?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[cris-mirror.git] / fs / btrfs / extent-tree.c
blob38c2df84cabd0cf2116239d1cf08d1d18709890f
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 }
3698
3699 btrfs_free_path(path);
3700 return ret;
3701 }
3702
3703 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3704 struct btrfs_root *root)
3705 {
3706 struct btrfs_block_group_cache *cache;
3707 struct btrfs_transaction *cur_trans = trans->transaction;
3708 int ret = 0;
3709 int should_put;
3710 struct btrfs_path *path;
3711 struct list_head *io = &cur_trans->io_bgs;
3712 int num_started = 0;
3713
3714 path = btrfs_alloc_path();
3715 if (!path)
3716 return -ENOMEM;
3717
3718 /*
3719 * Even though we are in the critical section of the transaction commit,
3720 * we can still have concurrent tasks adding elements to this
3721 * transaction's list of dirty block groups. These tasks correspond to
3722 * endio free space workers started when writeback finishes for a
3723 * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
3724 * allocate new block groups as a result of COWing nodes of the root
3725 * tree when updating the free space inode. The writeback for the space
3726 * caches is triggered by an earlier call to
3727 * btrfs_start_dirty_block_groups() and iterations of the following
3728 * loop.
3729 * Also we want to do the cache_save_setup first and then run the
3730 * delayed refs to make sure we have the best chance at doing this all
3731 * in one shot.
3732 */
3733 spin_lock(&cur_trans->dirty_bgs_lock);
3734 while (!list_empty(&cur_trans->dirty_bgs)) {
3735 cache = list_first_entry(&cur_trans->dirty_bgs,
3736 struct btrfs_block_group_cache,
3737 dirty_list);
3738
3739 /*
3740 * this can happen if cache_save_setup re-dirties a block
3741 * group that is already under IO. Just wait for it to
3742 * finish and then do it all again
3743 */
3744 if (!list_empty(&cache->io_list)) {
3745 spin_unlock(&cur_trans->dirty_bgs_lock);
3746 list_del_init(&cache->io_list);
3747 btrfs_wait_cache_io(root, trans, cache,
3748 &cache->io_ctl, path,
3749 cache->key.objectid);
3750 btrfs_put_block_group(cache);
3751 spin_lock(&cur_trans->dirty_bgs_lock);
3752 }
3753
3754 /*
3755 * don't remove from the dirty list until after we've waited
3756 * on any pending IO
3757 */
3758 list_del_init(&cache->dirty_list);
3759 spin_unlock(&cur_trans->dirty_bgs_lock);
3760 should_put = 1;
3761
3762 cache_save_setup(cache, trans, path);
3763
3764 if (!ret)
3765 ret = btrfs_run_delayed_refs(trans, root, (unsigned long) -1);
3766
3767 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
3768 cache->io_ctl.inode = NULL;
3769 ret = btrfs_write_out_cache(root, trans, cache, path);
3770 if (ret == 0 && cache->io_ctl.inode) {
3771 num_started++;
3772 should_put = 0;
3773 list_add_tail(&cache->io_list, io);
3774 } else {
3775 /*
3776 * if we failed to write the cache, the
3777 * generation will be bad and life goes on
3778 */
3779 ret = 0;
3780 }
3781 }
3782 if (!ret) {
3783 ret = write_one_cache_group(trans, root, path, cache);
3784 /*
3785 * One of the free space endio workers might have
3786 * created a new block group while updating a free space
3787 * cache's inode (at inode.c:btrfs_finish_ordered_io())
3788 * and hasn't released its transaction handle yet, in
3789 * which case the new block group is still attached to
3790 * its transaction handle and its creation has not
3791 * finished yet (no block group item in the extent tree
3792 * yet, etc). If this is the case, wait for all free
3793 * space endio workers to finish and retry. This is a
3794 * a very rare case so no need for a more efficient and
3795 * complex approach.
3796 */
3797 if (ret == -ENOENT) {
3798 wait_event(cur_trans->writer_wait,
3799 atomic_read(&cur_trans->num_writers) == 1);
3800 ret = write_one_cache_group(trans, root, path,
3801 cache);
3802 }
3803 if (ret)
3804 btrfs_abort_transaction(trans, ret);
3805 }
3806
3807 /* if its not on the io list, we need to put the block group */
3808 if (should_put)
3809 btrfs_put_block_group(cache);
3810 spin_lock(&cur_trans->dirty_bgs_lock);
3811 }
3812 spin_unlock(&cur_trans->dirty_bgs_lock);
3813
3814 while (!list_empty(io)) {
3815 cache = list_first_entry(io, struct btrfs_block_group_cache,
3816 io_list);
3817 list_del_init(&cache->io_list);
3818 btrfs_wait_cache_io(root, trans, cache,
3819 &cache->io_ctl, path, cache->key.objectid);
3820 btrfs_put_block_group(cache);
3821 }
3822
3823 btrfs_free_path(path);
3824 return ret;
3825 }
3826
3827 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3828 {
3829 struct btrfs_block_group_cache *block_group;
3830 int readonly = 0;
3831
3832 block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3833 if (!block_group || block_group->ro)
3834 readonly = 1;
3835 if (block_group)
3836 btrfs_put_block_group(block_group);
3837 return readonly;
3838 }
3839
3840 bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3841 {
3842 struct btrfs_block_group_cache *bg;
3843 bool ret = true;
3844
3845 bg = btrfs_lookup_block_group(fs_info, bytenr);
3846 if (!bg)
3847 return false;
3848
3849 spin_lock(&bg->lock);
3850 if (bg->ro)
3851 ret = false;
3852 else
3853 atomic_inc(&bg->nocow_writers);
3854 spin_unlock(&bg->lock);
3855
3856 /* no put on block group, done by btrfs_dec_nocow_writers */
3857 if (!ret)
3858 btrfs_put_block_group(bg);
3859
3860 return ret;
3861
3862 }
3863
3864 void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3865 {
3866 struct btrfs_block_group_cache *bg;
3867
3868 bg = btrfs_lookup_block_group(fs_info, bytenr);
3869 ASSERT(bg);
3870 if (atomic_dec_and_test(&bg->nocow_writers))
3871 wake_up_atomic_t(&bg->nocow_writers);
3872 /*
3873 * Once for our lookup and once for the lookup done by a previous call
3874 * to btrfs_inc_nocow_writers()
3875 */
3876 btrfs_put_block_group(bg);
3877 btrfs_put_block_group(bg);
3878 }
3879
3880 static int btrfs_wait_nocow_writers_atomic_t(atomic_t *a)
3881 {
3882 schedule();
3883 return 0;
3884 }
3885
3886 void btrfs_wait_nocow_writers(struct btrfs_block_group_cache *bg)
3887 {
3888 wait_on_atomic_t(&bg->nocow_writers,
3889 btrfs_wait_nocow_writers_atomic_t,
3890 TASK_UNINTERRUPTIBLE);
3891 }
3892
3893 static const char *alloc_name(u64 flags)
3894 {
3895 switch (flags) {
3896 case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
3897 return "mixed";
3898 case BTRFS_BLOCK_GROUP_METADATA:
3899 return "metadata";
3900 case BTRFS_BLOCK_GROUP_DATA:
3901 return "data";
3902 case BTRFS_BLOCK_GROUP_SYSTEM:
3903 return "system";
3904 default:
3905 WARN_ON(1);
3906 return "invalid-combination";
3907 };
3908 }
3909
3910 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3911 u64 total_bytes, u64 bytes_used,
3912 u64 bytes_readonly,
3913 struct btrfs_space_info **space_info)
3914 {
3915 struct btrfs_space_info *found;
3916 int i;
3917 int factor;
3918 int ret;
3919
3920 if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3921 BTRFS_BLOCK_GROUP_RAID10))
3922 factor = 2;
3923 else
3924 factor = 1;
3925
3926 found = __find_space_info(info, flags);
3927 if (found) {
3928 spin_lock(&found->lock);
3929 found->total_bytes += total_bytes;
3930 found->disk_total += total_bytes * factor;
3931 found->bytes_used += bytes_used;
3932 found->disk_used += bytes_used * factor;
3933 found->bytes_readonly += bytes_readonly;
3934 if (total_bytes > 0)
3935 found->full = 0;
3936 space_info_add_new_bytes(info, found, total_bytes -
3937 bytes_used - bytes_readonly);
3938 spin_unlock(&found->lock);
3939 *space_info = found;
3940 return 0;
3941 }
3942 found = kzalloc(sizeof(*found), GFP_NOFS);
3943 if (!found)
3944 return -ENOMEM;
3945
3946 ret = percpu_counter_init(&found->total_bytes_pinned, 0, GFP_KERNEL);
3947 if (ret) {
3948 kfree(found);
3949 return ret;
3950 }
3951
3952 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3953 INIT_LIST_HEAD(&found->block_groups[i]);
3954 init_rwsem(&found->groups_sem);
3955 spin_lock_init(&found->lock);
3956 found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3957 found->total_bytes = total_bytes;
3958 found->disk_total = total_bytes * factor;
3959 found->bytes_used = bytes_used;
3960 found->disk_used = bytes_used * factor;
3961 found->bytes_pinned = 0;
3962 found->bytes_reserved = 0;
3963 found->bytes_readonly = bytes_readonly;
3964 found->bytes_may_use = 0;
3965 found->full = 0;
3966 found->max_extent_size = 0;
3967 found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3968 found->chunk_alloc = 0;
3969 found->flush = 0;
3970 init_waitqueue_head(&found->wait);
3971 INIT_LIST_HEAD(&found->ro_bgs);
3972 INIT_LIST_HEAD(&found->tickets);
3973 INIT_LIST_HEAD(&found->priority_tickets);
3974
3975 ret = kobject_init_and_add(&found->kobj, &space_info_ktype,
3976 info->space_info_kobj, "%s",
3977 alloc_name(found->flags));
3978 if (ret) {
3979 kfree(found);
3980 return ret;
3981 }
3982
3983 *space_info = found;
3984 list_add_rcu(&found->list, &info->space_info);
3985 if (flags & BTRFS_BLOCK_GROUP_DATA)
3986 info->data_sinfo = found;
3987
3988 return ret;
3989 }
3990
3991 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3992 {
3993 u64 extra_flags = chunk_to_extended(flags) &
3994 BTRFS_EXTENDED_PROFILE_MASK;
3995
3996 write_seqlock(&fs_info->profiles_lock);
3997 if (flags & BTRFS_BLOCK_GROUP_DATA)
3998 fs_info->avail_data_alloc_bits |= extra_flags;
3999 if (flags & BTRFS_BLOCK_GROUP_METADATA)
4000 fs_info->avail_metadata_alloc_bits |= extra_flags;
4001 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4002 fs_info->avail_system_alloc_bits |= extra_flags;
4003 write_sequnlock(&fs_info->profiles_lock);
4004 }
4005
4006 /*
4007 * returns target flags in extended format or 0 if restripe for this
4008 * chunk_type is not in progress
4009 *
4010 * should be called with either volume_mutex or balance_lock held
4011 */
4012 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
4013 {
4014 struct btrfs_balance_control *bctl = fs_info->balance_ctl;
4015 u64 target = 0;
4016
4017 if (!bctl)
4018 return 0;
4019
4020 if (flags & BTRFS_BLOCK_GROUP_DATA &&
4021 bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4022 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
4023 } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
4024 bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4025 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
4026 } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
4027 bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4028 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
4029 }
4030
4031 return target;
4032 }
4033
4034 /*
4035 * @flags: available profiles in extended format (see ctree.h)
4036 *
4037 * Returns reduced profile in chunk format. If profile changing is in
4038 * progress (either running or paused) picks the target profile (if it's
4039 * already available), otherwise falls back to plain reducing.
4040 */
4041 static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
4042 {
4043 u64 num_devices = root->fs_info->fs_devices->rw_devices;
4044 u64 target;
4045 u64 raid_type;
4046 u64 allowed = 0;
4047
4048 /*
4049 * see if restripe for this chunk_type is in progress, if so
4050 * try to reduce to the target profile
4051 */
4052 spin_lock(&root->fs_info->balance_lock);
4053 target = get_restripe_target(root->fs_info, flags);
4054 if (target) {
4055 /* pick target profile only if it's already available */
4056 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
4057 spin_unlock(&root->fs_info->balance_lock);
4058 return extended_to_chunk(target);
4059 }
4060 }
4061 spin_unlock(&root->fs_info->balance_lock);
4062
4063 /* First, mask out the RAID levels which aren't possible */
4064 for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
4065 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
4066 allowed |= btrfs_raid_group[raid_type];
4067 }
4068 allowed &= flags;
4069
4070 if (allowed & BTRFS_BLOCK_GROUP_RAID6)
4071 allowed = BTRFS_BLOCK_GROUP_RAID6;
4072 else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
4073 allowed = BTRFS_BLOCK_GROUP_RAID5;
4074 else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
4075 allowed = BTRFS_BLOCK_GROUP_RAID10;
4076 else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
4077 allowed = BTRFS_BLOCK_GROUP_RAID1;
4078 else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
4079 allowed = BTRFS_BLOCK_GROUP_RAID0;
4080
4081 flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
4082
4083 return extended_to_chunk(flags | allowed);
4084 }
4085
4086 static u64 get_alloc_profile(struct btrfs_root *root, u64 orig_flags)
4087 {
4088 unsigned seq;
4089 u64 flags;
4090
4091 do {
4092 flags = orig_flags;
4093 seq = read_seqbegin(&root->fs_info->profiles_lock);
4094
4095 if (flags & BTRFS_BLOCK_GROUP_DATA)
4096 flags |= root->fs_info->avail_data_alloc_bits;
4097 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4098 flags |= root->fs_info->avail_system_alloc_bits;
4099 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
4100 flags |= root->fs_info->avail_metadata_alloc_bits;
4101 } while (read_seqretry(&root->fs_info->profiles_lock, seq));
4102
4103 return btrfs_reduce_alloc_profile(root, flags);
4104 }
4105
4106 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
4107 {
4108 u64 flags;
4109 u64 ret;
4110
4111 if (data)
4112 flags = BTRFS_BLOCK_GROUP_DATA;
4113 else if (root == root->fs_info->chunk_root)
4114 flags = BTRFS_BLOCK_GROUP_SYSTEM;
4115 else
4116 flags = BTRFS_BLOCK_GROUP_METADATA;
4117
4118 ret = get_alloc_profile(root, flags);
4119 return ret;
4120 }
4121
4122 int btrfs_alloc_data_chunk_ondemand(struct inode *inode, u64 bytes)
4123 {
4124 struct btrfs_space_info *data_sinfo;
4125 struct btrfs_root *root = BTRFS_I(inode)->root;
4126 struct btrfs_fs_info *fs_info = root->fs_info;
4127 u64 used;
4128 int ret = 0;
4129 int need_commit = 2;
4130 int have_pinned_space;
4131
4132 /* make sure bytes are sectorsize aligned */
4133 bytes = ALIGN(bytes, root->sectorsize);
4134
4135 if (btrfs_is_free_space_inode(inode)) {
4136 need_commit = 0;
4137 ASSERT(current->journal_info);
4138 }
4139
4140 data_sinfo = fs_info->data_sinfo;
4141 if (!data_sinfo)
4142 goto alloc;
4143
4144 again:
4145 /* make sure we have enough space to handle the data first */
4146 spin_lock(&data_sinfo->lock);
4147 used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
4148 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
4149 data_sinfo->bytes_may_use;
4150
4151 if (used + bytes > data_sinfo->total_bytes) {
4152 struct btrfs_trans_handle *trans;
4153
4154 /*
4155 * if we don't have enough free bytes in this space then we need
4156 * to alloc a new chunk.
4157 */
4158 if (!data_sinfo->full) {
4159 u64 alloc_target;
4160
4161 data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
4162 spin_unlock(&data_sinfo->lock);
4163 alloc:
4164 alloc_target = btrfs_get_alloc_profile(root, 1);
4165 /*
4166 * It is ugly that we don't call nolock join
4167 * transaction for the free space inode case here.
4168 * But it is safe because we only do the data space
4169 * reservation for the free space cache in the
4170 * transaction context, the common join transaction
4171 * just increase the counter of the current transaction
4172 * handler, doesn't try to acquire the trans_lock of
4173 * the fs.
4174 */
4175 trans = btrfs_join_transaction(root);
4176 if (IS_ERR(trans))
4177 return PTR_ERR(trans);
4178
4179 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4180 alloc_target,
4181 CHUNK_ALLOC_NO_FORCE);
4182 btrfs_end_transaction(trans, root);
4183 if (ret < 0) {
4184 if (ret != -ENOSPC)
4185 return ret;
4186 else {
4187 have_pinned_space = 1;
4188 goto commit_trans;
4189 }
4190 }
4191
4192 if (!data_sinfo)
4193 data_sinfo = fs_info->data_sinfo;
4194
4195 goto again;
4196 }
4197
4198 /*
4199 * If we don't have enough pinned space to deal with this
4200 * allocation, and no removed chunk in current transaction,
4201 * don't bother committing the transaction.
4202 */
4203 have_pinned_space = percpu_counter_compare(
4204 &data_sinfo->total_bytes_pinned,
4205 used + bytes - data_sinfo->total_bytes);
4206 spin_unlock(&data_sinfo->lock);
4207
4208 /* commit the current transaction and try again */
4209 commit_trans:
4210 if (need_commit &&
4211 !atomic_read(&root->fs_info->open_ioctl_trans)) {
4212 need_commit--;
4213
4214 if (need_commit > 0) {
4215 btrfs_start_delalloc_roots(fs_info, 0, -1);
4216 btrfs_wait_ordered_roots(fs_info, -1, 0, (u64)-1);
4217 }
4218
4219 trans = btrfs_join_transaction(root);
4220 if (IS_ERR(trans))
4221 return PTR_ERR(trans);
4222 if (have_pinned_space >= 0 ||
4223 test_bit(BTRFS_TRANS_HAVE_FREE_BGS,
4224 &trans->transaction->flags) ||
4225 need_commit > 0) {
4226 ret = btrfs_commit_transaction(trans, root);
4227 if (ret)
4228 return ret;
4229 /*
4230 * The cleaner kthread might still be doing iput
4231 * operations. Wait for it to finish so that
4232 * more space is released.
4233 */
4234 mutex_lock(&root->fs_info->cleaner_delayed_iput_mutex);
4235 mutex_unlock(&root->fs_info->cleaner_delayed_iput_mutex);
4236 goto again;
4237 } else {
4238 btrfs_end_transaction(trans, root);
4239 }
4240 }
4241
4242 trace_btrfs_space_reservation(root->fs_info,
4243 "space_info:enospc",
4244 data_sinfo->flags, bytes, 1);
4245 return -ENOSPC;
4246 }
4247 data_sinfo->bytes_may_use += bytes;
4248 trace_btrfs_space_reservation(root->fs_info, "space_info",
4249 data_sinfo->flags, bytes, 1);
4250 spin_unlock(&data_sinfo->lock);
4251
4252 return ret;
4253 }
4254
4255 /*
4256 * New check_data_free_space() with ability for precious data reservation
4257 * Will replace old btrfs_check_data_free_space(), but for patch split,
4258 * add a new function first and then replace it.
4259 */
4260 int btrfs_check_data_free_space(struct inode *inode, u64 start, u64 len)
4261 {
4262 struct btrfs_root *root = BTRFS_I(inode)->root;
4263 int ret;
4264
4265 /* align the range */
4266 len = round_up(start + len, root->sectorsize) -
4267 round_down(start, root->sectorsize);
4268 start = round_down(start, root->sectorsize);
4269
4270 ret = btrfs_alloc_data_chunk_ondemand(inode, len);
4271 if (ret < 0)
4272 return ret;
4273
4274 /*
4275 * Use new btrfs_qgroup_reserve_data to reserve precious data space
4276 *
4277 * TODO: Find a good method to avoid reserve data space for NOCOW
4278 * range, but don't impact performance on quota disable case.
4279 */
4280 ret = btrfs_qgroup_reserve_data(inode, start, len);
4281 return ret;
4282 }
4283
4284 /*
4285 * Called if we need to clear a data reservation for this inode
4286 * Normally in a error case.
4287 *
4288 * This one will *NOT* use accurate qgroup reserved space API, just for case
4289 * which we can't sleep and is sure it won't affect qgroup reserved space.
4290 * Like clear_bit_hook().
4291 */
4292 void btrfs_free_reserved_data_space_noquota(struct inode *inode, u64 start,
4293 u64 len)
4294 {
4295 struct btrfs_root *root = BTRFS_I(inode)->root;
4296 struct btrfs_space_info *data_sinfo;
4297
4298 /* Make sure the range is aligned to sectorsize */
4299 len = round_up(start + len, root->sectorsize) -
4300 round_down(start, root->sectorsize);
4301 start = round_down(start, root->sectorsize);
4302
4303 data_sinfo = root->fs_info->data_sinfo;
4304 spin_lock(&data_sinfo->lock);
4305 if (WARN_ON(data_sinfo->bytes_may_use < len))
4306 data_sinfo->bytes_may_use = 0;
4307 else
4308 data_sinfo->bytes_may_use -= len;
4309 trace_btrfs_space_reservation(root->fs_info, "space_info",
4310 data_sinfo->flags, len, 0);
4311 spin_unlock(&data_sinfo->lock);
4312 }
4313
4314 /*
4315 * Called if we need to clear a data reservation for this inode
4316 * Normally in a error case.
4317 *
4318 * This one will handle the per-inode data rsv map for accurate reserved
4319 * space framework.
4320 */
4321 void btrfs_free_reserved_data_space(struct inode *inode, u64 start, u64 len)
4322 {
4323 btrfs_free_reserved_data_space_noquota(inode, start, len);
4324 btrfs_qgroup_free_data(inode, start, len);
4325 }
4326
4327 static void force_metadata_allocation(struct btrfs_fs_info *info)
4328 {
4329 struct list_head *head = &info->space_info;
4330 struct btrfs_space_info *found;
4331
4332 rcu_read_lock();
4333 list_for_each_entry_rcu(found, head, list) {
4334 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
4335 found->force_alloc = CHUNK_ALLOC_FORCE;
4336 }
4337 rcu_read_unlock();
4338 }
4339
4340 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
4341 {
4342 return (global->size << 1);
4343 }
4344
4345 static int should_alloc_chunk(struct btrfs_root *root,
4346 struct btrfs_space_info *sinfo, int force)
4347 {
4348 struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4349 u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
4350 u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
4351 u64 thresh;
4352
4353 if (force == CHUNK_ALLOC_FORCE)
4354 return 1;
4355
4356 /*
4357 * We need to take into account the global rsv because for all intents
4358 * and purposes it's used space. Don't worry about locking the
4359 * global_rsv, it doesn't change except when the transaction commits.
4360 */
4361 if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
4362 num_allocated += calc_global_rsv_need_space(global_rsv);
4363
4364 /*
4365 * in limited mode, we want to have some free space up to
4366 * about 1% of the FS size.
4367 */
4368 if (force == CHUNK_ALLOC_LIMITED) {
4369 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
4370 thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
4371
4372 if (num_bytes - num_allocated < thresh)
4373 return 1;
4374 }
4375
4376 if (num_allocated + SZ_2M < div_factor(num_bytes, 8))
4377 return 0;
4378 return 1;
4379 }
4380
4381 static u64 get_profile_num_devs(struct btrfs_root *root, u64 type)
4382 {
4383 u64 num_dev;
4384
4385 if (type & (BTRFS_BLOCK_GROUP_RAID10 |
4386 BTRFS_BLOCK_GROUP_RAID0 |
4387 BTRFS_BLOCK_GROUP_RAID5 |
4388 BTRFS_BLOCK_GROUP_RAID6))
4389 num_dev = root->fs_info->fs_devices->rw_devices;
4390 else if (type & BTRFS_BLOCK_GROUP_RAID1)
4391 num_dev = 2;
4392 else
4393 num_dev = 1; /* DUP or single */
4394
4395 return num_dev;
4396 }
4397
4398 /*
4399 * If @is_allocation is true, reserve space in the system space info necessary
4400 * for allocating a chunk, otherwise if it's false, reserve space necessary for
4401 * removing a chunk.
4402 */
4403 void check_system_chunk(struct btrfs_trans_handle *trans,
4404 struct btrfs_root *root,
4405 u64 type)
4406 {
4407 struct btrfs_space_info *info;
4408 u64 left;
4409 u64 thresh;
4410 int ret = 0;
4411 u64 num_devs;
4412
4413 /*
4414 * Needed because we can end up allocating a system chunk and for an
4415 * atomic and race free space reservation in the chunk block reserve.
4416 */
4417 ASSERT(mutex_is_locked(&root->fs_info->chunk_mutex));
4418
4419 info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4420 spin_lock(&info->lock);
4421 left = info->total_bytes - info->bytes_used - info->bytes_pinned -
4422 info->bytes_reserved - info->bytes_readonly -
4423 info->bytes_may_use;
4424 spin_unlock(&info->lock);
4425
4426 num_devs = get_profile_num_devs(root, type);
4427
4428 /* num_devs device items to update and 1 chunk item to add or remove */
4429 thresh = btrfs_calc_trunc_metadata_size(root, num_devs) +
4430 btrfs_calc_trans_metadata_size(root, 1);
4431
4432 if (left < thresh && btrfs_test_opt(root->fs_info, ENOSPC_DEBUG)) {
4433 btrfs_info(root->fs_info, "left=%llu, need=%llu, flags=%llu",
4434 left, thresh, type);
4435 dump_space_info(info, 0, 0);
4436 }
4437
4438 if (left < thresh) {
4439 u64 flags;
4440
4441 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
4442 /*
4443 * Ignore failure to create system chunk. We might end up not
4444 * needing it, as we might not need to COW all nodes/leafs from
4445 * the paths we visit in the chunk tree (they were already COWed
4446 * or created in the current transaction for example).
4447 */
4448 ret = btrfs_alloc_chunk(trans, root, flags);
4449 }
4450
4451 if (!ret) {
4452 ret = btrfs_block_rsv_add(root->fs_info->chunk_root,
4453 &root->fs_info->chunk_block_rsv,
4454 thresh, BTRFS_RESERVE_NO_FLUSH);
4455 if (!ret)
4456 trans->chunk_bytes_reserved += thresh;
4457 }
4458 }
4459
4460 /*
4461 * If force is CHUNK_ALLOC_FORCE:
4462 * - return 1 if it successfully allocates a chunk,
4463 * - return errors including -ENOSPC otherwise.
4464 * If force is NOT CHUNK_ALLOC_FORCE:
4465 * - return 0 if it doesn't need to allocate a new chunk,
4466 * - return 1 if it successfully allocates a chunk,
4467 * - return errors including -ENOSPC otherwise.
4468 */
4469 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
4470 struct btrfs_root *extent_root, u64 flags, int force)
4471 {
4472 struct btrfs_space_info *space_info;
4473 struct btrfs_fs_info *fs_info = extent_root->fs_info;
4474 int wait_for_alloc = 0;
4475 int ret = 0;
4476
4477 /* Don't re-enter if we're already allocating a chunk */
4478 if (trans->allocating_chunk)
4479 return -ENOSPC;
4480
4481 space_info = __find_space_info(extent_root->fs_info, flags);
4482 if (!space_info) {
4483 ret = update_space_info(extent_root->fs_info, flags,
4484 0, 0, 0, &space_info);
4485 BUG_ON(ret); /* -ENOMEM */
4486 }
4487 BUG_ON(!space_info); /* Logic error */
4488
4489 again:
4490 spin_lock(&space_info->lock);
4491 if (force < space_info->force_alloc)
4492 force = space_info->force_alloc;
4493 if (space_info->full) {
4494 if (should_alloc_chunk(extent_root, space_info, force))
4495 ret = -ENOSPC;
4496 else
4497 ret = 0;
4498 spin_unlock(&space_info->lock);
4499 return ret;
4500 }
4501
4502 if (!should_alloc_chunk(extent_root, space_info, force)) {
4503 spin_unlock(&space_info->lock);
4504 return 0;
4505 } else if (space_info->chunk_alloc) {
4506 wait_for_alloc = 1;
4507 } else {
4508 space_info->chunk_alloc = 1;
4509 }
4510
4511 spin_unlock(&space_info->lock);
4512
4513 mutex_lock(&fs_info->chunk_mutex);
4514
4515 /*
4516 * The chunk_mutex is held throughout the entirety of a chunk
4517 * allocation, so once we've acquired the chunk_mutex we know that the
4518 * other guy is done and we need to recheck and see if we should
4519 * allocate.
4520 */
4521 if (wait_for_alloc) {
4522 mutex_unlock(&fs_info->chunk_mutex);
4523 wait_for_alloc = 0;
4524 goto again;
4525 }
4526
4527 trans->allocating_chunk = true;
4528
4529 /*
4530 * If we have mixed data/metadata chunks we want to make sure we keep
4531 * allocating mixed chunks instead of individual chunks.
4532 */
4533 if (btrfs_mixed_space_info(space_info))
4534 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
4535
4536 /*
4537 * if we're doing a data chunk, go ahead and make sure that
4538 * we keep a reasonable number of metadata chunks allocated in the
4539 * FS as well.
4540 */
4541 if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
4542 fs_info->data_chunk_allocations++;
4543 if (!(fs_info->data_chunk_allocations %
4544 fs_info->metadata_ratio))
4545 force_metadata_allocation(fs_info);
4546 }
4547
4548 /*
4549 * Check if we have enough space in SYSTEM chunk because we may need
4550 * to update devices.
4551 */
4552 check_system_chunk(trans, extent_root, flags);
4553
4554 ret = btrfs_alloc_chunk(trans, extent_root, flags);
4555 trans->allocating_chunk = false;
4556
4557 spin_lock(&space_info->lock);
4558 if (ret < 0 && ret != -ENOSPC)
4559 goto out;
4560 if (ret)
4561 space_info->full = 1;
4562 else
4563 ret = 1;
4564
4565 space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4566 out:
4567 space_info->chunk_alloc = 0;
4568 spin_unlock(&space_info->lock);
4569 mutex_unlock(&fs_info->chunk_mutex);
4570 /*
4571 * When we allocate a new chunk we reserve space in the chunk block
4572 * reserve to make sure we can COW nodes/leafs in the chunk tree or
4573 * add new nodes/leafs to it if we end up needing to do it when
4574 * inserting the chunk item and updating device items as part of the
4575 * second phase of chunk allocation, performed by
4576 * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
4577 * large number of new block groups to create in our transaction
4578 * handle's new_bgs list to avoid exhausting the chunk block reserve
4579 * in extreme cases - like having a single transaction create many new
4580 * block groups when starting to write out the free space caches of all
4581 * the block groups that were made dirty during the lifetime of the
4582 * transaction.
4583 */
4584 if (trans->can_flush_pending_bgs &&
4585 trans->chunk_bytes_reserved >= (u64)SZ_2M) {
4586 btrfs_create_pending_block_groups(trans, extent_root);
4587 btrfs_trans_release_chunk_metadata(trans);
4588 }
4589 return ret;
4590 }
4591
4592 static int can_overcommit(struct btrfs_root *root,
4593 struct btrfs_space_info *space_info, u64 bytes,
4594 enum btrfs_reserve_flush_enum flush)
4595 {
4596 struct btrfs_block_rsv *global_rsv;
4597 u64 profile;
4598 u64 space_size;
4599 u64 avail;
4600 u64 used;
4601
4602 /* Don't overcommit when in mixed mode. */
4603 if (space_info->flags & BTRFS_BLOCK_GROUP_DATA)
4604 return 0;
4605
4606 BUG_ON(root->fs_info == NULL);
4607 global_rsv = &root->fs_info->global_block_rsv;
4608 profile = btrfs_get_alloc_profile(root, 0);
4609 used = space_info->bytes_used + space_info->bytes_reserved +
4610 space_info->bytes_pinned + space_info->bytes_readonly;
4611
4612 /*
4613 * We only want to allow over committing if we have lots of actual space
4614 * free, but if we don't have enough space to handle the global reserve
4615 * space then we could end up having a real enospc problem when trying
4616 * to allocate a chunk or some other such important allocation.
