Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable
[linux-2.6.git] / fs / btrfs / extent-tree.c
1 /*
2  * Copyright (C) 2007 Oracle.  All rights reserved.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public
6  * License v2 as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
11  * General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public
14  * License along with this program; if not, write to the
15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16  * Boston, MA 021110-1307, USA.
17  */
18 #include <linux/sched.h>
19 #include <linux/pagemap.h>
20 #include <linux/writeback.h>
21 #include <linux/blkdev.h>
22 #include <linux/sort.h>
23 #include <linux/rcupdate.h>
24 #include <linux/kthread.h>
25 #include "compat.h"
26 #include "hash.h"
27 #include "ctree.h"
28 #include "disk-io.h"
29 #include "print-tree.h"
30 #include "transaction.h"
31 #include "volumes.h"
32 #include "locking.h"
33 #include "free-space-cache.h"
34
35 static int update_block_group(struct btrfs_trans_handle *trans,
36                               struct btrfs_root *root,
37                               u64 bytenr, u64 num_bytes, int alloc,
38                               int mark_free);
39 static int update_reserved_extents(struct btrfs_block_group_cache *cache,
40                                    u64 num_bytes, int reserve);
41 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
42                                 struct btrfs_root *root,
43                                 u64 bytenr, u64 num_bytes, u64 parent,
44                                 u64 root_objectid, u64 owner_objectid,
45                                 u64 owner_offset, int refs_to_drop,
46                                 struct btrfs_delayed_extent_op *extra_op);
47 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
48                                     struct extent_buffer *leaf,
49                                     struct btrfs_extent_item *ei);
50 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
51                                       struct btrfs_root *root,
52                                       u64 parent, u64 root_objectid,
53                                       u64 flags, u64 owner, u64 offset,
54                                       struct btrfs_key *ins, int ref_mod);
55 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
56                                      struct btrfs_root *root,
57                                      u64 parent, u64 root_objectid,
58                                      u64 flags, struct btrfs_disk_key *key,
59                                      int level, struct btrfs_key *ins);
60 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
61                           struct btrfs_root *extent_root, u64 alloc_bytes,
62                           u64 flags, int force);
63 static int pin_down_bytes(struct btrfs_trans_handle *trans,
64                           struct btrfs_root *root,
65                           struct btrfs_path *path,
66                           u64 bytenr, u64 num_bytes,
67                           int is_data, int reserved,
68                           struct extent_buffer **must_clean);
69 static int find_next_key(struct btrfs_path *path, int level,
70                          struct btrfs_key *key);
71 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
72                             int dump_block_groups);
73
74 static noinline int
75 block_group_cache_done(struct btrfs_block_group_cache *cache)
76 {
77         smp_mb();
78         return cache->cached == BTRFS_CACHE_FINISHED;
79 }
80
81 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
82 {
83         return (cache->flags & bits) == bits;
84 }
85
86 /*
87  * this adds the block group to the fs_info rb tree for the block group
88  * cache
89  */
90 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
91                                 struct btrfs_block_group_cache *block_group)
92 {
93         struct rb_node **p;
94         struct rb_node *parent = NULL;
95         struct btrfs_block_group_cache *cache;
96
97         spin_lock(&info->block_group_cache_lock);
98         p = &info->block_group_cache_tree.rb_node;
99
100         while (*p) {
101                 parent = *p;
102                 cache = rb_entry(parent, struct btrfs_block_group_cache,
103                                  cache_node);
104                 if (block_group->key.objectid < cache->key.objectid) {
105                         p = &(*p)->rb_left;
106                 } else if (block_group->key.objectid > cache->key.objectid) {
107                         p = &(*p)->rb_right;
108                 } else {
109                         spin_unlock(&info->block_group_cache_lock);
110                         return -EEXIST;
111                 }
112         }
113
114         rb_link_node(&block_group->cache_node, parent, p);
115         rb_insert_color(&block_group->cache_node,
116                         &info->block_group_cache_tree);
117         spin_unlock(&info->block_group_cache_lock);
118
119         return 0;
120 }
121
122 /*
123  * This will return the block group at or after bytenr if contains is 0, else
124  * it will return the block group that contains the bytenr
125  */
126 static struct btrfs_block_group_cache *
127 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
128                               int contains)
129 {
130         struct btrfs_block_group_cache *cache, *ret = NULL;
131         struct rb_node *n;
132         u64 end, start;
133
134         spin_lock(&info->block_group_cache_lock);
135         n = info->block_group_cache_tree.rb_node;
136
137         while (n) {
138                 cache = rb_entry(n, struct btrfs_block_group_cache,
139                                  cache_node);
140                 end = cache->key.objectid + cache->key.offset - 1;
141                 start = cache->key.objectid;
142
143                 if (bytenr < start) {
144                         if (!contains && (!ret || start < ret->key.objectid))
145                                 ret = cache;
146                         n = n->rb_left;
147                 } else if (bytenr > start) {
148                         if (contains && bytenr <= end) {
149                                 ret = cache;
150                                 break;
151                         }
152                         n = n->rb_right;
153                 } else {
154                         ret = cache;
155                         break;
156                 }
157         }
158         if (ret)
159                 atomic_inc(&ret->count);
160         spin_unlock(&info->block_group_cache_lock);
161
162         return ret;
163 }
164
165 static int add_excluded_extent(struct btrfs_root *root,
166                                u64 start, u64 num_bytes)
167 {
168         u64 end = start + num_bytes - 1;
169         set_extent_bits(&root->fs_info->freed_extents[0],
170                         start, end, EXTENT_UPTODATE, GFP_NOFS);
171         set_extent_bits(&root->fs_info->freed_extents[1],
172                         start, end, EXTENT_UPTODATE, GFP_NOFS);
173         return 0;
174 }
175
176 static void free_excluded_extents(struct btrfs_root *root,
177                                   struct btrfs_block_group_cache *cache)
178 {
179         u64 start, end;
180
181         start = cache->key.objectid;
182         end = start + cache->key.offset - 1;
183
184         clear_extent_bits(&root->fs_info->freed_extents[0],
185                           start, end, EXTENT_UPTODATE, GFP_NOFS);
186         clear_extent_bits(&root->fs_info->freed_extents[1],
187                           start, end, EXTENT_UPTODATE, GFP_NOFS);
188 }
189
190 static int exclude_super_stripes(struct btrfs_root *root,
191                                  struct btrfs_block_group_cache *cache)
192 {
193         u64 bytenr;
194         u64 *logical;
195         int stripe_len;
196         int i, nr, ret;
197
198         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
199                 bytenr = btrfs_sb_offset(i);
200                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
201                                        cache->key.objectid, bytenr,
202                                        0, &logical, &nr, &stripe_len);
203                 BUG_ON(ret);
204
205                 while (nr--) {
206                         cache->bytes_super += stripe_len;
207                         ret = add_excluded_extent(root, logical[nr],
208                                                   stripe_len);
209                         BUG_ON(ret);
210                 }
211
212                 kfree(logical);
213         }
214         return 0;
215 }
216
217 static struct btrfs_caching_control *
218 get_caching_control(struct btrfs_block_group_cache *cache)
219 {
220         struct btrfs_caching_control *ctl;
221
222         spin_lock(&cache->lock);
223         if (cache->cached != BTRFS_CACHE_STARTED) {
224                 spin_unlock(&cache->lock);
225                 return NULL;
226         }
227
228         ctl = cache->caching_ctl;
229         atomic_inc(&ctl->count);
230         spin_unlock(&cache->lock);
231         return ctl;
232 }
233
234 static void put_caching_control(struct btrfs_caching_control *ctl)
235 {
236         if (atomic_dec_and_test(&ctl->count))
237                 kfree(ctl);
238 }
239
240 /*
241  * this is only called by cache_block_group, since we could have freed extents
242  * we need to check the pinned_extents for any extents that can't be used yet
243  * since their free space will be released as soon as the transaction commits.
244  */
245 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
246                               struct btrfs_fs_info *info, u64 start, u64 end)
247 {
248         u64 extent_start, extent_end, size, total_added = 0;
249         int ret;
250
251         while (start < end) {
252                 ret = find_first_extent_bit(info->pinned_extents, start,
253                                             &extent_start, &extent_end,
254                                             EXTENT_DIRTY | EXTENT_UPTODATE);
255                 if (ret)
256                         break;
257
258                 if (extent_start == start) {
259                         start = extent_end + 1;
260                 } else if (extent_start > start && extent_start < end) {
261                         size = extent_start - start;
262                         total_added += size;
263                         ret = btrfs_add_free_space(block_group, start,
264                                                    size);
265                         BUG_ON(ret);
266                         start = extent_end + 1;
267                 } else {
268                         break;
269                 }
270         }
271
272         if (start < end) {
273                 size = end - start;
274                 total_added += size;
275                 ret = btrfs_add_free_space(block_group, start, size);
276                 BUG_ON(ret);
277         }
278
279         return total_added;
280 }
281
282 static int caching_kthread(void *data)
283 {
284         struct btrfs_block_group_cache *block_group = data;
285         struct btrfs_fs_info *fs_info = block_group->fs_info;
286         struct btrfs_caching_control *caching_ctl = block_group->caching_ctl;
287         struct btrfs_root *extent_root = fs_info->extent_root;
288         struct btrfs_path *path;
289         struct extent_buffer *leaf;
290         struct btrfs_key key;
291         u64 total_found = 0;
292         u64 last = 0;
293         u32 nritems;
294         int ret = 0;
295
296         path = btrfs_alloc_path();
297         if (!path)
298                 return -ENOMEM;
299
300         exclude_super_stripes(extent_root, block_group);
301         spin_lock(&block_group->space_info->lock);
302         block_group->space_info->bytes_super += block_group->bytes_super;
303         spin_unlock(&block_group->space_info->lock);
304
305         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
306
307         /*
308          * We don't want to deadlock with somebody trying to allocate a new
309          * extent for the extent root while also trying to search the extent
310          * root to add free space.  So we skip locking and search the commit
311          * root, since its read-only
312          */
313         path->skip_locking = 1;
314         path->search_commit_root = 1;
315         path->reada = 2;
316
317         key.objectid = last;
318         key.offset = 0;
319         key.type = BTRFS_EXTENT_ITEM_KEY;
320 again:
321         mutex_lock(&caching_ctl->mutex);
322         /* need to make sure the commit_root doesn't disappear */
323         down_read(&fs_info->extent_commit_sem);
324
325         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
326         if (ret < 0)
327                 goto err;
328
329         leaf = path->nodes[0];
330         nritems = btrfs_header_nritems(leaf);
331
332         while (1) {
333                 smp_mb();
334                 if (fs_info->closing > 1) {
335                         last = (u64)-1;
336                         break;
337                 }
338
339                 if (path->slots[0] < nritems) {
340                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
341                 } else {
342                         ret = find_next_key(path, 0, &key);
343                         if (ret)
344                                 break;
345
346                         caching_ctl->progress = last;
347                         btrfs_release_path(extent_root, path);
348                         up_read(&fs_info->extent_commit_sem);
349                         mutex_unlock(&caching_ctl->mutex);
350                         if (btrfs_transaction_in_commit(fs_info))
351                                 schedule_timeout(1);
352                         else
353                                 cond_resched();
354                         goto again;
355                 }
356
357                 if (key.objectid < block_group->key.objectid) {
358                         path->slots[0]++;
359                         continue;
360                 }
361
362                 if (key.objectid >= block_group->key.objectid +
363                     block_group->key.offset)
364                         break;
365
366                 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
367                         total_found += add_new_free_space(block_group,
368                                                           fs_info, last,
369                                                           key.objectid);
370                         last = key.objectid + key.offset;
371
372                         if (total_found > (1024 * 1024 * 2)) {
373                                 total_found = 0;
374                                 wake_up(&caching_ctl->wait);
375                         }
376                 }
377                 path->slots[0]++;
378         }
379         ret = 0;
380
381         total_found += add_new_free_space(block_group, fs_info, last,
382                                           block_group->key.objectid +
383                                           block_group->key.offset);
384         caching_ctl->progress = (u64)-1;
385
386         spin_lock(&block_group->lock);
387         block_group->caching_ctl = NULL;
388         block_group->cached = BTRFS_CACHE_FINISHED;
389         spin_unlock(&block_group->lock);
390
391 err:
392         btrfs_free_path(path);
393         up_read(&fs_info->extent_commit_sem);
394
395         free_excluded_extents(extent_root, block_group);
396
397         mutex_unlock(&caching_ctl->mutex);
398         wake_up(&caching_ctl->wait);
399
400         put_caching_control(caching_ctl);
401         atomic_dec(&block_group->space_info->caching_threads);
402         return 0;
403 }
404
405 static int cache_block_group(struct btrfs_block_group_cache *cache)
406 {
407         struct btrfs_fs_info *fs_info = cache->fs_info;
408         struct btrfs_caching_control *caching_ctl;
409         struct task_struct *tsk;
410         int ret = 0;
411
412         smp_mb();
413         if (cache->cached != BTRFS_CACHE_NO)
414                 return 0;
415
416         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_KERNEL);
417         BUG_ON(!caching_ctl);
418
419         INIT_LIST_HEAD(&caching_ctl->list);
420         mutex_init(&caching_ctl->mutex);
421         init_waitqueue_head(&caching_ctl->wait);
422         caching_ctl->block_group = cache;
423         caching_ctl->progress = cache->key.objectid;
424         /* one for caching kthread, one for caching block group list */
425         atomic_set(&caching_ctl->count, 2);
426
427         spin_lock(&cache->lock);
428         if (cache->cached != BTRFS_CACHE_NO) {
429                 spin_unlock(&cache->lock);
430                 kfree(caching_ctl);
431                 return 0;
432         }
433         cache->caching_ctl = caching_ctl;
434         cache->cached = BTRFS_CACHE_STARTED;
435         spin_unlock(&cache->lock);
436
437         down_write(&fs_info->extent_commit_sem);
438         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
439         up_write(&fs_info->extent_commit_sem);
440
441         atomic_inc(&cache->space_info->caching_threads);
442
443         tsk = kthread_run(caching_kthread, cache, "btrfs-cache-%llu\n",
444                           cache->key.objectid);
445         if (IS_ERR(tsk)) {
446                 ret = PTR_ERR(tsk);
447                 printk(KERN_ERR "error running thread %d\n", ret);
448                 BUG();
449         }
450
451         return ret;
452 }
453
454 /*
455  * return the block group that starts at or after bytenr
456  */
457 static struct btrfs_block_group_cache *
458 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
459 {
460         struct btrfs_block_group_cache *cache;
461
462         cache = block_group_cache_tree_search(info, bytenr, 0);
463
464         return cache;
465 }
466
467 /*
468  * return the block group that contains the given bytenr
469  */
470 struct btrfs_block_group_cache *btrfs_lookup_block_group(
471                                                  struct btrfs_fs_info *info,
472                                                  u64 bytenr)
473 {
474         struct btrfs_block_group_cache *cache;
475
476         cache = block_group_cache_tree_search(info, bytenr, 1);
477
478         return cache;
479 }
480
481 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
482 {
483         if (atomic_dec_and_test(&cache->count))
484                 kfree(cache);
485 }
486
487 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
488                                                   u64 flags)
489 {
490         struct list_head *head = &info->space_info;
491         struct btrfs_space_info *found;
492
493         rcu_read_lock();
494         list_for_each_entry_rcu(found, head, list) {
495                 if (found->flags == flags) {
496                         rcu_read_unlock();
497                         return found;
498                 }
499         }
500         rcu_read_unlock();
501         return NULL;
502 }
503
504 /*
505  * after adding space to the filesystem, we need to clear the full flags
506  * on all the space infos.
