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Btrfs: don't BUG() during drop snapshot
[linux/fpc-iii.git] / fs / btrfs / extent-tree.c
blob11802eaaab548282135c6839a32051c115585d33
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_fs_info *fs_info,
91 struct btrfs_space_info *info, u64 bytes,
92 int dump_block_groups);
93 static int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
94 u64 ram_bytes, u64 num_bytes, int delalloc);
95 static int btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
96 u64 num_bytes, int delalloc);
97 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
98 u64 num_bytes);
99 int btrfs_pin_extent(struct btrfs_root *root,
100 u64 bytenr, u64 num_bytes, int reserved);
101 static int __reserve_metadata_bytes(struct btrfs_root *root,
102 struct btrfs_space_info *space_info,
103 u64 orig_bytes,
104 enum btrfs_reserve_flush_enum flush);
105 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
106 struct btrfs_space_info *space_info,
107 u64 num_bytes);
108 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
109 struct btrfs_space_info *space_info,
110 u64 num_bytes);
111
112 static noinline int
113 block_group_cache_done(struct btrfs_block_group_cache *cache)
114 {
115 smp_mb();
116 return cache->cached == BTRFS_CACHE_FINISHED ||
117 cache->cached == BTRFS_CACHE_ERROR;
118 }
119
120 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
121 {
122 return (cache->flags & bits) == bits;
123 }
124
125 void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
126 {
127 atomic_inc(&cache->count);
128 }
129
130 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
131 {
132 if (atomic_dec_and_test(&cache->count)) {
133 WARN_ON(cache->pinned > 0);
134 WARN_ON(cache->reserved > 0);
135 kfree(cache->free_space_ctl);
136 kfree(cache);
137 }
138 }
139
140 /*
141 * this adds the block group to the fs_info rb tree for the block group
142 * cache
143 */
144 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
145 struct btrfs_block_group_cache *block_group)
146 {
147 struct rb_node **p;
148 struct rb_node *parent = NULL;
149 struct btrfs_block_group_cache *cache;
150
151 spin_lock(&info->block_group_cache_lock);
152 p = &info->block_group_cache_tree.rb_node;
153
154 while (*p) {
155 parent = *p;
156 cache = rb_entry(parent, struct btrfs_block_group_cache,
157 cache_node);
158 if (block_group->key.objectid < cache->key.objectid) {
159 p = &(*p)->rb_left;
160 } else if (block_group->key.objectid > cache->key.objectid) {
161 p = &(*p)->rb_right;
162 } else {
163 spin_unlock(&info->block_group_cache_lock);
164 return -EEXIST;
165 }
166 }
167
168 rb_link_node(&block_group->cache_node, parent, p);
169 rb_insert_color(&block_group->cache_node,
170 &info->block_group_cache_tree);
171
172 if (info->first_logical_byte > block_group->key.objectid)
173 info->first_logical_byte = block_group->key.objectid;
174
175 spin_unlock(&info->block_group_cache_lock);
176
177 return 0;
178 }
179
180 /*
181 * This will return the block group at or after bytenr if contains is 0, else
182 * it will return the block group that contains the bytenr
183 */
184 static struct btrfs_block_group_cache *
185 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
186 int contains)
187 {
188 struct btrfs_block_group_cache *cache, *ret = NULL;
189 struct rb_node *n;
190 u64 end, start;
191
192 spin_lock(&info->block_group_cache_lock);
193 n = info->block_group_cache_tree.rb_node;
194
195 while (n) {
196 cache = rb_entry(n, struct btrfs_block_group_cache,
197 cache_node);
198 end = cache->key.objectid + cache->key.offset - 1;
199 start = cache->key.objectid;
200
201 if (bytenr < start) {
202 if (!contains && (!ret || start < ret->key.objectid))
203 ret = cache;
204 n = n->rb_left;
205 } else if (bytenr > start) {
206 if (contains && bytenr <= end) {
207 ret = cache;
208 break;
209 }
210 n = n->rb_right;
211 } else {
212 ret = cache;
213 break;
214 }
215 }
216 if (ret) {
217 btrfs_get_block_group(ret);
218 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
219 info->first_logical_byte = ret->key.objectid;
220 }
221 spin_unlock(&info->block_group_cache_lock);
222
223 return ret;
224 }
225
226 static int add_excluded_extent(struct btrfs_root *root,
227 u64 start, u64 num_bytes)
228 {
229 u64 end = start + num_bytes - 1;
230 set_extent_bits(&root->fs_info->freed_extents[0],
231 start, end, EXTENT_UPTODATE);
232 set_extent_bits(&root->fs_info->freed_extents[1],
233 start, end, EXTENT_UPTODATE);
234 return 0;
235 }
236
237 static void free_excluded_extents(struct btrfs_root *root,
238 struct btrfs_block_group_cache *cache)
239 {
240 u64 start, end;
241
242 start = cache->key.objectid;
243 end = start + cache->key.offset - 1;
244
245 clear_extent_bits(&root->fs_info->freed_extents[0],
246 start, end, EXTENT_UPTODATE);
247 clear_extent_bits(&root->fs_info->freed_extents[1],
248 start, end, EXTENT_UPTODATE);
249 }
250
251 static int exclude_super_stripes(struct btrfs_root *root,
252 struct btrfs_block_group_cache *cache)
253 {
254 u64 bytenr;
255 u64 *logical;
256 int stripe_len;
257 int i, nr, ret;
258
259 if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
260 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
261 cache->bytes_super += stripe_len;
262 ret = add_excluded_extent(root, cache->key.objectid,
263 stripe_len);
264 if (ret)
265 return ret;
266 }
267
268 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
269 bytenr = btrfs_sb_offset(i);
270 ret = btrfs_rmap_block(root->fs_info, cache->key.objectid,
271 bytenr, 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 return block_group_cache_tree_search(info, bytenr, 0);
734 }
735
736 /*
737 * return the block group that contains the given bytenr
738 */
739 struct btrfs_block_group_cache *btrfs_lookup_block_group(
740 struct btrfs_fs_info *info,
741 u64 bytenr)
742 {
743 return block_group_cache_tree_search(info, bytenr, 1);
744 }
745
746 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
747 u64 flags)
748 {
749 struct list_head *head = &info->space_info;
750 struct btrfs_space_info *found;
751
752 flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
753
754 rcu_read_lock();
755 list_for_each_entry_rcu(found, head, list) {
756 if (found->flags & flags) {
757 rcu_read_unlock();
758 return found;
759 }
760 }
761 rcu_read_unlock();
762 return NULL;
763 }
764
765 /*
766 * after adding space to the filesystem, we need to clear the full flags
767 * on all the space infos.
768 */
769 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
770 {
771 struct list_head *head = &info->space_info;
772 struct btrfs_space_info *found;
773
774 rcu_read_lock();
775 list_for_each_entry_rcu(found, head, list)
776 found->full = 0;
777 rcu_read_unlock();
778 }
779
780 /* simple helper to search for an existing data extent at a given offset */
781 int btrfs_lookup_data_extent(struct btrfs_root *root, u64 start, u64 len)
782 {
783 int ret;
784 struct btrfs_key key;
785 struct btrfs_path *path;
786
787 path = btrfs_alloc_path();
788 if (!path)
789 return -ENOMEM;
790
791 key.objectid = start;
792 key.offset = len;
793 key.type = BTRFS_EXTENT_ITEM_KEY;
794 ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
795 0, 0);
796 btrfs_free_path(path);
797 return ret;
798 }
799
800 /*
801 * helper function to lookup reference count and flags of a tree block.
802 *
803 * the head node for delayed ref is used to store the sum of all the
804 * reference count modifications queued up in the rbtree. the head
805 * node may also store the extent flags to set. This way you can check
806 * to see what the reference count and extent flags would be if all of
807 * the delayed refs are not processed.
808 */
809 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
810 struct btrfs_root *root, u64 bytenr,
811 u64 offset, int metadata, u64 *refs, u64 *flags)
812 {
813 struct btrfs_delayed_ref_head *head;
814 struct btrfs_delayed_ref_root *delayed_refs;
815 struct btrfs_path *path;
816 struct btrfs_extent_item *ei;
817 struct extent_buffer *leaf;
818 struct btrfs_key key;
819 u32 item_size;
820 u64 num_refs;
821 u64 extent_flags;
822 int ret;
823
824 /*
825 * If we don't have skinny metadata, don't bother doing anything
826 * different
827 */
828 if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA)) {
829 offset = root->nodesize;
830 metadata = 0;
831 }
832
833 path = btrfs_alloc_path();
834 if (!path)
835 return -ENOMEM;
836
837 if (!trans) {
838 path->skip_locking = 1;
839 path->search_commit_root = 1;
840 }
841
842 search_again:
843 key.objectid = bytenr;
844 key.offset = offset;
845 if (metadata)
846 key.type = BTRFS_METADATA_ITEM_KEY;
847 else
848 key.type = BTRFS_EXTENT_ITEM_KEY;
849
850 ret = btrfs_search_slot(trans, root->fs_info->extent_root,
851 &key, path, 0, 0);
852 if (ret < 0)
853 goto out_free;
854
855 if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
856 if (path->slots[0]) {
857 path->slots[0]--;
858 btrfs_item_key_to_cpu(path->nodes[0], &key,
859 path->slots[0]);
860 if (key.objectid == bytenr &&
861 key.type == BTRFS_EXTENT_ITEM_KEY &&
862 key.offset == root->nodesize)
863 ret = 0;
864 }
865 }
866
867 if (ret == 0) {
868 leaf = path->nodes[0];
869 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
870 if (item_size >= sizeof(*ei)) {
871 ei = btrfs_item_ptr(leaf, path->slots[0],
872 struct btrfs_extent_item);
873 num_refs = btrfs_extent_refs(leaf, ei);
874 extent_flags = btrfs_extent_flags(leaf, ei);
875 } else {
876 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
877 struct btrfs_extent_item_v0 *ei0;
878 BUG_ON(item_size != sizeof(*ei0));
879 ei0 = btrfs_item_ptr(leaf, path->slots[0],
880 struct btrfs_extent_item_v0);
881 num_refs = btrfs_extent_refs_v0(leaf, ei0);
882 /* FIXME: this isn't correct for data */
883 extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
884 #else
885 BUG();
886 #endif
887 }
888 BUG_ON(num_refs == 0);
889 } else {
890 num_refs = 0;
891 extent_flags = 0;
892 ret = 0;
893 }
894
895 if (!trans)
896 goto out;
897
898 delayed_refs = &trans->transaction->delayed_refs;
899 spin_lock(&delayed_refs->lock);
900 head = btrfs_find_delayed_ref_head(trans, bytenr);
901 if (head) {
902 if (!mutex_trylock(&head->mutex)) {
903 atomic_inc(&head->node.refs);
904 spin_unlock(&delayed_refs->lock);
905
906 btrfs_release_path(path);
907
908 /*
909 * Mutex was contended, block until it's released and try
910 * again
911 */
912 mutex_lock(&head->mutex);
913 mutex_unlock(&head->mutex);
914 btrfs_put_delayed_ref(&head->node);
915 goto search_again;
916 }
917 spin_lock(&head->lock);
918 if (head->extent_op && head->extent_op->update_flags)
919 extent_flags |= head->extent_op->flags_to_set;
920 else
921 BUG_ON(num_refs == 0);
922
923 num_refs += head->node.ref_mod;
924 spin_unlock(&head->lock);
925 mutex_unlock(&head->mutex);
926 }
927 spin_unlock(&delayed_refs->lock);
928 out:
929 WARN_ON(num_refs == 0);
930 if (refs)
931 *refs = num_refs;
932 if (flags)
933 *flags = extent_flags;
934 out_free:
935 btrfs_free_path(path);
936 return ret;
937 }
938
939 /*
940 * Back reference rules. Back refs have three main goals:
941 *
942 * 1) differentiate between all holders of references to an extent so that
943 * when a reference is dropped we can make sure it was a valid reference
944 * before freeing the extent.
945 *
946 * 2) Provide enough information to quickly find the holders of an extent
947 * if we notice a given block is corrupted or bad.
948 *
949 * 3) Make it easy to migrate blocks for FS shrinking or storage pool
950 * maintenance. This is actually the same as #2, but with a slightly
951 * different use case.
952 *
953 * There are two kinds of back refs. The implicit back refs is optimized
954 * for pointers in non-shared tree blocks. For a given pointer in a block,
955 * back refs of this kind provide information about the block's owner tree
956 * and the pointer's key. These information allow us to find the block by
957 * b-tree searching. The full back refs is for pointers in tree blocks not
958 * referenced by their owner trees. The location of tree block is recorded
959 * in the back refs. Actually the full back refs is generic, and can be
960 * used in all cases the implicit back refs is used. The major shortcoming
961 * of the full back refs is its overhead. Every time a tree block gets
962 * COWed, we have to update back refs entry for all pointers in it.
963 *
964 * For a newly allocated tree block, we use implicit back refs for
965 * pointers in it. This means most tree related operations only involve
966 * implicit back refs. For a tree block created in old transaction, the
967 * only way to drop a reference to it is COW it. So we can detect the
968 * event that tree block loses its owner tree's reference and do the
969 * back refs conversion.
970 *
971 * When a tree block is COWed through a tree, there are four cases:
972 *
973 * The reference count of the block is one and the tree is the block's
974 * owner tree. Nothing to do in this case.
975 *
976 * The reference count of the block is one and the tree is not the
977 * block's owner tree. In this case, full back refs is used for pointers
978 * in the block. Remove these full back refs, add implicit back refs for
979 * every pointers in the new block.
980 *
981 * The reference count of the block is greater than one and the tree is
982 * the block's owner tree. In this case, implicit back refs is used for
983 * pointers in the block. Add full back refs for every pointers in the
984 * block, increase lower level extents' reference counts. The original
985 * implicit back refs are entailed to the new block.
986 *
987 * The reference count of the block is greater than one and the tree is
988 * not the block's owner tree. Add implicit back refs for every pointer in
989 * the new block, increase lower level extents' reference count.
990 *
991 * Back Reference Key composing:
992 *
993 * The key objectid corresponds to the first byte in the extent,
994 * The key type is used to differentiate between types of back refs.
995 * There are different meanings of the key offset for different types
996 * of back refs.
997 *
998 * File extents can be referenced by:
999 *
1000 * - multiple snapshots, subvolumes, or different generations in one subvol
1001 * - different files inside a single subvolume
1002 * - different offsets inside a file (bookend extents in file.c)
1003 *
1004 * The extent ref structure for the implicit back refs has fields for:
1005 *
1006 * - Objectid of the subvolume root
1007 * - objectid of the file holding the reference
1008 * - original offset in the file
1009 * - how many bookend extents
1010 *
1011 * The key offset for the implicit back refs is hash of the first
1012 * three fields.
1013 *
1014 * The extent ref structure for the full back refs has field for:
1015 *
1016 * - number of pointers in the tree leaf
1017 *
1018 * The key offset for the implicit back refs is the first byte of
1019 * the tree leaf
1020 *
1021 * When a file extent is allocated, The implicit back refs is used.
1022 * the fields are filled in:
1023 *
1024 * (root_key.objectid, inode objectid, offset in file, 1)
1025 *
1026 * When a file extent is removed file truncation, we find the
1027 * corresponding implicit back refs and check the following fields:
1028 *
1029 * (btrfs_header_owner(leaf), inode objectid, offset in file)
1030 *
1031 * Btree extents can be referenced by:
1032 *
1033 * - Different subvolumes
1034 *
1035 * Both the implicit back refs and the full back refs for tree blocks
1036 * only consist of key. The key offset for the implicit back refs is
1037 * objectid of block's owner tree. The key offset for the full back refs
1038 * is the first byte of parent block.
1039 *
1040 * When implicit back refs is used, information about the lowest key and
1041 * level of the tree block are required. These information are stored in
1042 * tree block info structure.
1043 */
1044
1045 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1046 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
1047 struct btrfs_root *root,
1048 struct btrfs_path *path,
1049 u64 owner, u32 extra_size)
1050 {
1051 struct btrfs_extent_item *item;
1052 struct btrfs_extent_item_v0 *ei0;
1053 struct btrfs_extent_ref_v0 *ref0;
1054 struct btrfs_tree_block_info *bi;
1055 struct extent_buffer *leaf;
1056 struct btrfs_key key;
1057 struct btrfs_key found_key;
1058 u32 new_size = sizeof(*item);
1059 u64 refs;
1060 int ret;
1061
1062 leaf = path->nodes[0];
1063 BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
1064
1065 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1066 ei0 = btrfs_item_ptr(leaf, path->slots[0],
1067 struct btrfs_extent_item_v0);
1068 refs = btrfs_extent_refs_v0(leaf, ei0);
1069
1070 if (owner == (u64)-1) {
1071 while (1) {
1072 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1073 ret = btrfs_next_leaf(root, path);
1074 if (ret < 0)
1075 return ret;
1076 BUG_ON(ret > 0); /* Corruption */
1077 leaf = path->nodes[0];
1078 }
1079 btrfs_item_key_to_cpu(leaf, &found_key,
1080 path->slots[0]);
1081 BUG_ON(key.objectid != found_key.objectid);
1082 if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
1083 path->slots[0]++;
1084 continue;
1085 }
1086 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1087 struct btrfs_extent_ref_v0);
1088 owner = btrfs_ref_objectid_v0(leaf, ref0);
1089 break;
1090 }
1091 }
1092 btrfs_release_path(path);
1093
1094 if (owner < BTRFS_FIRST_FREE_OBJECTID)
1095 new_size += sizeof(*bi);
1096
1097 new_size -= sizeof(*ei0);
1098 ret = btrfs_search_slot(trans, root, &key, path,
1099 new_size + extra_size, 1);
1100 if (ret < 0)
1101 return ret;
1102 BUG_ON(ret); /* Corruption */
1103
1104 btrfs_extend_item(root, path, new_size);
1105
1106 leaf = path->nodes[0];
1107 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1108 btrfs_set_extent_refs(leaf, item, refs);
1109 /* FIXME: get real generation */
1110 btrfs_set_extent_generation(leaf, item, 0);
1111 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1112 btrfs_set_extent_flags(leaf, item,
1113 BTRFS_EXTENT_FLAG_TREE_BLOCK |
1114 BTRFS_BLOCK_FLAG_FULL_BACKREF);
1115 bi = (struct btrfs_tree_block_info *)(item + 1);
1116 /* FIXME: get first key of the block */
1117 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1118 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1119 } else {
1120 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1121 }
1122 btrfs_mark_buffer_dirty(leaf);
1123 return 0;
1124 }
1125 #endif
1126
1127 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1128 {
1129 u32 high_crc = ~(u32)0;
1130 u32 low_crc = ~(u32)0;
1131 __le64 lenum;
1132
1133 lenum = cpu_to_le64(root_objectid);
1134 high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
1135 lenum = cpu_to_le64(owner);
1136 low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1137 lenum = cpu_to_le64(offset);
1138 low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1139
1140 return ((u64)high_crc << 31) ^ (u64)low_crc;
1141 }
1142
1143 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1144 struct btrfs_extent_data_ref *ref)
1145 {
1146 return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1147 btrfs_extent_data_ref_objectid(leaf, ref),
1148 btrfs_extent_data_ref_offset(leaf, ref));
1149 }
1150
1151 static int match_extent_data_ref(struct extent_buffer *leaf,
1152 struct btrfs_extent_data_ref *ref,
1153 u64 root_objectid, u64 owner, u64 offset)
1154 {
1155 if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1156 btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1157 btrfs_extent_data_ref_offset(leaf, ref) != offset)
1158 return 0;
1159 return 1;
1160 }
1161
1162 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1163 struct btrfs_root *root,
1164 struct btrfs_path *path,
1165 u64 bytenr, u64 parent,
1166 u64 root_objectid,
1167 u64 owner, u64 offset)
1168 {
1169 struct btrfs_key key;
1170 struct btrfs_extent_data_ref *ref;
1171 struct extent_buffer *leaf;
1172 u32 nritems;
1173 int ret;
1174 int recow;
1175 int err = -ENOENT;
1176
1177 key.objectid = bytenr;
1178 if (parent) {
1179 key.type = BTRFS_SHARED_DATA_REF_KEY;
1180 key.offset = parent;
1181 } else {
1182 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1183 key.offset = hash_extent_data_ref(root_objectid,
1184 owner, offset);
1185 }
1186 again:
1187 recow = 0;
1188 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1189 if (ret < 0) {
1190 err = ret;
1191 goto fail;
1192 }
1193
1194 if (parent) {
1195 if (!ret)
1196 return 0;
1197 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1198 key.type = BTRFS_EXTENT_REF_V0_KEY;
1199 btrfs_release_path(path);
1200 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1201 if (ret < 0) {
1202 err = ret;
1203 goto fail;
1204 }
1205 if (!ret)
1206 return 0;
1207 #endif
1208 goto fail;
1209 }
1210
1211 leaf = path->nodes[0];
1212 nritems = btrfs_header_nritems(leaf);
1213 while (1) {
1214 if (path->slots[0] >= nritems) {
1215 ret = btrfs_next_leaf(root, path);
1216 if (ret < 0)
1217 err = ret;
1218 if (ret)
1219 goto fail;
1220
1221 leaf = path->nodes[0];
1222 nritems = btrfs_header_nritems(leaf);
1223 recow = 1;
1224 }
1225
1226 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1227 if (key.objectid != bytenr ||
1228 key.type != BTRFS_EXTENT_DATA_REF_KEY)
1229 goto fail;
1230
1231 ref = btrfs_item_ptr(leaf, path->slots[0],
1232 struct btrfs_extent_data_ref);
1233
1234 if (match_extent_data_ref(leaf, ref, root_objectid,
1235 owner, offset)) {
1236 if (recow) {
1237 btrfs_release_path(path);
1238 goto again;
1239 }
1240 err = 0;
1241 break;
1242 }
1243 path->slots[0]++;
1244 }
1245 fail:
1246 return err;
1247 }
1248
1249 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1250 struct btrfs_root *root,
1251 struct btrfs_path *path,
1252 u64 bytenr, u64 parent,
1253 u64 root_objectid, u64 owner,
1254 u64 offset, int refs_to_add)
1255 {
1256 struct btrfs_key key;
1257 struct extent_buffer *leaf;
1258 u32 size;
1259 u32 num_refs;
1260 int ret;
1261
1262 key.objectid = bytenr;
1263 if (parent) {
1264 key.type = BTRFS_SHARED_DATA_REF_KEY;
1265 key.offset = parent;
1266 size = sizeof(struct btrfs_shared_data_ref);
1267 } else {
1268 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1269 key.offset = hash_extent_data_ref(root_objectid,
1270 owner, offset);
1271 size = sizeof(struct btrfs_extent_data_ref);
1272 }
1273
1274 ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1275 if (ret && ret != -EEXIST)
1276 goto fail;
1277
1278 leaf = path->nodes[0];
1279 if (parent) {
1280 struct btrfs_shared_data_ref *ref;
1281 ref = btrfs_item_ptr(leaf, path->slots[0],
1282 struct btrfs_shared_data_ref);
1283 if (ret == 0) {
1284 btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1285 } else {
1286 num_refs = btrfs_shared_data_ref_count(leaf, ref);
1287 num_refs += refs_to_add;
1288 btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1289 }
1290 } else {
1291 struct btrfs_extent_data_ref *ref;
1292 while (ret == -EEXIST) {
1293 ref = btrfs_item_ptr(leaf, path->slots[0],
1294 struct btrfs_extent_data_ref);
1295 if (match_extent_data_ref(leaf, ref, root_objectid,
1296 owner, offset))
1297 break;
1298 btrfs_release_path(path);
1299 key.offset++;
1300 ret = btrfs_insert_empty_item(trans, root, path, &key,
1301 size);
1302 if (ret && ret != -EEXIST)
1303 goto fail;
1304
1305 leaf = path->nodes[0];
1306 }
1307 ref = btrfs_item_ptr(leaf, path->slots[0],
1308 struct btrfs_extent_data_ref);
1309 if (ret == 0) {
1310 btrfs_set_extent_data_ref_root(leaf, ref,
1311 root_objectid);
1312 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1313 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1314 btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1315 } else {
1316 num_refs = btrfs_extent_data_ref_count(leaf, ref);
1317 num_refs += refs_to_add;
1318 btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1319 }
1320 }
1321 btrfs_mark_buffer_dirty(leaf);
1322 ret = 0;
1323 fail:
1324 btrfs_release_path(path);
1325 return ret;
1326 }
1327
1328 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1329 struct btrfs_root *root,
1330 struct btrfs_path *path,
1331 int refs_to_drop, int *last_ref)
1332 {
1333 struct btrfs_key key;
1334 struct btrfs_extent_data_ref *ref1 = NULL;
1335 struct btrfs_shared_data_ref *ref2 = NULL;
1336 struct extent_buffer *leaf;
1337 u32 num_refs = 0;
1338 int ret = 0;
1339
1340 leaf = path->nodes[0];
1341 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1342
1343 if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1344 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1345 struct btrfs_extent_data_ref);
1346 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1347 } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1348 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1349 struct btrfs_shared_data_ref);
1350 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1351 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1352 } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1353 struct btrfs_extent_ref_v0 *ref0;
1354 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1355 struct btrfs_extent_ref_v0);
1356 num_refs = btrfs_ref_count_v0(leaf, ref0);
1357 #endif
1358 } else {
1359 BUG();
1360 }
1361
1362 BUG_ON(num_refs < refs_to_drop);
1363 num_refs -= refs_to_drop;
1364
1365 if (num_refs == 0) {
1366 ret = btrfs_del_item(trans, root, path);
1367 *last_ref = 1;
1368 } else {
1369 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1370 btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1371 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1372 btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1373 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1374 else {
1375 struct btrfs_extent_ref_v0 *ref0;
1376 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1377 struct btrfs_extent_ref_v0);
1378 btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1379 }
1380 #endif
1381 btrfs_mark_buffer_dirty(leaf);
1382 }
1383 return ret;
1384 }
1385
1386 static noinline u32 extent_data_ref_count(struct btrfs_path *path,
1387 struct btrfs_extent_inline_ref *iref)
1388 {
1389 struct btrfs_key key;
1390 struct extent_buffer *leaf;
1391 struct btrfs_extent_data_ref *ref1;
1392 struct btrfs_shared_data_ref *ref2;
1393 u32 num_refs = 0;
1394
1395 leaf = path->nodes[0];
1396 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1397 if (iref) {
1398 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1399 BTRFS_EXTENT_DATA_REF_KEY) {
1400 ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1401 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1402 } else {
1403 ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1404 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1405 }
1406 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1407 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1408 struct btrfs_extent_data_ref);
1409 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1410 } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1411 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1412 struct btrfs_shared_data_ref);
1413 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1414 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1415 } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1416 struct btrfs_extent_ref_v0 *ref0;
1417 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1418 struct btrfs_extent_ref_v0);
1419 num_refs = btrfs_ref_count_v0(leaf, ref0);
1420 #endif
1421 } else {
1422 WARN_ON(1);
1423 }
1424 return num_refs;
1425 }
1426
1427 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1428 struct btrfs_root *root,
1429 struct btrfs_path *path,
1430 u64 bytenr, u64 parent,
1431 u64 root_objectid)
1432 {
1433 struct btrfs_key key;
1434 int ret;
1435
1436 key.objectid = bytenr;
1437 if (parent) {
1438 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1439 key.offset = parent;
1440 } else {
1441 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1442 key.offset = root_objectid;
1443 }
1444
1445 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1446 if (ret > 0)
1447 ret = -ENOENT;
1448 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1449 if (ret == -ENOENT && parent) {
1450 btrfs_release_path(path);
1451 key.type = BTRFS_EXTENT_REF_V0_KEY;
1452 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1453 if (ret > 0)
1454 ret = -ENOENT;
1455 }
1456 #endif
1457 return ret;
1458 }
1459
1460 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1461 struct btrfs_root *root,
1462 struct btrfs_path *path,
1463 u64 bytenr, u64 parent,
1464 u64 root_objectid)
1465 {
1466 struct btrfs_key key;
1467 int ret;
1468
1469 key.objectid = bytenr;
1470 if (parent) {
1471 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1472 key.offset = parent;
1473 } else {
1474 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1475 key.offset = root_objectid;
1476 }
1477
1478 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1479 btrfs_release_path(path);
1480 return ret;
1481 }
1482
1483 static inline int extent_ref_type(u64 parent, u64 owner)
1484 {
1485 int type;
1486 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1487 if (parent > 0)
1488 type = BTRFS_SHARED_BLOCK_REF_KEY;
1489 else
1490 type = BTRFS_TREE_BLOCK_REF_KEY;
1491 } else {
1492 if (parent > 0)
1493 type = BTRFS_SHARED_DATA_REF_KEY;
1494 else
1495 type = BTRFS_EXTENT_DATA_REF_KEY;
1496 }
1497 return type;
1498 }
1499
1500 static int find_next_key(struct btrfs_path *path, int level,
1501 struct btrfs_key *key)
1502
1503 {
1504 for (; level < BTRFS_MAX_LEVEL; level++) {
1505 if (!path->nodes[level])
1506 break;
1507 if (path->slots[level] + 1 >=
1508 btrfs_header_nritems(path->nodes[level]))
1509 continue;
1510 if (level == 0)
1511 btrfs_item_key_to_cpu(path->nodes[level], key,
1512 path->slots[level] + 1);
1513 else
1514 btrfs_node_key_to_cpu(path->nodes[level], key,
1515 path->slots[level] + 1);
1516 return 0;
1517 }
1518 return 1;
1519 }
1520
1521 /*
1522 * look for inline back ref. if back ref is found, *ref_ret is set
1523 * to the address of inline back ref, and 0 is returned.
1524 *
1525 * if back ref isn't found, *ref_ret is set to the address where it
1526 * should be inserted, and -ENOENT is returned.
1527 *
1528 * if insert is true and there are too many inline back refs, the path
1529 * points to the extent item, and -EAGAIN is returned.
1530 *
1531 * NOTE: inline back refs are ordered in the same way that back ref
1532 * items in the tree are ordered.
1533 */
1534 static noinline_for_stack
1535 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1536 struct btrfs_root *root,
1537 struct btrfs_path *path,
1538 struct btrfs_extent_inline_ref **ref_ret,
1539 u64 bytenr, u64 num_bytes,
1540 u64 parent, u64 root_objectid,
1541 u64 owner, u64 offset, int insert)
1542 {
1543 struct btrfs_key key;
1544 struct extent_buffer *leaf;
1545 struct btrfs_extent_item *ei;
1546 struct btrfs_extent_inline_ref *iref;
1547 u64 flags;
1548 u64 item_size;
1549 unsigned long ptr;
1550 unsigned long end;
1551 int extra_size;
1552 int type;
1553 int want;
1554 int ret;
1555 int err = 0;
1556 bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
1557 SKINNY_METADATA);
1558
1559 key.objectid = bytenr;
1560 key.type = BTRFS_EXTENT_ITEM_KEY;
1561 key.offset = num_bytes;
1562
1563 want = extent_ref_type(parent, owner);
1564 if (insert) {
1565 extra_size = btrfs_extent_inline_ref_size(want);
1566 path->keep_locks = 1;
1567 } else
1568 extra_size = -1;
1569
1570 /*
1571 * Owner is our parent level, so we can just add one to get the level
1572 * for the block we are interested in.
1573 */
1574 if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1575 key.type = BTRFS_METADATA_ITEM_KEY;
1576 key.offset = owner;
1577 }
1578
1579 again:
1580 ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1581 if (ret < 0) {
1582 err = ret;
1583 goto out;
1584 }
1585
1586 /*
1587 * We may be a newly converted file system which still has the old fat
1588 * extent entries for metadata, so try and see if we have one of those.
1589 */
1590 if (ret > 0 && skinny_metadata) {
1591 skinny_metadata = false;
1592 if (path->slots[0]) {
1593 path->slots[0]--;
1594 btrfs_item_key_to_cpu(path->nodes[0], &key,
1595 path->slots[0]);
1596 if (key.objectid == bytenr &&
1597 key.type == BTRFS_EXTENT_ITEM_KEY &&
1598 key.offset == num_bytes)
1599 ret = 0;
1600 }
1601 if (ret) {
1602 key.objectid = bytenr;
1603 key.type = BTRFS_EXTENT_ITEM_KEY;
1604 key.offset = num_bytes;
1605 btrfs_release_path(path);
1606 goto again;
1607 }
1608 }
1609
1610 if (ret && !insert) {
1611 err = -ENOENT;
1612 goto out;
1613 } else if (WARN_ON(ret)) {
1614 err = -EIO;
1615 goto out;
1616 }
1617
1618 leaf = path->nodes[0];
1619 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1620 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1621 if (item_size < sizeof(*ei)) {
1622 if (!insert) {
1623 err = -ENOENT;
1624 goto out;
1625 }
1626 ret = convert_extent_item_v0(trans, root, path, owner,
1627 extra_size);
1628 if (ret < 0) {
1629 err = ret;
1630 goto out;
1631 }
1632 leaf = path->nodes[0];
1633 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1634 }
1635 #endif
1636 BUG_ON(item_size < sizeof(*ei));
1637
1638 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1639 flags = btrfs_extent_flags(leaf, ei);
1640
1641 ptr = (unsigned long)(ei + 1);
1642 end = (unsigned long)ei + item_size;
1643
1644 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1645 ptr += sizeof(struct btrfs_tree_block_info);
1646 BUG_ON(ptr > end);
1647 }
1648
1649 err = -ENOENT;
1650 while (1) {
1651 if (ptr >= end) {
1652 WARN_ON(ptr > end);
1653 break;
1654 }
1655 iref = (struct btrfs_extent_inline_ref *)ptr;
1656 type = btrfs_extent_inline_ref_type(leaf, iref);
1657 if (want < type)
1658 break;
1659 if (want > type) {
1660 ptr += btrfs_extent_inline_ref_size(type);
1661 continue;
1662 }
1663
1664 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1665 struct btrfs_extent_data_ref *dref;
1666 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1667 if (match_extent_data_ref(leaf, dref, root_objectid,
1668 owner, offset)) {
1669 err = 0;
1670 break;
1671 }
1672 if (hash_extent_data_ref_item(leaf, dref) <
1673 hash_extent_data_ref(root_objectid, owner, offset))
1674 break;
1675 } else {
1676 u64 ref_offset;
1677 ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1678 if (parent > 0) {
1679 if (parent == ref_offset) {
1680 err = 0;
1681 break;
1682 }
1683 if (ref_offset < parent)
1684 break;
1685 } else {
1686 if (root_objectid == ref_offset) {
1687 err = 0;
1688 break;
1689 }
1690 if (ref_offset < root_objectid)
1691 break;
1692 }
1693 }
1694 ptr += btrfs_extent_inline_ref_size(type);
1695 }
1696 if (err == -ENOENT && insert) {
1697 if (item_size + extra_size >=
1698 BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1699 err = -EAGAIN;
1700 goto out;
1701 }
1702 /*
1703 * To add new inline back ref, we have to make sure
1704 * there is no corresponding back ref item.
1705 * For simplicity, we just do not add new inline back
1706 * ref if there is any kind of item for this block
1707 */
1708 if (find_next_key(path, 0, &key) == 0 &&
1709 key.objectid == bytenr &&
1710 key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1711 err = -EAGAIN;
1712 goto out;
1713 }
1714 }
1715 *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1716 out:
1717 if (insert) {
1718 path->keep_locks = 0;
1719 btrfs_unlock_up_safe(path, 1);
1720 }
1721 return err;
1722 }
1723
1724 /*
1725 * helper to add new inline back ref
1726 */
1727 static noinline_for_stack
1728 void setup_inline_extent_backref(struct btrfs_root *root,
1729 struct btrfs_path *path,
1730 struct btrfs_extent_inline_ref *iref,
1731 u64 parent, u64 root_objectid,
1732 u64 owner, u64 offset, int refs_to_add,
1733 struct btrfs_delayed_extent_op *extent_op)
1734 {
1735 struct extent_buffer *leaf;
1736 struct btrfs_extent_item *ei;
1737 unsigned long ptr;
1738 unsigned long end;
1739 unsigned long item_offset;
1740 u64 refs;
1741 int size;
1742 int type;
1743
1744 leaf = path->nodes[0];
1745 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1746 item_offset = (unsigned long)iref - (unsigned long)ei;
1747
1748 type = extent_ref_type(parent, owner);
1749 size = btrfs_extent_inline_ref_size(type);
1750
1751 btrfs_extend_item(root, path, size);
1752
1753 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1754 refs = btrfs_extent_refs(leaf, ei);
1755 refs += refs_to_add;
1756 btrfs_set_extent_refs(leaf, ei, refs);
1757 if (extent_op)
1758 __run_delayed_extent_op(extent_op, leaf, ei);
1759
1760 ptr = (unsigned long)ei + item_offset;
1761 end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1762 if (ptr < end - size)
1763 memmove_extent_buffer(leaf, ptr + size, ptr,
1764 end - size - ptr);
1765
1766 iref = (struct btrfs_extent_inline_ref *)ptr;
1767 btrfs_set_extent_inline_ref_type(leaf, iref, type);
1768 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1769 struct btrfs_extent_data_ref *dref;
1770 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1771 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1772 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1773 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1774 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1775 } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1776 struct btrfs_shared_data_ref *sref;
1777 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1778 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1779 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1780 } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1781 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1782 } else {
1783 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1784 }
1785 btrfs_mark_buffer_dirty(leaf);
1786 }
1787
1788 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1789 struct btrfs_root *root,
1790 struct btrfs_path *path,
1791 struct btrfs_extent_inline_ref **ref_ret,
1792 u64 bytenr, u64 num_bytes, u64 parent,
1793 u64 root_objectid, u64 owner, u64 offset)
1794 {
1795 int ret;
1796
1797 ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1798 bytenr, num_bytes, parent,
1799 root_objectid, owner, offset, 0);
1800 if (ret != -ENOENT)
1801 return ret;
1802
1803 btrfs_release_path(path);
1804 *ref_ret = NULL;
1805
1806 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1807 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1808 root_objectid);
1809 } else {
1810 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1811 root_objectid, owner, offset);
1812 }
1813 return ret;
1814 }
1815
1816 /*
1817 * helper to update/remove inline back ref
1818 */
1819 static noinline_for_stack
1820 void update_inline_extent_backref(struct btrfs_root *root,
1821 struct btrfs_path *path,
1822 struct btrfs_extent_inline_ref *iref,
1823 int refs_to_mod,
1824 struct btrfs_delayed_extent_op *extent_op,
1825 int *last_ref)
1826 {
1827 struct extent_buffer *leaf;
1828 struct btrfs_extent_item *ei;
1829 struct btrfs_extent_data_ref *dref = NULL;
1830 struct btrfs_shared_data_ref *sref = NULL;
1831 unsigned long ptr;
1832 unsigned long end;
1833 u32 item_size;
1834 int size;
1835 int type;
1836 u64 refs;
1837
1838 leaf = path->nodes[0];
1839 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1840 refs = btrfs_extent_refs(leaf, ei);
1841 WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1842 refs += refs_to_mod;
1843 btrfs_set_extent_refs(leaf, ei, refs);
1844 if (extent_op)
1845 __run_delayed_extent_op(extent_op, leaf, ei);
1846
1847 type = btrfs_extent_inline_ref_type(leaf, iref);
1848
1849 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1850 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1851 refs = btrfs_extent_data_ref_count(leaf, dref);
1852 } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1853 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1854 refs = btrfs_shared_data_ref_count(leaf, sref);
1855 } else {
1856 refs = 1;
1857 BUG_ON(refs_to_mod != -1);
1858 }
1859
1860 BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1861 refs += refs_to_mod;
1862
1863 if (refs > 0) {
1864 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1865 btrfs_set_extent_data_ref_count(leaf, dref, refs);
1866 else
1867 btrfs_set_shared_data_ref_count(leaf, sref, refs);
1868 } else {
1869 *last_ref = 1;
1870 size = btrfs_extent_inline_ref_size(type);
1871 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1872 ptr = (unsigned long)iref;
1873 end = (unsigned long)ei + item_size;
1874 if (ptr + size < end)
1875 memmove_extent_buffer(leaf, ptr, ptr + size,
1876 end - ptr - size);
1877 item_size -= size;
1878 btrfs_truncate_item(root, path, item_size, 1);
1879 }
1880 btrfs_mark_buffer_dirty(leaf);
1881 }
1882
1883 static noinline_for_stack
1884 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1885 struct btrfs_root *root,
1886 struct btrfs_path *path,
1887 u64 bytenr, u64 num_bytes, u64 parent,
1888 u64 root_objectid, u64 owner,
1889 u64 offset, int refs_to_add,
1890 struct btrfs_delayed_extent_op *extent_op)
1891 {
1892 struct btrfs_extent_inline_ref *iref;
1893 int ret;
1894
1895 ret = lookup_inline_extent_backref(trans, root, path, &iref,
1896 bytenr, num_bytes, parent,
1897 root_objectid, owner, offset, 1);
1898 if (ret == 0) {
1899 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1900 update_inline_extent_backref(root, path, iref,
1901 refs_to_add, extent_op, NULL);
1902 } else if (ret == -ENOENT) {
1903 setup_inline_extent_backref(root, path, iref, parent,
1904 root_objectid, owner, offset,
1905 refs_to_add, extent_op);
1906 ret = 0;
1907 }
1908 return ret;
1909 }
1910
1911 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1912 struct btrfs_root *root,
1913 struct btrfs_path *path,
1914 u64 bytenr, u64 parent, u64 root_objectid,
1915 u64 owner, u64 offset, int refs_to_add)
1916 {
1917 int ret;
1918 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1919 BUG_ON(refs_to_add != 1);
1920 ret = insert_tree_block_ref(trans, root, path, bytenr,
1921 parent, root_objectid);
1922 } else {
1923 ret = insert_extent_data_ref(trans, root, path, bytenr,
1924 parent, root_objectid,
1925 owner, offset, refs_to_add);
1926 }
1927 return ret;
1928 }
1929
1930 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1931 struct btrfs_root *root,
1932 struct btrfs_path *path,
1933 struct btrfs_extent_inline_ref *iref,
1934 int refs_to_drop, int is_data, int *last_ref)
1935 {
1936 int ret = 0;
1937
1938 BUG_ON(!is_data && refs_to_drop != 1);
1939 if (iref) {
1940 update_inline_extent_backref(root, path, iref,
1941 -refs_to_drop, NULL, last_ref);
1942 } else if (is_data) {
1943 ret = remove_extent_data_ref(trans, root, path, refs_to_drop,
1944 last_ref);
1945 } else {
1946 *last_ref = 1;
1947 ret = btrfs_del_item(trans, root, path);
1948 }
1949 return ret;
1950 }
1951
1952 #define in_range(b, first, len) ((b) >= (first) && (b) < (first) + (len))
1953 static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
1954 u64 *discarded_bytes)
1955 {
1956 int j, ret = 0;
1957 u64 bytes_left, end;
1958 u64 aligned_start = ALIGN(start, 1 << 9);
1959
1960 if (WARN_ON(start != aligned_start)) {
1961 len -= aligned_start - start;
1962 len = round_down(len, 1 << 9);
1963 start = aligned_start;
1964 }
1965
1966 *discarded_bytes = 0;
1967
1968 if (!len)
1969 return 0;
1970
1971 end = start + len;
1972 bytes_left = len;
1973
1974 /* Skip any superblocks on this device. */
1975 for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
1976 u64 sb_start = btrfs_sb_offset(j);
1977 u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
1978 u64 size = sb_start - start;
1979
1980 if (!in_range(sb_start, start, bytes_left) &&
1981 !in_range(sb_end, start, bytes_left) &&
1982 !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
1983 continue;
1984
1985 /*
1986 * Superblock spans beginning of range. Adjust start and
1987 * try again.
