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TOMOYO Linux Cross Reference
Linux/fs/btrfs/tree-log.c

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  1 /*
  2  * Copyright (C) 2008 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/sched.h>
 20 #include <linux/slab.h>
 21 #include "ctree.h"
 22 #include "transaction.h"
 23 #include "disk-io.h"
 24 #include "locking.h"
 25 #include "print-tree.h"
 26 #include "compat.h"
 27 #include "tree-log.h"
 28 
 29 /* magic values for the inode_only field in btrfs_log_inode:
 30  *
 31  * LOG_INODE_ALL means to log everything
 32  * LOG_INODE_EXISTS means to log just enough to recreate the inode
 33  * during log replay
 34  */
 35 #define LOG_INODE_ALL 0
 36 #define LOG_INODE_EXISTS 1
 37 
 38 /*
 39  * directory trouble cases
 40  *
 41  * 1) on rename or unlink, if the inode being unlinked isn't in the fsync
 42  * log, we must force a full commit before doing an fsync of the directory
 43  * where the unlink was done.
 44  * ---> record transid of last unlink/rename per directory
 45  *
 46  * mkdir foo/some_dir
 47  * normal commit
 48  * rename foo/some_dir foo2/some_dir
 49  * mkdir foo/some_dir
 50  * fsync foo/some_dir/some_file
 51  *
 52  * The fsync above will unlink the original some_dir without recording
 53  * it in its new location (foo2).  After a crash, some_dir will be gone
 54  * unless the fsync of some_file forces a full commit
 55  *
 56  * 2) we must log any new names for any file or dir that is in the fsync
 57  * log. ---> check inode while renaming/linking.
 58  *
 59  * 2a) we must log any new names for any file or dir during rename
 60  * when the directory they are being removed from was logged.
 61  * ---> check inode and old parent dir during rename
 62  *
 63  *  2a is actually the more important variant.  With the extra logging
 64  *  a crash might unlink the old name without recreating the new one
 65  *
 66  * 3) after a crash, we must go through any directories with a link count
 67  * of zero and redo the rm -rf
 68  *
 69  * mkdir f1/foo
 70  * normal commit
 71  * rm -rf f1/foo
 72  * fsync(f1)
 73  *
 74  * The directory f1 was fully removed from the FS, but fsync was never
 75  * called on f1, only its parent dir.  After a crash the rm -rf must
 76  * be replayed.  This must be able to recurse down the entire
 77  * directory tree.  The inode link count fixup code takes care of the
 78  * ugly details.
 79  */
 80 
 81 /*
 82  * stages for the tree walking.  The first
 83  * stage (0) is to only pin down the blocks we find
 84  * the second stage (1) is to make sure that all the inodes
 85  * we find in the log are created in the subvolume.
 86  *
 87  * The last stage is to deal with directories and links and extents
 88  * and all the other fun semantics
 89  */
 90 #define LOG_WALK_PIN_ONLY 0
 91 #define LOG_WALK_REPLAY_INODES 1
 92 #define LOG_WALK_REPLAY_ALL 2
 93 
 94 static int btrfs_log_inode(struct btrfs_trans_handle *trans,
 95                              struct btrfs_root *root, struct inode *inode,
 96                              int inode_only);
 97 static int link_to_fixup_dir(struct btrfs_trans_handle *trans,
 98                              struct btrfs_root *root,
 99                              struct btrfs_path *path, u64 objectid);
100 static noinline int replay_dir_deletes(struct btrfs_trans_handle *trans,
101                                        struct btrfs_root *root,
102                                        struct btrfs_root *log,
103                                        struct btrfs_path *path,
104                                        u64 dirid, int del_all);
105 
106 /*
107  * tree logging is a special write ahead log used to make sure that
108  * fsyncs and O_SYNCs can happen without doing full tree commits.
109  *
110  * Full tree commits are expensive because they require commonly
111  * modified blocks to be recowed, creating many dirty pages in the
112  * extent tree an 4x-6x higher write load than ext3.
113  *
114  * Instead of doing a tree commit on every fsync, we use the
115  * key ranges and transaction ids to find items for a given file or directory
116  * that have changed in this transaction.  Those items are copied into
117  * a special tree (one per subvolume root), that tree is written to disk
118  * and then the fsync is considered complete.
119  *
120  * After a crash, items are copied out of the log-tree back into the
121  * subvolume tree.  Any file data extents found are recorded in the extent
122  * allocation tree, and the log-tree freed.
123  *
124  * The log tree is read three times, once to pin down all the extents it is
125  * using in ram and once, once to create all the inodes logged in the tree
126  * and once to do all the other items.
127  */
128 
129 /*
130  * start a sub transaction and setup the log tree
131  * this increments the log tree writer count to make the people
132  * syncing the tree wait for us to finish
133  */
134 static int start_log_trans(struct btrfs_trans_handle *trans,
135                            struct btrfs_root *root)
136 {
137         int ret;
138         int err = 0;
139 
140         mutex_lock(&root->log_mutex);
141         if (root->log_root) {
142                 if (!root->log_start_pid) {
143                         root->log_start_pid = current->pid;
144                         root->log_multiple_pids = false;
145                 } else if (root->log_start_pid != current->pid) {
146                         root->log_multiple_pids = true;
147                 }
148 
149                 root->log_batch++;
150                 atomic_inc(&root->log_writers);
151                 mutex_unlock(&root->log_mutex);
152                 return 0;
153         }
154         root->log_multiple_pids = false;
155         root->log_start_pid = current->pid;
156         mutex_lock(&root->fs_info->tree_log_mutex);
157         if (!root->fs_info->log_root_tree) {
158                 ret = btrfs_init_log_root_tree(trans, root->fs_info);
159                 if (ret)
160                         err = ret;
161         }
162         if (err == 0 && !root->log_root) {
163                 ret = btrfs_add_log_tree(trans, root);
164                 if (ret)
165                         err = ret;
166         }
167         mutex_unlock(&root->fs_info->tree_log_mutex);
168         root->log_batch++;
169         atomic_inc(&root->log_writers);
170         mutex_unlock(&root->log_mutex);
171         return err;
172 }
173 
174 /*
175  * returns 0 if there was a log transaction running and we were able
176  * to join, or returns -ENOENT if there were not transactions
177  * in progress
178  */
179 static int join_running_log_trans(struct btrfs_root *root)
180 {
181         int ret = -ENOENT;
182 
183         smp_mb();
184         if (!root->log_root)
185                 return -ENOENT;
186 
187         mutex_lock(&root->log_mutex);
188         if (root->log_root) {
189                 ret = 0;
190                 atomic_inc(&root->log_writers);
191         }
192         mutex_unlock(&root->log_mutex);
193         return ret;
194 }
195 
196 /*
197  * This either makes the current running log transaction wait
198  * until you call btrfs_end_log_trans() or it makes any future
199  * log transactions wait until you call btrfs_end_log_trans()
200  */
201 int btrfs_pin_log_trans(struct btrfs_root *root)
202 {
203         int ret = -ENOENT;
204 
205         mutex_lock(&root->log_mutex);
206         atomic_inc(&root->log_writers);
207         mutex_unlock(&root->log_mutex);
208         return ret;
209 }
210 
211 /*
212  * indicate we're done making changes to the log tree
213  * and wake up anyone waiting to do a sync
214  */
215 void btrfs_end_log_trans(struct btrfs_root *root)
216 {
217         if (atomic_dec_and_test(&root->log_writers)) {
218                 smp_mb();
219                 if (waitqueue_active(&root->log_writer_wait))
220                         wake_up(&root->log_writer_wait);
221         }
222 }
223 
224 
225 /*
226  * the walk control struct is used to pass state down the chain when
227  * processing the log tree.  The stage field tells us which part
228  * of the log tree processing we are currently doing.  The others
229  * are state fields used for that specific part
230  */
231 struct walk_control {
232         /* should we free the extent on disk when done?  This is used
233          * at transaction commit time while freeing a log tree
234          */
235         int free;
236 
237         /* should we write out the extent buffer?  This is used
238          * while flushing the log tree to disk during a sync
239          */
240         int write;
241 
242         /* should we wait for the extent buffer io to finish?  Also used
243          * while flushing the log tree to disk for a sync
244          */
245         int wait;
246 
247         /* pin only walk, we record which extents on disk belong to the
248          * log trees
249          */
250         int pin;
251 
252         /* what stage of the replay code we're currently in */
253         int stage;
254 
255         /* the root we are currently replaying */
256         struct btrfs_root *replay_dest;
257 
258         /* the trans handle for the current replay */
259         struct btrfs_trans_handle *trans;
260 
261         /* the function that gets used to process blocks we find in the
262          * tree.  Note the extent_buffer might not be up to date when it is
263          * passed in, and it must be checked or read if you need the data
264          * inside it
265          */
266         int (*process_func)(struct btrfs_root *log, struct extent_buffer *eb,
267                             struct walk_control *wc, u64 gen);
268 };
269 
270 /*
271  * process_func used to pin down extents, write them or wait on them
272  */
273 static int process_one_buffer(struct btrfs_root *log,
274                               struct extent_buffer *eb,
275                               struct walk_control *wc, u64 gen)
276 {
277         if (wc->pin)
278                 btrfs_pin_extent_for_log_replay(wc->trans,
279                                                 log->fs_info->extent_root,
280                                                 eb->start, eb->len);
281 
282         if (btrfs_buffer_uptodate(eb, gen, 0)) {
283                 if (wc->write)
284                         btrfs_write_tree_block(eb);
285                 if (wc->wait)
286                         btrfs_wait_tree_block_writeback(eb);
287         }
288         return 0;
289 }
290 
291 /*
292  * Item overwrite used by replay and tree logging.  eb, slot and key all refer
293  * to the src data we are copying out.
294  *
295  * root is the tree we are copying into, and path is a scratch
296  * path for use in this function (it should be released on entry and
297  * will be released on exit).
298  *
299  * If the key is already in the destination tree the existing item is
300  * overwritten.  If the existing item isn't big enough, it is extended.
301  * If it is too large, it is truncated.
302  *
303  * If the key isn't in the destination yet, a new item is inserted.
304  */
305 static noinline int overwrite_item(struct btrfs_trans_handle *trans,
306                                    struct btrfs_root *root,
307                                    struct btrfs_path *path,
308                                    struct extent_buffer *eb, int slot,
309                                    struct btrfs_key *key)
310 {
311         int ret;
312         u32 item_size;
313         u64 saved_i_size = 0;
314         int save_old_i_size = 0;
315         unsigned long src_ptr;
316         unsigned long dst_ptr;
317         int overwrite_root = 0;
318 
319         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
320                 overwrite_root = 1;
321 
322         item_size = btrfs_item_size_nr(eb, slot);
323         src_ptr = btrfs_item_ptr_offset(eb, slot);
324 
325         /* look for the key in the destination tree */
326         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
327         if (ret == 0) {
328                 char *src_copy;
329                 char *dst_copy;
330                 u32 dst_size = btrfs_item_size_nr(path->nodes[0],
331                                                   path->slots[0]);
332                 if (dst_size != item_size)
333                         goto insert;
334 
335                 if (item_size == 0) {
336                         btrfs_release_path(path);
337                         return 0;
338                 }
339                 dst_copy = kmalloc(item_size, GFP_NOFS);
340                 src_copy = kmalloc(item_size, GFP_NOFS);
341                 if (!dst_copy || !src_copy) {
342                         btrfs_release_path(path);
343                         kfree(dst_copy);
344                         kfree(src_copy);
345                         return -ENOMEM;
346                 }
347 
348                 read_extent_buffer(eb, src_copy, src_ptr, item_size);
349 
350                 dst_ptr = btrfs_item_ptr_offset(path->nodes[0], path->slots[0]);
351                 read_extent_buffer(path->nodes[0], dst_copy, dst_ptr,
352                                    item_size);
353                 ret = memcmp(dst_copy, src_copy, item_size);
354 
355                 kfree(dst_copy);
356                 kfree(src_copy);
357                 /*
358                  * they have the same contents, just return, this saves
359                  * us from cowing blocks in the destination tree and doing
360                  * extra writes that may not have been done by a previous
361                  * sync
362                  */
363                 if (ret == 0) {
364                         btrfs_release_path(path);
365                         return 0;
366                 }
367 
368         }
369 insert:
370         btrfs_release_path(path);
371         /* try to insert the key into the destination tree */
372         ret = btrfs_insert_empty_item(trans, root, path,
373                                       key, item_size);
374 
375         /* make sure any existing item is the correct size */
376         if (ret == -EEXIST) {
377                 u32 found_size;
378                 found_size = btrfs_item_size_nr(path->nodes[0],
379                                                 path->slots[0]);
380                 if (found_size > item_size)
381                         btrfs_truncate_item(trans, root, path, item_size, 1);
382                 else if (found_size < item_size)
383                         btrfs_extend_item(trans, root, path,
384                                           item_size - found_size);
385         } else if (ret) {
386                 return ret;
387         }
388         dst_ptr = btrfs_item_ptr_offset(path->nodes[0],
389                                         path->slots[0]);
390 
391         /* don't overwrite an existing inode if the generation number
392          * was logged as zero.  This is done when the tree logging code
393          * is just logging an inode to make sure it exists after recovery.
394          *
395          * Also, don't overwrite i_size on directories during replay.
396          * log replay inserts and removes directory items based on the
397          * state of the tree found in the subvolume, and i_size is modified
398          * as it goes
399          */
400         if (key->type == BTRFS_INODE_ITEM_KEY && ret == -EEXIST) {
401                 struct btrfs_inode_item *src_item;
402                 struct btrfs_inode_item *dst_item;
403 
404                 src_item = (struct btrfs_inode_item *)src_ptr;
405                 dst_item = (struct btrfs_inode_item *)dst_ptr;
406 
407                 if (btrfs_inode_generation(eb, src_item) == 0)
408                         goto no_copy;
409 
410                 if (overwrite_root &&
411                     S_ISDIR(btrfs_inode_mode(eb, src_item)) &&
412                     S_ISDIR(btrfs_inode_mode(path->nodes[0], dst_item))) {
413                         save_old_i_size = 1;
414                         saved_i_size = btrfs_inode_size(path->nodes[0],
415                                                         dst_item);
416                 }
417         }
418 
419         copy_extent_buffer(path->nodes[0], eb, dst_ptr,
420                            src_ptr, item_size);
421 
422         if (save_old_i_size) {
423                 struct btrfs_inode_item *dst_item;
424                 dst_item = (struct btrfs_inode_item *)dst_ptr;
425                 btrfs_set_inode_size(path->nodes[0], dst_item, saved_i_size);
426         }
427 
428         /* make sure the generation is filled in */
429         if (key->type == BTRFS_INODE_ITEM_KEY) {
430                 struct btrfs_inode_item *dst_item;
431                 dst_item = (struct btrfs_inode_item *)dst_ptr;
432                 if (btrfs_inode_generation(path->nodes[0], dst_item) == 0) {
433                         btrfs_set_inode_generation(path->nodes[0], dst_item,
434                                                    trans->transid);
435                 }
436         }
437 no_copy:
438         btrfs_mark_buffer_dirty(path->nodes[0]);
439         btrfs_release_path(path);
440         return 0;
441 }
442 
443 /*
444  * simple helper to read an inode off the disk from a given root
445  * This can only be called for subvolume roots and not for the log
446  */
447 static noinline struct inode *read_one_inode(struct btrfs_root *root,
448                                              u64 objectid)
449 {
450         struct btrfs_key key;
451         struct inode *inode;
452 
453         key.objectid = objectid;
454         key.type = BTRFS_INODE_ITEM_KEY;
455         key.offset = 0;
456         inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
457         if (IS_ERR(inode)) {
458                 inode = NULL;
459         } else if (is_bad_inode(inode)) {
460                 iput(inode);
461                 inode = NULL;
462         }
463         return inode;
464 }
465 
466 /* replays a single extent in 'eb' at 'slot' with 'key' into the
467  * subvolume 'root'.  path is released on entry and should be released
468  * on exit.