507  */
508 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
509 {
510         struct list_head *head = &info->space_info;
511         struct btrfs_space_info *found;
512
513         rcu_read_lock();
514         list_for_each_entry_rcu(found, head, list)
515                 found->full = 0;
516         rcu_read_unlock();
517 }
518
519 static u64 div_factor(u64 num, int factor)
520 {
521         if (factor == 10)
522                 return num;
523         num *= factor;
524         do_div(num, 10);
525         return num;
526 }
527
528 u64 btrfs_find_block_group(struct btrfs_root *root,
529                            u64 search_start, u64 search_hint, int owner)
530 {
531         struct btrfs_block_group_cache *cache;
532         u64 used;
533         u64 last = max(search_hint, search_start);
534         u64 group_start = 0;
535         int full_search = 0;
536         int factor = 9;
537         int wrapped = 0;
538 again:
539         while (1) {
540                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
541                 if (!cache)
542                         break;
543
544                 spin_lock(&cache->lock);
545                 last = cache->key.objectid + cache->key.offset;
546                 used = btrfs_block_group_used(&cache->item);
547
548                 if ((full_search || !cache->ro) &&
549                     block_group_bits(cache, BTRFS_BLOCK_GROUP_METADATA)) {
550                         if (used + cache->pinned + cache->reserved <
551                             div_factor(cache->key.offset, factor)) {
552                                 group_start = cache->key.objectid;
553                                 spin_unlock(&cache->lock);
554                                 btrfs_put_block_group(cache);
555                                 goto found;
556                         }
557                 }
558                 spin_unlock(&cache->lock);
559                 btrfs_put_block_group(cache);
560                 cond_resched();
561         }
562         if (!wrapped) {
563                 last = search_start;
564                 wrapped = 1;
565                 goto again;
566         }
567         if (!full_search && factor < 10) {
568                 last = search_start;
569                 full_search = 1;
570                 factor = 10;
571                 goto again;
572         }
573 found:
574         return group_start;
575 }
576
577 /* simple helper to search for an existing extent at a given offset */
578 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
579 {
580         int ret;
581         struct btrfs_key key;
582         struct btrfs_path *path;
583
584         path = btrfs_alloc_path();
585         BUG_ON(!path);
586         key.objectid = start;
587         key.offset = len;
588         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
589         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
590                                 0, 0);
591         btrfs_free_path(path);
592         return ret;
593 }
594
595 /*
596  * Back reference rules.  Back refs have three main goals:
597  *
598  * 1) differentiate between all holders of references to an extent so that
599  *    when a reference is dropped we can make sure it was a valid reference
600  *    before freeing the extent.
601  *
602  * 2) Provide enough information to quickly find the holders of an extent
603  *    if we notice a given block is corrupted or bad.
604  *
605  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
606  *    maintenance.  This is actually the same as #2, but with a slightly
607  *    different use case.
608  *
609  * There are two kinds of back refs. The implicit back refs is optimized
610  * for pointers in non-shared tree blocks. For a given pointer in a block,
611  * back refs of this kind provide information about the block's owner tree
612  * and the pointer's key. These information allow us to find the block by
613  * b-tree searching. The full back refs is for pointers in tree blocks not
614  * referenced by their owner trees. The location of tree block is recorded
615  * in the back refs. Actually the full back refs is generic, and can be
616  * used in all cases the implicit back refs is used. The major shortcoming
617  * of the full back refs is its overhead. Every time a tree block gets
618  * COWed, we have to update back refs entry for all pointers in it.
619  *
620  * For a newly allocated tree block, we use implicit back refs for
621  * pointers in it. This means most tree related operations only involve
622  * implicit back refs. For a tree block created in old transaction, the
623  * only way to drop a reference to it is COW it. So we can detect the
624  * event that tree block loses its owner tree's reference and do the
625  * back refs conversion.
626  *
627  * When a tree block is COW'd through a tree, there are four cases:
628  *
629  * The reference count of the block is one and the tree is the block's
630  * owner tree. Nothing to do in this case.
631  *
632  * The reference count of the block is one and the tree is not the
633  * block's owner tree. In this case, full back refs is used for pointers
634  * in the block. Remove these full back refs, add implicit back refs for
635  * every pointers in the new block.
636  *
637  * The reference count of the block is greater than one and the tree is
638  * the block's owner tree. In this case, implicit back refs is used for
639  * pointers in the block. Add full back refs for every pointers in the
640  * block, increase lower level extents' reference counts. The original
641  * implicit back refs are entailed to the new block.
642  *
643  * The reference count of the block is greater than one and the tree is
644  * not the block's owner tree. Add implicit back refs for every pointer in
645  * the new block, increase lower level extents' reference count.
646  *
647  * Back Reference Key composing:
648  *
649  * The key objectid corresponds to the first byte in the extent,
650  * The key type is used to differentiate between types of back refs.
651  * There are different meanings of the key offset for different types
652  * of back refs.
653  *
654  * File extents can be referenced by:
655  *
656  * - multiple snapshots, subvolumes, or different generations in one subvol
657  * - different files inside a single subvolume
658  * - different offsets inside a file (bookend extents in file.c)
659  *
660  * The extent ref structure for the implicit back refs has fields for:
661  *
662  * - Objectid of the subvolume root
663  * - objectid of the file holding the reference
664  * - original offset in the file
665  * - how many bookend extents
666  *
667  * The key offset for the implicit back refs is hash of the first
668  * three fields.
669  *
670  * The extent ref structure for the full back refs has field for:
671  *
672  * - number of pointers in the tree leaf
673  *
674  * The key offset for the implicit back refs is the first byte of
675  * the tree leaf
676  *
677  * When a file extent is allocated, The implicit back refs is used.
678  * the fields are filled in:
679  *
680  *     (root_key.objectid, inode objectid, offset in file, 1)
681  *
682  * When a file extent is removed file truncation, we find the
683  * corresponding implicit back refs and check the following fields:
684  *
685  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
686  *
687  * Btree extents can be referenced by:
688  *
689  * - Different subvolumes
690  *
691  * Both the implicit back refs and the full back refs for tree blocks
692  * only consist of key. The key offset for the implicit back refs is
693  * objectid of block's owner tree. The key offset for the full back refs
694  * is the first byte of parent block.
695  *
696  * When implicit back refs is used, information about the lowest key and
697  * level of the tree block are required. These information are stored in
698  * tree block info structure.
