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Btrfs: fix memory leak in reading btree blocks
[deliverable/linux.git] / fs / btrfs / extent-tree.c
1 /*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18 #include <linux/sched.h>
19 #include <linux/pagemap.h>
20 #include <linux/writeback.h>
21 #include <linux/blkdev.h>
22 #include <linux/sort.h>
23 #include <linux/rcupdate.h>
24 #include <linux/kthread.h>
25 #include <linux/slab.h>
26 #include <linux/ratelimit.h>
27 #include <linux/percpu_counter.h>
28 #include "hash.h"
29 #include "tree-log.h"
30 #include "disk-io.h"
31 #include "print-tree.h"
32 #include "volumes.h"
33 #include "raid56.h"
34 #include "locking.h"
35 #include "free-space-cache.h"
36 #include "free-space-tree.h"
37 #include "math.h"
38 #include "sysfs.h"
39 #include "qgroup.h"
40
41 #undef SCRAMBLE_DELAYED_REFS
42
43 /*
44 * control flags for do_chunk_alloc's force field
45 * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
46 * if we really need one.
47 *
48 * CHUNK_ALLOC_LIMITED means to only try and allocate one
49 * if we have very few chunks already allocated. This is
50 * used as part of the clustering code to help make sure
51 * we have a good pool of storage to cluster in, without
52 * filling the FS with empty chunks
53 *
54 * CHUNK_ALLOC_FORCE means it must try to allocate one
55 *
56 */
57 enum {
58 CHUNK_ALLOC_NO_FORCE = 0,
59 CHUNK_ALLOC_LIMITED = 1,
60 CHUNK_ALLOC_FORCE = 2,
61 };
62
63 static int update_block_group(struct btrfs_trans_handle *trans,
64 struct btrfs_root *root, u64 bytenr,
65 u64 num_bytes, int alloc);
66 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
67 struct btrfs_root *root,
68 struct btrfs_delayed_ref_node *node, u64 parent,
69 u64 root_objectid, u64 owner_objectid,
70 u64 owner_offset, int refs_to_drop,
71 struct btrfs_delayed_extent_op *extra_op);
72 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
73 struct extent_buffer *leaf,
74 struct btrfs_extent_item *ei);
75 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
76 struct btrfs_root *root,
77 u64 parent, u64 root_objectid,
78 u64 flags, u64 owner, u64 offset,
79 struct btrfs_key *ins, int ref_mod);
80 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
81 struct btrfs_root *root,
82 u64 parent, u64 root_objectid,
83 u64 flags, struct btrfs_disk_key *key,
84 int level, struct btrfs_key *ins);
85 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
86 struct btrfs_root *extent_root, u64 flags,
87 int force);
88 static int find_next_key(struct btrfs_path *path, int level,
89 struct btrfs_key *key);
90 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
91 int dump_block_groups);
92 static int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
93 u64 ram_bytes, u64 num_bytes, int delalloc);
94 static int btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
95 u64 num_bytes, int delalloc);
96 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
97 u64 num_bytes);
98 int btrfs_pin_extent(struct btrfs_root *root,
99 u64 bytenr, u64 num_bytes, int reserved);
100 static int __reserve_metadata_bytes(struct btrfs_root *root,
101 struct btrfs_space_info *space_info,
102 u64 orig_bytes,
103 enum btrfs_reserve_flush_enum flush);
104 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
105 struct btrfs_space_info *space_info,
106 u64 num_bytes);
107 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
108 struct btrfs_space_info *space_info,
109 u64 num_bytes);
110
111 static noinline int
112 block_group_cache_done(struct btrfs_block_group_cache *cache)
113 {
114 smp_mb();
115 return cache->cached == BTRFS_CACHE_FINISHED ||
116 cache->cached == BTRFS_CACHE_ERROR;
117 }
118
119 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
120 {
121 return (cache->flags & bits) == bits;
122 }
123
124 void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
125 {
126 atomic_inc(&cache->count);
127 }
128
129 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
130 {
131 if (atomic_dec_and_test(&cache->count)) {
132 WARN_ON(cache->pinned > 0);
133 WARN_ON(cache->reserved > 0);
134 kfree(cache->free_space_ctl);
135 kfree(cache);
136 }
137 }
138
139 /*
140 * this adds the block group to the fs_info rb tree for the block group
141 * cache
142 */
143 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
144 struct btrfs_block_group_cache *block_group)
145 {
146 struct rb_node **p;
147 struct rb_node *parent = NULL;
148 struct btrfs_block_group_cache *cache;
149
150 spin_lock(&info->block_group_cache_lock);
151 p = &info->block_group_cache_tree.rb_node;
152
153 while (*p) {
154 parent = *p;
155 cache = rb_entry(parent, struct btrfs_block_group_cache,
156 cache_node);
157 if (block_group->key.objectid < cache->key.objectid) {
158 p = &(*p)->rb_left;
159 } else if (block_group->key.objectid > cache->key.objectid) {
160 p = &(*p)->rb_right;
161 } else {
162 spin_unlock(&info->block_group_cache_lock);
163 return -EEXIST;
164 }
165 }
166
167 rb_link_node(&block_group->cache_node, parent, p);
168 rb_insert_color(&block_group->cache_node,
169 &info->block_group_cache_tree);
170
171 if (info->first_logical_byte > block_group->key.objectid)
172 info->first_logical_byte = block_group->key.objectid;
173
174 spin_unlock(&info->block_group_cache_lock);
175
176 return 0;
177 }
178
179 /*
180 * This will return the block group at or after bytenr if contains is 0, else
181 * it will return the block group that contains the bytenr
182 */
183 static struct btrfs_block_group_cache *
184 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
185 int contains)
186 {
187 struct btrfs_block_group_cache *cache, *ret = NULL;
188 struct rb_node *n;
189 u64 end, start;
190
191 spin_lock(&info->block_group_cache_lock);
192 n = info->block_group_cache_tree.rb_node;
193
194 while (n) {
195 cache = rb_entry(n, struct btrfs_block_group_cache,
196 cache_node);
197 end = cache->key.objectid + cache->key.offset - 1;
198 start = cache->key.objectid;
199
200 if (bytenr < start) {
201 if (!contains && (!ret || start < ret->key.objectid))
202 ret = cache;
203 n = n->rb_left;
204 } else if (bytenr > start) {
205 if (contains && bytenr <= end) {
206 ret = cache;
207 break;
208 }
209 n = n->rb_right;
210 } else {
211 ret = cache;
212 break;
213 }
214 }
215 if (ret) {
216 btrfs_get_block_group(ret);
217 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
218 info->first_logical_byte = ret->key.objectid;
219 }
220 spin_unlock(&info->block_group_cache_lock);
221
222 return ret;
223 }
224
225 static int add_excluded_extent(struct btrfs_root *root,
226 u64 start, u64 num_bytes)
227 {
228 u64 end = start + num_bytes - 1;
229 set_extent_bits(&root->fs_info->freed_extents[0],
230 start, end, EXTENT_UPTODATE);
231 set_extent_bits(&root->fs_info->freed_extents[1],
232 start, end, EXTENT_UPTODATE);
233 return 0;
234 }
235
236 static void free_excluded_extents(struct btrfs_root *root,
237 struct btrfs_block_group_cache *cache)
238 {
239 u64 start, end;
240
241 start = cache->key.objectid;
242 end = start + cache->key.offset - 1;
243
244 clear_extent_bits(&root->fs_info->freed_extents[0],
245 start, end, EXTENT_UPTODATE);
246 clear_extent_bits(&root->fs_info->freed_extents[1],
247 start, end, EXTENT_UPTODATE);
248 }
249
250 static int exclude_super_stripes(struct btrfs_root *root,
251 struct btrfs_block_group_cache *cache)
252 {
253 u64 bytenr;
254 u64 *logical;
255 int stripe_len;
256 int i, nr, ret;
257
258 if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
259 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
260 cache->bytes_super += stripe_len;
261 ret = add_excluded_extent(root, cache->key.objectid,
262 stripe_len);
263 if (ret)
264 return ret;
265 }
266
267 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
268 bytenr = btrfs_sb_offset(i);
269 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
270 cache->key.objectid, bytenr,
271 0, &logical, &nr, &stripe_len);
272 if (ret)
273 return ret;
274
275 while (nr--) {
276 u64 start, len;
277
278 if (logical[nr] > cache->key.objectid +
279 cache->key.offset)
280 continue;
281
282 if (logical[nr] + stripe_len <= cache->key.objectid)
283 continue;
284
285 start = logical[nr];
286 if (start < cache->key.objectid) {
287 start = cache->key.objectid;
288 len = (logical[nr] + stripe_len) - start;
289 } else {
290 len = min_t(u64, stripe_len,
291 cache->key.objectid +
292 cache->key.offset - start);
293 }
294
295 cache->bytes_super += len;
296 ret = add_excluded_extent(root, start, len);
297 if (ret) {
298 kfree(logical);
299 return ret;
300 }
301 }
302
303 kfree(logical);
304 }
305 return 0;
306 }
307
308 static struct btrfs_caching_control *
309 get_caching_control(struct btrfs_block_group_cache *cache)
310 {
311 struct btrfs_caching_control *ctl;
312
313 spin_lock(&cache->lock);
314 if (!cache->caching_ctl) {
315 spin_unlock(&cache->lock);
316 return NULL;
317 }
318
319 ctl = cache->caching_ctl;
320 atomic_inc(&ctl->count);
321 spin_unlock(&cache->lock);
322 return ctl;
323 }
324
325 static void put_caching_control(struct btrfs_caching_control *ctl)
326 {
327 if (atomic_dec_and_test(&ctl->count))
328 kfree(ctl);
329 }
330
331 #ifdef CONFIG_BTRFS_DEBUG
332 static void fragment_free_space(struct btrfs_root *root,
333 struct btrfs_block_group_cache *block_group)
334 {
335 u64 start = block_group->key.objectid;
336 u64 len = block_group->key.offset;
337 u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ?
338 root->nodesize : root->sectorsize;
339 u64 step = chunk << 1;
340
341 while (len > chunk) {
342 btrfs_remove_free_space(block_group, start, chunk);
343 start += step;
344 if (len < step)
345 len = 0;
346 else
347 len -= step;
348 }
349 }
350 #endif
351
352 /*
353 * this is only called by cache_block_group, since we could have freed extents
354 * we need to check the pinned_extents for any extents that can't be used yet
355 * since their free space will be released as soon as the transaction commits.
356 */
357 u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
358 struct btrfs_fs_info *info, u64 start, u64 end)
359 {
360 u64 extent_start, extent_end, size, total_added = 0;
361 int ret;
362
363 while (start < end) {
364 ret = find_first_extent_bit(info->pinned_extents, start,
365 &extent_start, &extent_end,
366 EXTENT_DIRTY | EXTENT_UPTODATE,
367 NULL);
368 if (ret)
369 break;
370
371 if (extent_start <= start) {
372 start = extent_end + 1;
373 } else if (extent_start > start && extent_start < end) {
374 size = extent_start - start;
375 total_added += size;
376 ret = btrfs_add_free_space(block_group, start,
377 size);
378 BUG_ON(ret); /* -ENOMEM or logic error */
379 start = extent_end + 1;
380 } else {
381 break;
382 }
383 }
384
385 if (start < end) {
386 size = end - start;
387 total_added += size;
388 ret = btrfs_add_free_space(block_group, start, size);
389 BUG_ON(ret); /* -ENOMEM or logic error */
390 }
391
392 return total_added;
393 }
394
395 static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl)
396 {
397 struct btrfs_block_group_cache *block_group;
398 struct btrfs_fs_info *fs_info;
399 struct btrfs_root *extent_root;
400 struct btrfs_path *path;
401 struct extent_buffer *leaf;
402 struct btrfs_key key;
403 u64 total_found = 0;
404 u64 last = 0;
405 u32 nritems;
406 int ret;
407 bool wakeup = true;
408
409 block_group = caching_ctl->block_group;
410 fs_info = block_group->fs_info;
411 extent_root = fs_info->extent_root;
412
413 path = btrfs_alloc_path();
414 if (!path)
415 return -ENOMEM;
416
417 last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
418
419 #ifdef CONFIG_BTRFS_DEBUG
420 /*
421 * If we're fragmenting we don't want to make anybody think we can
422 * allocate from this block group until we've had a chance to fragment
423 * the free space.
424 */
425 if (btrfs_should_fragment_free_space(extent_root, block_group))
426 wakeup = false;
427 #endif
428 /*
429 * We don't want to deadlock with somebody trying to allocate a new
430 * extent for the extent root while also trying to search the extent
431 * root to add free space. So we skip locking and search the commit
432 * root, since its read-only
433 */
434 path->skip_locking = 1;
435 path->search_commit_root = 1;
436 path->reada = READA_FORWARD;
437
438 key.objectid = last;
439 key.offset = 0;
440 key.type = BTRFS_EXTENT_ITEM_KEY;
441
442 next:
443 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
444 if (ret < 0)
445 goto out;
446
447 leaf = path->nodes[0];
448 nritems = btrfs_header_nritems(leaf);
449
450 while (1) {
451 if (btrfs_fs_closing(fs_info) > 1) {
452 last = (u64)-1;
453 break;
454 }
455
456 if (path->slots[0] < nritems) {
457 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
458 } else {
459 ret = find_next_key(path, 0, &key);
460 if (ret)
461 break;
462
463 if (need_resched() ||
464 rwsem_is_contended(&fs_info->commit_root_sem)) {
465 if (wakeup)
466 caching_ctl->progress = last;
467 btrfs_release_path(path);
468 up_read(&fs_info->commit_root_sem);
469 mutex_unlock(&caching_ctl->mutex);
470 cond_resched();
471 mutex_lock(&caching_ctl->mutex);
472 down_read(&fs_info->commit_root_sem);
473 goto next;
474 }
475
476 ret = btrfs_next_leaf(extent_root, path);
477 if (ret < 0)
478 goto out;
479 if (ret)
480 break;
481 leaf = path->nodes[0];
482 nritems = btrfs_header_nritems(leaf);
483 continue;
484 }
485
486 if (key.objectid < last) {
487 key.objectid = last;
488 key.offset = 0;
489 key.type = BTRFS_EXTENT_ITEM_KEY;
490
491 if (wakeup)
492 caching_ctl->progress = last;
493 btrfs_release_path(path);
494 goto next;
495 }
496
497 if (key.objectid < block_group->key.objectid) {
498 path->slots[0]++;
499 continue;
500 }
501
502 if (key.objectid >= block_group->key.objectid +
503 block_group->key.offset)
504 break;
505
506 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
507 key.type == BTRFS_METADATA_ITEM_KEY) {
508 total_found += add_new_free_space(block_group,
509 fs_info, last,
510 key.objectid);
511 if (key.type == BTRFS_METADATA_ITEM_KEY)
512 last = key.objectid +
513 fs_info->tree_root->nodesize;
514 else
515 last = key.objectid + key.offset;
516
517 if (total_found > CACHING_CTL_WAKE_UP) {
518 total_found = 0;
519 if (wakeup)
520 wake_up(&caching_ctl->wait);
521 }
522 }
523 path->slots[0]++;
524 }
525 ret = 0;
526
527 total_found += add_new_free_space(block_group, fs_info, last,
528 block_group->key.objectid +
529 block_group->key.offset);
530 caching_ctl->progress = (u64)-1;
531
532 out:
533 btrfs_free_path(path);
534 return ret;
535 }
536
537 static noinline void caching_thread(struct btrfs_work *work)
538 {
539 struct btrfs_block_group_cache *block_group;
540 struct btrfs_fs_info *fs_info;
541 struct btrfs_caching_control *caching_ctl;
542 struct btrfs_root *extent_root;
543 int ret;
544
545 caching_ctl = container_of(work, struct btrfs_caching_control, work);
546 block_group = caching_ctl->block_group;
547 fs_info = block_group->fs_info;
548 extent_root = fs_info->extent_root;
549
550 mutex_lock(&caching_ctl->mutex);
551 down_read(&fs_info->commit_root_sem);
552
553 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
554 ret = load_free_space_tree(caching_ctl);
555 else
556 ret = load_extent_tree_free(caching_ctl);
557
558 spin_lock(&block_group->lock);
559 block_group->caching_ctl = NULL;
560 block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED;
561 spin_unlock(&block_group->lock);
562
563 #ifdef CONFIG_BTRFS_DEBUG
564 if (btrfs_should_fragment_free_space(extent_root, block_group)) {
565 u64 bytes_used;
566
567 spin_lock(&block_group->space_info->lock);
568 spin_lock(&block_group->lock);
569 bytes_used = block_group->key.offset -
570 btrfs_block_group_used(&block_group->item);
571 block_group->space_info->bytes_used += bytes_used >> 1;
572 spin_unlock(&block_group->lock);
573 spin_unlock(&block_group->space_info->lock);
574 fragment_free_space(extent_root, block_group);
575 }
576 #endif
577
578 caching_ctl->progress = (u64)-1;
579
580 up_read(&fs_info->commit_root_sem);
581 free_excluded_extents(fs_info->extent_root, block_group);
582 mutex_unlock(&caching_ctl->mutex);
583
584 wake_up(&caching_ctl->wait);
585
586 put_caching_control(caching_ctl);
587 btrfs_put_block_group(block_group);
588 }
589
590 static int cache_block_group(struct btrfs_block_group_cache *cache,
591 int load_cache_only)
592 {
593 DEFINE_WAIT(wait);
594 struct btrfs_fs_info *fs_info = cache->fs_info;
595 struct btrfs_caching_control *caching_ctl;
596 int ret = 0;
597
598 caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
599 if (!caching_ctl)
600 return -ENOMEM;
601
602 INIT_LIST_HEAD(&caching_ctl->list);
603 mutex_init(&caching_ctl->mutex);
604 init_waitqueue_head(&caching_ctl->wait);
605 caching_ctl->block_group = cache;
606 caching_ctl->progress = cache->key.objectid;
607 atomic_set(&caching_ctl->count, 1);
608 btrfs_init_work(&caching_ctl->work, btrfs_cache_helper,
609 caching_thread, NULL, NULL);
610
611 spin_lock(&cache->lock);
612 /*
613 * This should be a rare occasion, but this could happen I think in the
614 * case where one thread starts to load the space cache info, and then
615 * some other thread starts a transaction commit which tries to do an
616 * allocation while the other thread is still loading the space cache
617 * info. The previous loop should have kept us from choosing this block
618 * group, but if we've moved to the state where we will wait on caching
619 * block groups we need to first check if we're doing a fast load here,
620 * so we can wait for it to finish, otherwise we could end up allocating
621 * from a block group who's cache gets evicted for one reason or
622 * another.
623 */
624 while (cache->cached == BTRFS_CACHE_FAST) {
625 struct btrfs_caching_control *ctl;
626
627 ctl = cache->caching_ctl;
628 atomic_inc(&ctl->count);
629 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
630 spin_unlock(&cache->lock);
631
632 schedule();
633
634 finish_wait(&ctl->wait, &wait);
635 put_caching_control(ctl);
636 spin_lock(&cache->lock);
637 }
638
639 if (cache->cached != BTRFS_CACHE_NO) {
640 spin_unlock(&cache->lock);
641 kfree(caching_ctl);
642 return 0;
643 }
644 WARN_ON(cache->caching_ctl);
645 cache->caching_ctl = caching_ctl;
646 cache->cached = BTRFS_CACHE_FAST;
647 spin_unlock(&cache->lock);
648
649 if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
650 mutex_lock(&caching_ctl->mutex);
651 ret = load_free_space_cache(fs_info, cache);
652
653 spin_lock(&cache->lock);
654 if (ret == 1) {
655 cache->caching_ctl = NULL;
656 cache->cached = BTRFS_CACHE_FINISHED;
657 cache->last_byte_to_unpin = (u64)-1;
658 caching_ctl->progress = (u64)-1;
659 } else {
660 if (load_cache_only) {
661 cache->caching_ctl = NULL;
662 cache->cached = BTRFS_CACHE_NO;
663 } else {
664 cache->cached = BTRFS_CACHE_STARTED;
665 cache->has_caching_ctl = 1;
666 }
667 }
668 spin_unlock(&cache->lock);
669 #ifdef CONFIG_BTRFS_DEBUG
670 if (ret == 1 &&
671 btrfs_should_fragment_free_space(fs_info->extent_root,
672 cache)) {
673 u64 bytes_used;
674
675 spin_lock(&cache->space_info->lock);
676 spin_lock(&cache->lock);
677 bytes_used = cache->key.offset -
678 btrfs_block_group_used(&cache->item);
679 cache->space_info->bytes_used += bytes_used >> 1;
680 spin_unlock(&cache->lock);
681 spin_unlock(&cache->space_info->lock);
682 fragment_free_space(fs_info->extent_root, cache);
683 }
684 #endif
685 mutex_unlock(&caching_ctl->mutex);
686
687 wake_up(&caching_ctl->wait);
688 if (ret == 1) {
689 put_caching_control(caching_ctl);
690 free_excluded_extents(fs_info->extent_root, cache);
691 return 0;
692 }
693 } else {
694 /*
695 * We're either using the free space tree or no caching at all.
696 * Set cached to the appropriate value and wakeup any waiters.
697 */
698 spin_lock(&cache->lock);
699 if (load_cache_only) {
700 cache->caching_ctl = NULL;
701 cache->cached = BTRFS_CACHE_NO;
702 } else {
703 cache->cached = BTRFS_CACHE_STARTED;
704 cache->has_caching_ctl = 1;
705 }
706 spin_unlock(&cache->lock);
707 wake_up(&caching_ctl->wait);
708 }
709
710 if (load_cache_only) {
711 put_caching_control(caching_ctl);
712 return 0;
713 }
714
715 down_write(&fs_info->commit_root_sem);
716 atomic_inc(&caching_ctl->count);
717 list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
718 up_write(&fs_info->commit_root_sem);
719
720 btrfs_get_block_group(cache);
721
722 btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
723
724 return ret;
725 }
726
727 /*
728 * return the block group that starts at or after bytenr
729 */
730 static struct btrfs_block_group_cache *
731 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
732 {
733 struct btrfs_block_group_cache *cache;
734
735 cache = block_group_cache_tree_search(info, bytenr, 0);
736
737 return cache;
738 }
739
740 /*
741 * return the block group that contains the given bytenr
742 */
743 struct btrfs_block_group_cache *btrfs_lookup_block_group(
744 struct btrfs_fs_info *info,
745 u64 bytenr)
746 {
747 struct btrfs_block_group_cache *cache;
748
749 cache = block_group_cache_tree_search(info, bytenr, 1);
750
751 return cache;
752 }
753
754 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
755 u64 flags)
756 {
757 struct list_head *head = &info->space_info;
758 struct btrfs_space_info *found;
759
760 flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
761
762 rcu_read_lock();
763 list_for_each_entry_rcu(found, head, list) {
764 if (found->flags & flags) {
765 rcu_read_unlock();
766 return found;
767 }
768 }
769 rcu_read_unlock();
770 return NULL;
771 }
772
773 /*
774 * after adding space to the filesystem, we need to clear the full flags
775 * on all the space infos.
776 */
777 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
778 {
779 struct list_head *head = &info->space_info;
780 struct btrfs_space_info *found;
781
782 rcu_read_lock();
783 list_for_each_entry_rcu(found, head, list)
784 found->full = 0;
785 rcu_read_unlock();
786 }
787
788 /* simple helper to search for an existing data extent at a given offset */
789 int btrfs_lookup_data_extent(struct btrfs_root *root, u64 start, u64 len)
790 {
791 int ret;
792 struct btrfs_key key;
793 struct btrfs_path *path;
794
795 path = btrfs_alloc_path();
796 if (!path)
797 return -ENOMEM;
798
799 key.objectid = start;
800 key.offset = len;
801 key.type = BTRFS_EXTENT_ITEM_KEY;
802 ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
803 0, 0);
804 btrfs_free_path(path);
805 return ret;
806 }
807
808 /*
809 * helper function to lookup reference count and flags of a tree block.
810 *
811 * the head node for delayed ref is used to store the sum of all the
812 * reference count modifications queued up in the rbtree. the head
813 * node may also store the extent flags to set. This way you can check
814 * to see what the reference count and extent flags would be if all of
815 * the delayed refs are not processed.
816 */
817 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
818 struct btrfs_root *root, u64 bytenr,
819 u64 offset, int metadata, u64 *refs, u64 *flags)
820 {
821 struct btrfs_delayed_ref_head *head;
822 struct btrfs_delayed_ref_root *delayed_refs;
823 struct btrfs_path *path;
824 struct btrfs_extent_item *ei;
825 struct extent_buffer *leaf;
826 struct btrfs_key key;
827 u32 item_size;
828 u64 num_refs;
829 u64 extent_flags;
830 int ret;
831
832 /*
833 * If we don't have skinny metadata, don't bother doing anything
834 * different
835 */
836 if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA)) {
837 offset = root->nodesize;
838 metadata = 0;
839 }
840
841 path = btrfs_alloc_path();
842 if (!path)
843 return -ENOMEM;
844
845 if (!trans) {
846 path->skip_locking = 1;
847 path->search_commit_root = 1;
848 }
849
850 search_again:
851 key.objectid = bytenr;
852 key.offset = offset;
853 if (metadata)
854 key.type = BTRFS_METADATA_ITEM_KEY;
855 else
856 key.type = BTRFS_EXTENT_ITEM_KEY;
857
858 ret = btrfs_search_slot(trans, root->fs_info->extent_root,
859 &key, path, 0, 0);
860 if (ret < 0)
861 goto out_free;
862
863 if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
864 if (path->slots[0]) {
865 path->slots[0]--;
866 btrfs_item_key_to_cpu(path->nodes[0], &key,
867 path->slots[0]);
868 if (key.objectid == bytenr &&
869 key.type == BTRFS_EXTENT_ITEM_KEY &&
870 key.offset == root->nodesize)
871 ret = 0;
872 }
873 }
874
875 if (ret == 0) {
876 leaf = path->nodes[0];
877 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
878 if (item_size >= sizeof(*ei)) {
879 ei = btrfs_item_ptr(leaf, path->slots[0],
880 struct btrfs_extent_item);
881 num_refs = btrfs_extent_refs(leaf, ei);
882 extent_flags = btrfs_extent_flags(leaf, ei);
883 } else {
884 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
885 struct btrfs_extent_item_v0 *ei0;
886 BUG_ON(item_size != sizeof(*ei0));
887 ei0 = btrfs_item_ptr(leaf, path->slots[0],
888 struct btrfs_extent_item_v0);
889 num_refs = btrfs_extent_refs_v0(leaf, ei0);
890 /* FIXME: this isn't correct for data */
891 extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
892 #else
893 BUG();
894 #endif
895 }
896 BUG_ON(num_refs == 0);
897 } else {
898 num_refs = 0;
899 extent_flags = 0;
900 ret = 0;
901 }
902
903 if (!trans)
904 goto out;
905
906 delayed_refs = &trans->transaction->delayed_refs;
907 spin_lock(&delayed_refs->lock);
908 head = btrfs_find_delayed_ref_head(trans, bytenr);
909 if (head) {
910 if (!mutex_trylock(&head->mutex)) {
911 atomic_inc(&head->node.refs);
912 spin_unlock(&delayed_refs->lock);
913
914 btrfs_release_path(path);
915
916 /*
917 * Mutex was contended, block until it's released and try
918 * again
919 */
920 mutex_lock(&head->mutex);
921 mutex_unlock(&head->mutex);
922 btrfs_put_delayed_ref(&head->node);
923 goto search_again;
924 }
925 spin_lock(&head->lock);
926 if (head->extent_op && head->extent_op->update_flags)
927 extent_flags |= head->extent_op->flags_to_set;
928 else
929 BUG_ON(num_refs == 0);
930
931 num_refs += head->node.ref_mod;
932 spin_unlock(&head->lock);
933 mutex_unlock(&head->mutex);
934 }
935 spin_unlock(&delayed_refs->lock);
936 out:
937 WARN_ON(num_refs == 0);
938 if (refs)
939 *refs = num_refs;
940 if (flags)
941 *flags = extent_flags;
942 out_free:
943 btrfs_free_path(path);
944 return ret;
945 }
946
947 /*
948 * Back reference rules. Back refs have three main goals:
949 *
950 * 1) differentiate between all holders of references to an extent so that
951 * when a reference is dropped we can make sure it was a valid reference
952 * before freeing the extent.
953 *
954 * 2) Provide enough information to quickly find the holders of an extent
955 * if we notice a given block is corrupted or bad.
956 *
957 * 3) Make it easy to migrate blocks for FS shrinking or storage pool
958 * maintenance. This is actually the same as #2, but with a slightly
959 * different use case.
960 *
961 * There are two kinds of back refs. The implicit back refs is optimized
962 * for pointers in non-shared tree blocks. For a given pointer in a block,
963 * back refs of this kind provide information about the block's owner tree
964 * and the pointer's key. These information allow us to find the block by
965 * b-tree searching. The full back refs is for pointers in tree blocks not
966 * referenced by their owner trees. The location of tree block is recorded
967 * in the back refs. Actually the full back refs is generic, and can be
968 * used in all cases the implicit back refs is used. The major shortcoming
969 * of the full back refs is its overhead. Every time a tree block gets
970 * COWed, we have to update back refs entry for all pointers in it.
971 *
972 * For a newly allocated tree block, we use implicit back refs for
973 * pointers in it. This means most tree related operations only involve
974 * implicit back refs. For a tree block created in old transaction, the
975 * only way to drop a reference to it is COW it. So we can detect the
976 * event that tree block loses its owner tree's reference and do the
977 * back refs conversion.
978 *
979 * When a tree block is COWed through a tree, there are four cases:
980 *
981 * The reference count of the block is one and the tree is the block's
982 * owner tree. Nothing to do in this case.
983 *
984 * The reference count of the block is one and the tree is not the
985 * block's owner tree. In this case, full back refs is used for pointers
986 * in the block. Remove these full back refs, add implicit back refs for
987 * every pointers in the new block.
988 *
989 * The reference count of the block is greater than one and the tree is
990 * the block's owner tree. In this case, implicit back refs is used for
991 * pointers in the block. Add full back refs for every pointers in the
992 * block, increase lower level extents' reference counts. The original
993 * implicit back refs are entailed to the new block.
994 *
995 * The reference count of the block is greater than one and the tree is
996 * not the block's owner tree. Add implicit back refs for every pointer in
997 * the new block, increase lower level extents' reference count.
998 *
999 * Back Reference Key composing:
1000 *
1001 * The key objectid corresponds to the first byte in the extent,
1002 * The key type is used to differentiate between types of back refs.
1003 * There are different meanings of the key offset for different types
1004 * of back refs.
1005 *
1006 * File extents can be referenced by:
1007 *
1008 * - multiple snapshots, subvolumes, or different generations in one subvol
1009 * - different files inside a single subvolume
1010 * - different offsets inside a file (bookend extents in file.c)
1011 *
1012 * The extent ref structure for the implicit back refs has fields for:
1013 *
1014 * - Objectid of the subvolume root
1015 * - objectid of the file holding the reference
1016 * - original offset in the file
1017 * - how many bookend extents
1018 *
1019 * The key offset for the implicit back refs is hash of the first
1020 * three fields.
1021 *
1022 * The extent ref structure for the full back refs has field for:
1023 *
1024 * - number of pointers in the tree leaf
1025 *
1026 * The key offset for the implicit back refs is the first byte of
1027 * the tree leaf
1028 *
1029 * When a file extent is allocated, The implicit back refs is used.
1030 * the fields are filled in:
1031 *
1032 * (root_key.objectid, inode objectid, offset in file, 1)
1033 *
1034 * When a file extent is removed file truncation, we find the
1035 * corresponding implicit back refs and check the following fields:
1036 *
1037 * (btrfs_header_owner(leaf), inode objectid, offset in file)
1038 *
1039 * Btree extents can be referenced by:
1040 *
1041 * - Different subvolumes
1042 *
1043 * Both the implicit back refs and the full back refs for tree blocks
1044 * only consist of key. The key offset for the implicit back refs is
1045 * objectid of block's owner tree. The key offset for the full back refs
1046 * is the first byte of parent block.
1047 *
1048 * When implicit back refs is used, information about the lowest key and
1049 * level of the tree block are required. These information are stored in
1050 * tree block info structure.
1051 */
1052
1053 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1054 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
1055 struct btrfs_root *root,
1056 struct btrfs_path *path,
1057 u64 owner, u32 extra_size)
1058 {
1059 struct btrfs_extent_item *item;
1060 struct btrfs_extent_item_v0 *ei0;
1061 struct btrfs_extent_ref_v0 *ref0;
1062 struct btrfs_tree_block_info *bi;
1063 struct extent_buffer *leaf;
1064 struct btrfs_key key;
1065 struct btrfs_key found_key;
1066 u32 new_size = sizeof(*item);
1067 u64 refs;
1068 int ret;
1069
1070 leaf = path->nodes[0];
1071 BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
1072
1073 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1074 ei0 = btrfs_item_ptr(leaf, path->slots[0],
1075 struct btrfs_extent_item_v0);
1076 refs = btrfs_extent_refs_v0(leaf, ei0);
1077
1078 if (owner == (u64)-1) {
1079 while (1) {
1080 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1081 ret = btrfs_next_leaf(root, path);
1082 if (ret < 0)
1083 return ret;
1084 BUG_ON(ret > 0); /* Corruption */
1085 leaf = path->nodes[0];
1086 }
1087 btrfs_item_key_to_cpu(leaf, &found_key,
1088 path->slots[0]);
1089 BUG_ON(key.objectid != found_key.objectid);
1090 if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
1091 path->slots[0]++;
1092 continue;
1093 }
1094 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1095 struct btrfs_extent_ref_v0);
1096 owner = btrfs_ref_objectid_v0(leaf, ref0);
1097 break;
1098 }
1099 }
1100 btrfs_release_path(path);
1101
1102 if (owner < BTRFS_FIRST_FREE_OBJECTID)
1103 new_size += sizeof(*bi);
1104
1105 new_size -= sizeof(*ei0);
1106 ret = btrfs_search_slot(trans, root, &key, path,
1107 new_size + extra_size, 1);
1108 if (ret < 0)
1109 return ret;
1110 BUG_ON(ret); /* Corruption */
1111
1112 btrfs_extend_item(root, path, new_size);
1113
1114 leaf = path->nodes[0];
1115 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1116 btrfs_set_extent_refs(leaf, item, refs);
1117 /* FIXME: get real generation */
1118 btrfs_set_extent_generation(leaf, item, 0);
1119 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1120 btrfs_set_extent_flags(leaf, item,
1121 BTRFS_EXTENT_FLAG_TREE_BLOCK |
1122 BTRFS_BLOCK_FLAG_FULL_BACKREF);
1123 bi = (struct btrfs_tree_block_info *)(item + 1);
1124 /* FIXME: get first key of the block */
1125 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1126 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1127 } else {
1128 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1129 }
1130 btrfs_mark_buffer_dirty(leaf);
1131 return 0;
1132 }
1133 #endif
1134
1135 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1136 {
1137 u32 high_crc = ~(u32)0;
1138 u32 low_crc = ~(u32)0;
1139 __le64 lenum;
1140
1141 lenum = cpu_to_le64(root_objectid);
1142 high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
1143 lenum = cpu_to_le64(owner);
1144 low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1145 lenum = cpu_to_le64(offset);
1146 low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1147
1148 return ((u64)high_crc << 31) ^ (u64)low_crc;
1149 }
1150
1151 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1152 struct btrfs_extent_data_ref *ref)
1153 {
1154 return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1155 btrfs_extent_data_ref_objectid(leaf, ref),
1156 btrfs_extent_data_ref_offset(leaf, ref));
1157 }
1158
1159 static int match_extent_data_ref(struct extent_buffer *leaf,
1160 struct btrfs_extent_data_ref *ref,
1161 u64 root_objectid, u64 owner, u64 offset)
1162 {
1163 if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1164 btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1165 btrfs_extent_data_ref_offset(leaf, ref) != offset)
1166 return 0;
1167 return 1;
1168 }
1169
1170 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1171 struct btrfs_root *root,
1172 struct btrfs_path *path,
1173 u64 bytenr, u64 parent,
1174 u64 root_objectid,
1175 u64 owner, u64 offset)
1176 {
1177 struct btrfs_key key;
1178 struct btrfs_extent_data_ref *ref;
1179 struct extent_buffer *leaf;
1180 u32 nritems;
1181 int ret;
1182 int recow;
1183 int err = -ENOENT;
1184
1185 key.objectid = bytenr;
1186 if (parent) {
1187 key.type = BTRFS_SHARED_DATA_REF_KEY;
1188 key.offset = parent;
1189 } else {
1190 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1191 key.offset = hash_extent_data_ref(root_objectid,
1192 owner, offset);
1193 }
1194 again:
1195 recow = 0;
1196 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1197 if (ret < 0) {
1198 err = ret;
1199 goto fail;
1200 }
1201
1202 if (parent) {
1203 if (!ret)
1204 return 0;
1205 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1206 key.type = BTRFS_EXTENT_REF_V0_KEY;
1207 btrfs_release_path(path);
1208 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1209 if (ret < 0) {
1210 err = ret;
1211 goto fail;
1212 }
1213 if (!ret)
1214 return 0;
1215 #endif
1216 goto fail;
1217 }
1218
1219 leaf = path->nodes[0];
1220 nritems = btrfs_header_nritems(leaf);
1221 while (1) {
1222 if (path->slots[0] >= nritems) {
1223 ret = btrfs_next_leaf(root, path);
1224 if (ret < 0)
1225 err = ret;
1226 if (ret)
1227 goto fail;
1228
1229 leaf = path->nodes[0];
1230 nritems = btrfs_header_nritems(leaf);
1231 recow = 1;
1232 }
1233
1234 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1235 if (key.objectid != bytenr ||
1236 key.type != BTRFS_EXTENT_DATA_REF_KEY)
1237 goto fail;
1238
1239 ref = btrfs_item_ptr(leaf, path->slots[0],
1240 struct btrfs_extent_data_ref);
1241
1242 if (match_extent_data_ref(leaf, ref, root_objectid,
1243 owner, offset)) {
1244 if (recow) {
1245 btrfs_release_path(path);
1246 goto again;
1247 }
1248 err = 0;
1249 break;
1250 }
1251 path->slots[0]++;
1252 }
1253 fail:
1254 return err;
1255 }
1256
1257 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1258 struct btrfs_root *root,
1259 struct btrfs_path *path,
1260 u64 bytenr, u64 parent,
1261 u64 root_objectid, u64 owner,
1262 u64 offset, int refs_to_add)
1263 {
1264 struct btrfs_key key;
1265 struct extent_buffer *leaf;
1266 u32 size;
1267 u32 num_refs;
1268 int ret;
1269
1270 key.objectid = bytenr;
1271 if (parent) {
1272 key.type = BTRFS_SHARED_DATA_REF_KEY;
1273 key.offset = parent;
1274 size = sizeof(struct btrfs_shared_data_ref);
1275 } else {
1276 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1277 key.offset = hash_extent_data_ref(root_objectid,
1278 owner, offset);
1279 size = sizeof(struct btrfs_extent_data_ref);
1280 }
1281
1282 ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1283 if (ret && ret != -EEXIST)
1284 goto fail;
1285
1286 leaf = path->nodes[0];
1287 if (parent) {
1288 struct btrfs_shared_data_ref *ref;
1289 ref = btrfs_item_ptr(leaf, path->slots[0],
1290 struct btrfs_shared_data_ref);
1291 if (ret == 0) {
1292 btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1293 } else {
1294 num_refs = btrfs_shared_data_ref_count(leaf, ref);
1295 num_refs += refs_to_add;
1296 btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1297 }
1298 } else {
1299 struct btrfs_extent_data_ref *ref;
1300 while (ret == -EEXIST) {
1301 ref = btrfs_item_ptr(leaf, path->slots[0],
1302 struct btrfs_extent_data_ref);
1303 if (match_extent_data_ref(leaf, ref, root_objectid,
1304 owner, offset))
1305 break;
1306 btrfs_release_path(path);
1307 key.offset++;
1308 ret = btrfs_insert_empty_item(trans, root, path, &key,
1309 size);
1310 if (ret && ret != -EEXIST)
1311 goto fail;
1312
1313 leaf = path->nodes[0];
1314 }
1315 ref = btrfs_item_ptr(leaf, path->slots[0],
1316 struct btrfs_extent_data_ref);
1317 if (ret == 0) {
1318 btrfs_set_extent_data_ref_root(leaf, ref,
1319 root_objectid);
1320 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1321 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1322 btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1323 } else {
1324 num_refs = btrfs_extent_data_ref_count(leaf, ref);
1325 num_refs += refs_to_add;
1326 btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1327 }
1328 }
1329 btrfs_mark_buffer_dirty(leaf);
1330 ret = 0;
1331 fail:
1332 btrfs_release_path(path);
1333 return ret;
1334 }
1335
1336 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1337 struct btrfs_root *root,
1338 struct btrfs_path *path,
1339 int refs_to_drop, int *last_ref)
1340 {
1341 struct btrfs_key key;
1342 struct btrfs_extent_data_ref *ref1 = NULL;
1343 struct btrfs_shared_data_ref *ref2 = NULL;
1344 struct extent_buffer *leaf;
1345 u32 num_refs = 0;
1346 int ret = 0;
1347
1348 leaf = path->nodes[0];
1349 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1350
1351 if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1352 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1353 struct btrfs_extent_data_ref);
1354 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1355 } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1356 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1357 struct btrfs_shared_data_ref);
1358 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1359 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1360 } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1361 struct btrfs_extent_ref_v0 *ref0;
1362 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1363 struct btrfs_extent_ref_v0);
1364 num_refs = btrfs_ref_count_v0(leaf, ref0);
1365 #endif
1366 } else {
1367 BUG();
1368 }
1369
1370 BUG_ON(num_refs < refs_to_drop);
1371 num_refs -= refs_to_drop;
1372
1373 if (num_refs == 0) {
1374 ret = btrfs_del_item(trans, root, path);
1375 *last_ref = 1;
1376 } else {
1377 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1378 btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1379 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1380 btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1381 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1382 else {
1383 struct btrfs_extent_ref_v0 *ref0;
1384 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1385 struct btrfs_extent_ref_v0);
1386 btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1387 }
1388 #endif
1389 btrfs_mark_buffer_dirty(leaf);
1390 }
1391 return ret;
1392 }
1393
1394 static noinline u32 extent_data_ref_count(struct btrfs_path *path,
1395 struct btrfs_extent_inline_ref *iref)
1396 {
1397 struct btrfs_key key;
1398 struct extent_buffer *leaf;
1399 struct btrfs_extent_data_ref *ref1;
1400 struct btrfs_shared_data_ref *ref2;
1401 u32 num_refs = 0;
1402
1403 leaf = path->nodes[0];
1404 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1405 if (iref) {
1406 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1407 BTRFS_EXTENT_DATA_REF_KEY) {
1408 ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1409 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1410 } else {
1411 ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1412 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1413 }
1414 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1415 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1416 struct btrfs_extent_data_ref);
1417 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1418 } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1419 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1420 struct btrfs_shared_data_ref);
1421 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1422 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1423 } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1424 struct btrfs_extent_ref_v0 *ref0;
1425 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1426 struct btrfs_extent_ref_v0);
1427 num_refs = btrfs_ref_count_v0(leaf, ref0);
1428 #endif
1429 } else {
1430 WARN_ON(1);
1431 }
1432 return num_refs;
1433 }
1434
1435 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1436 struct btrfs_root *root,
1437 struct btrfs_path *path,
1438 u64 bytenr, u64 parent,
1439 u64 root_objectid)
1440 {
1441 struct btrfs_key key;
1442 int ret;
1443
1444 key.objectid = bytenr;
1445 if (parent) {
1446 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1447 key.offset = parent;
1448 } else {
1449 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1450 key.offset = root_objectid;
1451 }
1452
1453 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1454 if (ret > 0)
1455 ret = -ENOENT;
1456 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1457 if (ret == -ENOENT && parent) {
1458 btrfs_release_path(path);
1459 key.type = BTRFS_EXTENT_REF_V0_KEY;
1460 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1461 if (ret > 0)
1462 ret = -ENOENT;
1463 }
1464 #endif
1465 return ret;
1466 }
1467
1468 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1469 struct btrfs_root *root,
1470 struct btrfs_path *path,
1471 u64 bytenr, u64 parent,
1472 u64 root_objectid)
1473 {
1474 struct btrfs_key key;
1475 int ret;
1476
1477 key.objectid = bytenr;
1478 if (parent) {
1479 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1480 key.offset = parent;
1481 } else {
1482 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1483 key.offset = root_objectid;
1484 }
1485
1486 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1487 btrfs_release_path(path);
1488 return ret;
1489 }
1490
1491 static inline int extent_ref_type(u64 parent, u64 owner)
1492 {
1493 int type;
1494 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1495 if (parent > 0)
1496 type = BTRFS_SHARED_BLOCK_REF_KEY;
1497 else
1498 type = BTRFS_TREE_BLOCK_REF_KEY;
1499 } else {
1500 if (parent > 0)
1501 type = BTRFS_SHARED_DATA_REF_KEY;
1502 else
1503 type = BTRFS_EXTENT_DATA_REF_KEY;
1504 }
1505 return type;
1506 }
1507
1508 static int find_next_key(struct btrfs_path *path, int level,
1509 struct btrfs_key *key)
1510
1511 {
1512 for (; level < BTRFS_MAX_LEVEL; level++) {
1513 if (!path->nodes[level])
1514 break;
1515 if (path->slots[level] + 1 >=
1516 btrfs_header_nritems(path->nodes[level]))
1517 continue;
1518 if (level == 0)
1519 btrfs_item_key_to_cpu(path->nodes[level], key,
1520 path->slots[level] + 1);
1521 else
1522 btrfs_node_key_to_cpu(path->nodes[level], key,
1523 path->slots[level] + 1);
1524 return 0;
1525 }
1526 return 1;
1527 }
1528
1529 /*
1530 * look for inline back ref. if back ref is found, *ref_ret is set
1531 * to the address of inline back ref, and 0 is returned.
1532 *
1533 * if back ref isn't found, *ref_ret is set to the address where it
1534 * should be inserted, and -ENOENT is returned.
1535 *
1536 * if insert is true and there are too many inline back refs, the path
1537 * points to the extent item, and -EAGAIN is returned.
1538 *
1539 * NOTE: inline back refs are ordered in the same way that back ref
1540 * items in the tree are ordered.
