bcf303204f7f5f3473eaa7a907423ef998274f4d
[linux-3.10.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 <linux/slab.h>
26 #include "compat.h"
27 #include "hash.h"
28 #include "ctree.h"
29 #include "disk-io.h"
30 #include "print-tree.h"
31 #include "transaction.h"
32 #include "volumes.h"
33 #include "locking.h"
34 #include "free-space-cache.h"
35
36 static int update_block_group(struct btrfs_trans_handle *trans,
37                               struct btrfs_root *root,
38                               u64 bytenr, u64 num_bytes, int alloc);
39 static int update_reserved_bytes(struct btrfs_block_group_cache *cache,
40                                  u64 num_bytes, int reserve, int sinfo);
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 find_next_key(struct btrfs_path *path, int level,
64                          struct btrfs_key *key);
65 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
66                             int dump_block_groups);
67
68 static noinline int
69 block_group_cache_done(struct btrfs_block_group_cache *cache)
70 {
71         smp_mb();
72         return cache->cached == BTRFS_CACHE_FINISHED;
73 }
74
75 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
76 {
77         return (cache->flags & bits) == bits;
78 }
79
80 void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
81 {
82         atomic_inc(&cache->count);
83 }
84
85 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
86 {
87         if (atomic_dec_and_test(&cache->count)) {
88                 WARN_ON(cache->pinned > 0);
89                 WARN_ON(cache->reserved > 0);
90                 WARN_ON(cache->reserved_pinned > 0);
91                 kfree(cache);
92         }
93 }
94
95 /*
96  * this adds the block group to the fs_info rb tree for the block group
97  * cache
98  */
99 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
100                                 struct btrfs_block_group_cache *block_group)
101 {
102         struct rb_node **p;
103         struct rb_node *parent = NULL;
104         struct btrfs_block_group_cache *cache;
105
106         spin_lock(&info->block_group_cache_lock);
107         p = &info->block_group_cache_tree.rb_node;
108
109         while (*p) {
110                 parent = *p;
111                 cache = rb_entry(parent, struct btrfs_block_group_cache,
112                                  cache_node);
113                 if (block_group->key.objectid < cache->key.objectid) {
114                         p = &(*p)->rb_left;
115                 } else if (block_group->key.objectid > cache->key.objectid) {
116                         p = &(*p)->rb_right;
117                 } else {
118                         spin_unlock(&info->block_group_cache_lock);
119                         return -EEXIST;
120                 }
121         }
122
123         rb_link_node(&block_group->cache_node, parent, p);
124         rb_insert_color(&block_group->cache_node,
125                         &info->block_group_cache_tree);
126         spin_unlock(&info->block_group_cache_lock);
127
128         return 0;
129 }
130
131 /*
132  * This will return the block group at or after bytenr if contains is 0, else
133  * it will return the block group that contains the bytenr
134  */
135 static struct btrfs_block_group_cache *
136 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
137                               int contains)
138 {
139         struct btrfs_block_group_cache *cache, *ret = NULL;
140         struct rb_node *n;
141         u64 end, start;
142
143         spin_lock(&info->block_group_cache_lock);
144         n = info->block_group_cache_tree.rb_node;
145
146         while (n) {
147                 cache = rb_entry(n, struct btrfs_block_group_cache,
148                                  cache_node);
149                 end = cache->key.objectid + cache->key.offset - 1;
150                 start = cache->key.objectid;
151
152                 if (bytenr < start) {
153                         if (!contains && (!ret || start < ret->key.objectid))
154                                 ret = cache;
155                         n = n->rb_left;
156                 } else if (bytenr > start) {
157                         if (contains && bytenr <= end) {
158                                 ret = cache;
159                                 break;
160                         }
161                         n = n->rb_right;
162                 } else {
163                         ret = cache;
164                         break;
165                 }
166         }
167         if (ret)
168                 btrfs_get_block_group(ret);
169         spin_unlock(&info->block_group_cache_lock);
170
171         return ret;
172 }
173
174 static int add_excluded_extent(struct btrfs_root *root,
175                                u64 start, u64 num_bytes)
176 {
177         u64 end = start + num_bytes - 1;
178         set_extent_bits(&root->fs_info->freed_extents[0],
179                         start, end, EXTENT_UPTODATE, GFP_NOFS);
180         set_extent_bits(&root->fs_info->freed_extents[1],
181                         start, end, EXTENT_UPTODATE, GFP_NOFS);
182         return 0;
183 }
184
185 static void free_excluded_extents(struct btrfs_root *root,
186                                   struct btrfs_block_group_cache *cache)
187 {
188         u64 start, end;
189
190         start = cache->key.objectid;
191         end = start + cache->key.offset - 1;
192
193         clear_extent_bits(&root->fs_info->freed_extents[0],
194                           start, end, EXTENT_UPTODATE, GFP_NOFS);
195         clear_extent_bits(&root->fs_info->freed_extents[1],
196                           start, end, EXTENT_UPTODATE, GFP_NOFS);
197 }
198
199 static int exclude_super_stripes(struct btrfs_root *root,
200                                  struct btrfs_block_group_cache *cache)
201 {
202         u64 bytenr;
203         u64 *logical;
204         int stripe_len;
205         int i, nr, ret;
206
207         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
208                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
209                 cache->bytes_super += stripe_len;
210                 ret = add_excluded_extent(root, cache->key.objectid,
211                                           stripe_len);
212                 BUG_ON(ret);
213         }
214
215         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
216                 bytenr = btrfs_sb_offset(i);
217                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
218                                        cache->key.objectid, bytenr,
219                                        0, &logical, &nr, &stripe_len);
220                 BUG_ON(ret);
221
222                 while (nr--) {
223                         cache->bytes_super += stripe_len;
224                         ret = add_excluded_extent(root, logical[nr],
225                                                   stripe_len);
226                         BUG_ON(ret);
227                 }
228
229                 kfree(logical);
230         }
231         return 0;
232 }
233
234 static struct btrfs_caching_control *
235 get_caching_control(struct btrfs_block_group_cache *cache)
236 {
237         struct btrfs_caching_control *ctl;
238
239         spin_lock(&cache->lock);
240         if (cache->cached != BTRFS_CACHE_STARTED) {
241                 spin_unlock(&cache->lock);
242                 return NULL;
243         }
244
245         /* We're loading it the fast way, so we don't have a caching_ctl. */
246         if (!cache->caching_ctl) {
247                 spin_unlock(&cache->lock);
248                 return NULL;
249         }
250
251         ctl = cache->caching_ctl;
252         atomic_inc(&ctl->count);
253         spin_unlock(&cache->lock);
254         return ctl;
255 }
256
257 static void put_caching_control(struct btrfs_caching_control *ctl)
258 {
259         if (atomic_dec_and_test(&ctl->count))
260                 kfree(ctl);
261 }
262
263 /*
264  * this is only called by cache_block_group, since we could have freed extents
265  * we need to check the pinned_extents for any extents that can't be used yet
266  * since their free space will be released as soon as the transaction commits.
267  */
268 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
269                               struct btrfs_fs_info *info, u64 start, u64 end)
270 {
271         u64 extent_start, extent_end, size, total_added = 0;
272         int ret;
273
274         while (start < end) {
275                 ret = find_first_extent_bit(info->pinned_extents, start,
276                                             &extent_start, &extent_end,
277                                             EXTENT_DIRTY | EXTENT_UPTODATE);
278                 if (ret)
279                         break;
280
281                 if (extent_start <= start) {
282                         start = extent_end + 1;
283                 } else if (extent_start > start && extent_start < end) {
284                         size = extent_start - start;
285                         total_added += size;
286                         ret = btrfs_add_free_space(block_group, start,
287                                                    size);
288                         BUG_ON(ret);
289                         start = extent_end + 1;
290                 } else {
291                         break;
292                 }
293         }
294
295         if (start < end) {
296                 size = end - start;
297                 total_added += size;
298                 ret = btrfs_add_free_space(block_group, start, size);
299                 BUG_ON(ret);
300         }
301
302         return total_added;
303 }
304
305 static int caching_kthread(void *data)
306 {
307         struct btrfs_block_group_cache *block_group = data;
308         struct btrfs_fs_info *fs_info = block_group->fs_info;
309         struct btrfs_caching_control *caching_ctl = block_group->caching_ctl;
310         struct btrfs_root *extent_root = fs_info->extent_root;
311         struct btrfs_path *path;
312         struct extent_buffer *leaf;
313         struct btrfs_key key;
314         u64 total_found = 0;
315         u64 last = 0;
316         u32 nritems;
317         int ret = 0;
318
319         path = btrfs_alloc_path();
320         if (!path)
321                 return -ENOMEM;
322
323         exclude_super_stripes(extent_root, block_group);
324         spin_lock(&block_group->space_info->lock);
325         block_group->space_info->bytes_readonly += block_group->bytes_super;
326         spin_unlock(&block_group->space_info->lock);
327
328         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
329
330         /*
331          * We don't want to deadlock with somebody trying to allocate a new
332          * extent for the extent root while also trying to search the extent
333          * root to add free space.  So we skip locking and search the commit
334          * root, since its read-only
335          */
336         path->skip_locking = 1;
337         path->search_commit_root = 1;
338         path->reada = 2;
339
340         key.objectid = last;
341         key.offset = 0;
342         key.type = BTRFS_EXTENT_ITEM_KEY;
343 again:
344         mutex_lock(&caching_ctl->mutex);
345         /* need to make sure the commit_root doesn't disappear */
346         down_read(&fs_info->extent_commit_sem);
347
348         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
349         if (ret < 0)
350                 goto err;
351
352         leaf = path->nodes[0];
353         nritems = btrfs_header_nritems(leaf);
354
355         while (1) {
356                 smp_mb();
357                 if (fs_info->closing > 1) {
358                         last = (u64)-1;
359                         break;
360                 }
361
362                 if (path->slots[0] < nritems) {
363                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
364                 } else {
365                         ret = find_next_key(path, 0, &key);
366                         if (ret)
367                                 break;
368
369                         caching_ctl->progress = last;
370                         btrfs_release_path(extent_root, path);
371                         up_read(&fs_info->extent_commit_sem);
372                         mutex_unlock(&caching_ctl->mutex);
373                         if (btrfs_transaction_in_commit(fs_info))
374                                 schedule_timeout(1);
375                         else
376                                 cond_resched();
377                         goto again;
378                 }
379
380                 if (key.objectid < block_group->key.objectid) {
381                         path->slots[0]++;
382                         continue;
383                 }
384
385                 if (key.objectid >= block_group->key.objectid +
386                     block_group->key.offset)
387                         break;
388
389                 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
390                         total_found += add_new_free_space(block_group,
391                                                           fs_info, last,
392                                                           key.objectid);
393                         last = key.objectid + key.offset;
394
395                         if (total_found > (1024 * 1024 * 2)) {
396                                 total_found = 0;
397                                 wake_up(&caching_ctl->wait);
398                         }
399                 }
400                 path->slots[0]++;
401         }
402         ret = 0;
403
404         total_found += add_new_free_space(block_group, fs_info, last,
405                                           block_group->key.objectid +
406                                           block_group->key.offset);
407         caching_ctl->progress = (u64)-1;
408
409         spin_lock(&block_group->lock);
410         block_group->caching_ctl = NULL;
411         block_group->cached = BTRFS_CACHE_FINISHED;
412         spin_unlock(&block_group->lock);
413
414 err:
415         btrfs_free_path(path);
416         up_read(&fs_info->extent_commit_sem);
417
418         free_excluded_extents(extent_root, block_group);
419
420         mutex_unlock(&caching_ctl->mutex);
421         wake_up(&caching_ctl->wait);
422
423         put_caching_control(caching_ctl);
424         atomic_dec(&block_group->space_info->caching_threads);
425         btrfs_put_block_group(block_group);
426
427         return 0;
428 }
429
430 static int cache_block_group(struct btrfs_block_group_cache *cache,
431                              struct btrfs_trans_handle *trans,
432                              struct btrfs_root *root,
433                              int load_cache_only)
434 {
435         struct btrfs_fs_info *fs_info = cache->fs_info;
436         struct btrfs_caching_control *caching_ctl;
437         struct task_struct *tsk;
438         int ret = 0;
439
440         smp_mb();
441         if (cache->cached != BTRFS_CACHE_NO)
442                 return 0;
443
444         /*
445          * We can't do the read from on-disk cache during a commit since we need
446          * to have the normal tree locking.  Also if we are currently trying to
447          * allocate blocks for the tree root we can't do the fast caching since
448          * we likely hold important locks.
449          */
450         if (!trans->transaction->in_commit &&
451             (root && root != root->fs_info->tree_root)) {
452                 spin_lock(&cache->lock);
453                 if (cache->cached != BTRFS_CACHE_NO) {
454                         spin_unlock(&cache->lock);
455                         return 0;
456                 }
457                 cache->cached = BTRFS_CACHE_STARTED;
458                 spin_unlock(&cache->lock);
459
460                 ret = load_free_space_cache(fs_info, cache);
461
462                 spin_lock(&cache->lock);
463                 if (ret == 1) {
464                         cache->cached = BTRFS_CACHE_FINISHED;
465                         cache->last_byte_to_unpin = (u64)-1;
466                 } else {
467                         cache->cached = BTRFS_CACHE_NO;
468                 }
469                 spin_unlock(&cache->lock);
470                 if (ret == 1)
471                         return 0;
472         }
473
474         if (load_cache_only)
475                 return 0;
476
477         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_KERNEL);
478         BUG_ON(!caching_ctl);
479
480         INIT_LIST_HEAD(&caching_ctl->list);
481         mutex_init(&caching_ctl->mutex);
482         init_waitqueue_head(&caching_ctl->wait);
483         caching_ctl->block_group = cache;
484         caching_ctl->progress = cache->key.objectid;
485         /* one for caching kthread, one for caching block group list */
486         atomic_set(&caching_ctl->count, 2);
487
488         spin_lock(&cache->lock);
489         if (cache->cached != BTRFS_CACHE_NO) {
490                 spin_unlock(&cache->lock);
491                 kfree(caching_ctl);
492                 return 0;
493         }
494         cache->caching_ctl = caching_ctl;
495         cache->cached = BTRFS_CACHE_STARTED;
496         spin_unlock(&cache->lock);
497
498         down_write(&fs_info->extent_commit_sem);
499         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
500         up_write(&fs_info->extent_commit_sem);
501
502         atomic_inc(&cache->space_info->caching_threads);
503         btrfs_get_block_group(cache);
504
505         tsk = kthread_run(caching_kthread, cache, "btrfs-cache-%llu\n",
506                           cache->key.objectid);
507         if (IS_ERR(tsk)) {
508                 ret = PTR_ERR(tsk);
509                 printk(KERN_ERR "error running thread %d\n", ret);
510                 BUG();
511         }
512
513         return ret;
514 }
515
516 /*
517  * return the block group that starts at or after bytenr
518  */
519 static struct btrfs_block_group_cache *
520 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
521 {
522         struct btrfs_block_group_cache *cache;
523
524         cache = block_group_cache_tree_search(info, bytenr, 0);
525
526         return cache;
527 }
528
529 /*
530  * return the block group that contains the given bytenr
531  */
532 struct btrfs_block_group_cache *btrfs_lookup_block_group(
533                                                  struct btrfs_fs_info *info,
534                                                  u64 bytenr)
535 {
536         struct btrfs_block_group_cache *cache;
537
538         cache = block_group_cache_tree_search(info, bytenr, 1);
539
540         return cache;
541 }
542
543 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
544                                                   u64 flags)
545 {
546         struct list_head *head = &info->space_info;
547         struct btrfs_space_info *found;
548
549         flags &= BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_SYSTEM |
550                  BTRFS_BLOCK_GROUP_METADATA;
551
552         rcu_read_lock();
553         list_for_each_entry_rcu(found, head, list) {
554                 if (found->flags & flags) {
555                         rcu_read_unlock();
556                         return found;
557                 }
558         }
559         rcu_read_unlock();
560         return NULL;
561 }
562
563 /*
564  * after adding space to the filesystem, we need to clear the full flags
565  * on all the space infos.
566  */
567 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
568 {
569         struct list_head *head = &info->space_info;
570         struct btrfs_space_info *found;
571
572         rcu_read_lock();
573         list_for_each_entry_rcu(found, head, list)
574                 found->full = 0;
575         rcu_read_unlock();
576 }
577
578 static u64 div_factor(u64 num, int factor)
579 {
580         if (factor == 10)
581                 return num;
582         num *= factor;
583         do_div(num, 10);
584         return num;
585 }
586
587 static u64 div_factor_fine(u64 num, int factor)
588 {
589         if (factor == 100)
590                 return num;
591         num *= factor;
592         do_div(num, 100);
593         return num;
594 }
595
596 u64 btrfs_find_block_group(struct btrfs_root *root,
597                            u64 search_start, u64 search_hint, int owner)
598 {
599         struct btrfs_block_group_cache *cache;
600         u64 used;
601         u64 last = max(search_hint, search_start);
602         u64 group_start = 0;
603         int full_search = 0;
604         int factor = 9;
605         int wrapped = 0;
606 again:
607         while (1) {
608                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
609                 if (!cache)
610                         break;
611
612                 spin_lock(&cache->lock);
613                 last = cache->key.objectid + cache->key.offset;
614                 used = btrfs_block_group_used(&cache->item);
615
616                 if ((full_search || !cache->ro) &&
617                     block_group_bits(cache, BTRFS_BLOCK_GROUP_METADATA)) {
618                         if (used + cache->pinned + cache->reserved <
619                             div_factor(cache->key.offset, factor)) {
620                                 group_start = cache->key.objectid;
621                                 spin_unlock(&cache->lock);
622                                 btrfs_put_block_group(cache);
623                                 goto found;
624                         }
625                 }
626                 spin_unlock(&cache->lock);
627                 btrfs_put_block_group(cache);
628                 cond_resched();
629         }
630         if (!wrapped) {
631                 last = search_start;
632                 wrapped = 1;
633                 goto again;
634         }
635         if (!full_search && factor < 10) {
636                 last = search_start;
637                 full_search = 1;
638                 factor = 10;
639                 goto again;
640         }
641 found:
642         return group_start;
643 }
644
645 /* simple helper to search for an existing extent at a given offset */
646 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
647 {
648         int ret;
649         struct btrfs_key key;
650         struct btrfs_path *path;
651
652         path = btrfs_alloc_path();
653         BUG_ON(!path);
654         key.objectid = start;
655         key.offset = len;
656         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
657         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
658                                 0, 0);
659         btrfs_free_path(path);
660         return ret;
661 }
662
663 /*
664  * helper function to lookup reference count and flags of extent.
665  *
666  * the head node for delayed ref is used to store the sum of all the
667  * reference count modifications queued up in the rbtree. the head
668  * node may also store the extent flags to set. This way you can check
669  * to see what the reference count and extent flags would be if all of
670  * the delayed refs are not processed.
671  */
672 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
673                              struct btrfs_root *root, u64 bytenr,
674                              u64 num_bytes, u64 *refs, u64 *flags)
675 {
676         struct btrfs_delayed_ref_head *head;
677         struct btrfs_delayed_ref_root *delayed_refs;
678         struct btrfs_path *path;
679         struct btrfs_extent_item *ei;
680         struct extent_buffer *leaf;
681         struct btrfs_key key;
682         u32 item_size;
683         u64 num_refs;
684         u64 extent_flags;
685         int ret;
686
687         path = btrfs_alloc_path();
688         if (!path)
689                 return -ENOMEM;
690
691         key.objectid = bytenr;
692         key.type = BTRFS_EXTENT_ITEM_KEY;
693         key.offset = num_bytes;
694         if (!trans) {
695                 path->skip_locking = 1;
696                 path->search_commit_root = 1;
697         }
698 again:
699         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
700                                 &key, path, 0, 0);
701         if (ret < 0)
702                 goto out_free;
703
704         if (ret == 0) {
705                 leaf = path->nodes[0];
706                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
707                 if (item_size >= sizeof(*ei)) {
708                         ei = btrfs_item_ptr(leaf, path->slots[0],
709                                             struct btrfs_extent_item);
710                         num_refs = btrfs_extent_refs(leaf, ei);
711                         extent_flags = btrfs_extent_flags(leaf, ei);
712                 } else {
713 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
714                         struct btrfs_extent_item_v0 *ei0;
715                         BUG_ON(item_size != sizeof(*ei0));
716                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
717                                              struct btrfs_extent_item_v0);
718                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
719                         /* FIXME: this isn't correct for data */
720                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
721 #else
722                         BUG();
723 #endif
724                 }
725                 BUG_ON(num_refs == 0);
726         } else {
727                 num_refs = 0;
728                 extent_flags = 0;
729                 ret = 0;
730         }
731
732         if (!trans)
733                 goto out;
734
735         delayed_refs = &trans->transaction->delayed_refs;
736         spin_lock(&delayed_refs->lock);
737         head = btrfs_find_delayed_ref_head(trans, bytenr);
738         if (head) {
739                 if (!mutex_trylock(&head->mutex)) {
740                         atomic_inc(&head->node.refs);
741                         spin_unlock(&delayed_refs->lock);
742
743                         btrfs_release_path(root->fs_info->extent_root, path);
744
745                         mutex_lock(&head->mutex);
746                         mutex_unlock(&head->mutex);
747                         btrfs_put_delayed_ref(&head->node);
748                         goto again;
749                 }
750                 if (head->extent_op && head->extent_op->update_flags)
751                         extent_flags |= head->extent_op->flags_to_set;
752                 else
753                         BUG_ON(num_refs == 0);
754
755                 num_refs += head->node.ref_mod;
756                 mutex_unlock(&head->mutex);
757         }
758         spin_unlock(&delayed_refs->lock);
759 out:
760         WARN_ON(num_refs == 0);
761         if (refs)
762                 *refs = num_refs;
763         if (flags)
764                 *flags = extent_flags;
765 out_free:
766         btrfs_free_path(path);
767         return ret;
768 }
769
770 /*
771  * Back reference rules.  Back refs have three main goals:
772  *
773  * 1) differentiate between all holders of references to an extent so that
774  *    when a reference is dropped we can make sure it was a valid reference
775  *    before freeing the extent.
776  *
777  * 2) Provide enough information to quickly find the holders of an extent
778  *    if we notice a given block is corrupted or bad.
779  *
780  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
781  *    maintenance.  This is actually the same as #2, but with a slightly
782  *    different use case.
783  *
784  * There are two kinds of back refs. The implicit back refs is optimized
785  * for pointers in non-shared tree blocks. For a given pointer in a block,
786  * back refs of this kind provide information about the block's owner tree
787  * and the pointer's key. These information allow us to find the block by
788  * b-tree searching. The full back refs is for pointers in tree blocks not
789  * referenced by their owner trees. The location of tree block is recorded
790  * in the back refs. Actually the full back refs is generic, and can be
791  * used in all cases the implicit back refs is used. The major shortcoming
792  * of the full back refs is its overhead. Every time a tree block gets
793  * COWed, we have to update back refs entry for all pointers in it.
