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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 "ctree.h"
10#include "delayed-ref.h"
11#include "transaction.h"
12#include "qgroup.h"
13#include "space-info.h"
14
15struct kmem_cache *btrfs_delayed_ref_head_cachep;
16struct kmem_cache *btrfs_delayed_tree_ref_cachep;
17struct kmem_cache *btrfs_delayed_data_ref_cachep;
18struct kmem_cache *btrfs_delayed_extent_op_cachep;
19/*
20 * delayed back reference update tracking. For subvolume trees
21 * we queue up extent allocations and backref maintenance for
22 * delayed processing. This avoids deep call chains where we
23 * add extents in the middle of btrfs_search_slot, and it allows
24 * us to buffer up frequently modified backrefs in an rb tree instead
25 * of hammering updates on the extent allocation tree.
26 */
27
28bool btrfs_check_space_for_delayed_refs(struct btrfs_fs_info *fs_info)
29{
30 struct btrfs_block_rsv *delayed_refs_rsv = &fs_info->delayed_refs_rsv;
31 struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
32 bool ret = false;
33 u64 reserved;
34
35 spin_lock(&global_rsv->lock);
36 reserved = global_rsv->reserved;
37 spin_unlock(&global_rsv->lock);
38
39 /*
40 * Since the global reserve is just kind of magic we don't really want
41 * to rely on it to save our bacon, so if our size is more than the
42 * delayed_refs_rsv and the global rsv then it's time to think about
43 * bailing.
44 */
45 spin_lock(&delayed_refs_rsv->lock);
46 reserved += delayed_refs_rsv->reserved;
47 if (delayed_refs_rsv->size >= reserved)
48 ret = true;
49 spin_unlock(&delayed_refs_rsv->lock);
50 return ret;
51}
52
53int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans)
54{
55 u64 num_entries =
56 atomic_read(&trans->transaction->delayed_refs.num_entries);
57 u64 avg_runtime;
58 u64 val;
59
60 smp_mb();
61 avg_runtime = trans->fs_info->avg_delayed_ref_runtime;
62 val = num_entries * avg_runtime;
63 if (val >= NSEC_PER_SEC)
64 return 1;
65 if (val >= NSEC_PER_SEC / 2)
66 return 2;
67
68 return btrfs_check_space_for_delayed_refs(trans->fs_info);
69}
70
71/**
72 * btrfs_delayed_refs_rsv_release - release a ref head's reservation.
73 * @fs_info - the fs_info for our fs.
74 * @nr - the number of items to drop.
75 *
76 * This drops the delayed ref head's count from the delayed refs rsv and frees
77 * any excess reservation we had.
78 */
79void btrfs_delayed_refs_rsv_release(struct btrfs_fs_info *fs_info, int nr)
80{
81 struct btrfs_block_rsv *block_rsv = &fs_info->delayed_refs_rsv;
82 u64 num_bytes = btrfs_calc_insert_metadata_size(fs_info, nr);
83 u64 released = 0;
84
85 released = btrfs_block_rsv_release(fs_info, block_rsv, num_bytes, NULL);
86 if (released)
87 trace_btrfs_space_reservation(fs_info, "delayed_refs_rsv",
88 0, released, 0);
89}
90
91/*
92 * btrfs_update_delayed_refs_rsv - adjust the size of the delayed refs rsv
93 * @trans - the trans that may have generated delayed refs
94 *
95 * This is to be called anytime we may have adjusted trans->delayed_ref_updates,
96 * it'll calculate the additional size and add it to the delayed_refs_rsv.
97 */
98void btrfs_update_delayed_refs_rsv(struct btrfs_trans_handle *trans)
99{
100 struct btrfs_fs_info *fs_info = trans->fs_info;
101 struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_refs_rsv;
102 u64 num_bytes;
103
104 if (!trans->delayed_ref_updates)
105 return;
106
107 num_bytes = btrfs_calc_insert_metadata_size(fs_info,
108 trans->delayed_ref_updates);
109 spin_lock(&delayed_rsv->lock);
110 delayed_rsv->size += num_bytes;
111 delayed_rsv->full = 0;
112 spin_unlock(&delayed_rsv->lock);
113 trans->delayed_ref_updates = 0;
114}
115
116/**
117 * btrfs_migrate_to_delayed_refs_rsv - transfer bytes to our delayed refs rsv.
118 * @fs_info - the fs info for our fs.
119 * @src - the source block rsv to transfer from.
120 * @num_bytes - the number of bytes to transfer.
121 *
122 * This transfers up to the num_bytes amount from the src rsv to the
123 * delayed_refs_rsv. Any extra bytes are returned to the space info.
124 */
125void btrfs_migrate_to_delayed_refs_rsv(struct btrfs_fs_info *fs_info,
126 struct btrfs_block_rsv *src,
127 u64 num_bytes)
128{
129 struct btrfs_block_rsv *delayed_refs_rsv = &fs_info->delayed_refs_rsv;
130 u64 to_free = 0;
131
132 spin_lock(&src->lock);
133 src->reserved -= num_bytes;
134 src->size -= num_bytes;
135 spin_unlock(&src->lock);
136
137 spin_lock(&delayed_refs_rsv->lock);
138 if (delayed_refs_rsv->size > delayed_refs_rsv->reserved) {
139 u64 delta = delayed_refs_rsv->size -
140 delayed_refs_rsv->reserved;
141 if (num_bytes > delta) {
142 to_free = num_bytes - delta;
143 num_bytes = delta;
144 }
145 } else {
146 to_free = num_bytes;
147 num_bytes = 0;
148 }
149
150 if (num_bytes)
151 delayed_refs_rsv->reserved += num_bytes;
152 if (delayed_refs_rsv->reserved >= delayed_refs_rsv->size)
153 delayed_refs_rsv->full = 1;
154 spin_unlock(&delayed_refs_rsv->lock);
155
156 if (num_bytes)
157 trace_btrfs_space_reservation(fs_info, "delayed_refs_rsv",
158 0, num_bytes, 1);
159 if (to_free)
160 btrfs_space_info_free_bytes_may_use(fs_info,
161 delayed_refs_rsv->space_info, to_free);
162}
163
164/**
165 * btrfs_delayed_refs_rsv_refill - refill based on our delayed refs usage.
