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1/*
2 * Copyright (C) 2009 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
19#include <linux/sched.h>
20#include <linux/slab.h>
21#include <linux/sort.h>
22#include "ctree.h"
23#include "delayed-ref.h"
24#include "transaction.h"
25
26/*
27 * delayed back reference update tracking. For subvolume trees
28 * we queue up extent allocations and backref maintenance for
29 * delayed processing. This avoids deep call chains where we
30 * add extents in the middle of btrfs_search_slot, and it allows
31 * us to buffer up frequently modified backrefs in an rb tree instead
32 * of hammering updates on the extent allocation tree.
33 */
34
35/*
36 * compare two delayed tree backrefs with same bytenr and type
37 */
38static int comp_tree_refs(struct btrfs_delayed_tree_ref *ref2,
39 struct btrfs_delayed_tree_ref *ref1)
40{
41 if (ref1->node.type == BTRFS_TREE_BLOCK_REF_KEY) {
42 if (ref1->root < ref2->root)
43 return -1;
44 if (ref1->root > ref2->root)
45 return 1;
46 } else {
47 if (ref1->parent < ref2->parent)
48 return -1;
49 if (ref1->parent > ref2->parent)
50 return 1;
51 }
52 return 0;
53}
54
55/*
56 * compare two delayed data backrefs with same bytenr and type
57 */
58static int comp_data_refs(struct btrfs_delayed_data_ref *ref2,
59 struct btrfs_delayed_data_ref *ref1)
60{
61 if (ref1->node.type == BTRFS_EXTENT_DATA_REF_KEY) {
62 if (ref1->root < ref2->root)
63 return -1;
64 if (ref1->root > ref2->root)
65 return 1;
66 if (ref1->objectid < ref2->objectid)
67 return -1;
68 if (ref1->objectid > ref2->objectid)
69 return 1;
70 if (ref1->offset < ref2->offset)
71 return -1;
72 if (ref1->offset > ref2->offset)
73 return 1;
74 } else {
75 if (ref1->parent < ref2->parent)
76 return -1;
77 if (ref1->parent > ref2->parent)
78 return 1;
79 }
80 return 0;
81}
82
83/*
84 * entries in the rb tree are ordered by the byte number of the extent,
85 * type of the delayed backrefs and content of delayed backrefs.
86 */
87static int comp_entry(struct btrfs_delayed_ref_node *ref2,
88 struct btrfs_delayed_ref_node *ref1)
89{
90 if (ref1->bytenr < ref2->bytenr)
91 return -1;
92 if (ref1->bytenr > ref2->bytenr)
93 return 1;
94 if (ref1->is_head && ref2->is_head)
95 return 0;
96 if (ref2->is_head)
97 return -1;
98 if (ref1->is_head)
99 return 1;
100 if (ref1->type < ref2->type)
101 return -1;
102 if (ref1->type > ref2->type)
103 return 1;
104 if (ref1->type == BTRFS_TREE_BLOCK_REF_KEY ||
105 ref1->type == BTRFS_SHARED_BLOCK_REF_KEY) {
106 return comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref2),
107 btrfs_delayed_node_to_tree_ref(ref1));
108 } else if (ref1->type == BTRFS_EXTENT_DATA_REF_KEY ||
109 ref1->type == BTRFS_SHARED_DATA_REF_KEY) {
110 return comp_data_refs(btrfs_delayed_node_to_data_ref(ref2),
111 btrfs_delayed_node_to_data_ref(ref1));
112 }
113 BUG();
114 return 0;
115}
116
117/*
118 * insert a new ref into the rbtree. This returns any existing refs
119 * for the same (bytenr,parent) tuple, or NULL if the new node was properly
120 * inserted.
121 */
122static struct btrfs_delayed_ref_node *tree_insert(struct rb_root *root,
123 struct rb_node *node)
124{
125 struct rb_node **p = &root->rb_node;
126 struct rb_node *parent_node = NULL;
127 struct btrfs_delayed_ref_node *entry;
128 struct btrfs_delayed_ref_node *ins;
129 int cmp;
130
131 ins = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
132 while (*p) {
133 parent_node = *p;
134 entry = rb_entry(parent_node, struct btrfs_delayed_ref_node,
135 rb_node);
136
137 cmp = comp_entry(entry, ins);
138 if (cmp < 0)
139 p = &(*p)->rb_left;
140 else if (cmp > 0)
141 p = &(*p)->rb_right;
142 else
143 return entry;
144 }
145
146 rb_link_node(node, parent_node, p);
147 rb_insert_color(node, root);
148 return NULL;
149}
150
151/*
152 * find an head entry based on bytenr. This returns the delayed ref
153 * head if it was able to find one, or NULL if nothing was in that spot
154 */
155static struct btrfs_delayed_ref_node *find_ref_head(struct rb_root *root,
156 u64 bytenr,
157 struct btrfs_delayed_ref_node **last)
158{
159 struct rb_node *n = root->rb_node;
160 struct btrfs_delayed_ref_node *entry;
161 int cmp;
162
163 while (n) {
164 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
165 WARN_ON(!entry->in_tree);
166 if (last)
167 *last = entry;
168
169 if (bytenr < entry->bytenr)
170 cmp = -1;
171 else if (bytenr > entry->bytenr)
172 cmp = 1;
173 else if (!btrfs_delayed_ref_is_head(entry))
174 cmp = 1;
175 else
176 cmp = 0;
177
178 if (cmp < 0)
179 n = n->rb_left;
180 else if (cmp > 0)
181 n = n->rb_right;
182 else
183 return entry;
184 }
185 return NULL;
186}
187
188int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
189 struct btrfs_delayed_ref_head *head)
190{
191 struct btrfs_delayed_ref_root *delayed_refs;
192
193 delayed_refs = &trans->transaction->delayed_refs;
194 assert_spin_locked(&delayed_refs->lock);
195 if (mutex_trylock(&head->mutex))
196 return 0;
197
198 atomic_inc(&head->node.refs);
199 spin_unlock(&delayed_refs->lock);
200
201 mutex_lock(&head->mutex);
202 spin_lock(&delayed_refs->lock);
203 if (!head->node.in_tree) {
204 mutex_unlock(&head->mutex);
205 btrfs_put_delayed_ref(&head->node);
206 return -EAGAIN;
207 }
208 btrfs_put_delayed_ref(&head->node);
209 return 0;
210}
211
212int btrfs_find_ref_cluster(struct btrfs_trans_handle *trans,
213 struct list_head *cluster, u64 start)
214{
215 int count = 0;
216 struct btrfs_delayed_ref_root *delayed_refs;
217 struct rb_node *node;
218 struct btrfs_delayed_ref_node *ref;
219 struct btrfs_delayed_ref_head *head;
220
221 delayed_refs = &trans->transaction->delayed_refs;
222 if (start == 0) {
223 node = rb_first(&delayed_refs->root);
224 } else {
225 ref = NULL;
226 find_ref_head(&delayed_refs->root, start, &ref);
227 if (ref) {
228 struct btrfs_delayed_ref_node *tmp;
229
230 node = rb_prev(&ref->rb_node);
231 while (node) {
232 tmp = rb_entry(node,
233 struct btrfs_delayed_ref_node,
234 rb_node);
235 if (tmp->bytenr < start)
236 break;
237 ref = tmp;
238 node = rb_prev(&ref->rb_node);
239 }
240 node = &ref->rb_node;
241 } else
242 node = rb_first(&delayed_refs->root);
243 }
244again:
245 while (node && count < 32) {
246 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
247 if (btrfs_delayed_ref_is_head(ref)) {
248 head = btrfs_delayed_node_to_head(ref);
249 if (list_empty(&head->cluster)) {
250 list_add_tail(&head->cluster, cluster);
251 delayed_refs->run_delayed_start =
252 head->node.bytenr;
253 count++;
254
255 WARN_ON(delayed_refs->num_heads_ready == 0);
256 delayed_refs->num_heads_ready--;
257 } else if (count) {
258 /* the goal of the clustering is to find extents
259 * that are likely to end up in the same extent
260 * leaf on disk. So, we don't want them spread
261 * all over the tree. Stop now if we've hit
262 * a head that was already in use
263 */
264 break;
265 }
266 }
267 node = rb_next(node);
268 }
269 if (count) {
270 return 0;
271 } else if (start) {
272 /*
273 * we've gone to the end of the rbtree without finding any
274 * clusters. start from the beginning and try again
275 */
276 start = 0;
277 node = rb_first(&delayed_refs->root);
278 goto again;
279 }
280 return 1;
281}
282
283/*
284 * helper function to update an extent delayed ref in the
285 * rbtree. existing and update must both have the same
286 * bytenr and parent
287 *
288 * This may free existing if the update cancels out whatever
289 * operation it was doing.
290 */
291static noinline void
292update_existing_ref(struct btrfs_trans_handle *trans,
293 struct btrfs_delayed_ref_root *delayed_refs,
294 struct btrfs_delayed_ref_node *existing,
295 struct btrfs_delayed_ref_node *update)
296{
297 if (update->action != existing->action) {
298 /*
299 * this is effectively undoing either an add or a
300 * drop. We decrement the ref_mod, and if it goes
301 * down to zero we just delete the entry without
302 * every changing the extent allocation tree.
