?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
scsi: fc: provide fc_bsg_to_rport() helper
[linux/fpc-iii.git] / fs / btrfs / extent-tree.c
blob4607af38c72e100e6728ff41d8198140dd722d93
1 /*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18 #include <linux/sched.h>
19 #include <linux/pagemap.h>
20 #include <linux/writeback.h>
21 #include <linux/blkdev.h>
22 #include <linux/sort.h>
23 #include <linux/rcupdate.h>
24 #include <linux/kthread.h>
25 #include <linux/slab.h>
26 #include <linux/ratelimit.h>
27 #include <linux/percpu_counter.h>
28 #include "hash.h"
29 #include "tree-log.h"
30 #include "disk-io.h"
31 #include "print-tree.h"
32 #include "volumes.h"
33 #include "raid56.h"
34 #include "locking.h"
35 #include "free-space-cache.h"
36 #include "free-space-tree.h"
37 #include "math.h"
38 #include "sysfs.h"
39 #include "qgroup.h"
40
41 #undef SCRAMBLE_DELAYED_REFS
42
43 /*
44 * control flags for do_chunk_alloc's force field
45 * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
46 * if we really need one.
47 *
48 * CHUNK_ALLOC_LIMITED means to only try and allocate one
49 * if we have very few chunks already allocated. This is
50 * used as part of the clustering code to help make sure
51 * we have a good pool of storage to cluster in, without
52 * filling the FS with empty chunks
53 *
54 * CHUNK_ALLOC_FORCE means it must try to allocate one
55 *
56 */
57 enum {
58 CHUNK_ALLOC_NO_FORCE = 0,
59 CHUNK_ALLOC_LIMITED = 1,
60 CHUNK_ALLOC_FORCE = 2,
61 };
62
63 static int update_block_group(struct btrfs_trans_handle *trans,
64 struct btrfs_root *root, u64 bytenr,
65 u64 num_bytes, int alloc);
66 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
67 struct btrfs_root *root,
68 struct btrfs_delayed_ref_node *node, u64 parent,
69 u64 root_objectid, u64 owner_objectid,
70 u64 owner_offset, int refs_to_drop,
71 struct btrfs_delayed_extent_op *extra_op);
72 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
73 struct extent_buffer *leaf,
74 struct btrfs_extent_item *ei);
75 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
76 struct btrfs_root *root,
77 u64 parent, u64 root_objectid,
78 u64 flags, u64 owner, u64 offset,
79 struct btrfs_key *ins, int ref_mod);
80 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
81 struct btrfs_root *root,
82 u64 parent, u64 root_objectid,
83 u64 flags, struct btrfs_disk_key *key,
84 int level, struct btrfs_key *ins);
85 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
86 struct btrfs_root *extent_root, u64 flags,
87 int force);
88 static int find_next_key(struct btrfs_path *path, int level,
89 struct btrfs_key *key);
90 static void dump_space_info(struct btrfs_fs_info *fs_info,
91 struct btrfs_space_info *info, u64 bytes,
92 int dump_block_groups);
93 static int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
94 u64 ram_bytes, u64 num_bytes, int delalloc);
95 static int btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
96 u64 num_bytes, int delalloc);
97 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
98 u64 num_bytes);
99 int btrfs_pin_extent(struct btrfs_root *root,
100 u64 bytenr, u64 num_bytes, int reserved);
101 static int __reserve_metadata_bytes(struct btrfs_root *root,
102 struct btrfs_space_info *space_info,
103 u64 orig_bytes,
104 enum btrfs_reserve_flush_enum flush);
105 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
106 struct btrfs_space_info *space_info,
107 u64 num_bytes);
108 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
109 struct btrfs_space_info *space_info,
110 u64 num_bytes);
111
112 static noinline int
113 block_group_cache_done(struct btrfs_block_group_cache *cache)
114 {
115 smp_mb();
116 return cache->cached == BTRFS_CACHE_FINISHED ||
117 cache->cached == BTRFS_CACHE_ERROR;
118 }
119
120 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
121 {
122 return (cache->flags & bits) == bits;
123 }
124
125 void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
126 {
127 atomic_inc(&cache->count);
128 }
129
130 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
131 {
132 if (atomic_dec_and_test(&cache->count)) {
133 WARN_ON(cache->pinned > 0);
134 WARN_ON(cache->reserved > 0);
135 kfree(cache->free_space_ctl);
136 kfree(cache);
137 }
138 }
139
140 /*
141 * this adds the block group to the fs_info rb tree for the block group
142 * cache
143 */
144 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
145 struct btrfs_block_group_cache *block_group)
146 {
147 struct rb_node **p;
148 struct rb_node *parent = NULL;
149 struct btrfs_block_group_cache *cache;
150
151 spin_lock(&info->block_group_cache_lock);
152 p = &info->block_group_cache_tree.rb_node;
153
154 while (*p) {
155 parent = *p;
156 cache = rb_entry(parent, struct btrfs_block_group_cache,
157 cache_node);
158 if (block_group->key.objectid < cache->key.objectid) {
159 p = &(*p)->rb_left;
160 } else if (block_group->key.objectid > cache->key.objectid) {
161 p = &(*p)->rb_right;
162 } else {
163 spin_unlock(&info->block_group_cache_lock);
164 return -EEXIST;
165 }
166 }
167
168 rb_link_node(&block_group->cache_node, parent, p);
169 rb_insert_color(&block_group->cache_node,
170 &info->block_group_cache_tree);
171
172 if (info->first_logical_byte > block_group->key.objectid)
173 info->first_logical_byte = block_group->key.objectid;
174
175 spin_unlock(&info->block_group_cache_lock);
176
177 return 0;
178 }
179
180 /*
181 * This will return the block group at or after bytenr if contains is 0, else
182 * it will return the block group that contains the bytenr
183 */
184 static struct btrfs_block_group_cache *
185 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
186 int contains)
187 {
188 struct btrfs_block_group_cache *cache, *ret = NULL;
189 struct rb_node *n;
190 u64 end, start;
191
192 spin_lock(&info->block_group_cache_lock);
193 n = info->block_group_cache_tree.rb_node;
194
195 while (n) {
196 cache = rb_entry(n, struct btrfs_block_group_cache,
197 cache_node);
198 end = cache->key.objectid + cache->key.offset - 1;
199 start = cache->key.objectid;
200
201 if (bytenr < start) {
202 if (!contains && (!ret || start < ret->key.objectid))
203 ret = cache;
204 n = n->rb_left;
205 } else if (bytenr > start) {
206 if (contains && bytenr <= end) {
207 ret = cache;
208 break;
209 }
210 n = n->rb_right;
211 } else {
212 ret = cache;
213 break;
214 }
215 }
216 if (ret) {
217 btrfs_get_block_group(ret);
218 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
219 info->first_logical_byte = ret->key.objectid;
220 }
221 spin_unlock(&info->block_group_cache_lock);
222
223 return ret;
224 }
225
226 static int add_excluded_extent(struct btrfs_root *root,
227 u64 start, u64 num_bytes)
228 {
229 u64 end = start + num_bytes - 1;
230 set_extent_bits(&root->fs_info->freed_extents[0],
231 start, end, EXTENT_UPTODATE);
232 set_extent_bits(&root->fs_info->freed_extents[1],
233 start, end, EXTENT_UPTODATE);
234 return 0;
235 }
236
237 static void free_excluded_extents(struct btrfs_root *root,
238 struct btrfs_block_group_cache *cache)
239 {
240 u64 start, end;
241
242 start = cache->key.objectid;
243 end = start + cache->key.offset - 1;
244
245 clear_extent_bits(&root->fs_info->freed_extents[0],
246 start, end, EXTENT_UPTODATE);
247 clear_extent_bits(&root->fs_info->freed_extents[1],
248 start, end, EXTENT_UPTODATE);
249 }
250
251 static int exclude_super_stripes(struct btrfs_root *root,
252 struct btrfs_block_group_cache *cache)
253 {
254 u64 bytenr;
255 u64 *logical;
256 int stripe_len;
257 int i, nr, ret;
258
259 if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
260 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
261 cache->bytes_super += stripe_len;
262 ret = add_excluded_extent(root, cache->key.objectid,
263 stripe_len);
264 if (ret)
265 return ret;
266 }
267
268 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
269 bytenr = btrfs_sb_offset(i);
270 ret = btrfs_rmap_block(root->fs_info, cache->key.objectid,
271 bytenr, 0, &logical, &nr, &stripe_len);
272 if (ret)
273 return ret;
274
275 while (nr--) {
276 u64 start, len;
277
278 if (logical[nr] > cache->key.objectid +
279 cache->key.offset)
280 continue;
281
282 if (logical[nr] + stripe_len <= cache->key.objectid)
283 continue;
284
285 start = logical[nr];
286 if (start < cache->key.objectid) {
287 start = cache->key.objectid;
288 len = (logical[nr] + stripe_len) - start;
289 } else {
290 len = min_t(u64, stripe_len,
291 cache->key.objectid +
292 cache->key.offset - start);
293 }
294
295 cache->bytes_super += len;
296 ret = add_excluded_extent(root, start, len);
297 if (ret) {
298 kfree(logical);
299 return ret;
300 }
301 }
302
303 kfree(logical);
304 }
305 return 0;
306 }
307
308 static struct btrfs_caching_control *
309 get_caching_control(struct btrfs_block_group_cache *cache)
310 {
311 struct btrfs_caching_control *ctl;
312
313 spin_lock(&cache->lock);
314 if (!cache->caching_ctl) {
315 spin_unlock(&cache->lock);
316 return NULL;
317 }
318
319 ctl = cache->caching_ctl;
320 atomic_inc(&ctl->count);
321 spin_unlock(&cache->lock);
322 return ctl;
323 }
324
325 static void put_caching_control(struct btrfs_caching_control *ctl)
326 {
327 if (atomic_dec_and_test(&ctl->count))
328 kfree(ctl);
329 }
330
331 #ifdef CONFIG_BTRFS_DEBUG
332 static void fragment_free_space(struct btrfs_root *root,
333 struct btrfs_block_group_cache *block_group)
334 {
335 u64 start = block_group->key.objectid;
336 u64 len = block_group->key.offset;
337 u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ?
338 root->nodesize : root->sectorsize;
339 u64 step = chunk << 1;
340
341 while (len > chunk) {
342 btrfs_remove_free_space(block_group, start, chunk);
343 start += step;
344 if (len < step)
345 len = 0;
346 else
347 len -= step;
348 }
349 }
350 #endif
351
352 /*
353 * this is only called by cache_block_group, since we could have freed extents
354 * we need to check the pinned_extents for any extents that can't be used yet
355 * since their free space will be released as soon as the transaction commits.
356 */
357 u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
358 struct btrfs_fs_info *info, u64 start, u64 end)
359 {
360 u64 extent_start, extent_end, size, total_added = 0;
361 int ret;
362
363 while (start < end) {
364 ret = find_first_extent_bit(info->pinned_extents, start,
365 &extent_start, &extent_end,
366 EXTENT_DIRTY | EXTENT_UPTODATE,
367 NULL);
368 if (ret)
369 break;
370
371 if (extent_start <= start) {
372 start = extent_end + 1;
373 } else if (extent_start > start && extent_start < end) {
374 size = extent_start - start;
375 total_added += size;
376 ret = btrfs_add_free_space(block_group, start,
377 size);
378 BUG_ON(ret); /* -ENOMEM or logic error */
379 start = extent_end + 1;
380 } else {
381 break;
382 }
383 }
384
385 if (start < end) {
386 size = end - start;
387 total_added += size;
388 ret = btrfs_add_free_space(block_group, start, size);
389 BUG_ON(ret); /* -ENOMEM or logic error */
390 }
391
392 return total_added;
393 }
394
395 static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl)
396 {
397 struct btrfs_block_group_cache *block_group;
398 struct btrfs_fs_info *fs_info;
399 struct btrfs_root *extent_root;
400 struct btrfs_path *path;
401 struct extent_buffer *leaf;
402 struct btrfs_key key;
403 u64 total_found = 0;
404 u64 last = 0;
405 u32 nritems;
406 int ret;
407 bool wakeup = true;
408
409 block_group = caching_ctl->block_group;
410 fs_info = block_group->fs_info;
411 extent_root = fs_info->extent_root;
412
413 path = btrfs_alloc_path();
414 if (!path)
415 return -ENOMEM;
416
417 last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
418
419 #ifdef CONFIG_BTRFS_DEBUG
420 /*
421 * If we're fragmenting we don't want to make anybody think we can
422 * allocate from this block group until we've had a chance to fragment
423 * the free space.
424 */
425 if (btrfs_should_fragment_free_space(extent_root, block_group))
426 wakeup = false;
427 #endif
428 /*
429 * We don't want to deadlock with somebody trying to allocate a new
430 * extent for the extent root while also trying to search the extent
431 * root to add free space. So we skip locking and search the commit
432 * root, since its read-only
433 */
434 path->skip_locking = 1;
435 path->search_commit_root = 1;
436 path->reada = READA_FORWARD;
437
438 key.objectid = last;
439 key.offset = 0;
440 key.type = BTRFS_EXTENT_ITEM_KEY;
441
442 next:
443 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
444 if (ret < 0)
445 goto out;
446
447 leaf = path->nodes[0];
448 nritems = btrfs_header_nritems(leaf);
449
450 while (1) {
451 if (btrfs_fs_closing(fs_info) > 1) {
452 last = (u64)-1;
453 break;
454 }
455
456 if (path->slots[0] < nritems) {
457 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
458 } else {
459 ret = find_next_key(path, 0, &key);
460 if (ret)
461 break;
462
463 if (need_resched() ||
464 rwsem_is_contended(&fs_info->commit_root_sem)) {
465 if (wakeup)
466 caching_ctl->progress = last;
467 btrfs_release_path(path);
468 up_read(&fs_info->commit_root_sem);
469 mutex_unlock(&caching_ctl->mutex);
470 cond_resched();
471 mutex_lock(&caching_ctl->mutex);
472 down_read(&fs_info->commit_root_sem);
473 goto next;
474 }
475
476 ret = btrfs_next_leaf(extent_root, path);
477 if (ret < 0)
478 goto out;
479 if (ret)
480 break;
481 leaf = path->nodes[0];
482 nritems = btrfs_header_nritems(leaf);
483 continue;
484 }
485
486 if (key.objectid < last) {
487 key.objectid = last;
488 key.offset = 0;
489 key.type = BTRFS_EXTENT_ITEM_KEY;
490
491 if (wakeup)
492 caching_ctl->progress = last;
493 btrfs_release_path(path);
494 goto next;
495 }
496
497 if (key.objectid < block_group->key.objectid) {
498 path->slots[0]++;
499 continue;
500 }
501
502 if (key.objectid >= block_group->key.objectid +
503 block_group->key.offset)
504 break;
505
506 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
507 key.type == BTRFS_METADATA_ITEM_KEY) {
508 total_found += add_new_free_space(block_group,
509 fs_info, last,
510 key.objectid);
511 if (key.type == BTRFS_METADATA_ITEM_KEY)
512 last = key.objectid +
513 fs_info->tree_root->nodesize;
514 else
515 last = key.objectid + key.offset;
516
517 if (total_found > CACHING_CTL_WAKE_UP) {
518 total_found = 0;
519 if (wakeup)
520 wake_up(&caching_ctl->wait);
521 }
522 }
523 path->slots[0]++;
524 }
525 ret = 0;
526
527 total_found += add_new_free_space(block_group, fs_info, last,
528 block_group->key.objectid +
529 block_group->key.offset);
530 caching_ctl->progress = (u64)-1;
531
532 out:
533 btrfs_free_path(path);
534 return ret;
535 }
536
537 static noinline void caching_thread(struct btrfs_work *work)
538 {
539 struct btrfs_block_group_cache *block_group;
540 struct btrfs_fs_info *fs_info;
541 struct btrfs_caching_control *caching_ctl;
542 struct btrfs_root *extent_root;
543 int ret;
544
545 caching_ctl = container_of(work, struct btrfs_caching_control, work);
546 block_group = caching_ctl->block_group;
547 fs_info = block_group->fs_info;
548 extent_root = fs_info->extent_root;
549
550 mutex_lock(&caching_ctl->mutex);
551 down_read(&fs_info->commit_root_sem);
552
553 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
554 ret = load_free_space_tree(caching_ctl);
555 else
556 ret = load_extent_tree_free(caching_ctl);
557
558 spin_lock(&block_group->lock);
559 block_group->caching_ctl = NULL;
560 block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED;
561 spin_unlock(&block_group->lock);
562
563 #ifdef CONFIG_BTRFS_DEBUG
564 if (btrfs_should_fragment_free_space(extent_root, block_group)) {
565 u64 bytes_used;
566
567 spin_lock(&block_group->space_info->lock);
568 spin_lock(&block_group->lock);
569 bytes_used = block_group->key.offset -
570 btrfs_block_group_used(&block_group->item);
571 block_group->space_info->bytes_used += bytes_used >> 1;
572 spin_unlock(&block_group->lock);
573 spin_unlock(&block_group->space_info->lock);
574 fragment_free_space(extent_root, block_group);
575 }
576 #endif
577
578 caching_ctl->progress = (u64)-1;
579
580 up_read(&fs_info->commit_root_sem);
581 free_excluded_extents(fs_info->extent_root, block_group);
582 mutex_unlock(&caching_ctl->mutex);
583
584 wake_up(&caching_ctl->wait);
585
586 put_caching_control(caching_ctl);
587 btrfs_put_block_group(block_group);
588 }
589
590 static int cache_block_group(struct btrfs_block_group_cache *cache,
591 int load_cache_only)
592 {
593 DEFINE_WAIT(wait);
594 struct btrfs_fs_info *fs_info = cache->fs_info;
595 struct btrfs_caching_control *caching_ctl;
596 int ret = 0;
597
598 caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
599 if (!caching_ctl)
600 return -ENOMEM;
601
602 INIT_LIST_HEAD(&caching_ctl->list);
603 mutex_init(&caching_ctl->mutex);
604 init_waitqueue_head(&caching_ctl->wait);
605 caching_ctl->block_group = cache;
606 caching_ctl->progress = cache->key.objectid;
607 atomic_set(&caching_ctl->count, 1);
608 btrfs_init_work(&caching_ctl->work, btrfs_cache_helper,
609 caching_thread, NULL, NULL);
610
611 spin_lock(&cache->lock);
612 /*
613 * This should be a rare occasion, but this could happen I think in the
614 * case where one thread starts to load the space cache info, and then
615 * some other thread starts a transaction commit which tries to do an
616 * allocation while the other thread is still loading the space cache
617 * info. The previous loop should have kept us from choosing this block
618 * group, but if we've moved to the state where we will wait on caching
619 * block groups we need to first check if we're doing a fast load here,
620 * so we can wait for it to finish, otherwise we could end up allocating
621 * from a block group who's cache gets evicted for one reason or
622 * another.
623 */
624 while (cache->cached == BTRFS_CACHE_FAST) {
625 struct btrfs_caching_control *ctl;
626
627 ctl = cache->caching_ctl;
628 atomic_inc(&ctl->count);
629 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
630 spin_unlock(&cache->lock);
631
632 schedule();
633
634 finish_wait(&ctl->wait, &wait);
635 put_caching_control(ctl);
636 spin_lock(&cache->lock);
637 }
638
639 if (cache->cached != BTRFS_CACHE_NO) {
640 spin_unlock(&cache->lock);
641 kfree(caching_ctl);
642 return 0;
643 }
644 WARN_ON(cache->caching_ctl);
645 cache->caching_ctl = caching_ctl;
646 cache->cached = BTRFS_CACHE_FAST;
647 spin_unlock(&cache->lock);
648
649 if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
650 mutex_lock(&caching_ctl->mutex);
651 ret = load_free_space_cache(fs_info, cache);
652
653 spin_lock(&cache->lock);
654 if (ret == 1) {
655 cache->caching_ctl = NULL;
656 cache->cached = BTRFS_CACHE_FINISHED;
657 cache->last_byte_to_unpin = (u64)-1;
658 caching_ctl->progress = (u64)-1;
659 } else {
660 if (load_cache_only) {
661 cache->caching_ctl = NULL;
662 cache->cached = BTRFS_CACHE_NO;
663 } else {
664 cache->cached = BTRFS_CACHE_STARTED;
665 cache->has_caching_ctl = 1;
666 }
667 }
668 spin_unlock(&cache->lock);
669 #ifdef CONFIG_BTRFS_DEBUG
670 if (ret == 1 &&
671 btrfs_should_fragment_free_space(fs_info->extent_root,
672 cache)) {
673 u64 bytes_used;
674
675 spin_lock(&cache->space_info->lock);
676 spin_lock(&cache->lock);
677 bytes_used = cache->key.offset -
678 btrfs_block_group_used(&cache->item);
679 cache->space_info->bytes_used += bytes_used >> 1;
680 spin_unlock(&cache->lock);
681 spin_unlock(&cache->space_info->lock);
682 fragment_free_space(fs_info->extent_root, cache);
683 }
684 #endif
685 mutex_unlock(&caching_ctl->mutex);
686
687 wake_up(&caching_ctl->wait);
688 if (ret == 1) {
689 put_caching_control(caching_ctl);
690 free_excluded_extents(fs_info->extent_root, cache);
691 return 0;
692 }
693 } else {
694 /*
695 * We're either using the free space tree or no caching at all.
696 * Set cached to the appropriate value and wakeup any waiters.
697 */
698 spin_lock(&cache->lock);
699 if (load_cache_only) {
700 cache->caching_ctl = NULL;
701 cache->cached = BTRFS_CACHE_NO;
702 } else {
703 cache->cached = BTRFS_CACHE_STARTED;
704 cache->has_caching_ctl = 1;
705 }
706 spin_unlock(&cache->lock);
707 wake_up(&caching_ctl->wait);
708 }
709
710 if (load_cache_only) {
711 put_caching_control(caching_ctl);
712 return 0;
713 }
714
715 down_write(&fs_info->commit_root_sem);
716 atomic_inc(&caching_ctl->count);
717 list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
718 up_write(&fs_info->commit_root_sem);
719
720 btrfs_get_block_group(cache);
721
722 btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
723
724 return ret;
725 }
726
727 /*
728 * return the block group that starts at or after bytenr
729 */
730 static struct btrfs_block_group_cache *
731 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
732 {
733 return block_group_cache_tree_search(info, bytenr, 0);
734 }
735
736 /*
737 * return the block group that contains the given bytenr
738 */
739 struct btrfs_block_group_cache *btrfs_lookup_block_group(
740 struct btrfs_fs_info *info,
741 u64 bytenr)
742 {
743 return block_group_cache_tree_search(info, bytenr, 1);
744 }
745
746 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
747 u64 flags)
748 {
749 struct list_head *head = &info->space_info;
750 struct btrfs_space_info *found;
751
752 flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
753
754 rcu_read_lock();
755 list_for_each_entry_rcu(found, head, list) {
756 if (found->flags & flags) {
757 rcu_read_unlock();
758 return found;
759 }
760 }
761 rcu_read_unlock();
762 return NULL;
763 }
764
765 /*
766 * after adding space to the filesystem, we need to clear the full flags
767 * on all the space infos.
768 */
769 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
770 {
771 struct list_head *head = &info->space_info;
772 struct btrfs_space_info *found;
773
774 rcu_read_lock();
775 list_for_each_entry_rcu(found, head, list)
776 found->full = 0;
777 rcu_read_unlock();
778 }
779
780 /* simple helper to search for an existing data extent at a given offset */
781 int btrfs_lookup_data_extent(struct btrfs_root *root, u64 start, u64 len)
782 {
783 int ret;
784 struct btrfs_key key;
785 struct btrfs_path *path;
786
787 path = btrfs_alloc_path();
788 if (!path)
789 return -ENOMEM;
790
791 key.objectid = start;
792 key.offset = len;
793 key.type = BTRFS_EXTENT_ITEM_KEY;
794 ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
795 0, 0);
796 btrfs_free_path(path);
797 return ret;
798 }
799
800 /*
801 * helper function to lookup reference count and flags of a tree block.
802 *
803 * the head node for delayed ref is used to store the sum of all the
804 * reference count modifications queued up in the rbtree. the head
805 * node may also store the extent flags to set. This way you can check
806 * to see what the reference count and extent flags would be if all of
807 * the delayed refs are not processed.
808 */
809 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
810 struct btrfs_root *root, u64 bytenr,
811 u64 offset, int metadata, u64 *refs, u64 *flags)
812 {
813 struct btrfs_delayed_ref_head *head;
814 struct btrfs_delayed_ref_root *delayed_refs;
815 struct btrfs_path *path;
816 struct btrfs_extent_item *ei;
817 struct extent_buffer *leaf;
818 struct btrfs_key key;
819 u32 item_size;
820 u64 num_refs;
821 u64 extent_flags;
822 int ret;
823
824 /*
825 * If we don't have skinny metadata, don't bother doing anything
826 * different
827 */
828 if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA)) {
829 offset = root->nodesize;
830 metadata = 0;
831 }
832
833 path = btrfs_alloc_path();
834 if (!path)
835 return -ENOMEM;
836
837 if (!trans) {
838 path->skip_locking = 1;
839 path->search_commit_root = 1;
840 }
841
842 search_again:
843 key.objectid = bytenr;
844 key.offset = offset;
845 if (metadata)
846 key.type = BTRFS_METADATA_ITEM_KEY;
847 else
848 key.type = BTRFS_EXTENT_ITEM_KEY;
849
850 ret = btrfs_search_slot(trans, root->fs_info->extent_root,
851 &key, path, 0, 0);
852 if (ret < 0)
853 goto out_free;
854
855 if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
856 if (path->slots[0]) {
857 path->slots[0]--;
858 btrfs_item_key_to_cpu(path->nodes[0], &key,
859 path->slots[0]);
860 if (key.objectid == bytenr &&
861 key.type == BTRFS_EXTENT_ITEM_KEY &&
862 key.offset == root->nodesize)
863 ret = 0;
864 }
865 }
866
867 if (ret == 0) {
868 leaf = path->nodes[0];
869 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
870 if (item_size >= sizeof(*ei)) {
871 ei = btrfs_item_ptr(leaf, path->slots[0],
872 struct btrfs_extent_item);
873 num_refs = btrfs_extent_refs(leaf, ei);
874 extent_flags = btrfs_extent_flags(leaf, ei);
875 } else {
876 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
877 struct btrfs_extent_item_v0 *ei0;
878 BUG_ON(item_size != sizeof(*ei0));
879 ei0 = btrfs_item_ptr(leaf, path->slots[0],
880 struct btrfs_extent_item_v0);
881 num_refs = btrfs_extent_refs_v0(leaf, ei0);
882 /* FIXME: this isn't correct for data */
883 extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
884 #else
885 BUG();
886 #endif
887 }
888 BUG_ON(num_refs == 0);
889 } else {
890 num_refs = 0;
891 extent_flags = 0;
892 ret = 0;
893 }
894
895 if (!trans)
896 goto out;
897
898 delayed_refs = &trans->transaction->delayed_refs;
899 spin_lock(&delayed_refs->lock);
900 head = btrfs_find_delayed_ref_head(trans, bytenr);
901 if (head) {
902 if (!mutex_trylock(&head->mutex)) {
903 atomic_inc(&head->node.refs);
904 spin_unlock(&delayed_refs->lock);
905
906 btrfs_release_path(path);
907
908 /*
909 * Mutex was contended, block until it's released and try
910 * again
911 */
912 mutex_lock(&head->mutex);
913 mutex_unlock(&head->mutex);
914 btrfs_put_delayed_ref(&head->node);
915 goto search_again;
916 }
917 spin_lock(&head->lock);
918 if (head->extent_op && head->extent_op->update_flags)
919 extent_flags |= head->extent_op->flags_to_set;
920 else
921 BUG_ON(num_refs == 0);
922
923 num_refs += head->node.ref_mod;
924 spin_unlock(&head->lock);
925 mutex_unlock(&head->mutex);
926 }
927 spin_unlock(&delayed_refs->lock);
928 out:
929 WARN_ON(num_refs == 0);
930 if (refs)
931 *refs = num_refs;
932 if (flags)
933 *flags = extent_flags;
934 out_free:
935 btrfs_free_path(path);
936 return ret;
937 }
938
939 /*
940 * Back reference rules. Back refs have three main goals:
941 *
942 * 1) differentiate between all holders of references to an extent so that
943 * when a reference is dropped we can make sure it was a valid reference
944 * before freeing the extent.
945 *
946 * 2) Provide enough information to quickly find the holders of an extent
947 * if we notice a given block is corrupted or bad.
948 *
949 * 3) Make it easy to migrate blocks for FS shrinking or storage pool
950 * maintenance. This is actually the same as #2, but with a slightly
951 * different use case.
952 *
953 * There are two kinds of back refs. The implicit back refs is optimized
954 * for pointers in non-shared tree blocks. For a given pointer in a block,
955 * back refs of this kind provide information about the block's owner tree
956 * and the pointer's key. These information allow us to find the block by
957 * b-tree searching. The full back refs is for pointers in tree blocks not
958 * referenced by their owner trees. The location of tree block is recorded
959 * in the back refs. Actually the full back refs is generic, and can be
960 * used in all cases the implicit back refs is used. The major shortcoming
961 * of the full back refs is its overhead. Every time a tree block gets
962 * COWed, we have to update back refs entry for all pointers in it.
963 *
964 * For a newly allocated tree block, we use implicit back refs for
965 * pointers in it. This means most tree related operations only involve
966 * implicit back refs. For a tree block created in old transaction, the
967 * only way to drop a reference to it is COW it. So we can detect the
968 * event that tree block loses its owner tree's reference and do the
969 * back refs conversion.
970 *
971 * When a tree block is COWed through a tree, there are four cases:
972 *
973 * The reference count of the block is one and the tree is the block's
974 * owner tree. Nothing to do in this case.
975 *
976 * The reference count of the block is one and the tree is not the
977 * block's owner tree. In this case, full back refs is used for pointers
978 * in the block. Remove these full back refs, add implicit back refs for
979 * every pointers in the new block.
980 *
981 * The reference count of the block is greater than one and the tree is
982 * the block's owner tree. In this case, implicit back refs is used for
983 * pointers in the block. Add full back refs for every pointers in the
984 * block, increase lower level extents' reference counts. The original
985 * implicit back refs are entailed to the new block.
986 *
987 * The reference count of the block is greater than one and the tree is
988 * not the block's owner tree. Add implicit back refs for every pointer in
989 * the new block, increase lower level extents' reference count.
990 *
991 * Back Reference Key composing:
992 *
993 * The key objectid corresponds to the first byte in the extent,
994 * The key type is used to differentiate between types of back refs.
995 * There are different meanings of the key offset for different types
996 * of back refs.
997 *
998 * File extents can be referenced by:
999 *
1000 * - multiple snapshots, subvolumes, or different generations in one subvol
1001 * - different files inside a single subvolume
1002 * - different offsets inside a file (bookend extents in file.c)
1003 *
1004 * The extent ref structure for the implicit back refs has fields for:
1005 *
1006 * - Objectid of the subvolume root
1007 * - objectid of the file holding the reference
1008 * - original offset in the file
1009 * - how many bookend extents
1010 *
1011 * The key offset for the implicit back refs is hash of the first
1012 * three fields.
1013 *
1014 * The extent ref structure for the full back refs has field for:
1015 *
1016 * - number of pointers in the tree leaf
1017 *
1018 * The key offset for the implicit back refs is the first byte of
1019 * the tree leaf
1020 *
1021 * When a file extent is allocated, The implicit back refs is used.
1022 * the fields are filled in:
1023 *
1024 * (root_key.objectid, inode objectid, offset in file, 1)
1025 *
1026 * When a file extent is removed file truncation, we find the
1027 * corresponding implicit back refs and check the following fields:
1028 *
1029 * (btrfs_header_owner(leaf), inode objectid, offset in file)
1030 *
1031 * Btree extents can be referenced by:
1032 *
1033 * - Different subvolumes
1034 *
1035 * Both the implicit back refs and the full back refs for tree blocks
1036 * only consist of key. The key offset for the implicit back refs is
1037 * objectid of block's owner tree. The key offset for the full back refs
1038 * is the first byte of parent block.
1039 *
1040 * When implicit back refs is used, information about the lowest key and
1041 * level of the tree block are required. These information are stored in
1042 * tree block info structure.
1043 */
1044
1045 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1046 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
1047 struct btrfs_root *root,
1048 struct btrfs_path *path,
1049 u64 owner, u32 extra_size)
1050 {
1051 struct btrfs_extent_item *item;
1052 struct btrfs_extent_item_v0 *ei0;
1053 struct btrfs_extent_ref_v0 *ref0;
1054 struct btrfs_tree_block_info *bi;
1055 struct extent_buffer *leaf;
1056 struct btrfs_key key;
1057 struct btrfs_key found_key;
1058 u32 new_size = sizeof(*item);
1059 u64 refs;
1060 int ret;
1061
1062 leaf = path->nodes[0];
1063 BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
1064
1065 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1066 ei0 = btrfs_item_ptr(leaf, path->slots[0],
1067 struct btrfs_extent_item_v0);
1068 refs = btrfs_extent_refs_v0(leaf, ei0);
1069
1070 if (owner == (u64)-1) {
1071 while (1) {
1072 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1073 ret = btrfs_next_leaf(root, path);
1074 if (ret < 0)
1075 return ret;
1076 BUG_ON(ret > 0); /* Corruption */
1077 leaf = path->nodes[0];
1078 }
1079 btrfs_item_key_to_cpu(leaf, &found_key,
1080 path->slots[0]);
1081 BUG_ON(key.objectid != found_key.objectid);
1082 if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
1083 path->slots[0]++;
1084 continue;
1085 }
1086 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1087 struct btrfs_extent_ref_v0);
1088 owner = btrfs_ref_objectid_v0(leaf, ref0);
1089 break;
1090 }
1091 }
1092 btrfs_release_path(path);
1093
1094 if (owner < BTRFS_FIRST_FREE_OBJECTID)
1095 new_size += sizeof(*bi);
1096
1097 new_size -= sizeof(*ei0);
1098 ret = btrfs_search_slot(trans, root, &key, path,
1099 new_size + extra_size, 1);
1100 if (ret < 0)
1101 return ret;
1102 BUG_ON(ret); /* Corruption */
1103
1104 btrfs_extend_item(root, path, new_size);
1105
1106 leaf = path->nodes[0];
1107 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1108 btrfs_set_extent_refs(leaf, item, refs);
1109 /* FIXME: get real generation */
1110 btrfs_set_extent_generation(leaf, item, 0);
1111 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1112 btrfs_set_extent_flags(leaf, item,
1113 BTRFS_EXTENT_FLAG_TREE_BLOCK |
1114 BTRFS_BLOCK_FLAG_FULL_BACKREF);
1115 bi = (struct btrfs_tree_block_info *)(item + 1);
1116 /* FIXME: get first key of the block */
1117 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1118 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1119 } else {
1120 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1121 }
1122 btrfs_mark_buffer_dirty(leaf);
1123 return 0;
1124 }
1125 #endif
1126
1127 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1128 {
1129 u32 high_crc = ~(u32)0;
1130 u32 low_crc = ~(u32)0;
1131 __le64 lenum;
1132
1133 lenum = cpu_to_le64(root_objectid);
1134 high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
1135 lenum = cpu_to_le64(owner);
1136 low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1137 lenum = cpu_to_le64(offset);
1138 low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1139
1140 return ((u64)high_crc << 31) ^ (u64)low_crc;
1141 }
1142
1143 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1144 struct btrfs_extent_data_ref *ref)
1145 {
1146 return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1147 btrfs_extent_data_ref_objectid(leaf, ref),
1148 btrfs_extent_data_ref_offset(leaf, ref));
1149 }
1150
1151 static int match_extent_data_ref(struct extent_buffer *leaf,
1152 struct btrfs_extent_data_ref *ref,
1153 u64 root_objectid, u64 owner, u64 offset)
1154 {
1155 if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1156 btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1157 btrfs_extent_data_ref_offset(leaf, ref) != offset)
1158 return 0;
1159 return 1;
1160 }
1161
1162 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1163 struct btrfs_root *root,
1164 struct btrfs_path *path,
1165 u64 bytenr, u64 parent,
1166 u64 root_objectid,
1167 u64 owner, u64 offset)
1168 {
1169 struct btrfs_key key;
1170 struct btrfs_extent_data_ref *ref;
1171 struct extent_buffer *leaf;
1172 u32 nritems;
1173 int ret;
1174 int recow;
1175 int err = -ENOENT;
1176
1177 key.objectid = bytenr;
1178 if (parent) {
1179 key.type = BTRFS_SHARED_DATA_REF_KEY;
1180 key.offset = parent;
1181 } else {
1182 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1183 key.offset = hash_extent_data_ref(root_objectid,
1184 owner, offset);
1185 }
1186 again:
1187 recow = 0;
1188 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1189 if (ret < 0) {
1190 err = ret;
1191 goto fail;
1192 }
1193
1194 if (parent) {
1195 if (!ret)
1196 return 0;
1197 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1198 key.type = BTRFS_EXTENT_REF_V0_KEY;
1199 btrfs_release_path(path);
1200 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1201 if (ret < 0) {
1202 err = ret;
1203 goto fail;
1204 }
1205 if (!ret)
1206 return 0;
1207 #endif
1208 goto fail;
1209 }
1210
1211 leaf = path->nodes[0];
1212 nritems = btrfs_header_nritems(leaf);
1213 while (1) {
1214 if (path->slots[0] >= nritems) {
1215 ret = btrfs_next_leaf(root, path);
1216 if (ret < 0)
1217 err = ret;
1218 if (ret)
1219 goto fail;
1220
1221 leaf = path->nodes[0];
1222 nritems = btrfs_header_nritems(leaf);
1223 recow = 1;
1224 }
1225
1226 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1227 if (key.objectid != bytenr ||
1228 key.type != BTRFS_EXTENT_DATA_REF_KEY)
1229 goto fail;
1230
1231 ref = btrfs_item_ptr(leaf, path->slots[0],
1232 struct btrfs_extent_data_ref);
1233
1234 if (match_extent_data_ref(leaf, ref, root_objectid,
1235 owner, offset)) {
1236 if (recow) {
1237 btrfs_release_path(path);
1238 goto again;
1239 }
1240 err = 0;
1241 break;
1242 }
1243 path->slots[0]++;
1244 }
1245 fail:
1246 return err;
1247 }
1248
1249 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1250 struct btrfs_root *root,
1251 struct btrfs_path *path,
1252 u64 bytenr, u64 parent,
1253 u64 root_objectid, u64 owner,
1254 u64 offset, int refs_to_add)
1255 {
1256 struct btrfs_key key;
1257 struct extent_buffer *leaf;
1258 u32 size;
1259 u32 num_refs;
1260 int ret;
1261
1262 key.objectid = bytenr;
1263 if (parent) {
1264 key.type = BTRFS_SHARED_DATA_REF_KEY;
1265 key.offset = parent;
1266 size = sizeof(struct btrfs_shared_data_ref);
1267 } else {
1268 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1269 key.offset = hash_extent_data_ref(root_objectid,
1270 owner, offset);
1271 size = sizeof(struct btrfs_extent_data_ref);
1272 }
1273
1274 ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1275 if (ret && ret != -EEXIST)
1276 goto fail;
1277
1278 leaf = path->nodes[0];
1279 if (parent) {
1280 struct btrfs_shared_data_ref *ref;
1281 ref = btrfs_item_ptr(leaf, path->slots[0],
1282 struct btrfs_shared_data_ref);
1283 if (ret == 0) {
1284 btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1285 } else {
1286 num_refs = btrfs_shared_data_ref_count(leaf, ref);
1287 num_refs += refs_to_add;
1288 btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1289 }
1290 } else {
1291 struct btrfs_extent_data_ref *ref;
1292 while (ret == -EEXIST) {
1293 ref = btrfs_item_ptr(leaf, path->slots[0],
1294 struct btrfs_extent_data_ref);
1295 if (match_extent_data_ref(leaf, ref, root_objectid,
1296 owner, offset))
1297 break;
1298 btrfs_release_path(path);
1299 key.offset++;
1300 ret = btrfs_insert_empty_item(trans, root, path, &key,
1301 size);
1302 if (ret && ret != -EEXIST)
1303 goto fail;
1304
1305 leaf = path->nodes[0];
1306 }
1307 ref = btrfs_item_ptr(leaf, path->slots[0],
1308 struct btrfs_extent_data_ref);
1309 if (ret == 0) {
1310 btrfs_set_extent_data_ref_root(leaf, ref,
1311 root_objectid);
1312 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1313 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1314 btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1315 } else {
1316 num_refs = btrfs_extent_data_ref_count(leaf, ref);
1317 num_refs += refs_to_add;
1318 btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1319 }
1320 }
1321 btrfs_mark_buffer_dirty(leaf);
1322 ret = 0;
1323 fail:
1324 btrfs_release_path(path);
1325 return ret;
1326 }
1327
1328 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1329 struct btrfs_root *root,
1330 struct btrfs_path *path,
1331 int refs_to_drop, int *last_ref)
1332 {
1333 struct btrfs_key key;
1334 struct btrfs_extent_data_ref *ref1 = NULL;
1335 struct btrfs_shared_data_ref *ref2 = NULL;
1336 struct extent_buffer *leaf;
1337 u32 num_refs = 0;
1338 int ret = 0;
1339
1340 leaf = path->nodes[0];
1341 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1342
1343 if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1344 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1345 struct btrfs_extent_data_ref);
1346 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1347 } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1348 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1349 struct btrfs_shared_data_ref);
1350 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1351 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1352 } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1353 struct btrfs_extent_ref_v0 *ref0;
1354 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1355 struct btrfs_extent_ref_v0);
1356 num_refs = btrfs_ref_count_v0(leaf, ref0);
1357 #endif
1358 } else {
1359 BUG();
1360 }
1361
1362 BUG_ON(num_refs < refs_to_drop);
1363 num_refs -= refs_to_drop;
1364
1365 if (num_refs == 0) {
1366 ret = btrfs_del_item(trans, root, path);
1367 *last_ref = 1;
1368 } else {
1369 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1370 btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1371 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1372 btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1373 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1374 else {
1375 struct btrfs_extent_ref_v0 *ref0;
1376 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1377 struct btrfs_extent_ref_v0);
1378 btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1379 }
1380 #endif
1381 btrfs_mark_buffer_dirty(leaf);
1382 }
1383 return ret;
1384 }
1385
1386 static noinline u32 extent_data_ref_count(struct btrfs_path *path,
1387 struct btrfs_extent_inline_ref *iref)
1388 {
1389 struct btrfs_key key;
1390 struct extent_buffer *leaf;
1391 struct btrfs_extent_data_ref *ref1;
1392 struct btrfs_shared_data_ref *ref2;
1393 u32 num_refs = 0;
1394
1395 leaf = path->nodes[0];
1396 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1397 if (iref) {
1398 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1399 BTRFS_EXTENT_DATA_REF_KEY) {
1400 ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1401 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1402 } else {
1403 ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1404 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1405 }
1406 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1407 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1408 struct btrfs_extent_data_ref);
1409 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1410 } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1411 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1412 struct btrfs_shared_data_ref);
1413 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1414 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1415 } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1416 struct btrfs_extent_ref_v0 *ref0;
1417 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1418 struct btrfs_extent_ref_v0);
1419 num_refs = btrfs_ref_count_v0(leaf, ref0);
1420 #endif
1421 } else {
1422 WARN_ON(1);
1423 }
1424 return num_refs;
1425 }
1426
1427 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1428 struct btrfs_root *root,
1429 struct btrfs_path *path,
1430 u64 bytenr, u64 parent,
1431 u64 root_objectid)
1432 {
1433 struct btrfs_key key;
1434 int ret;
1435
1436 key.objectid = bytenr;
1437 if (parent) {
1438 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1439 key.offset = parent;
1440 } else {
1441 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1442 key.offset = root_objectid;
1443 }
1444
1445 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1446 if (ret > 0)
1447 ret = -ENOENT;
1448 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1449 if (ret == -ENOENT && parent) {
1450 btrfs_release_path(path);
1451 key.type = BTRFS_EXTENT_REF_V0_KEY;
1452 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1453 if (ret > 0)
1454 ret = -ENOENT;
1455 }
1456 #endif
1457 return ret;
1458 }
1459
1460 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1461 struct btrfs_root *root,
1462 struct btrfs_path *path,
1463 u64 bytenr, u64 parent,
1464 u64 root_objectid)
1465 {
1466 struct btrfs_key key;
1467 int ret;
1468
1469 key.objectid = bytenr;
1470 if (parent) {
1471 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1472 key.offset = parent;
1473 } else {
1474 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1475 key.offset = root_objectid;
1476 }
1477
1478 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1479 btrfs_release_path(path);
1480 return ret;
1481 }
1482
1483 static inline int extent_ref_type(u64 parent, u64 owner)
1484 {
1485 int type;
1486 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1487 if (parent > 0)
1488 type = BTRFS_SHARED_BLOCK_REF_KEY;
1489 else
1490 type = BTRFS_TREE_BLOCK_REF_KEY;
1491 } else {
1492 if (parent > 0)
1493 type = BTRFS_SHARED_DATA_REF_KEY;
1494 else
1495 type = BTRFS_EXTENT_DATA_REF_KEY;
1496 }
1497 return type;
1498 }
1499
1500 static int find_next_key(struct btrfs_path *path, int level,
1501 struct btrfs_key *key)
1502
1503 {
1504 for (; level < BTRFS_MAX_LEVEL; level++) {
1505 if (!path->nodes[level])
1506 break;
1507 if (path->slots[level] + 1 >=
1508 btrfs_header_nritems(path->nodes[level]))
1509 continue;
1510 if (level == 0)
1511 btrfs_item_key_to_cpu(path->nodes[level], key,
1512 path->slots[level] + 1);
1513 else
1514 btrfs_node_key_to_cpu(path->nodes[level], key,
1515 path->slots[level] + 1);
1516 return 0;
1517 }
1518 return 1;
1519 }
1520
1521 /*
1522 * look for inline back ref. if back ref is found, *ref_ret is set
1523 * to the address of inline back ref, and 0 is returned.
1524 *
1525 * if back ref isn't found, *ref_ret is set to the address where it
1526 * should be inserted, and -ENOENT is returned.
1527 *
1528 * if insert is true and there are too many inline back refs, the path
1529 * points to the extent item, and -EAGAIN is returned.
1530 *
1531 * NOTE: inline back refs are ordered in the same way that back ref
1532 * items in the tree are ordered.
