fs/btrfs/inode.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/bio.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/file.h>
  23 #include <linux/fs.h>
  24 #include <linux/pagemap.h>
  25 #include <linux/highmem.h>
  26 #include <linux/time.h>
  27 #include <linux/init.h>
  28 #include <linux/string.h>
  29 #include <linux/backing-dev.h>
  30 #include <linux/mpage.h>
  31 #include <linux/swap.h>
  32 #include <linux/writeback.h>
  33 #include <linux/statfs.h>
  34 #include <linux/compat.h>
  35 #include <linux/bit_spinlock.h>
  36 #include <linux/xattr.h>
  37 #include <linux/posix_acl.h>
  38 #include <linux/falloc.h>
  39 #include <linux/slab.h>
  40 #include "compat.h"
  41 #include "ctree.h"
  42 #include "disk-io.h"
  43 #include "transaction.h"
  44 #include "btrfs_inode.h"
  45 #include "ioctl.h"
  46 #include "print-tree.h"
  47 #include "volumes.h"
  48 #include "ordered-data.h"
  49 #include "xattr.h"
  50 #include "tree-log.h"
  51 #include "compression.h"
  52 #include "locking.h"
  53 #include "free-space-cache.h"
  54
  55 struct btrfs_iget_args {
  56         u64 ino;
  57         struct btrfs_root *root;
  58 };
  59
  60 static const struct inode_operations btrfs_dir_inode_operations;
  61 static const struct inode_operations btrfs_symlink_inode_operations;
  62 static const struct inode_operations btrfs_dir_ro_inode_operations;
  63 static const struct inode_operations btrfs_special_inode_operations;
  64 static const struct inode_operations btrfs_file_inode_operations;
  65 static const struct address_space_operations btrfs_aops;
  66 static const struct address_space_operations btrfs_symlink_aops;
  67 static const struct file_operations btrfs_dir_file_operations;
  68 static struct extent_io_ops btrfs_extent_io_ops;
  69
  70 static struct kmem_cache *btrfs_inode_cachep;
  71 struct kmem_cache *btrfs_trans_handle_cachep;
  72 struct kmem_cache *btrfs_transaction_cachep;
  73 struct kmem_cache *btrfs_path_cachep;
  74 struct kmem_cache *btrfs_free_space_cachep;
  75
  76 #define S_SHIFT 12
  77 static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
  78         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
  79         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
  80         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
  81         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
  82         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
  83         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
  84         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
  85 };
  86
  87 static int btrfs_setsize(struct inode *inode, loff_t newsize);
  88 static int btrfs_truncate(struct inode *inode);
  89 static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end);
  90 static noinline int cow_file_range(struct inode *inode,
  91                                    struct page *locked_page,
  92                                    u64 start, u64 end, int *page_started,
  93                                    unsigned long *nr_written, int unlock);
  94
  95 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
  96                                      struct inode *inode,  struct inode *dir)
  97 {
  98         int err;
  99
 100         err = btrfs_init_acl(trans, inode, dir);
 101         if (!err)
 102                 err = btrfs_xattr_security_init(trans, inode, dir);
 103         return err;
 104 }
 105
 106 /*
 107  * this does all the hard work for inserting an inline extent into
 108  * the btree.  The caller should have done a btrfs_drop_extents so that
 109  * no overlapping inline items exist in the btree
 110  */
 111 static noinline int insert_inline_extent(struct btrfs_trans_handle *trans,
 112                                 struct btrfs_root *root, struct inode *inode,
 113                                 u64 start, size_t size, size_t compressed_size,
 114                                 int compress_type,
 115                                 struct page **compressed_pages)
 116 {
 117         struct btrfs_key key;
 118         struct btrfs_path *path;
 119         struct extent_buffer *leaf;
 120         struct page *page = NULL;
 121         char *kaddr;
 122         unsigned long ptr;
 123         struct btrfs_file_extent_item *ei;
 124         int err = 0;
 125         int ret;
 126         size_t cur_size = size;
 127         size_t datasize;
 128         unsigned long offset;
 129
 130         if (compressed_size && compressed_pages)
 131                 cur_size = compressed_size;
 132
 133         path = btrfs_alloc_path();
 134         if (!path)
 135                 return -ENOMEM;
 136
 137         path->leave_spinning = 1;
 138         btrfs_set_trans_block_group(trans, inode);
 139
 140         key.objectid = inode->i_ino;
 141         key.offset = start;
 142         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
 143         datasize = btrfs_file_extent_calc_inline_size(cur_size);
 144
 145         inode_add_bytes(inode, size);
 146         ret = btrfs_insert_empty_item(trans, root, path, &key,
 147                                       datasize);
 148         BUG_ON(ret);
 149         if (ret) {
 150                 err = ret;
 151                 goto fail;
 152         }
 153         leaf = path->nodes[0];
 154         ei = btrfs_item_ptr(leaf, path->slots[0],
 155                             struct btrfs_file_extent_item);
 156         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 157         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 158         btrfs_set_file_extent_encryption(leaf, ei, 0);
 159         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
 160         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
 161         ptr = btrfs_file_extent_inline_start(ei);
 162
 163         if (compress_type != BTRFS_COMPRESS_NONE) {
 164                 struct page *cpage;
 165                 int i = 0;
 166                 while (compressed_size > 0) {
 167                         cpage = compressed_pages[i];
 168                         cur_size = min_t(unsigned long, compressed_size,
 169                                        PAGE_CACHE_SIZE);
 170
 171                         kaddr = kmap_atomic(cpage, KM_USER0);
 172                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
 173                         kunmap_atomic(kaddr, KM_USER0);
 174
 175                         i++;
 176                         ptr += cur_size;
 177                         compressed_size -= cur_size;
 178                 }
 179                 btrfs_set_file_extent_compression(leaf, ei,
 180                                                   compress_type);
 181         } else {
 182                 page = find_get_page(inode->i_mapping,
 183                                      start >> PAGE_CACHE_SHIFT);
 184                 btrfs_set_file_extent_compression(leaf, ei, 0);
 185                 kaddr = kmap_atomic(page, KM_USER0);
 186                 offset = start & (PAGE_CACHE_SIZE - 1);
 187                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
 188                 kunmap_atomic(kaddr, KM_USER0);
 189                 page_cache_release(page);
 190         }
 191         btrfs_mark_buffer_dirty(leaf);
 192         btrfs_free_path(path);
 193
 194         /*
 195          * we're an inline extent, so nobody can
 196          * extend the file past i_size without locking
 197          * a page we already have locked.
 198          *
 199          * We must do any isize and inode updates
 200          * before we unlock the pages.  Otherwise we
 201          * could end up racing with unlink.
 202          */
 203         BTRFS_I(inode)->disk_i_size = inode->i_size;
 204         btrfs_update_inode(trans, root, inode);
 205
 206         return 0;
 207 fail:
 208         btrfs_free_path(path);
 209         return err;
 210 }
 211
 212
 213 /*
 214  * conditionally insert an inline extent into the file.  This
 215  * does the checks required to make sure the data is small enough
 216  * to fit as an inline extent.
 217  */
 218 static noinline int cow_file_range_inline(struct btrfs_trans_handle *trans,
 219                                  struct btrfs_root *root,
 220                                  struct inode *inode, u64 start, u64 end,
 221                                  size_t compressed_size, int compress_type,
 222                                  struct page **compressed_pages)
 223 {
 224         u64 isize = i_size_read(inode);
 225         u64 actual_end = min(end + 1, isize);
 226         u64 inline_len = actual_end - start;
 227         u64 aligned_end = (end + root->sectorsize - 1) &
 228                         ~((u64)root->sectorsize - 1);
 229         u64 hint_byte;
 230         u64 data_len = inline_len;
 231         int ret;
 232
 233         if (compressed_size)
 234                 data_len = compressed_size;
 235
 236         if (start > 0 ||
 237             actual_end >= PAGE_CACHE_SIZE ||
 238             data_len >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
 239             (!compressed_size &&
 240             (actual_end & (root->sectorsize - 1)) == 0) ||
 241             end + 1 < isize ||
 242             data_len > root->fs_info->max_inline) {
 243                 return 1;
 244         }
 245
 246         ret = btrfs_drop_extents(trans, inode, start, aligned_end,
 247                                  &hint_byte, 1);
 248         BUG_ON(ret);
 249
 250         if (isize > actual_end)
 251                 inline_len = min_t(u64, isize, actual_end);
 252         ret = insert_inline_extent(trans, root, inode, start,
 253                                    inline_len, compressed_size,
 254                                    compress_type, compressed_pages);
 255         BUG_ON(ret);
 256         btrfs_delalloc_release_metadata(inode, end + 1 - start);
 257         btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
 258         return 0;
 259 }
 260
 261 struct async_extent {
 262         u64 start;
 263         u64 ram_size;
 264         u64 compressed_size;
 265         struct page **pages;
 266         unsigned long nr_pages;
 267         int compress_type;
 268         struct list_head list;
 269 };
 270
 271 struct async_cow {
 272         struct inode *inode;
 273         struct btrfs_root *root;
 274         struct page *locked_page;
 275         u64 start;
 276         u64 end;
 277         struct list_head extents;
 278         struct btrfs_work work;
 279 };
 280
 281 static noinline int add_async_extent(struct async_cow *cow,
 282                                      u64 start, u64 ram_size,
 283                                      u64 compressed_size,
 284                                      struct page **pages,
 285                                      unsigned long nr_pages,
 286                                      int compress_type)
 287 {
 288         struct async_extent *async_extent;
 289
 290         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
 291         BUG_ON(!async_extent);
 292         async_extent->start = start;
 293         async_extent->ram_size = ram_size;
 294         async_extent->compressed_size = compressed_size;
 295         async_extent->pages = pages;
 296         async_extent->nr_pages = nr_pages;
 297         async_extent->compress_type = compress_type;
 298         list_add_tail(&async_extent->list, &cow->extents);
 299         return 0;
 300 }
 301
 302 /*
 303  * we create compressed extents in two phases.  The first
 304  * phase compresses a range of pages that have already been
 305  * locked (both pages and state bits are locked).
 306  *
 307  * This is done inside an ordered work queue, and the compression
 308  * is spread across many cpus.  The actual IO submission is step
 309  * two, and the ordered work queue takes care of making sure that
 310  * happens in the same order things were put onto the queue by
 311  * writepages and friends.
 312  *
 313  * If this code finds it can't get good compression, it puts an
 314  * entry onto the work queue to write the uncompressed bytes.  This
 315  * makes sure that both compressed inodes and uncompressed inodes
 316  * are written in the same order that pdflush sent them down.
 317  */
 318 static noinline int compress_file_range(struct inode *inode,
 319                                         struct page *locked_page,
 320                                         u64 start, u64 end,
 321                                         struct async_cow *async_cow,
 322                                         int *num_added)
 323 {
 324         struct btrfs_root *root = BTRFS_I(inode)->root;
 325         struct btrfs_trans_handle *trans;
 326         u64 num_bytes;
 327         u64 blocksize = root->sectorsize;
 328         u64 actual_end;
 329         u64 isize = i_size_read(inode);
 330         int ret = 0;
 331         struct page **pages = NULL;
 332         unsigned long nr_pages;
 333         unsigned long nr_pages_ret = 0;
 334         unsigned long total_compressed = 0;
 335         unsigned long total_in = 0;
 336         unsigned long max_compressed = 128 * 1024;
 337         unsigned long max_uncompressed = 128 * 1024;
 338         int i;
 339         int will_compress;
 340         int compress_type = root->fs_info->compress_type;
 341
 342         actual_end = min_t(u64, isize, end + 1);
 343 again:
 344         will_compress = 0;
 345         nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1;
 346         nr_pages = min(nr_pages, (128 * 1024UL) / PAGE_CACHE_SIZE);
 347
 348         /*
 349          * we don't want to send crud past the end of i_size through
 350          * compression, that's just a waste of CPU time.  So, if the
 351          * end of the file is before the start of our current
 352          * requested range of bytes, we bail out to the uncompressed
 353          * cleanup code that can deal with all of this.
 354          *
 355          * It isn't really the fastest way to fix things, but this is a
 356          * very uncommon corner.
 357          */
 358         if (actual_end <= start)
 359                 goto cleanup_and_bail_uncompressed;
 360
 361         total_compressed = actual_end - start;
 362
 363         /* we want to make sure that amount of ram required to uncompress
 364          * an extent is reasonable, so we limit the total size in ram
 365          * of a compressed extent to 128k.  This is a crucial number
 366          * because it also controls how easily we can spread reads across
 367          * cpus for decompression.
 368          *
 369          * We also want to make sure the amount of IO required to do
 370          * a random read is reasonably small, so we limit the size of
 371          * a compressed extent to 128k.
 372          */
 373         total_compressed = min(total_compressed, max_uncompressed);
 374         num_bytes = (end - start + blocksize) & ~(blocksize - 1);
 375         num_bytes = max(blocksize,  num_bytes);
 376         total_in = 0;
 377         ret = 0;
 378
 379         /*
 380          * we do compression for mount -o compress and when the
 381          * inode has not been flagged as nocompress.  This flag can
 382          * change at any time if we discover bad compression ratios.
 383          */
 384         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS) &&
 385             (btrfs_test_opt(root, COMPRESS) ||
 386              (BTRFS_I(inode)->force_compress) ||
 387              (BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS))) {
 388                 WARN_ON(pages);
 389                 pages = kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
 390                 BUG_ON(!pages);
 391
 392                 if (BTRFS_I(inode)->force_compress)
 393                         compress_type = BTRFS_I(inode)->force_compress;
 394
 395                 ret = btrfs_compress_pages(compress_type,
 396                                            inode->i_mapping, start,
 397                                            total_compressed, pages,
 398                                            nr_pages, &nr_pages_ret,
 399                                            &total_in,
 400                                            &total_compressed,
 401                                            max_compressed);
 402
 403                 if (!ret) {
 404                         unsigned long offset = total_compressed &
 405                                 (PAGE_CACHE_SIZE - 1);
 406                         struct page *page = pages[nr_pages_ret - 1];
 407                         char *kaddr;
 408
 409                         /* zero the tail end of the last page, we might be
 410                          * sending it down to disk
 411                          */
 412                         if (offset) {
 413                                 kaddr = kmap_atomic(page, KM_USER0);
 414                                 memset(kaddr + offset, 0,
 415                                        PAGE_CACHE_SIZE - offset);
 416                                 kunmap_atomic(kaddr, KM_USER0);
 417                         }
 418                         will_compress = 1;
 419                 }
 420         }
 421         if (start == 0) {
 422                 trans = btrfs_join_transaction(root, 1);
 423                 BUG_ON(IS_ERR(trans));
 424                 btrfs_set_trans_block_group(trans, inode);
 425                 trans->block_rsv = &root->fs_info->delalloc_block_rsv;
 426
 427                 /* lets try to make an inline extent */
 428                 if (ret || total_in < (actual_end - start)) {
 429                         /* we didn't compress the entire range, try
 430                          * to make an uncompressed inline extent.
 431                          */
 432                         ret = cow_file_range_inline(trans, root, inode,
 433                                                     start, end, 0, 0, NULL);
 434                 } else {
 435                         /* try making a compressed inline extent */
 436                         ret = cow_file_range_inline(trans, root, inode,
 437                                                     start, end,
 438                                                     total_compressed,
 439                                                     compress_type, pages);
 440                 }
 441                 if (ret == 0) {
 442                         /*
 443                          * inline extent creation worked, we don't need
 444                          * to create any more async work items.  Unlock
 445                          * and free up our temp pages.
 446                          */
 447                         extent_clear_unlock_delalloc(inode,
 448                              &BTRFS_I(inode)->io_tree,
 449                              start, end, NULL,
 450                              EXTENT_CLEAR_UNLOCK_PAGE | EXTENT_CLEAR_DIRTY |
 451                              EXTENT_CLEAR_DELALLOC |
 452                              EXTENT_SET_WRITEBACK | EXTENT_END_WRITEBACK);
 453
 454                         btrfs_end_transaction(trans, root);
 455                         goto free_pages_out;
 456                 }
 457                 btrfs_end_transaction(trans, root);
 458         }
 459
 460         if (will_compress) {
 461                 /*
 462                  * we aren't doing an inline extent round the compressed size
 463                  * up to a block size boundary so the allocator does sane
 464                  * things
 465                  */
 466                 total_compressed = (total_compressed + blocksize - 1) &
 467                         ~(blocksize - 1);
 468
 469                 /*
 470                  * one last check to make sure the compression is really a
 471                  * win, compare the page count read with the blocks on disk
 472                  */
 473                 total_in = (total_in + PAGE_CACHE_SIZE - 1) &
 474                         ~(PAGE_CACHE_SIZE - 1);
 475                 if (total_compressed >= total_in) {
 476                         will_compress = 0;
 477                 } else {
 478                         num_bytes = total_in;
 479                 }
 480         }
 481         if (!will_compress && pages) {
 482                 /*
 483                  * the compression code ran but failed to make things smaller,
 484                  * free any pages it allocated and our page pointer array
 485                  */
 486                 for (i = 0; i < nr_pages_ret; i++) {
 487                         WARN_ON(pages[i]->mapping);
 488                         page_cache_release(pages[i]);
 489                 }
 490                 kfree(pages);
 491                 pages = NULL;
 492                 total_compressed = 0;
 493                 nr_pages_ret = 0;
 494
 495                 /* flag the file so we don't compress in the future */
 496                 if (!btrfs_test_opt(root, FORCE_COMPRESS) &&
 497                     !(BTRFS_I(inode)->force_compress)) {
 498                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 499                 }
 500         }
 501         if (will_compress) {
 502                 *num_added += 1;
 503
 504                 /* the async work queues will take care of doing actual
 505                  * allocation on disk for these compressed pages,
 506                  * and will submit them to the elevator.
 507                  */
 508                 add_async_extent(async_cow, start, num_bytes,
 509                                  total_compressed, pages, nr_pages_ret,
 510                                  compress_type);
 511
 512                 if (start + num_bytes < end) {
 513                         start += num_bytes;
 514                         pages = NULL;
 515                         cond_resched();
 516                         goto again;
 517                 }
 518         } else {
 519 cleanup_and_bail_uncompressed:
 520                 /*
 521                  * No compression, but we still need to write the pages in
 522                  * the file we've been given so far.  redirty the locked
 523                  * page if it corresponds to our extent and set things up
 524                  * for the async work queue to run cow_file_range to do
 525                  * the normal delalloc dance
 526                  */
 527                 if (page_offset(locked_page) >= start &&
 528                     page_offset(locked_page) <= end) {
 529                         __set_page_dirty_nobuffers(locked_page);
 530                         /* unlocked later on in the async handlers */
 531                 }
 532                 add_async_extent(async_cow, start, end - start + 1,
 533                                  0, NULL, 0, BTRFS_COMPRESS_NONE);
 534                 *num_added += 1;
 535         }
 536
 537 out:
 538         return 0;
 539
 540 free_pages_out:
 541         for (i = 0; i < nr_pages_ret; i++) {
 542                 WARN_ON(pages[i]->mapping);
 543                 page_cache_release(pages[i]);
 544         }
 545         kfree(pages);
 546
 547         goto out;
 548 }
 549
 550 /*
 551  * phase two of compressed writeback.  This is the ordered portion
 552  * of the code, which only gets called in the order the work was
 553  * queued.  We walk all the async extents created by compress_file_range
 554  * and send them down to the disk.
 555  */
 556 static noinline int submit_compressed_extents(struct inode *inode,
 557                                               struct async_cow *async_cow)
 558 {
 559         struct async_extent *async_extent;
 560         u64 alloc_hint = 0;
 561         struct btrfs_trans_handle *trans;
 562         struct btrfs_key ins;
 563         struct extent_map *em;
 564         struct btrfs_root *root = BTRFS_I(inode)->root;
 565         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 566         struct extent_io_tree *io_tree;
 567         int ret = 0;
 568
 569         if (list_empty(&async_cow->extents))
 570                 return 0;
 571
 572
 573         while (!list_empty(&async_cow->extents)) {
 574                 async_extent = list_entry(async_cow->extents.next,
 575                                           struct async_extent, list);
 576                 list_del(&async_extent->list);
 577
 578                 io_tree = &BTRFS_I(inode)->io_tree;
 579
 580 retry:
 581                 /* did the compression code fall back to uncompressed IO? */
 582                 if (!async_extent->pages) {
 583                         int page_started = 0;
 584                         unsigned long nr_written = 0;
 585
 586                         lock_extent(io_tree, async_extent->start,
 587                                          async_extent->start +
 588                                          async_extent->ram_size - 1, GFP_NOFS);
 589
 590                         /* allocate blocks */
 591                         ret = cow_file_range(inode, async_cow->locked_page,
 592                                              async_extent->start,
 593                                              async_extent->start +
 594                                              async_extent->ram_size - 1,
 595                                              &page_started, &nr_written, 0);
 596
 597                         /*
 598                          * if page_started, cow_file_range inserted an
 599                          * inline extent and took care of all the unlocking
 600                          * and IO for us.  Otherwise, we need to submit
 601                          * all those pages down to the drive.
 602                          */
 603                         if (!page_started && !ret)
 604                                 extent_write_locked_range(io_tree,
 605                                                   inode, async_extent->start,
 606                                                   async_extent->start +
 607                                                   async_extent->ram_size - 1,
 608                                                   btrfs_get_extent,
 609                                                   WB_SYNC_ALL);
 610                         kfree(async_extent);
 611                         cond_resched();
 612                         continue;
 613                 }
 614
 615                 lock_extent(io_tree, async_extent->start,
 616                             async_extent->start + async_extent->ram_size - 1,
 617                             GFP_NOFS);
 618
 619                 trans = btrfs_join_transaction(root, 1);
 620                 BUG_ON(IS_ERR(trans));
 621                 ret = btrfs_reserve_extent(trans, root,
 622                                            async_extent->compressed_size,
 623                                            async_extent->compressed_size,
 624                                            0, alloc_hint,
 625                                            (u64)-1, &ins, 1);
 626                 btrfs_end_transaction(trans, root);
 627
 628                 if (ret) {
 629                         int i;
 630                         for (i = 0; i < async_extent->nr_pages; i++) {
 631                                 WARN_ON(async_extent->pages[i]->mapping);
 632                                 page_cache_release(async_extent->pages[i]);
 633                         }
 634                         kfree(async_extent->pages);
 635                         async_extent->nr_pages = 0;
 636                         async_extent->pages = NULL;
 637                         unlock_extent(io_tree, async_extent->start,
 638                                       async_extent->start +
 639                                       async_extent->ram_size - 1, GFP_NOFS);
 640                         goto retry;
 641                 }
 642
 643                 /*
 644                  * here we're doing allocation and writeback of the
 645                  * compressed pages
 646                  */
 647                 btrfs_drop_extent_cache(inode, async_extent->start,
 648                                         async_extent->start +
 649                                         async_extent->ram_size - 1, 0);
 650
 651                 em = alloc_extent_map(GFP_NOFS);
 652                 BUG_ON(!em);
 653                 em->start = async_extent->start;
 654                 em->len = async_extent->ram_size;
 655                 em->orig_start = em->start;
 656
 657                 em->block_start = ins.objectid;
 658                 em->block_len = ins.offset;
 659                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 660                 em->compress_type = async_extent->compress_type;
 661                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 662                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 663
 664                 while (1) {
 665                         write_lock(&em_tree->lock);
 666                         ret = add_extent_mapping(em_tree, em);
 667                         write_unlock(&em_tree->lock);
 668                         if (ret != -EEXIST) {
 669                                 free_extent_map(em);
 670                                 break;
 671                         }
 672                         btrfs_drop_extent_cache(inode, async_extent->start,
 673                                                 async_extent->start +
 674                                                 async_extent->ram_size - 1, 0);
 675                 }
 676
 677                 ret = btrfs_add_ordered_extent_compress(inode,
 678                                                 async_extent->start,
 679                                                 ins.objectid,
 680                                                 async_extent->ram_size,
 681                                                 ins.offset,
 682                                                 BTRFS_ORDERED_COMPRESSED,
 683                                                 async_extent->compress_type);
 684                 BUG_ON(ret);
 685
 686                 /*
 687                  * clear dirty, set writeback and unlock the pages.
 688                  */
 689                 extent_clear_unlock_delalloc(inode,
 690                                 &BTRFS_I(inode)->io_tree,
 691                                 async_extent->start,
 692                                 async_extent->start +
 693                                 async_extent->ram_size - 1,
 694                                 NULL, EXTENT_CLEAR_UNLOCK_PAGE |
 695                                 EXTENT_CLEAR_UNLOCK |
 696                                 EXTENT_CLEAR_DELALLOC |
 697                                 EXTENT_CLEAR_DIRTY | EXTENT_SET_WRITEBACK);
 698
 699                 ret = btrfs_submit_compressed_write(inode,
 700                                     async_extent->start,
 701                                     async_extent->ram_size,
 702                                     ins.objectid,
 703                                     ins.offset, async_extent->pages,
 704                                     async_extent->nr_pages);
 705
 706                 BUG_ON(ret);
 707                 alloc_hint = ins.objectid + ins.offset;
 708                 kfree(async_extent);
 709                 cond_resched();
 710         }
 711
 712         return 0;
 713 }
 714
 715 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
 716                                       u64 num_bytes)
 717 {
 718         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 719         struct extent_map *em;
 720         u64 alloc_hint = 0;
 721
 722         read_lock(&em_tree->lock);
 723         em = search_extent_mapping(em_tree, start, num_bytes);
 724         if (em) {
 725                 /*
 726                  * if block start isn't an actual block number then find the
 727                  * first block in this inode and use that as a hint.  If that
 728                  * block is also bogus then just don't worry about it.
 729                  */
 730                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
 731                         free_extent_map(em);
 732                         em = search_extent_mapping(em_tree, 0, 0);
 733                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
 734                                 alloc_hint = em->block_start;
 735                         if (em)
 736                                 free_extent_map(em);
 737                 } else {
 738                         alloc_hint = em->block_start;
 739                         free_extent_map(em);
 740                 }
 741         }
 742         read_unlock(&em_tree->lock);
 743
 744         return alloc_hint;
 745 }
 746
 747 /*
 748  * when extent_io.c finds a delayed allocation range in the file,
 749  * the call backs end up in this code.  The basic idea is to
 750  * allocate extents on disk for the range, and create ordered data structs
 751  * in ram to track those extents.
 752  *
 753  * locked_page is the page that writepage had locked already.  We use
 754  * it to make sure we don't do extra locks or unlocks.
 755  *
 756  * *page_started is set to one if we unlock locked_page and do everything
 757  * required to start IO on it.  It may be clean and already done with
 758  * IO when we return.
 759  */
 760 static noinline int cow_file_range(struct inode *inode,
 761                                    struct page *locked_page,
 762                                    u64 start, u64 end, int *page_started,
 763                                    unsigned long *nr_written,
 764                                    int unlock)
 765 {
 766         struct btrfs_root *root = BTRFS_I(inode)->root;
 767         struct btrfs_trans_handle *trans;
 768         u64 alloc_hint = 0;
 769         u64 num_bytes;
 770         unsigned long ram_size;
 771         u64 disk_num_bytes;
 772         u64 cur_alloc_size;
 773         u64 blocksize = root->sectorsize;
 774         struct btrfs_key ins;
 775         struct extent_map *em;
 776         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 777         int ret = 0;
 778
 779         BUG_ON(root == root->fs_info->tree_root);
 780         trans = btrfs_join_transaction(root, 1);
 781         BUG_ON(IS_ERR(trans));
 782         btrfs_set_trans_block_group(trans, inode);
 783         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
 784
 785         num_bytes = (end - start + blocksize) & ~(blocksize - 1);
 786         num_bytes = max(blocksize,  num_bytes);
 787         disk_num_bytes = num_bytes;
 788         ret = 0;
 789
 790         if (start == 0) {
 791                 /* lets try to make an inline extent */
 792                 ret = cow_file_range_inline(trans, root, inode,
 793                                             start, end, 0, 0, NULL);
 794                 if (ret == 0) {
 795                         extent_clear_unlock_delalloc(inode,
 796                                      &BTRFS_I(inode)->io_tree,
 797                                      start, end, NULL,
 798                                      EXTENT_CLEAR_UNLOCK_PAGE |
 799                                      EXTENT_CLEAR_UNLOCK |
 800                                      EXTENT_CLEAR_DELALLOC |
 801                                      EXTENT_CLEAR_DIRTY |
 802                                      EXTENT_SET_WRITEBACK |
 803                                      EXTENT_END_WRITEBACK);
 804
 805                         *nr_written = *nr_written +
 806                              (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
 807                         *page_started = 1;
 808                         ret = 0;
 809                         goto out;
 810                 }
 811         }
 812
 813         BUG_ON(disk_num_bytes >
 814                btrfs_super_total_bytes(&root->fs_info->super_copy));
 815
 816         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
 817         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
 818
 819         while (disk_num_bytes > 0) {
 820                 unsigned long op;
 821
 822                 cur_alloc_size = disk_num_bytes;
 823                 ret = btrfs_reserve_extent(trans, root, cur_alloc_size,
 824                                            root->sectorsize, 0, alloc_hint,
 825                                            (u64)-1, &ins, 1);
 826                 BUG_ON(ret);
 827
 828                 em = alloc_extent_map(GFP_NOFS);
 829                 BUG_ON(!em);
 830                 em->start = start;
 831                 em->orig_start = em->start;
 832                 ram_size = ins.offset;
 833                 em->len = ins.offset;
 834
 835                 em->block_start = ins.objectid;
 836                 em->block_len = ins.offset;
 837                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 838                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 839
 840                 while (1) {
 841                         write_lock(&em_tree->lock);
 842                         ret = add_extent_mapping(em_tree, em);
 843                         write_unlock(&em_tree->lock);
 844                         if (ret != -EEXIST) {
 845                                 free_extent_map(em);
 846                                 break;
 847                         }
 848                         btrfs_drop_extent_cache(inode, start,
 849                                                 start + ram_size - 1, 0);
 850                 }
 851
 852                 cur_alloc_size = ins.offset;
 853                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
 854                                                ram_size, cur_alloc_size, 0);
 855                 BUG_ON(ret);
 856
 857                 if (root->root_key.objectid ==
 858                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
 859                         ret = btrfs_reloc_clone_csums(inode, start,
 860                                                       cur_alloc_size);
 861                         BUG_ON(ret);
 862                 }
 863
 864                 if (disk_num_bytes < cur_alloc_size)
 865                         break;
 866
 867                 /* we're not doing compressed IO, don't unlock the first
 868                  * page (which the caller expects to stay locked), don't
 869                  * clear any dirty bits and don't set any writeback bits
 870                  *
 871                  * Do set the Private2 bit so we know this page was properly
 872                  * setup for writepage
 873                  */
 874                 op = unlock ? EXTENT_CLEAR_UNLOCK_PAGE : 0;
 875                 op |= EXTENT_CLEAR_UNLOCK | EXTENT_CLEAR_DELALLOC |
 876                         EXTENT_SET_PRIVATE2;
 877
 878                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
 879                                              start, start + ram_size - 1,
 880                                              locked_page, op);
 881                 disk_num_bytes -= cur_alloc_size;
 882                 num_bytes -= cur_alloc_size;
 883                 alloc_hint = ins.objectid + ins.offset;
 884                 start += cur_alloc_size;
 885         }
 886 out:
 887         ret = 0;
 888         btrfs_end_transaction(trans, root);
 889
 890         return ret;
 891 }
 892
 893 /*
 894  * work queue call back to started compression on a file and pages
 895  */
 896 static noinline void async_cow_start(struct btrfs_work *work)
 897 {
 898         struct async_cow *async_cow;
 899         int num_added = 0;
 900         async_cow = container_of(work, struct async_cow, work);
 901
 902         compress_file_range(async_cow->inode, async_cow->locked_page,
 903                             async_cow->start, async_cow->end, async_cow,
 904                             &num_added);
 905         if (num_added == 0)
 906                 async_cow->inode = NULL;
 907 }
 908
 909 /*
 910  * work queue call back to submit previously compressed pages
 911  */
 912 static noinline void async_cow_submit(struct btrfs_work *work)
 913 {
 914         struct async_cow *async_cow;
 915         struct btrfs_root *root;
 916         unsigned long nr_pages;
 917
 918         async_cow = container_of(work, struct async_cow, work);
 919
 920         root = async_cow->root;
 921         nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >>
 922                 PAGE_CACHE_SHIFT;
 923
 924         atomic_sub(nr_pages, &root->fs_info->async_delalloc_pages);
 925
 926         if (atomic_read(&root->fs_info->async_delalloc_pages) <
 927             5 * 1042 * 1024 &&
 928             waitqueue_active(&root->fs_info->async_submit_wait))
 929                 wake_up(&root->fs_info->async_submit_wait);
 930
 931         if (async_cow->inode)
 932                 submit_compressed_extents(async_cow->inode, async_cow);
 933 }
 934
 935 static noinline void async_cow_free(struct btrfs_work *work)
 936 {
 937         struct async_cow *async_cow;
 938         async_cow = container_of(work, struct async_cow, work);
 939         kfree(async_cow);
 940 }
 941
 942 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
 943                                 u64 start, u64 end, int *page_started,
 944                                 unsigned long *nr_written)
 945 {
 946         struct async_cow *async_cow;
 947         struct btrfs_root *root = BTRFS_I(inode)->root;
 948         unsigned long nr_pages;
 949         u64 cur_end;
 950         int limit = 10 * 1024 * 1042;
 951
 952         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
 953                          1, 0, NULL, GFP_NOFS);
 954         while (start < end) {
 955                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
 956                 BUG_ON(!async_cow);
 957                 async_cow->inode = inode;
 958                 async_cow->root = root;
 959                 async_cow->locked_page = locked_page;
 960                 async_cow->start = start;
 961
 962                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
 963                         cur_end = end;
 964                 else
 965                         cur_end = min(end, start + 512 * 1024 - 1);
 966
 967                 async_cow->end = cur_end;
 968                 INIT_LIST_HEAD(&async_cow->extents);
 969
 970                 async_cow->work.func = async_cow_start;
 971                 async_cow->work.ordered_func = async_cow_submit;
 972                 async_cow->work.ordered_free = async_cow_free;
 973                 async_cow->work.flags = 0;
 974
 975                 nr_pages = (cur_end - start + PAGE_CACHE_SIZE) >>
 976                         PAGE_CACHE_SHIFT;
 977                 atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
 978
 979                 btrfs_queue_worker(&root->fs_info->delalloc_workers,
 980                                    &async_cow->work);
 981
 982                 if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
 983                         wait_event(root->fs_info->async_submit_wait,
 984                            (atomic_read(&root->fs_info->async_delalloc_pages) <
 985                             limit));
 986                 }
 987
 988                 while (atomic_read(&root->fs_info->async_submit_draining) &&
 989                       atomic_read(&root->fs_info->async_delalloc_pages)) {
 990                         wait_event(root->fs_info->async_submit_wait,
 991                           (atomic_read(&root->fs_info->async_delalloc_pages) ==
 992                            0));
 993                 }
 994
 995                 *nr_written += nr_pages;
 996                 start = cur_end + 1;
 997         }
 998         *page_started = 1;
 999         return 0;
1000 }
1001
1002 static noinline int csum_exist_in_range(struct btrfs_root *root,
1003                                         u64 bytenr, u64 num_bytes)
1004 {
1005         int ret;
1006         struct btrfs_ordered_sum *sums;
1007         LIST_HEAD(list);
1008
1009         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
1010                                        bytenr + num_bytes - 1, &list);
1011         if (ret == 0 && list_empty(&list))
1012                 return 0;
1013
1014         while (!list_empty(&list)) {
1015                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1016                 list_del(&sums->list);
1017                 kfree(sums);
1018         }
1019         return 1;
1020 }
1021
1022 /*
1023  * when nowcow writeback call back.  This checks for snapshots or COW copies
1024  * of the extents that exist in the file, and COWs the file as required.
