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ALSA: hda - Adding one more ALC255 pin definition for headset problem
[linux/fpc-iii.git] / fs / btrfs / extent-tree.c
blob61b494e8e604e9e80f1c46c581ede724f56ea050
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 /*
64 * Control how reservations are dealt with.
65 *
66 * RESERVE_FREE - freeing a reservation.
67 * RESERVE_ALLOC - allocating space and we need to update bytes_may_use for
68 * ENOSPC accounting
69 * RESERVE_ALLOC_NO_ACCOUNT - allocating space and we should not update
70 * bytes_may_use as the ENOSPC accounting is done elsewhere
71 */
72 enum {
73 RESERVE_FREE = 0,
74 RESERVE_ALLOC = 1,
75 RESERVE_ALLOC_NO_ACCOUNT = 2,
76 };
77
78 static int update_block_group(struct btrfs_trans_handle *trans,
79 struct btrfs_root *root, u64 bytenr,
80 u64 num_bytes, int alloc);
81 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
82 struct btrfs_root *root,
83 struct btrfs_delayed_ref_node *node, u64 parent,
84 u64 root_objectid, u64 owner_objectid,
85 u64 owner_offset, int refs_to_drop,
86 struct btrfs_delayed_extent_op *extra_op);
87 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
88 struct extent_buffer *leaf,
89 struct btrfs_extent_item *ei);
90 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
91 struct btrfs_root *root,
92 u64 parent, u64 root_objectid,
93 u64 flags, u64 owner, u64 offset,
94 struct btrfs_key *ins, int ref_mod);
95 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
96 struct btrfs_root *root,
97 u64 parent, u64 root_objectid,
98 u64 flags, struct btrfs_disk_key *key,
99 int level, struct btrfs_key *ins);
100 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
101 struct btrfs_root *extent_root, u64 flags,
102 int force);
103 static int find_next_key(struct btrfs_path *path, int level,
104 struct btrfs_key *key);
105 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
106 int dump_block_groups);
107 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
108 u64 num_bytes, int reserve,
109 int delalloc);
110 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
111 u64 num_bytes);
112 int btrfs_pin_extent(struct btrfs_root *root,
113 u64 bytenr, u64 num_bytes, int reserved);
114 static int __reserve_metadata_bytes(struct btrfs_root *root,
115 struct btrfs_space_info *space_info,
116 u64 orig_bytes,
117 enum btrfs_reserve_flush_enum flush);
118 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
119 struct btrfs_space_info *space_info,
120 u64 num_bytes);
121 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
122 struct btrfs_space_info *space_info,
123 u64 num_bytes);
124
125 static noinline int
126 block_group_cache_done(struct btrfs_block_group_cache *cache)
127 {
128 smp_mb();
129 return cache->cached == BTRFS_CACHE_FINISHED ||
130 cache->cached == BTRFS_CACHE_ERROR;
131 }
132
133 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
134 {
135 return (cache->flags & bits) == bits;
136 }
137
138 void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
139 {
140 atomic_inc(&cache->count);
141 }
142
143 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
144 {
145 if (atomic_dec_and_test(&cache->count)) {
146 WARN_ON(cache->pinned > 0);
147 WARN_ON(cache->reserved > 0);
148 kfree(cache->free_space_ctl);
149 kfree(cache);
150 }
151 }
152
153 /*
154 * this adds the block group to the fs_info rb tree for the block group
155 * cache
156 */
157 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
158 struct btrfs_block_group_cache *block_group)
159 {
160 struct rb_node **p;
161 struct rb_node *parent = NULL;
162 struct btrfs_block_group_cache *cache;
163
164 spin_lock(&info->block_group_cache_lock);
165 p = &info->block_group_cache_tree.rb_node;
166
167 while (*p) {
168 parent = *p;
169 cache = rb_entry(parent, struct btrfs_block_group_cache,
170 cache_node);
171 if (block_group->key.objectid < cache->key.objectid) {
172 p = &(*p)->rb_left;
173 } else if (block_group->key.objectid > cache->key.objectid) {
174 p = &(*p)->rb_right;
175 } else {
176 spin_unlock(&info->block_group_cache_lock);
177 return -EEXIST;
178 }
179 }
180
181 rb_link_node(&block_group->cache_node, parent, p);
182 rb_insert_color(&block_group->cache_node,
183 &info->block_group_cache_tree);
184
185 if (info->first_logical_byte > block_group->key.objectid)
186 info->first_logical_byte = block_group->key.objectid;
187
188 spin_unlock(&info->block_group_cache_lock);
189
190 return 0;
191 }
192
193 /*
194 * This will return the block group at or after bytenr if contains is 0, else
195 * it will return the block group that contains the bytenr
196 */
197 static struct btrfs_block_group_cache *
198 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
199 int contains)
200 {
201 struct btrfs_block_group_cache *cache, *ret = NULL;
202 struct rb_node *n;
203 u64 end, start;
204
205 spin_lock(&info->block_group_cache_lock);
206 n = info->block_group_cache_tree.rb_node;
207
208 while (n) {
209 cache = rb_entry(n, struct btrfs_block_group_cache,
210 cache_node);
211 end = cache->key.objectid + cache->key.offset - 1;
212 start = cache->key.objectid;
213
214 if (bytenr < start) {
215 if (!contains && (!ret || start < ret->key.objectid))
216 ret = cache;
217 n = n->rb_left;
218 } else if (bytenr > start) {
219 if (contains && bytenr <= end) {
220 ret = cache;
221 break;
222 }
223 n = n->rb_right;
224 } else {
225 ret = cache;
226 break;
227 }
228 }
229 if (ret) {
230 btrfs_get_block_group(ret);
231 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
232 info->first_logical_byte = ret->key.objectid;
233 }
234 spin_unlock(&info->block_group_cache_lock);
235
236 return ret;
237 }
238
239 static int add_excluded_extent(struct btrfs_root *root,
240 u64 start, u64 num_bytes)
241 {
242 u64 end = start + num_bytes - 1;
243 set_extent_bits(&root->fs_info->freed_extents[0],
244 start, end, EXTENT_UPTODATE);
245 set_extent_bits(&root->fs_info->freed_extents[1],
246 start, end, EXTENT_UPTODATE);
247 return 0;
248 }
249
250 static void free_excluded_extents(struct btrfs_root *root,
251 struct btrfs_block_group_cache *cache)
252 {
253 u64 start, end;
254
255 start = cache->key.objectid;
256 end = start + cache->key.offset - 1;
257
258 clear_extent_bits(&root->fs_info->freed_extents[0],
259 start, end, EXTENT_UPTODATE);
260 clear_extent_bits(&root->fs_info->freed_extents[1],
261 start, end, EXTENT_UPTODATE);
262 }
263
264 static int exclude_super_stripes(struct btrfs_root *root,
265 struct btrfs_block_group_cache *cache)
266 {
267 u64 bytenr;
268 u64 *logical;
269 int stripe_len;
270 int i, nr, ret;
271
272 if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
273 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
274 cache->bytes_super += stripe_len;
275 ret = add_excluded_extent(root, cache->key.objectid,
276 stripe_len);
277 if (ret)
278 return ret;
279 }
280
281 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
282 bytenr = btrfs_sb_offset(i);
283 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
284 cache->key.objectid, bytenr,
285 0, &logical, &nr, &stripe_len);
286 if (ret)
287 return ret;
288
289 while (nr--) {
290 u64 start, len;
291
292 if (logical[nr] > cache->key.objectid +
293 cache->key.offset)
294 continue;
295
296 if (logical[nr] + stripe_len <= cache->key.objectid)
297 continue;
298
299 start = logical[nr];
300 if (start < cache->key.objectid) {
301 start = cache->key.objectid;
302 len = (logical[nr] + stripe_len) - start;
303 } else {
304 len = min_t(u64, stripe_len,
305 cache->key.objectid +
306 cache->key.offset - start);
307 }
308
309 cache->bytes_super += len;
310 ret = add_excluded_extent(root, start, len);
311 if (ret) {
312 kfree(logical);
313 return ret;
314 }
315 }
316
317 kfree(logical);
318 }
319 return 0;
320 }
321
322 static struct btrfs_caching_control *
323 get_caching_control(struct btrfs_block_group_cache *cache)
324 {
325 struct btrfs_caching_control *ctl;
326
327 spin_lock(&cache->lock);
328 if (!cache->caching_ctl) {
329 spin_unlock(&cache->lock);
330 return NULL;
331 }
332
333 ctl = cache->caching_ctl;
334 atomic_inc(&ctl->count);
335 spin_unlock(&cache->lock);
336 return ctl;
337 }
338
339 static void put_caching_control(struct btrfs_caching_control *ctl)
340 {
341 if (atomic_dec_and_test(&ctl->count))
342 kfree(ctl);
343 }
344
345 #ifdef CONFIG_BTRFS_DEBUG
346 static void fragment_free_space(struct btrfs_root *root,
347 struct btrfs_block_group_cache *block_group)
348 {
349 u64 start = block_group->key.objectid;
350 u64 len = block_group->key.offset;
351 u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ?
352 root->nodesize : root->sectorsize;
353 u64 step = chunk << 1;
354
355 while (len > chunk) {
356 btrfs_remove_free_space(block_group, start, chunk);
357 start += step;
358 if (len < step)
359 len = 0;
360 else
361 len -= step;
362 }
363 }
364 #endif
365
366 /*
367 * this is only called by cache_block_group, since we could have freed extents
368 * we need to check the pinned_extents for any extents that can't be used yet
369 * since their free space will be released as soon as the transaction commits.
370 */
371 u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
372 struct btrfs_fs_info *info, u64 start, u64 end)
373 {
374 u64 extent_start, extent_end, size, total_added = 0;
375 int ret;
376
377 while (start < end) {
378 ret = find_first_extent_bit(info->pinned_extents, start,
379 &extent_start, &extent_end,
380 EXTENT_DIRTY | EXTENT_UPTODATE,
381 NULL);
382 if (ret)
383 break;
384
385 if (extent_start <= start) {
386 start = extent_end + 1;
387 } else if (extent_start > start && extent_start < end) {
388 size = extent_start - start;
389 total_added += size;
390 ret = btrfs_add_free_space(block_group, start,
391 size);
392 BUG_ON(ret); /* -ENOMEM or logic error */
393 start = extent_end + 1;
394 } else {
395 break;
396 }
397 }
398
399 if (start < end) {
400 size = end - start;
401 total_added += size;
402 ret = btrfs_add_free_space(block_group, start, size);
403 BUG_ON(ret); /* -ENOMEM or logic error */
404 }
405
406 return total_added;
407 }
408
409 static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl)
410 {
411 struct btrfs_block_group_cache *block_group;
412 struct btrfs_fs_info *fs_info;
413 struct btrfs_root *extent_root;
414 struct btrfs_path *path;
415 struct extent_buffer *leaf;
416 struct btrfs_key key;
417 u64 total_found = 0;
418 u64 last = 0;
419 u32 nritems;
420 int ret;
421 bool wakeup = true;
422
423 block_group = caching_ctl->block_group;
424 fs_info = block_group->fs_info;
425 extent_root = fs_info->extent_root;
426
427 path = btrfs_alloc_path();
428 if (!path)
429 return -ENOMEM;
430
431 last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
432
433 #ifdef CONFIG_BTRFS_DEBUG
434 /*
435 * If we're fragmenting we don't want to make anybody think we can
436 * allocate from this block group until we've had a chance to fragment
437 * the free space.
438 */
439 if (btrfs_should_fragment_free_space(extent_root, block_group))
440 wakeup = false;
441 #endif
442 /*
443 * We don't want to deadlock with somebody trying to allocate a new
444 * extent for the extent root while also trying to search the extent
445 * root to add free space. So we skip locking and search the commit
446 * root, since its read-only
447 */
448 path->skip_locking = 1;
449 path->search_commit_root = 1;
450 path->reada = READA_FORWARD;
451
452 key.objectid = last;
453 key.offset = 0;
454 key.type = BTRFS_EXTENT_ITEM_KEY;
455
456 next:
457 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
458 if (ret < 0)
459 goto out;
460
461 leaf = path->nodes[0];
462 nritems = btrfs_header_nritems(leaf);
463
464 while (1) {
465 if (btrfs_fs_closing(fs_info) > 1) {
466 last = (u64)-1;
467 break;
468 }
469
470 if (path->slots[0] < nritems) {
471 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
472 } else {
473 ret = find_next_key(path, 0, &key);
474 if (ret)
475 break;
476
477 if (need_resched() ||
478 rwsem_is_contended(&fs_info->commit_root_sem)) {
479 if (wakeup)
480 caching_ctl->progress = last;
481 btrfs_release_path(path);
482 up_read(&fs_info->commit_root_sem);
483 mutex_unlock(&caching_ctl->mutex);
484 cond_resched();
485 mutex_lock(&caching_ctl->mutex);
486 down_read(&fs_info->commit_root_sem);
487 goto next;
488 }
489
490 ret = btrfs_next_leaf(extent_root, path);
491 if (ret < 0)
492 goto out;
493 if (ret)
494 break;
495 leaf = path->nodes[0];
496 nritems = btrfs_header_nritems(leaf);
497 continue;
498 }
499
500 if (key.objectid < last) {
501 key.objectid = last;
502 key.offset = 0;
503 key.type = BTRFS_EXTENT_ITEM_KEY;
504
505 if (wakeup)
506 caching_ctl->progress = last;
507 btrfs_release_path(path);
508 goto next;
509 }
510
511 if (key.objectid < block_group->key.objectid) {
512 path->slots[0]++;
513 continue;
514 }
515
516 if (key.objectid >= block_group->key.objectid +
517 block_group->key.offset)
518 break;
519
520 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
521 key.type == BTRFS_METADATA_ITEM_KEY) {
522 total_found += add_new_free_space(block_group,
523 fs_info, last,
524 key.objectid);
525 if (key.type == BTRFS_METADATA_ITEM_KEY)
526 last = key.objectid +
527 fs_info->tree_root->nodesize;
528 else
529 last = key.objectid + key.offset;
530
531 if (total_found > CACHING_CTL_WAKE_UP) {
532 total_found = 0;
533 if (wakeup)
534 wake_up(&caching_ctl->wait);
535 }
536 }
537 path->slots[0]++;
538 }
539 ret = 0;
540
541 total_found += add_new_free_space(block_group, fs_info, last,
542 block_group->key.objectid +
543 block_group->key.offset);
544 caching_ctl->progress = (u64)-1;
545
546 out:
547 btrfs_free_path(path);
548 return ret;
549 }
550
551 static noinline void caching_thread(struct btrfs_work *work)
552 {
553 struct btrfs_block_group_cache *block_group;
554 struct btrfs_fs_info *fs_info;
555 struct btrfs_caching_control *caching_ctl;
556 struct btrfs_root *extent_root;
557 int ret;
558
559 caching_ctl = container_of(work, struct btrfs_caching_control, work);
560 block_group = caching_ctl->block_group;
561 fs_info = block_group->fs_info;
562 extent_root = fs_info->extent_root;
563
564 mutex_lock(&caching_ctl->mutex);
565 down_read(&fs_info->commit_root_sem);
566
567 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
568 ret = load_free_space_tree(caching_ctl);
569 else
570 ret = load_extent_tree_free(caching_ctl);
571
572 spin_lock(&block_group->lock);
573 block_group->caching_ctl = NULL;
574 block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED;
575 spin_unlock(&block_group->lock);
576
577 #ifdef CONFIG_BTRFS_DEBUG
578 if (btrfs_should_fragment_free_space(extent_root, block_group)) {
579 u64 bytes_used;
580
581 spin_lock(&block_group->space_info->lock);
582 spin_lock(&block_group->lock);
583 bytes_used = block_group->key.offset -
584 btrfs_block_group_used(&block_group->item);
585 block_group->space_info->bytes_used += bytes_used >> 1;
586 spin_unlock(&block_group->lock);
587 spin_unlock(&block_group->space_info->lock);
588 fragment_free_space(extent_root, block_group);
589 }
590 #endif
591
592 caching_ctl->progress = (u64)-1;
593
594 up_read(&fs_info->commit_root_sem);
595 free_excluded_extents(fs_info->extent_root, block_group);
596 mutex_unlock(&caching_ctl->mutex);
597
598 wake_up(&caching_ctl->wait);
599
600 put_caching_control(caching_ctl);
601 btrfs_put_block_group(block_group);
602 }
603
604 static int cache_block_group(struct btrfs_block_group_cache *cache,
605 int load_cache_only)
606 {
607 DEFINE_WAIT(wait);
608 struct btrfs_fs_info *fs_info = cache->fs_info;
609 struct btrfs_caching_control *caching_ctl;
610 int ret = 0;
611
612 caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
613 if (!caching_ctl)
614 return -ENOMEM;
615
616 INIT_LIST_HEAD(&caching_ctl->list);
617 mutex_init(&caching_ctl->mutex);
618 init_waitqueue_head(&caching_ctl->wait);
619 caching_ctl->block_group = cache;
620 caching_ctl->progress = cache->key.objectid;
621 atomic_set(&caching_ctl->count, 1);
622 btrfs_init_work(&caching_ctl->work, btrfs_cache_helper,
623 caching_thread, NULL, NULL);
624
625 spin_lock(&cache->lock);
626 /*
627 * This should be a rare occasion, but this could happen I think in the
628 * case where one thread starts to load the space cache info, and then
629 * some other thread starts a transaction commit which tries to do an
630 * allocation while the other thread is still loading the space cache
631 * info. The previous loop should have kept us from choosing this block
632 * group, but if we've moved to the state where we will wait on caching
633 * block groups we need to first check if we're doing a fast load here,
634 * so we can wait for it to finish, otherwise we could end up allocating
635 * from a block group who's cache gets evicted for one reason or
636 * another.
637 */
638 while (cache->cached == BTRFS_CACHE_FAST) {
639 struct btrfs_caching_control *ctl;
640
641 ctl = cache->caching_ctl;
642 atomic_inc(&ctl->count);
643 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
644 spin_unlock(&cache->lock);
645
646 schedule();
647
648 finish_wait(&ctl->wait, &wait);
649 put_caching_control(ctl);
650 spin_lock(&cache->lock);
651 }
652
653 if (cache->cached != BTRFS_CACHE_NO) {
654 spin_unlock(&cache->lock);
655 kfree(caching_ctl);
656 return 0;
657 }
658 WARN_ON(cache->caching_ctl);
659 cache->caching_ctl = caching_ctl;
660 cache->cached = BTRFS_CACHE_FAST;
661 spin_unlock(&cache->lock);
662
663 if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
664 mutex_lock(&caching_ctl->mutex);
665 ret = load_free_space_cache(fs_info, cache);
666
667 spin_lock(&cache->lock);
668 if (ret == 1) {
669 cache->caching_ctl = NULL;
670 cache->cached = BTRFS_CACHE_FINISHED;
671 cache->last_byte_to_unpin = (u64)-1;
672 caching_ctl->progress = (u64)-1;
673 } else {
674 if (load_cache_only) {
675 cache->caching_ctl = NULL;
676 cache->cached = BTRFS_CACHE_NO;
677 } else {
678 cache->cached = BTRFS_CACHE_STARTED;
679 cache->has_caching_ctl = 1;
680 }
681 }
682 spin_unlock(&cache->lock);
683 #ifdef CONFIG_BTRFS_DEBUG
684 if (ret == 1 &&
685 btrfs_should_fragment_free_space(fs_info->extent_root,
686 cache)) {
687 u64 bytes_used;
688
689 spin_lock(&cache->space_info->lock);
690 spin_lock(&cache->lock);
691 bytes_used = cache->key.offset -
692 btrfs_block_group_used(&cache->item);
693 cache->space_info->bytes_used += bytes_used >> 1;
694 spin_unlock(&cache->lock);
695 spin_unlock(&cache->space_info->lock);
696 fragment_free_space(fs_info->extent_root, cache);
697 }
698 #endif
699 mutex_unlock(&caching_ctl->mutex);
700
701 wake_up(&caching_ctl->wait);
702 if (ret == 1) {
703 put_caching_control(caching_ctl);
704 free_excluded_extents(fs_info->extent_root, cache);
705 return 0;
706 }
707 } else {
708 /*
709 * We're either using the free space tree or no caching at all.
710 * Set cached to the appropriate value and wakeup any waiters.
711 */
712 spin_lock(&cache->lock);
713 if (load_cache_only) {
714 cache->caching_ctl = NULL;
715 cache->cached = BTRFS_CACHE_NO;
716 } else {
717 cache->cached = BTRFS_CACHE_STARTED;
718 cache->has_caching_ctl = 1;
719 }
720 spin_unlock(&cache->lock);
721 wake_up(&caching_ctl->wait);
722 }
723
724 if (load_cache_only) {
725 put_caching_control(caching_ctl);
726 return 0;
727 }
728
729 down_write(&fs_info->commit_root_sem);
730 atomic_inc(&caching_ctl->count);
731 list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
732 up_write(&fs_info->commit_root_sem);
733
734 btrfs_get_block_group(cache);
735
736 btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
737
738 return ret;
739 }
740
741 /*
742 * return the block group that starts at or after bytenr
743 */
744 static struct btrfs_block_group_cache *
745 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
746 {
747 struct btrfs_block_group_cache *cache;
748
749 cache = block_group_cache_tree_search(info, bytenr, 0);
750
751 return cache;
752 }
753
754 /*
755 * return the block group that contains the given bytenr
756 */
757 struct btrfs_block_group_cache *btrfs_lookup_block_group(
758 struct btrfs_fs_info *info,
759 u64 bytenr)
760 {
761 struct btrfs_block_group_cache *cache;
762
763 cache = block_group_cache_tree_search(info, bytenr, 1);
764
765 return cache;
766 }
767
768 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
769 u64 flags)
770 {
771 struct list_head *head = &info->space_info;
772 struct btrfs_space_info *found;
773
774 flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
775
776 rcu_read_lock();
777 list_for_each_entry_rcu(found, head, list) {
778 if (found->flags & flags) {
779 rcu_read_unlock();
780 return found;
781 }
782 }
783 rcu_read_unlock();
784 return NULL;
785 }
786
787 /*
788 * after adding space to the filesystem, we need to clear the full flags
789 * on all the space infos.
790 */
791 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
792 {
793 struct list_head *head = &info->space_info;
794 struct btrfs_space_info *found;
795
796 rcu_read_lock();
797 list_for_each_entry_rcu(found, head, list)
798 found->full = 0;
799 rcu_read_unlock();
800 }
801
802 /* simple helper to search for an existing data extent at a given offset */
803 int btrfs_lookup_data_extent(struct btrfs_root *root, u64 start, u64 len)
804 {
805 int ret;
806 struct btrfs_key key;
807 struct btrfs_path *path;
808
809 path = btrfs_alloc_path();
810 if (!path)
811 return -ENOMEM;
812
813 key.objectid = start;
814 key.offset = len;
815 key.type = BTRFS_EXTENT_ITEM_KEY;
816 ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
817 0, 0);
818 btrfs_free_path(path);
819 return ret;
820 }
821
822 /*
823 * helper function to lookup reference count and flags of a tree block.
824 *
825 * the head node for delayed ref is used to store the sum of all the
826 * reference count modifications queued up in the rbtree. the head
827 * node may also store the extent flags to set. This way you can check
828 * to see what the reference count and extent flags would be if all of
829 * the delayed refs are not processed.
830 */
831 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
832 struct btrfs_root *root, u64 bytenr,
833 u64 offset, int metadata, u64 *refs, u64 *flags)
834 {
835 struct btrfs_delayed_ref_head *head;
836 struct btrfs_delayed_ref_root *delayed_refs;
837 struct btrfs_path *path;
838 struct btrfs_extent_item *ei;
839 struct extent_buffer *leaf;
840 struct btrfs_key key;
841 u32 item_size;
842 u64 num_refs;
843 u64 extent_flags;
844 int ret;
845
846 /*
847 * If we don't have skinny metadata, don't bother doing anything
848 * different
849 */
850 if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA)) {
851 offset = root->nodesize;
852 metadata = 0;
853 }
854
855 path = btrfs_alloc_path();
856 if (!path)
857 return -ENOMEM;
858
859 if (!trans) {
860 path->skip_locking = 1;
861 path->search_commit_root = 1;
862 }
863
864 search_again:
865 key.objectid = bytenr;
866 key.offset = offset;
867 if (metadata)
868 key.type = BTRFS_METADATA_ITEM_KEY;
869 else
870 key.type = BTRFS_EXTENT_ITEM_KEY;
871
872 ret = btrfs_search_slot(trans, root->fs_info->extent_root,
873 &key, path, 0, 0);
874 if (ret < 0)
875 goto out_free;
876
877 if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
878 if (path->slots[0]) {
879 path->slots[0]--;
880 btrfs_item_key_to_cpu(path->nodes[0], &key,
881 path->slots[0]);
882 if (key.objectid == bytenr &&
883 key.type == BTRFS_EXTENT_ITEM_KEY &&
884 key.offset == root->nodesize)
885 ret = 0;
886 }
887 }
888
889 if (ret == 0) {
890 leaf = path->nodes[0];
891 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
892 if (item_size >= sizeof(*ei)) {
893 ei = btrfs_item_ptr(leaf, path->slots[0],
894 struct btrfs_extent_item);
895 num_refs = btrfs_extent_refs(leaf, ei);
896 extent_flags = btrfs_extent_flags(leaf, ei);
897 } else {
898 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
899 struct btrfs_extent_item_v0 *ei0;
900 BUG_ON(item_size != sizeof(*ei0));
901 ei0 = btrfs_item_ptr(leaf, path->slots[0],
902 struct btrfs_extent_item_v0);
903 num_refs = btrfs_extent_refs_v0(leaf, ei0);
904 /* FIXME: this isn't correct for data */
905 extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
906 #else
907 BUG();
908 #endif
909 }
910 BUG_ON(num_refs == 0);
911 } else {
912 num_refs = 0;
913 extent_flags = 0;
914 ret = 0;
915 }
916
917 if (!trans)
918 goto out;
919
920 delayed_refs = &trans->transaction->delayed_refs;
921 spin_lock(&delayed_refs->lock);
922 head = btrfs_find_delayed_ref_head(trans, bytenr);
923 if (head) {
924 if (!mutex_trylock(&head->mutex)) {
925 atomic_inc(&head->node.refs);
926 spin_unlock(&delayed_refs->lock);
927
928 btrfs_release_path(path);
929
930 /*
931 * Mutex was contended, block until it's released and try
932 * again
933 */
934 mutex_lock(&head->mutex);
935 mutex_unlock(&head->mutex);
936 btrfs_put_delayed_ref(&head->node);
937 goto search_again;
938 }
939 spin_lock(&head->lock);
940 if (head->extent_op && head->extent_op->update_flags)
941 extent_flags |= head->extent_op->flags_to_set;
942 else
943 BUG_ON(num_refs == 0);
944
945 num_refs += head->node.ref_mod;
946 spin_unlock(&head->lock);
947 mutex_unlock(&head->mutex);
948 }
949 spin_unlock(&delayed_refs->lock);
950 out:
951 WARN_ON(num_refs == 0);
952 if (refs)
953 *refs = num_refs;
954 if (flags)
955 *flags = extent_flags;
956 out_free:
957 btrfs_free_path(path);
958 return ret;
959 }
960
961 /*
962 * Back reference rules. Back refs have three main goals:
963 *
964 * 1) differentiate between all holders of references to an extent so that
965 * when a reference is dropped we can make sure it was a valid reference
966 * before freeing the extent.
967 *
968 * 2) Provide enough information to quickly find the holders of an extent
969 * if we notice a given block is corrupted or bad.
970 *
971 * 3) Make it easy to migrate blocks for FS shrinking or storage pool
972 * maintenance. This is actually the same as #2, but with a slightly
973 * different use case.
974 *
975 * There are two kinds of back refs. The implicit back refs is optimized
976 * for pointers in non-shared tree blocks. For a given pointer in a block,
977 * back refs of this kind provide information about the block's owner tree
978 * and the pointer's key. These information allow us to find the block by
979 * b-tree searching. The full back refs is for pointers in tree blocks not
980 * referenced by their owner trees. The location of tree block is recorded
981 * in the back refs. Actually the full back refs is generic, and can be
982 * used in all cases the implicit back refs is used. The major shortcoming
983 * of the full back refs is its overhead. Every time a tree block gets
984 * COWed, we have to update back refs entry for all pointers in it.
985 *
986 * For a newly allocated tree block, we use implicit back refs for
987 * pointers in it. This means most tree related operations only involve
988 * implicit back refs. For a tree block created in old transaction, the
989 * only way to drop a reference to it is COW it. So we can detect the
990 * event that tree block loses its owner tree's reference and do the
991 * back refs conversion.
992 *
993 * When a tree block is COWed through a tree, there are four cases:
994 *
995 * The reference count of the block is one and the tree is the block's
996 * owner tree. Nothing to do in this case.
997 *
998 * The reference count of the block is one and the tree is not the
999 * block's owner tree. In this case, full back refs is used for pointers
1000 * in the block. Remove these full back refs, add implicit back refs for
1001 * every pointers in the new block.
1002 *
1003 * The reference count of the block is greater than one and the tree is
1004 * the block's owner tree. In this case, implicit back refs is used for
1005 * pointers in the block. Add full back refs for every pointers in the
1006 * block, increase lower level extents' reference counts. The original
1007 * implicit back refs are entailed to the new block.
1008 *
1009 * The reference count of the block is greater than one and the tree is
1010 * not the block's owner tree. Add implicit back refs for every pointer in
1011 * the new block, increase lower level extents' reference count.
1012 *
1013 * Back Reference Key composing:
1014 *
1015 * The key objectid corresponds to the first byte in the extent,
1016 * The key type is used to differentiate between types of back refs.
1017 * There are different meanings of the key offset for different types
1018 * of back refs.
1019 *
1020 * File extents can be referenced by:
1021 *
1022 * - multiple snapshots, subvolumes, or different generations in one subvol
1023 * - different files inside a single subvolume
1024 * - different offsets inside a file (bookend extents in file.c)
1025 *
1026 * The extent ref structure for the implicit back refs has fields for:
1027 *
1028 * - Objectid of the subvolume root
1029 * - objectid of the file holding the reference
1030 * - original offset in the file
1031 * - how many bookend extents
1032 *
1033 * The key offset for the implicit back refs is hash of the first
1034 * three fields.
1035 *
1036 * The extent ref structure for the full back refs has field for:
1037 *
1038 * - number of pointers in the tree leaf
1039 *
1040 * The key offset for the implicit back refs is the first byte of
1041 * the tree leaf
1042 *
1043 * When a file extent is allocated, The implicit back refs is used.
1044 * the fields are filled in:
1045 *
1046 * (root_key.objectid, inode objectid, offset in file, 1)
1047 *
1048 * When a file extent is removed file truncation, we find the
1049 * corresponding implicit back refs and check the following fields:
1050 *
1051 * (btrfs_header_owner(leaf), inode objectid, offset in file)
1052 *
1053 * Btree extents can be referenced by:
1054 *
1055 * - Different subvolumes
1056 *
1057 * Both the implicit back refs and the full back refs for tree blocks
1058 * only consist of key. The key offset for the implicit back refs is
1059 * objectid of block's owner tree. The key offset for the full back refs
1060 * is the first byte of parent block.
1061 *
1062 * When implicit back refs is used, information about the lowest key and
1063 * level of the tree block are required. These information are stored in
1064 * tree block info structure.
1065 */
1066
1067 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1068 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
1069 struct btrfs_root *root,
1070 struct btrfs_path *path,
1071 u64 owner, u32 extra_size)
1072 {
1073 struct btrfs_extent_item *item;
1074 struct btrfs_extent_item_v0 *ei0;
1075 struct btrfs_extent_ref_v0 *ref0;
1076 struct btrfs_tree_block_info *bi;
1077 struct extent_buffer *leaf;
1078 struct btrfs_key key;
1079 struct btrfs_key found_key;
1080 u32 new_size = sizeof(*item);
1081 u64 refs;
1082 int ret;
1083
1084 leaf = path->nodes[0];
1085 BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
1086
1087 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1088 ei0 = btrfs_item_ptr(leaf, path->slots[0],
1089 struct btrfs_extent_item_v0);
1090 refs = btrfs_extent_refs_v0(leaf, ei0);
1091
1092 if (owner == (u64)-1) {
1093 while (1) {
1094 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1095 ret = btrfs_next_leaf(root, path);
1096 if (ret < 0)
1097 return ret;
1098 BUG_ON(ret > 0); /* Corruption */
1099 leaf = path->nodes[0];
1100 }
1101 btrfs_item_key_to_cpu(leaf, &found_key,
1102 path->slots[0]);
1103 BUG_ON(key.objectid != found_key.objectid);
1104 if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
1105 path->slots[0]++;
1106 continue;
1107 }
1108 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1109 struct btrfs_extent_ref_v0);
1110 owner = btrfs_ref_objectid_v0(leaf, ref0);
1111 break;
1112 }
1113 }
1114 btrfs_release_path(path);
1115
1116 if (owner < BTRFS_FIRST_FREE_OBJECTID)
1117 new_size += sizeof(*bi);
1118
1119 new_size -= sizeof(*ei0);
1120 ret = btrfs_search_slot(trans, root, &key, path,
1121 new_size + extra_size, 1);
1122 if (ret < 0)
1123 return ret;
1124 BUG_ON(ret); /* Corruption */
1125
1126 btrfs_extend_item(root, path, new_size);
1127
1128 leaf = path->nodes[0];
1129 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1130 btrfs_set_extent_refs(leaf, item, refs);
1131 /* FIXME: get real generation */
1132 btrfs_set_extent_generation(leaf, item, 0);
1133 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1134 btrfs_set_extent_flags(leaf, item,
1135 BTRFS_EXTENT_FLAG_TREE_BLOCK |
1136 BTRFS_BLOCK_FLAG_FULL_BACKREF);
1137 bi = (struct btrfs_tree_block_info *)(item + 1);
1138 /* FIXME: get first key of the block */
1139 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1140 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1141 } else {
1142 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1143 }
1144 btrfs_mark_buffer_dirty(leaf);
1145 return 0;
1146 }
1147 #endif
1148
1149 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1150 {
1151 u32 high_crc = ~(u32)0;
1152 u32 low_crc = ~(u32)0;
1153 __le64 lenum;
1154
1155 lenum = cpu_to_le64(root_objectid);
1156 high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
1157 lenum = cpu_to_le64(owner);
1158 low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1159 lenum = cpu_to_le64(offset);
1160 low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1161
1162 return ((u64)high_crc << 31) ^ (u64)low_crc;
1163 }
1164
1165 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1166 struct btrfs_extent_data_ref *ref)
1167 {
1168 return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1169 btrfs_extent_data_ref_objectid(leaf, ref),
1170 btrfs_extent_data_ref_offset(leaf, ref));
1171 }
1172
1173 static int match_extent_data_ref(struct extent_buffer *leaf,
1174 struct btrfs_extent_data_ref *ref,
1175 u64 root_objectid, u64 owner, u64 offset)
1176 {
1177 if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1178 btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1179 btrfs_extent_data_ref_offset(leaf, ref) != offset)
1180 return 0;
1181 return 1;
1182 }
1183
1184 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1185 struct btrfs_root *root,
1186 struct btrfs_path *path,
1187 u64 bytenr, u64 parent,
1188 u64 root_objectid,
1189 u64 owner, u64 offset)
1190 {
1191 struct btrfs_key key;
1192 struct btrfs_extent_data_ref *ref;
1193 struct extent_buffer *leaf;
1194 u32 nritems;
1195 int ret;
1196 int recow;
1197 int err = -ENOENT;
1198
1199 key.objectid = bytenr;
1200 if (parent) {
1201 key.type = BTRFS_SHARED_DATA_REF_KEY;
1202 key.offset = parent;
1203 } else {
1204 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1205 key.offset = hash_extent_data_ref(root_objectid,
1206 owner, offset);
1207 }
1208 again:
1209 recow = 0;
1210 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1211 if (ret < 0) {
1212 err = ret;
1213 goto fail;
1214 }
1215
1216 if (parent) {
1217 if (!ret)
1218 return 0;
1219 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1220 key.type = BTRFS_EXTENT_REF_V0_KEY;
1221 btrfs_release_path(path);
1222 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1223 if (ret < 0) {
1224 err = ret;
1225 goto fail;
1226 }
1227 if (!ret)
1228 return 0;
1229 #endif
1230 goto fail;
1231 }
1232
1233 leaf = path->nodes[0];
1234 nritems = btrfs_header_nritems(leaf);
1235 while (1) {
1236 if (path->slots[0] >= nritems) {
1237 ret = btrfs_next_leaf(root, path);
1238 if (ret < 0)
1239 err = ret;
1240 if (ret)
1241 goto fail;
1242
1243 leaf = path->nodes[0];
1244 nritems = btrfs_header_nritems(leaf);
1245 recow = 1;
1246 }
1247
1248 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1249 if (key.objectid != bytenr ||
1250 key.type != BTRFS_EXTENT_DATA_REF_KEY)
1251 goto fail;
1252
1253 ref = btrfs_item_ptr(leaf, path->slots[0],
1254 struct btrfs_extent_data_ref);
1255
1256 if (match_extent_data_ref(leaf, ref, root_objectid,
1257 owner, offset)) {
1258 if (recow) {
1259 btrfs_release_path(path);
1260 goto again;
1261 }
1262 err = 0;
1263 break;
1264 }
1265 path->slots[0]++;
1266 }
1267 fail:
1268 return err;
1269 }
1270
1271 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1272 struct btrfs_root *root,
1273 struct btrfs_path *path,
1274 u64 bytenr, u64 parent,
1275 u64 root_objectid, u64 owner,
1276 u64 offset, int refs_to_add)
1277 {
1278 struct btrfs_key key;
1279 struct extent_buffer *leaf;
1280 u32 size;
1281 u32 num_refs;
1282 int ret;
1283
1284 key.objectid = bytenr;
1285 if (parent) {
1286 key.type = BTRFS_SHARED_DATA_REF_KEY;
1287 key.offset = parent;
1288 size = sizeof(struct btrfs_shared_data_ref);
1289 } else {
1290 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1291 key.offset = hash_extent_data_ref(root_objectid,
1292 owner, offset);
1293 size = sizeof(struct btrfs_extent_data_ref);
1294 }
1295
1296 ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1297 if (ret && ret != -EEXIST)
1298 goto fail;
1299
1300 leaf = path->nodes[0];
1301 if (parent) {
1302 struct btrfs_shared_data_ref *ref;
1303 ref = btrfs_item_ptr(leaf, path->slots[0],
1304 struct btrfs_shared_data_ref);
1305 if (ret == 0) {
1306 btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1307 } else {
1308 num_refs = btrfs_shared_data_ref_count(leaf, ref);
1309 num_refs += refs_to_add;
1310 btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1311 }
1312 } else {
1313 struct btrfs_extent_data_ref *ref;
1314 while (ret == -EEXIST) {
1315 ref = btrfs_item_ptr(leaf, path->slots[0],
1316 struct btrfs_extent_data_ref);
1317 if (match_extent_data_ref(leaf, ref, root_objectid,
1318 owner, offset))
1319 break;
1320 btrfs_release_path(path);
1321 key.offset++;
1322 ret = btrfs_insert_empty_item(trans, root, path, &key,
1323 size);
1324 if (ret && ret != -EEXIST)
1325 goto fail;
1326
1327 leaf = path->nodes[0];
1328 }
1329 ref = btrfs_item_ptr(leaf, path->slots[0],
1330 struct btrfs_extent_data_ref);
1331 if (ret == 0) {
1332 btrfs_set_extent_data_ref_root(leaf, ref,
1333 root_objectid);
1334 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1335 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1336 btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1337 } else {
1338 num_refs = btrfs_extent_data_ref_count(leaf, ref);
1339 num_refs += refs_to_add;
1340 btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1341 }
1342 }
1343 btrfs_mark_buffer_dirty(leaf);
1344 ret = 0;
1345 fail:
1346 btrfs_release_path(path);
1347 return ret;
1348 }
1349
1350 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1351 struct btrfs_root *root,
1352 struct btrfs_path *path,
1353 int refs_to_drop, int *last_ref)
1354 {
1355 struct btrfs_key key;
1356 struct btrfs_extent_data_ref *ref1 = NULL;
1357 struct btrfs_shared_data_ref *ref2 = NULL;
1358 struct extent_buffer *leaf;
1359 u32 num_refs = 0;
1360 int ret = 0;
1361
1362 leaf = path->nodes[0];
1363 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1364
1365 if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1366 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1367 struct btrfs_extent_data_ref);
1368 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1369 } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1370 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1371 struct btrfs_shared_data_ref);
1372 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1373 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1374 } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1375 struct btrfs_extent_ref_v0 *ref0;
1376 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1377 struct btrfs_extent_ref_v0);
1378 num_refs = btrfs_ref_count_v0(leaf, ref0);
1379 #endif
1380 } else {
1381 BUG();
1382 }
1383
1384 BUG_ON(num_refs < refs_to_drop);
1385 num_refs -= refs_to_drop;
1386
1387 if (num_refs == 0) {
1388 ret = btrfs_del_item(trans, root, path);
1389 *last_ref = 1;
1390 } else {
1391 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1392 btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1393 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1394 btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1395 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1396 else {
1397 struct btrfs_extent_ref_v0 *ref0;
1398 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1399 struct btrfs_extent_ref_v0);
1400 btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1401 }
1402 #endif
1403 btrfs_mark_buffer_dirty(leaf);
1404 }
1405 return ret;
1406 }
1407
1408 static noinline u32 extent_data_ref_count(struct btrfs_path *path,
1409 struct btrfs_extent_inline_ref *iref)
1410 {
1411 struct btrfs_key key;
1412 struct extent_buffer *leaf;
1413 struct btrfs_extent_data_ref *ref1;
1414 struct btrfs_shared_data_ref *ref2;
1415 u32 num_refs = 0;
1416
1417 leaf = path->nodes[0];
1418 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1419 if (iref) {
1420 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1421 BTRFS_EXTENT_DATA_REF_KEY) {
1422 ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1423 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1424 } else {
1425 ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1426 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1427 }
1428 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1429 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1430 struct btrfs_extent_data_ref);
1431 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1432 } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1433 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1434 struct btrfs_shared_data_ref);
1435 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1436 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1437 } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1438 struct btrfs_extent_ref_v0 *ref0;
1439 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1440 struct btrfs_extent_ref_v0);
1441 num_refs = btrfs_ref_count_v0(leaf, ref0);
1442 #endif
1443 } else {
1444 WARN_ON(1);
1445 }
1446 return num_refs;
1447 }
1448
1449 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1450 struct btrfs_root *root,
1451 struct btrfs_path *path,
1452 u64 bytenr, u64 parent,
1453 u64 root_objectid)
1454 {
1455 struct btrfs_key key;
1456 int ret;
1457
1458 key.objectid = bytenr;
1459 if (parent) {
1460 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1461 key.offset = parent;
1462 } else {
1463 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1464 key.offset = root_objectid;
1465 }
1466
1467 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1468 if (ret > 0)
1469 ret = -ENOENT;
1470 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1471 if (ret == -ENOENT && parent) {
1472 btrfs_release_path(path);
1473 key.type = BTRFS_EXTENT_REF_V0_KEY;
1474 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1475 if (ret > 0)
1476 ret = -ENOENT;
1477 }
1478 #endif
1479 return ret;
1480 }
1481
1482 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1483 struct btrfs_root *root,
1484 struct btrfs_path *path,
1485 u64 bytenr, u64 parent,
1486 u64 root_objectid)
1487 {
1488 struct btrfs_key key;
1489 int ret;
1490
1491 key.objectid = bytenr;
1492 if (parent) {
1493 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1494 key.offset = parent;
1495 } else {
1496 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1497 key.offset = root_objectid;
1498 }
1499
1500 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1501 btrfs_release_path(path);
1502 return ret;
1503 }
1504
1505 static inline int extent_ref_type(u64 parent, u64 owner)
1506 {
1507 int type;
1508 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1509 if (parent > 0)
1510 type = BTRFS_SHARED_BLOCK_REF_KEY;
1511 else
1512 type = BTRFS_TREE_BLOCK_REF_KEY;
1513 } else {
1514 if (parent > 0)
1515 type = BTRFS_SHARED_DATA_REF_KEY;
1516 else
1517 type = BTRFS_EXTENT_DATA_REF_KEY;
1518 }
1519 return type;
1520 }
1521
1522 static int find_next_key(struct btrfs_path *path, int level,
1523 struct btrfs_key *key)
1524
1525 {
1526 for (; level < BTRFS_MAX_LEVEL; level++) {
1527 if (!path->nodes[level])
1528 break;
1529 if (path->slots[level] + 1 >=
1530 btrfs_header_nritems(path->nodes[level]))
1531 continue;
1532 if (level == 0)
1533 btrfs_item_key_to_cpu(path->nodes[level], key,
1534 path->slots[level] + 1);
1535 else
1536 btrfs_node_key_to_cpu(path->nodes[level], key,
1537 path->slots[level] + 1);
1538 return 0;
1539 }
1540 return 1;
1541 }
1542
1543 /*
1544 * look for inline back ref. if back ref is found, *ref_ret is set
1545 * to the address of inline back ref, and 0 is returned.
1546 *
1547 * if back ref isn't found, *ref_ret is set to the address where it
1548 * should be inserted, and -ENOENT is returned.
1549 *
1550 * if insert is true and there are too many inline back refs, the path
1551 * points to the extent item, and -EAGAIN is returned.
1552 *
1553 * NOTE: inline back refs are ordered in the same way that back ref
1554 * items in the tree are ordered.
