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[linux.git] / fs / btrfs / block-group.c
1 // SPDX-License-Identifier: GPL-2.0
2
3 #include "misc.h"
4 #include "ctree.h"
5 #include "block-group.h"
6 #include "space-info.h"
7 #include "disk-io.h"
8 #include "free-space-cache.h"
9 #include "free-space-tree.h"
10 #include "disk-io.h"
11 #include "volumes.h"
12 #include "transaction.h"
13 #include "ref-verify.h"
14 #include "sysfs.h"
15 #include "tree-log.h"
16 #include "delalloc-space.h"
17 #include "discard.h"
18 #include "raid56.h"
19
20 /*
21  * Return target flags in extended format or 0 if restripe for this chunk_type
22  * is not in progress
23  *
24  * Should be called with balance_lock held
25  */
26 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
27 {
28         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
29         u64 target = 0;
30
31         if (!bctl)
32                 return 0;
33
34         if (flags & BTRFS_BLOCK_GROUP_DATA &&
35             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
36                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
37         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
38                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
39                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
40         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
41                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
42                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
43         }
44
45         return target;
46 }
47
48 /*
49  * @flags: available profiles in extended format (see ctree.h)
50  *
51  * Return reduced profile in chunk format.  If profile changing is in progress
52  * (either running or paused) picks the target profile (if it's already
53  * available), otherwise falls back to plain reducing.
54  */
55 static u64 btrfs_reduce_alloc_profile(struct btrfs_fs_info *fs_info, u64 flags)
56 {
57         u64 num_devices = fs_info->fs_devices->rw_devices;
58         u64 target;
59         u64 raid_type;
60         u64 allowed = 0;
61
62         /*
63          * See if restripe for this chunk_type is in progress, if so try to
64          * reduce to the target profile
65          */
66         spin_lock(&fs_info->balance_lock);
67         target = get_restripe_target(fs_info, flags);
68         if (target) {
69                 /* Pick target profile only if it's already available */
70                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
71                         spin_unlock(&fs_info->balance_lock);
72                         return extended_to_chunk(target);
73                 }
74         }
75         spin_unlock(&fs_info->balance_lock);
76
77         /* First, mask out the RAID levels which aren't possible */
78         for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
79                 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
80                         allowed |= btrfs_raid_array[raid_type].bg_flag;
81         }
82         allowed &= flags;
83
84         if (allowed & BTRFS_BLOCK_GROUP_RAID6)
85                 allowed = BTRFS_BLOCK_GROUP_RAID6;
86         else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
87                 allowed = BTRFS_BLOCK_GROUP_RAID5;
88         else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
89                 allowed = BTRFS_BLOCK_GROUP_RAID10;
90         else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
91                 allowed = BTRFS_BLOCK_GROUP_RAID1;
92         else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
93                 allowed = BTRFS_BLOCK_GROUP_RAID0;
94
95         flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
96
97         return extended_to_chunk(flags | allowed);
98 }
99
100 u64 btrfs_get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags)
101 {
102         unsigned seq;
103         u64 flags;
104
105         do {
106                 flags = orig_flags;
107                 seq = read_seqbegin(&fs_info->profiles_lock);
108
109                 if (flags & BTRFS_BLOCK_GROUP_DATA)
110                         flags |= fs_info->avail_data_alloc_bits;
111                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
112                         flags |= fs_info->avail_system_alloc_bits;
113                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
114                         flags |= fs_info->avail_metadata_alloc_bits;
115         } while (read_seqretry(&fs_info->profiles_lock, seq));
116
117         return btrfs_reduce_alloc_profile(fs_info, flags);
118 }
119
120 void btrfs_get_block_group(struct btrfs_block_group *cache)
121 {
122         atomic_inc(&cache->count);
123 }
124
125 void btrfs_put_block_group(struct btrfs_block_group *cache)
126 {
127         if (atomic_dec_and_test(&cache->count)) {
128                 WARN_ON(cache->pinned > 0);
129                 WARN_ON(cache->reserved > 0);
130
131                 /*
132                  * A block_group shouldn't be on the discard_list anymore.
133                  * Remove the block_group from the discard_list to prevent us
134                  * from causing a panic due to NULL pointer dereference.
135                  */
136                 if (WARN_ON(!list_empty(&cache->discard_list)))
137                         btrfs_discard_cancel_work(&cache->fs_info->discard_ctl,
138                                                   cache);
139
140                 /*
141                  * If not empty, someone is still holding mutex of
142                  * full_stripe_lock, which can only be released by caller.
143                  * And it will definitely cause use-after-free when caller
144                  * tries to release full stripe lock.
145                  *
146                  * No better way to resolve, but only to warn.
147                  */
148                 WARN_ON(!RB_EMPTY_ROOT(&cache->full_stripe_locks_root.root));
149                 kfree(cache->free_space_ctl);
150                 kfree(cache);
151         }
152 }
153
154 /*
155  * This adds the block group to the fs_info rb tree for the block group cache
156  */
157 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
158                                        struct btrfs_block_group *block_group)
159 {
160         struct rb_node **p;
161         struct rb_node *parent = NULL;
162         struct btrfs_block_group *cache;
163
164         spin_lock(&info->block_group_cache_lock);
165         p = &info->block_group_cache_tree.rb_node;
166
167         while (*p) {
168                 parent = *p;
169                 cache = rb_entry(parent, struct btrfs_block_group, cache_node);
170                 if (block_group->start < cache->start) {
171                         p = &(*p)->rb_left;
172                 } else if (block_group->start > cache->start) {
173                         p = &(*p)->rb_right;
174                 } else {
175                         spin_unlock(&info->block_group_cache_lock);
176                         return -EEXIST;
177                 }
178         }
179
180         rb_link_node(&block_group->cache_node, parent, p);
181         rb_insert_color(&block_group->cache_node,
182                         &info->block_group_cache_tree);
183
184         if (info->first_logical_byte > block_group->start)
185                 info->first_logical_byte = block_group->start;
186
187         spin_unlock(&info->block_group_cache_lock);
188
189         return 0;
190 }
191
192 /*
193  * This will return the block group at or after bytenr if contains is 0, else
194  * it will return the block group that contains the bytenr
195  */
196 static struct btrfs_block_group *block_group_cache_tree_search(
197                 struct btrfs_fs_info *info, u64 bytenr, int contains)
198 {
199         struct btrfs_block_group *cache, *ret = NULL;
200         struct rb_node *n;
201         u64 end, start;
202
203         spin_lock(&info->block_group_cache_lock);
204         n = info->block_group_cache_tree.rb_node;
205
206         while (n) {
207                 cache = rb_entry(n, struct btrfs_block_group, cache_node);
208                 end = cache->start + cache->length - 1;
209                 start = cache->start;
210
211                 if (bytenr < start) {
212                         if (!contains && (!ret || start < ret->start))
213                                 ret = cache;
214                         n = n->rb_left;
215                 } else if (bytenr > start) {
216                         if (contains && bytenr <= end) {
217                                 ret = cache;
218                                 break;
219                         }
220                         n = n->rb_right;
221                 } else {
222                         ret = cache;
223                         break;
224                 }
225         }
226         if (ret) {
227                 btrfs_get_block_group(ret);
228                 if (bytenr == 0 && info->first_logical_byte > ret->start)
229                         info->first_logical_byte = ret->start;
230         }
231         spin_unlock(&info->block_group_cache_lock);
232
233         return ret;
234 }
235
236 /*
237  * Return the block group that starts at or after bytenr
238  */
239 struct btrfs_block_group *btrfs_lookup_first_block_group(
240                 struct btrfs_fs_info *info, u64 bytenr)
241 {
242         return block_group_cache_tree_search(info, bytenr, 0);
243 }
244
245 /*
246  * Return the block group that contains the given bytenr
247  */
248 struct btrfs_block_group *btrfs_lookup_block_group(
249                 struct btrfs_fs_info *info, u64 bytenr)
250 {
251         return block_group_cache_tree_search(info, bytenr, 1);
252 }
253
254 struct btrfs_block_group *btrfs_next_block_group(
255                 struct btrfs_block_group *cache)
256 {
257         struct btrfs_fs_info *fs_info = cache->fs_info;
258         struct rb_node *node;
259
260         spin_lock(&fs_info->block_group_cache_lock);
261
262         /* If our block group was removed, we need a full search. */
263         if (RB_EMPTY_NODE(&cache->cache_node)) {
264                 const u64 next_bytenr = cache->start + cache->length;
265
266                 spin_unlock(&fs_info->block_group_cache_lock);
267                 btrfs_put_block_group(cache);
268                 cache = btrfs_lookup_first_block_group(fs_info, next_bytenr); return cache;
269         }
270         node = rb_next(&cache->cache_node);
271         btrfs_put_block_group(cache);
272         if (node) {
273                 cache = rb_entry(node, struct btrfs_block_group, cache_node);
274                 btrfs_get_block_group(cache);
275         } else
276                 cache = NULL;
277         spin_unlock(&fs_info->block_group_cache_lock);
278         return cache;
279 }
280
281 bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
282 {
283         struct btrfs_block_group *bg;
284         bool ret = true;
285
286         bg = btrfs_lookup_block_group(fs_info, bytenr);
287         if (!bg)
288                 return false;
289
290         spin_lock(&bg->lock);
291         if (bg->ro)
292                 ret = false;
293         else
294                 atomic_inc(&bg->nocow_writers);
295         spin_unlock(&bg->lock);
296
297         /* No put on block group, done by btrfs_dec_nocow_writers */
298         if (!ret)
299                 btrfs_put_block_group(bg);
300
301         return ret;
302 }
303
304 void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
305 {
306         struct btrfs_block_group *bg;
307
308         bg = btrfs_lookup_block_group(fs_info, bytenr);
309         ASSERT(bg);
310         if (atomic_dec_and_test(&bg->nocow_writers))
311                 wake_up_var(&bg->nocow_writers);
312         /*
313          * Once for our lookup and once for the lookup done by a previous call
314          * to btrfs_inc_nocow_writers()
315          */
316         btrfs_put_block_group(bg);
317         btrfs_put_block_group(bg);
318 }
319
320 void btrfs_wait_nocow_writers(struct btrfs_block_group *bg)
321 {
322         wait_var_event(&bg->nocow_writers, !atomic_read(&bg->nocow_writers));
323 }
324
325 void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
326                                         const u64 start)
327 {
328         struct btrfs_block_group *bg;
329
330         bg = btrfs_lookup_block_group(fs_info, start);
331         ASSERT(bg);
332         if (atomic_dec_and_test(&bg->reservations))
333                 wake_up_var(&bg->reservations);
334         btrfs_put_block_group(bg);
335 }
336
337 void btrfs_wait_block_group_reservations(struct btrfs_block_group *bg)
338 {
339         struct btrfs_space_info *space_info = bg->space_info;
340
341         ASSERT(bg->ro);
342
343         if (!(bg->flags & BTRFS_BLOCK_GROUP_DATA))
344                 return;
345
346         /*
347          * Our block group is read only but before we set it to read only,
348          * some task might have had allocated an extent from it already, but it
349          * has not yet created a respective ordered extent (and added it to a
350          * root's list of ordered extents).
351          * Therefore wait for any task currently allocating extents, since the
352          * block group's reservations counter is incremented while a read lock
353          * on the groups' semaphore is held and decremented after releasing
354          * the read access on that semaphore and creating the ordered extent.
355          */
356         down_write(&space_info->groups_sem);
357         up_write(&space_info->groups_sem);
358
359         wait_var_event(&bg->reservations, !atomic_read(&bg->reservations));
360 }
361
362 struct btrfs_caching_control *btrfs_get_caching_control(
363                 struct btrfs_block_group *cache)
364 {
365         struct btrfs_caching_control *ctl;
366
367         spin_lock(&cache->lock);
368         if (!cache->caching_ctl) {
369                 spin_unlock(&cache->lock);
370                 return NULL;
371         }
372
373         ctl = cache->caching_ctl;
374         refcount_inc(&ctl->count);
375         spin_unlock(&cache->lock);
376         return ctl;
377 }
378
379 void btrfs_put_caching_control(struct btrfs_caching_control *ctl)
380 {
381         if (refcount_dec_and_test(&ctl->count))
382                 kfree(ctl);
383 }
384
385 /*
386  * When we wait for progress in the block group caching, its because our
387  * allocation attempt failed at least once.  So, we must sleep and let some
388  * progress happen before we try again.
389  *
390  * This function will sleep at least once waiting for new free space to show
391  * up, and then it will check the block group free space numbers for our min
392  * num_bytes.  Another option is to have it go ahead and look in the rbtree for
393  * a free extent of a given size, but this is a good start.
394  *
395  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
396  * any of the information in this block group.
397  */
398 void btrfs_wait_block_group_cache_progress(struct btrfs_block_group *cache,
399                                            u64 num_bytes)
400 {
401         struct btrfs_caching_control *caching_ctl;
402
403         caching_ctl = btrfs_get_caching_control(cache);
404         if (!caching_ctl)
405                 return;
406
407         wait_event(caching_ctl->wait, btrfs_block_group_done(cache) ||
408                    (cache->free_space_ctl->free_space >= num_bytes));
409
410         btrfs_put_caching_control(caching_ctl);
411 }
412
413 int btrfs_wait_block_group_cache_done(struct btrfs_block_group *cache)
414 {
415         struct btrfs_caching_control *caching_ctl;
416         int ret = 0;
417
418         caching_ctl = btrfs_get_caching_control(cache);
419         if (!caching_ctl)
420                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
421
422         wait_event(caching_ctl->wait, btrfs_block_group_done(cache));
423         if (cache->cached == BTRFS_CACHE_ERROR)
424                 ret = -EIO;
425         btrfs_put_caching_control(caching_ctl);
426         return ret;
427 }
428
429 #ifdef CONFIG_BTRFS_DEBUG
430 static void fragment_free_space(struct btrfs_block_group *block_group)
431 {
432         struct btrfs_fs_info *fs_info = block_group->fs_info;
433         u64 start = block_group->start;
434         u64 len = block_group->length;
435         u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ?
436                 fs_info->nodesize : fs_info->sectorsize;
437         u64 step = chunk << 1;
438
439         while (len > chunk) {
440                 btrfs_remove_free_space(block_group, start, chunk);
441                 start += step;
442                 if (len < step)
443                         len = 0;
444                 else
445                         len -= step;
446         }
447 }
448 #endif
449
450 /*
451  * This is only called by btrfs_cache_block_group, since we could have freed
452  * extents we need to check the pinned_extents for any extents that can't be
453  * used yet since their free space will be released as soon as the transaction
454  * commits.