1025  *
1026  * If no cow copies or snapshots exist, we write directly to the existing
1027  * blocks on disk
1028  */
1029 static noinline int run_delalloc_nocow(struct inode *inode,
1030                                        struct page *locked_page,
1031                               u64 start, u64 end, int *page_started, int force,
1032                               unsigned long *nr_written)
1033 {
1034         struct btrfs_root *root = BTRFS_I(inode)->root;
1035         struct btrfs_trans_handle *trans;
1036         struct extent_buffer *leaf;
1037         struct btrfs_path *path;
1038         struct btrfs_file_extent_item *fi;
1039         struct btrfs_key found_key;
1040         u64 cow_start;
1041         u64 cur_offset;
1042         u64 extent_end;
1043         u64 extent_offset;
1044         u64 disk_bytenr;
1045         u64 num_bytes;
1046         int extent_type;
1047         int ret;
1048         int type;
1049         int nocow;
1050         int check_prev = 1;
1051         bool nolock = false;
1052
1053         path = btrfs_alloc_path();
1054         BUG_ON(!path);
1055         if (root == root->fs_info->tree_root) {
1056                 nolock = true;
1057                 trans = btrfs_join_transaction_nolock(root, 1);
1058         } else {
1059                 trans = btrfs_join_transaction(root, 1);
1060         }
1061         BUG_ON(IS_ERR(trans));
1062
1063         cow_start = (u64)-1;
1064         cur_offset = start;
1065         while (1) {
1066                 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
1067                                                cur_offset, 0);
1068                 BUG_ON(ret < 0);
1069                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1070                         leaf = path->nodes[0];
1071                         btrfs_item_key_to_cpu(leaf, &found_key,
1072                                               path->slots[0] - 1);
1073                         if (found_key.objectid == inode->i_ino &&
1074                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1075                                 path->slots[0]--;
1076                 }
1077                 check_prev = 0;
1078 next_slot:
1079                 leaf = path->nodes[0];
1080                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1081                         ret = btrfs_next_leaf(root, path);
1082                         if (ret < 0)
1083                                 BUG_ON(1);
1084                         if (ret > 0)
1085                                 break;
1086                         leaf = path->nodes[0];
1087                 }
1088
1089                 nocow = 0;
1090                 disk_bytenr = 0;
1091                 num_bytes = 0;
1092                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1093
1094                 if (found_key.objectid > inode->i_ino ||
1095                     found_key.type > BTRFS_EXTENT_DATA_KEY ||
1096                     found_key.offset > end)
1097                         break;
1098
1099                 if (found_key.offset > cur_offset) {
1100                         extent_end = found_key.offset;
1101                         extent_type = 0;
1102                         goto out_check;
1103                 }
1104
1105                 fi = btrfs_item_ptr(leaf, path->slots[0],
1106                                     struct btrfs_file_extent_item);
1107                 extent_type = btrfs_file_extent_type(leaf, fi);
1108
1109                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1110                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1111                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1112                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1113                         extent_end = found_key.offset +
1114                                 btrfs_file_extent_num_bytes(leaf, fi);
1115                         if (extent_end <= start) {
1116                                 path->slots[0]++;
1117                                 goto next_slot;
1118                         }
1119                         if (disk_bytenr == 0)
1120                                 goto out_check;
1121                         if (btrfs_file_extent_compression(leaf, fi) ||
1122                             btrfs_file_extent_encryption(leaf, fi) ||
1123                             btrfs_file_extent_other_encoding(leaf, fi))
1124                                 goto out_check;
1125                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1126                                 goto out_check;
1127                         if (btrfs_extent_readonly(root, disk_bytenr))
1128                                 goto out_check;
1129                         if (btrfs_cross_ref_exist(trans, root, inode->i_ino,
1130                                                   found_key.offset -
1131                                                   extent_offset, disk_bytenr))
1132                                 goto out_check;
1133                         disk_bytenr += extent_offset;
1134                         disk_bytenr += cur_offset - found_key.offset;
1135                         num_bytes = min(end + 1, extent_end) - cur_offset;
1136                         /*
1137                          * force cow if csum exists in the range.
1138                          * this ensure that csum for a given extent are
1139                          * either valid or do not exist.
1140                          */
1141                         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
1142                                 goto out_check;
1143                         nocow = 1;
1144                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1145                         extent_end = found_key.offset +
1146                                 btrfs_file_extent_inline_len(leaf, fi);
1147                         extent_end = ALIGN(extent_end, root->sectorsize);
1148                 } else {
1149                         BUG_ON(1);
1150                 }
1151 out_check:
1152                 if (extent_end <= start) {
1153                         path->slots[0]++;
1154                         goto next_slot;
1155                 }
1156                 if (!nocow) {
1157                         if (cow_start == (u64)-1)
1158                                 cow_start = cur_offset;
1159                         cur_offset = extent_end;
1160                         if (cur_offset > end)
1161                                 break;
1162                         path->slots[0]++;
1163                         goto next_slot;
1164                 }
1165
1166                 btrfs_release_path(root, path);
1167                 if (cow_start != (u64)-1) {
1168                         ret = cow_file_range(inode, locked_page, cow_start,
1169                                         found_key.offset - 1, page_started,
1170                                         nr_written, 1);
1171                         BUG_ON(ret);
1172                         cow_start = (u64)-1;
1173                 }
1174
1175                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1176                         struct extent_map *em;
1177                         struct extent_map_tree *em_tree;
1178                         em_tree = &BTRFS_I(inode)->extent_tree;
1179                         em = alloc_extent_map(GFP_NOFS);
1180                         BUG_ON(!em);
1181                         em->start = cur_offset;
1182                         em->orig_start = em->start;
1183                         em->len = num_bytes;
1184                         em->block_len = num_bytes;
1185                         em->block_start = disk_bytenr;
1186                         em->bdev = root->fs_info->fs_devices->latest_bdev;
1187                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
1188                         while (1) {
1189                                 write_lock(&em_tree->lock);
1190                                 ret = add_extent_mapping(em_tree, em);
1191                                 write_unlock(&em_tree->lock);
1192                                 if (ret != -EEXIST) {
1193                                         free_extent_map(em);
1194                                         break;
1195                                 }
1196                                 btrfs_drop_extent_cache(inode, em->start,
1197                                                 em->start + em->len - 1, 0);
1198                         }
1199                         type = BTRFS_ORDERED_PREALLOC;
1200                 } else {
1201                         type = BTRFS_ORDERED_NOCOW;
1202                 }
1203
1204                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1205                                                num_bytes, num_bytes, type);
1206                 BUG_ON(ret);
1207
1208                 if (root->root_key.objectid ==
1209                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1210                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1211                                                       num_bytes);
1212                         BUG_ON(ret);
1213                 }
1214
1215                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
1216                                 cur_offset, cur_offset + num_bytes - 1,
1217                                 locked_page, EXTENT_CLEAR_UNLOCK_PAGE |
1218                                 EXTENT_CLEAR_UNLOCK | EXTENT_CLEAR_DELALLOC |
1219                                 EXTENT_SET_PRIVATE2);
1220                 cur_offset = extent_end;
1221                 if (cur_offset > end)
1222                         break;
1223         }
1224         btrfs_release_path(root, path);
1225
1226         if (cur_offset <= end && cow_start == (u64)-1)
1227                 cow_start = cur_offset;
1228         if (cow_start != (u64)-1) {
1229                 ret = cow_file_range(inode, locked_page, cow_start, end,
1230                                      page_started, nr_written, 1);
1231                 BUG_ON(ret);
1232         }
1233
1234         if (nolock) {
1235                 ret = btrfs_end_transaction_nolock(trans, root);
1236                 BUG_ON(ret);
1237         } else {
1238                 ret = btrfs_end_transaction(trans, root);
1239                 BUG_ON(ret);
1240         }
1241         btrfs_free_path(path);
1242         return 0;
1243 }
1244
1245 /*
1246  * extent_io.c call back to do delayed allocation processing
1247  */
1248 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1249                               u64 start, u64 end, int *page_started,
1250                               unsigned long *nr_written)
1251 {
1252         int ret;
1253         struct btrfs_root *root = BTRFS_I(inode)->root;
1254
1255         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW)
1256                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1257                                          page_started, 1, nr_written);
1258         else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC)
1259                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1260                                          page_started, 0, nr_written);
1261         else if (!btrfs_test_opt(root, COMPRESS) &&
1262                  !(BTRFS_I(inode)->force_compress) &&
1263                  !(BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS))
1264                 ret = cow_file_range(inode, locked_page, start, end,
1265                                       page_started, nr_written, 1);
1266         else
1267                 ret = cow_file_range_async(inode, locked_page, start, end,
1268                                            page_started, nr_written);
1269         return ret;
1270 }
1271
1272 static int btrfs_split_extent_hook(struct inode *inode,
1273                                    struct extent_state *orig, u64 split)
1274 {
1275         /* not delalloc, ignore it */
1276         if (!(orig->state & EXTENT_DELALLOC))
1277                 return 0;
1278
1279         atomic_inc(&BTRFS_I(inode)->outstanding_extents);
1280         return 0;
1281 }
1282
1283 /*
1284  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1285  * extents so we can keep track of new extents that are just merged onto old
1286  * extents, such as when we are doing sequential writes, so we can properly
1287  * account for the metadata space we'll need.
1288  */
1289 static int btrfs_merge_extent_hook(struct inode *inode,
1290                                    struct extent_state *new,
1291                                    struct extent_state *other)
1292 {
1293         /* not delalloc, ignore it */
1294         if (!(other->state & EXTENT_DELALLOC))
1295                 return 0;
1296
1297         atomic_dec(&BTRFS_I(inode)->outstanding_extents);
1298         return 0;
1299 }
1300
1301 /*
1302  * extent_io.c set_bit_hook, used to track delayed allocation
1303  * bytes in this file, and to maintain the list of inodes that
1304  * have pending delalloc work to be done.
1305  */
1306 static int btrfs_set_bit_hook(struct inode *inode,
1307                               struct extent_state *state, int *bits)
1308 {
1309
1310         /*
1311          * set_bit and clear bit hooks normally require _irqsave/restore
1312          * but in this case, we are only testeing for the DELALLOC
1313          * bit, which is only set or cleared with irqs on
1314          */
1315         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1316                 struct btrfs_root *root = BTRFS_I(inode)->root;
1317                 u64 len = state->end + 1 - state->start;
1318                 int do_list = (root->root_key.objectid !=
1319                                BTRFS_ROOT_TREE_OBJECTID);
1320
1321                 if (*bits & EXTENT_FIRST_DELALLOC)
1322                         *bits &= ~EXTENT_FIRST_DELALLOC;
1323                 else
1324                         atomic_inc(&BTRFS_I(inode)->outstanding_extents);
1325
1326                 spin_lock(&root->fs_info->delalloc_lock);
1327                 BTRFS_I(inode)->delalloc_bytes += len;
1328                 root->fs_info->delalloc_bytes += len;
1329                 if (do_list && list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1330                         list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1331                                       &root->fs_info->delalloc_inodes);
1332                 }
1333                 spin_unlock(&root->fs_info->delalloc_lock);
1334         }
1335         return 0;
1336 }
1337
1338 /*
1339  * extent_io.c clear_bit_hook, see set_bit_hook for why
1340  */
1341 static int btrfs_clear_bit_hook(struct inode *inode,
1342                                 struct extent_state *state, int *bits)
1343 {
1344         /*
1345          * set_bit and clear bit hooks normally require _irqsave/restore
1346          * but in this case, we are only testeing for the DELALLOC
1347          * bit, which is only set or cleared with irqs on
1348          */
1349         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1350                 struct btrfs_root *root = BTRFS_I(inode)->root;
1351                 u64 len = state->end + 1 - state->start;
1352                 int do_list = (root->root_key.objectid !=
1353                                BTRFS_ROOT_TREE_OBJECTID);
1354
1355                 if (*bits & EXTENT_FIRST_DELALLOC)
1356                         *bits &= ~EXTENT_FIRST_DELALLOC;
1357                 else if (!(*bits & EXTENT_DO_ACCOUNTING))
1358                         atomic_dec(&BTRFS_I(inode)->outstanding_extents);
1359
1360                 if (*bits & EXTENT_DO_ACCOUNTING)
1361                         btrfs_delalloc_release_metadata(inode, len);
1362
1363                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
1364                     && do_list)
1365                         btrfs_free_reserved_data_space(inode, len);
1366
1367                 spin_lock(&root->fs_info->delalloc_lock);
1368                 root->fs_info->delalloc_bytes -= len;
1369                 BTRFS_I(inode)->delalloc_bytes -= len;
1370
1371                 if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
1372                     !list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1373                         list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1374                 }
1375                 spin_unlock(&root->fs_info->delalloc_lock);
1376         }
1377         return 0;
1378 }
1379
1380 /*
1381  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1382  * we don't create bios that span stripes or chunks
1383  */
1384 int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
1385                          size_t size, struct bio *bio,
1386                          unsigned long bio_flags)
1387 {
1388         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
1389         struct btrfs_mapping_tree *map_tree;
1390         u64 logical = (u64)bio->bi_sector << 9;
1391         u64 length = 0;
1392         u64 map_length;
1393         int ret;
1394
1395         if (bio_flags & EXTENT_BIO_COMPRESSED)
1396                 return 0;
1397
1398         length = bio->bi_size;
1399         map_tree = &root->fs_info->mapping_tree;
1400         map_length = length;
1401         ret = btrfs_map_block(map_tree, READ, logical,
1402                               &map_length, NULL, 0);
1403
1404         if (map_length < length + size)
1405                 return 1;
1406         return ret;
1407 }
1408
1409 /*
1410  * in order to insert checksums into the metadata in large chunks,
1411  * we wait until bio submission time.   All the pages in the bio are
1412  * checksummed and sums are attached onto the ordered extent record.
1413  *
1414  * At IO completion time the cums attached on the ordered extent record
1415  * are inserted into the btree
1416  */
1417 static int __btrfs_submit_bio_start(struct inode *inode, int rw,
1418                                     struct bio *bio, int mirror_num,
1419                                     unsigned long bio_flags,
1420                                     u64 bio_offset)
1421 {
1422         struct btrfs_root *root = BTRFS_I(inode)->root;
1423         int ret = 0;
1424
1425         ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1426         BUG_ON(ret);
1427         return 0;
1428 }
1429
1430 /*
1431  * in order to insert checksums into the metadata in large chunks,
1432  * we wait until bio submission time.   All the pages in the bio are
1433  * checksummed and sums are attached onto the ordered extent record.
1434  *
1435  * At IO completion time the cums attached on the ordered extent record
1436  * are inserted into the btree
1437  */
1438 static int __btrfs_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
1439                           int mirror_num, unsigned long bio_flags,
1440                           u64 bio_offset)
1441 {
1442         struct btrfs_root *root = BTRFS_I(inode)->root;
1443         return btrfs_map_bio(root, rw, bio, mirror_num, 1);
1444 }
1445
1446 /*
1447  * extent_io.c submission hook. This does the right thing for csum calculation
1448  * on write, or reading the csums from the tree before a read
1449  */
1450 static int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
1451                           int mirror_num, unsigned long bio_flags,
1452                           u64 bio_offset)
1453 {
1454         struct btrfs_root *root = BTRFS_I(inode)->root;
1455         int ret = 0;
1456         int skip_sum;
1457
1458         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1459
1460         if (root == root->fs_info->tree_root)
1461                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 2);
1462         else
1463                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
1464         BUG_ON(ret);
1465
1466         if (!(rw & REQ_WRITE)) {
1467                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1468                         return btrfs_submit_compressed_read(inode, bio,
1469                                                     mirror_num, bio_flags);
1470                 } else if (!skip_sum) {
1471                         ret = btrfs_lookup_bio_sums(root, inode, bio, NULL);
1472                         if (ret)
1473                                 return ret;
1474                 }
1475                 goto mapit;
1476         } else if (!skip_sum) {
1477                 /* csum items have already been cloned */
1478                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1479                         goto mapit;
1480                 /* we're doing a write, do the async checksumming */
1481                 return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
1482                                    inode, rw, bio, mirror_num,
1483                                    bio_flags, bio_offset,
1484                                    __btrfs_submit_bio_start,
1485                                    __btrfs_submit_bio_done);
1486         }
1487
1488 mapit:
1489         return btrfs_map_bio(root, rw, bio, mirror_num, 0);
1490 }
1491
1492 /*
1493  * given a list of ordered sums record them in the inode.  This happens
1494  * at IO completion time based on sums calculated at bio submission time.
1495  */
1496 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1497                              struct inode *inode, u64 file_offset,
1498                              struct list_head *list)
1499 {
1500         struct btrfs_ordered_sum *sum;
1501
1502         btrfs_set_trans_block_group(trans, inode);
1503
1504         list_for_each_entry(sum, list, list) {
1505                 btrfs_csum_file_blocks(trans,
1506                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
1507         }
1508         return 0;
1509 }
1510
1511 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
1512                               struct extent_state **cached_state)
1513 {
1514         if ((end & (PAGE_CACHE_SIZE - 1)) == 0)
1515                 WARN_ON(1);
1516         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1517                                    cached_state, GFP_NOFS);
1518 }
1519
1520 /* see btrfs_writepage_start_hook for details on why this is required */
1521 struct btrfs_writepage_fixup {
1522         struct page *page;
1523         struct btrfs_work work;
1524 };
1525
1526 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1527 {
1528         struct btrfs_writepage_fixup *fixup;
1529         struct btrfs_ordered_extent *ordered;
1530         struct extent_state *cached_state = NULL;
1531         struct page *page;
1532         struct inode *inode;
1533         u64 page_start;
1534         u64 page_end;
1535
1536         fixup = container_of(work, struct btrfs_writepage_fixup, work);
1537         page = fixup->page;
1538 again:
1539         lock_page(page);
1540         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
1541                 ClearPageChecked(page);
1542                 goto out_page;
1543         }
1544
1545         inode = page->mapping->host;
1546         page_start = page_offset(page);
1547         page_end = page_offset(page) + PAGE_CACHE_SIZE - 1;
1548
1549         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end, 0,
1550                          &cached_state, GFP_NOFS);
1551
1552         /* already ordered? We're done */
1553         if (PagePrivate2(page))
1554                 goto out;
1555
1556         ordered = btrfs_lookup_ordered_extent(inode, page_start);
1557         if (ordered) {
1558                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
1559                                      page_end, &cached_state, GFP_NOFS);
1560                 unlock_page(page);
1561                 btrfs_start_ordered_extent(inode, ordered, 1);
1562                 goto again;
1563         }
1564
1565         BUG();
1566         btrfs_set_extent_delalloc(inode, page_start, page_end, &cached_state);
1567         ClearPageChecked(page);
1568 out:
1569         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
1570                              &cached_state, GFP_NOFS);
1571 out_page:
1572         unlock_page(page);
1573         page_cache_release(page);
1574         kfree(fixup);
1575 }
1576
1577 /*
1578  * There are a few paths in the higher layers of the kernel that directly
1579  * set the page dirty bit without asking the filesystem if it is a
1580  * good idea.  This causes problems because we want to make sure COW
1581  * properly happens and the data=ordered rules are followed.
1582  *
1583  * In our case any range that doesn't have the ORDERED bit set
1584  * hasn't been properly setup for IO.  We kick off an async process
1585  * to fix it up.  The async helper will wait for ordered extents, set
1586  * the delalloc bit and make it safe to write the page.
1587  */
1588 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
1589 {
1590         struct inode *inode = page->mapping->host;
1591         struct btrfs_writepage_fixup *fixup;
1592         struct btrfs_root *root = BTRFS_I(inode)->root;
1593
1594         /* this page is properly in the ordered list */
1595         if (TestClearPagePrivate2(page))
1596                 return 0;
1597
1598         if (PageChecked(page))
1599                 return -EAGAIN;
1600
1601         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
1602         if (!fixup)
1603                 return -EAGAIN;
1604
1605         SetPageChecked(page);
1606         page_cache_get(page);
1607         fixup->work.func = btrfs_writepage_fixup_worker;
1608         fixup->page = page;
1609         btrfs_queue_worker(&root->fs_info->fixup_workers, &fixup->work);
1610         return -EAGAIN;
1611 }
1612
1613 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
1614                                        struct inode *inode, u64 file_pos,
1615                                        u64 disk_bytenr, u64 disk_num_bytes,
1616                                        u64 num_bytes, u64 ram_bytes,
1617                                        u8 compression, u8 encryption,
1618                                        u16 other_encoding, int extent_type)
1619 {
1620         struct btrfs_root *root = BTRFS_I(inode)->root;
1621         struct btrfs_file_extent_item *fi;
1622         struct btrfs_path *path;
1623         struct extent_buffer *leaf;
1624         struct btrfs_key ins;
1625         u64 hint;
1626         int ret;
1627
1628         path = btrfs_alloc_path();
1629         BUG_ON(!path);
1630
1631         path->leave_spinning = 1;
1632
1633         /*
1634          * we may be replacing one extent in the tree with another.
1635          * The new extent is pinned in the extent map, and we don't want
1636          * to drop it from the cache until it is completely in the btree.
1637          *
1638          * So, tell btrfs_drop_extents to leave this extent in the cache.
1639          * the caller is expected to unpin it and allow it to be merged
1640          * with the others.
1641          */
1642         ret = btrfs_drop_extents(trans, inode, file_pos, file_pos + num_bytes,
1643                                  &hint, 0);
1644         BUG_ON(ret);
1645
1646         ins.objectid = inode->i_ino;
1647         ins.offset = file_pos;
1648         ins.type = BTRFS_EXTENT_DATA_KEY;
1649         ret = btrfs_insert_empty_item(trans, root, path, &ins, sizeof(*fi));
1650         BUG_ON(ret);
1651         leaf = path->nodes[0];
1652         fi = btrfs_item_ptr(leaf, path->slots[0],
1653                             struct btrfs_file_extent_item);
1654         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1655         btrfs_set_file_extent_type(leaf, fi, extent_type);
1656         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
1657         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
1658         btrfs_set_file_extent_offset(leaf, fi, 0);
1659         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
1660         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
1661         btrfs_set_file_extent_compression(leaf, fi, compression);
1662         btrfs_set_file_extent_encryption(leaf, fi, encryption);
1663         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
1664
1665         btrfs_unlock_up_safe(path, 1);
1666         btrfs_set_lock_blocking(leaf);
1667
1668         btrfs_mark_buffer_dirty(leaf);
1669
1670         inode_add_bytes(inode, num_bytes);
1671
1672         ins.objectid = disk_bytenr;
1673         ins.offset = disk_num_bytes;
1674         ins.type = BTRFS_EXTENT_ITEM_KEY;
1675         ret = btrfs_alloc_reserved_file_extent(trans, root,
1676                                         root->root_key.objectid,
1677                                         inode->i_ino, file_pos, &ins);
1678         BUG_ON(ret);
1679         btrfs_free_path(path);
1680
1681         return 0;
1682 }
1683
1684 /*
1685  * helper function for btrfs_finish_ordered_io, this
1686  * just reads in some of the csum leaves to prime them into ram
1687  * before we start the transaction.  It limits the amount of btree
1688  * reads required while inside the transaction.
1689  */
1690 /* as ordered data IO finishes, this gets called so we can finish
1691  * an ordered extent if the range of bytes in the file it covers are
1692  * fully written.
1693  */
1694 static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
1695 {
1696         struct btrfs_root *root = BTRFS_I(inode)->root;
1697         struct btrfs_trans_handle *trans = NULL;
1698         struct btrfs_ordered_extent *ordered_extent = NULL;
1699         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1700         struct extent_state *cached_state = NULL;
1701         int compress_type = 0;
1702         int ret;
1703         bool nolock = false;
1704
1705         ret = btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
1706                                              end - start + 1);
1707         if (!ret)
1708                 return 0;
1709         BUG_ON(!ordered_extent);
1710
1711         nolock = (root == root->fs_info->tree_root);
1712
1713         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
1714                 BUG_ON(!list_empty(&ordered_extent->list));
1715                 ret = btrfs_ordered_update_i_size(inode, 0, ordered_extent);
1716                 if (!ret) {
1717                         if (nolock)
1718                                 trans = btrfs_join_transaction_nolock(root, 1);
1719                         else
1720                                 trans = btrfs_join_transaction(root, 1);
1721                         BUG_ON(IS_ERR(trans));
1722                         btrfs_set_trans_block_group(trans, inode);
1723                         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1724                         ret = btrfs_update_inode(trans, root, inode);
1725                         BUG_ON(ret);
1726                 }
1727                 goto out;
1728         }
1729
1730         lock_extent_bits(io_tree, ordered_extent->file_offset,
1731                          ordered_extent->file_offset + ordered_extent->len - 1,
1732                          0, &cached_state, GFP_NOFS);
1733
1734         if (nolock)
1735                 trans = btrfs_join_transaction_nolock(root, 1);
1736         else
1737                 trans = btrfs_join_transaction(root, 1);
1738         BUG_ON(IS_ERR(trans));
1739         btrfs_set_trans_block_group(trans, inode);
1740         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1741
1742         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
1743                 compress_type = ordered_extent->compress_type;
1744         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
1745                 BUG_ON(compress_type);
1746                 ret = btrfs_mark_extent_written(trans, inode,
1747                                                 ordered_extent->file_offset,
1748                                                 ordered_extent->file_offset +
1749                                                 ordered_extent->len);
1750                 BUG_ON(ret);
1751         } else {
1752                 BUG_ON(root == root->fs_info->tree_root);
1753                 ret = insert_reserved_file_extent(trans, inode,
1754                                                 ordered_extent->file_offset,
1755                                                 ordered_extent->start,
1756                                                 ordered_extent->disk_len,
1757                                                 ordered_extent->len,
1758                                                 ordered_extent->len,
1759                                                 compress_type, 0, 0,
1760                                                 BTRFS_FILE_EXTENT_REG);
1761                 unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
1762                                    ordered_extent->file_offset,
1763                                    ordered_extent->len);
1764                 BUG_ON(ret);
1765         }
1766         unlock_extent_cached(io_tree, ordered_extent->file_offset,
1767                              ordered_extent->file_offset +
1768                              ordered_extent->len - 1, &cached_state, GFP_NOFS);
1769
1770         add_pending_csums(trans, inode, ordered_extent->file_offset,
1771                           &ordered_extent->list);
1772
1773         ret = btrfs_ordered_update_i_size(inode, 0, ordered_extent);
1774         if (!ret) {
1775                 ret = btrfs_update_inode(trans, root, inode);
1776                 BUG_ON(ret);
1777         }
1778         ret = 0;
1779 out:
1780         if (nolock) {
1781                 if (trans)
1782                         btrfs_end_transaction_nolock(trans, root);
1783         } else {
1784                 btrfs_delalloc_release_metadata(inode, ordered_extent->len);
1785                 if (trans)
1786                         btrfs_end_transaction(trans, root);
1787         }
1788
1789         /* once for us */
1790         btrfs_put_ordered_extent(ordered_extent);
1791         /* once for the tree */
1792         btrfs_put_ordered_extent(ordered_extent);
1793
1794         return 0;
1795 }
1796
1797 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
1798                                 struct extent_state *state, int uptodate)
1799 {
1800         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
1801
1802         ClearPagePrivate2(page);
1803         return btrfs_finish_ordered_io(page->mapping->host, start, end);
1804 }
1805
1806 /*
1807  * When IO fails, either with EIO or csum verification fails, we
1808  * try other mirrors that might have a good copy of the data.  This
1809  * io_failure_record is used to record state as we go through all the
1810  * mirrors.  If another mirror has good data, the page is set up to date
1811  * and things continue.  If a good mirror can't be found, the original
1812  * bio end_io callback is called to indicate things have failed.