794  *
795  * For a newly allocated tree block, we use implicit back refs for
796  * pointers in it. This means most tree related operations only involve
797  * implicit back refs. For a tree block created in old transaction, the
798  * only way to drop a reference to it is COW it. So we can detect the
799  * event that tree block loses its owner tree's reference and do the
800  * back refs conversion.
801  *
802  * When a tree block is COW'd through a tree, there are four cases:
803  *
804  * The reference count of the block is one and the tree is the block's
805  * owner tree. Nothing to do in this case.
806  *
807  * The reference count of the block is one and the tree is not the
808  * block's owner tree. In this case, full back refs is used for pointers
809  * in the block. Remove these full back refs, add implicit back refs for
810  * every pointers in the new block.
811  *
812  * The reference count of the block is greater than one and the tree is
813  * the block's owner tree. In this case, implicit back refs is used for
814  * pointers in the block. Add full back refs for every pointers in the
815  * block, increase lower level extents' reference counts. The original
816  * implicit back refs are entailed to the new block.
817  *
818  * The reference count of the block is greater than one and the tree is
819  * not the block's owner tree. Add implicit back refs for every pointer in
820  * the new block, increase lower level extents' reference count.
821  *
822  * Back Reference Key composing:
823  *
824  * The key objectid corresponds to the first byte in the extent,
825  * The key type is used to differentiate between types of back refs.
826  * There are different meanings of the key offset for different types
827  * of back refs.
828  *
829  * File extents can be referenced by:
830  *
831  * - multiple snapshots, subvolumes, or different generations in one subvol
832  * - different files inside a single subvolume
833  * - different offsets inside a file (bookend extents in file.c)
834  *
835  * The extent ref structure for the implicit back refs has fields for:
836  *
837  * - Objectid of the subvolume root
838  * - objectid of the file holding the reference
839  * - original offset in the file
840  * - how many bookend extents
841  *
842  * The key offset for the implicit back refs is hash of the first
843  * three fields.
844  *
845  * The extent ref structure for the full back refs has field for:
846  *
847  * - number of pointers in the tree leaf
848  *
849  * The key offset for the implicit back refs is the first byte of
850  * the tree leaf
851  *
852  * When a file extent is allocated, The implicit back refs is used.
853  * the fields are filled in:
854  *
855  *     (root_key.objectid, inode objectid, offset in file, 1)
856  *
857  * When a file extent is removed file truncation, we find the
858  * corresponding implicit back refs and check the following fields:
859  *
860  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
861  *
862  * Btree extents can be referenced by:
863  *
864  * - Different subvolumes
865  *
866  * Both the implicit back refs and the full back refs for tree blocks
867  * only consist of key. The key offset for the implicit back refs is
868  * objectid of block's owner tree. The key offset for the full back refs
869  * is the first byte of parent block.
870  *
871  * When implicit back refs is used, information about the lowest key and
872  * level of the tree block are required. These information are stored in
873  * tree block info structure.
874  */
875
876 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
877 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
878                                   struct btrfs_root *root,
879                                   struct btrfs_path *path,
880                                   u64 owner, u32 extra_size)
881 {
882         struct btrfs_extent_item *item;
883         struct btrfs_extent_item_v0 *ei0;
884         struct btrfs_extent_ref_v0 *ref0;
885         struct btrfs_tree_block_info *bi;
886         struct extent_buffer *leaf;
887         struct btrfs_key key;
888         struct btrfs_key found_key;
889         u32 new_size = sizeof(*item);
890         u64 refs;
891         int ret;
892
893         leaf = path->nodes[0];
894         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
895
896         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
897         ei0 = btrfs_item_ptr(leaf, path->slots[0],
898                              struct btrfs_extent_item_v0);
899         refs = btrfs_extent_refs_v0(leaf, ei0);
900
901         if (owner == (u64)-1) {
902                 while (1) {
903                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
904                                 ret = btrfs_next_leaf(root, path);
905                                 if (ret < 0)
906                                         return ret;
907                                 BUG_ON(ret > 0);
908                                 leaf = path->nodes[0];
909                         }
910                         btrfs_item_key_to_cpu(leaf, &found_key,
911                                               path->slots[0]);
912                         BUG_ON(key.objectid != found_key.objectid);
913                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
914                                 path->slots[0]++;
915                                 continue;
916                         }
917                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
918                                               struct btrfs_extent_ref_v0);
919                         owner = btrfs_ref_objectid_v0(leaf, ref0);
920                         break;
921                 }
922         }
923         btrfs_release_path(root, path);
924
925         if (owner < BTRFS_FIRST_FREE_OBJECTID)
926                 new_size += sizeof(*bi);
927
928         new_size -= sizeof(*ei0);
929         ret = btrfs_search_slot(trans, root, &key, path,
930                                 new_size + extra_size, 1);
931         if (ret < 0)
932                 return ret;
933         BUG_ON(ret);
934
935         ret = btrfs_extend_item(trans, root, path, new_size);
936         BUG_ON(ret);
937
938         leaf = path->nodes[0];
939         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
940         btrfs_set_extent_refs(leaf, item, refs);
941         /* FIXME: get real generation */
942         btrfs_set_extent_generation(leaf, item, 0);
943         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
944                 btrfs_set_extent_flags(leaf, item,
945                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
946                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
947                 bi = (struct btrfs_tree_block_info *)(item + 1);
948                 /* FIXME: get first key of the block */
949                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
950                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
951         } else {
952                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
953         }
954         btrfs_mark_buffer_dirty(leaf);
955         return 0;
956 }
957 #endif
958
959 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
960 {
961         u32 high_crc = ~(u32)0;
962         u32 low_crc = ~(u32)0;
963         __le64 lenum;
964
965         lenum = cpu_to_le64(root_objectid);
966         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
967         lenum = cpu_to_le64(owner);
968         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
969         lenum = cpu_to_le64(offset);
970         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
971
972         return ((u64)high_crc << 31) ^ (u64)low_crc;
973 }
974
975 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
976                                      struct btrfs_extent_data_ref *ref)
977 {
978         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
979                                     btrfs_extent_data_ref_objectid(leaf, ref),
980                                     btrfs_extent_data_ref_offset(leaf, ref));
981 }
982
983 static int match_extent_data_ref(struct extent_buffer *leaf,
984                                  struct btrfs_extent_data_ref *ref,
985                                  u64 root_objectid, u64 owner, u64 offset)
986 {
987         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
988             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
989             btrfs_extent_data_ref_offset(leaf, ref) != offset)
990                 return 0;
991         return 1;
992 }
993
994 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
995                                            struct btrfs_root *root,
996                                            struct btrfs_path *path,
997                                            u64 bytenr, u64 parent,
998                                            u64 root_objectid,
999                                            u64 owner, u64 offset)
1000 {
1001         struct btrfs_key key;
1002         struct btrfs_extent_data_ref *ref;
1003         struct extent_buffer *leaf;
1004         u32 nritems;
1005         int ret;
1006         int recow;
1007         int err = -ENOENT;
1008
1009         key.objectid = bytenr;
1010         if (parent) {
1011                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1012                 key.offset = parent;
1013         } else {
1014                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1015                 key.offset = hash_extent_data_ref(root_objectid,
1016                                                   owner, offset);
1017         }
1018 again:
1019         recow = 0;
1020         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1021         if (ret < 0) {
1022                 err = ret;
1023                 goto fail;
1024         }
1025
1026         if (parent) {
1027                 if (!ret)
1028                         return 0;
1029 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1030                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1031                 btrfs_release_path(root, path);
1032                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1033                 if (ret < 0) {
1034                         err = ret;
1035                         goto fail;
1036                 }
1037                 if (!ret)
1038                         return 0;
1039 #endif
1040                 goto fail;
1041         }
1042
1043         leaf = path->nodes[0];
1044         nritems = btrfs_header_nritems(leaf);
1045         while (1) {
1046                 if (path->slots[0] >= nritems) {
1047                         ret = btrfs_next_leaf(root, path);
1048                         if (ret < 0)
1049                                 err = ret;
1050                         if (ret)
1051                                 goto fail;
1052
1053                         leaf = path->nodes[0];
1054                         nritems = btrfs_header_nritems(leaf);
1055                         recow = 1;
1056                 }
1057
1058                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1059                 if (key.objectid != bytenr ||
1060                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1061                         goto fail;
1062
1063                 ref = btrfs_item_ptr(leaf, path->slots[0],
1064                                      struct btrfs_extent_data_ref);
1065
1066                 if (match_extent_data_ref(leaf, ref, root_objectid,
1067                                           owner, offset)) {
1068                         if (recow) {
1069                                 btrfs_release_path(root, path);
1070                                 goto again;
1071                         }
1072                         err = 0;
1073                         break;
1074                 }
1075                 path->slots[0]++;
1076         }
1077 fail:
1078         return err;
1079 }
1080
1081 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1082                                            struct btrfs_root *root,
1083                                            struct btrfs_path *path,
1084                                            u64 bytenr, u64 parent,
1085                                            u64 root_objectid, u64 owner,
1086                                            u64 offset, int refs_to_add)
1087 {
1088         struct btrfs_key key;
1089         struct extent_buffer *leaf;
1090         u32 size;
1091         u32 num_refs;
1092         int ret;
1093
1094         key.objectid = bytenr;
1095         if (parent) {
1096                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1097                 key.offset = parent;
1098                 size = sizeof(struct btrfs_shared_data_ref);
1099         } else {
1100                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1101                 key.offset = hash_extent_data_ref(root_objectid,
1102                                                   owner, offset);
1103                 size = sizeof(struct btrfs_extent_data_ref);
1104         }
1105
1106         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1107         if (ret && ret != -EEXIST)
1108                 goto fail;
1109
1110         leaf = path->nodes[0];
1111         if (parent) {
1112                 struct btrfs_shared_data_ref *ref;
1113                 ref = btrfs_item_ptr(leaf, path->slots[0],
1114                                      struct btrfs_shared_data_ref);
1115                 if (ret == 0) {
1116                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1117                 } else {
1118                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1119                         num_refs += refs_to_add;
1120                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1121                 }
1122         } else {
1123                 struct btrfs_extent_data_ref *ref;
1124                 while (ret == -EEXIST) {
1125                         ref = btrfs_item_ptr(leaf, path->slots[0],
1126                                              struct btrfs_extent_data_ref);
1127                         if (match_extent_data_ref(leaf, ref, root_objectid,
1128                                                   owner, offset))
1129                                 break;
1130                         btrfs_release_path(root, path);
1131                         key.offset++;
1132                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1133                                                       size);
1134                         if (ret && ret != -EEXIST)
1135                                 goto fail;
1136
1137                         leaf = path->nodes[0];
1138                 }
1139                 ref = btrfs_item_ptr(leaf, path->slots[0],
1140                                      struct btrfs_extent_data_ref);
1141                 if (ret == 0) {
1142                         btrfs_set_extent_data_ref_root(leaf, ref,
1143                                                        root_objectid);
1144                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1145                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1146                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1147                 } else {
1148                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1149                         num_refs += refs_to_add;
1150                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1151                 }
1152         }
1153         btrfs_mark_buffer_dirty(leaf);
1154         ret = 0;
1155 fail:
1156         btrfs_release_path(root, path);
1157         return ret;
1158 }
1159
1160 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1161                                            struct btrfs_root *root,
1162                                            struct btrfs_path *path,
1163                                            int refs_to_drop)
1164 {
1165         struct btrfs_key key;
1166         struct btrfs_extent_data_ref *ref1 = NULL;
1167         struct btrfs_shared_data_ref *ref2 = NULL;
1168         struct extent_buffer *leaf;
1169         u32 num_refs = 0;
1170         int ret = 0;
1171
1172         leaf = path->nodes[0];
1173         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1174
1175         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1176                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1177                                       struct btrfs_extent_data_ref);
1178                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1179         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1180                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1181                                       struct btrfs_shared_data_ref);
1182                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1183 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1184         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1185                 struct btrfs_extent_ref_v0 *ref0;
1186                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1187                                       struct btrfs_extent_ref_v0);
1188                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1189 #endif
1190         } else {
1191                 BUG();
1192         }
1193
1194         BUG_ON(num_refs < refs_to_drop);
1195         num_refs -= refs_to_drop;
1196
1197         if (num_refs == 0) {
1198                 ret = btrfs_del_item(trans, root, path);
1199         } else {
1200                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1201                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1202                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1203                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1204 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1205                 else {
1206                         struct btrfs_extent_ref_v0 *ref0;
1207                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1208                                         struct btrfs_extent_ref_v0);
1209                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1210                 }
1211 #endif
1212                 btrfs_mark_buffer_dirty(leaf);
1213         }
1214         return ret;
1215 }
1216
1217 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
1218                                           struct btrfs_path *path,
1219                                           struct btrfs_extent_inline_ref *iref)
1220 {
1221         struct btrfs_key key;
1222         struct extent_buffer *leaf;
1223         struct btrfs_extent_data_ref *ref1;
1224         struct btrfs_shared_data_ref *ref2;
1225         u32 num_refs = 0;
1226
1227         leaf = path->nodes[0];
1228         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1229         if (iref) {
1230                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1231                     BTRFS_EXTENT_DATA_REF_KEY) {
1232                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1233                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1234                 } else {
1235                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1236                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1237                 }
1238         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1239                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1240                                       struct btrfs_extent_data_ref);
1241                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1242         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1243                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1244                                       struct btrfs_shared_data_ref);
1245                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1246 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1247         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1248                 struct btrfs_extent_ref_v0 *ref0;
1249                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1250                                       struct btrfs_extent_ref_v0);
1251                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1252 #endif
1253         } else {
1254                 WARN_ON(1);
1255         }
1256         return num_refs;
1257 }
1258
1259 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1260                                           struct btrfs_root *root,
1261                                           struct btrfs_path *path,
1262                                           u64 bytenr, u64 parent,
1263                                           u64 root_objectid)
1264 {
1265         struct btrfs_key key;
1266         int ret;
1267
1268         key.objectid = bytenr;
1269         if (parent) {
1270                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1271                 key.offset = parent;
1272         } else {
1273                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1274                 key.offset = root_objectid;
1275         }
1276
1277         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1278         if (ret > 0)
1279                 ret = -ENOENT;
1280 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1281         if (ret == -ENOENT && parent) {
1282                 btrfs_release_path(root, path);
1283                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1284                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1285                 if (ret > 0)
1286                         ret = -ENOENT;
1287         }
1288 #endif
1289         return ret;
1290 }
1291
1292 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1293                                           struct btrfs_root *root,
1294                                           struct btrfs_path *path,
1295                                           u64 bytenr, u64 parent,
1296                                           u64 root_objectid)
1297 {
1298         struct btrfs_key key;
1299         int ret;
1300
1301         key.objectid = bytenr;
1302         if (parent) {
1303                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1304                 key.offset = parent;
1305         } else {
1306                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1307                 key.offset = root_objectid;
1308         }
1309
1310         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1311         btrfs_release_path(root, path);
1312         return ret;
1313 }
1314
1315 static inline int extent_ref_type(u64 parent, u64 owner)
1316 {
1317         int type;
1318         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1319                 if (parent > 0)
1320                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1321                 else
1322                         type = BTRFS_TREE_BLOCK_REF_KEY;
1323         } else {
1324                 if (parent > 0)
1325                         type = BTRFS_SHARED_DATA_REF_KEY;
1326                 else
1327                         type = BTRFS_EXTENT_DATA_REF_KEY;
1328         }
1329         return type;
1330 }
1331
1332 static int find_next_key(struct btrfs_path *path, int level,
1333                          struct btrfs_key *key)
1334
1335 {
1336         for (; level < BTRFS_MAX_LEVEL; level++) {
1337                 if (!path->nodes[level])
1338                         break;
1339                 if (path->slots[level] + 1 >=
1340                     btrfs_header_nritems(path->nodes[level]))
1341                         continue;
1342                 if (level == 0)
1343                         btrfs_item_key_to_cpu(path->nodes[level], key,
1344                                               path->slots[level] + 1);
1345                 else
1346                         btrfs_node_key_to_cpu(path->nodes[level], key,
1347                                               path->slots[level] + 1);
1348                 return 0;
1349         }
1350         return 1;
1351 }
1352
1353 /*
1354  * look for inline back ref. if back ref is found, *ref_ret is set
1355  * to the address of inline back ref, and 0 is returned.
1356  *
1357  * if back ref isn't found, *ref_ret is set to the address where it
1358  * should be inserted, and -ENOENT is returned.
1359  *
1360  * if insert is true and there are too many inline back refs, the path
1361  * points to the extent item, and -EAGAIN is returned.
1362  *
1363  * NOTE: inline back refs are ordered in the same way that back ref
1364  *       items in the tree are ordered.
1365  */
1366 static noinline_for_stack
1367 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1368                                  struct btrfs_root *root,
1369                                  struct btrfs_path *path,
1370                                  struct btrfs_extent_inline_ref **ref_ret,
1371                                  u64 bytenr, u64 num_bytes,
1372                                  u64 parent, u64 root_objectid,
1373                                  u64 owner, u64 offset, int insert)
1374 {
1375         struct btrfs_key key;
1376         struct extent_buffer *leaf;
1377         struct btrfs_extent_item *ei;
1378         struct btrfs_extent_inline_ref *iref;
1379         u64 flags;
1380         u64 item_size;
1381         unsigned long ptr;
1382         unsigned long end;
1383         int extra_size;
1384         int type;
1385         int want;
1386         int ret;
1387         int err = 0;
1388
1389         key.objectid = bytenr;
1390         key.type = BTRFS_EXTENT_ITEM_KEY;
1391         key.offset = num_bytes;
1392
1393         want = extent_ref_type(parent, owner);
1394         if (insert) {
1395                 extra_size = btrfs_extent_inline_ref_size(want);
1396                 path->keep_locks = 1;
1397         } else
1398                 extra_size = -1;
1399         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1400         if (ret < 0) {
1401                 err = ret;
1402                 goto out;
1403         }
1404         BUG_ON(ret);
1405
1406         leaf = path->nodes[0];
1407         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1408 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1409         if (item_size < sizeof(*ei)) {
1410                 if (!insert) {
1411                         err = -ENOENT;
1412                         goto out;
1413                 }
1414                 ret = convert_extent_item_v0(trans, root, path, owner,
1415                                              extra_size);
1416                 if (ret < 0) {
1417                         err = ret;
1418                         goto out;
1419                 }
1420                 leaf = path->nodes[0];
1421                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1422         }
1423 #endif
1424         BUG_ON(item_size < sizeof(*ei));
1425
1426         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1427         flags = btrfs_extent_flags(leaf, ei);
1428
1429         ptr = (unsigned long)(ei + 1);
1430         end = (unsigned long)ei + item_size;
1431
1432         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1433                 ptr += sizeof(struct btrfs_tree_block_info);
1434                 BUG_ON(ptr > end);
1435         } else {
1436                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
1437         }
1438
1439         err = -ENOENT;
1440         while (1) {
1441                 if (ptr >= end) {
1442                         WARN_ON(ptr > end);
1443                         break;
1444                 }
1445                 iref = (struct btrfs_extent_inline_ref *)ptr;
1446                 type = btrfs_extent_inline_ref_type(leaf, iref);
1447                 if (want < type)
1448                         break;
1449                 if (want > type) {
1450                         ptr += btrfs_extent_inline_ref_size(type);
1451                         continue;
1452                 }
1453
1454                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1455                         struct btrfs_extent_data_ref *dref;
1456                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1457                         if (match_extent_data_ref(leaf, dref, root_objectid,
1458                                                   owner, offset)) {
1459                                 err = 0;
1460                                 break;
1461                         }
1462                         if (hash_extent_data_ref_item(leaf, dref) <
1463                             hash_extent_data_ref(root_objectid, owner, offset))
1464                                 break;
1465                 } else {
1466                         u64 ref_offset;
1467                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1468                         if (parent > 0) {
1469                                 if (parent == ref_offset) {
1470                                         err = 0;
1471                                         break;
1472                                 }
1473                                 if (ref_offset < parent)
1474                                         break;
1475                         } else {
1476                                 if (root_objectid == ref_offset) {
1477                                         err = 0;
1478                                         break;
1479                                 }
1480                                 if (ref_offset < root_objectid)
1481                                         break;
1482                         }
1483                 }
1484                 ptr += btrfs_extent_inline_ref_size(type);
1485         }
1486         if (err == -ENOENT && insert) {
1487                 if (item_size + extra_size >=
1488                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1489                         err = -EAGAIN;
1490                         goto out;
1491                 }
1492                 /*
1493                  * To add new inline back ref, we have to make sure
1494                  * there is no corresponding back ref item.