455  */
456 u64 add_new_free_space(struct btrfs_block_group *block_group, u64 start, u64 end)
457 {
458         struct btrfs_fs_info *info = block_group->fs_info;
459         u64 extent_start, extent_end, size, total_added = 0;
460         int ret;
461
462         while (start < end) {
463                 ret = find_first_extent_bit(info->pinned_extents, start,
464                                             &extent_start, &extent_end,
465                                             EXTENT_DIRTY | EXTENT_UPTODATE,
466                                             NULL);
467                 if (ret)
468                         break;
469
470                 if (extent_start <= start) {
471                         start = extent_end + 1;
472                 } else if (extent_start > start && extent_start < end) {
473                         size = extent_start - start;
474                         total_added += size;
475                         ret = btrfs_add_free_space_async_trimmed(block_group,
476                                                                  start, size);
477                         BUG_ON(ret); /* -ENOMEM or logic error */
478                         start = extent_end + 1;
479                 } else {
480                         break;
481                 }
482         }
483
484         if (start < end) {
485                 size = end - start;
486                 total_added += size;
487                 ret = btrfs_add_free_space_async_trimmed(block_group, start,
488                                                          size);
489                 BUG_ON(ret); /* -ENOMEM or logic error */
490         }
491
492         return total_added;
493 }
494
495 static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl)
496 {
497         struct btrfs_block_group *block_group = caching_ctl->block_group;
498         struct btrfs_fs_info *fs_info = block_group->fs_info;
499         struct btrfs_root *extent_root = fs_info->extent_root;
500         struct btrfs_path *path;
501         struct extent_buffer *leaf;
502         struct btrfs_key key;
503         u64 total_found = 0;
504         u64 last = 0;
505         u32 nritems;
506         int ret;
507         bool wakeup = true;
508
509         path = btrfs_alloc_path();
510         if (!path)
511                 return -ENOMEM;
512
513         last = max_t(u64, block_group->start, BTRFS_SUPER_INFO_OFFSET);
514
515 #ifdef CONFIG_BTRFS_DEBUG
516         /*
517          * If we're fragmenting we don't want to make anybody think we can
518          * allocate from this block group until we've had a chance to fragment
519          * the free space.
520          */
521         if (btrfs_should_fragment_free_space(block_group))
522                 wakeup = false;
523 #endif
524         /*
525          * We don't want to deadlock with somebody trying to allocate a new
526          * extent for the extent root while also trying to search the extent
527          * root to add free space.  So we skip locking and search the commit
528          * root, since its read-only
529          */
530         path->skip_locking = 1;
531         path->search_commit_root = 1;
532         path->reada = READA_FORWARD;
533
534         key.objectid = last;
535         key.offset = 0;
536         key.type = BTRFS_EXTENT_ITEM_KEY;
537
538 next:
539         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
540         if (ret < 0)
541                 goto out;
542
543         leaf = path->nodes[0];
544         nritems = btrfs_header_nritems(leaf);
545
546         while (1) {
547                 if (btrfs_fs_closing(fs_info) > 1) {
548                         last = (u64)-1;
549                         break;
550                 }
551
552                 if (path->slots[0] < nritems) {
553                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
554                 } else {
555                         ret = btrfs_find_next_key(extent_root, path, &key, 0, 0);
556                         if (ret)
557                                 break;
558
559                         if (need_resched() ||
560                             rwsem_is_contended(&fs_info->commit_root_sem)) {
561                                 if (wakeup)
562                                         caching_ctl->progress = last;
563                                 btrfs_release_path(path);
564                                 up_read(&fs_info->commit_root_sem);
565                                 mutex_unlock(&caching_ctl->mutex);
566                                 cond_resched();
567                                 mutex_lock(&caching_ctl->mutex);
568                                 down_read(&fs_info->commit_root_sem);
569                                 goto next;
570                         }
571
572                         ret = btrfs_next_leaf(extent_root, path);
573                         if (ret < 0)
574                                 goto out;
575                         if (ret)
576                                 break;
577                         leaf = path->nodes[0];
578                         nritems = btrfs_header_nritems(leaf);
579                         continue;
580                 }
581
582                 if (key.objectid < last) {
583                         key.objectid = last;
584                         key.offset = 0;
585                         key.type = BTRFS_EXTENT_ITEM_KEY;
586
587                         if (wakeup)
588                                 caching_ctl->progress = last;
589                         btrfs_release_path(path);
590                         goto next;
591                 }
592
593                 if (key.objectid < block_group->start) {
594                         path->slots[0]++;
595                         continue;
596                 }
597
598                 if (key.objectid >= block_group->start + block_group->length)
599                         break;
600
601                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
602                     key.type == BTRFS_METADATA_ITEM_KEY) {
603                         total_found += add_new_free_space(block_group, last,
604                                                           key.objectid);
605                         if (key.type == BTRFS_METADATA_ITEM_KEY)
606                                 last = key.objectid +
607                                         fs_info->nodesize;
608                         else
609                                 last = key.objectid + key.offset;
610
611                         if (total_found > CACHING_CTL_WAKE_UP) {
612                                 total_found = 0;
613                                 if (wakeup)
614                                         wake_up(&caching_ctl->wait);
615                         }
616                 }
617                 path->slots[0]++;
618         }
619         ret = 0;
620
621         total_found += add_new_free_space(block_group, last,
622                                 block_group->start + block_group->length);
623         caching_ctl->progress = (u64)-1;
624
625 out:
626         btrfs_free_path(path);
627         return ret;
628 }
629
630 static noinline void caching_thread(struct btrfs_work *work)
631 {
632         struct btrfs_block_group *block_group;
633         struct btrfs_fs_info *fs_info;
634         struct btrfs_caching_control *caching_ctl;
635         int ret;
636
637         caching_ctl = container_of(work, struct btrfs_caching_control, work);
638         block_group = caching_ctl->block_group;
639         fs_info = block_group->fs_info;
640
641         mutex_lock(&caching_ctl->mutex);
642         down_read(&fs_info->commit_root_sem);
643
644         if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
645                 ret = load_free_space_tree(caching_ctl);
646         else
647                 ret = load_extent_tree_free(caching_ctl);
648
649         spin_lock(&block_group->lock);
650         block_group->caching_ctl = NULL;
651         block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED;
652         spin_unlock(&block_group->lock);
653
654 #ifdef CONFIG_BTRFS_DEBUG
655         if (btrfs_should_fragment_free_space(block_group)) {
656                 u64 bytes_used;
657
658                 spin_lock(&block_group->space_info->lock);
659                 spin_lock(&block_group->lock);
660                 bytes_used = block_group->length - block_group->used;
661                 block_group->space_info->bytes_used += bytes_used >> 1;
662                 spin_unlock(&block_group->lock);
663                 spin_unlock(&block_group->space_info->lock);
664                 fragment_free_space(block_group);
665         }
666 #endif
667
668         caching_ctl->progress = (u64)-1;
669
670         up_read(&fs_info->commit_root_sem);
671         btrfs_free_excluded_extents(block_group);
672         mutex_unlock(&caching_ctl->mutex);
673
674         wake_up(&caching_ctl->wait);
675
676         btrfs_put_caching_control(caching_ctl);
677         btrfs_put_block_group(block_group);
678 }
679
680 int btrfs_cache_block_group(struct btrfs_block_group *cache, int load_cache_only)
681 {
682         DEFINE_WAIT(wait);
683         struct btrfs_fs_info *fs_info = cache->fs_info;
684         struct btrfs_caching_control *caching_ctl;
685         int ret = 0;
686
687         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
688         if (!caching_ctl)
689                 return -ENOMEM;
690
691         INIT_LIST_HEAD(&caching_ctl->list);
692         mutex_init(&caching_ctl->mutex);
693         init_waitqueue_head(&caching_ctl->wait);
694         caching_ctl->block_group = cache;
695         caching_ctl->progress = cache->start;
696         refcount_set(&caching_ctl->count, 1);
697         btrfs_init_work(&caching_ctl->work, caching_thread, NULL, NULL);
698
699         spin_lock(&cache->lock);
700         /*
701          * This should be a rare occasion, but this could happen I think in the
702          * case where one thread starts to load the space cache info, and then
703          * some other thread starts a transaction commit which tries to do an
704          * allocation while the other thread is still loading the space cache
705          * info.  The previous loop should have kept us from choosing this block
706          * group, but if we've moved to the state where we will wait on caching
707          * block groups we need to first check if we're doing a fast load here,
708          * so we can wait for it to finish, otherwise we could end up allocating
709          * from a block group who's cache gets evicted for one reason or
710          * another.
711          */
712         while (cache->cached == BTRFS_CACHE_FAST) {
713                 struct btrfs_caching_control *ctl;
714
715                 ctl = cache->caching_ctl;
716                 refcount_inc(&ctl->count);
717                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
718                 spin_unlock(&cache->lock);
719
720                 schedule();
721
722                 finish_wait(&ctl->wait, &wait);
723                 btrfs_put_caching_control(ctl);
724                 spin_lock(&cache->lock);
725         }
726
727         if (cache->cached != BTRFS_CACHE_NO) {
728                 spin_unlock(&cache->lock);
729                 kfree(caching_ctl);
730                 return 0;
731         }
732         WARN_ON(cache->caching_ctl);
733         cache->caching_ctl = caching_ctl;
734         cache->cached = BTRFS_CACHE_FAST;
735         spin_unlock(&cache->lock);
736
737         if (btrfs_test_opt(fs_info, SPACE_CACHE)) {
738                 mutex_lock(&caching_ctl->mutex);
739                 ret = load_free_space_cache(cache);
740
741                 spin_lock(&cache->lock);
742                 if (ret == 1) {
743                         cache->caching_ctl = NULL;
744                         cache->cached = BTRFS_CACHE_FINISHED;
745                         cache->last_byte_to_unpin = (u64)-1;
746                         caching_ctl->progress = (u64)-1;
747                 } else {
748                         if (load_cache_only) {
749                                 cache->caching_ctl = NULL;
750                                 cache->cached = BTRFS_CACHE_NO;
751                         } else {
752                                 cache->cached = BTRFS_CACHE_STARTED;
753                                 cache->has_caching_ctl = 1;
754                         }
755                 }
756                 spin_unlock(&cache->lock);
757 #ifdef CONFIG_BTRFS_DEBUG
758                 if (ret == 1 &&
759                     btrfs_should_fragment_free_space(cache)) {
760                         u64 bytes_used;
761
762                         spin_lock(&cache->space_info->lock);
763                         spin_lock(&cache->lock);
764                         bytes_used = cache->length - cache->used;
765                         cache->space_info->bytes_used += bytes_used >> 1;
766                         spin_unlock(&cache->lock);
767                         spin_unlock(&cache->space_info->lock);
768                         fragment_free_space(cache);
769                 }
770 #endif
771                 mutex_unlock(&caching_ctl->mutex);
772
773                 wake_up(&caching_ctl->wait);
774                 if (ret == 1) {
775                         btrfs_put_caching_control(caching_ctl);
776                         btrfs_free_excluded_extents(cache);
777                         return 0;
778                 }
779         } else {
780                 /*
781                  * We're either using the free space tree or no caching at all.
782                  * Set cached to the appropriate value and wakeup any waiters.
783                  */
784                 spin_lock(&cache->lock);
785                 if (load_cache_only) {
786                         cache->caching_ctl = NULL;
787                         cache->cached = BTRFS_CACHE_NO;
788                 } else {
789                         cache->cached = BTRFS_CACHE_STARTED;
790                         cache->has_caching_ctl = 1;
791                 }
792                 spin_unlock(&cache->lock);
793                 wake_up(&caching_ctl->wait);
794         }
795
796         if (load_cache_only) {
797                 btrfs_put_caching_control(caching_ctl);
798                 return 0;
799         }
800
801         down_write(&fs_info->commit_root_sem);
802         refcount_inc(&caching_ctl->count);
803         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
804         up_write(&fs_info->commit_root_sem);
805
806         btrfs_get_block_group(cache);
807
808         btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
809
810         return ret;
811 }
812
813 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
814 {
815         u64 extra_flags = chunk_to_extended(flags) &
816                                 BTRFS_EXTENDED_PROFILE_MASK;
817
818         write_seqlock(&fs_info->profiles_lock);
819         if (flags & BTRFS_BLOCK_GROUP_DATA)
820                 fs_info->avail_data_alloc_bits &= ~extra_flags;
821         if (flags & BTRFS_BLOCK_GROUP_METADATA)
822                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
823         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
824                 fs_info->avail_system_alloc_bits &= ~extra_flags;
825         write_sequnlock(&fs_info->profiles_lock);
826 }
827
828 /*
829  * Clear incompat bits for the following feature(s):
830  *
831  * - RAID56 - in case there's neither RAID5 nor RAID6 profile block group
832  *            in the whole filesystem
833  *
834  * - RAID1C34 - same as above for RAID1C3 and RAID1C4 block groups
835  */
836 static void clear_incompat_bg_bits(struct btrfs_fs_info *fs_info, u64 flags)
837 {
838         bool found_raid56 = false;
839         bool found_raid1c34 = false;
840
841         if ((flags & BTRFS_BLOCK_GROUP_RAID56_MASK) ||
842             (flags & BTRFS_BLOCK_GROUP_RAID1C3) ||
843             (flags & BTRFS_BLOCK_GROUP_RAID1C4)) {
844                 struct list_head *head = &fs_info->space_info;
845                 struct btrfs_space_info *sinfo;
846
847                 list_for_each_entry_rcu(sinfo, head, list) {
848                         down_read(&sinfo->groups_sem);
849                         if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID5]))
850                                 found_raid56 = true;
851                         if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID6]))
852                                 found_raid56 = true;
853                         if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID1C3]))
854                                 found_raid1c34 = true;
855                         if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID1C4]))
856                                 found_raid1c34 = true;
857                         up_read(&sinfo->groups_sem);
858                 }
859                 if (found_raid56)
860                         btrfs_clear_fs_incompat(fs_info, RAID56);
861                 if (found_raid1c34)
862                         btrfs_clear_fs_incompat(fs_info, RAID1C34);
863         }
864 }
865
866 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
867                              u64 group_start, struct extent_map *em)
868 {
869         struct btrfs_fs_info *fs_info = trans->fs_info;
870         struct btrfs_root *root = fs_info->extent_root;
871         struct btrfs_path *path;
872         struct btrfs_block_group *block_group;
873         struct btrfs_free_cluster *cluster;
874         struct btrfs_root *tree_root = fs_info->tree_root;
875         struct btrfs_key key;
876         struct inode *inode;
877         struct kobject *kobj = NULL;
878         int ret;
879         int index;
880         int factor;
881         struct btrfs_caching_control *caching_ctl = NULL;
882         bool remove_em;
883         bool remove_rsv = false;
884
885         block_group = btrfs_lookup_block_group(fs_info, group_start);
886         BUG_ON(!block_group);
887         BUG_ON(!block_group->ro);
888
889         trace_btrfs_remove_block_group(block_group);
890         /*
891          * Free the reserved super bytes from this block group before
892          * remove it.
