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
26 int 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 */
43 static 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 */
72 static 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
121 u64 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
141 void btrfs_get_block_group(struct btrfs_block_group *cache)
142 {
143 refcount_inc(&cache->refs);
144 }
145
146 void 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 */
179 static 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 */
219 static 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 */
259 struct 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 */
268 struct 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
274 struct 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 */
316 struct 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 */
353 void 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
362 void btrfs_wait_nocow_writers(struct btrfs_block_group *bg)
363 {
364 wait_var_event(&bg->nocow_writers, !atomic_read(&bg->nocow_writers));
365 }
366
367 void 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
379 void 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
404 struct 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
421 static void 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 */
440 void 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
465 static 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
472 static 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
486 static 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 */
519 int 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 */
580 static 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 */
669 static 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 }
698 out:
699 return ret;
700 }
701
702 static 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
746 next:
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);
833 out:
834 btrfs_free_path(path);
835 return ret;
836 }
837
838 static 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
844 static 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);
888 done:
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
918 int 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);
963 out:
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
972 static 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 */
995 static 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
1025 static struct btrfs_root *btrfs_block_group_root(struct btrfs_fs_info *fs_info)
1026 {
1027 if (btrfs_fs_compat_ro(fs_info, BLOCK_GROUP_TREE))
1028 return fs_info->block_group_root;
1029 return btrfs_extent_root(fs_info, 0);
1030 }
1031
1032 static int remove_block_group_item(struct btrfs_trans_handle *trans,
1033 struct btrfs_path *path,
1034 struct btrfs_block_group *block_group)
1035 {
1036 struct btrfs_fs_info *fs_info = trans->fs_info;
1037 struct btrfs_root *root;
1038 struct btrfs_key key;
1039 int ret;
1040
1041 root = btrfs_block_group_root(fs_info);
1042 key.objectid = block_group->start;
1043 key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
1044 key.offset = block_group->length;
1045
1046 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1047 if (ret > 0)
1048 ret = -ENOENT;
1049 if (ret < 0)
1050 return ret;
1051
1052 ret = btrfs_del_item(trans, root, path);
1053 return ret;
1054 }
1055
1056 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
1057 struct btrfs_chunk_map *map)
1058 {
1059 struct btrfs_fs_info *fs_info = trans->fs_info;
1060 struct btrfs_path *path;
1061 struct btrfs_block_group *block_group;
1062 struct btrfs_free_cluster *cluster;
1063 struct inode *inode;
1064 struct kobject *kobj = NULL;
1065 int ret;
1066 int index;
1067 int factor;
1068 struct btrfs_caching_control *caching_ctl = NULL;
1069 bool remove_map;
1070 bool remove_rsv = false;
1071
1072 block_group = btrfs_lookup_block_group(fs_info, map->start);
1073 if (!block_group)
1074 return -ENOENT;
1075
1076 BUG_ON(!block_group->ro);
1077
1078 trace_btrfs_remove_block_group(block_group);
1079 /*
1080 * Free the reserved super bytes from this block group before
1081 * remove it.
1082 */
1083 btrfs_free_excluded_extents(block_group);
1084 btrfs_free_ref_tree_range(fs_info, block_group->start,
1085 block_group->length);
1086
1087 index = btrfs_bg_flags_to_raid_index(block_group->flags);
1088 factor = btrfs_bg_type_to_factor(block_group->flags);
1089
1090 /* make sure this block group isn't part of an allocation cluster */
1091 cluster = &fs_info->data_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 /*
1097 * make sure this block group isn't part of a metadata
1098 * allocation cluster
1099 */
1100 cluster = &fs_info->meta_alloc_cluster;
1101 spin_lock(&cluster->refill_lock);
1102 btrfs_return_cluster_to_free_space(block_group, cluster);
1103 spin_unlock(&cluster->refill_lock);
1104
1105 btrfs_clear_treelog_bg(block_group);
1106 btrfs_clear_data_reloc_bg(block_group);
1107
1108 path = btrfs_alloc_path();
1109 if (!path) {
1110 ret = -ENOMEM;
1111 goto out;
1112 }
1113
1114 /*
1115 * get the inode first so any iput calls done for the io_list
1116 * aren't the final iput (no unlinks allowed now)
1117 */
1118 inode = lookup_free_space_inode(block_group, path);
1119
1120 mutex_lock(&trans->transaction->cache_write_mutex);
1121 /*
1122 * Make sure our free space cache IO is done before removing the
1123 * free space inode
1124 */
1125 spin_lock(&trans->transaction->dirty_bgs_lock);
1126 if (!list_empty(&block_group->io_list)) {
1127 list_del_init(&block_group->io_list);
1128
1129 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
1130
1131 spin_unlock(&trans->transaction->dirty_bgs_lock);
1132 btrfs_wait_cache_io(trans, block_group, path);
1133 btrfs_put_block_group(block_group);
1134 spin_lock(&trans->transaction->dirty_bgs_lock);
1135 }
1136
1137 if (!list_empty(&block_group->dirty_list)) {
1138 list_del_init(&block_group->dirty_list);
1139 remove_rsv = true;
1140 btrfs_put_block_group(block_group);
1141 }
1142 spin_unlock(&trans->transaction->dirty_bgs_lock);
1143 mutex_unlock(&trans->transaction->cache_write_mutex);
1144
1145 ret = btrfs_remove_free_space_inode(trans, inode, block_group);
1146 if (ret)
1147 goto out;
1148
1149 write_lock(&fs_info->block_group_cache_lock);
1150 rb_erase_cached(&block_group->cache_node,
1151 &fs_info->block_group_cache_tree);
1152 RB_CLEAR_NODE(&block_group->cache_node);
1153
1154 /* Once for the block groups rbtree */
1155 btrfs_put_block_group(block_group);
1156
1157 write_unlock(&fs_info->block_group_cache_lock);
1158
1159 down_write(&block_group->space_info->groups_sem);
1160 /*
1161 * we must use list_del_init so people can check to see if they
1162 * are still on the list after taking the semaphore
1163 */
1164 list_del_init(&block_group->list);
1165 if (list_empty(&block_group->space_info->block_groups[index])) {
1166 kobj = block_group->space_info->block_group_kobjs[index];
1167 block_group->space_info->block_group_kobjs[index] = NULL;
1168 clear_avail_alloc_bits(fs_info, block_group->flags);
1169 }
1170 up_write(&block_group->space_info->groups_sem);
1171 clear_incompat_bg_bits(fs_info, block_group->flags);
1172 if (kobj) {
1173 kobject_del(kobj);
1174 kobject_put(kobj);
1175 }
1176
1177 if (block_group->cached == BTRFS_CACHE_STARTED)
1178 btrfs_wait_block_group_cache_done(block_group);
1179
1180 write_lock(&fs_info->block_group_cache_lock);
1181 caching_ctl = btrfs_get_caching_control(block_group);
1182 if (!caching_ctl) {
1183 struct btrfs_caching_control *ctl;
1184
1185 list_for_each_entry(ctl, &fs_info->caching_block_groups, list) {
1186 if (ctl->block_group == block_group) {
1187 caching_ctl = ctl;
1188 refcount_inc(&caching_ctl->count);
1189 break;
1190 }
1191 }
1192 }
1193 if (caching_ctl)
1194 list_del_init(&caching_ctl->list);
1195 write_unlock(&fs_info->block_group_cache_lock);
1196
1197 if (caching_ctl) {
1198 /* Once for the caching bgs list and once for us. */
1199 btrfs_put_caching_control(caching_ctl);
1200 btrfs_put_caching_control(caching_ctl);
1201 }
1202
1203 spin_lock(&trans->transaction->dirty_bgs_lock);
1204 WARN_ON(!list_empty(&block_group->dirty_list));
1205 WARN_ON(!list_empty(&block_group->io_list));
1206 spin_unlock(&trans->transaction->dirty_bgs_lock);
1207
1208 btrfs_remove_free_space_cache(block_group);
1209
1210 spin_lock(&block_group->space_info->lock);
1211 list_del_init(&block_group->ro_list);
1212
1213 if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
1214 WARN_ON(block_group->space_info->total_bytes
1215 < block_group->length);
1216 WARN_ON(block_group->space_info->bytes_readonly
1217 < block_group->length - block_group->zone_unusable);
1218 WARN_ON(block_group->space_info->bytes_zone_unusable
1219 < block_group->zone_unusable);
1220 WARN_ON(block_group->space_info->disk_total
1221 < block_group->length * factor);
1222 }
1223 block_group->space_info->total_bytes -= block_group->length;
1224 block_group->space_info->bytes_readonly -=
1225 (block_group->length - block_group->zone_unusable);
1226 btrfs_space_info_update_bytes_zone_unusable(fs_info, block_group->space_info,
1227 -block_group->zone_unusable);
1228 block_group->space_info->disk_total -= block_group->length * factor;
1229
1230 spin_unlock(&block_group->space_info->lock);
1231
1232 /*
1233 * Remove the free space for the block group from the free space tree
1234 * and the block group's item from the extent tree before marking the
1235 * block group as removed. This is to prevent races with tasks that
1236 * freeze and unfreeze a block group, this task and another task
1237 * allocating a new block group - the unfreeze task ends up removing
1238 * the block group's extent map before the task calling this function
1239 * deletes the block group item from the extent tree, allowing for
1240 * another task to attempt to create another block group with the same
1241 * item key (and failing with -EEXIST and a transaction abort).
1242 */
1243 ret = remove_block_group_free_space(trans, block_group);
1244 if (ret)
1245 goto out;
1246
1247 ret = remove_block_group_item(trans, path, block_group);
1248 if (ret < 0)
1249 goto out;
1250
1251 spin_lock(&block_group->lock);
1252 set_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags);
1253
1254 /*
1255 * At this point trimming or scrub can't start on this block group,
1256 * because we removed the block group from the rbtree
1257 * fs_info->block_group_cache_tree so no one can't find it anymore and
1258 * even if someone already got this block group before we removed it
1259 * from the rbtree, they have already incremented block_group->frozen -
1260 * if they didn't, for the trimming case they won't find any free space
1261 * entries because we already removed them all when we called
1262 * btrfs_remove_free_space_cache().
1263 *
1264 * And we must not remove the chunk map from the fs_info->mapping_tree
1265 * to prevent the same logical address range and physical device space
1266 * ranges from being reused for a new block group. This is needed to
1267 * avoid races with trimming and scrub.
1268 *
1269 * An fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
1270 * completely transactionless, so while it is trimming a range the
1271 * currently running transaction might finish and a new one start,
1272 * allowing for new block groups to be created that can reuse the same
1273 * physical device locations unless we take this special care.
1274 *
1275 * There may also be an implicit trim operation if the file system
1276 * is mounted with -odiscard. The same protections must remain
1277 * in place until the extents have been discarded completely when
1278 * the transaction commit has completed.
1279 */
1280 remove_map = (atomic_read(&block_group->frozen) == 0);
1281 spin_unlock(&block_group->lock);
1282
1283 if (remove_map)
1284 btrfs_remove_chunk_map(fs_info, map);
1285
1286 out:
1287 /* Once for the lookup reference */
1288 btrfs_put_block_group(block_group);
1289 if (remove_rsv)
1290 btrfs_dec_delayed_refs_rsv_bg_updates(fs_info);
1291 btrfs_free_path(path);
1292 return ret;
1293 }
1294
1295 struct btrfs_trans_handle *btrfs_start_trans_remove_block_group(
1296 struct btrfs_fs_info *fs_info, const u64 chunk_offset)
1297 {
1298 struct btrfs_root *root = btrfs_block_group_root(fs_info);
1299 struct btrfs_chunk_map *map;
1300 unsigned int num_items;
1301
1302 map = btrfs_find_chunk_map(fs_info, chunk_offset, 1);
1303 ASSERT(map != NULL);
1304 ASSERT(map->start == chunk_offset);
1305
1306 /*
1307 * We need to reserve 3 + N units from the metadata space info in order
1308 * to remove a block group (done at btrfs_remove_chunk() and at
1309 * btrfs_remove_block_group()), which are used for:
1310 *
1311 * 1 unit for adding the free space inode's orphan (located in the tree
1312 * of tree roots).
1313 * 1 unit for deleting the block group item (located in the extent
1314 * tree).
1315 * 1 unit for deleting the free space item (located in tree of tree
1316 * roots).
1317 * N units for deleting N device extent items corresponding to each
1318 * stripe (located in the device tree).
1319 *
1320 * In order to remove a block group we also need to reserve units in the
1321 * system space info in order to update the chunk tree (update one or
1322 * more device items and remove one chunk item), but this is done at
1323 * btrfs_remove_chunk() through a call to check_system_chunk().
1324 */
1325 num_items = 3 + map->num_stripes;
1326 btrfs_free_chunk_map(map);
1327
1328 return btrfs_start_transaction_fallback_global_rsv(root, num_items);
1329 }
1330
1331 /*
1332 * Mark block group @cache read-only, so later write won't happen to block
1333 * group @cache.
1334 *
1335 * If @force is not set, this function will only mark the block group readonly
1336 * if we have enough free space (1M) in other metadata/system block groups.
1337 * If @force is not set, this function will mark the block group readonly
1338 * without checking free space.
1339 *
1340 * NOTE: This function doesn't care if other block groups can contain all the
1341 * data in this block group. That check should be done by relocation routine,
1342 * not this function.
1343 */
1344 static int inc_block_group_ro(struct btrfs_block_group *cache, int force)
1345 {
1346 struct btrfs_space_info *sinfo = cache->space_info;
1347 u64 num_bytes;
1348 int ret = -ENOSPC;
1349
1350 spin_lock(&sinfo->lock);
1351 spin_lock(&cache->lock);
1352
1353 if (cache->swap_extents) {
1354 ret = -ETXTBSY;
1355 goto out;
1356 }
1357
1358 if (cache->ro) {
1359 cache->ro++;
1360 ret = 0;
1361 goto out;
1362 }
1363
1364 num_bytes = cache->length - cache->reserved - cache->pinned -
1365 cache->bytes_super - cache->zone_unusable - cache->used;
1366
1367 /*
1368 * Data never overcommits, even in mixed mode, so do just the straight
1369 * check of left over space in how much we have allocated.
1370 */
1371 if (force) {
1372 ret = 0;
1373 } else if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA) {
1374 u64 sinfo_used = btrfs_space_info_used(sinfo, true);
1375
1376 /*
1377 * Here we make sure if we mark this bg RO, we still have enough
1378 * free space as buffer.
1379 */
1380 if (sinfo_used + num_bytes <= sinfo->total_bytes)
1381 ret = 0;
1382 } else {
1383 /*
1384 * We overcommit metadata, so we need to do the
1385 * btrfs_can_overcommit check here, and we need to pass in
1386 * BTRFS_RESERVE_NO_FLUSH to give ourselves the most amount of
1387 * leeway to allow us to mark this block group as read only.
1388 */
1389 if (btrfs_can_overcommit(cache->fs_info, sinfo, num_bytes,
1390 BTRFS_RESERVE_NO_FLUSH))
1391 ret = 0;
1392 }
1393
1394 if (!ret) {
1395 sinfo->bytes_readonly += num_bytes;
1396 if (btrfs_is_zoned(cache->fs_info)) {
1397 /* Migrate zone_unusable bytes to readonly */
1398 sinfo->bytes_readonly += cache->zone_unusable;
1399 btrfs_space_info_update_bytes_zone_unusable(cache->fs_info, sinfo,
1400 -cache->zone_unusable);
1401 cache->zone_unusable = 0;
1402 }
1403 cache->ro++;
1404 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
1405 }
1406 out:
1407 spin_unlock(&cache->lock);
1408 spin_unlock(&sinfo->lock);
1409 if (ret == -ENOSPC && btrfs_test_opt(cache->fs_info, ENOSPC_DEBUG)) {
1410 btrfs_info(cache->fs_info,
1411 "unable to make block group %llu ro", cache->start);
1412 btrfs_dump_space_info(cache->fs_info, cache->space_info, 0, 0);
1413 }
1414 return ret;
1415 }
1416
1417 static bool clean_pinned_extents(struct btrfs_trans_handle *trans,
1418 struct btrfs_block_group *bg)
1419 {
1420 struct btrfs_fs_info *fs_info = bg->fs_info;
1421 struct btrfs_transaction *prev_trans = NULL;
1422 const u64 start = bg->start;
1423 const u64 end = start + bg->length - 1;
1424 int ret;
1425
1426 spin_lock(&fs_info->trans_lock);
1427 if (trans->transaction->list.prev != &fs_info->trans_list) {
1428 prev_trans = list_last_entry(&trans->transaction->list,
1429 struct btrfs_transaction, list);
1430 refcount_inc(&prev_trans->use_count);
1431 }
1432 spin_unlock(&fs_info->trans_lock);
1433
1434 /*
1435 * Hold the unused_bg_unpin_mutex lock to avoid racing with
1436 * btrfs_finish_extent_commit(). If we are at transaction N, another
1437 * task might be running finish_extent_commit() for the previous
1438 * transaction N - 1, and have seen a range belonging to the block
1439 * group in pinned_extents before we were able to clear the whole block
1440 * group range from pinned_extents. This means that task can lookup for
1441 * the block group after we unpinned it from pinned_extents and removed
1442 * it, leading to an error at unpin_extent_range().