1555 */
1556 static noinline_for_stack
1557 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1558 struct btrfs_root *root,
1559 struct btrfs_path *path,
1560 struct btrfs_extent_inline_ref **ref_ret,
1561 u64 bytenr, u64 num_bytes,
1562 u64 parent, u64 root_objectid,
1563 u64 owner, u64 offset, int insert)
1564 {
1565 struct btrfs_key key;
1566 struct extent_buffer *leaf;
1567 struct btrfs_extent_item *ei;
1568 struct btrfs_extent_inline_ref *iref;
1569 u64 flags;
1570 u64 item_size;
1571 unsigned long ptr;
1572 unsigned long end;
1573 int extra_size;
1574 int type;
1575 int want;
1576 int ret;
1577 int err = 0;
1578 bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
1579 SKINNY_METADATA);
1580
1581 key.objectid = bytenr;
1582 key.type = BTRFS_EXTENT_ITEM_KEY;
1583 key.offset = num_bytes;
1584
1585 want = extent_ref_type(parent, owner);
1586 if (insert) {
1587 extra_size = btrfs_extent_inline_ref_size(want);
1588 path->keep_locks = 1;
1589 } else
1590 extra_size = -1;
1591
1592 /*
1593 * Owner is our parent level, so we can just add one to get the level
1594 * for the block we are interested in.
1595 */
1596 if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1597 key.type = BTRFS_METADATA_ITEM_KEY;
1598 key.offset = owner;
1599 }
1600
1601 again:
1602 ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1603 if (ret < 0) {
1604 err = ret;
1605 goto out;
1606 }
1607
1608 /*
1609 * We may be a newly converted file system which still has the old fat
1610 * extent entries for metadata, so try and see if we have one of those.
1611 */
1612 if (ret > 0 && skinny_metadata) {
1613 skinny_metadata = false;
1614 if (path->slots[0]) {
1615 path->slots[0]--;
1616 btrfs_item_key_to_cpu(path->nodes[0], &key,
1617 path->slots[0]);
1618 if (key.objectid == bytenr &&
1619 key.type == BTRFS_EXTENT_ITEM_KEY &&
1620 key.offset == num_bytes)
1621 ret = 0;
1622 }
1623 if (ret) {
1624 key.objectid = bytenr;
1625 key.type = BTRFS_EXTENT_ITEM_KEY;
1626 key.offset = num_bytes;
1627 btrfs_release_path(path);
1628 goto again;
1629 }
1630 }
1631
1632 if (ret && !insert) {
1633 err = -ENOENT;
1634 goto out;
1635 } else if (WARN_ON(ret)) {
1636 err = -EIO;
1637 goto out;
1638 }
1639
1640 leaf = path->nodes[0];
1641 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1642 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1643 if (item_size < sizeof(*ei)) {
1644 if (!insert) {
1645 err = -ENOENT;
1646 goto out;
1647 }
1648 ret = convert_extent_item_v0(trans, root, path, owner,
1649 extra_size);
1650 if (ret < 0) {
1651 err = ret;
1652 goto out;
1653 }
1654 leaf = path->nodes[0];
1655 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1656 }
1657 #endif
1658 BUG_ON(item_size < sizeof(*ei));
1659
1660 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1661 flags = btrfs_extent_flags(leaf, ei);
1662
1663 ptr = (unsigned long)(ei + 1);
1664 end = (unsigned long)ei + item_size;
1665
1666 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1667 ptr += sizeof(struct btrfs_tree_block_info);
1668 BUG_ON(ptr > end);
1669 }
1670
1671 err = -ENOENT;
1672 while (1) {
1673 if (ptr >= end) {
1674 WARN_ON(ptr > end);
1675 break;
1676 }
1677 iref = (struct btrfs_extent_inline_ref *)ptr;
1678 type = btrfs_extent_inline_ref_type(leaf, iref);
1679 if (want < type)
1680 break;
1681 if (want > type) {
1682 ptr += btrfs_extent_inline_ref_size(type);
1683 continue;
1684 }
1685
1686 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1687 struct btrfs_extent_data_ref *dref;
1688 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1689 if (match_extent_data_ref(leaf, dref, root_objectid,
1690 owner, offset)) {
1691 err = 0;
1692 break;
1693 }
1694 if (hash_extent_data_ref_item(leaf, dref) <
1695 hash_extent_data_ref(root_objectid, owner, offset))
1696 break;
1697 } else {
1698 u64 ref_offset;
1699 ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1700 if (parent > 0) {
1701 if (parent == ref_offset) {
1702 err = 0;
1703 break;
1704 }
1705 if (ref_offset < parent)
1706 break;
1707 } else {
1708 if (root_objectid == ref_offset) {
1709 err = 0;
1710 break;
1711 }
1712 if (ref_offset < root_objectid)
1713 break;
1714 }
1715 }
1716 ptr += btrfs_extent_inline_ref_size(type);
1717 }
1718 if (err == -ENOENT && insert) {
1719 if (item_size + extra_size >=
1720 BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1721 err = -EAGAIN;
1722 goto out;
1723 }
1724 /*
1725 * To add new inline back ref, we have to make sure
1726 * there is no corresponding back ref item.
1727 * For simplicity, we just do not add new inline back
1728 * ref if there is any kind of item for this block
1729 */
1730 if (find_next_key(path, 0, &key) == 0 &&
1731 key.objectid == bytenr &&
1732 key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1733 err = -EAGAIN;
1734 goto out;
1735 }
1736 }
1737 *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1738 out:
1739 if (insert) {
1740 path->keep_locks = 0;
1741 btrfs_unlock_up_safe(path, 1);
1742 }
1743 return err;
1744 }
1745
1746 /*
1747 * helper to add new inline back ref
1748 */
1749 static noinline_for_stack
1750 void setup_inline_extent_backref(struct btrfs_root *root,
1751 struct btrfs_path *path,
1752 struct btrfs_extent_inline_ref *iref,
1753 u64 parent, u64 root_objectid,
1754 u64 owner, u64 offset, int refs_to_add,
1755 struct btrfs_delayed_extent_op *extent_op)
1756 {
1757 struct extent_buffer *leaf;
1758 struct btrfs_extent_item *ei;
1759 unsigned long ptr;
1760 unsigned long end;
1761 unsigned long item_offset;
1762 u64 refs;
1763 int size;
1764 int type;
1765
1766 leaf = path->nodes[0];
1767 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1768 item_offset = (unsigned long)iref - (unsigned long)ei;
1769
1770 type = extent_ref_type(parent, owner);
1771 size = btrfs_extent_inline_ref_size(type);
1772
1773 btrfs_extend_item(root, path, size);
1774
1775 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1776 refs = btrfs_extent_refs(leaf, ei);
1777 refs += refs_to_add;
1778 btrfs_set_extent_refs(leaf, ei, refs);
1779 if (extent_op)
1780 __run_delayed_extent_op(extent_op, leaf, ei);
1781
1782 ptr = (unsigned long)ei + item_offset;
1783 end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1784 if (ptr < end - size)
1785 memmove_extent_buffer(leaf, ptr + size, ptr,
1786 end - size - ptr);
1787
1788 iref = (struct btrfs_extent_inline_ref *)ptr;
1789 btrfs_set_extent_inline_ref_type(leaf, iref, type);
1790 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1791 struct btrfs_extent_data_ref *dref;
1792 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1793 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1794 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1795 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1796 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1797 } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1798 struct btrfs_shared_data_ref *sref;
1799 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1800 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1801 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1802 } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1803 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1804 } else {
1805 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1806 }
1807 btrfs_mark_buffer_dirty(leaf);
1808 }
1809
1810 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1811 struct btrfs_root *root,
1812 struct btrfs_path *path,
1813 struct btrfs_extent_inline_ref **ref_ret,
1814 u64 bytenr, u64 num_bytes, u64 parent,
1815 u64 root_objectid, u64 owner, u64 offset)
1816 {
1817 int ret;
1818
1819 ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1820 bytenr, num_bytes, parent,
1821 root_objectid, owner, offset, 0);
1822 if (ret != -ENOENT)
1823 return ret;
1824
1825 btrfs_release_path(path);
1826 *ref_ret = NULL;
1827
1828 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1829 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1830 root_objectid);
1831 } else {
1832 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1833 root_objectid, owner, offset);
1834 }
1835 return ret;
1836 }
1837
1838 /*
1839 * helper to update/remove inline back ref
1840 */
1841 static noinline_for_stack
1842 void update_inline_extent_backref(struct btrfs_root *root,
1843 struct btrfs_path *path,
1844 struct btrfs_extent_inline_ref *iref,
1845 int refs_to_mod,
1846 struct btrfs_delayed_extent_op *extent_op,
1847 int *last_ref)
1848 {
1849 struct extent_buffer *leaf;
1850 struct btrfs_extent_item *ei;
1851 struct btrfs_extent_data_ref *dref = NULL;
1852 struct btrfs_shared_data_ref *sref = NULL;
1853 unsigned long ptr;
1854 unsigned long end;
1855 u32 item_size;
1856 int size;
1857 int type;
1858 u64 refs;
1859
1860 leaf = path->nodes[0];
1861 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1862 refs = btrfs_extent_refs(leaf, ei);
1863 WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1864 refs += refs_to_mod;
1865 btrfs_set_extent_refs(leaf, ei, refs);
1866 if (extent_op)
1867 __run_delayed_extent_op(extent_op, leaf, ei);
1868
1869 type = btrfs_extent_inline_ref_type(leaf, iref);
1870
1871 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1872 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1873 refs = btrfs_extent_data_ref_count(leaf, dref);
1874 } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1875 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1876 refs = btrfs_shared_data_ref_count(leaf, sref);
1877 } else {
1878 refs = 1;
1879 BUG_ON(refs_to_mod != -1);
1880 }
1881
1882 BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1883 refs += refs_to_mod;
1884
1885 if (refs > 0) {
1886 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1887 btrfs_set_extent_data_ref_count(leaf, dref, refs);
1888 else
1889 btrfs_set_shared_data_ref_count(leaf, sref, refs);
1890 } else {
1891 *last_ref = 1;
1892 size = btrfs_extent_inline_ref_size(type);
1893 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1894 ptr = (unsigned long)iref;
1895 end = (unsigned long)ei + item_size;
1896 if (ptr + size < end)
1897 memmove_extent_buffer(leaf, ptr, ptr + size,
1898 end - ptr - size);
1899 item_size -= size;
1900 btrfs_truncate_item(root, path, item_size, 1);
1901 }
1902 btrfs_mark_buffer_dirty(leaf);
1903 }
1904
1905 static noinline_for_stack
1906 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1907 struct btrfs_root *root,
1908 struct btrfs_path *path,
1909 u64 bytenr, u64 num_bytes, u64 parent,
1910 u64 root_objectid, u64 owner,
1911 u64 offset, int refs_to_add,
1912 struct btrfs_delayed_extent_op *extent_op)
1913 {
1914 struct btrfs_extent_inline_ref *iref;
1915 int ret;
1916
1917 ret = lookup_inline_extent_backref(trans, root, path, &iref,
1918 bytenr, num_bytes, parent,
1919 root_objectid, owner, offset, 1);
1920 if (ret == 0) {
1921 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1922 update_inline_extent_backref(root, path, iref,
1923 refs_to_add, extent_op, NULL);
1924 } else if (ret == -ENOENT) {
1925 setup_inline_extent_backref(root, path, iref, parent,
1926 root_objectid, owner, offset,
1927 refs_to_add, extent_op);
1928 ret = 0;
1929 }
1930 return ret;
1931 }
1932
1933 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1934 struct btrfs_root *root,
1935 struct btrfs_path *path,
1936 u64 bytenr, u64 parent, u64 root_objectid,
1937 u64 owner, u64 offset, int refs_to_add)
1938 {
1939 int ret;
1940 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1941 BUG_ON(refs_to_add != 1);
1942 ret = insert_tree_block_ref(trans, root, path, bytenr,
1943 parent, root_objectid);
1944 } else {
1945 ret = insert_extent_data_ref(trans, root, path, bytenr,
1946 parent, root_objectid,
1947 owner, offset, refs_to_add);
1948 }
1949 return ret;
1950 }
1951
1952 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1953 struct btrfs_root *root,
1954 struct btrfs_path *path,
1955 struct btrfs_extent_inline_ref *iref,
1956 int refs_to_drop, int is_data, int *last_ref)
1957 {
1958 int ret = 0;
1959
1960 BUG_ON(!is_data && refs_to_drop != 1);
1961 if (iref) {
1962 update_inline_extent_backref(root, path, iref,
1963 -refs_to_drop, NULL, last_ref);
1964 } else if (is_data) {
1965 ret = remove_extent_data_ref(trans, root, path, refs_to_drop,
1966 last_ref);
1967 } else {
1968 *last_ref = 1;
1969 ret = btrfs_del_item(trans, root, path);
1970 }
1971 return ret;
1972 }
1973
1974 #define in_range(b, first, len) ((b) >= (first) && (b) < (first) + (len))
1975 static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
1976 u64 *discarded_bytes)
1977 {
1978 int j, ret = 0;
1979 u64 bytes_left, end;
1980 u64 aligned_start = ALIGN(start, 1 << 9);
1981
1982 if (WARN_ON(start != aligned_start)) {
1983 len -= aligned_start - start;
1984 len = round_down(len, 1 << 9);
1985 start = aligned_start;
1986 }
1987
1988 *discarded_bytes = 0;
1989
1990 if (!len)
1991 return 0;
1992
1993 end = start + len;
1994 bytes_left = len;
1995
1996 /* Skip any superblocks on this device. */
1997 for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
1998 u64 sb_start = btrfs_sb_offset(j);
1999 u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
2000 u64 size = sb_start - start;
2001
2002 if (!in_range(sb_start, start, bytes_left) &&
2003 !in_range(sb_end, start, bytes_left) &&
2004 !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
2005 continue;
2006
2007 /*
2008 * Superblock spans beginning of range. Adjust start and
2009 * try again.
2010 */
2011 if (sb_start <= start) {
2012 start += sb_end - start;
2013 if (start > end) {
2014 bytes_left = 0;
2015 break;
2016 }
2017 bytes_left = end - start;
2018 continue;
2019 }
2020
2021 if (size) {
2022 ret = blkdev_issue_discard(bdev, start >> 9, size >> 9,
2023 GFP_NOFS, 0);
2024 if (!ret)
2025 *discarded_bytes += size;
2026 else if (ret != -EOPNOTSUPP)
2027 return ret;
2028 }
2029
2030 start = sb_end;
2031 if (start > end) {
2032 bytes_left = 0;
2033 break;
2034 }
2035 bytes_left = end - start;
2036 }
2037
2038 if (bytes_left) {
2039 ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9,
2040 GFP_NOFS, 0);
2041 if (!ret)
2042 *discarded_bytes += bytes_left;
2043 }
2044 return ret;
2045 }
2046
2047 int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
2048 u64 num_bytes, u64 *actual_bytes)
2049 {
2050 int ret;
2051 u64 discarded_bytes = 0;
2052 struct btrfs_bio *bbio = NULL;
2053
2054
2055 /*
2056 * Avoid races with device replace and make sure our bbio has devices
2057 * associated to its stripes that don't go away while we are discarding.
2058 */
2059 btrfs_bio_counter_inc_blocked(root->fs_info);
2060 /* Tell the block device(s) that the sectors can be discarded */
2061 ret = btrfs_map_block(root->fs_info, REQ_OP_DISCARD,
2062 bytenr, &num_bytes, &bbio, 0);
2063 /* Error condition is -ENOMEM */
2064 if (!ret) {
2065 struct btrfs_bio_stripe *stripe = bbio->stripes;
2066 int i;
2067
2068
2069 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
2070 u64 bytes;
2071 if (!stripe->dev->can_discard)
2072 continue;
2073
2074 ret = btrfs_issue_discard(stripe->dev->bdev,
2075 stripe->physical,
2076 stripe->length,
2077 &bytes);
2078 if (!ret)
2079 discarded_bytes += bytes;
2080 else if (ret != -EOPNOTSUPP)
2081 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
2082
2083 /*
2084 * Just in case we get back EOPNOTSUPP for some reason,
2085 * just ignore the return value so we don't screw up
2086 * people calling discard_extent.
2087 */
2088 ret = 0;
2089 }
2090 btrfs_put_bbio(bbio);
2091 }
2092 btrfs_bio_counter_dec(root->fs_info);
2093
2094 if (actual_bytes)
2095 *actual_bytes = discarded_bytes;
2096
2097
2098 if (ret == -EOPNOTSUPP)
2099 ret = 0;
2100 return ret;
2101 }
2102
2103 /* Can return -ENOMEM */
2104 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2105 struct btrfs_root *root,
2106 u64 bytenr, u64 num_bytes, u64 parent,
2107 u64 root_objectid, u64 owner, u64 offset)
2108 {
2109 int ret;
2110 struct btrfs_fs_info *fs_info = root->fs_info;
2111
2112 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
2113 root_objectid == BTRFS_TREE_LOG_OBJECTID);
2114
2115 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
2116 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
2117 num_bytes,
2118 parent, root_objectid, (int)owner,
2119 BTRFS_ADD_DELAYED_REF, NULL);
2120 } else {
2121 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
2122 num_bytes, parent, root_objectid,
2123 owner, offset, 0,
2124 BTRFS_ADD_DELAYED_REF, NULL);
2125 }
2126 return ret;
2127 }
2128
2129 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2130 struct btrfs_root *root,
2131 struct btrfs_delayed_ref_node *node,
2132 u64 parent, u64 root_objectid,
2133 u64 owner, u64 offset, int refs_to_add,
2134 struct btrfs_delayed_extent_op *extent_op)
2135 {
2136 struct btrfs_fs_info *fs_info = root->fs_info;
2137 struct btrfs_path *path;
2138 struct extent_buffer *leaf;
2139 struct btrfs_extent_item *item;
2140 struct btrfs_key key;
2141 u64 bytenr = node->bytenr;
2142 u64 num_bytes = node->num_bytes;
2143 u64 refs;
2144 int ret;
2145
2146 path = btrfs_alloc_path();
2147 if (!path)
2148 return -ENOMEM;
2149
2150 path->reada = READA_FORWARD;
2151 path->leave_spinning = 1;
2152 /* this will setup the path even if it fails to insert the back ref */
2153 ret = insert_inline_extent_backref(trans, fs_info->extent_root, path,
2154 bytenr, num_bytes, parent,
2155 root_objectid, owner, offset,
2156 refs_to_add, extent_op);
2157 if ((ret < 0 && ret != -EAGAIN) || !ret)
2158 goto out;
2159
2160 /*
2161 * Ok we had -EAGAIN which means we didn't have space to insert and
2162 * inline extent ref, so just update the reference count and add a
2163 * normal backref.
2164 */
2165 leaf = path->nodes[0];
2166 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2167 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2168 refs = btrfs_extent_refs(leaf, item);
2169 btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2170 if (extent_op)
2171 __run_delayed_extent_op(extent_op, leaf, item);
2172
2173 btrfs_mark_buffer_dirty(leaf);
2174 btrfs_release_path(path);
2175
2176 path->reada = READA_FORWARD;
2177 path->leave_spinning = 1;
2178 /* now insert the actual backref */
2179 ret = insert_extent_backref(trans, root->fs_info->extent_root,
2180 path, bytenr, parent, root_objectid,
2181 owner, offset, refs_to_add);
2182 if (ret)
2183 btrfs_abort_transaction(trans, ret);
2184 out:
2185 btrfs_free_path(path);
2186 return ret;
2187 }
2188
2189 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2190 struct btrfs_root *root,
2191 struct btrfs_delayed_ref_node *node,
2192 struct btrfs_delayed_extent_op *extent_op,
2193 int insert_reserved)
2194 {
2195 int ret = 0;
2196 struct btrfs_delayed_data_ref *ref;
2197 struct btrfs_key ins;
2198 u64 parent = 0;
2199 u64 ref_root = 0;
2200 u64 flags = 0;
2201
2202 ins.objectid = node->bytenr;
2203 ins.offset = node->num_bytes;
2204 ins.type = BTRFS_EXTENT_ITEM_KEY;
2205
2206 ref = btrfs_delayed_node_to_data_ref(node);
2207 trace_run_delayed_data_ref(root->fs_info, node, ref, node->action);
2208
2209 if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2210 parent = ref->parent;
2211 ref_root = ref->root;
2212
2213 if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2214 if (extent_op)
2215 flags |= extent_op->flags_to_set;
2216 ret = alloc_reserved_file_extent(trans, root,
2217 parent, ref_root, flags,
2218 ref->objectid, ref->offset,
2219 &ins, node->ref_mod);
2220 } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2221 ret = __btrfs_inc_extent_ref(trans, root, node, parent,
2222 ref_root, ref->objectid,
2223 ref->offset, node->ref_mod,
2224 extent_op);
2225 } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2226 ret = __btrfs_free_extent(trans, root, node, parent,
2227 ref_root, ref->objectid,
2228 ref->offset, node->ref_mod,
2229 extent_op);
2230 } else {
2231 BUG();
2232 }
2233 return ret;
2234 }
2235
2236 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2237 struct extent_buffer *leaf,
2238 struct btrfs_extent_item *ei)
2239 {
2240 u64 flags = btrfs_extent_flags(leaf, ei);
2241 if (extent_op->update_flags) {
2242 flags |= extent_op->flags_to_set;
2243 btrfs_set_extent_flags(leaf, ei, flags);
2244 }
2245
2246 if (extent_op->update_key) {
2247 struct btrfs_tree_block_info *bi;
2248 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2249 bi = (struct btrfs_tree_block_info *)(ei + 1);
2250 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2251 }
2252 }
2253
2254 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2255 struct btrfs_root *root,
2256 struct btrfs_delayed_ref_node *node,
2257 struct btrfs_delayed_extent_op *extent_op)
2258 {
2259 struct btrfs_key key;
2260 struct btrfs_path *path;
2261 struct btrfs_extent_item *ei;
2262 struct extent_buffer *leaf;
2263 u32 item_size;
2264 int ret;
2265 int err = 0;
2266 int metadata = !extent_op->is_data;
2267
2268 if (trans->aborted)
2269 return 0;
2270
2271 if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2272 metadata = 0;
2273
2274 path = btrfs_alloc_path();
2275 if (!path)
2276 return -ENOMEM;
2277
2278 key.objectid = node->bytenr;
2279
2280 if (metadata) {
2281 key.type = BTRFS_METADATA_ITEM_KEY;
2282 key.offset = extent_op->level;
2283 } else {
2284 key.type = BTRFS_EXTENT_ITEM_KEY;
2285 key.offset = node->num_bytes;
2286 }
2287
2288 again:
2289 path->reada = READA_FORWARD;
2290 path->leave_spinning = 1;
2291 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2292 path, 0, 1);
2293 if (ret < 0) {
2294 err = ret;
2295 goto out;
2296 }
2297 if (ret > 0) {
2298 if (metadata) {
2299 if (path->slots[0] > 0) {
2300 path->slots[0]--;
2301 btrfs_item_key_to_cpu(path->nodes[0], &key,
2302 path->slots[0]);
2303 if (key.objectid == node->bytenr &&
2304 key.type == BTRFS_EXTENT_ITEM_KEY &&
2305 key.offset == node->num_bytes)
2306 ret = 0;
2307 }
2308 if (ret > 0) {
2309 btrfs_release_path(path);
2310 metadata = 0;
2311
2312 key.objectid = node->bytenr;
2313 key.offset = node->num_bytes;
2314 key.type = BTRFS_EXTENT_ITEM_KEY;
2315 goto again;
2316 }
2317 } else {
2318 err = -EIO;
2319 goto out;
2320 }
2321 }
2322
2323 leaf = path->nodes[0];
2324 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2325 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2326 if (item_size < sizeof(*ei)) {
2327 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2328 path, (u64)-1, 0);
2329 if (ret < 0) {
2330 err = ret;
2331 goto out;
2332 }
2333 leaf = path->nodes[0];
2334 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2335 }
2336 #endif
2337 BUG_ON(item_size < sizeof(*ei));
2338 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2339 __run_delayed_extent_op(extent_op, leaf, ei);
2340
2341 btrfs_mark_buffer_dirty(leaf);
2342 out:
2343 btrfs_free_path(path);
2344 return err;
2345 }
2346
2347 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2348 struct btrfs_root *root,
2349 struct btrfs_delayed_ref_node *node,
2350 struct btrfs_delayed_extent_op *extent_op,
2351 int insert_reserved)
2352 {
2353 int ret = 0;
2354 struct btrfs_delayed_tree_ref *ref;
2355 struct btrfs_key ins;
2356 u64 parent = 0;
2357 u64 ref_root = 0;
2358 bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
2359 SKINNY_METADATA);
2360
2361 ref = btrfs_delayed_node_to_tree_ref(node);
2362 trace_run_delayed_tree_ref(root->fs_info, node, ref, node->action);
2363
2364 if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2365 parent = ref->parent;
2366 ref_root = ref->root;
2367
2368 ins.objectid = node->bytenr;
2369 if (skinny_metadata) {
2370 ins.offset = ref->level;
2371 ins.type = BTRFS_METADATA_ITEM_KEY;
2372 } else {
2373 ins.offset = node->num_bytes;
2374 ins.type = BTRFS_EXTENT_ITEM_KEY;
2375 }
2376
2377 BUG_ON(node->ref_mod != 1);
2378 if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2379 BUG_ON(!extent_op || !extent_op->update_flags);
2380 ret = alloc_reserved_tree_block(trans, root,
2381 parent, ref_root,
2382 extent_op->flags_to_set,
2383 &extent_op->key,
2384 ref->level, &ins);
2385 } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2386 ret = __btrfs_inc_extent_ref(trans, root, node,
2387 parent, ref_root,
2388 ref->level, 0, 1,
2389 extent_op);
2390 } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2391 ret = __btrfs_free_extent(trans, root, node,
2392 parent, ref_root,
2393 ref->level, 0, 1, extent_op);
2394 } else {
2395 BUG();
2396 }
2397 return ret;
2398 }
2399
2400 /* helper function to actually process a single delayed ref entry */
2401 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2402 struct btrfs_root *root,
2403 struct btrfs_delayed_ref_node *node,
2404 struct btrfs_delayed_extent_op *extent_op,
2405 int insert_reserved)
2406 {
2407 int ret = 0;
2408
2409 if (trans->aborted) {
2410 if (insert_reserved)
2411 btrfs_pin_extent(root, node->bytenr,
2412 node->num_bytes, 1);
2413 return 0;
2414 }
2415
2416 if (btrfs_delayed_ref_is_head(node)) {
2417 struct btrfs_delayed_ref_head *head;
2418 /*
2419 * we've hit the end of the chain and we were supposed
2420 * to insert this extent into the tree. But, it got
2421 * deleted before we ever needed to insert it, so all
2422 * we have to do is clean up the accounting
2423 */
2424 BUG_ON(extent_op);
2425 head = btrfs_delayed_node_to_head(node);
2426 trace_run_delayed_ref_head(root->fs_info, node, head,
2427 node->action);
2428
2429 if (insert_reserved) {
2430 btrfs_pin_extent(root, node->bytenr,
2431 node->num_bytes, 1);
2432 if (head->is_data) {
2433 ret = btrfs_del_csums(trans, root,
2434 node->bytenr,
2435 node->num_bytes);
2436 }
2437 }
2438
2439 /* Also free its reserved qgroup space */
2440 btrfs_qgroup_free_delayed_ref(root->fs_info,
2441 head->qgroup_ref_root,
2442 head->qgroup_reserved);
2443 return ret;
2444 }
2445
2446 if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2447 node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2448 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2449 insert_reserved);
2450 else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2451 node->type == BTRFS_SHARED_DATA_REF_KEY)
2452 ret = run_delayed_data_ref(trans, root, node, extent_op,
2453 insert_reserved);
2454 else
2455 BUG();
2456 return ret;
2457 }
2458
2459 static inline struct btrfs_delayed_ref_node *
2460 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2461 {
2462 struct btrfs_delayed_ref_node *ref;
2463
2464 if (list_empty(&head->ref_list))
2465 return NULL;
2466
2467 /*
2468 * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
2469 * This is to prevent a ref count from going down to zero, which deletes
2470 * the extent item from the extent tree, when there still are references
2471 * to add, which would fail because they would not find the extent item.
2472 */
2473 list_for_each_entry(ref, &head->ref_list, list) {
2474 if (ref->action == BTRFS_ADD_DELAYED_REF)
2475 return ref;
2476 }
2477
2478 return list_entry(head->ref_list.next, struct btrfs_delayed_ref_node,
2479 list);
2480 }
2481
2482 /*
2483 * Returns 0 on success or if called with an already aborted transaction.
2484 * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2485 */
2486 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2487 struct btrfs_root *root,
2488 unsigned long nr)
2489 {
2490 struct btrfs_delayed_ref_root *delayed_refs;
2491 struct btrfs_delayed_ref_node *ref;
2492 struct btrfs_delayed_ref_head *locked_ref = NULL;
2493 struct btrfs_delayed_extent_op *extent_op;
2494 struct btrfs_fs_info *fs_info = root->fs_info;
2495 ktime_t start = ktime_get();
2496 int ret;
2497 unsigned long count = 0;
2498 unsigned long actual_count = 0;
2499 int must_insert_reserved = 0;
2500
2501 delayed_refs = &trans->transaction->delayed_refs;
2502 while (1) {
2503 if (!locked_ref) {
2504 if (count >= nr)
2505 break;
2506
2507 spin_lock(&delayed_refs->lock);
2508 locked_ref = btrfs_select_ref_head(trans);
2509 if (!locked_ref) {
2510 spin_unlock(&delayed_refs->lock);
2511 break;
2512 }
2513
2514 /* grab the lock that says we are going to process
2515 * all the refs for this head */
2516 ret = btrfs_delayed_ref_lock(trans, locked_ref);
2517 spin_unlock(&delayed_refs->lock);
2518 /*
2519 * we may have dropped the spin lock to get the head
2520 * mutex lock, and that might have given someone else
2521 * time to free the head. If that's true, it has been
2522 * removed from our list and we can move on.
2523 */
2524 if (ret == -EAGAIN) {
2525 locked_ref = NULL;
2526 count++;
2527 continue;
2528 }
2529 }
2530
2531 /*
2532 * We need to try and merge add/drops of the same ref since we
2533 * can run into issues with relocate dropping the implicit ref
2534 * and then it being added back again before the drop can
2535 * finish. If we merged anything we need to re-loop so we can
2536 * get a good ref.
2537 * Or we can get node references of the same type that weren't
2538 * merged when created due to bumps in the tree mod seq, and
2539 * we need to merge them to prevent adding an inline extent
2540 * backref before dropping it (triggering a BUG_ON at
2541 * insert_inline_extent_backref()).
2542 */
2543 spin_lock(&locked_ref->lock);
2544 btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
2545 locked_ref);
2546
2547 /*
2548 * locked_ref is the head node, so we have to go one
2549 * node back for any delayed ref updates
2550 */
2551 ref = select_delayed_ref(locked_ref);
2552
2553 if (ref && ref->seq &&
2554 btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2555 spin_unlock(&locked_ref->lock);
2556 btrfs_delayed_ref_unlock(locked_ref);
2557 spin_lock(&delayed_refs->lock);
2558 locked_ref->processing = 0;
2559 delayed_refs->num_heads_ready++;
2560 spin_unlock(&delayed_refs->lock);
2561 locked_ref = NULL;
2562 cond_resched();
2563 count++;
2564 continue;
2565 }
2566
2567 /*
2568 * record the must insert reserved flag before we
2569 * drop the spin lock.
2570 */
2571 must_insert_reserved = locked_ref->must_insert_reserved;
2572 locked_ref->must_insert_reserved = 0;
2573
2574 extent_op = locked_ref->extent_op;
2575 locked_ref->extent_op = NULL;
2576
2577 if (!ref) {
2578
2579
2580 /* All delayed refs have been processed, Go ahead
2581 * and send the head node to run_one_delayed_ref,
2582 * so that any accounting fixes can happen
2583 */
2584 ref = &locked_ref->node;
2585
2586 if (extent_op && must_insert_reserved) {
2587 btrfs_free_delayed_extent_op(extent_op);
2588 extent_op = NULL;
2589 }
2590
2591 if (extent_op) {
2592 spin_unlock(&locked_ref->lock);
2593 ret = run_delayed_extent_op(trans, root,
2594 ref, extent_op);
2595 btrfs_free_delayed_extent_op(extent_op);
2596
2597 if (ret) {
2598 /*
2599 * Need to reset must_insert_reserved if
2600 * there was an error so the abort stuff
2601 * can cleanup the reserved space
2602 * properly.
2603 */
2604 if (must_insert_reserved)
2605 locked_ref->must_insert_reserved = 1;
2606 locked_ref->processing = 0;
2607 btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2608 btrfs_delayed_ref_unlock(locked_ref);
2609 return ret;
2610 }
2611 continue;
2612 }
2613
2614 /*
2615 * Need to drop our head ref lock and re-acquire the
2616 * delayed ref lock and then re-check to make sure
2617 * nobody got added.
2618 */
2619 spin_unlock(&locked_ref->lock);
2620 spin_lock(&delayed_refs->lock);
2621 spin_lock(&locked_ref->lock);
2622 if (!list_empty(&locked_ref->ref_list) ||
2623 locked_ref->extent_op) {
2624 spin_unlock(&locked_ref->lock);
2625 spin_unlock(&delayed_refs->lock);
2626 continue;
2627 }
2628 ref->in_tree = 0;
2629 delayed_refs->num_heads--;
2630 rb_erase(&locked_ref->href_node,
2631 &delayed_refs->href_root);
2632 spin_unlock(&delayed_refs->lock);
2633 } else {
2634 actual_count++;
2635 ref->in_tree = 0;
2636 list_del(&ref->list);
2637 }
2638 atomic_dec(&delayed_refs->num_entries);
2639
2640 if (!btrfs_delayed_ref_is_head(ref)) {
2641 /*
2642 * when we play the delayed ref, also correct the
2643 * ref_mod on head
2644 */
2645 switch (ref->action) {
2646 case BTRFS_ADD_DELAYED_REF:
2647 case BTRFS_ADD_DELAYED_EXTENT:
2648 locked_ref->node.ref_mod -= ref->ref_mod;
2649 break;
2650 case BTRFS_DROP_DELAYED_REF:
2651 locked_ref->node.ref_mod += ref->ref_mod;
2652 break;
2653 default:
2654 WARN_ON(1);
2655 }
2656 }
2657 spin_unlock(&locked_ref->lock);
2658
2659 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2660 must_insert_reserved);
2661
2662 btrfs_free_delayed_extent_op(extent_op);
2663 if (ret) {
2664 locked_ref->processing = 0;
2665 btrfs_delayed_ref_unlock(locked_ref);
2666 btrfs_put_delayed_ref(ref);
2667 btrfs_debug(fs_info, "run_one_delayed_ref returned %d", ret);
2668 return ret;
2669 }
2670
2671 /*
2672 * If this node is a head, that means all the refs in this head
2673 * have been dealt with, and we will pick the next head to deal
2674 * with, so we must unlock the head and drop it from the cluster
2675 * list before we release it.
2676 */
2677 if (btrfs_delayed_ref_is_head(ref)) {
2678 if (locked_ref->is_data &&
2679 locked_ref->total_ref_mod < 0) {
2680 spin_lock(&delayed_refs->lock);
2681 delayed_refs->pending_csums -= ref->num_bytes;
2682 spin_unlock(&delayed_refs->lock);
2683 }
2684 btrfs_delayed_ref_unlock(locked_ref);
2685 locked_ref = NULL;
2686 }
2687 btrfs_put_delayed_ref(ref);
2688 count++;
2689 cond_resched();
2690 }
2691
2692 /*
2693 * We don't want to include ref heads since we can have empty ref heads
2694 * and those will drastically skew our runtime down since we just do
2695 * accounting, no actual extent tree updates.
2696 */
2697 if (actual_count > 0) {
2698 u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2699 u64 avg;
2700
2701 /*
2702 * We weigh the current average higher than our current runtime
2703 * to avoid large swings in the average.
2704 */
2705 spin_lock(&delayed_refs->lock);
2706 avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2707 fs_info->avg_delayed_ref_runtime = avg >> 2; /* div by 4 */
2708 spin_unlock(&delayed_refs->lock);
2709 }
2710 return 0;
2711 }
2712
2713 #ifdef SCRAMBLE_DELAYED_REFS
2714 /*
2715 * Normally delayed refs get processed in ascending bytenr order. This
2716 * correlates in most cases to the order added. To expose dependencies on this
2717 * order, we start to process the tree in the middle instead of the beginning
2718 */
2719 static u64 find_middle(struct rb_root *root)
2720 {
2721 struct rb_node *n = root->rb_node;
2722 struct btrfs_delayed_ref_node *entry;
2723 int alt = 1;
2724 u64 middle;
2725 u64 first = 0, last = 0;
2726
2727 n = rb_first(root);
2728 if (n) {
2729 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2730 first = entry->bytenr;
2731 }
2732 n = rb_last(root);
2733 if (n) {
2734 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2735 last = entry->bytenr;
2736 }
2737 n = root->rb_node;
2738
2739 while (n) {
2740 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2741 WARN_ON(!entry->in_tree);
2742
2743 middle = entry->bytenr;
2744
2745 if (alt)
2746 n = n->rb_left;
2747 else
2748 n = n->rb_right;
2749
2750 alt = 1 - alt;
2751 }
2752 return middle;
2753 }
2754 #endif
2755
2756 static inline u64 heads_to_leaves(struct btrfs_root *root, u64 heads)
2757 {
2758 u64 num_bytes;
2759
2760 num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2761 sizeof(struct btrfs_extent_inline_ref));
2762 if (!btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2763 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2764
2765 /*
2766 * We don't ever fill up leaves all the way so multiply by 2 just to be
2767 * closer to what we're really going to want to use.
2768 */
2769 return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(root));
2770 }
2771
2772 /*
2773 * Takes the number of bytes to be csumm'ed and figures out how many leaves it
2774 * would require to store the csums for that many bytes.
2775 */
2776 u64 btrfs_csum_bytes_to_leaves(struct btrfs_root *root, u64 csum_bytes)
2777 {
2778 u64 csum_size;
2779 u64 num_csums_per_leaf;
2780 u64 num_csums;
2781
2782 csum_size = BTRFS_MAX_ITEM_SIZE(root);
2783 num_csums_per_leaf = div64_u64(csum_size,
2784 (u64)btrfs_super_csum_size(root->fs_info->super_copy));
2785 num_csums = div64_u64(csum_bytes, root->sectorsize);
2786 num_csums += num_csums_per_leaf - 1;
2787 num_csums = div64_u64(num_csums, num_csums_per_leaf);
2788 return num_csums;
2789 }
2790
2791 int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans,
2792 struct btrfs_root *root)
2793 {
2794 struct btrfs_block_rsv *global_rsv;
2795 u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2796 u64 csum_bytes = trans->transaction->delayed_refs.pending_csums;
2797 u64 num_dirty_bgs = trans->transaction->num_dirty_bgs;
2798 u64 num_bytes, num_dirty_bgs_bytes;
2799 int ret = 0;
2800
2801 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
2802 num_heads = heads_to_leaves(root, num_heads);
2803 if (num_heads > 1)
2804 num_bytes += (num_heads - 1) * root->nodesize;
2805 num_bytes <<= 1;
2806 num_bytes += btrfs_csum_bytes_to_leaves(root, csum_bytes) * root->nodesize;
2807 num_dirty_bgs_bytes = btrfs_calc_trans_metadata_size(root,
2808 num_dirty_bgs);
2809 global_rsv = &root->fs_info->global_block_rsv;
2810
2811 /*
2812 * If we can't allocate any more chunks lets make sure we have _lots_ of
2813 * wiggle room since running delayed refs can create more delayed refs.
2814 */
2815 if (global_rsv->space_info->full) {
2816 num_dirty_bgs_bytes <<= 1;
2817 num_bytes <<= 1;
2818 }
2819
2820 spin_lock(&global_rsv->lock);
2821 if (global_rsv->reserved <= num_bytes + num_dirty_bgs_bytes)
2822 ret = 1;
2823 spin_unlock(&global_rsv->lock);
2824 return ret;
2825 }
2826
2827 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2828 struct btrfs_root *root)
2829 {
2830 struct btrfs_fs_info *fs_info = root->fs_info;
2831 u64 num_entries =
2832 atomic_read(&trans->transaction->delayed_refs.num_entries);
2833 u64 avg_runtime;
2834 u64 val;
2835
2836 smp_mb();
2837 avg_runtime = fs_info->avg_delayed_ref_runtime;
2838 val = num_entries * avg_runtime;
2839 if (num_entries * avg_runtime >= NSEC_PER_SEC)
2840 return 1;
2841 if (val >= NSEC_PER_SEC / 2)
2842 return 2;
2843
2844 return btrfs_check_space_for_delayed_refs(trans, root);
2845 }
2846
2847 struct async_delayed_refs {
2848 struct btrfs_root *root;
2849 u64 transid;
2850 int count;
2851 int error;
2852 int sync;
2853 struct completion wait;
2854 struct btrfs_work work;
2855 };
2856
2857 static void delayed_ref_async_start(struct btrfs_work *work)
2858 {
2859 struct async_delayed_refs *async;
2860 struct btrfs_trans_handle *trans;
2861 int ret;
2862
2863 async = container_of(work, struct async_delayed_refs, work);
2864
2865 /* if the commit is already started, we don't need to wait here */
2866 if (btrfs_transaction_blocked(async->root->fs_info))
2867 goto done;
2868
2869 trans = btrfs_join_transaction(async->root);
2870 if (IS_ERR(trans)) {
2871 async->error = PTR_ERR(trans);
2872 goto done;
2873 }
2874
2875 /*
2876 * trans->sync means that when we call end_transaction, we won't
2877 * wait on delayed refs
2878 */
2879 trans->sync = true;
2880
2881 /* Don't bother flushing if we got into a different transaction */
2882 if (trans->transid > async->transid)
2883 goto end;
2884
2885 ret = btrfs_run_delayed_refs(trans, async->root, async->count);
2886 if (ret)
2887 async->error = ret;
2888 end:
2889 ret = btrfs_end_transaction(trans, async->root);
2890 if (ret && !async->error)
2891 async->error = ret;
2892 done:
2893 if (async->sync)
2894 complete(&async->wait);
2895 else
2896 kfree(async);
2897 }
2898
2899 int btrfs_async_run_delayed_refs(struct btrfs_root *root,
2900 unsigned long count, u64 transid, int wait)
2901 {
2902 struct async_delayed_refs *async;
2903 int ret;
2904
2905 async = kmalloc(sizeof(*async), GFP_NOFS);
2906 if (!async)
2907 return -ENOMEM;
2908
2909 async->root = root->fs_info->tree_root;
2910 async->count = count;
2911 async->error = 0;
2912 async->transid = transid;
2913 if (wait)
2914 async->sync = 1;
2915 else
2916 async->sync = 0;
2917 init_completion(&async->wait);
2918
2919 btrfs_init_work(&async->work, btrfs_extent_refs_helper,
2920 delayed_ref_async_start, NULL, NULL);
2921
2922 btrfs_queue_work(root->fs_info->extent_workers, &async->work);
2923
2924 if (wait) {
2925 wait_for_completion(&async->wait);
2926 ret = async->error;
2927 kfree(async);
2928 return ret;
2929 }
2930 return 0;
2931 }
2932
2933 /*
2934 * this starts processing the delayed reference count updates and
2935 * extent insertions we have queued up so far. count can be
2936 * 0, which means to process everything in the tree at the start
2937 * of the run (but not newly added entries), or it can be some target
2938 * number you'd like to process.