303 */
304 existing->ref_mod--;
305 if (existing->ref_mod == 0) {
306 rb_erase(&existing->rb_node,
307 &delayed_refs->root);
308 existing->in_tree = 0;
309 btrfs_put_delayed_ref(existing);
310 delayed_refs->num_entries--;
311 if (trans->delayed_ref_updates)
312 trans->delayed_ref_updates--;
313 } else {
314 WARN_ON(existing->type == BTRFS_TREE_BLOCK_REF_KEY ||
315 existing->type == BTRFS_SHARED_BLOCK_REF_KEY);
316 }
317 } else {
318 WARN_ON(existing->type == BTRFS_TREE_BLOCK_REF_KEY ||
319 existing->type == BTRFS_SHARED_BLOCK_REF_KEY);
320 /*
321 * the action on the existing ref matches
322 * the action on the ref we're trying to add.
323 * Bump the ref_mod by one so the backref that
324 * is eventually added/removed has the correct
325 * reference count
326 */
327 existing->ref_mod += update->ref_mod;
328 }
329}
330
331/*
332 * helper function to update the accounting in the head ref
333 * existing and update must have the same bytenr
334 */
335static noinline void
336update_existing_head_ref(struct btrfs_delayed_ref_node *existing,
337 struct btrfs_delayed_ref_node *update)
338{
339 struct btrfs_delayed_ref_head *existing_ref;
340 struct btrfs_delayed_ref_head *ref;
341
342 existing_ref = btrfs_delayed_node_to_head(existing);
343 ref = btrfs_delayed_node_to_head(update);
344 BUG_ON(existing_ref->is_data != ref->is_data);
345
346 if (ref->must_insert_reserved) {
347 /* if the extent was freed and then
348 * reallocated before the delayed ref
349 * entries were processed, we can end up
350 * with an existing head ref without
351 * the must_insert_reserved flag set.
352 * Set it again here
353 */
354 existing_ref->must_insert_reserved = ref->must_insert_reserved;
355
356 /*
357 * update the num_bytes so we make sure the accounting
358 * is done correctly
359 */
360 existing->num_bytes = update->num_bytes;
361
362 }
363
364 if (ref->extent_op) {
365 if (!existing_ref->extent_op) {
366 existing_ref->extent_op = ref->extent_op;
367 } else {
368 if (ref->extent_op->update_key) {
369 memcpy(&existing_ref->extent_op->key,
370 &ref->extent_op->key,
371 sizeof(ref->extent_op->key));
372 existing_ref->extent_op->update_key = 1;
373 }
374 if (ref->extent_op->update_flags) {
375 existing_ref->extent_op->flags_to_set |=
376 ref->extent_op->flags_to_set;
377 existing_ref->extent_op->update_flags = 1;
378 }
379 kfree(ref->extent_op);
380 }
381 }
382 /*
383 * update the reference mod on the head to reflect this new operation
384 */
385 existing->ref_mod += update->ref_mod;
386}
387
388/*
389 * helper function to actually insert a head node into the rbtree.
390 * this does all the dirty work in terms of maintaining the correct
391 * overall modification count.
392 */
393static noinline int add_delayed_ref_head(struct btrfs_trans_handle *trans,
394 struct btrfs_delayed_ref_node *ref,
395 u64 bytenr, u64 num_bytes,
396 int action, int is_data)
397{
398 struct btrfs_delayed_ref_node *existing;
399 struct btrfs_delayed_ref_head *head_ref = NULL;
400 struct btrfs_delayed_ref_root *delayed_refs;
401 int count_mod = 1;
402 int must_insert_reserved = 0;
403
404 /*
405 * the head node stores the sum of all the mods, so dropping a ref
406 * should drop the sum in the head node by one.
407 */
408 if (action == BTRFS_UPDATE_DELAYED_HEAD)
409 count_mod = 0;
410 else if (action == BTRFS_DROP_DELAYED_REF)
411 count_mod = -1;
412
413 /*
414 * BTRFS_ADD_DELAYED_EXTENT means that we need to update
415 * the reserved accounting when the extent is finally added, or
416 * if a later modification deletes the delayed ref without ever
417 * inserting the extent into the extent allocation tree.
418 * ref->must_insert_reserved is the flag used to record
419 * that accounting mods are required.
420 *
421 * Once we record must_insert_reserved, switch the action to
422 * BTRFS_ADD_DELAYED_REF because other special casing is not required.
423 */
424 if (action == BTRFS_ADD_DELAYED_EXTENT)
425 must_insert_reserved = 1;
426 else
427 must_insert_reserved = 0;
428
429 delayed_refs = &trans->transaction->delayed_refs;
430
431 /* first set the basic ref node struct up */
432 atomic_set(&ref->refs, 1);
433 ref->bytenr = bytenr;
434 ref->num_bytes = num_bytes;
435 ref->ref_mod = count_mod;
436 ref->type = 0;
437 ref->action = 0;
438 ref->is_head = 1;
439 ref->in_tree = 1;
440
441 head_ref = btrfs_delayed_node_to_head(ref);
442 head_ref->must_insert_reserved = must_insert_reserved;
443 head_ref->is_data = is_data;
444
445 INIT_LIST_HEAD(&head_ref->cluster);
446 mutex_init(&head_ref->mutex);
447
448 trace_btrfs_delayed_ref_head(ref, head_ref, action);
449
450 existing = tree_insert(&delayed_refs->root, &ref->rb_node);
451
452 if (existing) {
453 update_existing_head_ref(existing, ref);
454 /*
455 * we've updated the existing ref, free the newly
456 * allocated ref
457 */
458 kfree(ref);
459 } else {
460 delayed_refs->num_heads++;
461 delayed_refs->num_heads_ready++;
462 delayed_refs->num_entries++;
463 trans->delayed_ref_updates++;
464 }
465 return 0;
466}
467
468/*
469 * helper to insert a delayed tree ref into the rbtree.
470 */
471static noinline int add_delayed_tree_ref(struct btrfs_trans_handle *trans,
472 struct btrfs_delayed_ref_node *ref,
473 u64 bytenr, u64 num_bytes, u64 parent,
474 u64 ref_root, int level, int action)
475{
476 struct btrfs_delayed_ref_node *existing;
477 struct btrfs_delayed_tree_ref *full_ref;
478 struct btrfs_delayed_ref_root *delayed_refs;
479
480 if (action == BTRFS_ADD_DELAYED_EXTENT)
481 action = BTRFS_ADD_DELAYED_REF;
482
483 delayed_refs = &trans->transaction->delayed_refs;
484
485 /* first set the basic ref node struct up */
486 atomic_set(&ref->refs, 1);
487 ref->bytenr = bytenr;
488 ref->num_bytes = num_bytes;
489 ref->ref_mod = 1;
490 ref->action = action;
491 ref->is_head = 0;
492 ref->in_tree = 1;
493
494 full_ref = btrfs_delayed_node_to_tree_ref(ref);
495 if (parent) {
496 full_ref->parent = parent;
497 ref->type = BTRFS_SHARED_BLOCK_REF_KEY;
498 } else {
499 full_ref->root = ref_root;
500 ref->type = BTRFS_TREE_BLOCK_REF_KEY;
501 }
502 full_ref->level = level;
503
504 trace_btrfs_delayed_tree_ref(ref, full_ref, action);
505
506 existing = tree_insert(&delayed_refs->root, &ref->rb_node);
507
508 if (existing) {
509 update_existing_ref(trans, delayed_refs, existing, ref);
510 /*
511 * we've updated the existing ref, free the newly
512 * allocated ref
513 */
514 kfree(ref);
515 } else {
516 delayed_refs->num_entries++;
517 trans->delayed_ref_updates++;
518 }
519 return 0;
520}
521
522/*
523 * helper to insert a delayed data ref into the rbtree.
524 */
525static noinline int add_delayed_data_ref(struct btrfs_trans_handle *trans,
526 struct btrfs_delayed_ref_node *ref,
527 u64 bytenr, u64 num_bytes, u64 parent,
528 u64 ref_root, u64 owner, u64 offset,
529 int action)
530{
531 struct btrfs_delayed_ref_node *existing;
532 struct btrfs_delayed_data_ref *full_ref;
533 struct btrfs_delayed_ref_root *delayed_refs;
534
535 if (action == BTRFS_ADD_DELAYED_EXTENT)
536 action = BTRFS_ADD_DELAYED_REF;
537
538 delayed_refs = &trans->transaction->delayed_refs;
539
540 /* first set the basic ref node struct up */
541 atomic_set(&ref->refs, 1);
542 ref->bytenr = bytenr;
543 ref->num_bytes = num_bytes;
544 ref->ref_mod = 1;
545 ref->action = action;
546 ref->is_head = 0;
547 ref->in_tree = 1;
548
549 full_ref = btrfs_delayed_node_to_data_ref(ref);
550 if (parent) {
551 full_ref->parent = parent;
552 ref->type = BTRFS_SHARED_DATA_REF_KEY;
553 } else {
554 full_ref->root = ref_root;
555 ref->type = BTRFS_EXTENT_DATA_REF_KEY;
556 }
557 full_ref->objectid = owner;
558 full_ref->offset = offset;
559
560 trace_btrfs_delayed_data_ref(ref, full_ref, action);
561
562 existing = tree_insert(&delayed_refs->root, &ref->rb_node);
563
564 if (existing) {
565 update_existing_ref(trans, delayed_refs, existing, ref);
566 /*
567 * we've updated the existing ref, free the newly
568 * allocated ref
569 */
570 kfree(ref);
571 } else {
572 delayed_refs->num_entries++;
573 trans->delayed_ref_updates++;
574 }
575 return 0;
576}
577
578/*
579 * add a delayed tree ref. This does all of the accounting required
580 * to make sure the delayed ref is eventually processed before this
581 * transaction commits.
