTRFS_EXTENT_DATA_KEY,
 306                 .clear_extent_range = true,
 307         };
 308         struct btrfs_inode *inode = BTRFS_I(vfs_inode);
 309         struct btrfs_root *root = inode->root;
 310         struct extent_state *cached_state = NULL;
 311         int ret = 0;
 312         bool locked = false;
 313
 314         if (block_group) {
 315                 struct btrfs_path *path = btrfs_alloc_path();
 316
 317                 if (!path) {
 318                         ret = -ENOMEM;
 319                         goto fail;
 320                 }
 321                 locked = true;
 322                 mutex_lock(&trans->transaction->cache_write_mutex);
 323                 if (!list_empty(&block_group->io_list)) {
 324                         list_del_init(&block_group->io_list);
 325
 326                         btrfs_wait_cache_io(trans, block_group, path);
 327                         btrfs_put_block_group(block_group);
 328                 }
 329
 330                 /*
 331                  * now that we've truncated the cache away, its no longer
 332                  * setup or written
 333                  */
 334                 spin_lock(&block_group->lock);
 335                 block_group->disk_cache_state = BTRFS_DC_CLEAR;
 336                 spin_unlock(&block_group->lock);
 337                 btrfs_free_path(path);
 338         }
 339
 340         btrfs_i_size_write(inode, 0);
 341         truncate_pagecache(vfs_inode, 0);
 342
 343         lock_extent(&inode->io_tree, 0, (u64)-1, &cached_state);
 344         btrfs_drop_extent_map_range(inode, 0, (u64)-1, false);
 345
 346         /*
 347          * We skip the throttling logic for free space cache inodes, so we don't
 348          * need to check for -EAGAIN.
 349          */
 350         ret = btrfs_truncate_inode_items(trans, root, &control);
 351
 352         inode_sub_bytes(&inode->vfs_inode, control.sub_bytes);
 353         btrfs_inode_safe_disk_i_size_write(inode, control.last_size);
 354
 355         unlock_extent(&inode->io_tree, 0, (u64)-1, &cached_state);
 356         if (ret)
 357                 goto fail;
 358
 359         ret = btrfs_update_inode(trans, inode);
 360
 361 fail:
 362         if (locked)
 363                 mutex_unlock(&trans->transaction->cache_write_mutex);
 364         if (ret)
 365                 btrfs_abort_transaction(trans, ret);
 366
 367         return ret;
 368 }
 369
 370 static void readahead_cache(struct inode *inode)
 371 {
 372         struct file_ra_state ra;
 373         unsigned long last_index;
 374
 375         file_ra_state_init(&ra, inode->i_mapping);
 376         last_index = (i_size_read(inode) - 1) >> PAGE_SHIFT;
 377
 378         page_cache_sync_readahead(inode->i_mapping, &ra, NULL, 0, last_index);
 379 }
 380
 381 static int io_ctl_init(struct btrfs_io_ctl *io_ctl, struct inode *inode,
 382                        int write)
 383 {
 384         int num_pages;
 385
 386         num_pages = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
 387
 388         /* Make sure we can fit our crcs and generation into the first page */
 389         if (write && (num_pages * sizeof(u32) + sizeof(u64)) > PAGE_SIZE)
 390                 return -ENOSPC;
 391
 392         memset(io_ctl, 0, sizeof(struct btrfs_io_ctl));
 393
 394         io_ctl->pages = kcalloc(num_pages, sizeof(struct page *), GFP_NOFS);
 395         if (!io_ctl->pages)
 396                 return -ENOMEM;
 397
 398         io_ctl->num_pages = num_pages;
 399         io_ctl->fs_info = inode_to_fs_info(inode);
 400         io_ctl->inode = inode;
 401
 402         return 0;
 403 }
 404 ALLOW_ERROR_INJECTION(io_ctl_init, ERRNO);
 405
 406 static void io_ctl_free(struct btrfs_io_ctl *io_ctl)
 407 {
 408         kfree(io_ctl->pages);
 409         io_ctl->pages = NULL;
 410 }
 411
 412 static void io_ctl_unmap_page(struct btrfs_io_ctl *io_ctl)
 413 {
 414         if (io_ctl->cur) {
 415                 io_ctl->cur = NULL;
 416                 io_ctl->orig = NULL;
 417         }
 418 }
 419
 420 static void io_ctl_map_page(struct btrfs_io_ctl *io_ctl, int clear)
 421 {
 422         ASSERT(io_ctl->index < io_ctl->num_pages);
 423         io_ctl->page = io_ctl->pages[io_ctl->index++];
 424         io_ctl->cur = page_address(io_ctl->page);
 425         io_ctl->orig = io_ctl->cur;
 426         io_ctl->size = PAGE_SIZE;
 427         if (clear)
 428                 clear_page(io_ctl->cur);
 429 }
 430
 431 static void io_ctl_drop_pages(struct btrfs_io_ctl *io_ctl)
 432 {
 433         int i;
 434
 435         io_ctl_unmap_page(io_ctl);
 436
 437         for (i = 0; i < io_ctl->num_pages; i++) {
 438                 if (io_ctl->pages[i]) {
 439                         btrfs_folio_clear_checked(io_ctl->fs_info,
 440                                         page_folio(io_ctl->pages[i]),
 441                                         page_offset(io_ctl->pages[i]),
 442                                         PAGE_SIZE);
 443                         unlock_page(io_ctl->pages[i]);
 444                         put_page(io_ctl->pages[i]);
 445                 }
 446         }
 447 }
 448
 449 static int io_ctl_prepare_pages(struct btrfs_io_ctl *io_ctl, bool uptodate)
 450 {
 451         struct page *page;
 452         struct inode *inode = io_ctl->inode;
 453         gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
 454         int i;
 455
 456         for (i = 0; i < io_ctl->num_pages; i++) {
 457                 int ret;
 458
 459                 page = find_or_create_page(inode->i_mapping, i, mask);
 460                 if (!page) {
 461                         io_ctl_drop_pages(io_ctl);
 462                         return -ENOMEM;
 463                 }
 464
 465                 ret = set_page_extent_mapped(page);
 466                 if (ret < 0) {
 467                         unlock_page(page);
 468                         put_page(page);
 469                         io_ctl_drop_pages(io_ctl);
 470                         return ret;
 471                 }
 472
 473                 io_ctl->pages[i] = page;
 474                 if (uptodate && !PageUptodate(page)) {
 475                         btrfs_read_folio(NULL, page_folio(page));
 476                         lock_page(page);
 477                         if (page->mapping != inode->i_mapping) {
 478                                 btrfs_err(BTRFS_I(inode)->root->fs_info,
 479                                           "free space cache page truncated");
 480                                 io_ctl_drop_pages(io_ctl);
 481                                 return -EIO;
 482                         }
 483                         if (!PageUptodate(page)) {
 484                                 btrfs_err(BTRFS_I(inode)->root->fs_info,
 485                                            "error reading free space cache");
 486                                 io_ctl_drop_pages(io_ctl);
 487                                 return -EIO;
 488                         }
 489                 }
 490         }
 491
 492         for (i = 0; i < io_ctl->num_pages; i++)
 493                 clear_page_dirty_for_io(io_ctl->pages[i]);
 494
 495         return 0;
 496 }
 497
 498 static void io_ctl_set_generation(struct btrfs_io_ctl *io_ctl, u64 generation)
 499 {
 500         io_ctl_map_page(io_ctl, 1);
 501
 502         /*
 503          * Skip the csum areas.  If we don't check crcs then we just have a
 504          * 64bit chunk at the front of the first page.
 505          */
 506         io_ctl->cur += (sizeof(u32) * io_ctl->num_pages);
 507         io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
 508
 509         put_unaligned_le64(generation, io_ctl->cur);
 510         io_ctl->cur += sizeof(u64);
 511 }
 512
 513 static int io_ctl_check_generation(struct btrfs_io_ctl *io_ctl, u64 generation)
 514 {
 515         u64 cache_gen;
 516
 517         /*
 518          * Skip the crc area.  If we don't check crcs then we just have a 64bit
 519          * chunk at the front of the first page.
 520          */
 521         io_ctl->cur += sizeof(u32) * io_ctl->num_pages;
 522         io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
 523
 524         cache_gen = get_unaligned_le64(io_ctl->cur);
 525         if (cache_gen != generation) {
 526                 btrfs_err_rl(io_ctl->fs_info,
 527                         "space cache generation (%llu) does not match inode (%llu)",
 528                                 cache_gen, generation);
 529                 io_ctl_unmap_page(io_ctl);
 530                 return -EIO;
 531         }
 532         io_ctl->cur += sizeof(u64);
 533         return 0;
 534 }
 535
 536 static void io_ctl_set_crc(struct btrfs_io_ctl *io_ctl, int index)
 537 {
 538         u32 *tmp;
 539         u32 crc = ~(u32)0;
 540         unsigned offset = 0;
 541
 542         if (index == 0)
 543                 offset = sizeof(u32) * io_ctl->num_pages;
 544
 545         crc = crc32c(crc, io_ctl->orig + offset, PAGE_SIZE - offset);
 546         btrfs_crc32c_final(crc, (u8 *)&crc);
 547         io_ctl_unmap_page(io_ctl);
 548         tmp = page_address(io_ctl->pages[0]);
 549         tmp += index;
 550         *tmp = crc;
 551 }
 552
 553 static int io_ctl_check_crc(struct btrfs_io_ctl *io_ctl, int index)
 554 {
 555         u32 *tmp, val;
 556         u32 crc = ~(u32)0;
 557         unsigned offset = 0;
 558
 559         if (index == 0)
 560                 offset = sizeof(u32) * io_ctl->num_pages;
 561
 562         tmp = page_address(io_ctl->pages[0]);
 563         tmp += index;
 564         val = *tmp;
 565
 566         io_ctl_map_page(io_ctl, 0);
 567         crc = crc32c(crc, io_ctl->orig + offset, PAGE_SIZE - offset);
 568         btrfs_crc32c_final(crc, (u8 *)&crc);
 569         if (val != crc) {
 570                 btrfs_err_rl(io_ctl->fs_info,
 571                         "csum mismatch on free space cache");
 572                 io_ctl_unmap_page(io_ctl);
 573                 return -EIO;
 574         }
 575
 576         return 0;
 577 }
 578
 579 static int io_ctl_add_entry(struct btrfs_io_ctl *io_ctl, u64 offset, u64 bytes,
 580                             void *bitmap)
 581 {
 582         struct btrfs_free_space_entry *entry;
 583
 584         if (!io_ctl->cur)
 585                 return -ENOSPC;
 586
 587         entry = io_ctl->cur;
 588         put_unaligned_le64(offset, &entry->offset);
 589         put_unaligned_le64(bytes, &entry->bytes);
 590         entry->type = (bitmap) ? BTRFS_FREE_SPACE_BITMAP :
 591                 BTRFS_FREE_SPACE_EXTENT;
 592         io_ctl->cur += sizeof(struct btrfs_free_space_entry);
 593         io_ctl->size -= sizeof(struct btrfs_free_space_entry);
 594
 595         if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
 596                 return 0;
 597
 598         io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 599
 600         /* No more pages to map */
 601         if (io_ctl->index >= io_ctl->num_pages)
 602                 return 0;
 603
 604         /* map the next page */
 605         io_ctl_map_page(io_ctl, 1);
 606         return 0;
 607 }
 608
 609 static int io_ctl_add_bitmap(struct btrfs_io_ctl *io_ctl, void *bitmap)
 610 {
 611         if (!io_ctl->cur)
 612                 return -ENOSPC;
 613
 614         /*
 615          * If we aren't at the start of the current page, unmap this one and
 616          * map the next one if there is any left.
 617          */
 618         if (io_ctl->cur != io_ctl->orig) {
 619                 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 620                 if (io_ctl->index >= io_ctl->num_pages)
 621                         return -ENOSPC;
 622                 io_ctl_map_page(io_ctl, 0);
 623         }
 624
 625         copy_page(io_ctl->cur, bitmap);
 626         io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 627         if (io_ctl->index < io_ctl->num_pages)
 628                 io_ctl_map_page(io_ctl, 0);
 629         return 0;
 630 }
 631
 632 static void io_ctl_zero_remaining_pages(struct btrfs_io_ctl *io_ctl)
 633 {
 634         /*
 635          * If we're not on the boundary we know we've modified the page and we
 636          * need to crc the page.
 637          */
 638         if (io_ctl->cur != io_ctl->orig)
 639                 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 640         else
 641                 io_ctl_unmap_page(io_ctl);
 642
 643         while (io_ctl->index < io_ctl->num_pages) {
 644                 io_ctl_map_page(io_ctl, 1);
 645                 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 646         }
 647 }
 648
 649 static int io_ctl_read_entry(struct btrfs_io_ctl *io_ctl,
 650                             struct btrfs_free_space *entry, u8 *type)
 651 {
 652         struct btrfs_free_space_entry *e;
 653         int ret;
 654
 655         if (!io_ctl->cur) {
 656                 ret = io_ctl_check_crc(io_ctl, io_ctl->index);
 657                 if (ret)
 658                         return ret;
 659         }
 660
 661         e = io_ctl->cur;
 662         entry->offset = get_unaligned_le64(&e->offset);
 663         entry->bytes = get_unaligned_le64(&e->bytes);
 664         *type = e->type;
 665         io_ctl->cur += sizeof(struct btrfs_free_space_entry);
 666         io_ctl->size -= sizeof(struct btrfs_free_space_entry);
 667
 668         if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
 669                 return 0;
 670
 671         io_ctl_unmap_page(io_ctl);
 672
 673         return 0;
 674 }
 675
 676 static int io_ctl_read_bitmap(struct btrfs_io_ctl *io_ctl,
 677                               struct btrfs_free_space *entry)
 678 {
 679         int ret;
 680
 681         ret = io_ctl_check_crc(io_ctl, io_ctl->index);
 682         if (ret)
 683                 return ret;
 684
 685         copy_page(entry->bitmap, io_ctl->cur);
 686         io_ctl_unmap_page(io_ctl);
 687
 688         return 0;
 689 }
 690
 691 static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
 692 {
 693         struct btrfs_block_group *block_group = ctl->block_group;
 694         u64 max_bytes;
 695         u64 bitmap_bytes;
 696         u64 extent_bytes;
 697         u64 size = block_group->length;
 698         u64 bytes_per_bg = BITS_PER_BITMAP * ctl->unit;
 699         u64 max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg);
 700
 701         max_bitmaps = max_t(u64, max_bitmaps, 1);
 702
 703         if (ctl->total_bitmaps > max_bitmaps)
 704                 btrfs_err(block_group->fs_info,
 705 "invalid free space control: bg start=%llu len=%llu total_bitmaps=%u unit=%u max_bitmaps=%llu bytes_per_bg=%llu",
 706                           block_group->start, block_group->length,
 707                           ctl->total_bitmaps, ctl->unit, max_bitmaps,
 708                           bytes_per_bg);
 709         ASSERT(ctl->total_bitmaps <= max_bitmaps);
 710
 711         /*
 712          * We are trying to keep the total amount of memory used per 1GiB of
 713          * space to be MAX_CACHE_BYTES_PER_GIG.  However, with a reclamation
 714          * mechanism of pulling extents >= FORCE_EXTENT_THRESHOLD out of
 715          * bitmaps, we may end up using more memory than this.
 716          */
 717         if (size < SZ_1G)
 718                 max_bytes = MAX_CACHE_BYTES_PER_GIG;
 719         else
 720                 max_bytes = MAX_CACHE_BYTES_PER_GIG * div_u64(size, SZ_1G);
 721
 722         bitmap_bytes = ctl->total_bitmaps * ctl->unit;
 723
 724         /*
 725          * we want the extent entry threshold to always be at most 1/2 the max
 726          * bytes we can have, or whatever is less than that.