2939 *
2940 * Returns 0 on success or if called with an aborted transaction
2941 * Returns <0 on error and aborts the transaction
2942 */
2943 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2944 struct btrfs_root *root, unsigned long count)
2945 {
2946 struct rb_node *node;
2947 struct btrfs_delayed_ref_root *delayed_refs;
2948 struct btrfs_delayed_ref_head *head;
2949 int ret;
2950 int run_all = count == (unsigned long)-1;
2951 bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
2952
2953 /* We'll clean this up in btrfs_cleanup_transaction */
2954 if (trans->aborted)
2955 return 0;
2956
2957 if (root->fs_info->creating_free_space_tree)
2958 return 0;
2959
2960 if (root == root->fs_info->extent_root)
2961 root = root->fs_info->tree_root;
2962
2963 delayed_refs = &trans->transaction->delayed_refs;
2964 if (count == 0)
2965 count = atomic_read(&delayed_refs->num_entries) * 2;
2966
2967 again:
2968 #ifdef SCRAMBLE_DELAYED_REFS
2969 delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2970 #endif
2971 trans->can_flush_pending_bgs = false;
2972 ret = __btrfs_run_delayed_refs(trans, root, count);
2973 if (ret < 0) {
2974 btrfs_abort_transaction(trans, ret);
2975 return ret;
2976 }
2977
2978 if (run_all) {
2979 if (!list_empty(&trans->new_bgs))
2980 btrfs_create_pending_block_groups(trans, root);
2981
2982 spin_lock(&delayed_refs->lock);
2983 node = rb_first(&delayed_refs->href_root);
2984 if (!node) {
2985 spin_unlock(&delayed_refs->lock);
2986 goto out;
2987 }
2988 count = (unsigned long)-1;
2989
2990 while (node) {
2991 head = rb_entry(node, struct btrfs_delayed_ref_head,
2992 href_node);
2993 if (btrfs_delayed_ref_is_head(&head->node)) {
2994 struct btrfs_delayed_ref_node *ref;
2995
2996 ref = &head->node;
2997 atomic_inc(&ref->refs);
2998
2999 spin_unlock(&delayed_refs->lock);
3000 /*
3001 * Mutex was contended, block until it's
3002 * released and try again
3003 */
3004 mutex_lock(&head->mutex);
3005 mutex_unlock(&head->mutex);
3006
3007 btrfs_put_delayed_ref(ref);
3008 cond_resched();
3009 goto again;
3010 } else {
3011 WARN_ON(1);
3012 }
3013 node = rb_next(node);
3014 }
3015 spin_unlock(&delayed_refs->lock);
3016 cond_resched();
3017 goto again;
3018 }
3019 out:
3020 assert_qgroups_uptodate(trans);
3021 trans->can_flush_pending_bgs = can_flush_pending_bgs;
3022 return 0;
3023 }
3024
3025 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
3026 struct btrfs_root *root,
3027 u64 bytenr, u64 num_bytes, u64 flags,
3028 int level, int is_data)
3029 {
3030 struct btrfs_delayed_extent_op *extent_op;
3031 int ret;
3032
3033 extent_op = btrfs_alloc_delayed_extent_op();
3034 if (!extent_op)
3035 return -ENOMEM;
3036
3037 extent_op->flags_to_set = flags;
3038 extent_op->update_flags = true;
3039 extent_op->update_key = false;
3040 extent_op->is_data = is_data ? true : false;
3041 extent_op->level = level;
3042
3043 ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
3044 num_bytes, extent_op);
3045 if (ret)
3046 btrfs_free_delayed_extent_op(extent_op);
3047 return ret;
3048 }
3049
3050 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
3051 struct btrfs_root *root,
3052 struct btrfs_path *path,
3053 u64 objectid, u64 offset, u64 bytenr)
3054 {
3055 struct btrfs_delayed_ref_head *head;
3056 struct btrfs_delayed_ref_node *ref;
3057 struct btrfs_delayed_data_ref *data_ref;
3058 struct btrfs_delayed_ref_root *delayed_refs;
3059 int ret = 0;
3060
3061 delayed_refs = &trans->transaction->delayed_refs;
3062 spin_lock(&delayed_refs->lock);
3063 head = btrfs_find_delayed_ref_head(trans, bytenr);
3064 if (!head) {
3065 spin_unlock(&delayed_refs->lock);
3066 return 0;
3067 }
3068
3069 if (!mutex_trylock(&head->mutex)) {
3070 atomic_inc(&head->node.refs);
3071 spin_unlock(&delayed_refs->lock);
3072
3073 btrfs_release_path(path);
3074
3075 /*
3076 * Mutex was contended, block until it's released and let
3077 * caller try again
3078 */
3079 mutex_lock(&head->mutex);
3080 mutex_unlock(&head->mutex);
3081 btrfs_put_delayed_ref(&head->node);
3082 return -EAGAIN;
3083 }
3084 spin_unlock(&delayed_refs->lock);
3085
3086 spin_lock(&head->lock);
3087 list_for_each_entry(ref, &head->ref_list, list) {
3088 /* If it's a shared ref we know a cross reference exists */
3089 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
3090 ret = 1;
3091 break;
3092 }
3093
3094 data_ref = btrfs_delayed_node_to_data_ref(ref);
3095
3096 /*
3097 * If our ref doesn't match the one we're currently looking at
3098 * then we have a cross reference.
3099 */
3100 if (data_ref->root != root->root_key.objectid ||
3101 data_ref->objectid != objectid ||
3102 data_ref->offset != offset) {
3103 ret = 1;
3104 break;
3105 }
3106 }
3107 spin_unlock(&head->lock);
3108 mutex_unlock(&head->mutex);
3109 return ret;
3110 }
3111
3112 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
3113 struct btrfs_root *root,
3114 struct btrfs_path *path,
3115 u64 objectid, u64 offset, u64 bytenr)
3116 {
3117 struct btrfs_root *extent_root = root->fs_info->extent_root;
3118 struct extent_buffer *leaf;
3119 struct btrfs_extent_data_ref *ref;
3120 struct btrfs_extent_inline_ref *iref;
3121 struct btrfs_extent_item *ei;
3122 struct btrfs_key key;
3123 u32 item_size;
3124 int ret;
3125
3126 key.objectid = bytenr;
3127 key.offset = (u64)-1;
3128 key.type = BTRFS_EXTENT_ITEM_KEY;
3129
3130 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
3131 if (ret < 0)
3132 goto out;
3133 BUG_ON(ret == 0); /* Corruption */
3134
3135 ret = -ENOENT;
3136 if (path->slots[0] == 0)
3137 goto out;
3138
3139 path->slots[0]--;
3140 leaf = path->nodes[0];
3141 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3142
3143 if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
3144 goto out;
3145
3146 ret = 1;
3147 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
3148 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3149 if (item_size < sizeof(*ei)) {
3150 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3151 goto out;
3152 }
3153 #endif
3154 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
3155
3156 if (item_size != sizeof(*ei) +
3157 btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
3158 goto out;
3159
3160 if (btrfs_extent_generation(leaf, ei) <=
3161 btrfs_root_last_snapshot(&root->root_item))
3162 goto out;
3163
3164 iref = (struct btrfs_extent_inline_ref *)(ei + 1);
3165 if (btrfs_extent_inline_ref_type(leaf, iref) !=
3166 BTRFS_EXTENT_DATA_REF_KEY)
3167 goto out;
3168
3169 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
3170 if (btrfs_extent_refs(leaf, ei) !=
3171 btrfs_extent_data_ref_count(leaf, ref) ||
3172 btrfs_extent_data_ref_root(leaf, ref) !=
3173 root->root_key.objectid ||
3174 btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
3175 btrfs_extent_data_ref_offset(leaf, ref) != offset)
3176 goto out;
3177
3178 ret = 0;
3179 out:
3180 return ret;
3181 }
3182
3183 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
3184 struct btrfs_root *root,
3185 u64 objectid, u64 offset, u64 bytenr)
3186 {
3187 struct btrfs_path *path;
3188 int ret;
3189 int ret2;
3190
3191 path = btrfs_alloc_path();
3192 if (!path)
3193 return -ENOENT;
3194
3195 do {
3196 ret = check_committed_ref(trans, root, path, objectid,
3197 offset, bytenr);
3198 if (ret && ret != -ENOENT)
3199 goto out;
3200
3201 ret2 = check_delayed_ref(trans, root, path, objectid,
3202 offset, bytenr);
3203 } while (ret2 == -EAGAIN);
3204
3205 if (ret2 && ret2 != -ENOENT) {
3206 ret = ret2;
3207 goto out;
3208 }
3209
3210 if (ret != -ENOENT || ret2 != -ENOENT)
3211 ret = 0;
3212 out:
3213 btrfs_free_path(path);
3214 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3215 WARN_ON(ret > 0);
3216 return ret;
3217 }
3218
3219 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3220 struct btrfs_root *root,
3221 struct extent_buffer *buf,
3222 int full_backref, int inc)
3223 {
3224 u64 bytenr;
3225 u64 num_bytes;
3226 u64 parent;
3227 u64 ref_root;
3228 u32 nritems;
3229 struct btrfs_key key;
3230 struct btrfs_file_extent_item *fi;
3231 int i;
3232 int level;
3233 int ret = 0;
3234 int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
3235 u64, u64, u64, u64, u64, u64);
3236
3237
3238 if (btrfs_is_testing(root->fs_info))
3239 return 0;
3240
3241 ref_root = btrfs_header_owner(buf);
3242 nritems = btrfs_header_nritems(buf);
3243 level = btrfs_header_level(buf);
3244
3245 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
3246 return 0;
3247
3248 if (inc)
3249 process_func = btrfs_inc_extent_ref;
3250 else
3251 process_func = btrfs_free_extent;
3252
3253 if (full_backref)
3254 parent = buf->start;
3255 else
3256 parent = 0;
3257
3258 for (i = 0; i < nritems; i++) {
3259 if (level == 0) {
3260 btrfs_item_key_to_cpu(buf, &key, i);
3261 if (key.type != BTRFS_EXTENT_DATA_KEY)
3262 continue;
3263 fi = btrfs_item_ptr(buf, i,
3264 struct btrfs_file_extent_item);
3265 if (btrfs_file_extent_type(buf, fi) ==
3266 BTRFS_FILE_EXTENT_INLINE)
3267 continue;
3268 bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3269 if (bytenr == 0)
3270 continue;
3271
3272 num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3273 key.offset -= btrfs_file_extent_offset(buf, fi);
3274 ret = process_func(trans, root, bytenr, num_bytes,
3275 parent, ref_root, key.objectid,
3276 key.offset);
3277 if (ret)
3278 goto fail;
3279 } else {
3280 bytenr = btrfs_node_blockptr(buf, i);
3281 num_bytes = root->nodesize;
3282 ret = process_func(trans, root, bytenr, num_bytes,
3283 parent, ref_root, level - 1, 0);
3284 if (ret)
3285 goto fail;
3286 }
3287 }
3288 return 0;
3289 fail:
3290 return ret;
3291 }
3292
3293 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3294 struct extent_buffer *buf, int full_backref)
3295 {
3296 return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
3297 }
3298
3299 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3300 struct extent_buffer *buf, int full_backref)
3301 {
3302 return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
3303 }
3304
3305 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3306 struct btrfs_root *root,
3307 struct btrfs_path *path,
3308 struct btrfs_block_group_cache *cache)
3309 {
3310 int ret;
3311 struct btrfs_root *extent_root = root->fs_info->extent_root;
3312 unsigned long bi;
3313 struct extent_buffer *leaf;
3314
3315 ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3316 if (ret) {
3317 if (ret > 0)
3318 ret = -ENOENT;
3319 goto fail;
3320 }
3321
3322 leaf = path->nodes[0];
3323 bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3324 write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3325 btrfs_mark_buffer_dirty(leaf);
3326 fail:
3327 btrfs_release_path(path);
3328 return ret;
3329
3330 }
3331
3332 static struct btrfs_block_group_cache *
3333 next_block_group(struct btrfs_root *root,
3334 struct btrfs_block_group_cache *cache)
3335 {
3336 struct rb_node *node;
3337
3338 spin_lock(&root->fs_info->block_group_cache_lock);
3339
3340 /* If our block group was removed, we need a full search. */
3341 if (RB_EMPTY_NODE(&cache->cache_node)) {
3342 const u64 next_bytenr = cache->key.objectid + cache->key.offset;
3343
3344 spin_unlock(&root->fs_info->block_group_cache_lock);
3345 btrfs_put_block_group(cache);
3346 cache = btrfs_lookup_first_block_group(root->fs_info,
3347 next_bytenr);
3348 return cache;
3349 }
3350 node = rb_next(&cache->cache_node);
3351 btrfs_put_block_group(cache);
3352 if (node) {
3353 cache = rb_entry(node, struct btrfs_block_group_cache,
3354 cache_node);
3355 btrfs_get_block_group(cache);
3356 } else
3357 cache = NULL;
3358 spin_unlock(&root->fs_info->block_group_cache_lock);
3359 return cache;
3360 }
3361
3362 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3363 struct btrfs_trans_handle *trans,
3364 struct btrfs_path *path)
3365 {
3366 struct btrfs_root *root = block_group->fs_info->tree_root;
3367 struct inode *inode = NULL;
3368 u64 alloc_hint = 0;
3369 int dcs = BTRFS_DC_ERROR;
3370 u64 num_pages = 0;
3371 int retries = 0;
3372 int ret = 0;
3373
3374 /*
3375 * If this block group is smaller than 100 megs don't bother caching the
3376 * block group.
3377 */
3378 if (block_group->key.offset < (100 * SZ_1M)) {
3379 spin_lock(&block_group->lock);
3380 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3381 spin_unlock(&block_group->lock);
3382 return 0;
3383 }
3384
3385 if (trans->aborted)
3386 return 0;
3387 again:
3388 inode = lookup_free_space_inode(root, block_group, path);
3389 if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3390 ret = PTR_ERR(inode);
3391 btrfs_release_path(path);
3392 goto out;
3393 }
3394
3395 if (IS_ERR(inode)) {
3396 BUG_ON(retries);
3397 retries++;
3398
3399 if (block_group->ro)
3400 goto out_free;
3401
3402 ret = create_free_space_inode(root, trans, block_group, path);
3403 if (ret)
3404 goto out_free;
3405 goto again;
3406 }
3407
3408 /* We've already setup this transaction, go ahead and exit */
3409 if (block_group->cache_generation == trans->transid &&
3410 i_size_read(inode)) {
3411 dcs = BTRFS_DC_SETUP;
3412 goto out_put;
3413 }
3414
3415 /*
3416 * We want to set the generation to 0, that way if anything goes wrong
3417 * from here on out we know not to trust this cache when we load up next
3418 * time.
3419 */
3420 BTRFS_I(inode)->generation = 0;
3421 ret = btrfs_update_inode(trans, root, inode);
3422 if (ret) {
3423 /*
3424 * So theoretically we could recover from this, simply set the
3425 * super cache generation to 0 so we know to invalidate the
3426 * cache, but then we'd have to keep track of the block groups
3427 * that fail this way so we know we _have_ to reset this cache
3428 * before the next commit or risk reading stale cache. So to
3429 * limit our exposure to horrible edge cases lets just abort the
3430 * transaction, this only happens in really bad situations
3431 * anyway.
3432 */
3433 btrfs_abort_transaction(trans, ret);
3434 goto out_put;
3435 }
3436 WARN_ON(ret);
3437
3438 if (i_size_read(inode) > 0) {
3439 ret = btrfs_check_trunc_cache_free_space(root,
3440 &root->fs_info->global_block_rsv);
3441 if (ret)
3442 goto out_put;
3443
3444 ret = btrfs_truncate_free_space_cache(root, trans, NULL, inode);
3445 if (ret)
3446 goto out_put;
3447 }
3448
3449 spin_lock(&block_group->lock);
3450 if (block_group->cached != BTRFS_CACHE_FINISHED ||
3451 !btrfs_test_opt(root->fs_info, SPACE_CACHE)) {
3452 /*
3453 * don't bother trying to write stuff out _if_
3454 * a) we're not cached,
3455 * b) we're with nospace_cache mount option.
3456 */
3457 dcs = BTRFS_DC_WRITTEN;
3458 spin_unlock(&block_group->lock);
3459 goto out_put;
3460 }
3461 spin_unlock(&block_group->lock);
3462
3463 /*
3464 * We hit an ENOSPC when setting up the cache in this transaction, just
3465 * skip doing the setup, we've already cleared the cache so we're safe.
3466 */
3467 if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
3468 ret = -ENOSPC;
3469 goto out_put;
3470 }
3471
3472 /*
3473 * Try to preallocate enough space based on how big the block group is.
3474 * Keep in mind this has to include any pinned space which could end up
3475 * taking up quite a bit since it's not folded into the other space
3476 * cache.
3477 */
3478 num_pages = div_u64(block_group->key.offset, SZ_256M);
3479 if (!num_pages)
3480 num_pages = 1;
3481
3482 num_pages *= 16;
3483 num_pages *= PAGE_SIZE;
3484
3485 ret = btrfs_check_data_free_space(inode, 0, num_pages);
3486 if (ret)
3487 goto out_put;
3488
3489 ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3490 num_pages, num_pages,
3491 &alloc_hint);
3492 /*
3493 * Our cache requires contiguous chunks so that we don't modify a bunch
3494 * of metadata or split extents when writing the cache out, which means
3495 * we can enospc if we are heavily fragmented in addition to just normal
3496 * out of space conditions. So if we hit this just skip setting up any
3497 * other block groups for this transaction, maybe we'll unpin enough
3498 * space the next time around.
3499 */
3500 if (!ret)
3501 dcs = BTRFS_DC_SETUP;
3502 else if (ret == -ENOSPC)
3503 set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
3504 btrfs_free_reserved_data_space(inode, 0, num_pages);
3505
3506 out_put:
3507 iput(inode);
3508 out_free:
3509 btrfs_release_path(path);
3510 out:
3511 spin_lock(&block_group->lock);
3512 if (!ret && dcs == BTRFS_DC_SETUP)
3513 block_group->cache_generation = trans->transid;
3514 block_group->disk_cache_state = dcs;
3515 spin_unlock(&block_group->lock);
3516
3517 return ret;
3518 }
3519
3520 int btrfs_setup_space_cache(struct btrfs_trans_handle *trans,
3521 struct btrfs_root *root)
3522 {
3523 struct btrfs_block_group_cache *cache, *tmp;
3524 struct btrfs_transaction *cur_trans = trans->transaction;
3525 struct btrfs_path *path;
3526
3527 if (list_empty(&cur_trans->dirty_bgs) ||
3528 !btrfs_test_opt(root->fs_info, SPACE_CACHE))
3529 return 0;
3530
3531 path = btrfs_alloc_path();
3532 if (!path)
3533 return -ENOMEM;
3534
3535 /* Could add new block groups, use _safe just in case */
3536 list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
3537 dirty_list) {
3538 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3539 cache_save_setup(cache, trans, path);
3540 }
3541
3542 btrfs_free_path(path);
3543 return 0;
3544 }
3545
3546 /*
3547 * transaction commit does final block group cache writeback during a
3548 * critical section where nothing is allowed to change the FS. This is
3549 * required in order for the cache to actually match the block group,
3550 * but can introduce a lot of latency into the commit.
3551 *
3552 * So, btrfs_start_dirty_block_groups is here to kick off block group
3553 * cache IO. There's a chance we'll have to redo some of it if the
3554 * block group changes again during the commit, but it greatly reduces
3555 * the commit latency by getting rid of the easy block groups while
3556 * we're still allowing others to join the commit.
3557 */
3558 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans,
3559 struct btrfs_root *root)
3560 {
3561 struct btrfs_block_group_cache *cache;
3562 struct btrfs_transaction *cur_trans = trans->transaction;
3563 int ret = 0;
3564 int should_put;
3565 struct btrfs_path *path = NULL;
3566 LIST_HEAD(dirty);
3567 struct list_head *io = &cur_trans->io_bgs;
3568 int num_started = 0;
3569 int loops = 0;
3570
3571 spin_lock(&cur_trans->dirty_bgs_lock);
3572 if (list_empty(&cur_trans->dirty_bgs)) {
3573 spin_unlock(&cur_trans->dirty_bgs_lock);
3574 return 0;
3575 }
3576 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3577 spin_unlock(&cur_trans->dirty_bgs_lock);
3578
3579 again:
3580 /*
3581 * make sure all the block groups on our dirty list actually
3582 * exist
3583 */
3584 btrfs_create_pending_block_groups(trans, root);
3585
3586 if (!path) {
3587 path = btrfs_alloc_path();
3588 if (!path)
3589 return -ENOMEM;
3590 }
3591
3592 /*
3593 * cache_write_mutex is here only to save us from balance or automatic
3594 * removal of empty block groups deleting this block group while we are
3595 * writing out the cache
3596 */
3597 mutex_lock(&trans->transaction->cache_write_mutex);
3598 while (!list_empty(&dirty)) {
3599 cache = list_first_entry(&dirty,
3600 struct btrfs_block_group_cache,
3601 dirty_list);
3602 /*
3603 * this can happen if something re-dirties a block
3604 * group that is already under IO. Just wait for it to
3605 * finish and then do it all again
3606 */
3607 if (!list_empty(&cache->io_list)) {
3608 list_del_init(&cache->io_list);
3609 btrfs_wait_cache_io(root, trans, cache,
3610 &cache->io_ctl, path,
3611 cache->key.objectid);
3612 btrfs_put_block_group(cache);
3613 }
3614
3615
3616 /*
3617 * btrfs_wait_cache_io uses the cache->dirty_list to decide
3618 * if it should update the cache_state. Don't delete
3619 * until after we wait.
3620 *
3621 * Since we're not running in the commit critical section
3622 * we need the dirty_bgs_lock to protect from update_block_group
3623 */
3624 spin_lock(&cur_trans->dirty_bgs_lock);
3625 list_del_init(&cache->dirty_list);
3626 spin_unlock(&cur_trans->dirty_bgs_lock);
3627
3628 should_put = 1;
3629
3630 cache_save_setup(cache, trans, path);
3631
3632 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
3633 cache->io_ctl.inode = NULL;
3634 ret = btrfs_write_out_cache(root, trans, cache, path);
3635 if (ret == 0 && cache->io_ctl.inode) {
3636 num_started++;
3637 should_put = 0;
3638
3639 /*
3640 * the cache_write_mutex is protecting
3641 * the io_list
3642 */
3643 list_add_tail(&cache->io_list, io);
3644 } else {
3645 /*
3646 * if we failed to write the cache, the
3647 * generation will be bad and life goes on
3648 */
3649 ret = 0;
3650 }
3651 }
3652 if (!ret) {
3653 ret = write_one_cache_group(trans, root, path, cache);
3654 /*
3655 * Our block group might still be attached to the list
3656 * of new block groups in the transaction handle of some
3657 * other task (struct btrfs_trans_handle->new_bgs). This
3658 * means its block group item isn't yet in the extent
3659 * tree. If this happens ignore the error, as we will
3660 * try again later in the critical section of the
3661 * transaction commit.
3662 */
3663 if (ret == -ENOENT) {
3664 ret = 0;
3665 spin_lock(&cur_trans->dirty_bgs_lock);
3666 if (list_empty(&cache->dirty_list)) {
3667 list_add_tail(&cache->dirty_list,
3668 &cur_trans->dirty_bgs);
3669 btrfs_get_block_group(cache);
3670 }
3671 spin_unlock(&cur_trans->dirty_bgs_lock);
3672 } else if (ret) {
3673 btrfs_abort_transaction(trans, ret);
3674 }
3675 }
3676
3677 /* if its not on the io list, we need to put the block group */
3678 if (should_put)
3679 btrfs_put_block_group(cache);
3680
3681 if (ret)
3682 break;
3683
3684 /*
3685 * Avoid blocking other tasks for too long. It might even save
3686 * us from writing caches for block groups that are going to be
3687 * removed.
3688 */
3689 mutex_unlock(&trans->transaction->cache_write_mutex);
3690 mutex_lock(&trans->transaction->cache_write_mutex);
3691 }
3692 mutex_unlock(&trans->transaction->cache_write_mutex);
3693
3694 /*
3695 * go through delayed refs for all the stuff we've just kicked off
3696 * and then loop back (just once)
3697 */
3698 ret = btrfs_run_delayed_refs(trans, root, 0);
3699 if (!ret && loops == 0) {
3700 loops++;
3701 spin_lock(&cur_trans->dirty_bgs_lock);
3702 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3703 /*
3704 * dirty_bgs_lock protects us from concurrent block group
3705 * deletes too (not just cache_write_mutex).
3706 */
3707 if (!list_empty(&dirty)) {
3708 spin_unlock(&cur_trans->dirty_bgs_lock);
3709 goto again;
3710 }
3711 spin_unlock(&cur_trans->dirty_bgs_lock);
3712 }
3713
3714 btrfs_free_path(path);
3715 return ret;
3716 }
3717
3718 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3719 struct btrfs_root *root)
3720 {
3721 struct btrfs_block_group_cache *cache;
3722 struct btrfs_transaction *cur_trans = trans->transaction;
3723 int ret = 0;
3724 int should_put;
3725 struct btrfs_path *path;
3726 struct list_head *io = &cur_trans->io_bgs;
3727 int num_started = 0;
3728
3729 path = btrfs_alloc_path();
3730 if (!path)
3731 return -ENOMEM;
3732
3733 /*
3734 * Even though we are in the critical section of the transaction commit,
3735 * we can still have concurrent tasks adding elements to this
3736 * transaction's list of dirty block groups. These tasks correspond to
3737 * endio free space workers started when writeback finishes for a
3738 * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
3739 * allocate new block groups as a result of COWing nodes of the root
3740 * tree when updating the free space inode. The writeback for the space
3741 * caches is triggered by an earlier call to
3742 * btrfs_start_dirty_block_groups() and iterations of the following
3743 * loop.
3744 * Also we want to do the cache_save_setup first and then run the
3745 * delayed refs to make sure we have the best chance at doing this all
3746 * in one shot.
3747 */
3748 spin_lock(&cur_trans->dirty_bgs_lock);
3749 while (!list_empty(&cur_trans->dirty_bgs)) {
3750 cache = list_first_entry(&cur_trans->dirty_bgs,
3751 struct btrfs_block_group_cache,
3752 dirty_list);
3753
3754 /*
3755 * this can happen if cache_save_setup re-dirties a block
3756 * group that is already under IO. Just wait for it to
3757 * finish and then do it all again
3758 */
3759 if (!list_empty(&cache->io_list)) {
3760 spin_unlock(&cur_trans->dirty_bgs_lock);
3761 list_del_init(&cache->io_list);
3762 btrfs_wait_cache_io(root, trans, cache,
3763 &cache->io_ctl, path,
3764 cache->key.objectid);
3765 btrfs_put_block_group(cache);
3766 spin_lock(&cur_trans->dirty_bgs_lock);
3767 }
3768
3769 /*
3770 * don't remove from the dirty list until after we've waited
3771 * on any pending IO
3772 */
3773 list_del_init(&cache->dirty_list);
3774 spin_unlock(&cur_trans->dirty_bgs_lock);
3775 should_put = 1;
3776
3777 cache_save_setup(cache, trans, path);
3778
3779 if (!ret)
3780 ret = btrfs_run_delayed_refs(trans, root, (unsigned long) -1);
3781
3782 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
3783 cache->io_ctl.inode = NULL;
3784 ret = btrfs_write_out_cache(root, trans, cache, path);
3785 if (ret == 0 && cache->io_ctl.inode) {
3786 num_started++;
3787 should_put = 0;
3788 list_add_tail(&cache->io_list, io);
3789 } else {
3790 /*
3791 * if we failed to write the cache, the
3792 * generation will be bad and life goes on
3793 */
3794 ret = 0;
3795 }
3796 }
3797 if (!ret) {
3798 ret = write_one_cache_group(trans, root, path, cache);
3799 /*
3800 * One of the free space endio workers might have
3801 * created a new block group while updating a free space
3802 * cache's inode (at inode.c:btrfs_finish_ordered_io())
3803 * and hasn't released its transaction handle yet, in
3804 * which case the new block group is still attached to
3805 * its transaction handle and its creation has not
3806 * finished yet (no block group item in the extent tree
3807 * yet, etc). If this is the case, wait for all free
3808 * space endio workers to finish and retry. This is a
3809 * a very rare case so no need for a more efficient and
3810 * complex approach.
3811 */
3812 if (ret == -ENOENT) {
3813 wait_event(cur_trans->writer_wait,
3814 atomic_read(&cur_trans->num_writers) == 1);
3815 ret = write_one_cache_group(trans, root, path,
3816 cache);
3817 }
3818 if (ret)
3819 btrfs_abort_transaction(trans, ret);
3820 }
3821
3822 /* if its not on the io list, we need to put the block group */
3823 if (should_put)
3824 btrfs_put_block_group(cache);
3825 spin_lock(&cur_trans->dirty_bgs_lock);
3826 }
3827 spin_unlock(&cur_trans->dirty_bgs_lock);
3828
3829 while (!list_empty(io)) {
3830 cache = list_first_entry(io, struct btrfs_block_group_cache,
3831 io_list);
3832 list_del_init(&cache->io_list);
3833 btrfs_wait_cache_io(root, trans, cache,
3834 &cache->io_ctl, path, cache->key.objectid);
3835 btrfs_put_block_group(cache);
3836 }
3837
3838 btrfs_free_path(path);
3839 return ret;
3840 }
3841
3842 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3843 {
3844 struct btrfs_block_group_cache *block_group;
3845 int readonly = 0;
3846
3847 block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3848 if (!block_group || block_group->ro)
3849 readonly = 1;
3850 if (block_group)
3851 btrfs_put_block_group(block_group);
3852 return readonly;
3853 }
3854
3855 bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3856 {
3857 struct btrfs_block_group_cache *bg;
3858 bool ret = true;
3859
3860 bg = btrfs_lookup_block_group(fs_info, bytenr);
3861 if (!bg)
3862 return false;
3863
3864 spin_lock(&bg->lock);
3865 if (bg->ro)
3866 ret = false;
3867 else
3868 atomic_inc(&bg->nocow_writers);
3869 spin_unlock(&bg->lock);
3870
3871 /* no put on block group, done by btrfs_dec_nocow_writers */
3872 if (!ret)
3873 btrfs_put_block_group(bg);
3874
3875 return ret;
3876
3877 }
3878
3879 void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3880 {
3881 struct btrfs_block_group_cache *bg;
3882
3883 bg = btrfs_lookup_block_group(fs_info, bytenr);
3884 ASSERT(bg);
3885 if (atomic_dec_and_test(&bg->nocow_writers))
3886 wake_up_atomic_t(&bg->nocow_writers);
3887 /*
3888 * Once for our lookup and once for the lookup done by a previous call
3889 * to btrfs_inc_nocow_writers()
3890 */
3891 btrfs_put_block_group(bg);
3892 btrfs_put_block_group(bg);
3893 }
3894
3895 static int btrfs_wait_nocow_writers_atomic_t(atomic_t *a)
3896 {
3897 schedule();
3898 return 0;
3899 }
3900
3901 void btrfs_wait_nocow_writers(struct btrfs_block_group_cache *bg)
3902 {
3903 wait_on_atomic_t(&bg->nocow_writers,
3904 btrfs_wait_nocow_writers_atomic_t,
3905 TASK_UNINTERRUPTIBLE);
3906 }
3907
3908 static const char *alloc_name(u64 flags)
3909 {
3910 switch (flags) {
3911 case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
3912 return "mixed";
3913 case BTRFS_BLOCK_GROUP_METADATA:
3914 return "metadata";
3915 case BTRFS_BLOCK_GROUP_DATA:
3916 return "data";
3917 case BTRFS_BLOCK_GROUP_SYSTEM:
3918 return "system";
3919 default:
3920 WARN_ON(1);
3921 return "invalid-combination";
3922 };
3923 }
3924
3925 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3926 u64 total_bytes, u64 bytes_used,
3927 u64 bytes_readonly,
3928 struct btrfs_space_info **space_info)
3929 {
3930 struct btrfs_space_info *found;
3931 int i;
3932 int factor;
3933 int ret;
3934
3935 if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3936 BTRFS_BLOCK_GROUP_RAID10))
3937 factor = 2;
3938 else
3939 factor = 1;
3940
3941 found = __find_space_info(info, flags);
3942 if (found) {
3943 spin_lock(&found->lock);
3944 found->total_bytes += total_bytes;
3945 found->disk_total += total_bytes * factor;
3946 found->bytes_used += bytes_used;
3947 found->disk_used += bytes_used * factor;
3948 found->bytes_readonly += bytes_readonly;
3949 if (total_bytes > 0)
3950 found->full = 0;
3951 space_info_add_new_bytes(info, found, total_bytes -
3952 bytes_used - bytes_readonly);
3953 spin_unlock(&found->lock);
3954 *space_info = found;
3955 return 0;
3956 }
3957 found = kzalloc(sizeof(*found), GFP_NOFS);
3958 if (!found)
3959 return -ENOMEM;
3960
3961 ret = percpu_counter_init(&found->total_bytes_pinned, 0, GFP_KERNEL);
3962 if (ret) {
3963 kfree(found);
3964 return ret;
3965 }
3966
3967 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3968 INIT_LIST_HEAD(&found->block_groups[i]);
3969 init_rwsem(&found->groups_sem);
3970 spin_lock_init(&found->lock);
3971 found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3972 found->total_bytes = total_bytes;
3973 found->disk_total = total_bytes * factor;
3974 found->bytes_used = bytes_used;
3975 found->disk_used = bytes_used * factor;
3976 found->bytes_pinned = 0;
3977 found->bytes_reserved = 0;
3978 found->bytes_readonly = bytes_readonly;
3979 found->bytes_may_use = 0;
3980 found->full = 0;
3981 found->max_extent_size = 0;
3982 found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3983 found->chunk_alloc = 0;
3984 found->flush = 0;
3985 init_waitqueue_head(&found->wait);
3986 INIT_LIST_HEAD(&found->ro_bgs);
3987 INIT_LIST_HEAD(&found->tickets);
3988 INIT_LIST_HEAD(&found->priority_tickets);
3989
3990 ret = kobject_init_and_add(&found->kobj, &space_info_ktype,
3991 info->space_info_kobj, "%s",
3992 alloc_name(found->flags));
3993 if (ret) {
3994 kfree(found);
3995 return ret;
3996 }
3997
3998 *space_info = found;
3999 list_add_rcu(&found->list, &info->space_info);
4000 if (flags & BTRFS_BLOCK_GROUP_DATA)
4001 info->data_sinfo = found;
4002
4003 return ret;
4004 }
4005
4006 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
4007 {
4008 u64 extra_flags = chunk_to_extended(flags) &
4009 BTRFS_EXTENDED_PROFILE_MASK;
4010
4011 write_seqlock(&fs_info->profiles_lock);
4012 if (flags & BTRFS_BLOCK_GROUP_DATA)
4013 fs_info->avail_data_alloc_bits |= extra_flags;
4014 if (flags & BTRFS_BLOCK_GROUP_METADATA)
4015 fs_info->avail_metadata_alloc_bits |= extra_flags;
4016 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4017 fs_info->avail_system_alloc_bits |= extra_flags;
4018 write_sequnlock(&fs_info->profiles_lock);
4019 }
4020
4021 /*
4022 * returns target flags in extended format or 0 if restripe for this
4023 * chunk_type is not in progress
4024 *
4025 * should be called with either volume_mutex or balance_lock held
4026 */
4027 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
4028 {
4029 struct btrfs_balance_control *bctl = fs_info->balance_ctl;
4030 u64 target = 0;
4031
4032 if (!bctl)
4033 return 0;
4034
4035 if (flags & BTRFS_BLOCK_GROUP_DATA &&
4036 bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4037 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
4038 } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
4039 bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4040 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
4041 } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
4042 bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4043 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
4044 }
4045
4046 return target;
4047 }
4048
4049 /*
4050 * @flags: available profiles in extended format (see ctree.h)
4051 *
4052 * Returns reduced profile in chunk format. If profile changing is in
4053 * progress (either running or paused) picks the target profile (if it's
4054 * already available), otherwise falls back to plain reducing.
4055 */
4056 static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
4057 {
4058 u64 num_devices = root->fs_info->fs_devices->rw_devices;
4059 u64 target;
4060 u64 raid_type;
4061 u64 allowed = 0;
4062
4063 /*
4064 * see if restripe for this chunk_type is in progress, if so
4065 * try to reduce to the target profile
4066 */
4067 spin_lock(&root->fs_info->balance_lock);
4068 target = get_restripe_target(root->fs_info, flags);
4069 if (target) {
4070 /* pick target profile only if it's already available */
4071 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
4072 spin_unlock(&root->fs_info->balance_lock);
4073 return extended_to_chunk(target);
4074 }
4075 }
4076 spin_unlock(&root->fs_info->balance_lock);
4077
4078 /* First, mask out the RAID levels which aren't possible */
4079 for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
4080 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
4081 allowed |= btrfs_raid_group[raid_type];
4082 }
4083 allowed &= flags;
4084
4085 if (allowed & BTRFS_BLOCK_GROUP_RAID6)
4086 allowed = BTRFS_BLOCK_GROUP_RAID6;
4087 else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
4088 allowed = BTRFS_BLOCK_GROUP_RAID5;
4089 else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
4090 allowed = BTRFS_BLOCK_GROUP_RAID10;
4091 else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
4092 allowed = BTRFS_BLOCK_GROUP_RAID1;
4093 else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
4094 allowed = BTRFS_BLOCK_GROUP_RAID0;
4095
4096 flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
4097
4098 return extended_to_chunk(flags | allowed);
4099 }
4100
4101 static u64 get_alloc_profile(struct btrfs_root *root, u64 orig_flags)
4102 {
4103 unsigned seq;
4104 u64 flags;
4105
4106 do {
4107 flags = orig_flags;
4108 seq = read_seqbegin(&root->fs_info->profiles_lock);
4109
4110 if (flags & BTRFS_BLOCK_GROUP_DATA)
4111 flags |= root->fs_info->avail_data_alloc_bits;
4112 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4113 flags |= root->fs_info->avail_system_alloc_bits;
4114 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
4115 flags |= root->fs_info->avail_metadata_alloc_bits;
4116 } while (read_seqretry(&root->fs_info->profiles_lock, seq));
4117
4118 return btrfs_reduce_alloc_profile(root, flags);
4119 }
4120
4121 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
4122 {
4123 u64 flags;
4124 u64 ret;
4125
4126 if (data)
4127 flags = BTRFS_BLOCK_GROUP_DATA;
4128 else if (root == root->fs_info->chunk_root)
4129 flags = BTRFS_BLOCK_GROUP_SYSTEM;
4130 else
4131 flags = BTRFS_BLOCK_GROUP_METADATA;
4132
4133 ret = get_alloc_profile(root, flags);
4134 return ret;
4135 }
4136
4137 int btrfs_alloc_data_chunk_ondemand(struct inode *inode, u64 bytes)
4138 {
4139 struct btrfs_space_info *data_sinfo;
4140 struct btrfs_root *root = BTRFS_I(inode)->root;
4141 struct btrfs_fs_info *fs_info = root->fs_info;
4142 u64 used;
4143 int ret = 0;
4144 int need_commit = 2;
4145 int have_pinned_space;
4146
4147 /* make sure bytes are sectorsize aligned */
4148 bytes = ALIGN(bytes, root->sectorsize);
4149
4150 if (btrfs_is_free_space_inode(inode)) {
4151 need_commit = 0;
4152 ASSERT(current->journal_info);
4153 }
4154
4155 data_sinfo = fs_info->data_sinfo;
4156 if (!data_sinfo)
4157 goto alloc;
4158
4159 again:
4160 /* make sure we have enough space to handle the data first */
4161 spin_lock(&data_sinfo->lock);
4162 used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
4163 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
4164 data_sinfo->bytes_may_use;
4165
4166 if (used + bytes > data_sinfo->total_bytes) {
4167 struct btrfs_trans_handle *trans;
4168
4169 /*
4170 * if we don't have enough free bytes in this space then we need
4171 * to alloc a new chunk.
4172 */
4173 if (!data_sinfo->full) {
4174 u64 alloc_target;
4175
4176 data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
4177 spin_unlock(&data_sinfo->lock);
4178 alloc:
4179 alloc_target = btrfs_get_alloc_profile(root, 1);
4180 /*
4181 * It is ugly that we don't call nolock join
4182 * transaction for the free space inode case here.
4183 * But it is safe because we only do the data space
4184 * reservation for the free space cache in the
4185 * transaction context, the common join transaction
4186 * just increase the counter of the current transaction
4187 * handler, doesn't try to acquire the trans_lock of
4188 * the fs.
4189 */
4190 trans = btrfs_join_transaction(root);
4191 if (IS_ERR(trans))
4192 return PTR_ERR(trans);
4193
4194 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4195 alloc_target,
4196 CHUNK_ALLOC_NO_FORCE);
4197 btrfs_end_transaction(trans, root);
4198 if (ret < 0) {
4199 if (ret != -ENOSPC)
4200 return ret;
4201 else {
4202 have_pinned_space = 1;
4203 goto commit_trans;
4204 }
4205 }
4206
4207 if (!data_sinfo)
4208 data_sinfo = fs_info->data_sinfo;
4209
4210 goto again;
4211 }
4212
4213 /*
4214 * If we don't have enough pinned space to deal with this
4215 * allocation, and no removed chunk in current transaction,
4216 * don't bother committing the transaction.
4217 */
4218 have_pinned_space = percpu_counter_compare(
4219 &data_sinfo->total_bytes_pinned,
4220 used + bytes - data_sinfo->total_bytes);
4221 spin_unlock(&data_sinfo->lock);
4222
4223 /* commit the current transaction and try again */
4224 commit_trans:
4225 if (need_commit &&
4226 !atomic_read(&root->fs_info->open_ioctl_trans)) {
4227 need_commit--;
4228
4229 if (need_commit > 0) {
4230 btrfs_start_delalloc_roots(fs_info, 0, -1);
4231 btrfs_wait_ordered_roots(fs_info, -1, 0, (u64)-1);
4232 }
4233
4234 trans = btrfs_join_transaction(root);
4235 if (IS_ERR(trans))
4236 return PTR_ERR(trans);
4237 if (have_pinned_space >= 0 ||
4238 test_bit(BTRFS_TRANS_HAVE_FREE_BGS,
4239 &trans->transaction->flags) ||
4240 need_commit > 0) {
4241 ret = btrfs_commit_transaction(trans, root);
4242 if (ret)
4243 return ret;
4244 /*
4245 * The cleaner kthread might still be doing iput
4246 * operations. Wait for it to finish so that
4247 * more space is released.
4248 */
4249 mutex_lock(&root->fs_info->cleaner_delayed_iput_mutex);
4250 mutex_unlock(&root->fs_info->cleaner_delayed_iput_mutex);
4251 goto again;
4252 } else {
4253 btrfs_end_transaction(trans, root);
4254 }
4255 }
4256
4257 trace_btrfs_space_reservation(root->fs_info,
4258 "space_info:enospc",
4259 data_sinfo->flags, bytes, 1);
4260 return -ENOSPC;
4261 }
4262 data_sinfo->bytes_may_use += bytes;
4263 trace_btrfs_space_reservation(root->fs_info, "space_info",
4264 data_sinfo->flags, bytes, 1);
4265 spin_unlock(&data_sinfo->lock);
4266
4267 return ret;
4268 }
4269
4270 /*
4271 * New check_data_free_space() with ability for precious data reservation
4272 * Will replace old btrfs_check_data_free_space(), but for patch split,
4273 * add a new function first and then replace it.
4274 */
4275 int btrfs_check_data_free_space(struct inode *inode, u64 start, u64 len)
4276 {
4277 struct btrfs_root *root = BTRFS_I(inode)->root;
4278 int ret;
4279
4280 /* align the range */
4281 len = round_up(start + len, root->sectorsize) -
4282 round_down(start, root->sectorsize);
4283 start = round_down(start, root->sectorsize);
4284
4285 ret = btrfs_alloc_data_chunk_ondemand(inode, len);
4286 if (ret < 0)
4287 return ret;
4288
4289 /*
4290 * Use new btrfs_qgroup_reserve_data to reserve precious data space
4291 *
4292 * TODO: Find a good method to avoid reserve data space for NOCOW
4293 * range, but don't impact performance on quota disable case.
4294 */
4295 ret = btrfs_qgroup_reserve_data(inode, start, len);
4296 return ret;
4297 }
4298
4299 /*
4300 * Called if we need to clear a data reservation for this inode
4301 * Normally in a error case.
4302 *
4303 * This one will *NOT* use accurate qgroup reserved space API, just for case
4304 * which we can't sleep and is sure it won't affect qgroup reserved space.
4305 * Like clear_bit_hook().
4306 */
4307 void btrfs_free_reserved_data_space_noquota(struct inode *inode, u64 start,
4308 u64 len)
4309 {
4310 struct btrfs_root *root = BTRFS_I(inode)->root;
4311 struct btrfs_space_info *data_sinfo;
4312
4313 /* Make sure the range is aligned to sectorsize */
4314 len = round_up(start + len, root->sectorsize) -
4315 round_down(start, root->sectorsize);
4316 start = round_down(start, root->sectorsize);
4317
4318 data_sinfo = root->fs_info->data_sinfo;
4319 spin_lock(&data_sinfo->lock);
4320 if (WARN_ON(data_sinfo->bytes_may_use < len))
4321 data_sinfo->bytes_may_use = 0;
4322 else
4323 data_sinfo->bytes_may_use -= len;
4324 trace_btrfs_space_reservation(root->fs_info, "space_info",
4325 data_sinfo->flags, len, 0);
4326 spin_unlock(&data_sinfo->lock);
4327 }
4328
4329 /*
4330 * Called if we need to clear a data reservation for this inode
4331 * Normally in a error case.
4332 *
4333 * This one will handle the per-inode data rsv map for accurate reserved
4334 * space framework.
4335 */
4336 void btrfs_free_reserved_data_space(struct inode *inode, u64 start, u64 len)
4337 {
4338 btrfs_free_reserved_data_space_noquota(inode, start, len);
4339 btrfs_qgroup_free_data(inode, start, len);
4340 }
4341
4342 static void force_metadata_allocation(struct btrfs_fs_info *info)
4343 {
4344 struct list_head *head = &info->space_info;
4345 struct btrfs_space_info *found;
4346
4347 rcu_read_lock();
4348 list_for_each_entry_rcu(found, head, list) {
4349 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
4350 found->force_alloc = CHUNK_ALLOC_FORCE;
4351 }
4352 rcu_read_unlock();
4353 }
4354
4355 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
4356 {
4357 return (global->size << 1);
4358 }
4359
4360 static int should_alloc_chunk(struct btrfs_root *root,
4361 struct btrfs_space_info *sinfo, int force)
4362 {
4363 struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4364 u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
4365 u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
4366 u64 thresh;
4367
4368 if (force == CHUNK_ALLOC_FORCE)
4369 return 1;
4370
4371 /*
4372 * We need to take into account the global rsv because for all intents
4373 * and purposes it's used space. Don't worry about locking the
4374 * global_rsv, it doesn't change except when the transaction commits.
4375 */
4376 if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
4377 num_allocated += calc_global_rsv_need_space(global_rsv);
4378
4379 /*
4380 * in limited mode, we want to have some free space up to
4381 * about 1% of the FS size.
4382 */
4383 if (force == CHUNK_ALLOC_LIMITED) {
4384 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
4385 thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
4386
4387 if (num_bytes - num_allocated < thresh)
4388 return 1;
4389 }
4390
4391 if (num_allocated + SZ_2M < div_factor(num_bytes, 8))
4392 return 0;
4393 return 1;
4394 }
4395
4396 static u64 get_profile_num_devs(struct btrfs_root *root, u64 type)
4397 {
4398 u64 num_dev;
4399
4400 if (type & (BTRFS_BLOCK_GROUP_RAID10 |
4401 BTRFS_BLOCK_GROUP_RAID0 |
4402 BTRFS_BLOCK_GROUP_RAID5 |
4403 BTRFS_BLOCK_GROUP_RAID6))
4404 num_dev = root->fs_info->fs_devices->rw_devices;
4405 else if (type & BTRFS_BLOCK_GROUP_RAID1)
4406 num_dev = 2;
4407 else
4408 num_dev = 1; /* DUP or single */
4409
4410 return num_dev;
4411 }
4412
4413 /*
4414 * If @is_allocation is true, reserve space in the system space info necessary
4415 * for allocating a chunk, otherwise if it's false, reserve space necessary for
4416 * removing a chunk.