893          */
894         btrfs_free_excluded_extents(block_group);
895         btrfs_free_ref_tree_range(fs_info, block_group->start,
896                                   block_group->length);
897
898         index = btrfs_bg_flags_to_raid_index(block_group->flags);
899         factor = btrfs_bg_type_to_factor(block_group->flags);
900
901         /* make sure this block group isn't part of an allocation cluster */
902         cluster = &fs_info->data_alloc_cluster;
903         spin_lock(&cluster->refill_lock);
904         btrfs_return_cluster_to_free_space(block_group, cluster);
905         spin_unlock(&cluster->refill_lock);
906
907         /*
908          * make sure this block group isn't part of a metadata
909          * allocation cluster
910          */
911         cluster = &fs_info->meta_alloc_cluster;
912         spin_lock(&cluster->refill_lock);
913         btrfs_return_cluster_to_free_space(block_group, cluster);
914         spin_unlock(&cluster->refill_lock);
915
916         path = btrfs_alloc_path();
917         if (!path) {
918                 ret = -ENOMEM;
919                 goto out;
920         }
921
922         /*
923          * get the inode first so any iput calls done for the io_list
924          * aren't the final iput (no unlinks allowed now)
925          */
926         inode = lookup_free_space_inode(block_group, path);
927
928         mutex_lock(&trans->transaction->cache_write_mutex);
929         /*
930          * Make sure our free space cache IO is done before removing the
931          * free space inode
932          */
933         spin_lock(&trans->transaction->dirty_bgs_lock);
934         if (!list_empty(&block_group->io_list)) {
935                 list_del_init(&block_group->io_list);
936
937                 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
938
939                 spin_unlock(&trans->transaction->dirty_bgs_lock);
940                 btrfs_wait_cache_io(trans, block_group, path);
941                 btrfs_put_block_group(block_group);
942                 spin_lock(&trans->transaction->dirty_bgs_lock);
943         }
944
945         if (!list_empty(&block_group->dirty_list)) {
946                 list_del_init(&block_group->dirty_list);
947                 remove_rsv = true;
948                 btrfs_put_block_group(block_group);
949         }
950         spin_unlock(&trans->transaction->dirty_bgs_lock);
951         mutex_unlock(&trans->transaction->cache_write_mutex);
952
953         if (!IS_ERR(inode)) {
954                 ret = btrfs_orphan_add(trans, BTRFS_I(inode));
955                 if (ret) {
956                         btrfs_add_delayed_iput(inode);
957                         goto out;
958                 }
959                 clear_nlink(inode);
960                 /* One for the block groups ref */
961                 spin_lock(&block_group->lock);
962                 if (block_group->iref) {
963                         block_group->iref = 0;
964                         block_group->inode = NULL;
965                         spin_unlock(&block_group->lock);
966                         iput(inode);
967                 } else {
968                         spin_unlock(&block_group->lock);
969                 }
970                 /* One for our lookup ref */
971                 btrfs_add_delayed_iput(inode);
972         }
973
974         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
975         key.type = 0;
976         key.offset = block_group->start;
977
978         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
979         if (ret < 0)
980                 goto out;
981         if (ret > 0)
982                 btrfs_release_path(path);
983         if (ret == 0) {
984                 ret = btrfs_del_item(trans, tree_root, path);
985                 if (ret)
986                         goto out;
987                 btrfs_release_path(path);
988         }
989
990         spin_lock(&fs_info->block_group_cache_lock);
991         rb_erase(&block_group->cache_node,
992                  &fs_info->block_group_cache_tree);
993         RB_CLEAR_NODE(&block_group->cache_node);
994
995         if (fs_info->first_logical_byte == block_group->start)
996                 fs_info->first_logical_byte = (u64)-1;
997         spin_unlock(&fs_info->block_group_cache_lock);
998
999         down_write(&block_group->space_info->groups_sem);
1000         /*
1001          * we must use list_del_init so people can check to see if they
1002          * are still on the list after taking the semaphore
1003          */
1004         list_del_init(&block_group->list);
1005         if (list_empty(&block_group->space_info->block_groups[index])) {
1006                 kobj = block_group->space_info->block_group_kobjs[index];
1007                 block_group->space_info->block_group_kobjs[index] = NULL;
1008                 clear_avail_alloc_bits(fs_info, block_group->flags);
1009         }
1010         up_write(&block_group->space_info->groups_sem);
1011         clear_incompat_bg_bits(fs_info, block_group->flags);
1012         if (kobj) {
1013                 kobject_del(kobj);
1014                 kobject_put(kobj);
1015         }
1016
1017         if (block_group->has_caching_ctl)
1018                 caching_ctl = btrfs_get_caching_control(block_group);
1019         if (block_group->cached == BTRFS_CACHE_STARTED)
1020                 btrfs_wait_block_group_cache_done(block_group);
1021         if (block_group->has_caching_ctl) {
1022                 down_write(&fs_info->commit_root_sem);
1023                 if (!caching_ctl) {
1024                         struct btrfs_caching_control *ctl;
1025
1026                         list_for_each_entry(ctl,
1027                                     &fs_info->caching_block_groups, list)
1028                                 if (ctl->block_group == block_group) {
1029                                         caching_ctl = ctl;
1030                                         refcount_inc(&caching_ctl->count);
1031                                         break;
1032                                 }
1033                 }
1034                 if (caching_ctl)
1035                         list_del_init(&caching_ctl->list);
1036                 up_write(&fs_info->commit_root_sem);
1037                 if (caching_ctl) {
1038                         /* Once for the caching bgs list and once for us. */
1039                         btrfs_put_caching_control(caching_ctl);
1040                         btrfs_put_caching_control(caching_ctl);
1041                 }
1042         }
1043
1044         spin_lock(&trans->transaction->dirty_bgs_lock);
1045         WARN_ON(!list_empty(&block_group->dirty_list));
1046         WARN_ON(!list_empty(&block_group->io_list));
1047         spin_unlock(&trans->transaction->dirty_bgs_lock);
1048
1049         btrfs_remove_free_space_cache(block_group);
1050
1051         spin_lock(&block_group->space_info->lock);
1052         list_del_init(&block_group->ro_list);
1053
1054         if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
1055                 WARN_ON(block_group->space_info->total_bytes
1056                         < block_group->length);
1057                 WARN_ON(block_group->space_info->bytes_readonly
1058                         < block_group->length);
1059                 WARN_ON(block_group->space_info->disk_total
1060                         < block_group->length * factor);
1061         }
1062         block_group->space_info->total_bytes -= block_group->length;
1063         block_group->space_info->bytes_readonly -= block_group->length;
1064         block_group->space_info->disk_total -= block_group->length * factor;
1065
1066         spin_unlock(&block_group->space_info->lock);
1067
1068         key.objectid = block_group->start;
1069         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
1070         key.offset = block_group->length;
1071
1072         mutex_lock(&fs_info->chunk_mutex);
1073         spin_lock(&block_group->lock);
1074         block_group->removed = 1;
1075         /*
1076          * At this point trimming can't start on this block group, because we
1077          * removed the block group from the tree fs_info->block_group_cache_tree
1078          * so no one can't find it anymore and even if someone already got this
1079          * block group before we removed it from the rbtree, they have already
1080          * incremented block_group->trimming - if they didn't, they won't find
1081          * any free space entries because we already removed them all when we
1082          * called btrfs_remove_free_space_cache().
1083          *
1084          * And we must not remove the extent map from the fs_info->mapping_tree
1085          * to prevent the same logical address range and physical device space
1086          * ranges from being reused for a new block group. This is because our
1087          * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
1088          * completely transactionless, so while it is trimming a range the
1089          * currently running transaction might finish and a new one start,
1090          * allowing for new block groups to be created that can reuse the same
1091          * physical device locations unless we take this special care.
1092          *
1093          * There may also be an implicit trim operation if the file system
1094          * is mounted with -odiscard. The same protections must remain
1095          * in place until the extents have been discarded completely when
1096          * the transaction commit has completed.
1097          */
1098         remove_em = (atomic_read(&block_group->trimming) == 0);
1099         spin_unlock(&block_group->lock);
1100
1101         mutex_unlock(&fs_info->chunk_mutex);
1102
1103         ret = remove_block_group_free_space(trans, block_group);
1104         if (ret)
1105                 goto out;
1106
1107         btrfs_put_block_group(block_group);
1108         btrfs_put_block_group(block_group);
1109
1110         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1111         if (ret > 0)
1112                 ret = -EIO;
1113         if (ret < 0)
1114                 goto out;
1115
1116         ret = btrfs_del_item(trans, root, path);
1117         if (ret)
1118                 goto out;
1119
1120         if (remove_em) {
1121                 struct extent_map_tree *em_tree;
1122
1123                 em_tree = &fs_info->mapping_tree;
1124                 write_lock(&em_tree->lock);
1125                 remove_extent_mapping(em_tree, em);
1126                 write_unlock(&em_tree->lock);
1127                 /* once for the tree */
1128                 free_extent_map(em);
1129         }
1130 out:
1131         if (remove_rsv)
1132                 btrfs_delayed_refs_rsv_release(fs_info, 1);
1133         btrfs_free_path(path);
1134         return ret;
1135 }
1136
1137 struct btrfs_trans_handle *btrfs_start_trans_remove_block_group(
1138                 struct btrfs_fs_info *fs_info, const u64 chunk_offset)
1139 {
1140         struct extent_map_tree *em_tree = &fs_info->mapping_tree;
1141         struct extent_map *em;
1142         struct map_lookup *map;
1143         unsigned int num_items;
1144
1145         read_lock(&em_tree->lock);
1146         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
1147         read_unlock(&em_tree->lock);
1148         ASSERT(em && em->start == chunk_offset);
1149
1150         /*
1151          * We need to reserve 3 + N units from the metadata space info in order
1152          * to remove a block group (done at btrfs_remove_chunk() and at
1153          * btrfs_remove_block_group()), which are used for:
1154          *
1155          * 1 unit for adding the free space inode's orphan (located in the tree
1156          * of tree roots).
1157          * 1 unit for deleting the block group item (located in the extent
1158          * tree).
1159          * 1 unit for deleting the free space item (located in tree of tree
1160          * roots).
1161          * N units for deleting N device extent items corresponding to each
1162          * stripe (located in the device tree).
1163          *
1164          * In order to remove a block group we also need to reserve units in the
1165          * system space info in order to update the chunk tree (update one or
1166          * more device items and remove one chunk item), but this is done at
1167          * btrfs_remove_chunk() through a call to check_system_chunk().
1168          */
1169         map = em->map_lookup;
1170         num_items = 3 + map->num_stripes;
1171         free_extent_map(em);
1172
1173         return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
1174                                                            num_items, 1);
1175 }
1176
1177 /*
1178  * Mark block group @cache read-only, so later write won't happen to block
1179  * group @cache.
1180  *
1181  * If @force is not set, this function will only mark the block group readonly
1182  * if we have enough free space (1M) in other metadata/system block groups.
1183  * If @force is not set, this function will mark the block group readonly
1184  * without checking free space.
1185  *
1186  * NOTE: This function doesn't care if other block groups can contain all the
1187  * data in this block group. That check should be done by relocation routine,
1188  * not this function.
1189  */
1190 static int inc_block_group_ro(struct btrfs_block_group *cache, int force)
1191 {
1192         struct btrfs_space_info *sinfo = cache->space_info;
1193         u64 num_bytes;
1194         u64 sinfo_used;
1195         int ret = -ENOSPC;
1196
1197         spin_lock(&sinfo->lock);
1198         spin_lock(&cache->lock);
1199
1200         if (cache->ro) {
1201                 cache->ro++;
1202                 ret = 0;
1203                 goto out;
1204         }
1205
1206         num_bytes = cache->length - cache->reserved - cache->pinned -
1207                     cache->bytes_super - cache->used;
1208         sinfo_used = btrfs_space_info_used(sinfo, true);
1209
1210         /*
1211          * sinfo_used + num_bytes should always <= sinfo->total_bytes.
1212          *
1213          * Here we make sure if we mark this bg RO, we still have enough
1214          * free space as buffer.
1215          */
1216         if (sinfo_used + num_bytes <= sinfo->total_bytes) {
1217                 sinfo->bytes_readonly += num_bytes;
1218                 cache->ro++;
1219                 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
1220                 ret = 0;
1221         }
1222 out:
1223         spin_unlock(&cache->lock);
1224         spin_unlock(&sinfo->lock);
1225         if (ret == -ENOSPC && btrfs_test_opt(cache->fs_info, ENOSPC_DEBUG)) {
1226                 btrfs_info(cache->fs_info,
1227                         "unable to make block group %llu ro", cache->start);
1228                 btrfs_info(cache->fs_info,
1229                         "sinfo_used=%llu bg_num_bytes=%llu",
1230                         sinfo_used, num_bytes);
1231                 btrfs_dump_space_info(cache->fs_info, cache->space_info, 0, 0);
1232         }
1233         return ret;
1234 }
1235
1236 /*
1237  * Process the unused_bgs list and remove any that don't have any allocated
1238  * space inside of them.
1239  */
1240 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
1241 {
1242         struct btrfs_block_group *block_group;
1243         struct btrfs_space_info *space_info;
1244         struct btrfs_trans_handle *trans;
1245         const bool async_trim_enabled = btrfs_test_opt(fs_info, DISCARD_ASYNC);
1246         int ret = 0;
1247
1248         if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
1249                 return;
1250
1251         spin_lock(&fs_info->unused_bgs_lock);
1252         while (!list_empty(&fs_info->unused_bgs)) {
1253                 u64 start, end;
1254                 int trimming;
1255
1256                 block_group = list_first_entry(&fs_info->unused_bgs,
1257                                                struct btrfs_block_group,
1258                                                bg_list);
1259                 list_del_init(&block_group->bg_list);
1260
1261                 space_info = block_group->space_info;
1262
1263                 if (ret || btrfs_mixed_space_info(space_info)) {
1264                         btrfs_put_block_group(block_group);
1265                         continue;
1266                 }
1267                 spin_unlock(&fs_info->unused_bgs_lock);
1268
1269                 btrfs_discard_cancel_work(&fs_info->discard_ctl, block_group);
1270
1271                 mutex_lock(&fs_info->delete_unused_bgs_mutex);
1272
1273                 /* Don't want to race with allocators so take the groups_sem */
1274                 down_write(&space_info->groups_sem);
1275
1276                 /*
1277                  * Async discard moves the final block group discard to be prior
1278                  * to the unused_bgs code path.  Therefore, if it's not fully
1279                  * trimmed, punt it back to the async discard lists.
1280                  */
1281                 if (btrfs_test_opt(fs_info, DISCARD_ASYNC) &&
1282                     !btrfs_is_free_space_trimmed(block_group)) {
1283                         trace_btrfs_skip_unused_block_group(block_group);
1284                         up_write(&space_info->groups_sem);
1285                         /* Requeue if we failed because of async discard */
1286                         btrfs_discard_queue_work(&fs_info->discard_ctl,
1287                                                  block_group);
1288                         goto next;
1289                 }
1290
1291                 spin_lock(&block_group->lock);
1292                 if (block_group->reserved || block_group->pinned ||
1293                     block_group->used || block_group->ro ||
1294                     list_is_singular(&block_group->list)) {
1295                         /*
1296                          * We want to bail if we made new allocations or have
1297                          * outstanding allocations in this block group.  We do
1298                          * the ro check in case balance is currently acting on
1299                          * this block group.
1300                          */
1301                         trace_btrfs_skip_unused_block_group(block_group);
1302                         spin_unlock(&block_group->lock);
1303                         up_write(&space_info->groups_sem);
1304                         goto next;
1305                 }
1306                 spin_unlock(&block_group->lock);
1307
1308                 /* We don't want to force the issue, only flip if it's ok. */
1309                 ret = inc_block_group_ro(block_group, 0);
1310                 up_write(&space_info->groups_sem);
1311                 if (ret < 0) {
1312                         ret = 0;
1313                         goto next;
1314                 }
1315
1316                 /*
1317                  * Want to do this before we do anything else so we can recover
1318                  * properly if we fail to join the transaction.
