Loading...
1// SPDX-License-Identifier: GPL-2.0
2
3#include <linux/sizes.h>
4#include <linux/list_sort.h>
5#include "misc.h"
6#include "ctree.h"
7#include "block-group.h"
8#include "space-info.h"
9#include "disk-io.h"
10#include "free-space-cache.h"
11#include "free-space-tree.h"
12#include "volumes.h"
13#include "transaction.h"
14#include "ref-verify.h"
15#include "sysfs.h"
16#include "tree-log.h"
17#include "delalloc-space.h"
18#include "discard.h"
19#include "raid56.h"
20#include "zoned.h"
21#include "fs.h"
22#include "accessors.h"
23#include "extent-tree.h"
24
25#ifdef CONFIG_BTRFS_DEBUG
26int btrfs_should_fragment_free_space(struct btrfs_block_group *block_group)
27{
28 struct btrfs_fs_info *fs_info = block_group->fs_info;
29
30 return (btrfs_test_opt(fs_info, FRAGMENT_METADATA) &&
31 block_group->flags & BTRFS_BLOCK_GROUP_METADATA) ||
32 (btrfs_test_opt(fs_info, FRAGMENT_DATA) &&
33 block_group->flags & BTRFS_BLOCK_GROUP_DATA);
34}
35#endif
36
37/*
38 * Return target flags in extended format or 0 if restripe for this chunk_type
39 * is not in progress
40 *
41 * Should be called with balance_lock held
42 */
43static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
44{
45 struct btrfs_balance_control *bctl = fs_info->balance_ctl;
46 u64 target = 0;
47
48 if (!bctl)
49 return 0;
50
51 if (flags & BTRFS_BLOCK_GROUP_DATA &&
52 bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
53 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
54 } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
55 bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
56 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
57 } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
58 bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
59 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
60 }
61
62 return target;
63}
64
65/*
66 * @flags: available profiles in extended format (see ctree.h)
67 *
68 * Return reduced profile in chunk format. If profile changing is in progress
69 * (either running or paused) picks the target profile (if it's already
70 * available), otherwise falls back to plain reducing.
71 */
72static u64 btrfs_reduce_alloc_profile(struct btrfs_fs_info *fs_info, u64 flags)
73{
74 u64 num_devices = fs_info->fs_devices->rw_devices;
75 u64 target;
76 u64 raid_type;
77 u64 allowed = 0;
78
79 /*
80 * See if restripe for this chunk_type is in progress, if so try to
81 * reduce to the target profile
82 */
83 spin_lock(&fs_info->balance_lock);
84 target = get_restripe_target(fs_info, flags);
85 if (target) {
86 spin_unlock(&fs_info->balance_lock);
87 return extended_to_chunk(target);
88 }
89 spin_unlock(&fs_info->balance_lock);
90
91 /* First, mask out the RAID levels which aren't possible */
92 for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
93 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
94 allowed |= btrfs_raid_array[raid_type].bg_flag;
95 }
96 allowed &= flags;
97
98 /* Select the highest-redundancy RAID level. */
99 if (allowed & BTRFS_BLOCK_GROUP_RAID1C4)
100 allowed = BTRFS_BLOCK_GROUP_RAID1C4;
101 else if (allowed & BTRFS_BLOCK_GROUP_RAID6)
102 allowed = BTRFS_BLOCK_GROUP_RAID6;
103 else if (allowed & BTRFS_BLOCK_GROUP_RAID1C3)
104 allowed = BTRFS_BLOCK_GROUP_RAID1C3;
105 else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
106 allowed = BTRFS_BLOCK_GROUP_RAID5;
107 else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
108 allowed = BTRFS_BLOCK_GROUP_RAID10;
109 else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
110 allowed = BTRFS_BLOCK_GROUP_RAID1;
111 else if (allowed & BTRFS_BLOCK_GROUP_DUP)
112 allowed = BTRFS_BLOCK_GROUP_DUP;
113 else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
114 allowed = BTRFS_BLOCK_GROUP_RAID0;
115
116 flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
117
118 return extended_to_chunk(flags | allowed);
119}
120
121u64 btrfs_get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags)
122{
123 unsigned seq;
124 u64 flags;
125
126 do {
127 flags = orig_flags;
128 seq = read_seqbegin(&fs_info->profiles_lock);
129
130 if (flags & BTRFS_BLOCK_GROUP_DATA)
131 flags |= fs_info->avail_data_alloc_bits;
132 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
133 flags |= fs_info->avail_system_alloc_bits;
134 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
135 flags |= fs_info->avail_metadata_alloc_bits;
136 } while (read_seqretry(&fs_info->profiles_lock, seq));
137
138 return btrfs_reduce_alloc_profile(fs_info, flags);
139}
140
141void btrfs_get_block_group(struct btrfs_block_group *cache)
142{
143 refcount_inc(&cache->refs);
144}
145
146void btrfs_put_block_group(struct btrfs_block_group *cache)
147{
148 if (refcount_dec_and_test(&cache->refs)) {
149 WARN_ON(cache->pinned > 0);
150 /*
151 * If there was a failure to cleanup a log tree, very likely due
152 * to an IO failure on a writeback attempt of one or more of its
153 * extent buffers, we could not do proper (and cheap) unaccounting
154 * of their reserved space, so don't warn on reserved > 0 in that
155 * case.
156 */
157 if (!(cache->flags & BTRFS_BLOCK_GROUP_METADATA) ||
158 !BTRFS_FS_LOG_CLEANUP_ERROR(cache->fs_info))
159 WARN_ON(cache->reserved > 0);
160
161 /*
162 * A block_group shouldn't be on the discard_list anymore.
163 * Remove the block_group from the discard_list to prevent us
164 * from causing a panic due to NULL pointer dereference.
165 */
166 if (WARN_ON(!list_empty(&cache->discard_list)))
167 btrfs_discard_cancel_work(&cache->fs_info->discard_ctl,
168 cache);
169
170 kfree(cache->free_space_ctl);
171 btrfs_free_chunk_map(cache->physical_map);
172 kfree(cache);
173 }
174}
175
176/*
177 * This adds the block group to the fs_info rb tree for the block group cache
178 */
179static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
180 struct btrfs_block_group *block_group)
181{
182 struct rb_node **p;
183 struct rb_node *parent = NULL;
184 struct btrfs_block_group *cache;
185 bool leftmost = true;
186
187 ASSERT(block_group->length != 0);
188
189 write_lock(&info->block_group_cache_lock);
190 p = &info->block_group_cache_tree.rb_root.rb_node;
191
192 while (*p) {
193 parent = *p;
194 cache = rb_entry(parent, struct btrfs_block_group, cache_node);
195 if (block_group->start < cache->start) {
196 p = &(*p)->rb_left;
197 } else if (block_group->start > cache->start) {
198 p = &(*p)->rb_right;
199 leftmost = false;
200 } else {
201 write_unlock(&info->block_group_cache_lock);
202 return -EEXIST;
203 }
204 }
205
206 rb_link_node(&block_group->cache_node, parent, p);
207 rb_insert_color_cached(&block_group->cache_node,
208 &info->block_group_cache_tree, leftmost);
209
210 write_unlock(&info->block_group_cache_lock);
211
212 return 0;
213}
214
215/*
216 * This will return the block group at or after bytenr if contains is 0, else
217 * it will return the block group that contains the bytenr
218 */
219static struct btrfs_block_group *block_group_cache_tree_search(
220 struct btrfs_fs_info *info, u64 bytenr, int contains)
221{
222 struct btrfs_block_group *cache, *ret = NULL;
223 struct rb_node *n;
224 u64 end, start;
225
226 read_lock(&info->block_group_cache_lock);
227 n = info->block_group_cache_tree.rb_root.rb_node;
228
229 while (n) {
230 cache = rb_entry(n, struct btrfs_block_group, cache_node);
231 end = cache->start + cache->length - 1;
232 start = cache->start;
233
234 if (bytenr < start) {
235 if (!contains && (!ret || start < ret->start))
236 ret = cache;
237 n = n->rb_left;
238 } else if (bytenr > start) {
239 if (contains && bytenr <= end) {
240 ret = cache;
241 break;
242 }
243 n = n->rb_right;
244 } else {
245 ret = cache;
246 break;
247 }
248 }
249 if (ret)
250 btrfs_get_block_group(ret);
251 read_unlock(&info->block_group_cache_lock);
252
253 return ret;
254}
255
256/*
257 * Return the block group that starts at or after bytenr
258 */
259struct btrfs_block_group *btrfs_lookup_first_block_group(
260 struct btrfs_fs_info *info, u64 bytenr)
261{
262 return block_group_cache_tree_search(info, bytenr, 0);
263}
264
265/*
266 * Return the block group that contains the given bytenr
267 */
268struct btrfs_block_group *btrfs_lookup_block_group(
269 struct btrfs_fs_info *info, u64 bytenr)
270{
271 return block_group_cache_tree_search(info, bytenr, 1);
272}
273
274struct btrfs_block_group *btrfs_next_block_group(
275 struct btrfs_block_group *cache)
276{
277 struct btrfs_fs_info *fs_info = cache->fs_info;
278 struct rb_node *node;
279
280 read_lock(&fs_info->block_group_cache_lock);
281
282 /* If our block group was removed, we need a full search. */
283 if (RB_EMPTY_NODE(&cache->cache_node)) {
284 const u64 next_bytenr = cache->start + cache->length;
285
286 read_unlock(&fs_info->block_group_cache_lock);
287 btrfs_put_block_group(cache);
288 return btrfs_lookup_first_block_group(fs_info, next_bytenr);
289 }
290 node = rb_next(&cache->cache_node);
291 btrfs_put_block_group(cache);
292 if (node) {
293 cache = rb_entry(node, struct btrfs_block_group, cache_node);
294 btrfs_get_block_group(cache);
295 } else
296 cache = NULL;
297 read_unlock(&fs_info->block_group_cache_lock);
298 return cache;
299}
300
301/*
302 * Check if we can do a NOCOW write for a given extent.
303 *
304 * @fs_info: The filesystem information object.
305 * @bytenr: Logical start address of the extent.
306 *
307 * Check if we can do a NOCOW write for the given extent, and increments the
308 * number of NOCOW writers in the block group that contains the extent, as long
309 * as the block group exists and it's currently not in read-only mode.
310 *
311 * Returns: A non-NULL block group pointer if we can do a NOCOW write, the caller
312 * is responsible for calling btrfs_dec_nocow_writers() later.
313 *
314 * Or NULL if we can not do a NOCOW write
315 */
316struct btrfs_block_group *btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info,
317 u64 bytenr)
318{
319 struct btrfs_block_group *bg;
320 bool can_nocow = true;
321
322 bg = btrfs_lookup_block_group(fs_info, bytenr);
323 if (!bg)
324 return NULL;
325
326 spin_lock(&bg->lock);
327 if (bg->ro)
328 can_nocow = false;
329 else
330 atomic_inc(&bg->nocow_writers);
331 spin_unlock(&bg->lock);
332
333 if (!can_nocow) {
334 btrfs_put_block_group(bg);
335 return NULL;
336 }
337
338 /* No put on block group, done by btrfs_dec_nocow_writers(). */
339 return bg;
340}
341
342/*
343 * Decrement the number of NOCOW writers in a block group.
344 *
345 * This is meant to be called after a previous call to btrfs_inc_nocow_writers(),
346 * and on the block group returned by that call. Typically this is called after
347 * creating an ordered extent for a NOCOW write, to prevent races with scrub and
348 * relocation.
349 *
350 * After this call, the caller should not use the block group anymore. It it wants
351 * to use it, then it should get a reference on it before calling this function.
352 */
353void btrfs_dec_nocow_writers(struct btrfs_block_group *bg)
354{
355 if (atomic_dec_and_test(&bg->nocow_writers))
356 wake_up_var(&bg->nocow_writers);
357
358 /* For the lookup done by a previous call to btrfs_inc_nocow_writers(). */
359 btrfs_put_block_group(bg);
360}
361
362void btrfs_wait_nocow_writers(struct btrfs_block_group *bg)
363{
364 wait_var_event(&bg->nocow_writers, !atomic_read(&bg->nocow_writers));
365}
366
367void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
368 const u64 start)
369{
370 struct btrfs_block_group *bg;
371
372 bg = btrfs_lookup_block_group(fs_info, start);
373 ASSERT(bg);
374 if (atomic_dec_and_test(&bg->reservations))
375 wake_up_var(&bg->reservations);
376 btrfs_put_block_group(bg);
377}
378
379void btrfs_wait_block_group_reservations(struct btrfs_block_group *bg)
380{
381 struct btrfs_space_info *space_info = bg->space_info;
382
383 ASSERT(bg->ro);
384
385 if (!(bg->flags & BTRFS_BLOCK_GROUP_DATA))
386 return;
387
388 /*
389 * Our block group is read only but before we set it to read only,
390 * some task might have had allocated an extent from it already, but it
391 * has not yet created a respective ordered extent (and added it to a
392 * root's list of ordered extents).
393 * Therefore wait for any task currently allocating extents, since the
394 * block group's reservations counter is incremented while a read lock
395 * on the groups' semaphore is held and decremented after releasing
396 * the read access on that semaphore and creating the ordered extent.
397 */
398 down_write(&space_info->groups_sem);
399 up_write(&space_info->groups_sem);
400
401 wait_var_event(&bg->reservations, !atomic_read(&bg->reservations));
402}
403
404struct btrfs_caching_control *btrfs_get_caching_control(
405 struct btrfs_block_group *cache)
406{
407 struct btrfs_caching_control *ctl;
408
409 spin_lock(&cache->lock);
410 if (!cache->caching_ctl) {
411 spin_unlock(&cache->lock);
412 return NULL;
413 }
414
415 ctl = cache->caching_ctl;
416 refcount_inc(&ctl->count);
417 spin_unlock(&cache->lock);
418 return ctl;
419}
420
421void btrfs_put_caching_control(struct btrfs_caching_control *ctl)
422{
423 if (refcount_dec_and_test(&ctl->count))
424 kfree(ctl);
425}
426
427/*
428 * When we wait for progress in the block group caching, its because our
429 * allocation attempt failed at least once. So, we must sleep and let some
430 * progress happen before we try again.
431 *
432 * This function will sleep at least once waiting for new free space to show
433 * up, and then it will check the block group free space numbers for our min
434 * num_bytes. Another option is to have it go ahead and look in the rbtree for
435 * a free extent of a given size, but this is a good start.
436 *
437 * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
438 * any of the information in this block group.
439 */
440void btrfs_wait_block_group_cache_progress(struct btrfs_block_group *cache,
441 u64 num_bytes)
442{
443 struct btrfs_caching_control *caching_ctl;
444 int progress;
445
446 caching_ctl = btrfs_get_caching_control(cache);
447 if (!caching_ctl)
448 return;
449
450 /*
451 * We've already failed to allocate from this block group, so even if
452 * there's enough space in the block group it isn't contiguous enough to
453 * allow for an allocation, so wait for at least the next wakeup tick,
454 * or for the thing to be done.
455 */
456 progress = atomic_read(&caching_ctl->progress);
457
458 wait_event(caching_ctl->wait, btrfs_block_group_done(cache) ||
459 (progress != atomic_read(&caching_ctl->progress) &&
460 (cache->free_space_ctl->free_space >= num_bytes)));
461
462 btrfs_put_caching_control(caching_ctl);
463}
464
465static int btrfs_caching_ctl_wait_done(struct btrfs_block_group *cache,
466 struct btrfs_caching_control *caching_ctl)
467{
468 wait_event(caching_ctl->wait, btrfs_block_group_done(cache));
469 return cache->cached == BTRFS_CACHE_ERROR ? -EIO : 0;
470}
471
472static int btrfs_wait_block_group_cache_done(struct btrfs_block_group *cache)
473{
474 struct btrfs_caching_control *caching_ctl;
475 int ret;
476
477 caching_ctl = btrfs_get_caching_control(cache);
478 if (!caching_ctl)
479 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
480 ret = btrfs_caching_ctl_wait_done(cache, caching_ctl);
481 btrfs_put_caching_control(caching_ctl);
482 return ret;
483}
484
485#ifdef CONFIG_BTRFS_DEBUG
486static void fragment_free_space(struct btrfs_block_group *block_group)
487{
488 struct btrfs_fs_info *fs_info = block_group->fs_info;
489 u64 start = block_group->start;
490 u64 len = block_group->length;
491 u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ?
492 fs_info->nodesize : fs_info->sectorsize;
493 u64 step = chunk << 1;
494
495 while (len > chunk) {
496 btrfs_remove_free_space(block_group, start, chunk);
497 start += step;
498 if (len < step)
499 len = 0;
500 else
501 len -= step;
502 }
503}
504#endif
505
506/*
507 * Add a free space range to the in memory free space cache of a block group.
508 * This checks if the range contains super block locations and any such
509 * locations are not added to the free space cache.
510 *
511 * @block_group: The target block group.
512 * @start: Start offset of the range.
513 * @end: End offset of the range (exclusive).
514 * @total_added_ret: Optional pointer to return the total amount of space
515 * added to the block group's free space cache.
516 *
517 * Returns 0 on success or < 0 on error.
518 */
519int btrfs_add_new_free_space(struct btrfs_block_group *block_group, u64 start,
520 u64 end, u64 *total_added_ret)
521{
522 struct btrfs_fs_info *info = block_group->fs_info;
523 u64 extent_start, extent_end, size;
524 int ret;
525
526 if (total_added_ret)
527 *total_added_ret = 0;
528
529 while (start < end) {
530 if (!find_first_extent_bit(&info->excluded_extents, start,
531 &extent_start, &extent_end,
532 EXTENT_DIRTY | EXTENT_UPTODATE,
533 NULL))
534 break;
535
536 if (extent_start <= start) {
537 start = extent_end + 1;
538 } else if (extent_start > start && extent_start < end) {
539 size = extent_start - start;
540 ret = btrfs_add_free_space_async_trimmed(block_group,
541 start, size);
542 if (ret)
543 return ret;
544 if (total_added_ret)
545 *total_added_ret += size;
546 start = extent_end + 1;
547 } else {
548 break;
549 }
550 }
551
552 if (start < end) {
553 size = end - start;
554 ret = btrfs_add_free_space_async_trimmed(block_group, start,
555 size);
556 if (ret)
557 return ret;
558 if (total_added_ret)
559 *total_added_ret += size;
560 }
561
562 return 0;
563}
564
565/*
566 * Get an arbitrary extent item index / max_index through the block group
567 *
568 * @block_group the block group to sample from
569 * @index: the integral step through the block group to grab from
570 * @max_index: the granularity of the sampling
571 * @key: return value parameter for the item we find
572 *
573 * Pre-conditions on indices:
574 * 0 <= index <= max_index
575 * 0 < max_index
576 *
577 * Returns: 0 on success, 1 if the search didn't yield a useful item, negative
578 * error code on error.
579 */
580static int sample_block_group_extent_item(struct btrfs_caching_control *caching_ctl,
581 struct btrfs_block_group *block_group,
582 int index, int max_index,
583 struct btrfs_key *found_key)
584{
585 struct btrfs_fs_info *fs_info = block_group->fs_info;
586 struct btrfs_root *extent_root;
587 u64 search_offset;
588 u64 search_end = block_group->start + block_group->length;
589 struct btrfs_path *path;
590 struct btrfs_key search_key;
591 int ret = 0;
592
593 ASSERT(index >= 0);
594 ASSERT(index <= max_index);
595 ASSERT(max_index > 0);
596 lockdep_assert_held(&caching_ctl->mutex);
597 lockdep_assert_held_read(&fs_info->commit_root_sem);
598
599 path = btrfs_alloc_path();
600 if (!path)
601 return -ENOMEM;
602
603 extent_root = btrfs_extent_root(fs_info, max_t(u64, block_group->start,
604 BTRFS_SUPER_INFO_OFFSET));
605
606 path->skip_locking = 1;
607 path->search_commit_root = 1;
608 path->reada = READA_FORWARD;
609
610 search_offset = index * div_u64(block_group->length, max_index);
611 search_key.objectid = block_group->start + search_offset;
612 search_key.type = BTRFS_EXTENT_ITEM_KEY;
613 search_key.offset = 0;
614
615 btrfs_for_each_slot(extent_root, &search_key, found_key, path, ret) {
616 /* Success; sampled an extent item in the block group */
617 if (found_key->type == BTRFS_EXTENT_ITEM_KEY &&
618 found_key->objectid >= block_group->start &&
619 found_key->objectid + found_key->offset <= search_end)
620 break;
621
622 /* We can't possibly find a valid extent item anymore */
623 if (found_key->objectid >= search_end) {
624 ret = 1;
625 break;
626 }
627 }
628
629 lockdep_assert_held(&caching_ctl->mutex);
630 lockdep_assert_held_read(&fs_info->commit_root_sem);
631 btrfs_free_path(path);
632 return ret;
633}
634
635/*
636 * Best effort attempt to compute a block group's size class while caching it.
637 *
638 * @block_group: the block group we are caching
639 *
640 * We cannot infer the size class while adding free space extents, because that
641 * logic doesn't care about contiguous file extents (it doesn't differentiate
642 * between a 100M extent and 100 contiguous 1M extents). So we need to read the
643 * file extent items. Reading all of them is quite wasteful, because usually
644 * only a handful are enough to give a good answer. Therefore, we just grab 5 of
645 * them at even steps through the block group and pick the smallest size class
646 * we see. Since size class is best effort, and not guaranteed in general,
647 * inaccuracy is acceptable.
648 *
649 * To be more explicit about why this algorithm makes sense:
650 *
651 * If we are caching in a block group from disk, then there are three major cases
652 * to consider:
653 * 1. the block group is well behaved and all extents in it are the same size
654 * class.
655 * 2. the block group is mostly one size class with rare exceptions for last
656 * ditch allocations
657 * 3. the block group was populated before size classes and can have a totally
658 * arbitrary mix of size classes.
659 *
660 * In case 1, looking at any extent in the block group will yield the correct
661 * result. For the mixed cases, taking the minimum size class seems like a good
662 * approximation, since gaps from frees will be usable to the size class. For
663 * 2., a small handful of file extents is likely to yield the right answer. For
664 * 3, we can either read every file extent, or admit that this is best effort
665 * anyway and try to stay fast.
666 *
667 * Returns: 0 on success, negative error code on error.
668 */
669static int load_block_group_size_class(struct btrfs_caching_control *caching_ctl,
670 struct btrfs_block_group *block_group)
671{
672 struct btrfs_fs_info *fs_info = block_group->fs_info;
673 struct btrfs_key key;
674 int i;
675 u64 min_size = block_group->length;
676 enum btrfs_block_group_size_class size_class = BTRFS_BG_SZ_NONE;
677 int ret;
678
679 if (!btrfs_block_group_should_use_size_class(block_group))
680 return 0;
681
682 lockdep_assert_held(&caching_ctl->mutex);
683 lockdep_assert_held_read(&fs_info->commit_root_sem);
684 for (i = 0; i < 5; ++i) {
685 ret = sample_block_group_extent_item(caching_ctl, block_group, i, 5, &key);
686 if (ret < 0)
687 goto out;
688 if (ret > 0)
689 continue;
690 min_size = min_t(u64, min_size, key.offset);
691 size_class = btrfs_calc_block_group_size_class(min_size);
692 }
693 if (size_class != BTRFS_BG_SZ_NONE) {
694 spin_lock(&block_group->lock);
695 block_group->size_class = size_class;
696 spin_unlock(&block_group->lock);
697 }
698out:
699 return ret;
700}
701
702static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl)
703{
704 struct btrfs_block_group *block_group = caching_ctl->block_group;
705 struct btrfs_fs_info *fs_info = block_group->fs_info;
706 struct btrfs_root *extent_root;
707 struct btrfs_path *path;
708 struct extent_buffer *leaf;
709 struct btrfs_key key;
710 u64 total_found = 0;
711 u64 last = 0;
712 u32 nritems;
713 int ret;
714 bool wakeup = true;
715
716 path = btrfs_alloc_path();
717 if (!path)
718 return -ENOMEM;
719
720 last = max_t(u64, block_group->start, BTRFS_SUPER_INFO_OFFSET);
721 extent_root = btrfs_extent_root(fs_info, last);
722
723#ifdef CONFIG_BTRFS_DEBUG
724 /*
725 * If we're fragmenting we don't want to make anybody think we can
726 * allocate from this block group until we've had a chance to fragment
727 * the free space.
728 */
729 if (btrfs_should_fragment_free_space(block_group))
730 wakeup = false;
731#endif
732 /*
733 * We don't want to deadlock with somebody trying to allocate a new
734 * extent for the extent root while also trying to search the extent
735 * root to add free space. So we skip locking and search the commit
736 * root, since its read-only
737 */
738 path->skip_locking = 1;
739 path->search_commit_root = 1;
740 path->reada = READA_FORWARD;
741
742 key.objectid = last;
743 key.offset = 0;
744 key.type = BTRFS_EXTENT_ITEM_KEY;
745
746next:
747 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
748 if (ret < 0)
749 goto out;
750
751 leaf = path->nodes[0];
752 nritems = btrfs_header_nritems(leaf);
753
754 while (1) {
755 if (btrfs_fs_closing(fs_info) > 1) {
756 last = (u64)-1;
757 break;
758 }
759
760 if (path->slots[0] < nritems) {
761 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
762 } else {
763 ret = btrfs_find_next_key(extent_root, path, &key, 0, 0);
764 if (ret)
765 break;
766
767 if (need_resched() ||
768 rwsem_is_contended(&fs_info->commit_root_sem)) {
769 btrfs_release_path(path);
770 up_read(&fs_info->commit_root_sem);
771 mutex_unlock(&caching_ctl->mutex);
772 cond_resched();
773 mutex_lock(&caching_ctl->mutex);
774 down_read(&fs_info->commit_root_sem);
775 goto next;
776 }
777
778 ret = btrfs_next_leaf(extent_root, path);
779 if (ret < 0)
780 goto out;
781 if (ret)
782 break;
783 leaf = path->nodes[0];
784 nritems = btrfs_header_nritems(leaf);
785 continue;
786 }
787
788 if (key.objectid < last) {
789 key.objectid = last;
790 key.offset = 0;
791 key.type = BTRFS_EXTENT_ITEM_KEY;
792 btrfs_release_path(path);
793 goto next;
794 }
795
796 if (key.objectid < block_group->start) {
797 path->slots[0]++;
798 continue;
799 }
800
801 if (key.objectid >= block_group->start + block_group->length)
802 break;
803
804 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
805 key.type == BTRFS_METADATA_ITEM_KEY) {
806 u64 space_added;
807
808 ret = btrfs_add_new_free_space(block_group, last,
809 key.objectid, &space_added);
810 if (ret)
811 goto out;
812 total_found += space_added;
813 if (key.type == BTRFS_METADATA_ITEM_KEY)
814 last = key.objectid +
815 fs_info->nodesize;
816 else
817 last = key.objectid + key.offset;
818
819 if (total_found > CACHING_CTL_WAKE_UP) {
820 total_found = 0;
821 if (wakeup) {
822 atomic_inc(&caching_ctl->progress);
823 wake_up(&caching_ctl->wait);
824 }
825 }
826 }
827 path->slots[0]++;
828 }
829
830 ret = btrfs_add_new_free_space(block_group, last,
831 block_group->start + block_group->length,
832 NULL);
833out:
834 btrfs_free_path(path);
835 return ret;
836}
837
838static inline void btrfs_free_excluded_extents(const struct btrfs_block_group *bg)
839{
840 clear_extent_bits(&bg->fs_info->excluded_extents, bg->start,
841 bg->start + bg->length - 1, EXTENT_UPTODATE);
842}
843
844static noinline void caching_thread(struct btrfs_work *work)
845{
846 struct btrfs_block_group *block_group;
847 struct btrfs_fs_info *fs_info;
848 struct btrfs_caching_control *caching_ctl;
849 int ret;
850
851 caching_ctl = container_of(work, struct btrfs_caching_control, work);
852 block_group = caching_ctl->block_group;
853 fs_info = block_group->fs_info;
854
855 mutex_lock(&caching_ctl->mutex);
856 down_read(&fs_info->commit_root_sem);
857
858 load_block_group_size_class(caching_ctl, block_group);
859 if (btrfs_test_opt(fs_info, SPACE_CACHE)) {
860 ret = load_free_space_cache(block_group);
861 if (ret == 1) {
862 ret = 0;
863 goto done;
864 }
865
866 /*
867 * We failed to load the space cache, set ourselves to
868 * CACHE_STARTED and carry on.
869 */
870 spin_lock(&block_group->lock);
871 block_group->cached = BTRFS_CACHE_STARTED;
872 spin_unlock(&block_group->lock);
873 wake_up(&caching_ctl->wait);
874 }
875
876 /*
877 * If we are in the transaction that populated the free space tree we
878 * can't actually cache from the free space tree as our commit root and
879 * real root are the same, so we could change the contents of the blocks
880 * while caching. Instead do the slow caching in this case, and after
881 * the transaction has committed we will be safe.
882 */
883 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) &&
884 !(test_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags)))
885 ret = load_free_space_tree(caching_ctl);
886 else
887 ret = load_extent_tree_free(caching_ctl);
888done:
889 spin_lock(&block_group->lock);
890 block_group->caching_ctl = NULL;
891 block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED;
892 spin_unlock(&block_group->lock);
893
894#ifdef CONFIG_BTRFS_DEBUG
895 if (btrfs_should_fragment_free_space(block_group)) {
896 u64 bytes_used;
897
898 spin_lock(&block_group->space_info->lock);
899 spin_lock(&block_group->lock);
900 bytes_used = block_group->length - block_group->used;
901 block_group->space_info->bytes_used += bytes_used >> 1;
902 spin_unlock(&block_group->lock);
903 spin_unlock(&block_group->space_info->lock);
904 fragment_free_space(block_group);
905 }
906#endif
907
908 up_read(&fs_info->commit_root_sem);
909 btrfs_free_excluded_extents(block_group);
910 mutex_unlock(&caching_ctl->mutex);
911
912 wake_up(&caching_ctl->wait);
913
914 btrfs_put_caching_control(caching_ctl);
915 btrfs_put_block_group(block_group);
916}
917
918int btrfs_cache_block_group(struct btrfs_block_group *cache, bool wait)
919{
920 struct btrfs_fs_info *fs_info = cache->fs_info;
921 struct btrfs_caching_control *caching_ctl = NULL;
922 int ret = 0;
923
924 /* Allocator for zoned filesystems does not use the cache at all */
925 if (btrfs_is_zoned(fs_info))
926 return 0;
927
928 caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
929 if (!caching_ctl)
930 return -ENOMEM;
931
932 INIT_LIST_HEAD(&caching_ctl->list);
933 mutex_init(&caching_ctl->mutex);
934 init_waitqueue_head(&caching_ctl->wait);
935 caching_ctl->block_group = cache;
936 refcount_set(&caching_ctl->count, 2);
937 atomic_set(&caching_ctl->progress, 0);
938 btrfs_init_work(&caching_ctl->work, caching_thread, NULL);
939
940 spin_lock(&cache->lock);
941 if (cache->cached != BTRFS_CACHE_NO) {
942 kfree(caching_ctl);
943
944 caching_ctl = cache->caching_ctl;
945 if (caching_ctl)
946 refcount_inc(&caching_ctl->count);
947 spin_unlock(&cache->lock);
948 goto out;
949 }
950 WARN_ON(cache->caching_ctl);
951 cache->caching_ctl = caching_ctl;
952 cache->cached = BTRFS_CACHE_STARTED;
953 spin_unlock(&cache->lock);
954
955 write_lock(&fs_info->block_group_cache_lock);
956 refcount_inc(&caching_ctl->count);
957 list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
958 write_unlock(&fs_info->block_group_cache_lock);
959
960 btrfs_get_block_group(cache);
961
962 btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
963out:
964 if (wait && caching_ctl)
965 ret = btrfs_caching_ctl_wait_done(cache, caching_ctl);
966 if (caching_ctl)
967 btrfs_put_caching_control(caching_ctl);
968
969 return ret;
970}
971
972static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
973{
974 u64 extra_flags = chunk_to_extended(flags) &
975 BTRFS_EXTENDED_PROFILE_MASK;
976
977 write_seqlock(&fs_info->profiles_lock);
978 if (flags & BTRFS_BLOCK_GROUP_DATA)
979 fs_info->avail_data_alloc_bits &= ~extra_flags;
980 if (flags & BTRFS_BLOCK_GROUP_METADATA)
981 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
982 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
983 fs_info->avail_system_alloc_bits &= ~extra_flags;
984 write_sequnlock(&fs_info->profiles_lock);
985}
986
987/*
988 * Clear incompat bits for the following feature(s):
989 *
990 * - RAID56 - in case there's neither RAID5 nor RAID6 profile block group
991 * in the whole filesystem
992 *
993 * - RAID1C34 - same as above for RAID1C3 and RAID1C4 block groups
994 */
995static void clear_incompat_bg_bits(struct btrfs_fs_info *fs_info, u64 flags)
996{
997 bool found_raid56 = false;
998 bool found_raid1c34 = false;
999
1000 if ((flags & BTRFS_BLOCK_GROUP_RAID56_MASK) ||
1001 (flags & BTRFS_BLOCK_GROUP_RAID1C3) ||
1002 (flags & BTRFS_BLOCK_GROUP_RAID1C4)) {
1003 struct list_head *head = &fs_info->space_info;
1004 struct btrfs_space_info *sinfo;
1005
1006 list_for_each_entry_rcu(sinfo, head, list) {
1007 down_read(&sinfo->groups_sem);
1008 if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID5]))
1009 found_raid56 = true;
1010 if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID6]))
1011 found_raid56 = true;
1012 if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID1C3]))
1013 found_raid1c34 = true;
1014 if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID1C4]))
1015 found_raid1c34 = true;
1016 up_read(&sinfo->groups_sem);
1017 }
1018 if (!found_raid56)
1019 btrfs_clear_fs_incompat(fs_info, RAID56);
1020 if (!found_raid1c34)
1021 btrfs_clear_fs_incompat(fs_info, RAID1C34);
1022 }
1023}
1024
1025static int remove_block_group_item(struct btrfs_trans_handle *trans,
1026 struct btrfs_path *path,
1027 struct btrfs_block_group *block_group)
1028{
1029 struct btrfs_fs_info *fs_info = trans->fs_info;
1030 struct btrfs_root *root;
1031 struct btrfs_key key;
1032 int ret;
1033
1034 root = btrfs_block_group_root(fs_info);
1035 key.objectid = block_group->start;
1036 key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
1037 key.offset = block_group->length;
1038
1039 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1040 if (ret > 0)
1041 ret = -ENOENT;
1042 if (ret < 0)
1043 return ret;
1044
1045 ret = btrfs_del_item(trans, root, path);
1046 return ret;
1047}
1048
1049int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
1050 struct btrfs_chunk_map *map)
1051{
1052 struct btrfs_fs_info *fs_info = trans->fs_info;
1053 struct btrfs_path *path;
1054 struct btrfs_block_group *block_group;
1055 struct btrfs_free_cluster *cluster;
1056 struct inode *inode;
1057 struct kobject *kobj = NULL;
1058 int ret;
1059 int index;
1060 int factor;
1061 struct btrfs_caching_control *caching_ctl = NULL;
1062 bool remove_map;
1063 bool remove_rsv = false;
1064
1065 block_group = btrfs_lookup_block_group(fs_info, map->start);
1066 BUG_ON(!block_group);
1067 BUG_ON(!block_group->ro);
1068
1069 trace_btrfs_remove_block_group(block_group);
1070 /*
1071 * Free the reserved super bytes from this block group before
1072 * remove it.