4617 */
4618 spin_lock(&global_rsv->lock);
4619 space_size = calc_global_rsv_need_space(global_rsv);
4620 spin_unlock(&global_rsv->lock);
4621 if (used + space_size >= space_info->total_bytes)
4622 return 0;
4623
4624 used += space_info->bytes_may_use;
4625
4626 spin_lock(&root->fs_info->free_chunk_lock);
4627 avail = root->fs_info->free_chunk_space;
4628 spin_unlock(&root->fs_info->free_chunk_lock);
4629
4630 /*
4631 * If we have dup, raid1 or raid10 then only half of the free
4632 * space is actually useable. For raid56, the space info used
4633 * doesn't include the parity drive, so we don't have to
4634 * change the math
4635 */
4636 if (profile & (BTRFS_BLOCK_GROUP_DUP |
4637 BTRFS_BLOCK_GROUP_RAID1 |
4638 BTRFS_BLOCK_GROUP_RAID10))
4639 avail >>= 1;
4640
4641 /*
4642 * If we aren't flushing all things, let us overcommit up to
4643 * 1/2th of the space. If we can flush, don't let us overcommit
4644 * too much, let it overcommit up to 1/8 of the space.
4645 */
4646 if (flush == BTRFS_RESERVE_FLUSH_ALL)
4647 avail >>= 3;
4648 else
4649 avail >>= 1;
4650
4651 if (used + bytes < space_info->total_bytes + avail)
4652 return 1;
4653 return 0;
4654 }
4655
4656 static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
4657 unsigned long nr_pages, int nr_items)
4658 {
4659 struct super_block *sb = root->fs_info->sb;
4660
4661 if (down_read_trylock(&sb->s_umount)) {
4662 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
4663 up_read(&sb->s_umount);
4664 } else {
4665 /*
4666 * We needn't worry the filesystem going from r/w to r/o though
4667 * we don't acquire ->s_umount mutex, because the filesystem
4668 * should guarantee the delalloc inodes list be empty after
4669 * the filesystem is readonly(all dirty pages are written to
4670 * the disk).
4671 */
4672 btrfs_start_delalloc_roots(root->fs_info, 0, nr_items);
4673 if (!current->journal_info)
4674 btrfs_wait_ordered_roots(root->fs_info, nr_items,
4675 0, (u64)-1);
4676 }
4677 }
4678
4679 static inline int calc_reclaim_items_nr(struct btrfs_root *root, u64 to_reclaim)
4680 {
4681 u64 bytes;
4682 int nr;
4683
4684 bytes = btrfs_calc_trans_metadata_size(root, 1);
4685 nr = (int)div64_u64(to_reclaim, bytes);
4686 if (!nr)
4687 nr = 1;
4688 return nr;
4689 }
4690
4691 #define EXTENT_SIZE_PER_ITEM SZ_256K
4692
4693 /*
4694 * shrink metadata reservation for delalloc
4695 */
4696 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
4697 bool wait_ordered)
4698 {
4699 struct btrfs_block_rsv *block_rsv;
4700 struct btrfs_space_info *space_info;
4701 struct btrfs_trans_handle *trans;
4702 u64 delalloc_bytes;
4703 u64 max_reclaim;
4704 long time_left;
4705 unsigned long nr_pages;
4706 int loops;
4707 int items;
4708 enum btrfs_reserve_flush_enum flush;
4709
4710 /* Calc the number of the pages we need flush for space reservation */
4711 items = calc_reclaim_items_nr(root, to_reclaim);
4712 to_reclaim = (u64)items * EXTENT_SIZE_PER_ITEM;
4713
4714 trans = (struct btrfs_trans_handle *)current->journal_info;
4715 block_rsv = &root->fs_info->delalloc_block_rsv;
4716 space_info = block_rsv->space_info;
4717
4718 delalloc_bytes = percpu_counter_sum_positive(
4719 &root->fs_info->delalloc_bytes);
4720 if (delalloc_bytes == 0) {
4721 if (trans)
4722 return;
4723 if (wait_ordered)
4724 btrfs_wait_ordered_roots(root->fs_info, items,
4725 0, (u64)-1);
4726 return;
4727 }
4728
4729 loops = 0;
4730 while (delalloc_bytes && loops < 3) {
4731 max_reclaim = min(delalloc_bytes, to_reclaim);
4732 nr_pages = max_reclaim >> PAGE_SHIFT;
4733 btrfs_writeback_inodes_sb_nr(root, nr_pages, items);
4734 /*
4735 * We need to wait for the async pages to actually start before
4736 * we do anything.
4737 */
4738 max_reclaim = atomic_read(&root->fs_info->async_delalloc_pages);
4739 if (!max_reclaim)
4740 goto skip_async;
4741
4742 if (max_reclaim <= nr_pages)
4743 max_reclaim = 0;
4744 else
4745 max_reclaim -= nr_pages;
4746
4747 wait_event(root->fs_info->async_submit_wait,
4748 atomic_read(&root->fs_info->async_delalloc_pages) <=
4749 (int)max_reclaim);
4750 skip_async:
4751 if (!trans)
4752 flush = BTRFS_RESERVE_FLUSH_ALL;
4753 else
4754 flush = BTRFS_RESERVE_NO_FLUSH;
4755 spin_lock(&space_info->lock);
4756 if (can_overcommit(root, space_info, orig, flush)) {
4757 spin_unlock(&space_info->lock);
4758 break;
4759 }
4760 if (list_empty(&space_info->tickets) &&
4761 list_empty(&space_info->priority_tickets)) {
4762 spin_unlock(&space_info->lock);
4763 break;
4764 }
4765 spin_unlock(&space_info->lock);
4766
4767 loops++;
4768 if (wait_ordered && !trans) {
4769 btrfs_wait_ordered_roots(root->fs_info, items,
4770 0, (u64)-1);
4771 } else {
4772 time_left = schedule_timeout_killable(1);
4773 if (time_left)
4774 break;
4775 }
4776 delalloc_bytes = percpu_counter_sum_positive(
4777 &root->fs_info->delalloc_bytes);
4778 }
4779 }
4780
4781 /**
4782 * maybe_commit_transaction - possibly commit the transaction if its ok to
4783 * @root - the root we're allocating for
4784 * @bytes - the number of bytes we want to reserve
4785 * @force - force the commit
4786 *
4787 * This will check to make sure that committing the transaction will actually
4788 * get us somewhere and then commit the transaction if it does. Otherwise it
4789 * will return -ENOSPC.
4790 */
4791 static int may_commit_transaction(struct btrfs_root *root,
4792 struct btrfs_space_info *space_info,
4793 u64 bytes, int force)
4794 {
4795 struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
4796 struct btrfs_trans_handle *trans;
4797
4798 trans = (struct btrfs_trans_handle *)current->journal_info;
4799 if (trans)
4800 return -EAGAIN;
4801
4802 if (force)
4803 goto commit;
4804
4805 /* See if there is enough pinned space to make this reservation */
4806 if (percpu_counter_compare(&space_info->total_bytes_pinned,
4807 bytes) >= 0)
4808 goto commit;
4809
4810 /*
4811 * See if there is some space in the delayed insertion reservation for
4812 * this reservation.
4813 */
4814 if (space_info != delayed_rsv->space_info)
4815 return -ENOSPC;
4816
4817 spin_lock(&delayed_rsv->lock);
4818 if (percpu_counter_compare(&space_info->total_bytes_pinned,
4819 bytes - delayed_rsv->size) >= 0) {
4820 spin_unlock(&delayed_rsv->lock);
4821 return -ENOSPC;
4822 }
4823 spin_unlock(&delayed_rsv->lock);
4824
4825 commit:
4826 trans = btrfs_join_transaction(root);
4827 if (IS_ERR(trans))
4828 return -ENOSPC;
4829
4830 return btrfs_commit_transaction(trans, root);
4831 }
4832
4833 struct reserve_ticket {
4834 u64 bytes;
4835 int error;
4836 struct list_head list;
4837 wait_queue_head_t wait;
4838 };
4839
4840 static int flush_space(struct btrfs_root *root,
4841 struct btrfs_space_info *space_info, u64 num_bytes,
4842 u64 orig_bytes, int state)
4843 {
4844 struct btrfs_trans_handle *trans;
4845 int nr;
4846 int ret = 0;
4847
4848 switch (state) {
4849 case FLUSH_DELAYED_ITEMS_NR:
4850 case FLUSH_DELAYED_ITEMS:
4851 if (state == FLUSH_DELAYED_ITEMS_NR)
4852 nr = calc_reclaim_items_nr(root, num_bytes) * 2;
4853 else
4854 nr = -1;
4855
4856 trans = btrfs_join_transaction(root);
4857 if (IS_ERR(trans)) {
4858 ret = PTR_ERR(trans);
4859 break;
4860 }
4861 ret = btrfs_run_delayed_items_nr(trans, root, nr);
4862 btrfs_end_transaction(trans, root);
4863 break;
4864 case FLUSH_DELALLOC:
4865 case FLUSH_DELALLOC_WAIT:
4866 shrink_delalloc(root, num_bytes * 2, orig_bytes,
4867 state == FLUSH_DELALLOC_WAIT);
4868 break;
4869 case ALLOC_CHUNK:
4870 trans = btrfs_join_transaction(root);
4871 if (IS_ERR(trans)) {
4872 ret = PTR_ERR(trans);
4873 break;
4874 }
4875 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4876 btrfs_get_alloc_profile(root, 0),
4877 CHUNK_ALLOC_NO_FORCE);
4878 btrfs_end_transaction(trans, root);
4879 if (ret > 0 || ret == -ENOSPC)
4880 ret = 0;
4881 break;
4882 case COMMIT_TRANS:
4883 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
4884 break;
4885 default:
4886 ret = -ENOSPC;
4887 break;
4888 }
4889
4890 trace_btrfs_flush_space(root->fs_info, space_info->flags, num_bytes,
4891 orig_bytes, state, ret);
4892 return ret;
4893 }
4894
4895 static inline u64
4896 btrfs_calc_reclaim_metadata_size(struct btrfs_root *root,
4897 struct btrfs_space_info *space_info)
4898 {
4899 struct reserve_ticket *ticket;
4900 u64 used;
4901 u64 expected;
4902 u64 to_reclaim = 0;
4903
4904 list_for_each_entry(ticket, &space_info->tickets, list)
4905 to_reclaim += ticket->bytes;
4906 list_for_each_entry(ticket, &space_info->priority_tickets, list)
4907 to_reclaim += ticket->bytes;
4908 if (to_reclaim)
4909 return to_reclaim;
4910
4911 to_reclaim = min_t(u64, num_online_cpus() * SZ_1M, SZ_16M);
4912 if (can_overcommit(root, space_info, to_reclaim,
4913 BTRFS_RESERVE_FLUSH_ALL))
4914 return 0;
4915
4916 used = space_info->bytes_used + space_info->bytes_reserved +
4917 space_info->bytes_pinned + space_info->bytes_readonly +
4918 space_info->bytes_may_use;
4919 if (can_overcommit(root, space_info, SZ_1M, BTRFS_RESERVE_FLUSH_ALL))
4920 expected = div_factor_fine(space_info->total_bytes, 95);
4921 else
4922 expected = div_factor_fine(space_info->total_bytes, 90);
4923
4924 if (used > expected)
4925 to_reclaim = used - expected;
4926 else
4927 to_reclaim = 0;
4928 to_reclaim = min(to_reclaim, space_info->bytes_may_use +
4929 space_info->bytes_reserved);
4930 return to_reclaim;
4931 }
4932
4933 static inline int need_do_async_reclaim(struct btrfs_space_info *space_info,
4934 struct btrfs_root *root, u64 used)
4935 {
4936 u64 thresh = div_factor_fine(space_info->total_bytes, 98);
4937
4938 /* If we're just plain full then async reclaim just slows us down. */
4939 if ((space_info->bytes_used + space_info->bytes_reserved) >= thresh)
4940 return 0;
4941
4942 if (!btrfs_calc_reclaim_metadata_size(root, space_info))
4943 return 0;
4944
4945 return (used >= thresh && !btrfs_fs_closing(root->fs_info) &&
4946 !test_bit(BTRFS_FS_STATE_REMOUNTING,
4947 &root->fs_info->fs_state));
4948 }
4949
4950 static void wake_all_tickets(struct list_head *head)
4951 {
4952 struct reserve_ticket *ticket;
4953
4954 while (!list_empty(head)) {
4955 ticket = list_first_entry(head, struct reserve_ticket, list);
4956 list_del_init(&ticket->list);
4957 ticket->error = -ENOSPC;
4958 wake_up(&ticket->wait);
4959 }
4960 }
4961
4962 /*
4963 * This is for normal flushers, we can wait all goddamned day if we want to. We
4964 * will loop and continuously try to flush as long as we are making progress.
4965 * We count progress as clearing off tickets each time we have to loop.
4966 */
4967 static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
4968 {
4969 struct btrfs_fs_info *fs_info;
4970 struct btrfs_space_info *space_info;
4971 u64 to_reclaim;
4972 int flush_state;
4973 int commit_cycles = 0;
4974 u64 last_tickets_id;
4975
4976 fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
4977 space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4978
4979 spin_lock(&space_info->lock);
4980 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
4981 space_info);
4982 if (!to_reclaim) {
4983 space_info->flush = 0;
4984 spin_unlock(&space_info->lock);
4985 return;
4986 }
4987 last_tickets_id = space_info->tickets_id;
4988 spin_unlock(&space_info->lock);
4989
4990 flush_state = FLUSH_DELAYED_ITEMS_NR;
4991 do {
4992 struct reserve_ticket *ticket;
4993 int ret;
4994
4995 ret = flush_space(fs_info->fs_root, space_info, to_reclaim,
4996 to_reclaim, flush_state);
4997 spin_lock(&space_info->lock);
4998 if (list_empty(&space_info->tickets)) {
4999 space_info->flush = 0;
5000 spin_unlock(&space_info->lock);
5001 return;
5002 }
5003 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
5004 space_info);
5005 ticket = list_first_entry(&space_info->tickets,
5006 struct reserve_ticket, list);
5007 if (last_tickets_id == space_info->tickets_id) {
5008 flush_state++;
5009 } else {
5010 last_tickets_id = space_info->tickets_id;
5011 flush_state = FLUSH_DELAYED_ITEMS_NR;
5012 if (commit_cycles)
5013 commit_cycles--;
5014 }
5015
5016 if (flush_state > COMMIT_TRANS) {
5017 commit_cycles++;
5018 if (commit_cycles > 2) {
5019 wake_all_tickets(&space_info->tickets);
5020 space_info->flush = 0;
5021 } else {
5022 flush_state = FLUSH_DELAYED_ITEMS_NR;
5023 }
5024 }
5025 spin_unlock(&space_info->lock);
5026 } while (flush_state <= COMMIT_TRANS);
5027 }
5028
5029 void btrfs_init_async_reclaim_work(struct work_struct *work)
5030 {
5031 INIT_WORK(work, btrfs_async_reclaim_metadata_space);
5032 }
5033
5034 static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
5035 struct btrfs_space_info *space_info,
5036 struct reserve_ticket *ticket)
5037 {
5038 u64 to_reclaim;
5039 int flush_state = FLUSH_DELAYED_ITEMS_NR;
5040
5041 spin_lock(&space_info->lock);
5042 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
5043 space_info);
5044 if (!to_reclaim) {
5045 spin_unlock(&space_info->lock);
5046 return;
5047 }
5048 spin_unlock(&space_info->lock);
5049
5050 do {
5051 flush_space(fs_info->fs_root, space_info, to_reclaim,
5052 to_reclaim, flush_state);
5053 flush_state++;
5054 spin_lock(&space_info->lock);
5055 if (ticket->bytes == 0) {
5056 spin_unlock(&space_info->lock);
5057 return;
5058 }
5059 spin_unlock(&space_info->lock);
5060
5061 /*
5062 * Priority flushers can't wait on delalloc without
5063 * deadlocking.
5064 */
5065 if (flush_state == FLUSH_DELALLOC ||
5066 flush_state == FLUSH_DELALLOC_WAIT)
5067 flush_state = ALLOC_CHUNK;
5068 } while (flush_state < COMMIT_TRANS);
5069 }
5070
5071 static int wait_reserve_ticket(struct btrfs_fs_info *fs_info,
5072 struct btrfs_space_info *space_info,
5073 struct reserve_ticket *ticket, u64 orig_bytes)
5074
5075 {
5076 DEFINE_WAIT(wait);
5077 int ret = 0;
5078
5079 spin_lock(&space_info->lock);
5080 while (ticket->bytes > 0 && ticket->error == 0) {
5081 ret = prepare_to_wait_event(&ticket->wait, &wait, TASK_KILLABLE);
5082 if (ret) {
5083 ret = -EINTR;
5084 break;
5085 }
5086 spin_unlock(&space_info->lock);
5087
5088 schedule();
5089
5090 finish_wait(&ticket->wait, &wait);
5091 spin_lock(&space_info->lock);
5092 }
5093 if (!ret)
5094 ret = ticket->error;
5095 if (!list_empty(&ticket->list))
5096 list_del_init(&ticket->list);
5097 if (ticket->bytes && ticket->bytes < orig_bytes) {
5098 u64 num_bytes = orig_bytes - ticket->bytes;
5099 space_info->bytes_may_use -= num_bytes;
5100 trace_btrfs_space_reservation(fs_info, "space_info",
5101 space_info->flags, num_bytes, 0);
5102 }
5103 spin_unlock(&space_info->lock);
5104
5105 return ret;
5106 }
5107
5108 /**
5109 * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5110 * @root - the root we're allocating for
5111 * @space_info - the space info we want to allocate from
5112 * @orig_bytes - the number of bytes we want
5113 * @flush - whether or not we can flush to make our reservation
5114 *
5115 * This will reserve orig_bytes number of bytes from the space info associated
5116 * with the block_rsv. If there is not enough space it will make an attempt to
5117 * flush out space to make room. It will do this by flushing delalloc if
5118 * possible or committing the transaction. If flush is 0 then no attempts to
5119 * regain reservations will be made and this will fail if there is not enough
5120 * space already.
5121 */
5122 static int __reserve_metadata_bytes(struct btrfs_root *root,
5123 struct btrfs_space_info *space_info,
5124 u64 orig_bytes,
5125 enum btrfs_reserve_flush_enum flush)
5126 {
5127 struct reserve_ticket ticket;
5128 u64 used;
5129 int ret = 0;
5130
5131 ASSERT(orig_bytes);
5132 ASSERT(!current->journal_info || flush != BTRFS_RESERVE_FLUSH_ALL);
5133
5134 spin_lock(&space_info->lock);
5135 ret = -ENOSPC;
5136 used = space_info->bytes_used + space_info->bytes_reserved +
5137 space_info->bytes_pinned + space_info->bytes_readonly +
5138 space_info->bytes_may_use;
5139
5140 /*
5141 * If we have enough space then hooray, make our reservation and carry
5142 * on. If not see if we can overcommit, and if we can, hooray carry on.
5143 * If not things get more complicated.
5144 */
5145 if (used + orig_bytes <= space_info->total_bytes) {
5146 space_info->bytes_may_use += orig_bytes;
5147 trace_btrfs_space_reservation(root->fs_info, "space_info",
5148 space_info->flags, orig_bytes,
5149 1);
5150 ret = 0;
5151 } else if (can_overcommit(root, space_info, orig_bytes, flush)) {
5152 space_info->bytes_may_use += orig_bytes;
5153 trace_btrfs_space_reservation(root->fs_info, "space_info",
5154 space_info->flags, orig_bytes,
5155 1);
5156 ret = 0;
5157 }
5158
5159 /*
5160 * If we couldn't make a reservation then setup our reservation ticket
5161 * and kick the async worker if it's not already running.
5162 *
5163 * If we are a priority flusher then we just need to add our ticket to
5164 * the list and we will do our own flushing further down.
5165 */
5166 if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
5167 ticket.bytes = orig_bytes;
5168 ticket.error = 0;
5169 init_waitqueue_head(&ticket.wait);
5170 if (flush == BTRFS_RESERVE_FLUSH_ALL) {
5171 list_add_tail(&ticket.list, &space_info->tickets);
5172 if (!space_info->flush) {
5173 space_info->flush = 1;
5174 trace_btrfs_trigger_flush(root->fs_info,
5175 space_info->flags,
5176 orig_bytes, flush,
5177 "enospc");
5178 queue_work(system_unbound_wq,
5179 &root->fs_info->async_reclaim_work);
5180 }
5181 } else {
5182 list_add_tail(&ticket.list,
5183 &space_info->priority_tickets);
5184 }
5185 } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
5186 used += orig_bytes;
5187 /*
5188 * We will do the space reservation dance during log replay,
5189 * which means we won't have fs_info->fs_root set, so don't do
5190 * the async reclaim as we will panic.
5191 */
5192 if (!root->fs_info->log_root_recovering &&
5193 need_do_async_reclaim(space_info, root, used) &&
5194 !work_busy(&root->fs_info->async_reclaim_work)) {
5195 trace_btrfs_trigger_flush(root->fs_info,
5196 space_info->flags,
5197 orig_bytes, flush,
5198 "preempt");
5199 queue_work(system_unbound_wq,
5200 &root->fs_info->async_reclaim_work);
5201 }
5202 }
5203 spin_unlock(&space_info->lock);
5204 if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
5205 return ret;
5206
5207 if (flush == BTRFS_RESERVE_FLUSH_ALL)
5208 return wait_reserve_ticket(root->fs_info, space_info, &ticket,
5209 orig_bytes);
5210
5211 ret = 0;
5212 priority_reclaim_metadata_space(root->fs_info, space_info, &ticket);
5213 spin_lock(&space_info->lock);
5214 if (ticket.bytes) {
5215 if (ticket.bytes < orig_bytes) {
5216 u64 num_bytes = orig_bytes - ticket.bytes;
5217 space_info->bytes_may_use -= num_bytes;
5218 trace_btrfs_space_reservation(root->fs_info,
5219 "space_info", space_info->flags,
5220 num_bytes, 0);
5221
5222 }
5223 list_del_init(&ticket.list);
5224 ret = -ENOSPC;
5225 }
5226 spin_unlock(&space_info->lock);
5227 ASSERT(list_empty(&ticket.list));
5228 return ret;
5229 }
5230
5231 /**
5232 * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5233 * @root - the root we're allocating for
5234 * @block_rsv - the block_rsv we're allocating for
5235 * @orig_bytes - the number of bytes we want
5236 * @flush - whether or not we can flush to make our reservation
5237 *
5238 * This will reserve orgi_bytes number of bytes from the space info associated
5239 * with the block_rsv. If there is not enough space it will make an attempt to
5240 * flush out space to make room. It will do this by flushing delalloc if
5241 * possible or committing the transaction. If flush is 0 then no attempts to
5242 * regain reservations will be made and this will fail if there is not enough
5243 * space already.
5244 */
5245 static int reserve_metadata_bytes(struct btrfs_root *root,
5246 struct btrfs_block_rsv *block_rsv,
5247 u64 orig_bytes,
5248 enum btrfs_reserve_flush_enum flush)
5249 {
5250 int ret;
5251
5252 ret = __reserve_metadata_bytes(root, block_rsv->space_info, orig_bytes,
5253 flush);
5254 if (ret == -ENOSPC &&
5255 unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
5256 struct btrfs_block_rsv *global_rsv =
5257 &root->fs_info->global_block_rsv;
5258
5259 if (block_rsv != global_rsv &&
5260 !block_rsv_use_bytes(global_rsv, orig_bytes))
5261 ret = 0;
5262 }
5263 if (ret == -ENOSPC)
5264 trace_btrfs_space_reservation(root->fs_info,
5265 "space_info:enospc",
5266 block_rsv->space_info->flags,
5267 orig_bytes, 1);
5268 return ret;
5269 }
5270
5271 static struct btrfs_block_rsv *get_block_rsv(
5272 const struct btrfs_trans_handle *trans,
5273 const struct btrfs_root *root)
5274 {
5275 struct btrfs_block_rsv *block_rsv = NULL;
5276
5277 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
5278 (root == root->fs_info->csum_root && trans->adding_csums) ||
5279 (root == root->fs_info->uuid_root))
5280 block_rsv = trans->block_rsv;
5281
5282 if (!block_rsv)
5283 block_rsv = root->block_rsv;
5284
5285 if (!block_rsv)
5286 block_rsv = &root->fs_info->empty_block_rsv;
5287
5288 return block_rsv;
5289 }
5290
5291 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
5292 u64 num_bytes)
5293 {
5294 int ret = -ENOSPC;
5295 spin_lock(&block_rsv->lock);
5296 if (block_rsv->reserved >= num_bytes) {
5297 block_rsv->reserved -= num_bytes;
5298 if (block_rsv->reserved < block_rsv->size)
5299 block_rsv->full = 0;
5300 ret = 0;
5301 }
5302 spin_unlock(&block_rsv->lock);
5303 return ret;
5304 }
5305
5306 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
5307 u64 num_bytes, int update_size)
5308 {
5309 spin_lock(&block_rsv->lock);
5310 block_rsv->reserved += num_bytes;
5311 if (update_size)
5312 block_rsv->size += num_bytes;
5313 else if (block_rsv->reserved >= block_rsv->size)
5314 block_rsv->full = 1;
5315 spin_unlock(&block_rsv->lock);
5316 }
5317
5318 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
5319 struct btrfs_block_rsv *dest, u64 num_bytes,
5320 int min_factor)
5321 {
5322 struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5323 u64 min_bytes;
5324
5325 if (global_rsv->space_info != dest->space_info)
5326 return -ENOSPC;
5327
5328 spin_lock(&global_rsv->lock);
5329 min_bytes = div_factor(global_rsv->size, min_factor);
5330 if (global_rsv->reserved < min_bytes + num_bytes) {
5331 spin_unlock(&global_rsv->lock);
5332 return -ENOSPC;
5333 }
5334 global_rsv->reserved -= num_bytes;
5335 if (global_rsv->reserved < global_rsv->size)
5336 global_rsv->full = 0;
5337 spin_unlock(&global_rsv->lock);
5338
5339 block_rsv_add_bytes(dest, num_bytes, 1);
5340 return 0;
5341 }
5342
5343 /*
5344 * This is for space we already have accounted in space_info->bytes_may_use, so
5345 * basically when we're returning space from block_rsv's.
5346 */
5347 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
5348 struct btrfs_space_info *space_info,
5349 u64 num_bytes)
5350 {
5351 struct reserve_ticket *ticket;
5352 struct list_head *head;
5353 u64 used;
5354 enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_NO_FLUSH;
5355 bool check_overcommit = false;
5356
5357 spin_lock(&space_info->lock);
5358 head = &space_info->priority_tickets;
5359
5360 /*
5361 * If we are over our limit then we need to check and see if we can
5362 * overcommit, and if we can't then we just need to free up our space
5363 * and not satisfy any requests.
5364 */
5365 used = space_info->bytes_used + space_info->bytes_reserved +
5366 space_info->bytes_pinned + space_info->bytes_readonly +
5367 space_info->bytes_may_use;
5368 if (used - num_bytes >= space_info->total_bytes)
5369 check_overcommit = true;
5370 again:
5371 while (!list_empty(head) && num_bytes) {
5372 ticket = list_first_entry(head, struct reserve_ticket,
5373 list);
5374 /*
5375 * We use 0 bytes because this space is already reserved, so
5376 * adding the ticket space would be a double count.
5377 */
5378 if (check_overcommit &&
5379 !can_overcommit(fs_info->extent_root, space_info, 0,
5380 flush))
5381 break;
5382 if (num_bytes >= ticket->bytes) {
5383 list_del_init(&ticket->list);
5384 num_bytes -= ticket->bytes;
5385 ticket->bytes = 0;
5386 space_info->tickets_id++;
5387 wake_up(&ticket->wait);
5388 } else {
5389 ticket->bytes -= num_bytes;
5390 num_bytes = 0;
5391 }
5392 }
5393
5394 if (num_bytes && head == &space_info->priority_tickets) {
5395 head = &space_info->tickets;
5396 flush = BTRFS_RESERVE_FLUSH_ALL;
5397 goto again;
5398 }
5399 space_info->bytes_may_use -= num_bytes;
5400 trace_btrfs_space_reservation(fs_info, "space_info",
5401 space_info->flags, num_bytes, 0);
5402 spin_unlock(&space_info->lock);
5403 }
5404
5405 /*
5406 * This is for newly allocated space that isn't accounted in
5407 * space_info->bytes_may_use yet. So if we allocate a chunk or unpin an extent
5408 * we use this helper.
5409 */
5410 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
5411 struct btrfs_space_info *space_info,
5412 u64 num_bytes)
5413 {
5414 struct reserve_ticket *ticket;
5415 struct list_head *head = &space_info->priority_tickets;
5416
5417 again:
5418 while (!list_empty(head) && num_bytes) {
5419 ticket = list_first_entry(head, struct reserve_ticket,
5420 list);
5421 if (num_bytes >= ticket->bytes) {
5422 trace_btrfs_space_reservation(fs_info, "space_info",
5423 space_info->flags,
5424 ticket->bytes, 1);
5425 list_del_init(&ticket->list);
5426 num_bytes -= ticket->bytes;
5427 space_info->bytes_may_use += ticket->bytes;
5428 ticket->bytes = 0;
5429 space_info->tickets_id++;
5430 wake_up(&ticket->wait);
5431 } else {
5432 trace_btrfs_space_reservation(fs_info, "space_info",
5433 space_info->flags,
5434 num_bytes, 1);
5435 space_info->bytes_may_use += num_bytes;
5436 ticket->bytes -= num_bytes;
5437 num_bytes = 0;
5438 }
5439 }
5440
5441 if (num_bytes && head == &space_info->priority_tickets) {
5442 head = &space_info->tickets;
5443 goto again;
5444 }
5445 }
5446
5447 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
5448 struct btrfs_block_rsv *block_rsv,
5449 struct btrfs_block_rsv *dest, u64 num_bytes)
5450 {
5451 struct btrfs_space_info *space_info = block_rsv->space_info;
5452
5453 spin_lock(&block_rsv->lock);
5454 if (num_bytes == (u64)-1)
5455 num_bytes = block_rsv->size;
5456 block_rsv->size -= num_bytes;
5457 if (block_rsv->reserved >= block_rsv->size) {
5458 num_bytes = block_rsv->reserved - block_rsv->size;
5459 block_rsv->reserved = block_rsv->size;
5460 block_rsv->full = 1;
5461 } else {
5462 num_bytes = 0;
5463 }
5464 spin_unlock(&block_rsv->lock);
5465
5466 if (num_bytes > 0) {
5467 if (dest) {
5468 spin_lock(&dest->lock);
5469 if (!dest->full) {
5470 u64 bytes_to_add;
5471
5472 bytes_to_add = dest->size - dest->reserved;
5473 bytes_to_add = min(num_bytes, bytes_to_add);
5474 dest->reserved += bytes_to_add;
5475 if (dest->reserved >= dest->size)
5476 dest->full = 1;
5477 num_bytes -= bytes_to_add;
5478 }
5479 spin_unlock(&dest->lock);
5480 }
5481 if (num_bytes)
5482 space_info_add_old_bytes(fs_info, space_info,
5483 num_bytes);
5484 }
5485 }
5486
5487 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src,
5488 struct btrfs_block_rsv *dst, u64 num_bytes,
5489 int update_size)
5490 {
5491 int ret;
5492
5493 ret = block_rsv_use_bytes(src, num_bytes);
5494 if (ret)
5495 return ret;
5496
5497 block_rsv_add_bytes(dst, num_bytes, update_size);
5498 return 0;
5499 }
5500
5501 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
5502 {
5503 memset(rsv, 0, sizeof(*rsv));
5504 spin_lock_init(&rsv->lock);
5505 rsv->type = type;
5506 }
5507
5508 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
5509 unsigned short type)
5510 {
5511 struct btrfs_block_rsv *block_rsv;
5512 struct btrfs_fs_info *fs_info = root->fs_info;
5513
5514 block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
5515 if (!block_rsv)
5516 return NULL;
5517
5518 btrfs_init_block_rsv(block_rsv, type);
5519 block_rsv->space_info = __find_space_info(fs_info,
5520 BTRFS_BLOCK_GROUP_METADATA);
5521 return block_rsv;
5522 }
5523
5524 void btrfs_free_block_rsv(struct btrfs_root *root,
5525 struct btrfs_block_rsv *rsv)
5526 {
5527 if (!rsv)
5528 return;
5529 btrfs_block_rsv_release(root, rsv, (u64)-1);
5530 kfree(rsv);
5531 }
5532
5533 void __btrfs_free_block_rsv(struct btrfs_block_rsv *rsv)
5534 {
5535 kfree(rsv);
5536 }
5537
5538 int btrfs_block_rsv_add(struct btrfs_root *root,
5539 struct btrfs_block_rsv *block_rsv, u64 num_bytes,
5540 enum btrfs_reserve_flush_enum flush)
5541 {
5542 int ret;
5543
5544 if (num_bytes == 0)
5545 return 0;
5546
5547 ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5548 if (!ret) {
5549 block_rsv_add_bytes(block_rsv, num_bytes, 1);
5550 return 0;
5551 }
5552
5553 return ret;
5554 }
5555
5556 int btrfs_block_rsv_check(struct btrfs_root *root,
5557 struct btrfs_block_rsv *block_rsv, int min_factor)
5558 {
5559 u64 num_bytes = 0;
5560 int ret = -ENOSPC;
5561
5562 if (!block_rsv)
5563 return 0;
5564
5565 spin_lock(&block_rsv->lock);
5566 num_bytes = div_factor(block_rsv->size, min_factor);
5567 if (block_rsv->reserved >= num_bytes)
5568 ret = 0;
5569 spin_unlock(&block_rsv->lock);
5570
5571 return ret;
5572 }
5573
5574 int btrfs_block_rsv_refill(struct btrfs_root *root,
5575 struct btrfs_block_rsv *block_rsv, u64 min_reserved,
5576 enum btrfs_reserve_flush_enum flush)
5577 {
5578 u64 num_bytes = 0;
5579 int ret = -ENOSPC;
5580
5581 if (!block_rsv)
5582 return 0;
5583
5584 spin_lock(&block_rsv->lock);
5585 num_bytes = min_reserved;
5586 if (block_rsv->reserved >= num_bytes)
5587 ret = 0;
5588 else
5589 num_bytes -= block_rsv->reserved;
5590 spin_unlock(&block_rsv->lock);
5591
5592 if (!ret)
5593 return 0;
5594
5595 ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5596 if (!ret) {
5597 block_rsv_add_bytes(block_rsv, num_bytes, 0);
5598 return 0;
5599 }
5600
5601 return ret;
5602 }
5603
5604 void btrfs_block_rsv_release(struct btrfs_root *root,
5605 struct btrfs_block_rsv *block_rsv,
5606 u64 num_bytes)
5607 {
5608 struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5609 if (global_rsv == block_rsv ||
5610 block_rsv->space_info != global_rsv->space_info)
5611 global_rsv = NULL;
5612 block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
5613 num_bytes);
5614 }
5615
5616 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
5617 {
5618 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
5619 struct btrfs_space_info *sinfo = block_rsv->space_info;
5620 u64 num_bytes;
5621
5622 /*
5623 * The global block rsv is based on the size of the extent tree, the
5624 * checksum tree and the root tree. If the fs is empty we want to set
5625 * it to a minimal amount for safety.