1813  */
1814 struct io_failure_record {
1815         struct page *page;
1816         u64 start;
1817         u64 len;
1818         u64 logical;
1819         unsigned long bio_flags;
1820         int last_mirror;
1821 };
1822
1823 static int btrfs_io_failed_hook(struct bio *failed_bio,
1824                          struct page *page, u64 start, u64 end,
1825                          struct extent_state *state)
1826 {
1827         struct io_failure_record *failrec = NULL;
1828         u64 private;
1829         struct extent_map *em;
1830         struct inode *inode = page->mapping->host;
1831         struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
1832         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
1833         struct bio *bio;
1834         int num_copies;
1835         int ret;
1836         int rw;
1837         u64 logical;
1838
1839         ret = get_state_private(failure_tree, start, &private);
1840         if (ret) {
1841                 failrec = kmalloc(sizeof(*failrec), GFP_NOFS);
1842                 if (!failrec)
1843                         return -ENOMEM;
1844                 failrec->start = start;
1845                 failrec->len = end - start + 1;
1846                 failrec->last_mirror = 0;
1847                 failrec->bio_flags = 0;
1848
1849                 read_lock(&em_tree->lock);
1850                 em = lookup_extent_mapping(em_tree, start, failrec->len);
1851                 if (em->start > start || em->start + em->len < start) {
1852                         free_extent_map(em);
1853                         em = NULL;
1854                 }
1855                 read_unlock(&em_tree->lock);
1856
1857                 if (!em || IS_ERR(em)) {
1858                         kfree(failrec);
1859                         return -EIO;
1860                 }
1861                 logical = start - em->start;
1862                 logical = em->block_start + logical;
1863                 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
1864                         logical = em->block_start;
1865                         failrec->bio_flags = EXTENT_BIO_COMPRESSED;
1866                         extent_set_compress_type(&failrec->bio_flags,
1867                                                  em->compress_type);
1868                 }
1869                 failrec->logical = logical;
1870                 free_extent_map(em);
1871                 set_extent_bits(failure_tree, start, end, EXTENT_LOCKED |
1872                                 EXTENT_DIRTY, GFP_NOFS);
1873                 set_state_private(failure_tree, start,
1874                                  (u64)(unsigned long)failrec);
1875         } else {
1876                 failrec = (struct io_failure_record *)(unsigned long)private;
1877         }
1878         num_copies = btrfs_num_copies(
1879                               &BTRFS_I(inode)->root->fs_info->mapping_tree,
1880                               failrec->logical, failrec->len);
1881         failrec->last_mirror++;
1882         if (!state) {
1883                 spin_lock(&BTRFS_I(inode)->io_tree.lock);
1884                 state = find_first_extent_bit_state(&BTRFS_I(inode)->io_tree,
1885                                                     failrec->start,
1886                                                     EXTENT_LOCKED);
1887                 if (state && state->start != failrec->start)
1888                         state = NULL;
1889                 spin_unlock(&BTRFS_I(inode)->io_tree.lock);
1890         }
1891         if (!state || failrec->last_mirror > num_copies) {
1892                 set_state_private(failure_tree, failrec->start, 0);
1893                 clear_extent_bits(failure_tree, failrec->start,
1894                                   failrec->start + failrec->len - 1,
1895                                   EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
1896                 kfree(failrec);
1897                 return -EIO;
1898         }
1899         bio = bio_alloc(GFP_NOFS, 1);
1900         bio->bi_private = state;
1901         bio->bi_end_io = failed_bio->bi_end_io;
1902         bio->bi_sector = failrec->logical >> 9;
1903         bio->bi_bdev = failed_bio->bi_bdev;
1904         bio->bi_size = 0;
1905
1906         bio_add_page(bio, page, failrec->len, start - page_offset(page));
1907         if (failed_bio->bi_rw & REQ_WRITE)
1908                 rw = WRITE;
1909         else
1910                 rw = READ;
1911
1912         ret = BTRFS_I(inode)->io_tree.ops->submit_bio_hook(inode, rw, bio,
1913                                                       failrec->last_mirror,
1914                                                       failrec->bio_flags, 0);
1915         return ret;
1916 }
1917
1918 /*
1919  * each time an IO finishes, we do a fast check in the IO failure tree
1920  * to see if we need to process or clean up an io_failure_record
1921  */
1922 static int btrfs_clean_io_failures(struct inode *inode, u64 start)
1923 {
1924         u64 private;
1925         u64 private_failure;
1926         struct io_failure_record *failure;
1927         int ret;
1928
1929         private = 0;
1930         if (count_range_bits(&BTRFS_I(inode)->io_failure_tree, &private,
1931                              (u64)-1, 1, EXTENT_DIRTY, 0)) {
1932                 ret = get_state_private(&BTRFS_I(inode)->io_failure_tree,
1933                                         start, &private_failure);
1934                 if (ret == 0) {
1935                         failure = (struct io_failure_record *)(unsigned long)
1936                                    private_failure;
1937                         set_state_private(&BTRFS_I(inode)->io_failure_tree,
1938                                           failure->start, 0);
1939                         clear_extent_bits(&BTRFS_I(inode)->io_failure_tree,
1940                                           failure->start,
1941                                           failure->start + failure->len - 1,
1942                                           EXTENT_DIRTY | EXTENT_LOCKED,
1943                                           GFP_NOFS);
1944                         kfree(failure);
1945                 }
1946         }
1947         return 0;
1948 }
1949
1950 /*
1951  * when reads are done, we need to check csums to verify the data is correct
1952  * if there's a match, we allow the bio to finish.  If not, we go through
1953  * the io_failure_record routines to find good copies
1954  */
1955 static int btrfs_readpage_end_io_hook(struct page *page, u64 start, u64 end,
1956                                struct extent_state *state)
1957 {
1958         size_t offset = start - ((u64)page->index << PAGE_CACHE_SHIFT);
1959         struct inode *inode = page->mapping->host;
1960         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1961         char *kaddr;
1962         u64 private = ~(u32)0;
1963         int ret;
1964         struct btrfs_root *root = BTRFS_I(inode)->root;
1965         u32 csum = ~(u32)0;
1966
1967         if (PageChecked(page)) {
1968                 ClearPageChecked(page);
1969                 goto good;
1970         }
1971
1972         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
1973                 return 0;
1974
1975         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
1976             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
1977                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
1978                                   GFP_NOFS);
1979                 return 0;
1980         }
1981
1982         if (state && state->start == start) {
1983                 private = state->private;
1984                 ret = 0;
1985         } else {
1986                 ret = get_state_private(io_tree, start, &private);
1987         }
1988         kaddr = kmap_atomic(page, KM_USER0);
1989         if (ret)
1990                 goto zeroit;
1991
1992         csum = btrfs_csum_data(root, kaddr + offset, csum,  end - start + 1);
1993         btrfs_csum_final(csum, (char *)&csum);
1994         if (csum != private)
1995                 goto zeroit;
1996
1997         kunmap_atomic(kaddr, KM_USER0);
1998 good:
1999         /* if the io failure tree for this inode is non-empty,
2000          * check to see if we've recovered from a failed IO
2001          */
2002         btrfs_clean_io_failures(inode, start);
2003         return 0;
2004
2005 zeroit:
2006         if (printk_ratelimit()) {
2007                 printk(KERN_INFO "btrfs csum failed ino %lu off %llu csum %u "
2008                        "private %llu\n", page->mapping->host->i_ino,
2009                        (unsigned long long)start, csum,
2010                        (unsigned long long)private);
2011         }
2012         memset(kaddr + offset, 1, end - start + 1);
2013         flush_dcache_page(page);
2014         kunmap_atomic(kaddr, KM_USER0);
2015         if (private == 0)
2016                 return 0;
2017         return -EIO;
2018 }
2019
2020 struct delayed_iput {
2021         struct list_head list;
2022         struct inode *inode;
2023 };
2024
2025 void btrfs_add_delayed_iput(struct inode *inode)
2026 {
2027         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2028         struct delayed_iput *delayed;
2029
2030         if (atomic_add_unless(&inode->i_count, -1, 1))
2031                 return;
2032
2033         delayed = kmalloc(sizeof(*delayed), GFP_NOFS | __GFP_NOFAIL);
2034         delayed->inode = inode;
2035
2036         spin_lock(&fs_info->delayed_iput_lock);
2037         list_add_tail(&delayed->list, &fs_info->delayed_iputs);
2038         spin_unlock(&fs_info->delayed_iput_lock);
2039 }
2040
2041 void btrfs_run_delayed_iputs(struct btrfs_root *root)
2042 {
2043         LIST_HEAD(list);
2044         struct btrfs_fs_info *fs_info = root->fs_info;
2045         struct delayed_iput *delayed;
2046         int empty;
2047
2048         spin_lock(&fs_info->delayed_iput_lock);
2049         empty = list_empty(&fs_info->delayed_iputs);
2050         spin_unlock(&fs_info->delayed_iput_lock);
2051         if (empty)
2052                 return;
2053
2054         down_read(&root->fs_info->cleanup_work_sem);
2055         spin_lock(&fs_info->delayed_iput_lock);
2056         list_splice_init(&fs_info->delayed_iputs, &list);
2057         spin_unlock(&fs_info->delayed_iput_lock);
2058
2059         while (!list_empty(&list)) {
2060                 delayed = list_entry(list.next, struct delayed_iput, list);
2061                 list_del(&delayed->list);
2062                 iput(delayed->inode);
2063                 kfree(delayed);
2064         }
2065         up_read(&root->fs_info->cleanup_work_sem);
2066 }
2067
2068 /*
2069  * calculate extra metadata reservation when snapshotting a subvolume
2070  * contains orphan files.
2071  */
2072 void btrfs_orphan_pre_snapshot(struct btrfs_trans_handle *trans,
2073                                 struct btrfs_pending_snapshot *pending,
2074                                 u64 *bytes_to_reserve)
2075 {
2076         struct btrfs_root *root;
2077         struct btrfs_block_rsv *block_rsv;
2078         u64 num_bytes;
2079         int index;
2080
2081         root = pending->root;
2082         if (!root->orphan_block_rsv || list_empty(&root->orphan_list))
2083                 return;
2084
2085         block_rsv = root->orphan_block_rsv;
2086
2087         /* orphan block reservation for the snapshot */
2088         num_bytes = block_rsv->size;
2089
2090         /*
2091          * after the snapshot is created, COWing tree blocks may use more
2092          * space than it frees. So we should make sure there is enough
2093          * reserved space.
2094          */
2095         index = trans->transid & 0x1;
2096         if (block_rsv->reserved + block_rsv->freed[index] < block_rsv->size) {
2097                 num_bytes += block_rsv->size -
2098                              (block_rsv->reserved + block_rsv->freed[index]);
2099         }
2100
2101         *bytes_to_reserve += num_bytes;
2102 }
2103
2104 void btrfs_orphan_post_snapshot(struct btrfs_trans_handle *trans,
2105                                 struct btrfs_pending_snapshot *pending)
2106 {
2107         struct btrfs_root *root = pending->root;
2108         struct btrfs_root *snap = pending->snap;
2109         struct btrfs_block_rsv *block_rsv;
2110         u64 num_bytes;
2111         int index;
2112         int ret;
2113
2114         if (!root->orphan_block_rsv || list_empty(&root->orphan_list))
2115                 return;
2116
2117         /* refill source subvolume's orphan block reservation */
2118         block_rsv = root->orphan_block_rsv;
2119         index = trans->transid & 0x1;
2120         if (block_rsv->reserved + block_rsv->freed[index] < block_rsv->size) {
2121                 num_bytes = block_rsv->size -
2122                             (block_rsv->reserved + block_rsv->freed[index]);
2123                 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
2124                                               root->orphan_block_rsv,
2125                                               num_bytes);
2126                 BUG_ON(ret);
2127         }
2128
2129         /* setup orphan block reservation for the snapshot */
2130         block_rsv = btrfs_alloc_block_rsv(snap);
2131         BUG_ON(!block_rsv);
2132
2133         btrfs_add_durable_block_rsv(root->fs_info, block_rsv);
2134         snap->orphan_block_rsv = block_rsv;
2135
2136         num_bytes = root->orphan_block_rsv->size;
2137         ret = btrfs_block_rsv_migrate(&pending->block_rsv,
2138                                       block_rsv, num_bytes);
2139         BUG_ON(ret);
2140
2141 #if 0
2142         /* insert orphan item for the snapshot */
2143         WARN_ON(!root->orphan_item_inserted);
2144         ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
2145                                        snap->root_key.objectid);
2146         BUG_ON(ret);
2147         snap->orphan_item_inserted = 1;
2148 #endif
2149 }
2150
2151 enum btrfs_orphan_cleanup_state {
2152         ORPHAN_CLEANUP_STARTED  = 1,
2153         ORPHAN_CLEANUP_DONE     = 2,
2154 };
2155
2156 /*
2157  * This is called in transaction commmit time. If there are no orphan
2158  * files in the subvolume, it removes orphan item and frees block_rsv
2159  * structure.
2160  */
2161 void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
2162                               struct btrfs_root *root)
2163 {
2164         int ret;
2165
2166         if (!list_empty(&root->orphan_list) ||
2167             root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE)
2168                 return;
2169
2170         if (root->orphan_item_inserted &&
2171             btrfs_root_refs(&root->root_item) > 0) {
2172                 ret = btrfs_del_orphan_item(trans, root->fs_info->tree_root,
2173                                             root->root_key.objectid);
2174                 BUG_ON(ret);
2175                 root->orphan_item_inserted = 0;
2176         }
2177
2178         if (root->orphan_block_rsv) {
2179                 WARN_ON(root->orphan_block_rsv->size > 0);
2180                 btrfs_free_block_rsv(root, root->orphan_block_rsv);
2181                 root->orphan_block_rsv = NULL;
2182         }
2183 }
2184
2185 /*
2186  * This creates an orphan entry for the given inode in case something goes
2187  * wrong in the middle of an unlink/truncate.
2188  *
2189  * NOTE: caller of this function should reserve 5 units of metadata for
2190  *       this function.
2191  */
2192 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
2193 {
2194         struct btrfs_root *root = BTRFS_I(inode)->root;
2195         struct btrfs_block_rsv *block_rsv = NULL;
2196         int reserve = 0;
2197         int insert = 0;
2198         int ret;
2199
2200         if (!root->orphan_block_rsv) {
2201                 block_rsv = btrfs_alloc_block_rsv(root);
2202                 BUG_ON(!block_rsv);
2203         }
2204
2205         spin_lock(&root->orphan_lock);
2206         if (!root->orphan_block_rsv) {
2207                 root->orphan_block_rsv = block_rsv;
2208         } else if (block_rsv) {
2209                 btrfs_free_block_rsv(root, block_rsv);
2210                 block_rsv = NULL;
2211         }
2212
2213         if (list_empty(&BTRFS_I(inode)->i_orphan)) {
2214                 list_add(&BTRFS_I(inode)->i_orphan, &root->orphan_list);
2215 #if 0
2216                 /*
2217                  * For proper ENOSPC handling, we should do orphan
2218                  * cleanup when mounting. But this introduces backward
2219                  * compatibility issue.
2220                  */
2221                 if (!xchg(&root->orphan_item_inserted, 1))
2222                         insert = 2;
2223                 else
2224                         insert = 1;
2225 #endif
2226                 insert = 1;
2227         }
2228
2229         if (!BTRFS_I(inode)->orphan_meta_reserved) {
2230                 BTRFS_I(inode)->orphan_meta_reserved = 1;
2231                 reserve = 1;
2232         }
2233         spin_unlock(&root->orphan_lock);
2234
2235         if (block_rsv)
2236                 btrfs_add_durable_block_rsv(root->fs_info, block_rsv);
2237
2238         /* grab metadata reservation from transaction handle */
2239         if (reserve) {
2240                 ret = btrfs_orphan_reserve_metadata(trans, inode);
2241                 BUG_ON(ret);
2242         }
2243
2244         /* insert an orphan item to track this unlinked/truncated file */
2245         if (insert >= 1) {
2246                 ret = btrfs_insert_orphan_item(trans, root, inode->i_ino);
2247                 BUG_ON(ret);
2248         }
2249
2250         /* insert an orphan item to track subvolume contains orphan files */
2251         if (insert >= 2) {
2252                 ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
2253                                                root->root_key.objectid);
2254                 BUG_ON(ret);
2255         }
2256         return 0;
2257 }
2258
2259 /*
2260  * We have done the truncate/delete so we can go ahead and remove the orphan
2261  * item for this particular inode.
2262  */
2263 int btrfs_orphan_del(struct btrfs_trans_handle *trans, struct inode *inode)
2264 {
2265         struct btrfs_root *root = BTRFS_I(inode)->root;
2266         int delete_item = 0;
2267         int release_rsv = 0;
2268         int ret = 0;
2269
2270         spin_lock(&root->orphan_lock);
2271         if (!list_empty(&BTRFS_I(inode)->i_orphan)) {
2272                 list_del_init(&BTRFS_I(inode)->i_orphan);
2273                 delete_item = 1;
2274         }
2275
2276         if (BTRFS_I(inode)->orphan_meta_reserved) {
2277                 BTRFS_I(inode)->orphan_meta_reserved = 0;
2278                 release_rsv = 1;
2279         }
2280         spin_unlock(&root->orphan_lock);
2281
2282         if (trans && delete_item) {
2283                 ret = btrfs_del_orphan_item(trans, root, inode->i_ino);
2284                 BUG_ON(ret);
2285         }
2286
2287         if (release_rsv)
2288                 btrfs_orphan_release_metadata(inode);
2289
2290         return 0;
2291 }
2292
2293 /*
2294  * this cleans up any orphans that may be left on the list from the last use
2295  * of this root.
2296  */
2297 int btrfs_orphan_cleanup(struct btrfs_root *root)
2298 {
2299         struct btrfs_path *path;
2300         struct extent_buffer *leaf;
2301         struct btrfs_key key, found_key;
2302         struct btrfs_trans_handle *trans;
2303         struct inode *inode;
2304         int ret = 0, nr_unlink = 0, nr_truncate = 0;
2305
2306         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
2307                 return 0;
2308
2309         path = btrfs_alloc_path();
2310         if (!path) {
2311                 ret = -ENOMEM;
2312                 goto out;
2313         }
2314         path->reada = -1;
2315
2316         key.objectid = BTRFS_ORPHAN_OBJECTID;
2317         btrfs_set_key_type(&key, BTRFS_ORPHAN_ITEM_KEY);
2318         key.offset = (u64)-1;
2319
2320         while (1) {
2321                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2322                 if (ret < 0)
2323                         goto out;
2324
2325                 /*
2326                  * if ret == 0 means we found what we were searching for, which
2327                  * is weird, but possible, so only screw with path if we didnt
2328                  * find the key and see if we have stuff that matches
2329                  */
2330                 if (ret > 0) {
2331                         ret = 0;
2332                         if (path->slots[0] == 0)
2333                                 break;
2334                         path->slots[0]--;
2335                 }
2336
2337                 /* pull out the item */
2338                 leaf = path->nodes[0];
2339                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2340
2341                 /* make sure the item matches what we want */
2342                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
2343                         break;
2344                 if (btrfs_key_type(&found_key) != BTRFS_ORPHAN_ITEM_KEY)
2345                         break;
2346
2347                 /* release the path since we're done with it */
2348                 btrfs_release_path(root, path);
2349
2350                 /*
2351                  * this is where we are basically btrfs_lookup, without the
2352                  * crossing root thing.  we store the inode number in the
2353                  * offset of the orphan item.
2354                  */
2355                 found_key.objectid = found_key.offset;
2356                 found_key.type = BTRFS_INODE_ITEM_KEY;
2357                 found_key.offset = 0;
2358                 inode = btrfs_iget(root->fs_info->sb, &found_key, root, NULL);
2359                 if (IS_ERR(inode)) {
2360                         ret = PTR_ERR(inode);
2361                         goto out;
2362                 }
2363
2364                 /*
2365                  * add this inode to the orphan list so btrfs_orphan_del does
2366                  * the proper thing when we hit it
2367                  */
2368                 spin_lock(&root->orphan_lock);
2369                 list_add(&BTRFS_I(inode)->i_orphan, &root->orphan_list);
2370                 spin_unlock(&root->orphan_lock);
2371
2372                 /*
2373                  * if this is a bad inode, means we actually succeeded in
2374                  * removing the inode, but not the orphan record, which means
2375                  * we need to manually delete the orphan since iput will just
2376                  * do a destroy_inode
2377                  */
2378                 if (is_bad_inode(inode)) {
2379                         trans = btrfs_start_transaction(root, 0);
2380                         if (IS_ERR(trans)) {
2381                                 ret = PTR_ERR(trans);
2382                                 goto out;
2383                         }
2384                         btrfs_orphan_del(trans, inode);
2385                         btrfs_end_transaction(trans, root);
2386                         iput(inode);
2387                         continue;
2388                 }
2389
2390                 /* if we have links, this was a truncate, lets do that */
2391                 if (inode->i_nlink) {
2392                         if (!S_ISREG(inode->i_mode)) {
2393                                 WARN_ON(1);
2394                                 iput(inode);
2395                                 continue;
2396                         }
2397                         nr_truncate++;
2398                         ret = btrfs_truncate(inode);
2399                 } else {
2400                         nr_unlink++;
2401                 }
2402
2403                 /* this will do delete_inode and everything for us */
2404                 iput(inode);
2405                 if (ret)
2406                         goto out;
2407         }
2408         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
2409
2410         if (root->orphan_block_rsv)
2411                 btrfs_block_rsv_release(root, root->orphan_block_rsv,
2412                                         (u64)-1);
2413
2414         if (root->orphan_block_rsv || root->orphan_item_inserted) {
2415                 trans = btrfs_join_transaction(root, 1);
2416                 if (!IS_ERR(trans))
2417                         btrfs_end_transaction(trans, root);
2418         }
2419
2420         if (nr_unlink)
2421                 printk(KERN_INFO "btrfs: unlinked %d orphans\n", nr_unlink);
2422         if (nr_truncate)
2423                 printk(KERN_INFO "btrfs: truncated %d orphans\n", nr_truncate);
2424
2425 out:
2426         if (ret)
2427                 printk(KERN_CRIT "btrfs: could not do orphan cleanup %d\n", ret);
2428         btrfs_free_path(path);
2429         return ret;
2430 }
2431
2432 /*
2433  * very simple check to peek ahead in the leaf looking for xattrs.  If we
2434  * don't find any xattrs, we know there can't be any acls.
2435  *
2436  * slot is the slot the inode is in, objectid is the objectid of the inode
2437  */
2438 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
2439                                           int slot, u64 objectid)
2440 {
2441         u32 nritems = btrfs_header_nritems(leaf);
2442         struct btrfs_key found_key;
2443         int scanned = 0;
2444
2445         slot++;
2446         while (slot < nritems) {
2447                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2448
2449                 /* we found a different objectid, there must not be acls */
2450                 if (found_key.objectid != objectid)
2451                         return 0;
2452
2453                 /* we found an xattr, assume we've got an acl */
2454                 if (found_key.type == BTRFS_XATTR_ITEM_KEY)
2455                         return 1;
2456
2457                 /*
2458                  * we found a key greater than an xattr key, there can't
2459                  * be any acls later on
2460                  */
2461                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
2462                         return 0;
2463
2464                 slot++;
2465                 scanned++;
2466
2467                 /*
2468                  * it goes inode, inode backrefs, xattrs, extents,
2469                  * so if there are a ton of hard links to an inode there can
2470                  * be a lot of backrefs.  Don't waste time searching too hard,
2471                  * this is just an optimization
2472                  */
2473                 if (scanned >= 8)
2474                         break;
2475         }
2476         /* we hit the end of the leaf before we found an xattr or
2477          * something larger than an xattr.  We have to assume the inode
2478          * has acls
2479          */
2480         return 1;
2481 }
2482
2483 /*
2484  * read an inode from the btree into the in-memory inode
2485  */
2486 static void btrfs_read_locked_inode(struct inode *inode)
2487 {
2488         struct btrfs_path *path;
2489         struct extent_buffer *leaf;
2490         struct btrfs_inode_item *inode_item;
2491         struct btrfs_timespec *tspec;
2492         struct btrfs_root *root = BTRFS_I(inode)->root;
2493         struct btrfs_key location;
2494         int maybe_acls;
2495         u64 alloc_group_block;
2496         u32 rdev;
2497         int ret;
2498
2499         path = btrfs_alloc_path();
2500         BUG_ON(!path);
2501         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
2502
2503         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
2504         if (ret)
2505                 goto make_bad;
2506
2507         leaf = path->nodes[0];
2508         inode_item = btrfs_item_ptr(leaf, path->slots[0],
2509                                     struct btrfs_inode_item);
2510
2511         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
2512         inode->i_nlink = btrfs_inode_nlink(leaf, inode_item);
2513         inode->i_uid = btrfs_inode_uid(leaf, inode_item);
2514         inode->i_gid = btrfs_inode_gid(leaf, inode_item);
2515         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
2516
2517         tspec = btrfs_inode_atime(inode_item);
2518         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2519         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2520
2521         tspec = btrfs_inode_mtime(inode_item);
2522         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2523         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2524
2525         tspec = btrfs_inode_ctime(inode_item);
2526         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2527         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2528
2529         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
2530         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
2531         BTRFS_I(inode)->sequence = btrfs_inode_sequence(leaf, inode_item);
2532         inode->i_generation = BTRFS_I(inode)->generation;
2533         inode->i_rdev = 0;
2534         rdev = btrfs_inode_rdev(leaf, inode_item);
2535
2536         BTRFS_I(inode)->index_cnt = (u64)-1;
2537         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
2538
2539         alloc_group_block = btrfs_inode_block_group(leaf, inode_item);
2540
2541         /*
2542          * try to precache a NULL acl entry for files that don't have
2543          * any xattrs or acls
2544          */
2545         maybe_acls = acls_after_inode_item(leaf, path->slots[0], inode->i_ino);
2546         if (!maybe_acls)
2547                 cache_no_acl(inode);
2548
2549         BTRFS_I(inode)->block_group = btrfs_find_block_group(root, 0,
2550                                                 alloc_group_block, 0);
2551         btrfs_free_path(path);
2552         inode_item = NULL;
2553
2554         switch (inode->i_mode & S_IFMT) {
2555         case S_IFREG:
2556                 inode->i_mapping->a_ops = &btrfs_aops;
2557                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
2558                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
2559                 inode->i_fop = &btrfs_file_operations;
2560                 inode->i_op = &btrfs_file_inode_operations;
2561                 break;
2562         case S_IFDIR:
2563                 inode->i_fop = &btrfs_dir_file_operations;
2564                 if (root == root->fs_info->tree_root)
2565                         inode->i_op = &btrfs_dir_ro_inode_operations;
2566                 else
2567                         inode->i_op = &btrfs_dir_inode_operations;
2568                 break;
2569         case S_IFLNK:
2570                 inode->i_op = &btrfs_symlink_inode_operations;
2571                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
2572                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
2573                 break;
2574         default:
2575                 inode->i_op = &btrfs_special_inode_operations;
2576                 init_special_inode(inode, inode->i_mode, rdev);
2577                 break;
2578         }
2579
2580         btrfs_update_iflags(inode);
2581         return;
2582
2583 make_bad:
2584         btrfs_free_path(path);
2585         make_bad_inode(inode);
2586 }
2587
2588 /*
2589  * given a leaf and an inode, copy the inode fields into the leaf
2590  */
2591 static void fill_inode_item(struct btrfs_trans_handle *trans,
2592                             struct extent_buffer *leaf,
2593                             struct btrfs_inode_item *item,
2594                             struct inode *inode)
2595 {
2596         if (!leaf->map_token)
2597                 map_private_extent_buffer(leaf, (unsigned long)item,
2598                                           sizeof(struct btrfs_inode_item),
2599                                           &leaf->map_token, &leaf->kaddr,
2600                                           &leaf->map_start, &leaf->map_len,
2601                                           KM_USER1);
2602
2603         btrfs_set_inode_uid(leaf, item, inode->i_uid);
2604         btrfs_set_inode_gid(leaf, item, inode->i_gid);
2605         btrfs_set_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size);
2606         btrfs_set_inode_mode(leaf, item, inode->i_mode);
2607         btrfs_set_inode_nlink(leaf, item, inode->i_nlink);
2608
2609         btrfs_set_timespec_sec(leaf, btrfs_inode_atime(item),
2610                                inode->i_atime.tv_sec);
2611         btrfs_set_timespec_nsec(leaf, btrfs_inode_atime(item),
2612                                 inode->i_atime.tv_nsec);
2613
2614         btrfs_set_timespec_sec(leaf, btrfs_inode_mtime(item),
2615                                inode->i_mtime.tv_sec);
2616         btrfs_set_timespec_nsec(leaf, btrfs_inode_mtime(item),
2617                                 inode->i_mtime.tv_nsec);
2618
2619         btrfs_set_timespec_sec(leaf, btrfs_inode_ctime(item),
2620                                inode->i_ctime.tv_sec);
2621         btrfs_set_timespec_nsec(leaf, btrfs_inode_ctime(item),
2622                                 inode->i_ctime.tv_nsec);
2623
2624         btrfs_set_inode_nbytes(leaf, item, inode_get_bytes(inode));
2625         btrfs_set_inode_generation(leaf, item, BTRFS_I(inode)->generation);
2626         btrfs_set_inode_sequence(leaf, item, BTRFS_I(inode)->sequence);
2627         btrfs_set_inode_transid(leaf, item, trans->transid);
2628         btrfs_set_inode_rdev(leaf, item, inode->i_rdev);
2629         btrfs_set_inode_flags(leaf, item, BTRFS_I(inode)->flags);
2630         btrfs_set_inode_block_group(leaf, item, BTRFS_I(inode)->block_group);
2631
2632         if (leaf->map_token) {
2633                 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2634                 leaf->map_token = NULL;
2635         }
2636 }
2637
2638 /*
2639  * copy everything in the in-memory inode into the btree.
2640  */
2641 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
2642                                 struct btrfs_root *root, struct inode *inode)
2643 {
2644         struct btrfs_inode_item *inode_item;
2645         struct btrfs_path *path;
2646         struct extent_buffer *leaf;
2647         int ret;
2648
2649         path = btrfs_alloc_path();
2650         BUG_ON(!path);
2651         path->leave_spinning = 1;
2652         ret = btrfs_lookup_inode(trans, root, path,
2653                                  &BTRFS_I(inode)->location, 1);
2654         if (ret) {
2655                 if (ret > 0)
2656                         ret = -ENOENT;
2657                 goto failed;
2658         }
2659
2660         btrfs_unlock_up_safe(path, 1);
2661         leaf = path->nodes[0];
2662         inode_item = btrfs_item_ptr(leaf, path->slots[0],
2663                                   struct btrfs_inode_item);
2664
2665         fill_inode_item(trans, leaf, inode_item, inode);
2666         btrfs_mark_buffer_dirty(leaf);
2667         btrfs_set_inode_last_trans(trans, inode);
2668         ret = 0;
2669 failed:
2670         btrfs_free_path(path);
2671         return ret;
2672 }
2673
2674
2675 /*
2676  * unlink helper that gets used here in inode.c and in the tree logging
2677  * recovery code.  It remove a link in a directory with a given name, and
2678  * also drops the back refs in the inode to the directory
2679  */
2680 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
2681                                 struct btrfs_root *root,
2682                                 struct inode *dir, struct inode *inode,
2683                                 const char *name, int name_len)
2684 {
2685         struct btrfs_path *path;
2686         int ret = 0;
2687         struct extent_buffer *leaf;
2688         struct btrfs_dir_item *di;
2689         struct btrfs_key key;
2690         u64 index;
2691
2692         path = btrfs_alloc_path();
2693         if (!path) {
2694                 ret = -ENOMEM;
2695                 goto out;
2696         }
2697
2698         path->leave_spinning = 1;
2699         di = btrfs_lookup_dir_item(trans, root, path, dir->i_ino,
2700                                     name, name_len, -1);
2701         if (IS_ERR(di)) {
2702                 ret = PTR_ERR(di);
2703                 goto err;
2704         }
2705         if (!di) {
2706                 ret = -ENOENT;
2707                 goto err;
2708         }
2709         leaf = path->nodes[0];
2710         btrfs_dir_item_key_to_cpu(leaf, di, &key);
2711         ret = btrfs_delete_one_dir_name(trans, root, path, di);
2712         if (ret)
2713                 goto err;
2714         btrfs_release_path(root, path);
2715
2716         ret = btrfs_del_inode_ref(trans, root, name, name_len,
2717                                   inode->i_ino,
2718                                   dir->i_ino, &index);
2719         if (ret) {
2720                 printk(KERN_INFO "btrfs failed to delete reference to %.*s, "
2721                        "inode %lu parent %lu\n", name_len, name,
2722                        inode->i_ino, dir->i_ino);
2723                 goto err;
2724         }
2725
2726         di = btrfs_lookup_dir_index_item(trans, root, path, dir->i_ino,
2727                                          index, name, name_len, -1);
2728         if (IS_ERR(di)) {
2729                 ret = PTR_ERR(di);
2730                 goto err;
2731         }
2732         if (!di) {
2733                 ret = -ENOENT;
2734                 goto err;
2735         }
2736         ret = btrfs_delete_one_dir_name(trans, root, path, di);
2737         btrfs_release_path(root, path);
2738
2739         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
2740                                          inode, dir->i_ino);
2741         BUG_ON(ret != 0 && ret != -ENOENT);
2742
2743         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
2744                                            dir, index);
2745         if (ret == -ENOENT)
2746                 ret = 0;
2747 err:
2748         btrfs_free_path(path);
2749         if (ret)
2750                 goto out;
2751
2752         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
2753         inode->i_ctime = dir->i_mtime = dir->i_ctime = CURRENT_TIME;
2754         btrfs_update_inode(trans, root, dir);
2755 out:
2756         return ret;
2757 }
2758
2759 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
2760                        struct btrfs_root *root,
2761                        struct inode *dir, struct inode *inode,
2762                        const char *name, int name_len)
2763 {
2764         int ret;
2765         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
2766         if (!ret) {
2767                 btrfs_drop_nlink(inode);
2768                 ret = btrfs_update_inode(trans, root, inode);
2769         }
2770         return ret;
2771 }
2772
2773
2774 /* helper to check if there is any shared block in the path */
2775 static int check_path_shared(struct btrfs_root *root,
2776                              struct btrfs_path *path)
2777 {
2778         struct extent_buffer *eb;
2779         int level;
2780         u64 refs = 1;
2781
2782         for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2783                 int ret;
2784
2785                 if (!path->nodes[level])
2786                         break;
2787                 eb = path->nodes[level];
2788                 if (!btrfs_block_can_be_shared(root, eb))
2789                         continue;
2790                 ret = btrfs_lookup_extent_info(NULL, root, eb->start, eb->len,
2791                                                &refs, NULL);
2792                 if (refs > 1)
2793                         return 1;
2794         }
2795         return 0;
2796 }
2797
2798 /*
2799  * helper to start transaction for unlink and rmdir.
2800  *
2801  * unlink and rmdir are special in btrfs, they do not always free space.
2802  * so in enospc case, we should make sure they will free space before
2803  * allowing them to use the global metadata reservation.