1541 */
1542 static noinline_for_stack
1543 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1544 struct btrfs_root *root,
1545 struct btrfs_path *path,
1546 struct btrfs_extent_inline_ref **ref_ret,
1547 u64 bytenr, u64 num_bytes,
1548 u64 parent, u64 root_objectid,
1549 u64 owner, u64 offset, int insert)
1550 {
1551 struct btrfs_key key;
1552 struct extent_buffer *leaf;
1553 struct btrfs_extent_item *ei;
1554 struct btrfs_extent_inline_ref *iref;
1555 u64 flags;
1556 u64 item_size;
1557 unsigned long ptr;
1558 unsigned long end;
1559 int extra_size;
1560 int type;
1561 int want;
1562 int ret;
1563 int err = 0;
1564 bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
1565 SKINNY_METADATA);
1566
1567 key.objectid = bytenr;
1568 key.type = BTRFS_EXTENT_ITEM_KEY;
1569 key.offset = num_bytes;
1570
1571 want = extent_ref_type(parent, owner);
1572 if (insert) {
1573 extra_size = btrfs_extent_inline_ref_size(want);
1574 path->keep_locks = 1;
1575 } else
1576 extra_size = -1;
1577
1578 /*
1579 * Owner is our parent level, so we can just add one to get the level
1580 * for the block we are interested in.
1581 */
1582 if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1583 key.type = BTRFS_METADATA_ITEM_KEY;
1584 key.offset = owner;
1585 }
1586
1587 again:
1588 ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1589 if (ret < 0) {
1590 err = ret;
1591 goto out;
1592 }
1593
1594 /*
1595 * We may be a newly converted file system which still has the old fat
1596 * extent entries for metadata, so try and see if we have one of those.
1597 */
1598 if (ret > 0 && skinny_metadata) {
1599 skinny_metadata = false;
1600 if (path->slots[0]) {
1601 path->slots[0]--;
1602 btrfs_item_key_to_cpu(path->nodes[0], &key,
1603 path->slots[0]);
1604 if (key.objectid == bytenr &&
1605 key.type == BTRFS_EXTENT_ITEM_KEY &&
1606 key.offset == num_bytes)
1607 ret = 0;
1608 }
1609 if (ret) {
1610 key.objectid = bytenr;
1611 key.type = BTRFS_EXTENT_ITEM_KEY;
1612 key.offset = num_bytes;
1613 btrfs_release_path(path);
1614 goto again;
1615 }
1616 }
1617
1618 if (ret && !insert) {
1619 err = -ENOENT;
1620 goto out;
1621 } else if (WARN_ON(ret)) {
1622 err = -EIO;
1623 goto out;
1624 }
1625
1626 leaf = path->nodes[0];
1627 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1628 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1629 if (item_size < sizeof(*ei)) {
1630 if (!insert) {
1631 err = -ENOENT;
1632 goto out;
1633 }
1634 ret = convert_extent_item_v0(trans, root, path, owner,
1635 extra_size);
1636 if (ret < 0) {
1637 err = ret;
1638 goto out;
1639 }
1640 leaf = path->nodes[0];
1641 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1642 }
1643 #endif
1644 BUG_ON(item_size < sizeof(*ei));
1645
1646 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1647 flags = btrfs_extent_flags(leaf, ei);
1648
1649 ptr = (unsigned long)(ei + 1);
1650 end = (unsigned long)ei + item_size;
1651
1652 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1653 ptr += sizeof(struct btrfs_tree_block_info);
1654 BUG_ON(ptr > end);
1655 }
1656
1657 err = -ENOENT;
1658 while (1) {
1659 if (ptr >= end) {
1660 WARN_ON(ptr > end);
1661 break;
1662 }
1663 iref = (struct btrfs_extent_inline_ref *)ptr;
1664 type = btrfs_extent_inline_ref_type(leaf, iref);
1665 if (want < type)
1666 break;
1667 if (want > type) {
1668 ptr += btrfs_extent_inline_ref_size(type);
1669 continue;
1670 }
1671
1672 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1673 struct btrfs_extent_data_ref *dref;
1674 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1675 if (match_extent_data_ref(leaf, dref, root_objectid,
1676 owner, offset)) {
1677 err = 0;
1678 break;
1679 }
1680 if (hash_extent_data_ref_item(leaf, dref) <
1681 hash_extent_data_ref(root_objectid, owner, offset))
1682 break;
1683 } else {
1684 u64 ref_offset;
1685 ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1686 if (parent > 0) {
1687 if (parent == ref_offset) {
1688 err = 0;
1689 break;
1690 }
1691 if (ref_offset < parent)
1692 break;
1693 } else {
1694 if (root_objectid == ref_offset) {
1695 err = 0;
1696 break;
1697 }
1698 if (ref_offset < root_objectid)
1699 break;
1700 }
1701 }
1702 ptr += btrfs_extent_inline_ref_size(type);
1703 }
1704 if (err == -ENOENT && insert) {
1705 if (item_size + extra_size >=
1706 BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1707 err = -EAGAIN;
1708 goto out;
1709 }
1710 /*
1711 * To add new inline back ref, we have to make sure
1712 * there is no corresponding back ref item.
1713 * For simplicity, we just do not add new inline back
1714 * ref if there is any kind of item for this block
1715 */
1716 if (find_next_key(path, 0, &key) == 0 &&
1717 key.objectid == bytenr &&
1718 key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1719 err = -EAGAIN;
1720 goto out;
1721 }
1722 }
1723 *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1724 out:
1725 if (insert) {
1726 path->keep_locks = 0;
1727 btrfs_unlock_up_safe(path, 1);
1728 }
1729 return err;
1730 }
1731
1732 /*
1733 * helper to add new inline back ref
1734 */
1735 static noinline_for_stack
1736 void setup_inline_extent_backref(struct btrfs_root *root,
1737 struct btrfs_path *path,
1738 struct btrfs_extent_inline_ref *iref,
1739 u64 parent, u64 root_objectid,
1740 u64 owner, u64 offset, int refs_to_add,
1741 struct btrfs_delayed_extent_op *extent_op)
1742 {
1743 struct extent_buffer *leaf;
1744 struct btrfs_extent_item *ei;
1745 unsigned long ptr;
1746 unsigned long end;
1747 unsigned long item_offset;
1748 u64 refs;
1749 int size;
1750 int type;
1751
1752 leaf = path->nodes[0];
1753 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1754 item_offset = (unsigned long)iref - (unsigned long)ei;
1755
1756 type = extent_ref_type(parent, owner);
1757 size = btrfs_extent_inline_ref_size(type);
1758
1759 btrfs_extend_item(root, path, size);
1760
1761 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1762 refs = btrfs_extent_refs(leaf, ei);
1763 refs += refs_to_add;
1764 btrfs_set_extent_refs(leaf, ei, refs);
1765 if (extent_op)
1766 __run_delayed_extent_op(extent_op, leaf, ei);
1767
1768 ptr = (unsigned long)ei + item_offset;
1769 end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1770 if (ptr < end - size)
1771 memmove_extent_buffer(leaf, ptr + size, ptr,
1772 end - size - ptr);
1773
1774 iref = (struct btrfs_extent_inline_ref *)ptr;
1775 btrfs_set_extent_inline_ref_type(leaf, iref, type);
1776 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1777 struct btrfs_extent_data_ref *dref;
1778 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1779 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1780 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1781 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1782 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1783 } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1784 struct btrfs_shared_data_ref *sref;
1785 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1786 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1787 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1788 } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1789 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1790 } else {
1791 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1792 }
1793 btrfs_mark_buffer_dirty(leaf);
1794 }
1795
1796 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1797 struct btrfs_root *root,
1798 struct btrfs_path *path,
1799 struct btrfs_extent_inline_ref **ref_ret,
1800 u64 bytenr, u64 num_bytes, u64 parent,
1801 u64 root_objectid, u64 owner, u64 offset)
1802 {
1803 int ret;
1804
1805 ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1806 bytenr, num_bytes, parent,
1807 root_objectid, owner, offset, 0);
1808 if (ret != -ENOENT)
1809 return ret;
1810
1811 btrfs_release_path(path);
1812 *ref_ret = NULL;
1813
1814 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1815 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1816 root_objectid);
1817 } else {
1818 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1819 root_objectid, owner, offset);
1820 }
1821 return ret;
1822 }
1823
1824 /*
1825 * helper to update/remove inline back ref
1826 */
1827 static noinline_for_stack
1828 void update_inline_extent_backref(struct btrfs_root *root,
1829 struct btrfs_path *path,
1830 struct btrfs_extent_inline_ref *iref,
1831 int refs_to_mod,
1832 struct btrfs_delayed_extent_op *extent_op,
1833 int *last_ref)
1834 {
1835 struct extent_buffer *leaf;
1836 struct btrfs_extent_item *ei;
1837 struct btrfs_extent_data_ref *dref = NULL;
1838 struct btrfs_shared_data_ref *sref = NULL;
1839 unsigned long ptr;
1840 unsigned long end;
1841 u32 item_size;
1842 int size;
1843 int type;
1844 u64 refs;
1845
1846 leaf = path->nodes[0];
1847 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1848 refs = btrfs_extent_refs(leaf, ei);
1849 WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1850 refs += refs_to_mod;
1851 btrfs_set_extent_refs(leaf, ei, refs);
1852 if (extent_op)
1853 __run_delayed_extent_op(extent_op, leaf, ei);
1854
1855 type = btrfs_extent_inline_ref_type(leaf, iref);
1856
1857 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1858 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1859 refs = btrfs_extent_data_ref_count(leaf, dref);
1860 } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1861 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1862 refs = btrfs_shared_data_ref_count(leaf, sref);
1863 } else {
1864 refs = 1;
1865 BUG_ON(refs_to_mod != -1);
1866 }
1867
1868 BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1869 refs += refs_to_mod;
1870
1871 if (refs > 0) {
1872 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1873 btrfs_set_extent_data_ref_count(leaf, dref, refs);
1874 else
1875 btrfs_set_shared_data_ref_count(leaf, sref, refs);
1876 } else {
1877 *last_ref = 1;
1878 size = btrfs_extent_inline_ref_size(type);
1879 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1880 ptr = (unsigned long)iref;
1881 end = (unsigned long)ei + item_size;
1882 if (ptr + size < end)
1883 memmove_extent_buffer(leaf, ptr, ptr + size,
1884 end - ptr - size);
1885 item_size -= size;
1886 btrfs_truncate_item(root, path, item_size, 1);
1887 }
1888 btrfs_mark_buffer_dirty(leaf);
1889 }
1890
1891 static noinline_for_stack
1892 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1893 struct btrfs_root *root,
1894 struct btrfs_path *path,
1895 u64 bytenr, u64 num_bytes, u64 parent,
1896 u64 root_objectid, u64 owner,
1897 u64 offset, int refs_to_add,
1898 struct btrfs_delayed_extent_op *extent_op)
1899 {
1900 struct btrfs_extent_inline_ref *iref;
1901 int ret;
1902
1903 ret = lookup_inline_extent_backref(trans, root, path, &iref,
1904 bytenr, num_bytes, parent,
1905 root_objectid, owner, offset, 1);
1906 if (ret == 0) {
1907 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1908 update_inline_extent_backref(root, path, iref,
1909 refs_to_add, extent_op, NULL);
1910 } else if (ret == -ENOENT) {
1911 setup_inline_extent_backref(root, path, iref, parent,
1912 root_objectid, owner, offset,
1913 refs_to_add, extent_op);
1914 ret = 0;
1915 }
1916 return ret;
1917 }
1918
1919 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1920 struct btrfs_root *root,
1921 struct btrfs_path *path,
1922 u64 bytenr, u64 parent, u64 root_objectid,
1923 u64 owner, u64 offset, int refs_to_add)
1924 {
1925 int ret;
1926 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1927 BUG_ON(refs_to_add != 1);
1928 ret = insert_tree_block_ref(trans, root, path, bytenr,
1929 parent, root_objectid);
1930 } else {
1931 ret = insert_extent_data_ref(trans, root, path, bytenr,
1932 parent, root_objectid,
1933 owner, offset, refs_to_add);
1934 }
1935 return ret;
1936 }
1937
1938 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1939 struct btrfs_root *root,
1940 struct btrfs_path *path,
1941 struct btrfs_extent_inline_ref *iref,
1942 int refs_to_drop, int is_data, int *last_ref)
1943 {
1944 int ret = 0;
1945
1946 BUG_ON(!is_data && refs_to_drop != 1);
1947 if (iref) {
1948 update_inline_extent_backref(root, path, iref,
1949 -refs_to_drop, NULL, last_ref);
1950 } else if (is_data) {
1951 ret = remove_extent_data_ref(trans, root, path, refs_to_drop,
1952 last_ref);
1953 } else {
1954 *last_ref = 1;
1955 ret = btrfs_del_item(trans, root, path);
1956 }
1957 return ret;
1958 }
1959
1960 #define in_range(b, first, len) ((b) >= (first) && (b) < (first) + (len))
1961 static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
1962 u64 *discarded_bytes)
1963 {
1964 int j, ret = 0;
1965 u64 bytes_left, end;
1966 u64 aligned_start = ALIGN(start, 1 << 9);
1967
1968 if (WARN_ON(start != aligned_start)) {
1969 len -= aligned_start - start;
1970 len = round_down(len, 1 << 9);
1971 start = aligned_start;
1972 }
1973
1974 *discarded_bytes = 0;
1975
1976 if (!len)
1977 return 0;
1978
1979 end = start + len;
1980 bytes_left = len;
1981
1982 /* Skip any superblocks on this device. */
1983 for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
1984 u64 sb_start = btrfs_sb_offset(j);
1985 u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
1986 u64 size = sb_start - start;
1987
1988 if (!in_range(sb_start, start, bytes_left) &&
1989 !in_range(sb_end, start, bytes_left) &&
1990 !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
1991 continue;
1992
1993 /*
1994 * Superblock spans beginning of range. Adjust start and
1995 * try again.
1996 */
1997 if (sb_start <= start) {
1998 start += sb_end - start;
1999 if (start > end) {
2000 bytes_left = 0;
2001 break;
2002 }
2003 bytes_left = end - start;
2004 continue;
2005 }
2006
2007 if (size) {
2008 ret = blkdev_issue_discard(bdev, start >> 9, size >> 9,
2009 GFP_NOFS, 0);
2010 if (!ret)
2011 *discarded_bytes += size;
2012 else if (ret != -EOPNOTSUPP)
2013 return ret;
2014 }
2015
2016 start = sb_end;
2017 if (start > end) {
2018 bytes_left = 0;
2019 break;
2020 }
2021 bytes_left = end - start;
2022 }
2023
2024 if (bytes_left) {
2025 ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9,
2026 GFP_NOFS, 0);
2027 if (!ret)
2028 *discarded_bytes += bytes_left;
2029 }
2030 return ret;
2031 }
2032
2033 int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
2034 u64 num_bytes, u64 *actual_bytes)
2035 {
2036 int ret;
2037 u64 discarded_bytes = 0;
2038 struct btrfs_bio *bbio = NULL;
2039
2040
2041 /*
2042 * Avoid races with device replace and make sure our bbio has devices
2043 * associated to its stripes that don't go away while we are discarding.
2044 */
2045 btrfs_bio_counter_inc_blocked(root->fs_info);
2046 /* Tell the block device(s) that the sectors can be discarded */
2047 ret = btrfs_map_block(root->fs_info, REQ_OP_DISCARD,
2048 bytenr, &num_bytes, &bbio, 0);
2049 /* Error condition is -ENOMEM */
2050 if (!ret) {
2051 struct btrfs_bio_stripe *stripe = bbio->stripes;
2052 int i;
2053
2054
2055 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
2056 u64 bytes;
2057 if (!stripe->dev->can_discard)
2058 continue;
2059
2060 ret = btrfs_issue_discard(stripe->dev->bdev,
2061 stripe->physical,
2062 stripe->length,
2063 &bytes);
2064 if (!ret)
2065 discarded_bytes += bytes;
2066 else if (ret != -EOPNOTSUPP)
2067 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
2068
2069 /*
2070 * Just in case we get back EOPNOTSUPP for some reason,
2071 * just ignore the return value so we don't screw up
2072 * people calling discard_extent.
2073 */
2074 ret = 0;
2075 }
2076 btrfs_put_bbio(bbio);
2077 }
2078 btrfs_bio_counter_dec(root->fs_info);
2079
2080 if (actual_bytes)
2081 *actual_bytes = discarded_bytes;
2082
2083
2084 if (ret == -EOPNOTSUPP)
2085 ret = 0;
2086 return ret;
2087 }
2088
2089 /* Can return -ENOMEM */
2090 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2091 struct btrfs_root *root,
2092 u64 bytenr, u64 num_bytes, u64 parent,
2093 u64 root_objectid, u64 owner, u64 offset)
2094 {
2095 int ret;
2096 struct btrfs_fs_info *fs_info = root->fs_info;
2097
2098 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
2099 root_objectid == BTRFS_TREE_LOG_OBJECTID);
2100
2101 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
2102 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
2103 num_bytes,
2104 parent, root_objectid, (int)owner,
2105 BTRFS_ADD_DELAYED_REF, NULL);
2106 } else {
2107 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
2108 num_bytes, parent, root_objectid,
2109 owner, offset, 0,
2110 BTRFS_ADD_DELAYED_REF, NULL);
2111 }
2112 return ret;
2113 }
2114
2115 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2116 struct btrfs_root *root,
2117 struct btrfs_delayed_ref_node *node,
2118 u64 parent, u64 root_objectid,
2119 u64 owner, u64 offset, int refs_to_add,
2120 struct btrfs_delayed_extent_op *extent_op)
2121 {
2122 struct btrfs_fs_info *fs_info = root->fs_info;
2123 struct btrfs_path *path;
2124 struct extent_buffer *leaf;
2125 struct btrfs_extent_item *item;
2126 struct btrfs_key key;
2127 u64 bytenr = node->bytenr;
2128 u64 num_bytes = node->num_bytes;
2129 u64 refs;
2130 int ret;
2131
2132 path = btrfs_alloc_path();
2133 if (!path)
2134 return -ENOMEM;
2135
2136 path->reada = READA_FORWARD;
2137 path->leave_spinning = 1;
2138 /* this will setup the path even if it fails to insert the back ref */
2139 ret = insert_inline_extent_backref(trans, fs_info->extent_root, path,
2140 bytenr, num_bytes, parent,
2141 root_objectid, owner, offset,
2142 refs_to_add, extent_op);
2143 if ((ret < 0 && ret != -EAGAIN) || !ret)
2144 goto out;
2145
2146 /*
2147 * Ok we had -EAGAIN which means we didn't have space to insert and
2148 * inline extent ref, so just update the reference count and add a
2149 * normal backref.
2150 */
2151 leaf = path->nodes[0];
2152 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2153 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2154 refs = btrfs_extent_refs(leaf, item);
2155 btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2156 if (extent_op)
2157 __run_delayed_extent_op(extent_op, leaf, item);
2158
2159 btrfs_mark_buffer_dirty(leaf);
2160 btrfs_release_path(path);
2161
2162 path->reada = READA_FORWARD;
2163 path->leave_spinning = 1;
2164 /* now insert the actual backref */
2165 ret = insert_extent_backref(trans, root->fs_info->extent_root,
2166 path, bytenr, parent, root_objectid,
2167 owner, offset, refs_to_add);
2168 if (ret)
2169 btrfs_abort_transaction(trans, ret);
2170 out:
2171 btrfs_free_path(path);
2172 return ret;
2173 }
2174
2175 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2176 struct btrfs_root *root,
2177 struct btrfs_delayed_ref_node *node,
2178 struct btrfs_delayed_extent_op *extent_op,
2179 int insert_reserved)
2180 {
2181 int ret = 0;
2182 struct btrfs_delayed_data_ref *ref;
2183 struct btrfs_key ins;
2184 u64 parent = 0;
2185 u64 ref_root = 0;
2186 u64 flags = 0;
2187
2188 ins.objectid = node->bytenr;
2189 ins.offset = node->num_bytes;
2190 ins.type = BTRFS_EXTENT_ITEM_KEY;
2191
2192 ref = btrfs_delayed_node_to_data_ref(node);
2193 trace_run_delayed_data_ref(root->fs_info, node, ref, node->action);
2194
2195 if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2196 parent = ref->parent;
2197 ref_root = ref->root;
2198
2199 if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2200 if (extent_op)
2201 flags |= extent_op->flags_to_set;
2202 ret = alloc_reserved_file_extent(trans, root,
2203 parent, ref_root, flags,
2204 ref->objectid, ref->offset,
2205 &ins, node->ref_mod);
2206 } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2207 ret = __btrfs_inc_extent_ref(trans, root, node, parent,
2208 ref_root, ref->objectid,
2209 ref->offset, node->ref_mod,
2210 extent_op);
2211 } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2212 ret = __btrfs_free_extent(trans, root, node, parent,
2213 ref_root, ref->objectid,
2214 ref->offset, node->ref_mod,
2215 extent_op);
2216 } else {
2217 BUG();
2218 }
2219 return ret;
2220 }
2221
2222 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2223 struct extent_buffer *leaf,
2224 struct btrfs_extent_item *ei)
2225 {
2226 u64 flags = btrfs_extent_flags(leaf, ei);
2227 if (extent_op->update_flags) {
2228 flags |= extent_op->flags_to_set;
2229 btrfs_set_extent_flags(leaf, ei, flags);
2230 }
2231
2232 if (extent_op->update_key) {
2233 struct btrfs_tree_block_info *bi;
2234 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2235 bi = (struct btrfs_tree_block_info *)(ei + 1);
2236 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2237 }
2238 }
2239
2240 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2241 struct btrfs_root *root,
2242 struct btrfs_delayed_ref_node *node,
2243 struct btrfs_delayed_extent_op *extent_op)
2244 {
2245 struct btrfs_key key;
2246 struct btrfs_path *path;
2247 struct btrfs_extent_item *ei;
2248 struct extent_buffer *leaf;
2249 u32 item_size;
2250 int ret;
2251 int err = 0;
2252 int metadata = !extent_op->is_data;
2253
2254 if (trans->aborted)
2255 return 0;
2256
2257 if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2258 metadata = 0;
2259
2260 path = btrfs_alloc_path();
2261 if (!path)
2262 return -ENOMEM;
2263
2264 key.objectid = node->bytenr;
2265
2266 if (metadata) {
2267 key.type = BTRFS_METADATA_ITEM_KEY;
2268 key.offset = extent_op->level;
2269 } else {
2270 key.type = BTRFS_EXTENT_ITEM_KEY;
2271 key.offset = node->num_bytes;
2272 }
2273
2274 again:
2275 path->reada = READA_FORWARD;
2276 path->leave_spinning = 1;
2277 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2278 path, 0, 1);
2279 if (ret < 0) {
2280 err = ret;
2281 goto out;
2282 }
2283 if (ret > 0) {
2284 if (metadata) {
2285 if (path->slots[0] > 0) {
2286 path->slots[0]--;
2287 btrfs_item_key_to_cpu(path->nodes[0], &key,
2288 path->slots[0]);
2289 if (key.objectid == node->bytenr &&
2290 key.type == BTRFS_EXTENT_ITEM_KEY &&
2291 key.offset == node->num_bytes)
2292 ret = 0;
2293 }
2294 if (ret > 0) {
2295 btrfs_release_path(path);
2296 metadata = 0;
2297
2298 key.objectid = node->bytenr;
2299 key.offset = node->num_bytes;
2300 key.type = BTRFS_EXTENT_ITEM_KEY;
2301 goto again;
2302 }
2303 } else {
2304 err = -EIO;
2305 goto out;
2306 }
2307 }
2308
2309 leaf = path->nodes[0];
2310 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2311 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2312 if (item_size < sizeof(*ei)) {
2313 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2314 path, (u64)-1, 0);
2315 if (ret < 0) {
2316 err = ret;
2317 goto out;
2318 }
2319 leaf = path->nodes[0];
2320 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2321 }
2322 #endif
2323 BUG_ON(item_size < sizeof(*ei));
2324 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2325 __run_delayed_extent_op(extent_op, leaf, ei);
2326
2327 btrfs_mark_buffer_dirty(leaf);
2328 out:
2329 btrfs_free_path(path);
2330 return err;
2331 }
2332
2333 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2334 struct btrfs_root *root,
2335 struct btrfs_delayed_ref_node *node,
2336 struct btrfs_delayed_extent_op *extent_op,
2337 int insert_reserved)
2338 {
2339 int ret = 0;
2340 struct btrfs_delayed_tree_ref *ref;
2341 struct btrfs_key ins;
2342 u64 parent = 0;
2343 u64 ref_root = 0;
2344 bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
2345 SKINNY_METADATA);
2346
2347 ref = btrfs_delayed_node_to_tree_ref(node);
2348 trace_run_delayed_tree_ref(root->fs_info, node, ref, node->action);
2349
2350 if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2351 parent = ref->parent;
2352 ref_root = ref->root;
2353
2354 ins.objectid = node->bytenr;
2355 if (skinny_metadata) {
2356 ins.offset = ref->level;
2357 ins.type = BTRFS_METADATA_ITEM_KEY;
2358 } else {
2359 ins.offset = node->num_bytes;
2360 ins.type = BTRFS_EXTENT_ITEM_KEY;
2361 }
2362
2363 BUG_ON(node->ref_mod != 1);
2364 if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2365 BUG_ON(!extent_op || !extent_op->update_flags);
2366 ret = alloc_reserved_tree_block(trans, root,
2367 parent, ref_root,
2368 extent_op->flags_to_set,
2369 &extent_op->key,
2370 ref->level, &ins);
2371 } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2372 ret = __btrfs_inc_extent_ref(trans, root, node,
2373 parent, ref_root,
2374 ref->level, 0, 1,
2375 extent_op);
2376 } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2377 ret = __btrfs_free_extent(trans, root, node,
2378 parent, ref_root,
2379 ref->level, 0, 1, extent_op);
2380 } else {
2381 BUG();
2382 }
2383 return ret;
2384 }
2385
2386 /* helper function to actually process a single delayed ref entry */
2387 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2388 struct btrfs_root *root,
2389 struct btrfs_delayed_ref_node *node,
2390 struct btrfs_delayed_extent_op *extent_op,
2391 int insert_reserved)
2392 {
2393 int ret = 0;
2394
2395 if (trans->aborted) {
2396 if (insert_reserved)
2397 btrfs_pin_extent(root, node->bytenr,
2398 node->num_bytes, 1);
2399 return 0;
2400 }
2401
2402 if (btrfs_delayed_ref_is_head(node)) {
2403 struct btrfs_delayed_ref_head *head;
2404 /*
2405 * we've hit the end of the chain and we were supposed
2406 * to insert this extent into the tree. But, it got
2407 * deleted before we ever needed to insert it, so all
2408 * we have to do is clean up the accounting
2409 */
2410 BUG_ON(extent_op);
2411 head = btrfs_delayed_node_to_head(node);
2412 trace_run_delayed_ref_head(root->fs_info, node, head,
2413 node->action);
2414
2415 if (insert_reserved) {
2416 btrfs_pin_extent(root, node->bytenr,
2417 node->num_bytes, 1);
2418 if (head->is_data) {
2419 ret = btrfs_del_csums(trans, root,
2420 node->bytenr,
2421 node->num_bytes);
2422 }
2423 }
2424
2425 /* Also free its reserved qgroup space */
2426 btrfs_qgroup_free_delayed_ref(root->fs_info,
2427 head->qgroup_ref_root,
2428 head->qgroup_reserved);
2429 return ret;
2430 }
2431
2432 if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2433 node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2434 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2435 insert_reserved);
2436 else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2437 node->type == BTRFS_SHARED_DATA_REF_KEY)
2438 ret = run_delayed_data_ref(trans, root, node, extent_op,
2439 insert_reserved);
2440 else
2441 BUG();
2442 return ret;
2443 }
2444
2445 static inline struct btrfs_delayed_ref_node *
2446 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2447 {
2448 struct btrfs_delayed_ref_node *ref;
2449
2450 if (list_empty(&head->ref_list))
2451 return NULL;
2452
2453 /*
2454 * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
2455 * This is to prevent a ref count from going down to zero, which deletes
2456 * the extent item from the extent tree, when there still are references
2457 * to add, which would fail because they would not find the extent item.
2458 */
2459 list_for_each_entry(ref, &head->ref_list, list) {
2460 if (ref->action == BTRFS_ADD_DELAYED_REF)
2461 return ref;
2462 }
2463
2464 return list_entry(head->ref_list.next, struct btrfs_delayed_ref_node,
2465 list);
2466 }
2467
2468 /*
2469 * Returns 0 on success or if called with an already aborted transaction.
2470 * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2471 */
2472 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2473 struct btrfs_root *root,
2474 unsigned long nr)
2475 {
2476 struct btrfs_delayed_ref_root *delayed_refs;
2477 struct btrfs_delayed_ref_node *ref;
2478 struct btrfs_delayed_ref_head *locked_ref = NULL;
2479 struct btrfs_delayed_extent_op *extent_op;
2480 struct btrfs_fs_info *fs_info = root->fs_info;
2481 ktime_t start = ktime_get();
2482 int ret;
2483 unsigned long count = 0;
2484 unsigned long actual_count = 0;
2485 int must_insert_reserved = 0;
2486
2487 delayed_refs = &trans->transaction->delayed_refs;
2488 while (1) {
2489 if (!locked_ref) {
2490 if (count >= nr)
2491 break;
2492
2493 spin_lock(&delayed_refs->lock);
2494 locked_ref = btrfs_select_ref_head(trans);
2495 if (!locked_ref) {
2496 spin_unlock(&delayed_refs->lock);
2497 break;
2498 }
2499
2500 /* grab the lock that says we are going to process
2501 * all the refs for this head */
2502 ret = btrfs_delayed_ref_lock(trans, locked_ref);
2503 spin_unlock(&delayed_refs->lock);
2504 /*
2505 * we may have dropped the spin lock to get the head
2506 * mutex lock, and that might have given someone else
2507 * time to free the head. If that's true, it has been
2508 * removed from our list and we can move on.
2509 */
2510 if (ret == -EAGAIN) {
2511 locked_ref = NULL;
2512 count++;
2513 continue;
2514 }
2515 }
2516
2517 /*
2518 * We need to try and merge add/drops of the same ref since we
2519 * can run into issues with relocate dropping the implicit ref
2520 * and then it being added back again before the drop can
2521 * finish. If we merged anything we need to re-loop so we can
2522 * get a good ref.
2523 * Or we can get node references of the same type that weren't
2524 * merged when created due to bumps in the tree mod seq, and
2525 * we need to merge them to prevent adding an inline extent
2526 * backref before dropping it (triggering a BUG_ON at
2527 * insert_inline_extent_backref()).
2528 */
2529 spin_lock(&locked_ref->lock);
2530 btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
2531 locked_ref);
2532
2533 /*
2534 * locked_ref is the head node, so we have to go one
2535 * node back for any delayed ref updates
2536 */
2537 ref = select_delayed_ref(locked_ref);
2538
2539 if (ref && ref->seq &&
2540 btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2541 spin_unlock(&locked_ref->lock);
2542 btrfs_delayed_ref_unlock(locked_ref);
2543 spin_lock(&delayed_refs->lock);
2544 locked_ref->processing = 0;
2545 delayed_refs->num_heads_ready++;
2546 spin_unlock(&delayed_refs->lock);
2547 locked_ref = NULL;
2548 cond_resched();
2549 count++;
2550 continue;
2551 }
2552
2553 /*
2554 * record the must insert reserved flag before we
2555 * drop the spin lock.
2556 */
2557 must_insert_reserved = locked_ref->must_insert_reserved;
2558 locked_ref->must_insert_reserved = 0;
2559
2560 extent_op = locked_ref->extent_op;
2561 locked_ref->extent_op = NULL;
2562
2563 if (!ref) {
2564
2565
2566 /* All delayed refs have been processed, Go ahead
2567 * and send the head node to run_one_delayed_ref,
2568 * so that any accounting fixes can happen
2569 */
2570 ref = &locked_ref->node;
2571
2572 if (extent_op && must_insert_reserved) {
2573 btrfs_free_delayed_extent_op(extent_op);
2574 extent_op = NULL;
2575 }
2576
2577 if (extent_op) {
2578 spin_unlock(&locked_ref->lock);
2579 ret = run_delayed_extent_op(trans, root,
2580 ref, extent_op);
2581 btrfs_free_delayed_extent_op(extent_op);
2582
2583 if (ret) {
2584 /*
2585 * Need to reset must_insert_reserved if
2586 * there was an error so the abort stuff
2587 * can cleanup the reserved space
2588 * properly.
2589 */
2590 if (must_insert_reserved)
2591 locked_ref->must_insert_reserved = 1;
2592 locked_ref->processing = 0;
2593 btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2594 btrfs_delayed_ref_unlock(locked_ref);
2595 return ret;
2596 }
2597 continue;
2598 }
2599
2600 /*
2601 * Need to drop our head ref lock and re-acquire the
2602 * delayed ref lock and then re-check to make sure
2603 * nobody got added.
2604 */
2605 spin_unlock(&locked_ref->lock);
2606 spin_lock(&delayed_refs->lock);
2607 spin_lock(&locked_ref->lock);
2608 if (!list_empty(&locked_ref->ref_list) ||
2609 locked_ref->extent_op) {
2610 spin_unlock(&locked_ref->lock);
2611 spin_unlock(&delayed_refs->lock);
2612 continue;
2613 }
2614 ref->in_tree = 0;
2615 delayed_refs->num_heads--;
2616 rb_erase(&locked_ref->href_node,
2617 &delayed_refs->href_root);
2618 spin_unlock(&delayed_refs->lock);
2619 } else {
2620 actual_count++;
2621 ref->in_tree = 0;
2622 list_del(&ref->list);
2623 }
2624 atomic_dec(&delayed_refs->num_entries);
2625
2626 if (!btrfs_delayed_ref_is_head(ref)) {
2627 /*
2628 * when we play the delayed ref, also correct the
2629 * ref_mod on head
2630 */
2631 switch (ref->action) {
2632 case BTRFS_ADD_DELAYED_REF:
2633 case BTRFS_ADD_DELAYED_EXTENT:
2634 locked_ref->node.ref_mod -= ref->ref_mod;
2635 break;
2636 case BTRFS_DROP_DELAYED_REF:
2637 locked_ref->node.ref_mod += ref->ref_mod;
2638 break;
2639 default:
2640 WARN_ON(1);
2641 }
2642 }
2643 spin_unlock(&locked_ref->lock);
2644
2645 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2646 must_insert_reserved);
2647
2648 btrfs_free_delayed_extent_op(extent_op);
2649 if (ret) {
2650 locked_ref->processing = 0;
2651 btrfs_delayed_ref_unlock(locked_ref);
2652 btrfs_put_delayed_ref(ref);
2653 btrfs_debug(fs_info, "run_one_delayed_ref returned %d", ret);
2654 return ret;
2655 }
2656
2657 /*
2658 * If this node is a head, that means all the refs in this head
2659 * have been dealt with, and we will pick the next head to deal
2660 * with, so we must unlock the head and drop it from the cluster
2661 * list before we release it.
2662 */
2663 if (btrfs_delayed_ref_is_head(ref)) {
2664 if (locked_ref->is_data &&
2665 locked_ref->total_ref_mod < 0) {
2666 spin_lock(&delayed_refs->lock);
2667 delayed_refs->pending_csums -= ref->num_bytes;
2668 spin_unlock(&delayed_refs->lock);
2669 }
2670 btrfs_delayed_ref_unlock(locked_ref);
2671 locked_ref = NULL;
2672 }
2673 btrfs_put_delayed_ref(ref);
2674 count++;
2675 cond_resched();
2676 }
2677
2678 /*
2679 * We don't want to include ref heads since we can have empty ref heads
2680 * and those will drastically skew our runtime down since we just do
2681 * accounting, no actual extent tree updates.
2682 */
2683 if (actual_count > 0) {
2684 u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2685 u64 avg;
2686
2687 /*
2688 * We weigh the current average higher than our current runtime
2689 * to avoid large swings in the average.
2690 */
2691 spin_lock(&delayed_refs->lock);
2692 avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2693 fs_info->avg_delayed_ref_runtime = avg >> 2; /* div by 4 */
2694 spin_unlock(&delayed_refs->lock);
2695 }
2696 return 0;
2697 }
2698
2699 #ifdef SCRAMBLE_DELAYED_REFS
2700 /*
2701 * Normally delayed refs get processed in ascending bytenr order. This
2702 * correlates in most cases to the order added. To expose dependencies on this
2703 * order, we start to process the tree in the middle instead of the beginning
2704 */
2705 static u64 find_middle(struct rb_root *root)
2706 {
2707 struct rb_node *n = root->rb_node;
2708 struct btrfs_delayed_ref_node *entry;
2709 int alt = 1;
2710 u64 middle;
2711 u64 first = 0, last = 0;
2712
2713 n = rb_first(root);
2714 if (n) {
2715 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2716 first = entry->bytenr;
2717 }
2718 n = rb_last(root);
2719 if (n) {
2720 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2721 last = entry->bytenr;
2722 }
2723 n = root->rb_node;
2724
2725 while (n) {
2726 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2727 WARN_ON(!entry->in_tree);
2728
2729 middle = entry->bytenr;
2730
2731 if (alt)
2732 n = n->rb_left;
2733 else
2734 n = n->rb_right;
2735
2736 alt = 1 - alt;
2737 }
2738 return middle;
2739 }
2740 #endif
2741
2742 static inline u64 heads_to_leaves(struct btrfs_root *root, u64 heads)
2743 {
2744 u64 num_bytes;
2745
2746 num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2747 sizeof(struct btrfs_extent_inline_ref));
2748 if (!btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2749 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2750
2751 /*
2752 * We don't ever fill up leaves all the way so multiply by 2 just to be
2753 * closer to what we're really going to want to use.
2754 */
2755 return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(root));
2756 }
2757
2758 /*
2759 * Takes the number of bytes to be csumm'ed and figures out how many leaves it
2760 * would require to store the csums for that many bytes.
2761 */
2762 u64 btrfs_csum_bytes_to_leaves(struct btrfs_root *root, u64 csum_bytes)
2763 {
2764 u64 csum_size;
2765 u64 num_csums_per_leaf;
2766 u64 num_csums;
2767
2768 csum_size = BTRFS_MAX_ITEM_SIZE(root);
2769 num_csums_per_leaf = div64_u64(csum_size,
2770 (u64)btrfs_super_csum_size(root->fs_info->super_copy));
2771 num_csums = div64_u64(csum_bytes, root->sectorsize);
2772 num_csums += num_csums_per_leaf - 1;
2773 num_csums = div64_u64(num_csums, num_csums_per_leaf);
2774 return num_csums;
2775 }
2776
2777 int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans,
2778 struct btrfs_root *root)
2779 {
2780 struct btrfs_block_rsv *global_rsv;
2781 u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2782 u64 csum_bytes = trans->transaction->delayed_refs.pending_csums;
2783 u64 num_dirty_bgs = trans->transaction->num_dirty_bgs;
2784 u64 num_bytes, num_dirty_bgs_bytes;
2785 int ret = 0;
2786
2787 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
2788 num_heads = heads_to_leaves(root, num_heads);
2789 if (num_heads > 1)
2790 num_bytes += (num_heads - 1) * root->nodesize;
2791 num_bytes <<= 1;
2792 num_bytes += btrfs_csum_bytes_to_leaves(root, csum_bytes) * root->nodesize;
2793 num_dirty_bgs_bytes = btrfs_calc_trans_metadata_size(root,
2794 num_dirty_bgs);
2795 global_rsv = &root->fs_info->global_block_rsv;
2796
2797 /*
2798 * If we can't allocate any more chunks lets make sure we have _lots_ of
2799 * wiggle room since running delayed refs can create more delayed refs.
2800 */
2801 if (global_rsv->space_info->full) {
2802 num_dirty_bgs_bytes <<= 1;
2803 num_bytes <<= 1;
2804 }
2805
2806 spin_lock(&global_rsv->lock);
2807 if (global_rsv->reserved <= num_bytes + num_dirty_bgs_bytes)
2808 ret = 1;
2809 spin_unlock(&global_rsv->lock);
2810 return ret;
2811 }
2812
2813 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2814 struct btrfs_root *root)
2815 {
2816 struct btrfs_fs_info *fs_info = root->fs_info;
2817 u64 num_entries =
2818 atomic_read(&trans->transaction->delayed_refs.num_entries);
2819 u64 avg_runtime;
2820 u64 val;
2821
2822 smp_mb();
2823 avg_runtime = fs_info->avg_delayed_ref_runtime;
2824 val = num_entries * avg_runtime;
2825 if (num_entries * avg_runtime >= NSEC_PER_SEC)
2826 return 1;
2827 if (val >= NSEC_PER_SEC / 2)
2828 return 2;
2829
2830 return btrfs_check_space_for_delayed_refs(trans, root);
2831 }
2832
2833 struct async_delayed_refs {
2834 struct btrfs_root *root;
2835 u64 transid;
2836 int count;
2837 int error;
2838 int sync;
2839 struct completion wait;
2840 struct btrfs_work work;
2841 };
2842
2843 static void delayed_ref_async_start(struct btrfs_work *work)
2844 {
2845 struct async_delayed_refs *async;
2846 struct btrfs_trans_handle *trans;
2847 int ret;
2848
2849 async = container_of(work, struct async_delayed_refs, work);
2850
2851 /* if the commit is already started, we don't need to wait here */
2852 if (btrfs_transaction_blocked(async->root->fs_info))
2853 goto done;
2854
2855 trans = btrfs_join_transaction(async->root);
2856 if (IS_ERR(trans)) {
2857 async->error = PTR_ERR(trans);
2858 goto done;
2859 }
2860
2861 /*
2862 * trans->sync means that when we call end_transaction, we won't
2863 * wait on delayed refs
2864 */
2865 trans->sync = true;
2866
2867 /* Don't bother flushing if we got into a different transaction */
2868 if (trans->transid > async->transid)
2869 goto end;
2870
2871 ret = btrfs_run_delayed_refs(trans, async->root, async->count);
2872 if (ret)
2873 async->error = ret;
2874 end:
2875 ret = btrfs_end_transaction(trans, async->root);
2876 if (ret && !async->error)
2877 async->error = ret;
2878 done:
2879 if (async->sync)
2880 complete(&async->wait);
2881 else
2882 kfree(async);
2883 }
2884
2885 int btrfs_async_run_delayed_refs(struct btrfs_root *root,
2886 unsigned long count, u64 transid, int wait)
2887 {
2888 struct async_delayed_refs *async;
2889 int ret;
2890
2891 async = kmalloc(sizeof(*async), GFP_NOFS);
2892 if (!async)
2893 return -ENOMEM;
2894
2895 async->root = root->fs_info->tree_root;
2896 async->count = count;
2897 async->error = 0;
2898 async->transid = transid;
2899 if (wait)
2900 async->sync = 1;
2901 else
2902 async->sync = 0;
2903 init_completion(&async->wait);
2904
2905 btrfs_init_work(&async->work, btrfs_extent_refs_helper,
2906 delayed_ref_async_start, NULL, NULL);
2907
2908 btrfs_queue_work(root->fs_info->extent_workers, &async->work);
2909
2910 if (wait) {
2911 wait_for_completion(&async->wait);
2912 ret = async->error;
2913 kfree(async);
2914 return ret;
2915 }
2916 return 0;
2917 }
2918
2919 /*
2920 * this starts processing the delayed reference count updates and
2921 * extent insertions we have queued up so far. count can be
2922 * 0, which means to process everything in the tree at the start
2923 * of the run (but not newly added entries), or it can be some target
2924 * number you'd like to process.
2925 *
2926 * Returns 0 on success or if called with an aborted transaction
2927 * Returns <0 on error and aborts the transaction
2928 */
2929 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2930 struct btrfs_root *root, unsigned long count)
2931 {
2932 struct rb_node *node;
2933 struct btrfs_delayed_ref_root *delayed_refs;
2934 struct btrfs_delayed_ref_head *head;
2935 int ret;
2936 int run_all = count == (unsigned long)-1;
2937 bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
2938
2939 /* We'll clean this up in btrfs_cleanup_transaction */
2940 if (trans->aborted)
2941 return 0;
2942
2943 if (root->fs_info->creating_free_space_tree)
2944 return 0;
2945
2946 if (root == root->fs_info->extent_root)
2947 root = root->fs_info->tree_root;
2948
2949 delayed_refs = &trans->transaction->delayed_refs;
2950 if (count == 0)
2951 count = atomic_read(&delayed_refs->num_entries) * 2;
2952
2953 again:
2954 #ifdef SCRAMBLE_DELAYED_REFS
2955 delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2956 #endif
2957 trans->can_flush_pending_bgs = false;
2958 ret = __btrfs_run_delayed_refs(trans, root, count);
2959 if (ret < 0) {
2960 btrfs_abort_transaction(trans, ret);
2961 return ret;
2962 }
2963
2964 if (run_all) {
2965 if (!list_empty(&trans->new_bgs))
2966 btrfs_create_pending_block_groups(trans, root);
2967
2968 spin_lock(&delayed_refs->lock);
2969 node = rb_first(&delayed_refs->href_root);
2970 if (!node) {
2971 spin_unlock(&delayed_refs->lock);
2972 goto out;
2973 }
2974 count = (unsigned long)-1;
2975
2976 while (node) {
2977 head = rb_entry(node, struct btrfs_delayed_ref_head,
2978 href_node);
2979 if (btrfs_delayed_ref_is_head(&head->node)) {
2980 struct btrfs_delayed_ref_node *ref;
2981
2982 ref = &head->node;
2983 atomic_inc(&ref->refs);
2984
2985 spin_unlock(&delayed_refs->lock);
2986 /*
2987 * Mutex was contended, block until it's
2988 * released and try again
2989 */
2990 mutex_lock(&head->mutex);
2991 mutex_unlock(&head->mutex);
2992
2993 btrfs_put_delayed_ref(ref);
2994 cond_resched();
2995 goto again;
2996 } else {
2997 WARN_ON(1);
2998 }
2999 node = rb_next(node);
3000 }
3001 spin_unlock(&delayed_refs->lock);
3002 cond_resched();
3003 goto again;
3004 }
3005 out:
3006 assert_qgroups_uptodate(trans);
3007 trans->can_flush_pending_bgs = can_flush_pending_bgs;
3008 return 0;
3009 }
3010
3011 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
3012 struct btrfs_root *root,
3013 u64 bytenr, u64 num_bytes, u64 flags,
3014 int level, int is_data)
3015 {
3016 struct btrfs_delayed_extent_op *extent_op;
3017 int ret;
3018
3019 extent_op = btrfs_alloc_delayed_extent_op();
3020 if (!extent_op)
3021 return -ENOMEM;
3022
3023 extent_op->flags_to_set = flags;
3024 extent_op->update_flags = true;
3025 extent_op->update_key = false;
3026 extent_op->is_data = is_data ? true : false;
3027 extent_op->level = level;
3028
3029 ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
3030 num_bytes, extent_op);
3031 if (ret)
3032 btrfs_free_delayed_extent_op(extent_op);
3033 return ret;
3034 }
3035
3036 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
3037 struct btrfs_root *root,
3038 struct btrfs_path *path,
3039 u64 objectid, u64 offset, u64 bytenr)
3040 {
3041 struct btrfs_delayed_ref_head *head;
3042 struct btrfs_delayed_ref_node *ref;
3043 struct btrfs_delayed_data_ref *data_ref;
3044 struct btrfs_delayed_ref_root *delayed_refs;
3045 int ret = 0;
3046
3047 delayed_refs = &trans->transaction->delayed_refs;
3048 spin_lock(&delayed_refs->lock);
3049 head = btrfs_find_delayed_ref_head(trans, bytenr);
3050 if (!head) {
3051 spin_unlock(&delayed_refs->lock);
3052 return 0;
3053 }
3054
3055 if (!mutex_trylock(&head->mutex)) {
3056 atomic_inc(&head->node.refs);
3057 spin_unlock(&delayed_refs->lock);
3058
3059 btrfs_release_path(path);
3060
3061 /*
3062 * Mutex was contended, block until it's released and let
3063 * caller try again
3064 */
3065 mutex_lock(&head->mutex);
3066 mutex_unlock(&head->mutex);
3067 btrfs_put_delayed_ref(&head->node);
3068 return -EAGAIN;
3069 }
3070 spin_unlock(&delayed_refs->lock);
3071
3072 spin_lock(&head->lock);
3073 list_for_each_entry(ref, &head->ref_list, list) {
3074 /* If it's a shared ref we know a cross reference exists */
3075 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
3076 ret = 1;
3077 break;
3078 }
3079
3080 data_ref = btrfs_delayed_node_to_data_ref(ref);
3081
3082 /*
3083 * If our ref doesn't match the one we're currently looking at
3084 * then we have a cross reference.