699  */
700
701 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
702 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
703                                   struct btrfs_root *root,
704                                   struct btrfs_path *path,
705                                   u64 owner, u32 extra_size)
706 {
707         struct btrfs_extent_item *item;
708         struct btrfs_extent_item_v0 *ei0;
709         struct btrfs_extent_ref_v0 *ref0;
710         struct btrfs_tree_block_info *bi;
711         struct extent_buffer *leaf;
712         struct btrfs_key key;
713         struct btrfs_key found_key;
714         u32 new_size = sizeof(*item);
715         u64 refs;
716         int ret;
717
718         leaf = path->nodes[0];
719         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
720
721         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
722         ei0 = btrfs_item_ptr(leaf, path->slots[0],
723                              struct btrfs_extent_item_v0);
724         refs = btrfs_extent_refs_v0(leaf, ei0);
725
726         if (owner == (u64)-1) {
727                 while (1) {
728                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
729                                 ret = btrfs_next_leaf(root, path);
730                                 if (ret < 0)
731                                         return ret;
732                                 BUG_ON(ret > 0);
733                                 leaf = path->nodes[0];
734                         }
735                         btrfs_item_key_to_cpu(leaf, &found_key,
736                                               path->slots[0]);
737                         BUG_ON(key.objectid != found_key.objectid);
738                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
739                                 path->slots[0]++;
740                                 continue;
741                         }
742                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
743                                               struct btrfs_extent_ref_v0);
744                         owner = btrfs_ref_objectid_v0(leaf, ref0);
745                         break;
746                 }
747         }
748         btrfs_release_path(root, path);
749
750         if (owner < BTRFS_FIRST_FREE_OBJECTID)
751                 new_size += sizeof(*bi);
752
753         new_size -= sizeof(*ei0);
754         ret = btrfs_search_slot(trans, root, &key, path,
755                                 new_size + extra_size, 1);
756         if (ret < 0)
757                 return ret;
758         BUG_ON(ret);
759
760         ret = btrfs_extend_item(trans, root, path, new_size);
761         BUG_ON(ret);
762
763         leaf = path->nodes[0];
764         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
765         btrfs_set_extent_refs(leaf, item, refs);
766         /* FIXME: get real generation */
767         btrfs_set_extent_generation(leaf, item, 0);
768         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
769                 btrfs_set_extent_flags(leaf, item,
770                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
771                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
772                 bi = (struct btrfs_tree_block_info *)(item + 1);
773                 /* FIXME: get first key of the block */
774                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
775                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
776         } else {
777                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
778         }
779         btrfs_mark_buffer_dirty(leaf);
780         return 0;
781 }
782 #endif
783
784 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
785 {
786         u32 high_crc = ~(u32)0;
787         u32 low_crc = ~(u32)0;
788         __le64 lenum;
789
790         lenum = cpu_to_le64(root_objectid);
791         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
792         lenum = cpu_to_le64(owner);
793         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
794         lenum = cpu_to_le64(offset);
795         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
796
797         return ((u64)high_crc << 31) ^ (u64)low_crc;
798 }
799
800 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
801                                      struct btrfs_extent_data_ref *ref)
802 {
803         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
804                                     btrfs_extent_data_ref_objectid(leaf, ref),
805                                     btrfs_extent_data_ref_offset(leaf, ref));
806 }
807
808 static int match_extent_data_ref(struct extent_buffer *leaf,
809                                  struct btrfs_extent_data_ref *ref,
810                                  u64 root_objectid, u64 owner, u64 offset)
811 {
812         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
813             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
814             btrfs_extent_data_ref_offset(leaf, ref) != offset)
815                 return 0;
816         return 1;
817 }
818
819 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
820                                            struct btrfs_root *root,
821                                            struct btrfs_path *path,
822                                            u64 bytenr, u64 parent,
823                                            u64 root_objectid,
824                                            u64 owner, u64 offset)
825 {
826         struct btrfs_key key;
827         struct btrfs_extent_data_ref *ref;
828         struct extent_buffer *leaf;
829         u32 nritems;
830         int ret;
831         int recow;
832         int err = -ENOENT;
833
834         key.objectid = bytenr;
835         if (parent) {
836                 key.type = BTRFS_SHARED_DATA_REF_KEY;
837                 key.offset = parent;
838         } else {
839                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
840                 key.offset = hash_extent_data_ref(root_objectid,
841                                                   owner, offset);
842         }
843 again:
844         recow = 0;
845         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
846         if (ret < 0) {
847                 err = ret;
848                 goto fail;
849         }
850
851         if (parent) {
852                 if (!ret)
853                         return 0;
854 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
855                 key.type = BTRFS_EXTENT_REF_V0_KEY;
856                 btrfs_release_path(root, path);
857                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
858                 if (ret < 0) {
859                         err = ret;
860                         goto fail;
861                 }
862                 if (!ret)
863                         return 0;
864 #endif
865                 goto fail;
866         }
867
868         leaf = path->nodes[0];
869         nritems = btrfs_header_nritems(leaf);
870         while (1) {
871                 if (path->slots[0] >= nritems) {
872                         ret = btrfs_next_leaf(root, path);
873                         if (ret < 0)
874                                 err = ret;
875                         if (ret)
876                                 goto fail;
877
878                         leaf = path->nodes[0];
879                         nritems = btrfs_header_nritems(leaf);
880                         recow = 1;
881                 }
882
883                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
884                 if (key.objectid != bytenr ||
885                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
886                         goto fail;
887
888                 ref = btrfs_item_ptr(leaf, path->slots[0],
889                                      struct btrfs_extent_data_ref);
890
891                 if (match_extent_data_ref(leaf, ref, root_objectid,
892                                           owner, offset)) {
893                         if (recow) {
894                                 btrfs_release_path(root, path);
895                                 goto again;
896                         }
897                         err = 0;
898                         break;
899                 }
900                 path->slots[0]++;
901         }
902 fail:
903         return err;
904 }
905
906 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
907                                            struct btrfs_root *root,
908                                            struct btrfs_path *path,
909                                            u64 bytenr, u64 parent,
910                                            u64 root_objectid, u64 owner,
911                                            u64 offset, int refs_to_add)
912 {
913         struct btrfs_key key;
914         struct extent_buffer *leaf;
915         u32 size;
916         u32 num_refs;
917         int ret;
918
919         key.objectid = bytenr;
920         if (parent) {
921                 key.type = BTRFS_SHARED_DATA_REF_KEY;
922                 key.offset = parent;
923                 size = sizeof(struct btrfs_shared_data_ref);
924         } else {
925                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
926                 key.offset = hash_extent_data_ref(root_objectid,
927                                                   owner, offset);
928                 size = sizeof(struct btrfs_extent_data_ref);
929         }
930
931         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
932         if (ret && ret != -EEXIST)
933                 goto fail;
934
935         leaf = path->nodes[0];
936         if (parent) {
937                 struct btrfs_shared_data_ref *ref;
938                 ref = btrfs_item_ptr(leaf, path->slots[0],
939                                      struct btrfs_shared_data_ref);
940                 if (ret == 0) {
941                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
942                 } else {
943                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
944                         num_refs += refs_to_add;
945                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
946                 }
947         } else {
948                 struct btrfs_extent_data_ref *ref;
949                 while (ret == -EEXIST) {
950                         ref = btrfs_item_ptr(leaf, path->slots[0],
951                                              struct btrfs_extent_data_ref);
952                         if (match_extent_data_ref(leaf, ref, root_objectid,
953                                                   owner, offset))
954                                 break;
955                         btrfs_release_path(root, path);
956                         key.offset++;
957                         ret = btrfs_insert_empty_item(trans, root, path, &key,
958                                                       size);
959                         if (ret && ret != -EEXIST)
960                                 goto fail;
961
962                         leaf = path->nodes[0];
963                 }
964                 ref = btrfs_item_ptr(leaf, path->slots[0],
965                                      struct btrfs_extent_data_ref);
966                 if (ret == 0) {
967                         btrfs_set_extent_data_ref_root(leaf, ref,
968                                                        root_objectid);
969                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
970                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
971                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
972                 } else {
973                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
974                         num_refs += refs_to_add;
975                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
976                 }
977         }
978         btrfs_mark_buffer_dirty(leaf);
979         ret = 0;
980 fail:
981         btrfs_release_path(root, path);
982         return ret;
983 }
984
985 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
986                                            struct btrfs_root *root,
987                                            struct btrfs_path *path,
988                                            int refs_to_drop)
989 {
990         struct btrfs_key key;
991         struct btrfs_extent_data_ref *ref1 = NULL;
992         struct btrfs_shared_data_ref *ref2 = NULL;
993         struct extent_buffer *leaf;
994         u32 num_refs = 0;
995         int ret = 0;
996
997         leaf = path->nodes[0];
998         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
999
1000         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1001                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1002                                       struct btrfs_extent_data_ref);
1003                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1004         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1005                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1006                                       struct btrfs_shared_data_ref);
1007                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1008 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1009         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1010                 struct btrfs_extent_ref_v0 *ref0;
1011                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1012                                       struct btrfs_extent_ref_v0);
1013                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1014 #endif
1015         } else {
1016                 BUG();
1017         }
1018
1019         BUG_ON(num_refs < refs_to_drop);
1020         num_refs -= refs_to_drop;
1021
1022         if (num_refs == 0) {
1023                 ret = btrfs_del_item(trans, root, path);
1024         } else {
1025                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1026                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1027                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1028                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1029 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1030                 else {
1031                         struct btrfs_extent_ref_v0 *ref0;
1032                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1033                                         struct btrfs_extent_ref_v0);
1034                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1035                 }
1036 #endif
1037                 btrfs_mark_buffer_dirty(leaf);
1038         }
1039         return ret;
1040 }
1041
1042 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
1043                                           struct btrfs_path *path,
1044                                           struct btrfs_extent_inline_ref *iref)
1045 {
1046         struct btrfs_key key;
1047         struct extent_buffer *leaf;
1048         struct btrfs_extent_data_ref *ref1;
1049         struct btrfs_shared_data_ref *ref2;
1050         u32 num_refs = 0;
1051
1052         leaf = path->nodes[0];
1053         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1054         if (iref) {
1055                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1056                     BTRFS_EXTENT_DATA_REF_KEY) {
1057                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1058                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1059                 } else {
1060                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1061                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1062                 }
1063         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1064                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1065                                       struct btrfs_extent_data_ref);
1066                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1067         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1068                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1069                                       struct btrfs_shared_data_ref);
1070                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1071 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1072         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1073                 struct btrfs_extent_ref_v0 *ref0;
1074                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1075                                       struct btrfs_extent_ref_v0);
1076                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1077 #endif
1078         } else {
1079                 WARN_ON(1);
1080         }
1081         return num_refs;
1082 }
1083
1084 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1085                                           struct btrfs_root *root,
1086                                           struct btrfs_path *path,
1087                                           u64 bytenr, u64 parent,
1088                                           u64 root_objectid)
1089 {
1090         struct btrfs_key key;
1091         int ret;
1092
1093         key.objectid = bytenr;
1094         if (parent) {
1095                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1096                 key.offset = parent;
1097         } else {
1098                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1099                 key.offset = root_objectid;
1100         }
1101
1102         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1103         if (ret > 0)
1104                 ret = -ENOENT;
1105 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1106         if (ret == -ENOENT && parent) {
1107                 btrfs_release_path(root, path);
1108                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1109                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1110                 if (ret > 0)
1111                         ret = -ENOENT;
1112         }
1113 #endif
1114         return ret;
1115 }
1116
1117 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1118                                           struct btrfs_root *root,
1119                                           struct btrfs_path *path,
1120                                           u64 bytenr, u64 parent,
1121                                           u64 root_objectid)
1122 {
1123         struct btrfs_key key;
1124         int ret;
1125
1126         key.objectid = bytenr;
1127         if (parent) {
1128                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1129                 key.offset = parent;
1130         } else {
1131                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1132                 key.offset = root_objectid;
1133         }
1134
1135         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1136         btrfs_release_path(root, path);
1137         return ret;
1138 }
1139
1140 static inline int extent_ref_type(u64 parent, u64 owner)
1141 {
1142         int type;
1143         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1144                 if (parent > 0)
1145                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1146                 else
1147                         type = BTRFS_TREE_BLOCK_REF_KEY;
1148         } else {
1149                 if (parent > 0)
1150                         type = BTRFS_SHARED_DATA_REF_KEY;
1151                 else
1152                         type = BTRFS_EXTENT_DATA_REF_KEY;
1153         }
1154         return type;
1155 }
1156
1157 static int find_next_key(struct btrfs_path *path, int level,
1158                          struct btrfs_key *key)
1159
1160 {
1161         for (; level < BTRFS_MAX_LEVEL; level++) {
1162                 if (!path->nodes[level])
1163                         break;
1164                 if (path->slots[level] + 1 >=
1165                     btrfs_header_nritems(path->nodes[level]))
1166                         continue;
1167                 if (level == 0)
1168                         btrfs_item_key_to_cpu(path->nodes[level], key,
1169                                               path->slots[level] + 1);
1170                 else
1171                         btrfs_node_key_to_cpu(path->nodes[level], key,
1172                                               path->slots[level] + 1);
1173                 return 0;
1174         }
1175         return 1;
1176 }
1177
1178 /*
1179  * look for inline back ref. if back ref is found, *ref_ret is set
1180  * to the address of inline back ref, and 0 is returned.
1181  *
1182  * if back ref isn't found, *ref_ret is set to the address where it
1183  * should be inserted, and -ENOENT is returned.
1184  *
1185  * if insert is true and there are too many inline back refs, the path
1186  * points to the extent item, and -EAGAIN is returned.
1187  *
1188  * NOTE: inline back refs are ordered in the same way that back ref
1189  *       items in the tree are ordered.
1190  */
1191 static noinline_for_stack
1192 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1193                                  struct btrfs_root *root,
1194                                  struct btrfs_path *path,
1195                                  struct btrfs_extent_inline_ref **ref_ret,
1196                                  u64 bytenr, u64 num_bytes,
1197                                  u64 parent, u64 root_objectid,
1198                                  u64 owner, u64 offset, int insert)
1199 {
1200         struct btrfs_key key;
1201         struct extent_buffer *leaf;
1202         struct btrfs_extent_item *ei;
1203         struct btrfs_extent_inline_ref *iref;
1204         u64 flags;
1205         u64 item_size;
1206         unsigned long ptr;
1207         unsigned long end;
1208         int extra_size;
1209         int type;
1210         int want;
1211         int ret;
1212         int err = 0;
1213
1214         key.objectid = bytenr;
1215         key.type = BTRFS_EXTENT_ITEM_KEY;
1216         key.offset = num_bytes;
1217
1218         want = extent_ref_type(parent, owner);
1219         if (insert) {
1220                 extra_size = btrfs_extent_inline_ref_size(want);
1221                 path->keep_locks = 1;
1222         } else
1223                 extra_size = -1;
1224         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1225         if (ret < 0) {
1226                 err = ret;
1227                 goto out;
1228         }
1229         BUG_ON(ret);
1230
1231         leaf = path->nodes[0];
1232         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1233 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1234         if (item_size < sizeof(*ei)) {
1235                 if (!insert) {
1236                         err = -ENOENT;
1237                         goto out;
1238                 }
1239                 ret = convert_extent_item_v0(trans, root, path, owner,
1240                                              extra_size);
1241                 if (ret < 0) {
1242                         err = ret;
1243                         goto out;
1244                 }
1245                 leaf = path->nodes[0];
1246                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1247         }
1248 #endif
1249         BUG_ON(item_size < sizeof(*ei));
1250
1251         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1252         flags = btrfs_extent_flags(leaf, ei);
1253
1254         ptr = (unsigned long)(ei + 1);
1255         end = (unsigned long)ei + item_size;
1256
1257         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1258                 ptr += sizeof(struct btrfs_tree_block_info);
1259                 BUG_ON(ptr > end);
1260         } else {
1261                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
1262         }
1263
1264         err = -ENOENT;
1265         while (1) {
1266                 if (ptr >= end) {
1267                         WARN_ON(ptr > end);
1268                         break;
1269                 }
1270                 iref = (struct btrfs_extent_inline_ref *)ptr;
1271                 type = btrfs_extent_inline_ref_type(leaf, iref);
1272                 if (want < type)
1273                         break;
1274                 if (want > type) {
1275                         ptr += btrfs_extent_inline_ref_size(type);
1276                         continue;
1277                 }
1278
1279                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1280                         struct btrfs_extent_data_ref *dref;
1281                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1282                         if (match_extent_data_ref(leaf, dref, root_objectid,
1283                                                   owner, offset)) {
1284                                 err = 0;
1285                                 break;
1286                         }
1287                         if (hash_extent_data_ref_item(leaf, dref) <
1288                             hash_extent_data_ref(root_objectid, owner, offset))
1289                                 break;
1290                 } else {
1291                         u64 ref_offset;
1292                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1293                         if (parent > 0) {
1294                                 if (parent == ref_offset) {
1295                                         err = 0;
1296                                         break;
1297                                 }
1298                                 if (ref_offset < parent)
1299                                         break;
1300                         } else {
1301                                 if (root_objectid == ref_offset) {
1302                                         err = 0;
1303                                         break;
1304                                 }
1305                                 if (ref_offset < root_objectid)
1306                                         break;
1307                         }
1308                 }
1309                 ptr += btrfs_extent_inline_ref_size(type);
1310         }
1311         if (err == -ENOENT && insert) {
1312                 if (item_size + extra_size >=
1313                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1314                         err = -EAGAIN;
1315                         goto out;
1316                 }
1317                 /*
1318                  * To add new inline back ref, we have to make sure
1319                  * there is no corresponding back ref item.