1443 */
1444 mutex_lock(&fs_info->unused_bg_unpin_mutex);
1445 if (prev_trans) {
1446 ret = clear_extent_bits(&prev_trans->pinned_extents, start, end,
1447 EXTENT_DIRTY);
1448 if (ret)
1449 goto out;
1450 }
1451
1452 ret = clear_extent_bits(&trans->transaction->pinned_extents, start, end,
1453 EXTENT_DIRTY);
1454 out:
1455 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
1456 if (prev_trans)
1457 btrfs_put_transaction(prev_trans);
1458
1459 return ret == 0;
1460 }
1461
1462 /*
1463 * Process the unused_bgs list and remove any that don't have any allocated
1464 * space inside of them.
1465 */
1466 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
1467 {
1468 LIST_HEAD(retry_list);
1469 struct btrfs_block_group *block_group;
1470 struct btrfs_space_info *space_info;
1471 struct btrfs_trans_handle *trans;
1472 const bool async_trim_enabled = btrfs_test_opt(fs_info, DISCARD_ASYNC);
1473 int ret = 0;
1474
1475 if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
1476 return;
1477
1478 if (btrfs_fs_closing(fs_info))
1479 return;
1480
1481 /*
1482 * Long running balances can keep us blocked here for eternity, so
1483 * simply skip deletion if we're unable to get the mutex.
1484 */
1485 if (!mutex_trylock(&fs_info->reclaim_bgs_lock))
1486 return;
1487
1488 spin_lock(&fs_info->unused_bgs_lock);
1489 while (!list_empty(&fs_info->unused_bgs)) {
1490 u64 used;
1491 int trimming;
1492
1493 block_group = list_first_entry(&fs_info->unused_bgs,
1494 struct btrfs_block_group,
1495 bg_list);
1496 list_del_init(&block_group->bg_list);
1497
1498 space_info = block_group->space_info;
1499
1500 if (ret || btrfs_mixed_space_info(space_info)) {
1501 btrfs_put_block_group(block_group);
1502 continue;
1503 }
1504 spin_unlock(&fs_info->unused_bgs_lock);
1505
1506 btrfs_discard_cancel_work(&fs_info->discard_ctl, block_group);
1507
1508 /* Don't want to race with allocators so take the groups_sem */
1509 down_write(&space_info->groups_sem);
1510
1511 /*
1512 * Async discard moves the final block group discard to be prior
1513 * to the unused_bgs code path. Therefore, if it's not fully
1514 * trimmed, punt it back to the async discard lists.
1515 */
1516 if (btrfs_test_opt(fs_info, DISCARD_ASYNC) &&
1517 !btrfs_is_free_space_trimmed(block_group)) {
1518 trace_btrfs_skip_unused_block_group(block_group);
1519 up_write(&space_info->groups_sem);
1520 /* Requeue if we failed because of async discard */
1521 btrfs_discard_queue_work(&fs_info->discard_ctl,
1522 block_group);
1523 goto next;
1524 }
1525
1526 spin_lock(&space_info->lock);
1527 spin_lock(&block_group->lock);
1528 if (btrfs_is_block_group_used(block_group) || block_group->ro ||
1529 list_is_singular(&block_group->list)) {
1530 /*
1531 * We want to bail if we made new allocations or have
1532 * outstanding allocations in this block group. We do
1533 * the ro check in case balance is currently acting on
1534 * this block group.
1535 *
1536 * Also bail out if this is the only block group for its
1537 * type, because otherwise we would lose profile
1538 * information from fs_info->avail_*_alloc_bits and the
1539 * next block group of this type would be created with a
1540 * "single" profile (even if we're in a raid fs) because
1541 * fs_info->avail_*_alloc_bits would be 0.
1542 */
1543 trace_btrfs_skip_unused_block_group(block_group);
1544 spin_unlock(&block_group->lock);
1545 spin_unlock(&space_info->lock);
1546 up_write(&space_info->groups_sem);
1547 goto next;
1548 }
1549
1550 /*
1551 * The block group may be unused but there may be space reserved
1552 * accounting with the existence of that block group, that is,
1553 * space_info->bytes_may_use was incremented by a task but no
1554 * space was yet allocated from the block group by the task.
1555 * That space may or may not be allocated, as we are generally
1556 * pessimistic about space reservation for metadata as well as
1557 * for data when using compression (as we reserve space based on
1558 * the worst case, when data can't be compressed, and before
1559 * actually attempting compression, before starting writeback).
1560 *
1561 * So check if the total space of the space_info minus the size
1562 * of this block group is less than the used space of the
1563 * space_info - if that's the case, then it means we have tasks
1564 * that might be relying on the block group in order to allocate
1565 * extents, and add back the block group to the unused list when
1566 * we finish, so that we retry later in case no tasks ended up
1567 * needing to allocate extents from the block group.
1568 */
1569 used = btrfs_space_info_used(space_info, true);
1570 if (space_info->total_bytes - block_group->length < used &&
1571 block_group->zone_unusable < block_group->length) {
1572 /*
1573 * Add a reference for the list, compensate for the ref
1574 * drop under the "next" label for the
1575 * fs_info->unused_bgs list.
1576 */
1577 btrfs_get_block_group(block_group);
1578 list_add_tail(&block_group->bg_list, &retry_list);
1579
1580 trace_btrfs_skip_unused_block_group(block_group);
1581 spin_unlock(&block_group->lock);
1582 spin_unlock(&space_info->lock);
1583 up_write(&space_info->groups_sem);
1584 goto next;
1585 }
1586
1587 spin_unlock(&block_group->lock);
1588 spin_unlock(&space_info->lock);
1589
1590 /* We don't want to force the issue, only flip if it's ok. */
1591 ret = inc_block_group_ro(block_group, 0);
1592 up_write(&space_info->groups_sem);
1593 if (ret < 0) {
1594 ret = 0;
1595 goto next;
1596 }
1597
1598 ret = btrfs_zone_finish(block_group);
1599 if (ret < 0) {
1600 btrfs_dec_block_group_ro(block_group);
1601 if (ret == -EAGAIN)
1602 ret = 0;
1603 goto next;
1604 }
1605
1606 /*
1607 * Want to do this before we do anything else so we can recover
1608 * properly if we fail to join the transaction.
1609 */
1610 trans = btrfs_start_trans_remove_block_group(fs_info,
1611 block_group->start);
1612 if (IS_ERR(trans)) {
1613 btrfs_dec_block_group_ro(block_group);
1614 ret = PTR_ERR(trans);
1615 goto next;
1616 }
1617
1618 /*
1619 * We could have pending pinned extents for this block group,
1620 * just delete them, we don't care about them anymore.
1621 */
1622 if (!clean_pinned_extents(trans, block_group)) {
1623 btrfs_dec_block_group_ro(block_group);
1624 goto end_trans;
1625 }
1626
1627 /*
1628 * At this point, the block_group is read only and should fail
1629 * new allocations. However, btrfs_finish_extent_commit() can
1630 * cause this block_group to be placed back on the discard
1631 * lists because now the block_group isn't fully discarded.
1632 * Bail here and try again later after discarding everything.
1633 */
1634 spin_lock(&fs_info->discard_ctl.lock);
1635 if (!list_empty(&block_group->discard_list)) {
1636 spin_unlock(&fs_info->discard_ctl.lock);
1637 btrfs_dec_block_group_ro(block_group);
1638 btrfs_discard_queue_work(&fs_info->discard_ctl,
1639 block_group);
1640 goto end_trans;
1641 }
1642 spin_unlock(&fs_info->discard_ctl.lock);
1643
1644 /* Reset pinned so btrfs_put_block_group doesn't complain */
1645 spin_lock(&space_info->lock);
1646 spin_lock(&block_group->lock);
1647
1648 btrfs_space_info_update_bytes_pinned(fs_info, space_info,
1649 -block_group->pinned);
1650 space_info->bytes_readonly += block_group->pinned;
1651 block_group->pinned = 0;
1652
1653 spin_unlock(&block_group->lock);
1654 spin_unlock(&space_info->lock);
1655
1656 /*
1657 * The normal path here is an unused block group is passed here,
1658 * then trimming is handled in the transaction commit path.
1659 * Async discard interposes before this to do the trimming
1660 * before coming down the unused block group path as trimming
1661 * will no longer be done later in the transaction commit path.
1662 */
1663 if (!async_trim_enabled && btrfs_test_opt(fs_info, DISCARD_ASYNC))
1664 goto flip_async;
1665
1666 /*
1667 * DISCARD can flip during remount. On zoned filesystems, we
1668 * need to reset sequential-required zones.
1669 */
1670 trimming = btrfs_test_opt(fs_info, DISCARD_SYNC) ||
1671 btrfs_is_zoned(fs_info);
1672
1673 /* Implicit trim during transaction commit. */
1674 if (trimming)
1675 btrfs_freeze_block_group(block_group);
1676
1677 /*
1678 * Btrfs_remove_chunk will abort the transaction if things go
1679 * horribly wrong.
1680 */
1681 ret = btrfs_remove_chunk(trans, block_group->start);
1682
1683 if (ret) {
1684 if (trimming)
1685 btrfs_unfreeze_block_group(block_group);
1686 goto end_trans;
1687 }
1688
1689 /*
1690 * If we're not mounted with -odiscard, we can just forget
1691 * about this block group. Otherwise we'll need to wait
1692 * until transaction commit to do the actual discard.
1693 */
1694 if (trimming) {
1695 spin_lock(&fs_info->unused_bgs_lock);
1696 /*
1697 * A concurrent scrub might have added us to the list
1698 * fs_info->unused_bgs, so use a list_move operation
1699 * to add the block group to the deleted_bgs list.
1700 */
1701 list_move(&block_group->bg_list,
1702 &trans->transaction->deleted_bgs);
1703 spin_unlock(&fs_info->unused_bgs_lock);
1704 btrfs_get_block_group(block_group);
1705 }
1706 end_trans:
1707 btrfs_end_transaction(trans);
1708 next:
1709 btrfs_put_block_group(block_group);
1710 spin_lock(&fs_info->unused_bgs_lock);
1711 }
1712 list_splice_tail(&retry_list, &fs_info->unused_bgs);
1713 spin_unlock(&fs_info->unused_bgs_lock);
1714 mutex_unlock(&fs_info->reclaim_bgs_lock);
1715 return;
1716
1717 flip_async:
1718 btrfs_end_transaction(trans);
1719 spin_lock(&fs_info->unused_bgs_lock);
1720 list_splice_tail(&retry_list, &fs_info->unused_bgs);
1721 spin_unlock(&fs_info->unused_bgs_lock);
1722 mutex_unlock(&fs_info->reclaim_bgs_lock);
1723 btrfs_put_block_group(block_group);
1724 btrfs_discard_punt_unused_bgs_list(fs_info);
1725 }
1726
1727 void btrfs_mark_bg_unused(struct btrfs_block_group *bg)
1728 {
1729 struct btrfs_fs_info *fs_info = bg->fs_info;
1730
1731 spin_lock(&fs_info->unused_bgs_lock);
1732 if (list_empty(&bg->bg_list)) {
1733 btrfs_get_block_group(bg);
1734 trace_btrfs_add_unused_block_group(bg);
1735 list_add_tail(&bg->bg_list, &fs_info->unused_bgs);
1736 } else if (!test_bit(BLOCK_GROUP_FLAG_NEW, &bg->runtime_flags)) {
1737 /* Pull out the block group from the reclaim_bgs list. */
1738 trace_btrfs_add_unused_block_group(bg);
1739 list_move_tail(&bg->bg_list, &fs_info->unused_bgs);
1740 }
1741 spin_unlock(&fs_info->unused_bgs_lock);
1742 }
1743
1744 /*
1745 * We want block groups with a low number of used bytes to be in the beginning
1746 * of the list, so they will get reclaimed first.
1747 */
1748 static int reclaim_bgs_cmp(void *unused, const struct list_head *a,
1749 const struct list_head *b)
1750 {
1751 const struct btrfs_block_group *bg1, *bg2;
1752
1753 bg1 = list_entry(a, struct btrfs_block_group, bg_list);
1754 bg2 = list_entry(b, struct btrfs_block_group, bg_list);
1755
1756 return bg1->used > bg2->used;
1757 }
1758
1759 static inline bool btrfs_should_reclaim(struct btrfs_fs_info *fs_info)
1760 {
1761 if (btrfs_is_zoned(fs_info))
1762 return btrfs_zoned_should_reclaim(fs_info);
1763 return true;
1764 }
1765
1766 static bool should_reclaim_block_group(struct btrfs_block_group *bg, u64 bytes_freed)
1767 {
1768 const int thresh_pct = btrfs_calc_reclaim_threshold(bg->space_info);
1769 u64 thresh_bytes = mult_perc(bg->length, thresh_pct);
1770 const u64 new_val = bg->used;
1771 const u64 old_val = new_val + bytes_freed;
1772
1773 if (thresh_bytes == 0)
1774 return false;
1775
1776 /*
1777 * If we were below the threshold before don't reclaim, we are likely a
1778 * brand new block group and we don't want to relocate new block groups.
1779 */
1780 if (old_val < thresh_bytes)
1781 return false;
1782 if (new_val >= thresh_bytes)
1783 return false;
1784 return true;
1785 }
1786
1787 void btrfs_reclaim_bgs_work(struct work_struct *work)
1788 {
1789 struct btrfs_fs_info *fs_info =
1790 container_of(work, struct btrfs_fs_info, reclaim_bgs_work);
1791 struct btrfs_block_group *bg;
1792 struct btrfs_space_info *space_info;
1793 LIST_HEAD(retry_list);
1794
1795 if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
1796 return;
1797
1798 if (btrfs_fs_closing(fs_info))
1799 return;
1800
1801 if (!btrfs_should_reclaim(fs_info))
1802 return;
1803
1804 sb_start_write(fs_info->sb);
1805
1806 if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_BALANCE)) {
1807 sb_end_write(fs_info->sb);
1808 return;
1809 }
1810
1811 /*
1812 * Long running balances can keep us blocked here for eternity, so
1813 * simply skip reclaim if we're unable to get the mutex.
1814 */
1815 if (!mutex_trylock(&fs_info->reclaim_bgs_lock)) {
1816 btrfs_exclop_finish(fs_info);
1817 sb_end_write(fs_info->sb);
1818 return;
1819 }
1820
1821 spin_lock(&fs_info->unused_bgs_lock);
1822 /*
1823 * Sort happens under lock because we can't simply splice it and sort.
1824 * The block groups might still be in use and reachable via bg_list,
1825 * and their presence in the reclaim_bgs list must be preserved.
1826 */
1827 list_sort(NULL, &fs_info->reclaim_bgs, reclaim_bgs_cmp);
1828 while (!list_empty(&fs_info->reclaim_bgs)) {
1829 u64 zone_unusable;
1830 u64 reclaimed;
1831 int ret = 0;
1832
1833 bg = list_first_entry(&fs_info->reclaim_bgs,
1834 struct btrfs_block_group,
1835 bg_list);
1836 list_del_init(&bg->bg_list);
1837
1838 space_info = bg->space_info;
1839 spin_unlock(&fs_info->unused_bgs_lock);
1840
1841 /* Don't race with allocators so take the groups_sem */
1842 down_write(&space_info->groups_sem);
1843
1844 spin_lock(&space_info->lock);
1845 spin_lock(&bg->lock);
1846 if (bg->reserved || bg->pinned || bg->ro) {
1847 /*
1848 * We want to bail if we made new allocations or have
1849 * outstanding allocations in this block group. We do
1850 * the ro check in case balance is currently acting on
1851 * this block group.
1852 */
1853 spin_unlock(&bg->lock);
1854 spin_unlock(&space_info->lock);
1855 up_write(&space_info->groups_sem);
1856 goto next;
1857 }
1858 if (bg->used == 0) {
1859 /*
1860 * It is possible that we trigger relocation on a block
1861 * group as its extents are deleted and it first goes
1862 * below the threshold, then shortly after goes empty.
1863 *
1864 * In this case, relocating it does delete it, but has
1865 * some overhead in relocation specific metadata, looking
1866 * for the non-existent extents and running some extra
1867 * transactions, which we can avoid by using one of the
1868 * other mechanisms for dealing with empty block groups.
1869 */
1870 if (!btrfs_test_opt(fs_info, DISCARD_ASYNC))
1871 btrfs_mark_bg_unused(bg);
1872 spin_unlock(&bg->lock);
1873 spin_unlock(&space_info->lock);
1874 up_write(&space_info->groups_sem);
1875 goto next;
1876
1877 }
1878 /*
1879 * The block group might no longer meet the reclaim condition by
1880 * the time we get around to reclaiming it, so to avoid
1881 * reclaiming overly full block_groups, skip reclaiming them.
1882 *
1883 * Since the decision making process also depends on the amount
1884 * being freed, pass in a fake giant value to skip that extra
1885 * check, which is more meaningful when adding to the list in
1886 * the first place.
1887 */
1888 if (!should_reclaim_block_group(bg, bg->length)) {
1889 spin_unlock(&bg->lock);
1890 spin_unlock(&space_info->lock);
1891 up_write(&space_info->groups_sem);
1892 goto next;
1893 }
1894 spin_unlock(&bg->lock);
1895 spin_unlock(&space_info->lock);
1896
1897 /*
1898 * Get out fast, in case we're read-only or unmounting the
1899 * filesystem. It is OK to drop block groups from the list even
1900 * for the read-only case. As we did sb_start_write(),
1901 * "mount -o remount,ro" won't happen and read-only filesystem
1902 * means it is forced read-only due to a fatal error. So, it
1903 * never gets back to read-write to let us reclaim again.