1073 */
1074 btrfs_free_excluded_extents(block_group);
1075 btrfs_free_ref_tree_range(fs_info, block_group->start,
1076 block_group->length);
1077
1078 index = btrfs_bg_flags_to_raid_index(block_group->flags);
1079 factor = btrfs_bg_type_to_factor(block_group->flags);
1080
1081 /* make sure this block group isn't part of an allocation cluster */
1082 cluster = &fs_info->data_alloc_cluster;
1083 spin_lock(&cluster->refill_lock);
1084 btrfs_return_cluster_to_free_space(block_group, cluster);
1085 spin_unlock(&cluster->refill_lock);
1086
1087 /*
1088 * make sure this block group isn't part of a metadata
1089 * allocation cluster
1090 */
1091 cluster = &fs_info->meta_alloc_cluster;
1092 spin_lock(&cluster->refill_lock);
1093 btrfs_return_cluster_to_free_space(block_group, cluster);
1094 spin_unlock(&cluster->refill_lock);
1095
1096 btrfs_clear_treelog_bg(block_group);
1097 btrfs_clear_data_reloc_bg(block_group);
1098
1099 path = btrfs_alloc_path();
1100 if (!path) {
1101 ret = -ENOMEM;
1102 goto out;
1103 }
1104
1105 /*
1106 * get the inode first so any iput calls done for the io_list
1107 * aren't the final iput (no unlinks allowed now)
1108 */
1109 inode = lookup_free_space_inode(block_group, path);
1110
1111 mutex_lock(&trans->transaction->cache_write_mutex);
1112 /*
1113 * Make sure our free space cache IO is done before removing the
1114 * free space inode
1115 */
1116 spin_lock(&trans->transaction->dirty_bgs_lock);
1117 if (!list_empty(&block_group->io_list)) {
1118 list_del_init(&block_group->io_list);
1119
1120 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
1121
1122 spin_unlock(&trans->transaction->dirty_bgs_lock);
1123 btrfs_wait_cache_io(trans, block_group, path);
1124 btrfs_put_block_group(block_group);
1125 spin_lock(&trans->transaction->dirty_bgs_lock);
1126 }
1127
1128 if (!list_empty(&block_group->dirty_list)) {
1129 list_del_init(&block_group->dirty_list);
1130 remove_rsv = true;
1131 btrfs_put_block_group(block_group);
1132 }
1133 spin_unlock(&trans->transaction->dirty_bgs_lock);
1134 mutex_unlock(&trans->transaction->cache_write_mutex);
1135
1136 ret = btrfs_remove_free_space_inode(trans, inode, block_group);
1137 if (ret)
1138 goto out;
1139
1140 write_lock(&fs_info->block_group_cache_lock);
1141 rb_erase_cached(&block_group->cache_node,
1142 &fs_info->block_group_cache_tree);
1143 RB_CLEAR_NODE(&block_group->cache_node);
1144
1145 /* Once for the block groups rbtree */
1146 btrfs_put_block_group(block_group);
1147
1148 write_unlock(&fs_info->block_group_cache_lock);
1149
1150 down_write(&block_group->space_info->groups_sem);
1151 /*
1152 * we must use list_del_init so people can check to see if they
1153 * are still on the list after taking the semaphore
1154 */
1155 list_del_init(&block_group->list);
1156 if (list_empty(&block_group->space_info->block_groups[index])) {
1157 kobj = block_group->space_info->block_group_kobjs[index];
1158 block_group->space_info->block_group_kobjs[index] = NULL;
1159 clear_avail_alloc_bits(fs_info, block_group->flags);
1160 }
1161 up_write(&block_group->space_info->groups_sem);
1162 clear_incompat_bg_bits(fs_info, block_group->flags);
1163 if (kobj) {
1164 kobject_del(kobj);
1165 kobject_put(kobj);
1166 }
1167
1168 if (block_group->cached == BTRFS_CACHE_STARTED)
1169 btrfs_wait_block_group_cache_done(block_group);
1170
1171 write_lock(&fs_info->block_group_cache_lock);
1172 caching_ctl = btrfs_get_caching_control(block_group);
1173 if (!caching_ctl) {
1174 struct btrfs_caching_control *ctl;
1175
1176 list_for_each_entry(ctl, &fs_info->caching_block_groups, list) {
1177 if (ctl->block_group == block_group) {
1178 caching_ctl = ctl;
1179 refcount_inc(&caching_ctl->count);
1180 break;
1181 }
1182 }
1183 }
1184 if (caching_ctl)
1185 list_del_init(&caching_ctl->list);
1186 write_unlock(&fs_info->block_group_cache_lock);
1187
1188 if (caching_ctl) {
1189 /* Once for the caching bgs list and once for us. */
1190 btrfs_put_caching_control(caching_ctl);
1191 btrfs_put_caching_control(caching_ctl);
1192 }
1193
1194 spin_lock(&trans->transaction->dirty_bgs_lock);
1195 WARN_ON(!list_empty(&block_group->dirty_list));
1196 WARN_ON(!list_empty(&block_group->io_list));
1197 spin_unlock(&trans->transaction->dirty_bgs_lock);
1198
1199 btrfs_remove_free_space_cache(block_group);
1200
1201 spin_lock(&block_group->space_info->lock);
1202 list_del_init(&block_group->ro_list);
1203
1204 if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
1205 WARN_ON(block_group->space_info->total_bytes
1206 < block_group->length);
1207 WARN_ON(block_group->space_info->bytes_readonly
1208 < block_group->length - block_group->zone_unusable);
1209 WARN_ON(block_group->space_info->bytes_zone_unusable
1210 < block_group->zone_unusable);
1211 WARN_ON(block_group->space_info->disk_total
1212 < block_group->length * factor);
1213 }
1214 block_group->space_info->total_bytes -= block_group->length;
1215 block_group->space_info->bytes_readonly -=
1216 (block_group->length - block_group->zone_unusable);
1217 block_group->space_info->bytes_zone_unusable -=
1218 block_group->zone_unusable;
1219 block_group->space_info->disk_total -= block_group->length * factor;
1220
1221 spin_unlock(&block_group->space_info->lock);
1222
1223 /*
1224 * Remove the free space for the block group from the free space tree
1225 * and the block group's item from the extent tree before marking the
1226 * block group as removed. This is to prevent races with tasks that
1227 * freeze and unfreeze a block group, this task and another task
1228 * allocating a new block group - the unfreeze task ends up removing
1229 * the block group's extent map before the task calling this function
1230 * deletes the block group item from the extent tree, allowing for
1231 * another task to attempt to create another block group with the same
1232 * item key (and failing with -EEXIST and a transaction abort).
1233 */
1234 ret = remove_block_group_free_space(trans, block_group);
1235 if (ret)
1236 goto out;
1237
1238 ret = remove_block_group_item(trans, path, block_group);
1239 if (ret < 0)
1240 goto out;
1241
1242 spin_lock(&block_group->lock);
1243 set_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags);
1244
1245 /*
1246 * At this point trimming or scrub can't start on this block group,
1247 * because we removed the block group from the rbtree
1248 * fs_info->block_group_cache_tree so no one can't find it anymore and
1249 * even if someone already got this block group before we removed it
1250 * from the rbtree, they have already incremented block_group->frozen -
1251 * if they didn't, for the trimming case they won't find any free space
1252 * entries because we already removed them all when we called
1253 * btrfs_remove_free_space_cache().
1254 *
1255 * And we must not remove the chunk map from the fs_info->mapping_tree
1256 * to prevent the same logical address range and physical device space
1257 * ranges from being reused for a new block group. This is needed to
1258 * avoid races with trimming and scrub.
1259 *
1260 * An fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
1261 * completely transactionless, so while it is trimming a range the
1262 * currently running transaction might finish and a new one start,
1263 * allowing for new block groups to be created that can reuse the same
1264 * physical device locations unless we take this special care.
1265 *
1266 * There may also be an implicit trim operation if the file system
1267 * is mounted with -odiscard. The same protections must remain
1268 * in place until the extents have been discarded completely when
1269 * the transaction commit has completed.
1270 */
1271 remove_map = (atomic_read(&block_group->frozen) == 0);
1272 spin_unlock(&block_group->lock);
1273
1274 if (remove_map)
1275 btrfs_remove_chunk_map(fs_info, map);
1276
1277out:
1278 /* Once for the lookup reference */
1279 btrfs_put_block_group(block_group);
1280 if (remove_rsv)
1281 btrfs_dec_delayed_refs_rsv_bg_updates(fs_info);
1282 btrfs_free_path(path);
1283 return ret;
1284}
1285
1286struct btrfs_trans_handle *btrfs_start_trans_remove_block_group(
1287 struct btrfs_fs_info *fs_info, const u64 chunk_offset)
1288{
1289 struct btrfs_root *root = btrfs_block_group_root(fs_info);
1290 struct btrfs_chunk_map *map;
1291 unsigned int num_items;
1292
1293 map = btrfs_find_chunk_map(fs_info, chunk_offset, 1);
1294 ASSERT(map != NULL);
1295 ASSERT(map->start == chunk_offset);
1296
1297 /*
1298 * We need to reserve 3 + N units from the metadata space info in order
1299 * to remove a block group (done at btrfs_remove_chunk() and at
1300 * btrfs_remove_block_group()), which are used for:
1301 *
1302 * 1 unit for adding the free space inode's orphan (located in the tree
1303 * of tree roots).
1304 * 1 unit for deleting the block group item (located in the extent
1305 * tree).
1306 * 1 unit for deleting the free space item (located in tree of tree
1307 * roots).
1308 * N units for deleting N device extent items corresponding to each
1309 * stripe (located in the device tree).
1310 *
1311 * In order to remove a block group we also need to reserve units in the
1312 * system space info in order to update the chunk tree (update one or
1313 * more device items and remove one chunk item), but this is done at
1314 * btrfs_remove_chunk() through a call to check_system_chunk().
1315 */
1316 num_items = 3 + map->num_stripes;
1317 btrfs_free_chunk_map(map);
1318
1319 return btrfs_start_transaction_fallback_global_rsv(root, num_items);
1320}
1321
1322/*
1323 * Mark block group @cache read-only, so later write won't happen to block
1324 * group @cache.
1325 *
1326 * If @force is not set, this function will only mark the block group readonly
1327 * if we have enough free space (1M) in other metadata/system block groups.
1328 * If @force is not set, this function will mark the block group readonly
1329 * without checking free space.
1330 *
1331 * NOTE: This function doesn't care if other block groups can contain all the
1332 * data in this block group. That check should be done by relocation routine,
1333 * not this function.
1334 */
1335static int inc_block_group_ro(struct btrfs_block_group *cache, int force)
1336{
1337 struct btrfs_space_info *sinfo = cache->space_info;
1338 u64 num_bytes;
1339 int ret = -ENOSPC;
1340
1341 spin_lock(&sinfo->lock);
1342 spin_lock(&cache->lock);
1343
1344 if (cache->swap_extents) {
1345 ret = -ETXTBSY;
1346 goto out;
1347 }
1348
1349 if (cache->ro) {
1350 cache->ro++;
1351 ret = 0;
1352 goto out;
1353 }
1354
1355 num_bytes = cache->length - cache->reserved - cache->pinned -
1356 cache->bytes_super - cache->zone_unusable - cache->used;
1357
1358 /*
1359 * Data never overcommits, even in mixed mode, so do just the straight
1360 * check of left over space in how much we have allocated.
1361 */
1362 if (force) {
1363 ret = 0;
1364 } else if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA) {
1365 u64 sinfo_used = btrfs_space_info_used(sinfo, true);
1366
1367 /*
1368 * Here we make sure if we mark this bg RO, we still have enough
1369 * free space as buffer.
1370 */
1371 if (sinfo_used + num_bytes <= sinfo->total_bytes)
1372 ret = 0;
1373 } else {
1374 /*
1375 * We overcommit metadata, so we need to do the
1376 * btrfs_can_overcommit check here, and we need to pass in
1377 * BTRFS_RESERVE_NO_FLUSH to give ourselves the most amount of
1378 * leeway to allow us to mark this block group as read only.
1379 */
1380 if (btrfs_can_overcommit(cache->fs_info, sinfo, num_bytes,
1381 BTRFS_RESERVE_NO_FLUSH))
1382 ret = 0;
1383 }
1384
1385 if (!ret) {
1386 sinfo->bytes_readonly += num_bytes;
1387 if (btrfs_is_zoned(cache->fs_info)) {
1388 /* Migrate zone_unusable bytes to readonly */
1389 sinfo->bytes_readonly += cache->zone_unusable;
1390 sinfo->bytes_zone_unusable -= cache->zone_unusable;
1391 cache->zone_unusable = 0;
1392 }
1393 cache->ro++;
1394 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
1395 }
1396out:
1397 spin_unlock(&cache->lock);
1398 spin_unlock(&sinfo->lock);
1399 if (ret == -ENOSPC && btrfs_test_opt(cache->fs_info, ENOSPC_DEBUG)) {
1400 btrfs_info(cache->fs_info,
1401 "unable to make block group %llu ro", cache->start);
1402 btrfs_dump_space_info(cache->fs_info, cache->space_info, 0, 0);
1403 }
1404 return ret;
1405}
1406
1407static bool clean_pinned_extents(struct btrfs_trans_handle *trans,
1408 struct btrfs_block_group *bg)
1409{
1410 struct btrfs_fs_info *fs_info = bg->fs_info;
1411 struct btrfs_transaction *prev_trans = NULL;
1412 const u64 start = bg->start;
1413 const u64 end = start + bg->length - 1;
1414 int ret;
1415
1416 spin_lock(&fs_info->trans_lock);
1417 if (trans->transaction->list.prev != &fs_info->trans_list) {
1418 prev_trans = list_last_entry(&trans->transaction->list,
1419 struct btrfs_transaction, list);
1420 refcount_inc(&prev_trans->use_count);
1421 }
1422 spin_unlock(&fs_info->trans_lock);
1423
1424 /*
1425 * Hold the unused_bg_unpin_mutex lock to avoid racing with
1426 * btrfs_finish_extent_commit(). If we are at transaction N, another
1427 * task might be running finish_extent_commit() for the previous
1428 * transaction N - 1, and have seen a range belonging to the block
1429 * group in pinned_extents before we were able to clear the whole block
1430 * group range from pinned_extents. This means that task can lookup for
1431 * the block group after we unpinned it from pinned_extents and removed
1432 * it, leading to a BUG_ON() at unpin_extent_range().
1433 */
1434 mutex_lock(&fs_info->unused_bg_unpin_mutex);
1435 if (prev_trans) {
1436 ret = clear_extent_bits(&prev_trans->pinned_extents, start, end,
1437 EXTENT_DIRTY);
1438 if (ret)
1439 goto out;
1440 }
1441
1442 ret = clear_extent_bits(&trans->transaction->pinned_extents, start, end,
1443 EXTENT_DIRTY);
1444out:
1445 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
1446 if (prev_trans)
1447 btrfs_put_transaction(prev_trans);
1448
1449 return ret == 0;
1450}
1451
1452/*
1453 * Process the unused_bgs list and remove any that don't have any allocated
1454 * space inside of them.
1455 */
1456void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
1457{
1458 LIST_HEAD(retry_list);
1459 struct btrfs_block_group *block_group;
1460 struct btrfs_space_info *space_info;
1461 struct btrfs_trans_handle *trans;
1462 const bool async_trim_enabled = btrfs_test_opt(fs_info, DISCARD_ASYNC);
1463 int ret = 0;
1464
1465 if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
1466 return;
1467
1468 if (btrfs_fs_closing(fs_info))
1469 return;
1470
1471 /*
1472 * Long running balances can keep us blocked here for eternity, so
1473 * simply skip deletion if we're unable to get the mutex.
1474 */
1475 if (!mutex_trylock(&fs_info->reclaim_bgs_lock))
1476 return;
1477
1478 spin_lock(&fs_info->unused_bgs_lock);
1479 while (!list_empty(&fs_info->unused_bgs)) {
1480 u64 used;
1481 int trimming;
1482
1483 block_group = list_first_entry(&fs_info->unused_bgs,
1484 struct btrfs_block_group,
1485 bg_list);
1486 list_del_init(&block_group->bg_list);
1487
1488 space_info = block_group->space_info;
1489
1490 if (ret || btrfs_mixed_space_info(space_info)) {
1491 btrfs_put_block_group(block_group);
1492 continue;
1493 }
1494 spin_unlock(&fs_info->unused_bgs_lock);
1495
1496 btrfs_discard_cancel_work(&fs_info->discard_ctl, block_group);
1497
1498 /* Don't want to race with allocators so take the groups_sem */
1499 down_write(&space_info->groups_sem);
1500
1501 /*
1502 * Async discard moves the final block group discard to be prior
1503 * to the unused_bgs code path. Therefore, if it's not fully
1504 * trimmed, punt it back to the async discard lists.
1505 */
1506 if (btrfs_test_opt(fs_info, DISCARD_ASYNC) &&
1507 !btrfs_is_free_space_trimmed(block_group)) {
1508 trace_btrfs_skip_unused_block_group(block_group);
1509 up_write(&space_info->groups_sem);
1510 /* Requeue if we failed because of async discard */
1511 btrfs_discard_queue_work(&fs_info->discard_ctl,
1512 block_group);
1513 goto next;
1514 }
1515
1516 spin_lock(&space_info->lock);
1517 spin_lock(&block_group->lock);
1518 if (btrfs_is_block_group_used(block_group) || block_group->ro ||
1519 list_is_singular(&block_group->list)) {
1520 /*
1521 * We want to bail if we made new allocations or have
1522 * outstanding allocations in this block group. We do
1523 * the ro check in case balance is currently acting on
1524 * this block group.
1525 */
1526 trace_btrfs_skip_unused_block_group(block_group);
1527 spin_unlock(&block_group->lock);
1528 spin_unlock(&space_info->lock);
1529 up_write(&space_info->groups_sem);
1530 goto next;
1531 }
1532
1533 /*
1534 * The block group may be unused but there may be space reserved
1535 * accounting with the existence of that block group, that is,
1536 * space_info->bytes_may_use was incremented by a task but no
1537 * space was yet allocated from the block group by the task.
1538 * That space may or may not be allocated, as we are generally
1539 * pessimistic about space reservation for metadata as well as
1540 * for data when using compression (as we reserve space based on
1541 * the worst case, when data can't be compressed, and before
1542 * actually attempting compression, before starting writeback).
1543 *
1544 * So check if the total space of the space_info minus the size
1545 * of this block group is less than the used space of the
1546 * space_info - if that's the case, then it means we have tasks
1547 * that might be relying on the block group in order to allocate
1548 * extents, and add back the block group to the unused list when
1549 * we finish, so that we retry later in case no tasks ended up
1550 * needing to allocate extents from the block group.
1551 */
1552 used = btrfs_space_info_used(space_info, true);
1553 if (space_info->total_bytes - block_group->length < used) {
1554 /*
1555 * Add a reference for the list, compensate for the ref
1556 * drop under the "next" label for the
1557 * fs_info->unused_bgs list.
1558 */
1559 btrfs_get_block_group(block_group);
1560 list_add_tail(&block_group->bg_list, &retry_list);
1561
1562 trace_btrfs_skip_unused_block_group(block_group);
1563 spin_unlock(&block_group->lock);
1564 spin_unlock(&space_info->lock);
1565 up_write(&space_info->groups_sem);
1566 goto next;
1567 }
1568
1569 spin_unlock(&block_group->lock);
1570 spin_unlock(&space_info->lock);
1571
1572 /* We don't want to force the issue, only flip if it's ok. */
1573 ret = inc_block_group_ro(block_group, 0);
1574 up_write(&space_info->groups_sem);
1575 if (ret < 0) {
1576 ret = 0;
1577 goto next;
1578 }
1579
1580 ret = btrfs_zone_finish(block_group);
1581 if (ret < 0) {
1582 btrfs_dec_block_group_ro(block_group);
1583 if (ret == -EAGAIN)
1584 ret = 0;
1585 goto next;
1586 }
1587
1588 /*
1589 * Want to do this before we do anything else so we can recover
1590 * properly if we fail to join the transaction.
1591 */
1592 trans = btrfs_start_trans_remove_block_group(fs_info,
1593 block_group->start);
1594 if (IS_ERR(trans)) {
1595 btrfs_dec_block_group_ro(block_group);
1596 ret = PTR_ERR(trans);
1597 goto next;
1598 }
1599
1600 /*
1601 * We could have pending pinned extents for this block group,
1602 * just delete them, we don't care about them anymore.
1603 */
1604 if (!clean_pinned_extents(trans, block_group)) {
1605 btrfs_dec_block_group_ro(block_group);
1606 goto end_trans;
1607 }
1608
1609 /*
1610 * At this point, the block_group is read only and should fail
1611 * new allocations. However, btrfs_finish_extent_commit() can
1612 * cause this block_group to be placed back on the discard
1613 * lists because now the block_group isn't fully discarded.
1614 * Bail here and try again later after discarding everything.
1615 */
1616 spin_lock(&fs_info->discard_ctl.lock);
1617 if (!list_empty(&block_group->discard_list)) {
1618 spin_unlock(&fs_info->discard_ctl.lock);
1619 btrfs_dec_block_group_ro(block_group);
1620 btrfs_discard_queue_work(&fs_info->discard_ctl,
1621 block_group);
1622 goto end_trans;
1623 }
1624 spin_unlock(&fs_info->discard_ctl.lock);
1625
1626 /* Reset pinned so btrfs_put_block_group doesn't complain */
1627 spin_lock(&space_info->lock);
1628 spin_lock(&block_group->lock);
1629
1630 btrfs_space_info_update_bytes_pinned(fs_info, space_info,
1631 -block_group->pinned);
1632 space_info->bytes_readonly += block_group->pinned;
1633 block_group->pinned = 0;
1634
1635 spin_unlock(&block_group->lock);
1636 spin_unlock(&space_info->lock);
1637
1638 /*
1639 * The normal path here is an unused block group is passed here,
1640 * then trimming is handled in the transaction commit path.
1641 * Async discard interposes before this to do the trimming
1642 * before coming down the unused block group path as trimming
1643 * will no longer be done later in the transaction commit path.
1644 */
1645 if (!async_trim_enabled && btrfs_test_opt(fs_info, DISCARD_ASYNC))
1646 goto flip_async;
1647
1648 /*
1649 * DISCARD can flip during remount. On zoned filesystems, we
1650 * need to reset sequential-required zones.
1651 */
1652 trimming = btrfs_test_opt(fs_info, DISCARD_SYNC) ||
1653 btrfs_is_zoned(fs_info);
1654
1655 /* Implicit trim during transaction commit. */
1656 if (trimming)
1657 btrfs_freeze_block_group(block_group);
1658
1659 /*
1660 * Btrfs_remove_chunk will abort the transaction if things go
1661 * horribly wrong.
1662 */
1663 ret = btrfs_remove_chunk(trans, block_group->start);
1664
1665 if (ret) {
1666 if (trimming)
1667 btrfs_unfreeze_block_group(block_group);
1668 goto end_trans;
1669 }
1670
1671 /*
1672 * If we're not mounted with -odiscard, we can just forget
1673 * about this block group. Otherwise we'll need to wait
1674 * until transaction commit to do the actual discard.
1675 */
1676 if (trimming) {
1677 spin_lock(&fs_info->unused_bgs_lock);
1678 /*
1679 * A concurrent scrub might have added us to the list
1680 * fs_info->unused_bgs, so use a list_move operation
1681 * to add the block group to the deleted_bgs list.
1682 */
1683 list_move(&block_group->bg_list,
1684 &trans->transaction->deleted_bgs);
1685 spin_unlock(&fs_info->unused_bgs_lock);
1686 btrfs_get_block_group(block_group);
1687 }
1688end_trans:
1689 btrfs_end_transaction(trans);
1690next:
1691 btrfs_put_block_group(block_group);
1692 spin_lock(&fs_info->unused_bgs_lock);
1693 }
1694 list_splice_tail(&retry_list, &fs_info->unused_bgs);
1695 spin_unlock(&fs_info->unused_bgs_lock);
1696 mutex_unlock(&fs_info->reclaim_bgs_lock);
1697 return;
1698
1699flip_async:
1700 btrfs_end_transaction(trans);
1701 spin_lock(&fs_info->unused_bgs_lock);
1702 list_splice_tail(&retry_list, &fs_info->unused_bgs);
1703 spin_unlock(&fs_info->unused_bgs_lock);
1704 mutex_unlock(&fs_info->reclaim_bgs_lock);
1705 btrfs_put_block_group(block_group);
1706 btrfs_discard_punt_unused_bgs_list(fs_info);
1707}
1708
1709void btrfs_mark_bg_unused(struct btrfs_block_group *bg)
1710{
1711 struct btrfs_fs_info *fs_info = bg->fs_info;
1712
1713 spin_lock(&fs_info->unused_bgs_lock);
1714 if (list_empty(&bg->bg_list)) {
1715 btrfs_get_block_group(bg);
1716 trace_btrfs_add_unused_block_group(bg);
1717 list_add_tail(&bg->bg_list, &fs_info->unused_bgs);
1718 } else if (!test_bit(BLOCK_GROUP_FLAG_NEW, &bg->runtime_flags)) {
1719 /* Pull out the block group from the reclaim_bgs list. */
1720 trace_btrfs_add_unused_block_group(bg);
1721 list_move_tail(&bg->bg_list, &fs_info->unused_bgs);
1722 }
1723 spin_unlock(&fs_info->unused_bgs_lock);
1724}
1725
1726/*
1727 * We want block groups with a low number of used bytes to be in the beginning
1728 * of the list, so they will get reclaimed first.
1729 */
1730static int reclaim_bgs_cmp(void *unused, const struct list_head *a,
1731 const struct list_head *b)
1732{
1733 const struct btrfs_block_group *bg1, *bg2;
1734
1735 bg1 = list_entry(a, struct btrfs_block_group, bg_list);
1736 bg2 = list_entry(b, struct btrfs_block_group, bg_list);
1737
1738 return bg1->used > bg2->used;
1739}
1740
1741static inline bool btrfs_should_reclaim(struct btrfs_fs_info *fs_info)
1742{
1743 if (btrfs_is_zoned(fs_info))
1744 return btrfs_zoned_should_reclaim(fs_info);
1745 return true;
1746}
1747
1748static bool should_reclaim_block_group(struct btrfs_block_group *bg, u64 bytes_freed)
1749{
1750 const struct btrfs_space_info *space_info = bg->space_info;
1751 const int reclaim_thresh = READ_ONCE(space_info->bg_reclaim_threshold);
1752 const u64 new_val = bg->used;
1753 const u64 old_val = new_val + bytes_freed;
1754 u64 thresh;
1755
1756 if (reclaim_thresh == 0)
1757 return false;
1758
1759 thresh = mult_perc(bg->length, reclaim_thresh);
1760
1761 /*
1762 * If we were below the threshold before don't reclaim, we are likely a
1763 * brand new block group and we don't want to relocate new block groups.
1764 */
1765 if (old_val < thresh)
1766 return false;
1767 if (new_val >= thresh)
1768 return false;
1769 return true;
1770}
1771
1772void btrfs_reclaim_bgs_work(struct work_struct *work)
1773{
1774 struct btrfs_fs_info *fs_info =
1775 container_of(work, struct btrfs_fs_info, reclaim_bgs_work);
1776 struct btrfs_block_group *bg;
1777 struct btrfs_space_info *space_info;
1778
1779 if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
1780 return;
1781
1782 if (btrfs_fs_closing(fs_info))
1783 return;
1784
1785 if (!btrfs_should_reclaim(fs_info))
1786 return;
1787
1788 sb_start_write(fs_info->sb);
1789
1790 if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_BALANCE)) {
1791 sb_end_write(fs_info->sb);
1792 return;
1793 }
1794
1795 /*
1796 * Long running balances can keep us blocked here for eternity, so
1797 * simply skip reclaim if we're unable to get the mutex.
1798 */
1799 if (!mutex_trylock(&fs_info->reclaim_bgs_lock)) {
1800 btrfs_exclop_finish(fs_info);
1801 sb_end_write(fs_info->sb);
1802 return;
1803 }
1804
1805 spin_lock(&fs_info->unused_bgs_lock);
1806 /*
1807 * Sort happens under lock because we can't simply splice it and sort.
1808 * The block groups might still be in use and reachable via bg_list,
1809 * and their presence in the reclaim_bgs list must be preserved.
1810 */
1811 list_sort(NULL, &fs_info->reclaim_bgs, reclaim_bgs_cmp);
1812 while (!list_empty(&fs_info->reclaim_bgs)) {
1813 u64 zone_unusable;
1814 int ret = 0;
1815
1816 bg = list_first_entry(&fs_info->reclaim_bgs,
1817 struct btrfs_block_group,
1818 bg_list);
1819 list_del_init(&bg->bg_list);
1820
1821 space_info = bg->space_info;
1822 spin_unlock(&fs_info->unused_bgs_lock);
1823
1824 /* Don't race with allocators so take the groups_sem */
1825 down_write(&space_info->groups_sem);
1826
1827 spin_lock(&bg->lock);
1828 if (bg->reserved || bg->pinned || bg->ro) {
1829 /*
1830 * We want to bail if we made new allocations or have
1831 * outstanding allocations in this block group. We do
1832 * the ro check in case balance is currently acting on
1833 * this block group.
1834 */
1835 spin_unlock(&bg->lock);
1836 up_write(&space_info->groups_sem);
1837 goto next;
1838 }
1839 if (bg->used == 0) {
1840 /*
1841 * It is possible that we trigger relocation on a block
1842 * group as its extents are deleted and it first goes
1843 * below the threshold, then shortly after goes empty.
1844 *
1845 * In this case, relocating it does delete it, but has
1846 * some overhead in relocation specific metadata, looking
1847 * for the non-existent extents and running some extra
1848 * transactions, which we can avoid by using one of the
1849 * other mechanisms for dealing with empty block groups.
1850 */
1851 if (!btrfs_test_opt(fs_info, DISCARD_ASYNC))
1852 btrfs_mark_bg_unused(bg);
1853 spin_unlock(&bg->lock);
1854 up_write(&space_info->groups_sem);
1855 goto next;
1856
1857 }
1858 /*
1859 * The block group might no longer meet the reclaim condition by
1860 * the time we get around to reclaiming it, so to avoid
1861 * reclaiming overly full block_groups, skip reclaiming them.
1862 *
1863 * Since the decision making process also depends on the amount
1864 * being freed, pass in a fake giant value to skip that extra
1865 * check, which is more meaningful when adding to the list in
1866 * the first place.
1867 */
1868 if (!should_reclaim_block_group(bg, bg->length)) {
1869 spin_unlock(&bg->lock);
1870 up_write(&space_info->groups_sem);
1871 goto next;
1872 }
1873 spin_unlock(&bg->lock);
1874
1875 /*
1876 * Get out fast, in case we're read-only or unmounting the
1877 * filesystem. It is OK to drop block groups from the list even
1878 * for the read-only case. As we did sb_start_write(),
1879 * "mount -o remount,ro" won't happen and read-only filesystem
1880 * means it is forced read-only due to a fatal error. So, it
1881 * never gets back to read-write to let us reclaim again.
1882 */
1883 if (btrfs_need_cleaner_sleep(fs_info)) {
1884 up_write(&space_info->groups_sem);
1885 goto next;
1886 }
1887
1888 /*
1889 * Cache the zone_unusable value before turning the block group
1890 * to read only. As soon as the blog group is read only it's
1891 * zone_unusable value gets moved to the block group's read-only
1892 * bytes and isn't available for calculations anymore.
1893 */
1894 zone_unusable = bg->zone_unusable;
1895 ret = inc_block_group_ro(bg, 0);
1896 up_write(&space_info->groups_sem);
1897 if (ret < 0)
1898 goto next;
1899
1900 btrfs_info(fs_info,
1901 "reclaiming chunk %llu with %llu%% used %llu%% unusable",
1902 bg->start,
1903 div64_u64(bg->used * 100, bg->length),
1904 div64_u64(zone_unusable * 100, bg->length));
1905 trace_btrfs_reclaim_block_group(bg);
1906 ret = btrfs_relocate_chunk(fs_info, bg->start);
1907 if (ret) {
1908 btrfs_dec_block_group_ro(bg);
1909 btrfs_err(fs_info, "error relocating chunk %llu",
1910 bg->start);
1911 }
1912
1913next:
1914 if (ret)
1915 btrfs_mark_bg_to_reclaim(bg);
1916 btrfs_put_block_group(bg);
1917
1918 mutex_unlock(&fs_info->reclaim_bgs_lock);
1919 /*
1920 * Reclaiming all the block groups in the list can take really
1921 * long. Prioritize cleaning up unused block groups.
1922 */
1923 btrfs_delete_unused_bgs(fs_info);
1924 /*
1925 * If we are interrupted by a balance, we can just bail out. The
1926 * cleaner thread restart again if necessary.
1927 */
1928 if (!mutex_trylock(&fs_info->reclaim_bgs_lock))
1929 goto end;
1930 spin_lock(&fs_info->unused_bgs_lock);
1931 }
1932 spin_unlock(&fs_info->unused_bgs_lock);
1933 mutex_unlock(&fs_info->reclaim_bgs_lock);
1934end:
1935 btrfs_exclop_finish(fs_info);
1936 sb_end_write(fs_info->sb);
1937}
1938
1939void btrfs_reclaim_bgs(struct btrfs_fs_info *fs_info)
1940{
1941 spin_lock(&fs_info->unused_bgs_lock);
1942 if (!list_empty(&fs_info->reclaim_bgs))
1943 queue_work(system_unbound_wq, &fs_info->reclaim_bgs_work);
1944 spin_unlock(&fs_info->unused_bgs_lock);
1945}
1946
1947void btrfs_mark_bg_to_reclaim(struct btrfs_block_group *bg)
1948{
1949 struct btrfs_fs_info *fs_info = bg->fs_info;
1950
1951 spin_lock(&fs_info->unused_bgs_lock);
1952 if (list_empty(&bg->bg_list)) {
1953 btrfs_get_block_group(bg);
1954 trace_btrfs_add_reclaim_block_group(bg);
1955 list_add_tail(&bg->bg_list, &fs_info->reclaim_bgs);
1956 }
1957 spin_unlock(&fs_info->unused_bgs_lock);
1958}
1959
1960static int read_bg_from_eb(struct btrfs_fs_info *fs_info, struct btrfs_key *key,
1961 struct btrfs_path *path)
1962{
1963 struct btrfs_chunk_map *map;
1964 struct btrfs_block_group_item bg;
1965 struct extent_buffer *leaf;
1966 int slot;
1967 u64 flags;
1968 int ret = 0;
1969
1970 slot = path->slots[0];
1971 leaf = path->nodes[0];
1972
1973 map = btrfs_find_chunk_map(fs_info, key->objectid, key->offset);
1974 if (!map) {
1975 btrfs_err(fs_info,
1976 "logical %llu len %llu found bg but no related chunk",
1977 key->objectid, key->offset);
1978 return -ENOENT;
1979 }
1980
1981 if (map->start != key->objectid || map->chunk_len != key->offset) {
1982 btrfs_err(fs_info,
1983 "block group %llu len %llu mismatch with chunk %llu len %llu",
1984 key->objectid, key->offset, map->start, map->chunk_len);
1985 ret = -EUCLEAN;
1986 goto out_free_map;
1987 }
1988
1989 read_extent_buffer(leaf, &bg, btrfs_item_ptr_offset(leaf, slot),
1990 sizeof(bg));
1991 flags = btrfs_stack_block_group_flags(&bg) &
1992 BTRFS_BLOCK_GROUP_TYPE_MASK;
1993
1994 if (flags != (map->type & BTRFS_BLOCK_GROUP_TYPE_MASK)) {
1995 btrfs_err(fs_info,
1996"block group %llu len %llu type flags 0x%llx mismatch with chunk type flags 0x%llx",
1997 key->objectid, key->offset, flags,
1998 (BTRFS_BLOCK_GROUP_TYPE_MASK & map->type));
1999 ret = -EUCLEAN;
2000 }
2001
2002out_free_map:
2003 btrfs_free_chunk_map(map);
2004 return ret;
2005}
2006
2007static int find_first_block_group(struct btrfs_fs_info *fs_info,
2008 struct btrfs_path *path,
2009 struct btrfs_key *key)
2010{
2011 struct btrfs_root *root = btrfs_block_group_root(fs_info);
2012 int ret;
2013 struct btrfs_key found_key;
2014
2015 btrfs_for_each_slot(root, key, &found_key, path, ret) {
2016 if (found_key.objectid >= key->objectid &&
2017 found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
2018 return read_bg_from_eb(fs_info, &found_key, path);
2019 }
2020 }
2021 return ret;
2022}
2023
2024static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
2025{
2026 u64 extra_flags = chunk_to_extended(flags) &
2027 BTRFS_EXTENDED_PROFILE_MASK;
2028
2029 write_seqlock(&fs_info->profiles_lock);
2030 if (flags & BTRFS_BLOCK_GROUP_DATA)
2031 fs_info->avail_data_alloc_bits |= extra_flags;
2032 if (flags & BTRFS_BLOCK_GROUP_METADATA)
2033 fs_info->avail_metadata_alloc_bits |= extra_flags;
2034 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
2035 fs_info->avail_system_alloc_bits |= extra_flags;
2036 write_sequnlock(&fs_info->profiles_lock);
2037}
2038
2039/*
2040 * Map a physical disk address to a list of logical addresses.
2041 *
2042 * @fs_info: the filesystem
2043 * @chunk_start: logical address of block group
2044 * @physical: physical address to map to logical addresses
2045 * @logical: return array of logical addresses which map to @physical
2046 * @naddrs: length of @logical
2047 * @stripe_len: size of IO stripe for the given block group
2048 *
2049 * Maps a particular @physical disk address to a list of @logical addresses.
2050 * Used primarily to exclude those portions of a block group that contain super
2051 * block copies.