469  *
470  * extents in the log tree have not been allocated out of the extent
471  * tree yet.  So, this completes the allocation, taking a reference
472  * as required if the extent already exists or creating a new extent
473  * if it isn't in the extent allocation tree yet.
474  *
475  * The extent is inserted into the file, dropping any existing extents
476  * from the file that overlap the new one.
477  */
478 static noinline int replay_one_extent(struct btrfs_trans_handle *trans,
479                                       struct btrfs_root *root,
480                                       struct btrfs_path *path,
481                                       struct extent_buffer *eb, int slot,
482                                       struct btrfs_key *key)
483 {
484         int found_type;
485         u64 mask = root->sectorsize - 1;
486         u64 extent_end;
487         u64 alloc_hint;
488         u64 start = key->offset;
489         u64 saved_nbytes;
490         struct btrfs_file_extent_item *item;
491         struct inode *inode = NULL;
492         unsigned long size;
493         int ret = 0;
494 
495         item = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
496         found_type = btrfs_file_extent_type(eb, item);
497 
498         if (found_type == BTRFS_FILE_EXTENT_REG ||
499             found_type == BTRFS_FILE_EXTENT_PREALLOC)
500                 extent_end = start + btrfs_file_extent_num_bytes(eb, item);
501         else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
502                 size = btrfs_file_extent_inline_len(eb, item);
503                 extent_end = (start + size + mask) & ~mask;
504         } else {
505                 ret = 0;
506                 goto out;
507         }
508 
509         inode = read_one_inode(root, key->objectid);
510         if (!inode) {
511                 ret = -EIO;
512                 goto out;
513         }
514 
515         /*
516          * first check to see if we already have this extent in the
517          * file.  This must be done before the btrfs_drop_extents run
518          * so we don't try to drop this extent.
519          */
520         ret = btrfs_lookup_file_extent(trans, root, path, btrfs_ino(inode),
521                                        start, 0);
522 
523         if (ret == 0 &&
524             (found_type == BTRFS_FILE_EXTENT_REG ||
525              found_type == BTRFS_FILE_EXTENT_PREALLOC)) {
526                 struct btrfs_file_extent_item cmp1;
527                 struct btrfs_file_extent_item cmp2;
528                 struct btrfs_file_extent_item *existing;
529                 struct extent_buffer *leaf;
530 
531                 leaf = path->nodes[0];
532                 existing = btrfs_item_ptr(leaf, path->slots[0],
533                                           struct btrfs_file_extent_item);
534 
535                 read_extent_buffer(eb, &cmp1, (unsigned long)item,
536                                    sizeof(cmp1));
537                 read_extent_buffer(leaf, &cmp2, (unsigned long)existing,
538                                    sizeof(cmp2));
539 
540                 /*
541                  * we already have a pointer to this exact extent,
542                  * we don't have to do anything
543                  */
544                 if (memcmp(&cmp1, &cmp2, sizeof(cmp1)) == 0) {
545                         btrfs_release_path(path);
546                         goto out;
547                 }
548         }
549         btrfs_release_path(path);
550 
551         saved_nbytes = inode_get_bytes(inode);
552         /* drop any overlapping extents */
553         ret = btrfs_drop_extents(trans, inode, start, extent_end,
554                                  &alloc_hint, 1);
555         BUG_ON(ret);
556 
557         if (found_type == BTRFS_FILE_EXTENT_REG ||
558             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
559                 u64 offset;
560                 unsigned long dest_offset;
561                 struct btrfs_key ins;
562 
563                 ret = btrfs_insert_empty_item(trans, root, path, key,
564                                               sizeof(*item));
565                 BUG_ON(ret);
566                 dest_offset = btrfs_item_ptr_offset(path->nodes[0],
567                                                     path->slots[0]);
568                 copy_extent_buffer(path->nodes[0], eb, dest_offset,
569                                 (unsigned long)item,  sizeof(*item));
570 
571                 ins.objectid = btrfs_file_extent_disk_bytenr(eb, item);
572                 ins.offset = btrfs_file_extent_disk_num_bytes(eb, item);
573                 ins.type = BTRFS_EXTENT_ITEM_KEY;
574                 offset = key->offset - btrfs_file_extent_offset(eb, item);
575 
576                 if (ins.objectid > 0) {
577                         u64 csum_start;
578                         u64 csum_end;
579                         LIST_HEAD(ordered_sums);
580                         /*
581                          * is this extent already allocated in the extent
582                          * allocation tree?  If so, just add a reference
583                          */
584                         ret = btrfs_lookup_extent(root, ins.objectid,
585                                                 ins.offset);
586                         if (ret == 0) {
587                                 ret = btrfs_inc_extent_ref(trans, root,
588                                                 ins.objectid, ins.offset,
589                                                 0, root->root_key.objectid,
590                                                 key->objectid, offset, 0);
591                                 BUG_ON(ret);
592                         } else {
593                                 /*
594                                  * insert the extent pointer in the extent
595                                  * allocation tree
596                                  */
597                                 ret = btrfs_alloc_logged_file_extent(trans,
598                                                 root, root->root_key.objectid,
599                                                 key->objectid, offset, &ins);
600                                 BUG_ON(ret);
601                         }
602                         btrfs_release_path(path);
603 
604                         if (btrfs_file_extent_compression(eb, item)) {
605                                 csum_start = ins.objectid;
606                                 csum_end = csum_start + ins.offset;
607                         } else {
608                                 csum_start = ins.objectid +
609                                         btrfs_file_extent_offset(eb, item);
610                                 csum_end = csum_start +
611                                         btrfs_file_extent_num_bytes(eb, item);
612                         }
613 
614                         ret = btrfs_lookup_csums_range(root->log_root,
615                                                 csum_start, csum_end - 1,
616                                                 &ordered_sums, 0);
617                         BUG_ON(ret);
618                         while (!list_empty(&ordered_sums)) {
619                                 struct btrfs_ordered_sum *sums;
620                                 sums = list_entry(ordered_sums.next,
621                                                 struct btrfs_ordered_sum,
622                                                 list);
623                                 ret = btrfs_csum_file_blocks(trans,
624                                                 root->fs_info->csum_root,
625                                                 sums);
626                                 BUG_ON(ret);
627                                 list_del(&sums->list);
628                                 kfree(sums);
629                         }
630                 } else {
631                         btrfs_release_path(path);
632                 }
633         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
634                 /* inline extents are easy, we just overwrite them */
635                 ret = overwrite_item(trans, root, path, eb, slot, key);
636                 BUG_ON(ret);
637         }
638 
639         inode_set_bytes(inode, saved_nbytes);
640         btrfs_update_inode(trans, root, inode);
641 out:
642         if (inode)
643                 iput(inode);
644         return ret;
645 }
646 
647 /*
648  * when cleaning up conflicts between the directory names in the
649  * subvolume, directory names in the log and directory names in the
650  * inode back references, we may have to unlink inodes from directories.
651  *
652  * This is a helper function to do the unlink of a specific directory
653  * item
654  */
655 static noinline int drop_one_dir_item(struct btrfs_trans_handle *trans,
656                                       struct btrfs_root *root,
657                                       struct btrfs_path *path,
658                                       struct inode *dir,
659                                       struct btrfs_dir_item *di)
660 {
661         struct inode *inode;
662         char *name;
663         int name_len;
664         struct extent_buffer *leaf;
665         struct btrfs_key location;
666         int ret;
667 
668         leaf = path->nodes[0];
669 
670         btrfs_dir_item_key_to_cpu(leaf, di, &location);
671         name_len = btrfs_dir_name_len(leaf, di);
672         name = kmalloc(name_len, GFP_NOFS);
673         if (!name)
674                 return -ENOMEM;
675 
676         read_extent_buffer(leaf, name, (unsigned long)(di + 1), name_len);
677         btrfs_release_path(path);
678 
679         inode = read_one_inode(root, location.objectid);
680         if (!inode) {
681                 kfree(name);
682                 return -EIO;
683         }
684 
685         ret = link_to_fixup_dir(trans, root, path, location.objectid);
686         BUG_ON(ret);
687 
688         ret = btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
689         BUG_ON(ret);
690         kfree(name);
691 
692         iput(inode);
693 
694         btrfs_run_delayed_items(trans, root);
695         return ret;
696 }
697 
698 /*
699  * helper function to see if a given name and sequence number found
700  * in an inode back reference are already in a directory and correctly
701  * point to this inode
702  */
703 static noinline int inode_in_dir(struct btrfs_root *root,
704                                  struct btrfs_path *path,
705                                  u64 dirid, u64 objectid, u64 index,
706                                  const char *name, int name_len)
707 {
708         struct btrfs_dir_item *di;
709         struct btrfs_key location;
710         int match = 0;
711 
712         di = btrfs_lookup_dir_index_item(NULL, root, path, dirid,
713                                          index, name, name_len, 0);
714         if (di && !IS_ERR(di)) {
715                 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
716                 if (location.objectid != objectid)
717                         goto out;
718         } else
719                 goto out;
720         btrfs_release_path(path);
721 
722         di = btrfs_lookup_dir_item(NULL, root, path, dirid, name, name_len, 0);
723         if (di && !IS_ERR(di)) {
724                 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
725                 if (location.objectid != objectid)
726                         goto out;
727         } else
728                 goto out;
729         match = 1;
730 out:
731         btrfs_release_path(path);
732         return match;
733 }
734 
735 /*
736  * helper function to check a log tree for a named back reference in
737  * an inode.  This is used to decide if a back reference that is
738  * found in the subvolume conflicts with what we find in the log.
739  *
740  * inode backreferences may have multiple refs in a single item,
741  * during replay we process one reference at a time, and we don't
742  * want to delete valid links to a file from the subvolume if that
743  * link is also in the log.
744  */
745 static noinline int backref_in_log(struct btrfs_root *log,
746                                    struct btrfs_key *key,
747                                    char *name, int namelen)
748 {
749         struct btrfs_path *path;
750         struct btrfs_inode_ref *ref;
751         unsigned long ptr;
752         unsigned long ptr_end;
753         unsigned long name_ptr;
754         int found_name_len;
755         int item_size;
756         int ret;
757         int match = 0;
758 
759         path = btrfs_alloc_path();
760         if (!path)
761                 return -ENOMEM;
762 
763         ret = btrfs_search_slot(NULL, log, key, path, 0, 0);
764         if (ret != 0)
765                 goto out;
766 
767         item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
768         ptr = btrfs_item_ptr_offset(path->nodes[0], path->slots[0]);
769         ptr_end = ptr + item_size;
770         while (ptr < ptr_end) {
771                 ref = (struct btrfs_inode_ref *)ptr;
772                 found_name_len = btrfs_inode_ref_name_len(path->nodes[0], ref);
773                 if (found_name_len == namelen) {
774                         name_ptr = (unsigned long)(ref + 1);
775                         ret = memcmp_extent_buffer(path->nodes[0], name,
776                                                    name_ptr, namelen);
777                         if (ret == 0) {
778                                 match = 1;
779                                 goto out;
780                         }
781                 }
782                 ptr = (unsigned long)(ref + 1) + found_name_len;
783         }
784 out:
785         btrfs_free_path(path);
786         return match;
787 }
788 
789 
790 /*
791  * replay one inode back reference item found in the log tree.
792  * eb, slot and key refer to the buffer and key found in the log tree.
793  * root is the destination we are replaying into, and path is for temp
794  * use by this function.  (it should be released on return).
795  */
796 static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
797                                   struct btrfs_root *root,
798                                   struct btrfs_root *log,
799                                   struct btrfs_path *path,
800                                   struct extent_buffer *eb, int slot,
801                                   struct btrfs_key *key)
802 {
803         struct btrfs_inode_ref *ref;
804         struct btrfs_dir_item *di;
805         struct inode *dir;
806         struct inode *inode;
807         unsigned long ref_ptr;
808         unsigned long ref_end;
809         char *name;
810         int namelen;
811         int ret;
812         int search_done = 0;
813 
814         /*
815          * it is possible that we didn't log all the parent directories
816          * for a given inode.  If we don't find the dir, just don't
817          * copy the back ref in.  The link count fixup code will take
818          * care of the rest
819          */
820         dir = read_one_inode(root, key->offset);
821         if (!dir)
822                 return -ENOENT;
823 
824         inode = read_one_inode(root, key->objectid);
825         if (!inode) {
826                 iput(dir);
827                 return -EIO;
828         }
829 
830         ref_ptr = btrfs_item_ptr_offset(eb, slot);
831         ref_end = ref_ptr + btrfs_item_size_nr(eb, slot);
832 
833 again:
834         ref = (struct btrfs_inode_ref *)ref_ptr;
835 
836         namelen = btrfs_inode_ref_name_len(eb, ref);
837         name = kmalloc(namelen, GFP_NOFS);
838         BUG_ON(!name);
839 
840         read_extent_buffer(eb, name, (unsigned long)(ref + 1), namelen);
841 
842         /* if we already have a perfect match, we're done */
843         if (inode_in_dir(root, path, btrfs_ino(dir), btrfs_ino(inode),
844                          btrfs_inode_ref_index(eb, ref),
845                          name, namelen)) {
846                 goto out;
847         }
848 
849         /*
850          * look for a conflicting back reference in the metadata.
851          * if we find one we have to unlink that name of the file
852          * before we add our new link.  Later on, we overwrite any
853          * existing back reference, and we don't want to create
854          * dangling pointers in the directory.
855          */
856 
857         if (search_done)
858                 goto insert;
859 
860         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
861         if (ret == 0) {
862                 char *victim_name;
863                 int victim_name_len;
864                 struct btrfs_inode_ref *victim_ref;
865                 unsigned long ptr;
866                 unsigned long ptr_end;
867                 struct extent_buffer *leaf = path->nodes[0];
868 
869                 /* are we trying to overwrite a back ref for the root directory
870                  * if so, just jump out, we're done
871                  */
872                 if (key->objectid == key->offset)
873                         goto out_nowrite;
874 
875                 /* check all the names in this back reference to see
876                  * if they are in the log.  if so, we allow them to stay
877                  * otherwise they must be unlinked as a conflict
878                  */
879                 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
880                 ptr_end = ptr + btrfs_item_size_nr(leaf, path->slots[0]);
881                 while (ptr < ptr_end) {
882                         victim_ref = (struct btrfs_inode_ref *)ptr;
883                         victim_name_len = btrfs_inode_ref_name_len(leaf,
884                                                                    victim_ref);
885                         victim_name = kmalloc(victim_name_len, GFP_NOFS);
886                         BUG_ON(!victim_name);
887 
888                         read_extent_buffer(leaf, victim_name,
889                                            (unsigned long)(victim_ref + 1),
890                                            victim_name_len);
891 
892                         if (!backref_in_log(log, key, victim_name,
893                                             victim_name_len)) {
894                                 btrfs_inc_nlink(inode);
895                                 btrfs_release_path(path);
896 
897                                 ret = btrfs_unlink_inode(trans, root, dir,
898                                                          inode, victim_name,
899                                                          victim_name_len);
900                                 btrfs_run_delayed_items(trans, root);
901                         }
902                         kfree(victim_name);
903                         ptr = (unsigned long)(victim_ref + 1) + victim_name_len;
904                 }
905                 BUG_ON(ret);
906 
907                 /*
908                  * NOTE: we have searched root tree and checked the
909                  * coresponding ref, it does not need to check again.