1533 */
1534 static noinline_for_stack
1535 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1536 struct btrfs_root *root,
1537 struct btrfs_path *path,
1538 struct btrfs_extent_inline_ref **ref_ret,
1539 u64 bytenr, u64 num_bytes,
1540 u64 parent, u64 root_objectid,
1541 u64 owner, u64 offset, int insert)
1542 {
1543 struct btrfs_key key;
1544 struct extent_buffer *leaf;
1545 struct btrfs_extent_item *ei;
1546 struct btrfs_extent_inline_ref *iref;
1547 u64 flags;
1548 u64 item_size;
1549 unsigned long ptr;
1550 unsigned long end;
1551 int extra_size;
1552 int type;
1553 int want;
1554 int ret;
1555 int err = 0;
1556 bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
1557 SKINNY_METADATA);
1558
1559 key.objectid = bytenr;
1560 key.type = BTRFS_EXTENT_ITEM_KEY;
1561 key.offset = num_bytes;
1562
1563 want = extent_ref_type(parent, owner);
1564 if (insert) {
1565 extra_size = btrfs_extent_inline_ref_size(want);
1566 path->keep_locks = 1;
1567 } else
1568 extra_size = -1;
1569
1570 /*
1571 * Owner is our parent level, so we can just add one to get the level
1572 * for the block we are interested in.
1573 */
1574 if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1575 key.type = BTRFS_METADATA_ITEM_KEY;
1576 key.offset = owner;
1577 }
1578
1579 again:
1580 ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1581 if (ret < 0) {
1582 err = ret;
1583 goto out;
1584 }
1585
1586 /*
1587 * We may be a newly converted file system which still has the old fat
1588 * extent entries for metadata, so try and see if we have one of those.
1589 */
1590 if (ret > 0 && skinny_metadata) {
1591 skinny_metadata = false;
1592 if (path->slots[0]) {
1593 path->slots[0]--;
1594 btrfs_item_key_to_cpu(path->nodes[0], &key,
1595 path->slots[0]);
1596 if (key.objectid == bytenr &&
1597 key.type == BTRFS_EXTENT_ITEM_KEY &&
1598 key.offset == num_bytes)
1599 ret = 0;
1600 }
1601 if (ret) {
1602 key.objectid = bytenr;
1603 key.type = BTRFS_EXTENT_ITEM_KEY;
1604 key.offset = num_bytes;
1605 btrfs_release_path(path);
1606 goto again;
1607 }
1608 }
1609
1610 if (ret && !insert) {
1611 err = -ENOENT;
1612 goto out;
1613 } else if (WARN_ON(ret)) {
1614 err = -EIO;
1615 goto out;
1616 }
1617
1618 leaf = path->nodes[0];
1619 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1620 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1621 if (item_size < sizeof(*ei)) {
1622 if (!insert) {
1623 err = -ENOENT;
1624 goto out;
1625 }
1626 ret = convert_extent_item_v0(trans, root, path, owner,
1627 extra_size);
1628 if (ret < 0) {
1629 err = ret;
1630 goto out;
1631 }
1632 leaf = path->nodes[0];
1633 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1634 }
1635 #endif
1636 BUG_ON(item_size < sizeof(*ei));
1637
1638 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1639 flags = btrfs_extent_flags(leaf, ei);
1640
1641 ptr = (unsigned long)(ei + 1);
1642 end = (unsigned long)ei + item_size;
1643
1644 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1645 ptr += sizeof(struct btrfs_tree_block_info);
1646 BUG_ON(ptr > end);
1647 }
1648
1649 err = -ENOENT;
1650 while (1) {
1651 if (ptr >= end) {
1652 WARN_ON(ptr > end);
1653 break;
1654 }
1655 iref = (struct btrfs_extent_inline_ref *)ptr;
1656 type = btrfs_extent_inline_ref_type(leaf, iref);
1657 if (want < type)
1658 break;
1659 if (want > type) {
1660 ptr += btrfs_extent_inline_ref_size(type);
1661 continue;
1662 }
1663
1664 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1665 struct btrfs_extent_data_ref *dref;
1666 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1667 if (match_extent_data_ref(leaf, dref, root_objectid,
1668 owner, offset)) {
1669 err = 0;
1670 break;
1671 }
1672 if (hash_extent_data_ref_item(leaf, dref) <
1673 hash_extent_data_ref(root_objectid, owner, offset))
1674 break;
1675 } else {
1676 u64 ref_offset;
1677 ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1678 if (parent > 0) {
1679 if (parent == ref_offset) {
1680 err = 0;
1681 break;
1682 }
1683 if (ref_offset < parent)
1684 break;
1685 } else {
1686 if (root_objectid == ref_offset) {
1687 err = 0;
1688 break;
1689 }
1690 if (ref_offset < root_objectid)
1691 break;
1692 }
1693 }
1694 ptr += btrfs_extent_inline_ref_size(type);
1695 }
1696 if (err == -ENOENT && insert) {
1697 if (item_size + extra_size >=
1698 BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1699 err = -EAGAIN;
1700 goto out;
1701 }
1702 /*
1703 * To add new inline back ref, we have to make sure
1704 * there is no corresponding back ref item.
1705 * For simplicity, we just do not add new inline back
1706 * ref if there is any kind of item for this block
1707 */
1708 if (find_next_key(path, 0, &key) == 0 &&
1709 key.objectid == bytenr &&
1710 key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1711 err = -EAGAIN;
1712 goto out;
1713 }
1714 }
1715 *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1716 out:
1717 if (insert) {
1718 path->keep_locks = 0;
1719 btrfs_unlock_up_safe(path, 1);
1720 }
1721 return err;
1722 }
1723
1724 /*
1725 * helper to add new inline back ref
1726 */
1727 static noinline_for_stack
1728 void setup_inline_extent_backref(struct btrfs_root *root,
1729 struct btrfs_path *path,
1730 struct btrfs_extent_inline_ref *iref,
1731 u64 parent, u64 root_objectid,
1732 u64 owner, u64 offset, int refs_to_add,
1733 struct btrfs_delayed_extent_op *extent_op)
1734 {
1735 struct extent_buffer *leaf;
1736 struct btrfs_extent_item *ei;
1737 unsigned long ptr;
1738 unsigned long end;
1739 unsigned long item_offset;
1740 u64 refs;
1741 int size;
1742 int type;
1743
1744 leaf = path->nodes[0];
1745 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1746 item_offset = (unsigned long)iref - (unsigned long)ei;
1747
1748 type = extent_ref_type(parent, owner);
1749 size = btrfs_extent_inline_ref_size(type);
1750
1751 btrfs_extend_item(root, path, size);
1752
1753 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1754 refs = btrfs_extent_refs(leaf, ei);
1755 refs += refs_to_add;
1756 btrfs_set_extent_refs(leaf, ei, refs);
1757 if (extent_op)
1758 __run_delayed_extent_op(extent_op, leaf, ei);
1759
1760 ptr = (unsigned long)ei + item_offset;
1761 end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1762 if (ptr < end - size)
1763 memmove_extent_buffer(leaf, ptr + size, ptr,
1764 end - size - ptr);
1765
1766 iref = (struct btrfs_extent_inline_ref *)ptr;
1767 btrfs_set_extent_inline_ref_type(leaf, iref, type);
1768 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1769 struct btrfs_extent_data_ref *dref;
1770 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1771 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1772 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1773 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1774 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1775 } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1776 struct btrfs_shared_data_ref *sref;
1777 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1778 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1779 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1780 } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1781 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1782 } else {
1783 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1784 }
1785 btrfs_mark_buffer_dirty(leaf);
1786 }
1787
1788 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1789 struct btrfs_root *root,
1790 struct btrfs_path *path,
1791 struct btrfs_extent_inline_ref **ref_ret,
1792 u64 bytenr, u64 num_bytes, u64 parent,
1793 u64 root_objectid, u64 owner, u64 offset)
1794 {
1795 int ret;
1796
1797 ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1798 bytenr, num_bytes, parent,
1799 root_objectid, owner, offset, 0);
1800 if (ret != -ENOENT)
1801 return ret;
1802
1803 btrfs_release_path(path);
1804 *ref_ret = NULL;
1805
1806 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1807 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1808 root_objectid);
1809 } else {
1810 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1811 root_objectid, owner, offset);
1812 }
1813 return ret;
1814 }
1815
1816 /*
1817 * helper to update/remove inline back ref
1818 */
1819 static noinline_for_stack
1820 void update_inline_extent_backref(struct btrfs_root *root,
1821 struct btrfs_path *path,
1822 struct btrfs_extent_inline_ref *iref,
1823 int refs_to_mod,
1824 struct btrfs_delayed_extent_op *extent_op,
1825 int *last_ref)
1826 {
1827 struct extent_buffer *leaf;
1828 struct btrfs_extent_item *ei;
1829 struct btrfs_extent_data_ref *dref = NULL;
1830 struct btrfs_shared_data_ref *sref = NULL;
1831 unsigned long ptr;
1832 unsigned long end;
1833 u32 item_size;
1834 int size;
1835 int type;
1836 u64 refs;
1837
1838 leaf = path->nodes[0];
1839 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1840 refs = btrfs_extent_refs(leaf, ei);
1841 WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1842 refs += refs_to_mod;
1843 btrfs_set_extent_refs(leaf, ei, refs);
1844 if (extent_op)
1845 __run_delayed_extent_op(extent_op, leaf, ei);
1846
1847 type = btrfs_extent_inline_ref_type(leaf, iref);
1848
1849 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1850 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1851 refs = btrfs_extent_data_ref_count(leaf, dref);
1852 } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1853 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1854 refs = btrfs_shared_data_ref_count(leaf, sref);
1855 } else {
1856 refs = 1;
1857 BUG_ON(refs_to_mod != -1);
1858 }
1859
1860 BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1861 refs += refs_to_mod;
1862
1863 if (refs > 0) {
1864 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1865 btrfs_set_extent_data_ref_count(leaf, dref, refs);
1866 else
1867 btrfs_set_shared_data_ref_count(leaf, sref, refs);
1868 } else {
1869 *last_ref = 1;
1870 size = btrfs_extent_inline_ref_size(type);
1871 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1872 ptr = (unsigned long)iref;
1873 end = (unsigned long)ei + item_size;
1874 if (ptr + size < end)
1875 memmove_extent_buffer(leaf, ptr, ptr + size,
1876 end - ptr - size);
1877 item_size -= size;
1878 btrfs_truncate_item(root, path, item_size, 1);
1879 }
1880 btrfs_mark_buffer_dirty(leaf);
1881 }
1882
1883 static noinline_for_stack
1884 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1885 struct btrfs_root *root,
1886 struct btrfs_path *path,
1887 u64 bytenr, u64 num_bytes, u64 parent,
1888 u64 root_objectid, u64 owner,
1889 u64 offset, int refs_to_add,
1890 struct btrfs_delayed_extent_op *extent_op)
1891 {
1892 struct btrfs_extent_inline_ref *iref;
1893 int ret;
1894
1895 ret = lookup_inline_extent_backref(trans, root, path, &iref,
1896 bytenr, num_bytes, parent,
1897 root_objectid, owner, offset, 1);
1898 if (ret == 0) {
1899 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1900 update_inline_extent_backref(root, path, iref,
1901 refs_to_add, extent_op, NULL);
1902 } else if (ret == -ENOENT) {
1903 setup_inline_extent_backref(root, path, iref, parent,
1904 root_objectid, owner, offset,
1905 refs_to_add, extent_op);
1906 ret = 0;
1907 }
1908 return ret;
1909 }
1910
1911 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1912 struct btrfs_root *root,
1913 struct btrfs_path *path,
1914 u64 bytenr, u64 parent, u64 root_objectid,
1915 u64 owner, u64 offset, int refs_to_add)
1916 {
1917 int ret;
1918 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1919 BUG_ON(refs_to_add != 1);
1920 ret = insert_tree_block_ref(trans, root, path, bytenr,
1921 parent, root_objectid);
1922 } else {
1923 ret = insert_extent_data_ref(trans, root, path, bytenr,
1924 parent, root_objectid,
1925 owner, offset, refs_to_add);
1926 }
1927 return ret;
1928 }
1929
1930 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1931 struct btrfs_root *root,
1932 struct btrfs_path *path,
1933 struct btrfs_extent_inline_ref *iref,
1934 int refs_to_drop, int is_data, int *last_ref)
1935 {
1936 int ret = 0;
1937
1938 BUG_ON(!is_data && refs_to_drop != 1);
1939 if (iref) {
1940 update_inline_extent_backref(root, path, iref,
1941 -refs_to_drop, NULL, last_ref);
1942 } else if (is_data) {
1943 ret = remove_extent_data_ref(trans, root, path, refs_to_drop,
1944 last_ref);
1945 } else {
1946 *last_ref = 1;
1947 ret = btrfs_del_item(trans, root, path);
1948 }
1949 return ret;
1950 }
1951
1952 #define in_range(b, first, len) ((b) >= (first) && (b) < (first) + (len))
1953 static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
1954 u64 *discarded_bytes)
1955 {
1956 int j, ret = 0;
1957 u64 bytes_left, end;
1958 u64 aligned_start = ALIGN(start, 1 << 9);
1959
1960 if (WARN_ON(start != aligned_start)) {
1961 len -= aligned_start - start;
1962 len = round_down(len, 1 << 9);
1963 start = aligned_start;
1964 }
1965
1966 *discarded_bytes = 0;
1967
1968 if (!len)
1969 return 0;
1970
1971 end = start + len;
1972 bytes_left = len;
1973
1974 /* Skip any superblocks on this device. */
1975 for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
1976 u64 sb_start = btrfs_sb_offset(j);
1977 u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
1978 u64 size = sb_start - start;
1979
1980 if (!in_range(sb_start, start, bytes_left) &&
1981 !in_range(sb_end, start, bytes_left) &&
1982 !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
1983 continue;
1984
1985 /*
1986 * Superblock spans beginning of range. Adjust start and
1987 * try again.
1988 */
1989 if (sb_start <= start) {
1990 start += sb_end - start;
1991 if (start > end) {
1992 bytes_left = 0;
1993 break;
1994 }
1995 bytes_left = end - start;
1996 continue;
1997 }
1998
1999 if (size) {
2000 ret = blkdev_issue_discard(bdev, start >> 9, size >> 9,
2001 GFP_NOFS, 0);
2002 if (!ret)
2003 *discarded_bytes += size;
2004 else if (ret != -EOPNOTSUPP)
2005 return ret;
2006 }
2007
2008 start = sb_end;
2009 if (start > end) {
2010 bytes_left = 0;
2011 break;
2012 }
2013 bytes_left = end - start;
2014 }
2015
2016 if (bytes_left) {
2017 ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9,
2018 GFP_NOFS, 0);
2019 if (!ret)
2020 *discarded_bytes += bytes_left;
2021 }
2022 return ret;
2023 }
2024
2025 int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
2026 u64 num_bytes, u64 *actual_bytes)
2027 {
2028 int ret;
2029 u64 discarded_bytes = 0;
2030 struct btrfs_bio *bbio = NULL;
2031
2032
2033 /*
2034 * Avoid races with device replace and make sure our bbio has devices
2035 * associated to its stripes that don't go away while we are discarding.
2036 */
2037 btrfs_bio_counter_inc_blocked(root->fs_info);
2038 /* Tell the block device(s) that the sectors can be discarded */
2039 ret = btrfs_map_block(root->fs_info, REQ_OP_DISCARD,
2040 bytenr, &num_bytes, &bbio, 0);
2041 /* Error condition is -ENOMEM */
2042 if (!ret) {
2043 struct btrfs_bio_stripe *stripe = bbio->stripes;
2044 int i;
2045
2046
2047 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
2048 u64 bytes;
2049 if (!stripe->dev->can_discard)
2050 continue;
2051
2052 ret = btrfs_issue_discard(stripe->dev->bdev,
2053 stripe->physical,
2054 stripe->length,
2055 &bytes);
2056 if (!ret)
2057 discarded_bytes += bytes;
2058 else if (ret != -EOPNOTSUPP)
2059 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
2060
2061 /*
2062 * Just in case we get back EOPNOTSUPP for some reason,
2063 * just ignore the return value so we don't screw up
2064 * people calling discard_extent.
2065 */
2066 ret = 0;
2067 }
2068 btrfs_put_bbio(bbio);
2069 }
2070 btrfs_bio_counter_dec(root->fs_info);
2071
2072 if (actual_bytes)
2073 *actual_bytes = discarded_bytes;
2074
2075
2076 if (ret == -EOPNOTSUPP)
2077 ret = 0;
2078 return ret;
2079 }
2080
2081 /* Can return -ENOMEM */
2082 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2083 struct btrfs_root *root,
2084 u64 bytenr, u64 num_bytes, u64 parent,
2085 u64 root_objectid, u64 owner, u64 offset)
2086 {
2087 int ret;
2088 struct btrfs_fs_info *fs_info = root->fs_info;
2089
2090 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
2091 root_objectid == BTRFS_TREE_LOG_OBJECTID);
2092
2093 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
2094 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
2095 num_bytes,
2096 parent, root_objectid, (int)owner,
2097 BTRFS_ADD_DELAYED_REF, NULL);
2098 } else {
2099 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
2100 num_bytes, parent, root_objectid,
2101 owner, offset, 0,
2102 BTRFS_ADD_DELAYED_REF, NULL);
2103 }
2104 return ret;
2105 }
2106
2107 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2108 struct btrfs_root *root,
2109 struct btrfs_delayed_ref_node *node,
2110 u64 parent, u64 root_objectid,
2111 u64 owner, u64 offset, int refs_to_add,
2112 struct btrfs_delayed_extent_op *extent_op)
2113 {
2114 struct btrfs_fs_info *fs_info = root->fs_info;
2115 struct btrfs_path *path;
2116 struct extent_buffer *leaf;
2117 struct btrfs_extent_item *item;
2118 struct btrfs_key key;
2119 u64 bytenr = node->bytenr;
2120 u64 num_bytes = node->num_bytes;
2121 u64 refs;
2122 int ret;
2123
2124 path = btrfs_alloc_path();
2125 if (!path)
2126 return -ENOMEM;
2127
2128 path->reada = READA_FORWARD;
2129 path->leave_spinning = 1;
2130 /* this will setup the path even if it fails to insert the back ref */
2131 ret = insert_inline_extent_backref(trans, fs_info->extent_root, path,
2132 bytenr, num_bytes, parent,
2133 root_objectid, owner, offset,
2134 refs_to_add, extent_op);
2135 if ((ret < 0 && ret != -EAGAIN) || !ret)
2136 goto out;
2137
2138 /*
2139 * Ok we had -EAGAIN which means we didn't have space to insert and
2140 * inline extent ref, so just update the reference count and add a
2141 * normal backref.
2142 */
2143 leaf = path->nodes[0];
2144 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2145 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2146 refs = btrfs_extent_refs(leaf, item);
2147 btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2148 if (extent_op)
2149 __run_delayed_extent_op(extent_op, leaf, item);
2150
2151 btrfs_mark_buffer_dirty(leaf);
2152 btrfs_release_path(path);
2153
2154 path->reada = READA_FORWARD;
2155 path->leave_spinning = 1;
2156 /* now insert the actual backref */
2157 ret = insert_extent_backref(trans, root->fs_info->extent_root,
2158 path, bytenr, parent, root_objectid,
2159 owner, offset, refs_to_add);
2160 if (ret)
2161 btrfs_abort_transaction(trans, ret);
2162 out:
2163 btrfs_free_path(path);
2164 return ret;
2165 }
2166
2167 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2168 struct btrfs_root *root,
2169 struct btrfs_delayed_ref_node *node,
2170 struct btrfs_delayed_extent_op *extent_op,
2171 int insert_reserved)
2172 {
2173 int ret = 0;
2174 struct btrfs_delayed_data_ref *ref;
2175 struct btrfs_key ins;
2176 u64 parent = 0;
2177 u64 ref_root = 0;
2178 u64 flags = 0;
2179
2180 ins.objectid = node->bytenr;
2181 ins.offset = node->num_bytes;
2182 ins.type = BTRFS_EXTENT_ITEM_KEY;
2183
2184 ref = btrfs_delayed_node_to_data_ref(node);
2185 trace_run_delayed_data_ref(root->fs_info, node, ref, node->action);
2186
2187 if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2188 parent = ref->parent;
2189 ref_root = ref->root;
2190
2191 if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2192 if (extent_op)
2193 flags |= extent_op->flags_to_set;
2194 ret = alloc_reserved_file_extent(trans, root,
2195 parent, ref_root, flags,
2196 ref->objectid, ref->offset,
2197 &ins, node->ref_mod);
2198 } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2199 ret = __btrfs_inc_extent_ref(trans, root, node, parent,
2200 ref_root, ref->objectid,
2201 ref->offset, node->ref_mod,
2202 extent_op);
2203 } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2204 ret = __btrfs_free_extent(trans, root, node, parent,
2205 ref_root, ref->objectid,
2206 ref->offset, node->ref_mod,
2207 extent_op);
2208 } else {
2209 BUG();
2210 }
2211 return ret;
2212 }
2213
2214 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2215 struct extent_buffer *leaf,
2216 struct btrfs_extent_item *ei)
2217 {
2218 u64 flags = btrfs_extent_flags(leaf, ei);
2219 if (extent_op->update_flags) {
2220 flags |= extent_op->flags_to_set;
2221 btrfs_set_extent_flags(leaf, ei, flags);
2222 }
2223
2224 if (extent_op->update_key) {
2225 struct btrfs_tree_block_info *bi;
2226 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2227 bi = (struct btrfs_tree_block_info *)(ei + 1);
2228 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2229 }
2230 }
2231
2232 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2233 struct btrfs_root *root,
2234 struct btrfs_delayed_ref_node *node,
2235 struct btrfs_delayed_extent_op *extent_op)
2236 {
2237 struct btrfs_key key;
2238 struct btrfs_path *path;
2239 struct btrfs_extent_item *ei;
2240 struct extent_buffer *leaf;
2241 u32 item_size;
2242 int ret;
2243 int err = 0;
2244 int metadata = !extent_op->is_data;
2245
2246 if (trans->aborted)
2247 return 0;
2248
2249 if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2250 metadata = 0;
2251
2252 path = btrfs_alloc_path();
2253 if (!path)
2254 return -ENOMEM;
2255
2256 key.objectid = node->bytenr;
2257
2258 if (metadata) {
2259 key.type = BTRFS_METADATA_ITEM_KEY;
2260 key.offset = extent_op->level;
2261 } else {
2262 key.type = BTRFS_EXTENT_ITEM_KEY;
2263 key.offset = node->num_bytes;
2264 }
2265
2266 again:
2267 path->reada = READA_FORWARD;
2268 path->leave_spinning = 1;
2269 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2270 path, 0, 1);
2271 if (ret < 0) {
2272 err = ret;
2273 goto out;
2274 }
2275 if (ret > 0) {
2276 if (metadata) {
2277 if (path->slots[0] > 0) {
2278 path->slots[0]--;
2279 btrfs_item_key_to_cpu(path->nodes[0], &key,
2280 path->slots[0]);
2281 if (key.objectid == node->bytenr &&
2282 key.type == BTRFS_EXTENT_ITEM_KEY &&
2283 key.offset == node->num_bytes)
2284 ret = 0;
2285 }
2286 if (ret > 0) {
2287 btrfs_release_path(path);
2288 metadata = 0;
2289
2290 key.objectid = node->bytenr;
2291 key.offset = node->num_bytes;
2292 key.type = BTRFS_EXTENT_ITEM_KEY;
2293 goto again;
2294 }
2295 } else {
2296 err = -EIO;
2297 goto out;
2298 }
2299 }
2300
2301 leaf = path->nodes[0];
2302 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2303 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2304 if (item_size < sizeof(*ei)) {
2305 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2306 path, (u64)-1, 0);
2307 if (ret < 0) {
2308 err = ret;
2309 goto out;
2310 }
2311 leaf = path->nodes[0];
2312 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2313 }
2314 #endif
2315 BUG_ON(item_size < sizeof(*ei));
2316 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2317 __run_delayed_extent_op(extent_op, leaf, ei);
2318
2319 btrfs_mark_buffer_dirty(leaf);
2320 out:
2321 btrfs_free_path(path);
2322 return err;
2323 }
2324
2325 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2326 struct btrfs_root *root,
2327 struct btrfs_delayed_ref_node *node,
2328 struct btrfs_delayed_extent_op *extent_op,
2329 int insert_reserved)
2330 {
2331 int ret = 0;
2332 struct btrfs_delayed_tree_ref *ref;
2333 struct btrfs_key ins;
2334 u64 parent = 0;
2335 u64 ref_root = 0;
2336 bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
2337 SKINNY_METADATA);
2338
2339 ref = btrfs_delayed_node_to_tree_ref(node);
2340 trace_run_delayed_tree_ref(root->fs_info, node, ref, node->action);
2341
2342 if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2343 parent = ref->parent;
2344 ref_root = ref->root;
2345
2346 ins.objectid = node->bytenr;
2347 if (skinny_metadata) {
2348 ins.offset = ref->level;
2349 ins.type = BTRFS_METADATA_ITEM_KEY;
2350 } else {
2351 ins.offset = node->num_bytes;
2352 ins.type = BTRFS_EXTENT_ITEM_KEY;
2353 }
2354
2355 if (node->ref_mod != 1) {
2356 btrfs_err(root->fs_info,
2357 "btree block(%llu) has %d references rather than 1: action %d ref_root %llu parent %llu",
2358 node->bytenr, node->ref_mod, node->action, ref_root,
2359 parent);
2360 return -EIO;
2361 }
2362 if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2363 BUG_ON(!extent_op || !extent_op->update_flags);
2364 ret = alloc_reserved_tree_block(trans, root,
2365 parent, ref_root,
2366 extent_op->flags_to_set,
2367 &extent_op->key,
2368 ref->level, &ins);
2369 } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2370 ret = __btrfs_inc_extent_ref(trans, root, node,
2371 parent, ref_root,
2372 ref->level, 0, 1,
2373 extent_op);
2374 } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2375 ret = __btrfs_free_extent(trans, root, node,
2376 parent, ref_root,
2377 ref->level, 0, 1, extent_op);
2378 } else {
2379 BUG();
2380 }
2381 return ret;
2382 }
2383
2384 /* helper function to actually process a single delayed ref entry */
2385 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2386 struct btrfs_root *root,
2387 struct btrfs_delayed_ref_node *node,
2388 struct btrfs_delayed_extent_op *extent_op,
2389 int insert_reserved)
2390 {
2391 int ret = 0;
2392
2393 if (trans->aborted) {
2394 if (insert_reserved)
2395 btrfs_pin_extent(root, node->bytenr,
2396 node->num_bytes, 1);
2397 return 0;
2398 }
2399
2400 if (btrfs_delayed_ref_is_head(node)) {
2401 struct btrfs_delayed_ref_head *head;
2402 /*
2403 * we've hit the end of the chain and we were supposed
2404 * to insert this extent into the tree. But, it got
2405 * deleted before we ever needed to insert it, so all
2406 * we have to do is clean up the accounting
2407 */
2408 BUG_ON(extent_op);
2409 head = btrfs_delayed_node_to_head(node);
2410 trace_run_delayed_ref_head(root->fs_info, node, head,
2411 node->action);
2412
2413 if (insert_reserved) {
2414 btrfs_pin_extent(root, node->bytenr,
2415 node->num_bytes, 1);
2416 if (head->is_data) {
2417 ret = btrfs_del_csums(trans, root,
2418 node->bytenr,
2419 node->num_bytes);
2420 }
2421 }
2422
2423 /* Also free its reserved qgroup space */
2424 btrfs_qgroup_free_delayed_ref(root->fs_info,
2425 head->qgroup_ref_root,
2426 head->qgroup_reserved);
2427 return ret;
2428 }
2429
2430 if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2431 node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2432 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2433 insert_reserved);
2434 else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2435 node->type == BTRFS_SHARED_DATA_REF_KEY)
2436 ret = run_delayed_data_ref(trans, root, node, extent_op,
2437 insert_reserved);
2438 else
2439 BUG();
2440 return ret;
2441 }
2442
2443 static inline struct btrfs_delayed_ref_node *
2444 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2445 {
2446 struct btrfs_delayed_ref_node *ref;
2447
2448 if (list_empty(&head->ref_list))
2449 return NULL;
2450
2451 /*
2452 * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
2453 * This is to prevent a ref count from going down to zero, which deletes
2454 * the extent item from the extent tree, when there still are references
2455 * to add, which would fail because they would not find the extent item.
2456 */
2457 list_for_each_entry(ref, &head->ref_list, list) {
2458 if (ref->action == BTRFS_ADD_DELAYED_REF)
2459 return ref;
2460 }
2461
2462 return list_entry(head->ref_list.next, struct btrfs_delayed_ref_node,
2463 list);
2464 }
2465
2466 /*
2467 * Returns 0 on success or if called with an already aborted transaction.
2468 * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2469 */
2470 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2471 struct btrfs_root *root,
2472 unsigned long nr)
2473 {
2474 struct btrfs_delayed_ref_root *delayed_refs;
2475 struct btrfs_delayed_ref_node *ref;
2476 struct btrfs_delayed_ref_head *locked_ref = NULL;
2477 struct btrfs_delayed_extent_op *extent_op;
2478 struct btrfs_fs_info *fs_info = root->fs_info;
2479 ktime_t start = ktime_get();
2480 int ret;
2481 unsigned long count = 0;
2482 unsigned long actual_count = 0;
2483 int must_insert_reserved = 0;
2484
2485 delayed_refs = &trans->transaction->delayed_refs;
2486 while (1) {
2487 if (!locked_ref) {
2488 if (count >= nr)
2489 break;
2490
2491 spin_lock(&delayed_refs->lock);
2492 locked_ref = btrfs_select_ref_head(trans);
2493 if (!locked_ref) {
2494 spin_unlock(&delayed_refs->lock);
2495 break;
2496 }
2497
2498 /* grab the lock that says we are going to process
2499 * all the refs for this head */
2500 ret = btrfs_delayed_ref_lock(trans, locked_ref);
2501 spin_unlock(&delayed_refs->lock);
2502 /*
2503 * we may have dropped the spin lock to get the head
2504 * mutex lock, and that might have given someone else
2505 * time to free the head. If that's true, it has been
2506 * removed from our list and we can move on.
2507 */
2508 if (ret == -EAGAIN) {
2509 locked_ref = NULL;
2510 count++;
2511 continue;
2512 }
2513 }
2514
2515 /*
2516 * We need to try and merge add/drops of the same ref since we
2517 * can run into issues with relocate dropping the implicit ref
2518 * and then it being added back again before the drop can
2519 * finish. If we merged anything we need to re-loop so we can
2520 * get a good ref.
2521 * Or we can get node references of the same type that weren't
2522 * merged when created due to bumps in the tree mod seq, and
2523 * we need to merge them to prevent adding an inline extent
2524 * backref before dropping it (triggering a BUG_ON at
2525 * insert_inline_extent_backref()).
2526 */
2527 spin_lock(&locked_ref->lock);
2528 btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
2529 locked_ref);
2530
2531 /*
2532 * locked_ref is the head node, so we have to go one
2533 * node back for any delayed ref updates
2534 */
2535 ref = select_delayed_ref(locked_ref);
2536
2537 if (ref && ref->seq &&
2538 btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2539 spin_unlock(&locked_ref->lock);
2540 btrfs_delayed_ref_unlock(locked_ref);
2541 spin_lock(&delayed_refs->lock);
2542 locked_ref->processing = 0;
2543 delayed_refs->num_heads_ready++;
2544 spin_unlock(&delayed_refs->lock);
2545 locked_ref = NULL;
2546 cond_resched();
2547 count++;
2548 continue;
2549 }
2550
2551 /*
2552 * record the must insert reserved flag before we
2553 * drop the spin lock.
2554 */
2555 must_insert_reserved = locked_ref->must_insert_reserved;
2556 locked_ref->must_insert_reserved = 0;
2557
2558 extent_op = locked_ref->extent_op;
2559 locked_ref->extent_op = NULL;
2560
2561 if (!ref) {
2562
2563
2564 /* All delayed refs have been processed, Go ahead
2565 * and send the head node to run_one_delayed_ref,
2566 * so that any accounting fixes can happen
2567 */
2568 ref = &locked_ref->node;
2569
2570 if (extent_op && must_insert_reserved) {
2571 btrfs_free_delayed_extent_op(extent_op);
2572 extent_op = NULL;
2573 }
2574
2575 if (extent_op) {
2576 spin_unlock(&locked_ref->lock);
2577 ret = run_delayed_extent_op(trans, root,
2578 ref, extent_op);
2579 btrfs_free_delayed_extent_op(extent_op);
2580
2581 if (ret) {
2582 /*
2583 * Need to reset must_insert_reserved if
2584 * there was an error so the abort stuff
2585 * can cleanup the reserved space
2586 * properly.
2587 */
2588 if (must_insert_reserved)
2589 locked_ref->must_insert_reserved = 1;
2590 locked_ref->processing = 0;
2591 btrfs_debug(fs_info,
2592 "run_delayed_extent_op returned %d",
2593 ret);
2594 btrfs_delayed_ref_unlock(locked_ref);
2595 return ret;
2596 }
2597 continue;
2598 }
2599
2600 /*
2601 * Need to drop our head ref lock and re-acquire the
2602 * delayed ref lock and then re-check to make sure
2603 * nobody got added.
2604 */
2605 spin_unlock(&locked_ref->lock);
2606 spin_lock(&delayed_refs->lock);
2607 spin_lock(&locked_ref->lock);
2608 if (!list_empty(&locked_ref->ref_list) ||
2609 locked_ref->extent_op) {
2610 spin_unlock(&locked_ref->lock);
2611 spin_unlock(&delayed_refs->lock);
2612 continue;
2613 }
2614 ref->in_tree = 0;
2615 delayed_refs->num_heads--;
2616 rb_erase(&locked_ref->href_node,
2617 &delayed_refs->href_root);
2618 spin_unlock(&delayed_refs->lock);
2619 } else {
2620 actual_count++;
2621 ref->in_tree = 0;
2622 list_del(&ref->list);
2623 }
2624 atomic_dec(&delayed_refs->num_entries);
2625
2626 if (!btrfs_delayed_ref_is_head(ref)) {
2627 /*
2628 * when we play the delayed ref, also correct the
2629 * ref_mod on head
2630 */
2631 switch (ref->action) {
2632 case BTRFS_ADD_DELAYED_REF:
2633 case BTRFS_ADD_DELAYED_EXTENT:
2634 locked_ref->node.ref_mod -= ref->ref_mod;
2635 break;
2636 case BTRFS_DROP_DELAYED_REF:
2637 locked_ref->node.ref_mod += ref->ref_mod;
2638 break;
2639 default:
2640 WARN_ON(1);
2641 }
2642 }
2643 spin_unlock(&locked_ref->lock);
2644
2645 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2646 must_insert_reserved);
2647
2648 btrfs_free_delayed_extent_op(extent_op);
2649 if (ret) {
2650 spin_lock(&delayed_refs->lock);
2651 locked_ref->processing = 0;
2652 delayed_refs->num_heads_ready++;
2653 spin_unlock(&delayed_refs->lock);
2654 btrfs_delayed_ref_unlock(locked_ref);
2655 btrfs_put_delayed_ref(ref);
2656 btrfs_debug(fs_info, "run_one_delayed_ref returned %d",
2657 ret);
2658 return ret;
2659 }
2660
2661 /*
2662 * If this node is a head, that means all the refs in this head
2663 * have been dealt with, and we will pick the next head to deal
2664 * with, so we must unlock the head and drop it from the cluster
2665 * list before we release it.
2666 */
2667 if (btrfs_delayed_ref_is_head(ref)) {
2668 if (locked_ref->is_data &&
2669 locked_ref->total_ref_mod < 0) {
2670 spin_lock(&delayed_refs->lock);
2671 delayed_refs->pending_csums -= ref->num_bytes;
2672 spin_unlock(&delayed_refs->lock);
2673 }
2674 btrfs_delayed_ref_unlock(locked_ref);
2675 locked_ref = NULL;
2676 }
2677 btrfs_put_delayed_ref(ref);
2678 count++;
2679 cond_resched();
2680 }
2681
2682 /*
2683 * We don't want to include ref heads since we can have empty ref heads
2684 * and those will drastically skew our runtime down since we just do
2685 * accounting, no actual extent tree updates.
2686 */
2687 if (actual_count > 0) {
2688 u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2689 u64 avg;
2690
2691 /*
2692 * We weigh the current average higher than our current runtime
2693 * to avoid large swings in the average.
2694 */
2695 spin_lock(&delayed_refs->lock);
2696 avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2697 fs_info->avg_delayed_ref_runtime = avg >> 2; /* div by 4 */
2698 spin_unlock(&delayed_refs->lock);
2699 }
2700 return 0;
2701 }
2702
2703 #ifdef SCRAMBLE_DELAYED_REFS
2704 /*
2705 * Normally delayed refs get processed in ascending bytenr order. This
2706 * correlates in most cases to the order added. To expose dependencies on this
2707 * order, we start to process the tree in the middle instead of the beginning
2708 */
2709 static u64 find_middle(struct rb_root *root)
2710 {
2711 struct rb_node *n = root->rb_node;
2712 struct btrfs_delayed_ref_node *entry;
2713 int alt = 1;
2714 u64 middle;
2715 u64 first = 0, last = 0;
2716
2717 n = rb_first(root);
2718 if (n) {
2719 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2720 first = entry->bytenr;
2721 }
2722 n = rb_last(root);
2723 if (n) {
2724 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2725 last = entry->bytenr;
2726 }
2727 n = root->rb_node;
2728
2729 while (n) {
2730 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2731 WARN_ON(!entry->in_tree);
2732
2733 middle = entry->bytenr;
2734
2735 if (alt)
2736 n = n->rb_left;
2737 else
2738 n = n->rb_right;
2739
2740 alt = 1 - alt;
2741 }
2742 return middle;
2743 }
2744 #endif
2745
2746 static inline u64 heads_to_leaves(struct btrfs_root *root, u64 heads)
2747 {
2748 u64 num_bytes;
2749
2750 num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2751 sizeof(struct btrfs_extent_inline_ref));
2752 if (!btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2753 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2754
2755 /*
2756 * We don't ever fill up leaves all the way so multiply by 2 just to be
2757 * closer to what we're really going to want to use.
2758 */
2759 return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(root));
2760 }
2761
2762 /*
2763 * Takes the number of bytes to be csumm'ed and figures out how many leaves it
2764 * would require to store the csums for that many bytes.
2765 */
2766 u64 btrfs_csum_bytes_to_leaves(struct btrfs_root *root, u64 csum_bytes)
2767 {
2768 u64 csum_size;
2769 u64 num_csums_per_leaf;
2770 u64 num_csums;
2771
2772 csum_size = BTRFS_MAX_ITEM_SIZE(root);
2773 num_csums_per_leaf = div64_u64(csum_size,
2774 (u64)btrfs_super_csum_size(root->fs_info->super_copy));
2775 num_csums = div64_u64(csum_bytes, root->sectorsize);
2776 num_csums += num_csums_per_leaf - 1;
2777 num_csums = div64_u64(num_csums, num_csums_per_leaf);
2778 return num_csums;
2779 }
2780
2781 int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans,
2782 struct btrfs_root *root)
2783 {
2784 struct btrfs_block_rsv *global_rsv;
2785 u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2786 u64 csum_bytes = trans->transaction->delayed_refs.pending_csums;
2787 u64 num_dirty_bgs = trans->transaction->num_dirty_bgs;
2788 u64 num_bytes, num_dirty_bgs_bytes;
2789 int ret = 0;
2790
2791 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
2792 num_heads = heads_to_leaves(root, num_heads);
2793 if (num_heads > 1)
2794 num_bytes += (num_heads - 1) * root->nodesize;
2795 num_bytes <<= 1;
2796 num_bytes += btrfs_csum_bytes_to_leaves(root, csum_bytes) * root->nodesize;
2797 num_dirty_bgs_bytes = btrfs_calc_trans_metadata_size(root,
2798 num_dirty_bgs);
2799 global_rsv = &root->fs_info->global_block_rsv;
2800
2801 /*
2802 * If we can't allocate any more chunks lets make sure we have _lots_ of
2803 * wiggle room since running delayed refs can create more delayed refs.
2804 */
2805 if (global_rsv->space_info->full) {
2806 num_dirty_bgs_bytes <<= 1;
2807 num_bytes <<= 1;
2808 }
2809
2810 spin_lock(&global_rsv->lock);
2811 if (global_rsv->reserved <= num_bytes + num_dirty_bgs_bytes)
2812 ret = 1;
2813 spin_unlock(&global_rsv->lock);
2814 return ret;
2815 }
2816
2817 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2818 struct btrfs_root *root)
2819 {
2820 struct btrfs_fs_info *fs_info = root->fs_info;
2821 u64 num_entries =
2822 atomic_read(&trans->transaction->delayed_refs.num_entries);
2823 u64 avg_runtime;
2824 u64 val;
2825
2826 smp_mb();
2827 avg_runtime = fs_info->avg_delayed_ref_runtime;
2828 val = num_entries * avg_runtime;
2829 if (num_entries * avg_runtime >= NSEC_PER_SEC)
2830 return 1;
2831 if (val >= NSEC_PER_SEC / 2)
2832 return 2;
2833
2834 return btrfs_check_space_for_delayed_refs(trans, root);
2835 }
2836
2837 struct async_delayed_refs {
2838 struct btrfs_root *root;
2839 u64 transid;
2840 int count;
2841 int error;
2842 int sync;
2843 struct completion wait;
2844 struct btrfs_work work;
2845 };
2846
2847 static void delayed_ref_async_start(struct btrfs_work *work)
2848 {
2849 struct async_delayed_refs *async;
2850 struct btrfs_trans_handle *trans;
2851 int ret;
2852
2853 async = container_of(work, struct async_delayed_refs, work);
2854
2855 /* if the commit is already started, we don't need to wait here */
2856 if (btrfs_transaction_blocked(async->root->fs_info))
2857 goto done;
2858
2859 trans = btrfs_join_transaction(async->root);
2860 if (IS_ERR(trans)) {
2861 async->error = PTR_ERR(trans);
2862 goto done;
2863 }
2864
2865 /*
2866 * trans->sync means that when we call end_transaction, we won't
2867 * wait on delayed refs
2868 */
2869 trans->sync = true;
2870
2871 /* Don't bother flushing if we got into a different transaction */
2872 if (trans->transid > async->transid)
2873 goto end;
2874
2875 ret = btrfs_run_delayed_refs(trans, async->root, async->count);
2876 if (ret)
2877 async->error = ret;
2878 end:
2879 ret = btrfs_end_transaction(trans, async->root);
2880 if (ret && !async->error)
2881 async->error = ret;
2882 done:
2883 if (async->sync)
2884 complete(&async->wait);
2885 else
2886 kfree(async);
2887 }
2888
2889 int btrfs_async_run_delayed_refs(struct btrfs_root *root,
2890 unsigned long count, u64 transid, int wait)
2891 {
2892 struct async_delayed_refs *async;
2893 int ret;
2894
2895 async = kmalloc(sizeof(*async), GFP_NOFS);
2896 if (!async)
2897 return -ENOMEM;
2898
2899 async->root = root->fs_info->tree_root;
2900 async->count = count;
2901 async->error = 0;
2902 async->transid = transid;
2903 if (wait)
2904 async->sync = 1;
2905 else
2906 async->sync = 0;
2907 init_completion(&async->wait);
2908
2909 btrfs_init_work(&async->work, btrfs_extent_refs_helper,
2910 delayed_ref_async_start, NULL, NULL);
2911
2912 btrfs_queue_work(root->fs_info->extent_workers, &async->work);
2913
2914 if (wait) {
2915 wait_for_completion(&async->wait);
2916 ret = async->error;
2917 kfree(async);
2918 return ret;
2919 }
2920 return 0;
2921 }
2922
2923 /*
2924 * this starts processing the delayed reference count updates and
2925 * extent insertions we have queued up so far. count can be
2926 * 0, which means to process everything in the tree at the start
2927 * of the run (but not newly added entries), or it can be some target
2928 * number you'd like to process.
