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inode.c
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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 <linux/ratelimit.h>
41 #include <linux/mount.h>
42 #include "compat.h"
43 #include "ctree.h"
44 #include "disk-io.h"
45 #include "transaction.h"
46 #include "btrfs_inode.h"
47 #include "ioctl.h"
48 #include "print-tree.h"
49 #include "ordered-data.h"
50 #include "xattr.h"
51 #include "tree-log.h"
52 #include "volumes.h"
53 #include "compression.h"
54 #include "locking.h"
55 #include "free-space-cache.h"
56 #include "inode-map.h"
57 
60  struct btrfs_root *root;
61 };
62 
63 static const struct inode_operations btrfs_dir_inode_operations;
64 static const struct inode_operations btrfs_symlink_inode_operations;
65 static const struct inode_operations btrfs_dir_ro_inode_operations;
66 static const struct inode_operations btrfs_special_inode_operations;
67 static const struct inode_operations btrfs_file_inode_operations;
68 static const struct address_space_operations btrfs_aops;
69 static const struct address_space_operations btrfs_symlink_aops;
70 static const struct file_operations btrfs_dir_file_operations;
71 static struct extent_io_ops btrfs_extent_io_ops;
72 
73 static struct kmem_cache *btrfs_inode_cachep;
78 
79 #define S_SHIFT 12
80 static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
88 };
89 
90 static int btrfs_setsize(struct inode *inode, loff_t newsize);
91 static int btrfs_truncate(struct inode *inode);
92 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent);
93 static noinline int cow_file_range(struct inode *inode,
94  struct page *locked_page,
95  u64 start, u64 end, int *page_started,
96  unsigned long *nr_written, int unlock);
97 
98 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
99  struct inode *inode, struct inode *dir,
100  const struct qstr *qstr)
101 {
102  int err;
103 
104  err = btrfs_init_acl(trans, inode, dir);
105  if (!err)
106  err = btrfs_xattr_security_init(trans, inode, dir, qstr);
107  return err;
108 }
109 
110 /*
111  * this does all the hard work for inserting an inline extent into
112  * the btree. The caller should have done a btrfs_drop_extents so that
113  * no overlapping inline items exist in the btree
114  */
115 static noinline int insert_inline_extent(struct btrfs_trans_handle *trans,
116  struct btrfs_root *root, struct inode *inode,
117  u64 start, size_t size, size_t compressed_size,
118  int compress_type,
119  struct page **compressed_pages)
120 {
121  struct btrfs_key key;
122  struct btrfs_path *path;
123  struct extent_buffer *leaf;
124  struct page *page = NULL;
125  char *kaddr;
126  unsigned long ptr;
127  struct btrfs_file_extent_item *ei;
128  int err = 0;
129  int ret;
130  size_t cur_size = size;
131  size_t datasize;
132  unsigned long offset;
133 
134  if (compressed_size && compressed_pages)
135  cur_size = compressed_size;
136 
137  path = btrfs_alloc_path();
138  if (!path)
139  return -ENOMEM;
140 
141  path->leave_spinning = 1;
142 
143  key.objectid = btrfs_ino(inode);
144  key.offset = start;
145  btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
146  datasize = btrfs_file_extent_calc_inline_size(cur_size);
147 
148  inode_add_bytes(inode, size);
149  ret = btrfs_insert_empty_item(trans, root, path, &key,
150  datasize);
151  if (ret) {
152  err = ret;
153  goto fail;
154  }
155  leaf = path->nodes[0];
156  ei = btrfs_item_ptr(leaf, path->slots[0],
157  struct btrfs_file_extent_item);
158  btrfs_set_file_extent_generation(leaf, ei, trans->transid);
159  btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
160  btrfs_set_file_extent_encryption(leaf, ei, 0);
161  btrfs_set_file_extent_other_encoding(leaf, ei, 0);
162  btrfs_set_file_extent_ram_bytes(leaf, ei, size);
163  ptr = btrfs_file_extent_inline_start(ei);
164 
165  if (compress_type != BTRFS_COMPRESS_NONE) {
166  struct page *cpage;
167  int i = 0;
168  while (compressed_size > 0) {
169  cpage = compressed_pages[i];
170  cur_size = min_t(unsigned long, compressed_size,
172 
173  kaddr = kmap_atomic(cpage);
174  write_extent_buffer(leaf, kaddr, ptr, cur_size);
175  kunmap_atomic(kaddr);
176 
177  i++;
178  ptr += cur_size;
179  compressed_size -= cur_size;
180  }
181  btrfs_set_file_extent_compression(leaf, ei,
182  compress_type);
183  } else {
184  page = find_get_page(inode->i_mapping,
185  start >> PAGE_CACHE_SHIFT);
186  btrfs_set_file_extent_compression(leaf, ei, 0);
187  kaddr = kmap_atomic(page);
188  offset = start & (PAGE_CACHE_SIZE - 1);
189  write_extent_buffer(leaf, kaddr + offset, ptr, size);
190  kunmap_atomic(kaddr);
191  page_cache_release(page);
192  }
194  btrfs_free_path(path);
195 
196  /*
197  * we're an inline extent, so nobody can
198  * extend the file past i_size without locking
199  * a page we already have locked.
200  *
201  * We must do any isize and inode updates
202  * before we unlock the pages. Otherwise we
203  * could end up racing with unlink.
204  */
205  BTRFS_I(inode)->disk_i_size = inode->i_size;
206  ret = btrfs_update_inode(trans, root, inode);
207 
208  return ret;
209 fail:
210  btrfs_free_path(path);
211  return err;
212 }
213 
214 
215 /*
216  * conditionally insert an inline extent into the file. This
217  * does the checks required to make sure the data is small enough
218  * to fit as an inline extent.
219  */
220 static noinline int cow_file_range_inline(struct btrfs_trans_handle *trans,
221  struct btrfs_root *root,
222  struct inode *inode, u64 start, u64 end,
223  size_t compressed_size, int compress_type,
224  struct page **compressed_pages)
225 {
226  u64 isize = i_size_read(inode);
227  u64 actual_end = min(end + 1, isize);
228  u64 inline_len = actual_end - start;
229  u64 aligned_end = (end + root->sectorsize - 1) &
230  ~((u64)root->sectorsize - 1);
231  u64 data_len = inline_len;
232  int ret;
233 
234  if (compressed_size)
235  data_len = compressed_size;
236 
237  if (start > 0 ||
238  actual_end >= PAGE_CACHE_SIZE ||
239  data_len >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
240  (!compressed_size &&
241  (actual_end & (root->sectorsize - 1)) == 0) ||
242  end + 1 < isize ||
243  data_len > root->fs_info->max_inline) {
244  return 1;
245  }
246 
247  ret = btrfs_drop_extents(trans, root, inode, start, aligned_end, 1);
248  if (ret)
249  return ret;
250 
251  if (isize > actual_end)
252  inline_len = min_t(u64, isize, actual_end);
253  ret = insert_inline_extent(trans, root, inode, start,
254  inline_len, compressed_size,
255  compress_type, compressed_pages);
256  if (ret && ret != -ENOSPC) {
257  btrfs_abort_transaction(trans, root, ret);
258  return ret;
259  } else if (ret == -ENOSPC) {
260  return 1;
261  }
262 
263  btrfs_delalloc_release_metadata(inode, end + 1 - start);
264  btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
265  return 0;
266 }
267 
268 struct async_extent {
272  struct page **pages;
273  unsigned long nr_pages;
275  struct list_head list;
276 };
277 
278 struct async_cow {
279  struct inode *inode;
280  struct btrfs_root *root;
281  struct page *locked_page;
285  struct btrfs_work work;
286 };
287 
288 static noinline int add_async_extent(struct async_cow *cow,
289  u64 start, u64 ram_size,
290  u64 compressed_size,
291  struct page **pages,
292  unsigned long nr_pages,
293  int compress_type)
294 {
295  struct async_extent *async_extent;
296 
297  async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
298  BUG_ON(!async_extent); /* -ENOMEM */
299  async_extent->start = start;
300  async_extent->ram_size = ram_size;
301  async_extent->compressed_size = compressed_size;
302  async_extent->pages = pages;
303  async_extent->nr_pages = nr_pages;
304  async_extent->compress_type = compress_type;
305  list_add_tail(&async_extent->list, &cow->extents);
306  return 0;
307 }
308 
309 /*
310  * we create compressed extents in two phases. The first
311  * phase compresses a range of pages that have already been
312  * locked (both pages and state bits are locked).
313  *
314  * This is done inside an ordered work queue, and the compression
315  * is spread across many cpus. The actual IO submission is step
316  * two, and the ordered work queue takes care of making sure that
317  * happens in the same order things were put onto the queue by
318  * writepages and friends.
319  *
320  * If this code finds it can't get good compression, it puts an
321  * entry onto the work queue to write the uncompressed bytes. This
322  * makes sure that both compressed inodes and uncompressed inodes
323  * are written in the same order that the flusher thread sent them
324  * down.
325  */
326 static noinline int compress_file_range(struct inode *inode,
327  struct page *locked_page,
328  u64 start, u64 end,
329  struct async_cow *async_cow,
330  int *num_added)
331 {
332  struct btrfs_root *root = BTRFS_I(inode)->root;
333  struct btrfs_trans_handle *trans;
334  u64 num_bytes;
335  u64 blocksize = root->sectorsize;
336  u64 actual_end;
337  u64 isize = i_size_read(inode);
338  int ret = 0;
339  struct page **pages = NULL;
340  unsigned long nr_pages;
341  unsigned long nr_pages_ret = 0;
342  unsigned long total_compressed = 0;
343  unsigned long total_in = 0;
344  unsigned long max_compressed = 128 * 1024;
345  unsigned long max_uncompressed = 128 * 1024;
346  int i;
347  int will_compress;
348  int compress_type = root->fs_info->compress_type;
349 
350  /* if this is a small write inside eof, kick off a defrag */
351  if ((end - start + 1) < 16 * 1024 &&
352  (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
354 
355  actual_end = min_t(u64, isize, end + 1);
356 again:
357  will_compress = 0;
358  nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1;
359  nr_pages = min(nr_pages, (128 * 1024UL) / PAGE_CACHE_SIZE);
360 
361  /*
362  * we don't want to send crud past the end of i_size through
363  * compression, that's just a waste of CPU time. So, if the
364  * end of the file is before the start of our current
365  * requested range of bytes, we bail out to the uncompressed
366  * cleanup code that can deal with all of this.
367  *
368  * It isn't really the fastest way to fix things, but this is a
369  * very uncommon corner.
370  */
371  if (actual_end <= start)
372  goto cleanup_and_bail_uncompressed;
373 
374  total_compressed = actual_end - start;
375 
376  /* we want to make sure that amount of ram required to uncompress
377  * an extent is reasonable, so we limit the total size in ram
378  * of a compressed extent to 128k. This is a crucial number
379  * because it also controls how easily we can spread reads across
380  * cpus for decompression.
381  *
382  * We also want to make sure the amount of IO required to do
383  * a random read is reasonably small, so we limit the size of
384  * a compressed extent to 128k.
385  */
386  total_compressed = min(total_compressed, max_uncompressed);
387  num_bytes = (end - start + blocksize) & ~(blocksize - 1);
388  num_bytes = max(blocksize, num_bytes);
389  total_in = 0;
390  ret = 0;
391 
392  /*
393  * we do compression for mount -o compress and when the
394  * inode has not been flagged as nocompress. This flag can
395  * change at any time if we discover bad compression ratios.
396  */
397  if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS) &&
398  (btrfs_test_opt(root, COMPRESS) ||
399  (BTRFS_I(inode)->force_compress) ||
400  (BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS))) {
401  WARN_ON(pages);
402  pages = kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
403  if (!pages) {
404  /* just bail out to the uncompressed code */
405  goto cont;
406  }
407 
408  if (BTRFS_I(inode)->force_compress)
409  compress_type = BTRFS_I(inode)->force_compress;
410 
411  ret = btrfs_compress_pages(compress_type,
412  inode->i_mapping, start,
413  total_compressed, pages,
414  nr_pages, &nr_pages_ret,
415  &total_in,
416  &total_compressed,
417  max_compressed);
418 
419  if (!ret) {
420  unsigned long offset = total_compressed &
421  (PAGE_CACHE_SIZE - 1);
422  struct page *page = pages[nr_pages_ret - 1];
423  char *kaddr;
424 
425  /* zero the tail end of the last page, we might be
426  * sending it down to disk
427  */
428  if (offset) {
429  kaddr = kmap_atomic(page);
430  memset(kaddr + offset, 0,
431  PAGE_CACHE_SIZE - offset);
432  kunmap_atomic(kaddr);
433  }
434  will_compress = 1;
435  }
436  }
437 cont:
438  if (start == 0) {
439  trans = btrfs_join_transaction(root);
440  if (IS_ERR(trans)) {
441  ret = PTR_ERR(trans);
442  trans = NULL;
443  goto cleanup_and_out;
444  }
445  trans->block_rsv = &root->fs_info->delalloc_block_rsv;
446 
447  /* lets try to make an inline extent */
448  if (ret || total_in < (actual_end - start)) {
449  /* we didn't compress the entire range, try
450  * to make an uncompressed inline extent.
451  */
452  ret = cow_file_range_inline(trans, root, inode,
453  start, end, 0, 0, NULL);
454  } else {
455  /* try making a compressed inline extent */
456  ret = cow_file_range_inline(trans, root, inode,
457  start, end,
458  total_compressed,
459  compress_type, pages);
460  }
461  if (ret <= 0) {
462  /*
463  * inline extent creation worked or returned error,
464  * we don't need to create any more async work items.
465  * Unlock and free up our temp pages.
466  */
468  &BTRFS_I(inode)->io_tree,
469  start, end, NULL,
473 
474  btrfs_end_transaction(trans, root);
475  goto free_pages_out;
476  }
477  btrfs_end_transaction(trans, root);
478  }
479 
480  if (will_compress) {
481  /*
482  * we aren't doing an inline extent round the compressed size
483  * up to a block size boundary so the allocator does sane
484  * things
485  */
486  total_compressed = (total_compressed + blocksize - 1) &
487  ~(blocksize - 1);
488 
489  /*
490  * one last check to make sure the compression is really a
491  * win, compare the page count read with the blocks on disk
492  */
493  total_in = (total_in + PAGE_CACHE_SIZE - 1) &
494  ~(PAGE_CACHE_SIZE - 1);
495  if (total_compressed >= total_in) {
496  will_compress = 0;
497  } else {
498  num_bytes = total_in;
499  }
500  }
501  if (!will_compress && pages) {
502  /*
503  * the compression code ran but failed to make things smaller,
504  * free any pages it allocated and our page pointer array
505  */
506  for (i = 0; i < nr_pages_ret; i++) {
507  WARN_ON(pages[i]->mapping);
508  page_cache_release(pages[i]);
509  }
510  kfree(pages);
511  pages = NULL;
512  total_compressed = 0;
513  nr_pages_ret = 0;
514 
515  /* flag the file so we don't compress in the future */
516  if (!btrfs_test_opt(root, FORCE_COMPRESS) &&
517  !(BTRFS_I(inode)->force_compress)) {
518  BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
519  }
520  }
521  if (will_compress) {
522  *num_added += 1;
523 
524  /* the async work queues will take care of doing actual
525  * allocation on disk for these compressed pages,
526  * and will submit them to the elevator.
527  */
528  add_async_extent(async_cow, start, num_bytes,
529  total_compressed, pages, nr_pages_ret,
530  compress_type);
531 
532  if (start + num_bytes < end) {
533  start += num_bytes;
534  pages = NULL;
535  cond_resched();
536  goto again;
537  }
538  } else {
539 cleanup_and_bail_uncompressed:
540  /*
541  * No compression, but we still need to write the pages in
542  * the file we've been given so far. redirty the locked
543  * page if it corresponds to our extent and set things up
544  * for the async work queue to run cow_file_range to do
545  * the normal delalloc dance
546  */
547  if (page_offset(locked_page) >= start &&
548  page_offset(locked_page) <= end) {
549  __set_page_dirty_nobuffers(locked_page);
550  /* unlocked later on in the async handlers */
551  }
552  add_async_extent(async_cow, start, end - start + 1,
553  0, NULL, 0, BTRFS_COMPRESS_NONE);
554  *num_added += 1;
555  }
556 
557 out:
558  return ret;
559 
560 free_pages_out:
561  for (i = 0; i < nr_pages_ret; i++) {
562  WARN_ON(pages[i]->mapping);
563  page_cache_release(pages[i]);
564  }
565  kfree(pages);
566 
567  goto out;
568 
569 cleanup_and_out:
570  extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
571  start, end, NULL,
577  if (!trans || IS_ERR(trans))
578  btrfs_error(root->fs_info, ret, "Failed to join transaction");
579  else
580  btrfs_abort_transaction(trans, root, ret);
581  goto free_pages_out;
582 }
583 
584 /*
585  * phase two of compressed writeback. This is the ordered portion
586  * of the code, which only gets called in the order the work was
587  * queued. We walk all the async extents created by compress_file_range
588  * and send them down to the disk.
589  */
590 static noinline int submit_compressed_extents(struct inode *inode,
591  struct async_cow *async_cow)
592 {
593  struct async_extent *async_extent;
594  u64 alloc_hint = 0;
595  struct btrfs_trans_handle *trans;
596  struct btrfs_key ins;
597  struct extent_map *em;
598  struct btrfs_root *root = BTRFS_I(inode)->root;
599  struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
600  struct extent_io_tree *io_tree;
601  int ret = 0;
602 
603  if (list_empty(&async_cow->extents))
604  return 0;
605 
606 
607  while (!list_empty(&async_cow->extents)) {
608  async_extent = list_entry(async_cow->extents.next,
609  struct async_extent, list);
610  list_del(&async_extent->list);
611 
612  io_tree = &BTRFS_I(inode)->io_tree;
613 
614 retry:
615  /* did the compression code fall back to uncompressed IO? */
616  if (!async_extent->pages) {
617  int page_started = 0;
618  unsigned long nr_written = 0;
619 
620  lock_extent(io_tree, async_extent->start,
621  async_extent->start +
622  async_extent->ram_size - 1);
623 
624  /* allocate blocks */
625  ret = cow_file_range(inode, async_cow->locked_page,
626  async_extent->start,
627  async_extent->start +
628  async_extent->ram_size - 1,
629  &page_started, &nr_written, 0);
630 
631  /* JDM XXX */
632 
633  /*
634  * if page_started, cow_file_range inserted an
635  * inline extent and took care of all the unlocking
636  * and IO for us. Otherwise, we need to submit
637  * all those pages down to the drive.
638  */
639  if (!page_started && !ret)
641  inode, async_extent->start,
642  async_extent->start +
643  async_extent->ram_size - 1,
645  WB_SYNC_ALL);
646  kfree(async_extent);
647  cond_resched();
648  continue;
649  }
650 
651  lock_extent(io_tree, async_extent->start,
652  async_extent->start + async_extent->ram_size - 1);
653 
654  trans = btrfs_join_transaction(root);
655  if (IS_ERR(trans)) {
656  ret = PTR_ERR(trans);
657  } else {
658  trans->block_rsv = &root->fs_info->delalloc_block_rsv;
659  ret = btrfs_reserve_extent(trans, root,
660  async_extent->compressed_size,
661  async_extent->compressed_size,
662  0, alloc_hint, &ins, 1);
663  if (ret && ret != -ENOSPC)
664  btrfs_abort_transaction(trans, root, ret);
665  btrfs_end_transaction(trans, root);
666  }
667 
668  if (ret) {
669  int i;
670  for (i = 0; i < async_extent->nr_pages; i++) {
671  WARN_ON(async_extent->pages[i]->mapping);
672  page_cache_release(async_extent->pages[i]);
673  }
674  kfree(async_extent->pages);
675  async_extent->nr_pages = 0;
676  async_extent->pages = NULL;
677  unlock_extent(io_tree, async_extent->start,
678  async_extent->start +
679  async_extent->ram_size - 1);
680  if (ret == -ENOSPC)
681  goto retry;
682  goto out_free; /* JDM: Requeue? */
683  }
684 
685  /*
686  * here we're doing allocation and writeback of the
687  * compressed pages
688  */
689  btrfs_drop_extent_cache(inode, async_extent->start,
690  async_extent->start +
691  async_extent->ram_size - 1, 0);
692 
693  em = alloc_extent_map();
694  BUG_ON(!em); /* -ENOMEM */
695  em->start = async_extent->start;
696  em->len = async_extent->ram_size;
697  em->orig_start = em->start;
698 
699  em->block_start = ins.objectid;
700  em->block_len = ins.offset;
701  em->bdev = root->fs_info->fs_devices->latest_bdev;
702  em->compress_type = async_extent->compress_type;
705 
706  while (1) {
707  write_lock(&em_tree->lock);
708  ret = add_extent_mapping(em_tree, em);
709  write_unlock(&em_tree->lock);
710  if (ret != -EEXIST) {
711  free_extent_map(em);
712  break;
713  }
714  btrfs_drop_extent_cache(inode, async_extent->start,
715  async_extent->start +
716  async_extent->ram_size - 1, 0);
717  }
718 
720  async_extent->start,
721  ins.objectid,
722  async_extent->ram_size,
723  ins.offset,
725  async_extent->compress_type);
726  BUG_ON(ret); /* -ENOMEM */
727 
728  /*
729  * clear dirty, set writeback and unlock the pages.
730  */
732  &BTRFS_I(inode)->io_tree,
733  async_extent->start,
734  async_extent->start +
735  async_extent->ram_size - 1,
740 
741  ret = btrfs_submit_compressed_write(inode,
742  async_extent->start,
743  async_extent->ram_size,
744  ins.objectid,
745  ins.offset, async_extent->pages,
746  async_extent->nr_pages);
747 
748  BUG_ON(ret); /* -ENOMEM */
749  alloc_hint = ins.objectid + ins.offset;
750  kfree(async_extent);
751  cond_resched();
752  }
753  ret = 0;
754 out:
755  return ret;
756 out_free:
757  kfree(async_extent);
758  goto out;
759 }
760 
761 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
762  u64 num_bytes)
763 {
764  struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
765  struct extent_map *em;
766  u64 alloc_hint = 0;
767 
768  read_lock(&em_tree->lock);
769  em = search_extent_mapping(em_tree, start, num_bytes);
770  if (em) {
771  /*
772  * if block start isn't an actual block number then find the
773  * first block in this inode and use that as a hint. If that
774  * block is also bogus then just don't worry about it.
775  */
776  if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
777  free_extent_map(em);
778  em = search_extent_mapping(em_tree, 0, 0);
779  if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
780  alloc_hint = em->block_start;
781  if (em)
782  free_extent_map(em);
783  } else {
784  alloc_hint = em->block_start;
785  free_extent_map(em);
786  }
787  }
788  read_unlock(&em_tree->lock);
789 
790  return alloc_hint;
791 }
792 
793 /*
794  * when extent_io.c finds a delayed allocation range in the file,
795  * the call backs end up in this code. The basic idea is to
796  * allocate extents on disk for the range, and create ordered data structs
797  * in ram to track those extents.
798  *
799  * locked_page is the page that writepage had locked already. We use
800  * it to make sure we don't do extra locks or unlocks.
801  *
802  * *page_started is set to one if we unlock locked_page and do everything
803  * required to start IO on it. It may be clean and already done with
804  * IO when we return.