1904 */
1905 if (btrfs_need_cleaner_sleep(fs_info)) {
1906 up_write(&space_info->groups_sem);
1907 goto next;
1908 }
1909
1910 /*
1911 * Cache the zone_unusable value before turning the block group
1912 * to read only. As soon as the blog group is read only it's
1913 * zone_unusable value gets moved to the block group's read-only
1914 * bytes and isn't available for calculations anymore.
1915 */
1916 zone_unusable = bg->zone_unusable;
1917 ret = inc_block_group_ro(bg, 0);
1918 up_write(&space_info->groups_sem);
1919 if (ret < 0)
1920 goto next;
1921
1922 btrfs_info(fs_info,
1923 "reclaiming chunk %llu with %llu%% used %llu%% unusable",
1924 bg->start,
1925 div64_u64(bg->used * 100, bg->length),
1926 div64_u64(zone_unusable * 100, bg->length));
1927 trace_btrfs_reclaim_block_group(bg);
1928 reclaimed = bg->used;
1929 ret = btrfs_relocate_chunk(fs_info, bg->start);
1930 if (ret) {
1931 btrfs_dec_block_group_ro(bg);
1932 btrfs_err(fs_info, "error relocating chunk %llu",
1933 bg->start);
1934 reclaimed = 0;
1935 spin_lock(&space_info->lock);
1936 space_info->reclaim_errors++;
1937 if (READ_ONCE(space_info->periodic_reclaim))
1938 space_info->periodic_reclaim_ready = false;
1939 spin_unlock(&space_info->lock);
1940 }
1941 spin_lock(&space_info->lock);
1942 space_info->reclaim_count++;
1943 space_info->reclaim_bytes += reclaimed;
1944 spin_unlock(&space_info->lock);
1945
1946 next:
1947 if (ret && !READ_ONCE(space_info->periodic_reclaim)) {
1948 /* Refcount held by the reclaim_bgs list after splice. */
1949 spin_lock(&fs_info->unused_bgs_lock);
1950 /*
1951 * This block group might be added to the unused list
1952 * during the above process. Move it back to the
1953 * reclaim list otherwise.
1954 */
1955 if (list_empty(&bg->bg_list)) {
1956 btrfs_get_block_group(bg);
1957 list_add_tail(&bg->bg_list, &retry_list);
1958 }
1959 spin_unlock(&fs_info->unused_bgs_lock);
1960 }
1961 btrfs_put_block_group(bg);
1962
1963 mutex_unlock(&fs_info->reclaim_bgs_lock);
1964 /*
1965 * Reclaiming all the block groups in the list can take really
1966 * long. Prioritize cleaning up unused block groups.
1967 */
1968 btrfs_delete_unused_bgs(fs_info);
1969 /*
1970 * If we are interrupted by a balance, we can just bail out. The
1971 * cleaner thread restart again if necessary.
1972 */
1973 if (!mutex_trylock(&fs_info->reclaim_bgs_lock))
1974 goto end;
1975 spin_lock(&fs_info->unused_bgs_lock);
1976 }
1977 spin_unlock(&fs_info->unused_bgs_lock);
1978 mutex_unlock(&fs_info->reclaim_bgs_lock);
1979 end:
1980 spin_lock(&fs_info->unused_bgs_lock);
1981 list_splice_tail(&retry_list, &fs_info->reclaim_bgs);
1982 spin_unlock(&fs_info->unused_bgs_lock);
1983 btrfs_exclop_finish(fs_info);
1984 sb_end_write(fs_info->sb);
1985 }
1986
1987 void btrfs_reclaim_bgs(struct btrfs_fs_info *fs_info)
1988 {
1989 btrfs_reclaim_sweep(fs_info);
1990 spin_lock(&fs_info->unused_bgs_lock);
1991 if (!list_empty(&fs_info->reclaim_bgs))
1992 queue_work(system_unbound_wq, &fs_info->reclaim_bgs_work);
1993 spin_unlock(&fs_info->unused_bgs_lock);
1994 }
1995
1996 void btrfs_mark_bg_to_reclaim(struct btrfs_block_group *bg)
1997 {
1998 struct btrfs_fs_info *fs_info = bg->fs_info;
1999
2000 spin_lock(&fs_info->unused_bgs_lock);
2001 if (list_empty(&bg->bg_list)) {
2002 btrfs_get_block_group(bg);
2003 trace_btrfs_add_reclaim_block_group(bg);
2004 list_add_tail(&bg->bg_list, &fs_info->reclaim_bgs);
2005 }
2006 spin_unlock(&fs_info->unused_bgs_lock);
2007 }
2008
2009 static int read_bg_from_eb(struct btrfs_fs_info *fs_info, struct btrfs_key *key,
2010 struct btrfs_path *path)
2011 {
2012 struct btrfs_chunk_map *map;
2013 struct btrfs_block_group_item bg;
2014 struct extent_buffer *leaf;
2015 int slot;
2016 u64 flags;
2017 int ret = 0;
2018
2019 slot = path->slots[0];
2020 leaf = path->nodes[0];
2021
2022 map = btrfs_find_chunk_map(fs_info, key->objectid, key->offset);
2023 if (!map) {
2024 btrfs_err(fs_info,
2025 "logical %llu len %llu found bg but no related chunk",
2026 key->objectid, key->offset);
2027 return -ENOENT;
2028 }
2029
2030 if (map->start != key->objectid || map->chunk_len != key->offset) {
2031 btrfs_err(fs_info,
2032 "block group %llu len %llu mismatch with chunk %llu len %llu",
2033 key->objectid, key->offset, map->start, map->chunk_len);
2034 ret = -EUCLEAN;
2035 goto out_free_map;
2036 }
2037
2038 read_extent_buffer(leaf, &bg, btrfs_item_ptr_offset(leaf, slot),
2039 sizeof(bg));
2040 flags = btrfs_stack_block_group_flags(&bg) &
2041 BTRFS_BLOCK_GROUP_TYPE_MASK;
2042
2043 if (flags != (map->type & BTRFS_BLOCK_GROUP_TYPE_MASK)) {
2044 btrfs_err(fs_info,
2045 "block group %llu len %llu type flags 0x%llx mismatch with chunk type flags 0x%llx",
2046 key->objectid, key->offset, flags,
2047 (BTRFS_BLOCK_GROUP_TYPE_MASK & map->type));
2048 ret = -EUCLEAN;
2049 }
2050
2051 out_free_map:
2052 btrfs_free_chunk_map(map);
2053 return ret;
2054 }
2055
2056 static int find_first_block_group(struct btrfs_fs_info *fs_info,
2057 struct btrfs_path *path,
2058 struct btrfs_key *key)
2059 {
2060 struct btrfs_root *root = btrfs_block_group_root(fs_info);
2061 int ret;
2062 struct btrfs_key found_key;
2063
2064 btrfs_for_each_slot(root, key, &found_key, path, ret) {
2065 if (found_key.objectid >= key->objectid &&
2066 found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
2067 return read_bg_from_eb(fs_info, &found_key, path);
2068 }
2069 }
2070 return ret;
2071 }
2072
2073 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
2074 {
2075 u64 extra_flags = chunk_to_extended(flags) &
2076 BTRFS_EXTENDED_PROFILE_MASK;
2077
2078 write_seqlock(&fs_info->profiles_lock);
2079 if (flags & BTRFS_BLOCK_GROUP_DATA)
2080 fs_info->avail_data_alloc_bits |= extra_flags;
2081 if (flags & BTRFS_BLOCK_GROUP_METADATA)
2082 fs_info->avail_metadata_alloc_bits |= extra_flags;
2083 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
2084 fs_info->avail_system_alloc_bits |= extra_flags;
2085 write_sequnlock(&fs_info->profiles_lock);
2086 }
2087
2088 /*
2089 * Map a physical disk address to a list of logical addresses.
2090 *
2091 * @fs_info: the filesystem
2092 * @chunk_start: logical address of block group
2093 * @physical: physical address to map to logical addresses
2094 * @logical: return array of logical addresses which map to @physical
2095 * @naddrs: length of @logical
2096 * @stripe_len: size of IO stripe for the given block group
2097 *
2098 * Maps a particular @physical disk address to a list of @logical addresses.
2099 * Used primarily to exclude those portions of a block group that contain super
2100 * block copies.
2101 */
2102 int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
2103 u64 physical, u64 **logical, int *naddrs, int *stripe_len)
2104 {
2105 struct btrfs_chunk_map *map;
2106 u64 *buf;
2107 u64 bytenr;
2108 u64 data_stripe_length;
2109 u64 io_stripe_size;
2110 int i, nr = 0;
2111 int ret = 0;
2112
2113 map = btrfs_get_chunk_map(fs_info, chunk_start, 1);
2114 if (IS_ERR(map))
2115 return -EIO;
2116
2117 data_stripe_length = map->stripe_size;
2118 io_stripe_size = BTRFS_STRIPE_LEN;
2119 chunk_start = map->start;
2120
2121 /* For RAID5/6 adjust to a full IO stripe length */
2122 if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
2123 io_stripe_size = btrfs_stripe_nr_to_offset(nr_data_stripes(map));
2124
2125 buf = kcalloc(map->num_stripes, sizeof(u64), GFP_NOFS);
2126 if (!buf) {
2127 ret = -ENOMEM;
2128 goto out;
2129 }
2130
2131 for (i = 0; i < map->num_stripes; i++) {
2132 bool already_inserted = false;
2133 u32 stripe_nr;
2134 u32 offset;
2135 int j;
2136
2137 if (!in_range(physical, map->stripes[i].physical,
2138 data_stripe_length))
2139 continue;
2140
2141 stripe_nr = (physical - map->stripes[i].physical) >>
2142 BTRFS_STRIPE_LEN_SHIFT;
2143 offset = (physical - map->stripes[i].physical) &
2144 BTRFS_STRIPE_LEN_MASK;
2145
2146 if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
2147 BTRFS_BLOCK_GROUP_RAID10))
2148 stripe_nr = div_u64(stripe_nr * map->num_stripes + i,
2149 map->sub_stripes);
2150 /*
2151 * The remaining case would be for RAID56, multiply by
2152 * nr_data_stripes(). Alternatively, just use rmap_len below
2153 * instead of map->stripe_len
2154 */
2155 bytenr = chunk_start + stripe_nr * io_stripe_size + offset;
2156
2157 /* Ensure we don't add duplicate addresses */
2158 for (j = 0; j < nr; j++) {
2159 if (buf[j] == bytenr) {
2160 already_inserted = true;
2161 break;
2162 }
2163 }
2164
2165 if (!already_inserted)
2166 buf[nr++] = bytenr;
2167 }
2168
2169 *logical = buf;
2170 *naddrs = nr;
2171 *stripe_len = io_stripe_size;
2172 out:
2173 btrfs_free_chunk_map(map);
2174 return ret;
2175 }
2176
2177 static int exclude_super_stripes(struct btrfs_block_group *cache)
2178 {
2179 struct btrfs_fs_info *fs_info = cache->fs_info;
2180 const bool zoned = btrfs_is_zoned(fs_info);
2181 u64 bytenr;
2182 u64 *logical;
2183 int stripe_len;
2184 int i, nr, ret;
2185
2186 if (cache->start < BTRFS_SUPER_INFO_OFFSET) {
2187 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->start;
2188 cache->bytes_super += stripe_len;
2189 ret = set_extent_bit(&fs_info->excluded_extents, cache->start,
2190 cache->start + stripe_len - 1,
2191 EXTENT_UPTODATE, NULL);
2192 if (ret)
2193 return ret;
2194 }
2195
2196 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
2197 bytenr = btrfs_sb_offset(i);
2198 ret = btrfs_rmap_block(fs_info, cache->start,
2199 bytenr, &logical, &nr, &stripe_len);
2200 if (ret)
2201 return ret;
2202
2203 /* Shouldn't have super stripes in sequential zones */
2204 if (zoned && nr) {
2205 kfree(logical);
2206 btrfs_err(fs_info,
2207 "zoned: block group %llu must not contain super block",
2208 cache->start);
2209 return -EUCLEAN;
2210 }
2211
2212 while (nr--) {
2213 u64 len = min_t(u64, stripe_len,
2214 cache->start + cache->length - logical[nr]);
2215
2216 cache->bytes_super += len;
2217 ret = set_extent_bit(&fs_info->excluded_extents, logical[nr],
2218 logical[nr] + len - 1,
2219 EXTENT_UPTODATE, NULL);
2220 if (ret) {
2221 kfree(logical);
2222 return ret;
2223 }
2224 }
2225
2226 kfree(logical);
2227 }
2228 return 0;
2229 }
2230
2231 static struct btrfs_block_group *btrfs_create_block_group_cache(
2232 struct btrfs_fs_info *fs_info, u64 start)
2233 {
2234 struct btrfs_block_group *cache;
2235
2236 cache = kzalloc(sizeof(*cache), GFP_NOFS);
2237 if (!cache)
2238 return NULL;
2239
2240 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
2241 GFP_NOFS);
2242 if (!cache->free_space_ctl) {
2243 kfree(cache);
2244 return NULL;
2245 }
2246
2247 cache->start = start;
2248
2249 cache->fs_info = fs_info;
2250 cache->full_stripe_len = btrfs_full_stripe_len(fs_info, start);
2251
2252 cache->discard_index = BTRFS_DISCARD_INDEX_UNUSED;
2253
2254 refcount_set(&cache->refs, 1);
2255 spin_lock_init(&cache->lock);
2256 init_rwsem(&cache->data_rwsem);
2257 INIT_LIST_HEAD(&cache->list);
2258 INIT_LIST_HEAD(&cache->cluster_list);
2259 INIT_LIST_HEAD(&cache->bg_list);
2260 INIT_LIST_HEAD(&cache->ro_list);
2261 INIT_LIST_HEAD(&cache->discard_list);
2262 INIT_LIST_HEAD(&cache->dirty_list);
2263 INIT_LIST_HEAD(&cache->io_list);
2264 INIT_LIST_HEAD(&cache->active_bg_list);
2265 btrfs_init_free_space_ctl(cache, cache->free_space_ctl);
2266 atomic_set(&cache->frozen, 0);
2267 mutex_init(&cache->free_space_lock);
2268
2269 return cache;
2270 }
2271
2272 /*
2273 * Iterate all chunks and verify that each of them has the corresponding block
2274 * group
2275 */
2276 static int check_chunk_block_group_mappings(struct btrfs_fs_info *fs_info)
2277 {
2278 u64 start = 0;
2279 int ret = 0;
2280
2281 while (1) {
2282 struct btrfs_chunk_map *map;
2283 struct btrfs_block_group *bg;
2284
2285 /*
2286 * btrfs_find_chunk_map() will return the first chunk map
2287 * intersecting the range, so setting @length to 1 is enough to
2288 * get the first chunk.
2289 */
2290 map = btrfs_find_chunk_map(fs_info, start, 1);
2291 if (!map)
2292 break;
2293
2294 bg = btrfs_lookup_block_group(fs_info, map->start);
2295 if (!bg) {
2296 btrfs_err(fs_info,
2297 "chunk start=%llu len=%llu doesn't have corresponding block group",
2298 map->start, map->chunk_len);
2299 ret = -EUCLEAN;
2300 btrfs_free_chunk_map(map);
2301 break;
2302 }
2303 if (bg->start != map->start || bg->length != map->chunk_len ||
2304 (bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK) !=
2305 (map->type & BTRFS_BLOCK_GROUP_TYPE_MASK)) {
2306 btrfs_err(fs_info,
2307 "chunk start=%llu len=%llu flags=0x%llx doesn't match block group start=%llu len=%llu flags=0x%llx",
2308 map->start, map->chunk_len,
2309 map->type & BTRFS_BLOCK_GROUP_TYPE_MASK,
2310 bg->start, bg->length,
2311 bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK);
2312 ret = -EUCLEAN;
2313 btrfs_free_chunk_map(map);
2314 btrfs_put_block_group(bg);
2315 break;
2316 }
2317 start = map->start + map->chunk_len;
2318 btrfs_free_chunk_map(map);
2319 btrfs_put_block_group(bg);
2320 }
2321 return ret;
2322 }
2323
2324 static int read_one_block_group(struct btrfs_fs_info *info,
2325 struct btrfs_block_group_item *bgi,
2326 const struct btrfs_key *key,
2327 int need_clear)
2328 {
2329 struct btrfs_block_group *cache;
2330 const bool mixed = btrfs_fs_incompat(info, MIXED_GROUPS);
2331 int ret;
2332
2333 ASSERT(key->type == BTRFS_BLOCK_GROUP_ITEM_KEY);
2334
2335 cache = btrfs_create_block_group_cache(info, key->objectid);
2336 if (!cache)
2337 return -ENOMEM;
2338
2339 cache->length = key->offset;
2340 cache->used = btrfs_stack_block_group_used(bgi);
2341 cache->commit_used = cache->used;
2342 cache->flags = btrfs_stack_block_group_flags(bgi);
2343 cache->global_root_id = btrfs_stack_block_group_chunk_objectid(bgi);
2344
2345 set_free_space_tree_thresholds(cache);
2346
2347 if (need_clear) {
2348 /*
2349 * When we mount with old space cache, we need to
2350 * set BTRFS_DC_CLEAR and set dirty flag.
2351 *
2352 * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
2353 * truncate the old free space cache inode and
2354 * setup a new one.
2355 * b) Setting 'dirty flag' makes sure that we flush
2356 * the new space cache info onto disk.