582 */
583int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans,
584 u64 bytenr, u64 num_bytes, u64 parent,
585 u64 ref_root, int level, int action,
586 struct btrfs_delayed_extent_op *extent_op)
587{
588 struct btrfs_delayed_tree_ref *ref;
589 struct btrfs_delayed_ref_head *head_ref;
590 struct btrfs_delayed_ref_root *delayed_refs;
591 int ret;
592
593 BUG_ON(extent_op && extent_op->is_data);
594 ref = kmalloc(sizeof(*ref), GFP_NOFS);
595 if (!ref)
596 return -ENOMEM;
597
598 head_ref = kmalloc(sizeof(*head_ref), GFP_NOFS);
599 if (!head_ref) {
600 kfree(ref);
601 return -ENOMEM;
602 }
603
604 head_ref->extent_op = extent_op;
605
606 delayed_refs = &trans->transaction->delayed_refs;
607 spin_lock(&delayed_refs->lock);
608
609 /*
610 * insert both the head node and the new ref without dropping
611 * the spin lock
612 */
613 ret = add_delayed_ref_head(trans, &head_ref->node, bytenr, num_bytes,
614 action, 0);
615 BUG_ON(ret);
616
617 ret = add_delayed_tree_ref(trans, &ref->node, bytenr, num_bytes,
618 parent, ref_root, level, action);
619 BUG_ON(ret);
620 spin_unlock(&delayed_refs->lock);
621 return 0;
622}
623
624/*
625 * add a delayed data ref. it's similar to btrfs_add_delayed_tree_ref.
626 */
627int btrfs_add_delayed_data_ref(struct btrfs_trans_handle *trans,
628 u64 bytenr, u64 num_bytes,
629 u64 parent, u64 ref_root,
630 u64 owner, u64 offset, int action,
631 struct btrfs_delayed_extent_op *extent_op)
632{
633 struct btrfs_delayed_data_ref *ref;
634 struct btrfs_delayed_ref_head *head_ref;
635 struct btrfs_delayed_ref_root *delayed_refs;
636 int ret;
637
638 BUG_ON(extent_op && !extent_op->is_data);
639 ref = kmalloc(sizeof(*ref), GFP_NOFS);
640 if (!ref)
641 return -ENOMEM;
642
643 head_ref = kmalloc(sizeof(*head_ref), GFP_NOFS);
644 if (!head_ref) {
645 kfree(ref);
646 return -ENOMEM;
647 }
648
649 head_ref->extent_op = extent_op;
650
651 delayed_refs = &trans->transaction->delayed_refs;
652 spin_lock(&delayed_refs->lock);
653
654 /*
655 * insert both the head node and the new ref without dropping
656 * the spin lock
657 */
658 ret = add_delayed_ref_head(trans, &head_ref->node, bytenr, num_bytes,
659 action, 1);
660 BUG_ON(ret);
661
662 ret = add_delayed_data_ref(trans, &ref->node, bytenr, num_bytes,
663 parent, ref_root, owner, offset, action);
664 BUG_ON(ret);
665 spin_unlock(&delayed_refs->lock);
666 return 0;
667}
668
669int btrfs_add_delayed_extent_op(struct btrfs_trans_handle *trans,
670 u64 bytenr, u64 num_bytes,
671 struct btrfs_delayed_extent_op *extent_op)
672{
673 struct btrfs_delayed_ref_head *head_ref;
674 struct btrfs_delayed_ref_root *delayed_refs;
675 int ret;
676
677 head_ref = kmalloc(sizeof(*head_ref), GFP_NOFS);
678 if (!head_ref)
679 return -ENOMEM;
680
681 head_ref->extent_op = extent_op;
682
683 delayed_refs = &trans->transaction->delayed_refs;
684 spin_lock(&delayed_refs->lock);
685
686 ret = add_delayed_ref_head(trans, &head_ref->node, bytenr,
687 num_bytes, BTRFS_UPDATE_DELAYED_HEAD,
688 extent_op->is_data);
689 BUG_ON(ret);
690
691 spin_unlock(&delayed_refs->lock);
692 return 0;
693}
694
695/*
696 * this does a simple search for the head node for a given extent.
697 * It must be called with the delayed ref spinlock held, and it returns
698 * the head node if any where found, or NULL if not.
699 */
700struct btrfs_delayed_ref_head *
701btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr)
702{
703 struct btrfs_delayed_ref_node *ref;
704 struct btrfs_delayed_ref_root *delayed_refs;
705
706 delayed_refs = &trans->transaction->delayed_refs;
707 ref = find_ref_head(&delayed_refs->root, bytenr, NULL);
708 if (ref)
709 return btrfs_delayed_node_to_head(ref);
710 return NULL;
711}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2009 Oracle. All rights reserved.
4 */
5
6#include <linux/sched.h>
7#include <linux/slab.h>
8#include <linux/sort.h>
9#include "messages.h"
10#include "ctree.h"
11#include "delayed-ref.h"
12#include "extent-tree.h"
13#include "transaction.h"
14#include "qgroup.h"
15#include "space-info.h"
16#include "tree-mod-log.h"
17#include "fs.h"
18
19struct kmem_cache *btrfs_delayed_ref_head_cachep;
20struct kmem_cache *btrfs_delayed_ref_node_cachep;
21struct kmem_cache *btrfs_delayed_extent_op_cachep;
22/*
23 * delayed back reference update tracking. For subvolume trees
24 * we queue up extent allocations and backref maintenance for
25 * delayed processing. This avoids deep call chains where we
26 * add extents in the middle of btrfs_search_slot, and it allows
27 * us to buffer up frequently modified backrefs in an rb tree instead
28 * of hammering updates on the extent allocation tree.
29 */
30
31bool btrfs_check_space_for_delayed_refs(struct btrfs_fs_info *fs_info)
32{
33 struct btrfs_block_rsv *delayed_refs_rsv = &fs_info->delayed_refs_rsv;
34 struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
35 bool ret = false;
36 u64 reserved;
37
38 spin_lock(&global_rsv->lock);
39 reserved = global_rsv->reserved;
40 spin_unlock(&global_rsv->lock);
41
42 /*
43 * Since the global reserve is just kind of magic we don't really want
44 * to rely on it to save our bacon, so if our size is more than the
45 * delayed_refs_rsv and the global rsv then it's time to think about
46 * bailing.
47 */
48 spin_lock(&delayed_refs_rsv->lock);
49 reserved += delayed_refs_rsv->reserved;
50 if (delayed_refs_rsv->size >= reserved)
51 ret = true;
52 spin_unlock(&delayed_refs_rsv->lock);
53 return ret;
54}
55
56/*
57 * Release a ref head's reservation.
58 *
59 * @fs_info: the filesystem
60 * @nr_refs: number of delayed refs to drop
61 * @nr_csums: number of csum items to drop
62 *
63 * Drops the delayed ref head's count from the delayed refs rsv and free any
64 * excess reservation we had.
65 */
66void btrfs_delayed_refs_rsv_release(struct btrfs_fs_info *fs_info, int nr_refs, int nr_csums)
67{
68 struct btrfs_block_rsv *block_rsv = &fs_info->delayed_refs_rsv;
69 u64 num_bytes;
70 u64 released;
71
72 num_bytes = btrfs_calc_delayed_ref_bytes(fs_info, nr_refs);
73 num_bytes += btrfs_calc_delayed_ref_csum_bytes(fs_info, nr_csums);
74
75 released = btrfs_block_rsv_release(fs_info, block_rsv, num_bytes, NULL);
76 if (released)
77 trace_btrfs_space_reservation(fs_info, "delayed_refs_rsv",
78 0, released, 0);
79}
80
81/*
82 * Adjust the size of the delayed refs rsv.
83 *
84 * This is to be called anytime we may have adjusted trans->delayed_ref_updates
85 * or trans->delayed_ref_csum_deletions, it'll calculate the additional size and
86 * add it to the delayed_refs_rsv.
87 */
88void btrfs_update_delayed_refs_rsv(struct btrfs_trans_handle *trans)
89{
90 struct btrfs_fs_info *fs_info = trans->fs_info;
91 struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_refs_rsv;
92 struct btrfs_block_rsv *local_rsv = &trans->delayed_rsv;
93 u64 num_bytes;
94 u64 reserved_bytes;
95
96 num_bytes = btrfs_calc_delayed_ref_bytes(fs_info, trans->delayed_ref_updates);
97 num_bytes += btrfs_calc_delayed_ref_csum_bytes(fs_info,
98 trans->delayed_ref_csum_deletions);
99
100 if (num_bytes == 0)
101 return;
102
103 /*
104 * Try to take num_bytes from the transaction's local delayed reserve.