1495                  * For simplicity, we just do not add new inline back
1496                  * ref if there is any kind of item for this block
1497                  */
1498                 if (find_next_key(path, 0, &key) == 0 &&
1499                     key.objectid == bytenr &&
1500                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1501                         err = -EAGAIN;
1502                         goto out;
1503                 }
1504         }
1505         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1506 out:
1507         if (insert) {
1508                 path->keep_locks = 0;
1509                 btrfs_unlock_up_safe(path, 1);
1510         }
1511         return err;
1512 }
1513
1514 /*
1515  * helper to add new inline back ref
1516  */
1517 static noinline_for_stack
1518 int setup_inline_extent_backref(struct btrfs_trans_handle *trans,
1519                                 struct btrfs_root *root,
1520                                 struct btrfs_path *path,
1521                                 struct btrfs_extent_inline_ref *iref,
1522                                 u64 parent, u64 root_objectid,
1523                                 u64 owner, u64 offset, int refs_to_add,
1524                                 struct btrfs_delayed_extent_op *extent_op)
1525 {
1526         struct extent_buffer *leaf;
1527         struct btrfs_extent_item *ei;
1528         unsigned long ptr;
1529         unsigned long end;
1530         unsigned long item_offset;
1531         u64 refs;
1532         int size;
1533         int type;
1534         int ret;
1535
1536         leaf = path->nodes[0];
1537         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1538         item_offset = (unsigned long)iref - (unsigned long)ei;
1539
1540         type = extent_ref_type(parent, owner);
1541         size = btrfs_extent_inline_ref_size(type);
1542
1543         ret = btrfs_extend_item(trans, root, path, size);
1544         BUG_ON(ret);
1545
1546         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1547         refs = btrfs_extent_refs(leaf, ei);
1548         refs += refs_to_add;
1549         btrfs_set_extent_refs(leaf, ei, refs);
1550         if (extent_op)
1551                 __run_delayed_extent_op(extent_op, leaf, ei);
1552
1553         ptr = (unsigned long)ei + item_offset;
1554         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1555         if (ptr < end - size)
1556                 memmove_extent_buffer(leaf, ptr + size, ptr,
1557                                       end - size - ptr);
1558
1559         iref = (struct btrfs_extent_inline_ref *)ptr;
1560         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1561         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1562                 struct btrfs_extent_data_ref *dref;
1563                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1564                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1565                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1566                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1567                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1568         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1569                 struct btrfs_shared_data_ref *sref;
1570                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1571                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1572                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1573         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1574                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1575         } else {
1576                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1577         }
1578         btrfs_mark_buffer_dirty(leaf);
1579         return 0;
1580 }
1581
1582 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1583                                  struct btrfs_root *root,
1584                                  struct btrfs_path *path,
1585                                  struct btrfs_extent_inline_ref **ref_ret,
1586                                  u64 bytenr, u64 num_bytes, u64 parent,
1587                                  u64 root_objectid, u64 owner, u64 offset)
1588 {
1589         int ret;
1590
1591         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1592                                            bytenr, num_bytes, parent,
1593                                            root_objectid, owner, offset, 0);
1594         if (ret != -ENOENT)
1595                 return ret;
1596
1597         btrfs_release_path(root, path);
1598         *ref_ret = NULL;
1599
1600         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1601                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1602                                             root_objectid);
1603         } else {
1604                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1605                                              root_objectid, owner, offset);
1606         }
1607         return ret;
1608 }
1609
1610 /*
1611  * helper to update/remove inline back ref
1612  */
1613 static noinline_for_stack
1614 int update_inline_extent_backref(struct btrfs_trans_handle *trans,
1615                                  struct btrfs_root *root,
1616                                  struct btrfs_path *path,
1617                                  struct btrfs_extent_inline_ref *iref,
1618                                  int refs_to_mod,
1619                                  struct btrfs_delayed_extent_op *extent_op)
1620 {
1621         struct extent_buffer *leaf;
1622         struct btrfs_extent_item *ei;
1623         struct btrfs_extent_data_ref *dref = NULL;
1624         struct btrfs_shared_data_ref *sref = NULL;
1625         unsigned long ptr;
1626         unsigned long end;
1627         u32 item_size;
1628         int size;
1629         int type;
1630         int ret;
1631         u64 refs;
1632
1633         leaf = path->nodes[0];
1634         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1635         refs = btrfs_extent_refs(leaf, ei);
1636         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1637         refs += refs_to_mod;
1638         btrfs_set_extent_refs(leaf, ei, refs);
1639         if (extent_op)
1640                 __run_delayed_extent_op(extent_op, leaf, ei);
1641
1642         type = btrfs_extent_inline_ref_type(leaf, iref);
1643
1644         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1645                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1646                 refs = btrfs_extent_data_ref_count(leaf, dref);
1647         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1648                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1649                 refs = btrfs_shared_data_ref_count(leaf, sref);
1650         } else {
1651                 refs = 1;
1652                 BUG_ON(refs_to_mod != -1);
1653         }
1654
1655         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1656         refs += refs_to_mod;
1657
1658         if (refs > 0) {
1659                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1660                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1661                 else
1662                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1663         } else {
1664                 size =  btrfs_extent_inline_ref_size(type);
1665                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1666                 ptr = (unsigned long)iref;
1667                 end = (unsigned long)ei + item_size;
1668                 if (ptr + size < end)
1669                         memmove_extent_buffer(leaf, ptr, ptr + size,
1670                                               end - ptr - size);
1671                 item_size -= size;
1672                 ret = btrfs_truncate_item(trans, root, path, item_size, 1);
1673                 BUG_ON(ret);
1674         }
1675         btrfs_mark_buffer_dirty(leaf);
1676         return 0;
1677 }
1678
1679 static noinline_for_stack
1680 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1681                                  struct btrfs_root *root,
1682                                  struct btrfs_path *path,
1683                                  u64 bytenr, u64 num_bytes, u64 parent,
1684                                  u64 root_objectid, u64 owner,
1685                                  u64 offset, int refs_to_add,
1686                                  struct btrfs_delayed_extent_op *extent_op)
1687 {
1688         struct btrfs_extent_inline_ref *iref;
1689         int ret;
1690
1691         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1692                                            bytenr, num_bytes, parent,
1693                                            root_objectid, owner, offset, 1);
1694         if (ret == 0) {
1695                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1696                 ret = update_inline_extent_backref(trans, root, path, iref,
1697                                                    refs_to_add, extent_op);
1698         } else if (ret == -ENOENT) {
1699                 ret = setup_inline_extent_backref(trans, root, path, iref,
1700                                                   parent, root_objectid,
1701                                                   owner, offset, refs_to_add,
1702                                                   extent_op);
1703         }
1704         return ret;
1705 }
1706
1707 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1708                                  struct btrfs_root *root,
1709                                  struct btrfs_path *path,
1710                                  u64 bytenr, u64 parent, u64 root_objectid,
1711                                  u64 owner, u64 offset, int refs_to_add)
1712 {
1713         int ret;
1714         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1715                 BUG_ON(refs_to_add != 1);
1716                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1717                                             parent, root_objectid);
1718         } else {
1719                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1720                                              parent, root_objectid,
1721                                              owner, offset, refs_to_add);
1722         }
1723         return ret;
1724 }
1725
1726 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1727                                  struct btrfs_root *root,
1728                                  struct btrfs_path *path,
1729                                  struct btrfs_extent_inline_ref *iref,
1730                                  int refs_to_drop, int is_data)
1731 {
1732         int ret;
1733
1734         BUG_ON(!is_data && refs_to_drop != 1);
1735         if (iref) {
1736                 ret = update_inline_extent_backref(trans, root, path, iref,
1737                                                    -refs_to_drop, NULL);
1738         } else if (is_data) {
1739                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1740         } else {
1741                 ret = btrfs_del_item(trans, root, path);
1742         }
1743         return ret;
1744 }
1745
1746 static void btrfs_issue_discard(struct block_device *bdev,
1747                                 u64 start, u64 len)
1748 {
1749         blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_KERNEL,
1750                         BLKDEV_IFL_WAIT | BLKDEV_IFL_BARRIER);
1751 }
1752
1753 static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1754                                 u64 num_bytes)
1755 {
1756         int ret;
1757         u64 map_length = num_bytes;
1758         struct btrfs_multi_bio *multi = NULL;
1759
1760         if (!btrfs_test_opt(root, DISCARD))
1761                 return 0;
1762
1763         /* Tell the block device(s) that the sectors can be discarded */
1764         ret = btrfs_map_block(&root->fs_info->mapping_tree, READ,
1765                               bytenr, &map_length, &multi, 0);
1766         if (!ret) {
1767                 struct btrfs_bio_stripe *stripe = multi->stripes;
1768                 int i;
1769
1770                 if (map_length > num_bytes)
1771                         map_length = num_bytes;
1772
1773                 for (i = 0; i < multi->num_stripes; i++, stripe++) {
1774                         btrfs_issue_discard(stripe->dev->bdev,
1775                                             stripe->physical,
1776                                             map_length);
1777                 }
1778                 kfree(multi);
1779         }
1780
1781         return ret;
1782 }
1783
1784 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1785                          struct btrfs_root *root,
1786                          u64 bytenr, u64 num_bytes, u64 parent,
1787                          u64 root_objectid, u64 owner, u64 offset)
1788 {
1789         int ret;
1790         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
1791                root_objectid == BTRFS_TREE_LOG_OBJECTID);
1792
1793         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1794                 ret = btrfs_add_delayed_tree_ref(trans, bytenr, num_bytes,
1795                                         parent, root_objectid, (int)owner,
1796                                         BTRFS_ADD_DELAYED_REF, NULL);
1797         } else {
1798                 ret = btrfs_add_delayed_data_ref(trans, bytenr, num_bytes,
1799                                         parent, root_objectid, owner, offset,
1800                                         BTRFS_ADD_DELAYED_REF, NULL);
1801         }
1802         return ret;
1803 }
1804
1805 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1806                                   struct btrfs_root *root,
1807                                   u64 bytenr, u64 num_bytes,
1808                                   u64 parent, u64 root_objectid,
1809                                   u64 owner, u64 offset, int refs_to_add,
1810                                   struct btrfs_delayed_extent_op *extent_op)
1811 {
1812         struct btrfs_path *path;
1813         struct extent_buffer *leaf;
1814         struct btrfs_extent_item *item;
1815         u64 refs;
1816         int ret;
1817         int err = 0;
1818
1819         path = btrfs_alloc_path();
1820         if (!path)
1821                 return -ENOMEM;
1822
1823         path->reada = 1;
1824         path->leave_spinning = 1;
1825         /* this will setup the path even if it fails to insert the back ref */
1826         ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
1827                                            path, bytenr, num_bytes, parent,
1828                                            root_objectid, owner, offset,
1829                                            refs_to_add, extent_op);
1830         if (ret == 0)
1831                 goto out;
1832
1833         if (ret != -EAGAIN) {
1834                 err = ret;
1835                 goto out;
1836         }
1837
1838         leaf = path->nodes[0];
1839         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1840         refs = btrfs_extent_refs(leaf, item);
1841         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
1842         if (extent_op)
1843                 __run_delayed_extent_op(extent_op, leaf, item);
1844
1845         btrfs_mark_buffer_dirty(leaf);
1846         btrfs_release_path(root->fs_info->extent_root, path);
1847
1848         path->reada = 1;
1849         path->leave_spinning = 1;
1850
1851         /* now insert the actual backref */
1852         ret = insert_extent_backref(trans, root->fs_info->extent_root,
1853                                     path, bytenr, parent, root_objectid,
1854                                     owner, offset, refs_to_add);
1855         BUG_ON(ret);
1856 out:
1857         btrfs_free_path(path);
1858         return err;
1859 }
1860
1861 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
1862                                 struct btrfs_root *root,
1863                                 struct btrfs_delayed_ref_node *node,
1864                                 struct btrfs_delayed_extent_op *extent_op,
1865                                 int insert_reserved)
1866 {
1867         int ret = 0;
1868         struct btrfs_delayed_data_ref *ref;
1869         struct btrfs_key ins;
1870         u64 parent = 0;
1871         u64 ref_root = 0;
1872         u64 flags = 0;
1873
1874         ins.objectid = node->bytenr;
1875         ins.offset = node->num_bytes;
1876         ins.type = BTRFS_EXTENT_ITEM_KEY;
1877
1878         ref = btrfs_delayed_node_to_data_ref(node);
1879         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
1880                 parent = ref->parent;
1881         else
1882                 ref_root = ref->root;
1883
1884         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1885                 if (extent_op) {
1886                         BUG_ON(extent_op->update_key);
1887                         flags |= extent_op->flags_to_set;
1888                 }
1889                 ret = alloc_reserved_file_extent(trans, root,
1890                                                  parent, ref_root, flags,
1891                                                  ref->objectid, ref->offset,
1892                                                  &ins, node->ref_mod);
1893         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
1894                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
1895                                              node->num_bytes, parent,
1896                                              ref_root, ref->objectid,
1897                                              ref->offset, node->ref_mod,
1898                                              extent_op);
1899         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
1900                 ret = __btrfs_free_extent(trans, root, node->bytenr,
1901                                           node->num_bytes, parent,
1902                                           ref_root, ref->objectid,
1903                                           ref->offset, node->ref_mod,
1904                                           extent_op);
1905         } else {
1906                 BUG();
1907         }
1908         return ret;
1909 }
1910
1911 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
1912                                     struct extent_buffer *leaf,
1913                                     struct btrfs_extent_item *ei)
1914 {
1915         u64 flags = btrfs_extent_flags(leaf, ei);
1916         if (extent_op->update_flags) {
1917                 flags |= extent_op->flags_to_set;
1918                 btrfs_set_extent_flags(leaf, ei, flags);
1919         }
1920
1921         if (extent_op->update_key) {
1922                 struct btrfs_tree_block_info *bi;
1923                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
1924                 bi = (struct btrfs_tree_block_info *)(ei + 1);
1925                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
1926         }
1927 }
1928
1929 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
1930                                  struct btrfs_root *root,
1931                                  struct btrfs_delayed_ref_node *node,
1932                                  struct btrfs_delayed_extent_op *extent_op)
1933 {
1934         struct btrfs_key key;
1935         struct btrfs_path *path;
1936         struct btrfs_extent_item *ei;
1937         struct extent_buffer *leaf;
1938         u32 item_size;
1939         int ret;
1940         int err = 0;
1941
1942         path = btrfs_alloc_path();
1943         if (!path)
1944                 return -ENOMEM;
1945
1946         key.objectid = node->bytenr;
1947         key.type = BTRFS_EXTENT_ITEM_KEY;
1948         key.offset = node->num_bytes;
1949
1950         path->reada = 1;
1951         path->leave_spinning = 1;
1952         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
1953                                 path, 0, 1);
1954         if (ret < 0) {
1955                 err = ret;
1956                 goto out;
1957         }
1958         if (ret > 0) {
1959                 err = -EIO;
1960                 goto out;
1961         }
1962
1963         leaf = path->nodes[0];
1964         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1965 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1966         if (item_size < sizeof(*ei)) {
1967                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
1968                                              path, (u64)-1, 0);
1969                 if (ret < 0) {
1970                         err = ret;
1971                         goto out;
1972                 }
1973                 leaf = path->nodes[0];
1974                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1975         }
1976 #endif
1977         BUG_ON(item_size < sizeof(*ei));
1978         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1979         __run_delayed_extent_op(extent_op, leaf, ei);
1980
1981         btrfs_mark_buffer_dirty(leaf);
1982 out:
1983         btrfs_free_path(path);
1984         return err;
1985 }
1986
1987 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
1988                                 struct btrfs_root *root,
1989                                 struct btrfs_delayed_ref_node *node,
1990                                 struct btrfs_delayed_extent_op *extent_op,
1991                                 int insert_reserved)
1992 {
1993         int ret = 0;
1994         struct btrfs_delayed_tree_ref *ref;
1995         struct btrfs_key ins;
1996         u64 parent = 0;
1997         u64 ref_root = 0;
1998
1999         ins.objectid = node->bytenr;
2000         ins.offset = node->num_bytes;
2001         ins.type = BTRFS_EXTENT_ITEM_KEY;
2002
2003         ref = btrfs_delayed_node_to_tree_ref(node);
2004         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2005                 parent = ref->parent;
2006         else
2007                 ref_root = ref->root;
2008
2009         BUG_ON(node->ref_mod != 1);
2010         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2011                 BUG_ON(!extent_op || !extent_op->update_flags ||
2012                        !extent_op->update_key);
2013                 ret = alloc_reserved_tree_block(trans, root,
2014                                                 parent, ref_root,
2015                                                 extent_op->flags_to_set,
2016                                                 &extent_op->key,
2017                                                 ref->level, &ins);
2018         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2019                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2020                                              node->num_bytes, parent, ref_root,
2021                                              ref->level, 0, 1, extent_op);
2022         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2023                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2024                                           node->num_bytes, parent, ref_root,
2025                                           ref->level, 0, 1, extent_op);
2026         } else {
2027                 BUG();
2028         }
2029         return ret;
2030 }
2031
2032 /* helper function to actually process a single delayed ref entry */
2033 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2034                                struct btrfs_root *root,
2035                                struct btrfs_delayed_ref_node *node,
2036                                struct btrfs_delayed_extent_op *extent_op,
2037                                int insert_reserved)
2038 {
2039         int ret;
2040         if (btrfs_delayed_ref_is_head(node)) {
2041                 struct btrfs_delayed_ref_head *head;
2042                 /*
2043                  * we've hit the end of the chain and we were supposed
2044                  * to insert this extent into the tree.  But, it got
2045                  * deleted before we ever needed to insert it, so all
2046                  * we have to do is clean up the accounting
2047                  */
2048                 BUG_ON(extent_op);
2049                 head = btrfs_delayed_node_to_head(node);
2050                 if (insert_reserved) {
2051                         btrfs_pin_extent(root, node->bytenr,
2052                                          node->num_bytes, 1);
2053                         if (head->is_data) {
2054                                 ret = btrfs_del_csums(trans, root,
2055                                                       node->bytenr,
2056                                                       node->num_bytes);
2057                                 BUG_ON(ret);
2058                         }
2059                 }
2060                 mutex_unlock(&head->mutex);
2061                 return 0;
2062         }
2063
2064         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2065             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2066                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2067                                            insert_reserved);
2068         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2069                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2070                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2071                                            insert_reserved);
2072         else
2073                 BUG();
2074         return ret;
2075 }
2076
2077 static noinline struct btrfs_delayed_ref_node *
2078 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2079 {
2080         struct rb_node *node;
2081         struct btrfs_delayed_ref_node *ref;
2082         int action = BTRFS_ADD_DELAYED_REF;
2083 again:
2084         /*
2085          * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
2086          * this prevents ref count from going down to zero when
2087          * there still are pending delayed ref.
2088          */
2089         node = rb_prev(&head->node.rb_node);
2090         while (1) {
2091                 if (!node)
2092                         break;
2093                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
2094                                 rb_node);
2095                 if (ref->bytenr != head->node.bytenr)
2096                         break;
2097                 if (ref->action == action)
2098                         return ref;
2099                 node = rb_prev(node);
2100         }
2101         if (action == BTRFS_ADD_DELAYED_REF) {
2102                 action = BTRFS_DROP_DELAYED_REF;
2103                 goto again;
2104         }
2105         return NULL;
2106 }
2107
2108 static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
2109                                        struct btrfs_root *root,
2110                                        struct list_head *cluster)
2111 {
2112         struct btrfs_delayed_ref_root *delayed_refs;
2113         struct btrfs_delayed_ref_node *ref;
2114         struct btrfs_delayed_ref_head *locked_ref = NULL;
2115         struct btrfs_delayed_extent_op *extent_op;
2116         int ret;
2117         int count = 0;
2118         int must_insert_reserved = 0;
2119
2120         delayed_refs = &trans->transaction->delayed_refs;
2121         while (1) {
2122                 if (!locked_ref) {
2123                         /* pick a new head ref from the cluster list */
2124                         if (list_empty(cluster))
2125                                 break;
2126
2127                         locked_ref = list_entry(cluster->next,
2128                                      struct btrfs_delayed_ref_head, cluster);
2129
2130                         /* grab the lock that says we are going to process
2131                          * all the refs for this head */
2132                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2133
2134                         /*
2135                          * we may have dropped the spin lock to get the head
2136                          * mutex lock, and that might have given someone else
2137                          * time to free the head.  If that's true, it has been
2138                          * removed from our list and we can move on.
2139                          */
2140                         if (ret == -EAGAIN) {
2141                                 locked_ref = NULL;
2142                                 count++;
2143                                 continue;
2144                         }
2145                 }
2146
2147                 /*
2148                  * record the must insert reserved flag before we
2149                  * drop the spin lock.
2150                  */
2151                 must_insert_reserved = locked_ref->must_insert_reserved;
2152                 locked_ref->must_insert_reserved = 0;
2153
2154                 extent_op = locked_ref->extent_op;
2155                 locked_ref->extent_op = NULL;
2156
2157                 /*
2158                  * locked_ref is the head node, so we have to go one
2159                  * node back for any delayed ref updates
2160                  */
2161                 ref = select_delayed_ref(locked_ref);
2162                 if (!ref) {
2163                         /* All delayed refs have been processed, Go ahead
2164                          * and send the head node to run_one_delayed_ref,
2165                          * so that any accounting fixes can happen
2166                          */
2167                         ref = &locked_ref->node;
2168
2169                         if (extent_op && must_insert_reserved) {
2170                                 kfree(extent_op);
2171                                 extent_op = NULL;
2172                         }
2173
2174                         if (extent_op) {
2175                                 spin_unlock(&delayed_refs->lock);
2176
2177                                 ret = run_delayed_extent_op(trans, root,
2178                                                             ref, extent_op);
2179                                 BUG_ON(ret);
2180                                 kfree(extent_op);
2181
2182                                 cond_resched();
2183                                 spin_lock(&delayed_refs->lock);
2184                                 continue;
2185                         }
2186
2187                         list_del_init(&locked_ref->cluster);
2188                         locked_ref = NULL;
2189                 }
2190
2191                 ref->in_tree = 0;
2192                 rb_erase(&ref->rb_node, &delayed_refs->root);
2193                 delayed_refs->num_entries--;
2194
2195                 spin_unlock(&delayed_refs->lock);
2196
2197                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2198                                           must_insert_reserved);
2199                 BUG_ON(ret);
2200
2201                 btrfs_put_delayed_ref(ref);
2202                 kfree(extent_op);
2203                 count++;
2204
2205                 cond_resched();
2206                 spin_lock(&delayed_refs->lock);
2207         }
2208         return count;
2209 }
2210
2211 /*
2212  * this starts processing the delayed reference count updates and
2213  * extent insertions we have queued up so far.  count can be
2214  * 0, which means to process everything in the tree at the start
2215  * of the run (but not newly added entries), or it can be some target
2216  * number you'd like to process.