805  */
806 static noinline int cow_file_range(struct inode *inode,
807  struct page *locked_page,
808  u64 start, u64 end, int *page_started,
809  unsigned long *nr_written,
810  int unlock)
811 {
812  struct btrfs_root *root = BTRFS_I(inode)->root;
813  struct btrfs_trans_handle *trans;
814  u64 alloc_hint = 0;
815  u64 num_bytes;
816  unsigned long ram_size;
818  u64 cur_alloc_size;
819  u64 blocksize = root->sectorsize;
820  struct btrfs_key ins;
821  struct extent_map *em;
822  struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
823  int ret = 0;
824 
825  BUG_ON(btrfs_is_free_space_inode(inode));
826  trans = btrfs_join_transaction(root);
827  if (IS_ERR(trans)) {
829  &BTRFS_I(inode)->io_tree,
830  start, end, locked_page,
837  return PTR_ERR(trans);
838  }
839  trans->block_rsv = &root->fs_info->delalloc_block_rsv;
840 
841  num_bytes = (end - start + blocksize) & ~(blocksize - 1);
842  num_bytes = max(blocksize, num_bytes);
843  disk_num_bytes = num_bytes;
844  ret = 0;
845 
846  /* if this is a small write inside eof, kick off defrag */
847  if (num_bytes < 64 * 1024 &&
848  (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
849  btrfs_add_inode_defrag(trans, inode);
850 
851  if (start == 0) {
852  /* lets try to make an inline extent */
853  ret = cow_file_range_inline(trans, root, inode,
854  start, end, 0, 0, NULL);
855  if (ret == 0) {
857  &BTRFS_I(inode)->io_tree,
858  start, end, NULL,
865 
866  *nr_written = *nr_written +
867  (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
868  *page_started = 1;
869  goto out;
870  } else if (ret < 0) {
871  btrfs_abort_transaction(trans, root, ret);
872  goto out_unlock;
873  }
874  }
875 
876  BUG_ON(disk_num_bytes >
877  btrfs_super_total_bytes(root->fs_info->super_copy));
878 
879  alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
880  btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
881 
882  while (disk_num_bytes > 0) {
883  unsigned long op;
884 
885  cur_alloc_size = disk_num_bytes;
886  ret = btrfs_reserve_extent(trans, root, cur_alloc_size,
887  root->sectorsize, 0, alloc_hint,
888  &ins, 1);
889  if (ret < 0) {
890  btrfs_abort_transaction(trans, root, ret);
891  goto out_unlock;
892  }
893 
894  em = alloc_extent_map();
895  BUG_ON(!em); /* -ENOMEM */
896  em->start = start;
897  em->orig_start = em->start;
898  ram_size = ins.offset;
899  em->len = ins.offset;
900 
901  em->block_start = ins.objectid;
902  em->block_len = ins.offset;
903  em->bdev = root->fs_info->fs_devices->latest_bdev;
905 
906  while (1) {
907  write_lock(&em_tree->lock);
908  ret = add_extent_mapping(em_tree, em);
909  write_unlock(&em_tree->lock);
910  if (ret != -EEXIST) {
911  free_extent_map(em);
912  break;
913  }
914  btrfs_drop_extent_cache(inode, start,
915  start + ram_size - 1, 0);
916  }
917 
918  cur_alloc_size = ins.offset;
919  ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
920  ram_size, cur_alloc_size, 0);
921  BUG_ON(ret); /* -ENOMEM */
922 
923  if (root->root_key.objectid ==
925  ret = btrfs_reloc_clone_csums(inode, start,
926  cur_alloc_size);
927  if (ret) {
928  btrfs_abort_transaction(trans, root, ret);
929  goto out_unlock;
930  }
931  }
932 
933  if (disk_num_bytes < cur_alloc_size)
934  break;
935 
936  /* we're not doing compressed IO, don't unlock the first
937  * page (which the caller expects to stay locked), don't
938  * clear any dirty bits and don't set any writeback bits
939  *
940  * Do set the Private2 bit so we know this page was properly
941  * setup for writepage
942  */
943  op = unlock ? EXTENT_CLEAR_UNLOCK_PAGE : 0;
946 
947  extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
948  start, start + ram_size - 1,
949  locked_page, op);
950  disk_num_bytes -= cur_alloc_size;
951  num_bytes -= cur_alloc_size;
952  alloc_hint = ins.objectid + ins.offset;
953  start += cur_alloc_size;
954  }
955  ret = 0;
956 out:
957  btrfs_end_transaction(trans, root);
958 
959  return ret;
960 out_unlock:
962  &BTRFS_I(inode)->io_tree,
963  start, end, locked_page,
970 
971  goto out;
972 }
973 
974 /*
975  * work queue call back to started compression on a file and pages
976  */
977 static noinline void async_cow_start(struct btrfs_work *work)
978 {
979  struct async_cow *async_cow;
980  int num_added = 0;
981  async_cow = container_of(work, struct async_cow, work);
982 
983  compress_file_range(async_cow->inode, async_cow->locked_page,
984  async_cow->start, async_cow->end, async_cow,
985  &num_added);
986  if (num_added == 0) {
987  btrfs_add_delayed_iput(async_cow->inode);
988  async_cow->inode = NULL;
989  }
990 }
991 
992 /*
993  * work queue call back to submit previously compressed pages
994  */
995 static noinline void async_cow_submit(struct btrfs_work *work)
996 {
997  struct async_cow *async_cow;
998  struct btrfs_root *root;
999  unsigned long nr_pages;
1000 
1001  async_cow = container_of(work, struct async_cow, work);
1002 
1003  root = async_cow->root;
1004  nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >>
1006 
1007  if (atomic_sub_return(nr_pages, &root->fs_info->async_delalloc_pages) <
1008  5 * 1024 * 1024 &&
1009  waitqueue_active(&root->fs_info->async_submit_wait))
1010  wake_up(&root->fs_info->async_submit_wait);
1011 
1012  if (async_cow->inode)
1013  submit_compressed_extents(async_cow->inode, async_cow);
1014 }
1015 
1016 static noinline void async_cow_free(struct btrfs_work *work)
1017 {
1018  struct async_cow *async_cow;
1019  async_cow = container_of(work, struct async_cow, work);
1020  if (async_cow->inode)
1021  btrfs_add_delayed_iput(async_cow->inode);
1022  kfree(async_cow);
1023 }
1024 
1025 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
1026  u64 start, u64 end, int *page_started,
1027  unsigned long *nr_written)
1028 {
1029  struct async_cow *async_cow;
1030  struct btrfs_root *root = BTRFS_I(inode)->root;
1031  unsigned long nr_pages;
1032  u64 cur_end;
1033  int limit = 10 * 1024 * 1024;
1034 
1035  clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
1036  1, 0, NULL, GFP_NOFS);
1037  while (start < end) {
1038  async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
1039  BUG_ON(!async_cow); /* -ENOMEM */
1040  async_cow->inode = igrab(inode);
1041  async_cow->root = root;
1042  async_cow->locked_page = locked_page;
1043  async_cow->start = start;
1044 
1045  if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
1046  cur_end = end;
1047  else
1048  cur_end = min(end, start + 512 * 1024 - 1);
1049 
1050  async_cow->end = cur_end;
1051  INIT_LIST_HEAD(&async_cow->extents);
1052 
1053  async_cow->work.func = async_cow_start;
1054  async_cow->work.ordered_func = async_cow_submit;
1055  async_cow->work.ordered_free = async_cow_free;
1056  async_cow->work.flags = 0;
1057 
1058  nr_pages = (cur_end - start + PAGE_CACHE_SIZE) >>
1060  atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
1061 
1062  btrfs_queue_worker(&root->fs_info->delalloc_workers,
1063  &async_cow->work);
1064 
1065  if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
1066  wait_event(root->fs_info->async_submit_wait,
1067  (atomic_read(&root->fs_info->async_delalloc_pages) <
1068  limit));
1069  }
1070 
1071  while (atomic_read(&root->fs_info->async_submit_draining) &&
1072  atomic_read(&root->fs_info->async_delalloc_pages)) {
1073  wait_event(root->fs_info->async_submit_wait,
1074  (atomic_read(&root->fs_info->async_delalloc_pages) ==
1075  0));
1076  }
1077 
1078  *nr_written += nr_pages;
1079  start = cur_end + 1;
1080  }
1081  *page_started = 1;
1082  return 0;
1083 }
1084 
1085 static noinline int csum_exist_in_range(struct btrfs_root *root,
1086  u64 bytenr, u64 num_bytes)
1087 {
1088  int ret;
1089  struct btrfs_ordered_sum *sums;
1090  LIST_HEAD(list);
1091 
1092  ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
1093  bytenr + num_bytes - 1, &list, 0);
1094  if (ret == 0 && list_empty(&list))
1095  return 0;
1096 
1097  while (!list_empty(&list)) {
1098  sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1099  list_del(&sums->list);
1100  kfree(sums);
1101  }
1102  return 1;
1103 }
1104 
1105 /*
1106  * when nowcow writeback call back. This checks for snapshots or COW copies
1107  * of the extents that exist in the file, and COWs the file as required.
1108  *
1109  * If no cow copies or snapshots exist, we write directly to the existing
1110  * blocks on disk
1111  */
1112 static noinline int run_delalloc_nocow(struct inode *inode,
1113  struct page *locked_page,
1114  u64 start, u64 end, int *page_started, int force,
1115  unsigned long *nr_written)
1116 {
1117  struct btrfs_root *root = BTRFS_I(inode)->root;
1118  struct btrfs_trans_handle *trans;
1119  struct extent_buffer *leaf;
1120  struct btrfs_path *path;
1121  struct btrfs_file_extent_item *fi;
1122  struct btrfs_key found_key;
1123  u64 cow_start;
1124  u64 cur_offset;
1125  u64 extent_end;
1126  u64 extent_offset;
1127  u64 disk_bytenr;
1128  u64 num_bytes;
1129  int extent_type;
1130  int ret, err;
1131  int type;
1132  int nocow;
1133  int check_prev = 1;
1134  bool nolock;
1135  u64 ino = btrfs_ino(inode);
1136 
1137  path = btrfs_alloc_path();
1138  if (!path) {
1140  &BTRFS_I(inode)->io_tree,
1141  start, end, locked_page,
1148  return -ENOMEM;
1149  }
1150 
1151  nolock = btrfs_is_free_space_inode(inode);
1152 
1153  if (nolock)
1154  trans = btrfs_join_transaction_nolock(root);
1155  else
1156  trans = btrfs_join_transaction(root);
1157 
1158  if (IS_ERR(trans)) {
1160  &BTRFS_I(inode)->io_tree,
1161  start, end, locked_page,
1168  btrfs_free_path(path);
1169  return PTR_ERR(trans);
1170  }
1171 
1172  trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1173 
1174  cow_start = (u64)-1;
1175  cur_offset = start;
1176  while (1) {
1177  ret = btrfs_lookup_file_extent(trans, root, path, ino,
1178  cur_offset, 0);
1179  if (ret < 0) {
1180  btrfs_abort_transaction(trans, root, ret);
1181  goto error;
1182  }
1183  if (ret > 0 && path->slots[0] > 0 && check_prev) {
1184  leaf = path->nodes[0];
1185  btrfs_item_key_to_cpu(leaf, &found_key,
1186  path->slots[0] - 1);
1187  if (found_key.objectid == ino &&
1188  found_key.type == BTRFS_EXTENT_DATA_KEY)
1189  path->slots[0]--;
1190  }
1191  check_prev = 0;
1192 next_slot:
1193  leaf = path->nodes[0];
1194  if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1195  ret = btrfs_next_leaf(root, path);
1196  if (ret < 0) {
1197  btrfs_abort_transaction(trans, root, ret);
1198  goto error;
1199  }
1200  if (ret > 0)
1201  break;
1202  leaf = path->nodes[0];
1203  }
1204 
1205  nocow = 0;
1206  disk_bytenr = 0;
1207  num_bytes = 0;
1208  btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1209 
1210  if (found_key.objectid > ino ||
1211  found_key.type > BTRFS_EXTENT_DATA_KEY ||
1212  found_key.offset > end)
1213  break;
1214 
1215  if (found_key.offset > cur_offset) {
1216  extent_end = found_key.offset;
1217  extent_type = 0;
1218  goto out_check;
1219  }
1220 
1221  fi = btrfs_item_ptr(leaf, path->slots[0],
1222  struct btrfs_file_extent_item);
1223  extent_type = btrfs_file_extent_type(leaf, fi);
1224 
1225  if (extent_type == BTRFS_FILE_EXTENT_REG ||
1226  extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1227  disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1228  extent_offset = btrfs_file_extent_offset(leaf, fi);
1229  extent_end = found_key.offset +
1230  btrfs_file_extent_num_bytes(leaf, fi);
1231  if (extent_end <= start) {
1232  path->slots[0]++;
1233  goto next_slot;
1234  }
1235  if (disk_bytenr == 0)
1236  goto out_check;
1237  if (btrfs_file_extent_compression(leaf, fi) ||
1238  btrfs_file_extent_encryption(leaf, fi) ||
1239  btrfs_file_extent_other_encoding(leaf, fi))
1240  goto out_check;
1241  if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1242  goto out_check;
1243  if (btrfs_extent_readonly(root, disk_bytenr))
1244  goto out_check;
1245  if (btrfs_cross_ref_exist(trans, root, ino,
1246  found_key.offset -
1247  extent_offset, disk_bytenr))
1248  goto out_check;
1249  disk_bytenr += extent_offset;
1250  disk_bytenr += cur_offset - found_key.offset;
1251  num_bytes = min(end + 1, extent_end) - cur_offset;
1252  /*
1253  * force cow if csum exists in the range.
1254  * this ensure that csum for a given extent are
1255  * either valid or do not exist.
1256  */
1257  if (csum_exist_in_range(root, disk_bytenr, num_bytes))
1258  goto out_check;
1259  nocow = 1;
1260  } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1261  extent_end = found_key.offset +
1262  btrfs_file_extent_inline_len(leaf, fi);
1263  extent_end = ALIGN(extent_end, root->sectorsize);
1264  } else {
1265  BUG_ON(1);
1266  }
1267 out_check:
1268  if (extent_end <= start) {
1269  path->slots[0]++;
1270  goto next_slot;
1271  }
1272  if (!nocow) {
1273  if (cow_start == (u64)-1)
1274  cow_start = cur_offset;
1275  cur_offset = extent_end;
1276  if (cur_offset > end)
1277  break;
1278  path->slots[0]++;
1279  goto next_slot;
1280  }
1281 
1282  btrfs_release_path(path);
1283  if (cow_start != (u64)-1) {
1284  ret = cow_file_range(inode, locked_page, cow_start,
1285  found_key.offset - 1, page_started,
1286  nr_written, 1);
1287  if (ret) {
1288  btrfs_abort_transaction(trans, root, ret);
1289  goto error;
1290  }
1291  cow_start = (u64)-1;
1292  }
1293 
1294  if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1295  struct extent_map *em;
1296  struct extent_map_tree *em_tree;
1297  em_tree = &BTRFS_I(inode)->extent_tree;
1298  em = alloc_extent_map();
1299  BUG_ON(!em); /* -ENOMEM */
1300  em->start = cur_offset;
1301  em->orig_start = em->start;
1302  em->len = num_bytes;
1303  em->block_len = num_bytes;
1304  em->block_start = disk_bytenr;
1305  em->bdev = root->fs_info->fs_devices->latest_bdev;
1308  while (1) {
1309  write_lock(&em_tree->lock);
1310  ret = add_extent_mapping(em_tree, em);
1311  write_unlock(&em_tree->lock);
1312  if (ret != -EEXIST) {
1313  free_extent_map(em);
1314  break;
1315  }
1316  btrfs_drop_extent_cache(inode, em->start,
1317  em->start + em->len - 1, 0);
1318  }
1319  type = BTRFS_ORDERED_PREALLOC;
1320  } else {
1321  type = BTRFS_ORDERED_NOCOW;
1322  }
1323 
1324  ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1325  num_bytes, num_bytes, type);
1326  BUG_ON(ret); /* -ENOMEM */
1327 
1328  if (root->root_key.objectid ==
1330  ret = btrfs_reloc_clone_csums(inode, cur_offset,
1331  num_bytes);
1332  if (ret) {
1333  btrfs_abort_transaction(trans, root, ret);
1334  goto error;
1335  }
1336  }
1337 
1338  extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
1339  cur_offset, cur_offset + num_bytes - 1,
1340  locked_page, EXTENT_CLEAR_UNLOCK_PAGE |
1343  cur_offset = extent_end;
1344  if (cur_offset > end)
1345  break;
1346  }
1347  btrfs_release_path(path);
1348 
1349  if (cur_offset <= end && cow_start == (u64)-1) {
1350  cow_start = cur_offset;
1351  cur_offset = end;
1352  }
1353 
1354  if (cow_start != (u64)-1) {
1355  ret = cow_file_range(inode, locked_page, cow_start, end,
1356  page_started, nr_written, 1);
1357  if (ret) {
1358  btrfs_abort_transaction(trans, root, ret);
1359  goto error;
1360  }
1361  }
1362 
1363 error:
1364  err = btrfs_end_transaction(trans, root);
1365  if (!ret)
1366  ret = err;
1367 
1368  if (ret && cur_offset < end)
1370  &BTRFS_I(inode)->io_tree,
1371  cur_offset, end, locked_page,
1378 
1379  btrfs_free_path(path);
1380  return ret;
1381 }
1382 
1383 /*
1384  * extent_io.c call back to do delayed allocation processing
1385  */
1386 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1387  u64 start, u64 end, int *page_started,
1388  unsigned long *nr_written)
1389 {
1390  int ret;
1391  struct btrfs_root *root = BTRFS_I(inode)->root;
1392 
1393  if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) {
1394  ret = run_delalloc_nocow(inode, locked_page, start, end,
1395  page_started, 1, nr_written);
1396  } else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC) {
1397  ret = run_delalloc_nocow(inode, locked_page, start, end,
1398  page_started, 0, nr_written);
1399  } else if (!btrfs_test_opt(root, COMPRESS) &&
1400  !(BTRFS_I(inode)->force_compress) &&
1401  !(BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS)) {
1402  ret = cow_file_range(inode, locked_page, start, end,
1403  page_started, nr_written, 1);
1404  } else {
1406  &BTRFS_I(inode)->runtime_flags);
1407  ret = cow_file_range_async(inode, locked_page, start, end,
1408  page_started, nr_written);
1409  }
1410  return ret;
1411 }
1412 
1413 static void btrfs_split_extent_hook(struct inode *inode,
1414  struct extent_state *orig, u64 split)
1415 {
1416  /* not delalloc, ignore it */
1417  if (!(orig->state & EXTENT_DELALLOC))
1418  return;
1419 
1420  spin_lock(&BTRFS_I(inode)->lock);
1421  BTRFS_I(inode)->outstanding_extents++;
1422  spin_unlock(&BTRFS_I(inode)->lock);
1423 }
1424 
1425 /*
1426  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1427  * extents so we can keep track of new extents that are just merged onto old
1428  * extents, such as when we are doing sequential writes, so we can properly
1429  * account for the metadata space we'll need.
1430  */
1431 static void btrfs_merge_extent_hook(struct inode *inode,
1432  struct extent_state *new,
1433  struct extent_state *other)
1434 {
1435  /* not delalloc, ignore it */
1436  if (!(other->state & EXTENT_DELALLOC))
1437  return;
1438 
1439  spin_lock(&BTRFS_I(inode)->lock);
1440  BTRFS_I(inode)->outstanding_extents--;
1441  spin_unlock(&BTRFS_I(inode)->lock);
1442 }
1443 
1444 /*
1445  * extent_io.c set_bit_hook, used to track delayed allocation
1446  * bytes in this file, and to maintain the list of inodes that
1447  * have pending delalloc work to be done.
1448  */
1449 static void btrfs_set_bit_hook(struct inode *inode,
1450  struct extent_state *state, int *bits)
1451 {
1452 
1453  /*
1454  * set_bit and clear bit hooks normally require _irqsave/restore
1455  * but in this case, we are only testing for the DELALLOC
1456  * bit, which is only set or cleared with irqs on
1457  */
1458  if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1459  struct btrfs_root *root = BTRFS_I(inode)->root;
1460  u64 len = state->end + 1 - state->start;
1461  bool do_list = !btrfs_is_free_space_inode(inode);
1462 
1463  if (*bits & EXTENT_FIRST_DELALLOC) {
1464  *bits &= ~EXTENT_FIRST_DELALLOC;
1465  } else {
1466  spin_lock(&BTRFS_I(inode)->lock);
1467  BTRFS_I(inode)->outstanding_extents++;
1468  spin_unlock(&BTRFS_I(inode)->lock);
1469  }
1470 
1471  spin_lock(&root->fs_info->delalloc_lock);
1472  BTRFS_I(inode)->delalloc_bytes += len;
1473  root->fs_info->delalloc_bytes += len;
1474  if (do_list && list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1475  list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1476  &root->fs_info->delalloc_inodes);
1477  }
1478  spin_unlock(&root->fs_info->delalloc_lock);
1479  }
1480 }
1481 
1482 /*
1483  * extent_io.c clear_bit_hook, see set_bit_hook for why
1484  */
1485 static void btrfs_clear_bit_hook(struct inode *inode,
1486  struct extent_state *state, int *bits)
1487 {
1488  /*
1489  * set_bit and clear bit hooks normally require _irqsave/restore
1490  * but in this case, we are only testing for the DELALLOC
1491  * bit, which is only set or cleared with irqs on
1492  */
1493  if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1494  struct btrfs_root *root = BTRFS_I(inode)->root;
1495  u64 len = state->end + 1 - state->start;
1496  bool do_list = !btrfs_is_free_space_inode(inode);
1497 
1498  if (*bits & EXTENT_FIRST_DELALLOC) {
1499  *bits &= ~EXTENT_FIRST_DELALLOC;
1500  } else if (!(*bits & EXTENT_DO_ACCOUNTING)) {
1501  spin_lock(&BTRFS_I(inode)->lock);
1502  BTRFS_I(inode)->outstanding_extents--;
1503  spin_unlock(&BTRFS_I(inode)->lock);
1504  }
1505 
1506  if (*bits & EXTENT_DO_ACCOUNTING)
1507  btrfs_delalloc_release_metadata(inode, len);
1508 
1509  if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
1510  && do_list)
1511  btrfs_free_reserved_data_space(inode, len);
1512 
1513  spin_lock(&root->fs_info->delalloc_lock);
1514  root->fs_info->delalloc_bytes -= len;
1515  BTRFS_I(inode)->delalloc_bytes -= len;
1516 
1517  if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
1518  !list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1519  list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1520  }
1521  spin_unlock(&root->fs_info->delalloc_lock);
1522  }
1523 }
1524 
1525 /*
1526  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1527  * we don't create bios that span stripes or chunks
1528  */
1529 int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
1530  size_t size, struct bio *bio,
1531  unsigned long bio_flags)
1532 {
1533  struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
1534  struct btrfs_mapping_tree *map_tree;
1535  u64 logical = (u64)bio->bi_sector << 9;
1536  u64 length = 0;
1537  u64 map_length;
1538  int ret;
1539 
1540  if (bio_flags & EXTENT_BIO_COMPRESSED)
1541  return 0;
1542 
1543  length = bio->bi_size;
1544  map_tree = &root->fs_info->mapping_tree;
1545  map_length = length;
1546  ret = btrfs_map_block(map_tree, READ, logical,
1547  &map_length, NULL, 0);
1548  /* Will always return 0 or 1 with map_multi == NULL */
1549  BUG_ON(ret < 0);
1550  if (map_length < length + size)
1551  return 1;
1552  return 0;
1553 }
1554 
1555 /*
1556  * in order to insert checksums into the metadata in large chunks,
1557  * we wait until bio submission time. All the pages in the bio are
1558  * checksummed and sums are attached onto the ordered extent record.