1319                  */
1320                 trans = btrfs_start_trans_remove_block_group(fs_info,
1321                                                      block_group->start);
1322                 if (IS_ERR(trans)) {
1323                         btrfs_dec_block_group_ro(block_group);
1324                         ret = PTR_ERR(trans);
1325                         goto next;
1326                 }
1327
1328                 /*
1329                  * We could have pending pinned extents for this block group,
1330                  * just delete them, we don't care about them anymore.
1331                  */
1332                 start = block_group->start;
1333                 end = start + block_group->length - 1;
1334                 /*
1335                  * Hold the unused_bg_unpin_mutex lock to avoid racing with
1336                  * btrfs_finish_extent_commit(). If we are at transaction N,
1337                  * another task might be running finish_extent_commit() for the
1338                  * previous transaction N - 1, and have seen a range belonging
1339                  * to the block group in freed_extents[] before we were able to
1340                  * clear the whole block group range from freed_extents[]. This
1341                  * means that task can lookup for the block group after we
1342                  * unpinned it from freed_extents[] and removed it, leading to
1343                  * a BUG_ON() at btrfs_unpin_extent_range().
1344                  */
1345                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
1346                 ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
1347                                   EXTENT_DIRTY);
1348                 if (ret) {
1349                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
1350                         btrfs_dec_block_group_ro(block_group);
1351                         goto end_trans;
1352                 }
1353                 ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
1354                                   EXTENT_DIRTY);
1355                 if (ret) {
1356                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
1357                         btrfs_dec_block_group_ro(block_group);
1358                         goto end_trans;
1359                 }
1360                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
1361
1362                 /*
1363                  * At this point, the block_group is read only and should fail
1364                  * new allocations.  However, btrfs_finish_extent_commit() can
1365                  * cause this block_group to be placed back on the discard
1366                  * lists because now the block_group isn't fully discarded.
1367                  * Bail here and try again later after discarding everything.
1368                  */
1369                 spin_lock(&fs_info->discard_ctl.lock);
1370                 if (!list_empty(&block_group->discard_list)) {
1371                         spin_unlock(&fs_info->discard_ctl.lock);
1372                         btrfs_dec_block_group_ro(block_group);
1373                         btrfs_discard_queue_work(&fs_info->discard_ctl,
1374                                                  block_group);
1375                         goto end_trans;
1376                 }
1377                 spin_unlock(&fs_info->discard_ctl.lock);
1378
1379                 /* Reset pinned so btrfs_put_block_group doesn't complain */
1380                 spin_lock(&space_info->lock);
1381                 spin_lock(&block_group->lock);
1382
1383                 btrfs_space_info_update_bytes_pinned(fs_info, space_info,
1384                                                      -block_group->pinned);
1385                 space_info->bytes_readonly += block_group->pinned;
1386                 percpu_counter_add_batch(&space_info->total_bytes_pinned,
1387                                    -block_group->pinned,
1388                                    BTRFS_TOTAL_BYTES_PINNED_BATCH);
1389                 block_group->pinned = 0;
1390
1391                 spin_unlock(&block_group->lock);
1392                 spin_unlock(&space_info->lock);
1393
1394                 /*
1395                  * The normal path here is an unused block group is passed here,
1396                  * then trimming is handled in the transaction commit path.
1397                  * Async discard interposes before this to do the trimming
1398                  * before coming down the unused block group path as trimming
1399                  * will no longer be done later in the transaction commit path.
1400                  */
1401                 if (!async_trim_enabled && btrfs_test_opt(fs_info, DISCARD_ASYNC))
1402                         goto flip_async;
1403
1404                 /* DISCARD can flip during remount */
1405                 trimming = btrfs_test_opt(fs_info, DISCARD_SYNC);
1406
1407                 /* Implicit trim during transaction commit. */
1408                 if (trimming)
1409                         btrfs_get_block_group_trimming(block_group);
1410
1411                 /*
1412                  * Btrfs_remove_chunk will abort the transaction if things go
1413                  * horribly wrong.
1414                  */
1415                 ret = btrfs_remove_chunk(trans, block_group->start);
1416
1417                 if (ret) {
1418                         if (trimming)
1419                                 btrfs_put_block_group_trimming(block_group);
1420                         goto end_trans;
1421                 }
1422
1423                 /*
1424                  * If we're not mounted with -odiscard, we can just forget
1425                  * about this block group. Otherwise we'll need to wait
1426                  * until transaction commit to do the actual discard.
1427                  */
1428                 if (trimming) {
1429                         spin_lock(&fs_info->unused_bgs_lock);
1430                         /*
1431                          * A concurrent scrub might have added us to the list
1432                          * fs_info->unused_bgs, so use a list_move operation
1433                          * to add the block group to the deleted_bgs list.
1434                          */
1435                         list_move(&block_group->bg_list,
1436                                   &trans->transaction->deleted_bgs);
1437                         spin_unlock(&fs_info->unused_bgs_lock);
1438                         btrfs_get_block_group(block_group);
1439                 }
1440 end_trans:
1441                 btrfs_end_transaction(trans);
1442 next:
1443                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
1444                 btrfs_put_block_group(block_group);
1445                 spin_lock(&fs_info->unused_bgs_lock);
1446         }
1447         spin_unlock(&fs_info->unused_bgs_lock);
1448         return;
1449
1450 flip_async:
1451         btrfs_end_transaction(trans);
1452         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
1453         btrfs_put_block_group(block_group);
1454         btrfs_discard_punt_unused_bgs_list(fs_info);
1455 }
1456
1457 void btrfs_mark_bg_unused(struct btrfs_block_group *bg)
1458 {
1459         struct btrfs_fs_info *fs_info = bg->fs_info;
1460
1461         spin_lock(&fs_info->unused_bgs_lock);
1462         if (list_empty(&bg->bg_list)) {
1463                 btrfs_get_block_group(bg);
1464                 trace_btrfs_add_unused_block_group(bg);
1465                 list_add_tail(&bg->bg_list, &fs_info->unused_bgs);
1466         }
1467         spin_unlock(&fs_info->unused_bgs_lock);
1468 }
1469
1470 static int find_first_block_group(struct btrfs_fs_info *fs_info,
1471                                   struct btrfs_path *path,
1472                                   struct btrfs_key *key)
1473 {
1474         struct btrfs_root *root = fs_info->extent_root;
1475         int ret = 0;
1476         struct btrfs_key found_key;
1477         struct extent_buffer *leaf;
1478         struct btrfs_block_group_item bg;
1479         u64 flags;
1480         int slot;
1481
1482         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
1483         if (ret < 0)
1484                 goto out;
1485
1486         while (1) {
1487                 slot = path->slots[0];
1488                 leaf = path->nodes[0];
1489                 if (slot >= btrfs_header_nritems(leaf)) {
1490                         ret = btrfs_next_leaf(root, path);
1491                         if (ret == 0)
1492                                 continue;
1493                         if (ret < 0)
1494                                 goto out;
1495                         break;
1496                 }
1497                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
1498
1499                 if (found_key.objectid >= key->objectid &&
1500                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
1501                         struct extent_map_tree *em_tree;
1502                         struct extent_map *em;
1503
1504                         em_tree = &root->fs_info->mapping_tree;
1505                         read_lock(&em_tree->lock);
1506                         em = lookup_extent_mapping(em_tree, found_key.objectid,
1507                                                    found_key.offset);
1508                         read_unlock(&em_tree->lock);
1509                         if (!em) {
1510                                 btrfs_err(fs_info,
1511                         "logical %llu len %llu found bg but no related chunk",
1512                                           found_key.objectid, found_key.offset);
1513                                 ret = -ENOENT;
1514                         } else if (em->start != found_key.objectid ||
1515                                    em->len != found_key.offset) {
1516                                 btrfs_err(fs_info,
1517                 "block group %llu len %llu mismatch with chunk %llu len %llu",
1518                                           found_key.objectid, found_key.offset,
1519                                           em->start, em->len);
1520                                 ret = -EUCLEAN;
1521                         } else {
1522                                 read_extent_buffer(leaf, &bg,
1523                                         btrfs_item_ptr_offset(leaf, slot),
1524                                         sizeof(bg));
1525                                 flags = btrfs_stack_block_group_flags(&bg) &
1526                                         BTRFS_BLOCK_GROUP_TYPE_MASK;
1527
1528                                 if (flags != (em->map_lookup->type &
1529                                               BTRFS_BLOCK_GROUP_TYPE_MASK)) {
1530                                         btrfs_err(fs_info,
1531 "block group %llu len %llu type flags 0x%llx mismatch with chunk type flags 0x%llx",
1532                                                 found_key.objectid,
1533                                                 found_key.offset, flags,
1534                                                 (BTRFS_BLOCK_GROUP_TYPE_MASK &
1535                                                  em->map_lookup->type));
1536                                         ret = -EUCLEAN;
1537                                 } else {
1538                                         ret = 0;
1539                                 }
1540                         }
1541                         free_extent_map(em);
1542                         goto out;
1543                 }
1544                 path->slots[0]++;
1545         }
1546 out:
1547         return ret;
1548 }
1549
1550 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
1551 {
1552         u64 extra_flags = chunk_to_extended(flags) &
1553                                 BTRFS_EXTENDED_PROFILE_MASK;
1554
1555         write_seqlock(&fs_info->profiles_lock);
1556         if (flags & BTRFS_BLOCK_GROUP_DATA)
1557                 fs_info->avail_data_alloc_bits |= extra_flags;
1558         if (flags & BTRFS_BLOCK_GROUP_METADATA)
1559                 fs_info->avail_metadata_alloc_bits |= extra_flags;
1560         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
1561                 fs_info->avail_system_alloc_bits |= extra_flags;
1562         write_sequnlock(&fs_info->profiles_lock);
1563 }
1564
1565 /**
1566  * btrfs_rmap_block - Map a physical disk address to a list of logical addresses
1567  * @chunk_start:   logical address of block group
1568  * @physical:      physical address to map to logical addresses
1569  * @logical:       return array of logical addresses which map to @physical
1570  * @naddrs:        length of @logical
1571  * @stripe_len:    size of IO stripe for the given block group
1572  *
1573  * Maps a particular @physical disk address to a list of @logical addresses.
1574  * Used primarily to exclude those portions of a block group that contain super
1575  * block copies.
1576  */
1577 EXPORT_FOR_TESTS
1578 int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
1579                      u64 physical, u64 **logical, int *naddrs, int *stripe_len)
1580 {
1581         struct extent_map *em;
1582         struct map_lookup *map;
1583         u64 *buf;
1584         u64 bytenr;
1585         u64 data_stripe_length;
1586         u64 io_stripe_size;
1587         int i, nr = 0;
1588         int ret = 0;
1589
1590         em = btrfs_get_chunk_map(fs_info, chunk_start, 1);
1591         if (IS_ERR(em))
1592                 return -EIO;
1593
1594         map = em->map_lookup;
1595         data_stripe_length = em->len;
1596         io_stripe_size = map->stripe_len;
1597
1598         if (map->type & BTRFS_BLOCK_GROUP_RAID10)
1599                 data_stripe_length = div_u64(data_stripe_length,
1600                                              map->num_stripes / map->sub_stripes);
1601         else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
1602                 data_stripe_length = div_u64(data_stripe_length, map->num_stripes);
1603         else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
1604                 data_stripe_length = div_u64(data_stripe_length,
1605                                              nr_data_stripes(map));
1606                 io_stripe_size = map->stripe_len * nr_data_stripes(map);
1607         }
1608
1609         buf = kcalloc(map->num_stripes, sizeof(u64), GFP_NOFS);
1610         if (!buf) {
1611                 ret = -ENOMEM;
1612                 goto out;
1613         }
1614
1615         for (i = 0; i < map->num_stripes; i++) {
1616                 bool already_inserted = false;
1617                 u64 stripe_nr;
1618                 int j;
1619
1620                 if (!in_range(physical, map->stripes[i].physical,
1621                               data_stripe_length))
1622                         continue;
1623
1624                 stripe_nr = physical - map->stripes[i].physical;
1625                 stripe_nr = div64_u64(stripe_nr, map->stripe_len);
1626
1627                 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
1628                         stripe_nr = stripe_nr * map->num_stripes + i;
1629                         stripe_nr = div_u64(stripe_nr, map->sub_stripes);
1630                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
1631                         stripe_nr = stripe_nr * map->num_stripes + i;
1632                 }
1633                 /*
1634                  * The remaining case would be for RAID56, multiply by
1635                  * nr_data_stripes().  Alternatively, just use rmap_len below
1636                  * instead of map->stripe_len
1637                  */
1638
1639                 bytenr = chunk_start + stripe_nr * io_stripe_size;
1640
1641                 /* Ensure we don't add duplicate addresses */
1642                 for (j = 0; j < nr; j++) {
1643                         if (buf[j] == bytenr) {
1644                                 already_inserted = true;
1645                                 break;
1646                         }
1647                 }
1648
1649                 if (!already_inserted)
1650                         buf[nr++] = bytenr;
1651         }
1652
1653         *logical = buf;
1654         *naddrs = nr;
1655         *stripe_len = io_stripe_size;
1656 out:
1657         free_extent_map(em);
1658         return ret;
1659 }
1660
1661 static int exclude_super_stripes(struct btrfs_block_group *cache)
1662 {
1663         struct btrfs_fs_info *fs_info = cache->fs_info;
1664         u64 bytenr;
1665         u64 *logical;
1666         int stripe_len;
1667         int i, nr, ret;
1668
1669         if (cache->start < BTRFS_SUPER_INFO_OFFSET) {
1670                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->start;
1671                 cache->bytes_super += stripe_len;
1672                 ret = btrfs_add_excluded_extent(fs_info, cache->start,
1673                                                 stripe_len);
1674                 if (ret)
1675                         return ret;
1676         }
1677
1678         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
1679                 bytenr = btrfs_sb_offset(i);
1680                 ret = btrfs_rmap_block(fs_info, cache->start,
1681                                        bytenr, &logical, &nr, &stripe_len);
1682                 if (ret)
1683                         return ret;
1684
1685                 while (nr--) {
1686                         u64 start, len;
1687
1688                         if (logical[nr] > cache->start + cache->length)
1689                                 continue;
1690
1691                         if (logical[nr] + stripe_len <= cache->start)
1692                                 continue;
1693
1694                         start = logical[nr];
1695                         if (start < cache->start) {
1696                                 start = cache->start;
1697                                 len = (logical[nr] + stripe_len) - start;
1698                         } else {
1699                                 len = min_t(u64, stripe_len,
1700                                             cache->start + cache->length - start);
1701                         }
1702
1703                         cache->bytes_super += len;
1704                         ret = btrfs_add_excluded_extent(fs_info, start, len);
1705                         if (ret) {
1706                                 kfree(logical);
1707                                 return ret;
1708                         }
1709                 }
1710
1711                 kfree(logical);
1712         }
1713         return 0;
1714 }
1715
1716 static void link_block_group(struct btrfs_block_group *cache)
1717 {
1718         struct btrfs_space_info *space_info = cache->space_info;
1719         int index = btrfs_bg_flags_to_raid_index(cache->flags);
1720         bool first = false;
1721
1722         down_write(&space_info->groups_sem);
1723         if (list_empty(&space_info->block_groups[index]))
1724                 first = true;
1725         list_add_tail(&cache->list, &space_info->block_groups[index]);
1726         up_write(&space_info->groups_sem);
1727
1728         if (first)
1729                 btrfs_sysfs_add_block_group_type(cache);
1730 }
1731
1732 static struct btrfs_block_group *btrfs_create_block_group_cache(
1733                 struct btrfs_fs_info *fs_info, u64 start, u64 size)
1734 {
1735         struct btrfs_block_group *cache;
1736
1737         cache = kzalloc(sizeof(*cache), GFP_NOFS);
1738         if (!cache)
1739                 return NULL;
1740
1741         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
1742                                         GFP_NOFS);
1743         if (!cache->free_space_ctl) {
1744                 kfree(cache);
1745                 return NULL;
1746         }
1747
1748         cache->start = start;
1749         cache->length = size;
1750
1751         cache->fs_info = fs_info;
1752         cache->full_stripe_len = btrfs_full_stripe_len(fs_info, start);
1753         set_free_space_tree_thresholds(cache);
1754
1755         cache->discard_index = BTRFS_DISCARD_INDEX_UNUSED;
1756
1757         atomic_set(&cache->count, 1);
1758         spin_lock_init(&cache->lock);
1759         init_rwsem(&cache->data_rwsem);
1760         INIT_LIST_HEAD(&cache->list);
1761         INIT_LIST_HEAD(&cache->cluster_list);
1762         INIT_LIST_HEAD(&cache->bg_list);
1763         INIT_LIST_HEAD(&cache->ro_list);
1764         INIT_LIST_HEAD(&cache->discard_list);
1765         INIT_LIST_HEAD(&cache->dirty_list);
1766         INIT_LIST_HEAD(&cache->io_list);
1767         btrfs_init_free_space_ctl(cache);
1768         atomic_set(&cache->trimming, 0);
1769         mutex_init(&cache->free_space_lock);
1770         btrfs_init_full_stripe_locks_tree(&cache->full_stripe_locks_root);
1771
1772         return cache;
1773 }
1774
1775 /*
1776  * Iterate all chunks and verify that each of them has the corresponding block
1777  * group
1778  */
1779 static int check_chunk_block_group_mappings(struct btrfs_fs_info *fs_info)
1780 {
1781         struct extent_map_tree *map_tree = &fs_info->mapping_tree;
1782         struct extent_map *em;
1783         struct btrfs_block_group *bg;
1784         u64 start = 0;
1785         int ret = 0;
1786
1787         while (1) {
1788                 read_lock(&map_tree->lock);
1789                 /*
1790                  * lookup_extent_mapping will return the first extent map
1791                  * intersecting the range, so setting @len to 1 is enough to
1792                  * get the first chunk.