166 * @fs_info - the fs_info for our fs.
167 * @flush - control how we can flush for this reservation.
168 *
169 * This will refill the delayed block_rsv up to 1 items size worth of space and
170 * will return -ENOSPC if we can't make the reservation.
171 */
172int btrfs_delayed_refs_rsv_refill(struct btrfs_fs_info *fs_info,
173 enum btrfs_reserve_flush_enum flush)
174{
175 struct btrfs_block_rsv *block_rsv = &fs_info->delayed_refs_rsv;
176 u64 limit = btrfs_calc_insert_metadata_size(fs_info, 1);
177 u64 num_bytes = 0;
178 int ret = -ENOSPC;
179
180 spin_lock(&block_rsv->lock);
181 if (block_rsv->reserved < block_rsv->size) {
182 num_bytes = block_rsv->size - block_rsv->reserved;
183 num_bytes = min(num_bytes, limit);
184 }
185 spin_unlock(&block_rsv->lock);
186
187 if (!num_bytes)
188 return 0;
189
190 ret = btrfs_reserve_metadata_bytes(fs_info->extent_root, block_rsv,
191 num_bytes, flush);
192 if (ret)
193 return ret;
194 btrfs_block_rsv_add_bytes(block_rsv, num_bytes, 0);
195 trace_btrfs_space_reservation(fs_info, "delayed_refs_rsv",
196 0, num_bytes, 1);
197 return 0;
198}
199
200/*
201 * compare two delayed tree backrefs with same bytenr and type
202 */
203static int comp_tree_refs(struct btrfs_delayed_tree_ref *ref1,
204 struct btrfs_delayed_tree_ref *ref2)
205{
206 if (ref1->node.type == BTRFS_TREE_BLOCK_REF_KEY) {
207 if (ref1->root < ref2->root)
208 return -1;
209 if (ref1->root > ref2->root)
210 return 1;
211 } else {
212 if (ref1->parent < ref2->parent)
213 return -1;
214 if (ref1->parent > ref2->parent)
215 return 1;
216 }
217 return 0;
218}
219
220/*
221 * compare two delayed data backrefs with same bytenr and type
222 */
223static int comp_data_refs(struct btrfs_delayed_data_ref *ref1,
224 struct btrfs_delayed_data_ref *ref2)
225{
226 if (ref1->node.type == BTRFS_EXTENT_DATA_REF_KEY) {
227 if (ref1->root < ref2->root)
228 return -1;
229 if (ref1->root > ref2->root)
230 return 1;
231 if (ref1->objectid < ref2->objectid)
232 return -1;
233 if (ref1->objectid > ref2->objectid)
234 return 1;
235 if (ref1->offset < ref2->offset)
236 return -1;
237 if (ref1->offset > ref2->offset)
238 return 1;
239 } else {
240 if (ref1->parent < ref2->parent)
241 return -1;
242 if (ref1->parent > ref2->parent)
243 return 1;
244 }
245 return 0;
246}
247
248static int comp_refs(struct btrfs_delayed_ref_node *ref1,
249 struct btrfs_delayed_ref_node *ref2,
250 bool check_seq)
251{
252 int ret = 0;
253
254 if (ref1->type < ref2->type)
255 return -1;
256 if (ref1->type > ref2->type)
257 return 1;
258 if (ref1->type == BTRFS_TREE_BLOCK_REF_KEY ||
259 ref1->type == BTRFS_SHARED_BLOCK_REF_KEY)
260 ret = comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref1),
261 btrfs_delayed_node_to_tree_ref(ref2));
262 else
263 ret = comp_data_refs(btrfs_delayed_node_to_data_ref(ref1),
264 btrfs_delayed_node_to_data_ref(ref2));
265 if (ret)
266 return ret;
267 if (check_seq) {
268 if (ref1->seq < ref2->seq)
269 return -1;
270 if (ref1->seq > ref2->seq)
271 return 1;
272 }
273 return 0;
274}
275
276/* insert a new ref to head ref rbtree */
277static struct btrfs_delayed_ref_head *htree_insert(struct rb_root_cached *root,
278 struct rb_node *node)
279{
280 struct rb_node **p = &root->rb_root.rb_node;
281 struct rb_node *parent_node = NULL;
282 struct btrfs_delayed_ref_head *entry;
283 struct btrfs_delayed_ref_head *ins;
284 u64 bytenr;
285 bool leftmost = true;
286
287 ins = rb_entry(node, struct btrfs_delayed_ref_head, href_node);
288 bytenr = ins->bytenr;
289 while (*p) {
290 parent_node = *p;
291 entry = rb_entry(parent_node, struct btrfs_delayed_ref_head,
292 href_node);
293
294 if (bytenr < entry->bytenr) {
295 p = &(*p)->rb_left;
296 } else if (bytenr > entry->bytenr) {
297 p = &(*p)->rb_right;
298 leftmost = false;
299 } else {
300 return entry;
301 }
302 }
303
304 rb_link_node(node, parent_node, p);
305 rb_insert_color_cached(node, root, leftmost);
306 return NULL;
307}
308
309static struct btrfs_delayed_ref_node* tree_insert(struct rb_root_cached *root,
310 struct btrfs_delayed_ref_node *ins)
311{
312 struct rb_node **p = &root->rb_root.rb_node;