2052 */
2053int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
2054 u64 physical, u64 **logical, int *naddrs, int *stripe_len)
2055{
2056 struct btrfs_chunk_map *map;
2057 u64 *buf;
2058 u64 bytenr;
2059 u64 data_stripe_length;
2060 u64 io_stripe_size;
2061 int i, nr = 0;
2062 int ret = 0;
2063
2064 map = btrfs_get_chunk_map(fs_info, chunk_start, 1);
2065 if (IS_ERR(map))
2066 return -EIO;
2067
2068 data_stripe_length = map->stripe_size;
2069 io_stripe_size = BTRFS_STRIPE_LEN;
2070 chunk_start = map->start;
2071
2072 /* For RAID5/6 adjust to a full IO stripe length */
2073 if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
2074 io_stripe_size = btrfs_stripe_nr_to_offset(nr_data_stripes(map));
2075
2076 buf = kcalloc(map->num_stripes, sizeof(u64), GFP_NOFS);
2077 if (!buf) {
2078 ret = -ENOMEM;
2079 goto out;
2080 }
2081
2082 for (i = 0; i < map->num_stripes; i++) {
2083 bool already_inserted = false;
2084 u32 stripe_nr;
2085 u32 offset;
2086 int j;
2087
2088 if (!in_range(physical, map->stripes[i].physical,
2089 data_stripe_length))
2090 continue;
2091
2092 stripe_nr = (physical - map->stripes[i].physical) >>
2093 BTRFS_STRIPE_LEN_SHIFT;
2094 offset = (physical - map->stripes[i].physical) &
2095 BTRFS_STRIPE_LEN_MASK;
2096
2097 if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
2098 BTRFS_BLOCK_GROUP_RAID10))
2099 stripe_nr = div_u64(stripe_nr * map->num_stripes + i,
2100 map->sub_stripes);
2101 /*
2102 * The remaining case would be for RAID56, multiply by
2103 * nr_data_stripes(). Alternatively, just use rmap_len below
2104 * instead of map->stripe_len
2105 */
2106 bytenr = chunk_start + stripe_nr * io_stripe_size + offset;
2107
2108 /* Ensure we don't add duplicate addresses */
2109 for (j = 0; j < nr; j++) {
2110 if (buf[j] == bytenr) {
2111 already_inserted = true;
2112 break;
2113 }
2114 }
2115
2116 if (!already_inserted)
2117 buf[nr++] = bytenr;
2118 }
2119
2120 *logical = buf;
2121 *naddrs = nr;
2122 *stripe_len = io_stripe_size;
2123out:
2124 btrfs_free_chunk_map(map);
2125 return ret;
2126}
2127
2128static int exclude_super_stripes(struct btrfs_block_group *cache)
2129{
2130 struct btrfs_fs_info *fs_info = cache->fs_info;
2131 const bool zoned = btrfs_is_zoned(fs_info);
2132 u64 bytenr;
2133 u64 *logical;
2134 int stripe_len;
2135 int i, nr, ret;
2136
2137 if (cache->start < BTRFS_SUPER_INFO_OFFSET) {
2138 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->start;
2139 cache->bytes_super += stripe_len;
2140 ret = set_extent_bit(&fs_info->excluded_extents, cache->start,
2141 cache->start + stripe_len - 1,
2142 EXTENT_UPTODATE, NULL);
2143 if (ret)
2144 return ret;
2145 }
2146
2147 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
2148 bytenr = btrfs_sb_offset(i);
2149 ret = btrfs_rmap_block(fs_info, cache->start,
2150 bytenr, &logical, &nr, &stripe_len);
2151 if (ret)
2152 return ret;
2153
2154 /* Shouldn't have super stripes in sequential zones */
2155 if (zoned && nr) {
2156 kfree(logical);
2157 btrfs_err(fs_info,
2158 "zoned: block group %llu must not contain super block",
2159 cache->start);
2160 return -EUCLEAN;
2161 }
2162
2163 while (nr--) {
2164 u64 len = min_t(u64, stripe_len,
2165 cache->start + cache->length - logical[nr]);
2166
2167 cache->bytes_super += len;
2168 ret = set_extent_bit(&fs_info->excluded_extents, logical[nr],
2169 logical[nr] + len - 1,
2170 EXTENT_UPTODATE, NULL);
2171 if (ret) {
2172 kfree(logical);
2173 return ret;
2174 }
2175 }
2176
2177 kfree(logical);
2178 }
2179 return 0;
2180}
2181
2182static struct btrfs_block_group *btrfs_create_block_group_cache(
2183 struct btrfs_fs_info *fs_info, u64 start)
2184{
2185 struct btrfs_block_group *cache;
2186
2187 cache = kzalloc(sizeof(*cache), GFP_NOFS);
2188 if (!cache)
2189 return NULL;
2190
2191 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
2192 GFP_NOFS);
2193 if (!cache->free_space_ctl) {
2194 kfree(cache);
2195 return NULL;
2196 }
2197
2198 cache->start = start;
2199
2200 cache->fs_info = fs_info;
2201 cache->full_stripe_len = btrfs_full_stripe_len(fs_info, start);
2202
2203 cache->discard_index = BTRFS_DISCARD_INDEX_UNUSED;
2204
2205 refcount_set(&cache->refs, 1);
2206 spin_lock_init(&cache->lock);
2207 init_rwsem(&cache->data_rwsem);
2208 INIT_LIST_HEAD(&cache->list);
2209 INIT_LIST_HEAD(&cache->cluster_list);
2210 INIT_LIST_HEAD(&cache->bg_list);
2211 INIT_LIST_HEAD(&cache->ro_list);
2212 INIT_LIST_HEAD(&cache->discard_list);
2213 INIT_LIST_HEAD(&cache->dirty_list);
2214 INIT_LIST_HEAD(&cache->io_list);
2215 INIT_LIST_HEAD(&cache->active_bg_list);
2216 btrfs_init_free_space_ctl(cache, cache->free_space_ctl);
2217 atomic_set(&cache->frozen, 0);
2218 mutex_init(&cache->free_space_lock);
2219
2220 return cache;
2221}
2222
2223/*
2224 * Iterate all chunks and verify that each of them has the corresponding block
2225 * group
2226 */
2227static int check_chunk_block_group_mappings(struct btrfs_fs_info *fs_info)
2228{
2229 u64 start = 0;
2230 int ret = 0;
2231
2232 while (1) {
2233 struct btrfs_chunk_map *map;
2234 struct btrfs_block_group *bg;
2235
2236 /*
2237 * btrfs_find_chunk_map() will return the first chunk map
2238 * intersecting the range, so setting @length to 1 is enough to
2239 * get the first chunk.
2240 */
2241 map = btrfs_find_chunk_map(fs_info, start, 1);
2242 if (!map)
2243 break;
2244
2245 bg = btrfs_lookup_block_group(fs_info, map->start);
2246 if (!bg) {
2247 btrfs_err(fs_info,
2248 "chunk start=%llu len=%llu doesn't have corresponding block group",
2249 map->start, map->chunk_len);
2250 ret = -EUCLEAN;
2251 btrfs_free_chunk_map(map);
2252 break;
2253 }
2254 if (bg->start != map->start || bg->length != map->chunk_len ||
2255 (bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK) !=
2256 (map->type & BTRFS_BLOCK_GROUP_TYPE_MASK)) {
2257 btrfs_err(fs_info,
2258"chunk start=%llu len=%llu flags=0x%llx doesn't match block group start=%llu len=%llu flags=0x%llx",
2259 map->start, map->chunk_len,
2260 map->type & BTRFS_BLOCK_GROUP_TYPE_MASK,
2261 bg->start, bg->length,
2262 bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK);
2263 ret = -EUCLEAN;
2264 btrfs_free_chunk_map(map);
2265 btrfs_put_block_group(bg);
2266 break;
2267 }
2268 start = map->start + map->chunk_len;
2269 btrfs_free_chunk_map(map);
2270 btrfs_put_block_group(bg);
2271 }
2272 return ret;
2273}
2274
2275static int read_one_block_group(struct btrfs_fs_info *info,
2276 struct btrfs_block_group_item *bgi,
2277 const struct btrfs_key *key,
2278 int need_clear)
2279{
2280 struct btrfs_block_group *cache;
2281 const bool mixed = btrfs_fs_incompat(info, MIXED_GROUPS);
2282 int ret;
2283
2284 ASSERT(key->type == BTRFS_BLOCK_GROUP_ITEM_KEY);
2285
2286 cache = btrfs_create_block_group_cache(info, key->objectid);
2287 if (!cache)
2288 return -ENOMEM;
2289
2290 cache->length = key->offset;
2291 cache->used = btrfs_stack_block_group_used(bgi);
2292 cache->commit_used = cache->used;
2293 cache->flags = btrfs_stack_block_group_flags(bgi);
2294 cache->global_root_id = btrfs_stack_block_group_chunk_objectid(bgi);
2295
2296 set_free_space_tree_thresholds(cache);
2297
2298 if (need_clear) {
2299 /*
2300 * When we mount with old space cache, we need to
2301 * set BTRFS_DC_CLEAR and set dirty flag.
2302 *
2303 * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
2304 * truncate the old free space cache inode and
2305 * setup a new one.
2306 * b) Setting 'dirty flag' makes sure that we flush
2307 * the new space cache info onto disk.
2308 */
2309 if (btrfs_test_opt(info, SPACE_CACHE))
2310 cache->disk_cache_state = BTRFS_DC_CLEAR;
2311 }
2312 if (!mixed && ((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
2313 (cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
2314 btrfs_err(info,
2315"bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
2316 cache->start);
2317 ret = -EINVAL;
2318 goto error;
2319 }
2320
2321 ret = btrfs_load_block_group_zone_info(cache, false);
2322 if (ret) {
2323 btrfs_err(info, "zoned: failed to load zone info of bg %llu",
2324 cache->start);
2325 goto error;
2326 }
2327
2328 /*
2329 * We need to exclude the super stripes now so that the space info has
2330 * super bytes accounted for, otherwise we'll think we have more space
2331 * than we actually do.
2332 */
2333 ret = exclude_super_stripes(cache);
2334 if (ret) {
2335 /* We may have excluded something, so call this just in case. */
2336 btrfs_free_excluded_extents(cache);
2337 goto error;
2338 }
2339
2340 /*
2341 * For zoned filesystem, space after the allocation offset is the only
2342 * free space for a block group. So, we don't need any caching work.
2343 * btrfs_calc_zone_unusable() will set the amount of free space and
2344 * zone_unusable space.
2345 *
2346 * For regular filesystem, check for two cases, either we are full, and
2347 * therefore don't need to bother with the caching work since we won't
2348 * find any space, or we are empty, and we can just add all the space
2349 * in and be done with it. This saves us _a_lot_ of time, particularly
2350 * in the full case.
2351 */
2352 if (btrfs_is_zoned(info)) {
2353 btrfs_calc_zone_unusable(cache);
2354 /* Should not have any excluded extents. Just in case, though. */
2355 btrfs_free_excluded_extents(cache);
2356 } else if (cache->length == cache->used) {
2357 cache->cached = BTRFS_CACHE_FINISHED;
2358 btrfs_free_excluded_extents(cache);
2359 } else if (cache->used == 0) {
2360 cache->cached = BTRFS_CACHE_FINISHED;
2361 ret = btrfs_add_new_free_space(cache, cache->start,
2362 cache->start + cache->length, NULL);
2363 btrfs_free_excluded_extents(cache);
2364 if (ret)
2365 goto error;
2366 }
2367
2368 ret = btrfs_add_block_group_cache(info, cache);
2369 if (ret) {
2370 btrfs_remove_free_space_cache(cache);
2371 goto error;
2372 }
2373 trace_btrfs_add_block_group(info, cache, 0);
2374 btrfs_add_bg_to_space_info(info, cache);
2375
2376 set_avail_alloc_bits(info, cache->flags);
2377 if (btrfs_chunk_writeable(info, cache->start)) {
2378 if (cache->used == 0) {
2379 ASSERT(list_empty(&cache->bg_list));
2380 if (btrfs_test_opt(info, DISCARD_ASYNC))
2381 btrfs_discard_queue_work(&info->discard_ctl, cache);
2382 else
2383 btrfs_mark_bg_unused(cache);
2384 }
2385 } else {
2386 inc_block_group_ro(cache, 1);
2387 }
2388
2389 return 0;
2390error:
2391 btrfs_put_block_group(cache);
2392 return ret;
2393}
2394
2395static int fill_dummy_bgs(struct btrfs_fs_info *fs_info)
2396{
2397 struct rb_node *node;
2398 int ret = 0;
2399
2400 for (node = rb_first_cached(&fs_info->mapping_tree); node; node = rb_next(node)) {
2401 struct btrfs_chunk_map *map;
2402 struct btrfs_block_group *bg;
2403
2404 map = rb_entry(node, struct btrfs_chunk_map, rb_node);
2405 bg = btrfs_create_block_group_cache(fs_info, map->start);
2406 if (!bg) {
2407 ret = -ENOMEM;
2408 break;
2409 }
2410
2411 /* Fill dummy cache as FULL */
2412 bg->length = map->chunk_len;
2413 bg->flags = map->type;
2414 bg->cached = BTRFS_CACHE_FINISHED;
2415 bg->used = map->chunk_len;
2416 bg->flags = map->type;
2417 ret = btrfs_add_block_group_cache(fs_info, bg);
2418 /*
2419 * We may have some valid block group cache added already, in
2420 * that case we skip to the next one.
2421 */
2422 if (ret == -EEXIST) {
2423 ret = 0;
2424 btrfs_put_block_group(bg);
2425 continue;
2426 }
2427
2428 if (ret) {
2429 btrfs_remove_free_space_cache(bg);
2430 btrfs_put_block_group(bg);
2431 break;
2432 }
2433
2434 btrfs_add_bg_to_space_info(fs_info, bg);
2435
2436 set_avail_alloc_bits(fs_info, bg->flags);
2437 }
2438 if (!ret)
2439 btrfs_init_global_block_rsv(fs_info);
2440 return ret;
2441}
2442
2443int btrfs_read_block_groups(struct btrfs_fs_info *info)
2444{
2445 struct btrfs_root *root = btrfs_block_group_root(info);
2446 struct btrfs_path *path;
2447 int ret;
2448 struct btrfs_block_group *cache;
2449 struct btrfs_space_info *space_info;
2450 struct btrfs_key key;
2451 int need_clear = 0;
2452 u64 cache_gen;
2453
2454 /*
2455 * Either no extent root (with ibadroots rescue option) or we have
2456 * unsupported RO options. The fs can never be mounted read-write, so no
2457 * need to waste time searching block group items.
2458 *
2459 * This also allows new extent tree related changes to be RO compat,
2460 * no need for a full incompat flag.
2461 */
2462 if (!root || (btrfs_super_compat_ro_flags(info->super_copy) &
2463 ~BTRFS_FEATURE_COMPAT_RO_SUPP))
2464 return fill_dummy_bgs(info);
2465
2466 key.objectid = 0;
2467 key.offset = 0;
2468 key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
2469 path = btrfs_alloc_path();
2470 if (!path)
2471 return -ENOMEM;
2472
2473 cache_gen = btrfs_super_cache_generation(info->super_copy);
2474 if (btrfs_test_opt(info, SPACE_CACHE) &&
2475 btrfs_super_generation(info->super_copy) != cache_gen)
2476 need_clear = 1;
2477 if (btrfs_test_opt(info, CLEAR_CACHE))
2478 need_clear = 1;
2479
2480 while (1) {
2481 struct btrfs_block_group_item bgi;
2482 struct extent_buffer *leaf;
2483 int slot;
2484
2485 ret = find_first_block_group(info, path, &key);
2486 if (ret > 0)
2487 break;
2488 if (ret != 0)
2489 goto error;
2490
2491 leaf = path->nodes[0];
2492 slot = path->slots[0];
2493
2494 read_extent_buffer(leaf, &bgi, btrfs_item_ptr_offset(leaf, slot),
2495 sizeof(bgi));
2496
2497 btrfs_item_key_to_cpu(leaf, &key, slot);
2498 btrfs_release_path(path);
2499 ret = read_one_block_group(info, &bgi, &key, need_clear);
2500 if (ret < 0)
2501 goto error;
2502 key.objectid += key.offset;
2503 key.offset = 0;
2504 }
2505 btrfs_release_path(path);
2506
2507 list_for_each_entry(space_info, &info->space_info, list) {
2508 int i;
2509
2510 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2511 if (list_empty(&space_info->block_groups[i]))
2512 continue;
2513 cache = list_first_entry(&space_info->block_groups[i],
2514 struct btrfs_block_group,
2515 list);
2516 btrfs_sysfs_add_block_group_type(cache);
2517 }
2518
2519 if (!(btrfs_get_alloc_profile(info, space_info->flags) &
2520 (BTRFS_BLOCK_GROUP_RAID10 |
2521 BTRFS_BLOCK_GROUP_RAID1_MASK |
2522 BTRFS_BLOCK_GROUP_RAID56_MASK |
2523 BTRFS_BLOCK_GROUP_DUP)))
2524 continue;
2525 /*
2526 * Avoid allocating from un-mirrored block group if there are
2527 * mirrored block groups.
2528 */
2529 list_for_each_entry(cache,
2530 &space_info->block_groups[BTRFS_RAID_RAID0],
2531 list)
2532 inc_block_group_ro(cache, 1);
2533 list_for_each_entry(cache,
2534 &space_info->block_groups[BTRFS_RAID_SINGLE],
2535 list)
2536 inc_block_group_ro(cache, 1);
2537 }
2538
2539 btrfs_init_global_block_rsv(info);
2540 ret = check_chunk_block_group_mappings(info);
2541error:
2542 btrfs_free_path(path);
2543 /*
2544 * We've hit some error while reading the extent tree, and have
2545 * rescue=ibadroots mount option.
2546 * Try to fill the tree using dummy block groups so that the user can
2547 * continue to mount and grab their data.
2548 */
2549 if (ret && btrfs_test_opt(info, IGNOREBADROOTS))
2550 ret = fill_dummy_bgs(info);
2551 return ret;
2552}
2553
2554/*
2555 * This function, insert_block_group_item(), belongs to the phase 2 of chunk
2556 * allocation.
2557 *
2558 * See the comment at btrfs_chunk_alloc() for details about the chunk allocation
2559 * phases.
2560 */
2561static int insert_block_group_item(struct btrfs_trans_handle *trans,
2562 struct btrfs_block_group *block_group)
2563{
2564 struct btrfs_fs_info *fs_info = trans->fs_info;
2565 struct btrfs_block_group_item bgi;
2566 struct btrfs_root *root = btrfs_block_group_root(fs_info);
2567 struct btrfs_key key;
2568 u64 old_commit_used;
2569 int ret;
2570
2571 spin_lock(&block_group->lock);
2572 btrfs_set_stack_block_group_used(&bgi, block_group->used);
2573 btrfs_set_stack_block_group_chunk_objectid(&bgi,
2574 block_group->global_root_id);
2575 btrfs_set_stack_block_group_flags(&bgi, block_group->flags);
2576 old_commit_used = block_group->commit_used;
2577 block_group->commit_used = block_group->used;
2578 key.objectid = block_group->start;
2579 key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
2580 key.offset = block_group->length;
2581 spin_unlock(&block_group->lock);
2582
2583 ret = btrfs_insert_item(trans, root, &key, &bgi, sizeof(bgi));
2584 if (ret < 0) {
2585 spin_lock(&block_group->lock);
2586 block_group->commit_used = old_commit_used;
2587 spin_unlock(&block_group->lock);
2588 }
2589
2590 return ret;
2591}
2592
2593static int insert_dev_extent(struct btrfs_trans_handle *trans,
2594 struct btrfs_device *device, u64 chunk_offset,
2595 u64 start, u64 num_bytes)
2596{
2597 struct btrfs_fs_info *fs_info = device->fs_info;
2598 struct btrfs_root *root = fs_info->dev_root;
2599 struct btrfs_path *path;
2600 struct btrfs_dev_extent *extent;
2601 struct extent_buffer *leaf;
2602 struct btrfs_key key;
2603 int ret;
2604
2605 WARN_ON(!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state));
2606 WARN_ON(test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state));
2607 path = btrfs_alloc_path();
2608 if (!path)
2609 return -ENOMEM;
2610
2611 key.objectid = device->devid;
2612 key.type = BTRFS_DEV_EXTENT_KEY;
2613 key.offset = start;
2614 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*extent));
2615 if (ret)
2616 goto out;
2617
2618 leaf = path->nodes[0];
2619 extent = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_extent);
2620 btrfs_set_dev_extent_chunk_tree(leaf, extent, BTRFS_CHUNK_TREE_OBJECTID);
2621 btrfs_set_dev_extent_chunk_objectid(leaf, extent,
2622 BTRFS_FIRST_CHUNK_TREE_OBJECTID);
2623 btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
2624
2625 btrfs_set_dev_extent_length(leaf, extent, num_bytes);
2626 btrfs_mark_buffer_dirty(trans, leaf);
2627out:
2628 btrfs_free_path(path);
2629 return ret;
2630}
2631
2632/*
2633 * This function belongs to phase 2.
2634 *
2635 * See the comment at btrfs_chunk_alloc() for details about the chunk allocation
2636 * phases.
2637 */
2638static int insert_dev_extents(struct btrfs_trans_handle *trans,
2639 u64 chunk_offset, u64 chunk_size)
2640{
2641 struct btrfs_fs_info *fs_info = trans->fs_info;
2642 struct btrfs_device *device;
2643 struct btrfs_chunk_map *map;
2644 u64 dev_offset;
2645 int i;
2646 int ret = 0;
2647
2648 map = btrfs_get_chunk_map(fs_info, chunk_offset, chunk_size);
2649 if (IS_ERR(map))
2650 return PTR_ERR(map);
2651
2652 /*
2653 * Take the device list mutex to prevent races with the final phase of
2654 * a device replace operation that replaces the device object associated
2655 * with the map's stripes, because the device object's id can change
2656 * at any time during that final phase of the device replace operation
2657 * (dev-replace.c:btrfs_dev_replace_finishing()), so we could grab the
2658 * replaced device and then see it with an ID of BTRFS_DEV_REPLACE_DEVID,
2659 * resulting in persisting a device extent item with such ID.
2660 */
2661 mutex_lock(&fs_info->fs_devices->device_list_mutex);
2662 for (i = 0; i < map->num_stripes; i++) {
2663 device = map->stripes[i].dev;
2664 dev_offset = map->stripes[i].physical;
2665
2666 ret = insert_dev_extent(trans, device, chunk_offset, dev_offset,
2667 map->stripe_size);
2668 if (ret)
2669 break;
2670 }
2671 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2672
2673 btrfs_free_chunk_map(map);
2674 return ret;
2675}
2676
2677/*
2678 * This function, btrfs_create_pending_block_groups(), belongs to the phase 2 of
2679 * chunk allocation.
2680 *
2681 * See the comment at btrfs_chunk_alloc() for details about the chunk allocation
2682 * phases.
2683 */
2684void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans)
2685{
2686 struct btrfs_fs_info *fs_info = trans->fs_info;
2687 struct btrfs_block_group *block_group;
2688 int ret = 0;
2689
2690 while (!list_empty(&trans->new_bgs)) {
2691 int index;
2692
2693 block_group = list_first_entry(&trans->new_bgs,
2694 struct btrfs_block_group,
2695 bg_list);
2696 if (ret)
2697 goto next;
2698
2699 index = btrfs_bg_flags_to_raid_index(block_group->flags);
2700
2701 ret = insert_block_group_item(trans, block_group);
2702 if (ret)
2703 btrfs_abort_transaction(trans, ret);
2704 if (!test_bit(BLOCK_GROUP_FLAG_CHUNK_ITEM_INSERTED,
2705 &block_group->runtime_flags)) {
2706 mutex_lock(&fs_info->chunk_mutex);
2707 ret = btrfs_chunk_alloc_add_chunk_item(trans, block_group);
2708 mutex_unlock(&fs_info->chunk_mutex);
2709 if (ret)
2710 btrfs_abort_transaction(trans, ret);
2711 }
2712 ret = insert_dev_extents(trans, block_group->start,
2713 block_group->length);
2714 if (ret)
2715 btrfs_abort_transaction(trans, ret);
2716 add_block_group_free_space(trans, block_group);
2717
2718 /*
2719 * If we restriped during balance, we may have added a new raid
2720 * type, so now add the sysfs entries when it is safe to do so.
2721 * We don't have to worry about locking here as it's handled in
2722 * btrfs_sysfs_add_block_group_type.
2723 */
2724 if (block_group->space_info->block_group_kobjs[index] == NULL)
2725 btrfs_sysfs_add_block_group_type(block_group);
2726
2727 /* Already aborted the transaction if it failed. */
2728next:
2729 btrfs_dec_delayed_refs_rsv_bg_inserts(fs_info);
2730 list_del_init(&block_group->bg_list);
2731 clear_bit(BLOCK_GROUP_FLAG_NEW, &block_group->runtime_flags);
2732
2733 /*
2734 * If the block group is still unused, add it to the list of
2735 * unused block groups. The block group may have been created in
2736 * order to satisfy a space reservation, in which case the
2737 * extent allocation only happens later. But often we don't
2738 * actually need to allocate space that we previously reserved,
2739 * so the block group may become unused for a long time. For
2740 * example for metadata we generally reserve space for a worst
2741 * possible scenario, but then don't end up allocating all that
2742 * space or none at all (due to no need to COW, extent buffers
2743 * were already COWed in the current transaction and still
2744 * unwritten, tree heights lower than the maximum possible
2745 * height, etc). For data we generally reserve the axact amount
2746 * of space we are going to allocate later, the exception is
2747 * when using compression, as we must reserve space based on the
2748 * uncompressed data size, because the compression is only done
2749 * when writeback triggered and we don't know how much space we
2750 * are actually going to need, so we reserve the uncompressed
2751 * size because the data may be uncompressible in the worst case.
2752 */
2753 if (ret == 0) {
2754 bool used;
2755
2756 spin_lock(&block_group->lock);
2757 used = btrfs_is_block_group_used(block_group);
2758 spin_unlock(&block_group->lock);
2759
2760 if (!used)
2761 btrfs_mark_bg_unused(block_group);
2762 }
2763 }
2764 btrfs_trans_release_chunk_metadata(trans);
2765}
2766
2767/*
2768 * For extent tree v2 we use the block_group_item->chunk_offset to point at our
2769 * global root id. For v1 it's always set to BTRFS_FIRST_CHUNK_TREE_OBJECTID.
2770 */
2771static u64 calculate_global_root_id(struct btrfs_fs_info *fs_info, u64 offset)
2772{
2773 u64 div = SZ_1G;
2774 u64 index;
2775
2776 if (!btrfs_fs_incompat(fs_info, EXTENT_TREE_V2))
2777 return BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2778
2779 /* If we have a smaller fs index based on 128MiB. */
2780 if (btrfs_super_total_bytes(fs_info->super_copy) <= (SZ_1G * 10ULL))
2781 div = SZ_128M;
2782
2783 offset = div64_u64(offset, div);
2784 div64_u64_rem(offset, fs_info->nr_global_roots, &index);
2785 return index;
2786}
2787
2788struct btrfs_block_group *btrfs_make_block_group(struct btrfs_trans_handle *trans,
2789 u64 type,
2790 u64 chunk_offset, u64 size)
2791{
2792 struct btrfs_fs_info *fs_info = trans->fs_info;
2793 struct btrfs_block_group *cache;
2794 int ret;
2795
2796 btrfs_set_log_full_commit(trans);
2797
2798 cache = btrfs_create_block_group_cache(fs_info, chunk_offset);
2799 if (!cache)
2800 return ERR_PTR(-ENOMEM);
2801
2802 /*
2803 * Mark it as new before adding it to the rbtree of block groups or any
2804 * list, so that no other task finds it and calls btrfs_mark_bg_unused()
2805 * before the new flag is set.
2806 */
2807 set_bit(BLOCK_GROUP_FLAG_NEW, &cache->runtime_flags);
2808
2809 cache->length = size;
2810 set_free_space_tree_thresholds(cache);
2811 cache->flags = type;
2812 cache->cached = BTRFS_CACHE_FINISHED;
2813 cache->global_root_id = calculate_global_root_id(fs_info, cache->start);
2814
2815 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
2816 set_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &cache->runtime_flags);
2817
2818 ret = btrfs_load_block_group_zone_info(cache, true);
2819 if (ret) {
2820 btrfs_put_block_group(cache);
2821 return ERR_PTR(ret);
2822 }
2823
2824 ret = exclude_super_stripes(cache);
2825 if (ret) {
2826 /* We may have excluded something, so call this just in case */
2827 btrfs_free_excluded_extents(cache);
2828 btrfs_put_block_group(cache);
2829 return ERR_PTR(ret);
2830 }
2831
2832 ret = btrfs_add_new_free_space(cache, chunk_offset, chunk_offset + size, NULL);
2833 btrfs_free_excluded_extents(cache);
2834 if (ret) {
2835 btrfs_put_block_group(cache);
2836 return ERR_PTR(ret);
2837 }
2838
2839 /*
2840 * Ensure the corresponding space_info object is created and
2841 * assigned to our block group. We want our bg to be added to the rbtree
2842 * with its ->space_info set.
2843 */
2844 cache->space_info = btrfs_find_space_info(fs_info, cache->flags);
2845 ASSERT(cache->space_info);
2846
2847 ret = btrfs_add_block_group_cache(fs_info, cache);
2848 if (ret) {
2849 btrfs_remove_free_space_cache(cache);
2850 btrfs_put_block_group(cache);
2851 return ERR_PTR(ret);
2852 }
2853
2854 /*
2855 * Now that our block group has its ->space_info set and is inserted in
2856 * the rbtree, update the space info's counters.
2857 */
2858 trace_btrfs_add_block_group(fs_info, cache, 1);
2859 btrfs_add_bg_to_space_info(fs_info, cache);
2860 btrfs_update_global_block_rsv(fs_info);
2861
2862#ifdef CONFIG_BTRFS_DEBUG
2863 if (btrfs_should_fragment_free_space(cache)) {
2864 cache->space_info->bytes_used += size >> 1;
2865 fragment_free_space(cache);
2866 }
2867#endif
2868
2869 list_add_tail(&cache->bg_list, &trans->new_bgs);
2870 btrfs_inc_delayed_refs_rsv_bg_inserts(fs_info);
2871
2872 set_avail_alloc_bits(fs_info, type);
2873 return cache;
2874}
2875
2876/*
2877 * Mark one block group RO, can be called several times for the same block
2878 * group.
2879 *
2880 * @cache: the destination block group
2881 * @do_chunk_alloc: whether need to do chunk pre-allocation, this is to
2882 * ensure we still have some free space after marking this
2883 * block group RO.
2884 */
2885int btrfs_inc_block_group_ro(struct btrfs_block_group *cache,
2886 bool do_chunk_alloc)
2887{
2888 struct btrfs_fs_info *fs_info = cache->fs_info;
2889 struct btrfs_trans_handle *trans;
2890 struct btrfs_root *root = btrfs_block_group_root(fs_info);
2891 u64 alloc_flags;
2892 int ret;
2893 bool dirty_bg_running;
2894
2895 /*
2896 * This can only happen when we are doing read-only scrub on read-only
2897 * mount.
2898 * In that case we should not start a new transaction on read-only fs.
2899 * Thus here we skip all chunk allocations.
2900 */
2901 if (sb_rdonly(fs_info->sb)) {
2902 mutex_lock(&fs_info->ro_block_group_mutex);
2903 ret = inc_block_group_ro(cache, 0);
2904 mutex_unlock(&fs_info->ro_block_group_mutex);
2905 return ret;
2906 }
2907
2908 do {
2909 trans = btrfs_join_transaction(root);
2910 if (IS_ERR(trans))
2911 return PTR_ERR(trans);
2912
2913 dirty_bg_running = false;
2914
2915 /*
2916 * We're not allowed to set block groups readonly after the dirty
2917 * block group cache has started writing. If it already started,
2918 * back off and let this transaction commit.
2919 */
2920 mutex_lock(&fs_info->ro_block_group_mutex);
2921 if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
2922 u64 transid = trans->transid;
2923
2924 mutex_unlock(&fs_info->ro_block_group_mutex);
2925 btrfs_end_transaction(trans);
2926
2927 ret = btrfs_wait_for_commit(fs_info, transid);
2928 if (ret)
2929 return ret;
2930 dirty_bg_running = true;
2931 }
2932 } while (dirty_bg_running);
2933
2934 if (do_chunk_alloc) {
2935 /*
2936 * If we are changing raid levels, try to allocate a
2937 * corresponding block group with the new raid level.
2938 */
2939 alloc_flags = btrfs_get_alloc_profile(fs_info, cache->flags);
2940 if (alloc_flags != cache->flags) {
2941 ret = btrfs_chunk_alloc(trans, alloc_flags,
2942 CHUNK_ALLOC_FORCE);
2943 /*
2944 * ENOSPC is allowed here, we may have enough space
2945 * already allocated at the new raid level to carry on
2946 */
2947 if (ret == -ENOSPC)
2948 ret = 0;
2949 if (ret < 0)
2950 goto out;
2951 }
2952 }
2953
2954 ret = inc_block_group_ro(cache, 0);
2955 if (!ret)
2956 goto out;
2957 if (ret == -ETXTBSY)
2958 goto unlock_out;
2959
2960 /*
2961 * Skip chunk allocation if the bg is SYSTEM, this is to avoid system
2962 * chunk allocation storm to exhaust the system chunk array. Otherwise
2963 * we still want to try our best to mark the block group read-only.
2964 */
2965 if (!do_chunk_alloc && ret == -ENOSPC &&
2966 (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM))
2967 goto unlock_out;
2968
2969 alloc_flags = btrfs_get_alloc_profile(fs_info, cache->space_info->flags);
2970 ret = btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
2971 if (ret < 0)
2972 goto out;
2973 /*
2974 * We have allocated a new chunk. We also need to activate that chunk to
2975 * grant metadata tickets for zoned filesystem.
2976 */
2977 ret = btrfs_zoned_activate_one_bg(fs_info, cache->space_info, true);
2978 if (ret < 0)
2979 goto out;
2980
2981 ret = inc_block_group_ro(cache, 0);
2982 if (ret == -ETXTBSY)
2983 goto unlock_out;
2984out:
2985 if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
2986 alloc_flags = btrfs_get_alloc_profile(fs_info, cache->flags);
2987 mutex_lock(&fs_info->chunk_mutex);
2988 check_system_chunk(trans, alloc_flags);
2989 mutex_unlock(&fs_info->chunk_mutex);
2990 }
2991unlock_out:
2992 mutex_unlock(&fs_info->ro_block_group_mutex);
2993
2994 btrfs_end_transaction(trans);
2995 return ret;
2996}
2997
2998void btrfs_dec_block_group_ro(struct btrfs_block_group *cache)
2999{
3000 struct btrfs_space_info *sinfo = cache->space_info;
3001 u64 num_bytes;
3002
3003 BUG_ON(!cache->ro);
3004
3005 spin_lock(&sinfo->lock);
3006 spin_lock(&cache->lock);
3007 if (!--cache->ro) {
3008 if (btrfs_is_zoned(cache->fs_info)) {
3009 /* Migrate zone_unusable bytes back */
3010 cache->zone_unusable =
3011 (cache->alloc_offset - cache->used) +
3012 (cache->length - cache->zone_capacity);
3013 sinfo->bytes_zone_unusable += cache->zone_unusable;
3014 sinfo->bytes_readonly -= cache->zone_unusable;
3015 }
3016 num_bytes = cache->length - cache->reserved -
3017 cache->pinned - cache->bytes_super -
3018 cache->zone_unusable - cache->used;
3019 sinfo->bytes_readonly -= num_bytes;
3020 list_del_init(&cache->ro_list);
3021 }
3022 spin_unlock(&cache->lock);
3023 spin_unlock(&sinfo->lock);
3024}
3025
3026static int update_block_group_item(struct btrfs_trans_handle *trans,
3027 struct btrfs_path *path,
3028 struct btrfs_block_group *cache)
3029{
3030 struct btrfs_fs_info *fs_info = trans->fs_info;
3031 int ret;
3032 struct btrfs_root *root = btrfs_block_group_root(fs_info);
3033 unsigned long bi;
3034 struct extent_buffer *leaf;
3035 struct btrfs_block_group_item bgi;
3036 struct btrfs_key key;
3037 u64 old_commit_used;
3038 u64 used;
3039
3040 /*
3041 * Block group items update can be triggered out of commit transaction
3042 * critical section, thus we need a consistent view of used bytes.
3043 * We cannot use cache->used directly outside of the spin lock, as it
3044 * may be changed.
3045 */
3046 spin_lock(&cache->lock);
3047 old_commit_used = cache->commit_used;
3048 used = cache->used;
3049 /* No change in used bytes, can safely skip it. */
3050 if (cache->commit_used == used) {
3051 spin_unlock(&cache->lock);
3052 return 0;
3053 }
3054 cache->commit_used = used;
3055 spin_unlock(&cache->lock);
3056
3057 key.objectid = cache->start;
3058 key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
3059 key.offset = cache->length;
3060
3061 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
3062 if (ret) {
3063 if (ret > 0)
3064 ret = -ENOENT;
3065 goto fail;
3066 }
3067
3068 leaf = path->nodes[0];
3069 bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3070 btrfs_set_stack_block_group_used(&bgi, used);
3071 btrfs_set_stack_block_group_chunk_objectid(&bgi,
3072 cache->global_root_id);
3073 btrfs_set_stack_block_group_flags(&bgi, cache->flags);
3074 write_extent_buffer(leaf, &bgi, bi, sizeof(bgi));
3075 btrfs_mark_buffer_dirty(trans, leaf);
3076fail:
3077 btrfs_release_path(path);
3078 /*
3079 * We didn't update the block group item, need to revert commit_used
3080 * unless the block group item didn't exist yet - this is to prevent a
3081 * race with a concurrent insertion of the block group item, with
3082 * insert_block_group_item(), that happened just after we attempted to
3083 * update. In that case we would reset commit_used to 0 just after the
3084 * insertion set it to a value greater than 0 - if the block group later
3085 * becomes with 0 used bytes, we would incorrectly skip its update.
3086 */
3087 if (ret < 0 && ret != -ENOENT) {
3088 spin_lock(&cache->lock);
3089 cache->commit_used = old_commit_used;
3090 spin_unlock(&cache->lock);
3091 }
3092 return ret;
3093
3094}
3095
3096static int cache_save_setup(struct btrfs_block_group *block_group,
3097 struct btrfs_trans_handle *trans,
3098 struct btrfs_path *path)
3099{
3100 struct btrfs_fs_info *fs_info = block_group->fs_info;
3101 struct inode *inode = NULL;
3102 struct extent_changeset *data_reserved = NULL;
3103 u64 alloc_hint = 0;
3104 int dcs = BTRFS_DC_ERROR;
3105 u64 cache_size = 0;
3106 int retries = 0;
3107 int ret = 0;
3108
3109 if (!btrfs_test_opt(fs_info, SPACE_CACHE))
3110 return 0;
3111
3112 /*
3113 * If this block group is smaller than 100 megs don't bother caching the
3114 * block group.
3115 */
3116 if (block_group->length < (100 * SZ_1M)) {
3117 spin_lock(&block_group->lock);
3118 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3119 spin_unlock(&block_group->lock);
3120 return 0;
3121 }
3122
3123 if (TRANS_ABORTED(trans))
3124 return 0;
3125again:
3126 inode = lookup_free_space_inode(block_group, path);
3127 if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3128 ret = PTR_ERR(inode);
3129 btrfs_release_path(path);
3130 goto out;
3131 }
3132
3133 if (IS_ERR(inode)) {
3134 BUG_ON(retries);
3135 retries++;
3136
3137 if (block_group->ro)
3138 goto out_free;
3139
3140 ret = create_free_space_inode(trans, block_group, path);
3141 if (ret)
3142 goto out_free;
3143 goto again;
3144 }
3145
3146 /*
3147 * We want to set the generation to 0, that way if anything goes wrong
3148 * from here on out we know not to trust this cache when we load up next
3149 * time.
3150 */
3151 BTRFS_I(inode)->generation = 0;
3152 ret = btrfs_update_inode(trans, BTRFS_I(inode));
3153 if (ret) {
3154 /*
3155 * So theoretically we could recover from this, simply set the
3156 * super cache generation to 0 so we know to invalidate the
3157 * cache, but then we'd have to keep track of the block groups
3158 * that fail this way so we know we _have_ to reset this cache
3159 * before the next commit or risk reading stale cache. So to
3160 * limit our exposure to horrible edge cases lets just abort the
3161 * transaction, this only happens in really bad situations
3162 * anyway.
3163 */
3164 btrfs_abort_transaction(trans, ret);
3165 goto out_put;
3166 }
3167 WARN_ON(ret);
3168
3169 /* We've already setup this transaction, go ahead and exit */
3170 if (block_group->cache_generation == trans->transid &&
3171 i_size_read(inode)) {
3172 dcs = BTRFS_DC_SETUP;
3173 goto out_put;
3174 }
3175
3176 if (i_size_read(inode) > 0) {
3177 ret = btrfs_check_trunc_cache_free_space(fs_info,
3178 &fs_info->global_block_rsv);
3179 if (ret)
3180 goto out_put;
3181
3182 ret = btrfs_truncate_free_space_cache(trans, NULL, inode);
3183 if (ret)
3184 goto out_put;
3185 }
3186
3187 spin_lock(&block_group->lock);
3188 if (block_group->cached != BTRFS_CACHE_FINISHED ||
3189 !btrfs_test_opt(fs_info, SPACE_CACHE)) {
3190 /*
3191 * don't bother trying to write stuff out _if_
3192 * a) we're not cached,
3193 * b) we're with nospace_cache mount option,
3194 * c) we're with v2 space_cache (FREE_SPACE_TREE).