 727          */
 728         extent_bytes = max_bytes - bitmap_bytes;
 729         extent_bytes = min_t(u64, extent_bytes, max_bytes >> 1);
 730
 731         ctl->extents_thresh =
 732                 div_u64(extent_bytes, sizeof(struct btrfs_free_space));
 733 }
 734
 735 static int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
 736                                    struct btrfs_free_space_ctl *ctl,
 737                                    struct btrfs_path *path, u64 offset)
 738 {
 739         struct btrfs_fs_info *fs_info = root->fs_info;
 740         struct btrfs_free_space_header *header;
 741         struct extent_buffer *leaf;
 742         struct btrfs_io_ctl io_ctl;
 743         struct btrfs_key key;
 744         struct btrfs_free_space *e, *n;
 745         LIST_HEAD(bitmaps);
 746         u64 num_entries;
 747         u64 num_bitmaps;
 748         u64 generation;
 749         u8 type;
 750         int ret = 0;
 751
 752         /* Nothing in the space cache, goodbye */
 753         if (!i_size_read(inode))
 754                 return 0;
 755
 756         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 757         key.offset = offset;
 758         key.type = 0;
 759
 760         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 761         if (ret < 0)
 762                 return 0;
 763         else if (ret > 0) {
 764                 btrfs_release_path(path);
 765                 return 0;
 766         }
 767
 768         ret = -1;
 769
 770         leaf = path->nodes[0];
 771         header = btrfs_item_ptr(leaf, path->slots[0],
 772                                 struct btrfs_free_space_header);
 773         num_entries = btrfs_free_space_entries(leaf, header);
 774         num_bitmaps = btrfs_free_space_bitmaps(leaf, header);
 775         generation = btrfs_free_space_generation(leaf, header);
 776         btrfs_release_path(path);
 777
 778         if (!BTRFS_I(inode)->generation) {
 779                 btrfs_info(fs_info,
 780                            "the free space cache file (%llu) is invalid, skip it",
 781                            offset);
 782                 return 0;
 783         }
 784
 785         if (BTRFS_I(inode)->generation != generation) {
 786                 btrfs_err(fs_info,
 787                           "free space inode generation (%llu) did not match free space cache generation (%llu)",
 788                           BTRFS_I(inode)->generation, generation);
 789                 return 0;
 790         }
 791
 792         if (!num_entries)
 793                 return 0;
 794
 795         ret = io_ctl_init(&io_ctl, inode, 0);
 796         if (ret)
 797                 return ret;
 798
 799         readahead_cache(inode);
 800
 801         ret = io_ctl_prepare_pages(&io_ctl, true);
 802         if (ret)
 803                 goto out;
 804
 805         ret = io_ctl_check_crc(&io_ctl, 0);
 806         if (ret)
 807                 goto free_cache;
 808
 809         ret = io_ctl_check_generation(&io_ctl, generation);
 810         if (ret)
 811                 goto free_cache;
 812
 813         while (num_entries) {
 814                 e = kmem_cache_zalloc(btrfs_free_space_cachep,
 815                                       GFP_NOFS);
 816                 if (!e) {
 817                         ret = -ENOMEM;
 818                         goto free_cache;
 819                 }
 820
 821                 ret = io_ctl_read_entry(&io_ctl, e, &type);
 822                 if (ret) {
 823                         kmem_cache_free(btrfs_free_space_cachep, e);
 824                         goto free_cache;
 825                 }
 826
 827                 if (!e->bytes) {
 828                         ret = -1;
 829                         kmem_cache_free(btrfs_free_space_cachep, e);
 830                         goto free_cache;
 831                 }
 832
 833                 if (type == BTRFS_FREE_SPACE_EXTENT) {
 834                         spin_lock(&ctl->tree_lock);
 835                         ret = link_free_space(ctl, e);
 836                         spin_unlock(&ctl->tree_lock);
 837                         if (ret) {
 838                                 btrfs_err(fs_info,
 839                                         "Duplicate entries in free space cache, dumping");
 840                                 kmem_cache_free(btrfs_free_space_cachep, e);
 841                                 goto free_cache;
 842                         }
 843                 } else {
 844                         ASSERT(num_bitmaps);
 845                         num_bitmaps--;
 846                         e->bitmap = kmem_cache_zalloc(
 847                                         btrfs_free_space_bitmap_cachep, GFP_NOFS);
 848                         if (!e->bitmap) {
 849                                 ret = -ENOMEM;
 850                                 kmem_cache_free(
 851                                         btrfs_free_space_cachep, e);
 852                                 goto free_cache;
 853                         }
 854                         spin_lock(&ctl->tree_lock);
 855                         ret = link_free_space(ctl, e);
 856                         if (ret) {
 857                                 spin_unlock(&ctl->tree_lock);
 858                                 btrfs_err(fs_info,
 859                                         "Duplicate entries in free space cache, dumping");
 860                                 kmem_cache_free(btrfs_free_space_bitmap_cachep, e->bitmap);
 861                                 kmem_cache_free(btrfs_free_space_cachep, e);
 862                                 goto free_cache;
 863                         }
 864                         ctl->total_bitmaps++;
 865                         recalculate_thresholds(ctl);
 866                         spin_unlock(&ctl->tree_lock);
 867                         list_add_tail(&e->list, &bitmaps);
 868                 }
 869
 870                 num_entries--;
 871         }
 872
 873         io_ctl_unmap_page(&io_ctl);
 874
 875         /*
 876          * We add the bitmaps at the end of the entries in order that
 877          * the bitmap entries are added to the cache.
 878          */
 879         list_for_each_entry_safe(e, n, &bitmaps, list) {
 880                 list_del_init(&e->list);
 881                 ret = io_ctl_read_bitmap(&io_ctl, e);
 882                 if (ret)
 883                         goto free_cache;
 884         }
 885
 886         io_ctl_drop_pages(&io_ctl);
 887         ret = 1;
 888 out:
 889         io_ctl_free(&io_ctl);
 890         return ret;
 891 free_cache:
 892         io_ctl_drop_pages(&io_ctl);
 893
 894         spin_lock(&ctl->tree_lock);
 895         __btrfs_remove_free_space_cache(ctl);
 896         spin_unlock(&ctl->tree_lock);
 897         goto out;
 898 }
 899
 900 static int copy_free_space_cache(struct btrfs_block_group *block_group,
 901                                  struct btrfs_free_space_ctl *ctl)
 902 {
 903         struct btrfs_free_space *info;
 904         struct rb_node *n;
 905         int ret = 0;
 906
 907         while (!ret && (n = rb_first(&ctl->free_space_offset)) != NULL) {
 908                 info = rb_entry(n, struct btrfs_free_space, offset_index);
 909                 if (!info->bitmap) {
 910                         const u64 offset = info->offset;
 911                         const u64 bytes = info->bytes;
 912
 913                         unlink_free_space(ctl, info, true);
 914                         spin_unlock(&ctl->tree_lock);
 915                         kmem_cache_free(btrfs_free_space_cachep, info);
 916                         ret = btrfs_add_free_space(block_group, offset, bytes);
 917                         spin_lock(&ctl->tree_lock);
 918                 } else {
 919                         u64 offset = info->offset;
 920                         u64 bytes = ctl->unit;
 921
 922                         ret = search_bitmap(ctl, info, &offset, &bytes, false);
 923                         if (ret == 0) {
 924                                 bitmap_clear_bits(ctl, info, offset, bytes, true);
 925                                 spin_unlock(&ctl->tree_lock);
 926                                 ret = btrfs_add_free_space(block_group, offset,
 927                                                            bytes);
 928                                 spin_lock(&ctl->tree_lock);
 929                         } else {
 930                                 free_bitmap(ctl, info);
 931                                 ret = 0;
 932                         }
 933                 }
 934                 cond_resched_lock(&ctl->tree_lock);
 935         }
 936         return ret;
 937 }
 938
 939 static struct lock_class_key btrfs_free_space_inode_key;
 940
 941 int load_free_space_cache(struct btrfs_block_group *block_group)
 942 {
 943         struct btrfs_fs_info *fs_info = block_group->fs_info;
 944         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
 945         struct btrfs_free_space_ctl tmp_ctl = {};
 946         struct inode *inode;
 947         struct btrfs_path *path;
 948         int ret = 0;
 949         bool matched;
 950         u64 used = block_group->used;
 951
 952         /*
 953          * Because we could potentially discard our loaded free space, we want
 954          * to load everything into a temporary structure first, and then if it's
 955          * valid copy it all into the actual free space ctl.
 956          */
 957         btrfs_init_free_space_ctl(block_group, &tmp_ctl);
 958
 959         /*
 960          * If this block group has been marked to be cleared for one reason or
 961          * another then we can't trust the on disk cache, so just return.
 962          */
 963         spin_lock(&block_group->lock);
 964         if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
 965                 spin_unlock(&block_group->lock);
 966                 return 0;
 967         }
 968         spin_unlock(&block_group->lock);
 969
 970         path = btrfs_alloc_path();
 971         if (!path)
 972                 return 0;
 973         path->search_commit_root = 1;
 974         path->skip_locking = 1;
 975
 976         /*
 977          * We must pass a path with search_commit_root set to btrfs_iget in
 978          * order to avoid a deadlock when allocating extents for the tree root.
 979          *
 980          * When we are COWing an extent buffer from the tree root, when looking
 981          * for a free extent, at extent-tree.c:find_free_extent(), we can find
 982          * block group without its free space cache loaded. When we find one
 983          * we must load its space cache which requires reading its free space
 984          * cache's inode item from the root tree. If this inode item is located
 985          * in the same leaf that we started COWing before, then we end up in
 986          * deadlock on the extent buffer (trying to read lock it when we
 987          * previously write locked it).
 988          *
 989          * It's safe to read the inode item using the commit root because
 990          * block groups, once loaded, stay in memory forever (until they are
 991          * removed) as well as their space caches once loaded. New block groups
 992          * once created get their ->cached field set to BTRFS_CACHE_FINISHED so
 993          * we will never try to read their inode item while the fs is mounted.
 994          */
 995         inode = lookup_free_space_inode(block_group, path);
 996         if (IS_ERR(inode)) {
 997                 btrfs_free_path(path);
 998                 return 0;
 999         }
1000
1001         /* We may have converted the inode and made the cache invalid. */
1002         spin_lock(&block_group->lock);
1003         if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
1004                 spin_unlock(&block_group->lock);
1005                 btrfs_free_path(path);
1006                 goto out;
1007         }
1008         spin_unlock(&block_group->lock);
1009
1010         /*
1011          * Reinitialize the class of struct inode's mapping->invalidate_lock for
1012          * free space inodes to prevent false positives related to locks for normal
1013          * inodes.
1014          */
1015         lockdep_set_class(&(&inode->i_data)->invalidate_lock,
1016                           &btrfs_free_space_inode_key);
1017
1018         ret = __load_free_space_cache(fs_info->tree_root, inode, &tmp_ctl,
1019                                       path, block_group->start);
1020         btrfs_free_path(path);
1021         if (ret <= 0)
1022                 goto out;
1023
1024         matched = (tmp_ctl.free_space == (block_group->length - used -
1025                                           block_group->bytes_super));
1026
1027         if (matched) {
1028                 spin_lock(&tmp_ctl.tree_lock);
1029                 ret = copy_free_space_cache(block_group, &tmp_ctl);
1030                 spin_unlock(&tmp_ctl.tree_lock);
1031                 /*
1032                  * ret == 1 means we successfully loaded the free space cache,
1033                  * so we need to re-set it here.
1034                  */
1035                 if (ret == 0)
1036                         ret = 1;
1037         } else {
1038                 /*
1039                  * We need to call the _locked variant so we don't try to update
1040                  * the discard counters.
1041                  */
1042                 spin_lock(&tmp_ctl.tree_lock);
1043                 __btrfs_remove_free_space_cache(&tmp_ctl);
1044                 spin_unlock(&tmp_ctl.tree_lock);
1045                 btrfs_warn(fs_info,
1046                            "block group %llu has wrong amount of free space",
1047                            block_group->start);
1048                 ret = -1;
1049         }
1050 out:
1051         if (ret < 0) {
1052                 /* This cache is bogus, make sure it gets cleared */
1053                 spin_lock(&block_group->lock);
1054                 block_group->disk_cache_state = BTRFS_DC_CLEAR;
1055                 spin_unlock(&block_group->lock);
1056                 ret = 0;
1057
1058                 btrfs_warn(fs_info,
1059                            "failed to load free space cache for block group %llu, rebuilding it now",
1060                            block_group->start);
1061         }
1062
1063         spin_lock(&ctl->tree_lock);
1064         btrfs_discard_update_discardable(block_group);
1065         spin_unlock(&ctl->tree_lock);
1066         iput(inode);
1067         return ret;
1068 }
1069
1070 static noinline_for_stack
1071 int write_cache_extent_entries(struct btrfs_io_ctl *io_ctl,
1072                               struct btrfs_free_space_ctl *ctl,
1073                               struct btrfs_block_group *block_group,
1074                               int *entries, int *bitmaps,
1075                               struct list_head *bitmap_list)
1076 {
1077         int ret;
1078         struct btrfs_free_cluster *cluster = NULL;
1079         struct btrfs_free_cluster *cluster_locked = NULL;
1080         struct rb_node *node = rb_first(&ctl->free_space_offset);
1081         struct btrfs_trim_range *trim_entry;
1082
1083         /* Get the cluster for this block_group if it exists */
1084         if (block_group && !list_empty(&block_group->cluster_list)) {
1085                 cluster = list_entry(block_group->cluster_list.next,
1086                                      struct btrfs_free_cluster,
1087                                      block_group_list);
1088         }
1089
1090         if (!node && cluster) {
1091                 cluster_locked = cluster;
1092                 spin_lock(&cluster_locked->lock);
1093                 node = rb_first(&cluster->root);
1094                 cluster = NULL;
1095         }
1096
1097         /* Write out the extent entries */
1098         while (node) {
1099                 struct btrfs_free_space *e;
1100
1101                 e = rb_entry(node, struct btrfs_free_space, offset_index);
1102                 *entries += 1;
1103
1104                 ret = io_ctl_add_entry(io_ctl, e->offset, e->bytes,
1105                                        e->bitmap);
1106                 if (ret)
1107                         goto fail;
1108
1109                 if (e->bitmap) {
1110                         list_add_tail(&e->list, bitmap_list);
1111                         *bitmaps += 1;
1112                 }
1113                 node = rb_next(node);
1114                 if (!node && cluster) {
1115                         node = rb_first(&cluster->root);
1116                         cluster_locked = cluster;
1117                         spin_lock(&cluster_locked->lock);
1118                         cluster = NULL;
1119                 }
1120         }
1121         if (cluster_locked) {
1122                 spin_unlock(&cluster_locked->lock);
1123                 cluster_locked = NULL;
1124         }
1125
1126         /*
1127          * Make sure we don't miss any range that was removed from our rbtree
1128          * because trimming is running. Otherwise after a umount+mount (or crash
1129          * after committing the transaction) we would leak free space and get
1130          * an inconsistent free space cache report from fsck.
1131          */
1132         list_for_each_entry(trim_entry, &ctl->trimming_ranges, list) {
1133                 ret = io_ctl_add_entry(io_ctl, trim_entry->start,
1134                                        trim_entry->bytes, NULL);
1135                 if (ret)
1136                         goto fail;
1137                 *entries += 1;
1138         }
1139
1140         return 0;
1141 fail:
1142         if (cluster_locked)
1143                 spin_unlock(&cluster_locked->lock);
1144         return -ENOSPC;
1145 }
1146
1147 static noinline_for_stack int
1148 update_cache_item(struct btrfs_trans_handle *trans,
1149                   struct btrfs_root *root,
1150                   struct inode *inode,
1151                   struct btrfs_path *path, u64 offset,
1152                   int entries, int bitmaps)
1153 {
1154         struct btrfs_key key;
1155         struct btrfs_free_space_header *header;
1156         struct extent_buffer *leaf;
1157         int ret;
1158
1159         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
1160         key.offset = offset;
1161         key.type = 0;
1162
1163         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1164         if (ret < 0) {
1165                 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
1166                                  EXTENT_DELALLOC, NULL);
1167                 goto fail;
1168         }
1169         leaf = path->nodes[0];
1170         if (ret > 0) {
1171                 struct btrfs_key found_key;
1172                 ASSERT(path->slots[0]);
1173                 path->slots[0]--;
1174                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1175                 if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
1176                     found_key.offset != offset) {
1177                         clear_extent_bit(&BTRFS_I(inode)->io_tree, 0,
1178                                          inode->i_size - 1, EXTENT_DELALLOC,
1179                                          NULL);
1180                         btrfs_release_path(path);
1181                         goto fail;
1182                 }
1183         }
1184
1185         BTRFS_I(inode)->generation = trans->transid;
1186         header = btrfs_item_ptr(leaf, path->slots[0],
1187                                 struct btrfs_free_space_header);
1188         btrfs_set_free_space_entries(leaf, header, entries);
1189         btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
1190         btrfs_set_free_space_generation(leaf, header, trans->transid);
1191         btrfs_mark_buffer_dirty(trans, leaf);
1192         btrfs_release_path(path);
1193
1194         return 0;
1195
1196 fail:
1197         return -1;
1198 }
1199
1200 static noinline_for_stack int write_pinned_extent_entries(
1201                             struct btrfs_trans_handle *trans,
1202                             struct btrfs_block_group *block_group,
1203                             struct btrfs_io_ctl *io_ctl,
1204                             int *entries)
1205 {
1206         u64 start, extent_start, extent_end, len;
1207         struct extent_io_tree *unpin = NULL;
1208         int ret;
1209
1210         if (!block_group)
1211                 return 0;
1212
1213         /*
1214          * We want to add any pinned extents to our free space cache
1215          * so we don't leak the space
1216          *
1217          * We shouldn't have switched the pinned extents yet so this is the
1218          * right one
1219          */
1220         unpin = &trans->transaction->pinned_extents;
1221
1222         start = block_group->start;
1223
1224         while (start < block_group->start + block_group->length) {
1225                 if (!find_first_extent_bit(unpin, start,
1226                                            &extent_start, &extent_end,
1227                                            EXTENT_DIRTY, NULL))
1228                         return 0;
1229
1230                 /* This pinned extent is out of our range */
1231                 if (extent_start >= block_group->start + block_group->length)
1232                         return 0;
1233
1234                 extent_start = max(extent_start, start);
1235                 extent_end = min(block_group->start + block_group->length,
1236                                  extent_end + 1);
1237                 len = extent_end - extent_start;
1238
1239                 *entries += 1;
1240                 ret = io_ctl_add_entry(io_ctl, extent_start, len, NULL);
1241                 if (ret)
1242                         return -ENOSPC;
1243
1244                 start = extent_end;
1245         }
1246
1247         return 0;
1248 }
1249
1250 static noinline_for_stack int
1251 write_bitmap_entries(struct btrfs_io_ctl *io_ctl, struct list_head *bitmap_list)
1252 {
1253         struct btrfs_free_space *entry, *next;
1254         int ret;
1255
1256         /* Write out the bitmaps */
1257         list_for_each_entry_safe(entry, next, bitmap_list, list) {
1258                 ret = io_ctl_add_bitmap(io_ctl, entry->bitmap);
1259                 if (ret)
1260                         return -ENOSPC;
1261                 list_del_init(&entry->list);
1262         }
1263
1264         return 0;
1265 }
1266
1267 static int flush_dirty_cache(struct inode *inode)
1268 {
1269         int ret;
1270
1271         ret = btrfs_wait_ordered_range(BTRFS_I(inode), 0, (u64)-1);
1272         if (ret)
1273                 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
1274                                  EXTENT_DELALLOC, NULL);
1275
1276         return ret;
1277 }
1278
1279 static void noinline_for_stack
1280 cleanup_bitmap_list(struct list_head *bitmap_list)
1281 {
1282         struct btrfs_free_space *entry, *next;
1283
1284         list_for_each_entry_safe(entry, next, bitmap_list, list)
1285                 list_del_init(&entry->list);
1286 }
1287
1288 static void noinline_for_stack
1289 cleanup_write_cache_enospc(struct inode *inode,
1290                            struct btrfs_io_ctl *io_ctl,
1291                            struct extent_state **cached_state)
1292 {
1293         io_ctl_drop_pages(io_ctl);
1294         unlock_extent(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
1295                       cached_state);
1296 }
1297
1298 static int __btrfs_wait_cache_io(struct btrfs_root *root,
1299                                  struct btrfs_trans_handle *trans,
1300                                  struct btrfs_block_group *block_group,
1301                                  struct btrfs_io_ctl *io_ctl,
1302                                  struct btrfs_path *path, u64 offset)
1303 {
1304         int ret;
1305         struct inode *inode = io_ctl->inode;
1306
1307         if (!inode)
1308                 return 0;
1309
1310         /* Flush the dirty pages in the cache file. */
1311         ret = flush_dirty_cache(inode);
1312         if (ret)
1313                 goto out;
1314
1315         /* Update the cache item to tell everyone this cache file is valid. */
1316         ret = update_cache_item(trans, root, inode, path, offset,
1317                                 io_ctl->entries, io_ctl->bitmaps);
1318 out:
1319         if (ret) {
1320                 invalidate_inode_pages2(inode->i_mapping);
1321                 BTRFS_I(inode)->generation = 0;
1322                 if (block_group)
1323                         btrfs_debug(root->fs_info,
1324           "failed to write free space cache for block group %llu error %d",
1325                                   block_group->start, ret);
1326         }
1327         btrfs_update_inode(trans, BTRFS_I(inode));
1328
1329         if (block_group) {
1330                 /* the dirty list is protected by the dirty_bgs_lock */
1331                 spin_lock(&trans->transaction->dirty_bgs_lock);
1332
1333                 /* the disk_cache_state is protected by the block group lock */
1334                 spin_lock(&block_group->lock);
1335
1336                 /*
1337                  * only mark this as written if we didn't get put back on
1338                  * the dirty list while waiting for IO.   Otherwise our
1339                  * cache state won't be right, and we won't get written again
1340                  */
1341                 if (!ret && list_empty(&block_group->dirty_list))
1342                         block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1343                 else if (ret)
1344                         block_group->disk_cache_state = BTRFS_DC_ERROR;
1345
1346                 spin_unlock(&block_group->lock);
1347                 spin_unlock(&trans->transaction->dirty_bgs_lock);
1348                 io_ctl->inode = NULL;
1349                 iput(inode);
1350         }
1351
1352         return ret;
1353
1354 }
1355
1356 int btrfs_wait_cache_io(struct btrfs_trans_handle *trans,
1357                         struct btrfs_block_group *block_group,
1358                         struct btrfs_path *path)
1359 {
1360         return __btrfs_wait_cache_io(block_group->fs_info->tree_root, trans,
1361                                      block_group, &block_group->io_ctl,
1362                                      path, block_group->start);
1363 }
1364
1365 /*
1366  * Write out cached info to an inode.