3085 */
3086 if (data_ref->root != root->root_key.objectid ||
3087 data_ref->objectid != objectid ||
3088 data_ref->offset != offset) {
3089 ret = 1;
3090 break;
3091 }
3092 }
3093 spin_unlock(&head->lock);
3094 mutex_unlock(&head->mutex);
3095 return ret;
3096 }
3097
3098 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
3099 struct btrfs_root *root,
3100 struct btrfs_path *path,
3101 u64 objectid, u64 offset, u64 bytenr)
3102 {
3103 struct btrfs_root *extent_root = root->fs_info->extent_root;
3104 struct extent_buffer *leaf;
3105 struct btrfs_extent_data_ref *ref;
3106 struct btrfs_extent_inline_ref *iref;
3107 struct btrfs_extent_item *ei;
3108 struct btrfs_key key;
3109 u32 item_size;
3110 int ret;
3111
3112 key.objectid = bytenr;
3113 key.offset = (u64)-1;
3114 key.type = BTRFS_EXTENT_ITEM_KEY;
3115
3116 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
3117 if (ret < 0)
3118 goto out;
3119 BUG_ON(ret == 0); /* Corruption */
3120
3121 ret = -ENOENT;
3122 if (path->slots[0] == 0)
3123 goto out;
3124
3125 path->slots[0]--;
3126 leaf = path->nodes[0];
3127 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3128
3129 if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
3130 goto out;
3131
3132 ret = 1;
3133 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
3134 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3135 if (item_size < sizeof(*ei)) {
3136 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3137 goto out;
3138 }
3139 #endif
3140 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
3141
3142 if (item_size != sizeof(*ei) +
3143 btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
3144 goto out;
3145
3146 if (btrfs_extent_generation(leaf, ei) <=
3147 btrfs_root_last_snapshot(&root->root_item))
3148 goto out;
3149
3150 iref = (struct btrfs_extent_inline_ref *)(ei + 1);
3151 if (btrfs_extent_inline_ref_type(leaf, iref) !=
3152 BTRFS_EXTENT_DATA_REF_KEY)
3153 goto out;
3154
3155 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
3156 if (btrfs_extent_refs(leaf, ei) !=
3157 btrfs_extent_data_ref_count(leaf, ref) ||
3158 btrfs_extent_data_ref_root(leaf, ref) !=
3159 root->root_key.objectid ||
3160 btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
3161 btrfs_extent_data_ref_offset(leaf, ref) != offset)
3162 goto out;
3163
3164 ret = 0;
3165 out:
3166 return ret;
3167 }
3168
3169 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
3170 struct btrfs_root *root,
3171 u64 objectid, u64 offset, u64 bytenr)
3172 {
3173 struct btrfs_path *path;
3174 int ret;
3175 int ret2;
3176
3177 path = btrfs_alloc_path();
3178 if (!path)
3179 return -ENOENT;
3180
3181 do {
3182 ret = check_committed_ref(trans, root, path, objectid,
3183 offset, bytenr);
3184 if (ret && ret != -ENOENT)
3185 goto out;
3186
3187 ret2 = check_delayed_ref(trans, root, path, objectid,
3188 offset, bytenr);
3189 } while (ret2 == -EAGAIN);
3190
3191 if (ret2 && ret2 != -ENOENT) {
3192 ret = ret2;
3193 goto out;
3194 }
3195
3196 if (ret != -ENOENT || ret2 != -ENOENT)
3197 ret = 0;
3198 out:
3199 btrfs_free_path(path);
3200 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3201 WARN_ON(ret > 0);
3202 return ret;
3203 }
3204
3205 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3206 struct btrfs_root *root,
3207 struct extent_buffer *buf,
3208 int full_backref, int inc)
3209 {
3210 u64 bytenr;
3211 u64 num_bytes;
3212 u64 parent;
3213 u64 ref_root;
3214 u32 nritems;
3215 struct btrfs_key key;
3216 struct btrfs_file_extent_item *fi;
3217 int i;
3218 int level;
3219 int ret = 0;
3220 int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
3221 u64, u64, u64, u64, u64, u64);
3222
3223
3224 if (btrfs_is_testing(root->fs_info))
3225 return 0;
3226
3227 ref_root = btrfs_header_owner(buf);
3228 nritems = btrfs_header_nritems(buf);
3229 level = btrfs_header_level(buf);
3230
3231 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
3232 return 0;
3233
3234 if (inc)
3235 process_func = btrfs_inc_extent_ref;
3236 else
3237 process_func = btrfs_free_extent;
3238
3239 if (full_backref)
3240 parent = buf->start;
3241 else
3242 parent = 0;
3243
3244 for (i = 0; i < nritems; i++) {
3245 if (level == 0) {
3246 btrfs_item_key_to_cpu(buf, &key, i);
3247 if (key.type != BTRFS_EXTENT_DATA_KEY)
3248 continue;
3249 fi = btrfs_item_ptr(buf, i,
3250 struct btrfs_file_extent_item);
3251 if (btrfs_file_extent_type(buf, fi) ==
3252 BTRFS_FILE_EXTENT_INLINE)
3253 continue;
3254 bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3255 if (bytenr == 0)
3256 continue;
3257
3258 num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3259 key.offset -= btrfs_file_extent_offset(buf, fi);
3260 ret = process_func(trans, root, bytenr, num_bytes,
3261 parent, ref_root, key.objectid,
3262 key.offset);
3263 if (ret)
3264 goto fail;
3265 } else {
3266 bytenr = btrfs_node_blockptr(buf, i);
3267 num_bytes = root->nodesize;
3268 ret = process_func(trans, root, bytenr, num_bytes,
3269 parent, ref_root, level - 1, 0);
3270 if (ret)
3271 goto fail;
3272 }
3273 }
3274 return 0;
3275 fail:
3276 return ret;
3277 }
3278
3279 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3280 struct extent_buffer *buf, int full_backref)
3281 {
3282 return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
3283 }
3284
3285 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3286 struct extent_buffer *buf, int full_backref)
3287 {
3288 return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
3289 }
3290
3291 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3292 struct btrfs_root *root,
3293 struct btrfs_path *path,
3294 struct btrfs_block_group_cache *cache)
3295 {
3296 int ret;
3297 struct btrfs_root *extent_root = root->fs_info->extent_root;
3298 unsigned long bi;
3299 struct extent_buffer *leaf;
3300
3301 ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3302 if (ret) {
3303 if (ret > 0)
3304 ret = -ENOENT;
3305 goto fail;
3306 }
3307
3308 leaf = path->nodes[0];
3309 bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3310 write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3311 btrfs_mark_buffer_dirty(leaf);
3312 fail:
3313 btrfs_release_path(path);
3314 return ret;
3315
3316 }
3317
3318 static struct btrfs_block_group_cache *
3319 next_block_group(struct btrfs_root *root,
3320 struct btrfs_block_group_cache *cache)
3321 {
3322 struct rb_node *node;
3323
3324 spin_lock(&root->fs_info->block_group_cache_lock);
3325
3326 /* If our block group was removed, we need a full search. */
3327 if (RB_EMPTY_NODE(&cache->cache_node)) {
3328 const u64 next_bytenr = cache->key.objectid + cache->key.offset;
3329
3330 spin_unlock(&root->fs_info->block_group_cache_lock);
3331 btrfs_put_block_group(cache);
3332 cache = btrfs_lookup_first_block_group(root->fs_info,
3333 next_bytenr);
3334 return cache;
3335 }
3336 node = rb_next(&cache->cache_node);
3337 btrfs_put_block_group(cache);
3338 if (node) {
3339 cache = rb_entry(node, struct btrfs_block_group_cache,
3340 cache_node);
3341 btrfs_get_block_group(cache);
3342 } else
3343 cache = NULL;
3344 spin_unlock(&root->fs_info->block_group_cache_lock);
3345 return cache;
3346 }
3347
3348 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3349 struct btrfs_trans_handle *trans,
3350 struct btrfs_path *path)
3351 {
3352 struct btrfs_root *root = block_group->fs_info->tree_root;
3353 struct inode *inode = NULL;
3354 u64 alloc_hint = 0;
3355 int dcs = BTRFS_DC_ERROR;
3356 u64 num_pages = 0;
3357 int retries = 0;
3358 int ret = 0;
3359
3360 /*
3361 * If this block group is smaller than 100 megs don't bother caching the
3362 * block group.
3363 */
3364 if (block_group->key.offset < (100 * SZ_1M)) {
3365 spin_lock(&block_group->lock);
3366 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3367 spin_unlock(&block_group->lock);
3368 return 0;
3369 }
3370
3371 if (trans->aborted)
3372 return 0;
3373 again:
3374 inode = lookup_free_space_inode(root, block_group, path);
3375 if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3376 ret = PTR_ERR(inode);
3377 btrfs_release_path(path);
3378 goto out;
3379 }
3380
3381 if (IS_ERR(inode)) {
3382 BUG_ON(retries);
3383 retries++;
3384
3385 if (block_group->ro)
3386 goto out_free;
3387
3388 ret = create_free_space_inode(root, trans, block_group, path);
3389 if (ret)
3390 goto out_free;
3391 goto again;
3392 }
3393
3394 /* We've already setup this transaction, go ahead and exit */
3395 if (block_group->cache_generation == trans->transid &&
3396 i_size_read(inode)) {
3397 dcs = BTRFS_DC_SETUP;
3398 goto out_put;
3399 }
3400
3401 /*
3402 * We want to set the generation to 0, that way if anything goes wrong
3403 * from here on out we know not to trust this cache when we load up next
3404 * time.
3405 */
3406 BTRFS_I(inode)->generation = 0;
3407 ret = btrfs_update_inode(trans, root, inode);
3408 if (ret) {
3409 /*
3410 * So theoretically we could recover from this, simply set the
3411 * super cache generation to 0 so we know to invalidate the
3412 * cache, but then we'd have to keep track of the block groups
3413 * that fail this way so we know we _have_ to reset this cache
3414 * before the next commit or risk reading stale cache. So to
3415 * limit our exposure to horrible edge cases lets just abort the
3416 * transaction, this only happens in really bad situations
3417 * anyway.
3418 */
3419 btrfs_abort_transaction(trans, ret);
3420 goto out_put;
3421 }
3422 WARN_ON(ret);
3423
3424 if (i_size_read(inode) > 0) {
3425 ret = btrfs_check_trunc_cache_free_space(root,
3426 &root->fs_info->global_block_rsv);
3427 if (ret)
3428 goto out_put;
3429
3430 ret = btrfs_truncate_free_space_cache(root, trans, NULL, inode);
3431 if (ret)
3432 goto out_put;
3433 }
3434
3435 spin_lock(&block_group->lock);
3436 if (block_group->cached != BTRFS_CACHE_FINISHED ||
3437 !btrfs_test_opt(root->fs_info, SPACE_CACHE)) {
3438 /*
3439 * don't bother trying to write stuff out _if_
3440 * a) we're not cached,
3441 * b) we're with nospace_cache mount option.
3442 */
3443 dcs = BTRFS_DC_WRITTEN;
3444 spin_unlock(&block_group->lock);
3445 goto out_put;
3446 }
3447 spin_unlock(&block_group->lock);
3448
3449 /*
3450 * We hit an ENOSPC when setting up the cache in this transaction, just
3451 * skip doing the setup, we've already cleared the cache so we're safe.
3452 */
3453 if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
3454 ret = -ENOSPC;
3455 goto out_put;
3456 }
3457
3458 /*
3459 * Try to preallocate enough space based on how big the block group is.
3460 * Keep in mind this has to include any pinned space which could end up
3461 * taking up quite a bit since it's not folded into the other space
3462 * cache.
3463 */
3464 num_pages = div_u64(block_group->key.offset, SZ_256M);
3465 if (!num_pages)
3466 num_pages = 1;
3467
3468 num_pages *= 16;
3469 num_pages *= PAGE_SIZE;
3470
3471 ret = btrfs_check_data_free_space(inode, 0, num_pages);
3472 if (ret)
3473 goto out_put;
3474
3475 ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3476 num_pages, num_pages,
3477 &alloc_hint);
3478 /*
3479 * Our cache requires contiguous chunks so that we don't modify a bunch
3480 * of metadata or split extents when writing the cache out, which means
3481 * we can enospc if we are heavily fragmented in addition to just normal
3482 * out of space conditions. So if we hit this just skip setting up any
3483 * other block groups for this transaction, maybe we'll unpin enough
3484 * space the next time around.
3485 */
3486 if (!ret)
3487 dcs = BTRFS_DC_SETUP;
3488 else if (ret == -ENOSPC)
3489 set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
3490
3491 out_put:
3492 iput(inode);
3493 out_free:
3494 btrfs_release_path(path);
3495 out:
3496 spin_lock(&block_group->lock);
3497 if (!ret && dcs == BTRFS_DC_SETUP)
3498 block_group->cache_generation = trans->transid;
3499 block_group->disk_cache_state = dcs;
3500 spin_unlock(&block_group->lock);
3501
3502 return ret;
3503 }
3504
3505 int btrfs_setup_space_cache(struct btrfs_trans_handle *trans,
3506 struct btrfs_root *root)
3507 {
3508 struct btrfs_block_group_cache *cache, *tmp;
3509 struct btrfs_transaction *cur_trans = trans->transaction;
3510 struct btrfs_path *path;
3511
3512 if (list_empty(&cur_trans->dirty_bgs) ||
3513 !btrfs_test_opt(root->fs_info, SPACE_CACHE))
3514 return 0;
3515
3516 path = btrfs_alloc_path();
3517 if (!path)
3518 return -ENOMEM;
3519
3520 /* Could add new block groups, use _safe just in case */
3521 list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
3522 dirty_list) {
3523 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3524 cache_save_setup(cache, trans, path);
3525 }
3526
3527 btrfs_free_path(path);
3528 return 0;
3529 }
3530
3531 /*
3532 * transaction commit does final block group cache writeback during a
3533 * critical section where nothing is allowed to change the FS. This is
3534 * required in order for the cache to actually match the block group,
3535 * but can introduce a lot of latency into the commit.
3536 *
3537 * So, btrfs_start_dirty_block_groups is here to kick off block group
3538 * cache IO. There's a chance we'll have to redo some of it if the
3539 * block group changes again during the commit, but it greatly reduces
3540 * the commit latency by getting rid of the easy block groups while
3541 * we're still allowing others to join the commit.
3542 */
3543 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans,
3544 struct btrfs_root *root)
3545 {
3546 struct btrfs_block_group_cache *cache;
3547 struct btrfs_transaction *cur_trans = trans->transaction;
3548 int ret = 0;
3549 int should_put;
3550 struct btrfs_path *path = NULL;
3551 LIST_HEAD(dirty);
3552 struct list_head *io = &cur_trans->io_bgs;
3553 int num_started = 0;
3554 int loops = 0;
3555
3556 spin_lock(&cur_trans->dirty_bgs_lock);
3557 if (list_empty(&cur_trans->dirty_bgs)) {
3558 spin_unlock(&cur_trans->dirty_bgs_lock);
3559 return 0;
3560 }
3561 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3562 spin_unlock(&cur_trans->dirty_bgs_lock);
3563
3564 again:
3565 /*
3566 * make sure all the block groups on our dirty list actually
3567 * exist
3568 */
3569 btrfs_create_pending_block_groups(trans, root);
3570
3571 if (!path) {
3572 path = btrfs_alloc_path();
3573 if (!path)
3574 return -ENOMEM;
3575 }
3576
3577 /*
3578 * cache_write_mutex is here only to save us from balance or automatic
3579 * removal of empty block groups deleting this block group while we are
3580 * writing out the cache
3581 */
3582 mutex_lock(&trans->transaction->cache_write_mutex);
3583 while (!list_empty(&dirty)) {
3584 cache = list_first_entry(&dirty,
3585 struct btrfs_block_group_cache,
3586 dirty_list);
3587 /*
3588 * this can happen if something re-dirties a block
3589 * group that is already under IO. Just wait for it to
3590 * finish and then do it all again
3591 */
3592 if (!list_empty(&cache->io_list)) {
3593 list_del_init(&cache->io_list);
3594 btrfs_wait_cache_io(root, trans, cache,
3595 &cache->io_ctl, path,
3596 cache->key.objectid);
3597 btrfs_put_block_group(cache);
3598 }
3599
3600
3601 /*
3602 * btrfs_wait_cache_io uses the cache->dirty_list to decide
3603 * if it should update the cache_state. Don't delete
3604 * until after we wait.
3605 *
3606 * Since we're not running in the commit critical section
3607 * we need the dirty_bgs_lock to protect from update_block_group
3608 */
3609 spin_lock(&cur_trans->dirty_bgs_lock);
3610 list_del_init(&cache->dirty_list);
3611 spin_unlock(&cur_trans->dirty_bgs_lock);
3612
3613 should_put = 1;
3614
3615 cache_save_setup(cache, trans, path);
3616
3617 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
3618 cache->io_ctl.inode = NULL;
3619 ret = btrfs_write_out_cache(root, trans, cache, path);
3620 if (ret == 0 && cache->io_ctl.inode) {
3621 num_started++;
3622 should_put = 0;
3623
3624 /*
3625 * the cache_write_mutex is protecting
3626 * the io_list
3627 */
3628 list_add_tail(&cache->io_list, io);
3629 } else {
3630 /*
3631 * if we failed to write the cache, the
3632 * generation will be bad and life goes on
3633 */
3634 ret = 0;
3635 }
3636 }
3637 if (!ret) {
3638 ret = write_one_cache_group(trans, root, path, cache);
3639 /*
3640 * Our block group might still be attached to the list
3641 * of new block groups in the transaction handle of some
3642 * other task (struct btrfs_trans_handle->new_bgs). This
3643 * means its block group item isn't yet in the extent
3644 * tree. If this happens ignore the error, as we will
3645 * try again later in the critical section of the
3646 * transaction commit.
3647 */
3648 if (ret == -ENOENT) {
3649 ret = 0;
3650 spin_lock(&cur_trans->dirty_bgs_lock);
3651 if (list_empty(&cache->dirty_list)) {
3652 list_add_tail(&cache->dirty_list,
3653 &cur_trans->dirty_bgs);
3654 btrfs_get_block_group(cache);
3655 }
3656 spin_unlock(&cur_trans->dirty_bgs_lock);
3657 } else if (ret) {
3658 btrfs_abort_transaction(trans, ret);
3659 }
3660 }
3661
3662 /* if its not on the io list, we need to put the block group */
3663 if (should_put)
3664 btrfs_put_block_group(cache);
3665
3666 if (ret)
3667 break;
3668
3669 /*
3670 * Avoid blocking other tasks for too long. It might even save
3671 * us from writing caches for block groups that are going to be
3672 * removed.
3673 */
3674 mutex_unlock(&trans->transaction->cache_write_mutex);
3675 mutex_lock(&trans->transaction->cache_write_mutex);
3676 }
3677 mutex_unlock(&trans->transaction->cache_write_mutex);
3678
3679 /*
3680 * go through delayed refs for all the stuff we've just kicked off
3681 * and then loop back (just once)
3682 */
3683 ret = btrfs_run_delayed_refs(trans, root, 0);
3684 if (!ret && loops == 0) {
3685 loops++;
3686 spin_lock(&cur_trans->dirty_bgs_lock);
3687 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3688 /*
3689 * dirty_bgs_lock protects us from concurrent block group
3690 * deletes too (not just cache_write_mutex).
3691 */
3692 if (!list_empty(&dirty)) {
3693 spin_unlock(&cur_trans->dirty_bgs_lock);
3694 goto again;
3695 }
3696 spin_unlock(&cur_trans->dirty_bgs_lock);
3697 } else if (ret < 0) {
3698 btrfs_cleanup_dirty_bgs(cur_trans, root);
3699 }
3700
3701 btrfs_free_path(path);
3702 return ret;
3703 }
3704
3705 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3706 struct btrfs_root *root)
3707 {
3708 struct btrfs_block_group_cache *cache;
3709 struct btrfs_transaction *cur_trans = trans->transaction;
3710 int ret = 0;
3711 int should_put;
3712 struct btrfs_path *path;
3713 struct list_head *io = &cur_trans->io_bgs;
3714 int num_started = 0;
3715
3716 path = btrfs_alloc_path();
3717 if (!path)
3718 return -ENOMEM;
3719
3720 /*
3721 * Even though we are in the critical section of the transaction commit,
3722 * we can still have concurrent tasks adding elements to this
3723 * transaction's list of dirty block groups. These tasks correspond to
3724 * endio free space workers started when writeback finishes for a
3725 * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
3726 * allocate new block groups as a result of COWing nodes of the root
3727 * tree when updating the free space inode. The writeback for the space
3728 * caches is triggered by an earlier call to
3729 * btrfs_start_dirty_block_groups() and iterations of the following
3730 * loop.
3731 * Also we want to do the cache_save_setup first and then run the
3732 * delayed refs to make sure we have the best chance at doing this all
3733 * in one shot.
3734 */
3735 spin_lock(&cur_trans->dirty_bgs_lock);
3736 while (!list_empty(&cur_trans->dirty_bgs)) {
3737 cache = list_first_entry(&cur_trans->dirty_bgs,
3738 struct btrfs_block_group_cache,
3739 dirty_list);
3740
3741 /*
3742 * this can happen if cache_save_setup re-dirties a block
3743 * group that is already under IO. Just wait for it to
3744 * finish and then do it all again
3745 */
3746 if (!list_empty(&cache->io_list)) {
3747 spin_unlock(&cur_trans->dirty_bgs_lock);
3748 list_del_init(&cache->io_list);
3749 btrfs_wait_cache_io(root, trans, cache,
3750 &cache->io_ctl, path,
3751 cache->key.objectid);
3752 btrfs_put_block_group(cache);
3753 spin_lock(&cur_trans->dirty_bgs_lock);
3754 }
3755
3756 /*
3757 * don't remove from the dirty list until after we've waited
3758 * on any pending IO
3759 */
3760 list_del_init(&cache->dirty_list);
3761 spin_unlock(&cur_trans->dirty_bgs_lock);
3762 should_put = 1;
3763
3764 cache_save_setup(cache, trans, path);
3765
3766 if (!ret)
3767 ret = btrfs_run_delayed_refs(trans, root, (unsigned long) -1);
3768
3769 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
3770 cache->io_ctl.inode = NULL;
3771 ret = btrfs_write_out_cache(root, trans, cache, path);
3772 if (ret == 0 && cache->io_ctl.inode) {
3773 num_started++;
3774 should_put = 0;
3775 list_add_tail(&cache->io_list, io);
3776 } else {
3777 /*
3778 * if we failed to write the cache, the
3779 * generation will be bad and life goes on
3780 */
3781 ret = 0;
3782 }
3783 }
3784 if (!ret) {
3785 ret = write_one_cache_group(trans, root, path, cache);
3786 /*
3787 * One of the free space endio workers might have
3788 * created a new block group while updating a free space
3789 * cache's inode (at inode.c:btrfs_finish_ordered_io())
3790 * and hasn't released its transaction handle yet, in
3791 * which case the new block group is still attached to
3792 * its transaction handle and its creation has not
3793 * finished yet (no block group item in the extent tree
3794 * yet, etc). If this is the case, wait for all free
3795 * space endio workers to finish and retry. This is a
3796 * a very rare case so no need for a more efficient and
3797 * complex approach.
3798 */
3799 if (ret == -ENOENT) {
3800 wait_event(cur_trans->writer_wait,
3801 atomic_read(&cur_trans->num_writers) == 1);
3802 ret = write_one_cache_group(trans, root, path,
3803 cache);
3804 }
3805 if (ret)
3806 btrfs_abort_transaction(trans, ret);
3807 }
3808
3809 /* if its not on the io list, we need to put the block group */
3810 if (should_put)
3811 btrfs_put_block_group(cache);
3812 spin_lock(&cur_trans->dirty_bgs_lock);
3813 }
3814 spin_unlock(&cur_trans->dirty_bgs_lock);
3815
3816 while (!list_empty(io)) {
3817 cache = list_first_entry(io, struct btrfs_block_group_cache,
3818 io_list);
3819 list_del_init(&cache->io_list);
3820 btrfs_wait_cache_io(root, trans, cache,
3821 &cache->io_ctl, path, cache->key.objectid);
3822 btrfs_put_block_group(cache);
3823 }
3824
3825 btrfs_free_path(path);
3826 return ret;
3827 }
3828
3829 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3830 {
3831 struct btrfs_block_group_cache *block_group;
3832 int readonly = 0;
3833
3834 block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3835 if (!block_group || block_group->ro)
3836 readonly = 1;
3837 if (block_group)
3838 btrfs_put_block_group(block_group);
3839 return readonly;
3840 }
3841
3842 bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3843 {
3844 struct btrfs_block_group_cache *bg;
3845 bool ret = true;
3846
3847 bg = btrfs_lookup_block_group(fs_info, bytenr);
3848 if (!bg)
3849 return false;
3850
3851 spin_lock(&bg->lock);
3852 if (bg->ro)
3853 ret = false;
3854 else
3855 atomic_inc(&bg->nocow_writers);
3856 spin_unlock(&bg->lock);
3857
3858 /* no put on block group, done by btrfs_dec_nocow_writers */
3859 if (!ret)
3860 btrfs_put_block_group(bg);
3861
3862 return ret;
3863
3864 }
3865
3866 void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3867 {
3868 struct btrfs_block_group_cache *bg;
3869
3870 bg = btrfs_lookup_block_group(fs_info, bytenr);
3871 ASSERT(bg);
3872 if (atomic_dec_and_test(&bg->nocow_writers))
3873 wake_up_atomic_t(&bg->nocow_writers);
3874 /*
3875 * Once for our lookup and once for the lookup done by a previous call
3876 * to btrfs_inc_nocow_writers()
3877 */
3878 btrfs_put_block_group(bg);
3879 btrfs_put_block_group(bg);
3880 }
3881
3882 static int btrfs_wait_nocow_writers_atomic_t(atomic_t *a)
3883 {
3884 schedule();
3885 return 0;
3886 }
3887
3888 void btrfs_wait_nocow_writers(struct btrfs_block_group_cache *bg)
3889 {
3890 wait_on_atomic_t(&bg->nocow_writers,
3891 btrfs_wait_nocow_writers_atomic_t,
3892 TASK_UNINTERRUPTIBLE);
3893 }
3894
3895 static const char *alloc_name(u64 flags)
3896 {
3897 switch (flags) {
3898 case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
3899 return "mixed";
3900 case BTRFS_BLOCK_GROUP_METADATA:
3901 return "metadata";
3902 case BTRFS_BLOCK_GROUP_DATA:
3903 return "data";
3904 case BTRFS_BLOCK_GROUP_SYSTEM:
3905 return "system";
3906 default:
3907 WARN_ON(1);
3908 return "invalid-combination";
3909 };
3910 }
3911
3912 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3913 u64 total_bytes, u64 bytes_used,
3914 u64 bytes_readonly,
3915 struct btrfs_space_info **space_info)
3916 {
3917 struct btrfs_space_info *found;
3918 int i;
3919 int factor;
3920 int ret;
3921
3922 if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3923 BTRFS_BLOCK_GROUP_RAID10))
3924 factor = 2;
3925 else
3926 factor = 1;
3927
3928 found = __find_space_info(info, flags);
3929 if (found) {
3930 spin_lock(&found->lock);
3931 found->total_bytes += total_bytes;
3932 found->disk_total += total_bytes * factor;
3933 found->bytes_used += bytes_used;
3934 found->disk_used += bytes_used * factor;
3935 found->bytes_readonly += bytes_readonly;
3936 if (total_bytes > 0)
3937 found->full = 0;
3938 space_info_add_new_bytes(info, found, total_bytes -
3939 bytes_used - bytes_readonly);
3940 spin_unlock(&found->lock);
3941 *space_info = found;
3942 return 0;
3943 }
3944 found = kzalloc(sizeof(*found), GFP_NOFS);
3945 if (!found)
3946 return -ENOMEM;
3947
3948 ret = percpu_counter_init(&found->total_bytes_pinned, 0, GFP_KERNEL);
3949 if (ret) {
3950 kfree(found);
3951 return ret;
3952 }
3953
3954 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3955 INIT_LIST_HEAD(&found->block_groups[i]);
3956 init_rwsem(&found->groups_sem);
3957 spin_lock_init(&found->lock);
3958 found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3959 found->total_bytes = total_bytes;
3960 found->disk_total = total_bytes * factor;
3961 found->bytes_used = bytes_used;
3962 found->disk_used = bytes_used * factor;
3963 found->bytes_pinned = 0;
3964 found->bytes_reserved = 0;
3965 found->bytes_readonly = bytes_readonly;
3966 found->bytes_may_use = 0;
3967 found->full = 0;
3968 found->max_extent_size = 0;
3969 found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3970 found->chunk_alloc = 0;
3971 found->flush = 0;
3972 init_waitqueue_head(&found->wait);
3973 INIT_LIST_HEAD(&found->ro_bgs);
3974 INIT_LIST_HEAD(&found->tickets);
3975 INIT_LIST_HEAD(&found->priority_tickets);
3976
3977 ret = kobject_init_and_add(&found->kobj, &space_info_ktype,
3978 info->space_info_kobj, "%s",
3979 alloc_name(found->flags));
3980 if (ret) {
3981 kfree(found);
3982 return ret;
3983 }
3984
3985 *space_info = found;
3986 list_add_rcu(&found->list, &info->space_info);
3987 if (flags & BTRFS_BLOCK_GROUP_DATA)
3988 info->data_sinfo = found;
3989
3990 return ret;
3991 }
3992
3993 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3994 {
3995 u64 extra_flags = chunk_to_extended(flags) &
3996 BTRFS_EXTENDED_PROFILE_MASK;
3997
3998 write_seqlock(&fs_info->profiles_lock);
3999 if (flags & BTRFS_BLOCK_GROUP_DATA)
4000 fs_info->avail_data_alloc_bits |= extra_flags;
4001 if (flags & BTRFS_BLOCK_GROUP_METADATA)
4002 fs_info->avail_metadata_alloc_bits |= extra_flags;
4003 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4004 fs_info->avail_system_alloc_bits |= extra_flags;
4005 write_sequnlock(&fs_info->profiles_lock);
4006 }
4007
4008 /*
4009 * returns target flags in extended format or 0 if restripe for this
4010 * chunk_type is not in progress
4011 *
4012 * should be called with either volume_mutex or balance_lock held
4013 */
4014 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
4015 {
4016 struct btrfs_balance_control *bctl = fs_info->balance_ctl;
4017 u64 target = 0;
4018
4019 if (!bctl)
4020 return 0;
4021
4022 if (flags & BTRFS_BLOCK_GROUP_DATA &&
4023 bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4024 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
4025 } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
4026 bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4027 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
4028 } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
4029 bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4030 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
4031 }
4032
4033 return target;
4034 }
4035
4036 /*
4037 * @flags: available profiles in extended format (see ctree.h)
4038 *
4039 * Returns reduced profile in chunk format. If profile changing is in
4040 * progress (either running or paused) picks the target profile (if it's
4041 * already available), otherwise falls back to plain reducing.
4042 */
4043 static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
4044 {
4045 u64 num_devices = root->fs_info->fs_devices->rw_devices;
4046 u64 target;
4047 u64 raid_type;
4048 u64 allowed = 0;
4049
4050 /*
4051 * see if restripe for this chunk_type is in progress, if so
4052 * try to reduce to the target profile
4053 */
4054 spin_lock(&root->fs_info->balance_lock);
4055 target = get_restripe_target(root->fs_info, flags);
4056 if (target) {
4057 /* pick target profile only if it's already available */
4058 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
4059 spin_unlock(&root->fs_info->balance_lock);
4060 return extended_to_chunk(target);
4061 }
4062 }
4063 spin_unlock(&root->fs_info->balance_lock);
4064
4065 /* First, mask out the RAID levels which aren't possible */
4066 for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
4067 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
4068 allowed |= btrfs_raid_group[raid_type];
4069 }
4070 allowed &= flags;
4071
4072 if (allowed & BTRFS_BLOCK_GROUP_RAID6)
4073 allowed = BTRFS_BLOCK_GROUP_RAID6;
4074 else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
4075 allowed = BTRFS_BLOCK_GROUP_RAID5;
4076 else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
4077 allowed = BTRFS_BLOCK_GROUP_RAID10;
4078 else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
4079 allowed = BTRFS_BLOCK_GROUP_RAID1;
4080 else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
4081 allowed = BTRFS_BLOCK_GROUP_RAID0;
4082
4083 flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
4084
4085 return extended_to_chunk(flags | allowed);
4086 }
4087
4088 static u64 get_alloc_profile(struct btrfs_root *root, u64 orig_flags)
4089 {
4090 unsigned seq;
4091 u64 flags;
4092
4093 do {
4094 flags = orig_flags;
4095 seq = read_seqbegin(&root->fs_info->profiles_lock);
4096
4097 if (flags & BTRFS_BLOCK_GROUP_DATA)
4098 flags |= root->fs_info->avail_data_alloc_bits;
4099 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4100 flags |= root->fs_info->avail_system_alloc_bits;
4101 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
4102 flags |= root->fs_info->avail_metadata_alloc_bits;
4103 } while (read_seqretry(&root->fs_info->profiles_lock, seq));
4104
4105 return btrfs_reduce_alloc_profile(root, flags);
4106 }
4107
4108 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
4109 {
4110 u64 flags;
4111 u64 ret;
4112
4113 if (data)
4114 flags = BTRFS_BLOCK_GROUP_DATA;
4115 else if (root == root->fs_info->chunk_root)
4116 flags = BTRFS_BLOCK_GROUP_SYSTEM;
4117 else
4118 flags = BTRFS_BLOCK_GROUP_METADATA;
4119
4120 ret = get_alloc_profile(root, flags);
4121 return ret;
4122 }
4123
4124 int btrfs_alloc_data_chunk_ondemand(struct inode *inode, u64 bytes)
4125 {
4126 struct btrfs_space_info *data_sinfo;
4127 struct btrfs_root *root = BTRFS_I(inode)->root;
4128 struct btrfs_fs_info *fs_info = root->fs_info;
4129 u64 used;
4130 int ret = 0;
4131 int need_commit = 2;
4132 int have_pinned_space;
4133
4134 /* make sure bytes are sectorsize aligned */
4135 bytes = ALIGN(bytes, root->sectorsize);
4136
4137 if (btrfs_is_free_space_inode(inode)) {
4138 need_commit = 0;
4139 ASSERT(current->journal_info);
4140 }
4141
4142 data_sinfo = fs_info->data_sinfo;
4143 if (!data_sinfo)
4144 goto alloc;
4145
4146 again:
4147 /* make sure we have enough space to handle the data first */
4148 spin_lock(&data_sinfo->lock);
4149 used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
4150 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
4151 data_sinfo->bytes_may_use;
4152
4153 if (used + bytes > data_sinfo->total_bytes) {
4154 struct btrfs_trans_handle *trans;
4155
4156 /*
4157 * if we don't have enough free bytes in this space then we need
4158 * to alloc a new chunk.
4159 */
4160 if (!data_sinfo->full) {
4161 u64 alloc_target;
4162
4163 data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
4164 spin_unlock(&data_sinfo->lock);
4165 alloc:
4166 alloc_target = btrfs_get_alloc_profile(root, 1);
4167 /*
4168 * It is ugly that we don't call nolock join
4169 * transaction for the free space inode case here.
4170 * But it is safe because we only do the data space
4171 * reservation for the free space cache in the
4172 * transaction context, the common join transaction
4173 * just increase the counter of the current transaction
4174 * handler, doesn't try to acquire the trans_lock of
4175 * the fs.
4176 */
4177 trans = btrfs_join_transaction(root);
4178 if (IS_ERR(trans))
4179 return PTR_ERR(trans);
4180
4181 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4182 alloc_target,
4183 CHUNK_ALLOC_NO_FORCE);
4184 btrfs_end_transaction(trans, root);
4185 if (ret < 0) {
4186 if (ret != -ENOSPC)
4187 return ret;
4188 else {
4189 have_pinned_space = 1;
4190 goto commit_trans;
4191 }
4192 }
4193
4194 if (!data_sinfo)
4195 data_sinfo = fs_info->data_sinfo;
4196
4197 goto again;
4198 }
4199
4200 /*
4201 * If we don't have enough pinned space to deal with this
4202 * allocation, and no removed chunk in current transaction,
4203 * don't bother committing the transaction.
4204 */
4205 have_pinned_space = percpu_counter_compare(
4206 &data_sinfo->total_bytes_pinned,
4207 used + bytes - data_sinfo->total_bytes);
4208 spin_unlock(&data_sinfo->lock);
4209
4210 /* commit the current transaction and try again */
4211 commit_trans:
4212 if (need_commit &&
4213 !atomic_read(&root->fs_info->open_ioctl_trans)) {
4214 need_commit--;
4215
4216 if (need_commit > 0) {
4217 btrfs_start_delalloc_roots(fs_info, 0, -1);
4218 btrfs_wait_ordered_roots(fs_info, -1, 0, (u64)-1);
4219 }
4220
4221 trans = btrfs_join_transaction(root);
4222 if (IS_ERR(trans))
4223 return PTR_ERR(trans);
4224 if (have_pinned_space >= 0 ||
4225 test_bit(BTRFS_TRANS_HAVE_FREE_BGS,
4226 &trans->transaction->flags) ||
4227 need_commit > 0) {
4228 ret = btrfs_commit_transaction(trans, root);
4229 if (ret)
4230 return ret;
4231 /*
4232 * The cleaner kthread might still be doing iput
4233 * operations. Wait for it to finish so that
4234 * more space is released.
4235 */
4236 mutex_lock(&root->fs_info->cleaner_delayed_iput_mutex);
4237 mutex_unlock(&root->fs_info->cleaner_delayed_iput_mutex);
4238 goto again;
4239 } else {
4240 btrfs_end_transaction(trans, root);
4241 }
4242 }
4243
4244 trace_btrfs_space_reservation(root->fs_info,
4245 "space_info:enospc",
4246 data_sinfo->flags, bytes, 1);
4247 return -ENOSPC;
4248 }
4249 data_sinfo->bytes_may_use += bytes;
4250 trace_btrfs_space_reservation(root->fs_info, "space_info",
4251 data_sinfo->flags, bytes, 1);
4252 spin_unlock(&data_sinfo->lock);
4253
4254 return ret;
4255 }
4256
4257 /*
4258 * New check_data_free_space() with ability for precious data reservation
4259 * Will replace old btrfs_check_data_free_space(), but for patch split,
4260 * add a new function first and then replace it.
4261 */
4262 int btrfs_check_data_free_space(struct inode *inode, u64 start, u64 len)
4263 {
4264 struct btrfs_root *root = BTRFS_I(inode)->root;
4265 int ret;
4266
4267 /* align the range */
4268 len = round_up(start + len, root->sectorsize) -
4269 round_down(start, root->sectorsize);
4270 start = round_down(start, root->sectorsize);
4271
4272 ret = btrfs_alloc_data_chunk_ondemand(inode, len);
4273 if (ret < 0)
4274 return ret;
4275
4276 /*
4277 * Use new btrfs_qgroup_reserve_data to reserve precious data space
4278 *
4279 * TODO: Find a good method to avoid reserve data space for NOCOW
4280 * range, but don't impact performance on quota disable case.
4281 */
4282 ret = btrfs_qgroup_reserve_data(inode, start, len);
4283 return ret;
4284 }
4285
4286 /*
4287 * Called if we need to clear a data reservation for this inode
4288 * Normally in a error case.
4289 *
4290 * This one will *NOT* use accurate qgroup reserved space API, just for case
4291 * which we can't sleep and is sure it won't affect qgroup reserved space.
4292 * Like clear_bit_hook().
4293 */
4294 void btrfs_free_reserved_data_space_noquota(struct inode *inode, u64 start,
4295 u64 len)
4296 {
4297 struct btrfs_root *root = BTRFS_I(inode)->root;
4298 struct btrfs_space_info *data_sinfo;
4299
4300 /* Make sure the range is aligned to sectorsize */
4301 len = round_up(start + len, root->sectorsize) -
4302 round_down(start, root->sectorsize);
4303 start = round_down(start, root->sectorsize);
4304
4305 data_sinfo = root->fs_info->data_sinfo;
4306 spin_lock(&data_sinfo->lock);
4307 if (WARN_ON(data_sinfo->bytes_may_use < len))
4308 data_sinfo->bytes_may_use = 0;
4309 else
4310 data_sinfo->bytes_may_use -= len;
4311 trace_btrfs_space_reservation(root->fs_info, "space_info",
4312 data_sinfo->flags, len, 0);
4313 spin_unlock(&data_sinfo->lock);
4314 }
4315
4316 /*
4317 * Called if we need to clear a data reservation for this inode
4318 * Normally in a error case.
4319 *
4320 * This one will handle the per-inode data rsv map for accurate reserved
4321 * space framework.
4322 */
4323 void btrfs_free_reserved_data_space(struct inode *inode, u64 start, u64 len)
4324 {
4325 btrfs_free_reserved_data_space_noquota(inode, start, len);
4326 btrfs_qgroup_free_data(inode, start, len);
4327 }
4328
4329 static void force_metadata_allocation(struct btrfs_fs_info *info)
4330 {
4331 struct list_head *head = &info->space_info;
4332 struct btrfs_space_info *found;
4333
4334 rcu_read_lock();
4335 list_for_each_entry_rcu(found, head, list) {
4336 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
4337 found->force_alloc = CHUNK_ALLOC_FORCE;
4338 }
4339 rcu_read_unlock();
4340 }
4341
4342 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
4343 {
4344 return (global->size << 1);
4345 }
4346
4347 static int should_alloc_chunk(struct btrfs_root *root,
4348 struct btrfs_space_info *sinfo, int force)
4349 {
4350 struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4351 u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
4352 u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
4353 u64 thresh;
4354
4355 if (force == CHUNK_ALLOC_FORCE)
4356 return 1;
4357
4358 /*
4359 * We need to take into account the global rsv because for all intents
4360 * and purposes it's used space. Don't worry about locking the
4361 * global_rsv, it doesn't change except when the transaction commits.
4362 */
4363 if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
4364 num_allocated += calc_global_rsv_need_space(global_rsv);
4365
4366 /*
4367 * in limited mode, we want to have some free space up to
4368 * about 1% of the FS size.
4369 */
4370 if (force == CHUNK_ALLOC_LIMITED) {
4371 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
4372 thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
4373
4374 if (num_bytes - num_allocated < thresh)
4375 return 1;
4376 }
4377
4378 if (num_allocated + SZ_2M < div_factor(num_bytes, 8))
4379 return 0;
4380 return 1;
4381 }
4382
4383 static u64 get_profile_num_devs(struct btrfs_root *root, u64 type)
4384 {
4385 u64 num_dev;
4386
4387 if (type & (BTRFS_BLOCK_GROUP_RAID10 |
4388 BTRFS_BLOCK_GROUP_RAID0 |
4389 BTRFS_BLOCK_GROUP_RAID5 |
4390 BTRFS_BLOCK_GROUP_RAID6))
4391 num_dev = root->fs_info->fs_devices->rw_devices;
4392 else if (type & BTRFS_BLOCK_GROUP_RAID1)
4393 num_dev = 2;
4394 else
4395 num_dev = 1; /* DUP or single */
4396
4397 return num_dev;
4398 }
4399
4400 /*
4401 * If @is_allocation is true, reserve space in the system space info necessary
4402 * for allocating a chunk, otherwise if it's false, reserve space necessary for
4403 * removing a chunk.
4404 */
4405 void check_system_chunk(struct btrfs_trans_handle *trans,
4406 struct btrfs_root *root,
4407 u64 type)
4408 {
4409 struct btrfs_space_info *info;
4410 u64 left;
4411 u64 thresh;
4412 int ret = 0;
4413 u64 num_devs;
4414
4415 /*
4416 * Needed because we can end up allocating a system chunk and for an
4417 * atomic and race free space reservation in the chunk block reserve.