2804  */
2805 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir,
2806                                                        struct dentry *dentry)
2807 {
2808         struct btrfs_trans_handle *trans;
2809         struct btrfs_root *root = BTRFS_I(dir)->root;
2810         struct btrfs_path *path;
2811         struct btrfs_inode_ref *ref;
2812         struct btrfs_dir_item *di;
2813         struct inode *inode = dentry->d_inode;
2814         u64 index;
2815         int check_link = 1;
2816         int err = -ENOSPC;
2817         int ret;
2818
2819         trans = btrfs_start_transaction(root, 10);
2820         if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
2821                 return trans;
2822
2823         if (inode->i_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
2824                 return ERR_PTR(-ENOSPC);
2825
2826         /* check if there is someone else holds reference */
2827         if (S_ISDIR(inode->i_mode) && atomic_read(&inode->i_count) > 1)
2828                 return ERR_PTR(-ENOSPC);
2829
2830         if (atomic_read(&inode->i_count) > 2)
2831                 return ERR_PTR(-ENOSPC);
2832
2833         if (xchg(&root->fs_info->enospc_unlink, 1))
2834                 return ERR_PTR(-ENOSPC);
2835
2836         path = btrfs_alloc_path();
2837         if (!path) {
2838                 root->fs_info->enospc_unlink = 0;
2839                 return ERR_PTR(-ENOMEM);
2840         }
2841
2842         trans = btrfs_start_transaction(root, 0);
2843         if (IS_ERR(trans)) {
2844                 btrfs_free_path(path);
2845                 root->fs_info->enospc_unlink = 0;
2846                 return trans;
2847         }
2848
2849         path->skip_locking = 1;
2850         path->search_commit_root = 1;
2851
2852         ret = btrfs_lookup_inode(trans, root, path,
2853                                 &BTRFS_I(dir)->location, 0);
2854         if (ret < 0) {
2855                 err = ret;
2856                 goto out;
2857         }
2858         if (ret == 0) {
2859                 if (check_path_shared(root, path))
2860                         goto out;
2861         } else {
2862                 check_link = 0;
2863         }
2864         btrfs_release_path(root, path);
2865
2866         ret = btrfs_lookup_inode(trans, root, path,
2867                                 &BTRFS_I(inode)->location, 0);
2868         if (ret < 0) {
2869                 err = ret;
2870                 goto out;
2871         }
2872         if (ret == 0) {
2873                 if (check_path_shared(root, path))
2874                         goto out;
2875         } else {
2876                 check_link = 0;
2877         }
2878         btrfs_release_path(root, path);
2879
2880         if (ret == 0 && S_ISREG(inode->i_mode)) {
2881                 ret = btrfs_lookup_file_extent(trans, root, path,
2882                                                inode->i_ino, (u64)-1, 0);
2883                 if (ret < 0) {
2884                         err = ret;
2885                         goto out;
2886                 }
2887                 BUG_ON(ret == 0);
2888                 if (check_path_shared(root, path))
2889                         goto out;
2890                 btrfs_release_path(root, path);
2891         }
2892
2893         if (!check_link) {
2894                 err = 0;
2895                 goto out;
2896         }
2897
2898         di = btrfs_lookup_dir_item(trans, root, path, dir->i_ino,
2899                                 dentry->d_name.name, dentry->d_name.len, 0);
2900         if (IS_ERR(di)) {
2901                 err = PTR_ERR(di);
2902                 goto out;
2903         }
2904         if (di) {
2905                 if (check_path_shared(root, path))
2906                         goto out;
2907         } else {
2908                 err = 0;
2909                 goto out;
2910         }
2911         btrfs_release_path(root, path);
2912
2913         ref = btrfs_lookup_inode_ref(trans, root, path,
2914                                 dentry->d_name.name, dentry->d_name.len,
2915                                 inode->i_ino, dir->i_ino, 0);
2916         if (IS_ERR(ref)) {
2917                 err = PTR_ERR(ref);
2918                 goto out;
2919         }
2920         BUG_ON(!ref);
2921         if (check_path_shared(root, path))
2922                 goto out;
2923         index = btrfs_inode_ref_index(path->nodes[0], ref);
2924         btrfs_release_path(root, path);
2925
2926         di = btrfs_lookup_dir_index_item(trans, root, path, dir->i_ino, index,
2927                                 dentry->d_name.name, dentry->d_name.len, 0);
2928         if (IS_ERR(di)) {
2929                 err = PTR_ERR(di);
2930                 goto out;
2931         }
2932         BUG_ON(ret == -ENOENT);
2933         if (check_path_shared(root, path))
2934                 goto out;
2935
2936         err = 0;
2937 out:
2938         btrfs_free_path(path);
2939         if (err) {
2940                 btrfs_end_transaction(trans, root);
2941                 root->fs_info->enospc_unlink = 0;
2942                 return ERR_PTR(err);
2943         }
2944
2945         trans->block_rsv = &root->fs_info->global_block_rsv;
2946         return trans;
2947 }
2948
2949 static void __unlink_end_trans(struct btrfs_trans_handle *trans,
2950                                struct btrfs_root *root)
2951 {
2952         if (trans->block_rsv == &root->fs_info->global_block_rsv) {
2953                 BUG_ON(!root->fs_info->enospc_unlink);
2954                 root->fs_info->enospc_unlink = 0;
2955         }
2956         btrfs_end_transaction_throttle(trans, root);
2957 }
2958
2959 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
2960 {
2961         struct btrfs_root *root = BTRFS_I(dir)->root;
2962         struct btrfs_trans_handle *trans;
2963         struct inode *inode = dentry->d_inode;
2964         int ret;
2965         unsigned long nr = 0;
2966
2967         trans = __unlink_start_trans(dir, dentry);
2968         if (IS_ERR(trans))
2969                 return PTR_ERR(trans);
2970
2971         btrfs_set_trans_block_group(trans, dir);
2972
2973         btrfs_record_unlink_dir(trans, dir, dentry->d_inode, 0);
2974
2975         ret = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
2976                                  dentry->d_name.name, dentry->d_name.len);
2977         BUG_ON(ret);
2978
2979         if (inode->i_nlink == 0) {
2980                 ret = btrfs_orphan_add(trans, inode);
2981                 BUG_ON(ret);
2982         }
2983
2984         nr = trans->blocks_used;
2985         __unlink_end_trans(trans, root);
2986         btrfs_btree_balance_dirty(root, nr);
2987         return ret;
2988 }
2989
2990 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
2991                         struct btrfs_root *root,
2992                         struct inode *dir, u64 objectid,
2993                         const char *name, int name_len)
2994 {
2995         struct btrfs_path *path;
2996         struct extent_buffer *leaf;
2997         struct btrfs_dir_item *di;
2998         struct btrfs_key key;
2999         u64 index;
3000         int ret;
3001
3002         path = btrfs_alloc_path();
3003         if (!path)
3004                 return -ENOMEM;
3005
3006         di = btrfs_lookup_dir_item(trans, root, path, dir->i_ino,
3007                                    name, name_len, -1);
3008         BUG_ON(!di || IS_ERR(di));
3009
3010         leaf = path->nodes[0];
3011         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3012         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
3013         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3014         BUG_ON(ret);
3015         btrfs_release_path(root, path);
3016
3017         ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
3018                                  objectid, root->root_key.objectid,
3019                                  dir->i_ino, &index, name, name_len);
3020         if (ret < 0) {
3021                 BUG_ON(ret != -ENOENT);
3022                 di = btrfs_search_dir_index_item(root, path, dir->i_ino,
3023                                                  name, name_len);
3024                 BUG_ON(!di || IS_ERR(di));
3025
3026                 leaf = path->nodes[0];
3027                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3028                 btrfs_release_path(root, path);
3029                 index = key.offset;
3030         }
3031
3032         di = btrfs_lookup_dir_index_item(trans, root, path, dir->i_ino,
3033                                          index, name, name_len, -1);
3034         BUG_ON(!di || IS_ERR(di));
3035
3036         leaf = path->nodes[0];
3037         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3038         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
3039         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3040         BUG_ON(ret);
3041         btrfs_release_path(root, path);
3042
3043         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
3044         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
3045         ret = btrfs_update_inode(trans, root, dir);
3046         BUG_ON(ret);
3047
3048         btrfs_free_path(path);
3049         return 0;
3050 }
3051
3052 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
3053 {
3054         struct inode *inode = dentry->d_inode;
3055         int err = 0;
3056         struct btrfs_root *root = BTRFS_I(dir)->root;
3057         struct btrfs_trans_handle *trans;
3058         unsigned long nr = 0;
3059
3060         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE ||
3061             inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
3062                 return -ENOTEMPTY;
3063
3064         trans = __unlink_start_trans(dir, dentry);
3065         if (IS_ERR(trans))
3066                 return PTR_ERR(trans);
3067
3068         btrfs_set_trans_block_group(trans, dir);
3069
3070         if (unlikely(inode->i_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
3071                 err = btrfs_unlink_subvol(trans, root, dir,
3072                                           BTRFS_I(inode)->location.objectid,
3073                                           dentry->d_name.name,
3074                                           dentry->d_name.len);
3075                 goto out;
3076         }
3077
3078         err = btrfs_orphan_add(trans, inode);
3079         if (err)
3080                 goto out;
3081
3082         /* now the directory is empty */
3083         err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3084                                  dentry->d_name.name, dentry->d_name.len);
3085         if (!err)
3086                 btrfs_i_size_write(inode, 0);
3087 out:
3088         nr = trans->blocks_used;
3089         __unlink_end_trans(trans, root);
3090         btrfs_btree_balance_dirty(root, nr);
3091
3092         return err;
3093 }
3094
3095 #if 0
3096 /*
3097  * when truncating bytes in a file, it is possible to avoid reading
3098  * the leaves that contain only checksum items.  This can be the
3099  * majority of the IO required to delete a large file, but it must
3100  * be done carefully.
3101  *
3102  * The keys in the level just above the leaves are checked to make sure
3103  * the lowest key in a given leaf is a csum key, and starts at an offset
3104  * after the new  size.
3105  *
3106  * Then the key for the next leaf is checked to make sure it also has
3107  * a checksum item for the same file.  If it does, we know our target leaf
3108  * contains only checksum items, and it can be safely freed without reading
3109  * it.
3110  *
3111  * This is just an optimization targeted at large files.  It may do
3112  * nothing.  It will return 0 unless things went badly.
3113  */
3114 static noinline int drop_csum_leaves(struct btrfs_trans_handle *trans,
3115                                      struct btrfs_root *root,
3116                                      struct btrfs_path *path,
3117                                      struct inode *inode, u64 new_size)
3118 {
3119         struct btrfs_key key;
3120         int ret;
3121         int nritems;
3122         struct btrfs_key found_key;
3123         struct btrfs_key other_key;
3124         struct btrfs_leaf_ref *ref;
3125         u64 leaf_gen;
3126         u64 leaf_start;
3127
3128         path->lowest_level = 1;
3129         key.objectid = inode->i_ino;
3130         key.type = BTRFS_CSUM_ITEM_KEY;
3131         key.offset = new_size;
3132 again:
3133         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3134         if (ret < 0)
3135                 goto out;
3136
3137         if (path->nodes[1] == NULL) {
3138                 ret = 0;
3139                 goto out;
3140         }
3141         ret = 0;
3142         btrfs_node_key_to_cpu(path->nodes[1], &found_key, path->slots[1]);
3143         nritems = btrfs_header_nritems(path->nodes[1]);
3144
3145         if (!nritems)
3146                 goto out;
3147
3148         if (path->slots[1] >= nritems)
3149                 goto next_node;
3150
3151         /* did we find a key greater than anything we want to delete? */
3152         if (found_key.objectid > inode->i_ino ||
3153            (found_key.objectid == inode->i_ino && found_key.type > key.type))
3154                 goto out;
3155
3156         /* we check the next key in the node to make sure the leave contains
3157          * only checksum items.  This comparison doesn't work if our
3158          * leaf is the last one in the node
3159          */
3160         if (path->slots[1] + 1 >= nritems) {
3161 next_node:
3162                 /* search forward from the last key in the node, this
3163                  * will bring us into the next node in the tree
3164                  */
3165                 btrfs_node_key_to_cpu(path->nodes[1], &found_key, nritems - 1);
3166
3167                 /* unlikely, but we inc below, so check to be safe */
3168                 if (found_key.offset == (u64)-1)
3169                         goto out;
3170
3171                 /* search_forward needs a path with locks held, do the
3172                  * search again for the original key.  It is possible
3173                  * this will race with a balance and return a path that
3174                  * we could modify, but this drop is just an optimization
3175                  * and is allowed to miss some leaves.
3176                  */
3177                 btrfs_release_path(root, path);
3178                 found_key.offset++;
3179
3180                 /* setup a max key for search_forward */
3181                 other_key.offset = (u64)-1;
3182                 other_key.type = key.type;
3183                 other_key.objectid = key.objectid;
3184
3185                 path->keep_locks = 1;
3186                 ret = btrfs_search_forward(root, &found_key, &other_key,
3187                                            path, 0, 0);
3188                 path->keep_locks = 0;
3189                 if (ret || found_key.objectid != key.objectid ||
3190                     found_key.type != key.type) {
3191                         ret = 0;
3192                         goto out;
3193                 }
3194
3195                 key.offset = found_key.offset;
3196                 btrfs_release_path(root, path);
3197                 cond_resched();
3198                 goto again;
3199         }
3200
3201         /* we know there's one more slot after us in the tree,
3202          * read that key so we can verify it is also a checksum item
3203          */
3204         btrfs_node_key_to_cpu(path->nodes[1], &other_key, path->slots[1] + 1);
3205
3206         if (found_key.objectid < inode->i_ino)
3207                 goto next_key;
3208
3209         if (found_key.type != key.type || found_key.offset < new_size)
3210                 goto next_key;
3211
3212         /*
3213          * if the key for the next leaf isn't a csum key from this objectid,
3214          * we can't be sure there aren't good items inside this leaf.
3215          * Bail out
3216          */
3217         if (other_key.objectid != inode->i_ino || other_key.type != key.type)
3218                 goto out;
3219
3220         leaf_start = btrfs_node_blockptr(path->nodes[1], path->slots[1]);
3221         leaf_gen = btrfs_node_ptr_generation(path->nodes[1], path->slots[1]);
3222         /*
3223          * it is safe to delete this leaf, it contains only
3224          * csum items from this inode at an offset >= new_size
3225          */
3226         ret = btrfs_del_leaf(trans, root, path, leaf_start);
3227         BUG_ON(ret);
3228
3229         if (root->ref_cows && leaf_gen < trans->transid) {
3230                 ref = btrfs_alloc_leaf_ref(root, 0);
3231                 if (ref) {
3232                         ref->root_gen = root->root_key.offset;
3233                         ref->bytenr = leaf_start;
3234                         ref->owner = 0;
3235                         ref->generation = leaf_gen;
3236                         ref->nritems = 0;
3237
3238                         btrfs_sort_leaf_ref(ref);
3239
3240                         ret = btrfs_add_leaf_ref(root, ref, 0);
3241                         WARN_ON(ret);
3242                         btrfs_free_leaf_ref(root, ref);
3243                 } else {
3244                         WARN_ON(1);
3245                 }
3246         }
3247 next_key:
3248         btrfs_release_path(root, path);
3249
3250         if (other_key.objectid == inode->i_ino &&
3251             other_key.type == key.type && other_key.offset > key.offset) {
3252                 key.offset = other_key.offset;
3253                 cond_resched();
3254                 goto again;
3255         }
3256         ret = 0;
3257 out:
3258         /* fixup any changes we've made to the path */
3259         path->lowest_level = 0;
3260         path->keep_locks = 0;
3261         btrfs_release_path(root, path);
3262         return ret;
3263 }
3264
3265 #endif
3266
3267 /*
3268  * this can truncate away extent items, csum items and directory items.
3269  * It starts at a high offset and removes keys until it can't find
3270  * any higher than new_size
3271  *
3272  * csum items that cross the new i_size are truncated to the new size
3273  * as well.
3274  *
3275  * min_type is the minimum key type to truncate down to.  If set to 0, this
3276  * will kill all the items on this inode, including the INODE_ITEM_KEY.
3277  */
3278 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
3279                                struct btrfs_root *root,
3280                                struct inode *inode,
3281                                u64 new_size, u32 min_type)
3282 {
3283         struct btrfs_path *path;
3284         struct extent_buffer *leaf;
3285         struct btrfs_file_extent_item *fi;
3286         struct btrfs_key key;
3287         struct btrfs_key found_key;
3288         u64 extent_start = 0;
3289         u64 extent_num_bytes = 0;
3290         u64 extent_offset = 0;
3291         u64 item_end = 0;
3292         u64 mask = root->sectorsize - 1;
3293         u32 found_type = (u8)-1;
3294         int found_extent;
3295         int del_item;
3296         int pending_del_nr = 0;
3297         int pending_del_slot = 0;
3298         int extent_type = -1;
3299         int encoding;
3300         int ret;
3301         int err = 0;
3302
3303         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
3304
3305         if (root->ref_cows || root == root->fs_info->tree_root)
3306                 btrfs_drop_extent_cache(inode, new_size & (~mask), (u64)-1, 0);
3307
3308         path = btrfs_alloc_path();
3309         BUG_ON(!path);
3310         path->reada = -1;
3311
3312         key.objectid = inode->i_ino;
3313         key.offset = (u64)-1;
3314         key.type = (u8)-1;
3315
3316 search_again:
3317         path->leave_spinning = 1;
3318         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3319         if (ret < 0) {
3320                 err = ret;
3321                 goto out;
3322         }
3323
3324         if (ret > 0) {
3325                 /* there are no items in the tree for us to truncate, we're
3326                  * done
3327                  */
3328                 if (path->slots[0] == 0)
3329                         goto out;
3330                 path->slots[0]--;
3331         }
3332
3333         while (1) {
3334                 fi = NULL;
3335                 leaf = path->nodes[0];
3336                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3337                 found_type = btrfs_key_type(&found_key);
3338                 encoding = 0;
3339
3340                 if (found_key.objectid != inode->i_ino)
3341                         break;
3342
3343                 if (found_type < min_type)
3344                         break;
3345
3346                 item_end = found_key.offset;
3347                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
3348                         fi = btrfs_item_ptr(leaf, path->slots[0],
3349                                             struct btrfs_file_extent_item);
3350                         extent_type = btrfs_file_extent_type(leaf, fi);
3351                         encoding = btrfs_file_extent_compression(leaf, fi);
3352                         encoding |= btrfs_file_extent_encryption(leaf, fi);
3353                         encoding |= btrfs_file_extent_other_encoding(leaf, fi);
3354
3355                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
3356                                 item_end +=
3357                                     btrfs_file_extent_num_bytes(leaf, fi);
3358                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
3359                                 item_end += btrfs_file_extent_inline_len(leaf,
3360                                                                          fi);
3361                         }
3362                         item_end--;
3363                 }
3364                 if (found_type > min_type) {
3365                         del_item = 1;
3366                 } else {
3367                         if (item_end < new_size)
3368                                 break;
3369                         if (found_key.offset >= new_size)
3370                                 del_item = 1;
3371                         else
3372                                 del_item = 0;
3373                 }
3374                 found_extent = 0;
3375                 /* FIXME, shrink the extent if the ref count is only 1 */
3376                 if (found_type != BTRFS_EXTENT_DATA_KEY)
3377                         goto delete;
3378
3379                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
3380                         u64 num_dec;
3381                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
3382                         if (!del_item && !encoding) {
3383                                 u64 orig_num_bytes =
3384                                         btrfs_file_extent_num_bytes(leaf, fi);
3385                                 extent_num_bytes = new_size -
3386                                         found_key.offset + root->sectorsize - 1;
3387                                 extent_num_bytes = extent_num_bytes &
3388                                         ~((u64)root->sectorsize - 1);
3389                                 btrfs_set_file_extent_num_bytes(leaf, fi,
3390                                                          extent_num_bytes);
3391                                 num_dec = (orig_num_bytes -
3392                                            extent_num_bytes);
3393                                 if (root->ref_cows && extent_start != 0)
3394                                         inode_sub_bytes(inode, num_dec);
3395                                 btrfs_mark_buffer_dirty(leaf);
3396                         } else {
3397                                 extent_num_bytes =
3398                                         btrfs_file_extent_disk_num_bytes(leaf,
3399                                                                          fi);
3400                                 extent_offset = found_key.offset -
3401                                         btrfs_file_extent_offset(leaf, fi);
3402
3403                                 /* FIXME blocksize != 4096 */
3404                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
3405                                 if (extent_start != 0) {
3406                                         found_extent = 1;
3407                                         if (root->ref_cows)
3408                                                 inode_sub_bytes(inode, num_dec);
3409                                 }
3410                         }
3411                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
3412                         /*
3413                          * we can't truncate inline items that have had
3414                          * special encodings
3415                          */
3416                         if (!del_item &&
3417                             btrfs_file_extent_compression(leaf, fi) == 0 &&
3418                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
3419                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
3420                                 u32 size = new_size - found_key.offset;
3421
3422                                 if (root->ref_cows) {
3423                                         inode_sub_bytes(inode, item_end + 1 -
3424                                                         new_size);
3425                                 }
3426                                 size =
3427                                     btrfs_file_extent_calc_inline_size(size);
3428                                 ret = btrfs_truncate_item(trans, root, path,
3429                                                           size, 1);
3430                                 BUG_ON(ret);
3431                         } else if (root->ref_cows) {
3432                                 inode_sub_bytes(inode, item_end + 1 -
3433                                                 found_key.offset);
3434                         }
3435                 }
3436 delete:
3437                 if (del_item) {
3438                         if (!pending_del_nr) {
3439                                 /* no pending yet, add ourselves */
3440                                 pending_del_slot = path->slots[0];
3441                                 pending_del_nr = 1;
3442                         } else if (pending_del_nr &&
3443                                    path->slots[0] + 1 == pending_del_slot) {
3444                                 /* hop on the pending chunk */
3445                                 pending_del_nr++;
3446                                 pending_del_slot = path->slots[0];
3447                         } else {
3448                                 BUG();
3449                         }
3450                 } else {
3451                         break;
3452                 }
3453                 if (found_extent && (root->ref_cows ||
3454                                      root == root->fs_info->tree_root)) {
3455                         btrfs_set_path_blocking(path);
3456                         ret = btrfs_free_extent(trans, root, extent_start,
3457                                                 extent_num_bytes, 0,
3458                                                 btrfs_header_owner(leaf),
3459                                                 inode->i_ino, extent_offset);
3460                         BUG_ON(ret);
3461                 }
3462
3463                 if (found_type == BTRFS_INODE_ITEM_KEY)
3464                         break;
3465
3466                 if (path->slots[0] == 0 ||
3467                     path->slots[0] != pending_del_slot) {
3468                         if (root->ref_cows) {
3469                                 err = -EAGAIN;
3470                                 goto out;
3471                         }
3472                         if (pending_del_nr) {
3473                                 ret = btrfs_del_items(trans, root, path,
3474                                                 pending_del_slot,
3475                                                 pending_del_nr);
3476                                 BUG_ON(ret);
3477                                 pending_del_nr = 0;
3478                         }
3479                         btrfs_release_path(root, path);
3480                         goto search_again;
3481                 } else {
3482                         path->slots[0]--;
3483                 }
3484         }
3485 out:
3486         if (pending_del_nr) {
3487                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
3488                                       pending_del_nr);
3489                 BUG_ON(ret);
3490         }
3491         btrfs_free_path(path);
3492         return err;
3493 }
3494
3495 /*
3496  * taken from block_truncate_page, but does cow as it zeros out
3497  * any bytes left in the last page in the file.
3498  */
3499 static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
3500 {
3501         struct inode *inode = mapping->host;
3502         struct btrfs_root *root = BTRFS_I(inode)->root;
3503         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3504         struct btrfs_ordered_extent *ordered;
3505         struct extent_state *cached_state = NULL;
3506         char *kaddr;
3507         u32 blocksize = root->sectorsize;
3508         pgoff_t index = from >> PAGE_CACHE_SHIFT;
3509         unsigned offset = from & (PAGE_CACHE_SIZE-1);
3510         struct page *page;
3511         int ret = 0;
3512         u64 page_start;
3513         u64 page_end;
3514
3515         if ((offset & (blocksize - 1)) == 0)
3516                 goto out;
3517         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
3518         if (ret)
3519                 goto out;
3520
3521         ret = -ENOMEM;
3522 again:
3523         page = grab_cache_page(mapping, index);
3524         if (!page) {
3525                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
3526                 goto out;
3527         }
3528
3529         page_start = page_offset(page);
3530         page_end = page_start + PAGE_CACHE_SIZE - 1;
3531
3532         if (!PageUptodate(page)) {
3533                 ret = btrfs_readpage(NULL, page);
3534                 lock_page(page);
3535                 if (page->mapping != mapping) {
3536                         unlock_page(page);
3537                         page_cache_release(page);
3538                         goto again;
3539                 }
3540                 if (!PageUptodate(page)) {
3541                         ret = -EIO;
3542                         goto out_unlock;
3543                 }
3544         }
3545         wait_on_page_writeback(page);
3546
3547         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state,
3548                          GFP_NOFS);
3549         set_page_extent_mapped(page);
3550
3551         ordered = btrfs_lookup_ordered_extent(inode, page_start);
3552         if (ordered) {
3553                 unlock_extent_cached(io_tree, page_start, page_end,
3554                                      &cached_state, GFP_NOFS);
3555                 unlock_page(page);
3556                 page_cache_release(page);
3557                 btrfs_start_ordered_extent(inode, ordered, 1);
3558                 btrfs_put_ordered_extent(ordered);
3559                 goto again;
3560         }
3561
3562         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
3563                           EXTENT_DIRTY | EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING,
3564                           0, 0, &cached_state, GFP_NOFS);
3565
3566         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
3567                                         &cached_state);
3568         if (ret) {
3569                 unlock_extent_cached(io_tree, page_start, page_end,
3570                                      &cached_state, GFP_NOFS);
3571                 goto out_unlock;
3572         }
3573
3574         ret = 0;
3575         if (offset != PAGE_CACHE_SIZE) {
3576                 kaddr = kmap(page);
3577                 memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset);
3578                 flush_dcache_page(page);
3579                 kunmap(page);
3580         }
3581         ClearPageChecked(page);
3582         set_page_dirty(page);
3583         unlock_extent_cached(io_tree, page_start, page_end, &cached_state,
3584                              GFP_NOFS);
3585
3586 out_unlock:
3587         if (ret)
3588                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
3589         unlock_page(page);
3590         page_cache_release(page);
3591 out:
3592         return ret;
3593 }
3594
3595 /*
3596  * This function puts in dummy file extents for the area we're creating a hole
3597  * for.  So if we are truncating this file to a larger size we need to insert
3598  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
3599  * the range between oldsize and size
3600  */
3601 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
3602 {
3603         struct btrfs_trans_handle *trans;
3604         struct btrfs_root *root = BTRFS_I(inode)->root;
3605         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3606         struct extent_map *em = NULL;
3607         struct extent_state *cached_state = NULL;
3608         u64 mask = root->sectorsize - 1;
3609         u64 hole_start = (oldsize + mask) & ~mask;
3610         u64 block_end = (size + mask) & ~mask;
3611         u64 last_byte;
3612         u64 cur_offset;
3613         u64 hole_size;
3614         int err = 0;
3615
3616         if (size <= hole_start)
3617                 return 0;
3618
3619         while (1) {
3620                 struct btrfs_ordered_extent *ordered;
3621                 btrfs_wait_ordered_range(inode, hole_start,
3622                                          block_end - hole_start);
3623                 lock_extent_bits(io_tree, hole_start, block_end - 1, 0,
3624                                  &cached_state, GFP_NOFS);
3625                 ordered = btrfs_lookup_ordered_extent(inode, hole_start);
3626                 if (!ordered)
3627                         break;
3628                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
3629                                      &cached_state, GFP_NOFS);
3630                 btrfs_put_ordered_extent(ordered);
3631         }
3632
3633         cur_offset = hole_start;
3634         while (1) {
3635                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
3636                                 block_end - cur_offset, 0);
3637                 BUG_ON(IS_ERR(em) || !em);
3638                 last_byte = min(extent_map_end(em), block_end);
3639                 last_byte = (last_byte + mask) & ~mask;
3640                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
3641                         u64 hint_byte = 0;
3642                         hole_size = last_byte - cur_offset;
3643
3644                         trans = btrfs_start_transaction(root, 2);
3645                         if (IS_ERR(trans)) {
3646                                 err = PTR_ERR(trans);
3647                                 break;
3648                         }
3649                         btrfs_set_trans_block_group(trans, inode);
3650
3651                         err = btrfs_drop_extents(trans, inode, cur_offset,
3652                                                  cur_offset + hole_size,
3653                                                  &hint_byte, 1);
3654                         if (err)
3655                                 break;
3656
3657                         err = btrfs_insert_file_extent(trans, root,
3658                                         inode->i_ino, cur_offset, 0,
3659                                         0, hole_size, 0, hole_size,
3660                                         0, 0, 0);
3661                         if (err)
3662                                 break;
3663
3664                         btrfs_drop_extent_cache(inode, hole_start,
3665                                         last_byte - 1, 0);
3666
3667                         btrfs_end_transaction(trans, root);
3668                 }
3669                 free_extent_map(em);
3670                 em = NULL;
3671                 cur_offset = last_byte;
3672                 if (cur_offset >= block_end)
3673                         break;
3674         }
3675
3676         free_extent_map(em);
3677         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state,
3678                              GFP_NOFS);
3679         return err;
3680 }
3681
3682 static int btrfs_setsize(struct inode *inode, loff_t newsize)
3683 {
3684         loff_t oldsize = i_size_read(inode);
3685         int ret;
3686
3687         if (newsize == oldsize)
3688                 return 0;
3689
3690         if (newsize > oldsize) {
3691                 i_size_write(inode, newsize);
3692                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
3693                 truncate_pagecache(inode, oldsize, newsize);
3694                 ret = btrfs_cont_expand(inode, oldsize, newsize);
3695                 if (ret) {
3696                         btrfs_setsize(inode, oldsize);
3697                         return ret;
3698                 }
3699
3700                 mark_inode_dirty(inode);
3701         } else {
3702
3703                 /*
3704                  * We're truncating a file that used to have good data down to
3705                  * zero. Make sure it gets into the ordered flush list so that
3706                  * any new writes get down to disk quickly.
3707                  */
3708                 if (newsize == 0)
3709                         BTRFS_I(inode)->ordered_data_close = 1;
3710
3711                 /* we don't support swapfiles, so vmtruncate shouldn't fail */
3712                 truncate_setsize(inode, newsize);
3713                 ret = btrfs_truncate(inode);
3714         }
3715
3716         return ret;
3717 }
3718
3719 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
3720 {
3721         struct inode *inode = dentry->d_inode;
3722         struct btrfs_root *root = BTRFS_I(inode)->root;
3723         int err;
3724
3725         if (btrfs_root_readonly(root))
3726                 return -EROFS;
3727
3728         err = inode_change_ok(inode, attr);
3729         if (err)
3730                 return err;
3731
3732         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
3733                 err = btrfs_setsize(inode, attr->ia_size);
3734                 if (err)
3735                         return err;
3736         }
3737
3738         if (attr->ia_valid) {
3739                 setattr_copy(inode, attr);
3740                 mark_inode_dirty(inode);
3741
3742                 if (attr->ia_valid & ATTR_MODE)
3743                         err = btrfs_acl_chmod(inode);
3744         }
3745
3746         return err;
3747 }
3748
3749 void btrfs_evict_inode(struct inode *inode)
3750 {
3751         struct btrfs_trans_handle *trans;
3752         struct btrfs_root *root = BTRFS_I(inode)->root;
3753         unsigned long nr;
3754         int ret;
3755
3756         trace_btrfs_inode_evict(inode);
3757
3758         truncate_inode_pages(&inode->i_data, 0);
3759         if (inode->i_nlink && (btrfs_root_refs(&root->root_item) != 0 ||
3760                                root == root->fs_info->tree_root))
3761                 goto no_delete;
3762
3763         if (is_bad_inode(inode)) {
3764                 btrfs_orphan_del(NULL, inode);
3765                 goto no_delete;
3766         }
3767         /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
3768         btrfs_wait_ordered_range(inode, 0, (u64)-1);
3769
3770         if (root->fs_info->log_root_recovering) {
3771                 BUG_ON(!list_empty(&BTRFS_I(inode)->i_orphan));
3772                 goto no_delete;
3773         }
3774
3775         if (inode->i_nlink > 0) {
3776                 BUG_ON(btrfs_root_refs(&root->root_item) != 0);
3777                 goto no_delete;
3778         }
3779
3780         btrfs_i_size_write(inode, 0);
3781
3782         while (1) {
3783                 trans = btrfs_start_transaction(root, 0);
3784                 BUG_ON(IS_ERR(trans));
3785                 btrfs_set_trans_block_group(trans, inode);
3786                 trans->block_rsv = root->orphan_block_rsv;
3787
3788                 ret = btrfs_block_rsv_check(trans, root,
3789                                             root->orphan_block_rsv, 0, 5);
3790                 if (ret) {
3791                         BUG_ON(ret != -EAGAIN);
3792                         ret = btrfs_commit_transaction(trans, root);
3793                         BUG_ON(ret);
3794                         continue;
3795                 }
3796
3797                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
3798                 if (ret != -EAGAIN)
3799                         break;
3800
3801                 nr = trans->blocks_used;
3802                 btrfs_end_transaction(trans, root);
3803                 trans = NULL;
3804                 btrfs_btree_balance_dirty(root, nr);
3805
3806         }
3807
3808         if (ret == 0) {
3809                 ret = btrfs_orphan_del(trans, inode);
3810                 BUG_ON(ret);
3811         }
3812
3813         nr = trans->blocks_used;
3814         btrfs_end_transaction(trans, root);
3815         btrfs_btree_balance_dirty(root, nr);
3816 no_delete:
3817         end_writeback(inode);
3818         return;
3819 }
3820
3821 /*
3822  * this returns the key found in the dir entry in the location pointer.
3823  * If no dir entries were found, location->objectid is 0.