1367  *
1368  * @inode:       freespace inode we are writing out
1369  * @ctl:         free space cache we are going to write out
1370  * @block_group: block_group for this cache if it belongs to a block_group
1371  * @io_ctl:      holds context for the io
1372  * @trans:       the trans handle
1373  *
1374  * This function writes out a free space cache struct to disk for quick recovery
1375  * on mount.  This will return 0 if it was successful in writing the cache out,
1376  * or an errno if it was not.
1377  */
1378 static int __btrfs_write_out_cache(struct inode *inode,
1379                                    struct btrfs_free_space_ctl *ctl,
1380                                    struct btrfs_block_group *block_group,
1381                                    struct btrfs_io_ctl *io_ctl,
1382                                    struct btrfs_trans_handle *trans)
1383 {
1384         struct extent_state *cached_state = NULL;
1385         LIST_HEAD(bitmap_list);
1386         int entries = 0;
1387         int bitmaps = 0;
1388         int ret;
1389         int must_iput = 0;
1390
1391         if (!i_size_read(inode))
1392                 return -EIO;
1393
1394         WARN_ON(io_ctl->pages);
1395         ret = io_ctl_init(io_ctl, inode, 1);
1396         if (ret)
1397                 return ret;
1398
1399         if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA)) {
1400                 down_write(&block_group->data_rwsem);
1401                 spin_lock(&block_group->lock);
1402                 if (block_group->delalloc_bytes) {
1403                         block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1404                         spin_unlock(&block_group->lock);
1405                         up_write(&block_group->data_rwsem);
1406                         BTRFS_I(inode)->generation = 0;
1407                         ret = 0;
1408                         must_iput = 1;
1409                         goto out;
1410                 }
1411                 spin_unlock(&block_group->lock);
1412         }
1413
1414         /* Lock all pages first so we can lock the extent safely. */
1415         ret = io_ctl_prepare_pages(io_ctl, false);
1416         if (ret)
1417                 goto out_unlock;
1418
1419         lock_extent(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
1420                     &cached_state);
1421
1422         io_ctl_set_generation(io_ctl, trans->transid);
1423
1424         mutex_lock(&ctl->cache_writeout_mutex);
1425         /* Write out the extent entries in the free space cache */
1426         spin_lock(&ctl->tree_lock);
1427         ret = write_cache_extent_entries(io_ctl, ctl,
1428                                          block_group, &entries, &bitmaps,
1429                                          &bitmap_list);
1430         if (ret)
1431                 goto out_nospc_locked;
1432
1433         /*
1434          * Some spaces that are freed in the current transaction are pinned,
1435          * they will be added into free space cache after the transaction is
1436          * committed, we shouldn't lose them.
1437          *
1438          * If this changes while we are working we'll get added back to
1439          * the dirty list and redo it.  No locking needed
1440          */
1441         ret = write_pinned_extent_entries(trans, block_group, io_ctl, &entries);
1442         if (ret)
1443                 goto out_nospc_locked;
1444
1445         /*
1446          * At last, we write out all the bitmaps and keep cache_writeout_mutex
1447          * locked while doing it because a concurrent trim can be manipulating
1448          * or freeing the bitmap.
1449          */
1450         ret = write_bitmap_entries(io_ctl, &bitmap_list);
1451         spin_unlock(&ctl->tree_lock);
1452         mutex_unlock(&ctl->cache_writeout_mutex);
1453         if (ret)
1454                 goto out_nospc;
1455
1456         /* Zero out the rest of the pages just to make sure */
1457         io_ctl_zero_remaining_pages(io_ctl);
1458
1459         /* Everything is written out, now we dirty the pages in the file. */
1460         ret = btrfs_dirty_pages(BTRFS_I(inode), io_ctl->pages,
1461                                 io_ctl->num_pages, 0, i_size_read(inode),
1462                                 &cached_state, false);
1463         if (ret)
1464                 goto out_nospc;
1465
1466         if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1467                 up_write(&block_group->data_rwsem);
1468         /*
1469          * Release the pages and unlock the extent, we will flush
1470          * them out later
1471          */
1472         io_ctl_drop_pages(io_ctl);
1473         io_ctl_free(io_ctl);
1474
1475         unlock_extent(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
1476                       &cached_state);
1477
1478         /*
1479          * at this point the pages are under IO and we're happy,
1480          * The caller is responsible for waiting on them and updating
1481          * the cache and the inode
1482          */
1483         io_ctl->entries = entries;
1484         io_ctl->bitmaps = bitmaps;
1485
1486         ret = btrfs_fdatawrite_range(BTRFS_I(inode), 0, (u64)-1);
1487         if (ret)
1488                 goto out;
1489
1490         return 0;
1491
1492 out_nospc_locked:
1493         cleanup_bitmap_list(&bitmap_list);
1494         spin_unlock(&ctl->tree_lock);
1495         mutex_unlock(&ctl->cache_writeout_mutex);
1496
1497 out_nospc:
1498         cleanup_write_cache_enospc(inode, io_ctl, &cached_state);
1499
1500 out_unlock:
1501         if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1502                 up_write(&block_group->data_rwsem);
1503
1504 out:
1505         io_ctl->inode = NULL;
1506         io_ctl_free(io_ctl);
1507         if (ret) {
1508                 invalidate_inode_pages2(inode->i_mapping);
1509                 BTRFS_I(inode)->generation = 0;
1510         }
1511         btrfs_update_inode(trans, BTRFS_I(inode));
1512         if (must_iput)
1513                 iput(inode);
1514         return ret;
1515 }
1516
1517 int btrfs_write_out_cache(struct btrfs_trans_handle *trans,
1518                           struct btrfs_block_group *block_group,
1519                           struct btrfs_path *path)
1520 {
1521         struct btrfs_fs_info *fs_info = trans->fs_info;
1522         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1523         struct inode *inode;
1524         int ret = 0;
1525
1526         spin_lock(&block_group->lock);
1527         if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
1528                 spin_unlock(&block_group->lock);
1529                 return 0;
1530         }
1531         spin_unlock(&block_group->lock);
1532
1533         inode = lookup_free_space_inode(block_group, path);
1534         if (IS_ERR(inode))
1535                 return 0;
1536
1537         ret = __btrfs_write_out_cache(inode, ctl, block_group,
1538                                       &block_group->io_ctl, trans);
1539         if (ret) {
1540                 btrfs_debug(fs_info,
1541           "failed to write free space cache for block group %llu error %d",
1542                           block_group->start, ret);
1543                 spin_lock(&block_group->lock);
1544                 block_group->disk_cache_state = BTRFS_DC_ERROR;
1545                 spin_unlock(&block_group->lock);
1546
1547                 block_group->io_ctl.inode = NULL;
1548                 iput(inode);
1549         }
1550
1551         /*
1552          * if ret == 0 the caller is expected to call btrfs_wait_cache_io
1553          * to wait for IO and put the inode
1554          */
1555
1556         return ret;
1557 }
1558
1559 static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
1560                                           u64 offset)
1561 {
1562         ASSERT(offset >= bitmap_start);
1563         offset -= bitmap_start;
1564         return (unsigned long)(div_u64(offset, unit));
1565 }
1566
1567 static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
1568 {
1569         return (unsigned long)(div_u64(bytes, unit));
1570 }
1571
1572 static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
1573                                    u64 offset)
1574 {
1575         u64 bitmap_start;
1576         u64 bytes_per_bitmap;
1577
1578         bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
1579         bitmap_start = offset - ctl->start;
1580         bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap);
1581         bitmap_start *= bytes_per_bitmap;
1582         bitmap_start += ctl->start;
1583
1584         return bitmap_start;
1585 }
1586
1587 static int tree_insert_offset(struct btrfs_free_space_ctl *ctl,
1588                               struct btrfs_free_cluster *cluster,
1589                               struct btrfs_free_space *new_entry)
1590 {
1591         struct rb_root *root;
1592         struct rb_node **p;
1593         struct rb_node *parent = NULL;
1594
1595         lockdep_assert_held(&ctl->tree_lock);
1596
1597         if (cluster) {
1598                 lockdep_assert_held(&cluster->lock);
1599                 root = &cluster->root;
1600         } else {
1601                 root = &ctl->free_space_offset;
1602         }
1603
1604         p = &root->rb_node;
1605
1606         while (*p) {
1607                 struct btrfs_free_space *info;
1608
1609                 parent = *p;
1610                 info = rb_entry(parent, struct btrfs_free_space, offset_index);
1611
1612                 if (new_entry->offset < info->offset) {
1613                         p = &(*p)->rb_left;
1614                 } else if (new_entry->offset > info->offset) {
1615                         p = &(*p)->rb_right;
1616                 } else {
1617                         /*
1618                          * we could have a bitmap entry and an extent entry
1619                          * share the same offset.  If this is the case, we want
1620                          * the extent entry to always be found first if we do a
1621                          * linear search through the tree, since we want to have
1622                          * the quickest allocation time, and allocating from an
1623                          * extent is faster than allocating from a bitmap.  So
1624                          * if we're inserting a bitmap and we find an entry at
1625                          * this offset, we want to go right, or after this entry
1626                          * logically.  If we are inserting an extent and we've
1627                          * found a bitmap, we want to go left, or before
1628                          * logically.
1629                          */
1630                         if (new_entry->bitmap) {
1631                                 if (info->bitmap) {
1632                                         WARN_ON_ONCE(1);
1633                                         return -EEXIST;
1634                                 }
1635                                 p = &(*p)->rb_right;
1636                         } else {
1637                                 if (!info->bitmap) {
1638                                         WARN_ON_ONCE(1);
1639                                         return -EEXIST;
1640                                 }
1641                                 p = &(*p)->rb_left;
1642                         }
1643                 }
1644         }
1645
1646         rb_link_node(&new_entry->offset_index, parent, p);
1647         rb_insert_color(&new_entry->offset_index, root);
1648
1649         return 0;
1650 }
1651
1652 /*
1653  * This is a little subtle.  We *only* have ->max_extent_size set if we actually
1654  * searched through the bitmap and figured out the largest ->max_extent_size,
1655  * otherwise it's 0.  In the case that it's 0 we don't want to tell the
1656  * allocator the wrong thing, we want to use the actual real max_extent_size
1657  * we've found already if it's larger, or we want to use ->bytes.
1658  *
1659  * This matters because find_free_space() will skip entries who's ->bytes is
1660  * less than the required bytes.  So if we didn't search down this bitmap, we
1661  * may pick some previous entry that has a smaller ->max_extent_size than we
1662  * have.  For example, assume we have two entries, one that has
1663  * ->max_extent_size set to 4K and ->bytes set to 1M.  A second entry hasn't set
1664  * ->max_extent_size yet, has ->bytes set to 8K and it's contiguous.  We will
1665  *  call into find_free_space(), and return with max_extent_size == 4K, because
1666  *  that first bitmap entry had ->max_extent_size set, but the second one did
1667  *  not.  If instead we returned 8K we'd come in searching for 8K, and find the
1668  *  8K contiguous range.
1669  *
1670  *  Consider the other case, we have 2 8K chunks in that second entry and still
1671  *  don't have ->max_extent_size set.  We'll return 16K, and the next time the
1672  *  allocator comes in it'll fully search our second bitmap, and this time it'll
1673  *  get an uptodate value of 8K as the maximum chunk size.  Then we'll get the
1674  *  right allocation the next loop through.
1675  */
1676 static inline u64 get_max_extent_size(const struct btrfs_free_space *entry)
1677 {
1678         if (entry->bitmap && entry->max_extent_size)
1679                 return entry->max_extent_size;
1680         return entry->bytes;
1681 }
1682
1683 /*
1684  * We want the largest entry to be leftmost, so this is inverted from what you'd
1685  * normally expect.
1686  */
1687 static bool entry_less(struct rb_node *node, const struct rb_node *parent)
1688 {
1689         const struct btrfs_free_space *entry, *exist;
1690
1691         entry = rb_entry(node, struct btrfs_free_space, bytes_index);
1692         exist = rb_entry(parent, struct btrfs_free_space, bytes_index);
1693         return get_max_extent_size(exist) < get_max_extent_size(entry);
1694 }
1695
1696 /*
1697  * searches the tree for the given offset.
1698  *
1699  * fuzzy - If this is set, then we are trying to make an allocation, and we just
1700  * want a section that has at least bytes size and comes at or after the given
1701  * offset.
1702  */
1703 static struct btrfs_free_space *
1704 tree_search_offset(struct btrfs_free_space_ctl *ctl,
1705                    u64 offset, int bitmap_only, int fuzzy)
1706 {
1707         struct rb_node *n = ctl->free_space_offset.rb_node;
1708         struct btrfs_free_space *entry = NULL, *prev = NULL;
1709
1710         lockdep_assert_held(&ctl->tree_lock);
1711
1712         /* find entry that is closest to the 'offset' */
1713         while (n) {
1714                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1715                 prev = entry;
1716
1717                 if (offset < entry->offset)
1718                         n = n->rb_left;
1719                 else if (offset > entry->offset)
1720                         n = n->rb_right;
1721                 else
1722                         break;
1723
1724                 entry = NULL;
1725         }
1726
1727         if (bitmap_only) {
1728                 if (!entry)
1729                         return NULL;
1730                 if (entry->bitmap)
1731                         return entry;
1732
1733                 /*
1734                  * bitmap entry and extent entry may share same offset,
1735                  * in that case, bitmap entry comes after extent entry.
1736                  */
1737                 n = rb_next(n);
1738                 if (!n)
1739                         return NULL;
1740                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1741                 if (entry->offset != offset)
1742                         return NULL;
1743
1744                 WARN_ON(!entry->bitmap);
1745                 return entry;
1746         } else if (entry) {
1747                 if (entry->bitmap) {
1748                         /*
1749                          * if previous extent entry covers the offset,
1750                          * we should return it instead of the bitmap entry
1751                          */
1752                         n = rb_prev(&entry->offset_index);
1753                         if (n) {
1754                                 prev = rb_entry(n, struct btrfs_free_space,
1755                                                 offset_index);
1756                                 if (!prev->bitmap &&
1757                                     prev->offset + prev->bytes > offset)
1758                                         entry = prev;
1759                         }
1760                 }
1761                 return entry;
1762         }
1763
1764         if (!prev)
1765                 return NULL;
1766
1767         /* find last entry before the 'offset' */
1768         entry = prev;
1769         if (entry->offset > offset) {
1770                 n = rb_prev(&entry->offset_index);
1771                 if (n) {
1772                         entry = rb_entry(n, struct btrfs_free_space,
1773                                         offset_index);
1774                         ASSERT(entry->offset <= offset);
1775                 } else {
1776                         if (fuzzy)
1777                                 return entry;
1778                         else
1779                                 return NULL;
1780                 }
1781         }
1782
1783         if (entry->bitmap) {
1784                 n = rb_prev(&entry->offset_index);
1785                 if (n) {
1786                         prev = rb_entry(n, struct btrfs_free_space,
1787                                         offset_index);
1788                         if (!prev->bitmap &&
1789                             prev->offset + prev->bytes > offset)
1790                                 return prev;
1791                 }
1792                 if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1793                         return entry;
1794         } else if (entry->offset + entry->bytes > offset)
1795                 return entry;
1796
1797         if (!fuzzy)
1798                 return NULL;
1799
1800         while (1) {
1801                 n = rb_next(&entry->offset_index);
1802                 if (!n)
1803                         return NULL;
1804                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1805                 if (entry->bitmap) {
1806                         if (entry->offset + BITS_PER_BITMAP *
1807                             ctl->unit > offset)
1808                                 break;
1809                 } else {
1810                         if (entry->offset + entry->bytes > offset)
1811                                 break;
1812                 }
1813         }
1814         return entry;
1815 }
1816
1817 static inline void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1818                                      struct btrfs_free_space *info,
1819                                      bool update_stat)
1820 {
1821         lockdep_assert_held(&ctl->tree_lock);
1822
1823         rb_erase(&info->offset_index, &ctl->free_space_offset);
1824         rb_erase_cached(&info->bytes_index, &ctl->free_space_bytes);
1825         ctl->free_extents--;
1826
1827         if (!info->bitmap && !btrfs_free_space_trimmed(info)) {
1828                 ctl->discardable_extents[BTRFS_STAT_CURR]--;
1829                 ctl->discardable_bytes[BTRFS_STAT_CURR] -= info->bytes;
1830         }
1831
1832         if (update_stat)
1833                 ctl->free_space -= info->bytes;
1834 }
1835
1836 static int link_free_space(struct btrfs_free_space_ctl *ctl,
1837                            struct btrfs_free_space *info)
1838 {
1839         int ret = 0;
1840
1841         lockdep_assert_held(&ctl->tree_lock);
1842
1843         ASSERT(info->bytes || info->bitmap);
1844         ret = tree_insert_offset(ctl, NULL, info);
1845         if (ret)
1846                 return ret;
1847
1848         rb_add_cached(&info->bytes_index, &ctl->free_space_bytes, entry_less);
1849
1850         if (!info->bitmap && !btrfs_free_space_trimmed(info)) {
1851                 ctl->discardable_extents[BTRFS_STAT_CURR]++;
1852                 ctl->discardable_bytes[BTRFS_STAT_CURR] += info->bytes;
1853         }
1854
1855         ctl->free_space += info->bytes;
1856         ctl->free_extents++;
1857         return ret;
1858 }
1859
1860 static void relink_bitmap_entry(struct btrfs_free_space_ctl *ctl,
1861                                 struct btrfs_free_space *info)
1862 {
1863         ASSERT(info->bitmap);
1864
1865         /*
1866          * If our entry is empty it's because we're on a cluster and we don't
1867          * want to re-link it into our ctl bytes index.
