Loading...
Note: File does not exist in v4.6.
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 "volumes.h"
11#include "transaction.h"
12#include "ref-verify.h"
13#include "sysfs.h"
14#include "tree-log.h"
15#include "delalloc-space.h"
16#include "discard.h"
17#include "raid56.h"
18
19/*
20 * Return target flags in extended format or 0 if restripe for this chunk_type
21 * is not in progress
22 *
23 * Should be called with balance_lock held
24 */
25static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
26{
27 struct btrfs_balance_control *bctl = fs_info->balance_ctl;
28 u64 target = 0;
29
30 if (!bctl)
31 return 0;
32
33 if (flags & BTRFS_BLOCK_GROUP_DATA &&
34 bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
35 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
36 } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
37 bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
38 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
39 } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
40 bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
41 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
42 }
43
44 return target;
45}
46
47/*
48 * @flags: available profiles in extended format (see ctree.h)
49 *
50 * Return reduced profile in chunk format. If profile changing is in progress
51 * (either running or paused) picks the target profile (if it's already
52 * available), otherwise falls back to plain reducing.
53 */
54static u64 btrfs_reduce_alloc_profile(struct btrfs_fs_info *fs_info, u64 flags)
55{
56 u64 num_devices = fs_info->fs_devices->rw_devices;
57 u64 target;
58 u64 raid_type;
59 u64 allowed = 0;
60
61 /*
62 * See if restripe for this chunk_type is in progress, if so try to
63 * reduce to the target profile
64 */
65 spin_lock(&fs_info->balance_lock);
66 target = get_restripe_target(fs_info, flags);
67 if (target) {
68 spin_unlock(&fs_info->balance_lock);
69 return extended_to_chunk(target);
70 }
71 spin_unlock(&fs_info->balance_lock);
72
73 /* First, mask out the RAID levels which aren't possible */
74 for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
75 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
76 allowed |= btrfs_raid_array[raid_type].bg_flag;
77 }
78 allowed &= flags;
79
80 if (allowed & BTRFS_BLOCK_GROUP_RAID6)
81 allowed = BTRFS_BLOCK_GROUP_RAID6;
82 else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
83 allowed = BTRFS_BLOCK_GROUP_RAID5;
84 else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
85 allowed = BTRFS_BLOCK_GROUP_RAID10;
86 else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
87 allowed = BTRFS_BLOCK_GROUP_RAID1;
88 else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
89 allowed = BTRFS_BLOCK_GROUP_RAID0;
90
91 flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
92
93 return extended_to_chunk(flags | allowed);
94}
95
96u64 btrfs_get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags)
97{
98 unsigned seq;
99 u64 flags;
100
101 do {
102 flags = orig_flags;
103 seq = read_seqbegin(&fs_info->profiles_lock);
104
105 if (flags & BTRFS_BLOCK_GROUP_DATA)
106 flags |= fs_info->avail_data_alloc_bits;
107 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
108 flags |= fs_info->avail_system_alloc_bits;
109 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
110 flags |= fs_info->avail_metadata_alloc_bits;
111 } while (read_seqretry(&fs_info->profiles_lock, seq));
112
113 return btrfs_reduce_alloc_profile(fs_info, flags);
114}
115
116void btrfs_get_block_group(struct btrfs_block_group *cache)
117{
118 refcount_inc(&cache->refs);
119}
120
121void btrfs_put_block_group(struct btrfs_block_group *cache)
122{
123 if (refcount_dec_and_test(&cache->refs)) {
124 WARN_ON(cache->pinned > 0);
125 WARN_ON(cache->reserved > 0);
126
127 /*
128 * A block_group shouldn't be on the discard_list anymore.
129 * Remove the block_group from the discard_list to prevent us
130 * from causing a panic due to NULL pointer dereference.
131 */
132 if (WARN_ON(!list_empty(&cache->discard_list)))
133 btrfs_discard_cancel_work(&cache->fs_info->discard_ctl,
134 cache);
135
136 /*
137 * If not empty, someone is still holding mutex of
138 * full_stripe_lock, which can only be released by caller.
139 * And it will definitely cause use-after-free when caller
140 * tries to release full stripe lock.
141 *
142 * No better way to resolve, but only to warn.
143 */
144 WARN_ON(!RB_EMPTY_ROOT(&cache->full_stripe_locks_root.root));
145 kfree(cache->free_space_ctl);
146 kfree(cache);
147 }
148}
149
150/*
151 * This adds the block group to the fs_info rb tree for the block group cache
152 */
153static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
154 struct btrfs_block_group *block_group)
155{
156 struct rb_node **p;
157 struct rb_node *parent = NULL;
158 struct btrfs_block_group *cache;
159
160 ASSERT(block_group->length != 0);
161
162 spin_lock(&info->block_group_cache_lock);
163 p = &info->block_group_cache_tree.rb_node;
164
165 while (*p) {
166 parent = *p;
167 cache = rb_entry(parent, struct btrfs_block_group, cache_node);
168 if (block_group->start < cache->start) {
169 p = &(*p)->rb_left;
170 } else if (block_group->start > cache->start) {
171 p = &(*p)->rb_right;
172 } else {
173 spin_unlock(&info->block_group_cache_lock);
174 return -EEXIST;
175 }
176 }
177
178 rb_link_node(&block_group->cache_node, parent, p);
179 rb_insert_color(&block_group->cache_node,
180 &info->block_group_cache_tree);
181
182 if (info->first_logical_byte > block_group->start)
183 info->first_logical_byte = block_group->start;
184
185 spin_unlock(&info->block_group_cache_lock);
186
187 return 0;
188}
189
190/*
191 * This will return the block group at or after bytenr if contains is 0, else
192 * it will return the block group that contains the bytenr
193 */
194static struct btrfs_block_group *block_group_cache_tree_search(
195 struct btrfs_fs_info *info, u64 bytenr, int contains)
196{
197 struct btrfs_block_group *cache, *ret = NULL;
198 struct rb_node *n;
199 u64 end, start;
200
201 spin_lock(&info->block_group_cache_lock);
202 n = info->block_group_cache_tree.rb_node;
203
204 while (n) {
205 cache = rb_entry(n, struct btrfs_block_group, cache_node);
206 end = cache->start + cache->length - 1;
207 start = cache->start;
208
209 if (bytenr < start) {
210 if (!contains && (!ret || start < ret->start))
211 ret = cache;
212 n = n->rb_left;
213 } else if (bytenr > start) {
214 if (contains && bytenr <= end) {
215 ret = cache;
216 break;
217 }
218 n = n->rb_right;
219 } else {
220 ret = cache;
221 break;
222 }
223 }
224 if (ret) {
225 btrfs_get_block_group(ret);
226 if (bytenr == 0 && info->first_logical_byte > ret->start)
227 info->first_logical_byte = ret->start;
228 }
229 spin_unlock(&info->block_group_cache_lock);
230
231 return ret;
232}
233
234/*
235 * Return the block group that starts at or after bytenr
236 */
237struct btrfs_block_group *btrfs_lookup_first_block_group(
238 struct btrfs_fs_info *info, u64 bytenr)
239{
240 return block_group_cache_tree_search(info, bytenr, 0);
241}
242
243/*
244 * Return the block group that contains the given bytenr
245 */
246struct btrfs_block_group *btrfs_lookup_block_group(
247 struct btrfs_fs_info *info, u64 bytenr)
248{
249 return block_group_cache_tree_search(info, bytenr, 1);
250}
251
252struct btrfs_block_group *btrfs_next_block_group(
253 struct btrfs_block_group *cache)
254{
255 struct btrfs_fs_info *fs_info = cache->fs_info;
256 struct rb_node *node;
257
258 spin_lock(&fs_info->block_group_cache_lock);
259
260 /* If our block group was removed, we need a full search. */
261 if (RB_EMPTY_NODE(&cache->cache_node)) {
262 const u64 next_bytenr = cache->start + cache->length;
263
264 spin_unlock(&fs_info->block_group_cache_lock);
265 btrfs_put_block_group(cache);
266 cache = btrfs_lookup_first_block_group(fs_info, next_bytenr); return cache;
267 }
268 node = rb_next(&cache->cache_node);
269 btrfs_put_block_group(cache);
270 if (node) {
271 cache = rb_entry(node, struct btrfs_block_group, cache_node);
272 btrfs_get_block_group(cache);
273 } else
274 cache = NULL;
275 spin_unlock(&fs_info->block_group_cache_lock);
276 return cache;
277}
278
279bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
280{
281 struct btrfs_block_group *bg;
282 bool ret = true;
283
284 bg = btrfs_lookup_block_group(fs_info, bytenr);
285 if (!bg)
286 return false;
287
288 spin_lock(&bg->lock);
289 if (bg->ro)
290 ret = false;
291 else
292 atomic_inc(&bg->nocow_writers);
293 spin_unlock(&bg->lock);
294
295 /* No put on block group, done by btrfs_dec_nocow_writers */
296 if (!ret)
297 btrfs_put_block_group(bg);
298
299 return ret;
300}
301
302void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
303{
304 struct btrfs_block_group *bg;
305
306 bg = btrfs_lookup_block_group(fs_info, bytenr);
307 ASSERT(bg);
308 if (atomic_dec_and_test(&bg->nocow_writers))
309 wake_up_var(&bg->nocow_writers);
310 /*
311 * Once for our lookup and once for the lookup done by a previous call
312 * to btrfs_inc_nocow_writers()
313 */
314 btrfs_put_block_group(bg);
315 btrfs_put_block_group(bg);
316}
317
318void btrfs_wait_nocow_writers(struct btrfs_block_group *bg)
319{
320 wait_var_event(&bg->nocow_writers, !atomic_read(&bg->nocow_writers));
321}
322
323void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
324 const u64 start)
325{
326 struct btrfs_block_group *bg;
327
328 bg = btrfs_lookup_block_group(fs_info, start);
329 ASSERT(bg);
330 if (atomic_dec_and_test(&bg->reservations))
331 wake_up_var(&bg->reservations);
332 btrfs_put_block_group(bg);
333}
334
335void btrfs_wait_block_group_reservations(struct btrfs_block_group *bg)
336{
337 struct btrfs_space_info *space_info = bg->space_info;
338
339 ASSERT(bg->ro);
340
341 if (!(bg->flags & BTRFS_BLOCK_GROUP_DATA))
342 return;
343
344 /*
345 * Our block group is read only but before we set it to read only,
346 * some task might have had allocated an extent from it already, but it
347 * has not yet created a respective ordered extent (and added it to a
348 * root's list of ordered extents).
349 * Therefore wait for any task currently allocating extents, since the
350 * block group's reservations counter is incremented while a read lock
351 * on the groups' semaphore is held and decremented after releasing
352 * the read access on that semaphore and creating the ordered extent.
353 */
354 down_write(&space_info->groups_sem);
355 up_write(&space_info->groups_sem);
356
357 wait_var_event(&bg->reservations, !atomic_read(&bg->reservations));
358}
359
360struct btrfs_caching_control *btrfs_get_caching_control(
361 struct btrfs_block_group *cache)
362{
363 struct btrfs_caching_control *ctl;
364
365 spin_lock(&cache->lock);
366 if (!cache->caching_ctl) {
367 spin_unlock(&cache->lock);
368 return NULL;
369 }
370
371 ctl = cache->caching_ctl;
372 refcount_inc(&ctl->count);
373 spin_unlock(&cache->lock);
374 return ctl;
375}
376
377void btrfs_put_caching_control(struct btrfs_caching_control *ctl)
378{
379 if (refcount_dec_and_test(&ctl->count))
380 kfree(ctl);
381}
382
383/*
384 * When we wait for progress in the block group caching, its because our
385 * allocation attempt failed at least once. So, we must sleep and let some
386 * progress happen before we try again.
387 *
388 * This function will sleep at least once waiting for new free space to show
389 * up, and then it will check the block group free space numbers for our min
390 * num_bytes. Another option is to have it go ahead and look in the rbtree for
391 * a free extent of a given size, but this is a good start.
392 *
393 * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
394 * any of the information in this block group.
395 */
396void btrfs_wait_block_group_cache_progress(struct btrfs_block_group *cache,
397 u64 num_bytes)
398{
399 struct btrfs_caching_control *caching_ctl;
400
401 caching_ctl = btrfs_get_caching_control(cache);
402 if (!caching_ctl)
403 return;
404
405 wait_event(caching_ctl->wait, btrfs_block_group_done(cache) ||
406 (cache->free_space_ctl->free_space >= num_bytes));
407
408 btrfs_put_caching_control(caching_ctl);
409}
410
411int btrfs_wait_block_group_cache_done(struct btrfs_block_group *cache)
412{
413 struct btrfs_caching_control *caching_ctl;
414 int ret = 0;
415
416 caching_ctl = btrfs_get_caching_control(cache);
417 if (!caching_ctl)
418 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
419
420 wait_event(caching_ctl->wait, btrfs_block_group_done(cache));
421 if (cache->cached == BTRFS_CACHE_ERROR)
422 ret = -EIO;
423 btrfs_put_caching_control(caching_ctl);
424 return ret;
425}
426
427#ifdef CONFIG_BTRFS_DEBUG
428static void fragment_free_space(struct btrfs_block_group *block_group)
429{
430 struct btrfs_fs_info *fs_info = block_group->fs_info;
431 u64 start = block_group->start;
432 u64 len = block_group->length;
433 u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ?
434 fs_info->nodesize : fs_info->sectorsize;
435 u64 step = chunk << 1;
436
437 while (len > chunk) {
438 btrfs_remove_free_space(block_group, start, chunk);
439 start += step;
440 if (len < step)
441 len = 0;
442 else
443 len -= step;
444 }
445}
446#endif
447
448/*
449 * This is only called by btrfs_cache_block_group, since we could have freed
450 * extents we need to check the pinned_extents for any extents that can't be
451 * used yet since their free space will be released as soon as the transaction
452 * commits.
453 */
454u64 add_new_free_space(struct btrfs_block_group *block_group, u64 start, u64 end)
455{
456 struct btrfs_fs_info *info = block_group->fs_info;
457 u64 extent_start, extent_end, size, total_added = 0;
458 int ret;
459
460 while (start < end) {
461 ret = find_first_extent_bit(&info->excluded_extents, start,
462 &extent_start, &extent_end,
463 EXTENT_DIRTY | EXTENT_UPTODATE,
464 NULL);
465 if (ret)
466 break;
467
468 if (extent_start <= start) {
469 start = extent_end + 1;
470 } else if (extent_start > start && extent_start < end) {
471 size = extent_start - start;
472 total_added += size;
473 ret = btrfs_add_free_space_async_trimmed(block_group,
474 start, size);
475 BUG_ON(ret); /* -ENOMEM or logic error */
476 start = extent_end + 1;
477 } else {
478 break;
479 }
480 }
481
482 if (start < end) {
483 size = end - start;
484 total_added += size;
485 ret = btrfs_add_free_space_async_trimmed(block_group, start,
486 size);
487 BUG_ON(ret); /* -ENOMEM or logic error */
488 }
489
490 return total_added;
491}
492
493static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl)
494{
495 struct btrfs_block_group *block_group = caching_ctl->block_group;
496 struct btrfs_fs_info *fs_info = block_group->fs_info;
497 struct btrfs_root *extent_root = fs_info->extent_root;
498 struct btrfs_path *path;
499 struct extent_buffer *leaf;
500 struct btrfs_key key;
501 u64 total_found = 0;
502 u64 last = 0;
503 u32 nritems;
504 int ret;
505 bool wakeup = true;
506
507 path = btrfs_alloc_path();
508 if (!path)
509 return -ENOMEM;
510
511 last = max_t(u64, block_group->start, BTRFS_SUPER_INFO_OFFSET);
512
513#ifdef CONFIG_BTRFS_DEBUG
514 /*
515 * If we're fragmenting we don't want to make anybody think we can
516 * allocate from this block group until we've had a chance to fragment
517 * the free space.