1988 */
1989 if (sb_start <= start) {
1990 start += sb_end - start;
1991 if (start > end) {
1992 bytes_left = 0;
1993 break;
1994 }
1995 bytes_left = end - start;
1996 continue;
1997 }
1998
1999 if (size) {
2000 ret = blkdev_issue_discard(bdev, start >> 9, size >> 9,
2001 GFP_NOFS, 0);
2002 if (!ret)
2003 *discarded_bytes += size;
2004 else if (ret != -EOPNOTSUPP)
2005 return ret;
2006 }
2007
2008 start = sb_end;
2009 if (start > end) {
2010 bytes_left = 0;
2011 break;
2012 }
2013 bytes_left = end - start;
2014 }
2015
2016 if (bytes_left) {
2017 ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9,
2018 GFP_NOFS, 0);
2019 if (!ret)
2020 *discarded_bytes += bytes_left;
2021 }
2022 return ret;
2023 }
2024
2025 int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
2026 u64 num_bytes, u64 *actual_bytes)
2027 {
2028 int ret;
2029 u64 discarded_bytes = 0;
2030 struct btrfs_bio *bbio = NULL;
2031
2032
2033 /*
2034 * Avoid races with device replace and make sure our bbio has devices
2035 * associated to its stripes that don't go away while we are discarding.
2036 */
2037 btrfs_bio_counter_inc_blocked(root->fs_info);
2038 /* Tell the block device(s) that the sectors can be discarded */
2039 ret = btrfs_map_block(root->fs_info, REQ_OP_DISCARD,
2040 bytenr, &num_bytes, &bbio, 0);
2041 /* Error condition is -ENOMEM */
2042 if (!ret) {
2043 struct btrfs_bio_stripe *stripe = bbio->stripes;
2044 int i;
2045
2046
2047 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
2048 u64 bytes;
2049 if (!stripe->dev->can_discard)
2050 continue;
2051
2052 ret = btrfs_issue_discard(stripe->dev->bdev,
2053 stripe->physical,
2054 stripe->length,
2055 &bytes);
2056 if (!ret)
2057 discarded_bytes += bytes;
2058 else if (ret != -EOPNOTSUPP)
2059 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
2060
2061 /*
2062 * Just in case we get back EOPNOTSUPP for some reason,
2063 * just ignore the return value so we don't screw up
2064 * people calling discard_extent.
2065 */
2066 ret = 0;
2067 }
2068 btrfs_put_bbio(bbio);
2069 }
2070 btrfs_bio_counter_dec(root->fs_info);
2071
2072 if (actual_bytes)
2073 *actual_bytes = discarded_bytes;
2074
2075
2076 if (ret == -EOPNOTSUPP)
2077 ret = 0;
2078 return ret;
2079 }
2080
2081 /* Can return -ENOMEM */
2082 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2083 struct btrfs_root *root,
2084 u64 bytenr, u64 num_bytes, u64 parent,
2085 u64 root_objectid, u64 owner, u64 offset)
2086 {
2087 int ret;
2088 struct btrfs_fs_info *fs_info = root->fs_info;
2089
2090 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
2091 root_objectid == BTRFS_TREE_LOG_OBJECTID);
2092
2093 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
2094 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
2095 num_bytes,
2096 parent, root_objectid, (int)owner,
2097 BTRFS_ADD_DELAYED_REF, NULL);
2098 } else {
2099 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
2100 num_bytes, parent, root_objectid,
2101 owner, offset, 0,
2102 BTRFS_ADD_DELAYED_REF, NULL);
2103 }
2104 return ret;
2105 }
2106
2107 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2108 struct btrfs_root *root,
2109 struct btrfs_delayed_ref_node *node,
2110 u64 parent, u64 root_objectid,
2111 u64 owner, u64 offset, int refs_to_add,
2112 struct btrfs_delayed_extent_op *extent_op)
2113 {
2114 struct btrfs_fs_info *fs_info = root->fs_info;
2115 struct btrfs_path *path;
2116 struct extent_buffer *leaf;
2117 struct btrfs_extent_item *item;
2118 struct btrfs_key key;
2119 u64 bytenr = node->bytenr;
2120 u64 num_bytes = node->num_bytes;
2121 u64 refs;
2122 int ret;
2123
2124 path = btrfs_alloc_path();
2125 if (!path)
2126 return -ENOMEM;
2127
2128 path->reada = READA_FORWARD;
2129 path->leave_spinning = 1;
2130 /* this will setup the path even if it fails to insert the back ref */
2131 ret = insert_inline_extent_backref(trans, fs_info->extent_root, path,
2132 bytenr, num_bytes, parent,
2133 root_objectid, owner, offset,
2134 refs_to_add, extent_op);
2135 if ((ret < 0 && ret != -EAGAIN) || !ret)
2136 goto out;
2137
2138 /*
2139 * Ok we had -EAGAIN which means we didn't have space to insert and
2140 * inline extent ref, so just update the reference count and add a
2141 * normal backref.
2142 */
2143 leaf = path->nodes[0];
2144 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2145 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2146 refs = btrfs_extent_refs(leaf, item);
2147 btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2148 if (extent_op)
2149 __run_delayed_extent_op(extent_op, leaf, item);
2150
2151 btrfs_mark_buffer_dirty(leaf);
2152 btrfs_release_path(path);
2153
2154 path->reada = READA_FORWARD;
2155 path->leave_spinning = 1;
2156 /* now insert the actual backref */
2157 ret = insert_extent_backref(trans, root->fs_info->extent_root,
2158 path, bytenr, parent, root_objectid,
2159 owner, offset, refs_to_add);
2160 if (ret)
2161 btrfs_abort_transaction(trans, ret);
2162 out:
2163 btrfs_free_path(path);
2164 return ret;
2165 }
2166
2167 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2168 struct btrfs_root *root,
2169 struct btrfs_delayed_ref_node *node,
2170 struct btrfs_delayed_extent_op *extent_op,
2171 int insert_reserved)
2172 {
2173 int ret = 0;
2174 struct btrfs_delayed_data_ref *ref;
2175 struct btrfs_key ins;
2176 u64 parent = 0;
2177 u64 ref_root = 0;
2178 u64 flags = 0;
2179
2180 ins.objectid = node->bytenr;
2181 ins.offset = node->num_bytes;
2182 ins.type = BTRFS_EXTENT_ITEM_KEY;
2183
2184 ref = btrfs_delayed_node_to_data_ref(node);
2185 trace_run_delayed_data_ref(root->fs_info, node, ref, node->action);
2186
2187 if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2188 parent = ref->parent;
2189 ref_root = ref->root;
2190
2191 if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2192 if (extent_op)
2193 flags |= extent_op->flags_to_set;
2194 ret = alloc_reserved_file_extent(trans, root,
2195 parent, ref_root, flags,
2196 ref->objectid, ref->offset,
2197 &ins, node->ref_mod);
2198 } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2199 ret = __btrfs_inc_extent_ref(trans, root, node, parent,
2200 ref_root, ref->objectid,
2201 ref->offset, node->ref_mod,
2202 extent_op);
2203 } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2204 ret = __btrfs_free_extent(trans, root, node, parent,
2205 ref_root, ref->objectid,
2206 ref->offset, node->ref_mod,
2207 extent_op);
2208 } else {
2209 BUG();
2210 }
2211 return ret;
2212 }
2213
2214 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2215 struct extent_buffer *leaf,
2216 struct btrfs_extent_item *ei)
2217 {
2218 u64 flags = btrfs_extent_flags(leaf, ei);
2219 if (extent_op->update_flags) {
2220 flags |= extent_op->flags_to_set;
2221 btrfs_set_extent_flags(leaf, ei, flags);
2222 }
2223
2224 if (extent_op->update_key) {
2225 struct btrfs_tree_block_info *bi;
2226 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2227 bi = (struct btrfs_tree_block_info *)(ei + 1);
2228 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2229 }
2230 }
2231
2232 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2233 struct btrfs_root *root,
2234 struct btrfs_delayed_ref_node *node,
2235 struct btrfs_delayed_extent_op *extent_op)
2236 {
2237 struct btrfs_key key;
2238 struct btrfs_path *path;
2239 struct btrfs_extent_item *ei;
2240 struct extent_buffer *leaf;
2241 u32 item_size;
2242 int ret;
2243 int err = 0;
2244 int metadata = !extent_op->is_data;
2245
2246 if (trans->aborted)
2247 return 0;
2248
2249 if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2250 metadata = 0;
2251
2252 path = btrfs_alloc_path();
2253 if (!path)
2254 return -ENOMEM;
2255
2256 key.objectid = node->bytenr;
2257
2258 if (metadata) {
2259 key.type = BTRFS_METADATA_ITEM_KEY;
2260 key.offset = extent_op->level;
2261 } else {
2262 key.type = BTRFS_EXTENT_ITEM_KEY;
2263 key.offset = node->num_bytes;
2264 }
2265
2266 again:
2267 path->reada = READA_FORWARD;
2268 path->leave_spinning = 1;
2269 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2270 path, 0, 1);
2271 if (ret < 0) {
2272 err = ret;
2273 goto out;
2274 }
2275 if (ret > 0) {
2276 if (metadata) {
2277 if (path->slots[0] > 0) {
2278 path->slots[0]--;
2279 btrfs_item_key_to_cpu(path->nodes[0], &key,
2280 path->slots[0]);
2281 if (key.objectid == node->bytenr &&
2282 key.type == BTRFS_EXTENT_ITEM_KEY &&
2283 key.offset == node->num_bytes)
2284 ret = 0;
2285 }
2286 if (ret > 0) {
2287 btrfs_release_path(path);
2288 metadata = 0;
2289
2290 key.objectid = node->bytenr;
2291 key.offset = node->num_bytes;
2292 key.type = BTRFS_EXTENT_ITEM_KEY;
2293 goto again;
2294 }
2295 } else {
2296 err = -EIO;
2297 goto out;
2298 }
2299 }
2300
2301 leaf = path->nodes[0];
2302 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2303 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2304 if (item_size < sizeof(*ei)) {
2305 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2306 path, (u64)-1, 0);
2307 if (ret < 0) {
2308 err = ret;
2309 goto out;
2310 }
2311 leaf = path->nodes[0];
2312 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2313 }
2314 #endif
2315 BUG_ON(item_size < sizeof(*ei));
2316 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2317 __run_delayed_extent_op(extent_op, leaf, ei);
2318
2319 btrfs_mark_buffer_dirty(leaf);
2320 out:
2321 btrfs_free_path(path);
2322 return err;
2323 }
2324
2325 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2326 struct btrfs_root *root,
2327 struct btrfs_delayed_ref_node *node,
2328 struct btrfs_delayed_extent_op *extent_op,
2329 int insert_reserved)
2330 {
2331 int ret = 0;
2332 struct btrfs_delayed_tree_ref *ref;
2333 struct btrfs_key ins;
2334 u64 parent = 0;
2335 u64 ref_root = 0;
2336 bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
2337 SKINNY_METADATA);
2338
2339 ref = btrfs_delayed_node_to_tree_ref(node);
2340 trace_run_delayed_tree_ref(root->fs_info, node, ref, node->action);
2341
2342 if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2343 parent = ref->parent;
2344 ref_root = ref->root;
2345
2346 ins.objectid = node->bytenr;
2347 if (skinny_metadata) {
2348 ins.offset = ref->level;
2349 ins.type = BTRFS_METADATA_ITEM_KEY;
2350 } else {
2351 ins.offset = node->num_bytes;
2352 ins.type = BTRFS_EXTENT_ITEM_KEY;
2353 }
2354
2355 if (node->ref_mod != 1) {
2356 btrfs_err(root->fs_info,
2357 "btree block(%llu) has %d references rather than 1: action %d ref_root %llu parent %llu",
2358 node->bytenr, node->ref_mod, node->action, ref_root,
2359 parent);
2360 return -EIO;
2361 }
2362 if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2363 BUG_ON(!extent_op || !extent_op->update_flags);
2364 ret = alloc_reserved_tree_block(trans, root,
2365 parent, ref_root,
2366 extent_op->flags_to_set,
2367 &extent_op->key,
2368 ref->level, &ins);
2369 } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2370 ret = __btrfs_inc_extent_ref(trans, root, node,
2371 parent, ref_root,
2372 ref->level, 0, 1,
2373 extent_op);
2374 } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2375 ret = __btrfs_free_extent(trans, root, node,
2376 parent, ref_root,
2377 ref->level, 0, 1, extent_op);
2378 } else {
2379 BUG();
2380 }
2381 return ret;
2382 }
2383
2384 /* helper function to actually process a single delayed ref entry */
2385 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2386 struct btrfs_root *root,
2387 struct btrfs_delayed_ref_node *node,
2388 struct btrfs_delayed_extent_op *extent_op,
2389 int insert_reserved)
2390 {
2391 int ret = 0;
2392
2393 if (trans->aborted) {
2394 if (insert_reserved)
2395 btrfs_pin_extent(root, node->bytenr,
2396 node->num_bytes, 1);
2397 return 0;
2398 }
2399
2400 if (btrfs_delayed_ref_is_head(node)) {
2401 struct btrfs_delayed_ref_head *head;
2402 /*
2403 * we've hit the end of the chain and we were supposed
2404 * to insert this extent into the tree. But, it got
2405 * deleted before we ever needed to insert it, so all
2406 * we have to do is clean up the accounting
2407 */
2408 BUG_ON(extent_op);
2409 head = btrfs_delayed_node_to_head(node);
2410 trace_run_delayed_ref_head(root->fs_info, node, head,
2411 node->action);
2412
2413 if (insert_reserved) {
2414 btrfs_pin_extent(root, node->bytenr,
2415 node->num_bytes, 1);
2416 if (head->is_data) {
2417 ret = btrfs_del_csums(trans, root,
2418 node->bytenr,
2419 node->num_bytes);
2420 }
2421 }
2422
2423 /* Also free its reserved qgroup space */
2424 btrfs_qgroup_free_delayed_ref(root->fs_info,
2425 head->qgroup_ref_root,
2426 head->qgroup_reserved);
2427 return ret;
2428 }
2429
2430 if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2431 node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2432 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2433 insert_reserved);
2434 else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2435 node->type == BTRFS_SHARED_DATA_REF_KEY)
2436 ret = run_delayed_data_ref(trans, root, node, extent_op,
2437 insert_reserved);
2438 else
2439 BUG();
2440 return ret;
2441 }
2442
2443 static inline struct btrfs_delayed_ref_node *
2444 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2445 {
2446 struct btrfs_delayed_ref_node *ref;
2447
2448 if (list_empty(&head->ref_list))
2449 return NULL;
2450
2451 /*
2452 * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
2453 * This is to prevent a ref count from going down to zero, which deletes
2454 * the extent item from the extent tree, when there still are references
2455 * to add, which would fail because they would not find the extent item.
2456 */
2457 list_for_each_entry(ref, &head->ref_list, list) {
2458 if (ref->action == BTRFS_ADD_DELAYED_REF)
2459 return ref;
2460 }
2461
2462 return list_entry(head->ref_list.next, struct btrfs_delayed_ref_node,
2463 list);
2464 }
2465
2466 /*
2467 * Returns 0 on success or if called with an already aborted transaction.
2468 * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2469 */
2470 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2471 struct btrfs_root *root,
2472 unsigned long nr)
2473 {
2474 struct btrfs_delayed_ref_root *delayed_refs;
2475 struct btrfs_delayed_ref_node *ref;
2476 struct btrfs_delayed_ref_head *locked_ref = NULL;
2477 struct btrfs_delayed_extent_op *extent_op;
2478 struct btrfs_fs_info *fs_info = root->fs_info;
2479 ktime_t start = ktime_get();
2480 int ret;
2481 unsigned long count = 0;
2482 unsigned long actual_count = 0;
2483 int must_insert_reserved = 0;
2484
2485 delayed_refs = &trans->transaction->delayed_refs;
2486 while (1) {
2487 if (!locked_ref) {
2488 if (count >= nr)
2489 break;
2490
2491 spin_lock(&delayed_refs->lock);
2492 locked_ref = btrfs_select_ref_head(trans);
2493 if (!locked_ref) {
2494 spin_unlock(&delayed_refs->lock);
2495 break;
2496 }
2497
2498 /* grab the lock that says we are going to process
2499 * all the refs for this head */
2500 ret = btrfs_delayed_ref_lock(trans, locked_ref);
2501 spin_unlock(&delayed_refs->lock);
2502 /*
2503 * we may have dropped the spin lock to get the head
2504 * mutex lock, and that might have given someone else
2505 * time to free the head. If that's true, it has been
2506 * removed from our list and we can move on.
2507 */
2508 if (ret == -EAGAIN) {
2509 locked_ref = NULL;
2510 count++;
2511 continue;
2512 }
2513 }
2514
2515 /*
2516 * We need to try and merge add/drops of the same ref since we
2517 * can run into issues with relocate dropping the implicit ref
2518 * and then it being added back again before the drop can
2519 * finish. If we merged anything we need to re-loop so we can
2520 * get a good ref.
2521 * Or we can get node references of the same type that weren't
2522 * merged when created due to bumps in the tree mod seq, and
2523 * we need to merge them to prevent adding an inline extent
2524 * backref before dropping it (triggering a BUG_ON at
2525 * insert_inline_extent_backref()).
2526 */
2527 spin_lock(&locked_ref->lock);
2528 btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
2529 locked_ref);
2530
2531 /*
2532 * locked_ref is the head node, so we have to go one
2533 * node back for any delayed ref updates
2534 */
2535 ref = select_delayed_ref(locked_ref);
2536
2537 if (ref && ref->seq &&
2538 btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2539 spin_unlock(&locked_ref->lock);
2540 btrfs_delayed_ref_unlock(locked_ref);
2541 spin_lock(&delayed_refs->lock);
2542 locked_ref->processing = 0;
2543 delayed_refs->num_heads_ready++;
2544 spin_unlock(&delayed_refs->lock);
2545 locked_ref = NULL;
2546 cond_resched();
2547 count++;
2548 continue;
2549 }
2550
2551 /*
2552 * record the must insert reserved flag before we
2553 * drop the spin lock.
2554 */
2555 must_insert_reserved = locked_ref->must_insert_reserved;
2556 locked_ref->must_insert_reserved = 0;
2557
2558 extent_op = locked_ref->extent_op;
2559 locked_ref->extent_op = NULL;
2560
2561 if (!ref) {
2562
2563
2564 /* All delayed refs have been processed, Go ahead
2565 * and send the head node to run_one_delayed_ref,
2566 * so that any accounting fixes can happen
2567 */
2568 ref = &locked_ref->node;
2569
2570 if (extent_op && must_insert_reserved) {
2571 btrfs_free_delayed_extent_op(extent_op);
2572 extent_op = NULL;
2573 }
2574
2575 if (extent_op) {
2576 spin_unlock(&locked_ref->lock);
2577 ret = run_delayed_extent_op(trans, root,
2578 ref, extent_op);
2579 btrfs_free_delayed_extent_op(extent_op);
2580
2581 if (ret) {
2582 /*
2583 * Need to reset must_insert_reserved if
2584 * there was an error so the abort stuff
2585 * can cleanup the reserved space
2586 * properly.
2587 */
2588 if (must_insert_reserved)
2589 locked_ref->must_insert_reserved = 1;
2590 locked_ref->processing = 0;
2591 btrfs_debug(fs_info,
2592 "run_delayed_extent_op returned %d",
2593 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",
2654 ret);
2655 return ret;
2656 }
2657
2658 /*
2659 * If this node is a head, that means all the refs in this head
2660 * have been dealt with, and we will pick the next head to deal
2661 * with, so we must unlock the head and drop it from the cluster
2662 * list before we release it.
2663 */
2664 if (btrfs_delayed_ref_is_head(ref)) {
2665 if (locked_ref->is_data &&
2666 locked_ref->total_ref_mod < 0) {
2667 spin_lock(&delayed_refs->lock);
2668 delayed_refs->pending_csums -= ref->num_bytes;
2669 spin_unlock(&delayed_refs->lock);
2670 }
2671 btrfs_delayed_ref_unlock(locked_ref);
2672 locked_ref = NULL;
2673 }
2674 btrfs_put_delayed_ref(ref);
2675 count++;
2676 cond_resched();
2677 }
2678
2679 /*
2680 * We don't want to include ref heads since we can have empty ref heads
2681 * and those will drastically skew our runtime down since we just do
2682 * accounting, no actual extent tree updates.
2683 */
2684 if (actual_count > 0) {
2685 u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2686 u64 avg;
2687
2688 /*
2689 * We weigh the current average higher than our current runtime
2690 * to avoid large swings in the average.
2691 */
2692 spin_lock(&delayed_refs->lock);
2693 avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2694 fs_info->avg_delayed_ref_runtime = avg >> 2; /* div by 4 */
2695 spin_unlock(&delayed_refs->lock);
2696 }
2697 return 0;
2698 }
2699
2700 #ifdef SCRAMBLE_DELAYED_REFS
2701 /*
2702 * Normally delayed refs get processed in ascending bytenr order. This
2703 * correlates in most cases to the order added. To expose dependencies on this
2704 * order, we start to process the tree in the middle instead of the beginning
2705 */
2706 static u64 find_middle(struct rb_root *root)
2707 {
2708 struct rb_node *n = root->rb_node;
2709 struct btrfs_delayed_ref_node *entry;
2710 int alt = 1;
2711 u64 middle;
2712 u64 first = 0, last = 0;
2713
2714 n = rb_first(root);
2715 if (n) {
2716 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2717 first = entry->bytenr;
2718 }
2719 n = rb_last(root);
2720 if (n) {
2721 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2722 last = entry->bytenr;
2723 }
2724 n = root->rb_node;
2725
2726 while (n) {
2727 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2728 WARN_ON(!entry->in_tree);
2729
2730 middle = entry->bytenr;
2731
2732 if (alt)
2733 n = n->rb_left;
2734 else
2735 n = n->rb_right;
2736
2737 alt = 1 - alt;
2738 }
2739 return middle;
2740 }
2741 #endif
2742
2743 static inline u64 heads_to_leaves(struct btrfs_root *root, u64 heads)
2744 {
2745 u64 num_bytes;
2746
2747 num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2748 sizeof(struct btrfs_extent_inline_ref));
2749 if (!btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2750 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2751
2752 /*
2753 * We don't ever fill up leaves all the way so multiply by 2 just to be
2754 * closer to what we're really going to want to use.
2755 */
2756 return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(root));
2757 }
2758
2759 /*
2760 * Takes the number of bytes to be csumm'ed and figures out how many leaves it
2761 * would require to store the csums for that many bytes.
2762 */
2763 u64 btrfs_csum_bytes_to_leaves(struct btrfs_root *root, u64 csum_bytes)
2764 {
2765 u64 csum_size;
2766 u64 num_csums_per_leaf;
2767 u64 num_csums;
2768
2769 csum_size = BTRFS_MAX_ITEM_SIZE(root);
2770 num_csums_per_leaf = div64_u64(csum_size,
2771 (u64)btrfs_super_csum_size(root->fs_info->super_copy));
2772 num_csums = div64_u64(csum_bytes, root->sectorsize);
2773 num_csums += num_csums_per_leaf - 1;
2774 num_csums = div64_u64(num_csums, num_csums_per_leaf);
2775 return num_csums;
2776 }
2777
2778 int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans,
2779 struct btrfs_root *root)
2780 {
2781 struct btrfs_block_rsv *global_rsv;
2782 u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2783 u64 csum_bytes = trans->transaction->delayed_refs.pending_csums;
2784 u64 num_dirty_bgs = trans->transaction->num_dirty_bgs;
2785 u64 num_bytes, num_dirty_bgs_bytes;
2786 int ret = 0;
2787
2788 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
2789 num_heads = heads_to_leaves(root, num_heads);
2790 if (num_heads > 1)
2791 num_bytes += (num_heads - 1) * root->nodesize;
2792 num_bytes <<= 1;
2793 num_bytes += btrfs_csum_bytes_to_leaves(root, csum_bytes) * root->nodesize;
2794 num_dirty_bgs_bytes = btrfs_calc_trans_metadata_size(root,
2795 num_dirty_bgs);
2796 global_rsv = &root->fs_info->global_block_rsv;
2797
2798 /*
2799 * If we can't allocate any more chunks lets make sure we have _lots_ of
2800 * wiggle room since running delayed refs can create more delayed refs.
2801 */
2802 if (global_rsv->space_info->full) {
2803 num_dirty_bgs_bytes <<= 1;
2804 num_bytes <<= 1;
2805 }
2806
2807 spin_lock(&global_rsv->lock);
2808 if (global_rsv->reserved <= num_bytes + num_dirty_bgs_bytes)
2809 ret = 1;
2810 spin_unlock(&global_rsv->lock);
2811 return ret;
2812 }
2813
2814 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2815 struct btrfs_root *root)
2816 {
2817 struct btrfs_fs_info *fs_info = root->fs_info;
2818 u64 num_entries =
2819 atomic_read(&trans->transaction->delayed_refs.num_entries);
2820 u64 avg_runtime;
2821 u64 val;
2822
2823 smp_mb();
2824 avg_runtime = fs_info->avg_delayed_ref_runtime;
2825 val = num_entries * avg_runtime;
2826 if (num_entries * avg_runtime >= NSEC_PER_SEC)
2827 return 1;
2828 if (val >= NSEC_PER_SEC / 2)
2829 return 2;
2830
2831 return btrfs_check_space_for_delayed_refs(trans, root);
2832 }
2833
2834 struct async_delayed_refs {
2835 struct btrfs_root *root;
2836 u64 transid;
2837 int count;
2838 int error;
2839 int sync;
2840 struct completion wait;
2841 struct btrfs_work work;
2842 };
2843
2844 static void delayed_ref_async_start(struct btrfs_work *work)
2845 {
2846 struct async_delayed_refs *async;
2847 struct btrfs_trans_handle *trans;
2848 int ret;
2849
2850 async = container_of(work, struct async_delayed_refs, work);
2851
2852 /* if the commit is already started, we don't need to wait here */
2853 if (btrfs_transaction_blocked(async->root->fs_info))
2854 goto done;
2855
2856 trans = btrfs_join_transaction(async->root);
2857 if (IS_ERR(trans)) {
2858 async->error = PTR_ERR(trans);
2859 goto done;
2860 }
2861
2862 /*
2863 * trans->sync means that when we call end_transaction, we won't
2864 * wait on delayed refs
2865 */
2866 trans->sync = true;
2867
2868 /* Don't bother flushing if we got into a different transaction */
2869 if (trans->transid > async->transid)
2870 goto end;
2871
2872 ret = btrfs_run_delayed_refs(trans, async->root, async->count);
2873 if (ret)
2874 async->error = ret;
2875 end:
2876 ret = btrfs_end_transaction(trans, async->root);
2877 if (ret && !async->error)
2878 async->error = ret;
2879 done:
2880 if (async->sync)
2881 complete(&async->wait);
2882 else
2883 kfree(async);
2884 }
2885
2886 int btrfs_async_run_delayed_refs(struct btrfs_root *root,
2887 unsigned long count, u64 transid, int wait)
2888 {
2889 struct async_delayed_refs *async;
2890 int ret;
2891
2892 async = kmalloc(sizeof(*async), GFP_NOFS);
2893 if (!async)
2894 return -ENOMEM;
2895
2896 async->root = root->fs_info->tree_root;
2897 async->count = count;
2898 async->error = 0;
2899 async->transid = transid;
2900 if (wait)
2901 async->sync = 1;
2902 else
2903 async->sync = 0;
2904 init_completion(&async->wait);
2905
2906 btrfs_init_work(&async->work, btrfs_extent_refs_helper,
2907 delayed_ref_async_start, NULL, NULL);
2908
2909 btrfs_queue_work(root->fs_info->extent_workers, &async->work);
2910
2911 if (wait) {
2912 wait_for_completion(&async->wait);
2913 ret = async->error;
2914 kfree(async);
2915 return ret;
2916 }
2917 return 0;
2918 }
2919
2920 /*
2921 * this starts processing the delayed reference count updates and
2922 * extent insertions we have queued up so far. count can be
2923 * 0, which means to process everything in the tree at the start
2924 * of the run (but not newly added entries), or it can be some target
2925 * number you'd like to process.
2926 *
2927 * Returns 0 on success or if called with an aborted transaction
2928 * Returns <0 on error and aborts the transaction
2929 */
2930 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2931 struct btrfs_root *root, unsigned long count)
2932 {
2933 struct rb_node *node;
2934 struct btrfs_delayed_ref_root *delayed_refs;
2935 struct btrfs_delayed_ref_head *head;
2936 int ret;
2937 int run_all = count == (unsigned long)-1;
2938 bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
2939
2940 /* We'll clean this up in btrfs_cleanup_transaction */
2941 if (trans->aborted)
2942 return 0;
2943
2944 if (test_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &root->fs_info->flags))
2945 return 0;
2946
2947 if (root == root->fs_info->extent_root)
2948 root = root->fs_info->tree_root;
2949
2950 delayed_refs = &trans->transaction->delayed_refs;
2951 if (count == 0)
2952 count = atomic_read(&delayed_refs->num_entries) * 2;
2953
2954 again:
2955 #ifdef SCRAMBLE_DELAYED_REFS
2956 delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2957 #endif
2958 trans->can_flush_pending_bgs = false;
2959 ret = __btrfs_run_delayed_refs(trans, root, count);
2960 if (ret < 0) {
2961 btrfs_abort_transaction(trans, ret);
2962 return ret;
2963 }
2964
2965 if (run_all) {
2966 if (!list_empty(&trans->new_bgs))
2967 btrfs_create_pending_block_groups(trans, root);
2968
2969 spin_lock(&delayed_refs->lock);
2970 node = rb_first(&delayed_refs->href_root);
2971 if (!node) {
2972 spin_unlock(&delayed_refs->lock);
2973 goto out;
2974 }
2975
2976 while (node) {
2977 head = rb_entry(node, struct btrfs_delayed_ref_head,
2978 href_node);
2979 if (btrfs_delayed_ref_is_head(&head->node)) {
2980 struct btrfs_delayed_ref_node *ref;
2981
2982 ref = &head->node;
2983 atomic_inc(&ref->refs);
2984
2985 spin_unlock(&delayed_refs->lock);
2986 /*
2987 * Mutex was contended, block until it's
2988 * released and try again
2989 */
2990 mutex_lock(&head->mutex);
2991 mutex_unlock(&head->mutex);
2992
2993 btrfs_put_delayed_ref(ref);
2994 cond_resched();
2995 goto again;
2996 } else {
2997 WARN_ON(1);
2998 }
2999 node = rb_next(node);
3000 }
3001 spin_unlock(&delayed_refs->lock);
3002 cond_resched();
3003 goto again;
3004 }
3005 out:
3006 assert_qgroups_uptodate(trans);
3007 trans->can_flush_pending_bgs = can_flush_pending_bgs;
3008 return 0;
3009 }
3010
3011 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
3012 struct btrfs_root *root,
3013 u64 bytenr, u64 num_bytes, u64 flags,
3014 int level, int is_data)
3015 {
3016 struct btrfs_delayed_extent_op *extent_op;
3017 int ret;
3018
3019 extent_op = btrfs_alloc_delayed_extent_op();
3020 if (!extent_op)
3021 return -ENOMEM;
3022
3023 extent_op->flags_to_set = flags;
3024 extent_op->update_flags = true;
3025 extent_op->update_key = false;
3026 extent_op->is_data = is_data ? true : false;
3027 extent_op->level = level;
3028
3029 ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
3030 num_bytes, extent_op);
3031 if (ret)
3032 btrfs_free_delayed_extent_op(extent_op);
3033 return ret;
3034 }
3035
3036 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
3037 struct btrfs_root *root,
3038 struct btrfs_path *path,
3039 u64 objectid, u64 offset, u64 bytenr)
3040 {
3041 struct btrfs_delayed_ref_head *head;
3042 struct btrfs_delayed_ref_node *ref;
3043 struct btrfs_delayed_data_ref *data_ref;
3044 struct btrfs_delayed_ref_root *delayed_refs;
3045 int ret = 0;
3046
3047 delayed_refs = &trans->transaction->delayed_refs;
3048 spin_lock(&delayed_refs->lock);
3049 head = btrfs_find_delayed_ref_head(trans, bytenr);
3050 if (!head) {
3051 spin_unlock(&delayed_refs->lock);
3052 return 0;
3053 }
3054
3055 if (!mutex_trylock(&head->mutex)) {
3056 atomic_inc(&head->node.refs);
3057 spin_unlock(&delayed_refs->lock);
3058
3059 btrfs_release_path(path);
3060
3061 /*
3062 * Mutex was contended, block until it's released and let
3063 * caller try again
3064 */
3065 mutex_lock(&head->mutex);
3066 mutex_unlock(&head->mutex);
3067 btrfs_put_delayed_ref(&head->node);
3068 return -EAGAIN;
3069 }
3070 spin_unlock(&delayed_refs->lock);
3071
3072 spin_lock(&head->lock);
3073 list_for_each_entry(ref, &head->ref_list, list) {
3074 /* If it's a shared ref we know a cross reference exists */
3075 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
3076 ret = 1;
3077 break;
3078 }
3079
3080 data_ref = btrfs_delayed_node_to_data_ref(ref);
3081
3082 /*
3083 * If our ref doesn't match the one we're currently looking at
3084 * then we have a cross reference.