3824  */
3825 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
3826                                struct btrfs_key *location)
3827 {
3828         const char *name = dentry->d_name.name;
3829         int namelen = dentry->d_name.len;
3830         struct btrfs_dir_item *di;
3831         struct btrfs_path *path;
3832         struct btrfs_root *root = BTRFS_I(dir)->root;
3833         int ret = 0;
3834
3835         path = btrfs_alloc_path();
3836         BUG_ON(!path);
3837
3838         di = btrfs_lookup_dir_item(NULL, root, path, dir->i_ino, name,
3839                                     namelen, 0);
3840         if (IS_ERR(di))
3841                 ret = PTR_ERR(di);
3842
3843         if (!di || IS_ERR(di))
3844                 goto out_err;
3845
3846         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
3847 out:
3848         btrfs_free_path(path);
3849         return ret;
3850 out_err:
3851         location->objectid = 0;
3852         goto out;
3853 }
3854
3855 /*
3856  * when we hit a tree root in a directory, the btrfs part of the inode
3857  * needs to be changed to reflect the root directory of the tree root.  This
3858  * is kind of like crossing a mount point.
3859  */
3860 static int fixup_tree_root_location(struct btrfs_root *root,
3861                                     struct inode *dir,
3862                                     struct dentry *dentry,
3863                                     struct btrfs_key *location,
3864                                     struct btrfs_root **sub_root)
3865 {
3866         struct btrfs_path *path;
3867         struct btrfs_root *new_root;
3868         struct btrfs_root_ref *ref;
3869         struct extent_buffer *leaf;
3870         int ret;
3871         int err = 0;
3872
3873         path = btrfs_alloc_path();
3874         if (!path) {
3875                 err = -ENOMEM;
3876                 goto out;
3877         }
3878
3879         err = -ENOENT;
3880         ret = btrfs_find_root_ref(root->fs_info->tree_root, path,
3881                                   BTRFS_I(dir)->root->root_key.objectid,
3882                                   location->objectid);
3883         if (ret) {
3884                 if (ret < 0)
3885                         err = ret;
3886                 goto out;
3887         }
3888
3889         leaf = path->nodes[0];
3890         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
3891         if (btrfs_root_ref_dirid(leaf, ref) != dir->i_ino ||
3892             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
3893                 goto out;
3894
3895         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
3896                                    (unsigned long)(ref + 1),
3897                                    dentry->d_name.len);
3898         if (ret)
3899                 goto out;
3900
3901         btrfs_release_path(root->fs_info->tree_root, path);
3902
3903         new_root = btrfs_read_fs_root_no_name(root->fs_info, location);
3904         if (IS_ERR(new_root)) {
3905                 err = PTR_ERR(new_root);
3906                 goto out;
3907         }
3908
3909         if (btrfs_root_refs(&new_root->root_item) == 0) {
3910                 err = -ENOENT;
3911                 goto out;
3912         }
3913
3914         *sub_root = new_root;
3915         location->objectid = btrfs_root_dirid(&new_root->root_item);
3916         location->type = BTRFS_INODE_ITEM_KEY;
3917         location->offset = 0;
3918         err = 0;
3919 out:
3920         btrfs_free_path(path);
3921         return err;
3922 }
3923
3924 static void inode_tree_add(struct inode *inode)
3925 {
3926         struct btrfs_root *root = BTRFS_I(inode)->root;
3927         struct btrfs_inode *entry;
3928         struct rb_node **p;
3929         struct rb_node *parent;
3930 again:
3931         p = &root->inode_tree.rb_node;
3932         parent = NULL;
3933
3934         if (inode_unhashed(inode))
3935                 return;
3936
3937         spin_lock(&root->inode_lock);
3938         while (*p) {
3939                 parent = *p;
3940                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
3941
3942                 if (inode->i_ino < entry->vfs_inode.i_ino)
3943                         p = &parent->rb_left;
3944                 else if (inode->i_ino > entry->vfs_inode.i_ino)
3945                         p = &parent->rb_right;
3946                 else {
3947                         WARN_ON(!(entry->vfs_inode.i_state &
3948                                   (I_WILL_FREE | I_FREEING)));
3949                         rb_erase(parent, &root->inode_tree);
3950                         RB_CLEAR_NODE(parent);
3951                         spin_unlock(&root->inode_lock);
3952                         goto again;
3953                 }
3954         }
3955         rb_link_node(&BTRFS_I(inode)->rb_node, parent, p);
3956         rb_insert_color(&BTRFS_I(inode)->rb_node, &root->inode_tree);
3957         spin_unlock(&root->inode_lock);
3958 }
3959
3960 static void inode_tree_del(struct inode *inode)
3961 {
3962         struct btrfs_root *root = BTRFS_I(inode)->root;
3963         int empty = 0;
3964
3965         spin_lock(&root->inode_lock);
3966         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
3967                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
3968                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
3969                 empty = RB_EMPTY_ROOT(&root->inode_tree);
3970         }
3971         spin_unlock(&root->inode_lock);
3972
3973         /*
3974          * Free space cache has inodes in the tree root, but the tree root has a
3975          * root_refs of 0, so this could end up dropping the tree root as a
3976          * snapshot, so we need the extra !root->fs_info->tree_root check to
3977          * make sure we don't drop it.
3978          */
3979         if (empty && btrfs_root_refs(&root->root_item) == 0 &&
3980             root != root->fs_info->tree_root) {
3981                 synchronize_srcu(&root->fs_info->subvol_srcu);
3982                 spin_lock(&root->inode_lock);
3983                 empty = RB_EMPTY_ROOT(&root->inode_tree);
3984                 spin_unlock(&root->inode_lock);
3985                 if (empty)
3986                         btrfs_add_dead_root(root);
3987         }
3988 }
3989
3990 int btrfs_invalidate_inodes(struct btrfs_root *root)
3991 {
3992         struct rb_node *node;
3993         struct rb_node *prev;
3994         struct btrfs_inode *entry;
3995         struct inode *inode;
3996         u64 objectid = 0;
3997
3998         WARN_ON(btrfs_root_refs(&root->root_item) != 0);
3999
4000         spin_lock(&root->inode_lock);
4001 again:
4002         node = root->inode_tree.rb_node;
4003         prev = NULL;
4004         while (node) {
4005                 prev = node;
4006                 entry = rb_entry(node, struct btrfs_inode, rb_node);
4007
4008                 if (objectid < entry->vfs_inode.i_ino)
4009                         node = node->rb_left;
4010                 else if (objectid > entry->vfs_inode.i_ino)
4011                         node = node->rb_right;
4012                 else
4013                         break;
4014         }
4015         if (!node) {
4016                 while (prev) {
4017                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
4018                         if (objectid <= entry->vfs_inode.i_ino) {
4019                                 node = prev;
4020                                 break;
4021                         }
4022                         prev = rb_next(prev);
4023                 }
4024         }
4025         while (node) {
4026                 entry = rb_entry(node, struct btrfs_inode, rb_node);
4027                 objectid = entry->vfs_inode.i_ino + 1;
4028                 inode = igrab(&entry->vfs_inode);
4029                 if (inode) {
4030                         spin_unlock(&root->inode_lock);
4031                         if (atomic_read(&inode->i_count) > 1)
4032                                 d_prune_aliases(inode);
4033                         /*
4034                          * btrfs_drop_inode will have it removed from
4035                          * the inode cache when its usage count
4036                          * hits zero.
4037                          */
4038                         iput(inode);
4039                         cond_resched();
4040                         spin_lock(&root->inode_lock);
4041                         goto again;
4042                 }
4043
4044                 if (cond_resched_lock(&root->inode_lock))
4045                         goto again;
4046
4047                 node = rb_next(node);
4048         }
4049         spin_unlock(&root->inode_lock);
4050         return 0;
4051 }
4052
4053 static int btrfs_init_locked_inode(struct inode *inode, void *p)
4054 {
4055         struct btrfs_iget_args *args = p;
4056         inode->i_ino = args->ino;
4057         BTRFS_I(inode)->root = args->root;
4058         btrfs_set_inode_space_info(args->root, inode);
4059         return 0;
4060 }
4061
4062 static int btrfs_find_actor(struct inode *inode, void *opaque)
4063 {
4064         struct btrfs_iget_args *args = opaque;
4065         return args->ino == inode->i_ino &&
4066                 args->root == BTRFS_I(inode)->root;
4067 }
4068
4069 static struct inode *btrfs_iget_locked(struct super_block *s,
4070                                        u64 objectid,
4071                                        struct btrfs_root *root)
4072 {
4073         struct inode *inode;
4074         struct btrfs_iget_args args;
4075         args.ino = objectid;
4076         args.root = root;
4077
4078         inode = iget5_locked(s, objectid, btrfs_find_actor,
4079                              btrfs_init_locked_inode,
4080                              (void *)&args);
4081         return inode;
4082 }
4083
4084 /* Get an inode object given its location and corresponding root.
4085  * Returns in *is_new if the inode was read from disk
4086  */
4087 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
4088                          struct btrfs_root *root, int *new)
4089 {
4090         struct inode *inode;
4091
4092         inode = btrfs_iget_locked(s, location->objectid, root);
4093         if (!inode)
4094                 return ERR_PTR(-ENOMEM);
4095
4096         if (inode->i_state & I_NEW) {
4097                 BTRFS_I(inode)->root = root;
4098                 memcpy(&BTRFS_I(inode)->location, location, sizeof(*location));
4099                 btrfs_read_locked_inode(inode);
4100                 inode_tree_add(inode);
4101                 unlock_new_inode(inode);
4102                 if (new)
4103                         *new = 1;
4104         }
4105
4106         return inode;
4107 }
4108
4109 static struct inode *new_simple_dir(struct super_block *s,
4110                                     struct btrfs_key *key,
4111                                     struct btrfs_root *root)
4112 {
4113         struct inode *inode = new_inode(s);
4114
4115         if (!inode)
4116                 return ERR_PTR(-ENOMEM);
4117
4118         BTRFS_I(inode)->root = root;
4119         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
4120         BTRFS_I(inode)->dummy_inode = 1;
4121
4122         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
4123         inode->i_op = &simple_dir_inode_operations;
4124         inode->i_fop = &simple_dir_operations;
4125         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
4126         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
4127
4128         return inode;
4129 }
4130
4131 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
4132 {
4133         struct inode *inode;
4134         struct btrfs_root *root = BTRFS_I(dir)->root;
4135         struct btrfs_root *sub_root = root;
4136         struct btrfs_key location;
4137         int index;
4138         int ret;
4139
4140         if (dentry->d_name.len > BTRFS_NAME_LEN)
4141                 return ERR_PTR(-ENAMETOOLONG);
4142
4143         ret = btrfs_inode_by_name(dir, dentry, &location);
4144
4145         if (ret < 0)
4146                 return ERR_PTR(ret);
4147
4148         if (location.objectid == 0)
4149                 return NULL;
4150
4151         if (location.type == BTRFS_INODE_ITEM_KEY) {
4152                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
4153                 return inode;
4154         }
4155
4156         BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
4157
4158         index = srcu_read_lock(&root->fs_info->subvol_srcu);
4159         ret = fixup_tree_root_location(root, dir, dentry,
4160                                        &location, &sub_root);
4161         if (ret < 0) {
4162                 if (ret != -ENOENT)
4163                         inode = ERR_PTR(ret);
4164                 else
4165                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
4166         } else {
4167                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
4168         }
4169         srcu_read_unlock(&root->fs_info->subvol_srcu, index);
4170
4171         if (!IS_ERR(inode) && root != sub_root) {
4172                 down_read(&root->fs_info->cleanup_work_sem);
4173                 if (!(inode->i_sb->s_flags & MS_RDONLY))
4174                         ret = btrfs_orphan_cleanup(sub_root);
4175                 up_read(&root->fs_info->cleanup_work_sem);
4176                 if (ret)
4177                         inode = ERR_PTR(ret);
4178         }
4179
4180         return inode;
4181 }
4182
4183 static int btrfs_dentry_delete(const struct dentry *dentry)
4184 {
4185         struct btrfs_root *root;
4186
4187         if (!dentry->d_inode && !IS_ROOT(dentry))
4188                 dentry = dentry->d_parent;
4189
4190         if (dentry->d_inode) {
4191                 root = BTRFS_I(dentry->d_inode)->root;
4192                 if (btrfs_root_refs(&root->root_item) == 0)
4193                         return 1;
4194         }
4195         return 0;
4196 }
4197
4198 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
4199                                    struct nameidata *nd)
4200 {
4201         struct inode *inode;
4202
4203         inode = btrfs_lookup_dentry(dir, dentry);
4204         if (IS_ERR(inode))
4205                 return ERR_CAST(inode);
4206
4207         return d_splice_alias(inode, dentry);
4208 }
4209
4210 static unsigned char btrfs_filetype_table[] = {
4211         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
4212 };
4213
4214 static int btrfs_real_readdir(struct file *filp, void *dirent,
4215                               filldir_t filldir)
4216 {
4217         struct inode *inode = filp->f_dentry->d_inode;
4218         struct btrfs_root *root = BTRFS_I(inode)->root;
4219         struct btrfs_item *item;
4220         struct btrfs_dir_item *di;
4221         struct btrfs_key key;
4222         struct btrfs_key found_key;
4223         struct btrfs_path *path;
4224         int ret;
4225         struct extent_buffer *leaf;
4226         int slot;
4227         unsigned char d_type;
4228         int over = 0;
4229         u32 di_cur;
4230         u32 di_total;
4231         u32 di_len;
4232         int key_type = BTRFS_DIR_INDEX_KEY;
4233         char tmp_name[32];
4234         char *name_ptr;
4235         int name_len;
4236
4237         /* FIXME, use a real flag for deciding about the key type */
4238         if (root->fs_info->tree_root == root)
4239                 key_type = BTRFS_DIR_ITEM_KEY;
4240
4241         /* special case for "." */
4242         if (filp->f_pos == 0) {
4243                 over = filldir(dirent, ".", 1,
4244                                1, inode->i_ino,
4245                                DT_DIR);
4246                 if (over)
4247                         return 0;
4248                 filp->f_pos = 1;
4249         }
4250         /* special case for .., just use the back ref */
4251         if (filp->f_pos == 1) {
4252                 u64 pino = parent_ino(filp->f_path.dentry);
4253                 over = filldir(dirent, "..", 2,
4254                                2, pino, DT_DIR);
4255                 if (over)
4256                         return 0;
4257                 filp->f_pos = 2;
4258         }
4259         path = btrfs_alloc_path();
4260         path->reada = 2;
4261
4262         btrfs_set_key_type(&key, key_type);
4263         key.offset = filp->f_pos;
4264         key.objectid = inode->i_ino;
4265
4266         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4267         if (ret < 0)
4268                 goto err;
4269
4270         while (1) {
4271                 leaf = path->nodes[0];
4272                 slot = path->slots[0];
4273                 if (slot >= btrfs_header_nritems(leaf)) {
4274                         ret = btrfs_next_leaf(root, path);
4275                         if (ret < 0)
4276                                 goto err;
4277                         else if (ret > 0)
4278                                 break;
4279                         continue;
4280                 }
4281
4282                 item = btrfs_item_nr(leaf, slot);
4283                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
4284
4285                 if (found_key.objectid != key.objectid)
4286                         break;
4287                 if (btrfs_key_type(&found_key) != key_type)
4288                         break;
4289                 if (found_key.offset < filp->f_pos)
4290                         goto next;
4291
4292                 filp->f_pos = found_key.offset;
4293
4294                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
4295                 di_cur = 0;
4296                 di_total = btrfs_item_size(leaf, item);
4297
4298                 while (di_cur < di_total) {
4299                         struct btrfs_key location;
4300
4301                         if (verify_dir_item(root, leaf, di))
4302                                 break;
4303
4304                         name_len = btrfs_dir_name_len(leaf, di);
4305                         if (name_len <= sizeof(tmp_name)) {
4306                                 name_ptr = tmp_name;
4307                         } else {
4308                                 name_ptr = kmalloc(name_len, GFP_NOFS);
4309                                 if (!name_ptr) {
4310                                         ret = -ENOMEM;
4311                                         goto err;
4312                                 }
4313                         }
4314                         read_extent_buffer(leaf, name_ptr,
4315                                            (unsigned long)(di + 1), name_len);
4316
4317                         d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
4318                         btrfs_dir_item_key_to_cpu(leaf, di, &location);
4319
4320                         /* is this a reference to our own snapshot? If so
4321                          * skip it
4322                          */
4323                         if (location.type == BTRFS_ROOT_ITEM_KEY &&
4324                             location.objectid == root->root_key.objectid) {
4325                                 over = 0;
4326                                 goto skip;
4327                         }
4328                         over = filldir(dirent, name_ptr, name_len,
4329                                        found_key.offset, location.objectid,
4330                                        d_type);
4331
4332 skip:
4333                         if (name_ptr != tmp_name)
4334                                 kfree(name_ptr);
4335
4336                         if (over)
4337                                 goto nopos;
4338                         di_len = btrfs_dir_name_len(leaf, di) +
4339                                  btrfs_dir_data_len(leaf, di) + sizeof(*di);
4340                         di_cur += di_len;
4341                         di = (struct btrfs_dir_item *)((char *)di + di_len);
4342                 }
4343 next:
4344                 path->slots[0]++;
4345         }
4346
4347         /* Reached end of directory/root. Bump pos past the last item. */
4348         if (key_type == BTRFS_DIR_INDEX_KEY)
4349                 /*
4350                  * 32-bit glibc will use getdents64, but then strtol -
4351                  * so the last number we can serve is this.
4352                  */
4353                 filp->f_pos = 0x7fffffff;
4354         else
4355                 filp->f_pos++;
4356 nopos:
4357         ret = 0;
4358 err:
4359         btrfs_free_path(path);
4360         return ret;
4361 }
4362
4363 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
4364 {
4365         struct btrfs_root *root = BTRFS_I(inode)->root;
4366         struct btrfs_trans_handle *trans;
4367         int ret = 0;
4368         bool nolock = false;
4369
4370         if (BTRFS_I(inode)->dummy_inode)
4371                 return 0;
4372
4373         smp_mb();
4374         nolock = (root->fs_info->closing && root == root->fs_info->tree_root);
4375
4376         if (wbc->sync_mode == WB_SYNC_ALL) {
4377                 if (nolock)
4378                         trans = btrfs_join_transaction_nolock(root, 1);
4379                 else
4380                         trans = btrfs_join_transaction(root, 1);
4381                 if (IS_ERR(trans))
4382                         return PTR_ERR(trans);
4383                 btrfs_set_trans_block_group(trans, inode);
4384                 if (nolock)
4385                         ret = btrfs_end_transaction_nolock(trans, root);
4386                 else
4387                         ret = btrfs_commit_transaction(trans, root);
4388         }
4389         return ret;
4390 }
4391
4392 /*
4393  * This is somewhat expensive, updating the tree every time the
4394  * inode changes.  But, it is most likely to find the inode in cache.
4395  * FIXME, needs more benchmarking...there are no reasons other than performance
4396  * to keep or drop this code.
4397  */
4398 void btrfs_dirty_inode(struct inode *inode)
4399 {
4400         struct btrfs_root *root = BTRFS_I(inode)->root;
4401         struct btrfs_trans_handle *trans;
4402         int ret;
4403
4404         if (BTRFS_I(inode)->dummy_inode)
4405                 return;
4406
4407         trans = btrfs_join_transaction(root, 1);
4408         BUG_ON(IS_ERR(trans));
4409         btrfs_set_trans_block_group(trans, inode);
4410
4411         ret = btrfs_update_inode(trans, root, inode);
4412         if (ret && ret == -ENOSPC) {
4413                 /* whoops, lets try again with the full transaction */
4414                 btrfs_end_transaction(trans, root);
4415                 trans = btrfs_start_transaction(root, 1);
4416                 if (IS_ERR(trans)) {
4417                         if (printk_ratelimit()) {
4418                                 printk(KERN_ERR "btrfs: fail to "
4419                                        "dirty  inode %lu error %ld\n",
4420                                        inode->i_ino, PTR_ERR(trans));
4421                         }
4422                         return;
4423                 }
4424                 btrfs_set_trans_block_group(trans, inode);
4425
4426                 ret = btrfs_update_inode(trans, root, inode);
4427                 if (ret) {
4428                         if (printk_ratelimit()) {
4429                                 printk(KERN_ERR "btrfs: fail to "
4430                                        "dirty  inode %lu error %d\n",
4431                                        inode->i_ino, ret);
4432                         }
4433                 }
4434         }
4435         btrfs_end_transaction(trans, root);
4436 }
4437
4438 /*
4439  * find the highest existing sequence number in a directory
4440  * and then set the in-memory index_cnt variable to reflect
4441  * free sequence numbers
4442  */
4443 static int btrfs_set_inode_index_count(struct inode *inode)
4444 {
4445         struct btrfs_root *root = BTRFS_I(inode)->root;
4446         struct btrfs_key key, found_key;
4447         struct btrfs_path *path;
4448         struct extent_buffer *leaf;
4449         int ret;
4450
4451         key.objectid = inode->i_ino;
4452         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
4453         key.offset = (u64)-1;
4454
4455         path = btrfs_alloc_path();
4456         if (!path)
4457                 return -ENOMEM;
4458
4459         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4460         if (ret < 0)
4461                 goto out;
4462         /* FIXME: we should be able to handle this */
4463         if (ret == 0)
4464                 goto out;
4465         ret = 0;
4466
4467         /*
4468          * MAGIC NUMBER EXPLANATION:
4469          * since we search a directory based on f_pos we have to start at 2
4470          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
4471          * else has to start at 2
4472          */
4473         if (path->slots[0] == 0) {
4474                 BTRFS_I(inode)->index_cnt = 2;
4475                 goto out;
4476         }
4477
4478         path->slots[0]--;
4479
4480         leaf = path->nodes[0];
4481         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4482
4483         if (found_key.objectid != inode->i_ino ||
4484             btrfs_key_type(&found_key) != BTRFS_DIR_INDEX_KEY) {
4485                 BTRFS_I(inode)->index_cnt = 2;
4486                 goto out;
4487         }
4488
4489         BTRFS_I(inode)->index_cnt = found_key.offset + 1;
4490 out:
4491         btrfs_free_path(path);
4492         return ret;
4493 }
4494
4495 /*
4496  * helper to find a free sequence number in a given directory.  This current
4497  * code is very simple, later versions will do smarter things in the btree
4498  */
4499 int btrfs_set_inode_index(struct inode *dir, u64 *index)
4500 {
4501         int ret = 0;
4502
4503         if (BTRFS_I(dir)->index_cnt == (u64)-1) {
4504                 ret = btrfs_set_inode_index_count(dir);
4505                 if (ret)
4506                         return ret;
4507         }
4508
4509         *index = BTRFS_I(dir)->index_cnt;
4510         BTRFS_I(dir)->index_cnt++;
4511
4512         return ret;
4513 }
4514
4515 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
4516                                      struct btrfs_root *root,
4517                                      struct inode *dir,
4518                                      const char *name, int name_len,
4519                                      u64 ref_objectid, u64 objectid,
4520                                      u64 alloc_hint, int mode, u64 *index)
4521 {
4522         struct inode *inode;
4523         struct btrfs_inode_item *inode_item;
4524         struct btrfs_key *location;
4525         struct btrfs_path *path;
4526         struct btrfs_inode_ref *ref;
4527         struct btrfs_key key[2];
4528         u32 sizes[2];
4529         unsigned long ptr;
4530         int ret;
4531         int owner;
4532
4533         path = btrfs_alloc_path();
4534         BUG_ON(!path);
4535
4536         inode = new_inode(root->fs_info->sb);
4537         if (!inode) {
4538                 btrfs_free_path(path);
4539                 return ERR_PTR(-ENOMEM);
4540         }
4541
4542         if (dir) {
4543                 trace_btrfs_inode_request(dir);
4544
4545                 ret = btrfs_set_inode_index(dir, index);
4546                 if (ret) {
4547                         btrfs_free_path(path);
4548                         iput(inode);
4549                         return ERR_PTR(ret);
4550                 }
4551         }
4552         /*
4553          * index_cnt is ignored for everything but a dir,
4554          * btrfs_get_inode_index_count has an explanation for the magic
4555          * number
4556          */
4557         BTRFS_I(inode)->index_cnt = 2;
4558         BTRFS_I(inode)->root = root;
4559         BTRFS_I(inode)->generation = trans->transid;
4560         inode->i_generation = BTRFS_I(inode)->generation;
4561         btrfs_set_inode_space_info(root, inode);
4562
4563         if (mode & S_IFDIR)
4564                 owner = 0;
4565         else
4566                 owner = 1;
4567         BTRFS_I(inode)->block_group =
4568                         btrfs_find_block_group(root, 0, alloc_hint, owner);
4569
4570         key[0].objectid = objectid;
4571         btrfs_set_key_type(&key[0], BTRFS_INODE_ITEM_KEY);
4572         key[0].offset = 0;
4573
4574         key[1].objectid = objectid;
4575         btrfs_set_key_type(&key[1], BTRFS_INODE_REF_KEY);
4576         key[1].offset = ref_objectid;
4577
4578         sizes[0] = sizeof(struct btrfs_inode_item);
4579         sizes[1] = name_len + sizeof(*ref);
4580
4581         path->leave_spinning = 1;
4582         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, 2);
4583         if (ret != 0)
4584                 goto fail;
4585
4586         inode_init_owner(inode, dir, mode);
4587         inode->i_ino = objectid;
4588         inode_set_bytes(inode, 0);
4589         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
4590         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
4591                                   struct btrfs_inode_item);
4592         fill_inode_item(trans, path->nodes[0], inode_item, inode);
4593
4594         ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
4595                              struct btrfs_inode_ref);
4596         btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
4597         btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
4598         ptr = (unsigned long)(ref + 1);
4599         write_extent_buffer(path->nodes[0], name, ptr, name_len);
4600
4601         btrfs_mark_buffer_dirty(path->nodes[0]);
4602         btrfs_free_path(path);
4603
4604         location = &BTRFS_I(inode)->location;
4605         location->objectid = objectid;
4606         location->offset = 0;
4607         btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
4608
4609         btrfs_inherit_iflags(inode, dir);
4610
4611         if ((mode & S_IFREG)) {
4612                 if (btrfs_test_opt(root, NODATASUM))
4613                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
4614                 if (btrfs_test_opt(root, NODATACOW) ||
4615                     (BTRFS_I(dir)->flags & BTRFS_INODE_NODATACOW))
4616                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW;
4617         }
4618
4619         insert_inode_hash(inode);
4620         inode_tree_add(inode);
4621
4622         trace_btrfs_inode_new(inode);
4623
4624         return inode;
4625 fail:
4626         if (dir)
4627                 BTRFS_I(dir)->index_cnt--;
4628         btrfs_free_path(path);
4629         iput(inode);
4630         return ERR_PTR(ret);
4631 }
4632
4633 static inline u8 btrfs_inode_type(struct inode *inode)
4634 {
4635         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
4636 }
4637
4638 /*
4639  * utility function to add 'inode' into 'parent_inode' with
4640  * a give name and a given sequence number.
4641  * if 'add_backref' is true, also insert a backref from the
4642  * inode to the parent directory.
4643  */
4644 int btrfs_add_link(struct btrfs_trans_handle *trans,
4645                    struct inode *parent_inode, struct inode *inode,
4646                    const char *name, int name_len, int add_backref, u64 index)
4647 {
4648         int ret = 0;
4649         struct btrfs_key key;
4650         struct btrfs_root *root = BTRFS_I(parent_inode)->root;
4651
4652         if (unlikely(inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)) {
4653                 memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
4654         } else {
4655                 key.objectid = inode->i_ino;
4656                 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
4657                 key.offset = 0;
4658         }
4659
4660         if (unlikely(inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)) {
4661                 ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
4662                                          key.objectid, root->root_key.objectid,
4663                                          parent_inode->i_ino,
4664                                          index, name, name_len);
4665         } else if (add_backref) {
4666                 ret = btrfs_insert_inode_ref(trans, root,
4667                                              name, name_len, inode->i_ino,
4668                                              parent_inode->i_ino, index);
4669         }
4670
4671         if (ret == 0) {
4672                 ret = btrfs_insert_dir_item(trans, root, name, name_len,
4673                                             parent_inode->i_ino, &key,
4674                                             btrfs_inode_type(inode), index);
4675                 BUG_ON(ret);
4676
4677                 btrfs_i_size_write(parent_inode, parent_inode->i_size +
4678                                    name_len * 2);
4679                 parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
4680                 ret = btrfs_update_inode(trans, root, parent_inode);
4681         }
4682         return ret;
4683 }
4684
4685 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
4686                             struct inode *dir, struct dentry *dentry,
4687                             struct inode *inode, int backref, u64 index)
4688 {
4689         int err = btrfs_add_link(trans, dir, inode,
4690                                  dentry->d_name.name, dentry->d_name.len,
4691                                  backref, index);
4692         if (!err) {
4693                 d_instantiate(dentry, inode);
4694                 return 0;
4695         }
4696         if (err > 0)
4697                 err = -EEXIST;
4698         return err;
4699 }
4700
4701 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
4702                         int mode, dev_t rdev)
4703 {
4704         struct btrfs_trans_handle *trans;
4705         struct btrfs_root *root = BTRFS_I(dir)->root;
4706         struct inode *inode = NULL;
4707         int err;
4708         int drop_inode = 0;
4709         u64 objectid;
4710         unsigned long nr = 0;
4711         u64 index = 0;
4712
4713         if (!new_valid_dev(rdev))
4714                 return -EINVAL;
4715
4716         err = btrfs_find_free_objectid(NULL, root, dir->i_ino, &objectid);
4717         if (err)
4718                 return err;
4719
4720         /*
4721          * 2 for inode item and ref
4722          * 2 for dir items
4723          * 1 for xattr if selinux is on
4724          */
4725         trans = btrfs_start_transaction(root, 5);
4726         if (IS_ERR(trans))
4727                 return PTR_ERR(trans);
4728
4729         btrfs_set_trans_block_group(trans, dir);
4730
4731         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4732                                 dentry->d_name.len, dir->i_ino, objectid,
4733                                 BTRFS_I(dir)->block_group, mode, &index);
4734         err = PTR_ERR(inode);
4735         if (IS_ERR(inode))
4736                 goto out_unlock;
4737
4738         err = btrfs_init_inode_security(trans, inode, dir);
4739         if (err) {
4740                 drop_inode = 1;
4741                 goto out_unlock;
4742         }
4743
4744         btrfs_set_trans_block_group(trans, inode);
4745         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
4746         if (err)
4747                 drop_inode = 1;
4748         else {
4749                 inode->i_op = &btrfs_special_inode_operations;
4750                 init_special_inode(inode, inode->i_mode, rdev);
4751                 btrfs_update_inode(trans, root, inode);
4752         }
4753         btrfs_update_inode_block_group(trans, inode);
4754         btrfs_update_inode_block_group(trans, dir);
4755 out_unlock:
4756         nr = trans->blocks_used;
4757         btrfs_end_transaction_throttle(trans, root);
4758         btrfs_btree_balance_dirty(root, nr);
4759         if (drop_inode) {
4760                 inode_dec_link_count(inode);
4761                 iput(inode);
4762         }
4763         return err;
4764 }
4765
4766 static int btrfs_create(struct inode *dir, struct dentry *dentry,
4767                         int mode, struct nameidata *nd)
4768 {
4769         struct btrfs_trans_handle *trans;
4770         struct btrfs_root *root = BTRFS_I(dir)->root;
4771         struct inode *inode = NULL;
4772         int drop_inode = 0;
4773         int err;
4774         unsigned long nr = 0;
4775         u64 objectid;
4776         u64 index = 0;
4777
4778         err = btrfs_find_free_objectid(NULL, root, dir->i_ino, &objectid);
4779         if (err)
4780                 return err;
4781         /*
4782          * 2 for inode item and ref
4783          * 2 for dir items
4784          * 1 for xattr if selinux is on
4785          */
4786         trans = btrfs_start_transaction(root, 5);
4787         if (IS_ERR(trans))
4788                 return PTR_ERR(trans);
4789
4790         btrfs_set_trans_block_group(trans, dir);
4791
4792         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4793                                 dentry->d_name.len, dir->i_ino, objectid,
4794                                 BTRFS_I(dir)->block_group, mode, &index);
4795         err = PTR_ERR(inode);
4796         if (IS_ERR(inode))
4797                 goto out_unlock;
4798
4799         err = btrfs_init_inode_security(trans, inode, dir);
4800         if (err) {
4801                 drop_inode = 1;
4802                 goto out_unlock;
4803         }
4804
4805         btrfs_set_trans_block_group(trans, inode);
4806         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
4807         if (err)
4808                 drop_inode = 1;
4809         else {
4810                 inode->i_mapping->a_ops = &btrfs_aops;
4811                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
4812                 inode->i_fop = &btrfs_file_operations;
4813                 inode->i_op = &btrfs_file_inode_operations;
4814                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
4815         }
4816         btrfs_update_inode_block_group(trans, inode);
4817         btrfs_update_inode_block_group(trans, dir);
4818 out_unlock:
4819         nr = trans->blocks_used;
4820         btrfs_end_transaction_throttle(trans, root);
4821         if (drop_inode) {
4822                 inode_dec_link_count(inode);
4823                 iput(inode);
4824         }
4825         btrfs_btree_balance_dirty(root, nr);
4826         return err;
4827 }
4828
4829 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
4830                       struct dentry *dentry)
4831 {
4832         struct btrfs_trans_handle *trans;
4833         struct btrfs_root *root = BTRFS_I(dir)->root;
4834         struct inode *inode = old_dentry->d_inode;
4835         u64 index;
4836         unsigned long nr = 0;
4837         int err;
4838         int drop_inode = 0;
4839
4840         if (inode->i_nlink == 0)
4841                 return -ENOENT;
4842
4843         /* do not allow sys_link's with other subvols of the same device */
4844         if (root->objectid != BTRFS_I(inode)->root->objectid)
4845                 return -EXDEV;
4846
4847         if (inode->i_nlink == ~0U)
4848                 return -EMLINK;
4849
4850         err = btrfs_set_inode_index(dir, &index);
4851         if (err)
4852                 goto fail;
4853
4854         /*
4855          * 2 items for inode and inode ref
4856          * 2 items for dir items
4857          * 1 item for parent inode
4858          */
4859         trans = btrfs_start_transaction(root, 5);
4860         if (IS_ERR(trans)) {
4861                 err = PTR_ERR(trans);
4862                 goto fail;
4863         }
4864
4865         btrfs_inc_nlink(inode);
4866         inode->i_ctime = CURRENT_TIME;
4867
4868         btrfs_set_trans_block_group(trans, dir);
4869         ihold(inode);
4870
4871         err = btrfs_add_nondir(trans, dir, dentry, inode, 1, index);
4872
4873         if (err) {
4874                 drop_inode = 1;
4875         } else {
4876                 struct dentry *parent = dget_parent(dentry);
4877                 btrfs_update_inode_block_group(trans, dir);
4878                 err = btrfs_update_inode(trans, root, inode);
4879                 BUG_ON(err);
4880                 btrfs_log_new_name(trans, inode, NULL, parent);
4881                 dput(parent);
4882         }
4883
4884         nr = trans->blocks_used;
4885         btrfs_end_transaction_throttle(trans, root);
4886 fail:
4887         if (drop_inode) {
4888                 inode_dec_link_count(inode);
4889                 iput(inode);
4890         }
4891         btrfs_btree_balance_dirty(root, nr);
4892         return err;
4893 }
4894
4895 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
4896 {
4897         struct inode *inode = NULL;
4898         struct btrfs_trans_handle *trans;
4899         struct btrfs_root *root = BTRFS_I(dir)->root;
4900         int err = 0;
4901         int drop_on_err = 0;
4902         u64 objectid = 0;
4903         u64 index = 0;
4904         unsigned long nr = 1;
4905
4906         err = btrfs_find_free_objectid(NULL, root, dir->i_ino, &objectid);
4907         if (err)
4908                 return err;
4909
4910         /*
4911          * 2 items for inode and ref
4912          * 2 items for dir items
4913          * 1 for xattr if selinux is on
4914          */
4915         trans = btrfs_start_transaction(root, 5);
4916         if (IS_ERR(trans))
4917                 return PTR_ERR(trans);
4918         btrfs_set_trans_block_group(trans, dir);
4919
4920         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4921                                 dentry->d_name.len, dir->i_ino, objectid,
4922                                 BTRFS_I(dir)->block_group, S_IFDIR | mode,
4923                                 &index);
4924         if (IS_ERR(inode)) {
4925                 err = PTR_ERR(inode);
4926                 goto out_fail;
4927         }
4928
4929         drop_on_err = 1;
4930
4931         err = btrfs_init_inode_security(trans, inode, dir);
4932         if (err)
4933                 goto out_fail;
4934
4935         inode->i_op = &btrfs_dir_inode_operations;
4936         inode->i_fop = &btrfs_dir_file_operations;
4937         btrfs_set_trans_block_group(trans, inode);
4938
4939         btrfs_i_size_write(inode, 0);
4940         err = btrfs_update_inode(trans, root, inode);
4941         if (err)
4942                 goto out_fail;
4943
4944         err = btrfs_add_link(trans, dir, inode, dentry->d_name.name,
4945                              dentry->d_name.len, 0, index);
4946         if (err)
4947                 goto out_fail;
4948
4949         d_instantiate(dentry, inode);
4950         drop_on_err = 0;
4951         btrfs_update_inode_block_group(trans, inode);
4952         btrfs_update_inode_block_group(trans, dir);
4953
4954 out_fail:
4955         nr = trans->blocks_used;
4956         btrfs_end_transaction_throttle(trans, root);
4957         if (drop_on_err)
4958                 iput(inode);
4959         btrfs_btree_balance_dirty(root, nr);
4960         return err;
4961 }
4962
4963 /* helper for btfs_get_extent.  Given an existing extent in the tree,
4964  * and an extent that you want to insert, deal with overlap and insert
4965  * the new extent into the tree.