1320                  * For simplicity, we just do not add new inline back
1321                  * ref if there is any kind of item for this block
1322                  */
1323                 if (find_next_key(path, 0, &key) == 0 &&
1324                     key.objectid == bytenr &&
1325                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1326                         err = -EAGAIN;
1327                         goto out;
1328                 }
1329         }
1330         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1331 out:
1332         if (insert) {
1333                 path->keep_locks = 0;
1334                 btrfs_unlock_up_safe(path, 1);
1335         }
1336         return err;
1337 }
1338
1339 /*
1340  * helper to add new inline back ref
1341  */
1342 static noinline_for_stack
1343 int setup_inline_extent_backref(struct btrfs_trans_handle *trans,
1344                                 struct btrfs_root *root,
1345                                 struct btrfs_path *path,
1346                                 struct btrfs_extent_inline_ref *iref,
1347                                 u64 parent, u64 root_objectid,
1348                                 u64 owner, u64 offset, int refs_to_add,
1349                                 struct btrfs_delayed_extent_op *extent_op)
1350 {
1351         struct extent_buffer *leaf;
1352         struct btrfs_extent_item *ei;
1353         unsigned long ptr;
1354         unsigned long end;
1355         unsigned long item_offset;
1356         u64 refs;
1357         int size;
1358         int type;
1359         int ret;
1360
1361         leaf = path->nodes[0];
1362         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1363         item_offset = (unsigned long)iref - (unsigned long)ei;
1364
1365         type = extent_ref_type(parent, owner);
1366         size = btrfs_extent_inline_ref_size(type);
1367
1368         ret = btrfs_extend_item(trans, root, path, size);
1369         BUG_ON(ret);
1370
1371         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1372         refs = btrfs_extent_refs(leaf, ei);
1373         refs += refs_to_add;
1374         btrfs_set_extent_refs(leaf, ei, refs);
1375         if (extent_op)
1376                 __run_delayed_extent_op(extent_op, leaf, ei);
1377
1378         ptr = (unsigned long)ei + item_offset;
1379         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1380         if (ptr < end - size)
1381                 memmove_extent_buffer(leaf, ptr + size, ptr,
1382                                       end - size - ptr);
1383
1384         iref = (struct btrfs_extent_inline_ref *)ptr;
1385         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1386         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1387                 struct btrfs_extent_data_ref *dref;
1388                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1389                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1390                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1391                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1392                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1393         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1394                 struct btrfs_shared_data_ref *sref;
1395                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1396                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1397                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1398         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1399                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1400         } else {
1401                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1402         }
1403         btrfs_mark_buffer_dirty(leaf);
1404         return 0;
1405 }
1406
1407 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1408                                  struct btrfs_root *root,
1409                                  struct btrfs_path *path,
1410                                  struct btrfs_extent_inline_ref **ref_ret,
1411                                  u64 bytenr, u64 num_bytes, u64 parent,
1412                                  u64 root_objectid, u64 owner, u64 offset)
1413 {
1414         int ret;
1415
1416         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1417                                            bytenr, num_bytes, parent,
1418                                            root_objectid, owner, offset, 0);
1419         if (ret != -ENOENT)
1420                 return ret;
1421
1422         btrfs_release_path(root, path);
1423         *ref_ret = NULL;
1424
1425         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1426                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1427                                             root_objectid);
1428         } else {
1429                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1430                                              root_objectid, owner, offset);
1431         }
1432         return ret;
1433 }
1434
1435 /*
1436  * helper to update/remove inline back ref
1437  */
1438 static noinline_for_stack
1439 int update_inline_extent_backref(struct btrfs_trans_handle *trans,
1440                                  struct btrfs_root *root,
1441                                  struct btrfs_path *path,
1442                                  struct btrfs_extent_inline_ref *iref,
1443                                  int refs_to_mod,
1444                                  struct btrfs_delayed_extent_op *extent_op)
1445 {
1446         struct extent_buffer *leaf;
1447         struct btrfs_extent_item *ei;
1448         struct btrfs_extent_data_ref *dref = NULL;
1449         struct btrfs_shared_data_ref *sref = NULL;
1450         unsigned long ptr;
1451         unsigned long end;
1452         u32 item_size;
1453         int size;
1454         int type;
1455         int ret;
1456         u64 refs;
1457
1458         leaf = path->nodes[0];
1459         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1460         refs = btrfs_extent_refs(leaf, ei);
1461         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1462         refs += refs_to_mod;
1463         btrfs_set_extent_refs(leaf, ei, refs);
1464         if (extent_op)
1465                 __run_delayed_extent_op(extent_op, leaf, ei);
1466
1467         type = btrfs_extent_inline_ref_type(leaf, iref);
1468
1469         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1470                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1471                 refs = btrfs_extent_data_ref_count(leaf, dref);
1472         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1473                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1474                 refs = btrfs_shared_data_ref_count(leaf, sref);
1475         } else {
1476                 refs = 1;
1477                 BUG_ON(refs_to_mod != -1);
1478         }
1479
1480         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1481         refs += refs_to_mod;
1482
1483         if (refs > 0) {
1484                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1485                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1486                 else
1487                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1488         } else {
1489                 size =  btrfs_extent_inline_ref_size(type);
1490                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1491                 ptr = (unsigned long)iref;
1492                 end = (unsigned long)ei + item_size;
1493                 if (ptr + size < end)
1494                         memmove_extent_buffer(leaf, ptr, ptr + size,
1495                                               end - ptr - size);
1496                 item_size -= size;
1497                 ret = btrfs_truncate_item(trans, root, path, item_size, 1);
1498                 BUG_ON(ret);
1499         }
1500         btrfs_mark_buffer_dirty(leaf);
1501         return 0;
1502 }
1503
1504 static noinline_for_stack
1505 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1506                                  struct btrfs_root *root,
1507                                  struct btrfs_path *path,
1508                                  u64 bytenr, u64 num_bytes, u64 parent,
1509                                  u64 root_objectid, u64 owner,
1510                                  u64 offset, int refs_to_add,
1511                                  struct btrfs_delayed_extent_op *extent_op)
1512 {
1513         struct btrfs_extent_inline_ref *iref;
1514         int ret;
1515
1516         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1517                                            bytenr, num_bytes, parent,
1518                                            root_objectid, owner, offset, 1);
1519         if (ret == 0) {
1520                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1521                 ret = update_inline_extent_backref(trans, root, path, iref,
1522                                                    refs_to_add, extent_op);
1523         } else if (ret == -ENOENT) {
1524                 ret = setup_inline_extent_backref(trans, root, path, iref,
1525                                                   parent, root_objectid,
1526                                                   owner, offset, refs_to_add,
1527                                                   extent_op);
1528         }
1529         return ret;
1530 }
1531
1532 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1533                                  struct btrfs_root *root,
1534                                  struct btrfs_path *path,
1535                                  u64 bytenr, u64 parent, u64 root_objectid,
1536                                  u64 owner, u64 offset, int refs_to_add)
1537 {
1538         int ret;
1539         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1540                 BUG_ON(refs_to_add != 1);
1541                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1542                                             parent, root_objectid);
1543         } else {
1544                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1545                                              parent, root_objectid,
1546                                              owner, offset, refs_to_add);
1547         }
1548         return ret;
1549 }
1550
1551 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1552                                  struct btrfs_root *root,
1553                                  struct btrfs_path *path,
1554                                  struct btrfs_extent_inline_ref *iref,
1555                                  int refs_to_drop, int is_data)
1556 {
1557         int ret;
1558
1559         BUG_ON(!is_data && refs_to_drop != 1);
1560         if (iref) {
1561                 ret = update_inline_extent_backref(trans, root, path, iref,
1562                                                    -refs_to_drop, NULL);
1563         } else if (is_data) {
1564                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1565         } else {
1566                 ret = btrfs_del_item(trans, root, path);
1567         }
1568         return ret;
1569 }
1570
1571 static void btrfs_issue_discard(struct block_device *bdev,
1572                                 u64 start, u64 len)
1573 {
1574         blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_KERNEL,
1575                              DISCARD_FL_BARRIER);
1576 }
1577
1578 static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1579                                 u64 num_bytes)
1580 {
1581         int ret;
1582         u64 map_length = num_bytes;
1583         struct btrfs_multi_bio *multi = NULL;
1584
1585         if (!btrfs_test_opt(root, DISCARD))
1586                 return 0;
1587
1588         /* Tell the block device(s) that the sectors can be discarded */
1589         ret = btrfs_map_block(&root->fs_info->mapping_tree, READ,
1590                               bytenr, &map_length, &multi, 0);
1591         if (!ret) {
1592                 struct btrfs_bio_stripe *stripe = multi->stripes;
1593                 int i;
1594
1595                 if (map_length > num_bytes)
1596                         map_length = num_bytes;
1597
1598                 for (i = 0; i < multi->num_stripes; i++, stripe++) {
1599                         btrfs_issue_discard(stripe->dev->bdev,
1600                                             stripe->physical,
1601                                             map_length);
1602                 }
1603                 kfree(multi);
1604         }
1605
1606         return ret;
1607 }
1608
1609 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1610                          struct btrfs_root *root,
1611                          u64 bytenr, u64 num_bytes, u64 parent,
1612                          u64 root_objectid, u64 owner, u64 offset)
1613 {
1614         int ret;
1615         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
1616                root_objectid == BTRFS_TREE_LOG_OBJECTID);
1617
1618         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1619                 ret = btrfs_add_delayed_tree_ref(trans, bytenr, num_bytes,
1620                                         parent, root_objectid, (int)owner,
1621                                         BTRFS_ADD_DELAYED_REF, NULL);
1622         } else {
1623                 ret = btrfs_add_delayed_data_ref(trans, bytenr, num_bytes,
1624                                         parent, root_objectid, owner, offset,
1625                                         BTRFS_ADD_DELAYED_REF, NULL);
1626         }
1627         return ret;
1628 }
1629
1630 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1631                                   struct btrfs_root *root,
1632                                   u64 bytenr, u64 num_bytes,
1633                                   u64 parent, u64 root_objectid,
1634                                   u64 owner, u64 offset, int refs_to_add,
1635                                   struct btrfs_delayed_extent_op *extent_op)
1636 {
1637         struct btrfs_path *path;
1638         struct extent_buffer *leaf;
1639         struct btrfs_extent_item *item;
1640         u64 refs;
1641         int ret;
1642         int err = 0;
1643
1644         path = btrfs_alloc_path();
1645         if (!path)
1646                 return -ENOMEM;
1647
1648         path->reada = 1;
1649         path->leave_spinning = 1;
1650         /* this will setup the path even if it fails to insert the back ref */
1651         ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
1652                                            path, bytenr, num_bytes, parent,
1653                                            root_objectid, owner, offset,
1654                                            refs_to_add, extent_op);
1655         if (ret == 0)
1656                 goto out;
1657
1658         if (ret != -EAGAIN) {
1659                 err = ret;
1660                 goto out;
1661         }
1662
1663         leaf = path->nodes[0];
1664         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1665         refs = btrfs_extent_refs(leaf, item);
1666         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
1667         if (extent_op)
1668                 __run_delayed_extent_op(extent_op, leaf, item);
1669
1670         btrfs_mark_buffer_dirty(leaf);
1671         btrfs_release_path(root->fs_info->extent_root, path);
1672
1673         path->reada = 1;
1674         path->leave_spinning = 1;
1675
1676         /* now insert the actual backref */
1677         ret = insert_extent_backref(trans, root->fs_info->extent_root,
1678                                     path, bytenr, parent, root_objectid,
1679                                     owner, offset, refs_to_add);
1680         BUG_ON(ret);
1681 out:
1682         btrfs_free_path(path);
1683         return err;
1684 }
1685
1686 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
1687                                 struct btrfs_root *root,
1688                                 struct btrfs_delayed_ref_node *node,
1689                                 struct btrfs_delayed_extent_op *extent_op,
1690                                 int insert_reserved)