1559  *
1560  * At IO completion time the cums attached on the ordered extent record
1561  * are inserted into the btree
1562  */
1563 static int __btrfs_submit_bio_start(struct inode *inode, int rw,
1564  struct bio *bio, int mirror_num,
1565  unsigned long bio_flags,
1566  u64 bio_offset)
1567 {
1568  struct btrfs_root *root = BTRFS_I(inode)->root;
1569  int ret = 0;
1570 
1571  ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1572  BUG_ON(ret); /* -ENOMEM */
1573  return 0;
1574 }
1575 
1576 /*
1577  * in order to insert checksums into the metadata in large chunks,
1578  * we wait until bio submission time. All the pages in the bio are
1579  * checksummed and sums are attached onto the ordered extent record.
1580  *
1581  * At IO completion time the cums attached on the ordered extent record
1582  * are inserted into the btree
1583  */
1584 static int __btrfs_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
1585  int mirror_num, unsigned long bio_flags,
1586  u64 bio_offset)
1587 {
1588  struct btrfs_root *root = BTRFS_I(inode)->root;
1589  return btrfs_map_bio(root, rw, bio, mirror_num, 1);
1590 }
1591 
1592 /*
1593  * extent_io.c submission hook. This does the right thing for csum calculation
1594  * on write, or reading the csums from the tree before a read
1595  */
1596 static int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
1597  int mirror_num, unsigned long bio_flags,
1598  u64 bio_offset)
1599 {
1600  struct btrfs_root *root = BTRFS_I(inode)->root;
1601  int ret = 0;
1602  int skip_sum;
1603  int metadata = 0;
1604 
1605  skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1606 
1607  if (btrfs_is_free_space_inode(inode))
1608  metadata = 2;
1609 
1610  if (!(rw & REQ_WRITE)) {
1611  ret = btrfs_bio_wq_end_io(root->fs_info, bio, metadata);
1612  if (ret)
1613  return ret;
1614 
1615  if (bio_flags & EXTENT_BIO_COMPRESSED) {
1616  return btrfs_submit_compressed_read(inode, bio,
1617  mirror_num, bio_flags);
1618  } else if (!skip_sum) {
1619  ret = btrfs_lookup_bio_sums(root, inode, bio, NULL);
1620  if (ret)
1621  return ret;
1622  }
1623  goto mapit;
1624  } else if (!skip_sum) {
1625  /* csum items have already been cloned */
1626  if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1627  goto mapit;
1628  /* we're doing a write, do the async checksumming */
1629  return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
1630  inode, rw, bio, mirror_num,
1631  bio_flags, bio_offset,
1632  __btrfs_submit_bio_start,
1633  __btrfs_submit_bio_done);
1634  }
1635 
1636 mapit:
1637  return btrfs_map_bio(root, rw, bio, mirror_num, 0);
1638 }
1639 
1640 /*
1641  * given a list of ordered sums record them in the inode. This happens
1642  * at IO completion time based on sums calculated at bio submission time.
1643  */
1644 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1645  struct inode *inode, u64 file_offset,
1646  struct list_head *list)
1647 {
1648  struct btrfs_ordered_sum *sum;
1649 
1650  list_for_each_entry(sum, list, list) {
1651  btrfs_csum_file_blocks(trans,
1652  BTRFS_I(inode)->root->fs_info->csum_root, sum);
1653  }
1654  return 0;
1655 }
1656 
1657 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
1658  struct extent_state **cached_state)
1659 {
1660  if ((end & (PAGE_CACHE_SIZE - 1)) == 0)
1661  WARN_ON(1);
1662  return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1663  cached_state, GFP_NOFS);
1664 }
1665 
1666 /* see btrfs_writepage_start_hook for details on why this is required */
1668  struct page *page;
1669  struct btrfs_work work;
1670 };
1671 
1672 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1673 {
1674  struct btrfs_writepage_fixup *fixup;
1675  struct btrfs_ordered_extent *ordered;
1676  struct extent_state *cached_state = NULL;
1677  struct page *page;
1678  struct inode *inode;
1679  u64 page_start;
1680  u64 page_end;
1681  int ret;
1682 
1683  fixup = container_of(work, struct btrfs_writepage_fixup, work);
1684  page = fixup->page;
1685 again:
1686  lock_page(page);
1687  if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
1688  ClearPageChecked(page);
1689  goto out_page;
1690  }
1691 
1692  inode = page->mapping->host;
1693  page_start = page_offset(page);
1694  page_end = page_offset(page) + PAGE_CACHE_SIZE - 1;
1695 
1696  lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end, 0,
1697  &cached_state);
1698 
1699  /* already ordered? We're done */
1700  if (PagePrivate2(page))
1701  goto out;
1702 
1703  ordered = btrfs_lookup_ordered_extent(inode, page_start);
1704  if (ordered) {
1705  unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
1706  page_end, &cached_state, GFP_NOFS);
1707  unlock_page(page);
1708  btrfs_start_ordered_extent(inode, ordered, 1);
1709  btrfs_put_ordered_extent(ordered);
1710  goto again;
1711  }
1712 
1714  if (ret) {
1715  mapping_set_error(page->mapping, ret);
1716  end_extent_writepage(page, ret, page_start, page_end);
1717  ClearPageChecked(page);
1718  goto out;
1719  }
1720 
1721  btrfs_set_extent_delalloc(inode, page_start, page_end, &cached_state);
1722  ClearPageChecked(page);
1723  set_page_dirty(page);
1724 out:
1725  unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
1726  &cached_state, GFP_NOFS);
1727 out_page:
1728  unlock_page(page);
1729  page_cache_release(page);
1730  kfree(fixup);
1731 }
1732 
1733 /*
1734  * There are a few paths in the higher layers of the kernel that directly
1735  * set the page dirty bit without asking the filesystem if it is a
1736  * good idea. This causes problems because we want to make sure COW
1737  * properly happens and the data=ordered rules are followed.
1738  *
1739  * In our case any range that doesn't have the ORDERED bit set
1740  * hasn't been properly setup for IO. We kick off an async process
1741  * to fix it up. The async helper will wait for ordered extents, set
1742  * the delalloc bit and make it safe to write the page.
1743  */
1744 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
1745 {
1746  struct inode *inode = page->mapping->host;
1747  struct btrfs_writepage_fixup *fixup;
1748  struct btrfs_root *root = BTRFS_I(inode)->root;
1749 
1750  /* this page is properly in the ordered list */
1751  if (TestClearPagePrivate2(page))
1752  return 0;
1753 
1754  if (PageChecked(page))
1755  return -EAGAIN;
1756 
1757  fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
1758  if (!fixup)
1759  return -EAGAIN;
1760 
1761  SetPageChecked(page);
1762  page_cache_get(page);
1763  fixup->work.func = btrfs_writepage_fixup_worker;
1764  fixup->page = page;
1765  btrfs_queue_worker(&root->fs_info->fixup_workers, &fixup->work);
1766  return -EBUSY;
1767 }
1768 
1769 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
1770  struct inode *inode, u64 file_pos,
1771  u64 disk_bytenr, u64 disk_num_bytes,
1772  u64 num_bytes, u64 ram_bytes,
1774  u16 other_encoding, int extent_type)
1775 {
1776  struct btrfs_root *root = BTRFS_I(inode)->root;
1777  struct btrfs_file_extent_item *fi;
1778  struct btrfs_path *path;
1779  struct extent_buffer *leaf;
1780  struct btrfs_key ins;
1781  int ret;
1782 
1783  path = btrfs_alloc_path();
1784  if (!path)
1785  return -ENOMEM;
1786 
1787  path->leave_spinning = 1;
1788 
1789  /*
1790  * we may be replacing one extent in the tree with another.
1791  * The new extent is pinned in the extent map, and we don't want
1792  * to drop it from the cache until it is completely in the btree.
1793  *
1794  * So, tell btrfs_drop_extents to leave this extent in the cache.
1795  * the caller is expected to unpin it and allow it to be merged
1796  * with the others.
1797  */
1798  ret = btrfs_drop_extents(trans, root, inode, file_pos,
1799  file_pos + num_bytes, 0);
1800  if (ret)
1801  goto out;
1802 
1803  ins.objectid = btrfs_ino(inode);
1804  ins.offset = file_pos;
1805  ins.type = BTRFS_EXTENT_DATA_KEY;
1806  ret = btrfs_insert_empty_item(trans, root, path, &ins, sizeof(*fi));
1807  if (ret)
1808  goto out;
1809  leaf = path->nodes[0];
1810  fi = btrfs_item_ptr(leaf, path->slots[0],
1811  struct btrfs_file_extent_item);
1812  btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1813  btrfs_set_file_extent_type(leaf, fi, extent_type);
1814  btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
1815  btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
1816  btrfs_set_file_extent_offset(leaf, fi, 0);
1817  btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
1818  btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
1819  btrfs_set_file_extent_compression(leaf, fi, compression);
1820  btrfs_set_file_extent_encryption(leaf, fi, encryption);
1821  btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
1822 
1824  btrfs_release_path(path);
1825 
1826  inode_add_bytes(inode, num_bytes);
1827 
1828  ins.objectid = disk_bytenr;
1829  ins.offset = disk_num_bytes;
1830  ins.type = BTRFS_EXTENT_ITEM_KEY;
1831  ret = btrfs_alloc_reserved_file_extent(trans, root,
1832  root->root_key.objectid,
1833  btrfs_ino(inode), file_pos, &ins);
1834 out:
1835  btrfs_free_path(path);
1836 
1837  return ret;
1838 }
1839 
1840 /*
1841  * helper function for btrfs_finish_ordered_io, this
1842  * just reads in some of the csum leaves to prime them into ram
1843  * before we start the transaction. It limits the amount of btree
1844  * reads required while inside the transaction.
1845  */
1846 /* as ordered data IO finishes, this gets called so we can finish
1847  * an ordered extent if the range of bytes in the file it covers are
1848  * fully written.
1849  */
1850 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
1851 {
1852  struct inode *inode = ordered_extent->inode;
1853  struct btrfs_root *root = BTRFS_I(inode)->root;
1854  struct btrfs_trans_handle *trans = NULL;
1855  struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1856  struct extent_state *cached_state = NULL;
1857  int compress_type = 0;
1858  int ret;
1859  bool nolock;
1860 
1861  nolock = btrfs_is_free_space_inode(inode);
1862 
1863  if (test_bit(BTRFS_ORDERED_IOERR, &ordered_extent->flags)) {
1864  ret = -EIO;
1865  goto out;
1866  }
1867 
1868  if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
1869  BUG_ON(!list_empty(&ordered_extent->list)); /* Logic error */
1870  ret = btrfs_ordered_update_i_size(inode, 0, ordered_extent);
1871  if (!ret) {
1872  if (nolock)
1873  trans = btrfs_join_transaction_nolock(root);
1874  else
1875  trans = btrfs_join_transaction(root);
1876  if (IS_ERR(trans)) {
1877  ret = PTR_ERR(trans);
1878  trans = NULL;
1879  goto out;
1880  }
1881  trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1882  ret = btrfs_update_inode_fallback(trans, root, inode);
1883  if (ret) /* -ENOMEM or corruption */
1884  btrfs_abort_transaction(trans, root, ret);
1885  }
1886  goto out;
1887  }
1888 
1889  lock_extent_bits(io_tree, ordered_extent->file_offset,
1890  ordered_extent->file_offset + ordered_extent->len - 1,
1891  0, &cached_state);
1892 
1893  if (nolock)
1894  trans = btrfs_join_transaction_nolock(root);
1895  else
1896  trans = btrfs_join_transaction(root);
1897  if (IS_ERR(trans)) {
1898  ret = PTR_ERR(trans);
1899  trans = NULL;
1900  goto out_unlock;
1901  }
1902  trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1903 
1904  if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
1905  compress_type = ordered_extent->compress_type;
1906  if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
1907  BUG_ON(compress_type);
1908  ret = btrfs_mark_extent_written(trans, inode,
1909  ordered_extent->file_offset,
1910  ordered_extent->file_offset +
1911  ordered_extent->len);
1912  } else {
1913  BUG_ON(root == root->fs_info->tree_root);
1914  ret = insert_reserved_file_extent(trans, inode,
1915  ordered_extent->file_offset,
1916  ordered_extent->start,
1917  ordered_extent->disk_len,
1918  ordered_extent->len,
1919  ordered_extent->len,
1920  compress_type, 0, 0,
1922  }
1923  unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
1924  ordered_extent->file_offset, ordered_extent->len,
1925  trans->transid);
1926  if (ret < 0) {
1927  btrfs_abort_transaction(trans, root, ret);
1928  goto out_unlock;
1929  }
1930 
1931  add_pending_csums(trans, inode, ordered_extent->file_offset,
1932  &ordered_extent->list);
1933 
1934  ret = btrfs_ordered_update_i_size(inode, 0, ordered_extent);
1935  if (!ret || !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
1936  ret = btrfs_update_inode_fallback(trans, root, inode);
1937  if (ret) { /* -ENOMEM or corruption */
1938  btrfs_abort_transaction(trans, root, ret);
1939  goto out_unlock;
1940  }
1941  } else {
1942  btrfs_set_inode_last_trans(trans, inode);
1943  }
1944  ret = 0;
1945 out_unlock:
1946  unlock_extent_cached(io_tree, ordered_extent->file_offset,
1947  ordered_extent->file_offset +
1948  ordered_extent->len - 1, &cached_state, GFP_NOFS);
1949 out:
1950  if (root != root->fs_info->tree_root)
1951  btrfs_delalloc_release_metadata(inode, ordered_extent->len);
1952  if (trans)
1953  btrfs_end_transaction(trans, root);
1954 
1955  if (ret)
1956  clear_extent_uptodate(io_tree, ordered_extent->file_offset,
1957  ordered_extent->file_offset +
1958  ordered_extent->len - 1, NULL, GFP_NOFS);
1959 
1960  /*
1961  * This needs to be done to make sure anybody waiting knows we are done
1962  * updating everything for this ordered extent.
1963  */
1964  btrfs_remove_ordered_extent(inode, ordered_extent);
1965 
1966  /* once for us */
1967  btrfs_put_ordered_extent(ordered_extent);
1968  /* once for the tree */
1969  btrfs_put_ordered_extent(ordered_extent);
1970 
1971  return ret;
1972 }
1973 
1974 static void finish_ordered_fn(struct btrfs_work *work)
1975 {
1976  struct btrfs_ordered_extent *ordered_extent;
1977  ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
1978  btrfs_finish_ordered_io(ordered_extent);
1979 }
1980 
1981 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
1982  struct extent_state *state, int uptodate)
1983 {
1984  struct inode *inode = page->mapping->host;
1985  struct btrfs_root *root = BTRFS_I(inode)->root;
1986  struct btrfs_ordered_extent *ordered_extent = NULL;
1987  struct btrfs_workers *workers;
1988 
1989  trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
1990 
1991  ClearPagePrivate2(page);
1992  if (!btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
1993  end - start + 1, uptodate))
1994  return 0;
1995 
1996  ordered_extent->work.func = finish_ordered_fn;
1997  ordered_extent->work.flags = 0;
1998 
1999  if (btrfs_is_free_space_inode(inode))
2000  workers = &root->fs_info->endio_freespace_worker;
2001  else
2002  workers = &root->fs_info->endio_write_workers;
2003  btrfs_queue_worker(workers, &ordered_extent->work);
2004 
2005  return 0;
2006 }
2007 
2008 /*
2009  * when reads are done, we need to check csums to verify the data is correct
2010  * if there's a match, we allow the bio to finish. If not, the code in
2011  * extent_io.c will try to find good copies for us.
2012  */
2013 static int btrfs_readpage_end_io_hook(struct page *page, u64 start, u64 end,
2014  struct extent_state *state, int mirror)
2015 {
2016  size_t offset = start - ((u64)page->index << PAGE_CACHE_SHIFT);
2017  struct inode *inode = page->mapping->host;
2018  struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2019  char *kaddr;
2020  u64 private = ~(u32)0;
2021  int ret;
2022  struct btrfs_root *root = BTRFS_I(inode)->root;
2023  u32 csum = ~(u32)0;
2024 
2025  if (PageChecked(page)) {
2026  ClearPageChecked(page);
2027  goto good;
2028  }
2029 
2030  if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
2031  goto good;
2032 
2033  if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
2034  test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
2035  clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
2036  GFP_NOFS);
2037  return 0;
2038  }
2039 
2040  if (state && state->start == start) {
2041  private = state->private;
2042  ret = 0;
2043  } else {
2044  ret = get_state_private(io_tree, start, &private);
2045  }
2046  kaddr = kmap_atomic(page);
2047  if (ret)
2048  goto zeroit;
2049 
2050  csum = btrfs_csum_data(root, kaddr + offset, csum, end - start + 1);
2051  btrfs_csum_final(csum, (char *)&csum);
2052  if (csum != private)
2053  goto zeroit;
2054 
2055  kunmap_atomic(kaddr);
2056 good:
2057  return 0;
2058 
2059 zeroit:
2060  printk_ratelimited(KERN_INFO "btrfs csum failed ino %llu off %llu csum %u "
2061  "private %llu\n",
2062  (unsigned long long)btrfs_ino(page->mapping->host),
2063  (unsigned long long)start, csum,
2064  (unsigned long long)private);
2065  memset(kaddr + offset, 1, end - start + 1);
2066  flush_dcache_page(page);
2067  kunmap_atomic(kaddr);
2068  if (private == 0)
2069  return 0;
2070  return -EIO;
2071 }
2072 
2074  struct list_head list;
2075  struct inode *inode;
2076 };
2077 
2078 /* JDM: If this is fs-wide, why can't we add a pointer to
2079  * btrfs_inode instead and avoid the allocation? */
2080 void btrfs_add_delayed_iput(struct inode *inode)
2081 {
2082  struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2083  struct delayed_iput *delayed;
2084 
2085  if (atomic_add_unless(&inode->i_count, -1, 1))
2086  return;
2087 
2088  delayed = kmalloc(sizeof(*delayed), GFP_NOFS | __GFP_NOFAIL);
2089  delayed->inode = inode;
2090 
2091  spin_lock(&fs_info->delayed_iput_lock);
2092  list_add_tail(&delayed->list, &fs_info->delayed_iputs);
2093  spin_unlock(&fs_info->delayed_iput_lock);
2094 }
2095 
2097 {
2098  LIST_HEAD(list);
2099  struct btrfs_fs_info *fs_info = root->fs_info;
2100  struct delayed_iput *delayed;
2101  int empty;
2102 
2103  spin_lock(&fs_info->delayed_iput_lock);
2104  empty = list_empty(&fs_info->delayed_iputs);
2105  spin_unlock(&fs_info->delayed_iput_lock);
2106  if (empty)
2107  return;
2108 
2109  spin_lock(&fs_info->delayed_iput_lock);
2110  list_splice_init(&fs_info->delayed_iputs, &list);
2111  spin_unlock(&fs_info->delayed_iput_lock);
2112 
2113  while (!list_empty(&list)) {
2114  delayed = list_entry(list.next, struct delayed_iput, list);
2115  list_del(&delayed->list);
2116  iput(delayed->inode);
2117  kfree(delayed);
2118  }
2119 }
2120 
2124 };
2125 
2126 /*
2127  * This is called in transaction commit time. If there are no orphan
2128  * files in the subvolume, it removes orphan item and frees block_rsv
2129  * structure.
2130  */
2132  struct btrfs_root *root)
2133 {
2134  struct btrfs_block_rsv *block_rsv;
2135  int ret;
2136 
2137  if (atomic_read(&root->orphan_inodes) ||
2139  return;
2140 
2141  spin_lock(&root->orphan_lock);
2142  if (atomic_read(&root->orphan_inodes)) {
2143  spin_unlock(&root->orphan_lock);
2144  return;
2145  }
2146 
2148  spin_unlock(&root->orphan_lock);
2149  return;
2150  }
2151 
2152  block_rsv = root->orphan_block_rsv;
2153  root->orphan_block_rsv = NULL;
2154  spin_unlock(&root->orphan_lock);
2155 
2156  if (root->orphan_item_inserted &&
2157  btrfs_root_refs(&root->root_item) > 0) {
2158  ret = btrfs_del_orphan_item(trans, root->fs_info->tree_root,
2159  root->root_key.objectid);
2160  BUG_ON(ret);
2161  root->orphan_item_inserted = 0;
2162  }
2163 
2164  if (block_rsv) {
2165  WARN_ON(block_rsv->size > 0);
2166  btrfs_free_block_rsv(root, block_rsv);
2167  }
2168 }
2169 
2170 /*
2171  * This creates an orphan entry for the given inode in case something goes
2172  * wrong in the middle of an unlink/truncate.
2173  *
2174  * NOTE: caller of this function should reserve 5 units of metadata for
2175  * this function.
2176  */
2177 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
2178 {
2179  struct btrfs_root *root = BTRFS_I(inode)->root;
2180  struct btrfs_block_rsv *block_rsv = NULL;
2181  int reserve = 0;
2182  int insert = 0;
2183  int ret;
2184 
2185  if (!root->orphan_block_rsv) {
2186  block_rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
2187  if (!block_rsv)
2188  return -ENOMEM;
2189  }
2190 
2191  spin_lock(&root->orphan_lock);
2192  if (!root->orphan_block_rsv) {
2193  root->orphan_block_rsv = block_rsv;
2194  } else if (block_rsv) {
2195  btrfs_free_block_rsv(root, block_rsv);
2196  block_rsv = NULL;
2197  }
2198 
2200  &BTRFS_I(inode)->runtime_flags)) {
2201 #if 0
2202  /*
2203  * For proper ENOSPC handling, we should do orphan
2204  * cleanup when mounting. But this introduces backward
2205  * compatibility issue.
2206  */
2207  if (!xchg(&root->orphan_item_inserted, 1))
2208  insert = 2;
2209  else
2210  insert = 1;
2211 #endif
2212  insert = 1;
2213  atomic_inc(&root->orphan_inodes);
2214  }
2215 
2217  &BTRFS_I(inode)->runtime_flags))
2218  reserve = 1;
2219  spin_unlock(&root->orphan_lock);
2220 
2221  /* grab metadata reservation from transaction handle */
2222  if (reserve) {
2223  ret = btrfs_orphan_reserve_metadata(trans, inode);
2224  BUG_ON(ret); /* -ENOSPC in reservation; Logic error? JDM */
2225  }
2226 
2227  /* insert an orphan item to track this unlinked/truncated file */
2228  if (insert >= 1) {
2229  ret = btrfs_insert_orphan_item(trans, root, btrfs_ino(inode));
2230  if (ret && ret != -EEXIST) {
2232  &BTRFS_I(inode)->runtime_flags);
2233  btrfs_abort_transaction(trans, root, ret);
2234  return ret;
2235  }
2236  ret = 0;
2237  }
2238 
2239  /* insert an orphan item to track subvolume contains orphan files */
2240  if (insert >= 2) {
2241  ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
2242  root->root_key.objectid);
2243  if (ret && ret != -EEXIST) {
2244  btrfs_abort_transaction(trans, root, ret);
2245  return ret;
2246  }
2247  }
2248  return 0;
2249 }
2250 
2251 /*
2252  * We have done the truncate/delete so we can go ahead and remove the orphan
2253  * item for this particular inode.