4418 */
4419 ASSERT(mutex_is_locked(&root->fs_info->chunk_mutex));
4420
4421 info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4422 spin_lock(&info->lock);
4423 left = info->total_bytes - info->bytes_used - info->bytes_pinned -
4424 info->bytes_reserved - info->bytes_readonly -
4425 info->bytes_may_use;
4426 spin_unlock(&info->lock);
4427
4428 num_devs = get_profile_num_devs(root, type);
4429
4430 /* num_devs device items to update and 1 chunk item to add or remove */
4431 thresh = btrfs_calc_trunc_metadata_size(root, num_devs) +
4432 btrfs_calc_trans_metadata_size(root, 1);
4433
4434 if (left < thresh && btrfs_test_opt(root->fs_info, ENOSPC_DEBUG)) {
4435 btrfs_info(root->fs_info, "left=%llu, need=%llu, flags=%llu",
4436 left, thresh, type);
4437 dump_space_info(info, 0, 0);
4438 }
4439
4440 if (left < thresh) {
4441 u64 flags;
4442
4443 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
4444 /*
4445 * Ignore failure to create system chunk. We might end up not
4446 * needing it, as we might not need to COW all nodes/leafs from
4447 * the paths we visit in the chunk tree (they were already COWed
4448 * or created in the current transaction for example).
4449 */
4450 ret = btrfs_alloc_chunk(trans, root, flags);
4451 }
4452
4453 if (!ret) {
4454 ret = btrfs_block_rsv_add(root->fs_info->chunk_root,
4455 &root->fs_info->chunk_block_rsv,
4456 thresh, BTRFS_RESERVE_NO_FLUSH);
4457 if (!ret)
4458 trans->chunk_bytes_reserved += thresh;
4459 }
4460 }
4461
4462 /*
4463 * If force is CHUNK_ALLOC_FORCE:
4464 * - return 1 if it successfully allocates a chunk,
4465 * - return errors including -ENOSPC otherwise.
4466 * If force is NOT CHUNK_ALLOC_FORCE:
4467 * - return 0 if it doesn't need to allocate a new chunk,
4468 * - return 1 if it successfully allocates a chunk,
4469 * - return errors including -ENOSPC otherwise.
4470 */
4471 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
4472 struct btrfs_root *extent_root, u64 flags, int force)
4473 {
4474 struct btrfs_space_info *space_info;
4475 struct btrfs_fs_info *fs_info = extent_root->fs_info;
4476 int wait_for_alloc = 0;
4477 int ret = 0;
4478
4479 /* Don't re-enter if we're already allocating a chunk */
4480 if (trans->allocating_chunk)
4481 return -ENOSPC;
4482
4483 space_info = __find_space_info(extent_root->fs_info, flags);
4484 if (!space_info) {
4485 ret = update_space_info(extent_root->fs_info, flags,
4486 0, 0, 0, &space_info);
4487 BUG_ON(ret); /* -ENOMEM */
4488 }
4489 BUG_ON(!space_info); /* Logic error */
4490
4491 again:
4492 spin_lock(&space_info->lock);
4493 if (force < space_info->force_alloc)
4494 force = space_info->force_alloc;
4495 if (space_info->full) {
4496 if (should_alloc_chunk(extent_root, space_info, force))
4497 ret = -ENOSPC;
4498 else
4499 ret = 0;
4500 spin_unlock(&space_info->lock);
4501 return ret;
4502 }
4503
4504 if (!should_alloc_chunk(extent_root, space_info, force)) {
4505 spin_unlock(&space_info->lock);
4506 return 0;
4507 } else if (space_info->chunk_alloc) {
4508 wait_for_alloc = 1;
4509 } else {
4510 space_info->chunk_alloc = 1;
4511 }
4512
4513 spin_unlock(&space_info->lock);
4514
4515 mutex_lock(&fs_info->chunk_mutex);
4516
4517 /*
4518 * The chunk_mutex is held throughout the entirety of a chunk
4519 * allocation, so once we've acquired the chunk_mutex we know that the
4520 * other guy is done and we need to recheck and see if we should
4521 * allocate.
4522 */
4523 if (wait_for_alloc) {
4524 mutex_unlock(&fs_info->chunk_mutex);
4525 wait_for_alloc = 0;
4526 goto again;
4527 }
4528
4529 trans->allocating_chunk = true;
4530
4531 /*
4532 * If we have mixed data/metadata chunks we want to make sure we keep
4533 * allocating mixed chunks instead of individual chunks.
4534 */
4535 if (btrfs_mixed_space_info(space_info))
4536 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
4537
4538 /*
4539 * if we're doing a data chunk, go ahead and make sure that
4540 * we keep a reasonable number of metadata chunks allocated in the
4541 * FS as well.
4542 */
4543 if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
4544 fs_info->data_chunk_allocations++;
4545 if (!(fs_info->data_chunk_allocations %
4546 fs_info->metadata_ratio))
4547 force_metadata_allocation(fs_info);
4548 }
4549
4550 /*
4551 * Check if we have enough space in SYSTEM chunk because we may need
4552 * to update devices.
4553 */
4554 check_system_chunk(trans, extent_root, flags);
4555
4556 ret = btrfs_alloc_chunk(trans, extent_root, flags);
4557 trans->allocating_chunk = false;
4558
4559 spin_lock(&space_info->lock);
4560 if (ret < 0 && ret != -ENOSPC)
4561 goto out;
4562 if (ret)
4563 space_info->full = 1;
4564 else
4565 ret = 1;
4566
4567 space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4568 out:
4569 space_info->chunk_alloc = 0;
4570 spin_unlock(&space_info->lock);
4571 mutex_unlock(&fs_info->chunk_mutex);
4572 /*
4573 * When we allocate a new chunk we reserve space in the chunk block
4574 * reserve to make sure we can COW nodes/leafs in the chunk tree or
4575 * add new nodes/leafs to it if we end up needing to do it when
4576 * inserting the chunk item and updating device items as part of the
4577 * second phase of chunk allocation, performed by
4578 * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
4579 * large number of new block groups to create in our transaction
4580 * handle's new_bgs list to avoid exhausting the chunk block reserve
4581 * in extreme cases - like having a single transaction create many new
4582 * block groups when starting to write out the free space caches of all
4583 * the block groups that were made dirty during the lifetime of the
4584 * transaction.
4585 */
4586 if (trans->can_flush_pending_bgs &&
4587 trans->chunk_bytes_reserved >= (u64)SZ_2M) {
4588 btrfs_create_pending_block_groups(trans, extent_root);
4589 btrfs_trans_release_chunk_metadata(trans);
4590 }
4591 return ret;
4592 }
4593
4594 static int can_overcommit(struct btrfs_root *root,
4595 struct btrfs_space_info *space_info, u64 bytes,
4596 enum btrfs_reserve_flush_enum flush)
4597 {
4598 struct btrfs_block_rsv *global_rsv;
4599 u64 profile;
4600 u64 space_size;
4601 u64 avail;
4602 u64 used;
4603
4604 /* Don't overcommit when in mixed mode. */
4605 if (space_info->flags & BTRFS_BLOCK_GROUP_DATA)
4606 return 0;
4607
4608 BUG_ON(root->fs_info == NULL);
4609 global_rsv = &root->fs_info->global_block_rsv;
4610 profile = btrfs_get_alloc_profile(root, 0);
4611 used = space_info->bytes_used + space_info->bytes_reserved +
4612 space_info->bytes_pinned + space_info->bytes_readonly;
4613
4614 /*
4615 * We only want to allow over committing if we have lots of actual space
4616 * free, but if we don't have enough space to handle the global reserve
4617 * space then we could end up having a real enospc problem when trying
4618 * to allocate a chunk or some other such important allocation.
4619 */
4620 spin_lock(&global_rsv->lock);
4621 space_size = calc_global_rsv_need_space(global_rsv);
4622 spin_unlock(&global_rsv->lock);
4623 if (used + space_size >= space_info->total_bytes)
4624 return 0;
4625
4626 used += space_info->bytes_may_use;
4627
4628 spin_lock(&root->fs_info->free_chunk_lock);
4629 avail = root->fs_info->free_chunk_space;
4630 spin_unlock(&root->fs_info->free_chunk_lock);
4631
4632 /*
4633 * If we have dup, raid1 or raid10 then only half of the free
4634 * space is actually useable. For raid56, the space info used
4635 * doesn't include the parity drive, so we don't have to
4636 * change the math
4637 */
4638 if (profile & (BTRFS_BLOCK_GROUP_DUP |
4639 BTRFS_BLOCK_GROUP_RAID1 |
4640 BTRFS_BLOCK_GROUP_RAID10))
4641 avail >>= 1;
4642
4643 /*
4644 * If we aren't flushing all things, let us overcommit up to
4645 * 1/2th of the space. If we can flush, don't let us overcommit
4646 * too much, let it overcommit up to 1/8 of the space.
4647 */
4648 if (flush == BTRFS_RESERVE_FLUSH_ALL)
4649 avail >>= 3;
4650 else
4651 avail >>= 1;
4652
4653 if (used + bytes < space_info->total_bytes + avail)
4654 return 1;
4655 return 0;
4656 }
4657
4658 static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
4659 unsigned long nr_pages, int nr_items)
4660 {
4661 struct super_block *sb = root->fs_info->sb;
4662
4663 if (down_read_trylock(&sb->s_umount)) {
4664 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
4665 up_read(&sb->s_umount);
4666 } else {
4667 /*
4668 * We needn't worry the filesystem going from r/w to r/o though
4669 * we don't acquire ->s_umount mutex, because the filesystem
4670 * should guarantee the delalloc inodes list be empty after
4671 * the filesystem is readonly(all dirty pages are written to
4672 * the disk).
4673 */
4674 btrfs_start_delalloc_roots(root->fs_info, 0, nr_items);
4675 if (!current->journal_info)
4676 btrfs_wait_ordered_roots(root->fs_info, nr_items,
4677 0, (u64)-1);
4678 }
4679 }
4680
4681 static inline int calc_reclaim_items_nr(struct btrfs_root *root, u64 to_reclaim)
4682 {
4683 u64 bytes;
4684 int nr;
4685
4686 bytes = btrfs_calc_trans_metadata_size(root, 1);
4687 nr = (int)div64_u64(to_reclaim, bytes);
4688 if (!nr)
4689 nr = 1;
4690 return nr;
4691 }
4692
4693 #define EXTENT_SIZE_PER_ITEM SZ_256K
4694
4695 /*
4696 * shrink metadata reservation for delalloc
4697 */
4698 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
4699 bool wait_ordered)
4700 {
4701 struct btrfs_block_rsv *block_rsv;
4702 struct btrfs_space_info *space_info;
4703 struct btrfs_trans_handle *trans;
4704 u64 delalloc_bytes;
4705 u64 max_reclaim;
4706 long time_left;
4707 unsigned long nr_pages;
4708 int loops;
4709 int items;
4710 enum btrfs_reserve_flush_enum flush;
4711
4712 /* Calc the number of the pages we need flush for space reservation */
4713 items = calc_reclaim_items_nr(root, to_reclaim);
4714 to_reclaim = (u64)items * EXTENT_SIZE_PER_ITEM;
4715
4716 trans = (struct btrfs_trans_handle *)current->journal_info;
4717 block_rsv = &root->fs_info->delalloc_block_rsv;
4718 space_info = block_rsv->space_info;
4719
4720 delalloc_bytes = percpu_counter_sum_positive(
4721 &root->fs_info->delalloc_bytes);
4722 if (delalloc_bytes == 0) {
4723 if (trans)
4724 return;
4725 if (wait_ordered)
4726 btrfs_wait_ordered_roots(root->fs_info, items,
4727 0, (u64)-1);
4728 return;
4729 }
4730
4731 loops = 0;
4732 while (delalloc_bytes && loops < 3) {
4733 max_reclaim = min(delalloc_bytes, to_reclaim);
4734 nr_pages = max_reclaim >> PAGE_SHIFT;
4735 btrfs_writeback_inodes_sb_nr(root, nr_pages, items);
4736 /*
4737 * We need to wait for the async pages to actually start before
4738 * we do anything.
4739 */
4740 max_reclaim = atomic_read(&root->fs_info->async_delalloc_pages);
4741 if (!max_reclaim)
4742 goto skip_async;
4743
4744 if (max_reclaim <= nr_pages)
4745 max_reclaim = 0;
4746 else
4747 max_reclaim -= nr_pages;
4748
4749 wait_event(root->fs_info->async_submit_wait,
4750 atomic_read(&root->fs_info->async_delalloc_pages) <=
4751 (int)max_reclaim);
4752 skip_async:
4753 if (!trans)
4754 flush = BTRFS_RESERVE_FLUSH_ALL;
4755 else
4756 flush = BTRFS_RESERVE_NO_FLUSH;
4757 spin_lock(&space_info->lock);
4758 if (can_overcommit(root, space_info, orig, flush)) {
4759 spin_unlock(&space_info->lock);
4760 break;
4761 }
4762 if (list_empty(&space_info->tickets) &&
4763 list_empty(&space_info->priority_tickets)) {
4764 spin_unlock(&space_info->lock);
4765 break;
4766 }
4767 spin_unlock(&space_info->lock);
4768
4769 loops++;
4770 if (wait_ordered && !trans) {
4771 btrfs_wait_ordered_roots(root->fs_info, items,
4772 0, (u64)-1);
4773 } else {
4774 time_left = schedule_timeout_killable(1);
4775 if (time_left)
4776 break;
4777 }
4778 delalloc_bytes = percpu_counter_sum_positive(
4779 &root->fs_info->delalloc_bytes);
4780 }
4781 }
4782
4783 /**
4784 * maybe_commit_transaction - possibly commit the transaction if its ok to
4785 * @root - the root we're allocating for
4786 * @bytes - the number of bytes we want to reserve
4787 * @force - force the commit
4788 *
4789 * This will check to make sure that committing the transaction will actually
4790 * get us somewhere and then commit the transaction if it does. Otherwise it
4791 * will return -ENOSPC.
4792 */
4793 static int may_commit_transaction(struct btrfs_root *root,
4794 struct btrfs_space_info *space_info,
4795 u64 bytes, int force)
4796 {
4797 struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
4798 struct btrfs_trans_handle *trans;
4799
4800 trans = (struct btrfs_trans_handle *)current->journal_info;
4801 if (trans)
4802 return -EAGAIN;
4803
4804 if (force)
4805 goto commit;
4806
4807 /* See if there is enough pinned space to make this reservation */
4808 if (percpu_counter_compare(&space_info->total_bytes_pinned,
4809 bytes) >= 0)
4810 goto commit;
4811
4812 /*
4813 * See if there is some space in the delayed insertion reservation for
4814 * this reservation.
4815 */
4816 if (space_info != delayed_rsv->space_info)
4817 return -ENOSPC;
4818
4819 spin_lock(&delayed_rsv->lock);
4820 if (percpu_counter_compare(&space_info->total_bytes_pinned,
4821 bytes - delayed_rsv->size) >= 0) {
4822 spin_unlock(&delayed_rsv->lock);
4823 return -ENOSPC;
4824 }
4825 spin_unlock(&delayed_rsv->lock);
4826
4827 commit:
4828 trans = btrfs_join_transaction(root);
4829 if (IS_ERR(trans))
4830 return -ENOSPC;
4831
4832 return btrfs_commit_transaction(trans, root);
4833 }
4834
4835 struct reserve_ticket {
4836 u64 bytes;
4837 int error;
4838 struct list_head list;
4839 wait_queue_head_t wait;
4840 };
4841
4842 static int flush_space(struct btrfs_root *root,
4843 struct btrfs_space_info *space_info, u64 num_bytes,
4844 u64 orig_bytes, int state)
4845 {
4846 struct btrfs_trans_handle *trans;
4847 int nr;
4848 int ret = 0;
4849
4850 switch (state) {
4851 case FLUSH_DELAYED_ITEMS_NR:
4852 case FLUSH_DELAYED_ITEMS:
4853 if (state == FLUSH_DELAYED_ITEMS_NR)
4854 nr = calc_reclaim_items_nr(root, num_bytes) * 2;
4855 else
4856 nr = -1;
4857
4858 trans = btrfs_join_transaction(root);
4859 if (IS_ERR(trans)) {
4860 ret = PTR_ERR(trans);
4861 break;
4862 }
4863 ret = btrfs_run_delayed_items_nr(trans, root, nr);
4864 btrfs_end_transaction(trans, root);
4865 break;
4866 case FLUSH_DELALLOC:
4867 case FLUSH_DELALLOC_WAIT:
4868 shrink_delalloc(root, num_bytes * 2, orig_bytes,
4869 state == FLUSH_DELALLOC_WAIT);
4870 break;
4871 case ALLOC_CHUNK:
4872 trans = btrfs_join_transaction(root);
4873 if (IS_ERR(trans)) {
4874 ret = PTR_ERR(trans);
4875 break;
4876 }
4877 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4878 btrfs_get_alloc_profile(root, 0),
4879 CHUNK_ALLOC_NO_FORCE);
4880 btrfs_end_transaction(trans, root);
4881 if (ret > 0 || ret == -ENOSPC)
4882 ret = 0;
4883 break;
4884 case COMMIT_TRANS:
4885 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
4886 break;
4887 default:
4888 ret = -ENOSPC;
4889 break;
4890 }
4891
4892 trace_btrfs_flush_space(root->fs_info, space_info->flags, num_bytes,
4893 orig_bytes, state, ret);
4894 return ret;
4895 }
4896
4897 static inline u64
4898 btrfs_calc_reclaim_metadata_size(struct btrfs_root *root,
4899 struct btrfs_space_info *space_info)
4900 {
4901 struct reserve_ticket *ticket;
4902 u64 used;
4903 u64 expected;
4904 u64 to_reclaim = 0;
4905
4906 list_for_each_entry(ticket, &space_info->tickets, list)
4907 to_reclaim += ticket->bytes;
4908 list_for_each_entry(ticket, &space_info->priority_tickets, list)
4909 to_reclaim += ticket->bytes;
4910 if (to_reclaim)
4911 return to_reclaim;
4912
4913 to_reclaim = min_t(u64, num_online_cpus() * SZ_1M, SZ_16M);
4914 if (can_overcommit(root, space_info, to_reclaim,
4915 BTRFS_RESERVE_FLUSH_ALL))
4916 return 0;
4917
4918 used = space_info->bytes_used + space_info->bytes_reserved +
4919 space_info->bytes_pinned + space_info->bytes_readonly +
4920 space_info->bytes_may_use;
4921 if (can_overcommit(root, space_info, SZ_1M, BTRFS_RESERVE_FLUSH_ALL))
4922 expected = div_factor_fine(space_info->total_bytes, 95);
4923 else
4924 expected = div_factor_fine(space_info->total_bytes, 90);
4925
4926 if (used > expected)
4927 to_reclaim = used - expected;
4928 else
4929 to_reclaim = 0;
4930 to_reclaim = min(to_reclaim, space_info->bytes_may_use +
4931 space_info->bytes_reserved);
4932 return to_reclaim;
4933 }
4934
4935 static inline int need_do_async_reclaim(struct btrfs_space_info *space_info,
4936 struct btrfs_root *root, u64 used)
4937 {
4938 u64 thresh = div_factor_fine(space_info->total_bytes, 98);
4939
4940 /* If we're just plain full then async reclaim just slows us down. */
4941 if ((space_info->bytes_used + space_info->bytes_reserved) >= thresh)
4942 return 0;
4943
4944 if (!btrfs_calc_reclaim_metadata_size(root, space_info))
4945 return 0;
4946
4947 return (used >= thresh && !btrfs_fs_closing(root->fs_info) &&
4948 !test_bit(BTRFS_FS_STATE_REMOUNTING,
4949 &root->fs_info->fs_state));
4950 }
4951
4952 static void wake_all_tickets(struct list_head *head)
4953 {
4954 struct reserve_ticket *ticket;
4955
4956 while (!list_empty(head)) {
4957 ticket = list_first_entry(head, struct reserve_ticket, list);
4958 list_del_init(&ticket->list);
4959 ticket->error = -ENOSPC;
4960 wake_up(&ticket->wait);
4961 }
4962 }
4963
4964 /*
4965 * This is for normal flushers, we can wait all goddamned day if we want to. We
4966 * will loop and continuously try to flush as long as we are making progress.
4967 * We count progress as clearing off tickets each time we have to loop.
4968 */
4969 static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
4970 {
4971 struct reserve_ticket *last_ticket = NULL;
4972 struct btrfs_fs_info *fs_info;
4973 struct btrfs_space_info *space_info;
4974 u64 to_reclaim;
4975 int flush_state;
4976 int commit_cycles = 0;
4977
4978 fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
4979 space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4980
4981 spin_lock(&space_info->lock);
4982 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
4983 space_info);
4984 if (!to_reclaim) {
4985 space_info->flush = 0;
4986 spin_unlock(&space_info->lock);
4987 return;
4988 }
4989 last_ticket = list_first_entry(&space_info->tickets,
4990 struct reserve_ticket, list);
4991 spin_unlock(&space_info->lock);
4992
4993 flush_state = FLUSH_DELAYED_ITEMS_NR;
4994 do {
4995 struct reserve_ticket *ticket;
4996 int ret;
4997
4998 ret = flush_space(fs_info->fs_root, space_info, to_reclaim,
4999 to_reclaim, flush_state);
5000 spin_lock(&space_info->lock);
5001 if (list_empty(&space_info->tickets)) {
5002 space_info->flush = 0;
5003 spin_unlock(&space_info->lock);
5004 return;
5005 }
5006 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
5007 space_info);
5008 ticket = list_first_entry(&space_info->tickets,
5009 struct reserve_ticket, list);
5010 if (last_ticket == ticket) {
5011 flush_state++;
5012 } else {
5013 last_ticket = ticket;
5014 flush_state = FLUSH_DELAYED_ITEMS_NR;
5015 if (commit_cycles)
5016 commit_cycles--;
5017 }
5018
5019 if (flush_state > COMMIT_TRANS) {
5020 commit_cycles++;
5021 if (commit_cycles > 2) {
5022 wake_all_tickets(&space_info->tickets);
5023 space_info->flush = 0;
5024 } else {
5025 flush_state = FLUSH_DELAYED_ITEMS_NR;
5026 }
5027 }
5028 spin_unlock(&space_info->lock);
5029 } while (flush_state <= COMMIT_TRANS);
5030 }
5031
5032 void btrfs_init_async_reclaim_work(struct work_struct *work)
5033 {
5034 INIT_WORK(work, btrfs_async_reclaim_metadata_space);
5035 }
5036
5037 static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
5038 struct btrfs_space_info *space_info,
5039 struct reserve_ticket *ticket)
5040 {
5041 u64 to_reclaim;
5042 int flush_state = FLUSH_DELAYED_ITEMS_NR;
5043
5044 spin_lock(&space_info->lock);
5045 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
5046 space_info);
5047 if (!to_reclaim) {
5048 spin_unlock(&space_info->lock);
5049 return;
5050 }
5051 spin_unlock(&space_info->lock);
5052
5053 do {
5054 flush_space(fs_info->fs_root, space_info, to_reclaim,
5055 to_reclaim, flush_state);
5056 flush_state++;
5057 spin_lock(&space_info->lock);
5058 if (ticket->bytes == 0) {
5059 spin_unlock(&space_info->lock);
5060 return;
5061 }
5062 spin_unlock(&space_info->lock);
5063
5064 /*
5065 * Priority flushers can't wait on delalloc without
5066 * deadlocking.
5067 */
5068 if (flush_state == FLUSH_DELALLOC ||
5069 flush_state == FLUSH_DELALLOC_WAIT)
5070 flush_state = ALLOC_CHUNK;
5071 } while (flush_state < COMMIT_TRANS);
5072 }
5073
5074 static int wait_reserve_ticket(struct btrfs_fs_info *fs_info,
5075 struct btrfs_space_info *space_info,
5076 struct reserve_ticket *ticket, u64 orig_bytes)
5077
5078 {
5079 DEFINE_WAIT(wait);
5080 int ret = 0;
5081
5082 spin_lock(&space_info->lock);
5083 while (ticket->bytes > 0 && ticket->error == 0) {
5084 ret = prepare_to_wait_event(&ticket->wait, &wait, TASK_KILLABLE);
5085 if (ret) {
5086 ret = -EINTR;
5087 break;
5088 }
5089 spin_unlock(&space_info->lock);
5090
5091 schedule();
5092
5093 finish_wait(&ticket->wait, &wait);
5094 spin_lock(&space_info->lock);
5095 }
5096 if (!ret)
5097 ret = ticket->error;
5098 if (!list_empty(&ticket->list))
5099 list_del_init(&ticket->list);
5100 if (ticket->bytes && ticket->bytes < orig_bytes) {
5101 u64 num_bytes = orig_bytes - ticket->bytes;
5102 space_info->bytes_may_use -= num_bytes;
5103 trace_btrfs_space_reservation(fs_info, "space_info",
5104 space_info->flags, num_bytes, 0);
5105 }
5106 spin_unlock(&space_info->lock);
5107
5108 return ret;
5109 }
5110
5111 /**
5112 * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5113 * @root - the root we're allocating for
5114 * @space_info - the space info we want to allocate from
5115 * @orig_bytes - the number of bytes we want
5116 * @flush - whether or not we can flush to make our reservation
5117 *
5118 * This will reserve orig_bytes number of bytes from the space info associated
5119 * with the block_rsv. If there is not enough space it will make an attempt to
5120 * flush out space to make room. It will do this by flushing delalloc if
5121 * possible or committing the transaction. If flush is 0 then no attempts to
5122 * regain reservations will be made and this will fail if there is not enough
5123 * space already.
5124 */
5125 static int __reserve_metadata_bytes(struct btrfs_root *root,
5126 struct btrfs_space_info *space_info,
5127 u64 orig_bytes,
5128 enum btrfs_reserve_flush_enum flush)
5129 {
5130 struct reserve_ticket ticket;
5131 u64 used;
5132 int ret = 0;
5133
5134 ASSERT(orig_bytes);
5135 ASSERT(!current->journal_info || flush != BTRFS_RESERVE_FLUSH_ALL);
5136
5137 spin_lock(&space_info->lock);
5138 ret = -ENOSPC;
5139 used = space_info->bytes_used + space_info->bytes_reserved +
5140 space_info->bytes_pinned + space_info->bytes_readonly +
5141 space_info->bytes_may_use;
5142
5143 /*
5144 * If we have enough space then hooray, make our reservation and carry
5145 * on. If not see if we can overcommit, and if we can, hooray carry on.
5146 * If not things get more complicated.
5147 */
5148 if (used + orig_bytes <= space_info->total_bytes) {
5149 space_info->bytes_may_use += orig_bytes;
5150 trace_btrfs_space_reservation(root->fs_info, "space_info",
5151 space_info->flags, orig_bytes,
5152 1);
5153 ret = 0;
5154 } else if (can_overcommit(root, space_info, orig_bytes, flush)) {
5155 space_info->bytes_may_use += orig_bytes;
5156 trace_btrfs_space_reservation(root->fs_info, "space_info",
5157 space_info->flags, orig_bytes,
5158 1);
5159 ret = 0;
5160 }
5161
5162 /*
5163 * If we couldn't make a reservation then setup our reservation ticket
5164 * and kick the async worker if it's not already running.
5165 *
5166 * If we are a priority flusher then we just need to add our ticket to
5167 * the list and we will do our own flushing further down.
5168 */
5169 if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
5170 ticket.bytes = orig_bytes;
5171 ticket.error = 0;
5172 init_waitqueue_head(&ticket.wait);
5173 if (flush == BTRFS_RESERVE_FLUSH_ALL) {
5174 list_add_tail(&ticket.list, &space_info->tickets);
5175 if (!space_info->flush) {
5176 space_info->flush = 1;
5177 trace_btrfs_trigger_flush(root->fs_info,
5178 space_info->flags,
5179 orig_bytes, flush,
5180 "enospc");
5181 queue_work(system_unbound_wq,
5182 &root->fs_info->async_reclaim_work);
5183 }
5184 } else {
5185 list_add_tail(&ticket.list,
5186 &space_info->priority_tickets);
5187 }
5188 } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
5189 used += orig_bytes;
5190 /*
5191 * We will do the space reservation dance during log replay,
5192 * which means we won't have fs_info->fs_root set, so don't do
5193 * the async reclaim as we will panic.
5194 */
5195 if (!root->fs_info->log_root_recovering &&
5196 need_do_async_reclaim(space_info, root, used) &&
5197 !work_busy(&root->fs_info->async_reclaim_work)) {
5198 trace_btrfs_trigger_flush(root->fs_info,
5199 space_info->flags,
5200 orig_bytes, flush,
5201 "preempt");
5202 queue_work(system_unbound_wq,
5203 &root->fs_info->async_reclaim_work);
5204 }
5205 }
5206 spin_unlock(&space_info->lock);
5207 if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
5208 return ret;
5209
5210 if (flush == BTRFS_RESERVE_FLUSH_ALL)
5211 return wait_reserve_ticket(root->fs_info, space_info, &ticket,
5212 orig_bytes);
5213
5214 ret = 0;
5215 priority_reclaim_metadata_space(root->fs_info, space_info, &ticket);
5216 spin_lock(&space_info->lock);
5217 if (ticket.bytes) {
5218 if (ticket.bytes < orig_bytes) {
5219 u64 num_bytes = orig_bytes - ticket.bytes;
5220 space_info->bytes_may_use -= num_bytes;
5221 trace_btrfs_space_reservation(root->fs_info,
5222 "space_info", space_info->flags,
5223 num_bytes, 0);
5224
5225 }
5226 list_del_init(&ticket.list);
5227 ret = -ENOSPC;
5228 }
5229 spin_unlock(&space_info->lock);
5230 ASSERT(list_empty(&ticket.list));
5231 return ret;
5232 }
5233
5234 /**
5235 * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5236 * @root - the root we're allocating for
5237 * @block_rsv - the block_rsv we're allocating for
5238 * @orig_bytes - the number of bytes we want
5239 * @flush - whether or not we can flush to make our reservation
5240 *
5241 * This will reserve orgi_bytes number of bytes from the space info associated
5242 * with the block_rsv. If there is not enough space it will make an attempt to
5243 * flush out space to make room. It will do this by flushing delalloc if
5244 * possible or committing the transaction. If flush is 0 then no attempts to
5245 * regain reservations will be made and this will fail if there is not enough
5246 * space already.
5247 */
5248 static int reserve_metadata_bytes(struct btrfs_root *root,
5249 struct btrfs_block_rsv *block_rsv,
5250 u64 orig_bytes,
5251 enum btrfs_reserve_flush_enum flush)
5252 {
5253 int ret;
5254
5255 ret = __reserve_metadata_bytes(root, block_rsv->space_info, orig_bytes,
5256 flush);
5257 if (ret == -ENOSPC &&
5258 unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
5259 struct btrfs_block_rsv *global_rsv =
5260 &root->fs_info->global_block_rsv;
5261
5262 if (block_rsv != global_rsv &&
5263 !block_rsv_use_bytes(global_rsv, orig_bytes))
5264 ret = 0;
5265 }
5266 if (ret == -ENOSPC)
5267 trace_btrfs_space_reservation(root->fs_info,
5268 "space_info:enospc",
5269 block_rsv->space_info->flags,
5270 orig_bytes, 1);
5271 return ret;
5272 }
5273
5274 static struct btrfs_block_rsv *get_block_rsv(
5275 const struct btrfs_trans_handle *trans,
5276 const struct btrfs_root *root)
5277 {
5278 struct btrfs_block_rsv *block_rsv = NULL;
5279
5280 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
5281 (root == root->fs_info->csum_root && trans->adding_csums) ||
5282 (root == root->fs_info->uuid_root))
5283 block_rsv = trans->block_rsv;
5284
5285 if (!block_rsv)
5286 block_rsv = root->block_rsv;
5287
5288 if (!block_rsv)
5289 block_rsv = &root->fs_info->empty_block_rsv;
5290
5291 return block_rsv;
5292 }
5293
5294 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
5295 u64 num_bytes)
5296 {
5297 int ret = -ENOSPC;
5298 spin_lock(&block_rsv->lock);
5299 if (block_rsv->reserved >= num_bytes) {
5300 block_rsv->reserved -= num_bytes;
5301 if (block_rsv->reserved < block_rsv->size)
5302 block_rsv->full = 0;
5303 ret = 0;
5304 }
5305 spin_unlock(&block_rsv->lock);
5306 return ret;
5307 }
5308
5309 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
5310 u64 num_bytes, int update_size)
5311 {
5312 spin_lock(&block_rsv->lock);
5313 block_rsv->reserved += num_bytes;
5314 if (update_size)
5315 block_rsv->size += num_bytes;
5316 else if (block_rsv->reserved >= block_rsv->size)
5317 block_rsv->full = 1;
5318 spin_unlock(&block_rsv->lock);
5319 }
5320
5321 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
5322 struct btrfs_block_rsv *dest, u64 num_bytes,
5323 int min_factor)
5324 {
5325 struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5326 u64 min_bytes;
5327
5328 if (global_rsv->space_info != dest->space_info)
5329 return -ENOSPC;
5330
5331 spin_lock(&global_rsv->lock);
5332 min_bytes = div_factor(global_rsv->size, min_factor);
5333 if (global_rsv->reserved < min_bytes + num_bytes) {
5334 spin_unlock(&global_rsv->lock);
5335 return -ENOSPC;
5336 }
5337 global_rsv->reserved -= num_bytes;
5338 if (global_rsv->reserved < global_rsv->size)
5339 global_rsv->full = 0;
5340 spin_unlock(&global_rsv->lock);
5341
5342 block_rsv_add_bytes(dest, num_bytes, 1);
5343 return 0;
5344 }
5345
5346 /*
5347 * This is for space we already have accounted in space_info->bytes_may_use, so
5348 * basically when we're returning space from block_rsv's.
5349 */
5350 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
5351 struct btrfs_space_info *space_info,
5352 u64 num_bytes)
5353 {
5354 struct reserve_ticket *ticket;
5355 struct list_head *head;
5356 u64 used;
5357 enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_NO_FLUSH;
5358 bool check_overcommit = false;
5359
5360 spin_lock(&space_info->lock);
5361 head = &space_info->priority_tickets;
5362
5363 /*
5364 * If we are over our limit then we need to check and see if we can
5365 * overcommit, and if we can't then we just need to free up our space
5366 * and not satisfy any requests.
5367 */
5368 used = space_info->bytes_used + space_info->bytes_reserved +
5369 space_info->bytes_pinned + space_info->bytes_readonly +
5370 space_info->bytes_may_use;
5371 if (used - num_bytes >= space_info->total_bytes)
5372 check_overcommit = true;
5373 again:
5374 while (!list_empty(head) && num_bytes) {
5375 ticket = list_first_entry(head, struct reserve_ticket,
5376 list);
5377 /*
5378 * We use 0 bytes because this space is already reserved, so
5379 * adding the ticket space would be a double count.
5380 */
5381 if (check_overcommit &&
5382 !can_overcommit(fs_info->extent_root, space_info, 0,
5383 flush))
5384 break;
5385 if (num_bytes >= ticket->bytes) {
5386 list_del_init(&ticket->list);
5387 num_bytes -= ticket->bytes;
5388 ticket->bytes = 0;
5389 wake_up(&ticket->wait);
5390 } else {
5391 ticket->bytes -= num_bytes;
5392 num_bytes = 0;
5393 }
5394 }
5395
5396 if (num_bytes && head == &space_info->priority_tickets) {
5397 head = &space_info->tickets;
5398 flush = BTRFS_RESERVE_FLUSH_ALL;
5399 goto again;
5400 }
5401 space_info->bytes_may_use -= num_bytes;
5402 trace_btrfs_space_reservation(fs_info, "space_info",
5403 space_info->flags, num_bytes, 0);
5404 spin_unlock(&space_info->lock);
5405 }
5406
5407 /*
5408 * This is for newly allocated space that isn't accounted in
5409 * space_info->bytes_may_use yet. So if we allocate a chunk or unpin an extent
5410 * we use this helper.
5411 */
5412 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
5413 struct btrfs_space_info *space_info,
5414 u64 num_bytes)
5415 {
5416 struct reserve_ticket *ticket;
5417 struct list_head *head = &space_info->priority_tickets;
5418
5419 again:
5420 while (!list_empty(head) && num_bytes) {
5421 ticket = list_first_entry(head, struct reserve_ticket,
5422 list);
5423 if (num_bytes >= ticket->bytes) {
5424 trace_btrfs_space_reservation(fs_info, "space_info",
5425 space_info->flags,
5426 ticket->bytes, 1);
5427 list_del_init(&ticket->list);
5428 num_bytes -= ticket->bytes;
5429 space_info->bytes_may_use += ticket->bytes;
5430 ticket->bytes = 0;
5431 wake_up(&ticket->wait);
5432 } else {
5433 trace_btrfs_space_reservation(fs_info, "space_info",
5434 space_info->flags,
5435 num_bytes, 1);
5436 space_info->bytes_may_use += num_bytes;
5437 ticket->bytes -= num_bytes;
5438 num_bytes = 0;
5439 }
5440 }
5441
5442 if (num_bytes && head == &space_info->priority_tickets) {
5443 head = &space_info->tickets;
5444 goto again;
5445 }
5446 }
5447
5448 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
5449 struct btrfs_block_rsv *block_rsv,
5450 struct btrfs_block_rsv *dest, u64 num_bytes)
5451 {
5452 struct btrfs_space_info *space_info = block_rsv->space_info;
5453
5454 spin_lock(&block_rsv->lock);
5455 if (num_bytes == (u64)-1)
5456 num_bytes = block_rsv->size;
5457 block_rsv->size -= num_bytes;
5458 if (block_rsv->reserved >= block_rsv->size) {
5459 num_bytes = block_rsv->reserved - block_rsv->size;
5460 block_rsv->reserved = block_rsv->size;
5461 block_rsv->full = 1;
5462 } else {
5463 num_bytes = 0;
5464 }
5465 spin_unlock(&block_rsv->lock);
5466
5467 if (num_bytes > 0) {
5468 if (dest) {
5469 spin_lock(&dest->lock);
5470 if (!dest->full) {
5471 u64 bytes_to_add;
5472
5473 bytes_to_add = dest->size - dest->reserved;
5474 bytes_to_add = min(num_bytes, bytes_to_add);
5475 dest->reserved += bytes_to_add;
5476 if (dest->reserved >= dest->size)
5477 dest->full = 1;
5478 num_bytes -= bytes_to_add;
5479 }
5480 spin_unlock(&dest->lock);
5481 }
5482 if (num_bytes)
5483 space_info_add_old_bytes(fs_info, space_info,
5484 num_bytes);
5485 }
5486 }
5487
5488 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src,
5489 struct btrfs_block_rsv *dst, u64 num_bytes,
5490 int update_size)
5491 {
5492 int ret;
5493
5494 ret = block_rsv_use_bytes(src, num_bytes);
5495 if (ret)
5496 return ret;
5497
5498 block_rsv_add_bytes(dst, num_bytes, update_size);
5499 return 0;
5500 }
5501
5502 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
5503 {
5504 memset(rsv, 0, sizeof(*rsv));
5505 spin_lock_init(&rsv->lock);
5506 rsv->type = type;
5507 }
5508
5509 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
5510 unsigned short type)
5511 {
5512 struct btrfs_block_rsv *block_rsv;
5513 struct btrfs_fs_info *fs_info = root->fs_info;
5514
5515 block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
5516 if (!block_rsv)
5517 return NULL;
5518
5519 btrfs_init_block_rsv(block_rsv, type);
5520 block_rsv->space_info = __find_space_info(fs_info,
5521 BTRFS_BLOCK_GROUP_METADATA);
5522 return block_rsv;
5523 }
5524
5525 void btrfs_free_block_rsv(struct btrfs_root *root,
5526 struct btrfs_block_rsv *rsv)
5527 {
5528 if (!rsv)
5529 return;
5530 btrfs_block_rsv_release(root, rsv, (u64)-1);
5531 kfree(rsv);
5532 }
5533
5534 void __btrfs_free_block_rsv(struct btrfs_block_rsv *rsv)
5535 {
5536 kfree(rsv);
5537 }
5538
5539 int btrfs_block_rsv_add(struct btrfs_root *root,
5540 struct btrfs_block_rsv *block_rsv, u64 num_bytes,
5541 enum btrfs_reserve_flush_enum flush)
5542 {
5543 int ret;
5544
5545 if (num_bytes == 0)
5546 return 0;
5547
5548 ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5549 if (!ret) {
5550 block_rsv_add_bytes(block_rsv, num_bytes, 1);
5551 return 0;
5552 }
5553
5554 return ret;
5555 }
5556
5557 int btrfs_block_rsv_check(struct btrfs_root *root,
5558 struct btrfs_block_rsv *block_rsv, int min_factor)
5559 {
5560 u64 num_bytes = 0;
5561 int ret = -ENOSPC;
5562
5563 if (!block_rsv)
5564 return 0;
5565
5566 spin_lock(&block_rsv->lock);
5567 num_bytes = div_factor(block_rsv->size, min_factor);
5568 if (block_rsv->reserved >= num_bytes)
5569 ret = 0;
5570 spin_unlock(&block_rsv->lock);
5571
5572 return ret;
5573 }
5574
5575 int btrfs_block_rsv_refill(struct btrfs_root *root,
5576 struct btrfs_block_rsv *block_rsv, u64 min_reserved,
5577 enum btrfs_reserve_flush_enum flush)
5578 {
5579 u64 num_bytes = 0;
5580 int ret = -ENOSPC;
5581
5582 if (!block_rsv)
5583 return 0;
5584
5585 spin_lock(&block_rsv->lock);
5586 num_bytes = min_reserved;
5587 if (block_rsv->reserved >= num_bytes)
5588 ret = 0;
5589 else
5590 num_bytes -= block_rsv->reserved;
5591 spin_unlock(&block_rsv->lock);
5592
5593 if (!ret)
5594 return 0;
5595
5596 ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5597 if (!ret) {
5598 block_rsv_add_bytes(block_rsv, num_bytes, 0);
5599 return 0;
5600 }
5601
5602 return ret;
5603 }
5604
5605 void btrfs_block_rsv_release(struct btrfs_root *root,
5606 struct btrfs_block_rsv *block_rsv,
5607 u64 num_bytes)
5608 {
5609 struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5610 if (global_rsv == block_rsv ||
5611 block_rsv->space_info != global_rsv->space_info)
5612 global_rsv = NULL;
5613 block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
5614 num_bytes);
5615 }
5616
5617 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
5618 {
5619 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
5620 struct btrfs_space_info *sinfo = block_rsv->space_info;
5621 u64 num_bytes;
5622
5623 /*
5624 * The global block rsv is based on the size of the extent tree, the
5625 * checksum tree and the root tree. If the fs is empty we want to set
5626 * it to a minimal amount for safety.
5627 */
5628 num_bytes = btrfs_root_used(&fs_info->extent_root->root_item) +
5629 btrfs_root_used(&fs_info->csum_root->root_item) +
5630 btrfs_root_used(&fs_info->tree_root->root_item);
5631 num_bytes = max_t(u64, num_bytes, SZ_16M);
5632
5633 spin_lock(&sinfo->lock);
5634 spin_lock(&block_rsv->lock);
5635
5636 block_rsv->size = min_t(u64, num_bytes, SZ_512M);
5637
5638 if (block_rsv->reserved < block_rsv->size) {
5639 num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
5640 sinfo->bytes_reserved + sinfo->bytes_readonly +
5641 sinfo->bytes_may_use;
5642 if (sinfo->total_bytes > num_bytes) {
5643 num_bytes = sinfo->total_bytes - num_bytes;
5644 num_bytes = min(num_bytes,
5645 block_rsv->size - block_rsv->reserved);
5646 block_rsv->reserved += num_bytes;
5647 sinfo->bytes_may_use += num_bytes;
5648 trace_btrfs_space_reservation(fs_info, "space_info",
5649 sinfo->flags, num_bytes,
5650 1);
5651 }
5652 } else if (block_rsv->reserved > block_rsv->size) {
5653 num_bytes = block_rsv->reserved - block_rsv->size;
5654 sinfo->bytes_may_use -= num_bytes;
5655 trace_btrfs_space_reservation(fs_info, "space_info",
5656 sinfo->flags, num_bytes, 0);
5657 block_rsv->reserved = block_rsv->size;
5658 }
5659
5660 if (block_rsv->reserved == block_rsv->size)
5661 block_rsv->full = 1;
5662 else
5663 block_rsv->full = 0;
5664
5665 spin_unlock(&block_rsv->lock);
5666 spin_unlock(&sinfo->lock);
5667 }
5668
5669 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
5670 {
5671 struct btrfs_space_info *space_info;
5672
5673 space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
5674 fs_info->chunk_block_rsv.space_info = space_info;
5675
5676 space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5677 fs_info->global_block_rsv.space_info = space_info;
5678 fs_info->delalloc_block_rsv.space_info = space_info;
5679 fs_info->trans_block_rsv.space_info = space_info;
5680 fs_info->empty_block_rsv.space_info = space_info;
5681 fs_info->delayed_block_rsv.space_info = space_info;
5682
5683 fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
5684 fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
5685 fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
5686 fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
5687 if (fs_info->quota_root)
5688 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
5689 fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
5690
5691 update_global_block_rsv(fs_info);
5692 }
5693
5694 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
5695 {
5696 block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
5697 (u64)-1);
5698 WARN_ON(fs_info->delalloc_block_rsv.size > 0);
5699 WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
5700 WARN_ON(fs_info->trans_block_rsv.size > 0);
5701 WARN_ON(fs_info->trans_block_rsv.reserved > 0);
5702 WARN_ON(fs_info->chunk_block_rsv.size > 0);
5703 WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
5704 WARN_ON(fs_info->delayed_block_rsv.size > 0);
5705 WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
5706 }
5707
5708 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
5709 struct btrfs_root *root)
5710 {
5711 if (!trans->block_rsv)
5712 return;
5713
5714 if (!trans->bytes_reserved)
5715 return;
5716
5717 trace_btrfs_space_reservation(root->fs_info, "transaction",
5718 trans->transid, trans->bytes_reserved, 0);
5719 btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
5720 trans->bytes_reserved = 0;
5721 }
5722
5723 /*
5724 * To be called after all the new block groups attached to the transaction
5725 * handle have been created (btrfs_create_pending_block_groups()).
