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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/*
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
26struct kmem_cache *btrfs_delayed_ref_head_cachep;
27struct kmem_cache *btrfs_delayed_tree_ref_cachep;
28struct kmem_cache *btrfs_delayed_data_ref_cachep;
29struct kmem_cache *btrfs_delayed_extent_op_cachep;
30/*
31 * delayed back reference update tracking. For subvolume trees
32 * we queue up extent allocations and backref maintenance for
33 * delayed processing. This avoids deep call chains where we
34 * add extents in the middle of btrfs_search_slot, and it allows
35 * us to buffer up frequently modified backrefs in an rb tree instead
36 * of hammering updates on the extent allocation tree.
37 */
38
39/*
40 * compare two delayed tree backrefs with same bytenr and type
41 */
42static int comp_tree_refs(struct btrfs_delayed_tree_ref *ref2,
43 struct btrfs_delayed_tree_ref *ref1, int type)
44{
45 if (type == BTRFS_TREE_BLOCK_REF_KEY) {
46 if (ref1->root < ref2->root)
47 return -1;
48 if (ref1->root > ref2->root)
49 return 1;
50 } else {
51 if (ref1->parent < ref2->parent)
52 return -1;
53 if (ref1->parent > ref2->parent)
54 return 1;
55 }
56 return 0;
57}
58
59/*
60 * compare two delayed data backrefs with same bytenr and type
61 */
62static int comp_data_refs(struct btrfs_delayed_data_ref *ref2,
63 struct btrfs_delayed_data_ref *ref1)
64{
65 if (ref1->node.type == BTRFS_EXTENT_DATA_REF_KEY) {
66 if (ref1->root < ref2->root)
67 return -1;
68 if (ref1->root > ref2->root)
69 return 1;
70 if (ref1->objectid < ref2->objectid)
71 return -1;
72 if (ref1->objectid > ref2->objectid)
73 return 1;
74 if (ref1->offset < ref2->offset)
75 return -1;
76 if (ref1->offset > ref2->offset)
77 return 1;
78 } else {
79 if (ref1->parent < ref2->parent)
80 return -1;
81 if (ref1->parent > ref2->parent)
82 return 1;
83 }
84 return 0;
85}
86
87/*
88 * entries in the rb tree are ordered by the byte number of the extent,
89 * type of the delayed backrefs and content of delayed backrefs.
90 */
91static int comp_entry(struct btrfs_delayed_ref_node *ref2,
92 struct btrfs_delayed_ref_node *ref1,
93 bool compare_seq)
94{
95 if (ref1->bytenr < ref2->bytenr)
96 return -1;
97 if (ref1->bytenr > ref2->bytenr)
98 return 1;
99 if (ref1->is_head && ref2->is_head)
100 return 0;
101 if (ref2->is_head)
102 return -1;
103 if (ref1->is_head)
104 return 1;
105 if (ref1->type < ref2->type)
106 return -1;
107 if (ref1->type > ref2->type)
108 return 1;
109 /* merging of sequenced refs is not allowed */
110 if (compare_seq) {
111 if (ref1->seq < ref2->seq)
112 return -1;
113 if (ref1->seq > ref2->seq)
114 return 1;
115 }
116 if (ref1->type == BTRFS_TREE_BLOCK_REF_KEY ||
117 ref1->type == BTRFS_SHARED_BLOCK_REF_KEY) {
118 return comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref2),
119 btrfs_delayed_node_to_tree_ref(ref1),
120 ref1->type);
121 } else if (ref1->type == BTRFS_EXTENT_DATA_REF_KEY ||
122 ref1->type == BTRFS_SHARED_DATA_REF_KEY) {
123 return comp_data_refs(btrfs_delayed_node_to_data_ref(ref2),
124 btrfs_delayed_node_to_data_ref(ref1));
125 }
126 BUG();
127 return 0;
128}
129
130/*
131 * insert a new ref into the rbtree. This returns any existing refs
132 * for the same (bytenr,parent) tuple, or NULL if the new node was properly
133 * inserted.