518 */
519 if (btrfs_should_fragment_free_space(block_group))
520 wakeup = false;
521#endif
522 /*
523 * We don't want to deadlock with somebody trying to allocate a new
524 * extent for the extent root while also trying to search the extent
525 * root to add free space. So we skip locking and search the commit
526 * root, since its read-only
527 */
528 path->skip_locking = 1;
529 path->search_commit_root = 1;
530 path->reada = READA_FORWARD;
531
532 key.objectid = last;
533 key.offset = 0;
534 key.type = BTRFS_EXTENT_ITEM_KEY;
535
536next:
537 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
538 if (ret < 0)
539 goto out;
540
541 leaf = path->nodes[0];
542 nritems = btrfs_header_nritems(leaf);
543
544 while (1) {
545 if (btrfs_fs_closing(fs_info) > 1) {
546 last = (u64)-1;
547 break;
548 }
549
550 if (path->slots[0] < nritems) {
551 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
552 } else {
553 ret = btrfs_find_next_key(extent_root, path, &key, 0, 0);
554 if (ret)
555 break;
556
557 if (need_resched() ||
558 rwsem_is_contended(&fs_info->commit_root_sem)) {
559 if (wakeup)
560 caching_ctl->progress = last;
561 btrfs_release_path(path);
562 up_read(&fs_info->commit_root_sem);
563 mutex_unlock(&caching_ctl->mutex);
564 cond_resched();
565 mutex_lock(&caching_ctl->mutex);
566 down_read(&fs_info->commit_root_sem);
567 goto next;
568 }
569
570 ret = btrfs_next_leaf(extent_root, path);
571 if (ret < 0)
572 goto out;
573 if (ret)
574 break;
575 leaf = path->nodes[0];
576 nritems = btrfs_header_nritems(leaf);
577 continue;
578 }
579
580 if (key.objectid < last) {
581 key.objectid = last;
582 key.offset = 0;
583 key.type = BTRFS_EXTENT_ITEM_KEY;
584
585 if (wakeup)
586 caching_ctl->progress = last;
587 btrfs_release_path(path);
588 goto next;
589 }
590
591 if (key.objectid < block_group->start) {
592 path->slots[0]++;
593 continue;
594 }
595
596 if (key.objectid >= block_group->start + block_group->length)
597 break;
598
599 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
600 key.type == BTRFS_METADATA_ITEM_KEY) {
601 total_found += add_new_free_space(block_group, last,
602 key.objectid);
603 if (key.type == BTRFS_METADATA_ITEM_KEY)
604 last = key.objectid +
605 fs_info->nodesize;
606 else
607 last = key.objectid + key.offset;
608
609 if (total_found > CACHING_CTL_WAKE_UP) {
610 total_found = 0;
611 if (wakeup)
612 wake_up(&caching_ctl->wait);
613 }
614 }
615 path->slots[0]++;
616 }
617 ret = 0;
618
619 total_found += add_new_free_space(block_group, last,
620 block_group->start + block_group->length);
621 caching_ctl->progress = (u64)-1;
622
623out:
624 btrfs_free_path(path);
625 return ret;
626}
627
628static noinline void caching_thread(struct btrfs_work *work)
629{
630 struct btrfs_block_group *block_group;
631 struct btrfs_fs_info *fs_info;
632 struct btrfs_caching_control *caching_ctl;
633 int ret;
634
635 caching_ctl = container_of(work, struct btrfs_caching_control, work);
636 block_group = caching_ctl->block_group;
637 fs_info = block_group->fs_info;
638
639 mutex_lock(&caching_ctl->mutex);
640 down_read(&fs_info->commit_root_sem);
641
642 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
643 ret = load_free_space_tree(caching_ctl);
644 else
645 ret = load_extent_tree_free(caching_ctl);
646
647 spin_lock(&block_group->lock);
648 block_group->caching_ctl = NULL;
649 block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED;
650 spin_unlock(&block_group->lock);
651
652#ifdef CONFIG_BTRFS_DEBUG
653 if (btrfs_should_fragment_free_space(block_group)) {
654 u64 bytes_used;
655
656 spin_lock(&block_group->space_info->lock);
657 spin_lock(&block_group->lock);
658 bytes_used = block_group->length - block_group->used;
659 block_group->space_info->bytes_used += bytes_used >> 1;
660 spin_unlock(&block_group->lock);
661 spin_unlock(&block_group->space_info->lock);
662 fragment_free_space(block_group);
663 }
664#endif
665
666 caching_ctl->progress = (u64)-1;
667
668 up_read(&fs_info->commit_root_sem);
669 btrfs_free_excluded_extents(block_group);
670 mutex_unlock(&caching_ctl->mutex);
671
672 wake_up(&caching_ctl->wait);
673
674 btrfs_put_caching_control(caching_ctl);
675 btrfs_put_block_group(block_group);
676}
677
678int btrfs_cache_block_group(struct btrfs_block_group *cache, int load_cache_only)
679{
680 DEFINE_WAIT(wait);
681 struct btrfs_fs_info *fs_info = cache->fs_info;
682 struct btrfs_caching_control *caching_ctl;
683 int ret = 0;
684
685 caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
686 if (!caching_ctl)
687 return -ENOMEM;
688
689 INIT_LIST_HEAD(&caching_ctl->list);
690 mutex_init(&caching_ctl->mutex);
691 init_waitqueue_head(&caching_ctl->wait);
692 caching_ctl->block_group = cache;
693 caching_ctl->progress = cache->start;
694 refcount_set(&caching_ctl->count, 1);
695 btrfs_init_work(&caching_ctl->work, caching_thread, NULL, NULL);
696
697 spin_lock(&cache->lock);
698 /*
699 * This should be a rare occasion, but this could happen I think in the
700 * case where one thread starts to load the space cache info, and then
701 * some other thread starts a transaction commit which tries to do an
702 * allocation while the other thread is still loading the space cache
703 * info. The previous loop should have kept us from choosing this block
704 * group, but if we've moved to the state where we will wait on caching
705 * block groups we need to first check if we're doing a fast load here,
706 * so we can wait for it to finish, otherwise we could end up allocating
707 * from a block group who's cache gets evicted for one reason or
708 * another.
709 */
710 while (cache->cached == BTRFS_CACHE_FAST) {
711 struct btrfs_caching_control *ctl;
712
713 ctl = cache->caching_ctl;
714 refcount_inc(&ctl->count);
715 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
716 spin_unlock(&cache->lock);
717
718 schedule();
719
720 finish_wait(&ctl->wait, &wait);
721 btrfs_put_caching_control(ctl);
722 spin_lock(&cache->lock);
723 }
724
725 if (cache->cached != BTRFS_CACHE_NO) {
726 spin_unlock(&cache->lock);
727 kfree(caching_ctl);
728 return 0;
729 }
730 WARN_ON(cache->caching_ctl);
731 cache->caching_ctl = caching_ctl;
732 cache->cached = BTRFS_CACHE_FAST;
733 spin_unlock(&cache->lock);
734
735 if (btrfs_test_opt(fs_info, SPACE_CACHE)) {
736 mutex_lock(&caching_ctl->mutex);
737 ret = load_free_space_cache(cache);
738
739 spin_lock(&cache->lock);
740 if (ret == 1) {
741 cache->caching_ctl = NULL;
742 cache->cached = BTRFS_CACHE_FINISHED;
743 cache->last_byte_to_unpin = (u64)-1;
744 caching_ctl->progress = (u64)-1;
745 } else {
746 if (load_cache_only) {
747 cache->caching_ctl = NULL;
748 cache->cached = BTRFS_CACHE_NO;
749 } else {
750 cache->cached = BTRFS_CACHE_STARTED;
751 cache->has_caching_ctl = 1;
752 }
753 }
754 spin_unlock(&cache->lock);
755#ifdef CONFIG_BTRFS_DEBUG
756 if (ret == 1 &&
757 btrfs_should_fragment_free_space(cache)) {
758 u64 bytes_used;
759
760 spin_lock(&cache->space_info->lock);
761 spin_lock(&cache->lock);
762 bytes_used = cache->length - cache->used;
763 cache->space_info->bytes_used += bytes_used >> 1;
764 spin_unlock(&cache->lock);
765 spin_unlock(&cache->space_info->lock);
766 fragment_free_space(cache);
767 }
768#endif
769 mutex_unlock(&caching_ctl->mutex);
770
771 wake_up(&caching_ctl->wait);
772 if (ret == 1) {
773 btrfs_put_caching_control(caching_ctl);
774 btrfs_free_excluded_extents(cache);
775 return 0;
776 }
777 } else {
778 /*
779 * We're either using the free space tree or no caching at all.
780 * Set cached to the appropriate value and wakeup any waiters.
781 */
782 spin_lock(&cache->lock);
783 if (load_cache_only) {
784 cache->caching_ctl = NULL;
785 cache->cached = BTRFS_CACHE_NO;
786 } else {
787 cache->cached = BTRFS_CACHE_STARTED;
788 cache->has_caching_ctl = 1;
789 }
790 spin_unlock(&cache->lock);
791 wake_up(&caching_ctl->wait);
792 }
793
794 if (load_cache_only) {
795 btrfs_put_caching_control(caching_ctl);
796 return 0;
797 }
798
799 down_write(&fs_info->commit_root_sem);
800 refcount_inc(&caching_ctl->count);
801 list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
802 up_write(&fs_info->commit_root_sem);
803
804 btrfs_get_block_group(cache);
805
806 btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
807
808 return ret;
809}
810
811static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
812{
813 u64 extra_flags = chunk_to_extended(flags) &
814 BTRFS_EXTENDED_PROFILE_MASK;
815
816 write_seqlock(&fs_info->profiles_lock);
817 if (flags & BTRFS_BLOCK_GROUP_DATA)
818 fs_info->avail_data_alloc_bits &= ~extra_flags;
819 if (flags & BTRFS_BLOCK_GROUP_METADATA)
820 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
821 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
822 fs_info->avail_system_alloc_bits &= ~extra_flags;
823 write_sequnlock(&fs_info->profiles_lock);
824}
825
826/*
827 * Clear incompat bits for the following feature(s):
828 *
829 * - RAID56 - in case there's neither RAID5 nor RAID6 profile block group
830 * in the whole filesystem
831 *
832 * - RAID1C34 - same as above for RAID1C3 and RAID1C4 block groups
833 */
834static void clear_incompat_bg_bits(struct btrfs_fs_info *fs_info, u64 flags)
835{
836 bool found_raid56 = false;
837 bool found_raid1c34 = false;
838
839 if ((flags & BTRFS_BLOCK_GROUP_RAID56_MASK) ||
840 (flags & BTRFS_BLOCK_GROUP_RAID1C3) ||
841 (flags & BTRFS_BLOCK_GROUP_RAID1C4)) {
842 struct list_head *head = &fs_info->space_info;
843 struct btrfs_space_info *sinfo;
844
845 list_for_each_entry_rcu(sinfo, head, list) {
846 down_read(&sinfo->groups_sem);
847 if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID5]))
848 found_raid56 = true;
849 if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID6]))
850 found_raid56 = true;
851 if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID1C3]))
852 found_raid1c34 = true;
853 if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID1C4]))
854 found_raid1c34 = true;
855 up_read(&sinfo->groups_sem);
856 }
857 if (!found_raid56)
858 btrfs_clear_fs_incompat(fs_info, RAID56);
859 if (!found_raid1c34)
860 btrfs_clear_fs_incompat(fs_info, RAID1C34);
861 }
862}
863
864static int remove_block_group_item(struct btrfs_trans_handle *trans,
865 struct btrfs_path *path,
866 struct btrfs_block_group *block_group)
867{
868 struct btrfs_fs_info *fs_info = trans->fs_info;
869 struct btrfs_root *root;
870 struct btrfs_key key;
871 int ret;
872
873 root = fs_info->extent_root;
874 key.objectid = block_group->start;
875 key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
876 key.offset = block_group->length;
877
878 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
879 if (ret > 0)
880 ret = -ENOENT;
881 if (ret < 0)
882 return ret;
883
884 ret = btrfs_del_item(trans, root, path);
885 return ret;
886}
887
888int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
889 u64 group_start, struct extent_map *em)
890{
891 struct btrfs_fs_info *fs_info = trans->fs_info;
892 struct btrfs_path *path;
893 struct btrfs_block_group *block_group;
894 struct btrfs_free_cluster *cluster;
895 struct btrfs_root *tree_root = fs_info->tree_root;
896 struct btrfs_key key;
897 struct inode *inode;
898 struct kobject *kobj = NULL;
899 int ret;
900 int index;
901 int factor;
902 struct btrfs_caching_control *caching_ctl = NULL;
903 bool remove_em;
904 bool remove_rsv = false;
905
906 block_group = btrfs_lookup_block_group(fs_info, group_start);
907 BUG_ON(!block_group);
908 BUG_ON(!block_group->ro);
909
910 trace_btrfs_remove_block_group(block_group);
911 /*
912 * Free the reserved super bytes from this block group before
913 * remove it.