105 * If not possible, try to take as much as it's available. If the local
106 * reserve doesn't have enough reserved space, the delayed refs reserve
107 * will be refilled next time btrfs_delayed_refs_rsv_refill() is called
108 * by someone or if a transaction commit is triggered before that, the
109 * global block reserve will be used. We want to minimize using the
110 * global block reserve for cases we can account for in advance, to
111 * avoid exhausting it and reach -ENOSPC during a transaction commit.
112 */
113 spin_lock(&local_rsv->lock);
114 reserved_bytes = min(num_bytes, local_rsv->reserved);
115 local_rsv->reserved -= reserved_bytes;
116 local_rsv->full = (local_rsv->reserved >= local_rsv->size);
117 spin_unlock(&local_rsv->lock);
118
119 spin_lock(&delayed_rsv->lock);
120 delayed_rsv->size += num_bytes;
121 delayed_rsv->reserved += reserved_bytes;
122 delayed_rsv->full = (delayed_rsv->reserved >= delayed_rsv->size);
123 spin_unlock(&delayed_rsv->lock);
124 trans->delayed_ref_updates = 0;
125 trans->delayed_ref_csum_deletions = 0;
126}
127
128/*
129 * Adjust the size of the delayed refs block reserve for 1 block group item
130 * insertion, used after allocating a block group.
131 */
132void btrfs_inc_delayed_refs_rsv_bg_inserts(struct btrfs_fs_info *fs_info)
133{
134 struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_refs_rsv;
135
136 spin_lock(&delayed_rsv->lock);
137 /*
138 * Inserting a block group item does not require changing the free space
139 * tree, only the extent tree or the block group tree, so this is all we
140 * need.
141 */
142 delayed_rsv->size += btrfs_calc_insert_metadata_size(fs_info, 1);
143 delayed_rsv->full = false;
144 spin_unlock(&delayed_rsv->lock);
145}
146
147/*
148 * Adjust the size of the delayed refs block reserve to release space for 1
149 * block group item insertion.
150 */
151void btrfs_dec_delayed_refs_rsv_bg_inserts(struct btrfs_fs_info *fs_info)
152{
153 struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_refs_rsv;
154 const u64 num_bytes = btrfs_calc_insert_metadata_size(fs_info, 1);
155 u64 released;
156
157 released = btrfs_block_rsv_release(fs_info, delayed_rsv, num_bytes, NULL);
158 if (released > 0)
159 trace_btrfs_space_reservation(fs_info, "delayed_refs_rsv",
160 0, released, 0);
161}
162
163/*
164 * Adjust the size of the delayed refs block reserve for 1 block group item
165 * update.
166 */
167void btrfs_inc_delayed_refs_rsv_bg_updates(struct btrfs_fs_info *fs_info)
168{
169 struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_refs_rsv;
170
171 spin_lock(&delayed_rsv->lock);
172 /*
173 * Updating a block group item does not result in new nodes/leaves and
174 * does not require changing the free space tree, only the extent tree
175 * or the block group tree, so this is all we need.
176 */
177 delayed_rsv->size += btrfs_calc_metadata_size(fs_info, 1);
178 delayed_rsv->full = false;
179 spin_unlock(&delayed_rsv->lock);
180}
181
182/*
183 * Adjust the size of the delayed refs block reserve to release space for 1
184 * block group item update.
185 */
186void btrfs_dec_delayed_refs_rsv_bg_updates(struct btrfs_fs_info *fs_info)
187{
188 struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_refs_rsv;
189 const u64 num_bytes = btrfs_calc_metadata_size(fs_info, 1);
190 u64 released;
191
192 released = btrfs_block_rsv_release(fs_info, delayed_rsv, num_bytes, NULL);
193 if (released > 0)
194 trace_btrfs_space_reservation(fs_info, "delayed_refs_rsv",
195 0, released, 0);
196}
197
198/*
199 * Refill based on our delayed refs usage.
200 *
201 * @fs_info: the filesystem
202 * @flush: control how we can flush for this reservation.
203 *
204 * This will refill the delayed block_rsv up to 1 items size worth of space and
205 * will return -ENOSPC if we can't make the reservation.
206 */
207int btrfs_delayed_refs_rsv_refill(struct btrfs_fs_info *fs_info,
208 enum btrfs_reserve_flush_enum flush)
209{
210 struct btrfs_block_rsv *block_rsv = &fs_info->delayed_refs_rsv;
211 struct btrfs_space_info *space_info = block_rsv->space_info;
212 u64 limit = btrfs_calc_delayed_ref_bytes(fs_info, 1);
213 u64 num_bytes = 0;
214 u64 refilled_bytes;
215 u64 to_free;
216 int ret = -ENOSPC;
217
218 spin_lock(&block_rsv->lock);
219 if (block_rsv->reserved < block_rsv->size) {
220 num_bytes = block_rsv->size - block_rsv->reserved;
221 num_bytes = min(num_bytes, limit);
222 }
223 spin_unlock(&block_rsv->lock);
224
225 if (!num_bytes)
226 return 0;
227
228 ret = btrfs_reserve_metadata_bytes(fs_info, space_info, num_bytes, flush);
229 if (ret)
230 return ret;
231
232 /*
233 * We may have raced with someone else, so check again if we the block
234 * reserve is still not full and release any excess space.
235 */
236 spin_lock(&block_rsv->lock);
237 if (block_rsv->reserved < block_rsv->size) {
238 u64 needed = block_rsv->size - block_rsv->reserved;
239
240 if (num_bytes >= needed) {
241 block_rsv->reserved += needed;
242 block_rsv->full = true;
243 to_free = num_bytes - needed;
244 refilled_bytes = needed;
245 } else {
246 block_rsv->reserved += num_bytes;
247 to_free = 0;
248 refilled_bytes = num_bytes;
249 }
250 } else {
251 to_free = num_bytes;
252 refilled_bytes = 0;
253 }
254 spin_unlock(&block_rsv->lock);
255
256 if (to_free > 0)
257 btrfs_space_info_free_bytes_may_use(fs_info, space_info, to_free);
258
259 if (refilled_bytes > 0)
260 trace_btrfs_space_reservation(fs_info, "delayed_refs_rsv", 0,
261 refilled_bytes, 1);
262 return 0;
263}
264
265/*
266 * compare two delayed data backrefs with same bytenr and type
267 */
268static int comp_data_refs(struct btrfs_delayed_ref_node *ref1,
269 struct btrfs_delayed_ref_node *ref2)
270{
271 if (ref1->data_ref.objectid < ref2->data_ref.objectid)
272 return -1;
273 if (ref1->data_ref.objectid > ref2->data_ref.objectid)
274 return 1;
275 if (ref1->data_ref.offset < ref2->data_ref.offset)
276 return -1;
277 if (ref1->data_ref.offset > ref2->data_ref.offset)
278 return 1;
279 return 0;
280}
281
282static int comp_refs(struct btrfs_delayed_ref_node *ref1,
283 struct btrfs_delayed_ref_node *ref2,
284 bool check_seq)
285{
286 int ret = 0;
287
288 if (ref1->type < ref2->type)
289 return -1;
290 if (ref1->type > ref2->type)
291 return 1;
292 if (ref1->type == BTRFS_SHARED_BLOCK_REF_KEY ||
293 ref1->type == BTRFS_SHARED_DATA_REF_KEY) {
294 if (ref1->parent < ref2->parent)
295 return -1;
296 if (ref1->parent > ref2->parent)
297 return 1;
298 } else {
299 if (ref1->ref_root < ref2->ref_root)
300 return -1;
301 if (ref1->ref_root > ref2->ref_root)
302 return 1;
303 if (ref1->type == BTRFS_EXTENT_DATA_REF_KEY)
304 ret = comp_data_refs(ref1, ref2);
305 }
306 if (ret)
307 return ret;
308 if (check_seq) {
309 if (ref1->seq < ref2->seq)
310 return -1;
311 if (ref1->seq > ref2->seq)
312 return 1;
313 }
314 return 0;
315}
316
317static struct btrfs_delayed_ref_node* tree_insert(struct rb_root_cached *root,
318 struct btrfs_delayed_ref_node *ins)
319{
320 struct rb_node **p = &root->rb_root.rb_node;
321 struct rb_node *node = &ins->ref_node;
322 struct rb_node *parent_node = NULL;
323 struct btrfs_delayed_ref_node *entry;
324 bool leftmost = true;
325
326 while (*p) {
327 int comp;
328
329 parent_node = *p;
330 entry = rb_entry(parent_node, struct btrfs_delayed_ref_node,
331 ref_node);
332 comp = comp_refs(ins, entry, true);
333 if (comp < 0) {
334 p = &(*p)->rb_left;
335 } else if (comp > 0) {
336 p = &(*p)->rb_right;
337 leftmost = false;
338 } else {
339 return entry;
340 }
341 }
342
343 rb_link_node(node, parent_node, p);
344 rb_insert_color_cached(node, root, leftmost);
345 return NULL;
346}
347
348static struct btrfs_delayed_ref_head *find_first_ref_head(
349 struct btrfs_delayed_ref_root *dr)
350{
351 unsigned long from = 0;
352
353 lockdep_assert_held(&dr->lock);
354
355 return xa_find(&dr->head_refs, &from, ULONG_MAX, XA_PRESENT);
356}
357
358static bool btrfs_delayed_ref_lock(struct btrfs_delayed_ref_root *delayed_refs,
359 struct btrfs_delayed_ref_head *head)
360{
361 lockdep_assert_held(&delayed_refs->lock);
362 if (mutex_trylock(&head->mutex))
363 return true;
364
365 refcount_inc(&head->refs);
366 spin_unlock(&delayed_refs->lock);
367
368 mutex_lock(&head->mutex);
369 spin_lock(&delayed_refs->lock);
370 if (!head->tracked) {
371 mutex_unlock(&head->mutex);
372 btrfs_put_delayed_ref_head(head);
373 return false;
374 }
375 btrfs_put_delayed_ref_head(head);
376 return true;
377}
378
379static inline void drop_delayed_ref(struct btrfs_fs_info *fs_info,
380 struct btrfs_delayed_ref_root *delayed_refs,
381 struct btrfs_delayed_ref_head *head,
382 struct btrfs_delayed_ref_node *ref)
383{
384 lockdep_assert_held(&head->lock);
385 rb_erase_cached(&ref->ref_node, &head->ref_tree);
386 RB_CLEAR_NODE(&ref->ref_node);
387 if (!list_empty(&ref->add_list))
388 list_del(&ref->add_list);
389 btrfs_put_delayed_ref(ref);
390 btrfs_delayed_refs_rsv_release(fs_info, 1, 0);
391}
392
393static bool merge_ref(struct btrfs_fs_info *fs_info,
394 struct btrfs_delayed_ref_root *delayed_refs,
395 struct btrfs_delayed_ref_head *head,
396 struct btrfs_delayed_ref_node *ref,
397 u64 seq)
398{
399 struct btrfs_delayed_ref_node *next;
400 struct rb_node *node = rb_next(&ref->ref_node);
401 bool done = false;
402
403 while (!done && node) {
404 int mod;
405
406 next = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
407 node = rb_next(node);
408 if (seq && next->seq >= seq)
409 break;
410 if (comp_refs(ref, next, false))
411 break;
412
413 if (ref->action == next->action) {
414 mod = next->ref_mod;
415 } else {
416 if (ref->ref_mod < next->ref_mod) {
417 swap(ref, next);
418 done = true;
419 }
420 mod = -next->ref_mod;
421 }
422
423 drop_delayed_ref(fs_info, delayed_refs, head, next);
424 ref->ref_mod += mod;
425 if (ref->ref_mod == 0) {
426 drop_delayed_ref(fs_info, delayed_refs, head, ref);
427 done = true;
428 } else {
429 /*
430 * Can't have multiples of the same ref on a tree block.