134 */
135static struct btrfs_delayed_ref_node *tree_insert(struct rb_root *root,
136 struct rb_node *node)
137{
138 struct rb_node **p = &root->rb_node;
139 struct rb_node *parent_node = NULL;
140 struct btrfs_delayed_ref_node *entry;
141 struct btrfs_delayed_ref_node *ins;
142 int cmp;
143
144 ins = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
145 while (*p) {
146 parent_node = *p;
147 entry = rb_entry(parent_node, struct btrfs_delayed_ref_node,
148 rb_node);
149
150 cmp = comp_entry(entry, ins, 1);
151 if (cmp < 0)
152 p = &(*p)->rb_left;
153 else if (cmp > 0)
154 p = &(*p)->rb_right;
155 else
156 return entry;
157 }
158
159 rb_link_node(node, parent_node, p);
160 rb_insert_color(node, root);
161 return NULL;
162}
163
164/* insert a new ref to head ref rbtree */
165static struct btrfs_delayed_ref_head *htree_insert(struct rb_root *root,
166 struct rb_node *node)
167{
168 struct rb_node **p = &root->rb_node;
169 struct rb_node *parent_node = NULL;
170 struct btrfs_delayed_ref_head *entry;
171 struct btrfs_delayed_ref_head *ins;
172 u64 bytenr;
173
174 ins = rb_entry(node, struct btrfs_delayed_ref_head, href_node);
175 bytenr = ins->node.bytenr;
176 while (*p) {
177 parent_node = *p;
178 entry = rb_entry(parent_node, struct btrfs_delayed_ref_head,
179 href_node);
180
181 if (bytenr < entry->node.bytenr)
182 p = &(*p)->rb_left;
183 else if (bytenr > entry->node.bytenr)
184 p = &(*p)->rb_right;
185 else
186 return entry;
187 }
188
189 rb_link_node(node, parent_node, p);
190 rb_insert_color(node, root);
191 return NULL;
192}
193
194/*
195 * find an head entry based on bytenr. This returns the delayed ref
196 * head if it was able to find one, or NULL if nothing was in that spot.
197 * If return_bigger is given, the next bigger entry is returned if no exact
198 * match is found.
199 */
200static struct btrfs_delayed_ref_head *
201find_ref_head(struct rb_root *root, u64 bytenr,
202 int return_bigger)
203{
204 struct rb_node *n;
205 struct btrfs_delayed_ref_head *entry;
206
207 n = root->rb_node;
208 entry = NULL;
209 while (n) {
210 entry = rb_entry(n, struct btrfs_delayed_ref_head, href_node);
211
212 if (bytenr < entry->node.bytenr)
213 n = n->rb_left;
214 else if (bytenr > entry->node.bytenr)
215 n = n->rb_right;
216 else
217 return entry;
218 }
219 if (entry && return_bigger) {
220 if (bytenr > entry->node.bytenr) {
221 n = rb_next(&entry->href_node);
222 if (!n)
223 n = rb_first(root);
224 entry = rb_entry(n, struct btrfs_delayed_ref_head,
225 href_node);
226 return entry;
227 }
228 return entry;
229 }
230 return NULL;
231}
232
233int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
234 struct btrfs_delayed_ref_head *head)
235{
236 struct btrfs_delayed_ref_root *delayed_refs;
237
238 delayed_refs = &trans->transaction->delayed_refs;
239 assert_spin_locked(&delayed_refs->lock);
240 if (mutex_trylock(&head->mutex))
241 return 0;
242
243 atomic_inc(&head->node.refs);
244 spin_unlock(&delayed_refs->lock);
245
246 mutex_lock(&head->mutex);
247 spin_lock(&delayed_refs->lock);
248 if (!head->node.in_tree) {
249 mutex_unlock(&head->mutex);
250 btrfs_put_delayed_ref(&head->node);
251 return -EAGAIN;
252 }
253 btrfs_put_delayed_ref(&head->node);
254 return 0;
255}
256
257static inline void drop_delayed_ref(struct btrfs_trans_handle *trans,
258 struct btrfs_delayed_ref_root *delayed_refs,
259 struct btrfs_delayed_ref_head *head,
260 struct btrfs_delayed_ref_node *ref)
261{