4966  */
4967 static int merge_extent_mapping(struct extent_map_tree *em_tree,
4968                                 struct extent_map *existing,
4969                                 struct extent_map *em,
4970                                 u64 map_start, u64 map_len)
4971 {
4972         u64 start_diff;
4973
4974         BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
4975         start_diff = map_start - em->start;
4976         em->start = map_start;
4977         em->len = map_len;
4978         if (em->block_start < EXTENT_MAP_LAST_BYTE &&
4979             !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
4980                 em->block_start += start_diff;
4981                 em->block_len -= start_diff;
4982         }
4983         return add_extent_mapping(em_tree, em);
4984 }
4985
4986 static noinline int uncompress_inline(struct btrfs_path *path,
4987                                       struct inode *inode, struct page *page,
4988                                       size_t pg_offset, u64 extent_offset,
4989                                       struct btrfs_file_extent_item *item)
4990 {
4991         int ret;
4992         struct extent_buffer *leaf = path->nodes[0];
4993         char *tmp;
4994         size_t max_size;
4995         unsigned long inline_size;
4996         unsigned long ptr;
4997         int compress_type;
4998
4999         WARN_ON(pg_offset != 0);
5000         compress_type = btrfs_file_extent_compression(leaf, item);
5001         max_size = btrfs_file_extent_ram_bytes(leaf, item);
5002         inline_size = btrfs_file_extent_inline_item_len(leaf,
5003                                         btrfs_item_nr(leaf, path->slots[0]));
5004         tmp = kmalloc(inline_size, GFP_NOFS);
5005         if (!tmp)
5006                 return -ENOMEM;
5007         ptr = btrfs_file_extent_inline_start(item);
5008
5009         read_extent_buffer(leaf, tmp, ptr, inline_size);
5010
5011         max_size = min_t(unsigned long, PAGE_CACHE_SIZE, max_size);
5012         ret = btrfs_decompress(compress_type, tmp, page,
5013                                extent_offset, inline_size, max_size);
5014         if (ret) {
5015                 char *kaddr = kmap_atomic(page, KM_USER0);
5016                 unsigned long copy_size = min_t(u64,
5017                                   PAGE_CACHE_SIZE - pg_offset,
5018                                   max_size - extent_offset);
5019                 memset(kaddr + pg_offset, 0, copy_size);
5020                 kunmap_atomic(kaddr, KM_USER0);
5021         }
5022         kfree(tmp);
5023         return 0;
5024 }
5025
5026 /*
5027  * a bit scary, this does extent mapping from logical file offset to the disk.
5028  * the ugly parts come from merging extents from the disk with the in-ram
5029  * representation.  This gets more complex because of the data=ordered code,
5030  * where the in-ram extents might be locked pending data=ordered completion.
5031  *
5032  * This also copies inline extents directly into the page.
5033  */
5034
5035 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
5036                                     size_t pg_offset, u64 start, u64 len,
5037                                     int create)
5038 {
5039         int ret;
5040         int err = 0;
5041         u64 bytenr;
5042         u64 extent_start = 0;
5043         u64 extent_end = 0;
5044         u64 objectid = inode->i_ino;
5045         u32 found_type;
5046         struct btrfs_path *path = NULL;
5047         struct btrfs_root *root = BTRFS_I(inode)->root;
5048         struct btrfs_file_extent_item *item;
5049         struct extent_buffer *leaf;
5050         struct btrfs_key found_key;
5051         struct extent_map *em = NULL;
5052         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
5053         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
5054         struct btrfs_trans_handle *trans = NULL;
5055         int compress_type;
5056
5057 again:
5058         read_lock(&em_tree->lock);
5059         em = lookup_extent_mapping(em_tree, start, len);
5060         if (em)
5061                 em->bdev = root->fs_info->fs_devices->latest_bdev;
5062         read_unlock(&em_tree->lock);
5063
5064         if (em) {
5065                 if (em->start > start || em->start + em->len <= start)
5066                         free_extent_map(em);
5067                 else if (em->block_start == EXTENT_MAP_INLINE && page)
5068                         free_extent_map(em);
5069                 else
5070                         goto out;
5071         }
5072         em = alloc_extent_map(GFP_NOFS);
5073         if (!em) {
5074                 err = -ENOMEM;
5075                 goto out;
5076         }
5077         em->bdev = root->fs_info->fs_devices->latest_bdev;
5078         em->start = EXTENT_MAP_HOLE;
5079         em->orig_start = EXTENT_MAP_HOLE;
5080         em->len = (u64)-1;
5081         em->block_len = (u64)-1;
5082
5083         if (!path) {
5084                 path = btrfs_alloc_path();
5085                 BUG_ON(!path);
5086         }
5087
5088         ret = btrfs_lookup_file_extent(trans, root, path,
5089                                        objectid, start, trans != NULL);
5090         if (ret < 0) {
5091                 err = ret;
5092                 goto out;
5093         }
5094
5095         if (ret != 0) {
5096                 if (path->slots[0] == 0)
5097                         goto not_found;
5098                 path->slots[0]--;
5099         }
5100
5101         leaf = path->nodes[0];
5102         item = btrfs_item_ptr(leaf, path->slots[0],
5103                               struct btrfs_file_extent_item);
5104         /* are we inside the extent that was found? */
5105         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5106         found_type = btrfs_key_type(&found_key);
5107         if (found_key.objectid != objectid ||
5108             found_type != BTRFS_EXTENT_DATA_KEY) {
5109                 goto not_found;
5110         }
5111
5112         found_type = btrfs_file_extent_type(leaf, item);
5113         extent_start = found_key.offset;
5114         compress_type = btrfs_file_extent_compression(leaf, item);
5115         if (found_type == BTRFS_FILE_EXTENT_REG ||
5116             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
5117                 extent_end = extent_start +
5118                        btrfs_file_extent_num_bytes(leaf, item);
5119         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
5120                 size_t size;
5121                 size = btrfs_file_extent_inline_len(leaf, item);
5122                 extent_end = (extent_start + size + root->sectorsize - 1) &
5123                         ~((u64)root->sectorsize - 1);
5124         }
5125
5126         if (start >= extent_end) {
5127                 path->slots[0]++;
5128                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
5129                         ret = btrfs_next_leaf(root, path);
5130                         if (ret < 0) {
5131                                 err = ret;
5132                                 goto out;
5133                         }
5134                         if (ret > 0)
5135                                 goto not_found;
5136                         leaf = path->nodes[0];
5137                 }
5138                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5139                 if (found_key.objectid != objectid ||
5140                     found_key.type != BTRFS_EXTENT_DATA_KEY)
5141                         goto not_found;
5142                 if (start + len <= found_key.offset)
5143                         goto not_found;
5144                 em->start = start;
5145                 em->len = found_key.offset - start;
5146                 goto not_found_em;
5147         }
5148
5149         if (found_type == BTRFS_FILE_EXTENT_REG ||
5150             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
5151                 em->start = extent_start;
5152                 em->len = extent_end - extent_start;
5153                 em->orig_start = extent_start -
5154                                  btrfs_file_extent_offset(leaf, item);
5155                 bytenr = btrfs_file_extent_disk_bytenr(leaf, item);
5156                 if (bytenr == 0) {
5157                         em->block_start = EXTENT_MAP_HOLE;
5158                         goto insert;
5159                 }
5160                 if (compress_type != BTRFS_COMPRESS_NONE) {
5161                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
5162                         em->compress_type = compress_type;
5163                         em->block_start = bytenr;
5164                         em->block_len = btrfs_file_extent_disk_num_bytes(leaf,
5165                                                                          item);
5166                 } else {
5167                         bytenr += btrfs_file_extent_offset(leaf, item);
5168                         em->block_start = bytenr;
5169                         em->block_len = em->len;
5170                         if (found_type == BTRFS_FILE_EXTENT_PREALLOC)
5171                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
5172                 }
5173                 goto insert;
5174         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
5175                 unsigned long ptr;
5176                 char *map;
5177                 size_t size;
5178                 size_t extent_offset;
5179                 size_t copy_size;
5180
5181                 em->block_start = EXTENT_MAP_INLINE;
5182                 if (!page || create) {
5183                         em->start = extent_start;
5184                         em->len = extent_end - extent_start;
5185                         goto out;
5186                 }
5187
5188                 size = btrfs_file_extent_inline_len(leaf, item);
5189                 extent_offset = page_offset(page) + pg_offset - extent_start;
5190                 copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
5191                                 size - extent_offset);
5192                 em->start = extent_start + extent_offset;
5193                 em->len = (copy_size + root->sectorsize - 1) &
5194                         ~((u64)root->sectorsize - 1);
5195                 em->orig_start = EXTENT_MAP_INLINE;
5196                 if (compress_type) {
5197                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
5198                         em->compress_type = compress_type;
5199                 }
5200                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
5201                 if (create == 0 && !PageUptodate(page)) {
5202                         if (btrfs_file_extent_compression(leaf, item) !=
5203                             BTRFS_COMPRESS_NONE) {
5204                                 ret = uncompress_inline(path, inode, page,
5205                                                         pg_offset,
5206                                                         extent_offset, item);
5207                                 BUG_ON(ret);
5208                         } else {
5209                                 map = kmap(page);
5210                                 read_extent_buffer(leaf, map + pg_offset, ptr,
5211                                                    copy_size);
5212                                 if (pg_offset + copy_size < PAGE_CACHE_SIZE) {
5213                                         memset(map + pg_offset + copy_size, 0,
5214                                                PAGE_CACHE_SIZE - pg_offset -
5215                                                copy_size);
5216                                 }
5217                                 kunmap(page);
5218                         }
5219                         flush_dcache_page(page);
5220                 } else if (create && PageUptodate(page)) {
5221                         WARN_ON(1);
5222                         if (!trans) {
5223                                 kunmap(page);
5224                                 free_extent_map(em);
5225                                 em = NULL;
5226                                 btrfs_release_path(root, path);
5227                                 trans = btrfs_join_transaction(root, 1);
5228                                 if (IS_ERR(trans))
5229                                         return ERR_CAST(trans);
5230                                 goto again;
5231                         }
5232                         map = kmap(page);
5233                         write_extent_buffer(leaf, map + pg_offset, ptr,
5234                                             copy_size);
5235                         kunmap(page);
5236                         btrfs_mark_buffer_dirty(leaf);
5237                 }
5238                 set_extent_uptodate(io_tree, em->start,
5239                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
5240                 goto insert;
5241         } else {
5242                 printk(KERN_ERR "btrfs unknown found_type %d\n", found_type);
5243                 WARN_ON(1);
5244         }
5245 not_found:
5246         em->start = start;
5247         em->len = len;
5248 not_found_em:
5249         em->block_start = EXTENT_MAP_HOLE;
5250         set_bit(EXTENT_FLAG_VACANCY, &em->flags);
5251 insert:
5252         btrfs_release_path(root, path);
5253         if (em->start > start || extent_map_end(em) <= start) {
5254                 printk(KERN_ERR "Btrfs: bad extent! em: [%llu %llu] passed "
5255                        "[%llu %llu]\n", (unsigned long long)em->start,
5256                        (unsigned long long)em->len,
5257                        (unsigned long long)start,
5258                        (unsigned long long)len);
5259                 err = -EIO;
5260                 goto out;
5261         }
5262
5263         err = 0;
5264         write_lock(&em_tree->lock);
5265         ret = add_extent_mapping(em_tree, em);
5266         /* it is possible that someone inserted the extent into the tree
5267          * while we had the lock dropped.  It is also possible that
5268          * an overlapping map exists in the tree
5269          */
5270         if (ret == -EEXIST) {
5271                 struct extent_map *existing;
5272
5273                 ret = 0;
5274
5275                 existing = lookup_extent_mapping(em_tree, start, len);
5276                 if (existing && (existing->start > start ||
5277                     existing->start + existing->len <= start)) {
5278                         free_extent_map(existing);
5279                         existing = NULL;
5280                 }
5281                 if (!existing) {
5282                         existing = lookup_extent_mapping(em_tree, em->start,
5283                                                          em->len);
5284                         if (existing) {
5285                                 err = merge_extent_mapping(em_tree, existing,
5286                                                            em, start,
5287                                                            root->sectorsize);
5288                                 free_extent_map(existing);
5289                                 if (err) {
5290                                         free_extent_map(em);
5291                                         em = NULL;
5292                                 }
5293                         } else {
5294                                 err = -EIO;
5295                                 free_extent_map(em);
5296                                 em = NULL;
5297                         }
5298                 } else {
5299                         free_extent_map(em);
5300                         em = existing;
5301                         err = 0;
5302                 }
5303         }
5304         write_unlock(&em_tree->lock);
5305 out:
5306
5307         trace_btrfs_get_extent(root, em);
5308
5309         if (path)
5310                 btrfs_free_path(path);
5311         if (trans) {
5312                 ret = btrfs_end_transaction(trans, root);
5313                 if (!err)
5314                         err = ret;
5315         }
5316         if (err) {
5317                 free_extent_map(em);
5318                 return ERR_PTR(err);
5319         }
5320         return em;
5321 }
5322
5323 struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
5324                                            size_t pg_offset, u64 start, u64 len,
5325                                            int create)
5326 {
5327         struct extent_map *em;
5328         struct extent_map *hole_em = NULL;
5329         u64 range_start = start;
5330         u64 end;
5331         u64 found;
5332         u64 found_end;
5333         int err = 0;
5334
5335         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
5336         if (IS_ERR(em))
5337                 return em;
5338         if (em) {
5339                 /*
5340                  * if our em maps to a hole, there might
5341                  * actually be delalloc bytes behind it
5342                  */
5343                 if (em->block_start != EXTENT_MAP_HOLE)
5344                         return em;
5345                 else
5346                         hole_em = em;
5347         }
5348
5349         /* check to see if we've wrapped (len == -1 or similar) */
5350         end = start + len;
5351         if (end < start)
5352                 end = (u64)-1;
5353         else
5354                 end -= 1;
5355
5356         em = NULL;
5357
5358         /* ok, we didn't find anything, lets look for delalloc */
5359         found = count_range_bits(&BTRFS_I(inode)->io_tree, &range_start,
5360                                  end, len, EXTENT_DELALLOC, 1);
5361         found_end = range_start + found;
5362         if (found_end < range_start)
5363                 found_end = (u64)-1;
5364
5365         /*
5366          * we didn't find anything useful, return
5367          * the original results from get_extent()
5368          */
5369         if (range_start > end || found_end <= start) {
5370                 em = hole_em;
5371                 hole_em = NULL;
5372                 goto out;
5373         }
5374
5375         /* adjust the range_start to make sure it doesn't
5376          * go backwards from the start they passed in
5377          */
5378         range_start = max(start,range_start);
5379         found = found_end - range_start;
5380
5381         if (found > 0) {
5382                 u64 hole_start = start;
5383                 u64 hole_len = len;
5384
5385                 em = alloc_extent_map(GFP_NOFS);
5386                 if (!em) {
5387                         err = -ENOMEM;
5388                         goto out;
5389                 }
5390                 /*
5391                  * when btrfs_get_extent can't find anything it
5392                  * returns one huge hole
5393                  *
5394                  * make sure what it found really fits our range, and
5395                  * adjust to make sure it is based on the start from
5396                  * the caller
5397                  */
5398                 if (hole_em) {
5399                         u64 calc_end = extent_map_end(hole_em);
5400
5401                         if (calc_end <= start || (hole_em->start > end)) {
5402                                 free_extent_map(hole_em);
5403                                 hole_em = NULL;
5404                         } else {
5405                                 hole_start = max(hole_em->start, start);
5406                                 hole_len = calc_end - hole_start;
5407                         }
5408                 }
5409                 em->bdev = NULL;
5410                 if (hole_em && range_start > hole_start) {
5411                         /* our hole starts before our delalloc, so we
5412                          * have to return just the parts of the hole
5413                          * that go until  the delalloc starts
5414                          */
5415                         em->len = min(hole_len,
5416                                       range_start - hole_start);
5417                         em->start = hole_start;
5418                         em->orig_start = hole_start;
5419                         /*
5420                          * don't adjust block start at all,
5421                          * it is fixed at EXTENT_MAP_HOLE
5422                          */
5423                         em->block_start = hole_em->block_start;
5424                         em->block_len = hole_len;
5425                 } else {
5426                         em->start = range_start;
5427                         em->len = found;
5428                         em->orig_start = range_start;
5429                         em->block_start = EXTENT_MAP_DELALLOC;
5430                         em->block_len = found;
5431                 }
5432         } else if (hole_em) {
5433                 return hole_em;
5434         }
5435 out:
5436
5437         free_extent_map(hole_em);
5438         if (err) {
5439                 free_extent_map(em);
5440                 return ERR_PTR(err);
5441         }
5442         return em;
5443 }
5444
5445 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
5446                                                   struct extent_map *em,
5447                                                   u64 start, u64 len)
5448 {
5449         struct btrfs_root *root = BTRFS_I(inode)->root;
5450         struct btrfs_trans_handle *trans;
5451         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
5452         struct btrfs_key ins;
5453         u64 alloc_hint;
5454         int ret;
5455         bool insert = false;
5456
5457         /*
5458          * Ok if the extent map we looked up is a hole and is for the exact
5459          * range we want, there is no reason to allocate a new one, however if
5460          * it is not right then we need to free this one and drop the cache for
5461          * our range.
5462          */
5463         if (em->block_start != EXTENT_MAP_HOLE || em->start != start ||
5464             em->len != len) {
5465                 free_extent_map(em);
5466                 em = NULL;
5467                 insert = true;
5468                 btrfs_drop_extent_cache(inode, start, start + len - 1, 0);
5469         }
5470
5471         trans = btrfs_join_transaction(root, 0);
5472         if (IS_ERR(trans))
5473                 return ERR_CAST(trans);
5474
5475         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
5476
5477         alloc_hint = get_extent_allocation_hint(inode, start, len);
5478         ret = btrfs_reserve_extent(trans, root, len, root->sectorsize, 0,
5479                                    alloc_hint, (u64)-1, &ins, 1);
5480         if (ret) {
5481                 em = ERR_PTR(ret);
5482                 goto out;
5483         }
5484
5485         if (!em) {
5486                 em = alloc_extent_map(GFP_NOFS);
5487                 if (!em) {
5488                         em = ERR_PTR(-ENOMEM);
5489                         goto out;
5490                 }
5491         }
5492
5493         em->start = start;
5494         em->orig_start = em->start;
5495         em->len = ins.offset;
5496
5497         em->block_start = ins.objectid;
5498         em->block_len = ins.offset;
5499         em->bdev = root->fs_info->fs_devices->latest_bdev;
5500
5501         /*
5502          * We need to do this because if we're using the original em we searched
5503          * for, we could have EXTENT_FLAG_VACANCY set, and we don't want that.
5504          */
5505         em->flags = 0;
5506         set_bit(EXTENT_FLAG_PINNED, &em->flags);
5507
5508         while (insert) {
5509                 write_lock(&em_tree->lock);
5510                 ret = add_extent_mapping(em_tree, em);
5511                 write_unlock(&em_tree->lock);
5512                 if (ret != -EEXIST)
5513                         break;
5514                 btrfs_drop_extent_cache(inode, start, start + em->len - 1, 0);
5515         }
5516
5517         ret = btrfs_add_ordered_extent_dio(inode, start, ins.objectid,
5518                                            ins.offset, ins.offset, 0);
5519         if (ret) {
5520                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
5521                 em = ERR_PTR(ret);
5522         }
5523 out:
5524         btrfs_end_transaction(trans, root);
5525         return em;
5526 }
5527
5528 /*
5529  * returns 1 when the nocow is safe, < 1 on error, 0 if the
5530  * block must be cow'd
5531  */
5532 static noinline int can_nocow_odirect(struct btrfs_trans_handle *trans,
5533                                       struct inode *inode, u64 offset, u64 len)
5534 {
5535         struct btrfs_path *path;
5536         int ret;
5537         struct extent_buffer *leaf;
5538         struct btrfs_root *root = BTRFS_I(inode)->root;
5539         struct btrfs_file_extent_item *fi;
5540         struct btrfs_key key;
5541         u64 disk_bytenr;
5542         u64 backref_offset;
5543         u64 extent_end;
5544         u64 num_bytes;
5545         int slot;
5546         int found_type;
5547
5548         path = btrfs_alloc_path();
5549         if (!path)
5550                 return -ENOMEM;
5551
5552         ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
5553                                        offset, 0);
5554         if (ret < 0)
5555                 goto out;
5556
5557         slot = path->slots[0];
5558         if (ret == 1) {
5559                 if (slot == 0) {
5560                         /* can't find the item, must cow */
5561                         ret = 0;
5562                         goto out;
5563                 }
5564                 slot--;
5565         }
5566         ret = 0;
5567         leaf = path->nodes[0];
5568         btrfs_item_key_to_cpu(leaf, &key, slot);
5569         if (key.objectid != inode->i_ino ||
5570             key.type != BTRFS_EXTENT_DATA_KEY) {
5571                 /* not our file or wrong item type, must cow */
5572                 goto out;
5573         }
5574
5575         if (key.offset > offset) {
5576                 /* Wrong offset, must cow */
5577                 goto out;
5578         }
5579
5580         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
5581         found_type = btrfs_file_extent_type(leaf, fi);
5582         if (found_type != BTRFS_FILE_EXTENT_REG &&
5583             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
5584                 /* not a regular extent, must cow */
5585                 goto out;
5586         }
5587         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
5588         backref_offset = btrfs_file_extent_offset(leaf, fi);
5589
5590         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
5591         if (extent_end < offset + len) {
5592                 /* extent doesn't include our full range, must cow */
5593                 goto out;
5594         }
5595
5596         if (btrfs_extent_readonly(root, disk_bytenr))
5597                 goto out;
5598
5599         /*
5600          * look for other files referencing this extent, if we
5601          * find any we must cow
5602          */
5603         if (btrfs_cross_ref_exist(trans, root, inode->i_ino,
5604                                   key.offset - backref_offset, disk_bytenr))
5605                 goto out;
5606
5607         /*
5608          * adjust disk_bytenr and num_bytes to cover just the bytes
5609          * in this extent we are about to write.  If there
5610          * are any csums in that range we have to cow in order
5611          * to keep the csums correct
5612          */
5613         disk_bytenr += backref_offset;
5614         disk_bytenr += offset - key.offset;
5615         num_bytes = min(offset + len, extent_end) - offset;
5616         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
5617                                 goto out;
5618         /*
5619          * all of the above have passed, it is safe to overwrite this extent
5620          * without cow
5621          */
5622         ret = 1;
5623 out:
5624         btrfs_free_path(path);
5625         return ret;
5626 }
5627
5628 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
5629                                    struct buffer_head *bh_result, int create)
5630 {
5631         struct extent_map *em;
5632         struct btrfs_root *root = BTRFS_I(inode)->root;
5633         u64 start = iblock << inode->i_blkbits;
5634         u64 len = bh_result->b_size;
5635         struct btrfs_trans_handle *trans;
5636
5637         em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
5638         if (IS_ERR(em))
5639                 return PTR_ERR(em);
5640
5641         /*
5642          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
5643          * io.  INLINE is special, and we could probably kludge it in here, but
5644          * it's still buffered so for safety lets just fall back to the generic
5645          * buffered path.
5646          *
5647          * For COMPRESSED we _have_ to read the entire extent in so we can
5648          * decompress it, so there will be buffering required no matter what we
5649          * do, so go ahead and fallback to buffered.
5650          *
5651          * We return -ENOTBLK because thats what makes DIO go ahead and go back
5652          * to buffered IO.  Don't blame me, this is the price we pay for using
5653          * the generic code.
5654          */
5655         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
5656             em->block_start == EXTENT_MAP_INLINE) {
5657                 free_extent_map(em);
5658                 return -ENOTBLK;
5659         }
5660
5661         /* Just a good old fashioned hole, return */
5662         if (!create && (em->block_start == EXTENT_MAP_HOLE ||
5663                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
5664                 free_extent_map(em);
5665                 /* DIO will do one hole at a time, so just unlock a sector */
5666                 unlock_extent(&BTRFS_I(inode)->io_tree, start,
5667                               start + root->sectorsize - 1, GFP_NOFS);
5668                 return 0;
5669         }
5670
5671         /*
5672          * We don't allocate a new extent in the following cases
5673          *
5674          * 1) The inode is marked as NODATACOW.  In this case we'll just use the
5675          * existing extent.
5676          * 2) The extent is marked as PREALLOC.  We're good to go here and can
5677          * just use the extent.