910                  */
911                 search_done = 1;
912         }
913         btrfs_release_path(path);
914 
915         /* look for a conflicting sequence number */
916         di = btrfs_lookup_dir_index_item(trans, root, path, btrfs_ino(dir),
917                                          btrfs_inode_ref_index(eb, ref),
918                                          name, namelen, 0);
919         if (di && !IS_ERR(di)) {
920                 ret = drop_one_dir_item(trans, root, path, dir, di);
921                 BUG_ON(ret);
922         }
923         btrfs_release_path(path);
924 
925         /* look for a conflicing name */
926         di = btrfs_lookup_dir_item(trans, root, path, btrfs_ino(dir),
927                                    name, namelen, 0);
928         if (di && !IS_ERR(di)) {
929                 ret = drop_one_dir_item(trans, root, path, dir, di);
930                 BUG_ON(ret);
931         }
932         btrfs_release_path(path);
933 
934 insert:
935         /* insert our name */
936         ret = btrfs_add_link(trans, dir, inode, name, namelen, 0,
937                              btrfs_inode_ref_index(eb, ref));
938         BUG_ON(ret);
939 
940         btrfs_update_inode(trans, root, inode);
941 
942 out:
943         ref_ptr = (unsigned long)(ref + 1) + namelen;
944         kfree(name);
945         if (ref_ptr < ref_end)
946                 goto again;
947 
948         /* finally write the back reference in the inode */
949         ret = overwrite_item(trans, root, path, eb, slot, key);
950         BUG_ON(ret);
951 
952 out_nowrite:
953         btrfs_release_path(path);
954         iput(dir);
955         iput(inode);
956         return 0;
957 }
958 
959 static int insert_orphan_item(struct btrfs_trans_handle *trans,
960                               struct btrfs_root *root, u64 offset)
961 {
962         int ret;
963         ret = btrfs_find_orphan_item(root, offset);
964         if (ret > 0)
965                 ret = btrfs_insert_orphan_item(trans, root, offset);
966         return ret;
967 }
968 
969 
970 /*
971  * There are a few corners where the link count of the file can't
972  * be properly maintained during replay.  So, instead of adding
973  * lots of complexity to the log code, we just scan the backrefs
974  * for any file that has been through replay.
975  *
976  * The scan will update the link count on the inode to reflect the
977  * number of back refs found.  If it goes down to zero, the iput
978  * will free the inode.
979  */
980 static noinline int fixup_inode_link_count(struct btrfs_trans_handle *trans,
981                                            struct btrfs_root *root,
982                                            struct inode *inode)
983 {
984         struct btrfs_path *path;
985         int ret;
986         struct btrfs_key key;
987         u64 nlink = 0;
988         unsigned long ptr;
989         unsigned long ptr_end;
990         int name_len;
991         u64 ino = btrfs_ino(inode);
992 
993         key.objectid = ino;
994         key.type = BTRFS_INODE_REF_KEY;
995         key.offset = (u64)-1;
996 
997         path = btrfs_alloc_path();
998         if (!path)
999                 return -ENOMEM;
1000 
1001         while (1) {
1002                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1003                 if (ret < 0)
1004                         break;
1005                 if (ret > 0) {
1006                         if (path->slots[0] == 0)
1007                                 break;
1008                         path->slots[0]--;
1009                 }
1010                 btrfs_item_key_to_cpu(path->nodes[0], &key,
1011                                       path->slots[0]);
1012                 if (key.objectid != ino ||
1013                     key.type != BTRFS_INODE_REF_KEY)
1014                         break;
1015                 ptr = btrfs_item_ptr_offset(path->nodes[0], path->slots[0]);
1016                 ptr_end = ptr + btrfs_item_size_nr(path->nodes[0],
1017                                                    path->slots[0]);
1018                 while (ptr < ptr_end) {
1019                         struct btrfs_inode_ref *ref;
1020 
1021                         ref = (struct btrfs_inode_ref *)ptr;
1022                         name_len = btrfs_inode_ref_name_len(path->nodes[0],
1023                                                             ref);
1024                         ptr = (unsigned long)(ref + 1) + name_len;
1025                         nlink++;
1026                 }
1027 
1028                 if (key.offset == 0)
1029                         break;
1030                 key.offset--;
1031                 btrfs_release_path(path);
1032         }
1033         btrfs_release_path(path);
1034         if (nlink != inode->i_nlink) {
1035                 set_nlink(inode, nlink);
1036                 btrfs_update_inode(trans, root, inode);
1037         }
1038         BTRFS_I(inode)->index_cnt = (u64)-1;
1039 
1040         if (inode->i_nlink == 0) {
1041                 if (S_ISDIR(inode->i_mode)) {
1042                         ret = replay_dir_deletes(trans, root, NULL, path,
1043                                                  ino, 1);
1044                         BUG_ON(ret);
1045                 }
1046                 ret = insert_orphan_item(trans, root, ino);
1047                 BUG_ON(ret);
1048         }
1049         btrfs_free_path(path);
1050 
1051         return 0;
1052 }
1053 
1054 static noinline int fixup_inode_link_counts(struct btrfs_trans_handle *trans,
1055                                             struct btrfs_root *root,
1056                                             struct btrfs_path *path)
1057 {
1058         int ret;
1059         struct btrfs_key key;
1060         struct inode *inode;
1061 
1062         key.objectid = BTRFS_TREE_LOG_FIXUP_OBJECTID;
1063         key.type = BTRFS_ORPHAN_ITEM_KEY;
1064         key.offset = (u64)-1;
1065         while (1) {
1066                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1067                 if (ret < 0)
1068                         break;
1069 
1070                 if (ret == 1) {
1071                         if (path->slots[0] == 0)
1072                                 break;
1073                         path->slots[0]--;
1074                 }
1075 
1076                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1077                 if (key.objectid != BTRFS_TREE_LOG_FIXUP_OBJECTID ||
1078                     key.type != BTRFS_ORPHAN_ITEM_KEY)
1079                         break;
1080 
1081                 ret = btrfs_del_item(trans, root, path);
1082                 if (ret)
1083                         goto out;
1084 
1085                 btrfs_release_path(path);
1086                 inode = read_one_inode(root, key.offset);
1087                 if (!inode)
1088                         return -EIO;
1089 
1090                 ret = fixup_inode_link_count(trans, root, inode);
1091                 BUG_ON(ret);
1092 
1093                 iput(inode);
1094 
1095                 /*
1096                  * fixup on a directory may create new entries,
1097                  * make sure we always look for the highset possible
1098                  * offset
1099                  */
1100                 key.offset = (u64)-1;
1101         }
1102         ret = 0;
1103 out:
1104         btrfs_release_path(path);
1105         return ret;
1106 }
1107 
1108 
1109 /*
1110  * record a given inode in the fixup dir so we can check its link
1111  * count when replay is done.  The link count is incremented here
1112  * so the inode won't go away until we check it
1113  */
1114 static noinline int link_to_fixup_dir(struct btrfs_trans_handle *trans,
1115                                       struct btrfs_root *root,
1116                                       struct btrfs_path *path,
1117                                       u64 objectid)
1118 {
1119         struct btrfs_key key;
1120         int ret = 0;
1121         struct inode *inode;
1122 
1123         inode = read_one_inode(root, objectid);
1124         if (!inode)
1125                 return -EIO;
1126 
1127         key.objectid = BTRFS_TREE_LOG_FIXUP_OBJECTID;
1128         btrfs_set_key_type(&key, BTRFS_ORPHAN_ITEM_KEY);
1129         key.offset = objectid;
1130 
1131         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1132 
1133         btrfs_release_path(path);
1134         if (ret == 0) {
1135                 btrfs_inc_nlink(inode);
1136                 btrfs_update_inode(trans, root, inode);
1137         } else if (ret == -EEXIST) {
1138                 ret = 0;
1139         } else {
1140                 BUG();
1141         }
1142         iput(inode);
1143 
1144         return ret;
1145 }
1146 
1147 /*
1148  * when replaying the log for a directory, we only insert names
1149  * for inodes that actually exist.  This means an fsync on a directory
1150  * does not implicitly fsync all the new files in it
1151  */
1152 static noinline int insert_one_name(struct btrfs_trans_handle *trans,
1153                                     struct btrfs_root *root,
1154                                     struct btrfs_path *path,
1155                                     u64 dirid, u64 index,
1156                                     char *name, int name_len, u8 type,
1157                                     struct btrfs_key *location)
1158 {
1159         struct inode *inode;
1160         struct inode *dir;
1161         int ret;
1162 
1163         inode = read_one_inode(root, location->objectid);
1164         if (!inode)
1165                 return -ENOENT;
1166 
1167         dir = read_one_inode(root, dirid);
1168         if (!dir) {
1169                 iput(inode);
1170                 return -EIO;
1171         }
1172         ret = btrfs_add_link(trans, dir, inode, name, name_len, 1, index);
1173 
1174         /* FIXME, put inode into FIXUP list */
1175 
1176         iput(inode);
1177         iput(dir);
1178         return ret;
1179 }
1180 
1181 /*
1182  * take a single entry in a log directory item and replay it into
1183  * the subvolume.
1184  *
1185  * if a conflicting item exists in the subdirectory already,
1186  * the inode it points to is unlinked and put into the link count
1187  * fix up tree.
1188  *
1189  * If a name from the log points to a file or directory that does
1190  * not exist in the FS, it is skipped.  fsyncs on directories
1191  * do not force down inodes inside that directory, just changes to the
1192  * names or unlinks in a directory.
1193  */
1194 static noinline int replay_one_name(struct btrfs_trans_handle *trans,
1195                                     struct btrfs_root *root,
1196                                     struct btrfs_path *path,
1197                                     struct extent_buffer *eb,
1198                                     struct btrfs_dir_item *di,
1199                                     struct btrfs_key *key)
1200 {
1201         char *name;
1202         int name_len;
1203         struct btrfs_dir_item *dst_di;
1204         struct btrfs_key found_key;
1205         struct btrfs_key log_key;
1206         struct inode *dir;
1207         u8 log_type;
1208         int exists;
1209         int ret;
1210 
1211         dir = read_one_inode(root, key->objectid);
1212         if (!dir)
1213                 return -EIO;
1214 
1215         name_len = btrfs_dir_name_len(eb, di);
1216         name = kmalloc(name_len, GFP_NOFS);
1217         if (!name)
1218                 return -ENOMEM;
1219 
1220         log_type = btrfs_dir_type(eb, di);
1221         read_extent_buffer(eb, name, (unsigned long)(di + 1),
1222                    name_len);
1223 
1224         btrfs_dir_item_key_to_cpu(eb, di, &log_key);
1225         exists = btrfs_lookup_inode(trans, root, path, &log_key, 0);
1226         if (exists == 0)
1227                 exists = 1;
1228         else
1229                 exists = 0;
1230         btrfs_release_path(path);
1231 
1232         if (key->type == BTRFS_DIR_ITEM_KEY) {
1233                 dst_di = btrfs_lookup_dir_item(trans, root, path, key->objectid,
1234                                        name, name_len, 1);
1235         } else if (key->type == BTRFS_DIR_INDEX_KEY) {
1236                 dst_di = btrfs_lookup_dir_index_item(trans, root, path,
1237                                                      key->objectid,
1238                                                      key->offset, name,
1239                                                      name_len, 1);
1240         } else {
1241                 BUG();
1242         }
1243         if (IS_ERR_OR_NULL(dst_di)) {
1244                 /* we need a sequence number to insert, so we only
1245                  * do inserts for the BTRFS_DIR_INDEX_KEY types
1246                  */
1247                 if (key->type != BTRFS_DIR_INDEX_KEY)
1248                         goto out;
1249                 goto insert;
1250         }
1251 
1252         btrfs_dir_item_key_to_cpu(path->nodes[0], dst_di, &found_key);
1253         /* the existing item matches the logged item */
1254         if (found_key.objectid == log_key.objectid &&
1255             found_key.type == log_key.type &&
1256             found_key.offset == log_key.offset &&
1257             btrfs_dir_type(path->nodes[0], dst_di) == log_type) {
1258                 goto out;
1259         }
1260 
1261         /*
1262          * don't drop the conflicting directory entry if the inode
1263          * for the new entry doesn't exist
1264          */
1265         if (!exists)
1266                 goto out;
1267 
1268         ret = drop_one_dir_item(trans, root, path, dir, dst_di);
1269         BUG_ON(ret);
1270 
1271         if (key->type == BTRFS_DIR_INDEX_KEY)
1272                 goto insert;
1273 out:
1274         btrfs_release_path(path);
1275         kfree(name);
1276         iput(dir);
1277         return 0;
1278 
1279 insert:
1280         btrfs_release_path(path);
1281         ret = insert_one_name(trans, root, path, key->objectid, key->offset,
1282                               name, name_len, log_type, &log_key);
1283 
1284         BUG_ON(ret && ret != -ENOENT);
1285         goto out;
1286 }
1287 
1288 /*
1289  * find all the names in a directory item and reconcile them into
1290  * the subvolume.  Only BTRFS_DIR_ITEM_KEY types will have more than
1291  * one name in a directory item, but the same code gets used for
1292  * both directory index types
1293  */
1294 static noinline int replay_one_dir_item(struct btrfs_trans_handle *trans,
1295                                         struct btrfs_root *root,
1296                                         struct btrfs_path *path,
1297                                         struct extent_buffer *eb, int slot,
1298                                         struct btrfs_key *key)
1299 {
1300         int ret;
1301         u32 item_size = btrfs_item_size_nr(eb, slot);
1302         struct btrfs_dir_item *di;
1303         int name_len;
1304         unsigned long ptr;
1305         unsigned long ptr_end;
1306 
1307         ptr = btrfs_item_ptr_offset(eb, slot);
1308         ptr_end = ptr + item_size;
1309         while (ptr < ptr_end) {
1310                 di = (struct btrfs_dir_item *)ptr;
1311                 if (verify_dir_item(root, eb, di))
1312                         return -EIO;
1313                 name_len = btrfs_dir_name_len(eb, di);
1314                 ret = replay_one_name(trans, root, path, eb, di, key);
1315                 BUG_ON(ret);
1316                 ptr = (unsigned long)(di + 1);
1317                 ptr += name_len;
1318         }
1319         return 0;
1320 }
1321 
1322 /*
1323  * directory replay has two parts.  There are the standard directory
1324  * items in the log copied from the subvolume, and range items
1325  * created in the log while the subvolume was logged.