2929 *
2930 * Returns 0 on success or if called with an aborted transaction
2931 * Returns <0 on error and aborts the transaction
2932 */
2933 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2934 struct btrfs_root *root, unsigned long count)
2935 {
2936 struct rb_node *node;
2937 struct btrfs_delayed_ref_root *delayed_refs;
2938 struct btrfs_delayed_ref_head *head;
2939 int ret;
2940 int run_all = count == (unsigned long)-1;
2941 bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
2942
2943 /* We'll clean this up in btrfs_cleanup_transaction */
2944 if (trans->aborted)
2945 return 0;
2946
2947 if (test_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &root->fs_info->flags))
2948 return 0;
2949
2950 if (root == root->fs_info->extent_root)
2951 root = root->fs_info->tree_root;
2952
2953 delayed_refs = &trans->transaction->delayed_refs;
2954 if (count == 0)
2955 count = atomic_read(&delayed_refs->num_entries) * 2;
2956
2957 again:
2958 #ifdef SCRAMBLE_DELAYED_REFS
2959 delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2960 #endif
2961 trans->can_flush_pending_bgs = false;
2962 ret = __btrfs_run_delayed_refs(trans, root, count);
2963 if (ret < 0) {
2964 btrfs_abort_transaction(trans, ret);
2965 return ret;
2966 }
2967
2968 if (run_all) {
2969 if (!list_empty(&trans->new_bgs))
2970 btrfs_create_pending_block_groups(trans, root);
2971
2972 spin_lock(&delayed_refs->lock);
2973 node = rb_first(&delayed_refs->href_root);
2974 if (!node) {
2975 spin_unlock(&delayed_refs->lock);
2976 goto out;
2977 }
2978
2979 while (node) {
2980 head = rb_entry(node, struct btrfs_delayed_ref_head,
2981 href_node);
2982 if (btrfs_delayed_ref_is_head(&head->node)) {
2983 struct btrfs_delayed_ref_node *ref;
2984
2985 ref = &head->node;
2986 atomic_inc(&ref->refs);
2987
2988 spin_unlock(&delayed_refs->lock);
2989 /*
2990 * Mutex was contended, block until it's
2991 * released and try again
2992 */
2993 mutex_lock(&head->mutex);
2994 mutex_unlock(&head->mutex);
2995
2996 btrfs_put_delayed_ref(ref);
2997 cond_resched();
2998 goto again;
2999 } else {
3000 WARN_ON(1);
3001 }
3002 node = rb_next(node);
3003 }
3004 spin_unlock(&delayed_refs->lock);
3005 cond_resched();
3006 goto again;
3007 }
3008 out:
3009 assert_qgroups_uptodate(trans);
3010 trans->can_flush_pending_bgs = can_flush_pending_bgs;
3011 return 0;
3012 }
3013
3014 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
3015 struct btrfs_root *root,
3016 u64 bytenr, u64 num_bytes, u64 flags,
3017 int level, int is_data)
3018 {
3019 struct btrfs_delayed_extent_op *extent_op;
3020 int ret;
3021
3022 extent_op = btrfs_alloc_delayed_extent_op();
3023 if (!extent_op)
3024 return -ENOMEM;
3025
3026 extent_op->flags_to_set = flags;
3027 extent_op->update_flags = true;
3028 extent_op->update_key = false;
3029 extent_op->is_data = is_data ? true : false;
3030 extent_op->level = level;
3031
3032 ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
3033 num_bytes, extent_op);
3034 if (ret)
3035 btrfs_free_delayed_extent_op(extent_op);
3036 return ret;
3037 }
3038
3039 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
3040 struct btrfs_root *root,
3041 struct btrfs_path *path,
3042 u64 objectid, u64 offset, u64 bytenr)
3043 {
3044 struct btrfs_delayed_ref_head *head;
3045 struct btrfs_delayed_ref_node *ref;
3046 struct btrfs_delayed_data_ref *data_ref;
3047 struct btrfs_delayed_ref_root *delayed_refs;
3048 int ret = 0;
3049
3050 delayed_refs = &trans->transaction->delayed_refs;
3051 spin_lock(&delayed_refs->lock);
3052 head = btrfs_find_delayed_ref_head(trans, bytenr);
3053 if (!head) {
3054 spin_unlock(&delayed_refs->lock);
3055 return 0;
3056 }
3057
3058 if (!mutex_trylock(&head->mutex)) {
3059 atomic_inc(&head->node.refs);
3060 spin_unlock(&delayed_refs->lock);
3061
3062 btrfs_release_path(path);
3063
3064 /*
3065 * Mutex was contended, block until it's released and let
3066 * caller try again
3067 */
3068 mutex_lock(&head->mutex);
3069 mutex_unlock(&head->mutex);
3070 btrfs_put_delayed_ref(&head->node);
3071 return -EAGAIN;
3072 }
3073 spin_unlock(&delayed_refs->lock);
3074
3075 spin_lock(&head->lock);
3076 list_for_each_entry(ref, &head->ref_list, list) {
3077 /* If it's a shared ref we know a cross reference exists */
3078 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
3079 ret = 1;
3080 break;
3081 }
3082
3083 data_ref = btrfs_delayed_node_to_data_ref(ref);
3084
3085 /*
3086 * If our ref doesn't match the one we're currently looking at
3087 * then we have a cross reference.
3088 */
3089 if (data_ref->root != root->root_key.objectid ||
3090 data_ref->objectid != objectid ||
3091 data_ref->offset != offset) {
3092 ret = 1;
3093 break;
3094 }
3095 }
3096 spin_unlock(&head->lock);
3097 mutex_unlock(&head->mutex);
3098 return ret;
3099 }
3100
3101 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
3102 struct btrfs_root *root,
3103 struct btrfs_path *path,
3104 u64 objectid, u64 offset, u64 bytenr)
3105 {
3106 struct btrfs_root *extent_root = root->fs_info->extent_root;
3107 struct extent_buffer *leaf;
3108 struct btrfs_extent_data_ref *ref;
3109 struct btrfs_extent_inline_ref *iref;
3110 struct btrfs_extent_item *ei;
3111 struct btrfs_key key;
3112 u32 item_size;
3113 int ret;
3114
3115 key.objectid = bytenr;
3116 key.offset = (u64)-1;
3117 key.type = BTRFS_EXTENT_ITEM_KEY;
3118
3119 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
3120 if (ret < 0)
3121 goto out;
3122 BUG_ON(ret == 0); /* Corruption */
3123
3124 ret = -ENOENT;
3125 if (path->slots[0] == 0)
3126 goto out;
3127
3128 path->slots[0]--;
3129 leaf = path->nodes[0];
3130 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3131
3132 if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
3133 goto out;
3134
3135 ret = 1;
3136 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
3137 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3138 if (item_size < sizeof(*ei)) {
3139 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3140 goto out;
3141 }
3142 #endif
3143 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
3144
3145 if (item_size != sizeof(*ei) +
3146 btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
3147 goto out;
3148
3149 if (btrfs_extent_generation(leaf, ei) <=
3150 btrfs_root_last_snapshot(&root->root_item))
3151 goto out;
3152
3153 iref = (struct btrfs_extent_inline_ref *)(ei + 1);
3154 if (btrfs_extent_inline_ref_type(leaf, iref) !=
3155 BTRFS_EXTENT_DATA_REF_KEY)
3156 goto out;
3157
3158 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
3159 if (btrfs_extent_refs(leaf, ei) !=
3160 btrfs_extent_data_ref_count(leaf, ref) ||
3161 btrfs_extent_data_ref_root(leaf, ref) !=
3162 root->root_key.objectid ||
3163 btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
3164 btrfs_extent_data_ref_offset(leaf, ref) != offset)
3165 goto out;
3166
3167 ret = 0;
3168 out:
3169 return ret;
3170 }
3171
3172 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
3173 struct btrfs_root *root,
3174 u64 objectid, u64 offset, u64 bytenr)
3175 {
3176 struct btrfs_path *path;
3177 int ret;
3178 int ret2;
3179
3180 path = btrfs_alloc_path();
3181 if (!path)
3182 return -ENOENT;
3183
3184 do {
3185 ret = check_committed_ref(trans, root, path, objectid,
3186 offset, bytenr);
3187 if (ret && ret != -ENOENT)
3188 goto out;
3189
3190 ret2 = check_delayed_ref(trans, root, path, objectid,
3191 offset, bytenr);
3192 } while (ret2 == -EAGAIN);
3193
3194 if (ret2 && ret2 != -ENOENT) {
3195 ret = ret2;
3196 goto out;
3197 }
3198
3199 if (ret != -ENOENT || ret2 != -ENOENT)
3200 ret = 0;
3201 out:
3202 btrfs_free_path(path);
3203 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3204 WARN_ON(ret > 0);
3205 return ret;
3206 }
3207
3208 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3209 struct btrfs_root *root,
3210 struct extent_buffer *buf,
3211 int full_backref, int inc)
3212 {
3213 u64 bytenr;
3214 u64 num_bytes;
3215 u64 parent;
3216 u64 ref_root;
3217 u32 nritems;
3218 struct btrfs_key key;
3219 struct btrfs_file_extent_item *fi;
3220 int i;
3221 int level;
3222 int ret = 0;
3223 int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
3224 u64, u64, u64, u64, u64, u64);
3225
3226
3227 if (btrfs_is_testing(root->fs_info))
3228 return 0;
3229
3230 ref_root = btrfs_header_owner(buf);
3231 nritems = btrfs_header_nritems(buf);
3232 level = btrfs_header_level(buf);
3233
3234 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
3235 return 0;
3236
3237 if (inc)
3238 process_func = btrfs_inc_extent_ref;
3239 else
3240 process_func = btrfs_free_extent;
3241
3242 if (full_backref)
3243 parent = buf->start;
3244 else
3245 parent = 0;
3246
3247 for (i = 0; i < nritems; i++) {
3248 if (level == 0) {
3249 btrfs_item_key_to_cpu(buf, &key, i);
3250 if (key.type != BTRFS_EXTENT_DATA_KEY)
3251 continue;
3252 fi = btrfs_item_ptr(buf, i,
3253 struct btrfs_file_extent_item);
3254 if (btrfs_file_extent_type(buf, fi) ==
3255 BTRFS_FILE_EXTENT_INLINE)
3256 continue;
3257 bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3258 if (bytenr == 0)
3259 continue;
3260
3261 num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3262 key.offset -= btrfs_file_extent_offset(buf, fi);
3263 ret = process_func(trans, root, bytenr, num_bytes,
3264 parent, ref_root, key.objectid,
3265 key.offset);
3266 if (ret)
3267 goto fail;
3268 } else {
3269 bytenr = btrfs_node_blockptr(buf, i);
3270 num_bytes = root->nodesize;
3271 ret = process_func(trans, root, bytenr, num_bytes,
3272 parent, ref_root, level - 1, 0);
3273 if (ret)
3274 goto fail;
3275 }
3276 }
3277 return 0;
3278 fail:
3279 return ret;
3280 }
3281
3282 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3283 struct extent_buffer *buf, int full_backref)
3284 {
3285 return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
3286 }
3287
3288 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3289 struct extent_buffer *buf, int full_backref)
3290 {
3291 return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
3292 }
3293
3294 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3295 struct btrfs_root *root,
3296 struct btrfs_path *path,
3297 struct btrfs_block_group_cache *cache)
3298 {
3299 int ret;
3300 struct btrfs_root *extent_root = root->fs_info->extent_root;
3301 unsigned long bi;
3302 struct extent_buffer *leaf;
3303
3304 ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3305 if (ret) {
3306 if (ret > 0)
3307 ret = -ENOENT;
3308 goto fail;
3309 }
3310
3311 leaf = path->nodes[0];
3312 bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3313 write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3314 btrfs_mark_buffer_dirty(leaf);
3315 fail:
3316 btrfs_release_path(path);
3317 return ret;
3318
3319 }
3320
3321 static struct btrfs_block_group_cache *
3322 next_block_group(struct btrfs_root *root,
3323 struct btrfs_block_group_cache *cache)
3324 {
3325 struct rb_node *node;
3326
3327 spin_lock(&root->fs_info->block_group_cache_lock);
3328
3329 /* If our block group was removed, we need a full search. */
3330 if (RB_EMPTY_NODE(&cache->cache_node)) {
3331 const u64 next_bytenr = cache->key.objectid + cache->key.offset;
3332
3333 spin_unlock(&root->fs_info->block_group_cache_lock);
3334 btrfs_put_block_group(cache);
3335 cache = btrfs_lookup_first_block_group(root->fs_info,
3336 next_bytenr);
3337 return cache;
3338 }
3339 node = rb_next(&cache->cache_node);
3340 btrfs_put_block_group(cache);
3341 if (node) {
3342 cache = rb_entry(node, struct btrfs_block_group_cache,
3343 cache_node);
3344 btrfs_get_block_group(cache);
3345 } else
3346 cache = NULL;
3347 spin_unlock(&root->fs_info->block_group_cache_lock);
3348 return cache;
3349 }
3350
3351 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3352 struct btrfs_trans_handle *trans,
3353 struct btrfs_path *path)
3354 {
3355 struct btrfs_root *root = block_group->fs_info->tree_root;
3356 struct inode *inode = NULL;
3357 u64 alloc_hint = 0;
3358 int dcs = BTRFS_DC_ERROR;
3359 u64 num_pages = 0;
3360 int retries = 0;
3361 int ret = 0;
3362
3363 /*
3364 * If this block group is smaller than 100 megs don't bother caching the
3365 * block group.
3366 */
3367 if (block_group->key.offset < (100 * SZ_1M)) {
3368 spin_lock(&block_group->lock);
3369 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3370 spin_unlock(&block_group->lock);
3371 return 0;
3372 }
3373
3374 if (trans->aborted)
3375 return 0;
3376 again:
3377 inode = lookup_free_space_inode(root, block_group, path);
3378 if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3379 ret = PTR_ERR(inode);
3380 btrfs_release_path(path);
3381 goto out;
3382 }
3383
3384 if (IS_ERR(inode)) {
3385 BUG_ON(retries);
3386 retries++;
3387
3388 if (block_group->ro)
3389 goto out_free;
3390
3391 ret = create_free_space_inode(root, trans, block_group, path);
3392 if (ret)
3393 goto out_free;
3394 goto again;
3395 }
3396
3397 /* We've already setup this transaction, go ahead and exit */
3398 if (block_group->cache_generation == trans->transid &&
3399 i_size_read(inode)) {
3400 dcs = BTRFS_DC_SETUP;
3401 goto out_put;
3402 }
3403
3404 /*
3405 * We want to set the generation to 0, that way if anything goes wrong
3406 * from here on out we know not to trust this cache when we load up next
3407 * time.
3408 */
3409 BTRFS_I(inode)->generation = 0;
3410 ret = btrfs_update_inode(trans, root, inode);
3411 if (ret) {
3412 /*
3413 * So theoretically we could recover from this, simply set the
3414 * super cache generation to 0 so we know to invalidate the
3415 * cache, but then we'd have to keep track of the block groups
3416 * that fail this way so we know we _have_ to reset this cache
3417 * before the next commit or risk reading stale cache. So to
3418 * limit our exposure to horrible edge cases lets just abort the
3419 * transaction, this only happens in really bad situations
3420 * anyway.
3421 */
3422 btrfs_abort_transaction(trans, ret);
3423 goto out_put;
3424 }
3425 WARN_ON(ret);
3426
3427 if (i_size_read(inode) > 0) {
3428 ret = btrfs_check_trunc_cache_free_space(root,
3429 &root->fs_info->global_block_rsv);
3430 if (ret)
3431 goto out_put;
3432
3433 ret = btrfs_truncate_free_space_cache(root, trans, NULL, inode);
3434 if (ret)
3435 goto out_put;
3436 }
3437
3438 spin_lock(&block_group->lock);
3439 if (block_group->cached != BTRFS_CACHE_FINISHED ||
3440 !btrfs_test_opt(root->fs_info, SPACE_CACHE)) {
3441 /*
3442 * don't bother trying to write stuff out _if_
3443 * a) we're not cached,
3444 * b) we're with nospace_cache mount option.
3445 */
3446 dcs = BTRFS_DC_WRITTEN;
3447 spin_unlock(&block_group->lock);
3448 goto out_put;
3449 }
3450 spin_unlock(&block_group->lock);
3451
3452 /*
3453 * We hit an ENOSPC when setting up the cache in this transaction, just
3454 * skip doing the setup, we've already cleared the cache so we're safe.
3455 */
3456 if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
3457 ret = -ENOSPC;
3458 goto out_put;
3459 }
3460
3461 /*
3462 * Try to preallocate enough space based on how big the block group is.
3463 * Keep in mind this has to include any pinned space which could end up
3464 * taking up quite a bit since it's not folded into the other space
3465 * cache.
3466 */
3467 num_pages = div_u64(block_group->key.offset, SZ_256M);
3468 if (!num_pages)
3469 num_pages = 1;
3470
3471 num_pages *= 16;
3472 num_pages *= PAGE_SIZE;
3473
3474 ret = btrfs_check_data_free_space(inode, 0, num_pages);
3475 if (ret)
3476 goto out_put;
3477
3478 ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3479 num_pages, num_pages,
3480 &alloc_hint);
3481 /*
3482 * Our cache requires contiguous chunks so that we don't modify a bunch
3483 * of metadata or split extents when writing the cache out, which means
3484 * we can enospc if we are heavily fragmented in addition to just normal
3485 * out of space conditions. So if we hit this just skip setting up any
3486 * other block groups for this transaction, maybe we'll unpin enough
3487 * space the next time around.
3488 */
3489 if (!ret)
3490 dcs = BTRFS_DC_SETUP;
3491 else if (ret == -ENOSPC)
3492 set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
3493
3494 out_put:
3495 iput(inode);
3496 out_free:
3497 btrfs_release_path(path);
3498 out:
3499 spin_lock(&block_group->lock);
3500 if (!ret && dcs == BTRFS_DC_SETUP)
3501 block_group->cache_generation = trans->transid;
3502 block_group->disk_cache_state = dcs;
3503 spin_unlock(&block_group->lock);
3504
3505 return ret;
3506 }
3507
3508 int btrfs_setup_space_cache(struct btrfs_trans_handle *trans,
3509 struct btrfs_root *root)
3510 {
3511 struct btrfs_block_group_cache *cache, *tmp;
3512 struct btrfs_transaction *cur_trans = trans->transaction;
3513 struct btrfs_path *path;
3514
3515 if (list_empty(&cur_trans->dirty_bgs) ||
3516 !btrfs_test_opt(root->fs_info, SPACE_CACHE))
3517 return 0;
3518
3519 path = btrfs_alloc_path();
3520 if (!path)
3521 return -ENOMEM;
3522
3523 /* Could add new block groups, use _safe just in case */
3524 list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
3525 dirty_list) {
3526 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3527 cache_save_setup(cache, trans, path);
3528 }
3529
3530 btrfs_free_path(path);
3531 return 0;
3532 }
3533
3534 /*
3535 * transaction commit does final block group cache writeback during a
3536 * critical section where nothing is allowed to change the FS. This is
3537 * required in order for the cache to actually match the block group,
3538 * but can introduce a lot of latency into the commit.
3539 *
3540 * So, btrfs_start_dirty_block_groups is here to kick off block group
3541 * cache IO. There's a chance we'll have to redo some of it if the
3542 * block group changes again during the commit, but it greatly reduces
3543 * the commit latency by getting rid of the easy block groups while
3544 * we're still allowing others to join the commit.
3545 */
3546 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans,
3547 struct btrfs_root *root)
3548 {
3549 struct btrfs_block_group_cache *cache;
3550 struct btrfs_transaction *cur_trans = trans->transaction;
3551 int ret = 0;
3552 int should_put;
3553 struct btrfs_path *path = NULL;
3554 LIST_HEAD(dirty);
3555 struct list_head *io = &cur_trans->io_bgs;
3556 int num_started = 0;
3557 int loops = 0;
3558
3559 spin_lock(&cur_trans->dirty_bgs_lock);
3560 if (list_empty(&cur_trans->dirty_bgs)) {
3561 spin_unlock(&cur_trans->dirty_bgs_lock);
3562 return 0;
3563 }
3564 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3565 spin_unlock(&cur_trans->dirty_bgs_lock);
3566
3567 again:
3568 /*
3569 * make sure all the block groups on our dirty list actually
3570 * exist
3571 */
3572 btrfs_create_pending_block_groups(trans, root);
3573
3574 if (!path) {
3575 path = btrfs_alloc_path();
3576 if (!path)
3577 return -ENOMEM;
3578 }
3579
3580 /*
3581 * cache_write_mutex is here only to save us from balance or automatic
3582 * removal of empty block groups deleting this block group while we are
3583 * writing out the cache
3584 */
3585 mutex_lock(&trans->transaction->cache_write_mutex);
3586 while (!list_empty(&dirty)) {
3587 cache = list_first_entry(&dirty,
3588 struct btrfs_block_group_cache,
3589 dirty_list);
3590 /*
3591 * this can happen if something re-dirties a block
3592 * group that is already under IO. Just wait for it to
3593 * finish and then do it all again
3594 */
3595 if (!list_empty(&cache->io_list)) {
3596 list_del_init(&cache->io_list);
3597 btrfs_wait_cache_io(root, trans, cache,
3598 &cache->io_ctl, path,
3599 cache->key.objectid);
3600 btrfs_put_block_group(cache);
3601 }
3602
3603
3604 /*
3605 * btrfs_wait_cache_io uses the cache->dirty_list to decide
3606 * if it should update the cache_state. Don't delete
3607 * until after we wait.
3608 *
3609 * Since we're not running in the commit critical section
3610 * we need the dirty_bgs_lock to protect from update_block_group
3611 */
3612 spin_lock(&cur_trans->dirty_bgs_lock);
3613 list_del_init(&cache->dirty_list);
3614 spin_unlock(&cur_trans->dirty_bgs_lock);
3615
3616 should_put = 1;
3617
3618 cache_save_setup(cache, trans, path);
3619
3620 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
3621 cache->io_ctl.inode = NULL;
3622 ret = btrfs_write_out_cache(root, trans, cache, path);
3623 if (ret == 0 && cache->io_ctl.inode) {
3624 num_started++;
3625 should_put = 0;
3626
3627 /*
3628 * the cache_write_mutex is protecting
3629 * the io_list
3630 */
3631 list_add_tail(&cache->io_list, io);
3632 } else {
3633 /*
3634 * if we failed to write the cache, the
3635 * generation will be bad and life goes on
3636 */
3637 ret = 0;
3638 }
3639 }
3640 if (!ret) {
3641 ret = write_one_cache_group(trans, root, path, cache);
3642 /*
3643 * Our block group might still be attached to the list
3644 * of new block groups in the transaction handle of some
3645 * other task (struct btrfs_trans_handle->new_bgs). This
3646 * means its block group item isn't yet in the extent
3647 * tree. If this happens ignore the error, as we will
3648 * try again later in the critical section of the
3649 * transaction commit.
3650 */
3651 if (ret == -ENOENT) {
3652 ret = 0;
3653 spin_lock(&cur_trans->dirty_bgs_lock);
3654 if (list_empty(&cache->dirty_list)) {
3655 list_add_tail(&cache->dirty_list,
3656 &cur_trans->dirty_bgs);
3657 btrfs_get_block_group(cache);
3658 }
3659 spin_unlock(&cur_trans->dirty_bgs_lock);
3660 } else if (ret) {
3661 btrfs_abort_transaction(trans, ret);
3662 }
3663 }
3664
3665 /* if its not on the io list, we need to put the block group */
3666 if (should_put)
3667 btrfs_put_block_group(cache);
3668
3669 if (ret)
3670 break;
3671
3672 /*
3673 * Avoid blocking other tasks for too long. It might even save
3674 * us from writing caches for block groups that are going to be
3675 * removed.
3676 */
3677 mutex_unlock(&trans->transaction->cache_write_mutex);
3678 mutex_lock(&trans->transaction->cache_write_mutex);
3679 }
3680 mutex_unlock(&trans->transaction->cache_write_mutex);
3681
3682 /*
3683 * go through delayed refs for all the stuff we've just kicked off
3684 * and then loop back (just once)
3685 */
3686 ret = btrfs_run_delayed_refs(trans, root, 0);
3687 if (!ret && loops == 0) {
3688 loops++;
3689 spin_lock(&cur_trans->dirty_bgs_lock);
3690 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3691 /*
3692 * dirty_bgs_lock protects us from concurrent block group
3693 * deletes too (not just cache_write_mutex).
3694 */
3695 if (!list_empty(&dirty)) {
3696 spin_unlock(&cur_trans->dirty_bgs_lock);
3697 goto again;
3698 }
3699 spin_unlock(&cur_trans->dirty_bgs_lock);
3700 } else if (ret < 0) {
3701 btrfs_cleanup_dirty_bgs(cur_trans, root);
3702 }
3703
3704 btrfs_free_path(path);
3705 return ret;
3706 }
3707
3708 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3709 struct btrfs_root *root)
3710 {
3711 struct btrfs_block_group_cache *cache;
3712 struct btrfs_transaction *cur_trans = trans->transaction;
3713 int ret = 0;
3714 int should_put;
3715 struct btrfs_path *path;
3716 struct list_head *io = &cur_trans->io_bgs;
3717 int num_started = 0;
3718
3719 path = btrfs_alloc_path();
3720 if (!path)
3721 return -ENOMEM;
3722
3723 /*
3724 * Even though we are in the critical section of the transaction commit,
3725 * we can still have concurrent tasks adding elements to this
3726 * transaction's list of dirty block groups. These tasks correspond to
3727 * endio free space workers started when writeback finishes for a
3728 * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
3729 * allocate new block groups as a result of COWing nodes of the root
3730 * tree when updating the free space inode. The writeback for the space
3731 * caches is triggered by an earlier call to
3732 * btrfs_start_dirty_block_groups() and iterations of the following
3733 * loop.
3734 * Also we want to do the cache_save_setup first and then run the
3735 * delayed refs to make sure we have the best chance at doing this all
3736 * in one shot.
3737 */
3738 spin_lock(&cur_trans->dirty_bgs_lock);
3739 while (!list_empty(&cur_trans->dirty_bgs)) {
3740 cache = list_first_entry(&cur_trans->dirty_bgs,
3741 struct btrfs_block_group_cache,
3742 dirty_list);
3743
3744 /*
3745 * this can happen if cache_save_setup re-dirties a block
3746 * group that is already under IO. Just wait for it to
3747 * finish and then do it all again
3748 */
3749 if (!list_empty(&cache->io_list)) {
3750 spin_unlock(&cur_trans->dirty_bgs_lock);
3751 list_del_init(&cache->io_list);
3752 btrfs_wait_cache_io(root, trans, cache,
3753 &cache->io_ctl, path,
3754 cache->key.objectid);
3755 btrfs_put_block_group(cache);
3756 spin_lock(&cur_trans->dirty_bgs_lock);
3757 }
3758
3759 /*
3760 * don't remove from the dirty list until after we've waited
3761 * on any pending IO
3762 */
3763 list_del_init(&cache->dirty_list);
3764 spin_unlock(&cur_trans->dirty_bgs_lock);
3765 should_put = 1;
3766
3767 cache_save_setup(cache, trans, path);
3768
3769 if (!ret)
3770 ret = btrfs_run_delayed_refs(trans, root, (unsigned long) -1);
3771
3772 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
3773 cache->io_ctl.inode = NULL;
3774 ret = btrfs_write_out_cache(root, trans, cache, path);
3775 if (ret == 0 && cache->io_ctl.inode) {
3776 num_started++;
3777 should_put = 0;
3778 list_add_tail(&cache->io_list, io);
3779 } else {
3780 /*
3781 * if we failed to write the cache, the
3782 * generation will be bad and life goes on
3783 */
3784 ret = 0;
3785 }
3786 }
3787 if (!ret) {
3788 ret = write_one_cache_group(trans, root, path, cache);
3789 /*
3790 * One of the free space endio workers might have
3791 * created a new block group while updating a free space
3792 * cache's inode (at inode.c:btrfs_finish_ordered_io())
3793 * and hasn't released its transaction handle yet, in
3794 * which case the new block group is still attached to
3795 * its transaction handle and its creation has not
3796 * finished yet (no block group item in the extent tree
3797 * yet, etc). If this is the case, wait for all free
3798 * space endio workers to finish and retry. This is a
3799 * a very rare case so no need for a more efficient and
3800 * complex approach.
3801 */
3802 if (ret == -ENOENT) {
3803 wait_event(cur_trans->writer_wait,
3804 atomic_read(&cur_trans->num_writers) == 1);
3805 ret = write_one_cache_group(trans, root, path,
3806 cache);
3807 }
3808 if (ret)
3809 btrfs_abort_transaction(trans, ret);
3810 }
3811
3812 /* if its not on the io list, we need to put the block group */
3813 if (should_put)
3814 btrfs_put_block_group(cache);
3815 spin_lock(&cur_trans->dirty_bgs_lock);
3816 }
3817 spin_unlock(&cur_trans->dirty_bgs_lock);
3818
3819 while (!list_empty(io)) {
3820 cache = list_first_entry(io, struct btrfs_block_group_cache,
3821 io_list);
3822 list_del_init(&cache->io_list);
3823 btrfs_wait_cache_io(root, trans, cache,
3824 &cache->io_ctl, path, cache->key.objectid);
3825 btrfs_put_block_group(cache);
3826 }
3827
3828 btrfs_free_path(path);
3829 return ret;
3830 }
3831
3832 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3833 {
3834 struct btrfs_block_group_cache *block_group;
3835 int readonly = 0;
3836
3837 block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3838 if (!block_group || block_group->ro)
3839 readonly = 1;
3840 if (block_group)
3841 btrfs_put_block_group(block_group);
3842 return readonly;
3843 }
3844
3845 bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3846 {
3847 struct btrfs_block_group_cache *bg;
3848 bool ret = true;
3849
3850 bg = btrfs_lookup_block_group(fs_info, bytenr);
3851 if (!bg)
3852 return false;
3853
3854 spin_lock(&bg->lock);
3855 if (bg->ro)
3856 ret = false;
3857 else
3858 atomic_inc(&bg->nocow_writers);
3859 spin_unlock(&bg->lock);
3860
3861 /* no put on block group, done by btrfs_dec_nocow_writers */
3862 if (!ret)
3863 btrfs_put_block_group(bg);
3864
3865 return ret;
3866
3867 }
3868
3869 void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3870 {
3871 struct btrfs_block_group_cache *bg;
3872
3873 bg = btrfs_lookup_block_group(fs_info, bytenr);
3874 ASSERT(bg);
3875 if (atomic_dec_and_test(&bg->nocow_writers))
3876 wake_up_atomic_t(&bg->nocow_writers);
3877 /*
3878 * Once for our lookup and once for the lookup done by a previous call
3879 * to btrfs_inc_nocow_writers()
3880 */
3881 btrfs_put_block_group(bg);
3882 btrfs_put_block_group(bg);
3883 }
3884
3885 static int btrfs_wait_nocow_writers_atomic_t(atomic_t *a)
3886 {
3887 schedule();
3888 return 0;
3889 }
3890
3891 void btrfs_wait_nocow_writers(struct btrfs_block_group_cache *bg)
3892 {
3893 wait_on_atomic_t(&bg->nocow_writers,
3894 btrfs_wait_nocow_writers_atomic_t,
3895 TASK_UNINTERRUPTIBLE);
3896 }
3897
3898 static const char *alloc_name(u64 flags)
3899 {
3900 switch (flags) {
3901 case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
3902 return "mixed";
3903 case BTRFS_BLOCK_GROUP_METADATA:
3904 return "metadata";
3905 case BTRFS_BLOCK_GROUP_DATA:
3906 return "data";
3907 case BTRFS_BLOCK_GROUP_SYSTEM:
3908 return "system";
3909 default:
3910 WARN_ON(1);
3911 return "invalid-combination";
3912 };
3913 }
3914
3915 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3916 u64 total_bytes, u64 bytes_used,
3917 u64 bytes_readonly,
3918 struct btrfs_space_info **space_info)
3919 {
3920 struct btrfs_space_info *found;
3921 int i;
3922 int factor;
3923 int ret;
3924
3925 if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3926 BTRFS_BLOCK_GROUP_RAID10))
3927 factor = 2;
3928 else
3929 factor = 1;
3930
3931 found = __find_space_info(info, flags);
3932 if (found) {
3933 spin_lock(&found->lock);
3934 found->total_bytes += total_bytes;
3935 found->disk_total += total_bytes * factor;
3936 found->bytes_used += bytes_used;
3937 found->disk_used += bytes_used * factor;
3938 found->bytes_readonly += bytes_readonly;
3939 if (total_bytes > 0)
3940 found->full = 0;
3941 space_info_add_new_bytes(info, found, total_bytes -
3942 bytes_used - bytes_readonly);
3943 spin_unlock(&found->lock);
3944 *space_info = found;
3945 return 0;
3946 }
3947 found = kzalloc(sizeof(*found), GFP_NOFS);
3948 if (!found)
3949 return -ENOMEM;
3950
3951 ret = percpu_counter_init(&found->total_bytes_pinned, 0, GFP_KERNEL);
3952 if (ret) {
3953 kfree(found);
3954 return ret;
3955 }
3956
3957 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3958 INIT_LIST_HEAD(&found->block_groups[i]);
3959 init_rwsem(&found->groups_sem);
3960 spin_lock_init(&found->lock);
3961 found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3962 found->total_bytes = total_bytes;
3963 found->disk_total = total_bytes * factor;
3964 found->bytes_used = bytes_used;
3965 found->disk_used = bytes_used * factor;
3966 found->bytes_pinned = 0;
3967 found->bytes_reserved = 0;
3968 found->bytes_readonly = bytes_readonly;
3969 found->bytes_may_use = 0;
3970 found->full = 0;
3971 found->max_extent_size = 0;
3972 found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3973 found->chunk_alloc = 0;
3974 found->flush = 0;
3975 init_waitqueue_head(&found->wait);
3976 INIT_LIST_HEAD(&found->ro_bgs);
3977 INIT_LIST_HEAD(&found->tickets);
3978 INIT_LIST_HEAD(&found->priority_tickets);
3979
3980 ret = kobject_init_and_add(&found->kobj, &space_info_ktype,
3981 info->space_info_kobj, "%s",
3982 alloc_name(found->flags));
3983 if (ret) {
3984 kfree(found);
3985 return ret;
3986 }
3987
3988 *space_info = found;
3989 list_add_rcu(&found->list, &info->space_info);
3990 if (flags & BTRFS_BLOCK_GROUP_DATA)
3991 info->data_sinfo = found;
3992
3993 return ret;
3994 }
3995
3996 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3997 {
3998 u64 extra_flags = chunk_to_extended(flags) &
3999 BTRFS_EXTENDED_PROFILE_MASK;
4000
4001 write_seqlock(&fs_info->profiles_lock);
4002 if (flags & BTRFS_BLOCK_GROUP_DATA)
4003 fs_info->avail_data_alloc_bits |= extra_flags;
4004 if (flags & BTRFS_BLOCK_GROUP_METADATA)
4005 fs_info->avail_metadata_alloc_bits |= extra_flags;
4006 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4007 fs_info->avail_system_alloc_bits |= extra_flags;
4008 write_sequnlock(&fs_info->profiles_lock);
4009 }
4010
4011 /*
4012 * returns target flags in extended format or 0 if restripe for this
4013 * chunk_type is not in progress
4014 *
4015 * should be called with either volume_mutex or balance_lock held
4016 */
4017 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
4018 {
4019 struct btrfs_balance_control *bctl = fs_info->balance_ctl;
4020 u64 target = 0;
4021
4022 if (!bctl)
4023 return 0;
4024
4025 if (flags & BTRFS_BLOCK_GROUP_DATA &&
4026 bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4027 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
4028 } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
4029 bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4030 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
4031 } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
4032 bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4033 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
4034 }
4035
4036 return target;
4037 }
4038
4039 /*
4040 * @flags: available profiles in extended format (see ctree.h)
4041 *
4042 * Returns reduced profile in chunk format. If profile changing is in
4043 * progress (either running or paused) picks the target profile (if it's
4044 * already available), otherwise falls back to plain reducing.
4045 */
4046 static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
4047 {
4048 u64 num_devices = root->fs_info->fs_devices->rw_devices;
4049 u64 target;
4050 u64 raid_type;
4051 u64 allowed = 0;
4052
4053 /*
4054 * see if restripe for this chunk_type is in progress, if so
4055 * try to reduce to the target profile
4056 */
4057 spin_lock(&root->fs_info->balance_lock);
4058 target = get_restripe_target(root->fs_info, flags);
4059 if (target) {
4060 /* pick target profile only if it's already available */
4061 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
4062 spin_unlock(&root->fs_info->balance_lock);
4063 return extended_to_chunk(target);
4064 }
4065 }
4066 spin_unlock(&root->fs_info->balance_lock);
4067
4068 /* First, mask out the RAID levels which aren't possible */
4069 for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
4070 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
4071 allowed |= btrfs_raid_group[raid_type];
4072 }
4073 allowed &= flags;
4074
4075 if (allowed & BTRFS_BLOCK_GROUP_RAID6)
4076 allowed = BTRFS_BLOCK_GROUP_RAID6;
4077 else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
4078 allowed = BTRFS_BLOCK_GROUP_RAID5;
4079 else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
4080 allowed = BTRFS_BLOCK_GROUP_RAID10;
4081 else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
4082 allowed = BTRFS_BLOCK_GROUP_RAID1;
4083 else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
4084 allowed = BTRFS_BLOCK_GROUP_RAID0;
4085
4086 flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
4087
4088 return extended_to_chunk(flags | allowed);
4089 }
4090
4091 static u64 get_alloc_profile(struct btrfs_root *root, u64 orig_flags)
4092 {
4093 unsigned seq;
4094 u64 flags;
4095
4096 do {
4097 flags = orig_flags;
4098 seq = read_seqbegin(&root->fs_info->profiles_lock);
4099
4100 if (flags & BTRFS_BLOCK_GROUP_DATA)
4101 flags |= root->fs_info->avail_data_alloc_bits;
4102 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4103 flags |= root->fs_info->avail_system_alloc_bits;
4104 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
4105 flags |= root->fs_info->avail_metadata_alloc_bits;
4106 } while (read_seqretry(&root->fs_info->profiles_lock, seq));
4107
4108 return btrfs_reduce_alloc_profile(root, flags);
4109 }
4110
4111 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
4112 {
4113 u64 flags;
4114 u64 ret;
4115
4116 if (data)
4117 flags = BTRFS_BLOCK_GROUP_DATA;
4118 else if (root == root->fs_info->chunk_root)
4119 flags = BTRFS_BLOCK_GROUP_SYSTEM;
4120 else
4121 flags = BTRFS_BLOCK_GROUP_METADATA;
4122
4123 ret = get_alloc_profile(root, flags);
4124 return ret;
4125 }
4126
4127 int btrfs_alloc_data_chunk_ondemand(struct inode *inode, u64 bytes)
4128 {
4129 struct btrfs_space_info *data_sinfo;
4130 struct btrfs_root *root = BTRFS_I(inode)->root;
4131 struct btrfs_fs_info *fs_info = root->fs_info;
4132 u64 used;
4133 int ret = 0;
4134 int need_commit = 2;
4135 int have_pinned_space;
4136
4137 /* make sure bytes are sectorsize aligned */
4138 bytes = ALIGN(bytes, root->sectorsize);
4139
4140 if (btrfs_is_free_space_inode(inode)) {
4141 need_commit = 0;
4142 ASSERT(current->journal_info);
4143 }
4144
4145 data_sinfo = fs_info->data_sinfo;
4146 if (!data_sinfo)
4147 goto alloc;
4148
4149 again:
4150 /* make sure we have enough space to handle the data first */
4151 spin_lock(&data_sinfo->lock);
4152 used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
4153 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
4154 data_sinfo->bytes_may_use;
4155
4156 if (used + bytes > data_sinfo->total_bytes) {
4157 struct btrfs_trans_handle *trans;
4158
4159 /*
4160 * if we don't have enough free bytes in this space then we need
4161 * to alloc a new chunk.
4162 */
4163 if (!data_sinfo->full) {
4164 u64 alloc_target;
4165
4166 data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
4167 spin_unlock(&data_sinfo->lock);
4168 alloc:
4169 alloc_target = btrfs_get_alloc_profile(root, 1);
4170 /*
4171 * It is ugly that we don't call nolock join
4172 * transaction for the free space inode case here.
4173 * But it is safe because we only do the data space
4174 * reservation for the free space cache in the
4175 * transaction context, the common join transaction
4176 * just increase the counter of the current transaction
4177 * handler, doesn't try to acquire the trans_lock of
4178 * the fs.
4179 */
4180 trans = btrfs_join_transaction(root);
4181 if (IS_ERR(trans))
4182 return PTR_ERR(trans);
4183
4184 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4185 alloc_target,
4186 CHUNK_ALLOC_NO_FORCE);
4187 btrfs_end_transaction(trans, root);
4188 if (ret < 0) {
4189 if (ret != -ENOSPC)
4190 return ret;
4191 else {
4192 have_pinned_space = 1;
4193 goto commit_trans;
4194 }
4195 }
4196
4197 if (!data_sinfo)
4198 data_sinfo = fs_info->data_sinfo;
4199
4200 goto again;
4201 }
4202
4203 /*
4204 * If we don't have enough pinned space to deal with this
4205 * allocation, and no removed chunk in current transaction,
4206 * don't bother committing the transaction.
4207 */
4208 have_pinned_space = percpu_counter_compare(
4209 &data_sinfo->total_bytes_pinned,
4210 used + bytes - data_sinfo->total_bytes);
4211 spin_unlock(&data_sinfo->lock);
4212
4213 /* commit the current transaction and try again */
4214 commit_trans:
4215 if (need_commit &&
4216 !atomic_read(&root->fs_info->open_ioctl_trans)) {
4217 need_commit--;
4218
4219 if (need_commit > 0) {
4220 btrfs_start_delalloc_roots(fs_info, 0, -1);
4221 btrfs_wait_ordered_roots(fs_info, -1, 0, (u64)-1);
4222 }
4223
4224 trans = btrfs_join_transaction(root);
4225 if (IS_ERR(trans))
4226 return PTR_ERR(trans);
4227 if (have_pinned_space >= 0 ||
4228 test_bit(BTRFS_TRANS_HAVE_FREE_BGS,
4229 &trans->transaction->flags) ||
4230 need_commit > 0) {
4231 ret = btrfs_commit_transaction(trans, root);
4232 if (ret)
4233 return ret;
4234 /*
4235 * The cleaner kthread might still be doing iput
4236 * operations. Wait for it to finish so that
4237 * more space is released.
4238 */
4239 mutex_lock(&root->fs_info->cleaner_delayed_iput_mutex);
4240 mutex_unlock(&root->fs_info->cleaner_delayed_iput_mutex);
4241 goto again;
4242 } else {
4243 btrfs_end_transaction(trans, root);
4244 }
4245 }
4246
4247 trace_btrfs_space_reservation(root->fs_info,
4248 "space_info:enospc",
4249 data_sinfo->flags, bytes, 1);
4250 return -ENOSPC;
4251 }
4252 data_sinfo->bytes_may_use += bytes;
4253 trace_btrfs_space_reservation(root->fs_info, "space_info",
4254 data_sinfo->flags, bytes, 1);
4255 spin_unlock(&data_sinfo->lock);
4256
4257 return ret;
4258 }
4259
4260 /*
4261 * New check_data_free_space() with ability for precious data reservation
4262 * Will replace old btrfs_check_data_free_space(), but for patch split,
4263 * add a new function first and then replace it.
4264 */
4265 int btrfs_check_data_free_space(struct inode *inode, u64 start, u64 len)
4266 {
4267 struct btrfs_root *root = BTRFS_I(inode)->root;
4268 int ret;
4269
4270 /* align the range */
4271 len = round_up(start + len, root->sectorsize) -
4272 round_down(start, root->sectorsize);
4273 start = round_down(start, root->sectorsize);
4274
4275 ret = btrfs_alloc_data_chunk_ondemand(inode, len);
4276 if (ret < 0)
4277 return ret;
4278
4279 /* Use new btrfs_qgroup_reserve_data to reserve precious data space. */
4280 ret = btrfs_qgroup_reserve_data(inode, start, len);
4281 if (ret)
4282 btrfs_free_reserved_data_space_noquota(inode, start, len);
4283 return ret;
4284 }
4285
4286 /*
4287 * Called if we need to clear a data reservation for this inode
4288 * Normally in a error case.
4289 *
4290 * This one will *NOT* use accurate qgroup reserved space API, just for case
4291 * which we can't sleep and is sure it won't affect qgroup reserved space.
4292 * Like clear_bit_hook().
4293 */
4294 void btrfs_free_reserved_data_space_noquota(struct inode *inode, u64 start,
4295 u64 len)
4296 {
4297 struct btrfs_root *root = BTRFS_I(inode)->root;
4298 struct btrfs_space_info *data_sinfo;
4299
4300 /* Make sure the range is aligned to sectorsize */
4301 len = round_up(start + len, root->sectorsize) -
4302 round_down(start, root->sectorsize);
4303 start = round_down(start, root->sectorsize);
4304
4305 data_sinfo = root->fs_info->data_sinfo;
4306 spin_lock(&data_sinfo->lock);
4307 if (WARN_ON(data_sinfo->bytes_may_use < len))
4308 data_sinfo->bytes_may_use = 0;
4309 else
4310 data_sinfo->bytes_may_use -= len;
4311 trace_btrfs_space_reservation(root->fs_info, "space_info",
4312 data_sinfo->flags, len, 0);
4313 spin_unlock(&data_sinfo->lock);
4314 }
4315
4316 /*
4317 * Called if we need to clear a data reservation for this inode
4318 * Normally in a error case.
4319 *
4320 * This one will handle the per-inode data rsv map for accurate reserved
4321 * space framework.
4322 */
4323 void btrfs_free_reserved_data_space(struct inode *inode, u64 start, u64 len)
4324 {
4325 btrfs_free_reserved_data_space_noquota(inode, start, len);
4326 btrfs_qgroup_free_data(inode, start, len);
4327 }
4328
4329 static void force_metadata_allocation(struct btrfs_fs_info *info)
4330 {
4331 struct list_head *head = &info->space_info;
4332 struct btrfs_space_info *found;
4333
4334 rcu_read_lock();
4335 list_for_each_entry_rcu(found, head, list) {
4336 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
4337 found->force_alloc = CHUNK_ALLOC_FORCE;
4338 }
4339 rcu_read_unlock();
4340 }
4341
4342 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
4343 {
4344 return (global->size << 1);
4345 }
4346
4347 static int should_alloc_chunk(struct btrfs_root *root,
4348 struct btrfs_space_info *sinfo, int force)
4349 {
4350 struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4351 u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
4352 u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
4353 u64 thresh;
4354
4355 if (force == CHUNK_ALLOC_FORCE)
4356 return 1;
4357
4358 /*
4359 * We need to take into account the global rsv because for all intents
4360 * and purposes it's used space. Don't worry about locking the
4361 * global_rsv, it doesn't change except when the transaction commits.
4362 */
4363 if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
4364 num_allocated += calc_global_rsv_need_space(global_rsv);
4365
4366 /*
4367 * in limited mode, we want to have some free space up to
4368 * about 1% of the FS size.
4369 */
4370 if (force == CHUNK_ALLOC_LIMITED) {
4371 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
4372 thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
4373
4374 if (num_bytes - num_allocated < thresh)
4375 return 1;
4376 }
4377
4378 if (num_allocated + SZ_2M < div_factor(num_bytes, 8))
4379 return 0;
4380 return 1;
4381 }
4382
4383 static u64 get_profile_num_devs(struct btrfs_root *root, u64 type)
4384 {
4385 u64 num_dev;
4386
4387 if (type & (BTRFS_BLOCK_GROUP_RAID10 |
4388 BTRFS_BLOCK_GROUP_RAID0 |
4389 BTRFS_BLOCK_GROUP_RAID5 |
4390 BTRFS_BLOCK_GROUP_RAID6))
4391 num_dev = root->fs_info->fs_devices->rw_devices;
4392 else if (type & BTRFS_BLOCK_GROUP_RAID1)
4393 num_dev = 2;
4394 else
4395 num_dev = 1; /* DUP or single */
4396
4397 return num_dev;
4398 }
4399
4400 /*
4401 * If @is_allocation is true, reserve space in the system space info necessary
4402 * for allocating a chunk, otherwise if it's false, reserve space necessary for
4403 * removing a chunk.
4404 */
4405 void check_system_chunk(struct btrfs_trans_handle *trans,
4406 struct btrfs_root *root,
4407 u64 type)
4408 {
4409 struct btrfs_space_info *info;
4410 u64 left;
4411 u64 thresh;
4412 int ret = 0;
4413 u64 num_devs;
4414
4415 /*
4416 * Needed because we can end up allocating a system chunk and for an
4417 * atomic and race free space reservation in the chunk block reserve.