1793                  */
1794                 em = lookup_extent_mapping(map_tree, start, 1);
1795                 read_unlock(&map_tree->lock);
1796                 if (!em)
1797                         break;
1798
1799                 bg = btrfs_lookup_block_group(fs_info, em->start);
1800                 if (!bg) {
1801                         btrfs_err(fs_info,
1802         "chunk start=%llu len=%llu doesn't have corresponding block group",
1803                                      em->start, em->len);
1804                         ret = -EUCLEAN;
1805                         free_extent_map(em);
1806                         break;
1807                 }
1808                 if (bg->start != em->start || bg->length != em->len ||
1809                     (bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK) !=
1810                     (em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK)) {
1811                         btrfs_err(fs_info,
1812 "chunk start=%llu len=%llu flags=0x%llx doesn't match block group start=%llu len=%llu flags=0x%llx",
1813                                 em->start, em->len,
1814                                 em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK,
1815                                 bg->start, bg->length,
1816                                 bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK);
1817                         ret = -EUCLEAN;
1818                         free_extent_map(em);
1819                         btrfs_put_block_group(bg);
1820                         break;
1821                 }
1822                 start = em->start + em->len;
1823                 free_extent_map(em);
1824                 btrfs_put_block_group(bg);
1825         }
1826         return ret;
1827 }
1828
1829 static int read_one_block_group(struct btrfs_fs_info *info,
1830                                 struct btrfs_path *path,
1831                                 const struct btrfs_key *key,
1832                                 int need_clear)
1833 {
1834         struct extent_buffer *leaf = path->nodes[0];
1835         struct btrfs_block_group *cache;
1836         struct btrfs_space_info *space_info;
1837         struct btrfs_block_group_item bgi;
1838         const bool mixed = btrfs_fs_incompat(info, MIXED_GROUPS);
1839         int slot = path->slots[0];
1840         int ret;
1841
1842         ASSERT(key->type == BTRFS_BLOCK_GROUP_ITEM_KEY);
1843
1844         cache = btrfs_create_block_group_cache(info, key->objectid, key->offset);
1845         if (!cache)
1846                 return -ENOMEM;
1847
1848         if (need_clear) {
1849                 /*
1850                  * When we mount with old space cache, we need to
1851                  * set BTRFS_DC_CLEAR and set dirty flag.
1852                  *
1853                  * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
1854                  *    truncate the old free space cache inode and
1855                  *    setup a new one.
1856                  * b) Setting 'dirty flag' makes sure that we flush
1857                  *    the new space cache info onto disk.
1858                  */
1859                 if (btrfs_test_opt(info, SPACE_CACHE))
1860                         cache->disk_cache_state = BTRFS_DC_CLEAR;
1861         }
1862         read_extent_buffer(leaf, &bgi, btrfs_item_ptr_offset(leaf, slot),
1863                            sizeof(bgi));
1864         cache->used = btrfs_stack_block_group_used(&bgi);
1865         cache->flags = btrfs_stack_block_group_flags(&bgi);
1866         if (!mixed && ((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
1867             (cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
1868                         btrfs_err(info,
1869 "bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
1870                                   cache->start);
1871                         ret = -EINVAL;
1872                         goto error;
1873         }
1874
1875         /*
1876          * We need to exclude the super stripes now so that the space info has
1877          * super bytes accounted for, otherwise we'll think we have more space
1878          * than we actually do.
1879          */
1880         ret = exclude_super_stripes(cache);
1881         if (ret) {
1882                 /* We may have excluded something, so call this just in case. */
1883                 btrfs_free_excluded_extents(cache);
1884                 goto error;
1885         }
1886
1887         /*
1888          * Check for two cases, either we are full, and therefore don't need
1889          * to bother with the caching work since we won't find any space, or we
1890          * are empty, and we can just add all the space in and be done with it.
1891          * This saves us _a_lot_ of time, particularly in the full case.
1892          */
1893         if (key->offset == cache->used) {
1894                 cache->last_byte_to_unpin = (u64)-1;
1895                 cache->cached = BTRFS_CACHE_FINISHED;
1896                 btrfs_free_excluded_extents(cache);
1897         } else if (cache->used == 0) {
1898                 cache->last_byte_to_unpin = (u64)-1;
1899                 cache->cached = BTRFS_CACHE_FINISHED;
1900                 add_new_free_space(cache, key->objectid,
1901                                    key->objectid + key->offset);
1902                 btrfs_free_excluded_extents(cache);
1903         }
1904
1905         ret = btrfs_add_block_group_cache(info, cache);
1906         if (ret) {
1907                 btrfs_remove_free_space_cache(cache);
1908                 goto error;
1909         }
1910         trace_btrfs_add_block_group(info, cache, 0);
1911         btrfs_update_space_info(info, cache->flags, key->offset,
1912                                 cache->used, cache->bytes_super, &space_info);
1913
1914         cache->space_info = space_info;
1915
1916         link_block_group(cache);
1917
1918         set_avail_alloc_bits(info, cache->flags);
1919         if (btrfs_chunk_readonly(info, cache->start)) {
1920                 inc_block_group_ro(cache, 1);
1921         } else if (cache->used == 0) {
1922                 ASSERT(list_empty(&cache->bg_list));
1923                 if (btrfs_test_opt(info, DISCARD_ASYNC))
1924                         btrfs_discard_queue_work(&info->discard_ctl, cache);
1925                 else
1926                         btrfs_mark_bg_unused(cache);
1927         }
1928         return 0;
1929 error:
1930         btrfs_put_block_group(cache);
1931         return ret;
1932 }
1933
1934 int btrfs_read_block_groups(struct btrfs_fs_info *info)
1935 {
1936         struct btrfs_path *path;
1937         int ret;
1938         struct btrfs_block_group *cache;
1939         struct btrfs_space_info *space_info;
1940         struct btrfs_key key;
1941         int need_clear = 0;
1942         u64 cache_gen;
1943
1944         key.objectid = 0;
1945         key.offset = 0;
1946         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
1947         path = btrfs_alloc_path();
1948         if (!path)
1949                 return -ENOMEM;
1950         path->reada = READA_FORWARD;
1951
1952         cache_gen = btrfs_super_cache_generation(info->super_copy);
1953         if (btrfs_test_opt(info, SPACE_CACHE) &&
1954             btrfs_super_generation(info->super_copy) != cache_gen)
1955                 need_clear = 1;
1956         if (btrfs_test_opt(info, CLEAR_CACHE))
1957                 need_clear = 1;
1958
1959         while (1) {
1960                 ret = find_first_block_group(info, path, &key);
1961                 if (ret > 0)
1962                         break;
1963                 if (ret != 0)
1964                         goto error;
1965
1966                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1967                 ret = read_one_block_group(info, path, &key, need_clear);
1968                 if (ret < 0)
1969                         goto error;
1970                 key.objectid += key.offset;
1971                 key.offset = 0;
1972                 btrfs_release_path(path);
1973         }
1974
1975         list_for_each_entry_rcu(space_info, &info->space_info, list) {
1976                 if (!(btrfs_get_alloc_profile(info, space_info->flags) &
1977                       (BTRFS_BLOCK_GROUP_RAID10 |
1978                        BTRFS_BLOCK_GROUP_RAID1_MASK |
1979                        BTRFS_BLOCK_GROUP_RAID56_MASK |
1980                        BTRFS_BLOCK_GROUP_DUP)))
1981                         continue;
1982                 /*
1983                  * Avoid allocating from un-mirrored block group if there are
1984                  * mirrored block groups.
1985                  */
1986                 list_for_each_entry(cache,
1987                                 &space_info->block_groups[BTRFS_RAID_RAID0],
1988                                 list)
1989                         inc_block_group_ro(cache, 1);
1990                 list_for_each_entry(cache,
1991                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
1992                                 list)
1993                         inc_block_group_ro(cache, 1);
1994         }
1995
1996         btrfs_init_global_block_rsv(info);
1997         ret = check_chunk_block_group_mappings(info);
1998 error:
1999         btrfs_free_path(path);
2000         return ret;
2001 }
2002
2003 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans)
2004 {
2005         struct btrfs_fs_info *fs_info = trans->fs_info;
2006         struct btrfs_block_group *block_group;
2007         struct btrfs_root *extent_root = fs_info->extent_root;
2008         struct btrfs_block_group_item item;
2009         struct btrfs_key key;
2010         int ret = 0;
2011
2012         if (!trans->can_flush_pending_bgs)
2013                 return;
2014
2015         while (!list_empty(&trans->new_bgs)) {
2016                 block_group = list_first_entry(&trans->new_bgs,
2017                                                struct btrfs_block_group,
2018                                                bg_list);
2019                 if (ret)
2020                         goto next;
2021
2022                 spin_lock(&block_group->lock);
2023                 btrfs_set_stack_block_group_used(&item, block_group->used);
2024                 btrfs_set_stack_block_group_chunk_objectid(&item,
2025                                 BTRFS_FIRST_CHUNK_TREE_OBJECTID);
2026                 btrfs_set_stack_block_group_flags(&item, block_group->flags);
2027                 key.objectid = block_group->start;
2028                 key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
2029                 key.offset = block_group->length;
2030                 spin_unlock(&block_group->lock);
2031
2032                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
2033                                         sizeof(item));
2034                 if (ret)
2035                         btrfs_abort_transaction(trans, ret);
2036                 ret = btrfs_finish_chunk_alloc(trans, key.objectid, key.offset);
2037                 if (ret)
2038                         btrfs_abort_transaction(trans, ret);
2039                 add_block_group_free_space(trans, block_group);
2040                 /* Already aborted the transaction if it failed. */
2041 next:
2042                 btrfs_delayed_refs_rsv_release(fs_info, 1);
2043                 list_del_init(&block_group->bg_list);
2044         }
2045         btrfs_trans_release_chunk_metadata(trans);
2046 }
2047
2048 int btrfs_make_block_group(struct btrfs_trans_handle *trans, u64 bytes_used,
2049                            u64 type, u64 chunk_offset, u64 size)
2050 {
2051         struct btrfs_fs_info *fs_info = trans->fs_info;
2052         struct btrfs_block_group *cache;
2053         int ret;
2054
2055         btrfs_set_log_full_commit(trans);
2056
2057         cache = btrfs_create_block_group_cache(fs_info, chunk_offset, size);
2058         if (!cache)
2059                 return -ENOMEM;
2060
2061         cache->used = bytes_used;
2062         cache->flags = type;
2063         cache->last_byte_to_unpin = (u64)-1;
2064         cache->cached = BTRFS_CACHE_FINISHED;
2065         cache->needs_free_space = 1;
2066         ret = exclude_super_stripes(cache);
2067         if (ret) {
2068                 /* We may have excluded something, so call this just in case */
2069                 btrfs_free_excluded_extents(cache);
2070                 btrfs_put_block_group(cache);
2071                 return ret;
2072         }
2073
2074         add_new_free_space(cache, chunk_offset, chunk_offset + size);
2075
2076         btrfs_free_excluded_extents(cache);
2077
2078 #ifdef CONFIG_BTRFS_DEBUG
2079         if (btrfs_should_fragment_free_space(cache)) {
2080                 u64 new_bytes_used = size - bytes_used;
2081
2082                 bytes_used += new_bytes_used >> 1;
2083                 fragment_free_space(cache);
2084         }
2085 #endif
2086         /*
2087          * Ensure the corresponding space_info object is created and
2088          * assigned to our block group. We want our bg to be added to the rbtree
2089          * with its ->space_info set.
2090          */
2091         cache->space_info = btrfs_find_space_info(fs_info, cache->flags);
2092         ASSERT(cache->space_info);
2093
2094         ret = btrfs_add_block_group_cache(fs_info, cache);
2095         if (ret) {
2096                 btrfs_remove_free_space_cache(cache);
2097                 btrfs_put_block_group(cache);
2098                 return ret;
2099         }
2100
2101         /*
2102          * Now that our block group has its ->space_info set and is inserted in
2103          * the rbtree, update the space info's counters.