4417 */
4418 void check_system_chunk(struct btrfs_trans_handle *trans,
4419 struct btrfs_root *root,
4420 u64 type)
4421 {
4422 struct btrfs_space_info *info;
4423 u64 left;
4424 u64 thresh;
4425 int ret = 0;
4426 u64 num_devs;
4427
4428 /*
4429 * Needed because we can end up allocating a system chunk and for an
4430 * atomic and race free space reservation in the chunk block reserve.
4431 */
4432 ASSERT(mutex_is_locked(&root->fs_info->chunk_mutex));
4433
4434 info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4435 spin_lock(&info->lock);
4436 left = info->total_bytes - info->bytes_used - info->bytes_pinned -
4437 info->bytes_reserved - info->bytes_readonly -
4438 info->bytes_may_use;
4439 spin_unlock(&info->lock);
4440
4441 num_devs = get_profile_num_devs(root, type);
4442
4443 /* num_devs device items to update and 1 chunk item to add or remove */
4444 thresh = btrfs_calc_trunc_metadata_size(root, num_devs) +
4445 btrfs_calc_trans_metadata_size(root, 1);
4446
4447 if (left < thresh && btrfs_test_opt(root->fs_info, ENOSPC_DEBUG)) {
4448 btrfs_info(root->fs_info, "left=%llu, need=%llu, flags=%llu",
4449 left, thresh, type);
4450 dump_space_info(info, 0, 0);
4451 }
4452
4453 if (left < thresh) {
4454 u64 flags;
4455
4456 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
4457 /*
4458 * Ignore failure to create system chunk. We might end up not
4459 * needing it, as we might not need to COW all nodes/leafs from
4460 * the paths we visit in the chunk tree (they were already COWed
4461 * or created in the current transaction for example).
4462 */
4463 ret = btrfs_alloc_chunk(trans, root, flags);
4464 }
4465
4466 if (!ret) {
4467 ret = btrfs_block_rsv_add(root->fs_info->chunk_root,
4468 &root->fs_info->chunk_block_rsv,
4469 thresh, BTRFS_RESERVE_NO_FLUSH);
4470 if (!ret)
4471 trans->chunk_bytes_reserved += thresh;
4472 }
4473 }
4474
4475 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
4476 struct btrfs_root *extent_root, u64 flags, int force)
4477 {
4478 struct btrfs_space_info *space_info;
4479 struct btrfs_fs_info *fs_info = extent_root->fs_info;
4480 int wait_for_alloc = 0;
4481 int ret = 0;
4482
4483 /* Don't re-enter if we're already allocating a chunk */
4484 if (trans->allocating_chunk)
4485 return -ENOSPC;
4486
4487 space_info = __find_space_info(extent_root->fs_info, flags);
4488 if (!space_info) {
4489 ret = update_space_info(extent_root->fs_info, flags,
4490 0, 0, 0, &space_info);
4491 BUG_ON(ret); /* -ENOMEM */
4492 }
4493 BUG_ON(!space_info); /* Logic error */
4494
4495 again:
4496 spin_lock(&space_info->lock);
4497 if (force < space_info->force_alloc)
4498 force = space_info->force_alloc;
4499 if (space_info->full) {
4500 if (should_alloc_chunk(extent_root, space_info, force))
4501 ret = -ENOSPC;
4502 else
4503 ret = 0;
4504 spin_unlock(&space_info->lock);
4505 return ret;
4506 }
4507
4508 if (!should_alloc_chunk(extent_root, space_info, force)) {
4509 spin_unlock(&space_info->lock);
4510 return 0;
4511 } else if (space_info->chunk_alloc) {
4512 wait_for_alloc = 1;
4513 } else {
4514 space_info->chunk_alloc = 1;
4515 }
4516
4517 spin_unlock(&space_info->lock);
4518
4519 mutex_lock(&fs_info->chunk_mutex);
4520
4521 /*
4522 * The chunk_mutex is held throughout the entirety of a chunk
4523 * allocation, so once we've acquired the chunk_mutex we know that the
4524 * other guy is done and we need to recheck and see if we should
4525 * allocate.
4526 */
4527 if (wait_for_alloc) {
4528 mutex_unlock(&fs_info->chunk_mutex);
4529 wait_for_alloc = 0;
4530 goto again;
4531 }
4532
4533 trans->allocating_chunk = true;
4534
4535 /*
4536 * If we have mixed data/metadata chunks we want to make sure we keep
4537 * allocating mixed chunks instead of individual chunks.
4538 */
4539 if (btrfs_mixed_space_info(space_info))
4540 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
4541
4542 /*
4543 * if we're doing a data chunk, go ahead and make sure that
4544 * we keep a reasonable number of metadata chunks allocated in the
4545 * FS as well.
4546 */
4547 if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
4548 fs_info->data_chunk_allocations++;
4549 if (!(fs_info->data_chunk_allocations %
4550 fs_info->metadata_ratio))
4551 force_metadata_allocation(fs_info);
4552 }
4553
4554 /*
4555 * Check if we have enough space in SYSTEM chunk because we may need
4556 * to update devices.
4557 */
4558 check_system_chunk(trans, extent_root, flags);
4559
4560 ret = btrfs_alloc_chunk(trans, extent_root, flags);
4561 trans->allocating_chunk = false;
4562
4563 spin_lock(&space_info->lock);
4564 if (ret < 0 && ret != -ENOSPC)
4565 goto out;
4566 if (ret)
4567 space_info->full = 1;
4568 else
4569 ret = 1;
4570
4571 space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4572 out:
4573 space_info->chunk_alloc = 0;
4574 spin_unlock(&space_info->lock);
4575 mutex_unlock(&fs_info->chunk_mutex);
4576 /*
4577 * When we allocate a new chunk we reserve space in the chunk block
4578 * reserve to make sure we can COW nodes/leafs in the chunk tree or
4579 * add new nodes/leafs to it if we end up needing to do it when
4580 * inserting the chunk item and updating device items as part of the
4581 * second phase of chunk allocation, performed by
4582 * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
4583 * large number of new block groups to create in our transaction
4584 * handle's new_bgs list to avoid exhausting the chunk block reserve
4585 * in extreme cases - like having a single transaction create many new
4586 * block groups when starting to write out the free space caches of all
4587 * the block groups that were made dirty during the lifetime of the
4588 * transaction.
4589 */
4590 if (trans->can_flush_pending_bgs &&
4591 trans->chunk_bytes_reserved >= (u64)SZ_2M) {
4592 btrfs_create_pending_block_groups(trans, extent_root);
4593 btrfs_trans_release_chunk_metadata(trans);
4594 }
4595 return ret;
4596 }
4597
4598 static int can_overcommit(struct btrfs_root *root,
4599 struct btrfs_space_info *space_info, u64 bytes,
4600 enum btrfs_reserve_flush_enum flush)
4601 {
4602 struct btrfs_block_rsv *global_rsv;
4603 u64 profile;
4604 u64 space_size;
4605 u64 avail;
4606 u64 used;
4607
4608 /* Don't overcommit when in mixed mode. */
4609 if (space_info->flags & BTRFS_BLOCK_GROUP_DATA)
4610 return 0;
4611
4612 BUG_ON(root->fs_info == NULL);
4613 global_rsv = &root->fs_info->global_block_rsv;
4614 profile = btrfs_get_alloc_profile(root, 0);
4615 used = space_info->bytes_used + space_info->bytes_reserved +
4616 space_info->bytes_pinned + space_info->bytes_readonly;
4617
4618 /*
4619 * We only want to allow over committing if we have lots of actual space
4620 * free, but if we don't have enough space to handle the global reserve
4621 * space then we could end up having a real enospc problem when trying
4622 * to allocate a chunk or some other such important allocation.
4623 */
4624 spin_lock(&global_rsv->lock);
4625 space_size = calc_global_rsv_need_space(global_rsv);
4626 spin_unlock(&global_rsv->lock);
4627 if (used + space_size >= space_info->total_bytes)
4628 return 0;
4629
4630 used += space_info->bytes_may_use;
4631
4632 spin_lock(&root->fs_info->free_chunk_lock);
4633 avail = root->fs_info->free_chunk_space;
4634 spin_unlock(&root->fs_info->free_chunk_lock);
4635
4636 /*
4637 * If we have dup, raid1 or raid10 then only half of the free
4638 * space is actually useable. For raid56, the space info used
4639 * doesn't include the parity drive, so we don't have to
4640 * change the math
4641 */
4642 if (profile & (BTRFS_BLOCK_GROUP_DUP |
4643 BTRFS_BLOCK_GROUP_RAID1 |
4644 BTRFS_BLOCK_GROUP_RAID10))
4645 avail >>= 1;
4646
4647 /*
4648 * If we aren't flushing all things, let us overcommit up to
4649 * 1/2th of the space. If we can flush, don't let us overcommit
4650 * too much, let it overcommit up to 1/8 of the space.
4651 */
4652 if (flush == BTRFS_RESERVE_FLUSH_ALL)
4653 avail >>= 3;
4654 else
4655 avail >>= 1;
4656
4657 if (used + bytes < space_info->total_bytes + avail)
4658 return 1;
4659 return 0;
4660 }
4661
4662 static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
4663 unsigned long nr_pages, int nr_items)
4664 {
4665 struct super_block *sb = root->fs_info->sb;
4666
4667 if (down_read_trylock(&sb->s_umount)) {
4668 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
4669 up_read(&sb->s_umount);
4670 } else {
4671 /*
4672 * We needn't worry the filesystem going from r/w to r/o though
4673 * we don't acquire ->s_umount mutex, because the filesystem
4674 * should guarantee the delalloc inodes list be empty after
4675 * the filesystem is readonly(all dirty pages are written to
4676 * the disk).
4677 */
4678 btrfs_start_delalloc_roots(root->fs_info, 0, nr_items);
4679 if (!current->journal_info)
4680 btrfs_wait_ordered_roots(root->fs_info, nr_items,
4681 0, (u64)-1);
4682 }
4683 }
4684
4685 static inline int calc_reclaim_items_nr(struct btrfs_root *root, u64 to_reclaim)
4686 {
4687 u64 bytes;
4688 int nr;
4689
4690 bytes = btrfs_calc_trans_metadata_size(root, 1);
4691 nr = (int)div64_u64(to_reclaim, bytes);
4692 if (!nr)
4693 nr = 1;
4694 return nr;
4695 }
4696
4697 #define EXTENT_SIZE_PER_ITEM SZ_256K
4698
4699 /*
4700 * shrink metadata reservation for delalloc
4701 */
4702 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
4703 bool wait_ordered)
4704 {
4705 struct btrfs_block_rsv *block_rsv;
4706 struct btrfs_space_info *space_info;
4707 struct btrfs_trans_handle *trans;
4708 u64 delalloc_bytes;
4709 u64 max_reclaim;
4710 long time_left;
4711 unsigned long nr_pages;
4712 int loops;
4713 int items;
4714 enum btrfs_reserve_flush_enum flush;
4715
4716 /* Calc the number of the pages we need flush for space reservation */
4717 items = calc_reclaim_items_nr(root, to_reclaim);
4718 to_reclaim = (u64)items * EXTENT_SIZE_PER_ITEM;
4719
4720 trans = (struct btrfs_trans_handle *)current->journal_info;
4721 block_rsv = &root->fs_info->delalloc_block_rsv;
4722 space_info = block_rsv->space_info;
4723
4724 delalloc_bytes = percpu_counter_sum_positive(
4725 &root->fs_info->delalloc_bytes);
4726 if (delalloc_bytes == 0) {
4727 if (trans)
4728 return;
4729 if (wait_ordered)
4730 btrfs_wait_ordered_roots(root->fs_info, items,
4731 0, (u64)-1);
4732 return;
4733 }
4734
4735 loops = 0;
4736 while (delalloc_bytes && loops < 3) {
4737 max_reclaim = min(delalloc_bytes, to_reclaim);
4738 nr_pages = max_reclaim >> PAGE_SHIFT;
4739 btrfs_writeback_inodes_sb_nr(root, nr_pages, items);
4740 /*
4741 * We need to wait for the async pages to actually start before
4742 * we do anything.
4743 */
4744 max_reclaim = atomic_read(&root->fs_info->async_delalloc_pages);
4745 if (!max_reclaim)
4746 goto skip_async;
4747
4748 if (max_reclaim <= nr_pages)
4749 max_reclaim = 0;
4750 else
4751 max_reclaim -= nr_pages;
4752
4753 wait_event(root->fs_info->async_submit_wait,
4754 atomic_read(&root->fs_info->async_delalloc_pages) <=
4755 (int)max_reclaim);
4756 skip_async:
4757 if (!trans)
4758 flush = BTRFS_RESERVE_FLUSH_ALL;
4759 else
4760 flush = BTRFS_RESERVE_NO_FLUSH;
4761 spin_lock(&space_info->lock);
4762 if (can_overcommit(root, space_info, orig, flush)) {
4763 spin_unlock(&space_info->lock);
4764 break;
4765 }
4766 if (list_empty(&space_info->tickets) &&
4767 list_empty(&space_info->priority_tickets)) {
4768 spin_unlock(&space_info->lock);
4769 break;
4770 }
4771 spin_unlock(&space_info->lock);
4772
4773 loops++;
4774 if (wait_ordered && !trans) {
4775 btrfs_wait_ordered_roots(root->fs_info, items,
4776 0, (u64)-1);
4777 } else {
4778 time_left = schedule_timeout_killable(1);
4779 if (time_left)
4780 break;
4781 }
4782 delalloc_bytes = percpu_counter_sum_positive(
4783 &root->fs_info->delalloc_bytes);
4784 }
4785 }
4786
4787 /**
4788 * maybe_commit_transaction - possibly commit the transaction if its ok to
4789 * @root - the root we're allocating for
4790 * @bytes - the number of bytes we want to reserve
4791 * @force - force the commit
4792 *
4793 * This will check to make sure that committing the transaction will actually
4794 * get us somewhere and then commit the transaction if it does. Otherwise it
4795 * will return -ENOSPC.
4796 */
4797 static int may_commit_transaction(struct btrfs_root *root,
4798 struct btrfs_space_info *space_info,
4799 u64 bytes, int force)
4800 {
4801 struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
4802 struct btrfs_trans_handle *trans;
4803
4804 trans = (struct btrfs_trans_handle *)current->journal_info;
4805 if (trans)
4806 return -EAGAIN;
4807
4808 if (force)
4809 goto commit;
4810
4811 /* See if there is enough pinned space to make this reservation */
4812 if (percpu_counter_compare(&space_info->total_bytes_pinned,
4813 bytes) >= 0)
4814 goto commit;
4815
4816 /*
4817 * See if there is some space in the delayed insertion reservation for
4818 * this reservation.
4819 */
4820 if (space_info != delayed_rsv->space_info)
4821 return -ENOSPC;
4822
4823 spin_lock(&delayed_rsv->lock);
4824 if (percpu_counter_compare(&space_info->total_bytes_pinned,
4825 bytes - delayed_rsv->size) >= 0) {
4826 spin_unlock(&delayed_rsv->lock);
4827 return -ENOSPC;
4828 }
4829 spin_unlock(&delayed_rsv->lock);
4830
4831 commit:
4832 trans = btrfs_join_transaction(root);
4833 if (IS_ERR(trans))
4834 return -ENOSPC;
4835
4836 return btrfs_commit_transaction(trans, root);
4837 }
4838
4839 struct reserve_ticket {
4840 u64 bytes;
4841 int error;
4842 struct list_head list;
4843 wait_queue_head_t wait;
4844 };
4845
4846 static int flush_space(struct btrfs_root *root,
4847 struct btrfs_space_info *space_info, u64 num_bytes,
4848 u64 orig_bytes, int state)
4849 {
4850 struct btrfs_trans_handle *trans;
4851 int nr;
4852 int ret = 0;
4853
4854 switch (state) {
4855 case FLUSH_DELAYED_ITEMS_NR:
4856 case FLUSH_DELAYED_ITEMS:
4857 if (state == FLUSH_DELAYED_ITEMS_NR)
4858 nr = calc_reclaim_items_nr(root, num_bytes) * 2;
4859 else
4860 nr = -1;
4861
4862 trans = btrfs_join_transaction(root);
4863 if (IS_ERR(trans)) {
4864 ret = PTR_ERR(trans);
4865 break;
4866 }
4867 ret = btrfs_run_delayed_items_nr(trans, root, nr);
4868 btrfs_end_transaction(trans, root);
4869 break;
4870 case FLUSH_DELALLOC:
4871 case FLUSH_DELALLOC_WAIT:
4872 shrink_delalloc(root, num_bytes * 2, orig_bytes,
4873 state == FLUSH_DELALLOC_WAIT);
4874 break;
4875 case ALLOC_CHUNK:
4876 trans = btrfs_join_transaction(root);
4877 if (IS_ERR(trans)) {
4878 ret = PTR_ERR(trans);
4879 break;
4880 }
4881 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4882 btrfs_get_alloc_profile(root, 0),
4883 CHUNK_ALLOC_NO_FORCE);
4884 btrfs_end_transaction(trans, root);
4885 if (ret == -ENOSPC)
4886 ret = 0;
4887 break;
4888 case COMMIT_TRANS:
4889 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
4890 break;
4891 default:
4892 ret = -ENOSPC;
4893 break;
4894 }
4895
4896 trace_btrfs_flush_space(root->fs_info, space_info->flags, num_bytes,
4897 orig_bytes, state, ret);
4898 return ret;
4899 }
4900
4901 static inline u64
4902 btrfs_calc_reclaim_metadata_size(struct btrfs_root *root,
4903 struct btrfs_space_info *space_info)
4904 {
4905 struct reserve_ticket *ticket;
4906 u64 used;
4907 u64 expected;
4908 u64 to_reclaim = 0;
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 list_for_each_entry(ticket, &space_info->tickets, list)
4916 to_reclaim += ticket->bytes;
4917 list_for_each_entry(ticket, &space_info->priority_tickets, list)
4918 to_reclaim += ticket->bytes;
4919 if (to_reclaim)
4920 return to_reclaim;
4921
4922 used = space_info->bytes_used + space_info->bytes_reserved +
4923 space_info->bytes_pinned + space_info->bytes_readonly +
4924 space_info->bytes_may_use;
4925 if (can_overcommit(root, space_info, SZ_1M, BTRFS_RESERVE_FLUSH_ALL))
4926 expected = div_factor_fine(space_info->total_bytes, 95);
4927 else
4928 expected = div_factor_fine(space_info->total_bytes, 90);
4929
4930 if (used > expected)
4931 to_reclaim = used - expected;
4932 else
4933 to_reclaim = 0;
4934 to_reclaim = min(to_reclaim, space_info->bytes_may_use +
4935 space_info->bytes_reserved);
4936 return to_reclaim;
4937 }
4938
4939 static inline int need_do_async_reclaim(struct btrfs_space_info *space_info,
4940 struct btrfs_root *root, u64 used)
4941 {
4942 u64 thresh = div_factor_fine(space_info->total_bytes, 98);
4943
4944 /* If we're just plain full then async reclaim just slows us down. */
4945 if ((space_info->bytes_used + space_info->bytes_reserved) >= thresh)
4946 return 0;
4947
4948 if (!btrfs_calc_reclaim_metadata_size(root, space_info))
4949 return 0;
4950
4951 return (used >= thresh && !btrfs_fs_closing(root->fs_info) &&
4952 !test_bit(BTRFS_FS_STATE_REMOUNTING,
4953 &root->fs_info->fs_state));
4954 }
4955
4956 static void wake_all_tickets(struct list_head *head)
4957 {
4958 struct reserve_ticket *ticket;
4959
4960 while (!list_empty(head)) {
4961 ticket = list_first_entry(head, struct reserve_ticket, list);
4962 list_del_init(&ticket->list);
4963 ticket->error = -ENOSPC;
4964 wake_up(&ticket->wait);
4965 }
4966 }
4967
4968 /*
4969 * This is for normal flushers, we can wait all goddamned day if we want to. We
4970 * will loop and continuously try to flush as long as we are making progress.
4971 * We count progress as clearing off tickets each time we have to loop.
4972 */
4973 static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
4974 {
4975 struct reserve_ticket *last_ticket = NULL;
4976 struct btrfs_fs_info *fs_info;
4977 struct btrfs_space_info *space_info;
4978 u64 to_reclaim;
4979 int flush_state;
4980 int commit_cycles = 0;
4981
4982 fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
4983 space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4984
4985 spin_lock(&space_info->lock);
4986 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
4987 space_info);
4988 if (!to_reclaim) {
4989 space_info->flush = 0;
4990 spin_unlock(&space_info->lock);
4991 return;
4992 }
4993 last_ticket = list_first_entry(&space_info->tickets,
4994 struct reserve_ticket, list);
4995 spin_unlock(&space_info->lock);
4996
4997 flush_state = FLUSH_DELAYED_ITEMS_NR;
4998 do {
4999 struct reserve_ticket *ticket;
5000 int ret;
5001
5002 ret = flush_space(fs_info->fs_root, space_info, to_reclaim,
5003 to_reclaim, flush_state);
5004 spin_lock(&space_info->lock);
5005 if (list_empty(&space_info->tickets)) {
5006 space_info->flush = 0;
5007 spin_unlock(&space_info->lock);
5008 return;
5009 }
5010 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
5011 space_info);
5012 ticket = list_first_entry(&space_info->tickets,
5013 struct reserve_ticket, list);
5014 if (last_ticket == ticket) {
5015 flush_state++;
5016 } else {
5017 last_ticket = ticket;
5018 flush_state = FLUSH_DELAYED_ITEMS_NR;
5019 if (commit_cycles)
5020 commit_cycles--;
5021 }
5022
5023 if (flush_state > COMMIT_TRANS) {
5024 commit_cycles++;
5025 if (commit_cycles > 2) {
5026 wake_all_tickets(&space_info->tickets);
5027 space_info->flush = 0;
5028 } else {
5029 flush_state = FLUSH_DELAYED_ITEMS_NR;
5030 }
5031 }
5032 spin_unlock(&space_info->lock);
5033 } while (flush_state <= COMMIT_TRANS);
5034 }
5035
5036 void btrfs_init_async_reclaim_work(struct work_struct *work)
5037 {
5038 INIT_WORK(work, btrfs_async_reclaim_metadata_space);
5039 }
5040
5041 static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
5042 struct btrfs_space_info *space_info,
5043 struct reserve_ticket *ticket)
5044 {
5045 u64 to_reclaim;
5046 int flush_state = FLUSH_DELAYED_ITEMS_NR;
5047
5048 spin_lock(&space_info->lock);
5049 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
5050 space_info);
5051 if (!to_reclaim) {
5052 spin_unlock(&space_info->lock);
5053 return;
5054 }
5055 spin_unlock(&space_info->lock);
5056
5057 do {
5058 flush_space(fs_info->fs_root, space_info, to_reclaim,
5059 to_reclaim, flush_state);
5060 flush_state++;
5061 spin_lock(&space_info->lock);
5062 if (ticket->bytes == 0) {
5063 spin_unlock(&space_info->lock);
5064 return;
5065 }
5066 spin_unlock(&space_info->lock);
5067
5068 /*
5069 * Priority flushers can't wait on delalloc without
5070 * deadlocking.
5071 */
5072 if (flush_state == FLUSH_DELALLOC ||
5073 flush_state == FLUSH_DELALLOC_WAIT)
5074 flush_state = ALLOC_CHUNK;
5075 } while (flush_state < COMMIT_TRANS);
5076 }
5077
5078 static int wait_reserve_ticket(struct btrfs_fs_info *fs_info,
5079 struct btrfs_space_info *space_info,
5080 struct reserve_ticket *ticket, u64 orig_bytes)
5081
5082 {
5083 DEFINE_WAIT(wait);
5084 int ret = 0;
5085
5086 spin_lock(&space_info->lock);
5087 while (ticket->bytes > 0 && ticket->error == 0) {
5088 ret = prepare_to_wait_event(&ticket->wait, &wait, TASK_KILLABLE);
5089 if (ret) {
5090 ret = -EINTR;
5091 break;
5092 }
5093 spin_unlock(&space_info->lock);
5094
5095 schedule();
5096
5097 finish_wait(&ticket->wait, &wait);
5098 spin_lock(&space_info->lock);
5099 }
5100 if (!ret)
5101 ret = ticket->error;
5102 if (!list_empty(&ticket->list))
5103 list_del_init(&ticket->list);
5104 if (ticket->bytes && ticket->bytes < orig_bytes) {
5105 u64 num_bytes = orig_bytes - ticket->bytes;
5106 space_info->bytes_may_use -= num_bytes;
5107 trace_btrfs_space_reservation(fs_info, "space_info",
5108 space_info->flags, num_bytes, 0);
5109 }
5110 spin_unlock(&space_info->lock);
5111
5112 return ret;
5113 }
5114
5115 /**
5116 * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5117 * @root - the root we're allocating for
5118 * @space_info - the space info we want to allocate from
5119 * @orig_bytes - the number of bytes we want
5120 * @flush - whether or not we can flush to make our reservation
5121 *
5122 * This will reserve orig_bytes number of bytes from the space info associated
5123 * with the block_rsv. If there is not enough space it will make an attempt to
5124 * flush out space to make room. It will do this by flushing delalloc if
5125 * possible or committing the transaction. If flush is 0 then no attempts to
5126 * regain reservations will be made and this will fail if there is not enough
5127 * space already.
5128 */
5129 static int __reserve_metadata_bytes(struct btrfs_root *root,
5130 struct btrfs_space_info *space_info,
5131 u64 orig_bytes,
5132 enum btrfs_reserve_flush_enum flush)
5133 {
5134 struct reserve_ticket ticket;
5135 u64 used;
5136 int ret = 0;
5137
5138 ASSERT(orig_bytes);
5139 ASSERT(!current->journal_info || flush != BTRFS_RESERVE_FLUSH_ALL);
5140
5141 spin_lock(&space_info->lock);
5142 ret = -ENOSPC;
5143 used = space_info->bytes_used + space_info->bytes_reserved +
5144 space_info->bytes_pinned + space_info->bytes_readonly +
5145 space_info->bytes_may_use;
5146
5147 /*
5148 * If we have enough space then hooray, make our reservation and carry
5149 * on. If not see if we can overcommit, and if we can, hooray carry on.
5150 * If not things get more complicated.
5151 */
5152 if (used + orig_bytes <= space_info->total_bytes) {
5153 space_info->bytes_may_use += orig_bytes;
5154 trace_btrfs_space_reservation(root->fs_info, "space_info",
5155 space_info->flags, orig_bytes,
5156 1);
5157 ret = 0;
5158 } else if (can_overcommit(root, space_info, orig_bytes, flush)) {
5159 space_info->bytes_may_use += orig_bytes;
5160 trace_btrfs_space_reservation(root->fs_info, "space_info",
5161 space_info->flags, orig_bytes,
5162 1);
5163 ret = 0;
5164 }
5165
5166 /*
5167 * If we couldn't make a reservation then setup our reservation ticket
5168 * and kick the async worker if it's not already running.
5169 *
5170 * If we are a priority flusher then we just need to add our ticket to
5171 * the list and we will do our own flushing further down.
5172 */
5173 if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
5174 ticket.bytes = orig_bytes;
5175 ticket.error = 0;
5176 init_waitqueue_head(&ticket.wait);
5177 if (flush == BTRFS_RESERVE_FLUSH_ALL) {
5178 list_add_tail(&ticket.list, &space_info->tickets);
5179 if (!space_info->flush) {
5180 space_info->flush = 1;
5181 trace_btrfs_trigger_flush(root->fs_info,
5182 space_info->flags,
5183 orig_bytes, flush,
5184 "enospc");
5185 queue_work(system_unbound_wq,
5186 &root->fs_info->async_reclaim_work);
5187 }
5188 } else {
5189 list_add_tail(&ticket.list,
5190 &space_info->priority_tickets);
5191 }
5192 } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
5193 used += orig_bytes;
5194 /*
5195 * We will do the space reservation dance during log replay,
5196 * which means we won't have fs_info->fs_root set, so don't do
5197 * the async reclaim as we will panic.
5198 */
5199 if (!root->fs_info->log_root_recovering &&
5200 need_do_async_reclaim(space_info, root, used) &&
5201 !work_busy(&root->fs_info->async_reclaim_work)) {
5202 trace_btrfs_trigger_flush(root->fs_info,
5203 space_info->flags,
5204 orig_bytes, flush,
5205 "preempt");
5206 queue_work(system_unbound_wq,
5207 &root->fs_info->async_reclaim_work);
5208 }
5209 }
5210 spin_unlock(&space_info->lock);
5211 if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
5212 return ret;
5213
5214 if (flush == BTRFS_RESERVE_FLUSH_ALL)
5215 return wait_reserve_ticket(root->fs_info, space_info, &ticket,
5216 orig_bytes);
5217
5218 ret = 0;
5219 priority_reclaim_metadata_space(root->fs_info, space_info, &ticket);
5220 spin_lock(&space_info->lock);
5221 if (ticket.bytes) {
5222 if (ticket.bytes < orig_bytes) {
5223 u64 num_bytes = orig_bytes - ticket.bytes;
5224 space_info->bytes_may_use -= num_bytes;
5225 trace_btrfs_space_reservation(root->fs_info,
5226 "space_info", space_info->flags,
5227 num_bytes, 0);
5228
5229 }
5230 list_del_init(&ticket.list);
5231 ret = -ENOSPC;
5232 }
5233 spin_unlock(&space_info->lock);
5234 ASSERT(list_empty(&ticket.list));
5235 return ret;
5236 }
5237
5238 /**
5239 * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5240 * @root - the root we're allocating for
5241 * @block_rsv - the block_rsv we're allocating for
5242 * @orig_bytes - the number of bytes we want
5243 * @flush - whether or not we can flush to make our reservation
5244 *
5245 * This will reserve orgi_bytes number of bytes from the space info associated
5246 * with the block_rsv. If there is not enough space it will make an attempt to
5247 * flush out space to make room. It will do this by flushing delalloc if
5248 * possible or committing the transaction. If flush is 0 then no attempts to
5249 * regain reservations will be made and this will fail if there is not enough
5250 * space already.
5251 */
5252 static int reserve_metadata_bytes(struct btrfs_root *root,
5253 struct btrfs_block_rsv *block_rsv,
5254 u64 orig_bytes,
5255 enum btrfs_reserve_flush_enum flush)
5256 {
5257 int ret;
5258
5259 ret = __reserve_metadata_bytes(root, block_rsv->space_info, orig_bytes,
5260 flush);
5261 if (ret == -ENOSPC &&
5262 unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
5263 struct btrfs_block_rsv *global_rsv =
5264 &root->fs_info->global_block_rsv;
5265
5266 if (block_rsv != global_rsv &&
5267 !block_rsv_use_bytes(global_rsv, orig_bytes))
5268 ret = 0;
5269 }
5270 if (ret == -ENOSPC)
5271 trace_btrfs_space_reservation(root->fs_info,
5272 "space_info:enospc",
5273 block_rsv->space_info->flags,
5274 orig_bytes, 1);
5275 return ret;
5276 }
5277
5278 static struct btrfs_block_rsv *get_block_rsv(
5279 const struct btrfs_trans_handle *trans,
5280 const struct btrfs_root *root)
5281 {
5282 struct btrfs_block_rsv *block_rsv = NULL;
5283
5284 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
5285 (root == root->fs_info->csum_root && trans->adding_csums) ||
5286 (root == root->fs_info->uuid_root))
5287 block_rsv = trans->block_rsv;
5288
5289 if (!block_rsv)
5290 block_rsv = root->block_rsv;
5291
5292 if (!block_rsv)
5293 block_rsv = &root->fs_info->empty_block_rsv;
5294
5295 return block_rsv;
5296 }
5297
5298 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
5299 u64 num_bytes)
5300 {
5301 int ret = -ENOSPC;
5302 spin_lock(&block_rsv->lock);
5303 if (block_rsv->reserved >= num_bytes) {
5304 block_rsv->reserved -= num_bytes;
5305 if (block_rsv->reserved < block_rsv->size)
5306 block_rsv->full = 0;
5307 ret = 0;
5308 }
5309 spin_unlock(&block_rsv->lock);
5310 return ret;
5311 }
5312
5313 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
5314 u64 num_bytes, int update_size)
5315 {
5316 spin_lock(&block_rsv->lock);
5317 block_rsv->reserved += num_bytes;
5318 if (update_size)
5319 block_rsv->size += num_bytes;
5320 else if (block_rsv->reserved >= block_rsv->size)
5321 block_rsv->full = 1;
5322 spin_unlock(&block_rsv->lock);
5323 }
5324
5325 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
5326 struct btrfs_block_rsv *dest, u64 num_bytes,
5327 int min_factor)
5328 {
5329 struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5330 u64 min_bytes;
5331
5332 if (global_rsv->space_info != dest->space_info)
5333 return -ENOSPC;
5334
5335 spin_lock(&global_rsv->lock);
5336 min_bytes = div_factor(global_rsv->size, min_factor);
5337 if (global_rsv->reserved < min_bytes + num_bytes) {
5338 spin_unlock(&global_rsv->lock);
5339 return -ENOSPC;
5340 }
5341 global_rsv->reserved -= num_bytes;
5342 if (global_rsv->reserved < global_rsv->size)
5343 global_rsv->full = 0;
5344 spin_unlock(&global_rsv->lock);
5345
5346 block_rsv_add_bytes(dest, num_bytes, 1);
5347 return 0;
5348 }
5349
5350 /*
5351 * This is for space we already have accounted in space_info->bytes_may_use, so
5352 * basically when we're returning space from block_rsv's.
5353 */
5354 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
5355 struct btrfs_space_info *space_info,
5356 u64 num_bytes)
5357 {
5358 struct reserve_ticket *ticket;
5359 struct list_head *head;
5360 u64 used;
5361 enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_NO_FLUSH;
5362 bool check_overcommit = false;
5363
5364 spin_lock(&space_info->lock);
5365 head = &space_info->priority_tickets;
5366
5367 /*
5368 * If we are over our limit then we need to check and see if we can
5369 * overcommit, and if we can't then we just need to free up our space
5370 * and not satisfy any requests.
5371 */
5372 used = space_info->bytes_used + space_info->bytes_reserved +
5373 space_info->bytes_pinned + space_info->bytes_readonly +
5374 space_info->bytes_may_use;
5375 if (used - num_bytes >= space_info->total_bytes)
5376 check_overcommit = true;
5377 again:
5378 while (!list_empty(head) && num_bytes) {
5379 ticket = list_first_entry(head, struct reserve_ticket,
5380 list);
5381 /*
5382 * We use 0 bytes because this space is already reserved, so
5383 * adding the ticket space would be a double count.
5384 */
5385 if (check_overcommit &&
5386 !can_overcommit(fs_info->extent_root, space_info, 0,
5387 flush))
5388 break;
5389 if (num_bytes >= ticket->bytes) {
5390 list_del_init(&ticket->list);
5391 num_bytes -= ticket->bytes;
5392 ticket->bytes = 0;
5393 wake_up(&ticket->wait);
5394 } else {
5395 ticket->bytes -= num_bytes;
5396 num_bytes = 0;
5397 }
5398 }
5399
5400 if (num_bytes && head == &space_info->priority_tickets) {
5401 head = &space_info->tickets;
5402 flush = BTRFS_RESERVE_FLUSH_ALL;
5403 goto again;
5404 }
5405 space_info->bytes_may_use -= num_bytes;
5406 trace_btrfs_space_reservation(fs_info, "space_info",
5407 space_info->flags, num_bytes, 0);
5408 spin_unlock(&space_info->lock);
5409 }
5410
5411 /*
5412 * This is for newly allocated space that isn't accounted in
5413 * space_info->bytes_may_use yet. So if we allocate a chunk or unpin an extent
5414 * we use this helper.
5415 */
5416 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
5417 struct btrfs_space_info *space_info,
5418 u64 num_bytes)
5419 {
5420 struct reserve_ticket *ticket;
5421 struct list_head *head = &space_info->priority_tickets;
5422
5423 again:
5424 while (!list_empty(head) && num_bytes) {
5425 ticket = list_first_entry(head, struct reserve_ticket,
5426 list);
5427 if (num_bytes >= ticket->bytes) {
5428 trace_btrfs_space_reservation(fs_info, "space_info",
5429 space_info->flags,
5430 ticket->bytes, 1);
5431 list_del_init(&ticket->list);
5432 num_bytes -= ticket->bytes;
5433 space_info->bytes_may_use += ticket->bytes;
5434 ticket->bytes = 0;
5435 wake_up(&ticket->wait);
5436 } else {
5437 trace_btrfs_space_reservation(fs_info, "space_info",
5438 space_info->flags,
5439 num_bytes, 1);
5440 space_info->bytes_may_use += num_bytes;
5441 ticket->bytes -= num_bytes;
5442 num_bytes = 0;
5443 }
5444 }
5445
5446 if (num_bytes && head == &space_info->priority_tickets) {
5447 head = &space_info->tickets;
5448 goto again;
5449 }
5450 }
5451
5452 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
5453 struct btrfs_block_rsv *block_rsv,
5454 struct btrfs_block_rsv *dest, u64 num_bytes)
5455 {
5456 struct btrfs_space_info *space_info = block_rsv->space_info;
5457
5458 spin_lock(&block_rsv->lock);
5459 if (num_bytes == (u64)-1)
5460 num_bytes = block_rsv->size;
5461 block_rsv->size -= num_bytes;
5462 if (block_rsv->reserved >= block_rsv->size) {
5463 num_bytes = block_rsv->reserved - block_rsv->size;
5464 block_rsv->reserved = block_rsv->size;
5465 block_rsv->full = 1;
5466 } else {
5467 num_bytes = 0;
5468 }
5469 spin_unlock(&block_rsv->lock);
5470
5471 if (num_bytes > 0) {
5472 if (dest) {
5473 spin_lock(&dest->lock);
5474 if (!dest->full) {
5475 u64 bytes_to_add;
5476
5477 bytes_to_add = dest->size - dest->reserved;
5478 bytes_to_add = min(num_bytes, bytes_to_add);
5479 dest->reserved += bytes_to_add;
5480 if (dest->reserved >= dest->size)
5481 dest->full = 1;
5482 num_bytes -= bytes_to_add;
5483 }
5484 spin_unlock(&dest->lock);
5485 }
5486 if (num_bytes)
5487 space_info_add_old_bytes(fs_info, space_info,
5488 num_bytes);
5489 }
5490 }
5491
5492 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src,
5493 struct btrfs_block_rsv *dst, u64 num_bytes,
5494 int update_size)
5495 {
5496 int ret;
5497
5498 ret = block_rsv_use_bytes(src, num_bytes);
5499 if (ret)
5500 return ret;
5501
5502 block_rsv_add_bytes(dst, num_bytes, update_size);
5503 return 0;
5504 }
5505
5506 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
5507 {
5508 memset(rsv, 0, sizeof(*rsv));
5509 spin_lock_init(&rsv->lock);
5510 rsv->type = type;
5511 }
5512
5513 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
5514 unsigned short type)
5515 {
5516 struct btrfs_block_rsv *block_rsv;
5517 struct btrfs_fs_info *fs_info = root->fs_info;
5518
5519 block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
5520 if (!block_rsv)
5521 return NULL;
5522
5523 btrfs_init_block_rsv(block_rsv, type);
5524 block_rsv->space_info = __find_space_info(fs_info,
5525 BTRFS_BLOCK_GROUP_METADATA);
5526 return block_rsv;
5527 }
5528
5529 void btrfs_free_block_rsv(struct btrfs_root *root,
5530 struct btrfs_block_rsv *rsv)
5531 {
5532 if (!rsv)
5533 return;
5534 btrfs_block_rsv_release(root, rsv, (u64)-1);
5535 kfree(rsv);
5536 }
5537
5538 void __btrfs_free_block_rsv(struct btrfs_block_rsv *rsv)
5539 {
5540 kfree(rsv);
5541 }
5542
5543 int btrfs_block_rsv_add(struct btrfs_root *root,
5544 struct btrfs_block_rsv *block_rsv, u64 num_bytes,
5545 enum btrfs_reserve_flush_enum flush)
5546 {
5547 int ret;
5548
5549 if (num_bytes == 0)
5550 return 0;
5551
5552 ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5553 if (!ret) {
5554 block_rsv_add_bytes(block_rsv, num_bytes, 1);
5555 return 0;
5556 }
5557
5558 return ret;
5559 }
5560
5561 int btrfs_block_rsv_check(struct btrfs_root *root,
5562 struct btrfs_block_rsv *block_rsv, int min_factor)
5563 {
5564 u64 num_bytes = 0;
5565 int ret = -ENOSPC;
5566
5567 if (!block_rsv)
5568 return 0;
5569
5570 spin_lock(&block_rsv->lock);
5571 num_bytes = div_factor(block_rsv->size, min_factor);
5572 if (block_rsv->reserved >= num_bytes)
5573 ret = 0;
5574 spin_unlock(&block_rsv->lock);
5575
5576 return ret;
5577 }
5578
5579 int btrfs_block_rsv_refill(struct btrfs_root *root,
5580 struct btrfs_block_rsv *block_rsv, u64 min_reserved,
5581 enum btrfs_reserve_flush_enum flush)
5582 {
5583 u64 num_bytes = 0;
5584 int ret = -ENOSPC;
5585
5586 if (!block_rsv)
5587 return 0;
5588
5589 spin_lock(&block_rsv->lock);
5590 num_bytes = min_reserved;
5591 if (block_rsv->reserved >= num_bytes)
5592 ret = 0;
5593 else
5594 num_bytes -= block_rsv->reserved;
5595 spin_unlock(&block_rsv->lock);
5596
5597 if (!ret)
5598 return 0;
5599
5600 ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5601 if (!ret) {
5602 block_rsv_add_bytes(block_rsv, num_bytes, 0);
5603 return 0;
5604 }
5605
5606 return ret;
5607 }
5608
5609 void btrfs_block_rsv_release(struct btrfs_root *root,
5610 struct btrfs_block_rsv *block_rsv,
5611 u64 num_bytes)
5612 {
5613 struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5614 if (global_rsv == block_rsv ||
5615 block_rsv->space_info != global_rsv->space_info)
5616 global_rsv = NULL;
5617 block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
5618 num_bytes);
5619 }
5620
5621 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
5622 {
5623 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
5624 struct btrfs_space_info *sinfo = block_rsv->space_info;
5625 u64 num_bytes;
5626
5627 /*
5628 * The global block rsv is based on the size of the extent tree, the
5629 * checksum tree and the root tree. If the fs is empty we want to set
5630 * it to a minimal amount for safety.
5631 */
5632 num_bytes = btrfs_root_used(&fs_info->extent_root->root_item) +
5633 btrfs_root_used(&fs_info->csum_root->root_item) +
5634 btrfs_root_used(&fs_info->tree_root->root_item);
5635 num_bytes = max_t(u64, num_bytes, SZ_16M);
5636
5637 spin_lock(&sinfo->lock);
5638 spin_lock(&block_rsv->lock);
5639
5640 block_rsv->size = min_t(u64, num_bytes, SZ_512M);
5641
5642 if (block_rsv->reserved < block_rsv->size) {
5643 num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
5644 sinfo->bytes_reserved + sinfo->bytes_readonly +
5645 sinfo->bytes_may_use;
5646 if (sinfo->total_bytes > num_bytes) {
5647 num_bytes = sinfo->total_bytes - num_bytes;
5648 num_bytes = min(num_bytes,
5649 block_rsv->size - block_rsv->reserved);
5650 block_rsv->reserved += num_bytes;
5651 sinfo->bytes_may_use += num_bytes;
5652 trace_btrfs_space_reservation(fs_info, "space_info",
5653 sinfo->flags, num_bytes,
5654 1);
5655 }
5656 } else if (block_rsv->reserved > block_rsv->size) {
5657 num_bytes = block_rsv->reserved - block_rsv->size;
5658 sinfo->bytes_may_use -= num_bytes;
5659 trace_btrfs_space_reservation(fs_info, "space_info",
5660 sinfo->flags, num_bytes, 0);
5661 block_rsv->reserved = block_rsv->size;
5662 }
5663
5664 if (block_rsv->reserved == block_rsv->size)
5665 block_rsv->full = 1;
5666 else
5667 block_rsv->full = 0;
5668
5669 spin_unlock(&block_rsv->lock);
5670 spin_unlock(&sinfo->lock);
5671 }
5672
5673 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
5674 {
5675 struct btrfs_space_info *space_info;
5676
5677 space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
5678 fs_info->chunk_block_rsv.space_info = space_info;
5679
5680 space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5681 fs_info->global_block_rsv.space_info = space_info;
5682 fs_info->delalloc_block_rsv.space_info = space_info;
5683 fs_info->trans_block_rsv.space_info = space_info;
5684 fs_info->empty_block_rsv.space_info = space_info;
5685 fs_info->delayed_block_rsv.space_info = space_info;
5686
5687 fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
5688 fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
5689 fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
5690 fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
5691 if (fs_info->quota_root)
5692 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
5693 fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
5694
5695 update_global_block_rsv(fs_info);
5696 }
5697
5698 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
5699 {
5700 block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
5701 (u64)-1);
5702 WARN_ON(fs_info->delalloc_block_rsv.size > 0);
5703 WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
5704 WARN_ON(fs_info->trans_block_rsv.size > 0);
5705 WARN_ON(fs_info->trans_block_rsv.reserved > 0);
5706 WARN_ON(fs_info->chunk_block_rsv.size > 0);
5707 WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
5708 WARN_ON(fs_info->delayed_block_rsv.size > 0);
5709 WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
5710 }
5711
5712 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
5713 struct btrfs_root *root)
5714 {
5715 if (!trans->block_rsv)
5716 return;
5717
5718 if (!trans->bytes_reserved)
5719 return;
5720
5721 trace_btrfs_space_reservation(root->fs_info, "transaction",
5722 trans->transid, trans->bytes_reserved, 0);
5723 btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
5724 trans->bytes_reserved = 0;
5725 }
5726
5727 /*
5728 * To be called after all the new block groups attached to the transaction
5729 * handle have been created (btrfs_create_pending_block_groups()).