3195 */
3196 dcs = BTRFS_DC_WRITTEN;
3197 spin_unlock(&block_group->lock);
3198 goto out_put;
3199 }
3200 spin_unlock(&block_group->lock);
3201
3202 /*
3203 * We hit an ENOSPC when setting up the cache in this transaction, just
3204 * skip doing the setup, we've already cleared the cache so we're safe.
3205 */
3206 if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
3207 ret = -ENOSPC;
3208 goto out_put;
3209 }
3210
3211 /*
3212 * Try to preallocate enough space based on how big the block group is.
3213 * Keep in mind this has to include any pinned space which could end up
3214 * taking up quite a bit since it's not folded into the other space
3215 * cache.
3216 */
3217 cache_size = div_u64(block_group->length, SZ_256M);
3218 if (!cache_size)
3219 cache_size = 1;
3220
3221 cache_size *= 16;
3222 cache_size *= fs_info->sectorsize;
3223
3224 ret = btrfs_check_data_free_space(BTRFS_I(inode), &data_reserved, 0,
3225 cache_size, false);
3226 if (ret)
3227 goto out_put;
3228
3229 ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, cache_size,
3230 cache_size, cache_size,
3231 &alloc_hint);
3232 /*
3233 * Our cache requires contiguous chunks so that we don't modify a bunch
3234 * of metadata or split extents when writing the cache out, which means
3235 * we can enospc if we are heavily fragmented in addition to just normal
3236 * out of space conditions. So if we hit this just skip setting up any
3237 * other block groups for this transaction, maybe we'll unpin enough
3238 * space the next time around.
3239 */
3240 if (!ret)
3241 dcs = BTRFS_DC_SETUP;
3242 else if (ret == -ENOSPC)
3243 set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
3244
3245out_put:
3246 iput(inode);
3247out_free:
3248 btrfs_release_path(path);
3249out:
3250 spin_lock(&block_group->lock);
3251 if (!ret && dcs == BTRFS_DC_SETUP)
3252 block_group->cache_generation = trans->transid;
3253 block_group->disk_cache_state = dcs;
3254 spin_unlock(&block_group->lock);
3255
3256 extent_changeset_free(data_reserved);
3257 return ret;
3258}
3259
3260int btrfs_setup_space_cache(struct btrfs_trans_handle *trans)
3261{
3262 struct btrfs_fs_info *fs_info = trans->fs_info;
3263 struct btrfs_block_group *cache, *tmp;
3264 struct btrfs_transaction *cur_trans = trans->transaction;
3265 struct btrfs_path *path;
3266
3267 if (list_empty(&cur_trans->dirty_bgs) ||
3268 !btrfs_test_opt(fs_info, SPACE_CACHE))
3269 return 0;
3270
3271 path = btrfs_alloc_path();
3272 if (!path)
3273 return -ENOMEM;
3274
3275 /* Could add new block groups, use _safe just in case */
3276 list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
3277 dirty_list) {
3278 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3279 cache_save_setup(cache, trans, path);
3280 }
3281
3282 btrfs_free_path(path);
3283 return 0;
3284}
3285
3286/*
3287 * Transaction commit does final block group cache writeback during a critical
3288 * section where nothing is allowed to change the FS. This is required in
3289 * order for the cache to actually match the block group, but can introduce a
3290 * lot of latency into the commit.
3291 *
3292 * So, btrfs_start_dirty_block_groups is here to kick off block group cache IO.
3293 * There's a chance we'll have to redo some of it if the block group changes
3294 * again during the commit, but it greatly reduces the commit latency by
3295 * getting rid of the easy block groups while we're still allowing others to
3296 * join the commit.
3297 */
3298int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans)
3299{
3300 struct btrfs_fs_info *fs_info = trans->fs_info;
3301 struct btrfs_block_group *cache;
3302 struct btrfs_transaction *cur_trans = trans->transaction;
3303 int ret = 0;
3304 int should_put;
3305 struct btrfs_path *path = NULL;
3306 LIST_HEAD(dirty);
3307 struct list_head *io = &cur_trans->io_bgs;
3308 int loops = 0;
3309
3310 spin_lock(&cur_trans->dirty_bgs_lock);
3311 if (list_empty(&cur_trans->dirty_bgs)) {
3312 spin_unlock(&cur_trans->dirty_bgs_lock);
3313 return 0;
3314 }
3315 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3316 spin_unlock(&cur_trans->dirty_bgs_lock);
3317
3318again:
3319 /* Make sure all the block groups on our dirty list actually exist */
3320 btrfs_create_pending_block_groups(trans);
3321
3322 if (!path) {
3323 path = btrfs_alloc_path();
3324 if (!path) {
3325 ret = -ENOMEM;
3326 goto out;
3327 }
3328 }
3329
3330 /*
3331 * cache_write_mutex is here only to save us from balance or automatic
3332 * removal of empty block groups deleting this block group while we are
3333 * writing out the cache
3334 */
3335 mutex_lock(&trans->transaction->cache_write_mutex);
3336 while (!list_empty(&dirty)) {
3337 bool drop_reserve = true;
3338
3339 cache = list_first_entry(&dirty, struct btrfs_block_group,
3340 dirty_list);
3341 /*
3342 * This can happen if something re-dirties a block group that
3343 * is already under IO. Just wait for it to finish and then do
3344 * it all again
3345 */
3346 if (!list_empty(&cache->io_list)) {
3347 list_del_init(&cache->io_list);
3348 btrfs_wait_cache_io(trans, cache, path);
3349 btrfs_put_block_group(cache);
3350 }
3351
3352
3353 /*
3354 * btrfs_wait_cache_io uses the cache->dirty_list to decide if
3355 * it should update the cache_state. Don't delete until after
3356 * we wait.
3357 *
3358 * Since we're not running in the commit critical section
3359 * we need the dirty_bgs_lock to protect from update_block_group
3360 */
3361 spin_lock(&cur_trans->dirty_bgs_lock);
3362 list_del_init(&cache->dirty_list);
3363 spin_unlock(&cur_trans->dirty_bgs_lock);
3364
3365 should_put = 1;
3366
3367 cache_save_setup(cache, trans, path);
3368
3369 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
3370 cache->io_ctl.inode = NULL;
3371 ret = btrfs_write_out_cache(trans, cache, path);
3372 if (ret == 0 && cache->io_ctl.inode) {
3373 should_put = 0;
3374
3375 /*
3376 * The cache_write_mutex is protecting the
3377 * io_list, also refer to the definition of
3378 * btrfs_transaction::io_bgs for more details
3379 */
3380 list_add_tail(&cache->io_list, io);
3381 } else {
3382 /*
3383 * If we failed to write the cache, the
3384 * generation will be bad and life goes on
3385 */
3386 ret = 0;
3387 }
3388 }
3389 if (!ret) {
3390 ret = update_block_group_item(trans, path, cache);
3391 /*
3392 * Our block group might still be attached to the list
3393 * of new block groups in the transaction handle of some
3394 * other task (struct btrfs_trans_handle->new_bgs). This
3395 * means its block group item isn't yet in the extent
3396 * tree. If this happens ignore the error, as we will
3397 * try again later in the critical section of the
3398 * transaction commit.
3399 */
3400 if (ret == -ENOENT) {
3401 ret = 0;
3402 spin_lock(&cur_trans->dirty_bgs_lock);
3403 if (list_empty(&cache->dirty_list)) {
3404 list_add_tail(&cache->dirty_list,
3405 &cur_trans->dirty_bgs);
3406 btrfs_get_block_group(cache);
3407 drop_reserve = false;
3408 }
3409 spin_unlock(&cur_trans->dirty_bgs_lock);
3410 } else if (ret) {
3411 btrfs_abort_transaction(trans, ret);
3412 }
3413 }
3414
3415 /* If it's not on the io list, we need to put the block group */
3416 if (should_put)
3417 btrfs_put_block_group(cache);
3418 if (drop_reserve)
3419 btrfs_dec_delayed_refs_rsv_bg_updates(fs_info);
3420 /*
3421 * Avoid blocking other tasks for too long. It might even save
3422 * us from writing caches for block groups that are going to be
3423 * removed.
3424 */
3425 mutex_unlock(&trans->transaction->cache_write_mutex);
3426 if (ret)
3427 goto out;
3428 mutex_lock(&trans->transaction->cache_write_mutex);
3429 }
3430 mutex_unlock(&trans->transaction->cache_write_mutex);
3431
3432 /*
3433 * Go through delayed refs for all the stuff we've just kicked off
3434 * and then loop back (just once)
3435 */
3436 if (!ret)
3437 ret = btrfs_run_delayed_refs(trans, 0);
3438 if (!ret && loops == 0) {
3439 loops++;
3440 spin_lock(&cur_trans->dirty_bgs_lock);
3441 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3442 /*
3443 * dirty_bgs_lock protects us from concurrent block group
3444 * deletes too (not just cache_write_mutex).
3445 */
3446 if (!list_empty(&dirty)) {
3447 spin_unlock(&cur_trans->dirty_bgs_lock);
3448 goto again;
3449 }
3450 spin_unlock(&cur_trans->dirty_bgs_lock);
3451 }
3452out:
3453 if (ret < 0) {
3454 spin_lock(&cur_trans->dirty_bgs_lock);
3455 list_splice_init(&dirty, &cur_trans->dirty_bgs);
3456 spin_unlock(&cur_trans->dirty_bgs_lock);
3457 btrfs_cleanup_dirty_bgs(cur_trans, fs_info);
3458 }
3459
3460 btrfs_free_path(path);
3461 return ret;
3462}
3463
3464int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans)
3465{
3466 struct btrfs_fs_info *fs_info = trans->fs_info;
3467 struct btrfs_block_group *cache;
3468 struct btrfs_transaction *cur_trans = trans->transaction;
3469 int ret = 0;
3470 int should_put;
3471 struct btrfs_path *path;
3472 struct list_head *io = &cur_trans->io_bgs;
3473
3474 path = btrfs_alloc_path();
3475 if (!path)
3476 return -ENOMEM;
3477
3478 /*
3479 * Even though we are in the critical section of the transaction commit,
3480 * we can still have concurrent tasks adding elements to this
3481 * transaction's list of dirty block groups. These tasks correspond to
3482 * endio free space workers started when writeback finishes for a
3483 * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
3484 * allocate new block groups as a result of COWing nodes of the root
3485 * tree when updating the free space inode. The writeback for the space
3486 * caches is triggered by an earlier call to
3487 * btrfs_start_dirty_block_groups() and iterations of the following
3488 * loop.
3489 * Also we want to do the cache_save_setup first and then run the
3490 * delayed refs to make sure we have the best chance at doing this all
3491 * in one shot.
3492 */
3493 spin_lock(&cur_trans->dirty_bgs_lock);
3494 while (!list_empty(&cur_trans->dirty_bgs)) {
3495 cache = list_first_entry(&cur_trans->dirty_bgs,
3496 struct btrfs_block_group,
3497 dirty_list);
3498
3499 /*
3500 * This can happen if cache_save_setup re-dirties a block group
3501 * that is already under IO. Just wait for it to finish and
3502 * then do it all again
3503 */
3504 if (!list_empty(&cache->io_list)) {
3505 spin_unlock(&cur_trans->dirty_bgs_lock);
3506 list_del_init(&cache->io_list);
3507 btrfs_wait_cache_io(trans, cache, path);
3508 btrfs_put_block_group(cache);
3509 spin_lock(&cur_trans->dirty_bgs_lock);
3510 }
3511
3512 /*
3513 * Don't remove from the dirty list until after we've waited on
3514 * any pending IO
3515 */
3516 list_del_init(&cache->dirty_list);
3517 spin_unlock(&cur_trans->dirty_bgs_lock);
3518 should_put = 1;
3519
3520 cache_save_setup(cache, trans, path);
3521
3522 if (!ret)
3523 ret = btrfs_run_delayed_refs(trans, U64_MAX);
3524
3525 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
3526 cache->io_ctl.inode = NULL;
3527 ret = btrfs_write_out_cache(trans, cache, path);
3528 if (ret == 0 && cache->io_ctl.inode) {
3529 should_put = 0;
3530 list_add_tail(&cache->io_list, io);
3531 } else {
3532 /*
3533 * If we failed to write the cache, the
3534 * generation will be bad and life goes on
3535 */
3536 ret = 0;
3537 }
3538 }
3539 if (!ret) {
3540 ret = update_block_group_item(trans, path, cache);
3541 /*
3542 * One of the free space endio workers might have
3543 * created a new block group while updating a free space
3544 * cache's inode (at inode.c:btrfs_finish_ordered_io())
3545 * and hasn't released its transaction handle yet, in
3546 * which case the new block group is still attached to
3547 * its transaction handle and its creation has not
3548 * finished yet (no block group item in the extent tree
3549 * yet, etc). If this is the case, wait for all free
3550 * space endio workers to finish and retry. This is a
3551 * very rare case so no need for a more efficient and
3552 * complex approach.
3553 */
3554 if (ret == -ENOENT) {
3555 wait_event(cur_trans->writer_wait,
3556 atomic_read(&cur_trans->num_writers) == 1);
3557 ret = update_block_group_item(trans, path, cache);
3558 }
3559 if (ret)
3560 btrfs_abort_transaction(trans, ret);
3561 }
3562
3563 /* If its not on the io list, we need to put the block group */
3564 if (should_put)
3565 btrfs_put_block_group(cache);
3566 btrfs_dec_delayed_refs_rsv_bg_updates(fs_info);
3567 spin_lock(&cur_trans->dirty_bgs_lock);
3568 }
3569 spin_unlock(&cur_trans->dirty_bgs_lock);
3570
3571 /*
3572 * Refer to the definition of io_bgs member for details why it's safe
3573 * to use it without any locking
3574 */
3575 while (!list_empty(io)) {
3576 cache = list_first_entry(io, struct btrfs_block_group,
3577 io_list);
3578 list_del_init(&cache->io_list);
3579 btrfs_wait_cache_io(trans, cache, path);
3580 btrfs_put_block_group(cache);
3581 }
3582
3583 btrfs_free_path(path);
3584 return ret;
3585}
3586
3587int btrfs_update_block_group(struct btrfs_trans_handle *trans,
3588 u64 bytenr, u64 num_bytes, bool alloc)
3589{
3590 struct btrfs_fs_info *info = trans->fs_info;
3591 struct btrfs_space_info *space_info;
3592 struct btrfs_block_group *cache;
3593 u64 old_val;
3594 bool reclaim = false;
3595 bool bg_already_dirty = true;
3596 int factor;
3597
3598 /* Block accounting for super block */
3599 spin_lock(&info->delalloc_root_lock);
3600 old_val = btrfs_super_bytes_used(info->super_copy);
3601 if (alloc)
3602 old_val += num_bytes;
3603 else
3604 old_val -= num_bytes;
3605 btrfs_set_super_bytes_used(info->super_copy, old_val);
3606 spin_unlock(&info->delalloc_root_lock);
3607
3608 cache = btrfs_lookup_block_group(info, bytenr);
3609 if (!cache)
3610 return -ENOENT;
3611
3612 /* An extent can not span multiple block groups. */
3613 ASSERT(bytenr + num_bytes <= cache->start + cache->length);
3614
3615 space_info = cache->space_info;
3616 factor = btrfs_bg_type_to_factor(cache->flags);
3617
3618 /*
3619 * If this block group has free space cache written out, we need to make
3620 * sure to load it if we are removing space. This is because we need
3621 * the unpinning stage to actually add the space back to the block group,
3622 * otherwise we will leak space.
3623 */
3624 if (!alloc && !btrfs_block_group_done(cache))
3625 btrfs_cache_block_group(cache, true);
3626
3627 spin_lock(&space_info->lock);
3628 spin_lock(&cache->lock);
3629
3630 if (btrfs_test_opt(info, SPACE_CACHE) &&
3631 cache->disk_cache_state < BTRFS_DC_CLEAR)
3632 cache->disk_cache_state = BTRFS_DC_CLEAR;
3633
3634 old_val = cache->used;
3635 if (alloc) {
3636 old_val += num_bytes;
3637 cache->used = old_val;
3638 cache->reserved -= num_bytes;
3639 space_info->bytes_reserved -= num_bytes;
3640 space_info->bytes_used += num_bytes;
3641 space_info->disk_used += num_bytes * factor;
3642 spin_unlock(&cache->lock);
3643 spin_unlock(&space_info->lock);
3644 } else {
3645 old_val -= num_bytes;
3646 cache->used = old_val;
3647 cache->pinned += num_bytes;
3648 btrfs_space_info_update_bytes_pinned(info, space_info, num_bytes);
3649 space_info->bytes_used -= num_bytes;
3650 space_info->disk_used -= num_bytes * factor;
3651
3652 reclaim = should_reclaim_block_group(cache, num_bytes);
3653
3654 spin_unlock(&cache->lock);
3655 spin_unlock(&space_info->lock);
3656
3657 set_extent_bit(&trans->transaction->pinned_extents, bytenr,
3658 bytenr + num_bytes - 1, EXTENT_DIRTY, NULL);
3659 }
3660
3661 spin_lock(&trans->transaction->dirty_bgs_lock);
3662 if (list_empty(&cache->dirty_list)) {
3663 list_add_tail(&cache->dirty_list, &trans->transaction->dirty_bgs);
3664 bg_already_dirty = false;
3665 btrfs_get_block_group(cache);
3666 }
3667 spin_unlock(&trans->transaction->dirty_bgs_lock);
3668
3669 /*
3670 * No longer have used bytes in this block group, queue it for deletion.
3671 * We do this after adding the block group to the dirty list to avoid
3672 * races between cleaner kthread and space cache writeout.
3673 */
3674 if (!alloc && old_val == 0) {
3675 if (!btrfs_test_opt(info, DISCARD_ASYNC))
3676 btrfs_mark_bg_unused(cache);
3677 } else if (!alloc && reclaim) {
3678 btrfs_mark_bg_to_reclaim(cache);
3679 }
3680
3681 btrfs_put_block_group(cache);
3682
3683 /* Modified block groups are accounted for in the delayed_refs_rsv. */
3684 if (!bg_already_dirty)
3685 btrfs_inc_delayed_refs_rsv_bg_updates(info);
3686
3687 return 0;
3688}
3689
3690/*
3691 * Update the block_group and space info counters.
3692 *
3693 * @cache: The cache we are manipulating
3694 * @ram_bytes: The number of bytes of file content, and will be same to
3695 * @num_bytes except for the compress path.
3696 * @num_bytes: The number of bytes in question
3697 * @delalloc: The blocks are allocated for the delalloc write
3698 *
3699 * This is called by the allocator when it reserves space. If this is a
3700 * reservation and the block group has become read only we cannot make the
3701 * reservation and return -EAGAIN, otherwise this function always succeeds.
3702 */
3703int btrfs_add_reserved_bytes(struct btrfs_block_group *cache,
3704 u64 ram_bytes, u64 num_bytes, int delalloc,
3705 bool force_wrong_size_class)
3706{
3707 struct btrfs_space_info *space_info = cache->space_info;
3708 enum btrfs_block_group_size_class size_class;
3709 int ret = 0;
3710
3711 spin_lock(&space_info->lock);
3712 spin_lock(&cache->lock);
3713 if (cache->ro) {
3714 ret = -EAGAIN;
3715 goto out;
3716 }
3717
3718 if (btrfs_block_group_should_use_size_class(cache)) {
3719 size_class = btrfs_calc_block_group_size_class(num_bytes);
3720 ret = btrfs_use_block_group_size_class(cache, size_class, force_wrong_size_class);
3721 if (ret)
3722 goto out;
3723 }
3724 cache->reserved += num_bytes;
3725 space_info->bytes_reserved += num_bytes;
3726 trace_btrfs_space_reservation(cache->fs_info, "space_info",
3727 space_info->flags, num_bytes, 1);
3728 btrfs_space_info_update_bytes_may_use(cache->fs_info,
3729 space_info, -ram_bytes);
3730 if (delalloc)
3731 cache->delalloc_bytes += num_bytes;
3732
3733 /*
3734 * Compression can use less space than we reserved, so wake tickets if
3735 * that happens.
3736 */
3737 if (num_bytes < ram_bytes)
3738 btrfs_try_granting_tickets(cache->fs_info, space_info);
3739out:
3740 spin_unlock(&cache->lock);
3741 spin_unlock(&space_info->lock);
3742 return ret;
3743}
3744
3745/*
3746 * Update the block_group and space info counters.
3747 *
3748 * @cache: The cache we are manipulating
3749 * @num_bytes: The number of bytes in question
3750 * @delalloc: The blocks are allocated for the delalloc write
3751 *
3752 * This is called by somebody who is freeing space that was never actually used
3753 * on disk. For example if you reserve some space for a new leaf in transaction
3754 * A and before transaction A commits you free that leaf, you call this with
3755 * reserve set to 0 in order to clear the reservation.
3756 */
3757void btrfs_free_reserved_bytes(struct btrfs_block_group *cache,
3758 u64 num_bytes, int delalloc)
3759{
3760 struct btrfs_space_info *space_info = cache->space_info;
3761
3762 spin_lock(&space_info->lock);
3763 spin_lock(&cache->lock);
3764 if (cache->ro)
3765 space_info->bytes_readonly += num_bytes;
3766 cache->reserved -= num_bytes;
3767 space_info->bytes_reserved -= num_bytes;
3768 space_info->max_extent_size = 0;
3769
3770 if (delalloc)
3771 cache->delalloc_bytes -= num_bytes;
3772 spin_unlock(&cache->lock);
3773
3774 btrfs_try_granting_tickets(cache->fs_info, space_info);
3775 spin_unlock(&space_info->lock);
3776}
3777
3778static void force_metadata_allocation(struct btrfs_fs_info *info)
3779{
3780 struct list_head *head = &info->space_info;
3781 struct btrfs_space_info *found;
3782
3783 list_for_each_entry(found, head, list) {
3784 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3785 found->force_alloc = CHUNK_ALLOC_FORCE;
3786 }
3787}
3788
3789static int should_alloc_chunk(struct btrfs_fs_info *fs_info,
3790 struct btrfs_space_info *sinfo, int force)
3791{
3792 u64 bytes_used = btrfs_space_info_used(sinfo, false);
3793 u64 thresh;
3794
3795 if (force == CHUNK_ALLOC_FORCE)
3796 return 1;
3797
3798 /*
3799 * in limited mode, we want to have some free space up to
3800 * about 1% of the FS size.
3801 */
3802 if (force == CHUNK_ALLOC_LIMITED) {
3803 thresh = btrfs_super_total_bytes(fs_info->super_copy);
3804 thresh = max_t(u64, SZ_64M, mult_perc(thresh, 1));
3805
3806 if (sinfo->total_bytes - bytes_used < thresh)
3807 return 1;
3808 }
3809
3810 if (bytes_used + SZ_2M < mult_perc(sinfo->total_bytes, 80))
3811 return 0;
3812 return 1;
3813}
3814
3815int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans, u64 type)
3816{
3817 u64 alloc_flags = btrfs_get_alloc_profile(trans->fs_info, type);
3818
3819 return btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
3820}
3821
3822static struct btrfs_block_group *do_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags)
3823{
3824 struct btrfs_block_group *bg;
3825 int ret;
3826
3827 /*
3828 * Check if we have enough space in the system space info because we
3829 * will need to update device items in the chunk btree and insert a new
3830 * chunk item in the chunk btree as well. This will allocate a new
3831 * system block group if needed.
3832 */
3833 check_system_chunk(trans, flags);
3834
3835 bg = btrfs_create_chunk(trans, flags);
3836 if (IS_ERR(bg)) {
3837 ret = PTR_ERR(bg);
3838 goto out;
3839 }
3840
3841 ret = btrfs_chunk_alloc_add_chunk_item(trans, bg);
3842 /*
3843 * Normally we are not expected to fail with -ENOSPC here, since we have
3844 * previously reserved space in the system space_info and allocated one
3845 * new system chunk if necessary. However there are three exceptions:
3846 *
3847 * 1) We may have enough free space in the system space_info but all the
3848 * existing system block groups have a profile which can not be used
3849 * for extent allocation.
3850 *
3851 * This happens when mounting in degraded mode. For example we have a
3852 * RAID1 filesystem with 2 devices, lose one device and mount the fs
3853 * using the other device in degraded mode. If we then allocate a chunk,
3854 * we may have enough free space in the existing system space_info, but
3855 * none of the block groups can be used for extent allocation since they
3856 * have a RAID1 profile, and because we are in degraded mode with a
3857 * single device, we are forced to allocate a new system chunk with a
3858 * SINGLE profile. Making check_system_chunk() iterate over all system
3859 * block groups and check if they have a usable profile and enough space
3860 * can be slow on very large filesystems, so we tolerate the -ENOSPC and
3861 * try again after forcing allocation of a new system chunk. Like this
3862 * we avoid paying the cost of that search in normal circumstances, when
3863 * we were not mounted in degraded mode;
3864 *
3865 * 2) We had enough free space info the system space_info, and one suitable
3866 * block group to allocate from when we called check_system_chunk()
3867 * above. However right after we called it, the only system block group
3868 * with enough free space got turned into RO mode by a running scrub,
3869 * and in this case we have to allocate a new one and retry. We only
3870 * need do this allocate and retry once, since we have a transaction
3871 * handle and scrub uses the commit root to search for block groups;
3872 *
3873 * 3) We had one system block group with enough free space when we called
3874 * check_system_chunk(), but after that, right before we tried to
3875 * allocate the last extent buffer we needed, a discard operation came
3876 * in and it temporarily removed the last free space entry from the
3877 * block group (discard removes a free space entry, discards it, and
3878 * then adds back the entry to the block group cache).
3879 */
3880 if (ret == -ENOSPC) {
3881 const u64 sys_flags = btrfs_system_alloc_profile(trans->fs_info);
3882 struct btrfs_block_group *sys_bg;
3883
3884 sys_bg = btrfs_create_chunk(trans, sys_flags);
3885 if (IS_ERR(sys_bg)) {
3886 ret = PTR_ERR(sys_bg);
3887 btrfs_abort_transaction(trans, ret);
3888 goto out;
3889 }
3890
3891 ret = btrfs_chunk_alloc_add_chunk_item(trans, sys_bg);
3892 if (ret) {
3893 btrfs_abort_transaction(trans, ret);
3894 goto out;
3895 }
3896
3897 ret = btrfs_chunk_alloc_add_chunk_item(trans, bg);
3898 if (ret) {
3899 btrfs_abort_transaction(trans, ret);
3900 goto out;
3901 }
3902 } else if (ret) {
3903 btrfs_abort_transaction(trans, ret);
3904 goto out;
3905 }
3906out:
3907 btrfs_trans_release_chunk_metadata(trans);
3908
3909 if (ret)
3910 return ERR_PTR(ret);
3911
3912 btrfs_get_block_group(bg);
3913 return bg;
3914}
3915
3916/*
3917 * Chunk allocation is done in 2 phases:
3918 *
3919 * 1) Phase 1 - through btrfs_chunk_alloc() we allocate device extents for
3920 * the chunk, the chunk mapping, create its block group and add the items
3921 * that belong in the chunk btree to it - more specifically, we need to
3922 * update device items in the chunk btree and add a new chunk item to it.
3923 *
3924 * 2) Phase 2 - through btrfs_create_pending_block_groups(), we add the block
3925 * group item to the extent btree and the device extent items to the devices
3926 * btree.
3927 *
3928 * This is done to prevent deadlocks. For example when COWing a node from the
3929 * extent btree we are holding a write lock on the node's parent and if we
3930 * trigger chunk allocation and attempted to insert the new block group item
3931 * in the extent btree right way, we could deadlock because the path for the
3932 * insertion can include that parent node. At first glance it seems impossible
3933 * to trigger chunk allocation after starting a transaction since tasks should
3934 * reserve enough transaction units (metadata space), however while that is true
3935 * most of the time, chunk allocation may still be triggered for several reasons:
3936 *
3937 * 1) When reserving metadata, we check if there is enough free space in the
3938 * metadata space_info and therefore don't trigger allocation of a new chunk.
3939 * However later when the task actually tries to COW an extent buffer from
3940 * the extent btree or from the device btree for example, it is forced to
3941 * allocate a new block group (chunk) because the only one that had enough
3942 * free space was just turned to RO mode by a running scrub for example (or
3943 * device replace, block group reclaim thread, etc), so we can not use it
3944 * for allocating an extent and end up being forced to allocate a new one;
3945 *
3946 * 2) Because we only check that the metadata space_info has enough free bytes,
3947 * we end up not allocating a new metadata chunk in that case. However if
3948 * the filesystem was mounted in degraded mode, none of the existing block
3949 * groups might be suitable for extent allocation due to their incompatible
3950 * profile (for e.g. mounting a 2 devices filesystem, where all block groups
3951 * use a RAID1 profile, in degraded mode using a single device). In this case
3952 * when the task attempts to COW some extent buffer of the extent btree for
3953 * example, it will trigger allocation of a new metadata block group with a
3954 * suitable profile (SINGLE profile in the example of the degraded mount of
3955 * the RAID1 filesystem);
3956 *
3957 * 3) The task has reserved enough transaction units / metadata space, but when
3958 * it attempts to COW an extent buffer from the extent or device btree for
3959 * example, it does not find any free extent in any metadata block group,
3960 * therefore forced to try to allocate a new metadata block group.
3961 * This is because some other task allocated all available extents in the
3962 * meanwhile - this typically happens with tasks that don't reserve space
3963 * properly, either intentionally or as a bug. One example where this is
3964 * done intentionally is fsync, as it does not reserve any transaction units
3965 * and ends up allocating a variable number of metadata extents for log
3966 * tree extent buffers;
3967 *
3968 * 4) The task has reserved enough transaction units / metadata space, but right
3969 * before it tries to allocate the last extent buffer it needs, a discard
3970 * operation comes in and, temporarily, removes the last free space entry from
3971 * the only metadata block group that had free space (discard starts by
3972 * removing a free space entry from a block group, then does the discard
3973 * operation and, once it's done, it adds back the free space entry to the
3974 * block group).
3975 *
3976 * We also need this 2 phases setup when adding a device to a filesystem with
3977 * a seed device - we must create new metadata and system chunks without adding
3978 * any of the block group items to the chunk, extent and device btrees. If we
3979 * did not do it this way, we would get ENOSPC when attempting to update those
3980 * btrees, since all the chunks from the seed device are read-only.
3981 *
3982 * Phase 1 does the updates and insertions to the chunk btree because if we had
3983 * it done in phase 2 and have a thundering herd of tasks allocating chunks in
3984 * parallel, we risk having too many system chunks allocated by many tasks if
3985 * many tasks reach phase 1 without the previous ones completing phase 2. In the
3986 * extreme case this leads to exhaustion of the system chunk array in the
3987 * superblock. This is easier to trigger if using a btree node/leaf size of 64K
3988 * and with RAID filesystems (so we have more device items in the chunk btree).
3989 * This has happened before and commit eafa4fd0ad0607 ("btrfs: fix exhaustion of
3990 * the system chunk array due to concurrent allocations") provides more details.
3991 *
3992 * Allocation of system chunks does not happen through this function. A task that
3993 * needs to update the chunk btree (the only btree that uses system chunks), must
3994 * preallocate chunk space by calling either check_system_chunk() or
3995 * btrfs_reserve_chunk_metadata() - the former is used when allocating a data or
3996 * metadata chunk or when removing a chunk, while the later is used before doing
3997 * a modification to the chunk btree - use cases for the later are adding,
3998 * removing and resizing a device as well as relocation of a system chunk.
3999 * See the comment below for more details.
4000 *
4001 * The reservation of system space, done through check_system_chunk(), as well
4002 * as all the updates and insertions into the chunk btree must be done while
4003 * holding fs_info->chunk_mutex. This is important to guarantee that while COWing
4004 * an extent buffer from the chunks btree we never trigger allocation of a new
4005 * system chunk, which would result in a deadlock (trying to lock twice an
4006 * extent buffer of the chunk btree, first time before triggering the chunk
4007 * allocation and the second time during chunk allocation while attempting to
4008 * update the chunks btree). The system chunk array is also updated while holding
4009 * that mutex. The same logic applies to removing chunks - we must reserve system
4010 * space, update the chunk btree and the system chunk array in the superblock
4011 * while holding fs_info->chunk_mutex.
4012 *
4013 * This function, btrfs_chunk_alloc(), belongs to phase 1.
4014 *
4015 * If @force is CHUNK_ALLOC_FORCE:
4016 * - return 1 if it successfully allocates a chunk,
4017 * - return errors including -ENOSPC otherwise.
4018 * If @force is NOT CHUNK_ALLOC_FORCE:
4019 * - return 0 if it doesn't need to allocate a new chunk,
4020 * - return 1 if it successfully allocates a chunk,
4021 * - return errors including -ENOSPC otherwise.
4022 */
4023int btrfs_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags,
4024 enum btrfs_chunk_alloc_enum force)
4025{
4026 struct btrfs_fs_info *fs_info = trans->fs_info;
4027 struct btrfs_space_info *space_info;
4028 struct btrfs_block_group *ret_bg;
4029 bool wait_for_alloc = false;
4030 bool should_alloc = false;
4031 bool from_extent_allocation = false;
4032 int ret = 0;
4033
4034 if (force == CHUNK_ALLOC_FORCE_FOR_EXTENT) {
4035 from_extent_allocation = true;
4036 force = CHUNK_ALLOC_FORCE;
4037 }
4038
4039 /* Don't re-enter if we're already allocating a chunk */
4040 if (trans->allocating_chunk)
4041 return -ENOSPC;
4042 /*
4043 * Allocation of system chunks can not happen through this path, as we
4044 * could end up in a deadlock if we are allocating a data or metadata
4045 * chunk and there is another task modifying the chunk btree.
4046 *
4047 * This is because while we are holding the chunk mutex, we will attempt
4048 * to add the new chunk item to the chunk btree or update an existing
4049 * device item in the chunk btree, while the other task that is modifying
4050 * the chunk btree is attempting to COW an extent buffer while holding a
4051 * lock on it and on its parent - if the COW operation triggers a system
4052 * chunk allocation, then we can deadlock because we are holding the
4053 * chunk mutex and we may need to access that extent buffer or its parent
4054 * in order to add the chunk item or update a device item.
4055 *
4056 * Tasks that want to modify the chunk tree should reserve system space
4057 * before updating the chunk btree, by calling either
4058 * btrfs_reserve_chunk_metadata() or check_system_chunk().
4059 * It's possible that after a task reserves the space, it still ends up
4060 * here - this happens in the cases described above at do_chunk_alloc().
4061 * The task will have to either retry or fail.
4062 */
4063 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4064 return -ENOSPC;
4065
4066 space_info = btrfs_find_space_info(fs_info, flags);
4067 ASSERT(space_info);
4068
4069 do {
4070 spin_lock(&space_info->lock);
4071 if (force < space_info->force_alloc)
4072 force = space_info->force_alloc;
4073 should_alloc = should_alloc_chunk(fs_info, space_info, force);
4074 if (space_info->full) {
4075 /* No more free physical space */
4076 if (should_alloc)
4077 ret = -ENOSPC;
4078 else
4079 ret = 0;
4080 spin_unlock(&space_info->lock);
4081 return ret;
4082 } else if (!should_alloc) {
4083 spin_unlock(&space_info->lock);
4084 return 0;
4085 } else if (space_info->chunk_alloc) {
4086 /*
4087 * Someone is already allocating, so we need to block
4088 * until this someone is finished and then loop to
4089 * recheck if we should continue with our allocation
4090 * attempt.
4091 */
4092 wait_for_alloc = true;
4093 force = CHUNK_ALLOC_NO_FORCE;
4094 spin_unlock(&space_info->lock);
4095 mutex_lock(&fs_info->chunk_mutex);
4096 mutex_unlock(&fs_info->chunk_mutex);
4097 } else {
4098 /* Proceed with allocation */
4099 space_info->chunk_alloc = 1;
4100 wait_for_alloc = false;
4101 spin_unlock(&space_info->lock);
4102 }
4103
4104 cond_resched();
4105 } while (wait_for_alloc);
4106
4107 mutex_lock(&fs_info->chunk_mutex);
4108 trans->allocating_chunk = true;
4109
4110 /*
4111 * If we have mixed data/metadata chunks we want to make sure we keep
4112 * allocating mixed chunks instead of individual chunks.
4113 */
4114 if (btrfs_mixed_space_info(space_info))
4115 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
4116
4117 /*
4118 * if we're doing a data chunk, go ahead and make sure that
4119 * we keep a reasonable number of metadata chunks allocated in the
4120 * FS as well.
4121 */
4122 if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
4123 fs_info->data_chunk_allocations++;
4124 if (!(fs_info->data_chunk_allocations %
4125 fs_info->metadata_ratio))
4126 force_metadata_allocation(fs_info);
4127 }
4128
4129 ret_bg = do_chunk_alloc(trans, flags);
4130 trans->allocating_chunk = false;
4131
4132 if (IS_ERR(ret_bg)) {
4133 ret = PTR_ERR(ret_bg);
4134 } else if (from_extent_allocation && (flags & BTRFS_BLOCK_GROUP_DATA)) {
4135 /*
4136 * New block group is likely to be used soon. Try to activate
4137 * it now. Failure is OK for now.
4138 */
4139 btrfs_zone_activate(ret_bg);
4140 }
4141
4142 if (!ret)
4143 btrfs_put_block_group(ret_bg);
4144
4145 spin_lock(&space_info->lock);
4146 if (ret < 0) {
4147 if (ret == -ENOSPC)
4148 space_info->full = 1;
4149 else
4150 goto out;
4151 } else {
4152 ret = 1;
4153 space_info->max_extent_size = 0;
4154 }
4155
4156 space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4157out:
4158 space_info->chunk_alloc = 0;
4159 spin_unlock(&space_info->lock);
4160 mutex_unlock(&fs_info->chunk_mutex);
4161
4162 return ret;
4163}
4164
4165static u64 get_profile_num_devs(struct btrfs_fs_info *fs_info, u64 type)
4166{
4167 u64 num_dev;
4168
4169 num_dev = btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)].devs_max;
4170 if (!num_dev)
4171 num_dev = fs_info->fs_devices->rw_devices;
4172
4173 return num_dev;
4174}
4175
4176static void reserve_chunk_space(struct btrfs_trans_handle *trans,
4177 u64 bytes,
4178 u64 type)
4179{
4180 struct btrfs_fs_info *fs_info = trans->fs_info;
4181 struct btrfs_space_info *info;
4182 u64 left;
4183 int ret = 0;
4184
4185 /*
4186 * Needed because we can end up allocating a system chunk and for an
4187 * atomic and race free space reservation in the chunk block reserve.