2357 */
2358 if (btrfs_test_opt(info, SPACE_CACHE))
2359 cache->disk_cache_state = BTRFS_DC_CLEAR;
2360 }
2361 if (!mixed && ((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
2362 (cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
2363 btrfs_err(info,
2364 "bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
2365 cache->start);
2366 ret = -EINVAL;
2367 goto error;
2368 }
2369
2370 ret = btrfs_load_block_group_zone_info(cache, false);
2371 if (ret) {
2372 btrfs_err(info, "zoned: failed to load zone info of bg %llu",
2373 cache->start);
2374 goto error;
2375 }
2376
2377 /*
2378 * We need to exclude the super stripes now so that the space info has
2379 * super bytes accounted for, otherwise we'll think we have more space
2380 * than we actually do.
2381 */
2382 ret = exclude_super_stripes(cache);
2383 if (ret) {
2384 /* We may have excluded something, so call this just in case. */
2385 btrfs_free_excluded_extents(cache);
2386 goto error;
2387 }
2388
2389 /*
2390 * For zoned filesystem, space after the allocation offset is the only
2391 * free space for a block group. So, we don't need any caching work.
2392 * btrfs_calc_zone_unusable() will set the amount of free space and
2393 * zone_unusable space.
2394 *
2395 * For regular filesystem, check for two cases, either we are full, and
2396 * therefore don't need to bother with the caching work since we won't
2397 * find any space, or we are empty, and we can just add all the space
2398 * in and be done with it. This saves us _a_lot_ of time, particularly
2399 * in the full case.
2400 */
2401 if (btrfs_is_zoned(info)) {
2402 btrfs_calc_zone_unusable(cache);
2403 /* Should not have any excluded extents. Just in case, though. */
2404 btrfs_free_excluded_extents(cache);
2405 } else if (cache->length == cache->used) {
2406 cache->cached = BTRFS_CACHE_FINISHED;
2407 btrfs_free_excluded_extents(cache);
2408 } else if (cache->used == 0) {
2409 cache->cached = BTRFS_CACHE_FINISHED;
2410 ret = btrfs_add_new_free_space(cache, cache->start,
2411 cache->start + cache->length, NULL);
2412 btrfs_free_excluded_extents(cache);
2413 if (ret)
2414 goto error;
2415 }
2416
2417 ret = btrfs_add_block_group_cache(info, cache);
2418 if (ret) {
2419 btrfs_remove_free_space_cache(cache);
2420 goto error;
2421 }
2422 trace_btrfs_add_block_group(info, cache, 0);
2423 btrfs_add_bg_to_space_info(info, cache);
2424
2425 set_avail_alloc_bits(info, cache->flags);
2426 if (btrfs_chunk_writeable(info, cache->start)) {
2427 if (cache->used == 0) {
2428 ASSERT(list_empty(&cache->bg_list));
2429 if (btrfs_test_opt(info, DISCARD_ASYNC))
2430 btrfs_discard_queue_work(&info->discard_ctl, cache);
2431 else
2432 btrfs_mark_bg_unused(cache);
2433 }
2434 } else {
2435 inc_block_group_ro(cache, 1);
2436 }
2437
2438 return 0;
2439 error:
2440 btrfs_put_block_group(cache);
2441 return ret;
2442 }
2443
2444 static int fill_dummy_bgs(struct btrfs_fs_info *fs_info)
2445 {
2446 struct rb_node *node;
2447 int ret = 0;
2448
2449 for (node = rb_first_cached(&fs_info->mapping_tree); node; node = rb_next(node)) {
2450 struct btrfs_chunk_map *map;
2451 struct btrfs_block_group *bg;
2452
2453 map = rb_entry(node, struct btrfs_chunk_map, rb_node);
2454 bg = btrfs_create_block_group_cache(fs_info, map->start);
2455 if (!bg) {
2456 ret = -ENOMEM;
2457 break;
2458 }
2459
2460 /* Fill dummy cache as FULL */
2461 bg->length = map->chunk_len;
2462 bg->flags = map->type;
2463 bg->cached = BTRFS_CACHE_FINISHED;
2464 bg->used = map->chunk_len;
2465 bg->flags = map->type;
2466 ret = btrfs_add_block_group_cache(fs_info, bg);
2467 /*
2468 * We may have some valid block group cache added already, in
2469 * that case we skip to the next one.
2470 */
2471 if (ret == -EEXIST) {
2472 ret = 0;
2473 btrfs_put_block_group(bg);
2474 continue;
2475 }
2476
2477 if (ret) {
2478 btrfs_remove_free_space_cache(bg);
2479 btrfs_put_block_group(bg);
2480 break;
2481 }
2482
2483 btrfs_add_bg_to_space_info(fs_info, bg);
2484
2485 set_avail_alloc_bits(fs_info, bg->flags);
2486 }
2487 if (!ret)
2488 btrfs_init_global_block_rsv(fs_info);
2489 return ret;
2490 }
2491
2492 int btrfs_read_block_groups(struct btrfs_fs_info *info)
2493 {
2494 struct btrfs_root *root = btrfs_block_group_root(info);
2495 struct btrfs_path *path;
2496 int ret;
2497 struct btrfs_block_group *cache;
2498 struct btrfs_space_info *space_info;
2499 struct btrfs_key key;
2500 int need_clear = 0;
2501 u64 cache_gen;
2502
2503 /*
2504 * Either no extent root (with ibadroots rescue option) or we have
2505 * unsupported RO options. The fs can never be mounted read-write, so no
2506 * need to waste time searching block group items.
2507 *
2508 * This also allows new extent tree related changes to be RO compat,
2509 * no need for a full incompat flag.
2510 */
2511 if (!root || (btrfs_super_compat_ro_flags(info->super_copy) &
2512 ~BTRFS_FEATURE_COMPAT_RO_SUPP))
2513 return fill_dummy_bgs(info);
2514
2515 key.objectid = 0;
2516 key.offset = 0;
2517 key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
2518 path = btrfs_alloc_path();
2519 if (!path)
2520 return -ENOMEM;
2521
2522 cache_gen = btrfs_super_cache_generation(info->super_copy);
2523 if (btrfs_test_opt(info, SPACE_CACHE) &&
2524 btrfs_super_generation(info->super_copy) != cache_gen)
2525 need_clear = 1;
2526 if (btrfs_test_opt(info, CLEAR_CACHE))
2527 need_clear = 1;
2528
2529 while (1) {
2530 struct btrfs_block_group_item bgi;
2531 struct extent_buffer *leaf;
2532 int slot;
2533
2534 ret = find_first_block_group(info, path, &key);
2535 if (ret > 0)
2536 break;
2537 if (ret != 0)
2538 goto error;
2539
2540 leaf = path->nodes[0];
2541 slot = path->slots[0];
2542
2543 read_extent_buffer(leaf, &bgi, btrfs_item_ptr_offset(leaf, slot),
2544 sizeof(bgi));
2545
2546 btrfs_item_key_to_cpu(leaf, &key, slot);
2547 btrfs_release_path(path);
2548 ret = read_one_block_group(info, &bgi, &key, need_clear);
2549 if (ret < 0)
2550 goto error;
2551 key.objectid += key.offset;
2552 key.offset = 0;
2553 }
2554 btrfs_release_path(path);
2555
2556 list_for_each_entry(space_info, &info->space_info, list) {
2557 int i;
2558
2559 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2560 if (list_empty(&space_info->block_groups[i]))
2561 continue;
2562 cache = list_first_entry(&space_info->block_groups[i],
2563 struct btrfs_block_group,
2564 list);
2565 btrfs_sysfs_add_block_group_type(cache);
2566 }
2567
2568 if (!(btrfs_get_alloc_profile(info, space_info->flags) &
2569 (BTRFS_BLOCK_GROUP_RAID10 |
2570 BTRFS_BLOCK_GROUP_RAID1_MASK |
2571 BTRFS_BLOCK_GROUP_RAID56_MASK |
2572 BTRFS_BLOCK_GROUP_DUP)))
2573 continue;
2574 /*
2575 * Avoid allocating from un-mirrored block group if there are
2576 * mirrored block groups.
2577 */
2578 list_for_each_entry(cache,
2579 &space_info->block_groups[BTRFS_RAID_RAID0],
2580 list)
2581 inc_block_group_ro(cache, 1);
2582 list_for_each_entry(cache,
2583 &space_info->block_groups[BTRFS_RAID_SINGLE],
2584 list)
2585 inc_block_group_ro(cache, 1);
2586 }
2587
2588 btrfs_init_global_block_rsv(info);
2589 ret = check_chunk_block_group_mappings(info);
2590 error:
2591 btrfs_free_path(path);
2592 /*
2593 * We've hit some error while reading the extent tree, and have
2594 * rescue=ibadroots mount option.
2595 * Try to fill the tree using dummy block groups so that the user can
2596 * continue to mount and grab their data.
2597 */
2598 if (ret && btrfs_test_opt(info, IGNOREBADROOTS))
2599 ret = fill_dummy_bgs(info);
2600 return ret;
2601 }
2602
2603 /*
2604 * This function, insert_block_group_item(), belongs to the phase 2 of chunk
2605 * allocation.
2606 *
2607 * See the comment at btrfs_chunk_alloc() for details about the chunk allocation
2608 * phases.
2609 */
2610 static int insert_block_group_item(struct btrfs_trans_handle *trans,
2611 struct btrfs_block_group *block_group)
2612 {
2613 struct btrfs_fs_info *fs_info = trans->fs_info;
2614 struct btrfs_block_group_item bgi;
2615 struct btrfs_root *root = btrfs_block_group_root(fs_info);
2616 struct btrfs_key key;
2617 u64 old_commit_used;
2618 int ret;
2619
2620 spin_lock(&block_group->lock);
2621 btrfs_set_stack_block_group_used(&bgi, block_group->used);
2622 btrfs_set_stack_block_group_chunk_objectid(&bgi,
2623 block_group->global_root_id);
2624 btrfs_set_stack_block_group_flags(&bgi, block_group->flags);
2625 old_commit_used = block_group->commit_used;
2626 block_group->commit_used = block_group->used;
2627 key.objectid = block_group->start;
2628 key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
2629 key.offset = block_group->length;
2630 spin_unlock(&block_group->lock);
2631
2632 ret = btrfs_insert_item(trans, root, &key, &bgi, sizeof(bgi));
2633 if (ret < 0) {
2634 spin_lock(&block_group->lock);
2635 block_group->commit_used = old_commit_used;
2636 spin_unlock(&block_group->lock);
2637 }
2638
2639 return ret;
2640 }
2641
2642 static int insert_dev_extent(struct btrfs_trans_handle *trans,
2643 struct btrfs_device *device, u64 chunk_offset,
2644 u64 start, u64 num_bytes)
2645 {
2646 struct btrfs_fs_info *fs_info = device->fs_info;
2647 struct btrfs_root *root = fs_info->dev_root;
2648 struct btrfs_path *path;
2649 struct btrfs_dev_extent *extent;
2650 struct extent_buffer *leaf;
2651 struct btrfs_key key;
2652 int ret;
2653
2654 WARN_ON(!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state));
2655 WARN_ON(test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state));
2656 path = btrfs_alloc_path();
2657 if (!path)
2658 return -ENOMEM;
2659
2660 key.objectid = device->devid;
2661 key.type = BTRFS_DEV_EXTENT_KEY;
2662 key.offset = start;
2663 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*extent));
2664 if (ret)
2665 goto out;
2666
2667 leaf = path->nodes[0];
2668 extent = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_extent);
2669 btrfs_set_dev_extent_chunk_tree(leaf, extent, BTRFS_CHUNK_TREE_OBJECTID);
2670 btrfs_set_dev_extent_chunk_objectid(leaf, extent,
2671 BTRFS_FIRST_CHUNK_TREE_OBJECTID);
2672 btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
2673
2674 btrfs_set_dev_extent_length(leaf, extent, num_bytes);
2675 btrfs_mark_buffer_dirty(trans, leaf);
2676 out:
2677 btrfs_free_path(path);
2678 return ret;
2679 }
2680
2681 /*
2682 * This function belongs to phase 2.
2683 *
2684 * See the comment at btrfs_chunk_alloc() for details about the chunk allocation
2685 * phases.
2686 */
2687 static int insert_dev_extents(struct btrfs_trans_handle *trans,
2688 u64 chunk_offset, u64 chunk_size)
2689 {
2690 struct btrfs_fs_info *fs_info = trans->fs_info;
2691 struct btrfs_device *device;
2692 struct btrfs_chunk_map *map;
2693 u64 dev_offset;
2694 int i;
2695 int ret = 0;
2696
2697 map = btrfs_get_chunk_map(fs_info, chunk_offset, chunk_size);
2698 if (IS_ERR(map))
2699 return PTR_ERR(map);
2700
2701 /*
2702 * Take the device list mutex to prevent races with the final phase of
2703 * a device replace operation that replaces the device object associated
2704 * with the map's stripes, because the device object's id can change
2705 * at any time during that final phase of the device replace operation
2706 * (dev-replace.c:btrfs_dev_replace_finishing()), so we could grab the
2707 * replaced device and then see it with an ID of BTRFS_DEV_REPLACE_DEVID,
2708 * resulting in persisting a device extent item with such ID.
2709 */
2710 mutex_lock(&fs_info->fs_devices->device_list_mutex);
2711 for (i = 0; i < map->num_stripes; i++) {
2712 device = map->stripes[i].dev;
2713 dev_offset = map->stripes[i].physical;
2714
2715 ret = insert_dev_extent(trans, device, chunk_offset, dev_offset,
2716 map->stripe_size);
2717 if (ret)
2718 break;
2719 }
2720 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2721
2722 btrfs_free_chunk_map(map);
2723 return ret;
2724 }
2725
2726 /*
2727 * This function, btrfs_create_pending_block_groups(), belongs to the phase 2 of
2728 * chunk allocation.
2729 *
2730 * See the comment at btrfs_chunk_alloc() for details about the chunk allocation
2731 * phases.
2732 */
2733 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans)
2734 {
2735 struct btrfs_fs_info *fs_info = trans->fs_info;
2736 struct btrfs_block_group *block_group;
2737 int ret = 0;
2738
2739 while (!list_empty(&trans->new_bgs)) {
2740 int index;
2741
2742 block_group = list_first_entry(&trans->new_bgs,
2743 struct btrfs_block_group,
2744 bg_list);
2745 if (ret)
2746 goto next;
2747
2748 index = btrfs_bg_flags_to_raid_index(block_group->flags);
2749
2750 ret = insert_block_group_item(trans, block_group);
2751 if (ret)
2752 btrfs_abort_transaction(trans, ret);
2753 if (!test_bit(BLOCK_GROUP_FLAG_CHUNK_ITEM_INSERTED,
2754 &block_group->runtime_flags)) {
2755 mutex_lock(&fs_info->chunk_mutex);
2756 ret = btrfs_chunk_alloc_add_chunk_item(trans, block_group);
2757 mutex_unlock(&fs_info->chunk_mutex);
2758 if (ret)
2759 btrfs_abort_transaction(trans, ret);
2760 }
2761 ret = insert_dev_extents(trans, block_group->start,
2762 block_group->length);
2763 if (ret)
2764 btrfs_abort_transaction(trans, ret);
2765 add_block_group_free_space(trans, block_group);
2766
2767 /*
2768 * If we restriped during balance, we may have added a new raid
2769 * type, so now add the sysfs entries when it is safe to do so.
2770 * We don't have to worry about locking here as it's handled in
2771 * btrfs_sysfs_add_block_group_type.
2772 */
2773 if (block_group->space_info->block_group_kobjs[index] == NULL)
2774 btrfs_sysfs_add_block_group_type(block_group);
2775
2776 /* Already aborted the transaction if it failed. */
2777 next:
2778 btrfs_dec_delayed_refs_rsv_bg_inserts(fs_info);
2779 list_del_init(&block_group->bg_list);
2780 clear_bit(BLOCK_GROUP_FLAG_NEW, &block_group->runtime_flags);
2781
2782 /*
2783 * If the block group is still unused, add it to the list of
2784 * unused block groups. The block group may have been created in
2785 * order to satisfy a space reservation, in which case the
2786 * extent allocation only happens later. But often we don't
2787 * actually need to allocate space that we previously reserved,
2788 * so the block group may become unused for a long time. For
2789 * example for metadata we generally reserve space for a worst
2790 * possible scenario, but then don't end up allocating all that
2791 * space or none at all (due to no need to COW, extent buffers
2792 * were already COWed in the current transaction and still
2793 * unwritten, tree heights lower than the maximum possible
2794 * height, etc). For data we generally reserve the axact amount
2795 * of space we are going to allocate later, the exception is
2796 * when using compression, as we must reserve space based on the
2797 * uncompressed data size, because the compression is only done
2798 * when writeback triggered and we don't know how much space we
2799 * are actually going to need, so we reserve the uncompressed
2800 * size because the data may be uncompressible in the worst case.
2801 */
2802 if (ret == 0) {
2803 bool used;
2804
2805 spin_lock(&block_group->lock);
2806 used = btrfs_is_block_group_used(block_group);
2807 spin_unlock(&block_group->lock);
2808
2809 if (!used)
2810 btrfs_mark_bg_unused(block_group);
2811 }
2812 }
2813 btrfs_trans_release_chunk_metadata(trans);
2814 }
2815
2816 /*
2817 * For extent tree v2 we use the block_group_item->chunk_offset to point at our
2818 * global root id. For v1 it's always set to BTRFS_FIRST_CHUNK_TREE_OBJECTID.