5730 */
5731 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
5732 {
5733 struct btrfs_fs_info *fs_info = trans->fs_info;
5734
5735 if (!trans->chunk_bytes_reserved)
5736 return;
5737
5738 WARN_ON_ONCE(!list_empty(&trans->new_bgs));
5739
5740 block_rsv_release_bytes(fs_info, &fs_info->chunk_block_rsv, NULL,
5741 trans->chunk_bytes_reserved);
5742 trans->chunk_bytes_reserved = 0;
5743 }
5744
5745 /* Can only return 0 or -ENOSPC */
5746 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
5747 struct inode *inode)
5748 {
5749 struct btrfs_root *root = BTRFS_I(inode)->root;
5750 /*
5751 * We always use trans->block_rsv here as we will have reserved space
5752 * for our orphan when starting the transaction, using get_block_rsv()
5753 * here will sometimes make us choose the wrong block rsv as we could be
5754 * doing a reloc inode for a non refcounted root.
5755 */
5756 struct btrfs_block_rsv *src_rsv = trans->block_rsv;
5757 struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
5758
5759 /*
5760 * We need to hold space in order to delete our orphan item once we've
5761 * added it, so this takes the reservation so we can release it later
5762 * when we are truly done with the orphan item.
5763 */
5764 u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5765 trace_btrfs_space_reservation(root->fs_info, "orphan",
5766 btrfs_ino(inode), num_bytes, 1);
5767 return btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes, 1);
5768 }
5769
5770 void btrfs_orphan_release_metadata(struct inode *inode)
5771 {
5772 struct btrfs_root *root = BTRFS_I(inode)->root;
5773 u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5774 trace_btrfs_space_reservation(root->fs_info, "orphan",
5775 btrfs_ino(inode), num_bytes, 0);
5776 btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
5777 }
5778
5779 /*
5780 * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
5781 * root: the root of the parent directory
5782 * rsv: block reservation
5783 * items: the number of items that we need do reservation
5784 * qgroup_reserved: used to return the reserved size in qgroup
5785 *
5786 * This function is used to reserve the space for snapshot/subvolume
5787 * creation and deletion. Those operations are different with the
5788 * common file/directory operations, they change two fs/file trees
5789 * and root tree, the number of items that the qgroup reserves is
5790 * different with the free space reservation. So we can not use
5791 * the space reservation mechanism in start_transaction().
5792 */
5793 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
5794 struct btrfs_block_rsv *rsv,
5795 int items,
5796 u64 *qgroup_reserved,
5797 bool use_global_rsv)
5798 {
5799 u64 num_bytes;
5800 int ret;
5801 struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5802
5803 if (root->fs_info->quota_enabled) {
5804 /* One for parent inode, two for dir entries */
5805 num_bytes = 3 * root->nodesize;
5806 ret = btrfs_qgroup_reserve_meta(root, num_bytes);
5807 if (ret)
5808 return ret;
5809 } else {
5810 num_bytes = 0;
5811 }
5812
5813 *qgroup_reserved = num_bytes;
5814
5815 num_bytes = btrfs_calc_trans_metadata_size(root, items);
5816 rsv->space_info = __find_space_info(root->fs_info,
5817 BTRFS_BLOCK_GROUP_METADATA);
5818 ret = btrfs_block_rsv_add(root, rsv, num_bytes,
5819 BTRFS_RESERVE_FLUSH_ALL);
5820
5821 if (ret == -ENOSPC && use_global_rsv)
5822 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes, 1);
5823
5824 if (ret && *qgroup_reserved)
5825 btrfs_qgroup_free_meta(root, *qgroup_reserved);
5826
5827 return ret;
5828 }
5829
5830 void btrfs_subvolume_release_metadata(struct btrfs_root *root,
5831 struct btrfs_block_rsv *rsv,
5832 u64 qgroup_reserved)
5833 {
5834 btrfs_block_rsv_release(root, rsv, (u64)-1);
5835 }
5836
5837 /**
5838 * drop_outstanding_extent - drop an outstanding extent
5839 * @inode: the inode we're dropping the extent for
5840 * @num_bytes: the number of bytes we're releasing.
5841 *
5842 * This is called when we are freeing up an outstanding extent, either called
5843 * after an error or after an extent is written. This will return the number of
5844 * reserved extents that need to be freed. This must be called with
5845 * BTRFS_I(inode)->lock held.
5846 */
5847 static unsigned drop_outstanding_extent(struct inode *inode, u64 num_bytes)
5848 {
5849 unsigned drop_inode_space = 0;
5850 unsigned dropped_extents = 0;
5851 unsigned num_extents = 0;
5852
5853 num_extents = (unsigned)div64_u64(num_bytes +
5854 BTRFS_MAX_EXTENT_SIZE - 1,
5855 BTRFS_MAX_EXTENT_SIZE);
5856 ASSERT(num_extents);
5857 ASSERT(BTRFS_I(inode)->outstanding_extents >= num_extents);
5858 BTRFS_I(inode)->outstanding_extents -= num_extents;
5859
5860 if (BTRFS_I(inode)->outstanding_extents == 0 &&
5861 test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5862 &BTRFS_I(inode)->runtime_flags))
5863 drop_inode_space = 1;
5864
5865 /*
5866 * If we have more or the same amount of outstanding extents than we have
5867 * reserved then we need to leave the reserved extents count alone.
5868 */
5869 if (BTRFS_I(inode)->outstanding_extents >=
5870 BTRFS_I(inode)->reserved_extents)
5871 return drop_inode_space;
5872
5873 dropped_extents = BTRFS_I(inode)->reserved_extents -
5874 BTRFS_I(inode)->outstanding_extents;
5875 BTRFS_I(inode)->reserved_extents -= dropped_extents;
5876 return dropped_extents + drop_inode_space;
5877 }
5878
5879 /**
5880 * calc_csum_metadata_size - return the amount of metadata space that must be
5881 * reserved/freed for the given bytes.
5882 * @inode: the inode we're manipulating
5883 * @num_bytes: the number of bytes in question
5884 * @reserve: 1 if we are reserving space, 0 if we are freeing space
5885 *
5886 * This adjusts the number of csum_bytes in the inode and then returns the
5887 * correct amount of metadata that must either be reserved or freed. We
5888 * calculate how many checksums we can fit into one leaf and then divide the
5889 * number of bytes that will need to be checksumed by this value to figure out
5890 * how many checksums will be required. If we are adding bytes then the number
5891 * may go up and we will return the number of additional bytes that must be
5892 * reserved. If it is going down we will return the number of bytes that must
5893 * be freed.
5894 *
5895 * This must be called with BTRFS_I(inode)->lock held.
5896 */
5897 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
5898 int reserve)
5899 {
5900 struct btrfs_root *root = BTRFS_I(inode)->root;
5901 u64 old_csums, num_csums;
5902
5903 if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
5904 BTRFS_I(inode)->csum_bytes == 0)
5905 return 0;
5906
5907 old_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5908 if (reserve)
5909 BTRFS_I(inode)->csum_bytes += num_bytes;
5910 else
5911 BTRFS_I(inode)->csum_bytes -= num_bytes;
5912 num_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5913
5914 /* No change, no need to reserve more */
5915 if (old_csums == num_csums)
5916 return 0;
5917
5918 if (reserve)
5919 return btrfs_calc_trans_metadata_size(root,
5920 num_csums - old_csums);
5921
5922 return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
5923 }
5924
5925 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
5926 {
5927 struct btrfs_root *root = BTRFS_I(inode)->root;
5928 struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
5929 u64 to_reserve = 0;
5930 u64 csum_bytes;
5931 unsigned nr_extents = 0;
5932 enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
5933 int ret = 0;
5934 bool delalloc_lock = true;
5935 u64 to_free = 0;
5936 unsigned dropped;
5937 bool release_extra = false;
5938
5939 /* If we are a free space inode we need to not flush since we will be in
5940 * the middle of a transaction commit. We also don't need the delalloc
5941 * mutex since we won't race with anybody. We need this mostly to make
5942 * lockdep shut its filthy mouth.
5943 *
5944 * If we have a transaction open (can happen if we call truncate_block
5945 * from truncate), then we need FLUSH_LIMIT so we don't deadlock.
5946 */
5947 if (btrfs_is_free_space_inode(inode)) {
5948 flush = BTRFS_RESERVE_NO_FLUSH;
5949 delalloc_lock = false;
5950 } else if (current->journal_info) {
5951 flush = BTRFS_RESERVE_FLUSH_LIMIT;
5952 }
5953
5954 if (flush != BTRFS_RESERVE_NO_FLUSH &&
5955 btrfs_transaction_in_commit(root->fs_info))
5956 schedule_timeout(1);
5957
5958 if (delalloc_lock)
5959 mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
5960
5961 num_bytes = ALIGN(num_bytes, root->sectorsize);
5962
5963 spin_lock(&BTRFS_I(inode)->lock);
5964 nr_extents = (unsigned)div64_u64(num_bytes +
5965 BTRFS_MAX_EXTENT_SIZE - 1,
5966 BTRFS_MAX_EXTENT_SIZE);
5967 BTRFS_I(inode)->outstanding_extents += nr_extents;
5968
5969 nr_extents = 0;
5970 if (BTRFS_I(inode)->outstanding_extents >
5971 BTRFS_I(inode)->reserved_extents)
5972 nr_extents += BTRFS_I(inode)->outstanding_extents -
5973 BTRFS_I(inode)->reserved_extents;
5974
5975 /* We always want to reserve a slot for updating the inode. */
5976 to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents + 1);
5977 to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
5978 csum_bytes = BTRFS_I(inode)->csum_bytes;
5979 spin_unlock(&BTRFS_I(inode)->lock);
5980
5981 if (root->fs_info->quota_enabled) {
5982 ret = btrfs_qgroup_reserve_meta(root,
5983 nr_extents * root->nodesize);
5984 if (ret)
5985 goto out_fail;
5986 }
5987
5988 ret = btrfs_block_rsv_add(root, block_rsv, to_reserve, flush);
5989 if (unlikely(ret)) {
5990 btrfs_qgroup_free_meta(root, nr_extents * root->nodesize);
5991 goto out_fail;
5992 }
5993
5994 spin_lock(&BTRFS_I(inode)->lock);
5995 if (test_and_set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5996 &BTRFS_I(inode)->runtime_flags)) {
5997 to_reserve -= btrfs_calc_trans_metadata_size(root, 1);
5998 release_extra = true;
5999 }
6000 BTRFS_I(inode)->reserved_extents += nr_extents;
6001 spin_unlock(&BTRFS_I(inode)->lock);
6002
6003 if (delalloc_lock)
6004 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
6005
6006 if (to_reserve)
6007 trace_btrfs_space_reservation(root->fs_info, "delalloc",
6008 btrfs_ino(inode), to_reserve, 1);
6009 if (release_extra)
6010 btrfs_block_rsv_release(root, block_rsv,
6011 btrfs_calc_trans_metadata_size(root,
6012 1));
6013 return 0;
6014
6015 out_fail:
6016 spin_lock(&BTRFS_I(inode)->lock);
6017 dropped = drop_outstanding_extent(inode, num_bytes);
6018 /*
6019 * If the inodes csum_bytes is the same as the original
6020 * csum_bytes then we know we haven't raced with any free()ers
6021 * so we can just reduce our inodes csum bytes and carry on.
6022 */
6023 if (BTRFS_I(inode)->csum_bytes == csum_bytes) {
6024 calc_csum_metadata_size(inode, num_bytes, 0);
6025 } else {
6026 u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes;
6027 u64 bytes;
6028
6029 /*
6030 * This is tricky, but first we need to figure out how much we
6031 * freed from any free-ers that occurred during this
6032 * reservation, so we reset ->csum_bytes to the csum_bytes
6033 * before we dropped our lock, and then call the free for the
6034 * number of bytes that were freed while we were trying our
6035 * reservation.
6036 */
6037 bytes = csum_bytes - BTRFS_I(inode)->csum_bytes;
6038 BTRFS_I(inode)->csum_bytes = csum_bytes;
6039 to_free = calc_csum_metadata_size(inode, bytes, 0);
6040
6041
6042 /*
6043 * Now we need to see how much we would have freed had we not
6044 * been making this reservation and our ->csum_bytes were not
6045 * artificially inflated.
6046 */
6047 BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes;
6048 bytes = csum_bytes - orig_csum_bytes;
6049 bytes = calc_csum_metadata_size(inode, bytes, 0);
6050
6051 /*
6052 * Now reset ->csum_bytes to what it should be. If bytes is
6053 * more than to_free then we would have freed more space had we
6054 * not had an artificially high ->csum_bytes, so we need to free
6055 * the remainder. If bytes is the same or less then we don't
6056 * need to do anything, the other free-ers did the correct
6057 * thing.
6058 */
6059 BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes;
6060 if (bytes > to_free)
6061 to_free = bytes - to_free;
6062 else
6063 to_free = 0;
6064 }
6065 spin_unlock(&BTRFS_I(inode)->lock);
6066 if (dropped)
6067 to_free += btrfs_calc_trans_metadata_size(root, dropped);
6068
6069 if (to_free) {
6070 btrfs_block_rsv_release(root, block_rsv, to_free);
6071 trace_btrfs_space_reservation(root->fs_info, "delalloc",
6072 btrfs_ino(inode), to_free, 0);
6073 }
6074 if (delalloc_lock)
6075 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
6076 return ret;
6077 }
6078
6079 /**
6080 * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
6081 * @inode: the inode to release the reservation for
6082 * @num_bytes: the number of bytes we're releasing
6083 *
6084 * This will release the metadata reservation for an inode. This can be called
6085 * once we complete IO for a given set of bytes to release their metadata
6086 * reservations.
6087 */
6088 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
6089 {
6090 struct btrfs_root *root = BTRFS_I(inode)->root;
6091 u64 to_free = 0;
6092 unsigned dropped;
6093
6094 num_bytes = ALIGN(num_bytes, root->sectorsize);
6095 spin_lock(&BTRFS_I(inode)->lock);
6096 dropped = drop_outstanding_extent(inode, num_bytes);
6097
6098 if (num_bytes)
6099 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
6100 spin_unlock(&BTRFS_I(inode)->lock);
6101 if (dropped > 0)
6102 to_free += btrfs_calc_trans_metadata_size(root, dropped);
6103
6104 if (btrfs_is_testing(root->fs_info))
6105 return;
6106
6107 trace_btrfs_space_reservation(root->fs_info, "delalloc",
6108 btrfs_ino(inode), to_free, 0);
6109
6110 btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
6111 to_free);
6112 }
6113
6114 /**
6115 * btrfs_delalloc_reserve_space - reserve data and metadata space for
6116 * delalloc
6117 * @inode: inode we're writing to
6118 * @start: start range we are writing to
6119 * @len: how long the range we are writing to
6120 *
6121 * TODO: This function will finally replace old btrfs_delalloc_reserve_space()
6122 *
6123 * This will do the following things
6124 *
6125 * o reserve space in data space info for num bytes
6126 * and reserve precious corresponding qgroup space
6127 * (Done in check_data_free_space)
6128 *
6129 * o reserve space for metadata space, based on the number of outstanding
6130 * extents and how much csums will be needed
6131 * also reserve metadata space in a per root over-reserve method.
6132 * o add to the inodes->delalloc_bytes
6133 * o add it to the fs_info's delalloc inodes list.
6134 * (Above 3 all done in delalloc_reserve_metadata)
6135 *
6136 * Return 0 for success
6137 * Return <0 for error(-ENOSPC or -EQUOT)
6138 */
6139 int btrfs_delalloc_reserve_space(struct inode *inode, u64 start, u64 len)
6140 {
6141 int ret;
6142
6143 ret = btrfs_check_data_free_space(inode, start, len);
6144 if (ret < 0)
6145 return ret;
6146 ret = btrfs_delalloc_reserve_metadata(inode, len);
6147 if (ret < 0)
6148 btrfs_free_reserved_data_space(inode, start, len);
6149 return ret;
6150 }
6151
6152 /**
6153 * btrfs_delalloc_release_space - release data and metadata space for delalloc
6154 * @inode: inode we're releasing space for
6155 * @start: start position of the space already reserved
6156 * @len: the len of the space already reserved
6157 *
6158 * This must be matched with a call to btrfs_delalloc_reserve_space. This is
6159 * called in the case that we don't need the metadata AND data reservations
6160 * anymore. So if there is an error or we insert an inline extent.
6161 *
6162 * This function will release the metadata space that was not used and will
6163 * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
6164 * list if there are no delalloc bytes left.
6165 * Also it will handle the qgroup reserved space.
6166 */
6167 void btrfs_delalloc_release_space(struct inode *inode, u64 start, u64 len)
6168 {
6169 btrfs_delalloc_release_metadata(inode, len);
6170 btrfs_free_reserved_data_space(inode, start, len);
6171 }
6172
6173 static int update_block_group(struct btrfs_trans_handle *trans,
6174 struct btrfs_root *root, u64 bytenr,
6175 u64 num_bytes, int alloc)
6176 {
6177 struct btrfs_block_group_cache *cache = NULL;
6178 struct btrfs_fs_info *info = root->fs_info;
6179 u64 total = num_bytes;
6180 u64 old_val;
6181 u64 byte_in_group;
6182 int factor;
6183
6184 /* block accounting for super block */
6185 spin_lock(&info->delalloc_root_lock);
6186 old_val = btrfs_super_bytes_used(info->super_copy);
6187 if (alloc)
6188 old_val += num_bytes;
6189 else
6190 old_val -= num_bytes;
6191 btrfs_set_super_bytes_used(info->super_copy, old_val);
6192 spin_unlock(&info->delalloc_root_lock);
6193
6194 while (total) {
6195 cache = btrfs_lookup_block_group(info, bytenr);
6196 if (!cache)
6197 return -ENOENT;
6198 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
6199 BTRFS_BLOCK_GROUP_RAID1 |
6200 BTRFS_BLOCK_GROUP_RAID10))
6201 factor = 2;
6202 else
6203 factor = 1;
6204 /*
6205 * If this block group has free space cache written out, we
6206 * need to make sure to load it if we are removing space. This
6207 * is because we need the unpinning stage to actually add the
6208 * space back to the block group, otherwise we will leak space.
6209 */
6210 if (!alloc && cache->cached == BTRFS_CACHE_NO)
6211 cache_block_group(cache, 1);
6212
6213 byte_in_group = bytenr - cache->key.objectid;
6214 WARN_ON(byte_in_group > cache->key.offset);
6215
6216 spin_lock(&cache->space_info->lock);
6217 spin_lock(&cache->lock);
6218
6219 if (btrfs_test_opt(root->fs_info, SPACE_CACHE) &&
6220 cache->disk_cache_state < BTRFS_DC_CLEAR)
6221 cache->disk_cache_state = BTRFS_DC_CLEAR;
6222
6223 old_val = btrfs_block_group_used(&cache->item);
6224 num_bytes = min(total, cache->key.offset - byte_in_group);
6225 if (alloc) {
6226 old_val += num_bytes;
6227 btrfs_set_block_group_used(&cache->item, old_val);
6228 cache->reserved -= num_bytes;
6229 cache->space_info->bytes_reserved -= num_bytes;
6230 cache->space_info->bytes_used += num_bytes;
6231 cache->space_info->disk_used += num_bytes * factor;
6232 spin_unlock(&cache->lock);
6233 spin_unlock(&cache->space_info->lock);
6234 } else {
6235 old_val -= num_bytes;
6236 btrfs_set_block_group_used(&cache->item, old_val);
6237 cache->pinned += num_bytes;
6238 cache->space_info->bytes_pinned += num_bytes;
6239 cache->space_info->bytes_used -= num_bytes;
6240 cache->space_info->disk_used -= num_bytes * factor;
6241 spin_unlock(&cache->lock);
6242 spin_unlock(&cache->space_info->lock);
6243
6244 trace_btrfs_space_reservation(root->fs_info, "pinned",
6245 cache->space_info->flags,
6246 num_bytes, 1);
6247 set_extent_dirty(info->pinned_extents,
6248 bytenr, bytenr + num_bytes - 1,
6249 GFP_NOFS | __GFP_NOFAIL);
6250 }
6251
6252 spin_lock(&trans->transaction->dirty_bgs_lock);
6253 if (list_empty(&cache->dirty_list)) {
6254 list_add_tail(&cache->dirty_list,
6255 &trans->transaction->dirty_bgs);
6256 trans->transaction->num_dirty_bgs++;
6257 btrfs_get_block_group(cache);
6258 }
6259 spin_unlock(&trans->transaction->dirty_bgs_lock);
6260
6261 /*
6262 * No longer have used bytes in this block group, queue it for
6263 * deletion. We do this after adding the block group to the
6264 * dirty list to avoid races between cleaner kthread and space
6265 * cache writeout.
6266 */
6267 if (!alloc && old_val == 0) {
6268 spin_lock(&info->unused_bgs_lock);
6269 if (list_empty(&cache->bg_list)) {
6270 btrfs_get_block_group(cache);
6271 list_add_tail(&cache->bg_list,
6272 &info->unused_bgs);
6273 }
6274 spin_unlock(&info->unused_bgs_lock);
6275 }
6276
6277 btrfs_put_block_group(cache);
6278 total -= num_bytes;
6279 bytenr += num_bytes;
6280 }
6281 return 0;
6282 }
6283
6284 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
6285 {
6286 struct btrfs_block_group_cache *cache;
6287 u64 bytenr;
6288
6289 spin_lock(&root->fs_info->block_group_cache_lock);
6290 bytenr = root->fs_info->first_logical_byte;
6291 spin_unlock(&root->fs_info->block_group_cache_lock);
6292
6293 if (bytenr < (u64)-1)
6294 return bytenr;
6295
6296 cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
6297 if (!cache)
6298 return 0;
6299
6300 bytenr = cache->key.objectid;
6301 btrfs_put_block_group(cache);
6302
6303 return bytenr;
6304 }
6305
6306 static int pin_down_extent(struct btrfs_root *root,
6307 struct btrfs_block_group_cache *cache,
6308 u64 bytenr, u64 num_bytes, int reserved)
6309 {
6310 spin_lock(&cache->space_info->lock);
6311 spin_lock(&cache->lock);
6312 cache->pinned += num_bytes;
6313 cache->space_info->bytes_pinned += num_bytes;
6314 if (reserved) {
6315 cache->reserved -= num_bytes;
6316 cache->space_info->bytes_reserved -= num_bytes;
6317 }
6318 spin_unlock(&cache->lock);
6319 spin_unlock(&cache->space_info->lock);
6320
6321 trace_btrfs_space_reservation(root->fs_info, "pinned",
6322 cache->space_info->flags, num_bytes, 1);
6323 set_extent_dirty(root->fs_info->pinned_extents, bytenr,
6324 bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
6325 return 0;
6326 }
6327
6328 /*
6329 * this function must be called within transaction
6330 */
6331 int btrfs_pin_extent(struct btrfs_root *root,
6332 u64 bytenr, u64 num_bytes, int reserved)
6333 {
6334 struct btrfs_block_group_cache *cache;
6335
6336 cache = btrfs_lookup_block_group(root->fs_info, bytenr);
6337 BUG_ON(!cache); /* Logic error */
6338
6339 pin_down_extent(root, cache, bytenr, num_bytes, reserved);
6340
6341 btrfs_put_block_group(cache);
6342 return 0;
6343 }
6344
6345 /*
6346 * this function must be called within transaction
6347 */
6348 int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
6349 u64 bytenr, u64 num_bytes)
6350 {
6351 struct btrfs_block_group_cache *cache;
6352 int ret;
6353
6354 cache = btrfs_lookup_block_group(root->fs_info, bytenr);
6355 if (!cache)
6356 return -EINVAL;
6357
6358 /*
6359 * pull in the free space cache (if any) so that our pin
6360 * removes the free space from the cache. We have load_only set
6361 * to one because the slow code to read in the free extents does check
6362 * the pinned extents.
6363 */
6364 cache_block_group(cache, 1);
6365
6366 pin_down_extent(root, cache, bytenr, num_bytes, 0);
6367
6368 /* remove us from the free space cache (if we're there at all) */
6369 ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
6370 btrfs_put_block_group(cache);
6371 return ret;
6372 }
6373
6374 static int __exclude_logged_extent(struct btrfs_root *root, u64 start, u64 num_bytes)
6375 {
6376 int ret;
6377 struct btrfs_block_group_cache *block_group;
6378 struct btrfs_caching_control *caching_ctl;
6379
6380 block_group = btrfs_lookup_block_group(root->fs_info, start);
6381 if (!block_group)
6382 return -EINVAL;
6383
6384 cache_block_group(block_group, 0);
6385 caching_ctl = get_caching_control(block_group);
6386
6387 if (!caching_ctl) {
6388 /* Logic error */
6389 BUG_ON(!block_group_cache_done(block_group));
6390 ret = btrfs_remove_free_space(block_group, start, num_bytes);
6391 } else {
6392 mutex_lock(&caching_ctl->mutex);
6393
6394 if (start >= caching_ctl->progress) {
6395 ret = add_excluded_extent(root, start, num_bytes);
6396 } else if (start + num_bytes <= caching_ctl->progress) {
6397 ret = btrfs_remove_free_space(block_group,
6398 start, num_bytes);
6399 } else {
6400 num_bytes = caching_ctl->progress - start;
6401 ret = btrfs_remove_free_space(block_group,
6402 start, num_bytes);
6403 if (ret)
6404 goto out_lock;
6405
6406 num_bytes = (start + num_bytes) -
6407 caching_ctl->progress;
6408 start = caching_ctl->progress;
6409 ret = add_excluded_extent(root, start, num_bytes);
6410 }
6411 out_lock:
6412 mutex_unlock(&caching_ctl->mutex);
6413 put_caching_control(caching_ctl);
6414 }
6415 btrfs_put_block_group(block_group);
6416 return ret;
6417 }
6418
6419 int btrfs_exclude_logged_extents(struct btrfs_root *log,
6420 struct extent_buffer *eb)
6421 {
6422 struct btrfs_file_extent_item *item;
6423 struct btrfs_key key;
6424 int found_type;
6425 int i;
6426
6427 if (!btrfs_fs_incompat(log->fs_info, MIXED_GROUPS))
6428 return 0;
6429
6430 for (i = 0; i < btrfs_header_nritems(eb); i++) {
6431 btrfs_item_key_to_cpu(eb, &key, i);
6432 if (key.type != BTRFS_EXTENT_DATA_KEY)
6433 continue;
6434 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
6435 found_type = btrfs_file_extent_type(eb, item);
6436 if (found_type == BTRFS_FILE_EXTENT_INLINE)
6437 continue;
6438 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
6439 continue;
6440 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
6441 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
6442 __exclude_logged_extent(log, key.objectid, key.offset);
6443 }
6444
6445 return 0;
6446 }
6447
6448 static void
6449 btrfs_inc_block_group_reservations(struct btrfs_block_group_cache *bg)
6450 {
6451 atomic_inc(&bg->reservations);
6452 }
6453
6454 void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
6455 const u64 start)
6456 {
6457 struct btrfs_block_group_cache *bg;
6458
6459 bg = btrfs_lookup_block_group(fs_info, start);
6460 ASSERT(bg);
6461 if (atomic_dec_and_test(&bg->reservations))
6462 wake_up_atomic_t(&bg->reservations);
6463 btrfs_put_block_group(bg);
6464 }
6465
6466 static int btrfs_wait_bg_reservations_atomic_t(atomic_t *a)
6467 {
6468 schedule();
6469 return 0;
6470 }
6471
6472 void btrfs_wait_block_group_reservations(struct btrfs_block_group_cache *bg)
6473 {
6474 struct btrfs_space_info *space_info = bg->space_info;
6475
6476 ASSERT(bg->ro);
6477
6478 if (!(bg->flags & BTRFS_BLOCK_GROUP_DATA))
6479 return;
6480
6481 /*
6482 * Our block group is read only but before we set it to read only,
6483 * some task might have had allocated an extent from it already, but it
6484 * has not yet created a respective ordered extent (and added it to a
6485 * root's list of ordered extents).
6486 * Therefore wait for any task currently allocating extents, since the
6487 * block group's reservations counter is incremented while a read lock
6488 * on the groups' semaphore is held and decremented after releasing
6489 * the read access on that semaphore and creating the ordered extent.
6490 */
6491 down_write(&space_info->groups_sem);
6492 up_write(&space_info->groups_sem);
6493
6494 wait_on_atomic_t(&bg->reservations,
6495 btrfs_wait_bg_reservations_atomic_t,
6496 TASK_UNINTERRUPTIBLE);
6497 }
6498
6499 /**
6500 * btrfs_update_reserved_bytes - update the block_group and space info counters
6501 * @cache: The cache we are manipulating
6502 * @num_bytes: The number of bytes in question
6503 * @reserve: One of the reservation enums
6504 * @delalloc: The blocks are allocated for the delalloc write
6505 *
6506 * This is called by the allocator when it reserves space, or by somebody who is
6507 * freeing space that was never actually used on disk. For example if you
6508 * reserve some space for a new leaf in transaction A and before transaction A
6509 * commits you free that leaf, you call this with reserve set to 0 in order to
6510 * clear the reservation.
6511 *
6512 * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
6513 * ENOSPC accounting. For data we handle the reservation through clearing the
6514 * delalloc bits in the io_tree. We have to do this since we could end up
6515 * allocating less disk space for the amount of data we have reserved in the
6516 * case of compression.
6517 *
6518 * If this is a reservation and the block group has become read only we cannot
6519 * make the reservation and return -EAGAIN, otherwise this function always
6520 * succeeds.
6521 */
6522 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
6523 u64 num_bytes, int reserve, int delalloc)
6524 {
6525 struct btrfs_space_info *space_info = cache->space_info;
6526 int ret = 0;
6527
6528 spin_lock(&space_info->lock);
6529 spin_lock(&cache->lock);
6530 if (reserve != RESERVE_FREE) {
6531 if (cache->ro) {
6532 ret = -EAGAIN;
6533 } else {
6534 cache->reserved += num_bytes;
6535 space_info->bytes_reserved += num_bytes;
6536 if (reserve == RESERVE_ALLOC) {
6537 trace_btrfs_space_reservation(cache->fs_info,
6538 "space_info", space_info->flags,
6539 num_bytes, 0);
6540 space_info->bytes_may_use -= num_bytes;
6541 }
6542
6543 if (delalloc)
6544 cache->delalloc_bytes += num_bytes;
6545 }
6546 } else {
6547 if (cache->ro)
6548 space_info->bytes_readonly += num_bytes;
6549 cache->reserved -= num_bytes;
6550 space_info->bytes_reserved -= num_bytes;
6551
6552 if (delalloc)
6553 cache->delalloc_bytes -= num_bytes;
6554 }
6555 spin_unlock(&cache->lock);
6556 spin_unlock(&space_info->lock);
6557 return ret;
6558 }
6559
6560 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
6561 struct btrfs_root *root)
6562 {
6563 struct btrfs_fs_info *fs_info = root->fs_info;
6564 struct btrfs_caching_control *next;
6565 struct btrfs_caching_control *caching_ctl;
6566 struct btrfs_block_group_cache *cache;
6567
6568 down_write(&fs_info->commit_root_sem);
6569
6570 list_for_each_entry_safe(caching_ctl, next,
6571 &fs_info->caching_block_groups, list) {
6572 cache = caching_ctl->block_group;
6573 if (block_group_cache_done(cache)) {
6574 cache->last_byte_to_unpin = (u64)-1;
6575 list_del_init(&caching_ctl->list);
6576 put_caching_control(caching_ctl);
6577 } else {
6578 cache->last_byte_to_unpin = caching_ctl->progress;
6579 }
6580 }
6581
6582 if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6583 fs_info->pinned_extents = &fs_info->freed_extents[1];
6584 else
6585 fs_info->pinned_extents = &fs_info->freed_extents[0];
6586
6587 up_write(&fs_info->commit_root_sem);
6588
6589 update_global_block_rsv(fs_info);
6590 }
6591
6592 /*
6593 * Returns the free cluster for the given space info and sets empty_cluster to
6594 * what it should be based on the mount options.
6595 */
6596 static struct btrfs_free_cluster *
6597 fetch_cluster_info(struct btrfs_root *root, struct btrfs_space_info *space_info,
6598 u64 *empty_cluster)
6599 {
6600 struct btrfs_free_cluster *ret = NULL;
6601 bool ssd = btrfs_test_opt(root->fs_info, SSD);
6602
6603 *empty_cluster = 0;
6604 if (btrfs_mixed_space_info(space_info))
6605 return ret;
6606
6607 if (ssd)
6608 *empty_cluster = SZ_2M;
6609 if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
6610 ret = &root->fs_info->meta_alloc_cluster;
6611 if (!ssd)
6612 *empty_cluster = SZ_64K;
6613 } else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) && ssd) {
6614 ret = &root->fs_info->data_alloc_cluster;
6615 }
6616
6617 return ret;
6618 }
6619
6620 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end,
6621 const bool return_free_space)
6622 {
6623 struct btrfs_fs_info *fs_info = root->fs_info;
6624 struct btrfs_block_group_cache *cache = NULL;
6625 struct btrfs_space_info *space_info;
6626 struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
6627 struct btrfs_free_cluster *cluster = NULL;
6628 u64 len;
6629 u64 total_unpinned = 0;
6630 u64 empty_cluster = 0;
6631 bool readonly;
6632
6633 while (start <= end) {
6634 readonly = false;
6635 if (!cache ||
6636 start >= cache->key.objectid + cache->key.offset) {
6637 if (cache)
6638 btrfs_put_block_group(cache);
6639 total_unpinned = 0;
6640 cache = btrfs_lookup_block_group(fs_info, start);
6641 BUG_ON(!cache); /* Logic error */
6642
6643 cluster = fetch_cluster_info(root,
6644 cache->space_info,
6645 &empty_cluster);
6646 empty_cluster <<= 1;
6647 }
6648
6649 len = cache->key.objectid + cache->key.offset - start;
6650 len = min(len, end + 1 - start);
6651
6652 if (start < cache->last_byte_to_unpin) {
6653 len = min(len, cache->last_byte_to_unpin - start);
6654 if (return_free_space)
6655 btrfs_add_free_space(cache, start, len);
6656 }
6657
6658 start += len;
6659 total_unpinned += len;
6660 space_info = cache->space_info;
6661
6662 /*
6663 * If this space cluster has been marked as fragmented and we've
6664 * unpinned enough in this block group to potentially allow a
6665 * cluster to be created inside of it go ahead and clear the
6666 * fragmented check.
6667 */
6668 if (cluster && cluster->fragmented &&
6669 total_unpinned > empty_cluster) {
6670 spin_lock(&cluster->lock);
6671 cluster->fragmented = 0;
6672 spin_unlock(&cluster->lock);
6673 }
6674
6675 spin_lock(&space_info->lock);
6676 spin_lock(&cache->lock);
6677 cache->pinned -= len;
6678 space_info->bytes_pinned -= len;
6679
6680 trace_btrfs_space_reservation(fs_info, "pinned",
6681 space_info->flags, len, 0);
6682 space_info->max_extent_size = 0;
6683 percpu_counter_add(&space_info->total_bytes_pinned, -len);
6684 if (cache->ro) {
6685 space_info->bytes_readonly += len;
6686 readonly = true;
6687 }
6688 spin_unlock(&cache->lock);
6689 if (!readonly && return_free_space &&
6690 global_rsv->space_info == space_info) {
6691 u64 to_add = len;
6692 WARN_ON(!return_free_space);
6693 spin_lock(&global_rsv->lock);
6694 if (!global_rsv->full) {
6695 to_add = min(len, global_rsv->size -
6696 global_rsv->reserved);
6697 global_rsv->reserved += to_add;
6698 space_info->bytes_may_use += to_add;
6699 if (global_rsv->reserved >= global_rsv->size)
6700 global_rsv->full = 1;
6701 trace_btrfs_space_reservation(fs_info,
6702 "space_info",
6703 space_info->flags,
6704 to_add, 1);
6705 len -= to_add;
6706 }
6707 spin_unlock(&global_rsv->lock);
6708 /* Add to any tickets we may have */
6709 if (len)
6710 space_info_add_new_bytes(fs_info, space_info,
6711 len);
6712 }
6713 spin_unlock(&space_info->lock);
6714 }
6715
6716 if (cache)
6717 btrfs_put_block_group(cache);
6718 return 0;
6719 }
6720
6721 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
6722 struct btrfs_root *root)
6723 {
6724 struct btrfs_fs_info *fs_info = root->fs_info;
6725 struct btrfs_block_group_cache *block_group, *tmp;
6726 struct list_head *deleted_bgs;
6727 struct extent_io_tree *unpin;
6728 u64 start;
6729 u64 end;
6730 int ret;
6731
6732 if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6733 unpin = &fs_info->freed_extents[1];
6734 else
6735 unpin = &fs_info->freed_extents[0];
6736
6737 while (!trans->aborted) {
6738 mutex_lock(&fs_info->unused_bg_unpin_mutex);
6739 ret = find_first_extent_bit(unpin, 0, &start, &end,
6740 EXTENT_DIRTY, NULL);
6741 if (ret) {
6742 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6743 break;
6744 }
6745
6746 if (btrfs_test_opt(root->fs_info, DISCARD))
6747 ret = btrfs_discard_extent(root, start,
6748 end + 1 - start, NULL);
6749
6750 clear_extent_dirty(unpin, start, end);
6751 unpin_extent_range(root, start, end, true);
6752 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6753 cond_resched();
6754 }
6755
6756 /*
6757 * Transaction is finished. We don't need the lock anymore. We
6758 * do need to clean up the block groups in case of a transaction
6759 * abort.
6760 */
6761 deleted_bgs = &trans->transaction->deleted_bgs;
6762 list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
6763 u64 trimmed = 0;
6764
6765 ret = -EROFS;
6766 if (!trans->aborted)
6767 ret = btrfs_discard_extent(root,
6768 block_group->key.objectid,
6769 block_group->key.offset,
6770 &trimmed);
6771
6772 list_del_init(&block_group->bg_list);
6773 btrfs_put_block_group_trimming(block_group);
6774 btrfs_put_block_group(block_group);
6775
6776 if (ret) {
6777 const char *errstr = btrfs_decode_error(ret);
6778 btrfs_warn(fs_info,
6779 "Discard failed while removing blockgroup: errno=%d %s\n",
6780 ret, errstr);
6781 }
6782 }
6783
6784 return 0;
6785 }
6786
6787 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, u64 num_bytes,
6788 u64 owner, u64 root_objectid)
6789 {
6790 struct btrfs_space_info *space_info;
6791 u64 flags;
6792
6793 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6794 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
6795 flags = BTRFS_BLOCK_GROUP_SYSTEM;
6796 else
6797 flags = BTRFS_BLOCK_GROUP_METADATA;
6798 } else {
6799 flags = BTRFS_BLOCK_GROUP_DATA;
6800 }
6801
6802 space_info = __find_space_info(fs_info, flags);
6803 BUG_ON(!space_info); /* Logic bug */
6804 percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
6805 }
6806
6807
6808 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
6809 struct btrfs_root *root,
6810 struct btrfs_delayed_ref_node *node, u64 parent,
6811 u64 root_objectid, u64 owner_objectid,
6812 u64 owner_offset, int refs_to_drop,
6813 struct btrfs_delayed_extent_op *extent_op)
6814 {
6815 struct btrfs_key key;
6816 struct btrfs_path *path;
6817 struct btrfs_fs_info *info = root->fs_info;
6818 struct btrfs_root *extent_root = info->extent_root;
6819 struct extent_buffer *leaf;
6820 struct btrfs_extent_item *ei;
6821 struct btrfs_extent_inline_ref *iref;
6822 int ret;
6823 int is_data;
6824 int extent_slot = 0;
6825 int found_extent = 0;
6826 int num_to_del = 1;
6827 u32 item_size;
6828 u64 refs;
6829 u64 bytenr = node->bytenr;
6830 u64 num_bytes = node->num_bytes;
6831 int last_ref = 0;
6832 bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6833 SKINNY_METADATA);
6834
6835 path = btrfs_alloc_path();
6836 if (!path)
6837 return -ENOMEM;
6838
6839 path->reada = READA_FORWARD;
6840 path->leave_spinning = 1;
6841
6842 is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
6843 BUG_ON(!is_data && refs_to_drop != 1);
6844
6845 if (is_data)
6846 skinny_metadata = 0;
6847
6848 ret = lookup_extent_backref(trans, extent_root, path, &iref,
6849 bytenr, num_bytes, parent,
6850 root_objectid, owner_objectid,
6851 owner_offset);
6852 if (ret == 0) {
6853 extent_slot = path->slots[0];
6854 while (extent_slot >= 0) {
6855 btrfs_item_key_to_cpu(path->nodes[0], &key,
6856 extent_slot);
6857 if (key.objectid != bytenr)
6858 break;
6859 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
6860 key.offset == num_bytes) {
6861 found_extent = 1;
6862 break;
6863 }
6864 if (key.type == BTRFS_METADATA_ITEM_KEY &&
6865 key.offset == owner_objectid) {
6866 found_extent = 1;
6867 break;
6868 }
6869 if (path->slots[0] - extent_slot > 5)
6870 break;
6871 extent_slot--;
6872 }
6873 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6874 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
6875 if (found_extent && item_size < sizeof(*ei))
6876 found_extent = 0;
6877 #endif
6878 if (!found_extent) {
6879 BUG_ON(iref);
6880 ret = remove_extent_backref(trans, extent_root, path,
6881 NULL, refs_to_drop,
6882 is_data, &last_ref);
6883 if (ret) {
6884 btrfs_abort_transaction(trans, ret);
6885 goto out;
6886 }
6887 btrfs_release_path(path);
6888 path->leave_spinning = 1;
6889
6890 key.objectid = bytenr;
6891 key.type = BTRFS_EXTENT_ITEM_KEY;
6892 key.offset = num_bytes;
6893
6894 if (!is_data && skinny_metadata) {
6895 key.type = BTRFS_METADATA_ITEM_KEY;
6896 key.offset = owner_objectid;
6897 }
6898
6899 ret = btrfs_search_slot(trans, extent_root,
6900 &key, path, -1, 1);
6901 if (ret > 0 && skinny_metadata && path->slots[0]) {
6902 /*
6903 * Couldn't find our skinny metadata item,
6904 * see if we have ye olde extent item.