1691 {
1692         int ret = 0;
1693         struct btrfs_delayed_data_ref *ref;
1694         struct btrfs_key ins;
1695         u64 parent = 0;
1696         u64 ref_root = 0;
1697         u64 flags = 0;
1698
1699         ins.objectid = node->bytenr;
1700         ins.offset = node->num_bytes;
1701         ins.type = BTRFS_EXTENT_ITEM_KEY;
1702
1703         ref = btrfs_delayed_node_to_data_ref(node);
1704         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
1705                 parent = ref->parent;
1706         else
1707                 ref_root = ref->root;
1708
1709         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1710                 if (extent_op) {
1711                         BUG_ON(extent_op->update_key);
1712                         flags |= extent_op->flags_to_set;
1713                 }
1714                 ret = alloc_reserved_file_extent(trans, root,
1715                                                  parent, ref_root, flags,
1716                                                  ref->objectid, ref->offset,
1717                                                  &ins, node->ref_mod);
1718         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
1719                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
1720                                              node->num_bytes, parent,
1721                                              ref_root, ref->objectid,
1722                                              ref->offset, node->ref_mod,
1723                                              extent_op);
1724         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
1725                 ret = __btrfs_free_extent(trans, root, node->bytenr,
1726                                           node->num_bytes, parent,
1727                                           ref_root, ref->objectid,
1728                                           ref->offset, node->ref_mod,
1729                                           extent_op);
1730         } else {
1731                 BUG();
1732         }
1733         return ret;
1734 }
1735
1736 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
1737                                     struct extent_buffer *leaf,
1738                                     struct btrfs_extent_item *ei)
1739 {
1740         u64 flags = btrfs_extent_flags(leaf, ei);
1741         if (extent_op->update_flags) {
1742                 flags |= extent_op->flags_to_set;
1743                 btrfs_set_extent_flags(leaf, ei, flags);
1744         }
1745
1746         if (extent_op->update_key) {
1747                 struct btrfs_tree_block_info *bi;
1748                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
1749                 bi = (struct btrfs_tree_block_info *)(ei + 1);
1750                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
1751         }
1752 }
1753
1754 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
1755                                  struct btrfs_root *root,
1756                                  struct btrfs_delayed_ref_node *node,
1757                                  struct btrfs_delayed_extent_op *extent_op)
1758 {
1759         struct btrfs_key key;
1760         struct btrfs_path *path;
1761         struct btrfs_extent_item *ei;
1762         struct extent_buffer *leaf;
1763         u32 item_size;
1764         int ret;
1765         int err = 0;
1766
1767         path = btrfs_alloc_path();
1768         if (!path)
1769                 return -ENOMEM;
1770
1771         key.objectid = node->bytenr;
1772         key.type = BTRFS_EXTENT_ITEM_KEY;
1773         key.offset = node->num_bytes;
1774
1775         path->reada = 1;
1776         path->leave_spinning = 1;
1777         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
1778                                 path, 0, 1);
1779         if (ret < 0) {
1780                 err = ret;
1781                 goto out;
1782         }
1783         if (ret > 0) {
1784                 err = -EIO;
1785                 goto out;
1786         }
1787
1788         leaf = path->nodes[0];
1789         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1790 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1791         if (item_size < sizeof(*ei)) {
1792                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
1793                                              path, (u64)-1, 0);
1794                 if (ret < 0) {
1795                         err = ret;
1796                         goto out;
1797                 }
1798                 leaf = path->nodes[0];
1799                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1800         }
1801 #endif
1802         BUG_ON(item_size < sizeof(*ei));
1803         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1804         __run_delayed_extent_op(extent_op, leaf, ei);
1805
1806         btrfs_mark_buffer_dirty(leaf);
1807 out:
1808         btrfs_free_path(path);
1809         return err;
1810 }
1811
1812 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
1813                                 struct btrfs_root *root,
1814                                 struct btrfs_delayed_ref_node *node,
1815                                 struct btrfs_delayed_extent_op *extent_op,
1816                                 int insert_reserved)
1817 {
1818         int ret = 0;
1819         struct btrfs_delayed_tree_ref *ref;
1820         struct btrfs_key ins;
1821         u64 parent = 0;
1822         u64 ref_root = 0;
1823
1824         ins.objectid = node->bytenr;
1825         ins.offset = node->num_bytes;
1826         ins.type = BTRFS_EXTENT_ITEM_KEY;
1827
1828         ref = btrfs_delayed_node_to_tree_ref(node);
1829         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
1830                 parent = ref->parent;
1831         else
1832                 ref_root = ref->root;
1833
1834         BUG_ON(node->ref_mod != 1);
1835         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1836                 BUG_ON(!extent_op || !extent_op->update_flags ||
1837                        !extent_op->update_key);
1838                 ret = alloc_reserved_tree_block(trans, root,
1839                                                 parent, ref_root,
1840                                                 extent_op->flags_to_set,
1841                                                 &extent_op->key,
1842                                                 ref->level, &ins);
1843         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
1844                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
1845                                              node->num_bytes, parent, ref_root,
1846                                              ref->level, 0, 1, extent_op);
1847         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
1848                 ret = __btrfs_free_extent(trans, root, node->bytenr,
1849                                           node->num_bytes, parent, ref_root,
1850                                           ref->level, 0, 1, extent_op);
1851         } else {
1852                 BUG();
1853         }
1854         return ret;
1855 }
1856
1857
1858 /* helper function to actually process a single delayed ref entry */
1859 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
1860                                struct btrfs_root *root,
1861                                struct btrfs_delayed_ref_node *node,
1862                                struct btrfs_delayed_extent_op *extent_op,
1863                                int insert_reserved)
1864 {
1865         int ret;
1866         if (btrfs_delayed_ref_is_head(node)) {
1867                 struct btrfs_delayed_ref_head *head;
1868                 /*
1869                  * we've hit the end of the chain and we were supposed
1870                  * to insert this extent into the tree.  But, it got
1871                  * deleted before we ever needed to insert it, so all
1872                  * we have to do is clean up the accounting
1873                  */
1874                 BUG_ON(extent_op);
1875                 head = btrfs_delayed_node_to_head(node);
1876                 if (insert_reserved) {
1877                         int mark_free = 0;
1878                         struct extent_buffer *must_clean = NULL;
1879
1880                         ret = pin_down_bytes(trans, root, NULL,
1881                                              node->bytenr, node->num_bytes,
1882                                              head->is_data, 1, &must_clean);
1883                         if (ret > 0)
1884                                 mark_free = 1;
1885
1886                         if (must_clean) {
1887                                 clean_tree_block(NULL, root, must_clean);
1888                                 btrfs_tree_unlock(must_clean);
1889                                 free_extent_buffer(must_clean);
1890                         }
1891                         if (head->is_data) {
1892                                 ret = btrfs_del_csums(trans, root,
1893                                                       node->bytenr,
1894                                                       node->num_bytes);
1895                                 BUG_ON(ret);
1896                         }
1897                         if (mark_free) {
1898                                 ret = btrfs_free_reserved_extent(root,
1899                                                         node->bytenr,
1900                                                         node->num_bytes);
1901                                 BUG_ON(ret);
1902                         }
1903                 }
1904                 mutex_unlock(&head->mutex);
1905                 return 0;
1906         }
1907
1908         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
1909             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
1910                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
1911                                            insert_reserved);
1912         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
1913                  node->type == BTRFS_SHARED_DATA_REF_KEY)
1914                 ret = run_delayed_data_ref(trans, root, node, extent_op,
1915                                            insert_reserved);
1916         else
1917                 BUG();
1918         return ret;
1919 }
1920
1921 static noinline struct btrfs_delayed_ref_node *
1922 select_delayed_ref(struct btrfs_delayed_ref_head *head)
1923 {
1924         struct rb_node *node;
1925         struct btrfs_delayed_ref_node *ref;
1926         int action = BTRFS_ADD_DELAYED_REF;
1927 again:
1928         /*
1929          * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
1930          * this prevents ref count from going down to zero when
1931          * there still are pending delayed ref.
1932          */
1933         node = rb_prev(&head->node.rb_node);
1934         while (1) {
1935                 if (!node)
1936                         break;
1937                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
1938                                 rb_node);
1939                 if (ref->bytenr != head->node.bytenr)
1940                         break;
1941                 if (ref->action == action)
1942                         return ref;
1943                 node = rb_prev(node);
1944         }
1945         if (action == BTRFS_ADD_DELAYED_REF) {
1946                 action = BTRFS_DROP_DELAYED_REF;
1947                 goto again;
1948         }
1949         return NULL;
1950 }
1951
1952 static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
1953                                        struct btrfs_root *root,
1954                                        struct list_head *cluster)
1955 {
1956         struct btrfs_delayed_ref_root *delayed_refs;
1957         struct btrfs_delayed_ref_node *ref;
1958         struct btrfs_delayed_ref_head *locked_ref = NULL;
1959         struct btrfs_delayed_extent_op *extent_op;
1960         int ret;
1961         int count = 0;
1962         int must_insert_reserved = 0;
1963
1964         delayed_refs = &trans->transaction->delayed_refs;
1965         while (1) {
1966                 if (!locked_ref) {
1967                         /* pick a new head ref from the cluster list */
1968                         if (list_empty(cluster))
1969                                 break;
1970
1971                         locked_ref = list_entry(cluster->next,
1972                                      struct btrfs_delayed_ref_head, cluster);
1973
1974                         /* grab the lock that says we are going to process
1975                          * all the refs for this head */
1976                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
1977
1978                         /*
1979                          * we may have dropped the spin lock to get the head
1980                          * mutex lock, and that might have given someone else
1981                          * time to free the head.  If that's true, it has been
1982                          * removed from our list and we can move on.
1983                          */
1984                         if (ret == -EAGAIN) {
1985                                 locked_ref = NULL;
1986                                 count++;
1987                                 continue;
1988                         }
1989                 }
1990
1991                 /*
1992                  * record the must insert reserved flag before we
1993                  * drop the spin lock.
1994                  */
1995                 must_insert_reserved = locked_ref->must_insert_reserved;
1996                 locked_ref->must_insert_reserved = 0;
1997
1998                 extent_op = locked_ref->extent_op;
1999                 locked_ref->extent_op = NULL;
2000
2001                 /*
2002                  * locked_ref is the head node, so we have to go one
2003                  * node back for any delayed ref updates
2004                  */
2005                 ref = select_delayed_ref(locked_ref);
2006                 if (!ref) {
2007                         /* All delayed refs have been processed, Go ahead
2008                          * and send the head node to run_one_delayed_ref,
2009                          * so that any accounting fixes can happen
2010                          */
2011                         ref = &locked_ref->node;
2012
2013                         if (extent_op && must_insert_reserved) {
2014                                 kfree(extent_op);
2015                                 extent_op = NULL;
2016                         }
2017
2018                         if (extent_op) {
2019                                 spin_unlock(&delayed_refs->lock);
2020
2021                                 ret = run_delayed_extent_op(trans, root,
2022                                                             ref, extent_op);
2023                                 BUG_ON(ret);
2024                                 kfree(extent_op);
2025
2026                                 cond_resched();
2027                                 spin_lock(&delayed_refs->lock);
2028                                 continue;
2029                         }
2030
2031                         list_del_init(&locked_ref->cluster);
2032                         locked_ref = NULL;
2033                 }
2034
2035                 ref->in_tree = 0;
2036                 rb_erase(&ref->rb_node, &delayed_refs->root);
2037                 delayed_refs->num_entries--;
2038
2039                 spin_unlock(&delayed_refs->lock);
2040
2041                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2042                                           must_insert_reserved);
2043                 BUG_ON(ret);
2044
2045                 btrfs_put_delayed_ref(ref);
2046                 kfree(extent_op);
2047                 count++;
2048
2049                 cond_resched();
2050                 spin_lock(&delayed_refs->lock);
2051         }
2052         return count;
2053 }
2054
2055 /*
2056  * this starts processing the delayed reference count updates and
2057  * extent insertions we have queued up so far.  count can be
2058  * 0, which means to process everything in the tree at the start
2059  * of the run (but not newly added entries), or it can be some target
2060  * number you'd like to process.