3085 */
3086 if (data_ref->root != root->root_key.objectid ||
3087 data_ref->objectid != objectid ||
3088 data_ref->offset != offset) {
3089 ret = 1;
3090 break;
3091 }
3092 }
3093 spin_unlock(&head->lock);
3094 mutex_unlock(&head->mutex);
3095 return ret;
3096 }
3097
3098 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
3099 struct btrfs_root *root,
3100 struct btrfs_path *path,
3101 u64 objectid, u64 offset, u64 bytenr)
3102 {
3103 struct btrfs_root *extent_root = root->fs_info->extent_root;
3104 struct extent_buffer *leaf;
3105 struct btrfs_extent_data_ref *ref;
3106 struct btrfs_extent_inline_ref *iref;
3107 struct btrfs_extent_item *ei;
3108 struct btrfs_key key;
3109 u32 item_size;
3110 int ret;
3111
3112 key.objectid = bytenr;
3113 key.offset = (u64)-1;
3114 key.type = BTRFS_EXTENT_ITEM_KEY;
3115
3116 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
3117 if (ret < 0)
3118 goto out;
3119 BUG_ON(ret == 0); /* Corruption */
3120
3121 ret = -ENOENT;
3122 if (path->slots[0] == 0)
3123 goto out;
3124
3125 path->slots[0]--;
3126 leaf = path->nodes[0];
3127 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3128
3129 if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
3130 goto out;
3131
3132 ret = 1;
3133 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
3134 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3135 if (item_size < sizeof(*ei)) {
3136 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3137 goto out;
3138 }
3139 #endif
3140 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
3141
3142 if (item_size != sizeof(*ei) +
3143 btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
3144 goto out;
3145
3146 if (btrfs_extent_generation(leaf, ei) <=
3147 btrfs_root_last_snapshot(&root->root_item))
3148 goto out;
3149
3150 iref = (struct btrfs_extent_inline_ref *)(ei + 1);
3151 if (btrfs_extent_inline_ref_type(leaf, iref) !=
3152 BTRFS_EXTENT_DATA_REF_KEY)
3153 goto out;
3154
3155 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
3156 if (btrfs_extent_refs(leaf, ei) !=
3157 btrfs_extent_data_ref_count(leaf, ref) ||
3158 btrfs_extent_data_ref_root(leaf, ref) !=
3159 root->root_key.objectid ||
3160 btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
3161 btrfs_extent_data_ref_offset(leaf, ref) != offset)
3162 goto out;
3163
3164 ret = 0;
3165 out:
3166 return ret;
3167 }
3168
3169 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
3170 struct btrfs_root *root,
3171 u64 objectid, u64 offset, u64 bytenr)
3172 {
3173 struct btrfs_path *path;
3174 int ret;
3175 int ret2;
3176
3177 path = btrfs_alloc_path();
3178 if (!path)
3179 return -ENOENT;
3180
3181 do {
3182 ret = check_committed_ref(trans, root, path, objectid,
3183 offset, bytenr);
3184 if (ret && ret != -ENOENT)
3185 goto out;
3186
3187 ret2 = check_delayed_ref(trans, root, path, objectid,
3188 offset, bytenr);
3189 } while (ret2 == -EAGAIN);
3190
3191 if (ret2 && ret2 != -ENOENT) {
3192 ret = ret2;
3193 goto out;
3194 }
3195
3196 if (ret != -ENOENT || ret2 != -ENOENT)
3197 ret = 0;
3198 out:
3199 btrfs_free_path(path);
3200 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3201 WARN_ON(ret > 0);
3202 return ret;
3203 }
3204
3205 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3206 struct btrfs_root *root,
3207 struct extent_buffer *buf,
3208 int full_backref, int inc)
3209 {
3210 u64 bytenr;
3211 u64 num_bytes;
3212 u64 parent;
3213 u64 ref_root;
3214 u32 nritems;
3215 struct btrfs_key key;
3216 struct btrfs_file_extent_item *fi;
3217 int i;
3218 int level;
3219 int ret = 0;
3220 int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
3221 u64, u64, u64, u64, u64, u64);
3222
3223
3224 if (btrfs_is_testing(root->fs_info))
3225 return 0;
3226
3227 ref_root = btrfs_header_owner(buf);
3228 nritems = btrfs_header_nritems(buf);
3229 level = btrfs_header_level(buf);
3230
3231 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
3232 return 0;
3233
3234 if (inc)
3235 process_func = btrfs_inc_extent_ref;
3236 else
3237 process_func = btrfs_free_extent;
3238
3239 if (full_backref)
3240 parent = buf->start;
3241 else
3242 parent = 0;
3243
3244 for (i = 0; i < nritems; i++) {
3245 if (level == 0) {
3246 btrfs_item_key_to_cpu(buf, &key, i);
3247 if (key.type != BTRFS_EXTENT_DATA_KEY)
3248 continue;
3249 fi = btrfs_item_ptr(buf, i,
3250 struct btrfs_file_extent_item);
3251 if (btrfs_file_extent_type(buf, fi) ==
3252 BTRFS_FILE_EXTENT_INLINE)
3253 continue;
3254 bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3255 if (bytenr == 0)
3256 continue;
3257
3258 num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3259 key.offset -= btrfs_file_extent_offset(buf, fi);
3260 ret = process_func(trans, root, bytenr, num_bytes,
3261 parent, ref_root, key.objectid,
3262 key.offset);
3263 if (ret)
3264 goto fail;
3265 } else {
3266 bytenr = btrfs_node_blockptr(buf, i);
3267 num_bytes = root->nodesize;
3268 ret = process_func(trans, root, bytenr, num_bytes,
3269 parent, ref_root, level - 1, 0);
3270 if (ret)
3271 goto fail;
3272 }
3273 }
3274 return 0;
3275 fail:
3276 return ret;
3277 }
3278
3279 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3280 struct extent_buffer *buf, int full_backref)
3281 {
3282 return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
3283 }
3284
3285 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3286 struct extent_buffer *buf, int full_backref)
3287 {
3288 return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
3289 }
3290
3291 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3292 struct btrfs_root *root,
3293 struct btrfs_path *path,
3294 struct btrfs_block_group_cache *cache)
3295 {
3296 int ret;
3297 struct btrfs_root *extent_root = root->fs_info->extent_root;
3298 unsigned long bi;
3299 struct extent_buffer *leaf;
3300
3301 ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3302 if (ret) {
3303 if (ret > 0)
3304 ret = -ENOENT;
3305 goto fail;
3306 }
3307
3308 leaf = path->nodes[0];
3309 bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3310 write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3311 btrfs_mark_buffer_dirty(leaf);
3312 fail:
3313 btrfs_release_path(path);
3314 return ret;
3315
3316 }
3317
3318 static struct btrfs_block_group_cache *
3319 next_block_group(struct btrfs_root *root,
3320 struct btrfs_block_group_cache *cache)
3321 {
3322 struct rb_node *node;
3323
3324 spin_lock(&root->fs_info->block_group_cache_lock);
3325
3326 /* If our block group was removed, we need a full search. */
3327 if (RB_EMPTY_NODE(&cache->cache_node)) {
3328 const u64 next_bytenr = cache->key.objectid + cache->key.offset;
3329
3330 spin_unlock(&root->fs_info->block_group_cache_lock);
3331 btrfs_put_block_group(cache);
3332 cache = btrfs_lookup_first_block_group(root->fs_info,
3333 next_bytenr);
3334 return cache;
3335 }
3336 node = rb_next(&cache->cache_node);
3337 btrfs_put_block_group(cache);
3338 if (node) {
3339 cache = rb_entry(node, struct btrfs_block_group_cache,
3340 cache_node);
3341 btrfs_get_block_group(cache);
3342 } else
3343 cache = NULL;
3344 spin_unlock(&root->fs_info->block_group_cache_lock);
3345 return cache;
3346 }
3347
3348 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3349 struct btrfs_trans_handle *trans,
3350 struct btrfs_path *path)
3351 {
3352 struct btrfs_root *root = block_group->fs_info->tree_root;
3353 struct inode *inode = NULL;
3354 u64 alloc_hint = 0;
3355 int dcs = BTRFS_DC_ERROR;
3356 u64 num_pages = 0;
3357 int retries = 0;
3358 int ret = 0;
3359
3360 /*
3361 * If this block group is smaller than 100 megs don't bother caching the
3362 * block group.
3363 */
3364 if (block_group->key.offset < (100 * SZ_1M)) {
3365 spin_lock(&block_group->lock);
3366 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3367 spin_unlock(&block_group->lock);
3368 return 0;
3369 }
3370
3371 if (trans->aborted)
3372 return 0;
3373 again:
3374 inode = lookup_free_space_inode(root, block_group, path);
3375 if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3376 ret = PTR_ERR(inode);
3377 btrfs_release_path(path);
3378 goto out;
3379 }
3380
3381 if (IS_ERR(inode)) {
3382 BUG_ON(retries);
3383 retries++;
3384
3385 if (block_group->ro)
3386 goto out_free;
3387
3388 ret = create_free_space_inode(root, trans, block_group, path);
3389 if (ret)
3390 goto out_free;
3391 goto again;
3392 }
3393
3394 /* We've already setup this transaction, go ahead and exit */
3395 if (block_group->cache_generation == trans->transid &&
3396 i_size_read(inode)) {
3397 dcs = BTRFS_DC_SETUP;
3398 goto out_put;
3399 }
3400
3401 /*
3402 * We want to set the generation to 0, that way if anything goes wrong
3403 * from here on out we know not to trust this cache when we load up next
3404 * time.
3405 */
3406 BTRFS_I(inode)->generation = 0;
3407 ret = btrfs_update_inode(trans, root, inode);
3408 if (ret) {
3409 /*
3410 * So theoretically we could recover from this, simply set the
3411 * super cache generation to 0 so we know to invalidate the
3412 * cache, but then we'd have to keep track of the block groups
3413 * that fail this way so we know we _have_ to reset this cache
3414 * before the next commit or risk reading stale cache. So to
3415 * limit our exposure to horrible edge cases lets just abort the
3416 * transaction, this only happens in really bad situations
3417 * anyway.
3418 */
3419 btrfs_abort_transaction(trans, ret);
3420 goto out_put;
3421 }
3422 WARN_ON(ret);
3423
3424 if (i_size_read(inode) > 0) {
3425 ret = btrfs_check_trunc_cache_free_space(root,
3426 &root->fs_info->global_block_rsv);
3427 if (ret)
3428 goto out_put;
3429
3430 ret = btrfs_truncate_free_space_cache(root, trans, NULL, inode);
3431 if (ret)
3432 goto out_put;
3433 }
3434
3435 spin_lock(&block_group->lock);
3436 if (block_group->cached != BTRFS_CACHE_FINISHED ||
3437 !btrfs_test_opt(root->fs_info, SPACE_CACHE)) {
3438 /*
3439 * don't bother trying to write stuff out _if_
3440 * a) we're not cached,
3441 * b) we're with nospace_cache mount option.
3442 */
3443 dcs = BTRFS_DC_WRITTEN;
3444 spin_unlock(&block_group->lock);
3445 goto out_put;
3446 }
3447 spin_unlock(&block_group->lock);
3448
3449 /*
3450 * We hit an ENOSPC when setting up the cache in this transaction, just
3451 * skip doing the setup, we've already cleared the cache so we're safe.
3452 */
3453 if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
3454 ret = -ENOSPC;
3455 goto out_put;
3456 }
3457
3458 /*
3459 * Try to preallocate enough space based on how big the block group is.
3460 * Keep in mind this has to include any pinned space which could end up
3461 * taking up quite a bit since it's not folded into the other space
3462 * cache.
3463 */
3464 num_pages = div_u64(block_group->key.offset, SZ_256M);
3465 if (!num_pages)
3466 num_pages = 1;
3467
3468 num_pages *= 16;
3469 num_pages *= PAGE_SIZE;
3470
3471 ret = btrfs_check_data_free_space(inode, 0, num_pages);
3472 if (ret)
3473 goto out_put;
3474
3475 ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3476 num_pages, num_pages,
3477 &alloc_hint);
3478 /*
3479 * Our cache requires contiguous chunks so that we don't modify a bunch
3480 * of metadata or split extents when writing the cache out, which means
3481 * we can enospc if we are heavily fragmented in addition to just normal
3482 * out of space conditions. So if we hit this just skip setting up any
3483 * other block groups for this transaction, maybe we'll unpin enough
3484 * space the next time around.
3485 */
3486 if (!ret)
3487 dcs = BTRFS_DC_SETUP;
3488 else if (ret == -ENOSPC)
3489 set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
3490
3491 out_put:
3492 iput(inode);
3493 out_free:
3494 btrfs_release_path(path);
3495 out:
3496 spin_lock(&block_group->lock);
3497 if (!ret && dcs == BTRFS_DC_SETUP)
3498 block_group->cache_generation = trans->transid;
3499 block_group->disk_cache_state = dcs;
3500 spin_unlock(&block_group->lock);
3501
3502 return ret;
3503 }
3504
3505 int btrfs_setup_space_cache(struct btrfs_trans_handle *trans,
3506 struct btrfs_root *root)
3507 {
3508 struct btrfs_block_group_cache *cache, *tmp;
3509 struct btrfs_transaction *cur_trans = trans->transaction;
3510 struct btrfs_path *path;
3511
3512 if (list_empty(&cur_trans->dirty_bgs) ||
3513 !btrfs_test_opt(root->fs_info, SPACE_CACHE))
3514 return 0;
3515
3516 path = btrfs_alloc_path();
3517 if (!path)
3518 return -ENOMEM;
3519
3520 /* Could add new block groups, use _safe just in case */
3521 list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
3522 dirty_list) {
3523 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3524 cache_save_setup(cache, trans, path);
3525 }
3526
3527 btrfs_free_path(path);
3528 return 0;
3529 }
3530
3531 /*
3532 * transaction commit does final block group cache writeback during a
3533 * critical section where nothing is allowed to change the FS. This is
3534 * required in order for the cache to actually match the block group,
3535 * but can introduce a lot of latency into the commit.
3536 *
3537 * So, btrfs_start_dirty_block_groups is here to kick off block group
3538 * cache IO. There's a chance we'll have to redo some of it if the
3539 * block group changes again during the commit, but it greatly reduces
3540 * the commit latency by getting rid of the easy block groups while
3541 * we're still allowing others to join the commit.
3542 */
3543 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans,
3544 struct btrfs_root *root)
3545 {
3546 struct btrfs_block_group_cache *cache;
3547 struct btrfs_transaction *cur_trans = trans->transaction;
3548 int ret = 0;
3549 int should_put;
3550 struct btrfs_path *path = NULL;
3551 LIST_HEAD(dirty);
3552 struct list_head *io = &cur_trans->io_bgs;
3553 int num_started = 0;
3554 int loops = 0;
3555
3556 spin_lock(&cur_trans->dirty_bgs_lock);
3557 if (list_empty(&cur_trans->dirty_bgs)) {
3558 spin_unlock(&cur_trans->dirty_bgs_lock);
3559 return 0;
3560 }
3561 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3562 spin_unlock(&cur_trans->dirty_bgs_lock);
3563
3564 again:
3565 /*
3566 * make sure all the block groups on our dirty list actually
3567 * exist
3568 */
3569 btrfs_create_pending_block_groups(trans, root);
3570
3571 if (!path) {
3572 path = btrfs_alloc_path();
3573 if (!path)
3574 return -ENOMEM;
3575 }
3576
3577 /*
3578 * cache_write_mutex is here only to save us from balance or automatic
3579 * removal of empty block groups deleting this block group while we are
3580 * writing out the cache
3581 */
3582 mutex_lock(&trans->transaction->cache_write_mutex);
3583 while (!list_empty(&dirty)) {
3584 cache = list_first_entry(&dirty,
3585 struct btrfs_block_group_cache,
3586 dirty_list);
3587 /*
3588 * this can happen if something re-dirties a block
3589 * group that is already under IO. Just wait for it to
3590 * finish and then do it all again
3591 */
3592 if (!list_empty(&cache->io_list)) {
3593 list_del_init(&cache->io_list);
3594 btrfs_wait_cache_io(root, trans, cache,
3595 &cache->io_ctl, path,
3596 cache->key.objectid);
3597 btrfs_put_block_group(cache);
3598 }
3599
3600
3601 /*
3602 * btrfs_wait_cache_io uses the cache->dirty_list to decide
3603 * if it should update the cache_state. Don't delete
3604 * until after we wait.
3605 *
3606 * Since we're not running in the commit critical section
3607 * we need the dirty_bgs_lock to protect from update_block_group
3608 */
3609 spin_lock(&cur_trans->dirty_bgs_lock);
3610 list_del_init(&cache->dirty_list);
3611 spin_unlock(&cur_trans->dirty_bgs_lock);
3612
3613 should_put = 1;
3614
3615 cache_save_setup(cache, trans, path);
3616
3617 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
3618 cache->io_ctl.inode = NULL;
3619 ret = btrfs_write_out_cache(root, trans, cache, path);
3620 if (ret == 0 && cache->io_ctl.inode) {
3621 num_started++;
3622 should_put = 0;
3623
3624 /*
3625 * the cache_write_mutex is protecting
3626 * the io_list
3627 */
3628 list_add_tail(&cache->io_list, io);
3629 } else {
3630 /*
3631 * if we failed to write the cache, the
3632 * generation will be bad and life goes on
3633 */
3634 ret = 0;
3635 }
3636 }
3637 if (!ret) {
3638 ret = write_one_cache_group(trans, root, path, cache);
3639 /*
3640 * Our block group might still be attached to the list
3641 * of new block groups in the transaction handle of some
3642 * other task (struct btrfs_trans_handle->new_bgs). This
3643 * means its block group item isn't yet in the extent
3644 * tree. If this happens ignore the error, as we will
3645 * try again later in the critical section of the
3646 * transaction commit.
3647 */
3648 if (ret == -ENOENT) {
3649 ret = 0;
3650 spin_lock(&cur_trans->dirty_bgs_lock);
3651 if (list_empty(&cache->dirty_list)) {
3652 list_add_tail(&cache->dirty_list,
3653 &cur_trans->dirty_bgs);
3654 btrfs_get_block_group(cache);
3655 }
3656 spin_unlock(&cur_trans->dirty_bgs_lock);
3657 } else if (ret) {
3658 btrfs_abort_transaction(trans, ret);
3659 }
3660 }
3661
3662 /* if its not on the io list, we need to put the block group */
3663 if (should_put)
3664 btrfs_put_block_group(cache);
3665
3666 if (ret)
3667 break;
3668
3669 /*
3670 * Avoid blocking other tasks for too long. It might even save
3671 * us from writing caches for block groups that are going to be
3672 * removed.
3673 */
3674 mutex_unlock(&trans->transaction->cache_write_mutex);
3675 mutex_lock(&trans->transaction->cache_write_mutex);
3676 }
3677 mutex_unlock(&trans->transaction->cache_write_mutex);
3678
3679 /*
3680 * go through delayed refs for all the stuff we've just kicked off
3681 * and then loop back (just once)
3682 */
3683 ret = btrfs_run_delayed_refs(trans, root, 0);
3684 if (!ret && loops == 0) {
3685 loops++;
3686 spin_lock(&cur_trans->dirty_bgs_lock);
3687 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3688 /*
3689 * dirty_bgs_lock protects us from concurrent block group
3690 * deletes too (not just cache_write_mutex).
3691 */
3692 if (!list_empty(&dirty)) {
3693 spin_unlock(&cur_trans->dirty_bgs_lock);
3694 goto again;
3695 }
3696 spin_unlock(&cur_trans->dirty_bgs_lock);
3697 } else if (ret < 0) {
3698 btrfs_cleanup_dirty_bgs(cur_trans, root);
3699 }
3700
3701 btrfs_free_path(path);
3702 return ret;
3703 }
3704
3705 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3706 struct btrfs_root *root)
3707 {
3708 struct btrfs_block_group_cache *cache;
3709 struct btrfs_transaction *cur_trans = trans->transaction;
3710 int ret = 0;
3711 int should_put;
3712 struct btrfs_path *path;
3713 struct list_head *io = &cur_trans->io_bgs;
3714 int num_started = 0;
3715
3716 path = btrfs_alloc_path();
3717 if (!path)
3718 return -ENOMEM;
3719
3720 /*
3721 * Even though we are in the critical section of the transaction commit,
3722 * we can still have concurrent tasks adding elements to this
3723 * transaction's list of dirty block groups. These tasks correspond to
3724 * endio free space workers started when writeback finishes for a
3725 * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
3726 * allocate new block groups as a result of COWing nodes of the root
3727 * tree when updating the free space inode. The writeback for the space
3728 * caches is triggered by an earlier call to
3729 * btrfs_start_dirty_block_groups() and iterations of the following
3730 * loop.
3731 * Also we want to do the cache_save_setup first and then run the
3732 * delayed refs to make sure we have the best chance at doing this all
3733 * in one shot.
3734 */
3735 spin_lock(&cur_trans->dirty_bgs_lock);
3736 while (!list_empty(&cur_trans->dirty_bgs)) {
3737 cache = list_first_entry(&cur_trans->dirty_bgs,
3738 struct btrfs_block_group_cache,
3739 dirty_list);
3740
3741 /*
3742 * this can happen if cache_save_setup re-dirties a block
3743 * group that is already under IO. Just wait for it to
3744 * finish and then do it all again
3745 */
3746 if (!list_empty(&cache->io_list)) {
3747 spin_unlock(&cur_trans->dirty_bgs_lock);
3748 list_del_init(&cache->io_list);
3749 btrfs_wait_cache_io(root, trans, cache,
3750 &cache->io_ctl, path,
3751 cache->key.objectid);
3752 btrfs_put_block_group(cache);
3753 spin_lock(&cur_trans->dirty_bgs_lock);
3754 }
3755
3756 /*
3757 * don't remove from the dirty list until after we've waited
3758 * on any pending IO
3759 */
3760 list_del_init(&cache->dirty_list);
3761 spin_unlock(&cur_trans->dirty_bgs_lock);
3762 should_put = 1;
3763
3764 cache_save_setup(cache, trans, path);
3765
3766 if (!ret)
3767 ret = btrfs_run_delayed_refs(trans, root, (unsigned long) -1);
3768
3769 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
3770 cache->io_ctl.inode = NULL;
3771 ret = btrfs_write_out_cache(root, trans, cache, path);
3772 if (ret == 0 && cache->io_ctl.inode) {
3773 num_started++;
3774 should_put = 0;
3775 list_add_tail(&cache->io_list, io);
3776 } else {
3777 /*
3778 * if we failed to write the cache, the
3779 * generation will be bad and life goes on
3780 */
3781 ret = 0;
3782 }
3783 }
3784 if (!ret) {
3785 ret = write_one_cache_group(trans, root, path, cache);
3786 /*
3787 * One of the free space endio workers might have
3788 * created a new block group while updating a free space
3789 * cache's inode (at inode.c:btrfs_finish_ordered_io())
3790 * and hasn't released its transaction handle yet, in
3791 * which case the new block group is still attached to
3792 * its transaction handle and its creation has not
3793 * finished yet (no block group item in the extent tree
3794 * yet, etc). If this is the case, wait for all free
3795 * space endio workers to finish and retry. This is a
3796 * a very rare case so no need for a more efficient and
3797 * complex approach.
3798 */
3799 if (ret == -ENOENT) {
3800 wait_event(cur_trans->writer_wait,
3801 atomic_read(&cur_trans->num_writers) == 1);
3802 ret = write_one_cache_group(trans, root, path,
3803 cache);
3804 }
3805 if (ret)
3806 btrfs_abort_transaction(trans, ret);
3807 }
3808
3809 /* if its not on the io list, we need to put the block group */
3810 if (should_put)
3811 btrfs_put_block_group(cache);
3812 spin_lock(&cur_trans->dirty_bgs_lock);
3813 }
3814 spin_unlock(&cur_trans->dirty_bgs_lock);
3815
3816 while (!list_empty(io)) {
3817 cache = list_first_entry(io, struct btrfs_block_group_cache,
3818 io_list);
3819 list_del_init(&cache->io_list);
3820 btrfs_wait_cache_io(root, trans, cache,
3821 &cache->io_ctl, path, cache->key.objectid);
3822 btrfs_put_block_group(cache);
3823 }
3824
3825 btrfs_free_path(path);
3826 return ret;
3827 }
3828
3829 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3830 {
3831 struct btrfs_block_group_cache *block_group;
3832 int readonly = 0;
3833
3834 block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3835 if (!block_group || block_group->ro)
3836 readonly = 1;
3837 if (block_group)
3838 btrfs_put_block_group(block_group);
3839 return readonly;
3840 }
3841
3842 bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3843 {
3844 struct btrfs_block_group_cache *bg;
3845 bool ret = true;
3846
3847 bg = btrfs_lookup_block_group(fs_info, bytenr);
3848 if (!bg)
3849 return false;
3850
3851 spin_lock(&bg->lock);
3852 if (bg->ro)
3853 ret = false;
3854 else
3855 atomic_inc(&bg->nocow_writers);
3856 spin_unlock(&bg->lock);
3857
3858 /* no put on block group, done by btrfs_dec_nocow_writers */
3859 if (!ret)
3860 btrfs_put_block_group(bg);
3861
3862 return ret;
3863
3864 }
3865
3866 void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3867 {
3868 struct btrfs_block_group_cache *bg;
3869
3870 bg = btrfs_lookup_block_group(fs_info, bytenr);
3871 ASSERT(bg);
3872 if (atomic_dec_and_test(&bg->nocow_writers))
3873 wake_up_atomic_t(&bg->nocow_writers);
3874 /*
3875 * Once for our lookup and once for the lookup done by a previous call
3876 * to btrfs_inc_nocow_writers()
3877 */
3878 btrfs_put_block_group(bg);
3879 btrfs_put_block_group(bg);
3880 }
3881
3882 static int btrfs_wait_nocow_writers_atomic_t(atomic_t *a)
3883 {
3884 schedule();
3885 return 0;
3886 }
3887
3888 void btrfs_wait_nocow_writers(struct btrfs_block_group_cache *bg)
3889 {
3890 wait_on_atomic_t(&bg->nocow_writers,
3891 btrfs_wait_nocow_writers_atomic_t,
3892 TASK_UNINTERRUPTIBLE);
3893 }
3894
3895 static const char *alloc_name(u64 flags)
3896 {
3897 switch (flags) {
3898 case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
3899 return "mixed";
3900 case BTRFS_BLOCK_GROUP_METADATA:
3901 return "metadata";
3902 case BTRFS_BLOCK_GROUP_DATA:
3903 return "data";
3904 case BTRFS_BLOCK_GROUP_SYSTEM:
3905 return "system";
3906 default:
3907 WARN_ON(1);
3908 return "invalid-combination";
3909 };
3910 }
3911
3912 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3913 u64 total_bytes, u64 bytes_used,
3914 u64 bytes_readonly,
3915 struct btrfs_space_info **space_info)
3916 {
3917 struct btrfs_space_info *found;
3918 int i;
3919 int factor;
3920 int ret;
3921
3922 if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3923 BTRFS_BLOCK_GROUP_RAID10))
3924 factor = 2;
3925 else
3926 factor = 1;
3927
3928 found = __find_space_info(info, flags);
3929 if (found) {
3930 spin_lock(&found->lock);
3931 found->total_bytes += total_bytes;
3932 found->disk_total += total_bytes * factor;
3933 found->bytes_used += bytes_used;
3934 found->disk_used += bytes_used * factor;
3935 found->bytes_readonly += bytes_readonly;
3936 if (total_bytes > 0)
3937 found->full = 0;
3938 space_info_add_new_bytes(info, found, total_bytes -
3939 bytes_used - bytes_readonly);
3940 spin_unlock(&found->lock);
3941 *space_info = found;
3942 return 0;
3943 }
3944 found = kzalloc(sizeof(*found), GFP_NOFS);
3945 if (!found)
3946 return -ENOMEM;
3947
3948 ret = percpu_counter_init(&found->total_bytes_pinned, 0, GFP_KERNEL);
3949 if (ret) {
3950 kfree(found);
3951 return ret;
3952 }
3953
3954 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3955 INIT_LIST_HEAD(&found->block_groups[i]);
3956 init_rwsem(&found->groups_sem);
3957 spin_lock_init(&found->lock);
3958 found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3959 found->total_bytes = total_bytes;
3960 found->disk_total = total_bytes * factor;
3961 found->bytes_used = bytes_used;
3962 found->disk_used = bytes_used * factor;
3963 found->bytes_pinned = 0;
3964 found->bytes_reserved = 0;
3965 found->bytes_readonly = bytes_readonly;
3966 found->bytes_may_use = 0;
3967 found->full = 0;
3968 found->max_extent_size = 0;
3969 found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3970 found->chunk_alloc = 0;
3971 found->flush = 0;
3972 init_waitqueue_head(&found->wait);
3973 INIT_LIST_HEAD(&found->ro_bgs);
3974 INIT_LIST_HEAD(&found->tickets);
3975 INIT_LIST_HEAD(&found->priority_tickets);
3976
3977 ret = kobject_init_and_add(&found->kobj, &space_info_ktype,
3978 info->space_info_kobj, "%s",
3979 alloc_name(found->flags));
3980 if (ret) {
3981 kfree(found);
3982 return ret;
3983 }
3984
3985 *space_info = found;
3986 list_add_rcu(&found->list, &info->space_info);
3987 if (flags & BTRFS_BLOCK_GROUP_DATA)
3988 info->data_sinfo = found;
3989
3990 return ret;
3991 }
3992
3993 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3994 {
3995 u64 extra_flags = chunk_to_extended(flags) &
3996 BTRFS_EXTENDED_PROFILE_MASK;
3997
3998 write_seqlock(&fs_info->profiles_lock);
3999 if (flags & BTRFS_BLOCK_GROUP_DATA)
4000 fs_info->avail_data_alloc_bits |= extra_flags;
4001 if (flags & BTRFS_BLOCK_GROUP_METADATA)
4002 fs_info->avail_metadata_alloc_bits |= extra_flags;
4003 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4004 fs_info->avail_system_alloc_bits |= extra_flags;
4005 write_sequnlock(&fs_info->profiles_lock);
4006 }
4007
4008 /*
4009 * returns target flags in extended format or 0 if restripe for this
4010 * chunk_type is not in progress
4011 *
4012 * should be called with either volume_mutex or balance_lock held
4013 */
4014 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
4015 {
4016 struct btrfs_balance_control *bctl = fs_info->balance_ctl;
4017 u64 target = 0;
4018
4019 if (!bctl)
4020 return 0;
4021
4022 if (flags & BTRFS_BLOCK_GROUP_DATA &&
4023 bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4024 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
4025 } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
4026 bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4027 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
4028 } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
4029 bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4030 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
4031 }
4032
4033 return target;
4034 }
4035
4036 /*
4037 * @flags: available profiles in extended format (see ctree.h)
4038 *
4039 * Returns reduced profile in chunk format. If profile changing is in
4040 * progress (either running or paused) picks the target profile (if it's
4041 * already available), otherwise falls back to plain reducing.
4042 */
4043 static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
4044 {
4045 u64 num_devices = root->fs_info->fs_devices->rw_devices;
4046 u64 target;
4047 u64 raid_type;
4048 u64 allowed = 0;
4049
4050 /*
4051 * see if restripe for this chunk_type is in progress, if so
4052 * try to reduce to the target profile
4053 */
4054 spin_lock(&root->fs_info->balance_lock);
4055 target = get_restripe_target(root->fs_info, flags);
4056 if (target) {
4057 /* pick target profile only if it's already available */
4058 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
4059 spin_unlock(&root->fs_info->balance_lock);
4060 return extended_to_chunk(target);
4061 }
4062 }
4063 spin_unlock(&root->fs_info->balance_lock);
4064
4065 /* First, mask out the RAID levels which aren't possible */
4066 for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
4067 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
4068 allowed |= btrfs_raid_group[raid_type];
4069 }
4070 allowed &= flags;
4071
4072 if (allowed & BTRFS_BLOCK_GROUP_RAID6)
4073 allowed = BTRFS_BLOCK_GROUP_RAID6;
4074 else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
4075 allowed = BTRFS_BLOCK_GROUP_RAID5;
4076 else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
4077 allowed = BTRFS_BLOCK_GROUP_RAID10;
4078 else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
4079 allowed = BTRFS_BLOCK_GROUP_RAID1;
4080 else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
4081 allowed = BTRFS_BLOCK_GROUP_RAID0;
4082
4083 flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
4084
4085 return extended_to_chunk(flags | allowed);
4086 }
4087
4088 static u64 get_alloc_profile(struct btrfs_root *root, u64 orig_flags)
4089 {
4090 unsigned seq;
4091 u64 flags;
4092
4093 do {
4094 flags = orig_flags;
4095 seq = read_seqbegin(&root->fs_info->profiles_lock);
4096
4097 if (flags & BTRFS_BLOCK_GROUP_DATA)
4098 flags |= root->fs_info->avail_data_alloc_bits;
4099 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4100 flags |= root->fs_info->avail_system_alloc_bits;
4101 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
4102 flags |= root->fs_info->avail_metadata_alloc_bits;
4103 } while (read_seqretry(&root->fs_info->profiles_lock, seq));
4104
4105 return btrfs_reduce_alloc_profile(root, flags);
4106 }
4107
4108 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
4109 {
4110 u64 flags;
4111 u64 ret;
4112
4113 if (data)
4114 flags = BTRFS_BLOCK_GROUP_DATA;
4115 else if (root == root->fs_info->chunk_root)
4116 flags = BTRFS_BLOCK_GROUP_SYSTEM;
4117 else
4118 flags = BTRFS_BLOCK_GROUP_METADATA;
4119
4120 ret = get_alloc_profile(root, flags);
4121 return ret;
4122 }
4123
4124 int btrfs_alloc_data_chunk_ondemand(struct inode *inode, u64 bytes)
4125 {
4126 struct btrfs_space_info *data_sinfo;
4127 struct btrfs_root *root = BTRFS_I(inode)->root;
4128 struct btrfs_fs_info *fs_info = root->fs_info;
4129 u64 used;
4130 int ret = 0;
4131 int need_commit = 2;
4132 int have_pinned_space;
4133
4134 /* make sure bytes are sectorsize aligned */
4135 bytes = ALIGN(bytes, root->sectorsize);
4136
4137 if (btrfs_is_free_space_inode(inode)) {
4138 need_commit = 0;
4139 ASSERT(current->journal_info);
4140 }
4141
4142 data_sinfo = fs_info->data_sinfo;
4143 if (!data_sinfo)
4144 goto alloc;
4145
4146 again:
4147 /* make sure we have enough space to handle the data first */
4148 spin_lock(&data_sinfo->lock);
4149 used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
4150 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
4151 data_sinfo->bytes_may_use;
4152
4153 if (used + bytes > data_sinfo->total_bytes) {
4154 struct btrfs_trans_handle *trans;
4155
4156 /*
4157 * if we don't have enough free bytes in this space then we need
4158 * to alloc a new chunk.
4159 */
4160 if (!data_sinfo->full) {
4161 u64 alloc_target;
4162
4163 data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
4164 spin_unlock(&data_sinfo->lock);
4165 alloc:
4166 alloc_target = btrfs_get_alloc_profile(root, 1);
4167 /*
4168 * It is ugly that we don't call nolock join
4169 * transaction for the free space inode case here.
4170 * But it is safe because we only do the data space
4171 * reservation for the free space cache in the
4172 * transaction context, the common join transaction
4173 * just increase the counter of the current transaction
4174 * handler, doesn't try to acquire the trans_lock of
4175 * the fs.
4176 */
4177 trans = btrfs_join_transaction(root);
4178 if (IS_ERR(trans))
4179 return PTR_ERR(trans);
4180
4181 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4182 alloc_target,
4183 CHUNK_ALLOC_NO_FORCE);
4184 btrfs_end_transaction(trans, root);
4185 if (ret < 0) {
4186 if (ret != -ENOSPC)
4187 return ret;
4188 else {
4189 have_pinned_space = 1;
4190 goto commit_trans;
4191 }
4192 }
4193
4194 if (!data_sinfo)
4195 data_sinfo = fs_info->data_sinfo;
4196
4197 goto again;
4198 }
4199
4200 /*
4201 * If we don't have enough pinned space to deal with this
4202 * allocation, and no removed chunk in current transaction,
4203 * don't bother committing the transaction.
4204 */
4205 have_pinned_space = percpu_counter_compare(
4206 &data_sinfo->total_bytes_pinned,
4207 used + bytes - data_sinfo->total_bytes);
4208 spin_unlock(&data_sinfo->lock);
4209
4210 /* commit the current transaction and try again */
4211 commit_trans:
4212 if (need_commit &&
4213 !atomic_read(&root->fs_info->open_ioctl_trans)) {
4214 need_commit--;
4215
4216 if (need_commit > 0) {
4217 btrfs_start_delalloc_roots(fs_info, 0, -1);
4218 btrfs_wait_ordered_roots(fs_info, -1, 0, (u64)-1);
4219 }
4220
4221 trans = btrfs_join_transaction(root);
4222 if (IS_ERR(trans))
4223 return PTR_ERR(trans);
4224 if (have_pinned_space >= 0 ||
4225 test_bit(BTRFS_TRANS_HAVE_FREE_BGS,
4226 &trans->transaction->flags) ||
4227 need_commit > 0) {
4228 ret = btrfs_commit_transaction(trans, root);
4229 if (ret)
4230 return ret;
4231 /*
4232 * The cleaner kthread might still be doing iput
4233 * operations. Wait for it to finish so that
4234 * more space is released.
4235 */
4236 mutex_lock(&root->fs_info->cleaner_delayed_iput_mutex);
4237 mutex_unlock(&root->fs_info->cleaner_delayed_iput_mutex);
4238 goto again;
4239 } else {
4240 btrfs_end_transaction(trans, root);
4241 }
4242 }
4243
4244 trace_btrfs_space_reservation(root->fs_info,
4245 "space_info:enospc",
4246 data_sinfo->flags, bytes, 1);
4247 return -ENOSPC;
4248 }
4249 data_sinfo->bytes_may_use += bytes;
4250 trace_btrfs_space_reservation(root->fs_info, "space_info",
4251 data_sinfo->flags, bytes, 1);
4252 spin_unlock(&data_sinfo->lock);
4253
4254 return ret;
4255 }
4256
4257 /*
4258 * New check_data_free_space() with ability for precious data reservation
4259 * Will replace old btrfs_check_data_free_space(), but for patch split,
4260 * add a new function first and then replace it.
4261 */
4262 int btrfs_check_data_free_space(struct inode *inode, u64 start, u64 len)
4263 {
4264 struct btrfs_root *root = BTRFS_I(inode)->root;
4265 int ret;
4266
4267 /* align the range */
4268 len = round_up(start + len, root->sectorsize) -
4269 round_down(start, root->sectorsize);
4270 start = round_down(start, root->sectorsize);
4271
4272 ret = btrfs_alloc_data_chunk_ondemand(inode, len);
4273 if (ret < 0)
4274 return ret;
4275
4276 /* Use new btrfs_qgroup_reserve_data to reserve precious data space. */
4277 ret = btrfs_qgroup_reserve_data(inode, start, len);
4278 if (ret)
4279 btrfs_free_reserved_data_space_noquota(inode, start, len);
4280 return ret;
4281 }
4282
4283 /*
4284 * Called if we need to clear a data reservation for this inode
4285 * Normally in a error case.
4286 *
4287 * This one will *NOT* use accurate qgroup reserved space API, just for case
4288 * which we can't sleep and is sure it won't affect qgroup reserved space.
4289 * Like clear_bit_hook().
4290 */
4291 void btrfs_free_reserved_data_space_noquota(struct inode *inode, u64 start,
4292 u64 len)
4293 {
4294 struct btrfs_root *root = BTRFS_I(inode)->root;
4295 struct btrfs_space_info *data_sinfo;
4296
4297 /* Make sure the range is aligned to sectorsize */
4298 len = round_up(start + len, root->sectorsize) -
4299 round_down(start, root->sectorsize);
4300 start = round_down(start, root->sectorsize);
4301
4302 data_sinfo = root->fs_info->data_sinfo;
4303 spin_lock(&data_sinfo->lock);
4304 if (WARN_ON(data_sinfo->bytes_may_use < len))
4305 data_sinfo->bytes_may_use = 0;
4306 else
4307 data_sinfo->bytes_may_use -= len;
4308 trace_btrfs_space_reservation(root->fs_info, "space_info",
4309 data_sinfo->flags, len, 0);
4310 spin_unlock(&data_sinfo->lock);
4311 }
4312
4313 /*
4314 * Called if we need to clear a data reservation for this inode
4315 * Normally in a error case.
4316 *
4317 * This one will handle the per-inode data rsv map for accurate reserved
4318 * space framework.
4319 */
4320 void btrfs_free_reserved_data_space(struct inode *inode, u64 start, u64 len)
4321 {
4322 btrfs_free_reserved_data_space_noquota(inode, start, len);
4323 btrfs_qgroup_free_data(inode, start, len);
4324 }
4325
4326 static void force_metadata_allocation(struct btrfs_fs_info *info)
4327 {
4328 struct list_head *head = &info->space_info;
4329 struct btrfs_space_info *found;
4330
4331 rcu_read_lock();
4332 list_for_each_entry_rcu(found, head, list) {
4333 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
4334 found->force_alloc = CHUNK_ALLOC_FORCE;
4335 }
4336 rcu_read_unlock();
4337 }
4338
4339 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
4340 {
4341 return (global->size << 1);
4342 }
4343
4344 static int should_alloc_chunk(struct btrfs_root *root,
4345 struct btrfs_space_info *sinfo, int force)
4346 {
4347 struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4348 u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
4349 u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
4350 u64 thresh;
4351
4352 if (force == CHUNK_ALLOC_FORCE)
4353 return 1;
4354
4355 /*
4356 * We need to take into account the global rsv because for all intents
4357 * and purposes it's used space. Don't worry about locking the
4358 * global_rsv, it doesn't change except when the transaction commits.
4359 */
4360 if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
4361 num_allocated += calc_global_rsv_need_space(global_rsv);
4362
4363 /*
4364 * in limited mode, we want to have some free space up to
4365 * about 1% of the FS size.
4366 */
4367 if (force == CHUNK_ALLOC_LIMITED) {
4368 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
4369 thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
4370
4371 if (num_bytes - num_allocated < thresh)
4372 return 1;
4373 }
4374
4375 if (num_allocated + SZ_2M < div_factor(num_bytes, 8))
4376 return 0;
4377 return 1;
4378 }
4379
4380 static u64 get_profile_num_devs(struct btrfs_root *root, u64 type)
4381 {
4382 u64 num_dev;
4383
4384 if (type & (BTRFS_BLOCK_GROUP_RAID10 |
4385 BTRFS_BLOCK_GROUP_RAID0 |
4386 BTRFS_BLOCK_GROUP_RAID5 |
4387 BTRFS_BLOCK_GROUP_RAID6))
4388 num_dev = root->fs_info->fs_devices->rw_devices;
4389 else if (type & BTRFS_BLOCK_GROUP_RAID1)
4390 num_dev = 2;
4391 else
4392 num_dev = 1; /* DUP or single */
4393
4394 return num_dev;
4395 }
4396
4397 /*
4398 * If @is_allocation is true, reserve space in the system space info necessary
4399 * for allocating a chunk, otherwise if it's false, reserve space necessary for
4400 * removing a chunk.
4401 */
4402 void check_system_chunk(struct btrfs_trans_handle *trans,
4403 struct btrfs_root *root,
4404 u64 type)
4405 {
4406 struct btrfs_space_info *info;
4407 u64 left;
4408 u64 thresh;
4409 int ret = 0;
4410 u64 num_devs;
4411
4412 /*
4413 * Needed because we can end up allocating a system chunk and for an
4414 * atomic and race free space reservation in the chunk block reserve.