313 struct rb_node *node = &ins->ref_node;
314 struct rb_node *parent_node = NULL;
315 struct btrfs_delayed_ref_node *entry;
316 bool leftmost = true;
317
318 while (*p) {
319 int comp;
320
321 parent_node = *p;
322 entry = rb_entry(parent_node, struct btrfs_delayed_ref_node,
323 ref_node);
324 comp = comp_refs(ins, entry, true);
325 if (comp < 0) {
326 p = &(*p)->rb_left;
327 } else if (comp > 0) {
328 p = &(*p)->rb_right;
329 leftmost = false;
330 } else {
331 return entry;
332 }
333 }
334
335 rb_link_node(node, parent_node, p);
336 rb_insert_color_cached(node, root, leftmost);
337 return NULL;
338}
339
340static struct btrfs_delayed_ref_head *find_first_ref_head(
341 struct btrfs_delayed_ref_root *dr)
342{
343 struct rb_node *n;
344 struct btrfs_delayed_ref_head *entry;
345
346 n = rb_first_cached(&dr->href_root);
347 if (!n)
348 return NULL;
349
350 entry = rb_entry(n, struct btrfs_delayed_ref_head, href_node);
351
352 return entry;
353}
354
355/*
356 * Find a head entry based on bytenr. This returns the delayed ref head if it
357 * was able to find one, or NULL if nothing was in that spot. If return_bigger
358 * is given, the next bigger entry is returned if no exact match is found.
359 */
360static struct btrfs_delayed_ref_head *find_ref_head(
361 struct btrfs_delayed_ref_root *dr, u64 bytenr,
362 bool return_bigger)
363{
364 struct rb_root *root = &dr->href_root.rb_root;
365 struct rb_node *n;
366 struct btrfs_delayed_ref_head *entry;
367
368 n = root->rb_node;
369 entry = NULL;
370 while (n) {
371 entry = rb_entry(n, struct btrfs_delayed_ref_head, href_node);
372
373 if (bytenr < entry->bytenr)
374 n = n->rb_left;
375 else if (bytenr > entry->bytenr)
376 n = n->rb_right;
377 else
378 return entry;
379 }
380 if (entry && return_bigger) {
381 if (bytenr > entry->bytenr) {
382 n = rb_next(&entry->href_node);
383 if (!n)
384 return NULL;
385 entry = rb_entry(n, struct btrfs_delayed_ref_head,
386 href_node);
387 }
388 return entry;
389 }
390 return NULL;
391}
392
393int btrfs_delayed_ref_lock(struct btrfs_delayed_ref_root *delayed_refs,
394 struct btrfs_delayed_ref_head *head)
395{
396 lockdep_assert_held(&delayed_refs->lock);
397 if (mutex_trylock(&head->mutex))
398 return 0;
399
400 refcount_inc(&head->refs);
401 spin_unlock(&delayed_refs->lock);
402
403 mutex_lock(&head->mutex);
404 spin_lock(&delayed_refs->lock);
405 if (RB_EMPTY_NODE(&head->href_node)) {
406 mutex_unlock(&head->mutex);
407 btrfs_put_delayed_ref_head(head);
408 return -EAGAIN;
409 }
410 btrfs_put_delayed_ref_head(head);
411 return 0;
412}
413
414static inline void drop_delayed_ref(struct btrfs_trans_handle *trans,
415 struct btrfs_delayed_ref_root *delayed_refs,
416 struct btrfs_delayed_ref_head *head,
417 struct btrfs_delayed_ref_node *ref)
418{
419 lockdep_assert_held(&head->lock);
420 rb_erase_cached(&ref->ref_node, &head->ref_tree);
421 RB_CLEAR_NODE(&ref->ref_node);
422 if (!list_empty(&ref->add_list))
423 list_del(&ref->add_list);
424 ref->in_tree = 0;
425 btrfs_put_delayed_ref(ref);
426 atomic_dec(&delayed_refs->num_entries);
427}
428
429static bool merge_ref(struct btrfs_trans_handle *trans,
430 struct btrfs_delayed_ref_root *delayed_refs,
431 struct btrfs_delayed_ref_head *head,
432 struct btrfs_delayed_ref_node *ref,
433 u64 seq)
434{
435 struct btrfs_delayed_ref_node *next;
436 struct rb_node *node = rb_next(&ref->ref_node);
437 bool done = false;
438
439 while (!done && node) {
440 int mod;
441
442 next = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
443 node = rb_next(node);
444 if (seq && next->seq >= seq)
445 break;
446 if (comp_refs(ref, next, false))
447 break;
448
449 if (ref->action == next->action) {
450 mod = next->ref_mod;
451 } else {
452 if (ref->ref_mod < next->ref_mod) {
453 swap(ref, next);
454 done = true;
455 }
456 mod = -next->ref_mod;
457 }
458
459 drop_delayed_ref(trans, delayed_refs, head, next);
460 ref->ref_mod += mod;
461 if (ref->ref_mod == 0) {
462 drop_delayed_ref(trans, delayed_refs, head, ref);
463 done = true;
464 } else {
465 /*
466 * Can't have multiples of the same ref on a tree block.