5726 */
5727 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
5728 {
5729 struct btrfs_fs_info *fs_info = trans->fs_info;
5730
5731 if (!trans->chunk_bytes_reserved)
5732 return;
5733
5734 WARN_ON_ONCE(!list_empty(&trans->new_bgs));
5735
5736 block_rsv_release_bytes(fs_info, &fs_info->chunk_block_rsv, NULL,
5737 trans->chunk_bytes_reserved);
5738 trans->chunk_bytes_reserved = 0;
5739 }
5740
5741 /* Can only return 0 or -ENOSPC */
5742 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
5743 struct inode *inode)
5744 {
5745 struct btrfs_root *root = BTRFS_I(inode)->root;
5746 /*
5747 * We always use trans->block_rsv here as we will have reserved space
5748 * for our orphan when starting the transaction, using get_block_rsv()
5749 * here will sometimes make us choose the wrong block rsv as we could be
5750 * doing a reloc inode for a non refcounted root.
5751 */
5752 struct btrfs_block_rsv *src_rsv = trans->block_rsv;
5753 struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
5754
5755 /*
5756 * We need to hold space in order to delete our orphan item once we've
5757 * added it, so this takes the reservation so we can release it later
5758 * when we are truly done with the orphan item.
5759 */
5760 u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5761 trace_btrfs_space_reservation(root->fs_info, "orphan",
5762 btrfs_ino(inode), num_bytes, 1);
5763 return btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes, 1);
5764 }
5765
5766 void btrfs_orphan_release_metadata(struct inode *inode)
5767 {
5768 struct btrfs_root *root = BTRFS_I(inode)->root;
5769 u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5770 trace_btrfs_space_reservation(root->fs_info, "orphan",
5771 btrfs_ino(inode), num_bytes, 0);
5772 btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
5773 }
5774
5775 /*
5776 * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
5777 * root: the root of the parent directory
5778 * rsv: block reservation
5779 * items: the number of items that we need do reservation
5780 * qgroup_reserved: used to return the reserved size in qgroup
5781 *
5782 * This function is used to reserve the space for snapshot/subvolume
5783 * creation and deletion. Those operations are different with the
5784 * common file/directory operations, they change two fs/file trees
5785 * and root tree, the number of items that the qgroup reserves is
5786 * different with the free space reservation. So we can not use
5787 * the space reservation mechanism in start_transaction().
5788 */
5789 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
5790 struct btrfs_block_rsv *rsv,
5791 int items,
5792 u64 *qgroup_reserved,
5793 bool use_global_rsv)
5794 {
5795 u64 num_bytes;
5796 int ret;
5797 struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5798
5799 if (root->fs_info->quota_enabled) {
5800 /* One for parent inode, two for dir entries */
5801 num_bytes = 3 * root->nodesize;
5802 ret = btrfs_qgroup_reserve_meta(root, num_bytes);
5803 if (ret)
5804 return ret;
5805 } else {
5806 num_bytes = 0;
5807 }
5808
5809 *qgroup_reserved = num_bytes;
5810
5811 num_bytes = btrfs_calc_trans_metadata_size(root, items);
5812 rsv->space_info = __find_space_info(root->fs_info,
5813 BTRFS_BLOCK_GROUP_METADATA);
5814 ret = btrfs_block_rsv_add(root, rsv, num_bytes,
5815 BTRFS_RESERVE_FLUSH_ALL);
5816
5817 if (ret == -ENOSPC && use_global_rsv)
5818 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes, 1);
5819
5820 if (ret && *qgroup_reserved)
5821 btrfs_qgroup_free_meta(root, *qgroup_reserved);
5822
5823 return ret;
5824 }
5825
5826 void btrfs_subvolume_release_metadata(struct btrfs_root *root,
5827 struct btrfs_block_rsv *rsv,
5828 u64 qgroup_reserved)
5829 {
5830 btrfs_block_rsv_release(root, rsv, (u64)-1);
5831 }
5832
5833 /**
5834 * drop_outstanding_extent - drop an outstanding extent
5835 * @inode: the inode we're dropping the extent for
5836 * @num_bytes: the number of bytes we're releasing.
5837 *
5838 * This is called when we are freeing up an outstanding extent, either called
5839 * after an error or after an extent is written. This will return the number of
5840 * reserved extents that need to be freed. This must be called with
5841 * BTRFS_I(inode)->lock held.
5842 */
5843 static unsigned drop_outstanding_extent(struct inode *inode, u64 num_bytes)
5844 {
5845 unsigned drop_inode_space = 0;
5846 unsigned dropped_extents = 0;
5847 unsigned num_extents = 0;
5848
5849 num_extents = (unsigned)div64_u64(num_bytes +
5850 BTRFS_MAX_EXTENT_SIZE - 1,
5851 BTRFS_MAX_EXTENT_SIZE);
5852 ASSERT(num_extents);
5853 ASSERT(BTRFS_I(inode)->outstanding_extents >= num_extents);
5854 BTRFS_I(inode)->outstanding_extents -= num_extents;
5855
5856 if (BTRFS_I(inode)->outstanding_extents == 0 &&
5857 test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5858 &BTRFS_I(inode)->runtime_flags))
5859 drop_inode_space = 1;
5860
5861 /*
5862 * If we have more or the same amount of outstanding extents than we have
5863 * reserved then we need to leave the reserved extents count alone.
5864 */
5865 if (BTRFS_I(inode)->outstanding_extents >=
5866 BTRFS_I(inode)->reserved_extents)
5867 return drop_inode_space;
5868
5869 dropped_extents = BTRFS_I(inode)->reserved_extents -
5870 BTRFS_I(inode)->outstanding_extents;
5871 BTRFS_I(inode)->reserved_extents -= dropped_extents;
5872 return dropped_extents + drop_inode_space;
5873 }
5874
5875 /**
5876 * calc_csum_metadata_size - return the amount of metadata space that must be
5877 * reserved/freed for the given bytes.
5878 * @inode: the inode we're manipulating
5879 * @num_bytes: the number of bytes in question
5880 * @reserve: 1 if we are reserving space, 0 if we are freeing space
5881 *
5882 * This adjusts the number of csum_bytes in the inode and then returns the
5883 * correct amount of metadata that must either be reserved or freed. We
5884 * calculate how many checksums we can fit into one leaf and then divide the
5885 * number of bytes that will need to be checksumed by this value to figure out
5886 * how many checksums will be required. If we are adding bytes then the number
5887 * may go up and we will return the number of additional bytes that must be
5888 * reserved. If it is going down we will return the number of bytes that must
5889 * be freed.
5890 *
5891 * This must be called with BTRFS_I(inode)->lock held.
5892 */
5893 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
5894 int reserve)
5895 {
5896 struct btrfs_root *root = BTRFS_I(inode)->root;
5897 u64 old_csums, num_csums;
5898
5899 if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
5900 BTRFS_I(inode)->csum_bytes == 0)
5901 return 0;
5902
5903 old_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5904 if (reserve)
5905 BTRFS_I(inode)->csum_bytes += num_bytes;
5906 else
5907 BTRFS_I(inode)->csum_bytes -= num_bytes;
5908 num_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5909
5910 /* No change, no need to reserve more */
5911 if (old_csums == num_csums)
5912 return 0;
5913
5914 if (reserve)
5915 return btrfs_calc_trans_metadata_size(root,
5916 num_csums - old_csums);
5917
5918 return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
5919 }
5920
5921 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
5922 {
5923 struct btrfs_root *root = BTRFS_I(inode)->root;
5924 struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
5925 u64 to_reserve = 0;
5926 u64 csum_bytes;
5927 unsigned nr_extents = 0;
5928 enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
5929 int ret = 0;
5930 bool delalloc_lock = true;
5931 u64 to_free = 0;
5932 unsigned dropped;
5933 bool release_extra = false;
5934
5935 /* If we are a free space inode we need to not flush since we will be in
5936 * the middle of a transaction commit. We also don't need the delalloc
5937 * mutex since we won't race with anybody. We need this mostly to make
5938 * lockdep shut its filthy mouth.
5939 *
5940 * If we have a transaction open (can happen if we call truncate_block
5941 * from truncate), then we need FLUSH_LIMIT so we don't deadlock.
5942 */
5943 if (btrfs_is_free_space_inode(inode)) {
5944 flush = BTRFS_RESERVE_NO_FLUSH;
5945 delalloc_lock = false;
5946 } else if (current->journal_info) {
5947 flush = BTRFS_RESERVE_FLUSH_LIMIT;
5948 }
5949
5950 if (flush != BTRFS_RESERVE_NO_FLUSH &&
5951 btrfs_transaction_in_commit(root->fs_info))
5952 schedule_timeout(1);
5953
5954 if (delalloc_lock)
5955 mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
5956
5957 num_bytes = ALIGN(num_bytes, root->sectorsize);
5958
5959 spin_lock(&BTRFS_I(inode)->lock);
5960 nr_extents = (unsigned)div64_u64(num_bytes +
5961 BTRFS_MAX_EXTENT_SIZE - 1,
5962 BTRFS_MAX_EXTENT_SIZE);
5963 BTRFS_I(inode)->outstanding_extents += nr_extents;
5964
5965 nr_extents = 0;
5966 if (BTRFS_I(inode)->outstanding_extents >
5967 BTRFS_I(inode)->reserved_extents)
5968 nr_extents += BTRFS_I(inode)->outstanding_extents -
5969 BTRFS_I(inode)->reserved_extents;
5970
5971 /* We always want to reserve a slot for updating the inode. */
5972 to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents + 1);
5973 to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
5974 csum_bytes = BTRFS_I(inode)->csum_bytes;
5975 spin_unlock(&BTRFS_I(inode)->lock);
5976
5977 if (root->fs_info->quota_enabled) {
5978 ret = btrfs_qgroup_reserve_meta(root,
5979 nr_extents * root->nodesize);
5980 if (ret)
5981 goto out_fail;
5982 }
5983
5984 ret = btrfs_block_rsv_add(root, block_rsv, to_reserve, flush);
5985 if (unlikely(ret)) {
5986 btrfs_qgroup_free_meta(root, nr_extents * root->nodesize);
5987 goto out_fail;
5988 }
5989
5990 spin_lock(&BTRFS_I(inode)->lock);
5991 if (test_and_set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5992 &BTRFS_I(inode)->runtime_flags)) {
5993 to_reserve -= btrfs_calc_trans_metadata_size(root, 1);
5994 release_extra = true;
5995 }
5996 BTRFS_I(inode)->reserved_extents += nr_extents;
5997 spin_unlock(&BTRFS_I(inode)->lock);
5998
5999 if (delalloc_lock)
6000 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
6001
6002 if (to_reserve)
6003 trace_btrfs_space_reservation(root->fs_info, "delalloc",
6004 btrfs_ino(inode), to_reserve, 1);
6005 if (release_extra)
6006 btrfs_block_rsv_release(root, block_rsv,
6007 btrfs_calc_trans_metadata_size(root,
6008 1));
6009 return 0;
6010
6011 out_fail:
6012 spin_lock(&BTRFS_I(inode)->lock);
6013 dropped = drop_outstanding_extent(inode, num_bytes);
6014 /*
6015 * If the inodes csum_bytes is the same as the original
6016 * csum_bytes then we know we haven't raced with any free()ers
6017 * so we can just reduce our inodes csum bytes and carry on.
6018 */
6019 if (BTRFS_I(inode)->csum_bytes == csum_bytes) {
6020 calc_csum_metadata_size(inode, num_bytes, 0);
6021 } else {
6022 u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes;
6023 u64 bytes;
6024
6025 /*
6026 * This is tricky, but first we need to figure out how much we
6027 * freed from any free-ers that occurred during this
6028 * reservation, so we reset ->csum_bytes to the csum_bytes
6029 * before we dropped our lock, and then call the free for the
6030 * number of bytes that were freed while we were trying our
6031 * reservation.
6032 */
6033 bytes = csum_bytes - BTRFS_I(inode)->csum_bytes;
6034 BTRFS_I(inode)->csum_bytes = csum_bytes;
6035 to_free = calc_csum_metadata_size(inode, bytes, 0);
6036
6037
6038 /*
6039 * Now we need to see how much we would have freed had we not
6040 * been making this reservation and our ->csum_bytes were not
6041 * artificially inflated.
6042 */
6043 BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes;
6044 bytes = csum_bytes - orig_csum_bytes;
6045 bytes = calc_csum_metadata_size(inode, bytes, 0);
6046
6047 /*
6048 * Now reset ->csum_bytes to what it should be. If bytes is
6049 * more than to_free then we would have freed more space had we
6050 * not had an artificially high ->csum_bytes, so we need to free
6051 * the remainder. If bytes is the same or less then we don't
6052 * need to do anything, the other free-ers did the correct
6053 * thing.
6054 */
6055 BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes;
6056 if (bytes > to_free)
6057 to_free = bytes - to_free;
6058 else
6059 to_free = 0;
6060 }
6061 spin_unlock(&BTRFS_I(inode)->lock);
6062 if (dropped)
6063 to_free += btrfs_calc_trans_metadata_size(root, dropped);
6064
6065 if (to_free) {
6066 btrfs_block_rsv_release(root, block_rsv, to_free);
6067 trace_btrfs_space_reservation(root->fs_info, "delalloc",
6068 btrfs_ino(inode), to_free, 0);
6069 }
6070 if (delalloc_lock)
6071 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
6072 return ret;
6073 }
6074
6075 /**
6076 * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
6077 * @inode: the inode to release the reservation for
6078 * @num_bytes: the number of bytes we're releasing
6079 *
6080 * This will release the metadata reservation for an inode. This can be called
6081 * once we complete IO for a given set of bytes to release their metadata
6082 * reservations.
6083 */
6084 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
6085 {
6086 struct btrfs_root *root = BTRFS_I(inode)->root;
6087 u64 to_free = 0;
6088 unsigned dropped;
6089
6090 num_bytes = ALIGN(num_bytes, root->sectorsize);
6091 spin_lock(&BTRFS_I(inode)->lock);
6092 dropped = drop_outstanding_extent(inode, num_bytes);
6093
6094 if (num_bytes)
6095 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
6096 spin_unlock(&BTRFS_I(inode)->lock);
6097 if (dropped > 0)
6098 to_free += btrfs_calc_trans_metadata_size(root, dropped);
6099
6100 if (btrfs_is_testing(root->fs_info))
6101 return;
6102
6103 trace_btrfs_space_reservation(root->fs_info, "delalloc",
6104 btrfs_ino(inode), to_free, 0);
6105
6106 btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
6107 to_free);
6108 }
6109
6110 /**
6111 * btrfs_delalloc_reserve_space - reserve data and metadata space for
6112 * delalloc
6113 * @inode: inode we're writing to
6114 * @start: start range we are writing to
6115 * @len: how long the range we are writing to
6116 *
6117 * TODO: This function will finally replace old btrfs_delalloc_reserve_space()
6118 *
6119 * This will do the following things
6120 *
6121 * o reserve space in data space info for num bytes
6122 * and reserve precious corresponding qgroup space
6123 * (Done in check_data_free_space)
6124 *
6125 * o reserve space for metadata space, based on the number of outstanding
6126 * extents and how much csums will be needed
6127 * also reserve metadata space in a per root over-reserve method.
6128 * o add to the inodes->delalloc_bytes
6129 * o add it to the fs_info's delalloc inodes list.
6130 * (Above 3 all done in delalloc_reserve_metadata)
6131 *
6132 * Return 0 for success
6133 * Return <0 for error(-ENOSPC or -EQUOT)
6134 */
6135 int btrfs_delalloc_reserve_space(struct inode *inode, u64 start, u64 len)
6136 {
6137 int ret;
6138
6139 ret = btrfs_check_data_free_space(inode, start, len);
6140 if (ret < 0)
6141 return ret;
6142 ret = btrfs_delalloc_reserve_metadata(inode, len);
6143 if (ret < 0)
6144 btrfs_free_reserved_data_space(inode, start, len);
6145 return ret;
6146 }
6147
6148 /**
6149 * btrfs_delalloc_release_space - release data and metadata space for delalloc
6150 * @inode: inode we're releasing space for
6151 * @start: start position of the space already reserved
6152 * @len: the len of the space already reserved
6153 *
6154 * This must be matched with a call to btrfs_delalloc_reserve_space. This is
6155 * called in the case that we don't need the metadata AND data reservations
6156 * anymore. So if there is an error or we insert an inline extent.
6157 *
6158 * This function will release the metadata space that was not used and will
6159 * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
6160 * list if there are no delalloc bytes left.
6161 * Also it will handle the qgroup reserved space.
6162 */
6163 void btrfs_delalloc_release_space(struct inode *inode, u64 start, u64 len)
6164 {
6165 btrfs_delalloc_release_metadata(inode, len);
6166 btrfs_free_reserved_data_space(inode, start, len);
6167 }
6168
6169 static int update_block_group(struct btrfs_trans_handle *trans,
6170 struct btrfs_root *root, u64 bytenr,
6171 u64 num_bytes, int alloc)
6172 {
6173 struct btrfs_block_group_cache *cache = NULL;
6174 struct btrfs_fs_info *info = root->fs_info;
6175 u64 total = num_bytes;
6176 u64 old_val;
6177 u64 byte_in_group;
6178 int factor;
6179
6180 /* block accounting for super block */
6181 spin_lock(&info->delalloc_root_lock);
6182 old_val = btrfs_super_bytes_used(info->super_copy);
6183 if (alloc)
6184 old_val += num_bytes;
6185 else
6186 old_val -= num_bytes;
6187 btrfs_set_super_bytes_used(info->super_copy, old_val);
6188 spin_unlock(&info->delalloc_root_lock);
6189
6190 while (total) {
6191 cache = btrfs_lookup_block_group(info, bytenr);
6192 if (!cache)
6193 return -ENOENT;
6194 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
6195 BTRFS_BLOCK_GROUP_RAID1 |
6196 BTRFS_BLOCK_GROUP_RAID10))
6197 factor = 2;
6198 else
6199 factor = 1;
6200 /*
6201 * If this block group has free space cache written out, we
6202 * need to make sure to load it if we are removing space. This
6203 * is because we need the unpinning stage to actually add the
6204 * space back to the block group, otherwise we will leak space.
6205 */
6206 if (!alloc && cache->cached == BTRFS_CACHE_NO)
6207 cache_block_group(cache, 1);
6208
6209 byte_in_group = bytenr - cache->key.objectid;
6210 WARN_ON(byte_in_group > cache->key.offset);
6211
6212 spin_lock(&cache->space_info->lock);
6213 spin_lock(&cache->lock);
6214
6215 if (btrfs_test_opt(root->fs_info, SPACE_CACHE) &&
6216 cache->disk_cache_state < BTRFS_DC_CLEAR)
6217 cache->disk_cache_state = BTRFS_DC_CLEAR;
6218
6219 old_val = btrfs_block_group_used(&cache->item);
6220 num_bytes = min(total, cache->key.offset - byte_in_group);
6221 if (alloc) {
6222 old_val += num_bytes;
6223 btrfs_set_block_group_used(&cache->item, old_val);
6224 cache->reserved -= num_bytes;
6225 cache->space_info->bytes_reserved -= num_bytes;
6226 cache->space_info->bytes_used += num_bytes;
6227 cache->space_info->disk_used += num_bytes * factor;
6228 spin_unlock(&cache->lock);
6229 spin_unlock(&cache->space_info->lock);
6230 } else {
6231 old_val -= num_bytes;
6232 btrfs_set_block_group_used(&cache->item, old_val);
6233 cache->pinned += num_bytes;
6234 cache->space_info->bytes_pinned += num_bytes;
6235 cache->space_info->bytes_used -= num_bytes;
6236 cache->space_info->disk_used -= num_bytes * factor;
6237 spin_unlock(&cache->lock);
6238 spin_unlock(&cache->space_info->lock);
6239
6240 trace_btrfs_space_reservation(root->fs_info, "pinned",
6241 cache->space_info->flags,
6242 num_bytes, 1);
6243 set_extent_dirty(info->pinned_extents,
6244 bytenr, bytenr + num_bytes - 1,
6245 GFP_NOFS | __GFP_NOFAIL);
6246 }
6247
6248 spin_lock(&trans->transaction->dirty_bgs_lock);
6249 if (list_empty(&cache->dirty_list)) {
6250 list_add_tail(&cache->dirty_list,
6251 &trans->transaction->dirty_bgs);
6252 trans->transaction->num_dirty_bgs++;
6253 btrfs_get_block_group(cache);
6254 }
6255 spin_unlock(&trans->transaction->dirty_bgs_lock);
6256
6257 /*
6258 * No longer have used bytes in this block group, queue it for
6259 * deletion. We do this after adding the block group to the
6260 * dirty list to avoid races between cleaner kthread and space
6261 * cache writeout.
6262 */
6263 if (!alloc && old_val == 0) {
6264 spin_lock(&info->unused_bgs_lock);
6265 if (list_empty(&cache->bg_list)) {
6266 btrfs_get_block_group(cache);
6267 list_add_tail(&cache->bg_list,
6268 &info->unused_bgs);
6269 }
6270 spin_unlock(&info->unused_bgs_lock);
6271 }
6272
6273 btrfs_put_block_group(cache);
6274 total -= num_bytes;
6275 bytenr += num_bytes;
6276 }
6277 return 0;
6278 }
6279
6280 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
6281 {
6282 struct btrfs_block_group_cache *cache;
6283 u64 bytenr;
6284
6285 spin_lock(&root->fs_info->block_group_cache_lock);
6286 bytenr = root->fs_info->first_logical_byte;
6287 spin_unlock(&root->fs_info->block_group_cache_lock);
6288
6289 if (bytenr < (u64)-1)
6290 return bytenr;
6291
6292 cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
6293 if (!cache)
6294 return 0;
6295
6296 bytenr = cache->key.objectid;
6297 btrfs_put_block_group(cache);
6298
6299 return bytenr;
6300 }
6301
6302 static int pin_down_extent(struct btrfs_root *root,
6303 struct btrfs_block_group_cache *cache,
6304 u64 bytenr, u64 num_bytes, int reserved)
6305 {
6306 spin_lock(&cache->space_info->lock);
6307 spin_lock(&cache->lock);
6308 cache->pinned += num_bytes;
6309 cache->space_info->bytes_pinned += num_bytes;
6310 if (reserved) {
6311 cache->reserved -= num_bytes;
6312 cache->space_info->bytes_reserved -= num_bytes;
6313 }
6314 spin_unlock(&cache->lock);
6315 spin_unlock(&cache->space_info->lock);
6316
6317 trace_btrfs_space_reservation(root->fs_info, "pinned",
6318 cache->space_info->flags, num_bytes, 1);
6319 set_extent_dirty(root->fs_info->pinned_extents, bytenr,
6320 bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
6321 return 0;
6322 }
6323
6324 /*
6325 * this function must be called within transaction
6326 */
6327 int btrfs_pin_extent(struct btrfs_root *root,
6328 u64 bytenr, u64 num_bytes, int reserved)
6329 {
6330 struct btrfs_block_group_cache *cache;
6331
6332 cache = btrfs_lookup_block_group(root->fs_info, bytenr);
6333 BUG_ON(!cache); /* Logic error */
6334
6335 pin_down_extent(root, cache, bytenr, num_bytes, reserved);
6336
6337 btrfs_put_block_group(cache);
6338 return 0;
6339 }
6340
6341 /*
6342 * this function must be called within transaction
6343 */
6344 int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
6345 u64 bytenr, u64 num_bytes)
6346 {
6347 struct btrfs_block_group_cache *cache;
6348 int ret;
6349
6350 cache = btrfs_lookup_block_group(root->fs_info, bytenr);
6351 if (!cache)
6352 return -EINVAL;
6353
6354 /*
6355 * pull in the free space cache (if any) so that our pin
6356 * removes the free space from the cache. We have load_only set
6357 * to one because the slow code to read in the free extents does check
6358 * the pinned extents.
6359 */
6360 cache_block_group(cache, 1);
6361
6362 pin_down_extent(root, cache, bytenr, num_bytes, 0);
6363
6364 /* remove us from the free space cache (if we're there at all) */
6365 ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
6366 btrfs_put_block_group(cache);
6367 return ret;
6368 }
6369
6370 static int __exclude_logged_extent(struct btrfs_root *root, u64 start, u64 num_bytes)
6371 {
6372 int ret;
6373 struct btrfs_block_group_cache *block_group;
6374 struct btrfs_caching_control *caching_ctl;
6375
6376 block_group = btrfs_lookup_block_group(root->fs_info, start);
6377 if (!block_group)
6378 return -EINVAL;
6379
6380 cache_block_group(block_group, 0);
6381 caching_ctl = get_caching_control(block_group);
6382
6383 if (!caching_ctl) {
6384 /* Logic error */
6385 BUG_ON(!block_group_cache_done(block_group));
6386 ret = btrfs_remove_free_space(block_group, start, num_bytes);
6387 } else {
6388 mutex_lock(&caching_ctl->mutex);
6389
6390 if (start >= caching_ctl->progress) {
6391 ret = add_excluded_extent(root, start, num_bytes);
6392 } else if (start + num_bytes <= caching_ctl->progress) {
6393 ret = btrfs_remove_free_space(block_group,
6394 start, num_bytes);
6395 } else {
6396 num_bytes = caching_ctl->progress - start;
6397 ret = btrfs_remove_free_space(block_group,
6398 start, num_bytes);
6399 if (ret)
6400 goto out_lock;
6401
6402 num_bytes = (start + num_bytes) -
6403 caching_ctl->progress;
6404 start = caching_ctl->progress;
6405 ret = add_excluded_extent(root, start, num_bytes);
6406 }
6407 out_lock:
6408 mutex_unlock(&caching_ctl->mutex);
6409 put_caching_control(caching_ctl);
6410 }
6411 btrfs_put_block_group(block_group);
6412 return ret;
6413 }
6414
6415 int btrfs_exclude_logged_extents(struct btrfs_root *log,
6416 struct extent_buffer *eb)
6417 {
6418 struct btrfs_file_extent_item *item;
6419 struct btrfs_key key;
6420 int found_type;
6421 int i;
6422
6423 if (!btrfs_fs_incompat(log->fs_info, MIXED_GROUPS))
6424 return 0;
6425
6426 for (i = 0; i < btrfs_header_nritems(eb); i++) {
6427 btrfs_item_key_to_cpu(eb, &key, i);
6428 if (key.type != BTRFS_EXTENT_DATA_KEY)
6429 continue;
6430 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
6431 found_type = btrfs_file_extent_type(eb, item);
6432 if (found_type == BTRFS_FILE_EXTENT_INLINE)
6433 continue;
6434 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
6435 continue;
6436 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
6437 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
6438 __exclude_logged_extent(log, key.objectid, key.offset);
6439 }
6440
6441 return 0;
6442 }
6443
6444 static void
6445 btrfs_inc_block_group_reservations(struct btrfs_block_group_cache *bg)
6446 {
6447 atomic_inc(&bg->reservations);
6448 }
6449
6450 void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
6451 const u64 start)
6452 {
6453 struct btrfs_block_group_cache *bg;
6454
6455 bg = btrfs_lookup_block_group(fs_info, start);
6456 ASSERT(bg);
6457 if (atomic_dec_and_test(&bg->reservations))
6458 wake_up_atomic_t(&bg->reservations);
6459 btrfs_put_block_group(bg);
6460 }
6461
6462 static int btrfs_wait_bg_reservations_atomic_t(atomic_t *a)
6463 {
6464 schedule();
6465 return 0;
6466 }
6467
6468 void btrfs_wait_block_group_reservations(struct btrfs_block_group_cache *bg)
6469 {
6470 struct btrfs_space_info *space_info = bg->space_info;
6471
6472 ASSERT(bg->ro);
6473
6474 if (!(bg->flags & BTRFS_BLOCK_GROUP_DATA))
6475 return;
6476
6477 /*
6478 * Our block group is read only but before we set it to read only,
6479 * some task might have had allocated an extent from it already, but it
6480 * has not yet created a respective ordered extent (and added it to a
6481 * root's list of ordered extents).
6482 * Therefore wait for any task currently allocating extents, since the
6483 * block group's reservations counter is incremented while a read lock
6484 * on the groups' semaphore is held and decremented after releasing
6485 * the read access on that semaphore and creating the ordered extent.
6486 */
6487 down_write(&space_info->groups_sem);
6488 up_write(&space_info->groups_sem);
6489
6490 wait_on_atomic_t(&bg->reservations,
6491 btrfs_wait_bg_reservations_atomic_t,
6492 TASK_UNINTERRUPTIBLE);
6493 }
6494
6495 /**
6496 * btrfs_add_reserved_bytes - update the block_group and space info counters
6497 * @cache: The cache we are manipulating
6498 * @ram_bytes: The number of bytes of file content, and will be same to
6499 * @num_bytes except for the compress path.
6500 * @num_bytes: The number of bytes in question
6501 * @delalloc: The blocks are allocated for the delalloc write
6502 *
6503 * This is called by the allocator when it reserves space. Metadata
6504 * reservations should be called with RESERVE_ALLOC so we do the proper
6505 * ENOSPC accounting. For data we handle the reservation through clearing the
6506 * delalloc bits in the io_tree. We have to do this since we could end up
6507 * allocating less disk space for the amount of data we have reserved in the
6508 * case of compression.
6509 *
6510 * If this is a reservation and the block group has become read only we cannot
6511 * make the reservation and return -EAGAIN, otherwise this function always
6512 * succeeds.
6513 */
6514 static int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
6515 u64 ram_bytes, u64 num_bytes, int delalloc)
6516 {
6517 struct btrfs_space_info *space_info = cache->space_info;
6518 int ret = 0;
6519
6520 spin_lock(&space_info->lock);
6521 spin_lock(&cache->lock);
6522 if (cache->ro) {
6523 ret = -EAGAIN;
6524 } else {
6525 cache->reserved += num_bytes;
6526 space_info->bytes_reserved += num_bytes;
6527
6528 trace_btrfs_space_reservation(cache->fs_info,
6529 "space_info", space_info->flags,
6530 ram_bytes, 0);
6531 space_info->bytes_may_use -= ram_bytes;
6532 if (delalloc)
6533 cache->delalloc_bytes += num_bytes;
6534 }
6535 spin_unlock(&cache->lock);
6536 spin_unlock(&space_info->lock);
6537 return ret;
6538 }
6539
6540 /**
6541 * btrfs_free_reserved_bytes - update the block_group and space info counters
6542 * @cache: The cache we are manipulating
6543 * @num_bytes: The number of bytes in question
6544 * @delalloc: The blocks are allocated for the delalloc write
6545 *
6546 * This is called by somebody who is freeing space that was never actually used
6547 * on disk. For example if you reserve some space for a new leaf in transaction
6548 * A and before transaction A commits you free that leaf, you call this with
6549 * reserve set to 0 in order to clear the reservation.
6550 */
6551
6552 static int btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
6553 u64 num_bytes, int delalloc)
6554 {
6555 struct btrfs_space_info *space_info = cache->space_info;
6556 int ret = 0;
6557
6558 spin_lock(&space_info->lock);
6559 spin_lock(&cache->lock);
6560 if (cache->ro)
6561 space_info->bytes_readonly += num_bytes;
6562 cache->reserved -= num_bytes;
6563 space_info->bytes_reserved -= num_bytes;
6564
6565 if (delalloc)
6566 cache->delalloc_bytes -= num_bytes;
6567 spin_unlock(&cache->lock);
6568 spin_unlock(&space_info->lock);
6569 return ret;
6570 }
6571 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
6572 struct btrfs_root *root)
6573 {
6574 struct btrfs_fs_info *fs_info = root->fs_info;
6575 struct btrfs_caching_control *next;
6576 struct btrfs_caching_control *caching_ctl;
6577 struct btrfs_block_group_cache *cache;
6578
6579 down_write(&fs_info->commit_root_sem);
6580
6581 list_for_each_entry_safe(caching_ctl, next,
6582 &fs_info->caching_block_groups, list) {
6583 cache = caching_ctl->block_group;
6584 if (block_group_cache_done(cache)) {
6585 cache->last_byte_to_unpin = (u64)-1;
6586 list_del_init(&caching_ctl->list);
6587 put_caching_control(caching_ctl);
6588 } else {
6589 cache->last_byte_to_unpin = caching_ctl->progress;
6590 }
6591 }
6592
6593 if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6594 fs_info->pinned_extents = &fs_info->freed_extents[1];
6595 else
6596 fs_info->pinned_extents = &fs_info->freed_extents[0];
6597
6598 up_write(&fs_info->commit_root_sem);
6599
6600 update_global_block_rsv(fs_info);
6601 }
6602
6603 /*
6604 * Returns the free cluster for the given space info and sets empty_cluster to
6605 * what it should be based on the mount options.
6606 */
6607 static struct btrfs_free_cluster *
6608 fetch_cluster_info(struct btrfs_root *root, struct btrfs_space_info *space_info,
6609 u64 *empty_cluster)
6610 {
6611 struct btrfs_free_cluster *ret = NULL;
6612 bool ssd = btrfs_test_opt(root->fs_info, SSD);
6613
6614 *empty_cluster = 0;
6615 if (btrfs_mixed_space_info(space_info))
6616 return ret;
6617
6618 if (ssd)
6619 *empty_cluster = SZ_2M;
6620 if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
6621 ret = &root->fs_info->meta_alloc_cluster;
6622 if (!ssd)
6623 *empty_cluster = SZ_64K;
6624 } else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) && ssd) {
6625 ret = &root->fs_info->data_alloc_cluster;
6626 }
6627
6628 return ret;
6629 }
6630
6631 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end,
6632 const bool return_free_space)
6633 {
6634 struct btrfs_fs_info *fs_info = root->fs_info;
6635 struct btrfs_block_group_cache *cache = NULL;
6636 struct btrfs_space_info *space_info;
6637 struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
6638 struct btrfs_free_cluster *cluster = NULL;
6639 u64 len;
6640 u64 total_unpinned = 0;
6641 u64 empty_cluster = 0;
6642 bool readonly;
6643
6644 while (start <= end) {
6645 readonly = false;
6646 if (!cache ||
6647 start >= cache->key.objectid + cache->key.offset) {
6648 if (cache)
6649 btrfs_put_block_group(cache);
6650 total_unpinned = 0;
6651 cache = btrfs_lookup_block_group(fs_info, start);
6652 BUG_ON(!cache); /* Logic error */
6653
6654 cluster = fetch_cluster_info(root,
6655 cache->space_info,
6656 &empty_cluster);
6657 empty_cluster <<= 1;
6658 }
6659
6660 len = cache->key.objectid + cache->key.offset - start;
6661 len = min(len, end + 1 - start);
6662
6663 if (start < cache->last_byte_to_unpin) {
6664 len = min(len, cache->last_byte_to_unpin - start);
6665 if (return_free_space)
6666 btrfs_add_free_space(cache, start, len);
6667 }
6668
6669 start += len;
6670 total_unpinned += len;
6671 space_info = cache->space_info;
6672
6673 /*
6674 * If this space cluster has been marked as fragmented and we've
6675 * unpinned enough in this block group to potentially allow a
6676 * cluster to be created inside of it go ahead and clear the
6677 * fragmented check.
6678 */
6679 if (cluster && cluster->fragmented &&
6680 total_unpinned > empty_cluster) {
6681 spin_lock(&cluster->lock);
6682 cluster->fragmented = 0;
6683 spin_unlock(&cluster->lock);
6684 }
6685
6686 spin_lock(&space_info->lock);
6687 spin_lock(&cache->lock);
6688 cache->pinned -= len;
6689 space_info->bytes_pinned -= len;
6690
6691 trace_btrfs_space_reservation(fs_info, "pinned",
6692 space_info->flags, len, 0);
6693 space_info->max_extent_size = 0;
6694 percpu_counter_add(&space_info->total_bytes_pinned, -len);
6695 if (cache->ro) {
6696 space_info->bytes_readonly += len;
6697 readonly = true;
6698 }
6699 spin_unlock(&cache->lock);
6700 if (!readonly && return_free_space &&
6701 global_rsv->space_info == space_info) {
6702 u64 to_add = len;
6703 WARN_ON(!return_free_space);
6704 spin_lock(&global_rsv->lock);
6705 if (!global_rsv->full) {
6706 to_add = min(len, global_rsv->size -
6707 global_rsv->reserved);
6708 global_rsv->reserved += to_add;
6709 space_info->bytes_may_use += to_add;
6710 if (global_rsv->reserved >= global_rsv->size)
6711 global_rsv->full = 1;
6712 trace_btrfs_space_reservation(fs_info,
6713 "space_info",
6714 space_info->flags,
6715 to_add, 1);
6716 len -= to_add;
6717 }
6718 spin_unlock(&global_rsv->lock);
6719 /* Add to any tickets we may have */
6720 if (len)
6721 space_info_add_new_bytes(fs_info, space_info,
6722 len);
6723 }
6724 spin_unlock(&space_info->lock);
6725 }
6726
6727 if (cache)
6728 btrfs_put_block_group(cache);
6729 return 0;
6730 }
6731
6732 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
6733 struct btrfs_root *root)
6734 {
6735 struct btrfs_fs_info *fs_info = root->fs_info;
6736 struct btrfs_block_group_cache *block_group, *tmp;
6737 struct list_head *deleted_bgs;
6738 struct extent_io_tree *unpin;
6739 u64 start;
6740 u64 end;
6741 int ret;
6742
6743 if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6744 unpin = &fs_info->freed_extents[1];
6745 else
6746 unpin = &fs_info->freed_extents[0];
6747
6748 while (!trans->aborted) {
6749 mutex_lock(&fs_info->unused_bg_unpin_mutex);
6750 ret = find_first_extent_bit(unpin, 0, &start, &end,
6751 EXTENT_DIRTY, NULL);
6752 if (ret) {
6753 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6754 break;
6755 }
6756
6757 if (btrfs_test_opt(root->fs_info, DISCARD))
6758 ret = btrfs_discard_extent(root, start,
6759 end + 1 - start, NULL);
6760
6761 clear_extent_dirty(unpin, start, end);
6762 unpin_extent_range(root, start, end, true);
6763 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6764 cond_resched();
6765 }
6766
6767 /*
6768 * Transaction is finished. We don't need the lock anymore. We
6769 * do need to clean up the block groups in case of a transaction
6770 * abort.
6771 */
6772 deleted_bgs = &trans->transaction->deleted_bgs;
6773 list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
6774 u64 trimmed = 0;
6775
6776 ret = -EROFS;
6777 if (!trans->aborted)
6778 ret = btrfs_discard_extent(root,
6779 block_group->key.objectid,
6780 block_group->key.offset,
6781 &trimmed);
6782
6783 list_del_init(&block_group->bg_list);
6784 btrfs_put_block_group_trimming(block_group);
6785 btrfs_put_block_group(block_group);
6786
6787 if (ret) {
6788 const char *errstr = btrfs_decode_error(ret);
6789 btrfs_warn(fs_info,
6790 "Discard failed while removing blockgroup: errno=%d %s\n",
6791 ret, errstr);
6792 }
6793 }
6794
6795 return 0;
6796 }
6797
6798 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, u64 num_bytes,
6799 u64 owner, u64 root_objectid)
6800 {
6801 struct btrfs_space_info *space_info;
6802 u64 flags;
6803
6804 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6805 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
6806 flags = BTRFS_BLOCK_GROUP_SYSTEM;
6807 else
6808 flags = BTRFS_BLOCK_GROUP_METADATA;
6809 } else {
6810 flags = BTRFS_BLOCK_GROUP_DATA;
6811 }
6812
6813 space_info = __find_space_info(fs_info, flags);
6814 BUG_ON(!space_info); /* Logic bug */
6815 percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
6816 }
6817
6818
6819 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
6820 struct btrfs_root *root,
6821 struct btrfs_delayed_ref_node *node, u64 parent,
6822 u64 root_objectid, u64 owner_objectid,
6823 u64 owner_offset, int refs_to_drop,
6824 struct btrfs_delayed_extent_op *extent_op)
6825 {
6826 struct btrfs_key key;
6827 struct btrfs_path *path;
6828 struct btrfs_fs_info *info = root->fs_info;
6829 struct btrfs_root *extent_root = info->extent_root;
6830 struct extent_buffer *leaf;
6831 struct btrfs_extent_item *ei;
6832 struct btrfs_extent_inline_ref *iref;
6833 int ret;
6834 int is_data;
6835 int extent_slot = 0;
6836 int found_extent = 0;
6837 int num_to_del = 1;
6838 u32 item_size;
6839 u64 refs;
6840 u64 bytenr = node->bytenr;
6841 u64 num_bytes = node->num_bytes;
6842 int last_ref = 0;
6843 bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6844 SKINNY_METADATA);
6845
6846 path = btrfs_alloc_path();
6847 if (!path)
6848 return -ENOMEM;
6849
6850 path->reada = READA_FORWARD;
6851 path->leave_spinning = 1;
6852
6853 is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
6854 BUG_ON(!is_data && refs_to_drop != 1);
6855
6856 if (is_data)
6857 skinny_metadata = 0;
6858
6859 ret = lookup_extent_backref(trans, extent_root, path, &iref,
6860 bytenr, num_bytes, parent,
6861 root_objectid, owner_objectid,
6862 owner_offset);
6863 if (ret == 0) {
6864 extent_slot = path->slots[0];
6865 while (extent_slot >= 0) {
6866 btrfs_item_key_to_cpu(path->nodes[0], &key,
6867 extent_slot);
6868 if (key.objectid != bytenr)
6869 break;
6870 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
6871 key.offset == num_bytes) {
6872 found_extent = 1;
6873 break;
6874 }
6875 if (key.type == BTRFS_METADATA_ITEM_KEY &&
6876 key.offset == owner_objectid) {
6877 found_extent = 1;
6878 break;
6879 }
6880 if (path->slots[0] - extent_slot > 5)
6881 break;
6882 extent_slot--;
6883 }
6884 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6885 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
6886 if (found_extent && item_size < sizeof(*ei))
6887 found_extent = 0;
6888 #endif
6889 if (!found_extent) {
6890 BUG_ON(iref);
6891 ret = remove_extent_backref(trans, extent_root, path,
6892 NULL, refs_to_drop,
6893 is_data, &last_ref);
6894 if (ret) {
6895 btrfs_abort_transaction(trans, ret);
6896 goto out;
6897 }
6898 btrfs_release_path(path);
6899 path->leave_spinning = 1;
6900
6901 key.objectid = bytenr;
6902 key.type = BTRFS_EXTENT_ITEM_KEY;
6903 key.offset = num_bytes;
6904
6905 if (!is_data && skinny_metadata) {
6906 key.type = BTRFS_METADATA_ITEM_KEY;
6907 key.offset = owner_objectid;
6908 }
6909
6910 ret = btrfs_search_slot(trans, extent_root,
6911 &key, path, -1, 1);
6912 if (ret > 0 && skinny_metadata && path->slots[0]) {
6913 /*
6914 * Couldn't find our skinny metadata item,
6915 * see if we have ye olde extent item.
6916 */
6917 path->slots[0]--;
6918 btrfs_item_key_to_cpu(path->nodes[0], &key,
6919 path->slots[0]);
6920 if (key.objectid == bytenr &&
6921 key.type == BTRFS_EXTENT_ITEM_KEY &&
6922 key.offset == num_bytes)
6923 ret = 0;
6924 }
6925
6926 if (ret > 0 && skinny_metadata) {
6927 skinny_metadata = false;
6928 key.objectid = bytenr;
6929 key.type = BTRFS_EXTENT_ITEM_KEY;
6930 key.offset = num_bytes;
6931 btrfs_release_path(path);
6932 ret = btrfs_search_slot(trans, extent_root,
6933 &key, path, -1, 1);
6934 }
6935
6936 if (ret) {
6937 btrfs_err(info, "umm, got %d back from search, was looking for %llu",
6938 ret, bytenr);
6939 if (ret > 0)
6940 btrfs_print_leaf(extent_root,
6941 path->nodes[0]);
6942 }
6943 if (ret < 0) {
6944 btrfs_abort_transaction(trans, ret);
6945 goto out;
6946 }
6947 extent_slot = path->slots[0];
6948 }
6949 } else if (WARN_ON(ret == -ENOENT)) {
6950 btrfs_print_leaf(extent_root, path->nodes[0]);
6951 btrfs_err(info,
6952 "unable to find ref byte nr %llu parent %llu root %llu owner %llu offset %llu",
6953 bytenr, parent, root_objectid, owner_objectid,
6954 owner_offset);
6955 btrfs_abort_transaction(trans, ret);
6956 goto out;
6957 } else {
6958 btrfs_abort_transaction(trans, ret);
6959 goto out;
6960 }
6961
6962 leaf = path->nodes[0];
6963 item_size = btrfs_item_size_nr(leaf, extent_slot);
6964 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6965 if (item_size < sizeof(*ei)) {
6966 BUG_ON(found_extent || extent_slot != path->slots[0]);
6967 ret = convert_extent_item_v0(trans, extent_root, path,
6968 owner_objectid, 0);
6969 if (ret < 0) {
6970 btrfs_abort_transaction(trans, ret);
6971 goto out;
6972 }
6973
6974 btrfs_release_path(path);
6975 path->leave_spinning = 1;
6976
6977 key.objectid = bytenr;
6978 key.type = BTRFS_EXTENT_ITEM_KEY;
6979 key.offset = num_bytes;
6980
6981 ret = btrfs_search_slot(trans, extent_root, &key, path,
6982 -1, 1);
6983 if (ret) {
6984 btrfs_err(info, "umm, got %d back from search, was looking for %llu",
6985 ret, bytenr);
6986 btrfs_print_leaf(extent_root, path->nodes[0]);
6987 }
6988 if (ret < 0) {
6989 btrfs_abort_transaction(trans, ret);
6990 goto out;
6991 }
6992
6993 extent_slot = path->slots[0];
6994 leaf = path->nodes[0];
6995 item_size = btrfs_item_size_nr(leaf, extent_slot);
6996 }
6997 #endif
6998 BUG_ON(item_size < sizeof(*ei));
6999 ei = btrfs_item_ptr(leaf, extent_slot,
7000 struct btrfs_extent_item);
7001 if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
7002 key.type == BTRFS_EXTENT_ITEM_KEY) {
7003 struct btrfs_tree_block_info *bi;
7004 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
7005 bi = (struct btrfs_tree_block_info *)(ei + 1);
7006 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
7007 }
7008
7009 refs = btrfs_extent_refs(leaf, ei);
7010 if (refs < refs_to_drop) {
7011 btrfs_err(info, "trying to drop %d refs but we only have %Lu "
7012 "for bytenr %Lu", refs_to_drop, refs, bytenr);
7013 ret = -EINVAL;
7014 btrfs_abort_transaction(trans, ret);
7015 goto out;
7016 }
7017 refs -= refs_to_drop;
7018
7019 if (refs > 0) {
7020 if (extent_op)
7021 __run_delayed_extent_op(extent_op, leaf, ei);
7022 /*
7023 * In the case of inline back ref, reference count will
7024 * be updated by remove_extent_backref
7025 */
7026 if (iref) {
7027 BUG_ON(!found_extent);
7028 } else {
7029 btrfs_set_extent_refs(leaf, ei, refs);
7030 btrfs_mark_buffer_dirty(leaf);
7031 }
7032 if (found_extent) {
7033 ret = remove_extent_backref(trans, extent_root, path,
7034 iref, refs_to_drop,
7035 is_data, &last_ref);
7036 if (ret) {
7037 btrfs_abort_transaction(trans, ret);
7038 goto out;
7039 }
7040 }
7041 add_pinned_bytes(root->fs_info, -num_bytes, owner_objectid,
7042 root_objectid);
7043 } else {
7044 if (found_extent) {
7045 BUG_ON(is_data && refs_to_drop !=
7046 extent_data_ref_count(path, iref));
7047 if (iref) {
7048 BUG_ON(path->slots[0] != extent_slot);
7049 } else {
7050 BUG_ON(path->slots[0] != extent_slot + 1);
7051 path->slots[0] = extent_slot;
7052 num_to_del = 2;
7053 }
7054 }
7055
7056 last_ref = 1;
7057 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
7058 num_to_del);
7059 if (ret) {
7060 btrfs_abort_transaction(trans, ret);
7061 goto out;
7062 }
7063 btrfs_release_path(path);
7064
7065 if (is_data) {
7066 ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
7067 if (ret) {
7068 btrfs_abort_transaction(trans, ret);
7069 goto out;
7070 }
7071 }
7072
7073 ret = add_to_free_space_tree(trans, root->fs_info, bytenr,
7074 num_bytes);
7075 if (ret) {
7076 btrfs_abort_transaction(trans, ret);
7077 goto out;
7078 }
7079
7080 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
7081 if (ret) {
7082 btrfs_abort_transaction(trans, ret);
7083 goto out;
7084 }
7085 }
7086 btrfs_release_path(path);
7087
7088 out:
7089 btrfs_free_path(path);
7090 return ret;
7091 }
7092
7093 /*
7094 * when we free an block, it is possible (and likely) that we free the last
7095 * delayed ref for that extent as well. This searches the delayed ref tree for
7096 * a given extent, and if there are no other delayed refs to be processed, it
7097 * removes it from the tree.