262 if (btrfs_delayed_ref_is_head(ref)) {
263 head = btrfs_delayed_node_to_head(ref);
264 rb_erase(&head->href_node, &delayed_refs->href_root);
265 } else {
266 assert_spin_locked(&head->lock);
267 rb_erase(&ref->rb_node, &head->ref_root);
268 }
269 ref->in_tree = 0;
270 btrfs_put_delayed_ref(ref);
271 atomic_dec(&delayed_refs->num_entries);
272 if (trans->delayed_ref_updates)
273 trans->delayed_ref_updates--;
274}
275
276static int merge_ref(struct btrfs_trans_handle *trans,
277 struct btrfs_delayed_ref_root *delayed_refs,
278 struct btrfs_delayed_ref_head *head,
279 struct btrfs_delayed_ref_node *ref, u64 seq)
280{
281 struct rb_node *node;
282 int mod = 0;
283 int done = 0;
284
285 node = rb_next(&ref->rb_node);
286 while (!done && node) {
287 struct btrfs_delayed_ref_node *next;
288
289 next = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
290 node = rb_next(node);
291 if (seq && next->seq >= seq)
292 break;
293 if (comp_entry(ref, next, 0))
294 continue;
295
296 if (ref->action == next->action) {
297 mod = next->ref_mod;
298 } else {
299 if (ref->ref_mod < next->ref_mod) {
300 struct btrfs_delayed_ref_node *tmp;
301
302 tmp = ref;
303 ref = next;
304 next = tmp;
305 done = 1;
306 }
307 mod = -next->ref_mod;
308 }
309
310 drop_delayed_ref(trans, delayed_refs, head, next);
311 ref->ref_mod += mod;
312 if (ref->ref_mod == 0) {
313 drop_delayed_ref(trans, delayed_refs, head, ref);
314 done = 1;
315 } else {
316 /*
317 * You can't have multiples of the same ref on a tree
318 * block.
319 */
320 WARN_ON(ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
321 ref->type == BTRFS_SHARED_BLOCK_REF_KEY);
322 }
323 }
324 return done;
325}
326
327void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
328 struct btrfs_fs_info *fs_info,
329 struct btrfs_delayed_ref_root *delayed_refs,
330 struct btrfs_delayed_ref_head *head)
331{
332 struct rb_node *node;
333 u64 seq = 0;
334
335 assert_spin_locked(&head->lock);
336 /*
337 * We don't have too much refs to merge in the case of delayed data
338 * refs.
339 */
340 if (head->is_data)
341 return;
342
343 spin_lock(&fs_info->tree_mod_seq_lock);
344 if (!list_empty(&fs_info->tree_mod_seq_list)) {
345 struct seq_list *elem;
346
347 elem = list_first_entry(&fs_info->tree_mod_seq_list,
348 struct seq_list, list);
349 seq = elem->seq;
350 }
351 spin_unlock(&fs_info->tree_mod_seq_lock);
352
353 node = rb_first(&head->ref_root);
354 while (node) {
355 struct btrfs_delayed_ref_node *ref;
356
357 ref = rb_entry(node, struct btrfs_delayed_ref_node,
358 rb_node);
359 /* We can't merge refs that are outside of our seq count */
360 if (seq && ref->seq >= seq)
361 break;
362 if (merge_ref(trans, delayed_refs, head, ref, seq))
363 node = rb_first(&head->ref_root);
364 else
365 node = rb_next(&ref->rb_node);
366 }
367}
368
369int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
370 struct btrfs_delayed_ref_root *delayed_refs,
371 u64 seq)
372{
373 struct seq_list *elem;
374 int ret = 0;
375
376 spin_lock(&fs_info->tree_mod_seq_lock);
377 if (!list_empty(&fs_info->tree_mod_seq_list)) {
378 elem = list_first_entry(&fs_info->tree_mod_seq_list,
379 struct seq_list, list);
380 if (seq >= elem->seq) {
381 pr_debug("holding back delayed_ref %#x.%x, lowest is %#x.%x (%p)\n",
382 (u32)(seq >> 32), (u32)seq,
383 (u32)(elem->seq >> 32), (u32)elem->seq,
384 delayed_refs);
385 ret = 1;
386 }
387 }
388
389 spin_unlock(&fs_info->tree_mod_seq_lock);
390 return ret;