4415 */
4416 ASSERT(mutex_is_locked(&root->fs_info->chunk_mutex));
4417
4418 info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4419 spin_lock(&info->lock);
4420 left = info->total_bytes - info->bytes_used - info->bytes_pinned -
4421 info->bytes_reserved - info->bytes_readonly -
4422 info->bytes_may_use;
4423 spin_unlock(&info->lock);
4424
4425 num_devs = get_profile_num_devs(root, type);
4426
4427 /* num_devs device items to update and 1 chunk item to add or remove */
4428 thresh = btrfs_calc_trunc_metadata_size(root, num_devs) +
4429 btrfs_calc_trans_metadata_size(root, 1);
4430
4431 if (left < thresh && btrfs_test_opt(root->fs_info, ENOSPC_DEBUG)) {
4432 btrfs_info(root->fs_info, "left=%llu, need=%llu, flags=%llu",
4433 left, thresh, type);
4434 dump_space_info(root->fs_info, info, 0, 0);
4435 }
4436
4437 if (left < thresh) {
4438 u64 flags;
4439
4440 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
4441 /*
4442 * Ignore failure to create system chunk. We might end up not
4443 * needing it, as we might not need to COW all nodes/leafs from
4444 * the paths we visit in the chunk tree (they were already COWed
4445 * or created in the current transaction for example).
4446 */
4447 ret = btrfs_alloc_chunk(trans, root, flags);
4448 }
4449
4450 if (!ret) {
4451 ret = btrfs_block_rsv_add(root->fs_info->chunk_root,
4452 &root->fs_info->chunk_block_rsv,
4453 thresh, BTRFS_RESERVE_NO_FLUSH);
4454 if (!ret)
4455 trans->chunk_bytes_reserved += thresh;
4456 }
4457 }
4458
4459 /*
4460 * If force is CHUNK_ALLOC_FORCE:
4461 * - return 1 if it successfully allocates a chunk,
4462 * - return errors including -ENOSPC otherwise.
4463 * If force is NOT CHUNK_ALLOC_FORCE:
4464 * - return 0 if it doesn't need to allocate a new chunk,
4465 * - return 1 if it successfully allocates a chunk,
4466 * - return errors including -ENOSPC otherwise.
4467 */
4468 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
4469 struct btrfs_root *extent_root, u64 flags, int force)
4470 {
4471 struct btrfs_space_info *space_info;
4472 struct btrfs_fs_info *fs_info = extent_root->fs_info;
4473 int wait_for_alloc = 0;
4474 int ret = 0;
4475
4476 /* Don't re-enter if we're already allocating a chunk */
4477 if (trans->allocating_chunk)
4478 return -ENOSPC;
4479
4480 space_info = __find_space_info(extent_root->fs_info, flags);
4481 if (!space_info) {
4482 ret = update_space_info(extent_root->fs_info, flags,
4483 0, 0, 0, &space_info);
4484 BUG_ON(ret); /* -ENOMEM */
4485 }
4486 BUG_ON(!space_info); /* Logic error */
4487
4488 again:
4489 spin_lock(&space_info->lock);
4490 if (force < space_info->force_alloc)
4491 force = space_info->force_alloc;
4492 if (space_info->full) {
4493 if (should_alloc_chunk(extent_root, space_info, force))
4494 ret = -ENOSPC;
4495 else
4496 ret = 0;
4497 spin_unlock(&space_info->lock);
4498 return ret;
4499 }
4500
4501 if (!should_alloc_chunk(extent_root, space_info, force)) {
4502 spin_unlock(&space_info->lock);
4503 return 0;
4504 } else if (space_info->chunk_alloc) {
4505 wait_for_alloc = 1;
4506 } else {
4507 space_info->chunk_alloc = 1;
4508 }
4509
4510 spin_unlock(&space_info->lock);
4511
4512 mutex_lock(&fs_info->chunk_mutex);
4513
4514 /*
4515 * The chunk_mutex is held throughout the entirety of a chunk
4516 * allocation, so once we've acquired the chunk_mutex we know that the
4517 * other guy is done and we need to recheck and see if we should
4518 * allocate.
4519 */
4520 if (wait_for_alloc) {
4521 mutex_unlock(&fs_info->chunk_mutex);
4522 wait_for_alloc = 0;
4523 goto again;
4524 }
4525
4526 trans->allocating_chunk = true;
4527
4528 /*
4529 * If we have mixed data/metadata chunks we want to make sure we keep
4530 * allocating mixed chunks instead of individual chunks.
4531 */
4532 if (btrfs_mixed_space_info(space_info))
4533 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
4534
4535 /*
4536 * if we're doing a data chunk, go ahead and make sure that
4537 * we keep a reasonable number of metadata chunks allocated in the
4538 * FS as well.
4539 */
4540 if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
4541 fs_info->data_chunk_allocations++;
4542 if (!(fs_info->data_chunk_allocations %
4543 fs_info->metadata_ratio))
4544 force_metadata_allocation(fs_info);
4545 }
4546
4547 /*
4548 * Check if we have enough space in SYSTEM chunk because we may need
4549 * to update devices.
4550 */
4551 check_system_chunk(trans, extent_root, flags);
4552
4553 ret = btrfs_alloc_chunk(trans, extent_root, flags);
4554 trans->allocating_chunk = false;
4555
4556 spin_lock(&space_info->lock);
4557 if (ret < 0 && ret != -ENOSPC)
4558 goto out;
4559 if (ret)
4560 space_info->full = 1;
4561 else
4562 ret = 1;
4563
4564 space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4565 out:
4566 space_info->chunk_alloc = 0;
4567 spin_unlock(&space_info->lock);
4568 mutex_unlock(&fs_info->chunk_mutex);
4569 /*
4570 * When we allocate a new chunk we reserve space in the chunk block
4571 * reserve to make sure we can COW nodes/leafs in the chunk tree or
4572 * add new nodes/leafs to it if we end up needing to do it when
4573 * inserting the chunk item and updating device items as part of the
4574 * second phase of chunk allocation, performed by
4575 * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
4576 * large number of new block groups to create in our transaction
4577 * handle's new_bgs list to avoid exhausting the chunk block reserve
4578 * in extreme cases - like having a single transaction create many new
4579 * block groups when starting to write out the free space caches of all
4580 * the block groups that were made dirty during the lifetime of the
4581 * transaction.
4582 */
4583 if (trans->can_flush_pending_bgs &&
4584 trans->chunk_bytes_reserved >= (u64)SZ_2M) {
4585 btrfs_create_pending_block_groups(trans, extent_root);
4586 btrfs_trans_release_chunk_metadata(trans);
4587 }
4588 return ret;
4589 }
4590
4591 static int can_overcommit(struct btrfs_root *root,
4592 struct btrfs_space_info *space_info, u64 bytes,
4593 enum btrfs_reserve_flush_enum flush)
4594 {
4595 struct btrfs_block_rsv *global_rsv;
4596 u64 profile;
4597 u64 space_size;
4598 u64 avail;
4599 u64 used;
4600
4601 /* Don't overcommit when in mixed mode. */
4602 if (space_info->flags & BTRFS_BLOCK_GROUP_DATA)
4603 return 0;
4604
4605 BUG_ON(root->fs_info == NULL);
4606 global_rsv = &root->fs_info->global_block_rsv;
4607 profile = btrfs_get_alloc_profile(root, 0);
4608 used = space_info->bytes_used + space_info->bytes_reserved +
4609 space_info->bytes_pinned + space_info->bytes_readonly;
4610
4611 /*
4612 * We only want to allow over committing if we have lots of actual space
4613 * free, but if we don't have enough space to handle the global reserve
4614 * space then we could end up having a real enospc problem when trying
4615 * to allocate a chunk or some other such important allocation.
4616 */
4617 spin_lock(&global_rsv->lock);
4618 space_size = calc_global_rsv_need_space(global_rsv);
4619 spin_unlock(&global_rsv->lock);
4620 if (used + space_size >= space_info->total_bytes)
4621 return 0;
4622
4623 used += space_info->bytes_may_use;
4624
4625 spin_lock(&root->fs_info->free_chunk_lock);
4626 avail = root->fs_info->free_chunk_space;
4627 spin_unlock(&root->fs_info->free_chunk_lock);
4628
4629 /*
4630 * If we have dup, raid1 or raid10 then only half of the free
4631 * space is actually useable. For raid56, the space info used
4632 * doesn't include the parity drive, so we don't have to
4633 * change the math
4634 */
4635 if (profile & (BTRFS_BLOCK_GROUP_DUP |
4636 BTRFS_BLOCK_GROUP_RAID1 |
4637 BTRFS_BLOCK_GROUP_RAID10))
4638 avail >>= 1;
4639
4640 /*
4641 * If we aren't flushing all things, let us overcommit up to
4642 * 1/2th of the space. If we can flush, don't let us overcommit
4643 * too much, let it overcommit up to 1/8 of the space.
4644 */
4645 if (flush == BTRFS_RESERVE_FLUSH_ALL)
4646 avail >>= 3;
4647 else
4648 avail >>= 1;
4649
4650 if (used + bytes < space_info->total_bytes + avail)
4651 return 1;
4652 return 0;
4653 }
4654
4655 static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
4656 unsigned long nr_pages, int nr_items)
4657 {
4658 struct super_block *sb = root->fs_info->sb;
4659
4660 if (down_read_trylock(&sb->s_umount)) {
4661 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
4662 up_read(&sb->s_umount);
4663 } else {
4664 /*
4665 * We needn't worry the filesystem going from r/w to r/o though
4666 * we don't acquire ->s_umount mutex, because the filesystem
4667 * should guarantee the delalloc inodes list be empty after
4668 * the filesystem is readonly(all dirty pages are written to
4669 * the disk).
4670 */
4671 btrfs_start_delalloc_roots(root->fs_info, 0, nr_items);
4672 if (!current->journal_info)
4673 btrfs_wait_ordered_roots(root->fs_info, nr_items,
4674 0, (u64)-1);
4675 }
4676 }
4677
4678 static inline int calc_reclaim_items_nr(struct btrfs_root *root, u64 to_reclaim)
4679 {
4680 u64 bytes;
4681 int nr;
4682
4683 bytes = btrfs_calc_trans_metadata_size(root, 1);
4684 nr = (int)div64_u64(to_reclaim, bytes);
4685 if (!nr)
4686 nr = 1;
4687 return nr;
4688 }
4689
4690 #define EXTENT_SIZE_PER_ITEM SZ_256K
4691
4692 /*
4693 * shrink metadata reservation for delalloc
4694 */
4695 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
4696 bool wait_ordered)
4697 {
4698 struct btrfs_block_rsv *block_rsv;
4699 struct btrfs_space_info *space_info;
4700 struct btrfs_trans_handle *trans;
4701 u64 delalloc_bytes;
4702 u64 max_reclaim;
4703 long time_left;
4704 unsigned long nr_pages;
4705 int loops;
4706 int items;
4707 enum btrfs_reserve_flush_enum flush;
4708
4709 /* Calc the number of the pages we need flush for space reservation */
4710 items = calc_reclaim_items_nr(root, to_reclaim);
4711 to_reclaim = (u64)items * EXTENT_SIZE_PER_ITEM;
4712
4713 trans = (struct btrfs_trans_handle *)current->journal_info;
4714 block_rsv = &root->fs_info->delalloc_block_rsv;
4715 space_info = block_rsv->space_info;
4716
4717 delalloc_bytes = percpu_counter_sum_positive(
4718 &root->fs_info->delalloc_bytes);
4719 if (delalloc_bytes == 0) {
4720 if (trans)
4721 return;
4722 if (wait_ordered)
4723 btrfs_wait_ordered_roots(root->fs_info, items,
4724 0, (u64)-1);
4725 return;
4726 }
4727
4728 loops = 0;
4729 while (delalloc_bytes && loops < 3) {
4730 max_reclaim = min(delalloc_bytes, to_reclaim);
4731 nr_pages = max_reclaim >> PAGE_SHIFT;
4732 btrfs_writeback_inodes_sb_nr(root, nr_pages, items);
4733 /*
4734 * We need to wait for the async pages to actually start before
4735 * we do anything.
4736 */
4737 max_reclaim = atomic_read(&root->fs_info->async_delalloc_pages);
4738 if (!max_reclaim)
4739 goto skip_async;
4740
4741 if (max_reclaim <= nr_pages)
4742 max_reclaim = 0;
4743 else
4744 max_reclaim -= nr_pages;
4745
4746 wait_event(root->fs_info->async_submit_wait,
4747 atomic_read(&root->fs_info->async_delalloc_pages) <=
4748 (int)max_reclaim);
4749 skip_async:
4750 if (!trans)
4751 flush = BTRFS_RESERVE_FLUSH_ALL;
4752 else
4753 flush = BTRFS_RESERVE_NO_FLUSH;
4754 spin_lock(&space_info->lock);
4755 if (can_overcommit(root, space_info, orig, flush)) {
4756 spin_unlock(&space_info->lock);
4757 break;
4758 }
4759 if (list_empty(&space_info->tickets) &&
4760 list_empty(&space_info->priority_tickets)) {
4761 spin_unlock(&space_info->lock);
4762 break;
4763 }
4764 spin_unlock(&space_info->lock);
4765
4766 loops++;
4767 if (wait_ordered && !trans) {
4768 btrfs_wait_ordered_roots(root->fs_info, items,
4769 0, (u64)-1);
4770 } else {
4771 time_left = schedule_timeout_killable(1);
4772 if (time_left)
4773 break;
4774 }
4775 delalloc_bytes = percpu_counter_sum_positive(
4776 &root->fs_info->delalloc_bytes);
4777 }
4778 }
4779
4780 /**
4781 * maybe_commit_transaction - possibly commit the transaction if its ok to
4782 * @root - the root we're allocating for
4783 * @bytes - the number of bytes we want to reserve
4784 * @force - force the commit
4785 *
4786 * This will check to make sure that committing the transaction will actually
4787 * get us somewhere and then commit the transaction if it does. Otherwise it
4788 * will return -ENOSPC.
4789 */
4790 static int may_commit_transaction(struct btrfs_root *root,
4791 struct btrfs_space_info *space_info,
4792 u64 bytes, int force)
4793 {
4794 struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
4795 struct btrfs_trans_handle *trans;
4796
4797 trans = (struct btrfs_trans_handle *)current->journal_info;
4798 if (trans)
4799 return -EAGAIN;
4800
4801 if (force)
4802 goto commit;
4803
4804 /* See if there is enough pinned space to make this reservation */
4805 if (percpu_counter_compare(&space_info->total_bytes_pinned,
4806 bytes) >= 0)
4807 goto commit;
4808
4809 /*
4810 * See if there is some space in the delayed insertion reservation for
4811 * this reservation.
4812 */
4813 if (space_info != delayed_rsv->space_info)
4814 return -ENOSPC;
4815
4816 spin_lock(&delayed_rsv->lock);
4817 if (percpu_counter_compare(&space_info->total_bytes_pinned,
4818 bytes - delayed_rsv->size) >= 0) {
4819 spin_unlock(&delayed_rsv->lock);
4820 return -ENOSPC;
4821 }
4822 spin_unlock(&delayed_rsv->lock);
4823
4824 commit:
4825 trans = btrfs_join_transaction(root);
4826 if (IS_ERR(trans))
4827 return -ENOSPC;
4828
4829 return btrfs_commit_transaction(trans, root);
4830 }
4831
4832 struct reserve_ticket {
4833 u64 bytes;
4834 int error;
4835 struct list_head list;
4836 wait_queue_head_t wait;
4837 };
4838
4839 static int flush_space(struct btrfs_root *root,
4840 struct btrfs_space_info *space_info, u64 num_bytes,
4841 u64 orig_bytes, int state)
4842 {
4843 struct btrfs_trans_handle *trans;
4844 int nr;
4845 int ret = 0;
4846
4847 switch (state) {
4848 case FLUSH_DELAYED_ITEMS_NR:
4849 case FLUSH_DELAYED_ITEMS:
4850 if (state == FLUSH_DELAYED_ITEMS_NR)
4851 nr = calc_reclaim_items_nr(root, num_bytes) * 2;
4852 else
4853 nr = -1;
4854
4855 trans = btrfs_join_transaction(root);
4856 if (IS_ERR(trans)) {
4857 ret = PTR_ERR(trans);
4858 break;
4859 }
4860 ret = btrfs_run_delayed_items_nr(trans, root, nr);
4861 btrfs_end_transaction(trans, root);
4862 break;
4863 case FLUSH_DELALLOC:
4864 case FLUSH_DELALLOC_WAIT:
4865 shrink_delalloc(root, num_bytes * 2, orig_bytes,
4866 state == FLUSH_DELALLOC_WAIT);
4867 break;
4868 case ALLOC_CHUNK:
4869 trans = btrfs_join_transaction(root);
4870 if (IS_ERR(trans)) {
4871 ret = PTR_ERR(trans);
4872 break;
4873 }
4874 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4875 btrfs_get_alloc_profile(root, 0),
4876 CHUNK_ALLOC_NO_FORCE);
4877 btrfs_end_transaction(trans, root);
4878 if (ret > 0 || ret == -ENOSPC)
4879 ret = 0;
4880 break;
4881 case COMMIT_TRANS:
4882 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
4883 break;
4884 default:
4885 ret = -ENOSPC;
4886 break;
4887 }
4888
4889 trace_btrfs_flush_space(root->fs_info, space_info->flags, num_bytes,
4890 orig_bytes, state, ret);
4891 return ret;
4892 }
4893
4894 static inline u64
4895 btrfs_calc_reclaim_metadata_size(struct btrfs_root *root,
4896 struct btrfs_space_info *space_info)
4897 {
4898 struct reserve_ticket *ticket;
4899 u64 used;
4900 u64 expected;
4901 u64 to_reclaim = 0;
4902
4903 list_for_each_entry(ticket, &space_info->tickets, list)
4904 to_reclaim += ticket->bytes;
4905 list_for_each_entry(ticket, &space_info->priority_tickets, list)
4906 to_reclaim += ticket->bytes;
4907 if (to_reclaim)
4908 return to_reclaim;
4909
4910 to_reclaim = min_t(u64, num_online_cpus() * SZ_1M, SZ_16M);
4911 if (can_overcommit(root, space_info, to_reclaim,
4912 BTRFS_RESERVE_FLUSH_ALL))
4913 return 0;
4914
4915 used = space_info->bytes_used + space_info->bytes_reserved +
4916 space_info->bytes_pinned + space_info->bytes_readonly +
4917 space_info->bytes_may_use;
4918 if (can_overcommit(root, space_info, SZ_1M, BTRFS_RESERVE_FLUSH_ALL))
4919 expected = div_factor_fine(space_info->total_bytes, 95);
4920 else
4921 expected = div_factor_fine(space_info->total_bytes, 90);
4922
4923 if (used > expected)
4924 to_reclaim = used - expected;
4925 else
4926 to_reclaim = 0;
4927 to_reclaim = min(to_reclaim, space_info->bytes_may_use +
4928 space_info->bytes_reserved);
4929 return to_reclaim;
4930 }
4931
4932 static inline int need_do_async_reclaim(struct btrfs_space_info *space_info,
4933 struct btrfs_root *root, u64 used)
4934 {
4935 u64 thresh = div_factor_fine(space_info->total_bytes, 98);
4936
4937 /* If we're just plain full then async reclaim just slows us down. */
4938 if ((space_info->bytes_used + space_info->bytes_reserved) >= thresh)
4939 return 0;
4940
4941 if (!btrfs_calc_reclaim_metadata_size(root, space_info))
4942 return 0;
4943
4944 return (used >= thresh && !btrfs_fs_closing(root->fs_info) &&
4945 !test_bit(BTRFS_FS_STATE_REMOUNTING,
4946 &root->fs_info->fs_state));
4947 }
4948
4949 static void wake_all_tickets(struct list_head *head)
4950 {
4951 struct reserve_ticket *ticket;
4952
4953 while (!list_empty(head)) {
4954 ticket = list_first_entry(head, struct reserve_ticket, list);
4955 list_del_init(&ticket->list);
4956 ticket->error = -ENOSPC;
4957 wake_up(&ticket->wait);
4958 }
4959 }
4960
4961 /*
4962 * This is for normal flushers, we can wait all goddamned day if we want to. We
4963 * will loop and continuously try to flush as long as we are making progress.
4964 * We count progress as clearing off tickets each time we have to loop.
4965 */
4966 static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
4967 {
4968 struct btrfs_fs_info *fs_info;
4969 struct btrfs_space_info *space_info;
4970 u64 to_reclaim;
4971 int flush_state;
4972 int commit_cycles = 0;
4973 u64 last_tickets_id;
4974
4975 fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
4976 space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4977
4978 spin_lock(&space_info->lock);
4979 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
4980 space_info);
4981 if (!to_reclaim) {
4982 space_info->flush = 0;
4983 spin_unlock(&space_info->lock);
4984 return;
4985 }
4986 last_tickets_id = space_info->tickets_id;
4987 spin_unlock(&space_info->lock);
4988
4989 flush_state = FLUSH_DELAYED_ITEMS_NR;
4990 do {
4991 struct reserve_ticket *ticket;
4992 int ret;
4993
4994 ret = flush_space(fs_info->fs_root, space_info, to_reclaim,
4995 to_reclaim, flush_state);
4996 spin_lock(&space_info->lock);
4997 if (list_empty(&space_info->tickets)) {
4998 space_info->flush = 0;
4999 spin_unlock(&space_info->lock);
5000 return;
5001 }
5002 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
5003 space_info);
5004 ticket = list_first_entry(&space_info->tickets,
5005 struct reserve_ticket, list);
5006 if (last_tickets_id == space_info->tickets_id) {
5007 flush_state++;
5008 } else {
5009 last_tickets_id = space_info->tickets_id;
5010 flush_state = FLUSH_DELAYED_ITEMS_NR;
5011 if (commit_cycles)
5012 commit_cycles--;
5013 }
5014
5015 if (flush_state > COMMIT_TRANS) {
5016 commit_cycles++;
5017 if (commit_cycles > 2) {
5018 wake_all_tickets(&space_info->tickets);
5019 space_info->flush = 0;
5020 } else {
5021 flush_state = FLUSH_DELAYED_ITEMS_NR;
5022 }
5023 }
5024 spin_unlock(&space_info->lock);
5025 } while (flush_state <= COMMIT_TRANS);
5026 }
5027
5028 void btrfs_init_async_reclaim_work(struct work_struct *work)
5029 {
5030 INIT_WORK(work, btrfs_async_reclaim_metadata_space);
5031 }
5032
5033 static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
5034 struct btrfs_space_info *space_info,
5035 struct reserve_ticket *ticket)
5036 {
5037 u64 to_reclaim;
5038 int flush_state = FLUSH_DELAYED_ITEMS_NR;
5039
5040 spin_lock(&space_info->lock);
5041 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
5042 space_info);
5043 if (!to_reclaim) {
5044 spin_unlock(&space_info->lock);
5045 return;
5046 }
5047 spin_unlock(&space_info->lock);
5048
5049 do {
5050 flush_space(fs_info->fs_root, space_info, to_reclaim,
5051 to_reclaim, flush_state);
5052 flush_state++;
5053 spin_lock(&space_info->lock);
5054 if (ticket->bytes == 0) {
5055 spin_unlock(&space_info->lock);
5056 return;
5057 }
5058 spin_unlock(&space_info->lock);
5059
5060 /*
5061 * Priority flushers can't wait on delalloc without
5062 * deadlocking.
5063 */
5064 if (flush_state == FLUSH_DELALLOC ||
5065 flush_state == FLUSH_DELALLOC_WAIT)
5066 flush_state = ALLOC_CHUNK;
5067 } while (flush_state < COMMIT_TRANS);
5068 }
5069
5070 static int wait_reserve_ticket(struct btrfs_fs_info *fs_info,
5071 struct btrfs_space_info *space_info,
5072 struct reserve_ticket *ticket, u64 orig_bytes)
5073
5074 {
5075 DEFINE_WAIT(wait);
5076 int ret = 0;
5077
5078 spin_lock(&space_info->lock);
5079 while (ticket->bytes > 0 && ticket->error == 0) {
5080 ret = prepare_to_wait_event(&ticket->wait, &wait, TASK_KILLABLE);
5081 if (ret) {
5082 ret = -EINTR;
5083 break;
5084 }
5085 spin_unlock(&space_info->lock);
5086
5087 schedule();
5088
5089 finish_wait(&ticket->wait, &wait);
5090 spin_lock(&space_info->lock);
5091 }
5092 if (!ret)
5093 ret = ticket->error;
5094 if (!list_empty(&ticket->list))
5095 list_del_init(&ticket->list);
5096 if (ticket->bytes && ticket->bytes < orig_bytes) {
5097 u64 num_bytes = orig_bytes - ticket->bytes;
5098 space_info->bytes_may_use -= num_bytes;
5099 trace_btrfs_space_reservation(fs_info, "space_info",
5100 space_info->flags, num_bytes, 0);
5101 }
5102 spin_unlock(&space_info->lock);
5103
5104 return ret;
5105 }
5106
5107 /**
5108 * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5109 * @root - the root we're allocating for
5110 * @space_info - the space info we want to allocate from
5111 * @orig_bytes - the number of bytes we want
5112 * @flush - whether or not we can flush to make our reservation
5113 *
5114 * This will reserve orig_bytes number of bytes from the space info associated
5115 * with the block_rsv. If there is not enough space it will make an attempt to
5116 * flush out space to make room. It will do this by flushing delalloc if
5117 * possible or committing the transaction. If flush is 0 then no attempts to
5118 * regain reservations will be made and this will fail if there is not enough
5119 * space already.
5120 */
5121 static int __reserve_metadata_bytes(struct btrfs_root *root,
5122 struct btrfs_space_info *space_info,
5123 u64 orig_bytes,
5124 enum btrfs_reserve_flush_enum flush)
5125 {
5126 struct reserve_ticket ticket;
5127 u64 used;
5128 int ret = 0;
5129
5130 ASSERT(orig_bytes);
5131 ASSERT(!current->journal_info || flush != BTRFS_RESERVE_FLUSH_ALL);
5132
5133 spin_lock(&space_info->lock);
5134 ret = -ENOSPC;
5135 used = space_info->bytes_used + space_info->bytes_reserved +
5136 space_info->bytes_pinned + space_info->bytes_readonly +
5137 space_info->bytes_may_use;
5138
5139 /*
5140 * If we have enough space then hooray, make our reservation and carry
5141 * on. If not see if we can overcommit, and if we can, hooray carry on.
5142 * If not things get more complicated.
5143 */
5144 if (used + orig_bytes <= space_info->total_bytes) {
5145 space_info->bytes_may_use += orig_bytes;
5146 trace_btrfs_space_reservation(root->fs_info, "space_info",
5147 space_info->flags, orig_bytes,
5148 1);
5149 ret = 0;
5150 } else if (can_overcommit(root, space_info, orig_bytes, flush)) {
5151 space_info->bytes_may_use += orig_bytes;
5152 trace_btrfs_space_reservation(root->fs_info, "space_info",
5153 space_info->flags, orig_bytes,
5154 1);
5155 ret = 0;
5156 }
5157
5158 /*
5159 * If we couldn't make a reservation then setup our reservation ticket
5160 * and kick the async worker if it's not already running.
5161 *
5162 * If we are a priority flusher then we just need to add our ticket to
5163 * the list and we will do our own flushing further down.
5164 */
5165 if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
5166 ticket.bytes = orig_bytes;
5167 ticket.error = 0;
5168 init_waitqueue_head(&ticket.wait);
5169 if (flush == BTRFS_RESERVE_FLUSH_ALL) {
5170 list_add_tail(&ticket.list, &space_info->tickets);
5171 if (!space_info->flush) {
5172 space_info->flush = 1;
5173 trace_btrfs_trigger_flush(root->fs_info,
5174 space_info->flags,
5175 orig_bytes, flush,
5176 "enospc");
5177 queue_work(system_unbound_wq,
5178 &root->fs_info->async_reclaim_work);
5179 }
5180 } else {
5181 list_add_tail(&ticket.list,
5182 &space_info->priority_tickets);
5183 }
5184 } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
5185 used += orig_bytes;
5186 /*
5187 * We will do the space reservation dance during log replay,
5188 * which means we won't have fs_info->fs_root set, so don't do
5189 * the async reclaim as we will panic.
5190 */
5191 if (!test_bit(BTRFS_FS_LOG_RECOVERING, &root->fs_info->flags) &&
5192 need_do_async_reclaim(space_info, root, used) &&
5193 !work_busy(&root->fs_info->async_reclaim_work)) {
5194 trace_btrfs_trigger_flush(root->fs_info,
5195 space_info->flags,
5196 orig_bytes, flush,
5197 "preempt");
5198 queue_work(system_unbound_wq,
5199 &root->fs_info->async_reclaim_work);
5200 }
5201 }
5202 spin_unlock(&space_info->lock);
5203 if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
5204 return ret;
5205
5206 if (flush == BTRFS_RESERVE_FLUSH_ALL)
5207 return wait_reserve_ticket(root->fs_info, space_info, &ticket,
5208 orig_bytes);
5209
5210 ret = 0;
5211 priority_reclaim_metadata_space(root->fs_info, space_info, &ticket);
5212 spin_lock(&space_info->lock);
5213 if (ticket.bytes) {
5214 if (ticket.bytes < orig_bytes) {
5215 u64 num_bytes = orig_bytes - ticket.bytes;
5216 space_info->bytes_may_use -= num_bytes;
5217 trace_btrfs_space_reservation(root->fs_info,
5218 "space_info", space_info->flags,
5219 num_bytes, 0);
5220
5221 }
5222 list_del_init(&ticket.list);
5223 ret = -ENOSPC;
5224 }
5225 spin_unlock(&space_info->lock);
5226 ASSERT(list_empty(&ticket.list));
5227 return ret;
5228 }
5229
5230 /**
5231 * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5232 * @root - the root we're allocating for
5233 * @block_rsv - the block_rsv we're allocating for
5234 * @orig_bytes - the number of bytes we want
5235 * @flush - whether or not we can flush to make our reservation
5236 *
5237 * This will reserve orgi_bytes number of bytes from the space info associated
5238 * with the block_rsv. If there is not enough space it will make an attempt to
5239 * flush out space to make room. It will do this by flushing delalloc if
5240 * possible or committing the transaction. If flush is 0 then no attempts to
5241 * regain reservations will be made and this will fail if there is not enough
5242 * space already.
5243 */
5244 static int reserve_metadata_bytes(struct btrfs_root *root,
5245 struct btrfs_block_rsv *block_rsv,
5246 u64 orig_bytes,
5247 enum btrfs_reserve_flush_enum flush)
5248 {
5249 int ret;
5250
5251 ret = __reserve_metadata_bytes(root, block_rsv->space_info, orig_bytes,
5252 flush);
5253 if (ret == -ENOSPC &&
5254 unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
5255 struct btrfs_block_rsv *global_rsv =
5256 &root->fs_info->global_block_rsv;
5257
5258 if (block_rsv != global_rsv &&
5259 !block_rsv_use_bytes(global_rsv, orig_bytes))
5260 ret = 0;
5261 }
5262 if (ret == -ENOSPC)
5263 trace_btrfs_space_reservation(root->fs_info,
5264 "space_info:enospc",
5265 block_rsv->space_info->flags,
5266 orig_bytes, 1);
5267 return ret;
5268 }
5269
5270 static struct btrfs_block_rsv *get_block_rsv(
5271 const struct btrfs_trans_handle *trans,
5272 const struct btrfs_root *root)
5273 {
5274 struct btrfs_block_rsv *block_rsv = NULL;
5275
5276 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
5277 (root == root->fs_info->csum_root && trans->adding_csums) ||
5278 (root == root->fs_info->uuid_root))
5279 block_rsv = trans->block_rsv;
5280
5281 if (!block_rsv)
5282 block_rsv = root->block_rsv;
5283
5284 if (!block_rsv)
5285 block_rsv = &root->fs_info->empty_block_rsv;
5286
5287 return block_rsv;
5288 }
5289
5290 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
5291 u64 num_bytes)
5292 {
5293 int ret = -ENOSPC;
5294 spin_lock(&block_rsv->lock);
5295 if (block_rsv->reserved >= num_bytes) {
5296 block_rsv->reserved -= num_bytes;
5297 if (block_rsv->reserved < block_rsv->size)
5298 block_rsv->full = 0;
5299 ret = 0;
5300 }
5301 spin_unlock(&block_rsv->lock);
5302 return ret;
5303 }
5304
5305 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
5306 u64 num_bytes, int update_size)
5307 {
5308 spin_lock(&block_rsv->lock);
5309 block_rsv->reserved += num_bytes;
5310 if (update_size)
5311 block_rsv->size += num_bytes;
5312 else if (block_rsv->reserved >= block_rsv->size)
5313 block_rsv->full = 1;
5314 spin_unlock(&block_rsv->lock);
5315 }
5316
5317 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
5318 struct btrfs_block_rsv *dest, u64 num_bytes,
5319 int min_factor)
5320 {
5321 struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5322 u64 min_bytes;
5323
5324 if (global_rsv->space_info != dest->space_info)
5325 return -ENOSPC;
5326
5327 spin_lock(&global_rsv->lock);
5328 min_bytes = div_factor(global_rsv->size, min_factor);
5329 if (global_rsv->reserved < min_bytes + num_bytes) {
5330 spin_unlock(&global_rsv->lock);
5331 return -ENOSPC;
5332 }
5333 global_rsv->reserved -= num_bytes;
5334 if (global_rsv->reserved < global_rsv->size)
5335 global_rsv->full = 0;
5336 spin_unlock(&global_rsv->lock);
5337
5338 block_rsv_add_bytes(dest, num_bytes, 1);
5339 return 0;
5340 }
5341
5342 /*
5343 * This is for space we already have accounted in space_info->bytes_may_use, so
5344 * basically when we're returning space from block_rsv's.
5345 */
5346 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
5347 struct btrfs_space_info *space_info,
5348 u64 num_bytes)
5349 {
5350 struct reserve_ticket *ticket;
5351 struct list_head *head;
5352 u64 used;
5353 enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_NO_FLUSH;
5354 bool check_overcommit = false;
5355
5356 spin_lock(&space_info->lock);
5357 head = &space_info->priority_tickets;
5358
5359 /*
5360 * If we are over our limit then we need to check and see if we can
5361 * overcommit, and if we can't then we just need to free up our space
5362 * and not satisfy any requests.
5363 */
5364 used = space_info->bytes_used + space_info->bytes_reserved +
5365 space_info->bytes_pinned + space_info->bytes_readonly +
5366 space_info->bytes_may_use;
5367 if (used - num_bytes >= space_info->total_bytes)
5368 check_overcommit = true;
5369 again:
5370 while (!list_empty(head) && num_bytes) {
5371 ticket = list_first_entry(head, struct reserve_ticket,
5372 list);
5373 /*
5374 * We use 0 bytes because this space is already reserved, so
5375 * adding the ticket space would be a double count.
5376 */
5377 if (check_overcommit &&
5378 !can_overcommit(fs_info->extent_root, space_info, 0,
5379 flush))
5380 break;
5381 if (num_bytes >= ticket->bytes) {
5382 list_del_init(&ticket->list);
5383 num_bytes -= ticket->bytes;
5384 ticket->bytes = 0;
5385 space_info->tickets_id++;
5386 wake_up(&ticket->wait);
5387 } else {
5388 ticket->bytes -= num_bytes;
5389 num_bytes = 0;
5390 }
5391 }
5392
5393 if (num_bytes && head == &space_info->priority_tickets) {
5394 head = &space_info->tickets;
5395 flush = BTRFS_RESERVE_FLUSH_ALL;
5396 goto again;
5397 }
5398 space_info->bytes_may_use -= num_bytes;
5399 trace_btrfs_space_reservation(fs_info, "space_info",
5400 space_info->flags, num_bytes, 0);
5401 spin_unlock(&space_info->lock);
5402 }
5403
5404 /*
5405 * This is for newly allocated space that isn't accounted in
5406 * space_info->bytes_may_use yet. So if we allocate a chunk or unpin an extent
5407 * we use this helper.
5408 */
5409 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
5410 struct btrfs_space_info *space_info,
5411 u64 num_bytes)
5412 {
5413 struct reserve_ticket *ticket;
5414 struct list_head *head = &space_info->priority_tickets;
5415
5416 again:
5417 while (!list_empty(head) && num_bytes) {
5418 ticket = list_first_entry(head, struct reserve_ticket,
5419 list);
5420 if (num_bytes >= ticket->bytes) {
5421 trace_btrfs_space_reservation(fs_info, "space_info",
5422 space_info->flags,
5423 ticket->bytes, 1);
5424 list_del_init(&ticket->list);
5425 num_bytes -= ticket->bytes;
5426 space_info->bytes_may_use += ticket->bytes;
5427 ticket->bytes = 0;
5428 space_info->tickets_id++;
5429 wake_up(&ticket->wait);
5430 } else {
5431 trace_btrfs_space_reservation(fs_info, "space_info",
5432 space_info->flags,
5433 num_bytes, 1);
5434 space_info->bytes_may_use += num_bytes;
5435 ticket->bytes -= num_bytes;
5436 num_bytes = 0;
5437 }
5438 }
5439
5440 if (num_bytes && head == &space_info->priority_tickets) {
5441 head = &space_info->tickets;
5442 goto again;
5443 }
5444 }
5445
5446 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
5447 struct btrfs_block_rsv *block_rsv,
5448 struct btrfs_block_rsv *dest, u64 num_bytes)
5449 {
5450 struct btrfs_space_info *space_info = block_rsv->space_info;
5451
5452 spin_lock(&block_rsv->lock);
5453 if (num_bytes == (u64)-1)
5454 num_bytes = block_rsv->size;
5455 block_rsv->size -= num_bytes;
5456 if (block_rsv->reserved >= block_rsv->size) {
5457 num_bytes = block_rsv->reserved - block_rsv->size;
5458 block_rsv->reserved = block_rsv->size;
5459 block_rsv->full = 1;
5460 } else {
5461 num_bytes = 0;
5462 }
5463 spin_unlock(&block_rsv->lock);
5464
5465 if (num_bytes > 0) {
5466 if (dest) {
5467 spin_lock(&dest->lock);
5468 if (!dest->full) {
5469 u64 bytes_to_add;
5470
5471 bytes_to_add = dest->size - dest->reserved;
5472 bytes_to_add = min(num_bytes, bytes_to_add);
5473 dest->reserved += bytes_to_add;
5474 if (dest->reserved >= dest->size)
5475 dest->full = 1;
5476 num_bytes -= bytes_to_add;
5477 }
5478 spin_unlock(&dest->lock);
5479 }
5480 if (num_bytes)
5481 space_info_add_old_bytes(fs_info, space_info,
5482 num_bytes);
5483 }
5484 }
5485
5486 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src,
5487 struct btrfs_block_rsv *dst, u64 num_bytes,
5488 int update_size)
5489 {
5490 int ret;
5491
5492 ret = block_rsv_use_bytes(src, num_bytes);
5493 if (ret)
5494 return ret;
5495
5496 block_rsv_add_bytes(dst, num_bytes, update_size);
5497 return 0;
5498 }
5499
5500 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
5501 {
5502 memset(rsv, 0, sizeof(*rsv));
5503 spin_lock_init(&rsv->lock);
5504 rsv->type = type;
5505 }
5506
5507 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
5508 unsigned short type)
5509 {
5510 struct btrfs_block_rsv *block_rsv;
5511 struct btrfs_fs_info *fs_info = root->fs_info;
5512
5513 block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
5514 if (!block_rsv)
5515 return NULL;
5516
5517 btrfs_init_block_rsv(block_rsv, type);
5518 block_rsv->space_info = __find_space_info(fs_info,
5519 BTRFS_BLOCK_GROUP_METADATA);
5520 return block_rsv;
5521 }
5522
5523 void btrfs_free_block_rsv(struct btrfs_root *root,
5524 struct btrfs_block_rsv *rsv)
5525 {
5526 if (!rsv)
5527 return;
5528 btrfs_block_rsv_release(root, rsv, (u64)-1);
5529 kfree(rsv);
5530 }
5531
5532 void __btrfs_free_block_rsv(struct btrfs_block_rsv *rsv)
5533 {
5534 kfree(rsv);
5535 }
5536
5537 int btrfs_block_rsv_add(struct btrfs_root *root,
5538 struct btrfs_block_rsv *block_rsv, u64 num_bytes,
5539 enum btrfs_reserve_flush_enum flush)
5540 {
5541 int ret;
5542
5543 if (num_bytes == 0)
5544 return 0;
5545
5546 ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5547 if (!ret) {
5548 block_rsv_add_bytes(block_rsv, num_bytes, 1);
5549 return 0;
5550 }
5551
5552 return ret;
5553 }
5554
5555 int btrfs_block_rsv_check(struct btrfs_root *root,
5556 struct btrfs_block_rsv *block_rsv, int min_factor)
5557 {
5558 u64 num_bytes = 0;
5559 int ret = -ENOSPC;
5560
5561 if (!block_rsv)
5562 return 0;
5563
5564 spin_lock(&block_rsv->lock);
5565 num_bytes = div_factor(block_rsv->size, min_factor);
5566 if (block_rsv->reserved >= num_bytes)
5567 ret = 0;
5568 spin_unlock(&block_rsv->lock);
5569
5570 return ret;
5571 }
5572
5573 int btrfs_block_rsv_refill(struct btrfs_root *root,
5574 struct btrfs_block_rsv *block_rsv, u64 min_reserved,
5575 enum btrfs_reserve_flush_enum flush)
5576 {
5577 u64 num_bytes = 0;
5578 int ret = -ENOSPC;
5579
5580 if (!block_rsv)
5581 return 0;
5582
5583 spin_lock(&block_rsv->lock);
5584 num_bytes = min_reserved;
5585 if (block_rsv->reserved >= num_bytes)
5586 ret = 0;
5587 else
5588 num_bytes -= block_rsv->reserved;
5589 spin_unlock(&block_rsv->lock);
5590
5591 if (!ret)
5592 return 0;
5593
5594 ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5595 if (!ret) {
5596 block_rsv_add_bytes(block_rsv, num_bytes, 0);
5597 return 0;
5598 }
5599
5600 return ret;
5601 }
5602
5603 void btrfs_block_rsv_release(struct btrfs_root *root,
5604 struct btrfs_block_rsv *block_rsv,
5605 u64 num_bytes)
5606 {
5607 struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5608 if (global_rsv == block_rsv ||
5609 block_rsv->space_info != global_rsv->space_info)
5610 global_rsv = NULL;
5611 block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
5612 num_bytes);
5613 }
5614
5615 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
5616 {
5617 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
5618 struct btrfs_space_info *sinfo = block_rsv->space_info;
5619 u64 num_bytes;
5620
5621 /*
5622 * The global block rsv is based on the size of the extent tree, the
5623 * checksum tree and the root tree. If the fs is empty we want to set
5624 * it to a minimal amount for safety.