7098 */
7099 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
7100 struct btrfs_root *root, u64 bytenr)
7101 {
7102 struct btrfs_delayed_ref_head *head;
7103 struct btrfs_delayed_ref_root *delayed_refs;
7104 int ret = 0;
7105
7106 delayed_refs = &trans->transaction->delayed_refs;
7107 spin_lock(&delayed_refs->lock);
7108 head = btrfs_find_delayed_ref_head(trans, bytenr);
7109 if (!head)
7110 goto out_delayed_unlock;
7111
7112 spin_lock(&head->lock);
7113 if (!list_empty(&head->ref_list))
7114 goto out;
7115
7116 if (head->extent_op) {
7117 if (!head->must_insert_reserved)
7118 goto out;
7119 btrfs_free_delayed_extent_op(head->extent_op);
7120 head->extent_op = NULL;
7121 }
7122
7123 /*
7124 * waiting for the lock here would deadlock. If someone else has it
7125 * locked they are already in the process of dropping it anyway
7126 */
7127 if (!mutex_trylock(&head->mutex))
7128 goto out;
7129
7130 /*
7131 * at this point we have a head with no other entries. Go
7132 * ahead and process it.
7133 */
7134 head->node.in_tree = 0;
7135 rb_erase(&head->href_node, &delayed_refs->href_root);
7136
7137 atomic_dec(&delayed_refs->num_entries);
7138
7139 /*
7140 * we don't take a ref on the node because we're removing it from the
7141 * tree, so we just steal the ref the tree was holding.
7142 */
7143 delayed_refs->num_heads--;
7144 if (head->processing == 0)
7145 delayed_refs->num_heads_ready--;
7146 head->processing = 0;
7147 spin_unlock(&head->lock);
7148 spin_unlock(&delayed_refs->lock);
7149
7150 BUG_ON(head->extent_op);
7151 if (head->must_insert_reserved)
7152 ret = 1;
7153
7154 mutex_unlock(&head->mutex);
7155 btrfs_put_delayed_ref(&head->node);
7156 return ret;
7157 out:
7158 spin_unlock(&head->lock);
7159
7160 out_delayed_unlock:
7161 spin_unlock(&delayed_refs->lock);
7162 return 0;
7163 }
7164
7165 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
7166 struct btrfs_root *root,
7167 struct extent_buffer *buf,
7168 u64 parent, int last_ref)
7169 {
7170 int pin = 1;
7171 int ret;
7172
7173 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7174 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
7175 buf->start, buf->len,
7176 parent, root->root_key.objectid,
7177 btrfs_header_level(buf),
7178 BTRFS_DROP_DELAYED_REF, NULL);
7179 BUG_ON(ret); /* -ENOMEM */
7180 }
7181
7182 if (!last_ref)
7183 return;
7184
7185 if (btrfs_header_generation(buf) == trans->transid) {
7186 struct btrfs_block_group_cache *cache;
7187
7188 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7189 ret = check_ref_cleanup(trans, root, buf->start);
7190 if (!ret)
7191 goto out;
7192 }
7193
7194 cache = btrfs_lookup_block_group(root->fs_info, buf->start);
7195
7196 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
7197 pin_down_extent(root, cache, buf->start, buf->len, 1);
7198 btrfs_put_block_group(cache);
7199 goto out;
7200 }
7201
7202 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
7203
7204 btrfs_add_free_space(cache, buf->start, buf->len);
7205 btrfs_free_reserved_bytes(cache, buf->len, 0);
7206 btrfs_put_block_group(cache);
7207 trace_btrfs_reserved_extent_free(root, buf->start, buf->len);
7208 pin = 0;
7209 }
7210 out:
7211 if (pin)
7212 add_pinned_bytes(root->fs_info, buf->len,
7213 btrfs_header_level(buf),
7214 root->root_key.objectid);
7215
7216 /*
7217 * Deleting the buffer, clear the corrupt flag since it doesn't matter
7218 * anymore.
7219 */
7220 clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
7221 }
7222
7223 /* Can return -ENOMEM */
7224 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
7225 u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
7226 u64 owner, u64 offset)
7227 {
7228 int ret;
7229 struct btrfs_fs_info *fs_info = root->fs_info;
7230
7231 if (btrfs_is_testing(fs_info))
7232 return 0;
7233
7234 add_pinned_bytes(root->fs_info, num_bytes, owner, root_objectid);
7235
7236 /*
7237 * tree log blocks never actually go into the extent allocation
7238 * tree, just update pinning info and exit early.
7239 */
7240 if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
7241 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
7242 /* unlocks the pinned mutex */
7243 btrfs_pin_extent(root, bytenr, num_bytes, 1);
7244 ret = 0;
7245 } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
7246 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
7247 num_bytes,
7248 parent, root_objectid, (int)owner,
7249 BTRFS_DROP_DELAYED_REF, NULL);
7250 } else {
7251 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
7252 num_bytes,
7253 parent, root_objectid, owner,
7254 offset, 0,
7255 BTRFS_DROP_DELAYED_REF, NULL);
7256 }
7257 return ret;
7258 }
7259
7260 /*
7261 * when we wait for progress in the block group caching, its because
7262 * our allocation attempt failed at least once. So, we must sleep
7263 * and let some progress happen before we try again.
7264 *
7265 * This function will sleep at least once waiting for new free space to
7266 * show up, and then it will check the block group free space numbers
7267 * for our min num_bytes. Another option is to have it go ahead
7268 * and look in the rbtree for a free extent of a given size, but this
7269 * is a good start.
7270 *
7271 * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
7272 * any of the information in this block group.
7273 */
7274 static noinline void
7275 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
7276 u64 num_bytes)
7277 {
7278 struct btrfs_caching_control *caching_ctl;
7279
7280 caching_ctl = get_caching_control(cache);
7281 if (!caching_ctl)
7282 return;
7283
7284 wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
7285 (cache->free_space_ctl->free_space >= num_bytes));
7286
7287 put_caching_control(caching_ctl);
7288 }
7289
7290 static noinline int
7291 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
7292 {
7293 struct btrfs_caching_control *caching_ctl;
7294 int ret = 0;
7295
7296 caching_ctl = get_caching_control(cache);
7297 if (!caching_ctl)
7298 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
7299
7300 wait_event(caching_ctl->wait, block_group_cache_done(cache));
7301 if (cache->cached == BTRFS_CACHE_ERROR)
7302 ret = -EIO;
7303 put_caching_control(caching_ctl);
7304 return ret;
7305 }
7306
7307 int __get_raid_index(u64 flags)
7308 {
7309 if (flags & BTRFS_BLOCK_GROUP_RAID10)
7310 return BTRFS_RAID_RAID10;
7311 else if (flags & BTRFS_BLOCK_GROUP_RAID1)
7312 return BTRFS_RAID_RAID1;
7313 else if (flags & BTRFS_BLOCK_GROUP_DUP)
7314 return BTRFS_RAID_DUP;
7315 else if (flags & BTRFS_BLOCK_GROUP_RAID0)
7316 return BTRFS_RAID_RAID0;
7317 else if (flags & BTRFS_BLOCK_GROUP_RAID5)
7318 return BTRFS_RAID_RAID5;
7319 else if (flags & BTRFS_BLOCK_GROUP_RAID6)
7320 return BTRFS_RAID_RAID6;
7321
7322 return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
7323 }
7324
7325 int get_block_group_index(struct btrfs_block_group_cache *cache)
7326 {
7327 return __get_raid_index(cache->flags);
7328 }
7329
7330 static const char *btrfs_raid_type_names[BTRFS_NR_RAID_TYPES] = {
7331 [BTRFS_RAID_RAID10] = "raid10",
7332 [BTRFS_RAID_RAID1] = "raid1",
7333 [BTRFS_RAID_DUP] = "dup",
7334 [BTRFS_RAID_RAID0] = "raid0",
7335 [BTRFS_RAID_SINGLE] = "single",
7336 [BTRFS_RAID_RAID5] = "raid5",
7337 [BTRFS_RAID_RAID6] = "raid6",
7338 };
7339
7340 static const char *get_raid_name(enum btrfs_raid_types type)
7341 {
7342 if (type >= BTRFS_NR_RAID_TYPES)
7343 return NULL;
7344
7345 return btrfs_raid_type_names[type];
7346 }
7347
7348 enum btrfs_loop_type {
7349 LOOP_CACHING_NOWAIT = 0,
7350 LOOP_CACHING_WAIT = 1,
7351 LOOP_ALLOC_CHUNK = 2,
7352 LOOP_NO_EMPTY_SIZE = 3,
7353 };
7354
7355 static inline void
7356 btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
7357 int delalloc)
7358 {
7359 if (delalloc)
7360 down_read(&cache->data_rwsem);
7361 }
7362
7363 static inline void
7364 btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
7365 int delalloc)
7366 {
7367 btrfs_get_block_group(cache);
7368 if (delalloc)
7369 down_read(&cache->data_rwsem);
7370 }
7371
7372 static struct btrfs_block_group_cache *
7373 btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
7374 struct btrfs_free_cluster *cluster,
7375 int delalloc)
7376 {
7377 struct btrfs_block_group_cache *used_bg = NULL;
7378
7379 spin_lock(&cluster->refill_lock);
7380 while (1) {
7381 used_bg = cluster->block_group;
7382 if (!used_bg)
7383 return NULL;
7384
7385 if (used_bg == block_group)
7386 return used_bg;
7387
7388 btrfs_get_block_group(used_bg);
7389
7390 if (!delalloc)
7391 return used_bg;
7392
7393 if (down_read_trylock(&used_bg->data_rwsem))
7394 return used_bg;
7395
7396 spin_unlock(&cluster->refill_lock);
7397
7398 down_read(&used_bg->data_rwsem);
7399
7400 spin_lock(&cluster->refill_lock);
7401 if (used_bg == cluster->block_group)
7402 return used_bg;
7403
7404 up_read(&used_bg->data_rwsem);
7405 btrfs_put_block_group(used_bg);
7406 }
7407 }
7408
7409 static inline void
7410 btrfs_release_block_group(struct btrfs_block_group_cache *cache,
7411 int delalloc)
7412 {
7413 if (delalloc)
7414 up_read(&cache->data_rwsem);
7415 btrfs_put_block_group(cache);
7416 }
7417
7418 /*
7419 * walks the btree of allocated extents and find a hole of a given size.
7420 * The key ins is changed to record the hole:
7421 * ins->objectid == start position
7422 * ins->flags = BTRFS_EXTENT_ITEM_KEY
7423 * ins->offset == the size of the hole.
7424 * Any available blocks before search_start are skipped.
7425 *
7426 * If there is no suitable free space, we will record the max size of
7427 * the free space extent currently.
7428 */
7429 static noinline int find_free_extent(struct btrfs_root *orig_root,
7430 u64 ram_bytes, u64 num_bytes, u64 empty_size,
7431 u64 hint_byte, struct btrfs_key *ins,
7432 u64 flags, int delalloc)
7433 {
7434 int ret = 0;
7435 struct btrfs_root *root = orig_root->fs_info->extent_root;
7436 struct btrfs_free_cluster *last_ptr = NULL;
7437 struct btrfs_block_group_cache *block_group = NULL;
7438 u64 search_start = 0;
7439 u64 max_extent_size = 0;
7440 u64 empty_cluster = 0;
7441 struct btrfs_space_info *space_info;
7442 int loop = 0;
7443 int index = __get_raid_index(flags);
7444 bool failed_cluster_refill = false;
7445 bool failed_alloc = false;
7446 bool use_cluster = true;
7447 bool have_caching_bg = false;
7448 bool orig_have_caching_bg = false;
7449 bool full_search = false;
7450
7451 WARN_ON(num_bytes < root->sectorsize);
7452 ins->type = BTRFS_EXTENT_ITEM_KEY;
7453 ins->objectid = 0;
7454 ins->offset = 0;
7455
7456 trace_find_free_extent(orig_root, num_bytes, empty_size, flags);
7457
7458 space_info = __find_space_info(root->fs_info, flags);
7459 if (!space_info) {
7460 btrfs_err(root->fs_info, "No space info for %llu", flags);
7461 return -ENOSPC;
7462 }
7463
7464 /*
7465 * If our free space is heavily fragmented we may not be able to make
7466 * big contiguous allocations, so instead of doing the expensive search
7467 * for free space, simply return ENOSPC with our max_extent_size so we
7468 * can go ahead and search for a more manageable chunk.
7469 *
7470 * If our max_extent_size is large enough for our allocation simply
7471 * disable clustering since we will likely not be able to find enough
7472 * space to create a cluster and induce latency trying.
7473 */
7474 if (unlikely(space_info->max_extent_size)) {
7475 spin_lock(&space_info->lock);
7476 if (space_info->max_extent_size &&
7477 num_bytes > space_info->max_extent_size) {
7478 ins->offset = space_info->max_extent_size;
7479 spin_unlock(&space_info->lock);
7480 return -ENOSPC;
7481 } else if (space_info->max_extent_size) {
7482 use_cluster = false;
7483 }
7484 spin_unlock(&space_info->lock);
7485 }
7486
7487 last_ptr = fetch_cluster_info(orig_root, space_info, &empty_cluster);
7488 if (last_ptr) {
7489 spin_lock(&last_ptr->lock);
7490 if (last_ptr->block_group)
7491 hint_byte = last_ptr->window_start;
7492 if (last_ptr->fragmented) {
7493 /*
7494 * We still set window_start so we can keep track of the
7495 * last place we found an allocation to try and save
7496 * some time.
7497 */
7498 hint_byte = last_ptr->window_start;
7499 use_cluster = false;
7500 }
7501 spin_unlock(&last_ptr->lock);
7502 }
7503
7504 search_start = max(search_start, first_logical_byte(root, 0));
7505 search_start = max(search_start, hint_byte);
7506 if (search_start == hint_byte) {
7507 block_group = btrfs_lookup_block_group(root->fs_info,
7508 search_start);
7509 /*
7510 * we don't want to use the block group if it doesn't match our
7511 * allocation bits, or if its not cached.
7512 *
7513 * However if we are re-searching with an ideal block group
7514 * picked out then we don't care that the block group is cached.
7515 */
7516 if (block_group && block_group_bits(block_group, flags) &&
7517 block_group->cached != BTRFS_CACHE_NO) {
7518 down_read(&space_info->groups_sem);
7519 if (list_empty(&block_group->list) ||
7520 block_group->ro) {
7521 /*
7522 * someone is removing this block group,
7523 * we can't jump into the have_block_group
7524 * target because our list pointers are not
7525 * valid
7526 */
7527 btrfs_put_block_group(block_group);
7528 up_read(&space_info->groups_sem);
7529 } else {
7530 index = get_block_group_index(block_group);
7531 btrfs_lock_block_group(block_group, delalloc);
7532 goto have_block_group;
7533 }
7534 } else if (block_group) {
7535 btrfs_put_block_group(block_group);
7536 }
7537 }
7538 search:
7539 have_caching_bg = false;
7540 if (index == 0 || index == __get_raid_index(flags))
7541 full_search = true;
7542 down_read(&space_info->groups_sem);
7543 list_for_each_entry(block_group, &space_info->block_groups[index],
7544 list) {
7545 u64 offset;
7546 int cached;
7547
7548 btrfs_grab_block_group(block_group, delalloc);
7549 search_start = block_group->key.objectid;
7550
7551 /*
7552 * this can happen if we end up cycling through all the
7553 * raid types, but we want to make sure we only allocate
7554 * for the proper type.
7555 */
7556 if (!block_group_bits(block_group, flags)) {
7557 u64 extra = BTRFS_BLOCK_GROUP_DUP |
7558 BTRFS_BLOCK_GROUP_RAID1 |
7559 BTRFS_BLOCK_GROUP_RAID5 |
7560 BTRFS_BLOCK_GROUP_RAID6 |
7561 BTRFS_BLOCK_GROUP_RAID10;
7562
7563 /*
7564 * if they asked for extra copies and this block group
7565 * doesn't provide them, bail. This does allow us to
7566 * fill raid0 from raid1.
7567 */
7568 if ((flags & extra) && !(block_group->flags & extra))
7569 goto loop;
7570 }
7571
7572 have_block_group:
7573 cached = block_group_cache_done(block_group);
7574 if (unlikely(!cached)) {
7575 have_caching_bg = true;
7576 ret = cache_block_group(block_group, 0);
7577 BUG_ON(ret < 0);
7578 ret = 0;
7579 }
7580
7581 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
7582 goto loop;
7583 if (unlikely(block_group->ro))
7584 goto loop;
7585
7586 /*
7587 * Ok we want to try and use the cluster allocator, so
7588 * lets look there
7589 */
7590 if (last_ptr && use_cluster) {
7591 struct btrfs_block_group_cache *used_block_group;
7592 unsigned long aligned_cluster;
7593 /*
7594 * the refill lock keeps out other
7595 * people trying to start a new cluster
7596 */
7597 used_block_group = btrfs_lock_cluster(block_group,
7598 last_ptr,
7599 delalloc);
7600 if (!used_block_group)
7601 goto refill_cluster;
7602
7603 if (used_block_group != block_group &&
7604 (used_block_group->ro ||
7605 !block_group_bits(used_block_group, flags)))
7606 goto release_cluster;
7607
7608 offset = btrfs_alloc_from_cluster(used_block_group,
7609 last_ptr,
7610 num_bytes,
7611 used_block_group->key.objectid,
7612 &max_extent_size);
7613 if (offset) {
7614 /* we have a block, we're done */
7615 spin_unlock(&last_ptr->refill_lock);
7616 trace_btrfs_reserve_extent_cluster(root,
7617 used_block_group,
7618 search_start, num_bytes);
7619 if (used_block_group != block_group) {
7620 btrfs_release_block_group(block_group,
7621 delalloc);
7622 block_group = used_block_group;
7623 }
7624 goto checks;
7625 }
7626
7627 WARN_ON(last_ptr->block_group != used_block_group);
7628 release_cluster:
7629 /* If we are on LOOP_NO_EMPTY_SIZE, we can't
7630 * set up a new clusters, so lets just skip it
7631 * and let the allocator find whatever block
7632 * it can find. If we reach this point, we
7633 * will have tried the cluster allocator
7634 * plenty of times and not have found
7635 * anything, so we are likely way too
7636 * fragmented for the clustering stuff to find
7637 * anything.
7638 *
7639 * However, if the cluster is taken from the
7640 * current block group, release the cluster
7641 * first, so that we stand a better chance of
7642 * succeeding in the unclustered
7643 * allocation. */
7644 if (loop >= LOOP_NO_EMPTY_SIZE &&
7645 used_block_group != block_group) {
7646 spin_unlock(&last_ptr->refill_lock);
7647 btrfs_release_block_group(used_block_group,
7648 delalloc);
7649 goto unclustered_alloc;
7650 }
7651
7652 /*
7653 * this cluster didn't work out, free it and
7654 * start over
7655 */
7656 btrfs_return_cluster_to_free_space(NULL, last_ptr);
7657
7658 if (used_block_group != block_group)
7659 btrfs_release_block_group(used_block_group,
7660 delalloc);
7661 refill_cluster:
7662 if (loop >= LOOP_NO_EMPTY_SIZE) {
7663 spin_unlock(&last_ptr->refill_lock);
7664 goto unclustered_alloc;
7665 }
7666
7667 aligned_cluster = max_t(unsigned long,
7668 empty_cluster + empty_size,
7669 block_group->full_stripe_len);
7670
7671 /* allocate a cluster in this block group */
7672 ret = btrfs_find_space_cluster(root, block_group,
7673 last_ptr, search_start,
7674 num_bytes,
7675 aligned_cluster);
7676 if (ret == 0) {
7677 /*
7678 * now pull our allocation out of this
7679 * cluster
7680 */
7681 offset = btrfs_alloc_from_cluster(block_group,
7682 last_ptr,
7683 num_bytes,
7684 search_start,
7685 &max_extent_size);
7686 if (offset) {
7687 /* we found one, proceed */
7688 spin_unlock(&last_ptr->refill_lock);
7689 trace_btrfs_reserve_extent_cluster(root,
7690 block_group, search_start,
7691 num_bytes);
7692 goto checks;
7693 }
7694 } else if (!cached && loop > LOOP_CACHING_NOWAIT
7695 && !failed_cluster_refill) {
7696 spin_unlock(&last_ptr->refill_lock);
7697
7698 failed_cluster_refill = true;
7699 wait_block_group_cache_progress(block_group,
7700 num_bytes + empty_cluster + empty_size);
7701 goto have_block_group;
7702 }
7703
7704 /*
7705 * at this point we either didn't find a cluster
7706 * or we weren't able to allocate a block from our
7707 * cluster. Free the cluster we've been trying
7708 * to use, and go to the next block group
7709 */
7710 btrfs_return_cluster_to_free_space(NULL, last_ptr);
7711 spin_unlock(&last_ptr->refill_lock);
7712 goto loop;
7713 }
7714
7715 unclustered_alloc:
7716 /*
7717 * We are doing an unclustered alloc, set the fragmented flag so
7718 * we don't bother trying to setup a cluster again until we get
7719 * more space.
7720 */
7721 if (unlikely(last_ptr)) {
7722 spin_lock(&last_ptr->lock);
7723 last_ptr->fragmented = 1;
7724 spin_unlock(&last_ptr->lock);
7725 }
7726 spin_lock(&block_group->free_space_ctl->tree_lock);
7727 if (cached &&
7728 block_group->free_space_ctl->free_space <
7729 num_bytes + empty_cluster + empty_size) {
7730 if (block_group->free_space_ctl->free_space >
7731 max_extent_size)
7732 max_extent_size =
7733 block_group->free_space_ctl->free_space;
7734 spin_unlock(&block_group->free_space_ctl->tree_lock);
7735 goto loop;
7736 }
7737 spin_unlock(&block_group->free_space_ctl->tree_lock);
7738
7739 offset = btrfs_find_space_for_alloc(block_group, search_start,
7740 num_bytes, empty_size,
7741 &max_extent_size);
7742 /*
7743 * If we didn't find a chunk, and we haven't failed on this
7744 * block group before, and this block group is in the middle of
7745 * caching and we are ok with waiting, then go ahead and wait
7746 * for progress to be made, and set failed_alloc to true.
7747 *
7748 * If failed_alloc is true then we've already waited on this
7749 * block group once and should move on to the next block group.
7750 */
7751 if (!offset && !failed_alloc && !cached &&
7752 loop > LOOP_CACHING_NOWAIT) {
7753 wait_block_group_cache_progress(block_group,
7754 num_bytes + empty_size);
7755 failed_alloc = true;
7756 goto have_block_group;
7757 } else if (!offset) {
7758 goto loop;
7759 }
7760 checks:
7761 search_start = ALIGN(offset, root->stripesize);
7762
7763 /* move on to the next group */
7764 if (search_start + num_bytes >
7765 block_group->key.objectid + block_group->key.offset) {
7766 btrfs_add_free_space(block_group, offset, num_bytes);
7767 goto loop;
7768 }
7769
7770 if (offset < search_start)
7771 btrfs_add_free_space(block_group, offset,
7772 search_start - offset);
7773 BUG_ON(offset > search_start);
7774
7775 ret = btrfs_add_reserved_bytes(block_group, ram_bytes,
7776 num_bytes, delalloc);
7777 if (ret == -EAGAIN) {
7778 btrfs_add_free_space(block_group, offset, num_bytes);
7779 goto loop;
7780 }
7781 btrfs_inc_block_group_reservations(block_group);
7782
7783 /* we are all good, lets return */
7784 ins->objectid = search_start;
7785 ins->offset = num_bytes;
7786
7787 trace_btrfs_reserve_extent(orig_root, block_group,
7788 search_start, num_bytes);
7789 btrfs_release_block_group(block_group, delalloc);
7790 break;
7791 loop:
7792 failed_cluster_refill = false;
7793 failed_alloc = false;
7794 BUG_ON(index != get_block_group_index(block_group));
7795 btrfs_release_block_group(block_group, delalloc);
7796 }
7797 up_read(&space_info->groups_sem);
7798
7799 if ((loop == LOOP_CACHING_NOWAIT) && have_caching_bg
7800 && !orig_have_caching_bg)
7801 orig_have_caching_bg = true;
7802
7803 if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
7804 goto search;
7805
7806 if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
7807 goto search;
7808
7809 /*
7810 * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
7811 * caching kthreads as we move along
7812 * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
7813 * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
7814 * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
7815 * again
7816 */
7817 if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
7818 index = 0;
7819 if (loop == LOOP_CACHING_NOWAIT) {
7820 /*
7821 * We want to skip the LOOP_CACHING_WAIT step if we
7822 * don't have any uncached bgs and we've already done a
7823 * full search through.
7824 */
7825 if (orig_have_caching_bg || !full_search)
7826 loop = LOOP_CACHING_WAIT;
7827 else
7828 loop = LOOP_ALLOC_CHUNK;
7829 } else {
7830 loop++;
7831 }
7832
7833 if (loop == LOOP_ALLOC_CHUNK) {
7834 struct btrfs_trans_handle *trans;
7835 int exist = 0;
7836
7837 trans = current->journal_info;
7838 if (trans)
7839 exist = 1;
7840 else
7841 trans = btrfs_join_transaction(root);
7842
7843 if (IS_ERR(trans)) {
7844 ret = PTR_ERR(trans);
7845 goto out;
7846 }
7847
7848 ret = do_chunk_alloc(trans, root, flags,
7849 CHUNK_ALLOC_FORCE);
7850
7851 /*
7852 * If we can't allocate a new chunk we've already looped
7853 * through at least once, move on to the NO_EMPTY_SIZE
7854 * case.
7855 */
7856 if (ret == -ENOSPC)
7857 loop = LOOP_NO_EMPTY_SIZE;
7858
7859 /*
7860 * Do not bail out on ENOSPC since we
7861 * can do more things.
7862 */
7863 if (ret < 0 && ret != -ENOSPC)
7864 btrfs_abort_transaction(trans, ret);
7865 else
7866 ret = 0;
7867 if (!exist)
7868 btrfs_end_transaction(trans, root);
7869 if (ret)
7870 goto out;
7871 }
7872
7873 if (loop == LOOP_NO_EMPTY_SIZE) {
7874 /*
7875 * Don't loop again if we already have no empty_size and
7876 * no empty_cluster.
7877 */
7878 if (empty_size == 0 &&
7879 empty_cluster == 0) {
7880 ret = -ENOSPC;
7881 goto out;
7882 }
7883 empty_size = 0;
7884 empty_cluster = 0;
7885 }
7886
7887 goto search;
7888 } else if (!ins->objectid) {
7889 ret = -ENOSPC;
7890 } else if (ins->objectid) {
7891 if (!use_cluster && last_ptr) {
7892 spin_lock(&last_ptr->lock);
7893 last_ptr->window_start = ins->objectid;
7894 spin_unlock(&last_ptr->lock);
7895 }
7896 ret = 0;
7897 }
7898 out:
7899 if (ret == -ENOSPC) {
7900 spin_lock(&space_info->lock);
7901 space_info->max_extent_size = max_extent_size;
7902 spin_unlock(&space_info->lock);
7903 ins->offset = max_extent_size;
7904 }
7905 return ret;
7906 }
7907
7908 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
7909 int dump_block_groups)
7910 {
7911 struct btrfs_block_group_cache *cache;
7912 int index = 0;
7913
7914 spin_lock(&info->lock);
7915 printk(KERN_INFO "BTRFS: space_info %llu has %llu free, is %sfull\n",
7916 info->flags,
7917 info->total_bytes - info->bytes_used - info->bytes_pinned -
7918 info->bytes_reserved - info->bytes_readonly -
7919 info->bytes_may_use, (info->full) ? "" : "not ");
7920 printk(KERN_INFO "BTRFS: space_info total=%llu, used=%llu, pinned=%llu, "
7921 "reserved=%llu, may_use=%llu, readonly=%llu\n",
7922 info->total_bytes, info->bytes_used, info->bytes_pinned,
7923 info->bytes_reserved, info->bytes_may_use,
7924 info->bytes_readonly);
7925 spin_unlock(&info->lock);
7926
7927 if (!dump_block_groups)
7928 return;
7929
7930 down_read(&info->groups_sem);
7931 again:
7932 list_for_each_entry(cache, &info->block_groups[index], list) {
7933 spin_lock(&cache->lock);
7934 printk(KERN_INFO "BTRFS: "
7935 "block group %llu has %llu bytes, "
7936 "%llu used %llu pinned %llu reserved %s\n",
7937 cache->key.objectid, cache->key.offset,
7938 btrfs_block_group_used(&cache->item), cache->pinned,
7939 cache->reserved, cache->ro ? "[readonly]" : "");
7940 btrfs_dump_free_space(cache, bytes);
7941 spin_unlock(&cache->lock);
7942 }
7943 if (++index < BTRFS_NR_RAID_TYPES)
7944 goto again;
7945 up_read(&info->groups_sem);
7946 }
7947
7948 int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes,
7949 u64 num_bytes, u64 min_alloc_size,
7950 u64 empty_size, u64 hint_byte,
7951 struct btrfs_key *ins, int is_data, int delalloc)
7952 {
7953 bool final_tried = num_bytes == min_alloc_size;
7954 u64 flags;
7955 int ret;
7956
7957 flags = btrfs_get_alloc_profile(root, is_data);
7958 again:
7959 WARN_ON(num_bytes < root->sectorsize);
7960 ret = find_free_extent(root, ram_bytes, num_bytes, empty_size,
7961 hint_byte, ins, flags, delalloc);
7962 if (!ret && !is_data) {
7963 btrfs_dec_block_group_reservations(root->fs_info,
7964 ins->objectid);
7965 } else if (ret == -ENOSPC) {
7966 if (!final_tried && ins->offset) {
7967 num_bytes = min(num_bytes >> 1, ins->offset);
7968 num_bytes = round_down(num_bytes, root->sectorsize);
7969 num_bytes = max(num_bytes, min_alloc_size);
7970 ram_bytes = num_bytes;
7971 if (num_bytes == min_alloc_size)
7972 final_tried = true;
7973 goto again;
7974 } else if (btrfs_test_opt(root->fs_info, ENOSPC_DEBUG)) {
7975 struct btrfs_space_info *sinfo;
7976
7977 sinfo = __find_space_info(root->fs_info, flags);
7978 btrfs_err(root->fs_info, "allocation failed flags %llu, wanted %llu",
7979 flags, num_bytes);
7980 if (sinfo)
7981 dump_space_info(sinfo, num_bytes, 1);
7982 }
7983 }
7984
7985 return ret;
7986 }
7987
7988 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
7989 u64 start, u64 len,
7990 int pin, int delalloc)
7991 {
7992 struct btrfs_block_group_cache *cache;
7993 int ret = 0;
7994
7995 cache = btrfs_lookup_block_group(root->fs_info, start);
7996 if (!cache) {
7997 btrfs_err(root->fs_info, "Unable to find block group for %llu",
7998 start);
7999 return -ENOSPC;
8000 }
8001
8002 if (pin)
8003 pin_down_extent(root, cache, start, len, 1);
8004 else {
8005 if (btrfs_test_opt(root->fs_info, DISCARD))
8006 ret = btrfs_discard_extent(root, start, len, NULL);
8007 btrfs_add_free_space(cache, start, len);
8008 btrfs_free_reserved_bytes(cache, len, delalloc);
8009 trace_btrfs_reserved_extent_free(root, start, len);
8010 }
8011
8012 btrfs_put_block_group(cache);
8013 return ret;
8014 }
8015
8016 int btrfs_free_reserved_extent(struct btrfs_root *root,
8017 u64 start, u64 len, int delalloc)
8018 {
8019 return __btrfs_free_reserved_extent(root, start, len, 0, delalloc);
8020 }
8021
8022 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
8023 u64 start, u64 len)
8024 {
8025 return __btrfs_free_reserved_extent(root, start, len, 1, 0);
8026 }
8027
8028 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8029 struct btrfs_root *root,
8030 u64 parent, u64 root_objectid,
8031 u64 flags, u64 owner, u64 offset,
8032 struct btrfs_key *ins, int ref_mod)
8033 {
8034 int ret;
8035 struct btrfs_fs_info *fs_info = root->fs_info;
8036 struct btrfs_extent_item *extent_item;
8037 struct btrfs_extent_inline_ref *iref;
8038 struct btrfs_path *path;
8039 struct extent_buffer *leaf;
8040 int type;
8041 u32 size;
8042
8043 if (parent > 0)
8044 type = BTRFS_SHARED_DATA_REF_KEY;
8045 else
8046 type = BTRFS_EXTENT_DATA_REF_KEY;
8047
8048 size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
8049
8050 path = btrfs_alloc_path();
8051 if (!path)
8052 return -ENOMEM;
8053
8054 path->leave_spinning = 1;
8055 ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
8056 ins, size);
8057 if (ret) {
8058 btrfs_free_path(path);
8059 return ret;
8060 }
8061
8062 leaf = path->nodes[0];
8063 extent_item = btrfs_item_ptr(leaf, path->slots[0],
8064 struct btrfs_extent_item);
8065 btrfs_set_extent_refs(leaf, extent_item, ref_mod);
8066 btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8067 btrfs_set_extent_flags(leaf, extent_item,
8068 flags | BTRFS_EXTENT_FLAG_DATA);
8069
8070 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8071 btrfs_set_extent_inline_ref_type(leaf, iref, type);
8072 if (parent > 0) {
8073 struct btrfs_shared_data_ref *ref;
8074 ref = (struct btrfs_shared_data_ref *)(iref + 1);
8075 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
8076 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
8077 } else {
8078 struct btrfs_extent_data_ref *ref;
8079 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
8080 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
8081 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
8082 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
8083 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
8084 }
8085
8086 btrfs_mark_buffer_dirty(path->nodes[0]);
8087 btrfs_free_path(path);
8088
8089 ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
8090 ins->offset);
8091 if (ret)
8092 return ret;
8093
8094 ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
8095 if (ret) { /* -ENOENT, logic error */
8096 btrfs_err(fs_info, "update block group failed for %llu %llu",
8097 ins->objectid, ins->offset);
8098 BUG();
8099 }
8100 trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
8101 return ret;
8102 }
8103
8104 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
8105 struct btrfs_root *root,
8106 u64 parent, u64 root_objectid,
8107 u64 flags, struct btrfs_disk_key *key,
8108 int level, struct btrfs_key *ins)
8109 {
8110 int ret;
8111 struct btrfs_fs_info *fs_info = root->fs_info;
8112 struct btrfs_extent_item *extent_item;
8113 struct btrfs_tree_block_info *block_info;
8114 struct btrfs_extent_inline_ref *iref;
8115 struct btrfs_path *path;
8116 struct extent_buffer *leaf;
8117 u32 size = sizeof(*extent_item) + sizeof(*iref);
8118 u64 num_bytes = ins->offset;
8119 bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
8120 SKINNY_METADATA);
8121
8122 if (!skinny_metadata)
8123 size += sizeof(*block_info);
8124
8125 path = btrfs_alloc_path();
8126 if (!path) {
8127 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
8128 root->nodesize);
8129 return -ENOMEM;
8130 }
8131
8132 path->leave_spinning = 1;
8133 ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
8134 ins, size);
8135 if (ret) {
8136 btrfs_free_path(path);
8137 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
8138 root->nodesize);
8139 return ret;
8140 }
8141
8142 leaf = path->nodes[0];
8143 extent_item = btrfs_item_ptr(leaf, path->slots[0],
8144 struct btrfs_extent_item);
8145 btrfs_set_extent_refs(leaf, extent_item, 1);
8146 btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8147 btrfs_set_extent_flags(leaf, extent_item,
8148 flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
8149
8150 if (skinny_metadata) {
8151 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8152 num_bytes = root->nodesize;
8153 } else {
8154 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
8155 btrfs_set_tree_block_key(leaf, block_info, key);
8156 btrfs_set_tree_block_level(leaf, block_info, level);
8157 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
8158 }
8159
8160 if (parent > 0) {
8161 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
8162 btrfs_set_extent_inline_ref_type(leaf, iref,
8163 BTRFS_SHARED_BLOCK_REF_KEY);
8164 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
8165 } else {
8166 btrfs_set_extent_inline_ref_type(leaf, iref,
8167 BTRFS_TREE_BLOCK_REF_KEY);
8168 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
8169 }
8170
8171 btrfs_mark_buffer_dirty(leaf);
8172 btrfs_free_path(path);
8173
8174 ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
8175 num_bytes);
8176 if (ret)
8177 return ret;
8178
8179 ret = update_block_group(trans, root, ins->objectid, root->nodesize,
8180 1);
8181 if (ret) { /* -ENOENT, logic error */
8182 btrfs_err(fs_info, "update block group failed for %llu %llu",
8183 ins->objectid, ins->offset);
8184 BUG();
8185 }
8186
8187 trace_btrfs_reserved_extent_alloc(root, ins->objectid, root->nodesize);
8188 return ret;
8189 }
8190
8191 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8192 struct btrfs_root *root,
8193 u64 root_objectid, u64 owner,
8194 u64 offset, u64 ram_bytes,
8195 struct btrfs_key *ins)
8196 {
8197 int ret;
8198
8199 BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
8200
8201 ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
8202 ins->offset, 0,
8203 root_objectid, owner, offset,
8204 ram_bytes, BTRFS_ADD_DELAYED_EXTENT,
8205 NULL);
8206 return ret;
8207 }
8208
8209 /*
8210 * this is used by the tree logging recovery code. It records that
8211 * an extent has been allocated and makes sure to clear the free
8212 * space cache bits as well
8213 */
8214 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
8215 struct btrfs_root *root,
8216 u64 root_objectid, u64 owner, u64 offset,
8217 struct btrfs_key *ins)
8218 {
8219 int ret;
8220 struct btrfs_block_group_cache *block_group;
8221
8222 /*
8223 * Mixed block groups will exclude before processing the log so we only
8224 * need to do the exclude dance if this fs isn't mixed.
8225 */
8226 if (!btrfs_fs_incompat(root->fs_info, MIXED_GROUPS)) {
8227 ret = __exclude_logged_extent(root, ins->objectid, ins->offset);
8228 if (ret)
8229 return ret;
8230 }
8231
8232 block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
8233 if (!block_group)
8234 return -EINVAL;
8235
8236 ret = btrfs_add_reserved_bytes(block_group, ins->offset,
8237 ins->offset, 0);
8238 BUG_ON(ret); /* logic error */
8239 ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
8240 0, owner, offset, ins, 1);
8241 btrfs_put_block_group(block_group);
8242 return ret;
8243 }
8244
8245 static struct extent_buffer *
8246 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
8247 u64 bytenr, int level)
8248 {
8249 struct extent_buffer *buf;
8250
8251 buf = btrfs_find_create_tree_block(root, bytenr);
8252 if (IS_ERR(buf))
8253 return buf;
8254
8255 btrfs_set_header_generation(buf, trans->transid);
8256 btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
8257 btrfs_tree_lock(buf);
8258 clean_tree_block(trans, root->fs_info, buf);
8259 clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
8260
8261 btrfs_set_lock_blocking(buf);
8262 set_extent_buffer_uptodate(buf);
8263
8264 if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
8265 buf->log_index = root->log_transid % 2;
8266 /*
8267 * we allow two log transactions at a time, use different
8268 * EXENT bit to differentiate dirty pages.
8269 */
8270 if (buf->log_index == 0)
8271 set_extent_dirty(&root->dirty_log_pages, buf->start,
8272 buf->start + buf->len - 1, GFP_NOFS);
8273 else
8274 set_extent_new(&root->dirty_log_pages, buf->start,
8275 buf->start + buf->len - 1);
8276 } else {
8277 buf->log_index = -1;
8278 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
8279 buf->start + buf->len - 1, GFP_NOFS);
8280 }
8281 trans->dirty = true;
8282 /* this returns a buffer locked for blocking */
8283 return buf;
8284 }
8285
8286 static struct btrfs_block_rsv *
8287 use_block_rsv(struct btrfs_trans_handle *trans,
8288 struct btrfs_root *root, u32 blocksize)
8289 {
8290 struct btrfs_block_rsv *block_rsv;
8291 struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
8292 int ret;
8293 bool global_updated = false;
8294
8295 block_rsv = get_block_rsv(trans, root);
8296
8297 if (unlikely(block_rsv->size == 0))
8298 goto try_reserve;
8299 again:
8300 ret = block_rsv_use_bytes(block_rsv, blocksize);
8301 if (!ret)
8302 return block_rsv;
8303
8304 if (block_rsv->failfast)
8305 return ERR_PTR(ret);
8306
8307 if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
8308 global_updated = true;
8309 update_global_block_rsv(root->fs_info);
8310 goto again;
8311 }
8312
8313 if (btrfs_test_opt(root->fs_info, ENOSPC_DEBUG)) {
8314 static DEFINE_RATELIMIT_STATE(_rs,
8315 DEFAULT_RATELIMIT_INTERVAL * 10,
8316 /*DEFAULT_RATELIMIT_BURST*/ 1);
8317 if (__ratelimit(&_rs))
8318 WARN(1, KERN_DEBUG
8319 "BTRFS: block rsv returned %d\n", ret);
8320 }
8321 try_reserve:
8322 ret = reserve_metadata_bytes(root, block_rsv, blocksize,
8323 BTRFS_RESERVE_NO_FLUSH);
8324 if (!ret)
8325 return block_rsv;
8326 /*
8327 * If we couldn't reserve metadata bytes try and use some from
8328 * the global reserve if its space type is the same as the global
8329 * reservation.
8330 */
8331 if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
8332 block_rsv->space_info == global_rsv->space_info) {
8333 ret = block_rsv_use_bytes(global_rsv, blocksize);
8334 if (!ret)
8335 return global_rsv;
8336 }
8337 return ERR_PTR(ret);
8338 }
8339
8340 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
8341 struct btrfs_block_rsv *block_rsv, u32 blocksize)
8342 {
8343 block_rsv_add_bytes(block_rsv, blocksize, 0);
8344 block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
8345 }
8346
8347 /*
8348 * finds a free extent and does all the dirty work required for allocation
8349 * returns the tree buffer or an ERR_PTR on error.