2819 */
2820 static u64 calculate_global_root_id(struct btrfs_fs_info *fs_info, u64 offset)
2821 {
2822 u64 div = SZ_1G;
2823 u64 index;
2824
2825 if (!btrfs_fs_incompat(fs_info, EXTENT_TREE_V2))
2826 return BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2827
2828 /* If we have a smaller fs index based on 128MiB. */
2829 if (btrfs_super_total_bytes(fs_info->super_copy) <= (SZ_1G * 10ULL))
2830 div = SZ_128M;
2831
2832 offset = div64_u64(offset, div);
2833 div64_u64_rem(offset, fs_info->nr_global_roots, &index);
2834 return index;
2835 }
2836
2837 struct btrfs_block_group *btrfs_make_block_group(struct btrfs_trans_handle *trans,
2838 u64 type,
2839 u64 chunk_offset, u64 size)
2840 {
2841 struct btrfs_fs_info *fs_info = trans->fs_info;
2842 struct btrfs_block_group *cache;
2843 int ret;
2844
2845 btrfs_set_log_full_commit(trans);
2846
2847 cache = btrfs_create_block_group_cache(fs_info, chunk_offset);
2848 if (!cache)
2849 return ERR_PTR(-ENOMEM);
2850
2851 /*
2852 * Mark it as new before adding it to the rbtree of block groups or any
2853 * list, so that no other task finds it and calls btrfs_mark_bg_unused()
2854 * before the new flag is set.
2855 */
2856 set_bit(BLOCK_GROUP_FLAG_NEW, &cache->runtime_flags);
2857
2858 cache->length = size;
2859 set_free_space_tree_thresholds(cache);
2860 cache->flags = type;
2861 cache->cached = BTRFS_CACHE_FINISHED;
2862 cache->global_root_id = calculate_global_root_id(fs_info, cache->start);
2863
2864 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
2865 set_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &cache->runtime_flags);
2866
2867 ret = btrfs_load_block_group_zone_info(cache, true);
2868 if (ret) {
2869 btrfs_put_block_group(cache);
2870 return ERR_PTR(ret);
2871 }
2872
2873 ret = exclude_super_stripes(cache);
2874 if (ret) {
2875 /* We may have excluded something, so call this just in case */
2876 btrfs_free_excluded_extents(cache);
2877 btrfs_put_block_group(cache);
2878 return ERR_PTR(ret);
2879 }
2880
2881 ret = btrfs_add_new_free_space(cache, chunk_offset, chunk_offset + size, NULL);
2882 btrfs_free_excluded_extents(cache);
2883 if (ret) {
2884 btrfs_put_block_group(cache);
2885 return ERR_PTR(ret);
2886 }
2887
2888 /*
2889 * Ensure the corresponding space_info object is created and
2890 * assigned to our block group. We want our bg to be added to the rbtree
2891 * with its ->space_info set.
2892 */
2893 cache->space_info = btrfs_find_space_info(fs_info, cache->flags);
2894 ASSERT(cache->space_info);
2895
2896 ret = btrfs_add_block_group_cache(fs_info, cache);
2897 if (ret) {
2898 btrfs_remove_free_space_cache(cache);
2899 btrfs_put_block_group(cache);
2900 return ERR_PTR(ret);
2901 }
2902
2903 /*
2904 * Now that our block group has its ->space_info set and is inserted in
2905 * the rbtree, update the space info's counters.
2906 */
2907 trace_btrfs_add_block_group(fs_info, cache, 1);
2908 btrfs_add_bg_to_space_info(fs_info, cache);
2909 btrfs_update_global_block_rsv(fs_info);
2910
2911 #ifdef CONFIG_BTRFS_DEBUG
2912 if (btrfs_should_fragment_free_space(cache)) {
2913 cache->space_info->bytes_used += size >> 1;
2914 fragment_free_space(cache);
2915 }
2916 #endif
2917
2918 list_add_tail(&cache->bg_list, &trans->new_bgs);
2919 btrfs_inc_delayed_refs_rsv_bg_inserts(fs_info);
2920
2921 set_avail_alloc_bits(fs_info, type);
2922 return cache;
2923 }
2924
2925 /*
2926 * Mark one block group RO, can be called several times for the same block
2927 * group.
2928 *
2929 * @cache: the destination block group
2930 * @do_chunk_alloc: whether need to do chunk pre-allocation, this is to
2931 * ensure we still have some free space after marking this
2932 * block group RO.
2933 */
2934 int btrfs_inc_block_group_ro(struct btrfs_block_group *cache,
2935 bool do_chunk_alloc)
2936 {
2937 struct btrfs_fs_info *fs_info = cache->fs_info;
2938 struct btrfs_trans_handle *trans;
2939 struct btrfs_root *root = btrfs_block_group_root(fs_info);
2940 u64 alloc_flags;
2941 int ret;
2942 bool dirty_bg_running;
2943
2944 /*
2945 * This can only happen when we are doing read-only scrub on read-only
2946 * mount.
2947 * In that case we should not start a new transaction on read-only fs.
2948 * Thus here we skip all chunk allocations.
2949 */
2950 if (sb_rdonly(fs_info->sb)) {
2951 mutex_lock(&fs_info->ro_block_group_mutex);
2952 ret = inc_block_group_ro(cache, 0);
2953 mutex_unlock(&fs_info->ro_block_group_mutex);
2954 return ret;
2955 }
2956
2957 do {
2958 trans = btrfs_join_transaction(root);
2959 if (IS_ERR(trans))
2960 return PTR_ERR(trans);
2961
2962 dirty_bg_running = false;
2963
2964 /*
2965 * We're not allowed to set block groups readonly after the dirty
2966 * block group cache has started writing. If it already started,
2967 * back off and let this transaction commit.
2968 */
2969 mutex_lock(&fs_info->ro_block_group_mutex);
2970 if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
2971 u64 transid = trans->transid;
2972
2973 mutex_unlock(&fs_info->ro_block_group_mutex);
2974 btrfs_end_transaction(trans);
2975
2976 ret = btrfs_wait_for_commit(fs_info, transid);
2977 if (ret)
2978 return ret;
2979 dirty_bg_running = true;
2980 }
2981 } while (dirty_bg_running);
2982
2983 if (do_chunk_alloc) {
2984 /*
2985 * If we are changing raid levels, try to allocate a
2986 * corresponding block group with the new raid level.
2987 */
2988 alloc_flags = btrfs_get_alloc_profile(fs_info, cache->flags);
2989 if (alloc_flags != cache->flags) {
2990 ret = btrfs_chunk_alloc(trans, alloc_flags,
2991 CHUNK_ALLOC_FORCE);
2992 /*
2993 * ENOSPC is allowed here, we may have enough space
2994 * already allocated at the new raid level to carry on
2995 */
2996 if (ret == -ENOSPC)
2997 ret = 0;
2998 if (ret < 0)
2999 goto out;
3000 }
3001 }
3002
3003 ret = inc_block_group_ro(cache, 0);
3004 if (!ret)
3005 goto out;
3006 if (ret == -ETXTBSY)
3007 goto unlock_out;
3008
3009 /*
3010 * Skip chunk allocation if the bg is SYSTEM, this is to avoid system
3011 * chunk allocation storm to exhaust the system chunk array. Otherwise
3012 * we still want to try our best to mark the block group read-only.
3013 */
3014 if (!do_chunk_alloc && ret == -ENOSPC &&
3015 (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM))
3016 goto unlock_out;
3017
3018 alloc_flags = btrfs_get_alloc_profile(fs_info, cache->space_info->flags);
3019 ret = btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
3020 if (ret < 0)
3021 goto out;
3022 /*
3023 * We have allocated a new chunk. We also need to activate that chunk to
3024 * grant metadata tickets for zoned filesystem.
3025 */
3026 ret = btrfs_zoned_activate_one_bg(fs_info, cache->space_info, true);
3027 if (ret < 0)
3028 goto out;
3029
3030 ret = inc_block_group_ro(cache, 0);
3031 if (ret == -ETXTBSY)
3032 goto unlock_out;
3033 out:
3034 if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
3035 alloc_flags = btrfs_get_alloc_profile(fs_info, cache->flags);
3036 mutex_lock(&fs_info->chunk_mutex);
3037 check_system_chunk(trans, alloc_flags);
3038 mutex_unlock(&fs_info->chunk_mutex);
3039 }
3040 unlock_out:
3041 mutex_unlock(&fs_info->ro_block_group_mutex);
3042
3043 btrfs_end_transaction(trans);
3044 return ret;
3045 }
3046
3047 void btrfs_dec_block_group_ro(struct btrfs_block_group *cache)
3048 {
3049 struct btrfs_space_info *sinfo = cache->space_info;
3050 u64 num_bytes;
3051
3052 BUG_ON(!cache->ro);
3053
3054 spin_lock(&sinfo->lock);
3055 spin_lock(&cache->lock);
3056 if (!--cache->ro) {
3057 if (btrfs_is_zoned(cache->fs_info)) {
3058 /* Migrate zone_unusable bytes back */
3059 cache->zone_unusable =
3060 (cache->alloc_offset - cache->used - cache->pinned -
3061 cache->reserved) +
3062 (cache->length - cache->zone_capacity);
3063 btrfs_space_info_update_bytes_zone_unusable(cache->fs_info, sinfo,
3064 cache->zone_unusable);
3065 sinfo->bytes_readonly -= cache->zone_unusable;
3066 }
3067 num_bytes = cache->length - cache->reserved -
3068 cache->pinned - cache->bytes_super -
3069 cache->zone_unusable - cache->used;
3070 sinfo->bytes_readonly -= num_bytes;
3071 list_del_init(&cache->ro_list);
3072 }
3073 spin_unlock(&cache->lock);
3074 spin_unlock(&sinfo->lock);
3075 }
3076
3077 static int update_block_group_item(struct btrfs_trans_handle *trans,
3078 struct btrfs_path *path,
3079 struct btrfs_block_group *cache)
3080 {
3081 struct btrfs_fs_info *fs_info = trans->fs_info;
3082 int ret;
3083 struct btrfs_root *root = btrfs_block_group_root(fs_info);
3084 unsigned long bi;
3085 struct extent_buffer *leaf;
3086 struct btrfs_block_group_item bgi;
3087 struct btrfs_key key;
3088 u64 old_commit_used;
3089 u64 used;
3090
3091 /*
3092 * Block group items update can be triggered out of commit transaction
3093 * critical section, thus we need a consistent view of used bytes.
3094 * We cannot use cache->used directly outside of the spin lock, as it
3095 * may be changed.
3096 */
3097 spin_lock(&cache->lock);
3098 old_commit_used = cache->commit_used;
3099 used = cache->used;
3100 /* No change in used bytes, can safely skip it. */
3101 if (cache->commit_used == used) {
3102 spin_unlock(&cache->lock);
3103 return 0;
3104 }
3105 cache->commit_used = used;
3106 spin_unlock(&cache->lock);
3107
3108 key.objectid = cache->start;
3109 key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
3110 key.offset = cache->length;
3111
3112 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
3113 if (ret) {
3114 if (ret > 0)
3115 ret = -ENOENT;
3116 goto fail;
3117 }
3118
3119 leaf = path->nodes[0];
3120 bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3121 btrfs_set_stack_block_group_used(&bgi, used);
3122 btrfs_set_stack_block_group_chunk_objectid(&bgi,
3123 cache->global_root_id);
3124 btrfs_set_stack_block_group_flags(&bgi, cache->flags);
3125 write_extent_buffer(leaf, &bgi, bi, sizeof(bgi));
3126 btrfs_mark_buffer_dirty(trans, leaf);
3127 fail:
3128 btrfs_release_path(path);
3129 /*
3130 * We didn't update the block group item, need to revert commit_used
3131 * unless the block group item didn't exist yet - this is to prevent a
3132 * race with a concurrent insertion of the block group item, with
3133 * insert_block_group_item(), that happened just after we attempted to
3134 * update. In that case we would reset commit_used to 0 just after the
3135 * insertion set it to a value greater than 0 - if the block group later
3136 * becomes with 0 used bytes, we would incorrectly skip its update.
3137 */
3138 if (ret < 0 && ret != -ENOENT) {
3139 spin_lock(&cache->lock);
3140 cache->commit_used = old_commit_used;
3141 spin_unlock(&cache->lock);
3142 }
3143 return ret;
3144
3145 }
3146
3147 static int cache_save_setup(struct btrfs_block_group *block_group,
3148 struct btrfs_trans_handle *trans,
3149 struct btrfs_path *path)
3150 {
3151 struct btrfs_fs_info *fs_info = block_group->fs_info;
3152 struct inode *inode = NULL;
3153 struct extent_changeset *data_reserved = NULL;
3154 u64 alloc_hint = 0;
3155 int dcs = BTRFS_DC_ERROR;
3156 u64 cache_size = 0;
3157 int retries = 0;
3158 int ret = 0;
3159
3160 if (!btrfs_test_opt(fs_info, SPACE_CACHE))
3161 return 0;
3162
3163 /*
3164 * If this block group is smaller than 100 megs don't bother caching the
3165 * block group.
3166 */
3167 if (block_group->length < (100 * SZ_1M)) {
3168 spin_lock(&block_group->lock);
3169 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3170 spin_unlock(&block_group->lock);
3171 return 0;
3172 }
3173
3174 if (TRANS_ABORTED(trans))
3175 return 0;
3176 again:
3177 inode = lookup_free_space_inode(block_group, path);
3178 if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3179 ret = PTR_ERR(inode);
3180 btrfs_release_path(path);
3181 goto out;
3182 }
3183
3184 if (IS_ERR(inode)) {
3185 BUG_ON(retries);
3186 retries++;
3187
3188 if (block_group->ro)
3189 goto out_free;
3190
3191 ret = create_free_space_inode(trans, block_group, path);
3192 if (ret)
3193 goto out_free;
3194 goto again;
3195 }
3196
3197 /*
3198 * We want to set the generation to 0, that way if anything goes wrong
3199 * from here on out we know not to trust this cache when we load up next
3200 * time.
3201 */
3202 BTRFS_I(inode)->generation = 0;
3203 ret = btrfs_update_inode(trans, BTRFS_I(inode));
3204 if (ret) {
3205 /*
3206 * So theoretically we could recover from this, simply set the
3207 * super cache generation to 0 so we know to invalidate the
3208 * cache, but then we'd have to keep track of the block groups
3209 * that fail this way so we know we _have_ to reset this cache
3210 * before the next commit or risk reading stale cache. So to
3211 * limit our exposure to horrible edge cases lets just abort the
3212 * transaction, this only happens in really bad situations
3213 * anyway.
3214 */
3215 btrfs_abort_transaction(trans, ret);
3216 goto out_put;
3217 }
3218 WARN_ON(ret);
3219
3220 /* We've already setup this transaction, go ahead and exit */
3221 if (block_group->cache_generation == trans->transid &&
3222 i_size_read(inode)) {
3223 dcs = BTRFS_DC_SETUP;
3224 goto out_put;
3225 }
3226
3227 if (i_size_read(inode) > 0) {
3228 ret = btrfs_check_trunc_cache_free_space(fs_info,
3229 &fs_info->global_block_rsv);
3230 if (ret)
3231 goto out_put;
3232
3233 ret = btrfs_truncate_free_space_cache(trans, NULL, inode);
3234 if (ret)
3235 goto out_put;
3236 }
3237
3238 spin_lock(&block_group->lock);
3239 if (block_group->cached != BTRFS_CACHE_FINISHED ||
3240 !btrfs_test_opt(fs_info, SPACE_CACHE)) {
3241 /*
3242 * don't bother trying to write stuff out _if_
3243 * a) we're not cached,
3244 * b) we're with nospace_cache mount option,
3245 * c) we're with v2 space_cache (FREE_SPACE_TREE).
3246 */
3247 dcs = BTRFS_DC_WRITTEN;
3248 spin_unlock(&block_group->lock);
3249 goto out_put;
3250 }
3251 spin_unlock(&block_group->lock);
3252
3253 /*
3254 * We hit an ENOSPC when setting up the cache in this transaction, just
3255 * skip doing the setup, we've already cleared the cache so we're safe.
3256 */
3257 if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
3258 ret = -ENOSPC;
3259 goto out_put;
3260 }
3261
3262 /*
3263 * Try to preallocate enough space based on how big the block group is.
3264 * Keep in mind this has to include any pinned space which could end up
3265 * taking up quite a bit since it's not folded into the other space
3266 * cache.
3267 */
3268 cache_size = div_u64(block_group->length, SZ_256M);
3269 if (!cache_size)
3270 cache_size = 1;
3271
3272 cache_size *= 16;
3273 cache_size *= fs_info->sectorsize;
3274
3275 ret = btrfs_check_data_free_space(BTRFS_I(inode), &data_reserved, 0,
3276 cache_size, false);
3277 if (ret)
3278 goto out_put;
3279
3280 ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, cache_size,
3281 cache_size, cache_size,
3282 &alloc_hint);
3283 /*
3284 * Our cache requires contiguous chunks so that we don't modify a bunch
3285 * of metadata or split extents when writing the cache out, which means
3286 * we can enospc if we are heavily fragmented in addition to just normal
3287 * out of space conditions. So if we hit this just skip setting up any
3288 * other block groups for this transaction, maybe we'll unpin enough
3289 * space the next time around.