1868          */
1869         if (RB_EMPTY_NODE(&info->bytes_index))
1870                 return;
1871
1872         lockdep_assert_held(&ctl->tree_lock);
1873
1874         rb_erase_cached(&info->bytes_index, &ctl->free_space_bytes);
1875         rb_add_cached(&info->bytes_index, &ctl->free_space_bytes, entry_less);
1876 }
1877
1878 static inline void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1879                                      struct btrfs_free_space *info,
1880                                      u64 offset, u64 bytes, bool update_stat)
1881 {
1882         unsigned long start, count, end;
1883         int extent_delta = -1;
1884
1885         start = offset_to_bit(info->offset, ctl->unit, offset);
1886         count = bytes_to_bits(bytes, ctl->unit);
1887         end = start + count;
1888         ASSERT(end <= BITS_PER_BITMAP);
1889
1890         bitmap_clear(info->bitmap, start, count);
1891
1892         info->bytes -= bytes;
1893         if (info->max_extent_size > ctl->unit)
1894                 info->max_extent_size = 0;
1895
1896         relink_bitmap_entry(ctl, info);
1897
1898         if (start && test_bit(start - 1, info->bitmap))
1899                 extent_delta++;
1900
1901         if (end < BITS_PER_BITMAP && test_bit(end, info->bitmap))
1902                 extent_delta++;
1903
1904         info->bitmap_extents += extent_delta;
1905         if (!btrfs_free_space_trimmed(info)) {
1906                 ctl->discardable_extents[BTRFS_STAT_CURR] += extent_delta;
1907                 ctl->discardable_bytes[BTRFS_STAT_CURR] -= bytes;
1908         }
1909
1910         if (update_stat)
1911                 ctl->free_space -= bytes;
1912 }
1913
1914 static void btrfs_bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
1915                                   struct btrfs_free_space *info, u64 offset,
1916                                   u64 bytes)
1917 {
1918         unsigned long start, count, end;
1919         int extent_delta = 1;
1920
1921         start = offset_to_bit(info->offset, ctl->unit, offset);
1922         count = bytes_to_bits(bytes, ctl->unit);
1923         end = start + count;
1924         ASSERT(end <= BITS_PER_BITMAP);
1925
1926         bitmap_set(info->bitmap, start, count);
1927
1928         /*
1929          * We set some bytes, we have no idea what the max extent size is
1930          * anymore.
1931          */
1932         info->max_extent_size = 0;
1933         info->bytes += bytes;
1934         ctl->free_space += bytes;
1935
1936         relink_bitmap_entry(ctl, info);
1937
1938         if (start && test_bit(start - 1, info->bitmap))
1939                 extent_delta--;
1940
1941         if (end < BITS_PER_BITMAP && test_bit(end, info->bitmap))
1942                 extent_delta--;
1943
1944         info->bitmap_extents += extent_delta;
1945         if (!btrfs_free_space_trimmed(info)) {
1946                 ctl->discardable_extents[BTRFS_STAT_CURR] += extent_delta;
1947                 ctl->discardable_bytes[BTRFS_STAT_CURR] += bytes;
1948         }
1949 }
1950
1951 /*
1952  * If we can not find suitable extent, we will use bytes to record
1953  * the size of the max extent.
1954  */
1955 static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1956                          struct btrfs_free_space *bitmap_info, u64 *offset,
1957                          u64 *bytes, bool for_alloc)
1958 {
1959         unsigned long found_bits = 0;
1960         unsigned long max_bits = 0;
1961         unsigned long bits, i;
1962         unsigned long next_zero;
1963         unsigned long extent_bits;
1964
1965         /*
1966          * Skip searching the bitmap if we don't have a contiguous section that
1967          * is large enough for this allocation.
1968          */
1969         if (for_alloc &&
1970             bitmap_info->max_extent_size &&
1971             bitmap_info->max_extent_size < *bytes) {
1972                 *bytes = bitmap_info->max_extent_size;
1973                 return -1;
1974         }
1975
1976         i = offset_to_bit(bitmap_info->offset, ctl->unit,
1977                           max_t(u64, *offset, bitmap_info->offset));
1978         bits = bytes_to_bits(*bytes, ctl->unit);
1979
1980         for_each_set_bit_from(i, bitmap_info->bitmap, BITS_PER_BITMAP) {
1981                 if (for_alloc && bits == 1) {
1982                         found_bits = 1;
1983                         break;
1984                 }
1985                 next_zero = find_next_zero_bit(bitmap_info->bitmap,
1986                                                BITS_PER_BITMAP, i);
1987                 extent_bits = next_zero - i;
1988                 if (extent_bits >= bits) {
1989                         found_bits = extent_bits;
1990                         break;
1991                 } else if (extent_bits > max_bits) {
1992                         max_bits = extent_bits;
1993                 }
1994                 i = next_zero;
1995         }
1996
1997         if (found_bits) {
1998                 *offset = (u64)(i * ctl->unit) + bitmap_info->offset;
1999                 *bytes = (u64)(found_bits) * ctl->unit;
2000                 return 0;
2001         }
2002
2003         *bytes = (u64)(max_bits) * ctl->unit;
2004         bitmap_info->max_extent_size = *bytes;
2005         relink_bitmap_entry(ctl, bitmap_info);
2006         return -1;
2007 }
2008
2009 /* Cache the size of the max extent in bytes */
2010 static struct btrfs_free_space *
2011 find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes,
2012                 unsigned long align, u64 *max_extent_size, bool use_bytes_index)
2013 {
2014         struct btrfs_free_space *entry;
2015         struct rb_node *node;
2016         u64 tmp;
2017         u64 align_off;
2018         int ret;
2019
2020         if (!ctl->free_space_offset.rb_node)
2021                 goto out;
2022 again:
2023         if (use_bytes_index) {
2024                 node = rb_first_cached(&ctl->free_space_bytes);
2025         } else {
2026                 entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset),
2027                                            0, 1);
2028                 if (!entry)
2029                         goto out;
2030                 node = &entry->offset_index;
2031         }
2032
2033         for (; node; node = rb_next(node)) {
2034                 if (use_bytes_index)
2035                         entry = rb_entry(node, struct btrfs_free_space,
2036                                          bytes_index);
2037                 else
2038                         entry = rb_entry(node, struct btrfs_free_space,
2039                                          offset_index);
2040
2041                 /*
2042                  * If we are using the bytes index then all subsequent entries
2043                  * in this tree are going to be < bytes, so simply set the max
2044                  * extent size and exit the loop.
2045                  *
2046                  * If we're using the offset index then we need to keep going
2047                  * through the rest of the tree.
2048                  */
2049                 if (entry->bytes < *bytes) {
2050                         *max_extent_size = max(get_max_extent_size(entry),
2051                                                *max_extent_size);
2052                         if (use_bytes_index)
2053                                 break;
2054                         continue;
2055                 }
2056
2057                 /* make sure the space returned is big enough
2058                  * to match our requested alignment
2059                  */
2060                 if (*bytes >= align) {
2061                         tmp = entry->offset - ctl->start + align - 1;
2062                         tmp = div64_u64(tmp, align);
2063                         tmp = tmp * align + ctl->start;
2064                         align_off = tmp - entry->offset;
2065                 } else {
2066                         align_off = 0;
2067                         tmp = entry->offset;
2068                 }
2069
2070                 /*
2071                  * We don't break here if we're using the bytes index because we
2072                  * may have another entry that has the correct alignment that is
2073                  * the right size, so we don't want to miss that possibility.
2074                  * At worst this adds another loop through the logic, but if we
2075                  * broke here we could prematurely ENOSPC.
2076                  */
2077                 if (entry->bytes < *bytes + align_off) {
2078                         *max_extent_size = max(get_max_extent_size(entry),
2079                                                *max_extent_size);
2080                         continue;
2081                 }
2082
2083                 if (entry->bitmap) {
2084                         struct rb_node *old_next = rb_next(node);
2085                         u64 size = *bytes;
2086
2087                         ret = search_bitmap(ctl, entry, &tmp, &size, true);
2088                         if (!ret) {
2089                                 *offset = tmp;
2090                                 *bytes = size;
2091                                 return entry;
2092                         } else {
2093                                 *max_extent_size =
2094                                         max(get_max_extent_size(entry),
2095                                             *max_extent_size);
2096                         }
2097
2098                         /*
2099                          * The bitmap may have gotten re-arranged in the space
2100                          * index here because the max_extent_size may have been
2101                          * updated.  Start from the beginning again if this
2102                          * happened.
2103                          */
2104                         if (use_bytes_index && old_next != rb_next(node))
2105                                 goto again;
2106                         continue;
2107                 }
2108
2109                 *offset = tmp;
2110                 *bytes = entry->bytes - align_off;
2111                 return entry;
2112         }
2113 out:
2114         return NULL;
2115 }
2116
2117 static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
2118                            struct btrfs_free_space *info, u64 offset)
2119 {
2120         info->offset = offset_to_bitmap(ctl, offset);
2121         info->bytes = 0;
2122         info->bitmap_extents = 0;
2123         INIT_LIST_HEAD(&info->list);
2124         link_free_space(ctl, info);
2125         ctl->total_bitmaps++;
2126         recalculate_thresholds(ctl);
2127 }
2128
2129 static void free_bitmap(struct btrfs_free_space_ctl *ctl,
2130                         struct btrfs_free_space *bitmap_info)
2131 {
2132         /*
2133          * Normally when this is called, the bitmap is completely empty. However,
2134          * if we are blowing up the free space cache for one reason or another
2135          * via __btrfs_remove_free_space_cache(), then it may not be freed and
2136          * we may leave stats on the table.
2137          */
2138         if (bitmap_info->bytes && !btrfs_free_space_trimmed(bitmap_info)) {
2139                 ctl->discardable_extents[BTRFS_STAT_CURR] -=
2140                         bitmap_info->bitmap_extents;
2141                 ctl->discardable_bytes[BTRFS_STAT_CURR] -= bitmap_info->bytes;
2142
2143         }
2144         unlink_free_space(ctl, bitmap_info, true);
2145         kmem_cache_free(btrfs_free_space_bitmap_cachep, bitmap_info->bitmap);
2146         kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
2147         ctl->total_bitmaps--;
2148         recalculate_thresholds(ctl);
2149 }
2150
2151 static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
2152                               struct btrfs_free_space *bitmap_info,
2153                               u64 *offset, u64 *bytes)
2154 {
2155         u64 end;
2156         u64 search_start, search_bytes;
2157         int ret;
2158
2159 again:
2160         end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
2161
2162         /*
2163          * We need to search for bits in this bitmap.  We could only cover some
2164          * of the extent in this bitmap thanks to how we add space, so we need
2165          * to search for as much as it as we can and clear that amount, and then
2166          * go searching for the next bit.
2167          */
2168         search_start = *offset;
2169         search_bytes = ctl->unit;
2170         search_bytes = min(search_bytes, end - search_start + 1);
2171         ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes,
2172                             false);
2173         if (ret < 0 || search_start != *offset)
2174                 return -EINVAL;
2175
2176         /* We may have found more bits than what we need */
2177         search_bytes = min(search_bytes, *bytes);
2178
2179         /* Cannot clear past the end of the bitmap */
2180         search_bytes = min(search_bytes, end - search_start + 1);
2181
2182         bitmap_clear_bits(ctl, bitmap_info, search_start, search_bytes, true);
2183         *offset += search_bytes;
2184         *bytes -= search_bytes;
2185
2186         if (*bytes) {
2187                 struct rb_node *next = rb_next(&bitmap_info->offset_index);
2188                 if (!bitmap_info->bytes)
2189                         free_bitmap(ctl, bitmap_info);
2190
2191                 /*
2192                  * no entry after this bitmap, but we still have bytes to
2193                  * remove, so something has gone wrong.
2194                  */
2195                 if (!next)
2196                         return -EINVAL;
2197
2198                 bitmap_info = rb_entry(next, struct btrfs_free_space,
2199                                        offset_index);
2200
2201                 /*
2202                  * if the next entry isn't a bitmap we need to return to let the
2203                  * extent stuff do its work.
2204                  */
2205                 if (!bitmap_info->bitmap)
2206                         return -EAGAIN;
2207
2208                 /*
2209                  * Ok the next item is a bitmap, but it may not actually hold
2210                  * the information for the rest of this free space stuff, so
2211                  * look for it, and if we don't find it return so we can try
2212                  * everything over again.
2213                  */
2214                 search_start = *offset;
2215                 search_bytes = ctl->unit;
2216                 ret = search_bitmap(ctl, bitmap_info, &search_start,
2217                                     &search_bytes, false);
2218                 if (ret < 0 || search_start != *offset)
2219                         return -EAGAIN;
2220
2221                 goto again;
2222         } else if (!bitmap_info->bytes)
2223                 free_bitmap(ctl, bitmap_info);
2224
2225         return 0;
2226 }
2227
2228 static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
2229                                struct btrfs_free_space *info, u64 offset,
2230                                u64 bytes, enum btrfs_trim_state trim_state)
2231 {
2232         u64 bytes_to_set = 0;
2233         u64 end;
2234
2235         /*
2236          * This is a tradeoff to make bitmap trim state minimal.  We mark the
2237          * whole bitmap untrimmed if at any point we add untrimmed regions.
2238          */
2239         if (trim_state == BTRFS_TRIM_STATE_UNTRIMMED) {
2240                 if (btrfs_free_space_trimmed(info)) {
2241                         ctl->discardable_extents[BTRFS_STAT_CURR] +=
2242                                 info->bitmap_extents;
2243                         ctl->discardable_bytes[BTRFS_STAT_CURR] += info->bytes;
2244                 }
2245                 info->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2246         }
2247
2248         end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
2249
2250         bytes_to_set = min(end - offset, bytes);
2251
2252         btrfs_bitmap_set_bits(ctl, info, offset, bytes_to_set);
2253
2254         return bytes_to_set;
2255
2256 }
2257
2258 static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
2259                       struct btrfs_free_space *info)
2260 {
2261         struct btrfs_block_group *block_group = ctl->block_group;
2262         struct btrfs_fs_info *fs_info = block_group->fs_info;
2263         bool forced = false;
2264
2265 #ifdef CONFIG_BTRFS_DEBUG
2266         if (btrfs_should_fragment_free_space(block_group))
2267                 forced = true;
2268 #endif
2269
2270         /* This is a way to reclaim large regions from the bitmaps. */
2271         if (!forced && info->bytes >= FORCE_EXTENT_THRESHOLD)
2272                 return false;
2273
2274         /*
2275          * If we are below the extents threshold then we can add this as an
2276          * extent, and don't have to deal with the bitmap
2277          */
2278         if (!forced && ctl->free_extents < ctl->extents_thresh) {
2279                 /*
2280                  * If this block group has some small extents we don't want to
2281                  * use up all of our free slots in the cache with them, we want
2282                  * to reserve them to larger extents, however if we have plenty
2283                  * of cache left then go ahead an dadd them, no sense in adding
2284                  * the overhead of a bitmap if we don't have to.
2285                  */
2286                 if (info->bytes <= fs_info->sectorsize * 8) {
2287                         if (ctl->free_extents * 3 <= ctl->extents_thresh)
2288                                 return false;
2289                 } else {
2290                         return false;
2291                 }
2292         }
2293
2294         /*
2295          * The original block groups from mkfs can be really small, like 8
2296          * megabytes, so don't bother with a bitmap for those entries.  However
2297          * some block groups can be smaller than what a bitmap would cover but
2298          * are still large enough that they could overflow the 32k memory limit,
2299          * so allow those block groups to still be allowed to have a bitmap
2300          * entry.
2301          */
2302         if (((BITS_PER_BITMAP * ctl->unit) >> 1) > block_group->length)
2303                 return false;
2304
2305         return true;
2306 }
2307
2308 static const struct btrfs_free_space_op free_space_op = {
2309         .use_bitmap             = use_bitmap,
2310 };
2311
2312 static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
2313                               struct btrfs_free_space *info)
2314 {
2315         struct btrfs_free_space *bitmap_info;
2316         struct btrfs_block_group *block_group = NULL;
2317         int added = 0;
2318         u64 bytes, offset, bytes_added;
2319         enum btrfs_trim_state trim_state;
2320         int ret;
2321
2322         bytes = info->bytes;
2323         offset = info->offset;
2324         trim_state = info->trim_state;
2325
2326         if (!ctl->op->use_bitmap(ctl, info))
2327                 return 0;
2328
2329         if (ctl->op == &free_space_op)
2330                 block_group = ctl->block_group;
2331 again:
2332         /*
2333          * Since we link bitmaps right into the cluster we need to see if we
2334          * have a cluster here, and if so and it has our bitmap we need to add
2335          * the free space to that bitmap.