4418 */
4419 ASSERT(mutex_is_locked(&root->fs_info->chunk_mutex));
4420
4421 info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4422 spin_lock(&info->lock);
4423 left = info->total_bytes - info->bytes_used - info->bytes_pinned -
4424 info->bytes_reserved - info->bytes_readonly -
4425 info->bytes_may_use;
4426 spin_unlock(&info->lock);
4427
4428 num_devs = get_profile_num_devs(root, type);
4429
4430 /* num_devs device items to update and 1 chunk item to add or remove */
4431 thresh = btrfs_calc_trunc_metadata_size(root, num_devs) +
4432 btrfs_calc_trans_metadata_size(root, 1);
4433
4434 if (left < thresh && btrfs_test_opt(root->fs_info, ENOSPC_DEBUG)) {
4435 btrfs_info(root->fs_info, "left=%llu, need=%llu, flags=%llu",
4436 left, thresh, type);
4437 dump_space_info(root->fs_info, info, 0, 0);
4438 }
4439
4440 if (left < thresh) {
4441 u64 flags;
4442
4443 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
4444 /*
4445 * Ignore failure to create system chunk. We might end up not
4446 * needing it, as we might not need to COW all nodes/leafs from
4447 * the paths we visit in the chunk tree (they were already COWed
4448 * or created in the current transaction for example).
4449 */
4450 ret = btrfs_alloc_chunk(trans, root, flags);
4451 }
4452
4453 if (!ret) {
4454 ret = btrfs_block_rsv_add(root->fs_info->chunk_root,
4455 &root->fs_info->chunk_block_rsv,
4456 thresh, BTRFS_RESERVE_NO_FLUSH);
4457 if (!ret)
4458 trans->chunk_bytes_reserved += thresh;
4459 }
4460 }
4461
4462 /*
4463 * If force is CHUNK_ALLOC_FORCE:
4464 * - return 1 if it successfully allocates a chunk,
4465 * - return errors including -ENOSPC otherwise.
4466 * If force is NOT CHUNK_ALLOC_FORCE:
4467 * - return 0 if it doesn't need to allocate a new chunk,
4468 * - return 1 if it successfully allocates a chunk,
4469 * - return errors including -ENOSPC otherwise.
4470 */
4471 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
4472 struct btrfs_root *extent_root, u64 flags, int force)
4473 {
4474 struct btrfs_space_info *space_info;
4475 struct btrfs_fs_info *fs_info = extent_root->fs_info;
4476 int wait_for_alloc = 0;
4477 int ret = 0;
4478
4479 /* Don't re-enter if we're already allocating a chunk */
4480 if (trans->allocating_chunk)
4481 return -ENOSPC;
4482
4483 space_info = __find_space_info(extent_root->fs_info, flags);
4484 if (!space_info) {
4485 ret = update_space_info(extent_root->fs_info, flags,
4486 0, 0, 0, &space_info);
4487 BUG_ON(ret); /* -ENOMEM */
4488 }
4489 BUG_ON(!space_info); /* Logic error */
4490
4491 again:
4492 spin_lock(&space_info->lock);
4493 if (force < space_info->force_alloc)
4494 force = space_info->force_alloc;
4495 if (space_info->full) {
4496 if (should_alloc_chunk(extent_root, space_info, force))
4497 ret = -ENOSPC;
4498 else
4499 ret = 0;
4500 spin_unlock(&space_info->lock);
4501 return ret;
4502 }
4503
4504 if (!should_alloc_chunk(extent_root, space_info, force)) {
4505 spin_unlock(&space_info->lock);
4506 return 0;
4507 } else if (space_info->chunk_alloc) {
4508 wait_for_alloc = 1;
4509 } else {
4510 space_info->chunk_alloc = 1;
4511 }
4512
4513 spin_unlock(&space_info->lock);
4514
4515 mutex_lock(&fs_info->chunk_mutex);
4516
4517 /*
4518 * The chunk_mutex is held throughout the entirety of a chunk
4519 * allocation, so once we've acquired the chunk_mutex we know that the
4520 * other guy is done and we need to recheck and see if we should
4521 * allocate.
4522 */
4523 if (wait_for_alloc) {
4524 mutex_unlock(&fs_info->chunk_mutex);
4525 wait_for_alloc = 0;
4526 goto again;
4527 }
4528
4529 trans->allocating_chunk = true;
4530
4531 /*
4532 * If we have mixed data/metadata chunks we want to make sure we keep
4533 * allocating mixed chunks instead of individual chunks.
4534 */
4535 if (btrfs_mixed_space_info(space_info))
4536 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
4537
4538 /*
4539 * if we're doing a data chunk, go ahead and make sure that
4540 * we keep a reasonable number of metadata chunks allocated in the
4541 * FS as well.
4542 */
4543 if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
4544 fs_info->data_chunk_allocations++;
4545 if (!(fs_info->data_chunk_allocations %
4546 fs_info->metadata_ratio))
4547 force_metadata_allocation(fs_info);
4548 }
4549
4550 /*
4551 * Check if we have enough space in SYSTEM chunk because we may need
4552 * to update devices.
4553 */
4554 check_system_chunk(trans, extent_root, flags);
4555
4556 ret = btrfs_alloc_chunk(trans, extent_root, flags);
4557 trans->allocating_chunk = false;
4558
4559 spin_lock(&space_info->lock);
4560 if (ret < 0 && ret != -ENOSPC)
4561 goto out;
4562 if (ret)
4563 space_info->full = 1;
4564 else
4565 ret = 1;
4566
4567 space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4568 out:
4569 space_info->chunk_alloc = 0;
4570 spin_unlock(&space_info->lock);
4571 mutex_unlock(&fs_info->chunk_mutex);
4572 /*
4573 * When we allocate a new chunk we reserve space in the chunk block
4574 * reserve to make sure we can COW nodes/leafs in the chunk tree or
4575 * add new nodes/leafs to it if we end up needing to do it when
4576 * inserting the chunk item and updating device items as part of the
4577 * second phase of chunk allocation, performed by
4578 * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
4579 * large number of new block groups to create in our transaction
4580 * handle's new_bgs list to avoid exhausting the chunk block reserve
4581 * in extreme cases - like having a single transaction create many new
4582 * block groups when starting to write out the free space caches of all
4583 * the block groups that were made dirty during the lifetime of the
4584 * transaction.
4585 */
4586 if (trans->can_flush_pending_bgs &&
4587 trans->chunk_bytes_reserved >= (u64)SZ_2M) {
4588 btrfs_create_pending_block_groups(trans, extent_root);
4589 btrfs_trans_release_chunk_metadata(trans);
4590 }
4591 return ret;
4592 }
4593
4594 static int can_overcommit(struct btrfs_root *root,
4595 struct btrfs_space_info *space_info, u64 bytes,
4596 enum btrfs_reserve_flush_enum flush)
4597 {
4598 struct btrfs_block_rsv *global_rsv;
4599 u64 profile;
4600 u64 space_size;
4601 u64 avail;
4602 u64 used;
4603
4604 /* Don't overcommit when in mixed mode. */
4605 if (space_info->flags & BTRFS_BLOCK_GROUP_DATA)
4606 return 0;
4607
4608 BUG_ON(root->fs_info == NULL);
4609 global_rsv = &root->fs_info->global_block_rsv;
4610 profile = btrfs_get_alloc_profile(root, 0);
4611 used = space_info->bytes_used + space_info->bytes_reserved +
4612 space_info->bytes_pinned + space_info->bytes_readonly;
4613
4614 /*
4615 * We only want to allow over committing if we have lots of actual space
4616 * free, but if we don't have enough space to handle the global reserve
4617 * space then we could end up having a real enospc problem when trying
4618 * to allocate a chunk or some other such important allocation.
4619 */
4620 spin_lock(&global_rsv->lock);
4621 space_size = calc_global_rsv_need_space(global_rsv);
4622 spin_unlock(&global_rsv->lock);
4623 if (used + space_size >= space_info->total_bytes)
4624 return 0;
4625
4626 used += space_info->bytes_may_use;
4627
4628 spin_lock(&root->fs_info->free_chunk_lock);
4629 avail = root->fs_info->free_chunk_space;
4630 spin_unlock(&root->fs_info->free_chunk_lock);
4631
4632 /*
4633 * If we have dup, raid1 or raid10 then only half of the free
4634 * space is actually useable. For raid56, the space info used
4635 * doesn't include the parity drive, so we don't have to
4636 * change the math
4637 */
4638 if (profile & (BTRFS_BLOCK_GROUP_DUP |
4639 BTRFS_BLOCK_GROUP_RAID1 |
4640 BTRFS_BLOCK_GROUP_RAID10))
4641 avail >>= 1;
4642
4643 /*
4644 * If we aren't flushing all things, let us overcommit up to
4645 * 1/2th of the space. If we can flush, don't let us overcommit
4646 * too much, let it overcommit up to 1/8 of the space.
4647 */
4648 if (flush == BTRFS_RESERVE_FLUSH_ALL)
4649 avail >>= 3;
4650 else
4651 avail >>= 1;
4652
4653 if (used + bytes < space_info->total_bytes + avail)
4654 return 1;
4655 return 0;
4656 }
4657
4658 static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
4659 unsigned long nr_pages, int nr_items)
4660 {
4661 struct super_block *sb = root->fs_info->sb;
4662
4663 if (down_read_trylock(&sb->s_umount)) {
4664 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
4665 up_read(&sb->s_umount);
4666 } else {
4667 /*
4668 * We needn't worry the filesystem going from r/w to r/o though
4669 * we don't acquire ->s_umount mutex, because the filesystem
4670 * should guarantee the delalloc inodes list be empty after
4671 * the filesystem is readonly(all dirty pages are written to
4672 * the disk).
4673 */
4674 btrfs_start_delalloc_roots(root->fs_info, 0, nr_items);
4675 if (!current->journal_info)
4676 btrfs_wait_ordered_roots(root->fs_info, nr_items,
4677 0, (u64)-1);
4678 }
4679 }
4680
4681 static inline int calc_reclaim_items_nr(struct btrfs_root *root, u64 to_reclaim)
4682 {
4683 u64 bytes;
4684 int nr;
4685
4686 bytes = btrfs_calc_trans_metadata_size(root, 1);
4687 nr = (int)div64_u64(to_reclaim, bytes);
4688 if (!nr)
4689 nr = 1;
4690 return nr;
4691 }
4692
4693 #define EXTENT_SIZE_PER_ITEM SZ_256K
4694
4695 /*
4696 * shrink metadata reservation for delalloc
4697 */
4698 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
4699 bool wait_ordered)
4700 {
4701 struct btrfs_block_rsv *block_rsv;
4702 struct btrfs_space_info *space_info;
4703 struct btrfs_trans_handle *trans;
4704 u64 delalloc_bytes;
4705 u64 max_reclaim;
4706 long time_left;
4707 unsigned long nr_pages;
4708 int loops;
4709 int items;
4710 enum btrfs_reserve_flush_enum flush;
4711
4712 /* Calc the number of the pages we need flush for space reservation */
4713 items = calc_reclaim_items_nr(root, to_reclaim);
4714 to_reclaim = (u64)items * EXTENT_SIZE_PER_ITEM;
4715
4716 trans = (struct btrfs_trans_handle *)current->journal_info;
4717 block_rsv = &root->fs_info->delalloc_block_rsv;
4718 space_info = block_rsv->space_info;
4719
4720 delalloc_bytes = percpu_counter_sum_positive(
4721 &root->fs_info->delalloc_bytes);
4722 if (delalloc_bytes == 0) {
4723 if (trans)
4724 return;
4725 if (wait_ordered)
4726 btrfs_wait_ordered_roots(root->fs_info, items,
4727 0, (u64)-1);
4728 return;
4729 }
4730
4731 loops = 0;
4732 while (delalloc_bytes && loops < 3) {
4733 max_reclaim = min(delalloc_bytes, to_reclaim);
4734 nr_pages = max_reclaim >> PAGE_SHIFT;
4735 btrfs_writeback_inodes_sb_nr(root, nr_pages, items);
4736 /*
4737 * We need to wait for the async pages to actually start before
4738 * we do anything.
4739 */
4740 max_reclaim = atomic_read(&root->fs_info->async_delalloc_pages);
4741 if (!max_reclaim)
4742 goto skip_async;
4743
4744 if (max_reclaim <= nr_pages)
4745 max_reclaim = 0;
4746 else
4747 max_reclaim -= nr_pages;
4748
4749 wait_event(root->fs_info->async_submit_wait,
4750 atomic_read(&root->fs_info->async_delalloc_pages) <=
4751 (int)max_reclaim);
4752 skip_async:
4753 if (!trans)
4754 flush = BTRFS_RESERVE_FLUSH_ALL;
4755 else
4756 flush = BTRFS_RESERVE_NO_FLUSH;
4757 spin_lock(&space_info->lock);
4758 if (can_overcommit(root, space_info, orig, flush)) {
4759 spin_unlock(&space_info->lock);
4760 break;
4761 }
4762 if (list_empty(&space_info->tickets) &&
4763 list_empty(&space_info->priority_tickets)) {
4764 spin_unlock(&space_info->lock);
4765 break;
4766 }
4767 spin_unlock(&space_info->lock);
4768
4769 loops++;
4770 if (wait_ordered && !trans) {
4771 btrfs_wait_ordered_roots(root->fs_info, items,
4772 0, (u64)-1);
4773 } else {
4774 time_left = schedule_timeout_killable(1);
4775 if (time_left)
4776 break;
4777 }
4778 delalloc_bytes = percpu_counter_sum_positive(
4779 &root->fs_info->delalloc_bytes);
4780 }
4781 }
4782
4783 /**
4784 * maybe_commit_transaction - possibly commit the transaction if its ok to
4785 * @root - the root we're allocating for
4786 * @bytes - the number of bytes we want to reserve
4787 * @force - force the commit
4788 *
4789 * This will check to make sure that committing the transaction will actually
4790 * get us somewhere and then commit the transaction if it does. Otherwise it
4791 * will return -ENOSPC.
4792 */
4793 static int may_commit_transaction(struct btrfs_root *root,
4794 struct btrfs_space_info *space_info,
4795 u64 bytes, int force)
4796 {
4797 struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
4798 struct btrfs_trans_handle *trans;
4799
4800 trans = (struct btrfs_trans_handle *)current->journal_info;
4801 if (trans)
4802 return -EAGAIN;
4803
4804 if (force)
4805 goto commit;
4806
4807 /* See if there is enough pinned space to make this reservation */
4808 if (percpu_counter_compare(&space_info->total_bytes_pinned,
4809 bytes) >= 0)
4810 goto commit;
4811
4812 /*
4813 * See if there is some space in the delayed insertion reservation for
4814 * this reservation.
4815 */
4816 if (space_info != delayed_rsv->space_info)
4817 return -ENOSPC;
4818
4819 spin_lock(&delayed_rsv->lock);
4820 if (percpu_counter_compare(&space_info->total_bytes_pinned,
4821 bytes - delayed_rsv->size) >= 0) {
4822 spin_unlock(&delayed_rsv->lock);
4823 return -ENOSPC;
4824 }
4825 spin_unlock(&delayed_rsv->lock);
4826
4827 commit:
4828 trans = btrfs_join_transaction(root);
4829 if (IS_ERR(trans))
4830 return -ENOSPC;
4831
4832 return btrfs_commit_transaction(trans, root);
4833 }
4834
4835 struct reserve_ticket {
4836 u64 bytes;
4837 int error;
4838 struct list_head list;
4839 wait_queue_head_t wait;
4840 };
4841
4842 static int flush_space(struct btrfs_root *root,
4843 struct btrfs_space_info *space_info, u64 num_bytes,
4844 u64 orig_bytes, int state)
4845 {
4846 struct btrfs_trans_handle *trans;
4847 int nr;
4848 int ret = 0;
4849
4850 switch (state) {
4851 case FLUSH_DELAYED_ITEMS_NR:
4852 case FLUSH_DELAYED_ITEMS:
4853 if (state == FLUSH_DELAYED_ITEMS_NR)
4854 nr = calc_reclaim_items_nr(root, num_bytes) * 2;
4855 else
4856 nr = -1;
4857
4858 trans = btrfs_join_transaction(root);
4859 if (IS_ERR(trans)) {
4860 ret = PTR_ERR(trans);
4861 break;
4862 }
4863 ret = btrfs_run_delayed_items_nr(trans, root, nr);
4864 btrfs_end_transaction(trans, root);
4865 break;
4866 case FLUSH_DELALLOC:
4867 case FLUSH_DELALLOC_WAIT:
4868 shrink_delalloc(root, num_bytes * 2, orig_bytes,
4869 state == FLUSH_DELALLOC_WAIT);
4870 break;
4871 case ALLOC_CHUNK:
4872 trans = btrfs_join_transaction(root);
4873 if (IS_ERR(trans)) {
4874 ret = PTR_ERR(trans);
4875 break;
4876 }
4877 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4878 btrfs_get_alloc_profile(root, 0),
4879 CHUNK_ALLOC_NO_FORCE);
4880 btrfs_end_transaction(trans, root);
4881 if (ret > 0 || ret == -ENOSPC)
4882 ret = 0;
4883 break;
4884 case COMMIT_TRANS:
4885 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
4886 break;
4887 default:
4888 ret = -ENOSPC;
4889 break;
4890 }
4891
4892 trace_btrfs_flush_space(root->fs_info, space_info->flags, num_bytes,
4893 orig_bytes, state, ret);
4894 return ret;
4895 }
4896
4897 static inline u64
4898 btrfs_calc_reclaim_metadata_size(struct btrfs_root *root,
4899 struct btrfs_space_info *space_info)
4900 {
4901 struct reserve_ticket *ticket;
4902 u64 used;
4903 u64 expected;
4904 u64 to_reclaim = 0;
4905
4906 list_for_each_entry(ticket, &space_info->tickets, list)
4907 to_reclaim += ticket->bytes;
4908 list_for_each_entry(ticket, &space_info->priority_tickets, list)
4909 to_reclaim += ticket->bytes;
4910 if (to_reclaim)
4911 return to_reclaim;
4912
4913 to_reclaim = min_t(u64, num_online_cpus() * SZ_1M, SZ_16M);
4914 if (can_overcommit(root, space_info, to_reclaim,
4915 BTRFS_RESERVE_FLUSH_ALL))
4916 return 0;
4917
4918 used = space_info->bytes_used + space_info->bytes_reserved +
4919 space_info->bytes_pinned + space_info->bytes_readonly +
4920 space_info->bytes_may_use;
4921 if (can_overcommit(root, space_info, SZ_1M, BTRFS_RESERVE_FLUSH_ALL))
4922 expected = div_factor_fine(space_info->total_bytes, 95);
4923 else
4924 expected = div_factor_fine(space_info->total_bytes, 90);
4925
4926 if (used > expected)
4927 to_reclaim = used - expected;
4928 else
4929 to_reclaim = 0;
4930 to_reclaim = min(to_reclaim, space_info->bytes_may_use +
4931 space_info->bytes_reserved);
4932 return to_reclaim;
4933 }
4934
4935 static inline int need_do_async_reclaim(struct btrfs_space_info *space_info,
4936 struct btrfs_root *root, u64 used)
4937 {
4938 u64 thresh = div_factor_fine(space_info->total_bytes, 98);
4939
4940 /* If we're just plain full then async reclaim just slows us down. */
4941 if ((space_info->bytes_used + space_info->bytes_reserved) >= thresh)
4942 return 0;
4943
4944 if (!btrfs_calc_reclaim_metadata_size(root, space_info))
4945 return 0;
4946
4947 return (used >= thresh && !btrfs_fs_closing(root->fs_info) &&
4948 !test_bit(BTRFS_FS_STATE_REMOUNTING,
4949 &root->fs_info->fs_state));
4950 }
4951
4952 static void wake_all_tickets(struct list_head *head)
4953 {
4954 struct reserve_ticket *ticket;
4955
4956 while (!list_empty(head)) {
4957 ticket = list_first_entry(head, struct reserve_ticket, list);
4958 list_del_init(&ticket->list);
4959 ticket->error = -ENOSPC;
4960 wake_up(&ticket->wait);
4961 }
4962 }
4963
4964 /*
4965 * This is for normal flushers, we can wait all goddamned day if we want to. We
4966 * will loop and continuously try to flush as long as we are making progress.
4967 * We count progress as clearing off tickets each time we have to loop.
4968 */
4969 static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
4970 {
4971 struct btrfs_fs_info *fs_info;
4972 struct btrfs_space_info *space_info;
4973 u64 to_reclaim;
4974 int flush_state;
4975 int commit_cycles = 0;
4976 u64 last_tickets_id;
4977
4978 fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
4979 space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4980
4981 spin_lock(&space_info->lock);
4982 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
4983 space_info);
4984 if (!to_reclaim) {
4985 space_info->flush = 0;
4986 spin_unlock(&space_info->lock);
4987 return;
4988 }
4989 last_tickets_id = space_info->tickets_id;
4990 spin_unlock(&space_info->lock);
4991
4992 flush_state = FLUSH_DELAYED_ITEMS_NR;
4993 do {
4994 struct reserve_ticket *ticket;
4995 int ret;
4996
4997 ret = flush_space(fs_info->fs_root, space_info, to_reclaim,
4998 to_reclaim, flush_state);
4999 spin_lock(&space_info->lock);
5000 if (list_empty(&space_info->tickets)) {
5001 space_info->flush = 0;
5002 spin_unlock(&space_info->lock);
5003 return;
5004 }
5005 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
5006 space_info);
5007 ticket = list_first_entry(&space_info->tickets,
5008 struct reserve_ticket, list);
5009 if (last_tickets_id == space_info->tickets_id) {
5010 flush_state++;
5011 } else {
5012 last_tickets_id = space_info->tickets_id;
5013 flush_state = FLUSH_DELAYED_ITEMS_NR;
5014 if (commit_cycles)
5015 commit_cycles--;
5016 }
5017
5018 if (flush_state > COMMIT_TRANS) {
5019 commit_cycles++;
5020 if (commit_cycles > 2) {
5021 wake_all_tickets(&space_info->tickets);
5022 space_info->flush = 0;
5023 } else {
5024 flush_state = FLUSH_DELAYED_ITEMS_NR;
5025 }
5026 }
5027 spin_unlock(&space_info->lock);
5028 } while (flush_state <= COMMIT_TRANS);
5029 }
5030
5031 void btrfs_init_async_reclaim_work(struct work_struct *work)
5032 {
5033 INIT_WORK(work, btrfs_async_reclaim_metadata_space);
5034 }
5035
5036 static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
5037 struct btrfs_space_info *space_info,
5038 struct reserve_ticket *ticket)
5039 {
5040 u64 to_reclaim;
5041 int flush_state = FLUSH_DELAYED_ITEMS_NR;
5042
5043 spin_lock(&space_info->lock);
5044 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
5045 space_info);
5046 if (!to_reclaim) {
5047 spin_unlock(&space_info->lock);
5048 return;
5049 }
5050 spin_unlock(&space_info->lock);
5051
5052 do {
5053 flush_space(fs_info->fs_root, space_info, to_reclaim,
5054 to_reclaim, flush_state);
5055 flush_state++;
5056 spin_lock(&space_info->lock);
5057 if (ticket->bytes == 0) {
5058 spin_unlock(&space_info->lock);
5059 return;
5060 }
5061 spin_unlock(&space_info->lock);
5062
5063 /*
5064 * Priority flushers can't wait on delalloc without
5065 * deadlocking.
5066 */
5067 if (flush_state == FLUSH_DELALLOC ||
5068 flush_state == FLUSH_DELALLOC_WAIT)
5069 flush_state = ALLOC_CHUNK;
5070 } while (flush_state < COMMIT_TRANS);
5071 }
5072
5073 static int wait_reserve_ticket(struct btrfs_fs_info *fs_info,
5074 struct btrfs_space_info *space_info,
5075 struct reserve_ticket *ticket, u64 orig_bytes)
5076
5077 {
5078 DEFINE_WAIT(wait);
5079 int ret = 0;
5080
5081 spin_lock(&space_info->lock);
5082 while (ticket->bytes > 0 && ticket->error == 0) {
5083 ret = prepare_to_wait_event(&ticket->wait, &wait, TASK_KILLABLE);
5084 if (ret) {
5085 ret = -EINTR;
5086 break;
5087 }
5088 spin_unlock(&space_info->lock);
5089
5090 schedule();
5091
5092 finish_wait(&ticket->wait, &wait);
5093 spin_lock(&space_info->lock);
5094 }
5095 if (!ret)
5096 ret = ticket->error;
5097 if (!list_empty(&ticket->list))
5098 list_del_init(&ticket->list);
5099 if (ticket->bytes && ticket->bytes < orig_bytes) {
5100 u64 num_bytes = orig_bytes - ticket->bytes;
5101 space_info->bytes_may_use -= num_bytes;
5102 trace_btrfs_space_reservation(fs_info, "space_info",
5103 space_info->flags, num_bytes, 0);
5104 }
5105 spin_unlock(&space_info->lock);
5106
5107 return ret;
5108 }
5109
5110 /**
5111 * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5112 * @root - the root we're allocating for
5113 * @space_info - the space info we want to allocate from
5114 * @orig_bytes - the number of bytes we want
5115 * @flush - whether or not we can flush to make our reservation
5116 *
5117 * This will reserve orig_bytes number of bytes from the space info associated
5118 * with the block_rsv. If there is not enough space it will make an attempt to
5119 * flush out space to make room. It will do this by flushing delalloc if
5120 * possible or committing the transaction. If flush is 0 then no attempts to
5121 * regain reservations will be made and this will fail if there is not enough
5122 * space already.
5123 */
5124 static int __reserve_metadata_bytes(struct btrfs_root *root,
5125 struct btrfs_space_info *space_info,
5126 u64 orig_bytes,
5127 enum btrfs_reserve_flush_enum flush)
5128 {
5129 struct reserve_ticket ticket;
5130 u64 used;
5131 int ret = 0;
5132
5133 ASSERT(orig_bytes);
5134 ASSERT(!current->journal_info || flush != BTRFS_RESERVE_FLUSH_ALL);
5135
5136 spin_lock(&space_info->lock);
5137 ret = -ENOSPC;
5138 used = space_info->bytes_used + space_info->bytes_reserved +
5139 space_info->bytes_pinned + space_info->bytes_readonly +
5140 space_info->bytes_may_use;
5141
5142 /*
5143 * If we have enough space then hooray, make our reservation and carry
5144 * on. If not see if we can overcommit, and if we can, hooray carry on.
5145 * If not things get more complicated.
5146 */
5147 if (used + orig_bytes <= space_info->total_bytes) {
5148 space_info->bytes_may_use += orig_bytes;
5149 trace_btrfs_space_reservation(root->fs_info, "space_info",
5150 space_info->flags, orig_bytes,
5151 1);
5152 ret = 0;
5153 } else if (can_overcommit(root, space_info, orig_bytes, flush)) {
5154 space_info->bytes_may_use += orig_bytes;
5155 trace_btrfs_space_reservation(root->fs_info, "space_info",
5156 space_info->flags, orig_bytes,
5157 1);
5158 ret = 0;
5159 }
5160
5161 /*
5162 * If we couldn't make a reservation then setup our reservation ticket
5163 * and kick the async worker if it's not already running.
5164 *
5165 * If we are a priority flusher then we just need to add our ticket to
5166 * the list and we will do our own flushing further down.
5167 */
5168 if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
5169 ticket.bytes = orig_bytes;
5170 ticket.error = 0;
5171 init_waitqueue_head(&ticket.wait);
5172 if (flush == BTRFS_RESERVE_FLUSH_ALL) {
5173 list_add_tail(&ticket.list, &space_info->tickets);
5174 if (!space_info->flush) {
5175 space_info->flush = 1;
5176 trace_btrfs_trigger_flush(root->fs_info,
5177 space_info->flags,
5178 orig_bytes, flush,
5179 "enospc");
5180 queue_work(system_unbound_wq,
5181 &root->fs_info->async_reclaim_work);
5182 }
5183 } else {
5184 list_add_tail(&ticket.list,
5185 &space_info->priority_tickets);
5186 }
5187 } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
5188 used += orig_bytes;
5189 /*
5190 * We will do the space reservation dance during log replay,
5191 * which means we won't have fs_info->fs_root set, so don't do
5192 * the async reclaim as we will panic.
5193 */
5194 if (!test_bit(BTRFS_FS_LOG_RECOVERING, &root->fs_info->flags) &&
5195 need_do_async_reclaim(space_info, root, used) &&
5196 !work_busy(&root->fs_info->async_reclaim_work)) {
5197 trace_btrfs_trigger_flush(root->fs_info,
5198 space_info->flags,
5199 orig_bytes, flush,
5200 "preempt");
5201 queue_work(system_unbound_wq,
5202 &root->fs_info->async_reclaim_work);
5203 }
5204 }
5205 spin_unlock(&space_info->lock);
5206 if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
5207 return ret;
5208
5209 if (flush == BTRFS_RESERVE_FLUSH_ALL)
5210 return wait_reserve_ticket(root->fs_info, space_info, &ticket,
5211 orig_bytes);
5212
5213 ret = 0;
5214 priority_reclaim_metadata_space(root->fs_info, space_info, &ticket);
5215 spin_lock(&space_info->lock);
5216 if (ticket.bytes) {
5217 if (ticket.bytes < orig_bytes) {
5218 u64 num_bytes = orig_bytes - ticket.bytes;
5219 space_info->bytes_may_use -= num_bytes;
5220 trace_btrfs_space_reservation(root->fs_info,
5221 "space_info", space_info->flags,
5222 num_bytes, 0);
5223
5224 }
5225 list_del_init(&ticket.list);
5226 ret = -ENOSPC;
5227 }
5228 spin_unlock(&space_info->lock);
5229 ASSERT(list_empty(&ticket.list));
5230 return ret;
5231 }
5232
5233 /**
5234 * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5235 * @root - the root we're allocating for
5236 * @block_rsv - the block_rsv we're allocating for
5237 * @orig_bytes - the number of bytes we want
5238 * @flush - whether or not we can flush to make our reservation
5239 *
5240 * This will reserve orgi_bytes number of bytes from the space info associated
5241 * with the block_rsv. If there is not enough space it will make an attempt to
5242 * flush out space to make room. It will do this by flushing delalloc if
5243 * possible or committing the transaction. If flush is 0 then no attempts to
5244 * regain reservations will be made and this will fail if there is not enough
5245 * space already.
5246 */
5247 static int reserve_metadata_bytes(struct btrfs_root *root,
5248 struct btrfs_block_rsv *block_rsv,
5249 u64 orig_bytes,
5250 enum btrfs_reserve_flush_enum flush)
5251 {
5252 int ret;
5253
5254 ret = __reserve_metadata_bytes(root, block_rsv->space_info, orig_bytes,
5255 flush);
5256 if (ret == -ENOSPC &&
5257 unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
5258 struct btrfs_block_rsv *global_rsv =
5259 &root->fs_info->global_block_rsv;
5260
5261 if (block_rsv != global_rsv &&
5262 !block_rsv_use_bytes(global_rsv, orig_bytes))
5263 ret = 0;
5264 }
5265 if (ret == -ENOSPC)
5266 trace_btrfs_space_reservation(root->fs_info,
5267 "space_info:enospc",
5268 block_rsv->space_info->flags,
5269 orig_bytes, 1);
5270 return ret;
5271 }
5272
5273 static struct btrfs_block_rsv *get_block_rsv(
5274 const struct btrfs_trans_handle *trans,
5275 const struct btrfs_root *root)
5276 {
5277 struct btrfs_block_rsv *block_rsv = NULL;
5278
5279 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
5280 (root == root->fs_info->csum_root && trans->adding_csums) ||
5281 (root == root->fs_info->uuid_root))
5282 block_rsv = trans->block_rsv;
5283
5284 if (!block_rsv)
5285 block_rsv = root->block_rsv;
5286
5287 if (!block_rsv)
5288 block_rsv = &root->fs_info->empty_block_rsv;
5289
5290 return block_rsv;
5291 }
5292
5293 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
5294 u64 num_bytes)
5295 {
5296 int ret = -ENOSPC;
5297 spin_lock(&block_rsv->lock);
5298 if (block_rsv->reserved >= num_bytes) {
5299 block_rsv->reserved -= num_bytes;
5300 if (block_rsv->reserved < block_rsv->size)
5301 block_rsv->full = 0;
5302 ret = 0;
5303 }
5304 spin_unlock(&block_rsv->lock);
5305 return ret;
5306 }
5307
5308 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
5309 u64 num_bytes, int update_size)
5310 {
5311 spin_lock(&block_rsv->lock);
5312 block_rsv->reserved += num_bytes;
5313 if (update_size)
5314 block_rsv->size += num_bytes;
5315 else if (block_rsv->reserved >= block_rsv->size)
5316 block_rsv->full = 1;
5317 spin_unlock(&block_rsv->lock);
5318 }
5319
5320 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
5321 struct btrfs_block_rsv *dest, u64 num_bytes,
5322 int min_factor)
5323 {
5324 struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5325 u64 min_bytes;
5326
5327 if (global_rsv->space_info != dest->space_info)
5328 return -ENOSPC;
5329
5330 spin_lock(&global_rsv->lock);
5331 min_bytes = div_factor(global_rsv->size, min_factor);
5332 if (global_rsv->reserved < min_bytes + num_bytes) {
5333 spin_unlock(&global_rsv->lock);
5334 return -ENOSPC;
5335 }
5336 global_rsv->reserved -= num_bytes;
5337 if (global_rsv->reserved < global_rsv->size)
5338 global_rsv->full = 0;
5339 spin_unlock(&global_rsv->lock);
5340
5341 block_rsv_add_bytes(dest, num_bytes, 1);
5342 return 0;
5343 }
5344
5345 /*
5346 * This is for space we already have accounted in space_info->bytes_may_use, so
5347 * basically when we're returning space from block_rsv's.
5348 */
5349 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
5350 struct btrfs_space_info *space_info,
5351 u64 num_bytes)
5352 {
5353 struct reserve_ticket *ticket;
5354 struct list_head *head;
5355 u64 used;
5356 enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_NO_FLUSH;
5357 bool check_overcommit = false;
5358
5359 spin_lock(&space_info->lock);
5360 head = &space_info->priority_tickets;
5361
5362 /*
5363 * If we are over our limit then we need to check and see if we can
5364 * overcommit, and if we can't then we just need to free up our space
5365 * and not satisfy any requests.
5366 */
5367 used = space_info->bytes_used + space_info->bytes_reserved +
5368 space_info->bytes_pinned + space_info->bytes_readonly +
5369 space_info->bytes_may_use;
5370 if (used - num_bytes >= space_info->total_bytes)
5371 check_overcommit = true;
5372 again:
5373 while (!list_empty(head) && num_bytes) {
5374 ticket = list_first_entry(head, struct reserve_ticket,
5375 list);
5376 /*
5377 * We use 0 bytes because this space is already reserved, so
5378 * adding the ticket space would be a double count.
5379 */
5380 if (check_overcommit &&
5381 !can_overcommit(fs_info->extent_root, space_info, 0,
5382 flush))
5383 break;
5384 if (num_bytes >= ticket->bytes) {
5385 list_del_init(&ticket->list);
5386 num_bytes -= ticket->bytes;
5387 ticket->bytes = 0;
5388 space_info->tickets_id++;
5389 wake_up(&ticket->wait);
5390 } else {
5391 ticket->bytes -= num_bytes;
5392 num_bytes = 0;
5393 }
5394 }
5395
5396 if (num_bytes && head == &space_info->priority_tickets) {
5397 head = &space_info->tickets;
5398 flush = BTRFS_RESERVE_FLUSH_ALL;
5399 goto again;
5400 }
5401 space_info->bytes_may_use -= num_bytes;
5402 trace_btrfs_space_reservation(fs_info, "space_info",
5403 space_info->flags, num_bytes, 0);
5404 spin_unlock(&space_info->lock);
5405 }
5406
5407 /*
5408 * This is for newly allocated space that isn't accounted in
5409 * space_info->bytes_may_use yet. So if we allocate a chunk or unpin an extent
5410 * we use this helper.
5411 */
5412 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
5413 struct btrfs_space_info *space_info,
5414 u64 num_bytes)
5415 {
5416 struct reserve_ticket *ticket;
5417 struct list_head *head = &space_info->priority_tickets;
5418
5419 again:
5420 while (!list_empty(head) && num_bytes) {
5421 ticket = list_first_entry(head, struct reserve_ticket,
5422 list);
5423 if (num_bytes >= ticket->bytes) {
5424 trace_btrfs_space_reservation(fs_info, "space_info",
5425 space_info->flags,
5426 ticket->bytes, 1);
5427 list_del_init(&ticket->list);
5428 num_bytes -= ticket->bytes;
5429 space_info->bytes_may_use += ticket->bytes;
5430 ticket->bytes = 0;
5431 space_info->tickets_id++;
5432 wake_up(&ticket->wait);
5433 } else {
5434 trace_btrfs_space_reservation(fs_info, "space_info",
5435 space_info->flags,
5436 num_bytes, 1);
5437 space_info->bytes_may_use += num_bytes;
5438 ticket->bytes -= num_bytes;
5439 num_bytes = 0;
5440 }
5441 }
5442
5443 if (num_bytes && head == &space_info->priority_tickets) {
5444 head = &space_info->tickets;
5445 goto again;
5446 }
5447 }
5448
5449 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
5450 struct btrfs_block_rsv *block_rsv,
5451 struct btrfs_block_rsv *dest, u64 num_bytes)
5452 {
5453 struct btrfs_space_info *space_info = block_rsv->space_info;
5454
5455 spin_lock(&block_rsv->lock);
5456 if (num_bytes == (u64)-1)
5457 num_bytes = block_rsv->size;
5458 block_rsv->size -= num_bytes;
5459 if (block_rsv->reserved >= block_rsv->size) {
5460 num_bytes = block_rsv->reserved - block_rsv->size;
5461 block_rsv->reserved = block_rsv->size;
5462 block_rsv->full = 1;
5463 } else {
5464 num_bytes = 0;
5465 }
5466 spin_unlock(&block_rsv->lock);
5467
5468 if (num_bytes > 0) {
5469 if (dest) {
5470 spin_lock(&dest->lock);
5471 if (!dest->full) {
5472 u64 bytes_to_add;
5473
5474 bytes_to_add = dest->size - dest->reserved;
5475 bytes_to_add = min(num_bytes, bytes_to_add);
5476 dest->reserved += bytes_to_add;
5477 if (dest->reserved >= dest->size)
5478 dest->full = 1;
5479 num_bytes -= bytes_to_add;
5480 }
5481 spin_unlock(&dest->lock);
5482 }
5483 if (num_bytes)
5484 space_info_add_old_bytes(fs_info, space_info,
5485 num_bytes);
5486 }
5487 }
5488
5489 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src,
5490 struct btrfs_block_rsv *dst, u64 num_bytes,
5491 int update_size)
5492 {
5493 int ret;
5494
5495 ret = block_rsv_use_bytes(src, num_bytes);
5496 if (ret)
5497 return ret;
5498
5499 block_rsv_add_bytes(dst, num_bytes, update_size);
5500 return 0;
5501 }
5502
5503 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
5504 {
5505 memset(rsv, 0, sizeof(*rsv));
5506 spin_lock_init(&rsv->lock);
5507 rsv->type = type;
5508 }
5509
5510 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
5511 unsigned short type)
5512 {
5513 struct btrfs_block_rsv *block_rsv;
5514 struct btrfs_fs_info *fs_info = root->fs_info;
5515
5516 block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
5517 if (!block_rsv)
5518 return NULL;
5519
5520 btrfs_init_block_rsv(block_rsv, type);
5521 block_rsv->space_info = __find_space_info(fs_info,
5522 BTRFS_BLOCK_GROUP_METADATA);
5523 return block_rsv;
5524 }
5525
5526 void btrfs_free_block_rsv(struct btrfs_root *root,
5527 struct btrfs_block_rsv *rsv)
5528 {
5529 if (!rsv)
5530 return;
5531 btrfs_block_rsv_release(root, rsv, (u64)-1);
5532 kfree(rsv);
5533 }
5534
5535 void __btrfs_free_block_rsv(struct btrfs_block_rsv *rsv)
5536 {
5537 kfree(rsv);
5538 }
5539
5540 int btrfs_block_rsv_add(struct btrfs_root *root,
5541 struct btrfs_block_rsv *block_rsv, u64 num_bytes,
5542 enum btrfs_reserve_flush_enum flush)
5543 {
5544 int ret;
5545
5546 if (num_bytes == 0)
5547 return 0;
5548
5549 ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5550 if (!ret) {
5551 block_rsv_add_bytes(block_rsv, num_bytes, 1);
5552 return 0;
5553 }
5554
5555 return ret;
5556 }
5557
5558 int btrfs_block_rsv_check(struct btrfs_root *root,
5559 struct btrfs_block_rsv *block_rsv, int min_factor)
5560 {
5561 u64 num_bytes = 0;
5562 int ret = -ENOSPC;
5563
5564 if (!block_rsv)
5565 return 0;
5566
5567 spin_lock(&block_rsv->lock);
5568 num_bytes = div_factor(block_rsv->size, min_factor);
5569 if (block_rsv->reserved >= num_bytes)
5570 ret = 0;
5571 spin_unlock(&block_rsv->lock);
5572
5573 return ret;
5574 }
5575
5576 int btrfs_block_rsv_refill(struct btrfs_root *root,
5577 struct btrfs_block_rsv *block_rsv, u64 min_reserved,
5578 enum btrfs_reserve_flush_enum flush)
5579 {
5580 u64 num_bytes = 0;
5581 int ret = -ENOSPC;
5582
5583 if (!block_rsv)
5584 return 0;
5585
5586 spin_lock(&block_rsv->lock);
5587 num_bytes = min_reserved;
5588 if (block_rsv->reserved >= num_bytes)
5589 ret = 0;
5590 else
5591 num_bytes -= block_rsv->reserved;
5592 spin_unlock(&block_rsv->lock);
5593
5594 if (!ret)
5595 return 0;
5596
5597 ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5598 if (!ret) {
5599 block_rsv_add_bytes(block_rsv, num_bytes, 0);
5600 return 0;
5601 }
5602
5603 return ret;
5604 }
5605
5606 void btrfs_block_rsv_release(struct btrfs_root *root,
5607 struct btrfs_block_rsv *block_rsv,
5608 u64 num_bytes)
5609 {
5610 struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5611 if (global_rsv == block_rsv ||
5612 block_rsv->space_info != global_rsv->space_info)
5613 global_rsv = NULL;
5614 block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
5615 num_bytes);
5616 }
5617
5618 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
5619 {
5620 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
5621 struct btrfs_space_info *sinfo = block_rsv->space_info;
5622 u64 num_bytes;
5623
5624 /*
5625 * The global block rsv is based on the size of the extent tree, the
5626 * checksum tree and the root tree. If the fs is empty we want to set
5627 * it to a minimal amount for safety.
5628 */
5629 num_bytes = btrfs_root_used(&fs_info->extent_root->root_item) +
5630 btrfs_root_used(&fs_info->csum_root->root_item) +
5631 btrfs_root_used(&fs_info->tree_root->root_item);
5632 num_bytes = max_t(u64, num_bytes, SZ_16M);
5633
5634 spin_lock(&sinfo->lock);
5635 spin_lock(&block_rsv->lock);
5636
5637 block_rsv->size = min_t(u64, num_bytes, SZ_512M);
5638
5639 if (block_rsv->reserved < block_rsv->size) {
5640 num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
5641 sinfo->bytes_reserved + sinfo->bytes_readonly +
5642 sinfo->bytes_may_use;
5643 if (sinfo->total_bytes > num_bytes) {
5644 num_bytes = sinfo->total_bytes - num_bytes;
5645 num_bytes = min(num_bytes,
5646 block_rsv->size - block_rsv->reserved);
5647 block_rsv->reserved += num_bytes;
5648 sinfo->bytes_may_use += num_bytes;
5649 trace_btrfs_space_reservation(fs_info, "space_info",
5650 sinfo->flags, num_bytes,
5651 1);
5652 }
5653 } else if (block_rsv->reserved > block_rsv->size) {
5654 num_bytes = block_rsv->reserved - block_rsv->size;
5655 sinfo->bytes_may_use -= num_bytes;
5656 trace_btrfs_space_reservation(fs_info, "space_info",
5657 sinfo->flags, num_bytes, 0);
5658 block_rsv->reserved = block_rsv->size;
5659 }
5660
5661 if (block_rsv->reserved == block_rsv->size)
5662 block_rsv->full = 1;
5663 else
5664 block_rsv->full = 0;
5665
5666 spin_unlock(&block_rsv->lock);
5667 spin_unlock(&sinfo->lock);
5668 }
5669
5670 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
5671 {
5672 struct btrfs_space_info *space_info;
5673
5674 space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
5675 fs_info->chunk_block_rsv.space_info = space_info;
5676
5677 space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5678 fs_info->global_block_rsv.space_info = space_info;
5679 fs_info->delalloc_block_rsv.space_info = space_info;
5680 fs_info->trans_block_rsv.space_info = space_info;
5681 fs_info->empty_block_rsv.space_info = space_info;
5682 fs_info->delayed_block_rsv.space_info = space_info;
5683
5684 fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
5685 fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
5686 fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
5687 fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
5688 if (fs_info->quota_root)
5689 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
5690 fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
5691
5692 update_global_block_rsv(fs_info);
5693 }
5694
5695 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
5696 {
5697 block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
5698 (u64)-1);
5699 WARN_ON(fs_info->delalloc_block_rsv.size > 0);
5700 WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
5701 WARN_ON(fs_info->trans_block_rsv.size > 0);
5702 WARN_ON(fs_info->trans_block_rsv.reserved > 0);
5703 WARN_ON(fs_info->chunk_block_rsv.size > 0);
5704 WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
5705 WARN_ON(fs_info->delayed_block_rsv.size > 0);
5706 WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
5707 }
5708
5709 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
5710 struct btrfs_root *root)
5711 {
5712 if (!trans->block_rsv)
5713 return;
5714
5715 if (!trans->bytes_reserved)
5716 return;
5717
5718 trace_btrfs_space_reservation(root->fs_info, "transaction",
5719 trans->transid, trans->bytes_reserved, 0);
5720 btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
5721 trans->bytes_reserved = 0;
5722 }
5723
5724 /*
5725 * To be called after all the new block groups attached to the transaction
5726 * handle have been created (btrfs_create_pending_block_groups()).