431 */
432 WARN_ON(ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
433 ref->type == BTRFS_SHARED_BLOCK_REF_KEY);
434 }
435 }
436
437 return done;
438}
439
440void btrfs_merge_delayed_refs(struct btrfs_fs_info *fs_info,
441 struct btrfs_delayed_ref_root *delayed_refs,
442 struct btrfs_delayed_ref_head *head)
443{
444 struct btrfs_delayed_ref_node *ref;
445 struct rb_node *node;
446 u64 seq = 0;
447
448 lockdep_assert_held(&head->lock);
449
450 if (RB_EMPTY_ROOT(&head->ref_tree.rb_root))
451 return;
452
453 /* We don't have too many refs to merge for data. */
454 if (head->is_data)
455 return;
456
457 seq = btrfs_tree_mod_log_lowest_seq(fs_info);
458again:
459 for (node = rb_first_cached(&head->ref_tree); node;
460 node = rb_next(node)) {
461 ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
462 if (seq && ref->seq >= seq)
463 continue;
464 if (merge_ref(fs_info, delayed_refs, head, ref, seq))
465 goto again;
466 }
467}
468
469int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info, u64 seq)
470{
471 int ret = 0;
472 u64 min_seq = btrfs_tree_mod_log_lowest_seq(fs_info);
473
474 if (min_seq != 0 && seq >= min_seq) {
475 btrfs_debug(fs_info,
476 "holding back delayed_ref %llu, lowest is %llu",
477 seq, min_seq);
478 ret = 1;
479 }
480
481 return ret;
482}
483
484struct btrfs_delayed_ref_head *btrfs_select_ref_head(
485 const struct btrfs_fs_info *fs_info,
486 struct btrfs_delayed_ref_root *delayed_refs)
487{
488 struct btrfs_delayed_ref_head *head;
489 unsigned long start_index;
490 unsigned long found_index;
491 bool found_head = false;
492 bool locked;
493
494 spin_lock(&delayed_refs->lock);
495again:
496 start_index = (delayed_refs->run_delayed_start >> fs_info->sectorsize_bits);
497 xa_for_each_start(&delayed_refs->head_refs, found_index, head, start_index) {
498 if (!head->processing) {
499 found_head = true;
500 break;
501 }
502 }
503 if (!found_head) {
504 if (delayed_refs->run_delayed_start == 0) {
505 spin_unlock(&delayed_refs->lock);
506 return NULL;
507 }
508 delayed_refs->run_delayed_start = 0;
509 goto again;
510 }
511
512 head->processing = true;
513 WARN_ON(delayed_refs->num_heads_ready == 0);
514 delayed_refs->num_heads_ready--;
515 delayed_refs->run_delayed_start = head->bytenr +
516 head->num_bytes;
517
518 locked = btrfs_delayed_ref_lock(delayed_refs, head);
519 spin_unlock(&delayed_refs->lock);
520
521 /*
522 * We may have dropped the spin lock to get the head mutex lock, and
523 * that might have given someone else time to free the head. If that's
524 * true, it has been removed from our list and we can move on.
525 */
526 if (!locked)
527 return ERR_PTR(-EAGAIN);
528
529 return head;
530}
531
532void btrfs_unselect_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
533 struct btrfs_delayed_ref_head *head)
534{
535 spin_lock(&delayed_refs->lock);
536 head->processing = false;
537 delayed_refs->num_heads_ready++;
538 spin_unlock(&delayed_refs->lock);
539 btrfs_delayed_ref_unlock(head);
540}
541
542void btrfs_delete_ref_head(const struct btrfs_fs_info *fs_info,
543 struct btrfs_delayed_ref_root *delayed_refs,
544 struct btrfs_delayed_ref_head *head)
545{
546 const unsigned long index = (head->bytenr >> fs_info->sectorsize_bits);
547
548 lockdep_assert_held(&delayed_refs->lock);
549 lockdep_assert_held(&head->lock);
550
551 xa_erase(&delayed_refs->head_refs, index);
552 head->tracked = false;
553 delayed_refs->num_heads--;
554 if (!head->processing)
555 delayed_refs->num_heads_ready--;
556}
557
558/*
559 * Helper to insert the ref_node to the tail or merge with tail.
560 *
561 * Return false if the ref was inserted.
562 * Return true if the ref was merged into an existing one (and therefore can be
563 * freed by the caller).
564 */
565static bool insert_delayed_ref(struct btrfs_trans_handle *trans,
566 struct btrfs_delayed_ref_head *href,
567 struct btrfs_delayed_ref_node *ref)
568{
569 struct btrfs_delayed_ref_root *root = &trans->transaction->delayed_refs;
570 struct btrfs_delayed_ref_node *exist;
571 int mod;
572
573 spin_lock(&href->lock);
574 exist = tree_insert(&href->ref_tree, ref);
575 if (!exist) {
576 if (ref->action == BTRFS_ADD_DELAYED_REF)
577 list_add_tail(&ref->add_list, &href->ref_add_list);
578 spin_unlock(&href->lock);
579 trans->delayed_ref_updates++;
580 return false;
581 }
582
583 /* Now we are sure we can merge */
584 if (exist->action == ref->action) {
585 mod = ref->ref_mod;
586 } else {
587 /* Need to change action */
588 if (exist->ref_mod < ref->ref_mod) {
589 exist->action = ref->action;
590 mod = -exist->ref_mod;
591 exist->ref_mod = ref->ref_mod;
592 if (ref->action == BTRFS_ADD_DELAYED_REF)
593 list_add_tail(&exist->add_list,
594 &href->ref_add_list);
595 else if (ref->action == BTRFS_DROP_DELAYED_REF) {
596 ASSERT(!list_empty(&exist->add_list));
597 list_del_init(&exist->add_list);
598 } else {
599 ASSERT(0);
600 }
601 } else
602 mod = -ref->ref_mod;
603 }
604 exist->ref_mod += mod;
605
606 /* remove existing tail if its ref_mod is zero */
607 if (exist->ref_mod == 0)
608 drop_delayed_ref(trans->fs_info, root, href, exist);
609 spin_unlock(&href->lock);
610 return true;
611}
612
613/*
614 * helper function to update the accounting in the head ref
615 * existing and update must have the same bytenr
616 */
617static noinline void update_existing_head_ref(struct btrfs_trans_handle *trans,
618 struct btrfs_delayed_ref_head *existing,
619 struct btrfs_delayed_ref_head *update)
620{
621 struct btrfs_delayed_ref_root *delayed_refs =
622 &trans->transaction->delayed_refs;
623 struct btrfs_fs_info *fs_info = trans->fs_info;
624 int old_ref_mod;
625
626 BUG_ON(existing->is_data != update->is_data);
627
628 spin_lock(&existing->lock);
629
630 /*
631 * When freeing an extent, we may not know the owning root when we
632 * first create the head_ref. However, some deref before the last deref
633 * will know it, so we just need to update the head_ref accordingly.