467 */
468 WARN_ON(ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
469 ref->type == BTRFS_SHARED_BLOCK_REF_KEY);
470 }
471 }
472
473 return done;
474}
475
476void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
477 struct btrfs_delayed_ref_root *delayed_refs,
478 struct btrfs_delayed_ref_head *head)
479{
480 struct btrfs_fs_info *fs_info = trans->fs_info;
481 struct btrfs_delayed_ref_node *ref;
482 struct rb_node *node;
483 u64 seq = 0;
484
485 lockdep_assert_held(&head->lock);
486
487 if (RB_EMPTY_ROOT(&head->ref_tree.rb_root))
488 return;
489
490 /* We don't have too many refs to merge for data. */
491 if (head->is_data)
492 return;
493
494 read_lock(&fs_info->tree_mod_log_lock);
495 if (!list_empty(&fs_info->tree_mod_seq_list)) {
496 struct seq_list *elem;
497
498 elem = list_first_entry(&fs_info->tree_mod_seq_list,
499 struct seq_list, list);
500 seq = elem->seq;
501 }
502 read_unlock(&fs_info->tree_mod_log_lock);
503
504again:
505 for (node = rb_first_cached(&head->ref_tree); node;
506 node = rb_next(node)) {
507 ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
508 if (seq && ref->seq >= seq)
509 continue;
510 if (merge_ref(trans, delayed_refs, head, ref, seq))
511 goto again;
512 }
513}
514
515int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info, u64 seq)
516{
517 struct seq_list *elem;
518 int ret = 0;
519
520 read_lock(&fs_info->tree_mod_log_lock);
521 if (!list_empty(&fs_info->tree_mod_seq_list)) {
522 elem = list_first_entry(&fs_info->tree_mod_seq_list,
523 struct seq_list, list);
524 if (seq >= elem->seq) {
525 btrfs_debug(fs_info,
526 "holding back delayed_ref %#x.%x, lowest is %#x.%x",
527 (u32)(seq >> 32), (u32)seq,
528 (u32)(elem->seq >> 32), (u32)elem->seq);
529 ret = 1;
530 }
531 }
532
533 read_unlock(&fs_info->tree_mod_log_lock);
534 return ret;
535}
536
537struct btrfs_delayed_ref_head *btrfs_select_ref_head(
538 struct btrfs_delayed_ref_root *delayed_refs)
539{
540 struct btrfs_delayed_ref_head *head;
541
542again:
543 head = find_ref_head(delayed_refs, delayed_refs->run_delayed_start,
544 true);
545 if (!head && delayed_refs->run_delayed_start != 0) {
546 delayed_refs->run_delayed_start = 0;
547 head = find_first_ref_head(delayed_refs);
548 }
549 if (!head)
550 return NULL;
551
552 while (head->processing) {
553 struct rb_node *node;
554
555 node = rb_next(&head->href_node);
556 if (!node) {
557 if (delayed_refs->run_delayed_start == 0)
558 return NULL;
559 delayed_refs->run_delayed_start = 0;
560 goto again;
561 }
562 head = rb_entry(node, struct btrfs_delayed_ref_head,
563 href_node);
564 }
565
566 head->processing = 1;
567 WARN_ON(delayed_refs->num_heads_ready == 0);
568 delayed_refs->num_heads_ready--;
569 delayed_refs->run_delayed_start = head->bytenr +
570 head->num_bytes;
571 return head;
572}
573
574void btrfs_delete_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
575 struct btrfs_delayed_ref_head *head)
576{
577 lockdep_assert_held(&delayed_refs->lock);
578 lockdep_assert_held(&head->lock);
579
580 rb_erase_cached(&head->href_node, &delayed_refs->href_root);
581 RB_CLEAR_NODE(&head->href_node);
582 atomic_dec(&delayed_refs->num_entries);
583 delayed_refs->num_heads--;
584 if (head->processing == 0)
585 delayed_refs->num_heads_ready--;
586}
587
588/*
589 * Helper to insert the ref_node to the tail or merge with tail.
590 *
591 * Return 0 for insert.
592 * Return >0 for merge.