2217  */
2218 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2219                            struct btrfs_root *root, unsigned long count)
2220 {
2221         struct rb_node *node;
2222         struct btrfs_delayed_ref_root *delayed_refs;
2223         struct btrfs_delayed_ref_node *ref;
2224         struct list_head cluster;
2225         int ret;
2226         int run_all = count == (unsigned long)-1;
2227         int run_most = 0;
2228
2229         if (root == root->fs_info->extent_root)
2230                 root = root->fs_info->tree_root;
2231
2232         delayed_refs = &trans->transaction->delayed_refs;
2233         INIT_LIST_HEAD(&cluster);
2234 again:
2235         spin_lock(&delayed_refs->lock);
2236         if (count == 0) {
2237                 count = delayed_refs->num_entries * 2;
2238                 run_most = 1;
2239         }
2240         while (1) {
2241                 if (!(run_all || run_most) &&
2242                     delayed_refs->num_heads_ready < 64)
2243                         break;
2244
2245                 /*
2246                  * go find something we can process in the rbtree.  We start at
2247                  * the beginning of the tree, and then build a cluster
2248                  * of refs to process starting at the first one we are able to
2249                  * lock
2250                  */
2251                 ret = btrfs_find_ref_cluster(trans, &cluster,
2252                                              delayed_refs->run_delayed_start);
2253                 if (ret)
2254                         break;
2255
2256                 ret = run_clustered_refs(trans, root, &cluster);
2257                 BUG_ON(ret < 0);
2258
2259                 count -= min_t(unsigned long, ret, count);
2260
2261                 if (count == 0)
2262                         break;
2263         }
2264
2265         if (run_all) {
2266                 node = rb_first(&delayed_refs->root);
2267                 if (!node)
2268                         goto out;
2269                 count = (unsigned long)-1;
2270
2271                 while (node) {
2272                         ref = rb_entry(node, struct btrfs_delayed_ref_node,
2273                                        rb_node);
2274                         if (btrfs_delayed_ref_is_head(ref)) {
2275                                 struct btrfs_delayed_ref_head *head;
2276
2277                                 head = btrfs_delayed_node_to_head(ref);
2278                                 atomic_inc(&ref->refs);
2279
2280                                 spin_unlock(&delayed_refs->lock);
2281                                 mutex_lock(&head->mutex);
2282                                 mutex_unlock(&head->mutex);
2283
2284                                 btrfs_put_delayed_ref(ref);
2285                                 cond_resched();
2286                                 goto again;
2287                         }
2288                         node = rb_next(node);
2289                 }
2290                 spin_unlock(&delayed_refs->lock);
2291                 schedule_timeout(1);
2292                 goto again;
2293         }
2294 out:
2295         spin_unlock(&delayed_refs->lock);
2296         return 0;
2297 }
2298
2299 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2300                                 struct btrfs_root *root,
2301                                 u64 bytenr, u64 num_bytes, u64 flags,
2302                                 int is_data)
2303 {
2304         struct btrfs_delayed_extent_op *extent_op;
2305         int ret;
2306
2307         extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2308         if (!extent_op)
2309                 return -ENOMEM;
2310
2311         extent_op->flags_to_set = flags;
2312         extent_op->update_flags = 1;
2313         extent_op->update_key = 0;
2314         extent_op->is_data = is_data ? 1 : 0;
2315
2316         ret = btrfs_add_delayed_extent_op(trans, bytenr, num_bytes, extent_op);
2317         if (ret)
2318                 kfree(extent_op);
2319         return ret;
2320 }
2321
2322 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2323                                       struct btrfs_root *root,
2324                                       struct btrfs_path *path,
2325                                       u64 objectid, u64 offset, u64 bytenr)
2326 {
2327         struct btrfs_delayed_ref_head *head;
2328         struct btrfs_delayed_ref_node *ref;
2329         struct btrfs_delayed_data_ref *data_ref;
2330         struct btrfs_delayed_ref_root *delayed_refs;
2331         struct rb_node *node;
2332         int ret = 0;
2333
2334         ret = -ENOENT;
2335         delayed_refs = &trans->transaction->delayed_refs;
2336         spin_lock(&delayed_refs->lock);
2337         head = btrfs_find_delayed_ref_head(trans, bytenr);
2338         if (!head)
2339                 goto out;
2340
2341         if (!mutex_trylock(&head->mutex)) {
2342                 atomic_inc(&head->node.refs);
2343                 spin_unlock(&delayed_refs->lock);
2344
2345                 btrfs_release_path(root->fs_info->extent_root, path);
2346
2347                 mutex_lock(&head->mutex);
2348                 mutex_unlock(&head->mutex);
2349                 btrfs_put_delayed_ref(&head->node);
2350                 return -EAGAIN;
2351         }
2352
2353         node = rb_prev(&head->node.rb_node);
2354         if (!node)
2355                 goto out_unlock;
2356
2357         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2358
2359         if (ref->bytenr != bytenr)
2360                 goto out_unlock;
2361
2362         ret = 1;
2363         if (ref->type != BTRFS_EXTENT_DATA_REF_KEY)
2364                 goto out_unlock;
2365
2366         data_ref = btrfs_delayed_node_to_data_ref(ref);
2367
2368         node = rb_prev(node);
2369         if (node) {
2370                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2371                 if (ref->bytenr == bytenr)
2372                         goto out_unlock;
2373         }
2374
2375         if (data_ref->root != root->root_key.objectid ||
2376             data_ref->objectid != objectid || data_ref->offset != offset)
2377                 goto out_unlock;
2378
2379         ret = 0;
2380 out_unlock:
2381         mutex_unlock(&head->mutex);
2382 out:
2383         spin_unlock(&delayed_refs->lock);
2384         return ret;
2385 }
2386
2387 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2388                                         struct btrfs_root *root,
2389                                         struct btrfs_path *path,
2390                                         u64 objectid, u64 offset, u64 bytenr)
2391 {
2392         struct btrfs_root *extent_root = root->fs_info->extent_root;
2393         struct extent_buffer *leaf;
2394         struct btrfs_extent_data_ref *ref;
2395         struct btrfs_extent_inline_ref *iref;
2396         struct btrfs_extent_item *ei;
2397         struct btrfs_key key;
2398         u32 item_size;
2399         int ret;
2400
2401         key.objectid = bytenr;
2402         key.offset = (u64)-1;
2403         key.type = BTRFS_EXTENT_ITEM_KEY;
2404
2405         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2406         if (ret < 0)
2407                 goto out;
2408         BUG_ON(ret == 0);
2409
2410         ret = -ENOENT;
2411         if (path->slots[0] == 0)
2412                 goto out;
2413
2414         path->slots[0]--;
2415         leaf = path->nodes[0];
2416         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2417
2418         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2419                 goto out;
2420
2421         ret = 1;
2422         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2423 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2424         if (item_size < sizeof(*ei)) {
2425                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2426                 goto out;
2427         }
2428 #endif
2429         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2430
2431         if (item_size != sizeof(*ei) +
2432             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2433                 goto out;
2434
2435         if (btrfs_extent_generation(leaf, ei) <=
2436             btrfs_root_last_snapshot(&root->root_item))
2437                 goto out;
2438
2439         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2440         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2441             BTRFS_EXTENT_DATA_REF_KEY)
2442                 goto out;
2443
2444         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2445         if (btrfs_extent_refs(leaf, ei) !=
2446             btrfs_extent_data_ref_count(leaf, ref) ||
2447             btrfs_extent_data_ref_root(leaf, ref) !=
2448             root->root_key.objectid ||
2449             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2450             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2451                 goto out;
2452
2453         ret = 0;
2454 out:
2455         return ret;
2456 }
2457
2458 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
2459                           struct btrfs_root *root,
2460                           u64 objectid, u64 offset, u64 bytenr)
2461 {
2462         struct btrfs_path *path;
2463         int ret;
2464         int ret2;
2465
2466         path = btrfs_alloc_path();
2467         if (!path)
2468                 return -ENOENT;
2469
2470         do {
2471                 ret = check_committed_ref(trans, root, path, objectid,
2472                                           offset, bytenr);
2473                 if (ret && ret != -ENOENT)
2474                         goto out;
2475
2476                 ret2 = check_delayed_ref(trans, root, path, objectid,
2477                                          offset, bytenr);
2478         } while (ret2 == -EAGAIN);
2479
2480         if (ret2 && ret2 != -ENOENT) {
2481                 ret = ret2;
2482                 goto out;
2483         }
2484
2485         if (ret != -ENOENT || ret2 != -ENOENT)
2486                 ret = 0;
2487 out:
2488         btrfs_free_path(path);
2489         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
2490                 WARN_ON(ret > 0);
2491         return ret;
2492 }
2493
2494 #if 0
2495 int btrfs_cache_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2496                     struct extent_buffer *buf, u32 nr_extents)
2497 {
2498         struct btrfs_key key;
2499         struct btrfs_file_extent_item *fi;
2500         u64 root_gen;
2501         u32 nritems;
2502         int i;
2503         int level;
2504         int ret = 0;
2505         int shared = 0;
2506
2507         if (!root->ref_cows)
2508                 return 0;
2509
2510         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
2511                 shared = 0;
2512                 root_gen = root->root_key.offset;
2513         } else {
2514                 shared = 1;
2515                 root_gen = trans->transid - 1;
2516         }
2517
2518         level = btrfs_header_level(buf);
2519         nritems = btrfs_header_nritems(buf);
2520
2521         if (level == 0) {
2522                 struct btrfs_leaf_ref *ref;
2523                 struct btrfs_extent_info *info;
2524
2525                 ref = btrfs_alloc_leaf_ref(root, nr_extents);
2526                 if (!ref) {
2527                         ret = -ENOMEM;
2528                         goto out;
2529                 }
2530
2531                 ref->root_gen = root_gen;
2532                 ref->bytenr = buf->start;
2533                 ref->owner = btrfs_header_owner(buf);
2534                 ref->generation = btrfs_header_generation(buf);
2535                 ref->nritems = nr_extents;
2536                 info = ref->extents;
2537
2538                 for (i = 0; nr_extents > 0 && i < nritems; i++) {
2539                         u64 disk_bytenr;
2540                         btrfs_item_key_to_cpu(buf, &key, i);
2541                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2542                                 continue;
2543                         fi = btrfs_item_ptr(buf, i,
2544                                             struct btrfs_file_extent_item);
2545                         if (btrfs_file_extent_type(buf, fi) ==
2546                             BTRFS_FILE_EXTENT_INLINE)
2547                                 continue;
2548                         disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2549                         if (disk_bytenr == 0)
2550                                 continue;
2551
2552                         info->bytenr = disk_bytenr;
2553                         info->num_bytes =
2554                                 btrfs_file_extent_disk_num_bytes(buf, fi);
2555                         info->objectid = key.objectid;
2556                         info->offset = key.offset;
2557                         info++;
2558                 }
2559
2560                 ret = btrfs_add_leaf_ref(root, ref, shared);
2561                 if (ret == -EEXIST && shared) {
2562                         struct btrfs_leaf_ref *old;
2563                         old = btrfs_lookup_leaf_ref(root, ref->bytenr);
2564                         BUG_ON(!old);
2565                         btrfs_remove_leaf_ref(root, old);
2566                         btrfs_free_leaf_ref(root, old);
2567                         ret = btrfs_add_leaf_ref(root, ref, shared);
2568                 }
2569                 WARN_ON(ret);
2570                 btrfs_free_leaf_ref(root, ref);
2571         }
2572 out:
2573         return ret;
2574 }
2575
2576 /* when a block goes through cow, we update the reference counts of
2577  * everything that block points to.  The internal pointers of the block
2578  * can be in just about any order, and it is likely to have clusters of
2579  * things that are close together and clusters of things that are not.
2580  *
2581  * To help reduce the seeks that come with updating all of these reference
2582  * counts, sort them by byte number before actual updates are done.
2583  *
2584  * struct refsort is used to match byte number to slot in the btree block.
2585  * we sort based on the byte number and then use the slot to actually
2586  * find the item.
2587  *
2588  * struct refsort is smaller than strcut btrfs_item and smaller than
2589  * struct btrfs_key_ptr.  Since we're currently limited to the page size
2590  * for a btree block, there's no way for a kmalloc of refsorts for a
2591  * single node to be bigger than a page.
2592  */
2593 struct refsort {
2594         u64 bytenr;
2595         u32 slot;
2596 };
2597
2598 /*
2599  * for passing into sort()
2600  */
2601 static int refsort_cmp(const void *a_void, const void *b_void)
2602 {
2603         const struct refsort *a = a_void;
2604         const struct refsort *b = b_void;
2605
2606         if (a->bytenr < b->bytenr)
2607                 return -1;
2608         if (a->bytenr > b->bytenr)
2609                 return 1;
2610         return 0;
2611 }
2612 #endif
2613
2614 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
2615                            struct btrfs_root *root,
2616                            struct extent_buffer *buf,
2617                            int full_backref, int inc)
2618 {
2619         u64 bytenr;
2620         u64 num_bytes;
2621         u64 parent;
2622         u64 ref_root;
2623         u32 nritems;
2624         struct btrfs_key key;
2625         struct btrfs_file_extent_item *fi;
2626         int i;
2627         int level;
2628         int ret = 0;
2629         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
2630                             u64, u64, u64, u64, u64, u64);
2631
2632         ref_root = btrfs_header_owner(buf);
2633         nritems = btrfs_header_nritems(buf);
2634         level = btrfs_header_level(buf);
2635
2636         if (!root->ref_cows && level == 0)
2637                 return 0;
2638
2639         if (inc)
2640                 process_func = btrfs_inc_extent_ref;
2641         else
2642                 process_func = btrfs_free_extent;
2643
2644         if (full_backref)
2645                 parent = buf->start;
2646         else
2647                 parent = 0;
2648
2649         for (i = 0; i < nritems; i++) {
2650                 if (level == 0) {
2651                         btrfs_item_key_to_cpu(buf, &key, i);
2652                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2653                                 continue;
2654                         fi = btrfs_item_ptr(buf, i,
2655                                             struct btrfs_file_extent_item);
2656                         if (btrfs_file_extent_type(buf, fi) ==
2657                             BTRFS_FILE_EXTENT_INLINE)
2658                                 continue;
2659                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2660                         if (bytenr == 0)
2661                                 continue;
2662
2663                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
2664                         key.offset -= btrfs_file_extent_offset(buf, fi);
2665                         ret = process_func(trans, root, bytenr, num_bytes,
2666                                            parent, ref_root, key.objectid,
2667                                            key.offset);
2668                         if (ret)
2669                                 goto fail;
2670                 } else {
2671                         bytenr = btrfs_node_blockptr(buf, i);
2672                         num_bytes = btrfs_level_size(root, level - 1);
2673                         ret = process_func(trans, root, bytenr, num_bytes,
2674                                            parent, ref_root, level - 1, 0);
2675                         if (ret)
2676                                 goto fail;
2677                 }
2678         }
2679         return 0;
2680 fail:
2681         BUG();
2682         return ret;
2683 }
2684
2685 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2686                   struct extent_buffer *buf, int full_backref)
2687 {
2688         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
2689 }
2690
2691 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2692                   struct extent_buffer *buf, int full_backref)
2693 {
2694         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
2695 }
2696
2697 static int write_one_cache_group(struct btrfs_trans_handle *trans,
2698                                  struct btrfs_root *root,
2699                                  struct btrfs_path *path,
2700                                  struct btrfs_block_group_cache *cache)
2701 {
2702         int ret;
2703         struct btrfs_root *extent_root = root->fs_info->extent_root;
2704         unsigned long bi;
2705         struct extent_buffer *leaf;
2706
2707         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
2708         if (ret < 0)
2709                 goto fail;
2710         BUG_ON(ret);
2711
2712         leaf = path->nodes[0];
2713         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
2714         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
2715         btrfs_mark_buffer_dirty(leaf);
2716         btrfs_release_path(extent_root, path);
2717 fail:
2718         if (ret)
2719                 return ret;
2720         return 0;
2721
2722 }
2723
2724 static struct btrfs_block_group_cache *
2725 next_block_group(struct btrfs_root *root,
2726                  struct btrfs_block_group_cache *cache)
2727 {
2728         struct rb_node *node;
2729         spin_lock(&root->fs_info->block_group_cache_lock);
2730         node = rb_next(&cache->cache_node);
2731         btrfs_put_block_group(cache);
2732         if (node) {
2733                 cache = rb_entry(node, struct btrfs_block_group_cache,
2734                                  cache_node);
2735                 btrfs_get_block_group(cache);
2736         } else
2737                 cache = NULL;
2738         spin_unlock(&root->fs_info->block_group_cache_lock);
2739         return cache;
2740 }
2741
2742 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
2743                             struct btrfs_trans_handle *trans,
2744                             struct btrfs_path *path)
2745 {
2746         struct btrfs_root *root = block_group->fs_info->tree_root;
2747         struct inode *inode = NULL;
2748         u64 alloc_hint = 0;
2749         int dcs = BTRFS_DC_ERROR;
2750         int num_pages = 0;
2751         int retries = 0;
2752         int ret = 0;
2753
2754         /*
2755          * If this block group is smaller than 100 megs don't bother caching the
2756          * block group.
2757          */
2758         if (block_group->key.offset < (100 * 1024 * 1024)) {
2759                 spin_lock(&block_group->lock);
2760                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
2761                 spin_unlock(&block_group->lock);
2762                 return 0;
2763         }
2764
2765 again:
2766         inode = lookup_free_space_inode(root, block_group, path);
2767         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
2768                 ret = PTR_ERR(inode);
2769                 btrfs_release_path(root, path);
2770                 goto out;
2771         }
2772
2773         if (IS_ERR(inode)) {
2774                 BUG_ON(retries);
2775                 retries++;
2776
2777                 if (block_group->ro)
2778                         goto out_free;
2779
2780                 ret = create_free_space_inode(root, trans, block_group, path);
2781                 if (ret)
2782                         goto out_free;
2783                 goto again;
2784         }
2785
2786         /*
2787          * We want to set the generation to 0, that way if anything goes wrong
2788          * from here on out we know not to trust this cache when we load up next
2789          * time.
2790          */
2791         BTRFS_I(inode)->generation = 0;
2792         ret = btrfs_update_inode(trans, root, inode);
2793         WARN_ON(ret);
2794
2795         if (i_size_read(inode) > 0) {
2796                 ret = btrfs_truncate_free_space_cache(root, trans, path,
2797                                                       inode);
2798                 if (ret)
2799                         goto out_put;
2800         }
2801
2802         spin_lock(&block_group->lock);
2803         if (block_group->cached != BTRFS_CACHE_FINISHED) {
2804                 /* We're not cached, don't bother trying to write stuff out */
2805                 dcs = BTRFS_DC_WRITTEN;
2806                 spin_unlock(&block_group->lock);
2807                 goto out_put;
2808         }
2809         spin_unlock(&block_group->lock);
2810
2811         num_pages = (int)div64_u64(block_group->key.offset, 1024 * 1024 * 1024);
2812         if (!num_pages)
2813                 num_pages = 1;
2814
2815         /*
2816          * Just to make absolutely sure we have enough space, we're going to
2817          * preallocate 12 pages worth of space for each block group.  In
2818          * practice we ought to use at most 8, but we need extra space so we can
2819          * add our header and have a terminator between the extents and the
2820          * bitmaps.
2821          */
2822         num_pages *= 16;
2823         num_pages *= PAGE_CACHE_SIZE;
2824
2825         ret = btrfs_check_data_free_space(inode, num_pages);
2826         if (ret)
2827                 goto out_put;
2828
2829         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
2830                                               num_pages, num_pages,
2831                                               &alloc_hint);
2832         if (!ret)
2833                 dcs = BTRFS_DC_SETUP;
2834         btrfs_free_reserved_data_space(inode, num_pages);
2835 out_put:
2836         iput(inode);
2837 out_free:
2838         btrfs_release_path(root, path);
2839 out:
2840         spin_lock(&block_group->lock);
2841         block_group->disk_cache_state = dcs;
2842         spin_unlock(&block_group->lock);
2843
2844         return ret;
2845 }
2846
2847 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
2848                                    struct btrfs_root *root)
2849 {
2850         struct btrfs_block_group_cache *cache;
2851         int err = 0;
2852         struct btrfs_path *path;
2853         u64 last = 0;
2854
2855         path = btrfs_alloc_path();
2856         if (!path)
2857                 return -ENOMEM;
2858
2859 again:
2860         while (1) {
2861                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2862                 while (cache) {
2863                         if (cache->disk_cache_state == BTRFS_DC_CLEAR)
2864                                 break;
2865                         cache = next_block_group(root, cache);
2866                 }
2867                 if (!cache) {
2868                         if (last == 0)
2869                                 break;
2870                         last = 0;
2871                         continue;
2872                 }
2873                 err = cache_save_setup(cache, trans, path);
2874                 last = cache->key.objectid + cache->key.offset;
2875                 btrfs_put_block_group(cache);
2876         }
2877
2878         while (1) {
2879                 if (last == 0) {
2880                         err = btrfs_run_delayed_refs(trans, root,
2881                                                      (unsigned long)-1);
2882                         BUG_ON(err);
2883                 }
2884
2885                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2886                 while (cache) {
2887                         if (cache->disk_cache_state == BTRFS_DC_CLEAR) {
2888                                 btrfs_put_block_group(cache);
2889                                 goto again;
2890                         }
2891
2892                         if (cache->dirty)
2893                                 break;
2894                         cache = next_block_group(root, cache);
2895                 }
2896                 if (!cache) {
2897                         if (last == 0)
2898                                 break;
2899                         last = 0;
2900                         continue;
2901                 }
2902
2903                 if (cache->disk_cache_state == BTRFS_DC_SETUP)
2904                         cache->disk_cache_state = BTRFS_DC_NEED_WRITE;
2905                 cache->dirty = 0;
2906                 last = cache->key.objectid + cache->key.offset;
2907
2908                 err = write_one_cache_group(trans, root, path, cache);
2909                 BUG_ON(err);
2910                 btrfs_put_block_group(cache);
2911         }
2912
2913         while (1) {
2914                 /*
2915                  * I don't think this is needed since we're just marking our
2916                  * preallocated extent as written, but just in case it can't
2917                  * hurt.
2918                  */
2919                 if (last == 0) {
2920                         err = btrfs_run_delayed_refs(trans, root,
2921                                                      (unsigned long)-1);
2922                         BUG_ON(err);
2923                 }
2924
2925                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2926                 while (cache) {
2927                         /*
2928                          * Really this shouldn't happen, but it could if we
2929                          * couldn't write the entire preallocated extent and
2930                          * splitting the extent resulted in a new block.
2931                          */
2932                         if (cache->dirty) {
2933                                 btrfs_put_block_group(cache);
2934                                 goto again;
2935                         }
2936                         if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
2937                                 break;
2938                         cache = next_block_group(root, cache);
2939                 }
2940                 if (!cache) {
2941                         if (last == 0)
2942                                 break;
2943                         last = 0;
2944                         continue;
2945                 }
2946
2947                 btrfs_write_out_cache(root, trans, cache, path);
2948
2949                 /*
2950                  * If we didn't have an error then the cache state is still
2951                  * NEED_WRITE, so we can set it to WRITTEN.
2952                  */
2953                 if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
2954                         cache->disk_cache_state = BTRFS_DC_WRITTEN;
2955                 last = cache->key.objectid + cache->key.offset;
2956                 btrfs_put_block_group(cache);
2957         }
2958
2959         btrfs_free_path(path);
2960         return 0;
2961 }
2962
2963 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
2964 {
2965         struct btrfs_block_group_cache *block_group;
2966         int readonly = 0;
2967
2968         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
2969         if (!block_group || block_group->ro)
2970                 readonly = 1;
2971         if (block_group)
2972                 btrfs_put_block_group(block_group);
2973         return readonly;
2974 }
2975
2976 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
2977                              u64 total_bytes, u64 bytes_used,
2978                              struct btrfs_space_info **space_info)
2979 {
2980         struct btrfs_space_info *found;
2981         int i;
2982         int factor;
2983
2984         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
2985                      BTRFS_BLOCK_GROUP_RAID10))
2986                 factor = 2;
2987         else
2988                 factor = 1;
2989
2990         found = __find_space_info(info, flags);
2991         if (found) {
2992                 spin_lock(&found->lock);
2993                 found->total_bytes += total_bytes;
2994                 found->disk_total += total_bytes * factor;
2995                 found->bytes_used += bytes_used;
2996                 found->disk_used += bytes_used * factor;
2997                 found->full = 0;
2998                 spin_unlock(&found->lock);
2999                 *space_info = found;
3000                 return 0;
3001         }
3002         found = kzalloc(sizeof(*found), GFP_NOFS);
3003         if (!found)
3004                 return -ENOMEM;
3005
3006         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3007                 INIT_LIST_HEAD(&found->block_groups[i]);
3008         init_rwsem(&found->groups_sem);
3009         spin_lock_init(&found->lock);
3010         found->flags = flags & (BTRFS_BLOCK_GROUP_DATA |
3011                                 BTRFS_BLOCK_GROUP_SYSTEM |
3012                                 BTRFS_BLOCK_GROUP_METADATA);
3013         found->total_bytes = total_bytes;
3014         found->disk_total = total_bytes * factor;
3015         found->bytes_used = bytes_used;
3016         found->disk_used = bytes_used * factor;
3017         found->bytes_pinned = 0;
3018         found->bytes_reserved = 0;
3019         found->bytes_readonly = 0;
3020         found->bytes_may_use = 0;
3021         found->full = 0;
3022         found->force_alloc = 0;
3023         *space_info = found;
3024         list_add_rcu(&found->list, &info->space_info);
3025         atomic_set(&found->caching_threads, 0);
3026         return 0;
3027 }
3028
3029 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3030 {
3031         u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
3032                                    BTRFS_BLOCK_GROUP_RAID1 |
3033                                    BTRFS_BLOCK_GROUP_RAID10 |
3034                                    BTRFS_BLOCK_GROUP_DUP);
3035         if (extra_flags) {
3036                 if (flags & BTRFS_BLOCK_GROUP_DATA)
3037                         fs_info->avail_data_alloc_bits |= extra_flags;
3038                 if (flags & BTRFS_BLOCK_GROUP_METADATA)
3039                         fs_info->avail_metadata_alloc_bits |= extra_flags;
3040                 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3041                         fs_info->avail_system_alloc_bits |= extra_flags;
3042         }
3043 }
3044
3045 u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3046 {
3047         /*
3048          * we add in the count of missing devices because we want
3049          * to make sure that any RAID levels on a degraded FS
3050          * continue to be honored.