634 */
635 if (!existing->owning_root)
636 existing->owning_root = update->owning_root;
637
638 if (update->must_insert_reserved) {
639 /* if the extent was freed and then
640 * reallocated before the delayed ref
641 * entries were processed, we can end up
642 * with an existing head ref without
643 * the must_insert_reserved flag set.
644 * Set it again here
645 */
646 existing->must_insert_reserved = update->must_insert_reserved;
647 existing->owning_root = update->owning_root;
648
649 /*
650 * update the num_bytes so we make sure the accounting
651 * is done correctly
652 */
653 existing->num_bytes = update->num_bytes;
654
655 }
656
657 if (update->extent_op) {
658 if (!existing->extent_op) {
659 existing->extent_op = update->extent_op;
660 } else {
661 if (update->extent_op->update_key) {
662 memcpy(&existing->extent_op->key,
663 &update->extent_op->key,
664 sizeof(update->extent_op->key));
665 existing->extent_op->update_key = true;
666 }
667 if (update->extent_op->update_flags) {
668 existing->extent_op->flags_to_set |=
669 update->extent_op->flags_to_set;
670 existing->extent_op->update_flags = true;
671 }
672 btrfs_free_delayed_extent_op(update->extent_op);
673 }
674 }
675 /*
676 * update the reference mod on the head to reflect this new operation,
677 * only need the lock for this case cause we could be processing it
678 * currently, for refs we just added we know we're a-ok.
679 */
680 old_ref_mod = existing->total_ref_mod;
681 existing->ref_mod += update->ref_mod;
682 existing->total_ref_mod += update->ref_mod;
683
684 /*
685 * If we are going to from a positive ref mod to a negative or vice
686 * versa we need to make sure to adjust pending_csums accordingly.
687 * We reserve bytes for csum deletion when adding or updating a ref head
688 * see add_delayed_ref_head() for more details.
689 */
690 if (existing->is_data) {
691 u64 csum_leaves =
692 btrfs_csum_bytes_to_leaves(fs_info,
693 existing->num_bytes);
694
695 if (existing->total_ref_mod >= 0 && old_ref_mod < 0) {
696 delayed_refs->pending_csums -= existing->num_bytes;
697 btrfs_delayed_refs_rsv_release(fs_info, 0, csum_leaves);
698 }
699 if (existing->total_ref_mod < 0 && old_ref_mod >= 0) {
700 delayed_refs->pending_csums += existing->num_bytes;
701 trans->delayed_ref_csum_deletions += csum_leaves;
702 }
703 }
704
705 spin_unlock(&existing->lock);
706}
707
708static void init_delayed_ref_head(struct btrfs_delayed_ref_head *head_ref,
709 struct btrfs_ref *generic_ref,
710 struct btrfs_qgroup_extent_record *qrecord,
711 u64 reserved)
712{
713 int count_mod = 1;
714 bool must_insert_reserved = false;
715
716 /* If reserved is provided, it must be a data extent. */
717 BUG_ON(generic_ref->type != BTRFS_REF_DATA && reserved);
718
719 switch (generic_ref->action) {
720 case BTRFS_ADD_DELAYED_REF:
721 /* count_mod is already set to 1. */
722 break;
723 case BTRFS_UPDATE_DELAYED_HEAD:
724 count_mod = 0;
725 break;
726 case BTRFS_DROP_DELAYED_REF:
727 /*
728 * The head node stores the sum of all the mods, so dropping a ref
729 * should drop the sum in the head node by one.
730 */
731 count_mod = -1;
732 break;
733 case BTRFS_ADD_DELAYED_EXTENT:
734 /*
735 * BTRFS_ADD_DELAYED_EXTENT means that we need to update the
736 * reserved accounting when the extent is finally added, or if a
737 * later modification deletes the delayed ref without ever
738 * inserting the extent into the extent allocation tree.
739 * ref->must_insert_reserved is the flag used to record that
740 * accounting mods are required.
741 *
742 * Once we record must_insert_reserved, switch the action to
743 * BTRFS_ADD_DELAYED_REF because other special casing is not
744 * required.
745 */
746 must_insert_reserved = true;
747 break;
748 }
749
750 refcount_set(&head_ref->refs, 1);
751 head_ref->bytenr = generic_ref->bytenr;
752 head_ref->num_bytes = generic_ref->num_bytes;
753 head_ref->ref_mod = count_mod;
754 head_ref->reserved_bytes = reserved;
755 head_ref->must_insert_reserved = must_insert_reserved;
756 head_ref->owning_root = generic_ref->owning_root;
757 head_ref->is_data = (generic_ref->type == BTRFS_REF_DATA);
758 head_ref->is_system = (generic_ref->ref_root == BTRFS_CHUNK_TREE_OBJECTID);
759 head_ref->ref_tree = RB_ROOT_CACHED;
760 INIT_LIST_HEAD(&head_ref->ref_add_list);
761 head_ref->tracked = false;
762 head_ref->processing = false;
763 head_ref->total_ref_mod = count_mod;
764 spin_lock_init(&head_ref->lock);
765 mutex_init(&head_ref->mutex);
766
767 /* If not metadata set an impossible level to help debugging. */
768 if (generic_ref->type == BTRFS_REF_METADATA)
769 head_ref->level = generic_ref->tree_ref.level;
770 else
771 head_ref->level = U8_MAX;
772
773 if (qrecord) {
774 if (generic_ref->ref_root && reserved) {
775 qrecord->data_rsv = reserved;
776 qrecord->data_rsv_refroot = generic_ref->ref_root;
777 }
778 qrecord->num_bytes = generic_ref->num_bytes;
779 qrecord->old_roots = NULL;
780 }
781}
782
783/*
784 * helper function to actually insert a head node into the rbtree.
785 * this does all the dirty work in terms of maintaining the correct
786 * overall modification count.
787 *
788 * Returns an error pointer in case of an error.
789 */
790static noinline struct btrfs_delayed_ref_head *
791add_delayed_ref_head(struct btrfs_trans_handle *trans,
792 struct btrfs_delayed_ref_head *head_ref,
793 struct btrfs_qgroup_extent_record *qrecord,
794 int action, bool *qrecord_inserted_ret)
795{
796 struct btrfs_fs_info *fs_info = trans->fs_info;
797 struct btrfs_delayed_ref_head *existing;
798 struct btrfs_delayed_ref_root *delayed_refs;
799 const unsigned long index = (head_ref->bytenr >> fs_info->sectorsize_bits);
800 bool qrecord_inserted = false;
801
802 delayed_refs = &trans->transaction->delayed_refs;
803 lockdep_assert_held(&delayed_refs->lock);
804
805#if BITS_PER_LONG == 32
806 if (head_ref->bytenr >= MAX_LFS_FILESIZE) {
807 if (qrecord)
808 xa_release(&delayed_refs->dirty_extents, index);
809 btrfs_err_rl(fs_info,
810"delayed ref head %llu is beyond 32bit page cache and xarray index limit",
811 head_ref->bytenr);
812 btrfs_err_32bit_limit(fs_info);
813 return ERR_PTR(-EOVERFLOW);
814 }
815#endif
816
817 /* Record qgroup extent info if provided */
818 if (qrecord) {
819 int ret;
820
821 ret = btrfs_qgroup_trace_extent_nolock(fs_info, delayed_refs, qrecord,
822 head_ref->bytenr);
823 if (ret) {
824 /* Clean up if insertion fails or item exists. */
825 xa_release(&delayed_refs->dirty_extents, index);
826 /* Caller responsible for freeing qrecord on error. */
827 if (ret < 0)
828 return ERR_PTR(ret);
829 kfree(qrecord);
830 } else {
831 qrecord_inserted = true;
832 }
833 }
834
835 trace_add_delayed_ref_head(fs_info, head_ref, action);
836
837 existing = xa_load(&delayed_refs->head_refs, index);
838 if (existing) {
839 update_existing_head_ref(trans, existing, head_ref);
840 /*
841 * we've updated the existing ref, free the newly
842 * allocated ref
843 */
844 kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
845 head_ref = existing;
846 } else {
847 existing = xa_store(&delayed_refs->head_refs, index, head_ref, GFP_ATOMIC);
848 if (xa_is_err(existing)) {
849 /* Memory was preallocated by the caller. */
850 ASSERT(xa_err(existing) != -ENOMEM);
851 return ERR_PTR(xa_err(existing));
852 } else if (WARN_ON(existing)) {
853 /*
854 * Shouldn't happen we just did a lookup before under
855 * delayed_refs->lock.
856 */
857 return ERR_PTR(-EEXIST);
858 }
859 head_ref->tracked = true;
860 /*
861 * We reserve the amount of bytes needed to delete csums when
862 * adding the ref head and not when adding individual drop refs
863 * since the csum items are deleted only after running the last
864 * delayed drop ref (the data extent's ref count drops to 0).