2336          */
2337         if (block_group && !list_empty(&block_group->cluster_list)) {
2338                 struct btrfs_free_cluster *cluster;
2339                 struct rb_node *node;
2340                 struct btrfs_free_space *entry;
2341
2342                 cluster = list_entry(block_group->cluster_list.next,
2343                                      struct btrfs_free_cluster,
2344                                      block_group_list);
2345                 spin_lock(&cluster->lock);
2346                 node = rb_first(&cluster->root);
2347                 if (!node) {
2348                         spin_unlock(&cluster->lock);
2349                         goto no_cluster_bitmap;
2350                 }
2351
2352                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2353                 if (!entry->bitmap) {
2354                         spin_unlock(&cluster->lock);
2355                         goto no_cluster_bitmap;
2356                 }
2357
2358                 if (entry->offset == offset_to_bitmap(ctl, offset)) {
2359                         bytes_added = add_bytes_to_bitmap(ctl, entry, offset,
2360                                                           bytes, trim_state);
2361                         bytes -= bytes_added;
2362                         offset += bytes_added;
2363                 }
2364                 spin_unlock(&cluster->lock);
2365                 if (!bytes) {
2366                         ret = 1;
2367                         goto out;
2368                 }
2369         }
2370
2371 no_cluster_bitmap:
2372         bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
2373                                          1, 0);
2374         if (!bitmap_info) {
2375                 ASSERT(added == 0);
2376                 goto new_bitmap;
2377         }
2378
2379         bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes,
2380                                           trim_state);
2381         bytes -= bytes_added;
2382         offset += bytes_added;
2383         added = 0;
2384
2385         if (!bytes) {
2386                 ret = 1;
2387                 goto out;
2388         } else
2389                 goto again;
2390
2391 new_bitmap:
2392         if (info && info->bitmap) {
2393                 add_new_bitmap(ctl, info, offset);
2394                 added = 1;
2395                 info = NULL;
2396                 goto again;
2397         } else {
2398                 spin_unlock(&ctl->tree_lock);
2399
2400                 /* no pre-allocated info, allocate a new one */
2401                 if (!info) {
2402                         info = kmem_cache_zalloc(btrfs_free_space_cachep,
2403                                                  GFP_NOFS);
2404                         if (!info) {
2405                                 spin_lock(&ctl->tree_lock);
2406                                 ret = -ENOMEM;
2407                                 goto out;
2408                         }
2409                 }
2410
2411                 /* allocate the bitmap */
2412                 info->bitmap = kmem_cache_zalloc(btrfs_free_space_bitmap_cachep,
2413                                                  GFP_NOFS);
2414                 info->trim_state = BTRFS_TRIM_STATE_TRIMMED;
2415                 spin_lock(&ctl->tree_lock);
2416                 if (!info->bitmap) {
2417                         ret = -ENOMEM;
2418                         goto out;
2419                 }
2420                 goto again;
2421         }
2422
2423 out:
2424         if (info) {
2425                 if (info->bitmap)
2426                         kmem_cache_free(btrfs_free_space_bitmap_cachep,
2427                                         info->bitmap);
2428                 kmem_cache_free(btrfs_free_space_cachep, info);
2429         }
2430
2431         return ret;
2432 }
2433
2434 /*
2435  * Free space merging rules:
2436  *  1) Merge trimmed areas together
2437  *  2) Let untrimmed areas coalesce with trimmed areas
2438  *  3) Always pull neighboring regions from bitmaps
2439  *
2440  * The above rules are for when we merge free space based on btrfs_trim_state.
2441  * Rules 2 and 3 are subtle because they are suboptimal, but are done for the
2442  * same reason: to promote larger extent regions which makes life easier for
2443  * find_free_extent().  Rule 2 enables coalescing based on the common path
2444  * being returning free space from btrfs_finish_extent_commit().  So when free
2445  * space is trimmed, it will prevent aggregating trimmed new region and
2446  * untrimmed regions in the rb_tree.  Rule 3 is purely to obtain larger extents
2447  * and provide find_free_extent() with the largest extents possible hoping for
2448  * the reuse path.
2449  */
2450 static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
2451                           struct btrfs_free_space *info, bool update_stat)
2452 {
2453         struct btrfs_free_space *left_info = NULL;
2454         struct btrfs_free_space *right_info;
2455         bool merged = false;
2456         u64 offset = info->offset;
2457         u64 bytes = info->bytes;
2458         const bool is_trimmed = btrfs_free_space_trimmed(info);
2459         struct rb_node *right_prev = NULL;
2460
2461         /*
2462          * first we want to see if there is free space adjacent to the range we
2463          * are adding, if there is remove that struct and add a new one to
2464          * cover the entire range
2465          */
2466         right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
2467         if (right_info)
2468                 right_prev = rb_prev(&right_info->offset_index);
2469
2470         if (right_prev)
2471                 left_info = rb_entry(right_prev, struct btrfs_free_space, offset_index);
2472         else if (!right_info)
2473                 left_info = tree_search_offset(ctl, offset - 1, 0, 0);
2474
2475         /* See try_merge_free_space() comment. */
2476         if (right_info && !right_info->bitmap &&
2477             (!is_trimmed || btrfs_free_space_trimmed(right_info))) {
2478                 unlink_free_space(ctl, right_info, update_stat);
2479                 info->bytes += right_info->bytes;
2480                 kmem_cache_free(btrfs_free_space_cachep, right_info);
2481                 merged = true;
2482         }
2483
2484         /* See try_merge_free_space() comment. */
2485         if (left_info && !left_info->bitmap &&
2486             left_info->offset + left_info->bytes == offset &&
2487             (!is_trimmed || btrfs_free_space_trimmed(left_info))) {
2488                 unlink_free_space(ctl, left_info, update_stat);
2489                 info->offset = left_info->offset;
2490                 info->bytes += left_info->bytes;
2491                 kmem_cache_free(btrfs_free_space_cachep, left_info);
2492                 merged = true;
2493         }
2494
2495         return merged;
2496 }
2497
2498 static bool steal_from_bitmap_to_end(struct btrfs_free_space_ctl *ctl,
2499                                      struct btrfs_free_space *info,
2500                                      bool update_stat)
2501 {
2502         struct btrfs_free_space *bitmap;
2503         unsigned long i;
2504         unsigned long j;
2505         const u64 end = info->offset + info->bytes;
2506         const u64 bitmap_offset = offset_to_bitmap(ctl, end);
2507         u64 bytes;
2508
2509         bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0);
2510         if (!bitmap)
2511                 return false;
2512
2513         i = offset_to_bit(bitmap->offset, ctl->unit, end);
2514         j = find_next_zero_bit(bitmap->bitmap, BITS_PER_BITMAP, i);
2515         if (j == i)
2516                 return false;
2517         bytes = (j - i) * ctl->unit;
2518         info->bytes += bytes;
2519
2520         /* See try_merge_free_space() comment. */
2521         if (!btrfs_free_space_trimmed(bitmap))
2522                 info->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2523
2524         bitmap_clear_bits(ctl, bitmap, end, bytes, update_stat);
2525
2526         if (!bitmap->bytes)
2527                 free_bitmap(ctl, bitmap);
2528
2529         return true;
2530 }
2531
2532 static bool steal_from_bitmap_to_front(struct btrfs_free_space_ctl *ctl,
2533                                        struct btrfs_free_space *info,
2534                                        bool update_stat)
2535 {
2536         struct btrfs_free_space *bitmap;
2537         u64 bitmap_offset;
2538         unsigned long i;
2539         unsigned long j;
2540         unsigned long prev_j;
2541         u64 bytes;
2542
2543         bitmap_offset = offset_to_bitmap(ctl, info->offset);
2544         /* If we're on a boundary, try the previous logical bitmap. */
2545         if (bitmap_offset == info->offset) {
2546                 if (info->offset == 0)
2547                         return false;
2548                 bitmap_offset = offset_to_bitmap(ctl, info->offset - 1);
2549         }
2550
2551         bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0);
2552         if (!bitmap)
2553                 return false;
2554
2555         i = offset_to_bit(bitmap->offset, ctl->unit, info->offset) - 1;
2556         j = 0;
2557         prev_j = (unsigned long)-1;
2558         for_each_clear_bit_from(j, bitmap->bitmap, BITS_PER_BITMAP) {
2559                 if (j > i)
2560                         break;
2561                 prev_j = j;
2562         }
2563         if (prev_j == i)
2564                 return false;
2565
2566         if (prev_j == (unsigned long)-1)
2567                 bytes = (i + 1) * ctl->unit;
2568         else
2569                 bytes = (i - prev_j) * ctl->unit;
2570
2571         info->offset -= bytes;
2572         info->bytes += bytes;
2573
2574         /* See try_merge_free_space() comment. */
2575         if (!btrfs_free_space_trimmed(bitmap))
2576                 info->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2577
2578         bitmap_clear_bits(ctl, bitmap, info->offset, bytes, update_stat);
2579
2580         if (!bitmap->bytes)
2581                 free_bitmap(ctl, bitmap);
2582
2583         return true;
2584 }
2585
2586 /*
2587  * We prefer always to allocate from extent entries, both for clustered and
2588  * non-clustered allocation requests. So when attempting to add a new extent
2589  * entry, try to see if there's adjacent free space in bitmap entries, and if
2590  * there is, migrate that space from the bitmaps to the extent.
2591  * Like this we get better chances of satisfying space allocation requests
2592  * because we attempt to satisfy them based on a single cache entry, and never
2593  * on 2 or more entries - even if the entries represent a contiguous free space
2594  * region (e.g. 1 extent entry + 1 bitmap entry starting where the extent entry
2595  * ends).
2596  */
2597 static void steal_from_bitmap(struct btrfs_free_space_ctl *ctl,
2598                               struct btrfs_free_space *info,
2599                               bool update_stat)
2600 {
2601         /*
2602          * Only work with disconnected entries, as we can change their offset,
2603          * and must be extent entries.
2604          */
2605         ASSERT(!info->bitmap);
2606         ASSERT(RB_EMPTY_NODE(&info->offset_index));
2607
2608         if (ctl->total_bitmaps > 0) {
2609                 bool stole_end;
2610                 bool stole_front = false;
2611
2612                 stole_end = steal_from_bitmap_to_end(ctl, info, update_stat);
2613                 if (ctl->total_bitmaps > 0)
2614                         stole_front = steal_from_bitmap_to_front(ctl, info,
2615                                                                  update_stat);
2616
2617                 if (stole_end || stole_front)
2618                         try_merge_free_space(ctl, info, update_stat);
2619         }
2620 }
2621
2622 static int __btrfs_add_free_space(struct btrfs_block_group *block_group,
2623                            u64 offset, u64 bytes,
2624                            enum btrfs_trim_state trim_state)
2625 {
2626         struct btrfs_fs_info *fs_info = block_group->fs_info;
2627         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2628         struct btrfs_free_space *info;
2629         int ret = 0;
2630         u64 filter_bytes = bytes;
2631
2632         ASSERT(!btrfs_is_zoned(fs_info));
2633
2634         info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
2635         if (!info)
2636                 return -ENOMEM;
2637
2638         info->offset = offset;
2639         info->bytes = bytes;
2640         info->trim_state = trim_state;
2641         RB_CLEAR_NODE(&info->offset_index);
2642         RB_CLEAR_NODE(&info->bytes_index);
2643
2644         spin_lock(&ctl->tree_lock);
2645
2646         if (try_merge_free_space(ctl, info, true))
2647                 goto link;
2648
2649         /*
2650          * There was no extent directly to the left or right of this new
2651          * extent then we know we're going to have to allocate a new extent, so
2652          * before we do that see if we need to drop this into a bitmap
2653          */
2654         ret = insert_into_bitmap(ctl, info);
2655         if (ret < 0) {
2656                 goto out;
2657         } else if (ret) {
2658                 ret = 0;
2659                 goto out;
2660         }
2661 link:
2662         /*
2663          * Only steal free space from adjacent bitmaps if we're sure we're not
2664          * going to add the new free space to existing bitmap entries - because
2665          * that would mean unnecessary work that would be reverted. Therefore
2666          * attempt to steal space from bitmaps if we're adding an extent entry.
2667          */
2668         steal_from_bitmap(ctl, info, true);
2669
2670         filter_bytes = max(filter_bytes, info->bytes);
2671
2672         ret = link_free_space(ctl, info);
2673         if (ret)
2674                 kmem_cache_free(btrfs_free_space_cachep, info);
2675 out:
2676         btrfs_discard_update_discardable(block_group);
2677         spin_unlock(&ctl->tree_lock);
2678
2679         if (ret) {
2680                 btrfs_crit(fs_info, "unable to add free space :%d", ret);
2681                 ASSERT(ret != -EEXIST);
2682         }
2683
2684         if (trim_state != BTRFS_TRIM_STATE_TRIMMED) {
2685                 btrfs_discard_check_filter(block_group, filter_bytes);
2686                 btrfs_discard_queue_work(&fs_info->discard_ctl, block_group);
2687         }
2688
2689         return ret;
2690 }
2691
2692 static int __btrfs_add_free_space_zoned(struct btrfs_block_group *block_group,
2693                                         u64 bytenr, u64 size, bool used)
2694 {
2695         struct btrfs_space_info *sinfo = block_group->space_info;
2696         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2697         u64 offset = bytenr - block_group->start;
2698         u64 to_free, to_unusable;
2699         int bg_reclaim_threshold = 0;
2700         bool initial;
2701         u64 reclaimable_unusable;
2702
2703         spin_lock(&block_group->lock);
2704
2705         initial = ((size == block_group->length) && (block_group->alloc_offset == 0));
2706         WARN_ON(!initial && offset + size > block_group->zone_capacity);
2707         if (!initial)
2708                 bg_reclaim_threshold = READ_ONCE(sinfo->bg_reclaim_threshold);
2709
2710         if (!used)
2711                 to_free = size;
2712         else if (initial)
2713                 to_free = block_group->zone_capacity;
2714         else if (offset >= block_group->alloc_offset)
2715                 to_free = size;
2716         else if (offset + size <= block_group->alloc_offset)
2717                 to_free = 0;
2718         else
2719                 to_free = offset + size - block_group->alloc_offset;
2720         to_unusable = size - to_free;
2721
2722         spin_lock(&ctl->tree_lock);
2723         ctl->free_space += to_free;
2724         spin_unlock(&ctl->tree_lock);
2725         /*
2726          * If the block group is read-only, we should account freed space into
2727          * bytes_readonly.
2728          */
2729         if (!block_group->ro) {
2730                 block_group->zone_unusable += to_unusable;
2731                 WARN_ON(block_group->zone_unusable > block_group->length);
2732         }
2733         if (!used) {
2734                 block_group->alloc_offset -= size;
2735         }
2736
2737         reclaimable_unusable = block_group->zone_unusable -
2738                                (block_group->length - block_group->zone_capacity);
2739         /* All the region is now unusable. Mark it as unused and reclaim */
2740         if (block_group->zone_unusable == block_group->length) {
2741                 btrfs_mark_bg_unused(block_group);
2742         } else if (bg_reclaim_threshold &&
2743                    reclaimable_unusable >=
2744                    mult_perc(block_group->zone_capacity, bg_reclaim_threshold)) {
2745                 btrfs_mark_bg_to_reclaim(block_group);
2746         }
2747
2748         spin_unlock(&block_group->lock);
2749
2750         return 0;
2751 }
2752
2753 int btrfs_add_free_space(struct btrfs_block_group *block_group,
2754                          u64 bytenr, u64 size)
2755 {
2756         enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2757
2758         if (btrfs_is_zoned(block_group->fs_info))
2759                 return __btrfs_add_free_space_zoned(block_group, bytenr, size,
2760                                                     true);
2761
2762         if (btrfs_test_opt(block_group->fs_info, DISCARD_SYNC))
2763                 trim_state = BTRFS_TRIM_STATE_TRIMMED;
2764
2765         return __btrfs_add_free_space(block_group, bytenr, size, trim_state);
2766 }
2767
2768 int btrfs_add_free_space_unused(struct btrfs_block_group *block_group,
2769                                 u64 bytenr, u64 size)
2770 {
2771         if (btrfs_is_zoned(block_group->fs_info))
2772                 return __btrfs_add_free_space_zoned(block_group, bytenr, size,
2773                                                     false);
2774
2775         return btrfs_add_free_space(block_group, bytenr, size);
2776 }
2777
2778 /*
2779  * This is a subtle distinction because when adding free space back in general,
2780  * we want it to be added as untrimmed for async. But in the case where we add
2781  * it on loading of a block group, we want to consider it trimmed.
2782  */
2783 int btrfs_add_free_space_async_trimmed(struct btrfs_block_group *block_group,
2784                                        u64 bytenr, u64 size)
2785 {
2786         enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2787
2788         if (btrfs_is_zoned(block_group->fs_info))
2789                 return __btrfs_add_free_space_zoned(block_group, bytenr, size,
2790                                                     true);
2791
2792         if (btrfs_test_opt(block_group->fs_info, DISCARD_SYNC) ||
2793             btrfs_test_opt(block_group->fs_info, DISCARD_ASYNC))
2794                 trim_state = BTRFS_TRIM_STATE_TRIMMED;
2795
2796         return __btrfs_add_free_space(block_group, bytenr, size, trim_state);
2797 }
2798
2799 int btrfs_remove_free_space(struct btrfs_block_group *block_group,
2800                             u64 offset, u64 bytes)
2801 {
2802         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2803         struct btrfs_free_space *info;
2804         int ret;
2805         bool re_search = false;
2806
2807         if (btrfs_is_zoned(block_group->fs_info)) {
2808                 /*
2809                  * This can happen with conventional zones when replaying log.
2810                  * Since the allocation info of tree-log nodes are not recorded
2811                  * to the extent-tree, calculate_alloc_pointer() failed to
2812                  * advance the allocation pointer after last allocated tree log
2813                  * node blocks.
2814                  *
2815                  * This function is called from
2816                  * btrfs_pin_extent_for_log_replay() when replaying the log.
2817                  * Advance the pointer not to overwrite the tree-log nodes.