1326  *
1327  * The range items tell us which parts of the key space the log
1328  * is authoritative for.  During replay, if a key in the subvolume
1329  * directory is in a logged range item, but not actually in the log
1330  * that means it was deleted from the directory before the fsync
1331  * and should be removed.
1332  */
1333 static noinline int find_dir_range(struct btrfs_root *root,
1334                                    struct btrfs_path *path,
1335                                    u64 dirid, int key_type,
1336                                    u64 *start_ret, u64 *end_ret)
1337 {
1338         struct btrfs_key key;
1339         u64 found_end;
1340         struct btrfs_dir_log_item *item;
1341         int ret;
1342         int nritems;
1343 
1344         if (*start_ret == (u64)-1)
1345                 return 1;
1346 
1347         key.objectid = dirid;
1348         key.type = key_type;
1349         key.offset = *start_ret;
1350 
1351         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1352         if (ret < 0)
1353                 goto out;
1354         if (ret > 0) {
1355                 if (path->slots[0] == 0)
1356                         goto out;
1357                 path->slots[0]--;
1358         }
1359         if (ret != 0)
1360                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1361 
1362         if (key.type != key_type || key.objectid != dirid) {
1363                 ret = 1;
1364                 goto next;
1365         }
1366         item = btrfs_item_ptr(path->nodes[0], path->slots[0],
1367                               struct btrfs_dir_log_item);
1368         found_end = btrfs_dir_log_end(path->nodes[0], item);
1369 
1370         if (*start_ret >= key.offset && *start_ret <= found_end) {
1371                 ret = 0;
1372                 *start_ret = key.offset;
1373                 *end_ret = found_end;
1374                 goto out;
1375         }
1376         ret = 1;
1377 next:
1378         /* check the next slot in the tree to see if it is a valid item */
1379         nritems = btrfs_header_nritems(path->nodes[0]);
1380         if (path->slots[0] >= nritems) {
1381                 ret = btrfs_next_leaf(root, path);
1382                 if (ret)
1383                         goto out;
1384         } else {
1385                 path->slots[0]++;
1386         }
1387 
1388         btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1389 
1390         if (key.type != key_type || key.objectid != dirid) {
1391                 ret = 1;
1392                 goto out;
1393         }
1394         item = btrfs_item_ptr(path->nodes[0], path->slots[0],
1395                               struct btrfs_dir_log_item);
1396         found_end = btrfs_dir_log_end(path->nodes[0], item);
1397         *start_ret = key.offset;
1398         *end_ret = found_end;
1399         ret = 0;
1400 out:
1401         btrfs_release_path(path);
1402         return ret;
1403 }
1404 
1405 /*
1406  * this looks for a given directory item in the log.  If the directory
1407  * item is not in the log, the item is removed and the inode it points
1408  * to is unlinked
1409  */
1410 static noinline int check_item_in_log(struct btrfs_trans_handle *trans,
1411                                       struct btrfs_root *root,
1412                                       struct btrfs_root *log,
1413                                       struct btrfs_path *path,
1414                                       struct btrfs_path *log_path,
1415                                       struct inode *dir,
1416                                       struct btrfs_key *dir_key)
1417 {
1418         int ret;
1419         struct extent_buffer *eb;
1420         int slot;
1421         u32 item_size;
1422         struct btrfs_dir_item *di;
1423         struct btrfs_dir_item *log_di;
1424         int name_len;
1425         unsigned long ptr;
1426         unsigned long ptr_end;
1427         char *name;
1428         struct inode *inode;
1429         struct btrfs_key location;
1430 
1431 again:
1432         eb = path->nodes[0];
1433         slot = path->slots[0];
1434         item_size = btrfs_item_size_nr(eb, slot);
1435         ptr = btrfs_item_ptr_offset(eb, slot);
1436         ptr_end = ptr + item_size;
1437         while (ptr < ptr_end) {
1438                 di = (struct btrfs_dir_item *)ptr;
1439                 if (verify_dir_item(root, eb, di)) {
1440                         ret = -EIO;
1441                         goto out;
1442                 }
1443 
1444                 name_len = btrfs_dir_name_len(eb, di);
1445                 name = kmalloc(name_len, GFP_NOFS);
1446                 if (!name) {
1447                         ret = -ENOMEM;
1448                         goto out;
1449                 }
1450                 read_extent_buffer(eb, name, (unsigned long)(di + 1),
1451                                   name_len);
1452                 log_di = NULL;
1453                 if (log && dir_key->type == BTRFS_DIR_ITEM_KEY) {
1454                         log_di = btrfs_lookup_dir_item(trans, log, log_path,
1455                                                        dir_key->objectid,
1456                                                        name, name_len, 0);
1457                 } else if (log && dir_key->type == BTRFS_DIR_INDEX_KEY) {
1458                         log_di = btrfs_lookup_dir_index_item(trans, log,
1459                                                      log_path,
1460                                                      dir_key->objectid,
1461                                                      dir_key->offset,
1462                                                      name, name_len, 0);
1463                 }
1464                 if (IS_ERR_OR_NULL(log_di)) {
1465                         btrfs_dir_item_key_to_cpu(eb, di, &location);
1466                         btrfs_release_path(path);
1467                         btrfs_release_path(log_path);
1468                         inode = read_one_inode(root, location.objectid);
1469                         if (!inode) {
1470                                 kfree(name);
1471                                 return -EIO;
1472                         }
1473 
1474                         ret = link_to_fixup_dir(trans, root,
1475                                                 path, location.objectid);
1476                         BUG_ON(ret);
1477                         btrfs_inc_nlink(inode);
1478                         ret = btrfs_unlink_inode(trans, root, dir, inode,
1479                                                  name, name_len);
1480                         BUG_ON(ret);
1481 
1482                         btrfs_run_delayed_items(trans, root);
1483 
1484                         kfree(name);
1485                         iput(inode);
1486 
1487                         /* there might still be more names under this key
1488                          * check and repeat if required
1489                          */
1490                         ret = btrfs_search_slot(NULL, root, dir_key, path,
1491                                                 0, 0);
1492                         if (ret == 0)
1493                                 goto again;
1494                         ret = 0;
1495                         goto out;
1496                 }
1497                 btrfs_release_path(log_path);
1498                 kfree(name);
1499 
1500                 ptr = (unsigned long)(di + 1);
1501                 ptr += name_len;
1502         }
1503         ret = 0;
1504 out:
1505         btrfs_release_path(path);
1506         btrfs_release_path(log_path);
1507         return ret;
1508 }
1509 
1510 /*
1511  * deletion replay happens before we copy any new directory items
1512  * out of the log or out of backreferences from inodes.  It
1513  * scans the log to find ranges of keys that log is authoritative for,
1514  * and then scans the directory to find items in those ranges that are
1515  * not present in the log.
1516  *
1517  * Anything we don't find in the log is unlinked and removed from the
1518  * directory.
1519  */
1520 static noinline int replay_dir_deletes(struct btrfs_trans_handle *trans,
1521                                        struct btrfs_root *root,
1522                                        struct btrfs_root *log,
1523                                        struct btrfs_path *path,
1524                                        u64 dirid, int del_all)
1525 {
1526         u64 range_start;
1527         u64 range_end;
1528         int key_type = BTRFS_DIR_LOG_ITEM_KEY;
1529         int ret = 0;
1530         struct btrfs_key dir_key;
1531         struct btrfs_key found_key;
1532         struct btrfs_path *log_path;
1533         struct inode *dir;
1534 
1535         dir_key.objectid = dirid;
1536         dir_key.type = BTRFS_DIR_ITEM_KEY;
1537         log_path = btrfs_alloc_path();
1538         if (!log_path)
1539                 return -ENOMEM;
1540 
1541         dir = read_one_inode(root, dirid);
1542         /* it isn't an error if the inode isn't there, that can happen
1543          * because we replay the deletes before we copy in the inode item
1544          * from the log
1545          */
1546         if (!dir) {
1547                 btrfs_free_path(log_path);
1548                 return 0;
1549         }
1550 again:
1551         range_start = 0;
1552         range_end = 0;
1553         while (1) {
1554                 if (del_all)
1555                         range_end = (u64)-1;
1556                 else {
1557                         ret = find_dir_range(log, path, dirid, key_type,
1558                                              &range_start, &range_end);
1559                         if (ret != 0)
1560                                 break;
1561                 }
1562 
1563                 dir_key.offset = range_start;
1564                 while (1) {
1565                         int nritems;
1566                         ret = btrfs_search_slot(NULL, root, &dir_key, path,
1567                                                 0, 0);
1568                         if (ret < 0)
1569                                 goto out;
1570 
1571                         nritems = btrfs_header_nritems(path->nodes[0]);
1572                         if (path->slots[0] >= nritems) {
1573                                 ret = btrfs_next_leaf(root, path);
1574                                 if (ret)
1575                                         break;
1576                         }
1577                         btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1578                                               path->slots[0]);
1579                         if (found_key.objectid != dirid ||
1580                             found_key.type != dir_key.type)
1581                                 goto next_type;
1582 
1583                         if (found_key.offset > range_end)
1584                                 break;
1585 
1586                         ret = check_item_in_log(trans, root, log, path,
1587                                                 log_path, dir,
1588                                                 &found_key);
1589                         BUG_ON(ret);
1590                         if (found_key.offset == (u64)-1)
1591                                 break;
1592                         dir_key.offset = found_key.offset + 1;
1593                 }
1594                 btrfs_release_path(path);
1595                 if (range_end == (u64)-1)
1596                         break;
1597                 range_start = range_end + 1;
1598         }
1599 
1600 next_type:
1601         ret = 0;
1602         if (key_type == BTRFS_DIR_LOG_ITEM_KEY) {
1603                 key_type = BTRFS_DIR_LOG_INDEX_KEY;
1604                 dir_key.type = BTRFS_DIR_INDEX_KEY;
1605                 btrfs_release_path(path);
1606                 goto again;
1607         }
1608 out:
1609         btrfs_release_path(path);
1610         btrfs_free_path(log_path);
1611         iput(dir);
1612         return ret;
1613 }
1614 
1615 /*
1616  * the process_func used to replay items from the log tree.  This
1617  * gets called in two different stages.  The first stage just looks
1618  * for inodes and makes sure they are all copied into the subvolume.
1619  *
1620  * The second stage copies all the other item types from the log into
1621  * the subvolume.  The two stage approach is slower, but gets rid of
1622  * lots of complexity around inodes referencing other inodes that exist
1623  * only in the log (references come from either directory items or inode
1624  * back refs).
1625  */
1626 static int replay_one_buffer(struct btrfs_root *log, struct extent_buffer *eb,
1627                              struct walk_control *wc, u64 gen)
1628 {
1629         int nritems;
1630         struct btrfs_path *path;
1631         struct btrfs_root *root = wc->replay_dest;
1632         struct btrfs_key key;
1633         int level;
1634         int i;
1635         int ret;
1636 
1637         ret = btrfs_read_buffer(eb, gen);
1638         if (ret)
1639                 return ret;
1640 
1641         level = btrfs_header_level(eb);
1642 
1643         if (level != 0)
1644                 return 0;
1645 
1646         path = btrfs_alloc_path();
1647         if (!path)
1648                 return -ENOMEM;
1649 
1650         nritems = btrfs_header_nritems(eb);
1651         for (i = 0; i < nritems; i++) {
1652                 btrfs_item_key_to_cpu(eb, &key, i);
1653 
1654                 /* inode keys are done during the first stage */
1655                 if (key.type == BTRFS_INODE_ITEM_KEY &&
1656                     wc->stage == LOG_WALK_REPLAY_INODES) {
1657                         struct btrfs_inode_item *inode_item;
1658                         u32 mode;
1659 
1660                         inode_item = btrfs_item_ptr(eb, i,
1661                                             struct btrfs_inode_item);
1662                         mode = btrfs_inode_mode(eb, inode_item);
1663                         if (S_ISDIR(mode)) {
1664                                 ret = replay_dir_deletes(wc->trans,
1665                                          root, log, path, key.objectid, 0);
1666                                 BUG_ON(ret);
1667                         }
1668                         ret = overwrite_item(wc->trans, root, path,
1669                                              eb, i, &key);
1670                         BUG_ON(ret);
1671 
1672                         /* for regular files, make sure corresponding
1673                          * orhpan item exist. extents past the new EOF
1674                          * will be truncated later by orphan cleanup.