593 */
594static int insert_delayed_ref(struct btrfs_trans_handle *trans,
595 struct btrfs_delayed_ref_root *root,
596 struct btrfs_delayed_ref_head *href,
597 struct btrfs_delayed_ref_node *ref)
598{
599 struct btrfs_delayed_ref_node *exist;
600 int mod;
601 int ret = 0;
602
603 spin_lock(&href->lock);
604 exist = tree_insert(&href->ref_tree, ref);
605 if (!exist)
606 goto inserted;
607
608 /* Now we are sure we can merge */
609 ret = 1;
610 if (exist->action == ref->action) {
611 mod = ref->ref_mod;
612 } else {
613 /* Need to change action */
614 if (exist->ref_mod < ref->ref_mod) {
615 exist->action = ref->action;
616 mod = -exist->ref_mod;
617 exist->ref_mod = ref->ref_mod;
618 if (ref->action == BTRFS_ADD_DELAYED_REF)
619 list_add_tail(&exist->add_list,
620 &href->ref_add_list);
621 else if (ref->action == BTRFS_DROP_DELAYED_REF) {
622 ASSERT(!list_empty(&exist->add_list));
623 list_del(&exist->add_list);
624 } else {
625 ASSERT(0);
626 }
627 } else
628 mod = -ref->ref_mod;
629 }
630 exist->ref_mod += mod;
631
632 /* remove existing tail if its ref_mod is zero */
633 if (exist->ref_mod == 0)
634 drop_delayed_ref(trans, root, href, exist);
635 spin_unlock(&href->lock);
636 return ret;
637inserted:
638 if (ref->action == BTRFS_ADD_DELAYED_REF)
639 list_add_tail(&ref->add_list, &href->ref_add_list);
640 atomic_inc(&root->num_entries);
641 spin_unlock(&href->lock);
642 return ret;
643}
644
645/*
646 * helper function to update the accounting in the head ref
647 * existing and update must have the same bytenr
648 */
649static noinline void update_existing_head_ref(struct btrfs_trans_handle *trans,
650 struct btrfs_delayed_ref_head *existing,
651 struct btrfs_delayed_ref_head *update,
652 int *old_ref_mod_ret)
653{
654 struct btrfs_delayed_ref_root *delayed_refs =
655 &trans->transaction->delayed_refs;
656 struct btrfs_fs_info *fs_info = trans->fs_info;
657 int old_ref_mod;
658
659 BUG_ON(existing->is_data != update->is_data);
660
661 spin_lock(&existing->lock);
662 if (update->must_insert_reserved) {
663 /* if the extent was freed and then
664 * reallocated before the delayed ref
665 * entries were processed, we can end up
666 * with an existing head ref without
667 * the must_insert_reserved flag set.
668 * Set it again here
669 */
670 existing->must_insert_reserved = update->must_insert_reserved;
671
672 /*
673 * update the num_bytes so we make sure the accounting
674 * is done correctly
675 */
676 existing->num_bytes = update->num_bytes;
677
678 }
679
680 if (update->extent_op) {
681 if (!existing->extent_op) {
682 existing->extent_op = update->extent_op;
683 } else {
684 if (update->extent_op->update_key) {
685 memcpy(&existing->extent_op->key,
686 &update->extent_op->key,
687 sizeof(update->extent_op->key));
688 existing->extent_op->update_key = true;
689 }
690 if (update->extent_op->update_flags) {
691 existing->extent_op->flags_to_set |=
692 update->extent_op->flags_to_set;
693 existing->extent_op->update_flags = true;
694 }
695 btrfs_free_delayed_extent_op(update->extent_op);
696 }
697 }
698 /*
699 * update the reference mod on the head to reflect this new operation,
700 * only need the lock for this case cause we could be processing it
701 * currently, for refs we just added we know we're a-ok.
702 */
703 old_ref_mod = existing->total_ref_mod;
704 if (old_ref_mod_ret)
705 *old_ref_mod_ret = old_ref_mod;
706 existing->ref_mod += update->ref_mod;
707 existing->total_ref_mod += update->ref_mod;
708
709 /*
710 * If we are going to from a positive ref mod to a negative or vice
711 * versa we need to make sure to adjust pending_csums accordingly.
712 */
713 if (existing->is_data) {
714 u64 csum_leaves =
715 btrfs_csum_bytes_to_leaves(fs_info,
716 existing->num_bytes);
717
718 if (existing->total_ref_mod >= 0 && old_ref_mod < 0) {
719 delayed_refs->pending_csums -= existing->num_bytes;
720 btrfs_delayed_refs_rsv_release(fs_info, csum_leaves);
721 }
722 if (existing->total_ref_mod < 0 && old_ref_mod >= 0) {
723 delayed_refs->pending_csums += existing->num_bytes;
724 trans->delayed_ref_updates += csum_leaves;
725 }
726 }
727 spin_unlock(&existing->lock);
728}
729
730static void init_delayed_ref_head(struct btrfs_delayed_ref_head *head_ref,
731 struct btrfs_qgroup_extent_record *qrecord,
732 u64 bytenr, u64 num_bytes, u64 ref_root,
733 u64 reserved, int action, bool is_data,
734 bool is_system)
735{
736 int count_mod = 1;
737 int must_insert_reserved = 0;
738
739 /* If reserved is provided, it must be a data extent. */
740 BUG_ON(!is_data && reserved);
741
742 /*
743 * The head node stores the sum of all the mods, so dropping a ref
744 * should drop the sum in the head node by one.
745 */
746 if (action == BTRFS_UPDATE_DELAYED_HEAD)
747 count_mod = 0;
748 else if (action == BTRFS_DROP_DELAYED_REF)
749 count_mod = -1;
750
751 /*
752 * BTRFS_ADD_DELAYED_EXTENT means that we need to update the reserved
753 * accounting when the extent is finally added, or if a later
754 * modification deletes the delayed ref without ever inserting the
755 * extent into the extent allocation tree. ref->must_insert_reserved
756 * is the flag used to record that accounting mods are required.
757 *
758 * Once we record must_insert_reserved, switch the action to
759 * BTRFS_ADD_DELAYED_REF because other special casing is not required.