4188 */
4189 lockdep_assert_held(&fs_info->chunk_mutex);
4190
4191 info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4192 spin_lock(&info->lock);
4193 left = info->total_bytes - btrfs_space_info_used(info, true);
4194 spin_unlock(&info->lock);
4195
4196 if (left < bytes && btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
4197 btrfs_info(fs_info, "left=%llu, need=%llu, flags=%llu",
4198 left, bytes, type);
4199 btrfs_dump_space_info(fs_info, info, 0, 0);
4200 }
4201
4202 if (left < bytes) {
4203 u64 flags = btrfs_system_alloc_profile(fs_info);
4204 struct btrfs_block_group *bg;
4205
4206 /*
4207 * Ignore failure to create system chunk. We might end up not
4208 * needing it, as we might not need to COW all nodes/leafs from
4209 * the paths we visit in the chunk tree (they were already COWed
4210 * or created in the current transaction for example).
4211 */
4212 bg = btrfs_create_chunk(trans, flags);
4213 if (IS_ERR(bg)) {
4214 ret = PTR_ERR(bg);
4215 } else {
4216 /*
4217 * We have a new chunk. We also need to activate it for
4218 * zoned filesystem.
4219 */
4220 ret = btrfs_zoned_activate_one_bg(fs_info, info, true);
4221 if (ret < 0)
4222 return;
4223
4224 /*
4225 * If we fail to add the chunk item here, we end up
4226 * trying again at phase 2 of chunk allocation, at
4227 * btrfs_create_pending_block_groups(). So ignore
4228 * any error here. An ENOSPC here could happen, due to
4229 * the cases described at do_chunk_alloc() - the system
4230 * block group we just created was just turned into RO
4231 * mode by a scrub for example, or a running discard
4232 * temporarily removed its free space entries, etc.
4233 */
4234 btrfs_chunk_alloc_add_chunk_item(trans, bg);
4235 }
4236 }
4237
4238 if (!ret) {
4239 ret = btrfs_block_rsv_add(fs_info,
4240 &fs_info->chunk_block_rsv,
4241 bytes, BTRFS_RESERVE_NO_FLUSH);
4242 if (!ret)
4243 trans->chunk_bytes_reserved += bytes;
4244 }
4245}
4246
4247/*
4248 * Reserve space in the system space for allocating or removing a chunk.
4249 * The caller must be holding fs_info->chunk_mutex.
4250 */
4251void check_system_chunk(struct btrfs_trans_handle *trans, u64 type)
4252{
4253 struct btrfs_fs_info *fs_info = trans->fs_info;
4254 const u64 num_devs = get_profile_num_devs(fs_info, type);
4255 u64 bytes;
4256
4257 /* num_devs device items to update and 1 chunk item to add or remove. */
4258 bytes = btrfs_calc_metadata_size(fs_info, num_devs) +
4259 btrfs_calc_insert_metadata_size(fs_info, 1);
4260
4261 reserve_chunk_space(trans, bytes, type);
4262}
4263
4264/*
4265 * Reserve space in the system space, if needed, for doing a modification to the
4266 * chunk btree.
4267 *
4268 * @trans: A transaction handle.
4269 * @is_item_insertion: Indicate if the modification is for inserting a new item
4270 * in the chunk btree or if it's for the deletion or update
4271 * of an existing item.
4272 *
4273 * This is used in a context where we need to update the chunk btree outside
4274 * block group allocation and removal, to avoid a deadlock with a concurrent
4275 * task that is allocating a metadata or data block group and therefore needs to
4276 * update the chunk btree while holding the chunk mutex. After the update to the
4277 * chunk btree is done, btrfs_trans_release_chunk_metadata() should be called.
4278 *
4279 */
4280void btrfs_reserve_chunk_metadata(struct btrfs_trans_handle *trans,
4281 bool is_item_insertion)
4282{
4283 struct btrfs_fs_info *fs_info = trans->fs_info;
4284 u64 bytes;
4285
4286 if (is_item_insertion)
4287 bytes = btrfs_calc_insert_metadata_size(fs_info, 1);
4288 else
4289 bytes = btrfs_calc_metadata_size(fs_info, 1);
4290
4291 mutex_lock(&fs_info->chunk_mutex);
4292 reserve_chunk_space(trans, bytes, BTRFS_BLOCK_GROUP_SYSTEM);
4293 mutex_unlock(&fs_info->chunk_mutex);
4294}
4295
4296void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
4297{
4298 struct btrfs_block_group *block_group;
4299
4300 block_group = btrfs_lookup_first_block_group(info, 0);
4301 while (block_group) {
4302 btrfs_wait_block_group_cache_done(block_group);
4303 spin_lock(&block_group->lock);
4304 if (test_and_clear_bit(BLOCK_GROUP_FLAG_IREF,
4305 &block_group->runtime_flags)) {
4306 struct inode *inode = block_group->inode;
4307
4308 block_group->inode = NULL;
4309 spin_unlock(&block_group->lock);
4310
4311 ASSERT(block_group->io_ctl.inode == NULL);
4312 iput(inode);
4313 } else {
4314 spin_unlock(&block_group->lock);
4315 }
4316 block_group = btrfs_next_block_group(block_group);
4317 }
4318}
4319
4320/*
4321 * Must be called only after stopping all workers, since we could have block
4322 * group caching kthreads running, and therefore they could race with us if we
4323 * freed the block groups before stopping them.
4324 */
4325int btrfs_free_block_groups(struct btrfs_fs_info *info)
4326{
4327 struct btrfs_block_group *block_group;
4328 struct btrfs_space_info *space_info;
4329 struct btrfs_caching_control *caching_ctl;
4330 struct rb_node *n;
4331
4332 if (btrfs_is_zoned(info)) {
4333 if (info->active_meta_bg) {
4334 btrfs_put_block_group(info->active_meta_bg);
4335 info->active_meta_bg = NULL;
4336 }
4337 if (info->active_system_bg) {
4338 btrfs_put_block_group(info->active_system_bg);
4339 info->active_system_bg = NULL;
4340 }
4341 }
4342
4343 write_lock(&info->block_group_cache_lock);
4344 while (!list_empty(&info->caching_block_groups)) {
4345 caching_ctl = list_entry(info->caching_block_groups.next,
4346 struct btrfs_caching_control, list);
4347 list_del(&caching_ctl->list);
4348 btrfs_put_caching_control(caching_ctl);
4349 }
4350 write_unlock(&info->block_group_cache_lock);
4351
4352 spin_lock(&info->unused_bgs_lock);
4353 while (!list_empty(&info->unused_bgs)) {
4354 block_group = list_first_entry(&info->unused_bgs,
4355 struct btrfs_block_group,
4356 bg_list);
4357 list_del_init(&block_group->bg_list);
4358 btrfs_put_block_group(block_group);
4359 }
4360
4361 while (!list_empty(&info->reclaim_bgs)) {
4362 block_group = list_first_entry(&info->reclaim_bgs,
4363 struct btrfs_block_group,
4364 bg_list);
4365 list_del_init(&block_group->bg_list);
4366 btrfs_put_block_group(block_group);
4367 }
4368 spin_unlock(&info->unused_bgs_lock);
4369
4370 spin_lock(&info->zone_active_bgs_lock);
4371 while (!list_empty(&info->zone_active_bgs)) {
4372 block_group = list_first_entry(&info->zone_active_bgs,
4373 struct btrfs_block_group,
4374 active_bg_list);
4375 list_del_init(&block_group->active_bg_list);
4376 btrfs_put_block_group(block_group);
4377 }
4378 spin_unlock(&info->zone_active_bgs_lock);
4379
4380 write_lock(&info->block_group_cache_lock);
4381 while ((n = rb_last(&info->block_group_cache_tree.rb_root)) != NULL) {
4382 block_group = rb_entry(n, struct btrfs_block_group,
4383 cache_node);
4384 rb_erase_cached(&block_group->cache_node,
4385 &info->block_group_cache_tree);
4386 RB_CLEAR_NODE(&block_group->cache_node);
4387 write_unlock(&info->block_group_cache_lock);
4388
4389 down_write(&block_group->space_info->groups_sem);
4390 list_del(&block_group->list);
4391 up_write(&block_group->space_info->groups_sem);
4392
4393 /*
4394 * We haven't cached this block group, which means we could
4395 * possibly have excluded extents on this block group.
4396 */
4397 if (block_group->cached == BTRFS_CACHE_NO ||
4398 block_group->cached == BTRFS_CACHE_ERROR)
4399 btrfs_free_excluded_extents(block_group);
4400
4401 btrfs_remove_free_space_cache(block_group);
4402 ASSERT(block_group->cached != BTRFS_CACHE_STARTED);
4403 ASSERT(list_empty(&block_group->dirty_list));
4404 ASSERT(list_empty(&block_group->io_list));
4405 ASSERT(list_empty(&block_group->bg_list));
4406 ASSERT(refcount_read(&block_group->refs) == 1);
4407 ASSERT(block_group->swap_extents == 0);
4408 btrfs_put_block_group(block_group);
4409
4410 write_lock(&info->block_group_cache_lock);
4411 }
4412 write_unlock(&info->block_group_cache_lock);
4413
4414 btrfs_release_global_block_rsv(info);
4415
4416 while (!list_empty(&info->space_info)) {
4417 space_info = list_entry(info->space_info.next,
4418 struct btrfs_space_info,
4419 list);
4420
4421 /*
4422 * Do not hide this behind enospc_debug, this is actually
4423 * important and indicates a real bug if this happens.
4424 */
4425 if (WARN_ON(space_info->bytes_pinned > 0 ||
4426 space_info->bytes_may_use > 0))
4427 btrfs_dump_space_info(info, space_info, 0, 0);
4428
4429 /*
4430 * If there was a failure to cleanup a log tree, very likely due
4431 * to an IO failure on a writeback attempt of one or more of its
4432 * extent buffers, we could not do proper (and cheap) unaccounting
4433 * of their reserved space, so don't warn on bytes_reserved > 0 in
4434 * that case.
4435 */
4436 if (!(space_info->flags & BTRFS_BLOCK_GROUP_METADATA) ||
4437 !BTRFS_FS_LOG_CLEANUP_ERROR(info)) {
4438 if (WARN_ON(space_info->bytes_reserved > 0))
4439 btrfs_dump_space_info(info, space_info, 0, 0);
4440 }
4441
4442 WARN_ON(space_info->reclaim_size > 0);
4443 list_del(&space_info->list);
4444 btrfs_sysfs_remove_space_info(space_info);
4445 }
4446 return 0;
4447}
4448
4449void btrfs_freeze_block_group(struct btrfs_block_group *cache)
4450{
4451 atomic_inc(&cache->frozen);
4452}
4453
4454void btrfs_unfreeze_block_group(struct btrfs_block_group *block_group)
4455{
4456 struct btrfs_fs_info *fs_info = block_group->fs_info;
4457 bool cleanup;
4458
4459 spin_lock(&block_group->lock);
4460 cleanup = (atomic_dec_and_test(&block_group->frozen) &&
4461 test_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags));
4462 spin_unlock(&block_group->lock);
4463
4464 if (cleanup) {
4465 struct btrfs_chunk_map *map;
4466
4467 map = btrfs_find_chunk_map(fs_info, block_group->start, 1);
4468 /* Logic error, can't happen. */
4469 ASSERT(map);
4470
4471 btrfs_remove_chunk_map(fs_info, map);
4472
4473 /* Once for our lookup reference. */
4474 btrfs_free_chunk_map(map);
4475
4476 /*
4477 * We may have left one free space entry and other possible
4478 * tasks trimming this block group have left 1 entry each one.
4479 * Free them if any.
4480 */
4481 btrfs_remove_free_space_cache(block_group);
4482 }
4483}
4484
4485bool btrfs_inc_block_group_swap_extents(struct btrfs_block_group *bg)
4486{
4487 bool ret = true;
4488
4489 spin_lock(&bg->lock);
4490 if (bg->ro)
4491 ret = false;
4492 else
4493 bg->swap_extents++;
4494 spin_unlock(&bg->lock);
4495
4496 return ret;
4497}
4498
4499void btrfs_dec_block_group_swap_extents(struct btrfs_block_group *bg, int amount)
4500{
4501 spin_lock(&bg->lock);
4502 ASSERT(!bg->ro);
4503 ASSERT(bg->swap_extents >= amount);
4504 bg->swap_extents -= amount;
4505 spin_unlock(&bg->lock);
4506}
4507
4508enum btrfs_block_group_size_class btrfs_calc_block_group_size_class(u64 size)
4509{
4510 if (size <= SZ_128K)
4511 return BTRFS_BG_SZ_SMALL;
4512 if (size <= SZ_8M)
4513 return BTRFS_BG_SZ_MEDIUM;
4514 return BTRFS_BG_SZ_LARGE;
4515}
4516
4517/*
4518 * Handle a block group allocating an extent in a size class
4519 *
4520 * @bg: The block group we allocated in.
4521 * @size_class: The size class of the allocation.
4522 * @force_wrong_size_class: Whether we are desperate enough to allow
4523 * mismatched size classes.
4524 *
4525 * Returns: 0 if the size class was valid for this block_group, -EAGAIN in the
4526 * case of a race that leads to the wrong size class without
4527 * force_wrong_size_class set.
4528 *
4529 * find_free_extent will skip block groups with a mismatched size class until
4530 * it really needs to avoid ENOSPC. In that case it will set
4531 * force_wrong_size_class. However, if a block group is newly allocated and
4532 * doesn't yet have a size class, then it is possible for two allocations of
4533 * different sizes to race and both try to use it. The loser is caught here and
4534 * has to retry.
4535 */
4536int btrfs_use_block_group_size_class(struct btrfs_block_group *bg,
4537 enum btrfs_block_group_size_class size_class,
4538 bool force_wrong_size_class)
4539{
4540 ASSERT(size_class != BTRFS_BG_SZ_NONE);
4541
4542 /* The new allocation is in the right size class, do nothing */
4543 if (bg->size_class == size_class)
4544 return 0;
4545 /*
4546 * The new allocation is in a mismatched size class.
4547 * This means one of two things:
4548 *
4549 * 1. Two tasks in find_free_extent for different size_classes raced
4550 * and hit the same empty block_group. Make the loser try again.
4551 * 2. A call to find_free_extent got desperate enough to set
4552 * 'force_wrong_slab'. Don't change the size_class, but allow the
4553 * allocation.
4554 */
4555 if (bg->size_class != BTRFS_BG_SZ_NONE) {
4556 if (force_wrong_size_class)
4557 return 0;
4558 return -EAGAIN;
4559 }
4560 /*
4561 * The happy new block group case: the new allocation is the first
4562 * one in the block_group so we set size_class.
4563 */
4564 bg->size_class = size_class;
4565
4566 return 0;
4567}
4568
4569bool btrfs_block_group_should_use_size_class(struct btrfs_block_group *bg)
4570{
4571 if (btrfs_is_zoned(bg->fs_info))
4572 return false;
4573 if (!btrfs_is_block_group_data_only(bg))
4574 return false;
4575 return true;
4576}
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#include "zoned.h"
19
20/*
21 * Return target flags in extended format or 0 if restripe for this chunk_type
22 * is not in progress
23 *
24 * Should be called with balance_lock held
25 */
26static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
27{
28 struct btrfs_balance_control *bctl = fs_info->balance_ctl;
29 u64 target = 0;
30
31 if (!bctl)
32 return 0;
33
34 if (flags & BTRFS_BLOCK_GROUP_DATA &&
35 bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
36 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
37 } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
38 bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
39 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
40 } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
41 bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
42 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
43 }
44
45 return target;
46}
47
48/*
49 * @flags: available profiles in extended format (see ctree.h)
50 *
51 * Return reduced profile in chunk format. If profile changing is in progress
52 * (either running or paused) picks the target profile (if it's already
53 * available), otherwise falls back to plain reducing.
54 */
55static u64 btrfs_reduce_alloc_profile(struct btrfs_fs_info *fs_info, u64 flags)
56{
57 u64 num_devices = fs_info->fs_devices->rw_devices;
58 u64 target;
59 u64 raid_type;
60 u64 allowed = 0;
61
62 /*
63 * See if restripe for this chunk_type is in progress, if so try to
64 * reduce to the target profile
65 */
66 spin_lock(&fs_info->balance_lock);
67 target = get_restripe_target(fs_info, flags);
68 if (target) {
69 spin_unlock(&fs_info->balance_lock);
70 return extended_to_chunk(target);
71 }
72 spin_unlock(&fs_info->balance_lock);
73
74 /* First, mask out the RAID levels which aren't possible */
75 for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
76 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
77 allowed |= btrfs_raid_array[raid_type].bg_flag;
78 }
79 allowed &= flags;
80
81 if (allowed & BTRFS_BLOCK_GROUP_RAID6)
82 allowed = BTRFS_BLOCK_GROUP_RAID6;
83 else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
84 allowed = BTRFS_BLOCK_GROUP_RAID5;
85 else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
86 allowed = BTRFS_BLOCK_GROUP_RAID10;
87 else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
88 allowed = BTRFS_BLOCK_GROUP_RAID1;
89 else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
90 allowed = BTRFS_BLOCK_GROUP_RAID0;
91
92 flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
93
94 return extended_to_chunk(flags | allowed);
95}
96
97u64 btrfs_get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags)
98{
99 unsigned seq;
100 u64 flags;
101
102 do {
103 flags = orig_flags;
104 seq = read_seqbegin(&fs_info->profiles_lock);
105
106 if (flags & BTRFS_BLOCK_GROUP_DATA)
107 flags |= fs_info->avail_data_alloc_bits;
108 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
109 flags |= fs_info->avail_system_alloc_bits;
110 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
111 flags |= fs_info->avail_metadata_alloc_bits;
112 } while (read_seqretry(&fs_info->profiles_lock, seq));
113
114 return btrfs_reduce_alloc_profile(fs_info, flags);
115}
116
117void btrfs_get_block_group(struct btrfs_block_group *cache)
118{
119 refcount_inc(&cache->refs);
120}
121
122void btrfs_put_block_group(struct btrfs_block_group *cache)
123{
124 if (refcount_dec_and_test(&cache->refs)) {
125 WARN_ON(cache->pinned > 0);
126 WARN_ON(cache->reserved > 0);
127
128 /*
129 * A block_group shouldn't be on the discard_list anymore.
130 * Remove the block_group from the discard_list to prevent us
131 * from causing a panic due to NULL pointer dereference.
132 */
133 if (WARN_ON(!list_empty(&cache->discard_list)))
134 btrfs_discard_cancel_work(&cache->fs_info->discard_ctl,
135 cache);
136
137 /*
138 * If not empty, someone is still holding mutex of
139 * full_stripe_lock, which can only be released by caller.
140 * And it will definitely cause use-after-free when caller
141 * tries to release full stripe lock.
142 *
143 * No better way to resolve, but only to warn.
144 */
145 WARN_ON(!RB_EMPTY_ROOT(&cache->full_stripe_locks_root.root));
146 kfree(cache->free_space_ctl);
147 kfree(cache);
148 }
149}
150
151/*
152 * This adds the block group to the fs_info rb tree for the block group cache
153 */
154static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
155 struct btrfs_block_group *block_group)
156{
157 struct rb_node **p;
158 struct rb_node *parent = NULL;
159 struct btrfs_block_group *cache;
160
161 ASSERT(block_group->length != 0);
162
163 spin_lock(&info->block_group_cache_lock);
164 p = &info->block_group_cache_tree.rb_node;
165
166 while (*p) {
167 parent = *p;
168 cache = rb_entry(parent, struct btrfs_block_group, cache_node);
169 if (block_group->start < cache->start) {
170 p = &(*p)->rb_left;
171 } else if (block_group->start > cache->start) {
172 p = &(*p)->rb_right;
173 } else {
174 spin_unlock(&info->block_group_cache_lock);
175 return -EEXIST;
176 }
177 }
178
179 rb_link_node(&block_group->cache_node, parent, p);
180 rb_insert_color(&block_group->cache_node,
181 &info->block_group_cache_tree);
182
183 if (info->first_logical_byte > block_group->start)
184 info->first_logical_byte = block_group->start;
185
186 spin_unlock(&info->block_group_cache_lock);
187
188 return 0;
189}
190
191/*
192 * This will return the block group at or after bytenr if contains is 0, else
193 * it will return the block group that contains the bytenr
194 */
195static struct btrfs_block_group *block_group_cache_tree_search(
196 struct btrfs_fs_info *info, u64 bytenr, int contains)
197{
198 struct btrfs_block_group *cache, *ret = NULL;
199 struct rb_node *n;
200 u64 end, start;
201
202 spin_lock(&info->block_group_cache_lock);
203 n = info->block_group_cache_tree.rb_node;
204
205 while (n) {
206 cache = rb_entry(n, struct btrfs_block_group, cache_node);
207 end = cache->start + cache->length - 1;
208 start = cache->start;
209
210 if (bytenr < start) {
211 if (!contains && (!ret || start < ret->start))
212 ret = cache;
213 n = n->rb_left;
214 } else if (bytenr > start) {
215 if (contains && bytenr <= end) {
216 ret = cache;
217 break;
218 }
219 n = n->rb_right;
220 } else {
221 ret = cache;
222 break;
223 }
224 }
225 if (ret) {
226 btrfs_get_block_group(ret);
227 if (bytenr == 0 && info->first_logical_byte > ret->start)
228 info->first_logical_byte = ret->start;
229 }
230 spin_unlock(&info->block_group_cache_lock);
231
232 return ret;
233}
234
235/*
236 * Return the block group that starts at or after bytenr
237 */
238struct btrfs_block_group *btrfs_lookup_first_block_group(
239 struct btrfs_fs_info *info, u64 bytenr)
240{
241 return block_group_cache_tree_search(info, bytenr, 0);
242}
243
244/*
245 * Return the block group that contains the given bytenr
246 */
247struct btrfs_block_group *btrfs_lookup_block_group(
248 struct btrfs_fs_info *info, u64 bytenr)
249{
250 return block_group_cache_tree_search(info, bytenr, 1);
251}
252
253struct btrfs_block_group *btrfs_next_block_group(
254 struct btrfs_block_group *cache)
255{
256 struct btrfs_fs_info *fs_info = cache->fs_info;
257 struct rb_node *node;
258
259 spin_lock(&fs_info->block_group_cache_lock);
260
261 /* If our block group was removed, we need a full search. */
262 if (RB_EMPTY_NODE(&cache->cache_node)) {
263 const u64 next_bytenr = cache->start + cache->length;
264
265 spin_unlock(&fs_info->block_group_cache_lock);
266 btrfs_put_block_group(cache);
267 cache = btrfs_lookup_first_block_group(fs_info, next_bytenr); return cache;
268 }
269 node = rb_next(&cache->cache_node);
270 btrfs_put_block_group(cache);
271 if (node) {
272 cache = rb_entry(node, struct btrfs_block_group, cache_node);
273 btrfs_get_block_group(cache);
274 } else
275 cache = NULL;
276 spin_unlock(&fs_info->block_group_cache_lock);
277 return cache;
278}
279
280bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
281{
282 struct btrfs_block_group *bg;
283 bool ret = true;
284
285 bg = btrfs_lookup_block_group(fs_info, bytenr);
286 if (!bg)
287 return false;
288
289 spin_lock(&bg->lock);
290 if (bg->ro)
291 ret = false;
292 else
293 atomic_inc(&bg->nocow_writers);
294 spin_unlock(&bg->lock);
295
296 /* No put on block group, done by btrfs_dec_nocow_writers */
297 if (!ret)
298 btrfs_put_block_group(bg);
299
300 return ret;
301}
302
303void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
304{
305 struct btrfs_block_group *bg;
306
307 bg = btrfs_lookup_block_group(fs_info, bytenr);
308 ASSERT(bg);
309 if (atomic_dec_and_test(&bg->nocow_writers))
310 wake_up_var(&bg->nocow_writers);
311 /*
312 * Once for our lookup and once for the lookup done by a previous call
313 * to btrfs_inc_nocow_writers()
314 */
315 btrfs_put_block_group(bg);
316 btrfs_put_block_group(bg);
317}
318
319void btrfs_wait_nocow_writers(struct btrfs_block_group *bg)
320{
321 wait_var_event(&bg->nocow_writers, !atomic_read(&bg->nocow_writers));
322}
323
324void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
325 const u64 start)
326{
327 struct btrfs_block_group *bg;
328
329 bg = btrfs_lookup_block_group(fs_info, start);
330 ASSERT(bg);
331 if (atomic_dec_and_test(&bg->reservations))
332 wake_up_var(&bg->reservations);
333 btrfs_put_block_group(bg);
334}
335
336void btrfs_wait_block_group_reservations(struct btrfs_block_group *bg)
337{
338 struct btrfs_space_info *space_info = bg->space_info;
339
340 ASSERT(bg->ro);
341
342 if (!(bg->flags & BTRFS_BLOCK_GROUP_DATA))
343 return;
344
345 /*
346 * Our block group is read only but before we set it to read only,
347 * some task might have had allocated an extent from it already, but it
348 * has not yet created a respective ordered extent (and added it to a
349 * root's list of ordered extents).
350 * Therefore wait for any task currently allocating extents, since the
351 * block group's reservations counter is incremented while a read lock
352 * on the groups' semaphore is held and decremented after releasing
353 * the read access on that semaphore and creating the ordered extent.
354 */
355 down_write(&space_info->groups_sem);
356 up_write(&space_info->groups_sem);
357
358 wait_var_event(&bg->reservations, !atomic_read(&bg->reservations));
359}
360
361struct btrfs_caching_control *btrfs_get_caching_control(
362 struct btrfs_block_group *cache)
363{
364 struct btrfs_caching_control *ctl;
365
366 spin_lock(&cache->lock);
367 if (!cache->caching_ctl) {
368 spin_unlock(&cache->lock);
369 return NULL;
370 }
371
372 ctl = cache->caching_ctl;
373 refcount_inc(&ctl->count);
374 spin_unlock(&cache->lock);
375 return ctl;
376}
377
378void btrfs_put_caching_control(struct btrfs_caching_control *ctl)
379{
380 if (refcount_dec_and_test(&ctl->count))
381 kfree(ctl);
382}
383
384/*
385 * When we wait for progress in the block group caching, its because our
386 * allocation attempt failed at least once. So, we must sleep and let some
387 * progress happen before we try again.
388 *
389 * This function will sleep at least once waiting for new free space to show
390 * up, and then it will check the block group free space numbers for our min
391 * num_bytes. Another option is to have it go ahead and look in the rbtree for
392 * a free extent of a given size, but this is a good start.
393 *
394 * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
395 * any of the information in this block group.
396 */
397void btrfs_wait_block_group_cache_progress(struct btrfs_block_group *cache,
398 u64 num_bytes)
399{
400 struct btrfs_caching_control *caching_ctl;
401
402 caching_ctl = btrfs_get_caching_control(cache);
403 if (!caching_ctl)
404 return;
405
406 wait_event(caching_ctl->wait, btrfs_block_group_done(cache) ||
407 (cache->free_space_ctl->free_space >= num_bytes));
408
409 btrfs_put_caching_control(caching_ctl);
410}
411
412int btrfs_wait_block_group_cache_done(struct btrfs_block_group *cache)
413{
414 struct btrfs_caching_control *caching_ctl;
415 int ret = 0;
416
417 caching_ctl = btrfs_get_caching_control(cache);
418 if (!caching_ctl)
419 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
420
421 wait_event(caching_ctl->wait, btrfs_block_group_done(cache));
422 if (cache->cached == BTRFS_CACHE_ERROR)
423 ret = -EIO;
424 btrfs_put_caching_control(caching_ctl);
425 return ret;
426}
427
428static bool space_cache_v1_done(struct btrfs_block_group *cache)
429{
430 bool ret;
431
432 spin_lock(&cache->lock);
433 ret = cache->cached != BTRFS_CACHE_FAST;
434 spin_unlock(&cache->lock);
435
436 return ret;
437}
438
439void btrfs_wait_space_cache_v1_finished(struct btrfs_block_group *cache,
440 struct btrfs_caching_control *caching_ctl)
441{
442 wait_event(caching_ctl->wait, space_cache_v1_done(cache));
443}
444
445#ifdef CONFIG_BTRFS_DEBUG
446static void fragment_free_space(struct btrfs_block_group *block_group)
447{
448 struct btrfs_fs_info *fs_info = block_group->fs_info;
449 u64 start = block_group->start;
450 u64 len = block_group->length;
451 u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ?
452 fs_info->nodesize : fs_info->sectorsize;
453 u64 step = chunk << 1;
454
455 while (len > chunk) {
456 btrfs_remove_free_space(block_group, start, chunk);
457 start += step;
458 if (len < step)
459 len = 0;
460 else
461 len -= step;
462 }
463}
464#endif
465
466/*
467 * This is only called by btrfs_cache_block_group, since we could have freed
468 * extents we need to check the pinned_extents for any extents that can't be
469 * used yet since their free space will be released as soon as the transaction
470 * commits.
471 */
472u64 add_new_free_space(struct btrfs_block_group *block_group, u64 start, u64 end)
473{
474 struct btrfs_fs_info *info = block_group->fs_info;
475 u64 extent_start, extent_end, size, total_added = 0;
476 int ret;
477
478 while (start < end) {
479 ret = find_first_extent_bit(&info->excluded_extents, start,
480 &extent_start, &extent_end,
481 EXTENT_DIRTY | EXTENT_UPTODATE,
482 NULL);
483 if (ret)
484 break;
485
486 if (extent_start <= start) {
487 start = extent_end + 1;
488 } else if (extent_start > start && extent_start < end) {
489 size = extent_start - start;
490 total_added += size;
491 ret = btrfs_add_free_space_async_trimmed(block_group,
492 start, size);
493 BUG_ON(ret); /* -ENOMEM or logic error */
494 start = extent_end + 1;
495 } else {
496 break;
497 }
498 }
499
500 if (start < end) {
501 size = end - start;
502 total_added += size;
503 ret = btrfs_add_free_space_async_trimmed(block_group, start,
504 size);
505 BUG_ON(ret); /* -ENOMEM or logic error */
506 }
507
508 return total_added;
509}
510
511static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl)
512{
513 struct btrfs_block_group *block_group = caching_ctl->block_group;
514 struct btrfs_fs_info *fs_info = block_group->fs_info;
515 struct btrfs_root *extent_root = fs_info->extent_root;
516 struct btrfs_path *path;
517 struct extent_buffer *leaf;
518 struct btrfs_key key;
519 u64 total_found = 0;
520 u64 last = 0;
521 u32 nritems;
522 int ret;
523 bool wakeup = true;
524
525 path = btrfs_alloc_path();
526 if (!path)
527 return -ENOMEM;
528
529 last = max_t(u64, block_group->start, BTRFS_SUPER_INFO_OFFSET);
530
531#ifdef CONFIG_BTRFS_DEBUG
532 /*
533 * If we're fragmenting we don't want to make anybody think we can
534 * allocate from this block group until we've had a chance to fragment
535 * the free space.
536 */
537 if (btrfs_should_fragment_free_space(block_group))
538 wakeup = false;
539#endif
540 /*
541 * We don't want to deadlock with somebody trying to allocate a new
542 * extent for the extent root while also trying to search the extent
543 * root to add free space. So we skip locking and search the commit
544 * root, since its read-only
545 */
546 path->skip_locking = 1;
547 path->search_commit_root = 1;
548 path->reada = READA_FORWARD;
549
550 key.objectid = last;
551 key.offset = 0;
552 key.type = BTRFS_EXTENT_ITEM_KEY;
553
554next:
555 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
556 if (ret < 0)
557 goto out;
558
559 leaf = path->nodes[0];
560 nritems = btrfs_header_nritems(leaf);
561
562 while (1) {
563 if (btrfs_fs_closing(fs_info) > 1) {
564 last = (u64)-1;
565 break;
566 }
567
568 if (path->slots[0] < nritems) {
569 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
570 } else {
571 ret = btrfs_find_next_key(extent_root, path, &key, 0, 0);
572 if (ret)
573 break;
574
575 if (need_resched() ||
576 rwsem_is_contended(&fs_info->commit_root_sem)) {
577 if (wakeup)
578 caching_ctl->progress = last;
579 btrfs_release_path(path);
580 up_read(&fs_info->commit_root_sem);
581 mutex_unlock(&caching_ctl->mutex);
582 cond_resched();
583 mutex_lock(&caching_ctl->mutex);
584 down_read(&fs_info->commit_root_sem);
585 goto next;
586 }
587
588 ret = btrfs_next_leaf(extent_root, path);
589 if (ret < 0)
590 goto out;
591 if (ret)
592 break;
593 leaf = path->nodes[0];
594 nritems = btrfs_header_nritems(leaf);
595 continue;
596 }
597
598 if (key.objectid < last) {
599 key.objectid = last;
600 key.offset = 0;
601 key.type = BTRFS_EXTENT_ITEM_KEY;
602
603 if (wakeup)
604 caching_ctl->progress = last;
605 btrfs_release_path(path);
606 goto next;
607 }
608
609 if (key.objectid < block_group->start) {
610 path->slots[0]++;
611 continue;
612 }
613
614 if (key.objectid >= block_group->start + block_group->length)
615 break;
616
617 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
618 key.type == BTRFS_METADATA_ITEM_KEY) {
619 total_found += add_new_free_space(block_group, last,
620 key.objectid);
621 if (key.type == BTRFS_METADATA_ITEM_KEY)
622 last = key.objectid +
623 fs_info->nodesize;
624 else
625 last = key.objectid + key.offset;
626
627 if (total_found > CACHING_CTL_WAKE_UP) {
628 total_found = 0;
629 if (wakeup)
630 wake_up(&caching_ctl->wait);
631 }
632 }
633 path->slots[0]++;
634 }
635 ret = 0;
636
637 total_found += add_new_free_space(block_group, last,
638 block_group->start + block_group->length);
639 caching_ctl->progress = (u64)-1;
640
641out:
642 btrfs_free_path(path);
643 return ret;
644}
645
646static noinline void caching_thread(struct btrfs_work *work)
647{
648 struct btrfs_block_group *block_group;
649 struct btrfs_fs_info *fs_info;
650 struct btrfs_caching_control *caching_ctl;
651 int ret;
652
653 caching_ctl = container_of(work, struct btrfs_caching_control, work);
654 block_group = caching_ctl->block_group;
655 fs_info = block_group->fs_info;
656
657 mutex_lock(&caching_ctl->mutex);
658 down_read(&fs_info->commit_root_sem);
659
660 if (btrfs_test_opt(fs_info, SPACE_CACHE)) {
661 ret = load_free_space_cache(block_group);
662 if (ret == 1) {
663 ret = 0;
664 goto done;
665 }
666
667 /*
668 * We failed to load the space cache, set ourselves to
669 * CACHE_STARTED and carry on.
670 */
671 spin_lock(&block_group->lock);
672 block_group->cached = BTRFS_CACHE_STARTED;
673 spin_unlock(&block_group->lock);
674 wake_up(&caching_ctl->wait);
675 }
676
677 /*
678 * If we are in the transaction that populated the free space tree we
679 * can't actually cache from the free space tree as our commit root and
680 * real root are the same, so we could change the contents of the blocks
681 * while caching. Instead do the slow caching in this case, and after
682 * the transaction has committed we will be safe.