865 */
866 if (head_ref->is_data && head_ref->ref_mod < 0) {
867 delayed_refs->pending_csums += head_ref->num_bytes;
868 trans->delayed_ref_csum_deletions +=
869 btrfs_csum_bytes_to_leaves(fs_info, head_ref->num_bytes);
870 }
871 delayed_refs->num_heads++;
872 delayed_refs->num_heads_ready++;
873 }
874 if (qrecord_inserted_ret)
875 *qrecord_inserted_ret = qrecord_inserted;
876
877 return head_ref;
878}
879
880/*
881 * Initialize the structure which represents a modification to a an extent.
882 *
883 * @fs_info: Internal to the mounted filesystem mount structure.
884 *
885 * @ref: The structure which is going to be initialized.
886 *
887 * @bytenr: The logical address of the extent for which a modification is
888 * going to be recorded.
889 *
890 * @num_bytes: Size of the extent whose modification is being recorded.
891 *
892 * @ref_root: The id of the root where this modification has originated, this
893 * can be either one of the well-known metadata trees or the
894 * subvolume id which references this extent.
895 *
896 * @action: Can be one of BTRFS_ADD_DELAYED_REF/BTRFS_DROP_DELAYED_REF or
897 * BTRFS_ADD_DELAYED_EXTENT
898 *
899 * @ref_type: Holds the type of the extent which is being recorded, can be
900 * one of BTRFS_SHARED_BLOCK_REF_KEY/BTRFS_TREE_BLOCK_REF_KEY
901 * when recording a metadata extent or BTRFS_SHARED_DATA_REF_KEY/
902 * BTRFS_EXTENT_DATA_REF_KEY when recording data extent
903 */
904static void init_delayed_ref_common(struct btrfs_fs_info *fs_info,
905 struct btrfs_delayed_ref_node *ref,
906 struct btrfs_ref *generic_ref)
907{
908 int action = generic_ref->action;
909 u64 seq = 0;
910
911 if (action == BTRFS_ADD_DELAYED_EXTENT)
912 action = BTRFS_ADD_DELAYED_REF;
913
914 if (is_fstree(generic_ref->ref_root))
915 seq = atomic64_read(&fs_info->tree_mod_seq);
916
917 refcount_set(&ref->refs, 1);
918 ref->bytenr = generic_ref->bytenr;
919 ref->num_bytes = generic_ref->num_bytes;
920 ref->ref_mod = 1;
921 ref->action = action;
922 ref->seq = seq;
923 ref->type = btrfs_ref_type(generic_ref);
924 ref->ref_root = generic_ref->ref_root;
925 ref->parent = generic_ref->parent;
926 RB_CLEAR_NODE(&ref->ref_node);
927 INIT_LIST_HEAD(&ref->add_list);
928
929 if (generic_ref->type == BTRFS_REF_DATA)
930 ref->data_ref = generic_ref->data_ref;
931 else
932 ref->tree_ref = generic_ref->tree_ref;
933}
934
935void btrfs_init_tree_ref(struct btrfs_ref *generic_ref, int level, u64 mod_root,
936 bool skip_qgroup)
937{
938#ifdef CONFIG_BTRFS_FS_REF_VERIFY
939 /* If @real_root not set, use @root as fallback */
940 generic_ref->real_root = mod_root ?: generic_ref->ref_root;
941#endif
942 generic_ref->tree_ref.level = level;
943 generic_ref->type = BTRFS_REF_METADATA;
944 if (skip_qgroup || !(is_fstree(generic_ref->ref_root) &&
945 (!mod_root || is_fstree(mod_root))))
946 generic_ref->skip_qgroup = true;
947 else
948 generic_ref->skip_qgroup = false;
949
950}
951
952void btrfs_init_data_ref(struct btrfs_ref *generic_ref, u64 ino, u64 offset,
953 u64 mod_root, bool skip_qgroup)
954{
955#ifdef CONFIG_BTRFS_FS_REF_VERIFY
956 /* If @real_root not set, use @root as fallback */
957 generic_ref->real_root = mod_root ?: generic_ref->ref_root;
958#endif
959 generic_ref->data_ref.objectid = ino;
960 generic_ref->data_ref.offset = offset;
961 generic_ref->type = BTRFS_REF_DATA;
962 if (skip_qgroup || !(is_fstree(generic_ref->ref_root) &&
963 (!mod_root || is_fstree(mod_root))))
964 generic_ref->skip_qgroup = true;
965 else
966 generic_ref->skip_qgroup = false;
967}
968
969static int add_delayed_ref(struct btrfs_trans_handle *trans,
970 struct btrfs_ref *generic_ref,
971 struct btrfs_delayed_extent_op *extent_op,
972 u64 reserved)
973{
974 struct btrfs_fs_info *fs_info = trans->fs_info;
975 struct btrfs_delayed_ref_node *node;
976 struct btrfs_delayed_ref_head *head_ref;
977 struct btrfs_delayed_ref_head *new_head_ref;
978 struct btrfs_delayed_ref_root *delayed_refs;
979 struct btrfs_qgroup_extent_record *record = NULL;
980 const unsigned long index = (generic_ref->bytenr >> fs_info->sectorsize_bits);
981 bool qrecord_reserved = false;
982 bool qrecord_inserted;
983 int action = generic_ref->action;
984 bool merged;
985 int ret;
986
987 node = kmem_cache_alloc(btrfs_delayed_ref_node_cachep, GFP_NOFS);
988 if (!node)
989 return -ENOMEM;
990
991 head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
992 if (!head_ref) {
993 ret = -ENOMEM;
994 goto free_node;
995 }
996
997 delayed_refs = &trans->transaction->delayed_refs;
998
999 if (btrfs_qgroup_full_accounting(fs_info) && !generic_ref->skip_qgroup) {
1000 record = kzalloc(sizeof(*record), GFP_NOFS);
1001 if (!record) {
1002 ret = -ENOMEM;
1003 goto free_head_ref;
1004 }
1005 if (xa_reserve(&delayed_refs->dirty_extents, index, GFP_NOFS)) {
1006 ret = -ENOMEM;
1007 goto free_record;
1008 }
1009 qrecord_reserved = true;
1010 }
1011
1012 ret = xa_reserve(&delayed_refs->head_refs, index, GFP_NOFS);
1013 if (ret) {
1014 if (qrecord_reserved)
1015 xa_release(&delayed_refs->dirty_extents, index);
1016 goto free_record;
1017 }
1018
1019 init_delayed_ref_common(fs_info, node, generic_ref);
1020 init_delayed_ref_head(head_ref, generic_ref, record, reserved);
1021 head_ref->extent_op = extent_op;
1022
1023 spin_lock(&delayed_refs->lock);
1024
1025 /*
1026 * insert both the head node and the new ref without dropping
1027 * the spin lock
1028 */
1029 new_head_ref = add_delayed_ref_head(trans, head_ref, record,
1030 action, &qrecord_inserted);
1031 if (IS_ERR(new_head_ref)) {
1032 xa_release(&delayed_refs->head_refs, index);
1033 spin_unlock(&delayed_refs->lock);
1034 ret = PTR_ERR(new_head_ref);
1035 goto free_record;
1036 }
1037 head_ref = new_head_ref;
1038
1039 merged = insert_delayed_ref(trans, head_ref, node);
1040 spin_unlock(&delayed_refs->lock);
1041
1042 /*
1043 * Need to update the delayed_refs_rsv with any changes we may have
1044 * made.
1045 */
1046 btrfs_update_delayed_refs_rsv(trans);
1047
1048 if (generic_ref->type == BTRFS_REF_DATA)
1049 trace_add_delayed_data_ref(trans->fs_info, node);
1050 else
1051 trace_add_delayed_tree_ref(trans->fs_info, node);
1052 if (merged)
1053 kmem_cache_free(btrfs_delayed_ref_node_cachep, node);
1054
1055 if (qrecord_inserted)
1056 return btrfs_qgroup_trace_extent_post(trans, record, generic_ref->bytenr);
1057 return 0;
1058
1059free_record:
1060 kfree(record);
1061free_head_ref:
1062 kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
1063free_node:
1064 kmem_cache_free(btrfs_delayed_ref_node_cachep, node);
1065 return ret;
1066}
1067
1068/*
1069 * Add a delayed tree ref. This does all of the accounting required to make sure
1070 * the delayed ref is eventually processed before this transaction commits.
1071 */
1072int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans,
1073 struct btrfs_ref *generic_ref,
1074 struct btrfs_delayed_extent_op *extent_op)
1075{
1076 ASSERT(generic_ref->type == BTRFS_REF_METADATA && generic_ref->action);
1077 return add_delayed_ref(trans, generic_ref, extent_op, 0);
1078}
1079
1080/*
1081 * add a delayed data ref. it's similar to btrfs_add_delayed_tree_ref.