760 */
761 if (action == BTRFS_ADD_DELAYED_EXTENT)
762 must_insert_reserved = 1;
763 else
764 must_insert_reserved = 0;
765
766 refcount_set(&head_ref->refs, 1);
767 head_ref->bytenr = bytenr;
768 head_ref->num_bytes = num_bytes;
769 head_ref->ref_mod = count_mod;
770 head_ref->must_insert_reserved = must_insert_reserved;
771 head_ref->is_data = is_data;
772 head_ref->is_system = is_system;
773 head_ref->ref_tree = RB_ROOT_CACHED;
774 INIT_LIST_HEAD(&head_ref->ref_add_list);
775 RB_CLEAR_NODE(&head_ref->href_node);
776 head_ref->processing = 0;
777 head_ref->total_ref_mod = count_mod;
778 spin_lock_init(&head_ref->lock);
779 mutex_init(&head_ref->mutex);
780
781 if (qrecord) {
782 if (ref_root && reserved) {
783 qrecord->data_rsv = reserved;
784 qrecord->data_rsv_refroot = ref_root;
785 }
786 qrecord->bytenr = bytenr;
787 qrecord->num_bytes = num_bytes;
788 qrecord->old_roots = NULL;
789 }
790}
791
792/*
793 * helper function to actually insert a head node into the rbtree.
794 * this does all the dirty work in terms of maintaining the correct
795 * overall modification count.
796 */
797static noinline struct btrfs_delayed_ref_head *
798add_delayed_ref_head(struct btrfs_trans_handle *trans,
799 struct btrfs_delayed_ref_head *head_ref,
800 struct btrfs_qgroup_extent_record *qrecord,
801 int action, int *qrecord_inserted_ret,
802 int *old_ref_mod, int *new_ref_mod)
803{
804 struct btrfs_delayed_ref_head *existing;
805 struct btrfs_delayed_ref_root *delayed_refs;
806 int qrecord_inserted = 0;
807
808 delayed_refs = &trans->transaction->delayed_refs;
809
810 /* Record qgroup extent info if provided */
811 if (qrecord) {
812 if (btrfs_qgroup_trace_extent_nolock(trans->fs_info,
813 delayed_refs, qrecord))
814 kfree(qrecord);
815 else
816 qrecord_inserted = 1;
817 }
818
819 trace_add_delayed_ref_head(trans->fs_info, head_ref, action);
820
821 existing = htree_insert(&delayed_refs->href_root,
822 &head_ref->href_node);
823 if (existing) {
824 update_existing_head_ref(trans, existing, head_ref,
825 old_ref_mod);
826 /*
827 * we've updated the existing ref, free the newly
828 * allocated ref
829 */
830 kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
831 head_ref = existing;
832 } else {
833 if (old_ref_mod)
834 *old_ref_mod = 0;
835 if (head_ref->is_data && head_ref->ref_mod < 0) {
836 delayed_refs->pending_csums += head_ref->num_bytes;
837 trans->delayed_ref_updates +=
838 btrfs_csum_bytes_to_leaves(trans->fs_info,
839 head_ref->num_bytes);
840 }
841 delayed_refs->num_heads++;
842 delayed_refs->num_heads_ready++;
843 atomic_inc(&delayed_refs->num_entries);
844 trans->delayed_ref_updates++;
845 }
846 if (qrecord_inserted_ret)
847 *qrecord_inserted_ret = qrecord_inserted;
848 if (new_ref_mod)
849 *new_ref_mod = head_ref->total_ref_mod;
850
851 return head_ref;
852}
853
854/*
855 * init_delayed_ref_common - Initialize the structure which represents a
856 * modification to a an extent.
857 *
858 * @fs_info: Internal to the mounted filesystem mount structure.
859 *
860 * @ref: The structure which is going to be initialized.
861 *
862 * @bytenr: The logical address of the extent for which a modification is
863 * going to be recorded.
864 *
865 * @num_bytes: Size of the extent whose modification is being recorded.
866 *
867 * @ref_root: The id of the root where this modification has originated, this
868 * can be either one of the well-known metadata trees or the
869 * subvolume id which references this extent.
870 *
871 * @action: Can be one of BTRFS_ADD_DELAYED_REF/BTRFS_DROP_DELAYED_REF or
872 * BTRFS_ADD_DELAYED_EXTENT
873 *
874 * @ref_type: Holds the type of the extent which is being recorded, can be
875 * one of BTRFS_SHARED_BLOCK_REF_KEY/BTRFS_TREE_BLOCK_REF_KEY
876 * when recording a metadata extent or BTRFS_SHARED_DATA_REF_KEY/
877 * BTRFS_EXTENT_DATA_REF_KEY when recording data extent
878 */
879static void init_delayed_ref_common(struct btrfs_fs_info *fs_info,
880 struct btrfs_delayed_ref_node *ref,
881 u64 bytenr, u64 num_bytes, u64 ref_root,
882 int action, u8 ref_type)
883{
884 u64 seq = 0;
885
886 if (action == BTRFS_ADD_DELAYED_EXTENT)
887 action = BTRFS_ADD_DELAYED_REF;
888
889 if (is_fstree(ref_root))
890 seq = atomic64_read(&fs_info->tree_mod_seq);
891
892 refcount_set(&ref->refs, 1);
893 ref->bytenr = bytenr;
894 ref->num_bytes = num_bytes;
895 ref->ref_mod = 1;
896 ref->action = action;
897 ref->is_head = 0;
898 ref->in_tree = 1;
899 ref->seq = seq;
900 ref->type = ref_type;
901 RB_CLEAR_NODE(&ref->ref_node);
902 INIT_LIST_HEAD(&ref->add_list);
903}
904
905/*
906 * add a delayed tree ref. This does all of the accounting required
907 * to make sure the delayed ref is eventually processed before this
908 * transaction commits.