5626 */
5627 num_bytes = btrfs_root_used(&fs_info->extent_root->root_item) +
5628 btrfs_root_used(&fs_info->csum_root->root_item) +
5629 btrfs_root_used(&fs_info->tree_root->root_item);
5630 num_bytes = max_t(u64, num_bytes, SZ_16M);
5631
5632 spin_lock(&sinfo->lock);
5633 spin_lock(&block_rsv->lock);
5634
5635 block_rsv->size = min_t(u64, num_bytes, SZ_512M);
5636
5637 if (block_rsv->reserved < block_rsv->size) {
5638 num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
5639 sinfo->bytes_reserved + sinfo->bytes_readonly +
5640 sinfo->bytes_may_use;
5641 if (sinfo->total_bytes > num_bytes) {
5642 num_bytes = sinfo->total_bytes - num_bytes;
5643 num_bytes = min(num_bytes,
5644 block_rsv->size - block_rsv->reserved);
5645 block_rsv->reserved += num_bytes;
5646 sinfo->bytes_may_use += num_bytes;
5647 trace_btrfs_space_reservation(fs_info, "space_info",
5648 sinfo->flags, num_bytes,
5649 1);
5650 }
5651 } else if (block_rsv->reserved > block_rsv->size) {
5652 num_bytes = block_rsv->reserved - block_rsv->size;
5653 sinfo->bytes_may_use -= num_bytes;
5654 trace_btrfs_space_reservation(fs_info, "space_info",
5655 sinfo->flags, num_bytes, 0);
5656 block_rsv->reserved = block_rsv->size;
5657 }
5658
5659 if (block_rsv->reserved == block_rsv->size)
5660 block_rsv->full = 1;
5661 else
5662 block_rsv->full = 0;
5663
5664 spin_unlock(&block_rsv->lock);
5665 spin_unlock(&sinfo->lock);
5666 }
5667
5668 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
5669 {
5670 struct btrfs_space_info *space_info;
5671
5672 space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
5673 fs_info->chunk_block_rsv.space_info = space_info;
5674
5675 space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5676 fs_info->global_block_rsv.space_info = space_info;
5677 fs_info->delalloc_block_rsv.space_info = space_info;
5678 fs_info->trans_block_rsv.space_info = space_info;
5679 fs_info->empty_block_rsv.space_info = space_info;
5680 fs_info->delayed_block_rsv.space_info = space_info;
5681
5682 fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
5683 fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
5684 fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
5685 fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
5686 if (fs_info->quota_root)
5687 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
5688 fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
5689
5690 update_global_block_rsv(fs_info);
5691 }
5692
5693 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
5694 {
5695 block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
5696 (u64)-1);
5697 WARN_ON(fs_info->delalloc_block_rsv.size > 0);
5698 WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
5699 WARN_ON(fs_info->trans_block_rsv.size > 0);
5700 WARN_ON(fs_info->trans_block_rsv.reserved > 0);
5701 WARN_ON(fs_info->chunk_block_rsv.size > 0);
5702 WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
5703 WARN_ON(fs_info->delayed_block_rsv.size > 0);
5704 WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
5705 }
5706
5707 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
5708 struct btrfs_root *root)
5709 {
5710 if (!trans->block_rsv)
5711 return;
5712
5713 if (!trans->bytes_reserved)
5714 return;
5715
5716 trace_btrfs_space_reservation(root->fs_info, "transaction",
5717 trans->transid, trans->bytes_reserved, 0);
5718 btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
5719 trans->bytes_reserved = 0;
5720 }
5721
5722 /*
5723 * To be called after all the new block groups attached to the transaction
5724 * handle have been created (btrfs_create_pending_block_groups()).
5725 */
5726 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
5727 {
5728 struct btrfs_fs_info *fs_info = trans->fs_info;
5729
5730 if (!trans->chunk_bytes_reserved)
5731 return;
5732
5733 WARN_ON_ONCE(!list_empty(&trans->new_bgs));
5734
5735 block_rsv_release_bytes(fs_info, &fs_info->chunk_block_rsv, NULL,
5736 trans->chunk_bytes_reserved);
5737 trans->chunk_bytes_reserved = 0;
5738 }
5739
5740 /* Can only return 0 or -ENOSPC */
5741 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
5742 struct inode *inode)
5743 {
5744 struct btrfs_root *root = BTRFS_I(inode)->root;
5745 /*
5746 * We always use trans->block_rsv here as we will have reserved space
5747 * for our orphan when starting the transaction, using get_block_rsv()
5748 * here will sometimes make us choose the wrong block rsv as we could be
5749 * doing a reloc inode for a non refcounted root.
5750 */
5751 struct btrfs_block_rsv *src_rsv = trans->block_rsv;
5752 struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
5753
5754 /*
5755 * We need to hold space in order to delete our orphan item once we've
5756 * added it, so this takes the reservation so we can release it later
5757 * when we are truly done with the orphan item.
5758 */
5759 u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5760 trace_btrfs_space_reservation(root->fs_info, "orphan",
5761 btrfs_ino(inode), num_bytes, 1);
5762 return btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes, 1);
5763 }
5764
5765 void btrfs_orphan_release_metadata(struct inode *inode)
5766 {
5767 struct btrfs_root *root = BTRFS_I(inode)->root;
5768 u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5769 trace_btrfs_space_reservation(root->fs_info, "orphan",
5770 btrfs_ino(inode), num_bytes, 0);
5771 btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
5772 }
5773
5774 /*
5775 * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
5776 * root: the root of the parent directory
5777 * rsv: block reservation
5778 * items: the number of items that we need do reservation
5779 * qgroup_reserved: used to return the reserved size in qgroup
5780 *
5781 * This function is used to reserve the space for snapshot/subvolume
5782 * creation and deletion. Those operations are different with the
5783 * common file/directory operations, they change two fs/file trees
5784 * and root tree, the number of items that the qgroup reserves is
5785 * different with the free space reservation. So we can not use
5786 * the space reservation mechanism in start_transaction().
5787 */
5788 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
5789 struct btrfs_block_rsv *rsv,
5790 int items,
5791 u64 *qgroup_reserved,
5792 bool use_global_rsv)
5793 {
5794 u64 num_bytes;
5795 int ret;
5796 struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5797
5798 if (root->fs_info->quota_enabled) {
5799 /* One for parent inode, two for dir entries */
5800 num_bytes = 3 * root->nodesize;
5801 ret = btrfs_qgroup_reserve_meta(root, num_bytes);
5802 if (ret)
5803 return ret;
5804 } else {
5805 num_bytes = 0;
5806 }
5807
5808 *qgroup_reserved = num_bytes;
5809
5810 num_bytes = btrfs_calc_trans_metadata_size(root, items);
5811 rsv->space_info = __find_space_info(root->fs_info,
5812 BTRFS_BLOCK_GROUP_METADATA);
5813 ret = btrfs_block_rsv_add(root, rsv, num_bytes,
5814 BTRFS_RESERVE_FLUSH_ALL);
5815
5816 if (ret == -ENOSPC && use_global_rsv)
5817 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes, 1);
5818
5819 if (ret && *qgroup_reserved)
5820 btrfs_qgroup_free_meta(root, *qgroup_reserved);
5821
5822 return ret;
5823 }
5824
5825 void btrfs_subvolume_release_metadata(struct btrfs_root *root,
5826 struct btrfs_block_rsv *rsv,
5827 u64 qgroup_reserved)
5828 {
5829 btrfs_block_rsv_release(root, rsv, (u64)-1);
5830 }
5831
5832 /**
5833 * drop_outstanding_extent - drop an outstanding extent
5834 * @inode: the inode we're dropping the extent for
5835 * @num_bytes: the number of bytes we're releasing.
5836 *
5837 * This is called when we are freeing up an outstanding extent, either called
5838 * after an error or after an extent is written. This will return the number of
5839 * reserved extents that need to be freed. This must be called with
5840 * BTRFS_I(inode)->lock held.
5841 */
5842 static unsigned drop_outstanding_extent(struct inode *inode, u64 num_bytes)
5843 {
5844 unsigned drop_inode_space = 0;
5845 unsigned dropped_extents = 0;
5846 unsigned num_extents = 0;
5847
5848 num_extents = (unsigned)div64_u64(num_bytes +
5849 BTRFS_MAX_EXTENT_SIZE - 1,
5850 BTRFS_MAX_EXTENT_SIZE);
5851 ASSERT(num_extents);
5852 ASSERT(BTRFS_I(inode)->outstanding_extents >= num_extents);
5853 BTRFS_I(inode)->outstanding_extents -= num_extents;
5854
5855 if (BTRFS_I(inode)->outstanding_extents == 0 &&
5856 test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5857 &BTRFS_I(inode)->runtime_flags))
5858 drop_inode_space = 1;
5859
5860 /*
5861 * If we have more or the same amount of outstanding extents than we have
5862 * reserved then we need to leave the reserved extents count alone.
5863 */
5864 if (BTRFS_I(inode)->outstanding_extents >=
5865 BTRFS_I(inode)->reserved_extents)
5866 return drop_inode_space;
5867
5868 dropped_extents = BTRFS_I(inode)->reserved_extents -
5869 BTRFS_I(inode)->outstanding_extents;
5870 BTRFS_I(inode)->reserved_extents -= dropped_extents;
5871 return dropped_extents + drop_inode_space;
5872 }
5873
5874 /**
5875 * calc_csum_metadata_size - return the amount of metadata space that must be
5876 * reserved/freed for the given bytes.
5877 * @inode: the inode we're manipulating
5878 * @num_bytes: the number of bytes in question
5879 * @reserve: 1 if we are reserving space, 0 if we are freeing space
5880 *
5881 * This adjusts the number of csum_bytes in the inode and then returns the
5882 * correct amount of metadata that must either be reserved or freed. We
5883 * calculate how many checksums we can fit into one leaf and then divide the
5884 * number of bytes that will need to be checksumed by this value to figure out
5885 * how many checksums will be required. If we are adding bytes then the number
5886 * may go up and we will return the number of additional bytes that must be
5887 * reserved. If it is going down we will return the number of bytes that must
5888 * be freed.
5889 *
5890 * This must be called with BTRFS_I(inode)->lock held.
5891 */
5892 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
5893 int reserve)
5894 {
5895 struct btrfs_root *root = BTRFS_I(inode)->root;
5896 u64 old_csums, num_csums;
5897
5898 if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
5899 BTRFS_I(inode)->csum_bytes == 0)
5900 return 0;
5901
5902 old_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5903 if (reserve)
5904 BTRFS_I(inode)->csum_bytes += num_bytes;
5905 else
5906 BTRFS_I(inode)->csum_bytes -= num_bytes;
5907 num_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5908
5909 /* No change, no need to reserve more */
5910 if (old_csums == num_csums)
5911 return 0;
5912
5913 if (reserve)
5914 return btrfs_calc_trans_metadata_size(root,
5915 num_csums - old_csums);
5916
5917 return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
5918 }
5919
5920 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
5921 {
5922 struct btrfs_root *root = BTRFS_I(inode)->root;
5923 struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
5924 u64 to_reserve = 0;
5925 u64 csum_bytes;
5926 unsigned nr_extents = 0;
5927 enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
5928 int ret = 0;
5929 bool delalloc_lock = true;
5930 u64 to_free = 0;
5931 unsigned dropped;
5932 bool release_extra = false;
5933
5934 /* If we are a free space inode we need to not flush since we will be in
5935 * the middle of a transaction commit. We also don't need the delalloc
5936 * mutex since we won't race with anybody. We need this mostly to make
5937 * lockdep shut its filthy mouth.
5938 *
5939 * If we have a transaction open (can happen if we call truncate_block
5940 * from truncate), then we need FLUSH_LIMIT so we don't deadlock.
5941 */
5942 if (btrfs_is_free_space_inode(inode)) {
5943 flush = BTRFS_RESERVE_NO_FLUSH;
5944 delalloc_lock = false;
5945 } else if (current->journal_info) {
5946 flush = BTRFS_RESERVE_FLUSH_LIMIT;
5947 }
5948
5949 if (flush != BTRFS_RESERVE_NO_FLUSH &&
5950 btrfs_transaction_in_commit(root->fs_info))
5951 schedule_timeout(1);
5952
5953 if (delalloc_lock)
5954 mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
5955
5956 num_bytes = ALIGN(num_bytes, root->sectorsize);
5957
5958 spin_lock(&BTRFS_I(inode)->lock);
5959 nr_extents = (unsigned)div64_u64(num_bytes +
5960 BTRFS_MAX_EXTENT_SIZE - 1,
5961 BTRFS_MAX_EXTENT_SIZE);
5962 BTRFS_I(inode)->outstanding_extents += nr_extents;
5963
5964 nr_extents = 0;
5965 if (BTRFS_I(inode)->outstanding_extents >
5966 BTRFS_I(inode)->reserved_extents)
5967 nr_extents += BTRFS_I(inode)->outstanding_extents -
5968 BTRFS_I(inode)->reserved_extents;
5969
5970 /* We always want to reserve a slot for updating the inode. */
5971 to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents + 1);
5972 to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
5973 csum_bytes = BTRFS_I(inode)->csum_bytes;
5974 spin_unlock(&BTRFS_I(inode)->lock);
5975
5976 if (root->fs_info->quota_enabled) {
5977 ret = btrfs_qgroup_reserve_meta(root,
5978 nr_extents * root->nodesize);
5979 if (ret)
5980 goto out_fail;
5981 }
5982
5983 ret = btrfs_block_rsv_add(root, block_rsv, to_reserve, flush);
5984 if (unlikely(ret)) {
5985 btrfs_qgroup_free_meta(root, nr_extents * root->nodesize);
5986 goto out_fail;
5987 }
5988
5989 spin_lock(&BTRFS_I(inode)->lock);
5990 if (test_and_set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5991 &BTRFS_I(inode)->runtime_flags)) {
5992 to_reserve -= btrfs_calc_trans_metadata_size(root, 1);
5993 release_extra = true;
5994 }
5995 BTRFS_I(inode)->reserved_extents += nr_extents;
5996 spin_unlock(&BTRFS_I(inode)->lock);
5997
5998 if (delalloc_lock)
5999 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
6000
6001 if (to_reserve)
6002 trace_btrfs_space_reservation(root->fs_info, "delalloc",
6003 btrfs_ino(inode), to_reserve, 1);
6004 if (release_extra)
6005 btrfs_block_rsv_release(root, block_rsv,
6006 btrfs_calc_trans_metadata_size(root,
6007 1));
6008 return 0;
6009
6010 out_fail:
6011 spin_lock(&BTRFS_I(inode)->lock);
6012 dropped = drop_outstanding_extent(inode, num_bytes);
6013 /*
6014 * If the inodes csum_bytes is the same as the original
6015 * csum_bytes then we know we haven't raced with any free()ers
6016 * so we can just reduce our inodes csum bytes and carry on.
6017 */
6018 if (BTRFS_I(inode)->csum_bytes == csum_bytes) {
6019 calc_csum_metadata_size(inode, num_bytes, 0);
6020 } else {
6021 u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes;
6022 u64 bytes;
6023
6024 /*
6025 * This is tricky, but first we need to figure out how much we
6026 * freed from any free-ers that occurred during this
6027 * reservation, so we reset ->csum_bytes to the csum_bytes
6028 * before we dropped our lock, and then call the free for the
6029 * number of bytes that were freed while we were trying our
6030 * reservation.
6031 */
6032 bytes = csum_bytes - BTRFS_I(inode)->csum_bytes;
6033 BTRFS_I(inode)->csum_bytes = csum_bytes;
6034 to_free = calc_csum_metadata_size(inode, bytes, 0);
6035
6036
6037 /*
6038 * Now we need to see how much we would have freed had we not
6039 * been making this reservation and our ->csum_bytes were not
6040 * artificially inflated.
6041 */
6042 BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes;
6043 bytes = csum_bytes - orig_csum_bytes;
6044 bytes = calc_csum_metadata_size(inode, bytes, 0);
6045
6046 /*
6047 * Now reset ->csum_bytes to what it should be. If bytes is
6048 * more than to_free then we would have freed more space had we
6049 * not had an artificially high ->csum_bytes, so we need to free
6050 * the remainder. If bytes is the same or less then we don't
6051 * need to do anything, the other free-ers did the correct
6052 * thing.
6053 */
6054 BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes;
6055 if (bytes > to_free)
6056 to_free = bytes - to_free;
6057 else
6058 to_free = 0;
6059 }
6060 spin_unlock(&BTRFS_I(inode)->lock);
6061 if (dropped)
6062 to_free += btrfs_calc_trans_metadata_size(root, dropped);
6063
6064 if (to_free) {
6065 btrfs_block_rsv_release(root, block_rsv, to_free);
6066 trace_btrfs_space_reservation(root->fs_info, "delalloc",
6067 btrfs_ino(inode), to_free, 0);
6068 }
6069 if (delalloc_lock)
6070 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
6071 return ret;
6072 }
6073
6074 /**
6075 * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
6076 * @inode: the inode to release the reservation for
6077 * @num_bytes: the number of bytes we're releasing
6078 *
6079 * This will release the metadata reservation for an inode. This can be called
6080 * once we complete IO for a given set of bytes to release their metadata
6081 * reservations.
6082 */
6083 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
6084 {
6085 struct btrfs_root *root = BTRFS_I(inode)->root;
6086 u64 to_free = 0;
6087 unsigned dropped;
6088
6089 num_bytes = ALIGN(num_bytes, root->sectorsize);
6090 spin_lock(&BTRFS_I(inode)->lock);
6091 dropped = drop_outstanding_extent(inode, num_bytes);
6092
6093 if (num_bytes)
6094 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
6095 spin_unlock(&BTRFS_I(inode)->lock);
6096 if (dropped > 0)
6097 to_free += btrfs_calc_trans_metadata_size(root, dropped);
6098
6099 if (btrfs_is_testing(root->fs_info))
6100 return;
6101
6102 trace_btrfs_space_reservation(root->fs_info, "delalloc",
6103 btrfs_ino(inode), to_free, 0);
6104
6105 btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
6106 to_free);
6107 }
6108
6109 /**
6110 * btrfs_delalloc_reserve_space - reserve data and metadata space for
6111 * delalloc
6112 * @inode: inode we're writing to
6113 * @start: start range we are writing to
6114 * @len: how long the range we are writing to
6115 *
6116 * TODO: This function will finally replace old btrfs_delalloc_reserve_space()
6117 *
6118 * This will do the following things
6119 *
6120 * o reserve space in data space info for num bytes
6121 * and reserve precious corresponding qgroup space
6122 * (Done in check_data_free_space)
6123 *
6124 * o reserve space for metadata space, based on the number of outstanding
6125 * extents and how much csums will be needed
6126 * also reserve metadata space in a per root over-reserve method.
6127 * o add to the inodes->delalloc_bytes
6128 * o add it to the fs_info's delalloc inodes list.
6129 * (Above 3 all done in delalloc_reserve_metadata)
6130 *
6131 * Return 0 for success
6132 * Return <0 for error(-ENOSPC or -EQUOT)
6133 */
6134 int btrfs_delalloc_reserve_space(struct inode *inode, u64 start, u64 len)
6135 {
6136 int ret;
6137
6138 ret = btrfs_check_data_free_space(inode, start, len);
6139 if (ret < 0)
6140 return ret;
6141 ret = btrfs_delalloc_reserve_metadata(inode, len);
6142 if (ret < 0)
6143 btrfs_free_reserved_data_space(inode, start, len);
6144 return ret;
6145 }
6146
6147 /**
6148 * btrfs_delalloc_release_space - release data and metadata space for delalloc
6149 * @inode: inode we're releasing space for
6150 * @start: start position of the space already reserved
6151 * @len: the len of the space already reserved
6152 *
6153 * This must be matched with a call to btrfs_delalloc_reserve_space. This is
6154 * called in the case that we don't need the metadata AND data reservations
6155 * anymore. So if there is an error or we insert an inline extent.
6156 *
6157 * This function will release the metadata space that was not used and will
6158 * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
6159 * list if there are no delalloc bytes left.
6160 * Also it will handle the qgroup reserved space.
6161 */
6162 void btrfs_delalloc_release_space(struct inode *inode, u64 start, u64 len)
6163 {
6164 btrfs_delalloc_release_metadata(inode, len);
6165 btrfs_free_reserved_data_space(inode, start, len);
6166 }
6167
6168 static int update_block_group(struct btrfs_trans_handle *trans,
6169 struct btrfs_root *root, u64 bytenr,
6170 u64 num_bytes, int alloc)
6171 {
6172 struct btrfs_block_group_cache *cache = NULL;
6173 struct btrfs_fs_info *info = root->fs_info;
6174 u64 total = num_bytes;
6175 u64 old_val;
6176 u64 byte_in_group;
6177 int factor;
6178
6179 /* block accounting for super block */
6180 spin_lock(&info->delalloc_root_lock);
6181 old_val = btrfs_super_bytes_used(info->super_copy);
6182 if (alloc)
6183 old_val += num_bytes;
6184 else
6185 old_val -= num_bytes;
6186 btrfs_set_super_bytes_used(info->super_copy, old_val);
6187 spin_unlock(&info->delalloc_root_lock);
6188
6189 while (total) {
6190 cache = btrfs_lookup_block_group(info, bytenr);
6191 if (!cache)
6192 return -ENOENT;
6193 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
6194 BTRFS_BLOCK_GROUP_RAID1 |
6195 BTRFS_BLOCK_GROUP_RAID10))
6196 factor = 2;
6197 else
6198 factor = 1;
6199 /*
6200 * If this block group has free space cache written out, we
6201 * need to make sure to load it if we are removing space. This
6202 * is because we need the unpinning stage to actually add the
6203 * space back to the block group, otherwise we will leak space.
6204 */
6205 if (!alloc && cache->cached == BTRFS_CACHE_NO)
6206 cache_block_group(cache, 1);
6207
6208 byte_in_group = bytenr - cache->key.objectid;
6209 WARN_ON(byte_in_group > cache->key.offset);
6210
6211 spin_lock(&cache->space_info->lock);
6212 spin_lock(&cache->lock);
6213
6214 if (btrfs_test_opt(root->fs_info, SPACE_CACHE) &&
6215 cache->disk_cache_state < BTRFS_DC_CLEAR)
6216 cache->disk_cache_state = BTRFS_DC_CLEAR;
6217
6218 old_val = btrfs_block_group_used(&cache->item);
6219 num_bytes = min(total, cache->key.offset - byte_in_group);
6220 if (alloc) {
6221 old_val += num_bytes;
6222 btrfs_set_block_group_used(&cache->item, old_val);
6223 cache->reserved -= num_bytes;
6224 cache->space_info->bytes_reserved -= num_bytes;
6225 cache->space_info->bytes_used += num_bytes;
6226 cache->space_info->disk_used += num_bytes * factor;
6227 spin_unlock(&cache->lock);
6228 spin_unlock(&cache->space_info->lock);
6229 } else {
6230 old_val -= num_bytes;
6231 btrfs_set_block_group_used(&cache->item, old_val);
6232 cache->pinned += num_bytes;
6233 cache->space_info->bytes_pinned += num_bytes;
6234 cache->space_info->bytes_used -= num_bytes;
6235 cache->space_info->disk_used -= num_bytes * factor;
6236 spin_unlock(&cache->lock);
6237 spin_unlock(&cache->space_info->lock);
6238
6239 trace_btrfs_space_reservation(root->fs_info, "pinned",
6240 cache->space_info->flags,
6241 num_bytes, 1);
6242 set_extent_dirty(info->pinned_extents,
6243 bytenr, bytenr + num_bytes - 1,
6244 GFP_NOFS | __GFP_NOFAIL);
6245 }
6246
6247 spin_lock(&trans->transaction->dirty_bgs_lock);
6248 if (list_empty(&cache->dirty_list)) {
6249 list_add_tail(&cache->dirty_list,
6250 &trans->transaction->dirty_bgs);
6251 trans->transaction->num_dirty_bgs++;
6252 btrfs_get_block_group(cache);
6253 }
6254 spin_unlock(&trans->transaction->dirty_bgs_lock);
6255
6256 /*
6257 * No longer have used bytes in this block group, queue it for
6258 * deletion. We do this after adding the block group to the
6259 * dirty list to avoid races between cleaner kthread and space
6260 * cache writeout.
6261 */
6262 if (!alloc && old_val == 0) {
6263 spin_lock(&info->unused_bgs_lock);
6264 if (list_empty(&cache->bg_list)) {
6265 btrfs_get_block_group(cache);
6266 list_add_tail(&cache->bg_list,
6267 &info->unused_bgs);
6268 }
6269 spin_unlock(&info->unused_bgs_lock);
6270 }
6271
6272 btrfs_put_block_group(cache);
6273 total -= num_bytes;
6274 bytenr += num_bytes;
6275 }
6276 return 0;
6277 }
6278
6279 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
6280 {
6281 struct btrfs_block_group_cache *cache;
6282 u64 bytenr;
6283
6284 spin_lock(&root->fs_info->block_group_cache_lock);
6285 bytenr = root->fs_info->first_logical_byte;
6286 spin_unlock(&root->fs_info->block_group_cache_lock);
6287
6288 if (bytenr < (u64)-1)
6289 return bytenr;
6290
6291 cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
6292 if (!cache)
6293 return 0;
6294
6295 bytenr = cache->key.objectid;
6296 btrfs_put_block_group(cache);
6297
6298 return bytenr;
6299 }
6300
6301 static int pin_down_extent(struct btrfs_root *root,
6302 struct btrfs_block_group_cache *cache,
6303 u64 bytenr, u64 num_bytes, int reserved)
6304 {
6305 spin_lock(&cache->space_info->lock);
6306 spin_lock(&cache->lock);
6307 cache->pinned += num_bytes;
6308 cache->space_info->bytes_pinned += num_bytes;
6309 if (reserved) {
6310 cache->reserved -= num_bytes;
6311 cache->space_info->bytes_reserved -= num_bytes;
6312 }
6313 spin_unlock(&cache->lock);
6314 spin_unlock(&cache->space_info->lock);
6315
6316 trace_btrfs_space_reservation(root->fs_info, "pinned",
6317 cache->space_info->flags, num_bytes, 1);
6318 set_extent_dirty(root->fs_info->pinned_extents, bytenr,
6319 bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
6320 return 0;
6321 }
6322
6323 /*
6324 * this function must be called within transaction
6325 */
6326 int btrfs_pin_extent(struct btrfs_root *root,
6327 u64 bytenr, u64 num_bytes, int reserved)
6328 {
6329 struct btrfs_block_group_cache *cache;
6330
6331 cache = btrfs_lookup_block_group(root->fs_info, bytenr);
6332 BUG_ON(!cache); /* Logic error */
6333
6334 pin_down_extent(root, cache, bytenr, num_bytes, reserved);
6335
6336 btrfs_put_block_group(cache);
6337 return 0;
6338 }
6339
6340 /*
6341 * this function must be called within transaction
6342 */
6343 int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
6344 u64 bytenr, u64 num_bytes)
6345 {
6346 struct btrfs_block_group_cache *cache;
6347 int ret;
6348
6349 cache = btrfs_lookup_block_group(root->fs_info, bytenr);
6350 if (!cache)
6351 return -EINVAL;
6352
6353 /*
6354 * pull in the free space cache (if any) so that our pin
6355 * removes the free space from the cache. We have load_only set
6356 * to one because the slow code to read in the free extents does check
6357 * the pinned extents.