2818                  */
2819                 if (block_group->start + block_group->alloc_offset <
2820                     offset + bytes) {
2821                         block_group->alloc_offset =
2822                                 offset + bytes - block_group->start;
2823                 }
2824                 return 0;
2825         }
2826
2827         spin_lock(&ctl->tree_lock);
2828
2829 again:
2830         ret = 0;
2831         if (!bytes)
2832                 goto out_lock;
2833
2834         info = tree_search_offset(ctl, offset, 0, 0);
2835         if (!info) {
2836                 /*
2837                  * oops didn't find an extent that matched the space we wanted
2838                  * to remove, look for a bitmap instead
2839                  */
2840                 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
2841                                           1, 0);
2842                 if (!info) {
2843                         /*
2844                          * If we found a partial bit of our free space in a
2845                          * bitmap but then couldn't find the other part this may
2846                          * be a problem, so WARN about it.
2847                          */
2848                         WARN_ON(re_search);
2849                         goto out_lock;
2850                 }
2851         }
2852
2853         re_search = false;
2854         if (!info->bitmap) {
2855                 unlink_free_space(ctl, info, true);
2856                 if (offset == info->offset) {
2857                         u64 to_free = min(bytes, info->bytes);
2858
2859                         info->bytes -= to_free;
2860                         info->offset += to_free;
2861                         if (info->bytes) {
2862                                 ret = link_free_space(ctl, info);
2863                                 WARN_ON(ret);
2864                         } else {
2865                                 kmem_cache_free(btrfs_free_space_cachep, info);
2866                         }
2867
2868                         offset += to_free;
2869                         bytes -= to_free;
2870                         goto again;
2871                 } else {
2872                         u64 old_end = info->bytes + info->offset;
2873
2874                         info->bytes = offset - info->offset;
2875                         ret = link_free_space(ctl, info);
2876                         WARN_ON(ret);
2877                         if (ret)
2878                                 goto out_lock;
2879
2880                         /* Not enough bytes in this entry to satisfy us */
2881                         if (old_end < offset + bytes) {
2882                                 bytes -= old_end - offset;
2883                                 offset = old_end;
2884                                 goto again;
2885                         } else if (old_end == offset + bytes) {
2886                                 /* all done */
2887                                 goto out_lock;
2888                         }
2889                         spin_unlock(&ctl->tree_lock);
2890
2891                         ret = __btrfs_add_free_space(block_group,
2892                                                      offset + bytes,
2893                                                      old_end - (offset + bytes),
2894                                                      info->trim_state);
2895                         WARN_ON(ret);
2896                         goto out;
2897                 }
2898         }
2899
2900         ret = remove_from_bitmap(ctl, info, &offset, &bytes);
2901         if (ret == -EAGAIN) {
2902                 re_search = true;
2903                 goto again;
2904         }
2905 out_lock:
2906         btrfs_discard_update_discardable(block_group);
2907         spin_unlock(&ctl->tree_lock);
2908 out:
2909         return ret;
2910 }
2911
2912 void btrfs_dump_free_space(struct btrfs_block_group *block_group,
2913                            u64 bytes)
2914 {
2915         struct btrfs_fs_info *fs_info = block_group->fs_info;
2916         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2917         struct btrfs_free_space *info;
2918         struct rb_node *n;
2919         int count = 0;
2920
2921         /*
2922          * Zoned btrfs does not use free space tree and cluster. Just print
2923          * out the free space after the allocation offset.
2924          */
2925         if (btrfs_is_zoned(fs_info)) {
2926                 btrfs_info(fs_info, "free space %llu active %d",
2927                            block_group->zone_capacity - block_group->alloc_offset,
2928                            test_bit(BLOCK_GROUP_FLAG_ZONE_IS_ACTIVE,
2929                                     &block_group->runtime_flags));
2930                 return;
2931         }
2932
2933         spin_lock(&ctl->tree_lock);
2934         for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
2935                 info = rb_entry(n, struct btrfs_free_space, offset_index);
2936                 if (info->bytes >= bytes && !block_group->ro)
2937                         count++;
2938                 btrfs_crit(fs_info, "entry offset %llu, bytes %llu, bitmap %s",
2939                            info->offset, info->bytes,
2940                        (info->bitmap) ? "yes" : "no");
2941         }
2942         spin_unlock(&ctl->tree_lock);
2943         btrfs_info(fs_info, "block group has cluster?: %s",
2944                list_empty(&block_group->cluster_list) ? "no" : "yes");
2945         btrfs_info(fs_info,
2946                    "%d free space entries at or bigger than %llu bytes",
2947                    count, bytes);
2948 }
2949
2950 void btrfs_init_free_space_ctl(struct btrfs_block_group *block_group,
2951                                struct btrfs_free_space_ctl *ctl)
2952 {
2953         struct btrfs_fs_info *fs_info = block_group->fs_info;
2954
2955         spin_lock_init(&ctl->tree_lock);
2956         ctl->unit = fs_info->sectorsize;
2957         ctl->start = block_group->start;
2958         ctl->block_group = block_group;
2959         ctl->op = &free_space_op;
2960         ctl->free_space_bytes = RB_ROOT_CACHED;
2961         INIT_LIST_HEAD(&ctl->trimming_ranges);
2962         mutex_init(&ctl->cache_writeout_mutex);
2963
2964         /*
2965          * we only want to have 32k of ram per block group for keeping
2966          * track of free space, and if we pass 1/2 of that we want to
2967          * start converting things over to using bitmaps
2968          */
2969         ctl->extents_thresh = (SZ_32K / 2) / sizeof(struct btrfs_free_space);
2970 }
2971
2972 /*
2973  * for a given cluster, put all of its extents back into the free
2974  * space cache.  If the block group passed doesn't match the block group
2975  * pointed to by the cluster, someone else raced in and freed the
2976  * cluster already.  In that case, we just return without changing anything
2977  */
2978 static void __btrfs_return_cluster_to_free_space(
2979                              struct btrfs_block_group *block_group,
2980                              struct btrfs_free_cluster *cluster)
2981 {
2982         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2983         struct rb_node *node;
2984
2985         lockdep_assert_held(&ctl->tree_lock);
2986
2987         spin_lock(&cluster->lock);
2988         if (cluster->block_group != block_group) {
2989                 spin_unlock(&cluster->lock);
2990                 return;
2991         }
2992
2993         cluster->block_group = NULL;
2994         cluster->window_start = 0;
2995         list_del_init(&cluster->block_group_list);
2996
2997         node = rb_first(&cluster->root);
2998         while (node) {
2999                 struct btrfs_free_space *entry;
3000
3001                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
3002                 node = rb_next(&entry->offset_index);
3003                 rb_erase(&entry->offset_index, &cluster->root);
3004                 RB_CLEAR_NODE(&entry->offset_index);
3005
3006                 if (!entry->bitmap) {
3007                         /* Merging treats extents as if they were new */
3008                         if (!btrfs_free_space_trimmed(entry)) {
3009                                 ctl->discardable_extents[BTRFS_STAT_CURR]--;
3010                                 ctl->discardable_bytes[BTRFS_STAT_CURR] -=
3011                                         entry->bytes;
3012                         }
3013
3014                         try_merge_free_space(ctl, entry, false);
3015                         steal_from_bitmap(ctl, entry, false);
3016
3017                         /* As we insert directly, update these statistics */
3018                         if (!btrfs_free_space_trimmed(entry)) {
3019                                 ctl->discardable_extents[BTRFS_STAT_CURR]++;
3020                                 ctl->discardable_bytes[BTRFS_STAT_CURR] +=
3021                                         entry->bytes;
3022                         }
3023                 }
3024                 tree_insert_offset(ctl, NULL, entry);
3025                 rb_add_cached(&entry->bytes_index, &ctl->free_space_bytes,
3026                               entry_less);
3027         }
3028         cluster->root = RB_ROOT;
3029         spin_unlock(&cluster->lock);
3030         btrfs_put_block_group(block_group);
3031 }
3032
3033 void btrfs_remove_free_space_cache(struct btrfs_block_group *block_group)
3034 {
3035         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3036         struct btrfs_free_cluster *cluster;
3037         struct list_head *head;
3038
3039         spin_lock(&ctl->tree_lock);
3040         while ((head = block_group->cluster_list.next) !=
3041                &block_group->cluster_list) {
3042                 cluster = list_entry(head, struct btrfs_free_cluster,
3043                                      block_group_list);
3044
3045                 WARN_ON(cluster->block_group != block_group);
3046                 __btrfs_return_cluster_to_free_space(block_group, cluster);
3047
3048                 cond_resched_lock(&ctl->tree_lock);
3049         }
3050         __btrfs_remove_free_space_cache(ctl);
3051         btrfs_discard_update_discardable(block_group);
3052         spin_unlock(&ctl->tree_lock);
3053
3054 }
3055
3056 /*
3057  * Walk @block_group's free space rb_tree to determine if everything is trimmed.
3058  */
3059 bool btrfs_is_free_space_trimmed(struct btrfs_block_group *block_group)
3060 {
3061         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3062         struct btrfs_free_space *info;
3063         struct rb_node *node;
3064         bool ret = true;
3065
3066         spin_lock(&ctl->tree_lock);
3067         node = rb_first(&ctl->free_space_offset);
3068
3069         while (node) {
3070                 info = rb_entry(node, struct btrfs_free_space, offset_index);
3071
3072                 if (!btrfs_free_space_trimmed(info)) {
3073                         ret = false;
3074                         break;
3075                 }
3076
3077                 node = rb_next(node);
3078         }
3079
3080         spin_unlock(&ctl->tree_lock);
3081         return ret;
3082 }
3083
3084 u64 btrfs_find_space_for_alloc(struct btrfs_block_group *block_group,
3085                                u64 offset, u64 bytes, u64 empty_size,
3086                                u64 *max_extent_size)
3087 {
3088         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3089         struct btrfs_discard_ctl *discard_ctl =
3090                                         &block_group->fs_info->discard_ctl;
3091         struct btrfs_free_space *entry = NULL;
3092         u64 bytes_search = bytes + empty_size;
3093         u64 ret = 0;
3094         u64 align_gap = 0;
3095         u64 align_gap_len = 0;
3096         enum btrfs_trim_state align_gap_trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
3097         bool use_bytes_index = (offset == block_group->start);
3098
3099         ASSERT(!btrfs_is_zoned(block_group->fs_info));
3100
3101         spin_lock(&ctl->tree_lock);
3102         entry = find_free_space(ctl, &offset, &bytes_search,
3103                                 block_group->full_stripe_len, max_extent_size,
3104                                 use_bytes_index);
3105         if (!entry)
3106                 goto out;
3107
3108         ret = offset;
3109         if (entry->bitmap) {
3110                 bitmap_clear_bits(ctl, entry, offset, bytes, true);
3111
3112                 if (!btrfs_free_space_trimmed(entry))
3113                         atomic64_add(bytes, &discard_ctl->discard_bytes_saved);
3114
3115                 if (!entry->bytes)
3116                         free_bitmap(ctl, entry);
3117         } else {
3118                 unlink_free_space(ctl, entry, true);
3119                 align_gap_len = offset - entry->offset;
3120                 align_gap = entry->offset;
3121                 align_gap_trim_state = entry->trim_state;
3122
3123                 if (!btrfs_free_space_trimmed(entry))
3124                         atomic64_add(bytes, &discard_ctl->discard_bytes_saved);
3125
3126                 entry->offset = offset + bytes;
3127                 WARN_ON(entry->bytes < bytes + align_gap_len);
3128
3129                 entry->bytes -= bytes + align_gap_len;
3130                 if (!entry->bytes)
3131                         kmem_cache_free(btrfs_free_space_cachep, entry);
3132                 else
3133                         link_free_space(ctl, entry);
3134         }
3135 out:
3136         btrfs_discard_update_discardable(block_group);
3137         spin_unlock(&ctl->tree_lock);
3138
3139         if (align_gap_len)
3140                 __btrfs_add_free_space(block_group, align_gap, align_gap_len,
3141                                        align_gap_trim_state);
3142         return ret;
3143 }
3144
3145 /*
3146  * given a cluster, put all of its extents back into the free space
3147  * cache.  If a block group is passed, this function will only free
3148  * a cluster that belongs to the passed block group.
3149  *
3150  * Otherwise, it'll get a reference on the block group pointed to by the
3151  * cluster and remove the cluster from it.
3152  */
3153 void btrfs_return_cluster_to_free_space(
3154                                struct btrfs_block_group *block_group,
3155                                struct btrfs_free_cluster *cluster)
3156 {
3157         struct btrfs_free_space_ctl *ctl;
3158
3159         /* first, get a safe pointer to the block group */
3160         spin_lock(&cluster->lock);
3161         if (!block_group) {
3162                 block_group = cluster->block_group;
3163                 if (!block_group) {
3164                         spin_unlock(&cluster->lock);
3165                         return;
3166                 }
3167         } else if (cluster->block_group != block_group) {
3168                 /* someone else has already freed it don't redo their work */
3169                 spin_unlock(&cluster->lock);
3170                 return;
3171         }
3172         btrfs_get_block_group(block_group);
3173         spin_unlock(&cluster->lock);
3174
3175         ctl = block_group->free_space_ctl;
3176
3177         /* now return any extents the cluster had on it */
3178         spin_lock(&ctl->tree_lock);
3179         __btrfs_return_cluster_to_free_space(block_group, cluster);
3180         spin_unlock(&ctl->tree_lock);
3181
3182         btrfs_discard_queue_work(&block_group->fs_info->discard_ctl, block_group);
3183
3184         /* finally drop our ref */
3185         btrfs_put_block_group(block_group);
3186 }
3187
3188 static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group *block_group,
3189                                    struct btrfs_free_cluster *cluster,
3190                                    struct btrfs_free_space *entry,
3191                                    u64 bytes, u64 min_start,
3192                                    u64 *max_extent_size)
3193 {
3194         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3195         int err;
3196         u64 search_start = cluster->window_start;
3197         u64 search_bytes = bytes;
3198         u64 ret = 0;
3199
3200         search_start = min_start;
3201         search_bytes = bytes;
3202
3203         err = search_bitmap(ctl, entry, &search_start, &search_bytes, true);
3204         if (err) {
3205                 *max_extent_size = max(get_max_extent_size(entry),
3206                                        *max_extent_size);
3207                 return 0;
3208         }
3209
3210         ret = search_start;
3211         bitmap_clear_bits(ctl, entry, ret, bytes, false);
3212
3213         return ret;
3214 }
3215
3216 /*
3217  * given a cluster, try to allocate 'bytes' from it, returns 0
3218  * if it couldn't find anything suitably large, or a logical disk offset
3219  * if things worked out
3220  */
3221 u64 btrfs_alloc_from_cluster(struct btrfs_block_group *block_group,
3222                              struct btrfs_free_cluster *cluster, u64 bytes,
3223                              u64 min_start, u64 *max_extent_size)
3224 {
3225         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3226         struct btrfs_discard_ctl *discard_ctl =
3227                                         &block_group->fs_info->discard_ctl;
3228         struct btrfs_free_space *entry = NULL;
3229         struct rb_node *node;
3230         u64 ret = 0;
3231
3232         ASSERT(!btrfs_is_zoned(block_group->fs_info));
3233
3234         spin_lock(&cluster->lock);
3235         if (bytes > cluster->max_size)
3236                 goto out;
3237
3238         if (cluster->block_group != block_group)
3239                 goto out;
3240
3241         node = rb_first(&cluster->root);
3242         if (!node)
3243                 goto out;
3244
3245         entry = rb_entry(node, struct btrfs_free_space, offset_index);
3246         while (1) {
3247                 if (entry->bytes < bytes)
3248                         *max_extent_size = max(get_max_extent_size(entry),
3249                                                *max_extent_size);
3250
3251                 if (entry->bytes < bytes ||
3252                     (!entry->bitmap && entry->offset < min_start)) {
3253                         node = rb_next(&entry->offset_index);
3254                         if (!node)
3255                                 break;
3256                         entry = rb_entry(node, struct btrfs_free_space,
3257                                          offset_index);
3258                         continue;
3259                 }
3260
3261                 if (entry->bitmap) {
3262                         ret = btrfs_alloc_from_bitmap(block_group,
3263                                                       cluster, entry, bytes,
3264                                                       cluster->window_start,
3265                                                       max_extent_size);
3266                         if (ret == 0) {
3267                                 node = rb_next(&entry->offset_index);
3268                                 if (!node)
3269                                         break;
3270                                 entry = rb_entry(node, struct btrfs_free_space,
3271                                                  offset_index);
3272                                 continue;
3273                         }
3274                         cluster->window_start += bytes;
3275                 } else {
3276                         ret = entry->offset;
3277
3278                         entry->offset += bytes;
3279                         entry->bytes -= bytes;
3280                 }
3281
3282                 break;
3283         }
3284 out:
3285         spin_unlock(&cluster->lock);
3286
3287         if (!ret)
3288                 return 0;
3289
3290         spin_lock(&ctl->tree_lock);
3291
3292         if (!btrfs_free_space_trimmed(entry))
3293                 atomic64_add(bytes, &discard_ctl->discard_bytes_saved);
3294
3295         ctl->free_space -= bytes;
3296         if (!entry->bitmap && !btrfs_free_space_trimmed(entry))
3297                 ctl->discardable_bytes[BTRFS_STAT_CURR] -= bytes;
3298
3299         spin_lock(&cluster->lock);
3300         if (entry->bytes == 0) {
3301                 rb_erase(&entry->offset_index, &cluster->root);
3302                 ctl->free_extents--;
3303                 if (entry->bitmap) {
3304                         kmem_cache_free(btrfs_free_space_bitmap_cachep,
3305                                         entry->bitmap);
3306                         ctl->total_bitmaps--;
3307                         recalculate_thresholds(ctl);
3308                 } else if (!btrfs_free_space_trimmed(entry)) {
3309                         ctl->discardable_extents[BTRFS_STAT_CURR]--;
3310                 }
3311                 kmem_cache_free(btrfs_free_space_cachep, entry);
3312         }
3313
3314         spin_unlock(&cluster->lock);
3315         spin_unlock(&ctl->tree_lock);
3316
3317         return ret;
3318 }
3319
3320 static int btrfs_bitmap_cluster(struct btrfs_block_group *block_group,
3321                                 struct btrfs_free_space *entry,
3322                                 struct btrfs_free_cluster *cluster,
3323                                 u64 offset, u64 bytes,
3324                                 u64 cont1_bytes, u64 min_bytes)
3325 {
3326         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3327         unsigned long next_zero;
3328         unsigned long i;
3329         unsigned long want_bits;
3330         unsigned long min_bits;
3331         unsigned long found_bits;
3332         unsigned long max_bits = 0;
3333         unsigned long start = 0;
3334         unsigned long total_found = 0;
3335         int ret;
3336
3337         lockdep_assert_held(&ctl->tree_lock);
3338
3339         i = offset_to_bit(entry->offset, ctl->unit,
3340                           max_t(u64, offset, entry->offset));
3341         want_bits = bytes_to_bits(bytes, ctl->unit);
3342         min_bits = bytes_to_bits(min_bytes, ctl->unit);
3343
3344         /*
3345          * Don't bother looking for a cluster in this bitmap if it's heavily
3346          * fragmented.