3051          */
3052         u64 num_devices = root->fs_info->fs_devices->rw_devices +
3053                 root->fs_info->fs_devices->missing_devices;
3054
3055         if (num_devices == 1)
3056                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
3057         if (num_devices < 4)
3058                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
3059
3060         if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
3061             (flags & (BTRFS_BLOCK_GROUP_RAID1 |
3062                       BTRFS_BLOCK_GROUP_RAID10))) {
3063                 flags &= ~BTRFS_BLOCK_GROUP_DUP;
3064         }
3065
3066         if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
3067             (flags & BTRFS_BLOCK_GROUP_RAID10)) {
3068                 flags &= ~BTRFS_BLOCK_GROUP_RAID1;
3069         }
3070
3071         if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
3072             ((flags & BTRFS_BLOCK_GROUP_RAID1) |
3073              (flags & BTRFS_BLOCK_GROUP_RAID10) |
3074              (flags & BTRFS_BLOCK_GROUP_DUP)))
3075                 flags &= ~BTRFS_BLOCK_GROUP_RAID0;
3076         return flags;
3077 }
3078
3079 static u64 get_alloc_profile(struct btrfs_root *root, u64 flags)
3080 {
3081         if (flags & BTRFS_BLOCK_GROUP_DATA)
3082                 flags |= root->fs_info->avail_data_alloc_bits &
3083                          root->fs_info->data_alloc_profile;
3084         else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3085                 flags |= root->fs_info->avail_system_alloc_bits &
3086                          root->fs_info->system_alloc_profile;
3087         else if (flags & BTRFS_BLOCK_GROUP_METADATA)
3088                 flags |= root->fs_info->avail_metadata_alloc_bits &
3089                          root->fs_info->metadata_alloc_profile;
3090         return btrfs_reduce_alloc_profile(root, flags);
3091 }
3092
3093 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3094 {
3095         u64 flags;
3096
3097         if (data)
3098                 flags = BTRFS_BLOCK_GROUP_DATA;
3099         else if (root == root->fs_info->chunk_root)
3100                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3101         else
3102                 flags = BTRFS_BLOCK_GROUP_METADATA;
3103
3104         return get_alloc_profile(root, flags);
3105 }
3106
3107 void btrfs_set_inode_space_info(struct btrfs_root *root, struct inode *inode)
3108 {
3109         BTRFS_I(inode)->space_info = __find_space_info(root->fs_info,
3110                                                        BTRFS_BLOCK_GROUP_DATA);
3111 }
3112
3113 /*
3114  * This will check the space that the inode allocates from to make sure we have
3115  * enough space for bytes.
3116  */
3117 int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
3118 {
3119         struct btrfs_space_info *data_sinfo;
3120         struct btrfs_root *root = BTRFS_I(inode)->root;
3121         u64 used;
3122         int ret = 0, committed = 0, alloc_chunk = 1;
3123
3124         /* make sure bytes are sectorsize aligned */
3125         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3126
3127         if (root == root->fs_info->tree_root) {
3128                 alloc_chunk = 0;
3129                 committed = 1;
3130         }
3131
3132         data_sinfo = BTRFS_I(inode)->space_info;
3133         if (!data_sinfo)
3134                 goto alloc;
3135
3136 again:
3137         /* make sure we have enough space to handle the data first */
3138         spin_lock(&data_sinfo->lock);
3139         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3140                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3141                 data_sinfo->bytes_may_use;
3142
3143         if (used + bytes > data_sinfo->total_bytes) {
3144                 struct btrfs_trans_handle *trans;
3145
3146                 /*
3147                  * if we don't have enough free bytes in this space then we need
3148                  * to alloc a new chunk.
3149                  */
3150                 if (!data_sinfo->full && alloc_chunk) {
3151                         u64 alloc_target;
3152
3153                         data_sinfo->force_alloc = 1;
3154                         spin_unlock(&data_sinfo->lock);
3155 alloc:
3156                         alloc_target = btrfs_get_alloc_profile(root, 1);
3157                         trans = btrfs_join_transaction(root, 1);
3158                         if (IS_ERR(trans))
3159                                 return PTR_ERR(trans);
3160
3161                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3162                                              bytes + 2 * 1024 * 1024,
3163                                              alloc_target, 0);
3164                         btrfs_end_transaction(trans, root);
3165                         if (ret < 0) {
3166                                 if (ret != -ENOSPC)
3167                                         return ret;
3168                                 else
3169                                         goto commit_trans;
3170                         }
3171
3172                         if (!data_sinfo) {
3173                                 btrfs_set_inode_space_info(root, inode);
3174                                 data_sinfo = BTRFS_I(inode)->space_info;
3175                         }
3176                         goto again;
3177                 }
3178                 spin_unlock(&data_sinfo->lock);
3179
3180                 /* commit the current transaction and try again */
3181 commit_trans:
3182                 if (!committed && !root->fs_info->open_ioctl_trans) {
3183                         committed = 1;
3184                         trans = btrfs_join_transaction(root, 1);
3185                         if (IS_ERR(trans))
3186                                 return PTR_ERR(trans);
3187                         ret = btrfs_commit_transaction(trans, root);
3188                         if (ret)
3189                                 return ret;
3190                         goto again;
3191                 }
3192
3193 #if 0 /* I hope we never need this code again, just in case */
3194                 printk(KERN_ERR "no space left, need %llu, %llu bytes_used, "
3195                        "%llu bytes_reserved, " "%llu bytes_pinned, "
3196                        "%llu bytes_readonly, %llu may use %llu total\n",
3197                        (unsigned long long)bytes,
3198                        (unsigned long long)data_sinfo->bytes_used,
3199                        (unsigned long long)data_sinfo->bytes_reserved,
3200                        (unsigned long long)data_sinfo->bytes_pinned,
3201                        (unsigned long long)data_sinfo->bytes_readonly,
3202                        (unsigned long long)data_sinfo->bytes_may_use,
3203                        (unsigned long long)data_sinfo->total_bytes);
3204 #endif
3205                 return -ENOSPC;
3206         }
3207         data_sinfo->bytes_may_use += bytes;
3208         BTRFS_I(inode)->reserved_bytes += bytes;
3209         spin_unlock(&data_sinfo->lock);
3210
3211         return 0;
3212 }
3213
3214 /*
3215  * called when we are clearing an delalloc extent from the
3216  * inode's io_tree or there was an error for whatever reason
3217  * after calling btrfs_check_data_free_space
3218  */
3219 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3220 {
3221         struct btrfs_root *root = BTRFS_I(inode)->root;
3222         struct btrfs_space_info *data_sinfo;
3223
3224         /* make sure bytes are sectorsize aligned */
3225         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3226
3227         data_sinfo = BTRFS_I(inode)->space_info;
3228         spin_lock(&data_sinfo->lock);
3229         data_sinfo->bytes_may_use -= bytes;
3230         BTRFS_I(inode)->reserved_bytes -= bytes;
3231         spin_unlock(&data_sinfo->lock);
3232 }
3233
3234 static void force_metadata_allocation(struct btrfs_fs_info *info)
3235 {
3236         struct list_head *head = &info->space_info;
3237         struct btrfs_space_info *found;
3238
3239         rcu_read_lock();
3240         list_for_each_entry_rcu(found, head, list) {
3241                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3242                         found->force_alloc = 1;
3243         }
3244         rcu_read_unlock();
3245 }
3246
3247 static int should_alloc_chunk(struct btrfs_root *root,
3248                               struct btrfs_space_info *sinfo, u64 alloc_bytes)
3249 {
3250         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
3251         u64 thresh;
3252
3253         if (sinfo->bytes_used + sinfo->bytes_reserved +
3254             alloc_bytes + 256 * 1024 * 1024 < num_bytes)
3255                 return 0;
3256
3257         if (sinfo->bytes_used + sinfo->bytes_reserved +
3258             alloc_bytes < div_factor(num_bytes, 8))
3259                 return 0;
3260
3261         thresh = btrfs_super_total_bytes(&root->fs_info->super_copy);
3262         thresh = max_t(u64, 256 * 1024 * 1024, div_factor_fine(thresh, 5));
3263
3264         if (num_bytes > thresh && sinfo->bytes_used < div_factor(num_bytes, 3))
3265                 return 0;
3266
3267         return 1;
3268 }
3269
3270 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3271                           struct btrfs_root *extent_root, u64 alloc_bytes,
3272                           u64 flags, int force)
3273 {
3274         struct btrfs_space_info *space_info;
3275         struct btrfs_fs_info *fs_info = extent_root->fs_info;
3276         int ret = 0;
3277
3278         mutex_lock(&fs_info->chunk_mutex);
3279
3280         flags = btrfs_reduce_alloc_profile(extent_root, flags);
3281
3282         space_info = __find_space_info(extent_root->fs_info, flags);
3283         if (!space_info) {
3284                 ret = update_space_info(extent_root->fs_info, flags,
3285                                         0, 0, &space_info);
3286                 BUG_ON(ret);
3287         }
3288         BUG_ON(!space_info);
3289
3290         spin_lock(&space_info->lock);
3291         if (space_info->force_alloc)
3292                 force = 1;
3293         if (space_info->full) {
3294                 spin_unlock(&space_info->lock);
3295                 goto out;
3296         }
3297
3298         if (!force && !should_alloc_chunk(extent_root, space_info,
3299                                           alloc_bytes)) {
3300                 spin_unlock(&space_info->lock);
3301                 goto out;
3302         }
3303         spin_unlock(&space_info->lock);
3304
3305         /*
3306          * If we have mixed data/metadata chunks we want to make sure we keep
3307          * allocating mixed chunks instead of individual chunks.
3308          */
3309         if (btrfs_mixed_space_info(space_info))
3310                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3311
3312         /*
3313          * if we're doing a data chunk, go ahead and make sure that
3314          * we keep a reasonable number of metadata chunks allocated in the
3315          * FS as well.
3316          */
3317         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3318                 fs_info->data_chunk_allocations++;
3319                 if (!(fs_info->data_chunk_allocations %
3320                       fs_info->metadata_ratio))
3321                         force_metadata_allocation(fs_info);
3322         }
3323
3324         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3325         spin_lock(&space_info->lock);
3326         if (ret)
3327                 space_info->full = 1;
3328         else
3329                 ret = 1;
3330         space_info->force_alloc = 0;
3331         spin_unlock(&space_info->lock);
3332 out:
3333         mutex_unlock(&extent_root->fs_info->chunk_mutex);
3334         return ret;
3335 }
3336
3337 /*
3338  * shrink metadata reservation for delalloc
3339  */
3340 static int shrink_delalloc(struct btrfs_trans_handle *trans,
3341                            struct btrfs_root *root, u64 to_reclaim, int sync)
3342 {
3343         struct btrfs_block_rsv *block_rsv;
3344         struct btrfs_space_info *space_info;
3345         u64 reserved;
3346         u64 max_reclaim;
3347         u64 reclaimed = 0;
3348         int pause = 1;
3349         int nr_pages = (2 * 1024 * 1024) >> PAGE_CACHE_SHIFT;
3350
3351         block_rsv = &root->fs_info->delalloc_block_rsv;
3352         space_info = block_rsv->space_info;
3353
3354         smp_mb();
3355         reserved = space_info->bytes_reserved;
3356
3357         if (reserved == 0)
3358                 return 0;
3359
3360         max_reclaim = min(reserved, to_reclaim);
3361
3362         while (1) {
3363                 /* have the flusher threads jump in and do some IO */
3364                 smp_mb();
3365                 nr_pages = min_t(unsigned long, nr_pages,
3366                        root->fs_info->delalloc_bytes >> PAGE_CACHE_SHIFT);
3367                 writeback_inodes_sb_nr_if_idle(root->fs_info->sb, nr_pages);
3368
3369                 spin_lock(&space_info->lock);
3370                 if (reserved > space_info->bytes_reserved)
3371                         reclaimed += reserved - space_info->bytes_reserved;
3372                 reserved = space_info->bytes_reserved;
3373                 spin_unlock(&space_info->lock);
3374
3375                 if (reserved == 0 || reclaimed >= max_reclaim)
3376                         break;
3377
3378                 if (trans && trans->transaction->blocked)
3379                         return -EAGAIN;
3380
3381                 __set_current_state(TASK_INTERRUPTIBLE);
3382                 schedule_timeout(pause);
3383                 pause <<= 1;
3384                 if (pause > HZ / 10)
3385                         pause = HZ / 10;
3386
3387         }
3388         return reclaimed >= to_reclaim;
3389 }
3390
3391 /*
3392  * Retries tells us how many times we've called reserve_metadata_bytes.  The
3393  * idea is if this is the first call (retries == 0) then we will add to our
3394  * reserved count if we can't make the allocation in order to hold our place
3395  * while we go and try and free up space.  That way for retries > 1 we don't try
3396  * and add space, we just check to see if the amount of unused space is >= the
3397  * total space, meaning that our reservation is valid.
3398  *
3399  * However if we don't intend to retry this reservation, pass -1 as retries so
3400  * that it short circuits this logic.
3401  */
3402 static int reserve_metadata_bytes(struct btrfs_trans_handle *trans,
3403                                   struct btrfs_root *root,
3404                                   struct btrfs_block_rsv *block_rsv,
3405                                   u64 orig_bytes, int flush)
3406 {
3407         struct btrfs_space_info *space_info = block_rsv->space_info;
3408         u64 unused;
3409         u64 num_bytes = orig_bytes;
3410         int retries = 0;
3411         int ret = 0;
3412         bool reserved = false;
3413         bool committed = false;
3414
3415 again:
3416         ret = -ENOSPC;
3417         if (reserved)
3418                 num_bytes = 0;
3419
3420         spin_lock(&space_info->lock);
3421         unused = space_info->bytes_used + space_info->bytes_reserved +
3422                  space_info->bytes_pinned + space_info->bytes_readonly +
3423                  space_info->bytes_may_use;
3424
3425         /*
3426          * The idea here is that we've not already over-reserved the block group
3427          * then we can go ahead and save our reservation first and then start
3428          * flushing if we need to.  Otherwise if we've already overcommitted
3429          * lets start flushing stuff first and then come back and try to make
3430          * our reservation.
3431          */
3432         if (unused <= space_info->total_bytes) {
3433                 unused = space_info->total_bytes - unused;
3434                 if (unused >= num_bytes) {
3435                         if (!reserved)
3436                                 space_info->bytes_reserved += orig_bytes;
3437                         ret = 0;
3438                 } else {
3439                         /*
3440                          * Ok set num_bytes to orig_bytes since we aren't
3441                          * overocmmitted, this way we only try and reclaim what
3442                          * we need.
3443                          */
3444                         num_bytes = orig_bytes;
3445                 }
3446         } else {
3447                 /*
3448                  * Ok we're over committed, set num_bytes to the overcommitted
3449                  * amount plus the amount of bytes that we need for this
3450                  * reservation.
3451                  */
3452                 num_bytes = unused - space_info->total_bytes +
3453                         (orig_bytes * (retries + 1));
3454         }
3455
3456         /*
3457          * Couldn't make our reservation, save our place so while we're trying
3458          * to reclaim space we can actually use it instead of somebody else
3459          * stealing it from us.
3460          */
3461         if (ret && !reserved) {
3462                 space_info->bytes_reserved += orig_bytes;
3463                 reserved = true;
3464         }
3465
3466         spin_unlock(&space_info->lock);
3467
3468         if (!ret)
3469                 return 0;
3470
3471         if (!flush)
3472                 goto out;
3473
3474         /*
3475          * We do synchronous shrinking since we don't actually unreserve
3476          * metadata until after the IO is completed.
3477          */
3478         ret = shrink_delalloc(trans, root, num_bytes, 1);
3479         if (ret > 0)
3480                 return 0;
3481         else if (ret < 0)
3482                 goto out;
3483
3484         /*
3485          * So if we were overcommitted it's possible that somebody else flushed
3486          * out enough space and we simply didn't have enough space to reclaim,
3487          * so go back around and try again.
3488          */
3489         if (retries < 2) {
3490                 retries++;
3491                 goto again;
3492         }
3493
3494         spin_lock(&space_info->lock);
3495         /*
3496          * Not enough space to be reclaimed, don't bother committing the
3497          * transaction.
3498          */
3499         if (space_info->bytes_pinned < orig_bytes)
3500                 ret = -ENOSPC;
3501         spin_unlock(&space_info->lock);
3502         if (ret)
3503                 goto out;
3504
3505         ret = -EAGAIN;
3506         if (trans || committed)
3507                 goto out;
3508
3509         ret = -ENOSPC;
3510         trans = btrfs_join_transaction(root, 1);
3511         if (IS_ERR(trans))
3512                 goto out;
3513         ret = btrfs_commit_transaction(trans, root);
3514         if (!ret) {
3515                 trans = NULL;
3516                 committed = true;
3517                 goto again;
3518         }
3519
3520 out:
3521         if (reserved) {
3522                 spin_lock(&space_info->lock);
3523                 space_info->bytes_reserved -= orig_bytes;
3524                 spin_unlock(&space_info->lock);
3525         }
3526
3527         return ret;
3528 }
3529
3530 static struct btrfs_block_rsv *get_block_rsv(struct btrfs_trans_handle *trans,
3531                                              struct btrfs_root *root)
3532 {
3533         struct btrfs_block_rsv *block_rsv;
3534         if (root->ref_cows)
3535                 block_rsv = trans->block_rsv;
3536         else
3537                 block_rsv = root->block_rsv;
3538
3539         if (!block_rsv)
3540                 block_rsv = &root->fs_info->empty_block_rsv;
3541
3542         return block_rsv;
3543 }
3544
3545 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
3546                                u64 num_bytes)
3547 {
3548         int ret = -ENOSPC;
3549         spin_lock(&block_rsv->lock);
3550         if (block_rsv->reserved >= num_bytes) {
3551                 block_rsv->reserved -= num_bytes;
3552                 if (block_rsv->reserved < block_rsv->size)
3553                         block_rsv->full = 0;
3554                 ret = 0;
3555         }
3556         spin_unlock(&block_rsv->lock);
3557         return ret;
3558 }
3559
3560 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
3561                                 u64 num_bytes, int update_size)
3562 {
3563         spin_lock(&block_rsv->lock);
3564         block_rsv->reserved += num_bytes;
3565         if (update_size)
3566                 block_rsv->size += num_bytes;
3567         else if (block_rsv->reserved >= block_rsv->size)
3568                 block_rsv->full = 1;
3569         spin_unlock(&block_rsv->lock);
3570 }
3571
3572 void block_rsv_release_bytes(struct btrfs_block_rsv *block_rsv,
3573                              struct btrfs_block_rsv *dest, u64 num_bytes)
3574 {
3575         struct btrfs_space_info *space_info = block_rsv->space_info;
3576
3577         spin_lock(&block_rsv->lock);
3578         if (num_bytes == (u64)-1)
3579                 num_bytes = block_rsv->size;
3580         block_rsv->size -= num_bytes;
3581         if (block_rsv->reserved >= block_rsv->size) {
3582                 num_bytes = block_rsv->reserved - block_rsv->size;
3583                 block_rsv->reserved = block_rsv->size;
3584                 block_rsv->full = 1;
3585         } else {
3586                 num_bytes = 0;
3587         }
3588         spin_unlock(&block_rsv->lock);
3589
3590         if (num_bytes > 0) {
3591                 if (dest) {
3592                         block_rsv_add_bytes(dest, num_bytes, 0);
3593                 } else {
3594                         spin_lock(&space_info->lock);
3595                         space_info->bytes_reserved -= num_bytes;
3596                         spin_unlock(&space_info->lock);
3597                 }
3598         }
3599 }
3600
3601 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
3602                                    struct btrfs_block_rsv *dst, u64 num_bytes)
3603 {
3604         int ret;
3605
3606         ret = block_rsv_use_bytes(src, num_bytes);
3607         if (ret)
3608                 return ret;
3609
3610         block_rsv_add_bytes(dst, num_bytes, 1);
3611         return 0;
3612 }
3613
3614 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv)
3615 {
3616         memset(rsv, 0, sizeof(*rsv));
3617         spin_lock_init(&rsv->lock);
3618         atomic_set(&rsv->usage, 1);
3619         rsv->priority = 6;
3620         INIT_LIST_HEAD(&rsv->list);
3621 }
3622
3623 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root)
3624 {
3625         struct btrfs_block_rsv *block_rsv;
3626         struct btrfs_fs_info *fs_info = root->fs_info;
3627
3628         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
3629         if (!block_rsv)
3630                 return NULL;
3631
3632         btrfs_init_block_rsv(block_rsv);
3633         block_rsv->space_info = __find_space_info(fs_info,
3634                                                   BTRFS_BLOCK_GROUP_METADATA);
3635         return block_rsv;
3636 }
3637
3638 void btrfs_free_block_rsv(struct btrfs_root *root,
3639                           struct btrfs_block_rsv *rsv)
3640 {
3641         if (rsv && atomic_dec_and_test(&rsv->usage)) {
3642                 btrfs_block_rsv_release(root, rsv, (u64)-1);
3643                 if (!rsv->durable)
3644                         kfree(rsv);
3645         }
3646 }
3647
3648 /*
3649  * make the block_rsv struct be able to capture freed space.