914 */
915 btrfs_free_excluded_extents(block_group);
916 btrfs_free_ref_tree_range(fs_info, block_group->start,
917 block_group->length);
918
919 index = btrfs_bg_flags_to_raid_index(block_group->flags);
920 factor = btrfs_bg_type_to_factor(block_group->flags);
921
922 /* make sure this block group isn't part of an allocation cluster */
923 cluster = &fs_info->data_alloc_cluster;
924 spin_lock(&cluster->refill_lock);
925 btrfs_return_cluster_to_free_space(block_group, cluster);
926 spin_unlock(&cluster->refill_lock);
927
928 /*
929 * make sure this block group isn't part of a metadata
930 * allocation cluster
931 */
932 cluster = &fs_info->meta_alloc_cluster;
933 spin_lock(&cluster->refill_lock);
934 btrfs_return_cluster_to_free_space(block_group, cluster);
935 spin_unlock(&cluster->refill_lock);
936
937 path = btrfs_alloc_path();
938 if (!path) {
939 ret = -ENOMEM;
940 goto out;
941 }
942
943 /*
944 * get the inode first so any iput calls done for the io_list
945 * aren't the final iput (no unlinks allowed now)
946 */
947 inode = lookup_free_space_inode(block_group, path);
948
949 mutex_lock(&trans->transaction->cache_write_mutex);
950 /*
951 * Make sure our free space cache IO is done before removing the
952 * free space inode
953 */
954 spin_lock(&trans->transaction->dirty_bgs_lock);
955 if (!list_empty(&block_group->io_list)) {
956 list_del_init(&block_group->io_list);
957
958 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
959
960 spin_unlock(&trans->transaction->dirty_bgs_lock);
961 btrfs_wait_cache_io(trans, block_group, path);
962 btrfs_put_block_group(block_group);
963 spin_lock(&trans->transaction->dirty_bgs_lock);
964 }
965
966 if (!list_empty(&block_group->dirty_list)) {
967 list_del_init(&block_group->dirty_list);
968 remove_rsv = true;
969 btrfs_put_block_group(block_group);
970 }
971 spin_unlock(&trans->transaction->dirty_bgs_lock);
972 mutex_unlock(&trans->transaction->cache_write_mutex);
973
974 if (!IS_ERR(inode)) {
975 ret = btrfs_orphan_add(trans, BTRFS_I(inode));
976 if (ret) {
977 btrfs_add_delayed_iput(inode);
978 goto out;
979 }
980 clear_nlink(inode);
981 /* One for the block groups ref */
982 spin_lock(&block_group->lock);
983 if (block_group->iref) {
984 block_group->iref = 0;
985 block_group->inode = NULL;
986 spin_unlock(&block_group->lock);
987 iput(inode);
988 } else {
989 spin_unlock(&block_group->lock);
990 }
991 /* One for our lookup ref */
992 btrfs_add_delayed_iput(inode);
993 }
994
995 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
996 key.type = 0;
997 key.offset = block_group->start;
998
999 ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
1000 if (ret < 0)
1001 goto out;
1002 if (ret > 0)
1003 btrfs_release_path(path);
1004 if (ret == 0) {
1005 ret = btrfs_del_item(trans, tree_root, path);
1006 if (ret)
1007 goto out;
1008 btrfs_release_path(path);
1009 }
1010
1011 spin_lock(&fs_info->block_group_cache_lock);
1012 rb_erase(&block_group->cache_node,
1013 &fs_info->block_group_cache_tree);
1014 RB_CLEAR_NODE(&block_group->cache_node);
1015
1016 /* Once for the block groups rbtree */
1017 btrfs_put_block_group(block_group);
1018
1019 if (fs_info->first_logical_byte == block_group->start)
1020 fs_info->first_logical_byte = (u64)-1;
1021 spin_unlock(&fs_info->block_group_cache_lock);
1022
1023 down_write(&block_group->space_info->groups_sem);
1024 /*
1025 * we must use list_del_init so people can check to see if they
1026 * are still on the list after taking the semaphore
1027 */
1028 list_del_init(&block_group->list);
1029 if (list_empty(&block_group->space_info->block_groups[index])) {
1030 kobj = block_group->space_info->block_group_kobjs[index];
1031 block_group->space_info->block_group_kobjs[index] = NULL;
1032 clear_avail_alloc_bits(fs_info, block_group->flags);
1033 }
1034 up_write(&block_group->space_info->groups_sem);
1035 clear_incompat_bg_bits(fs_info, block_group->flags);
1036 if (kobj) {
1037 kobject_del(kobj);
1038 kobject_put(kobj);
1039 }
1040
1041 if (block_group->has_caching_ctl)
1042 caching_ctl = btrfs_get_caching_control(block_group);
1043 if (block_group->cached == BTRFS_CACHE_STARTED)
1044 btrfs_wait_block_group_cache_done(block_group);
1045 if (block_group->has_caching_ctl) {
1046 down_write(&fs_info->commit_root_sem);
1047 if (!caching_ctl) {
1048 struct btrfs_caching_control *ctl;
1049
1050 list_for_each_entry(ctl,
1051 &fs_info->caching_block_groups, list)
1052 if (ctl->block_group == block_group) {
1053 caching_ctl = ctl;
1054 refcount_inc(&caching_ctl->count);
1055 break;
1056 }
1057 }
1058 if (caching_ctl)
1059 list_del_init(&caching_ctl->list);
1060 up_write(&fs_info->commit_root_sem);
1061 if (caching_ctl) {
1062 /* Once for the caching bgs list and once for us. */
1063 btrfs_put_caching_control(caching_ctl);
1064 btrfs_put_caching_control(caching_ctl);
1065 }
1066 }
1067
1068 spin_lock(&trans->transaction->dirty_bgs_lock);
1069 WARN_ON(!list_empty(&block_group->dirty_list));
1070 WARN_ON(!list_empty(&block_group->io_list));
1071 spin_unlock(&trans->transaction->dirty_bgs_lock);
1072
1073 btrfs_remove_free_space_cache(block_group);
1074
1075 spin_lock(&block_group->space_info->lock);
1076 list_del_init(&block_group->ro_list);
1077
1078 if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
1079 WARN_ON(block_group->space_info->total_bytes
1080 < block_group->length);
1081 WARN_ON(block_group->space_info->bytes_readonly
1082 < block_group->length);
1083 WARN_ON(block_group->space_info->disk_total
1084 < block_group->length * factor);
1085 }
1086 block_group->space_info->total_bytes -= block_group->length;
1087 block_group->space_info->bytes_readonly -= block_group->length;
1088 block_group->space_info->disk_total -= block_group->length * factor;
1089
1090 spin_unlock(&block_group->space_info->lock);
1091
1092 /*
1093 * Remove the free space for the block group from the free space tree
1094 * and the block group's item from the extent tree before marking the
1095 * block group as removed. This is to prevent races with tasks that
1096 * freeze and unfreeze a block group, this task and another task
1097 * allocating a new block group - the unfreeze task ends up removing
1098 * the block group's extent map before the task calling this function
1099 * deletes the block group item from the extent tree, allowing for
1100 * another task to attempt to create another block group with the same
1101 * item key (and failing with -EEXIST and a transaction abort).
1102 */
1103 ret = remove_block_group_free_space(trans, block_group);
1104 if (ret)
1105 goto out;
1106
1107 ret = remove_block_group_item(trans, path, block_group);
1108 if (ret < 0)
1109 goto out;
1110
1111 spin_lock(&block_group->lock);
1112 block_group->removed = 1;
1113 /*
1114 * At this point trimming or scrub can't start on this block group,
1115 * because we removed the block group from the rbtree
1116 * fs_info->block_group_cache_tree so no one can't find it anymore and
1117 * even if someone already got this block group before we removed it
1118 * from the rbtree, they have already incremented block_group->frozen -
1119 * if they didn't, for the trimming case they won't find any free space
1120 * entries because we already removed them all when we called
1121 * btrfs_remove_free_space_cache().
1122 *
1123 * And we must not remove the extent map from the fs_info->mapping_tree
1124 * to prevent the same logical address range and physical device space
1125 * ranges from being reused for a new block group. This is needed to
1126 * avoid races with trimming and scrub.
1127 *
1128 * An fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
1129 * completely transactionless, so while it is trimming a range the
1130 * currently running transaction might finish and a new one start,
1131 * allowing for new block groups to be created that can reuse the same
1132 * physical device locations unless we take this special care.
1133 *
1134 * There may also be an implicit trim operation if the file system
1135 * is mounted with -odiscard. The same protections must remain
1136 * in place until the extents have been discarded completely when
1137 * the transaction commit has completed.
1138 */
1139 remove_em = (atomic_read(&block_group->frozen) == 0);
1140 spin_unlock(&block_group->lock);
1141
1142 if (remove_em) {
1143 struct extent_map_tree *em_tree;
1144
1145 em_tree = &fs_info->mapping_tree;
1146 write_lock(&em_tree->lock);
1147 remove_extent_mapping(em_tree, em);
1148 write_unlock(&em_tree->lock);
1149 /* once for the tree */
1150 free_extent_map(em);
1151 }
1152
1153out:
1154 /* Once for the lookup reference */
1155 btrfs_put_block_group(block_group);
1156 if (remove_rsv)
1157 btrfs_delayed_refs_rsv_release(fs_info, 1);
1158 btrfs_free_path(path);
1159 return ret;
1160}
1161
1162struct btrfs_trans_handle *btrfs_start_trans_remove_block_group(
1163 struct btrfs_fs_info *fs_info, const u64 chunk_offset)
1164{
1165 struct extent_map_tree *em_tree = &fs_info->mapping_tree;
1166 struct extent_map *em;
1167 struct map_lookup *map;
1168 unsigned int num_items;
1169
1170 read_lock(&em_tree->lock);
1171 em = lookup_extent_mapping(em_tree, chunk_offset, 1);
1172 read_unlock(&em_tree->lock);
1173 ASSERT(em && em->start == chunk_offset);
1174
1175 /*
1176 * We need to reserve 3 + N units from the metadata space info in order
1177 * to remove a block group (done at btrfs_remove_chunk() and at
1178 * btrfs_remove_block_group()), which are used for:
1179 *
1180 * 1 unit for adding the free space inode's orphan (located in the tree
1181 * of tree roots).
1182 * 1 unit for deleting the block group item (located in the extent
1183 * tree).
1184 * 1 unit for deleting the free space item (located in tree of tree
1185 * roots).
1186 * N units for deleting N device extent items corresponding to each
1187 * stripe (located in the device tree).
1188 *
1189 * In order to remove a block group we also need to reserve units in the
1190 * system space info in order to update the chunk tree (update one or
1191 * more device items and remove one chunk item), but this is done at
1192 * btrfs_remove_chunk() through a call to check_system_chunk().
1193 */
1194 map = em->map_lookup;
1195 num_items = 3 + map->num_stripes;
1196 free_extent_map(em);
1197
1198 return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
1199 num_items);
1200}
1201
1202/*
1203 * Mark block group @cache read-only, so later write won't happen to block
1204 * group @cache.
1205 *
1206 * If @force is not set, this function will only mark the block group readonly
1207 * if we have enough free space (1M) in other metadata/system block groups.
1208 * If @force is not set, this function will mark the block group readonly
1209 * without checking free space.
1210 *
1211 * NOTE: This function doesn't care if other block groups can contain all the
1212 * data in this block group. That check should be done by relocation routine,
1213 * not this function.
1214 */
1215static int inc_block_group_ro(struct btrfs_block_group *cache, int force)
1216{
1217 struct btrfs_space_info *sinfo = cache->space_info;
1218 u64 num_bytes;
1219 int ret = -ENOSPC;
1220
1221 spin_lock(&sinfo->lock);
1222 spin_lock(&cache->lock);
1223
1224 if (cache->ro) {
1225 cache->ro++;
1226 ret = 0;
1227 goto out;
1228 }
1229
1230 num_bytes = cache->length - cache->reserved - cache->pinned -
1231 cache->bytes_super - cache->used;
1232
1233 /*
1234 * Data never overcommits, even in mixed mode, so do just the straight
1235 * check of left over space in how much we have allocated.
1236 */
1237 if (force) {
1238 ret = 0;
1239 } else if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA) {
1240 u64 sinfo_used = btrfs_space_info_used(sinfo, true);
1241
1242 /*
1243 * Here we make sure if we mark this bg RO, we still have enough
1244 * free space as buffer.
1245 */
1246 if (sinfo_used + num_bytes <= sinfo->total_bytes)
1247 ret = 0;
1248 } else {
1249 /*
1250 * We overcommit metadata, so we need to do the
1251 * btrfs_can_overcommit check here, and we need to pass in
1252 * BTRFS_RESERVE_NO_FLUSH to give ourselves the most amount of
1253 * leeway to allow us to mark this block group as read only.
1254 */
1255 if (btrfs_can_overcommit(cache->fs_info, sinfo, num_bytes,
1256 BTRFS_RESERVE_NO_FLUSH))
1257 ret = 0;
1258 }
1259
1260 if (!ret) {
1261 sinfo->bytes_readonly += num_bytes;
1262 cache->ro++;
1263 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
1264 }
1265out:
1266 spin_unlock(&cache->lock);
1267 spin_unlock(&sinfo->lock);
1268 if (ret == -ENOSPC && btrfs_test_opt(cache->fs_info, ENOSPC_DEBUG)) {
1269 btrfs_info(cache->fs_info,
1270 "unable to make block group %llu ro", cache->start);
1271 btrfs_dump_space_info(cache->fs_info, cache->space_info, 0, 0);
1272 }
1273 return ret;
1274}
1275
1276static bool clean_pinned_extents(struct btrfs_trans_handle *trans,
1277 struct btrfs_block_group *bg)
1278{
1279 struct btrfs_fs_info *fs_info = bg->fs_info;
1280 struct btrfs_transaction *prev_trans = NULL;
1281 const u64 start = bg->start;
1282 const u64 end = start + bg->length - 1;
1283 int ret;
1284
1285 spin_lock(&fs_info->trans_lock);
1286 if (trans->transaction->list.prev != &fs_info->trans_list) {
1287 prev_trans = list_last_entry(&trans->transaction->list,
1288 struct btrfs_transaction, list);
1289 refcount_inc(&prev_trans->use_count);
1290 }
1291 spin_unlock(&fs_info->trans_lock);
1292
1293 /*
1294 * Hold the unused_bg_unpin_mutex lock to avoid racing with
1295 * btrfs_finish_extent_commit(). If we are at transaction N, another
1296 * task might be running finish_extent_commit() for the previous
1297 * transaction N - 1, and have seen a range belonging to the block
1298 * group in pinned_extents before we were able to clear the whole block
1299 * group range from pinned_extents. This means that task can lookup for
1300 * the block group after we unpinned it from pinned_extents and removed
1301 * it, leading to a BUG_ON() at unpin_extent_range().
1302 */
1303 mutex_lock(&fs_info->unused_bg_unpin_mutex);
1304 if (prev_trans) {
1305 ret = clear_extent_bits(&prev_trans->pinned_extents, start, end,
1306 EXTENT_DIRTY);
1307 if (ret)
1308 goto out;
1309 }
1310
1311 ret = clear_extent_bits(&trans->transaction->pinned_extents, start, end,
1312 EXTENT_DIRTY);
1313out:
1314 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
1315 if (prev_trans)
1316 btrfs_put_transaction(prev_trans);
1317
1318 return ret == 0;
1319}
1320
1321/*
1322 * Process the unused_bgs list and remove any that don't have any allocated
1323 * space inside of them.