909 */
910int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans,
911 struct btrfs_ref *generic_ref,
912 struct btrfs_delayed_extent_op *extent_op,
913 int *old_ref_mod, int *new_ref_mod)
914{
915 struct btrfs_fs_info *fs_info = trans->fs_info;
916 struct btrfs_delayed_tree_ref *ref;
917 struct btrfs_delayed_ref_head *head_ref;
918 struct btrfs_delayed_ref_root *delayed_refs;
919 struct btrfs_qgroup_extent_record *record = NULL;
920 int qrecord_inserted;
921 bool is_system;
922 int action = generic_ref->action;
923 int level = generic_ref->tree_ref.level;
924 int ret;
925 u64 bytenr = generic_ref->bytenr;
926 u64 num_bytes = generic_ref->len;
927 u64 parent = generic_ref->parent;
928 u8 ref_type;
929
930 is_system = (generic_ref->real_root == BTRFS_CHUNK_TREE_OBJECTID);
931
932 ASSERT(generic_ref->type == BTRFS_REF_METADATA && generic_ref->action);
933 BUG_ON(extent_op && extent_op->is_data);
934 ref = kmem_cache_alloc(btrfs_delayed_tree_ref_cachep, GFP_NOFS);
935 if (!ref)
936 return -ENOMEM;
937
938 head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
939 if (!head_ref) {
940 kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
941 return -ENOMEM;
942 }
943
944 if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) &&
945 is_fstree(generic_ref->real_root) &&
946 is_fstree(generic_ref->tree_ref.root) &&
947 !generic_ref->skip_qgroup) {
948 record = kzalloc(sizeof(*record), GFP_NOFS);
949 if (!record) {
950 kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
951 kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
952 return -ENOMEM;
953 }
954 }
955
956 if (parent)
957 ref_type = BTRFS_SHARED_BLOCK_REF_KEY;
958 else
959 ref_type = BTRFS_TREE_BLOCK_REF_KEY;
960
961 init_delayed_ref_common(fs_info, &ref->node, bytenr, num_bytes,
962 generic_ref->tree_ref.root, action, ref_type);
963 ref->root = generic_ref->tree_ref.root;
964 ref->parent = parent;
965 ref->level = level;
966
967 init_delayed_ref_head(head_ref, record, bytenr, num_bytes,
968 generic_ref->tree_ref.root, 0, action, false,
969 is_system);
970 head_ref->extent_op = extent_op;
971
972 delayed_refs = &trans->transaction->delayed_refs;
973 spin_lock(&delayed_refs->lock);
974
975 /*
976 * insert both the head node and the new ref without dropping
977 * the spin lock
978 */
979 head_ref = add_delayed_ref_head(trans, head_ref, record,
980 action, &qrecord_inserted,
981 old_ref_mod, new_ref_mod);
982
983 ret = insert_delayed_ref(trans, delayed_refs, head_ref, &ref->node);
984 spin_unlock(&delayed_refs->lock);
985
986 /*
987 * Need to update the delayed_refs_rsv with any changes we may have
988 * made.
989 */
990 btrfs_update_delayed_refs_rsv(trans);
991
992 trace_add_delayed_tree_ref(fs_info, &ref->node, ref,
993 action == BTRFS_ADD_DELAYED_EXTENT ?
994 BTRFS_ADD_DELAYED_REF : action);
995 if (ret > 0)
996 kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
997
998 if (qrecord_inserted)
999 btrfs_qgroup_trace_extent_post(fs_info, record);
1000
1001 return 0;
1002}
1003
1004/*
1005 * add a delayed data ref. it's similar to btrfs_add_delayed_tree_ref.
1006 */
1007int btrfs_add_delayed_data_ref(struct btrfs_trans_handle *trans,
1008 struct btrfs_ref *generic_ref,
1009 u64 reserved, int *old_ref_mod,
1010 int *new_ref_mod)
1011{
1012 struct btrfs_fs_info *fs_info = trans->fs_info;
1013 struct btrfs_delayed_data_ref *ref;
1014 struct btrfs_delayed_ref_head *head_ref;
1015 struct btrfs_delayed_ref_root *delayed_refs;
1016 struct btrfs_qgroup_extent_record *record = NULL;
1017 int qrecord_inserted;
1018 int action = generic_ref->action;
1019 int ret;
1020 u64 bytenr = generic_ref->bytenr;
1021 u64 num_bytes = generic_ref->len;
1022 u64 parent = generic_ref->parent;
1023 u64 ref_root = generic_ref->data_ref.ref_root;
1024 u64 owner = generic_ref->data_ref.ino;
1025 u64 offset = generic_ref->data_ref.offset;
1026 u8 ref_type;
1027
1028 ASSERT(generic_ref->type == BTRFS_REF_DATA && action);
1029 ref = kmem_cache_alloc(btrfs_delayed_data_ref_cachep, GFP_NOFS);
1030 if (!ref)
1031 return -ENOMEM;
1032
1033 if (parent)
1034 ref_type = BTRFS_SHARED_DATA_REF_KEY;
1035 else
1036 ref_type = BTRFS_EXTENT_DATA_REF_KEY;
1037 init_delayed_ref_common(fs_info, &ref->node, bytenr, num_bytes,
1038 ref_root, action, ref_type);
1039 ref->root = ref_root;
1040 ref->parent = parent;
1041 ref->objectid = owner;
1042 ref->offset = offset;
1043
1044
1045 head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
1046 if (!head_ref) {
1047 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
1048 return -ENOMEM;
1049 }
1050
1051 if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) &&
1052 is_fstree(ref_root) &&
1053 is_fstree(generic_ref->real_root) &&
1054 !generic_ref->skip_qgroup) {
1055 record = kzalloc(sizeof(*record), GFP_NOFS);
1056 if (!record) {
1057 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
1058 kmem_cache_free(btrfs_delayed_ref_head_cachep,
1059 head_ref);
1060 return -ENOMEM;
1061 }
1062 }
1063
1064 init_delayed_ref_head(head_ref, record, bytenr, num_bytes, ref_root,
1065 reserved, action, true, false);
1066 head_ref->extent_op = NULL;
1067
1068 delayed_refs = &trans->transaction->delayed_refs;
1069 spin_lock(&delayed_refs->lock);
1070
1071 /*
1072 * insert both the head node and the new ref without dropping
1073 * the spin lock
1074 */
1075 head_ref = add_delayed_ref_head(trans, head_ref, record,
1076 action, &qrecord_inserted,
1077 old_ref_mod, new_ref_mod);
1078
1079 ret = insert_delayed_ref(trans, delayed_refs, head_ref, &ref->node);
1080 spin_unlock(&delayed_refs->lock);
1081
1082 /*
1083 * Need to update the delayed_refs_rsv with any changes we may have
1084 * made.