1675                          */
1676                         if (S_ISREG(mode)) {
1677                                 ret = insert_orphan_item(wc->trans, root,
1678                                                          key.objectid);
1679                                 BUG_ON(ret);
1680                         }
1681 
1682                         ret = link_to_fixup_dir(wc->trans, root,
1683                                                 path, key.objectid);
1684                         BUG_ON(ret);
1685                 }
1686                 if (wc->stage < LOG_WALK_REPLAY_ALL)
1687                         continue;
1688 
1689                 /* these keys are simply copied */
1690                 if (key.type == BTRFS_XATTR_ITEM_KEY) {
1691                         ret = overwrite_item(wc->trans, root, path,
1692                                              eb, i, &key);
1693                         BUG_ON(ret);
1694                 } else if (key.type == BTRFS_INODE_REF_KEY) {
1695                         ret = add_inode_ref(wc->trans, root, log, path,
1696                                             eb, i, &key);
1697                         BUG_ON(ret && ret != -ENOENT);
1698                 } else if (key.type == BTRFS_EXTENT_DATA_KEY) {
1699                         ret = replay_one_extent(wc->trans, root, path,
1700                                                 eb, i, &key);
1701                         BUG_ON(ret);
1702                 } else if (key.type == BTRFS_DIR_ITEM_KEY ||
1703                            key.type == BTRFS_DIR_INDEX_KEY) {
1704                         ret = replay_one_dir_item(wc->trans, root, path,
1705                                                   eb, i, &key);
1706                         BUG_ON(ret);
1707                 }
1708         }
1709         btrfs_free_path(path);
1710         return 0;
1711 }
1712 
1713 static noinline int walk_down_log_tree(struct btrfs_trans_handle *trans,
1714                                    struct btrfs_root *root,
1715                                    struct btrfs_path *path, int *level,
1716                                    struct walk_control *wc)
1717 {
1718         u64 root_owner;
1719         u64 bytenr;
1720         u64 ptr_gen;
1721         struct extent_buffer *next;
1722         struct extent_buffer *cur;
1723         struct extent_buffer *parent;
1724         u32 blocksize;
1725         int ret = 0;
1726 
1727         WARN_ON(*level < 0);
1728         WARN_ON(*level >= BTRFS_MAX_LEVEL);
1729 
1730         while (*level > 0) {
1731                 WARN_ON(*level < 0);
1732                 WARN_ON(*level >= BTRFS_MAX_LEVEL);
1733                 cur = path->nodes[*level];
1734 
1735                 if (btrfs_header_level(cur) != *level)
1736                         WARN_ON(1);
1737 
1738                 if (path->slots[*level] >=
1739                     btrfs_header_nritems(cur))
1740                         break;
1741 
1742                 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
1743                 ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
1744                 blocksize = btrfs_level_size(root, *level - 1);
1745 
1746                 parent = path->nodes[*level];
1747                 root_owner = btrfs_header_owner(parent);
1748 
1749                 next = btrfs_find_create_tree_block(root, bytenr, blocksize);
1750                 if (!next)
1751                         return -ENOMEM;
1752 
1753                 if (*level == 1) {
1754                         ret = wc->process_func(root, next, wc, ptr_gen);
1755                         if (ret)
1756                                 return ret;
1757 
1758                         path->slots[*level]++;
1759                         if (wc->free) {
1760                                 ret = btrfs_read_buffer(next, ptr_gen);
1761                                 if (ret) {
1762                                         free_extent_buffer(next);
1763                                         return ret;
1764                                 }
1765 
1766                                 btrfs_tree_lock(next);
1767                                 btrfs_set_lock_blocking(next);
1768                                 clean_tree_block(trans, root, next);
1769                                 btrfs_wait_tree_block_writeback(next);
1770                                 btrfs_tree_unlock(next);
1771 
1772                                 WARN_ON(root_owner !=
1773                                         BTRFS_TREE_LOG_OBJECTID);
1774                                 ret = btrfs_free_and_pin_reserved_extent(root,
1775                                                          bytenr, blocksize);
1776                                 BUG_ON(ret); /* -ENOMEM or logic errors */
1777                         }
1778                         free_extent_buffer(next);
1779                         continue;
1780                 }
1781                 ret = btrfs_read_buffer(next, ptr_gen);
1782                 if (ret) {
1783                         free_extent_buffer(next);
1784                         return ret;
1785                 }
1786 
1787                 WARN_ON(*level <= 0);
1788                 if (path->nodes[*level-1])
1789                         free_extent_buffer(path->nodes[*level-1]);
1790                 path->nodes[*level-1] = next;
1791                 *level = btrfs_header_level(next);
1792                 path->slots[*level] = 0;
1793                 cond_resched();
1794         }
1795         WARN_ON(*level < 0);
1796         WARN_ON(*level >= BTRFS_MAX_LEVEL);
1797 
1798         path->slots[*level] = btrfs_header_nritems(path->nodes[*level]);
1799 
1800         cond_resched();
1801         return 0;
1802 }
1803 
1804 static noinline int walk_up_log_tree(struct btrfs_trans_handle *trans,
1805                                  struct btrfs_root *root,
1806                                  struct btrfs_path *path, int *level,
1807                                  struct walk_control *wc)
1808 {
1809         u64 root_owner;
1810         int i;
1811         int slot;
1812         int ret;
1813 
1814         for (i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
1815                 slot = path->slots[i];
1816                 if (slot + 1 < btrfs_header_nritems(path->nodes[i])) {
1817                         path->slots[i]++;
1818                         *level = i;
1819                         WARN_ON(*level == 0);
1820                         return 0;
1821                 } else {
1822                         struct extent_buffer *parent;
1823                         if (path->nodes[*level] == root->node)
1824                                 parent = path->nodes[*level];
1825                         else
1826                                 parent = path->nodes[*level + 1];
1827 
1828                         root_owner = btrfs_header_owner(parent);
1829                         ret = wc->process_func(root, path->nodes[*level], wc,
1830                                  btrfs_header_generation(path->nodes[*level]));
1831                         if (ret)
1832                                 return ret;
1833 
1834                         if (wc->free) {
1835                                 struct extent_buffer *next;
1836 
1837                                 next = path->nodes[*level];
1838 
1839                                 btrfs_tree_lock(next);
1840                                 btrfs_set_lock_blocking(next);
1841                                 clean_tree_block(trans, root, next);
1842                                 btrfs_wait_tree_block_writeback(next);
1843                                 btrfs_tree_unlock(next);
1844 
1845                                 WARN_ON(root_owner != BTRFS_TREE_LOG_OBJECTID);
1846                                 ret = btrfs_free_and_pin_reserved_extent(root,
1847                                                 path->nodes[*level]->start,
1848                                                 path->nodes[*level]->len);
1849                                 BUG_ON(ret);
1850                         }
1851                         free_extent_buffer(path->nodes[*level]);
1852                         path->nodes[*level] = NULL;
1853                         *level = i + 1;
1854                 }
1855         }
1856         return 1;
1857 }
1858 
1859 /*
1860  * drop the reference count on the tree rooted at 'snap'.  This traverses
1861  * the tree freeing any blocks that have a ref count of zero after being
1862  * decremented.
1863  */
1864 static int walk_log_tree(struct btrfs_trans_handle *trans,
1865                          struct btrfs_root *log, struct walk_control *wc)
1866 {
1867         int ret = 0;
1868         int wret;
1869         int level;
1870         struct btrfs_path *path;
1871         int i;
1872         int orig_level;
1873 
1874         path = btrfs_alloc_path();
1875         if (!path)
1876                 return -ENOMEM;
1877 
1878         level = btrfs_header_level(log->node);
1879         orig_level = level;
1880         path->nodes[level] = log->node;
1881         extent_buffer_get(log->node);
1882         path->slots[level] = 0;
1883 
1884         while (1) {
1885                 wret = walk_down_log_tree(trans, log, path, &level, wc);
1886                 if (wret > 0)
1887                         break;
1888                 if (wret < 0) {
1889                         ret = wret;
1890                         goto out;
1891                 }
1892 
1893                 wret = walk_up_log_tree(trans, log, path, &level, wc);
1894                 if (wret > 0)
1895                         break;
1896                 if (wret < 0) {
1897                         ret = wret;
1898                         goto out;
1899                 }
1900         }
1901 
1902         /* was the root node processed? if not, catch it here */
1903         if (path->nodes[orig_level]) {
1904                 ret = wc->process_func(log, path->nodes[orig_level], wc,
1905                          btrfs_header_generation(path->nodes[orig_level]));
1906                 if (ret)
1907                         goto out;
1908                 if (wc->free) {
1909                         struct extent_buffer *next;
1910 
1911                         next = path->nodes[orig_level];
1912 
1913                         btrfs_tree_lock(next);
1914                         btrfs_set_lock_blocking(next);
1915                         clean_tree_block(trans, log, next);
1916                         btrfs_wait_tree_block_writeback(next);
1917                         btrfs_tree_unlock(next);
1918 
1919                         WARN_ON(log->root_key.objectid !=
1920                                 BTRFS_TREE_LOG_OBJECTID);
1921                         ret = btrfs_free_and_pin_reserved_extent(log, next->start,
1922                                                          next->len);
1923                         BUG_ON(ret); /* -ENOMEM or logic errors */
1924                 }
1925         }
1926 
1927 out:
1928         for (i = 0; i <= orig_level; i++) {
1929                 if (path->nodes[i]) {
1930                         free_extent_buffer(path->nodes[i]);
1931                         path->nodes[i] = NULL;
1932                 }
1933         }
1934         btrfs_free_path(path);
1935         return ret;
1936 }
1937 
1938 /*
1939  * helper function to update the item for a given subvolumes log root
1940  * in the tree of log roots
1941  */
1942 static int update_log_root(struct btrfs_trans_handle *trans,
1943                            struct btrfs_root *log)
1944 {
1945         int ret;
1946 
1947         if (log->log_transid == 1) {
1948                 /* insert root item on the first sync */
1949                 ret = btrfs_insert_root(trans, log->fs_info->log_root_tree,
1950                                 &log->root_key, &log->root_item);
1951         } else {
1952                 ret = btrfs_update_root(trans, log->fs_info->log_root_tree,
1953                                 &log->root_key, &log->root_item);
1954         }
1955         return ret;
1956 }
1957 
1958 static int wait_log_commit(struct btrfs_trans_handle *trans,
1959                            struct btrfs_root *root, unsigned long transid)
1960 {
1961         DEFINE_WAIT(wait);
1962         int index = transid % 2;
1963 
1964         /*
1965          * we only allow two pending log transactions at a time,
1966          * so we know that if ours is more than 2 older than the
1967          * current transaction, we're done
1968          */
1969         do {
1970                 prepare_to_wait(&root->log_commit_wait[index],
1971                                 &wait, TASK_UNINTERRUPTIBLE);
1972                 mutex_unlock(&root->log_mutex);
1973 
1974                 if (root->fs_info->last_trans_log_full_commit !=
1975                     trans->transid && root->log_transid < transid + 2 &&
1976                     atomic_read(&root->log_commit[index]))
1977                         schedule();
1978 
1979                 finish_wait(&root->log_commit_wait[index], &wait);
1980                 mutex_lock(&root->log_mutex);
1981         } while (root->fs_info->last_trans_log_full_commit !=
1982                  trans->transid && root->log_transid < transid + 2 &&
1983                  atomic_read(&root->log_commit[index]));
1984         return 0;
1985 }
1986 
1987 static void wait_for_writer(struct btrfs_trans_handle *trans,
1988                             struct btrfs_root *root)
1989 {
1990         DEFINE_WAIT(wait);
1991         while (root->fs_info->last_trans_log_full_commit !=
1992                trans->transid && atomic_read(&root->log_writers)) {
1993                 prepare_to_wait(&root->log_writer_wait,
1994                                 &wait, TASK_UNINTERRUPTIBLE);
1995                 mutex_unlock(&root->log_mutex);
1996                 if (root->fs_info->last_trans_log_full_commit !=
1997                     trans->transid && atomic_read(&root->log_writers))
1998                         schedule();
1999                 mutex_lock(&root->log_mutex);
2000                 finish_wait(&root->log_writer_wait, &wait);
2001         }
2002 }
2003 
2004 /*
2005  * btrfs_sync_log does sends a given tree log down to the disk and
2006  * updates the super blocks to record it.  When this call is done,
2007  * you know that any inodes previously logged are safely on disk only
2008  * if it returns 0.
2009  *
2010  * Any other return value means you need to call btrfs_commit_transaction.
2011  * Some of the edge cases for fsyncing directories that have had unlinks
2012  * or renames done in the past mean that sometimes the only safe
2013  * fsync is to commit the whole FS.  When btrfs_sync_log returns -EAGAIN,
2014  * that has happened.
2015  */
2016 int btrfs_sync_log(struct btrfs_trans_handle *trans,
2017                    struct btrfs_root *root)
2018 {
2019         int index1;
2020         int index2;
2021         int mark;
2022         int ret;
2023         struct btrfs_root *log = root->log_root;
2024         struct btrfs_root *log_root_tree = root->fs_info->log_root_tree;
2025         unsigned long log_transid = 0;
2026 
2027         mutex_lock(&root->log_mutex);
2028         index1 = root->log_transid % 2;
2029         if (atomic_read(&root->log_commit[index1])) {
2030                 wait_log_commit(trans, root, root->log_transid);
2031                 mutex_unlock(&root->log_mutex);
2032                 return 0;
2033         }
2034         atomic_set(&root->log_commit[index1], 1);
2035 
2036         /* wait for previous tree log sync to complete */
2037         if (atomic_read(&root->log_commit[(index1 + 1) % 2]))
2038                 wait_log_commit(trans, root, root->log_transid - 1);
2039         while (1) {
2040                 unsigned long batch = root->log_batch;
2041                 /* when we're on an ssd, just kick the log commit out */
2042                 if (!btrfs_test_opt(root, SSD) && root->log_multiple_pids) {
2043                         mutex_unlock(&root->log_mutex);
2044                         schedule_timeout_uninterruptible(1);
2045                         mutex_lock(&root->log_mutex);
2046                 }
2047                 wait_for_writer(trans, root);
2048                 if (batch == root->log_batch)
2049                         break;
2050         }
2051 
2052         /* bail out if we need to do a full commit */
2053         if (root->fs_info->last_trans_log_full_commit == trans->transid) {
2054                 ret = -EAGAIN;
2055                 mutex_unlock(&root->log_mutex);
2056                 goto out;
2057         }
2058 
2059         log_transid = root->log_transid;
2060         if (log_transid % 2 == 0)
2061                 mark = EXTENT_DIRTY;
2062         else
2063                 mark = EXTENT_NEW;
2064 
2065         /* we start IO on  all the marked extents here, but we don't actually
2066          * wait for them until later.
2067          */
2068         ret = btrfs_write_marked_extents(log, &log->dirty_log_pages, mark);
2069         if (ret) {
2070                 btrfs_abort_transaction(trans, root, ret);
2071                 mutex_unlock(&root->log_mutex);
2072                 goto out;
2073         }
2074 
2075         btrfs_set_root_node(&log->root_item, log->node);
2076 
2077         root->log_batch = 0;
2078         root->log_transid++;
2079         log->log_transid = root->log_transid;
2080         root->log_start_pid = 0;
2081         smp_mb();
2082         /*
2083          * IO has been started, blocks of the log tree have WRITTEN flag set
2084          * in their headers. new modifications of the log will be written to
2085          * new positions. so it's safe to allow log writers to go in.
2086          */
2087         mutex_unlock(&root->log_mutex);
2088 
2089         mutex_lock(&log_root_tree->log_mutex);
2090         log_root_tree->log_batch++;
2091         atomic_inc(&log_root_tree->log_writers);
2092         mutex_unlock(&log_root_tree->log_mutex);
2093 
2094         ret = update_log_root(trans, log);
2095 
2096         mutex_lock(&log_root_tree->log_mutex);
2097         if (atomic_dec_and_test(&log_root_tree->log_writers)) {
2098                 smp_mb();
2099                 if (waitqueue_active(&log_root_tree->log_writer_wait))
2100                         wake_up(&log_root_tree->log_writer_wait);
2101         }
2102 
2103         if (ret) {
2104                 if (ret != -ENOSPC) {
2105                         btrfs_abort_transaction(trans, root, ret);
2106                         mutex_unlock(&log_root_tree->log_mutex);
2107                         goto out;
2108                 }
2109                 root->fs_info->last_trans_log_full_commit = trans->transid;
2110                 btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark);
2111                 mutex_unlock(&log_root_tree->log_mutex);
2112                 ret = -EAGAIN;
2113                 goto out;
2114         }
2115 
2116         index2 = log_root_tree->log_transid % 2;
2117         if (atomic_read(&log_root_tree->log_commit[index2])) {
2118                 btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark);
2119                 wait_log_commit(trans, log_root_tree,
2120                                 log_root_tree->log_transid);
2121                 mutex_unlock(&log_root_tree->log_mutex);
2122                 ret = 0;
2123                 goto out;
2124         }
2125         atomic_set(&log_root_tree->log_commit[index2], 1);
2126 
2127         if (atomic_read(&log_root_tree->log_commit[(index2 + 1) % 2])) {
2128                 wait_log_commit(trans, log_root_tree,
2129                                 log_root_tree->log_transid - 1);
2130         }
2131 
2132         wait_for_writer(trans, log_root_tree);
2133 
2134         /*
2135          * now that we've moved on to the tree of log tree roots,
2136          * check the full commit flag again
2137          */
2138         if (root->fs_info->last_trans_log_full_commit == trans->transid) {
2139                 btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark);
2140                 mutex_unlock(&log_root_tree->log_mutex);
2141                 ret = -EAGAIN;
2142                 goto out_wake_log_root;
2143         }
2144 
2145         ret = btrfs_write_and_wait_marked_extents(log_root_tree,
2146                                 &log_root_tree->dirty_log_pages,
2147                                 EXTENT_DIRTY | EXTENT_NEW);
2148         if (ret) {
2149                 btrfs_abort_transaction(trans, root, ret);
2150                 mutex_unlock(&log_root_tree->log_mutex);
2151                 goto out_wake_log_root;
2152         }
2153         btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark);
2154 
2155         btrfs_set_super_log_root(root->fs_info->super_for_commit,
2156                                 log_root_tree->node->start);
2157         btrfs_set_super_log_root_level(root->fs_info->super_for_commit,
2158                                 btrfs_header_level(log_root_tree->node));
2159 
2160         log_root_tree->log_batch = 0;
2161         log_root_tree->log_transid++;
2162         smp_mb();
2163 
2164         mutex_unlock(&log_root_tree->log_mutex);
2165 
2166         /*
2167          * nobody else is going to jump in and write the the ctree
2168          * super here because the log_commit atomic below is protecting
2169          * us.  We must be called with a transaction handle pinning
2170          * the running transaction open, so a full commit can't hop
2171          * in and cause problems either.