6905 */
6906 path->slots[0]--;
6907 btrfs_item_key_to_cpu(path->nodes[0], &key,
6908 path->slots[0]);
6909 if (key.objectid == bytenr &&
6910 key.type == BTRFS_EXTENT_ITEM_KEY &&
6911 key.offset == num_bytes)
6912 ret = 0;
6913 }
6914
6915 if (ret > 0 && skinny_metadata) {
6916 skinny_metadata = false;
6917 key.objectid = bytenr;
6918 key.type = BTRFS_EXTENT_ITEM_KEY;
6919 key.offset = num_bytes;
6920 btrfs_release_path(path);
6921 ret = btrfs_search_slot(trans, extent_root,
6922 &key, path, -1, 1);
6923 }
6924
6925 if (ret) {
6926 btrfs_err(info, "umm, got %d back from search, was looking for %llu",
6927 ret, bytenr);
6928 if (ret > 0)
6929 btrfs_print_leaf(extent_root,
6930 path->nodes[0]);
6931 }
6932 if (ret < 0) {
6933 btrfs_abort_transaction(trans, ret);
6934 goto out;
6935 }
6936 extent_slot = path->slots[0];
6937 }
6938 } else if (WARN_ON(ret == -ENOENT)) {
6939 btrfs_print_leaf(extent_root, path->nodes[0]);
6940 btrfs_err(info,
6941 "unable to find ref byte nr %llu parent %llu root %llu owner %llu offset %llu",
6942 bytenr, parent, root_objectid, owner_objectid,
6943 owner_offset);
6944 btrfs_abort_transaction(trans, ret);
6945 goto out;
6946 } else {
6947 btrfs_abort_transaction(trans, ret);
6948 goto out;
6949 }
6950
6951 leaf = path->nodes[0];
6952 item_size = btrfs_item_size_nr(leaf, extent_slot);
6953 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6954 if (item_size < sizeof(*ei)) {
6955 BUG_ON(found_extent || extent_slot != path->slots[0]);
6956 ret = convert_extent_item_v0(trans, extent_root, path,
6957 owner_objectid, 0);
6958 if (ret < 0) {
6959 btrfs_abort_transaction(trans, ret);
6960 goto out;
6961 }
6962
6963 btrfs_release_path(path);
6964 path->leave_spinning = 1;
6965
6966 key.objectid = bytenr;
6967 key.type = BTRFS_EXTENT_ITEM_KEY;
6968 key.offset = num_bytes;
6969
6970 ret = btrfs_search_slot(trans, extent_root, &key, path,
6971 -1, 1);
6972 if (ret) {
6973 btrfs_err(info, "umm, got %d back from search, was looking for %llu",
6974 ret, bytenr);
6975 btrfs_print_leaf(extent_root, path->nodes[0]);
6976 }
6977 if (ret < 0) {
6978 btrfs_abort_transaction(trans, ret);
6979 goto out;
6980 }
6981
6982 extent_slot = path->slots[0];
6983 leaf = path->nodes[0];
6984 item_size = btrfs_item_size_nr(leaf, extent_slot);
6985 }
6986 #endif
6987 BUG_ON(item_size < sizeof(*ei));
6988 ei = btrfs_item_ptr(leaf, extent_slot,
6989 struct btrfs_extent_item);
6990 if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
6991 key.type == BTRFS_EXTENT_ITEM_KEY) {
6992 struct btrfs_tree_block_info *bi;
6993 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
6994 bi = (struct btrfs_tree_block_info *)(ei + 1);
6995 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
6996 }
6997
6998 refs = btrfs_extent_refs(leaf, ei);
6999 if (refs < refs_to_drop) {
7000 btrfs_err(info, "trying to drop %d refs but we only have %Lu "
7001 "for bytenr %Lu", refs_to_drop, refs, bytenr);
7002 ret = -EINVAL;
7003 btrfs_abort_transaction(trans, ret);
7004 goto out;
7005 }
7006 refs -= refs_to_drop;
7007
7008 if (refs > 0) {
7009 if (extent_op)
7010 __run_delayed_extent_op(extent_op, leaf, ei);
7011 /*
7012 * In the case of inline back ref, reference count will
7013 * be updated by remove_extent_backref
7014 */
7015 if (iref) {
7016 BUG_ON(!found_extent);
7017 } else {
7018 btrfs_set_extent_refs(leaf, ei, refs);
7019 btrfs_mark_buffer_dirty(leaf);
7020 }
7021 if (found_extent) {
7022 ret = remove_extent_backref(trans, extent_root, path,
7023 iref, refs_to_drop,
7024 is_data, &last_ref);
7025 if (ret) {
7026 btrfs_abort_transaction(trans, ret);
7027 goto out;
7028 }
7029 }
7030 add_pinned_bytes(root->fs_info, -num_bytes, owner_objectid,
7031 root_objectid);
7032 } else {
7033 if (found_extent) {
7034 BUG_ON(is_data && refs_to_drop !=
7035 extent_data_ref_count(path, iref));
7036 if (iref) {
7037 BUG_ON(path->slots[0] != extent_slot);
7038 } else {
7039 BUG_ON(path->slots[0] != extent_slot + 1);
7040 path->slots[0] = extent_slot;
7041 num_to_del = 2;
7042 }
7043 }
7044
7045 last_ref = 1;
7046 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
7047 num_to_del);
7048 if (ret) {
7049 btrfs_abort_transaction(trans, ret);
7050 goto out;
7051 }
7052 btrfs_release_path(path);
7053
7054 if (is_data) {
7055 ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
7056 if (ret) {
7057 btrfs_abort_transaction(trans, ret);
7058 goto out;
7059 }
7060 }
7061
7062 ret = add_to_free_space_tree(trans, root->fs_info, bytenr,
7063 num_bytes);
7064 if (ret) {
7065 btrfs_abort_transaction(trans, ret);
7066 goto out;
7067 }
7068
7069 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
7070 if (ret) {
7071 btrfs_abort_transaction(trans, ret);
7072 goto out;
7073 }
7074 }
7075 btrfs_release_path(path);
7076
7077 out:
7078 btrfs_free_path(path);
7079 return ret;
7080 }
7081
7082 /*
7083 * when we free an block, it is possible (and likely) that we free the last
7084 * delayed ref for that extent as well. This searches the delayed ref tree for
7085 * a given extent, and if there are no other delayed refs to be processed, it
7086 * removes it from the tree.
7087 */
7088 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
7089 struct btrfs_root *root, u64 bytenr)
7090 {
7091 struct btrfs_delayed_ref_head *head;
7092 struct btrfs_delayed_ref_root *delayed_refs;
7093 int ret = 0;
7094
7095 delayed_refs = &trans->transaction->delayed_refs;
7096 spin_lock(&delayed_refs->lock);
7097 head = btrfs_find_delayed_ref_head(trans, bytenr);
7098 if (!head)
7099 goto out_delayed_unlock;
7100
7101 spin_lock(&head->lock);
7102 if (!list_empty(&head->ref_list))
7103 goto out;
7104
7105 if (head->extent_op) {
7106 if (!head->must_insert_reserved)
7107 goto out;
7108 btrfs_free_delayed_extent_op(head->extent_op);
7109 head->extent_op = NULL;
7110 }
7111
7112 /*
7113 * waiting for the lock here would deadlock. If someone else has it
7114 * locked they are already in the process of dropping it anyway
7115 */
7116 if (!mutex_trylock(&head->mutex))
7117 goto out;
7118
7119 /*
7120 * at this point we have a head with no other entries. Go
7121 * ahead and process it.
7122 */
7123 head->node.in_tree = 0;
7124 rb_erase(&head->href_node, &delayed_refs->href_root);
7125
7126 atomic_dec(&delayed_refs->num_entries);
7127
7128 /*
7129 * we don't take a ref on the node because we're removing it from the
7130 * tree, so we just steal the ref the tree was holding.
7131 */
7132 delayed_refs->num_heads--;
7133 if (head->processing == 0)
7134 delayed_refs->num_heads_ready--;
7135 head->processing = 0;
7136 spin_unlock(&head->lock);
7137 spin_unlock(&delayed_refs->lock);
7138
7139 BUG_ON(head->extent_op);
7140 if (head->must_insert_reserved)
7141 ret = 1;
7142
7143 mutex_unlock(&head->mutex);
7144 btrfs_put_delayed_ref(&head->node);
7145 return ret;
7146 out:
7147 spin_unlock(&head->lock);
7148
7149 out_delayed_unlock:
7150 spin_unlock(&delayed_refs->lock);
7151 return 0;
7152 }
7153
7154 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
7155 struct btrfs_root *root,
7156 struct extent_buffer *buf,
7157 u64 parent, int last_ref)
7158 {
7159 int pin = 1;
7160 int ret;
7161
7162 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7163 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
7164 buf->start, buf->len,
7165 parent, root->root_key.objectid,
7166 btrfs_header_level(buf),
7167 BTRFS_DROP_DELAYED_REF, NULL);
7168 BUG_ON(ret); /* -ENOMEM */
7169 }
7170
7171 if (!last_ref)
7172 return;
7173
7174 if (btrfs_header_generation(buf) == trans->transid) {
7175 struct btrfs_block_group_cache *cache;
7176
7177 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7178 ret = check_ref_cleanup(trans, root, buf->start);
7179 if (!ret)
7180 goto out;
7181 }
7182
7183 cache = btrfs_lookup_block_group(root->fs_info, buf->start);
7184
7185 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
7186 pin_down_extent(root, cache, buf->start, buf->len, 1);
7187 btrfs_put_block_group(cache);
7188 goto out;
7189 }
7190
7191 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
7192
7193 btrfs_add_free_space(cache, buf->start, buf->len);
7194 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE, 0);
7195 btrfs_put_block_group(cache);
7196 trace_btrfs_reserved_extent_free(root, buf->start, buf->len);
7197 pin = 0;
7198 }
7199 out:
7200 if (pin)
7201 add_pinned_bytes(root->fs_info, buf->len,
7202 btrfs_header_level(buf),
7203 root->root_key.objectid);
7204
7205 /*
7206 * Deleting the buffer, clear the corrupt flag since it doesn't matter
7207 * anymore.
7208 */
7209 clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
7210 }
7211
7212 /* Can return -ENOMEM */
7213 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
7214 u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
7215 u64 owner, u64 offset)
7216 {
7217 int ret;
7218 struct btrfs_fs_info *fs_info = root->fs_info;
7219
7220 if (btrfs_is_testing(fs_info))
7221 return 0;
7222
7223 add_pinned_bytes(root->fs_info, num_bytes, owner, root_objectid);
7224
7225 /*
7226 * tree log blocks never actually go into the extent allocation
7227 * tree, just update pinning info and exit early.
7228 */
7229 if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
7230 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
7231 /* unlocks the pinned mutex */
7232 btrfs_pin_extent(root, bytenr, num_bytes, 1);
7233 ret = 0;
7234 } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
7235 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
7236 num_bytes,
7237 parent, root_objectid, (int)owner,
7238 BTRFS_DROP_DELAYED_REF, NULL);
7239 } else {
7240 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
7241 num_bytes,
7242 parent, root_objectid, owner,
7243 offset, 0,
7244 BTRFS_DROP_DELAYED_REF, NULL);
7245 }
7246 return ret;
7247 }
7248
7249 /*
7250 * when we wait for progress in the block group caching, its because
7251 * our allocation attempt failed at least once. So, we must sleep
7252 * and let some progress happen before we try again.
7253 *
7254 * This function will sleep at least once waiting for new free space to
7255 * show up, and then it will check the block group free space numbers
7256 * for our min num_bytes. Another option is to have it go ahead
7257 * and look in the rbtree for a free extent of a given size, but this
7258 * is a good start.
7259 *
7260 * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
7261 * any of the information in this block group.
7262 */
7263 static noinline void
7264 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
7265 u64 num_bytes)
7266 {
7267 struct btrfs_caching_control *caching_ctl;
7268
7269 caching_ctl = get_caching_control(cache);
7270 if (!caching_ctl)
7271 return;
7272
7273 wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
7274 (cache->free_space_ctl->free_space >= num_bytes));
7275
7276 put_caching_control(caching_ctl);
7277 }
7278
7279 static noinline int
7280 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
7281 {
7282 struct btrfs_caching_control *caching_ctl;
7283 int ret = 0;
7284
7285 caching_ctl = get_caching_control(cache);
7286 if (!caching_ctl)
7287 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
7288
7289 wait_event(caching_ctl->wait, block_group_cache_done(cache));
7290 if (cache->cached == BTRFS_CACHE_ERROR)
7291 ret = -EIO;
7292 put_caching_control(caching_ctl);
7293 return ret;
7294 }
7295
7296 int __get_raid_index(u64 flags)
7297 {
7298 if (flags & BTRFS_BLOCK_GROUP_RAID10)
7299 return BTRFS_RAID_RAID10;
7300 else if (flags & BTRFS_BLOCK_GROUP_RAID1)
7301 return BTRFS_RAID_RAID1;
7302 else if (flags & BTRFS_BLOCK_GROUP_DUP)
7303 return BTRFS_RAID_DUP;
7304 else if (flags & BTRFS_BLOCK_GROUP_RAID0)
7305 return BTRFS_RAID_RAID0;
7306 else if (flags & BTRFS_BLOCK_GROUP_RAID5)
7307 return BTRFS_RAID_RAID5;
7308 else if (flags & BTRFS_BLOCK_GROUP_RAID6)
7309 return BTRFS_RAID_RAID6;
7310
7311 return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
7312 }
7313
7314 int get_block_group_index(struct btrfs_block_group_cache *cache)
7315 {
7316 return __get_raid_index(cache->flags);
7317 }
7318
7319 static const char *btrfs_raid_type_names[BTRFS_NR_RAID_TYPES] = {
7320 [BTRFS_RAID_RAID10] = "raid10",
7321 [BTRFS_RAID_RAID1] = "raid1",
7322 [BTRFS_RAID_DUP] = "dup",
7323 [BTRFS_RAID_RAID0] = "raid0",
7324 [BTRFS_RAID_SINGLE] = "single",
7325 [BTRFS_RAID_RAID5] = "raid5",
7326 [BTRFS_RAID_RAID6] = "raid6",
7327 };
7328
7329 static const char *get_raid_name(enum btrfs_raid_types type)
7330 {
7331 if (type >= BTRFS_NR_RAID_TYPES)
7332 return NULL;
7333
7334 return btrfs_raid_type_names[type];
7335 }
7336
7337 enum btrfs_loop_type {
7338 LOOP_CACHING_NOWAIT = 0,
7339 LOOP_CACHING_WAIT = 1,
7340 LOOP_ALLOC_CHUNK = 2,
7341 LOOP_NO_EMPTY_SIZE = 3,
7342 };
7343
7344 static inline void
7345 btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
7346 int delalloc)
7347 {
7348 if (delalloc)
7349 down_read(&cache->data_rwsem);
7350 }
7351
7352 static inline void
7353 btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
7354 int delalloc)
7355 {
7356 btrfs_get_block_group(cache);
7357 if (delalloc)
7358 down_read(&cache->data_rwsem);
7359 }
7360
7361 static struct btrfs_block_group_cache *
7362 btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
7363 struct btrfs_free_cluster *cluster,
7364 int delalloc)
7365 {
7366 struct btrfs_block_group_cache *used_bg = NULL;
7367
7368 spin_lock(&cluster->refill_lock);
7369 while (1) {
7370 used_bg = cluster->block_group;
7371 if (!used_bg)
7372 return NULL;
7373
7374 if (used_bg == block_group)
7375 return used_bg;
7376
7377 btrfs_get_block_group(used_bg);
7378
7379 if (!delalloc)
7380 return used_bg;
7381
7382 if (down_read_trylock(&used_bg->data_rwsem))
7383 return used_bg;
7384
7385 spin_unlock(&cluster->refill_lock);
7386
7387 down_read(&used_bg->data_rwsem);
7388
7389 spin_lock(&cluster->refill_lock);
7390 if (used_bg == cluster->block_group)
7391 return used_bg;
7392
7393 up_read(&used_bg->data_rwsem);
7394 btrfs_put_block_group(used_bg);
7395 }
7396 }
7397
7398 static inline void
7399 btrfs_release_block_group(struct btrfs_block_group_cache *cache,
7400 int delalloc)
7401 {
7402 if (delalloc)
7403 up_read(&cache->data_rwsem);
7404 btrfs_put_block_group(cache);
7405 }
7406
7407 /*
7408 * walks the btree of allocated extents and find a hole of a given size.
7409 * The key ins is changed to record the hole:
7410 * ins->objectid == start position
7411 * ins->flags = BTRFS_EXTENT_ITEM_KEY
7412 * ins->offset == the size of the hole.
7413 * Any available blocks before search_start are skipped.
7414 *
7415 * If there is no suitable free space, we will record the max size of
7416 * the free space extent currently.
7417 */
7418 static noinline int find_free_extent(struct btrfs_root *orig_root,
7419 u64 num_bytes, u64 empty_size,
7420 u64 hint_byte, struct btrfs_key *ins,
7421 u64 flags, int delalloc)
7422 {
7423 int ret = 0;
7424 struct btrfs_root *root = orig_root->fs_info->extent_root;
7425 struct btrfs_free_cluster *last_ptr = NULL;
7426 struct btrfs_block_group_cache *block_group = NULL;
7427 u64 search_start = 0;
7428 u64 max_extent_size = 0;
7429 u64 empty_cluster = 0;
7430 struct btrfs_space_info *space_info;
7431 int loop = 0;
7432 int index = __get_raid_index(flags);
7433 int alloc_type = (flags & BTRFS_BLOCK_GROUP_DATA) ?
7434 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
7435 bool failed_cluster_refill = false;
7436 bool failed_alloc = false;
7437 bool use_cluster = true;
7438 bool have_caching_bg = false;
7439 bool orig_have_caching_bg = false;
7440 bool full_search = false;
7441
7442 WARN_ON(num_bytes < root->sectorsize);
7443 ins->type = BTRFS_EXTENT_ITEM_KEY;
7444 ins->objectid = 0;
7445 ins->offset = 0;
7446
7447 trace_find_free_extent(orig_root, num_bytes, empty_size, flags);
7448
7449 space_info = __find_space_info(root->fs_info, flags);
7450 if (!space_info) {
7451 btrfs_err(root->fs_info, "No space info for %llu", flags);
7452 return -ENOSPC;
7453 }
7454
7455 /*
7456 * If our free space is heavily fragmented we may not be able to make
7457 * big contiguous allocations, so instead of doing the expensive search
7458 * for free space, simply return ENOSPC with our max_extent_size so we
7459 * can go ahead and search for a more manageable chunk.
7460 *
7461 * If our max_extent_size is large enough for our allocation simply
7462 * disable clustering since we will likely not be able to find enough
7463 * space to create a cluster and induce latency trying.
7464 */
7465 if (unlikely(space_info->max_extent_size)) {
7466 spin_lock(&space_info->lock);
7467 if (space_info->max_extent_size &&
7468 num_bytes > space_info->max_extent_size) {
7469 ins->offset = space_info->max_extent_size;
7470 spin_unlock(&space_info->lock);
7471 return -ENOSPC;
7472 } else if (space_info->max_extent_size) {
7473 use_cluster = false;
7474 }
7475 spin_unlock(&space_info->lock);
7476 }
7477
7478 last_ptr = fetch_cluster_info(orig_root, space_info, &empty_cluster);
7479 if (last_ptr) {
7480 spin_lock(&last_ptr->lock);
7481 if (last_ptr->block_group)
7482 hint_byte = last_ptr->window_start;
7483 if (last_ptr->fragmented) {
7484 /*
7485 * We still set window_start so we can keep track of the
7486 * last place we found an allocation to try and save
7487 * some time.
7488 */
7489 hint_byte = last_ptr->window_start;
7490 use_cluster = false;
7491 }
7492 spin_unlock(&last_ptr->lock);
7493 }
7494
7495 search_start = max(search_start, first_logical_byte(root, 0));
7496 search_start = max(search_start, hint_byte);
7497 if (search_start == hint_byte) {
7498 block_group = btrfs_lookup_block_group(root->fs_info,
7499 search_start);
7500 /*
7501 * we don't want to use the block group if it doesn't match our
7502 * allocation bits, or if its not cached.
7503 *
7504 * However if we are re-searching with an ideal block group
7505 * picked out then we don't care that the block group is cached.
7506 */
7507 if (block_group && block_group_bits(block_group, flags) &&
7508 block_group->cached != BTRFS_CACHE_NO) {
7509 down_read(&space_info->groups_sem);
7510 if (list_empty(&block_group->list) ||
7511 block_group->ro) {
7512 /*
7513 * someone is removing this block group,
7514 * we can't jump into the have_block_group
7515 * target because our list pointers are not
7516 * valid
7517 */
7518 btrfs_put_block_group(block_group);
7519 up_read(&space_info->groups_sem);
7520 } else {
7521 index = get_block_group_index(block_group);
7522 btrfs_lock_block_group(block_group, delalloc);
7523 goto have_block_group;
7524 }
7525 } else if (block_group) {
7526 btrfs_put_block_group(block_group);
7527 }
7528 }
7529 search:
7530 have_caching_bg = false;
7531 if (index == 0 || index == __get_raid_index(flags))
7532 full_search = true;
7533 down_read(&space_info->groups_sem);
7534 list_for_each_entry(block_group, &space_info->block_groups[index],
7535 list) {
7536 u64 offset;
7537 int cached;
7538
7539 btrfs_grab_block_group(block_group, delalloc);
7540 search_start = block_group->key.objectid;
7541
7542 /*
7543 * this can happen if we end up cycling through all the
7544 * raid types, but we want to make sure we only allocate
7545 * for the proper type.
7546 */
7547 if (!block_group_bits(block_group, flags)) {
7548 u64 extra = BTRFS_BLOCK_GROUP_DUP |
7549 BTRFS_BLOCK_GROUP_RAID1 |
7550 BTRFS_BLOCK_GROUP_RAID5 |
7551 BTRFS_BLOCK_GROUP_RAID6 |
7552 BTRFS_BLOCK_GROUP_RAID10;
7553
7554 /*
7555 * if they asked for extra copies and this block group
7556 * doesn't provide them, bail. This does allow us to
7557 * fill raid0 from raid1.
7558 */
7559 if ((flags & extra) && !(block_group->flags & extra))
7560 goto loop;
7561 }
7562
7563 have_block_group:
7564 cached = block_group_cache_done(block_group);
7565 if (unlikely(!cached)) {
7566 have_caching_bg = true;
7567 ret = cache_block_group(block_group, 0);
7568 BUG_ON(ret < 0);
7569 ret = 0;
7570 }
7571
7572 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
7573 goto loop;
7574 if (unlikely(block_group->ro))
7575 goto loop;
7576
7577 /*
7578 * Ok we want to try and use the cluster allocator, so
7579 * lets look there
7580 */
7581 if (last_ptr && use_cluster) {
7582 struct btrfs_block_group_cache *used_block_group;
7583 unsigned long aligned_cluster;
7584 /*
7585 * the refill lock keeps out other
7586 * people trying to start a new cluster
7587 */
7588 used_block_group = btrfs_lock_cluster(block_group,
7589 last_ptr,
7590 delalloc);
7591 if (!used_block_group)
7592 goto refill_cluster;
7593
7594 if (used_block_group != block_group &&
7595 (used_block_group->ro ||
7596 !block_group_bits(used_block_group, flags)))
7597 goto release_cluster;
7598
7599 offset = btrfs_alloc_from_cluster(used_block_group,
7600 last_ptr,
7601 num_bytes,
7602 used_block_group->key.objectid,
7603 &max_extent_size);
7604 if (offset) {
7605 /* we have a block, we're done */
7606 spin_unlock(&last_ptr->refill_lock);
7607 trace_btrfs_reserve_extent_cluster(root,
7608 used_block_group,
7609 search_start, num_bytes);
7610 if (used_block_group != block_group) {
7611 btrfs_release_block_group(block_group,
7612 delalloc);
7613 block_group = used_block_group;
7614 }
7615 goto checks;
7616 }
7617
7618 WARN_ON(last_ptr->block_group != used_block_group);
7619 release_cluster:
7620 /* If we are on LOOP_NO_EMPTY_SIZE, we can't
7621 * set up a new clusters, so lets just skip it
7622 * and let the allocator find whatever block
7623 * it can find. If we reach this point, we
7624 * will have tried the cluster allocator
7625 * plenty of times and not have found
7626 * anything, so we are likely way too
7627 * fragmented for the clustering stuff to find
7628 * anything.
7629 *
7630 * However, if the cluster is taken from the
7631 * current block group, release the cluster
7632 * first, so that we stand a better chance of
7633 * succeeding in the unclustered
7634 * allocation. */
7635 if (loop >= LOOP_NO_EMPTY_SIZE &&
7636 used_block_group != block_group) {
7637 spin_unlock(&last_ptr->refill_lock);
7638 btrfs_release_block_group(used_block_group,
7639 delalloc);
7640 goto unclustered_alloc;
7641 }
7642
7643 /*
7644 * this cluster didn't work out, free it and
7645 * start over
7646 */
7647 btrfs_return_cluster_to_free_space(NULL, last_ptr);
7648
7649 if (used_block_group != block_group)
7650 btrfs_release_block_group(used_block_group,
7651 delalloc);
7652 refill_cluster:
7653 if (loop >= LOOP_NO_EMPTY_SIZE) {
7654 spin_unlock(&last_ptr->refill_lock);
7655 goto unclustered_alloc;
7656 }
7657
7658 aligned_cluster = max_t(unsigned long,
7659 empty_cluster + empty_size,
7660 block_group->full_stripe_len);
7661
7662 /* allocate a cluster in this block group */
7663 ret = btrfs_find_space_cluster(root, block_group,
7664 last_ptr, search_start,
7665 num_bytes,
7666 aligned_cluster);
7667 if (ret == 0) {
7668 /*
7669 * now pull our allocation out of this
7670 * cluster
7671 */
7672 offset = btrfs_alloc_from_cluster(block_group,
7673 last_ptr,
7674 num_bytes,
7675 search_start,
7676 &max_extent_size);
7677 if (offset) {
7678 /* we found one, proceed */
7679 spin_unlock(&last_ptr->refill_lock);
7680 trace_btrfs_reserve_extent_cluster(root,
7681 block_group, search_start,
7682 num_bytes);
7683 goto checks;
7684 }
7685 } else if (!cached && loop > LOOP_CACHING_NOWAIT
7686 && !failed_cluster_refill) {
7687 spin_unlock(&last_ptr->refill_lock);
7688
7689 failed_cluster_refill = true;
7690 wait_block_group_cache_progress(block_group,
7691 num_bytes + empty_cluster + empty_size);
7692 goto have_block_group;
7693 }
7694
7695 /*
7696 * at this point we either didn't find a cluster
7697 * or we weren't able to allocate a block from our
7698 * cluster. Free the cluster we've been trying
7699 * to use, and go to the next block group
7700 */
7701 btrfs_return_cluster_to_free_space(NULL, last_ptr);
7702 spin_unlock(&last_ptr->refill_lock);
7703 goto loop;
7704 }
7705
7706 unclustered_alloc:
7707 /*
7708 * We are doing an unclustered alloc, set the fragmented flag so
7709 * we don't bother trying to setup a cluster again until we get
7710 * more space.
7711 */
7712 if (unlikely(last_ptr)) {
7713 spin_lock(&last_ptr->lock);
7714 last_ptr->fragmented = 1;
7715 spin_unlock(&last_ptr->lock);
7716 }
7717 spin_lock(&block_group->free_space_ctl->tree_lock);
7718 if (cached &&
7719 block_group->free_space_ctl->free_space <
7720 num_bytes + empty_cluster + empty_size) {
7721 if (block_group->free_space_ctl->free_space >
7722 max_extent_size)
7723 max_extent_size =
7724 block_group->free_space_ctl->free_space;
7725 spin_unlock(&block_group->free_space_ctl->tree_lock);
7726 goto loop;
7727 }
7728 spin_unlock(&block_group->free_space_ctl->tree_lock);
7729
7730 offset = btrfs_find_space_for_alloc(block_group, search_start,
7731 num_bytes, empty_size,
7732 &max_extent_size);
7733 /*
7734 * If we didn't find a chunk, and we haven't failed on this
7735 * block group before, and this block group is in the middle of
7736 * caching and we are ok with waiting, then go ahead and wait
7737 * for progress to be made, and set failed_alloc to true.
7738 *
7739 * If failed_alloc is true then we've already waited on this
7740 * block group once and should move on to the next block group.
7741 */
7742 if (!offset && !failed_alloc && !cached &&
7743 loop > LOOP_CACHING_NOWAIT) {
7744 wait_block_group_cache_progress(block_group,
7745 num_bytes + empty_size);
7746 failed_alloc = true;
7747 goto have_block_group;
7748 } else if (!offset) {
7749 goto loop;
7750 }
7751 checks:
7752 search_start = ALIGN(offset, root->stripesize);
7753
7754 /* move on to the next group */
7755 if (search_start + num_bytes >
7756 block_group->key.objectid + block_group->key.offset) {
7757 btrfs_add_free_space(block_group, offset, num_bytes);
7758 goto loop;
7759 }
7760
7761 if (offset < search_start)
7762 btrfs_add_free_space(block_group, offset,
7763 search_start - offset);
7764 BUG_ON(offset > search_start);
7765
7766 ret = btrfs_update_reserved_bytes(block_group, num_bytes,
7767 alloc_type, delalloc);
7768 if (ret == -EAGAIN) {
7769 btrfs_add_free_space(block_group, offset, num_bytes);
7770 goto loop;
7771 }
7772 btrfs_inc_block_group_reservations(block_group);
7773
7774 /* we are all good, lets return */
7775 ins->objectid = search_start;
7776 ins->offset = num_bytes;
7777
7778 trace_btrfs_reserve_extent(orig_root, block_group,
7779 search_start, num_bytes);
7780 btrfs_release_block_group(block_group, delalloc);
7781 break;
7782 loop:
7783 failed_cluster_refill = false;
7784 failed_alloc = false;
7785 BUG_ON(index != get_block_group_index(block_group));
7786 btrfs_release_block_group(block_group, delalloc);
7787 }
7788 up_read(&space_info->groups_sem);
7789
7790 if ((loop == LOOP_CACHING_NOWAIT) && have_caching_bg
7791 && !orig_have_caching_bg)
7792 orig_have_caching_bg = true;
7793
7794 if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
7795 goto search;
7796
7797 if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
7798 goto search;
7799
7800 /*
7801 * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
7802 * caching kthreads as we move along
7803 * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
7804 * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
7805 * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
7806 * again
7807 */
7808 if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
7809 index = 0;
7810 if (loop == LOOP_CACHING_NOWAIT) {
7811 /*
7812 * We want to skip the LOOP_CACHING_WAIT step if we
7813 * don't have any uncached bgs and we've already done a
7814 * full search through.
7815 */
7816 if (orig_have_caching_bg || !full_search)
7817 loop = LOOP_CACHING_WAIT;
7818 else
7819 loop = LOOP_ALLOC_CHUNK;
7820 } else {
7821 loop++;
7822 }
7823
7824 if (loop == LOOP_ALLOC_CHUNK) {
7825 struct btrfs_trans_handle *trans;
7826 int exist = 0;
7827
7828 trans = current->journal_info;
7829 if (trans)
7830 exist = 1;
7831 else
7832 trans = btrfs_join_transaction(root);
7833
7834 if (IS_ERR(trans)) {
7835 ret = PTR_ERR(trans);
7836 goto out;
7837 }
7838
7839 ret = do_chunk_alloc(trans, root, flags,
7840 CHUNK_ALLOC_FORCE);
7841
7842 /*
7843 * If we can't allocate a new chunk we've already looped
7844 * through at least once, move on to the NO_EMPTY_SIZE
7845 * case.
7846 */
7847 if (ret == -ENOSPC)
7848 loop = LOOP_NO_EMPTY_SIZE;
7849
7850 /*
7851 * Do not bail out on ENOSPC since we
7852 * can do more things.
7853 */
7854 if (ret < 0 && ret != -ENOSPC)
7855 btrfs_abort_transaction(trans, ret);
7856 else
7857 ret = 0;
7858 if (!exist)
7859 btrfs_end_transaction(trans, root);
7860 if (ret)
7861 goto out;
7862 }
7863
7864 if (loop == LOOP_NO_EMPTY_SIZE) {
7865 /*
7866 * Don't loop again if we already have no empty_size and
7867 * no empty_cluster.
7868 */
7869 if (empty_size == 0 &&
7870 empty_cluster == 0) {
7871 ret = -ENOSPC;
7872 goto out;
7873 }
7874 empty_size = 0;
7875 empty_cluster = 0;
7876 }
7877
7878 goto search;
7879 } else if (!ins->objectid) {
7880 ret = -ENOSPC;
7881 } else if (ins->objectid) {
7882 if (!use_cluster && last_ptr) {
7883 spin_lock(&last_ptr->lock);
7884 last_ptr->window_start = ins->objectid;
7885 spin_unlock(&last_ptr->lock);
7886 }
7887 ret = 0;
7888 }
7889 out:
7890 if (ret == -ENOSPC) {
7891 spin_lock(&space_info->lock);
7892 space_info->max_extent_size = max_extent_size;
7893 spin_unlock(&space_info->lock);
7894 ins->offset = max_extent_size;
7895 }
7896 return ret;
7897 }
7898
7899 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
7900 int dump_block_groups)
7901 {
7902 struct btrfs_block_group_cache *cache;
7903 int index = 0;
7904
7905 spin_lock(&info->lock);
7906 printk(KERN_INFO "BTRFS: space_info %llu has %llu free, is %sfull\n",
7907 info->flags,
7908 info->total_bytes - info->bytes_used - info->bytes_pinned -
7909 info->bytes_reserved - info->bytes_readonly -
7910 info->bytes_may_use, (info->full) ? "" : "not ");
7911 printk(KERN_INFO "BTRFS: space_info total=%llu, used=%llu, pinned=%llu, "
7912 "reserved=%llu, may_use=%llu, readonly=%llu\n",
7913 info->total_bytes, info->bytes_used, info->bytes_pinned,
7914 info->bytes_reserved, info->bytes_may_use,
7915 info->bytes_readonly);
7916 spin_unlock(&info->lock);
7917
7918 if (!dump_block_groups)
7919 return;
7920
7921 down_read(&info->groups_sem);
7922 again:
7923 list_for_each_entry(cache, &info->block_groups[index], list) {
7924 spin_lock(&cache->lock);
7925 printk(KERN_INFO "BTRFS: "
7926 "block group %llu has %llu bytes, "
7927 "%llu used %llu pinned %llu reserved %s\n",
7928 cache->key.objectid, cache->key.offset,
7929 btrfs_block_group_used(&cache->item), cache->pinned,
7930 cache->reserved, cache->ro ? "[readonly]" : "");
7931 btrfs_dump_free_space(cache, bytes);
7932 spin_unlock(&cache->lock);
7933 }
7934 if (++index < BTRFS_NR_RAID_TYPES)
7935 goto again;
7936 up_read(&info->groups_sem);
7937 }
7938
7939 int btrfs_reserve_extent(struct btrfs_root *root,
7940 u64 num_bytes, u64 min_alloc_size,
7941 u64 empty_size, u64 hint_byte,
7942 struct btrfs_key *ins, int is_data, int delalloc)
7943 {
7944 bool final_tried = num_bytes == min_alloc_size;
7945 u64 flags;
7946 int ret;
7947
7948 flags = btrfs_get_alloc_profile(root, is_data);
7949 again:
7950 WARN_ON(num_bytes < root->sectorsize);
7951 ret = find_free_extent(root, num_bytes, empty_size, hint_byte, ins,
7952 flags, delalloc);
7953 if (!ret && !is_data) {
7954 btrfs_dec_block_group_reservations(root->fs_info,
7955 ins->objectid);
7956 } else if (ret == -ENOSPC) {
7957 if (!final_tried && ins->offset) {
7958 num_bytes = min(num_bytes >> 1, ins->offset);
7959 num_bytes = round_down(num_bytes, root->sectorsize);
7960 num_bytes = max(num_bytes, min_alloc_size);
7961 if (num_bytes == min_alloc_size)
7962 final_tried = true;
7963 goto again;
7964 } else if (btrfs_test_opt(root->fs_info, ENOSPC_DEBUG)) {
7965 struct btrfs_space_info *sinfo;
7966
7967 sinfo = __find_space_info(root->fs_info, flags);
7968 btrfs_err(root->fs_info, "allocation failed flags %llu, wanted %llu",
7969 flags, num_bytes);
7970 if (sinfo)
7971 dump_space_info(sinfo, num_bytes, 1);
7972 }
7973 }
7974
7975 return ret;
7976 }
7977
7978 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
7979 u64 start, u64 len,
7980 int pin, int delalloc)
7981 {
7982 struct btrfs_block_group_cache *cache;
7983 int ret = 0;
7984
7985 cache = btrfs_lookup_block_group(root->fs_info, start);
7986 if (!cache) {
7987 btrfs_err(root->fs_info, "Unable to find block group for %llu",
7988 start);
7989 return -ENOSPC;
7990 }
7991
7992 if (pin)
7993 pin_down_extent(root, cache, start, len, 1);
7994 else {
7995 if (btrfs_test_opt(root->fs_info, DISCARD))
7996 ret = btrfs_discard_extent(root, start, len, NULL);
7997 btrfs_add_free_space(cache, start, len);
7998 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE, delalloc);
7999 trace_btrfs_reserved_extent_free(root, start, len);
8000 }
8001
8002 btrfs_put_block_group(cache);
8003 return ret;
8004 }
8005
8006 int btrfs_free_reserved_extent(struct btrfs_root *root,
8007 u64 start, u64 len, int delalloc)
8008 {
8009 return __btrfs_free_reserved_extent(root, start, len, 0, delalloc);
8010 }
8011
8012 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
8013 u64 start, u64 len)
8014 {
8015 return __btrfs_free_reserved_extent(root, start, len, 1, 0);
8016 }
8017
8018 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8019 struct btrfs_root *root,
8020 u64 parent, u64 root_objectid,
8021 u64 flags, u64 owner, u64 offset,
8022 struct btrfs_key *ins, int ref_mod)
8023 {
8024 int ret;
8025 struct btrfs_fs_info *fs_info = root->fs_info;
8026 struct btrfs_extent_item *extent_item;
8027 struct btrfs_extent_inline_ref *iref;
8028 struct btrfs_path *path;
8029 struct extent_buffer *leaf;
8030 int type;
8031 u32 size;
8032
8033 if (parent > 0)
8034 type = BTRFS_SHARED_DATA_REF_KEY;
8035 else
8036 type = BTRFS_EXTENT_DATA_REF_KEY;
8037
8038 size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
8039
8040 path = btrfs_alloc_path();
8041 if (!path)
8042 return -ENOMEM;
8043
8044 path->leave_spinning = 1;
8045 ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
8046 ins, size);
8047 if (ret) {
8048 btrfs_free_path(path);
8049 return ret;
8050 }
8051
8052 leaf = path->nodes[0];
8053 extent_item = btrfs_item_ptr(leaf, path->slots[0],
8054 struct btrfs_extent_item);
8055 btrfs_set_extent_refs(leaf, extent_item, ref_mod);
8056 btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8057 btrfs_set_extent_flags(leaf, extent_item,
8058 flags | BTRFS_EXTENT_FLAG_DATA);
8059
8060 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8061 btrfs_set_extent_inline_ref_type(leaf, iref, type);
8062 if (parent > 0) {
8063 struct btrfs_shared_data_ref *ref;
8064 ref = (struct btrfs_shared_data_ref *)(iref + 1);
8065 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
8066 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
8067 } else {
8068 struct btrfs_extent_data_ref *ref;
8069 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
8070 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
8071 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
8072 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
8073 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
8074 }
8075
8076 btrfs_mark_buffer_dirty(path->nodes[0]);
8077 btrfs_free_path(path);
8078
8079 ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
8080 ins->offset);
8081 if (ret)
8082 return ret;
8083
8084 ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
8085 if (ret) { /* -ENOENT, logic error */
8086 btrfs_err(fs_info, "update block group failed for %llu %llu",
8087 ins->objectid, ins->offset);
8088 BUG();
8089 }
8090 trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
8091 return ret;
8092 }
8093
8094 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
8095 struct btrfs_root *root,
8096 u64 parent, u64 root_objectid,
8097 u64 flags, struct btrfs_disk_key *key,
8098 int level, struct btrfs_key *ins)
8099 {
8100 int ret;
8101 struct btrfs_fs_info *fs_info = root->fs_info;
8102 struct btrfs_extent_item *extent_item;
8103 struct btrfs_tree_block_info *block_info;
8104 struct btrfs_extent_inline_ref *iref;
8105 struct btrfs_path *path;
8106 struct extent_buffer *leaf;
8107 u32 size = sizeof(*extent_item) + sizeof(*iref);
8108 u64 num_bytes = ins->offset;
8109 bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
8110 SKINNY_METADATA);
8111
8112 if (!skinny_metadata)
8113 size += sizeof(*block_info);
8114
8115 path = btrfs_alloc_path();
8116 if (!path) {
8117 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
8118 root->nodesize);
8119 return -ENOMEM;
8120 }
8121
8122 path->leave_spinning = 1;
8123 ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
8124 ins, size);
8125 if (ret) {
8126 btrfs_free_path(path);
8127 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
8128 root->nodesize);
8129 return ret;
8130 }
8131
8132 leaf = path->nodes[0];
8133 extent_item = btrfs_item_ptr(leaf, path->slots[0],
8134 struct btrfs_extent_item);
8135 btrfs_set_extent_refs(leaf, extent_item, 1);
8136 btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8137 btrfs_set_extent_flags(leaf, extent_item,
8138 flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
8139
8140 if (skinny_metadata) {
8141 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8142 num_bytes = root->nodesize;
8143 } else {
8144 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
8145 btrfs_set_tree_block_key(leaf, block_info, key);
8146 btrfs_set_tree_block_level(leaf, block_info, level);
8147 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
8148 }
8149
8150 if (parent > 0) {
8151 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
8152 btrfs_set_extent_inline_ref_type(leaf, iref,
8153 BTRFS_SHARED_BLOCK_REF_KEY);
8154 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
8155 } else {
8156 btrfs_set_extent_inline_ref_type(leaf, iref,
8157 BTRFS_TREE_BLOCK_REF_KEY);
8158 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
8159 }
8160
8161 btrfs_mark_buffer_dirty(leaf);
8162 btrfs_free_path(path);
8163
8164 ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
8165 num_bytes);
8166 if (ret)
8167 return ret;
8168
8169 ret = update_block_group(trans, root, ins->objectid, root->nodesize,
8170 1);
8171 if (ret) { /* -ENOENT, logic error */
8172 btrfs_err(fs_info, "update block group failed for %llu %llu",
8173 ins->objectid, ins->offset);
8174 BUG();
8175 }
8176
8177 trace_btrfs_reserved_extent_alloc(root, ins->objectid, root->nodesize);
8178 return ret;
8179 }
8180
8181 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8182 struct btrfs_root *root,
8183 u64 root_objectid, u64 owner,
8184 u64 offset, u64 ram_bytes,
8185 struct btrfs_key *ins)
8186 {
8187 int ret;
8188
8189 BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
8190
8191 ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
8192 ins->offset, 0,
8193 root_objectid, owner, offset,
8194 ram_bytes, BTRFS_ADD_DELAYED_EXTENT,
8195 NULL);
8196 return ret;
8197 }
8198
8199 /*
8200 * this is used by the tree logging recovery code. It records that
8201 * an extent has been allocated and makes sure to clear the free
8202 * space cache bits as well
8203 */
8204 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
8205 struct btrfs_root *root,
8206 u64 root_objectid, u64 owner, u64 offset,
8207 struct btrfs_key *ins)
8208 {
8209 int ret;
8210 struct btrfs_block_group_cache *block_group;
8211
8212 /*
8213 * Mixed block groups will exclude before processing the log so we only
8214 * need to do the exclude dance if this fs isn't mixed.
8215 */
8216 if (!btrfs_fs_incompat(root->fs_info, MIXED_GROUPS)) {
8217 ret = __exclude_logged_extent(root, ins->objectid, ins->offset);
8218 if (ret)
8219 return ret;
8220 }
8221
8222 block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
8223 if (!block_group)
8224 return -EINVAL;
8225
8226 ret = btrfs_update_reserved_bytes(block_group, ins->offset,
8227 RESERVE_ALLOC_NO_ACCOUNT, 0);
8228 BUG_ON(ret); /* logic error */
8229 ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
8230 0, owner, offset, ins, 1);
8231 btrfs_put_block_group(block_group);
8232 return ret;
8233 }
8234
8235 static struct extent_buffer *
8236 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
8237 u64 bytenr, int level)
8238 {
8239 struct extent_buffer *buf;
8240
8241 buf = btrfs_find_create_tree_block(root, bytenr);
8242 if (IS_ERR(buf))
8243 return buf;
8244
8245 btrfs_set_header_generation(buf, trans->transid);
8246 btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
8247 btrfs_tree_lock(buf);
8248 clean_tree_block(trans, root->fs_info, buf);
8249 clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
8250
8251 btrfs_set_lock_blocking(buf);
8252 set_extent_buffer_uptodate(buf);
8253
8254 if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
8255 buf->log_index = root->log_transid % 2;
8256 /*
8257 * we allow two log transactions at a time, use different
8258 * EXENT bit to differentiate dirty pages.
8259 */
8260 if (buf->log_index == 0)
8261 set_extent_dirty(&root->dirty_log_pages, buf->start,
8262 buf->start + buf->len - 1, GFP_NOFS);
8263 else
8264 set_extent_new(&root->dirty_log_pages, buf->start,
8265 buf->start + buf->len - 1);
8266 } else {
8267 buf->log_index = -1;
8268 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
8269 buf->start + buf->len - 1, GFP_NOFS);
8270 }
8271 trans->dirty = true;
8272 /* this returns a buffer locked for blocking */
8273 return buf;
8274 }
8275
8276 static struct btrfs_block_rsv *
8277 use_block_rsv(struct btrfs_trans_handle *trans,
8278 struct btrfs_root *root, u32 blocksize)
8279 {
8280 struct btrfs_block_rsv *block_rsv;
8281 struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
8282 int ret;
8283 bool global_updated = false;
8284
8285 block_rsv = get_block_rsv(trans, root);
8286
8287 if (unlikely(block_rsv->size == 0))
8288 goto try_reserve;
8289 again:
8290 ret = block_rsv_use_bytes(block_rsv, blocksize);
8291 if (!ret)
8292 return block_rsv;
8293
8294 if (block_rsv->failfast)
8295 return ERR_PTR(ret);
8296
8297 if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
8298 global_updated = true;
8299 update_global_block_rsv(root->fs_info);
8300 goto again;
8301 }
8302
8303 if (btrfs_test_opt(root->fs_info, ENOSPC_DEBUG)) {
8304 static DEFINE_RATELIMIT_STATE(_rs,
8305 DEFAULT_RATELIMIT_INTERVAL * 10,
8306 /*DEFAULT_RATELIMIT_BURST*/ 1);
8307 if (__ratelimit(&_rs))
8308 WARN(1, KERN_DEBUG
8309 "BTRFS: block rsv returned %d\n", ret);
8310 }
8311 try_reserve:
8312 ret = reserve_metadata_bytes(root, block_rsv, blocksize,
8313 BTRFS_RESERVE_NO_FLUSH);
8314 if (!ret)
8315 return block_rsv;
8316 /*
8317 * If we couldn't reserve metadata bytes try and use some from
8318 * the global reserve if its space type is the same as the global
8319 * reservation.
8320 */
8321 if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
8322 block_rsv->space_info == global_rsv->space_info) {
8323 ret = block_rsv_use_bytes(global_rsv, blocksize);
8324 if (!ret)
8325 return global_rsv;
8326 }
8327 return ERR_PTR(ret);
8328 }
8329
8330 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
8331 struct btrfs_block_rsv *block_rsv, u32 blocksize)
8332 {
8333 block_rsv_add_bytes(block_rsv, blocksize, 0);
8334 block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
8335 }
8336
8337 /*
8338 * finds a free extent and does all the dirty work required for allocation
8339 * returns the tree buffer or an ERR_PTR on error.