683 */
684 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) &&
685 !(test_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags)))
686 ret = load_free_space_tree(caching_ctl);
687 else
688 ret = load_extent_tree_free(caching_ctl);
689done:
690 spin_lock(&block_group->lock);
691 block_group->caching_ctl = NULL;
692 block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED;
693 spin_unlock(&block_group->lock);
694
695#ifdef CONFIG_BTRFS_DEBUG
696 if (btrfs_should_fragment_free_space(block_group)) {
697 u64 bytes_used;
698
699 spin_lock(&block_group->space_info->lock);
700 spin_lock(&block_group->lock);
701 bytes_used = block_group->length - block_group->used;
702 block_group->space_info->bytes_used += bytes_used >> 1;
703 spin_unlock(&block_group->lock);
704 spin_unlock(&block_group->space_info->lock);
705 fragment_free_space(block_group);
706 }
707#endif
708
709 caching_ctl->progress = (u64)-1;
710
711 up_read(&fs_info->commit_root_sem);
712 btrfs_free_excluded_extents(block_group);
713 mutex_unlock(&caching_ctl->mutex);
714
715 wake_up(&caching_ctl->wait);
716
717 btrfs_put_caching_control(caching_ctl);
718 btrfs_put_block_group(block_group);
719}
720
721int btrfs_cache_block_group(struct btrfs_block_group *cache, int load_cache_only)
722{
723 DEFINE_WAIT(wait);
724 struct btrfs_fs_info *fs_info = cache->fs_info;
725 struct btrfs_caching_control *caching_ctl = NULL;
726 int ret = 0;
727
728 /* Allocator for zoned filesystems does not use the cache at all */
729 if (btrfs_is_zoned(fs_info))
730 return 0;
731
732 caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
733 if (!caching_ctl)
734 return -ENOMEM;
735
736 INIT_LIST_HEAD(&caching_ctl->list);
737 mutex_init(&caching_ctl->mutex);
738 init_waitqueue_head(&caching_ctl->wait);
739 caching_ctl->block_group = cache;
740 caching_ctl->progress = cache->start;
741 refcount_set(&caching_ctl->count, 2);
742 btrfs_init_work(&caching_ctl->work, caching_thread, NULL, NULL);
743
744 spin_lock(&cache->lock);
745 if (cache->cached != BTRFS_CACHE_NO) {
746 kfree(caching_ctl);
747
748 caching_ctl = cache->caching_ctl;
749 if (caching_ctl)
750 refcount_inc(&caching_ctl->count);
751 spin_unlock(&cache->lock);
752 goto out;
753 }
754 WARN_ON(cache->caching_ctl);
755 cache->caching_ctl = caching_ctl;
756 if (btrfs_test_opt(fs_info, SPACE_CACHE))
757 cache->cached = BTRFS_CACHE_FAST;
758 else
759 cache->cached = BTRFS_CACHE_STARTED;
760 cache->has_caching_ctl = 1;
761 spin_unlock(&cache->lock);
762
763 spin_lock(&fs_info->block_group_cache_lock);
764 refcount_inc(&caching_ctl->count);
765 list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
766 spin_unlock(&fs_info->block_group_cache_lock);
767
768 btrfs_get_block_group(cache);
769
770 btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
771out:
772 if (load_cache_only && caching_ctl)
773 btrfs_wait_space_cache_v1_finished(cache, caching_ctl);
774 if (caching_ctl)
775 btrfs_put_caching_control(caching_ctl);
776
777 return ret;
778}
779
780static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
781{
782 u64 extra_flags = chunk_to_extended(flags) &
783 BTRFS_EXTENDED_PROFILE_MASK;
784
785 write_seqlock(&fs_info->profiles_lock);
786 if (flags & BTRFS_BLOCK_GROUP_DATA)
787 fs_info->avail_data_alloc_bits &= ~extra_flags;
788 if (flags & BTRFS_BLOCK_GROUP_METADATA)
789 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
790 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
791 fs_info->avail_system_alloc_bits &= ~extra_flags;
792 write_sequnlock(&fs_info->profiles_lock);
793}
794
795/*
796 * Clear incompat bits for the following feature(s):
797 *
798 * - RAID56 - in case there's neither RAID5 nor RAID6 profile block group
799 * in the whole filesystem
800 *
801 * - RAID1C34 - same as above for RAID1C3 and RAID1C4 block groups
802 */
803static void clear_incompat_bg_bits(struct btrfs_fs_info *fs_info, u64 flags)
804{
805 bool found_raid56 = false;
806 bool found_raid1c34 = false;
807
808 if ((flags & BTRFS_BLOCK_GROUP_RAID56_MASK) ||
809 (flags & BTRFS_BLOCK_GROUP_RAID1C3) ||
810 (flags & BTRFS_BLOCK_GROUP_RAID1C4)) {
811 struct list_head *head = &fs_info->space_info;
812 struct btrfs_space_info *sinfo;
813
814 list_for_each_entry_rcu(sinfo, head, list) {
815 down_read(&sinfo->groups_sem);
816 if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID5]))
817 found_raid56 = true;
818 if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID6]))
819 found_raid56 = true;
820 if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID1C3]))
821 found_raid1c34 = true;
822 if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID1C4]))
823 found_raid1c34 = true;
824 up_read(&sinfo->groups_sem);
825 }
826 if (!found_raid56)
827 btrfs_clear_fs_incompat(fs_info, RAID56);
828 if (!found_raid1c34)
829 btrfs_clear_fs_incompat(fs_info, RAID1C34);
830 }
831}
832
833static int remove_block_group_item(struct btrfs_trans_handle *trans,
834 struct btrfs_path *path,
835 struct btrfs_block_group *block_group)
836{
837 struct btrfs_fs_info *fs_info = trans->fs_info;
838 struct btrfs_root *root;
839 struct btrfs_key key;
840 int ret;
841
842 root = fs_info->extent_root;
843 key.objectid = block_group->start;
844 key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
845 key.offset = block_group->length;
846
847 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
848 if (ret > 0)
849 ret = -ENOENT;
850 if (ret < 0)
851 return ret;
852
853 ret = btrfs_del_item(trans, root, path);
854 return ret;
855}
856
857int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
858 u64 group_start, struct extent_map *em)
859{
860 struct btrfs_fs_info *fs_info = trans->fs_info;
861 struct btrfs_path *path;
862 struct btrfs_block_group *block_group;
863 struct btrfs_free_cluster *cluster;
864 struct inode *inode;
865 struct kobject *kobj = NULL;
866 int ret;
867 int index;
868 int factor;
869 struct btrfs_caching_control *caching_ctl = NULL;
870 bool remove_em;
871 bool remove_rsv = false;
872
873 block_group = btrfs_lookup_block_group(fs_info, group_start);
874 BUG_ON(!block_group);
875 BUG_ON(!block_group->ro);
876
877 trace_btrfs_remove_block_group(block_group);
878 /*
879 * Free the reserved super bytes from this block group before
880 * remove it.
881 */
882 btrfs_free_excluded_extents(block_group);
883 btrfs_free_ref_tree_range(fs_info, block_group->start,
884 block_group->length);
885
886 index = btrfs_bg_flags_to_raid_index(block_group->flags);
887 factor = btrfs_bg_type_to_factor(block_group->flags);
888
889 /* make sure this block group isn't part of an allocation cluster */
890 cluster = &fs_info->data_alloc_cluster;
891 spin_lock(&cluster->refill_lock);
892 btrfs_return_cluster_to_free_space(block_group, cluster);
893 spin_unlock(&cluster->refill_lock);
894
895 /*
896 * make sure this block group isn't part of a metadata
897 * allocation cluster
898 */
899 cluster = &fs_info->meta_alloc_cluster;
900 spin_lock(&cluster->refill_lock);
901 btrfs_return_cluster_to_free_space(block_group, cluster);
902 spin_unlock(&cluster->refill_lock);
903
904 btrfs_clear_treelog_bg(block_group);
905
906 path = btrfs_alloc_path();
907 if (!path) {
908 ret = -ENOMEM;
909 goto out;
910 }
911
912 /*
913 * get the inode first so any iput calls done for the io_list
914 * aren't the final iput (no unlinks allowed now)
915 */
916 inode = lookup_free_space_inode(block_group, path);
917
918 mutex_lock(&trans->transaction->cache_write_mutex);
919 /*
920 * Make sure our free space cache IO is done before removing the
921 * free space inode
922 */
923 spin_lock(&trans->transaction->dirty_bgs_lock);
924 if (!list_empty(&block_group->io_list)) {
925 list_del_init(&block_group->io_list);
926
927 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
928
929 spin_unlock(&trans->transaction->dirty_bgs_lock);
930 btrfs_wait_cache_io(trans, block_group, path);
931 btrfs_put_block_group(block_group);
932 spin_lock(&trans->transaction->dirty_bgs_lock);
933 }
934
935 if (!list_empty(&block_group->dirty_list)) {
936 list_del_init(&block_group->dirty_list);
937 remove_rsv = true;
938 btrfs_put_block_group(block_group);
939 }
940 spin_unlock(&trans->transaction->dirty_bgs_lock);
941 mutex_unlock(&trans->transaction->cache_write_mutex);
942
943 ret = btrfs_remove_free_space_inode(trans, inode, block_group);
944 if (ret)
945 goto out;
946
947 spin_lock(&fs_info->block_group_cache_lock);
948 rb_erase(&block_group->cache_node,
949 &fs_info->block_group_cache_tree);
950 RB_CLEAR_NODE(&block_group->cache_node);
951
952 /* Once for the block groups rbtree */
953 btrfs_put_block_group(block_group);
954
955 if (fs_info->first_logical_byte == block_group->start)
956 fs_info->first_logical_byte = (u64)-1;
957 spin_unlock(&fs_info->block_group_cache_lock);
958
959 down_write(&block_group->space_info->groups_sem);
960 /*
961 * we must use list_del_init so people can check to see if they
962 * are still on the list after taking the semaphore
963 */
964 list_del_init(&block_group->list);
965 if (list_empty(&block_group->space_info->block_groups[index])) {
966 kobj = block_group->space_info->block_group_kobjs[index];
967 block_group->space_info->block_group_kobjs[index] = NULL;
968 clear_avail_alloc_bits(fs_info, block_group->flags);
969 }
970 up_write(&block_group->space_info->groups_sem);
971 clear_incompat_bg_bits(fs_info, block_group->flags);
972 if (kobj) {
973 kobject_del(kobj);
974 kobject_put(kobj);
975 }
976
977 if (block_group->has_caching_ctl)
978 caching_ctl = btrfs_get_caching_control(block_group);
979 if (block_group->cached == BTRFS_CACHE_STARTED)
980 btrfs_wait_block_group_cache_done(block_group);
981 if (block_group->has_caching_ctl) {
982 spin_lock(&fs_info->block_group_cache_lock);
983 if (!caching_ctl) {
984 struct btrfs_caching_control *ctl;
985
986 list_for_each_entry(ctl,
987 &fs_info->caching_block_groups, list)
988 if (ctl->block_group == block_group) {
989 caching_ctl = ctl;
990 refcount_inc(&caching_ctl->count);
991 break;
992 }
993 }
994 if (caching_ctl)
995 list_del_init(&caching_ctl->list);
996 spin_unlock(&fs_info->block_group_cache_lock);
997 if (caching_ctl) {
998 /* Once for the caching bgs list and once for us. */
999 btrfs_put_caching_control(caching_ctl);
1000 btrfs_put_caching_control(caching_ctl);
1001 }
1002 }
1003
1004 spin_lock(&trans->transaction->dirty_bgs_lock);
1005 WARN_ON(!list_empty(&block_group->dirty_list));
1006 WARN_ON(!list_empty(&block_group->io_list));
1007 spin_unlock(&trans->transaction->dirty_bgs_lock);
1008
1009 btrfs_remove_free_space_cache(block_group);
1010
1011 spin_lock(&block_group->space_info->lock);
1012 list_del_init(&block_group->ro_list);
1013
1014 if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
1015 WARN_ON(block_group->space_info->total_bytes
1016 < block_group->length);
1017 WARN_ON(block_group->space_info->bytes_readonly
1018 < block_group->length - block_group->zone_unusable);
1019 WARN_ON(block_group->space_info->bytes_zone_unusable
1020 < block_group->zone_unusable);
1021 WARN_ON(block_group->space_info->disk_total
1022 < block_group->length * factor);
1023 }
1024 block_group->space_info->total_bytes -= block_group->length;
1025 block_group->space_info->bytes_readonly -=
1026 (block_group->length - block_group->zone_unusable);
1027 block_group->space_info->bytes_zone_unusable -=
1028 block_group->zone_unusable;
1029 block_group->space_info->disk_total -= block_group->length * factor;
1030
1031 spin_unlock(&block_group->space_info->lock);
1032
1033 /*
1034 * Remove the free space for the block group from the free space tree
1035 * and the block group's item from the extent tree before marking the
1036 * block group as removed. This is to prevent races with tasks that
1037 * freeze and unfreeze a block group, this task and another task
1038 * allocating a new block group - the unfreeze task ends up removing
1039 * the block group's extent map before the task calling this function
1040 * deletes the block group item from the extent tree, allowing for
1041 * another task to attempt to create another block group with the same
1042 * item key (and failing with -EEXIST and a transaction abort).
1043 */
1044 ret = remove_block_group_free_space(trans, block_group);
1045 if (ret)
1046 goto out;
1047
1048 ret = remove_block_group_item(trans, path, block_group);
1049 if (ret < 0)
1050 goto out;
1051
1052 spin_lock(&block_group->lock);
1053 block_group->removed = 1;
1054 /*
1055 * At this point trimming or scrub can't start on this block group,
1056 * because we removed the block group from the rbtree
1057 * fs_info->block_group_cache_tree so no one can't find it anymore and
1058 * even if someone already got this block group before we removed it
1059 * from the rbtree, they have already incremented block_group->frozen -
1060 * if they didn't, for the trimming case they won't find any free space
1061 * entries because we already removed them all when we called
1062 * btrfs_remove_free_space_cache().
1063 *
1064 * And we must not remove the extent map from the fs_info->mapping_tree
1065 * to prevent the same logical address range and physical device space
1066 * ranges from being reused for a new block group. This is needed to
1067 * avoid races with trimming and scrub.
1068 *
1069 * An fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
1070 * completely transactionless, so while it is trimming a range the
1071 * currently running transaction might finish and a new one start,
1072 * allowing for new block groups to be created that can reuse the same
1073 * physical device locations unless we take this special care.
1074 *
1075 * There may also be an implicit trim operation if the file system
1076 * is mounted with -odiscard. The same protections must remain
1077 * in place until the extents have been discarded completely when
1078 * the transaction commit has completed.
1079 */
1080 remove_em = (atomic_read(&block_group->frozen) == 0);
1081 spin_unlock(&block_group->lock);
1082
1083 if (remove_em) {
1084 struct extent_map_tree *em_tree;
1085
1086 em_tree = &fs_info->mapping_tree;
1087 write_lock(&em_tree->lock);
1088 remove_extent_mapping(em_tree, em);
1089 write_unlock(&em_tree->lock);
1090 /* once for the tree */
1091 free_extent_map(em);
1092 }
1093
1094out:
1095 /* Once for the lookup reference */
1096 btrfs_put_block_group(block_group);
1097 if (remove_rsv)
1098 btrfs_delayed_refs_rsv_release(fs_info, 1);
1099 btrfs_free_path(path);
1100 return ret;
1101}
1102
1103struct btrfs_trans_handle *btrfs_start_trans_remove_block_group(
1104 struct btrfs_fs_info *fs_info, const u64 chunk_offset)
1105{
1106 struct extent_map_tree *em_tree = &fs_info->mapping_tree;
1107 struct extent_map *em;
1108 struct map_lookup *map;
1109 unsigned int num_items;
1110
1111 read_lock(&em_tree->lock);
1112 em = lookup_extent_mapping(em_tree, chunk_offset, 1);
1113 read_unlock(&em_tree->lock);
1114 ASSERT(em && em->start == chunk_offset);
1115
1116 /*
1117 * We need to reserve 3 + N units from the metadata space info in order
1118 * to remove a block group (done at btrfs_remove_chunk() and at
1119 * btrfs_remove_block_group()), which are used for:
1120 *
1121 * 1 unit for adding the free space inode's orphan (located in the tree
1122 * of tree roots).
1123 * 1 unit for deleting the block group item (located in the extent
1124 * tree).
1125 * 1 unit for deleting the free space item (located in tree of tree
1126 * roots).
1127 * N units for deleting N device extent items corresponding to each
1128 * stripe (located in the device tree).
1129 *
1130 * In order to remove a block group we also need to reserve units in the
1131 * system space info in order to update the chunk tree (update one or
1132 * more device items and remove one chunk item), but this is done at
1133 * btrfs_remove_chunk() through a call to check_system_chunk().
1134 */
1135 map = em->map_lookup;
1136 num_items = 3 + map->num_stripes;
1137 free_extent_map(em);
1138
1139 return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
1140 num_items);
1141}
1142
1143/*
1144 * Mark block group @cache read-only, so later write won't happen to block
1145 * group @cache.
1146 *
1147 * If @force is not set, this function will only mark the block group readonly
1148 * if we have enough free space (1M) in other metadata/system block groups.
1149 * If @force is not set, this function will mark the block group readonly
1150 * without checking free space.
1151 *
1152 * NOTE: This function doesn't care if other block groups can contain all the
1153 * data in this block group. That check should be done by relocation routine,
1154 * not this function.
1155 */
1156static int inc_block_group_ro(struct btrfs_block_group *cache, int force)
1157{
1158 struct btrfs_space_info *sinfo = cache->space_info;
1159 u64 num_bytes;
1160 int ret = -ENOSPC;
1161
1162 spin_lock(&sinfo->lock);
1163 spin_lock(&cache->lock);
1164
1165 if (cache->swap_extents) {
1166 ret = -ETXTBSY;
1167 goto out;
1168 }
1169
1170 if (cache->ro) {
1171 cache->ro++;
1172 ret = 0;
1173 goto out;
1174 }
1175
1176 num_bytes = cache->length - cache->reserved - cache->pinned -
1177 cache->bytes_super - cache->zone_unusable - cache->used;
1178
1179 /*
1180 * Data never overcommits, even in mixed mode, so do just the straight
1181 * check of left over space in how much we have allocated.
1182 */
1183 if (force) {
1184 ret = 0;
1185 } else if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA) {
1186 u64 sinfo_used = btrfs_space_info_used(sinfo, true);
1187
1188 /*
1189 * Here we make sure if we mark this bg RO, we still have enough
1190 * free space as buffer.
1191 */
1192 if (sinfo_used + num_bytes <= sinfo->total_bytes)
1193 ret = 0;
1194 } else {
1195 /*
1196 * We overcommit metadata, so we need to do the
1197 * btrfs_can_overcommit check here, and we need to pass in
1198 * BTRFS_RESERVE_NO_FLUSH to give ourselves the most amount of
1199 * leeway to allow us to mark this block group as read only.
1200 */
1201 if (btrfs_can_overcommit(cache->fs_info, sinfo, num_bytes,
1202 BTRFS_RESERVE_NO_FLUSH))
1203 ret = 0;
1204 }
1205
1206 if (!ret) {
1207 sinfo->bytes_readonly += num_bytes;
1208 if (btrfs_is_zoned(cache->fs_info)) {
1209 /* Migrate zone_unusable bytes to readonly */
1210 sinfo->bytes_readonly += cache->zone_unusable;
1211 sinfo->bytes_zone_unusable -= cache->zone_unusable;
1212 cache->zone_unusable = 0;
1213 }
1214 cache->ro++;
1215 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
1216 }
1217out:
1218 spin_unlock(&cache->lock);
1219 spin_unlock(&sinfo->lock);
1220 if (ret == -ENOSPC && btrfs_test_opt(cache->fs_info, ENOSPC_DEBUG)) {
1221 btrfs_info(cache->fs_info,
1222 "unable to make block group %llu ro", cache->start);
1223 btrfs_dump_space_info(cache->fs_info, cache->space_info, 0, 0);
1224 }
1225 return ret;
1226}
1227
1228static bool clean_pinned_extents(struct btrfs_trans_handle *trans,
1229 struct btrfs_block_group *bg)
1230{
1231 struct btrfs_fs_info *fs_info = bg->fs_info;
1232 struct btrfs_transaction *prev_trans = NULL;
1233 const u64 start = bg->start;
1234 const u64 end = start + bg->length - 1;
1235 int ret;
1236
1237 spin_lock(&fs_info->trans_lock);
1238 if (trans->transaction->list.prev != &fs_info->trans_list) {
1239 prev_trans = list_last_entry(&trans->transaction->list,
1240 struct btrfs_transaction, list);
1241 refcount_inc(&prev_trans->use_count);
1242 }
1243 spin_unlock(&fs_info->trans_lock);
1244
1245 /*
1246 * Hold the unused_bg_unpin_mutex lock to avoid racing with
1247 * btrfs_finish_extent_commit(). If we are at transaction N, another
1248 * task might be running finish_extent_commit() for the previous
1249 * transaction N - 1, and have seen a range belonging to the block
1250 * group in pinned_extents before we were able to clear the whole block
1251 * group range from pinned_extents. This means that task can lookup for
1252 * the block group after we unpinned it from pinned_extents and removed
1253 * it, leading to a BUG_ON() at unpin_extent_range().
1254 */
1255 mutex_lock(&fs_info->unused_bg_unpin_mutex);
1256 if (prev_trans) {
1257 ret = clear_extent_bits(&prev_trans->pinned_extents, start, end,
1258 EXTENT_DIRTY);
1259 if (ret)
1260 goto out;
1261 }
1262
1263 ret = clear_extent_bits(&trans->transaction->pinned_extents, start, end,
1264 EXTENT_DIRTY);
1265out:
1266 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
1267 if (prev_trans)
1268 btrfs_put_transaction(prev_trans);
1269
1270 return ret == 0;
1271}
1272
1273/*
1274 * Process the unused_bgs list and remove any that don't have any allocated
1275 * space inside of them.
1276 */
1277void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
1278{
1279 struct btrfs_block_group *block_group;
1280 struct btrfs_space_info *space_info;
1281 struct btrfs_trans_handle *trans;
1282 const bool async_trim_enabled = btrfs_test_opt(fs_info, DISCARD_ASYNC);
1283 int ret = 0;
1284
1285 if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
1286 return;
1287
1288 /*
1289 * Long running balances can keep us blocked here for eternity, so
1290 * simply skip deletion if we're unable to get the mutex.
1291 */
1292 if (!mutex_trylock(&fs_info->reclaim_bgs_lock))
1293 return;
1294
1295 spin_lock(&fs_info->unused_bgs_lock);
1296 while (!list_empty(&fs_info->unused_bgs)) {
1297 int trimming;
1298
1299 block_group = list_first_entry(&fs_info->unused_bgs,
1300 struct btrfs_block_group,
1301 bg_list);
1302 list_del_init(&block_group->bg_list);
1303
1304 space_info = block_group->space_info;
1305
1306 if (ret || btrfs_mixed_space_info(space_info)) {
1307 btrfs_put_block_group(block_group);
1308 continue;
1309 }
1310 spin_unlock(&fs_info->unused_bgs_lock);
1311
1312 btrfs_discard_cancel_work(&fs_info->discard_ctl, block_group);
1313
1314 /* Don't want to race with allocators so take the groups_sem */
1315 down_write(&space_info->groups_sem);
1316
1317 /*
1318 * Async discard moves the final block group discard to be prior
1319 * to the unused_bgs code path. Therefore, if it's not fully
1320 * trimmed, punt it back to the async discard lists.
1321 */
1322 if (btrfs_test_opt(fs_info, DISCARD_ASYNC) &&
1323 !btrfs_is_free_space_trimmed(block_group)) {
1324 trace_btrfs_skip_unused_block_group(block_group);
1325 up_write(&space_info->groups_sem);
1326 /* Requeue if we failed because of async discard */
1327 btrfs_discard_queue_work(&fs_info->discard_ctl,
1328 block_group);
1329 goto next;
1330 }
1331
1332 spin_lock(&block_group->lock);
1333 if (block_group->reserved || block_group->pinned ||
1334 block_group->used || block_group->ro ||
1335 list_is_singular(&block_group->list)) {
1336 /*
1337 * We want to bail if we made new allocations or have
1338 * outstanding allocations in this block group. We do
1339 * the ro check in case balance is currently acting on
1340 * this block group.
1341 */
1342 trace_btrfs_skip_unused_block_group(block_group);
1343 spin_unlock(&block_group->lock);
1344 up_write(&space_info->groups_sem);
1345 goto next;
1346 }
1347 spin_unlock(&block_group->lock);
1348
1349 /* We don't want to force the issue, only flip if it's ok. */
1350 ret = inc_block_group_ro(block_group, 0);
1351 up_write(&space_info->groups_sem);
1352 if (ret < 0) {
1353 ret = 0;
1354 goto next;
1355 }
1356
1357 /*
1358 * Want to do this before we do anything else so we can recover
1359 * properly if we fail to join the transaction.
1360 */
1361 trans = btrfs_start_trans_remove_block_group(fs_info,
1362 block_group->start);
1363 if (IS_ERR(trans)) {
1364 btrfs_dec_block_group_ro(block_group);
1365 ret = PTR_ERR(trans);
1366 goto next;
1367 }
1368
1369 /*
1370 * We could have pending pinned extents for this block group,
1371 * just delete them, we don't care about them anymore.
1372 */
1373 if (!clean_pinned_extents(trans, block_group)) {
1374 btrfs_dec_block_group_ro(block_group);
1375 goto end_trans;
1376 }
1377
1378 /*
1379 * At this point, the block_group is read only and should fail
1380 * new allocations. However, btrfs_finish_extent_commit() can
1381 * cause this block_group to be placed back on the discard
1382 * lists because now the block_group isn't fully discarded.
1383 * Bail here and try again later after discarding everything.
1384 */
1385 spin_lock(&fs_info->discard_ctl.lock);
1386 if (!list_empty(&block_group->discard_list)) {
1387 spin_unlock(&fs_info->discard_ctl.lock);
1388 btrfs_dec_block_group_ro(block_group);
1389 btrfs_discard_queue_work(&fs_info->discard_ctl,
1390 block_group);
1391 goto end_trans;
1392 }
1393 spin_unlock(&fs_info->discard_ctl.lock);
1394
1395 /* Reset pinned so btrfs_put_block_group doesn't complain */
1396 spin_lock(&space_info->lock);
1397 spin_lock(&block_group->lock);
1398
1399 btrfs_space_info_update_bytes_pinned(fs_info, space_info,
1400 -block_group->pinned);
1401 space_info->bytes_readonly += block_group->pinned;
1402 block_group->pinned = 0;
1403
1404 spin_unlock(&block_group->lock);
1405 spin_unlock(&space_info->lock);
1406
1407 /*
1408 * The normal path here is an unused block group is passed here,
1409 * then trimming is handled in the transaction commit path.
1410 * Async discard interposes before this to do the trimming
1411 * before coming down the unused block group path as trimming
1412 * will no longer be done later in the transaction commit path.
1413 */
1414 if (!async_trim_enabled && btrfs_test_opt(fs_info, DISCARD_ASYNC))
1415 goto flip_async;
1416
1417 /*
1418 * DISCARD can flip during remount. On zoned filesystems, we
1419 * need to reset sequential-required zones.
1420 */
1421 trimming = btrfs_test_opt(fs_info, DISCARD_SYNC) ||
1422 btrfs_is_zoned(fs_info);
1423
1424 /* Implicit trim during transaction commit. */
1425 if (trimming)
1426 btrfs_freeze_block_group(block_group);
1427
1428 /*
1429 * Btrfs_remove_chunk will abort the transaction if things go
1430 * horribly wrong.
1431 */
1432 ret = btrfs_remove_chunk(trans, block_group->start);
1433
1434 if (ret) {
1435 if (trimming)
1436 btrfs_unfreeze_block_group(block_group);
1437 goto end_trans;
1438 }
1439
1440 /*
1441 * If we're not mounted with -odiscard, we can just forget
1442 * about this block group. Otherwise we'll need to wait
1443 * until transaction commit to do the actual discard.
1444 */
1445 if (trimming) {
1446 spin_lock(&fs_info->unused_bgs_lock);
1447 /*
1448 * A concurrent scrub might have added us to the list
1449 * fs_info->unused_bgs, so use a list_move operation
1450 * to add the block group to the deleted_bgs list.
1451 */
1452 list_move(&block_group->bg_list,
1453 &trans->transaction->deleted_bgs);
1454 spin_unlock(&fs_info->unused_bgs_lock);
1455 btrfs_get_block_group(block_group);
1456 }
1457end_trans:
1458 btrfs_end_transaction(trans);
1459next:
1460 btrfs_put_block_group(block_group);
1461 spin_lock(&fs_info->unused_bgs_lock);
1462 }
1463 spin_unlock(&fs_info->unused_bgs_lock);
1464 mutex_unlock(&fs_info->reclaim_bgs_lock);
1465 return;
1466
1467flip_async:
1468 btrfs_end_transaction(trans);
1469 mutex_unlock(&fs_info->reclaim_bgs_lock);
1470 btrfs_put_block_group(block_group);
1471 btrfs_discard_punt_unused_bgs_list(fs_info);
1472}
1473
1474void btrfs_mark_bg_unused(struct btrfs_block_group *bg)
1475{
1476 struct btrfs_fs_info *fs_info = bg->fs_info;
1477
1478 spin_lock(&fs_info->unused_bgs_lock);
1479 if (list_empty(&bg->bg_list)) {
1480 btrfs_get_block_group(bg);
1481 trace_btrfs_add_unused_block_group(bg);
1482 list_add_tail(&bg->bg_list, &fs_info->unused_bgs);
1483 }
1484 spin_unlock(&fs_info->unused_bgs_lock);
1485}
1486
1487void btrfs_reclaim_bgs_work(struct work_struct *work)
1488{
1489 struct btrfs_fs_info *fs_info =
1490 container_of(work, struct btrfs_fs_info, reclaim_bgs_work);
1491 struct btrfs_block_group *bg;
1492 struct btrfs_space_info *space_info;
1493 LIST_HEAD(again_list);
1494
1495 if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
1496 return;
1497
1498 if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_BALANCE))
1499 return;
1500
1501 /*
1502 * Long running balances can keep us blocked here for eternity, so
1503 * simply skip reclaim if we're unable to get the mutex.
1504 */
1505 if (!mutex_trylock(&fs_info->reclaim_bgs_lock)) {
1506 btrfs_exclop_finish(fs_info);
1507 return;
1508 }
1509
1510 spin_lock(&fs_info->unused_bgs_lock);
1511 while (!list_empty(&fs_info->reclaim_bgs)) {
1512 u64 zone_unusable;
1513 int ret = 0;
1514
1515 bg = list_first_entry(&fs_info->reclaim_bgs,
1516 struct btrfs_block_group,
1517 bg_list);
1518 list_del_init(&bg->bg_list);
1519
1520 space_info = bg->space_info;
1521 spin_unlock(&fs_info->unused_bgs_lock);
1522
1523 /* Don't race with allocators so take the groups_sem */
1524 down_write(&space_info->groups_sem);
1525
1526 spin_lock(&bg->lock);
1527 if (bg->reserved || bg->pinned || bg->ro) {
1528 /*
1529 * We want to bail if we made new allocations or have
1530 * outstanding allocations in this block group. We do
1531 * the ro check in case balance is currently acting on
1532 * this block group.
1533 */
1534 spin_unlock(&bg->lock);
1535 up_write(&space_info->groups_sem);
1536 goto next;
1537 }
1538 spin_unlock(&bg->lock);
1539
1540 /* Get out fast, in case we're unmounting the filesystem */
1541 if (btrfs_fs_closing(fs_info)) {
1542 up_write(&space_info->groups_sem);
1543 goto next;
1544 }
1545
1546 /*
1547 * Cache the zone_unusable value before turning the block group
1548 * to read only. As soon as the blog group is read only it's
1549 * zone_unusable value gets moved to the block group's read-only
1550 * bytes and isn't available for calculations anymore.
1551 */
1552 zone_unusable = bg->zone_unusable;
1553 ret = inc_block_group_ro(bg, 0);
1554 up_write(&space_info->groups_sem);
1555 if (ret < 0)
1556 goto next;
1557
1558 btrfs_info(fs_info,
1559 "reclaiming chunk %llu with %llu%% used %llu%% unusable",
1560 bg->start, div_u64(bg->used * 100, bg->length),
1561 div64_u64(zone_unusable * 100, bg->length));
1562 trace_btrfs_reclaim_block_group(bg);
1563 ret = btrfs_relocate_chunk(fs_info, bg->start);
1564 if (ret && ret != -EAGAIN)
1565 btrfs_err(fs_info, "error relocating chunk %llu",
1566 bg->start);
1567
1568next:
1569 spin_lock(&fs_info->unused_bgs_lock);
1570 if (ret == -EAGAIN && list_empty(&bg->bg_list))
1571 list_add_tail(&bg->bg_list, &again_list);
1572 else
1573 btrfs_put_block_group(bg);
1574 }
1575 list_splice_tail(&again_list, &fs_info->reclaim_bgs);
1576 spin_unlock(&fs_info->unused_bgs_lock);
1577 mutex_unlock(&fs_info->reclaim_bgs_lock);
1578 btrfs_exclop_finish(fs_info);
1579}
1580
1581void btrfs_reclaim_bgs(struct btrfs_fs_info *fs_info)
1582{
1583 spin_lock(&fs_info->unused_bgs_lock);
1584 if (!list_empty(&fs_info->reclaim_bgs))
1585 queue_work(system_unbound_wq, &fs_info->reclaim_bgs_work);
1586 spin_unlock(&fs_info->unused_bgs_lock);
1587}
1588
1589void btrfs_mark_bg_to_reclaim(struct btrfs_block_group *bg)
1590{
1591 struct btrfs_fs_info *fs_info = bg->fs_info;
1592
1593 spin_lock(&fs_info->unused_bgs_lock);
1594 if (list_empty(&bg->bg_list)) {
1595 btrfs_get_block_group(bg);
1596 trace_btrfs_add_reclaim_block_group(bg);
1597 list_add_tail(&bg->bg_list, &fs_info->reclaim_bgs);
1598 }
1599 spin_unlock(&fs_info->unused_bgs_lock);
1600}
1601
1602static int read_bg_from_eb(struct btrfs_fs_info *fs_info, struct btrfs_key *key,
1603 struct btrfs_path *path)
1604{
1605 struct extent_map_tree *em_tree;
1606 struct extent_map *em;
1607 struct btrfs_block_group_item bg;
1608 struct extent_buffer *leaf;
1609 int slot;
1610 u64 flags;
1611 int ret = 0;
1612
1613 slot = path->slots[0];
1614 leaf = path->nodes[0];
1615
1616 em_tree = &fs_info->mapping_tree;
1617 read_lock(&em_tree->lock);
1618 em = lookup_extent_mapping(em_tree, key->objectid, key->offset);
1619 read_unlock(&em_tree->lock);
1620 if (!em) {
1621 btrfs_err(fs_info,
1622 "logical %llu len %llu found bg but no related chunk",
1623 key->objectid, key->offset);
1624 return -ENOENT;
1625 }
1626
1627 if (em->start != key->objectid || em->len != key->offset) {
1628 btrfs_err(fs_info,
1629 "block group %llu len %llu mismatch with chunk %llu len %llu",
1630 key->objectid, key->offset, em->start, em->len);
1631 ret = -EUCLEAN;
1632 goto out_free_em;
1633 }
1634
1635 read_extent_buffer(leaf, &bg, btrfs_item_ptr_offset(leaf, slot),
1636 sizeof(bg));
1637 flags = btrfs_stack_block_group_flags(&bg) &
1638 BTRFS_BLOCK_GROUP_TYPE_MASK;
1639
1640 if (flags != (em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK)) {
1641 btrfs_err(fs_info,
1642"block group %llu len %llu type flags 0x%llx mismatch with chunk type flags 0x%llx",
1643 key->objectid, key->offset, flags,
1644 (BTRFS_BLOCK_GROUP_TYPE_MASK & em->map_lookup->type));
1645 ret = -EUCLEAN;
1646 }
1647
1648out_free_em:
1649 free_extent_map(em);
1650 return ret;
1651}
1652
1653static int find_first_block_group(struct btrfs_fs_info *fs_info,
1654 struct btrfs_path *path,
1655 struct btrfs_key *key)
1656{
1657 struct btrfs_root *root = fs_info->extent_root;
1658 int ret;
1659 struct btrfs_key found_key;
1660 struct extent_buffer *leaf;
1661 int slot;
1662
1663 ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
1664 if (ret < 0)
1665 return ret;
1666
1667 while (1) {
1668 slot = path->slots[0];
1669 leaf = path->nodes[0];
1670 if (slot >= btrfs_header_nritems(leaf)) {
1671 ret = btrfs_next_leaf(root, path);
1672 if (ret == 0)
1673 continue;
1674 if (ret < 0)
1675 goto out;
1676 break;
1677 }
1678 btrfs_item_key_to_cpu(leaf, &found_key, slot);
1679
1680 if (found_key.objectid >= key->objectid &&
1681 found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
1682 ret = read_bg_from_eb(fs_info, &found_key, path);
1683 break;
1684 }
1685
1686 path->slots[0]++;
1687 }
1688out:
1689 return ret;
1690}
1691
1692static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
1693{
1694 u64 extra_flags = chunk_to_extended(flags) &
1695 BTRFS_EXTENDED_PROFILE_MASK;
1696
1697 write_seqlock(&fs_info->profiles_lock);
1698 if (flags & BTRFS_BLOCK_GROUP_DATA)
1699 fs_info->avail_data_alloc_bits |= extra_flags;
1700 if (flags & BTRFS_BLOCK_GROUP_METADATA)
1701 fs_info->avail_metadata_alloc_bits |= extra_flags;
1702 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
1703 fs_info->avail_system_alloc_bits |= extra_flags;
1704 write_sequnlock(&fs_info->profiles_lock);
1705}
1706
1707/**
1708 * Map a physical disk address to a list of logical addresses
1709 *
1710 * @fs_info: the filesystem
1711 * @chunk_start: logical address of block group
1712 * @bdev: physical device to resolve, can be NULL to indicate any device
1713 * @physical: physical address to map to logical addresses
1714 * @logical: return array of logical addresses which map to @physical
1715 * @naddrs: length of @logical
1716 * @stripe_len: size of IO stripe for the given block group
1717 *
1718 * Maps a particular @physical disk address to a list of @logical addresses.
1719 * Used primarily to exclude those portions of a block group that contain super
1720 * block copies.