6358 */
6359 cache_block_group(cache, 1);
6360
6361 pin_down_extent(root, cache, bytenr, num_bytes, 0);
6362
6363 /* remove us from the free space cache (if we're there at all) */
6364 ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
6365 btrfs_put_block_group(cache);
6366 return ret;
6367 }
6368
6369 static int __exclude_logged_extent(struct btrfs_root *root, u64 start, u64 num_bytes)
6370 {
6371 int ret;
6372 struct btrfs_block_group_cache *block_group;
6373 struct btrfs_caching_control *caching_ctl;
6374
6375 block_group = btrfs_lookup_block_group(root->fs_info, start);
6376 if (!block_group)
6377 return -EINVAL;
6378
6379 cache_block_group(block_group, 0);
6380 caching_ctl = get_caching_control(block_group);
6381
6382 if (!caching_ctl) {
6383 /* Logic error */
6384 BUG_ON(!block_group_cache_done(block_group));
6385 ret = btrfs_remove_free_space(block_group, start, num_bytes);
6386 } else {
6387 mutex_lock(&caching_ctl->mutex);
6388
6389 if (start >= caching_ctl->progress) {
6390 ret = add_excluded_extent(root, start, num_bytes);
6391 } else if (start + num_bytes <= caching_ctl->progress) {
6392 ret = btrfs_remove_free_space(block_group,
6393 start, num_bytes);
6394 } else {
6395 num_bytes = caching_ctl->progress - start;
6396 ret = btrfs_remove_free_space(block_group,
6397 start, num_bytes);
6398 if (ret)
6399 goto out_lock;
6400
6401 num_bytes = (start + num_bytes) -
6402 caching_ctl->progress;
6403 start = caching_ctl->progress;
6404 ret = add_excluded_extent(root, start, num_bytes);
6405 }
6406 out_lock:
6407 mutex_unlock(&caching_ctl->mutex);
6408 put_caching_control(caching_ctl);
6409 }
6410 btrfs_put_block_group(block_group);
6411 return ret;
6412 }
6413
6414 int btrfs_exclude_logged_extents(struct btrfs_root *log,
6415 struct extent_buffer *eb)
6416 {
6417 struct btrfs_file_extent_item *item;
6418 struct btrfs_key key;
6419 int found_type;
6420 int i;
6421
6422 if (!btrfs_fs_incompat(log->fs_info, MIXED_GROUPS))
6423 return 0;
6424
6425 for (i = 0; i < btrfs_header_nritems(eb); i++) {
6426 btrfs_item_key_to_cpu(eb, &key, i);
6427 if (key.type != BTRFS_EXTENT_DATA_KEY)
6428 continue;
6429 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
6430 found_type = btrfs_file_extent_type(eb, item);
6431 if (found_type == BTRFS_FILE_EXTENT_INLINE)
6432 continue;
6433 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
6434 continue;
6435 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
6436 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
6437 __exclude_logged_extent(log, key.objectid, key.offset);
6438 }
6439
6440 return 0;
6441 }
6442
6443 static void
6444 btrfs_inc_block_group_reservations(struct btrfs_block_group_cache *bg)
6445 {
6446 atomic_inc(&bg->reservations);
6447 }
6448
6449 void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
6450 const u64 start)
6451 {
6452 struct btrfs_block_group_cache *bg;
6453
6454 bg = btrfs_lookup_block_group(fs_info, start);
6455 ASSERT(bg);
6456 if (atomic_dec_and_test(&bg->reservations))
6457 wake_up_atomic_t(&bg->reservations);
6458 btrfs_put_block_group(bg);
6459 }
6460
6461 static int btrfs_wait_bg_reservations_atomic_t(atomic_t *a)
6462 {
6463 schedule();
6464 return 0;
6465 }
6466
6467 void btrfs_wait_block_group_reservations(struct btrfs_block_group_cache *bg)
6468 {
6469 struct btrfs_space_info *space_info = bg->space_info;
6470
6471 ASSERT(bg->ro);
6472
6473 if (!(bg->flags & BTRFS_BLOCK_GROUP_DATA))
6474 return;
6475
6476 /*
6477 * Our block group is read only but before we set it to read only,
6478 * some task might have had allocated an extent from it already, but it
6479 * has not yet created a respective ordered extent (and added it to a
6480 * root's list of ordered extents).
6481 * Therefore wait for any task currently allocating extents, since the
6482 * block group's reservations counter is incremented while a read lock
6483 * on the groups' semaphore is held and decremented after releasing
6484 * the read access on that semaphore and creating the ordered extent.
6485 */
6486 down_write(&space_info->groups_sem);
6487 up_write(&space_info->groups_sem);
6488
6489 wait_on_atomic_t(&bg->reservations,
6490 btrfs_wait_bg_reservations_atomic_t,
6491 TASK_UNINTERRUPTIBLE);
6492 }
6493
6494 /**
6495 * btrfs_add_reserved_bytes - update the block_group and space info counters
6496 * @cache: The cache we are manipulating
6497 * @ram_bytes: The number of bytes of file content, and will be same to
6498 * @num_bytes except for the compress path.
6499 * @num_bytes: The number of bytes in question
6500 * @delalloc: The blocks are allocated for the delalloc write
6501 *
6502 * This is called by the allocator when it reserves space. Metadata
6503 * reservations should be called with RESERVE_ALLOC so we do the proper
6504 * ENOSPC accounting. For data we handle the reservation through clearing the
6505 * delalloc bits in the io_tree. We have to do this since we could end up
6506 * allocating less disk space for the amount of data we have reserved in the
6507 * case of compression.
6508 *
6509 * If this is a reservation and the block group has become read only we cannot
6510 * make the reservation and return -EAGAIN, otherwise this function always
6511 * succeeds.
6512 */
6513 static int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
6514 u64 ram_bytes, u64 num_bytes, int delalloc)
6515 {
6516 struct btrfs_space_info *space_info = cache->space_info;
6517 int ret = 0;
6518
6519 spin_lock(&space_info->lock);
6520 spin_lock(&cache->lock);
6521 if (cache->ro) {
6522 ret = -EAGAIN;
6523 } else {
6524 cache->reserved += num_bytes;
6525 space_info->bytes_reserved += num_bytes;
6526
6527 trace_btrfs_space_reservation(cache->fs_info,
6528 "space_info", space_info->flags,
6529 ram_bytes, 0);
6530 space_info->bytes_may_use -= ram_bytes;
6531 if (delalloc)
6532 cache->delalloc_bytes += num_bytes;
6533 }
6534 spin_unlock(&cache->lock);
6535 spin_unlock(&space_info->lock);
6536 return ret;
6537 }
6538
6539 /**
6540 * btrfs_free_reserved_bytes - update the block_group and space info counters
6541 * @cache: The cache we are manipulating
6542 * @num_bytes: The number of bytes in question
6543 * @delalloc: The blocks are allocated for the delalloc write
6544 *
6545 * This is called by somebody who is freeing space that was never actually used
6546 * on disk. For example if you reserve some space for a new leaf in transaction
6547 * A and before transaction A commits you free that leaf, you call this with
6548 * reserve set to 0 in order to clear the reservation.
6549 */
6550
6551 static int btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
6552 u64 num_bytes, int delalloc)
6553 {
6554 struct btrfs_space_info *space_info = cache->space_info;
6555 int ret = 0;
6556
6557 spin_lock(&space_info->lock);
6558 spin_lock(&cache->lock);
6559 if (cache->ro)
6560 space_info->bytes_readonly += num_bytes;
6561 cache->reserved -= num_bytes;
6562 space_info->bytes_reserved -= num_bytes;
6563
6564 if (delalloc)
6565 cache->delalloc_bytes -= num_bytes;
6566 spin_unlock(&cache->lock);
6567 spin_unlock(&space_info->lock);
6568 return ret;
6569 }
6570 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
6571 struct btrfs_root *root)
6572 {
6573 struct btrfs_fs_info *fs_info = root->fs_info;
6574 struct btrfs_caching_control *next;
6575 struct btrfs_caching_control *caching_ctl;
6576 struct btrfs_block_group_cache *cache;
6577
6578 down_write(&fs_info->commit_root_sem);
6579
6580 list_for_each_entry_safe(caching_ctl, next,
6581 &fs_info->caching_block_groups, list) {
6582 cache = caching_ctl->block_group;
6583 if (block_group_cache_done(cache)) {
6584 cache->last_byte_to_unpin = (u64)-1;
6585 list_del_init(&caching_ctl->list);
6586 put_caching_control(caching_ctl);
6587 } else {
6588 cache->last_byte_to_unpin = caching_ctl->progress;
6589 }
6590 }
6591
6592 if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6593 fs_info->pinned_extents = &fs_info->freed_extents[1];
6594 else
6595 fs_info->pinned_extents = &fs_info->freed_extents[0];
6596
6597 up_write(&fs_info->commit_root_sem);
6598
6599 update_global_block_rsv(fs_info);
6600 }
6601
6602 /*
6603 * Returns the free cluster for the given space info and sets empty_cluster to
6604 * what it should be based on the mount options.
6605 */
6606 static struct btrfs_free_cluster *
6607 fetch_cluster_info(struct btrfs_root *root, struct btrfs_space_info *space_info,
6608 u64 *empty_cluster)
6609 {
6610 struct btrfs_free_cluster *ret = NULL;
6611 bool ssd = btrfs_test_opt(root->fs_info, SSD);
6612
6613 *empty_cluster = 0;
6614 if (btrfs_mixed_space_info(space_info))
6615 return ret;
6616
6617 if (ssd)
6618 *empty_cluster = SZ_2M;
6619 if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
6620 ret = &root->fs_info->meta_alloc_cluster;
6621 if (!ssd)
6622 *empty_cluster = SZ_64K;
6623 } else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) && ssd) {
6624 ret = &root->fs_info->data_alloc_cluster;
6625 }
6626
6627 return ret;
6628 }
6629
6630 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end,
6631 const bool return_free_space)
6632 {
6633 struct btrfs_fs_info *fs_info = root->fs_info;
6634 struct btrfs_block_group_cache *cache = NULL;
6635 struct btrfs_space_info *space_info;
6636 struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
6637 struct btrfs_free_cluster *cluster = NULL;
6638 u64 len;
6639 u64 total_unpinned = 0;
6640 u64 empty_cluster = 0;
6641 bool readonly;
6642
6643 while (start <= end) {
6644 readonly = false;
6645 if (!cache ||
6646 start >= cache->key.objectid + cache->key.offset) {
6647 if (cache)
6648 btrfs_put_block_group(cache);
6649 total_unpinned = 0;
6650 cache = btrfs_lookup_block_group(fs_info, start);
6651 BUG_ON(!cache); /* Logic error */
6652
6653 cluster = fetch_cluster_info(root,
6654 cache->space_info,
6655 &empty_cluster);
6656 empty_cluster <<= 1;
6657 }
6658
6659 len = cache->key.objectid + cache->key.offset - start;
6660 len = min(len, end + 1 - start);
6661
6662 if (start < cache->last_byte_to_unpin) {
6663 len = min(len, cache->last_byte_to_unpin - start);
6664 if (return_free_space)
6665 btrfs_add_free_space(cache, start, len);
6666 }
6667
6668 start += len;
6669 total_unpinned += len;
6670 space_info = cache->space_info;
6671
6672 /*
6673 * If this space cluster has been marked as fragmented and we've
6674 * unpinned enough in this block group to potentially allow a
6675 * cluster to be created inside of it go ahead and clear the
6676 * fragmented check.
6677 */
6678 if (cluster && cluster->fragmented &&
6679 total_unpinned > empty_cluster) {
6680 spin_lock(&cluster->lock);
6681 cluster->fragmented = 0;
6682 spin_unlock(&cluster->lock);
6683 }
6684
6685 spin_lock(&space_info->lock);
6686 spin_lock(&cache->lock);
6687 cache->pinned -= len;
6688 space_info->bytes_pinned -= len;
6689
6690 trace_btrfs_space_reservation(fs_info, "pinned",
6691 space_info->flags, len, 0);
6692 space_info->max_extent_size = 0;
6693 percpu_counter_add(&space_info->total_bytes_pinned, -len);
6694 if (cache->ro) {
6695 space_info->bytes_readonly += len;
6696 readonly = true;
6697 }
6698 spin_unlock(&cache->lock);
6699 if (!readonly && return_free_space &&
6700 global_rsv->space_info == space_info) {
6701 u64 to_add = len;
6702 WARN_ON(!return_free_space);
6703 spin_lock(&global_rsv->lock);
6704 if (!global_rsv->full) {
6705 to_add = min(len, global_rsv->size -
6706 global_rsv->reserved);
6707 global_rsv->reserved += to_add;
6708 space_info->bytes_may_use += to_add;
6709 if (global_rsv->reserved >= global_rsv->size)
6710 global_rsv->full = 1;
6711 trace_btrfs_space_reservation(fs_info,
6712 "space_info",
6713 space_info->flags,
6714 to_add, 1);
6715 len -= to_add;
6716 }
6717 spin_unlock(&global_rsv->lock);
6718 /* Add to any tickets we may have */
6719 if (len)
6720 space_info_add_new_bytes(fs_info, space_info,
6721 len);
6722 }
6723 spin_unlock(&space_info->lock);
6724 }
6725
6726 if (cache)
6727 btrfs_put_block_group(cache);
6728 return 0;
6729 }
6730
6731 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
6732 struct btrfs_root *root)
6733 {
6734 struct btrfs_fs_info *fs_info = root->fs_info;
6735 struct btrfs_block_group_cache *block_group, *tmp;
6736 struct list_head *deleted_bgs;
6737 struct extent_io_tree *unpin;
6738 u64 start;
6739 u64 end;
6740 int ret;
6741
6742 if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6743 unpin = &fs_info->freed_extents[1];
6744 else
6745 unpin = &fs_info->freed_extents[0];
6746
6747 while (!trans->aborted) {
6748 mutex_lock(&fs_info->unused_bg_unpin_mutex);
6749 ret = find_first_extent_bit(unpin, 0, &start, &end,
6750 EXTENT_DIRTY, NULL);
6751 if (ret) {
6752 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6753 break;
6754 }
6755
6756 if (btrfs_test_opt(root->fs_info, DISCARD))
6757 ret = btrfs_discard_extent(root, start,
6758 end + 1 - start, NULL);
6759
6760 clear_extent_dirty(unpin, start, end);
6761 unpin_extent_range(root, start, end, true);
6762 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6763 cond_resched();
6764 }
6765
6766 /*
6767 * Transaction is finished. We don't need the lock anymore. We
6768 * do need to clean up the block groups in case of a transaction
6769 * abort.
6770 */
6771 deleted_bgs = &trans->transaction->deleted_bgs;
6772 list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
6773 u64 trimmed = 0;
6774
6775 ret = -EROFS;
6776 if (!trans->aborted)
6777 ret = btrfs_discard_extent(root,
6778 block_group->key.objectid,
6779 block_group->key.offset,
6780 &trimmed);
6781
6782 list_del_init(&block_group->bg_list);
6783 btrfs_put_block_group_trimming(block_group);
6784 btrfs_put_block_group(block_group);
6785
6786 if (ret) {
6787 const char *errstr = btrfs_decode_error(ret);
6788 btrfs_warn(fs_info,
6789 "Discard failed while removing blockgroup: errno=%d %s\n",
6790 ret, errstr);
6791 }
6792 }
6793
6794 return 0;
6795 }
6796
6797 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, u64 num_bytes,
6798 u64 owner, u64 root_objectid)
6799 {
6800 struct btrfs_space_info *space_info;
6801 u64 flags;
6802
6803 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6804 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
6805 flags = BTRFS_BLOCK_GROUP_SYSTEM;
6806 else
6807 flags = BTRFS_BLOCK_GROUP_METADATA;
6808 } else {
6809 flags = BTRFS_BLOCK_GROUP_DATA;
6810 }
6811
6812 space_info = __find_space_info(fs_info, flags);
6813 BUG_ON(!space_info); /* Logic bug */
6814 percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
6815 }
6816
6817
6818 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
6819 struct btrfs_root *root,
6820 struct btrfs_delayed_ref_node *node, u64 parent,
6821 u64 root_objectid, u64 owner_objectid,
6822 u64 owner_offset, int refs_to_drop,
6823 struct btrfs_delayed_extent_op *extent_op)
6824 {
6825 struct btrfs_key key;
6826 struct btrfs_path *path;
6827 struct btrfs_fs_info *info = root->fs_info;
6828 struct btrfs_root *extent_root = info->extent_root;
6829 struct extent_buffer *leaf;
6830 struct btrfs_extent_item *ei;
6831 struct btrfs_extent_inline_ref *iref;
6832 int ret;
6833 int is_data;
6834 int extent_slot = 0;
6835 int found_extent = 0;
6836 int num_to_del = 1;
6837 u32 item_size;
6838 u64 refs;
6839 u64 bytenr = node->bytenr;
6840 u64 num_bytes = node->num_bytes;
6841 int last_ref = 0;
6842 bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6843 SKINNY_METADATA);
6844
6845 path = btrfs_alloc_path();
6846 if (!path)
6847 return -ENOMEM;
6848
6849 path->reada = READA_FORWARD;
6850 path->leave_spinning = 1;
6851
6852 is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
6853 BUG_ON(!is_data && refs_to_drop != 1);
6854
6855 if (is_data)
6856 skinny_metadata = 0;
6857
6858 ret = lookup_extent_backref(trans, extent_root, path, &iref,
6859 bytenr, num_bytes, parent,
6860 root_objectid, owner_objectid,
6861 owner_offset);
6862 if (ret == 0) {
6863 extent_slot = path->slots[0];
6864 while (extent_slot >= 0) {
6865 btrfs_item_key_to_cpu(path->nodes[0], &key,
6866 extent_slot);
6867 if (key.objectid != bytenr)
6868 break;
6869 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
6870 key.offset == num_bytes) {
6871 found_extent = 1;
6872 break;
6873 }
6874 if (key.type == BTRFS_METADATA_ITEM_KEY &&
6875 key.offset == owner_objectid) {
6876 found_extent = 1;
6877 break;
6878 }
6879 if (path->slots[0] - extent_slot > 5)
6880 break;
6881 extent_slot--;
6882 }
6883 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6884 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
6885 if (found_extent && item_size < sizeof(*ei))
6886 found_extent = 0;
6887 #endif
6888 if (!found_extent) {
6889 BUG_ON(iref);
6890 ret = remove_extent_backref(trans, extent_root, path,
6891 NULL, refs_to_drop,
6892 is_data, &last_ref);
6893 if (ret) {
6894 btrfs_abort_transaction(trans, ret);
6895 goto out;
6896 }
6897 btrfs_release_path(path);
6898 path->leave_spinning = 1;
6899
6900 key.objectid = bytenr;
6901 key.type = BTRFS_EXTENT_ITEM_KEY;
6902 key.offset = num_bytes;
6903
6904 if (!is_data && skinny_metadata) {
6905 key.type = BTRFS_METADATA_ITEM_KEY;
6906 key.offset = owner_objectid;
6907 }
6908
6909 ret = btrfs_search_slot(trans, extent_root,
6910 &key, path, -1, 1);
6911 if (ret > 0 && skinny_metadata && path->slots[0]) {
6912 /*
6913 * Couldn't find our skinny metadata item,
6914 * see if we have ye olde extent item.
6915 */
6916 path->slots[0]--;
6917 btrfs_item_key_to_cpu(path->nodes[0], &key,
6918 path->slots[0]);
6919 if (key.objectid == bytenr &&
6920 key.type == BTRFS_EXTENT_ITEM_KEY &&
6921 key.offset == num_bytes)
6922 ret = 0;
6923 }
6924
6925 if (ret > 0 && skinny_metadata) {
6926 skinny_metadata = false;
6927 key.objectid = bytenr;
6928 key.type = BTRFS_EXTENT_ITEM_KEY;
6929 key.offset = num_bytes;
6930 btrfs_release_path(path);
6931 ret = btrfs_search_slot(trans, extent_root,
6932 &key, path, -1, 1);
6933 }
6934
6935 if (ret) {
6936 btrfs_err(info, "umm, got %d back from search, was looking for %llu",
6937 ret, bytenr);
6938 if (ret > 0)
6939 btrfs_print_leaf(extent_root,
6940 path->nodes[0]);
6941 }
6942 if (ret < 0) {
6943 btrfs_abort_transaction(trans, ret);
6944 goto out;
6945 }
6946 extent_slot = path->slots[0];
6947 }
6948 } else if (WARN_ON(ret == -ENOENT)) {
6949 btrfs_print_leaf(extent_root, path->nodes[0]);
6950 btrfs_err(info,
6951 "unable to find ref byte nr %llu parent %llu root %llu owner %llu offset %llu",
6952 bytenr, parent, root_objectid, owner_objectid,
6953 owner_offset);
6954 btrfs_abort_transaction(trans, ret);
6955 goto out;
6956 } else {
6957 btrfs_abort_transaction(trans, ret);
6958 goto out;
6959 }
6960
6961 leaf = path->nodes[0];
6962 item_size = btrfs_item_size_nr(leaf, extent_slot);
6963 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6964 if (item_size < sizeof(*ei)) {
6965 BUG_ON(found_extent || extent_slot != path->slots[0]);
6966 ret = convert_extent_item_v0(trans, extent_root, path,
6967 owner_objectid, 0);
6968 if (ret < 0) {
6969 btrfs_abort_transaction(trans, ret);
6970 goto out;
6971 }
6972
6973 btrfs_release_path(path);
6974 path->leave_spinning = 1;
6975
6976 key.objectid = bytenr;
6977 key.type = BTRFS_EXTENT_ITEM_KEY;
6978 key.offset = num_bytes;
6979
6980 ret = btrfs_search_slot(trans, extent_root, &key, path,
6981 -1, 1);
6982 if (ret) {
6983 btrfs_err(info, "umm, got %d back from search, was looking for %llu",
6984 ret, bytenr);
6985 btrfs_print_leaf(extent_root, path->nodes[0]);
6986 }
6987 if (ret < 0) {
6988 btrfs_abort_transaction(trans, ret);
6989 goto out;
6990 }
6991
6992 extent_slot = path->slots[0];
6993 leaf = path->nodes[0];
6994 item_size = btrfs_item_size_nr(leaf, extent_slot);
6995 }
6996 #endif
6997 BUG_ON(item_size < sizeof(*ei));
6998 ei = btrfs_item_ptr(leaf, extent_slot,
6999 struct btrfs_extent_item);
7000 if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
7001 key.type == BTRFS_EXTENT_ITEM_KEY) {
7002 struct btrfs_tree_block_info *bi;
7003 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
7004 bi = (struct btrfs_tree_block_info *)(ei + 1);
7005 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
7006 }
7007
7008 refs = btrfs_extent_refs(leaf, ei);
7009 if (refs < refs_to_drop) {
7010 btrfs_err(info, "trying to drop %d refs but we only have %Lu "
7011 "for bytenr %Lu", refs_to_drop, refs, bytenr);
7012 ret = -EINVAL;
7013 btrfs_abort_transaction(trans, ret);
7014 goto out;
7015 }
7016 refs -= refs_to_drop;
7017
7018 if (refs > 0) {
7019 if (extent_op)
7020 __run_delayed_extent_op(extent_op, leaf, ei);
7021 /*
7022 * In the case of inline back ref, reference count will
7023 * be updated by remove_extent_backref
7024 */
7025 if (iref) {
7026 BUG_ON(!found_extent);
7027 } else {
7028 btrfs_set_extent_refs(leaf, ei, refs);
7029 btrfs_mark_buffer_dirty(leaf);
7030 }
7031 if (found_extent) {
7032 ret = remove_extent_backref(trans, extent_root, path,
7033 iref, refs_to_drop,
7034 is_data, &last_ref);
7035 if (ret) {
7036 btrfs_abort_transaction(trans, ret);
7037 goto out;
7038 }
7039 }
7040 add_pinned_bytes(root->fs_info, -num_bytes, owner_objectid,
7041 root_objectid);
7042 } else {
7043 if (found_extent) {
7044 BUG_ON(is_data && refs_to_drop !=
7045 extent_data_ref_count(path, iref));
7046 if (iref) {
7047 BUG_ON(path->slots[0] != extent_slot);
7048 } else {
7049 BUG_ON(path->slots[0] != extent_slot + 1);
7050 path->slots[0] = extent_slot;
7051 num_to_del = 2;
7052 }
7053 }
7054
7055 last_ref = 1;
7056 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
7057 num_to_del);
7058 if (ret) {
7059 btrfs_abort_transaction(trans, ret);
7060 goto out;
7061 }
7062 btrfs_release_path(path);
7063
7064 if (is_data) {
7065 ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
7066 if (ret) {
7067 btrfs_abort_transaction(trans, ret);
7068 goto out;
7069 }
7070 }
7071
7072 ret = add_to_free_space_tree(trans, root->fs_info, bytenr,
7073 num_bytes);
7074 if (ret) {
7075 btrfs_abort_transaction(trans, ret);
7076 goto out;
7077 }
7078
7079 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
7080 if (ret) {
7081 btrfs_abort_transaction(trans, ret);
7082 goto out;
7083 }
7084 }
7085 btrfs_release_path(path);
7086
7087 out:
7088 btrfs_free_path(path);
7089 return ret;
7090 }
7091
7092 /*
7093 * when we free an block, it is possible (and likely) that we free the last
7094 * delayed ref for that extent as well. This searches the delayed ref tree for
7095 * a given extent, and if there are no other delayed refs to be processed, it
7096 * removes it from the tree.
7097 */
7098 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
7099 struct btrfs_root *root, u64 bytenr)
7100 {
7101 struct btrfs_delayed_ref_head *head;
7102 struct btrfs_delayed_ref_root *delayed_refs;
7103 int ret = 0;
7104
7105 delayed_refs = &trans->transaction->delayed_refs;
7106 spin_lock(&delayed_refs->lock);
7107 head = btrfs_find_delayed_ref_head(trans, bytenr);
7108 if (!head)
7109 goto out_delayed_unlock;
7110
7111 spin_lock(&head->lock);
7112 if (!list_empty(&head->ref_list))
7113 goto out;
7114
7115 if (head->extent_op) {
7116 if (!head->must_insert_reserved)
7117 goto out;
7118 btrfs_free_delayed_extent_op(head->extent_op);
7119 head->extent_op = NULL;
7120 }
7121
7122 /*
7123 * waiting for the lock here would deadlock. If someone else has it
7124 * locked they are already in the process of dropping it anyway
7125 */
7126 if (!mutex_trylock(&head->mutex))
7127 goto out;
7128
7129 /*
7130 * at this point we have a head with no other entries. Go
7131 * ahead and process it.
7132 */
7133 head->node.in_tree = 0;
7134 rb_erase(&head->href_node, &delayed_refs->href_root);
7135
7136 atomic_dec(&delayed_refs->num_entries);
7137
7138 /*
7139 * we don't take a ref on the node because we're removing it from the
7140 * tree, so we just steal the ref the tree was holding.
7141 */
7142 delayed_refs->num_heads--;
7143 if (head->processing == 0)
7144 delayed_refs->num_heads_ready--;
7145 head->processing = 0;
7146 spin_unlock(&head->lock);
7147 spin_unlock(&delayed_refs->lock);
7148
7149 BUG_ON(head->extent_op);
7150 if (head->must_insert_reserved)
7151 ret = 1;
7152
7153 mutex_unlock(&head->mutex);
7154 btrfs_put_delayed_ref(&head->node);
7155 return ret;
7156 out:
7157 spin_unlock(&head->lock);
7158
7159 out_delayed_unlock:
7160 spin_unlock(&delayed_refs->lock);
7161 return 0;
7162 }
7163
7164 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
7165 struct btrfs_root *root,
7166 struct extent_buffer *buf,
7167 u64 parent, int last_ref)
7168 {
7169 int pin = 1;
7170 int ret;
7171
7172 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7173 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
7174 buf->start, buf->len,
7175 parent, root->root_key.objectid,
7176 btrfs_header_level(buf),
7177 BTRFS_DROP_DELAYED_REF, NULL);
7178 BUG_ON(ret); /* -ENOMEM */
7179 }
7180
7181 if (!last_ref)
7182 return;
7183
7184 if (btrfs_header_generation(buf) == trans->transid) {
7185 struct btrfs_block_group_cache *cache;
7186
7187 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7188 ret = check_ref_cleanup(trans, root, buf->start);
7189 if (!ret)
7190 goto out;
7191 }
7192
7193 cache = btrfs_lookup_block_group(root->fs_info, buf->start);
7194
7195 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
7196 pin_down_extent(root, cache, buf->start, buf->len, 1);
7197 btrfs_put_block_group(cache);
7198 goto out;
7199 }
7200
7201 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
7202
7203 btrfs_add_free_space(cache, buf->start, buf->len);
7204 btrfs_free_reserved_bytes(cache, buf->len, 0);
7205 btrfs_put_block_group(cache);
7206 trace_btrfs_reserved_extent_free(root, buf->start, buf->len);
7207 pin = 0;
7208 }
7209 out:
7210 if (pin)
7211 add_pinned_bytes(root->fs_info, buf->len,
7212 btrfs_header_level(buf),
7213 root->root_key.objectid);
7214
7215 /*
7216 * Deleting the buffer, clear the corrupt flag since it doesn't matter
7217 * anymore.
7218 */
7219 clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
7220 }
7221
7222 /* Can return -ENOMEM */
7223 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
7224 u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
7225 u64 owner, u64 offset)
7226 {
7227 int ret;
7228 struct btrfs_fs_info *fs_info = root->fs_info;
7229
7230 if (btrfs_is_testing(fs_info))
7231 return 0;
7232
7233 add_pinned_bytes(root->fs_info, num_bytes, owner, root_objectid);
7234
7235 /*
7236 * tree log blocks never actually go into the extent allocation
7237 * tree, just update pinning info and exit early.
7238 */
7239 if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
7240 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
7241 /* unlocks the pinned mutex */
7242 btrfs_pin_extent(root, bytenr, num_bytes, 1);
7243 ret = 0;
7244 } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
7245 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
7246 num_bytes,
7247 parent, root_objectid, (int)owner,
7248 BTRFS_DROP_DELAYED_REF, NULL);
7249 } else {
7250 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
7251 num_bytes,
7252 parent, root_objectid, owner,
7253 offset, 0,
7254 BTRFS_DROP_DELAYED_REF, NULL);
7255 }
7256 return ret;
7257 }
7258
7259 /*
7260 * when we wait for progress in the block group caching, its because
7261 * our allocation attempt failed at least once. So, we must sleep
7262 * and let some progress happen before we try again.
7263 *
7264 * This function will sleep at least once waiting for new free space to
7265 * show up, and then it will check the block group free space numbers
7266 * for our min num_bytes. Another option is to have it go ahead
7267 * and look in the rbtree for a free extent of a given size, but this
7268 * is a good start.
7269 *
7270 * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
7271 * any of the information in this block group.
7272 */
7273 static noinline void
7274 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
7275 u64 num_bytes)
7276 {
7277 struct btrfs_caching_control *caching_ctl;
7278
7279 caching_ctl = get_caching_control(cache);
7280 if (!caching_ctl)
7281 return;
7282
7283 wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
7284 (cache->free_space_ctl->free_space >= num_bytes));
7285
7286 put_caching_control(caching_ctl);
7287 }
7288
7289 static noinline int
7290 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
7291 {
7292 struct btrfs_caching_control *caching_ctl;
7293 int ret = 0;
7294
7295 caching_ctl = get_caching_control(cache);
7296 if (!caching_ctl)
7297 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
7298
7299 wait_event(caching_ctl->wait, block_group_cache_done(cache));
7300 if (cache->cached == BTRFS_CACHE_ERROR)
7301 ret = -EIO;
7302 put_caching_control(caching_ctl);
7303 return ret;
7304 }
7305
7306 int __get_raid_index(u64 flags)
7307 {
7308 if (flags & BTRFS_BLOCK_GROUP_RAID10)
7309 return BTRFS_RAID_RAID10;
7310 else if (flags & BTRFS_BLOCK_GROUP_RAID1)
7311 return BTRFS_RAID_RAID1;
7312 else if (flags & BTRFS_BLOCK_GROUP_DUP)
7313 return BTRFS_RAID_DUP;
7314 else if (flags & BTRFS_BLOCK_GROUP_RAID0)
7315 return BTRFS_RAID_RAID0;
7316 else if (flags & BTRFS_BLOCK_GROUP_RAID5)
7317 return BTRFS_RAID_RAID5;
7318 else if (flags & BTRFS_BLOCK_GROUP_RAID6)
7319 return BTRFS_RAID_RAID6;
7320
7321 return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
7322 }
7323
7324 int get_block_group_index(struct btrfs_block_group_cache *cache)
7325 {
7326 return __get_raid_index(cache->flags);
7327 }
7328
7329 static const char *btrfs_raid_type_names[BTRFS_NR_RAID_TYPES] = {
7330 [BTRFS_RAID_RAID10] = "raid10",
7331 [BTRFS_RAID_RAID1] = "raid1",
7332 [BTRFS_RAID_DUP] = "dup",
7333 [BTRFS_RAID_RAID0] = "raid0",
7334 [BTRFS_RAID_SINGLE] = "single",
7335 [BTRFS_RAID_RAID5] = "raid5",
7336 [BTRFS_RAID_RAID6] = "raid6",
7337 };
7338
7339 static const char *get_raid_name(enum btrfs_raid_types type)
7340 {
7341 if (type >= BTRFS_NR_RAID_TYPES)
7342 return NULL;
7343
7344 return btrfs_raid_type_names[type];
7345 }
7346
7347 enum btrfs_loop_type {
7348 LOOP_CACHING_NOWAIT = 0,
7349 LOOP_CACHING_WAIT = 1,
7350 LOOP_ALLOC_CHUNK = 2,
7351 LOOP_NO_EMPTY_SIZE = 3,
7352 };
7353
7354 static inline void
7355 btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
7356 int delalloc)
7357 {
7358 if (delalloc)
7359 down_read(&cache->data_rwsem);
7360 }
7361
7362 static inline void
7363 btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
7364 int delalloc)
7365 {
7366 btrfs_get_block_group(cache);
7367 if (delalloc)
7368 down_read(&cache->data_rwsem);
7369 }
7370
7371 static struct btrfs_block_group_cache *
7372 btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
7373 struct btrfs_free_cluster *cluster,
7374 int delalloc)
7375 {
7376 struct btrfs_block_group_cache *used_bg = NULL;
7377
7378 spin_lock(&cluster->refill_lock);
7379 while (1) {
7380 used_bg = cluster->block_group;
7381 if (!used_bg)
7382 return NULL;
7383
7384 if (used_bg == block_group)
7385 return used_bg;
7386
7387 btrfs_get_block_group(used_bg);
7388
7389 if (!delalloc)
7390 return used_bg;
7391
7392 if (down_read_trylock(&used_bg->data_rwsem))
7393 return used_bg;
7394
7395 spin_unlock(&cluster->refill_lock);
7396
7397 down_read(&used_bg->data_rwsem);
7398
7399 spin_lock(&cluster->refill_lock);
7400 if (used_bg == cluster->block_group)
7401 return used_bg;
7402
7403 up_read(&used_bg->data_rwsem);
7404 btrfs_put_block_group(used_bg);
7405 }
7406 }
7407
7408 static inline void
7409 btrfs_release_block_group(struct btrfs_block_group_cache *cache,
7410 int delalloc)
7411 {
7412 if (delalloc)
7413 up_read(&cache->data_rwsem);
7414 btrfs_put_block_group(cache);
7415 }
7416
7417 /*
7418 * walks the btree of allocated extents and find a hole of a given size.