2104          */
2105         trace_btrfs_add_block_group(fs_info, cache, 1);
2106         btrfs_update_space_info(fs_info, cache->flags, size, bytes_used,
2107                                 cache->bytes_super, &cache->space_info);
2108         btrfs_update_global_block_rsv(fs_info);
2109
2110         link_block_group(cache);
2111
2112         list_add_tail(&cache->bg_list, &trans->new_bgs);
2113         trans->delayed_ref_updates++;
2114         btrfs_update_delayed_refs_rsv(trans);
2115
2116         set_avail_alloc_bits(fs_info, type);
2117         return 0;
2118 }
2119
2120 static u64 update_block_group_flags(struct btrfs_fs_info *fs_info, u64 flags)
2121 {
2122         u64 num_devices;
2123         u64 stripped;
2124
2125         /*
2126          * if restripe for this chunk_type is on pick target profile and
2127          * return, otherwise do the usual balance
2128          */
2129         stripped = get_restripe_target(fs_info, flags);
2130         if (stripped)
2131                 return extended_to_chunk(stripped);
2132
2133         num_devices = fs_info->fs_devices->rw_devices;
2134
2135         stripped = BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID56_MASK |
2136                 BTRFS_BLOCK_GROUP_RAID1_MASK | BTRFS_BLOCK_GROUP_RAID10;
2137
2138         if (num_devices == 1) {
2139                 stripped |= BTRFS_BLOCK_GROUP_DUP;
2140                 stripped = flags & ~stripped;
2141
2142                 /* turn raid0 into single device chunks */
2143                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
2144                         return stripped;
2145
2146                 /* turn mirroring into duplication */
2147                 if (flags & (BTRFS_BLOCK_GROUP_RAID1_MASK |
2148                              BTRFS_BLOCK_GROUP_RAID10))
2149                         return stripped | BTRFS_BLOCK_GROUP_DUP;
2150         } else {
2151                 /* they already had raid on here, just return */
2152                 if (flags & stripped)
2153                         return flags;
2154
2155                 stripped |= BTRFS_BLOCK_GROUP_DUP;
2156                 stripped = flags & ~stripped;
2157
2158                 /* switch duplicated blocks with raid1 */
2159                 if (flags & BTRFS_BLOCK_GROUP_DUP)
2160                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
2161
2162                 /* this is drive concat, leave it alone */
2163         }
2164
2165         return flags;
2166 }
2167
2168 /*
2169  * Mark one block group RO, can be called several times for the same block
2170  * group.
2171  *
2172  * @cache:              the destination block group
2173  * @do_chunk_alloc:     whether need to do chunk pre-allocation, this is to
2174  *                      ensure we still have some free space after marking this
2175  *                      block group RO.
2176  */
2177 int btrfs_inc_block_group_ro(struct btrfs_block_group *cache,
2178                              bool do_chunk_alloc)
2179 {
2180         struct btrfs_fs_info *fs_info = cache->fs_info;
2181         struct btrfs_trans_handle *trans;
2182         u64 alloc_flags;
2183         int ret;
2184
2185 again:
2186         trans = btrfs_join_transaction(fs_info->extent_root);
2187         if (IS_ERR(trans))
2188                 return PTR_ERR(trans);
2189
2190         /*
2191          * we're not allowed to set block groups readonly after the dirty
2192          * block groups cache has started writing.  If it already started,
2193          * back off and let this transaction commit
2194          */
2195         mutex_lock(&fs_info->ro_block_group_mutex);
2196         if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
2197                 u64 transid = trans->transid;
2198
2199                 mutex_unlock(&fs_info->ro_block_group_mutex);
2200                 btrfs_end_transaction(trans);
2201
2202                 ret = btrfs_wait_for_commit(fs_info, transid);
2203                 if (ret)
2204                         return ret;
2205                 goto again;
2206         }
2207
2208         if (do_chunk_alloc) {
2209                 /*
2210                  * If we are changing raid levels, try to allocate a
2211                  * corresponding block group with the new raid level.
2212                  */
2213                 alloc_flags = update_block_group_flags(fs_info, cache->flags);
2214                 if (alloc_flags != cache->flags) {
2215                         ret = btrfs_chunk_alloc(trans, alloc_flags,
2216                                                 CHUNK_ALLOC_FORCE);
2217                         /*
2218                          * ENOSPC is allowed here, we may have enough space
2219                          * already allocated at the new raid level to carry on
2220                          */
2221                         if (ret == -ENOSPC)
2222                                 ret = 0;
2223                         if (ret < 0)
2224                                 goto out;
2225                 }
2226         }
2227
2228         ret = inc_block_group_ro(cache, !do_chunk_alloc);
2229         if (!do_chunk_alloc)
2230                 goto unlock_out;
2231         if (!ret)
2232                 goto out;
2233         alloc_flags = btrfs_get_alloc_profile(fs_info, cache->space_info->flags);
2234         ret = btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
2235         if (ret < 0)
2236                 goto out;
2237         ret = inc_block_group_ro(cache, 0);
2238 out:
2239         if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
2240                 alloc_flags = update_block_group_flags(fs_info, cache->flags);
2241                 mutex_lock(&fs_info->chunk_mutex);
2242                 check_system_chunk(trans, alloc_flags);
2243                 mutex_unlock(&fs_info->chunk_mutex);
2244         }
2245 unlock_out:
2246         mutex_unlock(&fs_info->ro_block_group_mutex);
2247
2248         btrfs_end_transaction(trans);
2249         return ret;
2250 }
2251
2252 void btrfs_dec_block_group_ro(struct btrfs_block_group *cache)
2253 {
2254         struct btrfs_space_info *sinfo = cache->space_info;
2255         u64 num_bytes;
2256
2257         BUG_ON(!cache->ro);
2258
2259         spin_lock(&sinfo->lock);
2260         spin_lock(&cache->lock);
2261         if (!--cache->ro) {
2262                 num_bytes = cache->length - cache->reserved -
2263                             cache->pinned - cache->bytes_super - cache->used;
2264                 sinfo->bytes_readonly -= num_bytes;
2265                 list_del_init(&cache->ro_list);
2266         }
2267         spin_unlock(&cache->lock);
2268         spin_unlock(&sinfo->lock);
2269 }
2270
2271 static int write_one_cache_group(struct btrfs_trans_handle *trans,
2272                                  struct btrfs_path *path,
2273                                  struct btrfs_block_group *cache)
2274 {
2275         struct btrfs_fs_info *fs_info = trans->fs_info;
2276         int ret;
2277         struct btrfs_root *extent_root = fs_info->extent_root;
2278         unsigned long bi;
2279         struct extent_buffer *leaf;
2280         struct btrfs_block_group_item bgi;
2281         struct btrfs_key key;
2282
2283         key.objectid = cache->start;
2284         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
2285         key.offset = cache->length;
2286
2287         ret = btrfs_search_slot(trans, extent_root, &key, path, 0, 1);
2288         if (ret) {
2289                 if (ret > 0)
2290                         ret = -ENOENT;
2291                 goto fail;
2292         }
2293
2294         leaf = path->nodes[0];
2295         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
2296         btrfs_set_stack_block_group_used(&bgi, cache->used);
2297         btrfs_set_stack_block_group_chunk_objectid(&bgi,
2298                         BTRFS_FIRST_CHUNK_TREE_OBJECTID);
2299         btrfs_set_stack_block_group_flags(&bgi, cache->flags);
2300         write_extent_buffer(leaf, &bgi, bi, sizeof(bgi));
2301         btrfs_mark_buffer_dirty(leaf);
2302 fail:
2303         btrfs_release_path(path);
2304         return ret;
2305
2306 }
2307
2308 static int cache_save_setup(struct btrfs_block_group *block_group,
2309                             struct btrfs_trans_handle *trans,
2310                             struct btrfs_path *path)
2311 {
2312         struct btrfs_fs_info *fs_info = block_group->fs_info;
2313         struct btrfs_root *root = fs_info->tree_root;
2314         struct inode *inode = NULL;
2315         struct extent_changeset *data_reserved = NULL;
2316         u64 alloc_hint = 0;
2317         int dcs = BTRFS_DC_ERROR;
2318         u64 num_pages = 0;
2319         int retries = 0;
2320         int ret = 0;
2321
2322         /*
2323          * If this block group is smaller than 100 megs don't bother caching the
2324          * block group.
2325          */
2326         if (block_group->length < (100 * SZ_1M)) {
2327                 spin_lock(&block_group->lock);
2328                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
2329                 spin_unlock(&block_group->lock);
2330                 return 0;
2331         }
2332
2333         if (trans->aborted)
2334                 return 0;
2335 again:
2336         inode = lookup_free_space_inode(block_group, path);
2337         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
2338                 ret = PTR_ERR(inode);
2339                 btrfs_release_path(path);
2340                 goto out;
2341         }
2342
2343         if (IS_ERR(inode)) {
2344                 BUG_ON(retries);
2345                 retries++;
2346
2347                 if (block_group->ro)
2348                         goto out_free;
2349
2350                 ret = create_free_space_inode(trans, block_group, path);
2351                 if (ret)
2352                         goto out_free;
2353                 goto again;
2354         }
2355
2356         /*
2357          * We want to set the generation to 0, that way if anything goes wrong
2358          * from here on out we know not to trust this cache when we load up next
2359          * time.
2360          */
2361         BTRFS_I(inode)->generation = 0;
2362         ret = btrfs_update_inode(trans, root, inode);
2363         if (ret) {
2364                 /*
2365                  * So theoretically we could recover from this, simply set the
2366                  * super cache generation to 0 so we know to invalidate the
2367                  * cache, but then we'd have to keep track of the block groups
2368                  * that fail this way so we know we _have_ to reset this cache
2369                  * before the next commit or risk reading stale cache.  So to
2370                  * limit our exposure to horrible edge cases lets just abort the
2371                  * transaction, this only happens in really bad situations
2372                  * anyway.
2373                  */
2374                 btrfs_abort_transaction(trans, ret);
2375                 goto out_put;
2376         }
2377         WARN_ON(ret);
2378
2379         /* We've already setup this transaction, go ahead and exit */
2380         if (block_group->cache_generation == trans->transid &&
2381             i_size_read(inode)) {
2382                 dcs = BTRFS_DC_SETUP;
2383                 goto out_put;
2384         }
2385
2386         if (i_size_read(inode) > 0) {
2387                 ret = btrfs_check_trunc_cache_free_space(fs_info,
2388                                         &fs_info->global_block_rsv);
2389                 if (ret)
2390                         goto out_put;
2391
2392                 ret = btrfs_truncate_free_space_cache(trans, NULL, inode);
2393                 if (ret)
2394                         goto out_put;
2395         }
2396
2397         spin_lock(&block_group->lock);
2398         if (block_group->cached != BTRFS_CACHE_FINISHED ||
2399             !btrfs_test_opt(fs_info, SPACE_CACHE)) {
2400                 /*
2401                  * don't bother trying to write stuff out _if_
2402                  * a) we're not cached,
2403                  * b) we're with nospace_cache mount option,
2404                  * c) we're with v2 space_cache (FREE_SPACE_TREE).
2405                  */
2406                 dcs = BTRFS_DC_WRITTEN;
2407                 spin_unlock(&block_group->lock);
2408                 goto out_put;
2409         }
2410         spin_unlock(&block_group->lock);
2411
2412         /*
2413          * We hit an ENOSPC when setting up the cache in this transaction, just
2414          * skip doing the setup, we've already cleared the cache so we're safe.
2415          */
2416         if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
2417                 ret = -ENOSPC;
2418                 goto out_put;
2419         }
2420
2421         /*
2422          * Try to preallocate enough space based on how big the block group is.
2423          * Keep in mind this has to include any pinned space which could end up
2424          * taking up quite a bit since it's not folded into the other space
2425          * cache.
2426          */
2427         num_pages = div_u64(block_group->length, SZ_256M);
2428         if (!num_pages)
2429                 num_pages = 1;
2430
2431         num_pages *= 16;
2432         num_pages *= PAGE_SIZE;
2433
2434         ret = btrfs_check_data_free_space(inode, &data_reserved, 0, num_pages);
2435         if (ret)
2436                 goto out_put;
2437
2438         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
2439                                               num_pages, num_pages,
2440                                               &alloc_hint);
2441         /*
2442          * Our cache requires contiguous chunks so that we don't modify a bunch
2443          * of metadata or split extents when writing the cache out, which means
2444          * we can enospc if we are heavily fragmented in addition to just normal
2445          * out of space conditions.  So if we hit this just skip setting up any
2446          * other block groups for this transaction, maybe we'll unpin enough
2447          * space the next time around.
2448          */
2449         if (!ret)
2450                 dcs = BTRFS_DC_SETUP;
2451         else if (ret == -ENOSPC)
2452                 set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
2453
2454 out_put:
2455         iput(inode);
2456 out_free:
2457         btrfs_release_path(path);
2458 out:
2459         spin_lock(&block_group->lock);
2460         if (!ret && dcs == BTRFS_DC_SETUP)
2461                 block_group->cache_generation = trans->transid;
2462         block_group->disk_cache_state = dcs;
2463         spin_unlock(&block_group->lock);
2464
2465         extent_changeset_free(data_reserved);
2466         return ret;
2467 }
2468
2469 int btrfs_setup_space_cache(struct btrfs_trans_handle *trans)
2470 {
2471         struct btrfs_fs_info *fs_info = trans->fs_info;
2472         struct btrfs_block_group *cache, *tmp;
2473         struct btrfs_transaction *cur_trans = trans->transaction;
2474         struct btrfs_path *path;
2475
2476         if (list_empty(&cur_trans->dirty_bgs) ||
2477             !btrfs_test_opt(fs_info, SPACE_CACHE))
2478                 return 0;
2479
2480         path = btrfs_alloc_path();
2481         if (!path)
2482                 return -ENOMEM;
2483
2484         /* Could add new block groups, use _safe just in case */
2485         list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
2486                                  dirty_list) {
2487                 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
2488                         cache_save_setup(cache, trans, path);
2489         }
2490
2491         btrfs_free_path(path);
2492         return 0;
2493 }
2494
2495 /*
2496  * Transaction commit does final block group cache writeback during a critical
2497  * section where nothing is allowed to change the FS.  This is required in
2498  * order for the cache to actually match the block group, but can introduce a
2499  * lot of latency into the commit.
2500  *
2501  * So, btrfs_start_dirty_block_groups is here to kick off block group cache IO.
2502  * There's a chance we'll have to redo some of it if the block group changes
2503  * again during the commit, but it greatly reduces the commit latency by
2504  * getting rid of the easy block groups while we're still allowing others to
2505  * join the commit.
2506  */
2507 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans)
2508 {
2509         struct btrfs_fs_info *fs_info = trans->fs_info;
2510         struct btrfs_block_group *cache;
2511         struct btrfs_transaction *cur_trans = trans->transaction;
2512         int ret = 0;
2513         int should_put;
2514         struct btrfs_path *path = NULL;
2515         LIST_HEAD(dirty);
2516         struct list_head *io = &cur_trans->io_bgs;
2517         int num_started = 0;
2518         int loops = 0;
2519
2520         spin_lock(&cur_trans->dirty_bgs_lock);
2521         if (list_empty(&cur_trans->dirty_bgs)) {
2522                 spin_unlock(&cur_trans->dirty_bgs_lock);
2523                 return 0;
2524         }
2525         list_splice_init(&cur_trans->dirty_bgs, &dirty);
2526         spin_unlock(&cur_trans->dirty_bgs_lock);
2527
2528 again:
2529         /* Make sure all the block groups on our dirty list actually exist */
2530         btrfs_create_pending_block_groups(trans);
2531
2532         if (!path) {
2533                 path = btrfs_alloc_path();
2534                 if (!path)
2535                         return -ENOMEM;
2536         }
2537
2538         /*
2539          * cache_write_mutex is here only to save us from balance or automatic
2540          * removal of empty block groups deleting this block group while we are
2541          * writing out the cache
2542          */
2543         mutex_lock(&trans->transaction->cache_write_mutex);
2544         while (!list_empty(&dirty)) {
2545                 bool drop_reserve = true;
2546
2547                 cache = list_first_entry(&dirty, struct btrfs_block_group,
2548                                          dirty_list);
2549                 /*
2550                  * This can happen if something re-dirties a block group that
2551                  * is already under IO.  Just wait for it to finish and then do
2552                  * it all again
2553                  */
2554                 if (!list_empty(&cache->io_list)) {
2555                         list_del_init(&cache->io_list);
2556                         btrfs_wait_cache_io(trans, cache, path);
2557                         btrfs_put_block_group(cache);
2558                 }
2559
2560
2561                 /*
2562                  * btrfs_wait_cache_io uses the cache->dirty_list to decide if
2563                  * it should update the cache_state.  Don't delete until after
2564                  * we wait.