2254  */
2255 int btrfs_orphan_del(struct btrfs_trans_handle *trans, struct inode *inode)
2256 {
2257  struct btrfs_root *root = BTRFS_I(inode)->root;
2258  int delete_item = 0;
2259  int release_rsv = 0;
2260  int ret = 0;
2261 
2262  spin_lock(&root->orphan_lock);
2264  &BTRFS_I(inode)->runtime_flags))
2265  delete_item = 1;
2266 
2268  &BTRFS_I(inode)->runtime_flags))
2269  release_rsv = 1;
2270  spin_unlock(&root->orphan_lock);
2271 
2272  if (trans && delete_item) {
2273  ret = btrfs_del_orphan_item(trans, root, btrfs_ino(inode));
2274  BUG_ON(ret); /* -ENOMEM or corruption (JDM: Recheck) */
2275  }
2276 
2277  if (release_rsv) {
2279  atomic_dec(&root->orphan_inodes);
2280  }
2281 
2282  return 0;
2283 }
2284 
2285 /*
2286  * this cleans up any orphans that may be left on the list from the last use
2287  * of this root.
2288  */
2290 {
2291  struct btrfs_path *path;
2292  struct extent_buffer *leaf;
2293  struct btrfs_key key, found_key;
2294  struct btrfs_trans_handle *trans;
2295  struct inode *inode;
2296  u64 last_objectid = 0;
2297  int ret = 0, nr_unlink = 0, nr_truncate = 0;
2298 
2300  return 0;
2301 
2302  path = btrfs_alloc_path();
2303  if (!path) {
2304  ret = -ENOMEM;
2305  goto out;
2306  }
2307  path->reada = -1;
2308 
2310  btrfs_set_key_type(&key, BTRFS_ORPHAN_ITEM_KEY);
2311  key.offset = (u64)-1;
2312 
2313  while (1) {
2314  ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2315  if (ret < 0)
2316  goto out;
2317 
2318  /*
2319  * if ret == 0 means we found what we were searching for, which
2320  * is weird, but possible, so only screw with path if we didn't
2321  * find the key and see if we have stuff that matches
2322  */
2323  if (ret > 0) {
2324  ret = 0;
2325  if (path->slots[0] == 0)
2326  break;
2327  path->slots[0]--;
2328  }
2329 
2330  /* pull out the item */
2331  leaf = path->nodes[0];
2332  btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2333 
2334  /* make sure the item matches what we want */
2335  if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
2336  break;
2337  if (btrfs_key_type(&found_key) != BTRFS_ORPHAN_ITEM_KEY)
2338  break;
2339 
2340  /* release the path since we're done with it */
2341  btrfs_release_path(path);
2342 
2343  /*
2344  * this is where we are basically btrfs_lookup, without the
2345  * crossing root thing. we store the inode number in the
2346  * offset of the orphan item.
2347  */
2348 
2349  if (found_key.offset == last_objectid) {
2350  printk(KERN_ERR "btrfs: Error removing orphan entry, "
2351  "stopping orphan cleanup\n");
2352  ret = -EINVAL;
2353  goto out;
2354  }
2355 
2356  last_objectid = found_key.offset;
2357 
2358  found_key.objectid = found_key.offset;
2359  found_key.type = BTRFS_INODE_ITEM_KEY;
2360  found_key.offset = 0;
2361  inode = btrfs_iget(root->fs_info->sb, &found_key, root, NULL);
2362  ret = PTR_RET(inode);
2363  if (ret && ret != -ESTALE)
2364  goto out;
2365 
2366  if (ret == -ESTALE && root == root->fs_info->tree_root) {
2367  struct btrfs_root *dead_root;
2368  struct btrfs_fs_info *fs_info = root->fs_info;
2369  int is_dead_root = 0;
2370 
2371  /*
2372  * this is an orphan in the tree root. Currently these
2373  * could come from 2 sources:
2374  * a) a snapshot deletion in progress
2375  * b) a free space cache inode
2376  * We need to distinguish those two, as the snapshot
2377  * orphan must not get deleted.
2378  * find_dead_roots already ran before us, so if this
2379  * is a snapshot deletion, we should find the root
2380  * in the dead_roots list
2381  */
2382  spin_lock(&fs_info->trans_lock);
2383  list_for_each_entry(dead_root, &fs_info->dead_roots,
2384  root_list) {
2385  if (dead_root->root_key.objectid ==
2386  found_key.objectid) {
2387  is_dead_root = 1;
2388  break;
2389  }
2390  }
2391  spin_unlock(&fs_info->trans_lock);
2392  if (is_dead_root) {
2393  /* prevent this orphan from being found again */
2394  key.offset = found_key.objectid - 1;
2395  continue;
2396  }
2397  }
2398  /*
2399  * Inode is already gone but the orphan item is still there,
2400  * kill the orphan item.
2401  */
2402  if (ret == -ESTALE) {
2403  trans = btrfs_start_transaction(root, 1);
2404  if (IS_ERR(trans)) {
2405  ret = PTR_ERR(trans);
2406  goto out;
2407  }
2408  printk(KERN_ERR "auto deleting %Lu\n",
2409  found_key.objectid);
2410  ret = btrfs_del_orphan_item(trans, root,
2411  found_key.objectid);
2412  BUG_ON(ret); /* -ENOMEM or corruption (JDM: Recheck) */
2413  btrfs_end_transaction(trans, root);
2414  continue;
2415  }
2416 
2417  /*
2418  * add this inode to the orphan list so btrfs_orphan_del does
2419  * the proper thing when we hit it
2420  */
2422  &BTRFS_I(inode)->runtime_flags);
2423 
2424  /* if we have links, this was a truncate, lets do that */
2425  if (inode->i_nlink) {
2426  if (!S_ISREG(inode->i_mode)) {
2427  WARN_ON(1);
2428  iput(inode);
2429  continue;
2430  }
2431  nr_truncate++;
2432  ret = btrfs_truncate(inode);
2433  } else {
2434  nr_unlink++;
2435  }
2436 
2437  /* this will do delete_inode and everything for us */
2438  iput(inode);
2439  if (ret)
2440  goto out;
2441  }
2442  /* release the path since we're done with it */
2443  btrfs_release_path(path);
2444 
2446 
2447  if (root->orphan_block_rsv)
2449  (u64)-1);
2450 
2451  if (root->orphan_block_rsv || root->orphan_item_inserted) {
2452  trans = btrfs_join_transaction(root);
2453  if (!IS_ERR(trans))
2454  btrfs_end_transaction(trans, root);
2455  }
2456 
2457  if (nr_unlink)
2458  printk(KERN_INFO "btrfs: unlinked %d orphans\n", nr_unlink);
2459  if (nr_truncate)
2460  printk(KERN_INFO "btrfs: truncated %d orphans\n", nr_truncate);
2461 
2462 out:
2463  if (ret)
2464  printk(KERN_CRIT "btrfs: could not do orphan cleanup %d\n", ret);
2465  btrfs_free_path(path);
2466  return ret;
2467 }
2468 
2469 /*
2470  * very simple check to peek ahead in the leaf looking for xattrs. If we
2471  * don't find any xattrs, we know there can't be any acls.
2472  *
2473  * slot is the slot the inode is in, objectid is the objectid of the inode
2474  */
2475 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
2476  int slot, u64 objectid)
2477 {
2478  u32 nritems = btrfs_header_nritems(leaf);
2479  struct btrfs_key found_key;
2480  int scanned = 0;
2481 
2482  slot++;
2483  while (slot < nritems) {
2484  btrfs_item_key_to_cpu(leaf, &found_key, slot);
2485 
2486  /* we found a different objectid, there must not be acls */
2487  if (found_key.objectid != objectid)
2488  return 0;
2489 
2490  /* we found an xattr, assume we've got an acl */
2491  if (found_key.type == BTRFS_XATTR_ITEM_KEY)
2492  return 1;
2493 
2494  /*
2495  * we found a key greater than an xattr key, there can't
2496  * be any acls later on
2497  */
2498  if (found_key.type > BTRFS_XATTR_ITEM_KEY)
2499  return 0;
2500 
2501  slot++;
2502  scanned++;
2503 
2504  /*
2505  * it goes inode, inode backrefs, xattrs, extents,
2506  * so if there are a ton of hard links to an inode there can
2507  * be a lot of backrefs. Don't waste time searching too hard,
2508  * this is just an optimization
2509  */
2510  if (scanned >= 8)
2511  break;
2512  }
2513  /* we hit the end of the leaf before we found an xattr or
2514  * something larger than an xattr. We have to assume the inode
2515  * has acls
2516  */
2517  return 1;
2518 }
2519 
2520 /*
2521  * read an inode from the btree into the in-memory inode
2522  */
2523 static void btrfs_read_locked_inode(struct inode *inode)
2524 {
2525  struct btrfs_path *path;
2526  struct extent_buffer *leaf;
2527  struct btrfs_inode_item *inode_item;
2528  struct btrfs_timespec *tspec;
2529  struct btrfs_root *root = BTRFS_I(inode)->root;
2530  struct btrfs_key location;
2531  int maybe_acls;
2532  u32 rdev;
2533  int ret;
2534  bool filled = false;
2535 
2536  ret = btrfs_fill_inode(inode, &rdev);
2537  if (!ret)
2538  filled = true;
2539 
2540  path = btrfs_alloc_path();
2541  if (!path)
2542  goto make_bad;
2543 
2544  path->leave_spinning = 1;
2545  memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
2546 
2547  ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
2548  if (ret)
2549  goto make_bad;
2550 
2551  leaf = path->nodes[0];
2552 
2553  if (filled)
2554  goto cache_acl;
2555 
2556  inode_item = btrfs_item_ptr(leaf, path->slots[0],
2557  struct btrfs_inode_item);
2558  inode->i_mode = btrfs_inode_mode(leaf, inode_item);
2559  set_nlink(inode, btrfs_inode_nlink(leaf, inode_item));
2560  i_uid_write(inode, btrfs_inode_uid(leaf, inode_item));
2561  i_gid_write(inode, btrfs_inode_gid(leaf, inode_item));
2562  btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
2563 
2564  tspec = btrfs_inode_atime(inode_item);
2565  inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2566  inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2567 
2568  tspec = btrfs_inode_mtime(inode_item);
2569  inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2570  inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2571 
2572  tspec = btrfs_inode_ctime(inode_item);
2573  inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2574  inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2575 
2576  inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
2577  BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
2578  BTRFS_I(inode)->last_trans = btrfs_inode_transid(leaf, inode_item);
2579 
2580  /*
2581  * If we were modified in the current generation and evicted from memory
2582  * and then re-read we need to do a full sync since we don't have any
2583  * idea about which extents were modified before we were evicted from
2584  * cache.
2585  */
2586  if (BTRFS_I(inode)->last_trans == root->fs_info->generation)
2588  &BTRFS_I(inode)->runtime_flags);
2589 
2590  inode->i_version = btrfs_inode_sequence(leaf, inode_item);
2591  inode->i_generation = BTRFS_I(inode)->generation;
2592  inode->i_rdev = 0;
2593  rdev = btrfs_inode_rdev(leaf, inode_item);
2594 
2595  BTRFS_I(inode)->index_cnt = (u64)-1;
2596  BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
2597 cache_acl:
2598  /*
2599  * try to precache a NULL acl entry for files that don't have
2600  * any xattrs or acls
2601  */
2602  maybe_acls = acls_after_inode_item(leaf, path->slots[0],
2603  btrfs_ino(inode));
2604  if (!maybe_acls)
2605  cache_no_acl(inode);
2606 
2607  btrfs_free_path(path);
2608 
2609  switch (inode->i_mode & S_IFMT) {
2610  case S_IFREG:
2611  inode->i_mapping->a_ops = &btrfs_aops;
2612  inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
2613  BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
2614  inode->i_fop = &btrfs_file_operations;
2615  inode->i_op = &btrfs_file_inode_operations;
2616  break;
2617  case S_IFDIR:
2618  inode->i_fop = &btrfs_dir_file_operations;
2619  if (root == root->fs_info->tree_root)
2620  inode->i_op = &btrfs_dir_ro_inode_operations;
2621  else
2622  inode->i_op = &btrfs_dir_inode_operations;
2623  break;
2624  case S_IFLNK:
2625  inode->i_op = &btrfs_symlink_inode_operations;
2626  inode->i_mapping->a_ops = &btrfs_symlink_aops;
2627  inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
2628  break;
2629  default:
2630  inode->i_op = &btrfs_special_inode_operations;
2631  init_special_inode(inode, inode->i_mode, rdev);
2632  break;
2633  }
2634 
2635  btrfs_update_iflags(inode);
2636  return;
2637 
2638 make_bad:
2639  btrfs_free_path(path);
2640  make_bad_inode(inode);
2641 }
2642 
2643 /*
2644  * given a leaf and an inode, copy the inode fields into the leaf
2645  */
2646 static void fill_inode_item(struct btrfs_trans_handle *trans,
2647  struct extent_buffer *leaf,
2648  struct btrfs_inode_item *item,
2649  struct inode *inode)
2650 {
2651  btrfs_set_inode_uid(leaf, item, i_uid_read(inode));
2652  btrfs_set_inode_gid(leaf, item, i_gid_read(inode));
2653  btrfs_set_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size);
2654  btrfs_set_inode_mode(leaf, item, inode->i_mode);
2655  btrfs_set_inode_nlink(leaf, item, inode->i_nlink);
2656 
2657  btrfs_set_timespec_sec(leaf, btrfs_inode_atime(item),
2658  inode->i_atime.tv_sec);
2659  btrfs_set_timespec_nsec(leaf, btrfs_inode_atime(item),
2660  inode->i_atime.tv_nsec);
2661 
2662  btrfs_set_timespec_sec(leaf, btrfs_inode_mtime(item),
2663  inode->i_mtime.tv_sec);
2664  btrfs_set_timespec_nsec(leaf, btrfs_inode_mtime(item),
2665  inode->i_mtime.tv_nsec);
2666 
2667  btrfs_set_timespec_sec(leaf, btrfs_inode_ctime(item),
2668  inode->i_ctime.tv_sec);
2669  btrfs_set_timespec_nsec(leaf, btrfs_inode_ctime(item),
2670  inode->i_ctime.tv_nsec);
2671 
2672  btrfs_set_inode_nbytes(leaf, item, inode_get_bytes(inode));
2673  btrfs_set_inode_generation(leaf, item, BTRFS_I(inode)->generation);
2674  btrfs_set_inode_sequence(leaf, item, inode->i_version);
2675  btrfs_set_inode_transid(leaf, item, trans->transid);
2676  btrfs_set_inode_rdev(leaf, item, inode->i_rdev);
2677  btrfs_set_inode_flags(leaf, item, BTRFS_I(inode)->flags);
2678  btrfs_set_inode_block_group(leaf, item, 0);
2679 }
2680 
2681 /*
2682  * copy everything in the in-memory inode into the btree.
2683  */
2684 static noinline int btrfs_update_inode_item(struct btrfs_trans_handle *trans,
2685  struct btrfs_root *root, struct inode *inode)
2686 {
2687  struct btrfs_inode_item *inode_item;
2688  struct btrfs_path *path;
2689  struct extent_buffer *leaf;
2690  int ret;
2691 
2692  path = btrfs_alloc_path();
2693  if (!path)
2694  return -ENOMEM;
2695 
2696  path->leave_spinning = 1;
2697  ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
2698  1);
2699  if (ret) {
2700  if (ret > 0)
2701  ret = -ENOENT;
2702  goto failed;
2703  }
2704 
2705  btrfs_unlock_up_safe(path, 1);
2706  leaf = path->nodes[0];
2707  inode_item = btrfs_item_ptr(leaf, path->slots[0],
2708  struct btrfs_inode_item);
2709 
2710  fill_inode_item(trans, leaf, inode_item, inode);
2712  btrfs_set_inode_last_trans(trans, inode);
2713  ret = 0;
2714 failed:
2715  btrfs_free_path(path);
2716  return ret;
2717 }
2718 
2719 /*
2720  * copy everything in the in-memory inode into the btree.
2721  */
2723  struct btrfs_root *root, struct inode *inode)
2724 {
2725  int ret;
2726 
2727  /*
2728  * If the inode is a free space inode, we can deadlock during commit
2729  * if we put it into the delayed code.
2730  *
2731  * The data relocation inode should also be directly updated
2732  * without delay
2733  */
2734  if (!btrfs_is_free_space_inode(inode)
2735  && root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID) {
2736  btrfs_update_root_times(trans, root);
2737 
2738  ret = btrfs_delayed_update_inode(trans, root, inode);
2739  if (!ret)
2740  btrfs_set_inode_last_trans(trans, inode);
2741  return ret;
2742  }
2743 
2744  return btrfs_update_inode_item(trans, root, inode);
2745 }
2746 
2748  struct btrfs_root *root,
2749  struct inode *inode)
2750 {
2751  int ret;
2752 
2753  ret = btrfs_update_inode(trans, root, inode);
2754  if (ret == -ENOSPC)
2755  return btrfs_update_inode_item(trans, root, inode);
2756  return ret;
2757 }
2758 
2759 /*
2760  * unlink helper that gets used here in inode.c and in the tree logging
2761  * recovery code. It remove a link in a directory with a given name, and
2762  * also drops the back refs in the inode to the directory
2763  */
2764 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
2765  struct btrfs_root *root,
2766  struct inode *dir, struct inode *inode,
2767  const char *name, int name_len)
2768 {
2769  struct btrfs_path *path;
2770  int ret = 0;
2771  struct extent_buffer *leaf;
2772  struct btrfs_dir_item *di;
2773  struct btrfs_key key;
2774  u64 index;
2775  u64 ino = btrfs_ino(inode);
2776  u64 dir_ino = btrfs_ino(dir);
2777 
2778  path = btrfs_alloc_path();
2779  if (!path) {
2780  ret = -ENOMEM;
2781  goto out;
2782  }
2783 
2784  path->leave_spinning = 1;
2785  di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
2786  name, name_len, -1);
2787  if (IS_ERR(di)) {
2788  ret = PTR_ERR(di);
2789  goto err;
2790  }
2791  if (!di) {
2792  ret = -ENOENT;
2793  goto err;
2794  }
2795  leaf = path->nodes[0];
2796  btrfs_dir_item_key_to_cpu(leaf, di, &key);
2797  ret = btrfs_delete_one_dir_name(trans, root, path, di);
2798  if (ret)
2799  goto err;
2800  btrfs_release_path(path);
2801 
2802  ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
2803  dir_ino, &index);
2804  if (ret) {
2805  printk(KERN_INFO "btrfs failed to delete reference to %.*s, "
2806  "inode %llu parent %llu\n", name_len, name,
2807  (unsigned long long)ino, (unsigned long long)dir_ino);
2808  btrfs_abort_transaction(trans, root, ret);
2809  goto err;
2810  }
2811 
2812  ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
2813  if (ret) {
2814  btrfs_abort_transaction(trans, root, ret);
2815  goto err;
2816  }
2817 
2818  ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
2819  inode, dir_ino);
2820  if (ret != 0 && ret != -ENOENT) {
2821  btrfs_abort_transaction(trans, root, ret);
2822  goto err;
2823  }
2824 
2825  ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
2826  dir, index);
2827  if (ret == -ENOENT)
2828  ret = 0;
2829 err:
2830  btrfs_free_path(path);
2831  if (ret)
2832  goto out;
2833 
2834  btrfs_i_size_write(dir, dir->i_size - name_len * 2);
2835  inode_inc_iversion(inode);
2836  inode_inc_iversion(dir);
2837  inode->i_ctime = dir->i_mtime = dir->i_ctime = CURRENT_TIME;
2838  ret = btrfs_update_inode(trans, root, dir);
2839 out:
2840  return ret;
2841 }
2842 
2844  struct btrfs_root *root,
2845  struct inode *dir, struct inode *inode,
2846  const char *name, int name_len)
2847 {
2848  int ret;
2849  ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
2850  if (!ret) {
2851  btrfs_drop_nlink(inode);
2852  ret = btrfs_update_inode(trans, root, inode);
2853  }
2854  return ret;
2855 }
2856 
2857 
2858 /* helper to check if there is any shared block in the path */
2859 static int check_path_shared(struct btrfs_root *root,
2860  struct btrfs_path *path)
2861 {
2862  struct extent_buffer *eb;
2863  int level;
2864  u64 refs = 1;
2865 
2866  for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2867  int ret;
2868 
2869  if (!path->nodes[level])
2870  break;
2871  eb = path->nodes[level];
2872  if (!btrfs_block_can_be_shared(root, eb))
2873  continue;
2874  ret = btrfs_lookup_extent_info(NULL, root, eb->start, eb->len,
2875  &refs, NULL);
2876  if (refs > 1)
2877  return 1;
2878  }
2879  return 0;
2880 }
2881 
2882 /*
2883  * helper to start transaction for unlink and rmdir.
2884  *
2885  * unlink and rmdir are special in btrfs, they do not always free space.
2886  * so in enospc case, we should make sure they will free space before
2887  * allowing them to use the global metadata reservation.