3290 */
3291 if (!ret)
3292 dcs = BTRFS_DC_SETUP;
3293 else if (ret == -ENOSPC)
3294 set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
3295
3296 out_put:
3297 iput(inode);
3298 out_free:
3299 btrfs_release_path(path);
3300 out:
3301 spin_lock(&block_group->lock);
3302 if (!ret && dcs == BTRFS_DC_SETUP)
3303 block_group->cache_generation = trans->transid;
3304 block_group->disk_cache_state = dcs;
3305 spin_unlock(&block_group->lock);
3306
3307 extent_changeset_free(data_reserved);
3308 return ret;
3309 }
3310
3311 int btrfs_setup_space_cache(struct btrfs_trans_handle *trans)
3312 {
3313 struct btrfs_fs_info *fs_info = trans->fs_info;
3314 struct btrfs_block_group *cache, *tmp;
3315 struct btrfs_transaction *cur_trans = trans->transaction;
3316 struct btrfs_path *path;
3317
3318 if (list_empty(&cur_trans->dirty_bgs) ||
3319 !btrfs_test_opt(fs_info, SPACE_CACHE))
3320 return 0;
3321
3322 path = btrfs_alloc_path();
3323 if (!path)
3324 return -ENOMEM;
3325
3326 /* Could add new block groups, use _safe just in case */
3327 list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
3328 dirty_list) {
3329 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3330 cache_save_setup(cache, trans, path);
3331 }
3332
3333 btrfs_free_path(path);
3334 return 0;
3335 }
3336
3337 /*
3338 * Transaction commit does final block group cache writeback during a critical
3339 * section where nothing is allowed to change the FS. This is required in
3340 * order for the cache to actually match the block group, but can introduce a
3341 * lot of latency into the commit.
3342 *
3343 * So, btrfs_start_dirty_block_groups is here to kick off block group cache IO.
3344 * There's a chance we'll have to redo some of it if the block group changes
3345 * again during the commit, but it greatly reduces the commit latency by
3346 * getting rid of the easy block groups while we're still allowing others to
3347 * join the commit.
3348 */
3349 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans)
3350 {
3351 struct btrfs_fs_info *fs_info = trans->fs_info;
3352 struct btrfs_block_group *cache;
3353 struct btrfs_transaction *cur_trans = trans->transaction;
3354 int ret = 0;
3355 int should_put;
3356 struct btrfs_path *path = NULL;
3357 LIST_HEAD(dirty);
3358 struct list_head *io = &cur_trans->io_bgs;
3359 int loops = 0;
3360
3361 spin_lock(&cur_trans->dirty_bgs_lock);
3362 if (list_empty(&cur_trans->dirty_bgs)) {
3363 spin_unlock(&cur_trans->dirty_bgs_lock);
3364 return 0;
3365 }
3366 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3367 spin_unlock(&cur_trans->dirty_bgs_lock);
3368
3369 again:
3370 /* Make sure all the block groups on our dirty list actually exist */
3371 btrfs_create_pending_block_groups(trans);
3372
3373 if (!path) {
3374 path = btrfs_alloc_path();
3375 if (!path) {
3376 ret = -ENOMEM;
3377 goto out;
3378 }
3379 }
3380
3381 /*
3382 * cache_write_mutex is here only to save us from balance or automatic
3383 * removal of empty block groups deleting this block group while we are
3384 * writing out the cache
3385 */
3386 mutex_lock(&trans->transaction->cache_write_mutex);
3387 while (!list_empty(&dirty)) {
3388 bool drop_reserve = true;
3389
3390 cache = list_first_entry(&dirty, struct btrfs_block_group,
3391 dirty_list);
3392 /*
3393 * This can happen if something re-dirties a block group that
3394 * is already under IO. Just wait for it to finish and then do
3395 * it all again
3396 */
3397 if (!list_empty(&cache->io_list)) {
3398 list_del_init(&cache->io_list);
3399 btrfs_wait_cache_io(trans, cache, path);
3400 btrfs_put_block_group(cache);
3401 }
3402
3403
3404 /*
3405 * btrfs_wait_cache_io uses the cache->dirty_list to decide if
3406 * it should update the cache_state. Don't delete until after
3407 * we wait.
3408 *
3409 * Since we're not running in the commit critical section
3410 * we need the dirty_bgs_lock to protect from update_block_group
3411 */
3412 spin_lock(&cur_trans->dirty_bgs_lock);
3413 list_del_init(&cache->dirty_list);
3414 spin_unlock(&cur_trans->dirty_bgs_lock);
3415
3416 should_put = 1;
3417
3418 cache_save_setup(cache, trans, path);
3419
3420 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
3421 cache->io_ctl.inode = NULL;
3422 ret = btrfs_write_out_cache(trans, cache, path);
3423 if (ret == 0 && cache->io_ctl.inode) {
3424 should_put = 0;
3425
3426 /*
3427 * The cache_write_mutex is protecting the
3428 * io_list, also refer to the definition of
3429 * btrfs_transaction::io_bgs for more details
3430 */
3431 list_add_tail(&cache->io_list, io);
3432 } else {
3433 /*
3434 * If we failed to write the cache, the
3435 * generation will be bad and life goes on
3436 */
3437 ret = 0;
3438 }
3439 }
3440 if (!ret) {
3441 ret = update_block_group_item(trans, path, cache);
3442 /*
3443 * Our block group might still be attached to the list
3444 * of new block groups in the transaction handle of some
3445 * other task (struct btrfs_trans_handle->new_bgs). This
3446 * means its block group item isn't yet in the extent
3447 * tree. If this happens ignore the error, as we will
3448 * try again later in the critical section of the
3449 * transaction commit.
3450 */
3451 if (ret == -ENOENT) {
3452 ret = 0;
3453 spin_lock(&cur_trans->dirty_bgs_lock);
3454 if (list_empty(&cache->dirty_list)) {
3455 list_add_tail(&cache->dirty_list,
3456 &cur_trans->dirty_bgs);
3457 btrfs_get_block_group(cache);
3458 drop_reserve = false;
3459 }
3460 spin_unlock(&cur_trans->dirty_bgs_lock);
3461 } else if (ret) {
3462 btrfs_abort_transaction(trans, ret);
3463 }
3464 }
3465
3466 /* If it's not on the io list, we need to put the block group */
3467 if (should_put)
3468 btrfs_put_block_group(cache);
3469 if (drop_reserve)
3470 btrfs_dec_delayed_refs_rsv_bg_updates(fs_info);
3471 /*
3472 * Avoid blocking other tasks for too long. It might even save
3473 * us from writing caches for block groups that are going to be
3474 * removed.
3475 */
3476 mutex_unlock(&trans->transaction->cache_write_mutex);
3477 if (ret)
3478 goto out;
3479 mutex_lock(&trans->transaction->cache_write_mutex);
3480 }
3481 mutex_unlock(&trans->transaction->cache_write_mutex);
3482
3483 /*
3484 * Go through delayed refs for all the stuff we've just kicked off
3485 * and then loop back (just once)
3486 */
3487 if (!ret)
3488 ret = btrfs_run_delayed_refs(trans, 0);
3489 if (!ret && loops == 0) {
3490 loops++;
3491 spin_lock(&cur_trans->dirty_bgs_lock);
3492 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3493 /*
3494 * dirty_bgs_lock protects us from concurrent block group
3495 * deletes too (not just cache_write_mutex).
3496 */
3497 if (!list_empty(&dirty)) {
3498 spin_unlock(&cur_trans->dirty_bgs_lock);
3499 goto again;
3500 }
3501 spin_unlock(&cur_trans->dirty_bgs_lock);
3502 }
3503 out:
3504 if (ret < 0) {
3505 spin_lock(&cur_trans->dirty_bgs_lock);
3506 list_splice_init(&dirty, &cur_trans->dirty_bgs);
3507 spin_unlock(&cur_trans->dirty_bgs_lock);
3508 btrfs_cleanup_dirty_bgs(cur_trans, fs_info);
3509 }
3510
3511 btrfs_free_path(path);
3512 return ret;
3513 }
3514
3515 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans)
3516 {
3517 struct btrfs_fs_info *fs_info = trans->fs_info;
3518 struct btrfs_block_group *cache;
3519 struct btrfs_transaction *cur_trans = trans->transaction;
3520 int ret = 0;
3521 int should_put;
3522 struct btrfs_path *path;
3523 struct list_head *io = &cur_trans->io_bgs;
3524
3525 path = btrfs_alloc_path();
3526 if (!path)
3527 return -ENOMEM;
3528
3529 /*
3530 * Even though we are in the critical section of the transaction commit,
3531 * we can still have concurrent tasks adding elements to this
3532 * transaction's list of dirty block groups. These tasks correspond to
3533 * endio free space workers started when writeback finishes for a
3534 * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
3535 * allocate new block groups as a result of COWing nodes of the root
3536 * tree when updating the free space inode. The writeback for the space
3537 * caches is triggered by an earlier call to
3538 * btrfs_start_dirty_block_groups() and iterations of the following
3539 * loop.
3540 * Also we want to do the cache_save_setup first and then run the
3541 * delayed refs to make sure we have the best chance at doing this all
3542 * in one shot.
3543 */
3544 spin_lock(&cur_trans->dirty_bgs_lock);
3545 while (!list_empty(&cur_trans->dirty_bgs)) {
3546 cache = list_first_entry(&cur_trans->dirty_bgs,
3547 struct btrfs_block_group,
3548 dirty_list);
3549
3550 /*
3551 * This can happen if cache_save_setup re-dirties a block group
3552 * that is already under IO. Just wait for it to finish and
3553 * then do it all again
3554 */
3555 if (!list_empty(&cache->io_list)) {
3556 spin_unlock(&cur_trans->dirty_bgs_lock);
3557 list_del_init(&cache->io_list);
3558 btrfs_wait_cache_io(trans, cache, path);
3559 btrfs_put_block_group(cache);
3560 spin_lock(&cur_trans->dirty_bgs_lock);
3561 }
3562
3563 /*
3564 * Don't remove from the dirty list until after we've waited on
3565 * any pending IO
3566 */
3567 list_del_init(&cache->dirty_list);
3568 spin_unlock(&cur_trans->dirty_bgs_lock);
3569 should_put = 1;
3570
3571 cache_save_setup(cache, trans, path);
3572
3573 if (!ret)
3574 ret = btrfs_run_delayed_refs(trans, U64_MAX);
3575
3576 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
3577 cache->io_ctl.inode = NULL;
3578 ret = btrfs_write_out_cache(trans, cache, path);
3579 if (ret == 0 && cache->io_ctl.inode) {
3580 should_put = 0;
3581 list_add_tail(&cache->io_list, io);
3582 } else {
3583 /*
3584 * If we failed to write the cache, the
3585 * generation will be bad and life goes on
3586 */
3587 ret = 0;
3588 }
3589 }
3590 if (!ret) {
3591 ret = update_block_group_item(trans, path, cache);
3592 /*
3593 * One of the free space endio workers might have
3594 * created a new block group while updating a free space
3595 * cache's inode (at inode.c:btrfs_finish_ordered_io())
3596 * and hasn't released its transaction handle yet, in
3597 * which case the new block group is still attached to
3598 * its transaction handle and its creation has not
3599 * finished yet (no block group item in the extent tree
3600 * yet, etc). If this is the case, wait for all free
3601 * space endio workers to finish and retry. This is a
3602 * very rare case so no need for a more efficient and
3603 * complex approach.
3604 */
3605 if (ret == -ENOENT) {
3606 wait_event(cur_trans->writer_wait,
3607 atomic_read(&cur_trans->num_writers) == 1);
3608 ret = update_block_group_item(trans, path, cache);
3609 }
3610 if (ret)
3611 btrfs_abort_transaction(trans, ret);
3612 }
3613
3614 /* If its not on the io list, we need to put the block group */
3615 if (should_put)
3616 btrfs_put_block_group(cache);
3617 btrfs_dec_delayed_refs_rsv_bg_updates(fs_info);
3618 spin_lock(&cur_trans->dirty_bgs_lock);
3619 }
3620 spin_unlock(&cur_trans->dirty_bgs_lock);
3621
3622 /*
3623 * Refer to the definition of io_bgs member for details why it's safe
3624 * to use it without any locking
3625 */
3626 while (!list_empty(io)) {
3627 cache = list_first_entry(io, struct btrfs_block_group,
3628 io_list);
3629 list_del_init(&cache->io_list);
3630 btrfs_wait_cache_io(trans, cache, path);
3631 btrfs_put_block_group(cache);
3632 }
3633
3634 btrfs_free_path(path);
3635 return ret;
3636 }
3637
3638 int btrfs_update_block_group(struct btrfs_trans_handle *trans,
3639 u64 bytenr, u64 num_bytes, bool alloc)
3640 {
3641 struct btrfs_fs_info *info = trans->fs_info;
3642 struct btrfs_space_info *space_info;
3643 struct btrfs_block_group *cache;
3644 u64 old_val;
3645 bool reclaim = false;
3646 bool bg_already_dirty = true;
3647 int factor;
3648
3649 /* Block accounting for super block */
3650 spin_lock(&info->delalloc_root_lock);
3651 old_val = btrfs_super_bytes_used(info->super_copy);
3652 if (alloc)
3653 old_val += num_bytes;
3654 else
3655 old_val -= num_bytes;
3656 btrfs_set_super_bytes_used(info->super_copy, old_val);
3657 spin_unlock(&info->delalloc_root_lock);
3658
3659 cache = btrfs_lookup_block_group(info, bytenr);
3660 if (!cache)
3661 return -ENOENT;
3662
3663 /* An extent can not span multiple block groups. */
3664 ASSERT(bytenr + num_bytes <= cache->start + cache->length);
3665
3666 space_info = cache->space_info;
3667 factor = btrfs_bg_type_to_factor(cache->flags);
3668
3669 /*
3670 * If this block group has free space cache written out, we need to make
3671 * sure to load it if we are removing space. This is because we need
3672 * the unpinning stage to actually add the space back to the block group,
3673 * otherwise we will leak space.
3674 */
3675 if (!alloc && !btrfs_block_group_done(cache))
3676 btrfs_cache_block_group(cache, true);
3677
3678 spin_lock(&space_info->lock);
3679 spin_lock(&cache->lock);
3680
3681 if (btrfs_test_opt(info, SPACE_CACHE) &&
3682 cache->disk_cache_state < BTRFS_DC_CLEAR)
3683 cache->disk_cache_state = BTRFS_DC_CLEAR;
3684
3685 old_val = cache->used;
3686 if (alloc) {
3687 old_val += num_bytes;
3688 cache->used = old_val;
3689 cache->reserved -= num_bytes;
3690 cache->reclaim_mark = 0;
3691 space_info->bytes_reserved -= num_bytes;
3692 space_info->bytes_used += num_bytes;
3693 space_info->disk_used += num_bytes * factor;
3694 if (READ_ONCE(space_info->periodic_reclaim))
3695 btrfs_space_info_update_reclaimable(space_info, -num_bytes);
3696 spin_unlock(&cache->lock);
3697 spin_unlock(&space_info->lock);
3698 } else {
3699 old_val -= num_bytes;
3700 cache->used = old_val;
3701 cache->pinned += num_bytes;
3702 btrfs_space_info_update_bytes_pinned(info, space_info, num_bytes);
3703 space_info->bytes_used -= num_bytes;
3704 space_info->disk_used -= num_bytes * factor;
3705 if (READ_ONCE(space_info->periodic_reclaim))
3706 btrfs_space_info_update_reclaimable(space_info, num_bytes);
3707 else
3708 reclaim = should_reclaim_block_group(cache, num_bytes);
3709
3710 spin_unlock(&cache->lock);
3711 spin_unlock(&space_info->lock);
3712
3713 set_extent_bit(&trans->transaction->pinned_extents, bytenr,
3714 bytenr + num_bytes - 1, EXTENT_DIRTY, NULL);
3715 }
3716
3717 spin_lock(&trans->transaction->dirty_bgs_lock);
3718 if (list_empty(&cache->dirty_list)) {
3719 list_add_tail(&cache->dirty_list, &trans->transaction->dirty_bgs);
3720 bg_already_dirty = false;
3721 btrfs_get_block_group(cache);
3722 }
3723 spin_unlock(&trans->transaction->dirty_bgs_lock);
3724
3725 /*
3726 * No longer have used bytes in this block group, queue it for deletion.
3727 * We do this after adding the block group to the dirty list to avoid
3728 * races between cleaner kthread and space cache writeout.
3729 */
3730 if (!alloc && old_val == 0) {
3731 if (!btrfs_test_opt(info, DISCARD_ASYNC))
3732 btrfs_mark_bg_unused(cache);
3733 } else if (!alloc && reclaim) {
3734 btrfs_mark_bg_to_reclaim(cache);
3735 }
3736
3737 btrfs_put_block_group(cache);
3738
3739 /* Modified block groups are accounted for in the delayed_refs_rsv. */
3740 if (!bg_already_dirty)
3741 btrfs_inc_delayed_refs_rsv_bg_updates(info);
3742
3743 return 0;
3744 }
3745
3746 /*
3747 * Update the block_group and space info counters.
3748 *
3749 * @cache: The cache we are manipulating
3750 * @ram_bytes: The number of bytes of file content, and will be same to
3751 * @num_bytes except for the compress path.
3752 * @num_bytes: The number of bytes in question
3753 * @delalloc: The blocks are allocated for the delalloc write
3754 *
3755 * This is called by the allocator when it reserves space. If this is a
3756 * reservation and the block group has become read only we cannot make the
3757 * reservation and return -EAGAIN, otherwise this function always succeeds.