2061  */
2062 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2063                            struct btrfs_root *root, unsigned long count)
2064 {
2065         struct rb_node *node;
2066         struct btrfs_delayed_ref_root *delayed_refs;
2067         struct btrfs_delayed_ref_node *ref;
2068         struct list_head cluster;
2069         int ret;
2070         int run_all = count == (unsigned long)-1;
2071         int run_most = 0;
2072
2073         if (root == root->fs_info->extent_root)
2074                 root = root->fs_info->tree_root;
2075
2076         delayed_refs = &trans->transaction->delayed_refs;
2077         INIT_LIST_HEAD(&cluster);
2078 again:
2079         spin_lock(&delayed_refs->lock);
2080         if (count == 0) {
2081                 count = delayed_refs->num_entries * 2;
2082                 run_most = 1;
2083         }
2084         while (1) {
2085                 if (!(run_all || run_most) &&
2086                     delayed_refs->num_heads_ready < 64)
2087                         break;
2088
2089                 /*
2090                  * go find something we can process in the rbtree.  We start at
2091                  * the beginning of the tree, and then build a cluster
2092                  * of refs to process starting at the first one we are able to
2093                  * lock
2094                  */
2095                 ret = btrfs_find_ref_cluster(trans, &cluster,
2096                                              delayed_refs->run_delayed_start);
2097                 if (ret)
2098                         break;
2099
2100                 ret = run_clustered_refs(trans, root, &cluster);
2101                 BUG_ON(ret < 0);
2102
2103                 count -= min_t(unsigned long, ret, count);
2104
2105                 if (count == 0)
2106                         break;
2107         }
2108
2109         if (run_all) {
2110                 node = rb_first(&delayed_refs->root);
2111                 if (!node)
2112                         goto out;
2113                 count = (unsigned long)-1;
2114
2115                 while (node) {
2116                         ref = rb_entry(node, struct btrfs_delayed_ref_node,
2117                                        rb_node);
2118                         if (btrfs_delayed_ref_is_head(ref)) {
2119                                 struct btrfs_delayed_ref_head *head;
2120
2121                                 head = btrfs_delayed_node_to_head(ref);
2122                                 atomic_inc(&ref->refs);
2123
2124                                 spin_unlock(&delayed_refs->lock);
2125                                 mutex_lock(&head->mutex);
2126                                 mutex_unlock(&head->mutex);
2127
2128                                 btrfs_put_delayed_ref(ref);
2129                                 cond_resched();
2130                                 goto again;
2131                         }
2132                         node = rb_next(node);
2133                 }
2134                 spin_unlock(&delayed_refs->lock);
2135                 schedule_timeout(1);
2136                 goto again;
2137         }
2138 out:
2139         spin_unlock(&delayed_refs->lock);
2140         return 0;
2141 }
2142
2143 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2144                                 struct btrfs_root *root,
2145                                 u64 bytenr, u64 num_bytes, u64 flags,
2146                                 int is_data)
2147 {
2148         struct btrfs_delayed_extent_op *extent_op;
2149         int ret;
2150
2151         extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2152         if (!extent_op)
2153                 return -ENOMEM;
2154
2155         extent_op->flags_to_set = flags;
2156         extent_op->update_flags = 1;
2157         extent_op->update_key = 0;
2158         extent_op->is_data = is_data ? 1 : 0;
2159
2160         ret = btrfs_add_delayed_extent_op(trans, bytenr, num_bytes, extent_op);
2161         if (ret)
2162                 kfree(extent_op);
2163         return ret;
2164 }
2165
2166 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2167                                       struct btrfs_root *root,
2168                                       struct btrfs_path *path,
2169                                       u64 objectid, u64 offset, u64 bytenr)
2170 {
2171         struct btrfs_delayed_ref_head *head;
2172         struct btrfs_delayed_ref_node *ref;
2173         struct btrfs_delayed_data_ref *data_ref;
2174         struct btrfs_delayed_ref_root *delayed_refs;
2175         struct rb_node *node;
2176         int ret = 0;
2177
2178         ret = -ENOENT;
2179         delayed_refs = &trans->transaction->delayed_refs;
2180         spin_lock(&delayed_refs->lock);
2181         head = btrfs_find_delayed_ref_head(trans, bytenr);
2182         if (!head)
2183                 goto out;
2184
2185         if (!mutex_trylock(&head->mutex)) {
2186                 atomic_inc(&head->node.refs);
2187                 spin_unlock(&delayed_refs->lock);
2188
2189                 btrfs_release_path(root->fs_info->extent_root, path);
2190
2191                 mutex_lock(&head->mutex);
2192                 mutex_unlock(&head->mutex);
2193                 btrfs_put_delayed_ref(&head->node);
2194                 return -EAGAIN;
2195         }
2196
2197         node = rb_prev(&head->node.rb_node);
2198         if (!node)
2199                 goto out_unlock;
2200
2201         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2202
2203         if (ref->bytenr != bytenr)
2204                 goto out_unlock;
2205
2206         ret = 1;
2207         if (ref->type != BTRFS_EXTENT_DATA_REF_KEY)
2208                 goto out_unlock;
2209
2210         data_ref = btrfs_delayed_node_to_data_ref(ref);
2211
2212         node = rb_prev(node);
2213         if (node) {
2214                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2215                 if (ref->bytenr == bytenr)
2216                         goto out_unlock;
2217         }
2218
2219         if (data_ref->root != root->root_key.objectid ||
2220             data_ref->objectid != objectid || data_ref->offset != offset)
2221                 goto out_unlock;
2222
2223         ret = 0;
2224 out_unlock:
2225         mutex_unlock(&head->mutex);
2226 out:
2227         spin_unlock(&delayed_refs->lock);
2228         return ret;
2229 }
2230
2231 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2232                                         struct btrfs_root *root,
2233                                         struct btrfs_path *path,
2234                                         u64 objectid, u64 offset, u64 bytenr)
2235 {
2236         struct btrfs_root *extent_root = root->fs_info->extent_root;
2237         struct extent_buffer *leaf;
2238         struct btrfs_extent_data_ref *ref;
2239         struct btrfs_extent_inline_ref *iref;
2240         struct btrfs_extent_item *ei;
2241         struct btrfs_key key;
2242         u32 item_size;
2243         int ret;
2244
2245         key.objectid = bytenr;
2246         key.offset = (u64)-1;
2247         key.type = BTRFS_EXTENT_ITEM_KEY;
2248
2249         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2250         if (ret < 0)
2251                 goto out;
2252         BUG_ON(ret == 0);
2253
2254         ret = -ENOENT;
2255         if (path->slots[0] == 0)
2256                 goto out;
2257
2258         path->slots[0]--;
2259         leaf = path->nodes[0];
2260         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2261
2262         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2263                 goto out;
2264
2265         ret = 1;
2266         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2267 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2268         if (item_size < sizeof(*ei)) {
2269                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2270                 goto out;
2271         }
2272 #endif
2273         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2274
2275         if (item_size != sizeof(*ei) +
2276             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2277                 goto out;
2278
2279         if (btrfs_extent_generation(leaf, ei) <=
2280             btrfs_root_last_snapshot(&root->root_item))
2281                 goto out;
2282
2283         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2284         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2285             BTRFS_EXTENT_DATA_REF_KEY)
2286                 goto out;
2287
2288         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2289         if (btrfs_extent_refs(leaf, ei) !=
2290             btrfs_extent_data_ref_count(leaf, ref) ||
2291             btrfs_extent_data_ref_root(leaf, ref) !=
2292             root->root_key.objectid ||
2293             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2294             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2295                 goto out;
2296
2297         ret = 0;
2298 out:
2299         return ret;
2300 }
2301
2302 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
2303                           struct btrfs_root *root,
2304                           u64 objectid, u64 offset, u64 bytenr)
2305 {
2306         struct btrfs_path *path;
2307         int ret;
2308         int ret2;
2309
2310         path = btrfs_alloc_path();
2311         if (!path)
2312                 return -ENOENT;
2313
2314         do {
2315                 ret = check_committed_ref(trans, root, path, objectid,
2316                                           offset, bytenr);
2317                 if (ret && ret != -ENOENT)
2318                         goto out;
2319
2320                 ret2 = check_delayed_ref(trans, root, path, objectid,
2321                                          offset, bytenr);
2322         } while (ret2 == -EAGAIN);
2323
2324         if (ret2 && ret2 != -ENOENT) {
2325                 ret = ret2;
2326                 goto out;
2327         }
2328
2329         if (ret != -ENOENT || ret2 != -ENOENT)
2330                 ret = 0;
2331 out:
2332         btrfs_free_path(path);
2333         return ret;
2334 }
2335
2336 #if 0
2337 int btrfs_cache_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2338                     struct extent_buffer *buf, u32 nr_extents)
2339 {
2340         struct btrfs_key key;
2341         struct btrfs_file_extent_item *fi;
2342         u64 root_gen;
2343         u32 nritems;
2344         int i;
2345         int level;
2346         int ret = 0;
2347         int shared = 0;
2348
2349         if (!root->ref_cows)
2350                 return 0;
2351
2352         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
2353                 shared = 0;
2354                 root_gen = root->root_key.offset;
2355         } else {
2356                 shared = 1;
2357                 root_gen = trans->transid - 1;
2358         }
2359
2360         level = btrfs_header_level(buf);
2361         nritems = btrfs_header_nritems(buf);
2362
2363         if (level == 0) {
2364                 struct btrfs_leaf_ref *ref;
2365                 struct btrfs_extent_info *info;
2366
2367                 ref = btrfs_alloc_leaf_ref(root, nr_extents);
2368                 if (!ref) {
2369                         ret = -ENOMEM;
2370                         goto out;
2371                 }
2372
2373                 ref->root_gen = root_gen;
2374                 ref->bytenr = buf->start;
2375                 ref->owner = btrfs_header_owner(buf);
2376                 ref->generation = btrfs_header_generation(buf);
2377                 ref->nritems = nr_extents;
2378                 info = ref->extents;
2379
2380                 for (i = 0; nr_extents > 0 && i < nritems; i++) {
2381                         u64 disk_bytenr;
2382                         btrfs_item_key_to_cpu(buf, &key, i);
2383                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2384                                 continue;
2385                         fi = btrfs_item_ptr(buf, i,
2386                                             struct btrfs_file_extent_item);
2387                         if (btrfs_file_extent_type(buf, fi) ==
2388                             BTRFS_FILE_EXTENT_INLINE)
2389                                 continue;
2390                         disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2391                         if (disk_bytenr == 0)
2392                                 continue;
2393
2394                         info->bytenr = disk_bytenr;
2395                         info->num_bytes =
2396                                 btrfs_file_extent_disk_num_bytes(buf, fi);
2397                         info->objectid = key.objectid;
2398                         info->offset = key.offset;
2399                         info++;
2400                 }
2401
2402                 ret = btrfs_add_leaf_ref(root, ref, shared);
2403                 if (ret == -EEXIST && shared) {
2404                         struct btrfs_leaf_ref *old;
2405                         old = btrfs_lookup_leaf_ref(root, ref->bytenr);
2406                         BUG_ON(!old);
2407                         btrfs_remove_leaf_ref(root, old);
2408                         btrfs_free_leaf_ref(root, old);
2409                         ret = btrfs_add_leaf_ref(root, ref, shared);
2410                 }
2411                 WARN_ON(ret);
2412                 btrfs_free_leaf_ref(root, ref);
2413         }
2414 out:
2415         return ret;
2416 }
2417
2418 /* when a block goes through cow, we update the reference counts of
2419  * everything that block points to.  The internal pointers of the block
2420  * can be in just about any order, and it is likely to have clusters of
2421  * things that are close together and clusters of things that are not.
2422  *
2423  * To help reduce the seeks that come with updating all of these reference
2424  * counts, sort them by byte number before actual updates are done.
2425  *
2426  * struct refsort is used to match byte number to slot in the btree block.
2427  * we sort based on the byte number and then use the slot to actually
2428  * find the item.
2429  *
2430  * struct refsort is smaller than strcut btrfs_item and smaller than
2431  * struct btrfs_key_ptr.  Since we're currently limited to the page size
2432  * for a btree block, there's no way for a kmalloc of refsorts for a
2433  * single node to be bigger than a page.