5625 */
5626 num_bytes = btrfs_root_used(&fs_info->extent_root->root_item) +
5627 btrfs_root_used(&fs_info->csum_root->root_item) +
5628 btrfs_root_used(&fs_info->tree_root->root_item);
5629 num_bytes = max_t(u64, num_bytes, SZ_16M);
5630
5631 spin_lock(&sinfo->lock);
5632 spin_lock(&block_rsv->lock);
5633
5634 block_rsv->size = min_t(u64, num_bytes, SZ_512M);
5635
5636 if (block_rsv->reserved < block_rsv->size) {
5637 num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
5638 sinfo->bytes_reserved + sinfo->bytes_readonly +
5639 sinfo->bytes_may_use;
5640 if (sinfo->total_bytes > num_bytes) {
5641 num_bytes = sinfo->total_bytes - num_bytes;
5642 num_bytes = min(num_bytes,
5643 block_rsv->size - block_rsv->reserved);
5644 block_rsv->reserved += num_bytes;
5645 sinfo->bytes_may_use += num_bytes;
5646 trace_btrfs_space_reservation(fs_info, "space_info",
5647 sinfo->flags, num_bytes,
5648 1);
5649 }
5650 } else if (block_rsv->reserved > block_rsv->size) {
5651 num_bytes = block_rsv->reserved - block_rsv->size;
5652 sinfo->bytes_may_use -= num_bytes;
5653 trace_btrfs_space_reservation(fs_info, "space_info",
5654 sinfo->flags, num_bytes, 0);
5655 block_rsv->reserved = block_rsv->size;
5656 }
5657
5658 if (block_rsv->reserved == block_rsv->size)
5659 block_rsv->full = 1;
5660 else
5661 block_rsv->full = 0;
5662
5663 spin_unlock(&block_rsv->lock);
5664 spin_unlock(&sinfo->lock);
5665 }
5666
5667 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
5668 {
5669 struct btrfs_space_info *space_info;
5670
5671 space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
5672 fs_info->chunk_block_rsv.space_info = space_info;
5673
5674 space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5675 fs_info->global_block_rsv.space_info = space_info;
5676 fs_info->delalloc_block_rsv.space_info = space_info;
5677 fs_info->trans_block_rsv.space_info = space_info;
5678 fs_info->empty_block_rsv.space_info = space_info;
5679 fs_info->delayed_block_rsv.space_info = space_info;
5680
5681 fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
5682 fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
5683 fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
5684 fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
5685 if (fs_info->quota_root)
5686 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
5687 fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
5688
5689 update_global_block_rsv(fs_info);
5690 }
5691
5692 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
5693 {
5694 block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
5695 (u64)-1);
5696 WARN_ON(fs_info->delalloc_block_rsv.size > 0);
5697 WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
5698 WARN_ON(fs_info->trans_block_rsv.size > 0);
5699 WARN_ON(fs_info->trans_block_rsv.reserved > 0);
5700 WARN_ON(fs_info->chunk_block_rsv.size > 0);
5701 WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
5702 WARN_ON(fs_info->delayed_block_rsv.size > 0);
5703 WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
5704 }
5705
5706 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
5707 struct btrfs_root *root)
5708 {
5709 if (!trans->block_rsv)
5710 return;
5711
5712 if (!trans->bytes_reserved)
5713 return;
5714
5715 trace_btrfs_space_reservation(root->fs_info, "transaction",
5716 trans->transid, trans->bytes_reserved, 0);
5717 btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
5718 trans->bytes_reserved = 0;
5719 }
5720
5721 /*
5722 * To be called after all the new block groups attached to the transaction
5723 * handle have been created (btrfs_create_pending_block_groups()).
5724 */
5725 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
5726 {
5727 struct btrfs_fs_info *fs_info = trans->fs_info;
5728
5729 if (!trans->chunk_bytes_reserved)
5730 return;
5731
5732 WARN_ON_ONCE(!list_empty(&trans->new_bgs));
5733
5734 block_rsv_release_bytes(fs_info, &fs_info->chunk_block_rsv, NULL,
5735 trans->chunk_bytes_reserved);
5736 trans->chunk_bytes_reserved = 0;
5737 }
5738
5739 /* Can only return 0 or -ENOSPC */
5740 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
5741 struct inode *inode)
5742 {
5743 struct btrfs_root *root = BTRFS_I(inode)->root;
5744 /*
5745 * We always use trans->block_rsv here as we will have reserved space
5746 * for our orphan when starting the transaction, using get_block_rsv()
5747 * here will sometimes make us choose the wrong block rsv as we could be
5748 * doing a reloc inode for a non refcounted root.
5749 */
5750 struct btrfs_block_rsv *src_rsv = trans->block_rsv;
5751 struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
5752
5753 /*
5754 * We need to hold space in order to delete our orphan item once we've
5755 * added it, so this takes the reservation so we can release it later
5756 * when we are truly done with the orphan item.
5757 */
5758 u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5759 trace_btrfs_space_reservation(root->fs_info, "orphan",
5760 btrfs_ino(inode), num_bytes, 1);
5761 return btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes, 1);
5762 }
5763
5764 void btrfs_orphan_release_metadata(struct inode *inode)
5765 {
5766 struct btrfs_root *root = BTRFS_I(inode)->root;
5767 u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5768 trace_btrfs_space_reservation(root->fs_info, "orphan",
5769 btrfs_ino(inode), num_bytes, 0);
5770 btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
5771 }
5772
5773 /*
5774 * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
5775 * root: the root of the parent directory
5776 * rsv: block reservation
5777 * items: the number of items that we need do reservation
5778 * qgroup_reserved: used to return the reserved size in qgroup
5779 *
5780 * This function is used to reserve the space for snapshot/subvolume
5781 * creation and deletion. Those operations are different with the
5782 * common file/directory operations, they change two fs/file trees
5783 * and root tree, the number of items that the qgroup reserves is
5784 * different with the free space reservation. So we can not use
5785 * the space reservation mechanism in start_transaction().
5786 */
5787 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
5788 struct btrfs_block_rsv *rsv,
5789 int items,
5790 u64 *qgroup_reserved,
5791 bool use_global_rsv)
5792 {
5793 u64 num_bytes;
5794 int ret;
5795 struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5796
5797 if (test_bit(BTRFS_FS_QUOTA_ENABLED, &root->fs_info->flags)) {
5798 /* One for parent inode, two for dir entries */
5799 num_bytes = 3 * root->nodesize;
5800 ret = btrfs_qgroup_reserve_meta(root, num_bytes);
5801 if (ret)
5802 return ret;
5803 } else {
5804 num_bytes = 0;
5805 }
5806
5807 *qgroup_reserved = num_bytes;
5808
5809 num_bytes = btrfs_calc_trans_metadata_size(root, items);
5810 rsv->space_info = __find_space_info(root->fs_info,
5811 BTRFS_BLOCK_GROUP_METADATA);
5812 ret = btrfs_block_rsv_add(root, rsv, num_bytes,
5813 BTRFS_RESERVE_FLUSH_ALL);
5814
5815 if (ret == -ENOSPC && use_global_rsv)
5816 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes, 1);
5817
5818 if (ret && *qgroup_reserved)
5819 btrfs_qgroup_free_meta(root, *qgroup_reserved);
5820
5821 return ret;
5822 }
5823
5824 void btrfs_subvolume_release_metadata(struct btrfs_root *root,
5825 struct btrfs_block_rsv *rsv,
5826 u64 qgroup_reserved)
5827 {
5828 btrfs_block_rsv_release(root, rsv, (u64)-1);
5829 }
5830
5831 /**
5832 * drop_outstanding_extent - drop an outstanding extent
5833 * @inode: the inode we're dropping the extent for
5834 * @num_bytes: the number of bytes we're releasing.
5835 *
5836 * This is called when we are freeing up an outstanding extent, either called
5837 * after an error or after an extent is written. This will return the number of
5838 * reserved extents that need to be freed. This must be called with
5839 * BTRFS_I(inode)->lock held.
5840 */
5841 static unsigned drop_outstanding_extent(struct inode *inode, u64 num_bytes)
5842 {
5843 unsigned drop_inode_space = 0;
5844 unsigned dropped_extents = 0;
5845 unsigned num_extents = 0;
5846
5847 num_extents = (unsigned)div64_u64(num_bytes +
5848 BTRFS_MAX_EXTENT_SIZE - 1,
5849 BTRFS_MAX_EXTENT_SIZE);
5850 ASSERT(num_extents);
5851 ASSERT(BTRFS_I(inode)->outstanding_extents >= num_extents);
5852 BTRFS_I(inode)->outstanding_extents -= num_extents;
5853
5854 if (BTRFS_I(inode)->outstanding_extents == 0 &&
5855 test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5856 &BTRFS_I(inode)->runtime_flags))
5857 drop_inode_space = 1;
5858
5859 /*
5860 * If we have more or the same amount of outstanding extents than we have
5861 * reserved then we need to leave the reserved extents count alone.
5862 */
5863 if (BTRFS_I(inode)->outstanding_extents >=
5864 BTRFS_I(inode)->reserved_extents)
5865 return drop_inode_space;
5866
5867 dropped_extents = BTRFS_I(inode)->reserved_extents -
5868 BTRFS_I(inode)->outstanding_extents;
5869 BTRFS_I(inode)->reserved_extents -= dropped_extents;
5870 return dropped_extents + drop_inode_space;
5871 }
5872
5873 /**
5874 * calc_csum_metadata_size - return the amount of metadata space that must be
5875 * reserved/freed for the given bytes.
5876 * @inode: the inode we're manipulating
5877 * @num_bytes: the number of bytes in question
5878 * @reserve: 1 if we are reserving space, 0 if we are freeing space
5879 *
5880 * This adjusts the number of csum_bytes in the inode and then returns the
5881 * correct amount of metadata that must either be reserved or freed. We
5882 * calculate how many checksums we can fit into one leaf and then divide the
5883 * number of bytes that will need to be checksumed by this value to figure out
5884 * how many checksums will be required. If we are adding bytes then the number
5885 * may go up and we will return the number of additional bytes that must be
5886 * reserved. If it is going down we will return the number of bytes that must
5887 * be freed.
5888 *
5889 * This must be called with BTRFS_I(inode)->lock held.
5890 */
5891 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
5892 int reserve)
5893 {
5894 struct btrfs_root *root = BTRFS_I(inode)->root;
5895 u64 old_csums, num_csums;
5896
5897 if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
5898 BTRFS_I(inode)->csum_bytes == 0)
5899 return 0;
5900
5901 old_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5902 if (reserve)
5903 BTRFS_I(inode)->csum_bytes += num_bytes;
5904 else
5905 BTRFS_I(inode)->csum_bytes -= num_bytes;
5906 num_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5907
5908 /* No change, no need to reserve more */
5909 if (old_csums == num_csums)
5910 return 0;
5911
5912 if (reserve)
5913 return btrfs_calc_trans_metadata_size(root,
5914 num_csums - old_csums);
5915
5916 return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
5917 }
5918
5919 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
5920 {
5921 struct btrfs_root *root = BTRFS_I(inode)->root;
5922 struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
5923 u64 to_reserve = 0;
5924 u64 csum_bytes;
5925 unsigned nr_extents = 0;
5926 enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
5927 int ret = 0;
5928 bool delalloc_lock = true;
5929 u64 to_free = 0;
5930 unsigned dropped;
5931 bool release_extra = false;
5932
5933 /* If we are a free space inode we need to not flush since we will be in
5934 * the middle of a transaction commit. We also don't need the delalloc
5935 * mutex since we won't race with anybody. We need this mostly to make
5936 * lockdep shut its filthy mouth.
5937 *
5938 * If we have a transaction open (can happen if we call truncate_block
5939 * from truncate), then we need FLUSH_LIMIT so we don't deadlock.
5940 */
5941 if (btrfs_is_free_space_inode(inode)) {
5942 flush = BTRFS_RESERVE_NO_FLUSH;
5943 delalloc_lock = false;
5944 } else if (current->journal_info) {
5945 flush = BTRFS_RESERVE_FLUSH_LIMIT;
5946 }
5947
5948 if (flush != BTRFS_RESERVE_NO_FLUSH &&
5949 btrfs_transaction_in_commit(root->fs_info))
5950 schedule_timeout(1);
5951
5952 if (delalloc_lock)
5953 mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
5954
5955 num_bytes = ALIGN(num_bytes, root->sectorsize);
5956
5957 spin_lock(&BTRFS_I(inode)->lock);
5958 nr_extents = (unsigned)div64_u64(num_bytes +
5959 BTRFS_MAX_EXTENT_SIZE - 1,
5960 BTRFS_MAX_EXTENT_SIZE);
5961 BTRFS_I(inode)->outstanding_extents += nr_extents;
5962
5963 nr_extents = 0;
5964 if (BTRFS_I(inode)->outstanding_extents >
5965 BTRFS_I(inode)->reserved_extents)
5966 nr_extents += BTRFS_I(inode)->outstanding_extents -
5967 BTRFS_I(inode)->reserved_extents;
5968
5969 /* We always want to reserve a slot for updating the inode. */
5970 to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents + 1);
5971 to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
5972 csum_bytes = BTRFS_I(inode)->csum_bytes;
5973 spin_unlock(&BTRFS_I(inode)->lock);
5974
5975 if (test_bit(BTRFS_FS_QUOTA_ENABLED, &root->fs_info->flags)) {
5976 ret = btrfs_qgroup_reserve_meta(root,
5977 nr_extents * root->nodesize);
5978 if (ret)
5979 goto out_fail;
5980 }
5981
5982 ret = btrfs_block_rsv_add(root, block_rsv, to_reserve, flush);
5983 if (unlikely(ret)) {
5984 btrfs_qgroup_free_meta(root, nr_extents * root->nodesize);
5985 goto out_fail;
5986 }
5987
5988 spin_lock(&BTRFS_I(inode)->lock);
5989 if (test_and_set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5990 &BTRFS_I(inode)->runtime_flags)) {
5991 to_reserve -= btrfs_calc_trans_metadata_size(root, 1);
5992 release_extra = true;
5993 }
5994 BTRFS_I(inode)->reserved_extents += nr_extents;
5995 spin_unlock(&BTRFS_I(inode)->lock);
5996
5997 if (delalloc_lock)
5998 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5999
6000 if (to_reserve)
6001 trace_btrfs_space_reservation(root->fs_info, "delalloc",
6002 btrfs_ino(inode), to_reserve, 1);
6003 if (release_extra)
6004 btrfs_block_rsv_release(root, block_rsv,
6005 btrfs_calc_trans_metadata_size(root,
6006 1));
6007 return 0;
6008
6009 out_fail:
6010 spin_lock(&BTRFS_I(inode)->lock);
6011 dropped = drop_outstanding_extent(inode, num_bytes);
6012 /*
6013 * If the inodes csum_bytes is the same as the original
6014 * csum_bytes then we know we haven't raced with any free()ers
6015 * so we can just reduce our inodes csum bytes and carry on.
6016 */
6017 if (BTRFS_I(inode)->csum_bytes == csum_bytes) {
6018 calc_csum_metadata_size(inode, num_bytes, 0);
6019 } else {
6020 u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes;
6021 u64 bytes;
6022
6023 /*
6024 * This is tricky, but first we need to figure out how much we
6025 * freed from any free-ers that occurred during this
6026 * reservation, so we reset ->csum_bytes to the csum_bytes
6027 * before we dropped our lock, and then call the free for the
6028 * number of bytes that were freed while we were trying our
6029 * reservation.
6030 */
6031 bytes = csum_bytes - BTRFS_I(inode)->csum_bytes;
6032 BTRFS_I(inode)->csum_bytes = csum_bytes;
6033 to_free = calc_csum_metadata_size(inode, bytes, 0);
6034
6035
6036 /*
6037 * Now we need to see how much we would have freed had we not
6038 * been making this reservation and our ->csum_bytes were not
6039 * artificially inflated.
6040 */
6041 BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes;
6042 bytes = csum_bytes - orig_csum_bytes;
6043 bytes = calc_csum_metadata_size(inode, bytes, 0);
6044
6045 /*
6046 * Now reset ->csum_bytes to what it should be. If bytes is
6047 * more than to_free then we would have freed more space had we
6048 * not had an artificially high ->csum_bytes, so we need to free
6049 * the remainder. If bytes is the same or less then we don't
6050 * need to do anything, the other free-ers did the correct
6051 * thing.
6052 */
6053 BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes;
6054 if (bytes > to_free)
6055 to_free = bytes - to_free;
6056 else
6057 to_free = 0;
6058 }
6059 spin_unlock(&BTRFS_I(inode)->lock);
6060 if (dropped)
6061 to_free += btrfs_calc_trans_metadata_size(root, dropped);
6062
6063 if (to_free) {
6064 btrfs_block_rsv_release(root, block_rsv, to_free);
6065 trace_btrfs_space_reservation(root->fs_info, "delalloc",
6066 btrfs_ino(inode), to_free, 0);
6067 }
6068 if (delalloc_lock)
6069 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
6070 return ret;
6071 }
6072
6073 /**
6074 * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
6075 * @inode: the inode to release the reservation for
6076 * @num_bytes: the number of bytes we're releasing
6077 *
6078 * This will release the metadata reservation for an inode. This can be called
6079 * once we complete IO for a given set of bytes to release their metadata
6080 * reservations.
6081 */
6082 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
6083 {
6084 struct btrfs_root *root = BTRFS_I(inode)->root;
6085 u64 to_free = 0;
6086 unsigned dropped;
6087
6088 num_bytes = ALIGN(num_bytes, root->sectorsize);
6089 spin_lock(&BTRFS_I(inode)->lock);
6090 dropped = drop_outstanding_extent(inode, num_bytes);
6091
6092 if (num_bytes)
6093 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
6094 spin_unlock(&BTRFS_I(inode)->lock);
6095 if (dropped > 0)
6096 to_free += btrfs_calc_trans_metadata_size(root, dropped);
6097
6098 if (btrfs_is_testing(root->fs_info))
6099 return;
6100
6101 trace_btrfs_space_reservation(root->fs_info, "delalloc",
6102 btrfs_ino(inode), to_free, 0);
6103
6104 btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
6105 to_free);
6106 }
6107
6108 /**
6109 * btrfs_delalloc_reserve_space - reserve data and metadata space for
6110 * delalloc
6111 * @inode: inode we're writing to
6112 * @start: start range we are writing to
6113 * @len: how long the range we are writing to
6114 *
6115 * This will do the following things
6116 *
6117 * o reserve space in data space info for num bytes
6118 * and reserve precious corresponding qgroup space
6119 * (Done in check_data_free_space)
6120 *
6121 * o reserve space for metadata space, based on the number of outstanding
6122 * extents and how much csums will be needed
6123 * also reserve metadata space in a per root over-reserve method.
6124 * o add to the inodes->delalloc_bytes
6125 * o add it to the fs_info's delalloc inodes list.
6126 * (Above 3 all done in delalloc_reserve_metadata)
6127 *
6128 * Return 0 for success
6129 * Return <0 for error(-ENOSPC or -EQUOT)
6130 */
6131 int btrfs_delalloc_reserve_space(struct inode *inode, u64 start, u64 len)
6132 {
6133 int ret;
6134
6135 ret = btrfs_check_data_free_space(inode, start, len);
6136 if (ret < 0)
6137 return ret;
6138 ret = btrfs_delalloc_reserve_metadata(inode, len);
6139 if (ret < 0)
6140 btrfs_free_reserved_data_space(inode, start, len);
6141 return ret;
6142 }
6143
6144 /**
6145 * btrfs_delalloc_release_space - release data and metadata space for delalloc
6146 * @inode: inode we're releasing space for
6147 * @start: start position of the space already reserved
6148 * @len: the len of the space already reserved
6149 *
6150 * This must be matched with a call to btrfs_delalloc_reserve_space. This is
6151 * called in the case that we don't need the metadata AND data reservations
6152 * anymore. So if there is an error or we insert an inline extent.
6153 *
6154 * This function will release the metadata space that was not used and will
6155 * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
6156 * list if there are no delalloc bytes left.
6157 * Also it will handle the qgroup reserved space.
6158 */
6159 void btrfs_delalloc_release_space(struct inode *inode, u64 start, u64 len)
6160 {
6161 btrfs_delalloc_release_metadata(inode, len);
6162 btrfs_free_reserved_data_space(inode, start, len);
6163 }
6164
6165 static int update_block_group(struct btrfs_trans_handle *trans,
6166 struct btrfs_root *root, u64 bytenr,
6167 u64 num_bytes, int alloc)
6168 {
6169 struct btrfs_block_group_cache *cache = NULL;
6170 struct btrfs_fs_info *info = root->fs_info;
6171 u64 total = num_bytes;
6172 u64 old_val;
6173 u64 byte_in_group;
6174 int factor;
6175
6176 /* block accounting for super block */
6177 spin_lock(&info->delalloc_root_lock);
6178 old_val = btrfs_super_bytes_used(info->super_copy);
6179 if (alloc)
6180 old_val += num_bytes;
6181 else
6182 old_val -= num_bytes;
6183 btrfs_set_super_bytes_used(info->super_copy, old_val);
6184 spin_unlock(&info->delalloc_root_lock);
6185
6186 while (total) {
6187 cache = btrfs_lookup_block_group(info, bytenr);
6188 if (!cache)
6189 return -ENOENT;
6190 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
6191 BTRFS_BLOCK_GROUP_RAID1 |
6192 BTRFS_BLOCK_GROUP_RAID10))
6193 factor = 2;
6194 else
6195 factor = 1;
6196 /*
6197 * If this block group has free space cache written out, we
6198 * need to make sure to load it if we are removing space. This
6199 * is because we need the unpinning stage to actually add the
6200 * space back to the block group, otherwise we will leak space.
6201 */
6202 if (!alloc && cache->cached == BTRFS_CACHE_NO)
6203 cache_block_group(cache, 1);
6204
6205 byte_in_group = bytenr - cache->key.objectid;
6206 WARN_ON(byte_in_group > cache->key.offset);
6207
6208 spin_lock(&cache->space_info->lock);
6209 spin_lock(&cache->lock);
6210
6211 if (btrfs_test_opt(root->fs_info, SPACE_CACHE) &&
6212 cache->disk_cache_state < BTRFS_DC_CLEAR)
6213 cache->disk_cache_state = BTRFS_DC_CLEAR;
6214
6215 old_val = btrfs_block_group_used(&cache->item);
6216 num_bytes = min(total, cache->key.offset - byte_in_group);
6217 if (alloc) {
6218 old_val += num_bytes;
6219 btrfs_set_block_group_used(&cache->item, old_val);
6220 cache->reserved -= num_bytes;
6221 cache->space_info->bytes_reserved -= num_bytes;
6222 cache->space_info->bytes_used += num_bytes;
6223 cache->space_info->disk_used += num_bytes * factor;
6224 spin_unlock(&cache->lock);
6225 spin_unlock(&cache->space_info->lock);
6226 } else {
6227 old_val -= num_bytes;
6228 btrfs_set_block_group_used(&cache->item, old_val);
6229 cache->pinned += num_bytes;
6230 cache->space_info->bytes_pinned += num_bytes;
6231 cache->space_info->bytes_used -= num_bytes;
6232 cache->space_info->disk_used -= num_bytes * factor;
6233 spin_unlock(&cache->lock);
6234 spin_unlock(&cache->space_info->lock);
6235
6236 trace_btrfs_space_reservation(root->fs_info, "pinned",
6237 cache->space_info->flags,
6238 num_bytes, 1);
6239 set_extent_dirty(info->pinned_extents,
6240 bytenr, bytenr + num_bytes - 1,
6241 GFP_NOFS | __GFP_NOFAIL);
6242 }
6243
6244 spin_lock(&trans->transaction->dirty_bgs_lock);
6245 if (list_empty(&cache->dirty_list)) {
6246 list_add_tail(&cache->dirty_list,
6247 &trans->transaction->dirty_bgs);
6248 trans->transaction->num_dirty_bgs++;
6249 btrfs_get_block_group(cache);
6250 }
6251 spin_unlock(&trans->transaction->dirty_bgs_lock);
6252
6253 /*
6254 * No longer have used bytes in this block group, queue it for
6255 * deletion. We do this after adding the block group to the
6256 * dirty list to avoid races between cleaner kthread and space
6257 * cache writeout.
6258 */
6259 if (!alloc && old_val == 0) {
6260 spin_lock(&info->unused_bgs_lock);
6261 if (list_empty(&cache->bg_list)) {
6262 btrfs_get_block_group(cache);
6263 list_add_tail(&cache->bg_list,
6264 &info->unused_bgs);
6265 }
6266 spin_unlock(&info->unused_bgs_lock);
6267 }
6268
6269 btrfs_put_block_group(cache);
6270 total -= num_bytes;
6271 bytenr += num_bytes;
6272 }
6273 return 0;
6274 }
6275
6276 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
6277 {
6278 struct btrfs_block_group_cache *cache;
6279 u64 bytenr;
6280
6281 spin_lock(&root->fs_info->block_group_cache_lock);
6282 bytenr = root->fs_info->first_logical_byte;
6283 spin_unlock(&root->fs_info->block_group_cache_lock);
6284
6285 if (bytenr < (u64)-1)
6286 return bytenr;
6287
6288 cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
6289 if (!cache)
6290 return 0;
6291
6292 bytenr = cache->key.objectid;
6293 btrfs_put_block_group(cache);
6294
6295 return bytenr;
6296 }
6297
6298 static int pin_down_extent(struct btrfs_root *root,
6299 struct btrfs_block_group_cache *cache,
6300 u64 bytenr, u64 num_bytes, int reserved)
6301 {
6302 spin_lock(&cache->space_info->lock);
6303 spin_lock(&cache->lock);
6304 cache->pinned += num_bytes;
6305 cache->space_info->bytes_pinned += num_bytes;
6306 if (reserved) {
6307 cache->reserved -= num_bytes;
6308 cache->space_info->bytes_reserved -= num_bytes;
6309 }
6310 spin_unlock(&cache->lock);
6311 spin_unlock(&cache->space_info->lock);
6312
6313 trace_btrfs_space_reservation(root->fs_info, "pinned",
6314 cache->space_info->flags, num_bytes, 1);
6315 set_extent_dirty(root->fs_info->pinned_extents, bytenr,
6316 bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
6317 return 0;
6318 }
6319
6320 /*
6321 * this function must be called within transaction
6322 */
6323 int btrfs_pin_extent(struct btrfs_root *root,
6324 u64 bytenr, u64 num_bytes, int reserved)
6325 {
6326 struct btrfs_block_group_cache *cache;
6327
6328 cache = btrfs_lookup_block_group(root->fs_info, bytenr);
6329 BUG_ON(!cache); /* Logic error */
6330
6331 pin_down_extent(root, cache, bytenr, num_bytes, reserved);
6332
6333 btrfs_put_block_group(cache);
6334 return 0;
6335 }
6336
6337 /*
6338 * this function must be called within transaction
6339 */
6340 int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
6341 u64 bytenr, u64 num_bytes)
6342 {
6343 struct btrfs_block_group_cache *cache;
6344 int ret;
6345
6346 cache = btrfs_lookup_block_group(root->fs_info, bytenr);
6347 if (!cache)
6348 return -EINVAL;
6349
6350 /*
6351 * pull in the free space cache (if any) so that our pin
6352 * removes the free space from the cache. We have load_only set
6353 * to one because the slow code to read in the free extents does check
6354 * the pinned extents.
6355 */
6356 cache_block_group(cache, 1);
6357
6358 pin_down_extent(root, cache, bytenr, num_bytes, 0);
6359
6360 /* remove us from the free space cache (if we're there at all) */
6361 ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
6362 btrfs_put_block_group(cache);
6363 return ret;
6364 }
6365
6366 static int __exclude_logged_extent(struct btrfs_root *root, u64 start, u64 num_bytes)
6367 {
6368 int ret;
6369 struct btrfs_block_group_cache *block_group;
6370 struct btrfs_caching_control *caching_ctl;
6371
6372 block_group = btrfs_lookup_block_group(root->fs_info, start);
6373 if (!block_group)
6374 return -EINVAL;
6375
6376 cache_block_group(block_group, 0);
6377 caching_ctl = get_caching_control(block_group);
6378
6379 if (!caching_ctl) {
6380 /* Logic error */
6381 BUG_ON(!block_group_cache_done(block_group));
6382 ret = btrfs_remove_free_space(block_group, start, num_bytes);
6383 } else {
6384 mutex_lock(&caching_ctl->mutex);
6385
6386 if (start >= caching_ctl->progress) {
6387 ret = add_excluded_extent(root, start, num_bytes);
6388 } else if (start + num_bytes <= caching_ctl->progress) {
6389 ret = btrfs_remove_free_space(block_group,
6390 start, num_bytes);
6391 } else {
6392 num_bytes = caching_ctl->progress - start;
6393 ret = btrfs_remove_free_space(block_group,
6394 start, num_bytes);
6395 if (ret)
6396 goto out_lock;
6397
6398 num_bytes = (start + num_bytes) -
6399 caching_ctl->progress;
6400 start = caching_ctl->progress;
6401 ret = add_excluded_extent(root, start, num_bytes);
6402 }
6403 out_lock:
6404 mutex_unlock(&caching_ctl->mutex);
6405 put_caching_control(caching_ctl);
6406 }
6407 btrfs_put_block_group(block_group);
6408 return ret;
6409 }
6410
6411 int btrfs_exclude_logged_extents(struct btrfs_root *log,
6412 struct extent_buffer *eb)
6413 {
6414 struct btrfs_file_extent_item *item;
6415 struct btrfs_key key;
6416 int found_type;
6417 int i;
6418
6419 if (!btrfs_fs_incompat(log->fs_info, MIXED_GROUPS))
6420 return 0;
6421
6422 for (i = 0; i < btrfs_header_nritems(eb); i++) {
6423 btrfs_item_key_to_cpu(eb, &key, i);
6424 if (key.type != BTRFS_EXTENT_DATA_KEY)
6425 continue;
6426 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
6427 found_type = btrfs_file_extent_type(eb, item);
6428 if (found_type == BTRFS_FILE_EXTENT_INLINE)
6429 continue;
6430 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
6431 continue;
6432 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
6433 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
6434 __exclude_logged_extent(log, key.objectid, key.offset);
6435 }
6436
6437 return 0;
6438 }
6439
6440 static void
6441 btrfs_inc_block_group_reservations(struct btrfs_block_group_cache *bg)
6442 {
6443 atomic_inc(&bg->reservations);
6444 }
6445
6446 void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
6447 const u64 start)
6448 {
6449 struct btrfs_block_group_cache *bg;
6450
6451 bg = btrfs_lookup_block_group(fs_info, start);
6452 ASSERT(bg);
6453 if (atomic_dec_and_test(&bg->reservations))
6454 wake_up_atomic_t(&bg->reservations);
6455 btrfs_put_block_group(bg);
6456 }
6457
6458 static int btrfs_wait_bg_reservations_atomic_t(atomic_t *a)
6459 {
6460 schedule();
6461 return 0;
6462 }
6463
6464 void btrfs_wait_block_group_reservations(struct btrfs_block_group_cache *bg)
6465 {
6466 struct btrfs_space_info *space_info = bg->space_info;
6467
6468 ASSERT(bg->ro);
6469
6470 if (!(bg->flags & BTRFS_BLOCK_GROUP_DATA))
6471 return;
6472
6473 /*
6474 * Our block group is read only but before we set it to read only,
6475 * some task might have had allocated an extent from it already, but it
6476 * has not yet created a respective ordered extent (and added it to a
6477 * root's list of ordered extents).
6478 * Therefore wait for any task currently allocating extents, since the
6479 * block group's reservations counter is incremented while a read lock
6480 * on the groups' semaphore is held and decremented after releasing
6481 * the read access on that semaphore and creating the ordered extent.
6482 */
6483 down_write(&space_info->groups_sem);
6484 up_write(&space_info->groups_sem);
6485
6486 wait_on_atomic_t(&bg->reservations,
6487 btrfs_wait_bg_reservations_atomic_t,
6488 TASK_UNINTERRUPTIBLE);
6489 }
6490
6491 /**
6492 * btrfs_add_reserved_bytes - update the block_group and space info counters
6493 * @cache: The cache we are manipulating
6494 * @ram_bytes: The number of bytes of file content, and will be same to
6495 * @num_bytes except for the compress path.
6496 * @num_bytes: The number of bytes in question
6497 * @delalloc: The blocks are allocated for the delalloc write
6498 *
6499 * This is called by the allocator when it reserves space. Metadata
6500 * reservations should be called with RESERVE_ALLOC so we do the proper
6501 * ENOSPC accounting. For data we handle the reservation through clearing the
6502 * delalloc bits in the io_tree. We have to do this since we could end up
6503 * allocating less disk space for the amount of data we have reserved in the
6504 * case of compression.
6505 *
6506 * If this is a reservation and the block group has become read only we cannot
6507 * make the reservation and return -EAGAIN, otherwise this function always
6508 * succeeds.
6509 */
6510 static int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
6511 u64 ram_bytes, u64 num_bytes, int delalloc)
6512 {
6513 struct btrfs_space_info *space_info = cache->space_info;
6514 int ret = 0;
6515
6516 spin_lock(&space_info->lock);
6517 spin_lock(&cache->lock);
6518 if (cache->ro) {
6519 ret = -EAGAIN;
6520 } else {
6521 cache->reserved += num_bytes;
6522 space_info->bytes_reserved += num_bytes;
6523
6524 trace_btrfs_space_reservation(cache->fs_info,
6525 "space_info", space_info->flags,
6526 ram_bytes, 0);
6527 space_info->bytes_may_use -= ram_bytes;
6528 if (delalloc)
6529 cache->delalloc_bytes += num_bytes;
6530 }
6531 spin_unlock(&cache->lock);
6532 spin_unlock(&space_info->lock);
6533 return ret;
6534 }
6535
6536 /**
6537 * btrfs_free_reserved_bytes - update the block_group and space info counters
6538 * @cache: The cache we are manipulating
6539 * @num_bytes: The number of bytes in question
6540 * @delalloc: The blocks are allocated for the delalloc write
6541 *
6542 * This is called by somebody who is freeing space that was never actually used
6543 * on disk. For example if you reserve some space for a new leaf in transaction
6544 * A and before transaction A commits you free that leaf, you call this with
6545 * reserve set to 0 in order to clear the reservation.
6546 */
6547
6548 static int btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
6549 u64 num_bytes, int delalloc)
6550 {
6551 struct btrfs_space_info *space_info = cache->space_info;
6552 int ret = 0;
6553
6554 spin_lock(&space_info->lock);
6555 spin_lock(&cache->lock);
6556 if (cache->ro)
6557 space_info->bytes_readonly += num_bytes;
6558 cache->reserved -= num_bytes;
6559 space_info->bytes_reserved -= num_bytes;
6560
6561 if (delalloc)
6562 cache->delalloc_bytes -= num_bytes;
6563 spin_unlock(&cache->lock);
6564 spin_unlock(&space_info->lock);
6565 return ret;
6566 }
6567 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
6568 struct btrfs_root *root)
6569 {
6570 struct btrfs_fs_info *fs_info = root->fs_info;
6571 struct btrfs_caching_control *next;
6572 struct btrfs_caching_control *caching_ctl;
6573 struct btrfs_block_group_cache *cache;
6574
6575 down_write(&fs_info->commit_root_sem);
6576
6577 list_for_each_entry_safe(caching_ctl, next,
6578 &fs_info->caching_block_groups, list) {
6579 cache = caching_ctl->block_group;
6580 if (block_group_cache_done(cache)) {
6581 cache->last_byte_to_unpin = (u64)-1;
6582 list_del_init(&caching_ctl->list);
6583 put_caching_control(caching_ctl);
6584 } else {
6585 cache->last_byte_to_unpin = caching_ctl->progress;
6586 }
6587 }
6588
6589 if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6590 fs_info->pinned_extents = &fs_info->freed_extents[1];
6591 else
6592 fs_info->pinned_extents = &fs_info->freed_extents[0];
6593
6594 up_write(&fs_info->commit_root_sem);
6595
6596 update_global_block_rsv(fs_info);
6597 }
6598
6599 /*
6600 * Returns the free cluster for the given space info and sets empty_cluster to
6601 * what it should be based on the mount options.
6602 */
6603 static struct btrfs_free_cluster *
6604 fetch_cluster_info(struct btrfs_root *root, struct btrfs_space_info *space_info,
6605 u64 *empty_cluster)
6606 {
6607 struct btrfs_free_cluster *ret = NULL;
6608 bool ssd = btrfs_test_opt(root->fs_info, SSD);
6609
6610 *empty_cluster = 0;
6611 if (btrfs_mixed_space_info(space_info))
6612 return ret;
6613
6614 if (ssd)
6615 *empty_cluster = SZ_2M;
6616 if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
6617 ret = &root->fs_info->meta_alloc_cluster;
6618 if (!ssd)
6619 *empty_cluster = SZ_64K;
6620 } else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) && ssd) {
6621 ret = &root->fs_info->data_alloc_cluster;
6622 }
6623
6624 return ret;
6625 }
6626
6627 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end,
6628 const bool return_free_space)
6629 {
6630 struct btrfs_fs_info *fs_info = root->fs_info;
6631 struct btrfs_block_group_cache *cache = NULL;
6632 struct btrfs_space_info *space_info;
6633 struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
6634 struct btrfs_free_cluster *cluster = NULL;
6635 u64 len;
6636 u64 total_unpinned = 0;
6637 u64 empty_cluster = 0;
6638 bool readonly;
6639
6640 while (start <= end) {
6641 readonly = false;
6642 if (!cache ||
6643 start >= cache->key.objectid + cache->key.offset) {
6644 if (cache)
6645 btrfs_put_block_group(cache);
6646 total_unpinned = 0;
6647 cache = btrfs_lookup_block_group(fs_info, start);
6648 BUG_ON(!cache); /* Logic error */
6649
6650 cluster = fetch_cluster_info(root,
6651 cache->space_info,
6652 &empty_cluster);
6653 empty_cluster <<= 1;
6654 }
6655
6656 len = cache->key.objectid + cache->key.offset - start;
6657 len = min(len, end + 1 - start);
6658
6659 if (start < cache->last_byte_to_unpin) {
6660 len = min(len, cache->last_byte_to_unpin - start);
6661 if (return_free_space)
6662 btrfs_add_free_space(cache, start, len);
6663 }
6664
6665 start += len;
6666 total_unpinned += len;
6667 space_info = cache->space_info;
6668
6669 /*
6670 * If this space cluster has been marked as fragmented and we've
6671 * unpinned enough in this block group to potentially allow a
6672 * cluster to be created inside of it go ahead and clear the
6673 * fragmented check.