3650  * the captured space will re-add to the the block_rsv struct
3651  * after transaction commit
3652  */
3653 void btrfs_add_durable_block_rsv(struct btrfs_fs_info *fs_info,
3654                                  struct btrfs_block_rsv *block_rsv)
3655 {
3656         block_rsv->durable = 1;
3657         mutex_lock(&fs_info->durable_block_rsv_mutex);
3658         list_add_tail(&block_rsv->list, &fs_info->durable_block_rsv_list);
3659         mutex_unlock(&fs_info->durable_block_rsv_mutex);
3660 }
3661
3662 int btrfs_block_rsv_add(struct btrfs_trans_handle *trans,
3663                         struct btrfs_root *root,
3664                         struct btrfs_block_rsv *block_rsv,
3665                         u64 num_bytes)
3666 {
3667         int ret;
3668
3669         if (num_bytes == 0)
3670                 return 0;
3671
3672         ret = reserve_metadata_bytes(trans, root, block_rsv, num_bytes, 1);
3673         if (!ret) {
3674                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
3675                 return 0;
3676         }
3677
3678         return ret;
3679 }
3680
3681 int btrfs_block_rsv_check(struct btrfs_trans_handle *trans,
3682                           struct btrfs_root *root,
3683                           struct btrfs_block_rsv *block_rsv,
3684                           u64 min_reserved, int min_factor)
3685 {
3686         u64 num_bytes = 0;
3687         int commit_trans = 0;
3688         int ret = -ENOSPC;
3689
3690         if (!block_rsv)
3691                 return 0;
3692
3693         spin_lock(&block_rsv->lock);
3694         if (min_factor > 0)
3695                 num_bytes = div_factor(block_rsv->size, min_factor);
3696         if (min_reserved > num_bytes)
3697                 num_bytes = min_reserved;
3698
3699         if (block_rsv->reserved >= num_bytes) {
3700                 ret = 0;
3701         } else {
3702                 num_bytes -= block_rsv->reserved;
3703                 if (block_rsv->durable &&
3704                     block_rsv->freed[0] + block_rsv->freed[1] >= num_bytes)
3705                         commit_trans = 1;
3706         }
3707         spin_unlock(&block_rsv->lock);
3708         if (!ret)
3709                 return 0;
3710
3711         if (block_rsv->refill_used) {
3712                 ret = reserve_metadata_bytes(trans, root, block_rsv,
3713                                              num_bytes, 0);
3714                 if (!ret) {
3715                         block_rsv_add_bytes(block_rsv, num_bytes, 0);
3716                         return 0;
3717                 }
3718         }
3719
3720         if (commit_trans) {
3721                 if (trans)
3722                         return -EAGAIN;
3723
3724                 trans = btrfs_join_transaction(root, 1);
3725                 BUG_ON(IS_ERR(trans));
3726                 ret = btrfs_commit_transaction(trans, root);
3727                 return 0;
3728         }
3729
3730         return -ENOSPC;
3731 }
3732
3733 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
3734                             struct btrfs_block_rsv *dst_rsv,
3735                             u64 num_bytes)
3736 {
3737         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
3738 }
3739
3740 void btrfs_block_rsv_release(struct btrfs_root *root,
3741                              struct btrfs_block_rsv *block_rsv,
3742                              u64 num_bytes)
3743 {
3744         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3745         if (global_rsv->full || global_rsv == block_rsv ||
3746             block_rsv->space_info != global_rsv->space_info)
3747                 global_rsv = NULL;
3748         block_rsv_release_bytes(block_rsv, global_rsv, num_bytes);
3749 }
3750
3751 /*
3752  * helper to calculate size of global block reservation.
3753  * the desired value is sum of space used by extent tree,
3754  * checksum tree and root tree
3755  */
3756 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
3757 {
3758         struct btrfs_space_info *sinfo;
3759         u64 num_bytes;
3760         u64 meta_used;
3761         u64 data_used;
3762         int csum_size = btrfs_super_csum_size(&fs_info->super_copy);
3763 #if 0
3764         /*
3765          * per tree used space accounting can be inaccuracy, so we
3766          * can't rely on it.
3767          */
3768         spin_lock(&fs_info->extent_root->accounting_lock);
3769         num_bytes = btrfs_root_used(&fs_info->extent_root->root_item);
3770         spin_unlock(&fs_info->extent_root->accounting_lock);
3771
3772         spin_lock(&fs_info->csum_root->accounting_lock);
3773         num_bytes += btrfs_root_used(&fs_info->csum_root->root_item);
3774         spin_unlock(&fs_info->csum_root->accounting_lock);
3775
3776         spin_lock(&fs_info->tree_root->accounting_lock);
3777         num_bytes += btrfs_root_used(&fs_info->tree_root->root_item);
3778         spin_unlock(&fs_info->tree_root->accounting_lock);
3779 #endif
3780         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
3781         spin_lock(&sinfo->lock);
3782         data_used = sinfo->bytes_used;
3783         spin_unlock(&sinfo->lock);
3784
3785         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
3786         spin_lock(&sinfo->lock);
3787         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
3788                 data_used = 0;
3789         meta_used = sinfo->bytes_used;
3790         spin_unlock(&sinfo->lock);
3791
3792         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
3793                     csum_size * 2;
3794         num_bytes += div64_u64(data_used + meta_used, 50);
3795
3796         if (num_bytes * 3 > meta_used)
3797                 num_bytes = div64_u64(meta_used, 3);
3798
3799         return ALIGN(num_bytes, fs_info->extent_root->leafsize << 10);
3800 }
3801
3802 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
3803 {
3804         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
3805         struct btrfs_space_info *sinfo = block_rsv->space_info;
3806         u64 num_bytes;
3807
3808         num_bytes = calc_global_metadata_size(fs_info);
3809
3810         spin_lock(&block_rsv->lock);
3811         spin_lock(&sinfo->lock);
3812
3813         block_rsv->size = num_bytes;
3814
3815         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
3816                     sinfo->bytes_reserved + sinfo->bytes_readonly +
3817                     sinfo->bytes_may_use;
3818
3819         if (sinfo->total_bytes > num_bytes) {
3820                 num_bytes = sinfo->total_bytes - num_bytes;
3821                 block_rsv->reserved += num_bytes;
3822                 sinfo->bytes_reserved += num_bytes;
3823         }
3824
3825         if (block_rsv->reserved >= block_rsv->size) {
3826                 num_bytes = block_rsv->reserved - block_rsv->size;
3827                 sinfo->bytes_reserved -= num_bytes;
3828                 block_rsv->reserved = block_rsv->size;
3829                 block_rsv->full = 1;
3830         }
3831 #if 0
3832         printk(KERN_INFO"global block rsv size %llu reserved %llu\n",
3833                 block_rsv->size, block_rsv->reserved);
3834 #endif
3835         spin_unlock(&sinfo->lock);
3836         spin_unlock(&block_rsv->lock);
3837 }
3838
3839 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
3840 {
3841         struct btrfs_space_info *space_info;
3842
3843         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
3844         fs_info->chunk_block_rsv.space_info = space_info;
3845         fs_info->chunk_block_rsv.priority = 10;
3846
3847         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
3848         fs_info->global_block_rsv.space_info = space_info;
3849         fs_info->global_block_rsv.priority = 10;
3850         fs_info->global_block_rsv.refill_used = 1;
3851         fs_info->delalloc_block_rsv.space_info = space_info;
3852         fs_info->trans_block_rsv.space_info = space_info;
3853         fs_info->empty_block_rsv.space_info = space_info;
3854         fs_info->empty_block_rsv.priority = 10;
3855
3856         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
3857         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
3858         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
3859         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
3860         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
3861
3862         btrfs_add_durable_block_rsv(fs_info, &fs_info->global_block_rsv);
3863
3864         btrfs_add_durable_block_rsv(fs_info, &fs_info->delalloc_block_rsv);
3865
3866         update_global_block_rsv(fs_info);
3867 }
3868
3869 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
3870 {
3871         block_rsv_release_bytes(&fs_info->global_block_rsv, NULL, (u64)-1);
3872         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
3873         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
3874         WARN_ON(fs_info->trans_block_rsv.size > 0);
3875         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
3876         WARN_ON(fs_info->chunk_block_rsv.size > 0);
3877         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
3878 }
3879
3880 static u64 calc_trans_metadata_size(struct btrfs_root *root, int num_items)
3881 {
3882         return (root->leafsize + root->nodesize * (BTRFS_MAX_LEVEL - 1)) *
3883                 3 * num_items;
3884 }
3885
3886 int btrfs_trans_reserve_metadata(struct btrfs_trans_handle *trans,
3887                                  struct btrfs_root *root,
3888                                  int num_items)
3889 {
3890         u64 num_bytes;
3891         int ret;
3892
3893         if (num_items == 0 || root->fs_info->chunk_root == root)
3894                 return 0;
3895
3896         num_bytes = calc_trans_metadata_size(root, num_items);
3897         ret = btrfs_block_rsv_add(trans, root, &root->fs_info->trans_block_rsv,
3898                                   num_bytes);
3899         if (!ret) {
3900                 trans->bytes_reserved += num_bytes;
3901                 trans->block_rsv = &root->fs_info->trans_block_rsv;
3902         }
3903         return ret;
3904 }
3905
3906 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
3907                                   struct btrfs_root *root)
3908 {
3909         if (!trans->bytes_reserved)
3910                 return;
3911
3912         BUG_ON(trans->block_rsv != &root->fs_info->trans_block_rsv);
3913         btrfs_block_rsv_release(root, trans->block_rsv,
3914                                 trans->bytes_reserved);
3915         trans->bytes_reserved = 0;
3916 }
3917
3918 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
3919                                   struct inode *inode)
3920 {
3921         struct btrfs_root *root = BTRFS_I(inode)->root;
3922         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
3923         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
3924
3925         /*
3926          * one for deleting orphan item, one for updating inode and
3927          * two for calling btrfs_truncate_inode_items.
3928          *
3929          * btrfs_truncate_inode_items is a delete operation, it frees
3930          * more space than it uses in most cases. So two units of
3931          * metadata space should be enough for calling it many times.
3932          * If all of the metadata space is used, we can commit
3933          * transaction and use space it freed.
3934          */
3935         u64 num_bytes = calc_trans_metadata_size(root, 4);
3936         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
3937 }
3938
3939 void btrfs_orphan_release_metadata(struct inode *inode)
3940 {
3941         struct btrfs_root *root = BTRFS_I(inode)->root;
3942         u64 num_bytes = calc_trans_metadata_size(root, 4);
3943         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
3944 }
3945
3946 int btrfs_snap_reserve_metadata(struct btrfs_trans_handle *trans,
3947                                 struct btrfs_pending_snapshot *pending)
3948 {
3949         struct btrfs_root *root = pending->root;
3950         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
3951         struct btrfs_block_rsv *dst_rsv = &pending->block_rsv;
3952         /*
3953          * two for root back/forward refs, two for directory entries
3954          * and one for root of the snapshot.
3955          */
3956         u64 num_bytes = calc_trans_metadata_size(root, 5);
3957         dst_rsv->space_info = src_rsv->space_info;
3958         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
3959 }
3960
3961 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes)
3962 {
3963         return num_bytes >>= 3;
3964 }
3965
3966 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
3967 {
3968         struct btrfs_root *root = BTRFS_I(inode)->root;
3969         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
3970         u64 to_reserve;
3971         int nr_extents;
3972         int ret;
3973
3974         if (btrfs_transaction_in_commit(root->fs_info))
3975                 schedule_timeout(1);
3976
3977         num_bytes = ALIGN(num_bytes, root->sectorsize);
3978
3979         spin_lock(&BTRFS_I(inode)->accounting_lock);
3980         nr_extents = atomic_read(&BTRFS_I(inode)->outstanding_extents) + 1;
3981         if (nr_extents > BTRFS_I(inode)->reserved_extents) {
3982                 nr_extents -= BTRFS_I(inode)->reserved_extents;
3983                 to_reserve = calc_trans_metadata_size(root, nr_extents);
3984         } else {
3985                 nr_extents = 0;
3986                 to_reserve = 0;
3987         }
3988         spin_unlock(&BTRFS_I(inode)->accounting_lock);
3989
3990         to_reserve += calc_csum_metadata_size(inode, num_bytes);
3991         ret = reserve_metadata_bytes(NULL, root, block_rsv, to_reserve, 1);
3992         if (ret)
3993                 return ret;
3994
3995         spin_lock(&BTRFS_I(inode)->accounting_lock);
3996         BTRFS_I(inode)->reserved_extents += nr_extents;
3997         atomic_inc(&BTRFS_I(inode)->outstanding_extents);
3998         spin_unlock(&BTRFS_I(inode)->accounting_lock);
3999
4000         block_rsv_add_bytes(block_rsv, to_reserve, 1);
4001
4002         if (block_rsv->size > 512 * 1024 * 1024)
4003                 shrink_delalloc(NULL, root, to_reserve, 0);
4004
4005         return 0;
4006 }
4007
4008 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
4009 {
4010         struct btrfs_root *root = BTRFS_I(inode)->root;
4011         u64 to_free;
4012         int nr_extents;
4013
4014         num_bytes = ALIGN(num_bytes, root->sectorsize);
4015         atomic_dec(&BTRFS_I(inode)->outstanding_extents);
4016
4017         spin_lock(&BTRFS_I(inode)->accounting_lock);
4018         nr_extents = atomic_read(&BTRFS_I(inode)->outstanding_extents);
4019         if (nr_extents < BTRFS_I(inode)->reserved_extents) {
4020                 nr_extents = BTRFS_I(inode)->reserved_extents - nr_extents;
4021                 BTRFS_I(inode)->reserved_extents -= nr_extents;
4022         } else {
4023                 nr_extents = 0;
4024         }
4025         spin_unlock(&BTRFS_I(inode)->accounting_lock);
4026
4027         to_free = calc_csum_metadata_size(inode, num_bytes);
4028         if (nr_extents > 0)
4029                 to_free += calc_trans_metadata_size(root, nr_extents);
4030
4031         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
4032                                 to_free);
4033 }
4034
4035 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
4036 {
4037         int ret;
4038
4039         ret = btrfs_check_data_free_space(inode, num_bytes);
4040         if (ret)
4041                 return ret;
4042
4043         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
4044         if (ret) {
4045                 btrfs_free_reserved_data_space(inode, num_bytes);
4046                 return ret;
4047         }
4048
4049         return 0;
4050 }
4051
4052 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
4053 {
4054         btrfs_delalloc_release_metadata(inode, num_bytes);
4055         btrfs_free_reserved_data_space(inode, num_bytes);
4056 }
4057
4058 static int update_block_group(struct btrfs_trans_handle *trans,
4059                               struct btrfs_root *root,
4060                               u64 bytenr, u64 num_bytes, int alloc)
4061 {
4062         struct btrfs_block_group_cache *cache = NULL;
4063         struct btrfs_fs_info *info = root->fs_info;
4064         u64 total = num_bytes;
4065         u64 old_val;
4066         u64 byte_in_group;
4067         int factor;
4068
4069         /* block accounting for super block */
4070         spin_lock(&info->delalloc_lock);
4071         old_val = btrfs_super_bytes_used(&info->super_copy);
4072         if (alloc)
4073                 old_val += num_bytes;
4074         else
4075                 old_val -= num_bytes;
4076         btrfs_set_super_bytes_used(&info->super_copy, old_val);
4077         spin_unlock(&info->delalloc_lock);
4078
4079         while (total) {
4080                 cache = btrfs_lookup_block_group(info, bytenr);
4081                 if (!cache)
4082                         return -1;
4083                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
4084                                     BTRFS_BLOCK_GROUP_RAID1 |
4085                                     BTRFS_BLOCK_GROUP_RAID10))
4086                         factor = 2;
4087                 else
4088                         factor = 1;
4089                 /*
4090                  * If this block group has free space cache written out, we
4091                  * need to make sure to load it if we are removing space.  This
4092                  * is because we need the unpinning stage to actually add the
4093                  * space back to the block group, otherwise we will leak space.
4094                  */
4095                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
4096                         cache_block_group(cache, trans, NULL, 1);
4097
4098                 byte_in_group = bytenr - cache->key.objectid;
4099                 WARN_ON(byte_in_group > cache->key.offset);
4100
4101                 spin_lock(&cache->space_info->lock);
4102                 spin_lock(&cache->lock);
4103
4104                 if (btrfs_super_cache_generation(&info->super_copy) != 0 &&
4105                     cache->disk_cache_state < BTRFS_DC_CLEAR)
4106                         cache->disk_cache_state = BTRFS_DC_CLEAR;
4107
4108                 cache->dirty = 1;
4109                 old_val = btrfs_block_group_used(&cache->item);
4110                 num_bytes = min(total, cache->key.offset - byte_in_group);
4111                 if (alloc) {
4112                         old_val += num_bytes;
4113                         btrfs_set_block_group_used(&cache->item, old_val);
4114                         cache->reserved -= num_bytes;
4115                         cache->space_info->bytes_reserved -= num_bytes;
4116                         cache->space_info->bytes_used += num_bytes;
4117                         cache->space_info->disk_used += num_bytes * factor;
4118                         spin_unlock(&cache->lock);
4119                         spin_unlock(&cache->space_info->lock);
4120                 } else {
4121                         old_val -= num_bytes;
4122                         btrfs_set_block_group_used(&cache->item, old_val);
4123                         cache->pinned += num_bytes;
4124                         cache->space_info->bytes_pinned += num_bytes;
4125                         cache->space_info->bytes_used -= num_bytes;
4126                         cache->space_info->disk_used -= num_bytes * factor;
4127                         spin_unlock(&cache->lock);
4128                         spin_unlock(&cache->space_info->lock);
4129
4130                         set_extent_dirty(info->pinned_extents,
4131                                          bytenr, bytenr + num_bytes - 1,
4132                                          GFP_NOFS | __GFP_NOFAIL);
4133                 }
4134                 btrfs_put_block_group(cache);
4135                 total -= num_bytes;
4136                 bytenr += num_bytes;
4137         }
4138         return 0;
4139 }
4140
4141 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
4142 {
4143         struct btrfs_block_group_cache *cache;
4144         u64 bytenr;
4145
4146         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
4147         if (!cache)
4148                 return 0;
4149
4150         bytenr = cache->key.objectid;
4151         btrfs_put_block_group(cache);
4152
4153         return bytenr;
4154 }
4155
4156 static int pin_down_extent(struct btrfs_root *root,
4157                            struct btrfs_block_group_cache *cache,
4158                            u64 bytenr, u64 num_bytes, int reserved)
4159 {
4160         spin_lock(&cache->space_info->lock);
4161         spin_lock(&cache->lock);
4162         cache->pinned += num_bytes;
4163         cache->space_info->bytes_pinned += num_bytes;
4164         if (reserved) {
4165                 cache->reserved -= num_bytes;
4166                 cache->space_info->bytes_reserved -= num_bytes;
4167         }
4168         spin_unlock(&cache->lock);
4169         spin_unlock(&cache->space_info->lock);
4170
4171         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
4172                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
4173         return 0;
4174 }
4175
4176 /*
4177  * this function must be called within transaction
4178  */
4179 int btrfs_pin_extent(struct btrfs_root *root,
4180                      u64 bytenr, u64 num_bytes, int reserved)
4181 {
4182         struct btrfs_block_group_cache *cache;
4183
4184         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
4185         BUG_ON(!cache);
4186
4187         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
4188
4189         btrfs_put_block_group(cache);
4190         return 0;
4191 }
4192
4193 /*
4194  * update size of reserved extents. this function may return -EAGAIN
4195  * if 'reserve' is true or 'sinfo' is false.