8350 */
8351 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
8352 struct btrfs_root *root,
8353 u64 parent, u64 root_objectid,
8354 struct btrfs_disk_key *key, int level,
8355 u64 hint, u64 empty_size)
8356 {
8357 struct btrfs_key ins;
8358 struct btrfs_block_rsv *block_rsv;
8359 struct extent_buffer *buf;
8360 struct btrfs_delayed_extent_op *extent_op;
8361 u64 flags = 0;
8362 int ret;
8363 u32 blocksize = root->nodesize;
8364 bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
8365 SKINNY_METADATA);
8366
8367 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
8368 if (btrfs_is_testing(root->fs_info)) {
8369 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
8370 level);
8371 if (!IS_ERR(buf))
8372 root->alloc_bytenr += blocksize;
8373 return buf;
8374 }
8375 #endif
8376
8377 block_rsv = use_block_rsv(trans, root, blocksize);
8378 if (IS_ERR(block_rsv))
8379 return ERR_CAST(block_rsv);
8380
8381 ret = btrfs_reserve_extent(root, blocksize, blocksize, blocksize,
8382 empty_size, hint, &ins, 0, 0);
8383 if (ret)
8384 goto out_unuse;
8385
8386 buf = btrfs_init_new_buffer(trans, root, ins.objectid, level);
8387 if (IS_ERR(buf)) {
8388 ret = PTR_ERR(buf);
8389 goto out_free_reserved;
8390 }
8391
8392 if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
8393 if (parent == 0)
8394 parent = ins.objectid;
8395 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
8396 } else
8397 BUG_ON(parent > 0);
8398
8399 if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
8400 extent_op = btrfs_alloc_delayed_extent_op();
8401 if (!extent_op) {
8402 ret = -ENOMEM;
8403 goto out_free_buf;
8404 }
8405 if (key)
8406 memcpy(&extent_op->key, key, sizeof(extent_op->key));
8407 else
8408 memset(&extent_op->key, 0, sizeof(extent_op->key));
8409 extent_op->flags_to_set = flags;
8410 extent_op->update_key = skinny_metadata ? false : true;
8411 extent_op->update_flags = true;
8412 extent_op->is_data = false;
8413 extent_op->level = level;
8414
8415 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
8416 ins.objectid, ins.offset,
8417 parent, root_objectid, level,
8418 BTRFS_ADD_DELAYED_EXTENT,
8419 extent_op);
8420 if (ret)
8421 goto out_free_delayed;
8422 }
8423 return buf;
8424
8425 out_free_delayed:
8426 btrfs_free_delayed_extent_op(extent_op);
8427 out_free_buf:
8428 free_extent_buffer(buf);
8429 out_free_reserved:
8430 btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 0);
8431 out_unuse:
8432 unuse_block_rsv(root->fs_info, block_rsv, blocksize);
8433 return ERR_PTR(ret);
8434 }
8435
8436 struct walk_control {
8437 u64 refs[BTRFS_MAX_LEVEL];
8438 u64 flags[BTRFS_MAX_LEVEL];
8439 struct btrfs_key update_progress;
8440 int stage;
8441 int level;
8442 int shared_level;
8443 int update_ref;
8444 int keep_locks;
8445 int reada_slot;
8446 int reada_count;
8447 int for_reloc;
8448 };
8449
8450 #define DROP_REFERENCE 1
8451 #define UPDATE_BACKREF 2
8452
8453 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
8454 struct btrfs_root *root,
8455 struct walk_control *wc,
8456 struct btrfs_path *path)
8457 {
8458 u64 bytenr;
8459 u64 generation;
8460 u64 refs;
8461 u64 flags;
8462 u32 nritems;
8463 u32 blocksize;
8464 struct btrfs_key key;
8465 struct extent_buffer *eb;
8466 int ret;
8467 int slot;
8468 int nread = 0;
8469
8470 if (path->slots[wc->level] < wc->reada_slot) {
8471 wc->reada_count = wc->reada_count * 2 / 3;
8472 wc->reada_count = max(wc->reada_count, 2);
8473 } else {
8474 wc->reada_count = wc->reada_count * 3 / 2;
8475 wc->reada_count = min_t(int, wc->reada_count,
8476 BTRFS_NODEPTRS_PER_BLOCK(root));
8477 }
8478
8479 eb = path->nodes[wc->level];
8480 nritems = btrfs_header_nritems(eb);
8481 blocksize = root->nodesize;
8482
8483 for (slot = path->slots[wc->level]; slot < nritems; slot++) {
8484 if (nread >= wc->reada_count)
8485 break;
8486
8487 cond_resched();
8488 bytenr = btrfs_node_blockptr(eb, slot);
8489 generation = btrfs_node_ptr_generation(eb, slot);
8490
8491 if (slot == path->slots[wc->level])
8492 goto reada;
8493
8494 if (wc->stage == UPDATE_BACKREF &&
8495 generation <= root->root_key.offset)
8496 continue;
8497
8498 /* We don't lock the tree block, it's OK to be racy here */
8499 ret = btrfs_lookup_extent_info(trans, root, bytenr,
8500 wc->level - 1, 1, &refs,
8501 &flags);
8502 /* We don't care about errors in readahead. */
8503 if (ret < 0)
8504 continue;
8505 BUG_ON(refs == 0);
8506
8507 if (wc->stage == DROP_REFERENCE) {
8508 if (refs == 1)
8509 goto reada;
8510
8511 if (wc->level == 1 &&
8512 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8513 continue;
8514 if (!wc->update_ref ||
8515 generation <= root->root_key.offset)
8516 continue;
8517 btrfs_node_key_to_cpu(eb, &key, slot);
8518 ret = btrfs_comp_cpu_keys(&key,
8519 &wc->update_progress);
8520 if (ret < 0)
8521 continue;
8522 } else {
8523 if (wc->level == 1 &&
8524 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8525 continue;
8526 }
8527 reada:
8528 readahead_tree_block(root, bytenr);
8529 nread++;
8530 }
8531 wc->reada_slot = slot;
8532 }
8533
8534 static int account_leaf_items(struct btrfs_trans_handle *trans,
8535 struct btrfs_root *root,
8536 struct extent_buffer *eb)
8537 {
8538 int nr = btrfs_header_nritems(eb);
8539 int i, extent_type, ret;
8540 struct btrfs_key key;
8541 struct btrfs_file_extent_item *fi;
8542 u64 bytenr, num_bytes;
8543
8544 /* We can be called directly from walk_up_proc() */
8545 if (!root->fs_info->quota_enabled)
8546 return 0;
8547
8548 for (i = 0; i < nr; i++) {
8549 btrfs_item_key_to_cpu(eb, &key, i);
8550
8551 if (key.type != BTRFS_EXTENT_DATA_KEY)
8552 continue;
8553
8554 fi = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
8555 /* filter out non qgroup-accountable extents */
8556 extent_type = btrfs_file_extent_type(eb, fi);
8557
8558 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
8559 continue;
8560
8561 bytenr = btrfs_file_extent_disk_bytenr(eb, fi);
8562 if (!bytenr)
8563 continue;
8564
8565 num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
8566
8567 ret = btrfs_qgroup_insert_dirty_extent(trans, root->fs_info,
8568 bytenr, num_bytes, GFP_NOFS);
8569 if (ret)
8570 return ret;
8571 }
8572 return 0;
8573 }
8574
8575 /*
8576 * Walk up the tree from the bottom, freeing leaves and any interior
8577 * nodes which have had all slots visited. If a node (leaf or
8578 * interior) is freed, the node above it will have it's slot
8579 * incremented. The root node will never be freed.
8580 *
8581 * At the end of this function, we should have a path which has all
8582 * slots incremented to the next position for a search. If we need to
8583 * read a new node it will be NULL and the node above it will have the
8584 * correct slot selected for a later read.
8585 *
8586 * If we increment the root nodes slot counter past the number of
8587 * elements, 1 is returned to signal completion of the search.
8588 */
8589 static int adjust_slots_upwards(struct btrfs_root *root,
8590 struct btrfs_path *path, int root_level)
8591 {
8592 int level = 0;
8593 int nr, slot;
8594 struct extent_buffer *eb;
8595
8596 if (root_level == 0)
8597 return 1;
8598
8599 while (level <= root_level) {
8600 eb = path->nodes[level];
8601 nr = btrfs_header_nritems(eb);
8602 path->slots[level]++;
8603 slot = path->slots[level];
8604 if (slot >= nr || level == 0) {
8605 /*
8606 * Don't free the root - we will detect this
8607 * condition after our loop and return a
8608 * positive value for caller to stop walking the tree.
8609 */
8610 if (level != root_level) {
8611 btrfs_tree_unlock_rw(eb, path->locks[level]);
8612 path->locks[level] = 0;
8613
8614 free_extent_buffer(eb);
8615 path->nodes[level] = NULL;
8616 path->slots[level] = 0;
8617 }
8618 } else {
8619 /*
8620 * We have a valid slot to walk back down
8621 * from. Stop here so caller can process these
8622 * new nodes.
8623 */
8624 break;
8625 }
8626
8627 level++;
8628 }
8629
8630 eb = path->nodes[root_level];
8631 if (path->slots[root_level] >= btrfs_header_nritems(eb))
8632 return 1;
8633
8634 return 0;
8635 }
8636
8637 /*
8638 * root_eb is the subtree root and is locked before this function is called.
8639 */
8640 static int account_shared_subtree(struct btrfs_trans_handle *trans,
8641 struct btrfs_root *root,
8642 struct extent_buffer *root_eb,
8643 u64 root_gen,
8644 int root_level)
8645 {
8646 int ret = 0;
8647 int level;
8648 struct extent_buffer *eb = root_eb;
8649 struct btrfs_path *path = NULL;
8650
8651 BUG_ON(root_level < 0 || root_level > BTRFS_MAX_LEVEL);
8652 BUG_ON(root_eb == NULL);
8653
8654 if (!root->fs_info->quota_enabled)
8655 return 0;
8656
8657 if (!extent_buffer_uptodate(root_eb)) {
8658 ret = btrfs_read_buffer(root_eb, root_gen);
8659 if (ret)
8660 goto out;
8661 }
8662
8663 if (root_level == 0) {
8664 ret = account_leaf_items(trans, root, root_eb);
8665 goto out;
8666 }
8667
8668 path = btrfs_alloc_path();
8669 if (!path)
8670 return -ENOMEM;
8671
8672 /*
8673 * Walk down the tree. Missing extent blocks are filled in as
8674 * we go. Metadata is accounted every time we read a new
8675 * extent block.
8676 *
8677 * When we reach a leaf, we account for file extent items in it,
8678 * walk back up the tree (adjusting slot pointers as we go)
8679 * and restart the search process.
8680 */
8681 extent_buffer_get(root_eb); /* For path */
8682 path->nodes[root_level] = root_eb;
8683 path->slots[root_level] = 0;
8684 path->locks[root_level] = 0; /* so release_path doesn't try to unlock */
8685 walk_down:
8686 level = root_level;
8687 while (level >= 0) {
8688 if (path->nodes[level] == NULL) {
8689 int parent_slot;
8690 u64 child_gen;
8691 u64 child_bytenr;
8692
8693 /* We need to get child blockptr/gen from
8694 * parent before we can read it. */
8695 eb = path->nodes[level + 1];
8696 parent_slot = path->slots[level + 1];
8697 child_bytenr = btrfs_node_blockptr(eb, parent_slot);
8698 child_gen = btrfs_node_ptr_generation(eb, parent_slot);
8699
8700 eb = read_tree_block(root, child_bytenr, child_gen);
8701 if (IS_ERR(eb)) {
8702 ret = PTR_ERR(eb);
8703 goto out;
8704 } else if (!extent_buffer_uptodate(eb)) {
8705 free_extent_buffer(eb);
8706 ret = -EIO;
8707 goto out;
8708 }
8709
8710 path->nodes[level] = eb;
8711 path->slots[level] = 0;
8712
8713 btrfs_tree_read_lock(eb);
8714 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
8715 path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
8716
8717 ret = btrfs_qgroup_insert_dirty_extent(trans,
8718 root->fs_info, child_bytenr,
8719 root->nodesize, GFP_NOFS);
8720 if (ret)
8721 goto out;
8722 }
8723
8724 if (level == 0) {
8725 ret = account_leaf_items(trans, root, path->nodes[level]);
8726 if (ret)
8727 goto out;
8728
8729 /* Nonzero return here means we completed our search */
8730 ret = adjust_slots_upwards(root, path, root_level);
8731 if (ret)
8732 break;
8733
8734 /* Restart search with new slots */
8735 goto walk_down;
8736 }
8737
8738 level--;
8739 }
8740
8741 ret = 0;
8742 out:
8743 btrfs_free_path(path);
8744
8745 return ret;
8746 }
8747
8748 /*
8749 * helper to process tree block while walking down the tree.
8750 *
8751 * when wc->stage == UPDATE_BACKREF, this function updates
8752 * back refs for pointers in the block.
8753 *
8754 * NOTE: return value 1 means we should stop walking down.
8755 */
8756 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
8757 struct btrfs_root *root,
8758 struct btrfs_path *path,
8759 struct walk_control *wc, int lookup_info)
8760 {
8761 int level = wc->level;
8762 struct extent_buffer *eb = path->nodes[level];
8763 u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8764 int ret;
8765
8766 if (wc->stage == UPDATE_BACKREF &&
8767 btrfs_header_owner(eb) != root->root_key.objectid)
8768 return 1;
8769
8770 /*
8771 * when reference count of tree block is 1, it won't increase
8772 * again. once full backref flag is set, we never clear it.
8773 */
8774 if (lookup_info &&
8775 ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
8776 (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
8777 BUG_ON(!path->locks[level]);
8778 ret = btrfs_lookup_extent_info(trans, root,
8779 eb->start, level, 1,
8780 &wc->refs[level],
8781 &wc->flags[level]);
8782 BUG_ON(ret == -ENOMEM);
8783 if (ret)
8784 return ret;
8785 BUG_ON(wc->refs[level] == 0);
8786 }
8787
8788 if (wc->stage == DROP_REFERENCE) {
8789 if (wc->refs[level] > 1)
8790 return 1;
8791
8792 if (path->locks[level] && !wc->keep_locks) {
8793 btrfs_tree_unlock_rw(eb, path->locks[level]);
8794 path->locks[level] = 0;
8795 }
8796 return 0;
8797 }
8798
8799 /* wc->stage == UPDATE_BACKREF */
8800 if (!(wc->flags[level] & flag)) {
8801 BUG_ON(!path->locks[level]);
8802 ret = btrfs_inc_ref(trans, root, eb, 1);
8803 BUG_ON(ret); /* -ENOMEM */
8804 ret = btrfs_dec_ref(trans, root, eb, 0);
8805 BUG_ON(ret); /* -ENOMEM */
8806 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
8807 eb->len, flag,
8808 btrfs_header_level(eb), 0);
8809 BUG_ON(ret); /* -ENOMEM */
8810 wc->flags[level] |= flag;
8811 }
8812
8813 /*
8814 * the block is shared by multiple trees, so it's not good to
8815 * keep the tree lock
8816 */
8817 if (path->locks[level] && level > 0) {
8818 btrfs_tree_unlock_rw(eb, path->locks[level]);
8819 path->locks[level] = 0;
8820 }
8821 return 0;
8822 }
8823
8824 /*
8825 * helper to process tree block pointer.
8826 *
8827 * when wc->stage == DROP_REFERENCE, this function checks
8828 * reference count of the block pointed to. if the block
8829 * is shared and we need update back refs for the subtree
8830 * rooted at the block, this function changes wc->stage to
8831 * UPDATE_BACKREF. if the block is shared and there is no
8832 * need to update back, this function drops the reference
8833 * to the block.
8834 *
8835 * NOTE: return value 1 means we should stop walking down.
8836 */
8837 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
8838 struct btrfs_root *root,
8839 struct btrfs_path *path,
8840 struct walk_control *wc, int *lookup_info)
8841 {
8842 u64 bytenr;
8843 u64 generation;
8844 u64 parent;
8845 u32 blocksize;
8846 struct btrfs_key key;
8847 struct extent_buffer *next;
8848 int level = wc->level;
8849 int reada = 0;
8850 int ret = 0;
8851 bool need_account = false;
8852
8853 generation = btrfs_node_ptr_generation(path->nodes[level],
8854 path->slots[level]);
8855 /*
8856 * if the lower level block was created before the snapshot
8857 * was created, we know there is no need to update back refs
8858 * for the subtree
8859 */
8860 if (wc->stage == UPDATE_BACKREF &&
8861 generation <= root->root_key.offset) {
8862 *lookup_info = 1;
8863 return 1;
8864 }
8865
8866 bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
8867 blocksize = root->nodesize;
8868
8869 next = btrfs_find_tree_block(root->fs_info, bytenr);
8870 if (!next) {
8871 next = btrfs_find_create_tree_block(root, bytenr);
8872 if (IS_ERR(next))
8873 return PTR_ERR(next);
8874
8875 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
8876 level - 1);
8877 reada = 1;
8878 }
8879 btrfs_tree_lock(next);
8880 btrfs_set_lock_blocking(next);
8881
8882 ret = btrfs_lookup_extent_info(trans, root, bytenr, level - 1, 1,
8883 &wc->refs[level - 1],
8884 &wc->flags[level - 1]);
8885 if (ret < 0) {
8886 btrfs_tree_unlock(next);
8887 return ret;
8888 }
8889
8890 if (unlikely(wc->refs[level - 1] == 0)) {
8891 btrfs_err(root->fs_info, "Missing references.");
8892 BUG();
8893 }
8894 *lookup_info = 0;
8895
8896 if (wc->stage == DROP_REFERENCE) {
8897 if (wc->refs[level - 1] > 1) {
8898 need_account = true;
8899 if (level == 1 &&
8900 (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8901 goto skip;
8902
8903 if (!wc->update_ref ||
8904 generation <= root->root_key.offset)
8905 goto skip;
8906
8907 btrfs_node_key_to_cpu(path->nodes[level], &key,
8908 path->slots[level]);
8909 ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
8910 if (ret < 0)
8911 goto skip;
8912
8913 wc->stage = UPDATE_BACKREF;
8914 wc->shared_level = level - 1;
8915 }
8916 } else {
8917 if (level == 1 &&
8918 (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8919 goto skip;
8920 }
8921
8922 if (!btrfs_buffer_uptodate(next, generation, 0)) {
8923 btrfs_tree_unlock(next);
8924 free_extent_buffer(next);
8925 next = NULL;
8926 *lookup_info = 1;
8927 }
8928
8929 if (!next) {
8930 if (reada && level == 1)
8931 reada_walk_down(trans, root, wc, path);
8932 next = read_tree_block(root, bytenr, generation);
8933 if (IS_ERR(next)) {
8934 return PTR_ERR(next);
8935 } else if (!extent_buffer_uptodate(next)) {
8936 free_extent_buffer(next);
8937 return -EIO;
8938 }
8939 btrfs_tree_lock(next);
8940 btrfs_set_lock_blocking(next);
8941 }
8942
8943 level--;
8944 BUG_ON(level != btrfs_header_level(next));
8945 path->nodes[level] = next;
8946 path->slots[level] = 0;
8947 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8948 wc->level = level;
8949 if (wc->level == 1)
8950 wc->reada_slot = 0;
8951 return 0;
8952 skip:
8953 wc->refs[level - 1] = 0;
8954 wc->flags[level - 1] = 0;
8955 if (wc->stage == DROP_REFERENCE) {
8956 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
8957 parent = path->nodes[level]->start;
8958 } else {
8959 BUG_ON(root->root_key.objectid !=
8960 btrfs_header_owner(path->nodes[level]));
8961 parent = 0;
8962 }
8963
8964 if (need_account) {
8965 ret = account_shared_subtree(trans, root, next,
8966 generation, level - 1);
8967 if (ret) {
8968 btrfs_err_rl(root->fs_info,
8969 "Error "
8970 "%d accounting shared subtree. Quota "
8971 "is out of sync, rescan required.",
8972 ret);
8973 }
8974 }
8975 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
8976 root->root_key.objectid, level - 1, 0);
8977 BUG_ON(ret); /* -ENOMEM */
8978 }
8979 btrfs_tree_unlock(next);
8980 free_extent_buffer(next);
8981 *lookup_info = 1;
8982 return 1;
8983 }
8984
8985 /*
8986 * helper to process tree block while walking up the tree.
8987 *
8988 * when wc->stage == DROP_REFERENCE, this function drops
8989 * reference count on the block.
8990 *
8991 * when wc->stage == UPDATE_BACKREF, this function changes
8992 * wc->stage back to DROP_REFERENCE if we changed wc->stage
8993 * to UPDATE_BACKREF previously while processing the block.
8994 *
8995 * NOTE: return value 1 means we should stop walking up.
8996 */
8997 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
8998 struct btrfs_root *root,
8999 struct btrfs_path *path,
9000 struct walk_control *wc)
9001 {
9002 int ret;
9003 int level = wc->level;
9004 struct extent_buffer *eb = path->nodes[level];
9005 u64 parent = 0;
9006
9007 if (wc->stage == UPDATE_BACKREF) {
9008 BUG_ON(wc->shared_level < level);
9009 if (level < wc->shared_level)
9010 goto out;
9011
9012 ret = find_next_key(path, level + 1, &wc->update_progress);
9013 if (ret > 0)
9014 wc->update_ref = 0;
9015
9016 wc->stage = DROP_REFERENCE;
9017 wc->shared_level = -1;
9018 path->slots[level] = 0;
9019
9020 /*
9021 * check reference count again if the block isn't locked.
9022 * we should start walking down the tree again if reference
9023 * count is one.
9024 */
9025 if (!path->locks[level]) {
9026 BUG_ON(level == 0);
9027 btrfs_tree_lock(eb);
9028 btrfs_set_lock_blocking(eb);
9029 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9030
9031 ret = btrfs_lookup_extent_info(trans, root,
9032 eb->start, level, 1,
9033 &wc->refs[level],
9034 &wc->flags[level]);
9035 if (ret < 0) {
9036 btrfs_tree_unlock_rw(eb, path->locks[level]);
9037 path->locks[level] = 0;
9038 return ret;
9039 }
9040 BUG_ON(wc->refs[level] == 0);
9041 if (wc->refs[level] == 1) {
9042 btrfs_tree_unlock_rw(eb, path->locks[level]);
9043 path->locks[level] = 0;
9044 return 1;
9045 }
9046 }
9047 }
9048
9049 /* wc->stage == DROP_REFERENCE */
9050 BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
9051
9052 if (wc->refs[level] == 1) {
9053 if (level == 0) {
9054 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
9055 ret = btrfs_dec_ref(trans, root, eb, 1);
9056 else
9057 ret = btrfs_dec_ref(trans, root, eb, 0);
9058 BUG_ON(ret); /* -ENOMEM */
9059 ret = account_leaf_items(trans, root, eb);
9060 if (ret) {
9061 btrfs_err_rl(root->fs_info,
9062 "error "
9063 "%d accounting leaf items. Quota "
9064 "is out of sync, rescan required.",
9065 ret);
9066 }
9067 }
9068 /* make block locked assertion in clean_tree_block happy */
9069 if (!path->locks[level] &&
9070 btrfs_header_generation(eb) == trans->transid) {
9071 btrfs_tree_lock(eb);
9072 btrfs_set_lock_blocking(eb);
9073 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9074 }
9075 clean_tree_block(trans, root->fs_info, eb);
9076 }
9077
9078 if (eb == root->node) {
9079 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
9080 parent = eb->start;
9081 else
9082 BUG_ON(root->root_key.objectid !=
9083 btrfs_header_owner(eb));
9084 } else {
9085 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
9086 parent = path->nodes[level + 1]->start;
9087 else
9088 BUG_ON(root->root_key.objectid !=
9089 btrfs_header_owner(path->nodes[level + 1]));
9090 }
9091
9092 btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
9093 out:
9094 wc->refs[level] = 0;
9095 wc->flags[level] = 0;
9096 return 0;
9097 }
9098
9099 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
9100 struct btrfs_root *root,
9101 struct btrfs_path *path,
9102 struct walk_control *wc)
9103 {
9104 int level = wc->level;
9105 int lookup_info = 1;
9106 int ret;
9107
9108 while (level >= 0) {
9109 ret = walk_down_proc(trans, root, path, wc, lookup_info);
9110 if (ret > 0)
9111 break;
9112
9113 if (level == 0)
9114 break;
9115
9116 if (path->slots[level] >=
9117 btrfs_header_nritems(path->nodes[level]))
9118 break;
9119
9120 ret = do_walk_down(trans, root, path, wc, &lookup_info);
9121 if (ret > 0) {
9122 path->slots[level]++;
9123 continue;
9124 } else if (ret < 0)
9125 return ret;
9126 level = wc->level;
9127 }
9128 return 0;
9129 }
9130
9131 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
9132 struct btrfs_root *root,
9133 struct btrfs_path *path,
9134 struct walk_control *wc, int max_level)
9135 {
9136 int level = wc->level;
9137 int ret;
9138
9139 path->slots[level] = btrfs_header_nritems(path->nodes[level]);
9140 while (level < max_level && path->nodes[level]) {
9141 wc->level = level;
9142 if (path->slots[level] + 1 <
9143 btrfs_header_nritems(path->nodes[level])) {
9144 path->slots[level]++;
9145 return 0;
9146 } else {
9147 ret = walk_up_proc(trans, root, path, wc);
9148 if (ret > 0)
9149 return 0;
9150
9151 if (path->locks[level]) {
9152 btrfs_tree_unlock_rw(path->nodes[level],
9153 path->locks[level]);
9154 path->locks[level] = 0;
9155 }
9156 free_extent_buffer(path->nodes[level]);
9157 path->nodes[level] = NULL;
9158 level++;
9159 }
9160 }
9161 return 1;
9162 }
9163
9164 /*
9165 * drop a subvolume tree.
9166 *
9167 * this function traverses the tree freeing any blocks that only
9168 * referenced by the tree.
9169 *
9170 * when a shared tree block is found. this function decreases its
9171 * reference count by one. if update_ref is true, this function
9172 * also make sure backrefs for the shared block and all lower level
9173 * blocks are properly updated.
9174 *
9175 * If called with for_reloc == 0, may exit early with -EAGAIN
9176 */
9177 int btrfs_drop_snapshot(struct btrfs_root *root,
9178 struct btrfs_block_rsv *block_rsv, int update_ref,
9179 int for_reloc)
9180 {
9181 struct btrfs_path *path;
9182 struct btrfs_trans_handle *trans;
9183 struct btrfs_root *tree_root = root->fs_info->tree_root;
9184 struct btrfs_root_item *root_item = &root->root_item;
9185 struct walk_control *wc;
9186 struct btrfs_key key;
9187 int err = 0;
9188 int ret;
9189 int level;
9190 bool root_dropped = false;
9191
9192 btrfs_debug(root->fs_info, "Drop subvolume %llu", root->objectid);
9193
9194 path = btrfs_alloc_path();
9195 if (!path) {
9196 err = -ENOMEM;
9197 goto out;
9198 }
9199
9200 wc = kzalloc(sizeof(*wc), GFP_NOFS);
9201 if (!wc) {
9202 btrfs_free_path(path);
9203 err = -ENOMEM;
9204 goto out;
9205 }
9206
9207 trans = btrfs_start_transaction(tree_root, 0);
9208 if (IS_ERR(trans)) {
9209 err = PTR_ERR(trans);
9210 goto out_free;
9211 }
9212
9213 if (block_rsv)
9214 trans->block_rsv = block_rsv;
9215
9216 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
9217 level = btrfs_header_level(root->node);
9218 path->nodes[level] = btrfs_lock_root_node(root);
9219 btrfs_set_lock_blocking(path->nodes[level]);
9220 path->slots[level] = 0;
9221 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9222 memset(&wc->update_progress, 0,
9223 sizeof(wc->update_progress));
9224 } else {
9225 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
9226 memcpy(&wc->update_progress, &key,
9227 sizeof(wc->update_progress));
9228
9229 level = root_item->drop_level;
9230 BUG_ON(level == 0);
9231 path->lowest_level = level;
9232 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
9233 path->lowest_level = 0;
9234 if (ret < 0) {
9235 err = ret;
9236 goto out_end_trans;
9237 }
9238 WARN_ON(ret > 0);
9239
9240 /*
9241 * unlock our path, this is safe because only this
9242 * function is allowed to delete this snapshot
9243 */
9244 btrfs_unlock_up_safe(path, 0);
9245
9246 level = btrfs_header_level(root->node);
9247 while (1) {
9248 btrfs_tree_lock(path->nodes[level]);
9249 btrfs_set_lock_blocking(path->nodes[level]);
9250 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9251
9252 ret = btrfs_lookup_extent_info(trans, root,
9253 path->nodes[level]->start,
9254 level, 1, &wc->refs[level],
9255 &wc->flags[level]);
9256 if (ret < 0) {
9257 err = ret;
9258 goto out_end_trans;
9259 }
9260 BUG_ON(wc->refs[level] == 0);
9261
9262 if (level == root_item->drop_level)
9263 break;
9264
9265 btrfs_tree_unlock(path->nodes[level]);
9266 path->locks[level] = 0;
9267 WARN_ON(wc->refs[level] != 1);
9268 level--;
9269 }
9270 }
9271
9272 wc->level = level;
9273 wc->shared_level = -1;
9274 wc->stage = DROP_REFERENCE;
9275 wc->update_ref = update_ref;
9276 wc->keep_locks = 0;
9277 wc->for_reloc = for_reloc;
9278 wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
9279
9280 while (1) {
9281
9282 ret = walk_down_tree(trans, root, path, wc);
9283 if (ret < 0) {
9284 err = ret;
9285 break;
9286 }
9287
9288 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
9289 if (ret < 0) {
9290 err = ret;
9291 break;
9292 }
9293
9294 if (ret > 0) {
9295 BUG_ON(wc->stage != DROP_REFERENCE);
9296 break;
9297 }
9298
9299 if (wc->stage == DROP_REFERENCE) {
9300 level = wc->level;
9301 btrfs_node_key(path->nodes[level],
9302 &root_item->drop_progress,
9303 path->slots[level]);
9304 root_item->drop_level = level;
9305 }
9306
9307 BUG_ON(wc->level == 0);
9308 if (btrfs_should_end_transaction(trans, tree_root) ||
9309 (!for_reloc && btrfs_need_cleaner_sleep(root))) {
9310 ret = btrfs_update_root(trans, tree_root,
9311 &root->root_key,
9312 root_item);
9313 if (ret) {
9314 btrfs_abort_transaction(trans, ret);
9315 err = ret;
9316 goto out_end_trans;
9317 }
9318
9319 btrfs_end_transaction_throttle(trans, tree_root);
9320 if (!for_reloc && btrfs_need_cleaner_sleep(root)) {
9321 pr_debug("BTRFS: drop snapshot early exit\n");
9322 err = -EAGAIN;
9323 goto out_free;
9324 }
9325
9326 trans = btrfs_start_transaction(tree_root, 0);
9327 if (IS_ERR(trans)) {
9328 err = PTR_ERR(trans);
9329 goto out_free;
9330 }
9331 if (block_rsv)
9332 trans->block_rsv = block_rsv;
9333 }
9334 }
9335 btrfs_release_path(path);
9336 if (err)
9337 goto out_end_trans;
9338
9339 ret = btrfs_del_root(trans, tree_root, &root->root_key);
9340 if (ret) {
9341 btrfs_abort_transaction(trans, ret);
9342 goto out_end_trans;
9343 }
9344
9345 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
9346 ret = btrfs_find_root(tree_root, &root->root_key, path,
9347 NULL, NULL);
9348 if (ret < 0) {
9349 btrfs_abort_transaction(trans, ret);
9350 err = ret;
9351 goto out_end_trans;
9352 } else if (ret > 0) {
9353 /* if we fail to delete the orphan item this time
9354 * around, it'll get picked up the next time.
9355 *
9356 * The most common failure here is just -ENOENT.
9357 */
9358 btrfs_del_orphan_item(trans, tree_root,
9359 root->root_key.objectid);
9360 }
9361 }
9362
9363 if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
9364 btrfs_add_dropped_root(trans, root);
9365 } else {
9366 free_extent_buffer(root->node);
9367 free_extent_buffer(root->commit_root);
9368 btrfs_put_fs_root(root);
9369 }
9370 root_dropped = true;
9371 out_end_trans:
9372 btrfs_end_transaction_throttle(trans, tree_root);
9373 out_free:
9374 kfree(wc);
9375 btrfs_free_path(path);
9376 out:
9377 /*
9378 * So if we need to stop dropping the snapshot for whatever reason we
9379 * need to make sure to add it back to the dead root list so that we
9380 * keep trying to do the work later. This also cleans up roots if we
9381 * don't have it in the radix (like when we recover after a power fail
9382 * or unmount) so we don't leak memory.
9383 */
9384 if (!for_reloc && root_dropped == false)
9385 btrfs_add_dead_root(root);
9386 if (err && err != -EAGAIN)
9387 btrfs_handle_fs_error(root->fs_info, err, NULL);
9388 return err;
9389 }
9390
9391 /*
9392 * drop subtree rooted at tree block 'node'.
9393 *
9394 * NOTE: this function will unlock and release tree block 'node'
9395 * only used by relocation code
9396 */
9397 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
9398 struct btrfs_root *root,
9399 struct extent_buffer *node,
9400 struct extent_buffer *parent)
9401 {
9402 struct btrfs_path *path;
9403 struct walk_control *wc;
9404 int level;
9405 int parent_level;
9406 int ret = 0;
9407 int wret;
9408
9409 BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
9410
9411 path = btrfs_alloc_path();
9412 if (!path)
9413 return -ENOMEM;
9414
9415 wc = kzalloc(sizeof(*wc), GFP_NOFS);
9416 if (!wc) {
9417 btrfs_free_path(path);
9418 return -ENOMEM;
9419 }
9420
9421 btrfs_assert_tree_locked(parent);
9422 parent_level = btrfs_header_level(parent);
9423 extent_buffer_get(parent);
9424 path->nodes[parent_level] = parent;
9425 path->slots[parent_level] = btrfs_header_nritems(parent);
9426
9427 btrfs_assert_tree_locked(node);
9428 level = btrfs_header_level(node);
9429 path->nodes[level] = node;
9430 path->slots[level] = 0;
9431 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9432
9433 wc->refs[parent_level] = 1;
9434 wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
9435 wc->level = level;
9436 wc->shared_level = -1;
9437 wc->stage = DROP_REFERENCE;
9438 wc->update_ref = 0;
9439 wc->keep_locks = 1;
9440 wc->for_reloc = 1;
9441 wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
9442
9443 while (1) {
9444 wret = walk_down_tree(trans, root, path, wc);
9445 if (wret < 0) {
9446 ret = wret;
9447 break;
9448 }
9449
9450 wret = walk_up_tree(trans, root, path, wc, parent_level);
9451 if (wret < 0)
9452 ret = wret;
9453 if (wret != 0)
9454 break;
9455 }
9456
9457 kfree(wc);
9458 btrfs_free_path(path);
9459 return ret;
9460 }
9461
9462 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
9463 {
9464 u64 num_devices;
9465 u64 stripped;
9466
9467 /*
9468 * if restripe for this chunk_type is on pick target profile and
9469 * return, otherwise do the usual balance
9470 */
9471 stripped = get_restripe_target(root->fs_info, flags);
9472 if (stripped)
9473 return extended_to_chunk(stripped);
9474
9475 num_devices = root->fs_info->fs_devices->rw_devices;
9476
9477 stripped = BTRFS_BLOCK_GROUP_RAID0 |
9478 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
9479 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
9480
9481 if (num_devices == 1) {
9482 stripped |= BTRFS_BLOCK_GROUP_DUP;
9483 stripped = flags & ~stripped;
9484
9485 /* turn raid0 into single device chunks */
9486 if (flags & BTRFS_BLOCK_GROUP_RAID0)
9487 return stripped;
9488
9489 /* turn mirroring into duplication */
9490 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
9491 BTRFS_BLOCK_GROUP_RAID10))
9492 return stripped | BTRFS_BLOCK_GROUP_DUP;
9493 } else {
9494 /* they already had raid on here, just return */
9495 if (flags & stripped)
9496 return flags;
9497
9498 stripped |= BTRFS_BLOCK_GROUP_DUP;
9499 stripped = flags & ~stripped;
9500
9501 /* switch duplicated blocks with raid1 */
9502 if (flags & BTRFS_BLOCK_GROUP_DUP)
9503 return stripped | BTRFS_BLOCK_GROUP_RAID1;
9504
9505 /* this is drive concat, leave it alone */
9506 }
9507
9508 return flags;
9509 }
9510
9511 static int inc_block_group_ro(struct btrfs_block_group_cache *cache, int force)
9512 {
9513 struct btrfs_space_info *sinfo = cache->space_info;
9514 u64 num_bytes;
9515 u64 min_allocable_bytes;
9516 int ret = -ENOSPC;
9517
9518 /*
9519 * We need some metadata space and system metadata space for
9520 * allocating chunks in some corner cases until we force to set
9521 * it to be readonly.
9522 */
9523 if ((sinfo->flags &
9524 (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
9525 !force)
9526 min_allocable_bytes = SZ_1M;
9527 else
9528 min_allocable_bytes = 0;
9529
9530 spin_lock(&sinfo->lock);
9531 spin_lock(&cache->lock);
9532
9533 if (cache->ro) {
9534 cache->ro++;
9535 ret = 0;
9536 goto out;
9537 }
9538
9539 num_bytes = cache->key.offset - cache->reserved - cache->pinned -
9540 cache->bytes_super - btrfs_block_group_used(&cache->item);
9541
9542 if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
9543 sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
9544 min_allocable_bytes <= sinfo->total_bytes) {
9545 sinfo->bytes_readonly += num_bytes;
9546 cache->ro++;
9547 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
9548 ret = 0;
9549 }
9550 out:
9551 spin_unlock(&cache->lock);
9552 spin_unlock(&sinfo->lock);
9553 return ret;
9554 }
9555
9556 int btrfs_inc_block_group_ro(struct btrfs_root *root,
9557 struct btrfs_block_group_cache *cache)
9558
9559 {
9560 struct btrfs_trans_handle *trans;
9561 u64 alloc_flags;
9562 int ret;
9563
9564 again:
9565 trans = btrfs_join_transaction(root);
9566 if (IS_ERR(trans))
9567 return PTR_ERR(trans);
9568
9569 /*
9570 * we're not allowed to set block groups readonly after the dirty
9571 * block groups cache has started writing. If it already started,
9572 * back off and let this transaction commit
9573 */
9574 mutex_lock(&root->fs_info->ro_block_group_mutex);
9575 if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
9576 u64 transid = trans->transid;
9577
9578 mutex_unlock(&root->fs_info->ro_block_group_mutex);
9579 btrfs_end_transaction(trans, root);
9580
9581 ret = btrfs_wait_for_commit(root, transid);
9582 if (ret)
9583 return ret;
9584 goto again;
9585 }
9586
9587 /*
9588 * if we are changing raid levels, try to allocate a corresponding
9589 * block group with the new raid level.
9590 */
9591 alloc_flags = update_block_group_flags(root, cache->flags);
9592 if (alloc_flags != cache->flags) {
9593 ret = do_chunk_alloc(trans, root, alloc_flags,
9594 CHUNK_ALLOC_FORCE);
9595 /*
9596 * ENOSPC is allowed here, we may have enough space
9597 * already allocated at the new raid level to
9598 * carry on
9599 */
9600 if (ret == -ENOSPC)
9601 ret = 0;
9602 if (ret < 0)
9603 goto out;
9604 }
9605
9606 ret = inc_block_group_ro(cache, 0);
9607 if (!ret)
9608 goto out;
9609 alloc_flags = get_alloc_profile(root, cache->space_info->flags);
9610 ret = do_chunk_alloc(trans, root, alloc_flags,
9611 CHUNK_ALLOC_FORCE);
9612 if (ret < 0)
9613 goto out;
9614 ret = inc_block_group_ro(cache, 0);
9615 out:
9616 if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
9617 alloc_flags = update_block_group_flags(root, cache->flags);
9618 lock_chunks(root->fs_info->chunk_root);
9619 check_system_chunk(trans, root, alloc_flags);
9620 unlock_chunks(root->fs_info->chunk_root);
9621 }
9622 mutex_unlock(&root->fs_info->ro_block_group_mutex);
9623
9624 btrfs_end_transaction(trans, root);
9625 return ret;
9626 }
9627
9628 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
9629 struct btrfs_root *root, u64 type)
9630 {
9631 u64 alloc_flags = get_alloc_profile(root, type);
9632 return do_chunk_alloc(trans, root, alloc_flags,
9633 CHUNK_ALLOC_FORCE);
9634 }
9635
9636 /*
9637 * helper to account the unused space of all the readonly block group in the
9638 * space_info. takes mirrors into account.
9639 */
9640 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
9641 {
9642 struct btrfs_block_group_cache *block_group;
9643 u64 free_bytes = 0;
9644 int factor;
9645
9646 /* It's df, we don't care if it's racy */
9647 if (list_empty(&sinfo->ro_bgs))
9648 return 0;
9649
9650 spin_lock(&sinfo->lock);
9651 list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
9652 spin_lock(&block_group->lock);
9653
9654 if (!block_group->ro) {
9655 spin_unlock(&block_group->lock);
9656 continue;
9657 }
9658
9659 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
9660 BTRFS_BLOCK_GROUP_RAID10 |
9661 BTRFS_BLOCK_GROUP_DUP))
9662 factor = 2;
9663 else
9664 factor = 1;
9665
9666 free_bytes += (block_group->key.offset -
9667 btrfs_block_group_used(&block_group->item)) *
9668 factor;
9669
9670 spin_unlock(&block_group->lock);
9671 }
9672 spin_unlock(&sinfo->lock);
9673
9674 return free_bytes;
9675 }
9676
9677 void btrfs_dec_block_group_ro(struct btrfs_root *root,
9678 struct btrfs_block_group_cache *cache)
9679 {
9680 struct btrfs_space_info *sinfo = cache->space_info;
9681 u64 num_bytes;
9682
9683 BUG_ON(!cache->ro);
9684
9685 spin_lock(&sinfo->lock);
9686 spin_lock(&cache->lock);
9687 if (!--cache->ro) {
9688 num_bytes = cache->key.offset - cache->reserved -
9689 cache->pinned - cache->bytes_super -
9690 btrfs_block_group_used(&cache->item);
9691 sinfo->bytes_readonly -= num_bytes;
9692 list_del_init(&cache->ro_list);
9693 }
9694 spin_unlock(&cache->lock);
9695 spin_unlock(&sinfo->lock);
9696 }
9697
9698 /*
9699 * checks to see if its even possible to relocate this block group.
9700 *
9701 * @return - -1 if it's not a good idea to relocate this block group, 0 if its
9702 * ok to go ahead and try.
9703 */
9704 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
9705 {
9706 struct btrfs_block_group_cache *block_group;
9707 struct btrfs_space_info *space_info;
9708 struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
9709 struct btrfs_device *device;
9710 struct btrfs_trans_handle *trans;
9711 u64 min_free;
9712 u64 dev_min = 1;
9713 u64 dev_nr = 0;
9714 u64 target;
9715 int debug;
9716 int index;
9717 int full = 0;
9718 int ret = 0;
9719
9720 debug = btrfs_test_opt(root->fs_info, ENOSPC_DEBUG);
9721
9722 block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
9723
9724 /* odd, couldn't find the block group, leave it alone */
9725 if (!block_group) {
9726 if (debug)
9727 btrfs_warn(root->fs_info,
9728 "can't find block group for bytenr %llu",
9729 bytenr);
9730 return -1;
9731 }
9732
9733 min_free = btrfs_block_group_used(&block_group->item);
9734
9735 /* no bytes used, we're good */
9736 if (!min_free)
9737 goto out;
9738
9739 space_info = block_group->space_info;
9740 spin_lock(&space_info->lock);
9741
9742 full = space_info->full;
9743
9744 /*
9745 * if this is the last block group we have in this space, we can't
9746 * relocate it unless we're able to allocate a new chunk below.
9747 *
9748 * Otherwise, we need to make sure we have room in the space to handle
9749 * all of the extents from this block group. If we can, we're good
9750 */
9751 if ((space_info->total_bytes != block_group->key.offset) &&
9752 (space_info->bytes_used + space_info->bytes_reserved +
9753 space_info->bytes_pinned + space_info->bytes_readonly +
9754 min_free < space_info->total_bytes)) {
9755 spin_unlock(&space_info->lock);
9756 goto out;
9757 }
9758 spin_unlock(&space_info->lock);
9759
9760 /*
9761 * ok we don't have enough space, but maybe we have free space on our
9762 * devices to allocate new chunks for relocation, so loop through our
9763 * alloc devices and guess if we have enough space. if this block
9764 * group is going to be restriped, run checks against the target
9765 * profile instead of the current one.
9766 */
9767 ret = -1;
9768
9769 /*
9770 * index:
9771 * 0: raid10
9772 * 1: raid1
9773 * 2: dup
9774 * 3: raid0
9775 * 4: single
9776 */
9777 target = get_restripe_target(root->fs_info, block_group->flags);
9778 if (target) {
9779 index = __get_raid_index(extended_to_chunk(target));
9780 } else {
9781 /*
9782 * this is just a balance, so if we were marked as full
9783 * we know there is no space for a new chunk
9784 */
9785 if (full) {
9786 if (debug)
9787 btrfs_warn(root->fs_info,
9788 "no space to alloc new chunk for block group %llu",
9789 block_group->key.objectid);
9790 goto out;
9791 }
9792
9793 index = get_block_group_index(block_group);
9794 }
9795
9796 if (index == BTRFS_RAID_RAID10) {
9797 dev_min = 4;
9798 /* Divide by 2 */
9799 min_free >>= 1;
9800 } else if (index == BTRFS_RAID_RAID1) {
9801 dev_min = 2;
9802 } else if (index == BTRFS_RAID_DUP) {
9803 /* Multiply by 2 */
9804 min_free <<= 1;
9805 } else if (index == BTRFS_RAID_RAID0) {
9806 dev_min = fs_devices->rw_devices;
9807 min_free = div64_u64(min_free, dev_min);
9808 }
9809
9810 /* We need to do this so that we can look at pending chunks */
9811 trans = btrfs_join_transaction(root);
9812 if (IS_ERR(trans)) {
9813 ret = PTR_ERR(trans);
9814 goto out;
9815 }
9816
9817 mutex_lock(&root->fs_info->chunk_mutex);
9818 list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
9819 u64 dev_offset;
9820
9821 /*
9822 * check to make sure we can actually find a chunk with enough
9823 * space to fit our block group in.