1324 */
1325void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
1326{
1327 struct btrfs_block_group *block_group;
1328 struct btrfs_space_info *space_info;
1329 struct btrfs_trans_handle *trans;
1330 const bool async_trim_enabled = btrfs_test_opt(fs_info, DISCARD_ASYNC);
1331 int ret = 0;
1332
1333 if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
1334 return;
1335
1336 spin_lock(&fs_info->unused_bgs_lock);
1337 while (!list_empty(&fs_info->unused_bgs)) {
1338 int trimming;
1339
1340 block_group = list_first_entry(&fs_info->unused_bgs,
1341 struct btrfs_block_group,
1342 bg_list);
1343 list_del_init(&block_group->bg_list);
1344
1345 space_info = block_group->space_info;
1346
1347 if (ret || btrfs_mixed_space_info(space_info)) {
1348 btrfs_put_block_group(block_group);
1349 continue;
1350 }
1351 spin_unlock(&fs_info->unused_bgs_lock);
1352
1353 btrfs_discard_cancel_work(&fs_info->discard_ctl, block_group);
1354
1355 mutex_lock(&fs_info->delete_unused_bgs_mutex);
1356
1357 /* Don't want to race with allocators so take the groups_sem */
1358 down_write(&space_info->groups_sem);
1359
1360 /*
1361 * Async discard moves the final block group discard to be prior
1362 * to the unused_bgs code path. Therefore, if it's not fully
1363 * trimmed, punt it back to the async discard lists.
1364 */
1365 if (btrfs_test_opt(fs_info, DISCARD_ASYNC) &&
1366 !btrfs_is_free_space_trimmed(block_group)) {
1367 trace_btrfs_skip_unused_block_group(block_group);
1368 up_write(&space_info->groups_sem);
1369 /* Requeue if we failed because of async discard */
1370 btrfs_discard_queue_work(&fs_info->discard_ctl,
1371 block_group);
1372 goto next;
1373 }
1374
1375 spin_lock(&block_group->lock);
1376 if (block_group->reserved || block_group->pinned ||
1377 block_group->used || block_group->ro ||
1378 list_is_singular(&block_group->list)) {
1379 /*
1380 * We want to bail if we made new allocations or have
1381 * outstanding allocations in this block group. We do
1382 * the ro check in case balance is currently acting on
1383 * this block group.
1384 */
1385 trace_btrfs_skip_unused_block_group(block_group);
1386 spin_unlock(&block_group->lock);
1387 up_write(&space_info->groups_sem);
1388 goto next;
1389 }
1390 spin_unlock(&block_group->lock);
1391
1392 /* We don't want to force the issue, only flip if it's ok. */
1393 ret = inc_block_group_ro(block_group, 0);
1394 up_write(&space_info->groups_sem);
1395 if (ret < 0) {
1396 ret = 0;
1397 goto next;
1398 }
1399
1400 /*
1401 * Want to do this before we do anything else so we can recover
1402 * properly if we fail to join the transaction.
1403 */
1404 trans = btrfs_start_trans_remove_block_group(fs_info,
1405 block_group->start);
1406 if (IS_ERR(trans)) {
1407 btrfs_dec_block_group_ro(block_group);
1408 ret = PTR_ERR(trans);
1409 goto next;
1410 }
1411
1412 /*
1413 * We could have pending pinned extents for this block group,
1414 * just delete them, we don't care about them anymore.
1415 */
1416 if (!clean_pinned_extents(trans, block_group)) {
1417 btrfs_dec_block_group_ro(block_group);
1418 goto end_trans;
1419 }
1420
1421 /*
1422 * At this point, the block_group is read only and should fail
1423 * new allocations. However, btrfs_finish_extent_commit() can
1424 * cause this block_group to be placed back on the discard
1425 * lists because now the block_group isn't fully discarded.
1426 * Bail here and try again later after discarding everything.
1427 */
1428 spin_lock(&fs_info->discard_ctl.lock);
1429 if (!list_empty(&block_group->discard_list)) {
1430 spin_unlock(&fs_info->discard_ctl.lock);
1431 btrfs_dec_block_group_ro(block_group);
1432 btrfs_discard_queue_work(&fs_info->discard_ctl,
1433 block_group);
1434 goto end_trans;
1435 }
1436 spin_unlock(&fs_info->discard_ctl.lock);
1437
1438 /* Reset pinned so btrfs_put_block_group doesn't complain */
1439 spin_lock(&space_info->lock);
1440 spin_lock(&block_group->lock);
1441
1442 btrfs_space_info_update_bytes_pinned(fs_info, space_info,
1443 -block_group->pinned);
1444 space_info->bytes_readonly += block_group->pinned;
1445 percpu_counter_add_batch(&space_info->total_bytes_pinned,
1446 -block_group->pinned,
1447 BTRFS_TOTAL_BYTES_PINNED_BATCH);
1448 block_group->pinned = 0;
1449
1450 spin_unlock(&block_group->lock);
1451 spin_unlock(&space_info->lock);
1452
1453 /*
1454 * The normal path here is an unused block group is passed here,
1455 * then trimming is handled in the transaction commit path.
1456 * Async discard interposes before this to do the trimming
1457 * before coming down the unused block group path as trimming
1458 * will no longer be done later in the transaction commit path.
1459 */
1460 if (!async_trim_enabled && btrfs_test_opt(fs_info, DISCARD_ASYNC))
1461 goto flip_async;
1462
1463 /* DISCARD can flip during remount */
1464 trimming = btrfs_test_opt(fs_info, DISCARD_SYNC);
1465
1466 /* Implicit trim during transaction commit. */
1467 if (trimming)
1468 btrfs_freeze_block_group(block_group);
1469
1470 /*
1471 * Btrfs_remove_chunk will abort the transaction if things go
1472 * horribly wrong.
1473 */
1474 ret = btrfs_remove_chunk(trans, block_group->start);
1475
1476 if (ret) {
1477 if (trimming)
1478 btrfs_unfreeze_block_group(block_group);
1479 goto end_trans;
1480 }
1481
1482 /*
1483 * If we're not mounted with -odiscard, we can just forget
1484 * about this block group. Otherwise we'll need to wait
1485 * until transaction commit to do the actual discard.
1486 */
1487 if (trimming) {
1488 spin_lock(&fs_info->unused_bgs_lock);
1489 /*
1490 * A concurrent scrub might have added us to the list
1491 * fs_info->unused_bgs, so use a list_move operation
1492 * to add the block group to the deleted_bgs list.
1493 */
1494 list_move(&block_group->bg_list,
1495 &trans->transaction->deleted_bgs);
1496 spin_unlock(&fs_info->unused_bgs_lock);
1497 btrfs_get_block_group(block_group);
1498 }
1499end_trans:
1500 btrfs_end_transaction(trans);
1501next:
1502 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
1503 btrfs_put_block_group(block_group);
1504 spin_lock(&fs_info->unused_bgs_lock);
1505 }
1506 spin_unlock(&fs_info->unused_bgs_lock);
1507 return;
1508
1509flip_async:
1510 btrfs_end_transaction(trans);
1511 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
1512 btrfs_put_block_group(block_group);
1513 btrfs_discard_punt_unused_bgs_list(fs_info);
1514}
1515
1516void btrfs_mark_bg_unused(struct btrfs_block_group *bg)
1517{
1518 struct btrfs_fs_info *fs_info = bg->fs_info;
1519
1520 spin_lock(&fs_info->unused_bgs_lock);
1521 if (list_empty(&bg->bg_list)) {
1522 btrfs_get_block_group(bg);
1523 trace_btrfs_add_unused_block_group(bg);
1524 list_add_tail(&bg->bg_list, &fs_info->unused_bgs);
1525 }
1526 spin_unlock(&fs_info->unused_bgs_lock);
1527}
1528
1529static int read_bg_from_eb(struct btrfs_fs_info *fs_info, struct btrfs_key *key,
1530 struct btrfs_path *path)
1531{
1532 struct extent_map_tree *em_tree;
1533 struct extent_map *em;
1534 struct btrfs_block_group_item bg;
1535 struct extent_buffer *leaf;
1536 int slot;
1537 u64 flags;
1538 int ret = 0;
1539
1540 slot = path->slots[0];
1541 leaf = path->nodes[0];
1542
1543 em_tree = &fs_info->mapping_tree;
1544 read_lock(&em_tree->lock);
1545 em = lookup_extent_mapping(em_tree, key->objectid, key->offset);
1546 read_unlock(&em_tree->lock);
1547 if (!em) {
1548 btrfs_err(fs_info,
1549 "logical %llu len %llu found bg but no related chunk",
1550 key->objectid, key->offset);
1551 return -ENOENT;
1552 }
1553
1554 if (em->start != key->objectid || em->len != key->offset) {
1555 btrfs_err(fs_info,
1556 "block group %llu len %llu mismatch with chunk %llu len %llu",
1557 key->objectid, key->offset, em->start, em->len);
1558 ret = -EUCLEAN;
1559 goto out_free_em;
1560 }
1561
1562 read_extent_buffer(leaf, &bg, btrfs_item_ptr_offset(leaf, slot),
1563 sizeof(bg));
1564 flags = btrfs_stack_block_group_flags(&bg) &
1565 BTRFS_BLOCK_GROUP_TYPE_MASK;
1566
1567 if (flags != (em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK)) {
1568 btrfs_err(fs_info,
1569"block group %llu len %llu type flags 0x%llx mismatch with chunk type flags 0x%llx",
1570 key->objectid, key->offset, flags,
1571 (BTRFS_BLOCK_GROUP_TYPE_MASK & em->map_lookup->type));
1572 ret = -EUCLEAN;
1573 }
1574
1575out_free_em:
1576 free_extent_map(em);
1577 return ret;
1578}
1579
1580static int find_first_block_group(struct btrfs_fs_info *fs_info,
1581 struct btrfs_path *path,
1582 struct btrfs_key *key)
1583{
1584 struct btrfs_root *root = fs_info->extent_root;
1585 int ret;
1586 struct btrfs_key found_key;
1587 struct extent_buffer *leaf;
1588 int slot;
1589
1590 ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
1591 if (ret < 0)
1592 return ret;
1593
1594 while (1) {
1595 slot = path->slots[0];
1596 leaf = path->nodes[0];
1597 if (slot >= btrfs_header_nritems(leaf)) {
1598 ret = btrfs_next_leaf(root, path);
1599 if (ret == 0)
1600 continue;
1601 if (ret < 0)
1602 goto out;
1603 break;
1604 }
1605 btrfs_item_key_to_cpu(leaf, &found_key, slot);
1606
1607 if (found_key.objectid >= key->objectid &&
1608 found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
1609 ret = read_bg_from_eb(fs_info, &found_key, path);
1610 break;
1611 }
1612
1613 path->slots[0]++;
1614 }
1615out:
1616 return ret;
1617}
1618
1619static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
1620{
1621 u64 extra_flags = chunk_to_extended(flags) &
1622 BTRFS_EXTENDED_PROFILE_MASK;
1623
1624 write_seqlock(&fs_info->profiles_lock);
1625 if (flags & BTRFS_BLOCK_GROUP_DATA)
1626 fs_info->avail_data_alloc_bits |= extra_flags;
1627 if (flags & BTRFS_BLOCK_GROUP_METADATA)
1628 fs_info->avail_metadata_alloc_bits |= extra_flags;
1629 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
1630 fs_info->avail_system_alloc_bits |= extra_flags;
1631 write_sequnlock(&fs_info->profiles_lock);
1632}
1633
1634/**
1635 * btrfs_rmap_block - Map a physical disk address to a list of logical addresses
1636 * @chunk_start: logical address of block group
1637 * @physical: physical address to map to logical addresses
1638 * @logical: return array of logical addresses which map to @physical
1639 * @naddrs: length of @logical
1640 * @stripe_len: size of IO stripe for the given block group
1641 *
1642 * Maps a particular @physical disk address to a list of @logical addresses.
1643 * Used primarily to exclude those portions of a block group that contain super
1644 * block copies.
1645 */
1646EXPORT_FOR_TESTS
1647int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
1648 u64 physical, u64 **logical, int *naddrs, int *stripe_len)
1649{
1650 struct extent_map *em;
1651 struct map_lookup *map;
1652 u64 *buf;
1653 u64 bytenr;
1654 u64 data_stripe_length;
1655 u64 io_stripe_size;
1656 int i, nr = 0;
1657 int ret = 0;
1658
1659 em = btrfs_get_chunk_map(fs_info, chunk_start, 1);
1660 if (IS_ERR(em))
1661 return -EIO;
1662
1663 map = em->map_lookup;
1664 data_stripe_length = em->orig_block_len;
1665 io_stripe_size = map->stripe_len;
1666
1667 /* For RAID5/6 adjust to a full IO stripe length */
1668 if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
1669 io_stripe_size = map->stripe_len * nr_data_stripes(map);
1670
1671 buf = kcalloc(map->num_stripes, sizeof(u64), GFP_NOFS);
1672 if (!buf) {
1673 ret = -ENOMEM;
1674 goto out;
1675 }
1676
1677 for (i = 0; i < map->num_stripes; i++) {
1678 bool already_inserted = false;
1679 u64 stripe_nr;
1680 int j;
1681
1682 if (!in_range(physical, map->stripes[i].physical,
1683 data_stripe_length))
1684 continue;
1685
1686 stripe_nr = physical - map->stripes[i].physical;
1687 stripe_nr = div64_u64(stripe_nr, map->stripe_len);
1688
1689 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
1690 stripe_nr = stripe_nr * map->num_stripes + i;
1691 stripe_nr = div_u64(stripe_nr, map->sub_stripes);
1692 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
1693 stripe_nr = stripe_nr * map->num_stripes + i;
1694 }
1695 /*
1696 * The remaining case would be for RAID56, multiply by
1697 * nr_data_stripes(). Alternatively, just use rmap_len below
1698 * instead of map->stripe_len
1699 */
1700
1701 bytenr = chunk_start + stripe_nr * io_stripe_size;
1702
1703 /* Ensure we don't add duplicate addresses */
1704 for (j = 0; j < nr; j++) {
1705 if (buf[j] == bytenr) {
1706 already_inserted = true;
1707 break;
1708 }
1709 }
1710
1711 if (!already_inserted)
1712 buf[nr++] = bytenr;
1713 }
1714
1715 *logical = buf;
1716 *naddrs = nr;
1717 *stripe_len = io_stripe_size;
1718out:
1719 free_extent_map(em);
1720 return ret;
1721}
1722
1723static int exclude_super_stripes(struct btrfs_block_group *cache)
1724{
1725 struct btrfs_fs_info *fs_info = cache->fs_info;
1726 u64 bytenr;
1727 u64 *logical;
1728 int stripe_len;
1729 int i, nr, ret;
1730
1731 if (cache->start < BTRFS_SUPER_INFO_OFFSET) {
1732 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->start;
1733 cache->bytes_super += stripe_len;
1734 ret = btrfs_add_excluded_extent(fs_info, cache->start,
1735 stripe_len);
1736 if (ret)
1737 return ret;
1738 }
1739
1740 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
1741 bytenr = btrfs_sb_offset(i);
1742 ret = btrfs_rmap_block(fs_info, cache->start,
1743 bytenr, &logical, &nr, &stripe_len);
1744 if (ret)
1745 return ret;
1746
1747 while (nr--) {
1748 u64 len = min_t(u64, stripe_len,
1749 cache->start + cache->length - logical[nr]);
1750
1751 cache->bytes_super += len;
1752 ret = btrfs_add_excluded_extent(fs_info, logical[nr],
1753 len);
1754 if (ret) {
1755 kfree(logical);
1756 return ret;
1757 }
1758 }
1759
1760 kfree(logical);
1761 }
1762 return 0;
1763}
1764
1765static void link_block_group(struct btrfs_block_group *cache)
1766{
1767 struct btrfs_space_info *space_info = cache->space_info;
1768 int index = btrfs_bg_flags_to_raid_index(cache->flags);
1769 bool first = false;
1770
1771 down_write(&space_info->groups_sem);
1772 if (list_empty(&space_info->block_groups[index]))
1773 first = true;
1774 list_add_tail(&cache->list, &space_info->block_groups[index]);
1775 up_write(&space_info->groups_sem);
1776
1777 if (first)
1778 btrfs_sysfs_add_block_group_type(cache);
1779}
1780
1781static struct btrfs_block_group *btrfs_create_block_group_cache(
1782 struct btrfs_fs_info *fs_info, u64 start)
1783{
1784 struct btrfs_block_group *cache;
1785
1786 cache = kzalloc(sizeof(*cache), GFP_NOFS);
1787 if (!cache)
1788 return NULL;
1789
1790 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
1791 GFP_NOFS);
1792 if (!cache->free_space_ctl) {
1793 kfree(cache);
1794 return NULL;
1795 }
1796
1797 cache->start = start;
1798
1799 cache->fs_info = fs_info;
1800 cache->full_stripe_len = btrfs_full_stripe_len(fs_info, start);
1801
1802 cache->discard_index = BTRFS_DISCARD_INDEX_UNUSED;
1803
1804 refcount_set(&cache->refs, 1);
1805 spin_lock_init(&cache->lock);
1806 init_rwsem(&cache->data_rwsem);
1807 INIT_LIST_HEAD(&cache->list);
1808 INIT_LIST_HEAD(&cache->cluster_list);
1809 INIT_LIST_HEAD(&cache->bg_list);
1810 INIT_LIST_HEAD(&cache->ro_list);
1811 INIT_LIST_HEAD(&cache->discard_list);
1812 INIT_LIST_HEAD(&cache->dirty_list);
1813 INIT_LIST_HEAD(&cache->io_list);
1814 btrfs_init_free_space_ctl(cache);
1815 atomic_set(&cache->frozen, 0);
1816 mutex_init(&cache->free_space_lock);
1817 btrfs_init_full_stripe_locks_tree(&cache->full_stripe_locks_root);
1818
1819 return cache;
1820}
1821
1822/*
1823 * Iterate all chunks and verify that each of them has the corresponding block
1824 * group
1825 */
1826static int check_chunk_block_group_mappings(struct btrfs_fs_info *fs_info)
1827{
1828 struct extent_map_tree *map_tree = &fs_info->mapping_tree;
1829 struct extent_map *em;
1830 struct btrfs_block_group *bg;
1831 u64 start = 0;
1832 int ret = 0;
1833
1834 while (1) {
1835 read_lock(&map_tree->lock);
1836 /*
1837 * lookup_extent_mapping will return the first extent map
1838 * intersecting the range, so setting @len to 1 is enough to
1839 * get the first chunk.