2434  */
2435 struct refsort {
2436         u64 bytenr;
2437         u32 slot;
2438 };
2439
2440 /*
2441  * for passing into sort()
2442  */
2443 static int refsort_cmp(const void *a_void, const void *b_void)
2444 {
2445         const struct refsort *a = a_void;
2446         const struct refsort *b = b_void;
2447
2448         if (a->bytenr < b->bytenr)
2449                 return -1;
2450         if (a->bytenr > b->bytenr)
2451                 return 1;
2452         return 0;
2453 }
2454 #endif
2455
2456 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
2457                            struct btrfs_root *root,
2458                            struct extent_buffer *buf,
2459                            int full_backref, int inc)
2460 {
2461         u64 bytenr;
2462         u64 num_bytes;
2463         u64 parent;
2464         u64 ref_root;
2465         u32 nritems;
2466         struct btrfs_key key;
2467         struct btrfs_file_extent_item *fi;
2468         int i;
2469         int level;
2470         int ret = 0;
2471         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
2472                             u64, u64, u64, u64, u64, u64);
2473
2474         ref_root = btrfs_header_owner(buf);
2475         nritems = btrfs_header_nritems(buf);
2476         level = btrfs_header_level(buf);
2477
2478         if (!root->ref_cows && level == 0)
2479                 return 0;
2480
2481         if (inc)
2482                 process_func = btrfs_inc_extent_ref;
2483         else
2484                 process_func = btrfs_free_extent;
2485
2486         if (full_backref)
2487                 parent = buf->start;
2488         else
2489                 parent = 0;
2490
2491         for (i = 0; i < nritems; i++) {
2492                 if (level == 0) {
2493                         btrfs_item_key_to_cpu(buf, &key, i);
2494                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2495                                 continue;
2496                         fi = btrfs_item_ptr(buf, i,
2497                                             struct btrfs_file_extent_item);
2498                         if (btrfs_file_extent_type(buf, fi) ==
2499                             BTRFS_FILE_EXTENT_INLINE)
2500                                 continue;
2501                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2502                         if (bytenr == 0)
2503                                 continue;
2504
2505                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
2506                         key.offset -= btrfs_file_extent_offset(buf, fi);
2507                         ret = process_func(trans, root, bytenr, num_bytes,
2508                                            parent, ref_root, key.objectid,
2509                                            key.offset);
2510                         if (ret)
2511                                 goto fail;
2512                 } else {
2513                         bytenr = btrfs_node_blockptr(buf, i);
2514                         num_bytes = btrfs_level_size(root, level - 1);
2515                         ret = process_func(trans, root, bytenr, num_bytes,
2516                                            parent, ref_root, level - 1, 0);
2517                         if (ret)
2518                                 goto fail;
2519                 }
2520         }
2521         return 0;
2522 fail:
2523         BUG();
2524         return ret;
2525 }
2526
2527 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2528                   struct extent_buffer *buf, int full_backref)
2529 {
2530         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
2531 }
2532
2533 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2534                   struct extent_buffer *buf, int full_backref)
2535 {
2536         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
2537 }
2538
2539 static int write_one_cache_group(struct btrfs_trans_handle *trans,
2540                                  struct btrfs_root *root,
2541                                  struct btrfs_path *path,
2542                                  struct btrfs_block_group_cache *cache)
2543 {
2544         int ret;
2545         struct btrfs_root *extent_root = root->fs_info->extent_root;
2546         unsigned long bi;
2547         struct extent_buffer *leaf;
2548
2549         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
2550         if (ret < 0)
2551                 goto fail;
2552         BUG_ON(ret);
2553
2554         leaf = path->nodes[0];
2555         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
2556         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
2557         btrfs_mark_buffer_dirty(leaf);
2558         btrfs_release_path(extent_root, path);
2559 fail:
2560         if (ret)
2561                 return ret;
2562         return 0;
2563
2564 }
2565
2566 static struct btrfs_block_group_cache *
2567 next_block_group(struct btrfs_root *root,
2568                  struct btrfs_block_group_cache *cache)
2569 {
2570         struct rb_node *node;
2571         spin_lock(&root->fs_info->block_group_cache_lock);
2572         node = rb_next(&cache->cache_node);
2573         btrfs_put_block_group(cache);
2574         if (node) {
2575                 cache = rb_entry(node, struct btrfs_block_group_cache,
2576                                  cache_node);
2577                 atomic_inc(&cache->count);
2578         } else
2579                 cache = NULL;
2580         spin_unlock(&root->fs_info->block_group_cache_lock);
2581         return cache;
2582 }
2583
2584 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
2585                                    struct btrfs_root *root)
2586 {
2587         struct btrfs_block_group_cache *cache;
2588         int err = 0;
2589         struct btrfs_path *path;
2590         u64 last = 0;
2591
2592         path = btrfs_alloc_path();
2593         if (!path)
2594                 return -ENOMEM;
2595
2596         while (1) {
2597                 if (last == 0) {
2598                         err = btrfs_run_delayed_refs(trans, root,
2599                                                      (unsigned long)-1);
2600                         BUG_ON(err);
2601                 }
2602
2603                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2604                 while (cache) {
2605                         if (cache->dirty)
2606                                 break;
2607                         cache = next_block_group(root, cache);
2608                 }
2609                 if (!cache) {
2610                         if (last == 0)
2611                                 break;
2612                         last = 0;
2613                         continue;
2614                 }
2615
2616                 cache->dirty = 0;
2617                 last = cache->key.objectid + cache->key.offset;
2618
2619                 err = write_one_cache_group(trans, root, path, cache);
2620                 BUG_ON(err);
2621                 btrfs_put_block_group(cache);
2622         }
2623
2624         btrfs_free_path(path);
2625         return 0;
2626 }
2627
2628 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
2629 {
2630         struct btrfs_block_group_cache *block_group;
2631         int readonly = 0;
2632
2633         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
2634         if (!block_group || block_group->ro)
2635                 readonly = 1;
2636         if (block_group)
2637                 btrfs_put_block_group(block_group);
2638         return readonly;
2639 }
2640
2641 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
2642                              u64 total_bytes, u64 bytes_used,
2643                              struct btrfs_space_info **space_info)
2644 {
2645         struct btrfs_space_info *found;
2646
2647         found = __find_space_info(info, flags);
2648         if (found) {
2649                 spin_lock(&found->lock);
2650                 found->total_bytes += total_bytes;
2651                 found->bytes_used += bytes_used;
2652                 found->full = 0;
2653                 spin_unlock(&found->lock);
2654                 *space_info = found;
2655                 return 0;
2656         }
2657         found = kzalloc(sizeof(*found), GFP_NOFS);
2658         if (!found)
2659                 return -ENOMEM;
2660
2661         INIT_LIST_HEAD(&found->block_groups);
2662         init_rwsem(&found->groups_sem);
2663         spin_lock_init(&found->lock);
2664         found->flags = flags;
2665         found->total_bytes = total_bytes;
2666         found->bytes_used = bytes_used;
2667         found->bytes_pinned = 0;
2668         found->bytes_reserved = 0;
2669         found->bytes_readonly = 0;
2670         found->bytes_delalloc = 0;
2671         found->full = 0;
2672         found->force_alloc = 0;
2673         *space_info = found;
2674         list_add_rcu(&found->list, &info->space_info);
2675         atomic_set(&found->caching_threads, 0);
2676         return 0;
2677 }
2678
2679 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
2680 {
2681         u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
2682                                    BTRFS_BLOCK_GROUP_RAID1 |
2683                                    BTRFS_BLOCK_GROUP_RAID10 |
2684                                    BTRFS_BLOCK_GROUP_DUP);
2685         if (extra_flags) {
2686                 if (flags & BTRFS_BLOCK_GROUP_DATA)
2687                         fs_info->avail_data_alloc_bits |= extra_flags;
2688                 if (flags & BTRFS_BLOCK_GROUP_METADATA)
2689                         fs_info->avail_metadata_alloc_bits |= extra_flags;
2690                 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
2691                         fs_info->avail_system_alloc_bits |= extra_flags;
2692         }
2693 }
2694
2695 static void set_block_group_readonly(struct btrfs_block_group_cache *cache)
2696 {
2697         spin_lock(&cache->space_info->lock);
2698         spin_lock(&cache->lock);
2699         if (!cache->ro) {
2700                 cache->space_info->bytes_readonly += cache->key.offset -
2701                                         btrfs_block_group_used(&cache->item);
2702                 cache->ro = 1;
2703         }
2704         spin_unlock(&cache->lock);
2705         spin_unlock(&cache->space_info->lock);
2706 }
2707
2708 u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
2709 {
2710         u64 num_devices = root->fs_info->fs_devices->rw_devices;
2711
2712         if (num_devices == 1)
2713                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
2714         if (num_devices < 4)
2715                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
2716
2717         if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
2718             (flags & (BTRFS_BLOCK_GROUP_RAID1 |
2719                       BTRFS_BLOCK_GROUP_RAID10))) {
2720                 flags &= ~BTRFS_BLOCK_GROUP_DUP;
2721         }
2722
2723         if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
2724             (flags & BTRFS_BLOCK_GROUP_RAID10)) {
2725                 flags &= ~BTRFS_BLOCK_GROUP_RAID1;
2726         }
2727
2728         if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
2729             ((flags & BTRFS_BLOCK_GROUP_RAID1) |
2730              (flags & BTRFS_BLOCK_GROUP_RAID10) |
2731              (flags & BTRFS_BLOCK_GROUP_DUP)))
2732                 flags &= ~BTRFS_BLOCK_GROUP_RAID0;
2733         return flags;
2734 }
2735
2736 static u64 btrfs_get_alloc_profile(struct btrfs_root *root, u64 data)
2737 {
2738         struct btrfs_fs_info *info = root->fs_info;
2739         u64 alloc_profile;
2740
2741         if (data) {
2742                 alloc_profile = info->avail_data_alloc_bits &
2743                         info->data_alloc_profile;
2744                 data = BTRFS_BLOCK_GROUP_DATA | alloc_profile;
2745         } else if (root == root->fs_info->chunk_root) {
2746                 alloc_profile = info->avail_system_alloc_bits &
2747                         info->system_alloc_profile;
2748                 data = BTRFS_BLOCK_GROUP_SYSTEM | alloc_profile;
2749         } else {
2750                 alloc_profile = info->avail_metadata_alloc_bits &
2751                         info->metadata_alloc_profile;
2752                 data = BTRFS_BLOCK_GROUP_METADATA | alloc_profile;
2753         }
2754
2755         return btrfs_reduce_alloc_profile(root, data);
2756 }
2757
2758 void btrfs_set_inode_space_info(struct btrfs_root *root, struct inode *inode)
2759 {
2760         u64 alloc_target;
2761
2762         alloc_target = btrfs_get_alloc_profile(root, 1);
2763         BTRFS_I(inode)->space_info = __find_space_info(root->fs_info,
2764                                                        alloc_target);
2765 }
2766
2767 static u64 calculate_bytes_needed(struct btrfs_root *root, int num_items)
2768 {
2769         u64 num_bytes;
2770         int level;
2771
2772         level = BTRFS_MAX_LEVEL - 2;
2773         /*
2774          * NOTE: these calculations are absolutely the worst possible case.
2775          * This assumes that _every_ item we insert will require a new leaf, and
2776          * that the tree has grown to its maximum level size.
2777          */
2778
2779         /*
2780          * for every item we insert we could insert both an extent item and a
2781          * extent ref item.  Then for ever item we insert, we will need to cow
2782          * both the original leaf, plus the leaf to the left and right of it.
2783          *
2784          * Unless we are talking about the extent root, then we just want the
2785          * number of items * 2, since we just need the extent item plus its ref.
2786          */
2787         if (root == root->fs_info->extent_root)
2788                 num_bytes = num_items * 2;
2789         else
2790                 num_bytes = (num_items + (2 * num_items)) * 3;
2791
2792         /*
2793          * num_bytes is total number of leaves we could need times the leaf
2794          * size, and then for every leaf we could end up cow'ing 2 nodes per
2795          * level, down to the leaf level.
2796          */
2797         num_bytes = (num_bytes * root->leafsize) +
2798                 (num_bytes * (level * 2)) * root->nodesize;
2799
2800         return num_bytes;
2801 }
2802
2803 /*
2804  * Unreserve metadata space for delalloc.  If we have less reserved credits than
2805  * we have extents, this function does nothing.