7419 * The key ins is changed to record the hole:
7420 * ins->objectid == start position
7421 * ins->flags = BTRFS_EXTENT_ITEM_KEY
7422 * ins->offset == the size of the hole.
7423 * Any available blocks before search_start are skipped.
7424 *
7425 * If there is no suitable free space, we will record the max size of
7426 * the free space extent currently.
7427 */
7428 static noinline int find_free_extent(struct btrfs_root *orig_root,
7429 u64 ram_bytes, u64 num_bytes, u64 empty_size,
7430 u64 hint_byte, struct btrfs_key *ins,
7431 u64 flags, int delalloc)
7432 {
7433 int ret = 0;
7434 struct btrfs_root *root = orig_root->fs_info->extent_root;
7435 struct btrfs_free_cluster *last_ptr = NULL;
7436 struct btrfs_block_group_cache *block_group = NULL;
7437 u64 search_start = 0;
7438 u64 max_extent_size = 0;
7439 u64 empty_cluster = 0;
7440 struct btrfs_space_info *space_info;
7441 int loop = 0;
7442 int index = __get_raid_index(flags);
7443 bool failed_cluster_refill = false;
7444 bool failed_alloc = false;
7445 bool use_cluster = true;
7446 bool have_caching_bg = false;
7447 bool orig_have_caching_bg = false;
7448 bool full_search = false;
7449
7450 WARN_ON(num_bytes < root->sectorsize);
7451 ins->type = BTRFS_EXTENT_ITEM_KEY;
7452 ins->objectid = 0;
7453 ins->offset = 0;
7454
7455 trace_find_free_extent(orig_root, num_bytes, empty_size, flags);
7456
7457 space_info = __find_space_info(root->fs_info, flags);
7458 if (!space_info) {
7459 btrfs_err(root->fs_info, "No space info for %llu", flags);
7460 return -ENOSPC;
7461 }
7462
7463 /*
7464 * If our free space is heavily fragmented we may not be able to make
7465 * big contiguous allocations, so instead of doing the expensive search
7466 * for free space, simply return ENOSPC with our max_extent_size so we
7467 * can go ahead and search for a more manageable chunk.
7468 *
7469 * If our max_extent_size is large enough for our allocation simply
7470 * disable clustering since we will likely not be able to find enough
7471 * space to create a cluster and induce latency trying.
7472 */
7473 if (unlikely(space_info->max_extent_size)) {
7474 spin_lock(&space_info->lock);
7475 if (space_info->max_extent_size &&
7476 num_bytes > space_info->max_extent_size) {
7477 ins->offset = space_info->max_extent_size;
7478 spin_unlock(&space_info->lock);
7479 return -ENOSPC;
7480 } else if (space_info->max_extent_size) {
7481 use_cluster = false;
7482 }
7483 spin_unlock(&space_info->lock);
7484 }
7485
7486 last_ptr = fetch_cluster_info(orig_root, space_info, &empty_cluster);
7487 if (last_ptr) {
7488 spin_lock(&last_ptr->lock);
7489 if (last_ptr->block_group)
7490 hint_byte = last_ptr->window_start;
7491 if (last_ptr->fragmented) {
7492 /*
7493 * We still set window_start so we can keep track of the
7494 * last place we found an allocation to try and save
7495 * some time.
7496 */
7497 hint_byte = last_ptr->window_start;
7498 use_cluster = false;
7499 }
7500 spin_unlock(&last_ptr->lock);
7501 }
7502
7503 search_start = max(search_start, first_logical_byte(root, 0));
7504 search_start = max(search_start, hint_byte);
7505 if (search_start == hint_byte) {
7506 block_group = btrfs_lookup_block_group(root->fs_info,
7507 search_start);
7508 /*
7509 * we don't want to use the block group if it doesn't match our
7510 * allocation bits, or if its not cached.
7511 *
7512 * However if we are re-searching with an ideal block group
7513 * picked out then we don't care that the block group is cached.
7514 */
7515 if (block_group && block_group_bits(block_group, flags) &&
7516 block_group->cached != BTRFS_CACHE_NO) {
7517 down_read(&space_info->groups_sem);
7518 if (list_empty(&block_group->list) ||
7519 block_group->ro) {
7520 /*
7521 * someone is removing this block group,
7522 * we can't jump into the have_block_group
7523 * target because our list pointers are not
7524 * valid
7525 */
7526 btrfs_put_block_group(block_group);
7527 up_read(&space_info->groups_sem);
7528 } else {
7529 index = get_block_group_index(block_group);
7530 btrfs_lock_block_group(block_group, delalloc);
7531 goto have_block_group;
7532 }
7533 } else if (block_group) {
7534 btrfs_put_block_group(block_group);
7535 }
7536 }
7537 search:
7538 have_caching_bg = false;
7539 if (index == 0 || index == __get_raid_index(flags))
7540 full_search = true;
7541 down_read(&space_info->groups_sem);
7542 list_for_each_entry(block_group, &space_info->block_groups[index],
7543 list) {
7544 u64 offset;
7545 int cached;
7546
7547 btrfs_grab_block_group(block_group, delalloc);
7548 search_start = block_group->key.objectid;
7549
7550 /*
7551 * this can happen if we end up cycling through all the
7552 * raid types, but we want to make sure we only allocate
7553 * for the proper type.
7554 */
7555 if (!block_group_bits(block_group, flags)) {
7556 u64 extra = BTRFS_BLOCK_GROUP_DUP |
7557 BTRFS_BLOCK_GROUP_RAID1 |
7558 BTRFS_BLOCK_GROUP_RAID5 |
7559 BTRFS_BLOCK_GROUP_RAID6 |
7560 BTRFS_BLOCK_GROUP_RAID10;
7561
7562 /*
7563 * if they asked for extra copies and this block group
7564 * doesn't provide them, bail. This does allow us to
7565 * fill raid0 from raid1.
7566 */
7567 if ((flags & extra) && !(block_group->flags & extra))
7568 goto loop;
7569 }
7570
7571 have_block_group:
7572 cached = block_group_cache_done(block_group);
7573 if (unlikely(!cached)) {
7574 have_caching_bg = true;
7575 ret = cache_block_group(block_group, 0);
7576 BUG_ON(ret < 0);
7577 ret = 0;
7578 }
7579
7580 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
7581 goto loop;
7582 if (unlikely(block_group->ro))
7583 goto loop;
7584
7585 /*
7586 * Ok we want to try and use the cluster allocator, so
7587 * lets look there
7588 */
7589 if (last_ptr && use_cluster) {
7590 struct btrfs_block_group_cache *used_block_group;
7591 unsigned long aligned_cluster;
7592 /*
7593 * the refill lock keeps out other
7594 * people trying to start a new cluster
7595 */
7596 used_block_group = btrfs_lock_cluster(block_group,
7597 last_ptr,
7598 delalloc);
7599 if (!used_block_group)
7600 goto refill_cluster;
7601
7602 if (used_block_group != block_group &&
7603 (used_block_group->ro ||
7604 !block_group_bits(used_block_group, flags)))
7605 goto release_cluster;
7606
7607 offset = btrfs_alloc_from_cluster(used_block_group,
7608 last_ptr,
7609 num_bytes,
7610 used_block_group->key.objectid,
7611 &max_extent_size);
7612 if (offset) {
7613 /* we have a block, we're done */
7614 spin_unlock(&last_ptr->refill_lock);
7615 trace_btrfs_reserve_extent_cluster(root,
7616 used_block_group,
7617 search_start, num_bytes);
7618 if (used_block_group != block_group) {
7619 btrfs_release_block_group(block_group,
7620 delalloc);
7621 block_group = used_block_group;
7622 }
7623 goto checks;
7624 }
7625
7626 WARN_ON(last_ptr->block_group != used_block_group);
7627 release_cluster:
7628 /* If we are on LOOP_NO_EMPTY_SIZE, we can't
7629 * set up a new clusters, so lets just skip it
7630 * and let the allocator find whatever block
7631 * it can find. If we reach this point, we
7632 * will have tried the cluster allocator
7633 * plenty of times and not have found
7634 * anything, so we are likely way too
7635 * fragmented for the clustering stuff to find
7636 * anything.
7637 *
7638 * However, if the cluster is taken from the
7639 * current block group, release the cluster
7640 * first, so that we stand a better chance of
7641 * succeeding in the unclustered
7642 * allocation. */
7643 if (loop >= LOOP_NO_EMPTY_SIZE &&
7644 used_block_group != block_group) {
7645 spin_unlock(&last_ptr->refill_lock);
7646 btrfs_release_block_group(used_block_group,
7647 delalloc);
7648 goto unclustered_alloc;
7649 }
7650
7651 /*
7652 * this cluster didn't work out, free it and
7653 * start over
7654 */
7655 btrfs_return_cluster_to_free_space(NULL, last_ptr);
7656
7657 if (used_block_group != block_group)
7658 btrfs_release_block_group(used_block_group,
7659 delalloc);
7660 refill_cluster:
7661 if (loop >= LOOP_NO_EMPTY_SIZE) {
7662 spin_unlock(&last_ptr->refill_lock);
7663 goto unclustered_alloc;
7664 }
7665
7666 aligned_cluster = max_t(unsigned long,
7667 empty_cluster + empty_size,
7668 block_group->full_stripe_len);
7669
7670 /* allocate a cluster in this block group */
7671 ret = btrfs_find_space_cluster(root, block_group,
7672 last_ptr, search_start,
7673 num_bytes,
7674 aligned_cluster);
7675 if (ret == 0) {
7676 /*
7677 * now pull our allocation out of this
7678 * cluster
7679 */
7680 offset = btrfs_alloc_from_cluster(block_group,
7681 last_ptr,
7682 num_bytes,
7683 search_start,
7684 &max_extent_size);
7685 if (offset) {
7686 /* we found one, proceed */
7687 spin_unlock(&last_ptr->refill_lock);
7688 trace_btrfs_reserve_extent_cluster(root,
7689 block_group, search_start,
7690 num_bytes);
7691 goto checks;
7692 }
7693 } else if (!cached && loop > LOOP_CACHING_NOWAIT
7694 && !failed_cluster_refill) {
7695 spin_unlock(&last_ptr->refill_lock);
7696
7697 failed_cluster_refill = true;
7698 wait_block_group_cache_progress(block_group,
7699 num_bytes + empty_cluster + empty_size);
7700 goto have_block_group;
7701 }
7702
7703 /*
7704 * at this point we either didn't find a cluster
7705 * or we weren't able to allocate a block from our
7706 * cluster. Free the cluster we've been trying
7707 * to use, and go to the next block group
7708 */
7709 btrfs_return_cluster_to_free_space(NULL, last_ptr);
7710 spin_unlock(&last_ptr->refill_lock);
7711 goto loop;
7712 }
7713
7714 unclustered_alloc:
7715 /*
7716 * We are doing an unclustered alloc, set the fragmented flag so
7717 * we don't bother trying to setup a cluster again until we get
7718 * more space.
7719 */
7720 if (unlikely(last_ptr)) {
7721 spin_lock(&last_ptr->lock);
7722 last_ptr->fragmented = 1;
7723 spin_unlock(&last_ptr->lock);
7724 }
7725 spin_lock(&block_group->free_space_ctl->tree_lock);
7726 if (cached &&
7727 block_group->free_space_ctl->free_space <
7728 num_bytes + empty_cluster + empty_size) {
7729 if (block_group->free_space_ctl->free_space >
7730 max_extent_size)
7731 max_extent_size =
7732 block_group->free_space_ctl->free_space;
7733 spin_unlock(&block_group->free_space_ctl->tree_lock);
7734 goto loop;
7735 }
7736 spin_unlock(&block_group->free_space_ctl->tree_lock);
7737
7738 offset = btrfs_find_space_for_alloc(block_group, search_start,
7739 num_bytes, empty_size,
7740 &max_extent_size);
7741 /*
7742 * If we didn't find a chunk, and we haven't failed on this
7743 * block group before, and this block group is in the middle of
7744 * caching and we are ok with waiting, then go ahead and wait
7745 * for progress to be made, and set failed_alloc to true.
7746 *
7747 * If failed_alloc is true then we've already waited on this
7748 * block group once and should move on to the next block group.
7749 */
7750 if (!offset && !failed_alloc && !cached &&
7751 loop > LOOP_CACHING_NOWAIT) {
7752 wait_block_group_cache_progress(block_group,
7753 num_bytes + empty_size);
7754 failed_alloc = true;
7755 goto have_block_group;
7756 } else if (!offset) {
7757 goto loop;
7758 }
7759 checks:
7760 search_start = ALIGN(offset, root->stripesize);
7761
7762 /* move on to the next group */
7763 if (search_start + num_bytes >
7764 block_group->key.objectid + block_group->key.offset) {
7765 btrfs_add_free_space(block_group, offset, num_bytes);
7766 goto loop;
7767 }
7768
7769 if (offset < search_start)
7770 btrfs_add_free_space(block_group, offset,
7771 search_start - offset);
7772 BUG_ON(offset > search_start);
7773
7774 ret = btrfs_add_reserved_bytes(block_group, ram_bytes,
7775 num_bytes, delalloc);
7776 if (ret == -EAGAIN) {
7777 btrfs_add_free_space(block_group, offset, num_bytes);
7778 goto loop;
7779 }
7780 btrfs_inc_block_group_reservations(block_group);
7781
7782 /* we are all good, lets return */
7783 ins->objectid = search_start;
7784 ins->offset = num_bytes;
7785
7786 trace_btrfs_reserve_extent(orig_root, block_group,
7787 search_start, num_bytes);
7788 btrfs_release_block_group(block_group, delalloc);
7789 break;
7790 loop:
7791 failed_cluster_refill = false;
7792 failed_alloc = false;
7793 BUG_ON(index != get_block_group_index(block_group));
7794 btrfs_release_block_group(block_group, delalloc);
7795 }
7796 up_read(&space_info->groups_sem);
7797
7798 if ((loop == LOOP_CACHING_NOWAIT) && have_caching_bg
7799 && !orig_have_caching_bg)
7800 orig_have_caching_bg = true;
7801
7802 if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
7803 goto search;
7804
7805 if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
7806 goto search;
7807
7808 /*
7809 * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
7810 * caching kthreads as we move along
7811 * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
7812 * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
7813 * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
7814 * again
7815 */
7816 if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
7817 index = 0;
7818 if (loop == LOOP_CACHING_NOWAIT) {
7819 /*
7820 * We want to skip the LOOP_CACHING_WAIT step if we
7821 * don't have any uncached bgs and we've already done a
7822 * full search through.
7823 */
7824 if (orig_have_caching_bg || !full_search)
7825 loop = LOOP_CACHING_WAIT;
7826 else
7827 loop = LOOP_ALLOC_CHUNK;
7828 } else {
7829 loop++;
7830 }
7831
7832 if (loop == LOOP_ALLOC_CHUNK) {
7833 struct btrfs_trans_handle *trans;
7834 int exist = 0;
7835
7836 trans = current->journal_info;
7837 if (trans)
7838 exist = 1;
7839 else
7840 trans = btrfs_join_transaction(root);
7841
7842 if (IS_ERR(trans)) {
7843 ret = PTR_ERR(trans);
7844 goto out;
7845 }
7846
7847 ret = do_chunk_alloc(trans, root, flags,
7848 CHUNK_ALLOC_FORCE);
7849
7850 /*
7851 * If we can't allocate a new chunk we've already looped
7852 * through at least once, move on to the NO_EMPTY_SIZE
7853 * case.
7854 */
7855 if (ret == -ENOSPC)
7856 loop = LOOP_NO_EMPTY_SIZE;
7857
7858 /*
7859 * Do not bail out on ENOSPC since we
7860 * can do more things.
7861 */
7862 if (ret < 0 && ret != -ENOSPC)
7863 btrfs_abort_transaction(trans, ret);
7864 else
7865 ret = 0;
7866 if (!exist)
7867 btrfs_end_transaction(trans, root);
7868 if (ret)
7869 goto out;
7870 }
7871
7872 if (loop == LOOP_NO_EMPTY_SIZE) {
7873 /*
7874 * Don't loop again if we already have no empty_size and
7875 * no empty_cluster.
7876 */
7877 if (empty_size == 0 &&
7878 empty_cluster == 0) {
7879 ret = -ENOSPC;
7880 goto out;
7881 }
7882 empty_size = 0;
7883 empty_cluster = 0;
7884 }
7885
7886 goto search;
7887 } else if (!ins->objectid) {
7888 ret = -ENOSPC;
7889 } else if (ins->objectid) {
7890 if (!use_cluster && last_ptr) {
7891 spin_lock(&last_ptr->lock);
7892 last_ptr->window_start = ins->objectid;
7893 spin_unlock(&last_ptr->lock);
7894 }
7895 ret = 0;
7896 }
7897 out:
7898 if (ret == -ENOSPC) {
7899 spin_lock(&space_info->lock);
7900 space_info->max_extent_size = max_extent_size;
7901 spin_unlock(&space_info->lock);
7902 ins->offset = max_extent_size;
7903 }
7904 return ret;
7905 }
7906
7907 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
7908 int dump_block_groups)
7909 {
7910 struct btrfs_block_group_cache *cache;
7911 int index = 0;
7912
7913 spin_lock(&info->lock);
7914 printk(KERN_INFO "BTRFS: space_info %llu has %llu free, is %sfull\n",
7915 info->flags,
7916 info->total_bytes - info->bytes_used - info->bytes_pinned -
7917 info->bytes_reserved - info->bytes_readonly -
7918 info->bytes_may_use, (info->full) ? "" : "not ");
7919 printk(KERN_INFO "BTRFS: space_info total=%llu, used=%llu, pinned=%llu, "
7920 "reserved=%llu, may_use=%llu, readonly=%llu\n",
7921 info->total_bytes, info->bytes_used, info->bytes_pinned,
7922 info->bytes_reserved, info->bytes_may_use,
7923 info->bytes_readonly);
7924 spin_unlock(&info->lock);
7925
7926 if (!dump_block_groups)
7927 return;
7928
7929 down_read(&info->groups_sem);
7930 again:
7931 list_for_each_entry(cache, &info->block_groups[index], list) {
7932 spin_lock(&cache->lock);
7933 printk(KERN_INFO "BTRFS: "
7934 "block group %llu has %llu bytes, "
7935 "%llu used %llu pinned %llu reserved %s\n",
7936 cache->key.objectid, cache->key.offset,
7937 btrfs_block_group_used(&cache->item), cache->pinned,
7938 cache->reserved, cache->ro ? "[readonly]" : "");
7939 btrfs_dump_free_space(cache, bytes);
7940 spin_unlock(&cache->lock);
7941 }
7942 if (++index < BTRFS_NR_RAID_TYPES)
7943 goto again;
7944 up_read(&info->groups_sem);
7945 }
7946
7947 int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes,
7948 u64 num_bytes, u64 min_alloc_size,
7949 u64 empty_size, u64 hint_byte,
7950 struct btrfs_key *ins, int is_data, int delalloc)
7951 {
7952 bool final_tried = num_bytes == min_alloc_size;
7953 u64 flags;
7954 int ret;
7955
7956 flags = btrfs_get_alloc_profile(root, is_data);
7957 again:
7958 WARN_ON(num_bytes < root->sectorsize);
7959 ret = find_free_extent(root, ram_bytes, num_bytes, empty_size,
7960 hint_byte, ins, flags, delalloc);
7961 if (!ret && !is_data) {
7962 btrfs_dec_block_group_reservations(root->fs_info,
7963 ins->objectid);
7964 } else if (ret == -ENOSPC) {
7965 if (!final_tried && ins->offset) {
7966 num_bytes = min(num_bytes >> 1, ins->offset);
7967 num_bytes = round_down(num_bytes, root->sectorsize);
7968 num_bytes = max(num_bytes, min_alloc_size);
7969 ram_bytes = num_bytes;
7970 if (num_bytes == min_alloc_size)
7971 final_tried = true;
7972 goto again;
7973 } else if (btrfs_test_opt(root->fs_info, ENOSPC_DEBUG)) {
7974 struct btrfs_space_info *sinfo;
7975
7976 sinfo = __find_space_info(root->fs_info, flags);
7977 btrfs_err(root->fs_info, "allocation failed flags %llu, wanted %llu",
7978 flags, num_bytes);
7979 if (sinfo)
7980 dump_space_info(sinfo, num_bytes, 1);
7981 }
7982 }
7983
7984 return ret;
7985 }
7986
7987 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
7988 u64 start, u64 len,
7989 int pin, int delalloc)
7990 {
7991 struct btrfs_block_group_cache *cache;
7992 int ret = 0;
7993
7994 cache = btrfs_lookup_block_group(root->fs_info, start);
7995 if (!cache) {
7996 btrfs_err(root->fs_info, "Unable to find block group for %llu",
7997 start);
7998 return -ENOSPC;
7999 }
8000
8001 if (pin)
8002 pin_down_extent(root, cache, start, len, 1);
8003 else {
8004 if (btrfs_test_opt(root->fs_info, DISCARD))
8005 ret = btrfs_discard_extent(root, start, len, NULL);
8006 btrfs_add_free_space(cache, start, len);
8007 btrfs_free_reserved_bytes(cache, len, delalloc);
8008 trace_btrfs_reserved_extent_free(root, start, len);
8009 }
8010
8011 btrfs_put_block_group(cache);
8012 return ret;
8013 }
8014
8015 int btrfs_free_reserved_extent(struct btrfs_root *root,
8016 u64 start, u64 len, int delalloc)
8017 {
8018 return __btrfs_free_reserved_extent(root, start, len, 0, delalloc);
8019 }
8020
8021 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
8022 u64 start, u64 len)
8023 {
8024 return __btrfs_free_reserved_extent(root, start, len, 1, 0);
8025 }
8026
8027 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8028 struct btrfs_root *root,
8029 u64 parent, u64 root_objectid,
8030 u64 flags, u64 owner, u64 offset,
8031 struct btrfs_key *ins, int ref_mod)
8032 {
8033 int ret;
8034 struct btrfs_fs_info *fs_info = root->fs_info;
8035 struct btrfs_extent_item *extent_item;
8036 struct btrfs_extent_inline_ref *iref;
8037 struct btrfs_path *path;
8038 struct extent_buffer *leaf;
8039 int type;
8040 u32 size;
8041
8042 if (parent > 0)
8043 type = BTRFS_SHARED_DATA_REF_KEY;
8044 else
8045 type = BTRFS_EXTENT_DATA_REF_KEY;
8046
8047 size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
8048
8049 path = btrfs_alloc_path();
8050 if (!path)
8051 return -ENOMEM;
8052
8053 path->leave_spinning = 1;
8054 ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
8055 ins, size);
8056 if (ret) {
8057 btrfs_free_path(path);
8058 return ret;
8059 }
8060
8061 leaf = path->nodes[0];
8062 extent_item = btrfs_item_ptr(leaf, path->slots[0],
8063 struct btrfs_extent_item);
8064 btrfs_set_extent_refs(leaf, extent_item, ref_mod);
8065 btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8066 btrfs_set_extent_flags(leaf, extent_item,
8067 flags | BTRFS_EXTENT_FLAG_DATA);
8068
8069 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8070 btrfs_set_extent_inline_ref_type(leaf, iref, type);
8071 if (parent > 0) {
8072 struct btrfs_shared_data_ref *ref;
8073 ref = (struct btrfs_shared_data_ref *)(iref + 1);
8074 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
8075 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
8076 } else {
8077 struct btrfs_extent_data_ref *ref;
8078 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
8079 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
8080 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
8081 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
8082 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
8083 }
8084
8085 btrfs_mark_buffer_dirty(path->nodes[0]);
8086 btrfs_free_path(path);
8087
8088 ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
8089 ins->offset);
8090 if (ret)
8091 return ret;
8092
8093 ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
8094 if (ret) { /* -ENOENT, logic error */
8095 btrfs_err(fs_info, "update block group failed for %llu %llu",
8096 ins->objectid, ins->offset);
8097 BUG();
8098 }
8099 trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
8100 return ret;
8101 }
8102
8103 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
8104 struct btrfs_root *root,
8105 u64 parent, u64 root_objectid,
8106 u64 flags, struct btrfs_disk_key *key,
8107 int level, struct btrfs_key *ins)
8108 {
8109 int ret;
8110 struct btrfs_fs_info *fs_info = root->fs_info;
8111 struct btrfs_extent_item *extent_item;
8112 struct btrfs_tree_block_info *block_info;
8113 struct btrfs_extent_inline_ref *iref;
8114 struct btrfs_path *path;
8115 struct extent_buffer *leaf;
8116 u32 size = sizeof(*extent_item) + sizeof(*iref);
8117 u64 num_bytes = ins->offset;
8118 bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
8119 SKINNY_METADATA);
8120
8121 if (!skinny_metadata)
8122 size += sizeof(*block_info);
8123
8124 path = btrfs_alloc_path();
8125 if (!path) {
8126 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
8127 root->nodesize);
8128 return -ENOMEM;
8129 }
8130
8131 path->leave_spinning = 1;
8132 ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
8133 ins, size);
8134 if (ret) {
8135 btrfs_free_path(path);
8136 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
8137 root->nodesize);
8138 return ret;
8139 }
8140
8141 leaf = path->nodes[0];
8142 extent_item = btrfs_item_ptr(leaf, path->slots[0],
8143 struct btrfs_extent_item);
8144 btrfs_set_extent_refs(leaf, extent_item, 1);
8145 btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8146 btrfs_set_extent_flags(leaf, extent_item,
8147 flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
8148
8149 if (skinny_metadata) {
8150 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8151 num_bytes = root->nodesize;
8152 } else {
8153 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
8154 btrfs_set_tree_block_key(leaf, block_info, key);
8155 btrfs_set_tree_block_level(leaf, block_info, level);
8156 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
8157 }
8158
8159 if (parent > 0) {
8160 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
8161 btrfs_set_extent_inline_ref_type(leaf, iref,
8162 BTRFS_SHARED_BLOCK_REF_KEY);
8163 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
8164 } else {
8165 btrfs_set_extent_inline_ref_type(leaf, iref,
8166 BTRFS_TREE_BLOCK_REF_KEY);
8167 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
8168 }
8169
8170 btrfs_mark_buffer_dirty(leaf);
8171 btrfs_free_path(path);
8172
8173 ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
8174 num_bytes);
8175 if (ret)
8176 return ret;
8177
8178 ret = update_block_group(trans, root, ins->objectid, root->nodesize,
8179 1);
8180 if (ret) { /* -ENOENT, logic error */
8181 btrfs_err(fs_info, "update block group failed for %llu %llu",
8182 ins->objectid, ins->offset);
8183 BUG();
8184 }
8185
8186 trace_btrfs_reserved_extent_alloc(root, ins->objectid, root->nodesize);
8187 return ret;
8188 }
8189
8190 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8191 struct btrfs_root *root,
8192 u64 root_objectid, u64 owner,
8193 u64 offset, u64 ram_bytes,
8194 struct btrfs_key *ins)
8195 {
8196 int ret;
8197
8198 BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
8199
8200 ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
8201 ins->offset, 0,
8202 root_objectid, owner, offset,
8203 ram_bytes, BTRFS_ADD_DELAYED_EXTENT,
8204 NULL);
8205 return ret;
8206 }
8207
8208 /*
8209 * this is used by the tree logging recovery code. It records that
8210 * an extent has been allocated and makes sure to clear the free
8211 * space cache bits as well
8212 */
8213 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
8214 struct btrfs_root *root,
8215 u64 root_objectid, u64 owner, u64 offset,
8216 struct btrfs_key *ins)
8217 {
8218 int ret;
8219 struct btrfs_block_group_cache *block_group;
8220 struct btrfs_space_info *space_info;
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 space_info = block_group->space_info;
8237 spin_lock(&space_info->lock);
8238 spin_lock(&block_group->lock);
8239 space_info->bytes_reserved += ins->offset;
8240 block_group->reserved += ins->offset;
8241 spin_unlock(&block_group->lock);
8242 spin_unlock(&space_info->lock);
8243
8244 ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
8245 0, owner, offset, ins, 1);
8246 btrfs_put_block_group(block_group);
8247 return ret;
8248 }
8249
8250 static struct extent_buffer *
8251 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
8252 u64 bytenr, int level)
8253 {
8254 struct extent_buffer *buf;
8255
8256 buf = btrfs_find_create_tree_block(root, bytenr);
8257 if (IS_ERR(buf))
8258 return buf;
8259
8260 btrfs_set_header_generation(buf, trans->transid);
8261 btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
8262 btrfs_tree_lock(buf);
8263 clean_tree_block(trans, root->fs_info, buf);
8264 clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
8265
8266 btrfs_set_lock_blocking(buf);
8267 set_extent_buffer_uptodate(buf);
8268
8269 if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
8270 buf->log_index = root->log_transid % 2;
8271 /*
8272 * we allow two log transactions at a time, use different
8273 * EXENT bit to differentiate dirty pages.
8274 */
8275 if (buf->log_index == 0)
8276 set_extent_dirty(&root->dirty_log_pages, buf->start,
8277 buf->start + buf->len - 1, GFP_NOFS);
8278 else
8279 set_extent_new(&root->dirty_log_pages, buf->start,
8280 buf->start + buf->len - 1);
8281 } else {
8282 buf->log_index = -1;
8283 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
8284 buf->start + buf->len - 1, GFP_NOFS);
8285 }
8286 trans->dirty = true;
8287 /* this returns a buffer locked for blocking */
8288 return buf;
8289 }
8290
8291 static struct btrfs_block_rsv *
8292 use_block_rsv(struct btrfs_trans_handle *trans,
8293 struct btrfs_root *root, u32 blocksize)
8294 {
8295 struct btrfs_block_rsv *block_rsv;
8296 struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
8297 int ret;
8298 bool global_updated = false;
8299
8300 block_rsv = get_block_rsv(trans, root);
8301
8302 if (unlikely(block_rsv->size == 0))
8303 goto try_reserve;
8304 again:
8305 ret = block_rsv_use_bytes(block_rsv, blocksize);
8306 if (!ret)
8307 return block_rsv;
8308
8309 if (block_rsv->failfast)
8310 return ERR_PTR(ret);
8311
8312 if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
8313 global_updated = true;
8314 update_global_block_rsv(root->fs_info);
8315 goto again;
8316 }
8317
8318 if (btrfs_test_opt(root->fs_info, ENOSPC_DEBUG)) {
8319 static DEFINE_RATELIMIT_STATE(_rs,
8320 DEFAULT_RATELIMIT_INTERVAL * 10,
8321 /*DEFAULT_RATELIMIT_BURST*/ 1);
8322 if (__ratelimit(&_rs))
8323 WARN(1, KERN_DEBUG
8324 "BTRFS: block rsv returned %d\n", ret);
8325 }
8326 try_reserve:
8327 ret = reserve_metadata_bytes(root, block_rsv, blocksize,
8328 BTRFS_RESERVE_NO_FLUSH);
8329 if (!ret)
8330 return block_rsv;
8331 /*
8332 * If we couldn't reserve metadata bytes try and use some from
8333 * the global reserve if its space type is the same as the global
8334 * reservation.