5678          *
5679          */
5680         if (!create) {
5681                 len = em->len - (start - em->start);
5682                 goto map;
5683         }
5684
5685         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
5686             ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
5687              em->block_start != EXTENT_MAP_HOLE)) {
5688                 int type;
5689                 int ret;
5690                 u64 block_start;
5691
5692                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
5693                         type = BTRFS_ORDERED_PREALLOC;
5694                 else
5695                         type = BTRFS_ORDERED_NOCOW;
5696                 len = min(len, em->len - (start - em->start));
5697                 block_start = em->block_start + (start - em->start);
5698
5699                 /*
5700                  * we're not going to log anything, but we do need
5701                  * to make sure the current transaction stays open
5702                  * while we look for nocow cross refs
5703                  */
5704                 trans = btrfs_join_transaction(root, 0);
5705                 if (IS_ERR(trans))
5706                         goto must_cow;
5707
5708                 if (can_nocow_odirect(trans, inode, start, len) == 1) {
5709                         ret = btrfs_add_ordered_extent_dio(inode, start,
5710                                            block_start, len, len, type);
5711                         btrfs_end_transaction(trans, root);
5712                         if (ret) {
5713                                 free_extent_map(em);
5714                                 return ret;
5715                         }
5716                         goto unlock;
5717                 }
5718                 btrfs_end_transaction(trans, root);
5719         }
5720 must_cow:
5721         /*
5722          * this will cow the extent, reset the len in case we changed
5723          * it above
5724          */
5725         len = bh_result->b_size;
5726         em = btrfs_new_extent_direct(inode, em, start, len);
5727         if (IS_ERR(em))
5728                 return PTR_ERR(em);
5729         len = min(len, em->len - (start - em->start));
5730 unlock:
5731         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, start + len - 1,
5732                           EXTENT_LOCKED | EXTENT_DELALLOC | EXTENT_DIRTY, 1,
5733                           0, NULL, GFP_NOFS);
5734 map:
5735         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
5736                 inode->i_blkbits;
5737         bh_result->b_size = len;
5738         bh_result->b_bdev = em->bdev;
5739         set_buffer_mapped(bh_result);
5740         if (create && !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
5741                 set_buffer_new(bh_result);
5742
5743         free_extent_map(em);
5744
5745         return 0;
5746 }
5747
5748 struct btrfs_dio_private {
5749         struct inode *inode;
5750         u64 logical_offset;
5751         u64 disk_bytenr;
5752         u64 bytes;
5753         u32 *csums;
5754         void *private;
5755
5756         /* number of bios pending for this dio */
5757         atomic_t pending_bios;
5758
5759         /* IO errors */
5760         int errors;
5761
5762         struct bio *orig_bio;
5763 };
5764
5765 static void btrfs_endio_direct_read(struct bio *bio, int err)
5766 {
5767         struct btrfs_dio_private *dip = bio->bi_private;
5768         struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1;
5769         struct bio_vec *bvec = bio->bi_io_vec;
5770         struct inode *inode = dip->inode;
5771         struct btrfs_root *root = BTRFS_I(inode)->root;
5772         u64 start;
5773         u32 *private = dip->csums;
5774
5775         start = dip->logical_offset;
5776         do {
5777                 if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
5778                         struct page *page = bvec->bv_page;
5779                         char *kaddr;
5780                         u32 csum = ~(u32)0;
5781                         unsigned long flags;
5782
5783                         local_irq_save(flags);
5784                         kaddr = kmap_atomic(page, KM_IRQ0);
5785                         csum = btrfs_csum_data(root, kaddr + bvec->bv_offset,
5786                                                csum, bvec->bv_len);
5787                         btrfs_csum_final(csum, (char *)&csum);
5788                         kunmap_atomic(kaddr, KM_IRQ0);
5789                         local_irq_restore(flags);
5790
5791                         flush_dcache_page(bvec->bv_page);
5792                         if (csum != *private) {
5793                                 printk(KERN_ERR "btrfs csum failed ino %lu off"
5794                                       " %llu csum %u private %u\n",
5795                                       inode->i_ino, (unsigned long long)start,
5796                                       csum, *private);
5797                                 err = -EIO;
5798                         }
5799                 }
5800
5801                 start += bvec->bv_len;
5802                 private++;
5803                 bvec++;
5804         } while (bvec <= bvec_end);
5805
5806         unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
5807                       dip->logical_offset + dip->bytes - 1, GFP_NOFS);
5808         bio->bi_private = dip->private;
5809
5810         kfree(dip->csums);
5811         kfree(dip);
5812
5813         /* If we had a csum failure make sure to clear the uptodate flag */
5814         if (err)
5815                 clear_bit(BIO_UPTODATE, &bio->bi_flags);
5816         dio_end_io(bio, err);
5817 }
5818
5819 static void btrfs_endio_direct_write(struct bio *bio, int err)
5820 {
5821         struct btrfs_dio_private *dip = bio->bi_private;
5822         struct inode *inode = dip->inode;
5823         struct btrfs_root *root = BTRFS_I(inode)->root;
5824         struct btrfs_trans_handle *trans;
5825         struct btrfs_ordered_extent *ordered = NULL;
5826         struct extent_state *cached_state = NULL;
5827         u64 ordered_offset = dip->logical_offset;
5828         u64 ordered_bytes = dip->bytes;
5829         int ret;
5830
5831         if (err)
5832                 goto out_done;
5833 again:
5834         ret = btrfs_dec_test_first_ordered_pending(inode, &ordered,
5835                                                    &ordered_offset,
5836                                                    ordered_bytes);
5837         if (!ret)
5838                 goto out_test;
5839
5840         BUG_ON(!ordered);
5841
5842         trans = btrfs_join_transaction(root, 1);
5843         if (IS_ERR(trans)) {
5844                 err = -ENOMEM;
5845                 goto out;
5846         }
5847         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
5848
5849         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered->flags)) {
5850                 ret = btrfs_ordered_update_i_size(inode, 0, ordered);
5851                 if (!ret)
5852                         ret = btrfs_update_inode(trans, root, inode);
5853                 err = ret;
5854                 goto out;
5855         }
5856
5857         lock_extent_bits(&BTRFS_I(inode)->io_tree, ordered->file_offset,
5858                          ordered->file_offset + ordered->len - 1, 0,
5859                          &cached_state, GFP_NOFS);
5860
5861         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered->flags)) {
5862                 ret = btrfs_mark_extent_written(trans, inode,
5863                                                 ordered->file_offset,
5864                                                 ordered->file_offset +
5865                                                 ordered->len);
5866                 if (ret) {
5867                         err = ret;
5868                         goto out_unlock;
5869                 }
5870         } else {
5871                 ret = insert_reserved_file_extent(trans, inode,
5872                                                   ordered->file_offset,
5873                                                   ordered->start,
5874                                                   ordered->disk_len,
5875                                                   ordered->len,
5876                                                   ordered->len,
5877                                                   0, 0, 0,
5878                                                   BTRFS_FILE_EXTENT_REG);
5879                 unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
5880                                    ordered->file_offset, ordered->len);
5881                 if (ret) {
5882                         err = ret;
5883                         WARN_ON(1);
5884                         goto out_unlock;
5885                 }
5886         }
5887
5888         add_pending_csums(trans, inode, ordered->file_offset, &ordered->list);
5889         ret = btrfs_ordered_update_i_size(inode, 0, ordered);
5890         if (!ret)
5891                 btrfs_update_inode(trans, root, inode);
5892         ret = 0;
5893 out_unlock:
5894         unlock_extent_cached(&BTRFS_I(inode)->io_tree, ordered->file_offset,
5895                              ordered->file_offset + ordered->len - 1,
5896                              &cached_state, GFP_NOFS);
5897 out:
5898         btrfs_delalloc_release_metadata(inode, ordered->len);
5899         btrfs_end_transaction(trans, root);
5900         ordered_offset = ordered->file_offset + ordered->len;
5901         btrfs_put_ordered_extent(ordered);
5902         btrfs_put_ordered_extent(ordered);
5903
5904 out_test:
5905         /*
5906          * our bio might span multiple ordered extents.  If we haven't
5907          * completed the accounting for the whole dio, go back and try again
5908          */
5909         if (ordered_offset < dip->logical_offset + dip->bytes) {
5910                 ordered_bytes = dip->logical_offset + dip->bytes -
5911                         ordered_offset;
5912                 goto again;
5913         }
5914 out_done:
5915         bio->bi_private = dip->private;
5916
5917         kfree(dip->csums);
5918         kfree(dip);
5919
5920         /* If we had an error make sure to clear the uptodate flag */
5921         if (err)
5922                 clear_bit(BIO_UPTODATE, &bio->bi_flags);
5923         dio_end_io(bio, err);
5924 }
5925
5926 static int __btrfs_submit_bio_start_direct_io(struct inode *inode, int rw,
5927                                     struct bio *bio, int mirror_num,
5928                                     unsigned long bio_flags, u64 offset)
5929 {
5930         int ret;
5931         struct btrfs_root *root = BTRFS_I(inode)->root;
5932         ret = btrfs_csum_one_bio(root, inode, bio, offset, 1);
5933         BUG_ON(ret);
5934         return 0;
5935 }
5936
5937 static void btrfs_end_dio_bio(struct bio *bio, int err)
5938 {
5939         struct btrfs_dio_private *dip = bio->bi_private;
5940
5941         if (err) {
5942                 printk(KERN_ERR "btrfs direct IO failed ino %lu rw %lu "
5943                       "sector %#Lx len %u err no %d\n",
5944                       dip->inode->i_ino, bio->bi_rw,
5945                       (unsigned long long)bio->bi_sector, bio->bi_size, err);
5946                 dip->errors = 1;
5947
5948                 /*
5949                  * before atomic variable goto zero, we must make sure
5950                  * dip->errors is perceived to be set.
5951                  */
5952                 smp_mb__before_atomic_dec();
5953         }
5954
5955         /* if there are more bios still pending for this dio, just exit */
5956         if (!atomic_dec_and_test(&dip->pending_bios))
5957                 goto out;
5958
5959         if (dip->errors)
5960                 bio_io_error(dip->orig_bio);
5961         else {
5962                 set_bit(BIO_UPTODATE, &dip->orig_bio->bi_flags);
5963                 bio_endio(dip->orig_bio, 0);
5964         }
5965 out:
5966         bio_put(bio);
5967 }
5968
5969 static struct bio *btrfs_dio_bio_alloc(struct block_device *bdev,
5970                                        u64 first_sector, gfp_t gfp_flags)
5971 {
5972         int nr_vecs = bio_get_nr_vecs(bdev);
5973         return btrfs_bio_alloc(bdev, first_sector, nr_vecs, gfp_flags);
5974 }
5975
5976 static inline int __btrfs_submit_dio_bio(struct bio *bio, struct inode *inode,
5977                                          int rw, u64 file_offset, int skip_sum,
5978                                          u32 *csums, int async_submit)
5979 {
5980         int write = rw & REQ_WRITE;
5981         struct btrfs_root *root = BTRFS_I(inode)->root;
5982         int ret;
5983
5984         bio_get(bio);
5985         ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
5986         if (ret)
5987                 goto err;
5988
5989         if (skip_sum)
5990                 goto map;
5991
5992         if (write && async_submit) {
5993                 ret = btrfs_wq_submit_bio(root->fs_info,
5994                                    inode, rw, bio, 0, 0,
5995                                    file_offset,
5996                                    __btrfs_submit_bio_start_direct_io,
5997                                    __btrfs_submit_bio_done);
5998                 goto err;
5999         } else if (write) {
6000                 /*
6001                  * If we aren't doing async submit, calculate the csum of the
6002                  * bio now.
6003                  */
6004                 ret = btrfs_csum_one_bio(root, inode, bio, file_offset, 1);
6005                 if (ret)
6006                         goto err;
6007         } else if (!skip_sum) {
6008                 ret = btrfs_lookup_bio_sums_dio(root, inode, bio,
6009                                           file_offset, csums);
6010                 if (ret)
6011                         goto err;
6012         }
6013
6014 map:
6015         ret = btrfs_map_bio(root, rw, bio, 0, async_submit);
6016 err:
6017         bio_put(bio);
6018         return ret;
6019 }
6020
6021 static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip,
6022                                     int skip_sum)
6023 {
6024         struct inode *inode = dip->inode;
6025         struct btrfs_root *root = BTRFS_I(inode)->root;
6026         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
6027         struct bio *bio;
6028         struct bio *orig_bio = dip->orig_bio;
6029         struct bio_vec *bvec = orig_bio->bi_io_vec;
6030         u64 start_sector = orig_bio->bi_sector;
6031         u64 file_offset = dip->logical_offset;
6032         u64 submit_len = 0;
6033         u64 map_length;
6034         int nr_pages = 0;
6035         u32 *csums = dip->csums;
6036         int ret = 0;
6037         int async_submit = 0;
6038         int write = rw & REQ_WRITE;
6039
6040         map_length = orig_bio->bi_size;
6041         ret = btrfs_map_block(map_tree, READ, start_sector << 9,
6042                               &map_length, NULL, 0);
6043         if (ret) {
6044                 bio_put(orig_bio);
6045                 return -EIO;
6046         }
6047
6048         if (map_length >= orig_bio->bi_size) {
6049                 bio = orig_bio;
6050                 goto submit;
6051         }
6052
6053         async_submit = 1;
6054         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev, start_sector, GFP_NOFS);
6055         if (!bio)
6056                 return -ENOMEM;
6057         bio->bi_private = dip;
6058         bio->bi_end_io = btrfs_end_dio_bio;
6059         atomic_inc(&dip->pending_bios);
6060
6061         while (bvec <= (orig_bio->bi_io_vec + orig_bio->bi_vcnt - 1)) {
6062                 if (unlikely(map_length < submit_len + bvec->bv_len ||
6063                     bio_add_page(bio, bvec->bv_page, bvec->bv_len,
6064                                  bvec->bv_offset) < bvec->bv_len)) {
6065                         /*
6066                          * inc the count before we submit the bio so
6067                          * we know the end IO handler won't happen before
6068                          * we inc the count. Otherwise, the dip might get freed
6069                          * before we're done setting it up
6070                          */
6071                         atomic_inc(&dip->pending_bios);
6072                         ret = __btrfs_submit_dio_bio(bio, inode, rw,
6073                                                      file_offset, skip_sum,
6074                                                      csums, async_submit);
6075                         if (ret) {
6076                                 bio_put(bio);
6077                                 atomic_dec(&dip->pending_bios);
6078                                 goto out_err;
6079                         }
6080
6081                         /* Write's use the ordered csums */
6082                         if (!write && !skip_sum)
6083                                 csums = csums + nr_pages;
6084                         start_sector += submit_len >> 9;
6085                         file_offset += submit_len;
6086
6087                         submit_len = 0;
6088                         nr_pages = 0;
6089
6090                         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev,
6091                                                   start_sector, GFP_NOFS);
6092                         if (!bio)
6093                                 goto out_err;
6094                         bio->bi_private = dip;
6095                         bio->bi_end_io = btrfs_end_dio_bio;
6096
6097                         map_length = orig_bio->bi_size;
6098                         ret = btrfs_map_block(map_tree, READ, start_sector << 9,
6099                                               &map_length, NULL, 0);
6100                         if (ret) {
6101                                 bio_put(bio);
6102                                 goto out_err;
6103                         }
6104                 } else {
6105                         submit_len += bvec->bv_len;
6106                         nr_pages ++;
6107                         bvec++;
6108                 }
6109         }
6110
6111 submit:
6112         ret = __btrfs_submit_dio_bio(bio, inode, rw, file_offset, skip_sum,
6113                                      csums, async_submit);
6114         if (!ret)
6115                 return 0;
6116
6117         bio_put(bio);
6118 out_err:
6119         dip->errors = 1;
6120         /*
6121          * before atomic variable goto zero, we must
6122          * make sure dip->errors is perceived to be set.
6123          */
6124         smp_mb__before_atomic_dec();
6125         if (atomic_dec_and_test(&dip->pending_bios))
6126                 bio_io_error(dip->orig_bio);
6127
6128         /* bio_end_io() will handle error, so we needn't return it */
6129         return 0;
6130 }
6131
6132 static void btrfs_submit_direct(int rw, struct bio *bio, struct inode *inode,
6133                                 loff_t file_offset)
6134 {
6135         struct btrfs_root *root = BTRFS_I(inode)->root;
6136         struct btrfs_dio_private *dip;
6137         struct bio_vec *bvec = bio->bi_io_vec;
6138         int skip_sum;
6139         int write = rw & REQ_WRITE;
6140         int ret = 0;
6141
6142         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
6143
6144         dip = kmalloc(sizeof(*dip), GFP_NOFS);
6145         if (!dip) {
6146                 ret = -ENOMEM;
6147                 goto free_ordered;
6148         }
6149         dip->csums = NULL;
6150
6151         /* Write's use the ordered csum stuff, so we don't need dip->csums */
6152         if (!write && !skip_sum) {
6153                 dip->csums = kmalloc(sizeof(u32) * bio->bi_vcnt, GFP_NOFS);
6154                 if (!dip->csums) {
6155                         kfree(dip);
6156                         ret = -ENOMEM;
6157                         goto free_ordered;
6158                 }
6159         }
6160
6161         dip->private = bio->bi_private;
6162         dip->inode = inode;
6163         dip->logical_offset = file_offset;
6164
6165         dip->bytes = 0;
6166         do {
6167                 dip->bytes += bvec->bv_len;
6168                 bvec++;
6169         } while (bvec <= (bio->bi_io_vec + bio->bi_vcnt - 1));
6170
6171         dip->disk_bytenr = (u64)bio->bi_sector << 9;
6172         bio->bi_private = dip;
6173         dip->errors = 0;
6174         dip->orig_bio = bio;
6175         atomic_set(&dip->pending_bios, 0);
6176
6177         if (write)
6178                 bio->bi_end_io = btrfs_endio_direct_write;
6179         else
6180                 bio->bi_end_io = btrfs_endio_direct_read;
6181
6182         ret = btrfs_submit_direct_hook(rw, dip, skip_sum);
6183         if (!ret)
6184                 return;
6185 free_ordered:
6186         /*
6187          * If this is a write, we need to clean up the reserved space and kill
6188          * the ordered extent.
6189          */
6190         if (write) {
6191                 struct btrfs_ordered_extent *ordered;
6192                 ordered = btrfs_lookup_ordered_extent(inode, file_offset);
6193                 if (!test_bit(BTRFS_ORDERED_PREALLOC, &ordered->flags) &&
6194                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered->flags))
6195                         btrfs_free_reserved_extent(root, ordered->start,
6196                                                    ordered->disk_len);
6197                 btrfs_put_ordered_extent(ordered);
6198                 btrfs_put_ordered_extent(ordered);
6199         }
6200         bio_endio(bio, ret);
6201 }
6202
6203 static ssize_t check_direct_IO(struct btrfs_root *root, int rw, struct kiocb *iocb,
6204                         const struct iovec *iov, loff_t offset,
6205                         unsigned long nr_segs)
6206 {
6207         int seg;
6208         int i;
6209         size_t size;
6210         unsigned long addr;
6211         unsigned blocksize_mask = root->sectorsize - 1;
6212         ssize_t retval = -EINVAL;
6213         loff_t end = offset;
6214
6215         if (offset & blocksize_mask)
6216                 goto out;
6217
6218         /* Check the memory alignment.  Blocks cannot straddle pages */
6219         for (seg = 0; seg < nr_segs; seg++) {
6220                 addr = (unsigned long)iov[seg].iov_base;
6221                 size = iov[seg].iov_len;
6222                 end += size;
6223                 if ((addr & blocksize_mask) || (size & blocksize_mask))
6224                         goto out;
6225
6226                 /* If this is a write we don't need to check anymore */
6227                 if (rw & WRITE)
6228                         continue;
6229
6230                 /*
6231                  * Check to make sure we don't have duplicate iov_base's in this
6232                  * iovec, if so return EINVAL, otherwise we'll get csum errors
6233                  * when reading back.
6234                  */
6235                 for (i = seg + 1; i < nr_segs; i++) {
6236                         if (iov[seg].iov_base == iov[i].iov_base)
6237                                 goto out;
6238                 }
6239         }
6240         retval = 0;
6241 out:
6242         return retval;
6243 }
6244 static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
6245                         const struct iovec *iov, loff_t offset,
6246                         unsigned long nr_segs)
6247 {
6248         struct file *file = iocb->ki_filp;
6249         struct inode *inode = file->f_mapping->host;
6250         struct btrfs_ordered_extent *ordered;
6251         struct extent_state *cached_state = NULL;
6252         u64 lockstart, lockend;
6253         ssize_t ret;
6254         int writing = rw & WRITE;
6255         int write_bits = 0;
6256         size_t count = iov_length(iov, nr_segs);
6257
6258         if (check_direct_IO(BTRFS_I(inode)->root, rw, iocb, iov,
6259                             offset, nr_segs)) {
6260                 return 0;
6261         }
6262
6263         lockstart = offset;
6264         lockend = offset + count - 1;
6265
6266         if (writing) {
6267                 ret = btrfs_delalloc_reserve_space(inode, count);
6268                 if (ret)
6269                         goto out;
6270         }
6271
6272         while (1) {
6273                 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
6274                                  0, &cached_state, GFP_NOFS);
6275                 /*
6276                  * We're concerned with the entire range that we're going to be
6277                  * doing DIO to, so we need to make sure theres no ordered
6278                  * extents in this range.
6279                  */
6280                 ordered = btrfs_lookup_ordered_range(inode, lockstart,
6281                                                      lockend - lockstart + 1);
6282                 if (!ordered)
6283                         break;
6284                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
6285                                      &cached_state, GFP_NOFS);
6286                 btrfs_start_ordered_extent(inode, ordered, 1);
6287                 btrfs_put_ordered_extent(ordered);
6288                 cond_resched();
6289         }
6290
6291         /*
6292          * we don't use btrfs_set_extent_delalloc because we don't want
6293          * the dirty or uptodate bits
6294          */
6295         if (writing) {
6296                 write_bits = EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING;
6297                 ret = set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
6298                                      EXTENT_DELALLOC, 0, NULL, &cached_state,
6299                                      GFP_NOFS);
6300                 if (ret) {
6301                         clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
6302                                          lockend, EXTENT_LOCKED | write_bits,
6303                                          1, 0, &cached_state, GFP_NOFS);
6304                         goto out;
6305                 }
6306         }
6307
6308         free_extent_state(cached_state);
6309         cached_state = NULL;
6310
6311         ret = __blockdev_direct_IO(rw, iocb, inode,
6312                    BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev,
6313                    iov, offset, nr_segs, btrfs_get_blocks_direct, NULL,
6314                    btrfs_submit_direct, 0);
6315
6316         if (ret < 0 && ret != -EIOCBQUEUED) {
6317                 clear_extent_bit(&BTRFS_I(inode)->io_tree, offset,
6318                               offset + iov_length(iov, nr_segs) - 1,
6319                               EXTENT_LOCKED | write_bits, 1, 0,
6320                               &cached_state, GFP_NOFS);
6321         } else if (ret >= 0 && ret < iov_length(iov, nr_segs)) {
6322                 /*
6323                  * We're falling back to buffered, unlock the section we didn't
6324                  * do IO on.
6325                  */
6326                 clear_extent_bit(&BTRFS_I(inode)->io_tree, offset + ret,
6327                               offset + iov_length(iov, nr_segs) - 1,
6328                               EXTENT_LOCKED | write_bits, 1, 0,
6329                               &cached_state, GFP_NOFS);
6330         }
6331 out:
6332         free_extent_state(cached_state);
6333         return ret;
6334 }
6335
6336 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
6337                 __u64 start, __u64 len)
6338 {
6339         return extent_fiemap(inode, fieinfo, start, len, btrfs_get_extent_fiemap);
6340 }
6341
6342 int btrfs_readpage(struct file *file, struct page *page)
6343 {
6344         struct extent_io_tree *tree;
6345         tree = &BTRFS_I(page->mapping->host)->io_tree;
6346         return extent_read_full_page(tree, page, btrfs_get_extent);
6347 }
6348
6349 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
6350 {
6351         struct extent_io_tree *tree;
6352
6353
6354         if (current->flags & PF_MEMALLOC) {
6355                 redirty_page_for_writepage(wbc, page);
6356                 unlock_page(page);
6357                 return 0;
6358         }
6359         tree = &BTRFS_I(page->mapping->host)->io_tree;
6360         return extent_write_full_page(tree, page, btrfs_get_extent, wbc);
6361 }
6362
6363 int btrfs_writepages(struct address_space *mapping,
6364                      struct writeback_control *wbc)
6365 {
6366         struct extent_io_tree *tree;
6367
6368         tree = &BTRFS_I(mapping->host)->io_tree;
6369         return extent_writepages(tree, mapping, btrfs_get_extent, wbc);
6370 }
6371
6372 static int
6373 btrfs_readpages(struct file *file, struct address_space *mapping,
6374                 struct list_head *pages, unsigned nr_pages)
6375 {
6376         struct extent_io_tree *tree;
6377         tree = &BTRFS_I(mapping->host)->io_tree;
6378         return extent_readpages(tree, mapping, pages, nr_pages,
6379                                 btrfs_get_extent);
6380 }
6381 static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
6382 {
6383         struct extent_io_tree *tree;
6384         struct extent_map_tree *map;
6385         int ret;
6386
6387         tree = &BTRFS_I(page->mapping->host)->io_tree;
6388         map = &BTRFS_I(page->mapping->host)->extent_tree;
6389         ret = try_release_extent_mapping(map, tree, page, gfp_flags);
6390         if (ret == 1) {
6391                 ClearPagePrivate(page);
6392                 set_page_private(page, 0);
6393                 page_cache_release(page);
6394         }
6395         return ret;
6396 }
6397
6398 static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
6399 {
6400         if (PageWriteback(page) || PageDirty(page))
6401                 return 0;
6402         return __btrfs_releasepage(page, gfp_flags & GFP_NOFS);
6403 }
6404
6405 static void btrfs_invalidatepage(struct page *page, unsigned long offset)
6406 {
6407         struct extent_io_tree *tree;
6408         struct btrfs_ordered_extent *ordered;
6409         struct extent_state *cached_state = NULL;
6410         u64 page_start = page_offset(page);
6411         u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
6412
6413
6414         /*
6415          * we have the page locked, so new writeback can't start,
6416          * and the dirty bit won't be cleared while we are here.
6417          *
6418          * Wait for IO on this page so that we can safely clear
6419          * the PagePrivate2 bit and do ordered accounting
6420          */
6421         wait_on_page_writeback(page);
6422
6423         tree = &BTRFS_I(page->mapping->host)->io_tree;
6424         if (offset) {
6425                 btrfs_releasepage(page, GFP_NOFS);
6426                 return;
6427         }
6428         lock_extent_bits(tree, page_start, page_end, 0, &cached_state,
6429                          GFP_NOFS);
6430         ordered = btrfs_lookup_ordered_extent(page->mapping->host,
6431                                            page_offset(page));
6432         if (ordered) {
6433                 /*
6434                  * IO on this page will never be started, so we need
6435                  * to account for any ordered extents now
6436                  */
6437                 clear_extent_bit(tree, page_start, page_end,
6438                                  EXTENT_DIRTY | EXTENT_DELALLOC |
6439                                  EXTENT_LOCKED | EXTENT_DO_ACCOUNTING, 1, 0,
6440                                  &cached_state, GFP_NOFS);
6441                 /*
6442                  * whoever cleared the private bit is responsible
6443                  * for the finish_ordered_io
6444                  */
6445                 if (TestClearPagePrivate2(page)) {
6446                         btrfs_finish_ordered_io(page->mapping->host,
6447                                                 page_start, page_end);
6448                 }
6449                 btrfs_put_ordered_extent(ordered);
6450                 cached_state = NULL;
6451                 lock_extent_bits(tree, page_start, page_end, 0, &cached_state,
6452                                  GFP_NOFS);
6453         }
6454         clear_extent_bit(tree, page_start, page_end,
6455                  EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
6456                  EXTENT_DO_ACCOUNTING, 1, 1, &cached_state, GFP_NOFS);
6457         __btrfs_releasepage(page, GFP_NOFS);
6458
6459         ClearPageChecked(page);
6460         if (PagePrivate(page)) {
6461                 ClearPagePrivate(page);
6462                 set_page_private(page, 0);
6463                 page_cache_release(page);
6464         }
6465 }
6466
6467 /*
6468  * btrfs_page_mkwrite() is not allowed to change the file size as it gets
6469  * called from a page fault handler when a page is first dirtied. Hence we must
6470  * be careful to check for EOF conditions here. We set the page up correctly
6471  * for a written page which means we get ENOSPC checking when writing into
6472  * holes and correct delalloc and unwritten extent mapping on filesystems that
6473  * support these features.
6474  *
6475  * We are not allowed to take the i_mutex here so we have to play games to
6476  * protect against truncate races as the page could now be beyond EOF.  Because
6477  * vmtruncate() writes the inode size before removing pages, once we have the
6478  * page lock we can determine safely if the page is beyond EOF. If it is not
6479  * beyond EOF, then the page is guaranteed safe against truncation until we
6480  * unlock the page.
6481  */
6482 int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
6483 {
6484         struct page *page = vmf->page;
6485         struct inode *inode = fdentry(vma->vm_file)->d_inode;
6486         struct btrfs_root *root = BTRFS_I(inode)->root;
6487         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6488         struct btrfs_ordered_extent *ordered;
6489         struct extent_state *cached_state = NULL;
6490         char *kaddr;
6491         unsigned long zero_start;
6492         loff_t size;
6493         int ret;
6494         u64 page_start;
6495         u64 page_end;
6496
6497         ret  = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
6498         if (ret) {
6499                 if (ret == -ENOMEM)
6500                         ret = VM_FAULT_OOM;
6501                 else /* -ENOSPC, -EIO, etc */
6502                         ret = VM_FAULT_SIGBUS;
6503                 goto out;
6504         }
6505
6506         ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
6507 again:
6508         lock_page(page);
6509         size = i_size_read(inode);
6510         page_start = page_offset(page);
6511         page_end = page_start + PAGE_CACHE_SIZE - 1;
6512
6513         if ((page->mapping != inode->i_mapping) ||
6514             (page_start >= size)) {
6515                 /* page got truncated out from underneath us */
6516                 goto out_unlock;
6517         }
6518         wait_on_page_writeback(page);
6519
6520         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state,
6521                          GFP_NOFS);
6522         set_page_extent_mapped(page);
6523
6524         /*
6525          * we can't set the delalloc bits if there are pending ordered
6526          * extents.  Drop our locks and wait for them to finish
6527          */
6528         ordered = btrfs_lookup_ordered_extent(inode, page_start);
6529         if (ordered) {
6530                 unlock_extent_cached(io_tree, page_start, page_end,
6531                                      &cached_state, GFP_NOFS);
6532                 unlock_page(page);
6533                 btrfs_start_ordered_extent(inode, ordered, 1);
6534                 btrfs_put_ordered_extent(ordered);
6535                 goto again;
6536         }
6537
6538         /*
6539          * XXX - page_mkwrite gets called every time the page is dirtied, even
6540          * if it was already dirty, so for space accounting reasons we need to
6541          * clear any delalloc bits for the range we are fixing to save.  There
6542          * is probably a better way to do this, but for now keep consistent with
6543          * prepare_pages in the normal write path.
6544          */
6545         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
6546                           EXTENT_DIRTY | EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING,
6547                           0, 0, &cached_state, GFP_NOFS);
6548
6549         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
6550                                         &cached_state);
6551         if (ret) {
6552                 unlock_extent_cached(io_tree, page_start, page_end,
6553                                      &cached_state, GFP_NOFS);
6554                 ret = VM_FAULT_SIGBUS;
6555                 goto out_unlock;
6556         }
6557         ret = 0;
6558
6559         /* page is wholly or partially inside EOF */
6560         if (page_start + PAGE_CACHE_SIZE > size)
6561                 zero_start = size & ~PAGE_CACHE_MASK;
6562         else
6563                 zero_start = PAGE_CACHE_SIZE;
6564
6565         if (zero_start != PAGE_CACHE_SIZE) {
6566                 kaddr = kmap(page);
6567                 memset(kaddr + zero_start, 0, PAGE_CACHE_SIZE - zero_start);
6568                 flush_dcache_page(page);
6569                 kunmap(page);
6570         }
6571         ClearPageChecked(page);
6572         set_page_dirty(page);
6573         SetPageUptodate(page);
6574
6575         BTRFS_I(inode)->last_trans = root->fs_info->generation;
6576         BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
6577
6578         unlock_extent_cached(io_tree, page_start, page_end, &cached_state, GFP_NOFS);
6579
6580 out_unlock:
6581         if (!ret)
6582                 return VM_FAULT_LOCKED;
6583         unlock_page(page);
6584         btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
6585 out:
6586         return ret;
6587 }
6588
6589 static int btrfs_truncate(struct inode *inode)
6590 {
6591         struct btrfs_root *root = BTRFS_I(inode)->root;
6592         int ret;
6593         int err = 0;
6594         struct btrfs_trans_handle *trans;
6595         unsigned long nr;
6596         u64 mask = root->sectorsize - 1;
6597
6598         ret = btrfs_truncate_page(inode->i_mapping, inode->i_size);
6599         if (ret)
6600                 return ret;
6601
6602         btrfs_wait_ordered_range(inode, inode->i_size & (~mask), (u64)-1);
6603         btrfs_ordered_update_i_size(inode, inode->i_size, NULL);
6604
6605         trans = btrfs_start_transaction(root, 5);
6606         if (IS_ERR(trans))
6607                 return PTR_ERR(trans);
6608
6609         btrfs_set_trans_block_group(trans, inode);
6610
6611         ret = btrfs_orphan_add(trans, inode);
6612         if (ret) {
6613                 btrfs_end_transaction(trans, root);
6614                 return ret;
6615         }
6616
6617         nr = trans->blocks_used;
6618         btrfs_end_transaction(trans, root);
6619         btrfs_btree_balance_dirty(root, nr);
6620
6621         /* Now start a transaction for the truncate */
6622         trans = btrfs_start_transaction(root, 0);
6623         if (IS_ERR(trans))
6624                 return PTR_ERR(trans);
6625         btrfs_set_trans_block_group(trans, inode);
6626         trans->block_rsv = root->orphan_block_rsv;
6627
6628         /*
6629          * setattr is responsible for setting the ordered_data_close flag,
6630          * but that is only tested during the last file release.  That
6631          * could happen well after the next commit, leaving a great big
6632          * window where new writes may get lost if someone chooses to write
6633          * to this file after truncating to zero
6634          *
6635          * The inode doesn't have any dirty data here, and so if we commit
6636          * this is a noop.  If someone immediately starts writing to the inode
6637          * it is very likely we'll catch some of their writes in this
6638          * transaction, and the commit will find this file on the ordered
6639          * data list with good things to send down.
6640          *
6641          * This is a best effort solution, there is still a window where
6642          * using truncate to replace the contents of the file will
6643          * end up with a zero length file after a crash.
6644          */
6645         if (inode->i_size == 0 && BTRFS_I(inode)->ordered_data_close)
6646                 btrfs_add_ordered_operation(trans, root, inode);
6647
6648         while (1) {
6649                 if (!trans) {
6650                         trans = btrfs_start_transaction(root, 0);
6651                         if (IS_ERR(trans))
6652                                 return PTR_ERR(trans);
6653                         btrfs_set_trans_block_group(trans, inode);
6654                         trans->block_rsv = root->orphan_block_rsv;
6655                 }
6656
6657                 ret = btrfs_block_rsv_check(trans, root,
6658                                             root->orphan_block_rsv, 0, 5);
6659                 if (ret == -EAGAIN) {
6660                         ret = btrfs_commit_transaction(trans, root);
6661                         if (ret)
6662                                 return ret;
6663                         trans = NULL;
6664                         continue;
6665                 } else if (ret) {
6666                         err = ret;
6667                         break;
6668                 }
6669
6670                 ret = btrfs_truncate_inode_items(trans, root, inode,
6671                                                  inode->i_size,
6672                                                  BTRFS_EXTENT_DATA_KEY);
6673                 if (ret != -EAGAIN) {
6674                         err = ret;
6675                         break;
6676                 }
6677
6678                 ret = btrfs_update_inode(trans, root, inode);
6679                 if (ret) {
6680                         err = ret;
6681                         break;
6682                 }
6683
6684                 nr = trans->blocks_used;
6685                 btrfs_end_transaction(trans, root);
6686                 trans = NULL;
6687                 btrfs_btree_balance_dirty(root, nr);
6688         }
6689
6690         if (ret == 0 && inode->i_nlink > 0) {
6691                 ret = btrfs_orphan_del(trans, inode);
6692                 if (ret)
6693                         err = ret;
6694         } else if (ret && inode->i_nlink > 0) {
6695                 /*
6696                  * Failed to do the truncate, remove us from the in memory
6697                  * orphan list.
6698                  */
6699                 ret = btrfs_orphan_del(NULL, inode);
6700         }
6701
6702         ret = btrfs_update_inode(trans, root, inode);
6703         if (ret && !err)
6704                 err = ret;
6705
6706         nr = trans->blocks_used;
6707         ret = btrfs_end_transaction_throttle(trans, root);
6708         if (ret && !err)
6709                 err = ret;
6710         btrfs_btree_balance_dirty(root, nr);
6711
6712         return err;
6713 }
6714
6715 /*
6716  * create a new subvolume directory/inode (helper for the ioctl).