4196  */
4197 static int update_reserved_bytes(struct btrfs_block_group_cache *cache,
4198                                  u64 num_bytes, int reserve, int sinfo)
4199 {
4200         int ret = 0;
4201         if (sinfo) {
4202                 struct btrfs_space_info *space_info = cache->space_info;
4203                 spin_lock(&space_info->lock);
4204                 spin_lock(&cache->lock);
4205                 if (reserve) {
4206                         if (cache->ro) {
4207                                 ret = -EAGAIN;
4208                         } else {
4209                                 cache->reserved += num_bytes;
4210                                 space_info->bytes_reserved += num_bytes;
4211                         }
4212                 } else {
4213                         if (cache->ro)
4214                                 space_info->bytes_readonly += num_bytes;
4215                         cache->reserved -= num_bytes;
4216                         space_info->bytes_reserved -= num_bytes;
4217                 }
4218                 spin_unlock(&cache->lock);
4219                 spin_unlock(&space_info->lock);
4220         } else {
4221                 spin_lock(&cache->lock);
4222                 if (cache->ro) {
4223                         ret = -EAGAIN;
4224                 } else {
4225                         if (reserve)
4226                                 cache->reserved += num_bytes;
4227                         else
4228                                 cache->reserved -= num_bytes;
4229                 }
4230                 spin_unlock(&cache->lock);
4231         }
4232         return ret;
4233 }
4234
4235 int btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
4236                                 struct btrfs_root *root)
4237 {
4238         struct btrfs_fs_info *fs_info = root->fs_info;
4239         struct btrfs_caching_control *next;
4240         struct btrfs_caching_control *caching_ctl;
4241         struct btrfs_block_group_cache *cache;
4242
4243         down_write(&fs_info->extent_commit_sem);
4244
4245         list_for_each_entry_safe(caching_ctl, next,
4246                                  &fs_info->caching_block_groups, list) {
4247                 cache = caching_ctl->block_group;
4248                 if (block_group_cache_done(cache)) {
4249                         cache->last_byte_to_unpin = (u64)-1;
4250                         list_del_init(&caching_ctl->list);
4251                         put_caching_control(caching_ctl);
4252                 } else {
4253                         cache->last_byte_to_unpin = caching_ctl->progress;
4254                 }
4255         }
4256
4257         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
4258                 fs_info->pinned_extents = &fs_info->freed_extents[1];
4259         else
4260                 fs_info->pinned_extents = &fs_info->freed_extents[0];
4261
4262         up_write(&fs_info->extent_commit_sem);
4263
4264         update_global_block_rsv(fs_info);
4265         return 0;
4266 }
4267
4268 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
4269 {
4270         struct btrfs_fs_info *fs_info = root->fs_info;
4271         struct btrfs_block_group_cache *cache = NULL;
4272         u64 len;
4273
4274         while (start <= end) {
4275                 if (!cache ||
4276                     start >= cache->key.objectid + cache->key.offset) {
4277                         if (cache)
4278                                 btrfs_put_block_group(cache);
4279                         cache = btrfs_lookup_block_group(fs_info, start);
4280                         BUG_ON(!cache);
4281                 }
4282
4283                 len = cache->key.objectid + cache->key.offset - start;
4284                 len = min(len, end + 1 - start);
4285
4286                 if (start < cache->last_byte_to_unpin) {
4287                         len = min(len, cache->last_byte_to_unpin - start);
4288                         btrfs_add_free_space(cache, start, len);
4289                 }
4290
4291                 start += len;
4292
4293                 spin_lock(&cache->space_info->lock);
4294                 spin_lock(&cache->lock);
4295                 cache->pinned -= len;
4296                 cache->space_info->bytes_pinned -= len;
4297                 if (cache->ro) {
4298                         cache->space_info->bytes_readonly += len;
4299                 } else if (cache->reserved_pinned > 0) {
4300                         len = min(len, cache->reserved_pinned);
4301                         cache->reserved_pinned -= len;
4302                         cache->space_info->bytes_reserved += len;
4303                 }
4304                 spin_unlock(&cache->lock);
4305                 spin_unlock(&cache->space_info->lock);
4306         }
4307
4308         if (cache)
4309                 btrfs_put_block_group(cache);
4310         return 0;
4311 }
4312
4313 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
4314                                struct btrfs_root *root)
4315 {
4316         struct btrfs_fs_info *fs_info = root->fs_info;
4317         struct extent_io_tree *unpin;
4318         struct btrfs_block_rsv *block_rsv;
4319         struct btrfs_block_rsv *next_rsv;
4320         u64 start;
4321         u64 end;
4322         int idx;
4323         int ret;
4324
4325         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
4326                 unpin = &fs_info->freed_extents[1];
4327         else
4328                 unpin = &fs_info->freed_extents[0];
4329
4330         while (1) {
4331                 ret = find_first_extent_bit(unpin, 0, &start, &end,
4332                                             EXTENT_DIRTY);
4333                 if (ret)
4334                         break;
4335
4336                 ret = btrfs_discard_extent(root, start, end + 1 - start);
4337
4338                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
4339                 unpin_extent_range(root, start, end);
4340                 cond_resched();
4341         }
4342
4343         mutex_lock(&fs_info->durable_block_rsv_mutex);
4344         list_for_each_entry_safe(block_rsv, next_rsv,
4345                                  &fs_info->durable_block_rsv_list, list) {
4346
4347                 idx = trans->transid & 0x1;
4348                 if (block_rsv->freed[idx] > 0) {
4349                         block_rsv_add_bytes(block_rsv,
4350                                             block_rsv->freed[idx], 0);
4351                         block_rsv->freed[idx] = 0;
4352                 }
4353                 if (atomic_read(&block_rsv->usage) == 0) {
4354                         btrfs_block_rsv_release(root, block_rsv, (u64)-1);
4355
4356                         if (block_rsv->freed[0] == 0 &&
4357                             block_rsv->freed[1] == 0) {
4358                                 list_del_init(&block_rsv->list);
4359                                 kfree(block_rsv);
4360                         }
4361                 } else {
4362                         btrfs_block_rsv_release(root, block_rsv, 0);
4363                 }
4364         }
4365         mutex_unlock(&fs_info->durable_block_rsv_mutex);
4366
4367         return 0;
4368 }
4369
4370 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
4371                                 struct btrfs_root *root,
4372                                 u64 bytenr, u64 num_bytes, u64 parent,
4373                                 u64 root_objectid, u64 owner_objectid,
4374                                 u64 owner_offset, int refs_to_drop,
4375                                 struct btrfs_delayed_extent_op *extent_op)
4376 {
4377         struct btrfs_key key;
4378         struct btrfs_path *path;
4379         struct btrfs_fs_info *info = root->fs_info;
4380         struct btrfs_root *extent_root = info->extent_root;
4381         struct extent_buffer *leaf;
4382         struct btrfs_extent_item *ei;
4383         struct btrfs_extent_inline_ref *iref;
4384         int ret;
4385         int is_data;
4386         int extent_slot = 0;
4387         int found_extent = 0;
4388         int num_to_del = 1;
4389         u32 item_size;
4390         u64 refs;
4391
4392         path = btrfs_alloc_path();
4393         if (!path)
4394                 return -ENOMEM;
4395
4396         path->reada = 1;
4397         path->leave_spinning = 1;
4398
4399         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
4400         BUG_ON(!is_data && refs_to_drop != 1);
4401
4402         ret = lookup_extent_backref(trans, extent_root, path, &iref,
4403                                     bytenr, num_bytes, parent,
4404                                     root_objectid, owner_objectid,
4405                                     owner_offset);
4406         if (ret == 0) {
4407                 extent_slot = path->slots[0];
4408                 while (extent_slot >= 0) {
4409                         btrfs_item_key_to_cpu(path->nodes[0], &key,
4410                                               extent_slot);
4411                         if (key.objectid != bytenr)
4412                                 break;
4413                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
4414                             key.offset == num_bytes) {
4415                                 found_extent = 1;
4416                                 break;
4417                         }
4418                         if (path->slots[0] - extent_slot > 5)
4419                                 break;
4420                         extent_slot--;
4421                 }
4422 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4423                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
4424                 if (found_extent && item_size < sizeof(*ei))
4425                         found_extent = 0;
4426 #endif
4427                 if (!found_extent) {
4428                         BUG_ON(iref);
4429                         ret = remove_extent_backref(trans, extent_root, path,
4430                                                     NULL, refs_to_drop,
4431                                                     is_data);
4432                         BUG_ON(ret);
4433                         btrfs_release_path(extent_root, path);
4434                         path->leave_spinning = 1;
4435
4436                         key.objectid = bytenr;
4437                         key.type = BTRFS_EXTENT_ITEM_KEY;
4438                         key.offset = num_bytes;
4439
4440                         ret = btrfs_search_slot(trans, extent_root,
4441                                                 &key, path, -1, 1);
4442                         if (ret) {
4443                                 printk(KERN_ERR "umm, got %d back from search"
4444                                        ", was looking for %llu\n", ret,
4445                                        (unsigned long long)bytenr);
4446                                 btrfs_print_leaf(extent_root, path->nodes[0]);
4447                         }
4448                         BUG_ON(ret);
4449                         extent_slot = path->slots[0];
4450                 }
4451         } else {
4452                 btrfs_print_leaf(extent_root, path->nodes[0]);
4453                 WARN_ON(1);
4454                 printk(KERN_ERR "btrfs unable to find ref byte nr %llu "
4455                        "parent %llu root %llu  owner %llu offset %llu\n",
4456                        (unsigned long long)bytenr,
4457                        (unsigned long long)parent,
4458                        (unsigned long long)root_objectid,
4459                        (unsigned long long)owner_objectid,
4460                        (unsigned long long)owner_offset);
4461         }
4462
4463         leaf = path->nodes[0];
4464         item_size = btrfs_item_size_nr(leaf, extent_slot);
4465 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4466         if (item_size < sizeof(*ei)) {
4467                 BUG_ON(found_extent || extent_slot != path->slots[0]);
4468                 ret = convert_extent_item_v0(trans, extent_root, path,
4469                                              owner_objectid, 0);
4470                 BUG_ON(ret < 0);
4471
4472                 btrfs_release_path(extent_root, path);
4473                 path->leave_spinning = 1;
4474
4475                 key.objectid = bytenr;
4476                 key.type = BTRFS_EXTENT_ITEM_KEY;
4477                 key.offset = num_bytes;
4478
4479                 ret = btrfs_search_slot(trans, extent_root, &key, path,
4480                                         -1, 1);
4481                 if (ret) {
4482                         printk(KERN_ERR "umm, got %d back from search"
4483                                ", was looking for %llu\n", ret,
4484                                (unsigned long long)bytenr);
4485                         btrfs_print_leaf(extent_root, path->nodes[0]);
4486                 }
4487                 BUG_ON(ret);
4488                 extent_slot = path->slots[0];
4489                 leaf = path->nodes[0];
4490                 item_size = btrfs_item_size_nr(leaf, extent_slot);
4491         }
4492 #endif
4493         BUG_ON(item_size < sizeof(*ei));
4494         ei = btrfs_item_ptr(leaf, extent_slot,
4495                             struct btrfs_extent_item);
4496         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
4497                 struct btrfs_tree_block_info *bi;
4498                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
4499                 bi = (struct btrfs_tree_block_info *)(ei + 1);
4500                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
4501         }
4502
4503         refs = btrfs_extent_refs(leaf, ei);
4504         BUG_ON(refs < refs_to_drop);
4505         refs -= refs_to_drop;
4506
4507         if (refs > 0) {
4508                 if (extent_op)
4509                         __run_delayed_extent_op(extent_op, leaf, ei);
4510                 /*
4511                  * In the case of inline back ref, reference count will
4512                  * be updated by remove_extent_backref
4513                  */
4514                 if (iref) {
4515                         BUG_ON(!found_extent);
4516                 } else {
4517                         btrfs_set_extent_refs(leaf, ei, refs);
4518                         btrfs_mark_buffer_dirty(leaf);
4519                 }
4520                 if (found_extent) {
4521                         ret = remove_extent_backref(trans, extent_root, path,
4522                                                     iref, refs_to_drop,
4523                                                     is_data);
4524                         BUG_ON(ret);
4525                 }
4526         } else {
4527                 if (found_extent) {
4528                         BUG_ON(is_data && refs_to_drop !=
4529                                extent_data_ref_count(root, path, iref));
4530                         if (iref) {
4531                                 BUG_ON(path->slots[0] != extent_slot);
4532                         } else {
4533                                 BUG_ON(path->slots[0] != extent_slot + 1);
4534                                 path->slots[0] = extent_slot;
4535                                 num_to_del = 2;
4536                         }
4537                 }
4538
4539                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
4540                                       num_to_del);
4541                 BUG_ON(ret);
4542                 btrfs_release_path(extent_root, path);
4543
4544                 if (is_data) {
4545                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
4546                         BUG_ON(ret);
4547                 } else {
4548                         invalidate_mapping_pages(info->btree_inode->i_mapping,
4549                              bytenr >> PAGE_CACHE_SHIFT,
4550                              (bytenr + num_bytes - 1) >> PAGE_CACHE_SHIFT);
4551                 }
4552
4553                 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
4554                 BUG_ON(ret);
4555         }
4556         btrfs_free_path(path);
4557         return ret;
4558 }
4559
4560 /*
4561  * when we free an block, it is possible (and likely) that we free the last
4562  * delayed ref for that extent as well.  This searches the delayed ref tree for
4563  * a given extent, and if there are no other delayed refs to be processed, it
4564  * removes it from the tree.
4565  */
4566 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
4567                                       struct btrfs_root *root, u64 bytenr)
4568 {
4569         struct btrfs_delayed_ref_head *head;
4570         struct btrfs_delayed_ref_root *delayed_refs;
4571         struct btrfs_delayed_ref_node *ref;
4572         struct rb_node *node;
4573         int ret = 0;
4574
4575         delayed_refs = &trans->transaction->delayed_refs;
4576         spin_lock(&delayed_refs->lock);
4577         head = btrfs_find_delayed_ref_head(trans, bytenr);
4578         if (!head)
4579                 goto out;
4580
4581         node = rb_prev(&head->node.rb_node);
4582         if (!node)
4583                 goto out;
4584
4585         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
4586
4587         /* there are still entries for this ref, we can't drop it */
4588         if (ref->bytenr == bytenr)
4589                 goto out;
4590
4591         if (head->extent_op) {
4592                 if (!head->must_insert_reserved)
4593                         goto out;
4594                 kfree(head->extent_op);
4595                 head->extent_op = NULL;
4596         }
4597
4598         /*
4599          * waiting for the lock here would deadlock.  If someone else has it
4600          * locked they are already in the process of dropping it anyway
4601          */
4602         if (!mutex_trylock(&head->mutex))
4603                 goto out;
4604
4605         /*
4606          * at this point we have a head with no other entries.  Go
4607          * ahead and process it.
4608          */
4609         head->node.in_tree = 0;
4610         rb_erase(&head->node.rb_node, &delayed_refs->root);
4611
4612         delayed_refs->num_entries--;
4613
4614         /*
4615          * we don't take a ref on the node because we're removing it from the
4616          * tree, so we just steal the ref the tree was holding.
4617          */
4618         delayed_refs->num_heads--;
4619         if (list_empty(&head->cluster))
4620                 delayed_refs->num_heads_ready--;
4621
4622         list_del_init(&head->cluster);
4623         spin_unlock(&delayed_refs->lock);
4624
4625         BUG_ON(head->extent_op);
4626         if (head->must_insert_reserved)
4627                 ret = 1;
4628
4629         mutex_unlock(&head->mutex);
4630         btrfs_put_delayed_ref(&head->node);
4631         return ret;
4632 out:
4633         spin_unlock(&delayed_refs->lock);
4634         return 0;
4635 }
4636
4637 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
4638                            struct btrfs_root *root,
4639                            struct extent_buffer *buf,
4640                            u64 parent, int last_ref)
4641 {
4642         struct btrfs_block_rsv *block_rsv;
4643         struct btrfs_block_group_cache *cache = NULL;
4644         int ret;
4645
4646         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
4647                 ret = btrfs_add_delayed_tree_ref(trans, buf->start, buf->len,
4648                                                 parent, root->root_key.objectid,
4649                                                 btrfs_header_level(buf),
4650                                                 BTRFS_DROP_DELAYED_REF, NULL);
4651                 BUG_ON(ret);
4652         }
4653
4654         if (!last_ref)
4655                 return;
4656
4657         block_rsv = get_block_rsv(trans, root);
4658         cache = btrfs_lookup_block_group(root->fs_info, buf->start);
4659         if (block_rsv->space_info != cache->space_info)
4660                 goto out;
4661
4662         if (btrfs_header_generation(buf) == trans->transid) {
4663                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
4664                         ret = check_ref_cleanup(trans, root, buf->start);
4665                         if (!ret)
4666                                 goto pin;
4667                 }
4668
4669                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
4670                         pin_down_extent(root, cache, buf->start, buf->len, 1);
4671                         goto pin;
4672                 }
4673
4674                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
4675
4676                 btrfs_add_free_space(cache, buf->start, buf->len);
4677                 ret = update_reserved_bytes(cache, buf->len, 0, 0);
4678                 if (ret == -EAGAIN) {
4679                         /* block group became read-only */
4680                         update_reserved_bytes(cache, buf->len, 0, 1);
4681                         goto out;
4682                 }
4683
4684                 ret = 1;
4685                 spin_lock(&block_rsv->lock);
4686                 if (block_rsv->reserved < block_rsv->size) {
4687                         block_rsv->reserved += buf->len;
4688                         ret = 0;
4689                 }
4690                 spin_unlock(&block_rsv->lock);
4691
4692                 if (ret) {
4693                         spin_lock(&cache->space_info->lock);
4694                         cache->space_info->bytes_reserved -= buf->len;
4695                         spin_unlock(&cache->space_info->lock);
4696                 }
4697                 goto out;
4698         }
4699 pin:
4700         if (block_rsv->durable && !cache->ro) {
4701                 ret = 0;
4702                 spin_lock(&cache->lock);
4703                 if (!cache->ro) {
4704                         cache->reserved_pinned += buf->len;
4705                         ret = 1;
4706                 }
4707                 spin_unlock(&cache->lock);
4708
4709                 if (ret) {
4710                         spin_lock(&block_rsv->lock);
4711                         block_rsv->freed[trans->transid & 0x1] += buf->len;
4712                         spin_unlock(&block_rsv->lock);
4713                 }
4714         }
4715 out:
4716         btrfs_put_block_group(cache);
4717 }
4718
4719 int btrfs_free_extent(struct btrfs_trans_handle *trans,
4720                       struct btrfs_root *root,
4721                       u64 bytenr, u64 num_bytes, u64 parent,
4722                       u64 root_objectid, u64 owner, u64 offset)
4723 {
4724         int ret;
4725
4726         /*
4727          * tree log blocks never actually go into the extent allocation
4728          * tree, just update pinning info and exit early.
4729          */
4730         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
4731                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
4732                 /* unlocks the pinned mutex */
4733                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
4734                 ret = 0;
4735         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
4736                 ret = btrfs_add_delayed_tree_ref(trans, bytenr, num_bytes,
4737                                         parent, root_objectid, (int)owner,
4738                                         BTRFS_DROP_DELAYED_REF, NULL);
4739                 BUG_ON(ret);
4740         } else {
4741                 ret = btrfs_add_delayed_data_ref(trans, bytenr, num_bytes,
4742                                         parent, root_objectid, owner,
4743                                         offset, BTRFS_DROP_DELAYED_REF, NULL);
4744                 BUG_ON(ret);
4745         }
4746         return ret;
4747 }
4748
4749 static u64 stripe_align(struct btrfs_root *root, u64 val)
4750 {
4751         u64 mask = ((u64)root->stripesize - 1);
4752         u64 ret = (val + mask) & ~mask;
4753         return ret;
4754 }
4755
4756 /*
4757  * when we wait for progress in the block group caching, its because
4758  * our allocation attempt failed at least once.  So, we must sleep
4759  * and let some progress happen before we try again.
4760  *
4761  * This function will sleep at least once waiting for new free space to
4762  * show up, and then it will check the block group free space numbers
4763  * for our min num_bytes.  Another option is to have it go ahead
4764  * and look in the rbtree for a free extent of a given size, but this
4765  * is a good start.
4766  */
4767 static noinline int
4768 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
4769                                 u64 num_bytes)
4770 {
4771         struct btrfs_caching_control *caching_ctl;
4772         DEFINE_WAIT(wait);
4773
4774         caching_ctl = get_caching_control(cache);
4775         if (!caching_ctl)
4776                 return 0;
4777
4778         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
4779                    (cache->free_space >= num_bytes));
4780
4781         put_caching_control(caching_ctl);
4782         return 0;
4783 }
4784
4785 static noinline int
4786 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
4787 {
4788         struct btrfs_caching_control *caching_ctl;
4789         DEFINE_WAIT(wait);
4790
4791         caching_ctl = get_caching_control(cache);
4792         if (!caching_ctl)
4793                 return 0;
4794
4795         wait_event(caching_ctl->wait, block_group_cache_done(cache));
4796
4797         put_caching_control(caching_ctl);
4798         return 0;
4799 }
4800
4801 static int get_block_group_index(struct btrfs_block_group_cache *cache)
4802 {
4803         int index;
4804         if (cache->flags & BTRFS_BLOCK_GROUP_RAID10)
4805                 index = 0;
4806         else if (cache->flags & BTRFS_BLOCK_GROUP_RAID1)
4807                 index = 1;
4808         else if (cache->flags & BTRFS_BLOCK_GROUP_DUP)
4809                 index = 2;
4810         else if (cache->flags & BTRFS_BLOCK_GROUP_RAID0)
4811                 index = 3;
4812         else
4813                 index = 4;
4814         return index;
4815 }
4816
4817 enum btrfs_loop_type {
4818         LOOP_FIND_IDEAL = 0,
4819         LOOP_CACHING_NOWAIT = 1,
4820         LOOP_CACHING_WAIT = 2,
4821         LOOP_ALLOC_CHUNK = 3,
4822         LOOP_NO_EMPTY_SIZE = 4,
4823 };
4824
4825 /*
4826  * walks the btree of allocated extents and find a hole of a given size.
4827  * The key ins is changed to record the hole:
4828  * ins->objectid == block start
4829  * ins->flags = BTRFS_EXTENT_ITEM_KEY
4830  * ins->offset == number of blocks
4831  * Any available blocks before search_start are skipped.
4832  */
4833 static noinline int find_free_extent(struct btrfs_trans_handle *trans,
4834                                      struct btrfs_root *orig_root,
4835                                      u64 num_bytes, u64 empty_size,
4836                                      u64 search_start, u64 search_end,
4837                                      u64 hint_byte, struct btrfs_key *ins,
4838                                      int data)
4839 {
4840         int ret = 0;
4841         struct btrfs_root *root = orig_root->fs_info->extent_root;
4842         struct btrfs_free_cluster *last_ptr = NULL;
4843         struct btrfs_block_group_cache *block_group = NULL;
4844         int empty_cluster = 2 * 1024 * 1024;
4845         int allowed_chunk_alloc = 0;
4846         int done_chunk_alloc = 0;
4847         struct btrfs_space_info *space_info;
4848         int last_ptr_loop = 0;
4849         int loop = 0;
4850         int index = 0;
4851         bool found_uncached_bg = false;
4852         bool failed_cluster_refill = false;
4853         bool failed_alloc = false;
4854         bool use_cluster = true;
4855         u64 ideal_cache_percent = 0;
4856         u64 ideal_cache_offset = 0;
4857
4858         WARN_ON(num_bytes < root->sectorsize);
4859         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
4860         ins->objectid = 0;
4861         ins->offset = 0;
4862
4863         space_info = __find_space_info(root->fs_info, data);
4864         if (!space_info) {
4865                 printk(KERN_ERR "No space info for %d\n", data);
4866                 return -ENOSPC;
4867         }
4868
4869         /*
4870          * If the space info is for both data and metadata it means we have a
4871          * small filesystem and we can't use the clustering stuff.
4872          */
4873         if (btrfs_mixed_space_info(space_info))
4874                 use_cluster = false;
4875
4876         if (orig_root->ref_cows || empty_size)
4877                 allowed_chunk_alloc = 1;
4878
4879         if (data & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
4880                 last_ptr = &root->fs_info->meta_alloc_cluster;
4881                 if (!btrfs_test_opt(root, SSD))
4882                         empty_cluster = 64 * 1024;
4883         }
4884
4885         if ((data & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
4886             btrfs_test_opt(root, SSD)) {
4887                 last_ptr = &root->fs_info->data_alloc_cluster;
4888         }
4889
4890         if (last_ptr) {
4891                 spin_lock(&last_ptr->lock);
4892                 if (last_ptr->block_group)
4893                         hint_byte = last_ptr->window_start;
4894                 spin_unlock(&last_ptr->lock);
4895         }
4896
4897         search_start = max(search_start, first_logical_byte(root, 0));
4898         search_start = max(search_start, hint_byte);
4899
4900         if (!last_ptr)
4901                 empty_cluster = 0;
4902
4903         if (search_start == hint_byte) {
4904 ideal_cache:
4905                 block_group = btrfs_lookup_block_group(root->fs_info,
4906                                                        search_start);
4907                 /*
4908                  * we don't want to use the block group if it doesn't match our
4909                  * allocation bits, or if its not cached.
4910                  *
4911                  * However if we are re-searching with an ideal block group
4912                  * picked out then we don't care that the block group is cached.
4913                  */
4914                 if (block_group && block_group_bits(block_group, data) &&
4915                     (block_group->cached != BTRFS_CACHE_NO ||
4916                      search_start == ideal_cache_offset)) {
4917                         down_read(&space_info->groups_sem);
4918                         if (list_empty(&block_group->list) ||
4919                             block_group->ro) {
4920                                 /*
4921                                  * someone is removing this block group,
4922                                  * we can't jump into the have_block_group
4923                                  * target because our list pointers are not
4924                                  * valid
4925                                  */
4926                                 btrfs_put_block_group(block_group);
4927                                 up_read(&space_info->groups_sem);
4928                         } else {
4929                                 index = get_block_group_index(block_group);
4930                                 goto have_block_group;
4931                         }
4932                 } else if (block_group) {
4933                         btrfs_put_block_group(block_group);
4934                 }
4935         }
4936 search:
4937         down_read(&space_info->groups_sem);
4938         list_for_each_entry(block_group, &space_info->block_groups[index],
4939                             list) {
4940                 u64 offset;
4941                 int cached;
4942
4943                 btrfs_get_block_group(block_group);
4944                 search_start = block_group->key.objectid;
4945
4946                 /*
4947                  * this can happen if we end up cycling through all the
4948                  * raid types, but we want to make sure we only allocate
4949                  * for the proper type.
4950                  */
4951                 if (!block_group_bits(block_group, data)) {
4952                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
4953                                 BTRFS_BLOCK_GROUP_RAID1 |
4954                                 BTRFS_BLOCK_GROUP_RAID10;
4955
4956                         /*
4957                          * if they asked for extra copies and this block group
4958                          * doesn't provide them, bail.  This does allow us to
4959                          * fill raid0 from raid1.