2565                  *
2566                  * Since we're not running in the commit critical section
2567                  * we need the dirty_bgs_lock to protect from update_block_group
2568                  */
2569                 spin_lock(&cur_trans->dirty_bgs_lock);
2570                 list_del_init(&cache->dirty_list);
2571                 spin_unlock(&cur_trans->dirty_bgs_lock);
2572
2573                 should_put = 1;
2574
2575                 cache_save_setup(cache, trans, path);
2576
2577                 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
2578                         cache->io_ctl.inode = NULL;
2579                         ret = btrfs_write_out_cache(trans, cache, path);
2580                         if (ret == 0 && cache->io_ctl.inode) {
2581                                 num_started++;
2582                                 should_put = 0;
2583
2584                                 /*
2585                                  * The cache_write_mutex is protecting the
2586                                  * io_list, also refer to the definition of
2587                                  * btrfs_transaction::io_bgs for more details
2588                                  */
2589                                 list_add_tail(&cache->io_list, io);
2590                         } else {
2591                                 /*
2592                                  * If we failed to write the cache, the
2593                                  * generation will be bad and life goes on
2594                                  */
2595                                 ret = 0;
2596                         }
2597                 }
2598                 if (!ret) {
2599                         ret = write_one_cache_group(trans, path, cache);
2600                         /*
2601                          * Our block group might still be attached to the list
2602                          * of new block groups in the transaction handle of some
2603                          * other task (struct btrfs_trans_handle->new_bgs). This
2604                          * means its block group item isn't yet in the extent
2605                          * tree. If this happens ignore the error, as we will
2606                          * try again later in the critical section of the
2607                          * transaction commit.
2608                          */
2609                         if (ret == -ENOENT) {
2610                                 ret = 0;
2611                                 spin_lock(&cur_trans->dirty_bgs_lock);
2612                                 if (list_empty(&cache->dirty_list)) {
2613                                         list_add_tail(&cache->dirty_list,
2614                                                       &cur_trans->dirty_bgs);
2615                                         btrfs_get_block_group(cache);
2616                                         drop_reserve = false;
2617                                 }
2618                                 spin_unlock(&cur_trans->dirty_bgs_lock);
2619                         } else if (ret) {
2620                                 btrfs_abort_transaction(trans, ret);
2621                         }
2622                 }
2623
2624                 /* If it's not on the io list, we need to put the block group */
2625                 if (should_put)
2626                         btrfs_put_block_group(cache);
2627                 if (drop_reserve)
2628                         btrfs_delayed_refs_rsv_release(fs_info, 1);
2629
2630                 if (ret)
2631                         break;
2632
2633                 /*
2634                  * Avoid blocking other tasks for too long. It might even save
2635                  * us from writing caches for block groups that are going to be
2636                  * removed.
2637                  */
2638                 mutex_unlock(&trans->transaction->cache_write_mutex);
2639                 mutex_lock(&trans->transaction->cache_write_mutex);
2640         }
2641         mutex_unlock(&trans->transaction->cache_write_mutex);
2642
2643         /*
2644          * Go through delayed refs for all the stuff we've just kicked off
2645          * and then loop back (just once)
2646          */
2647         ret = btrfs_run_delayed_refs(trans, 0);
2648         if (!ret && loops == 0) {
2649                 loops++;
2650                 spin_lock(&cur_trans->dirty_bgs_lock);
2651                 list_splice_init(&cur_trans->dirty_bgs, &dirty);
2652                 /*
2653                  * dirty_bgs_lock protects us from concurrent block group
2654                  * deletes too (not just cache_write_mutex).
2655                  */
2656                 if (!list_empty(&dirty)) {
2657                         spin_unlock(&cur_trans->dirty_bgs_lock);
2658                         goto again;
2659                 }
2660                 spin_unlock(&cur_trans->dirty_bgs_lock);
2661         } else if (ret < 0) {
2662                 btrfs_cleanup_dirty_bgs(cur_trans, fs_info);
2663         }
2664
2665         btrfs_free_path(path);
2666         return ret;
2667 }
2668
2669 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans)
2670 {
2671         struct btrfs_fs_info *fs_info = trans->fs_info;
2672         struct btrfs_block_group *cache;
2673         struct btrfs_transaction *cur_trans = trans->transaction;
2674         int ret = 0;
2675         int should_put;
2676         struct btrfs_path *path;
2677         struct list_head *io = &cur_trans->io_bgs;
2678         int num_started = 0;
2679
2680         path = btrfs_alloc_path();
2681         if (!path)
2682                 return -ENOMEM;
2683
2684         /*
2685          * Even though we are in the critical section of the transaction commit,
2686          * we can still have concurrent tasks adding elements to this
2687          * transaction's list of dirty block groups. These tasks correspond to
2688          * endio free space workers started when writeback finishes for a
2689          * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
2690          * allocate new block groups as a result of COWing nodes of the root
2691          * tree when updating the free space inode. The writeback for the space
2692          * caches is triggered by an earlier call to
2693          * btrfs_start_dirty_block_groups() and iterations of the following
2694          * loop.
2695          * Also we want to do the cache_save_setup first and then run the
2696          * delayed refs to make sure we have the best chance at doing this all
2697          * in one shot.
2698          */
2699         spin_lock(&cur_trans->dirty_bgs_lock);
2700         while (!list_empty(&cur_trans->dirty_bgs)) {
2701                 cache = list_first_entry(&cur_trans->dirty_bgs,
2702                                          struct btrfs_block_group,
2703                                          dirty_list);
2704
2705                 /*
2706                  * This can happen if cache_save_setup re-dirties a block group
2707                  * that is already under IO.  Just wait for it to finish and
2708                  * then do it all again
2709                  */
2710                 if (!list_empty(&cache->io_list)) {
2711                         spin_unlock(&cur_trans->dirty_bgs_lock);
2712                         list_del_init(&cache->io_list);
2713                         btrfs_wait_cache_io(trans, cache, path);
2714                         btrfs_put_block_group(cache);
2715                         spin_lock(&cur_trans->dirty_bgs_lock);
2716                 }
2717
2718                 /*
2719                  * Don't remove from the dirty list until after we've waited on
2720                  * any pending IO
2721                  */
2722                 list_del_init(&cache->dirty_list);
2723                 spin_unlock(&cur_trans->dirty_bgs_lock);
2724                 should_put = 1;
2725
2726                 cache_save_setup(cache, trans, path);
2727
2728                 if (!ret)
2729                         ret = btrfs_run_delayed_refs(trans,
2730                                                      (unsigned long) -1);
2731
2732                 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
2733                         cache->io_ctl.inode = NULL;
2734                         ret = btrfs_write_out_cache(trans, cache, path);
2735                         if (ret == 0 && cache->io_ctl.inode) {
2736                                 num_started++;
2737                                 should_put = 0;
2738                                 list_add_tail(&cache->io_list, io);
2739                         } else {
2740                                 /*
2741                                  * If we failed to write the cache, the
2742                                  * generation will be bad and life goes on
2743                                  */
2744                                 ret = 0;
2745                         }
2746                 }
2747                 if (!ret) {
2748                         ret = write_one_cache_group(trans, path, cache);
2749                         /*
2750                          * One of the free space endio workers might have
2751                          * created a new block group while updating a free space
2752                          * cache's inode (at inode.c:btrfs_finish_ordered_io())
2753                          * and hasn't released its transaction handle yet, in
2754                          * which case the new block group is still attached to
2755                          * its transaction handle and its creation has not
2756                          * finished yet (no block group item in the extent tree
2757                          * yet, etc). If this is the case, wait for all free
2758                          * space endio workers to finish and retry. This is a
2759                          * a very rare case so no need for a more efficient and
2760                          * complex approach.
2761                          */
2762                         if (ret == -ENOENT) {
2763                                 wait_event(cur_trans->writer_wait,
2764                                    atomic_read(&cur_trans->num_writers) == 1);
2765                                 ret = write_one_cache_group(trans, path, cache);
2766                         }
2767                         if (ret)
2768                                 btrfs_abort_transaction(trans, ret);
2769                 }
2770
2771                 /* If its not on the io list, we need to put the block group */
2772                 if (should_put)
2773                         btrfs_put_block_group(cache);
2774                 btrfs_delayed_refs_rsv_release(fs_info, 1);
2775                 spin_lock(&cur_trans->dirty_bgs_lock);
2776         }
2777         spin_unlock(&cur_trans->dirty_bgs_lock);
2778
2779         /*
2780          * Refer to the definition of io_bgs member for details why it's safe
2781          * to use it without any locking
2782          */
2783         while (!list_empty(io)) {
2784                 cache = list_first_entry(io, struct btrfs_block_group,
2785                                          io_list);
2786                 list_del_init(&cache->io_list);
2787                 btrfs_wait_cache_io(trans, cache, path);
2788                 btrfs_put_block_group(cache);
2789         }
2790
2791         btrfs_free_path(path);
2792         return ret;
2793 }
2794
2795 int btrfs_update_block_group(struct btrfs_trans_handle *trans,
2796                              u64 bytenr, u64 num_bytes, int alloc)
2797 {
2798         struct btrfs_fs_info *info = trans->fs_info;
2799         struct btrfs_block_group *cache = NULL;
2800         u64 total = num_bytes;
2801         u64 old_val;
2802         u64 byte_in_group;
2803         int factor;
2804         int ret = 0;
2805
2806         /* Block accounting for super block */
2807         spin_lock(&info->delalloc_root_lock);
2808         old_val = btrfs_super_bytes_used(info->super_copy);
2809         if (alloc)
2810                 old_val += num_bytes;
2811         else
2812                 old_val -= num_bytes;
2813         btrfs_set_super_bytes_used(info->super_copy, old_val);
2814         spin_unlock(&info->delalloc_root_lock);
2815
2816         while (total) {
2817                 cache = btrfs_lookup_block_group(info, bytenr);
2818                 if (!cache) {
2819                         ret = -ENOENT;
2820                         break;
2821                 }
2822                 factor = btrfs_bg_type_to_factor(cache->flags);
2823
2824                 /*
2825                  * If this block group has free space cache written out, we
2826                  * need to make sure to load it if we are removing space.  This
2827                  * is because we need the unpinning stage to actually add the
2828                  * space back to the block group, otherwise we will leak space.
2829                  */
2830                 if (!alloc && !btrfs_block_group_done(cache))
2831                         btrfs_cache_block_group(cache, 1);
2832
2833                 byte_in_group = bytenr - cache->start;
2834                 WARN_ON(byte_in_group > cache->length);
2835
2836                 spin_lock(&cache->space_info->lock);
2837                 spin_lock(&cache->lock);
2838
2839                 if (btrfs_test_opt(info, SPACE_CACHE) &&
2840                     cache->disk_cache_state < BTRFS_DC_CLEAR)
2841                         cache->disk_cache_state = BTRFS_DC_CLEAR;
2842
2843                 old_val = cache->used;
2844                 num_bytes = min(total, cache->length - byte_in_group);
2845                 if (alloc) {
2846                         old_val += num_bytes;
2847                         cache->used = old_val;
2848                         cache->reserved -= num_bytes;
2849                         cache->space_info->bytes_reserved -= num_bytes;
2850                         cache->space_info->bytes_used += num_bytes;
2851                         cache->space_info->disk_used += num_bytes * factor;
2852                         spin_unlock(&cache->lock);
2853                         spin_unlock(&cache->space_info->lock);
2854                 } else {
2855                         old_val -= num_bytes;
2856                         cache->used = old_val;
2857                         cache->pinned += num_bytes;
2858                         btrfs_space_info_update_bytes_pinned(info,
2859                                         cache->space_info, num_bytes);
2860                         cache->space_info->bytes_used -= num_bytes;
2861                         cache->space_info->disk_used -= num_bytes * factor;
2862                         spin_unlock(&cache->lock);
2863                         spin_unlock(&cache->space_info->lock);
2864
2865                         percpu_counter_add_batch(
2866                                         &cache->space_info->total_bytes_pinned,
2867                                         num_bytes,
2868                                         BTRFS_TOTAL_BYTES_PINNED_BATCH);
2869                         set_extent_dirty(info->pinned_extents,
2870                                          bytenr, bytenr + num_bytes - 1,
2871                                          GFP_NOFS | __GFP_NOFAIL);
2872                 }
2873
2874                 spin_lock(&trans->transaction->dirty_bgs_lock);
2875                 if (list_empty(&cache->dirty_list)) {
2876                         list_add_tail(&cache->dirty_list,
2877                                       &trans->transaction->dirty_bgs);
2878                         trans->delayed_ref_updates++;
2879                         btrfs_get_block_group(cache);
2880                 }
2881                 spin_unlock(&trans->transaction->dirty_bgs_lock);
2882
2883                 /*
2884                  * No longer have used bytes in this block group, queue it for
2885                  * deletion. We do this after adding the block group to the
2886                  * dirty list to avoid races between cleaner kthread and space
2887                  * cache writeout.
2888                  */
2889                 if (!alloc && old_val == 0) {
2890                         if (!btrfs_test_opt(info, DISCARD_ASYNC))
2891                                 btrfs_mark_bg_unused(cache);
2892                 }
2893
2894                 btrfs_put_block_group(cache);
2895                 total -= num_bytes;
2896                 bytenr += num_bytes;
2897         }
2898
2899         /* Modified block groups are accounted for in the delayed_refs_rsv. */
2900         btrfs_update_delayed_refs_rsv(trans);
2901         return ret;
2902 }
2903
2904 /**
2905  * btrfs_add_reserved_bytes - update the block_group and space info counters
2906  * @cache:      The cache we are manipulating
2907  * @ram_bytes:  The number of bytes of file content, and will be same to
2908  *              @num_bytes except for the compress path.
2909  * @num_bytes:  The number of bytes in question
2910  * @delalloc:   The blocks are allocated for the delalloc write
2911  *
2912  * This is called by the allocator when it reserves space. If this is a
2913  * reservation and the block group has become read only we cannot make the
2914  * reservation and return -EAGAIN, otherwise this function always succeeds.