6717  */
6718 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
6719                              struct btrfs_root *new_root,
6720                              u64 new_dirid, u64 alloc_hint)
6721 {
6722         struct inode *inode;
6723         int err;
6724         u64 index = 0;
6725
6726         inode = btrfs_new_inode(trans, new_root, NULL, "..", 2, new_dirid,
6727                                 new_dirid, alloc_hint, S_IFDIR | 0700, &index);
6728         if (IS_ERR(inode))
6729                 return PTR_ERR(inode);
6730         inode->i_op = &btrfs_dir_inode_operations;
6731         inode->i_fop = &btrfs_dir_file_operations;
6732
6733         inode->i_nlink = 1;
6734         btrfs_i_size_write(inode, 0);
6735
6736         err = btrfs_update_inode(trans, new_root, inode);
6737         BUG_ON(err);
6738
6739         iput(inode);
6740         return 0;
6741 }
6742
6743 /* helper function for file defrag and space balancing.  This
6744  * forces readahead on a given range of bytes in an inode
6745  */
6746 unsigned long btrfs_force_ra(struct address_space *mapping,
6747                               struct file_ra_state *ra, struct file *file,
6748                               pgoff_t offset, pgoff_t last_index)
6749 {
6750         pgoff_t req_size = last_index - offset + 1;
6751
6752         page_cache_sync_readahead(mapping, ra, file, offset, req_size);
6753         return offset + req_size;
6754 }
6755
6756 struct inode *btrfs_alloc_inode(struct super_block *sb)
6757 {
6758         struct btrfs_inode *ei;
6759         struct inode *inode;
6760
6761         ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_NOFS);
6762         if (!ei)
6763                 return NULL;
6764
6765         ei->root = NULL;
6766         ei->space_info = NULL;
6767         ei->generation = 0;
6768         ei->sequence = 0;
6769         ei->last_trans = 0;
6770         ei->last_sub_trans = 0;
6771         ei->logged_trans = 0;
6772         ei->delalloc_bytes = 0;
6773         ei->reserved_bytes = 0;
6774         ei->disk_i_size = 0;
6775         ei->flags = 0;
6776         ei->index_cnt = (u64)-1;
6777         ei->last_unlink_trans = 0;
6778
6779         atomic_set(&ei->outstanding_extents, 0);
6780         atomic_set(&ei->reserved_extents, 0);
6781
6782         ei->ordered_data_close = 0;
6783         ei->orphan_meta_reserved = 0;
6784         ei->dummy_inode = 0;
6785         ei->force_compress = BTRFS_COMPRESS_NONE;
6786
6787         inode = &ei->vfs_inode;
6788         extent_map_tree_init(&ei->extent_tree, GFP_NOFS);
6789         extent_io_tree_init(&ei->io_tree, &inode->i_data, GFP_NOFS);
6790         extent_io_tree_init(&ei->io_failure_tree, &inode->i_data, GFP_NOFS);
6791         mutex_init(&ei->log_mutex);
6792         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
6793         INIT_LIST_HEAD(&ei->i_orphan);
6794         INIT_LIST_HEAD(&ei->delalloc_inodes);
6795         INIT_LIST_HEAD(&ei->ordered_operations);
6796         RB_CLEAR_NODE(&ei->rb_node);
6797
6798         return inode;
6799 }
6800
6801 static void btrfs_i_callback(struct rcu_head *head)
6802 {
6803         struct inode *inode = container_of(head, struct inode, i_rcu);
6804         INIT_LIST_HEAD(&inode->i_dentry);
6805         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
6806 }
6807
6808 void btrfs_destroy_inode(struct inode *inode)
6809 {
6810         struct btrfs_ordered_extent *ordered;
6811         struct btrfs_root *root = BTRFS_I(inode)->root;
6812
6813         WARN_ON(!list_empty(&inode->i_dentry));
6814         WARN_ON(inode->i_data.nrpages);
6815         WARN_ON(atomic_read(&BTRFS_I(inode)->outstanding_extents));
6816         WARN_ON(atomic_read(&BTRFS_I(inode)->reserved_extents));
6817
6818         /*
6819          * This can happen where we create an inode, but somebody else also
6820          * created the same inode and we need to destroy the one we already
6821          * created.
6822          */
6823         if (!root)
6824                 goto free;
6825
6826         /*
6827          * Make sure we're properly removed from the ordered operation
6828          * lists.
6829          */
6830         smp_mb();
6831         if (!list_empty(&BTRFS_I(inode)->ordered_operations)) {
6832                 spin_lock(&root->fs_info->ordered_extent_lock);
6833                 list_del_init(&BTRFS_I(inode)->ordered_operations);
6834                 spin_unlock(&root->fs_info->ordered_extent_lock);
6835         }
6836
6837         if (root == root->fs_info->tree_root) {
6838                 struct btrfs_block_group_cache *block_group;
6839
6840                 block_group = btrfs_lookup_block_group(root->fs_info,
6841                                                 BTRFS_I(inode)->block_group);
6842                 if (block_group && block_group->inode == inode) {
6843                         spin_lock(&block_group->lock);
6844                         block_group->inode = NULL;
6845                         spin_unlock(&block_group->lock);
6846                         btrfs_put_block_group(block_group);
6847                 } else if (block_group) {
6848                         btrfs_put_block_group(block_group);
6849                 }
6850         }
6851
6852         spin_lock(&root->orphan_lock);
6853         if (!list_empty(&BTRFS_I(inode)->i_orphan)) {
6854                 printk(KERN_INFO "BTRFS: inode %lu still on the orphan list\n",
6855                        inode->i_ino);
6856                 list_del_init(&BTRFS_I(inode)->i_orphan);
6857         }
6858         spin_unlock(&root->orphan_lock);
6859
6860         while (1) {
6861                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
6862                 if (!ordered)
6863                         break;
6864                 else {
6865                         printk(KERN_ERR "btrfs found ordered "
6866                                "extent %llu %llu on inode cleanup\n",
6867                                (unsigned long long)ordered->file_offset,
6868                                (unsigned long long)ordered->len);
6869                         btrfs_remove_ordered_extent(inode, ordered);
6870                         btrfs_put_ordered_extent(ordered);
6871                         btrfs_put_ordered_extent(ordered);
6872                 }
6873         }
6874         inode_tree_del(inode);
6875         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
6876 free:
6877         call_rcu(&inode->i_rcu, btrfs_i_callback);
6878 }
6879
6880 int btrfs_drop_inode(struct inode *inode)
6881 {
6882         struct btrfs_root *root = BTRFS_I(inode)->root;
6883
6884         if (btrfs_root_refs(&root->root_item) == 0 &&
6885             root != root->fs_info->tree_root)
6886                 return 1;
6887         else
6888                 return generic_drop_inode(inode);
6889 }
6890
6891 static void init_once(void *foo)
6892 {
6893         struct btrfs_inode *ei = (struct btrfs_inode *) foo;
6894
6895         inode_init_once(&ei->vfs_inode);
6896 }
6897
6898 void btrfs_destroy_cachep(void)
6899 {
6900         if (btrfs_inode_cachep)
6901                 kmem_cache_destroy(btrfs_inode_cachep);
6902         if (btrfs_trans_handle_cachep)
6903                 kmem_cache_destroy(btrfs_trans_handle_cachep);
6904         if (btrfs_transaction_cachep)
6905                 kmem_cache_destroy(btrfs_transaction_cachep);
6906         if (btrfs_path_cachep)
6907                 kmem_cache_destroy(btrfs_path_cachep);
6908         if (btrfs_free_space_cachep)
6909                 kmem_cache_destroy(btrfs_free_space_cachep);
6910 }
6911
6912 int btrfs_init_cachep(void)
6913 {
6914         btrfs_inode_cachep = kmem_cache_create("btrfs_inode_cache",
6915                         sizeof(struct btrfs_inode), 0,
6916                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, init_once);
6917         if (!btrfs_inode_cachep)
6918                 goto fail;
6919
6920         btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle_cache",
6921                         sizeof(struct btrfs_trans_handle), 0,
6922                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
6923         if (!btrfs_trans_handle_cachep)
6924                 goto fail;
6925
6926         btrfs_transaction_cachep = kmem_cache_create("btrfs_transaction_cache",
6927                         sizeof(struct btrfs_transaction), 0,
6928                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
6929         if (!btrfs_transaction_cachep)
6930                 goto fail;
6931
6932         btrfs_path_cachep = kmem_cache_create("btrfs_path_cache",
6933                         sizeof(struct btrfs_path), 0,
6934                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
6935         if (!btrfs_path_cachep)
6936                 goto fail;
6937
6938         btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space_cache",
6939                         sizeof(struct btrfs_free_space), 0,
6940                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
6941         if (!btrfs_free_space_cachep)
6942                 goto fail;
6943
6944         return 0;
6945 fail:
6946         btrfs_destroy_cachep();
6947         return -ENOMEM;
6948 }
6949
6950 static int btrfs_getattr(struct vfsmount *mnt,
6951                          struct dentry *dentry, struct kstat *stat)
6952 {
6953         struct inode *inode = dentry->d_inode;
6954         generic_fillattr(inode, stat);
6955         stat->dev = BTRFS_I(inode)->root->anon_super.s_dev;
6956         stat->blksize = PAGE_CACHE_SIZE;
6957         stat->blocks = (inode_get_bytes(inode) +
6958                         BTRFS_I(inode)->delalloc_bytes) >> 9;
6959         return 0;
6960 }
6961
6962 /*
6963  * If a file is moved, it will inherit the cow and compression flags of the new
6964  * directory.
6965  */
6966 static void fixup_inode_flags(struct inode *dir, struct inode *inode)
6967 {
6968         struct btrfs_inode *b_dir = BTRFS_I(dir);
6969         struct btrfs_inode *b_inode = BTRFS_I(inode);
6970
6971         if (b_dir->flags & BTRFS_INODE_NODATACOW)
6972                 b_inode->flags |= BTRFS_INODE_NODATACOW;
6973         else
6974                 b_inode->flags &= ~BTRFS_INODE_NODATACOW;
6975
6976         if (b_dir->flags & BTRFS_INODE_COMPRESS)
6977                 b_inode->flags |= BTRFS_INODE_COMPRESS;
6978         else
6979                 b_inode->flags &= ~BTRFS_INODE_COMPRESS;
6980 }
6981
6982 static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
6983                            struct inode *new_dir, struct dentry *new_dentry)
6984 {
6985         struct btrfs_trans_handle *trans;
6986         struct btrfs_root *root = BTRFS_I(old_dir)->root;
6987         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
6988         struct inode *new_inode = new_dentry->d_inode;
6989         struct inode *old_inode = old_dentry->d_inode;
6990         struct timespec ctime = CURRENT_TIME;
6991         u64 index = 0;
6992         u64 root_objectid;
6993         int ret;
6994
6995         if (new_dir->i_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
6996                 return -EPERM;
6997
6998         /* we only allow rename subvolume link between subvolumes */
6999         if (old_inode->i_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
7000                 return -EXDEV;
7001
7002         if (old_inode->i_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID ||
7003             (new_inode && new_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID))
7004                 return -ENOTEMPTY;
7005
7006         if (S_ISDIR(old_inode->i_mode) && new_inode &&
7007             new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
7008                 return -ENOTEMPTY;
7009         /*
7010          * we're using rename to replace one file with another.
7011          * and the replacement file is large.  Start IO on it now so
7012          * we don't add too much work to the end of the transaction
7013          */
7014         if (new_inode && S_ISREG(old_inode->i_mode) && new_inode->i_size &&
7015             old_inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
7016                 filemap_flush(old_inode->i_mapping);
7017
7018         /* close the racy window with snapshot create/destroy ioctl */
7019         if (old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
7020                 down_read(&root->fs_info->subvol_sem);
7021         /*
7022          * We want to reserve the absolute worst case amount of items.  So if
7023          * both inodes are subvols and we need to unlink them then that would
7024          * require 4 item modifications, but if they are both normal inodes it
7025          * would require 5 item modifications, so we'll assume their normal
7026          * inodes.  So 5 * 2 is 10, plus 1 for the new link, so 11 total items
7027          * should cover the worst case number of items we'll modify.
7028          */
7029         trans = btrfs_start_transaction(root, 20);
7030         if (IS_ERR(trans)) {
7031                 ret = PTR_ERR(trans);
7032                 goto out_notrans;
7033         }
7034
7035         btrfs_set_trans_block_group(trans, new_dir);
7036
7037         if (dest != root)
7038                 btrfs_record_root_in_trans(trans, dest);
7039
7040         ret = btrfs_set_inode_index(new_dir, &index);
7041         if (ret)
7042                 goto out_fail;
7043
7044         if (unlikely(old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)) {
7045                 /* force full log commit if subvolume involved. */
7046                 root->fs_info->last_trans_log_full_commit = trans->transid;
7047         } else {
7048                 ret = btrfs_insert_inode_ref(trans, dest,
7049                                              new_dentry->d_name.name,
7050                                              new_dentry->d_name.len,
7051                                              old_inode->i_ino,
7052                                              new_dir->i_ino, index);
7053                 if (ret)
7054                         goto out_fail;
7055                 /*
7056                  * this is an ugly little race, but the rename is required
7057                  * to make sure that if we crash, the inode is either at the
7058                  * old name or the new one.  pinning the log transaction lets
7059                  * us make sure we don't allow a log commit to come in after
7060                  * we unlink the name but before we add the new name back in.
7061                  */
7062                 btrfs_pin_log_trans(root);
7063         }
7064         /*
7065          * make sure the inode gets flushed if it is replacing
7066          * something.
7067          */
7068         if (new_inode && new_inode->i_size &&
7069             old_inode && S_ISREG(old_inode->i_mode)) {
7070                 btrfs_add_ordered_operation(trans, root, old_inode);
7071         }
7072
7073         old_dir->i_ctime = old_dir->i_mtime = ctime;
7074         new_dir->i_ctime = new_dir->i_mtime = ctime;
7075         old_inode->i_ctime = ctime;
7076
7077         if (old_dentry->d_parent != new_dentry->d_parent)
7078                 btrfs_record_unlink_dir(trans, old_dir, old_inode, 1);
7079
7080         if (unlikely(old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)) {
7081                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
7082                 ret = btrfs_unlink_subvol(trans, root, old_dir, root_objectid,
7083                                         old_dentry->d_name.name,
7084                                         old_dentry->d_name.len);
7085         } else {
7086                 ret = __btrfs_unlink_inode(trans, root, old_dir,
7087                                         old_dentry->d_inode,
7088                                         old_dentry->d_name.name,
7089                                         old_dentry->d_name.len);
7090                 if (!ret)
7091                         ret = btrfs_update_inode(trans, root, old_inode);
7092         }
7093         BUG_ON(ret);
7094
7095         if (new_inode) {
7096                 new_inode->i_ctime = CURRENT_TIME;
7097                 if (unlikely(new_inode->i_ino ==
7098                              BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
7099                         root_objectid = BTRFS_I(new_inode)->location.objectid;
7100                         ret = btrfs_unlink_subvol(trans, dest, new_dir,
7101                                                 root_objectid,
7102                                                 new_dentry->d_name.name,
7103                                                 new_dentry->d_name.len);
7104                         BUG_ON(new_inode->i_nlink == 0);
7105                 } else {
7106                         ret = btrfs_unlink_inode(trans, dest, new_dir,
7107                                                  new_dentry->d_inode,
7108                                                  new_dentry->d_name.name,
7109                                                  new_dentry->d_name.len);
7110                 }
7111                 BUG_ON(ret);
7112                 if (new_inode->i_nlink == 0) {
7113                         ret = btrfs_orphan_add(trans, new_dentry->d_inode);
7114                         BUG_ON(ret);
7115                 }
7116         }
7117
7118         fixup_inode_flags(new_dir, old_inode);
7119
7120         ret = btrfs_add_link(trans, new_dir, old_inode,
7121                              new_dentry->d_name.name,
7122                              new_dentry->d_name.len, 0, index);
7123         BUG_ON(ret);
7124
7125         if (old_inode->i_ino != BTRFS_FIRST_FREE_OBJECTID) {
7126                 struct dentry *parent = dget_parent(new_dentry);
7127                 btrfs_log_new_name(trans, old_inode, old_dir, parent);
7128                 dput(parent);
7129                 btrfs_end_log_trans(root);
7130         }
7131 out_fail:
7132         btrfs_end_transaction_throttle(trans, root);
7133 out_notrans:
7134         if (old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
7135                 up_read(&root->fs_info->subvol_sem);
7136
7137         return ret;
7138 }
7139
7140 /*
7141  * some fairly slow code that needs optimization. This walks the list
7142  * of all the inodes with pending delalloc and forces them to disk.
7143  */
7144 int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
7145 {
7146         struct list_head *head = &root->fs_info->delalloc_inodes;
7147         struct btrfs_inode *binode;
7148         struct inode *inode;
7149
7150         if (root->fs_info->sb->s_flags & MS_RDONLY)
7151                 return -EROFS;
7152
7153         spin_lock(&root->fs_info->delalloc_lock);
7154         while (!list_empty(head)) {
7155                 binode = list_entry(head->next, struct btrfs_inode,
7156                                     delalloc_inodes);
7157                 inode = igrab(&binode->vfs_inode);
7158                 if (!inode)
7159                         list_del_init(&binode->delalloc_inodes);
7160                 spin_unlock(&root->fs_info->delalloc_lock);
7161                 if (inode) {
7162                         filemap_flush(inode->i_mapping);
7163                         if (delay_iput)
7164                                 btrfs_add_delayed_iput(inode);
7165                         else
7166                                 iput(inode);
7167                 }
7168                 cond_resched();
7169                 spin_lock(&root->fs_info->delalloc_lock);
7170         }
7171         spin_unlock(&root->fs_info->delalloc_lock);
7172
7173         /* the filemap_flush will queue IO into the worker threads, but
7174          * we have to make sure the IO is actually started and that
7175          * ordered extents get created before we return
7176          */
7177         atomic_inc(&root->fs_info->async_submit_draining);
7178         while (atomic_read(&root->fs_info->nr_async_submits) ||
7179               atomic_read(&root->fs_info->async_delalloc_pages)) {
7180                 wait_event(root->fs_info->async_submit_wait,
7181                    (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
7182                     atomic_read(&root->fs_info->async_delalloc_pages) == 0));
7183         }
7184         atomic_dec(&root->fs_info->async_submit_draining);
7185         return 0;
7186 }
7187
7188 int btrfs_start_one_delalloc_inode(struct btrfs_root *root, int delay_iput,
7189                                    int sync)
7190 {
7191         struct btrfs_inode *binode;
7192         struct inode *inode = NULL;
7193
7194         spin_lock(&root->fs_info->delalloc_lock);
7195         while (!list_empty(&root->fs_info->delalloc_inodes)) {
7196                 binode = list_entry(root->fs_info->delalloc_inodes.next,
7197                                     struct btrfs_inode, delalloc_inodes);
7198                 inode = igrab(&binode->vfs_inode);
7199                 if (inode) {
7200                         list_move_tail(&binode->delalloc_inodes,
7201                                        &root->fs_info->delalloc_inodes);
7202                         break;
7203                 }
7204
7205                 list_del_init(&binode->delalloc_inodes);
7206                 cond_resched_lock(&root->fs_info->delalloc_lock);
7207         }
7208         spin_unlock(&root->fs_info->delalloc_lock);
7209
7210         if (inode) {
7211                 if (sync) {
7212                         filemap_write_and_wait(inode->i_mapping);
7213                         /*
7214                          * We have to do this because compression doesn't
7215                          * actually set PG_writeback until it submits the pages
7216                          * for IO, which happens in an async thread, so we could
7217                          * race and not actually wait for any writeback pages
7218                          * because they've not been submitted yet.  Technically
7219                          * this could still be the case for the ordered stuff
7220                          * since the async thread may not have started to do its
7221                          * work yet.  If this becomes the case then we need to
7222                          * figure out a way to make sure that in writepage we
7223                          * wait for any async pages to be submitted before
7224                          * returning so that fdatawait does what its supposed to
7225                          * do.
7226                          */
7227                         btrfs_wait_ordered_range(inode, 0, (u64)-1);
7228                 } else {
7229                         filemap_flush(inode->i_mapping);
7230                 }
7231                 if (delay_iput)
7232                         btrfs_add_delayed_iput(inode);
7233                 else
7234                         iput(inode);
7235                 return 1;
7236         }
7237         return 0;
7238 }
7239
7240 static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
7241                          const char *symname)
7242 {
7243         struct btrfs_trans_handle *trans;
7244         struct btrfs_root *root = BTRFS_I(dir)->root;
7245         struct btrfs_path *path;
7246         struct btrfs_key key;
7247         struct inode *inode = NULL;
7248         int err;
7249         int drop_inode = 0;
7250         u64 objectid;
7251         u64 index = 0 ;
7252         int name_len;
7253         int datasize;
7254         unsigned long ptr;
7255         struct btrfs_file_extent_item *ei;
7256         struct extent_buffer *leaf;
7257         unsigned long nr = 0;
7258
7259         name_len = strlen(symname) + 1;
7260         if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(root))
7261                 return -ENAMETOOLONG;
7262
7263         err = btrfs_find_free_objectid(NULL, root, dir->i_ino, &objectid);
7264         if (err)
7265                 return err;
7266         /*
7267          * 2 items for inode item and ref
7268          * 2 items for dir items
7269          * 1 item for xattr if selinux is on
7270          */
7271         trans = btrfs_start_transaction(root, 5);
7272         if (IS_ERR(trans))
7273                 return PTR_ERR(trans);
7274
7275         btrfs_set_trans_block_group(trans, dir);
7276
7277         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
7278                                 dentry->d_name.len, dir->i_ino, objectid,
7279                                 BTRFS_I(dir)->block_group, S_IFLNK|S_IRWXUGO,
7280                                 &index);
7281         err = PTR_ERR(inode);
7282         if (IS_ERR(inode))
7283                 goto out_unlock;
7284
7285         err = btrfs_init_inode_security(trans, inode, dir);
7286         if (err) {
7287                 drop_inode = 1;
7288                 goto out_unlock;
7289         }
7290
7291         btrfs_set_trans_block_group(trans, inode);
7292         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
7293         if (err)
7294                 drop_inode = 1;
7295         else {
7296                 inode->i_mapping->a_ops = &btrfs_aops;
7297                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
7298                 inode->i_fop = &btrfs_file_operations;
7299                 inode->i_op = &btrfs_file_inode_operations;
7300                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
7301         }
7302         btrfs_update_inode_block_group(trans, inode);
7303         btrfs_update_inode_block_group(trans, dir);
7304         if (drop_inode)
7305                 goto out_unlock;
7306
7307         path = btrfs_alloc_path();
7308         BUG_ON(!path);
7309         key.objectid = inode->i_ino;
7310         key.offset = 0;
7311         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
7312         datasize = btrfs_file_extent_calc_inline_size(name_len);
7313         err = btrfs_insert_empty_item(trans, root, path, &key,
7314                                       datasize);
7315         if (err) {
7316                 drop_inode = 1;
7317                 goto out_unlock;
7318         }
7319         leaf = path->nodes[0];
7320         ei = btrfs_item_ptr(leaf, path->slots[0],
7321                             struct btrfs_file_extent_item);
7322         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
7323         btrfs_set_file_extent_type(leaf, ei,
7324                                    BTRFS_FILE_EXTENT_INLINE);
7325         btrfs_set_file_extent_encryption(leaf, ei, 0);
7326         btrfs_set_file_extent_compression(leaf, ei, 0);
7327         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
7328         btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
7329
7330         ptr = btrfs_file_extent_inline_start(ei);
7331         write_extent_buffer(leaf, symname, ptr, name_len);
7332         btrfs_mark_buffer_dirty(leaf);
7333         btrfs_free_path(path);
7334
7335         inode->i_op = &btrfs_symlink_inode_operations;
7336         inode->i_mapping->a_ops = &btrfs_symlink_aops;
7337         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
7338         inode_set_bytes(inode, name_len);
7339         btrfs_i_size_write(inode, name_len - 1);
7340         err = btrfs_update_inode(trans, root, inode);
7341         if (err)
7342                 drop_inode = 1;
7343
7344 out_unlock:
7345         nr = trans->blocks_used;
7346         btrfs_end_transaction_throttle(trans, root);
7347         if (drop_inode) {
7348                 inode_dec_link_count(inode);
7349                 iput(inode);
7350         }
7351         btrfs_btree_balance_dirty(root, nr);
7352         return err;
7353 }
7354
7355 static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
7356                                        u64 start, u64 num_bytes, u64 min_size,
7357                                        loff_t actual_len, u64 *alloc_hint,
7358                                        struct btrfs_trans_handle *trans)
7359 {
7360         struct btrfs_root *root = BTRFS_I(inode)->root;
7361         struct btrfs_key ins;
7362         u64 cur_offset = start;
7363         u64 i_size;
7364         int ret = 0;
7365         bool own_trans = true;
7366
7367         if (trans)
7368                 own_trans = false;
7369         while (num_bytes > 0) {
7370                 if (own_trans) {
7371                         trans = btrfs_start_transaction(root, 3);
7372                         if (IS_ERR(trans)) {
7373                                 ret = PTR_ERR(trans);
7374                                 break;
7375                         }
7376                 }
7377
7378                 ret = btrfs_reserve_extent(trans, root, num_bytes, min_size,
7379                                            0, *alloc_hint, (u64)-1, &ins, 1);
7380                 if (ret) {
7381                         if (own_trans)
7382                                 btrfs_end_transaction(trans, root);
7383                         break;
7384                 }
7385
7386                 ret = insert_reserved_file_extent(trans, inode,
7387                                                   cur_offset, ins.objectid,
7388                                                   ins.offset, ins.offset,
7389                                                   ins.offset, 0, 0, 0,
7390                                                   BTRFS_FILE_EXTENT_PREALLOC);
7391                 BUG_ON(ret);
7392                 btrfs_drop_extent_cache(inode, cur_offset,
7393                                         cur_offset + ins.offset -1, 0);
7394
7395                 num_bytes -= ins.offset;
7396                 cur_offset += ins.offset;
7397                 *alloc_hint = ins.objectid + ins.offset;
7398
7399                 inode->i_ctime = CURRENT_TIME;
7400                 BTRFS_I(inode)->flags |= BTRFS_INODE_PREALLOC;
7401                 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
7402                     (actual_len > inode->i_size) &&
7403                     (cur_offset > inode->i_size)) {
7404                         if (cur_offset > actual_len)
7405                                 i_size = actual_len;
7406                         else
7407                                 i_size = cur_offset;
7408                         i_size_write(inode, i_size);
7409                         btrfs_ordered_update_i_size(inode, i_size, NULL);
7410                 }
7411
7412                 ret = btrfs_update_inode(trans, root, inode);
7413                 BUG_ON(ret);
7414
7415                 if (own_trans)
7416                         btrfs_end_transaction(trans, root);
7417         }
7418         return ret;
7419 }
7420
7421 int btrfs_prealloc_file_range(struct inode *inode, int mode,
7422                               u64 start, u64 num_bytes, u64 min_size,
7423                               loff_t actual_len, u64 *alloc_hint)
7424 {
7425         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
7426                                            min_size, actual_len, alloc_hint,
7427                                            NULL);
7428 }
7429
7430 int btrfs_prealloc_file_range_trans(struct inode *inode,
7431                                     struct btrfs_trans_handle *trans, int mode,
7432                                     u64 start, u64 num_bytes, u64 min_size,
7433                                     loff_t actual_len, u64 *alloc_hint)
7434 {
7435         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
7436                                            min_size, actual_len, alloc_hint, trans);
7437 }
7438
7439 static int btrfs_set_page_dirty(struct page *page)
7440 {
7441         return __set_page_dirty_nobuffers(page);
7442 }
7443
7444 static int btrfs_permission(struct inode *inode, int mask, unsigned int flags)
7445 {
7446         struct btrfs_root *root = BTRFS_I(inode)->root;
7447
7448         if (btrfs_root_readonly(root) && (mask & MAY_WRITE))
7449                 return -EROFS;
7450         if ((BTRFS_I(inode)->flags & BTRFS_INODE_READONLY) && (mask & MAY_WRITE))
7451                 return -EACCES;
7452         return generic_permission(inode, mask, flags, btrfs_check_acl);
7453 }
7454
7455 static const struct inode_operations btrfs_dir_inode_operations = {
7456         .getattr        = btrfs_getattr,
7457         .lookup         = btrfs_lookup,
7458         .create         = btrfs_create,
7459         .unlink         = btrfs_unlink,
7460         .link           = btrfs_link,
7461         .mkdir          = btrfs_mkdir,
7462         .rmdir          = btrfs_rmdir,
7463         .rename         = btrfs_rename,
7464         .symlink        = btrfs_symlink,
7465         .setattr        = btrfs_setattr,
7466         .mknod          = btrfs_mknod,
7467         .setxattr       = btrfs_setxattr,
7468         .getxattr       = btrfs_getxattr,
7469         .listxattr      = btrfs_listxattr,
7470         .removexattr    = btrfs_removexattr,
7471         .permission     = btrfs_permission,
7472 };
7473 static const struct inode_operations btrfs_dir_ro_inode_operations = {
7474         .lookup         = btrfs_lookup,
7475         .permission     = btrfs_permission,
7476 };
7477
7478 static const struct file_operations btrfs_dir_file_operations = {
7479         .llseek         = generic_file_llseek,
7480         .read           = generic_read_dir,
7481         .readdir        = btrfs_real_readdir,
7482         .unlocked_ioctl = btrfs_ioctl,
7483 #ifdef CONFIG_COMPAT
7484         .compat_ioctl   = btrfs_ioctl,
7485 #endif
7486         .release        = btrfs_release_file,
7487         .fsync          = btrfs_sync_file,
7488 };
7489
7490 static struct extent_io_ops btrfs_extent_io_ops = {
7491         .fill_delalloc = run_delalloc_range,
7492         .submit_bio_hook = btrfs_submit_bio_hook,
7493         .merge_bio_hook = btrfs_merge_bio_hook,
7494         .readpage_end_io_hook = btrfs_readpage_end_io_hook,
7495         .writepage_end_io_hook = btrfs_writepage_end_io_hook,
7496         .writepage_start_hook = btrfs_writepage_start_hook,
7497         .readpage_io_failed_hook = btrfs_io_failed_hook,
7498         .set_bit_hook = btrfs_set_bit_hook,
7499         .clear_bit_hook = btrfs_clear_bit_hook,
7500         .merge_extent_hook = btrfs_merge_extent_hook,
7501         .split_extent_hook = btrfs_split_extent_hook,
7502 };
7503
7504 /*
7505  * btrfs doesn't support the bmap operation because swapfiles
7506  * use bmap to make a mapping of extents in the file.  They assume
7507  * these extents won't change over the life of the file and they
7508  * use the bmap result to do IO directly to the drive.
7509  *
7510  * the btrfs bmap call would return logical addresses that aren't
7511  * suitable for IO and they also will change frequently as COW
7512  * operations happen.  So, swapfile + btrfs == corruption.
7513  *
7514  * For now we're avoiding this by dropping bmap.
7515  */
7516 static const struct address_space_operations btrfs_aops = {
7517         .readpage       = btrfs_readpage,
7518         .writepage      = btrfs_writepage,
7519         .writepages     = btrfs_writepages,
7520         .readpages      = btrfs_readpages,
7521         .sync_page      = block_sync_page,
7522         .direct_IO      = btrfs_direct_IO,
7523         .invalidatepage = btrfs_invalidatepage,
7524         .releasepage    = btrfs_releasepage,
7525         .set_page_dirty = btrfs_set_page_dirty,
7526         .error_remove_page = generic_error_remove_page,
7527 };
7528
7529 static const struct address_space_operations btrfs_symlink_aops = {
7530         .readpage       = btrfs_readpage,
7531         .writepage      = btrfs_writepage,
7532         .invalidatepage = btrfs_invalidatepage,
7533         .releasepage    = btrfs_releasepage,
7534 };
7535
7536 static const struct inode_operations btrfs_file_inode_operations = {
7537         .getattr        = btrfs_getattr,
7538         .setattr        = btrfs_setattr,
7539         .setxattr       = btrfs_setxattr,
7540         .getxattr       = btrfs_getxattr,
7541         .listxattr      = btrfs_listxattr,
7542         .removexattr    = btrfs_removexattr,
7543         .permission     = btrfs_permission,
7544         .fiemap         = btrfs_fiemap,
7545 };
7546 static const struct inode_operations btrfs_special_inode_operations = {
7547         .getattr        = btrfs_getattr,
7548         .setattr        = btrfs_setattr,
7549         .permission     = btrfs_permission,
7550         .setxattr       = btrfs_setxattr,
7551         .getxattr       = btrfs_getxattr,
7552         .listxattr      = btrfs_listxattr,
7553         .removexattr    = btrfs_removexattr,
7554 };
7555 static const struct inode_operations btrfs_symlink_inode_operations = {
7556         .readlink       = generic_readlink,
7557         .follow_link    = page_follow_link_light,
7558         .put_link       = page_put_link,
7559         .getattr        = btrfs_getattr,
7560         .permission     = btrfs_permission,
7561         .setxattr       = btrfs_setxattr,
7562         .getxattr       = btrfs_getxattr,
7563         .listxattr      = btrfs_listxattr,
7564         .removexattr    = btrfs_removexattr,
7565 };
7566
7567 const struct dentry_operations btrfs_dentry_operations = {
7568         .d_delete       = btrfs_dentry_delete,
7569 };