8340 */
8341 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
8342 struct btrfs_root *root,
8343 u64 parent, u64 root_objectid,
8344 struct btrfs_disk_key *key, int level,
8345 u64 hint, u64 empty_size)
8346 {
8347 struct btrfs_key ins;
8348 struct btrfs_block_rsv *block_rsv;
8349 struct extent_buffer *buf;
8350 struct btrfs_delayed_extent_op *extent_op;
8351 u64 flags = 0;
8352 int ret;
8353 u32 blocksize = root->nodesize;
8354 bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
8355 SKINNY_METADATA);
8356
8357 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
8358 if (btrfs_is_testing(root->fs_info)) {
8359 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
8360 level);
8361 if (!IS_ERR(buf))
8362 root->alloc_bytenr += blocksize;
8363 return buf;
8364 }
8365 #endif
8366
8367 block_rsv = use_block_rsv(trans, root, blocksize);
8368 if (IS_ERR(block_rsv))
8369 return ERR_CAST(block_rsv);
8370
8371 ret = btrfs_reserve_extent(root, blocksize, blocksize,
8372 empty_size, hint, &ins, 0, 0);
8373 if (ret)
8374 goto out_unuse;
8375
8376 buf = btrfs_init_new_buffer(trans, root, ins.objectid, level);
8377 if (IS_ERR(buf)) {
8378 ret = PTR_ERR(buf);
8379 goto out_free_reserved;
8380 }
8381
8382 if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
8383 if (parent == 0)
8384 parent = ins.objectid;
8385 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
8386 } else
8387 BUG_ON(parent > 0);
8388
8389 if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
8390 extent_op = btrfs_alloc_delayed_extent_op();
8391 if (!extent_op) {
8392 ret = -ENOMEM;
8393 goto out_free_buf;
8394 }
8395 if (key)
8396 memcpy(&extent_op->key, key, sizeof(extent_op->key));
8397 else
8398 memset(&extent_op->key, 0, sizeof(extent_op->key));
8399 extent_op->flags_to_set = flags;
8400 extent_op->update_key = skinny_metadata ? false : true;
8401 extent_op->update_flags = true;
8402 extent_op->is_data = false;
8403 extent_op->level = level;
8404
8405 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
8406 ins.objectid, ins.offset,
8407 parent, root_objectid, level,
8408 BTRFS_ADD_DELAYED_EXTENT,
8409 extent_op);
8410 if (ret)
8411 goto out_free_delayed;
8412 }
8413 return buf;
8414
8415 out_free_delayed:
8416 btrfs_free_delayed_extent_op(extent_op);
8417 out_free_buf:
8418 free_extent_buffer(buf);
8419 out_free_reserved:
8420 btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 0);
8421 out_unuse:
8422 unuse_block_rsv(root->fs_info, block_rsv, blocksize);
8423 return ERR_PTR(ret);
8424 }
8425
8426 struct walk_control {
8427 u64 refs[BTRFS_MAX_LEVEL];
8428 u64 flags[BTRFS_MAX_LEVEL];
8429 struct btrfs_key update_progress;
8430 int stage;
8431 int level;
8432 int shared_level;
8433 int update_ref;
8434 int keep_locks;
8435 int reada_slot;
8436 int reada_count;
8437 int for_reloc;
8438 };
8439
8440 #define DROP_REFERENCE 1
8441 #define UPDATE_BACKREF 2
8442
8443 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
8444 struct btrfs_root *root,
8445 struct walk_control *wc,
8446 struct btrfs_path *path)
8447 {
8448 u64 bytenr;
8449 u64 generation;
8450 u64 refs;
8451 u64 flags;
8452 u32 nritems;
8453 u32 blocksize;
8454 struct btrfs_key key;
8455 struct extent_buffer *eb;
8456 int ret;
8457 int slot;
8458 int nread = 0;
8459
8460 if (path->slots[wc->level] < wc->reada_slot) {
8461 wc->reada_count = wc->reada_count * 2 / 3;
8462 wc->reada_count = max(wc->reada_count, 2);
8463 } else {
8464 wc->reada_count = wc->reada_count * 3 / 2;
8465 wc->reada_count = min_t(int, wc->reada_count,
8466 BTRFS_NODEPTRS_PER_BLOCK(root));
8467 }
8468
8469 eb = path->nodes[wc->level];
8470 nritems = btrfs_header_nritems(eb);
8471 blocksize = root->nodesize;
8472
8473 for (slot = path->slots[wc->level]; slot < nritems; slot++) {
8474 if (nread >= wc->reada_count)
8475 break;
8476
8477 cond_resched();
8478 bytenr = btrfs_node_blockptr(eb, slot);
8479 generation = btrfs_node_ptr_generation(eb, slot);
8480
8481 if (slot == path->slots[wc->level])
8482 goto reada;
8483
8484 if (wc->stage == UPDATE_BACKREF &&
8485 generation <= root->root_key.offset)
8486 continue;
8487
8488 /* We don't lock the tree block, it's OK to be racy here */
8489 ret = btrfs_lookup_extent_info(trans, root, bytenr,
8490 wc->level - 1, 1, &refs,
8491 &flags);
8492 /* We don't care about errors in readahead. */
8493 if (ret < 0)
8494 continue;
8495 BUG_ON(refs == 0);
8496
8497 if (wc->stage == DROP_REFERENCE) {
8498 if (refs == 1)
8499 goto reada;
8500
8501 if (wc->level == 1 &&
8502 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8503 continue;
8504 if (!wc->update_ref ||
8505 generation <= root->root_key.offset)
8506 continue;
8507 btrfs_node_key_to_cpu(eb, &key, slot);
8508 ret = btrfs_comp_cpu_keys(&key,
8509 &wc->update_progress);
8510 if (ret < 0)
8511 continue;
8512 } else {
8513 if (wc->level == 1 &&
8514 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8515 continue;
8516 }
8517 reada:
8518 readahead_tree_block(root, bytenr);
8519 nread++;
8520 }
8521 wc->reada_slot = slot;
8522 }
8523
8524 /*
8525 * These may not be seen by the usual inc/dec ref code so we have to
8526 * add them here.
8527 */
8528 static int record_one_subtree_extent(struct btrfs_trans_handle *trans,
8529 struct btrfs_root *root, u64 bytenr,
8530 u64 num_bytes)
8531 {
8532 struct btrfs_qgroup_extent_record *qrecord;
8533 struct btrfs_delayed_ref_root *delayed_refs;
8534
8535 qrecord = kmalloc(sizeof(*qrecord), GFP_NOFS);
8536 if (!qrecord)
8537 return -ENOMEM;
8538
8539 qrecord->bytenr = bytenr;
8540 qrecord->num_bytes = num_bytes;
8541 qrecord->old_roots = NULL;
8542
8543 delayed_refs = &trans->transaction->delayed_refs;
8544 spin_lock(&delayed_refs->lock);
8545 if (btrfs_qgroup_insert_dirty_extent(trans->fs_info,
8546 delayed_refs, qrecord))
8547 kfree(qrecord);
8548 spin_unlock(&delayed_refs->lock);
8549
8550 return 0;
8551 }
8552
8553 static int account_leaf_items(struct btrfs_trans_handle *trans,
8554 struct btrfs_root *root,
8555 struct extent_buffer *eb)
8556 {
8557 int nr = btrfs_header_nritems(eb);
8558 int i, extent_type, ret;
8559 struct btrfs_key key;
8560 struct btrfs_file_extent_item *fi;
8561 u64 bytenr, num_bytes;
8562
8563 /* We can be called directly from walk_up_proc() */
8564 if (!root->fs_info->quota_enabled)
8565 return 0;
8566
8567 for (i = 0; i < nr; i++) {
8568 btrfs_item_key_to_cpu(eb, &key, i);
8569
8570 if (key.type != BTRFS_EXTENT_DATA_KEY)
8571 continue;
8572
8573 fi = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
8574 /* filter out non qgroup-accountable extents */
8575 extent_type = btrfs_file_extent_type(eb, fi);
8576
8577 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
8578 continue;
8579
8580 bytenr = btrfs_file_extent_disk_bytenr(eb, fi);
8581 if (!bytenr)
8582 continue;
8583
8584 num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
8585
8586 ret = record_one_subtree_extent(trans, root, bytenr, num_bytes);
8587 if (ret)
8588 return ret;
8589 }
8590 return 0;
8591 }
8592
8593 /*
8594 * Walk up the tree from the bottom, freeing leaves and any interior
8595 * nodes which have had all slots visited. If a node (leaf or
8596 * interior) is freed, the node above it will have it's slot
8597 * incremented. The root node will never be freed.
8598 *
8599 * At the end of this function, we should have a path which has all
8600 * slots incremented to the next position for a search. If we need to
8601 * read a new node it will be NULL and the node above it will have the
8602 * correct slot selected for a later read.
8603 *
8604 * If we increment the root nodes slot counter past the number of
8605 * elements, 1 is returned to signal completion of the search.
8606 */
8607 static int adjust_slots_upwards(struct btrfs_root *root,
8608 struct btrfs_path *path, int root_level)
8609 {
8610 int level = 0;
8611 int nr, slot;
8612 struct extent_buffer *eb;
8613
8614 if (root_level == 0)
8615 return 1;
8616
8617 while (level <= root_level) {
8618 eb = path->nodes[level];
8619 nr = btrfs_header_nritems(eb);
8620 path->slots[level]++;
8621 slot = path->slots[level];
8622 if (slot >= nr || level == 0) {
8623 /*
8624 * Don't free the root - we will detect this
8625 * condition after our loop and return a
8626 * positive value for caller to stop walking the tree.
8627 */
8628 if (level != root_level) {
8629 btrfs_tree_unlock_rw(eb, path->locks[level]);
8630 path->locks[level] = 0;
8631
8632 free_extent_buffer(eb);
8633 path->nodes[level] = NULL;
8634 path->slots[level] = 0;
8635 }
8636 } else {
8637 /*
8638 * We have a valid slot to walk back down
8639 * from. Stop here so caller can process these
8640 * new nodes.
8641 */
8642 break;
8643 }
8644
8645 level++;
8646 }
8647
8648 eb = path->nodes[root_level];
8649 if (path->slots[root_level] >= btrfs_header_nritems(eb))
8650 return 1;
8651
8652 return 0;
8653 }
8654
8655 /*
8656 * root_eb is the subtree root and is locked before this function is called.
8657 */
8658 static int account_shared_subtree(struct btrfs_trans_handle *trans,
8659 struct btrfs_root *root,
8660 struct extent_buffer *root_eb,
8661 u64 root_gen,
8662 int root_level)
8663 {
8664 int ret = 0;
8665 int level;
8666 struct extent_buffer *eb = root_eb;
8667 struct btrfs_path *path = NULL;
8668
8669 BUG_ON(root_level < 0 || root_level > BTRFS_MAX_LEVEL);
8670 BUG_ON(root_eb == NULL);
8671
8672 if (!root->fs_info->quota_enabled)
8673 return 0;
8674
8675 if (!extent_buffer_uptodate(root_eb)) {
8676 ret = btrfs_read_buffer(root_eb, root_gen);
8677 if (ret)
8678 goto out;
8679 }
8680
8681 if (root_level == 0) {
8682 ret = account_leaf_items(trans, root, root_eb);
8683 goto out;
8684 }
8685
8686 path = btrfs_alloc_path();
8687 if (!path)
8688 return -ENOMEM;
8689
8690 /*
8691 * Walk down the tree. Missing extent blocks are filled in as
8692 * we go. Metadata is accounted every time we read a new
8693 * extent block.
8694 *
8695 * When we reach a leaf, we account for file extent items in it,
8696 * walk back up the tree (adjusting slot pointers as we go)
8697 * and restart the search process.
8698 */
8699 extent_buffer_get(root_eb); /* For path */
8700 path->nodes[root_level] = root_eb;
8701 path->slots[root_level] = 0;
8702 path->locks[root_level] = 0; /* so release_path doesn't try to unlock */
8703 walk_down:
8704 level = root_level;
8705 while (level >= 0) {
8706 if (path->nodes[level] == NULL) {
8707 int parent_slot;
8708 u64 child_gen;
8709 u64 child_bytenr;
8710
8711 /* We need to get child blockptr/gen from
8712 * parent before we can read it. */
8713 eb = path->nodes[level + 1];
8714 parent_slot = path->slots[level + 1];
8715 child_bytenr = btrfs_node_blockptr(eb, parent_slot);
8716 child_gen = btrfs_node_ptr_generation(eb, parent_slot);
8717
8718 eb = read_tree_block(root, child_bytenr, child_gen);
8719 if (IS_ERR(eb)) {
8720 ret = PTR_ERR(eb);
8721 goto out;
8722 } else if (!extent_buffer_uptodate(eb)) {
8723 free_extent_buffer(eb);
8724 ret = -EIO;
8725 goto out;
8726 }
8727
8728 path->nodes[level] = eb;
8729 path->slots[level] = 0;
8730
8731 btrfs_tree_read_lock(eb);
8732 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
8733 path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
8734
8735 ret = record_one_subtree_extent(trans, root, child_bytenr,
8736 root->nodesize);
8737 if (ret)
8738 goto out;
8739 }
8740
8741 if (level == 0) {
8742 ret = account_leaf_items(trans, root, path->nodes[level]);
8743 if (ret)
8744 goto out;
8745
8746 /* Nonzero return here means we completed our search */
8747 ret = adjust_slots_upwards(root, path, root_level);
8748 if (ret)
8749 break;
8750
8751 /* Restart search with new slots */
8752 goto walk_down;
8753 }
8754
8755 level--;
8756 }
8757
8758 ret = 0;
8759 out:
8760 btrfs_free_path(path);
8761
8762 return ret;
8763 }
8764
8765 /*
8766 * helper to process tree block while walking down the tree.
8767 *
8768 * when wc->stage == UPDATE_BACKREF, this function updates
8769 * back refs for pointers in the block.
8770 *
8771 * NOTE: return value 1 means we should stop walking down.
8772 */
8773 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
8774 struct btrfs_root *root,
8775 struct btrfs_path *path,
8776 struct walk_control *wc, int lookup_info)
8777 {
8778 int level = wc->level;
8779 struct extent_buffer *eb = path->nodes[level];
8780 u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8781 int ret;
8782
8783 if (wc->stage == UPDATE_BACKREF &&
8784 btrfs_header_owner(eb) != root->root_key.objectid)
8785 return 1;
8786
8787 /*
8788 * when reference count of tree block is 1, it won't increase
8789 * again. once full backref flag is set, we never clear it.
8790 */
8791 if (lookup_info &&
8792 ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
8793 (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
8794 BUG_ON(!path->locks[level]);
8795 ret = btrfs_lookup_extent_info(trans, root,
8796 eb->start, level, 1,
8797 &wc->refs[level],
8798 &wc->flags[level]);
8799 BUG_ON(ret == -ENOMEM);
8800 if (ret)
8801 return ret;
8802 BUG_ON(wc->refs[level] == 0);
8803 }
8804
8805 if (wc->stage == DROP_REFERENCE) {
8806 if (wc->refs[level] > 1)
8807 return 1;
8808
8809 if (path->locks[level] && !wc->keep_locks) {
8810 btrfs_tree_unlock_rw(eb, path->locks[level]);
8811 path->locks[level] = 0;
8812 }
8813 return 0;
8814 }
8815
8816 /* wc->stage == UPDATE_BACKREF */
8817 if (!(wc->flags[level] & flag)) {
8818 BUG_ON(!path->locks[level]);
8819 ret = btrfs_inc_ref(trans, root, eb, 1);
8820 BUG_ON(ret); /* -ENOMEM */
8821 ret = btrfs_dec_ref(trans, root, eb, 0);
8822 BUG_ON(ret); /* -ENOMEM */
8823 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
8824 eb->len, flag,
8825 btrfs_header_level(eb), 0);
8826 BUG_ON(ret); /* -ENOMEM */
8827 wc->flags[level] |= flag;
8828 }
8829
8830 /*
8831 * the block is shared by multiple trees, so it's not good to
8832 * keep the tree lock
8833 */
8834 if (path->locks[level] && level > 0) {
8835 btrfs_tree_unlock_rw(eb, path->locks[level]);
8836 path->locks[level] = 0;
8837 }
8838 return 0;
8839 }
8840
8841 /*
8842 * helper to process tree block pointer.
8843 *
8844 * when wc->stage == DROP_REFERENCE, this function checks
8845 * reference count of the block pointed to. if the block
8846 * is shared and we need update back refs for the subtree
8847 * rooted at the block, this function changes wc->stage to
8848 * UPDATE_BACKREF. if the block is shared and there is no
8849 * need to update back, this function drops the reference
8850 * to the block.
8851 *
8852 * NOTE: return value 1 means we should stop walking down.
8853 */
8854 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
8855 struct btrfs_root *root,
8856 struct btrfs_path *path,
8857 struct walk_control *wc, int *lookup_info)
8858 {
8859 u64 bytenr;
8860 u64 generation;
8861 u64 parent;
8862 u32 blocksize;
8863 struct btrfs_key key;
8864 struct extent_buffer *next;
8865 int level = wc->level;
8866 int reada = 0;
8867 int ret = 0;
8868 bool need_account = false;
8869
8870 generation = btrfs_node_ptr_generation(path->nodes[level],
8871 path->slots[level]);
8872 /*
8873 * if the lower level block was created before the snapshot
8874 * was created, we know there is no need to update back refs
8875 * for the subtree
8876 */
8877 if (wc->stage == UPDATE_BACKREF &&
8878 generation <= root->root_key.offset) {
8879 *lookup_info = 1;
8880 return 1;
8881 }
8882
8883 bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
8884 blocksize = root->nodesize;
8885
8886 next = btrfs_find_tree_block(root->fs_info, bytenr);
8887 if (!next) {
8888 next = btrfs_find_create_tree_block(root, bytenr);
8889 if (IS_ERR(next))
8890 return PTR_ERR(next);
8891
8892 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
8893 level - 1);
8894 reada = 1;
8895 }
8896 btrfs_tree_lock(next);
8897 btrfs_set_lock_blocking(next);
8898
8899 ret = btrfs_lookup_extent_info(trans, root, bytenr, level - 1, 1,
8900 &wc->refs[level - 1],
8901 &wc->flags[level - 1]);
8902 if (ret < 0) {
8903 btrfs_tree_unlock(next);
8904 return ret;
8905 }
8906
8907 if (unlikely(wc->refs[level - 1] == 0)) {
8908 btrfs_err(root->fs_info, "Missing references.");
8909 BUG();
8910 }
8911 *lookup_info = 0;
8912
8913 if (wc->stage == DROP_REFERENCE) {
8914 if (wc->refs[level - 1] > 1) {
8915 need_account = true;
8916 if (level == 1 &&
8917 (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8918 goto skip;
8919
8920 if (!wc->update_ref ||
8921 generation <= root->root_key.offset)
8922 goto skip;
8923
8924 btrfs_node_key_to_cpu(path->nodes[level], &key,
8925 path->slots[level]);
8926 ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
8927 if (ret < 0)
8928 goto skip;
8929
8930 wc->stage = UPDATE_BACKREF;
8931 wc->shared_level = level - 1;
8932 }
8933 } else {
8934 if (level == 1 &&
8935 (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8936 goto skip;
8937 }
8938
8939 if (!btrfs_buffer_uptodate(next, generation, 0)) {
8940 btrfs_tree_unlock(next);
8941 free_extent_buffer(next);
8942 next = NULL;
8943 *lookup_info = 1;
8944 }
8945
8946 if (!next) {
8947 if (reada && level == 1)
8948 reada_walk_down(trans, root, wc, path);
8949 next = read_tree_block(root, bytenr, generation);
8950 if (IS_ERR(next)) {
8951 return PTR_ERR(next);
8952 } else if (!extent_buffer_uptodate(next)) {
8953 free_extent_buffer(next);
8954 return -EIO;
8955 }
8956 btrfs_tree_lock(next);
8957 btrfs_set_lock_blocking(next);
8958 }
8959
8960 level--;
8961 BUG_ON(level != btrfs_header_level(next));
8962 path->nodes[level] = next;
8963 path->slots[level] = 0;
8964 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8965 wc->level = level;
8966 if (wc->level == 1)
8967 wc->reada_slot = 0;
8968 return 0;
8969 skip:
8970 wc->refs[level - 1] = 0;
8971 wc->flags[level - 1] = 0;
8972 if (wc->stage == DROP_REFERENCE) {
8973 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
8974 parent = path->nodes[level]->start;
8975 } else {
8976 BUG_ON(root->root_key.objectid !=
8977 btrfs_header_owner(path->nodes[level]));
8978 parent = 0;
8979 }
8980
8981 if (need_account) {
8982 ret = account_shared_subtree(trans, root, next,
8983 generation, level - 1);
8984 if (ret) {
8985 btrfs_err_rl(root->fs_info,
8986 "Error "
8987 "%d accounting shared subtree. Quota "
8988 "is out of sync, rescan required.",
8989 ret);
8990 }
8991 }
8992 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
8993 root->root_key.objectid, level - 1, 0);
8994 BUG_ON(ret); /* -ENOMEM */
8995 }
8996 btrfs_tree_unlock(next);
8997 free_extent_buffer(next);
8998 *lookup_info = 1;
8999 return 1;
9000 }
9001
9002 /*
9003 * helper to process tree block while walking up the tree.
9004 *
9005 * when wc->stage == DROP_REFERENCE, this function drops
9006 * reference count on the block.
9007 *
9008 * when wc->stage == UPDATE_BACKREF, this function changes
9009 * wc->stage back to DROP_REFERENCE if we changed wc->stage
9010 * to UPDATE_BACKREF previously while processing the block.
9011 *
9012 * NOTE: return value 1 means we should stop walking up.
9013 */
9014 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
9015 struct btrfs_root *root,
9016 struct btrfs_path *path,
9017 struct walk_control *wc)
9018 {
9019 int ret;
9020 int level = wc->level;
9021 struct extent_buffer *eb = path->nodes[level];
9022 u64 parent = 0;
9023
9024 if (wc->stage == UPDATE_BACKREF) {
9025 BUG_ON(wc->shared_level < level);
9026 if (level < wc->shared_level)
9027 goto out;
9028
9029 ret = find_next_key(path, level + 1, &wc->update_progress);
9030 if (ret > 0)
9031 wc->update_ref = 0;
9032
9033 wc->stage = DROP_REFERENCE;
9034 wc->shared_level = -1;
9035 path->slots[level] = 0;
9036
9037 /*
9038 * check reference count again if the block isn't locked.
9039 * we should start walking down the tree again if reference
9040 * count is one.
9041 */
9042 if (!path->locks[level]) {
9043 BUG_ON(level == 0);
9044 btrfs_tree_lock(eb);
9045 btrfs_set_lock_blocking(eb);
9046 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9047
9048 ret = btrfs_lookup_extent_info(trans, root,
9049 eb->start, level, 1,
9050 &wc->refs[level],
9051 &wc->flags[level]);
9052 if (ret < 0) {
9053 btrfs_tree_unlock_rw(eb, path->locks[level]);
9054 path->locks[level] = 0;
9055 return ret;
9056 }
9057 BUG_ON(wc->refs[level] == 0);
9058 if (wc->refs[level] == 1) {
9059 btrfs_tree_unlock_rw(eb, path->locks[level]);
9060 path->locks[level] = 0;
9061 return 1;
9062 }
9063 }
9064 }
9065
9066 /* wc->stage == DROP_REFERENCE */
9067 BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
9068
9069 if (wc->refs[level] == 1) {
9070 if (level == 0) {
9071 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
9072 ret = btrfs_dec_ref(trans, root, eb, 1);
9073 else
9074 ret = btrfs_dec_ref(trans, root, eb, 0);
9075 BUG_ON(ret); /* -ENOMEM */
9076 ret = account_leaf_items(trans, root, eb);
9077 if (ret) {
9078 btrfs_err_rl(root->fs_info,
9079 "error "
9080 "%d accounting leaf items. Quota "
9081 "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_path *path;
9199 struct btrfs_trans_handle *trans;
9200 struct btrfs_root *tree_root = root->fs_info->tree_root;
9201 struct btrfs_root_item *root_item = &root->root_item;
9202 struct walk_control *wc;
9203 struct btrfs_key key;
9204 int err = 0;
9205 int ret;
9206 int level;
9207 bool root_dropped = false;
9208
9209 btrfs_debug(root->fs_info, "Drop subvolume %llu", root->objectid);
9210
9211 path = btrfs_alloc_path();
9212 if (!path) {
9213 err = -ENOMEM;
9214 goto out;
9215 }
9216
9217 wc = kzalloc(sizeof(*wc), GFP_NOFS);
9218 if (!wc) {
9219 btrfs_free_path(path);
9220 err = -ENOMEM;
9221 goto out;
9222 }
9223
9224 trans = btrfs_start_transaction(tree_root, 0);
9225 if (IS_ERR(trans)) {
9226 err = PTR_ERR(trans);
9227 goto out_free;
9228 }
9229
9230 if (block_rsv)
9231 trans->block_rsv = block_rsv;
9232
9233 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
9234 level = btrfs_header_level(root->node);
9235 path->nodes[level] = btrfs_lock_root_node(root);
9236 btrfs_set_lock_blocking(path->nodes[level]);
9237 path->slots[level] = 0;
9238 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9239 memset(&wc->update_progress, 0,
9240 sizeof(wc->update_progress));
9241 } else {
9242 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
9243 memcpy(&wc->update_progress, &key,
9244 sizeof(wc->update_progress));
9245
9246 level = root_item->drop_level;
9247 BUG_ON(level == 0);
9248 path->lowest_level = level;
9249 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
9250 path->lowest_level = 0;
9251 if (ret < 0) {
9252 err = ret;
9253 goto out_end_trans;
9254 }
9255 WARN_ON(ret > 0);
9256
9257 /*
9258 * unlock our path, this is safe because only this
9259 * function is allowed to delete this snapshot
9260 */
9261 btrfs_unlock_up_safe(path, 0);
9262
9263 level = btrfs_header_level(root->node);
9264 while (1) {
9265 btrfs_tree_lock(path->nodes[level]);
9266 btrfs_set_lock_blocking(path->nodes[level]);
9267 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9268
9269 ret = btrfs_lookup_extent_info(trans, root,
9270 path->nodes[level]->start,
9271 level, 1, &wc->refs[level],
9272 &wc->flags[level]);
9273 if (ret < 0) {
9274 err = ret;
9275 goto out_end_trans;
9276 }
9277 BUG_ON(wc->refs[level] == 0);
9278
9279 if (level == root_item->drop_level)
9280 break;
9281
9282 btrfs_tree_unlock(path->nodes[level]);
9283 path->locks[level] = 0;
9284 WARN_ON(wc->refs[level] != 1);
9285 level--;
9286 }
9287 }
9288
9289 wc->level = level;
9290 wc->shared_level = -1;
9291 wc->stage = DROP_REFERENCE;
9292 wc->update_ref = update_ref;
9293 wc->keep_locks = 0;
9294 wc->for_reloc = for_reloc;
9295 wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
9296
9297 while (1) {
9298
9299 ret = walk_down_tree(trans, root, path, wc);
9300 if (ret < 0) {
9301 err = ret;
9302 break;
9303 }
9304
9305 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
9306 if (ret < 0) {
9307 err = ret;
9308 break;
9309 }
9310
9311 if (ret > 0) {
9312 BUG_ON(wc->stage != DROP_REFERENCE);
9313 break;
9314 }
9315
9316 if (wc->stage == DROP_REFERENCE) {
9317 level = wc->level;
9318 btrfs_node_key(path->nodes[level],
9319 &root_item->drop_progress,
9320 path->slots[level]);
9321 root_item->drop_level = level;
9322 }
9323
9324 BUG_ON(wc->level == 0);
9325 if (btrfs_should_end_transaction(trans, tree_root) ||
9326 (!for_reloc && btrfs_need_cleaner_sleep(root))) {
9327 ret = btrfs_update_root(trans, tree_root,
9328 &root->root_key,
9329 root_item);
9330 if (ret) {
9331 btrfs_abort_transaction(trans, ret);
9332 err = ret;
9333 goto out_end_trans;
9334 }
9335
9336 btrfs_end_transaction_throttle(trans, tree_root);
9337 if (!for_reloc && btrfs_need_cleaner_sleep(root)) {
9338 pr_debug("BTRFS: drop snapshot early exit\n");
9339 err = -EAGAIN;
9340 goto out_free;
9341 }
9342
9343 trans = btrfs_start_transaction(tree_root, 0);
9344 if (IS_ERR(trans)) {
9345 err = PTR_ERR(trans);
9346 goto out_free;
9347 }
9348 if (block_rsv)
9349 trans->block_rsv = block_rsv;
9350 }
9351 }
9352 btrfs_release_path(path);
9353 if (err)
9354 goto out_end_trans;
9355
9356 ret = btrfs_del_root(trans, tree_root, &root->root_key);
9357 if (ret) {
9358 btrfs_abort_transaction(trans, ret);
9359 goto out_end_trans;
9360 }
9361
9362 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
9363 ret = btrfs_find_root(tree_root, &root->root_key, path,
9364 NULL, NULL);
9365 if (ret < 0) {
9366 btrfs_abort_transaction(trans, ret);
9367 err = ret;
9368 goto out_end_trans;
9369 } else if (ret > 0) {
9370 /* if we fail to delete the orphan item this time
9371 * around, it'll get picked up the next time.
9372 *
9373 * The most common failure here is just -ENOENT.
9374 */
9375 btrfs_del_orphan_item(trans, tree_root,
9376 root->root_key.objectid);
9377 }
9378 }
9379
9380 if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
9381 btrfs_add_dropped_root(trans, root);
9382 } else {
9383 free_extent_buffer(root->node);
9384 free_extent_buffer(root->commit_root);
9385 btrfs_put_fs_root(root);
9386 }
9387 root_dropped = true;
9388 out_end_trans:
9389 btrfs_end_transaction_throttle(trans, tree_root);
9390 out_free:
9391 kfree(wc);
9392 btrfs_free_path(path);
9393 out:
9394 /*
9395 * So if we need to stop dropping the snapshot for whatever reason we
9396 * need to make sure to add it back to the dead root list so that we
9397 * keep trying to do the work later. This also cleans up roots if we
9398 * don't have it in the radix (like when we recover after a power fail
9399 * or unmount) so we don't leak memory.
9400 */
9401 if (!for_reloc && root_dropped == false)
9402 btrfs_add_dead_root(root);
9403 if (err && err != -EAGAIN)
9404 btrfs_handle_fs_error(root->fs_info, err, NULL);
9405 return err;
9406 }
9407
9408 /*
9409 * drop subtree rooted at tree block 'node'.
9410 *
9411 * NOTE: this function will unlock and release tree block 'node'
9412 * only used by relocation code
9413 */
9414 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
9415 struct btrfs_root *root,
9416 struct extent_buffer *node,
9417 struct extent_buffer *parent)
9418 {
9419 struct btrfs_path *path;
9420 struct walk_control *wc;
9421 int level;
9422 int parent_level;
9423 int ret = 0;
9424 int wret;
9425
9426 BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
9427
9428 path = btrfs_alloc_path();
9429 if (!path)
9430 return -ENOMEM;
9431
9432 wc = kzalloc(sizeof(*wc), GFP_NOFS);
9433 if (!wc) {
9434 btrfs_free_path(path);
9435 return -ENOMEM;
9436 }
9437
9438 btrfs_assert_tree_locked(parent);
9439 parent_level = btrfs_header_level(parent);
9440 extent_buffer_get(parent);
9441 path->nodes[parent_level] = parent;
9442 path->slots[parent_level] = btrfs_header_nritems(parent);
9443
9444 btrfs_assert_tree_locked(node);
9445 level = btrfs_header_level(node);
9446 path->nodes[level] = node;
9447 path->slots[level] = 0;
9448 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9449
9450 wc->refs[parent_level] = 1;
9451 wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
9452 wc->level = level;
9453 wc->shared_level = -1;
9454 wc->stage = DROP_REFERENCE;
9455 wc->update_ref = 0;
9456 wc->keep_locks = 1;
9457 wc->for_reloc = 1;
9458 wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
9459
9460 while (1) {
9461 wret = walk_down_tree(trans, root, path, wc);
9462 if (wret < 0) {
9463 ret = wret;
9464 break;
9465 }
9466
9467 wret = walk_up_tree(trans, root, path, wc, parent_level);
9468 if (wret < 0)
9469 ret = wret;
9470 if (wret != 0)
9471 break;
9472 }
9473
9474 kfree(wc);
9475 btrfs_free_path(path);
9476 return ret;
9477 }
9478
9479 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
9480 {
9481 u64 num_devices;
9482 u64 stripped;
9483
9484 /*
9485 * if restripe for this chunk_type is on pick target profile and
9486 * return, otherwise do the usual balance
9487 */
9488 stripped = get_restripe_target(root->fs_info, flags);
9489 if (stripped)
9490 return extended_to_chunk(stripped);
9491
9492 num_devices = root->fs_info->fs_devices->rw_devices;
9493
9494 stripped = BTRFS_BLOCK_GROUP_RAID0 |
9495 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
9496 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
9497
9498 if (num_devices == 1) {
9499 stripped |= BTRFS_BLOCK_GROUP_DUP;
9500 stripped = flags & ~stripped;
9501
9502 /* turn raid0 into single device chunks */
9503 if (flags & BTRFS_BLOCK_GROUP_RAID0)
9504 return stripped;
9505
9506 /* turn mirroring into duplication */
9507 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
9508 BTRFS_BLOCK_GROUP_RAID10))
9509 return stripped | BTRFS_BLOCK_GROUP_DUP;
9510 } else {
9511 /* they already had raid on here, just return */
9512 if (flags & stripped)
9513 return flags;
9514
9515 stripped |= BTRFS_BLOCK_GROUP_DUP;
9516 stripped = flags & ~stripped;
9517
9518 /* switch duplicated blocks with raid1 */
9519 if (flags & BTRFS_BLOCK_GROUP_DUP)
9520 return stripped | BTRFS_BLOCK_GROUP_RAID1;
9521
9522 /* this is drive concat, leave it alone */
9523 }
9524
9525 return flags;
9526 }
9527
9528 static int inc_block_group_ro(struct btrfs_block_group_cache *cache, int force)
9529 {
9530 struct btrfs_space_info *sinfo = cache->space_info;
9531 u64 num_bytes;
9532 u64 min_allocable_bytes;
9533 int ret = -ENOSPC;
9534
9535 /*
9536 * We need some metadata space and system metadata space for
9537 * allocating chunks in some corner cases until we force to set
9538 * it to be readonly.
9539 */
9540 if ((sinfo->flags &
9541 (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
9542 !force)
9543 min_allocable_bytes = SZ_1M;
9544 else
9545 min_allocable_bytes = 0;
9546
9547 spin_lock(&sinfo->lock);
9548 spin_lock(&cache->lock);
9549
9550 if (cache->ro) {
9551 cache->ro++;
9552 ret = 0;
9553 goto out;
9554 }
9555
9556 num_bytes = cache->key.offset - cache->reserved - cache->pinned -
9557 cache->bytes_super - btrfs_block_group_used(&cache->item);
9558
9559 if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
9560 sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
9561 min_allocable_bytes <= sinfo->total_bytes) {
9562 sinfo->bytes_readonly += num_bytes;
9563 cache->ro++;
9564 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
9565 ret = 0;
9566 }
9567 out:
9568 spin_unlock(&cache->lock);
9569 spin_unlock(&sinfo->lock);
9570 return ret;
9571 }
9572
9573 int btrfs_inc_block_group_ro(struct btrfs_root *root,
9574 struct btrfs_block_group_cache *cache)
9575
9576 {
9577 struct btrfs_trans_handle *trans;
9578 u64 alloc_flags;
9579 int ret;
9580
9581 again:
9582 trans = btrfs_join_transaction(root);
9583 if (IS_ERR(trans))
9584 return PTR_ERR(trans);
9585
9586 /*
9587 * we're not allowed to set block groups readonly after the dirty
9588 * block groups cache has started writing. If it already started,
9589 * back off and let this transaction commit
9590 */
9591 mutex_lock(&root->fs_info->ro_block_group_mutex);
9592 if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
9593 u64 transid = trans->transid;
9594
9595 mutex_unlock(&root->fs_info->ro_block_group_mutex);
9596 btrfs_end_transaction(trans, root);
9597
9598 ret = btrfs_wait_for_commit(root, transid);
9599 if (ret)
9600 return ret;
9601 goto again;
9602 }
9603
9604 /*
9605 * if we are changing raid levels, try to allocate a corresponding
9606 * block group with the new raid level.
9607 */
9608 alloc_flags = update_block_group_flags(root, cache->flags);
9609 if (alloc_flags != cache->flags) {
9610 ret = do_chunk_alloc(trans, root, alloc_flags,
9611 CHUNK_ALLOC_FORCE);
9612 /*
9613 * ENOSPC is allowed here, we may have enough space
9614 * already allocated at the new raid level to
9615 * carry on
9616 */
9617 if (ret == -ENOSPC)
9618 ret = 0;
9619 if (ret < 0)
9620 goto out;
9621 }
9622
9623 ret = inc_block_group_ro(cache, 0);
9624 if (!ret)
9625 goto out;
9626 alloc_flags = get_alloc_profile(root, cache->space_info->flags);
9627 ret = do_chunk_alloc(trans, root, alloc_flags,
9628 CHUNK_ALLOC_FORCE);
9629 if (ret < 0)
9630 goto out;
9631 ret = inc_block_group_ro(cache, 0);
9632 out:
9633 if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
9634 alloc_flags = update_block_group_flags(root, cache->flags);
9635 lock_chunks(root->fs_info->chunk_root);
9636 check_system_chunk(trans, root, alloc_flags);
9637 unlock_chunks(root->fs_info->chunk_root);
9638 }
9639 mutex_unlock(&root->fs_info->ro_block_group_mutex);
9640
9641 btrfs_end_transaction(trans, root);
9642 return ret;
9643 }
9644
9645 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
9646 struct btrfs_root *root, u64 type)
9647 {
9648 u64 alloc_flags = get_alloc_profile(root, type);
9649 return do_chunk_alloc(trans, root, alloc_flags,
9650 CHUNK_ALLOC_FORCE);
9651 }
9652
9653 /*
9654 * helper to account the unused space of all the readonly block group in the
9655 * space_info. takes mirrors into account.
9656 */
9657 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
9658 {
9659 struct btrfs_block_group_cache *block_group;
9660 u64 free_bytes = 0;
9661 int factor;
9662
9663 /* It's df, we don't care if it's racy */
9664 if (list_empty(&sinfo->ro_bgs))
9665 return 0;
9666
9667 spin_lock(&sinfo->lock);
9668 list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
9669 spin_lock(&block_group->lock);
9670
9671 if (!block_group->ro) {
9672 spin_unlock(&block_group->lock);
9673 continue;
9674 }
9675
9676 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
9677 BTRFS_BLOCK_GROUP_RAID10 |
9678 BTRFS_BLOCK_GROUP_DUP))
9679 factor = 2;
9680 else
9681 factor = 1;
9682
9683 free_bytes += (block_group->key.offset -
9684 btrfs_block_group_used(&block_group->item)) *
9685 factor;
9686
9687 spin_unlock(&block_group->lock);
9688 }
9689 spin_unlock(&sinfo->lock);
9690
9691 return free_bytes;
9692 }
9693
9694 void btrfs_dec_block_group_ro(struct btrfs_root *root,
9695 struct btrfs_block_group_cache *cache)
9696 {
9697 struct btrfs_space_info *sinfo = cache->space_info;
9698 u64 num_bytes;
9699
9700 BUG_ON(!cache->ro);
9701
9702 spin_lock(&sinfo->lock);
9703 spin_lock(&cache->lock);
9704 if (!--cache->ro) {
9705 num_bytes = cache->key.offset - cache->reserved -
9706 cache->pinned - cache->bytes_super -
9707 btrfs_block_group_used(&cache->item);
9708 sinfo->bytes_readonly -= num_bytes;
9709 list_del_init(&cache->ro_list);
9710 }
9711 spin_unlock(&cache->lock);
9712 spin_unlock(&sinfo->lock);
9713 }
9714
9715 /*
9716 * checks to see if its even possible to relocate this block group.
9717 *
9718 * @return - -1 if it's not a good idea to relocate this block group, 0 if its
9719 * ok to go ahead and try.
9720 */
9721 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
9722 {
9723 struct btrfs_block_group_cache *block_group;
9724 struct btrfs_space_info *space_info;
9725 struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
9726 struct btrfs_device *device;
9727 struct btrfs_trans_handle *trans;
9728 u64 min_free;
9729 u64 dev_min = 1;
9730 u64 dev_nr = 0;
9731 u64 target;
9732 int debug;
9733 int index;
9734 int full = 0;
9735 int ret = 0;
9736
9737 debug = btrfs_test_opt(root->fs_info, ENOSPC_DEBUG);
9738
9739 block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
9740
9741 /* odd, couldn't find the block group, leave it alone */
9742 if (!block_group) {
9743 if (debug)
9744 btrfs_warn(root->fs_info,
9745 "can't find block group for bytenr %llu",
9746 bytenr);
9747 return -1;
9748 }
9749
9750 min_free = btrfs_block_group_used(&block_group->item);
9751
9752 /* no bytes used, we're good */
9753 if (!min_free)
9754 goto out;
9755
9756 space_info = block_group->space_info;
9757 spin_lock(&space_info->lock);
9758
9759 full = space_info->full;
9760
9761 /*
9762 * if this is the last block group we have in this space, we can't
9763 * relocate it unless we're able to allocate a new chunk below.
9764 *
9765 * Otherwise, we need to make sure we have room in the space to handle
9766 * all of the extents from this block group. If we can, we're good
9767 */
9768 if ((space_info->total_bytes != block_group->key.offset) &&
9769 (space_info->bytes_used + space_info->bytes_reserved +
9770 space_info->bytes_pinned + space_info->bytes_readonly +
9771 min_free < space_info->total_bytes)) {
9772 spin_unlock(&space_info->lock);
9773 goto out;
9774 }
9775 spin_unlock(&space_info->lock);
9776
9777 /*
9778 * ok we don't have enough space, but maybe we have free space on our
9779 * devices to allocate new chunks for relocation, so loop through our
9780 * alloc devices and guess if we have enough space. if this block
9781 * group is going to be restriped, run checks against the target
9782 * profile instead of the current one.
9783 */
9784 ret = -1;
9785
9786 /*
9787 * index:
9788 * 0: raid10
9789 * 1: raid1
9790 * 2: dup
9791 * 3: raid0
9792 * 4: single
9793 */
9794 target = get_restripe_target(root->fs_info, block_group->flags);
9795 if (target) {
9796 index = __get_raid_index(extended_to_chunk(target));
9797 } else {
9798 /*
9799 * this is just a balance, so if we were marked as full
9800 * we know there is no space for a new chunk
9801 */
9802 if (full) {
9803 if (debug)
9804 btrfs_warn(root->fs_info,
9805 "no space to alloc new chunk for block group %llu",
9806 block_group->key.objectid);
9807 goto out;
9808 }
9809
9810 index = get_block_group_index(block_group);
9811 }
9812
9813 if (index == BTRFS_RAID_RAID10) {
9814 dev_min = 4;
9815 /* Divide by 2 */
9816 min_free >>= 1;
9817 } else if (index == BTRFS_RAID_RAID1) {
9818 dev_min = 2;
9819 } else if (index == BTRFS_RAID_DUP) {
9820 /* Multiply by 2 */
9821 min_free <<= 1;
9822 } else if (index == BTRFS_RAID_RAID0) {
9823 dev_min = fs_devices->rw_devices;
9824 min_free = div64_u64(min_free, dev_min);
9825 }
9826
9827 /* We need to do this so that we can look at pending chunks */
9828 trans = btrfs_join_transaction(root);
9829 if (IS_ERR(trans)) {
9830 ret = PTR_ERR(trans);
9831 goto out;
9832 }
9833
9834 mutex_lock(&root->fs_info->chunk_mutex);
9835 list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
9836 u64 dev_offset;
9837
9838 /*
9839 * check to make sure we can actually find a chunk with enough
9840 * space to fit our block group in.