391}
392
393struct btrfs_delayed_ref_head *
394btrfs_select_ref_head(struct btrfs_trans_handle *trans)
395{
396 struct btrfs_delayed_ref_root *delayed_refs;
397 struct btrfs_delayed_ref_head *head;
398 u64 start;
399 bool loop = false;
400
401 delayed_refs = &trans->transaction->delayed_refs;
402
403again:
404 start = delayed_refs->run_delayed_start;
405 head = find_ref_head(&delayed_refs->href_root, start, 1);
406 if (!head && !loop) {
407 delayed_refs->run_delayed_start = 0;
408 start = 0;
409 loop = true;
410 head = find_ref_head(&delayed_refs->href_root, start, 1);
411 if (!head)
412 return NULL;
413 } else if (!head && loop) {
414 return NULL;
415 }
416
417 while (head->processing) {
418 struct rb_node *node;
419
420 node = rb_next(&head->href_node);
421 if (!node) {
422 if (loop)
423 return NULL;
424 delayed_refs->run_delayed_start = 0;
425 start = 0;
426 loop = true;
427 goto again;
428 }
429 head = rb_entry(node, struct btrfs_delayed_ref_head,
430 href_node);
431 }
432
433 head->processing = 1;
434 WARN_ON(delayed_refs->num_heads_ready == 0);
435 delayed_refs->num_heads_ready--;
436 delayed_refs->run_delayed_start = head->node.bytenr +
437 head->node.num_bytes;
438 return head;
439}
440
441/*
442 * helper function to update an extent delayed ref in the
443 * rbtree. existing and update must both have the same
444 * bytenr and parent
445 *
446 * This may free existing if the update cancels out whatever
447 * operation it was doing.
448 */
449static noinline void
450update_existing_ref(struct btrfs_trans_handle *trans,
451 struct btrfs_delayed_ref_root *delayed_refs,
452 struct btrfs_delayed_ref_head *head,
453 struct btrfs_delayed_ref_node *existing,
454 struct btrfs_delayed_ref_node *update)
455{
456 if (update->action != existing->action) {
457 /*
458 * this is effectively undoing either an add or a
459 * drop. We decrement the ref_mod, and if it goes
460 * down to zero we just delete the entry without
461 * every changing the extent allocation tree.
462 */
463 existing->ref_mod--;
464 if (existing->ref_mod == 0)
465 drop_delayed_ref(trans, delayed_refs, head, existing);
466 else
467 WARN_ON(existing->type == BTRFS_TREE_BLOCK_REF_KEY ||
468 existing->type == BTRFS_SHARED_BLOCK_REF_KEY);
469 } else {
470 WARN_ON(existing->type == BTRFS_TREE_BLOCK_REF_KEY ||
471 existing->type == BTRFS_SHARED_BLOCK_REF_KEY);
472 /*
473 * the action on the existing ref matches
474 * the action on the ref we're trying to add.
475 * Bump the ref_mod by one so the backref that
476 * is eventually added/removed has the correct
477 * reference count
478 */
479 existing->ref_mod += update->ref_mod;
480 }
481}
482
483/*
484 * helper function to update the accounting in the head ref
485 * existing and update must have the same bytenr
486 */
487static noinline void
488update_existing_head_ref(struct btrfs_delayed_ref_node *existing,
489 struct btrfs_delayed_ref_node *update)
490{
491 struct btrfs_delayed_ref_head *existing_ref;
492 struct btrfs_delayed_ref_head *ref;
493
494 existing_ref = btrfs_delayed_node_to_head(existing);
495 ref = btrfs_delayed_node_to_head(update);
496 BUG_ON(existing_ref->is_data != ref->is_data);
497
498 spin_lock(&existing_ref->lock);
499 if (ref->must_insert_reserved) {
500 /* if the extent was freed and then
501 * reallocated before the delayed ref
502 * entries were processed, we can end up
503 * with an existing head ref without
504 * the must_insert_reserved flag set.