1840 */
1841 em = lookup_extent_mapping(map_tree, start, 1);
1842 read_unlock(&map_tree->lock);
1843 if (!em)
1844 break;
1845
1846 bg = btrfs_lookup_block_group(fs_info, em->start);
1847 if (!bg) {
1848 btrfs_err(fs_info,
1849 "chunk start=%llu len=%llu doesn't have corresponding block group",
1850 em->start, em->len);
1851 ret = -EUCLEAN;
1852 free_extent_map(em);
1853 break;
1854 }
1855 if (bg->start != em->start || bg->length != em->len ||
1856 (bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK) !=
1857 (em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK)) {
1858 btrfs_err(fs_info,
1859"chunk start=%llu len=%llu flags=0x%llx doesn't match block group start=%llu len=%llu flags=0x%llx",
1860 em->start, em->len,
1861 em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK,
1862 bg->start, bg->length,
1863 bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK);
1864 ret = -EUCLEAN;
1865 free_extent_map(em);
1866 btrfs_put_block_group(bg);
1867 break;
1868 }
1869 start = em->start + em->len;
1870 free_extent_map(em);
1871 btrfs_put_block_group(bg);
1872 }
1873 return ret;
1874}
1875
1876static int read_block_group_item(struct btrfs_block_group *cache,
1877 struct btrfs_path *path,
1878 const struct btrfs_key *key)
1879{
1880 struct extent_buffer *leaf = path->nodes[0];
1881 struct btrfs_block_group_item bgi;
1882 int slot = path->slots[0];
1883
1884 cache->length = key->offset;
1885
1886 read_extent_buffer(leaf, &bgi, btrfs_item_ptr_offset(leaf, slot),
1887 sizeof(bgi));
1888 cache->used = btrfs_stack_block_group_used(&bgi);
1889 cache->flags = btrfs_stack_block_group_flags(&bgi);
1890
1891 return 0;
1892}
1893
1894static int read_one_block_group(struct btrfs_fs_info *info,
1895 struct btrfs_path *path,
1896 const struct btrfs_key *key,
1897 int need_clear)
1898{
1899 struct btrfs_block_group *cache;
1900 struct btrfs_space_info *space_info;
1901 const bool mixed = btrfs_fs_incompat(info, MIXED_GROUPS);
1902 int ret;
1903
1904 ASSERT(key->type == BTRFS_BLOCK_GROUP_ITEM_KEY);
1905
1906 cache = btrfs_create_block_group_cache(info, key->objectid);
1907 if (!cache)
1908 return -ENOMEM;
1909
1910 ret = read_block_group_item(cache, path, key);
1911 if (ret < 0)
1912 goto error;
1913
1914 set_free_space_tree_thresholds(cache);
1915
1916 if (need_clear) {
1917 /*
1918 * When we mount with old space cache, we need to
1919 * set BTRFS_DC_CLEAR and set dirty flag.
1920 *
1921 * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
1922 * truncate the old free space cache inode and
1923 * setup a new one.
1924 * b) Setting 'dirty flag' makes sure that we flush
1925 * the new space cache info onto disk.
1926 */
1927 if (btrfs_test_opt(info, SPACE_CACHE))
1928 cache->disk_cache_state = BTRFS_DC_CLEAR;
1929 }
1930 if (!mixed && ((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
1931 (cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
1932 btrfs_err(info,
1933"bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
1934 cache->start);
1935 ret = -EINVAL;
1936 goto error;
1937 }
1938
1939 /*
1940 * We need to exclude the super stripes now so that the space info has
1941 * super bytes accounted for, otherwise we'll think we have more space
1942 * than we actually do.
1943 */
1944 ret = exclude_super_stripes(cache);
1945 if (ret) {
1946 /* We may have excluded something, so call this just in case. */
1947 btrfs_free_excluded_extents(cache);
1948 goto error;
1949 }
1950
1951 /*
1952 * Check for two cases, either we are full, and therefore don't need
1953 * to bother with the caching work since we won't find any space, or we
1954 * are empty, and we can just add all the space in and be done with it.
1955 * This saves us _a_lot_ of time, particularly in the full case.
1956 */
1957 if (cache->length == cache->used) {
1958 cache->last_byte_to_unpin = (u64)-1;
1959 cache->cached = BTRFS_CACHE_FINISHED;
1960 btrfs_free_excluded_extents(cache);
1961 } else if (cache->used == 0) {
1962 cache->last_byte_to_unpin = (u64)-1;
1963 cache->cached = BTRFS_CACHE_FINISHED;
1964 add_new_free_space(cache, cache->start,
1965 cache->start + cache->length);
1966 btrfs_free_excluded_extents(cache);
1967 }
1968
1969 ret = btrfs_add_block_group_cache(info, cache);
1970 if (ret) {
1971 btrfs_remove_free_space_cache(cache);
1972 goto error;
1973 }
1974 trace_btrfs_add_block_group(info, cache, 0);
1975 btrfs_update_space_info(info, cache->flags, cache->length,
1976 cache->used, cache->bytes_super, &space_info);
1977
1978 cache->space_info = space_info;
1979
1980 link_block_group(cache);
1981
1982 set_avail_alloc_bits(info, cache->flags);
1983 if (btrfs_chunk_readonly(info, cache->start)) {
1984 inc_block_group_ro(cache, 1);
1985 } else if (cache->used == 0) {
1986 ASSERT(list_empty(&cache->bg_list));
1987 if (btrfs_test_opt(info, DISCARD_ASYNC))
1988 btrfs_discard_queue_work(&info->discard_ctl, cache);
1989 else
1990 btrfs_mark_bg_unused(cache);
1991 }
1992 return 0;
1993error:
1994 btrfs_put_block_group(cache);
1995 return ret;
1996}
1997
1998int btrfs_read_block_groups(struct btrfs_fs_info *info)
1999{
2000 struct btrfs_path *path;
2001 int ret;
2002 struct btrfs_block_group *cache;
2003 struct btrfs_space_info *space_info;
2004 struct btrfs_key key;
2005 int need_clear = 0;
2006 u64 cache_gen;
2007
2008 key.objectid = 0;
2009 key.offset = 0;
2010 key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
2011 path = btrfs_alloc_path();
2012 if (!path)
2013 return -ENOMEM;
2014
2015 cache_gen = btrfs_super_cache_generation(info->super_copy);
2016 if (btrfs_test_opt(info, SPACE_CACHE) &&
2017 btrfs_super_generation(info->super_copy) != cache_gen)
2018 need_clear = 1;
2019 if (btrfs_test_opt(info, CLEAR_CACHE))
2020 need_clear = 1;
2021
2022 while (1) {
2023 ret = find_first_block_group(info, path, &key);
2024 if (ret > 0)
2025 break;
2026 if (ret != 0)
2027 goto error;
2028
2029 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
2030 ret = read_one_block_group(info, path, &key, need_clear);
2031 if (ret < 0)
2032 goto error;
2033 key.objectid += key.offset;
2034 key.offset = 0;
2035 btrfs_release_path(path);
2036 }
2037
2038 rcu_read_lock();
2039 list_for_each_entry_rcu(space_info, &info->space_info, list) {
2040 if (!(btrfs_get_alloc_profile(info, space_info->flags) &
2041 (BTRFS_BLOCK_GROUP_RAID10 |
2042 BTRFS_BLOCK_GROUP_RAID1_MASK |
2043 BTRFS_BLOCK_GROUP_RAID56_MASK |
2044 BTRFS_BLOCK_GROUP_DUP)))
2045 continue;
2046 /*
2047 * Avoid allocating from un-mirrored block group if there are
2048 * mirrored block groups.
2049 */
2050 list_for_each_entry(cache,
2051 &space_info->block_groups[BTRFS_RAID_RAID0],
2052 list)
2053 inc_block_group_ro(cache, 1);
2054 list_for_each_entry(cache,
2055 &space_info->block_groups[BTRFS_RAID_SINGLE],
2056 list)
2057 inc_block_group_ro(cache, 1);
2058 }
2059 rcu_read_unlock();
2060
2061 btrfs_init_global_block_rsv(info);
2062 ret = check_chunk_block_group_mappings(info);
2063error:
2064 btrfs_free_path(path);
2065 return ret;
2066}
2067
2068static int insert_block_group_item(struct btrfs_trans_handle *trans,
2069 struct btrfs_block_group *block_group)
2070{
2071 struct btrfs_fs_info *fs_info = trans->fs_info;
2072 struct btrfs_block_group_item bgi;
2073 struct btrfs_root *root;
2074 struct btrfs_key key;
2075
2076 spin_lock(&block_group->lock);
2077 btrfs_set_stack_block_group_used(&bgi, block_group->used);
2078 btrfs_set_stack_block_group_chunk_objectid(&bgi,
2079 BTRFS_FIRST_CHUNK_TREE_OBJECTID);
2080 btrfs_set_stack_block_group_flags(&bgi, block_group->flags);
2081 key.objectid = block_group->start;
2082 key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
2083 key.offset = block_group->length;
2084 spin_unlock(&block_group->lock);
2085
2086 root = fs_info->extent_root;
2087 return btrfs_insert_item(trans, root, &key, &bgi, sizeof(bgi));
2088}
2089
2090void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans)
2091{
2092 struct btrfs_fs_info *fs_info = trans->fs_info;
2093 struct btrfs_block_group *block_group;
2094 int ret = 0;
2095
2096 if (!trans->can_flush_pending_bgs)
2097 return;
2098
2099 while (!list_empty(&trans->new_bgs)) {
2100 block_group = list_first_entry(&trans->new_bgs,
2101 struct btrfs_block_group,
2102 bg_list);
2103 if (ret)
2104 goto next;
2105
2106 ret = insert_block_group_item(trans, block_group);
2107 if (ret)
2108 btrfs_abort_transaction(trans, ret);
2109 ret = btrfs_finish_chunk_alloc(trans, block_group->start,
2110 block_group->length);
2111 if (ret)
2112 btrfs_abort_transaction(trans, ret);
2113 add_block_group_free_space(trans, block_group);
2114 /* Already aborted the transaction if it failed. */
2115next:
2116 btrfs_delayed_refs_rsv_release(fs_info, 1);
2117 list_del_init(&block_group->bg_list);
2118 }
2119 btrfs_trans_release_chunk_metadata(trans);
2120}
2121
2122int btrfs_make_block_group(struct btrfs_trans_handle *trans, u64 bytes_used,
2123 u64 type, u64 chunk_offset, u64 size)
2124{
2125 struct btrfs_fs_info *fs_info = trans->fs_info;
2126 struct btrfs_block_group *cache;
2127 int ret;
2128
2129 btrfs_set_log_full_commit(trans);
2130
2131 cache = btrfs_create_block_group_cache(fs_info, chunk_offset);
2132 if (!cache)
2133 return -ENOMEM;
2134
2135 cache->length = size;
2136 set_free_space_tree_thresholds(cache);
2137 cache->used = bytes_used;
2138 cache->flags = type;
2139 cache->last_byte_to_unpin = (u64)-1;
2140 cache->cached = BTRFS_CACHE_FINISHED;
2141 cache->needs_free_space = 1;
2142 ret = exclude_super_stripes(cache);
2143 if (ret) {
2144 /* We may have excluded something, so call this just in case */
2145 btrfs_free_excluded_extents(cache);
2146 btrfs_put_block_group(cache);
2147 return ret;
2148 }
2149
2150 add_new_free_space(cache, chunk_offset, chunk_offset + size);
2151
2152 btrfs_free_excluded_extents(cache);
2153
2154#ifdef CONFIG_BTRFS_DEBUG
2155 if (btrfs_should_fragment_free_space(cache)) {
2156 u64 new_bytes_used = size - bytes_used;
2157
2158 bytes_used += new_bytes_used >> 1;
2159 fragment_free_space(cache);
2160 }
2161#endif
2162 /*
2163 * Ensure the corresponding space_info object is created and
2164 * assigned to our block group. We want our bg to be added to the rbtree
2165 * with its ->space_info set.