5727 */
5728 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
5729 {
5730 struct btrfs_fs_info *fs_info = trans->fs_info;
5731
5732 if (!trans->chunk_bytes_reserved)
5733 return;
5734
5735 WARN_ON_ONCE(!list_empty(&trans->new_bgs));
5736
5737 block_rsv_release_bytes(fs_info, &fs_info->chunk_block_rsv, NULL,
5738 trans->chunk_bytes_reserved);
5739 trans->chunk_bytes_reserved = 0;
5740 }
5741
5742 /* Can only return 0 or -ENOSPC */
5743 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
5744 struct inode *inode)
5745 {
5746 struct btrfs_root *root = BTRFS_I(inode)->root;
5747 /*
5748 * We always use trans->block_rsv here as we will have reserved space
5749 * for our orphan when starting the transaction, using get_block_rsv()
5750 * here will sometimes make us choose the wrong block rsv as we could be
5751 * doing a reloc inode for a non refcounted root.
5752 */
5753 struct btrfs_block_rsv *src_rsv = trans->block_rsv;
5754 struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
5755
5756 /*
5757 * We need to hold space in order to delete our orphan item once we've
5758 * added it, so this takes the reservation so we can release it later
5759 * when we are truly done with the orphan item.
5760 */
5761 u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5762 trace_btrfs_space_reservation(root->fs_info, "orphan",
5763 btrfs_ino(inode), num_bytes, 1);
5764 return btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes, 1);
5765 }
5766
5767 void btrfs_orphan_release_metadata(struct inode *inode)
5768 {
5769 struct btrfs_root *root = BTRFS_I(inode)->root;
5770 u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5771 trace_btrfs_space_reservation(root->fs_info, "orphan",
5772 btrfs_ino(inode), num_bytes, 0);
5773 btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
5774 }
5775
5776 /*
5777 * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
5778 * root: the root of the parent directory
5779 * rsv: block reservation
5780 * items: the number of items that we need do reservation
5781 * qgroup_reserved: used to return the reserved size in qgroup
5782 *
5783 * This function is used to reserve the space for snapshot/subvolume
5784 * creation and deletion. Those operations are different with the
5785 * common file/directory operations, they change two fs/file trees
5786 * and root tree, the number of items that the qgroup reserves is
5787 * different with the free space reservation. So we can not use
5788 * the space reservation mechanism in start_transaction().
5789 */
5790 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
5791 struct btrfs_block_rsv *rsv,
5792 int items,
5793 u64 *qgroup_reserved,
5794 bool use_global_rsv)
5795 {
5796 u64 num_bytes;
5797 int ret;
5798 struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5799
5800 if (test_bit(BTRFS_FS_QUOTA_ENABLED, &root->fs_info->flags)) {
5801 /* One for parent inode, two for dir entries */
5802 num_bytes = 3 * root->nodesize;
5803 ret = btrfs_qgroup_reserve_meta(root, num_bytes);
5804 if (ret)
5805 return ret;
5806 } else {
5807 num_bytes = 0;
5808 }
5809
5810 *qgroup_reserved = num_bytes;
5811
5812 num_bytes = btrfs_calc_trans_metadata_size(root, items);
5813 rsv->space_info = __find_space_info(root->fs_info,
5814 BTRFS_BLOCK_GROUP_METADATA);
5815 ret = btrfs_block_rsv_add(root, rsv, num_bytes,
5816 BTRFS_RESERVE_FLUSH_ALL);
5817
5818 if (ret == -ENOSPC && use_global_rsv)
5819 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes, 1);
5820
5821 if (ret && *qgroup_reserved)
5822 btrfs_qgroup_free_meta(root, *qgroup_reserved);
5823
5824 return ret;
5825 }
5826
5827 void btrfs_subvolume_release_metadata(struct btrfs_root *root,
5828 struct btrfs_block_rsv *rsv,
5829 u64 qgroup_reserved)
5830 {
5831 btrfs_block_rsv_release(root, rsv, (u64)-1);
5832 }
5833
5834 /**
5835 * drop_outstanding_extent - drop an outstanding extent
5836 * @inode: the inode we're dropping the extent for
5837 * @num_bytes: the number of bytes we're releasing.
5838 *
5839 * This is called when we are freeing up an outstanding extent, either called
5840 * after an error or after an extent is written. This will return the number of
5841 * reserved extents that need to be freed. This must be called with
5842 * BTRFS_I(inode)->lock held.
5843 */
5844 static unsigned drop_outstanding_extent(struct inode *inode, u64 num_bytes)
5845 {
5846 unsigned drop_inode_space = 0;
5847 unsigned dropped_extents = 0;
5848 unsigned num_extents = 0;
5849
5850 num_extents = (unsigned)div64_u64(num_bytes +
5851 BTRFS_MAX_EXTENT_SIZE - 1,
5852 BTRFS_MAX_EXTENT_SIZE);
5853 ASSERT(num_extents);
5854 ASSERT(BTRFS_I(inode)->outstanding_extents >= num_extents);
5855 BTRFS_I(inode)->outstanding_extents -= num_extents;
5856
5857 if (BTRFS_I(inode)->outstanding_extents == 0 &&
5858 test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5859 &BTRFS_I(inode)->runtime_flags))
5860 drop_inode_space = 1;
5861
5862 /*
5863 * If we have more or the same amount of outstanding extents than we have
5864 * reserved then we need to leave the reserved extents count alone.
5865 */
5866 if (BTRFS_I(inode)->outstanding_extents >=
5867 BTRFS_I(inode)->reserved_extents)
5868 return drop_inode_space;
5869
5870 dropped_extents = BTRFS_I(inode)->reserved_extents -
5871 BTRFS_I(inode)->outstanding_extents;
5872 BTRFS_I(inode)->reserved_extents -= dropped_extents;
5873 return dropped_extents + drop_inode_space;
5874 }
5875
5876 /**
5877 * calc_csum_metadata_size - return the amount of metadata space that must be
5878 * reserved/freed for the given bytes.
5879 * @inode: the inode we're manipulating
5880 * @num_bytes: the number of bytes in question
5881 * @reserve: 1 if we are reserving space, 0 if we are freeing space
5882 *
5883 * This adjusts the number of csum_bytes in the inode and then returns the
5884 * correct amount of metadata that must either be reserved or freed. We
5885 * calculate how many checksums we can fit into one leaf and then divide the
5886 * number of bytes that will need to be checksumed by this value to figure out
5887 * how many checksums will be required. If we are adding bytes then the number
5888 * may go up and we will return the number of additional bytes that must be
5889 * reserved. If it is going down we will return the number of bytes that must
5890 * be freed.
5891 *
5892 * This must be called with BTRFS_I(inode)->lock held.
5893 */
5894 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
5895 int reserve)
5896 {
5897 struct btrfs_root *root = BTRFS_I(inode)->root;
5898 u64 old_csums, num_csums;
5899
5900 if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
5901 BTRFS_I(inode)->csum_bytes == 0)
5902 return 0;
5903
5904 old_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5905 if (reserve)
5906 BTRFS_I(inode)->csum_bytes += num_bytes;
5907 else
5908 BTRFS_I(inode)->csum_bytes -= num_bytes;
5909 num_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5910
5911 /* No change, no need to reserve more */
5912 if (old_csums == num_csums)
5913 return 0;
5914
5915 if (reserve)
5916 return btrfs_calc_trans_metadata_size(root,
5917 num_csums - old_csums);
5918
5919 return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
5920 }
5921
5922 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
5923 {
5924 struct btrfs_root *root = BTRFS_I(inode)->root;
5925 struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
5926 u64 to_reserve = 0;
5927 u64 csum_bytes;
5928 unsigned nr_extents = 0;
5929 enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
5930 int ret = 0;
5931 bool delalloc_lock = true;
5932 u64 to_free = 0;
5933 unsigned dropped;
5934 bool release_extra = false;
5935
5936 /* If we are a free space inode we need to not flush since we will be in
5937 * the middle of a transaction commit. We also don't need the delalloc
5938 * mutex since we won't race with anybody. We need this mostly to make
5939 * lockdep shut its filthy mouth.
5940 *
5941 * If we have a transaction open (can happen if we call truncate_block
5942 * from truncate), then we need FLUSH_LIMIT so we don't deadlock.
5943 */
5944 if (btrfs_is_free_space_inode(inode)) {
5945 flush = BTRFS_RESERVE_NO_FLUSH;
5946 delalloc_lock = false;
5947 } else if (current->journal_info) {
5948 flush = BTRFS_RESERVE_FLUSH_LIMIT;
5949 }
5950
5951 if (flush != BTRFS_RESERVE_NO_FLUSH &&
5952 btrfs_transaction_in_commit(root->fs_info))
5953 schedule_timeout(1);
5954
5955 if (delalloc_lock)
5956 mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
5957
5958 num_bytes = ALIGN(num_bytes, root->sectorsize);
5959
5960 spin_lock(&BTRFS_I(inode)->lock);
5961 nr_extents = (unsigned)div64_u64(num_bytes +
5962 BTRFS_MAX_EXTENT_SIZE - 1,
5963 BTRFS_MAX_EXTENT_SIZE);
5964 BTRFS_I(inode)->outstanding_extents += nr_extents;
5965
5966 nr_extents = 0;
5967 if (BTRFS_I(inode)->outstanding_extents >
5968 BTRFS_I(inode)->reserved_extents)
5969 nr_extents += BTRFS_I(inode)->outstanding_extents -
5970 BTRFS_I(inode)->reserved_extents;
5971
5972 /* We always want to reserve a slot for updating the inode. */
5973 to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents + 1);
5974 to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
5975 csum_bytes = BTRFS_I(inode)->csum_bytes;
5976 spin_unlock(&BTRFS_I(inode)->lock);
5977
5978 if (test_bit(BTRFS_FS_QUOTA_ENABLED, &root->fs_info->flags)) {
5979 ret = btrfs_qgroup_reserve_meta(root,
5980 nr_extents * root->nodesize);
5981 if (ret)
5982 goto out_fail;
5983 }
5984
5985 ret = btrfs_block_rsv_add(root, block_rsv, to_reserve, flush);
5986 if (unlikely(ret)) {
5987 btrfs_qgroup_free_meta(root, nr_extents * root->nodesize);
5988 goto out_fail;
5989 }
5990
5991 spin_lock(&BTRFS_I(inode)->lock);
5992 if (test_and_set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5993 &BTRFS_I(inode)->runtime_flags)) {
5994 to_reserve -= btrfs_calc_trans_metadata_size(root, 1);
5995 release_extra = true;
5996 }
5997 BTRFS_I(inode)->reserved_extents += nr_extents;
5998 spin_unlock(&BTRFS_I(inode)->lock);
5999
6000 if (delalloc_lock)
6001 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
6002
6003 if (to_reserve)
6004 trace_btrfs_space_reservation(root->fs_info, "delalloc",
6005 btrfs_ino(inode), to_reserve, 1);
6006 if (release_extra)
6007 btrfs_block_rsv_release(root, block_rsv,
6008 btrfs_calc_trans_metadata_size(root,
6009 1));
6010 return 0;
6011
6012 out_fail:
6013 spin_lock(&BTRFS_I(inode)->lock);
6014 dropped = drop_outstanding_extent(inode, num_bytes);
6015 /*
6016 * If the inodes csum_bytes is the same as the original
6017 * csum_bytes then we know we haven't raced with any free()ers
6018 * so we can just reduce our inodes csum bytes and carry on.
6019 */
6020 if (BTRFS_I(inode)->csum_bytes == csum_bytes) {
6021 calc_csum_metadata_size(inode, num_bytes, 0);
6022 } else {
6023 u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes;
6024 u64 bytes;
6025
6026 /*
6027 * This is tricky, but first we need to figure out how much we
6028 * freed from any free-ers that occurred during this
6029 * reservation, so we reset ->csum_bytes to the csum_bytes
6030 * before we dropped our lock, and then call the free for the
6031 * number of bytes that were freed while we were trying our
6032 * reservation.
6033 */
6034 bytes = csum_bytes - BTRFS_I(inode)->csum_bytes;
6035 BTRFS_I(inode)->csum_bytes = csum_bytes;
6036 to_free = calc_csum_metadata_size(inode, bytes, 0);
6037
6038
6039 /*
6040 * Now we need to see how much we would have freed had we not
6041 * been making this reservation and our ->csum_bytes were not
6042 * artificially inflated.
6043 */
6044 BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes;
6045 bytes = csum_bytes - orig_csum_bytes;
6046 bytes = calc_csum_metadata_size(inode, bytes, 0);
6047
6048 /*
6049 * Now reset ->csum_bytes to what it should be. If bytes is
6050 * more than to_free then we would have freed more space had we
6051 * not had an artificially high ->csum_bytes, so we need to free
6052 * the remainder. If bytes is the same or less then we don't
6053 * need to do anything, the other free-ers did the correct
6054 * thing.
6055 */
6056 BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes;
6057 if (bytes > to_free)
6058 to_free = bytes - to_free;
6059 else
6060 to_free = 0;
6061 }
6062 spin_unlock(&BTRFS_I(inode)->lock);
6063 if (dropped)
6064 to_free += btrfs_calc_trans_metadata_size(root, dropped);
6065
6066 if (to_free) {
6067 btrfs_block_rsv_release(root, block_rsv, to_free);
6068 trace_btrfs_space_reservation(root->fs_info, "delalloc",
6069 btrfs_ino(inode), to_free, 0);
6070 }
6071 if (delalloc_lock)
6072 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
6073 return ret;
6074 }
6075
6076 /**
6077 * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
6078 * @inode: the inode to release the reservation for
6079 * @num_bytes: the number of bytes we're releasing
6080 *
6081 * This will release the metadata reservation for an inode. This can be called
6082 * once we complete IO for a given set of bytes to release their metadata
6083 * reservations.
6084 */
6085 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
6086 {
6087 struct btrfs_root *root = BTRFS_I(inode)->root;
6088 u64 to_free = 0;
6089 unsigned dropped;
6090
6091 num_bytes = ALIGN(num_bytes, root->sectorsize);
6092 spin_lock(&BTRFS_I(inode)->lock);
6093 dropped = drop_outstanding_extent(inode, num_bytes);
6094
6095 if (num_bytes)
6096 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
6097 spin_unlock(&BTRFS_I(inode)->lock);
6098 if (dropped > 0)
6099 to_free += btrfs_calc_trans_metadata_size(root, dropped);
6100
6101 if (btrfs_is_testing(root->fs_info))
6102 return;
6103
6104 trace_btrfs_space_reservation(root->fs_info, "delalloc",
6105 btrfs_ino(inode), to_free, 0);
6106
6107 btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
6108 to_free);
6109 }
6110
6111 /**
6112 * btrfs_delalloc_reserve_space - reserve data and metadata space for
6113 * delalloc
6114 * @inode: inode we're writing to
6115 * @start: start range we are writing to
6116 * @len: how long the range we are writing to
6117 *
6118 * This will do the following things
6119 *
6120 * o reserve space in data space info for num bytes
6121 * and reserve precious corresponding qgroup space
6122 * (Done in check_data_free_space)
6123 *
6124 * o reserve space for metadata space, based on the number of outstanding
6125 * extents and how much csums will be needed
6126 * also reserve metadata space in a per root over-reserve method.
6127 * o add to the inodes->delalloc_bytes
6128 * o add it to the fs_info's delalloc inodes list.
6129 * (Above 3 all done in delalloc_reserve_metadata)
6130 *
6131 * Return 0 for success
6132 * Return <0 for error(-ENOSPC or -EQUOT)
6133 */
6134 int btrfs_delalloc_reserve_space(struct inode *inode, u64 start, u64 len)
6135 {
6136 int ret;
6137
6138 ret = btrfs_check_data_free_space(inode, start, len);
6139 if (ret < 0)
6140 return ret;
6141 ret = btrfs_delalloc_reserve_metadata(inode, len);
6142 if (ret < 0)
6143 btrfs_free_reserved_data_space(inode, start, len);
6144 return ret;
6145 }
6146
6147 /**
6148 * btrfs_delalloc_release_space - release data and metadata space for delalloc
6149 * @inode: inode we're releasing space for
6150 * @start: start position of the space already reserved
6151 * @len: the len of the space already reserved
6152 *
6153 * This must be matched with a call to btrfs_delalloc_reserve_space. This is
6154 * called in the case that we don't need the metadata AND data reservations
6155 * anymore. So if there is an error or we insert an inline extent.
6156 *
6157 * This function will release the metadata space that was not used and will
6158 * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
6159 * list if there are no delalloc bytes left.
6160 * Also it will handle the qgroup reserved space.
6161 */
6162 void btrfs_delalloc_release_space(struct inode *inode, u64 start, u64 len)
6163 {
6164 btrfs_delalloc_release_metadata(inode, len);
6165 btrfs_free_reserved_data_space(inode, start, len);
6166 }
6167
6168 static int update_block_group(struct btrfs_trans_handle *trans,
6169 struct btrfs_root *root, u64 bytenr,
6170 u64 num_bytes, int alloc)
6171 {
6172 struct btrfs_block_group_cache *cache = NULL;
6173 struct btrfs_fs_info *info = root->fs_info;
6174 u64 total = num_bytes;
6175 u64 old_val;
6176 u64 byte_in_group;
6177 int factor;
6178
6179 /* block accounting for super block */
6180 spin_lock(&info->delalloc_root_lock);
6181 old_val = btrfs_super_bytes_used(info->super_copy);
6182 if (alloc)
6183 old_val += num_bytes;
6184 else
6185 old_val -= num_bytes;
6186 btrfs_set_super_bytes_used(info->super_copy, old_val);
6187 spin_unlock(&info->delalloc_root_lock);
6188
6189 while (total) {
6190 cache = btrfs_lookup_block_group(info, bytenr);
6191 if (!cache)
6192 return -ENOENT;
6193 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
6194 BTRFS_BLOCK_GROUP_RAID1 |
6195 BTRFS_BLOCK_GROUP_RAID10))
6196 factor = 2;
6197 else
6198 factor = 1;
6199 /*
6200 * If this block group has free space cache written out, we
6201 * need to make sure to load it if we are removing space. This
6202 * is because we need the unpinning stage to actually add the
6203 * space back to the block group, otherwise we will leak space.
6204 */
6205 if (!alloc && cache->cached == BTRFS_CACHE_NO)
6206 cache_block_group(cache, 1);
6207
6208 byte_in_group = bytenr - cache->key.objectid;
6209 WARN_ON(byte_in_group > cache->key.offset);
6210
6211 spin_lock(&cache->space_info->lock);
6212 spin_lock(&cache->lock);
6213
6214 if (btrfs_test_opt(root->fs_info, SPACE_CACHE) &&
6215 cache->disk_cache_state < BTRFS_DC_CLEAR)
6216 cache->disk_cache_state = BTRFS_DC_CLEAR;
6217
6218 old_val = btrfs_block_group_used(&cache->item);
6219 num_bytes = min(total, cache->key.offset - byte_in_group);
6220 if (alloc) {
6221 old_val += num_bytes;
6222 btrfs_set_block_group_used(&cache->item, old_val);
6223 cache->reserved -= num_bytes;
6224 cache->space_info->bytes_reserved -= num_bytes;
6225 cache->space_info->bytes_used += num_bytes;
6226 cache->space_info->disk_used += num_bytes * factor;
6227 spin_unlock(&cache->lock);
6228 spin_unlock(&cache->space_info->lock);
6229 } else {
6230 old_val -= num_bytes;
6231 btrfs_set_block_group_used(&cache->item, old_val);
6232 cache->pinned += num_bytes;
6233 cache->space_info->bytes_pinned += num_bytes;
6234 cache->space_info->bytes_used -= num_bytes;
6235 cache->space_info->disk_used -= num_bytes * factor;
6236 spin_unlock(&cache->lock);
6237 spin_unlock(&cache->space_info->lock);
6238
6239 trace_btrfs_space_reservation(root->fs_info, "pinned",
6240 cache->space_info->flags,
6241 num_bytes, 1);
6242 set_extent_dirty(info->pinned_extents,
6243 bytenr, bytenr + num_bytes - 1,
6244 GFP_NOFS | __GFP_NOFAIL);
6245 }
6246
6247 spin_lock(&trans->transaction->dirty_bgs_lock);
6248 if (list_empty(&cache->dirty_list)) {
6249 list_add_tail(&cache->dirty_list,
6250 &trans->transaction->dirty_bgs);
6251 trans->transaction->num_dirty_bgs++;
6252 btrfs_get_block_group(cache);
6253 }
6254 spin_unlock(&trans->transaction->dirty_bgs_lock);
6255
6256 /*
6257 * No longer have used bytes in this block group, queue it for
6258 * deletion. We do this after adding the block group to the
6259 * dirty list to avoid races between cleaner kthread and space
6260 * cache writeout.
6261 */
6262 if (!alloc && old_val == 0) {
6263 spin_lock(&info->unused_bgs_lock);
6264 if (list_empty(&cache->bg_list)) {
6265 btrfs_get_block_group(cache);
6266 list_add_tail(&cache->bg_list,
6267 &info->unused_bgs);
6268 }
6269 spin_unlock(&info->unused_bgs_lock);
6270 }
6271
6272 btrfs_put_block_group(cache);
6273 total -= num_bytes;
6274 bytenr += num_bytes;
6275 }
6276 return 0;
6277 }
6278
6279 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
6280 {
6281 struct btrfs_block_group_cache *cache;
6282 u64 bytenr;
6283
6284 spin_lock(&root->fs_info->block_group_cache_lock);
6285 bytenr = root->fs_info->first_logical_byte;
6286 spin_unlock(&root->fs_info->block_group_cache_lock);
6287
6288 if (bytenr < (u64)-1)
6289 return bytenr;
6290
6291 cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
6292 if (!cache)
6293 return 0;
6294
6295 bytenr = cache->key.objectid;
6296 btrfs_put_block_group(cache);
6297
6298 return bytenr;
6299 }
6300
6301 static int pin_down_extent(struct btrfs_root *root,
6302 struct btrfs_block_group_cache *cache,
6303 u64 bytenr, u64 num_bytes, int reserved)
6304 {
6305 spin_lock(&cache->space_info->lock);
6306 spin_lock(&cache->lock);
6307 cache->pinned += num_bytes;
6308 cache->space_info->bytes_pinned += num_bytes;
6309 if (reserved) {
6310 cache->reserved -= num_bytes;
6311 cache->space_info->bytes_reserved -= num_bytes;
6312 }
6313 spin_unlock(&cache->lock);
6314 spin_unlock(&cache->space_info->lock);
6315
6316 trace_btrfs_space_reservation(root->fs_info, "pinned",
6317 cache->space_info->flags, num_bytes, 1);
6318 set_extent_dirty(root->fs_info->pinned_extents, bytenr,
6319 bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
6320 return 0;
6321 }
6322
6323 /*
6324 * this function must be called within transaction
6325 */
6326 int btrfs_pin_extent(struct btrfs_root *root,
6327 u64 bytenr, u64 num_bytes, int reserved)
6328 {
6329 struct btrfs_block_group_cache *cache;
6330
6331 cache = btrfs_lookup_block_group(root->fs_info, bytenr);
6332 BUG_ON(!cache); /* Logic error */
6333
6334 pin_down_extent(root, cache, bytenr, num_bytes, reserved);
6335
6336 btrfs_put_block_group(cache);
6337 return 0;
6338 }
6339
6340 /*
6341 * this function must be called within transaction
6342 */
6343 int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
6344 u64 bytenr, u64 num_bytes)
6345 {
6346 struct btrfs_block_group_cache *cache;
6347 int ret;
6348
6349 cache = btrfs_lookup_block_group(root->fs_info, bytenr);
6350 if (!cache)
6351 return -EINVAL;
6352
6353 /*
6354 * pull in the free space cache (if any) so that our pin
6355 * removes the free space from the cache. We have load_only set
6356 * to one because the slow code to read in the free extents does check
6357 * the pinned extents.
6358 */
6359 cache_block_group(cache, 1);
6360
6361 pin_down_extent(root, cache, bytenr, num_bytes, 0);
6362
6363 /* remove us from the free space cache (if we're there at all) */
6364 ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
6365 btrfs_put_block_group(cache);
6366 return ret;
6367 }
6368
6369 static int __exclude_logged_extent(struct btrfs_root *root, u64 start, u64 num_bytes)
6370 {
6371 int ret;
6372 struct btrfs_block_group_cache *block_group;
6373 struct btrfs_caching_control *caching_ctl;
6374
6375 block_group = btrfs_lookup_block_group(root->fs_info, start);
6376 if (!block_group)
6377 return -EINVAL;
6378
6379 cache_block_group(block_group, 0);
6380 caching_ctl = get_caching_control(block_group);
6381
6382 if (!caching_ctl) {
6383 /* Logic error */
6384 BUG_ON(!block_group_cache_done(block_group));
6385 ret = btrfs_remove_free_space(block_group, start, num_bytes);
6386 } else {
6387 mutex_lock(&caching_ctl->mutex);
6388
6389 if (start >= caching_ctl->progress) {
6390 ret = add_excluded_extent(root, start, num_bytes);
6391 } else if (start + num_bytes <= caching_ctl->progress) {
6392 ret = btrfs_remove_free_space(block_group,
6393 start, num_bytes);
6394 } else {
6395 num_bytes = caching_ctl->progress - start;
6396 ret = btrfs_remove_free_space(block_group,
6397 start, num_bytes);
6398 if (ret)
6399 goto out_lock;
6400
6401 num_bytes = (start + num_bytes) -
6402 caching_ctl->progress;
6403 start = caching_ctl->progress;
6404 ret = add_excluded_extent(root, start, num_bytes);
6405 }
6406 out_lock:
6407 mutex_unlock(&caching_ctl->mutex);
6408 put_caching_control(caching_ctl);
6409 }
6410 btrfs_put_block_group(block_group);
6411 return ret;
6412 }
6413
6414 int btrfs_exclude_logged_extents(struct btrfs_root *log,
6415 struct extent_buffer *eb)
6416 {
6417 struct btrfs_file_extent_item *item;
6418 struct btrfs_key key;
6419 int found_type;
6420 int i;
6421
6422 if (!btrfs_fs_incompat(log->fs_info, MIXED_GROUPS))
6423 return 0;
6424
6425 for (i = 0; i < btrfs_header_nritems(eb); i++) {
6426 btrfs_item_key_to_cpu(eb, &key, i);
6427 if (key.type != BTRFS_EXTENT_DATA_KEY)
6428 continue;
6429 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
6430 found_type = btrfs_file_extent_type(eb, item);
6431 if (found_type == BTRFS_FILE_EXTENT_INLINE)
6432 continue;
6433 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
6434 continue;
6435 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
6436 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
6437 __exclude_logged_extent(log, key.objectid, key.offset);
6438 }
6439
6440 return 0;
6441 }
6442
6443 static void
6444 btrfs_inc_block_group_reservations(struct btrfs_block_group_cache *bg)
6445 {
6446 atomic_inc(&bg->reservations);
6447 }
6448
6449 void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
6450 const u64 start)
6451 {
6452 struct btrfs_block_group_cache *bg;
6453
6454 bg = btrfs_lookup_block_group(fs_info, start);
6455 ASSERT(bg);
6456 if (atomic_dec_and_test(&bg->reservations))
6457 wake_up_atomic_t(&bg->reservations);
6458 btrfs_put_block_group(bg);
6459 }
6460
6461 static int btrfs_wait_bg_reservations_atomic_t(atomic_t *a)
6462 {
6463 schedule();
6464 return 0;
6465 }
6466
6467 void btrfs_wait_block_group_reservations(struct btrfs_block_group_cache *bg)
6468 {
6469 struct btrfs_space_info *space_info = bg->space_info;
6470
6471 ASSERT(bg->ro);
6472
6473 if (!(bg->flags & BTRFS_BLOCK_GROUP_DATA))
6474 return;
6475
6476 /*
6477 * Our block group is read only but before we set it to read only,
6478 * some task might have had allocated an extent from it already, but it
6479 * has not yet created a respective ordered extent (and added it to a
6480 * root's list of ordered extents).
6481 * Therefore wait for any task currently allocating extents, since the
6482 * block group's reservations counter is incremented while a read lock
6483 * on the groups' semaphore is held and decremented after releasing
6484 * the read access on that semaphore and creating the ordered extent.
6485 */
6486 down_write(&space_info->groups_sem);
6487 up_write(&space_info->groups_sem);
6488
6489 wait_on_atomic_t(&bg->reservations,
6490 btrfs_wait_bg_reservations_atomic_t,
6491 TASK_UNINTERRUPTIBLE);
6492 }
6493
6494 /**
6495 * btrfs_add_reserved_bytes - update the block_group and space info counters
6496 * @cache: The cache we are manipulating
6497 * @ram_bytes: The number of bytes of file content, and will be same to
6498 * @num_bytes except for the compress path.
6499 * @num_bytes: The number of bytes in question
6500 * @delalloc: The blocks are allocated for the delalloc write
6501 *
6502 * This is called by the allocator when it reserves space. Metadata
6503 * reservations should be called with RESERVE_ALLOC so we do the proper
6504 * ENOSPC accounting. For data we handle the reservation through clearing the
6505 * delalloc bits in the io_tree. We have to do this since we could end up
6506 * allocating less disk space for the amount of data we have reserved in the
6507 * case of compression.
6508 *
6509 * If this is a reservation and the block group has become read only we cannot
6510 * make the reservation and return -EAGAIN, otherwise this function always
6511 * succeeds.
6512 */
6513 static int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
6514 u64 ram_bytes, u64 num_bytes, int delalloc)
6515 {
6516 struct btrfs_space_info *space_info = cache->space_info;
6517 int ret = 0;
6518
6519 spin_lock(&space_info->lock);
6520 spin_lock(&cache->lock);
6521 if (cache->ro) {
6522 ret = -EAGAIN;
6523 } else {
6524 cache->reserved += num_bytes;
6525 space_info->bytes_reserved += num_bytes;
6526
6527 trace_btrfs_space_reservation(cache->fs_info,
6528 "space_info", space_info->flags,
6529 ram_bytes, 0);
6530 space_info->bytes_may_use -= ram_bytes;
6531 if (delalloc)
6532 cache->delalloc_bytes += num_bytes;
6533 }
6534 spin_unlock(&cache->lock);
6535 spin_unlock(&space_info->lock);
6536 return ret;
6537 }
6538
6539 /**
6540 * btrfs_free_reserved_bytes - update the block_group and space info counters
6541 * @cache: The cache we are manipulating
6542 * @num_bytes: The number of bytes in question
6543 * @delalloc: The blocks are allocated for the delalloc write
6544 *
6545 * This is called by somebody who is freeing space that was never actually used
6546 * on disk. For example if you reserve some space for a new leaf in transaction
6547 * A and before transaction A commits you free that leaf, you call this with
6548 * reserve set to 0 in order to clear the reservation.
6549 */
6550
6551 static int btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
6552 u64 num_bytes, int delalloc)
6553 {
6554 struct btrfs_space_info *space_info = cache->space_info;
6555 int ret = 0;
6556
6557 spin_lock(&space_info->lock);
6558 spin_lock(&cache->lock);
6559 if (cache->ro)
6560 space_info->bytes_readonly += num_bytes;
6561 cache->reserved -= num_bytes;
6562 space_info->bytes_reserved -= num_bytes;
6563
6564 if (delalloc)
6565 cache->delalloc_bytes -= num_bytes;
6566 spin_unlock(&cache->lock);
6567 spin_unlock(&space_info->lock);
6568 return ret;
6569 }
6570 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
6571 struct btrfs_root *root)
6572 {
6573 struct btrfs_fs_info *fs_info = root->fs_info;
6574 struct btrfs_caching_control *next;
6575 struct btrfs_caching_control *caching_ctl;
6576 struct btrfs_block_group_cache *cache;
6577
6578 down_write(&fs_info->commit_root_sem);
6579
6580 list_for_each_entry_safe(caching_ctl, next,
6581 &fs_info->caching_block_groups, list) {
6582 cache = caching_ctl->block_group;
6583 if (block_group_cache_done(cache)) {
6584 cache->last_byte_to_unpin = (u64)-1;
6585 list_del_init(&caching_ctl->list);
6586 put_caching_control(caching_ctl);
6587 } else {
6588 cache->last_byte_to_unpin = caching_ctl->progress;
6589 }
6590 }
6591
6592 if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6593 fs_info->pinned_extents = &fs_info->freed_extents[1];
6594 else
6595 fs_info->pinned_extents = &fs_info->freed_extents[0];
6596
6597 up_write(&fs_info->commit_root_sem);
6598
6599 update_global_block_rsv(fs_info);
6600 }
6601
6602 /*
6603 * Returns the free cluster for the given space info and sets empty_cluster to
6604 * what it should be based on the mount options.
6605 */
6606 static struct btrfs_free_cluster *
6607 fetch_cluster_info(struct btrfs_root *root, struct btrfs_space_info *space_info,
6608 u64 *empty_cluster)
6609 {
6610 struct btrfs_free_cluster *ret = NULL;
6611 bool ssd = btrfs_test_opt(root->fs_info, SSD);
6612
6613 *empty_cluster = 0;
6614 if (btrfs_mixed_space_info(space_info))
6615 return ret;
6616
6617 if (ssd)
6618 *empty_cluster = SZ_2M;
6619 if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
6620 ret = &root->fs_info->meta_alloc_cluster;
6621 if (!ssd)
6622 *empty_cluster = SZ_64K;
6623 } else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) && ssd) {
6624 ret = &root->fs_info->data_alloc_cluster;
6625 }
6626
6627 return ret;
6628 }
6629
6630 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end,
6631 const bool return_free_space)
6632 {
6633 struct btrfs_fs_info *fs_info = root->fs_info;
6634 struct btrfs_block_group_cache *cache = NULL;
6635 struct btrfs_space_info *space_info;
6636 struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
6637 struct btrfs_free_cluster *cluster = NULL;
6638 u64 len;
6639 u64 total_unpinned = 0;
6640 u64 empty_cluster = 0;
6641 bool readonly;
6642
6643 while (start <= end) {
6644 readonly = false;
6645 if (!cache ||
6646 start >= cache->key.objectid + cache->key.offset) {
6647 if (cache)
6648 btrfs_put_block_group(cache);
6649 total_unpinned = 0;
6650 cache = btrfs_lookup_block_group(fs_info, start);
6651 BUG_ON(!cache); /* Logic error */
6652
6653 cluster = fetch_cluster_info(root,
6654 cache->space_info,
6655 &empty_cluster);
6656 empty_cluster <<= 1;
6657 }
6658
6659 len = cache->key.objectid + cache->key.offset - start;
6660 len = min(len, end + 1 - start);
6661
6662 if (start < cache->last_byte_to_unpin) {
6663 len = min(len, cache->last_byte_to_unpin - start);
6664 if (return_free_space)
6665 btrfs_add_free_space(cache, start, len);
6666 }
6667
6668 start += len;
6669 total_unpinned += len;
6670 space_info = cache->space_info;
6671
6672 /*
6673 * If this space cluster has been marked as fragmented and we've
6674 * unpinned enough in this block group to potentially allow a
6675 * cluster to be created inside of it go ahead and clear the
6676 * fragmented check.
6677 */
6678 if (cluster && cluster->fragmented &&
6679 total_unpinned > empty_cluster) {
6680 spin_lock(&cluster->lock);
6681 cluster->fragmented = 0;
6682 spin_unlock(&cluster->lock);
6683 }
6684
6685 spin_lock(&space_info->lock);
6686 spin_lock(&cache->lock);
6687 cache->pinned -= len;
6688 space_info->bytes_pinned -= len;
6689
6690 trace_btrfs_space_reservation(fs_info, "pinned",
6691 space_info->flags, len, 0);
6692 space_info->max_extent_size = 0;
6693 percpu_counter_add(&space_info->total_bytes_pinned, -len);
6694 if (cache->ro) {
6695 space_info->bytes_readonly += len;
6696 readonly = true;
6697 }
6698 spin_unlock(&cache->lock);
6699 if (!readonly && return_free_space &&
6700 global_rsv->space_info == space_info) {
6701 u64 to_add = len;
6702 WARN_ON(!return_free_space);
6703 spin_lock(&global_rsv->lock);
6704 if (!global_rsv->full) {
6705 to_add = min(len, global_rsv->size -
6706 global_rsv->reserved);
6707 global_rsv->reserved += to_add;
6708 space_info->bytes_may_use += to_add;
6709 if (global_rsv->reserved >= global_rsv->size)
6710 global_rsv->full = 1;
6711 trace_btrfs_space_reservation(fs_info,
6712 "space_info",
6713 space_info->flags,
6714 to_add, 1);
6715 len -= to_add;
6716 }
6717 spin_unlock(&global_rsv->lock);
6718 /* Add to any tickets we may have */
6719 if (len)
6720 space_info_add_new_bytes(fs_info, space_info,
6721 len);
6722 }
6723 spin_unlock(&space_info->lock);
6724 }
6725
6726 if (cache)
6727 btrfs_put_block_group(cache);
6728 return 0;
6729 }
6730
6731 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
6732 struct btrfs_root *root)
6733 {
6734 struct btrfs_fs_info *fs_info = root->fs_info;
6735 struct btrfs_block_group_cache *block_group, *tmp;
6736 struct list_head *deleted_bgs;
6737 struct extent_io_tree *unpin;
6738 u64 start;
6739 u64 end;
6740 int ret;
6741
6742 if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6743 unpin = &fs_info->freed_extents[1];
6744 else
6745 unpin = &fs_info->freed_extents[0];
6746
6747 while (!trans->aborted) {
6748 mutex_lock(&fs_info->unused_bg_unpin_mutex);
6749 ret = find_first_extent_bit(unpin, 0, &start, &end,
6750 EXTENT_DIRTY, NULL);
6751 if (ret) {
6752 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6753 break;
6754 }
6755
6756 if (btrfs_test_opt(root->fs_info, DISCARD))
6757 ret = btrfs_discard_extent(root, start,
6758 end + 1 - start, NULL);
6759
6760 clear_extent_dirty(unpin, start, end);
6761 unpin_extent_range(root, start, end, true);
6762 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6763 cond_resched();
6764 }
6765
6766 /*
6767 * Transaction is finished. We don't need the lock anymore. We
6768 * do need to clean up the block groups in case of a transaction
6769 * abort.
6770 */
6771 deleted_bgs = &trans->transaction->deleted_bgs;
6772 list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
6773 u64 trimmed = 0;
6774
6775 ret = -EROFS;
6776 if (!trans->aborted)
6777 ret = btrfs_discard_extent(root,
6778 block_group->key.objectid,
6779 block_group->key.offset,
6780 &trimmed);
6781
6782 list_del_init(&block_group->bg_list);
6783 btrfs_put_block_group_trimming(block_group);
6784 btrfs_put_block_group(block_group);
6785
6786 if (ret) {
6787 const char *errstr = btrfs_decode_error(ret);
6788 btrfs_warn(fs_info,
6789 "Discard failed while removing blockgroup: errno=%d %s\n",
6790 ret, errstr);
6791 }
6792 }
6793
6794 return 0;
6795 }
6796
6797 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, u64 num_bytes,
6798 u64 owner, u64 root_objectid)
6799 {
6800 struct btrfs_space_info *space_info;
6801 u64 flags;
6802
6803 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6804 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
6805 flags = BTRFS_BLOCK_GROUP_SYSTEM;
6806 else
6807 flags = BTRFS_BLOCK_GROUP_METADATA;
6808 } else {
6809 flags = BTRFS_BLOCK_GROUP_DATA;
6810 }
6811
6812 space_info = __find_space_info(fs_info, flags);
6813 BUG_ON(!space_info); /* Logic bug */
6814 percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
6815 }
6816
6817
6818 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
6819 struct btrfs_root *root,
6820 struct btrfs_delayed_ref_node *node, u64 parent,
6821 u64 root_objectid, u64 owner_objectid,
6822 u64 owner_offset, int refs_to_drop,
6823 struct btrfs_delayed_extent_op *extent_op)
6824 {
6825 struct btrfs_key key;
6826 struct btrfs_path *path;
6827 struct btrfs_fs_info *info = root->fs_info;
6828 struct btrfs_root *extent_root = info->extent_root;
6829 struct extent_buffer *leaf;
6830 struct btrfs_extent_item *ei;
6831 struct btrfs_extent_inline_ref *iref;
6832 int ret;
6833 int is_data;
6834 int extent_slot = 0;
6835 int found_extent = 0;
6836 int num_to_del = 1;
6837 u32 item_size;
6838 u64 refs;
6839 u64 bytenr = node->bytenr;
6840 u64 num_bytes = node->num_bytes;
6841 int last_ref = 0;
6842 bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6843 SKINNY_METADATA);
6844
6845 path = btrfs_alloc_path();
6846 if (!path)
6847 return -ENOMEM;
6848
6849 path->reada = READA_FORWARD;
6850 path->leave_spinning = 1;
6851
6852 is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
6853 BUG_ON(!is_data && refs_to_drop != 1);
6854
6855 if (is_data)
6856 skinny_metadata = 0;
6857
6858 ret = lookup_extent_backref(trans, extent_root, path, &iref,
6859 bytenr, num_bytes, parent,
6860 root_objectid, owner_objectid,
6861 owner_offset);
6862 if (ret == 0) {
6863 extent_slot = path->slots[0];
6864 while (extent_slot >= 0) {
6865 btrfs_item_key_to_cpu(path->nodes[0], &key,
6866 extent_slot);
6867 if (key.objectid != bytenr)
6868 break;
6869 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
6870 key.offset == num_bytes) {
6871 found_extent = 1;
6872 break;
6873 }
6874 if (key.type == BTRFS_METADATA_ITEM_KEY &&
6875 key.offset == owner_objectid) {
6876 found_extent = 1;
6877 break;
6878 }
6879 if (path->slots[0] - extent_slot > 5)
6880 break;
6881 extent_slot--;
6882 }
6883 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6884 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
6885 if (found_extent && item_size < sizeof(*ei))
6886 found_extent = 0;
6887 #endif
6888 if (!found_extent) {
6889 BUG_ON(iref);
6890 ret = remove_extent_backref(trans, extent_root, path,
6891 NULL, refs_to_drop,
6892 is_data, &last_ref);
6893 if (ret) {
6894 btrfs_abort_transaction(trans, ret);
6895 goto out;
6896 }
6897 btrfs_release_path(path);
6898 path->leave_spinning = 1;
6899
6900 key.objectid = bytenr;
6901 key.type = BTRFS_EXTENT_ITEM_KEY;
6902 key.offset = num_bytes;
6903
6904 if (!is_data && skinny_metadata) {
6905 key.type = BTRFS_METADATA_ITEM_KEY;
6906 key.offset = owner_objectid;
6907 }
6908
6909 ret = btrfs_search_slot(trans, extent_root,
6910 &key, path, -1, 1);
6911 if (ret > 0 && skinny_metadata && path->slots[0]) {
6912 /*
6913 * Couldn't find our skinny metadata item,
6914 * see if we have ye olde extent item.
6915 */
6916 path->slots[0]--;
6917 btrfs_item_key_to_cpu(path->nodes[0], &key,
6918 path->slots[0]);
6919 if (key.objectid == bytenr &&
6920 key.type == BTRFS_EXTENT_ITEM_KEY &&
6921 key.offset == num_bytes)
6922 ret = 0;
6923 }
6924
6925 if (ret > 0 && skinny_metadata) {
6926 skinny_metadata = false;
6927 key.objectid = bytenr;
6928 key.type = BTRFS_EXTENT_ITEM_KEY;
6929 key.offset = num_bytes;
6930 btrfs_release_path(path);
6931 ret = btrfs_search_slot(trans, extent_root,
6932 &key, path, -1, 1);
6933 }
6934
6935 if (ret) {
6936 btrfs_err(info,
6937 "umm, got %d back from search, was looking for %llu",
6938 ret, bytenr);
6939 if (ret > 0)
6940 btrfs_print_leaf(extent_root,
6941 path->nodes[0]);
6942 }
6943 if (ret < 0) {
6944 btrfs_abort_transaction(trans, ret);
6945 goto out;
6946 }
6947 extent_slot = path->slots[0];
6948 }
6949 } else if (WARN_ON(ret == -ENOENT)) {
6950 btrfs_print_leaf(extent_root, path->nodes[0]);
6951 btrfs_err(info,
6952 "unable to find ref byte nr %llu parent %llu root %llu owner %llu offset %llu",
6953 bytenr, parent, root_objectid, owner_objectid,
6954 owner_offset);
6955 btrfs_abort_transaction(trans, ret);
6956 goto out;
6957 } else {
6958 btrfs_abort_transaction(trans, ret);
6959 goto out;
6960 }
6961
6962 leaf = path->nodes[0];
6963 item_size = btrfs_item_size_nr(leaf, extent_slot);
6964 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6965 if (item_size < sizeof(*ei)) {
6966 BUG_ON(found_extent || extent_slot != path->slots[0]);
6967 ret = convert_extent_item_v0(trans, extent_root, path,
6968 owner_objectid, 0);
6969 if (ret < 0) {
6970 btrfs_abort_transaction(trans, ret);
6971 goto out;
6972 }
6973
6974 btrfs_release_path(path);
6975 path->leave_spinning = 1;
6976
6977 key.objectid = bytenr;
6978 key.type = BTRFS_EXTENT_ITEM_KEY;
6979 key.offset = num_bytes;
6980
6981 ret = btrfs_search_slot(trans, extent_root, &key, path,
6982 -1, 1);
6983 if (ret) {
6984 btrfs_err(info,
6985 "umm, got %d back from search, was looking for %llu",
6986 ret, bytenr);
6987 btrfs_print_leaf(extent_root, path->nodes[0]);
6988 }
6989 if (ret < 0) {
6990 btrfs_abort_transaction(trans, ret);
6991 goto out;
6992 }
6993
6994 extent_slot = path->slots[0];
6995 leaf = path->nodes[0];
6996 item_size = btrfs_item_size_nr(leaf, extent_slot);
6997 }
6998 #endif
6999 BUG_ON(item_size < sizeof(*ei));
7000 ei = btrfs_item_ptr(leaf, extent_slot,
7001 struct btrfs_extent_item);
7002 if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
7003 key.type == BTRFS_EXTENT_ITEM_KEY) {
7004 struct btrfs_tree_block_info *bi;
7005 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
7006 bi = (struct btrfs_tree_block_info *)(ei + 1);
7007 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
7008 }
7009
7010 refs = btrfs_extent_refs(leaf, ei);
7011 if (refs < refs_to_drop) {
7012 btrfs_err(info,
7013 "trying to drop %d refs but we only have %Lu for bytenr %Lu",
7014 refs_to_drop, refs, bytenr);
7015 ret = -EINVAL;
7016 btrfs_abort_transaction(trans, ret);
7017 goto out;
7018 }
7019 refs -= refs_to_drop;
7020
7021 if (refs > 0) {
7022 if (extent_op)
7023 __run_delayed_extent_op(extent_op, leaf, ei);
7024 /*
7025 * In the case of inline back ref, reference count will
7026 * be updated by remove_extent_backref
7027 */
7028 if (iref) {
7029 BUG_ON(!found_extent);
7030 } else {
7031 btrfs_set_extent_refs(leaf, ei, refs);
7032 btrfs_mark_buffer_dirty(leaf);
7033 }
7034 if (found_extent) {
7035 ret = remove_extent_backref(trans, extent_root, path,
7036 iref, refs_to_drop,
7037 is_data, &last_ref);
7038 if (ret) {
7039 btrfs_abort_transaction(trans, ret);
7040 goto out;
7041 }
7042 }
7043 add_pinned_bytes(root->fs_info, -num_bytes, owner_objectid,
7044 root_objectid);
7045 } else {
7046 if (found_extent) {
7047 BUG_ON(is_data && refs_to_drop !=
7048 extent_data_ref_count(path, iref));
7049 if (iref) {
7050 BUG_ON(path->slots[0] != extent_slot);
7051 } else {
7052 BUG_ON(path->slots[0] != extent_slot + 1);
7053 path->slots[0] = extent_slot;
7054 num_to_del = 2;
7055 }
7056 }
7057
7058 last_ref = 1;
7059 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
7060 num_to_del);
7061 if (ret) {
7062 btrfs_abort_transaction(trans, ret);
7063 goto out;
7064 }
7065 btrfs_release_path(path);
7066
7067 if (is_data) {
7068 ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
7069 if (ret) {
7070 btrfs_abort_transaction(trans, ret);
7071 goto out;
7072 }
7073 }
7074
7075 ret = add_to_free_space_tree(trans, root->fs_info, bytenr,
7076 num_bytes);
7077 if (ret) {
7078 btrfs_abort_transaction(trans, ret);
7079 goto out;
7080 }
7081
7082 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
7083 if (ret) {
7084 btrfs_abort_transaction(trans, ret);
7085 goto out;
7086 }
7087 }
7088 btrfs_release_path(path);
7089
7090 out:
7091 btrfs_free_path(path);
7092 return ret;
7093 }
7094
7095 /*
7096 * when we free an block, it is possible (and likely) that we free the last
7097 * delayed ref for that extent as well. This searches the delayed ref tree for
7098 * a given extent, and if there are no other delayed refs to be processed, it
7099 * removes it from the tree.