505 * Set it again here
506 */
507 existing_ref->must_insert_reserved = ref->must_insert_reserved;
508
509 /*
510 * update the num_bytes so we make sure the accounting
511 * is done correctly
512 */
513 existing->num_bytes = update->num_bytes;
514
515 }
516
517 if (ref->extent_op) {
518 if (!existing_ref->extent_op) {
519 existing_ref->extent_op = ref->extent_op;
520 } else {
521 if (ref->extent_op->update_key) {
522 memcpy(&existing_ref->extent_op->key,
523 &ref->extent_op->key,
524 sizeof(ref->extent_op->key));
525 existing_ref->extent_op->update_key = 1;
526 }
527 if (ref->extent_op->update_flags) {
528 existing_ref->extent_op->flags_to_set |=
529 ref->extent_op->flags_to_set;
530 existing_ref->extent_op->update_flags = 1;
531 }
532 btrfs_free_delayed_extent_op(ref->extent_op);
533 }
534 }
535 /*
536 * update the reference mod on the head to reflect this new operation,
537 * only need the lock for this case cause we could be processing it
538 * currently, for refs we just added we know we're a-ok.
539 */
540 existing->ref_mod += update->ref_mod;
541 spin_unlock(&existing_ref->lock);
542}
543
544/*
545 * helper function to actually insert a head node into the rbtree.
546 * this does all the dirty work in terms of maintaining the correct
547 * overall modification count.
548 */
549static noinline struct btrfs_delayed_ref_head *
550add_delayed_ref_head(struct btrfs_fs_info *fs_info,
551 struct btrfs_trans_handle *trans,
552 struct btrfs_delayed_ref_node *ref, u64 bytenr,
553 u64 num_bytes, int action, int is_data)
554{
555 struct btrfs_delayed_ref_head *existing;
556 struct btrfs_delayed_ref_head *head_ref = NULL;
557 struct btrfs_delayed_ref_root *delayed_refs;
558 int count_mod = 1;
559 int must_insert_reserved = 0;
560
561 /*
562 * the head node stores the sum of all the mods, so dropping a ref
563 * should drop the sum in the head node by one.
564 */
565 if (action == BTRFS_UPDATE_DELAYED_HEAD)
566 count_mod = 0;
567 else if (action == BTRFS_DROP_DELAYED_REF)
568 count_mod = -1;
569
570 /*
571 * BTRFS_ADD_DELAYED_EXTENT means that we need to update
572 * the reserved accounting when the extent is finally added, or
573 * if a later modification deletes the delayed ref without ever
574 * inserting the extent into the extent allocation tree.
575 * ref->must_insert_reserved is the flag used to record
576 * that accounting mods are required.
577 *
578 * Once we record must_insert_reserved, switch the action to
579 * BTRFS_ADD_DELAYED_REF because other special casing is not required.
580 */
581 if (action == BTRFS_ADD_DELAYED_EXTENT)
582 must_insert_reserved = 1;
583 else
584 must_insert_reserved = 0;
585
586 delayed_refs = &trans->transaction->delayed_refs;
587
588 /* first set the basic ref node struct up */
589 atomic_set(&ref->refs, 1);
590 ref->bytenr = bytenr;
591 ref->num_bytes = num_bytes;
592 ref->ref_mod = count_mod;
593 ref->type = 0;
594 ref->action = 0;
595 ref->is_head = 1;
596 ref->in_tree = 1;
597 ref->seq = 0;
598
599 head_ref = btrfs_delayed_node_to_head(ref);
600 head_ref->must_insert_reserved = must_insert_reserved;
601 head_ref->is_data = is_data;
602 head_ref->ref_root = RB_ROOT;
603 head_ref->processing = 0;
604
605 spin_lock_init(&head_ref->lock);
606 mutex_init(&head_ref->mutex);
607
608 trace_add_delayed_ref_head(ref, head_ref, action);
609
610 existing = htree_insert(&delayed_refs->href_root,
611 &head_ref->href_node);
612 if (existing) {
613 update_existing_head_ref(&existing->node, ref);
614 /*
615 * we've updated the existing ref, free the newly
616 * allocated ref
617 */
618 kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
619 head_ref = existing;
620 } else {
621 delayed_refs->num_heads++;
622 delayed_refs->num_heads_ready++;
623 atomic_inc(&delayed_refs->num_entries);
624 trans->delayed_ref_updates++;
625 }
626 return head_ref;
627}
628
629/*
630 * helper to insert a delayed tree ref into the rbtree.