2166 */
2167 cache->space_info = btrfs_find_space_info(fs_info, cache->flags);
2168 ASSERT(cache->space_info);
2169
2170 ret = btrfs_add_block_group_cache(fs_info, cache);
2171 if (ret) {
2172 btrfs_remove_free_space_cache(cache);
2173 btrfs_put_block_group(cache);
2174 return ret;
2175 }
2176
2177 /*
2178 * Now that our block group has its ->space_info set and is inserted in
2179 * the rbtree, update the space info's counters.
2180 */
2181 trace_btrfs_add_block_group(fs_info, cache, 1);
2182 btrfs_update_space_info(fs_info, cache->flags, size, bytes_used,
2183 cache->bytes_super, &cache->space_info);
2184 btrfs_update_global_block_rsv(fs_info);
2185
2186 link_block_group(cache);
2187
2188 list_add_tail(&cache->bg_list, &trans->new_bgs);
2189 trans->delayed_ref_updates++;
2190 btrfs_update_delayed_refs_rsv(trans);
2191
2192 set_avail_alloc_bits(fs_info, type);
2193 return 0;
2194}
2195
2196/*
2197 * Mark one block group RO, can be called several times for the same block
2198 * group.
2199 *
2200 * @cache: the destination block group
2201 * @do_chunk_alloc: whether need to do chunk pre-allocation, this is to
2202 * ensure we still have some free space after marking this
2203 * block group RO.
2204 */
2205int btrfs_inc_block_group_ro(struct btrfs_block_group *cache,
2206 bool do_chunk_alloc)
2207{
2208 struct btrfs_fs_info *fs_info = cache->fs_info;
2209 struct btrfs_trans_handle *trans;
2210 u64 alloc_flags;
2211 int ret;
2212
2213again:
2214 trans = btrfs_join_transaction(fs_info->extent_root);
2215 if (IS_ERR(trans))
2216 return PTR_ERR(trans);
2217
2218 /*
2219 * we're not allowed to set block groups readonly after the dirty
2220 * block groups cache has started writing. If it already started,
2221 * back off and let this transaction commit
2222 */
2223 mutex_lock(&fs_info->ro_block_group_mutex);
2224 if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
2225 u64 transid = trans->transid;
2226
2227 mutex_unlock(&fs_info->ro_block_group_mutex);
2228 btrfs_end_transaction(trans);
2229
2230 ret = btrfs_wait_for_commit(fs_info, transid);
2231 if (ret)
2232 return ret;
2233 goto again;
2234 }
2235
2236 if (do_chunk_alloc) {
2237 /*
2238 * If we are changing raid levels, try to allocate a
2239 * corresponding block group with the new raid level.
2240 */
2241 alloc_flags = btrfs_get_alloc_profile(fs_info, cache->flags);
2242 if (alloc_flags != cache->flags) {
2243 ret = btrfs_chunk_alloc(trans, alloc_flags,
2244 CHUNK_ALLOC_FORCE);
2245 /*
2246 * ENOSPC is allowed here, we may have enough space
2247 * already allocated at the new raid level to carry on
2248 */
2249 if (ret == -ENOSPC)
2250 ret = 0;
2251 if (ret < 0)
2252 goto out;
2253 }
2254 }
2255
2256 ret = inc_block_group_ro(cache, 0);
2257 if (!do_chunk_alloc)
2258 goto unlock_out;
2259 if (!ret)
2260 goto out;
2261 alloc_flags = btrfs_get_alloc_profile(fs_info, cache->space_info->flags);
2262 ret = btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
2263 if (ret < 0)
2264 goto out;
2265 ret = inc_block_group_ro(cache, 0);
2266out:
2267 if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
2268 alloc_flags = btrfs_get_alloc_profile(fs_info, cache->flags);
2269 mutex_lock(&fs_info->chunk_mutex);
2270 check_system_chunk(trans, alloc_flags);
2271 mutex_unlock(&fs_info->chunk_mutex);
2272 }
2273unlock_out:
2274 mutex_unlock(&fs_info->ro_block_group_mutex);
2275
2276 btrfs_end_transaction(trans);
2277 return ret;
2278}
2279
2280void btrfs_dec_block_group_ro(struct btrfs_block_group *cache)
2281{
2282 struct btrfs_space_info *sinfo = cache->space_info;
2283 u64 num_bytes;
2284
2285 BUG_ON(!cache->ro);
2286
2287 spin_lock(&sinfo->lock);
2288 spin_lock(&cache->lock);
2289 if (!--cache->ro) {
2290 num_bytes = cache->length - cache->reserved -
2291 cache->pinned - cache->bytes_super - cache->used;
2292 sinfo->bytes_readonly -= num_bytes;
2293 list_del_init(&cache->ro_list);
2294 }
2295 spin_unlock(&cache->lock);
2296 spin_unlock(&sinfo->lock);
2297}
2298
2299static int update_block_group_item(struct btrfs_trans_handle *trans,
2300 struct btrfs_path *path,
2301 struct btrfs_block_group *cache)
2302{
2303 struct btrfs_fs_info *fs_info = trans->fs_info;
2304 int ret;
2305 struct btrfs_root *root = fs_info->extent_root;
2306 unsigned long bi;
2307 struct extent_buffer *leaf;
2308 struct btrfs_block_group_item bgi;
2309 struct btrfs_key key;
2310
2311 key.objectid = cache->start;
2312 key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
2313 key.offset = cache->length;
2314
2315 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2316 if (ret) {
2317 if (ret > 0)
2318 ret = -ENOENT;
2319 goto fail;
2320 }
2321
2322 leaf = path->nodes[0];
2323 bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
2324 btrfs_set_stack_block_group_used(&bgi, cache->used);
2325 btrfs_set_stack_block_group_chunk_objectid(&bgi,
2326 BTRFS_FIRST_CHUNK_TREE_OBJECTID);
2327 btrfs_set_stack_block_group_flags(&bgi, cache->flags);
2328 write_extent_buffer(leaf, &bgi, bi, sizeof(bgi));
2329 btrfs_mark_buffer_dirty(leaf);
2330fail:
2331 btrfs_release_path(path);
2332 return ret;
2333
2334}
2335
2336static int cache_save_setup(struct btrfs_block_group *block_group,
2337 struct btrfs_trans_handle *trans,
2338 struct btrfs_path *path)
2339{
2340 struct btrfs_fs_info *fs_info = block_group->fs_info;
2341 struct btrfs_root *root = fs_info->tree_root;
2342 struct inode *inode = NULL;
2343 struct extent_changeset *data_reserved = NULL;
2344 u64 alloc_hint = 0;
2345 int dcs = BTRFS_DC_ERROR;
2346 u64 num_pages = 0;
2347 int retries = 0;
2348 int ret = 0;
2349
2350 /*
2351 * If this block group is smaller than 100 megs don't bother caching the
2352 * block group.
2353 */
2354 if (block_group->length < (100 * SZ_1M)) {
2355 spin_lock(&block_group->lock);
2356 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
2357 spin_unlock(&block_group->lock);
2358 return 0;
2359 }
2360
2361 if (TRANS_ABORTED(trans))
2362 return 0;
2363again:
2364 inode = lookup_free_space_inode(block_group, path);
2365 if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
2366 ret = PTR_ERR(inode);
2367 btrfs_release_path(path);
2368 goto out;
2369 }
2370
2371 if (IS_ERR(inode)) {
2372 BUG_ON(retries);
2373 retries++;
2374
2375 if (block_group->ro)
2376 goto out_free;
2377
2378 ret = create_free_space_inode(trans, block_group, path);
2379 if (ret)
2380 goto out_free;
2381 goto again;
2382 }
2383
2384 /*
2385 * We want to set the generation to 0, that way if anything goes wrong
2386 * from here on out we know not to trust this cache when we load up next
2387 * time.
2388 */
2389 BTRFS_I(inode)->generation = 0;
2390 ret = btrfs_update_inode(trans, root, inode);
2391 if (ret) {
2392 /*
2393 * So theoretically we could recover from this, simply set the
2394 * super cache generation to 0 so we know to invalidate the
2395 * cache, but then we'd have to keep track of the block groups
2396 * that fail this way so we know we _have_ to reset this cache
2397 * before the next commit or risk reading stale cache. So to
2398 * limit our exposure to horrible edge cases lets just abort the
2399 * transaction, this only happens in really bad situations
2400 * anyway.
2401 */
2402 btrfs_abort_transaction(trans, ret);
2403 goto out_put;
2404 }
2405 WARN_ON(ret);
2406
2407 /* We've already setup this transaction, go ahead and exit */
2408 if (block_group->cache_generation == trans->transid &&
2409 i_size_read(inode)) {
2410 dcs = BTRFS_DC_SETUP;
2411 goto out_put;
2412 }
2413
2414 if (i_size_read(inode) > 0) {
2415 ret = btrfs_check_trunc_cache_free_space(fs_info,
2416 &fs_info->global_block_rsv);
2417 if (ret)
2418 goto out_put;
2419
2420 ret = btrfs_truncate_free_space_cache(trans, NULL, inode);
2421 if (ret)
2422 goto out_put;
2423 }
2424
2425 spin_lock(&block_group->lock);
2426 if (block_group->cached != BTRFS_CACHE_FINISHED ||
2427 !btrfs_test_opt(fs_info, SPACE_CACHE)) {
2428 /*
2429 * don't bother trying to write stuff out _if_
2430 * a) we're not cached,
2431 * b) we're with nospace_cache mount option,
2432 * c) we're with v2 space_cache (FREE_SPACE_TREE).
2433 */
2434 dcs = BTRFS_DC_WRITTEN;
2435 spin_unlock(&block_group->lock);
2436 goto out_put;
2437 }
2438 spin_unlock(&block_group->lock);
2439
2440 /*
2441 * We hit an ENOSPC when setting up the cache in this transaction, just
2442 * skip doing the setup, we've already cleared the cache so we're safe.
2443 */
2444 if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
2445 ret = -ENOSPC;
2446 goto out_put;
2447 }
2448
2449 /*
2450 * Try to preallocate enough space based on how big the block group is.
2451 * Keep in mind this has to include any pinned space which could end up
2452 * taking up quite a bit since it's not folded into the other space
2453 * cache.
2454 */
2455 num_pages = div_u64(block_group->length, SZ_256M);
2456 if (!num_pages)
2457 num_pages = 1;
2458
2459 num_pages *= 16;
2460 num_pages *= PAGE_SIZE;
2461
2462 ret = btrfs_check_data_free_space(BTRFS_I(inode), &data_reserved, 0,
2463 num_pages);
2464 if (ret)
2465 goto out_put;
2466
2467 ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
2468 num_pages, num_pages,
2469 &alloc_hint);
2470 /*
2471 * Our cache requires contiguous chunks so that we don't modify a bunch
2472 * of metadata or split extents when writing the cache out, which means
2473 * we can enospc if we are heavily fragmented in addition to just normal
2474 * out of space conditions. So if we hit this just skip setting up any
2475 * other block groups for this transaction, maybe we'll unpin enough
2476 * space the next time around.
2477 */
2478 if (!ret)
2479 dcs = BTRFS_DC_SETUP;
2480 else if (ret == -ENOSPC)
2481 set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
2482
2483out_put:
2484 iput(inode);
2485out_free:
2486 btrfs_release_path(path);
2487out:
2488 spin_lock(&block_group->lock);
2489 if (!ret && dcs == BTRFS_DC_SETUP)
2490 block_group->cache_generation = trans->transid;
2491 block_group->disk_cache_state = dcs;
2492 spin_unlock(&block_group->lock);
2493
2494 extent_changeset_free(data_reserved);
2495 return ret;
2496}
2497
2498int btrfs_setup_space_cache(struct btrfs_trans_handle *trans)
2499{
2500 struct btrfs_fs_info *fs_info = trans->fs_info;
2501 struct btrfs_block_group *cache, *tmp;
2502 struct btrfs_transaction *cur_trans = trans->transaction;
2503 struct btrfs_path *path;
2504
2505 if (list_empty(&cur_trans->dirty_bgs) ||
2506 !btrfs_test_opt(fs_info, SPACE_CACHE))
2507 return 0;
2508
2509 path = btrfs_alloc_path();
2510 if (!path)
2511 return -ENOMEM;
2512
2513 /* Could add new block groups, use _safe just in case */
2514 list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
2515 dirty_list) {
2516 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
2517 cache_save_setup(cache, trans, path);
2518 }
2519
2520 btrfs_free_path(path);
2521 return 0;
2522}
2523
2524/*
2525 * Transaction commit does final block group cache writeback during a critical
2526 * section where nothing is allowed to change the FS. This is required in
2527 * order for the cache to actually match the block group, but can introduce a
2528 * lot of latency into the commit.
2529 *
2530 * So, btrfs_start_dirty_block_groups is here to kick off block group cache IO.
2531 * There's a chance we'll have to redo some of it if the block group changes
2532 * again during the commit, but it greatly reduces the commit latency by
2533 * getting rid of the easy block groups while we're still allowing others to
2534 * join the commit.
2535 */
2536int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans)
2537{
2538 struct btrfs_fs_info *fs_info = trans->fs_info;
2539 struct btrfs_block_group *cache;
2540 struct btrfs_transaction *cur_trans = trans->transaction;
2541 int ret = 0;
2542 int should_put;
2543 struct btrfs_path *path = NULL;
2544 LIST_HEAD(dirty);
2545 struct list_head *io = &cur_trans->io_bgs;
2546 int num_started = 0;
2547 int loops = 0;
2548
2549 spin_lock(&cur_trans->dirty_bgs_lock);
2550 if (list_empty(&cur_trans->dirty_bgs)) {
2551 spin_unlock(&cur_trans->dirty_bgs_lock);
2552 return 0;
2553 }
2554 list_splice_init(&cur_trans->dirty_bgs, &dirty);
2555 spin_unlock(&cur_trans->dirty_bgs_lock);
2556
2557again:
2558 /* Make sure all the block groups on our dirty list actually exist */
2559 btrfs_create_pending_block_groups(trans);
2560
2561 if (!path) {
2562 path = btrfs_alloc_path();
2563 if (!path)
2564 return -ENOMEM;
2565 }
2566
2567 /*
2568 * cache_write_mutex is here only to save us from balance or automatic
2569 * removal of empty block groups deleting this block group while we are
2570 * writing out the cache
2571 */
2572 mutex_lock(&trans->transaction->cache_write_mutex);
2573 while (!list_empty(&dirty)) {
2574 bool drop_reserve = true;
2575
2576 cache = list_first_entry(&dirty, struct btrfs_block_group,
2577 dirty_list);
2578 /*
2579 * This can happen if something re-dirties a block group that
2580 * is already under IO. Just wait for it to finish and then do
2581 * it all again
2582 */
2583 if (!list_empty(&cache->io_list)) {
2584 list_del_init(&cache->io_list);
2585 btrfs_wait_cache_io(trans, cache, path);
2586 btrfs_put_block_group(cache);
2587 }
2588
2589
2590 /*
2591 * btrfs_wait_cache_io uses the cache->dirty_list to decide if
2592 * it should update the cache_state. Don't delete until after
2593 * we wait.