1721 */
1722int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
1723 struct block_device *bdev, u64 physical, u64 **logical,
1724 int *naddrs, int *stripe_len)
1725{
1726 struct extent_map *em;
1727 struct map_lookup *map;
1728 u64 *buf;
1729 u64 bytenr;
1730 u64 data_stripe_length;
1731 u64 io_stripe_size;
1732 int i, nr = 0;
1733 int ret = 0;
1734
1735 em = btrfs_get_chunk_map(fs_info, chunk_start, 1);
1736 if (IS_ERR(em))
1737 return -EIO;
1738
1739 map = em->map_lookup;
1740 data_stripe_length = em->orig_block_len;
1741 io_stripe_size = map->stripe_len;
1742 chunk_start = em->start;
1743
1744 /* For RAID5/6 adjust to a full IO stripe length */
1745 if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
1746 io_stripe_size = map->stripe_len * nr_data_stripes(map);
1747
1748 buf = kcalloc(map->num_stripes, sizeof(u64), GFP_NOFS);
1749 if (!buf) {
1750 ret = -ENOMEM;
1751 goto out;
1752 }
1753
1754 for (i = 0; i < map->num_stripes; i++) {
1755 bool already_inserted = false;
1756 u64 stripe_nr;
1757 u64 offset;
1758 int j;
1759
1760 if (!in_range(physical, map->stripes[i].physical,
1761 data_stripe_length))
1762 continue;
1763
1764 if (bdev && map->stripes[i].dev->bdev != bdev)
1765 continue;
1766
1767 stripe_nr = physical - map->stripes[i].physical;
1768 stripe_nr = div64_u64_rem(stripe_nr, map->stripe_len, &offset);
1769
1770 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
1771 stripe_nr = stripe_nr * map->num_stripes + i;
1772 stripe_nr = div_u64(stripe_nr, map->sub_stripes);
1773 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
1774 stripe_nr = stripe_nr * map->num_stripes + i;
1775 }
1776 /*
1777 * The remaining case would be for RAID56, multiply by
1778 * nr_data_stripes(). Alternatively, just use rmap_len below
1779 * instead of map->stripe_len
1780 */
1781
1782 bytenr = chunk_start + stripe_nr * io_stripe_size + offset;
1783
1784 /* Ensure we don't add duplicate addresses */
1785 for (j = 0; j < nr; j++) {
1786 if (buf[j] == bytenr) {
1787 already_inserted = true;
1788 break;
1789 }
1790 }
1791
1792 if (!already_inserted)
1793 buf[nr++] = bytenr;
1794 }
1795
1796 *logical = buf;
1797 *naddrs = nr;
1798 *stripe_len = io_stripe_size;
1799out:
1800 free_extent_map(em);
1801 return ret;
1802}
1803
1804static int exclude_super_stripes(struct btrfs_block_group *cache)
1805{
1806 struct btrfs_fs_info *fs_info = cache->fs_info;
1807 const bool zoned = btrfs_is_zoned(fs_info);
1808 u64 bytenr;
1809 u64 *logical;
1810 int stripe_len;
1811 int i, nr, ret;
1812
1813 if (cache->start < BTRFS_SUPER_INFO_OFFSET) {
1814 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->start;
1815 cache->bytes_super += stripe_len;
1816 ret = btrfs_add_excluded_extent(fs_info, cache->start,
1817 stripe_len);
1818 if (ret)
1819 return ret;
1820 }
1821
1822 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
1823 bytenr = btrfs_sb_offset(i);
1824 ret = btrfs_rmap_block(fs_info, cache->start, NULL,
1825 bytenr, &logical, &nr, &stripe_len);
1826 if (ret)
1827 return ret;
1828
1829 /* Shouldn't have super stripes in sequential zones */
1830 if (zoned && nr) {
1831 btrfs_err(fs_info,
1832 "zoned: block group %llu must not contain super block",
1833 cache->start);
1834 return -EUCLEAN;
1835 }
1836
1837 while (nr--) {
1838 u64 len = min_t(u64, stripe_len,
1839 cache->start + cache->length - logical[nr]);
1840
1841 cache->bytes_super += len;
1842 ret = btrfs_add_excluded_extent(fs_info, logical[nr],
1843 len);
1844 if (ret) {
1845 kfree(logical);
1846 return ret;
1847 }
1848 }
1849
1850 kfree(logical);
1851 }
1852 return 0;
1853}
1854
1855static void link_block_group(struct btrfs_block_group *cache)
1856{
1857 struct btrfs_space_info *space_info = cache->space_info;
1858 int index = btrfs_bg_flags_to_raid_index(cache->flags);
1859
1860 down_write(&space_info->groups_sem);
1861 list_add_tail(&cache->list, &space_info->block_groups[index]);
1862 up_write(&space_info->groups_sem);
1863}
1864
1865static struct btrfs_block_group *btrfs_create_block_group_cache(
1866 struct btrfs_fs_info *fs_info, u64 start)
1867{
1868 struct btrfs_block_group *cache;
1869
1870 cache = kzalloc(sizeof(*cache), GFP_NOFS);
1871 if (!cache)
1872 return NULL;
1873
1874 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
1875 GFP_NOFS);
1876 if (!cache->free_space_ctl) {
1877 kfree(cache);
1878 return NULL;
1879 }
1880
1881 cache->start = start;
1882
1883 cache->fs_info = fs_info;
1884 cache->full_stripe_len = btrfs_full_stripe_len(fs_info, start);
1885
1886 cache->discard_index = BTRFS_DISCARD_INDEX_UNUSED;
1887
1888 refcount_set(&cache->refs, 1);
1889 spin_lock_init(&cache->lock);
1890 init_rwsem(&cache->data_rwsem);
1891 INIT_LIST_HEAD(&cache->list);
1892 INIT_LIST_HEAD(&cache->cluster_list);
1893 INIT_LIST_HEAD(&cache->bg_list);
1894 INIT_LIST_HEAD(&cache->ro_list);
1895 INIT_LIST_HEAD(&cache->discard_list);
1896 INIT_LIST_HEAD(&cache->dirty_list);
1897 INIT_LIST_HEAD(&cache->io_list);
1898 btrfs_init_free_space_ctl(cache, cache->free_space_ctl);
1899 atomic_set(&cache->frozen, 0);
1900 mutex_init(&cache->free_space_lock);
1901 btrfs_init_full_stripe_locks_tree(&cache->full_stripe_locks_root);
1902
1903 return cache;
1904}
1905
1906/*
1907 * Iterate all chunks and verify that each of them has the corresponding block
1908 * group
1909 */
1910static int check_chunk_block_group_mappings(struct btrfs_fs_info *fs_info)
1911{
1912 struct extent_map_tree *map_tree = &fs_info->mapping_tree;
1913 struct extent_map *em;
1914 struct btrfs_block_group *bg;
1915 u64 start = 0;
1916 int ret = 0;
1917
1918 while (1) {
1919 read_lock(&map_tree->lock);
1920 /*
1921 * lookup_extent_mapping will return the first extent map
1922 * intersecting the range, so setting @len to 1 is enough to
1923 * get the first chunk.
1924 */
1925 em = lookup_extent_mapping(map_tree, start, 1);
1926 read_unlock(&map_tree->lock);
1927 if (!em)
1928 break;
1929
1930 bg = btrfs_lookup_block_group(fs_info, em->start);
1931 if (!bg) {
1932 btrfs_err(fs_info,
1933 "chunk start=%llu len=%llu doesn't have corresponding block group",
1934 em->start, em->len);
1935 ret = -EUCLEAN;
1936 free_extent_map(em);
1937 break;
1938 }
1939 if (bg->start != em->start || bg->length != em->len ||
1940 (bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK) !=
1941 (em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK)) {
1942 btrfs_err(fs_info,
1943"chunk start=%llu len=%llu flags=0x%llx doesn't match block group start=%llu len=%llu flags=0x%llx",
1944 em->start, em->len,
1945 em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK,
1946 bg->start, bg->length,
1947 bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK);
1948 ret = -EUCLEAN;
1949 free_extent_map(em);
1950 btrfs_put_block_group(bg);
1951 break;
1952 }
1953 start = em->start + em->len;
1954 free_extent_map(em);
1955 btrfs_put_block_group(bg);
1956 }
1957 return ret;
1958}
1959
1960static int read_one_block_group(struct btrfs_fs_info *info,
1961 struct btrfs_block_group_item *bgi,
1962 const struct btrfs_key *key,
1963 int need_clear)
1964{
1965 struct btrfs_block_group *cache;
1966 struct btrfs_space_info *space_info;
1967 const bool mixed = btrfs_fs_incompat(info, MIXED_GROUPS);
1968 int ret;
1969
1970 ASSERT(key->type == BTRFS_BLOCK_GROUP_ITEM_KEY);
1971
1972 cache = btrfs_create_block_group_cache(info, key->objectid);
1973 if (!cache)
1974 return -ENOMEM;
1975
1976 cache->length = key->offset;
1977 cache->used = btrfs_stack_block_group_used(bgi);
1978 cache->flags = btrfs_stack_block_group_flags(bgi);
1979
1980 set_free_space_tree_thresholds(cache);
1981
1982 if (need_clear) {
1983 /*
1984 * When we mount with old space cache, we need to
1985 * set BTRFS_DC_CLEAR and set dirty flag.
1986 *
1987 * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
1988 * truncate the old free space cache inode and
1989 * setup a new one.
1990 * b) Setting 'dirty flag' makes sure that we flush
1991 * the new space cache info onto disk.
1992 */
1993 if (btrfs_test_opt(info, SPACE_CACHE))
1994 cache->disk_cache_state = BTRFS_DC_CLEAR;
1995 }
1996 if (!mixed && ((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
1997 (cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
1998 btrfs_err(info,
1999"bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
2000 cache->start);
2001 ret = -EINVAL;
2002 goto error;
2003 }
2004
2005 ret = btrfs_load_block_group_zone_info(cache, false);
2006 if (ret) {
2007 btrfs_err(info, "zoned: failed to load zone info of bg %llu",
2008 cache->start);
2009 goto error;
2010 }
2011
2012 /*
2013 * We need to exclude the super stripes now so that the space info has
2014 * super bytes accounted for, otherwise we'll think we have more space
2015 * than we actually do.
2016 */
2017 ret = exclude_super_stripes(cache);
2018 if (ret) {
2019 /* We may have excluded something, so call this just in case. */
2020 btrfs_free_excluded_extents(cache);
2021 goto error;
2022 }
2023
2024 /*
2025 * For zoned filesystem, space after the allocation offset is the only
2026 * free space for a block group. So, we don't need any caching work.
2027 * btrfs_calc_zone_unusable() will set the amount of free space and
2028 * zone_unusable space.
2029 *
2030 * For regular filesystem, check for two cases, either we are full, and
2031 * therefore don't need to bother with the caching work since we won't
2032 * find any space, or we are empty, and we can just add all the space
2033 * in and be done with it. This saves us _a_lot_ of time, particularly
2034 * in the full case.
2035 */
2036 if (btrfs_is_zoned(info)) {
2037 btrfs_calc_zone_unusable(cache);
2038 } else if (cache->length == cache->used) {
2039 cache->last_byte_to_unpin = (u64)-1;
2040 cache->cached = BTRFS_CACHE_FINISHED;
2041 btrfs_free_excluded_extents(cache);
2042 } else if (cache->used == 0) {
2043 cache->last_byte_to_unpin = (u64)-1;
2044 cache->cached = BTRFS_CACHE_FINISHED;
2045 add_new_free_space(cache, cache->start,
2046 cache->start + cache->length);
2047 btrfs_free_excluded_extents(cache);
2048 }
2049
2050 ret = btrfs_add_block_group_cache(info, cache);
2051 if (ret) {
2052 btrfs_remove_free_space_cache(cache);
2053 goto error;
2054 }
2055 trace_btrfs_add_block_group(info, cache, 0);
2056 btrfs_update_space_info(info, cache->flags, cache->length,
2057 cache->used, cache->bytes_super,
2058 cache->zone_unusable, &space_info);
2059
2060 cache->space_info = space_info;
2061
2062 link_block_group(cache);
2063
2064 set_avail_alloc_bits(info, cache->flags);
2065 if (btrfs_chunk_readonly(info, cache->start)) {
2066 inc_block_group_ro(cache, 1);
2067 } else if (cache->used == 0) {
2068 ASSERT(list_empty(&cache->bg_list));
2069 if (btrfs_test_opt(info, DISCARD_ASYNC))
2070 btrfs_discard_queue_work(&info->discard_ctl, cache);
2071 else
2072 btrfs_mark_bg_unused(cache);
2073 }
2074 return 0;
2075error:
2076 btrfs_put_block_group(cache);
2077 return ret;
2078}
2079
2080static int fill_dummy_bgs(struct btrfs_fs_info *fs_info)
2081{
2082 struct extent_map_tree *em_tree = &fs_info->mapping_tree;
2083 struct btrfs_space_info *space_info;
2084 struct rb_node *node;
2085 int ret = 0;
2086
2087 for (node = rb_first_cached(&em_tree->map); node; node = rb_next(node)) {
2088 struct extent_map *em;
2089 struct map_lookup *map;
2090 struct btrfs_block_group *bg;
2091
2092 em = rb_entry(node, struct extent_map, rb_node);
2093 map = em->map_lookup;
2094 bg = btrfs_create_block_group_cache(fs_info, em->start);
2095 if (!bg) {
2096 ret = -ENOMEM;
2097 break;
2098 }
2099
2100 /* Fill dummy cache as FULL */
2101 bg->length = em->len;
2102 bg->flags = map->type;
2103 bg->last_byte_to_unpin = (u64)-1;
2104 bg->cached = BTRFS_CACHE_FINISHED;
2105 bg->used = em->len;
2106 bg->flags = map->type;
2107 ret = btrfs_add_block_group_cache(fs_info, bg);
2108 if (ret) {
2109 btrfs_remove_free_space_cache(bg);
2110 btrfs_put_block_group(bg);
2111 break;
2112 }
2113 btrfs_update_space_info(fs_info, bg->flags, em->len, em->len,
2114 0, 0, &space_info);
2115 bg->space_info = space_info;
2116 link_block_group(bg);
2117
2118 set_avail_alloc_bits(fs_info, bg->flags);
2119 }
2120 if (!ret)
2121 btrfs_init_global_block_rsv(fs_info);
2122 return ret;
2123}
2124
2125int btrfs_read_block_groups(struct btrfs_fs_info *info)
2126{
2127 struct btrfs_path *path;
2128 int ret;
2129 struct btrfs_block_group *cache;
2130 struct btrfs_space_info *space_info;
2131 struct btrfs_key key;
2132 int need_clear = 0;
2133 u64 cache_gen;
2134
2135 if (!info->extent_root)
2136 return fill_dummy_bgs(info);
2137
2138 key.objectid = 0;
2139 key.offset = 0;
2140 key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
2141 path = btrfs_alloc_path();
2142 if (!path)
2143 return -ENOMEM;
2144
2145 cache_gen = btrfs_super_cache_generation(info->super_copy);
2146 if (btrfs_test_opt(info, SPACE_CACHE) &&
2147 btrfs_super_generation(info->super_copy) != cache_gen)
2148 need_clear = 1;
2149 if (btrfs_test_opt(info, CLEAR_CACHE))
2150 need_clear = 1;
2151
2152 while (1) {
2153 struct btrfs_block_group_item bgi;
2154 struct extent_buffer *leaf;
2155 int slot;
2156
2157 ret = find_first_block_group(info, path, &key);
2158 if (ret > 0)
2159 break;
2160 if (ret != 0)
2161 goto error;
2162
2163 leaf = path->nodes[0];
2164 slot = path->slots[0];
2165
2166 read_extent_buffer(leaf, &bgi, btrfs_item_ptr_offset(leaf, slot),
2167 sizeof(bgi));
2168
2169 btrfs_item_key_to_cpu(leaf, &key, slot);
2170 btrfs_release_path(path);
2171 ret = read_one_block_group(info, &bgi, &key, need_clear);
2172 if (ret < 0)
2173 goto error;
2174 key.objectid += key.offset;
2175 key.offset = 0;
2176 }
2177 btrfs_release_path(path);
2178
2179 list_for_each_entry(space_info, &info->space_info, list) {
2180 int i;
2181
2182 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2183 if (list_empty(&space_info->block_groups[i]))
2184 continue;
2185 cache = list_first_entry(&space_info->block_groups[i],
2186 struct btrfs_block_group,
2187 list);
2188 btrfs_sysfs_add_block_group_type(cache);
2189 }
2190
2191 if (!(btrfs_get_alloc_profile(info, space_info->flags) &
2192 (BTRFS_BLOCK_GROUP_RAID10 |
2193 BTRFS_BLOCK_GROUP_RAID1_MASK |
2194 BTRFS_BLOCK_GROUP_RAID56_MASK |
2195 BTRFS_BLOCK_GROUP_DUP)))
2196 continue;
2197 /*
2198 * Avoid allocating from un-mirrored block group if there are
2199 * mirrored block groups.
2200 */
2201 list_for_each_entry(cache,
2202 &space_info->block_groups[BTRFS_RAID_RAID0],
2203 list)
2204 inc_block_group_ro(cache, 1);
2205 list_for_each_entry(cache,
2206 &space_info->block_groups[BTRFS_RAID_SINGLE],
2207 list)
2208 inc_block_group_ro(cache, 1);
2209 }
2210
2211 btrfs_init_global_block_rsv(info);
2212 ret = check_chunk_block_group_mappings(info);
2213error:
2214 btrfs_free_path(path);
2215 return ret;
2216}
2217
2218/*
2219 * This function, insert_block_group_item(), belongs to the phase 2 of chunk
2220 * allocation.
2221 *
2222 * See the comment at btrfs_chunk_alloc() for details about the chunk allocation
2223 * phases.
2224 */
2225static int insert_block_group_item(struct btrfs_trans_handle *trans,
2226 struct btrfs_block_group *block_group)
2227{
2228 struct btrfs_fs_info *fs_info = trans->fs_info;
2229 struct btrfs_block_group_item bgi;
2230 struct btrfs_root *root;
2231 struct btrfs_key key;
2232
2233 spin_lock(&block_group->lock);
2234 btrfs_set_stack_block_group_used(&bgi, block_group->used);
2235 btrfs_set_stack_block_group_chunk_objectid(&bgi,
2236 BTRFS_FIRST_CHUNK_TREE_OBJECTID);
2237 btrfs_set_stack_block_group_flags(&bgi, block_group->flags);
2238 key.objectid = block_group->start;
2239 key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
2240 key.offset = block_group->length;
2241 spin_unlock(&block_group->lock);
2242
2243 root = fs_info->extent_root;
2244 return btrfs_insert_item(trans, root, &key, &bgi, sizeof(bgi));
2245}
2246
2247/*
2248 * This function, btrfs_create_pending_block_groups(), belongs to the phase 2 of
2249 * chunk allocation.
2250 *
2251 * See the comment at btrfs_chunk_alloc() for details about the chunk allocation
2252 * phases.
2253 */
2254void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans)
2255{
2256 struct btrfs_fs_info *fs_info = trans->fs_info;
2257 struct btrfs_block_group *block_group;
2258 int ret = 0;
2259
2260 while (!list_empty(&trans->new_bgs)) {
2261 int index;
2262
2263 block_group = list_first_entry(&trans->new_bgs,
2264 struct btrfs_block_group,
2265 bg_list);
2266 if (ret)
2267 goto next;
2268
2269 index = btrfs_bg_flags_to_raid_index(block_group->flags);
2270
2271 ret = insert_block_group_item(trans, block_group);
2272 if (ret)
2273 btrfs_abort_transaction(trans, ret);
2274 if (!block_group->chunk_item_inserted) {
2275 mutex_lock(&fs_info->chunk_mutex);
2276 ret = btrfs_chunk_alloc_add_chunk_item(trans, block_group);
2277 mutex_unlock(&fs_info->chunk_mutex);
2278 if (ret)
2279 btrfs_abort_transaction(trans, ret);
2280 }
2281 ret = btrfs_finish_chunk_alloc(trans, block_group->start,
2282 block_group->length);
2283 if (ret)
2284 btrfs_abort_transaction(trans, ret);
2285 add_block_group_free_space(trans, block_group);
2286
2287 /*
2288 * If we restriped during balance, we may have added a new raid
2289 * type, so now add the sysfs entries when it is safe to do so.
2290 * We don't have to worry about locking here as it's handled in
2291 * btrfs_sysfs_add_block_group_type.
2292 */
2293 if (block_group->space_info->block_group_kobjs[index] == NULL)
2294 btrfs_sysfs_add_block_group_type(block_group);
2295
2296 /* Already aborted the transaction if it failed. */
2297next:
2298 btrfs_delayed_refs_rsv_release(fs_info, 1);
2299 list_del_init(&block_group->bg_list);
2300 }
2301 btrfs_trans_release_chunk_metadata(trans);
2302}
2303
2304struct btrfs_block_group *btrfs_make_block_group(struct btrfs_trans_handle *trans,
2305 u64 bytes_used, u64 type,
2306 u64 chunk_offset, u64 size)
2307{
2308 struct btrfs_fs_info *fs_info = trans->fs_info;
2309 struct btrfs_block_group *cache;
2310 int ret;
2311
2312 btrfs_set_log_full_commit(trans);
2313
2314 cache = btrfs_create_block_group_cache(fs_info, chunk_offset);
2315 if (!cache)
2316 return ERR_PTR(-ENOMEM);
2317
2318 cache->length = size;
2319 set_free_space_tree_thresholds(cache);
2320 cache->used = bytes_used;
2321 cache->flags = type;
2322 cache->last_byte_to_unpin = (u64)-1;
2323 cache->cached = BTRFS_CACHE_FINISHED;
2324 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
2325 cache->needs_free_space = 1;
2326
2327 ret = btrfs_load_block_group_zone_info(cache, true);
2328 if (ret) {
2329 btrfs_put_block_group(cache);
2330 return ERR_PTR(ret);
2331 }
2332
2333 ret = exclude_super_stripes(cache);
2334 if (ret) {
2335 /* We may have excluded something, so call this just in case */
2336 btrfs_free_excluded_extents(cache);
2337 btrfs_put_block_group(cache);
2338 return ERR_PTR(ret);
2339 }
2340
2341 add_new_free_space(cache, chunk_offset, chunk_offset + size);
2342
2343 btrfs_free_excluded_extents(cache);
2344
2345#ifdef CONFIG_BTRFS_DEBUG
2346 if (btrfs_should_fragment_free_space(cache)) {
2347 u64 new_bytes_used = size - bytes_used;
2348
2349 bytes_used += new_bytes_used >> 1;
2350 fragment_free_space(cache);
2351 }
2352#endif
2353 /*
2354 * Ensure the corresponding space_info object is created and
2355 * assigned to our block group. We want our bg to be added to the rbtree
2356 * with its ->space_info set.
2357 */
2358 cache->space_info = btrfs_find_space_info(fs_info, cache->flags);
2359 ASSERT(cache->space_info);
2360
2361 ret = btrfs_add_block_group_cache(fs_info, cache);
2362 if (ret) {
2363 btrfs_remove_free_space_cache(cache);
2364 btrfs_put_block_group(cache);
2365 return ERR_PTR(ret);
2366 }
2367
2368 /*
2369 * Now that our block group has its ->space_info set and is inserted in
2370 * the rbtree, update the space info's counters.
2371 */
2372 trace_btrfs_add_block_group(fs_info, cache, 1);
2373 btrfs_update_space_info(fs_info, cache->flags, size, bytes_used,
2374 cache->bytes_super, 0, &cache->space_info);
2375 btrfs_update_global_block_rsv(fs_info);
2376
2377 link_block_group(cache);
2378
2379 list_add_tail(&cache->bg_list, &trans->new_bgs);
2380 trans->delayed_ref_updates++;
2381 btrfs_update_delayed_refs_rsv(trans);
2382
2383 set_avail_alloc_bits(fs_info, type);
2384 return cache;
2385}
2386
2387/*
2388 * Mark one block group RO, can be called several times for the same block
2389 * group.
2390 *
2391 * @cache: the destination block group
2392 * @do_chunk_alloc: whether need to do chunk pre-allocation, this is to
2393 * ensure we still have some free space after marking this
2394 * block group RO.
2395 */
2396int btrfs_inc_block_group_ro(struct btrfs_block_group *cache,
2397 bool do_chunk_alloc)
2398{
2399 struct btrfs_fs_info *fs_info = cache->fs_info;
2400 struct btrfs_trans_handle *trans;
2401 u64 alloc_flags;
2402 int ret;
2403 bool dirty_bg_running;
2404
2405 do {
2406 trans = btrfs_join_transaction(fs_info->extent_root);
2407 if (IS_ERR(trans))
2408 return PTR_ERR(trans);
2409
2410 dirty_bg_running = false;
2411
2412 /*
2413 * We're not allowed to set block groups readonly after the dirty
2414 * block group cache has started writing. If it already started,
2415 * back off and let this transaction commit.
2416 */
2417 mutex_lock(&fs_info->ro_block_group_mutex);
2418 if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
2419 u64 transid = trans->transid;
2420
2421 mutex_unlock(&fs_info->ro_block_group_mutex);
2422 btrfs_end_transaction(trans);
2423
2424 ret = btrfs_wait_for_commit(fs_info, transid);
2425 if (ret)
2426 return ret;
2427 dirty_bg_running = true;
2428 }
2429 } while (dirty_bg_running);
2430
2431 if (do_chunk_alloc) {
2432 /*
2433 * If we are changing raid levels, try to allocate a
2434 * corresponding block group with the new raid level.
2435 */
2436 alloc_flags = btrfs_get_alloc_profile(fs_info, cache->flags);
2437 if (alloc_flags != cache->flags) {
2438 ret = btrfs_chunk_alloc(trans, alloc_flags,
2439 CHUNK_ALLOC_FORCE);
2440 /*
2441 * ENOSPC is allowed here, we may have enough space
2442 * already allocated at the new raid level to carry on
2443 */
2444 if (ret == -ENOSPC)
2445 ret = 0;
2446 if (ret < 0)
2447 goto out;
2448 }
2449 }
2450
2451 ret = inc_block_group_ro(cache, 0);
2452 if (!do_chunk_alloc || ret == -ETXTBSY)
2453 goto unlock_out;
2454 if (!ret)
2455 goto out;
2456 alloc_flags = btrfs_get_alloc_profile(fs_info, cache->space_info->flags);
2457 ret = btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
2458 if (ret < 0)
2459 goto out;
2460 ret = inc_block_group_ro(cache, 0);
2461 if (ret == -ETXTBSY)
2462 goto unlock_out;
2463out:
2464 if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
2465 alloc_flags = btrfs_get_alloc_profile(fs_info, cache->flags);
2466 mutex_lock(&fs_info->chunk_mutex);
2467 check_system_chunk(trans, alloc_flags);
2468 mutex_unlock(&fs_info->chunk_mutex);
2469 }
2470unlock_out:
2471 mutex_unlock(&fs_info->ro_block_group_mutex);
2472
2473 btrfs_end_transaction(trans);
2474 return ret;
2475}
2476
2477void btrfs_dec_block_group_ro(struct btrfs_block_group *cache)
2478{
2479 struct btrfs_space_info *sinfo = cache->space_info;
2480 u64 num_bytes;
2481
2482 BUG_ON(!cache->ro);
2483
2484 spin_lock(&sinfo->lock);
2485 spin_lock(&cache->lock);
2486 if (!--cache->ro) {
2487 if (btrfs_is_zoned(cache->fs_info)) {
2488 /* Migrate zone_unusable bytes back */
2489 cache->zone_unusable = cache->alloc_offset - cache->used;
2490 sinfo->bytes_zone_unusable += cache->zone_unusable;
2491 sinfo->bytes_readonly -= cache->zone_unusable;
2492 }
2493 num_bytes = cache->length - cache->reserved -
2494 cache->pinned - cache->bytes_super -
2495 cache->zone_unusable - cache->used;
2496 sinfo->bytes_readonly -= num_bytes;
2497 list_del_init(&cache->ro_list);
2498 }
2499 spin_unlock(&cache->lock);
2500 spin_unlock(&sinfo->lock);
2501}
2502
2503static int update_block_group_item(struct btrfs_trans_handle *trans,
2504 struct btrfs_path *path,
2505 struct btrfs_block_group *cache)
2506{
2507 struct btrfs_fs_info *fs_info = trans->fs_info;
2508 int ret;
2509 struct btrfs_root *root = fs_info->extent_root;
2510 unsigned long bi;
2511 struct extent_buffer *leaf;
2512 struct btrfs_block_group_item bgi;
2513 struct btrfs_key key;
2514
2515 key.objectid = cache->start;
2516 key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
2517 key.offset = cache->length;
2518
2519 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2520 if (ret) {
2521 if (ret > 0)
2522 ret = -ENOENT;
2523 goto fail;
2524 }
2525
2526 leaf = path->nodes[0];
2527 bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
2528 btrfs_set_stack_block_group_used(&bgi, cache->used);
2529 btrfs_set_stack_block_group_chunk_objectid(&bgi,
2530 BTRFS_FIRST_CHUNK_TREE_OBJECTID);
2531 btrfs_set_stack_block_group_flags(&bgi, cache->flags);
2532 write_extent_buffer(leaf, &bgi, bi, sizeof(bgi));
2533 btrfs_mark_buffer_dirty(leaf);
2534fail:
2535 btrfs_release_path(path);
2536 return ret;
2537
2538}
2539
2540static int cache_save_setup(struct btrfs_block_group *block_group,
2541 struct btrfs_trans_handle *trans,
2542 struct btrfs_path *path)
2543{
2544 struct btrfs_fs_info *fs_info = block_group->fs_info;
2545 struct btrfs_root *root = fs_info->tree_root;
2546 struct inode *inode = NULL;
2547 struct extent_changeset *data_reserved = NULL;
2548 u64 alloc_hint = 0;
2549 int dcs = BTRFS_DC_ERROR;
2550 u64 cache_size = 0;
2551 int retries = 0;
2552 int ret = 0;
2553
2554 if (!btrfs_test_opt(fs_info, SPACE_CACHE))
2555 return 0;
2556
2557 /*
2558 * If this block group is smaller than 100 megs don't bother caching the
2559 * block group.
2560 */
2561 if (block_group->length < (100 * SZ_1M)) {
2562 spin_lock(&block_group->lock);
2563 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
2564 spin_unlock(&block_group->lock);
2565 return 0;
2566 }
2567
2568 if (TRANS_ABORTED(trans))
2569 return 0;
2570again:
2571 inode = lookup_free_space_inode(block_group, path);
2572 if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
2573 ret = PTR_ERR(inode);
2574 btrfs_release_path(path);
2575 goto out;
2576 }
2577
2578 if (IS_ERR(inode)) {
2579 BUG_ON(retries);
2580 retries++;
2581
2582 if (block_group->ro)
2583 goto out_free;
2584
2585 ret = create_free_space_inode(trans, block_group, path);
2586 if (ret)
2587 goto out_free;
2588 goto again;
2589 }
2590
2591 /*
2592 * We want to set the generation to 0, that way if anything goes wrong
2593 * from here on out we know not to trust this cache when we load up next
2594 * time.
2595 */
2596 BTRFS_I(inode)->generation = 0;
2597 ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
2598 if (ret) {
2599 /*
2600 * So theoretically we could recover from this, simply set the
2601 * super cache generation to 0 so we know to invalidate the
2602 * cache, but then we'd have to keep track of the block groups
2603 * that fail this way so we know we _have_ to reset this cache
2604 * before the next commit or risk reading stale cache. So to
2605 * limit our exposure to horrible edge cases lets just abort the
2606 * transaction, this only happens in really bad situations
2607 * anyway.
2608 */
2609 btrfs_abort_transaction(trans, ret);
2610 goto out_put;
2611 }
2612 WARN_ON(ret);
2613
2614 /* We've already setup this transaction, go ahead and exit */
2615 if (block_group->cache_generation == trans->transid &&
2616 i_size_read(inode)) {
2617 dcs = BTRFS_DC_SETUP;
2618 goto out_put;
2619 }
2620
2621 if (i_size_read(inode) > 0) {
2622 ret = btrfs_check_trunc_cache_free_space(fs_info,
2623 &fs_info->global_block_rsv);
2624 if (ret)
2625 goto out_put;
2626
2627 ret = btrfs_truncate_free_space_cache(trans, NULL, inode);
2628 if (ret)
2629 goto out_put;
2630 }
2631
2632 spin_lock(&block_group->lock);
2633 if (block_group->cached != BTRFS_CACHE_FINISHED ||
2634 !btrfs_test_opt(fs_info, SPACE_CACHE)) {
2635 /*
2636 * don't bother trying to write stuff out _if_
2637 * a) we're not cached,
2638 * b) we're with nospace_cache mount option,
2639 * c) we're with v2 space_cache (FREE_SPACE_TREE).
2640 */
2641 dcs = BTRFS_DC_WRITTEN;
2642 spin_unlock(&block_group->lock);
2643 goto out_put;
2644 }
2645 spin_unlock(&block_group->lock);
2646
2647 /*
2648 * We hit an ENOSPC when setting up the cache in this transaction, just
2649 * skip doing the setup, we've already cleared the cache so we're safe.
2650 */
2651 if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
2652 ret = -ENOSPC;
2653 goto out_put;
2654 }
2655
2656 /*
2657 * Try to preallocate enough space based on how big the block group is.
2658 * Keep in mind this has to include any pinned space which could end up
2659 * taking up quite a bit since it's not folded into the other space
2660 * cache.
2661 */
2662 cache_size = div_u64(block_group->length, SZ_256M);
2663 if (!cache_size)
2664 cache_size = 1;
2665
2666 cache_size *= 16;
2667 cache_size *= fs_info->sectorsize;
2668
2669 ret = btrfs_check_data_free_space(BTRFS_I(inode), &data_reserved, 0,
2670 cache_size);
2671 if (ret)
2672 goto out_put;
2673
2674 ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, cache_size,
2675 cache_size, cache_size,
2676 &alloc_hint);
2677 /*
2678 * Our cache requires contiguous chunks so that we don't modify a bunch
2679 * of metadata or split extents when writing the cache out, which means
2680 * we can enospc if we are heavily fragmented in addition to just normal
2681 * out of space conditions. So if we hit this just skip setting up any
2682 * other block groups for this transaction, maybe we'll unpin enough
2683 * space the next time around.
2684 */
2685 if (!ret)
2686 dcs = BTRFS_DC_SETUP;
2687 else if (ret == -ENOSPC)
2688 set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
2689
2690out_put:
2691 iput(inode);
2692out_free:
2693 btrfs_release_path(path);
2694out:
2695 spin_lock(&block_group->lock);
2696 if (!ret && dcs == BTRFS_DC_SETUP)
2697 block_group->cache_generation = trans->transid;
2698 block_group->disk_cache_state = dcs;
2699 spin_unlock(&block_group->lock);
2700
2701 extent_changeset_free(data_reserved);
2702 return ret;
2703}
2704
2705int btrfs_setup_space_cache(struct btrfs_trans_handle *trans)
2706{
2707 struct btrfs_fs_info *fs_info = trans->fs_info;
2708 struct btrfs_block_group *cache, *tmp;
2709 struct btrfs_transaction *cur_trans = trans->transaction;
2710 struct btrfs_path *path;
2711
2712 if (list_empty(&cur_trans->dirty_bgs) ||
2713 !btrfs_test_opt(fs_info, SPACE_CACHE))
2714 return 0;
2715
2716 path = btrfs_alloc_path();
2717 if (!path)
2718 return -ENOMEM;
2719
2720 /* Could add new block groups, use _safe just in case */
2721 list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
2722 dirty_list) {
2723 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
2724 cache_save_setup(cache, trans, path);
2725 }
2726
2727 btrfs_free_path(path);
2728 return 0;
2729}
2730
2731/*
2732 * Transaction commit does final block group cache writeback during a critical
2733 * section where nothing is allowed to change the FS. This is required in
2734 * order for the cache to actually match the block group, but can introduce a
2735 * lot of latency into the commit.
2736 *
2737 * So, btrfs_start_dirty_block_groups is here to kick off block group cache IO.
2738 * There's a chance we'll have to redo some of it if the block group changes
2739 * again during the commit, but it greatly reduces the commit latency by
2740 * getting rid of the easy block groups while we're still allowing others to
2741 * join the commit.
2742 */
2743int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans)
2744{
2745 struct btrfs_fs_info *fs_info = trans->fs_info;
2746 struct btrfs_block_group *cache;
2747 struct btrfs_transaction *cur_trans = trans->transaction;
2748 int ret = 0;
2749 int should_put;
2750 struct btrfs_path *path = NULL;
2751 LIST_HEAD(dirty);
2752 struct list_head *io = &cur_trans->io_bgs;
2753 int num_started = 0;
2754 int loops = 0;
2755
2756 spin_lock(&cur_trans->dirty_bgs_lock);
2757 if (list_empty(&cur_trans->dirty_bgs)) {
2758 spin_unlock(&cur_trans->dirty_bgs_lock);
2759 return 0;
2760 }
2761 list_splice_init(&cur_trans->dirty_bgs, &dirty);
2762 spin_unlock(&cur_trans->dirty_bgs_lock);
2763
2764again:
2765 /* Make sure all the block groups on our dirty list actually exist */
2766 btrfs_create_pending_block_groups(trans);
2767
2768 if (!path) {
2769 path = btrfs_alloc_path();
2770 if (!path) {
2771 ret = -ENOMEM;
2772 goto out;
2773 }
2774 }
2775
2776 /*
2777 * cache_write_mutex is here only to save us from balance or automatic
2778 * removal of empty block groups deleting this block group while we are
2779 * writing out the cache
2780 */
2781 mutex_lock(&trans->transaction->cache_write_mutex);
2782 while (!list_empty(&dirty)) {
2783 bool drop_reserve = true;
2784
2785 cache = list_first_entry(&dirty, struct btrfs_block_group,
2786 dirty_list);
2787 /*
2788 * This can happen if something re-dirties a block group that
2789 * is already under IO. Just wait for it to finish and then do
2790 * it all again
2791 */
2792 if (!list_empty(&cache->io_list)) {
2793 list_del_init(&cache->io_list);
2794 btrfs_wait_cache_io(trans, cache, path);
2795 btrfs_put_block_group(cache);
2796 }
2797
2798
2799 /*
2800 * btrfs_wait_cache_io uses the cache->dirty_list to decide if
2801 * it should update the cache_state. Don't delete until after
2802 * we wait.
2803 *
2804 * Since we're not running in the commit critical section
2805 * we need the dirty_bgs_lock to protect from update_block_group
2806 */
2807 spin_lock(&cur_trans->dirty_bgs_lock);
2808 list_del_init(&cache->dirty_list);
2809 spin_unlock(&cur_trans->dirty_bgs_lock);
2810
2811 should_put = 1;
2812
2813 cache_save_setup(cache, trans, path);
2814
2815 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
2816 cache->io_ctl.inode = NULL;
2817 ret = btrfs_write_out_cache(trans, cache, path);
2818 if (ret == 0 && cache->io_ctl.inode) {
2819 num_started++;
2820 should_put = 0;
2821
2822 /*
2823 * The cache_write_mutex is protecting the
2824 * io_list, also refer to the definition of
2825 * btrfs_transaction::io_bgs for more details
2826 */
2827 list_add_tail(&cache->io_list, io);
2828 } else {
2829 /*
2830 * If we failed to write the cache, the
2831 * generation will be bad and life goes on
2832 */
2833 ret = 0;
2834 }
2835 }
2836 if (!ret) {
2837 ret = update_block_group_item(trans, path, cache);
2838 /*
2839 * Our block group might still be attached to the list
2840 * of new block groups in the transaction handle of some
2841 * other task (struct btrfs_trans_handle->new_bgs). This
2842 * means its block group item isn't yet in the extent
2843 * tree. If this happens ignore the error, as we will
2844 * try again later in the critical section of the
2845 * transaction commit.
2846 */
2847 if (ret == -ENOENT) {
2848 ret = 0;
2849 spin_lock(&cur_trans->dirty_bgs_lock);
2850 if (list_empty(&cache->dirty_list)) {
2851 list_add_tail(&cache->dirty_list,
2852 &cur_trans->dirty_bgs);
2853 btrfs_get_block_group(cache);
2854 drop_reserve = false;
2855 }
2856 spin_unlock(&cur_trans->dirty_bgs_lock);
2857 } else if (ret) {
2858 btrfs_abort_transaction(trans, ret);
2859 }
2860 }
2861
2862 /* If it's not on the io list, we need to put the block group */
2863 if (should_put)
2864 btrfs_put_block_group(cache);
2865 if (drop_reserve)
2866 btrfs_delayed_refs_rsv_release(fs_info, 1);
2867 /*
2868 * Avoid blocking other tasks for too long. It might even save
2869 * us from writing caches for block groups that are going to be
2870 * removed.