3347          */
3348         if (entry->max_extent_size &&
3349             entry->max_extent_size < cont1_bytes)
3350                 return -ENOSPC;
3351 again:
3352         found_bits = 0;
3353         for_each_set_bit_from(i, entry->bitmap, BITS_PER_BITMAP) {
3354                 next_zero = find_next_zero_bit(entry->bitmap,
3355                                                BITS_PER_BITMAP, i);
3356                 if (next_zero - i >= min_bits) {
3357                         found_bits = next_zero - i;
3358                         if (found_bits > max_bits)
3359                                 max_bits = found_bits;
3360                         break;
3361                 }
3362                 if (next_zero - i > max_bits)
3363                         max_bits = next_zero - i;
3364                 i = next_zero;
3365         }
3366
3367         if (!found_bits) {
3368                 entry->max_extent_size = (u64)max_bits * ctl->unit;
3369                 return -ENOSPC;
3370         }
3371
3372         if (!total_found) {
3373                 start = i;
3374                 cluster->max_size = 0;
3375         }
3376
3377         total_found += found_bits;
3378
3379         if (cluster->max_size < found_bits * ctl->unit)
3380                 cluster->max_size = found_bits * ctl->unit;
3381
3382         if (total_found < want_bits || cluster->max_size < cont1_bytes) {
3383                 i = next_zero + 1;
3384                 goto again;
3385         }
3386
3387         cluster->window_start = start * ctl->unit + entry->offset;
3388         rb_erase(&entry->offset_index, &ctl->free_space_offset);
3389         rb_erase_cached(&entry->bytes_index, &ctl->free_space_bytes);
3390
3391         /*
3392          * We need to know if we're currently on the normal space index when we
3393          * manipulate the bitmap so that we know we need to remove and re-insert
3394          * it into the space_index tree.  Clear the bytes_index node here so the
3395          * bitmap manipulation helpers know not to mess with the space_index
3396          * until this bitmap entry is added back into the normal cache.
3397          */
3398         RB_CLEAR_NODE(&entry->bytes_index);
3399
3400         ret = tree_insert_offset(ctl, cluster, entry);
3401         ASSERT(!ret); /* -EEXIST; Logic error */
3402
3403         trace_btrfs_setup_cluster(block_group, cluster,
3404                                   total_found * ctl->unit, 1);
3405         return 0;
3406 }
3407
3408 /*
3409  * This searches the block group for just extents to fill the cluster with.
3410  * Try to find a cluster with at least bytes total bytes, at least one
3411  * extent of cont1_bytes, and other clusters of at least min_bytes.
3412  */
3413 static noinline int
3414 setup_cluster_no_bitmap(struct btrfs_block_group *block_group,
3415                         struct btrfs_free_cluster *cluster,
3416                         struct list_head *bitmaps, u64 offset, u64 bytes,
3417                         u64 cont1_bytes, u64 min_bytes)
3418 {
3419         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3420         struct btrfs_free_space *first = NULL;
3421         struct btrfs_free_space *entry = NULL;
3422         struct btrfs_free_space *last;
3423         struct rb_node *node;
3424         u64 window_free;
3425         u64 max_extent;
3426         u64 total_size = 0;
3427
3428         lockdep_assert_held(&ctl->tree_lock);
3429
3430         entry = tree_search_offset(ctl, offset, 0, 1);
3431         if (!entry)
3432                 return -ENOSPC;
3433
3434         /*
3435          * We don't want bitmaps, so just move along until we find a normal
3436          * extent entry.
3437          */
3438         while (entry->bitmap || entry->bytes < min_bytes) {
3439                 if (entry->bitmap && list_empty(&entry->list))
3440                         list_add_tail(&entry->list, bitmaps);
3441                 node = rb_next(&entry->offset_index);
3442                 if (!node)
3443                         return -ENOSPC;
3444                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
3445         }
3446
3447         window_free = entry->bytes;
3448         max_extent = entry->bytes;
3449         first = entry;
3450         last = entry;
3451
3452         for (node = rb_next(&entry->offset_index); node;
3453              node = rb_next(&entry->offset_index)) {
3454                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
3455
3456                 if (entry->bitmap) {
3457                         if (list_empty(&entry->list))
3458                                 list_add_tail(&entry->list, bitmaps);
3459                         continue;
3460                 }
3461
3462                 if (entry->bytes < min_bytes)
3463                         continue;
3464
3465                 last = entry;
3466                 window_free += entry->bytes;
3467                 if (entry->bytes > max_extent)
3468                         max_extent = entry->bytes;
3469         }
3470
3471         if (window_free < bytes || max_extent < cont1_bytes)
3472                 return -ENOSPC;
3473
3474         cluster->window_start = first->offset;
3475
3476         node = &first->offset_index;
3477
3478         /*
3479          * now we've found our entries, pull them out of the free space
3480          * cache and put them into the cluster rbtree
3481          */
3482         do {
3483                 int ret;
3484
3485                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
3486                 node = rb_next(&entry->offset_index);
3487                 if (entry->bitmap || entry->bytes < min_bytes)
3488                         continue;
3489
3490                 rb_erase(&entry->offset_index, &ctl->free_space_offset);
3491                 rb_erase_cached(&entry->bytes_index, &ctl->free_space_bytes);
3492                 ret = tree_insert_offset(ctl, cluster, entry);
3493                 total_size += entry->bytes;
3494                 ASSERT(!ret); /* -EEXIST; Logic error */
3495         } while (node && entry != last);
3496
3497         cluster->max_size = max_extent;
3498         trace_btrfs_setup_cluster(block_group, cluster, total_size, 0);
3499         return 0;
3500 }
3501
3502 /*
3503  * This specifically looks for bitmaps that may work in the cluster, we assume
3504  * that we have already failed to find extents that will work.
3505  */
3506 static noinline int
3507 setup_cluster_bitmap(struct btrfs_block_group *block_group,
3508                      struct btrfs_free_cluster *cluster,
3509                      struct list_head *bitmaps, u64 offset, u64 bytes,
3510                      u64 cont1_bytes, u64 min_bytes)
3511 {
3512         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3513         struct btrfs_free_space *entry = NULL;
3514         int ret = -ENOSPC;
3515         u64 bitmap_offset = offset_to_bitmap(ctl, offset);
3516
3517         if (ctl->total_bitmaps == 0)
3518                 return -ENOSPC;
3519
3520         /*
3521          * The bitmap that covers offset won't be in the list unless offset
3522          * is just its start offset.
3523          */
3524         if (!list_empty(bitmaps))
3525                 entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
3526
3527         if (!entry || entry->offset != bitmap_offset) {
3528                 entry = tree_search_offset(ctl, bitmap_offset, 1, 0);
3529                 if (entry && list_empty(&entry->list))
3530                         list_add(&entry->list, bitmaps);
3531         }
3532
3533         list_for_each_entry(entry, bitmaps, list) {
3534                 if (entry->bytes < bytes)
3535                         continue;
3536                 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
3537                                            bytes, cont1_bytes, min_bytes);
3538                 if (!ret)
3539                         return 0;
3540         }
3541
3542         /*
3543          * The bitmaps list has all the bitmaps that record free space
3544          * starting after offset, so no more search is required.
3545          */
3546         return -ENOSPC;
3547 }
3548
3549 /*
3550  * here we try to find a cluster of blocks in a block group.  The goal
3551  * is to find at least bytes+empty_size.
3552  * We might not find them all in one contiguous area.
3553  *
3554  * returns zero and sets up cluster if things worked out, otherwise
3555  * it returns -enospc
3556  */
3557 int btrfs_find_space_cluster(struct btrfs_block_group *block_group,
3558                              struct btrfs_free_cluster *cluster,
3559                              u64 offset, u64 bytes, u64 empty_size)
3560 {
3561         struct btrfs_fs_info *fs_info = block_group->fs_info;
3562         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3563         struct btrfs_free_space *entry, *tmp;
3564         LIST_HEAD(bitmaps);
3565         u64 min_bytes;
3566         u64 cont1_bytes;
3567         int ret;
3568
3569         /*
3570          * Choose the minimum extent size we'll require for this
3571          * cluster.  For SSD_SPREAD, don't allow any fragmentation.
3572          * For metadata, allow allocates with smaller extents.  For
3573          * data, keep it dense.
3574          */
3575         if (btrfs_test_opt(fs_info, SSD_SPREAD)) {
3576                 cont1_bytes = bytes + empty_size;
3577                 min_bytes = cont1_bytes;
3578         } else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
3579                 cont1_bytes = bytes;
3580                 min_bytes = fs_info->sectorsize;
3581         } else {
3582                 cont1_bytes = max(bytes, (bytes + empty_size) >> 2);
3583                 min_bytes = fs_info->sectorsize;
3584         }
3585
3586         spin_lock(&ctl->tree_lock);
3587
3588         /*
3589          * If we know we don't have enough space to make a cluster don't even
3590          * bother doing all the work to try and find one.
3591          */
3592         if (ctl->free_space < bytes) {
3593                 spin_unlock(&ctl->tree_lock);
3594                 return -ENOSPC;
3595         }
3596
3597         spin_lock(&cluster->lock);
3598
3599         /* someone already found a cluster, hooray */
3600         if (cluster->block_group) {
3601                 ret = 0;
3602                 goto out;
3603         }
3604
3605         trace_btrfs_find_cluster(block_group, offset, bytes, empty_size,
3606                                  min_bytes);
3607
3608         ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
3609                                       bytes + empty_size,
3610                                       cont1_bytes, min_bytes);
3611         if (ret)
3612                 ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
3613                                            offset, bytes + empty_size,
3614                                            cont1_bytes, min_bytes);
3615
3616         /* Clear our temporary list */
3617         list_for_each_entry_safe(entry, tmp, &bitmaps, list)
3618                 list_del_init(&entry->list);
3619
3620         if (!ret) {
3621                 btrfs_get_block_group(block_group);
3622                 list_add_tail(&cluster->block_group_list,
3623                               &block_group->cluster_list);
3624                 cluster->block_group = block_group;
3625         } else {
3626                 trace_btrfs_failed_cluster_setup(block_group);
3627         }
3628 out:
3629         spin_unlock(&cluster->lock);
3630         spin_unlock(&ctl->tree_lock);
3631
3632         return ret;
3633 }
3634
3635 /*
3636  * simple code to zero out a cluster
3637  */
3638 void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
3639 {
3640         spin_lock_init(&cluster->lock);
3641         spin_lock_init(&cluster->refill_lock);
3642         cluster->root = RB_ROOT;
3643         cluster->max_size = 0;
3644         cluster->fragmented = false;
3645         INIT_LIST_HEAD(&cluster->block_group_list);
3646         cluster->block_group = NULL;
3647 }
3648
3649 static int do_trimming(struct btrfs_block_group *block_group,
3650                        u64 *total_trimmed, u64 start, u64 bytes,
3651                        u64 reserved_start, u64 reserved_bytes,
3652                        enum btrfs_trim_state reserved_trim_state,
3653                        struct btrfs_trim_range *trim_entry)
3654 {
3655         struct btrfs_space_info *space_info = block_group->space_info;
3656         struct btrfs_fs_info *fs_info = block_group->fs_info;
3657         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3658         int ret;
3659         int update = 0;
3660         const u64 end = start + bytes;
3661         const u64 reserved_end = reserved_start + reserved_bytes;
3662         enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
3663         u64 trimmed = 0;
3664
3665         spin_lock(&space_info->lock);
3666         spin_lock(&block_group->lock);
3667         if (!block_group->ro) {
3668                 block_group->reserved += reserved_bytes;
3669                 space_info->bytes_reserved += reserved_bytes;
3670                 update = 1;
3671         }
3672         spin_unlock(&block_group->lock);
3673         spin_unlock(&space_info->lock);
3674
3675         ret = btrfs_discard_extent(fs_info, start, bytes, &trimmed);
3676         if (!ret) {
3677                 *total_trimmed += trimmed;
3678                 trim_state = BTRFS_TRIM_STATE_TRIMMED;
3679         }
3680
3681         mutex_lock(&ctl->cache_writeout_mutex);
3682         if (reserved_start < start)
3683                 __btrfs_add_free_space(block_group, reserved_start,
3684                                        start - reserved_start,
3685                                        reserved_trim_state);
3686         if (end < reserved_end)
3687                 __btrfs_add_free_space(block_group, end, reserved_end - end,
3688                                        reserved_trim_state);
3689         __btrfs_add_free_space(block_group, start, bytes, trim_state);
3690         list_del(&trim_entry->list);
3691         mutex_unlock(&ctl->cache_writeout_mutex);
3692
3693         if (update) {
3694                 spin_lock(&space_info->lock);
3695                 spin_lock(&block_group->lock);
3696                 if (block_group->ro)
3697                         space_info->bytes_readonly += reserved_bytes;
3698                 block_group->reserved -= reserved_bytes;
3699                 space_info->bytes_reserved -= reserved_bytes;
3700                 spin_unlock(&block_group->lock);
3701                 spin_unlock(&space_info->lock);
3702         }
3703
3704         return ret;
3705 }
3706
3707 /*
3708  * If @async is set, then we will trim 1 region and return.
3709  */
3710 static int trim_no_bitmap(struct btrfs_block_group *block_group,
3711                           u64 *total_trimmed, u64 start, u64 end, u64 minlen,
3712                           bool async)
3713 {
3714         struct btrfs_discard_ctl *discard_ctl =
3715                                         &block_group->fs_info->discard_ctl;
3716         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3717         struct btrfs_free_space *entry;
3718         struct rb_node *node;
3719         int ret = 0;
3720         u64 extent_start;
3721         u64 extent_bytes;
3722         enum btrfs_trim_state extent_trim_state;
3723         u64 bytes;
3724         const u64 max_discard_size = READ_ONCE(discard_ctl->max_discard_size);
3725
3726         while (start < end) {
3727                 struct btrfs_trim_range trim_entry;
3728
3729                 mutex_lock(&ctl->cache_writeout_mutex);
3730                 spin_lock(&ctl->tree_lock);
3731
3732                 if (ctl->free_space < minlen)
3733                         goto out_unlock;
3734
3735                 entry = tree_search_offset(ctl, start, 0, 1);
3736                 if (!entry)
3737                         goto out_unlock;
3738
3739                 /* Skip bitmaps and if async, already trimmed entries */
3740                 while (entry->bitmap ||
3741                        (async && btrfs_free_space_trimmed(entry))) {
3742                         node = rb_next(&entry->offset_index);
3743                         if (!node)
3744                                 goto out_unlock;
3745                         entry = rb_entry(node, struct btrfs_free_space,
3746                                          offset_index);
3747                 }
3748
3749                 if (entry->offset >= end)
3750                         goto out_unlock;
3751
3752                 extent_start = entry->offset;
3753                 extent_bytes = entry->bytes;
3754                 extent_trim_state = entry->trim_state;
3755                 if (async) {
3756                         start = entry->offset;
3757                         bytes = entry->bytes;
3758                         if (bytes < minlen) {
3759                                 spin_unlock(&ctl->tree_lock);
3760                                 mutex_unlock(&ctl->cache_writeout_mutex);
3761                                 goto next;
3762                         }
3763                         unlink_free_space(ctl, entry, true);
3764                         /*
3765                          * Let bytes = BTRFS_MAX_DISCARD_SIZE + X.
3766                          * If X < BTRFS_ASYNC_DISCARD_MIN_FILTER, we won't trim
3767                          * X when we come back around.  So trim it now.
3768                          */
3769                         if (max_discard_size &&
3770                             bytes >= (max_discard_size +
3771                                       BTRFS_ASYNC_DISCARD_MIN_FILTER)) {
3772                                 bytes = max_discard_size;
3773                                 extent_bytes = max_discard_size;
3774                                 entry->offset += max_discard_size;
3775                                 entry->bytes -= max_discard_size;
3776                                 link_free_space(ctl, entry);
3777                         } else {
3778                                 kmem_cache_free(btrfs_free_space_cachep, entry);
3779                         }
3780                 } else {
3781                         start = max(start, extent_start);
3782                         bytes = min(extent_start + extent_bytes, end) - start;
3783                         if (bytes < minlen) {
3784                                 spin_unlock(&ctl->tree_lock);
3785                                 mutex_unlock(&ctl->cache_writeout_mutex);
3786                                 goto next;
3787                         }
3788
3789                         unlink_free_space(ctl, entry, true);
3790                         kmem_cache_free(btrfs_free_space_cachep, entry);
3791                 }
3792
3793                 spin_unlock(&ctl->tree_lock);
3794                 trim_entry.start = extent_start;
3795                 trim_entry.bytes = extent_bytes;
3796                 list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
3797                 mutex_unlock(&ctl->cache_writeout_mutex);
3798
3799                 ret = do_trimming(block_group, total_trimmed, start, bytes,
3800                                   extent_start, extent_bytes, extent_trim_state,
3801                                   &trim_entry);
3802                 if (ret) {
3803                         block_group->discard_cursor = start + bytes;
3804                         break;
3805                 }
3806 next:
3807                 start += bytes;
3808                 block_group->discard_cursor = start;
3809                 if (async && *total_trimmed)
3810                         break;
3811
3812                 if (fatal_signal_pending(current)) {
3813                         ret = -ERESTARTSYS;
3814                         break;
3815                 }
3816
3817                 cond_resched();
3818         }
3819
3820         return ret;
3821
3822 out_unlock:
3823         block_group->discard_cursor = btrfs_block_group_end(block_group);
3824         spin_unlock(&ctl->tree_lock);
3825         mutex_unlock(&ctl->cache_writeout_mutex);
3826
3827         return ret;
3828 }
3829
3830 /*
3831  * If we break out of trimming a bitmap prematurely, we should reset the
3832  * trimming bit.  In a rather contrieved case, it's possible to race here so
3833  * reset the state to BTRFS_TRIM_STATE_UNTRIMMED.