8335 */
8336 if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
8337 block_rsv->space_info == global_rsv->space_info) {
8338 ret = block_rsv_use_bytes(global_rsv, blocksize);
8339 if (!ret)
8340 return global_rsv;
8341 }
8342 return ERR_PTR(ret);
8343 }
8344
8345 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
8346 struct btrfs_block_rsv *block_rsv, u32 blocksize)
8347 {
8348 block_rsv_add_bytes(block_rsv, blocksize, 0);
8349 block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
8350 }
8351
8352 /*
8353 * finds a free extent and does all the dirty work required for allocation
8354 * returns the tree buffer or an ERR_PTR on error.
8355 */
8356 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
8357 struct btrfs_root *root,
8358 u64 parent, u64 root_objectid,
8359 struct btrfs_disk_key *key, int level,
8360 u64 hint, u64 empty_size)
8361 {
8362 struct btrfs_key ins;
8363 struct btrfs_block_rsv *block_rsv;
8364 struct extent_buffer *buf;
8365 struct btrfs_delayed_extent_op *extent_op;
8366 u64 flags = 0;
8367 int ret;
8368 u32 blocksize = root->nodesize;
8369 bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
8370 SKINNY_METADATA);
8371
8372 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
8373 if (btrfs_is_testing(root->fs_info)) {
8374 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
8375 level);
8376 if (!IS_ERR(buf))
8377 root->alloc_bytenr += blocksize;
8378 return buf;
8379 }
8380 #endif
8381
8382 block_rsv = use_block_rsv(trans, root, blocksize);
8383 if (IS_ERR(block_rsv))
8384 return ERR_CAST(block_rsv);
8385
8386 ret = btrfs_reserve_extent(root, blocksize, blocksize, blocksize,
8387 empty_size, hint, &ins, 0, 0);
8388 if (ret)
8389 goto out_unuse;
8390
8391 buf = btrfs_init_new_buffer(trans, root, ins.objectid, level);
8392 if (IS_ERR(buf)) {
8393 ret = PTR_ERR(buf);
8394 goto out_free_reserved;
8395 }
8396
8397 if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
8398 if (parent == 0)
8399 parent = ins.objectid;
8400 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
8401 } else
8402 BUG_ON(parent > 0);
8403
8404 if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
8405 extent_op = btrfs_alloc_delayed_extent_op();
8406 if (!extent_op) {
8407 ret = -ENOMEM;
8408 goto out_free_buf;
8409 }
8410 if (key)
8411 memcpy(&extent_op->key, key, sizeof(extent_op->key));
8412 else
8413 memset(&extent_op->key, 0, sizeof(extent_op->key));
8414 extent_op->flags_to_set = flags;
8415 extent_op->update_key = skinny_metadata ? false : true;
8416 extent_op->update_flags = true;
8417 extent_op->is_data = false;
8418 extent_op->level = level;
8419
8420 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
8421 ins.objectid, ins.offset,
8422 parent, root_objectid, level,
8423 BTRFS_ADD_DELAYED_EXTENT,
8424 extent_op);
8425 if (ret)
8426 goto out_free_delayed;
8427 }
8428 return buf;
8429
8430 out_free_delayed:
8431 btrfs_free_delayed_extent_op(extent_op);
8432 out_free_buf:
8433 free_extent_buffer(buf);
8434 out_free_reserved:
8435 btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 0);
8436 out_unuse:
8437 unuse_block_rsv(root->fs_info, block_rsv, blocksize);
8438 return ERR_PTR(ret);
8439 }
8440
8441 struct walk_control {
8442 u64 refs[BTRFS_MAX_LEVEL];
8443 u64 flags[BTRFS_MAX_LEVEL];
8444 struct btrfs_key update_progress;
8445 int stage;
8446 int level;
8447 int shared_level;
8448 int update_ref;
8449 int keep_locks;
8450 int reada_slot;
8451 int reada_count;
8452 int for_reloc;
8453 };
8454
8455 #define DROP_REFERENCE 1
8456 #define UPDATE_BACKREF 2
8457
8458 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
8459 struct btrfs_root *root,
8460 struct walk_control *wc,
8461 struct btrfs_path *path)
8462 {
8463 u64 bytenr;
8464 u64 generation;
8465 u64 refs;
8466 u64 flags;
8467 u32 nritems;
8468 u32 blocksize;
8469 struct btrfs_key key;
8470 struct extent_buffer *eb;
8471 int ret;
8472 int slot;
8473 int nread = 0;
8474
8475 if (path->slots[wc->level] < wc->reada_slot) {
8476 wc->reada_count = wc->reada_count * 2 / 3;
8477 wc->reada_count = max(wc->reada_count, 2);
8478 } else {
8479 wc->reada_count = wc->reada_count * 3 / 2;
8480 wc->reada_count = min_t(int, wc->reada_count,
8481 BTRFS_NODEPTRS_PER_BLOCK(root));
8482 }
8483
8484 eb = path->nodes[wc->level];
8485 nritems = btrfs_header_nritems(eb);
8486 blocksize = root->nodesize;
8487
8488 for (slot = path->slots[wc->level]; slot < nritems; slot++) {
8489 if (nread >= wc->reada_count)
8490 break;
8491
8492 cond_resched();
8493 bytenr = btrfs_node_blockptr(eb, slot);
8494 generation = btrfs_node_ptr_generation(eb, slot);
8495
8496 if (slot == path->slots[wc->level])
8497 goto reada;
8498
8499 if (wc->stage == UPDATE_BACKREF &&
8500 generation <= root->root_key.offset)
8501 continue;
8502
8503 /* We don't lock the tree block, it's OK to be racy here */
8504 ret = btrfs_lookup_extent_info(trans, root, bytenr,
8505 wc->level - 1, 1, &refs,
8506 &flags);
8507 /* We don't care about errors in readahead. */
8508 if (ret < 0)
8509 continue;
8510 BUG_ON(refs == 0);
8511
8512 if (wc->stage == DROP_REFERENCE) {
8513 if (refs == 1)
8514 goto reada;
8515
8516 if (wc->level == 1 &&
8517 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8518 continue;
8519 if (!wc->update_ref ||
8520 generation <= root->root_key.offset)
8521 continue;
8522 btrfs_node_key_to_cpu(eb, &key, slot);
8523 ret = btrfs_comp_cpu_keys(&key,
8524 &wc->update_progress);
8525 if (ret < 0)
8526 continue;
8527 } else {
8528 if (wc->level == 1 &&
8529 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8530 continue;
8531 }
8532 reada:
8533 readahead_tree_block(root, bytenr);
8534 nread++;
8535 }
8536 wc->reada_slot = slot;
8537 }
8538
8539 static int account_leaf_items(struct btrfs_trans_handle *trans,
8540 struct btrfs_root *root,
8541 struct extent_buffer *eb)
8542 {
8543 int nr = btrfs_header_nritems(eb);
8544 int i, extent_type, ret;
8545 struct btrfs_key key;
8546 struct btrfs_file_extent_item *fi;
8547 u64 bytenr, num_bytes;
8548
8549 /* We can be called directly from walk_up_proc() */
8550 if (!root->fs_info->quota_enabled)
8551 return 0;
8552
8553 for (i = 0; i < nr; i++) {
8554 btrfs_item_key_to_cpu(eb, &key, i);
8555
8556 if (key.type != BTRFS_EXTENT_DATA_KEY)
8557 continue;
8558
8559 fi = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
8560 /* filter out non qgroup-accountable extents */
8561 extent_type = btrfs_file_extent_type(eb, fi);
8562
8563 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
8564 continue;
8565
8566 bytenr = btrfs_file_extent_disk_bytenr(eb, fi);
8567 if (!bytenr)
8568 continue;
8569
8570 num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
8571
8572 ret = btrfs_qgroup_insert_dirty_extent(trans, root->fs_info,
8573 bytenr, num_bytes, GFP_NOFS);
8574 if (ret)
8575 return ret;
8576 }
8577 return 0;
8578 }
8579
8580 /*
8581 * Walk up the tree from the bottom, freeing leaves and any interior
8582 * nodes which have had all slots visited. If a node (leaf or
8583 * interior) is freed, the node above it will have it's slot
8584 * incremented. The root node will never be freed.
8585 *
8586 * At the end of this function, we should have a path which has all
8587 * slots incremented to the next position for a search. If we need to
8588 * read a new node it will be NULL and the node above it will have the
8589 * correct slot selected for a later read.
8590 *
8591 * If we increment the root nodes slot counter past the number of
8592 * elements, 1 is returned to signal completion of the search.
8593 */
8594 static int adjust_slots_upwards(struct btrfs_root *root,
8595 struct btrfs_path *path, int root_level)
8596 {
8597 int level = 0;
8598 int nr, slot;
8599 struct extent_buffer *eb;
8600
8601 if (root_level == 0)
8602 return 1;
8603
8604 while (level <= root_level) {
8605 eb = path->nodes[level];
8606 nr = btrfs_header_nritems(eb);
8607 path->slots[level]++;
8608 slot = path->slots[level];
8609 if (slot >= nr || level == 0) {
8610 /*
8611 * Don't free the root - we will detect this
8612 * condition after our loop and return a
8613 * positive value for caller to stop walking the tree.
8614 */
8615 if (level != root_level) {
8616 btrfs_tree_unlock_rw(eb, path->locks[level]);
8617 path->locks[level] = 0;
8618
8619 free_extent_buffer(eb);
8620 path->nodes[level] = NULL;
8621 path->slots[level] = 0;
8622 }
8623 } else {
8624 /*
8625 * We have a valid slot to walk back down
8626 * from. Stop here so caller can process these
8627 * new nodes.
8628 */
8629 break;
8630 }
8631
8632 level++;
8633 }
8634
8635 eb = path->nodes[root_level];
8636 if (path->slots[root_level] >= btrfs_header_nritems(eb))
8637 return 1;
8638
8639 return 0;
8640 }
8641
8642 /*
8643 * root_eb is the subtree root and is locked before this function is called.
8644 */
8645 static int account_shared_subtree(struct btrfs_trans_handle *trans,
8646 struct btrfs_root *root,
8647 struct extent_buffer *root_eb,
8648 u64 root_gen,
8649 int root_level)
8650 {
8651 int ret = 0;
8652 int level;
8653 struct extent_buffer *eb = root_eb;
8654 struct btrfs_path *path = NULL;
8655
8656 BUG_ON(root_level < 0 || root_level > BTRFS_MAX_LEVEL);
8657 BUG_ON(root_eb == NULL);
8658
8659 if (!root->fs_info->quota_enabled)
8660 return 0;
8661
8662 if (!extent_buffer_uptodate(root_eb)) {
8663 ret = btrfs_read_buffer(root_eb, root_gen);
8664 if (ret)
8665 goto out;
8666 }
8667
8668 if (root_level == 0) {
8669 ret = account_leaf_items(trans, root, root_eb);
8670 goto out;
8671 }
8672
8673 path = btrfs_alloc_path();
8674 if (!path)
8675 return -ENOMEM;
8676
8677 /*
8678 * Walk down the tree. Missing extent blocks are filled in as
8679 * we go. Metadata is accounted every time we read a new
8680 * extent block.
8681 *
8682 * When we reach a leaf, we account for file extent items in it,
8683 * walk back up the tree (adjusting slot pointers as we go)
8684 * and restart the search process.
8685 */
8686 extent_buffer_get(root_eb); /* For path */
8687 path->nodes[root_level] = root_eb;
8688 path->slots[root_level] = 0;
8689 path->locks[root_level] = 0; /* so release_path doesn't try to unlock */
8690 walk_down:
8691 level = root_level;
8692 while (level >= 0) {
8693 if (path->nodes[level] == NULL) {
8694 int parent_slot;
8695 u64 child_gen;
8696 u64 child_bytenr;
8697
8698 /* We need to get child blockptr/gen from
8699 * parent before we can read it. */
8700 eb = path->nodes[level + 1];
8701 parent_slot = path->slots[level + 1];
8702 child_bytenr = btrfs_node_blockptr(eb, parent_slot);
8703 child_gen = btrfs_node_ptr_generation(eb, parent_slot);
8704
8705 eb = read_tree_block(root, child_bytenr, child_gen);
8706 if (IS_ERR(eb)) {
8707 ret = PTR_ERR(eb);
8708 goto out;
8709 } else if (!extent_buffer_uptodate(eb)) {
8710 free_extent_buffer(eb);
8711 ret = -EIO;
8712 goto out;
8713 }
8714
8715 path->nodes[level] = eb;
8716 path->slots[level] = 0;
8717
8718 btrfs_tree_read_lock(eb);
8719 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
8720 path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
8721
8722 ret = btrfs_qgroup_insert_dirty_extent(trans,
8723 root->fs_info, child_bytenr,
8724 root->nodesize, GFP_NOFS);
8725 if (ret)
8726 goto out;
8727 }
8728
8729 if (level == 0) {
8730 ret = account_leaf_items(trans, root, path->nodes[level]);
8731 if (ret)
8732 goto out;
8733
8734 /* Nonzero return here means we completed our search */
8735 ret = adjust_slots_upwards(root, path, root_level);
8736 if (ret)
8737 break;
8738
8739 /* Restart search with new slots */
8740 goto walk_down;
8741 }
8742
8743 level--;
8744 }
8745
8746 ret = 0;
8747 out:
8748 btrfs_free_path(path);
8749
8750 return ret;
8751 }
8752
8753 /*
8754 * helper to process tree block while walking down the tree.
8755 *
8756 * when wc->stage == UPDATE_BACKREF, this function updates
8757 * back refs for pointers in the block.
8758 *
8759 * NOTE: return value 1 means we should stop walking down.
8760 */
8761 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
8762 struct btrfs_root *root,
8763 struct btrfs_path *path,
8764 struct walk_control *wc, int lookup_info)
8765 {
8766 int level = wc->level;
8767 struct extent_buffer *eb = path->nodes[level];
8768 u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8769 int ret;
8770
8771 if (wc->stage == UPDATE_BACKREF &&
8772 btrfs_header_owner(eb) != root->root_key.objectid)
8773 return 1;
8774
8775 /*
8776 * when reference count of tree block is 1, it won't increase
8777 * again. once full backref flag is set, we never clear it.
8778 */
8779 if (lookup_info &&
8780 ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
8781 (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
8782 BUG_ON(!path->locks[level]);
8783 ret = btrfs_lookup_extent_info(trans, root,
8784 eb->start, level, 1,
8785 &wc->refs[level],
8786 &wc->flags[level]);
8787 BUG_ON(ret == -ENOMEM);
8788 if (ret)
8789 return ret;
8790 BUG_ON(wc->refs[level] == 0);
8791 }
8792
8793 if (wc->stage == DROP_REFERENCE) {
8794 if (wc->refs[level] > 1)
8795 return 1;
8796
8797 if (path->locks[level] && !wc->keep_locks) {
8798 btrfs_tree_unlock_rw(eb, path->locks[level]);
8799 path->locks[level] = 0;
8800 }
8801 return 0;
8802 }
8803
8804 /* wc->stage == UPDATE_BACKREF */
8805 if (!(wc->flags[level] & flag)) {
8806 BUG_ON(!path->locks[level]);
8807 ret = btrfs_inc_ref(trans, root, eb, 1);
8808 BUG_ON(ret); /* -ENOMEM */
8809 ret = btrfs_dec_ref(trans, root, eb, 0);
8810 BUG_ON(ret); /* -ENOMEM */
8811 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
8812 eb->len, flag,
8813 btrfs_header_level(eb), 0);
8814 BUG_ON(ret); /* -ENOMEM */
8815 wc->flags[level] |= flag;
8816 }
8817
8818 /*
8819 * the block is shared by multiple trees, so it's not good to
8820 * keep the tree lock
8821 */
8822 if (path->locks[level] && level > 0) {
8823 btrfs_tree_unlock_rw(eb, path->locks[level]);
8824 path->locks[level] = 0;
8825 }
8826 return 0;
8827 }
8828
8829 /*
8830 * helper to process tree block pointer.
8831 *
8832 * when wc->stage == DROP_REFERENCE, this function checks
8833 * reference count of the block pointed to. if the block
8834 * is shared and we need update back refs for the subtree
8835 * rooted at the block, this function changes wc->stage to
8836 * UPDATE_BACKREF. if the block is shared and there is no
8837 * need to update back, this function drops the reference
8838 * to the block.
8839 *
8840 * NOTE: return value 1 means we should stop walking down.
8841 */
8842 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
8843 struct btrfs_root *root,
8844 struct btrfs_path *path,
8845 struct walk_control *wc, int *lookup_info)
8846 {
8847 u64 bytenr;
8848 u64 generation;
8849 u64 parent;
8850 u32 blocksize;
8851 struct btrfs_key key;
8852 struct extent_buffer *next;
8853 int level = wc->level;
8854 int reada = 0;
8855 int ret = 0;
8856 bool need_account = false;
8857
8858 generation = btrfs_node_ptr_generation(path->nodes[level],
8859 path->slots[level]);
8860 /*
8861 * if the lower level block was created before the snapshot
8862 * was created, we know there is no need to update back refs
8863 * for the subtree
8864 */
8865 if (wc->stage == UPDATE_BACKREF &&
8866 generation <= root->root_key.offset) {
8867 *lookup_info = 1;
8868 return 1;
8869 }
8870
8871 bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
8872 blocksize = root->nodesize;
8873
8874 next = btrfs_find_tree_block(root->fs_info, bytenr);
8875 if (!next) {
8876 next = btrfs_find_create_tree_block(root, bytenr);
8877 if (IS_ERR(next))
8878 return PTR_ERR(next);
8879
8880 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
8881 level - 1);
8882 reada = 1;
8883 }
8884 btrfs_tree_lock(next);
8885 btrfs_set_lock_blocking(next);
8886
8887 ret = btrfs_lookup_extent_info(trans, root, bytenr, level - 1, 1,
8888 &wc->refs[level - 1],
8889 &wc->flags[level - 1]);
8890 if (ret < 0) {
8891 btrfs_tree_unlock(next);
8892 return ret;
8893 }
8894
8895 if (unlikely(wc->refs[level - 1] == 0)) {
8896 btrfs_err(root->fs_info, "Missing references.");
8897 BUG();
8898 }
8899 *lookup_info = 0;
8900
8901 if (wc->stage == DROP_REFERENCE) {
8902 if (wc->refs[level - 1] > 1) {
8903 need_account = true;
8904 if (level == 1 &&
8905 (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8906 goto skip;
8907
8908 if (!wc->update_ref ||
8909 generation <= root->root_key.offset)
8910 goto skip;
8911
8912 btrfs_node_key_to_cpu(path->nodes[level], &key,
8913 path->slots[level]);
8914 ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
8915 if (ret < 0)
8916 goto skip;
8917
8918 wc->stage = UPDATE_BACKREF;
8919 wc->shared_level = level - 1;
8920 }
8921 } else {
8922 if (level == 1 &&
8923 (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8924 goto skip;
8925 }
8926
8927 if (!btrfs_buffer_uptodate(next, generation, 0)) {
8928 btrfs_tree_unlock(next);
8929 free_extent_buffer(next);
8930 next = NULL;
8931 *lookup_info = 1;
8932 }
8933
8934 if (!next) {
8935 if (reada && level == 1)
8936 reada_walk_down(trans, root, wc, path);
8937 next = read_tree_block(root, bytenr, generation);
8938 if (IS_ERR(next)) {
8939 return PTR_ERR(next);
8940 } else if (!extent_buffer_uptodate(next)) {
8941 free_extent_buffer(next);
8942 return -EIO;
8943 }
8944 btrfs_tree_lock(next);
8945 btrfs_set_lock_blocking(next);
8946 }
8947
8948 level--;
8949 BUG_ON(level != btrfs_header_level(next));
8950 path->nodes[level] = next;
8951 path->slots[level] = 0;
8952 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8953 wc->level = level;
8954 if (wc->level == 1)
8955 wc->reada_slot = 0;
8956 return 0;
8957 skip:
8958 wc->refs[level - 1] = 0;
8959 wc->flags[level - 1] = 0;
8960 if (wc->stage == DROP_REFERENCE) {
8961 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
8962 parent = path->nodes[level]->start;
8963 } else {
8964 BUG_ON(root->root_key.objectid !=
8965 btrfs_header_owner(path->nodes[level]));
8966 parent = 0;
8967 }
8968
8969 if (need_account) {
8970 ret = account_shared_subtree(trans, root, next,
8971 generation, level - 1);
8972 if (ret) {
8973 btrfs_err_rl(root->fs_info,
8974 "Error "
8975 "%d accounting shared subtree. Quota "
8976 "is out of sync, rescan required.",
8977 ret);
8978 }
8979 }
8980 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
8981 root->root_key.objectid, level - 1, 0);
8982 BUG_ON(ret); /* -ENOMEM */
8983 }
8984 btrfs_tree_unlock(next);
8985 free_extent_buffer(next);
8986 *lookup_info = 1;
8987 return 1;
8988 }
8989
8990 /*
8991 * helper to process tree block while walking up the tree.
8992 *
8993 * when wc->stage == DROP_REFERENCE, this function drops
8994 * reference count on the block.
8995 *
8996 * when wc->stage == UPDATE_BACKREF, this function changes
8997 * wc->stage back to DROP_REFERENCE if we changed wc->stage
8998 * to UPDATE_BACKREF previously while processing the block.
8999 *
9000 * NOTE: return value 1 means we should stop walking up.
9001 */
9002 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
9003 struct btrfs_root *root,
9004 struct btrfs_path *path,
9005 struct walk_control *wc)
9006 {
9007 int ret;
9008 int level = wc->level;
9009 struct extent_buffer *eb = path->nodes[level];
9010 u64 parent = 0;
9011
9012 if (wc->stage == UPDATE_BACKREF) {
9013 BUG_ON(wc->shared_level < level);
9014 if (level < wc->shared_level)
9015 goto out;
9016
9017 ret = find_next_key(path, level + 1, &wc->update_progress);
9018 if (ret > 0)
9019 wc->update_ref = 0;
9020
9021 wc->stage = DROP_REFERENCE;
9022 wc->shared_level = -1;
9023 path->slots[level] = 0;
9024
9025 /*
9026 * check reference count again if the block isn't locked.
9027 * we should start walking down the tree again if reference
9028 * count is one.
9029 */
9030 if (!path->locks[level]) {
9031 BUG_ON(level == 0);
9032 btrfs_tree_lock(eb);
9033 btrfs_set_lock_blocking(eb);
9034 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9035
9036 ret = btrfs_lookup_extent_info(trans, root,
9037 eb->start, level, 1,
9038 &wc->refs[level],
9039 &wc->flags[level]);
9040 if (ret < 0) {
9041 btrfs_tree_unlock_rw(eb, path->locks[level]);
9042 path->locks[level] = 0;
9043 return ret;
9044 }
9045 BUG_ON(wc->refs[level] == 0);
9046 if (wc->refs[level] == 1) {
9047 btrfs_tree_unlock_rw(eb, path->locks[level]);
9048 path->locks[level] = 0;
9049 return 1;
9050 }
9051 }
9052 }
9053
9054 /* wc->stage == DROP_REFERENCE */
9055 BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
9056
9057 if (wc->refs[level] == 1) {
9058 if (level == 0) {
9059 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
9060 ret = btrfs_dec_ref(trans, root, eb, 1);
9061 else
9062 ret = btrfs_dec_ref(trans, root, eb, 0);
9063 BUG_ON(ret); /* -ENOMEM */
9064 ret = account_leaf_items(trans, root, eb);
9065 if (ret) {
9066 btrfs_err_rl(root->fs_info,
9067 "error "
9068 "%d accounting leaf items. Quota "
9069 "is out of sync, rescan required.",
9070 ret);
9071 }
9072 }
9073 /* make block locked assertion in clean_tree_block happy */
9074 if (!path->locks[level] &&
9075 btrfs_header_generation(eb) == trans->transid) {
9076 btrfs_tree_lock(eb);
9077 btrfs_set_lock_blocking(eb);
9078 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9079 }
9080 clean_tree_block(trans, root->fs_info, eb);
9081 }
9082
9083 if (eb == root->node) {
9084 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
9085 parent = eb->start;
9086 else
9087 BUG_ON(root->root_key.objectid !=
9088 btrfs_header_owner(eb));
9089 } else {
9090 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
9091 parent = path->nodes[level + 1]->start;
9092 else
9093 BUG_ON(root->root_key.objectid !=
9094 btrfs_header_owner(path->nodes[level + 1]));
9095 }
9096
9097 btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
9098 out:
9099 wc->refs[level] = 0;
9100 wc->flags[level] = 0;
9101 return 0;
9102 }
9103
9104 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
9105 struct btrfs_root *root,
9106 struct btrfs_path *path,
9107 struct walk_control *wc)
9108 {
9109 int level = wc->level;
9110 int lookup_info = 1;
9111 int ret;
9112
9113 while (level >= 0) {
9114 ret = walk_down_proc(trans, root, path, wc, lookup_info);
9115 if (ret > 0)
9116 break;
9117
9118 if (level == 0)
9119 break;
9120
9121 if (path->slots[level] >=
9122 btrfs_header_nritems(path->nodes[level]))
9123 break;
9124
9125 ret = do_walk_down(trans, root, path, wc, &lookup_info);
9126 if (ret > 0) {
9127 path->slots[level]++;
9128 continue;
9129 } else if (ret < 0)
9130 return ret;
9131 level = wc->level;
9132 }
9133 return 0;
9134 }
9135
9136 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
9137 struct btrfs_root *root,
9138 struct btrfs_path *path,
9139 struct walk_control *wc, int max_level)
9140 {
9141 int level = wc->level;
9142 int ret;
9143
9144 path->slots[level] = btrfs_header_nritems(path->nodes[level]);
9145 while (level < max_level && path->nodes[level]) {
9146 wc->level = level;
9147 if (path->slots[level] + 1 <
9148 btrfs_header_nritems(path->nodes[level])) {
9149 path->slots[level]++;
9150 return 0;
9151 } else {
9152 ret = walk_up_proc(trans, root, path, wc);
9153 if (ret > 0)
9154 return 0;
9155
9156 if (path->locks[level]) {
9157 btrfs_tree_unlock_rw(path->nodes[level],
9158 path->locks[level]);
9159 path->locks[level] = 0;
9160 }
9161 free_extent_buffer(path->nodes[level]);
9162 path->nodes[level] = NULL;
9163 level++;
9164 }
9165 }
9166 return 1;
9167 }
9168
9169 /*
9170 * drop a subvolume tree.
9171 *
9172 * this function traverses the tree freeing any blocks that only
9173 * referenced by the tree.
9174 *
9175 * when a shared tree block is found. this function decreases its
9176 * reference count by one. if update_ref is true, this function
9177 * also make sure backrefs for the shared block and all lower level
9178 * blocks are properly updated.
9179 *
9180 * If called with for_reloc == 0, may exit early with -EAGAIN
9181 */
9182 int btrfs_drop_snapshot(struct btrfs_root *root,
9183 struct btrfs_block_rsv *block_rsv, int update_ref,
9184 int for_reloc)
9185 {
9186 struct btrfs_path *path;
9187 struct btrfs_trans_handle *trans;
9188 struct btrfs_root *tree_root = root->fs_info->tree_root;
9189 struct btrfs_root_item *root_item = &root->root_item;
9190 struct walk_control *wc;
9191 struct btrfs_key key;
9192 int err = 0;
9193 int ret;
9194 int level;
9195 bool root_dropped = false;
9196
9197 btrfs_debug(root->fs_info, "Drop subvolume %llu", root->objectid);
9198
9199 path = btrfs_alloc_path();
9200 if (!path) {
9201 err = -ENOMEM;
9202 goto out;
9203 }
9204
9205 wc = kzalloc(sizeof(*wc), GFP_NOFS);
9206 if (!wc) {
9207 btrfs_free_path(path);
9208 err = -ENOMEM;
9209 goto out;
9210 }
9211
9212 trans = btrfs_start_transaction(tree_root, 0);
9213 if (IS_ERR(trans)) {
9214 err = PTR_ERR(trans);
9215 goto out_free;
9216 }
9217
9218 if (block_rsv)
9219 trans->block_rsv = block_rsv;
9220
9221 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
9222 level = btrfs_header_level(root->node);
9223 path->nodes[level] = btrfs_lock_root_node(root);
9224 btrfs_set_lock_blocking(path->nodes[level]);
9225 path->slots[level] = 0;
9226 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9227 memset(&wc->update_progress, 0,
9228 sizeof(wc->update_progress));
9229 } else {
9230 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
9231 memcpy(&wc->update_progress, &key,
9232 sizeof(wc->update_progress));
9233
9234 level = root_item->drop_level;
9235 BUG_ON(level == 0);
9236 path->lowest_level = level;
9237 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
9238 path->lowest_level = 0;
9239 if (ret < 0) {
9240 err = ret;
9241 goto out_end_trans;
9242 }
9243 WARN_ON(ret > 0);
9244
9245 /*
9246 * unlock our path, this is safe because only this
9247 * function is allowed to delete this snapshot
9248 */
9249 btrfs_unlock_up_safe(path, 0);
9250
9251 level = btrfs_header_level(root->node);
9252 while (1) {
9253 btrfs_tree_lock(path->nodes[level]);
9254 btrfs_set_lock_blocking(path->nodes[level]);
9255 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9256
9257 ret = btrfs_lookup_extent_info(trans, root,
9258 path->nodes[level]->start,
9259 level, 1, &wc->refs[level],
9260 &wc->flags[level]);
9261 if (ret < 0) {
9262 err = ret;
9263 goto out_end_trans;
9264 }
9265 BUG_ON(wc->refs[level] == 0);
9266
9267 if (level == root_item->drop_level)
9268 break;
9269
9270 btrfs_tree_unlock(path->nodes[level]);
9271 path->locks[level] = 0;
9272 WARN_ON(wc->refs[level] != 1);
9273 level--;
9274 }
9275 }
9276
9277 wc->level = level;
9278 wc->shared_level = -1;
9279 wc->stage = DROP_REFERENCE;
9280 wc->update_ref = update_ref;
9281 wc->keep_locks = 0;
9282 wc->for_reloc = for_reloc;
9283 wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
9284
9285 while (1) {
9286
9287 ret = walk_down_tree(trans, root, path, wc);
9288 if (ret < 0) {
9289 err = ret;
9290 break;
9291 }
9292
9293 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
9294 if (ret < 0) {
9295 err = ret;
9296 break;
9297 }
9298
9299 if (ret > 0) {
9300 BUG_ON(wc->stage != DROP_REFERENCE);
9301 break;
9302 }
9303
9304 if (wc->stage == DROP_REFERENCE) {
9305 level = wc->level;
9306 btrfs_node_key(path->nodes[level],
9307 &root_item->drop_progress,
9308 path->slots[level]);
9309 root_item->drop_level = level;
9310 }
9311
9312 BUG_ON(wc->level == 0);
9313 if (btrfs_should_end_transaction(trans, tree_root) ||
9314 (!for_reloc && btrfs_need_cleaner_sleep(root))) {
9315 ret = btrfs_update_root(trans, tree_root,
9316 &root->root_key,
9317 root_item);
9318 if (ret) {
9319 btrfs_abort_transaction(trans, ret);
9320 err = ret;
9321 goto out_end_trans;
9322 }
9323
9324 btrfs_end_transaction_throttle(trans, tree_root);
9325 if (!for_reloc && btrfs_need_cleaner_sleep(root)) {
9326 pr_debug("BTRFS: drop snapshot early exit\n");
9327 err = -EAGAIN;
9328 goto out_free;
9329 }
9330
9331 trans = btrfs_start_transaction(tree_root, 0);
9332 if (IS_ERR(trans)) {
9333 err = PTR_ERR(trans);
9334 goto out_free;
9335 }
9336 if (block_rsv)
9337 trans->block_rsv = block_rsv;
9338 }
9339 }
9340 btrfs_release_path(path);
9341 if (err)
9342 goto out_end_trans;
9343
9344 ret = btrfs_del_root(trans, tree_root, &root->root_key);
9345 if (ret) {
9346 btrfs_abort_transaction(trans, ret);
9347 goto out_end_trans;
9348 }
9349
9350 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
9351 ret = btrfs_find_root(tree_root, &root->root_key, path,
9352 NULL, NULL);
9353 if (ret < 0) {
9354 btrfs_abort_transaction(trans, ret);
9355 err = ret;
9356 goto out_end_trans;
9357 } else if (ret > 0) {
9358 /* if we fail to delete the orphan item this time
9359 * around, it'll get picked up the next time.