6674 */
6675 if (cluster && cluster->fragmented &&
6676 total_unpinned > empty_cluster) {
6677 spin_lock(&cluster->lock);
6678 cluster->fragmented = 0;
6679 spin_unlock(&cluster->lock);
6680 }
6681
6682 spin_lock(&space_info->lock);
6683 spin_lock(&cache->lock);
6684 cache->pinned -= len;
6685 space_info->bytes_pinned -= len;
6686
6687 trace_btrfs_space_reservation(fs_info, "pinned",
6688 space_info->flags, len, 0);
6689 space_info->max_extent_size = 0;
6690 percpu_counter_add(&space_info->total_bytes_pinned, -len);
6691 if (cache->ro) {
6692 space_info->bytes_readonly += len;
6693 readonly = true;
6694 }
6695 spin_unlock(&cache->lock);
6696 if (!readonly && return_free_space &&
6697 global_rsv->space_info == space_info) {
6698 u64 to_add = len;
6699 WARN_ON(!return_free_space);
6700 spin_lock(&global_rsv->lock);
6701 if (!global_rsv->full) {
6702 to_add = min(len, global_rsv->size -
6703 global_rsv->reserved);
6704 global_rsv->reserved += to_add;
6705 space_info->bytes_may_use += to_add;
6706 if (global_rsv->reserved >= global_rsv->size)
6707 global_rsv->full = 1;
6708 trace_btrfs_space_reservation(fs_info,
6709 "space_info",
6710 space_info->flags,
6711 to_add, 1);
6712 len -= to_add;
6713 }
6714 spin_unlock(&global_rsv->lock);
6715 /* Add to any tickets we may have */
6716 if (len)
6717 space_info_add_new_bytes(fs_info, space_info,
6718 len);
6719 }
6720 spin_unlock(&space_info->lock);
6721 }
6722
6723 if (cache)
6724 btrfs_put_block_group(cache);
6725 return 0;
6726 }
6727
6728 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
6729 struct btrfs_root *root)
6730 {
6731 struct btrfs_fs_info *fs_info = root->fs_info;
6732 struct btrfs_block_group_cache *block_group, *tmp;
6733 struct list_head *deleted_bgs;
6734 struct extent_io_tree *unpin;
6735 u64 start;
6736 u64 end;
6737 int ret;
6738
6739 if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6740 unpin = &fs_info->freed_extents[1];
6741 else
6742 unpin = &fs_info->freed_extents[0];
6743
6744 while (!trans->aborted) {
6745 mutex_lock(&fs_info->unused_bg_unpin_mutex);
6746 ret = find_first_extent_bit(unpin, 0, &start, &end,
6747 EXTENT_DIRTY, NULL);
6748 if (ret) {
6749 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6750 break;
6751 }
6752
6753 if (btrfs_test_opt(root->fs_info, DISCARD))
6754 ret = btrfs_discard_extent(root, start,
6755 end + 1 - start, NULL);
6756
6757 clear_extent_dirty(unpin, start, end);
6758 unpin_extent_range(root, start, end, true);
6759 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6760 cond_resched();
6761 }
6762
6763 /*
6764 * Transaction is finished. We don't need the lock anymore. We
6765 * do need to clean up the block groups in case of a transaction
6766 * abort.
6767 */
6768 deleted_bgs = &trans->transaction->deleted_bgs;
6769 list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
6770 u64 trimmed = 0;
6771
6772 ret = -EROFS;
6773 if (!trans->aborted)
6774 ret = btrfs_discard_extent(root,
6775 block_group->key.objectid,
6776 block_group->key.offset,
6777 &trimmed);
6778
6779 list_del_init(&block_group->bg_list);
6780 btrfs_put_block_group_trimming(block_group);
6781 btrfs_put_block_group(block_group);
6782
6783 if (ret) {
6784 const char *errstr = btrfs_decode_error(ret);
6785 btrfs_warn(fs_info,
6786 "Discard failed while removing blockgroup: errno=%d %s\n",
6787 ret, errstr);
6788 }
6789 }
6790
6791 return 0;
6792 }
6793
6794 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, u64 num_bytes,
6795 u64 owner, u64 root_objectid)
6796 {
6797 struct btrfs_space_info *space_info;
6798 u64 flags;
6799
6800 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6801 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
6802 flags = BTRFS_BLOCK_GROUP_SYSTEM;
6803 else
6804 flags = BTRFS_BLOCK_GROUP_METADATA;
6805 } else {
6806 flags = BTRFS_BLOCK_GROUP_DATA;
6807 }
6808
6809 space_info = __find_space_info(fs_info, flags);
6810 BUG_ON(!space_info); /* Logic bug */
6811 percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
6812 }
6813
6814
6815 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
6816 struct btrfs_root *root,
6817 struct btrfs_delayed_ref_node *node, u64 parent,
6818 u64 root_objectid, u64 owner_objectid,
6819 u64 owner_offset, int refs_to_drop,
6820 struct btrfs_delayed_extent_op *extent_op)
6821 {
6822 struct btrfs_key key;
6823 struct btrfs_path *path;
6824 struct btrfs_fs_info *info = root->fs_info;
6825 struct btrfs_root *extent_root = info->extent_root;
6826 struct extent_buffer *leaf;
6827 struct btrfs_extent_item *ei;
6828 struct btrfs_extent_inline_ref *iref;
6829 int ret;
6830 int is_data;
6831 int extent_slot = 0;
6832 int found_extent = 0;
6833 int num_to_del = 1;
6834 u32 item_size;
6835 u64 refs;
6836 u64 bytenr = node->bytenr;
6837 u64 num_bytes = node->num_bytes;
6838 int last_ref = 0;
6839 bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6840 SKINNY_METADATA);
6841
6842 path = btrfs_alloc_path();
6843 if (!path)
6844 return -ENOMEM;
6845
6846 path->reada = READA_FORWARD;
6847 path->leave_spinning = 1;
6848
6849 is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
6850 BUG_ON(!is_data && refs_to_drop != 1);
6851
6852 if (is_data)
6853 skinny_metadata = 0;
6854
6855 ret = lookup_extent_backref(trans, extent_root, path, &iref,
6856 bytenr, num_bytes, parent,
6857 root_objectid, owner_objectid,
6858 owner_offset);
6859 if (ret == 0) {
6860 extent_slot = path->slots[0];
6861 while (extent_slot >= 0) {
6862 btrfs_item_key_to_cpu(path->nodes[0], &key,
6863 extent_slot);
6864 if (key.objectid != bytenr)
6865 break;
6866 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
6867 key.offset == num_bytes) {
6868 found_extent = 1;
6869 break;
6870 }
6871 if (key.type == BTRFS_METADATA_ITEM_KEY &&
6872 key.offset == owner_objectid) {
6873 found_extent = 1;
6874 break;
6875 }
6876 if (path->slots[0] - extent_slot > 5)
6877 break;
6878 extent_slot--;
6879 }
6880 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6881 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
6882 if (found_extent && item_size < sizeof(*ei))
6883 found_extent = 0;
6884 #endif
6885 if (!found_extent) {
6886 BUG_ON(iref);
6887 ret = remove_extent_backref(trans, extent_root, path,
6888 NULL, refs_to_drop,
6889 is_data, &last_ref);
6890 if (ret) {
6891 btrfs_abort_transaction(trans, ret);
6892 goto out;
6893 }
6894 btrfs_release_path(path);
6895 path->leave_spinning = 1;
6896
6897 key.objectid = bytenr;
6898 key.type = BTRFS_EXTENT_ITEM_KEY;
6899 key.offset = num_bytes;
6900
6901 if (!is_data && skinny_metadata) {
6902 key.type = BTRFS_METADATA_ITEM_KEY;
6903 key.offset = owner_objectid;
6904 }
6905
6906 ret = btrfs_search_slot(trans, extent_root,
6907 &key, path, -1, 1);
6908 if (ret > 0 && skinny_metadata && path->slots[0]) {
6909 /*
6910 * Couldn't find our skinny metadata item,
6911 * see if we have ye olde extent item.
6912 */
6913 path->slots[0]--;
6914 btrfs_item_key_to_cpu(path->nodes[0], &key,
6915 path->slots[0]);
6916 if (key.objectid == bytenr &&
6917 key.type == BTRFS_EXTENT_ITEM_KEY &&
6918 key.offset == num_bytes)
6919 ret = 0;
6920 }
6921
6922 if (ret > 0 && skinny_metadata) {
6923 skinny_metadata = false;
6924 key.objectid = bytenr;
6925 key.type = BTRFS_EXTENT_ITEM_KEY;
6926 key.offset = num_bytes;
6927 btrfs_release_path(path);
6928 ret = btrfs_search_slot(trans, extent_root,
6929 &key, path, -1, 1);
6930 }
6931
6932 if (ret) {
6933 btrfs_err(info,
6934 "umm, got %d back from search, was looking for %llu",
6935 ret, bytenr);
6936 if (ret > 0)
6937 btrfs_print_leaf(extent_root,
6938 path->nodes[0]);
6939 }
6940 if (ret < 0) {
6941 btrfs_abort_transaction(trans, ret);
6942 goto out;
6943 }
6944 extent_slot = path->slots[0];
6945 }
6946 } else if (WARN_ON(ret == -ENOENT)) {
6947 btrfs_print_leaf(extent_root, path->nodes[0]);
6948 btrfs_err(info,
6949 "unable to find ref byte nr %llu parent %llu root %llu owner %llu offset %llu",
6950 bytenr, parent, root_objectid, owner_objectid,
6951 owner_offset);
6952 btrfs_abort_transaction(trans, ret);
6953 goto out;
6954 } else {
6955 btrfs_abort_transaction(trans, ret);
6956 goto out;
6957 }
6958
6959 leaf = path->nodes[0];
6960 item_size = btrfs_item_size_nr(leaf, extent_slot);
6961 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6962 if (item_size < sizeof(*ei)) {
6963 BUG_ON(found_extent || extent_slot != path->slots[0]);
6964 ret = convert_extent_item_v0(trans, extent_root, path,
6965 owner_objectid, 0);
6966 if (ret < 0) {
6967 btrfs_abort_transaction(trans, ret);
6968 goto out;
6969 }
6970
6971 btrfs_release_path(path);
6972 path->leave_spinning = 1;
6973
6974 key.objectid = bytenr;
6975 key.type = BTRFS_EXTENT_ITEM_KEY;
6976 key.offset = num_bytes;
6977
6978 ret = btrfs_search_slot(trans, extent_root, &key, path,
6979 -1, 1);
6980 if (ret) {
6981 btrfs_err(info,
6982 "umm, got %d back from search, was looking for %llu",
6983 ret, bytenr);
6984 btrfs_print_leaf(extent_root, path->nodes[0]);
6985 }
6986 if (ret < 0) {
6987 btrfs_abort_transaction(trans, ret);
6988 goto out;
6989 }
6990
6991 extent_slot = path->slots[0];
6992 leaf = path->nodes[0];
6993 item_size = btrfs_item_size_nr(leaf, extent_slot);
6994 }
6995 #endif
6996 BUG_ON(item_size < sizeof(*ei));
6997 ei = btrfs_item_ptr(leaf, extent_slot,
6998 struct btrfs_extent_item);
6999 if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
7000 key.type == BTRFS_EXTENT_ITEM_KEY) {
7001 struct btrfs_tree_block_info *bi;
7002 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
7003 bi = (struct btrfs_tree_block_info *)(ei + 1);
7004 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
7005 }
7006
7007 refs = btrfs_extent_refs(leaf, ei);
7008 if (refs < refs_to_drop) {
7009 btrfs_err(info,
7010 "trying to drop %d refs but we only have %Lu for bytenr %Lu",
7011 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_fs_info *fs_info,
7908 struct btrfs_space_info *info, u64 bytes,
7909 int dump_block_groups)
7910 {
7911 struct btrfs_block_group_cache *cache;
7912 int index = 0;
7913
7914 spin_lock(&info->lock);
7915 btrfs_info(fs_info, "space_info %llu has %llu free, is %sfull",
7916 info->flags,
7917 info->total_bytes - info->bytes_used - info->bytes_pinned -
7918 info->bytes_reserved - info->bytes_readonly -
7919 info->bytes_may_use, (info->full) ? "" : "not ");
7920 btrfs_info(fs_info,
7921 "space_info total=%llu, used=%llu, pinned=%llu, reserved=%llu, may_use=%llu, readonly=%llu",
7922 info->total_bytes, info->bytes_used, info->bytes_pinned,
7923 info->bytes_reserved, info->bytes_may_use,
7924 info->bytes_readonly);
7925 spin_unlock(&info->lock);
7926
7927 if (!dump_block_groups)
7928 return;
7929
7930 down_read(&info->groups_sem);
7931 again:
7932 list_for_each_entry(cache, &info->block_groups[index], list) {
7933 spin_lock(&cache->lock);
7934 btrfs_info(fs_info,
7935 "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %s",
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 struct btrfs_fs_info *fs_info = root->fs_info;
7953 bool final_tried = num_bytes == min_alloc_size;
7954 u64 flags;
7955 int ret;
7956
7957 flags = btrfs_get_alloc_profile(root, is_data);
7958 again:
7959 WARN_ON(num_bytes < root->sectorsize);
7960 ret = find_free_extent(root, ram_bytes, num_bytes, empty_size,
7961 hint_byte, ins, flags, delalloc);
7962 if (!ret && !is_data) {
7963 btrfs_dec_block_group_reservations(fs_info, 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(fs_info, ENOSPC_DEBUG)) {
7974 struct btrfs_space_info *sinfo;
7975
7976 sinfo = __find_space_info(fs_info, flags);
7977 btrfs_err(root->fs_info,
7978 "allocation failed flags %llu, wanted %llu",
7979 flags, num_bytes);
7980 if (sinfo)
7981 dump_space_info(fs_info, sinfo, num_bytes, 1);
7982 }
7983 }
7984
7985 return ret;
7986 }
7987
7988 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
7989 u64 start, u64 len,
7990 int pin, int delalloc)
7991 {
7992 struct btrfs_block_group_cache *cache;
7993 int ret = 0;
7994
7995 cache = btrfs_lookup_block_group(root->fs_info, start);
7996 if (!cache) {
7997 btrfs_err(root->fs_info, "Unable to find block group for %llu",
7998 start);
7999 return -ENOSPC;
8000 }
8001
8002 if (pin)
8003 pin_down_extent(root, cache, start, len, 1);
8004 else {
8005 if (btrfs_test_opt(root->fs_info, DISCARD))
8006 ret = btrfs_discard_extent(root, start, len, NULL);
8007 btrfs_add_free_space(cache, start, len);
8008 btrfs_free_reserved_bytes(cache, len, delalloc);
8009 trace_btrfs_reserved_extent_free(root, start, len);
8010 }
8011
8012 btrfs_put_block_group(cache);
8013 return ret;
8014 }
8015
8016 int btrfs_free_reserved_extent(struct btrfs_root *root,
8017 u64 start, u64 len, int delalloc)
8018 {
8019 return __btrfs_free_reserved_extent(root, start, len, 0, delalloc);
8020 }
8021
8022 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
8023 u64 start, u64 len)
8024 {
8025 return __btrfs_free_reserved_extent(root, start, len, 1, 0);
8026 }
8027
8028 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8029 struct btrfs_root *root,
8030 u64 parent, u64 root_objectid,
8031 u64 flags, u64 owner, u64 offset,
8032 struct btrfs_key *ins, int ref_mod)
8033 {
8034 int ret;
8035 struct btrfs_fs_info *fs_info = root->fs_info;
8036 struct btrfs_extent_item *extent_item;
8037 struct btrfs_extent_inline_ref *iref;
8038 struct btrfs_path *path;
8039 struct extent_buffer *leaf;
8040 int type;
8041 u32 size;
8042
8043 if (parent > 0)
8044 type = BTRFS_SHARED_DATA_REF_KEY;
8045 else
8046 type = BTRFS_EXTENT_DATA_REF_KEY;
8047
8048 size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
8049
8050 path = btrfs_alloc_path();
8051 if (!path)
8052 return -ENOMEM;
8053
8054 path->leave_spinning = 1;
8055 ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
8056 ins, size);
8057 if (ret) {
8058 btrfs_free_path(path);
8059 return ret;
8060 }
8061
8062 leaf = path->nodes[0];
8063 extent_item = btrfs_item_ptr(leaf, path->slots[0],
8064 struct btrfs_extent_item);
8065 btrfs_set_extent_refs(leaf, extent_item, ref_mod);
8066 btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8067 btrfs_set_extent_flags(leaf, extent_item,
8068 flags | BTRFS_EXTENT_FLAG_DATA);
8069
8070 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8071 btrfs_set_extent_inline_ref_type(leaf, iref, type);
8072 if (parent > 0) {
8073 struct btrfs_shared_data_ref *ref;
8074 ref = (struct btrfs_shared_data_ref *)(iref + 1);
8075 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
8076 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
8077 } else {
8078 struct btrfs_extent_data_ref *ref;
8079 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
8080 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
8081 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
8082 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
8083 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
8084 }
8085
8086 btrfs_mark_buffer_dirty(path->nodes[0]);
8087 btrfs_free_path(path);
8088
8089 ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
8090 ins->offset);
8091 if (ret)
8092 return ret;
8093
8094 ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
8095 if (ret) { /* -ENOENT, logic error */
8096 btrfs_err(fs_info, "update block group failed for %llu %llu",
8097 ins->objectid, ins->offset);
8098 BUG();
8099 }
8100 trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
8101 return ret;
8102 }
8103
8104 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
8105 struct btrfs_root *root,
8106 u64 parent, u64 root_objectid,
8107 u64 flags, struct btrfs_disk_key *key,
8108 int level, struct btrfs_key *ins)
8109 {
8110 int ret;
8111 struct btrfs_fs_info *fs_info = root->fs_info;
8112 struct btrfs_extent_item *extent_item;
8113 struct btrfs_tree_block_info *block_info;
8114 struct btrfs_extent_inline_ref *iref;
8115 struct btrfs_path *path;
8116 struct extent_buffer *leaf;
8117 u32 size = sizeof(*extent_item) + sizeof(*iref);
8118 u64 num_bytes = ins->offset;
8119 bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
8120 SKINNY_METADATA);
8121
8122 if (!skinny_metadata)
8123 size += sizeof(*block_info);
8124
8125 path = btrfs_alloc_path();
8126 if (!path) {
8127 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
8128 root->nodesize);
8129 return -ENOMEM;
8130 }
8131
8132 path->leave_spinning = 1;
8133 ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
8134 ins, size);
8135 if (ret) {
8136 btrfs_free_path(path);
8137 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
8138 root->nodesize);
8139 return ret;
8140 }
8141
8142 leaf = path->nodes[0];
8143 extent_item = btrfs_item_ptr(leaf, path->slots[0],
8144 struct btrfs_extent_item);
8145 btrfs_set_extent_refs(leaf, extent_item, 1);
8146 btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8147 btrfs_set_extent_flags(leaf, extent_item,
8148 flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
8149
8150 if (skinny_metadata) {
8151 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8152 num_bytes = root->nodesize;
8153 } else {
8154 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
8155 btrfs_set_tree_block_key(leaf, block_info, key);
8156 btrfs_set_tree_block_level(leaf, block_info, level);
8157 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
8158 }
8159
8160 if (parent > 0) {
8161 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
8162 btrfs_set_extent_inline_ref_type(leaf, iref,
8163 BTRFS_SHARED_BLOCK_REF_KEY);
8164 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
8165 } else {
8166 btrfs_set_extent_inline_ref_type(leaf, iref,
8167 BTRFS_TREE_BLOCK_REF_KEY);
8168 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
8169 }
8170
8171 btrfs_mark_buffer_dirty(leaf);
8172 btrfs_free_path(path);
8173
8174 ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
8175 num_bytes);
8176 if (ret)
8177 return ret;
8178
8179 ret = update_block_group(trans, root, ins->objectid, root->nodesize,
8180 1);
8181 if (ret) { /* -ENOENT, logic error */
8182 btrfs_err(fs_info, "update block group failed for %llu %llu",
8183 ins->objectid, ins->offset);
8184 BUG();
8185 }
8186
8187 trace_btrfs_reserved_extent_alloc(root, ins->objectid, root->nodesize);
8188 return ret;
8189 }
8190
8191 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8192 struct btrfs_root *root,
8193 u64 root_objectid, u64 owner,
8194 u64 offset, u64 ram_bytes,
8195 struct btrfs_key *ins)
8196 {
8197 int ret;
8198
8199 BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
8200
8201 ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
8202 ins->offset, 0,
8203 root_objectid, owner, offset,
8204 ram_bytes, BTRFS_ADD_DELAYED_EXTENT,
8205 NULL);
8206 return ret;
8207 }
8208
8209 /*
8210 * this is used by the tree logging recovery code. It records that
8211 * an extent has been allocated and makes sure to clear the free
8212 * space cache bits as well
8213 */
8214 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
8215 struct btrfs_root *root,
8216 u64 root_objectid, u64 owner, u64 offset,
8217 struct btrfs_key *ins)
8218 {
8219 int ret;
8220 struct btrfs_block_group_cache *block_group;
8221 struct btrfs_space_info *space_info;
8222
8223 /*
8224 * Mixed block groups will exclude before processing the log so we only
8225 * need to do the exclude dance if this fs isn't mixed.
8226 */
8227 if (!btrfs_fs_incompat(root->fs_info, MIXED_GROUPS)) {
8228 ret = __exclude_logged_extent(root, ins->objectid, ins->offset);
8229 if (ret)
8230 return ret;
8231 }
8232
8233 block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
8234 if (!block_group)
8235 return -EINVAL;
8236
8237 space_info = block_group->space_info;
8238 spin_lock(&space_info->lock);
8239 spin_lock(&block_group->lock);
8240 space_info->bytes_reserved += ins->offset;
8241 block_group->reserved += ins->offset;
8242 spin_unlock(&block_group->lock);
8243 spin_unlock(&space_info->lock);
8244
8245 ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
8246 0, owner, offset, ins, 1);
8247 btrfs_put_block_group(block_group);
8248 return ret;
8249 }
8250
8251 static struct extent_buffer *
8252 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
8253 u64 bytenr, int level)
8254 {
8255 struct extent_buffer *buf;
8256
8257 buf = btrfs_find_create_tree_block(root, bytenr);
8258 if (IS_ERR(buf))
8259 return buf;
8260
8261 btrfs_set_header_generation(buf, trans->transid);
8262 btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
8263 btrfs_tree_lock(buf);
8264 clean_tree_block(trans, root->fs_info, buf);
8265 clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
8266
8267 btrfs_set_lock_blocking(buf);
8268 set_extent_buffer_uptodate(buf);
8269
8270 if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
8271 buf->log_index = root->log_transid % 2;
8272 /*
8273 * we allow two log transactions at a time, use different
8274 * EXENT bit to differentiate dirty pages.
8275 */
8276 if (buf->log_index == 0)
8277 set_extent_dirty(&root->dirty_log_pages, buf->start,
8278 buf->start + buf->len - 1, GFP_NOFS);
8279 else
8280 set_extent_new(&root->dirty_log_pages, buf->start,
8281 buf->start + buf->len - 1);
8282 } else {
8283 buf->log_index = -1;
8284 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
8285 buf->start + buf->len - 1, GFP_NOFS);
8286 }
8287 trans->dirty = true;
8288 /* this returns a buffer locked for blocking */
8289 return buf;
8290 }
8291
8292 static struct btrfs_block_rsv *
8293 use_block_rsv(struct btrfs_trans_handle *trans,
8294 struct btrfs_root *root, u32 blocksize)
8295 {
8296 struct btrfs_block_rsv *block_rsv;
8297 struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
8298 int ret;
8299 bool global_updated = false;
8300
8301 block_rsv = get_block_rsv(trans, root);
8302
8303 if (unlikely(block_rsv->size == 0))
8304 goto try_reserve;
8305 again:
8306 ret = block_rsv_use_bytes(block_rsv, blocksize);
8307 if (!ret)
8308 return block_rsv;
8309
8310 if (block_rsv->failfast)
8311 return ERR_PTR(ret);
8312
8313 if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
8314 global_updated = true;
8315 update_global_block_rsv(root->fs_info);
8316 goto again;
8317 }
8318
8319 if (btrfs_test_opt(root->fs_info, ENOSPC_DEBUG)) {
8320 static DEFINE_RATELIMIT_STATE(_rs,
8321 DEFAULT_RATELIMIT_INTERVAL * 10,
8322 /*DEFAULT_RATELIMIT_BURST*/ 1);
8323 if (__ratelimit(&_rs))
8324 WARN(1, KERN_DEBUG
8325 "BTRFS: block rsv returned %d\n", ret);
8326 }
8327 try_reserve:
8328 ret = reserve_metadata_bytes(root, block_rsv, blocksize,
8329 BTRFS_RESERVE_NO_FLUSH);
8330 if (!ret)
8331 return block_rsv;
8332 /*
8333 * If we couldn't reserve metadata bytes try and use some from
8334 * the global reserve if its space type is the same as the global
8335 * reservation.
8336 */
8337 if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
8338 block_rsv->space_info == global_rsv->space_info) {
8339 ret = block_rsv_use_bytes(global_rsv, blocksize);
8340 if (!ret)
8341 return global_rsv;
8342 }
8343 return ERR_PTR(ret);
8344 }
8345
8346 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
8347 struct btrfs_block_rsv *block_rsv, u32 blocksize)
8348 {
8349 block_rsv_add_bytes(block_rsv, blocksize, 0);
8350 block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
8351 }
8352
8353 /*
8354 * finds a free extent and does all the dirty work required for allocation
8355 * returns the tree buffer or an ERR_PTR on error.
8356 */
8357 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
8358 struct btrfs_root *root,
8359 u64 parent, u64 root_objectid,
8360 struct btrfs_disk_key *key, int level,
8361 u64 hint, u64 empty_size)
8362 {
8363 struct btrfs_key ins;
8364 struct btrfs_block_rsv *block_rsv;
8365 struct extent_buffer *buf;
8366 struct btrfs_delayed_extent_op *extent_op;
8367 u64 flags = 0;
8368 int ret;
8369 u32 blocksize = root->nodesize;
8370 bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
8371 SKINNY_METADATA);
8372
8373 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
8374 if (btrfs_is_testing(root->fs_info)) {
8375 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
8376 level);
8377 if (!IS_ERR(buf))
8378 root->alloc_bytenr += blocksize;
8379 return buf;
8380 }
8381 #endif
8382
8383 block_rsv = use_block_rsv(trans, root, blocksize);
8384 if (IS_ERR(block_rsv))
8385 return ERR_CAST(block_rsv);
8386
8387 ret = btrfs_reserve_extent(root, blocksize, blocksize, blocksize,
8388 empty_size, hint, &ins, 0, 0);
8389 if (ret)
8390 goto out_unuse;
8391
8392 buf = btrfs_init_new_buffer(trans, root, ins.objectid, level);
8393 if (IS_ERR(buf)) {
8394 ret = PTR_ERR(buf);
8395 goto out_free_reserved;
8396 }
8397
8398 if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
8399 if (parent == 0)
8400 parent = ins.objectid;
8401 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
8402 } else
8403 BUG_ON(parent > 0);
8404
8405 if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
8406 extent_op = btrfs_alloc_delayed_extent_op();
8407 if (!extent_op) {
8408 ret = -ENOMEM;
8409 goto out_free_buf;
8410 }
8411 if (key)
8412 memcpy(&extent_op->key, key, sizeof(extent_op->key));
8413 else
8414 memset(&extent_op->key, 0, sizeof(extent_op->key));
8415 extent_op->flags_to_set = flags;
8416 extent_op->update_key = skinny_metadata ? false : true;
8417 extent_op->update_flags = true;
8418 extent_op->is_data = false;
8419 extent_op->level = level;
8420
8421 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
8422 ins.objectid, ins.offset,
8423 parent, root_objectid, level,
8424 BTRFS_ADD_DELAYED_EXTENT,
8425 extent_op);
8426 if (ret)
8427 goto out_free_delayed;
8428 }
8429 return buf;
8430
8431 out_free_delayed:
8432 btrfs_free_delayed_extent_op(extent_op);
8433 out_free_buf:
8434 free_extent_buffer(buf);
8435 out_free_reserved:
8436 btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 0);
8437 out_unuse:
8438 unuse_block_rsv(root->fs_info, block_rsv, blocksize);
8439 return ERR_PTR(ret);
8440 }
8441
8442 struct walk_control {
8443 u64 refs[BTRFS_MAX_LEVEL];
8444 u64 flags[BTRFS_MAX_LEVEL];
8445 struct btrfs_key update_progress;
8446 int stage;
8447 int level;
8448 int shared_level;
8449 int update_ref;
8450 int keep_locks;
8451 int reada_slot;
8452 int reada_count;
8453 int for_reloc;
8454 };
8455
8456 #define DROP_REFERENCE 1
8457 #define UPDATE_BACKREF 2
8458
8459 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
8460 struct btrfs_root *root,
8461 struct walk_control *wc,
8462 struct btrfs_path *path)
8463 {
8464 u64 bytenr;
8465 u64 generation;
8466 u64 refs;
8467 u64 flags;
8468 u32 nritems;
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
8487 for (slot = path->slots[wc->level]; slot < nritems; slot++) {
8488 if (nread >= wc->reada_count)
8489 break;
8490
8491 cond_resched();
8492 bytenr = btrfs_node_blockptr(eb, slot);
8493 generation = btrfs_node_ptr_generation(eb, slot);
8494
8495 if (slot == path->slots[wc->level])
8496 goto reada;
8497
8498 if (wc->stage == UPDATE_BACKREF &&
8499 generation <= root->root_key.offset)
8500 continue;
8501
8502 /* We don't lock the tree block, it's OK to be racy here */
8503 ret = btrfs_lookup_extent_info(trans, root, bytenr,
8504 wc->level - 1, 1, &refs,
8505 &flags);
8506 /* We don't care about errors in readahead. */
8507 if (ret < 0)
8508 continue;
8509 BUG_ON(refs == 0);
8510
8511 if (wc->stage == DROP_REFERENCE) {
8512 if (refs == 1)
8513 goto reada;
8514
8515 if (wc->level == 1 &&
8516 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8517 continue;
8518 if (!wc->update_ref ||
8519 generation <= root->root_key.offset)
8520 continue;
8521 btrfs_node_key_to_cpu(eb, &key, slot);
8522 ret = btrfs_comp_cpu_keys(&key,
8523 &wc->update_progress);
8524 if (ret < 0)
8525 continue;
8526 } else {
8527 if (wc->level == 1 &&
8528 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8529 continue;
8530 }
8531 reada:
8532 readahead_tree_block(root, bytenr);
8533 nread++;
8534 }
8535 wc->reada_slot = slot;
8536 }
8537
8538 static int account_leaf_items(struct btrfs_trans_handle *trans,
8539 struct btrfs_root *root,
8540 struct extent_buffer *eb)
8541 {
8542 int nr = btrfs_header_nritems(eb);
8543 int i, extent_type, ret;
8544 struct btrfs_key key;
8545 struct btrfs_file_extent_item *fi;
8546 u64 bytenr, num_bytes;
8547
8548 /* We can be called directly from walk_up_proc() */
8549 if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &root->fs_info->flags))
8550 return 0;
8551
8552 for (i = 0; i < nr; i++) {
8553 btrfs_item_key_to_cpu(eb, &key, i);
8554
8555 if (key.type != BTRFS_EXTENT_DATA_KEY)
8556 continue;
8557
8558 fi = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
8559 /* filter out non qgroup-accountable extents */
8560 extent_type = btrfs_file_extent_type(eb, fi);
8561
8562 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
8563 continue;
8564
8565 bytenr = btrfs_file_extent_disk_bytenr(eb, fi);
8566 if (!bytenr)
8567 continue;
8568
8569 num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
8570
8571 ret = btrfs_qgroup_insert_dirty_extent(trans, root->fs_info,
8572 bytenr, num_bytes, GFP_NOFS);
8573 if (ret)
8574 return ret;
8575 }
8576 return 0;
8577 }
8578
8579 /*
8580 * Walk up the tree from the bottom, freeing leaves and any interior
8581 * nodes which have had all slots visited. If a node (leaf or
8582 * interior) is freed, the node above it will have it's slot
8583 * incremented. The root node will never be freed.
8584 *
8585 * At the end of this function, we should have a path which has all
8586 * slots incremented to the next position for a search. If we need to
8587 * read a new node it will be NULL and the node above it will have the
8588 * correct slot selected for a later read.
8589 *
8590 * If we increment the root nodes slot counter past the number of
8591 * elements, 1 is returned to signal completion of the search.
8592 */
8593 static int adjust_slots_upwards(struct btrfs_root *root,
8594 struct btrfs_path *path, int root_level)
8595 {
8596 int level = 0;
8597 int nr, slot;
8598 struct extent_buffer *eb;
8599
8600 if (root_level == 0)
8601 return 1;
8602
8603 while (level <= root_level) {
8604 eb = path->nodes[level];
8605 nr = btrfs_header_nritems(eb);
8606 path->slots[level]++;
8607 slot = path->slots[level];
8608 if (slot >= nr || level == 0) {
8609 /*
8610 * Don't free the root - we will detect this
8611 * condition after our loop and return a
8612 * positive value for caller to stop walking the tree.
8613 */
8614 if (level != root_level) {
8615 btrfs_tree_unlock_rw(eb, path->locks[level]);
8616 path->locks[level] = 0;
8617
8618 free_extent_buffer(eb);
8619 path->nodes[level] = NULL;
8620 path->slots[level] = 0;
8621 }
8622 } else {
8623 /*
8624 * We have a valid slot to walk back down
8625 * from. Stop here so caller can process these
8626 * new nodes.
8627 */
8628 break;
8629 }
8630
8631 level++;
8632 }
8633
8634 eb = path->nodes[root_level];
8635 if (path->slots[root_level] >= btrfs_header_nritems(eb))
8636 return 1;
8637
8638 return 0;
8639 }
8640
8641 /*
8642 * root_eb is the subtree root and is locked before this function is called.
8643 */
8644 static int account_shared_subtree(struct btrfs_trans_handle *trans,
8645 struct btrfs_root *root,
8646 struct extent_buffer *root_eb,
8647 u64 root_gen,
8648 int root_level)
8649 {
8650 int ret = 0;
8651 int level;
8652 struct extent_buffer *eb = root_eb;
8653 struct btrfs_path *path = NULL;
8654
8655 BUG_ON(root_level < 0 || root_level > BTRFS_MAX_LEVEL);
8656 BUG_ON(root_eb == NULL);
8657
8658 if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &root->fs_info->flags))
8659 return 0;
8660
8661 if (!extent_buffer_uptodate(root_eb)) {
8662 ret = btrfs_read_buffer(root_eb, root_gen);
8663 if (ret)
8664 goto out;
8665 }
8666
8667 if (root_level == 0) {
8668 ret = account_leaf_items(trans, root, root_eb);
8669 goto out;
8670 }
8671
8672 path = btrfs_alloc_path();
8673 if (!path)
8674 return -ENOMEM;
8675
8676 /*
8677 * Walk down the tree. Missing extent blocks are filled in as
8678 * we go. Metadata is accounted every time we read a new
8679 * extent block.
8680 *
8681 * When we reach a leaf, we account for file extent items in it,
8682 * walk back up the tree (adjusting slot pointers as we go)
8683 * and restart the search process.
8684 */
8685 extent_buffer_get(root_eb); /* For path */
8686 path->nodes[root_level] = root_eb;
8687 path->slots[root_level] = 0;
8688 path->locks[root_level] = 0; /* so release_path doesn't try to unlock */
8689 walk_down:
8690 level = root_level;
8691 while (level >= 0) {
8692 if (path->nodes[level] == NULL) {
8693 int parent_slot;
8694 u64 child_gen;
8695 u64 child_bytenr;
8696
8697 /* We need to get child blockptr/gen from
8698 * parent before we can read it. */
8699 eb = path->nodes[level + 1];
8700 parent_slot = path->slots[level + 1];
8701 child_bytenr = btrfs_node_blockptr(eb, parent_slot);
8702 child_gen = btrfs_node_ptr_generation(eb, parent_slot);
8703
8704 eb = read_tree_block(root, child_bytenr, child_gen);
8705 if (IS_ERR(eb)) {
8706 ret = PTR_ERR(eb);
8707 goto out;
8708 } else if (!extent_buffer_uptodate(eb)) {
8709 free_extent_buffer(eb);
8710 ret = -EIO;
8711 goto out;
8712 }
8713
8714 path->nodes[level] = eb;
8715 path->slots[level] = 0;
8716
8717 btrfs_tree_read_lock(eb);
8718 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
8719 path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
8720
8721 ret = btrfs_qgroup_insert_dirty_extent(trans,
8722 root->fs_info, child_bytenr,
8723 root->nodesize, GFP_NOFS);
8724 if (ret)
8725 goto out;
8726 }
8727
8728 if (level == 0) {
8729 ret = account_leaf_items(trans, root, path->nodes[level]);
8730 if (ret)
8731 goto out;
8732
8733 /* Nonzero return here means we completed our search */
8734 ret = adjust_slots_upwards(root, path, root_level);
8735 if (ret)
8736 break;
8737
8738 /* Restart search with new slots */
8739 goto walk_down;
8740 }
8741
8742 level--;
8743 }
8744
8745 ret = 0;
8746 out:
8747 btrfs_free_path(path);
8748
8749 return ret;
8750 }
8751
8752 /*
8753 * helper to process tree block while walking down the tree.
8754 *
8755 * when wc->stage == UPDATE_BACKREF, this function updates
8756 * back refs for pointers in the block.
8757 *
8758 * NOTE: return value 1 means we should stop walking down.
8759 */
8760 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
8761 struct btrfs_root *root,
8762 struct btrfs_path *path,
8763 struct walk_control *wc, int lookup_info)
8764 {
8765 int level = wc->level;
8766 struct extent_buffer *eb = path->nodes[level];
8767 u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8768 int ret;
8769
8770 if (wc->stage == UPDATE_BACKREF &&
8771 btrfs_header_owner(eb) != root->root_key.objectid)
8772 return 1;
8773
8774 /*
8775 * when reference count of tree block is 1, it won't increase
8776 * again. once full backref flag is set, we never clear it.
8777 */
8778 if (lookup_info &&
8779 ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
8780 (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
8781 BUG_ON(!path->locks[level]);
8782 ret = btrfs_lookup_extent_info(trans, root,
8783 eb->start, level, 1,
8784 &wc->refs[level],
8785 &wc->flags[level]);
8786 BUG_ON(ret == -ENOMEM);
8787 if (ret)
8788 return ret;
8789 BUG_ON(wc->refs[level] == 0);
8790 }
8791
8792 if (wc->stage == DROP_REFERENCE) {
8793 if (wc->refs[level] > 1)
8794 return 1;
8795
8796 if (path->locks[level] && !wc->keep_locks) {
8797 btrfs_tree_unlock_rw(eb, path->locks[level]);
8798 path->locks[level] = 0;
8799 }
8800 return 0;
8801 }
8802
8803 /* wc->stage == UPDATE_BACKREF */
8804 if (!(wc->flags[level] & flag)) {
8805 BUG_ON(!path->locks[level]);
8806 ret = btrfs_inc_ref(trans, root, eb, 1);
8807 BUG_ON(ret); /* -ENOMEM */
8808 ret = btrfs_dec_ref(trans, root, eb, 0);
8809 BUG_ON(ret); /* -ENOMEM */
8810 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
8811 eb->len, flag,
8812 btrfs_header_level(eb), 0);
8813 BUG_ON(ret); /* -ENOMEM */
8814 wc->flags[level] |= flag;
8815 }
8816
8817 /*
8818 * the block is shared by multiple trees, so it's not good to
8819 * keep the tree lock
8820 */
8821 if (path->locks[level] && level > 0) {
8822 btrfs_tree_unlock_rw(eb, path->locks[level]);
8823 path->locks[level] = 0;
8824 }
8825 return 0;
8826 }
8827
8828 /*
8829 * helper to process tree block pointer.