9824 */
9825 if (device->total_bytes > device->bytes_used + min_free &&
9826 !device->is_tgtdev_for_dev_replace) {
9827 ret = find_free_dev_extent(trans, device, min_free,
9828 &dev_offset, NULL);
9829 if (!ret)
9830 dev_nr++;
9831
9832 if (dev_nr >= dev_min)
9833 break;
9834
9835 ret = -1;
9836 }
9837 }
9838 if (debug && ret == -1)
9839 btrfs_warn(root->fs_info,
9840 "no space to allocate a new chunk for block group %llu",
9841 block_group->key.objectid);
9842 mutex_unlock(&root->fs_info->chunk_mutex);
9843 btrfs_end_transaction(trans, root);
9844 out:
9845 btrfs_put_block_group(block_group);
9846 return ret;
9847 }
9848
9849 static int find_first_block_group(struct btrfs_root *root,
9850 struct btrfs_path *path, struct btrfs_key *key)
9851 {
9852 int ret = 0;
9853 struct btrfs_key found_key;
9854 struct extent_buffer *leaf;
9855 int slot;
9856
9857 ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
9858 if (ret < 0)
9859 goto out;
9860
9861 while (1) {
9862 slot = path->slots[0];
9863 leaf = path->nodes[0];
9864 if (slot >= btrfs_header_nritems(leaf)) {
9865 ret = btrfs_next_leaf(root, path);
9866 if (ret == 0)
9867 continue;
9868 if (ret < 0)
9869 goto out;
9870 break;
9871 }
9872 btrfs_item_key_to_cpu(leaf, &found_key, slot);
9873
9874 if (found_key.objectid >= key->objectid &&
9875 found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
9876 struct extent_map_tree *em_tree;
9877 struct extent_map *em;
9878
9879 em_tree = &root->fs_info->mapping_tree.map_tree;
9880 read_lock(&em_tree->lock);
9881 em = lookup_extent_mapping(em_tree, found_key.objectid,
9882 found_key.offset);
9883 read_unlock(&em_tree->lock);
9884 if (!em) {
9885 btrfs_err(root->fs_info,
9886 "logical %llu len %llu found bg but no related chunk",
9887 found_key.objectid, found_key.offset);
9888 ret = -ENOENT;
9889 } else {
9890 ret = 0;
9891 }
9892 free_extent_map(em);
9893 goto out;
9894 }
9895 path->slots[0]++;
9896 }
9897 out:
9898 return ret;
9899 }
9900
9901 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
9902 {
9903 struct btrfs_block_group_cache *block_group;
9904 u64 last = 0;
9905
9906 while (1) {
9907 struct inode *inode;
9908
9909 block_group = btrfs_lookup_first_block_group(info, last);
9910 while (block_group) {
9911 spin_lock(&block_group->lock);
9912 if (block_group->iref)
9913 break;
9914 spin_unlock(&block_group->lock);
9915 block_group = next_block_group(info->tree_root,
9916 block_group);
9917 }
9918 if (!block_group) {
9919 if (last == 0)
9920 break;
9921 last = 0;
9922 continue;
9923 }
9924
9925 inode = block_group->inode;
9926 block_group->iref = 0;
9927 block_group->inode = NULL;
9928 spin_unlock(&block_group->lock);
9929 ASSERT(block_group->io_ctl.inode == NULL);
9930 iput(inode);
9931 last = block_group->key.objectid + block_group->key.offset;
9932 btrfs_put_block_group(block_group);
9933 }
9934 }
9935
9936 int btrfs_free_block_groups(struct btrfs_fs_info *info)
9937 {
9938 struct btrfs_block_group_cache *block_group;
9939 struct btrfs_space_info *space_info;
9940 struct btrfs_caching_control *caching_ctl;
9941 struct rb_node *n;
9942
9943 down_write(&info->commit_root_sem);
9944 while (!list_empty(&info->caching_block_groups)) {
9945 caching_ctl = list_entry(info->caching_block_groups.next,
9946 struct btrfs_caching_control, list);
9947 list_del(&caching_ctl->list);
9948 put_caching_control(caching_ctl);
9949 }
9950 up_write(&info->commit_root_sem);
9951
9952 spin_lock(&info->unused_bgs_lock);
9953 while (!list_empty(&info->unused_bgs)) {
9954 block_group = list_first_entry(&info->unused_bgs,
9955 struct btrfs_block_group_cache,
9956 bg_list);
9957 list_del_init(&block_group->bg_list);
9958 btrfs_put_block_group(block_group);
9959 }
9960 spin_unlock(&info->unused_bgs_lock);
9961
9962 spin_lock(&info->block_group_cache_lock);
9963 while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
9964 block_group = rb_entry(n, struct btrfs_block_group_cache,
9965 cache_node);
9966 rb_erase(&block_group->cache_node,
9967 &info->block_group_cache_tree);
9968 RB_CLEAR_NODE(&block_group->cache_node);
9969 spin_unlock(&info->block_group_cache_lock);
9970
9971 down_write(&block_group->space_info->groups_sem);
9972 list_del(&block_group->list);
9973 up_write(&block_group->space_info->groups_sem);
9974
9975 if (block_group->cached == BTRFS_CACHE_STARTED)
9976 wait_block_group_cache_done(block_group);
9977
9978 /*
9979 * We haven't cached this block group, which means we could
9980 * possibly have excluded extents on this block group.
9981 */
9982 if (block_group->cached == BTRFS_CACHE_NO ||
9983 block_group->cached == BTRFS_CACHE_ERROR)
9984 free_excluded_extents(info->extent_root, block_group);
9985
9986 btrfs_remove_free_space_cache(block_group);
9987 ASSERT(list_empty(&block_group->dirty_list));
9988 ASSERT(list_empty(&block_group->io_list));
9989 ASSERT(list_empty(&block_group->bg_list));
9990 ASSERT(atomic_read(&block_group->count) == 1);
9991 btrfs_put_block_group(block_group);
9992
9993 spin_lock(&info->block_group_cache_lock);
9994 }
9995 spin_unlock(&info->block_group_cache_lock);
9996
9997 /* now that all the block groups are freed, go through and
9998 * free all the space_info structs. This is only called during
9999 * the final stages of unmount, and so we know nobody is
10000 * using them. We call synchronize_rcu() once before we start,
10001 * just to be on the safe side.
10002 */
10003 synchronize_rcu();
10004
10005 release_global_block_rsv(info);
10006
10007 while (!list_empty(&info->space_info)) {
10008 int i;
10009
10010 space_info = list_entry(info->space_info.next,
10011 struct btrfs_space_info,
10012 list);
10013
10014 /*
10015 * Do not hide this behind enospc_debug, this is actually
10016 * important and indicates a real bug if this happens.
10017 */
10018 if (WARN_ON(space_info->bytes_pinned > 0 ||
10019 space_info->bytes_reserved > 0 ||
10020 space_info->bytes_may_use > 0))
10021 dump_space_info(space_info, 0, 0);
10022 list_del(&space_info->list);
10023 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
10024 struct kobject *kobj;
10025 kobj = space_info->block_group_kobjs[i];
10026 space_info->block_group_kobjs[i] = NULL;
10027 if (kobj) {
10028 kobject_del(kobj);
10029 kobject_put(kobj);
10030 }
10031 }
10032 kobject_del(&space_info->kobj);
10033 kobject_put(&space_info->kobj);
10034 }
10035 return 0;
10036 }
10037
10038 static void __link_block_group(struct btrfs_space_info *space_info,
10039 struct btrfs_block_group_cache *cache)
10040 {
10041 int index = get_block_group_index(cache);
10042 bool first = false;
10043
10044 down_write(&space_info->groups_sem);
10045 if (list_empty(&space_info->block_groups[index]))
10046 first = true;
10047 list_add_tail(&cache->list, &space_info->block_groups[index]);
10048 up_write(&space_info->groups_sem);
10049
10050 if (first) {
10051 struct raid_kobject *rkobj;
10052 int ret;
10053
10054 rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
10055 if (!rkobj)
10056 goto out_err;
10057 rkobj->raid_type = index;
10058 kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
10059 ret = kobject_add(&rkobj->kobj, &space_info->kobj,
10060 "%s", get_raid_name(index));
10061 if (ret) {
10062 kobject_put(&rkobj->kobj);
10063 goto out_err;
10064 }
10065 space_info->block_group_kobjs[index] = &rkobj->kobj;
10066 }
10067
10068 return;
10069 out_err:
10070 pr_warn("BTRFS: failed to add kobject for block cache. ignoring.\n");
10071 }
10072
10073 static struct btrfs_block_group_cache *
10074 btrfs_create_block_group_cache(struct btrfs_root *root, u64 start, u64 size)
10075 {
10076 struct btrfs_block_group_cache *cache;
10077
10078 cache = kzalloc(sizeof(*cache), GFP_NOFS);
10079 if (!cache)
10080 return NULL;
10081
10082 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
10083 GFP_NOFS);
10084 if (!cache->free_space_ctl) {
10085 kfree(cache);
10086 return NULL;
10087 }
10088
10089 cache->key.objectid = start;
10090 cache->key.offset = size;
10091 cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
10092
10093 cache->sectorsize = root->sectorsize;
10094 cache->fs_info = root->fs_info;
10095 cache->full_stripe_len = btrfs_full_stripe_len(root,
10096 &root->fs_info->mapping_tree,
10097 start);
10098 set_free_space_tree_thresholds(cache);
10099
10100 atomic_set(&cache->count, 1);
10101 spin_lock_init(&cache->lock);
10102 init_rwsem(&cache->data_rwsem);
10103 INIT_LIST_HEAD(&cache->list);
10104 INIT_LIST_HEAD(&cache->cluster_list);
10105 INIT_LIST_HEAD(&cache->bg_list);
10106 INIT_LIST_HEAD(&cache->ro_list);
10107 INIT_LIST_HEAD(&cache->dirty_list);
10108 INIT_LIST_HEAD(&cache->io_list);
10109 btrfs_init_free_space_ctl(cache);
10110 atomic_set(&cache->trimming, 0);
10111 mutex_init(&cache->free_space_lock);
10112
10113 return cache;
10114 }
10115
10116 int btrfs_read_block_groups(struct btrfs_root *root)
10117 {
10118 struct btrfs_path *path;
10119 int ret;
10120 struct btrfs_block_group_cache *cache;
10121 struct btrfs_fs_info *info = root->fs_info;
10122 struct btrfs_space_info *space_info;
10123 struct btrfs_key key;
10124 struct btrfs_key found_key;
10125 struct extent_buffer *leaf;
10126 int need_clear = 0;
10127 u64 cache_gen;
10128
10129 root = info->extent_root;
10130 key.objectid = 0;
10131 key.offset = 0;
10132 key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
10133 path = btrfs_alloc_path();
10134 if (!path)
10135 return -ENOMEM;
10136 path->reada = READA_FORWARD;
10137
10138 cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
10139 if (btrfs_test_opt(root->fs_info, SPACE_CACHE) &&
10140 btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
10141 need_clear = 1;
10142 if (btrfs_test_opt(root->fs_info, CLEAR_CACHE))
10143 need_clear = 1;
10144
10145 while (1) {
10146 ret = find_first_block_group(root, path, &key);
10147 if (ret > 0)
10148 break;
10149 if (ret != 0)
10150 goto error;
10151
10152 leaf = path->nodes[0];
10153 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
10154
10155 cache = btrfs_create_block_group_cache(root, found_key.objectid,
10156 found_key.offset);
10157 if (!cache) {
10158 ret = -ENOMEM;
10159 goto error;
10160 }
10161
10162 if (need_clear) {
10163 /*
10164 * When we mount with old space cache, we need to
10165 * set BTRFS_DC_CLEAR and set dirty flag.
10166 *
10167 * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
10168 * truncate the old free space cache inode and
10169 * setup a new one.
10170 * b) Setting 'dirty flag' makes sure that we flush
10171 * the new space cache info onto disk.
10172 */
10173 if (btrfs_test_opt(root->fs_info, SPACE_CACHE))
10174 cache->disk_cache_state = BTRFS_DC_CLEAR;
10175 }
10176
10177 read_extent_buffer(leaf, &cache->item,
10178 btrfs_item_ptr_offset(leaf, path->slots[0]),
10179 sizeof(cache->item));
10180 cache->flags = btrfs_block_group_flags(&cache->item);
10181
10182 key.objectid = found_key.objectid + found_key.offset;
10183 btrfs_release_path(path);
10184
10185 /*
10186 * We need to exclude the super stripes now so that the space
10187 * info has super bytes accounted for, otherwise we'll think
10188 * we have more space than we actually do.
10189 */
10190 ret = exclude_super_stripes(root, cache);
10191 if (ret) {
10192 /*
10193 * We may have excluded something, so call this just in
10194 * case.
10195 */
10196 free_excluded_extents(root, cache);
10197 btrfs_put_block_group(cache);
10198 goto error;
10199 }
10200
10201 /*
10202 * check for two cases, either we are full, and therefore
10203 * don't need to bother with the caching work since we won't
10204 * find any space, or we are empty, and we can just add all
10205 * the space in and be done with it. This saves us _alot_ of
10206 * time, particularly in the full case.
10207 */
10208 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
10209 cache->last_byte_to_unpin = (u64)-1;
10210 cache->cached = BTRFS_CACHE_FINISHED;
10211 free_excluded_extents(root, cache);
10212 } else if (btrfs_block_group_used(&cache->item) == 0) {
10213 cache->last_byte_to_unpin = (u64)-1;
10214 cache->cached = BTRFS_CACHE_FINISHED;
10215 add_new_free_space(cache, root->fs_info,
10216 found_key.objectid,
10217 found_key.objectid +
10218 found_key.offset);
10219 free_excluded_extents(root, cache);
10220 }
10221
10222 ret = btrfs_add_block_group_cache(root->fs_info, cache);
10223 if (ret) {
10224 btrfs_remove_free_space_cache(cache);
10225 btrfs_put_block_group(cache);
10226 goto error;
10227 }
10228
10229 trace_btrfs_add_block_group(root->fs_info, cache, 0);
10230 ret = update_space_info(info, cache->flags, found_key.offset,
10231 btrfs_block_group_used(&cache->item),
10232 cache->bytes_super, &space_info);
10233 if (ret) {
10234 btrfs_remove_free_space_cache(cache);
10235 spin_lock(&info->block_group_cache_lock);
10236 rb_erase(&cache->cache_node,
10237 &info->block_group_cache_tree);
10238 RB_CLEAR_NODE(&cache->cache_node);
10239 spin_unlock(&info->block_group_cache_lock);
10240 btrfs_put_block_group(cache);
10241 goto error;
10242 }
10243
10244 cache->space_info = space_info;
10245
10246 __link_block_group(space_info, cache);
10247
10248 set_avail_alloc_bits(root->fs_info, cache->flags);
10249 if (btrfs_chunk_readonly(root, cache->key.objectid)) {
10250 inc_block_group_ro(cache, 1);
10251 } else if (btrfs_block_group_used(&cache->item) == 0) {
10252 spin_lock(&info->unused_bgs_lock);
10253 /* Should always be true but just in case. */
10254 if (list_empty(&cache->bg_list)) {
10255 btrfs_get_block_group(cache);
10256 list_add_tail(&cache->bg_list,
10257 &info->unused_bgs);
10258 }
10259 spin_unlock(&info->unused_bgs_lock);
10260 }
10261 }
10262
10263 list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
10264 if (!(get_alloc_profile(root, space_info->flags) &
10265 (BTRFS_BLOCK_GROUP_RAID10 |
10266 BTRFS_BLOCK_GROUP_RAID1 |
10267 BTRFS_BLOCK_GROUP_RAID5 |
10268 BTRFS_BLOCK_GROUP_RAID6 |
10269 BTRFS_BLOCK_GROUP_DUP)))
10270 continue;
10271 /*
10272 * avoid allocating from un-mirrored block group if there are
10273 * mirrored block groups.
10274 */
10275 list_for_each_entry(cache,
10276 &space_info->block_groups[BTRFS_RAID_RAID0],
10277 list)
10278 inc_block_group_ro(cache, 1);
10279 list_for_each_entry(cache,
10280 &space_info->block_groups[BTRFS_RAID_SINGLE],
10281 list)
10282 inc_block_group_ro(cache, 1);
10283 }
10284
10285 init_global_block_rsv(info);
10286 ret = 0;
10287 error:
10288 btrfs_free_path(path);
10289 return ret;
10290 }
10291
10292 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
10293 struct btrfs_root *root)
10294 {
10295 struct btrfs_block_group_cache *block_group, *tmp;
10296 struct btrfs_root *extent_root = root->fs_info->extent_root;
10297 struct btrfs_block_group_item item;
10298 struct btrfs_key key;
10299 int ret = 0;
10300 bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
10301
10302 trans->can_flush_pending_bgs = false;
10303 list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
10304 if (ret)
10305 goto next;
10306
10307 spin_lock(&block_group->lock);
10308 memcpy(&item, &block_group->item, sizeof(item));
10309 memcpy(&key, &block_group->key, sizeof(key));
10310 spin_unlock(&block_group->lock);
10311
10312 ret = btrfs_insert_item(trans, extent_root, &key, &item,
10313 sizeof(item));
10314 if (ret)
10315 btrfs_abort_transaction(trans, ret);
10316 ret = btrfs_finish_chunk_alloc(trans, extent_root,
10317 key.objectid, key.offset);
10318 if (ret)
10319 btrfs_abort_transaction(trans, ret);
10320 add_block_group_free_space(trans, root->fs_info, block_group);
10321 /* already aborted the transaction if it failed. */
10322 next:
10323 list_del_init(&block_group->bg_list);
10324 }
10325 trans->can_flush_pending_bgs = can_flush_pending_bgs;
10326 }
10327
10328 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
10329 struct btrfs_root *root, u64 bytes_used,
10330 u64 type, u64 chunk_objectid, u64 chunk_offset,
10331 u64 size)
10332 {
10333 int ret;
10334 struct btrfs_root *extent_root;
10335 struct btrfs_block_group_cache *cache;
10336 extent_root = root->fs_info->extent_root;
10337
10338 btrfs_set_log_full_commit(root->fs_info, trans);
10339
10340 cache = btrfs_create_block_group_cache(root, chunk_offset, size);
10341 if (!cache)
10342 return -ENOMEM;
10343
10344 btrfs_set_block_group_used(&cache->item, bytes_used);
10345 btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
10346 btrfs_set_block_group_flags(&cache->item, type);
10347
10348 cache->flags = type;
10349 cache->last_byte_to_unpin = (u64)-1;
10350 cache->cached = BTRFS_CACHE_FINISHED;
10351 cache->needs_free_space = 1;
10352 ret = exclude_super_stripes(root, cache);
10353 if (ret) {
10354 /*
10355 * We may have excluded something, so call this just in
10356 * case.
10357 */
10358 free_excluded_extents(root, cache);
10359 btrfs_put_block_group(cache);
10360 return ret;
10361 }
10362
10363 add_new_free_space(cache, root->fs_info, chunk_offset,
10364 chunk_offset + size);
10365
10366 free_excluded_extents(root, cache);
10367
10368 #ifdef CONFIG_BTRFS_DEBUG
10369 if (btrfs_should_fragment_free_space(root, cache)) {
10370 u64 new_bytes_used = size - bytes_used;
10371
10372 bytes_used += new_bytes_used >> 1;
10373 fragment_free_space(root, cache);
10374 }
10375 #endif
10376 /*
10377 * Call to ensure the corresponding space_info object is created and
10378 * assigned to our block group, but don't update its counters just yet.
10379 * We want our bg to be added to the rbtree with its ->space_info set.
10380 */
10381 ret = update_space_info(root->fs_info, cache->flags, 0, 0, 0,
10382 &cache->space_info);
10383 if (ret) {
10384 btrfs_remove_free_space_cache(cache);
10385 btrfs_put_block_group(cache);
10386 return ret;
10387 }
10388
10389 ret = btrfs_add_block_group_cache(root->fs_info, cache);
10390 if (ret) {
10391 btrfs_remove_free_space_cache(cache);
10392 btrfs_put_block_group(cache);
10393 return ret;
10394 }
10395
10396 /*
10397 * Now that our block group has its ->space_info set and is inserted in
10398 * the rbtree, update the space info's counters.
10399 */
10400 trace_btrfs_add_block_group(root->fs_info, cache, 1);
10401 ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
10402 cache->bytes_super, &cache->space_info);
10403 if (ret) {
10404 btrfs_remove_free_space_cache(cache);
10405 spin_lock(&root->fs_info->block_group_cache_lock);
10406 rb_erase(&cache->cache_node,
10407 &root->fs_info->block_group_cache_tree);
10408 RB_CLEAR_NODE(&cache->cache_node);
10409 spin_unlock(&root->fs_info->block_group_cache_lock);
10410 btrfs_put_block_group(cache);
10411 return ret;
10412 }
10413 update_global_block_rsv(root->fs_info);
10414
10415 __link_block_group(cache->space_info, cache);
10416
10417 list_add_tail(&cache->bg_list, &trans->new_bgs);
10418
10419 set_avail_alloc_bits(extent_root->fs_info, type);
10420 return 0;
10421 }
10422
10423 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
10424 {
10425 u64 extra_flags = chunk_to_extended(flags) &
10426 BTRFS_EXTENDED_PROFILE_MASK;
10427
10428 write_seqlock(&fs_info->profiles_lock);
10429 if (flags & BTRFS_BLOCK_GROUP_DATA)
10430 fs_info->avail_data_alloc_bits &= ~extra_flags;
10431 if (flags & BTRFS_BLOCK_GROUP_METADATA)
10432 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
10433 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
10434 fs_info->avail_system_alloc_bits &= ~extra_flags;
10435 write_sequnlock(&fs_info->profiles_lock);
10436 }
10437
10438 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
10439 struct btrfs_root *root, u64 group_start,
10440 struct extent_map *em)
10441 {
10442 struct btrfs_path *path;
10443 struct btrfs_block_group_cache *block_group;
10444 struct btrfs_free_cluster *cluster;
10445 struct btrfs_root *tree_root = root->fs_info->tree_root;
10446 struct btrfs_key key;
10447 struct inode *inode;
10448 struct kobject *kobj = NULL;
10449 int ret;
10450 int index;
10451 int factor;
10452 struct btrfs_caching_control *caching_ctl = NULL;
10453 bool remove_em;
10454
10455 root = root->fs_info->extent_root;
10456
10457 block_group = btrfs_lookup_block_group(root->fs_info, group_start);
10458 BUG_ON(!block_group);
10459 BUG_ON(!block_group->ro);
10460
10461 /*
10462 * Free the reserved super bytes from this block group before
10463 * remove it.
10464 */
10465 free_excluded_extents(root, block_group);
10466
10467 memcpy(&key, &block_group->key, sizeof(key));
10468 index = get_block_group_index(block_group);
10469 if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
10470 BTRFS_BLOCK_GROUP_RAID1 |
10471 BTRFS_BLOCK_GROUP_RAID10))
10472 factor = 2;
10473 else
10474 factor = 1;
10475
10476 /* make sure this block group isn't part of an allocation cluster */
10477 cluster = &root->fs_info->data_alloc_cluster;
10478 spin_lock(&cluster->refill_lock);
10479 btrfs_return_cluster_to_free_space(block_group, cluster);
10480 spin_unlock(&cluster->refill_lock);
10481
10482 /*
10483 * make sure this block group isn't part of a metadata
10484 * allocation cluster
10485 */
10486 cluster = &root->fs_info->meta_alloc_cluster;
10487 spin_lock(&cluster->refill_lock);
10488 btrfs_return_cluster_to_free_space(block_group, cluster);
10489 spin_unlock(&cluster->refill_lock);
10490
10491 path = btrfs_alloc_path();
10492 if (!path) {
10493 ret = -ENOMEM;
10494 goto out;
10495 }
10496
10497 /*
10498 * get the inode first so any iput calls done for the io_list
10499 * aren't the final iput (no unlinks allowed now)
10500 */
10501 inode = lookup_free_space_inode(tree_root, block_group, path);
10502
10503 mutex_lock(&trans->transaction->cache_write_mutex);
10504 /*
10505 * make sure our free spache cache IO is done before remove the
10506 * free space inode
10507 */
10508 spin_lock(&trans->transaction->dirty_bgs_lock);
10509 if (!list_empty(&block_group->io_list)) {
10510 list_del_init(&block_group->io_list);
10511
10512 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
10513
10514 spin_unlock(&trans->transaction->dirty_bgs_lock);
10515 btrfs_wait_cache_io(root, trans, block_group,
10516 &block_group->io_ctl, path,
10517 block_group->key.objectid);
10518 btrfs_put_block_group(block_group);
10519 spin_lock(&trans->transaction->dirty_bgs_lock);
10520 }
10521
10522 if (!list_empty(&block_group->dirty_list)) {
10523 list_del_init(&block_group->dirty_list);
10524 btrfs_put_block_group(block_group);
10525 }
10526 spin_unlock(&trans->transaction->dirty_bgs_lock);
10527 mutex_unlock(&trans->transaction->cache_write_mutex);
10528
10529 if (!IS_ERR(inode)) {
10530 ret = btrfs_orphan_add(trans, inode);
10531 if (ret) {
10532 btrfs_add_delayed_iput(inode);
10533 goto out;
10534 }
10535 clear_nlink(inode);
10536 /* One for the block groups ref */
10537 spin_lock(&block_group->lock);
10538 if (block_group->iref) {
10539 block_group->iref = 0;
10540 block_group->inode = NULL;
10541 spin_unlock(&block_group->lock);
10542 iput(inode);
10543 } else {
10544 spin_unlock(&block_group->lock);
10545 }
10546 /* One for our lookup ref */
10547 btrfs_add_delayed_iput(inode);
10548 }
10549
10550 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
10551 key.offset = block_group->key.objectid;
10552 key.type = 0;
10553
10554 ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
10555 if (ret < 0)
10556 goto out;
10557 if (ret > 0)
10558 btrfs_release_path(path);
10559 if (ret == 0) {
10560 ret = btrfs_del_item(trans, tree_root, path);
10561 if (ret)
10562 goto out;
10563 btrfs_release_path(path);
10564 }
10565
10566 spin_lock(&root->fs_info->block_group_cache_lock);
10567 rb_erase(&block_group->cache_node,
10568 &root->fs_info->block_group_cache_tree);
10569 RB_CLEAR_NODE(&block_group->cache_node);
10570
10571 if (root->fs_info->first_logical_byte == block_group->key.objectid)
10572 root->fs_info->first_logical_byte = (u64)-1;
10573 spin_unlock(&root->fs_info->block_group_cache_lock);
10574
10575 down_write(&block_group->space_info->groups_sem);
10576 /*
10577 * we must use list_del_init so people can check to see if they
10578 * are still on the list after taking the semaphore
10579 */
10580 list_del_init(&block_group->list);
10581 if (list_empty(&block_group->space_info->block_groups[index])) {
10582 kobj = block_group->space_info->block_group_kobjs[index];
10583 block_group->space_info->block_group_kobjs[index] = NULL;
10584 clear_avail_alloc_bits(root->fs_info, block_group->flags);
10585 }
10586 up_write(&block_group->space_info->groups_sem);
10587 if (kobj) {
10588 kobject_del(kobj);
10589 kobject_put(kobj);
10590 }
10591
10592 if (block_group->has_caching_ctl)
10593 caching_ctl = get_caching_control(block_group);
10594 if (block_group->cached == BTRFS_CACHE_STARTED)
10595 wait_block_group_cache_done(block_group);
10596 if (block_group->has_caching_ctl) {
10597 down_write(&root->fs_info->commit_root_sem);
10598 if (!caching_ctl) {
10599 struct btrfs_caching_control *ctl;
10600
10601 list_for_each_entry(ctl,
10602 &root->fs_info->caching_block_groups, list)
10603 if (ctl->block_group == block_group) {
10604 caching_ctl = ctl;
10605 atomic_inc(&caching_ctl->count);
10606 break;
10607 }
10608 }
10609 if (caching_ctl)
10610 list_del_init(&caching_ctl->list);
10611 up_write(&root->fs_info->commit_root_sem);
10612 if (caching_ctl) {
10613 /* Once for the caching bgs list and once for us. */
10614 put_caching_control(caching_ctl);
10615 put_caching_control(caching_ctl);
10616 }
10617 }
10618
10619 spin_lock(&trans->transaction->dirty_bgs_lock);
10620 if (!list_empty(&block_group->dirty_list)) {
10621 WARN_ON(1);
10622 }
10623 if (!list_empty(&block_group->io_list)) {
10624 WARN_ON(1);
10625 }
10626 spin_unlock(&trans->transaction->dirty_bgs_lock);
10627 btrfs_remove_free_space_cache(block_group);
10628
10629 spin_lock(&block_group->space_info->lock);
10630 list_del_init(&block_group->ro_list);
10631
10632 if (btrfs_test_opt(root->fs_info, ENOSPC_DEBUG)) {
10633 WARN_ON(block_group->space_info->total_bytes
10634 < block_group->key.offset);
10635 WARN_ON(block_group->space_info->bytes_readonly
10636 < block_group->key.offset);
10637 WARN_ON(block_group->space_info->disk_total
10638 < block_group->key.offset * factor);
10639 }
10640 block_group->space_info->total_bytes -= block_group->key.offset;
10641 block_group->space_info->bytes_readonly -= block_group->key.offset;
10642 block_group->space_info->disk_total -= block_group->key.offset * factor;
10643
10644 spin_unlock(&block_group->space_info->lock);
10645
10646 memcpy(&key, &block_group->key, sizeof(key));
10647
10648 lock_chunks(root);
10649 if (!list_empty(&em->list)) {
10650 /* We're in the transaction->pending_chunks list. */
10651 free_extent_map(em);
10652 }
10653 spin_lock(&block_group->lock);
10654 block_group->removed = 1;
10655 /*
10656 * At this point trimming can't start on this block group, because we
10657 * removed the block group from the tree fs_info->block_group_cache_tree
10658 * so no one can't find it anymore and even if someone already got this
10659 * block group before we removed it from the rbtree, they have already
10660 * incremented block_group->trimming - if they didn't, they won't find
10661 * any free space entries because we already removed them all when we
10662 * called btrfs_remove_free_space_cache().
10663 *
10664 * And we must not remove the extent map from the fs_info->mapping_tree
10665 * to prevent the same logical address range and physical device space
10666 * ranges from being reused for a new block group. This is because our
10667 * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
10668 * completely transactionless, so while it is trimming a range the
10669 * currently running transaction might finish and a new one start,
10670 * allowing for new block groups to be created that can reuse the same
10671 * physical device locations unless we take this special care.
10672 *
10673 * There may also be an implicit trim operation if the file system
10674 * is mounted with -odiscard. The same protections must remain
10675 * in place until the extents have been discarded completely when
10676 * the transaction commit has completed.
10677 */
10678 remove_em = (atomic_read(&block_group->trimming) == 0);
10679 /*
10680 * Make sure a trimmer task always sees the em in the pinned_chunks list
10681 * if it sees block_group->removed == 1 (needs to lock block_group->lock
10682 * before checking block_group->removed).
10683 */
10684 if (!remove_em) {
10685 /*
10686 * Our em might be in trans->transaction->pending_chunks which
10687 * is protected by fs_info->chunk_mutex ([lock|unlock]_chunks),
10688 * and so is the fs_info->pinned_chunks list.
10689 *
10690 * So at this point we must be holding the chunk_mutex to avoid
10691 * any races with chunk allocation (more specifically at
10692 * volumes.c:contains_pending_extent()), to ensure it always
10693 * sees the em, either in the pending_chunks list or in the
10694 * pinned_chunks list.
10695 */
10696 list_move_tail(&em->list, &root->fs_info->pinned_chunks);
10697 }
10698 spin_unlock(&block_group->lock);
10699
10700 if (remove_em) {
10701 struct extent_map_tree *em_tree;
10702
10703 em_tree = &root->fs_info->mapping_tree.map_tree;
10704 write_lock(&em_tree->lock);
10705 /*
10706 * The em might be in the pending_chunks list, so make sure the
10707 * chunk mutex is locked, since remove_extent_mapping() will
10708 * delete us from that list.
10709 */
10710 remove_extent_mapping(em_tree, em);
10711 write_unlock(&em_tree->lock);
10712 /* once for the tree */
10713 free_extent_map(em);
10714 }
10715
10716 unlock_chunks(root);
10717
10718 ret = remove_block_group_free_space(trans, root->fs_info, block_group);
10719 if (ret)
10720 goto out;
10721
10722 btrfs_put_block_group(block_group);
10723 btrfs_put_block_group(block_group);
10724
10725 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
10726 if (ret > 0)
10727 ret = -EIO;
10728 if (ret < 0)
10729 goto out;
10730
10731 ret = btrfs_del_item(trans, root, path);
10732 out:
10733 btrfs_free_path(path);
10734 return ret;
10735 }
10736
10737 struct btrfs_trans_handle *
10738 btrfs_start_trans_remove_block_group(struct btrfs_fs_info *fs_info,
10739 const u64 chunk_offset)
10740 {
10741 struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree;
10742 struct extent_map *em;
10743 struct map_lookup *map;
10744 unsigned int num_items;
10745
10746 read_lock(&em_tree->lock);
10747 em = lookup_extent_mapping(em_tree, chunk_offset, 1);
10748 read_unlock(&em_tree->lock);
10749 ASSERT(em && em->start == chunk_offset);
10750
10751 /*
10752 * We need to reserve 3 + N units from the metadata space info in order
10753 * to remove a block group (done at btrfs_remove_chunk() and at
10754 * btrfs_remove_block_group()), which are used for:
10755 *
10756 * 1 unit for adding the free space inode's orphan (located in the tree
10757 * of tree roots).
10758 * 1 unit for deleting the block group item (located in the extent
10759 * tree).
10760 * 1 unit for deleting the free space item (located in tree of tree
10761 * roots).
10762 * N units for deleting N device extent items corresponding to each
10763 * stripe (located in the device tree).
10764 *
10765 * In order to remove a block group we also need to reserve units in the
10766 * system space info in order to update the chunk tree (update one or
10767 * more device items and remove one chunk item), but this is done at
10768 * btrfs_remove_chunk() through a call to check_system_chunk().
10769 */
10770 map = em->map_lookup;
10771 num_items = 3 + map->num_stripes;
10772 free_extent_map(em);
10773
10774 return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
10775 num_items, 1);
10776 }
10777
10778 /*
10779 * Process the unused_bgs list and remove any that don't have any allocated
10780 * space inside of them.
10781 */
10782 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
10783 {
10784 struct btrfs_block_group_cache *block_group;
10785 struct btrfs_space_info *space_info;
10786 struct btrfs_root *root = fs_info->extent_root;
10787 struct btrfs_trans_handle *trans;
10788 int ret = 0;
10789
10790 if (!fs_info->open)
10791 return;
10792
10793 spin_lock(&fs_info->unused_bgs_lock);
10794 while (!list_empty(&fs_info->unused_bgs)) {
10795 u64 start, end;
10796 int trimming;
10797
10798 block_group = list_first_entry(&fs_info->unused_bgs,
10799 struct btrfs_block_group_cache,
10800 bg_list);
10801 list_del_init(&block_group->bg_list);
10802
10803 space_info = block_group->space_info;
10804
10805 if (ret || btrfs_mixed_space_info(space_info)) {
10806 btrfs_put_block_group(block_group);
10807 continue;
10808 }
10809 spin_unlock(&fs_info->unused_bgs_lock);
10810
10811 mutex_lock(&fs_info->delete_unused_bgs_mutex);
10812
10813 /* Don't want to race with allocators so take the groups_sem */
10814 down_write(&space_info->groups_sem);
10815 spin_lock(&block_group->lock);
10816 if (block_group->reserved ||
10817 btrfs_block_group_used(&block_group->item) ||
10818 block_group->ro ||
10819 list_is_singular(&block_group->list)) {
10820 /*
10821 * We want to bail if we made new allocations or have
10822 * outstanding allocations in this block group. We do
10823 * the ro check in case balance is currently acting on
10824 * this block group.
10825 */
10826 spin_unlock(&block_group->lock);
10827 up_write(&space_info->groups_sem);
10828 goto next;
10829 }
10830 spin_unlock(&block_group->lock);
10831
10832 /* We don't want to force the issue, only flip if it's ok. */
10833 ret = inc_block_group_ro(block_group, 0);
10834 up_write(&space_info->groups_sem);
10835 if (ret < 0) {
10836 ret = 0;
10837 goto next;
10838 }
10839
10840 /*
10841 * Want to do this before we do anything else so we can recover
10842 * properly if we fail to join the transaction.
10843 */
10844 trans = btrfs_start_trans_remove_block_group(fs_info,
10845 block_group->key.objectid);
10846 if (IS_ERR(trans)) {
10847 btrfs_dec_block_group_ro(root, block_group);
10848 ret = PTR_ERR(trans);
10849 goto next;
10850 }
10851
10852 /*
10853 * We could have pending pinned extents for this block group,
10854 * just delete them, we don't care about them anymore.
10855 */
10856 start = block_group->key.objectid;
10857 end = start + block_group->key.offset - 1;
10858 /*
10859 * Hold the unused_bg_unpin_mutex lock to avoid racing with
10860 * btrfs_finish_extent_commit(). If we are at transaction N,
10861 * another task might be running finish_extent_commit() for the
10862 * previous transaction N - 1, and have seen a range belonging
10863 * to the block group in freed_extents[] before we were able to
10864 * clear the whole block group range from freed_extents[]. This
10865 * means that task can lookup for the block group after we
10866 * unpinned it from freed_extents[] and removed it, leading to
10867 * a BUG_ON() at btrfs_unpin_extent_range().
10868 */
10869 mutex_lock(&fs_info->unused_bg_unpin_mutex);
10870 ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
10871 EXTENT_DIRTY);
10872 if (ret) {
10873 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10874 btrfs_dec_block_group_ro(root, block_group);
10875 goto end_trans;
10876 }
10877 ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
10878 EXTENT_DIRTY);
10879 if (ret) {
10880 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10881 btrfs_dec_block_group_ro(root, block_group);
10882 goto end_trans;
10883 }
10884 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10885
10886 /* Reset pinned so btrfs_put_block_group doesn't complain */
10887 spin_lock(&space_info->lock);
10888 spin_lock(&block_group->lock);
10889
10890 space_info->bytes_pinned -= block_group->pinned;
10891 space_info->bytes_readonly += block_group->pinned;
10892 percpu_counter_add(&space_info->total_bytes_pinned,
10893 -block_group->pinned);
10894 block_group->pinned = 0;
10895
10896 spin_unlock(&block_group->lock);
10897 spin_unlock(&space_info->lock);
10898
10899 /* DISCARD can flip during remount */
10900 trimming = btrfs_test_opt(root->fs_info, DISCARD);
10901
10902 /* Implicit trim during transaction commit. */
10903 if (trimming)
10904 btrfs_get_block_group_trimming(block_group);
10905
10906 /*
10907 * Btrfs_remove_chunk will abort the transaction if things go
10908 * horribly wrong.
10909 */
10910 ret = btrfs_remove_chunk(trans, root,
10911 block_group->key.objectid);
10912
10913 if (ret) {
10914 if (trimming)
10915 btrfs_put_block_group_trimming(block_group);
10916 goto end_trans;
10917 }
10918
10919 /*
10920 * If we're not mounted with -odiscard, we can just forget
10921 * about this block group. Otherwise we'll need to wait
10922 * until transaction commit to do the actual discard.
10923 */
10924 if (trimming) {
10925 spin_lock(&fs_info->unused_bgs_lock);
10926 /*
10927 * A concurrent scrub might have added us to the list
10928 * fs_info->unused_bgs, so use a list_move operation
10929 * to add the block group to the deleted_bgs list.
10930 */
10931 list_move(&block_group->bg_list,
10932 &trans->transaction->deleted_bgs);
10933 spin_unlock(&fs_info->unused_bgs_lock);
10934 btrfs_get_block_group(block_group);
10935 }
10936 end_trans:
10937 btrfs_end_transaction(trans, root);
10938 next:
10939 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
10940 btrfs_put_block_group(block_group);
10941 spin_lock(&fs_info->unused_bgs_lock);
10942 }
10943 spin_unlock(&fs_info->unused_bgs_lock);
10944 }
10945
10946 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
10947 {
10948 struct btrfs_space_info *space_info;
10949 struct btrfs_super_block *disk_super;
10950 u64 features;
10951 u64 flags;
10952 int mixed = 0;
10953 int ret;
10954
10955 disk_super = fs_info->super_copy;
10956 if (!btrfs_super_root(disk_super))
10957 return -EINVAL;
10958
10959 features = btrfs_super_incompat_flags(disk_super);
10960 if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
10961 mixed = 1;
10962
10963 flags = BTRFS_BLOCK_GROUP_SYSTEM;
10964 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
10965 if (ret)
10966 goto out;
10967
10968 if (mixed) {
10969 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
10970 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
10971 } else {
10972 flags = BTRFS_BLOCK_GROUP_METADATA;
10973 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
10974 if (ret)
10975 goto out;
10976
10977 flags = BTRFS_BLOCK_GROUP_DATA;
10978 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
10979 }
10980 out:
10981 return ret;
10982 }
10983
10984 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
10985 {
10986 return unpin_extent_range(root, start, end, false);
10987 }
10988
10989 /*
10990 * It used to be that old block groups would be left around forever.
10991 * Iterating over them would be enough to trim unused space. Since we
10992 * now automatically remove them, we also need to iterate over unallocated
10993 * space.
10994 *
10995 * We don't want a transaction for this since the discard may take a
10996 * substantial amount of time. We don't require that a transaction be
10997 * running, but we do need to take a running transaction into account
10998 * to ensure that we're not discarding chunks that were released in
10999 * the current transaction.
11000 *
11001 * Holding the chunks lock will prevent other threads from allocating
11002 * or releasing chunks, but it won't prevent a running transaction
11003 * from committing and releasing the memory that the pending chunks
11004 * list head uses. For that, we need to take a reference to the
11005 * transaction.
11006 */
11007 static int btrfs_trim_free_extents(struct btrfs_device *device,
11008 u64 minlen, u64 *trimmed)
11009 {
11010 u64 start = 0, len = 0;
11011 int ret;
11012
11013 *trimmed = 0;
11014
11015 /* Not writeable = nothing to do. */
11016 if (!device->writeable)
11017 return 0;
11018
11019 /* No free space = nothing to do. */
11020 if (device->total_bytes <= device->bytes_used)
11021 return 0;
11022
11023 ret = 0;
11024
11025 while (1) {
11026 struct btrfs_fs_info *fs_info = device->dev_root->fs_info;
11027 struct btrfs_transaction *trans;
11028 u64 bytes;
11029
11030 ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
11031 if (ret)
11032 return ret;
11033
11034 down_read(&fs_info->commit_root_sem);
11035
11036 spin_lock(&fs_info->trans_lock);
11037 trans = fs_info->running_transaction;
11038 if (trans)
11039 atomic_inc(&trans->use_count);
11040 spin_unlock(&fs_info->trans_lock);
11041
11042 ret = find_free_dev_extent_start(trans, device, minlen, start,
11043 &start, &len);
11044 if (trans)
11045 btrfs_put_transaction(trans);
11046
11047 if (ret) {
11048 up_read(&fs_info->commit_root_sem);
11049 mutex_unlock(&fs_info->chunk_mutex);
11050 if (ret == -ENOSPC)
11051 ret = 0;
11052 break;
11053 }
11054
11055 ret = btrfs_issue_discard(device->bdev, start, len, &bytes);
11056 up_read(&fs_info->commit_root_sem);
11057 mutex_unlock(&fs_info->chunk_mutex);
11058
11059 if (ret)
11060 break;
11061
11062 start += len;
11063 *trimmed += bytes;
11064
11065 if (fatal_signal_pending(current)) {
11066 ret = -ERESTARTSYS;
11067 break;
11068 }
11069
11070 cond_resched();
11071 }
11072
11073 return ret;
11074 }
11075
11076 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
11077 {
11078 struct btrfs_fs_info *fs_info = root->fs_info;
11079 struct btrfs_block_group_cache *cache = NULL;
11080 struct btrfs_device *device;
11081 struct list_head *devices;
11082 u64 group_trimmed;
11083 u64 start;
11084 u64 end;
11085 u64 trimmed = 0;
11086 u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
11087 int ret = 0;
11088
11089 /*
11090 * try to trim all FS space, our block group may start from non-zero.
11091 */
11092 if (range->len == total_bytes)
11093 cache = btrfs_lookup_first_block_group(fs_info, range->start);
11094 else
11095 cache = btrfs_lookup_block_group(fs_info, range->start);
11096
11097 while (cache) {
11098 if (cache->key.objectid >= (range->start + range->len)) {
11099 btrfs_put_block_group(cache);
11100 break;
11101 }
11102
11103 start = max(range->start, cache->key.objectid);
11104 end = min(range->start + range->len,
11105 cache->key.objectid + cache->key.offset);
11106
11107 if (end - start >= range->minlen) {
11108 if (!block_group_cache_done(cache)) {
11109 ret = cache_block_group(cache, 0);
11110 if (ret) {
11111 btrfs_put_block_group(cache);
11112 break;
11113 }
11114 ret = wait_block_group_cache_done(cache);
11115 if (ret) {
11116 btrfs_put_block_group(cache);
11117 break;
11118 }
11119 }
11120 ret = btrfs_trim_block_group(cache,
11121 &group_trimmed,
11122 start,
11123 end,
11124 range->minlen);
11125
11126 trimmed += group_trimmed;
11127 if (ret) {
11128 btrfs_put_block_group(cache);
11129 break;
11130 }
11131 }
11132
11133 cache = next_block_group(fs_info->tree_root, cache);
11134 }
11135
11136 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
11137 devices = &root->fs_info->fs_devices->alloc_list;
11138 list_for_each_entry(device, devices, dev_alloc_list) {
11139 ret = btrfs_trim_free_extents(device, range->minlen,
11140 &group_trimmed);
11141 if (ret)
11142 break;
11143
11144 trimmed += group_trimmed;
11145 }
11146 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
11147
11148 range->len = trimmed;
11149 return ret;
11150 }
11151
11152 /*
11153 * btrfs_{start,end}_write_no_snapshoting() are similar to
11154 * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
11155 * data into the page cache through nocow before the subvolume is snapshoted,
11156 * but flush the data into disk after the snapshot creation, or to prevent
11157 * operations while snapshoting is ongoing and that cause the snapshot to be
11158 * inconsistent (writes followed by expanding truncates for example).
11159 */
11160 void btrfs_end_write_no_snapshoting(struct btrfs_root *root)
11161 {
11162 percpu_counter_dec(&root->subv_writers->counter);
11163 /*
11164 * Make sure counter is updated before we wake up waiters.
11165 */
11166 smp_mb();
11167 if (waitqueue_active(&root->subv_writers->wait))
11168 wake_up(&root->subv_writers->wait);
11169 }
11170
11171 int btrfs_start_write_no_snapshoting(struct btrfs_root *root)
11172 {
11173 if (atomic_read(&root->will_be_snapshoted))
11174 return 0;
11175
11176 percpu_counter_inc(&root->subv_writers->counter);
11177 /*
11178 * Make sure counter is updated before we check for snapshot creation.
11179 */
11180 smp_mb();
11181 if (atomic_read(&root->will_be_snapshoted)) {
11182 btrfs_end_write_no_snapshoting(root);
11183 return 0;
11184 }
11185 return 1;
11186 }
11187
11188 static int wait_snapshoting_atomic_t(atomic_t *a)
11189 {
11190 schedule();
11191 return 0;
11192 }
11193
11194 void btrfs_wait_for_snapshot_creation(struct btrfs_root *root)
11195 {
11196 while (true) {
11197 int ret;
11198
11199 ret = btrfs_start_write_no_snapshoting(root);
11200 if (ret)
11201 break;
11202 wait_on_atomic_t(&root->will_be_snapshoted,
11203 wait_snapshoting_atomic_t,
11204 TASK_UNINTERRUPTIBLE);
11205 }
11206 }
Linux kernel - Deliverables
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