631 */
632static noinline void
633add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
634 struct btrfs_trans_handle *trans,
635 struct btrfs_delayed_ref_head *head_ref,
636 struct btrfs_delayed_ref_node *ref, u64 bytenr,
637 u64 num_bytes, u64 parent, u64 ref_root, int level,
638 int action, int for_cow)
639{
640 struct btrfs_delayed_ref_node *existing;
641 struct btrfs_delayed_tree_ref *full_ref;
642 struct btrfs_delayed_ref_root *delayed_refs;
643 u64 seq = 0;
644
645 if (action == BTRFS_ADD_DELAYED_EXTENT)
646 action = BTRFS_ADD_DELAYED_REF;
647
648 delayed_refs = &trans->transaction->delayed_refs;
649
650 /* first set the basic ref node struct up */
651 atomic_set(&ref->refs, 1);
652 ref->bytenr = bytenr;
653 ref->num_bytes = num_bytes;
654 ref->ref_mod = 1;
655 ref->action = action;
656 ref->is_head = 0;
657 ref->in_tree = 1;
658
659 if (need_ref_seq(for_cow, ref_root))
660 seq = btrfs_get_tree_mod_seq(fs_info, &trans->delayed_ref_elem);
661 ref->seq = seq;
662
663 full_ref = btrfs_delayed_node_to_tree_ref(ref);
664 full_ref->parent = parent;
665 full_ref->root = ref_root;
666 if (parent)
667 ref->type = BTRFS_SHARED_BLOCK_REF_KEY;
668 else
669 ref->type = BTRFS_TREE_BLOCK_REF_KEY;
670 full_ref->level = level;
671
672 trace_add_delayed_tree_ref(ref, full_ref, action);
673
674 spin_lock(&head_ref->lock);
675 existing = tree_insert(&head_ref->ref_root, &ref->rb_node);
676 if (existing) {
677 update_existing_ref(trans, delayed_refs, head_ref, existing,
678 ref);
679 /*
680 * we've updated the existing ref, free the newly
681 * allocated ref
682 */
683 kmem_cache_free(btrfs_delayed_tree_ref_cachep, full_ref);
684 } else {
685 atomic_inc(&delayed_refs->num_entries);
686 trans->delayed_ref_updates++;
687 }
688 spin_unlock(&head_ref->lock);
689}
690
691/*
692 * helper to insert a delayed data ref into the rbtree.