8830 *
8831 * when wc->stage == DROP_REFERENCE, this function checks
8832 * reference count of the block pointed to. if the block
8833 * is shared and we need update back refs for the subtree
8834 * rooted at the block, this function changes wc->stage to
8835 * UPDATE_BACKREF. if the block is shared and there is no
8836 * need to update back, this function drops the reference
8837 * to the block.
8838 *
8839 * NOTE: return value 1 means we should stop walking down.
8840 */
8841 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
8842 struct btrfs_root *root,
8843 struct btrfs_path *path,
8844 struct walk_control *wc, int *lookup_info)
8845 {
8846 u64 bytenr;
8847 u64 generation;
8848 u64 parent;
8849 u32 blocksize;
8850 struct btrfs_key key;
8851 struct extent_buffer *next;
8852 int level = wc->level;
8853 int reada = 0;
8854 int ret = 0;
8855 bool need_account = false;
8856
8857 generation = btrfs_node_ptr_generation(path->nodes[level],
8858 path->slots[level]);
8859 /*
8860 * if the lower level block was created before the snapshot
8861 * was created, we know there is no need to update back refs
8862 * for the subtree
8863 */
8864 if (wc->stage == UPDATE_BACKREF &&
8865 generation <= root->root_key.offset) {
8866 *lookup_info = 1;
8867 return 1;
8868 }
8869
8870 bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
8871 blocksize = root->nodesize;
8872
8873 next = btrfs_find_tree_block(root->fs_info, bytenr);
8874 if (!next) {
8875 next = btrfs_find_create_tree_block(root, bytenr);
8876 if (IS_ERR(next))
8877 return PTR_ERR(next);
8878
8879 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
8880 level - 1);
8881 reada = 1;
8882 }
8883 btrfs_tree_lock(next);
8884 btrfs_set_lock_blocking(next);
8885
8886 ret = btrfs_lookup_extent_info(trans, root, bytenr, level - 1, 1,
8887 &wc->refs[level - 1],
8888 &wc->flags[level - 1]);
8889 if (ret < 0)
8890 goto out_unlock;
8891
8892 if (unlikely(wc->refs[level - 1] == 0)) {
8893 btrfs_err(root->fs_info, "Missing references.");
8894 ret = -EIO;
8895 goto out_unlock;
8896 }
8897 *lookup_info = 0;
8898
8899 if (wc->stage == DROP_REFERENCE) {
8900 if (wc->refs[level - 1] > 1) {
8901 need_account = true;
8902 if (level == 1 &&
8903 (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8904 goto skip;
8905
8906 if (!wc->update_ref ||
8907 generation <= root->root_key.offset)
8908 goto skip;
8909
8910 btrfs_node_key_to_cpu(path->nodes[level], &key,
8911 path->slots[level]);
8912 ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
8913 if (ret < 0)
8914 goto skip;
8915
8916 wc->stage = UPDATE_BACKREF;
8917 wc->shared_level = level - 1;
8918 }
8919 } else {
8920 if (level == 1 &&
8921 (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8922 goto skip;
8923 }
8924
8925 if (!btrfs_buffer_uptodate(next, generation, 0)) {
8926 btrfs_tree_unlock(next);
8927 free_extent_buffer(next);
8928 next = NULL;
8929 *lookup_info = 1;
8930 }
8931
8932 if (!next) {
8933 if (reada && level == 1)
8934 reada_walk_down(trans, root, wc, path);
8935 next = read_tree_block(root, bytenr, generation);
8936 if (IS_ERR(next)) {
8937 return PTR_ERR(next);
8938 } else if (!extent_buffer_uptodate(next)) {
8939 free_extent_buffer(next);
8940 return -EIO;
8941 }
8942 btrfs_tree_lock(next);
8943 btrfs_set_lock_blocking(next);
8944 }
8945
8946 level--;
8947 ASSERT(level == btrfs_header_level(next));
8948 if (level != btrfs_header_level(next)) {
8949 btrfs_err(root->fs_info, "mismatched level");
8950 ret = -EIO;
8951 goto out_unlock;
8952 }
8953 path->nodes[level] = next;
8954 path->slots[level] = 0;
8955 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8956 wc->level = level;
8957 if (wc->level == 1)
8958 wc->reada_slot = 0;
8959 return 0;
8960 skip:
8961 wc->refs[level - 1] = 0;
8962 wc->flags[level - 1] = 0;
8963 if (wc->stage == DROP_REFERENCE) {
8964 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
8965 parent = path->nodes[level]->start;
8966 } else {
8967 ASSERT(root->root_key.objectid ==
8968 btrfs_header_owner(path->nodes[level]));
8969 if (root->root_key.objectid !=
8970 btrfs_header_owner(path->nodes[level])) {
8971 btrfs_err(root->fs_info,
8972 "mismatched block owner");
8973 ret = -EIO;
8974 goto out_unlock;
8975 }
8976 parent = 0;
8977 }
8978
8979 if (need_account) {
8980 ret = account_shared_subtree(trans, root, next,
8981 generation, level - 1);
8982 if (ret) {
8983 btrfs_err_rl(root->fs_info,
8984 "Error %d accounting shared subtree. Quota is out of sync, rescan required.",
8985 ret);
8986 }
8987 }
8988 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
8989 root->root_key.objectid, level - 1, 0);
8990 if (ret)
8991 goto out_unlock;
8992 }
8993
8994 *lookup_info = 1;
8995 ret = 1;
8996
8997 out_unlock:
8998 btrfs_tree_unlock(next);
8999 free_extent_buffer(next);
9000
9001 return ret;
9002 }
9003
9004 /*
9005 * helper to process tree block while walking up the tree.
9006 *
9007 * when wc->stage == DROP_REFERENCE, this function drops
9008 * reference count on the block.
9009 *
9010 * when wc->stage == UPDATE_BACKREF, this function changes
9011 * wc->stage back to DROP_REFERENCE if we changed wc->stage
9012 * to UPDATE_BACKREF previously while processing the block.
9013 *
9014 * NOTE: return value 1 means we should stop walking up.
9015 */
9016 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
9017 struct btrfs_root *root,
9018 struct btrfs_path *path,
9019 struct walk_control *wc)
9020 {
9021 int ret;
9022 int level = wc->level;
9023 struct extent_buffer *eb = path->nodes[level];
9024 u64 parent = 0;
9025
9026 if (wc->stage == UPDATE_BACKREF) {
9027 BUG_ON(wc->shared_level < level);
9028 if (level < wc->shared_level)
9029 goto out;
9030
9031 ret = find_next_key(path, level + 1, &wc->update_progress);
9032 if (ret > 0)
9033 wc->update_ref = 0;
9034
9035 wc->stage = DROP_REFERENCE;
9036 wc->shared_level = -1;
9037 path->slots[level] = 0;
9038
9039 /*
9040 * check reference count again if the block isn't locked.
9041 * we should start walking down the tree again if reference
9042 * count is one.
9043 */
9044 if (!path->locks[level]) {
9045 BUG_ON(level == 0);
9046 btrfs_tree_lock(eb);
9047 btrfs_set_lock_blocking(eb);
9048 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9049
9050 ret = btrfs_lookup_extent_info(trans, root,
9051 eb->start, level, 1,
9052 &wc->refs[level],
9053 &wc->flags[level]);
9054 if (ret < 0) {
9055 btrfs_tree_unlock_rw(eb, path->locks[level]);
9056 path->locks[level] = 0;
9057 return ret;
9058 }
9059 BUG_ON(wc->refs[level] == 0);
9060 if (wc->refs[level] == 1) {
9061 btrfs_tree_unlock_rw(eb, path->locks[level]);
9062 path->locks[level] = 0;
9063 return 1;
9064 }
9065 }
9066 }
9067
9068 /* wc->stage == DROP_REFERENCE */
9069 BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
9070
9071 if (wc->refs[level] == 1) {
9072 if (level == 0) {
9073 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
9074 ret = btrfs_dec_ref(trans, root, eb, 1);
9075 else
9076 ret = btrfs_dec_ref(trans, root, eb, 0);
9077 BUG_ON(ret); /* -ENOMEM */
9078 ret = account_leaf_items(trans, root, eb);
9079 if (ret) {
9080 btrfs_err_rl(root->fs_info,
9081 "error %d accounting leaf items. Quota is out of sync, rescan required.",
9082 ret);
9083 }
9084 }
9085 /* make block locked assertion in clean_tree_block happy */
9086 if (!path->locks[level] &&
9087 btrfs_header_generation(eb) == trans->transid) {
9088 btrfs_tree_lock(eb);
9089 btrfs_set_lock_blocking(eb);
9090 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9091 }
9092 clean_tree_block(trans, root->fs_info, eb);
9093 }
9094
9095 if (eb == root->node) {
9096 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
9097 parent = eb->start;
9098 else
9099 BUG_ON(root->root_key.objectid !=
9100 btrfs_header_owner(eb));
9101 } else {
9102 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
9103 parent = path->nodes[level + 1]->start;
9104 else
9105 BUG_ON(root->root_key.objectid !=
9106 btrfs_header_owner(path->nodes[level + 1]));
9107 }
9108
9109 btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
9110 out:
9111 wc->refs[level] = 0;
9112 wc->flags[level] = 0;
9113 return 0;
9114 }
9115
9116 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
9117 struct btrfs_root *root,
9118 struct btrfs_path *path,
9119 struct walk_control *wc)
9120 {
9121 int level = wc->level;
9122 int lookup_info = 1;
9123 int ret;
9124
9125 while (level >= 0) {
9126 ret = walk_down_proc(trans, root, path, wc, lookup_info);
9127 if (ret > 0)
9128 break;
9129
9130 if (level == 0)
9131 break;
9132
9133 if (path->slots[level] >=
9134 btrfs_header_nritems(path->nodes[level]))
9135 break;
9136
9137 ret = do_walk_down(trans, root, path, wc, &lookup_info);
9138 if (ret > 0) {
9139 path->slots[level]++;
9140 continue;
9141 } else if (ret < 0)
9142 return ret;
9143 level = wc->level;
9144 }
9145 return 0;
9146 }
9147
9148 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
9149 struct btrfs_root *root,
9150 struct btrfs_path *path,
9151 struct walk_control *wc, int max_level)
9152 {
9153 int level = wc->level;
9154 int ret;
9155
9156 path->slots[level] = btrfs_header_nritems(path->nodes[level]);
9157 while (level < max_level && path->nodes[level]) {
9158 wc->level = level;
9159 if (path->slots[level] + 1 <
9160 btrfs_header_nritems(path->nodes[level])) {
9161 path->slots[level]++;
9162 return 0;
9163 } else {
9164 ret = walk_up_proc(trans, root, path, wc);
9165 if (ret > 0)
9166 return 0;
9167
9168 if (path->locks[level]) {
9169 btrfs_tree_unlock_rw(path->nodes[level],
9170 path->locks[level]);
9171 path->locks[level] = 0;
9172 }
9173 free_extent_buffer(path->nodes[level]);
9174 path->nodes[level] = NULL;
9175 level++;
9176 }
9177 }
9178 return 1;
9179 }
9180
9181 /*
9182 * drop a subvolume tree.
9183 *
9184 * this function traverses the tree freeing any blocks that only
9185 * referenced by the tree.
9186 *
9187 * when a shared tree block is found. this function decreases its
9188 * reference count by one. if update_ref is true, this function
9189 * also make sure backrefs for the shared block and all lower level
9190 * blocks are properly updated.
9191 *
9192 * If called with for_reloc == 0, may exit early with -EAGAIN
9193 */
9194 int btrfs_drop_snapshot(struct btrfs_root *root,
9195 struct btrfs_block_rsv *block_rsv, int update_ref,
9196 int for_reloc)
9197 {
9198 struct btrfs_fs_info *fs_info = root->fs_info;
9199 struct btrfs_path *path;
9200 struct btrfs_trans_handle *trans;
9201 struct btrfs_root *tree_root = fs_info->tree_root;
9202 struct btrfs_root_item *root_item = &root->root_item;
9203 struct walk_control *wc;
9204 struct btrfs_key key;
9205 int err = 0;
9206 int ret;
9207 int level;
9208 bool root_dropped = false;
9209
9210 btrfs_debug(fs_info, "Drop subvolume %llu", root->objectid);
9211
9212 path = btrfs_alloc_path();
9213 if (!path) {
9214 err = -ENOMEM;
9215 goto out;
9216 }
9217
9218 wc = kzalloc(sizeof(*wc), GFP_NOFS);
9219 if (!wc) {
9220 btrfs_free_path(path);
9221 err = -ENOMEM;
9222 goto out;
9223 }
9224
9225 trans = btrfs_start_transaction(tree_root, 0);
9226 if (IS_ERR(trans)) {
9227 err = PTR_ERR(trans);
9228 goto out_free;
9229 }
9230
9231 if (block_rsv)
9232 trans->block_rsv = block_rsv;
9233
9234 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
9235 level = btrfs_header_level(root->node);
9236 path->nodes[level] = btrfs_lock_root_node(root);
9237 btrfs_set_lock_blocking(path->nodes[level]);
9238 path->slots[level] = 0;
9239 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9240 memset(&wc->update_progress, 0,
9241 sizeof(wc->update_progress));
9242 } else {
9243 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
9244 memcpy(&wc->update_progress, &key,
9245 sizeof(wc->update_progress));
9246
9247 level = root_item->drop_level;
9248 BUG_ON(level == 0);
9249 path->lowest_level = level;
9250 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
9251 path->lowest_level = 0;
9252 if (ret < 0) {
9253 err = ret;
9254 goto out_end_trans;
9255 }
9256 WARN_ON(ret > 0);
9257
9258 /*
9259 * unlock our path, this is safe because only this
9260 * function is allowed to delete this snapshot
9261 */
9262 btrfs_unlock_up_safe(path, 0);
9263
9264 level = btrfs_header_level(root->node);
9265 while (1) {
9266 btrfs_tree_lock(path->nodes[level]);
9267 btrfs_set_lock_blocking(path->nodes[level]);
9268 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9269
9270 ret = btrfs_lookup_extent_info(trans, root,
9271 path->nodes[level]->start,
9272 level, 1, &wc->refs[level],
9273 &wc->flags[level]);
9274 if (ret < 0) {
9275 err = ret;
9276 goto out_end_trans;
9277 }
9278 BUG_ON(wc->refs[level] == 0);
9279
9280 if (level == root_item->drop_level)
9281 break;
9282
9283 btrfs_tree_unlock(path->nodes[level]);
9284 path->locks[level] = 0;
9285 WARN_ON(wc->refs[level] != 1);
9286 level--;
9287 }
9288 }
9289
9290 wc->level = level;
9291 wc->shared_level = -1;
9292 wc->stage = DROP_REFERENCE;
9293 wc->update_ref = update_ref;
9294 wc->keep_locks = 0;
9295 wc->for_reloc = for_reloc;
9296 wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
9297
9298 while (1) {
9299
9300 ret = walk_down_tree(trans, root, path, wc);
9301 if (ret < 0) {
9302 err = ret;
9303 break;
9304 }
9305
9306 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
9307 if (ret < 0) {
9308 err = ret;
9309 break;
9310 }
9311
9312 if (ret > 0) {
9313 BUG_ON(wc->stage != DROP_REFERENCE);
9314 break;
9315 }
9316
9317 if (wc->stage == DROP_REFERENCE) {
9318 level = wc->level;
9319 btrfs_node_key(path->nodes[level],
9320 &root_item->drop_progress,
9321 path->slots[level]);
9322 root_item->drop_level = level;
9323 }
9324
9325 BUG_ON(wc->level == 0);
9326 if (btrfs_should_end_transaction(trans, tree_root) ||
9327 (!for_reloc && btrfs_need_cleaner_sleep(root))) {
9328 ret = btrfs_update_root(trans, tree_root,
9329 &root->root_key,
9330 root_item);
9331 if (ret) {
9332 btrfs_abort_transaction(trans, ret);
9333 err = ret;
9334 goto out_end_trans;
9335 }
9336
9337 btrfs_end_transaction_throttle(trans, tree_root);
9338 if (!for_reloc && btrfs_need_cleaner_sleep(root)) {
9339 btrfs_debug(fs_info,
9340 "drop snapshot early exit");
9341 err = -EAGAIN;
9342 goto out_free;
9343 }
9344
9345 trans = btrfs_start_transaction(tree_root, 0);
9346 if (IS_ERR(trans)) {
9347 err = PTR_ERR(trans);
9348 goto out_free;
9349 }
9350 if (block_rsv)
9351 trans->block_rsv = block_rsv;
9352 }
9353 }
9354 btrfs_release_path(path);
9355 if (err)
9356 goto out_end_trans;
9357
9358 ret = btrfs_del_root(trans, tree_root, &root->root_key);
9359 if (ret) {
9360 btrfs_abort_transaction(trans, ret);
9361 goto out_end_trans;
9362 }
9363
9364 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
9365 ret = btrfs_find_root(tree_root, &root->root_key, path,
9366 NULL, NULL);
9367 if (ret < 0) {
9368 btrfs_abort_transaction(trans, ret);
9369 err = ret;
9370 goto out_end_trans;
9371 } else if (ret > 0) {
9372 /* if we fail to delete the orphan item this time
9373 * around, it'll get picked up the next time.
9374 *
9375 * The most common failure here is just -ENOENT.
9376 */
9377 btrfs_del_orphan_item(trans, tree_root,
9378 root->root_key.objectid);
9379 }
9380 }
9381
9382 if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
9383 btrfs_add_dropped_root(trans, root);
9384 } else {
9385 free_extent_buffer(root->node);
9386 free_extent_buffer(root->commit_root);
9387 btrfs_put_fs_root(root);
9388 }
9389 root_dropped = true;
9390 out_end_trans:
9391 btrfs_end_transaction_throttle(trans, tree_root);
9392 out_free:
9393 kfree(wc);
9394 btrfs_free_path(path);
9395 out:
9396 /*
9397 * So if we need to stop dropping the snapshot for whatever reason we
9398 * need to make sure to add it back to the dead root list so that we
9399 * keep trying to do the work later. This also cleans up roots if we
9400 * don't have it in the radix (like when we recover after a power fail
9401 * or unmount) so we don't leak memory.
9402 */
9403 if (!for_reloc && root_dropped == false)
9404 btrfs_add_dead_root(root);
9405 if (err && err != -EAGAIN)
9406 btrfs_handle_fs_error(fs_info, err, NULL);
9407 return err;
9408 }
9409
9410 /*
9411 * drop subtree rooted at tree block 'node'.
9412 *
9413 * NOTE: this function will unlock and release tree block 'node'
9414 * only used by relocation code
9415 */
9416 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
9417 struct btrfs_root *root,
9418 struct extent_buffer *node,
9419 struct extent_buffer *parent)
9420 {
9421 struct btrfs_path *path;
9422 struct walk_control *wc;
9423 int level;
9424 int parent_level;
9425 int ret = 0;
9426 int wret;
9427
9428 BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
9429
9430 path = btrfs_alloc_path();
9431 if (!path)
9432 return -ENOMEM;
9433
9434 wc = kzalloc(sizeof(*wc), GFP_NOFS);
9435 if (!wc) {
9436 btrfs_free_path(path);
9437 return -ENOMEM;
9438 }
9439
9440 btrfs_assert_tree_locked(parent);
9441 parent_level = btrfs_header_level(parent);
9442 extent_buffer_get(parent);
9443 path->nodes[parent_level] = parent;
9444 path->slots[parent_level] = btrfs_header_nritems(parent);
9445
9446 btrfs_assert_tree_locked(node);
9447 level = btrfs_header_level(node);
9448 path->nodes[level] = node;
9449 path->slots[level] = 0;
9450 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9451
9452 wc->refs[parent_level] = 1;
9453 wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
9454 wc->level = level;
9455 wc->shared_level = -1;
9456 wc->stage = DROP_REFERENCE;
9457 wc->update_ref = 0;
9458 wc->keep_locks = 1;
9459 wc->for_reloc = 1;
9460 wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
9461
9462 while (1) {
9463 wret = walk_down_tree(trans, root, path, wc);
9464 if (wret < 0) {
9465 ret = wret;
9466 break;
9467 }
9468
9469 wret = walk_up_tree(trans, root, path, wc, parent_level);
9470 if (wret < 0)
9471 ret = wret;
9472 if (wret != 0)
9473 break;
9474 }
9475
9476 kfree(wc);
9477 btrfs_free_path(path);
9478 return ret;
9479 }
9480
9481 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
9482 {
9483 u64 num_devices;
9484 u64 stripped;
9485
9486 /*
9487 * if restripe for this chunk_type is on pick target profile and
9488 * return, otherwise do the usual balance
9489 */
9490 stripped = get_restripe_target(root->fs_info, flags);
9491 if (stripped)
9492 return extended_to_chunk(stripped);
9493
9494 num_devices = root->fs_info->fs_devices->rw_devices;
9495
9496 stripped = BTRFS_BLOCK_GROUP_RAID0 |
9497 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
9498 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
9499
9500 if (num_devices == 1) {
9501 stripped |= BTRFS_BLOCK_GROUP_DUP;
9502 stripped = flags & ~stripped;
9503
9504 /* turn raid0 into single device chunks */
9505 if (flags & BTRFS_BLOCK_GROUP_RAID0)
9506 return stripped;
9507
9508 /* turn mirroring into duplication */
9509 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
9510 BTRFS_BLOCK_GROUP_RAID10))
9511 return stripped | BTRFS_BLOCK_GROUP_DUP;
9512 } else {
9513 /* they already had raid on here, just return */
9514 if (flags & stripped)
9515 return flags;
9516
9517 stripped |= BTRFS_BLOCK_GROUP_DUP;
9518 stripped = flags & ~stripped;
9519
9520 /* switch duplicated blocks with raid1 */
9521 if (flags & BTRFS_BLOCK_GROUP_DUP)
9522 return stripped | BTRFS_BLOCK_GROUP_RAID1;
9523
9524 /* this is drive concat, leave it alone */
9525 }
9526
9527 return flags;
9528 }
9529
9530 static int inc_block_group_ro(struct btrfs_block_group_cache *cache, int force)
9531 {
9532 struct btrfs_space_info *sinfo = cache->space_info;
9533 u64 num_bytes;
9534 u64 min_allocable_bytes;
9535 int ret = -ENOSPC;
9536
9537 /*
9538 * We need some metadata space and system metadata space for
9539 * allocating chunks in some corner cases until we force to set
9540 * it to be readonly.
9541 */
9542 if ((sinfo->flags &
9543 (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
9544 !force)
9545 min_allocable_bytes = SZ_1M;
9546 else
9547 min_allocable_bytes = 0;
9548
9549 spin_lock(&sinfo->lock);
9550 spin_lock(&cache->lock);
9551
9552 if (cache->ro) {
9553 cache->ro++;
9554 ret = 0;
9555 goto out;
9556 }
9557
9558 num_bytes = cache->key.offset - cache->reserved - cache->pinned -
9559 cache->bytes_super - btrfs_block_group_used(&cache->item);
9560
9561 if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
9562 sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
9563 min_allocable_bytes <= sinfo->total_bytes) {
9564 sinfo->bytes_readonly += num_bytes;
9565 cache->ro++;
9566 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
9567 ret = 0;
9568 }
9569 out:
9570 spin_unlock(&cache->lock);
9571 spin_unlock(&sinfo->lock);
9572 return ret;
9573 }
9574
9575 int btrfs_inc_block_group_ro(struct btrfs_root *root,
9576 struct btrfs_block_group_cache *cache)
9577
9578 {
9579 struct btrfs_trans_handle *trans;
9580 u64 alloc_flags;
9581 int ret;
9582
9583 again:
9584 trans = btrfs_join_transaction(root);
9585 if (IS_ERR(trans))
9586 return PTR_ERR(trans);
9587
9588 /*
9589 * we're not allowed to set block groups readonly after the dirty
9590 * block groups cache has started writing. If it already started,
9591 * back off and let this transaction commit
9592 */
9593 mutex_lock(&root->fs_info->ro_block_group_mutex);
9594 if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
9595 u64 transid = trans->transid;
9596
9597 mutex_unlock(&root->fs_info->ro_block_group_mutex);
9598 btrfs_end_transaction(trans, root);
9599
9600 ret = btrfs_wait_for_commit(root, transid);
9601 if (ret)
9602 return ret;
9603 goto again;
9604 }
9605
9606 /*
9607 * if we are changing raid levels, try to allocate a corresponding
9608 * block group with the new raid level.
9609 */
9610 alloc_flags = update_block_group_flags(root, cache->flags);
9611 if (alloc_flags != cache->flags) {
9612 ret = do_chunk_alloc(trans, root, alloc_flags,
9613 CHUNK_ALLOC_FORCE);
9614 /*
9615 * ENOSPC is allowed here, we may have enough space
9616 * already allocated at the new raid level to
9617 * carry on
9618 */
9619 if (ret == -ENOSPC)
9620 ret = 0;
9621 if (ret < 0)
9622 goto out;
9623 }
9624
9625 ret = inc_block_group_ro(cache, 0);
9626 if (!ret)
9627 goto out;
9628 alloc_flags = get_alloc_profile(root, cache->space_info->flags);
9629 ret = do_chunk_alloc(trans, root, alloc_flags,
9630 CHUNK_ALLOC_FORCE);
9631 if (ret < 0)
9632 goto out;
9633 ret = inc_block_group_ro(cache, 0);
9634 out:
9635 if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
9636 alloc_flags = update_block_group_flags(root, cache->flags);
9637 lock_chunks(root->fs_info->chunk_root);
9638 check_system_chunk(trans, root, alloc_flags);
9639 unlock_chunks(root->fs_info->chunk_root);
9640 }
9641 mutex_unlock(&root->fs_info->ro_block_group_mutex);
9642
9643 btrfs_end_transaction(trans, root);
9644 return ret;
9645 }
9646
9647 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
9648 struct btrfs_root *root, u64 type)
9649 {
9650 u64 alloc_flags = get_alloc_profile(root, type);
9651 return do_chunk_alloc(trans, root, alloc_flags,
9652 CHUNK_ALLOC_FORCE);
9653 }
9654
9655 /*
9656 * helper to account the unused space of all the readonly block group in the
9657 * space_info. takes mirrors into account.
9658 */
9659 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
9660 {
9661 struct btrfs_block_group_cache *block_group;
9662 u64 free_bytes = 0;
9663 int factor;
9664
9665 /* It's df, we don't care if it's racy */
9666 if (list_empty(&sinfo->ro_bgs))
9667 return 0;
9668
9669 spin_lock(&sinfo->lock);
9670 list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
9671 spin_lock(&block_group->lock);
9672
9673 if (!block_group->ro) {
9674 spin_unlock(&block_group->lock);
9675 continue;
9676 }
9677
9678 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
9679 BTRFS_BLOCK_GROUP_RAID10 |
9680 BTRFS_BLOCK_GROUP_DUP))
9681 factor = 2;
9682 else
9683 factor = 1;
9684
9685 free_bytes += (block_group->key.offset -
9686 btrfs_block_group_used(&block_group->item)) *
9687 factor;
9688
9689 spin_unlock(&block_group->lock);
9690 }
9691 spin_unlock(&sinfo->lock);
9692
9693 return free_bytes;
9694 }
9695
9696 void btrfs_dec_block_group_ro(struct btrfs_root *root,
9697 struct btrfs_block_group_cache *cache)
9698 {
9699 struct btrfs_space_info *sinfo = cache->space_info;
9700 u64 num_bytes;
9701
9702 BUG_ON(!cache->ro);
9703
9704 spin_lock(&sinfo->lock);
9705 spin_lock(&cache->lock);
9706 if (!--cache->ro) {
9707 num_bytes = cache->key.offset - cache->reserved -
9708 cache->pinned - cache->bytes_super -
9709 btrfs_block_group_used(&cache->item);
9710 sinfo->bytes_readonly -= num_bytes;
9711 list_del_init(&cache->ro_list);
9712 }
9713 spin_unlock(&cache->lock);
9714 spin_unlock(&sinfo->lock);
9715 }
9716
9717 /*
9718 * checks to see if its even possible to relocate this block group.
9719 *
9720 * @return - -1 if it's not a good idea to relocate this block group, 0 if its
9721 * ok to go ahead and try.
9722 */
9723 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
9724 {
9725 struct btrfs_block_group_cache *block_group;
9726 struct btrfs_space_info *space_info;
9727 struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
9728 struct btrfs_device *device;
9729 struct btrfs_trans_handle *trans;
9730 u64 min_free;
9731 u64 dev_min = 1;
9732 u64 dev_nr = 0;
9733 u64 target;
9734 int debug;
9735 int index;
9736 int full = 0;
9737 int ret = 0;
9738
9739 debug = btrfs_test_opt(root->fs_info, ENOSPC_DEBUG);
9740
9741 block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
9742
9743 /* odd, couldn't find the block group, leave it alone */
9744 if (!block_group) {
9745 if (debug)
9746 btrfs_warn(root->fs_info,
9747 "can't find block group for bytenr %llu",
9748 bytenr);
9749 return -1;
9750 }
9751
9752 min_free = btrfs_block_group_used(&block_group->item);
9753
9754 /* no bytes used, we're good */
9755 if (!min_free)
9756 goto out;
9757
9758 space_info = block_group->space_info;
9759 spin_lock(&space_info->lock);
9760
9761 full = space_info->full;
9762
9763 /*
9764 * if this is the last block group we have in this space, we can't
9765 * relocate it unless we're able to allocate a new chunk below.
9766 *
9767 * Otherwise, we need to make sure we have room in the space to handle
9768 * all of the extents from this block group. If we can, we're good
9769 */
9770 if ((space_info->total_bytes != block_group->key.offset) &&
9771 (space_info->bytes_used + space_info->bytes_reserved +
9772 space_info->bytes_pinned + space_info->bytes_readonly +
9773 min_free < space_info->total_bytes)) {
9774 spin_unlock(&space_info->lock);
9775 goto out;
9776 }
9777 spin_unlock(&space_info->lock);
9778
9779 /*
9780 * ok we don't have enough space, but maybe we have free space on our
9781 * devices to allocate new chunks for relocation, so loop through our
9782 * alloc devices and guess if we have enough space. if this block
9783 * group is going to be restriped, run checks against the target
9784 * profile instead of the current one.
9785 */
9786 ret = -1;
9787
9788 /*
9789 * index:
9790 * 0: raid10
9791 * 1: raid1
9792 * 2: dup
9793 * 3: raid0
9794 * 4: single
9795 */
9796 target = get_restripe_target(root->fs_info, block_group->flags);
9797 if (target) {
9798 index = __get_raid_index(extended_to_chunk(target));
9799 } else {
9800 /*
9801 * this is just a balance, so if we were marked as full
9802 * we know there is no space for a new chunk
9803 */
9804 if (full) {
9805 if (debug)
9806 btrfs_warn(root->fs_info,
9807 "no space to alloc new chunk for block group %llu",
9808 block_group->key.objectid);
9809 goto out;
9810 }
9811
9812 index = get_block_group_index(block_group);
9813 }
9814
9815 if (index == BTRFS_RAID_RAID10) {
9816 dev_min = 4;
9817 /* Divide by 2 */
9818 min_free >>= 1;
9819 } else if (index == BTRFS_RAID_RAID1) {
9820 dev_min = 2;
9821 } else if (index == BTRFS_RAID_DUP) {
9822 /* Multiply by 2 */
9823 min_free <<= 1;
9824 } else if (index == BTRFS_RAID_RAID0) {
9825 dev_min = fs_devices->rw_devices;
9826 min_free = div64_u64(min_free, dev_min);
9827 }
9828
9829 /* We need to do this so that we can look at pending chunks */
9830 trans = btrfs_join_transaction(root);
9831 if (IS_ERR(trans)) {
9832 ret = PTR_ERR(trans);
9833 goto out;
9834 }
9835
9836 mutex_lock(&root->fs_info->chunk_mutex);
9837 list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
9838 u64 dev_offset;
9839
9840 /*
9841 * check to make sure we can actually find a chunk with enough
9842 * space to fit our block group in.
9843 */
9844 if (device->total_bytes > device->bytes_used + min_free &&
9845 !device->is_tgtdev_for_dev_replace) {
9846 ret = find_free_dev_extent(trans, device, min_free,
9847 &dev_offset, NULL);
9848 if (!ret)
9849 dev_nr++;
9850
9851 if (dev_nr >= dev_min)
9852 break;
9853
9854 ret = -1;
9855 }
9856 }
9857 if (debug && ret == -1)
9858 btrfs_warn(root->fs_info,
9859 "no space to allocate a new chunk for block group %llu",
9860 block_group->key.objectid);
9861 mutex_unlock(&root->fs_info->chunk_mutex);
9862 btrfs_end_transaction(trans, root);
9863 out:
9864 btrfs_put_block_group(block_group);
9865 return ret;
9866 }
9867
9868 static int find_first_block_group(struct btrfs_root *root,
9869 struct btrfs_path *path, struct btrfs_key *key)
9870 {
9871 int ret = 0;
9872 struct btrfs_key found_key;
9873 struct extent_buffer *leaf;
9874 int slot;
9875
9876 ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
9877 if (ret < 0)
9878 goto out;
9879
9880 while (1) {
9881 slot = path->slots[0];
9882 leaf = path->nodes[0];
9883 if (slot >= btrfs_header_nritems(leaf)) {
9884 ret = btrfs_next_leaf(root, path);
9885 if (ret == 0)
9886 continue;
9887 if (ret < 0)
9888 goto out;
9889 break;
9890 }
9891 btrfs_item_key_to_cpu(leaf, &found_key, slot);
9892
9893 if (found_key.objectid >= key->objectid &&
9894 found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
9895 struct extent_map_tree *em_tree;
9896 struct extent_map *em;
9897
9898 em_tree = &root->fs_info->mapping_tree.map_tree;
9899 read_lock(&em_tree->lock);
9900 em = lookup_extent_mapping(em_tree, found_key.objectid,
9901 found_key.offset);
9902 read_unlock(&em_tree->lock);
9903 if (!em) {
9904 btrfs_err(root->fs_info,
9905 "logical %llu len %llu found bg but no related chunk",
9906 found_key.objectid, found_key.offset);
9907 ret = -ENOENT;
9908 } else {
9909 ret = 0;
9910 }
9911 free_extent_map(em);
9912 goto out;
9913 }
9914 path->slots[0]++;
9915 }
9916 out:
9917 return ret;
9918 }
9919
9920 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
9921 {
9922 struct btrfs_block_group_cache *block_group;
9923 u64 last = 0;
9924
9925 while (1) {
9926 struct inode *inode;
9927
9928 block_group = btrfs_lookup_first_block_group(info, last);
9929 while (block_group) {
9930 spin_lock(&block_group->lock);
9931 if (block_group->iref)
9932 break;
9933 spin_unlock(&block_group->lock);
9934 block_group = next_block_group(info->tree_root,
9935 block_group);
9936 }
9937 if (!block_group) {
9938 if (last == 0)
9939 break;
9940 last = 0;
9941 continue;
9942 }
9943
9944 inode = block_group->inode;
9945 block_group->iref = 0;
9946 block_group->inode = NULL;
9947 spin_unlock(&block_group->lock);
9948 ASSERT(block_group->io_ctl.inode == NULL);
9949 iput(inode);
9950 last = block_group->key.objectid + block_group->key.offset;
9951 btrfs_put_block_group(block_group);
9952 }
9953 }
9954
9955 int btrfs_free_block_groups(struct btrfs_fs_info *info)
9956 {
9957 struct btrfs_block_group_cache *block_group;
9958 struct btrfs_space_info *space_info;
9959 struct btrfs_caching_control *caching_ctl;
9960 struct rb_node *n;
9961
9962 down_write(&info->commit_root_sem);
9963 while (!list_empty(&info->caching_block_groups)) {
9964 caching_ctl = list_entry(info->caching_block_groups.next,
9965 struct btrfs_caching_control, list);
9966 list_del(&caching_ctl->list);
9967 put_caching_control(caching_ctl);
9968 }
9969 up_write(&info->commit_root_sem);
9970
9971 spin_lock(&info->unused_bgs_lock);
9972 while (!list_empty(&info->unused_bgs)) {
9973 block_group = list_first_entry(&info->unused_bgs,
9974 struct btrfs_block_group_cache,
9975 bg_list);
9976 list_del_init(&block_group->bg_list);
9977 btrfs_put_block_group(block_group);
9978 }
9979 spin_unlock(&info->unused_bgs_lock);
9980
9981 spin_lock(&info->block_group_cache_lock);
9982 while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
9983 block_group = rb_entry(n, struct btrfs_block_group_cache,
9984 cache_node);
9985 rb_erase(&block_group->cache_node,
9986 &info->block_group_cache_tree);
9987 RB_CLEAR_NODE(&block_group->cache_node);
9988 spin_unlock(&info->block_group_cache_lock);
9989
9990 down_write(&block_group->space_info->groups_sem);
9991 list_del(&block_group->list);
9992 up_write(&block_group->space_info->groups_sem);
9993
9994 if (block_group->cached == BTRFS_CACHE_STARTED)
9995 wait_block_group_cache_done(block_group);
9996
9997 /*
9998 * We haven't cached this block group, which means we could
9999 * possibly have excluded extents on this block group.
10000 */
10001 if (block_group->cached == BTRFS_CACHE_NO ||
10002 block_group->cached == BTRFS_CACHE_ERROR)
10003 free_excluded_extents(info->extent_root, block_group);
10004
10005 btrfs_remove_free_space_cache(block_group);
10006 ASSERT(list_empty(&block_group->dirty_list));
10007 ASSERT(list_empty(&block_group->io_list));
10008 ASSERT(list_empty(&block_group->bg_list));
10009 ASSERT(atomic_read(&block_group->count) == 1);
10010 btrfs_put_block_group(block_group);
10011
10012 spin_lock(&info->block_group_cache_lock);
10013 }
10014 spin_unlock(&info->block_group_cache_lock);
10015
10016 /* now that all the block groups are freed, go through and
10017 * free all the space_info structs. This is only called during
10018 * the final stages of unmount, and so we know nobody is
10019 * using them. We call synchronize_rcu() once before we start,
10020 * just to be on the safe side.
10021 */
10022 synchronize_rcu();
10023
10024 release_global_block_rsv(info);
10025
10026 while (!list_empty(&info->space_info)) {
10027 int i;
10028
10029 space_info = list_entry(info->space_info.next,
10030 struct btrfs_space_info,
10031 list);
10032
10033 /*
10034 * Do not hide this behind enospc_debug, this is actually
10035 * important and indicates a real bug if this happens.