2594 *
2595 * Since we're not running in the commit critical section
2596 * we need the dirty_bgs_lock to protect from update_block_group
2597 */
2598 spin_lock(&cur_trans->dirty_bgs_lock);
2599 list_del_init(&cache->dirty_list);
2600 spin_unlock(&cur_trans->dirty_bgs_lock);
2601
2602 should_put = 1;
2603
2604 cache_save_setup(cache, trans, path);
2605
2606 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
2607 cache->io_ctl.inode = NULL;
2608 ret = btrfs_write_out_cache(trans, cache, path);
2609 if (ret == 0 && cache->io_ctl.inode) {
2610 num_started++;
2611 should_put = 0;
2612
2613 /*
2614 * The cache_write_mutex is protecting the
2615 * io_list, also refer to the definition of
2616 * btrfs_transaction::io_bgs for more details
2617 */
2618 list_add_tail(&cache->io_list, io);
2619 } else {
2620 /*
2621 * If we failed to write the cache, the
2622 * generation will be bad and life goes on
2623 */
2624 ret = 0;
2625 }
2626 }
2627 if (!ret) {
2628 ret = update_block_group_item(trans, path, cache);
2629 /*
2630 * Our block group might still be attached to the list
2631 * of new block groups in the transaction handle of some
2632 * other task (struct btrfs_trans_handle->new_bgs). This
2633 * means its block group item isn't yet in the extent
2634 * tree. If this happens ignore the error, as we will
2635 * try again later in the critical section of the
2636 * transaction commit.
2637 */
2638 if (ret == -ENOENT) {
2639 ret = 0;
2640 spin_lock(&cur_trans->dirty_bgs_lock);
2641 if (list_empty(&cache->dirty_list)) {
2642 list_add_tail(&cache->dirty_list,
2643 &cur_trans->dirty_bgs);
2644 btrfs_get_block_group(cache);
2645 drop_reserve = false;
2646 }
2647 spin_unlock(&cur_trans->dirty_bgs_lock);
2648 } else if (ret) {
2649 btrfs_abort_transaction(trans, ret);
2650 }
2651 }
2652
2653 /* If it's not on the io list, we need to put the block group */
2654 if (should_put)
2655 btrfs_put_block_group(cache);
2656 if (drop_reserve)
2657 btrfs_delayed_refs_rsv_release(fs_info, 1);
2658
2659 if (ret)
2660 break;
2661
2662 /*
2663 * Avoid blocking other tasks for too long. It might even save
2664 * us from writing caches for block groups that are going to be
2665 * removed.
2666 */
2667 mutex_unlock(&trans->transaction->cache_write_mutex);
2668 mutex_lock(&trans->transaction->cache_write_mutex);
2669 }
2670 mutex_unlock(&trans->transaction->cache_write_mutex);
2671
2672 /*
2673 * Go through delayed refs for all the stuff we've just kicked off
2674 * and then loop back (just once)
2675 */
2676 ret = btrfs_run_delayed_refs(trans, 0);
2677 if (!ret && loops == 0) {
2678 loops++;
2679 spin_lock(&cur_trans->dirty_bgs_lock);
2680 list_splice_init(&cur_trans->dirty_bgs, &dirty);
2681 /*
2682 * dirty_bgs_lock protects us from concurrent block group
2683 * deletes too (not just cache_write_mutex).
2684 */
2685 if (!list_empty(&dirty)) {
2686 spin_unlock(&cur_trans->dirty_bgs_lock);
2687 goto again;
2688 }
2689 spin_unlock(&cur_trans->dirty_bgs_lock);
2690 } else if (ret < 0) {
2691 btrfs_cleanup_dirty_bgs(cur_trans, fs_info);
2692 }
2693
2694 btrfs_free_path(path);
2695 return ret;
2696}
2697
2698int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans)
2699{
2700 struct btrfs_fs_info *fs_info = trans->fs_info;
2701 struct btrfs_block_group *cache;
2702 struct btrfs_transaction *cur_trans = trans->transaction;
2703 int ret = 0;
2704 int should_put;
2705 struct btrfs_path *path;
2706 struct list_head *io = &cur_trans->io_bgs;
2707 int num_started = 0;
2708
2709 path = btrfs_alloc_path();
2710 if (!path)
2711 return -ENOMEM;
2712
2713 /*
2714 * Even though we are in the critical section of the transaction commit,
2715 * we can still have concurrent tasks adding elements to this
2716 * transaction's list of dirty block groups. These tasks correspond to
2717 * endio free space workers started when writeback finishes for a
2718 * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
2719 * allocate new block groups as a result of COWing nodes of the root
2720 * tree when updating the free space inode. The writeback for the space
2721 * caches is triggered by an earlier call to
2722 * btrfs_start_dirty_block_groups() and iterations of the following
2723 * loop.
2724 * Also we want to do the cache_save_setup first and then run the
2725 * delayed refs to make sure we have the best chance at doing this all
2726 * in one shot.
2727 */
2728 spin_lock(&cur_trans->dirty_bgs_lock);
2729 while (!list_empty(&cur_trans->dirty_bgs)) {
2730 cache = list_first_entry(&cur_trans->dirty_bgs,
2731 struct btrfs_block_group,
2732 dirty_list);
2733
2734 /*
2735 * This can happen if cache_save_setup re-dirties a block group
2736 * that is already under IO. Just wait for it to finish and
2737 * then do it all again
2738 */
2739 if (!list_empty(&cache->io_list)) {
2740 spin_unlock(&cur_trans->dirty_bgs_lock);
2741 list_del_init(&cache->io_list);
2742 btrfs_wait_cache_io(trans, cache, path);
2743 btrfs_put_block_group(cache);
2744 spin_lock(&cur_trans->dirty_bgs_lock);
2745 }
2746
2747 /*
2748 * Don't remove from the dirty list until after we've waited on
2749 * any pending IO
2750 */
2751 list_del_init(&cache->dirty_list);
2752 spin_unlock(&cur_trans->dirty_bgs_lock);
2753 should_put = 1;
2754
2755 cache_save_setup(cache, trans, path);
2756
2757 if (!ret)
2758 ret = btrfs_run_delayed_refs(trans,
2759 (unsigned long) -1);
2760
2761 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
2762 cache->io_ctl.inode = NULL;
2763 ret = btrfs_write_out_cache(trans, cache, path);
2764 if (ret == 0 && cache->io_ctl.inode) {
2765 num_started++;
2766 should_put = 0;
2767 list_add_tail(&cache->io_list, io);
2768 } else {
2769 /*
2770 * If we failed to write the cache, the
2771 * generation will be bad and life goes on
2772 */
2773 ret = 0;
2774 }
2775 }
2776 if (!ret) {
2777 ret = update_block_group_item(trans, path, cache);
2778 /*
2779 * One of the free space endio workers might have
2780 * created a new block group while updating a free space
2781 * cache's inode (at inode.c:btrfs_finish_ordered_io())
2782 * and hasn't released its transaction handle yet, in
2783 * which case the new block group is still attached to
2784 * its transaction handle and its creation has not
2785 * finished yet (no block group item in the extent tree
2786 * yet, etc). If this is the case, wait for all free
2787 * space endio workers to finish and retry. This is a
2788 * a very rare case so no need for a more efficient and
2789 * complex approach.
2790 */
2791 if (ret == -ENOENT) {
2792 wait_event(cur_trans->writer_wait,
2793 atomic_read(&cur_trans->num_writers) == 1);
2794 ret = update_block_group_item(trans, path, cache);
2795 }
2796 if (ret)
2797 btrfs_abort_transaction(trans, ret);
2798 }
2799
2800 /* If its not on the io list, we need to put the block group */
2801 if (should_put)
2802 btrfs_put_block_group(cache);
2803 btrfs_delayed_refs_rsv_release(fs_info, 1);
2804 spin_lock(&cur_trans->dirty_bgs_lock);
2805 }
2806 spin_unlock(&cur_trans->dirty_bgs_lock);
2807
2808 /*
2809 * Refer to the definition of io_bgs member for details why it's safe
2810 * to use it without any locking
2811 */
2812 while (!list_empty(io)) {
2813 cache = list_first_entry(io, struct btrfs_block_group,
2814 io_list);
2815 list_del_init(&cache->io_list);
2816 btrfs_wait_cache_io(trans, cache, path);
2817 btrfs_put_block_group(cache);
2818 }
2819
2820 btrfs_free_path(path);
2821 return ret;
2822}
2823
2824int btrfs_update_block_group(struct btrfs_trans_handle *trans,
2825 u64 bytenr, u64 num_bytes, int alloc)
2826{
2827 struct btrfs_fs_info *info = trans->fs_info;
2828 struct btrfs_block_group *cache = NULL;
2829 u64 total = num_bytes;
2830 u64 old_val;
2831 u64 byte_in_group;
2832 int factor;
2833 int ret = 0;
2834
2835 /* Block accounting for super block */
2836 spin_lock(&info->delalloc_root_lock);
2837 old_val = btrfs_super_bytes_used(info->super_copy);
2838 if (alloc)
2839 old_val += num_bytes;
2840 else
2841 old_val -= num_bytes;
2842 btrfs_set_super_bytes_used(info->super_copy, old_val);
2843 spin_unlock(&info->delalloc_root_lock);
2844
2845 while (total) {
2846 cache = btrfs_lookup_block_group(info, bytenr);
2847 if (!cache) {
2848 ret = -ENOENT;
2849 break;
2850 }
2851 factor = btrfs_bg_type_to_factor(cache->flags);
2852
2853 /*
2854 * If this block group has free space cache written out, we
2855 * need to make sure to load it if we are removing space. This
2856 * is because we need the unpinning stage to actually add the
2857 * space back to the block group, otherwise we will leak space.
2858 */
2859 if (!alloc && !btrfs_block_group_done(cache))
2860 btrfs_cache_block_group(cache, 1);
2861
2862 byte_in_group = bytenr - cache->start;
2863 WARN_ON(byte_in_group > cache->length);
2864
2865 spin_lock(&cache->space_info->lock);
2866 spin_lock(&cache->lock);
2867
2868 if (btrfs_test_opt(info, SPACE_CACHE) &&
2869 cache->disk_cache_state < BTRFS_DC_CLEAR)
2870 cache->disk_cache_state = BTRFS_DC_CLEAR;
2871
2872 old_val = cache->used;
2873 num_bytes = min(total, cache->length - byte_in_group);
2874 if (alloc) {
2875 old_val += num_bytes;
2876 cache->used = old_val;
2877 cache->reserved -= num_bytes;
2878 cache->space_info->bytes_reserved -= num_bytes;
2879 cache->space_info->bytes_used += num_bytes;
2880 cache->space_info->disk_used += num_bytes * factor;
2881 spin_unlock(&cache->lock);
2882 spin_unlock(&cache->space_info->lock);
2883 } else {
2884 old_val -= num_bytes;
2885 cache->used = old_val;
2886 cache->pinned += num_bytes;
2887 btrfs_space_info_update_bytes_pinned(info,
2888 cache->space_info, num_bytes);
2889 cache->space_info->bytes_used -= num_bytes;
2890 cache->space_info->disk_used -= num_bytes * factor;
2891 spin_unlock(&cache->lock);
2892 spin_unlock(&cache->space_info->lock);
2893
2894 percpu_counter_add_batch(
2895 &cache->space_info->total_bytes_pinned,
2896 num_bytes,
2897 BTRFS_TOTAL_BYTES_PINNED_BATCH);
2898 set_extent_dirty(&trans->transaction->pinned_extents,
2899 bytenr, bytenr + num_bytes - 1,
2900 GFP_NOFS | __GFP_NOFAIL);
2901 }
2902
2903 spin_lock(&trans->transaction->dirty_bgs_lock);
2904 if (list_empty(&cache->dirty_list)) {
2905 list_add_tail(&cache->dirty_list,
2906 &trans->transaction->dirty_bgs);
2907 trans->delayed_ref_updates++;
2908 btrfs_get_block_group(cache);
2909 }
2910 spin_unlock(&trans->transaction->dirty_bgs_lock);
2911
2912 /*
2913 * No longer have used bytes in this block group, queue it for
2914 * deletion. We do this after adding the block group to the
2915 * dirty list to avoid races between cleaner kthread and space
2916 * cache writeout.
2917 */
2918 if (!alloc && old_val == 0) {
2919 if (!btrfs_test_opt(info, DISCARD_ASYNC))
2920 btrfs_mark_bg_unused(cache);
2921 }
2922
2923 btrfs_put_block_group(cache);
2924 total -= num_bytes;
2925 bytenr += num_bytes;
2926 }
2927
2928 /* Modified block groups are accounted for in the delayed_refs_rsv. */
2929 btrfs_update_delayed_refs_rsv(trans);
2930 return ret;
2931}
2932
2933/**
2934 * btrfs_add_reserved_bytes - update the block_group and space info counters
2935 * @cache: The cache we are manipulating
2936 * @ram_bytes: The number of bytes of file content, and will be same to
2937 * @num_bytes except for the compress path.
2938 * @num_bytes: The number of bytes in question
2939 * @delalloc: The blocks are allocated for the delalloc write
2940 *
2941 * This is called by the allocator when it reserves space. If this is a
2942 * reservation and the block group has become read only we cannot make the
2943 * reservation and return -EAGAIN, otherwise this function always succeeds.
2944 */
2945int btrfs_add_reserved_bytes(struct btrfs_block_group *cache,
2946 u64 ram_bytes, u64 num_bytes, int delalloc)
2947{
2948 struct btrfs_space_info *space_info = cache->space_info;
2949 int ret = 0;
2950
2951 spin_lock(&space_info->lock);
2952 spin_lock(&cache->lock);
2953 if (cache->ro) {
2954 ret = -EAGAIN;
2955 } else {
2956 cache->reserved += num_bytes;
2957 space_info->bytes_reserved += num_bytes;
2958 trace_btrfs_space_reservation(cache->fs_info, "space_info",
2959 space_info->flags, num_bytes, 1);
2960 btrfs_space_info_update_bytes_may_use(cache->fs_info,
2961 space_info, -ram_bytes);
2962 if (delalloc)
2963 cache->delalloc_bytes += num_bytes;
2964 }
2965 spin_unlock(&cache->lock);
2966 spin_unlock(&space_info->lock);
2967 return ret;
2968}
2969
2970/**
2971 * btrfs_free_reserved_bytes - update the block_group and space info counters
2972 * @cache: The cache we are manipulating
2973 * @num_bytes: The number of bytes in question
2974 * @delalloc: The blocks are allocated for the delalloc write
2975 *
2976 * This is called by somebody who is freeing space that was never actually used
2977 * on disk. For example if you reserve some space for a new leaf in transaction
2978 * A and before transaction A commits you free that leaf, you call this with
2979 * reserve set to 0 in order to clear the reservation.