2172          */
2173         btrfs_scrub_pause_super(root);
2174         write_ctree_super(trans, root->fs_info->tree_root, 1);
2175         btrfs_scrub_continue_super(root);
2176         ret = 0;
2177 
2178         mutex_lock(&root->log_mutex);
2179         if (root->last_log_commit < log_transid)
2180                 root->last_log_commit = log_transid;
2181         mutex_unlock(&root->log_mutex);
2182 
2183 out_wake_log_root:
2184         atomic_set(&log_root_tree->log_commit[index2], 0);
2185         smp_mb();
2186         if (waitqueue_active(&log_root_tree->log_commit_wait[index2]))
2187                 wake_up(&log_root_tree->log_commit_wait[index2]);
2188 out:
2189         atomic_set(&root->log_commit[index1], 0);
2190         smp_mb();
2191         if (waitqueue_active(&root->log_commit_wait[index1]))
2192                 wake_up(&root->log_commit_wait[index1]);
2193         return ret;
2194 }
2195 
2196 static void free_log_tree(struct btrfs_trans_handle *trans,
2197                           struct btrfs_root *log)
2198 {
2199         int ret;
2200         u64 start;
2201         u64 end;
2202         struct walk_control wc = {
2203                 .free = 1,
2204                 .process_func = process_one_buffer
2205         };
2206 
2207         ret = walk_log_tree(trans, log, &wc);
2208         BUG_ON(ret);
2209 
2210         while (1) {
2211                 ret = find_first_extent_bit(&log->dirty_log_pages,
2212                                 0, &start, &end, EXTENT_DIRTY | EXTENT_NEW);
2213                 if (ret)
2214                         break;
2215 
2216                 clear_extent_bits(&log->dirty_log_pages, start, end,
2217                                   EXTENT_DIRTY | EXTENT_NEW, GFP_NOFS);
2218         }
2219 
2220         free_extent_buffer(log->node);
2221         kfree(log);
2222 }
2223 
2224 /*
2225  * free all the extents used by the tree log.  This should be called
2226  * at commit time of the full transaction
2227  */
2228 int btrfs_free_log(struct btrfs_trans_handle *trans, struct btrfs_root *root)
2229 {
2230         if (root->log_root) {
2231                 free_log_tree(trans, root->log_root);
2232                 root->log_root = NULL;
2233         }
2234         return 0;
2235 }
2236 
2237 int btrfs_free_log_root_tree(struct btrfs_trans_handle *trans,
2238                              struct btrfs_fs_info *fs_info)
2239 {
2240         if (fs_info->log_root_tree) {
2241                 free_log_tree(trans, fs_info->log_root_tree);
2242                 fs_info->log_root_tree = NULL;
2243         }
2244         return 0;
2245 }
2246 
2247 /*
2248  * If both a file and directory are logged, and unlinks or renames are
2249  * mixed in, we have a few interesting corners:
2250  *
2251  * create file X in dir Y
2252  * link file X to X.link in dir Y
2253  * fsync file X
2254  * unlink file X but leave X.link
2255  * fsync dir Y
2256  *
2257  * After a crash we would expect only X.link to exist.  But file X
2258  * didn't get fsync'd again so the log has back refs for X and X.link.
2259  *
2260  * We solve this by removing directory entries and inode backrefs from the
2261  * log when a file that was logged in the current transaction is
2262  * unlinked.  Any later fsync will include the updated log entries, and
2263  * we'll be able to reconstruct the proper directory items from backrefs.
2264  *
2265  * This optimizations allows us to avoid relogging the entire inode
2266  * or the entire directory.
2267  */
2268 int btrfs_del_dir_entries_in_log(struct btrfs_trans_handle *trans,
2269                                  struct btrfs_root *root,
2270                                  const char *name, int name_len,
2271                                  struct inode *dir, u64 index)
2272 {
2273         struct btrfs_root *log;
2274         struct btrfs_dir_item *di;
2275         struct btrfs_path *path;
2276         int ret;
2277         int err = 0;
2278         int bytes_del = 0;
2279         u64 dir_ino = btrfs_ino(dir);
2280 
2281         if (BTRFS_I(dir)->logged_trans < trans->transid)
2282                 return 0;
2283 
2284         ret = join_running_log_trans(root);
2285         if (ret)
2286                 return 0;
2287 
2288         mutex_lock(&BTRFS_I(dir)->log_mutex);
2289 
2290         log = root->log_root;
2291         path = btrfs_alloc_path();
2292         if (!path) {
2293                 err = -ENOMEM;
2294                 goto out_unlock;
2295         }
2296 
2297         di = btrfs_lookup_dir_item(trans, log, path, dir_ino,
2298                                    name, name_len, -1);
2299         if (IS_ERR(di)) {
2300                 err = PTR_ERR(di);
2301                 goto fail;
2302         }
2303         if (di) {
2304                 ret = btrfs_delete_one_dir_name(trans, log, path, di);
2305                 bytes_del += name_len;
2306                 BUG_ON(ret);
2307         }
2308         btrfs_release_path(path);
2309         di = btrfs_lookup_dir_index_item(trans, log, path, dir_ino,
2310                                          index, name, name_len, -1);
2311         if (IS_ERR(di)) {
2312                 err = PTR_ERR(di);
2313                 goto fail;
2314         }
2315         if (di) {
2316                 ret = btrfs_delete_one_dir_name(trans, log, path, di);
2317                 bytes_del += name_len;
2318                 BUG_ON(ret);
2319         }
2320 
2321         /* update the directory size in the log to reflect the names
2322          * we have removed
2323          */
2324         if (bytes_del) {
2325                 struct btrfs_key key;
2326 
2327                 key.objectid = dir_ino;
2328                 key.offset = 0;
2329                 key.type = BTRFS_INODE_ITEM_KEY;
2330                 btrfs_release_path(path);
2331 
2332                 ret = btrfs_search_slot(trans, log, &key, path, 0, 1);
2333                 if (ret < 0) {
2334                         err = ret;
2335                         goto fail;
2336                 }
2337                 if (ret == 0) {
2338                         struct btrfs_inode_item *item;
2339                         u64 i_size;
2340 
2341                         item = btrfs_item_ptr(path->nodes[0], path->slots[0],
2342                                               struct btrfs_inode_item);
2343                         i_size = btrfs_inode_size(path->nodes[0], item);
2344                         if (i_size > bytes_del)
2345                                 i_size -= bytes_del;
2346                         else
2347                                 i_size = 0;
2348                         btrfs_set_inode_size(path->nodes[0], item, i_size);
2349                         btrfs_mark_buffer_dirty(path->nodes[0]);
2350                 } else
2351                         ret = 0;
2352                 btrfs_release_path(path);
2353         }
2354 fail:
2355         btrfs_free_path(path);
2356 out_unlock:
2357         mutex_unlock(&BTRFS_I(dir)->log_mutex);
2358         if (ret == -ENOSPC) {
2359                 root->fs_info->last_trans_log_full_commit = trans->transid;
2360                 ret = 0;
2361         } else if (ret < 0)
2362                 btrfs_abort_transaction(trans, root, ret);
2363 
2364         btrfs_end_log_trans(root);
2365 
2366         return err;
2367 }
2368 
2369 /* see comments for btrfs_del_dir_entries_in_log */
2370 int btrfs_del_inode_ref_in_log(struct btrfs_trans_handle *trans,
2371                                struct btrfs_root *root,
2372                                const char *name, int name_len,
2373                                struct inode *inode, u64 dirid)
2374 {
2375         struct btrfs_root *log;
2376         u64 index;
2377         int ret;
2378 
2379         if (BTRFS_I(inode)->logged_trans < trans->transid)
2380                 return 0;
2381 
2382         ret = join_running_log_trans(root);
2383         if (ret)
2384                 return 0;
2385         log = root->log_root;
2386         mutex_lock(&BTRFS_I(inode)->log_mutex);
2387 
2388         ret = btrfs_del_inode_ref(trans, log, name, name_len, btrfs_ino(inode),
2389                                   dirid, &index);
2390         mutex_unlock(&BTRFS_I(inode)->log_mutex);
2391         if (ret == -ENOSPC) {
2392                 root->fs_info->last_trans_log_full_commit = trans->transid;
2393                 ret = 0;
2394         } else if (ret < 0 && ret != -ENOENT)
2395                 btrfs_abort_transaction(trans, root, ret);
2396         btrfs_end_log_trans(root);
2397 
2398         return ret;
2399 }
2400 
2401 /*
2402  * creates a range item in the log for 'dirid'.  first_offset and
2403  * last_offset tell us which parts of the key space the log should
2404  * be considered authoritative for.
2405  */
2406 static noinline int insert_dir_log_key(struct btrfs_trans_handle *trans,
2407                                        struct btrfs_root *log,
2408                                        struct btrfs_path *path,
2409                                        int key_type, u64 dirid,
2410                                        u64 first_offset, u64 last_offset)
2411 {
2412         int ret;
2413         struct btrfs_key key;
2414         struct btrfs_dir_log_item *item;
2415 
2416         key.objectid = dirid;
2417         key.offset = first_offset;
2418         if (key_type == BTRFS_DIR_ITEM_KEY)
2419                 key.type = BTRFS_DIR_LOG_ITEM_KEY;
2420         else
2421                 key.type = BTRFS_DIR_LOG_INDEX_KEY;
2422         ret = btrfs_insert_empty_item(trans, log, path, &key, sizeof(*item));
2423         if (ret)
2424                 return ret;
2425 
2426         item = btrfs_item_ptr(path->nodes[0], path->slots[0],
2427                               struct btrfs_dir_log_item);
2428         btrfs_set_dir_log_end(path->nodes[0], item, last_offset);
2429         btrfs_mark_buffer_dirty(path->nodes[0]);
2430         btrfs_release_path(path);
2431         return 0;
2432 }
2433 
2434 /*
2435  * log all the items included in the current transaction for a given
2436  * directory.  This also creates the range items in the log tree required
2437  * to replay anything deleted before the fsync
2438  */
2439 static noinline int log_dir_items(struct btrfs_trans_handle *trans,
2440                           struct btrfs_root *root, struct inode *inode,
2441                           struct btrfs_path *path,
2442                           struct btrfs_path *dst_path, int key_type,
2443                           u64 min_offset, u64 *last_offset_ret)
2444 {
2445         struct btrfs_key min_key;
2446         struct btrfs_key max_key;
2447         struct btrfs_root *log = root->log_root;
2448         struct extent_buffer *src;
2449         int err = 0;
2450         int ret;
2451         int i;
2452         int nritems;
2453         u64 first_offset = min_offset;
2454         u64 last_offset = (u64)-1;
2455         u64 ino = btrfs_ino(inode);
2456 
2457         log = root->log_root;
2458         max_key.objectid = ino;
2459         max_key.offset = (u64)-1;
2460         max_key.type = key_type;
2461 
2462         min_key.objectid = ino;
2463         min_key.type = key_type;
2464         min_key.offset = min_offset;
2465 
2466         path->keep_locks = 1;
2467 
2468         ret = btrfs_search_forward(root, &min_key, &max_key,
2469                                    path, 0, trans->transid);
2470 
2471         /*
2472          * we didn't find anything from this transaction, see if there
2473          * is anything at all
2474          */
2475         if (ret != 0 || min_key.objectid != ino || min_key.type != key_type) {
2476                 min_key.objectid = ino;
2477                 min_key.type = key_type;
2478                 min_key.offset = (u64)-1;
2479                 btrfs_release_path(path);
2480                 ret = btrfs_search_slot(NULL, root, &min_key, path, 0, 0);
2481                 if (ret < 0) {
2482                         btrfs_release_path(path);
2483                         return ret;
2484                 }
2485                 ret = btrfs_previous_item(root, path, ino, key_type);
2486 
2487                 /* if ret == 0 there are items for this type,
2488                  * create a range to tell us the last key of this type.
2489                  * otherwise, there are no items in this directory after
2490                  * *min_offset, and we create a range to indicate that.
2491                  */
2492                 if (ret == 0) {
2493                         struct btrfs_key tmp;
2494                         btrfs_item_key_to_cpu(path->nodes[0], &tmp,
2495                                               path->slots[0]);
2496                         if (key_type == tmp.type)
2497                                 first_offset = max(min_offset, tmp.offset) + 1;
2498                 }
2499                 goto done;
2500         }
2501 
2502         /* go backward to find any previous key */
2503         ret = btrfs_previous_item(root, path, ino, key_type);
2504         if (ret == 0) {
2505                 struct btrfs_key tmp;
2506                 btrfs_item_key_to_cpu(path->nodes[0], &tmp, path->slots[0]);
2507                 if (key_type == tmp.type) {
2508                         first_offset = tmp.offset;
2509                         ret = overwrite_item(trans, log, dst_path,
2510                                              path->nodes[0], path->slots[0],
2511                                              &tmp);
2512                         if (ret) {
2513                                 err = ret;
2514                                 goto done;
2515                         }
2516                 }
2517         }
2518         btrfs_release_path(path);
2519 
2520         /* find the first key from this transaction again */
2521         ret = btrfs_search_slot(NULL, root, &min_key, path, 0, 0);
2522         if (ret != 0) {
2523                 WARN_ON(1);
2524                 goto done;
2525         }
2526 
2527         /*
2528          * we have a block from this transaction, log every item in it
2529          * from our directory
2530          */
2531         while (1) {
2532                 struct btrfs_key tmp;
2533                 src = path->nodes[0];
2534                 nritems = btrfs_header_nritems(src);
2535                 for (i = path->slots[0]; i < nritems; i++) {
2536                         btrfs_item_key_to_cpu(src, &min_key, i);
2537 
2538                         if (min_key.objectid != ino || min_key.type != key_type)
2539                                 goto done;
2540                         ret = overwrite_item(trans, log, dst_path, src, i,
2541                                              &min_key);
2542                         if (ret) {
2543                                 err = ret;
2544                                 goto done;
2545                         }
2546                 }
2547                 path->slots[0] = nritems;
2548 
2549                 /*
2550                  * look ahead to the next item and see if it is also
2551                  * from this directory and from this transaction
2552                  */
2553                 ret = btrfs_next_leaf(root, path);
2554                 if (ret == 1) {
2555                         last_offset = (u64)-1;
2556                         goto done;
2557                 }
2558                 btrfs_item_key_to_cpu(path->nodes[0], &tmp, path->slots[0]);
2559                 if (tmp.objectid != ino || tmp.type != key_type) {
2560                         last_offset = (u64)-1;
2561                         goto done;
2562                 }
2563                 if (btrfs_header_generation(path->nodes[0]) != trans->transid) {
2564                         ret = overwrite_item(trans, log, dst_path,
2565                                              path->nodes[0], path->slots[0],
2566                                              &tmp);
2567                         if (ret)
2568                                 err = ret;
2569                         else
2570                                 last_offset = tmp.offset;
2571                         goto done;
2572                 }
2573         }
2574 done:
2575         btrfs_release_path(path);
2576         btrfs_release_path(dst_path);
2577 
2578         if (err == 0) {
2579                 *last_offset_ret = last_offset;
2580                 /*
2581                  * insert the log range keys to indicate where the log
2582                  * is valid
2583                  */
2584                 ret = insert_dir_log_key(trans, log, path, key_type,
2585                                          ino, first_offset, last_offset);
2586                 if (ret)
2587                         err = ret;
2588         }
2589         return err;
2590 }
2591 
2592 /*
2593  * logging directories is very similar to logging inodes, We find all the items
2594  * from the current transaction and write them to the log.