2888  */
2889 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir,
2890  struct dentry *dentry)
2891 {
2892  struct btrfs_trans_handle *trans;
2893  struct btrfs_root *root = BTRFS_I(dir)->root;
2894  struct btrfs_path *path;
2895  struct btrfs_dir_item *di;
2896  struct inode *inode = dentry->d_inode;
2897  u64 index;
2898  int check_link = 1;
2899  int err = -ENOSPC;
2900  int ret;
2901  u64 ino = btrfs_ino(inode);
2902  u64 dir_ino = btrfs_ino(dir);
2903 
2904  /*
2905  * 1 for the possible orphan item
2906  * 1 for the dir item
2907  * 1 for the dir index
2908  * 1 for the inode ref
2909  * 1 for the inode ref in the tree log
2910  * 2 for the dir entries in the log
2911  * 1 for the inode
2912  */
2913  trans = btrfs_start_transaction(root, 8);
2914  if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
2915  return trans;
2916 
2918  return ERR_PTR(-ENOSPC);
2919 
2920  /* check if there is someone else holds reference */
2921  if (S_ISDIR(inode->i_mode) && atomic_read(&inode->i_count) > 1)
2922  return ERR_PTR(-ENOSPC);
2923 
2924  if (atomic_read(&inode->i_count) > 2)
2925  return ERR_PTR(-ENOSPC);
2926 
2927  if (xchg(&root->fs_info->enospc_unlink, 1))
2928  return ERR_PTR(-ENOSPC);
2929 
2930  path = btrfs_alloc_path();
2931  if (!path) {
2932  root->fs_info->enospc_unlink = 0;
2933  return ERR_PTR(-ENOMEM);
2934  }
2935 
2936  /* 1 for the orphan item */
2937  trans = btrfs_start_transaction(root, 1);
2938  if (IS_ERR(trans)) {
2939  btrfs_free_path(path);
2940  root->fs_info->enospc_unlink = 0;
2941  return trans;
2942  }
2943 
2944  path->skip_locking = 1;
2945  path->search_commit_root = 1;
2946 
2947  ret = btrfs_lookup_inode(trans, root, path,
2948  &BTRFS_I(dir)->location, 0);
2949  if (ret < 0) {
2950  err = ret;
2951  goto out;
2952  }
2953  if (ret == 0) {
2954  if (check_path_shared(root, path))
2955  goto out;
2956  } else {
2957  check_link = 0;
2958  }
2959  btrfs_release_path(path);
2960 
2961  ret = btrfs_lookup_inode(trans, root, path,
2962  &BTRFS_I(inode)->location, 0);
2963  if (ret < 0) {
2964  err = ret;
2965  goto out;
2966  }
2967  if (ret == 0) {
2968  if (check_path_shared(root, path))
2969  goto out;
2970  } else {
2971  check_link = 0;
2972  }
2973  btrfs_release_path(path);
2974 
2975  if (ret == 0 && S_ISREG(inode->i_mode)) {
2976  ret = btrfs_lookup_file_extent(trans, root, path,
2977  ino, (u64)-1, 0);
2978  if (ret < 0) {
2979  err = ret;
2980  goto out;
2981  }
2982  BUG_ON(ret == 0); /* Corruption */
2983  if (check_path_shared(root, path))
2984  goto out;
2985  btrfs_release_path(path);
2986  }
2987 
2988  if (!check_link) {
2989  err = 0;
2990  goto out;
2991  }
2992 
2993  di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
2994  dentry->d_name.name, dentry->d_name.len, 0);
2995  if (IS_ERR(di)) {
2996  err = PTR_ERR(di);
2997  goto out;
2998  }
2999  if (di) {
3000  if (check_path_shared(root, path))
3001  goto out;
3002  } else {
3003  err = 0;
3004  goto out;
3005  }
3006  btrfs_release_path(path);
3007 
3008  ret = btrfs_get_inode_ref_index(trans, root, path, dentry->d_name.name,
3009  dentry->d_name.len, ino, dir_ino, 0,
3010  &index);
3011  if (ret) {
3012  err = ret;
3013  goto out;
3014  }
3015 
3016  if (check_path_shared(root, path))
3017  goto out;
3018 
3019  btrfs_release_path(path);
3020 
3021  /*
3022  * This is a commit root search, if we can lookup inode item and other
3023  * relative items in the commit root, it means the transaction of
3024  * dir/file creation has been committed, and the dir index item that we
3025  * delay to insert has also been inserted into the commit root. So
3026  * we needn't worry about the delayed insertion of the dir index item
3027  * here.
3028  */
3029  di = btrfs_lookup_dir_index_item(trans, root, path, dir_ino, index,
3030  dentry->d_name.name, dentry->d_name.len, 0);
3031  if (IS_ERR(di)) {
3032  err = PTR_ERR(di);
3033  goto out;
3034  }
3035  BUG_ON(ret == -ENOENT);
3036  if (check_path_shared(root, path))
3037  goto out;
3038 
3039  err = 0;
3040 out:
3041  btrfs_free_path(path);
3042  /* Migrate the orphan reservation over */
3043  if (!err)
3044  err = btrfs_block_rsv_migrate(trans->block_rsv,
3045  &root->fs_info->global_block_rsv,
3046  trans->bytes_reserved);
3047 
3048  if (err) {
3049  btrfs_end_transaction(trans, root);
3050  root->fs_info->enospc_unlink = 0;
3051  return ERR_PTR(err);
3052  }
3053 
3054  trans->block_rsv = &root->fs_info->global_block_rsv;
3055  return trans;
3056 }
3057 
3058 static void __unlink_end_trans(struct btrfs_trans_handle *trans,
3059  struct btrfs_root *root)
3060 {
3061  if (trans->block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL) {
3062  btrfs_block_rsv_release(root, trans->block_rsv,
3063  trans->bytes_reserved);
3064  trans->block_rsv = &root->fs_info->trans_block_rsv;
3065  BUG_ON(!root->fs_info->enospc_unlink);
3066  root->fs_info->enospc_unlink = 0;
3067  }
3068  btrfs_end_transaction(trans, root);
3069 }
3070 
3071 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
3072 {
3073  struct btrfs_root *root = BTRFS_I(dir)->root;
3074  struct btrfs_trans_handle *trans;
3075  struct inode *inode = dentry->d_inode;
3076  int ret;
3077  unsigned long nr = 0;
3078 
3079  trans = __unlink_start_trans(dir, dentry);
3080  if (IS_ERR(trans))
3081  return PTR_ERR(trans);
3082 
3083  btrfs_record_unlink_dir(trans, dir, dentry->d_inode, 0);
3084 
3085  ret = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3086  dentry->d_name.name, dentry->d_name.len);
3087  if (ret)
3088  goto out;
3089 
3090  if (inode->i_nlink == 0) {
3091  ret = btrfs_orphan_add(trans, inode);
3092  if (ret)
3093  goto out;
3094  }
3095 
3096 out:
3097  nr = trans->blocks_used;
3098  __unlink_end_trans(trans, root);
3099  btrfs_btree_balance_dirty(root, nr);
3100  return ret;
3101 }
3102 
3104  struct btrfs_root *root,
3105  struct inode *dir, u64 objectid,
3106  const char *name, int name_len)
3107 {
3108  struct btrfs_path *path;
3109  struct extent_buffer *leaf;
3110  struct btrfs_dir_item *di;
3111  struct btrfs_key key;
3112  u64 index;
3113  int ret;
3114  u64 dir_ino = btrfs_ino(dir);
3115 
3116  path = btrfs_alloc_path();
3117  if (!path)
3118  return -ENOMEM;
3119 
3120  di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3121  name, name_len, -1);
3122  if (IS_ERR_OR_NULL(di)) {
3123  if (!di)
3124  ret = -ENOENT;
3125  else
3126  ret = PTR_ERR(di);
3127  goto out;
3128  }
3129 
3130  leaf = path->nodes[0];
3131  btrfs_dir_item_key_to_cpu(leaf, di, &key);
3132  WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
3133  ret = btrfs_delete_one_dir_name(trans, root, path, di);
3134  if (ret) {
3135  btrfs_abort_transaction(trans, root, ret);
3136  goto out;
3137  }
3138  btrfs_release_path(path);
3139 
3140  ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
3141  objectid, root->root_key.objectid,
3142  dir_ino, &index, name, name_len);
3143  if (ret < 0) {
3144  if (ret != -ENOENT) {
3145  btrfs_abort_transaction(trans, root, ret);
3146  goto out;
3147  }
3148  di = btrfs_search_dir_index_item(root, path, dir_ino,
3149  name, name_len);
3150  if (IS_ERR_OR_NULL(di)) {
3151  if (!di)
3152  ret = -ENOENT;
3153  else
3154  ret = PTR_ERR(di);
3155  btrfs_abort_transaction(trans, root, ret);
3156  goto out;
3157  }
3158 
3159  leaf = path->nodes[0];
3160  btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3161  btrfs_release_path(path);
3162  index = key.offset;
3163  }
3164  btrfs_release_path(path);
3165 
3166  ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
3167  if (ret) {
3168  btrfs_abort_transaction(trans, root, ret);
3169  goto out;
3170  }
3171 
3172  btrfs_i_size_write(dir, dir->i_size - name_len * 2);
3173  inode_inc_iversion(dir);
3174  dir->i_mtime = dir->i_ctime = CURRENT_TIME;
3175  ret = btrfs_update_inode_fallback(trans, root, dir);
3176  if (ret)
3177  btrfs_abort_transaction(trans, root, ret);
3178 out:
3179  btrfs_free_path(path);
3180  return ret;
3181 }
3182 
3183 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
3184 {
3185  struct inode *inode = dentry->d_inode;
3186  int err = 0;
3187  struct btrfs_root *root = BTRFS_I(dir)->root;
3188  struct btrfs_trans_handle *trans;
3189  unsigned long nr = 0;
3190 
3191  if (inode->i_size > BTRFS_EMPTY_DIR_SIZE)
3192  return -ENOTEMPTY;
3193  if (btrfs_ino(inode) == BTRFS_FIRST_FREE_OBJECTID)
3194  return -EPERM;
3195 
3196  trans = __unlink_start_trans(dir, dentry);
3197  if (IS_ERR(trans))
3198  return PTR_ERR(trans);
3199 
3200  if (unlikely(btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
3201  err = btrfs_unlink_subvol(trans, root, dir,
3202  BTRFS_I(inode)->location.objectid,
3203  dentry->d_name.name,
3204  dentry->d_name.len);
3205  goto out;
3206  }
3207 
3208  err = btrfs_orphan_add(trans, inode);
3209  if (err)
3210  goto out;
3211 
3212  /* now the directory is empty */
3213  err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3214  dentry->d_name.name, dentry->d_name.len);
3215  if (!err)
3216  btrfs_i_size_write(inode, 0);
3217 out:
3218  nr = trans->blocks_used;
3219  __unlink_end_trans(trans, root);
3220  btrfs_btree_balance_dirty(root, nr);
3221 
3222  return err;
3223 }
3224 
3225 /*
3226  * this can truncate away extent items, csum items and directory items.
3227  * It starts at a high offset and removes keys until it can't find
3228  * any higher than new_size
3229  *
3230  * csum items that cross the new i_size are truncated to the new size
3231  * as well.
3232  *
3233  * min_type is the minimum key type to truncate down to. If set to 0, this
3234  * will kill all the items on this inode, including the INODE_ITEM_KEY.
3235  */
3237  struct btrfs_root *root,
3238  struct inode *inode,
3239  u64 new_size, u32 min_type)
3240 {
3241  struct btrfs_path *path;
3242  struct extent_buffer *leaf;
3243  struct btrfs_file_extent_item *fi;
3244  struct btrfs_key key;
3245  struct btrfs_key found_key;
3246  u64 extent_start = 0;
3247  u64 extent_num_bytes = 0;
3248  u64 extent_offset = 0;
3249  u64 item_end = 0;
3250  u64 mask = root->sectorsize - 1;
3251  u32 found_type = (u8)-1;
3252  int found_extent;
3253  int del_item;
3254  int pending_del_nr = 0;
3255  int pending_del_slot = 0;
3256  int extent_type = -1;
3257  int ret;
3258  int err = 0;
3259  u64 ino = btrfs_ino(inode);
3260 
3261  BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
3262 
3263  path = btrfs_alloc_path();
3264  if (!path)
3265  return -ENOMEM;
3266  path->reada = -1;
3267 
3268  /*
3269  * We want to drop from the next block forward in case this new size is
3270  * not block aligned since we will be keeping the last block of the
3271  * extent just the way it is.
3272  */
3273  if (root->ref_cows || root == root->fs_info->tree_root)
3274  btrfs_drop_extent_cache(inode, (new_size + mask) & (~mask), (u64)-1, 0);
3275 
3276  /*
3277  * This function is also used to drop the items in the log tree before
3278  * we relog the inode, so if root != BTRFS_I(inode)->root, it means
3279  * it is used to drop the loged items. So we shouldn't kill the delayed
3280  * items.
3281  */
3282  if (min_type == 0 && root == BTRFS_I(inode)->root)
3284 
3285  key.objectid = ino;
3286  key.offset = (u64)-1;
3287  key.type = (u8)-1;
3288 
3289 search_again:
3290  path->leave_spinning = 1;
3291  ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3292  if (ret < 0) {
3293  err = ret;
3294  goto out;
3295  }
3296 
3297  if (ret > 0) {
3298  /* there are no items in the tree for us to truncate, we're
3299  * done
3300  */
3301  if (path->slots[0] == 0)
3302  goto out;
3303  path->slots[0]--;
3304  }
3305 
3306  while (1) {
3307  fi = NULL;
3308  leaf = path->nodes[0];
3309  btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3310  found_type = btrfs_key_type(&found_key);
3311 
3312  if (found_key.objectid != ino)
3313  break;
3314 
3315  if (found_type < min_type)
3316  break;
3317 
3318  item_end = found_key.offset;
3319  if (found_type == BTRFS_EXTENT_DATA_KEY) {
3320  fi = btrfs_item_ptr(leaf, path->slots[0],
3321  struct btrfs_file_extent_item);
3322  extent_type = btrfs_file_extent_type(leaf, fi);
3323  if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
3324  item_end +=
3325  btrfs_file_extent_num_bytes(leaf, fi);
3326  } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
3327  item_end += btrfs_file_extent_inline_len(leaf,
3328  fi);
3329  }
3330  item_end--;
3331  }
3332  if (found_type > min_type) {
3333  del_item = 1;
3334  } else {
3335  if (item_end < new_size)
3336  break;
3337  if (found_key.offset >= new_size)
3338  del_item = 1;
3339  else
3340  del_item = 0;
3341  }
3342  found_extent = 0;
3343  /* FIXME, shrink the extent if the ref count is only 1 */
3344  if (found_type != BTRFS_EXTENT_DATA_KEY)
3345  goto delete;
3346 
3347  if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
3348  u64 num_dec;
3349  extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
3350  if (!del_item) {
3351  u64 orig_num_bytes =
3352  btrfs_file_extent_num_bytes(leaf, fi);
3353  extent_num_bytes = new_size -
3354  found_key.offset + root->sectorsize - 1;
3355  extent_num_bytes = extent_num_bytes &
3356  ~((u64)root->sectorsize - 1);
3357  btrfs_set_file_extent_num_bytes(leaf, fi,
3358  extent_num_bytes);
3359  num_dec = (orig_num_bytes -
3360  extent_num_bytes);
3361  if (root->ref_cows && extent_start != 0)
3362  inode_sub_bytes(inode, num_dec);
3364  } else {
3365  extent_num_bytes =
3366  btrfs_file_extent_disk_num_bytes(leaf,
3367  fi);
3368  extent_offset = found_key.offset -
3369  btrfs_file_extent_offset(leaf, fi);
3370 
3371  /* FIXME blocksize != 4096 */
3372  num_dec = btrfs_file_extent_num_bytes(leaf, fi);
3373  if (extent_start != 0) {
3374  found_extent = 1;
3375  if (root->ref_cows)
3376  inode_sub_bytes(inode, num_dec);
3377  }
3378  }
3379  } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
3380  /*
3381  * we can't truncate inline items that have had
3382  * special encodings
3383  */
3384  if (!del_item &&
3385  btrfs_file_extent_compression(leaf, fi) == 0 &&
3386  btrfs_file_extent_encryption(leaf, fi) == 0 &&
3387  btrfs_file_extent_other_encoding(leaf, fi) == 0) {
3388  u32 size = new_size - found_key.offset;
3389 
3390  if (root->ref_cows) {
3391  inode_sub_bytes(inode, item_end + 1 -
3392  new_size);
3393  }
3394  size =
3395  btrfs_file_extent_calc_inline_size(size);
3396  btrfs_truncate_item(trans, root, path,
3397  size, 1);
3398  } else if (root->ref_cows) {
3399  inode_sub_bytes(inode, item_end + 1 -
3400  found_key.offset);
3401  }
3402  }
3403 delete:
3404  if (del_item) {
3405  if (!pending_del_nr) {
3406  /* no pending yet, add ourselves */
3407  pending_del_slot = path->slots[0];
3408  pending_del_nr = 1;
3409  } else if (pending_del_nr &&
3410  path->slots[0] + 1 == pending_del_slot) {
3411  /* hop on the pending chunk */
3412  pending_del_nr++;
3413  pending_del_slot = path->slots[0];
3414  } else {
3415  BUG();
3416  }
3417  } else {
3418  break;
3419  }
3420  if (found_extent && (root->ref_cows ||
3421  root == root->fs_info->tree_root)) {
3423  ret = btrfs_free_extent(trans, root, extent_start,
3424  extent_num_bytes, 0,
3425  btrfs_header_owner(leaf),
3426  ino, extent_offset, 0);
3427  BUG_ON(ret);
3428  }
3429 
3430  if (found_type == BTRFS_INODE_ITEM_KEY)
3431  break;
3432 
3433  if (path->slots[0] == 0 ||
3434  path->slots[0] != pending_del_slot) {
3435  if (pending_del_nr) {
3436  ret = btrfs_del_items(trans, root, path,
3437  pending_del_slot,
3438  pending_del_nr);
3439  if (ret) {
3441  root, ret);
3442  goto error;
3443  }
3444  pending_del_nr = 0;
3445  }
3446  btrfs_release_path(path);
3447  goto search_again;
3448  } else {
3449  path->slots[0]--;
3450  }
3451  }
3452 out:
3453  if (pending_del_nr) {
3454  ret = btrfs_del_items(trans, root, path, pending_del_slot,
3455  pending_del_nr);
3456  if (ret)
3457  btrfs_abort_transaction(trans, root, ret);
3458  }
3459 error:
3460  btrfs_free_path(path);
3461  return err;
3462 }
3463 
3464 /*
3465  * btrfs_truncate_page - read, zero a chunk and write a page
3466  * @inode - inode that we're zeroing
3467  * @from - the offset to start zeroing
3468  * @len - the length to zero, 0 to zero the entire range respective to the
3469  * offset
3470  * @front - zero up to the offset instead of from the offset on
3471  *
3472  * This will find the page for the "from" offset and cow the page and zero the
3473  * part we want to zero. This is used with truncate and hole punching.
3474  */
3475 int btrfs_truncate_page(struct inode *inode, loff_t from, loff_t len,
3476  int front)
3477 {
3478  struct address_space *mapping = inode->i_mapping;
3479  struct btrfs_root *root = BTRFS_I(inode)->root;
3480  struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3481  struct btrfs_ordered_extent *ordered;
3482  struct extent_state *cached_state = NULL;
3483  char *kaddr;
3484  u32 blocksize = root->sectorsize;
3485  pgoff_t index = from >> PAGE_CACHE_SHIFT;
3486  unsigned offset = from & (PAGE_CACHE_SIZE-1);
3487  struct page *page;
3488  gfp_t mask = btrfs_alloc_write_mask(mapping);
3489  int ret = 0;
3490  u64 page_start;
3491  u64 page_end;
3492 
3493  if ((offset & (blocksize - 1)) == 0 &&
3494  (!len || ((len & (blocksize - 1)) == 0)))
3495  goto out;
3497  if (ret)
3498  goto out;
3499 
3500  ret = -ENOMEM;
3501 again:
3502  page = find_or_create_page(mapping, index, mask);
3503  if (!page) {
3505  goto out;
3506  }
3507 
3508  page_start = page_offset(page);
3509  page_end = page_start + PAGE_CACHE_SIZE - 1;
3510 
3511  if (!PageUptodate(page)) {
3512  ret = btrfs_readpage(NULL, page);
3513  lock_page(page);
3514  if (page->mapping != mapping) {
3515  unlock_page(page);
3516  page_cache_release(page);
3517  goto again;
3518  }
3519  if (!PageUptodate(page)) {
3520  ret = -EIO;
3521  goto out_unlock;
3522  }
3523  }
3524  wait_on_page_writeback(page);
3525 
3526  lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state);
3527  set_page_extent_mapped(page);
3528 
3529  ordered = btrfs_lookup_ordered_extent(inode, page_start);
3530  if (ordered) {
3531  unlock_extent_cached(io_tree, page_start, page_end,
3532  &cached_state, GFP_NOFS);
3533  unlock_page(page);
3534  page_cache_release(page);
3535  btrfs_start_ordered_extent(inode, ordered, 1);
3536  btrfs_put_ordered_extent(ordered);
3537  goto again;
3538  }
3539 
3540  clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
3541  EXTENT_DIRTY | EXTENT_DELALLOC |
3542  EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
3543  0, 0, &cached_state, GFP_NOFS);
3544 
3545  ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
3546  &cached_state);
3547  if (ret) {
3548  unlock_extent_cached(io_tree, page_start, page_end,
3549  &cached_state, GFP_NOFS);
3550  goto out_unlock;
3551  }
3552 
3553  ret = 0;
3554  if (offset != PAGE_CACHE_SIZE) {
3555  if (!len)
3556  len = PAGE_CACHE_SIZE - offset;
3557  kaddr = kmap(page);
3558  if (front)
3559  memset(kaddr, 0, offset);
3560  else
3561  memset(kaddr + offset, 0, len);
3562  flush_dcache_page(page);
3563  kunmap(page);
3564  }
3565  ClearPageChecked(page);
3566  set_page_dirty(page);
3567  unlock_extent_cached(io_tree, page_start, page_end, &cached_state,
3568  GFP_NOFS);
3569 
3570 out_unlock:
3571  if (ret)
3572  btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
3573  unlock_page(page);
3574  page_cache_release(page);
3575 out:
3576  return ret;
3577 }
3578 
3579 /*
3580  * This function puts in dummy file extents for the area we're creating a hole
3581  * for. So if we are truncating this file to a larger size we need to insert
3582  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
3583  * the range between oldsize and size
3584  */
3585 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
3586 {
3587  struct btrfs_trans_handle *trans;
3588  struct btrfs_root *root = BTRFS_I(inode)->root;
3589  struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3590  struct extent_map *em = NULL;
3591  struct extent_state *cached_state = NULL;
3592  struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3593  u64 mask = root->sectorsize - 1;
3594  u64 hole_start = (oldsize + mask) & ~mask;
3595  u64 block_end = (size + mask) & ~mask;
3596  u64 last_byte;
3597  u64 cur_offset;
3598  u64 hole_size;
3599  int err = 0;
3600 
3601  if (size <= hole_start)
3602  return 0;
3603 
3604  while (1) {
3605  struct btrfs_ordered_extent *ordered;
3606  btrfs_wait_ordered_range(inode, hole_start,
3607  block_end - hole_start);
3608  lock_extent_bits(io_tree, hole_start, block_end - 1, 0,
3609  &cached_state);
3610  ordered = btrfs_lookup_ordered_extent(inode, hole_start);
3611  if (!ordered)
3612  break;
3613  unlock_extent_cached(io_tree, hole_start, block_end - 1,
3614  &cached_state, GFP_NOFS);
3615  btrfs_put_ordered_extent(ordered);
3616  }
3617 
3618  cur_offset = hole_start;
3619  while (1) {
3620  em = btrfs_get_extent(inode, NULL, 0, cur_offset,
3621  block_end - cur_offset, 0);
3622  if (IS_ERR(em)) {
3623  err = PTR_ERR(em);
3624  break;
3625  }
3626  last_byte = min(extent_map_end(em), block_end);
3627  last_byte = (last_byte + mask) & ~mask;
3628  if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
3629  struct extent_map *hole_em;
3630  hole_size = last_byte - cur_offset;
3631 
3632  trans = btrfs_start_transaction(root, 3);
3633  if (IS_ERR(trans)) {
3634  err = PTR_ERR(trans);
3635  break;
3636  }
3637 
3638  err = btrfs_drop_extents(trans, root, inode,
3639  cur_offset,
3640  cur_offset + hole_size, 1);
3641  if (err) {
3642  btrfs_abort_transaction(trans, root, err);
3643  btrfs_end_transaction(trans, root);
3644  break;
3645  }
3646 
3647  err = btrfs_insert_file_extent(trans, root,
3648  btrfs_ino(inode), cur_offset, 0,
3649  0, hole_size, 0, hole_size,
3650  0, 0, 0);
3651  if (err) {
3652  btrfs_abort_transaction(trans, root, err);
3653  btrfs_end_transaction(trans, root);
3654  break;
3655  }
3656 
3657  btrfs_drop_extent_cache(inode, cur_offset,
3658  cur_offset + hole_size - 1, 0);
3659  hole_em = alloc_extent_map();
3660  if (!hole_em) {
3662  &BTRFS_I(inode)->runtime_flags);
3663  goto next;
3664  }
3665  hole_em->start = cur_offset;
3666  hole_em->len = hole_size;
3667  hole_em->orig_start = cur_offset;
3668 
3669  hole_em->block_start = EXTENT_MAP_HOLE;
3670  hole_em->block_len = 0;
3671  hole_em->bdev = root->fs_info->fs_devices->latest_bdev;
3673  hole_em->generation = trans->transid;
3674 
3675  while (1) {
3676  write_lock(&em_tree->lock);
3677  err = add_extent_mapping(em_tree, hole_em);
3678  if (!err)
3679  list_move(&hole_em->list,
3680  &em_tree->modified_extents);
3681  write_unlock(&em_tree->lock);
3682  if (err != -EEXIST)
3683  break;
3684  btrfs_drop_extent_cache(inode, cur_offset,
3685  cur_offset +
3686  hole_size - 1, 0);
3687  }
3688  free_extent_map(hole_em);
3689 next:
3690  btrfs_update_inode(trans, root, inode);
3691  btrfs_end_transaction(trans, root);
3692  }
3693  free_extent_map(em);
3694  em = NULL;
3695  cur_offset = last_byte;
3696  if (cur_offset >= block_end)
3697  break;
3698  }
3699 
3700  free_extent_map(em);
3701  unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state,
3702  GFP_NOFS);
3703  return err;
3704 }
3705 
3706 static int btrfs_setsize(struct inode *inode, loff_t newsize)
3707 {
3708  struct btrfs_root *root = BTRFS_I(inode)->root;
3709  struct btrfs_trans_handle *trans;
3710  loff_t oldsize = i_size_read(inode);
3711  int ret;
3712 
3713  if (newsize == oldsize)
3714  return 0;
3715 
3716  if (newsize > oldsize) {
3717  truncate_pagecache(inode, oldsize, newsize);
3718  ret = btrfs_cont_expand(inode, oldsize, newsize);
3719  if (ret)
3720  return ret;
3721 
3722  trans = btrfs_start_transaction(root, 1);
3723  if (IS_ERR(trans))
3724  return PTR_ERR(trans);
3725 
3726  i_size_write(inode, newsize);
3727  btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
3728  ret = btrfs_update_inode(trans, root, inode);
3729  btrfs_end_transaction(trans, root);
3730  } else {
3731 
3732  /*
3733  * We're truncating a file that used to have good data down to
3734  * zero. Make sure it gets into the ordered flush list so that
3735  * any new writes get down to disk quickly.