2980 */
2981void btrfs_free_reserved_bytes(struct btrfs_block_group *cache,
2982 u64 num_bytes, int delalloc)
2983{
2984 struct btrfs_space_info *space_info = cache->space_info;
2985
2986 spin_lock(&space_info->lock);
2987 spin_lock(&cache->lock);
2988 if (cache->ro)
2989 space_info->bytes_readonly += num_bytes;
2990 cache->reserved -= num_bytes;
2991 space_info->bytes_reserved -= num_bytes;
2992 space_info->max_extent_size = 0;
2993
2994 if (delalloc)
2995 cache->delalloc_bytes -= num_bytes;
2996 spin_unlock(&cache->lock);
2997 spin_unlock(&space_info->lock);
2998}
2999
3000static void force_metadata_allocation(struct btrfs_fs_info *info)
3001{
3002 struct list_head *head = &info->space_info;
3003 struct btrfs_space_info *found;
3004
3005 rcu_read_lock();
3006 list_for_each_entry_rcu(found, head, list) {
3007 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3008 found->force_alloc = CHUNK_ALLOC_FORCE;
3009 }
3010 rcu_read_unlock();
3011}
3012
3013static int should_alloc_chunk(struct btrfs_fs_info *fs_info,
3014 struct btrfs_space_info *sinfo, int force)
3015{
3016 u64 bytes_used = btrfs_space_info_used(sinfo, false);
3017 u64 thresh;
3018
3019 if (force == CHUNK_ALLOC_FORCE)
3020 return 1;
3021
3022 /*
3023 * in limited mode, we want to have some free space up to
3024 * about 1% of the FS size.
3025 */
3026 if (force == CHUNK_ALLOC_LIMITED) {
3027 thresh = btrfs_super_total_bytes(fs_info->super_copy);
3028 thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
3029
3030 if (sinfo->total_bytes - bytes_used < thresh)
3031 return 1;
3032 }
3033
3034 if (bytes_used + SZ_2M < div_factor(sinfo->total_bytes, 8))
3035 return 0;
3036 return 1;
3037}
3038
3039int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans, u64 type)
3040{
3041 u64 alloc_flags = btrfs_get_alloc_profile(trans->fs_info, type);
3042
3043 return btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
3044}
3045
3046/*
3047 * If force is CHUNK_ALLOC_FORCE:
3048 * - return 1 if it successfully allocates a chunk,
3049 * - return errors including -ENOSPC otherwise.
3050 * If force is NOT CHUNK_ALLOC_FORCE:
3051 * - return 0 if it doesn't need to allocate a new chunk,
3052 * - return 1 if it successfully allocates a chunk,
3053 * - return errors including -ENOSPC otherwise.
3054 */
3055int btrfs_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags,
3056 enum btrfs_chunk_alloc_enum force)
3057{
3058 struct btrfs_fs_info *fs_info = trans->fs_info;
3059 struct btrfs_space_info *space_info;
3060 bool wait_for_alloc = false;
3061 bool should_alloc = false;
3062 int ret = 0;
3063
3064 /* Don't re-enter if we're already allocating a chunk */
3065 if (trans->allocating_chunk)
3066 return -ENOSPC;
3067
3068 space_info = btrfs_find_space_info(fs_info, flags);
3069 ASSERT(space_info);
3070
3071 do {
3072 spin_lock(&space_info->lock);
3073 if (force < space_info->force_alloc)
3074 force = space_info->force_alloc;
3075 should_alloc = should_alloc_chunk(fs_info, space_info, force);
3076 if (space_info->full) {
3077 /* No more free physical space */
3078 if (should_alloc)
3079 ret = -ENOSPC;
3080 else
3081 ret = 0;
3082 spin_unlock(&space_info->lock);
3083 return ret;
3084 } else if (!should_alloc) {
3085 spin_unlock(&space_info->lock);
3086 return 0;
3087 } else if (space_info->chunk_alloc) {
3088 /*
3089 * Someone is already allocating, so we need to block
3090 * until this someone is finished and then loop to
3091 * recheck if we should continue with our allocation
3092 * attempt.
3093 */
3094 wait_for_alloc = true;
3095 spin_unlock(&space_info->lock);
3096 mutex_lock(&fs_info->chunk_mutex);
3097 mutex_unlock(&fs_info->chunk_mutex);
3098 } else {
3099 /* Proceed with allocation */
3100 space_info->chunk_alloc = 1;
3101 wait_for_alloc = false;
3102 spin_unlock(&space_info->lock);
3103 }
3104
3105 cond_resched();
3106 } while (wait_for_alloc);
3107
3108 mutex_lock(&fs_info->chunk_mutex);
3109 trans->allocating_chunk = true;
3110
3111 /*
3112 * If we have mixed data/metadata chunks we want to make sure we keep
3113 * allocating mixed chunks instead of individual chunks.
3114 */
3115 if (btrfs_mixed_space_info(space_info))
3116 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3117
3118 /*
3119 * if we're doing a data chunk, go ahead and make sure that
3120 * we keep a reasonable number of metadata chunks allocated in the
3121 * FS as well.
3122 */
3123 if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3124 fs_info->data_chunk_allocations++;
3125 if (!(fs_info->data_chunk_allocations %
3126 fs_info->metadata_ratio))
3127 force_metadata_allocation(fs_info);
3128 }
3129
3130 /*
3131 * Check if we have enough space in SYSTEM chunk because we may need
3132 * to update devices.
3133 */
3134 check_system_chunk(trans, flags);
3135
3136 ret = btrfs_alloc_chunk(trans, flags);
3137 trans->allocating_chunk = false;
3138
3139 spin_lock(&space_info->lock);
3140 if (ret < 0) {
3141 if (ret == -ENOSPC)
3142 space_info->full = 1;
3143 else
3144 goto out;
3145 } else {
3146 ret = 1;
3147 space_info->max_extent_size = 0;
3148 }
3149
3150 space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3151out:
3152 space_info->chunk_alloc = 0;
3153 spin_unlock(&space_info->lock);
3154 mutex_unlock(&fs_info->chunk_mutex);
3155 /*
3156 * When we allocate a new chunk we reserve space in the chunk block
3157 * reserve to make sure we can COW nodes/leafs in the chunk tree or
3158 * add new nodes/leafs to it if we end up needing to do it when
3159 * inserting the chunk item and updating device items as part of the
3160 * second phase of chunk allocation, performed by
3161 * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
3162 * large number of new block groups to create in our transaction
3163 * handle's new_bgs list to avoid exhausting the chunk block reserve
3164 * in extreme cases - like having a single transaction create many new
3165 * block groups when starting to write out the free space caches of all
3166 * the block groups that were made dirty during the lifetime of the
3167 * transaction.
3168 */
3169 if (trans->chunk_bytes_reserved >= (u64)SZ_2M)
3170 btrfs_create_pending_block_groups(trans);
3171
3172 return ret;
3173}
3174
3175static u64 get_profile_num_devs(struct btrfs_fs_info *fs_info, u64 type)
3176{
3177 u64 num_dev;
3178
3179 num_dev = btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)].devs_max;
3180 if (!num_dev)
3181 num_dev = fs_info->fs_devices->rw_devices;
3182
3183 return num_dev;
3184}
3185
3186/*
3187 * Reserve space in the system space for allocating or removing a chunk
3188 */
3189void check_system_chunk(struct btrfs_trans_handle *trans, u64 type)
3190{
3191 struct btrfs_fs_info *fs_info = trans->fs_info;
3192 struct btrfs_space_info *info;
3193 u64 left;
3194 u64 thresh;
3195 int ret = 0;
3196 u64 num_devs;
3197
3198 /*
3199 * Needed because we can end up allocating a system chunk and for an
3200 * atomic and race free space reservation in the chunk block reserve.
3201 */
3202 lockdep_assert_held(&fs_info->chunk_mutex);
3203
3204 info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
3205 spin_lock(&info->lock);
3206 left = info->total_bytes - btrfs_space_info_used(info, true);
3207 spin_unlock(&info->lock);
3208
3209 num_devs = get_profile_num_devs(fs_info, type);
3210
3211 /* num_devs device items to update and 1 chunk item to add or remove */
3212 thresh = btrfs_calc_metadata_size(fs_info, num_devs) +
3213 btrfs_calc_insert_metadata_size(fs_info, 1);
3214
3215 if (left < thresh && btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
3216 btrfs_info(fs_info, "left=%llu, need=%llu, flags=%llu",
3217 left, thresh, type);
3218 btrfs_dump_space_info(fs_info, info, 0, 0);
3219 }
3220
3221 if (left < thresh) {
3222 u64 flags = btrfs_system_alloc_profile(fs_info);
3223
3224 /*
3225 * Ignore failure to create system chunk. We might end up not
3226 * needing it, as we might not need to COW all nodes/leafs from
3227 * the paths we visit in the chunk tree (they were already COWed
3228 * or created in the current transaction for example).
3229 */
3230 ret = btrfs_alloc_chunk(trans, flags);
3231 }
3232
3233 if (!ret) {
3234 ret = btrfs_block_rsv_add(fs_info->chunk_root,
3235 &fs_info->chunk_block_rsv,
3236 thresh, BTRFS_RESERVE_NO_FLUSH);
3237 if (!ret)
3238 trans->chunk_bytes_reserved += thresh;
3239 }
3240}
3241
3242void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
3243{
3244 struct btrfs_block_group *block_group;
3245 u64 last = 0;
3246
3247 while (1) {
3248 struct inode *inode;
3249
3250 block_group = btrfs_lookup_first_block_group(info, last);
3251 while (block_group) {
3252 btrfs_wait_block_group_cache_done(block_group);
3253 spin_lock(&block_group->lock);
3254 if (block_group->iref)
3255 break;
3256 spin_unlock(&block_group->lock);
3257 block_group = btrfs_next_block_group(block_group);
3258 }
3259 if (!block_group) {
3260 if (last == 0)
3261 break;
3262 last = 0;
3263 continue;
3264 }
3265
3266 inode = block_group->inode;
3267 block_group->iref = 0;
3268 block_group->inode = NULL;
3269 spin_unlock(&block_group->lock);
3270 ASSERT(block_group->io_ctl.inode == NULL);
3271 iput(inode);
3272 last = block_group->start + block_group->length;
3273 btrfs_put_block_group(block_group);
3274 }
3275}
3276
3277/*
3278 * Must be called only after stopping all workers, since we could have block
3279 * group caching kthreads running, and therefore they could race with us if we
3280 * freed the block groups before stopping them.
3281 */
3282int btrfs_free_block_groups(struct btrfs_fs_info *info)
3283{
3284 struct btrfs_block_group *block_group;
3285 struct btrfs_space_info *space_info;
3286 struct btrfs_caching_control *caching_ctl;
3287 struct rb_node *n;
3288
3289 down_write(&info->commit_root_sem);
3290 while (!list_empty(&info->caching_block_groups)) {
3291 caching_ctl = list_entry(info->caching_block_groups.next,
3292 struct btrfs_caching_control, list);
3293 list_del(&caching_ctl->list);
3294 btrfs_put_caching_control(caching_ctl);
3295 }
3296 up_write(&info->commit_root_sem);
3297
3298 spin_lock(&info->unused_bgs_lock);
3299 while (!list_empty(&info->unused_bgs)) {
3300 block_group = list_first_entry(&info->unused_bgs,
3301 struct btrfs_block_group,
3302 bg_list);
3303 list_del_init(&block_group->bg_list);
3304 btrfs_put_block_group(block_group);
3305 }
3306 spin_unlock(&info->unused_bgs_lock);
3307
3308 spin_lock(&info->block_group_cache_lock);
3309 while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
3310 block_group = rb_entry(n, struct btrfs_block_group,
3311 cache_node);
3312 rb_erase(&block_group->cache_node,
3313 &info->block_group_cache_tree);
3314 RB_CLEAR_NODE(&block_group->cache_node);
3315 spin_unlock(&info->block_group_cache_lock);
3316
3317 down_write(&block_group->space_info->groups_sem);
3318 list_del(&block_group->list);
3319 up_write(&block_group->space_info->groups_sem);
3320
3321 /*
3322 * We haven't cached this block group, which means we could
3323 * possibly have excluded extents on this block group.
3324 */
3325 if (block_group->cached == BTRFS_CACHE_NO ||
3326 block_group->cached == BTRFS_CACHE_ERROR)
3327 btrfs_free_excluded_extents(block_group);
3328
3329 btrfs_remove_free_space_cache(block_group);
3330 ASSERT(block_group->cached != BTRFS_CACHE_STARTED);
3331 ASSERT(list_empty(&block_group->dirty_list));
3332 ASSERT(list_empty(&block_group->io_list));
3333 ASSERT(list_empty(&block_group->bg_list));
3334 ASSERT(refcount_read(&block_group->refs) == 1);
3335 btrfs_put_block_group(block_group);
3336
3337 spin_lock(&info->block_group_cache_lock);
3338 }
3339 spin_unlock(&info->block_group_cache_lock);
3340
3341 /*
3342 * Now that all the block groups are freed, go through and free all the
3343 * space_info structs. This is only called during the final stages of
3344 * unmount, and so we know nobody is using them. We call
3345 * synchronize_rcu() once before we start, just to be on the safe side.
3346 */
3347 synchronize_rcu();
3348
3349 btrfs_release_global_block_rsv(info);
3350
3351 while (!list_empty(&info->space_info)) {
3352 space_info = list_entry(info->space_info.next,
3353 struct btrfs_space_info,
3354 list);
3355
3356 /*
3357 * Do not hide this behind enospc_debug, this is actually
3358 * important and indicates a real bug if this happens.
3359 */
3360 if (WARN_ON(space_info->bytes_pinned > 0 ||
3361 space_info->bytes_reserved > 0 ||
3362 space_info->bytes_may_use > 0))
3363 btrfs_dump_space_info(info, space_info, 0, 0);
3364 WARN_ON(space_info->reclaim_size > 0);
3365 list_del(&space_info->list);
3366 btrfs_sysfs_remove_space_info(space_info);
3367 }
3368 return 0;
3369}
3370
3371void btrfs_freeze_block_group(struct btrfs_block_group *cache)
3372{
3373 atomic_inc(&cache->frozen);
3374}
3375
3376void btrfs_unfreeze_block_group(struct btrfs_block_group *block_group)
3377{
3378 struct btrfs_fs_info *fs_info = block_group->fs_info;
3379 struct extent_map_tree *em_tree;
3380 struct extent_map *em;
3381 bool cleanup;
3382
3383 spin_lock(&block_group->lock);
3384 cleanup = (atomic_dec_and_test(&block_group->frozen) &&
3385 block_group->removed);
3386 spin_unlock(&block_group->lock);
3387
3388 if (cleanup) {
3389 em_tree = &fs_info->mapping_tree;
3390 write_lock(&em_tree->lock);
3391 em = lookup_extent_mapping(em_tree, block_group->start,
3392 1);
3393 BUG_ON(!em); /* logic error, can't happen */
3394 remove_extent_mapping(em_tree, em);
3395 write_unlock(&em_tree->lock);
3396
3397 /* once for us and once for the tree */
3398 free_extent_map(em);
3399 free_extent_map(em);
3400
3401 /*
3402 * We may have left one free space entry and other possible
3403 * tasks trimming this block group have left 1 entry each one.
3404 * Free them if any.
3405 */
3406 __btrfs_remove_free_space_cache(block_group->free_space_ctl);
3407 }
3408}