1085 */
1086 btrfs_update_delayed_refs_rsv(trans);
1087
1088 trace_add_delayed_data_ref(trans->fs_info, &ref->node, ref,
1089 action == BTRFS_ADD_DELAYED_EXTENT ?
1090 BTRFS_ADD_DELAYED_REF : action);
1091 if (ret > 0)
1092 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
1093
1094
1095 if (qrecord_inserted)
1096 return btrfs_qgroup_trace_extent_post(fs_info, record);
1097 return 0;
1098}
1099
1100int btrfs_add_delayed_extent_op(struct btrfs_trans_handle *trans,
1101 u64 bytenr, u64 num_bytes,
1102 struct btrfs_delayed_extent_op *extent_op)
1103{
1104 struct btrfs_delayed_ref_head *head_ref;
1105 struct btrfs_delayed_ref_root *delayed_refs;
1106
1107 head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
1108 if (!head_ref)
1109 return -ENOMEM;
1110
1111 init_delayed_ref_head(head_ref, NULL, bytenr, num_bytes, 0, 0,
1112 BTRFS_UPDATE_DELAYED_HEAD, extent_op->is_data,
1113 false);
1114 head_ref->extent_op = extent_op;
1115
1116 delayed_refs = &trans->transaction->delayed_refs;
1117 spin_lock(&delayed_refs->lock);
1118
1119 add_delayed_ref_head(trans, head_ref, NULL, BTRFS_UPDATE_DELAYED_HEAD,
1120 NULL, NULL, NULL);
1121
1122 spin_unlock(&delayed_refs->lock);
1123
1124 /*
1125 * Need to update the delayed_refs_rsv with any changes we may have
1126 * made.
1127 */
1128 btrfs_update_delayed_refs_rsv(trans);
1129 return 0;
1130}
1131
1132/*
1133 * This does a simple search for the head node for a given extent. Returns the
1134 * head node if found, or NULL if not.
1135 */
1136struct btrfs_delayed_ref_head *
1137btrfs_find_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs, u64 bytenr)
1138{
1139 lockdep_assert_held(&delayed_refs->lock);
1140
1141 return find_ref_head(delayed_refs, bytenr, false);
1142}
1143
1144void __cold btrfs_delayed_ref_exit(void)
1145{
1146 kmem_cache_destroy(btrfs_delayed_ref_head_cachep);
1147 kmem_cache_destroy(btrfs_delayed_tree_ref_cachep);
1148 kmem_cache_destroy(btrfs_delayed_data_ref_cachep);
1149 kmem_cache_destroy(btrfs_delayed_extent_op_cachep);
1150}
1151
1152int __init btrfs_delayed_ref_init(void)
1153{
1154 btrfs_delayed_ref_head_cachep = kmem_cache_create(
1155 "btrfs_delayed_ref_head",
1156 sizeof(struct btrfs_delayed_ref_head), 0,
1157 SLAB_MEM_SPREAD, NULL);
1158 if (!btrfs_delayed_ref_head_cachep)
1159 goto fail;
1160
1161 btrfs_delayed_tree_ref_cachep = kmem_cache_create(
1162 "btrfs_delayed_tree_ref",
1163 sizeof(struct btrfs_delayed_tree_ref), 0,
1164 SLAB_MEM_SPREAD, NULL);
1165 if (!btrfs_delayed_tree_ref_cachep)
1166 goto fail;
1167
1168 btrfs_delayed_data_ref_cachep = kmem_cache_create(
1169 "btrfs_delayed_data_ref",
1170 sizeof(struct btrfs_delayed_data_ref), 0,
1171 SLAB_MEM_SPREAD, NULL);
1172 if (!btrfs_delayed_data_ref_cachep)
1173 goto fail;
1174
1175 btrfs_delayed_extent_op_cachep = kmem_cache_create(
1176 "btrfs_delayed_extent_op",
1177 sizeof(struct btrfs_delayed_extent_op), 0,
1178 SLAB_MEM_SPREAD, NULL);
1179 if (!btrfs_delayed_extent_op_cachep)
1180 goto fail;
1181
1182 return 0;
1183fail:
1184 btrfs_delayed_ref_exit();
1185 return -ENOMEM;
1186}