9360 *
9361 * The most common failure here is just -ENOENT.
9362 */
9363 btrfs_del_orphan_item(trans, tree_root,
9364 root->root_key.objectid);
9365 }
9366 }
9367
9368 if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
9369 btrfs_add_dropped_root(trans, root);
9370 } else {
9371 free_extent_buffer(root->node);
9372 free_extent_buffer(root->commit_root);
9373 btrfs_put_fs_root(root);
9374 }
9375 root_dropped = true;
9376 out_end_trans:
9377 btrfs_end_transaction_throttle(trans, tree_root);
9378 out_free:
9379 kfree(wc);
9380 btrfs_free_path(path);
9381 out:
9382 /*
9383 * So if we need to stop dropping the snapshot for whatever reason we
9384 * need to make sure to add it back to the dead root list so that we
9385 * keep trying to do the work later. This also cleans up roots if we
9386 * don't have it in the radix (like when we recover after a power fail
9387 * or unmount) so we don't leak memory.
9388 */
9389 if (!for_reloc && root_dropped == false)
9390 btrfs_add_dead_root(root);
9391 if (err && err != -EAGAIN)
9392 btrfs_handle_fs_error(root->fs_info, err, NULL);
9393 return err;
9394 }
9395
9396 /*
9397 * drop subtree rooted at tree block 'node'.
9398 *
9399 * NOTE: this function will unlock and release tree block 'node'
9400 * only used by relocation code
9401 */
9402 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
9403 struct btrfs_root *root,
9404 struct extent_buffer *node,
9405 struct extent_buffer *parent)
9406 {
9407 struct btrfs_path *path;
9408 struct walk_control *wc;
9409 int level;
9410 int parent_level;
9411 int ret = 0;
9412 int wret;
9413
9414 BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
9415
9416 path = btrfs_alloc_path();
9417 if (!path)
9418 return -ENOMEM;
9419
9420 wc = kzalloc(sizeof(*wc), GFP_NOFS);
9421 if (!wc) {
9422 btrfs_free_path(path);
9423 return -ENOMEM;
9424 }
9425
9426 btrfs_assert_tree_locked(parent);
9427 parent_level = btrfs_header_level(parent);
9428 extent_buffer_get(parent);
9429 path->nodes[parent_level] = parent;
9430 path->slots[parent_level] = btrfs_header_nritems(parent);
9431
9432 btrfs_assert_tree_locked(node);
9433 level = btrfs_header_level(node);
9434 path->nodes[level] = node;
9435 path->slots[level] = 0;
9436 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9437
9438 wc->refs[parent_level] = 1;
9439 wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
9440 wc->level = level;
9441 wc->shared_level = -1;
9442 wc->stage = DROP_REFERENCE;
9443 wc->update_ref = 0;
9444 wc->keep_locks = 1;
9445 wc->for_reloc = 1;
9446 wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
9447
9448 while (1) {
9449 wret = walk_down_tree(trans, root, path, wc);
9450 if (wret < 0) {
9451 ret = wret;
9452 break;
9453 }
9454
9455 wret = walk_up_tree(trans, root, path, wc, parent_level);
9456 if (wret < 0)
9457 ret = wret;
9458 if (wret != 0)
9459 break;
9460 }
9461
9462 kfree(wc);
9463 btrfs_free_path(path);
9464 return ret;
9465 }
9466
9467 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
9468 {
9469 u64 num_devices;
9470 u64 stripped;
9471
9472 /*
9473 * if restripe for this chunk_type is on pick target profile and
9474 * return, otherwise do the usual balance
9475 */
9476 stripped = get_restripe_target(root->fs_info, flags);
9477 if (stripped)
9478 return extended_to_chunk(stripped);
9479
9480 num_devices = root->fs_info->fs_devices->rw_devices;
9481
9482 stripped = BTRFS_BLOCK_GROUP_RAID0 |
9483 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
9484 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
9485
9486 if (num_devices == 1) {
9487 stripped |= BTRFS_BLOCK_GROUP_DUP;
9488 stripped = flags & ~stripped;
9489
9490 /* turn raid0 into single device chunks */
9491 if (flags & BTRFS_BLOCK_GROUP_RAID0)
9492 return stripped;
9493
9494 /* turn mirroring into duplication */
9495 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
9496 BTRFS_BLOCK_GROUP_RAID10))
9497 return stripped | BTRFS_BLOCK_GROUP_DUP;
9498 } else {
9499 /* they already had raid on here, just return */
9500 if (flags & stripped)
9501 return flags;
9502
9503 stripped |= BTRFS_BLOCK_GROUP_DUP;
9504 stripped = flags & ~stripped;
9505
9506 /* switch duplicated blocks with raid1 */
9507 if (flags & BTRFS_BLOCK_GROUP_DUP)
9508 return stripped | BTRFS_BLOCK_GROUP_RAID1;
9509
9510 /* this is drive concat, leave it alone */
9511 }
9512
9513 return flags;
9514 }
9515
9516 static int inc_block_group_ro(struct btrfs_block_group_cache *cache, int force)
9517 {
9518 struct btrfs_space_info *sinfo = cache->space_info;
9519 u64 num_bytes;
9520 u64 min_allocable_bytes;
9521 int ret = -ENOSPC;
9522
9523 /*
9524 * We need some metadata space and system metadata space for
9525 * allocating chunks in some corner cases until we force to set
9526 * it to be readonly.
9527 */
9528 if ((sinfo->flags &
9529 (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
9530 !force)
9531 min_allocable_bytes = SZ_1M;
9532 else
9533 min_allocable_bytes = 0;
9534
9535 spin_lock(&sinfo->lock);
9536 spin_lock(&cache->lock);
9537
9538 if (cache->ro) {
9539 cache->ro++;
9540 ret = 0;
9541 goto out;
9542 }
9543
9544 num_bytes = cache->key.offset - cache->reserved - cache->pinned -
9545 cache->bytes_super - btrfs_block_group_used(&cache->item);
9546
9547 if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
9548 sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
9549 min_allocable_bytes <= sinfo->total_bytes) {
9550 sinfo->bytes_readonly += num_bytes;
9551 cache->ro++;
9552 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
9553 ret = 0;
9554 }
9555 out:
9556 spin_unlock(&cache->lock);
9557 spin_unlock(&sinfo->lock);
9558 return ret;
9559 }
9560
9561 int btrfs_inc_block_group_ro(struct btrfs_root *root,
9562 struct btrfs_block_group_cache *cache)
9563
9564 {
9565 struct btrfs_trans_handle *trans;
9566 u64 alloc_flags;
9567 int ret;
9568
9569 again:
9570 trans = btrfs_join_transaction(root);
9571 if (IS_ERR(trans))
9572 return PTR_ERR(trans);
9573
9574 /*
9575 * we're not allowed to set block groups readonly after the dirty
9576 * block groups cache has started writing. If it already started,
9577 * back off and let this transaction commit
9578 */
9579 mutex_lock(&root->fs_info->ro_block_group_mutex);
9580 if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
9581 u64 transid = trans->transid;
9582
9583 mutex_unlock(&root->fs_info->ro_block_group_mutex);
9584 btrfs_end_transaction(trans, root);
9585
9586 ret = btrfs_wait_for_commit(root, transid);
9587 if (ret)
9588 return ret;
9589 goto again;
9590 }
9591
9592 /*
9593 * if we are changing raid levels, try to allocate a corresponding
9594 * block group with the new raid level.
9595 */
9596 alloc_flags = update_block_group_flags(root, cache->flags);
9597 if (alloc_flags != cache->flags) {
9598 ret = do_chunk_alloc(trans, root, alloc_flags,
9599 CHUNK_ALLOC_FORCE);
9600 /*
9601 * ENOSPC is allowed here, we may have enough space
9602 * already allocated at the new raid level to
9603 * carry on
9604 */
9605 if (ret == -ENOSPC)
9606 ret = 0;
9607 if (ret < 0)
9608 goto out;
9609 }
9610
9611 ret = inc_block_group_ro(cache, 0);
9612 if (!ret)
9613 goto out;
9614 alloc_flags = get_alloc_profile(root, cache->space_info->flags);
9615 ret = do_chunk_alloc(trans, root, alloc_flags,
9616 CHUNK_ALLOC_FORCE);
9617 if (ret < 0)
9618 goto out;
9619 ret = inc_block_group_ro(cache, 0);
9620 out:
9621 if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
9622 alloc_flags = update_block_group_flags(root, cache->flags);
9623 lock_chunks(root->fs_info->chunk_root);
9624 check_system_chunk(trans, root, alloc_flags);
9625 unlock_chunks(root->fs_info->chunk_root);
9626 }
9627 mutex_unlock(&root->fs_info->ro_block_group_mutex);
9628
9629 btrfs_end_transaction(trans, root);
9630 return ret;
9631 }
9632
9633 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
9634 struct btrfs_root *root, u64 type)
9635 {
9636 u64 alloc_flags = get_alloc_profile(root, type);
9637 return do_chunk_alloc(trans, root, alloc_flags,
9638 CHUNK_ALLOC_FORCE);
9639 }
9640
9641 /*
9642 * helper to account the unused space of all the readonly block group in the
9643 * space_info. takes mirrors into account.
9644 */
9645 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
9646 {
9647 struct btrfs_block_group_cache *block_group;
9648 u64 free_bytes = 0;
9649 int factor;
9650
9651 /* It's df, we don't care if it's racy */
9652 if (list_empty(&sinfo->ro_bgs))
9653 return 0;
9654
9655 spin_lock(&sinfo->lock);
9656 list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
9657 spin_lock(&block_group->lock);
9658
9659 if (!block_group->ro) {
9660 spin_unlock(&block_group->lock);
9661 continue;
9662 }
9663
9664 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
9665 BTRFS_BLOCK_GROUP_RAID10 |
9666 BTRFS_BLOCK_GROUP_DUP))
9667 factor = 2;
9668 else
9669 factor = 1;
9670
9671 free_bytes += (block_group->key.offset -
9672 btrfs_block_group_used(&block_group->item)) *
9673 factor;
9674
9675 spin_unlock(&block_group->lock);
9676 }
9677 spin_unlock(&sinfo->lock);
9678
9679 return free_bytes;
9680 }
9681
9682 void btrfs_dec_block_group_ro(struct btrfs_root *root,
9683 struct btrfs_block_group_cache *cache)
9684 {
9685 struct btrfs_space_info *sinfo = cache->space_info;
9686 u64 num_bytes;
9687
9688 BUG_ON(!cache->ro);
9689
9690 spin_lock(&sinfo->lock);
9691 spin_lock(&cache->lock);
9692 if (!--cache->ro) {
9693 num_bytes = cache->key.offset - cache->reserved -
9694 cache->pinned - cache->bytes_super -
9695 btrfs_block_group_used(&cache->item);
9696 sinfo->bytes_readonly -= num_bytes;
9697 list_del_init(&cache->ro_list);
9698 }
9699 spin_unlock(&cache->lock);
9700 spin_unlock(&sinfo->lock);
9701 }
9702
9703 /*
9704 * checks to see if its even possible to relocate this block group.
9705 *
9706 * @return - -1 if it's not a good idea to relocate this block group, 0 if its
9707 * ok to go ahead and try.
9708 */
9709 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
9710 {
9711 struct btrfs_block_group_cache *block_group;
9712 struct btrfs_space_info *space_info;
9713 struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
9714 struct btrfs_device *device;
9715 struct btrfs_trans_handle *trans;
9716 u64 min_free;
9717 u64 dev_min = 1;
9718 u64 dev_nr = 0;
9719 u64 target;
9720 int debug;
9721 int index;
9722 int full = 0;
9723 int ret = 0;
9724
9725 debug = btrfs_test_opt(root->fs_info, ENOSPC_DEBUG);
9726
9727 block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
9728
9729 /* odd, couldn't find the block group, leave it alone */
9730 if (!block_group) {
9731 if (debug)
9732 btrfs_warn(root->fs_info,
9733 "can't find block group for bytenr %llu",
9734 bytenr);
9735 return -1;
9736 }
9737
9738 min_free = btrfs_block_group_used(&block_group->item);
9739
9740 /* no bytes used, we're good */
9741 if (!min_free)
9742 goto out;
9743
9744 space_info = block_group->space_info;
9745 spin_lock(&space_info->lock);
9746
9747 full = space_info->full;
9748
9749 /*
9750 * if this is the last block group we have in this space, we can't
9751 * relocate it unless we're able to allocate a new chunk below.
9752 *
9753 * Otherwise, we need to make sure we have room in the space to handle
9754 * all of the extents from this block group. If we can, we're good
9755 */
9756 if ((space_info->total_bytes != block_group->key.offset) &&
9757 (space_info->bytes_used + space_info->bytes_reserved +
9758 space_info->bytes_pinned + space_info->bytes_readonly +
9759 min_free < space_info->total_bytes)) {
9760 spin_unlock(&space_info->lock);
9761 goto out;
9762 }
9763 spin_unlock(&space_info->lock);
9764
9765 /*
9766 * ok we don't have enough space, but maybe we have free space on our
9767 * devices to allocate new chunks for relocation, so loop through our
9768 * alloc devices and guess if we have enough space. if this block
9769 * group is going to be restriped, run checks against the target
9770 * profile instead of the current one.
9771 */
9772 ret = -1;
9773
9774 /*
9775 * index:
9776 * 0: raid10
9777 * 1: raid1
9778 * 2: dup
9779 * 3: raid0
9780 * 4: single
9781 */
9782 target = get_restripe_target(root->fs_info, block_group->flags);
9783 if (target) {
9784 index = __get_raid_index(extended_to_chunk(target));
9785 } else {
9786 /*
9787 * this is just a balance, so if we were marked as full
9788 * we know there is no space for a new chunk
9789 */
9790 if (full) {
9791 if (debug)
9792 btrfs_warn(root->fs_info,
9793 "no space to alloc new chunk for block group %llu",
9794 block_group->key.objectid);
9795 goto out;
9796 }
9797
9798 index = get_block_group_index(block_group);
9799 }
9800
9801 if (index == BTRFS_RAID_RAID10) {
9802 dev_min = 4;
9803 /* Divide by 2 */
9804 min_free >>= 1;
9805 } else if (index == BTRFS_RAID_RAID1) {
9806 dev_min = 2;
9807 } else if (index == BTRFS_RAID_DUP) {
9808 /* Multiply by 2 */
9809 min_free <<= 1;
9810 } else if (index == BTRFS_RAID_RAID0) {
9811 dev_min = fs_devices->rw_devices;
9812 min_free = div64_u64(min_free, dev_min);
9813 }
9814
9815 /* We need to do this so that we can look at pending chunks */
9816 trans = btrfs_join_transaction(root);
9817 if (IS_ERR(trans)) {
9818 ret = PTR_ERR(trans);
9819 goto out;
9820 }
9821
9822 mutex_lock(&root->fs_info->chunk_mutex);
9823 list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
9824 u64 dev_offset;
9825
9826 /*
9827 * check to make sure we can actually find a chunk with enough
9828 * space to fit our block group in.
9829 */
9830 if (device->total_bytes > device->bytes_used + min_free &&
9831 !device->is_tgtdev_for_dev_replace) {
9832 ret = find_free_dev_extent(trans, device, min_free,
9833 &dev_offset, NULL);
9834 if (!ret)
9835 dev_nr++;
9836
9837 if (dev_nr >= dev_min)
9838 break;
9839
9840 ret = -1;
9841 }
9842 }
9843 if (debug && ret == -1)
9844 btrfs_warn(root->fs_info,
9845 "no space to allocate a new chunk for block group %llu",
9846 block_group->key.objectid);
9847 mutex_unlock(&root->fs_info->chunk_mutex);
9848 btrfs_end_transaction(trans, root);
9849 out:
9850 btrfs_put_block_group(block_group);
9851 return ret;
9852 }
9853
9854 static int find_first_block_group(struct btrfs_root *root,
9855 struct btrfs_path *path, struct btrfs_key *key)
9856 {
9857 int ret = 0;
9858 struct btrfs_key found_key;
9859 struct extent_buffer *leaf;
9860 int slot;
9861
9862 ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
9863 if (ret < 0)
9864 goto out;
9865
9866 while (1) {
9867 slot = path->slots[0];
9868 leaf = path->nodes[0];
9869 if (slot >= btrfs_header_nritems(leaf)) {
9870 ret = btrfs_next_leaf(root, path);
9871 if (ret == 0)
9872 continue;
9873 if (ret < 0)
9874 goto out;
9875 break;
9876 }
9877 btrfs_item_key_to_cpu(leaf, &found_key, slot);
9878
9879 if (found_key.objectid >= key->objectid &&
9880 found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
9881 struct extent_map_tree *em_tree;
9882 struct extent_map *em;
9883
9884 em_tree = &root->fs_info->mapping_tree.map_tree;
9885 read_lock(&em_tree->lock);
9886 em = lookup_extent_mapping(em_tree, found_key.objectid,
9887 found_key.offset);
9888 read_unlock(&em_tree->lock);
9889 if (!em) {
9890 btrfs_err(root->fs_info,
9891 "logical %llu len %llu found bg but no related chunk",
9892 found_key.objectid, found_key.offset);
9893 ret = -ENOENT;
9894 } else {
9895 ret = 0;
9896 }
9897 free_extent_map(em);
9898 goto out;
9899 }
9900 path->slots[0]++;
9901 }
9902 out:
9903 return ret;
9904 }
9905
9906 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
9907 {
9908 struct btrfs_block_group_cache *block_group;
9909 u64 last = 0;
9910
9911 while (1) {
9912 struct inode *inode;
9913
9914 block_group = btrfs_lookup_first_block_group(info, last);
9915 while (block_group) {
9916 spin_lock(&block_group->lock);
9917 if (block_group->iref)
9918 break;
9919 spin_unlock(&block_group->lock);
9920 block_group = next_block_group(info->tree_root,
9921 block_group);
9922 }
9923 if (!block_group) {
9924 if (last == 0)
9925 break;
9926 last = 0;
9927 continue;
9928 }
9929
9930 inode = block_group->inode;
9931 block_group->iref = 0;
9932 block_group->inode = NULL;
9933 spin_unlock(&block_group->lock);
9934 ASSERT(block_group->io_ctl.inode == NULL);
9935 iput(inode);
9936 last = block_group->key.objectid + block_group->key.offset;
9937 btrfs_put_block_group(block_group);
9938 }
9939 }
9940
9941 int btrfs_free_block_groups(struct btrfs_fs_info *info)
9942 {
9943 struct btrfs_block_group_cache *block_group;
9944 struct btrfs_space_info *space_info;
9945 struct btrfs_caching_control *caching_ctl;
9946 struct rb_node *n;
9947
9948 down_write(&info->commit_root_sem);
9949 while (!list_empty(&info->caching_block_groups)) {
9950 caching_ctl = list_entry(info->caching_block_groups.next,
9951 struct btrfs_caching_control, list);
9952 list_del(&caching_ctl->list);
9953 put_caching_control(caching_ctl);
9954 }
9955 up_write(&info->commit_root_sem);
9956
9957 spin_lock(&info->unused_bgs_lock);
9958 while (!list_empty(&info->unused_bgs)) {
9959 block_group = list_first_entry(&info->unused_bgs,
9960 struct btrfs_block_group_cache,
9961 bg_list);
9962 list_del_init(&block_group->bg_list);
9963 btrfs_put_block_group(block_group);
9964 }
9965 spin_unlock(&info->unused_bgs_lock);
9966
9967 spin_lock(&info->block_group_cache_lock);
9968 while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
9969 block_group = rb_entry(n, struct btrfs_block_group_cache,
9970 cache_node);
9971 rb_erase(&block_group->cache_node,
9972 &info->block_group_cache_tree);
9973 RB_CLEAR_NODE(&block_group->cache_node);
9974 spin_unlock(&info->block_group_cache_lock);
9975
9976 down_write(&block_group->space_info->groups_sem);
9977 list_del(&block_group->list);
9978 up_write(&block_group->space_info->groups_sem);
9979
9980 if (block_group->cached == BTRFS_CACHE_STARTED)
9981 wait_block_group_cache_done(block_group);
9982
9983 /*
9984 * We haven't cached this block group, which means we could
9985 * possibly have excluded extents on this block group.
9986 */
9987 if (block_group->cached == BTRFS_CACHE_NO ||
9988 block_group->cached == BTRFS_CACHE_ERROR)
9989 free_excluded_extents(info->extent_root, block_group);
9990
9991 btrfs_remove_free_space_cache(block_group);
9992 ASSERT(list_empty(&block_group->dirty_list));
9993 ASSERT(list_empty(&block_group->io_list));
9994 ASSERT(list_empty(&block_group->bg_list));
9995 ASSERT(atomic_read(&block_group->count) == 1);
9996 btrfs_put_block_group(block_group);
9997
9998 spin_lock(&info->block_group_cache_lock);
9999 }
10000 spin_unlock(&info->block_group_cache_lock);
10001
10002 /* now that all the block groups are freed, go through and
10003 * free all the space_info structs. This is only called during
10004 * the final stages of unmount, and so we know nobody is
10005 * using them. We call synchronize_rcu() once before we start,
10006 * just to be on the safe side.
10007 */
10008 synchronize_rcu();
10009
10010 release_global_block_rsv(info);
10011
10012 while (!list_empty(&info->space_info)) {
10013 int i;
10014
10015 space_info = list_entry(info->space_info.next,
10016 struct btrfs_space_info,
10017 list);
10018
10019 /*
10020 * Do not hide this behind enospc_debug, this is actually
10021 * important and indicates a real bug if this happens.
10022 */
10023 if (WARN_ON(space_info->bytes_pinned > 0 ||
10024 space_info->bytes_reserved > 0 ||
10025 space_info->bytes_may_use > 0))
10026 dump_space_info(space_info, 0, 0);
10027 list_del(&space_info->list);
10028 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
10029 struct kobject *kobj;
10030 kobj = space_info->block_group_kobjs[i];
10031 space_info->block_group_kobjs[i] = NULL;
10032 if (kobj) {
10033 kobject_del(kobj);
10034 kobject_put(kobj);
10035 }
10036 }
10037 kobject_del(&space_info->kobj);
10038 kobject_put(&space_info->kobj);
10039 }
10040 return 0;
10041 }
10042
10043 static void __link_block_group(struct btrfs_space_info *space_info,
10044 struct btrfs_block_group_cache *cache)
10045 {
10046 int index = get_block_group_index(cache);
10047 bool first = false;
10048
10049 down_write(&space_info->groups_sem);
10050 if (list_empty(&space_info->block_groups[index]))
10051 first = true;
10052 list_add_tail(&cache->list, &space_info->block_groups[index]);
10053 up_write(&space_info->groups_sem);
10054
10055 if (first) {
10056 struct raid_kobject *rkobj;
10057 int ret;
10058
10059 rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
10060 if (!rkobj)
10061 goto out_err;
10062 rkobj->raid_type = index;
10063 kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
10064 ret = kobject_add(&rkobj->kobj, &space_info->kobj,
10065 "%s", get_raid_name(index));
10066 if (ret) {
10067 kobject_put(&rkobj->kobj);
10068 goto out_err;
10069 }
10070 space_info->block_group_kobjs[index] = &rkobj->kobj;
10071 }
10072
10073 return;
10074 out_err:
10075 pr_warn("BTRFS: failed to add kobject for block cache. ignoring.\n");
10076 }
10077
10078 static struct btrfs_block_group_cache *
10079 btrfs_create_block_group_cache(struct btrfs_root *root, u64 start, u64 size)
10080 {
10081 struct btrfs_block_group_cache *cache;
10082
10083 cache = kzalloc(sizeof(*cache), GFP_NOFS);
10084 if (!cache)
10085 return NULL;
10086
10087 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
10088 GFP_NOFS);
10089 if (!cache->free_space_ctl) {
10090 kfree(cache);
10091 return NULL;
10092 }
10093
10094 cache->key.objectid = start;
10095 cache->key.offset = size;
10096 cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
10097
10098 cache->sectorsize = root->sectorsize;
10099 cache->fs_info = root->fs_info;
10100 cache->full_stripe_len = btrfs_full_stripe_len(root,
10101 &root->fs_info->mapping_tree,
10102 start);
10103 set_free_space_tree_thresholds(cache);
10104
10105 atomic_set(&cache->count, 1);
10106 spin_lock_init(&cache->lock);
10107 init_rwsem(&cache->data_rwsem);
10108 INIT_LIST_HEAD(&cache->list);
10109 INIT_LIST_HEAD(&cache->cluster_list);
10110 INIT_LIST_HEAD(&cache->bg_list);
10111 INIT_LIST_HEAD(&cache->ro_list);
10112 INIT_LIST_HEAD(&cache->dirty_list);
10113 INIT_LIST_HEAD(&cache->io_list);
10114 btrfs_init_free_space_ctl(cache);
10115 atomic_set(&cache->trimming, 0);
10116 mutex_init(&cache->free_space_lock);
10117
10118 return cache;
10119 }
10120
10121 int btrfs_read_block_groups(struct btrfs_root *root)
10122 {
10123 struct btrfs_path *path;
10124 int ret;
10125 struct btrfs_block_group_cache *cache;
10126 struct btrfs_fs_info *info = root->fs_info;
10127 struct btrfs_space_info *space_info;
10128 struct btrfs_key key;
10129 struct btrfs_key found_key;
10130 struct extent_buffer *leaf;
10131 int need_clear = 0;
10132 u64 cache_gen;
10133
10134 root = info->extent_root;
10135 key.objectid = 0;
10136 key.offset = 0;
10137 key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
10138 path = btrfs_alloc_path();
10139 if (!path)
10140 return -ENOMEM;
10141 path->reada = READA_FORWARD;
10142
10143 cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
10144 if (btrfs_test_opt(root->fs_info, SPACE_CACHE) &&
10145 btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
10146 need_clear = 1;
10147 if (btrfs_test_opt(root->fs_info, CLEAR_CACHE))
10148 need_clear = 1;
10149
10150 while (1) {
10151 ret = find_first_block_group(root, path, &key);
10152 if (ret > 0)
10153 break;
10154 if (ret != 0)
10155 goto error;
10156
10157 leaf = path->nodes[0];
10158 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
10159
10160 cache = btrfs_create_block_group_cache(root, found_key.objectid,
10161 found_key.offset);
10162 if (!cache) {
10163 ret = -ENOMEM;
10164 goto error;
10165 }
10166
10167 if (need_clear) {
10168 /*
10169 * When we mount with old space cache, we need to
10170 * set BTRFS_DC_CLEAR and set dirty flag.
10171 *
10172 * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
10173 * truncate the old free space cache inode and
10174 * setup a new one.
10175 * b) Setting 'dirty flag' makes sure that we flush
10176 * the new space cache info onto disk.
10177 */
10178 if (btrfs_test_opt(root->fs_info, SPACE_CACHE))
10179 cache->disk_cache_state = BTRFS_DC_CLEAR;
10180 }
10181
10182 read_extent_buffer(leaf, &cache->item,
10183 btrfs_item_ptr_offset(leaf, path->slots[0]),
10184 sizeof(cache->item));
10185 cache->flags = btrfs_block_group_flags(&cache->item);
10186
10187 key.objectid = found_key.objectid + found_key.offset;
10188 btrfs_release_path(path);
10189
10190 /*
10191 * We need to exclude the super stripes now so that the space
10192 * info has super bytes accounted for, otherwise we'll think
10193 * we have more space than we actually do.
10194 */
10195 ret = exclude_super_stripes(root, cache);
10196 if (ret) {
10197 /*
10198 * We may have excluded something, so call this just in
10199 * case.
10200 */
10201 free_excluded_extents(root, cache);
10202 btrfs_put_block_group(cache);
10203 goto error;
10204 }
10205
10206 /*
10207 * check for two cases, either we are full, and therefore
10208 * don't need to bother with the caching work since we won't
10209 * find any space, or we are empty, and we can just add all
10210 * the space in and be done with it. This saves us _alot_ of
10211 * time, particularly in the full case.
10212 */
10213 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
10214 cache->last_byte_to_unpin = (u64)-1;
10215 cache->cached = BTRFS_CACHE_FINISHED;
10216 free_excluded_extents(root, cache);
10217 } else if (btrfs_block_group_used(&cache->item) == 0) {
10218 cache->last_byte_to_unpin = (u64)-1;
10219 cache->cached = BTRFS_CACHE_FINISHED;
10220 add_new_free_space(cache, root->fs_info,
10221 found_key.objectid,
10222 found_key.objectid +
10223 found_key.offset);
10224 free_excluded_extents(root, cache);
10225 }
10226
10227 ret = btrfs_add_block_group_cache(root->fs_info, cache);
10228 if (ret) {
10229 btrfs_remove_free_space_cache(cache);
10230 btrfs_put_block_group(cache);
10231 goto error;
10232 }
10233
10234 trace_btrfs_add_block_group(root->fs_info, cache, 0);
10235 ret = update_space_info(info, cache->flags, found_key.offset,
10236 btrfs_block_group_used(&cache->item),
10237 cache->bytes_super, &space_info);
10238 if (ret) {
10239 btrfs_remove_free_space_cache(cache);
10240 spin_lock(&info->block_group_cache_lock);
10241 rb_erase(&cache->cache_node,
10242 &info->block_group_cache_tree);
10243 RB_CLEAR_NODE(&cache->cache_node);
10244 spin_unlock(&info->block_group_cache_lock);
10245 btrfs_put_block_group(cache);
10246 goto error;
10247 }
10248
10249 cache->space_info = space_info;
10250
10251 __link_block_group(space_info, cache);
10252
10253 set_avail_alloc_bits(root->fs_info, cache->flags);
10254 if (btrfs_chunk_readonly(root, cache->key.objectid)) {
10255 inc_block_group_ro(cache, 1);
10256 } else if (btrfs_block_group_used(&cache->item) == 0) {
10257 spin_lock(&info->unused_bgs_lock);
10258 /* Should always be true but just in case. */
10259 if (list_empty(&cache->bg_list)) {
10260 btrfs_get_block_group(cache);
10261 list_add_tail(&cache->bg_list,
10262 &info->unused_bgs);
10263 }
10264 spin_unlock(&info->unused_bgs_lock);
10265 }
10266 }
10267
10268 list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
10269 if (!(get_alloc_profile(root, space_info->flags) &
10270 (BTRFS_BLOCK_GROUP_RAID10 |
10271 BTRFS_BLOCK_GROUP_RAID1 |
10272 BTRFS_BLOCK_GROUP_RAID5 |
10273 BTRFS_BLOCK_GROUP_RAID6 |
10274 BTRFS_BLOCK_GROUP_DUP)))
10275 continue;
10276 /*
10277 * avoid allocating from un-mirrored block group if there are
10278 * mirrored block groups.