7100 */
7101 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
7102 struct btrfs_root *root, u64 bytenr)
7103 {
7104 struct btrfs_delayed_ref_head *head;
7105 struct btrfs_delayed_ref_root *delayed_refs;
7106 int ret = 0;
7107
7108 delayed_refs = &trans->transaction->delayed_refs;
7109 spin_lock(&delayed_refs->lock);
7110 head = btrfs_find_delayed_ref_head(trans, bytenr);
7111 if (!head)
7112 goto out_delayed_unlock;
7113
7114 spin_lock(&head->lock);
7115 if (!list_empty(&head->ref_list))
7116 goto out;
7117
7118 if (head->extent_op) {
7119 if (!head->must_insert_reserved)
7120 goto out;
7121 btrfs_free_delayed_extent_op(head->extent_op);
7122 head->extent_op = NULL;
7123 }
7124
7125 /*
7126 * waiting for the lock here would deadlock. If someone else has it
7127 * locked they are already in the process of dropping it anyway
7128 */
7129 if (!mutex_trylock(&head->mutex))
7130 goto out;
7131
7132 /*
7133 * at this point we have a head with no other entries. Go
7134 * ahead and process it.
7135 */
7136 head->node.in_tree = 0;
7137 rb_erase(&head->href_node, &delayed_refs->href_root);
7138
7139 atomic_dec(&delayed_refs->num_entries);
7140
7141 /*
7142 * we don't take a ref on the node because we're removing it from the
7143 * tree, so we just steal the ref the tree was holding.
7144 */
7145 delayed_refs->num_heads--;
7146 if (head->processing == 0)
7147 delayed_refs->num_heads_ready--;
7148 head->processing = 0;
7149 spin_unlock(&head->lock);
7150 spin_unlock(&delayed_refs->lock);
7151
7152 BUG_ON(head->extent_op);
7153 if (head->must_insert_reserved)
7154 ret = 1;
7155
7156 mutex_unlock(&head->mutex);
7157 btrfs_put_delayed_ref(&head->node);
7158 return ret;
7159 out:
7160 spin_unlock(&head->lock);
7161
7162 out_delayed_unlock:
7163 spin_unlock(&delayed_refs->lock);
7164 return 0;
7165 }
7166
7167 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
7168 struct btrfs_root *root,
7169 struct extent_buffer *buf,
7170 u64 parent, int last_ref)
7171 {
7172 int pin = 1;
7173 int ret;
7174
7175 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7176 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
7177 buf->start, buf->len,
7178 parent, root->root_key.objectid,
7179 btrfs_header_level(buf),
7180 BTRFS_DROP_DELAYED_REF, NULL);
7181 BUG_ON(ret); /* -ENOMEM */
7182 }
7183
7184 if (!last_ref)
7185 return;
7186
7187 if (btrfs_header_generation(buf) == trans->transid) {
7188 struct btrfs_block_group_cache *cache;
7189
7190 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7191 ret = check_ref_cleanup(trans, root, buf->start);
7192 if (!ret)
7193 goto out;
7194 }
7195
7196 cache = btrfs_lookup_block_group(root->fs_info, buf->start);
7197
7198 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
7199 pin_down_extent(root, cache, buf->start, buf->len, 1);
7200 btrfs_put_block_group(cache);
7201 goto out;
7202 }
7203
7204 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
7205
7206 btrfs_add_free_space(cache, buf->start, buf->len);
7207 btrfs_free_reserved_bytes(cache, buf->len, 0);
7208 btrfs_put_block_group(cache);
7209 trace_btrfs_reserved_extent_free(root, buf->start, buf->len);
7210 pin = 0;
7211 }
7212 out:
7213 if (pin)
7214 add_pinned_bytes(root->fs_info, buf->len,
7215 btrfs_header_level(buf),
7216 root->root_key.objectid);
7217
7218 /*
7219 * Deleting the buffer, clear the corrupt flag since it doesn't matter
7220 * anymore.
7221 */
7222 clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
7223 }
7224
7225 /* Can return -ENOMEM */
7226 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
7227 u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
7228 u64 owner, u64 offset)
7229 {
7230 int ret;
7231 struct btrfs_fs_info *fs_info = root->fs_info;
7232
7233 if (btrfs_is_testing(fs_info))
7234 return 0;
7235
7236 add_pinned_bytes(root->fs_info, num_bytes, owner, root_objectid);
7237
7238 /*
7239 * tree log blocks never actually go into the extent allocation
7240 * tree, just update pinning info and exit early.
7241 */
7242 if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
7243 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
7244 /* unlocks the pinned mutex */
7245 btrfs_pin_extent(root, bytenr, num_bytes, 1);
7246 ret = 0;
7247 } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
7248 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
7249 num_bytes,
7250 parent, root_objectid, (int)owner,
7251 BTRFS_DROP_DELAYED_REF, NULL);
7252 } else {
7253 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
7254 num_bytes,
7255 parent, root_objectid, owner,
7256 offset, 0,
7257 BTRFS_DROP_DELAYED_REF, NULL);
7258 }
7259 return ret;
7260 }
7261
7262 /*
7263 * when we wait for progress in the block group caching, its because
7264 * our allocation attempt failed at least once. So, we must sleep
7265 * and let some progress happen before we try again.
7266 *
7267 * This function will sleep at least once waiting for new free space to
7268 * show up, and then it will check the block group free space numbers
7269 * for our min num_bytes. Another option is to have it go ahead
7270 * and look in the rbtree for a free extent of a given size, but this
7271 * is a good start.
7272 *
7273 * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
7274 * any of the information in this block group.
7275 */
7276 static noinline void
7277 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
7278 u64 num_bytes)
7279 {
7280 struct btrfs_caching_control *caching_ctl;
7281
7282 caching_ctl = get_caching_control(cache);
7283 if (!caching_ctl)
7284 return;
7285
7286 wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
7287 (cache->free_space_ctl->free_space >= num_bytes));
7288
7289 put_caching_control(caching_ctl);
7290 }
7291
7292 static noinline int
7293 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
7294 {
7295 struct btrfs_caching_control *caching_ctl;
7296 int ret = 0;
7297
7298 caching_ctl = get_caching_control(cache);
7299 if (!caching_ctl)
7300 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
7301
7302 wait_event(caching_ctl->wait, block_group_cache_done(cache));
7303 if (cache->cached == BTRFS_CACHE_ERROR)
7304 ret = -EIO;
7305 put_caching_control(caching_ctl);
7306 return ret;
7307 }
7308
7309 int __get_raid_index(u64 flags)
7310 {
7311 if (flags & BTRFS_BLOCK_GROUP_RAID10)
7312 return BTRFS_RAID_RAID10;
7313 else if (flags & BTRFS_BLOCK_GROUP_RAID1)
7314 return BTRFS_RAID_RAID1;
7315 else if (flags & BTRFS_BLOCK_GROUP_DUP)
7316 return BTRFS_RAID_DUP;
7317 else if (flags & BTRFS_BLOCK_GROUP_RAID0)
7318 return BTRFS_RAID_RAID0;
7319 else if (flags & BTRFS_BLOCK_GROUP_RAID5)
7320 return BTRFS_RAID_RAID5;
7321 else if (flags & BTRFS_BLOCK_GROUP_RAID6)
7322 return BTRFS_RAID_RAID6;
7323
7324 return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
7325 }
7326
7327 int get_block_group_index(struct btrfs_block_group_cache *cache)
7328 {
7329 return __get_raid_index(cache->flags);
7330 }
7331
7332 static const char *btrfs_raid_type_names[BTRFS_NR_RAID_TYPES] = {
7333 [BTRFS_RAID_RAID10] = "raid10",
7334 [BTRFS_RAID_RAID1] = "raid1",
7335 [BTRFS_RAID_DUP] = "dup",
7336 [BTRFS_RAID_RAID0] = "raid0",
7337 [BTRFS_RAID_SINGLE] = "single",
7338 [BTRFS_RAID_RAID5] = "raid5",
7339 [BTRFS_RAID_RAID6] = "raid6",
7340 };
7341
7342 static const char *get_raid_name(enum btrfs_raid_types type)
7343 {
7344 if (type >= BTRFS_NR_RAID_TYPES)
7345 return NULL;
7346
7347 return btrfs_raid_type_names[type];
7348 }
7349
7350 enum btrfs_loop_type {
7351 LOOP_CACHING_NOWAIT = 0,
7352 LOOP_CACHING_WAIT = 1,
7353 LOOP_ALLOC_CHUNK = 2,
7354 LOOP_NO_EMPTY_SIZE = 3,
7355 };
7356
7357 static inline void
7358 btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
7359 int delalloc)
7360 {
7361 if (delalloc)
7362 down_read(&cache->data_rwsem);
7363 }
7364
7365 static inline void
7366 btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
7367 int delalloc)
7368 {
7369 btrfs_get_block_group(cache);
7370 if (delalloc)
7371 down_read(&cache->data_rwsem);
7372 }
7373
7374 static struct btrfs_block_group_cache *
7375 btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
7376 struct btrfs_free_cluster *cluster,
7377 int delalloc)
7378 {
7379 struct btrfs_block_group_cache *used_bg = NULL;
7380
7381 spin_lock(&cluster->refill_lock);
7382 while (1) {
7383 used_bg = cluster->block_group;
7384 if (!used_bg)
7385 return NULL;
7386
7387 if (used_bg == block_group)
7388 return used_bg;
7389
7390 btrfs_get_block_group(used_bg);
7391
7392 if (!delalloc)
7393 return used_bg;
7394
7395 if (down_read_trylock(&used_bg->data_rwsem))
7396 return used_bg;
7397
7398 spin_unlock(&cluster->refill_lock);
7399
7400 down_read(&used_bg->data_rwsem);
7401
7402 spin_lock(&cluster->refill_lock);
7403 if (used_bg == cluster->block_group)
7404 return used_bg;
7405
7406 up_read(&used_bg->data_rwsem);
7407 btrfs_put_block_group(used_bg);
7408 }
7409 }
7410
7411 static inline void
7412 btrfs_release_block_group(struct btrfs_block_group_cache *cache,
7413 int delalloc)
7414 {
7415 if (delalloc)
7416 up_read(&cache->data_rwsem);
7417 btrfs_put_block_group(cache);
7418 }
7419
7420 /*
7421 * walks the btree of allocated extents and find a hole of a given size.
7422 * The key ins is changed to record the hole:
7423 * ins->objectid == start position
7424 * ins->flags = BTRFS_EXTENT_ITEM_KEY
7425 * ins->offset == the size of the hole.
7426 * Any available blocks before search_start are skipped.
7427 *
7428 * If there is no suitable free space, we will record the max size of
7429 * the free space extent currently.
7430 */
7431 static noinline int find_free_extent(struct btrfs_root *orig_root,
7432 u64 ram_bytes, u64 num_bytes, u64 empty_size,
7433 u64 hint_byte, struct btrfs_key *ins,
7434 u64 flags, int delalloc)
7435 {
7436 int ret = 0;
7437 struct btrfs_root *root = orig_root->fs_info->extent_root;
7438 struct btrfs_free_cluster *last_ptr = NULL;
7439 struct btrfs_block_group_cache *block_group = NULL;
7440 u64 search_start = 0;
7441 u64 max_extent_size = 0;
7442 u64 empty_cluster = 0;
7443 struct btrfs_space_info *space_info;
7444 int loop = 0;
7445 int index = __get_raid_index(flags);
7446 bool failed_cluster_refill = false;
7447 bool failed_alloc = false;
7448 bool use_cluster = true;
7449 bool have_caching_bg = false;
7450 bool orig_have_caching_bg = false;
7451 bool full_search = false;
7452
7453 WARN_ON(num_bytes < root->sectorsize);
7454 ins->type = BTRFS_EXTENT_ITEM_KEY;
7455 ins->objectid = 0;
7456 ins->offset = 0;
7457
7458 trace_find_free_extent(orig_root, num_bytes, empty_size, flags);
7459
7460 space_info = __find_space_info(root->fs_info, flags);
7461 if (!space_info) {
7462 btrfs_err(root->fs_info, "No space info for %llu", flags);
7463 return -ENOSPC;
7464 }
7465
7466 /*
7467 * If our free space is heavily fragmented we may not be able to make
7468 * big contiguous allocations, so instead of doing the expensive search
7469 * for free space, simply return ENOSPC with our max_extent_size so we
7470 * can go ahead and search for a more manageable chunk.
7471 *
7472 * If our max_extent_size is large enough for our allocation simply
7473 * disable clustering since we will likely not be able to find enough
7474 * space to create a cluster and induce latency trying.
7475 */
7476 if (unlikely(space_info->max_extent_size)) {
7477 spin_lock(&space_info->lock);
7478 if (space_info->max_extent_size &&
7479 num_bytes > space_info->max_extent_size) {
7480 ins->offset = space_info->max_extent_size;
7481 spin_unlock(&space_info->lock);
7482 return -ENOSPC;
7483 } else if (space_info->max_extent_size) {
7484 use_cluster = false;
7485 }
7486 spin_unlock(&space_info->lock);
7487 }
7488
7489 last_ptr = fetch_cluster_info(orig_root, space_info, &empty_cluster);
7490 if (last_ptr) {
7491 spin_lock(&last_ptr->lock);
7492 if (last_ptr->block_group)
7493 hint_byte = last_ptr->window_start;
7494 if (last_ptr->fragmented) {
7495 /*
7496 * We still set window_start so we can keep track of the
7497 * last place we found an allocation to try and save
7498 * some time.
7499 */
7500 hint_byte = last_ptr->window_start;
7501 use_cluster = false;
7502 }
7503 spin_unlock(&last_ptr->lock);
7504 }
7505
7506 search_start = max(search_start, first_logical_byte(root, 0));
7507 search_start = max(search_start, hint_byte);
7508 if (search_start == hint_byte) {
7509 block_group = btrfs_lookup_block_group(root->fs_info,
7510 search_start);
7511 /*
7512 * we don't want to use the block group if it doesn't match our
7513 * allocation bits, or if its not cached.
7514 *
7515 * However if we are re-searching with an ideal block group
7516 * picked out then we don't care that the block group is cached.
7517 */
7518 if (block_group && block_group_bits(block_group, flags) &&
7519 block_group->cached != BTRFS_CACHE_NO) {
7520 down_read(&space_info->groups_sem);
7521 if (list_empty(&block_group->list) ||
7522 block_group->ro) {
7523 /*
7524 * someone is removing this block group,
7525 * we can't jump into the have_block_group
7526 * target because our list pointers are not
7527 * valid
7528 */
7529 btrfs_put_block_group(block_group);
7530 up_read(&space_info->groups_sem);
7531 } else {
7532 index = get_block_group_index(block_group);
7533 btrfs_lock_block_group(block_group, delalloc);
7534 goto have_block_group;
7535 }
7536 } else if (block_group) {
7537 btrfs_put_block_group(block_group);
7538 }
7539 }
7540 search:
7541 have_caching_bg = false;
7542 if (index == 0 || index == __get_raid_index(flags))
7543 full_search = true;
7544 down_read(&space_info->groups_sem);
7545 list_for_each_entry(block_group, &space_info->block_groups[index],
7546 list) {
7547 u64 offset;
7548 int cached;
7549
7550 btrfs_grab_block_group(block_group, delalloc);
7551 search_start = block_group->key.objectid;
7552
7553 /*
7554 * this can happen if we end up cycling through all the
7555 * raid types, but we want to make sure we only allocate
7556 * for the proper type.
7557 */
7558 if (!block_group_bits(block_group, flags)) {
7559 u64 extra = BTRFS_BLOCK_GROUP_DUP |
7560 BTRFS_BLOCK_GROUP_RAID1 |
7561 BTRFS_BLOCK_GROUP_RAID5 |
7562 BTRFS_BLOCK_GROUP_RAID6 |
7563 BTRFS_BLOCK_GROUP_RAID10;
7564
7565 /*
7566 * if they asked for extra copies and this block group
7567 * doesn't provide them, bail. This does allow us to
7568 * fill raid0 from raid1.
7569 */
7570 if ((flags & extra) && !(block_group->flags & extra))
7571 goto loop;
7572 }
7573
7574 have_block_group:
7575 cached = block_group_cache_done(block_group);
7576 if (unlikely(!cached)) {
7577 have_caching_bg = true;
7578 ret = cache_block_group(block_group, 0);
7579 BUG_ON(ret < 0);
7580 ret = 0;
7581 }
7582
7583 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
7584 goto loop;
7585 if (unlikely(block_group->ro))
7586 goto loop;
7587
7588 /*
7589 * Ok we want to try and use the cluster allocator, so
7590 * lets look there
7591 */
7592 if (last_ptr && use_cluster) {
7593 struct btrfs_block_group_cache *used_block_group;
7594 unsigned long aligned_cluster;
7595 /*
7596 * the refill lock keeps out other
7597 * people trying to start a new cluster
7598 */
7599 used_block_group = btrfs_lock_cluster(block_group,
7600 last_ptr,
7601 delalloc);
7602 if (!used_block_group)
7603 goto refill_cluster;
7604
7605 if (used_block_group != block_group &&
7606 (used_block_group->ro ||
7607 !block_group_bits(used_block_group, flags)))
7608 goto release_cluster;
7609
7610 offset = btrfs_alloc_from_cluster(used_block_group,
7611 last_ptr,
7612 num_bytes,
7613 used_block_group->key.objectid,
7614 &max_extent_size);
7615 if (offset) {
7616 /* we have a block, we're done */
7617 spin_unlock(&last_ptr->refill_lock);
7618 trace_btrfs_reserve_extent_cluster(root,
7619 used_block_group,
7620 search_start, num_bytes);
7621 if (used_block_group != block_group) {
7622 btrfs_release_block_group(block_group,
7623 delalloc);
7624 block_group = used_block_group;
7625 }
7626 goto checks;
7627 }
7628
7629 WARN_ON(last_ptr->block_group != used_block_group);
7630 release_cluster:
7631 /* If we are on LOOP_NO_EMPTY_SIZE, we can't
7632 * set up a new clusters, so lets just skip it
7633 * and let the allocator find whatever block
7634 * it can find. If we reach this point, we
7635 * will have tried the cluster allocator
7636 * plenty of times and not have found
7637 * anything, so we are likely way too
7638 * fragmented for the clustering stuff to find
7639 * anything.
7640 *
7641 * However, if the cluster is taken from the
7642 * current block group, release the cluster
7643 * first, so that we stand a better chance of
7644 * succeeding in the unclustered
7645 * allocation. */
7646 if (loop >= LOOP_NO_EMPTY_SIZE &&
7647 used_block_group != block_group) {
7648 spin_unlock(&last_ptr->refill_lock);
7649 btrfs_release_block_group(used_block_group,
7650 delalloc);
7651 goto unclustered_alloc;
7652 }
7653
7654 /*
7655 * this cluster didn't work out, free it and
7656 * start over
7657 */
7658 btrfs_return_cluster_to_free_space(NULL, last_ptr);
7659
7660 if (used_block_group != block_group)
7661 btrfs_release_block_group(used_block_group,
7662 delalloc);
7663 refill_cluster:
7664 if (loop >= LOOP_NO_EMPTY_SIZE) {
7665 spin_unlock(&last_ptr->refill_lock);
7666 goto unclustered_alloc;
7667 }
7668
7669 aligned_cluster = max_t(unsigned long,
7670 empty_cluster + empty_size,
7671 block_group->full_stripe_len);
7672
7673 /* allocate a cluster in this block group */
7674 ret = btrfs_find_space_cluster(root, block_group,
7675 last_ptr, search_start,
7676 num_bytes,
7677 aligned_cluster);
7678 if (ret == 0) {
7679 /*
7680 * now pull our allocation out of this
7681 * cluster
7682 */
7683 offset = btrfs_alloc_from_cluster(block_group,
7684 last_ptr,
7685 num_bytes,
7686 search_start,
7687 &max_extent_size);
7688 if (offset) {
7689 /* we found one, proceed */
7690 spin_unlock(&last_ptr->refill_lock);
7691 trace_btrfs_reserve_extent_cluster(root,
7692 block_group, search_start,
7693 num_bytes);
7694 goto checks;
7695 }
7696 } else if (!cached && loop > LOOP_CACHING_NOWAIT
7697 && !failed_cluster_refill) {
7698 spin_unlock(&last_ptr->refill_lock);
7699
7700 failed_cluster_refill = true;
7701 wait_block_group_cache_progress(block_group,
7702 num_bytes + empty_cluster + empty_size);
7703 goto have_block_group;
7704 }
7705
7706 /*
7707 * at this point we either didn't find a cluster
7708 * or we weren't able to allocate a block from our
7709 * cluster. Free the cluster we've been trying
7710 * to use, and go to the next block group
7711 */
7712 btrfs_return_cluster_to_free_space(NULL, last_ptr);
7713 spin_unlock(&last_ptr->refill_lock);
7714 goto loop;
7715 }
7716
7717 unclustered_alloc:
7718 /*
7719 * We are doing an unclustered alloc, set the fragmented flag so
7720 * we don't bother trying to setup a cluster again until we get
7721 * more space.
7722 */
7723 if (unlikely(last_ptr)) {
7724 spin_lock(&last_ptr->lock);
7725 last_ptr->fragmented = 1;
7726 spin_unlock(&last_ptr->lock);
7727 }
7728 spin_lock(&block_group->free_space_ctl->tree_lock);
7729 if (cached &&
7730 block_group->free_space_ctl->free_space <
7731 num_bytes + empty_cluster + empty_size) {
7732 if (block_group->free_space_ctl->free_space >
7733 max_extent_size)
7734 max_extent_size =
7735 block_group->free_space_ctl->free_space;
7736 spin_unlock(&block_group->free_space_ctl->tree_lock);
7737 goto loop;
7738 }
7739 spin_unlock(&block_group->free_space_ctl->tree_lock);
7740
7741 offset = btrfs_find_space_for_alloc(block_group, search_start,
7742 num_bytes, empty_size,
7743 &max_extent_size);
7744 /*
7745 * If we didn't find a chunk, and we haven't failed on this
7746 * block group before, and this block group is in the middle of
7747 * caching and we are ok with waiting, then go ahead and wait
7748 * for progress to be made, and set failed_alloc to true.
7749 *
7750 * If failed_alloc is true then we've already waited on this
7751 * block group once and should move on to the next block group.
7752 */
7753 if (!offset && !failed_alloc && !cached &&
7754 loop > LOOP_CACHING_NOWAIT) {
7755 wait_block_group_cache_progress(block_group,
7756 num_bytes + empty_size);
7757 failed_alloc = true;
7758 goto have_block_group;
7759 } else if (!offset) {
7760 goto loop;
7761 }
7762 checks:
7763 search_start = ALIGN(offset, root->stripesize);
7764
7765 /* move on to the next group */
7766 if (search_start + num_bytes >
7767 block_group->key.objectid + block_group->key.offset) {
7768 btrfs_add_free_space(block_group, offset, num_bytes);
7769 goto loop;
7770 }
7771
7772 if (offset < search_start)
7773 btrfs_add_free_space(block_group, offset,
7774 search_start - offset);
7775 BUG_ON(offset > search_start);
7776
7777 ret = btrfs_add_reserved_bytes(block_group, ram_bytes,
7778 num_bytes, delalloc);
7779 if (ret == -EAGAIN) {
7780 btrfs_add_free_space(block_group, offset, num_bytes);
7781 goto loop;
7782 }
7783 btrfs_inc_block_group_reservations(block_group);
7784
7785 /* we are all good, lets return */
7786 ins->objectid = search_start;
7787 ins->offset = num_bytes;
7788
7789 trace_btrfs_reserve_extent(orig_root, block_group,
7790 search_start, num_bytes);
7791 btrfs_release_block_group(block_group, delalloc);
7792 break;
7793 loop:
7794 failed_cluster_refill = false;
7795 failed_alloc = false;
7796 BUG_ON(index != get_block_group_index(block_group));
7797 btrfs_release_block_group(block_group, delalloc);
7798 }
7799 up_read(&space_info->groups_sem);
7800
7801 if ((loop == LOOP_CACHING_NOWAIT) && have_caching_bg
7802 && !orig_have_caching_bg)
7803 orig_have_caching_bg = true;
7804
7805 if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
7806 goto search;
7807
7808 if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
7809 goto search;
7810
7811 /*
7812 * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
7813 * caching kthreads as we move along
7814 * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
7815 * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
7816 * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
7817 * again
7818 */
7819 if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
7820 index = 0;
7821 if (loop == LOOP_CACHING_NOWAIT) {
7822 /*
7823 * We want to skip the LOOP_CACHING_WAIT step if we
7824 * don't have any uncached bgs and we've already done a
7825 * full search through.
7826 */
7827 if (orig_have_caching_bg || !full_search)
7828 loop = LOOP_CACHING_WAIT;
7829 else
7830 loop = LOOP_ALLOC_CHUNK;
7831 } else {
7832 loop++;
7833 }
7834
7835 if (loop == LOOP_ALLOC_CHUNK) {
7836 struct btrfs_trans_handle *trans;
7837 int exist = 0;
7838
7839 trans = current->journal_info;
7840 if (trans)
7841 exist = 1;
7842 else
7843 trans = btrfs_join_transaction(root);
7844
7845 if (IS_ERR(trans)) {
7846 ret = PTR_ERR(trans);
7847 goto out;
7848 }
7849
7850 ret = do_chunk_alloc(trans, root, flags,
7851 CHUNK_ALLOC_FORCE);
7852
7853 /*
7854 * If we can't allocate a new chunk we've already looped
7855 * through at least once, move on to the NO_EMPTY_SIZE
7856 * case.
7857 */
7858 if (ret == -ENOSPC)
7859 loop = LOOP_NO_EMPTY_SIZE;
7860
7861 /*
7862 * Do not bail out on ENOSPC since we
7863 * can do more things.
7864 */
7865 if (ret < 0 && ret != -ENOSPC)
7866 btrfs_abort_transaction(trans, ret);
7867 else
7868 ret = 0;
7869 if (!exist)
7870 btrfs_end_transaction(trans, root);
7871 if (ret)
7872 goto out;
7873 }
7874
7875 if (loop == LOOP_NO_EMPTY_SIZE) {
7876 /*
7877 * Don't loop again if we already have no empty_size and
7878 * no empty_cluster.
7879 */
7880 if (empty_size == 0 &&
7881 empty_cluster == 0) {
7882 ret = -ENOSPC;
7883 goto out;
7884 }
7885 empty_size = 0;
7886 empty_cluster = 0;
7887 }
7888
7889 goto search;
7890 } else if (!ins->objectid) {
7891 ret = -ENOSPC;
7892 } else if (ins->objectid) {
7893 if (!use_cluster && last_ptr) {
7894 spin_lock(&last_ptr->lock);
7895 last_ptr->window_start = ins->objectid;
7896 spin_unlock(&last_ptr->lock);
7897 }
7898 ret = 0;
7899 }
7900 out:
7901 if (ret == -ENOSPC) {
7902 spin_lock(&space_info->lock);
7903 space_info->max_extent_size = max_extent_size;
7904 spin_unlock(&space_info->lock);
7905 ins->offset = max_extent_size;
7906 }
7907 return ret;
7908 }
7909
7910 static void dump_space_info(struct btrfs_fs_info *fs_info,
7911 struct btrfs_space_info *info, u64 bytes,
7912 int dump_block_groups)
7913 {
7914 struct btrfs_block_group_cache *cache;
7915 int index = 0;
7916
7917 spin_lock(&info->lock);
7918 btrfs_info(fs_info, "space_info %llu has %llu free, is %sfull",
7919 info->flags,
7920 info->total_bytes - info->bytes_used - info->bytes_pinned -
7921 info->bytes_reserved - info->bytes_readonly -
7922 info->bytes_may_use, (info->full) ? "" : "not ");
7923 btrfs_info(fs_info,
7924 "space_info total=%llu, used=%llu, pinned=%llu, reserved=%llu, may_use=%llu, readonly=%llu",
7925 info->total_bytes, info->bytes_used, info->bytes_pinned,
7926 info->bytes_reserved, info->bytes_may_use,
7927 info->bytes_readonly);
7928 spin_unlock(&info->lock);
7929
7930 if (!dump_block_groups)
7931 return;
7932
7933 down_read(&info->groups_sem);
7934 again:
7935 list_for_each_entry(cache, &info->block_groups[index], list) {
7936 spin_lock(&cache->lock);
7937 btrfs_info(fs_info,
7938 "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %s",
7939 cache->key.objectid, cache->key.offset,
7940 btrfs_block_group_used(&cache->item), cache->pinned,
7941 cache->reserved, cache->ro ? "[readonly]" : "");
7942 btrfs_dump_free_space(cache, bytes);
7943 spin_unlock(&cache->lock);
7944 }
7945 if (++index < BTRFS_NR_RAID_TYPES)
7946 goto again;
7947 up_read(&info->groups_sem);
7948 }
7949
7950 int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes,
7951 u64 num_bytes, u64 min_alloc_size,
7952 u64 empty_size, u64 hint_byte,
7953 struct btrfs_key *ins, int is_data, int delalloc)
7954 {
7955 struct btrfs_fs_info *fs_info = root->fs_info;
7956 bool final_tried = num_bytes == min_alloc_size;
7957 u64 flags;
7958 int ret;
7959
7960 flags = btrfs_get_alloc_profile(root, is_data);
7961 again:
7962 WARN_ON(num_bytes < root->sectorsize);
7963 ret = find_free_extent(root, ram_bytes, num_bytes, empty_size,
7964 hint_byte, ins, flags, delalloc);
7965 if (!ret && !is_data) {
7966 btrfs_dec_block_group_reservations(fs_info, ins->objectid);
7967 } else if (ret == -ENOSPC) {
7968 if (!final_tried && ins->offset) {
7969 num_bytes = min(num_bytes >> 1, ins->offset);
7970 num_bytes = round_down(num_bytes, root->sectorsize);
7971 num_bytes = max(num_bytes, min_alloc_size);
7972 ram_bytes = num_bytes;
7973 if (num_bytes == min_alloc_size)
7974 final_tried = true;
7975 goto again;
7976 } else if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
7977 struct btrfs_space_info *sinfo;
7978
7979 sinfo = __find_space_info(fs_info, flags);
7980 btrfs_err(root->fs_info,
7981 "allocation failed flags %llu, wanted %llu",
7982 flags, num_bytes);
7983 if (sinfo)
7984 dump_space_info(fs_info, sinfo, num_bytes, 1);
7985 }
7986 }
7987
7988 return ret;
7989 }
7990
7991 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
7992 u64 start, u64 len,
7993 int pin, int delalloc)
7994 {
7995 struct btrfs_block_group_cache *cache;
7996 int ret = 0;
7997
7998 cache = btrfs_lookup_block_group(root->fs_info, start);
7999 if (!cache) {
8000 btrfs_err(root->fs_info, "Unable to find block group for %llu",
8001 start);
8002 return -ENOSPC;
8003 }
8004
8005 if (pin)
8006 pin_down_extent(root, cache, start, len, 1);
8007 else {
8008 if (btrfs_test_opt(root->fs_info, DISCARD))
8009 ret = btrfs_discard_extent(root, start, len, NULL);
8010 btrfs_add_free_space(cache, start, len);
8011 btrfs_free_reserved_bytes(cache, len, delalloc);
8012 trace_btrfs_reserved_extent_free(root, start, len);
8013 }
8014
8015 btrfs_put_block_group(cache);
8016 return ret;
8017 }
8018
8019 int btrfs_free_reserved_extent(struct btrfs_root *root,
8020 u64 start, u64 len, int delalloc)
8021 {
8022 return __btrfs_free_reserved_extent(root, start, len, 0, delalloc);
8023 }
8024
8025 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
8026 u64 start, u64 len)
8027 {
8028 return __btrfs_free_reserved_extent(root, start, len, 1, 0);
8029 }
8030
8031 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8032 struct btrfs_root *root,
8033 u64 parent, u64 root_objectid,
8034 u64 flags, u64 owner, u64 offset,
8035 struct btrfs_key *ins, int ref_mod)
8036 {
8037 int ret;
8038 struct btrfs_fs_info *fs_info = root->fs_info;
8039 struct btrfs_extent_item *extent_item;
8040 struct btrfs_extent_inline_ref *iref;
8041 struct btrfs_path *path;
8042 struct extent_buffer *leaf;
8043 int type;
8044 u32 size;
8045
8046 if (parent > 0)
8047 type = BTRFS_SHARED_DATA_REF_KEY;
8048 else
8049 type = BTRFS_EXTENT_DATA_REF_KEY;
8050
8051 size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
8052
8053 path = btrfs_alloc_path();
8054 if (!path)
8055 return -ENOMEM;
8056
8057 path->leave_spinning = 1;
8058 ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
8059 ins, size);
8060 if (ret) {
8061 btrfs_free_path(path);
8062 return ret;
8063 }
8064
8065 leaf = path->nodes[0];
8066 extent_item = btrfs_item_ptr(leaf, path->slots[0],
8067 struct btrfs_extent_item);
8068 btrfs_set_extent_refs(leaf, extent_item, ref_mod);
8069 btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8070 btrfs_set_extent_flags(leaf, extent_item,
8071 flags | BTRFS_EXTENT_FLAG_DATA);
8072
8073 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8074 btrfs_set_extent_inline_ref_type(leaf, iref, type);
8075 if (parent > 0) {
8076 struct btrfs_shared_data_ref *ref;
8077 ref = (struct btrfs_shared_data_ref *)(iref + 1);
8078 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
8079 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
8080 } else {
8081 struct btrfs_extent_data_ref *ref;
8082 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
8083 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
8084 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
8085 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
8086 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
8087 }
8088
8089 btrfs_mark_buffer_dirty(path->nodes[0]);
8090 btrfs_free_path(path);
8091
8092 ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
8093 ins->offset);
8094 if (ret)
8095 return ret;
8096
8097 ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
8098 if (ret) { /* -ENOENT, logic error */
8099 btrfs_err(fs_info, "update block group failed for %llu %llu",
8100 ins->objectid, ins->offset);
8101 BUG();
8102 }
8103 trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
8104 return ret;
8105 }
8106
8107 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
8108 struct btrfs_root *root,
8109 u64 parent, u64 root_objectid,
8110 u64 flags, struct btrfs_disk_key *key,
8111 int level, struct btrfs_key *ins)
8112 {
8113 int ret;
8114 struct btrfs_fs_info *fs_info = root->fs_info;
8115 struct btrfs_extent_item *extent_item;
8116 struct btrfs_tree_block_info *block_info;
8117 struct btrfs_extent_inline_ref *iref;
8118 struct btrfs_path *path;
8119 struct extent_buffer *leaf;
8120 u32 size = sizeof(*extent_item) + sizeof(*iref);
8121 u64 num_bytes = ins->offset;
8122 bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
8123 SKINNY_METADATA);
8124
8125 if (!skinny_metadata)
8126 size += sizeof(*block_info);
8127
8128 path = btrfs_alloc_path();
8129 if (!path) {
8130 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
8131 root->nodesize);
8132 return -ENOMEM;
8133 }
8134
8135 path->leave_spinning = 1;
8136 ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
8137 ins, size);
8138 if (ret) {
8139 btrfs_free_path(path);
8140 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
8141 root->nodesize);
8142 return ret;
8143 }
8144
8145 leaf = path->nodes[0];
8146 extent_item = btrfs_item_ptr(leaf, path->slots[0],
8147 struct btrfs_extent_item);
8148 btrfs_set_extent_refs(leaf, extent_item, 1);
8149 btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8150 btrfs_set_extent_flags(leaf, extent_item,
8151 flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
8152
8153 if (skinny_metadata) {
8154 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8155 num_bytes = root->nodesize;
8156 } else {
8157 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
8158 btrfs_set_tree_block_key(leaf, block_info, key);
8159 btrfs_set_tree_block_level(leaf, block_info, level);
8160 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
8161 }
8162
8163 if (parent > 0) {
8164 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
8165 btrfs_set_extent_inline_ref_type(leaf, iref,
8166 BTRFS_SHARED_BLOCK_REF_KEY);
8167 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
8168 } else {
8169 btrfs_set_extent_inline_ref_type(leaf, iref,
8170 BTRFS_TREE_BLOCK_REF_KEY);
8171 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
8172 }
8173
8174 btrfs_mark_buffer_dirty(leaf);
8175 btrfs_free_path(path);
8176
8177 ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
8178 num_bytes);
8179 if (ret)
8180 return ret;
8181
8182 ret = update_block_group(trans, root, ins->objectid, root->nodesize,
8183 1);
8184 if (ret) { /* -ENOENT, logic error */
8185 btrfs_err(fs_info, "update block group failed for %llu %llu",
8186 ins->objectid, ins->offset);
8187 BUG();
8188 }
8189
8190 trace_btrfs_reserved_extent_alloc(root, ins->objectid, root->nodesize);
8191 return ret;
8192 }
8193
8194 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8195 struct btrfs_root *root,
8196 u64 root_objectid, u64 owner,
8197 u64 offset, u64 ram_bytes,
8198 struct btrfs_key *ins)
8199 {
8200 int ret;
8201
8202 BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
8203
8204 ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
8205 ins->offset, 0,
8206 root_objectid, owner, offset,
8207 ram_bytes, BTRFS_ADD_DELAYED_EXTENT,
8208 NULL);
8209 return ret;
8210 }
8211
8212 /*
8213 * this is used by the tree logging recovery code. It records that
8214 * an extent has been allocated and makes sure to clear the free
8215 * space cache bits as well
8216 */
8217 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
8218 struct btrfs_root *root,
8219 u64 root_objectid, u64 owner, u64 offset,
8220 struct btrfs_key *ins)
8221 {
8222 int ret;
8223 struct btrfs_block_group_cache *block_group;
8224 struct btrfs_space_info *space_info;
8225
8226 /*
8227 * Mixed block groups will exclude before processing the log so we only
8228 * need to do the exclude dance if this fs isn't mixed.
8229 */
8230 if (!btrfs_fs_incompat(root->fs_info, MIXED_GROUPS)) {
8231 ret = __exclude_logged_extent(root, ins->objectid, ins->offset);
8232 if (ret)
8233 return ret;
8234 }
8235
8236 block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
8237 if (!block_group)
8238 return -EINVAL;
8239
8240 space_info = block_group->space_info;
8241 spin_lock(&space_info->lock);
8242 spin_lock(&block_group->lock);
8243 space_info->bytes_reserved += ins->offset;
8244 block_group->reserved += ins->offset;
8245 spin_unlock(&block_group->lock);
8246 spin_unlock(&space_info->lock);
8247
8248 ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
8249 0, owner, offset, ins, 1);
8250 btrfs_put_block_group(block_group);
8251 return ret;
8252 }
8253
8254 static struct extent_buffer *
8255 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
8256 u64 bytenr, int level)
8257 {
8258 struct extent_buffer *buf;
8259
8260 buf = btrfs_find_create_tree_block(root, bytenr);
8261 if (IS_ERR(buf))
8262 return buf;
8263
8264 btrfs_set_header_generation(buf, trans->transid);
8265 btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
8266 btrfs_tree_lock(buf);
8267 clean_tree_block(trans, root->fs_info, buf);
8268 clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
8269
8270 btrfs_set_lock_blocking(buf);
8271 set_extent_buffer_uptodate(buf);
8272
8273 if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
8274 buf->log_index = root->log_transid % 2;
8275 /*
8276 * we allow two log transactions at a time, use different
8277 * EXENT bit to differentiate dirty pages.
8278 */
8279 if (buf->log_index == 0)
8280 set_extent_dirty(&root->dirty_log_pages, buf->start,
8281 buf->start + buf->len - 1, GFP_NOFS);
8282 else
8283 set_extent_new(&root->dirty_log_pages, buf->start,
8284 buf->start + buf->len - 1);
8285 } else {
8286 buf->log_index = -1;
8287 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
8288 buf->start + buf->len - 1, GFP_NOFS);
8289 }
8290 trans->dirty = true;
8291 /* this returns a buffer locked for blocking */
8292 return buf;
8293 }
8294
8295 static struct btrfs_block_rsv *
8296 use_block_rsv(struct btrfs_trans_handle *trans,
8297 struct btrfs_root *root, u32 blocksize)
8298 {
8299 struct btrfs_block_rsv *block_rsv;
8300 struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
8301 int ret;
8302 bool global_updated = false;
8303
8304 block_rsv = get_block_rsv(trans, root);
8305
8306 if (unlikely(block_rsv->size == 0))
8307 goto try_reserve;
8308 again:
8309 ret = block_rsv_use_bytes(block_rsv, blocksize);
8310 if (!ret)
8311 return block_rsv;
8312
8313 if (block_rsv->failfast)
8314 return ERR_PTR(ret);
8315
8316 if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
8317 global_updated = true;
8318 update_global_block_rsv(root->fs_info);
8319 goto again;
8320 }
8321
8322 if (btrfs_test_opt(root->fs_info, ENOSPC_DEBUG)) {
8323 static DEFINE_RATELIMIT_STATE(_rs,
8324 DEFAULT_RATELIMIT_INTERVAL * 10,
8325 /*DEFAULT_RATELIMIT_BURST*/ 1);
8326 if (__ratelimit(&_rs))
8327 WARN(1, KERN_DEBUG
8328 "BTRFS: block rsv returned %d\n", ret);
8329 }
8330 try_reserve:
8331 ret = reserve_metadata_bytes(root, block_rsv, blocksize,
8332 BTRFS_RESERVE_NO_FLUSH);
8333 if (!ret)
8334 return block_rsv;
8335 /*
8336 * If we couldn't reserve metadata bytes try and use some from
8337 * the global reserve if its space type is the same as the global
8338 * reservation.
8339 */
8340 if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
8341 block_rsv->space_info == global_rsv->space_info) {
8342 ret = block_rsv_use_bytes(global_rsv, blocksize);
8343 if (!ret)
8344 return global_rsv;
8345 }
8346 return ERR_PTR(ret);
8347 }
8348
8349 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
8350 struct btrfs_block_rsv *block_rsv, u32 blocksize)
8351 {
8352 block_rsv_add_bytes(block_rsv, blocksize, 0);
8353 block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
8354 }
8355
8356 /*
8357 * finds a free extent and does all the dirty work required for allocation
8358 * returns the tree buffer or an ERR_PTR on error.