693 */
694static noinline void
695add_delayed_data_ref(struct btrfs_fs_info *fs_info,
696 struct btrfs_trans_handle *trans,
697 struct btrfs_delayed_ref_head *head_ref,
698 struct btrfs_delayed_ref_node *ref, u64 bytenr,
699 u64 num_bytes, u64 parent, u64 ref_root, u64 owner,
700 u64 offset, int action, int for_cow)
701{
702 struct btrfs_delayed_ref_node *existing;
703 struct btrfs_delayed_data_ref *full_ref;
704 struct btrfs_delayed_ref_root *delayed_refs;
705 u64 seq = 0;
706
707 if (action == BTRFS_ADD_DELAYED_EXTENT)
708 action = BTRFS_ADD_DELAYED_REF;
709
710 delayed_refs = &trans->transaction->delayed_refs;
711
712 /* first set the basic ref node struct up */
713 atomic_set(&ref->refs, 1);
714 ref->bytenr = bytenr;
715 ref->num_bytes = num_bytes;
716 ref->ref_mod = 1;
717 ref->action = action;
718 ref->is_head = 0;
719 ref->in_tree = 1;
720
721 if (need_ref_seq(for_cow, ref_root))
722 seq = btrfs_get_tree_mod_seq(fs_info, &trans->delayed_ref_elem);
723 ref->seq = seq;
724
725 full_ref = btrfs_delayed_node_to_data_ref(ref);
726 full_ref->parent = parent;
727 full_ref->root = ref_root;
728 if (parent)
729 ref->type = BTRFS_SHARED_DATA_REF_KEY;
730 else
731 ref->type = BTRFS_EXTENT_DATA_REF_KEY;
732
733 full_ref->objectid = owner;
734 full_ref->offset = offset;
735
736 trace_add_delayed_data_ref(ref, full_ref, action);
737
738 spin_lock(&head_ref->lock);
739 existing = tree_insert(&head_ref->ref_root, &ref->rb_node);
740 if (existing) {
741 update_existing_ref(trans, delayed_refs, head_ref, existing,
742 ref);
743 /*
744 * we've updated the existing ref, free the newly
745 * allocated ref
746 */
747 kmem_cache_free(btrfs_delayed_data_ref_cachep, full_ref);
748 } else {
749 atomic_inc(&delayed_refs->num_entries);
750 trans->delayed_ref_updates++;
751 }
752 spin_unlock(&head_ref->lock);
753}
754
755/*
756 * add a delayed tree ref. This does all of the accounting required
757 * to make sure the delayed ref is eventually processed before this
758 * transaction commits.
759 */
760int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
761 struct btrfs_trans_handle *trans,
762 u64 bytenr, u64 num_bytes, u64 parent,
763 u64 ref_root, int level, int action,
764 struct btrfs_delayed_extent_op *extent_op,
765 int for_cow)
766{
767 struct btrfs_delayed_tree_ref *ref;
768 struct btrfs_delayed_ref_head *head_ref;
769 struct btrfs_delayed_ref_root *delayed_refs;
770
771 BUG_ON(extent_op && extent_op->is_data);
772 ref = kmem_cache_alloc(btrfs_delayed_tree_ref_cachep, GFP_NOFS);
773 if (!ref)
774 return -ENOMEM;
775
776 head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
777 if (!head_ref) {
778 kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
779 return -ENOMEM;
780 }
781
782 head_ref->extent_op = extent_op;
783
784 delayed_refs = &trans->transaction->delayed_refs;
785 spin_lock(&delayed_refs->lock);
786
787 /*
788 * insert both the head node and the new ref without dropping
789 * the spin lock
790 */
791 head_ref = add_delayed_ref_head(fs_info, trans, &head_ref->node,
792 bytenr, num_bytes, action, 0);
793
794 add_delayed_tree_ref(fs_info, trans, head_ref, &ref->node, bytenr,
795 num_bytes, parent, ref_root, level, action,
796 for_cow);
797 spin_unlock(&delayed_refs->lock);
798 if (need_ref_seq(for_cow, ref_root))
799 btrfs_qgroup_record_ref(trans, &ref->node, extent_op);
800
801 return 0;
802}
803
804/*
805 * add a delayed data ref. it's similar to btrfs_add_delayed_tree_ref.