2595  *
2596  * The recovery code scans the directory in the subvolume, and if it finds a
2597  * key in the range logged that is not present in the log tree, then it means
2598  * that dir entry was unlinked during the transaction.
2599  *
2600  * In order for that scan to work, we must include one key smaller than
2601  * the smallest logged by this transaction and one key larger than the largest
2602  * key logged by this transaction.
2603  */
2604 static noinline int log_directory_changes(struct btrfs_trans_handle *trans,
2605                           struct btrfs_root *root, struct inode *inode,
2606                           struct btrfs_path *path,
2607                           struct btrfs_path *dst_path)
2608 {
2609         u64 min_key;
2610         u64 max_key;
2611         int ret;
2612         int key_type = BTRFS_DIR_ITEM_KEY;
2613 
2614 again:
2615         min_key = 0;
2616         max_key = 0;
2617         while (1) {
2618                 ret = log_dir_items(trans, root, inode, path,
2619                                     dst_path, key_type, min_key,
2620                                     &max_key);
2621                 if (ret)
2622                         return ret;
2623                 if (max_key == (u64)-1)
2624                         break;
2625                 min_key = max_key + 1;
2626         }
2627 
2628         if (key_type == BTRFS_DIR_ITEM_KEY) {
2629                 key_type = BTRFS_DIR_INDEX_KEY;
2630                 goto again;
2631         }
2632         return 0;
2633 }
2634 
2635 /*
2636  * a helper function to drop items from the log before we relog an
2637  * inode.  max_key_type indicates the highest item type to remove.
2638  * This cannot be run for file data extents because it does not
2639  * free the extents they point to.
2640  */
2641 static int drop_objectid_items(struct btrfs_trans_handle *trans,
2642                                   struct btrfs_root *log,
2643                                   struct btrfs_path *path,
2644                                   u64 objectid, int max_key_type)
2645 {
2646         int ret;
2647         struct btrfs_key key;
2648         struct btrfs_key found_key;
2649 
2650         key.objectid = objectid;
2651         key.type = max_key_type;
2652         key.offset = (u64)-1;
2653 
2654         while (1) {
2655                 ret = btrfs_search_slot(trans, log, &key, path, -1, 1);
2656                 BUG_ON(ret == 0);
2657                 if (ret < 0)
2658                         break;
2659 
2660                 if (path->slots[0] == 0)
2661                         break;
2662 
2663                 path->slots[0]--;
2664                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
2665                                       path->slots[0]);
2666 
2667                 if (found_key.objectid != objectid)
2668                         break;
2669 
2670                 ret = btrfs_del_item(trans, log, path);
2671                 if (ret)
2672                         break;
2673                 btrfs_release_path(path);
2674         }
2675         btrfs_release_path(path);
2676         if (ret > 0)
2677                 ret = 0;
2678         return ret;
2679 }
2680 
2681 static noinline int copy_items(struct btrfs_trans_handle *trans,
2682                                struct btrfs_root *log,
2683                                struct btrfs_path *dst_path,
2684                                struct extent_buffer *src,
2685                                int start_slot, int nr, int inode_only)
2686 {
2687         unsigned long src_offset;
2688         unsigned long dst_offset;
2689         struct btrfs_file_extent_item *extent;
2690         struct btrfs_inode_item *inode_item;
2691         int ret;
2692         struct btrfs_key *ins_keys;
2693         u32 *ins_sizes;
2694         char *ins_data;
2695         int i;
2696         struct list_head ordered_sums;
2697 
2698         INIT_LIST_HEAD(&ordered_sums);
2699 
2700         ins_data = kmalloc(nr * sizeof(struct btrfs_key) +
2701                            nr * sizeof(u32), GFP_NOFS);
2702         if (!ins_data)
2703                 return -ENOMEM;
2704 
2705         ins_sizes = (u32 *)ins_data;
2706         ins_keys = (struct btrfs_key *)(ins_data + nr * sizeof(u32));
2707 
2708         for (i = 0; i < nr; i++) {
2709                 ins_sizes[i] = btrfs_item_size_nr(src, i + start_slot);
2710                 btrfs_item_key_to_cpu(src, ins_keys + i, i + start_slot);
2711         }
2712         ret = btrfs_insert_empty_items(trans, log, dst_path,
2713                                        ins_keys, ins_sizes, nr);
2714         if (ret) {
2715                 kfree(ins_data);
2716                 return ret;
2717         }
2718 
2719         for (i = 0; i < nr; i++, dst_path->slots[0]++) {
2720                 dst_offset = btrfs_item_ptr_offset(dst_path->nodes[0],
2721                                                    dst_path->slots[0]);
2722 
2723                 src_offset = btrfs_item_ptr_offset(src, start_slot + i);
2724 
2725                 copy_extent_buffer(dst_path->nodes[0], src, dst_offset,
2726                                    src_offset, ins_sizes[i]);
2727 
2728                 if (inode_only == LOG_INODE_EXISTS &&
2729                     ins_keys[i].type == BTRFS_INODE_ITEM_KEY) {
2730                         inode_item = btrfs_item_ptr(dst_path->nodes[0],
2731                                                     dst_path->slots[0],
2732                                                     struct btrfs_inode_item);
2733                         btrfs_set_inode_size(dst_path->nodes[0], inode_item, 0);
2734 
2735                         /* set the generation to zero so the recover code
2736                          * can tell the difference between an logging
2737                          * just to say 'this inode exists' and a logging
2738                          * to say 'update this inode with these values'
2739                          */
2740                         btrfs_set_inode_generation(dst_path->nodes[0],
2741                                                    inode_item, 0);
2742                 }
2743                 /* take a reference on file data extents so that truncates
2744                  * or deletes of this inode don't have to relog the inode
2745                  * again
2746                  */
2747                 if (btrfs_key_type(ins_keys + i) == BTRFS_EXTENT_DATA_KEY) {
2748                         int found_type;
2749                         extent = btrfs_item_ptr(src, start_slot + i,
2750                                                 struct btrfs_file_extent_item);
2751 
2752                         if (btrfs_file_extent_generation(src, extent) < trans->transid)
2753                                 continue;
2754 
2755                         found_type = btrfs_file_extent_type(src, extent);
2756                         if (found_type == BTRFS_FILE_EXTENT_REG ||
2757                             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
2758                                 u64 ds, dl, cs, cl;
2759                                 ds = btrfs_file_extent_disk_bytenr(src,
2760                                                                 extent);
2761                                 /* ds == 0 is a hole */
2762                                 if (ds == 0)
2763                                         continue;
2764 
2765                                 dl = btrfs_file_extent_disk_num_bytes(src,
2766                                                                 extent);
2767                                 cs = btrfs_file_extent_offset(src, extent);
2768                                 cl = btrfs_file_extent_num_bytes(src,
2769                                                                 extent);
2770                                 if (btrfs_file_extent_compression(src,
2771                                                                   extent)) {
2772                                         cs = 0;
2773                                         cl = dl;
2774                                 }
2775 
2776                                 ret = btrfs_lookup_csums_range(
2777                                                 log->fs_info->csum_root,
2778                                                 ds + cs, ds + cs + cl - 1,
2779                                                 &ordered_sums, 0);
2780                                 BUG_ON(ret);
2781                         }
2782                 }
2783         }
2784 
2785         btrfs_mark_buffer_dirty(dst_path->nodes[0]);
2786         btrfs_release_path(dst_path);
2787         kfree(ins_data);
2788 
2789         /*
2790          * we have to do this after the loop above to avoid changing the
2791          * log tree while trying to change the log tree.
2792          */
2793         ret = 0;
2794         while (!list_empty(&ordered_sums)) {
2795                 struct btrfs_ordered_sum *sums = list_entry(ordered_sums.next,
2796                                                    struct btrfs_ordered_sum,
2797                                                    list);
2798                 if (!ret)
2799                         ret = btrfs_csum_file_blocks(trans, log, sums);
2800                 list_del(&sums->list);
2801                 kfree(sums);
2802         }
2803         return ret;
2804 }
2805 
2806 /* log a single inode in the tree log.
2807  * At least one parent directory for this inode must exist in the tree
2808  * or be logged already.
2809  *
2810  * Any items from this inode changed by the current transaction are copied
2811  * to the log tree.  An extra reference is taken on any extents in this
2812  * file, allowing us to avoid a whole pile of corner cases around logging
2813  * blocks that have been removed from the tree.
2814  *
2815  * See LOG_INODE_ALL and related defines for a description of what inode_only
2816  * does.
2817  *
2818  * This handles both files and directories.
2819  */
2820 static int btrfs_log_inode(struct btrfs_trans_handle *trans,
2821                              struct btrfs_root *root, struct inode *inode,
2822                              int inode_only)
2823 {
2824         struct btrfs_path *path;
2825         struct btrfs_path *dst_path;
2826         struct btrfs_key min_key;
2827         struct btrfs_key max_key;
2828         struct btrfs_root *log = root->log_root;
2829         struct extent_buffer *src = NULL;
2830         int err = 0;
2831         int ret;
2832         int nritems;
2833         int ins_start_slot = 0;
2834         int ins_nr;
2835         u64 ino = btrfs_ino(inode);
2836 
2837         log = root->log_root;
2838 
2839         path = btrfs_alloc_path();
2840         if (!path)
2841                 return -ENOMEM;
2842         dst_path = btrfs_alloc_path();
2843         if (!dst_path) {
2844                 btrfs_free_path(path);
2845                 return -ENOMEM;
2846         }
2847 
2848         min_key.objectid = ino;
2849         min_key.type = BTRFS_INODE_ITEM_KEY;
2850         min_key.offset = 0;
2851 
2852         max_key.objectid = ino;
2853 
2854         /* today the code can only do partial logging of directories */
2855         if (!S_ISDIR(inode->i_mode))
2856             inode_only = LOG_INODE_ALL;
2857 
2858         if (inode_only == LOG_INODE_EXISTS || S_ISDIR(inode->i_mode))
2859                 max_key.type = BTRFS_XATTR_ITEM_KEY;
2860         else
2861                 max_key.type = (u8)-1;
2862         max_key.offset = (u64)-1;
2863 
2864         ret = btrfs_commit_inode_delayed_items(trans, inode);
2865         if (ret) {
2866                 btrfs_free_path(path);
2867                 btrfs_free_path(dst_path);
2868                 return ret;
2869         }
2870 
2871         mutex_lock(&BTRFS_I(inode)->log_mutex);
2872 
2873         /*
2874          * a brute force approach to making sure we get the most uptodate
2875          * copies of everything.
2876          */
2877         if (S_ISDIR(inode->i_mode)) {
2878                 int max_key_type = BTRFS_DIR_LOG_INDEX_KEY;
2879 
2880                 if (inode_only == LOG_INODE_EXISTS)
2881                         max_key_type = BTRFS_XATTR_ITEM_KEY;
2882                 ret = drop_objectid_items(trans, log, path, ino, max_key_type);
2883         } else {
2884                 ret = btrfs_truncate_inode_items(trans, log, inode, 0, 0);
2885         }
2886         if (ret) {
2887                 err = ret;
2888                 goto out_unlock;
2889         }
2890         path->keep_locks = 1;
2891 
2892         while (1) {
2893                 ins_nr = 0;
2894                 ret = btrfs_search_forward(root, &min_key, &max_key,
2895                                            path, 0, trans->transid);
2896                 if (ret != 0)
2897                         break;
2898 again:
2899                 /* note, ins_nr might be > 0 here, cleanup outside the loop */
2900                 if (min_key.objectid != ino)
2901                         break;
2902                 if (min_key.type > max_key.type)
2903                         break;
2904 
2905                 src = path->nodes[0];
2906                 if (ins_nr && ins_start_slot + ins_nr == path->slots[0]) {
2907                         ins_nr++;
2908                         goto next_slot;
2909                 } else if (!ins_nr) {
2910                         ins_start_slot = path->slots[0];
2911                         ins_nr = 1;
2912                         goto next_slot;
2913                 }
2914 
2915                 ret = copy_items(trans, log, dst_path, src, ins_start_slot,
2916                                  ins_nr, inode_only);
2917                 if (ret) {
2918                         err = ret;
2919                         goto out_unlock;
2920                 }
2921                 ins_nr = 1;
2922                 ins_start_slot = path->slots[0];
2923 next_slot:
2924 
2925                 nritems = btrfs_header_nritems(path->nodes[0]);
2926                 path->slots[0]++;
2927                 if (path->slots[0] < nritems) {
2928                         btrfs_item_key_to_cpu(path->nodes[0], &min_key,
2929                                               path->slots[0]);
2930                         goto again;
2931                 }
2932                 if (ins_nr) {
2933                         ret = copy_items(trans, log, dst_path, src,
2934                                          ins_start_slot,
2935                                          ins_nr, inode_only);
2936                         if (ret) {
2937                                 err = ret;
2938                                 goto out_unlock;
2939                         }
2940                         ins_nr = 0;
2941                 }
2942                 btrfs_release_path(path);
2943 
2944                 if (min_key.offset < (u64)-1)
2945                         min_key.offset++;
2946                 else if (min_key.type < (u8)-1)
2947                         min_key.type++;
2948                 else if (min_key.objectid < (u64)-1)
2949                         min_key.objectid++;
2950                 else
2951                         break;
2952         }
2953         if (ins_nr) {
2954                 ret = copy_items(trans, log, dst_path, src,
2955                                  ins_start_slot,
2956                                  ins_nr, inode_only);
2957                 if (ret) {
2958                         err = ret;
2959                         goto out_unlock;
2960                 }
2961                 ins_nr = 0;
2962         }
2963         WARN_ON(ins_nr);
2964         if (inode_only == LOG_INODE_ALL && S_ISDIR(inode->i_mode)) {
2965                 btrfs_release_path(path);
2966                 btrfs_release_path(dst_path);
2967                 ret = log_directory_changes(trans, root, inode, path, dst_path);
2968                 if (ret) {
2969                         err = ret;
2970                         goto out_unlock;
2971                 }
2972         }
2973         BTRFS_I(inode)->logged_trans = trans->transid;
2974 out_unlock:
2975         mutex_unlock(&BTRFS_I(inode)->log_mutex);
2976 
2977         btrfs_free_path(path);
2978         btrfs_free_path(dst_path);
2979         return err;
2980 }
2981 
2982 /*
2983  * follow the dentry parent pointers up the chain and see if any
2984  * of the directories in it require a full commit before they can
2985  * be logged.  Returns zero if nothing special needs to be done or 1 if
2986  * a full commit is required.