2871 */
2872 mutex_unlock(&trans->transaction->cache_write_mutex);
2873 if (ret)
2874 goto out;
2875 mutex_lock(&trans->transaction->cache_write_mutex);
2876 }
2877 mutex_unlock(&trans->transaction->cache_write_mutex);
2878
2879 /*
2880 * Go through delayed refs for all the stuff we've just kicked off
2881 * and then loop back (just once)
2882 */
2883 if (!ret)
2884 ret = btrfs_run_delayed_refs(trans, 0);
2885 if (!ret && loops == 0) {
2886 loops++;
2887 spin_lock(&cur_trans->dirty_bgs_lock);
2888 list_splice_init(&cur_trans->dirty_bgs, &dirty);
2889 /*
2890 * dirty_bgs_lock protects us from concurrent block group
2891 * deletes too (not just cache_write_mutex).
2892 */
2893 if (!list_empty(&dirty)) {
2894 spin_unlock(&cur_trans->dirty_bgs_lock);
2895 goto again;
2896 }
2897 spin_unlock(&cur_trans->dirty_bgs_lock);
2898 }
2899out:
2900 if (ret < 0) {
2901 spin_lock(&cur_trans->dirty_bgs_lock);
2902 list_splice_init(&dirty, &cur_trans->dirty_bgs);
2903 spin_unlock(&cur_trans->dirty_bgs_lock);
2904 btrfs_cleanup_dirty_bgs(cur_trans, fs_info);
2905 }
2906
2907 btrfs_free_path(path);
2908 return ret;
2909}
2910
2911int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans)
2912{
2913 struct btrfs_fs_info *fs_info = trans->fs_info;
2914 struct btrfs_block_group *cache;
2915 struct btrfs_transaction *cur_trans = trans->transaction;
2916 int ret = 0;
2917 int should_put;
2918 struct btrfs_path *path;
2919 struct list_head *io = &cur_trans->io_bgs;
2920 int num_started = 0;
2921
2922 path = btrfs_alloc_path();
2923 if (!path)
2924 return -ENOMEM;
2925
2926 /*
2927 * Even though we are in the critical section of the transaction commit,
2928 * we can still have concurrent tasks adding elements to this
2929 * transaction's list of dirty block groups. These tasks correspond to
2930 * endio free space workers started when writeback finishes for a
2931 * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
2932 * allocate new block groups as a result of COWing nodes of the root
2933 * tree when updating the free space inode. The writeback for the space
2934 * caches is triggered by an earlier call to
2935 * btrfs_start_dirty_block_groups() and iterations of the following
2936 * loop.
2937 * Also we want to do the cache_save_setup first and then run the
2938 * delayed refs to make sure we have the best chance at doing this all
2939 * in one shot.
2940 */
2941 spin_lock(&cur_trans->dirty_bgs_lock);
2942 while (!list_empty(&cur_trans->dirty_bgs)) {
2943 cache = list_first_entry(&cur_trans->dirty_bgs,
2944 struct btrfs_block_group,
2945 dirty_list);
2946
2947 /*
2948 * This can happen if cache_save_setup re-dirties a block group
2949 * that is already under IO. Just wait for it to finish and
2950 * then do it all again
2951 */
2952 if (!list_empty(&cache->io_list)) {
2953 spin_unlock(&cur_trans->dirty_bgs_lock);
2954 list_del_init(&cache->io_list);
2955 btrfs_wait_cache_io(trans, cache, path);
2956 btrfs_put_block_group(cache);
2957 spin_lock(&cur_trans->dirty_bgs_lock);
2958 }
2959
2960 /*
2961 * Don't remove from the dirty list until after we've waited on
2962 * any pending IO
2963 */
2964 list_del_init(&cache->dirty_list);
2965 spin_unlock(&cur_trans->dirty_bgs_lock);
2966 should_put = 1;
2967
2968 cache_save_setup(cache, trans, path);
2969
2970 if (!ret)
2971 ret = btrfs_run_delayed_refs(trans,
2972 (unsigned long) -1);
2973
2974 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
2975 cache->io_ctl.inode = NULL;
2976 ret = btrfs_write_out_cache(trans, cache, path);
2977 if (ret == 0 && cache->io_ctl.inode) {
2978 num_started++;
2979 should_put = 0;
2980 list_add_tail(&cache->io_list, io);
2981 } else {
2982 /*
2983 * If we failed to write the cache, the
2984 * generation will be bad and life goes on
2985 */
2986 ret = 0;
2987 }
2988 }
2989 if (!ret) {
2990 ret = update_block_group_item(trans, path, cache);
2991 /*
2992 * One of the free space endio workers might have
2993 * created a new block group while updating a free space
2994 * cache's inode (at inode.c:btrfs_finish_ordered_io())
2995 * and hasn't released its transaction handle yet, in
2996 * which case the new block group is still attached to
2997 * its transaction handle and its creation has not
2998 * finished yet (no block group item in the extent tree
2999 * yet, etc). If this is the case, wait for all free
3000 * space endio workers to finish and retry. This is a
3001 * very rare case so no need for a more efficient and
3002 * complex approach.
3003 */
3004 if (ret == -ENOENT) {
3005 wait_event(cur_trans->writer_wait,
3006 atomic_read(&cur_trans->num_writers) == 1);
3007 ret = update_block_group_item(trans, path, cache);
3008 }
3009 if (ret)
3010 btrfs_abort_transaction(trans, ret);
3011 }
3012
3013 /* If its not on the io list, we need to put the block group */
3014 if (should_put)
3015 btrfs_put_block_group(cache);
3016 btrfs_delayed_refs_rsv_release(fs_info, 1);
3017 spin_lock(&cur_trans->dirty_bgs_lock);
3018 }
3019 spin_unlock(&cur_trans->dirty_bgs_lock);
3020
3021 /*
3022 * Refer to the definition of io_bgs member for details why it's safe
3023 * to use it without any locking
3024 */
3025 while (!list_empty(io)) {
3026 cache = list_first_entry(io, struct btrfs_block_group,
3027 io_list);
3028 list_del_init(&cache->io_list);
3029 btrfs_wait_cache_io(trans, cache, path);
3030 btrfs_put_block_group(cache);
3031 }
3032
3033 btrfs_free_path(path);
3034 return ret;
3035}
3036
3037int btrfs_update_block_group(struct btrfs_trans_handle *trans,
3038 u64 bytenr, u64 num_bytes, int alloc)
3039{
3040 struct btrfs_fs_info *info = trans->fs_info;
3041 struct btrfs_block_group *cache = NULL;
3042 u64 total = num_bytes;
3043 u64 old_val;
3044 u64 byte_in_group;
3045 int factor;
3046 int ret = 0;
3047
3048 /* Block accounting for super block */
3049 spin_lock(&info->delalloc_root_lock);
3050 old_val = btrfs_super_bytes_used(info->super_copy);
3051 if (alloc)
3052 old_val += num_bytes;
3053 else
3054 old_val -= num_bytes;
3055 btrfs_set_super_bytes_used(info->super_copy, old_val);
3056 spin_unlock(&info->delalloc_root_lock);
3057
3058 while (total) {
3059 cache = btrfs_lookup_block_group(info, bytenr);
3060 if (!cache) {
3061 ret = -ENOENT;
3062 break;
3063 }
3064 factor = btrfs_bg_type_to_factor(cache->flags);
3065
3066 /*
3067 * If this block group has free space cache written out, we
3068 * need to make sure to load it if we are removing space. This
3069 * is because we need the unpinning stage to actually add the
3070 * space back to the block group, otherwise we will leak space.
3071 */
3072 if (!alloc && !btrfs_block_group_done(cache))
3073 btrfs_cache_block_group(cache, 1);
3074
3075 byte_in_group = bytenr - cache->start;
3076 WARN_ON(byte_in_group > cache->length);
3077
3078 spin_lock(&cache->space_info->lock);
3079 spin_lock(&cache->lock);
3080
3081 if (btrfs_test_opt(info, SPACE_CACHE) &&
3082 cache->disk_cache_state < BTRFS_DC_CLEAR)
3083 cache->disk_cache_state = BTRFS_DC_CLEAR;
3084
3085 old_val = cache->used;
3086 num_bytes = min(total, cache->length - byte_in_group);
3087 if (alloc) {
3088 old_val += num_bytes;
3089 cache->used = old_val;
3090 cache->reserved -= num_bytes;
3091 cache->space_info->bytes_reserved -= num_bytes;
3092 cache->space_info->bytes_used += num_bytes;
3093 cache->space_info->disk_used += num_bytes * factor;
3094 spin_unlock(&cache->lock);
3095 spin_unlock(&cache->space_info->lock);
3096 } else {
3097 old_val -= num_bytes;
3098 cache->used = old_val;
3099 cache->pinned += num_bytes;
3100 btrfs_space_info_update_bytes_pinned(info,
3101 cache->space_info, num_bytes);
3102 cache->space_info->bytes_used -= num_bytes;
3103 cache->space_info->disk_used -= num_bytes * factor;
3104 spin_unlock(&cache->lock);
3105 spin_unlock(&cache->space_info->lock);
3106
3107 set_extent_dirty(&trans->transaction->pinned_extents,
3108 bytenr, bytenr + num_bytes - 1,
3109 GFP_NOFS | __GFP_NOFAIL);
3110 }
3111
3112 spin_lock(&trans->transaction->dirty_bgs_lock);
3113 if (list_empty(&cache->dirty_list)) {
3114 list_add_tail(&cache->dirty_list,
3115 &trans->transaction->dirty_bgs);
3116 trans->delayed_ref_updates++;
3117 btrfs_get_block_group(cache);
3118 }
3119 spin_unlock(&trans->transaction->dirty_bgs_lock);
3120
3121 /*
3122 * No longer have used bytes in this block group, queue it for
3123 * deletion. We do this after adding the block group to the
3124 * dirty list to avoid races between cleaner kthread and space
3125 * cache writeout.
3126 */
3127 if (!alloc && old_val == 0) {
3128 if (!btrfs_test_opt(info, DISCARD_ASYNC))
3129 btrfs_mark_bg_unused(cache);
3130 }
3131
3132 btrfs_put_block_group(cache);
3133 total -= num_bytes;
3134 bytenr += num_bytes;
3135 }
3136
3137 /* Modified block groups are accounted for in the delayed_refs_rsv. */
3138 btrfs_update_delayed_refs_rsv(trans);
3139 return ret;
3140}
3141
3142/**
3143 * btrfs_add_reserved_bytes - update the block_group and space info counters
3144 * @cache: The cache we are manipulating
3145 * @ram_bytes: The number of bytes of file content, and will be same to
3146 * @num_bytes except for the compress path.
3147 * @num_bytes: The number of bytes in question
3148 * @delalloc: The blocks are allocated for the delalloc write
3149 *
3150 * This is called by the allocator when it reserves space. If this is a
3151 * reservation and the block group has become read only we cannot make the
3152 * reservation and return -EAGAIN, otherwise this function always succeeds.
3153 */
3154int btrfs_add_reserved_bytes(struct btrfs_block_group *cache,
3155 u64 ram_bytes, u64 num_bytes, int delalloc)
3156{
3157 struct btrfs_space_info *space_info = cache->space_info;
3158 int ret = 0;
3159
3160 spin_lock(&space_info->lock);
3161 spin_lock(&cache->lock);
3162 if (cache->ro) {
3163 ret = -EAGAIN;
3164 } else {
3165 cache->reserved += num_bytes;
3166 space_info->bytes_reserved += num_bytes;
3167 trace_btrfs_space_reservation(cache->fs_info, "space_info",
3168 space_info->flags, num_bytes, 1);
3169 btrfs_space_info_update_bytes_may_use(cache->fs_info,
3170 space_info, -ram_bytes);
3171 if (delalloc)
3172 cache->delalloc_bytes += num_bytes;
3173
3174 /*
3175 * Compression can use less space than we reserved, so wake
3176 * tickets if that happens
3177 */
3178 if (num_bytes < ram_bytes)
3179 btrfs_try_granting_tickets(cache->fs_info, space_info);
3180 }
3181 spin_unlock(&cache->lock);
3182 spin_unlock(&space_info->lock);
3183 return ret;
3184}
3185
3186/**
3187 * btrfs_free_reserved_bytes - update the block_group and space info counters
3188 * @cache: The cache we are manipulating
3189 * @num_bytes: The number of bytes in question
3190 * @delalloc: The blocks are allocated for the delalloc write
3191 *
3192 * This is called by somebody who is freeing space that was never actually used
3193 * on disk. For example if you reserve some space for a new leaf in transaction
3194 * A and before transaction A commits you free that leaf, you call this with
3195 * reserve set to 0 in order to clear the reservation.
3196 */
3197void btrfs_free_reserved_bytes(struct btrfs_block_group *cache,
3198 u64 num_bytes, int delalloc)
3199{
3200 struct btrfs_space_info *space_info = cache->space_info;
3201
3202 spin_lock(&space_info->lock);
3203 spin_lock(&cache->lock);
3204 if (cache->ro)
3205 space_info->bytes_readonly += num_bytes;
3206 cache->reserved -= num_bytes;
3207 space_info->bytes_reserved -= num_bytes;
3208 space_info->max_extent_size = 0;
3209
3210 if (delalloc)
3211 cache->delalloc_bytes -= num_bytes;
3212 spin_unlock(&cache->lock);
3213
3214 btrfs_try_granting_tickets(cache->fs_info, space_info);
3215 spin_unlock(&space_info->lock);
3216}
3217
3218static void force_metadata_allocation(struct btrfs_fs_info *info)
3219{
3220 struct list_head *head = &info->space_info;
3221 struct btrfs_space_info *found;
3222
3223 list_for_each_entry(found, head, list) {
3224 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3225 found->force_alloc = CHUNK_ALLOC_FORCE;
3226 }
3227}
3228
3229static int should_alloc_chunk(struct btrfs_fs_info *fs_info,
3230 struct btrfs_space_info *sinfo, int force)
3231{
3232 u64 bytes_used = btrfs_space_info_used(sinfo, false);
3233 u64 thresh;
3234
3235 if (force == CHUNK_ALLOC_FORCE)
3236 return 1;
3237
3238 /*
3239 * in limited mode, we want to have some free space up to
3240 * about 1% of the FS size.
3241 */
3242 if (force == CHUNK_ALLOC_LIMITED) {
3243 thresh = btrfs_super_total_bytes(fs_info->super_copy);
3244 thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
3245
3246 if (sinfo->total_bytes - bytes_used < thresh)
3247 return 1;
3248 }
3249
3250 if (bytes_used + SZ_2M < div_factor(sinfo->total_bytes, 8))
3251 return 0;
3252 return 1;
3253}
3254
3255int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans, u64 type)
3256{
3257 u64 alloc_flags = btrfs_get_alloc_profile(trans->fs_info, type);
3258
3259 return btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
3260}
3261
3262static int do_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags)
3263{
3264 struct btrfs_block_group *bg;
3265 int ret;
3266
3267 /*
3268 * Check if we have enough space in the system space info because we
3269 * will need to update device items in the chunk btree and insert a new
3270 * chunk item in the chunk btree as well. This will allocate a new
3271 * system block group if needed.
3272 */
3273 check_system_chunk(trans, flags);
3274
3275 bg = btrfs_alloc_chunk(trans, flags);
3276 if (IS_ERR(bg)) {
3277 ret = PTR_ERR(bg);
3278 goto out;
3279 }
3280
3281 /*
3282 * If this is a system chunk allocation then stop right here and do not
3283 * add the chunk item to the chunk btree. This is to prevent a deadlock
3284 * because this system chunk allocation can be triggered while COWing
3285 * some extent buffer of the chunk btree and while holding a lock on a
3286 * parent extent buffer, in which case attempting to insert the chunk
3287 * item (or update the device item) would result in a deadlock on that
3288 * parent extent buffer. In this case defer the chunk btree updates to
3289 * the second phase of chunk allocation and keep our reservation until
3290 * the second phase completes.
3291 *
3292 * This is a rare case and can only be triggered by the very few cases
3293 * we have where we need to touch the chunk btree outside chunk allocation
3294 * and chunk removal. These cases are basically adding a device, removing
3295 * a device or resizing a device.
3296 */
3297 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3298 return 0;
3299
3300 ret = btrfs_chunk_alloc_add_chunk_item(trans, bg);
3301 /*
3302 * Normally we are not expected to fail with -ENOSPC here, since we have
3303 * previously reserved space in the system space_info and allocated one
3304 * new system chunk if necessary. However there are two exceptions:
3305 *
3306 * 1) We may have enough free space in the system space_info but all the
3307 * existing system block groups have a profile which can not be used
3308 * for extent allocation.
3309 *
3310 * This happens when mounting in degraded mode. For example we have a
3311 * RAID1 filesystem with 2 devices, lose one device and mount the fs
3312 * using the other device in degraded mode. If we then allocate a chunk,
3313 * we may have enough free space in the existing system space_info, but
3314 * none of the block groups can be used for extent allocation since they
3315 * have a RAID1 profile, and because we are in degraded mode with a
3316 * single device, we are forced to allocate a new system chunk with a
3317 * SINGLE profile. Making check_system_chunk() iterate over all system
3318 * block groups and check if they have a usable profile and enough space
3319 * can be slow on very large filesystems, so we tolerate the -ENOSPC and
3320 * try again after forcing allocation of a new system chunk. Like this
3321 * we avoid paying the cost of that search in normal circumstances, when
3322 * we were not mounted in degraded mode;
3323 *
3324 * 2) We had enough free space info the system space_info, and one suitable
3325 * block group to allocate from when we called check_system_chunk()
3326 * above. However right after we called it, the only system block group
3327 * with enough free space got turned into RO mode by a running scrub,
3328 * and in this case we have to allocate a new one and retry. We only
3329 * need do this allocate and retry once, since we have a transaction
3330 * handle and scrub uses the commit root to search for block groups.
3331 */
3332 if (ret == -ENOSPC) {
3333 const u64 sys_flags = btrfs_system_alloc_profile(trans->fs_info);
3334 struct btrfs_block_group *sys_bg;
3335
3336 sys_bg = btrfs_alloc_chunk(trans, sys_flags);
3337 if (IS_ERR(sys_bg)) {
3338 ret = PTR_ERR(sys_bg);
3339 btrfs_abort_transaction(trans, ret);
3340 goto out;
3341 }
3342
3343 ret = btrfs_chunk_alloc_add_chunk_item(trans, sys_bg);
3344 if (ret) {
3345 btrfs_abort_transaction(trans, ret);
3346 goto out;
3347 }
3348
3349 ret = btrfs_chunk_alloc_add_chunk_item(trans, bg);
3350 if (ret) {
3351 btrfs_abort_transaction(trans, ret);
3352 goto out;
3353 }
3354 } else if (ret) {
3355 btrfs_abort_transaction(trans, ret);
3356 goto out;
3357 }
3358out:
3359 btrfs_trans_release_chunk_metadata(trans);
3360
3361 return ret;
3362}
3363
3364/*
3365 * Chunk allocation is done in 2 phases:
3366 *
3367 * 1) Phase 1 - through btrfs_chunk_alloc() we allocate device extents for
3368 * the chunk, the chunk mapping, create its block group and add the items
3369 * that belong in the chunk btree to it - more specifically, we need to
3370 * update device items in the chunk btree and add a new chunk item to it.
3371 *
3372 * 2) Phase 2 - through btrfs_create_pending_block_groups(), we add the block
3373 * group item to the extent btree and the device extent items to the devices
3374 * btree.
3375 *
3376 * This is done to prevent deadlocks. For example when COWing a node from the
3377 * extent btree we are holding a write lock on the node's parent and if we
3378 * trigger chunk allocation and attempted to insert the new block group item
3379 * in the extent btree right way, we could deadlock because the path for the
3380 * insertion can include that parent node. At first glance it seems impossible
3381 * to trigger chunk allocation after starting a transaction since tasks should
3382 * reserve enough transaction units (metadata space), however while that is true
3383 * most of the time, chunk allocation may still be triggered for several reasons:
3384 *
3385 * 1) When reserving metadata, we check if there is enough free space in the
3386 * metadata space_info and therefore don't trigger allocation of a new chunk.
3387 * However later when the task actually tries to COW an extent buffer from
3388 * the extent btree or from the device btree for example, it is forced to
3389 * allocate a new block group (chunk) because the only one that had enough
3390 * free space was just turned to RO mode by a running scrub for example (or
3391 * device replace, block group reclaim thread, etc), so we can not use it
3392 * for allocating an extent and end up being forced to allocate a new one;
3393 *
3394 * 2) Because we only check that the metadata space_info has enough free bytes,
3395 * we end up not allocating a new metadata chunk in that case. However if
3396 * the filesystem was mounted in degraded mode, none of the existing block
3397 * groups might be suitable for extent allocation due to their incompatible
3398 * profile (for e.g. mounting a 2 devices filesystem, where all block groups
3399 * use a RAID1 profile, in degraded mode using a single device). In this case
3400 * when the task attempts to COW some extent buffer of the extent btree for
3401 * example, it will trigger allocation of a new metadata block group with a
3402 * suitable profile (SINGLE profile in the example of the degraded mount of
3403 * the RAID1 filesystem);
3404 *
3405 * 3) The task has reserved enough transaction units / metadata space, but when
3406 * it attempts to COW an extent buffer from the extent or device btree for
3407 * example, it does not find any free extent in any metadata block group,
3408 * therefore forced to try to allocate a new metadata block group.
3409 * This is because some other task allocated all available extents in the
3410 * meanwhile - this typically happens with tasks that don't reserve space
3411 * properly, either intentionally or as a bug. One example where this is
3412 * done intentionally is fsync, as it does not reserve any transaction units
3413 * and ends up allocating a variable number of metadata extents for log
3414 * tree extent buffers.
3415 *
3416 * We also need this 2 phases setup when adding a device to a filesystem with
3417 * a seed device - we must create new metadata and system chunks without adding
3418 * any of the block group items to the chunk, extent and device btrees. If we
3419 * did not do it this way, we would get ENOSPC when attempting to update those
3420 * btrees, since all the chunks from the seed device are read-only.
3421 *
3422 * Phase 1 does the updates and insertions to the chunk btree because if we had
3423 * it done in phase 2 and have a thundering herd of tasks allocating chunks in
3424 * parallel, we risk having too many system chunks allocated by many tasks if
3425 * many tasks reach phase 1 without the previous ones completing phase 2. In the
3426 * extreme case this leads to exhaustion of the system chunk array in the
3427 * superblock. This is easier to trigger if using a btree node/leaf size of 64K
3428 * and with RAID filesystems (so we have more device items in the chunk btree).
3429 * This has happened before and commit eafa4fd0ad0607 ("btrfs: fix exhaustion of
3430 * the system chunk array due to concurrent allocations") provides more details.
3431 *
3432 * For allocation of system chunks, we defer the updates and insertions into the
3433 * chunk btree to phase 2. This is to prevent deadlocks on extent buffers because
3434 * if the chunk allocation is triggered while COWing an extent buffer of the
3435 * chunk btree, we are holding a lock on the parent of that extent buffer and
3436 * doing the chunk btree updates and insertions can require locking that parent.
3437 * This is for the very few and rare cases where we update the chunk btree that
3438 * are not chunk allocation or chunk removal: adding a device, removing a device
3439 * or resizing a device.
3440 *
3441 * The reservation of system space, done through check_system_chunk(), as well
3442 * as all the updates and insertions into the chunk btree must be done while
3443 * holding fs_info->chunk_mutex. This is important to guarantee that while COWing
3444 * an extent buffer from the chunks btree we never trigger allocation of a new
3445 * system chunk, which would result in a deadlock (trying to lock twice an
3446 * extent buffer of the chunk btree, first time before triggering the chunk
3447 * allocation and the second time during chunk allocation while attempting to
3448 * update the chunks btree). The system chunk array is also updated while holding
3449 * that mutex. The same logic applies to removing chunks - we must reserve system
3450 * space, update the chunk btree and the system chunk array in the superblock
3451 * while holding fs_info->chunk_mutex.
3452 *
3453 * This function, btrfs_chunk_alloc(), belongs to phase 1.
3454 *
3455 * If @force is CHUNK_ALLOC_FORCE:
3456 * - return 1 if it successfully allocates a chunk,
3457 * - return errors including -ENOSPC otherwise.
3458 * If @force is NOT CHUNK_ALLOC_FORCE:
3459 * - return 0 if it doesn't need to allocate a new chunk,
3460 * - return 1 if it successfully allocates a chunk,
3461 * - return errors including -ENOSPC otherwise.
3462 */
3463int btrfs_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags,
3464 enum btrfs_chunk_alloc_enum force)
3465{
3466 struct btrfs_fs_info *fs_info = trans->fs_info;
3467 struct btrfs_space_info *space_info;
3468 bool wait_for_alloc = false;
3469 bool should_alloc = false;
3470 int ret = 0;
3471
3472 /* Don't re-enter if we're already allocating a chunk */
3473 if (trans->allocating_chunk)
3474 return -ENOSPC;
3475 /*
3476 * If we are removing a chunk, don't re-enter or we would deadlock.
3477 * System space reservation and system chunk allocation is done by the
3478 * chunk remove operation (btrfs_remove_chunk()).
3479 */
3480 if (trans->removing_chunk)
3481 return -ENOSPC;
3482
3483 space_info = btrfs_find_space_info(fs_info, flags);
3484 ASSERT(space_info);
3485
3486 do {
3487 spin_lock(&space_info->lock);
3488 if (force < space_info->force_alloc)
3489 force = space_info->force_alloc;
3490 should_alloc = should_alloc_chunk(fs_info, space_info, force);
3491 if (space_info->full) {
3492 /* No more free physical space */
3493 if (should_alloc)
3494 ret = -ENOSPC;
3495 else
3496 ret = 0;
3497 spin_unlock(&space_info->lock);
3498 return ret;
3499 } else if (!should_alloc) {
3500 spin_unlock(&space_info->lock);
3501 return 0;
3502 } else if (space_info->chunk_alloc) {
3503 /*
3504 * Someone is already allocating, so we need to block
3505 * until this someone is finished and then loop to
3506 * recheck if we should continue with our allocation
3507 * attempt.
3508 */
3509 wait_for_alloc = true;
3510 spin_unlock(&space_info->lock);
3511 mutex_lock(&fs_info->chunk_mutex);
3512 mutex_unlock(&fs_info->chunk_mutex);
3513 } else {
3514 /* Proceed with allocation */
3515 space_info->chunk_alloc = 1;
3516 wait_for_alloc = false;
3517 spin_unlock(&space_info->lock);
3518 }
3519
3520 cond_resched();
3521 } while (wait_for_alloc);
3522
3523 mutex_lock(&fs_info->chunk_mutex);
3524 trans->allocating_chunk = true;
3525
3526 /*
3527 * If we have mixed data/metadata chunks we want to make sure we keep
3528 * allocating mixed chunks instead of individual chunks.
3529 */
3530 if (btrfs_mixed_space_info(space_info))
3531 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3532
3533 /*
3534 * if we're doing a data chunk, go ahead and make sure that
3535 * we keep a reasonable number of metadata chunks allocated in the
3536 * FS as well.
3537 */
3538 if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3539 fs_info->data_chunk_allocations++;
3540 if (!(fs_info->data_chunk_allocations %
3541 fs_info->metadata_ratio))
3542 force_metadata_allocation(fs_info);
3543 }
3544
3545 ret = do_chunk_alloc(trans, flags);
3546 trans->allocating_chunk = false;
3547
3548 spin_lock(&space_info->lock);
3549 if (ret < 0) {
3550 if (ret == -ENOSPC)
3551 space_info->full = 1;
3552 else
3553 goto out;
3554 } else {
3555 ret = 1;
3556 space_info->max_extent_size = 0;
3557 }
3558
3559 space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3560out:
3561 space_info->chunk_alloc = 0;
3562 spin_unlock(&space_info->lock);
3563 mutex_unlock(&fs_info->chunk_mutex);
3564
3565 return ret;
3566}
3567
3568static u64 get_profile_num_devs(struct btrfs_fs_info *fs_info, u64 type)
3569{
3570 u64 num_dev;
3571
3572 num_dev = btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)].devs_max;
3573 if (!num_dev)
3574 num_dev = fs_info->fs_devices->rw_devices;
3575
3576 return num_dev;
3577}
3578
3579/*
3580 * Reserve space in the system space for allocating or removing a chunk
3581 */
3582void check_system_chunk(struct btrfs_trans_handle *trans, u64 type)
3583{
3584 struct btrfs_fs_info *fs_info = trans->fs_info;
3585 struct btrfs_space_info *info;
3586 u64 left;
3587 u64 thresh;
3588 int ret = 0;
3589 u64 num_devs;
3590
3591 /*
3592 * Needed because we can end up allocating a system chunk and for an
3593 * atomic and race free space reservation in the chunk block reserve.
3594 */
3595 lockdep_assert_held(&fs_info->chunk_mutex);
3596
3597 info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
3598 spin_lock(&info->lock);
3599 left = info->total_bytes - btrfs_space_info_used(info, true);
3600 spin_unlock(&info->lock);
3601
3602 num_devs = get_profile_num_devs(fs_info, type);
3603
3604 /* num_devs device items to update and 1 chunk item to add or remove */
3605 thresh = btrfs_calc_metadata_size(fs_info, num_devs) +
3606 btrfs_calc_insert_metadata_size(fs_info, 1);
3607
3608 if (left < thresh && btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
3609 btrfs_info(fs_info, "left=%llu, need=%llu, flags=%llu",
3610 left, thresh, type);
3611 btrfs_dump_space_info(fs_info, info, 0, 0);
3612 }
3613
3614 if (left < thresh) {
3615 u64 flags = btrfs_system_alloc_profile(fs_info);
3616 struct btrfs_block_group *bg;
3617
3618 /*
3619 * Ignore failure to create system chunk. We might end up not
3620 * needing it, as we might not need to COW all nodes/leafs from
3621 * the paths we visit in the chunk tree (they were already COWed
3622 * or created in the current transaction for example).
3623 *
3624 * Also, if our caller is allocating a system chunk, do not
3625 * attempt to insert the chunk item in the chunk btree, as we
3626 * could deadlock on an extent buffer since our caller may be
3627 * COWing an extent buffer from the chunk btree.
3628 */
3629 bg = btrfs_alloc_chunk(trans, flags);
3630 if (IS_ERR(bg)) {
3631 ret = PTR_ERR(bg);
3632 } else if (!(type & BTRFS_BLOCK_GROUP_SYSTEM)) {
3633 /*
3634 * If we fail to add the chunk item here, we end up
3635 * trying again at phase 2 of chunk allocation, at
3636 * btrfs_create_pending_block_groups(). So ignore
3637 * any error here.
3638 */
3639 btrfs_chunk_alloc_add_chunk_item(trans, bg);
3640 }
3641 }
3642
3643 if (!ret) {
3644 ret = btrfs_block_rsv_add(fs_info->chunk_root,
3645 &fs_info->chunk_block_rsv,
3646 thresh, BTRFS_RESERVE_NO_FLUSH);
3647 if (!ret)
3648 trans->chunk_bytes_reserved += thresh;
3649 }
3650}
3651
3652void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
3653{
3654 struct btrfs_block_group *block_group;
3655 u64 last = 0;
3656
3657 while (1) {
3658 struct inode *inode;
3659
3660 block_group = btrfs_lookup_first_block_group(info, last);
3661 while (block_group) {
3662 btrfs_wait_block_group_cache_done(block_group);
3663 spin_lock(&block_group->lock);
3664 if (block_group->iref)
3665 break;
3666 spin_unlock(&block_group->lock);
3667 block_group = btrfs_next_block_group(block_group);
3668 }
3669 if (!block_group) {
3670 if (last == 0)
3671 break;
3672 last = 0;
3673 continue;
3674 }
3675
3676 inode = block_group->inode;
3677 block_group->iref = 0;
3678 block_group->inode = NULL;
3679 spin_unlock(&block_group->lock);
3680 ASSERT(block_group->io_ctl.inode == NULL);
3681 iput(inode);
3682 last = block_group->start + block_group->length;
3683 btrfs_put_block_group(block_group);
3684 }
3685}
3686
3687/*
3688 * Must be called only after stopping all workers, since we could have block
3689 * group caching kthreads running, and therefore they could race with us if we
3690 * freed the block groups before stopping them.
3691 */
3692int btrfs_free_block_groups(struct btrfs_fs_info *info)
3693{
3694 struct btrfs_block_group *block_group;
3695 struct btrfs_space_info *space_info;
3696 struct btrfs_caching_control *caching_ctl;
3697 struct rb_node *n;
3698
3699 spin_lock(&info->block_group_cache_lock);
3700 while (!list_empty(&info->caching_block_groups)) {
3701 caching_ctl = list_entry(info->caching_block_groups.next,
3702 struct btrfs_caching_control, list);
3703 list_del(&caching_ctl->list);
3704 btrfs_put_caching_control(caching_ctl);
3705 }
3706 spin_unlock(&info->block_group_cache_lock);
3707
3708 spin_lock(&info->unused_bgs_lock);
3709 while (!list_empty(&info->unused_bgs)) {
3710 block_group = list_first_entry(&info->unused_bgs,
3711 struct btrfs_block_group,
3712 bg_list);
3713 list_del_init(&block_group->bg_list);
3714 btrfs_put_block_group(block_group);
3715 }
3716 spin_unlock(&info->unused_bgs_lock);
3717
3718 spin_lock(&info->unused_bgs_lock);
3719 while (!list_empty(&info->reclaim_bgs)) {
3720 block_group = list_first_entry(&info->reclaim_bgs,
3721 struct btrfs_block_group,
3722 bg_list);
3723 list_del_init(&block_group->bg_list);
3724 btrfs_put_block_group(block_group);
3725 }
3726 spin_unlock(&info->unused_bgs_lock);
3727
3728 spin_lock(&info->block_group_cache_lock);
3729 while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
3730 block_group = rb_entry(n, struct btrfs_block_group,
3731 cache_node);
3732 rb_erase(&block_group->cache_node,
3733 &info->block_group_cache_tree);
3734 RB_CLEAR_NODE(&block_group->cache_node);
3735 spin_unlock(&info->block_group_cache_lock);
3736
3737 down_write(&block_group->space_info->groups_sem);
3738 list_del(&block_group->list);
3739 up_write(&block_group->space_info->groups_sem);
3740
3741 /*
3742 * We haven't cached this block group, which means we could
3743 * possibly have excluded extents on this block group.
3744 */
3745 if (block_group->cached == BTRFS_CACHE_NO ||
3746 block_group->cached == BTRFS_CACHE_ERROR)
3747 btrfs_free_excluded_extents(block_group);
3748
3749 btrfs_remove_free_space_cache(block_group);
3750 ASSERT(block_group->cached != BTRFS_CACHE_STARTED);
3751 ASSERT(list_empty(&block_group->dirty_list));
3752 ASSERT(list_empty(&block_group->io_list));
3753 ASSERT(list_empty(&block_group->bg_list));
3754 ASSERT(refcount_read(&block_group->refs) == 1);
3755 ASSERT(block_group->swap_extents == 0);
3756 btrfs_put_block_group(block_group);
3757
3758 spin_lock(&info->block_group_cache_lock);
3759 }
3760 spin_unlock(&info->block_group_cache_lock);
3761
3762 btrfs_release_global_block_rsv(info);
3763
3764 while (!list_empty(&info->space_info)) {
3765 space_info = list_entry(info->space_info.next,
3766 struct btrfs_space_info,
3767 list);
3768
3769 /*
3770 * Do not hide this behind enospc_debug, this is actually
3771 * important and indicates a real bug if this happens.
3772 */
3773 if (WARN_ON(space_info->bytes_pinned > 0 ||
3774 space_info->bytes_reserved > 0 ||
3775 space_info->bytes_may_use > 0))
3776 btrfs_dump_space_info(info, space_info, 0, 0);
3777 WARN_ON(space_info->reclaim_size > 0);
3778 list_del(&space_info->list);
3779 btrfs_sysfs_remove_space_info(space_info);
3780 }
3781 return 0;
3782}
3783
3784void btrfs_freeze_block_group(struct btrfs_block_group *cache)
3785{
3786 atomic_inc(&cache->frozen);
3787}
3788
3789void btrfs_unfreeze_block_group(struct btrfs_block_group *block_group)
3790{
3791 struct btrfs_fs_info *fs_info = block_group->fs_info;
3792 struct extent_map_tree *em_tree;
3793 struct extent_map *em;
3794 bool cleanup;
3795
3796 spin_lock(&block_group->lock);
3797 cleanup = (atomic_dec_and_test(&block_group->frozen) &&
3798 block_group->removed);
3799 spin_unlock(&block_group->lock);
3800
3801 if (cleanup) {
3802 em_tree = &fs_info->mapping_tree;
3803 write_lock(&em_tree->lock);
3804 em = lookup_extent_mapping(em_tree, block_group->start,
3805 1);
3806 BUG_ON(!em); /* logic error, can't happen */
3807 remove_extent_mapping(em_tree, em);
3808 write_unlock(&em_tree->lock);
3809
3810 /* once for us and once for the tree */
3811 free_extent_map(em);
3812 free_extent_map(em);
3813
3814 /*
3815 * We may have left one free space entry and other possible
3816 * tasks trimming this block group have left 1 entry each one.
3817 * Free them if any.
3818 */
3819 __btrfs_remove_free_space_cache(block_group->free_space_ctl);
3820 }
3821}
3822
3823bool btrfs_inc_block_group_swap_extents(struct btrfs_block_group *bg)
3824{
3825 bool ret = true;
3826
3827 spin_lock(&bg->lock);
3828 if (bg->ro)
3829 ret = false;
3830 else
3831 bg->swap_extents++;
3832 spin_unlock(&bg->lock);
3833
3834 return ret;
3835}
3836
3837void btrfs_dec_block_group_swap_extents(struct btrfs_block_group *bg, int amount)
3838{
3839 spin_lock(&bg->lock);
3840 ASSERT(!bg->ro);
3841 ASSERT(bg->swap_extents >= amount);
3842 bg->swap_extents -= amount;
3843 spin_unlock(&bg->lock);
3844}