3834  *
3835  * start = start of bitmap
3836  * end = near end of bitmap
3837  *
3838  * Thread 1:                    Thread 2:
3839  * trim_bitmaps(start)
3840  *                              trim_bitmaps(end)
3841  *                              end_trimming_bitmap()
3842  * reset_trimming_bitmap()
3843  */
3844 static void reset_trimming_bitmap(struct btrfs_free_space_ctl *ctl, u64 offset)
3845 {
3846         struct btrfs_free_space *entry;
3847
3848         spin_lock(&ctl->tree_lock);
3849         entry = tree_search_offset(ctl, offset, 1, 0);
3850         if (entry) {
3851                 if (btrfs_free_space_trimmed(entry)) {
3852                         ctl->discardable_extents[BTRFS_STAT_CURR] +=
3853                                 entry->bitmap_extents;
3854                         ctl->discardable_bytes[BTRFS_STAT_CURR] += entry->bytes;
3855                 }
3856                 entry->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
3857         }
3858
3859         spin_unlock(&ctl->tree_lock);
3860 }
3861
3862 static void end_trimming_bitmap(struct btrfs_free_space_ctl *ctl,
3863                                 struct btrfs_free_space *entry)
3864 {
3865         if (btrfs_free_space_trimming_bitmap(entry)) {
3866                 entry->trim_state = BTRFS_TRIM_STATE_TRIMMED;
3867                 ctl->discardable_extents[BTRFS_STAT_CURR] -=
3868                         entry->bitmap_extents;
3869                 ctl->discardable_bytes[BTRFS_STAT_CURR] -= entry->bytes;
3870         }
3871 }
3872
3873 /*
3874  * If @async is set, then we will trim 1 region and return.
3875  */
3876 static int trim_bitmaps(struct btrfs_block_group *block_group,
3877                         u64 *total_trimmed, u64 start, u64 end, u64 minlen,
3878                         u64 maxlen, bool async)
3879 {
3880         struct btrfs_discard_ctl *discard_ctl =
3881                                         &block_group->fs_info->discard_ctl;
3882         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3883         struct btrfs_free_space *entry;
3884         int ret = 0;
3885         int ret2;
3886         u64 bytes;
3887         u64 offset = offset_to_bitmap(ctl, start);
3888         const u64 max_discard_size = READ_ONCE(discard_ctl->max_discard_size);
3889
3890         while (offset < end) {
3891                 bool next_bitmap = false;
3892                 struct btrfs_trim_range trim_entry;
3893
3894                 mutex_lock(&ctl->cache_writeout_mutex);
3895                 spin_lock(&ctl->tree_lock);
3896
3897                 if (ctl->free_space < minlen) {
3898                         block_group->discard_cursor =
3899                                 btrfs_block_group_end(block_group);
3900                         spin_unlock(&ctl->tree_lock);
3901                         mutex_unlock(&ctl->cache_writeout_mutex);
3902                         break;
3903                 }
3904
3905                 entry = tree_search_offset(ctl, offset, 1, 0);
3906                 /*
3907                  * Bitmaps are marked trimmed lossily now to prevent constant
3908                  * discarding of the same bitmap (the reason why we are bound
3909                  * by the filters).  So, retrim the block group bitmaps when we
3910                  * are preparing to punt to the unused_bgs list.  This uses
3911                  * @minlen to determine if we are in BTRFS_DISCARD_INDEX_UNUSED
3912                  * which is the only discard index which sets minlen to 0.
3913                  */
3914                 if (!entry || (async && minlen && start == offset &&
3915                                btrfs_free_space_trimmed(entry))) {
3916                         spin_unlock(&ctl->tree_lock);
3917                         mutex_unlock(&ctl->cache_writeout_mutex);
3918                         next_bitmap = true;
3919                         goto next;
3920                 }
3921
3922                 /*
3923                  * Async discard bitmap trimming begins at by setting the start
3924                  * to be key.objectid and the offset_to_bitmap() aligns to the
3925                  * start of the bitmap.  This lets us know we are fully
3926                  * scanning the bitmap rather than only some portion of it.
3927                  */
3928                 if (start == offset)
3929                         entry->trim_state = BTRFS_TRIM_STATE_TRIMMING;
3930
3931                 bytes = minlen;
3932                 ret2 = search_bitmap(ctl, entry, &start, &bytes, false);
3933                 if (ret2 || start >= end) {
3934                         /*
3935                          * We lossily consider a bitmap trimmed if we only skip
3936                          * over regions <= BTRFS_ASYNC_DISCARD_MIN_FILTER.
3937                          */
3938                         if (ret2 && minlen <= BTRFS_ASYNC_DISCARD_MIN_FILTER)
3939                                 end_trimming_bitmap(ctl, entry);
3940                         else
3941                                 entry->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
3942                         spin_unlock(&ctl->tree_lock);
3943                         mutex_unlock(&ctl->cache_writeout_mutex);
3944                         next_bitmap = true;
3945                         goto next;
3946                 }
3947
3948                 /*
3949                  * We already trimmed a region, but are using the locking above
3950                  * to reset the trim_state.
3951                  */
3952                 if (async && *total_trimmed) {
3953                         spin_unlock(&ctl->tree_lock);
3954                         mutex_unlock(&ctl->cache_writeout_mutex);
3955                         goto out;
3956                 }
3957
3958                 bytes = min(bytes, end - start);
3959                 if (bytes < minlen || (async && maxlen && bytes > maxlen)) {
3960                         spin_unlock(&ctl->tree_lock);
3961                         mutex_unlock(&ctl->cache_writeout_mutex);
3962                         goto next;
3963                 }
3964
3965                 /*
3966                  * Let bytes = BTRFS_MAX_DISCARD_SIZE + X.
3967                  * If X < @minlen, we won't trim X when we come back around.
3968                  * So trim it now.  We differ here from trimming extents as we
3969                  * don't keep individual state per bit.
3970                  */
3971                 if (async &&
3972                     max_discard_size &&
3973                     bytes > (max_discard_size + minlen))
3974                         bytes = max_discard_size;
3975
3976                 bitmap_clear_bits(ctl, entry, start, bytes, true);
3977                 if (entry->bytes == 0)
3978                         free_bitmap(ctl, entry);
3979
3980                 spin_unlock(&ctl->tree_lock);
3981                 trim_entry.start = start;
3982                 trim_entry.bytes = bytes;
3983                 list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
3984                 mutex_unlock(&ctl->cache_writeout_mutex);
3985
3986                 ret = do_trimming(block_group, total_trimmed, start, bytes,
3987                                   start, bytes, 0, &trim_entry);
3988                 if (ret) {
3989                         reset_trimming_bitmap(ctl, offset);
3990                         block_group->discard_cursor =
3991                                 btrfs_block_group_end(block_group);
3992                         break;
3993                 }
3994 next:
3995                 if (next_bitmap) {
3996                         offset += BITS_PER_BITMAP * ctl->unit;
3997                         start = offset;
3998                 } else {
3999                         start += bytes;
4000                 }
4001                 block_group->discard_cursor = start;
4002
4003                 if (fatal_signal_pending(current)) {
4004                         if (start != offset)
4005                                 reset_trimming_bitmap(ctl, offset);
4006                         ret = -ERESTARTSYS;
4007                         break;
4008                 }
4009
4010                 cond_resched();
4011         }
4012
4013         if (offset >= end)
4014                 block_group->discard_cursor = end;
4015
4016 out:
4017         return ret;
4018 }
4019
4020 int btrfs_trim_block_group(struct btrfs_block_group *block_group,
4021                            u64 *trimmed, u64 start, u64 end, u64 minlen)
4022 {
4023         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
4024         int ret;
4025         u64 rem = 0;
4026
4027         ASSERT(!btrfs_is_zoned(block_group->fs_info));
4028
4029         *trimmed = 0;
4030
4031         spin_lock(&block_group->lock);
4032         if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags)) {
4033                 spin_unlock(&block_group->lock);
4034                 return 0;
4035         }
4036         btrfs_freeze_block_group(block_group);
4037         spin_unlock(&block_group->lock);
4038
4039         ret = trim_no_bitmap(block_group, trimmed, start, end, minlen, false);
4040         if (ret)
4041                 goto out;
4042
4043         ret = trim_bitmaps(block_group, trimmed, start, end, minlen, 0, false);
4044         div64_u64_rem(end, BITS_PER_BITMAP * ctl->unit, &rem);
4045         /* If we ended in the middle of a bitmap, reset the trimming flag */
4046         if (rem)
4047                 reset_trimming_bitmap(ctl, offset_to_bitmap(ctl, end));
4048 out:
4049         btrfs_unfreeze_block_group(block_group);
4050         return ret;
4051 }
4052
4053 int btrfs_trim_block_group_extents(struct btrfs_block_group *block_group,
4054                                    u64 *trimmed, u64 start, u64 end, u64 minlen,
4055                                    bool async)
4056 {
4057         int ret;
4058
4059         *trimmed = 0;
4060
4061         spin_lock(&block_group->lock);
4062         if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags)) {
4063                 spin_unlock(&block_group->lock);
4064                 return 0;
4065         }
4066         btrfs_freeze_block_group(block_group);
4067         spin_unlock(&block_group->lock);
4068
4069         ret = trim_no_bitmap(block_group, trimmed, start, end, minlen, async);
4070         btrfs_unfreeze_block_group(block_group);
4071
4072         return ret;
4073 }
4074
4075 int btrfs_trim_block_group_bitmaps(struct btrfs_block_group *block_group,
4076                                    u64 *trimmed, u64 start, u64 end, u64 minlen,
4077                                    u64 maxlen, bool async)
4078 {
4079         int ret;
4080
4081         *trimmed = 0;
4082
4083         spin_lock(&block_group->lock);
4084         if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags)) {
4085                 spin_unlock(&block_group->lock);
4086                 return 0;
4087         }
4088         btrfs_freeze_block_group(block_group);
4089         spin_unlock(&block_group->lock);
4090
4091         ret = trim_bitmaps(block_group, trimmed, start, end, minlen, maxlen,
4092                            async);
4093
4094         btrfs_unfreeze_block_group(block_group);
4095
4096         return ret;
4097 }
4098
4099 bool btrfs_free_space_cache_v1_active(struct btrfs_fs_info *fs_info)
4100 {
4101         return btrfs_super_cache_generation(fs_info->super_copy);
4102 }
4103
4104 static int cleanup_free_space_cache_v1(struct btrfs_fs_info *fs_info,
4105                                        struct btrfs_trans_handle *trans)
4106 {
4107         struct btrfs_block_group *block_group;
4108         struct rb_node *node;
4109         int ret = 0;
4110
4111         btrfs_info(fs_info, "cleaning free space cache v1");
4112
4113         node = rb_first_cached(&fs_info->block_group_cache_tree);
4114         while (node) {
4115                 block_group = rb_entry(node, struct btrfs_block_group, cache_node);
4116                 ret = btrfs_remove_free_space_inode(trans, NULL, block_group);
4117                 if (ret)
4118                         goto out;
4119                 node = rb_next(node);
4120         }
4121 out:
4122         return ret;
4123 }
4124
4125 int btrfs_set_free_space_cache_v1_active(struct btrfs_fs_info *fs_info, bool active)
4126 {
4127         struct btrfs_trans_handle *trans;
4128         int ret;
4129
4130         /*
4131          * update_super_roots will appropriately set or unset
4132          * super_copy->cache_generation based on SPACE_CACHE and
4133          * BTRFS_FS_CLEANUP_SPACE_CACHE_V1. For this reason, we need a
4134          * transaction commit whether we are enabling space cache v1 and don't
4135          * have any other work to do, or are disabling it and removing free
4136          * space inodes.
4137          */
4138         trans = btrfs_start_transaction(fs_info->tree_root, 0);
4139         if (IS_ERR(trans))
4140                 return PTR_ERR(trans);
4141
4142         if (!active) {
4143                 set_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags);
4144                 ret = cleanup_free_space_cache_v1(fs_info, trans);
4145                 if (ret) {
4146                         btrfs_abort_transaction(trans, ret);
4147                         btrfs_end_transaction(trans);
4148                         goto out;
4149                 }
4150         }
4151
4152         ret = btrfs_commit_transaction(trans);
4153 out:
4154         clear_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags);
4155
4156         return ret;
4157 }
4158
4159 int __init btrfs_free_space_init(void)
4160 {
4161         btrfs_free_space_cachep = KMEM_CACHE(btrfs_free_space, 0);
4162         if (!btrfs_free_space_cachep)
4163                 return -ENOMEM;
4164
4165         btrfs_free_space_bitmap_cachep = kmem_cache_create("btrfs_free_space_bitmap",
4166                                                         PAGE_SIZE, PAGE_SIZE,
4167                                                         0, NULL);
4168         if (!btrfs_free_space_bitmap_cachep) {
4169                 kmem_cache_destroy(btrfs_free_space_cachep);
4170                 return -ENOMEM;
4171         }
4172
4173         return 0;
4174 }
4175
4176 void __cold btrfs_free_space_exit(void)
4177 {
4178         kmem_cache_destroy(btrfs_free_space_cachep);
4179         kmem_cache_destroy(btrfs_free_space_bitmap_cachep);
4180 }
4181
4182 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
4183 /*
4184  * Use this if you need to make a bitmap or extent entry specifically, it
4185  * doesn't do any of the merging that add_free_space does, this acts a lot like
4186  * how the free space cache loading stuff works, so you can get really weird
4187  * configurations.
4188  */
4189 int test_add_free_space_entry(struct btrfs_block_group *cache,
4190                               u64 offset, u64 bytes, bool bitmap)
4191 {
4192         struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
4193         struct btrfs_free_space *info = NULL, *bitmap_info;
4194         void *map = NULL;
4195         enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_TRIMMED;
4196         u64 bytes_added;
4197         int ret;
4198
4199 again:
4200         if (!info) {
4201                 info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
4202                 if (!info)
4203                         return -ENOMEM;
4204         }
4205
4206         if (!bitmap) {
4207                 spin_lock(&ctl->tree_lock);
4208                 info->offset = offset;
4209                 info->bytes = bytes;
4210                 info->max_extent_size = 0;
4211                 ret = link_free_space(ctl, info);
4212                 spin_unlock(&ctl->tree_lock);
4213                 if (ret)
4214                         kmem_cache_free(btrfs_free_space_cachep, info);
4215                 return ret;
4216         }
4217
4218         if (!map) {
4219                 map = kmem_cache_zalloc(btrfs_free_space_bitmap_cachep, GFP_NOFS);
4220                 if (!map) {
4221                         kmem_cache_free(btrfs_free_space_cachep, info);
4222                         return -ENOMEM;
4223                 }
4224         }
4225
4226         spin_lock(&ctl->tree_lock);
4227         bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
4228                                          1, 0);
4229         if (!bitmap_info) {
4230                 info->bitmap = map;
4231                 map = NULL;
4232                 add_new_bitmap(ctl, info, offset);
4233                 bitmap_info = info;
4234                 info = NULL;
4235         }
4236
4237         bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes,
4238                                           trim_state);
4239
4240         bytes -= bytes_added;
4241         offset += bytes_added;
4242         spin_unlock(&ctl->tree_lock);
4243
4244         if (bytes)
4245                 goto again;
4246
4247         if (info)
4248                 kmem_cache_free(btrfs_free_space_cachep, info);
4249         if (map)
4250                 kmem_cache_free(btrfs_free_space_bitmap_cachep, map);
4251         return 0;
4252 }
4253
4254 /*
4255  * Checks to see if the given range is in the free space cache.  This is really
4256  * just used to check the absence of space, so if there is free space in the
4257  * range at all we will return 1.
4258  */
4259 int test_check_exists(struct btrfs_block_group *cache,
4260                       u64 offset, u64 bytes)
4261 {
4262         struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
4263         struct btrfs_free_space *info;
4264         int ret = 0;
4265
4266         spin_lock(&ctl->tree_lock);
4267         info = tree_search_offset(ctl, offset, 0, 0);
4268         if (!info) {
4269                 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
4270                                           1, 0);
4271                 if (!info)
4272                         goto out;
4273         }
4274
4275 have_info:
4276         if (info->bitmap) {
4277                 u64 bit_off, bit_bytes;
4278                 struct rb_node *n;
4279                 struct btrfs_free_space *tmp;
4280
4281                 bit_off = offset;
4282                 bit_bytes = ctl->unit;
4283                 ret = search_bitmap(ctl, info, &bit_off, &bit_bytes, false);
4284                 if (!ret) {
4285                         if (bit_off == offset) {
4286                                 ret = 1;
4287                                 goto out;
4288                         } else if (bit_off > offset &&
4289                                    offset + bytes > bit_off) {
4290                                 ret = 1;
4291                                 goto out;
4292                         }
4293                 }
4294
4295                 n = rb_prev(&info->offset_index);
4296                 while (n) {
4297                         tmp = rb_entry(n, struct btrfs_free_space,
4298                                        offset_index);
4299                         if (tmp->offset + tmp->bytes < offset)
4300                                 break;
4301                         if (offset + bytes < tmp->offset) {
4302                                 n = rb_prev(&tmp->offset_index);
4303                                 continue;
4304                         }
4305                         info = tmp;
4306                         goto have_info;
4307                 }
4308
4309                 n = rb_next(&info->offset_index);
4310                 while (n) {
4311                         tmp = rb_entry(n, struct btrfs_free_space,
4312                                        offset_index);
4313                         if (offset + bytes < tmp->offset)
4314                                 break;
4315                         if (tmp->offset + tmp->bytes < offset) {
4316                                 n = rb_next(&tmp->offset_index);
4317                                 continue;
4318                         }
4319                         info = tmp;
4320                         goto have_info;
4321                 }
4322
4323                 ret = 0;
4324                 goto out;
4325         }
4326
4327         if (info->offset == offset) {
4328                 ret = 1;
4329                 goto out;
4330         }
4331
4332         if (offset > info->offset && offset < info->offset + info->bytes)
4333                 ret = 1;
4334 out:
4335         spin_unlock(&ctl->tree_lock);
4336         return ret;
4337 }
4338 #endif /* CONFIG_BTRFS_FS_RUN_SANITY_TESTS */