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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#include "qgroup.h"
26
27struct kmem_cache *btrfs_delayed_ref_head_cachep;
28struct kmem_cache *btrfs_delayed_tree_ref_cachep;
29struct kmem_cache *btrfs_delayed_data_ref_cachep;
30struct kmem_cache *btrfs_delayed_extent_op_cachep;
31/*
32 * delayed back reference update tracking. For subvolume trees
33 * we queue up extent allocations and backref maintenance for
34 * delayed processing. This avoids deep call chains where we
35 * add extents in the middle of btrfs_search_slot, and it allows
36 * us to buffer up frequently modified backrefs in an rb tree instead
37 * of hammering updates on the extent allocation tree.
38 */
39
40/*
41 * compare two delayed tree backrefs with same bytenr and type
42 */
43static int comp_tree_refs(struct btrfs_delayed_tree_ref *ref2,
44 struct btrfs_delayed_tree_ref *ref1, int type)
45{
46 if (type == BTRFS_TREE_BLOCK_REF_KEY) {
47 if (ref1->root < ref2->root)
48 return -1;
49 if (ref1->root > ref2->root)
50 return 1;
51 } else {
52 if (ref1->parent < ref2->parent)
53 return -1;
54 if (ref1->parent > ref2->parent)
55 return 1;
56 }
57 return 0;
58}
59
60/*
61 * compare two delayed data backrefs with same bytenr and type
62 */
63static int comp_data_refs(struct btrfs_delayed_data_ref *ref2,
64 struct btrfs_delayed_data_ref *ref1)
65{
66 if (ref1->node.type == BTRFS_EXTENT_DATA_REF_KEY) {
67 if (ref1->root < ref2->root)
68 return -1;
69 if (ref1->root > ref2->root)
70 return 1;
71 if (ref1->objectid < ref2->objectid)
72 return -1;
73 if (ref1->objectid > ref2->objectid)
74 return 1;
75 if (ref1->offset < ref2->offset)
76 return -1;
77 if (ref1->offset > ref2->offset)
78 return 1;
79 } else {
80 if (ref1->parent < ref2->parent)
81 return -1;
82 if (ref1->parent > ref2->parent)
83 return 1;
84 }
85 return 0;
86}
87
88/* insert a new ref to head ref rbtree */
89static struct btrfs_delayed_ref_head *htree_insert(struct rb_root *root,
90 struct rb_node *node)
91{
92 struct rb_node **p = &root->rb_node;
93 struct rb_node *parent_node = NULL;
94 struct btrfs_delayed_ref_head *entry;
95 struct btrfs_delayed_ref_head *ins;
96 u64 bytenr;
97
98 ins = rb_entry(node, struct btrfs_delayed_ref_head, href_node);
99 bytenr = ins->node.bytenr;
100 while (*p) {
101 parent_node = *p;
102 entry = rb_entry(parent_node, struct btrfs_delayed_ref_head,
103 href_node);
104
105 if (bytenr < entry->node.bytenr)
106 p = &(*p)->rb_left;
107 else if (bytenr > entry->node.bytenr)
108 p = &(*p)->rb_right;
109 else
110 return entry;
111 }
112
113 rb_link_node(node, parent_node, p);
114 rb_insert_color(node, root);
115 return NULL;
116}
117
118/*
119 * find an head entry based on bytenr. This returns the delayed ref
120 * head if it was able to find one, or NULL if nothing was in that spot.
121 * If return_bigger is given, the next bigger entry is returned if no exact
122 * match is found.