1082 */
1083int btrfs_add_delayed_data_ref(struct btrfs_trans_handle *trans,
1084 struct btrfs_ref *generic_ref,
1085 u64 reserved)
1086{
1087 ASSERT(generic_ref->type == BTRFS_REF_DATA && generic_ref->action);
1088 return add_delayed_ref(trans, generic_ref, NULL, reserved);
1089}
1090
1091int btrfs_add_delayed_extent_op(struct btrfs_trans_handle *trans,
1092 u64 bytenr, u64 num_bytes, u8 level,
1093 struct btrfs_delayed_extent_op *extent_op)
1094{
1095 const unsigned long index = (bytenr >> trans->fs_info->sectorsize_bits);
1096 struct btrfs_delayed_ref_head *head_ref;
1097 struct btrfs_delayed_ref_head *head_ref_ret;
1098 struct btrfs_delayed_ref_root *delayed_refs;
1099 struct btrfs_ref generic_ref = {
1100 .type = BTRFS_REF_METADATA,
1101 .action = BTRFS_UPDATE_DELAYED_HEAD,
1102 .bytenr = bytenr,
1103 .num_bytes = num_bytes,
1104 .tree_ref.level = level,
1105 };
1106 int ret;
1107
1108 head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
1109 if (!head_ref)
1110 return -ENOMEM;
1111
1112 init_delayed_ref_head(head_ref, &generic_ref, NULL, 0);
1113 head_ref->extent_op = extent_op;
1114
1115 delayed_refs = &trans->transaction->delayed_refs;
1116
1117 ret = xa_reserve(&delayed_refs->head_refs, index, GFP_NOFS);
1118 if (ret) {
1119 kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
1120 return ret;
1121 }
1122
1123 spin_lock(&delayed_refs->lock);
1124 head_ref_ret = add_delayed_ref_head(trans, head_ref, NULL,
1125 BTRFS_UPDATE_DELAYED_HEAD, NULL);
1126 if (IS_ERR(head_ref_ret)) {
1127 xa_release(&delayed_refs->head_refs, index);
1128 spin_unlock(&delayed_refs->lock);
1129 kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
1130 return PTR_ERR(head_ref_ret);
1131 }
1132 spin_unlock(&delayed_refs->lock);
1133
1134 /*
1135 * Need to update the delayed_refs_rsv with any changes we may have
1136 * made.
1137 */
1138 btrfs_update_delayed_refs_rsv(trans);
1139 return 0;
1140}
1141
1142void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
1143{
1144 if (refcount_dec_and_test(&ref->refs)) {
1145 WARN_ON(!RB_EMPTY_NODE(&ref->ref_node));
1146 kmem_cache_free(btrfs_delayed_ref_node_cachep, ref);
1147 }
1148}
1149
1150/*
1151 * This does a simple search for the head node for a given extent. Returns the
1152 * head node if found, or NULL if not.
1153 */
1154struct btrfs_delayed_ref_head *
1155btrfs_find_delayed_ref_head(const struct btrfs_fs_info *fs_info,
1156 struct btrfs_delayed_ref_root *delayed_refs,
1157 u64 bytenr)
1158{
1159 const unsigned long index = (bytenr >> fs_info->sectorsize_bits);
1160
1161 lockdep_assert_held(&delayed_refs->lock);
1162
1163 return xa_load(&delayed_refs->head_refs, index);
1164}
1165
1166static int find_comp(struct btrfs_delayed_ref_node *entry, u64 root, u64 parent)
1167{
1168 int type = parent ? BTRFS_SHARED_BLOCK_REF_KEY : BTRFS_TREE_BLOCK_REF_KEY;
1169
1170 if (type < entry->type)
1171 return -1;
1172 if (type > entry->type)
1173 return 1;
1174
1175 if (type == BTRFS_TREE_BLOCK_REF_KEY) {
1176 if (root < entry->ref_root)
1177 return -1;
1178 if (root > entry->ref_root)
1179 return 1;
1180 } else {
1181 if (parent < entry->parent)
1182 return -1;
1183 if (parent > entry->parent)
1184 return 1;
1185 }
1186 return 0;
1187}
1188
1189/*
1190 * Check to see if a given root/parent reference is attached to the head. This
1191 * only checks for BTRFS_ADD_DELAYED_REF references that match, as that
1192 * indicates the reference exists for the given root or parent. This is for
1193 * tree blocks only.
1194 *
1195 * @head: the head of the bytenr we're searching.
1196 * @root: the root objectid of the reference if it is a normal reference.
1197 * @parent: the parent if this is a shared backref.
1198 */
1199bool btrfs_find_delayed_tree_ref(struct btrfs_delayed_ref_head *head,
1200 u64 root, u64 parent)
1201{
1202 struct rb_node *node;
1203 bool found = false;
1204
1205 lockdep_assert_held(&head->mutex);
1206
1207 spin_lock(&head->lock);
1208 node = head->ref_tree.rb_root.rb_node;
1209 while (node) {
1210 struct btrfs_delayed_ref_node *entry;
1211 int ret;
1212
1213 entry = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
1214 ret = find_comp(entry, root, parent);
1215 if (ret < 0) {
1216 node = node->rb_left;
1217 } else if (ret > 0) {
1218 node = node->rb_right;
1219 } else {
1220 /*
1221 * We only want to count ADD actions, as drops mean the
1222 * ref doesn't exist.
1223 */
1224 if (entry->action == BTRFS_ADD_DELAYED_REF)
1225 found = true;
1226 break;
1227 }
1228 }
1229 spin_unlock(&head->lock);
1230 return found;
1231}
1232
1233void btrfs_destroy_delayed_refs(struct btrfs_transaction *trans)
1234{
1235 struct btrfs_delayed_ref_root *delayed_refs = &trans->delayed_refs;
1236 struct btrfs_fs_info *fs_info = trans->fs_info;
1237
1238 spin_lock(&delayed_refs->lock);
1239 while (true) {
1240 struct btrfs_delayed_ref_head *head;
1241 struct rb_node *n;
1242 bool pin_bytes = false;
1243
1244 head = find_first_ref_head(delayed_refs);
1245 if (!head)
1246 break;
1247
1248 if (!btrfs_delayed_ref_lock(delayed_refs, head))
1249 continue;
1250
1251 spin_lock(&head->lock);
1252 while ((n = rb_first_cached(&head->ref_tree)) != NULL) {
1253 struct btrfs_delayed_ref_node *ref;
1254
1255 ref = rb_entry(n, struct btrfs_delayed_ref_node, ref_node);
1256 drop_delayed_ref(fs_info, delayed_refs, head, ref);
1257 }
1258 if (head->must_insert_reserved)
1259 pin_bytes = true;
1260 btrfs_free_delayed_extent_op(head->extent_op);
1261 btrfs_delete_ref_head(fs_info, delayed_refs, head);
1262 spin_unlock(&head->lock);
1263 spin_unlock(&delayed_refs->lock);
1264 mutex_unlock(&head->mutex);
1265
1266 if (pin_bytes) {
1267 struct btrfs_block_group *bg;
1268
1269 bg = btrfs_lookup_block_group(fs_info, head->bytenr);
1270 if (WARN_ON_ONCE(bg == NULL)) {
1271 /*
1272 * Unexpected and there's nothing we can do here
1273 * because we are in a transaction abort path,
1274 * so any errors can only be ignored or reported
1275 * while attempting to cleanup all resources.
1276 */
1277 btrfs_err(fs_info,
1278"block group for delayed ref at %llu was not found while destroying ref head",
1279 head->bytenr);
1280 } else {
1281 spin_lock(&bg->space_info->lock);
1282 spin_lock(&bg->lock);
1283 bg->pinned += head->num_bytes;
1284 btrfs_space_info_update_bytes_pinned(fs_info,
1285 bg->space_info,
1286 head->num_bytes);
1287 bg->reserved -= head->num_bytes;
1288 bg->space_info->bytes_reserved -= head->num_bytes;
1289 spin_unlock(&bg->lock);
1290 spin_unlock(&bg->space_info->lock);
1291
1292 btrfs_put_block_group(bg);
1293 }
1294
1295 btrfs_error_unpin_extent_range(fs_info, head->bytenr,
1296 head->bytenr + head->num_bytes - 1);
1297 }
1298 btrfs_cleanup_ref_head_accounting(fs_info, delayed_refs, head);
1299 btrfs_put_delayed_ref_head(head);
1300 cond_resched();
1301 spin_lock(&delayed_refs->lock);
1302 }
1303 btrfs_qgroup_destroy_extent_records(trans);
1304
1305 spin_unlock(&delayed_refs->lock);
1306}
1307
1308void __cold btrfs_delayed_ref_exit(void)
1309{
1310 kmem_cache_destroy(btrfs_delayed_ref_head_cachep);
1311 kmem_cache_destroy(btrfs_delayed_ref_node_cachep);
1312 kmem_cache_destroy(btrfs_delayed_extent_op_cachep);
1313}
1314
1315int __init btrfs_delayed_ref_init(void)
1316{
1317 btrfs_delayed_ref_head_cachep = KMEM_CACHE(btrfs_delayed_ref_head, 0);
1318 if (!btrfs_delayed_ref_head_cachep)
1319 goto fail;
1320
1321 btrfs_delayed_ref_node_cachep = KMEM_CACHE(btrfs_delayed_ref_node, 0);
1322 if (!btrfs_delayed_ref_node_cachep)
1323 goto fail;
1324
1325 btrfs_delayed_extent_op_cachep = KMEM_CACHE(btrfs_delayed_extent_op, 0);
1326 if (!btrfs_delayed_extent_op_cachep)
1327 goto fail;
1328
1329 return 0;
1330fail:
1331 btrfs_delayed_ref_exit();
1332 return -ENOMEM;
1333}