9841 */
9842 if (device->total_bytes > device->bytes_used + min_free &&
9843 !device->is_tgtdev_for_dev_replace) {
9844 ret = find_free_dev_extent(trans, device, min_free,
9845 &dev_offset, NULL);
9846 if (!ret)
9847 dev_nr++;
9848
9849 if (dev_nr >= dev_min)
9850 break;
9851
9852 ret = -1;
9853 }
9854 }
9855 if (debug && ret == -1)
9856 btrfs_warn(root->fs_info,
9857 "no space to allocate a new chunk for block group %llu",
9858 block_group->key.objectid);
9859 mutex_unlock(&root->fs_info->chunk_mutex);
9860 btrfs_end_transaction(trans, root);
9861 out:
9862 btrfs_put_block_group(block_group);
9863 return ret;
9864 }
9865
9866 static int find_first_block_group(struct btrfs_root *root,
9867 struct btrfs_path *path, struct btrfs_key *key)
9868 {
9869 int ret = 0;
9870 struct btrfs_key found_key;
9871 struct extent_buffer *leaf;
9872 int slot;
9873
9874 ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
9875 if (ret < 0)
9876 goto out;
9877
9878 while (1) {
9879 slot = path->slots[0];
9880 leaf = path->nodes[0];
9881 if (slot >= btrfs_header_nritems(leaf)) {
9882 ret = btrfs_next_leaf(root, path);
9883 if (ret == 0)
9884 continue;
9885 if (ret < 0)
9886 goto out;
9887 break;
9888 }
9889 btrfs_item_key_to_cpu(leaf, &found_key, slot);
9890
9891 if (found_key.objectid >= key->objectid &&
9892 found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
9893 struct extent_map_tree *em_tree;
9894 struct extent_map *em;
9895
9896 em_tree = &root->fs_info->mapping_tree.map_tree;
9897 read_lock(&em_tree->lock);
9898 em = lookup_extent_mapping(em_tree, found_key.objectid,
9899 found_key.offset);
9900 read_unlock(&em_tree->lock);
9901 if (!em) {
9902 btrfs_err(root->fs_info,
9903 "logical %llu len %llu found bg but no related chunk",
9904 found_key.objectid, found_key.offset);
9905 ret = -ENOENT;
9906 } else {
9907 ret = 0;
9908 }
9909 goto out;
9910 }
9911 path->slots[0]++;
9912 }
9913 out:
9914 return ret;
9915 }
9916
9917 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
9918 {
9919 struct btrfs_block_group_cache *block_group;
9920 u64 last = 0;
9921
9922 while (1) {
9923 struct inode *inode;
9924
9925 block_group = btrfs_lookup_first_block_group(info, last);
9926 while (block_group) {
9927 spin_lock(&block_group->lock);
9928 if (block_group->iref)
9929 break;
9930 spin_unlock(&block_group->lock);
9931 block_group = next_block_group(info->tree_root,
9932 block_group);
9933 }
9934 if (!block_group) {
9935 if (last == 0)
9936 break;
9937 last = 0;
9938 continue;
9939 }
9940
9941 inode = block_group->inode;
9942 block_group->iref = 0;
9943 block_group->inode = NULL;
9944 spin_unlock(&block_group->lock);
9945 iput(inode);
9946 last = block_group->key.objectid + block_group->key.offset;
9947 btrfs_put_block_group(block_group);
9948 }
9949 }
9950
9951 int btrfs_free_block_groups(struct btrfs_fs_info *info)
9952 {
9953 struct btrfs_block_group_cache *block_group;
9954 struct btrfs_space_info *space_info;
9955 struct btrfs_caching_control *caching_ctl;
9956 struct rb_node *n;
9957
9958 down_write(&info->commit_root_sem);
9959 while (!list_empty(&info->caching_block_groups)) {
9960 caching_ctl = list_entry(info->caching_block_groups.next,
9961 struct btrfs_caching_control, list);
9962 list_del(&caching_ctl->list);
9963 put_caching_control(caching_ctl);
9964 }
9965 up_write(&info->commit_root_sem);
9966
9967 spin_lock(&info->unused_bgs_lock);
9968 while (!list_empty(&info->unused_bgs)) {
9969 block_group = list_first_entry(&info->unused_bgs,
9970 struct btrfs_block_group_cache,
9971 bg_list);
9972 list_del_init(&block_group->bg_list);
9973 btrfs_put_block_group(block_group);
9974 }
9975 spin_unlock(&info->unused_bgs_lock);
9976
9977 spin_lock(&info->block_group_cache_lock);
9978 while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
9979 block_group = rb_entry(n, struct btrfs_block_group_cache,
9980 cache_node);
9981 rb_erase(&block_group->cache_node,
9982 &info->block_group_cache_tree);
9983 RB_CLEAR_NODE(&block_group->cache_node);
9984 spin_unlock(&info->block_group_cache_lock);
9985
9986 down_write(&block_group->space_info->groups_sem);
9987 list_del(&block_group->list);
9988 up_write(&block_group->space_info->groups_sem);
9989
9990 if (block_group->cached == BTRFS_CACHE_STARTED)
9991 wait_block_group_cache_done(block_group);
9992
9993 /*
9994 * We haven't cached this block group, which means we could
9995 * possibly have excluded extents on this block group.
9996 */
9997 if (block_group->cached == BTRFS_CACHE_NO ||
9998 block_group->cached == BTRFS_CACHE_ERROR)
9999 free_excluded_extents(info->extent_root, block_group);
10000
10001 btrfs_remove_free_space_cache(block_group);
10002 btrfs_put_block_group(block_group);
10003
10004 spin_lock(&info->block_group_cache_lock);
10005 }
10006 spin_unlock(&info->block_group_cache_lock);
10007
10008 /* now that all the block groups are freed, go through and
10009 * free all the space_info structs. This is only called during
10010 * the final stages of unmount, and so we know nobody is
10011 * using them. We call synchronize_rcu() once before we start,
10012 * just to be on the safe side.
10013 */
10014 synchronize_rcu();
10015
10016 release_global_block_rsv(info);
10017
10018 while (!list_empty(&info->space_info)) {
10019 int i;
10020
10021 space_info = list_entry(info->space_info.next,
10022 struct btrfs_space_info,
10023 list);
10024
10025 /*
10026 * Do not hide this behind enospc_debug, this is actually
10027 * important and indicates a real bug if this happens.
10028 */
10029 if (WARN_ON(space_info->bytes_pinned > 0 ||
10030 space_info->bytes_reserved > 0 ||
10031 space_info->bytes_may_use > 0))
10032 dump_space_info(space_info, 0, 0);
10033 list_del(&space_info->list);
10034 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
10035 struct kobject *kobj;
10036 kobj = space_info->block_group_kobjs[i];
10037 space_info->block_group_kobjs[i] = NULL;
10038 if (kobj) {
10039 kobject_del(kobj);
10040 kobject_put(kobj);
10041 }
10042 }
10043 kobject_del(&space_info->kobj);
10044 kobject_put(&space_info->kobj);
10045 }
10046 return 0;
10047 }
10048
10049 static void __link_block_group(struct btrfs_space_info *space_info,
10050 struct btrfs_block_group_cache *cache)
10051 {
10052 int index = get_block_group_index(cache);
10053 bool first = false;
10054
10055 down_write(&space_info->groups_sem);
10056 if (list_empty(&space_info->block_groups[index]))
10057 first = true;
10058 list_add_tail(&cache->list, &space_info->block_groups[index]);
10059 up_write(&space_info->groups_sem);
10060
10061 if (first) {
10062 struct raid_kobject *rkobj;
10063 int ret;
10064
10065 rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
10066 if (!rkobj)
10067 goto out_err;
10068 rkobj->raid_type = index;
10069 kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
10070 ret = kobject_add(&rkobj->kobj, &space_info->kobj,
10071 "%s", get_raid_name(index));
10072 if (ret) {
10073 kobject_put(&rkobj->kobj);
10074 goto out_err;
10075 }
10076 space_info->block_group_kobjs[index] = &rkobj->kobj;
10077 }
10078
10079 return;
10080 out_err:
10081 pr_warn("BTRFS: failed to add kobject for block cache. ignoring.\n");
10082 }
10083
10084 static struct btrfs_block_group_cache *
10085 btrfs_create_block_group_cache(struct btrfs_root *root, u64 start, u64 size)
10086 {
10087 struct btrfs_block_group_cache *cache;
10088
10089 cache = kzalloc(sizeof(*cache), GFP_NOFS);
10090 if (!cache)
10091 return NULL;
10092
10093 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
10094 GFP_NOFS);
10095 if (!cache->free_space_ctl) {
10096 kfree(cache);
10097 return NULL;
10098 }
10099
10100 cache->key.objectid = start;
10101 cache->key.offset = size;
10102 cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
10103
10104 cache->sectorsize = root->sectorsize;
10105 cache->fs_info = root->fs_info;
10106 cache->full_stripe_len = btrfs_full_stripe_len(root,
10107 &root->fs_info->mapping_tree,
10108 start);
10109 set_free_space_tree_thresholds(cache);
10110
10111 atomic_set(&cache->count, 1);
10112 spin_lock_init(&cache->lock);
10113 init_rwsem(&cache->data_rwsem);
10114 INIT_LIST_HEAD(&cache->list);
10115 INIT_LIST_HEAD(&cache->cluster_list);
10116 INIT_LIST_HEAD(&cache->bg_list);
10117 INIT_LIST_HEAD(&cache->ro_list);
10118 INIT_LIST_HEAD(&cache->dirty_list);
10119 INIT_LIST_HEAD(&cache->io_list);
10120 btrfs_init_free_space_ctl(cache);
10121 atomic_set(&cache->trimming, 0);
10122 mutex_init(&cache->free_space_lock);
10123
10124 return cache;
10125 }
10126
10127 int btrfs_read_block_groups(struct btrfs_root *root)
10128 {
10129 struct btrfs_path *path;
10130 int ret;
10131 struct btrfs_block_group_cache *cache;
10132 struct btrfs_fs_info *info = root->fs_info;
10133 struct btrfs_space_info *space_info;
10134 struct btrfs_key key;
10135 struct btrfs_key found_key;
10136 struct extent_buffer *leaf;
10137 int need_clear = 0;
10138 u64 cache_gen;
10139
10140 root = info->extent_root;
10141 key.objectid = 0;
10142 key.offset = 0;
10143 key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
10144 path = btrfs_alloc_path();
10145 if (!path)
10146 return -ENOMEM;
10147 path->reada = READA_FORWARD;
10148
10149 cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
10150 if (btrfs_test_opt(root->fs_info, SPACE_CACHE) &&
10151 btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
10152 need_clear = 1;
10153 if (btrfs_test_opt(root->fs_info, CLEAR_CACHE))
10154 need_clear = 1;
10155
10156 while (1) {
10157 ret = find_first_block_group(root, path, &key);
10158 if (ret > 0)
10159 break;
10160 if (ret != 0)
10161 goto error;
10162
10163 leaf = path->nodes[0];
10164 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
10165
10166 cache = btrfs_create_block_group_cache(root, found_key.objectid,
10167 found_key.offset);
10168 if (!cache) {
10169 ret = -ENOMEM;
10170 goto error;
10171 }
10172
10173 if (need_clear) {
10174 /*
10175 * When we mount with old space cache, we need to
10176 * set BTRFS_DC_CLEAR and set dirty flag.
10177 *
10178 * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
10179 * truncate the old free space cache inode and
10180 * setup a new one.
10181 * b) Setting 'dirty flag' makes sure that we flush
10182 * the new space cache info onto disk.
10183 */
10184 if (btrfs_test_opt(root->fs_info, SPACE_CACHE))
10185 cache->disk_cache_state = BTRFS_DC_CLEAR;
10186 }
10187
10188 read_extent_buffer(leaf, &cache->item,
10189 btrfs_item_ptr_offset(leaf, path->slots[0]),
10190 sizeof(cache->item));
10191 cache->flags = btrfs_block_group_flags(&cache->item);
10192
10193 key.objectid = found_key.objectid + found_key.offset;
10194 btrfs_release_path(path);
10195
10196 /*
10197 * We need to exclude the super stripes now so that the space
10198 * info has super bytes accounted for, otherwise we'll think
10199 * we have more space than we actually do.
10200 */
10201 ret = exclude_super_stripes(root, cache);
10202 if (ret) {
10203 /*
10204 * We may have excluded something, so call this just in
10205 * case.
10206 */
10207 free_excluded_extents(root, cache);
10208 btrfs_put_block_group(cache);
10209 goto error;
10210 }
10211
10212 /*
10213 * check for two cases, either we are full, and therefore
10214 * don't need to bother with the caching work since we won't
10215 * find any space, or we are empty, and we can just add all
10216 * the space in and be done with it. This saves us _alot_ of
10217 * time, particularly in the full case.
10218 */
10219 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
10220 cache->last_byte_to_unpin = (u64)-1;
10221 cache->cached = BTRFS_CACHE_FINISHED;
10222 free_excluded_extents(root, cache);
10223 } else if (btrfs_block_group_used(&cache->item) == 0) {
10224 cache->last_byte_to_unpin = (u64)-1;
10225 cache->cached = BTRFS_CACHE_FINISHED;
10226 add_new_free_space(cache, root->fs_info,
10227 found_key.objectid,
10228 found_key.objectid +
10229 found_key.offset);
10230 free_excluded_extents(root, cache);
10231 }
10232
10233 ret = btrfs_add_block_group_cache(root->fs_info, cache);
10234 if (ret) {
10235 btrfs_remove_free_space_cache(cache);
10236 btrfs_put_block_group(cache);
10237 goto error;
10238 }
10239
10240 trace_btrfs_add_block_group(root->fs_info, cache, 0);
10241 ret = update_space_info(info, cache->flags, found_key.offset,
10242 btrfs_block_group_used(&cache->item),
10243 cache->bytes_super, &space_info);
10244 if (ret) {
10245 btrfs_remove_free_space_cache(cache);
10246 spin_lock(&info->block_group_cache_lock);
10247 rb_erase(&cache->cache_node,
10248 &info->block_group_cache_tree);
10249 RB_CLEAR_NODE(&cache->cache_node);
10250 spin_unlock(&info->block_group_cache_lock);
10251 btrfs_put_block_group(cache);
10252 goto error;
10253 }
10254
10255 cache->space_info = space_info;
10256
10257 __link_block_group(space_info, cache);
10258
10259 set_avail_alloc_bits(root->fs_info, cache->flags);
10260 if (btrfs_chunk_readonly(root, cache->key.objectid)) {
10261 inc_block_group_ro(cache, 1);
10262 } else if (btrfs_block_group_used(&cache->item) == 0) {
10263 spin_lock(&info->unused_bgs_lock);
10264 /* Should always be true but just in case. */
10265 if (list_empty(&cache->bg_list)) {
10266 btrfs_get_block_group(cache);
10267 list_add_tail(&cache->bg_list,
10268 &info->unused_bgs);
10269 }
10270 spin_unlock(&info->unused_bgs_lock);
10271 }
10272 }
10273
10274 list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
10275 if (!(get_alloc_profile(root, space_info->flags) &
10276 (BTRFS_BLOCK_GROUP_RAID10 |
10277 BTRFS_BLOCK_GROUP_RAID1 |
10278 BTRFS_BLOCK_GROUP_RAID5 |
10279 BTRFS_BLOCK_GROUP_RAID6 |
10280 BTRFS_BLOCK_GROUP_DUP)))
10281 continue;
10282 /*
10283 * avoid allocating from un-mirrored block group if there are
10284 * mirrored block groups.
10285 */
10286 list_for_each_entry(cache,
10287 &space_info->block_groups[BTRFS_RAID_RAID0],
10288 list)
10289 inc_block_group_ro(cache, 1);
10290 list_for_each_entry(cache,
10291 &space_info->block_groups[BTRFS_RAID_SINGLE],
10292 list)
10293 inc_block_group_ro(cache, 1);
10294 }
10295
10296 init_global_block_rsv(info);
10297 ret = 0;
10298 error:
10299 btrfs_free_path(path);
10300 return ret;
10301 }
10302
10303 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
10304 struct btrfs_root *root)
10305 {
10306 struct btrfs_block_group_cache *block_group, *tmp;
10307 struct btrfs_root *extent_root = root->fs_info->extent_root;
10308 struct btrfs_block_group_item item;
10309 struct btrfs_key key;
10310 int ret = 0;
10311 bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
10312
10313 trans->can_flush_pending_bgs = false;
10314 list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
10315 if (ret)
10316 goto next;
10317
10318 spin_lock(&block_group->lock);
10319 memcpy(&item, &block_group->item, sizeof(item));
10320 memcpy(&key, &block_group->key, sizeof(key));
10321 spin_unlock(&block_group->lock);
10322
10323 ret = btrfs_insert_item(trans, extent_root, &key, &item,
10324 sizeof(item));
10325 if (ret)
10326 btrfs_abort_transaction(trans, ret);
10327 ret = btrfs_finish_chunk_alloc(trans, extent_root,
10328 key.objectid, key.offset);
10329 if (ret)
10330 btrfs_abort_transaction(trans, ret);
10331 add_block_group_free_space(trans, root->fs_info, block_group);
10332 /* already aborted the transaction if it failed. */
10333 next:
10334 list_del_init(&block_group->bg_list);
10335 }
10336 trans->can_flush_pending_bgs = can_flush_pending_bgs;
10337 }
10338
10339 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
10340 struct btrfs_root *root, u64 bytes_used,
10341 u64 type, u64 chunk_objectid, u64 chunk_offset,
10342 u64 size)
10343 {
10344 int ret;
10345 struct btrfs_root *extent_root;
10346 struct btrfs_block_group_cache *cache;
10347 extent_root = root->fs_info->extent_root;
10348
10349 btrfs_set_log_full_commit(root->fs_info, trans);
10350
10351 cache = btrfs_create_block_group_cache(root, chunk_offset, size);
10352 if (!cache)
10353 return -ENOMEM;
10354
10355 btrfs_set_block_group_used(&cache->item, bytes_used);
10356 btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
10357 btrfs_set_block_group_flags(&cache->item, type);
10358
10359 cache->flags = type;
10360 cache->last_byte_to_unpin = (u64)-1;
10361 cache->cached = BTRFS_CACHE_FINISHED;
10362 cache->needs_free_space = 1;
10363 ret = exclude_super_stripes(root, cache);
10364 if (ret) {
10365 /*
10366 * We may have excluded something, so call this just in
10367 * case.
10368 */
10369 free_excluded_extents(root, cache);
10370 btrfs_put_block_group(cache);
10371 return ret;
10372 }
10373
10374 add_new_free_space(cache, root->fs_info, chunk_offset,
10375 chunk_offset + size);
10376
10377 free_excluded_extents(root, cache);
10378
10379 #ifdef CONFIG_BTRFS_DEBUG
10380 if (btrfs_should_fragment_free_space(root, cache)) {
10381 u64 new_bytes_used = size - bytes_used;
10382
10383 bytes_used += new_bytes_used >> 1;
10384 fragment_free_space(root, cache);
10385 }
10386 #endif
10387 /*
10388 * Call to ensure the corresponding space_info object is created and
10389 * assigned to our block group, but don't update its counters just yet.
10390 * We want our bg to be added to the rbtree with its ->space_info set.
10391 */
10392 ret = update_space_info(root->fs_info, cache->flags, 0, 0, 0,
10393 &cache->space_info);
10394 if (ret) {
10395 btrfs_remove_free_space_cache(cache);
10396 btrfs_put_block_group(cache);
10397 return ret;
10398 }
10399
10400 ret = btrfs_add_block_group_cache(root->fs_info, cache);
10401 if (ret) {
10402 btrfs_remove_free_space_cache(cache);
10403 btrfs_put_block_group(cache);
10404 return ret;
10405 }
10406
10407 /*
10408 * Now that our block group has its ->space_info set and is inserted in
10409 * the rbtree, update the space info's counters.
10410 */
10411 trace_btrfs_add_block_group(root->fs_info, cache, 1);
10412 ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
10413 cache->bytes_super, &cache->space_info);
10414 if (ret) {
10415 btrfs_remove_free_space_cache(cache);
10416 spin_lock(&root->fs_info->block_group_cache_lock);
10417 rb_erase(&cache->cache_node,
10418 &root->fs_info->block_group_cache_tree);
10419 RB_CLEAR_NODE(&cache->cache_node);
10420 spin_unlock(&root->fs_info->block_group_cache_lock);
10421 btrfs_put_block_group(cache);
10422 return ret;
10423 }
10424 update_global_block_rsv(root->fs_info);
10425
10426 __link_block_group(cache->space_info, cache);
10427
10428 list_add_tail(&cache->bg_list, &trans->new_bgs);
10429
10430 set_avail_alloc_bits(extent_root->fs_info, type);
10431 return 0;
10432 }
10433
10434 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
10435 {
10436 u64 extra_flags = chunk_to_extended(flags) &
10437 BTRFS_EXTENDED_PROFILE_MASK;
10438
10439 write_seqlock(&fs_info->profiles_lock);
10440 if (flags & BTRFS_BLOCK_GROUP_DATA)
10441 fs_info->avail_data_alloc_bits &= ~extra_flags;
10442 if (flags & BTRFS_BLOCK_GROUP_METADATA)
10443 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
10444 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
10445 fs_info->avail_system_alloc_bits &= ~extra_flags;
10446 write_sequnlock(&fs_info->profiles_lock);
10447 }
10448
10449 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
10450 struct btrfs_root *root, u64 group_start,
10451 struct extent_map *em)
10452 {
10453 struct btrfs_path *path;
10454 struct btrfs_block_group_cache *block_group;
10455 struct btrfs_free_cluster *cluster;
10456 struct btrfs_root *tree_root = root->fs_info->tree_root;
10457 struct btrfs_key key;
10458 struct inode *inode;
10459 struct kobject *kobj = NULL;
10460 int ret;
10461 int index;
10462 int factor;
10463 struct btrfs_caching_control *caching_ctl = NULL;
10464 bool remove_em;
10465
10466 root = root->fs_info->extent_root;
10467
10468 block_group = btrfs_lookup_block_group(root->fs_info, group_start);
10469 BUG_ON(!block_group);
10470 BUG_ON(!block_group->ro);
10471
10472 /*
10473 * Free the reserved super bytes from this block group before
10474 * remove it.
10475 */
10476 free_excluded_extents(root, block_group);
10477
10478 memcpy(&key, &block_group->key, sizeof(key));
10479 index = get_block_group_index(block_group);
10480 if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
10481 BTRFS_BLOCK_GROUP_RAID1 |
10482 BTRFS_BLOCK_GROUP_RAID10))
10483 factor = 2;
10484 else
10485 factor = 1;
10486
10487 /* make sure this block group isn't part of an allocation cluster */
10488 cluster = &root->fs_info->data_alloc_cluster;
10489 spin_lock(&cluster->refill_lock);
10490 btrfs_return_cluster_to_free_space(block_group, cluster);
10491 spin_unlock(&cluster->refill_lock);
10492
10493 /*
10494 * make sure this block group isn't part of a metadata
10495 * allocation cluster
10496 */
10497 cluster = &root->fs_info->meta_alloc_cluster;
10498 spin_lock(&cluster->refill_lock);
10499 btrfs_return_cluster_to_free_space(block_group, cluster);
10500 spin_unlock(&cluster->refill_lock);
10501
10502 path = btrfs_alloc_path();
10503 if (!path) {
10504 ret = -ENOMEM;
10505 goto out;
10506 }
10507
10508 /*
10509 * get the inode first so any iput calls done for the io_list
10510 * aren't the final iput (no unlinks allowed now)
10511 */
10512 inode = lookup_free_space_inode(tree_root, block_group, path);
10513
10514 mutex_lock(&trans->transaction->cache_write_mutex);
10515 /*
10516 * make sure our free spache cache IO is done before remove the
10517 * free space inode
10518 */
10519 spin_lock(&trans->transaction->dirty_bgs_lock);
10520 if (!list_empty(&block_group->io_list)) {
10521 list_del_init(&block_group->io_list);
10522
10523 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
10524
10525 spin_unlock(&trans->transaction->dirty_bgs_lock);
10526 btrfs_wait_cache_io(root, trans, block_group,
10527 &block_group->io_ctl, path,
10528 block_group->key.objectid);
10529 btrfs_put_block_group(block_group);
10530 spin_lock(&trans->transaction->dirty_bgs_lock);
10531 }
10532
10533 if (!list_empty(&block_group->dirty_list)) {
10534 list_del_init(&block_group->dirty_list);
10535 btrfs_put_block_group(block_group);
10536 }
10537 spin_unlock(&trans->transaction->dirty_bgs_lock);
10538 mutex_unlock(&trans->transaction->cache_write_mutex);
10539
10540 if (!IS_ERR(inode)) {
10541 ret = btrfs_orphan_add(trans, inode);
10542 if (ret) {
10543 btrfs_add_delayed_iput(inode);
10544 goto out;
10545 }
10546 clear_nlink(inode);
10547 /* One for the block groups ref */
10548 spin_lock(&block_group->lock);
10549 if (block_group->iref) {
10550 block_group->iref = 0;
10551 block_group->inode = NULL;
10552 spin_unlock(&block_group->lock);
10553 iput(inode);
10554 } else {
10555 spin_unlock(&block_group->lock);
10556 }
10557 /* One for our lookup ref */
10558 btrfs_add_delayed_iput(inode);
10559 }
10560
10561 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
10562 key.offset = block_group->key.objectid;
10563 key.type = 0;
10564
10565 ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
10566 if (ret < 0)
10567 goto out;
10568 if (ret > 0)
10569 btrfs_release_path(path);
10570 if (ret == 0) {
10571 ret = btrfs_del_item(trans, tree_root, path);
10572 if (ret)
10573 goto out;
10574 btrfs_release_path(path);
10575 }
10576
10577 spin_lock(&root->fs_info->block_group_cache_lock);
10578 rb_erase(&block_group->cache_node,
10579 &root->fs_info->block_group_cache_tree);
10580 RB_CLEAR_NODE(&block_group->cache_node);
10581
10582 if (root->fs_info->first_logical_byte == block_group->key.objectid)
10583 root->fs_info->first_logical_byte = (u64)-1;
10584 spin_unlock(&root->fs_info->block_group_cache_lock);
10585
10586 down_write(&block_group->space_info->groups_sem);
10587 /*
10588 * we must use list_del_init so people can check to see if they
10589 * are still on the list after taking the semaphore
10590 */
10591 list_del_init(&block_group->list);
10592 if (list_empty(&block_group->space_info->block_groups[index])) {
10593 kobj = block_group->space_info->block_group_kobjs[index];
10594 block_group->space_info->block_group_kobjs[index] = NULL;
10595 clear_avail_alloc_bits(root->fs_info, block_group->flags);
10596 }
10597 up_write(&block_group->space_info->groups_sem);
10598 if (kobj) {
10599 kobject_del(kobj);
10600 kobject_put(kobj);
10601 }
10602
10603 if (block_group->has_caching_ctl)
10604 caching_ctl = get_caching_control(block_group);
10605 if (block_group->cached == BTRFS_CACHE_STARTED)
10606 wait_block_group_cache_done(block_group);
10607 if (block_group->has_caching_ctl) {
10608 down_write(&root->fs_info->commit_root_sem);
10609 if (!caching_ctl) {
10610 struct btrfs_caching_control *ctl;
10611
10612 list_for_each_entry(ctl,
10613 &root->fs_info->caching_block_groups, list)
10614 if (ctl->block_group == block_group) {
10615 caching_ctl = ctl;
10616 atomic_inc(&caching_ctl->count);
10617 break;
10618 }
10619 }
10620 if (caching_ctl)
10621 list_del_init(&caching_ctl->list);
10622 up_write(&root->fs_info->commit_root_sem);
10623 if (caching_ctl) {
10624 /* Once for the caching bgs list and once for us. */
10625 put_caching_control(caching_ctl);
10626 put_caching_control(caching_ctl);
10627 }
10628 }
10629
10630 spin_lock(&trans->transaction->dirty_bgs_lock);
10631 if (!list_empty(&block_group->dirty_list)) {
10632 WARN_ON(1);
10633 }
10634 if (!list_empty(&block_group->io_list)) {
10635 WARN_ON(1);
10636 }
10637 spin_unlock(&trans->transaction->dirty_bgs_lock);
10638 btrfs_remove_free_space_cache(block_group);
10639
10640 spin_lock(&block_group->space_info->lock);
10641 list_del_init(&block_group->ro_list);
10642
10643 if (btrfs_test_opt(root->fs_info, ENOSPC_DEBUG)) {
10644 WARN_ON(block_group->space_info->total_bytes
10645 < block_group->key.offset);
10646 WARN_ON(block_group->space_info->bytes_readonly
10647 < block_group->key.offset);
10648 WARN_ON(block_group->space_info->disk_total
10649 < block_group->key.offset * factor);
10650 }
10651 block_group->space_info->total_bytes -= block_group->key.offset;
10652 block_group->space_info->bytes_readonly -= block_group->key.offset;
10653 block_group->space_info->disk_total -= block_group->key.offset * factor;
10654
10655 spin_unlock(&block_group->space_info->lock);
10656
10657 memcpy(&key, &block_group->key, sizeof(key));
10658
10659 lock_chunks(root);
10660 if (!list_empty(&em->list)) {
10661 /* We're in the transaction->pending_chunks list. */
10662 free_extent_map(em);
10663 }
10664 spin_lock(&block_group->lock);
10665 block_group->removed = 1;
10666 /*
10667 * At this point trimming can't start on this block group, because we
10668 * removed the block group from the tree fs_info->block_group_cache_tree
10669 * so no one can't find it anymore and even if someone already got this
10670 * block group before we removed it from the rbtree, they have already
10671 * incremented block_group->trimming - if they didn't, they won't find
10672 * any free space entries because we already removed them all when we
10673 * called btrfs_remove_free_space_cache().
10674 *
10675 * And we must not remove the extent map from the fs_info->mapping_tree
10676 * to prevent the same logical address range and physical device space
10677 * ranges from being reused for a new block group. This is because our
10678 * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
10679 * completely transactionless, so while it is trimming a range the
10680 * currently running transaction might finish and a new one start,
10681 * allowing for new block groups to be created that can reuse the same
10682 * physical device locations unless we take this special care.
10683 *
10684 * There may also be an implicit trim operation if the file system
10685 * is mounted with -odiscard. The same protections must remain
10686 * in place until the extents have been discarded completely when
10687 * the transaction commit has completed.
10688 */
10689 remove_em = (atomic_read(&block_group->trimming) == 0);
10690 /*
10691 * Make sure a trimmer task always sees the em in the pinned_chunks list
10692 * if it sees block_group->removed == 1 (needs to lock block_group->lock
10693 * before checking block_group->removed).
10694 */
10695 if (!remove_em) {
10696 /*
10697 * Our em might be in trans->transaction->pending_chunks which
10698 * is protected by fs_info->chunk_mutex ([lock|unlock]_chunks),
10699 * and so is the fs_info->pinned_chunks list.
10700 *
10701 * So at this point we must be holding the chunk_mutex to avoid
10702 * any races with chunk allocation (more specifically at
10703 * volumes.c:contains_pending_extent()), to ensure it always
10704 * sees the em, either in the pending_chunks list or in the
10705 * pinned_chunks list.
10706 */
10707 list_move_tail(&em->list, &root->fs_info->pinned_chunks);
10708 }
10709 spin_unlock(&block_group->lock);
10710
10711 if (remove_em) {
10712 struct extent_map_tree *em_tree;
10713
10714 em_tree = &root->fs_info->mapping_tree.map_tree;
10715 write_lock(&em_tree->lock);
10716 /*
10717 * The em might be in the pending_chunks list, so make sure the
10718 * chunk mutex is locked, since remove_extent_mapping() will
10719 * delete us from that list.
10720 */
10721 remove_extent_mapping(em_tree, em);
10722 write_unlock(&em_tree->lock);
10723 /* once for the tree */
10724 free_extent_map(em);
10725 }
10726
10727 unlock_chunks(root);
10728
10729 ret = remove_block_group_free_space(trans, root->fs_info, block_group);
10730 if (ret)
10731 goto out;
10732
10733 btrfs_put_block_group(block_group);
10734 btrfs_put_block_group(block_group);
10735
10736 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
10737 if (ret > 0)
10738 ret = -EIO;
10739 if (ret < 0)
10740 goto out;
10741
10742 ret = btrfs_del_item(trans, root, path);
10743 out:
10744 btrfs_free_path(path);
10745 return ret;
10746 }
10747
10748 struct btrfs_trans_handle *
10749 btrfs_start_trans_remove_block_group(struct btrfs_fs_info *fs_info,
10750 const u64 chunk_offset)
10751 {
10752 struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree;
10753 struct extent_map *em;
10754 struct map_lookup *map;
10755 unsigned int num_items;
10756
10757 read_lock(&em_tree->lock);
10758 em = lookup_extent_mapping(em_tree, chunk_offset, 1);
10759 read_unlock(&em_tree->lock);
10760 ASSERT(em && em->start == chunk_offset);
10761
10762 /*
10763 * We need to reserve 3 + N units from the metadata space info in order
10764 * to remove a block group (done at btrfs_remove_chunk() and at
10765 * btrfs_remove_block_group()), which are used for:
10766 *
10767 * 1 unit for adding the free space inode's orphan (located in the tree
10768 * of tree roots).
10769 * 1 unit for deleting the block group item (located in the extent
10770 * tree).
10771 * 1 unit for deleting the free space item (located in tree of tree
10772 * roots).
10773 * N units for deleting N device extent items corresponding to each
10774 * stripe (located in the device tree).
10775 *
10776 * In order to remove a block group we also need to reserve units in the
10777 * system space info in order to update the chunk tree (update one or
10778 * more device items and remove one chunk item), but this is done at
10779 * btrfs_remove_chunk() through a call to check_system_chunk().
10780 */
10781 map = em->map_lookup;
10782 num_items = 3 + map->num_stripes;
10783 free_extent_map(em);
10784
10785 return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
10786 num_items, 1);
10787 }
10788
10789 /*
10790 * Process the unused_bgs list and remove any that don't have any allocated
10791 * space inside of them.
10792 */
10793 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
10794 {
10795 struct btrfs_block_group_cache *block_group;
10796 struct btrfs_space_info *space_info;
10797 struct btrfs_root *root = fs_info->extent_root;
10798 struct btrfs_trans_handle *trans;
10799 int ret = 0;
10800
10801 if (!fs_info->open)
10802 return;
10803
10804 spin_lock(&fs_info->unused_bgs_lock);
10805 while (!list_empty(&fs_info->unused_bgs)) {
10806 u64 start, end;
10807 int trimming;
10808
10809 block_group = list_first_entry(&fs_info->unused_bgs,
10810 struct btrfs_block_group_cache,
10811 bg_list);
10812 list_del_init(&block_group->bg_list);
10813
10814 space_info = block_group->space_info;
10815
10816 if (ret || btrfs_mixed_space_info(space_info)) {
10817 btrfs_put_block_group(block_group);
10818 continue;
10819 }
10820 spin_unlock(&fs_info->unused_bgs_lock);
10821
10822 mutex_lock(&fs_info->delete_unused_bgs_mutex);
10823
10824 /* Don't want to race with allocators so take the groups_sem */
10825 down_write(&space_info->groups_sem);
10826 spin_lock(&block_group->lock);
10827 if (block_group->reserved ||
10828 btrfs_block_group_used(&block_group->item) ||
10829 block_group->ro ||
10830 list_is_singular(&block_group->list)) {
10831 /*
10832 * We want to bail if we made new allocations or have
10833 * outstanding allocations in this block group. We do
10834 * the ro check in case balance is currently acting on
10835 * this block group.
10836 */
10837 spin_unlock(&block_group->lock);
10838 up_write(&space_info->groups_sem);
10839 goto next;
10840 }
10841 spin_unlock(&block_group->lock);
10842
10843 /* We don't want to force the issue, only flip if it's ok. */
10844 ret = inc_block_group_ro(block_group, 0);
10845 up_write(&space_info->groups_sem);
10846 if (ret < 0) {
10847 ret = 0;
10848 goto next;
10849 }
10850
10851 /*
10852 * Want to do this before we do anything else so we can recover
10853 * properly if we fail to join the transaction.
10854 */
10855 trans = btrfs_start_trans_remove_block_group(fs_info,
10856 block_group->key.objectid);
10857 if (IS_ERR(trans)) {
10858 btrfs_dec_block_group_ro(root, block_group);
10859 ret = PTR_ERR(trans);
10860 goto next;
10861 }
10862
10863 /*
10864 * We could have pending pinned extents for this block group,
10865 * just delete them, we don't care about them anymore.
10866 */
10867 start = block_group->key.objectid;
10868 end = start + block_group->key.offset - 1;
10869 /*
10870 * Hold the unused_bg_unpin_mutex lock to avoid racing with
10871 * btrfs_finish_extent_commit(). If we are at transaction N,
10872 * another task might be running finish_extent_commit() for the
10873 * previous transaction N - 1, and have seen a range belonging
10874 * to the block group in freed_extents[] before we were able to
10875 * clear the whole block group range from freed_extents[]. This
10876 * means that task can lookup for the block group after we
10877 * unpinned it from freed_extents[] and removed it, leading to
10878 * a BUG_ON() at btrfs_unpin_extent_range().
10879 */
10880 mutex_lock(&fs_info->unused_bg_unpin_mutex);
10881 ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
10882 EXTENT_DIRTY);
10883 if (ret) {
10884 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10885 btrfs_dec_block_group_ro(root, block_group);
10886 goto end_trans;
10887 }
10888 ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
10889 EXTENT_DIRTY);
10890 if (ret) {
10891 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10892 btrfs_dec_block_group_ro(root, block_group);
10893 goto end_trans;
10894 }
10895 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10896
10897 /* Reset pinned so btrfs_put_block_group doesn't complain */
10898 spin_lock(&space_info->lock);
10899 spin_lock(&block_group->lock);
10900
10901 space_info->bytes_pinned -= block_group->pinned;
10902 space_info->bytes_readonly += block_group->pinned;
10903 percpu_counter_add(&space_info->total_bytes_pinned,
10904 -block_group->pinned);
10905 block_group->pinned = 0;
10906
10907 spin_unlock(&block_group->lock);
10908 spin_unlock(&space_info->lock);
10909
10910 /* DISCARD can flip during remount */
10911 trimming = btrfs_test_opt(root->fs_info, DISCARD);
10912
10913 /* Implicit trim during transaction commit. */
10914 if (trimming)
10915 btrfs_get_block_group_trimming(block_group);
10916
10917 /*
10918 * Btrfs_remove_chunk will abort the transaction if things go
10919 * horribly wrong.
10920 */
10921 ret = btrfs_remove_chunk(trans, root,
10922 block_group->key.objectid);
10923
10924 if (ret) {
10925 if (trimming)
10926 btrfs_put_block_group_trimming(block_group);
10927 goto end_trans;
10928 }
10929
10930 /*
10931 * If we're not mounted with -odiscard, we can just forget
10932 * about this block group. Otherwise we'll need to wait
10933 * until transaction commit to do the actual discard.
10934 */
10935 if (trimming) {
10936 spin_lock(&fs_info->unused_bgs_lock);
10937 /*
10938 * A concurrent scrub might have added us to the list
10939 * fs_info->unused_bgs, so use a list_move operation
10940 * to add the block group to the deleted_bgs list.
10941 */
10942 list_move(&block_group->bg_list,
10943 &trans->transaction->deleted_bgs);
10944 spin_unlock(&fs_info->unused_bgs_lock);
10945 btrfs_get_block_group(block_group);
10946 }
10947 end_trans:
10948 btrfs_end_transaction(trans, root);
10949 next:
10950 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
10951 btrfs_put_block_group(block_group);
10952 spin_lock(&fs_info->unused_bgs_lock);
10953 }
10954 spin_unlock(&fs_info->unused_bgs_lock);
10955 }
10956
10957 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
10958 {
10959 struct btrfs_space_info *space_info;
10960 struct btrfs_super_block *disk_super;
10961 u64 features;
10962 u64 flags;
10963 int mixed = 0;
10964 int ret;
10965
10966 disk_super = fs_info->super_copy;
10967 if (!btrfs_super_root(disk_super))
10968 return -EINVAL;
10969
10970 features = btrfs_super_incompat_flags(disk_super);
10971 if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
10972 mixed = 1;
10973
10974 flags = BTRFS_BLOCK_GROUP_SYSTEM;
10975 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
10976 if (ret)
10977 goto out;
10978
10979 if (mixed) {
10980 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
10981 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
10982 } else {
10983 flags = BTRFS_BLOCK_GROUP_METADATA;
10984 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
10985 if (ret)
10986 goto out;
10987
10988 flags = BTRFS_BLOCK_GROUP_DATA;
10989 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
10990 }
10991 out:
10992 return ret;
10993 }
10994
10995 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
10996 {
10997 return unpin_extent_range(root, start, end, false);
10998 }
10999
11000 /*
11001 * It used to be that old block groups would be left around forever.
11002 * Iterating over them would be enough to trim unused space. Since we
11003 * now automatically remove them, we also need to iterate over unallocated
11004 * space.
11005 *
11006 * We don't want a transaction for this since the discard may take a
11007 * substantial amount of time. We don't require that a transaction be
11008 * running, but we do need to take a running transaction into account
11009 * to ensure that we're not discarding chunks that were released in
11010 * the current transaction.
11011 *
11012 * Holding the chunks lock will prevent other threads from allocating
11013 * or releasing chunks, but it won't prevent a running transaction
11014 * from committing and releasing the memory that the pending chunks
11015 * list head uses. For that, we need to take a reference to the
11016 * transaction.
11017 */
11018 static int btrfs_trim_free_extents(struct btrfs_device *device,
11019 u64 minlen, u64 *trimmed)
11020 {
11021 u64 start = 0, len = 0;
11022 int ret;
11023
11024 *trimmed = 0;
11025
11026 /* Not writeable = nothing to do. */
11027 if (!device->writeable)
11028 return 0;
11029
11030 /* No free space = nothing to do. */
11031 if (device->total_bytes <= device->bytes_used)
11032 return 0;
11033
11034 ret = 0;
11035
11036 while (1) {
11037 struct btrfs_fs_info *fs_info = device->dev_root->fs_info;
11038 struct btrfs_transaction *trans;
11039 u64 bytes;
11040
11041 ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
11042 if (ret)
11043 return ret;
11044
11045 down_read(&fs_info->commit_root_sem);
11046
11047 spin_lock(&fs_info->trans_lock);
11048 trans = fs_info->running_transaction;
11049 if (trans)
11050 atomic_inc(&trans->use_count);
11051 spin_unlock(&fs_info->trans_lock);
11052
11053 ret = find_free_dev_extent_start(trans, device, minlen, start,
11054 &start, &len);
11055 if (trans)
11056 btrfs_put_transaction(trans);
11057
11058 if (ret) {
11059 up_read(&fs_info->commit_root_sem);
11060 mutex_unlock(&fs_info->chunk_mutex);
11061 if (ret == -ENOSPC)
11062 ret = 0;
11063 break;
11064 }
11065
11066 ret = btrfs_issue_discard(device->bdev, start, len, &bytes);
11067 up_read(&fs_info->commit_root_sem);
11068 mutex_unlock(&fs_info->chunk_mutex);
11069
11070 if (ret)
11071 break;
11072
11073 start += len;
11074 *trimmed += bytes;
11075
11076 if (fatal_signal_pending(current)) {
11077 ret = -ERESTARTSYS;
11078 break;
11079 }
11080
11081 cond_resched();
11082 }
11083
11084 return ret;
11085 }
11086
11087 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
11088 {
11089 struct btrfs_fs_info *fs_info = root->fs_info;
11090 struct btrfs_block_group_cache *cache = NULL;
11091 struct btrfs_device *device;
11092 struct list_head *devices;
11093 u64 group_trimmed;
11094 u64 start;
11095 u64 end;
11096 u64 trimmed = 0;
11097 u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
11098 int ret = 0;
11099
11100 /*
11101 * try to trim all FS space, our block group may start from non-zero.
11102 */
11103 if (range->len == total_bytes)
11104 cache = btrfs_lookup_first_block_group(fs_info, range->start);
11105 else
11106 cache = btrfs_lookup_block_group(fs_info, range->start);
11107
11108 while (cache) {
11109 if (cache->key.objectid >= (range->start + range->len)) {
11110 btrfs_put_block_group(cache);
11111 break;
11112 }
11113
11114 start = max(range->start, cache->key.objectid);
11115 end = min(range->start + range->len,
11116 cache->key.objectid + cache->key.offset);
11117
11118 if (end - start >= range->minlen) {
11119 if (!block_group_cache_done(cache)) {
11120 ret = cache_block_group(cache, 0);
11121 if (ret) {
11122 btrfs_put_block_group(cache);
11123 break;
11124 }
11125 ret = wait_block_group_cache_done(cache);
11126 if (ret) {
11127 btrfs_put_block_group(cache);
11128 break;
11129 }
11130 }
11131 ret = btrfs_trim_block_group(cache,
11132 &group_trimmed,
11133 start,
11134 end,
11135 range->minlen);
11136
11137 trimmed += group_trimmed;
11138 if (ret) {
11139 btrfs_put_block_group(cache);
11140 break;
11141 }
11142 }
11143
11144 cache = next_block_group(fs_info->tree_root, cache);
11145 }
11146
11147 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
11148 devices = &root->fs_info->fs_devices->alloc_list;
11149 list_for_each_entry(device, devices, dev_alloc_list) {
11150 ret = btrfs_trim_free_extents(device, range->minlen,
11151 &group_trimmed);
11152 if (ret)
11153 break;
11154
11155 trimmed += group_trimmed;
11156 }
11157 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
11158
11159 range->len = trimmed;
11160 return ret;
11161 }
11162
11163 /*
11164 * btrfs_{start,end}_write_no_snapshoting() are similar to
11165 * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
11166 * data into the page cache through nocow before the subvolume is snapshoted,
11167 * but flush the data into disk after the snapshot creation, or to prevent
11168 * operations while snapshoting is ongoing and that cause the snapshot to be
11169 * inconsistent (writes followed by expanding truncates for example).
11170 */
11171 void btrfs_end_write_no_snapshoting(struct btrfs_root *root)
11172 {
11173 percpu_counter_dec(&root->subv_writers->counter);
11174 /*
11175 * Make sure counter is updated before we wake up waiters.
11176 */
11177 smp_mb();
11178 if (waitqueue_active(&root->subv_writers->wait))
11179 wake_up(&root->subv_writers->wait);
11180 }
11181
11182 int btrfs_start_write_no_snapshoting(struct btrfs_root *root)
11183 {
11184 if (atomic_read(&root->will_be_snapshoted))
11185 return 0;
11186
11187 percpu_counter_inc(&root->subv_writers->counter);
11188 /*
11189 * Make sure counter is updated before we check for snapshot creation.
11190 */
11191 smp_mb();
11192 if (atomic_read(&root->will_be_snapshoted)) {
11193 btrfs_end_write_no_snapshoting(root);
11194 return 0;
11195 }
11196 return 1;
11197 }
11198
11199 static int wait_snapshoting_atomic_t(atomic_t *a)
11200 {
11201 schedule();
11202 return 0;
11203 }
11204
11205 void btrfs_wait_for_snapshot_creation(struct btrfs_root *root)
11206 {
11207 while (true) {
11208 int ret;
11209
11210 ret = btrfs_start_write_no_snapshoting(root);
11211 if (ret)
11212 break;
11213 wait_on_atomic_t(&root->will_be_snapshoted,
11214 wait_snapshoting_atomic_t,
11215 TASK_UNINTERRUPTIBLE);
11216 }
11217 }
Linux with added FPC-III support