123 */
124static struct btrfs_delayed_ref_head *
125find_ref_head(struct rb_root *root, u64 bytenr,
126 int return_bigger)
127{
128 struct rb_node *n;
129 struct btrfs_delayed_ref_head *entry;
130
131 n = root->rb_node;
132 entry = NULL;
133 while (n) {
134 entry = rb_entry(n, struct btrfs_delayed_ref_head, href_node);
135
136 if (bytenr < entry->node.bytenr)
137 n = n->rb_left;
138 else if (bytenr > entry->node.bytenr)
139 n = n->rb_right;
140 else
141 return entry;
142 }
143 if (entry && return_bigger) {
144 if (bytenr > entry->node.bytenr) {
145 n = rb_next(&entry->href_node);
146 if (!n)
147 n = rb_first(root);
148 entry = rb_entry(n, struct btrfs_delayed_ref_head,
149 href_node);
150 return entry;
151 }
152 return entry;
153 }
154 return NULL;
155}
156
157int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
158 struct btrfs_delayed_ref_head *head)
159{
160 struct btrfs_delayed_ref_root *delayed_refs;
161
162 delayed_refs = &trans->transaction->delayed_refs;
163 assert_spin_locked(&delayed_refs->lock);
164 if (mutex_trylock(&head->mutex))
165 return 0;
166
167 atomic_inc(&head->node.refs);
168 spin_unlock(&delayed_refs->lock);
169
170 mutex_lock(&head->mutex);
171 spin_lock(&delayed_refs->lock);
172 if (!head->node.in_tree) {
173 mutex_unlock(&head->mutex);
174 btrfs_put_delayed_ref(&head->node);
175 return -EAGAIN;
176 }
177 btrfs_put_delayed_ref(&head->node);
178 return 0;
179}
180
181static inline void drop_delayed_ref(struct btrfs_trans_handle *trans,
182 struct btrfs_delayed_ref_root *delayed_refs,
183 struct btrfs_delayed_ref_head *head,
184 struct btrfs_delayed_ref_node *ref)
185{
186 if (btrfs_delayed_ref_is_head(ref)) {
187 head = btrfs_delayed_node_to_head(ref);
188 rb_erase(&head->href_node, &delayed_refs->href_root);
189 } else {
190 assert_spin_locked(&head->lock);
191 list_del(&ref->list);
192 if (!list_empty(&ref->add_list))
193 list_del(&ref->add_list);
194 }
195 ref->in_tree = 0;
196 btrfs_put_delayed_ref(ref);
197 atomic_dec(&delayed_refs->num_entries);
198 if (trans->delayed_ref_updates)
199 trans->delayed_ref_updates--;
200}
201
202static bool merge_ref(struct btrfs_trans_handle *trans,
203 struct btrfs_delayed_ref_root *delayed_refs,
204 struct btrfs_delayed_ref_head *head,
205 struct btrfs_delayed_ref_node *ref,
206 u64 seq)
207{
208 struct btrfs_delayed_ref_node *next;
209 bool done = false;
210
211 next = list_first_entry(&head->ref_list, struct btrfs_delayed_ref_node,
212 list);
213 while (!done && &next->list != &head->ref_list) {
214 int mod;
215 struct btrfs_delayed_ref_node *next2;
216
217 next2 = list_next_entry(next, list);
218
219 if (next == ref)
220 goto next;
221
222 if (seq && next->seq >= seq)
223 goto next;
224
225 if (next->type != ref->type)
226 goto next;
227
228 if ((ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
229 ref->type == BTRFS_SHARED_BLOCK_REF_KEY) &&
230 comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref),
231 btrfs_delayed_node_to_tree_ref(next),
232 ref->type))
233 goto next;
234 if ((ref->type == BTRFS_EXTENT_DATA_REF_KEY ||
235 ref->type == BTRFS_SHARED_DATA_REF_KEY) &&
236 comp_data_refs(btrfs_delayed_node_to_data_ref(ref),
237 btrfs_delayed_node_to_data_ref(next)))
238 goto next;
239
240 if (ref->action == next->action) {
241 mod = next->ref_mod;
242 } else {
243 if (ref->ref_mod < next->ref_mod) {
244 swap(ref, next);
245 done = true;
246 }
247 mod = -next->ref_mod;
248 }
249
250 drop_delayed_ref(trans, delayed_refs, head, next);
251 ref->ref_mod += mod;
252 if (ref->ref_mod == 0) {
253 drop_delayed_ref(trans, delayed_refs, head, ref);
254 done = true;
255 } else {
256 /*
257 * Can't have multiples of the same ref on a tree block.