10279 */
10280 list_for_each_entry(cache,
10281 &space_info->block_groups[BTRFS_RAID_RAID0],
10282 list)
10283 inc_block_group_ro(cache, 1);
10284 list_for_each_entry(cache,
10285 &space_info->block_groups[BTRFS_RAID_SINGLE],
10286 list)
10287 inc_block_group_ro(cache, 1);
10288 }
10289
10290 init_global_block_rsv(info);
10291 ret = 0;
10292 error:
10293 btrfs_free_path(path);
10294 return ret;
10295 }
10296
10297 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
10298 struct btrfs_root *root)
10299 {
10300 struct btrfs_block_group_cache *block_group, *tmp;
10301 struct btrfs_root *extent_root = root->fs_info->extent_root;
10302 struct btrfs_block_group_item item;
10303 struct btrfs_key key;
10304 int ret = 0;
10305 bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
10306
10307 trans->can_flush_pending_bgs = false;
10308 list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
10309 if (ret)
10310 goto next;
10311
10312 spin_lock(&block_group->lock);
10313 memcpy(&item, &block_group->item, sizeof(item));
10314 memcpy(&key, &block_group->key, sizeof(key));
10315 spin_unlock(&block_group->lock);
10316
10317 ret = btrfs_insert_item(trans, extent_root, &key, &item,
10318 sizeof(item));
10319 if (ret)
10320 btrfs_abort_transaction(trans, ret);
10321 ret = btrfs_finish_chunk_alloc(trans, extent_root,
10322 key.objectid, key.offset);
10323 if (ret)
10324 btrfs_abort_transaction(trans, ret);
10325 add_block_group_free_space(trans, root->fs_info, block_group);
10326 /* already aborted the transaction if it failed. */
10327 next:
10328 list_del_init(&block_group->bg_list);
10329 }
10330 trans->can_flush_pending_bgs = can_flush_pending_bgs;
10331 }
10332
10333 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
10334 struct btrfs_root *root, u64 bytes_used,
10335 u64 type, u64 chunk_objectid, u64 chunk_offset,
10336 u64 size)
10337 {
10338 int ret;
10339 struct btrfs_root *extent_root;
10340 struct btrfs_block_group_cache *cache;
10341 extent_root = root->fs_info->extent_root;
10342
10343 btrfs_set_log_full_commit(root->fs_info, trans);
10344
10345 cache = btrfs_create_block_group_cache(root, chunk_offset, size);
10346 if (!cache)
10347 return -ENOMEM;
10348
10349 btrfs_set_block_group_used(&cache->item, bytes_used);
10350 btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
10351 btrfs_set_block_group_flags(&cache->item, type);
10352
10353 cache->flags = type;
10354 cache->last_byte_to_unpin = (u64)-1;
10355 cache->cached = BTRFS_CACHE_FINISHED;
10356 cache->needs_free_space = 1;
10357 ret = exclude_super_stripes(root, cache);
10358 if (ret) {
10359 /*
10360 * We may have excluded something, so call this just in
10361 * case.
10362 */
10363 free_excluded_extents(root, cache);
10364 btrfs_put_block_group(cache);
10365 return ret;
10366 }
10367
10368 add_new_free_space(cache, root->fs_info, chunk_offset,
10369 chunk_offset + size);
10370
10371 free_excluded_extents(root, cache);
10372
10373 #ifdef CONFIG_BTRFS_DEBUG
10374 if (btrfs_should_fragment_free_space(root, cache)) {
10375 u64 new_bytes_used = size - bytes_used;
10376
10377 bytes_used += new_bytes_used >> 1;
10378 fragment_free_space(root, cache);
10379 }
10380 #endif
10381 /*
10382 * Call to ensure the corresponding space_info object is created and
10383 * assigned to our block group, but don't update its counters just yet.
10384 * We want our bg to be added to the rbtree with its ->space_info set.
10385 */
10386 ret = update_space_info(root->fs_info, cache->flags, 0, 0, 0,
10387 &cache->space_info);
10388 if (ret) {
10389 btrfs_remove_free_space_cache(cache);
10390 btrfs_put_block_group(cache);
10391 return ret;
10392 }
10393
10394 ret = btrfs_add_block_group_cache(root->fs_info, cache);
10395 if (ret) {
10396 btrfs_remove_free_space_cache(cache);
10397 btrfs_put_block_group(cache);
10398 return ret;
10399 }
10400
10401 /*
10402 * Now that our block group has its ->space_info set and is inserted in
10403 * the rbtree, update the space info's counters.
10404 */
10405 trace_btrfs_add_block_group(root->fs_info, cache, 1);
10406 ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
10407 cache->bytes_super, &cache->space_info);
10408 if (ret) {
10409 btrfs_remove_free_space_cache(cache);
10410 spin_lock(&root->fs_info->block_group_cache_lock);
10411 rb_erase(&cache->cache_node,
10412 &root->fs_info->block_group_cache_tree);
10413 RB_CLEAR_NODE(&cache->cache_node);
10414 spin_unlock(&root->fs_info->block_group_cache_lock);
10415 btrfs_put_block_group(cache);
10416 return ret;
10417 }
10418 update_global_block_rsv(root->fs_info);
10419
10420 __link_block_group(cache->space_info, cache);
10421
10422 list_add_tail(&cache->bg_list, &trans->new_bgs);
10423
10424 set_avail_alloc_bits(extent_root->fs_info, type);
10425 return 0;
10426 }
10427
10428 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
10429 {
10430 u64 extra_flags = chunk_to_extended(flags) &
10431 BTRFS_EXTENDED_PROFILE_MASK;
10432
10433 write_seqlock(&fs_info->profiles_lock);
10434 if (flags & BTRFS_BLOCK_GROUP_DATA)
10435 fs_info->avail_data_alloc_bits &= ~extra_flags;
10436 if (flags & BTRFS_BLOCK_GROUP_METADATA)
10437 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
10438 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
10439 fs_info->avail_system_alloc_bits &= ~extra_flags;
10440 write_sequnlock(&fs_info->profiles_lock);
10441 }
10442
10443 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
10444 struct btrfs_root *root, u64 group_start,
10445 struct extent_map *em)
10446 {
10447 struct btrfs_path *path;
10448 struct btrfs_block_group_cache *block_group;
10449 struct btrfs_free_cluster *cluster;
10450 struct btrfs_root *tree_root = root->fs_info->tree_root;
10451 struct btrfs_key key;
10452 struct inode *inode;
10453 struct kobject *kobj = NULL;
10454 int ret;
10455 int index;
10456 int factor;
10457 struct btrfs_caching_control *caching_ctl = NULL;
10458 bool remove_em;
10459
10460 root = root->fs_info->extent_root;
10461
10462 block_group = btrfs_lookup_block_group(root->fs_info, group_start);
10463 BUG_ON(!block_group);
10464 BUG_ON(!block_group->ro);
10465
10466 /*
10467 * Free the reserved super bytes from this block group before
10468 * remove it.
10469 */
10470 free_excluded_extents(root, block_group);
10471
10472 memcpy(&key, &block_group->key, sizeof(key));
10473 index = get_block_group_index(block_group);
10474 if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
10475 BTRFS_BLOCK_GROUP_RAID1 |
10476 BTRFS_BLOCK_GROUP_RAID10))
10477 factor = 2;
10478 else
10479 factor = 1;
10480
10481 /* make sure this block group isn't part of an allocation cluster */
10482 cluster = &root->fs_info->data_alloc_cluster;
10483 spin_lock(&cluster->refill_lock);
10484 btrfs_return_cluster_to_free_space(block_group, cluster);
10485 spin_unlock(&cluster->refill_lock);
10486
10487 /*
10488 * make sure this block group isn't part of a metadata
10489 * allocation cluster
10490 */
10491 cluster = &root->fs_info->meta_alloc_cluster;
10492 spin_lock(&cluster->refill_lock);
10493 btrfs_return_cluster_to_free_space(block_group, cluster);
10494 spin_unlock(&cluster->refill_lock);
10495
10496 path = btrfs_alloc_path();
10497 if (!path) {
10498 ret = -ENOMEM;
10499 goto out;
10500 }
10501
10502 /*
10503 * get the inode first so any iput calls done for the io_list
10504 * aren't the final iput (no unlinks allowed now)
10505 */
10506 inode = lookup_free_space_inode(tree_root, block_group, path);
10507
10508 mutex_lock(&trans->transaction->cache_write_mutex);
10509 /*
10510 * make sure our free spache cache IO is done before remove the
10511 * free space inode
10512 */
10513 spin_lock(&trans->transaction->dirty_bgs_lock);
10514 if (!list_empty(&block_group->io_list)) {
10515 list_del_init(&block_group->io_list);
10516
10517 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
10518
10519 spin_unlock(&trans->transaction->dirty_bgs_lock);
10520 btrfs_wait_cache_io(root, trans, block_group,
10521 &block_group->io_ctl, path,
10522 block_group->key.objectid);
10523 btrfs_put_block_group(block_group);
10524 spin_lock(&trans->transaction->dirty_bgs_lock);
10525 }
10526
10527 if (!list_empty(&block_group->dirty_list)) {
10528 list_del_init(&block_group->dirty_list);
10529 btrfs_put_block_group(block_group);
10530 }
10531 spin_unlock(&trans->transaction->dirty_bgs_lock);
10532 mutex_unlock(&trans->transaction->cache_write_mutex);
10533
10534 if (!IS_ERR(inode)) {
10535 ret = btrfs_orphan_add(trans, inode);
10536 if (ret) {
10537 btrfs_add_delayed_iput(inode);
10538 goto out;
10539 }
10540 clear_nlink(inode);
10541 /* One for the block groups ref */
10542 spin_lock(&block_group->lock);
10543 if (block_group->iref) {
10544 block_group->iref = 0;
10545 block_group->inode = NULL;
10546 spin_unlock(&block_group->lock);
10547 iput(inode);
10548 } else {
10549 spin_unlock(&block_group->lock);
10550 }
10551 /* One for our lookup ref */
10552 btrfs_add_delayed_iput(inode);
10553 }
10554
10555 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
10556 key.offset = block_group->key.objectid;
10557 key.type = 0;
10558
10559 ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
10560 if (ret < 0)
10561 goto out;
10562 if (ret > 0)
10563 btrfs_release_path(path);
10564 if (ret == 0) {
10565 ret = btrfs_del_item(trans, tree_root, path);
10566 if (ret)
10567 goto out;
10568 btrfs_release_path(path);
10569 }
10570
10571 spin_lock(&root->fs_info->block_group_cache_lock);
10572 rb_erase(&block_group->cache_node,
10573 &root->fs_info->block_group_cache_tree);
10574 RB_CLEAR_NODE(&block_group->cache_node);
10575
10576 if (root->fs_info->first_logical_byte == block_group->key.objectid)
10577 root->fs_info->first_logical_byte = (u64)-1;
10578 spin_unlock(&root->fs_info->block_group_cache_lock);
10579
10580 down_write(&block_group->space_info->groups_sem);
10581 /*
10582 * we must use list_del_init so people can check to see if they
10583 * are still on the list after taking the semaphore
10584 */
10585 list_del_init(&block_group->list);
10586 if (list_empty(&block_group->space_info->block_groups[index])) {
10587 kobj = block_group->space_info->block_group_kobjs[index];
10588 block_group->space_info->block_group_kobjs[index] = NULL;
10589 clear_avail_alloc_bits(root->fs_info, block_group->flags);
10590 }
10591 up_write(&block_group->space_info->groups_sem);
10592 if (kobj) {
10593 kobject_del(kobj);
10594 kobject_put(kobj);
10595 }
10596
10597 if (block_group->has_caching_ctl)
10598 caching_ctl = get_caching_control(block_group);
10599 if (block_group->cached == BTRFS_CACHE_STARTED)
10600 wait_block_group_cache_done(block_group);
10601 if (block_group->has_caching_ctl) {
10602 down_write(&root->fs_info->commit_root_sem);
10603 if (!caching_ctl) {
10604 struct btrfs_caching_control *ctl;
10605
10606 list_for_each_entry(ctl,
10607 &root->fs_info->caching_block_groups, list)
10608 if (ctl->block_group == block_group) {
10609 caching_ctl = ctl;
10610 atomic_inc(&caching_ctl->count);
10611 break;
10612 }
10613 }
10614 if (caching_ctl)
10615 list_del_init(&caching_ctl->list);
10616 up_write(&root->fs_info->commit_root_sem);
10617 if (caching_ctl) {
10618 /* Once for the caching bgs list and once for us. */
10619 put_caching_control(caching_ctl);
10620 put_caching_control(caching_ctl);
10621 }
10622 }
10623
10624 spin_lock(&trans->transaction->dirty_bgs_lock);
10625 if (!list_empty(&block_group->dirty_list)) {
10626 WARN_ON(1);
10627 }
10628 if (!list_empty(&block_group->io_list)) {
10629 WARN_ON(1);
10630 }
10631 spin_unlock(&trans->transaction->dirty_bgs_lock);
10632 btrfs_remove_free_space_cache(block_group);
10633
10634 spin_lock(&block_group->space_info->lock);
10635 list_del_init(&block_group->ro_list);
10636
10637 if (btrfs_test_opt(root->fs_info, ENOSPC_DEBUG)) {
10638 WARN_ON(block_group->space_info->total_bytes
10639 < block_group->key.offset);
10640 WARN_ON(block_group->space_info->bytes_readonly
10641 < block_group->key.offset);
10642 WARN_ON(block_group->space_info->disk_total
10643 < block_group->key.offset * factor);
10644 }
10645 block_group->space_info->total_bytes -= block_group->key.offset;
10646 block_group->space_info->bytes_readonly -= block_group->key.offset;
10647 block_group->space_info->disk_total -= block_group->key.offset * factor;
10648
10649 spin_unlock(&block_group->space_info->lock);
10650
10651 memcpy(&key, &block_group->key, sizeof(key));
10652
10653 lock_chunks(root);
10654 if (!list_empty(&em->list)) {
10655 /* We're in the transaction->pending_chunks list. */
10656 free_extent_map(em);
10657 }
10658 spin_lock(&block_group->lock);
10659 block_group->removed = 1;
10660 /*
10661 * At this point trimming can't start on this block group, because we
10662 * removed the block group from the tree fs_info->block_group_cache_tree
10663 * so no one can't find it anymore and even if someone already got this
10664 * block group before we removed it from the rbtree, they have already
10665 * incremented block_group->trimming - if they didn't, they won't find
10666 * any free space entries because we already removed them all when we
10667 * called btrfs_remove_free_space_cache().
10668 *
10669 * And we must not remove the extent map from the fs_info->mapping_tree
10670 * to prevent the same logical address range and physical device space
10671 * ranges from being reused for a new block group. This is because our
10672 * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
10673 * completely transactionless, so while it is trimming a range the
10674 * currently running transaction might finish and a new one start,
10675 * allowing for new block groups to be created that can reuse the same
10676 * physical device locations unless we take this special care.
10677 *
10678 * There may also be an implicit trim operation if the file system
10679 * is mounted with -odiscard. The same protections must remain
10680 * in place until the extents have been discarded completely when
10681 * the transaction commit has completed.
10682 */
10683 remove_em = (atomic_read(&block_group->trimming) == 0);
10684 /*
10685 * Make sure a trimmer task always sees the em in the pinned_chunks list
10686 * if it sees block_group->removed == 1 (needs to lock block_group->lock
10687 * before checking block_group->removed).
10688 */
10689 if (!remove_em) {
10690 /*
10691 * Our em might be in trans->transaction->pending_chunks which
10692 * is protected by fs_info->chunk_mutex ([lock|unlock]_chunks),
10693 * and so is the fs_info->pinned_chunks list.
10694 *
10695 * So at this point we must be holding the chunk_mutex to avoid
10696 * any races with chunk allocation (more specifically at
10697 * volumes.c:contains_pending_extent()), to ensure it always
10698 * sees the em, either in the pending_chunks list or in the
10699 * pinned_chunks list.
10700 */
10701 list_move_tail(&em->list, &root->fs_info->pinned_chunks);
10702 }
10703 spin_unlock(&block_group->lock);
10704
10705 if (remove_em) {
10706 struct extent_map_tree *em_tree;
10707
10708 em_tree = &root->fs_info->mapping_tree.map_tree;
10709 write_lock(&em_tree->lock);
10710 /*
10711 * The em might be in the pending_chunks list, so make sure the
10712 * chunk mutex is locked, since remove_extent_mapping() will
10713 * delete us from that list.
10714 */
10715 remove_extent_mapping(em_tree, em);
10716 write_unlock(&em_tree->lock);
10717 /* once for the tree */
10718 free_extent_map(em);
10719 }
10720
10721 unlock_chunks(root);
10722
10723 ret = remove_block_group_free_space(trans, root->fs_info, block_group);
10724 if (ret)
10725 goto out;
10726
10727 btrfs_put_block_group(block_group);
10728 btrfs_put_block_group(block_group);
10729
10730 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
10731 if (ret > 0)
10732 ret = -EIO;
10733 if (ret < 0)
10734 goto out;
10735
10736 ret = btrfs_del_item(trans, root, path);
10737 out:
10738 btrfs_free_path(path);
10739 return ret;
10740 }
10741
10742 struct btrfs_trans_handle *
10743 btrfs_start_trans_remove_block_group(struct btrfs_fs_info *fs_info,
10744 const u64 chunk_offset)
10745 {
10746 struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree;
10747 struct extent_map *em;
10748 struct map_lookup *map;
10749 unsigned int num_items;
10750
10751 read_lock(&em_tree->lock);
10752 em = lookup_extent_mapping(em_tree, chunk_offset, 1);
10753 read_unlock(&em_tree->lock);
10754 ASSERT(em && em->start == chunk_offset);
10755
10756 /*
10757 * We need to reserve 3 + N units from the metadata space info in order
10758 * to remove a block group (done at btrfs_remove_chunk() and at
10759 * btrfs_remove_block_group()), which are used for:
10760 *
10761 * 1 unit for adding the free space inode's orphan (located in the tree
10762 * of tree roots).
10763 * 1 unit for deleting the block group item (located in the extent
10764 * tree).
10765 * 1 unit for deleting the free space item (located in tree of tree
10766 * roots).
10767 * N units for deleting N device extent items corresponding to each
10768 * stripe (located in the device tree).
10769 *
10770 * In order to remove a block group we also need to reserve units in the
10771 * system space info in order to update the chunk tree (update one or
10772 * more device items and remove one chunk item), but this is done at
10773 * btrfs_remove_chunk() through a call to check_system_chunk().
10774 */
10775 map = em->map_lookup;
10776 num_items = 3 + map->num_stripes;
10777 free_extent_map(em);
10778
10779 return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
10780 num_items, 1);
10781 }
10782
10783 /*
10784 * Process the unused_bgs list and remove any that don't have any allocated
10785 * space inside of them.
10786 */
10787 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
10788 {
10789 struct btrfs_block_group_cache *block_group;
10790 struct btrfs_space_info *space_info;
10791 struct btrfs_root *root = fs_info->extent_root;
10792 struct btrfs_trans_handle *trans;
10793 int ret = 0;
10794
10795 if (!fs_info->open)
10796 return;
10797
10798 spin_lock(&fs_info->unused_bgs_lock);
10799 while (!list_empty(&fs_info->unused_bgs)) {
10800 u64 start, end;
10801 int trimming;
10802
10803 block_group = list_first_entry(&fs_info->unused_bgs,
10804 struct btrfs_block_group_cache,
10805 bg_list);
10806 list_del_init(&block_group->bg_list);
10807
10808 space_info = block_group->space_info;
10809
10810 if (ret || btrfs_mixed_space_info(space_info)) {
10811 btrfs_put_block_group(block_group);
10812 continue;
10813 }
10814 spin_unlock(&fs_info->unused_bgs_lock);
10815
10816 mutex_lock(&fs_info->delete_unused_bgs_mutex);
10817
10818 /* Don't want to race with allocators so take the groups_sem */
10819 down_write(&space_info->groups_sem);
10820 spin_lock(&block_group->lock);
10821 if (block_group->reserved ||
10822 btrfs_block_group_used(&block_group->item) ||
10823 block_group->ro ||
10824 list_is_singular(&block_group->list)) {
10825 /*
10826 * We want to bail if we made new allocations or have
10827 * outstanding allocations in this block group. We do
10828 * the ro check in case balance is currently acting on
10829 * this block group.
10830 */
10831 spin_unlock(&block_group->lock);
10832 up_write(&space_info->groups_sem);
10833 goto next;
10834 }
10835 spin_unlock(&block_group->lock);
10836
10837 /* We don't want to force the issue, only flip if it's ok. */
10838 ret = inc_block_group_ro(block_group, 0);
10839 up_write(&space_info->groups_sem);
10840 if (ret < 0) {
10841 ret = 0;
10842 goto next;
10843 }
10844
10845 /*
10846 * Want to do this before we do anything else so we can recover
10847 * properly if we fail to join the transaction.
10848 */
10849 trans = btrfs_start_trans_remove_block_group(fs_info,
10850 block_group->key.objectid);
10851 if (IS_ERR(trans)) {
10852 btrfs_dec_block_group_ro(root, block_group);
10853 ret = PTR_ERR(trans);
10854 goto next;
10855 }
10856
10857 /*
10858 * We could have pending pinned extents for this block group,
10859 * just delete them, we don't care about them anymore.
10860 */
10861 start = block_group->key.objectid;
10862 end = start + block_group->key.offset - 1;
10863 /*
10864 * Hold the unused_bg_unpin_mutex lock to avoid racing with
10865 * btrfs_finish_extent_commit(). If we are at transaction N,
10866 * another task might be running finish_extent_commit() for the
10867 * previous transaction N - 1, and have seen a range belonging
10868 * to the block group in freed_extents[] before we were able to
10869 * clear the whole block group range from freed_extents[]. This
10870 * means that task can lookup for the block group after we
10871 * unpinned it from freed_extents[] and removed it, leading to
10872 * a BUG_ON() at btrfs_unpin_extent_range().
10873 */
10874 mutex_lock(&fs_info->unused_bg_unpin_mutex);
10875 ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
10876 EXTENT_DIRTY);
10877 if (ret) {
10878 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10879 btrfs_dec_block_group_ro(root, block_group);
10880 goto end_trans;
10881 }
10882 ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
10883 EXTENT_DIRTY);
10884 if (ret) {
10885 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10886 btrfs_dec_block_group_ro(root, block_group);
10887 goto end_trans;
10888 }
10889 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10890
10891 /* Reset pinned so btrfs_put_block_group doesn't complain */
10892 spin_lock(&space_info->lock);
10893 spin_lock(&block_group->lock);
10894
10895 space_info->bytes_pinned -= block_group->pinned;
10896 space_info->bytes_readonly += block_group->pinned;
10897 percpu_counter_add(&space_info->total_bytes_pinned,
10898 -block_group->pinned);
10899 block_group->pinned = 0;
10900
10901 spin_unlock(&block_group->lock);
10902 spin_unlock(&space_info->lock);
10903
10904 /* DISCARD can flip during remount */
10905 trimming = btrfs_test_opt(root->fs_info, DISCARD);
10906
10907 /* Implicit trim during transaction commit. */
10908 if (trimming)
10909 btrfs_get_block_group_trimming(block_group);
10910
10911 /*
10912 * Btrfs_remove_chunk will abort the transaction if things go
10913 * horribly wrong.
10914 */
10915 ret = btrfs_remove_chunk(trans, root,
10916 block_group->key.objectid);
10917
10918 if (ret) {
10919 if (trimming)
10920 btrfs_put_block_group_trimming(block_group);
10921 goto end_trans;
10922 }
10923
10924 /*
10925 * If we're not mounted with -odiscard, we can just forget
10926 * about this block group. Otherwise we'll need to wait
10927 * until transaction commit to do the actual discard.
10928 */
10929 if (trimming) {
10930 spin_lock(&fs_info->unused_bgs_lock);
10931 /*
10932 * A concurrent scrub might have added us to the list
10933 * fs_info->unused_bgs, so use a list_move operation
10934 * to add the block group to the deleted_bgs list.
10935 */
10936 list_move(&block_group->bg_list,
10937 &trans->transaction->deleted_bgs);
10938 spin_unlock(&fs_info->unused_bgs_lock);
10939 btrfs_get_block_group(block_group);
10940 }
10941 end_trans:
10942 btrfs_end_transaction(trans, root);
10943 next:
10944 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
10945 btrfs_put_block_group(block_group);
10946 spin_lock(&fs_info->unused_bgs_lock);
10947 }
10948 spin_unlock(&fs_info->unused_bgs_lock);
10949 }
10950
10951 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
10952 {
10953 struct btrfs_space_info *space_info;
10954 struct btrfs_super_block *disk_super;
10955 u64 features;
10956 u64 flags;
10957 int mixed = 0;
10958 int ret;
10959
10960 disk_super = fs_info->super_copy;
10961 if (!btrfs_super_root(disk_super))
10962 return -EINVAL;
10963
10964 features = btrfs_super_incompat_flags(disk_super);
10965 if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
10966 mixed = 1;
10967
10968 flags = BTRFS_BLOCK_GROUP_SYSTEM;
10969 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
10970 if (ret)
10971 goto out;
10972
10973 if (mixed) {
10974 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
10975 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
10976 } else {
10977 flags = BTRFS_BLOCK_GROUP_METADATA;
10978 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
10979 if (ret)
10980 goto out;
10981
10982 flags = BTRFS_BLOCK_GROUP_DATA;
10983 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
10984 }
10985 out:
10986 return ret;
10987 }
10988
10989 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
10990 {
10991 return unpin_extent_range(root, start, end, false);
10992 }
10993
10994 /*
10995 * It used to be that old block groups would be left around forever.
10996 * Iterating over them would be enough to trim unused space. Since we
10997 * now automatically remove them, we also need to iterate over unallocated
10998 * space.
10999 *
11000 * We don't want a transaction for this since the discard may take a
11001 * substantial amount of time. We don't require that a transaction be
11002 * running, but we do need to take a running transaction into account
11003 * to ensure that we're not discarding chunks that were released in
11004 * the current transaction.
11005 *
11006 * Holding the chunks lock will prevent other threads from allocating
11007 * or releasing chunks, but it won't prevent a running transaction
11008 * from committing and releasing the memory that the pending chunks
11009 * list head uses. For that, we need to take a reference to the
11010 * transaction.
11011 */
11012 static int btrfs_trim_free_extents(struct btrfs_device *device,
11013 u64 minlen, u64 *trimmed)
11014 {
11015 u64 start = 0, len = 0;
11016 int ret;
11017
11018 *trimmed = 0;
11019
11020 /* Not writeable = nothing to do. */
11021 if (!device->writeable)
11022 return 0;
11023
11024 /* No free space = nothing to do. */
11025 if (device->total_bytes <= device->bytes_used)
11026 return 0;
11027
11028 ret = 0;
11029
11030 while (1) {
11031 struct btrfs_fs_info *fs_info = device->dev_root->fs_info;
11032 struct btrfs_transaction *trans;
11033 u64 bytes;
11034
11035 ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
11036 if (ret)
11037 return ret;
11038
11039 down_read(&fs_info->commit_root_sem);
11040
11041 spin_lock(&fs_info->trans_lock);
11042 trans = fs_info->running_transaction;
11043 if (trans)
11044 atomic_inc(&trans->use_count);
11045 spin_unlock(&fs_info->trans_lock);
11046
11047 ret = find_free_dev_extent_start(trans, device, minlen, start,
11048 &start, &len);
11049 if (trans)
11050 btrfs_put_transaction(trans);
11051
11052 if (ret) {
11053 up_read(&fs_info->commit_root_sem);
11054 mutex_unlock(&fs_info->chunk_mutex);
11055 if (ret == -ENOSPC)
11056 ret = 0;
11057 break;
11058 }
11059
11060 ret = btrfs_issue_discard(device->bdev, start, len, &bytes);
11061 up_read(&fs_info->commit_root_sem);
11062 mutex_unlock(&fs_info->chunk_mutex);
11063
11064 if (ret)
11065 break;
11066
11067 start += len;
11068 *trimmed += bytes;
11069
11070 if (fatal_signal_pending(current)) {
11071 ret = -ERESTARTSYS;
11072 break;
11073 }
11074
11075 cond_resched();
11076 }
11077
11078 return ret;
11079 }
11080
11081 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
11082 {
11083 struct btrfs_fs_info *fs_info = root->fs_info;
11084 struct btrfs_block_group_cache *cache = NULL;
11085 struct btrfs_device *device;
11086 struct list_head *devices;
11087 u64 group_trimmed;
11088 u64 start;
11089 u64 end;
11090 u64 trimmed = 0;
11091 u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
11092 int ret = 0;
11093
11094 /*
11095 * try to trim all FS space, our block group may start from non-zero.
11096 */
11097 if (range->len == total_bytes)
11098 cache = btrfs_lookup_first_block_group(fs_info, range->start);
11099 else
11100 cache = btrfs_lookup_block_group(fs_info, range->start);
11101
11102 while (cache) {
11103 if (cache->key.objectid >= (range->start + range->len)) {
11104 btrfs_put_block_group(cache);
11105 break;
11106 }
11107
11108 start = max(range->start, cache->key.objectid);
11109 end = min(range->start + range->len,
11110 cache->key.objectid + cache->key.offset);
11111
11112 if (end - start >= range->minlen) {
11113 if (!block_group_cache_done(cache)) {
11114 ret = cache_block_group(cache, 0);
11115 if (ret) {
11116 btrfs_put_block_group(cache);
11117 break;
11118 }
11119 ret = wait_block_group_cache_done(cache);
11120 if (ret) {
11121 btrfs_put_block_group(cache);
11122 break;
11123 }
11124 }
11125 ret = btrfs_trim_block_group(cache,
11126 &group_trimmed,
11127 start,
11128 end,
11129 range->minlen);
11130
11131 trimmed += group_trimmed;
11132 if (ret) {
11133 btrfs_put_block_group(cache);
11134 break;
11135 }
11136 }
11137
11138 cache = next_block_group(fs_info->tree_root, cache);
11139 }
11140
11141 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
11142 devices = &root->fs_info->fs_devices->alloc_list;
11143 list_for_each_entry(device, devices, dev_alloc_list) {
11144 ret = btrfs_trim_free_extents(device, range->minlen,
11145 &group_trimmed);
11146 if (ret)
11147 break;
11148
11149 trimmed += group_trimmed;
11150 }
11151 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
11152
11153 range->len = trimmed;
11154 return ret;
11155 }
11156
11157 /*
11158 * btrfs_{start,end}_write_no_snapshoting() are similar to
11159 * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
11160 * data into the page cache through nocow before the subvolume is snapshoted,
11161 * but flush the data into disk after the snapshot creation, or to prevent
11162 * operations while snapshoting is ongoing and that cause the snapshot to be
11163 * inconsistent (writes followed by expanding truncates for example).
11164 */
11165 void btrfs_end_write_no_snapshoting(struct btrfs_root *root)
11166 {
11167 percpu_counter_dec(&root->subv_writers->counter);
11168 /*
11169 * Make sure counter is updated before we wake up waiters.
11170 */
11171 smp_mb();
11172 if (waitqueue_active(&root->subv_writers->wait))
11173 wake_up(&root->subv_writers->wait);
11174 }
11175
11176 int btrfs_start_write_no_snapshoting(struct btrfs_root *root)
11177 {
11178 if (atomic_read(&root->will_be_snapshoted))
11179 return 0;
11180
11181 percpu_counter_inc(&root->subv_writers->counter);
11182 /*
11183 * Make sure counter is updated before we check for snapshot creation.
11184 */
11185 smp_mb();
11186 if (atomic_read(&root->will_be_snapshoted)) {
11187 btrfs_end_write_no_snapshoting(root);
11188 return 0;
11189 }
11190 return 1;
11191 }
11192
11193 static int wait_snapshoting_atomic_t(atomic_t *a)
11194 {
11195 schedule();
11196 return 0;
11197 }
11198
11199 void btrfs_wait_for_snapshot_creation(struct btrfs_root *root)
11200 {
11201 while (true) {
11202 int ret;
11203
11204 ret = btrfs_start_write_no_snapshoting(root);
11205 if (ret)
11206 break;
11207 wait_on_atomic_t(&root->will_be_snapshoted,
11208 wait_snapshoting_atomic_t,
11209 TASK_UNINTERRUPTIBLE);
11210 }
11211 }
CRIS linux kernel tree