3736  */
3737  if (newsize == 0)
3739  &BTRFS_I(inode)->runtime_flags);
3740 
3741  /* we don't support swapfiles, so vmtruncate shouldn't fail */
3742  truncate_setsize(inode, newsize);
3743  ret = btrfs_truncate(inode);
3744  }
3745 
3746  return ret;
3747 }
3748 
3749 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
3750 {
3751  struct inode *inode = dentry->d_inode;
3752  struct btrfs_root *root = BTRFS_I(inode)->root;
3753  int err;
3754 
3755  if (btrfs_root_readonly(root))
3756  return -EROFS;
3757 
3758  err = inode_change_ok(inode, attr);
3759  if (err)
3760  return err;
3761 
3762  if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
3763  err = btrfs_setsize(inode, attr->ia_size);
3764  if (err)
3765  return err;
3766  }
3767 
3768  if (attr->ia_valid) {
3769  setattr_copy(inode, attr);
3770  inode_inc_iversion(inode);
3771  err = btrfs_dirty_inode(inode);
3772 
3773  if (!err && attr->ia_valid & ATTR_MODE)
3774  err = btrfs_acl_chmod(inode);
3775  }
3776 
3777  return err;
3778 }
3779 
3780 void btrfs_evict_inode(struct inode *inode)
3781 {
3782  struct btrfs_trans_handle *trans;
3783  struct btrfs_root *root = BTRFS_I(inode)->root;
3784  struct btrfs_block_rsv *rsv, *global_rsv;
3785  u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
3786  unsigned long nr;
3787  int ret;
3788 
3789  trace_btrfs_inode_evict(inode);
3790 
3791  truncate_inode_pages(&inode->i_data, 0);
3792  if (inode->i_nlink && (btrfs_root_refs(&root->root_item) != 0 ||
3793  btrfs_is_free_space_inode(inode)))
3794  goto no_delete;
3795 
3796  if (is_bad_inode(inode)) {
3797  btrfs_orphan_del(NULL, inode);
3798  goto no_delete;
3799  }
3800  /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
3801  btrfs_wait_ordered_range(inode, 0, (u64)-1);
3802 
3803  if (root->fs_info->log_root_recovering) {
3805  &BTRFS_I(inode)->runtime_flags));
3806  goto no_delete;
3807  }
3808 
3809  if (inode->i_nlink > 0) {
3810  BUG_ON(btrfs_root_refs(&root->root_item) != 0);
3811  goto no_delete;
3812  }
3813 
3815  if (!rsv) {
3816  btrfs_orphan_del(NULL, inode);
3817  goto no_delete;
3818  }
3819  rsv->size = min_size;
3820  rsv->failfast = 1;
3821  global_rsv = &root->fs_info->global_block_rsv;
3822 
3823  btrfs_i_size_write(inode, 0);
3824 
3825  /*
3826  * This is a bit simpler than btrfs_truncate since we've already
3827  * reserved our space for our orphan item in the unlink, so we just
3828  * need to reserve some slack space in case we add bytes and update
3829  * inode item when doing the truncate.
3830  */
3831  while (1) {
3832  ret = btrfs_block_rsv_refill_noflush(root, rsv, min_size);
3833 
3834  /*
3835  * Try and steal from the global reserve since we will
3836  * likely not use this space anyway, we want to try as
3837  * hard as possible to get this to work.
3838  */
3839  if (ret)
3840  ret = btrfs_block_rsv_migrate(global_rsv, rsv, min_size);
3841 
3842  if (ret) {
3843  printk(KERN_WARNING "Could not get space for a "
3844  "delete, will truncate on mount %d\n", ret);
3845  btrfs_orphan_del(NULL, inode);
3846  btrfs_free_block_rsv(root, rsv);
3847  goto no_delete;
3848  }
3849 
3850  trans = btrfs_start_transaction_noflush(root, 1);
3851  if (IS_ERR(trans)) {
3852  btrfs_orphan_del(NULL, inode);
3853  btrfs_free_block_rsv(root, rsv);
3854  goto no_delete;
3855  }
3856 
3857  trans->block_rsv = rsv;
3858 
3859  ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
3860  if (ret != -ENOSPC)
3861  break;
3862 
3863  trans->block_rsv = &root->fs_info->trans_block_rsv;
3864  ret = btrfs_update_inode(trans, root, inode);
3865  BUG_ON(ret);
3866 
3867  nr = trans->blocks_used;
3868  btrfs_end_transaction(trans, root);
3869  trans = NULL;
3870  btrfs_btree_balance_dirty(root, nr);
3871  }
3872 
3873  btrfs_free_block_rsv(root, rsv);
3874 
3875  if (ret == 0) {
3876  trans->block_rsv = root->orphan_block_rsv;
3877  ret = btrfs_orphan_del(trans, inode);
3878  BUG_ON(ret);
3879  }
3880 
3881  trans->block_rsv = &root->fs_info->trans_block_rsv;
3882  if (!(root == root->fs_info->tree_root ||
3883  root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
3884  btrfs_return_ino(root, btrfs_ino(inode));
3885 
3886  nr = trans->blocks_used;
3887  btrfs_end_transaction(trans, root);
3888  btrfs_btree_balance_dirty(root, nr);
3889 no_delete:
3890  clear_inode(inode);
3891  return;
3892 }
3893 
3894 /*
3895  * this returns the key found in the dir entry in the location pointer.
3896  * If no dir entries were found, location->objectid is 0.
3897  */
3898 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
3899  struct btrfs_key *location)
3900 {
3901  const char *name = dentry->d_name.name;
3902  int namelen = dentry->d_name.len;
3903  struct btrfs_dir_item *di;
3904  struct btrfs_path *path;
3905  struct btrfs_root *root = BTRFS_I(dir)->root;
3906  int ret = 0;
3907 
3908  path = btrfs_alloc_path();
3909  if (!path)
3910  return -ENOMEM;
3911 
3912  di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(dir), name,
3913  namelen, 0);
3914  if (IS_ERR(di))
3915  ret = PTR_ERR(di);
3916 
3917  if (IS_ERR_OR_NULL(di))
3918  goto out_err;
3919 
3920  btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
3921 out:
3922  btrfs_free_path(path);
3923  return ret;
3924 out_err:
3925  location->objectid = 0;
3926  goto out;
3927 }
3928 
3929 /*
3930  * when we hit a tree root in a directory, the btrfs part of the inode
3931  * needs to be changed to reflect the root directory of the tree root. This
3932  * is kind of like crossing a mount point.
3933  */
3934 static int fixup_tree_root_location(struct btrfs_root *root,
3935  struct inode *dir,
3936  struct dentry *dentry,
3937  struct btrfs_key *location,
3938  struct btrfs_root **sub_root)
3939 {
3940  struct btrfs_path *path;
3941  struct btrfs_root *new_root;
3942  struct btrfs_root_ref *ref;
3943  struct extent_buffer *leaf;
3944  int ret;
3945  int err = 0;
3946 
3947  path = btrfs_alloc_path();
3948  if (!path) {
3949  err = -ENOMEM;
3950  goto out;
3951  }
3952 
3953  err = -ENOENT;
3954  ret = btrfs_find_root_ref(root->fs_info->tree_root, path,
3955  BTRFS_I(dir)->root->root_key.objectid,
3956  location->objectid);
3957  if (ret) {
3958  if (ret < 0)
3959  err = ret;
3960  goto out;
3961  }
3962 
3963  leaf = path->nodes[0];
3964  ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
3965  if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(dir) ||
3966  btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
3967  goto out;
3968 
3969  ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
3970  (unsigned long)(ref + 1),
3971  dentry->d_name.len);
3972  if (ret)
3973  goto out;
3974 
3975  btrfs_release_path(path);
3976 
3977  new_root = btrfs_read_fs_root_no_name(root->fs_info, location);
3978  if (IS_ERR(new_root)) {
3979  err = PTR_ERR(new_root);
3980  goto out;
3981  }
3982 
3983  if (btrfs_root_refs(&new_root->root_item) == 0) {
3984  err = -ENOENT;
3985  goto out;
3986  }
3987 
3988  *sub_root = new_root;
3989  location->objectid = btrfs_root_dirid(&new_root->root_item);
3990  location->type = BTRFS_INODE_ITEM_KEY;
3991  location->offset = 0;
3992  err = 0;
3993 out:
3994  btrfs_free_path(path);
3995  return err;
3996 }
3997 
3998 static void inode_tree_add(struct inode *inode)
3999 {
4000  struct btrfs_root *root = BTRFS_I(inode)->root;
4001  struct btrfs_inode *entry;
4002  struct rb_node **p;
4003  struct rb_node *parent;
4004  u64 ino = btrfs_ino(inode);
4005 again:
4006  p = &root->inode_tree.rb_node;
4007  parent = NULL;
4008 
4009  if (inode_unhashed(inode))
4010  return;
4011 
4012  spin_lock(&root->inode_lock);
4013  while (*p) {
4014  parent = *p;
4015  entry = rb_entry(parent, struct btrfs_inode, rb_node);
4016 
4017  if (ino < btrfs_ino(&entry->vfs_inode))
4018  p = &parent->rb_left;
4019  else if (ino > btrfs_ino(&entry->vfs_inode))
4020  p = &parent->rb_right;
4021  else {
4022  WARN_ON(!(entry->vfs_inode.i_state &
4023  (I_WILL_FREE | I_FREEING)));
4024  rb_erase(parent, &root->inode_tree);
4025  RB_CLEAR_NODE(parent);
4026  spin_unlock(&root->inode_lock);
4027  goto again;
4028  }
4029  }
4030  rb_link_node(&BTRFS_I(inode)->rb_node, parent, p);
4031  rb_insert_color(&BTRFS_I(inode)->rb_node, &root->inode_tree);
4032  spin_unlock(&root->inode_lock);
4033 }
4034 
4035 static void inode_tree_del(struct inode *inode)
4036 {
4037  struct btrfs_root *root = BTRFS_I(inode)->root;
4038  int empty = 0;
4039 
4040  spin_lock(&root->inode_lock);
4041  if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
4042  rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
4043  RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
4044  empty = RB_EMPTY_ROOT(&root->inode_tree);
4045  }
4046  spin_unlock(&root->inode_lock);
4047 
4048  /*
4049  * Free space cache has inodes in the tree root, but the tree root has a
4050  * root_refs of 0, so this could end up dropping the tree root as a
4051  * snapshot, so we need the extra !root->fs_info->tree_root check to
4052  * make sure we don't drop it.
4053  */
4054  if (empty && btrfs_root_refs(&root->root_item) == 0 &&
4055  root != root->fs_info->tree_root) {
4056  synchronize_srcu(&root->fs_info->subvol_srcu);
4057  spin_lock(&root->inode_lock);
4058  empty = RB_EMPTY_ROOT(&root->inode_tree);
4059  spin_unlock(&root->inode_lock);
4060  if (empty)
4061  btrfs_add_dead_root(root);
4062  }
4063 }
4064 
4066 {
4067  struct rb_node *node;
4068  struct rb_node *prev;
4069  struct btrfs_inode *entry;
4070  struct inode *inode;
4071  u64 objectid = 0;
4072 
4073  WARN_ON(btrfs_root_refs(&root->root_item) != 0);
4074 
4075  spin_lock(&root->inode_lock);
4076 again:
4077  node = root->inode_tree.rb_node;
4078  prev = NULL;
4079  while (node) {
4080  prev = node;
4081  entry = rb_entry(node, struct btrfs_inode, rb_node);
4082 
4083  if (objectid < btrfs_ino(&entry->vfs_inode))
4084  node = node->rb_left;
4085  else if (objectid > btrfs_ino(&entry->vfs_inode))
4086  node = node->rb_right;
4087  else
4088  break;
4089  }
4090  if (!node) {
4091  while (prev) {
4092  entry = rb_entry(prev, struct btrfs_inode, rb_node);
4093  if (objectid <= btrfs_ino(&entry->vfs_inode)) {
4094  node = prev;
4095  break;
4096  }
4097  prev = rb_next(prev);
4098  }
4099  }
4100  while (node) {
4101  entry = rb_entry(node, struct btrfs_inode, rb_node);
4102  objectid = btrfs_ino(&entry->vfs_inode) + 1;
4103  inode = igrab(&entry->vfs_inode);
4104  if (inode) {
4105  spin_unlock(&root->inode_lock);
4106  if (atomic_read(&inode->i_count) > 1)
4107  d_prune_aliases(inode);
4108  /*
4109  * btrfs_drop_inode will have it removed from
4110  * the inode cache when its usage count
4111  * hits zero.
4112  */
4113  iput(inode);
4114  cond_resched();
4115  spin_lock(&root->inode_lock);
4116  goto again;
4117  }
4118 
4119  if (cond_resched_lock(&root->inode_lock))
4120  goto again;
4121 
4122  node = rb_next(node);
4123  }
4124  spin_unlock(&root->inode_lock);
4125 }
4126 
4127 static int btrfs_init_locked_inode(struct inode *inode, void *p)
4128 {
4129  struct btrfs_iget_args *args = p;
4130  inode->i_ino = args->ino;
4131  BTRFS_I(inode)->root = args->root;
4132  return 0;
4133 }
4134 
4135 static int btrfs_find_actor(struct inode *inode, void *opaque)
4136 {
4137  struct btrfs_iget_args *args = opaque;
4138  return args->ino == btrfs_ino(inode) &&
4139  args->root == BTRFS_I(inode)->root;
4140 }
4141 
4142 static struct inode *btrfs_iget_locked(struct super_block *s,
4143  u64 objectid,
4144  struct btrfs_root *root)
4145 {
4146  struct inode *inode;
4147  struct btrfs_iget_args args;
4148  args.ino = objectid;
4149  args.root = root;
4150 
4151  inode = iget5_locked(s, objectid, btrfs_find_actor,
4152  btrfs_init_locked_inode,
4153  (void *)&args);
4154  return inode;
4155 }
4156 
4157 /* Get an inode object given its location and corresponding root.
4158  * Returns in *is_new if the inode was read from disk
4159  */
4160 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
4161  struct btrfs_root *root, int *new)
4162 {
4163  struct inode *inode;
4164 
4165  inode = btrfs_iget_locked(s, location->objectid, root);
4166  if (!inode)
4167  return ERR_PTR(-ENOMEM);
4168 
4169  if (inode->i_state & I_NEW) {
4170  BTRFS_I(inode)->root = root;
4171  memcpy(&BTRFS_I(inode)->location, location, sizeof(*location));
4172  btrfs_read_locked_inode(inode);
4173  if (!is_bad_inode(inode)) {
4174  inode_tree_add(inode);
4175  unlock_new_inode(inode);
4176  if (new)
4177  *new = 1;
4178  } else {
4179  unlock_new_inode(inode);
4180  iput(inode);
4181  inode = ERR_PTR(-ESTALE);
4182  }
4183  }
4184 
4185  return inode;
4186 }
4187 
4188 static struct inode *new_simple_dir(struct super_block *s,
4189  struct btrfs_key *key,
4190  struct btrfs_root *root)
4191 {
4192  struct inode *inode = new_inode(s);
4193 
4194  if (!inode)
4195  return ERR_PTR(-ENOMEM);
4196 
4197  BTRFS_I(inode)->root = root;
4198  memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
4199  set_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags);
4200 
4202  inode->i_op = &btrfs_dir_ro_inode_operations;
4203  inode->i_fop = &simple_dir_operations;
4204  inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
4205  inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
4206 
4207  return inode;
4208 }
4209 
4210 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
4211 {
4212  struct inode *inode;
4213  struct btrfs_root *root = BTRFS_I(dir)->root;
4214  struct btrfs_root *sub_root = root;
4215  struct btrfs_key location;
4216  int index;
4217  int ret = 0;
4218 
4219  if (dentry->d_name.len > BTRFS_NAME_LEN)
4220  return ERR_PTR(-ENAMETOOLONG);
4221 
4222  if (unlikely(d_need_lookup(dentry))) {
4223  memcpy(&location, dentry->d_fsdata, sizeof(struct btrfs_key));
4224  kfree(dentry->d_fsdata);
4225  dentry->d_fsdata = NULL;
4226  /* This thing is hashed, drop it for now */
4227  d_drop(dentry);
4228  } else {
4229  ret = btrfs_inode_by_name(dir, dentry, &location);
4230  }
4231 
4232  if (ret < 0)
4233  return ERR_PTR(ret);
4234 
4235  if (location.objectid == 0)
4236  return NULL;
4237 
4238  if (location.type == BTRFS_INODE_ITEM_KEY) {
4239  inode = btrfs_iget(dir->i_sb, &location, root, NULL);
4240  return inode;
4241  }
4242 
4243  BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
4244 
4245  index = srcu_read_lock(&root->fs_info->subvol_srcu);
4246  ret = fixup_tree_root_location(root, dir, dentry,
4247  &location, &sub_root);
4248  if (ret < 0) {
4249  if (ret != -ENOENT)
4250  inode = ERR_PTR(ret);
4251  else
4252  inode = new_simple_dir(dir->i_sb, &location, sub_root);
4253  } else {
4254  inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
4255  }
4256  srcu_read_unlock(&root->fs_info->subvol_srcu, index);
4257 
4258  if (!IS_ERR(inode) && root != sub_root) {
4259  down_read(&root->fs_info->cleanup_work_sem);
4260  if (!(inode->i_sb->s_flags & MS_RDONLY))
4261  ret = btrfs_orphan_cleanup(sub_root);
4262  up_read(&root->fs_info->cleanup_work_sem);
4263  if (ret)
4264  inode = ERR_PTR(ret);
4265  }
4266 
4267  return inode;
4268 }
4269 
4270 static int btrfs_dentry_delete(const struct dentry *dentry)
4271 {
4272  struct btrfs_root *root;
4273  struct inode *inode = dentry->d_inode;
4274 
4275  if (!inode && !IS_ROOT(dentry))
4276  inode = dentry->d_parent->d_inode;
4277 
4278  if (inode) {
4279  root = BTRFS_I(inode)->root;
4280  if (btrfs_root_refs(&root->root_item) == 0)
4281  return 1;
4282 
4283  if (btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
4284  return 1;
4285  }
4286  return 0;
4287 }
4288 
4289 static void btrfs_dentry_release(struct dentry *dentry)
4290 {
4291  if (dentry->d_fsdata)
4292  kfree(dentry->d_fsdata);
4293 }
4294 
4295 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
4296  unsigned int flags)
4297 {
4298  struct dentry *ret;
4299 
4300  ret = d_splice_alias(btrfs_lookup_dentry(dir, dentry), dentry);
4301  if (unlikely(d_need_lookup(dentry))) {
4302  spin_lock(&dentry->d_lock);
4303  dentry->d_flags &= ~DCACHE_NEED_LOOKUP;
4304  spin_unlock(&dentry->d_lock);
4305  }
4306  return ret;
4307 }
4308 
4309 unsigned char btrfs_filetype_table[] = {
4311 };
4312 
4313 static int btrfs_real_readdir(struct file *filp, void *dirent,
4314  filldir_t filldir)
4315 {
4316  struct inode *inode = filp->f_dentry->d_inode;
4317  struct btrfs_root *root = BTRFS_I(inode)->root;
4318  struct btrfs_item *item;
4319  struct btrfs_dir_item *di;
4320  struct btrfs_key key;
4321  struct btrfs_key found_key;
4322  struct btrfs_path *path;
4323  struct list_head ins_list;
4324  struct list_head del_list;
4325  int ret;
4326  struct extent_buffer *leaf;
4327  int slot;
4328  unsigned char d_type;
4329  int over = 0;
4330  u32 di_cur;
4331  u32 di_total;
4332  u32 di_len;
4333  int key_type = BTRFS_DIR_INDEX_KEY;
4334  char tmp_name[32];
4335  char *name_ptr;
4336  int name_len;
4337  int is_curr = 0; /* filp->f_pos points to the current index? */
4338 
4339  /* FIXME, use a real flag for deciding about the key type */
4340  if (root->fs_info->tree_root == root)
4341  key_type = BTRFS_DIR_ITEM_KEY;
4342 
4343  /* special case for "." */
4344  if (filp->f_pos == 0) {
4345  over = filldir(dirent, ".", 1,
4346  filp->f_pos, btrfs_ino(inode), DT_DIR);
4347  if (over)
4348  return 0;
4349  filp->f_pos = 1;
4350  }
4351  /* special case for .., just use the back ref */
4352  if (filp->f_pos == 1) {
4353  u64 pino = parent_ino(filp->f_path.dentry);
4354  over = filldir(dirent, "..", 2,
4355  filp->f_pos, pino, DT_DIR);
4356  if (over)
4357  return 0;
4358  filp->f_pos = 2;
4359  }
4360  path = btrfs_alloc_path();
4361  if (!path)
4362  return -ENOMEM;
4363 
4364  path->reada = 1;
4365 
4366  if (key_type == BTRFS_DIR_INDEX_KEY) {
4367  INIT_LIST_HEAD(&ins_list);
4368  INIT_LIST_HEAD(&del_list);
4369  btrfs_get_delayed_items(inode, &ins_list, &del_list);
4370  }
4371 
4372  btrfs_set_key_type(&key, key_type);
4373  key.offset = filp->f_pos;
4374  key.objectid = btrfs_ino(inode);
4375 
4376  ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4377  if (ret < 0)
4378  goto err;
4379 
4380  while (1) {
4381  leaf = path->nodes[0];
4382  slot = path->slots[0];
4383  if (slot >= btrfs_header_nritems(leaf)) {
4384  ret = btrfs_next_leaf(root, path);
4385  if (ret < 0)
4386  goto err;
4387  else if (ret > 0)
4388  break;
4389  continue;
4390  }
4391 
4392  item = btrfs_item_nr(leaf, slot);
4393  btrfs_item_key_to_cpu(leaf, &found_key, slot);
4394 
4395  if (found_key.objectid != key.objectid)
4396  break;
4397  if (btrfs_key_type(&found_key) != key_type)
4398  break;
4399  if (found_key.offset < filp->f_pos)
4400  goto next;
4401  if (key_type == BTRFS_DIR_INDEX_KEY &&
4403  found_key.offset))
4404  goto next;
4405 
4406  filp->f_pos = found_key.offset;
4407  is_curr = 1;
4408 
4409  di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
4410  di_cur = 0;
4411  di_total = btrfs_item_size(leaf, item);
4412 
4413  while (di_cur < di_total) {
4414  struct btrfs_key location;
4415 
4416  if (verify_dir_item(root, leaf, di))
4417  break;
4418 
4419  name_len = btrfs_dir_name_len(leaf, di);
4420  if (name_len <= sizeof(tmp_name)) {
4421  name_ptr = tmp_name;
4422  } else {
4423  name_ptr = kmalloc(name_len, GFP_NOFS);
4424  if (!name_ptr) {
4425  ret = -ENOMEM;
4426  goto err;
4427  }
4428  }
4429  read_extent_buffer(leaf, name_ptr,
4430  (unsigned long)(di + 1), name_len);
4431 
4432  d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
4433  btrfs_dir_item_key_to_cpu(leaf, di, &location);
4434 
4435 
4436  /* is this a reference to our own snapshot? If so
4437  * skip it.