10036 */
10037 if (WARN_ON(space_info->bytes_pinned > 0 ||
10038 space_info->bytes_reserved > 0 ||
10039 space_info->bytes_may_use > 0))
10040 dump_space_info(info, space_info, 0, 0);
10041 list_del(&space_info->list);
10042 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
10043 struct kobject *kobj;
10044 kobj = space_info->block_group_kobjs[i];
10045 space_info->block_group_kobjs[i] = NULL;
10046 if (kobj) {
10047 kobject_del(kobj);
10048 kobject_put(kobj);
10049 }
10050 }
10051 kobject_del(&space_info->kobj);
10052 kobject_put(&space_info->kobj);
10053 }
10054 return 0;
10055 }
10056
10057 static void __link_block_group(struct btrfs_space_info *space_info,
10058 struct btrfs_block_group_cache *cache)
10059 {
10060 int index = get_block_group_index(cache);
10061 bool first = false;
10062
10063 down_write(&space_info->groups_sem);
10064 if (list_empty(&space_info->block_groups[index]))
10065 first = true;
10066 list_add_tail(&cache->list, &space_info->block_groups[index]);
10067 up_write(&space_info->groups_sem);
10068
10069 if (first) {
10070 struct raid_kobject *rkobj;
10071 int ret;
10072
10073 rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
10074 if (!rkobj)
10075 goto out_err;
10076 rkobj->raid_type = index;
10077 kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
10078 ret = kobject_add(&rkobj->kobj, &space_info->kobj,
10079 "%s", get_raid_name(index));
10080 if (ret) {
10081 kobject_put(&rkobj->kobj);
10082 goto out_err;
10083 }
10084 space_info->block_group_kobjs[index] = &rkobj->kobj;
10085 }
10086
10087 return;
10088 out_err:
10089 btrfs_warn(cache->fs_info,
10090 "failed to add kobject for block cache, ignoring");
10091 }
10092
10093 static struct btrfs_block_group_cache *
10094 btrfs_create_block_group_cache(struct btrfs_root *root, u64 start, u64 size)
10095 {
10096 struct btrfs_block_group_cache *cache;
10097
10098 cache = kzalloc(sizeof(*cache), GFP_NOFS);
10099 if (!cache)
10100 return NULL;
10101
10102 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
10103 GFP_NOFS);
10104 if (!cache->free_space_ctl) {
10105 kfree(cache);
10106 return NULL;
10107 }
10108
10109 cache->key.objectid = start;
10110 cache->key.offset = size;
10111 cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
10112
10113 cache->sectorsize = root->sectorsize;
10114 cache->fs_info = root->fs_info;
10115 cache->full_stripe_len = btrfs_full_stripe_len(root,
10116 &root->fs_info->mapping_tree,
10117 start);
10118 set_free_space_tree_thresholds(cache);
10119
10120 atomic_set(&cache->count, 1);
10121 spin_lock_init(&cache->lock);
10122 init_rwsem(&cache->data_rwsem);
10123 INIT_LIST_HEAD(&cache->list);
10124 INIT_LIST_HEAD(&cache->cluster_list);
10125 INIT_LIST_HEAD(&cache->bg_list);
10126 INIT_LIST_HEAD(&cache->ro_list);
10127 INIT_LIST_HEAD(&cache->dirty_list);
10128 INIT_LIST_HEAD(&cache->io_list);
10129 btrfs_init_free_space_ctl(cache);
10130 atomic_set(&cache->trimming, 0);
10131 mutex_init(&cache->free_space_lock);
10132
10133 return cache;
10134 }
10135
10136 int btrfs_read_block_groups(struct btrfs_root *root)
10137 {
10138 struct btrfs_path *path;
10139 int ret;
10140 struct btrfs_block_group_cache *cache;
10141 struct btrfs_fs_info *info = root->fs_info;
10142 struct btrfs_space_info *space_info;
10143 struct btrfs_key key;
10144 struct btrfs_key found_key;
10145 struct extent_buffer *leaf;
10146 int need_clear = 0;
10147 u64 cache_gen;
10148 u64 feature;
10149 int mixed;
10150
10151 feature = btrfs_super_incompat_flags(info->super_copy);
10152 mixed = !!(feature & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS);
10153
10154 root = info->extent_root;
10155 key.objectid = 0;
10156 key.offset = 0;
10157 key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
10158 path = btrfs_alloc_path();
10159 if (!path)
10160 return -ENOMEM;
10161 path->reada = READA_FORWARD;
10162
10163 cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
10164 if (btrfs_test_opt(root->fs_info, SPACE_CACHE) &&
10165 btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
10166 need_clear = 1;
10167 if (btrfs_test_opt(root->fs_info, CLEAR_CACHE))
10168 need_clear = 1;
10169
10170 while (1) {
10171 ret = find_first_block_group(root, path, &key);
10172 if (ret > 0)
10173 break;
10174 if (ret != 0)
10175 goto error;
10176
10177 leaf = path->nodes[0];
10178 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
10179
10180 cache = btrfs_create_block_group_cache(root, found_key.objectid,
10181 found_key.offset);
10182 if (!cache) {
10183 ret = -ENOMEM;
10184 goto error;
10185 }
10186
10187 if (need_clear) {
10188 /*
10189 * When we mount with old space cache, we need to
10190 * set BTRFS_DC_CLEAR and set dirty flag.
10191 *
10192 * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
10193 * truncate the old free space cache inode and
10194 * setup a new one.
10195 * b) Setting 'dirty flag' makes sure that we flush
10196 * the new space cache info onto disk.
10197 */
10198 if (btrfs_test_opt(root->fs_info, SPACE_CACHE))
10199 cache->disk_cache_state = BTRFS_DC_CLEAR;
10200 }
10201
10202 read_extent_buffer(leaf, &cache->item,
10203 btrfs_item_ptr_offset(leaf, path->slots[0]),
10204 sizeof(cache->item));
10205 cache->flags = btrfs_block_group_flags(&cache->item);
10206 if (!mixed &&
10207 ((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
10208 (cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
10209 btrfs_err(info,
10210 "bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
10211 cache->key.objectid);
10212 ret = -EINVAL;
10213 goto error;
10214 }
10215
10216 key.objectid = found_key.objectid + found_key.offset;
10217 btrfs_release_path(path);
10218
10219 /*
10220 * We need to exclude the super stripes now so that the space
10221 * info has super bytes accounted for, otherwise we'll think
10222 * we have more space than we actually do.
10223 */
10224 ret = exclude_super_stripes(root, cache);
10225 if (ret) {
10226 /*
10227 * We may have excluded something, so call this just in
10228 * case.
10229 */
10230 free_excluded_extents(root, cache);
10231 btrfs_put_block_group(cache);
10232 goto error;
10233 }
10234
10235 /*
10236 * check for two cases, either we are full, and therefore
10237 * don't need to bother with the caching work since we won't
10238 * find any space, or we are empty, and we can just add all
10239 * the space in and be done with it. This saves us _alot_ of
10240 * time, particularly in the full case.
10241 */
10242 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
10243 cache->last_byte_to_unpin = (u64)-1;
10244 cache->cached = BTRFS_CACHE_FINISHED;
10245 free_excluded_extents(root, cache);
10246 } else if (btrfs_block_group_used(&cache->item) == 0) {
10247 cache->last_byte_to_unpin = (u64)-1;
10248 cache->cached = BTRFS_CACHE_FINISHED;
10249 add_new_free_space(cache, root->fs_info,
10250 found_key.objectid,
10251 found_key.objectid +
10252 found_key.offset);
10253 free_excluded_extents(root, cache);
10254 }
10255
10256 ret = btrfs_add_block_group_cache(root->fs_info, cache);
10257 if (ret) {
10258 btrfs_remove_free_space_cache(cache);
10259 btrfs_put_block_group(cache);
10260 goto error;
10261 }
10262
10263 trace_btrfs_add_block_group(root->fs_info, cache, 0);
10264 ret = update_space_info(info, cache->flags, found_key.offset,
10265 btrfs_block_group_used(&cache->item),
10266 cache->bytes_super, &space_info);
10267 if (ret) {
10268 btrfs_remove_free_space_cache(cache);
10269 spin_lock(&info->block_group_cache_lock);
10270 rb_erase(&cache->cache_node,
10271 &info->block_group_cache_tree);
10272 RB_CLEAR_NODE(&cache->cache_node);
10273 spin_unlock(&info->block_group_cache_lock);
10274 btrfs_put_block_group(cache);
10275 goto error;
10276 }
10277
10278 cache->space_info = space_info;
10279
10280 __link_block_group(space_info, cache);
10281
10282 set_avail_alloc_bits(root->fs_info, cache->flags);
10283 if (btrfs_chunk_readonly(root, cache->key.objectid)) {
10284 inc_block_group_ro(cache, 1);
10285 } else if (btrfs_block_group_used(&cache->item) == 0) {
10286 spin_lock(&info->unused_bgs_lock);
10287 /* Should always be true but just in case. */
10288 if (list_empty(&cache->bg_list)) {
10289 btrfs_get_block_group(cache);
10290 list_add_tail(&cache->bg_list,
10291 &info->unused_bgs);
10292 }
10293 spin_unlock(&info->unused_bgs_lock);
10294 }
10295 }
10296
10297 list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
10298 if (!(get_alloc_profile(root, space_info->flags) &
10299 (BTRFS_BLOCK_GROUP_RAID10 |
10300 BTRFS_BLOCK_GROUP_RAID1 |
10301 BTRFS_BLOCK_GROUP_RAID5 |
10302 BTRFS_BLOCK_GROUP_RAID6 |
10303 BTRFS_BLOCK_GROUP_DUP)))
10304 continue;
10305 /*
10306 * avoid allocating from un-mirrored block group if there are
10307 * mirrored block groups.
10308 */
10309 list_for_each_entry(cache,
10310 &space_info->block_groups[BTRFS_RAID_RAID0],
10311 list)
10312 inc_block_group_ro(cache, 1);
10313 list_for_each_entry(cache,
10314 &space_info->block_groups[BTRFS_RAID_SINGLE],
10315 list)
10316 inc_block_group_ro(cache, 1);
10317 }
10318
10319 init_global_block_rsv(info);
10320 ret = 0;
10321 error:
10322 btrfs_free_path(path);
10323 return ret;
10324 }
10325
10326 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
10327 struct btrfs_root *root)
10328 {
10329 struct btrfs_block_group_cache *block_group, *tmp;
10330 struct btrfs_root *extent_root = root->fs_info->extent_root;
10331 struct btrfs_block_group_item item;
10332 struct btrfs_key key;
10333 int ret = 0;
10334 bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
10335
10336 trans->can_flush_pending_bgs = false;
10337 list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
10338 if (ret)
10339 goto next;
10340
10341 spin_lock(&block_group->lock);
10342 memcpy(&item, &block_group->item, sizeof(item));
10343 memcpy(&key, &block_group->key, sizeof(key));
10344 spin_unlock(&block_group->lock);
10345
10346 ret = btrfs_insert_item(trans, extent_root, &key, &item,
10347 sizeof(item));
10348 if (ret)
10349 btrfs_abort_transaction(trans, ret);
10350 ret = btrfs_finish_chunk_alloc(trans, extent_root,
10351 key.objectid, key.offset);
10352 if (ret)
10353 btrfs_abort_transaction(trans, ret);
10354 add_block_group_free_space(trans, root->fs_info, block_group);
10355 /* already aborted the transaction if it failed. */
10356 next:
10357 list_del_init(&block_group->bg_list);
10358 }
10359 trans->can_flush_pending_bgs = can_flush_pending_bgs;
10360 }
10361
10362 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
10363 struct btrfs_root *root, u64 bytes_used,
10364 u64 type, u64 chunk_objectid, u64 chunk_offset,
10365 u64 size)
10366 {
10367 int ret;
10368 struct btrfs_root *extent_root;
10369 struct btrfs_block_group_cache *cache;
10370 extent_root = root->fs_info->extent_root;
10371
10372 btrfs_set_log_full_commit(root->fs_info, trans);
10373
10374 cache = btrfs_create_block_group_cache(root, chunk_offset, size);
10375 if (!cache)
10376 return -ENOMEM;
10377
10378 btrfs_set_block_group_used(&cache->item, bytes_used);
10379 btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
10380 btrfs_set_block_group_flags(&cache->item, type);
10381
10382 cache->flags = type;
10383 cache->last_byte_to_unpin = (u64)-1;
10384 cache->cached = BTRFS_CACHE_FINISHED;
10385 cache->needs_free_space = 1;
10386 ret = exclude_super_stripes(root, cache);
10387 if (ret) {
10388 /*
10389 * We may have excluded something, so call this just in
10390 * case.
10391 */
10392 free_excluded_extents(root, cache);
10393 btrfs_put_block_group(cache);
10394 return ret;
10395 }
10396
10397 add_new_free_space(cache, root->fs_info, chunk_offset,
10398 chunk_offset + size);
10399
10400 free_excluded_extents(root, cache);
10401
10402 #ifdef CONFIG_BTRFS_DEBUG
10403 if (btrfs_should_fragment_free_space(root, cache)) {
10404 u64 new_bytes_used = size - bytes_used;
10405
10406 bytes_used += new_bytes_used >> 1;
10407 fragment_free_space(root, cache);
10408 }
10409 #endif
10410 /*
10411 * Call to ensure the corresponding space_info object is created and
10412 * assigned to our block group, but don't update its counters just yet.
10413 * We want our bg to be added to the rbtree with its ->space_info set.
10414 */
10415 ret = update_space_info(root->fs_info, cache->flags, 0, 0, 0,
10416 &cache->space_info);
10417 if (ret) {
10418 btrfs_remove_free_space_cache(cache);
10419 btrfs_put_block_group(cache);
10420 return ret;
10421 }
10422
10423 ret = btrfs_add_block_group_cache(root->fs_info, cache);
10424 if (ret) {
10425 btrfs_remove_free_space_cache(cache);
10426 btrfs_put_block_group(cache);
10427 return ret;
10428 }
10429
10430 /*
10431 * Now that our block group has its ->space_info set and is inserted in
10432 * the rbtree, update the space info's counters.
10433 */
10434 trace_btrfs_add_block_group(root->fs_info, cache, 1);
10435 ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
10436 cache->bytes_super, &cache->space_info);
10437 if (ret) {
10438 btrfs_remove_free_space_cache(cache);
10439 spin_lock(&root->fs_info->block_group_cache_lock);
10440 rb_erase(&cache->cache_node,
10441 &root->fs_info->block_group_cache_tree);
10442 RB_CLEAR_NODE(&cache->cache_node);
10443 spin_unlock(&root->fs_info->block_group_cache_lock);
10444 btrfs_put_block_group(cache);
10445 return ret;
10446 }
10447 update_global_block_rsv(root->fs_info);
10448
10449 __link_block_group(cache->space_info, cache);
10450
10451 list_add_tail(&cache->bg_list, &trans->new_bgs);
10452
10453 set_avail_alloc_bits(extent_root->fs_info, type);
10454 return 0;
10455 }
10456
10457 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
10458 {
10459 u64 extra_flags = chunk_to_extended(flags) &
10460 BTRFS_EXTENDED_PROFILE_MASK;
10461
10462 write_seqlock(&fs_info->profiles_lock);
10463 if (flags & BTRFS_BLOCK_GROUP_DATA)
10464 fs_info->avail_data_alloc_bits &= ~extra_flags;
10465 if (flags & BTRFS_BLOCK_GROUP_METADATA)
10466 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
10467 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
10468 fs_info->avail_system_alloc_bits &= ~extra_flags;
10469 write_sequnlock(&fs_info->profiles_lock);
10470 }
10471
10472 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
10473 struct btrfs_root *root, u64 group_start,
10474 struct extent_map *em)
10475 {
10476 struct btrfs_path *path;
10477 struct btrfs_block_group_cache *block_group;
10478 struct btrfs_free_cluster *cluster;
10479 struct btrfs_root *tree_root = root->fs_info->tree_root;
10480 struct btrfs_key key;
10481 struct inode *inode;
10482 struct kobject *kobj = NULL;
10483 int ret;
10484 int index;
10485 int factor;
10486 struct btrfs_caching_control *caching_ctl = NULL;
10487 bool remove_em;
10488
10489 root = root->fs_info->extent_root;
10490
10491 block_group = btrfs_lookup_block_group(root->fs_info, group_start);
10492 BUG_ON(!block_group);
10493 BUG_ON(!block_group->ro);
10494
10495 /*
10496 * Free the reserved super bytes from this block group before
10497 * remove it.
10498 */
10499 free_excluded_extents(root, block_group);
10500
10501 memcpy(&key, &block_group->key, sizeof(key));
10502 index = get_block_group_index(block_group);
10503 if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
10504 BTRFS_BLOCK_GROUP_RAID1 |
10505 BTRFS_BLOCK_GROUP_RAID10))
10506 factor = 2;
10507 else
10508 factor = 1;
10509
10510 /* make sure this block group isn't part of an allocation cluster */
10511 cluster = &root->fs_info->data_alloc_cluster;
10512 spin_lock(&cluster->refill_lock);
10513 btrfs_return_cluster_to_free_space(block_group, cluster);
10514 spin_unlock(&cluster->refill_lock);
10515
10516 /*
10517 * make sure this block group isn't part of a metadata
10518 * allocation cluster
10519 */
10520 cluster = &root->fs_info->meta_alloc_cluster;
10521 spin_lock(&cluster->refill_lock);
10522 btrfs_return_cluster_to_free_space(block_group, cluster);
10523 spin_unlock(&cluster->refill_lock);
10524
10525 path = btrfs_alloc_path();
10526 if (!path) {
10527 ret = -ENOMEM;
10528 goto out;
10529 }
10530
10531 /*
10532 * get the inode first so any iput calls done for the io_list
10533 * aren't the final iput (no unlinks allowed now)
10534 */
10535 inode = lookup_free_space_inode(tree_root, block_group, path);
10536
10537 mutex_lock(&trans->transaction->cache_write_mutex);
10538 /*
10539 * make sure our free spache cache IO is done before remove the
10540 * free space inode
10541 */
10542 spin_lock(&trans->transaction->dirty_bgs_lock);
10543 if (!list_empty(&block_group->io_list)) {
10544 list_del_init(&block_group->io_list);
10545
10546 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
10547
10548 spin_unlock(&trans->transaction->dirty_bgs_lock);
10549 btrfs_wait_cache_io(root, trans, block_group,
10550 &block_group->io_ctl, path,
10551 block_group->key.objectid);
10552 btrfs_put_block_group(block_group);
10553 spin_lock(&trans->transaction->dirty_bgs_lock);
10554 }
10555
10556 if (!list_empty(&block_group->dirty_list)) {
10557 list_del_init(&block_group->dirty_list);
10558 btrfs_put_block_group(block_group);
10559 }
10560 spin_unlock(&trans->transaction->dirty_bgs_lock);
10561 mutex_unlock(&trans->transaction->cache_write_mutex);
10562
10563 if (!IS_ERR(inode)) {
10564 ret = btrfs_orphan_add(trans, inode);
10565 if (ret) {
10566 btrfs_add_delayed_iput(inode);
10567 goto out;
10568 }
10569 clear_nlink(inode);
10570 /* One for the block groups ref */
10571 spin_lock(&block_group->lock);
10572 if (block_group->iref) {
10573 block_group->iref = 0;
10574 block_group->inode = NULL;
10575 spin_unlock(&block_group->lock);
10576 iput(inode);
10577 } else {
10578 spin_unlock(&block_group->lock);
10579 }
10580 /* One for our lookup ref */
10581 btrfs_add_delayed_iput(inode);
10582 }
10583
10584 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
10585 key.offset = block_group->key.objectid;
10586 key.type = 0;
10587
10588 ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
10589 if (ret < 0)
10590 goto out;
10591 if (ret > 0)
10592 btrfs_release_path(path);
10593 if (ret == 0) {
10594 ret = btrfs_del_item(trans, tree_root, path);
10595 if (ret)
10596 goto out;
10597 btrfs_release_path(path);
10598 }
10599
10600 spin_lock(&root->fs_info->block_group_cache_lock);
10601 rb_erase(&block_group->cache_node,
10602 &root->fs_info->block_group_cache_tree);
10603 RB_CLEAR_NODE(&block_group->cache_node);
10604
10605 if (root->fs_info->first_logical_byte == block_group->key.objectid)
10606 root->fs_info->first_logical_byte = (u64)-1;
10607 spin_unlock(&root->fs_info->block_group_cache_lock);
10608
10609 down_write(&block_group->space_info->groups_sem);
10610 /*
10611 * we must use list_del_init so people can check to see if they
10612 * are still on the list after taking the semaphore
10613 */
10614 list_del_init(&block_group->list);
10615 if (list_empty(&block_group->space_info->block_groups[index])) {
10616 kobj = block_group->space_info->block_group_kobjs[index];
10617 block_group->space_info->block_group_kobjs[index] = NULL;
10618 clear_avail_alloc_bits(root->fs_info, block_group->flags);
10619 }
10620 up_write(&block_group->space_info->groups_sem);
10621 if (kobj) {
10622 kobject_del(kobj);
10623 kobject_put(kobj);
10624 }
10625
10626 if (block_group->has_caching_ctl)
10627 caching_ctl = get_caching_control(block_group);
10628 if (block_group->cached == BTRFS_CACHE_STARTED)
10629 wait_block_group_cache_done(block_group);
10630 if (block_group->has_caching_ctl) {
10631 down_write(&root->fs_info->commit_root_sem);
10632 if (!caching_ctl) {
10633 struct btrfs_caching_control *ctl;
10634
10635 list_for_each_entry(ctl,
10636 &root->fs_info->caching_block_groups, list)
10637 if (ctl->block_group == block_group) {
10638 caching_ctl = ctl;
10639 atomic_inc(&caching_ctl->count);
10640 break;
10641 }
10642 }
10643 if (caching_ctl)
10644 list_del_init(&caching_ctl->list);
10645 up_write(&root->fs_info->commit_root_sem);
10646 if (caching_ctl) {
10647 /* Once for the caching bgs list and once for us. */
10648 put_caching_control(caching_ctl);
10649 put_caching_control(caching_ctl);
10650 }
10651 }
10652
10653 spin_lock(&trans->transaction->dirty_bgs_lock);
10654 if (!list_empty(&block_group->dirty_list)) {
10655 WARN_ON(1);
10656 }
10657 if (!list_empty(&block_group->io_list)) {
10658 WARN_ON(1);
10659 }
10660 spin_unlock(&trans->transaction->dirty_bgs_lock);
10661 btrfs_remove_free_space_cache(block_group);
10662
10663 spin_lock(&block_group->space_info->lock);
10664 list_del_init(&block_group->ro_list);
10665
10666 if (btrfs_test_opt(root->fs_info, ENOSPC_DEBUG)) {
10667 WARN_ON(block_group->space_info->total_bytes
10668 < block_group->key.offset);
10669 WARN_ON(block_group->space_info->bytes_readonly
10670 < block_group->key.offset);
10671 WARN_ON(block_group->space_info->disk_total
10672 < block_group->key.offset * factor);
10673 }
10674 block_group->space_info->total_bytes -= block_group->key.offset;
10675 block_group->space_info->bytes_readonly -= block_group->key.offset;
10676 block_group->space_info->disk_total -= block_group->key.offset * factor;
10677
10678 spin_unlock(&block_group->space_info->lock);
10679
10680 memcpy(&key, &block_group->key, sizeof(key));
10681
10682 lock_chunks(root);
10683 if (!list_empty(&em->list)) {
10684 /* We're in the transaction->pending_chunks list. */
10685 free_extent_map(em);
10686 }
10687 spin_lock(&block_group->lock);
10688 block_group->removed = 1;
10689 /*
10690 * At this point trimming can't start on this block group, because we
10691 * removed the block group from the tree fs_info->block_group_cache_tree
10692 * so no one can't find it anymore and even if someone already got this
10693 * block group before we removed it from the rbtree, they have already
10694 * incremented block_group->trimming - if they didn't, they won't find
10695 * any free space entries because we already removed them all when we
10696 * called btrfs_remove_free_space_cache().
10697 *
10698 * And we must not remove the extent map from the fs_info->mapping_tree
10699 * to prevent the same logical address range and physical device space
10700 * ranges from being reused for a new block group. This is because our
10701 * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
10702 * completely transactionless, so while it is trimming a range the
10703 * currently running transaction might finish and a new one start,
10704 * allowing for new block groups to be created that can reuse the same
10705 * physical device locations unless we take this special care.
10706 *
10707 * There may also be an implicit trim operation if the file system
10708 * is mounted with -odiscard. The same protections must remain
10709 * in place until the extents have been discarded completely when
10710 * the transaction commit has completed.
10711 */
10712 remove_em = (atomic_read(&block_group->trimming) == 0);
10713 /*
10714 * Make sure a trimmer task always sees the em in the pinned_chunks list
10715 * if it sees block_group->removed == 1 (needs to lock block_group->lock
10716 * before checking block_group->removed).
10717 */
10718 if (!remove_em) {
10719 /*
10720 * Our em might be in trans->transaction->pending_chunks which
10721 * is protected by fs_info->chunk_mutex ([lock|unlock]_chunks),
10722 * and so is the fs_info->pinned_chunks list.
10723 *
10724 * So at this point we must be holding the chunk_mutex to avoid
10725 * any races with chunk allocation (more specifically at
10726 * volumes.c:contains_pending_extent()), to ensure it always
10727 * sees the em, either in the pending_chunks list or in the
10728 * pinned_chunks list.
10729 */
10730 list_move_tail(&em->list, &root->fs_info->pinned_chunks);
10731 }
10732 spin_unlock(&block_group->lock);
10733
10734 if (remove_em) {
10735 struct extent_map_tree *em_tree;
10736
10737 em_tree = &root->fs_info->mapping_tree.map_tree;
10738 write_lock(&em_tree->lock);
10739 /*
10740 * The em might be in the pending_chunks list, so make sure the
10741 * chunk mutex is locked, since remove_extent_mapping() will
10742 * delete us from that list.
10743 */
10744 remove_extent_mapping(em_tree, em);
10745 write_unlock(&em_tree->lock);
10746 /* once for the tree */
10747 free_extent_map(em);
10748 }
10749
10750 unlock_chunks(root);
10751
10752 ret = remove_block_group_free_space(trans, root->fs_info, block_group);
10753 if (ret)
10754 goto out;
10755
10756 btrfs_put_block_group(block_group);
10757 btrfs_put_block_group(block_group);
10758
10759 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
10760 if (ret > 0)
10761 ret = -EIO;
10762 if (ret < 0)
10763 goto out;
10764
10765 ret = btrfs_del_item(trans, root, path);
10766 out:
10767 btrfs_free_path(path);
10768 return ret;
10769 }
10770
10771 struct btrfs_trans_handle *
10772 btrfs_start_trans_remove_block_group(struct btrfs_fs_info *fs_info,
10773 const u64 chunk_offset)
10774 {
10775 struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree;
10776 struct extent_map *em;
10777 struct map_lookup *map;
10778 unsigned int num_items;
10779
10780 read_lock(&em_tree->lock);
10781 em = lookup_extent_mapping(em_tree, chunk_offset, 1);
10782 read_unlock(&em_tree->lock);
10783 ASSERT(em && em->start == chunk_offset);
10784
10785 /*
10786 * We need to reserve 3 + N units from the metadata space info in order
10787 * to remove a block group (done at btrfs_remove_chunk() and at
10788 * btrfs_remove_block_group()), which are used for:
10789 *
10790 * 1 unit for adding the free space inode's orphan (located in the tree
10791 * of tree roots).
10792 * 1 unit for deleting the block group item (located in the extent
10793 * tree).
10794 * 1 unit for deleting the free space item (located in tree of tree
10795 * roots).
10796 * N units for deleting N device extent items corresponding to each
10797 * stripe (located in the device tree).
10798 *
10799 * In order to remove a block group we also need to reserve units in the
10800 * system space info in order to update the chunk tree (update one or
10801 * more device items and remove one chunk item), but this is done at
10802 * btrfs_remove_chunk() through a call to check_system_chunk().
10803 */
10804 map = em->map_lookup;
10805 num_items = 3 + map->num_stripes;
10806 free_extent_map(em);
10807
10808 return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
10809 num_items, 1);
10810 }
10811
10812 /*
10813 * Process the unused_bgs list and remove any that don't have any allocated
10814 * space inside of them.
10815 */
10816 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
10817 {
10818 struct btrfs_block_group_cache *block_group;
10819 struct btrfs_space_info *space_info;
10820 struct btrfs_root *root = fs_info->extent_root;
10821 struct btrfs_trans_handle *trans;
10822 int ret = 0;
10823
10824 if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
10825 return;
10826
10827 spin_lock(&fs_info->unused_bgs_lock);
10828 while (!list_empty(&fs_info->unused_bgs)) {
10829 u64 start, end;
10830 int trimming;
10831
10832 block_group = list_first_entry(&fs_info->unused_bgs,
10833 struct btrfs_block_group_cache,
10834 bg_list);
10835 list_del_init(&block_group->bg_list);
10836
10837 space_info = block_group->space_info;
10838
10839 if (ret || btrfs_mixed_space_info(space_info)) {
10840 btrfs_put_block_group(block_group);
10841 continue;
10842 }
10843 spin_unlock(&fs_info->unused_bgs_lock);
10844
10845 mutex_lock(&fs_info->delete_unused_bgs_mutex);
10846
10847 /* Don't want to race with allocators so take the groups_sem */
10848 down_write(&space_info->groups_sem);
10849 spin_lock(&block_group->lock);
10850 if (block_group->reserved ||
10851 btrfs_block_group_used(&block_group->item) ||
10852 (block_group->ro && !block_group->removed) ||
10853 list_is_singular(&block_group->list)) {
10854 /*
10855 * We want to bail if we made new allocations or have
10856 * outstanding allocations in this block group. We do
10857 * the ro check in case balance is currently acting on
10858 * this block group.
10859 */
10860 spin_unlock(&block_group->lock);
10861 up_write(&space_info->groups_sem);
10862 goto next;
10863 }
10864 spin_unlock(&block_group->lock);
10865
10866 /* We don't want to force the issue, only flip if it's ok. */
10867 ret = inc_block_group_ro(block_group, 0);
10868 up_write(&space_info->groups_sem);
10869 if (ret < 0) {
10870 ret = 0;
10871 goto next;
10872 }
10873
10874 /*
10875 * Want to do this before we do anything else so we can recover
10876 * properly if we fail to join the transaction.
10877 */
10878 trans = btrfs_start_trans_remove_block_group(fs_info,
10879 block_group->key.objectid);
10880 if (IS_ERR(trans)) {
10881 btrfs_dec_block_group_ro(root, block_group);
10882 ret = PTR_ERR(trans);
10883 goto next;
10884 }
10885
10886 /*
10887 * We could have pending pinned extents for this block group,
10888 * just delete them, we don't care about them anymore.
10889 */
10890 start = block_group->key.objectid;
10891 end = start + block_group->key.offset - 1;
10892 /*
10893 * Hold the unused_bg_unpin_mutex lock to avoid racing with
10894 * btrfs_finish_extent_commit(). If we are at transaction N,
10895 * another task might be running finish_extent_commit() for the
10896 * previous transaction N - 1, and have seen a range belonging
10897 * to the block group in freed_extents[] before we were able to
10898 * clear the whole block group range from freed_extents[]. This
10899 * means that task can lookup for the block group after we
10900 * unpinned it from freed_extents[] and removed it, leading to
10901 * a BUG_ON() at btrfs_unpin_extent_range().
10902 */
10903 mutex_lock(&fs_info->unused_bg_unpin_mutex);
10904 ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
10905 EXTENT_DIRTY);
10906 if (ret) {
10907 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10908 btrfs_dec_block_group_ro(root, block_group);
10909 goto end_trans;
10910 }
10911 ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
10912 EXTENT_DIRTY);
10913 if (ret) {
10914 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10915 btrfs_dec_block_group_ro(root, block_group);
10916 goto end_trans;
10917 }
10918 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10919
10920 /* Reset pinned so btrfs_put_block_group doesn't complain */
10921 spin_lock(&space_info->lock);
10922 spin_lock(&block_group->lock);
10923
10924 space_info->bytes_pinned -= block_group->pinned;
10925 space_info->bytes_readonly += block_group->pinned;
10926 percpu_counter_add(&space_info->total_bytes_pinned,
10927 -block_group->pinned);
10928 block_group->pinned = 0;
10929
10930 spin_unlock(&block_group->lock);
10931 spin_unlock(&space_info->lock);
10932
10933 /* DISCARD can flip during remount */
10934 trimming = btrfs_test_opt(root->fs_info, DISCARD);
10935
10936 /* Implicit trim during transaction commit. */
10937 if (trimming)
10938 btrfs_get_block_group_trimming(block_group);
10939
10940 /*
10941 * Btrfs_remove_chunk will abort the transaction if things go
10942 * horribly wrong.
10943 */
10944 ret = btrfs_remove_chunk(trans, root,
10945 block_group->key.objectid);
10946
10947 if (ret) {
10948 if (trimming)
10949 btrfs_put_block_group_trimming(block_group);
10950 goto end_trans;
10951 }
10952
10953 /*
10954 * If we're not mounted with -odiscard, we can just forget
10955 * about this block group. Otherwise we'll need to wait
10956 * until transaction commit to do the actual discard.
10957 */
10958 if (trimming) {
10959 spin_lock(&fs_info->unused_bgs_lock);
10960 /*
10961 * A concurrent scrub might have added us to the list
10962 * fs_info->unused_bgs, so use a list_move operation
10963 * to add the block group to the deleted_bgs list.
10964 */
10965 list_move(&block_group->bg_list,
10966 &trans->transaction->deleted_bgs);
10967 spin_unlock(&fs_info->unused_bgs_lock);
10968 btrfs_get_block_group(block_group);
10969 }
10970 end_trans:
10971 btrfs_end_transaction(trans, root);
10972 next:
10973 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
10974 btrfs_put_block_group(block_group);
10975 spin_lock(&fs_info->unused_bgs_lock);
10976 }
10977 spin_unlock(&fs_info->unused_bgs_lock);
10978 }
10979
10980 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
10981 {
10982 struct btrfs_space_info *space_info;
10983 struct btrfs_super_block *disk_super;
10984 u64 features;
10985 u64 flags;
10986 int mixed = 0;
10987 int ret;
10988
10989 disk_super = fs_info->super_copy;
10990 if (!btrfs_super_root(disk_super))
10991 return -EINVAL;
10992
10993 features = btrfs_super_incompat_flags(disk_super);
10994 if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
10995 mixed = 1;
10996
10997 flags = BTRFS_BLOCK_GROUP_SYSTEM;
10998 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
10999 if (ret)
11000 goto out;
11001
11002 if (mixed) {
11003 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
11004 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
11005 } else {
11006 flags = BTRFS_BLOCK_GROUP_METADATA;
11007 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
11008 if (ret)
11009 goto out;
11010
11011 flags = BTRFS_BLOCK_GROUP_DATA;
11012 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
11013 }
11014 out:
11015 return ret;
11016 }
11017
11018 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
11019 {
11020 return unpin_extent_range(root, start, end, false);
11021 }
11022
11023 /*
11024 * It used to be that old block groups would be left around forever.
11025 * Iterating over them would be enough to trim unused space. Since we
11026 * now automatically remove them, we also need to iterate over unallocated
11027 * space.
11028 *
11029 * We don't want a transaction for this since the discard may take a
11030 * substantial amount of time. We don't require that a transaction be
11031 * running, but we do need to take a running transaction into account
11032 * to ensure that we're not discarding chunks that were released in
11033 * the current transaction.
11034 *
11035 * Holding the chunks lock will prevent other threads from allocating
11036 * or releasing chunks, but it won't prevent a running transaction
11037 * from committing and releasing the memory that the pending chunks
11038 * list head uses. For that, we need to take a reference to the
11039 * transaction.
11040 */
11041 static int btrfs_trim_free_extents(struct btrfs_device *device,
11042 u64 minlen, u64 *trimmed)
11043 {
11044 u64 start = 0, len = 0;
11045 int ret;
11046
11047 *trimmed = 0;
11048
11049 /* Not writeable = nothing to do. */
11050 if (!device->writeable)
11051 return 0;
11052
11053 /* No free space = nothing to do. */
11054 if (device->total_bytes <= device->bytes_used)
11055 return 0;
11056
11057 ret = 0;
11058
11059 while (1) {
11060 struct btrfs_fs_info *fs_info = device->dev_root->fs_info;
11061 struct btrfs_transaction *trans;
11062 u64 bytes;
11063
11064 ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
11065 if (ret)
11066 return ret;
11067
11068 down_read(&fs_info->commit_root_sem);
11069
11070 spin_lock(&fs_info->trans_lock);
11071 trans = fs_info->running_transaction;
11072 if (trans)
11073 atomic_inc(&trans->use_count);
11074 spin_unlock(&fs_info->trans_lock);
11075
11076 ret = find_free_dev_extent_start(trans, device, minlen, start,
11077 &start, &len);
11078 if (trans)
11079 btrfs_put_transaction(trans);
11080
11081 if (ret) {
11082 up_read(&fs_info->commit_root_sem);
11083 mutex_unlock(&fs_info->chunk_mutex);
11084 if (ret == -ENOSPC)
11085 ret = 0;
11086 break;
11087 }
11088
11089 ret = btrfs_issue_discard(device->bdev, start, len, &bytes);
11090 up_read(&fs_info->commit_root_sem);
11091 mutex_unlock(&fs_info->chunk_mutex);
11092
11093 if (ret)
11094 break;
11095
11096 start += len;
11097 *trimmed += bytes;
11098
11099 if (fatal_signal_pending(current)) {
11100 ret = -ERESTARTSYS;
11101 break;
11102 }
11103
11104 cond_resched();
11105 }
11106
11107 return ret;
11108 }
11109
11110 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
11111 {
11112 struct btrfs_fs_info *fs_info = root->fs_info;
11113 struct btrfs_block_group_cache *cache = NULL;
11114 struct btrfs_device *device;
11115 struct list_head *devices;
11116 u64 group_trimmed;
11117 u64 start;
11118 u64 end;
11119 u64 trimmed = 0;
11120 u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
11121 int ret = 0;
11122
11123 /*
11124 * try to trim all FS space, our block group may start from non-zero.
11125 */
11126 if (range->len == total_bytes)
11127 cache = btrfs_lookup_first_block_group(fs_info, range->start);
11128 else
11129 cache = btrfs_lookup_block_group(fs_info, range->start);
11130
11131 while (cache) {
11132 if (cache->key.objectid >= (range->start + range->len)) {
11133 btrfs_put_block_group(cache);
11134 break;
11135 }
11136
11137 start = max(range->start, cache->key.objectid);
11138 end = min(range->start + range->len,
11139 cache->key.objectid + cache->key.offset);
11140
11141 if (end - start >= range->minlen) {
11142 if (!block_group_cache_done(cache)) {
11143 ret = cache_block_group(cache, 0);
11144 if (ret) {
11145 btrfs_put_block_group(cache);
11146 break;
11147 }
11148 ret = wait_block_group_cache_done(cache);
11149 if (ret) {
11150 btrfs_put_block_group(cache);
11151 break;
11152 }
11153 }
11154 ret = btrfs_trim_block_group(cache,
11155 &group_trimmed,
11156 start,
11157 end,
11158 range->minlen);
11159
11160 trimmed += group_trimmed;
11161 if (ret) {
11162 btrfs_put_block_group(cache);
11163 break;
11164 }
11165 }
11166
11167 cache = next_block_group(fs_info->tree_root, cache);
11168 }
11169
11170 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
11171 devices = &root->fs_info->fs_devices->alloc_list;
11172 list_for_each_entry(device, devices, dev_alloc_list) {
11173 ret = btrfs_trim_free_extents(device, range->minlen,
11174 &group_trimmed);
11175 if (ret)
11176 break;
11177
11178 trimmed += group_trimmed;
11179 }
11180 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
11181
11182 range->len = trimmed;
11183 return ret;
11184 }
11185
11186 /*
11187 * btrfs_{start,end}_write_no_snapshoting() are similar to
11188 * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
11189 * data into the page cache through nocow before the subvolume is snapshoted,
11190 * but flush the data into disk after the snapshot creation, or to prevent
11191 * operations while snapshoting is ongoing and that cause the snapshot to be
11192 * inconsistent (writes followed by expanding truncates for example).
11193 */
11194 void btrfs_end_write_no_snapshoting(struct btrfs_root *root)
11195 {
11196 percpu_counter_dec(&root->subv_writers->counter);
11197 /*
11198 * Make sure counter is updated before we wake up waiters.
11199 */
11200 smp_mb();
11201 if (waitqueue_active(&root->subv_writers->wait))
11202 wake_up(&root->subv_writers->wait);
11203 }
11204
11205 int btrfs_start_write_no_snapshoting(struct btrfs_root *root)
11206 {
11207 if (atomic_read(&root->will_be_snapshoted))
11208 return 0;
11209
11210 percpu_counter_inc(&root->subv_writers->counter);
11211 /*
11212 * Make sure counter is updated before we check for snapshot creation.
11213 */
11214 smp_mb();
11215 if (atomic_read(&root->will_be_snapshoted)) {
11216 btrfs_end_write_no_snapshoting(root);
11217 return 0;
11218 }
11219 return 1;
11220 }
11221
11222 static int wait_snapshoting_atomic_t(atomic_t *a)
11223 {
11224 schedule();
11225 return 0;
11226 }
11227
11228 void btrfs_wait_for_snapshot_creation(struct btrfs_root *root)
11229 {
11230 while (true) {
11231 int ret;
11232
11233 ret = btrfs_start_write_no_snapshoting(root);
11234 if (ret)
11235 break;
11236 wait_on_atomic_t(&root->will_be_snapshoted,
11237 wait_snapshoting_atomic_t,
11238 TASK_UNINTERRUPTIBLE);
11239 }
11240 }
Linux with added FPC-III support