8359 */
8360 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
8361 struct btrfs_root *root,
8362 u64 parent, u64 root_objectid,
8363 struct btrfs_disk_key *key, int level,
8364 u64 hint, u64 empty_size)
8365 {
8366 struct btrfs_key ins;
8367 struct btrfs_block_rsv *block_rsv;
8368 struct extent_buffer *buf;
8369 struct btrfs_delayed_extent_op *extent_op;
8370 u64 flags = 0;
8371 int ret;
8372 u32 blocksize = root->nodesize;
8373 bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
8374 SKINNY_METADATA);
8375
8376 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
8377 if (btrfs_is_testing(root->fs_info)) {
8378 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
8379 level);
8380 if (!IS_ERR(buf))
8381 root->alloc_bytenr += blocksize;
8382 return buf;
8383 }
8384 #endif
8385
8386 block_rsv = use_block_rsv(trans, root, blocksize);
8387 if (IS_ERR(block_rsv))
8388 return ERR_CAST(block_rsv);
8389
8390 ret = btrfs_reserve_extent(root, blocksize, blocksize, blocksize,
8391 empty_size, hint, &ins, 0, 0);
8392 if (ret)
8393 goto out_unuse;
8394
8395 buf = btrfs_init_new_buffer(trans, root, ins.objectid, level);
8396 if (IS_ERR(buf)) {
8397 ret = PTR_ERR(buf);
8398 goto out_free_reserved;
8399 }
8400
8401 if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
8402 if (parent == 0)
8403 parent = ins.objectid;
8404 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
8405 } else
8406 BUG_ON(parent > 0);
8407
8408 if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
8409 extent_op = btrfs_alloc_delayed_extent_op();
8410 if (!extent_op) {
8411 ret = -ENOMEM;
8412 goto out_free_buf;
8413 }
8414 if (key)
8415 memcpy(&extent_op->key, key, sizeof(extent_op->key));
8416 else
8417 memset(&extent_op->key, 0, sizeof(extent_op->key));
8418 extent_op->flags_to_set = flags;
8419 extent_op->update_key = skinny_metadata ? false : true;
8420 extent_op->update_flags = true;
8421 extent_op->is_data = false;
8422 extent_op->level = level;
8423
8424 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
8425 ins.objectid, ins.offset,
8426 parent, root_objectid, level,
8427 BTRFS_ADD_DELAYED_EXTENT,
8428 extent_op);
8429 if (ret)
8430 goto out_free_delayed;
8431 }
8432 return buf;
8433
8434 out_free_delayed:
8435 btrfs_free_delayed_extent_op(extent_op);
8436 out_free_buf:
8437 free_extent_buffer(buf);
8438 out_free_reserved:
8439 btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 0);
8440 out_unuse:
8441 unuse_block_rsv(root->fs_info, block_rsv, blocksize);
8442 return ERR_PTR(ret);
8443 }
8444
8445 struct walk_control {
8446 u64 refs[BTRFS_MAX_LEVEL];
8447 u64 flags[BTRFS_MAX_LEVEL];
8448 struct btrfs_key update_progress;
8449 int stage;
8450 int level;
8451 int shared_level;
8452 int update_ref;
8453 int keep_locks;
8454 int reada_slot;
8455 int reada_count;
8456 int for_reloc;
8457 };
8458
8459 #define DROP_REFERENCE 1
8460 #define UPDATE_BACKREF 2
8461
8462 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
8463 struct btrfs_root *root,
8464 struct walk_control *wc,
8465 struct btrfs_path *path)
8466 {
8467 u64 bytenr;
8468 u64 generation;
8469 u64 refs;
8470 u64 flags;
8471 u32 nritems;
8472 struct btrfs_key key;
8473 struct extent_buffer *eb;
8474 int ret;
8475 int slot;
8476 int nread = 0;
8477
8478 if (path->slots[wc->level] < wc->reada_slot) {
8479 wc->reada_count = wc->reada_count * 2 / 3;
8480 wc->reada_count = max(wc->reada_count, 2);
8481 } else {
8482 wc->reada_count = wc->reada_count * 3 / 2;
8483 wc->reada_count = min_t(int, wc->reada_count,
8484 BTRFS_NODEPTRS_PER_BLOCK(root));
8485 }
8486
8487 eb = path->nodes[wc->level];
8488 nritems = btrfs_header_nritems(eb);
8489
8490 for (slot = path->slots[wc->level]; slot < nritems; slot++) {
8491 if (nread >= wc->reada_count)
8492 break;
8493
8494 cond_resched();
8495 bytenr = btrfs_node_blockptr(eb, slot);
8496 generation = btrfs_node_ptr_generation(eb, slot);
8497
8498 if (slot == path->slots[wc->level])
8499 goto reada;
8500
8501 if (wc->stage == UPDATE_BACKREF &&
8502 generation <= root->root_key.offset)
8503 continue;
8504
8505 /* We don't lock the tree block, it's OK to be racy here */
8506 ret = btrfs_lookup_extent_info(trans, root, bytenr,
8507 wc->level - 1, 1, &refs,
8508 &flags);
8509 /* We don't care about errors in readahead. */
8510 if (ret < 0)
8511 continue;
8512 BUG_ON(refs == 0);
8513
8514 if (wc->stage == DROP_REFERENCE) {
8515 if (refs == 1)
8516 goto reada;
8517
8518 if (wc->level == 1 &&
8519 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8520 continue;
8521 if (!wc->update_ref ||
8522 generation <= root->root_key.offset)
8523 continue;
8524 btrfs_node_key_to_cpu(eb, &key, slot);
8525 ret = btrfs_comp_cpu_keys(&key,
8526 &wc->update_progress);
8527 if (ret < 0)
8528 continue;
8529 } else {
8530 if (wc->level == 1 &&
8531 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8532 continue;
8533 }
8534 reada:
8535 readahead_tree_block(root, bytenr);
8536 nread++;
8537 }
8538 wc->reada_slot = slot;
8539 }
8540
8541 static int account_leaf_items(struct btrfs_trans_handle *trans,
8542 struct btrfs_root *root,
8543 struct extent_buffer *eb)
8544 {
8545 int nr = btrfs_header_nritems(eb);
8546 int i, extent_type, ret;
8547 struct btrfs_key key;
8548 struct btrfs_file_extent_item *fi;
8549 u64 bytenr, num_bytes;
8550
8551 /* We can be called directly from walk_up_proc() */
8552 if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &root->fs_info->flags))
8553 return 0;
8554
8555 for (i = 0; i < nr; i++) {
8556 btrfs_item_key_to_cpu(eb, &key, i);
8557
8558 if (key.type != BTRFS_EXTENT_DATA_KEY)
8559 continue;
8560
8561 fi = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
8562 /* filter out non qgroup-accountable extents */
8563 extent_type = btrfs_file_extent_type(eb, fi);
8564
8565 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
8566 continue;
8567
8568 bytenr = btrfs_file_extent_disk_bytenr(eb, fi);
8569 if (!bytenr)
8570 continue;
8571
8572 num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
8573
8574 ret = btrfs_qgroup_insert_dirty_extent(trans, root->fs_info,
8575 bytenr, num_bytes, GFP_NOFS);
8576 if (ret)
8577 return ret;
8578 }
8579 return 0;
8580 }
8581
8582 /*
8583 * Walk up the tree from the bottom, freeing leaves and any interior
8584 * nodes which have had all slots visited. If a node (leaf or
8585 * interior) is freed, the node above it will have it's slot
8586 * incremented. The root node will never be freed.
8587 *
8588 * At the end of this function, we should have a path which has all
8589 * slots incremented to the next position for a search. If we need to
8590 * read a new node it will be NULL and the node above it will have the
8591 * correct slot selected for a later read.
8592 *
8593 * If we increment the root nodes slot counter past the number of
8594 * elements, 1 is returned to signal completion of the search.
8595 */
8596 static int adjust_slots_upwards(struct btrfs_root *root,
8597 struct btrfs_path *path, int root_level)
8598 {
8599 int level = 0;
8600 int nr, slot;
8601 struct extent_buffer *eb;
8602
8603 if (root_level == 0)
8604 return 1;
8605
8606 while (level <= root_level) {
8607 eb = path->nodes[level];
8608 nr = btrfs_header_nritems(eb);
8609 path->slots[level]++;
8610 slot = path->slots[level];
8611 if (slot >= nr || level == 0) {
8612 /*
8613 * Don't free the root - we will detect this
8614 * condition after our loop and return a
8615 * positive value for caller to stop walking the tree.
8616 */
8617 if (level != root_level) {
8618 btrfs_tree_unlock_rw(eb, path->locks[level]);
8619 path->locks[level] = 0;
8620
8621 free_extent_buffer(eb);
8622 path->nodes[level] = NULL;
8623 path->slots[level] = 0;
8624 }
8625 } else {
8626 /*
8627 * We have a valid slot to walk back down
8628 * from. Stop here so caller can process these
8629 * new nodes.
8630 */
8631 break;
8632 }
8633
8634 level++;
8635 }
8636
8637 eb = path->nodes[root_level];
8638 if (path->slots[root_level] >= btrfs_header_nritems(eb))
8639 return 1;
8640
8641 return 0;
8642 }
8643
8644 /*
8645 * root_eb is the subtree root and is locked before this function is called.
8646 */
8647 static int account_shared_subtree(struct btrfs_trans_handle *trans,
8648 struct btrfs_root *root,
8649 struct extent_buffer *root_eb,
8650 u64 root_gen,
8651 int root_level)
8652 {
8653 int ret = 0;
8654 int level;
8655 struct extent_buffer *eb = root_eb;
8656 struct btrfs_path *path = NULL;
8657
8658 BUG_ON(root_level < 0 || root_level > BTRFS_MAX_LEVEL);
8659 BUG_ON(root_eb == NULL);
8660
8661 if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &root->fs_info->flags))
8662 return 0;
8663
8664 if (!extent_buffer_uptodate(root_eb)) {
8665 ret = btrfs_read_buffer(root_eb, root_gen);
8666 if (ret)
8667 goto out;
8668 }
8669
8670 if (root_level == 0) {
8671 ret = account_leaf_items(trans, root, root_eb);
8672 goto out;
8673 }
8674
8675 path = btrfs_alloc_path();
8676 if (!path)
8677 return -ENOMEM;
8678
8679 /*
8680 * Walk down the tree. Missing extent blocks are filled in as
8681 * we go. Metadata is accounted every time we read a new
8682 * extent block.
8683 *
8684 * When we reach a leaf, we account for file extent items in it,
8685 * walk back up the tree (adjusting slot pointers as we go)
8686 * and restart the search process.
8687 */
8688 extent_buffer_get(root_eb); /* For path */
8689 path->nodes[root_level] = root_eb;
8690 path->slots[root_level] = 0;
8691 path->locks[root_level] = 0; /* so release_path doesn't try to unlock */
8692 walk_down:
8693 level = root_level;
8694 while (level >= 0) {
8695 if (path->nodes[level] == NULL) {
8696 int parent_slot;
8697 u64 child_gen;
8698 u64 child_bytenr;
8699
8700 /* We need to get child blockptr/gen from
8701 * parent before we can read it. */
8702 eb = path->nodes[level + 1];
8703 parent_slot = path->slots[level + 1];
8704 child_bytenr = btrfs_node_blockptr(eb, parent_slot);
8705 child_gen = btrfs_node_ptr_generation(eb, parent_slot);
8706
8707 eb = read_tree_block(root, child_bytenr, child_gen);
8708 if (IS_ERR(eb)) {
8709 ret = PTR_ERR(eb);
8710 goto out;
8711 } else if (!extent_buffer_uptodate(eb)) {
8712 free_extent_buffer(eb);
8713 ret = -EIO;
8714 goto out;
8715 }
8716
8717 path->nodes[level] = eb;
8718 path->slots[level] = 0;
8719
8720 btrfs_tree_read_lock(eb);
8721 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
8722 path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
8723
8724 ret = btrfs_qgroup_insert_dirty_extent(trans,
8725 root->fs_info, child_bytenr,
8726 root->nodesize, GFP_NOFS);
8727 if (ret)
8728 goto out;
8729 }
8730
8731 if (level == 0) {
8732 ret = account_leaf_items(trans, root, path->nodes[level]);
8733 if (ret)
8734 goto out;
8735
8736 /* Nonzero return here means we completed our search */
8737 ret = adjust_slots_upwards(root, path, root_level);
8738 if (ret)
8739 break;
8740
8741 /* Restart search with new slots */
8742 goto walk_down;
8743 }
8744
8745 level--;
8746 }
8747
8748 ret = 0;
8749 out:
8750 btrfs_free_path(path);
8751
8752 return ret;
8753 }
8754
8755 /*
8756 * helper to process tree block while walking down the tree.
8757 *
8758 * when wc->stage == UPDATE_BACKREF, this function updates
8759 * back refs for pointers in the block.
8760 *
8761 * NOTE: return value 1 means we should stop walking down.
8762 */
8763 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
8764 struct btrfs_root *root,
8765 struct btrfs_path *path,
8766 struct walk_control *wc, int lookup_info)
8767 {
8768 int level = wc->level;
8769 struct extent_buffer *eb = path->nodes[level];
8770 u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8771 int ret;
8772
8773 if (wc->stage == UPDATE_BACKREF &&
8774 btrfs_header_owner(eb) != root->root_key.objectid)
8775 return 1;
8776
8777 /*
8778 * when reference count of tree block is 1, it won't increase
8779 * again. once full backref flag is set, we never clear it.
8780 */
8781 if (lookup_info &&
8782 ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
8783 (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
8784 BUG_ON(!path->locks[level]);
8785 ret = btrfs_lookup_extent_info(trans, root,
8786 eb->start, level, 1,
8787 &wc->refs[level],
8788 &wc->flags[level]);
8789 BUG_ON(ret == -ENOMEM);
8790 if (ret)
8791 return ret;
8792 BUG_ON(wc->refs[level] == 0);
8793 }
8794
8795 if (wc->stage == DROP_REFERENCE) {
8796 if (wc->refs[level] > 1)
8797 return 1;
8798
8799 if (path->locks[level] && !wc->keep_locks) {
8800 btrfs_tree_unlock_rw(eb, path->locks[level]);
8801 path->locks[level] = 0;
8802 }
8803 return 0;
8804 }
8805
8806 /* wc->stage == UPDATE_BACKREF */
8807 if (!(wc->flags[level] & flag)) {
8808 BUG_ON(!path->locks[level]);
8809 ret = btrfs_inc_ref(trans, root, eb, 1);
8810 BUG_ON(ret); /* -ENOMEM */
8811 ret = btrfs_dec_ref(trans, root, eb, 0);
8812 BUG_ON(ret); /* -ENOMEM */
8813 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
8814 eb->len, flag,
8815 btrfs_header_level(eb), 0);
8816 BUG_ON(ret); /* -ENOMEM */
8817 wc->flags[level] |= flag;
8818 }
8819
8820 /*
8821 * the block is shared by multiple trees, so it's not good to
8822 * keep the tree lock
8823 */
8824 if (path->locks[level] && level > 0) {
8825 btrfs_tree_unlock_rw(eb, path->locks[level]);
8826 path->locks[level] = 0;
8827 }
8828 return 0;
8829 }
8830
8831 /*
8832 * helper to process tree block pointer.
8833 *
8834 * when wc->stage == DROP_REFERENCE, this function checks
8835 * reference count of the block pointed to. if the block
8836 * is shared and we need update back refs for the subtree
8837 * rooted at the block, this function changes wc->stage to
8838 * UPDATE_BACKREF. if the block is shared and there is no
8839 * need to update back, this function drops the reference
8840 * to the block.
8841 *
8842 * NOTE: return value 1 means we should stop walking down.
8843 */
8844 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
8845 struct btrfs_root *root,
8846 struct btrfs_path *path,
8847 struct walk_control *wc, int *lookup_info)
8848 {
8849 u64 bytenr;
8850 u64 generation;
8851 u64 parent;
8852 u32 blocksize;
8853 struct btrfs_key key;
8854 struct extent_buffer *next;
8855 int level = wc->level;
8856 int reada = 0;
8857 int ret = 0;
8858 bool need_account = false;
8859
8860 generation = btrfs_node_ptr_generation(path->nodes[level],
8861 path->slots[level]);
8862 /*
8863 * if the lower level block was created before the snapshot
8864 * was created, we know there is no need to update back refs
8865 * for the subtree
8866 */
8867 if (wc->stage == UPDATE_BACKREF &&
8868 generation <= root->root_key.offset) {
8869 *lookup_info = 1;
8870 return 1;
8871 }
8872
8873 bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
8874 blocksize = root->nodesize;
8875
8876 next = btrfs_find_tree_block(root->fs_info, bytenr);
8877 if (!next) {
8878 next = btrfs_find_create_tree_block(root, bytenr);
8879 if (IS_ERR(next))
8880 return PTR_ERR(next);
8881
8882 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
8883 level - 1);
8884 reada = 1;
8885 }
8886 btrfs_tree_lock(next);
8887 btrfs_set_lock_blocking(next);
8888
8889 ret = btrfs_lookup_extent_info(trans, root, bytenr, level - 1, 1,
8890 &wc->refs[level - 1],
8891 &wc->flags[level - 1]);
8892 if (ret < 0)
8893 goto out_unlock;
8894
8895 if (unlikely(wc->refs[level - 1] == 0)) {
8896 btrfs_err(root->fs_info, "Missing references.");
8897 ret = -EIO;
8898 goto out_unlock;
8899 }
8900 *lookup_info = 0;
8901
8902 if (wc->stage == DROP_REFERENCE) {
8903 if (wc->refs[level - 1] > 1) {
8904 need_account = true;
8905 if (level == 1 &&
8906 (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8907 goto skip;
8908
8909 if (!wc->update_ref ||
8910 generation <= root->root_key.offset)
8911 goto skip;
8912
8913 btrfs_node_key_to_cpu(path->nodes[level], &key,
8914 path->slots[level]);
8915 ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
8916 if (ret < 0)
8917 goto skip;
8918
8919 wc->stage = UPDATE_BACKREF;
8920 wc->shared_level = level - 1;
8921 }
8922 } else {
8923 if (level == 1 &&
8924 (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8925 goto skip;
8926 }
8927
8928 if (!btrfs_buffer_uptodate(next, generation, 0)) {
8929 btrfs_tree_unlock(next);
8930 free_extent_buffer(next);
8931 next = NULL;
8932 *lookup_info = 1;
8933 }
8934
8935 if (!next) {
8936 if (reada && level == 1)
8937 reada_walk_down(trans, root, wc, path);
8938 next = read_tree_block(root, bytenr, generation);
8939 if (IS_ERR(next)) {
8940 return PTR_ERR(next);
8941 } else if (!extent_buffer_uptodate(next)) {
8942 free_extent_buffer(next);
8943 return -EIO;
8944 }
8945 btrfs_tree_lock(next);
8946 btrfs_set_lock_blocking(next);
8947 }
8948
8949 level--;
8950 ASSERT(level == btrfs_header_level(next));
8951 if (level != btrfs_header_level(next)) {
8952 btrfs_err(root->fs_info, "mismatched level");
8953 ret = -EIO;
8954 goto out_unlock;
8955 }
8956 path->nodes[level] = next;
8957 path->slots[level] = 0;
8958 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8959 wc->level = level;
8960 if (wc->level == 1)
8961 wc->reada_slot = 0;
8962 return 0;
8963 skip:
8964 wc->refs[level - 1] = 0;
8965 wc->flags[level - 1] = 0;
8966 if (wc->stage == DROP_REFERENCE) {
8967 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
8968 parent = path->nodes[level]->start;
8969 } else {
8970 ASSERT(root->root_key.objectid ==
8971 btrfs_header_owner(path->nodes[level]));
8972 if (root->root_key.objectid !=
8973 btrfs_header_owner(path->nodes[level])) {
8974 btrfs_err(root->fs_info,
8975 "mismatched block owner");
8976 ret = -EIO;
8977 goto out_unlock;
8978 }
8979 parent = 0;
8980 }
8981
8982 if (need_account) {
8983 ret = account_shared_subtree(trans, root, next,
8984 generation, level - 1);
8985 if (ret) {
8986 btrfs_err_rl(root->fs_info,
8987 "Error %d accounting shared subtree. Quota is out of sync, rescan required.",
8988 ret);
8989 }
8990 }
8991 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
8992 root->root_key.objectid, level - 1, 0);
8993 if (ret)
8994 goto out_unlock;
8995 }
8996
8997 *lookup_info = 1;
8998 ret = 1;
8999
9000 out_unlock:
9001 btrfs_tree_unlock(next);
9002 free_extent_buffer(next);
9003
9004 return ret;
9005 }
9006
9007 /*
9008 * helper to process tree block while walking up the tree.
9009 *
9010 * when wc->stage == DROP_REFERENCE, this function drops
9011 * reference count on the block.
9012 *
9013 * when wc->stage == UPDATE_BACKREF, this function changes
9014 * wc->stage back to DROP_REFERENCE if we changed wc->stage
9015 * to UPDATE_BACKREF previously while processing the block.
9016 *
9017 * NOTE: return value 1 means we should stop walking up.
9018 */
9019 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
9020 struct btrfs_root *root,
9021 struct btrfs_path *path,
9022 struct walk_control *wc)
9023 {
9024 int ret;
9025 int level = wc->level;
9026 struct extent_buffer *eb = path->nodes[level];
9027 u64 parent = 0;
9028
9029 if (wc->stage == UPDATE_BACKREF) {
9030 BUG_ON(wc->shared_level < level);
9031 if (level < wc->shared_level)
9032 goto out;
9033
9034 ret = find_next_key(path, level + 1, &wc->update_progress);
9035 if (ret > 0)
9036 wc->update_ref = 0;
9037
9038 wc->stage = DROP_REFERENCE;
9039 wc->shared_level = -1;
9040 path->slots[level] = 0;
9041
9042 /*
9043 * check reference count again if the block isn't locked.
9044 * we should start walking down the tree again if reference
9045 * count is one.
9046 */
9047 if (!path->locks[level]) {
9048 BUG_ON(level == 0);
9049 btrfs_tree_lock(eb);
9050 btrfs_set_lock_blocking(eb);
9051 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9052
9053 ret = btrfs_lookup_extent_info(trans, root,
9054 eb->start, level, 1,
9055 &wc->refs[level],
9056 &wc->flags[level]);
9057 if (ret < 0) {
9058 btrfs_tree_unlock_rw(eb, path->locks[level]);
9059 path->locks[level] = 0;
9060 return ret;
9061 }
9062 BUG_ON(wc->refs[level] == 0);
9063 if (wc->refs[level] == 1) {
9064 btrfs_tree_unlock_rw(eb, path->locks[level]);
9065 path->locks[level] = 0;
9066 return 1;
9067 }
9068 }
9069 }
9070
9071 /* wc->stage == DROP_REFERENCE */
9072 BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
9073
9074 if (wc->refs[level] == 1) {
9075 if (level == 0) {
9076 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
9077 ret = btrfs_dec_ref(trans, root, eb, 1);
9078 else
9079 ret = btrfs_dec_ref(trans, root, eb, 0);
9080 BUG_ON(ret); /* -ENOMEM */
9081 ret = account_leaf_items(trans, root, eb);
9082 if (ret) {
9083 btrfs_err_rl(root->fs_info,
9084 "error %d accounting leaf items. Quota is out of sync, rescan required.",
9085 ret);
9086 }
9087 }
9088 /* make block locked assertion in clean_tree_block happy */
9089 if (!path->locks[level] &&
9090 btrfs_header_generation(eb) == trans->transid) {
9091 btrfs_tree_lock(eb);
9092 btrfs_set_lock_blocking(eb);
9093 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9094 }
9095 clean_tree_block(trans, root->fs_info, eb);
9096 }
9097
9098 if (eb == root->node) {
9099 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
9100 parent = eb->start;
9101 else
9102 BUG_ON(root->root_key.objectid !=
9103 btrfs_header_owner(eb));
9104 } else {
9105 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
9106 parent = path->nodes[level + 1]->start;
9107 else
9108 BUG_ON(root->root_key.objectid !=
9109 btrfs_header_owner(path->nodes[level + 1]));
9110 }
9111
9112 btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
9113 out:
9114 wc->refs[level] = 0;
9115 wc->flags[level] = 0;
9116 return 0;
9117 }
9118
9119 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
9120 struct btrfs_root *root,
9121 struct btrfs_path *path,
9122 struct walk_control *wc)
9123 {
9124 int level = wc->level;
9125 int lookup_info = 1;
9126 int ret;
9127
9128 while (level >= 0) {
9129 ret = walk_down_proc(trans, root, path, wc, lookup_info);
9130 if (ret > 0)
9131 break;
9132
9133 if (level == 0)
9134 break;
9135
9136 if (path->slots[level] >=
9137 btrfs_header_nritems(path->nodes[level]))
9138 break;
9139
9140 ret = do_walk_down(trans, root, path, wc, &lookup_info);
9141 if (ret > 0) {
9142 path->slots[level]++;
9143 continue;
9144 } else if (ret < 0)
9145 return ret;
9146 level = wc->level;
9147 }
9148 return 0;
9149 }
9150
9151 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
9152 struct btrfs_root *root,
9153 struct btrfs_path *path,
9154 struct walk_control *wc, int max_level)
9155 {
9156 int level = wc->level;
9157 int ret;
9158
9159 path->slots[level] = btrfs_header_nritems(path->nodes[level]);
9160 while (level < max_level && path->nodes[level]) {
9161 wc->level = level;
9162 if (path->slots[level] + 1 <
9163 btrfs_header_nritems(path->nodes[level])) {
9164 path->slots[level]++;
9165 return 0;
9166 } else {
9167 ret = walk_up_proc(trans, root, path, wc);
9168 if (ret > 0)
9169 return 0;
9170
9171 if (path->locks[level]) {
9172 btrfs_tree_unlock_rw(path->nodes[level],
9173 path->locks[level]);
9174 path->locks[level] = 0;
9175 }
9176 free_extent_buffer(path->nodes[level]);
9177 path->nodes[level] = NULL;
9178 level++;
9179 }
9180 }
9181 return 1;
9182 }
9183
9184 /*
9185 * drop a subvolume tree.
9186 *
9187 * this function traverses the tree freeing any blocks that only
9188 * referenced by the tree.
9189 *
9190 * when a shared tree block is found. this function decreases its
9191 * reference count by one. if update_ref is true, this function
9192 * also make sure backrefs for the shared block and all lower level
9193 * blocks are properly updated.
9194 *
9195 * If called with for_reloc == 0, may exit early with -EAGAIN
9196 */
9197 int btrfs_drop_snapshot(struct btrfs_root *root,
9198 struct btrfs_block_rsv *block_rsv, int update_ref,
9199 int for_reloc)
9200 {
9201 struct btrfs_fs_info *fs_info = root->fs_info;
9202 struct btrfs_path *path;
9203 struct btrfs_trans_handle *trans;
9204 struct btrfs_root *tree_root = fs_info->tree_root;
9205 struct btrfs_root_item *root_item = &root->root_item;
9206 struct walk_control *wc;
9207 struct btrfs_key key;
9208 int err = 0;
9209 int ret;
9210 int level;
9211 bool root_dropped = false;
9212
9213 btrfs_debug(fs_info, "Drop subvolume %llu", root->objectid);
9214
9215 path = btrfs_alloc_path();
9216 if (!path) {
9217 err = -ENOMEM;
9218 goto out;
9219 }
9220
9221 wc = kzalloc(sizeof(*wc), GFP_NOFS);
9222 if (!wc) {
9223 btrfs_free_path(path);
9224 err = -ENOMEM;
9225 goto out;
9226 }
9227
9228 trans = btrfs_start_transaction(tree_root, 0);
9229 if (IS_ERR(trans)) {
9230 err = PTR_ERR(trans);
9231 goto out_free;
9232 }
9233
9234 if (block_rsv)
9235 trans->block_rsv = block_rsv;
9236
9237 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
9238 level = btrfs_header_level(root->node);
9239 path->nodes[level] = btrfs_lock_root_node(root);
9240 btrfs_set_lock_blocking(path->nodes[level]);
9241 path->slots[level] = 0;
9242 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9243 memset(&wc->update_progress, 0,
9244 sizeof(wc->update_progress));
9245 } else {
9246 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
9247 memcpy(&wc->update_progress, &key,
9248 sizeof(wc->update_progress));
9249
9250 level = root_item->drop_level;
9251 BUG_ON(level == 0);
9252 path->lowest_level = level;
9253 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
9254 path->lowest_level = 0;
9255 if (ret < 0) {
9256 err = ret;
9257 goto out_end_trans;
9258 }
9259 WARN_ON(ret > 0);
9260
9261 /*
9262 * unlock our path, this is safe because only this
9263 * function is allowed to delete this snapshot
9264 */
9265 btrfs_unlock_up_safe(path, 0);
9266
9267 level = btrfs_header_level(root->node);
9268 while (1) {
9269 btrfs_tree_lock(path->nodes[level]);
9270 btrfs_set_lock_blocking(path->nodes[level]);
9271 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9272
9273 ret = btrfs_lookup_extent_info(trans, root,
9274 path->nodes[level]->start,
9275 level, 1, &wc->refs[level],
9276 &wc->flags[level]);
9277 if (ret < 0) {
9278 err = ret;
9279 goto out_end_trans;
9280 }
9281 BUG_ON(wc->refs[level] == 0);
9282
9283 if (level == root_item->drop_level)
9284 break;
9285
9286 btrfs_tree_unlock(path->nodes[level]);
9287 path->locks[level] = 0;
9288 WARN_ON(wc->refs[level] != 1);
9289 level--;
9290 }
9291 }
9292
9293 wc->level = level;
9294 wc->shared_level = -1;
9295 wc->stage = DROP_REFERENCE;
9296 wc->update_ref = update_ref;
9297 wc->keep_locks = 0;
9298 wc->for_reloc = for_reloc;
9299 wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
9300
9301 while (1) {
9302
9303 ret = walk_down_tree(trans, root, path, wc);
9304 if (ret < 0) {
9305 err = ret;
9306 break;
9307 }
9308
9309 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
9310 if (ret < 0) {
9311 err = ret;
9312 break;
9313 }
9314
9315 if (ret > 0) {
9316 BUG_ON(wc->stage != DROP_REFERENCE);
9317 break;
9318 }
9319
9320 if (wc->stage == DROP_REFERENCE) {
9321 level = wc->level;
9322 btrfs_node_key(path->nodes[level],
9323 &root_item->drop_progress,
9324 path->slots[level]);
9325 root_item->drop_level = level;
9326 }
9327
9328 BUG_ON(wc->level == 0);
9329 if (btrfs_should_end_transaction(trans, tree_root) ||
9330 (!for_reloc && btrfs_need_cleaner_sleep(root))) {
9331 ret = btrfs_update_root(trans, tree_root,
9332 &root->root_key,
9333 root_item);
9334 if (ret) {
9335 btrfs_abort_transaction(trans, ret);
9336 err = ret;
9337 goto out_end_trans;
9338 }
9339
9340 btrfs_end_transaction_throttle(trans, tree_root);
9341 if (!for_reloc && btrfs_need_cleaner_sleep(root)) {
9342 btrfs_debug(fs_info,
9343 "drop snapshot early exit");
9344 err = -EAGAIN;
9345 goto out_free;
9346 }
9347
9348 trans = btrfs_start_transaction(tree_root, 0);
9349 if (IS_ERR(trans)) {
9350 err = PTR_ERR(trans);
9351 goto out_free;
9352 }
9353 if (block_rsv)
9354 trans->block_rsv = block_rsv;
9355 }
9356 }
9357 btrfs_release_path(path);
9358 if (err)
9359 goto out_end_trans;
9360
9361 ret = btrfs_del_root(trans, tree_root, &root->root_key);
9362 if (ret) {
9363 btrfs_abort_transaction(trans, ret);
9364 goto out_end_trans;
9365 }
9366
9367 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
9368 ret = btrfs_find_root(tree_root, &root->root_key, path,
9369 NULL, NULL);
9370 if (ret < 0) {
9371 btrfs_abort_transaction(trans, ret);
9372 err = ret;
9373 goto out_end_trans;
9374 } else if (ret > 0) {
9375 /* if we fail to delete the orphan item this time
9376 * around, it'll get picked up the next time.
9377 *
9378 * The most common failure here is just -ENOENT.
9379 */
9380 btrfs_del_orphan_item(trans, tree_root,
9381 root->root_key.objectid);
9382 }
9383 }
9384
9385 if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
9386 btrfs_add_dropped_root(trans, root);
9387 } else {
9388 free_extent_buffer(root->node);
9389 free_extent_buffer(root->commit_root);
9390 btrfs_put_fs_root(root);
9391 }
9392 root_dropped = true;
9393 out_end_trans:
9394 btrfs_end_transaction_throttle(trans, tree_root);
9395 out_free:
9396 kfree(wc);
9397 btrfs_free_path(path);
9398 out:
9399 /*
9400 * So if we need to stop dropping the snapshot for whatever reason we
9401 * need to make sure to add it back to the dead root list so that we
9402 * keep trying to do the work later. This also cleans up roots if we
9403 * don't have it in the radix (like when we recover after a power fail
9404 * or unmount) so we don't leak memory.
9405 */
9406 if (!for_reloc && root_dropped == false)
9407 btrfs_add_dead_root(root);
9408 if (err && err != -EAGAIN)
9409 btrfs_handle_fs_error(fs_info, err, NULL);
9410 return err;
9411 }
9412
9413 /*
9414 * drop subtree rooted at tree block 'node'.
9415 *
9416 * NOTE: this function will unlock and release tree block 'node'
9417 * only used by relocation code
9418 */
9419 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
9420 struct btrfs_root *root,
9421 struct extent_buffer *node,
9422 struct extent_buffer *parent)
9423 {
9424 struct btrfs_path *path;
9425 struct walk_control *wc;
9426 int level;
9427 int parent_level;
9428 int ret = 0;
9429 int wret;
9430
9431 BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
9432
9433 path = btrfs_alloc_path();
9434 if (!path)
9435 return -ENOMEM;
9436
9437 wc = kzalloc(sizeof(*wc), GFP_NOFS);
9438 if (!wc) {
9439 btrfs_free_path(path);
9440 return -ENOMEM;
9441 }
9442
9443 btrfs_assert_tree_locked(parent);
9444 parent_level = btrfs_header_level(parent);
9445 extent_buffer_get(parent);
9446 path->nodes[parent_level] = parent;
9447 path->slots[parent_level] = btrfs_header_nritems(parent);
9448
9449 btrfs_assert_tree_locked(node);
9450 level = btrfs_header_level(node);
9451 path->nodes[level] = node;
9452 path->slots[level] = 0;
9453 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9454
9455 wc->refs[parent_level] = 1;
9456 wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
9457 wc->level = level;
9458 wc->shared_level = -1;
9459 wc->stage = DROP_REFERENCE;
9460 wc->update_ref = 0;
9461 wc->keep_locks = 1;
9462 wc->for_reloc = 1;
9463 wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
9464
9465 while (1) {
9466 wret = walk_down_tree(trans, root, path, wc);
9467 if (wret < 0) {
9468 ret = wret;
9469 break;
9470 }
9471
9472 wret = walk_up_tree(trans, root, path, wc, parent_level);
9473 if (wret < 0)
9474 ret = wret;
9475 if (wret != 0)
9476 break;
9477 }
9478
9479 kfree(wc);
9480 btrfs_free_path(path);
9481 return ret;
9482 }
9483
9484 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
9485 {
9486 u64 num_devices;
9487 u64 stripped;
9488
9489 /*
9490 * if restripe for this chunk_type is on pick target profile and
9491 * return, otherwise do the usual balance
9492 */
9493 stripped = get_restripe_target(root->fs_info, flags);
9494 if (stripped)
9495 return extended_to_chunk(stripped);
9496
9497 num_devices = root->fs_info->fs_devices->rw_devices;
9498
9499 stripped = BTRFS_BLOCK_GROUP_RAID0 |
9500 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
9501 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
9502
9503 if (num_devices == 1) {
9504 stripped |= BTRFS_BLOCK_GROUP_DUP;
9505 stripped = flags & ~stripped;
9506
9507 /* turn raid0 into single device chunks */
9508 if (flags & BTRFS_BLOCK_GROUP_RAID0)
9509 return stripped;
9510
9511 /* turn mirroring into duplication */
9512 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
9513 BTRFS_BLOCK_GROUP_RAID10))
9514 return stripped | BTRFS_BLOCK_GROUP_DUP;
9515 } else {
9516 /* they already had raid on here, just return */
9517 if (flags & stripped)
9518 return flags;
9519
9520 stripped |= BTRFS_BLOCK_GROUP_DUP;
9521 stripped = flags & ~stripped;
9522
9523 /* switch duplicated blocks with raid1 */
9524 if (flags & BTRFS_BLOCK_GROUP_DUP)
9525 return stripped | BTRFS_BLOCK_GROUP_RAID1;
9526
9527 /* this is drive concat, leave it alone */
9528 }
9529
9530 return flags;
9531 }
9532
9533 static int inc_block_group_ro(struct btrfs_block_group_cache *cache, int force)
9534 {
9535 struct btrfs_space_info *sinfo = cache->space_info;
9536 u64 num_bytes;
9537 u64 min_allocable_bytes;
9538 int ret = -ENOSPC;
9539
9540 /*
9541 * We need some metadata space and system metadata space for
9542 * allocating chunks in some corner cases until we force to set
9543 * it to be readonly.
9544 */
9545 if ((sinfo->flags &
9546 (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
9547 !force)
9548 min_allocable_bytes = SZ_1M;
9549 else
9550 min_allocable_bytes = 0;
9551
9552 spin_lock(&sinfo->lock);
9553 spin_lock(&cache->lock);
9554
9555 if (cache->ro) {
9556 cache->ro++;
9557 ret = 0;
9558 goto out;
9559 }
9560
9561 num_bytes = cache->key.offset - cache->reserved - cache->pinned -
9562 cache->bytes_super - btrfs_block_group_used(&cache->item);
9563
9564 if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
9565 sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
9566 min_allocable_bytes <= sinfo->total_bytes) {
9567 sinfo->bytes_readonly += num_bytes;
9568 cache->ro++;
9569 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
9570 ret = 0;
9571 }
9572 out:
9573 spin_unlock(&cache->lock);
9574 spin_unlock(&sinfo->lock);
9575 return ret;
9576 }
9577
9578 int btrfs_inc_block_group_ro(struct btrfs_root *root,
9579 struct btrfs_block_group_cache *cache)
9580
9581 {
9582 struct btrfs_trans_handle *trans;
9583 u64 alloc_flags;
9584 int ret;
9585
9586 again:
9587 trans = btrfs_join_transaction(root);
9588 if (IS_ERR(trans))
9589 return PTR_ERR(trans);
9590
9591 /*
9592 * we're not allowed to set block groups readonly after the dirty
9593 * block groups cache has started writing. If it already started,
9594 * back off and let this transaction commit
9595 */
9596 mutex_lock(&root->fs_info->ro_block_group_mutex);
9597 if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
9598 u64 transid = trans->transid;
9599
9600 mutex_unlock(&root->fs_info->ro_block_group_mutex);
9601 btrfs_end_transaction(trans, root);
9602
9603 ret = btrfs_wait_for_commit(root, transid);
9604 if (ret)
9605 return ret;
9606 goto again;
9607 }
9608
9609 /*
9610 * if we are changing raid levels, try to allocate a corresponding
9611 * block group with the new raid level.
9612 */
9613 alloc_flags = update_block_group_flags(root, cache->flags);
9614 if (alloc_flags != cache->flags) {
9615 ret = do_chunk_alloc(trans, root, alloc_flags,
9616 CHUNK_ALLOC_FORCE);
9617 /*
9618 * ENOSPC is allowed here, we may have enough space
9619 * already allocated at the new raid level to
9620 * carry on
9621 */
9622 if (ret == -ENOSPC)
9623 ret = 0;
9624 if (ret < 0)
9625 goto out;
9626 }
9627
9628 ret = inc_block_group_ro(cache, 0);
9629 if (!ret)
9630 goto out;
9631 alloc_flags = get_alloc_profile(root, cache->space_info->flags);
9632 ret = do_chunk_alloc(trans, root, alloc_flags,
9633 CHUNK_ALLOC_FORCE);
9634 if (ret < 0)
9635 goto out;
9636 ret = inc_block_group_ro(cache, 0);
9637 out:
9638 if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
9639 alloc_flags = update_block_group_flags(root, cache->flags);
9640 lock_chunks(root->fs_info->chunk_root);
9641 check_system_chunk(trans, root, alloc_flags);
9642 unlock_chunks(root->fs_info->chunk_root);
9643 }
9644 mutex_unlock(&root->fs_info->ro_block_group_mutex);
9645
9646 btrfs_end_transaction(trans, root);
9647 return ret;
9648 }
9649
9650 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
9651 struct btrfs_root *root, u64 type)
9652 {
9653 u64 alloc_flags = get_alloc_profile(root, type);
9654 return do_chunk_alloc(trans, root, alloc_flags,
9655 CHUNK_ALLOC_FORCE);
9656 }
9657
9658 /*
9659 * helper to account the unused space of all the readonly block group in the
9660 * space_info. takes mirrors into account.
9661 */
9662 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
9663 {
9664 struct btrfs_block_group_cache *block_group;
9665 u64 free_bytes = 0;
9666 int factor;
9667
9668 /* It's df, we don't care if it's racy */
9669 if (list_empty(&sinfo->ro_bgs))
9670 return 0;
9671
9672 spin_lock(&sinfo->lock);
9673 list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
9674 spin_lock(&block_group->lock);
9675
9676 if (!block_group->ro) {
9677 spin_unlock(&block_group->lock);
9678 continue;
9679 }
9680
9681 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
9682 BTRFS_BLOCK_GROUP_RAID10 |
9683 BTRFS_BLOCK_GROUP_DUP))
9684 factor = 2;
9685 else
9686 factor = 1;
9687
9688 free_bytes += (block_group->key.offset -
9689 btrfs_block_group_used(&block_group->item)) *
9690 factor;
9691
9692 spin_unlock(&block_group->lock);
9693 }
9694 spin_unlock(&sinfo->lock);
9695
9696 return free_bytes;
9697 }
9698
9699 void btrfs_dec_block_group_ro(struct btrfs_root *root,
9700 struct btrfs_block_group_cache *cache)
9701 {
9702 struct btrfs_space_info *sinfo = cache->space_info;
9703 u64 num_bytes;
9704
9705 BUG_ON(!cache->ro);
9706
9707 spin_lock(&sinfo->lock);
9708 spin_lock(&cache->lock);
9709 if (!--cache->ro) {
9710 num_bytes = cache->key.offset - cache->reserved -
9711 cache->pinned - cache->bytes_super -
9712 btrfs_block_group_used(&cache->item);
9713 sinfo->bytes_readonly -= num_bytes;
9714 list_del_init(&cache->ro_list);
9715 }
9716 spin_unlock(&cache->lock);
9717 spin_unlock(&sinfo->lock);
9718 }
9719
9720 /*
9721 * checks to see if its even possible to relocate this block group.
9722 *
9723 * @return - -1 if it's not a good idea to relocate this block group, 0 if its
9724 * ok to go ahead and try.
9725 */
9726 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
9727 {
9728 struct btrfs_block_group_cache *block_group;
9729 struct btrfs_space_info *space_info;
9730 struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
9731 struct btrfs_device *device;
9732 struct btrfs_trans_handle *trans;
9733 u64 min_free;
9734 u64 dev_min = 1;
9735 u64 dev_nr = 0;
9736 u64 target;
9737 int debug;
9738 int index;
9739 int full = 0;
9740 int ret = 0;
9741
9742 debug = btrfs_test_opt(root->fs_info, ENOSPC_DEBUG);
9743
9744 block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
9745
9746 /* odd, couldn't find the block group, leave it alone */
9747 if (!block_group) {
9748 if (debug)
9749 btrfs_warn(root->fs_info,
9750 "can't find block group for bytenr %llu",
9751 bytenr);
9752 return -1;
9753 }
9754
9755 min_free = btrfs_block_group_used(&block_group->item);
9756
9757 /* no bytes used, we're good */
9758 if (!min_free)
9759 goto out;
9760
9761 space_info = block_group->space_info;
9762 spin_lock(&space_info->lock);
9763
9764 full = space_info->full;
9765
9766 /*
9767 * if this is the last block group we have in this space, we can't
9768 * relocate it unless we're able to allocate a new chunk below.
9769 *
9770 * Otherwise, we need to make sure we have room in the space to handle
9771 * all of the extents from this block group. If we can, we're good
9772 */
9773 if ((space_info->total_bytes != block_group->key.offset) &&
9774 (space_info->bytes_used + space_info->bytes_reserved +
9775 space_info->bytes_pinned + space_info->bytes_readonly +
9776 min_free < space_info->total_bytes)) {
9777 spin_unlock(&space_info->lock);
9778 goto out;
9779 }
9780 spin_unlock(&space_info->lock);
9781
9782 /*
9783 * ok we don't have enough space, but maybe we have free space on our
9784 * devices to allocate new chunks for relocation, so loop through our
9785 * alloc devices and guess if we have enough space. if this block
9786 * group is going to be restriped, run checks against the target
9787 * profile instead of the current one.
9788 */
9789 ret = -1;
9790
9791 /*
9792 * index:
9793 * 0: raid10
9794 * 1: raid1
9795 * 2: dup
9796 * 3: raid0
9797 * 4: single
9798 */
9799 target = get_restripe_target(root->fs_info, block_group->flags);
9800 if (target) {
9801 index = __get_raid_index(extended_to_chunk(target));
9802 } else {
9803 /*
9804 * this is just a balance, so if we were marked as full
9805 * we know there is no space for a new chunk
9806 */
9807 if (full) {
9808 if (debug)
9809 btrfs_warn(root->fs_info,
9810 "no space to alloc new chunk for block group %llu",
9811 block_group->key.objectid);
9812 goto out;
9813 }
9814
9815 index = get_block_group_index(block_group);
9816 }
9817
9818 if (index == BTRFS_RAID_RAID10) {
9819 dev_min = 4;
9820 /* Divide by 2 */
9821 min_free >>= 1;
9822 } else if (index == BTRFS_RAID_RAID1) {
9823 dev_min = 2;
9824 } else if (index == BTRFS_RAID_DUP) {
9825 /* Multiply by 2 */
9826 min_free <<= 1;
9827 } else if (index == BTRFS_RAID_RAID0) {
9828 dev_min = fs_devices->rw_devices;
9829 min_free = div64_u64(min_free, dev_min);
9830 }
9831
9832 /* We need to do this so that we can look at pending chunks */
9833 trans = btrfs_join_transaction(root);
9834 if (IS_ERR(trans)) {
9835 ret = PTR_ERR(trans);
9836 goto out;
9837 }
9838
9839 mutex_lock(&root->fs_info->chunk_mutex);
9840 list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
9841 u64 dev_offset;
9842
9843 /*
9844 * check to make sure we can actually find a chunk with enough
9845 * space to fit our block group in.