4438  *
4439  * In contrast to old kernels, we insert the snapshot's
4440  * dir item and dir index after it has been created, so
4441  * we won't find a reference to our own snapshot. We
4442  * still keep the following code for backward
4443  * compatibility.
4444  */
4445  if (location.type == BTRFS_ROOT_ITEM_KEY &&
4446  location.objectid == root->root_key.objectid) {
4447  over = 0;
4448  goto skip;
4449  }
4450  over = filldir(dirent, name_ptr, name_len,
4451  found_key.offset, location.objectid,
4452  d_type);
4453 
4454 skip:
4455  if (name_ptr != tmp_name)
4456  kfree(name_ptr);
4457 
4458  if (over)
4459  goto nopos;
4460  di_len = btrfs_dir_name_len(leaf, di) +
4461  btrfs_dir_data_len(leaf, di) + sizeof(*di);
4462  di_cur += di_len;
4463  di = (struct btrfs_dir_item *)((char *)di + di_len);
4464  }
4465 next:
4466  path->slots[0]++;
4467  }
4468 
4469  if (key_type == BTRFS_DIR_INDEX_KEY) {
4470  if (is_curr)
4471  filp->f_pos++;
4472  ret = btrfs_readdir_delayed_dir_index(filp, dirent, filldir,
4473  &ins_list);
4474  if (ret)
4475  goto nopos;
4476  }
4477 
4478  /* Reached end of directory/root. Bump pos past the last item. */
4479  if (key_type == BTRFS_DIR_INDEX_KEY)
4480  /*
4481  * 32-bit glibc will use getdents64, but then strtol -
4482  * so the last number we can serve is this.
4483  */
4484  filp->f_pos = 0x7fffffff;
4485  else
4486  filp->f_pos++;
4487 nopos:
4488  ret = 0;
4489 err:
4490  if (key_type == BTRFS_DIR_INDEX_KEY)
4491  btrfs_put_delayed_items(&ins_list, &del_list);
4492  btrfs_free_path(path);
4493  return ret;
4494 }
4495 
4496 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
4497 {
4498  struct btrfs_root *root = BTRFS_I(inode)->root;
4499  struct btrfs_trans_handle *trans;
4500  int ret = 0;
4501  bool nolock = false;
4502 
4503  if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
4504  return 0;
4505 
4506  if (btrfs_fs_closing(root->fs_info) && btrfs_is_free_space_inode(inode))
4507  nolock = true;
4508 
4509  if (wbc->sync_mode == WB_SYNC_ALL) {
4510  if (nolock)
4511  trans = btrfs_join_transaction_nolock(root);
4512  else
4513  trans = btrfs_join_transaction(root);
4514  if (IS_ERR(trans))
4515  return PTR_ERR(trans);
4516  ret = btrfs_commit_transaction(trans, root);
4517  }
4518  return ret;
4519 }
4520 
4521 /*
4522  * This is somewhat expensive, updating the tree every time the
4523  * inode changes. But, it is most likely to find the inode in cache.
4524  * FIXME, needs more benchmarking...there are no reasons other than performance
4525  * to keep or drop this code.
4526  */
4527 int btrfs_dirty_inode(struct inode *inode)
4528 {
4529  struct btrfs_root *root = BTRFS_I(inode)->root;
4530  struct btrfs_trans_handle *trans;
4531  int ret;
4532 
4533  if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
4534  return 0;
4535 
4536  trans = btrfs_join_transaction(root);
4537  if (IS_ERR(trans))
4538  return PTR_ERR(trans);
4539 
4540  ret = btrfs_update_inode(trans, root, inode);
4541  if (ret && ret == -ENOSPC) {
4542  /* whoops, lets try again with the full transaction */
4543  btrfs_end_transaction(trans, root);
4544  trans = btrfs_start_transaction(root, 1);
4545  if (IS_ERR(trans))
4546  return PTR_ERR(trans);
4547 
4548  ret = btrfs_update_inode(trans, root, inode);
4549  }
4550  btrfs_end_transaction(trans, root);
4551  if (BTRFS_I(inode)->delayed_node)
4553 
4554  return ret;
4555 }
4556 
4557 /*
4558  * This is a copy of file_update_time. We need this so we can return error on
4559  * ENOSPC for updating the inode in the case of file write and mmap writes.
4560  */
4561 static int btrfs_update_time(struct inode *inode, struct timespec *now,
4562  int flags)
4563 {
4564  struct btrfs_root *root = BTRFS_I(inode)->root;
4565 
4566  if (btrfs_root_readonly(root))
4567  return -EROFS;
4568 
4569  if (flags & S_VERSION)
4570  inode_inc_iversion(inode);
4571  if (flags & S_CTIME)
4572  inode->i_ctime = *now;
4573  if (flags & S_MTIME)
4574  inode->i_mtime = *now;
4575  if (flags & S_ATIME)
4576  inode->i_atime = *now;
4577  return btrfs_dirty_inode(inode);
4578 }
4579 
4580 /*
4581  * find the highest existing sequence number in a directory
4582  * and then set the in-memory index_cnt variable to reflect
4583  * free sequence numbers
4584  */
4585 static int btrfs_set_inode_index_count(struct inode *inode)
4586 {
4587  struct btrfs_root *root = BTRFS_I(inode)->root;
4588  struct btrfs_key key, found_key;
4589  struct btrfs_path *path;
4590  struct extent_buffer *leaf;
4591  int ret;
4592 
4593  key.objectid = btrfs_ino(inode);
4594  btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
4595  key.offset = (u64)-1;
4596 
4597  path = btrfs_alloc_path();
4598  if (!path)
4599  return -ENOMEM;
4600 
4601  ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4602  if (ret < 0)
4603  goto out;
4604  /* FIXME: we should be able to handle this */
4605  if (ret == 0)
4606  goto out;
4607  ret = 0;
4608 
4609  /*
4610  * MAGIC NUMBER EXPLANATION:
4611  * since we search a directory based on f_pos we have to start at 2
4612  * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
4613  * else has to start at 2
4614  */
4615  if (path->slots[0] == 0) {
4616  BTRFS_I(inode)->index_cnt = 2;
4617  goto out;
4618  }
4619 
4620  path->slots[0]--;
4621 
4622  leaf = path->nodes[0];
4623  btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4624 
4625  if (found_key.objectid != btrfs_ino(inode) ||
4626  btrfs_key_type(&found_key) != BTRFS_DIR_INDEX_KEY) {
4627  BTRFS_I(inode)->index_cnt = 2;
4628  goto out;
4629  }
4630 
4631  BTRFS_I(inode)->index_cnt = found_key.offset + 1;
4632 out:
4633  btrfs_free_path(path);
4634  return ret;
4635 }
4636 
4637 /*
4638  * helper to find a free sequence number in a given directory. This current
4639  * code is very simple, later versions will do smarter things in the btree
4640  */
4641 int btrfs_set_inode_index(struct inode *dir, u64 *index)
4642 {
4643  int ret = 0;
4644 
4645  if (BTRFS_I(dir)->index_cnt == (u64)-1) {
4647  if (ret) {
4648  ret = btrfs_set_inode_index_count(dir);
4649  if (ret)
4650  return ret;
4651  }
4652  }
4653 
4654  *index = BTRFS_I(dir)->index_cnt;
4655  BTRFS_I(dir)->index_cnt++;
4656 
4657  return ret;
4658 }
4659 
4660 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
4661  struct btrfs_root *root,
4662  struct inode *dir,
4663  const char *name, int name_len,
4664  u64 ref_objectid, u64 objectid,
4665  umode_t mode, u64 *index)
4666 {
4667  struct inode *inode;
4668  struct btrfs_inode_item *inode_item;
4669  struct btrfs_key *location;
4670  struct btrfs_path *path;
4671  struct btrfs_inode_ref *ref;
4672  struct btrfs_key key[2];
4673  u32 sizes[2];
4674  unsigned long ptr;
4675  int ret;
4676  int owner;
4677 
4678  path = btrfs_alloc_path();
4679  if (!path)
4680  return ERR_PTR(-ENOMEM);
4681 
4682  inode = new_inode(root->fs_info->sb);
4683  if (!inode) {
4684  btrfs_free_path(path);
4685  return ERR_PTR(-ENOMEM);
4686  }
4687 
4688  /*
4689  * we have to initialize this early, so we can reclaim the inode
4690  * number if we fail afterwards in this function.
4691  */
4692  inode->i_ino = objectid;
4693 
4694  if (dir) {
4695  trace_btrfs_inode_request(dir);
4696 
4697  ret = btrfs_set_inode_index(dir, index);
4698  if (ret) {
4699  btrfs_free_path(path);
4700  iput(inode);
4701  return ERR_PTR(ret);
4702  }
4703  }
4704  /*
4705  * index_cnt is ignored for everything but a dir,
4706  * btrfs_get_inode_index_count has an explanation for the magic
4707  * number
4708  */
4709  BTRFS_I(inode)->index_cnt = 2;
4710  BTRFS_I(inode)->root = root;
4711  BTRFS_I(inode)->generation = trans->transid;
4712  inode->i_generation = BTRFS_I(inode)->generation;
4713 
4714  /*
4715  * We could have gotten an inode number from somebody who was fsynced
4716  * and then removed in this same transaction, so let's just set full
4717  * sync since it will be a full sync anyway and this will blow away the
4718  * old info in the log.
4719  */
4720  set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
4721 
4722  if (S_ISDIR(mode))
4723  owner = 0;
4724  else
4725  owner = 1;
4726 
4727  key[0].objectid = objectid;
4728  btrfs_set_key_type(&key[0], BTRFS_INODE_ITEM_KEY);
4729  key[0].offset = 0;
4730 
4731  /*
4732  * Start new inodes with an inode_ref. This is slightly more
4733  * efficient for small numbers of hard links since they will
4734  * be packed into one item. Extended refs will kick in if we
4735  * add more hard links than can fit in the ref item.
4736  */
4737  key[1].objectid = objectid;
4738  btrfs_set_key_type(&key[1], BTRFS_INODE_REF_KEY);
4739  key[1].offset = ref_objectid;
4740 
4741  sizes[0] = sizeof(struct btrfs_inode_item);
4742  sizes[1] = name_len + sizeof(*ref);
4743 
4744  path->leave_spinning = 1;
4745  ret = btrfs_insert_empty_items(trans, root, path, key, sizes, 2);
4746  if (ret != 0)
4747  goto fail;
4748 
4749  inode_init_owner(inode, dir, mode);
4750  inode_set_bytes(inode, 0);
4751  inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
4752  inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
4753  struct btrfs_inode_item);
4754  memset_extent_buffer(path->nodes[0], 0, (unsigned long)inode_item,
4755  sizeof(*inode_item));
4756  fill_inode_item(trans, path->nodes[0], inode_item, inode);
4757 
4758  ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
4759  struct btrfs_inode_ref);
4760  btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
4761  btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
4762  ptr = (unsigned long)(ref + 1);
4763  write_extent_buffer(path->nodes[0], name, ptr, name_len);
4764 
4765  btrfs_mark_buffer_dirty(path->nodes[0]);
4766  btrfs_free_path(path);
4767 
4768  location = &BTRFS_I(inode)->location;
4769  location->objectid = objectid;
4770  location->offset = 0;
4771  btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
4772 
4773  btrfs_inherit_iflags(inode, dir);
4774 
4775  if (S_ISREG(mode)) {
4776  if (btrfs_test_opt(root, NODATASUM))
4777  BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
4778  if (btrfs_test_opt(root, NODATACOW) ||
4779  (BTRFS_I(dir)->flags & BTRFS_INODE_NODATACOW))
4780  BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW;
4781  }
4782 
4783  insert_inode_hash(inode);
4784  inode_tree_add(inode);
4785 
4786  trace_btrfs_inode_new(inode);
4787  btrfs_set_inode_last_trans(trans, inode);
4788 
4789  btrfs_update_root_times(trans, root);
4790 
4791  return inode;
4792 fail:
4793  if (dir)
4794  BTRFS_I(dir)->index_cnt--;
4795  btrfs_free_path(path);
4796  iput(inode);
4797  return ERR_PTR(ret);
4798 }
4799 
4800 static inline u8 btrfs_inode_type(struct inode *inode)
4801 {
4802  return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
4803 }
4804 
4805 /*
4806  * utility function to add 'inode' into 'parent_inode' with
4807  * a give name and a given sequence number.
4808  * if 'add_backref' is true, also insert a backref from the
4809  * inode to the parent directory.
4810  */
4812  struct inode *parent_inode, struct inode *inode,
4813  const char *name, int name_len, int add_backref, u64 index)
4814 {
4815  int ret = 0;
4816  struct btrfs_key key;
4817  struct btrfs_root *root = BTRFS_I(parent_inode)->root;
4818  u64 ino = btrfs_ino(inode);
4819  u64 parent_ino = btrfs_ino(parent_inode);
4820 
4821  if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
4822  memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
4823  } else {
4824  key.objectid = ino;
4825  btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
4826  key.offset = 0;
4827  }
4828 
4829  if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
4830  ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
4831  key.objectid, root->root_key.objectid,
4832  parent_ino, index, name, name_len);
4833  } else if (add_backref) {
4834  ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
4835  parent_ino, index);
4836  }
4837 
4838  /* Nothing to clean up yet */
4839  if (ret)
4840  return ret;
4841 
4842  ret = btrfs_insert_dir_item(trans, root, name, name_len,
4843  parent_inode, &key,
4844  btrfs_inode_type(inode), index);
4845  if (ret == -EEXIST)
4846  goto fail_dir_item;
4847  else if (ret) {
4848  btrfs_abort_transaction(trans, root, ret);
4849  return ret;
4850  }
4851 
4852  btrfs_i_size_write(parent_inode, parent_inode->i_size +
4853  name_len * 2);
4854  inode_inc_iversion(parent_inode);
4855  parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
4856  ret = btrfs_update_inode(trans, root, parent_inode);
4857  if (ret)
4858  btrfs_abort_transaction(trans, root, ret);
4859  return ret;
4860 
4861 fail_dir_item:
4862  if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
4863  u64 local_index;
4864  int err;
4865  err = btrfs_del_root_ref(trans, root->fs_info->tree_root,
4866  key.objectid, root->root_key.objectid,
4867  parent_ino, &local_index, name, name_len);
4868 
4869  } else if (add_backref) {
4870  u64 local_index;
4871  int err;
4872 
4873  err = btrfs_del_inode_ref(trans, root, name, name_len,
4874  ino, parent_ino, &local_index);
4875  }
4876  return ret;
4877 }
4878 
4879 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
4880  struct inode *dir, struct dentry *dentry,
4881  struct inode *inode, int backref, u64 index)
4882 {
4883  int err = btrfs_add_link(trans, dir, inode,
4884  dentry->d_name.name, dentry->d_name.len,
4885  backref, index);
4886  if (err > 0)
4887  err = -EEXIST;
4888  return err;
4889 }
4890 
4891 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
4892  umode_t mode, dev_t rdev)
4893 {
4894  struct btrfs_trans_handle *trans;
4895  struct btrfs_root *root = BTRFS_I(dir)->root;
4896  struct inode *inode = NULL;
4897  int err;
4898  int drop_inode = 0;
4899  u64 objectid;
4900  unsigned long nr = 0;
4901  u64 index = 0;
4902 
4903  if (!new_valid_dev(rdev))
4904  return -EINVAL;
4905 
4906  /*
4907  * 2 for inode item and ref
4908  * 2 for dir items
4909  * 1 for xattr if selinux is on
4910  */
4911  trans = btrfs_start_transaction(root, 5);
4912  if (IS_ERR(trans))
4913  return PTR_ERR(trans);
4914 
4915  err = btrfs_find_free_ino(root, &objectid);
4916  if (err)
4917  goto out_unlock;
4918 
4919  inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4920  dentry->d_name.len, btrfs_ino(dir), objectid,
4921  mode, &index);
4922  if (IS_ERR(inode)) {
4923  err = PTR_ERR(inode);
4924  goto out_unlock;
4925  }
4926 
4927  err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
4928  if (err) {
4929  drop_inode = 1;
4930  goto out_unlock;
4931  }
4932 
4933  /*
4934  * If the active LSM wants to access the inode during
4935  * d_instantiate it needs these. Smack checks to see
4936  * if the filesystem supports xattrs by looking at the
4937  * ops vector.
4938  */
4939 
4940  inode->i_op = &btrfs_special_inode_operations;
4941  err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
4942  if (err)
4943  drop_inode = 1;
4944  else {
4945  init_special_inode(inode, inode->i_mode, rdev);
4946  btrfs_update_inode(trans, root, inode);
4947  d_instantiate(dentry, inode);
4948  }
4949 out_unlock:
4950  nr = trans->blocks_used;
4951  btrfs_end_transaction(trans, root);
4952  btrfs_btree_balance_dirty(root, nr);
4953  if (drop_inode) {
4954  inode_dec_link_count(inode);
4955  iput(inode);
4956  }
4957  return err;
4958 }
4959 
4960 static int btrfs_create(struct inode *dir, struct dentry *dentry,
4961  umode_t mode, bool excl)
4962 {
4963  struct btrfs_trans_handle *trans;
4964  struct btrfs_root *root = BTRFS_I(dir)->root;
4965  struct inode *inode = NULL;
4966  int drop_inode = 0;
4967  int err;
4968  unsigned long nr = 0;
4969  u64 objectid;
4970  u64 index = 0;
4971 
4972  /*
4973  * 2 for inode item and ref
4974  * 2 for dir items
4975  * 1 for xattr if selinux is on
4976  */
4977  trans = btrfs_start_transaction(root, 5);
4978  if (IS_ERR(trans))
4979  return PTR_ERR(trans);
4980 
4981  err = btrfs_find_free_ino(root, &objectid);
4982  if (err)
4983  goto out_unlock;
4984 
4985  inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4986  dentry->d_name.len, btrfs_ino(dir), objectid,
4987  mode, &index);
4988  if (IS_ERR(inode)) {
4989  err = PTR_ERR(inode);
4990  goto out_unlock;
4991  }
4992 
4993  err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
4994  if (err) {
4995  drop_inode = 1;
4996  goto out_unlock;
4997  }
4998 
4999  /*
5000  * If the active LSM wants to access the inode during
5001  * d_instantiate it needs these. Smack checks to see
5002  * if the filesystem supports xattrs by looking at the
5003  * ops vector.
5004  */
5005  inode->i_fop = &btrfs_file_operations;
5006  inode->i_op = &btrfs_file_inode_operations;
5007 
5008  err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
5009  if (err)
5010  drop_inode = 1;
5011  else {
5012  inode->i_mapping->a_ops = &btrfs_aops;
5013  inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
5014  BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
5015  d_instantiate(dentry, inode);
5016  }
5017 out_unlock:
5018  nr = trans->blocks_used;
5019  btrfs_end_transaction(trans, root);
5020  if (drop_inode) {
5021  inode_dec_link_count(inode);
5022  iput(inode);
5023  }
5024  btrfs_btree_balance_dirty(root, nr);
5025  return err;
5026 }
5027 
5028 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
5029  struct dentry *dentry)
5030 {
5031  struct btrfs_trans_handle *trans;
5032  struct btrfs_root *root = BTRFS_I(dir)->root;
5033  struct inode *inode = old_dentry->d_inode;
5034  u64 index;
5035  unsigned long nr = 0;
5036  int err;
5037  int drop_inode = 0;
5038 
5039  /* do not allow sys_link's with other subvols of the same device */
5040  if (root->objectid != BTRFS_I(inode)->root->objectid)
5041  return -EXDEV;
5042 
5043  if (inode->i_nlink >= BTRFS_LINK_MAX)
5044  return -EMLINK;
5045 
5046  err = btrfs_set_inode_index(dir, &index);
5047  if (err)
5048  goto fail;
5049 
5050  /*
5051  * 2 items for inode and inode ref
5052  * 2 items for dir items
5053  * 1 item for parent inode
5054  */
5055  trans = btrfs_start_transaction(root, 5);
5056  if (IS_ERR(trans)) {
5057  err = PTR_ERR(trans);
5058  goto fail;
5059  }
5060 
5061  btrfs_inc_nlink(inode);
5062  inode_inc_iversion(inode);
5063  inode->i_ctime = CURRENT_TIME;
5064  ihold(inode);
5065 
5066  err = btrfs_add_nondir(trans, dir, dentry, inode, 1, index);
5067 
5068  if (err) {
5069  drop_inode = 1;
5070  } else {
5071  struct dentry *parent = dentry->d_parent;
5072  err = btrfs_update_inode(trans, root, inode);
5073  if (err)
5074  goto fail;
5075  d_instantiate(dentry, inode);
5076  btrfs_log_new_name(trans, inode, NULL, parent);
5077  }
5078 
5079  nr = trans->blocks_used;
5080  btrfs_end_transaction(trans, root);
5081 fail:
5082  if (drop_inode) {
5083  inode_dec_link_count(inode);
5084  iput(inode);
5085  }
5086  btrfs_btree_balance_dirty(root, nr);
5087  return err;
5088 }
5089 
5090 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
5091 {
5092  struct inode *inode = NULL;
5093  struct btrfs_trans_handle *trans;
5094  struct btrfs_root *root = BTRFS_I(dir)->root;
5095  int err = 0;
5096  int drop_on_err = 0;
5097  u64 objectid = 0;
5098  u64 index = 0;
5099  unsigned long nr = 1;
5100 
5101  /*
5102  * 2 items for inode and ref
5103  * 2 items for dir items
5104  * 1 for xattr if selinux is on
5105  */
5106  trans = btrfs_start_transaction(root, 5);
5107  if (IS_ERR(trans))
5108  return PTR_ERR(trans);
5109 
5110  err = btrfs_find_free_ino(root, &objectid);
5111  if (err)
5112  goto out_fail;
5113 
5114  inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
5115  dentry->d_name.len, btrfs_ino(dir), objectid,
5116  S_IFDIR | mode, &index);
5117  if (IS_ERR(inode)) {
5118  err = PTR_ERR(inode);
5119  goto out_fail;
5120  }
5121 
5122  drop_on_err = 1;
5123 
5124  err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
5125  if (err)
5126  goto out_fail;
5127 
5128  inode->i_op = &btrfs_dir_inode_operations;
5129  inode->i_fop = &btrfs_dir_file_operations;
5130 
5131  btrfs_i_size_write(inode, 0);
5132  err = btrfs_update_inode(trans, root, inode);
5133  if (err)
5134  goto out_fail;
5135 
5136  err = btrfs_add_link(trans, dir, inode, dentry->d_name.name,
5137  dentry->d_name.len, 0, index);
5138  if (err)
5139  goto out_fail;
5140 
5141  d_instantiate(dentry, inode);
5142  drop_on_err = 0;
5143 
5144 out_fail:
5145  nr = trans->blocks_used;
5146  btrfs_end_transaction(trans, root);
5147  if (drop_on_err)
5148  iput(inode);
5149  btrfs_btree_balance_dirty(root, nr);
5150  return err;
5151 }
5152 
5153 /* helper for btfs_get_extent. Given an existing extent in the tree,
5154  * and an extent that you want to insert, deal with overlap and insert
5155  * the new extent into the tree.