3758 */
3759 int btrfs_add_reserved_bytes(struct btrfs_block_group *cache,
3760 u64 ram_bytes, u64 num_bytes, int delalloc,
3761 bool force_wrong_size_class)
3762 {
3763 struct btrfs_space_info *space_info = cache->space_info;
3764 enum btrfs_block_group_size_class size_class;
3765 int ret = 0;
3766
3767 spin_lock(&space_info->lock);
3768 spin_lock(&cache->lock);
3769 if (cache->ro) {
3770 ret = -EAGAIN;
3771 goto out;
3772 }
3773
3774 if (btrfs_block_group_should_use_size_class(cache)) {
3775 size_class = btrfs_calc_block_group_size_class(num_bytes);
3776 ret = btrfs_use_block_group_size_class(cache, size_class, force_wrong_size_class);
3777 if (ret)
3778 goto out;
3779 }
3780 cache->reserved += num_bytes;
3781 space_info->bytes_reserved += num_bytes;
3782 trace_btrfs_space_reservation(cache->fs_info, "space_info",
3783 space_info->flags, num_bytes, 1);
3784 btrfs_space_info_update_bytes_may_use(cache->fs_info,
3785 space_info, -ram_bytes);
3786 if (delalloc)
3787 cache->delalloc_bytes += num_bytes;
3788
3789 /*
3790 * Compression can use less space than we reserved, so wake tickets if
3791 * that happens.
3792 */
3793 if (num_bytes < ram_bytes)
3794 btrfs_try_granting_tickets(cache->fs_info, space_info);
3795 out:
3796 spin_unlock(&cache->lock);
3797 spin_unlock(&space_info->lock);
3798 return ret;
3799 }
3800
3801 /*
3802 * Update the block_group and space info counters.
3803 *
3804 * @cache: The cache we are manipulating
3805 * @num_bytes: The number of bytes in question
3806 * @delalloc: The blocks are allocated for the delalloc write
3807 *
3808 * This is called by somebody who is freeing space that was never actually used
3809 * on disk. For example if you reserve some space for a new leaf in transaction
3810 * A and before transaction A commits you free that leaf, you call this with
3811 * reserve set to 0 in order to clear the reservation.
3812 */
3813 void btrfs_free_reserved_bytes(struct btrfs_block_group *cache,
3814 u64 num_bytes, int delalloc)
3815 {
3816 struct btrfs_space_info *space_info = cache->space_info;
3817
3818 spin_lock(&space_info->lock);
3819 spin_lock(&cache->lock);
3820 if (cache->ro)
3821 space_info->bytes_readonly += num_bytes;
3822 cache->reserved -= num_bytes;
3823 space_info->bytes_reserved -= num_bytes;
3824 space_info->max_extent_size = 0;
3825
3826 if (delalloc)
3827 cache->delalloc_bytes -= num_bytes;
3828 spin_unlock(&cache->lock);
3829
3830 btrfs_try_granting_tickets(cache->fs_info, space_info);
3831 spin_unlock(&space_info->lock);
3832 }
3833
3834 static void force_metadata_allocation(struct btrfs_fs_info *info)
3835 {
3836 struct list_head *head = &info->space_info;
3837 struct btrfs_space_info *found;
3838
3839 list_for_each_entry(found, head, list) {
3840 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3841 found->force_alloc = CHUNK_ALLOC_FORCE;
3842 }
3843 }
3844
3845 static int should_alloc_chunk(struct btrfs_fs_info *fs_info,
3846 struct btrfs_space_info *sinfo, int force)
3847 {
3848 u64 bytes_used = btrfs_space_info_used(sinfo, false);
3849 u64 thresh;
3850
3851 if (force == CHUNK_ALLOC_FORCE)
3852 return 1;
3853
3854 /*
3855 * in limited mode, we want to have some free space up to
3856 * about 1% of the FS size.
3857 */
3858 if (force == CHUNK_ALLOC_LIMITED) {
3859 thresh = btrfs_super_total_bytes(fs_info->super_copy);
3860 thresh = max_t(u64, SZ_64M, mult_perc(thresh, 1));
3861
3862 if (sinfo->total_bytes - bytes_used < thresh)
3863 return 1;
3864 }
3865
3866 if (bytes_used + SZ_2M < mult_perc(sinfo->total_bytes, 80))
3867 return 0;
3868 return 1;
3869 }
3870
3871 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans, u64 type)
3872 {
3873 u64 alloc_flags = btrfs_get_alloc_profile(trans->fs_info, type);
3874
3875 return btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
3876 }
3877
3878 static struct btrfs_block_group *do_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags)
3879 {
3880 struct btrfs_block_group *bg;
3881 int ret;
3882
3883 /*
3884 * Check if we have enough space in the system space info because we
3885 * will need to update device items in the chunk btree and insert a new
3886 * chunk item in the chunk btree as well. This will allocate a new
3887 * system block group if needed.
3888 */
3889 check_system_chunk(trans, flags);
3890
3891 bg = btrfs_create_chunk(trans, flags);
3892 if (IS_ERR(bg)) {
3893 ret = PTR_ERR(bg);
3894 goto out;
3895 }
3896
3897 ret = btrfs_chunk_alloc_add_chunk_item(trans, bg);
3898 /*
3899 * Normally we are not expected to fail with -ENOSPC here, since we have
3900 * previously reserved space in the system space_info and allocated one
3901 * new system chunk if necessary. However there are three exceptions:
3902 *
3903 * 1) We may have enough free space in the system space_info but all the
3904 * existing system block groups have a profile which can not be used
3905 * for extent allocation.
3906 *
3907 * This happens when mounting in degraded mode. For example we have a
3908 * RAID1 filesystem with 2 devices, lose one device and mount the fs
3909 * using the other device in degraded mode. If we then allocate a chunk,
3910 * we may have enough free space in the existing system space_info, but
3911 * none of the block groups can be used for extent allocation since they
3912 * have a RAID1 profile, and because we are in degraded mode with a
3913 * single device, we are forced to allocate a new system chunk with a
3914 * SINGLE profile. Making check_system_chunk() iterate over all system
3915 * block groups and check if they have a usable profile and enough space
3916 * can be slow on very large filesystems, so we tolerate the -ENOSPC and
3917 * try again after forcing allocation of a new system chunk. Like this
3918 * we avoid paying the cost of that search in normal circumstances, when
3919 * we were not mounted in degraded mode;
3920 *
3921 * 2) We had enough free space info the system space_info, and one suitable
3922 * block group to allocate from when we called check_system_chunk()
3923 * above. However right after we called it, the only system block group
3924 * with enough free space got turned into RO mode by a running scrub,
3925 * and in this case we have to allocate a new one and retry. We only
3926 * need do this allocate and retry once, since we have a transaction
3927 * handle and scrub uses the commit root to search for block groups;
3928 *
3929 * 3) We had one system block group with enough free space when we called
3930 * check_system_chunk(), but after that, right before we tried to
3931 * allocate the last extent buffer we needed, a discard operation came
3932 * in and it temporarily removed the last free space entry from the
3933 * block group (discard removes a free space entry, discards it, and
3934 * then adds back the entry to the block group cache).
3935 */
3936 if (ret == -ENOSPC) {
3937 const u64 sys_flags = btrfs_system_alloc_profile(trans->fs_info);
3938 struct btrfs_block_group *sys_bg;
3939
3940 sys_bg = btrfs_create_chunk(trans, sys_flags);
3941 if (IS_ERR(sys_bg)) {
3942 ret = PTR_ERR(sys_bg);
3943 btrfs_abort_transaction(trans, ret);
3944 goto out;
3945 }
3946
3947 ret = btrfs_chunk_alloc_add_chunk_item(trans, sys_bg);
3948 if (ret) {
3949 btrfs_abort_transaction(trans, ret);
3950 goto out;
3951 }
3952
3953 ret = btrfs_chunk_alloc_add_chunk_item(trans, bg);
3954 if (ret) {
3955 btrfs_abort_transaction(trans, ret);
3956 goto out;
3957 }
3958 } else if (ret) {
3959 btrfs_abort_transaction(trans, ret);
3960 goto out;
3961 }
3962 out:
3963 btrfs_trans_release_chunk_metadata(trans);
3964
3965 if (ret)
3966 return ERR_PTR(ret);
3967
3968 btrfs_get_block_group(bg);
3969 return bg;
3970 }
3971
3972 /*
3973 * Chunk allocation is done in 2 phases:
3974 *
3975 * 1) Phase 1 - through btrfs_chunk_alloc() we allocate device extents for
3976 * the chunk, the chunk mapping, create its block group and add the items
3977 * that belong in the chunk btree to it - more specifically, we need to
3978 * update device items in the chunk btree and add a new chunk item to it.
3979 *
3980 * 2) Phase 2 - through btrfs_create_pending_block_groups(), we add the block
3981 * group item to the extent btree and the device extent items to the devices
3982 * btree.
3983 *
3984 * This is done to prevent deadlocks. For example when COWing a node from the
3985 * extent btree we are holding a write lock on the node's parent and if we
3986 * trigger chunk allocation and attempted to insert the new block group item
3987 * in the extent btree right way, we could deadlock because the path for the
3988 * insertion can include that parent node. At first glance it seems impossible
3989 * to trigger chunk allocation after starting a transaction since tasks should
3990 * reserve enough transaction units (metadata space), however while that is true
3991 * most of the time, chunk allocation may still be triggered for several reasons:
3992 *
3993 * 1) When reserving metadata, we check if there is enough free space in the
3994 * metadata space_info and therefore don't trigger allocation of a new chunk.
3995 * However later when the task actually tries to COW an extent buffer from
3996 * the extent btree or from the device btree for example, it is forced to
3997 * allocate a new block group (chunk) because the only one that had enough
3998 * free space was just turned to RO mode by a running scrub for example (or
3999 * device replace, block group reclaim thread, etc), so we can not use it
4000 * for allocating an extent and end up being forced to allocate a new one;
4001 *
4002 * 2) Because we only check that the metadata space_info has enough free bytes,
4003 * we end up not allocating a new metadata chunk in that case. However if
4004 * the filesystem was mounted in degraded mode, none of the existing block
4005 * groups might be suitable for extent allocation due to their incompatible
4006 * profile (for e.g. mounting a 2 devices filesystem, where all block groups
4007 * use a RAID1 profile, in degraded mode using a single device). In this case
4008 * when the task attempts to COW some extent buffer of the extent btree for
4009 * example, it will trigger allocation of a new metadata block group with a
4010 * suitable profile (SINGLE profile in the example of the degraded mount of
4011 * the RAID1 filesystem);
4012 *
4013 * 3) The task has reserved enough transaction units / metadata space, but when
4014 * it attempts to COW an extent buffer from the extent or device btree for
4015 * example, it does not find any free extent in any metadata block group,
4016 * therefore forced to try to allocate a new metadata block group.
4017 * This is because some other task allocated all available extents in the
4018 * meanwhile - this typically happens with tasks that don't reserve space
4019 * properly, either intentionally or as a bug. One example where this is
4020 * done intentionally is fsync, as it does not reserve any transaction units
4021 * and ends up allocating a variable number of metadata extents for log
4022 * tree extent buffers;
4023 *
4024 * 4) The task has reserved enough transaction units / metadata space, but right
4025 * before it tries to allocate the last extent buffer it needs, a discard
4026 * operation comes in and, temporarily, removes the last free space entry from
4027 * the only metadata block group that had free space (discard starts by
4028 * removing a free space entry from a block group, then does the discard
4029 * operation and, once it's done, it adds back the free space entry to the
4030 * block group).
4031 *
4032 * We also need this 2 phases setup when adding a device to a filesystem with
4033 * a seed device - we must create new metadata and system chunks without adding
4034 * any of the block group items to the chunk, extent and device btrees. If we
4035 * did not do it this way, we would get ENOSPC when attempting to update those
4036 * btrees, since all the chunks from the seed device are read-only.
4037 *
4038 * Phase 1 does the updates and insertions to the chunk btree because if we had
4039 * it done in phase 2 and have a thundering herd of tasks allocating chunks in
4040 * parallel, we risk having too many system chunks allocated by many tasks if
4041 * many tasks reach phase 1 without the previous ones completing phase 2. In the
4042 * extreme case this leads to exhaustion of the system chunk array in the
4043 * superblock. This is easier to trigger if using a btree node/leaf size of 64K
4044 * and with RAID filesystems (so we have more device items in the chunk btree).
4045 * This has happened before and commit eafa4fd0ad0607 ("btrfs: fix exhaustion of
4046 * the system chunk array due to concurrent allocations") provides more details.
4047 *
4048 * Allocation of system chunks does not happen through this function. A task that
4049 * needs to update the chunk btree (the only btree that uses system chunks), must
4050 * preallocate chunk space by calling either check_system_chunk() or
4051 * btrfs_reserve_chunk_metadata() - the former is used when allocating a data or
4052 * metadata chunk or when removing a chunk, while the later is used before doing
4053 * a modification to the chunk btree - use cases for the later are adding,
4054 * removing and resizing a device as well as relocation of a system chunk.
4055 * See the comment below for more details.
4056 *
4057 * The reservation of system space, done through check_system_chunk(), as well
4058 * as all the updates and insertions into the chunk btree must be done while
4059 * holding fs_info->chunk_mutex. This is important to guarantee that while COWing
4060 * an extent buffer from the chunks btree we never trigger allocation of a new
4061 * system chunk, which would result in a deadlock (trying to lock twice an
4062 * extent buffer of the chunk btree, first time before triggering the chunk
4063 * allocation and the second time during chunk allocation while attempting to
4064 * update the chunks btree). The system chunk array is also updated while holding
4065 * that mutex. The same logic applies to removing chunks - we must reserve system
4066 * space, update the chunk btree and the system chunk array in the superblock
4067 * while holding fs_info->chunk_mutex.
4068 *
4069 * This function, btrfs_chunk_alloc(), belongs to phase 1.
4070 *
4071 * If @force is CHUNK_ALLOC_FORCE:
4072 * - return 1 if it successfully allocates a chunk,
4073 * - return errors including -ENOSPC otherwise.
4074 * If @force is NOT CHUNK_ALLOC_FORCE:
4075 * - return 0 if it doesn't need to allocate a new chunk,
4076 * - return 1 if it successfully allocates a chunk,
4077 * - return errors including -ENOSPC otherwise.
4078 */
4079 int btrfs_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags,
4080 enum btrfs_chunk_alloc_enum force)
4081 {
4082 struct btrfs_fs_info *fs_info = trans->fs_info;
4083 struct btrfs_space_info *space_info;
4084 struct btrfs_block_group *ret_bg;
4085 bool wait_for_alloc = false;
4086 bool should_alloc = false;
4087 bool from_extent_allocation = false;
4088 int ret = 0;
4089
4090 if (force == CHUNK_ALLOC_FORCE_FOR_EXTENT) {
4091 from_extent_allocation = true;
4092 force = CHUNK_ALLOC_FORCE;
4093 }
4094
4095 /* Don't re-enter if we're already allocating a chunk */
4096 if (trans->allocating_chunk)
4097 return -ENOSPC;
4098 /*
4099 * Allocation of system chunks can not happen through this path, as we
4100 * could end up in a deadlock if we are allocating a data or metadata
4101 * chunk and there is another task modifying the chunk btree.
4102 *
4103 * This is because while we are holding the chunk mutex, we will attempt
4104 * to add the new chunk item to the chunk btree or update an existing
4105 * device item in the chunk btree, while the other task that is modifying
4106 * the chunk btree is attempting to COW an extent buffer while holding a
4107 * lock on it and on its parent - if the COW operation triggers a system
4108 * chunk allocation, then we can deadlock because we are holding the
4109 * chunk mutex and we may need to access that extent buffer or its parent
4110 * in order to add the chunk item or update a device item.
4111 *
4112 * Tasks that want to modify the chunk tree should reserve system space
4113 * before updating the chunk btree, by calling either
4114 * btrfs_reserve_chunk_metadata() or check_system_chunk().
4115 * It's possible that after a task reserves the space, it still ends up
4116 * here - this happens in the cases described above at do_chunk_alloc().
4117 * The task will have to either retry or fail.
4118 */
4119 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4120 return -ENOSPC;
4121
4122 space_info = btrfs_find_space_info(fs_info, flags);
4123 ASSERT(space_info);
4124
4125 do {
4126 spin_lock(&space_info->lock);
4127 if (force < space_info->force_alloc)
4128 force = space_info->force_alloc;
4129 should_alloc = should_alloc_chunk(fs_info, space_info, force);
4130 if (space_info->full) {
4131 /* No more free physical space */
4132 if (should_alloc)
4133 ret = -ENOSPC;
4134 else
4135 ret = 0;
4136 spin_unlock(&space_info->lock);
4137 return ret;
4138 } else if (!should_alloc) {
4139 spin_unlock(&space_info->lock);
4140 return 0;
4141 } else if (space_info->chunk_alloc) {
4142 /*
4143 * Someone is already allocating, so we need to block
4144 * until this someone is finished and then loop to
4145 * recheck if we should continue with our allocation
4146 * attempt.
4147 */
4148 wait_for_alloc = true;
4149 force = CHUNK_ALLOC_NO_FORCE;
4150 spin_unlock(&space_info->lock);
4151 mutex_lock(&fs_info->chunk_mutex);
4152 mutex_unlock(&fs_info->chunk_mutex);
4153 } else {
4154 /* Proceed with allocation */
4155 space_info->chunk_alloc = 1;
4156 wait_for_alloc = false;
4157 spin_unlock(&space_info->lock);
4158 }
4159
4160 cond_resched();
4161 } while (wait_for_alloc);
4162
4163 mutex_lock(&fs_info->chunk_mutex);
4164 trans->allocating_chunk = true;
4165
4166 /*
4167 * If we have mixed data/metadata chunks we want to make sure we keep
4168 * allocating mixed chunks instead of individual chunks.