2806  */
2807 int btrfs_unreserve_metadata_for_delalloc(struct btrfs_root *root,
2808                                           struct inode *inode, int num_items)
2809 {
2810         struct btrfs_fs_info *info = root->fs_info;
2811         struct btrfs_space_info *meta_sinfo;
2812         u64 num_bytes;
2813         u64 alloc_target;
2814         bool bug = false;
2815
2816         /* get the space info for where the metadata will live */
2817         alloc_target = btrfs_get_alloc_profile(root, 0);
2818         meta_sinfo = __find_space_info(info, alloc_target);
2819
2820         num_bytes = calculate_bytes_needed(root->fs_info->extent_root,
2821                                            num_items);
2822
2823         spin_lock(&meta_sinfo->lock);
2824         spin_lock(&BTRFS_I(inode)->accounting_lock);
2825         if (BTRFS_I(inode)->reserved_extents <=
2826             BTRFS_I(inode)->outstanding_extents) {
2827                 spin_unlock(&BTRFS_I(inode)->accounting_lock);
2828                 spin_unlock(&meta_sinfo->lock);
2829                 return 0;
2830         }
2831         spin_unlock(&BTRFS_I(inode)->accounting_lock);
2832
2833         BTRFS_I(inode)->reserved_extents--;
2834         BUG_ON(BTRFS_I(inode)->reserved_extents < 0);
2835
2836         if (meta_sinfo->bytes_delalloc < num_bytes) {
2837                 bug = true;
2838                 meta_sinfo->bytes_delalloc = 0;
2839         } else {
2840                 meta_sinfo->bytes_delalloc -= num_bytes;
2841         }
2842         spin_unlock(&meta_sinfo->lock);
2843
2844         BUG_ON(bug);
2845
2846         return 0;
2847 }
2848
2849 static void check_force_delalloc(struct btrfs_space_info *meta_sinfo)
2850 {
2851         u64 thresh;
2852
2853         thresh = meta_sinfo->bytes_used + meta_sinfo->bytes_reserved +
2854                 meta_sinfo->bytes_pinned + meta_sinfo->bytes_readonly +
2855                 meta_sinfo->bytes_super + meta_sinfo->bytes_root +
2856                 meta_sinfo->bytes_may_use;
2857
2858         thresh = meta_sinfo->total_bytes - thresh;
2859         thresh *= 80;
2860         do_div(thresh, 100);
2861         if (thresh <= meta_sinfo->bytes_delalloc)
2862                 meta_sinfo->force_delalloc = 1;
2863         else
2864                 meta_sinfo->force_delalloc = 0;
2865 }
2866
2867 struct async_flush {
2868         struct btrfs_root *root;
2869         struct btrfs_space_info *info;
2870         struct btrfs_work work;
2871 };
2872
2873 static noinline void flush_delalloc_async(struct btrfs_work *work)
2874 {
2875         struct async_flush *async;
2876         struct btrfs_root *root;
2877         struct btrfs_space_info *info;
2878
2879         async = container_of(work, struct async_flush, work);
2880         root = async->root;
2881         info = async->info;
2882
2883         btrfs_start_delalloc_inodes(root);
2884         wake_up(&info->flush_wait);
2885         btrfs_wait_ordered_extents(root, 0);
2886
2887         spin_lock(&info->lock);
2888         info->flushing = 0;
2889         spin_unlock(&info->lock);
2890         wake_up(&info->flush_wait);
2891
2892         kfree(async);
2893 }
2894
2895 static void wait_on_flush(struct btrfs_space_info *info)
2896 {
2897         DEFINE_WAIT(wait);
2898         u64 used;
2899
2900         while (1) {
2901                 prepare_to_wait(&info->flush_wait, &wait,
2902                                 TASK_UNINTERRUPTIBLE);
2903                 spin_lock(&info->lock);
2904                 if (!info->flushing) {
2905                         spin_unlock(&info->lock);
2906                         break;
2907                 }
2908
2909                 used = info->bytes_used + info->bytes_reserved +
2910                         info->bytes_pinned + info->bytes_readonly +
2911                         info->bytes_super + info->bytes_root +
2912                         info->bytes_may_use + info->bytes_delalloc;
2913                 if (used < info->total_bytes) {
2914                         spin_unlock(&info->lock);
2915                         break;
2916                 }
2917                 spin_unlock(&info->lock);
2918                 schedule();
2919         }
2920         finish_wait(&info->flush_wait, &wait);
2921 }
2922
2923 static void flush_delalloc(struct btrfs_root *root,
2924                                  struct btrfs_space_info *info)
2925 {
2926         struct async_flush *async;
2927         bool wait = false;
2928
2929         spin_lock(&info->lock);
2930
2931         if (!info->flushing) {
2932                 info->flushing = 1;
2933                 init_waitqueue_head(&info->flush_wait);
2934         } else {
2935                 wait = true;
2936         }
2937
2938         spin_unlock(&info->lock);
2939
2940         if (wait) {
2941                 wait_on_flush(info);
2942                 return;
2943         }
2944
2945         async = kzalloc(sizeof(*async), GFP_NOFS);
2946         if (!async)
2947                 goto flush;
2948
2949         async->root = root;
2950         async->info = info;
2951         async->work.func = flush_delalloc_async;
2952
2953         btrfs_queue_worker(&root->fs_info->enospc_workers,
2954                            &async->work);
2955         wait_on_flush(info);
2956         return;
2957
2958 flush:
2959         btrfs_start_delalloc_inodes(root);
2960         btrfs_wait_ordered_extents(root, 0);
2961
2962         spin_lock(&info->lock);
2963         info->flushing = 0;
2964         spin_unlock(&info->lock);
2965         wake_up(&info->flush_wait);
2966 }
2967
2968 static int maybe_allocate_chunk(struct btrfs_root *root,
2969                                  struct btrfs_space_info *info)
2970 {
2971         struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
2972         struct btrfs_trans_handle *trans;
2973         bool wait = false;
2974         int ret = 0;
2975         u64 min_metadata;
2976         u64 free_space;
2977
2978         free_space = btrfs_super_total_bytes(disk_super);
2979         /*
2980          * we allow the metadata to grow to a max of either 10gb or 5% of the
2981          * space in the volume.
2982          */
2983         min_metadata = min((u64)10 * 1024 * 1024 * 1024,
2984                              div64_u64(free_space * 5, 100));
2985         if (info->total_bytes >= min_metadata) {
2986                 spin_unlock(&info->lock);
2987                 return 0;
2988         }
2989
2990         if (info->full) {
2991                 spin_unlock(&info->lock);
2992                 return 0;
2993         }
2994
2995         if (!info->allocating_chunk) {
2996                 info->force_alloc = 1;
2997                 info->allocating_chunk = 1;
2998                 init_waitqueue_head(&info->allocate_wait);
2999         } else {
3000                 wait = true;
3001         }
3002
3003         spin_unlock(&info->lock);
3004
3005         if (wait) {
3006                 wait_event(info->allocate_wait,
3007                            !info->allocating_chunk);
3008                 return 1;
3009         }
3010
3011         trans = btrfs_start_transaction(root, 1);
3012         if (!trans) {
3013                 ret = -ENOMEM;
3014                 goto out;
3015         }
3016
3017         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3018                              4096 + 2 * 1024 * 1024,
3019                              info->flags, 0);
3020         btrfs_end_transaction(trans, root);
3021         if (ret)
3022                 goto out;
3023 out:
3024         spin_lock(&info->lock);
3025         info->allocating_chunk = 0;
3026         spin_unlock(&info->lock);
3027         wake_up(&info->allocate_wait);
3028
3029         if (ret)
3030                 return 0;
3031         return 1;
3032 }
3033
3034 /*
3035  * Reserve metadata space for delalloc.
3036  */
3037 int btrfs_reserve_metadata_for_delalloc(struct btrfs_root *root,
3038                                         struct inode *inode, int num_items)
3039 {
3040         struct btrfs_fs_info *info = root->fs_info;
3041         struct btrfs_space_info *meta_sinfo;
3042         u64 num_bytes;
3043         u64 used;
3044         u64 alloc_target;
3045         int flushed = 0;
3046         int force_delalloc;
3047
3048         /* get the space info for where the metadata will live */
3049         alloc_target = btrfs_get_alloc_profile(root, 0);
3050         meta_sinfo = __find_space_info(info, alloc_target);
3051
3052         num_bytes = calculate_bytes_needed(root->fs_info->extent_root,
3053                                            num_items);
3054 again:
3055         spin_lock(&meta_sinfo->lock);
3056
3057         force_delalloc = meta_sinfo->force_delalloc;
3058
3059         if (unlikely(!meta_sinfo->bytes_root))
3060                 meta_sinfo->bytes_root = calculate_bytes_needed(root, 6);
3061
3062         if (!flushed)
3063                 meta_sinfo->bytes_delalloc += num_bytes;
3064
3065         used = meta_sinfo->bytes_used + meta_sinfo->bytes_reserved +
3066                 meta_sinfo->bytes_pinned + meta_sinfo->bytes_readonly +
3067                 meta_sinfo->bytes_super + meta_sinfo->bytes_root +
3068                 meta_sinfo->bytes_may_use + meta_sinfo->bytes_delalloc;
3069
3070         if (used > meta_sinfo->total_bytes) {
3071                 flushed++;
3072
3073                 if (flushed == 1) {
3074                         if (maybe_allocate_chunk(root, meta_sinfo))
3075                                 goto again;
3076                         flushed++;
3077                 } else {
3078                         spin_unlock(&meta_sinfo->lock);
3079                 }
3080
3081                 if (flushed == 2) {
3082                         filemap_flush(inode->i_mapping);
3083                         goto again;
3084                 } else if (flushed == 3) {
3085                         flush_delalloc(root, meta_sinfo);
3086                         goto again;
3087                 }
3088                 spin_lock(&meta_sinfo->lock);
3089                 meta_sinfo->bytes_delalloc -= num_bytes;
3090                 spin_unlock(&meta_sinfo->lock);
3091                 printk(KERN_ERR "enospc, has %d, reserved %d\n",
3092                        BTRFS_I(inode)->outstanding_extents,
3093                        BTRFS_I(inode)->reserved_extents);
3094                 dump_space_info(meta_sinfo, 0, 0);
3095                 return -ENOSPC;
3096         }
3097
3098         BTRFS_I(inode)->reserved_extents++;
3099         check_force_delalloc(meta_sinfo);
3100         spin_unlock(&meta_sinfo->lock);
3101
3102         if (!flushed && force_delalloc)
3103                 filemap_flush(inode->i_mapping);
3104
3105         return 0;
3106 }
3107
3108 /*
3109  * unreserve num_items number of items worth of metadata space.  This needs to
3110  * be paired with btrfs_reserve_metadata_space.
3111  *
3112  * NOTE: if you have the option, run this _AFTER_ you do a
3113  * btrfs_end_transaction, since btrfs_end_transaction will run delayed ref
3114  * oprations which will result in more used metadata, so we want to make sure we
3115  * can do that without issue.
3116  */
3117 int btrfs_unreserve_metadata_space(struct btrfs_root *root, int num_items)
3118 {
3119         struct btrfs_fs_info *info = root->fs_info;
3120         struct btrfs_space_info *meta_sinfo;
3121         u64 num_bytes;
3122         u64 alloc_target;
3123         bool bug = false;
3124
3125         /* get the space info for where the metadata will live */
3126         alloc_target = btrfs_get_alloc_profile(root, 0);
3127         meta_sinfo = __find_space_info(info, alloc_target);
3128
3129         num_bytes = calculate_bytes_needed(root, num_items);
3130
3131         spin_lock(&meta_sinfo->lock);
3132         if (meta_sinfo->bytes_may_use < num_bytes) {
3133                 bug = true;
3134                 meta_sinfo->bytes_may_use = 0;
3135         } else {
3136                 meta_sinfo->bytes_may_use -= num_bytes;
3137         }
3138         spin_unlock(&meta_sinfo->lock);
3139
3140         BUG_ON(bug);
3141
3142         return 0;
3143 }
3144
3145 /*
3146  * Reserve some metadata space for use.  We'll calculate the worste case number
3147  * of bytes that would be needed to modify num_items number of items.  If we
3148  * have space, fantastic, if not, you get -ENOSPC.  Please call
3149  * btrfs_unreserve_metadata_space when you are done for the _SAME_ number of
3150  * items you reserved, since whatever metadata you needed should have already
3151  * been allocated.
3152  *
3153  * This will commit the transaction to make more space if we don't have enough
3154  * metadata space.  THe only time we don't do this is if we're reserving space
3155  * inside of a transaction, then we will just return -ENOSPC and it is the
3156  * callers responsibility to handle it properly.
3157  */
3158 int btrfs_reserve_metadata_space(struct btrfs_root *root, int num_items)
3159 {
3160         struct btrfs_fs_info *info = root->fs_info;
3161         struct btrfs_space_info *meta_sinfo;
3162         u64 num_bytes;
3163         u64 used;
3164         u64 alloc_target;
3165         int retries = 0;
3166
3167         /* get the space info for where the metadata will live */
3168         alloc_target = btrfs_get_alloc_profile(root, 0);
3169         meta_sinfo = __find_space_info(info, alloc_target);
3170
3171         num_bytes = calculate_bytes_needed(root, num_items);
3172 again:
3173         spin_lock(&meta_sinfo->lock);
3174
3175         if (unlikely(!meta_sinfo->bytes_root))
3176                 meta_sinfo->bytes_root = calculate_bytes_needed(root, 6);
3177
3178         if (!retries)
3179                 meta_sinfo->bytes_may_use += num_bytes;
3180
3181         used = meta_sinfo->bytes_used + meta_sinfo->bytes_reserved +
3182                 meta_sinfo->bytes_pinned + meta_sinfo->bytes_readonly +
3183                 meta_sinfo->bytes_super + meta_sinfo->bytes_root +
3184                 meta_sinfo->bytes_may_use + meta_sinfo->bytes_delalloc;
3185
3186         if (used > meta_sinfo->total_bytes) {
3187                 retries++;
3188                 if (retries == 1) {
3189                         if (maybe_allocate_chunk(root, meta_sinfo))
3190                                 goto again;
3191                         retries++;
3192                 } else {
3193                         spin_unlock(&meta_sinfo->lock);
3194                 }
3195
3196                 if (retries == 2) {
3197                         flush_delalloc(root, meta_sinfo);
3198                         goto again;
3199                 }
3200                 spin_lock(&meta_sinfo->lock);