5156  */
5157 static int merge_extent_mapping(struct extent_map_tree *em_tree,
5158  struct extent_map *existing,
5159  struct extent_map *em,
5160  u64 map_start, u64 map_len)
5161 {
5162  u64 start_diff;
5163 
5164  BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
5165  start_diff = map_start - em->start;
5166  em->start = map_start;
5167  em->len = map_len;
5168  if (em->block_start < EXTENT_MAP_LAST_BYTE &&
5170  em->block_start += start_diff;
5171  em->block_len -= start_diff;
5172  }
5173  return add_extent_mapping(em_tree, em);
5174 }
5175 
5176 static noinline int uncompress_inline(struct btrfs_path *path,
5177  struct inode *inode, struct page *page,
5178  size_t pg_offset, u64 extent_offset,
5179  struct btrfs_file_extent_item *item)
5180 {
5181  int ret;
5182  struct extent_buffer *leaf = path->nodes[0];
5183  char *tmp;
5184  size_t max_size;
5185  unsigned long inline_size;
5186  unsigned long ptr;
5187  int compress_type;
5188 
5189  WARN_ON(pg_offset != 0);
5190  compress_type = btrfs_file_extent_compression(leaf, item);
5191  max_size = btrfs_file_extent_ram_bytes(leaf, item);
5192  inline_size = btrfs_file_extent_inline_item_len(leaf,
5193  btrfs_item_nr(leaf, path->slots[0]));
5194  tmp = kmalloc(inline_size, GFP_NOFS);
5195  if (!tmp)
5196  return -ENOMEM;
5197  ptr = btrfs_file_extent_inline_start(item);
5198 
5199  read_extent_buffer(leaf, tmp, ptr, inline_size);
5200 
5201  max_size = min_t(unsigned long, PAGE_CACHE_SIZE, max_size);
5202  ret = btrfs_decompress(compress_type, tmp, page,
5203  extent_offset, inline_size, max_size);
5204  if (ret) {
5205  char *kaddr = kmap_atomic(page);
5206  unsigned long copy_size = min_t(u64,
5207  PAGE_CACHE_SIZE - pg_offset,
5208  max_size - extent_offset);
5209  memset(kaddr + pg_offset, 0, copy_size);
5210  kunmap_atomic(kaddr);
5211  }
5212  kfree(tmp);
5213  return 0;
5214 }
5215 
5216 /*
5217  * a bit scary, this does extent mapping from logical file offset to the disk.
5218  * the ugly parts come from merging extents from the disk with the in-ram
5219  * representation. This gets more complex because of the data=ordered code,
5220  * where the in-ram extents might be locked pending data=ordered completion.
5221  *
5222  * This also copies inline extents directly into the page.
5223  */
5224 
5225 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
5226  size_t pg_offset, u64 start, u64 len,
5227  int create)
5228 {
5229  int ret;
5230  int err = 0;
5231  u64 bytenr;
5232  u64 extent_start = 0;
5233  u64 extent_end = 0;
5234  u64 objectid = btrfs_ino(inode);
5235  u32 found_type;
5236  struct btrfs_path *path = NULL;
5237  struct btrfs_root *root = BTRFS_I(inode)->root;
5238  struct btrfs_file_extent_item *item;
5239  struct extent_buffer *leaf;
5240  struct btrfs_key found_key;
5241  struct extent_map *em = NULL;
5242  struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
5243  struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
5244  struct btrfs_trans_handle *trans = NULL;
5245  int compress_type;
5246 
5247 again:
5248  read_lock(&em_tree->lock);
5249  em = lookup_extent_mapping(em_tree, start, len);
5250  if (em)
5251  em->bdev = root->fs_info->fs_devices->latest_bdev;
5252  read_unlock(&em_tree->lock);
5253 
5254  if (em) {
5255  if (em->start > start || em->start + em->len <= start)
5256  free_extent_map(em);
5257  else if (em->block_start == EXTENT_MAP_INLINE && page)
5258  free_extent_map(em);
5259  else
5260  goto out;
5261  }
5262  em = alloc_extent_map();
5263  if (!em) {
5264  err = -ENOMEM;
5265  goto out;
5266  }
5267  em->bdev = root->fs_info->fs_devices->latest_bdev;
5268  em->start = EXTENT_MAP_HOLE;
5270  em->len = (u64)-1;
5271  em->block_len = (u64)-1;
5272 
5273  if (!path) {
5274  path = btrfs_alloc_path();
5275  if (!path) {
5276  err = -ENOMEM;
5277  goto out;
5278  }
5279  /*
5280  * Chances are we'll be called again, so go ahead and do
5281  * readahead
5282  */
5283  path->reada = 1;
5284  }
5285 
5286  ret = btrfs_lookup_file_extent(trans, root, path,
5287  objectid, start, trans != NULL);
5288  if (ret < 0) {
5289  err = ret;
5290  goto out;
5291  }
5292 
5293  if (ret != 0) {
5294  if (path->slots[0] == 0)
5295  goto not_found;
5296  path->slots[0]--;
5297  }
5298 
5299  leaf = path->nodes[0];
5300  item = btrfs_item_ptr(leaf, path->slots[0],
5301  struct btrfs_file_extent_item);
5302  /* are we inside the extent that was found? */
5303  btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5304  found_type = btrfs_key_type(&found_key);
5305  if (found_key.objectid != objectid ||
5306  found_type != BTRFS_EXTENT_DATA_KEY) {
5307  goto not_found;
5308  }
5309 
5310  found_type = btrfs_file_extent_type(leaf, item);
5311  extent_start = found_key.offset;
5312  compress_type = btrfs_file_extent_compression(leaf, item);
5313  if (found_type == BTRFS_FILE_EXTENT_REG ||
5314  found_type == BTRFS_FILE_EXTENT_PREALLOC) {
5315  extent_end = extent_start +
5316  btrfs_file_extent_num_bytes(leaf, item);
5317  } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
5318  size_t size;
5319  size = btrfs_file_extent_inline_len(leaf, item);
5320  extent_end = (extent_start + size + root->sectorsize - 1) &
5321  ~((u64)root->sectorsize - 1);
5322  }
5323 
5324  if (start >= extent_end) {
5325  path->slots[0]++;
5326  if (path->slots[0] >= btrfs_header_nritems(leaf)) {
5327  ret = btrfs_next_leaf(root, path);
5328  if (ret < 0) {
5329  err = ret;
5330  goto out;
5331  }
5332  if (ret > 0)
5333  goto not_found;
5334  leaf = path->nodes[0];
5335  }
5336  btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5337  if (found_key.objectid != objectid ||
5338  found_key.type != BTRFS_EXTENT_DATA_KEY)
5339  goto not_found;
5340  if (start + len <= found_key.offset)
5341  goto not_found;
5342  em->start = start;
5343  em->len = found_key.offset - start;
5344  goto not_found_em;
5345  }
5346 
5347  if (found_type == BTRFS_FILE_EXTENT_REG ||
5348  found_type == BTRFS_FILE_EXTENT_PREALLOC) {
5349  em->start = extent_start;
5350  em->len = extent_end - extent_start;
5351  em->orig_start = extent_start -
5352  btrfs_file_extent_offset(leaf, item);
5353  bytenr = btrfs_file_extent_disk_bytenr(leaf, item);
5354  if (bytenr == 0) {
5356  goto insert;
5357  }
5358  if (compress_type != BTRFS_COMPRESS_NONE) {
5360  em->compress_type = compress_type;
5361  em->block_start = bytenr;
5362  em->block_len = btrfs_file_extent_disk_num_bytes(leaf,
5363  item);
5364  } else {
5365  bytenr += btrfs_file_extent_offset(leaf, item);
5366  em->block_start = bytenr;
5367  em->block_len = em->len;
5368  if (found_type == BTRFS_FILE_EXTENT_PREALLOC)
5370  }
5371  goto insert;
5372  } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
5373  unsigned long ptr;
5374  char *map;
5375  size_t size;
5376  size_t extent_offset;
5377  size_t copy_size;
5378 
5380  if (!page || create) {
5381  em->start = extent_start;
5382  em->len = extent_end - extent_start;
5383  goto out;
5384  }
5385 
5386  size = btrfs_file_extent_inline_len(leaf, item);
5387  extent_offset = page_offset(page) + pg_offset - extent_start;
5388  copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
5389  size - extent_offset);
5390  em->start = extent_start + extent_offset;
5391  em->len = (copy_size + root->sectorsize - 1) &
5392  ~((u64)root->sectorsize - 1);
5394  if (compress_type) {
5396  em->compress_type = compress_type;
5397  }
5398  ptr = btrfs_file_extent_inline_start(item) + extent_offset;
5399  if (create == 0 && !PageUptodate(page)) {
5400  if (btrfs_file_extent_compression(leaf, item) !=
5402  ret = uncompress_inline(path, inode, page,
5403  pg_offset,
5404  extent_offset, item);
5405  BUG_ON(ret); /* -ENOMEM */
5406  } else {
5407  map = kmap(page);
5408  read_extent_buffer(leaf, map + pg_offset, ptr,
5409  copy_size);
5410  if (pg_offset + copy_size < PAGE_CACHE_SIZE) {
5411  memset(map + pg_offset + copy_size, 0,
5412  PAGE_CACHE_SIZE - pg_offset -
5413  copy_size);
5414  }
5415  kunmap(page);
5416  }
5417  flush_dcache_page(page);
5418  } else if (create && PageUptodate(page)) {
5419  BUG();
5420  if (!trans) {
5421  kunmap(page);
5422  free_extent_map(em);
5423  em = NULL;
5424 
5425  btrfs_release_path(path);
5426  trans = btrfs_join_transaction(root);
5427 
5428  if (IS_ERR(trans))
5429  return ERR_CAST(trans);
5430  goto again;
5431  }
5432  map = kmap(page);
5433  write_extent_buffer(leaf, map + pg_offset, ptr,
5434  copy_size);
5435  kunmap(page);
5437  }
5438  set_extent_uptodate(io_tree, em->start,
5439  extent_map_end(em) - 1, NULL, GFP_NOFS);
5440  goto insert;
5441  } else {
5442  printk(KERN_ERR "btrfs unknown found_type %d\n", found_type);
5443  WARN_ON(1);
5444  }
5445 not_found:
5446  em->start = start;
5447  em->len = len;
5448 not_found_em:
5451 insert:
5452  btrfs_release_path(path);
5453  if (em->start > start || extent_map_end(em) <= start) {
5454  printk(KERN_ERR "Btrfs: bad extent! em: [%llu %llu] passed "
5455  "[%llu %llu]\n", (unsigned long long)em->start,
5456  (unsigned long long)em->len,
5457  (unsigned long long)start,
5458  (unsigned long long)len);
5459  err = -EIO;
5460  goto out;
5461  }
5462 
5463  err = 0;
5464  write_lock(&em_tree->lock);
5465  ret = add_extent_mapping(em_tree, em);
5466  /* it is possible that someone inserted the extent into the tree
5467  * while we had the lock dropped. It is also possible that
5468  * an overlapping map exists in the tree
5469  */
5470  if (ret == -EEXIST) {
5471  struct extent_map *existing;
5472 
5473  ret = 0;
5474 
5475  existing = lookup_extent_mapping(em_tree, start, len);
5476  if (existing && (existing->start > start ||
5477  existing->start + existing->len <= start)) {
5478  free_extent_map(existing);
5479  existing = NULL;
5480  }
5481  if (!existing) {
5482  existing = lookup_extent_mapping(em_tree, em->start,
5483  em->len);
5484  if (existing) {
5485  err = merge_extent_mapping(em_tree, existing,
5486  em, start,
5487  root->sectorsize);
5488  free_extent_map(existing);
5489  if (err) {
5490  free_extent_map(em);
5491  em = NULL;
5492  }
5493  } else {
5494  err = -EIO;
5495  free_extent_map(em);
5496  em = NULL;
5497  }
5498  } else {
5499  free_extent_map(em);
5500  em = existing;
5501  err = 0;
5502  }
5503  }
5504  write_unlock(&em_tree->lock);
5505 out:
5506 
5507  if (em)
5508  trace_btrfs_get_extent(root, em);
5509 
5510  if (path)
5511  btrfs_free_path(path);
5512  if (trans) {
5513  ret = btrfs_end_transaction(trans, root);
5514  if (!err)
5515  err = ret;
5516  }
5517  if (err) {
5518  free_extent_map(em);
5519  return ERR_PTR(err);
5520  }
5521  BUG_ON(!em); /* Error is always set */
5522  return em;
5523 }
5524 
5525 struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
5526  size_t pg_offset, u64 start, u64 len,
5527  int create)
5528 {
5529  struct extent_map *em;
5530  struct extent_map *hole_em = NULL;
5531  u64 range_start = start;
5532  u64 end;
5533  u64 found;
5534  u64 found_end;
5535  int err = 0;
5536 
5537  em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
5538  if (IS_ERR(em))
5539  return em;
5540  if (em) {
5541  /*
5542  * if our em maps to a hole, there might
5543  * actually be delalloc bytes behind it
5544  */
5545  if (em->block_start != EXTENT_MAP_HOLE)
5546  return em;
5547  else
5548  hole_em = em;
5549  }
5550 
5551  /* check to see if we've wrapped (len == -1 or similar) */
5552  end = start + len;
5553  if (end < start)
5554  end = (u64)-1;
5555  else
5556  end -= 1;
5557 
5558  em = NULL;
5559 
5560  /* ok, we didn't find anything, lets look for delalloc */
5561  found = count_range_bits(&BTRFS_I(inode)->io_tree, &range_start,
5562  end, len, EXTENT_DELALLOC, 1);
5563  found_end = range_start + found;
5564  if (found_end < range_start)
5565  found_end = (u64)-1;
5566 
5567  /*
5568  * we didn't find anything useful, return
5569  * the original results from get_extent()
5570  */
5571  if (range_start > end || found_end <= start) {
5572  em = hole_em;
5573  hole_em = NULL;
5574  goto out;
5575  }
5576 
5577  /* adjust the range_start to make sure it doesn't
5578  * go backwards from the start they passed in
5579  */
5580  range_start = max(start,range_start);
5581  found = found_end - range_start;
5582 
5583  if (found > 0) {
5584  u64 hole_start = start;
5585  u64 hole_len = len;
5586 
5587  em = alloc_extent_map();
5588  if (!em) {
5589  err = -ENOMEM;
5590  goto out;
5591  }
5592  /*
5593  * when btrfs_get_extent can't find anything it
5594  * returns one huge hole
5595  *
5596  * make sure what it found really fits our range, and
5597  * adjust to make sure it is based on the start from
5598  * the caller
5599  */
5600  if (hole_em) {
5601  u64 calc_end = extent_map_end(hole_em);
5602 
5603  if (calc_end <= start || (hole_em->start > end)) {
5604  free_extent_map(hole_em);
5605  hole_em = NULL;
5606  } else {
5607  hole_start = max(hole_em->start, start);
5608  hole_len = calc_end - hole_start;
5609  }
5610  }
5611  em->bdev = NULL;
5612  if (hole_em && range_start > hole_start) {
5613  /* our hole starts before our delalloc, so we
5614  * have to return just the parts of the hole
5615  * that go until the delalloc starts
5616  */
5617  em->len = min(hole_len,
5618  range_start - hole_start);
5619  em->start = hole_start;
5620  em->orig_start = hole_start;
5621  /*
5622  * don't adjust block start at all,
5623  * it is fixed at EXTENT_MAP_HOLE
5624  */
5625  em->block_start = hole_em->block_start;
5626  em->block_len = hole_len;
5627  } else {
5628  em->start = range_start;
5629  em->len = found;
5630  em->orig_start = range_start;
5632  em->block_len = found;
5633  }
5634  } else if (hole_em) {
5635  return hole_em;
5636  }
5637 out:
5638 
5639  free_extent_map(hole_em);
5640  if (err) {
5641  free_extent_map(em);
5642  return ERR_PTR(err);
5643  }
5644  return em;
5645 }
5646 
5647 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
5648  struct extent_map *em,
5649  u64 start, u64 len)
5650 {
5651  struct btrfs_root *root = BTRFS_I(inode)->root;
5652  struct btrfs_trans_handle *trans;
5653  struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
5654  struct btrfs_key ins;
5655  u64 alloc_hint;
5656  int ret;
5657  bool insert = false;
5658 
5659  /*
5660  * Ok if the extent map we looked up is a hole and is for the exact
5661  * range we want, there is no reason to allocate a new one, however if
5662  * it is not right then we need to free this one and drop the cache for
5663  * our range.
5664  */
5665  if (em->block_start != EXTENT_MAP_HOLE || em->start != start ||
5666  em->len != len) {
5667  free_extent_map(em);
5668  em = NULL;
5669  insert = true;
5670  btrfs_drop_extent_cache(inode, start, start + len - 1, 0);
5671  }
5672 
5673  trans = btrfs_join_transaction(root);
5674  if (IS_ERR(trans))
5675  return ERR_CAST(trans);
5676 
5677  if (start <= BTRFS_I(inode)->disk_i_size && len < 64 * 1024)
5678  btrfs_add_inode_defrag(trans, inode);
5679 
5680  trans->block_rsv = &root->fs_info->delalloc_block_rsv;
5681 
5682  alloc_hint = get_extent_allocation_hint(inode, start, len);
5683  ret = btrfs_reserve_extent(trans, root, len, root->sectorsize, 0,
5684  alloc_hint, &ins, 1);
5685  if (ret) {
5686  em = ERR_PTR(ret);
5687  goto out;
5688  }
5689 
5690  if (!em) {
5691  em = alloc_extent_map();
5692  if (!em) {
5693  em = ERR_PTR(-ENOMEM);
5694  goto out;
5695  }
5696  }
5697 
5698  em->start = start;
5699  em->orig_start = em->start;
5700  em->len = ins.offset;
5701 
5702  em->block_start = ins.objectid;
5703  em->block_len = ins.offset;
5704  em->bdev = root->fs_info->fs_devices->latest_bdev;
5705 
5706  /*
5707  * We need to do this because if we're using the original em we searched
5708  * for, we could have EXTENT_FLAG_VACANCY set, and we don't want that.
5709  */
5710  em->flags = 0;
5712 
5713  while (insert) {
5714  write_lock(&em_tree->lock);
5715  ret = add_extent_mapping(em_tree, em);
5716  write_unlock(&em_tree->lock);
5717  if (ret != -EEXIST)
5718  break;
5719  btrfs_drop_extent_cache(inode, start, start + em->len - 1, 0);
5720  }
5721 
5722  ret = btrfs_add_ordered_extent_dio(inode, start, ins.objectid,
5723  ins.offset, ins.offset, 0);
5724  if (ret) {
5725  btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
5726  em = ERR_PTR(ret);
5727  }
5728 out:
5729  btrfs_end_transaction(trans, root);
5730  return em;
5731 }
5732 
5733 /*
5734  * returns 1 when the nocow is safe, < 1 on error, 0 if the
5735  * block must be cow'd
5736  */
5737 static noinline int can_nocow_odirect(struct btrfs_trans_handle *trans,
5738  struct inode *inode, u64 offset, u64 len)
5739 {
5740  struct btrfs_path *path;
5741  int ret;
5742  struct extent_buffer *leaf;
5743  struct btrfs_root *root = BTRFS_I(inode)->root;
5744  struct btrfs_file_extent_item *fi;
5745  struct btrfs_key key;
5746  u64 disk_bytenr;
5747  u64 backref_offset;
5748  u64 extent_end;
5749  u64 num_bytes;
5750  int slot;
5751  int found_type;
5752 
5753  path = btrfs_alloc_path();
5754  if (!path)
5755  return -ENOMEM;
5756 
5757  ret = btrfs_lookup_file_extent(trans, root, path, btrfs_ino(inode),
5758  offset, 0);
5759  if (ret < 0)
5760  goto out;
5761 
5762  slot = path->slots[0];
5763  if (ret == 1) {
5764  if (slot == 0) {
5765  /* can't find the item, must cow */
5766  ret = 0;
5767  goto out;
5768  }
5769  slot--;
5770  }
5771  ret = 0;
5772  leaf = path->nodes[0];
5773  btrfs_item_key_to_cpu(leaf, &key, slot);
5774  if (key.objectid != btrfs_ino(inode) ||
5775  key.type != BTRFS_EXTENT_DATA_KEY) {
5776  /* not our file or wrong item type, must cow */
5777  goto out;
5778  }
5779 
5780  if (key.offset > offset) {
5781  /* Wrong offset, must cow */
5782  goto out;
5783  }
5784 
5785  fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
5786  found_type = btrfs_file_extent_type(leaf, fi);
5787  if (found_type != BTRFS_FILE_EXTENT_REG &&
5788  found_type != BTRFS_FILE_EXTENT_PREALLOC) {
5789  /* not a regular extent, must cow */
5790  goto out;
5791  }
5792  disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
5793  backref_offset = btrfs_file_extent_offset(leaf, fi);
5794 
5795  extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
5796  if (extent_end < offset + len) {
5797  /* extent doesn't include our full range, must cow */
5798  goto