4960                          */
4961                         if ((data & extra) && !(block_group->flags & extra))
4962                                 goto loop;
4963                 }
4964
4965 have_block_group:
4966                 if (unlikely(block_group->cached == BTRFS_CACHE_NO)) {
4967                         u64 free_percent;
4968
4969                         ret = cache_block_group(block_group, trans,
4970                                                 orig_root, 1);
4971                         if (block_group->cached == BTRFS_CACHE_FINISHED)
4972                                 goto have_block_group;
4973
4974                         free_percent = btrfs_block_group_used(&block_group->item);
4975                         free_percent *= 100;
4976                         free_percent = div64_u64(free_percent,
4977                                                  block_group->key.offset);
4978                         free_percent = 100 - free_percent;
4979                         if (free_percent > ideal_cache_percent &&
4980                             likely(!block_group->ro)) {
4981                                 ideal_cache_offset = block_group->key.objectid;
4982                                 ideal_cache_percent = free_percent;
4983                         }
4984
4985                         /*
4986                          * We only want to start kthread caching if we are at
4987                          * the point where we will wait for caching to make
4988                          * progress, or if our ideal search is over and we've
4989                          * found somebody to start caching.
4990                          */
4991                         if (loop > LOOP_CACHING_NOWAIT ||
4992                             (loop > LOOP_FIND_IDEAL &&
4993                              atomic_read(&space_info->caching_threads) < 2)) {
4994                                 ret = cache_block_group(block_group, trans,
4995                                                         orig_root, 0);
4996                                 BUG_ON(ret);
4997                         }
4998                         found_uncached_bg = true;
4999
5000                         /*
5001                          * If loop is set for cached only, try the next block
5002                          * group.
5003                          */
5004                         if (loop == LOOP_FIND_IDEAL)
5005                                 goto loop;
5006                 }
5007
5008                 cached = block_group_cache_done(block_group);
5009                 if (unlikely(!cached))
5010                         found_uncached_bg = true;
5011
5012                 if (unlikely(block_group->ro))
5013                         goto loop;
5014
5015                 /*
5016                  * Ok we want to try and use the cluster allocator, so lets look
5017                  * there, unless we are on LOOP_NO_EMPTY_SIZE, since we will
5018                  * have tried the cluster allocator plenty of times at this
5019                  * point and not have found anything, so we are likely way too
5020                  * fragmented for the clustering stuff to find anything, so lets
5021                  * just skip it and let the allocator find whatever block it can
5022                  * find
5023                  */
5024                 if (last_ptr && loop < LOOP_NO_EMPTY_SIZE) {
5025                         /*
5026                          * the refill lock keeps out other
5027                          * people trying to start a new cluster
5028                          */
5029                         spin_lock(&last_ptr->refill_lock);
5030                         if (last_ptr->block_group &&
5031                             (last_ptr->block_group->ro ||
5032                             !block_group_bits(last_ptr->block_group, data))) {
5033                                 offset = 0;
5034                                 goto refill_cluster;
5035                         }
5036
5037                         offset = btrfs_alloc_from_cluster(block_group, last_ptr,
5038                                                  num_bytes, search_start);
5039                         if (offset) {
5040                                 /* we have a block, we're done */
5041                                 spin_unlock(&last_ptr->refill_lock);
5042                                 goto checks;
5043                         }
5044
5045                         spin_lock(&last_ptr->lock);
5046                         /*
5047                          * whoops, this cluster doesn't actually point to
5048                          * this block group.  Get a ref on the block
5049                          * group is does point to and try again
5050                          */
5051                         if (!last_ptr_loop && last_ptr->block_group &&
5052                             last_ptr->block_group != block_group) {
5053
5054                                 btrfs_put_block_group(block_group);
5055                                 block_group = last_ptr->block_group;
5056                                 btrfs_get_block_group(block_group);
5057                                 spin_unlock(&last_ptr->lock);
5058                                 spin_unlock(&last_ptr->refill_lock);
5059
5060                                 last_ptr_loop = 1;
5061                                 search_start = block_group->key.objectid;
5062                                 /*
5063                                  * we know this block group is properly
5064                                  * in the list because
5065                                  * btrfs_remove_block_group, drops the
5066                                  * cluster before it removes the block
5067                                  * group from the list
5068                                  */
5069                                 goto have_block_group;
5070                         }
5071                         spin_unlock(&last_ptr->lock);
5072 refill_cluster:
5073                         /*
5074                          * this cluster didn't work out, free it and
5075                          * start over
5076                          */
5077                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5078
5079                         last_ptr_loop = 0;
5080
5081                         /* allocate a cluster in this block group */
5082                         ret = btrfs_find_space_cluster(trans, root,
5083                                                block_group, last_ptr,
5084                                                offset, num_bytes,
5085                                                empty_cluster + empty_size);
5086                         if (ret == 0) {
5087                                 /*
5088                                  * now pull our allocation out of this
5089                                  * cluster
5090                                  */
5091                                 offset = btrfs_alloc_from_cluster(block_group,
5092                                                   last_ptr, num_bytes,
5093                                                   search_start);
5094                                 if (offset) {
5095                                         /* we found one, proceed */
5096                                         spin_unlock(&last_ptr->refill_lock);
5097                                         goto checks;
5098                                 }
5099                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
5100                                    && !failed_cluster_refill) {
5101                                 spin_unlock(&last_ptr->refill_lock);
5102
5103                                 failed_cluster_refill = true;
5104                                 wait_block_group_cache_progress(block_group,
5105                                        num_bytes + empty_cluster + empty_size);
5106                                 goto have_block_group;
5107                         }
5108
5109                         /*
5110                          * at this point we either didn't find a cluster
5111                          * or we weren't able to allocate a block from our
5112                          * cluster.  Free the cluster we've been trying
5113                          * to use, and go to the next block group
5114                          */
5115                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5116                         spin_unlock(&last_ptr->refill_lock);
5117                         goto loop;
5118                 }
5119
5120                 offset = btrfs_find_space_for_alloc(block_group, search_start,
5121                                                     num_bytes, empty_size);
5122                 /*
5123                  * If we didn't find a chunk, and we haven't failed on this
5124                  * block group before, and this block group is in the middle of
5125                  * caching and we are ok with waiting, then go ahead and wait
5126                  * for progress to be made, and set failed_alloc to true.
5127                  *
5128                  * If failed_alloc is true then we've already waited on this
5129                  * block group once and should move on to the next block group.
5130                  */
5131                 if (!offset && !failed_alloc && !cached &&
5132                     loop > LOOP_CACHING_NOWAIT) {
5133                         wait_block_group_cache_progress(block_group,
5134                                                 num_bytes + empty_size);
5135                         failed_alloc = true;
5136                         goto have_block_group;
5137                 } else if (!offset) {
5138                         goto loop;
5139                 }
5140 checks:
5141                 search_start = stripe_align(root, offset);
5142                 /* move on to the next group */
5143                 if (search_start + num_bytes >= search_end) {
5144                         btrfs_add_free_space(block_group, offset, num_bytes);
5145                         goto loop;
5146                 }
5147
5148                 /* move on to the next group */
5149                 if (search_start + num_bytes >
5150                     block_group->key.objectid + block_group->key.offset) {
5151                         btrfs_add_free_space(block_group, offset, num_bytes);
5152                         goto loop;
5153                 }
5154
5155                 ins->objectid = search_start;
5156                 ins->offset = num_bytes;
5157
5158                 if (offset < search_start)
5159                         btrfs_add_free_space(block_group, offset,
5160                                              search_start - offset);
5161                 BUG_ON(offset > search_start);
5162
5163                 ret = update_reserved_bytes(block_group, num_bytes, 1,
5164                                             (data & BTRFS_BLOCK_GROUP_DATA));
5165                 if (ret == -EAGAIN) {
5166                         btrfs_add_free_space(block_group, offset, num_bytes);
5167                         goto loop;
5168                 }
5169
5170                 /* we are all good, lets return */
5171                 ins->objectid = search_start;
5172                 ins->offset = num_bytes;
5173
5174                 if (offset < search_start)
5175                         btrfs_add_free_space(block_group, offset,
5176                                              search_start - offset);
5177                 BUG_ON(offset > search_start);
5178                 break;
5179 loop:
5180                 failed_cluster_refill = false;
5181                 failed_alloc = false;
5182                 BUG_ON(index != get_block_group_index(block_group));
5183                 btrfs_put_block_group(block_group);
5184         }
5185         up_read(&space_info->groups_sem);
5186
5187         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
5188                 goto search;
5189
5190         /* LOOP_FIND_IDEAL, only search caching/cached bg's, and don't wait for
5191          *                      for them to make caching progress.  Also
5192          *                      determine the best possible bg to cache
5193          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
5194          *                      caching kthreads as we move along
5195          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
5196          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
5197          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
5198          *                      again
5199          */
5200         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE &&
5201             (found_uncached_bg || empty_size || empty_cluster ||
5202              allowed_chunk_alloc)) {
5203                 index = 0;
5204                 if (loop == LOOP_FIND_IDEAL && found_uncached_bg) {
5205                         found_uncached_bg = false;
5206                         loop++;
5207                         if (!ideal_cache_percent &&
5208                             atomic_read(&space_info->caching_threads))
5209                                 goto search;
5210
5211                         /*
5212                          * 1 of the following 2 things have happened so far
5213                          *
5214                          * 1) We found an ideal block group for caching that
5215                          * is mostly full and will cache quickly, so we might
5216                          * as well wait for it.
5217                          *
5218                          * 2) We searched for cached only and we didn't find
5219                          * anything, and we didn't start any caching kthreads
5220                          * either, so chances are we will loop through and
5221                          * start a couple caching kthreads, and then come back
5222                          * around and just wait for them.  This will be slower
5223                          * because we will have 2 caching kthreads reading at
5224                          * the same time when we could have just started one
5225                          * and waited for it to get far enough to give us an
5226                          * allocation, so go ahead and go to the wait caching
5227                          * loop.
5228                          */
5229                         loop = LOOP_CACHING_WAIT;
5230                         search_start = ideal_cache_offset;
5231                         ideal_cache_percent = 0;
5232                         goto ideal_cache;
5233                 } else if (loop == LOOP_FIND_IDEAL) {
5234                         /*
5235                          * Didn't find a uncached bg, wait on anything we find
5236                          * next.
5237                          */
5238                         loop = LOOP_CACHING_WAIT;
5239                         goto search;
5240                 }
5241
5242                 if (loop < LOOP_CACHING_WAIT) {
5243                         loop++;
5244                         goto search;
5245                 }
5246
5247                 if (loop == LOOP_ALLOC_CHUNK) {
5248                         empty_size = 0;
5249                         empty_cluster = 0;
5250                 }
5251
5252                 if (allowed_chunk_alloc) {
5253                         ret = do_chunk_alloc(trans, root, num_bytes +
5254                                              2 * 1024 * 1024, data, 1);
5255                         allowed_chunk_alloc = 0;
5256                         done_chunk_alloc = 1;
5257                 } else if (!done_chunk_alloc) {
5258                         space_info->force_alloc = 1;
5259                 }
5260
5261                 if (loop < LOOP_NO_EMPTY_SIZE) {
5262                         loop++;
5263                         goto search;
5264                 }
5265                 ret = -ENOSPC;
5266         } else if (!ins->objectid) {
5267                 ret = -ENOSPC;
5268         }
5269
5270         /* we found what we needed */
5271         if (ins->objectid) {
5272                 if (!(data & BTRFS_BLOCK_GROUP_DATA))
5273                         trans->block_group = block_group->key.objectid;
5274
5275                 btrfs_put_block_group(block_group);
5276                 ret = 0;
5277         }
5278
5279         return ret;
5280 }
5281
5282 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
5283                             int dump_block_groups)
5284 {
5285         struct btrfs_block_group_cache *cache;
5286         int index = 0;
5287
5288         spin_lock(&info->lock);
5289         printk(KERN_INFO "space_info has %llu free, is %sfull\n",
5290                (unsigned long long)(info->total_bytes - info->bytes_used -
5291                                     info->bytes_pinned - info->bytes_reserved -
5292                                     info->bytes_readonly),
5293                (info->full) ? "" : "not ");
5294         printk(KERN_INFO "space_info total=%llu, used=%llu, pinned=%llu, "
5295                "reserved=%llu, may_use=%llu, readonly=%llu\n",
5296                (unsigned long long)info->total_bytes,
5297                (unsigned long long)info->bytes_used,
5298                (unsigned long long)info->bytes_pinned,
5299                (unsigned long long)info->bytes_reserved,
5300                (unsigned long long)info->bytes_may_use,
5301                (unsigned long long)info->bytes_readonly);
5302         spin_unlock(&info->lock);
5303
5304         if (!dump_block_groups)
5305                 return;
5306
5307         down_read(&info->groups_sem);
5308 again:
5309         list_for_each_entry(cache, &info->block_groups[index], list) {
5310                 spin_lock(&cache->lock);
5311                 printk(KERN_INFO "block group %llu has %llu bytes, %llu used "
5312                        "%llu pinned %llu reserved\n",
5313                        (unsigned long long)cache->key.objectid,
5314                        (unsigned long long)cache->key.offset,
5315                        (unsigned long long)btrfs_block_group_used(&cache->item),
5316                        (unsigned long long)cache->pinned,
5317                        (unsigned long long)cache->reserved);
5318                 btrfs_dump_free_space(cache, bytes);
5319                 spin_unlock(&cache->lock);
5320         }
5321         if (++index < BTRFS_NR_RAID_TYPES)
5322                 goto again;
5323         up_read(&info->groups_sem);
5324 }
5325
5326 int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
5327                          struct btrfs_root *root,
5328                          u64 num_bytes, u64 min_alloc_size,
5329                          u64 empty_size, u64 hint_byte,
5330                          u64 search_end, struct btrfs_key *ins,
5331                          u64 data)
5332 {
5333         int ret;
5334         u64 search_start = 0;
5335
5336         data = btrfs_get_alloc_profile(root, data);
5337 again:
5338         /*
5339          * the only place that sets empty_size is btrfs_realloc_node, which
5340          * is not called recursively on allocations
5341          */
5342         if (empty_size || root->ref_cows)
5343                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
5344                                      num_bytes + 2 * 1024 * 1024, data, 0);
5345
5346         WARN_ON(num_bytes < root->sectorsize);
5347         ret = find_free_extent(trans, root, num_bytes, empty_size,
5348                                search_start, search_end, hint_byte,
5349                                ins, data);
5350
5351         if (ret == -ENOSPC && num_bytes > min_alloc_size) {
5352                 num_bytes = num_bytes >> 1;
5353                 num_bytes = num_bytes & ~(root->sectorsize - 1);
5354                 num_bytes = max(num_bytes, min_alloc_size);
5355                 do_chunk_alloc(trans, root->fs_info->extent_root,
5356                                num_bytes, data, 1);
5357                 goto again;
5358         }
5359         if (ret == -ENOSPC) {
5360                 struct btrfs_space_info *sinfo;
5361
5362                 sinfo = __find_space_info(root->fs_info, data);
5363                 printk(KERN_ERR "btrfs allocation failed flags %llu, "
5364                        "wanted %llu\n", (unsigned long long)data,
5365                        (unsigned long long)num_bytes);
5366                 dump_space_info(sinfo, num_bytes, 1);
5367         }
5368
5369         return ret;
5370 }
5371
5372 int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len)
5373 {
5374         struct btrfs_block_group_cache *cache;
5375         int ret = 0;
5376
5377         cache = btrfs_lookup_block_group(root->fs_info, start);
5378         if (!cache) {
5379                 printk(KERN_ERR "Unable to find block group for %llu\n",
5380                        (unsigned long long)start);
5381                 return -ENOSPC;
5382         }
5383
5384         ret = btrfs_discard_extent(root, start, len);
5385
5386         btrfs_add_free_space(cache, start, len);
5387         update_reserved_bytes(cache, len, 0, 1);
5388         btrfs_put_block_group(cache);
5389
5390         return ret;
5391 }
5392
5393 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
5394                                       struct btrfs_root *root,
5395                                       u64 parent, u64 root_objectid,
5396                                       u64 flags, u64 owner, u64 offset,
5397                                       struct btrfs_key *ins, int ref_mod)
5398 {
5399         int ret;
5400         struct btrfs_fs_info *fs_info = root->fs_info;
5401         struct btrfs_extent_item *extent_item;
5402         struct btrfs_extent_inline_ref *iref;
5403         struct btrfs_path *path;
5404         struct extent_buffer *leaf;
5405         int type;
5406         u32 size;
5407
5408         if (parent > 0)
5409                 type = BTRFS_SHARED_DATA_REF_KEY;
5410         else
5411                 type = BTRFS_EXTENT_DATA_REF_KEY;
5412
5413         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
5414
5415         path = btrfs_alloc_path();
5416         BUG_ON(!path);
5417
5418         path->leave_spinning = 1;
5419         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
5420                                       ins, size);
5421         BUG_ON(ret);
5422
5423         leaf = path->nodes[0];
5424         extent_item = btrfs_item_ptr(leaf, path->slots[0],
5425                                      struct btrfs_extent_item);
5426         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
5427         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
5428         btrfs_set_extent_flags(leaf, extent_item,
5429                                flags | BTRFS_EXTENT_FLAG_DATA);
5430
5431         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
5432         btrfs_set_extent_inline_ref_type(leaf, iref, type);
5433         if (parent > 0) {
5434                 struct btrfs_shared_data_ref *ref;
5435                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
5436                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
5437                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
5438         } else {
5439                 struct btrfs_extent_data_ref *ref;
5440                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
5441                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
5442                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
5443                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
5444                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
5445         }
5446
5447         btrfs_mark_buffer_dirty(path->nodes[0]);
5448         btrfs_free_path(path);
5449
5450         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
5451         if (ret) {
5452                 printk(KERN_ERR "btrfs update block group failed for %llu "
5453                        "%llu\n", (unsigned long long)ins->objectid,
5454                        (unsigned long long)ins->offset);
5455                 BUG();
5456         }
5457         return ret;
5458 }
5459
5460 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
5461                                      struct btrfs_root *root,
5462                                      u64 parent, u64 root_objectid,
5463                                      u64 flags, struct btrfs_disk_key *key,
5464                                      int level, struct btrfs_key *ins)
5465 {
5466         int ret;
5467         struct btrfs_fs_info *fs_info = root->fs_info;
5468         struct btrfs_extent_item *extent_item;
5469         struct btrfs_tree_block_info *block_info;
5470         struct btrfs_extent_inline_ref *iref;
5471         struct btrfs_path *path;
5472         struct extent_buffer *leaf;
5473         u32 size = sizeof(*extent_item) + sizeof(*block_info) + sizeof(*iref);
5474
5475         path = btrfs_alloc_path();
5476         BUG_ON(!path);
5477
5478         path->leave_spinning = 1;
5479         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
5480                                       ins, size);
5481         BUG_ON(ret);
5482
5483         leaf = path->nodes[0];
5484         extent_item = btrfs_item_ptr(leaf, path->slots[0],
5485                                      struct btrfs_extent_item);
5486         btrfs_set_extent_refs(leaf, extent_item, 1);
5487         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
5488         btrfs_set_extent_flags(leaf, extent_item,
5489                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
5490         block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
5491
5492         btrfs_set_tree_block_key(leaf, block_info, key);
5493         btrfs_set_tree_block_level(leaf, block_info, level);
5494
5495         iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
5496         if (parent > 0) {
5497                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
5498                 btrfs_set_extent_inline_ref_type(leaf, iref,
5499                                                  BTRFS_SHARED_BLOCK_REF_KEY);
5500                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
5501         } else {
5502                 btrfs_set_extent_inline_ref_type(leaf, iref,
5503                                                  BTRFS_TREE_BLOCK_REF_KEY);
5504                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
5505         }
5506
5507         btrfs_mark_buffer_dirty(leaf);
5508         btrfs_free_path(path);
5509
5510         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
5511         if (ret) {
5512                 printk(KERN_ERR "btrfs update block group failed for %llu "
5513                        "%llu\n", (unsigned long long)ins->objectid,
5514                        (unsigned long long)ins->offset);
5515                 BUG();
5516         }
5517         return ret;
5518 }
5519
5520 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
5521                                      struct btrfs_root *root,
5522                                      u64 root_objectid, u64 owner,
5523                                      u64 offset, struct btrfs_key *ins)
5524 {
5525         int ret;
5526
5527         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
5528
5529         ret = btrfs_add_delayed_data_ref(trans, ins->objectid, ins->offset,
5530                                          0, root_objectid, owner, offset,
5531                                          BTRFS_ADD_DELAYED_EXTENT, NULL);
5532         return ret;
5533 }
5534
5535 /*
5536  * this is used by the tree logging recovery code.  It records that
5537  * an extent has been allocated and makes sure to clear the free
5538  * space cache bits as well
5539  */
5540 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
5541                                    struct btrfs_root *root,
5542                                    u64 root_objectid, u64 owner, u64 offset,
5543                                    struct btrfs_key *ins)
5544 {
5545         int ret;
5546         struct btrfs_block_group_cache *block_group;
5547         struct btrfs_caching_control *caching_ctl;
5548         u64 start = ins->objectid;
5549         u64 num_bytes = ins->offset;
5550
5551         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
5552         cache_block_group(block_group, trans, NULL, 0);
5553         caching_ctl = get_caching_control(block_group);
5554
5555         if (!caching_ctl) {
5556                 BUG_ON(!block_group_cache_done(block_group));
5557                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
5558                 BUG_ON(ret);
5559         } else {
5560                 mutex_lock(&caching_ctl->mutex);
5561
5562                 if (start >= caching_ctl->progress) {
5563                         ret = add_excluded_extent(root, start, num_bytes);
5564                         BUG_ON(ret);
5565                 } else if (start + num_bytes <= caching_ctl->progress) {
5566                         ret = btrfs_remove_free_space(block_group,
5567                                                       start, num_bytes);
5568                         BUG_ON(ret);
5569                 } else {
5570                         num_bytes = caching_ctl->progress - start;
5571                         ret = btrfs_remove_free_space(block_group,
5572                                                       start, num_bytes);
5573                         BUG_ON(ret);
5574
5575                         start = caching_ctl->progress;
5576                         num_bytes = ins->objectid + ins->offset -
5577                                     caching_ctl->progress;
5578                         ret = add_excluded_extent(root, start, num_bytes);
5579                         BUG_ON(ret);
5580                 }
5581
5582                 mutex_unlock(&caching_ctl->mutex);
5583                 put_caching_control(caching_ctl);
5584         }
5585
5586         ret = update_reserved_bytes(block_group, ins->offset, 1, 1);
5587         BUG_ON(ret);
5588         btrfs_put_block_group(block_group);
5589         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
5590                                          0, owner, offset, ins, 1);
5591         return ret;
5592 }
5593
5594 struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
5595                                             struct btrfs_root *root,
5596                                             u64 bytenr, u32 blocksize,
5597                                             int level)
5598 {
5599         struct extent_buffer *buf;
5600
5601         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
5602         if (!buf)
5603                 return ERR_PTR(-ENOMEM);
5604         btrfs_set_header_generation(buf, trans->transid);
5605         btrfs_set_buffer_lockdep_class(buf, level);
5606         btrfs_tree_lock(buf);