2915  */
2916 int btrfs_add_reserved_bytes(struct btrfs_block_group *cache,
2917                              u64 ram_bytes, u64 num_bytes, int delalloc)
2918 {
2919         struct btrfs_space_info *space_info = cache->space_info;
2920         int ret = 0;
2921
2922         spin_lock(&space_info->lock);
2923         spin_lock(&cache->lock);
2924         if (cache->ro) {
2925                 ret = -EAGAIN;
2926         } else {
2927                 cache->reserved += num_bytes;
2928                 space_info->bytes_reserved += num_bytes;
2929                 trace_btrfs_space_reservation(cache->fs_info, "space_info",
2930                                               space_info->flags, num_bytes, 1);
2931                 btrfs_space_info_update_bytes_may_use(cache->fs_info,
2932                                                       space_info, -ram_bytes);
2933                 if (delalloc)
2934                         cache->delalloc_bytes += num_bytes;
2935         }
2936         spin_unlock(&cache->lock);
2937         spin_unlock(&space_info->lock);
2938         return ret;
2939 }
2940
2941 /**
2942  * btrfs_free_reserved_bytes - update the block_group and space info counters
2943  * @cache:      The cache we are manipulating
2944  * @num_bytes:  The number of bytes in question
2945  * @delalloc:   The blocks are allocated for the delalloc write
2946  *
2947  * This is called by somebody who is freeing space that was never actually used
2948  * on disk.  For example if you reserve some space for a new leaf in transaction
2949  * A and before transaction A commits you free that leaf, you call this with
2950  * reserve set to 0 in order to clear the reservation.
2951  */
2952 void btrfs_free_reserved_bytes(struct btrfs_block_group *cache,
2953                                u64 num_bytes, int delalloc)
2954 {
2955         struct btrfs_space_info *space_info = cache->space_info;
2956
2957         spin_lock(&space_info->lock);
2958         spin_lock(&cache->lock);
2959         if (cache->ro)
2960                 space_info->bytes_readonly += num_bytes;
2961         cache->reserved -= num_bytes;
2962         space_info->bytes_reserved -= num_bytes;
2963         space_info->max_extent_size = 0;
2964
2965         if (delalloc)
2966                 cache->delalloc_bytes -= num_bytes;
2967         spin_unlock(&cache->lock);
2968         spin_unlock(&space_info->lock);
2969 }
2970
2971 static void force_metadata_allocation(struct btrfs_fs_info *info)
2972 {
2973         struct list_head *head = &info->space_info;
2974         struct btrfs_space_info *found;
2975
2976         rcu_read_lock();
2977         list_for_each_entry_rcu(found, head, list) {
2978                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
2979                         found->force_alloc = CHUNK_ALLOC_FORCE;
2980         }
2981         rcu_read_unlock();
2982 }
2983
2984 static int should_alloc_chunk(struct btrfs_fs_info *fs_info,
2985                               struct btrfs_space_info *sinfo, int force)
2986 {
2987         u64 bytes_used = btrfs_space_info_used(sinfo, false);
2988         u64 thresh;
2989
2990         if (force == CHUNK_ALLOC_FORCE)
2991                 return 1;
2992
2993         /*
2994          * in limited mode, we want to have some free space up to
2995          * about 1% of the FS size.
2996          */
2997         if (force == CHUNK_ALLOC_LIMITED) {
2998                 thresh = btrfs_super_total_bytes(fs_info->super_copy);
2999                 thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
3000
3001                 if (sinfo->total_bytes - bytes_used < thresh)
3002                         return 1;
3003         }
3004
3005         if (bytes_used + SZ_2M < div_factor(sinfo->total_bytes, 8))
3006                 return 0;
3007         return 1;
3008 }
3009
3010 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans, u64 type)
3011 {
3012         u64 alloc_flags = btrfs_get_alloc_profile(trans->fs_info, type);
3013
3014         return btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
3015 }
3016
3017 /*
3018  * If force is CHUNK_ALLOC_FORCE:
3019  *    - return 1 if it successfully allocates a chunk,
3020  *    - return errors including -ENOSPC otherwise.
3021  * If force is NOT CHUNK_ALLOC_FORCE:
3022  *    - return 0 if it doesn't need to allocate a new chunk,
3023  *    - return 1 if it successfully allocates a chunk,
3024  *    - return errors including -ENOSPC otherwise.
3025  */
3026 int btrfs_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags,
3027                       enum btrfs_chunk_alloc_enum force)
3028 {
3029         struct btrfs_fs_info *fs_info = trans->fs_info;
3030         struct btrfs_space_info *space_info;
3031         bool wait_for_alloc = false;
3032         bool should_alloc = false;
3033         int ret = 0;
3034
3035         /* Don't re-enter if we're already allocating a chunk */
3036         if (trans->allocating_chunk)
3037                 return -ENOSPC;
3038
3039         space_info = btrfs_find_space_info(fs_info, flags);
3040         ASSERT(space_info);
3041
3042         do {
3043                 spin_lock(&space_info->lock);
3044                 if (force < space_info->force_alloc)
3045                         force = space_info->force_alloc;
3046                 should_alloc = should_alloc_chunk(fs_info, space_info, force);
3047                 if (space_info->full) {
3048                         /* No more free physical space */
3049                         if (should_alloc)
3050                                 ret = -ENOSPC;
3051                         else
3052                                 ret = 0;
3053                         spin_unlock(&space_info->lock);
3054                         return ret;
3055                 } else if (!should_alloc) {
3056                         spin_unlock(&space_info->lock);
3057                         return 0;
3058                 } else if (space_info->chunk_alloc) {
3059                         /*
3060                          * Someone is already allocating, so we need to block
3061                          * until this someone is finished and then loop to
3062                          * recheck if we should continue with our allocation
3063                          * attempt.
3064                          */
3065                         wait_for_alloc = true;
3066                         spin_unlock(&space_info->lock);
3067                         mutex_lock(&fs_info->chunk_mutex);
3068                         mutex_unlock(&fs_info->chunk_mutex);
3069                 } else {
3070                         /* Proceed with allocation */
3071                         space_info->chunk_alloc = 1;
3072                         wait_for_alloc = false;
3073                         spin_unlock(&space_info->lock);
3074                 }
3075
3076                 cond_resched();
3077         } while (wait_for_alloc);
3078
3079         mutex_lock(&fs_info->chunk_mutex);
3080         trans->allocating_chunk = true;
3081
3082         /*
3083          * If we have mixed data/metadata chunks we want to make sure we keep
3084          * allocating mixed chunks instead of individual chunks.
3085          */
3086         if (btrfs_mixed_space_info(space_info))
3087                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3088
3089         /*
3090          * if we're doing a data chunk, go ahead and make sure that
3091          * we keep a reasonable number of metadata chunks allocated in the
3092          * FS as well.
3093          */
3094         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3095                 fs_info->data_chunk_allocations++;
3096                 if (!(fs_info->data_chunk_allocations %
3097                       fs_info->metadata_ratio))
3098                         force_metadata_allocation(fs_info);
3099         }
3100
3101         /*
3102          * Check if we have enough space in SYSTEM chunk because we may need
3103          * to update devices.
3104          */
3105         check_system_chunk(trans, flags);
3106
3107         ret = btrfs_alloc_chunk(trans, flags);
3108         trans->allocating_chunk = false;
3109
3110         spin_lock(&space_info->lock);
3111         if (ret < 0) {
3112                 if (ret == -ENOSPC)
3113                         space_info->full = 1;
3114                 else
3115                         goto out;
3116         } else {
3117                 ret = 1;
3118                 space_info->max_extent_size = 0;
3119         }
3120
3121         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3122 out:
3123         space_info->chunk_alloc = 0;
3124         spin_unlock(&space_info->lock);
3125         mutex_unlock(&fs_info->chunk_mutex);
3126         /*
3127          * When we allocate a new chunk we reserve space in the chunk block
3128          * reserve to make sure we can COW nodes/leafs in the chunk tree or
3129          * add new nodes/leafs to it if we end up needing to do it when
3130          * inserting the chunk item and updating device items as part of the
3131          * second phase of chunk allocation, performed by
3132          * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
3133          * large number of new block groups to create in our transaction
3134          * handle's new_bgs list to avoid exhausting the chunk block reserve
3135          * in extreme cases - like having a single transaction create many new
3136          * block groups when starting to write out the free space caches of all
3137          * the block groups that were made dirty during the lifetime of the
3138          * transaction.
3139          */
3140         if (trans->chunk_bytes_reserved >= (u64)SZ_2M)
3141                 btrfs_create_pending_block_groups(trans);
3142
3143         return ret;
3144 }
3145
3146 static u64 get_profile_num_devs(struct btrfs_fs_info *fs_info, u64 type)
3147 {
3148         u64 num_dev;
3149
3150         num_dev = btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)].devs_max;
3151         if (!num_dev)
3152                 num_dev = fs_info->fs_devices->rw_devices;
3153
3154         return num_dev;
3155 }
3156
3157 /*
3158  * Reserve space in the system space for allocating or removing a chunk
3159  */
3160 void check_system_chunk(struct btrfs_trans_handle *trans, u64 type)
3161 {
3162         struct btrfs_fs_info *fs_info = trans->fs_info;
3163         struct btrfs_space_info *info;
3164         u64 left;
3165         u64 thresh;
3166         int ret = 0;
3167         u64 num_devs;
3168
3169         /*
3170          * Needed because we can end up allocating a system chunk and for an
3171          * atomic and race free space reservation in the chunk block reserve.
3172          */
3173         lockdep_assert_held(&fs_info->chunk_mutex);
3174
3175         info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
3176         spin_lock(&info->lock);
3177         left = info->total_bytes - btrfs_space_info_used(info, true);
3178         spin_unlock(&info->lock);
3179
3180         num_devs = get_profile_num_devs(fs_info, type);
3181
3182         /* num_devs device items to update and 1 chunk item to add or remove */
3183         thresh = btrfs_calc_metadata_size(fs_info, num_devs) +
3184                 btrfs_calc_insert_metadata_size(fs_info, 1);
3185
3186         if (left < thresh && btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
3187                 btrfs_info(fs_info, "left=%llu, need=%llu, flags=%llu",
3188                            left, thresh, type);
3189                 btrfs_dump_space_info(fs_info, info, 0, 0);
3190         }
3191
3192         if (left < thresh) {
3193                 u64 flags = btrfs_system_alloc_profile(fs_info);
3194
3195                 /*
3196                  * Ignore failure to create system chunk. We might end up not
3197                  * needing it, as we might not need to COW all nodes/leafs from
3198                  * the paths we visit in the chunk tree (they were already COWed
3199                  * or created in the current transaction for example).
3200                  */
3201                 ret = btrfs_alloc_chunk(trans, flags);
3202         }
3203
3204         if (!ret) {
3205                 ret = btrfs_block_rsv_add(fs_info->chunk_root,
3206                                           &fs_info->chunk_block_rsv,
3207                                           thresh, BTRFS_RESERVE_NO_FLUSH);
3208                 if (!ret)
3209                         trans->chunk_bytes_reserved += thresh;
3210         }
3211 }
3212
3213 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
3214 {
3215         struct btrfs_block_group *block_group;
3216         u64 last = 0;
3217
3218         while (1) {
3219                 struct inode *inode;
3220
3221                 block_group = btrfs_lookup_first_block_group(info, last);
3222                 while (block_group) {
3223                         btrfs_wait_block_group_cache_done(block_group);
3224                         spin_lock(&block_group->lock);
3225                         if (block_group->iref)
3226                                 break;
3227                         spin_unlock(&block_group->lock);
3228                         block_group = btrfs_next_block_group(block_group);
3229                 }
3230                 if (!block_group) {
3231                         if (last == 0)
3232                                 break;
3233                         last = 0;
3234                         continue;
3235                 }
3236
3237                 inode = block_group->inode;
3238                 block_group->iref = 0;
3239                 block_group->inode = NULL;
3240                 spin_unlock(&block_group->lock);
3241                 ASSERT(block_group->io_ctl.inode == NULL);
3242                 iput(inode);
3243                 last = block_group->start + block_group->length;
3244                 btrfs_put_block_group(block_group);
3245         }
3246 }
3247
3248 /*
3249  * Must be called only after stopping all workers, since we could have block
3250  * group caching kthreads running, and therefore they could race with us if we
3251  * freed the block groups before stopping them.
3252  */
3253 int btrfs_free_block_groups(struct btrfs_fs_info *info)
3254 {
3255         struct btrfs_block_group *block_group;
3256         struct btrfs_space_info *space_info;
3257         struct btrfs_caching_control *caching_ctl;
3258         struct rb_node *n;
3259
3260         down_write(&info->commit_root_sem);
3261         while (!list_empty(&info->caching_block_groups)) {
3262                 caching_ctl = list_entry(info->caching_block_groups.next,
3263                                          struct btrfs_caching_control, list);
3264                 list_del(&caching_ctl->list);
3265                 btrfs_put_caching_control(caching_ctl);
3266         }
3267         up_write(&info->commit_root_sem);
3268
3269         spin_lock(&info->unused_bgs_lock);
3270         while (!list_empty(&info->unused_bgs)) {
3271                 block_group = list_first_entry(&info->unused_bgs,
3272                                                struct btrfs_block_group,
3273                                                bg_list);
3274                 list_del_init(&block_group->bg_list);
3275                 btrfs_put_block_group(block_group);
3276         }
3277         spin_unlock(&info->unused_bgs_lock);
3278
3279         spin_lock(&info->block_group_cache_lock);
3280         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
3281                 block_group = rb_entry(n, struct btrfs_block_group,
3282                                        cache_node);
3283                 rb_erase(&block_group->cache_node,
3284                          &info->block_group_cache_tree);
3285                 RB_CLEAR_NODE(&block_group->cache_node);
3286                 spin_unlock(&info->block_group_cache_lock);
3287
3288                 down_write(&block_group->space_info->groups_sem);
3289                 list_del(&block_group->list);
3290                 up_write(&block_group->space_info->groups_sem);
3291
3292                 /*
3293                  * We haven't cached this block group, which means we could
3294                  * possibly have excluded extents on this block group.
3295                  */
3296                 if (block_group->cached == BTRFS_CACHE_NO ||
3297                     block_group->cached == BTRFS_CACHE_ERROR)
3298                         btrfs_free_excluded_extents(block_group);
3299
3300                 btrfs_remove_free_space_cache(block_group);
3301                 ASSERT(block_group->cached != BTRFS_CACHE_STARTED);
3302                 ASSERT(list_empty(&block_group->dirty_list));
3303                 ASSERT(list_empty(&block_group->io_list));
3304                 ASSERT(list_empty(&block_group->bg_list));
3305                 ASSERT(atomic_read(&block_group->count) == 1);
3306                 btrfs_put_block_group(block_group);
3307
3308                 spin_lock(&info->block_group_cache_lock);
3309         }
3310         spin_unlock(&info->block_group_cache_lock);
3311
3312         /*
3313          * Now that all the block groups are freed, go through and free all the
3314          * space_info structs.  This is only called during the final stages of
3315          * unmount, and so we know nobody is using them.  We call
3316          * synchronize_rcu() once before we start, just to be on the safe side.
3317          */
3318         synchronize_rcu();
3319
3320         btrfs_release_global_block_rsv(info);
3321
3322         while (!list_empty(&info->space_info)) {
3323                 space_info = list_entry(info->space_info.next,
3324                                         struct btrfs_space_info,
3325                                         list);
3326
3327                 /*
3328                  * Do not hide this behind enospc_debug, this is actually
3329                  * important and indicates a real bug if this happens.
3330                  */
3331                 if (WARN_ON(space_info->bytes_pinned > 0 ||
3332                             space_info->bytes_reserved > 0 ||
3333                             space_info->bytes_may_use > 0))
3334                         btrfs_dump_space_info(info, space_info, 0, 0);
3335                 list_del(&space_info->list);
3336                 btrfs_sysfs_remove_space_info(space_info);
3337         }
3338         return 0;
3339 }