806 */
807int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
808 struct btrfs_trans_handle *trans,
809 u64 bytenr, u64 num_bytes,
810 u64 parent, u64 ref_root,
811 u64 owner, u64 offset, int action,
812 struct btrfs_delayed_extent_op *extent_op,
813 int for_cow)
814{
815 struct btrfs_delayed_data_ref *ref;
816 struct btrfs_delayed_ref_head *head_ref;
817 struct btrfs_delayed_ref_root *delayed_refs;
818
819 BUG_ON(extent_op && !extent_op->is_data);
820 ref = kmem_cache_alloc(btrfs_delayed_data_ref_cachep, GFP_NOFS);
821 if (!ref)
822 return -ENOMEM;
823
824 head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
825 if (!head_ref) {
826 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
827 return -ENOMEM;
828 }
829
830 head_ref->extent_op = extent_op;
831
832 delayed_refs = &trans->transaction->delayed_refs;
833 spin_lock(&delayed_refs->lock);
834
835 /*
836 * insert both the head node and the new ref without dropping
837 * the spin lock
838 */
839 head_ref = add_delayed_ref_head(fs_info, trans, &head_ref->node,
840 bytenr, num_bytes, action, 1);
841
842 add_delayed_data_ref(fs_info, trans, head_ref, &ref->node, bytenr,
843 num_bytes, parent, ref_root, owner, offset,
844 action, for_cow);
845 spin_unlock(&delayed_refs->lock);
846 if (need_ref_seq(for_cow, ref_root))
847 btrfs_qgroup_record_ref(trans, &ref->node, extent_op);
848
849 return 0;
850}
851
852int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
853 struct btrfs_trans_handle *trans,
854 u64 bytenr, u64 num_bytes,
855 struct btrfs_delayed_extent_op *extent_op)
856{
857 struct btrfs_delayed_ref_head *head_ref;
858 struct btrfs_delayed_ref_root *delayed_refs;
859
860 head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
861 if (!head_ref)
862 return -ENOMEM;
863
864 head_ref->extent_op = extent_op;
865
866 delayed_refs = &trans->transaction->delayed_refs;
867 spin_lock(&delayed_refs->lock);
868
869 add_delayed_ref_head(fs_info, trans, &head_ref->node, bytenr,
870 num_bytes, BTRFS_UPDATE_DELAYED_HEAD,
871 extent_op->is_data);
872
873 spin_unlock(&delayed_refs->lock);
874 return 0;
875}
876
877/*
878 * this does a simple search for the head node for a given extent.
879 * It must be called with the delayed ref spinlock held, and it returns
880 * the head node if any where found, or NULL if not.
881 */
882struct btrfs_delayed_ref_head *
883btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr)
884{
885 struct btrfs_delayed_ref_root *delayed_refs;
886
887 delayed_refs = &trans->transaction->delayed_refs;
888 return find_ref_head(&delayed_refs->href_root, bytenr, 0);
889}
890
891void btrfs_delayed_ref_exit(void)
892{
893 if (btrfs_delayed_ref_head_cachep)
894 kmem_cache_destroy(btrfs_delayed_ref_head_cachep);
895 if (btrfs_delayed_tree_ref_cachep)
896 kmem_cache_destroy(btrfs_delayed_tree_ref_cachep);
897 if (btrfs_delayed_data_ref_cachep)
898 kmem_cache_destroy(btrfs_delayed_data_ref_cachep);
899 if (btrfs_delayed_extent_op_cachep)
900 kmem_cache_destroy(btrfs_delayed_extent_op_cachep);
901}
902
903int btrfs_delayed_ref_init(void)
904{
905 btrfs_delayed_ref_head_cachep = kmem_cache_create(
906 "btrfs_delayed_ref_head",
907 sizeof(struct btrfs_delayed_ref_head), 0,
908 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
909 if (!btrfs_delayed_ref_head_cachep)
910 goto fail;
911
912 btrfs_delayed_tree_ref_cachep = kmem_cache_create(
913 "btrfs_delayed_tree_ref",
914 sizeof(struct btrfs_delayed_tree_ref), 0,
915 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
916 if (!btrfs_delayed_tree_ref_cachep)
917 goto fail;
918
919 btrfs_delayed_data_ref_cachep = kmem_cache_create(
920 "btrfs_delayed_data_ref",
921 sizeof(struct btrfs_delayed_data_ref), 0,
922 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
923 if (!btrfs_delayed_data_ref_cachep)
924 goto fail;
925
926 btrfs_delayed_extent_op_cachep = kmem_cache_create(
927 "btrfs_delayed_extent_op",
928 sizeof(struct btrfs_delayed_extent_op), 0,
929 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
930 if (!btrfs_delayed_extent_op_cachep)
931 goto fail;
932
933 return 0;
934fail:
935 btrfs_delayed_ref_exit();
936 return -ENOMEM;
937}