4169 */
4170 if (btrfs_mixed_space_info(space_info))
4171 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
4172
4173 /*
4174 * if we're doing a data chunk, go ahead and make sure that
4175 * we keep a reasonable number of metadata chunks allocated in the
4176 * FS as well.
4177 */
4178 if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
4179 fs_info->data_chunk_allocations++;
4180 if (!(fs_info->data_chunk_allocations %
4181 fs_info->metadata_ratio))
4182 force_metadata_allocation(fs_info);
4183 }
4184
4185 ret_bg = do_chunk_alloc(trans, flags);
4186 trans->allocating_chunk = false;
4187
4188 if (IS_ERR(ret_bg)) {
4189 ret = PTR_ERR(ret_bg);
4190 } else if (from_extent_allocation && (flags & BTRFS_BLOCK_GROUP_DATA)) {
4191 /*
4192 * New block group is likely to be used soon. Try to activate
4193 * it now. Failure is OK for now.
4194 */
4195 btrfs_zone_activate(ret_bg);
4196 }
4197
4198 if (!ret)
4199 btrfs_put_block_group(ret_bg);
4200
4201 spin_lock(&space_info->lock);
4202 if (ret < 0) {
4203 if (ret == -ENOSPC)
4204 space_info->full = 1;
4205 else
4206 goto out;
4207 } else {
4208 ret = 1;
4209 space_info->max_extent_size = 0;
4210 }
4211
4212 space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4213 out:
4214 space_info->chunk_alloc = 0;
4215 spin_unlock(&space_info->lock);
4216 mutex_unlock(&fs_info->chunk_mutex);
4217
4218 return ret;
4219 }
4220
4221 static u64 get_profile_num_devs(struct btrfs_fs_info *fs_info, u64 type)
4222 {
4223 u64 num_dev;
4224
4225 num_dev = btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)].devs_max;
4226 if (!num_dev)
4227 num_dev = fs_info->fs_devices->rw_devices;
4228
4229 return num_dev;
4230 }
4231
4232 static void reserve_chunk_space(struct btrfs_trans_handle *trans,
4233 u64 bytes,
4234 u64 type)
4235 {
4236 struct btrfs_fs_info *fs_info = trans->fs_info;
4237 struct btrfs_space_info *info;
4238 u64 left;
4239 int ret = 0;
4240
4241 /*
4242 * Needed because we can end up allocating a system chunk and for an
4243 * atomic and race free space reservation in the chunk block reserve.
4244 */
4245 lockdep_assert_held(&fs_info->chunk_mutex);
4246
4247 info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4248 spin_lock(&info->lock);
4249 left = info->total_bytes - btrfs_space_info_used(info, true);
4250 spin_unlock(&info->lock);
4251
4252 if (left < bytes && btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
4253 btrfs_info(fs_info, "left=%llu, need=%llu, flags=%llu",
4254 left, bytes, type);
4255 btrfs_dump_space_info(fs_info, info, 0, 0);
4256 }
4257
4258 if (left < bytes) {
4259 u64 flags = btrfs_system_alloc_profile(fs_info);
4260 struct btrfs_block_group *bg;
4261
4262 /*
4263 * Ignore failure to create system chunk. We might end up not
4264 * needing it, as we might not need to COW all nodes/leafs from
4265 * the paths we visit in the chunk tree (they were already COWed
4266 * or created in the current transaction for example).
4267 */
4268 bg = btrfs_create_chunk(trans, flags);
4269 if (IS_ERR(bg)) {
4270 ret = PTR_ERR(bg);
4271 } else {
4272 /*
4273 * We have a new chunk. We also need to activate it for
4274 * zoned filesystem.
4275 */
4276 ret = btrfs_zoned_activate_one_bg(fs_info, info, true);
4277 if (ret < 0)
4278 return;
4279
4280 /*
4281 * If we fail to add the chunk item here, we end up
4282 * trying again at phase 2 of chunk allocation, at
4283 * btrfs_create_pending_block_groups(). So ignore
4284 * any error here. An ENOSPC here could happen, due to
4285 * the cases described at do_chunk_alloc() - the system
4286 * block group we just created was just turned into RO
4287 * mode by a scrub for example, or a running discard
4288 * temporarily removed its free space entries, etc.
4289 */
4290 btrfs_chunk_alloc_add_chunk_item(trans, bg);
4291 }
4292 }
4293
4294 if (!ret) {
4295 ret = btrfs_block_rsv_add(fs_info,
4296 &fs_info->chunk_block_rsv,
4297 bytes, BTRFS_RESERVE_NO_FLUSH);
4298 if (!ret)
4299 trans->chunk_bytes_reserved += bytes;
4300 }
4301 }
4302
4303 /*
4304 * Reserve space in the system space for allocating or removing a chunk.
4305 * The caller must be holding fs_info->chunk_mutex.
4306 */
4307 void check_system_chunk(struct btrfs_trans_handle *trans, u64 type)
4308 {
4309 struct btrfs_fs_info *fs_info = trans->fs_info;
4310 const u64 num_devs = get_profile_num_devs(fs_info, type);
4311 u64 bytes;
4312
4313 /* num_devs device items to update and 1 chunk item to add or remove. */
4314 bytes = btrfs_calc_metadata_size(fs_info, num_devs) +
4315 btrfs_calc_insert_metadata_size(fs_info, 1);
4316
4317 reserve_chunk_space(trans, bytes, type);
4318 }
4319
4320 /*
4321 * Reserve space in the system space, if needed, for doing a modification to the
4322 * chunk btree.
4323 *
4324 * @trans: A transaction handle.
4325 * @is_item_insertion: Indicate if the modification is for inserting a new item
4326 * in the chunk btree or if it's for the deletion or update
4327 * of an existing item.
4328 *
4329 * This is used in a context where we need to update the chunk btree outside
4330 * block group allocation and removal, to avoid a deadlock with a concurrent
4331 * task that is allocating a metadata or data block group and therefore needs to
4332 * update the chunk btree while holding the chunk mutex. After the update to the
4333 * chunk btree is done, btrfs_trans_release_chunk_metadata() should be called.
4334 *
4335 */
4336 void btrfs_reserve_chunk_metadata(struct btrfs_trans_handle *trans,
4337 bool is_item_insertion)
4338 {
4339 struct btrfs_fs_info *fs_info = trans->fs_info;
4340 u64 bytes;
4341
4342 if (is_item_insertion)
4343 bytes = btrfs_calc_insert_metadata_size(fs_info, 1);
4344 else
4345 bytes = btrfs_calc_metadata_size(fs_info, 1);
4346
4347 mutex_lock(&fs_info->chunk_mutex);
4348 reserve_chunk_space(trans, bytes, BTRFS_BLOCK_GROUP_SYSTEM);
4349 mutex_unlock(&fs_info->chunk_mutex);
4350 }
4351
4352 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
4353 {
4354 struct btrfs_block_group *block_group;
4355
4356 block_group = btrfs_lookup_first_block_group(info, 0);
4357 while (block_group) {
4358 btrfs_wait_block_group_cache_done(block_group);
4359 spin_lock(&block_group->lock);
4360 if (test_and_clear_bit(BLOCK_GROUP_FLAG_IREF,
4361 &block_group->runtime_flags)) {
4362 struct btrfs_inode *inode = block_group->inode;
4363
4364 block_group->inode = NULL;
4365 spin_unlock(&block_group->lock);
4366
4367 ASSERT(block_group->io_ctl.inode == NULL);
4368 iput(&inode->vfs_inode);
4369 } else {
4370 spin_unlock(&block_group->lock);
4371 }
4372 block_group = btrfs_next_block_group(block_group);
4373 }
4374 }
4375
4376 /*
4377 * Must be called only after stopping all workers, since we could have block
4378 * group caching kthreads running, and therefore they could race with us if we
4379 * freed the block groups before stopping them.
4380 */
4381 int btrfs_free_block_groups(struct btrfs_fs_info *info)
4382 {
4383 struct btrfs_block_group *block_group;
4384 struct btrfs_space_info *space_info;
4385 struct btrfs_caching_control *caching_ctl;
4386 struct rb_node *n;
4387
4388 if (btrfs_is_zoned(info)) {
4389 if (info->active_meta_bg) {
4390 btrfs_put_block_group(info->active_meta_bg);
4391 info->active_meta_bg = NULL;
4392 }
4393 if (info->active_system_bg) {
4394 btrfs_put_block_group(info->active_system_bg);
4395 info->active_system_bg = NULL;
4396 }
4397 }
4398
4399 write_lock(&info->block_group_cache_lock);
4400 while (!list_empty(&info->caching_block_groups)) {
4401 caching_ctl = list_entry(info->caching_block_groups.next,
4402 struct btrfs_caching_control, list);
4403 list_del(&caching_ctl->list);
4404 btrfs_put_caching_control(caching_ctl);
4405 }
4406 write_unlock(&info->block_group_cache_lock);
4407
4408 spin_lock(&info->unused_bgs_lock);
4409 while (!list_empty(&info->unused_bgs)) {
4410 block_group = list_first_entry(&info->unused_bgs,
4411 struct btrfs_block_group,
4412 bg_list);
4413 list_del_init(&block_group->bg_list);
4414 btrfs_put_block_group(block_group);
4415 }
4416
4417 while (!list_empty(&info->reclaim_bgs)) {
4418 block_group = list_first_entry(&info->reclaim_bgs,
4419 struct btrfs_block_group,
4420 bg_list);
4421 list_del_init(&block_group->bg_list);
4422 btrfs_put_block_group(block_group);
4423 }
4424 spin_unlock(&info->unused_bgs_lock);
4425
4426 spin_lock(&info->zone_active_bgs_lock);
4427 while (!list_empty(&info->zone_active_bgs)) {
4428 block_group = list_first_entry(&info->zone_active_bgs,
4429 struct btrfs_block_group,
4430 active_bg_list);
4431 list_del_init(&block_group->active_bg_list);
4432 btrfs_put_block_group(block_group);
4433 }
4434 spin_unlock(&info->zone_active_bgs_lock);
4435
4436 write_lock(&info->block_group_cache_lock);
4437 while ((n = rb_last(&info->block_group_cache_tree.rb_root)) != NULL) {
4438 block_group = rb_entry(n, struct btrfs_block_group,
4439 cache_node);
4440 rb_erase_cached(&block_group->cache_node,
4441 &info->block_group_cache_tree);
4442 RB_CLEAR_NODE(&block_group->cache_node);
4443 write_unlock(&info->block_group_cache_lock);
4444
4445 down_write(&block_group->space_info->groups_sem);
4446 list_del(&block_group->list);
4447 up_write(&block_group->space_info->groups_sem);
4448
4449 /*
4450 * We haven't cached this block group, which means we could
4451 * possibly have excluded extents on this block group.
4452 */
4453 if (block_group->cached == BTRFS_CACHE_NO ||
4454 block_group->cached == BTRFS_CACHE_ERROR)
4455 btrfs_free_excluded_extents(block_group);
4456
4457 btrfs_remove_free_space_cache(block_group);
4458 ASSERT(block_group->cached != BTRFS_CACHE_STARTED);
4459 ASSERT(list_empty(&block_group->dirty_list));
4460 ASSERT(list_empty(&block_group->io_list));
4461 ASSERT(list_empty(&block_group->bg_list));
4462 ASSERT(refcount_read(&block_group->refs) == 1);
4463 ASSERT(block_group->swap_extents == 0);
4464 btrfs_put_block_group(block_group);
4465
4466 write_lock(&info->block_group_cache_lock);
4467 }
4468 write_unlock(&info->block_group_cache_lock);
4469
4470 btrfs_release_global_block_rsv(info);
4471
4472 while (!list_empty(&info->space_info)) {
4473 space_info = list_entry(info->space_info.next,
4474 struct btrfs_space_info,
4475 list);
4476
4477 /*
4478 * Do not hide this behind enospc_debug, this is actually
4479 * important and indicates a real bug if this happens.
4480 */
4481 if (WARN_ON(space_info->bytes_pinned > 0 ||
4482 space_info->bytes_may_use > 0))
4483 btrfs_dump_space_info(info, space_info, 0, 0);
4484
4485 /*
4486 * If there was a failure to cleanup a log tree, very likely due
4487 * to an IO failure on a writeback attempt of one or more of its
4488 * extent buffers, we could not do proper (and cheap) unaccounting
4489 * of their reserved space, so don't warn on bytes_reserved > 0 in
4490 * that case.
4491 */
4492 if (!(space_info->flags & BTRFS_BLOCK_GROUP_METADATA) ||
4493 !BTRFS_FS_LOG_CLEANUP_ERROR(info)) {
4494 if (WARN_ON(space_info->bytes_reserved > 0))
4495 btrfs_dump_space_info(info, space_info, 0, 0);
4496 }
4497
4498 WARN_ON(space_info->reclaim_size > 0);
4499 list_del(&space_info->list);
4500 btrfs_sysfs_remove_space_info(space_info);
4501 }
4502 return 0;
4503 }
4504
4505 void btrfs_freeze_block_group(struct btrfs_block_group *cache)
4506 {
4507 atomic_inc(&cache->frozen);
4508 }
4509
4510 void btrfs_unfreeze_block_group(struct btrfs_block_group *block_group)
4511 {
4512 struct btrfs_fs_info *fs_info = block_group->fs_info;
4513 bool cleanup;
4514
4515 spin_lock(&block_group->lock);
4516 cleanup = (atomic_dec_and_test(&block_group->frozen) &&
4517 test_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags));
4518 spin_unlock(&block_group->lock);
4519
4520 if (cleanup) {
4521 struct btrfs_chunk_map *map;
4522
4523 map = btrfs_find_chunk_map(fs_info, block_group->start, 1);
4524 /* Logic error, can't happen. */
4525 ASSERT(map);
4526
4527 btrfs_remove_chunk_map(fs_info, map);
4528
4529 /* Once for our lookup reference. */
4530 btrfs_free_chunk_map(map);
4531
4532 /*
4533 * We may have left one free space entry and other possible
4534 * tasks trimming this block group have left 1 entry each one.
4535 * Free them if any.
4536 */
4537 btrfs_remove_free_space_cache(block_group);
4538 }
4539 }
4540
4541 bool btrfs_inc_block_group_swap_extents(struct btrfs_block_group *bg)
4542 {
4543 bool ret = true;
4544
4545 spin_lock(&bg->lock);
4546 if (bg->ro)
4547 ret = false;
4548 else
4549 bg->swap_extents++;
4550 spin_unlock(&bg->lock);
4551
4552 return ret;
4553 }
4554
4555 void btrfs_dec_block_group_swap_extents(struct btrfs_block_group *bg, int amount)
4556 {
4557 spin_lock(&bg->lock);
4558 ASSERT(!bg->ro);
4559 ASSERT(bg->swap_extents >= amount);
4560 bg->swap_extents -= amount;
4561 spin_unlock(&bg->lock);
4562 }
4563
4564 enum btrfs_block_group_size_class btrfs_calc_block_group_size_class(u64 size)
4565 {
4566 if (size <= SZ_128K)
4567 return BTRFS_BG_SZ_SMALL;
4568 if (size <= SZ_8M)
4569 return BTRFS_BG_SZ_MEDIUM;
4570 return BTRFS_BG_SZ_LARGE;
4571 }
4572
4573 /*
4574 * Handle a block group allocating an extent in a size class
4575 *
4576 * @bg: The block group we allocated in.
4577 * @size_class: The size class of the allocation.
4578 * @force_wrong_size_class: Whether we are desperate enough to allow
4579 * mismatched size classes.
4580 *
4581 * Returns: 0 if the size class was valid for this block_group, -EAGAIN in the
4582 * case of a race that leads to the wrong size class without
4583 * force_wrong_size_class set.
4584 *
4585 * find_free_extent will skip block groups with a mismatched size class until
4586 * it really needs to avoid ENOSPC. In that case it will set
4587 * force_wrong_size_class. However, if a block group is newly allocated and
4588 * doesn't yet have a size class, then it is possible for two allocations of
4589 * different sizes to race and both try to use it. The loser is caught here and
4590 * has to retry.
4591 */
4592 int btrfs_use_block_group_size_class(struct btrfs_block_group *bg,
4593 enum btrfs_block_group_size_class size_class,
4594 bool force_wrong_size_class)
4595 {
4596 ASSERT(size_class != BTRFS_BG_SZ_NONE);
4597
4598 /* The new allocation is in the right size class, do nothing */
4599 if (bg->size_class == size_class)
4600 return 0;
4601 /*
4602 * The new allocation is in a mismatched size class.
4603 * This means one of two things:
4604 *
4605 * 1. Two tasks in find_free_extent for different size_classes raced
4606 * and hit the same empty block_group. Make the loser try again.
4607 * 2. A call to find_free_extent got desperate enough to set
4608 * 'force_wrong_slab'. Don't change the size_class, but allow the
4609 * allocation.
4610 */
4611 if (bg->size_class != BTRFS_BG_SZ_NONE) {
4612 if (force_wrong_size_class)
4613 return 0;
4614 return -EAGAIN;
4615 }
4616 /*
4617 * The happy new block group case: the new allocation is the first
4618 * one in the block_group so we set size_class.
4619 */
4620 bg->size_class = size_class;
4621
4622 return 0;
4623 }
4624
4625 bool btrfs_block_group_should_use_size_class(struct btrfs_block_group *bg)
4626 {
4627 if (btrfs_is_zoned(bg->fs_info))
4628 return false;
4629 if (!btrfs_is_block_group_data_only(bg))
4630 return false;
4631 return true;
4632 }
4633
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