2987  */
2988 static noinline int check_parent_dirs_for_sync(struct btrfs_trans_handle *trans,
2989                                                struct inode *inode,
2990                                                struct dentry *parent,
2991                                                struct super_block *sb,
2992                                                u64 last_committed)
2993 {
2994         int ret = 0;
2995         struct btrfs_root *root;
2996         struct dentry *old_parent = NULL;
2997 
2998         /*
2999          * for regular files, if its inode is already on disk, we don't
3000          * have to worry about the parents at all.  This is because
3001          * we can use the last_unlink_trans field to record renames
3002          * and other fun in this file.
3003          */
3004         if (S_ISREG(inode->i_mode) &&
3005             BTRFS_I(inode)->generation <= last_committed &&
3006             BTRFS_I(inode)->last_unlink_trans <= last_committed)
3007                         goto out;
3008 
3009         if (!S_ISDIR(inode->i_mode)) {
3010                 if (!parent || !parent->d_inode || sb != parent->d_inode->i_sb)
3011                         goto out;
3012                 inode = parent->d_inode;
3013         }
3014 
3015         while (1) {
3016                 BTRFS_I(inode)->logged_trans = trans->transid;
3017                 smp_mb();
3018 
3019                 if (BTRFS_I(inode)->last_unlink_trans > last_committed) {
3020                         root = BTRFS_I(inode)->root;
3021 
3022                         /*
3023                          * make sure any commits to the log are forced
3024                          * to be full commits
3025                          */
3026                         root->fs_info->last_trans_log_full_commit =
3027                                 trans->transid;
3028                         ret = 1;
3029                         break;
3030                 }
3031 
3032                 if (!parent || !parent->d_inode || sb != parent->d_inode->i_sb)
3033                         break;
3034 
3035                 if (IS_ROOT(parent))
3036                         break;
3037 
3038                 parent = dget_parent(parent);
3039                 dput(old_parent);
3040                 old_parent = parent;
3041                 inode = parent->d_inode;
3042 
3043         }
3044         dput(old_parent);
3045 out:
3046         return ret;
3047 }
3048 
3049 /*
3050  * helper function around btrfs_log_inode to make sure newly created
3051  * parent directories also end up in the log.  A minimal inode and backref
3052  * only logging is done of any parent directories that are older than
3053  * the last committed transaction
3054  */
3055 int btrfs_log_inode_parent(struct btrfs_trans_handle *trans,
3056                     struct btrfs_root *root, struct inode *inode,
3057                     struct dentry *parent, int exists_only)
3058 {
3059         int inode_only = exists_only ? LOG_INODE_EXISTS : LOG_INODE_ALL;
3060         struct super_block *sb;
3061         struct dentry *old_parent = NULL;
3062         int ret = 0;
3063         u64 last_committed = root->fs_info->last_trans_committed;
3064 
3065         sb = inode->i_sb;
3066 
3067         if (btrfs_test_opt(root, NOTREELOG)) {
3068                 ret = 1;
3069                 goto end_no_trans;
3070         }
3071 
3072         if (root->fs_info->last_trans_log_full_commit >
3073             root->fs_info->last_trans_committed) {
3074                 ret = 1;
3075                 goto end_no_trans;
3076         }
3077 
3078         if (root != BTRFS_I(inode)->root ||
3079             btrfs_root_refs(&root->root_item) == 0) {
3080                 ret = 1;
3081                 goto end_no_trans;
3082         }
3083 
3084         ret = check_parent_dirs_for_sync(trans, inode, parent,
3085                                          sb, last_committed);
3086         if (ret)
3087                 goto end_no_trans;
3088 
3089         if (btrfs_inode_in_log(inode, trans->transid)) {
3090                 ret = BTRFS_NO_LOG_SYNC;
3091                 goto end_no_trans;
3092         }
3093 
3094         ret = start_log_trans(trans, root);
3095         if (ret)
3096                 goto end_trans;
3097 
3098         ret = btrfs_log_inode(trans, root, inode, inode_only);
3099         if (ret)
3100                 goto end_trans;
3101 
3102         /*
3103          * for regular files, if its inode is already on disk, we don't
3104          * have to worry about the parents at all.  This is because
3105          * we can use the last_unlink_trans field to record renames
3106          * and other fun in this file.
3107          */
3108         if (S_ISREG(inode->i_mode) &&
3109             BTRFS_I(inode)->generation <= last_committed &&
3110             BTRFS_I(inode)->last_unlink_trans <= last_committed) {
3111                 ret = 0;
3112                 goto end_trans;
3113         }
3114 
3115         inode_only = LOG_INODE_EXISTS;
3116         while (1) {
3117                 if (!parent || !parent->d_inode || sb != parent->d_inode->i_sb)
3118                         break;
3119 
3120                 inode = parent->d_inode;
3121                 if (root != BTRFS_I(inode)->root)
3122                         break;
3123 
3124                 if (BTRFS_I(inode)->generation >
3125                     root->fs_info->last_trans_committed) {
3126                         ret = btrfs_log_inode(trans, root, inode, inode_only);
3127                         if (ret)
3128                                 goto end_trans;
3129                 }
3130                 if (IS_ROOT(parent))
3131                         break;
3132 
3133                 parent = dget_parent(parent);
3134                 dput(old_parent);
3135                 old_parent = parent;
3136         }
3137         ret = 0;
3138 end_trans:
3139         dput(old_parent);
3140         if (ret < 0) {
3141                 BUG_ON(ret != -ENOSPC);
3142                 root->fs_info->last_trans_log_full_commit = trans->transid;
3143                 ret = 1;
3144         }
3145         btrfs_end_log_trans(root);
3146 end_no_trans:
3147         return ret;
3148 }
3149 
3150 /*
3151  * it is not safe to log dentry if the chunk root has added new
3152  * chunks.  This returns 0 if the dentry was logged, and 1 otherwise.
3153  * If this returns 1, you must commit the transaction to safely get your
3154  * data on disk.
3155  */
3156 int btrfs_log_dentry_safe(struct btrfs_trans_handle *trans,
3157                           struct btrfs_root *root, struct dentry *dentry)
3158 {
3159         struct dentry *parent = dget_parent(dentry);
3160         int ret;
3161 
3162         ret = btrfs_log_inode_parent(trans, root, dentry->d_inode, parent, 0);
3163         dput(parent);
3164 
3165         return ret;
3166 }
3167 
3168 /*
3169  * should be called during mount to recover any replay any log trees
3170  * from the FS
3171  */
3172 int btrfs_recover_log_trees(struct btrfs_root *log_root_tree)
3173 {
3174         int ret;
3175         struct btrfs_path *path;
3176         struct btrfs_trans_handle *trans;
3177         struct btrfs_key key;
3178         struct btrfs_key found_key;
3179         struct btrfs_key tmp_key;
3180         struct btrfs_root *log;
3181         struct btrfs_fs_info *fs_info = log_root_tree->fs_info;
3182         struct walk_control wc = {
3183                 .process_func = process_one_buffer,
3184                 .stage = 0,
3185         };
3186 
3187         path = btrfs_alloc_path();
3188         if (!path)
3189                 return -ENOMEM;
3190 
3191         fs_info->log_root_recovering = 1;
3192 
3193         trans = btrfs_start_transaction(fs_info->tree_root, 0);
3194         if (IS_ERR(trans)) {
3195                 ret = PTR_ERR(trans);
3196                 goto error;
3197         }
3198 
3199         wc.trans = trans;
3200         wc.pin = 1;
3201 
3202         ret = walk_log_tree(trans, log_root_tree, &wc);
3203         if (ret) {
3204                 btrfs_error(fs_info, ret, "Failed to pin buffers while "
3205                             "recovering log root tree.");
3206                 goto error;
3207         }
3208 
3209 again:
3210         key.objectid = BTRFS_TREE_LOG_OBJECTID;
3211         key.offset = (u64)-1;
3212         btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
3213 
3214         while (1) {
3215                 ret = btrfs_search_slot(NULL, log_root_tree, &key, path, 0, 0);
3216 
3217                 if (ret < 0) {
3218                         btrfs_error(fs_info, ret,
3219                                     "Couldn't find tree log root.");
3220                         goto error;
3221                 }
3222                 if (ret > 0) {
3223                         if (path->slots[0] == 0)
3224                                 break;
3225                         path->slots[0]--;
3226                 }
3227                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
3228                                       path->slots[0]);
3229                 btrfs_release_path(path);
3230                 if (found_key.objectid != BTRFS_TREE_LOG_OBJECTID)
3231                         break;
3232 
3233                 log = btrfs_read_fs_root_no_radix(log_root_tree,
3234                                                   &found_key);
3235                 if (IS_ERR(log)) {
3236                         ret = PTR_ERR(log);
3237                         btrfs_error(fs_info, ret,
3238                                     "Couldn't read tree log root.");
3239                         goto error;
3240                 }
3241 
3242                 tmp_key.objectid = found_key.offset;
3243                 tmp_key.type = BTRFS_ROOT_ITEM_KEY;
3244                 tmp_key.offset = (u64)-1;
3245 
3246                 wc.replay_dest = btrfs_read_fs_root_no_name(fs_info, &tmp_key);
3247                 if (IS_ERR(wc.replay_dest)) {
3248                         ret = PTR_ERR(wc.replay_dest);
3249                         btrfs_error(fs_info, ret, "Couldn't read target root "
3250                                     "for tree log recovery.");
3251                         goto error;
3252                 }
3253 
3254                 wc.replay_dest->log_root = log;
3255                 btrfs_record_root_in_trans(trans, wc.replay_dest);
3256                 ret = walk_log_tree(trans, log, &wc);
3257                 BUG_ON(ret);
3258 
3259                 if (wc.stage == LOG_WALK_REPLAY_ALL) {
3260                         ret = fixup_inode_link_counts(trans, wc.replay_dest,
3261                                                       path);
3262                         BUG_ON(ret);
3263                 }
3264 
3265                 key.offset = found_key.offset - 1;
3266                 wc.replay_dest->log_root = NULL;
3267                 free_extent_buffer(log->node);
3268                 free_extent_buffer(log->commit_root);
3269                 kfree(log);
3270 
3271                 if (found_key.offset == 0)
3272                         break;
3273         }
3274         btrfs_release_path(path);
3275 
3276         /* step one is to pin it all, step two is to replay just inodes */
3277         if (wc.pin) {
3278                 wc.pin = 0;
3279                 wc.process_func = replay_one_buffer;
3280                 wc.stage = LOG_WALK_REPLAY_INODES;
3281                 goto again;
3282         }
3283         /* step three is to replay everything */
3284         if (wc.stage < LOG_WALK_REPLAY_ALL) {
3285                 wc.stage++;
3286                 goto again;
3287         }
3288 
3289         btrfs_free_path(path);
3290 
3291         free_extent_buffer(log_root_tree->node);
3292         log_root_tree->log_root = NULL;
3293         fs_info->log_root_recovering = 0;
3294 
3295         /* step 4: commit the transaction, which also unpins the blocks */
3296         btrfs_commit_transaction(trans, fs_info->tree_root);
3297 
3298         kfree(log_root_tree);
3299         return 0;
3300 
3301 error:
3302         btrfs_free_path(path);
3303         return ret;
3304 }
3305 
3306 /*
3307  * there are some corner cases where we want to force a full
3308  * commit instead of allowing a directory to be logged.
3309  *
3310  * They revolve around files there were unlinked from the directory, and
3311  * this function updates the parent directory so that a full commit is
3312  * properly done if it is fsync'd later after the unlinks are done.
3313  */
3314 void btrfs_record_unlink_dir(struct btrfs_trans_handle *trans,
3315                              struct inode *dir, struct inode *inode,
3316                              int for_rename)
3317 {
3318         /*
3319          * when we're logging a file, if it hasn't been renamed
3320          * or unlinked, and its inode is fully committed on disk,
3321          * we don't have to worry about walking up the directory chain
3322          * to log its parents.
3323          *
3324          * So, we use the last_unlink_trans field to put this transid
3325          * into the file.  When the file is logged we check it and
3326          * don't log the parents if the file is fully on disk.
3327          */
3328         if (S_ISREG(inode->i_mode))
3329                 BTRFS_I(inode)->last_unlink_trans = trans->transid;
3330 
3331         /*
3332          * if this directory was already logged any new
3333          * names for this file/dir will get recorded
3334          */
3335         smp_mb();
3336         if (BTRFS_I(dir)->logged_trans == trans->transid)
3337                 return;
3338 
3339         /*
3340          * if the inode we're about to unlink was logged,
3341          * the log will be properly updated for any new names
3342          */
3343         if (BTRFS_I(inode)->logged_trans == trans->transid)
3344                 return;
3345 
3346         /*
3347          * when renaming files across directories, if the directory
3348          * there we're unlinking from gets fsync'd later on, there's
3349          * no way to find the destination directory later and fsync it
3350          * properly.  So, we have to be conservative and force commits
3351          * so the new name gets discovered.
3352          */
3353         if (for_rename)
3354                 goto record;
3355 
3356         /* we can safely do the unlink without any special recording */
3357         return;
3358 
3359 record:
3360         BTRFS_I(dir)->last_unlink_trans = trans->transid;
3361 }
3362 
3363 /*
3364  * Call this after adding a new name for a file and it will properly
3365  * update the log to reflect the new name.
3366  *
3367  * It will return zero if all goes well, and it will return 1 if a
3368  * full transaction commit is required.
3369  */
3370 int btrfs_log_new_name(struct btrfs_trans_handle *trans,
3371                         struct inode *inode, struct inode *old_dir,
3372                         struct dentry *parent)
3373 {
3374         struct btrfs_root * root = BTRFS_I(inode)->root;
3375 
3376         /*
3377          * this will force the logging code to walk the dentry chain
3378          * up for the file
3379          */
3380         if (S_ISREG(inode->i_mode))
3381                 BTRFS_I(inode)->last_unlink_trans = trans->transid;
3382 
3383         /*
3384          * if this inode hasn't been logged and directory we're renaming it
3385          * from hasn't been logged, we don't need to log it
3386          */
3387         if (BTRFS_I(inode)->logged_trans <=
3388             root->fs_info->last_trans_committed &&
3389             (!old_dir || BTRFS_I(old_dir)->logged_trans <=
3390                     root->fs_info->last_trans_committed))
3391                 return 0;
3392 
3393         return btrfs_log_inode_parent(trans, root, inode, parent, 1);
3394 }
3395 
3396 

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