9846 */
9847 if (device->total_bytes > device->bytes_used + min_free &&
9848 !device->is_tgtdev_for_dev_replace) {
9849 ret = find_free_dev_extent(trans, device, min_free,
9850 &dev_offset, NULL);
9851 if (!ret)
9852 dev_nr++;
9853
9854 if (dev_nr >= dev_min)
9855 break;
9856
9857 ret = -1;
9858 }
9859 }
9860 if (debug && ret == -1)
9861 btrfs_warn(root->fs_info,
9862 "no space to allocate a new chunk for block group %llu",
9863 block_group->key.objectid);
9864 mutex_unlock(&root->fs_info->chunk_mutex);
9865 btrfs_end_transaction(trans, root);
9866 out:
9867 btrfs_put_block_group(block_group);
9868 return ret;
9869 }
9870
9871 static int find_first_block_group(struct btrfs_root *root,
9872 struct btrfs_path *path, struct btrfs_key *key)
9873 {
9874 int ret = 0;
9875 struct btrfs_key found_key;
9876 struct extent_buffer *leaf;
9877 int slot;
9878
9879 ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
9880 if (ret < 0)
9881 goto out;
9882
9883 while (1) {
9884 slot = path->slots[0];
9885 leaf = path->nodes[0];
9886 if (slot >= btrfs_header_nritems(leaf)) {
9887 ret = btrfs_next_leaf(root, path);
9888 if (ret == 0)
9889 continue;
9890 if (ret < 0)
9891 goto out;
9892 break;
9893 }
9894 btrfs_item_key_to_cpu(leaf, &found_key, slot);
9895
9896 if (found_key.objectid >= key->objectid &&
9897 found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
9898 struct extent_map_tree *em_tree;
9899 struct extent_map *em;
9900
9901 em_tree = &root->fs_info->mapping_tree.map_tree;
9902 read_lock(&em_tree->lock);
9903 em = lookup_extent_mapping(em_tree, found_key.objectid,
9904 found_key.offset);
9905 read_unlock(&em_tree->lock);
9906 if (!em) {
9907 btrfs_err(root->fs_info,
9908 "logical %llu len %llu found bg but no related chunk",
9909 found_key.objectid, found_key.offset);
9910 ret = -ENOENT;
9911 } else {
9912 ret = 0;
9913 }
9914 free_extent_map(em);
9915 goto out;
9916 }
9917 path->slots[0]++;
9918 }
9919 out:
9920 return ret;
9921 }
9922
9923 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
9924 {
9925 struct btrfs_block_group_cache *block_group;
9926 u64 last = 0;
9927
9928 while (1) {
9929 struct inode *inode;
9930
9931 block_group = btrfs_lookup_first_block_group(info, last);
9932 while (block_group) {
9933 spin_lock(&block_group->lock);
9934 if (block_group->iref)
9935 break;
9936 spin_unlock(&block_group->lock);
9937 block_group = next_block_group(info->tree_root,
9938 block_group);
9939 }
9940 if (!block_group) {
9941 if (last == 0)
9942 break;
9943 last = 0;
9944 continue;
9945 }
9946
9947 inode = block_group->inode;
9948 block_group->iref = 0;
9949 block_group->inode = NULL;
9950 spin_unlock(&block_group->lock);
9951 ASSERT(block_group->io_ctl.inode == NULL);
9952 iput(inode);
9953 last = block_group->key.objectid + block_group->key.offset;
9954 btrfs_put_block_group(block_group);
9955 }
9956 }
9957
9958 int btrfs_free_block_groups(struct btrfs_fs_info *info)
9959 {
9960 struct btrfs_block_group_cache *block_group;
9961 struct btrfs_space_info *space_info;
9962 struct btrfs_caching_control *caching_ctl;
9963 struct rb_node *n;
9964
9965 down_write(&info->commit_root_sem);
9966 while (!list_empty(&info->caching_block_groups)) {
9967 caching_ctl = list_entry(info->caching_block_groups.next,
9968 struct btrfs_caching_control, list);
9969 list_del(&caching_ctl->list);
9970 put_caching_control(caching_ctl);
9971 }
9972 up_write(&info->commit_root_sem);
9973
9974 spin_lock(&info->unused_bgs_lock);
9975 while (!list_empty(&info->unused_bgs)) {
9976 block_group = list_first_entry(&info->unused_bgs,
9977 struct btrfs_block_group_cache,
9978 bg_list);
9979 list_del_init(&block_group->bg_list);
9980 btrfs_put_block_group(block_group);
9981 }
9982 spin_unlock(&info->unused_bgs_lock);
9983
9984 spin_lock(&info->block_group_cache_lock);
9985 while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
9986 block_group = rb_entry(n, struct btrfs_block_group_cache,
9987 cache_node);
9988 rb_erase(&block_group->cache_node,
9989 &info->block_group_cache_tree);
9990 RB_CLEAR_NODE(&block_group->cache_node);
9991 spin_unlock(&info->block_group_cache_lock);
9992
9993 down_write(&block_group->space_info->groups_sem);
9994 list_del(&block_group->list);
9995 up_write(&block_group->space_info->groups_sem);
9996
9997 if (block_group->cached == BTRFS_CACHE_STARTED)
9998 wait_block_group_cache_done(block_group);
9999
10000 /*
10001 * We haven't cached this block group, which means we could
10002 * possibly have excluded extents on this block group.
10003 */
10004 if (block_group->cached == BTRFS_CACHE_NO ||
10005 block_group->cached == BTRFS_CACHE_ERROR)
10006 free_excluded_extents(info->extent_root, block_group);
10007
10008 btrfs_remove_free_space_cache(block_group);
10009 ASSERT(list_empty(&block_group->dirty_list));
10010 ASSERT(list_empty(&block_group->io_list));
10011 ASSERT(list_empty(&block_group->bg_list));
10012 ASSERT(atomic_read(&block_group->count) == 1);
10013 btrfs_put_block_group(block_group);
10014
10015 spin_lock(&info->block_group_cache_lock);
10016 }
10017 spin_unlock(&info->block_group_cache_lock);
10018
10019 /* now that all the block groups are freed, go through and
10020 * free all the space_info structs. This is only called during
10021 * the final stages of unmount, and so we know nobody is
10022 * using them. We call synchronize_rcu() once before we start,
10023 * just to be on the safe side.
10024 */
10025 synchronize_rcu();
10026
10027 release_global_block_rsv(info);
10028
10029 while (!list_empty(&info->space_info)) {
10030 int i;
10031
10032 space_info = list_entry(info->space_info.next,
10033 struct btrfs_space_info,
10034 list);
10035
10036 /*
10037 * Do not hide this behind enospc_debug, this is actually
10038 * important and indicates a real bug if this happens.
10039 */
10040 if (WARN_ON(space_info->bytes_pinned > 0 ||
10041 space_info->bytes_reserved > 0 ||
10042 space_info->bytes_may_use > 0))
10043 dump_space_info(info, space_info, 0, 0);
10044 list_del(&space_info->list);
10045 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
10046 struct kobject *kobj;
10047 kobj = space_info->block_group_kobjs[i];
10048 space_info->block_group_kobjs[i] = NULL;
10049 if (kobj) {
10050 kobject_del(kobj);
10051 kobject_put(kobj);
10052 }
10053 }
10054 kobject_del(&space_info->kobj);
10055 kobject_put(&space_info->kobj);
10056 }
10057 return 0;
10058 }
10059
10060 static void __link_block_group(struct btrfs_space_info *space_info,
10061 struct btrfs_block_group_cache *cache)
10062 {
10063 int index = get_block_group_index(cache);
10064 bool first = false;
10065
10066 down_write(&space_info->groups_sem);
10067 if (list_empty(&space_info->block_groups[index]))
10068 first = true;
10069 list_add_tail(&cache->list, &space_info->block_groups[index]);
10070 up_write(&space_info->groups_sem);
10071
10072 if (first) {
10073 struct raid_kobject *rkobj;
10074 int ret;
10075
10076 rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
10077 if (!rkobj)
10078 goto out_err;
10079 rkobj->raid_type = index;
10080 kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
10081 ret = kobject_add(&rkobj->kobj, &space_info->kobj,
10082 "%s", get_raid_name(index));
10083 if (ret) {
10084 kobject_put(&rkobj->kobj);
10085 goto out_err;
10086 }
10087 space_info->block_group_kobjs[index] = &rkobj->kobj;
10088 }
10089
10090 return;
10091 out_err:
10092 btrfs_warn(cache->fs_info,
10093 "failed to add kobject for block cache, ignoring");
10094 }
10095
10096 static struct btrfs_block_group_cache *
10097 btrfs_create_block_group_cache(struct btrfs_root *root, u64 start, u64 size)
10098 {
10099 struct btrfs_block_group_cache *cache;
10100
10101 cache = kzalloc(sizeof(*cache), GFP_NOFS);
10102 if (!cache)
10103 return NULL;
10104
10105 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
10106 GFP_NOFS);
10107 if (!cache->free_space_ctl) {
10108 kfree(cache);
10109 return NULL;
10110 }
10111
10112 cache->key.objectid = start;
10113 cache->key.offset = size;
10114 cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
10115
10116 cache->sectorsize = root->sectorsize;
10117 cache->fs_info = root->fs_info;
10118 cache->full_stripe_len = btrfs_full_stripe_len(root,
10119 &root->fs_info->mapping_tree,
10120 start);
10121 set_free_space_tree_thresholds(cache);
10122
10123 atomic_set(&cache->count, 1);
10124 spin_lock_init(&cache->lock);
10125 init_rwsem(&cache->data_rwsem);
10126 INIT_LIST_HEAD(&cache->list);
10127 INIT_LIST_HEAD(&cache->cluster_list);
10128 INIT_LIST_HEAD(&cache->bg_list);
10129 INIT_LIST_HEAD(&cache->ro_list);
10130 INIT_LIST_HEAD(&cache->dirty_list);
10131 INIT_LIST_HEAD(&cache->io_list);
10132 btrfs_init_free_space_ctl(cache);
10133 atomic_set(&cache->trimming, 0);
10134 mutex_init(&cache->free_space_lock);
10135
10136 return cache;
10137 }
10138
10139 int btrfs_read_block_groups(struct btrfs_root *root)
10140 {
10141 struct btrfs_path *path;
10142 int ret;
10143 struct btrfs_block_group_cache *cache;
10144 struct btrfs_fs_info *info = root->fs_info;
10145 struct btrfs_space_info *space_info;
10146 struct btrfs_key key;
10147 struct btrfs_key found_key;
10148 struct extent_buffer *leaf;
10149 int need_clear = 0;
10150 u64 cache_gen;
10151 u64 feature;
10152 int mixed;
10153
10154 feature = btrfs_super_incompat_flags(info->super_copy);
10155 mixed = !!(feature & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS);
10156
10157 root = info->extent_root;
10158 key.objectid = 0;
10159 key.offset = 0;
10160 key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
10161 path = btrfs_alloc_path();
10162 if (!path)
10163 return -ENOMEM;
10164 path->reada = READA_FORWARD;
10165
10166 cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
10167 if (btrfs_test_opt(root->fs_info, SPACE_CACHE) &&
10168 btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
10169 need_clear = 1;
10170 if (btrfs_test_opt(root->fs_info, CLEAR_CACHE))
10171 need_clear = 1;
10172
10173 while (1) {
10174 ret = find_first_block_group(root, path, &key);
10175 if (ret > 0)
10176 break;
10177 if (ret != 0)
10178 goto error;
10179
10180 leaf = path->nodes[0];
10181 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
10182
10183 cache = btrfs_create_block_group_cache(root, found_key.objectid,
10184 found_key.offset);
10185 if (!cache) {
10186 ret = -ENOMEM;
10187 goto error;
10188 }
10189
10190 if (need_clear) {
10191 /*
10192 * When we mount with old space cache, we need to
10193 * set BTRFS_DC_CLEAR and set dirty flag.
10194 *
10195 * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
10196 * truncate the old free space cache inode and
10197 * setup a new one.
10198 * b) Setting 'dirty flag' makes sure that we flush
10199 * the new space cache info onto disk.
10200 */
10201 if (btrfs_test_opt(root->fs_info, SPACE_CACHE))
10202 cache->disk_cache_state = BTRFS_DC_CLEAR;
10203 }
10204
10205 read_extent_buffer(leaf, &cache->item,
10206 btrfs_item_ptr_offset(leaf, path->slots[0]),
10207 sizeof(cache->item));
10208 cache->flags = btrfs_block_group_flags(&cache->item);
10209 if (!mixed &&
10210 ((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
10211 (cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
10212 btrfs_err(info,
10213 "bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
10214 cache->key.objectid);
10215 ret = -EINVAL;
10216 goto error;
10217 }
10218
10219 key.objectid = found_key.objectid + found_key.offset;
10220 btrfs_release_path(path);
10221
10222 /*
10223 * We need to exclude the super stripes now so that the space
10224 * info has super bytes accounted for, otherwise we'll think
10225 * we have more space than we actually do.
10226 */
10227 ret = exclude_super_stripes(root, cache);
10228 if (ret) {
10229 /*
10230 * We may have excluded something, so call this just in
10231 * case.
10232 */
10233 free_excluded_extents(root, cache);
10234 btrfs_put_block_group(cache);
10235 goto error;
10236 }
10237
10238 /*
10239 * check for two cases, either we are full, and therefore
10240 * don't need to bother with the caching work since we won't
10241 * find any space, or we are empty, and we can just add all
10242 * the space in and be done with it. This saves us _alot_ of
10243 * time, particularly in the full case.
10244 */
10245 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
10246 cache->last_byte_to_unpin = (u64)-1;
10247 cache->cached = BTRFS_CACHE_FINISHED;
10248 free_excluded_extents(root, cache);
10249 } else if (btrfs_block_group_used(&cache->item) == 0) {
10250 cache->last_byte_to_unpin = (u64)-1;
10251 cache->cached = BTRFS_CACHE_FINISHED;
10252 add_new_free_space(cache, root->fs_info,
10253 found_key.objectid,
10254 found_key.objectid +
10255 found_key.offset);
10256 free_excluded_extents(root, cache);
10257 }
10258
10259 ret = btrfs_add_block_group_cache(root->fs_info, cache);
10260 if (ret) {
10261 btrfs_remove_free_space_cache(cache);
10262 btrfs_put_block_group(cache);
10263 goto error;
10264 }
10265
10266 trace_btrfs_add_block_group(root->fs_info, cache, 0);
10267 ret = update_space_info(info, cache->flags, found_key.offset,
10268 btrfs_block_group_used(&cache->item),
10269 cache->bytes_super, &space_info);
10270 if (ret) {
10271 btrfs_remove_free_space_cache(cache);
10272 spin_lock(&info->block_group_cache_lock);
10273 rb_erase(&cache->cache_node,
10274 &info->block_group_cache_tree);
10275 RB_CLEAR_NODE(&cache->cache_node);
10276 spin_unlock(&info->block_group_cache_lock);
10277 btrfs_put_block_group(cache);
10278 goto error;
10279 }
10280
10281 cache->space_info = space_info;
10282
10283 __link_block_group(space_info, cache);
10284
10285 set_avail_alloc_bits(root->fs_info, cache->flags);
10286 if (btrfs_chunk_readonly(root, cache->key.objectid)) {
10287 inc_block_group_ro(cache, 1);
10288 } else if (btrfs_block_group_used(&cache->item) == 0) {
10289 spin_lock(&info->unused_bgs_lock);
10290 /* Should always be true but just in case. */
10291 if (list_empty(&cache->bg_list)) {
10292 btrfs_get_block_group(cache);
10293 list_add_tail(&cache->bg_list,
10294 &info->unused_bgs);
10295 }
10296 spin_unlock(&info->unused_bgs_lock);
10297 }
10298 }
10299
10300 list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
10301 if (!(get_alloc_profile(root, space_info->flags) &
10302 (BTRFS_BLOCK_GROUP_RAID10 |
10303 BTRFS_BLOCK_GROUP_RAID1 |
10304 BTRFS_BLOCK_GROUP_RAID5 |
10305 BTRFS_BLOCK_GROUP_RAID6 |
10306 BTRFS_BLOCK_GROUP_DUP)))
10307 continue;
10308 /*
10309 * avoid allocating from un-mirrored block group if there are
10310 * mirrored block groups.
10311 */
10312 list_for_each_entry(cache,
10313 &space_info->block_groups[BTRFS_RAID_RAID0],
10314 list)
10315 inc_block_group_ro(cache, 1);
10316 list_for_each_entry(cache,
10317 &space_info->block_groups[BTRFS_RAID_SINGLE],
10318 list)
10319 inc_block_group_ro(cache, 1);
10320 }
10321
10322 init_global_block_rsv(info);
10323 ret = 0;
10324 error:
10325 btrfs_free_path(path);
10326 return ret;
10327 }
10328
10329 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
10330 struct btrfs_root *root)
10331 {
10332 struct btrfs_block_group_cache *block_group, *tmp;
10333 struct btrfs_root *extent_root = root->fs_info->extent_root;
10334 struct btrfs_block_group_item item;
10335 struct btrfs_key key;
10336 int ret = 0;
10337 bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
10338
10339 trans->can_flush_pending_bgs = false;
10340 list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
10341 if (ret)
10342 goto next;
10343
10344 spin_lock(&block_group->lock);
10345 memcpy(&item, &block_group->item, sizeof(item));
10346 memcpy(&key, &block_group->key, sizeof(key));
10347 spin_unlock(&block_group->lock);
10348
10349 ret = btrfs_insert_item(trans, extent_root, &key, &item,
10350 sizeof(item));
10351 if (ret)
10352 btrfs_abort_transaction(trans, ret);
10353 ret = btrfs_finish_chunk_alloc(trans, extent_root,
10354 key.objectid, key.offset);
10355 if (ret)
10356 btrfs_abort_transaction(trans, ret);
10357 add_block_group_free_space(trans, root->fs_info, block_group);
10358 /* already aborted the transaction if it failed. */
10359 next:
10360 list_del_init(&block_group->bg_list);
10361 }
10362 trans->can_flush_pending_bgs = can_flush_pending_bgs;
10363 }
10364
10365 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
10366 struct btrfs_root *root, u64 bytes_used,
10367 u64 type, u64 chunk_objectid, u64 chunk_offset,
10368 u64 size)
10369 {
10370 int ret;
10371 struct btrfs_root *extent_root;
10372 struct btrfs_block_group_cache *cache;
10373 extent_root = root->fs_info->extent_root;
10374
10375 btrfs_set_log_full_commit(root->fs_info, trans);
10376
10377 cache = btrfs_create_block_group_cache(root, chunk_offset, size);
10378 if (!cache)
10379 return -ENOMEM;
10380
10381 btrfs_set_block_group_used(&cache->item, bytes_used);
10382 btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
10383 btrfs_set_block_group_flags(&cache->item, type);
10384
10385 cache->flags = type;
10386 cache->last_byte_to_unpin = (u64)-1;
10387 cache->cached = BTRFS_CACHE_FINISHED;
10388 cache->needs_free_space = 1;
10389 ret = exclude_super_stripes(root, cache);
10390 if (ret) {
10391 /*
10392 * We may have excluded something, so call this just in
10393 * case.
10394 */
10395 free_excluded_extents(root, cache);
10396 btrfs_put_block_group(cache);
10397 return ret;
10398 }
10399
10400 add_new_free_space(cache, root->fs_info, chunk_offset,
10401 chunk_offset + size);
10402
10403 free_excluded_extents(root, cache);
10404
10405 #ifdef CONFIG_BTRFS_DEBUG
10406 if (btrfs_should_fragment_free_space(root, cache)) {
10407 u64 new_bytes_used = size - bytes_used;
10408
10409 bytes_used += new_bytes_used >> 1;
10410 fragment_free_space(root, cache);
10411 }
10412 #endif
10413 /*
10414 * Call to ensure the corresponding space_info object is created and
10415 * assigned to our block group, but don't update its counters just yet.
10416 * We want our bg to be added to the rbtree with its ->space_info set.
10417 */
10418 ret = update_space_info(root->fs_info, cache->flags, 0, 0, 0,
10419 &cache->space_info);
10420 if (ret) {
10421 btrfs_remove_free_space_cache(cache);
10422 btrfs_put_block_group(cache);
10423 return ret;
10424 }
10425
10426 ret = btrfs_add_block_group_cache(root->fs_info, cache);
10427 if (ret) {
10428 btrfs_remove_free_space_cache(cache);
10429 btrfs_put_block_group(cache);
10430 return ret;
10431 }
10432
10433 /*
10434 * Now that our block group has its ->space_info set and is inserted in
10435 * the rbtree, update the space info's counters.
10436 */
10437 trace_btrfs_add_block_group(root->fs_info, cache, 1);
10438 ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
10439 cache->bytes_super, &cache->space_info);
10440 if (ret) {
10441 btrfs_remove_free_space_cache(cache);
10442 spin_lock(&root->fs_info->block_group_cache_lock);
10443 rb_erase(&cache->cache_node,
10444 &root->fs_info->block_group_cache_tree);
10445 RB_CLEAR_NODE(&cache->cache_node);
10446 spin_unlock(&root->fs_info->block_group_cache_lock);
10447 btrfs_put_block_group(cache);
10448 return ret;
10449 }
10450 update_global_block_rsv(root->fs_info);
10451
10452 __link_block_group(cache->space_info, cache);
10453
10454 list_add_tail(&cache->bg_list, &trans->new_bgs);
10455
10456 set_avail_alloc_bits(extent_root->fs_info, type);
10457 return 0;
10458 }
10459
10460 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
10461 {
10462 u64 extra_flags = chunk_to_extended(flags) &
10463 BTRFS_EXTENDED_PROFILE_MASK;
10464
10465 write_seqlock(&fs_info->profiles_lock);
10466 if (flags & BTRFS_BLOCK_GROUP_DATA)
10467 fs_info->avail_data_alloc_bits &= ~extra_flags;
10468 if (flags & BTRFS_BLOCK_GROUP_METADATA)
10469 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
10470 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
10471 fs_info->avail_system_alloc_bits &= ~extra_flags;
10472 write_sequnlock(&fs_info->profiles_lock);
10473 }
10474
10475 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
10476 struct btrfs_root *root, u64 group_start,
10477 struct extent_map *em)
10478 {
10479 struct btrfs_path *path;
10480 struct btrfs_block_group_cache *block_group;
10481 struct btrfs_free_cluster *cluster;
10482 struct btrfs_root *tree_root = root->fs_info->tree_root;
10483 struct btrfs_key key;
10484 struct inode *inode;
10485 struct kobject *kobj = NULL;
10486 int ret;
10487 int index;
10488 int factor;
10489 struct btrfs_caching_control *caching_ctl = NULL;
10490 bool remove_em;
10491
10492 root = root->fs_info->extent_root;
10493
10494 block_group = btrfs_lookup_block_group(root->fs_info, group_start);
10495 BUG_ON(!block_group);
10496 BUG_ON(!block_group->ro);
10497
10498 /*
10499 * Free the reserved super bytes from this block group before
10500 * remove it.
10501 */
10502 free_excluded_extents(root, block_group);
10503
10504 memcpy(&key, &block_group->key, sizeof(key));
10505 index = get_block_group_index(block_group);
10506 if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
10507 BTRFS_BLOCK_GROUP_RAID1 |
10508 BTRFS_BLOCK_GROUP_RAID10))
10509 factor = 2;
10510 else
10511 factor = 1;
10512
10513 /* make sure this block group isn't part of an allocation cluster */
10514 cluster = &root->fs_info->data_alloc_cluster;
10515 spin_lock(&cluster->refill_lock);
10516 btrfs_return_cluster_to_free_space(block_group, cluster);
10517 spin_unlock(&cluster->refill_lock);
10518
10519 /*
10520 * make sure this block group isn't part of a metadata
10521 * allocation cluster
10522 */
10523 cluster = &root->fs_info->meta_alloc_cluster;
10524 spin_lock(&cluster->refill_lock);
10525 btrfs_return_cluster_to_free_space(block_group, cluster);
10526 spin_unlock(&cluster->refill_lock);
10527
10528 path = btrfs_alloc_path();
10529 if (!path) {
10530 ret = -ENOMEM;
10531 goto out;
10532 }
10533
10534 /*
10535 * get the inode first so any iput calls done for the io_list
10536 * aren't the final iput (no unlinks allowed now)
10537 */
10538 inode = lookup_free_space_inode(tree_root, block_group, path);
10539
10540 mutex_lock(&trans->transaction->cache_write_mutex);
10541 /*
10542 * make sure our free spache cache IO is done before remove the
10543 * free space inode
10544 */
10545 spin_lock(&trans->transaction->dirty_bgs_lock);
10546 if (!list_empty(&block_group->io_list)) {
10547 list_del_init(&block_group->io_list);
10548
10549 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
10550
10551 spin_unlock(&trans->transaction->dirty_bgs_lock);
10552 btrfs_wait_cache_io(root, trans, block_group,
10553 &block_group->io_ctl, path,
10554 block_group->key.objectid);
10555 btrfs_put_block_group(block_group);
10556 spin_lock(&trans->transaction->dirty_bgs_lock);
10557 }
10558
10559 if (!list_empty(&block_group->dirty_list)) {
10560 list_del_init(&block_group->dirty_list);
10561 btrfs_put_block_group(block_group);
10562 }
10563 spin_unlock(&trans->transaction->dirty_bgs_lock);
10564 mutex_unlock(&trans->transaction->cache_write_mutex);
10565
10566 if (!IS_ERR(inode)) {
10567 ret = btrfs_orphan_add(trans, inode);
10568 if (ret) {
10569 btrfs_add_delayed_iput(inode);
10570 goto out;
10571 }
10572 clear_nlink(inode);
10573 /* One for the block groups ref */
10574 spin_lock(&block_group->lock);
10575 if (block_group->iref) {
10576 block_group->iref = 0;
10577 block_group->inode = NULL;
10578 spin_unlock(&block_group->lock);
10579 iput(inode);
10580 } else {
10581 spin_unlock(&block_group->lock);
10582 }
10583 /* One for our lookup ref */
10584 btrfs_add_delayed_iput(inode);
10585 }
10586
10587 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
10588 key.offset = block_group->key.objectid;
10589 key.type = 0;
10590
10591 ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
10592 if (ret < 0)
10593 goto out;
10594 if (ret > 0)
10595 btrfs_release_path(path);
10596 if (ret == 0) {
10597 ret = btrfs_del_item(trans, tree_root, path);
10598 if (ret)
10599 goto out;
10600 btrfs_release_path(path);
10601 }
10602
10603 spin_lock(&root->fs_info->block_group_cache_lock);
10604 rb_erase(&block_group->cache_node,
10605 &root->fs_info->block_group_cache_tree);
10606 RB_CLEAR_NODE(&block_group->cache_node);
10607
10608 if (root->fs_info->first_logical_byte == block_group->key.objectid)
10609 root->fs_info->first_logical_byte = (u64)-1;
10610 spin_unlock(&root->fs_info->block_group_cache_lock);
10611
10612 down_write(&block_group->space_info->groups_sem);
10613 /*
10614 * we must use list_del_init so people can check to see if they
10615 * are still on the list after taking the semaphore
10616 */
10617 list_del_init(&block_group->list);
10618 if (list_empty(&block_group->space_info->block_groups[index])) {
10619 kobj = block_group->space_info->block_group_kobjs[index];
10620 block_group->space_info->block_group_kobjs[index] = NULL;
10621 clear_avail_alloc_bits(root->fs_info, block_group->flags);
10622 }
10623 up_write(&block_group->space_info->groups_sem);
10624 if (kobj) {
10625 kobject_del(kobj);
10626 kobject_put(kobj);
10627 }
10628
10629 if (block_group->has_caching_ctl)
10630 caching_ctl = get_caching_control(block_group);
10631 if (block_group->cached == BTRFS_CACHE_STARTED)
10632 wait_block_group_cache_done(block_group);
10633 if (block_group->has_caching_ctl) {
10634 down_write(&root->fs_info->commit_root_sem);
10635 if (!caching_ctl) {
10636 struct btrfs_caching_control *ctl;
10637
10638 list_for_each_entry(ctl,
10639 &root->fs_info->caching_block_groups, list)
10640 if (ctl->block_group == block_group) {
10641 caching_ctl = ctl;
10642 atomic_inc(&caching_ctl->count);
10643 break;
10644 }
10645 }
10646 if (caching_ctl)
10647 list_del_init(&caching_ctl->list);
10648 up_write(&root->fs_info->commit_root_sem);
10649 if (caching_ctl) {
10650 /* Once for the caching bgs list and once for us. */
10651 put_caching_control(caching_ctl);
10652 put_caching_control(caching_ctl);
10653 }
10654 }
10655
10656 spin_lock(&trans->transaction->dirty_bgs_lock);
10657 if (!list_empty(&block_group->dirty_list)) {
10658 WARN_ON(1);
10659 }
10660 if (!list_empty(&block_group->io_list)) {
10661 WARN_ON(1);
10662 }
10663 spin_unlock(&trans->transaction->dirty_bgs_lock);
10664 btrfs_remove_free_space_cache(block_group);
10665
10666 spin_lock(&block_group->space_info->lock);
10667 list_del_init(&block_group->ro_list);
10668
10669 if (btrfs_test_opt(root->fs_info, ENOSPC_DEBUG)) {
10670 WARN_ON(block_group->space_info->total_bytes
10671 < block_group->key.offset);
10672 WARN_ON(block_group->space_info->bytes_readonly
10673 < block_group->key.offset);
10674 WARN_ON(block_group->space_info->disk_total
10675 < block_group->key.offset * factor);
10676 }
10677 block_group->space_info->total_bytes -= block_group->key.offset;
10678 block_group->space_info->bytes_readonly -= block_group->key.offset;
10679 block_group->space_info->disk_total -= block_group->key.offset * factor;
10680
10681 spin_unlock(&block_group->space_info->lock);
10682
10683 memcpy(&key, &block_group->key, sizeof(key));
10684
10685 lock_chunks(root);
10686 if (!list_empty(&em->list)) {
10687 /* We're in the transaction->pending_chunks list. */
10688 free_extent_map(em);
10689 }
10690 spin_lock(&block_group->lock);
10691 block_group->removed = 1;
10692 /*
10693 * At this point trimming can't start on this block group, because we
10694 * removed the block group from the tree fs_info->block_group_cache_tree
10695 * so no one can't find it anymore and even if someone already got this
10696 * block group before we removed it from the rbtree, they have already
10697 * incremented block_group->trimming - if they didn't, they won't find
10698 * any free space entries because we already removed them all when we
10699 * called btrfs_remove_free_space_cache().
10700 *
10701 * And we must not remove the extent map from the fs_info->mapping_tree
10702 * to prevent the same logical address range and physical device space
10703 * ranges from being reused for a new block group. This is because our
10704 * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
10705 * completely transactionless, so while it is trimming a range the
10706 * currently running transaction might finish and a new one start,
10707 * allowing for new block groups to be created that can reuse the same
10708 * physical device locations unless we take this special care.
10709 *
10710 * There may also be an implicit trim operation if the file system
10711 * is mounted with -odiscard. The same protections must remain
10712 * in place until the extents have been discarded completely when
10713 * the transaction commit has completed.
10714 */
10715 remove_em = (atomic_read(&block_group->trimming) == 0);
10716 /*
10717 * Make sure a trimmer task always sees the em in the pinned_chunks list
10718 * if it sees block_group->removed == 1 (needs to lock block_group->lock
10719 * before checking block_group->removed).
10720 */
10721 if (!remove_em) {
10722 /*
10723 * Our em might be in trans->transaction->pending_chunks which
10724 * is protected by fs_info->chunk_mutex ([lock|unlock]_chunks),
10725 * and so is the fs_info->pinned_chunks list.
10726 *
10727 * So at this point we must be holding the chunk_mutex to avoid
10728 * any races with chunk allocation (more specifically at
10729 * volumes.c:contains_pending_extent()), to ensure it always
10730 * sees the em, either in the pending_chunks list or in the
10731 * pinned_chunks list.
10732 */
10733 list_move_tail(&em->list, &root->fs_info->pinned_chunks);
10734 }
10735 spin_unlock(&block_group->lock);
10736
10737 if (remove_em) {
10738 struct extent_map_tree *em_tree;
10739
10740 em_tree = &root->fs_info->mapping_tree.map_tree;
10741 write_lock(&em_tree->lock);
10742 /*
10743 * The em might be in the pending_chunks list, so make sure the
10744 * chunk mutex is locked, since remove_extent_mapping() will
10745 * delete us from that list.
10746 */
10747 remove_extent_mapping(em_tree, em);
10748 write_unlock(&em_tree->lock);
10749 /* once for the tree */
10750 free_extent_map(em);
10751 }
10752
10753 unlock_chunks(root);
10754
10755 ret = remove_block_group_free_space(trans, root->fs_info, block_group);
10756 if (ret)
10757 goto out;
10758
10759 btrfs_put_block_group(block_group);
10760 btrfs_put_block_group(block_group);
10761
10762 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
10763 if (ret > 0)
10764 ret = -EIO;
10765 if (ret < 0)
10766 goto out;
10767
10768 ret = btrfs_del_item(trans, root, path);
10769 out:
10770 btrfs_free_path(path);
10771 return ret;
10772 }
10773
10774 struct btrfs_trans_handle *
10775 btrfs_start_trans_remove_block_group(struct btrfs_fs_info *fs_info,
10776 const u64 chunk_offset)
10777 {
10778 struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree;
10779 struct extent_map *em;
10780 struct map_lookup *map;
10781 unsigned int num_items;
10782
10783 read_lock(&em_tree->lock);
10784 em = lookup_extent_mapping(em_tree, chunk_offset, 1);
10785 read_unlock(&em_tree->lock);
10786 ASSERT(em && em->start == chunk_offset);
10787
10788 /*
10789 * We need to reserve 3 + N units from the metadata space info in order
10790 * to remove a block group (done at btrfs_remove_chunk() and at
10791 * btrfs_remove_block_group()), which are used for:
10792 *
10793 * 1 unit for adding the free space inode's orphan (located in the tree
10794 * of tree roots).
10795 * 1 unit for deleting the block group item (located in the extent
10796 * tree).
10797 * 1 unit for deleting the free space item (located in tree of tree
10798 * roots).
10799 * N units for deleting N device extent items corresponding to each
10800 * stripe (located in the device tree).
10801 *
10802 * In order to remove a block group we also need to reserve units in the
10803 * system space info in order to update the chunk tree (update one or
10804 * more device items and remove one chunk item), but this is done at
10805 * btrfs_remove_chunk() through a call to check_system_chunk().
10806 */
10807 map = em->map_lookup;
10808 num_items = 3 + map->num_stripes;
10809 free_extent_map(em);
10810
10811 return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
10812 num_items, 1);
10813 }
10814
10815 /*
10816 * Process the unused_bgs list and remove any that don't have any allocated
10817 * space inside of them.
10818 */
10819 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
10820 {
10821 struct btrfs_block_group_cache *block_group;
10822 struct btrfs_space_info *space_info;
10823 struct btrfs_root *root = fs_info->extent_root;
10824 struct btrfs_trans_handle *trans;
10825 int ret = 0;
10826
10827 if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
10828 return;
10829
10830 spin_lock(&fs_info->unused_bgs_lock);
10831 while (!list_empty(&fs_info->unused_bgs)) {
10832 u64 start, end;
10833 int trimming;
10834
10835 block_group = list_first_entry(&fs_info->unused_bgs,
10836 struct btrfs_block_group_cache,
10837 bg_list);
10838 list_del_init(&block_group->bg_list);
10839
10840 space_info = block_group->space_info;
10841
10842 if (ret || btrfs_mixed_space_info(space_info)) {
10843 btrfs_put_block_group(block_group);
10844 continue;
10845 }
10846 spin_unlock(&fs_info->unused_bgs_lock);
10847
10848 mutex_lock(&fs_info->delete_unused_bgs_mutex);
10849
10850 /* Don't want to race with allocators so take the groups_sem */
10851 down_write(&space_info->groups_sem);
10852 spin_lock(&block_group->lock);
10853 if (block_group->reserved ||
10854 btrfs_block_group_used(&block_group->item) ||
10855 block_group->ro ||
10856 list_is_singular(&block_group->list)) {
10857 /*
10858 * We want to bail if we made new allocations or have
10859 * outstanding allocations in this block group. We do
10860 * the ro check in case balance is currently acting on
10861 * this block group.
10862 */
10863 spin_unlock(&block_group->lock);
10864 up_write(&space_info->groups_sem);
10865 goto next;
10866 }
10867 spin_unlock(&block_group->lock);
10868
10869 /* We don't want to force the issue, only flip if it's ok. */
10870 ret = inc_block_group_ro(block_group, 0);
10871 up_write(&space_info->groups_sem);
10872 if (ret < 0) {
10873 ret = 0;
10874 goto next;
10875 }
10876
10877 /*
10878 * Want to do this before we do anything else so we can recover
10879 * properly if we fail to join the transaction.
10880 */
10881 trans = btrfs_start_trans_remove_block_group(fs_info,
10882 block_group->key.objectid);
10883 if (IS_ERR(trans)) {
10884 btrfs_dec_block_group_ro(root, block_group);
10885 ret = PTR_ERR(trans);
10886 goto next;
10887 }
10888
10889 /*
10890 * We could have pending pinned extents for this block group,
10891 * just delete them, we don't care about them anymore.
10892 */
10893 start = block_group->key.objectid;
10894 end = start + block_group->key.offset - 1;
10895 /*
10896 * Hold the unused_bg_unpin_mutex lock to avoid racing with
10897 * btrfs_finish_extent_commit(). If we are at transaction N,
10898 * another task might be running finish_extent_commit() for the
10899 * previous transaction N - 1, and have seen a range belonging
10900 * to the block group in freed_extents[] before we were able to
10901 * clear the whole block group range from freed_extents[]. This
10902 * means that task can lookup for the block group after we
10903 * unpinned it from freed_extents[] and removed it, leading to
10904 * a BUG_ON() at btrfs_unpin_extent_range().
10905 */
10906 mutex_lock(&fs_info->unused_bg_unpin_mutex);
10907 ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
10908 EXTENT_DIRTY);
10909 if (ret) {
10910 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10911 btrfs_dec_block_group_ro(root, block_group);
10912 goto end_trans;
10913 }
10914 ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
10915 EXTENT_DIRTY);
10916 if (ret) {
10917 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10918 btrfs_dec_block_group_ro(root, block_group);
10919 goto end_trans;
10920 }
10921 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10922
10923 /* Reset pinned so btrfs_put_block_group doesn't complain */
10924 spin_lock(&space_info->lock);
10925 spin_lock(&block_group->lock);
10926
10927 space_info->bytes_pinned -= block_group->pinned;
10928 space_info->bytes_readonly += block_group->pinned;
10929 percpu_counter_add(&space_info->total_bytes_pinned,
10930 -block_group->pinned);
10931 block_group->pinned = 0;
10932
10933 spin_unlock(&block_group->lock);
10934 spin_unlock(&space_info->lock);
10935
10936 /* DISCARD can flip during remount */
10937 trimming = btrfs_test_opt(root->fs_info, DISCARD);
10938
10939 /* Implicit trim during transaction commit. */
10940 if (trimming)
10941 btrfs_get_block_group_trimming(block_group);
10942
10943 /*
10944 * Btrfs_remove_chunk will abort the transaction if things go
10945 * horribly wrong.
10946 */
10947 ret = btrfs_remove_chunk(trans, root,
10948 block_group->key.objectid);
10949
10950 if (ret) {
10951 if (trimming)
10952 btrfs_put_block_group_trimming(block_group);
10953 goto end_trans;
10954 }
10955
10956 /*
10957 * If we're not mounted with -odiscard, we can just forget
10958 * about this block group. Otherwise we'll need to wait
10959 * until transaction commit to do the actual discard.
10960 */
10961 if (trimming) {
10962 spin_lock(&fs_info->unused_bgs_lock);
10963 /*
10964 * A concurrent scrub might have added us to the list
10965 * fs_info->unused_bgs, so use a list_move operation
10966 * to add the block group to the deleted_bgs list.
10967 */
10968 list_move(&block_group->bg_list,
10969 &trans->transaction->deleted_bgs);
10970 spin_unlock(&fs_info->unused_bgs_lock);
10971 btrfs_get_block_group(block_group);
10972 }
10973 end_trans:
10974 btrfs_end_transaction(trans, root);
10975 next:
10976 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
10977 btrfs_put_block_group(block_group);
10978 spin_lock(&fs_info->unused_bgs_lock);
10979 }
10980 spin_unlock(&fs_info->unused_bgs_lock);
10981 }
10982
10983 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
10984 {
10985 struct btrfs_space_info *space_info;
10986 struct btrfs_super_block *disk_super;
10987 u64 features;
10988 u64 flags;
10989 int mixed = 0;
10990 int ret;
10991
10992 disk_super = fs_info->super_copy;
10993 if (!btrfs_super_root(disk_super))
10994 return -EINVAL;
10995
10996 features = btrfs_super_incompat_flags(disk_super);
10997 if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
10998 mixed = 1;
10999
11000 flags = BTRFS_BLOCK_GROUP_SYSTEM;
11001 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
11002 if (ret)
11003 goto out;
11004
11005 if (mixed) {
11006 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
11007 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
11008 } else {
11009 flags = BTRFS_BLOCK_GROUP_METADATA;
11010 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
11011 if (ret)
11012 goto out;
11013
11014 flags = BTRFS_BLOCK_GROUP_DATA;
11015 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
11016 }
11017 out:
11018 return ret;
11019 }
11020
11021 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
11022 {
11023 return unpin_extent_range(root, start, end, false);
11024 }
11025
11026 /*
11027 * It used to be that old block groups would be left around forever.
11028 * Iterating over them would be enough to trim unused space. Since we
11029 * now automatically remove them, we also need to iterate over unallocated
11030 * space.
11031 *
11032 * We don't want a transaction for this since the discard may take a
11033 * substantial amount of time. We don't require that a transaction be
11034 * running, but we do need to take a running transaction into account
11035 * to ensure that we're not discarding chunks that were released in
11036 * the current transaction.
11037 *
11038 * Holding the chunks lock will prevent other threads from allocating
11039 * or releasing chunks, but it won't prevent a running transaction
11040 * from committing and releasing the memory that the pending chunks
11041 * list head uses. For that, we need to take a reference to the
11042 * transaction.
11043 */
11044 static int btrfs_trim_free_extents(struct btrfs_device *device,
11045 u64 minlen, u64 *trimmed)
11046 {
11047 u64 start = 0, len = 0;
11048 int ret;
11049
11050 *trimmed = 0;
11051
11052 /* Not writeable = nothing to do. */
11053 if (!device->writeable)
11054 return 0;
11055
11056 /* No free space = nothing to do. */
11057 if (device->total_bytes <= device->bytes_used)
11058 return 0;
11059
11060 ret = 0;
11061
11062 while (1) {
11063 struct btrfs_fs_info *fs_info = device->dev_root->fs_info;
11064 struct btrfs_transaction *trans;
11065 u64 bytes;
11066
11067 ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
11068 if (ret)
11069 return ret;
11070
11071 down_read(&fs_info->commit_root_sem);
11072
11073 spin_lock(&fs_info->trans_lock);
11074 trans = fs_info->running_transaction;
11075 if (trans)
11076 atomic_inc(&trans->use_count);
11077 spin_unlock(&fs_info->trans_lock);
11078
11079 ret = find_free_dev_extent_start(trans, device, minlen, start,
11080 &start, &len);
11081 if (trans)
11082 btrfs_put_transaction(trans);
11083
11084 if (ret) {
11085 up_read(&fs_info->commit_root_sem);
11086 mutex_unlock(&fs_info->chunk_mutex);
11087 if (ret == -ENOSPC)
11088 ret = 0;
11089 break;
11090 }
11091
11092 ret = btrfs_issue_discard(device->bdev, start, len, &bytes);
11093 up_read(&fs_info->commit_root_sem);
11094 mutex_unlock(&fs_info->chunk_mutex);
11095
11096 if (ret)
11097 break;
11098
11099 start += len;
11100 *trimmed += bytes;
11101
11102 if (fatal_signal_pending(current)) {
11103 ret = -ERESTARTSYS;
11104 break;
11105 }
11106
11107 cond_resched();
11108 }
11109
11110 return ret;
11111 }
11112
11113 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
11114 {
11115 struct btrfs_fs_info *fs_info = root->fs_info;
11116 struct btrfs_block_group_cache *cache = NULL;
11117 struct btrfs_device *device;
11118 struct list_head *devices;
11119 u64 group_trimmed;
11120 u64 start;
11121 u64 end;
11122 u64 trimmed = 0;
11123 u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
11124 int ret = 0;
11125
11126 /*
11127 * try to trim all FS space, our block group may start from non-zero.
11128 */
11129 if (range->len == total_bytes)
11130 cache = btrfs_lookup_first_block_group(fs_info, range->start);
11131 else
11132 cache = btrfs_lookup_block_group(fs_info, range->start);
11133
11134 while (cache) {
11135 if (cache->key.objectid >= (range->start + range->len)) {
11136 btrfs_put_block_group(cache);
11137 break;
11138 }
11139
11140 start = max(range->start, cache->key.objectid);
11141 end = min(range->start + range->len,
11142 cache->key.objectid + cache->key.offset);
11143
11144 if (end - start >= range->minlen) {
11145 if (!block_group_cache_done(cache)) {
11146 ret = cache_block_group(cache, 0);
11147 if (ret) {
11148 btrfs_put_block_group(cache);
11149 break;
11150 }
11151 ret = wait_block_group_cache_done(cache);
11152 if (ret) {
11153 btrfs_put_block_group(cache);
11154 break;
11155 }
11156 }
11157 ret = btrfs_trim_block_group(cache,
11158 &group_trimmed,
11159 start,
11160 end,
11161 range->minlen);
11162
11163 trimmed += group_trimmed;
11164 if (ret) {
11165 btrfs_put_block_group(cache);
11166 break;
11167 }
11168 }
11169
11170 cache = next_block_group(fs_info->tree_root, cache);
11171 }
11172
11173 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
11174 devices = &root->fs_info->fs_devices->alloc_list;
11175 list_for_each_entry(device, devices, dev_alloc_list) {
11176 ret = btrfs_trim_free_extents(device, range->minlen,
11177 &group_trimmed);
11178 if (ret)
11179 break;
11180
11181 trimmed += group_trimmed;
11182 }
11183 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
11184
11185 range->len = trimmed;
11186 return ret;
11187 }
11188
11189 /*
11190 * btrfs_{start,end}_write_no_snapshoting() are similar to
11191 * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
11192 * data into the page cache through nocow before the subvolume is snapshoted,
11193 * but flush the data into disk after the snapshot creation, or to prevent
11194 * operations while snapshoting is ongoing and that cause the snapshot to be
11195 * inconsistent (writes followed by expanding truncates for example).
11196 */
11197 void btrfs_end_write_no_snapshoting(struct btrfs_root *root)
11198 {
11199 percpu_counter_dec(&root->subv_writers->counter);
11200 /*
11201 * Make sure counter is updated before we wake up waiters.
11202 */
11203 smp_mb();
11204 if (waitqueue_active(&root->subv_writers->wait))
11205 wake_up(&root->subv_writers->wait);
11206 }
11207
11208 int btrfs_start_write_no_snapshoting(struct btrfs_root *root)
11209 {
11210 if (atomic_read(&root->will_be_snapshoted))
11211 return 0;
11212
11213 percpu_counter_inc(&root->subv_writers->counter);
11214 /*
11215 * Make sure counter is updated before we check for snapshot creation.
11216 */
11217 smp_mb();
11218 if (atomic_read(&root->will_be_snapshoted)) {
11219 btrfs_end_write_no_snapshoting(root);
11220 return 0;
11221 }
11222 return 1;
11223 }
11224
11225 static int wait_snapshoting_atomic_t(atomic_t *a)
11226 {
11227 schedule();
11228 return 0;
11229 }
11230
11231 void btrfs_wait_for_snapshot_creation(struct btrfs_root *root)
11232 {
11233 while (true) {
11234 int ret;
11235
11236 ret = btrfs_start_write_no_snapshoting(root);
11237 if (ret)
11238 break;
11239 wait_on_atomic_t(&root->will_be_snapshoted,
11240 wait_snapshoting_atomic_t,
11241 TASK_UNINTERRUPTIBLE);
11242 }
11243 }
Linux with added FPC-III support