258 */
259 WARN_ON(ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
260 ref->type == BTRFS_SHARED_BLOCK_REF_KEY);
261 }
262next:
263 next = next2;
264 }
265
266 return done;
267}
268
269void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
270 struct btrfs_fs_info *fs_info,
271 struct btrfs_delayed_ref_root *delayed_refs,
272 struct btrfs_delayed_ref_head *head)
273{
274 struct btrfs_delayed_ref_node *ref;
275 u64 seq = 0;
276
277 assert_spin_locked(&head->lock);
278
279 if (list_empty(&head->ref_list))
280 return;
281
282 /* We don't have too many refs to merge for data. */
283 if (head->is_data)
284 return;
285
286 spin_lock(&fs_info->tree_mod_seq_lock);
287 if (!list_empty(&fs_info->tree_mod_seq_list)) {
288 struct seq_list *elem;
289
290 elem = list_first_entry(&fs_info->tree_mod_seq_list,
291 struct seq_list, list);
292 seq = elem->seq;
293 }
294 spin_unlock(&fs_info->tree_mod_seq_lock);
295
296 ref = list_first_entry(&head->ref_list, struct btrfs_delayed_ref_node,
297 list);
298 while (&ref->list != &head->ref_list) {
299 if (seq && ref->seq >= seq)
300 goto next;
301
302 if (merge_ref(trans, delayed_refs, head, ref, seq)) {
303 if (list_empty(&head->ref_list))
304 break;
305 ref = list_first_entry(&head->ref_list,
306 struct btrfs_delayed_ref_node,
307 list);
308 continue;
309 }
310next:
311 ref = list_next_entry(ref, list);
312 }
313}
314
315int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
316 struct btrfs_delayed_ref_root *delayed_refs,
317 u64 seq)
318{
319 struct seq_list *elem;
320 int ret = 0;
321
322 spin_lock(&fs_info->tree_mod_seq_lock);
323 if (!list_empty(&fs_info->tree_mod_seq_list)) {
324 elem = list_first_entry(&fs_info->tree_mod_seq_list,
325 struct seq_list, list);
326 if (seq >= elem->seq) {
327 btrfs_debug(fs_info,
328 "holding back delayed_ref %#x.%x, lowest is %#x.%x (%p)",
329 (u32)(seq >> 32), (u32)seq,
330 (u32)(elem->seq >> 32), (u32)elem->seq,
331 delayed_refs);
332 ret = 1;
333 }
334 }
335
336 spin_unlock(&fs_info->tree_mod_seq_lock);
337 return ret;
338}
339
340struct btrfs_delayed_ref_head *
341btrfs_select_ref_head(struct btrfs_trans_handle *trans)
342{
343 struct btrfs_delayed_ref_root *delayed_refs;
344 struct btrfs_delayed_ref_head *head;
345 u64 start;
346 bool loop = false;
347
348 delayed_refs = &trans->transaction->delayed_refs;
349
350again:
351 start = delayed_refs->run_delayed_start;
352 head = find_ref_head(&delayed_refs->href_root, start, 1);
353 if (!head && !loop) {
354 delayed_refs->run_delayed_start = 0;
355 start = 0;
356 loop = true;
357 head = find_ref_head(&delayed_refs->href_root, start, 1);
358 if (!head)
359 return NULL;
360 } else if (!head && loop) {
361 return NULL;
362 }
363
364 while (head->processing) {
365 struct rb_node *node;
366
367 node = rb_next(&head->href_node);
368 if (!node) {
369 if (loop)
370 return NULL;
371 delayed_refs->run_delayed_start = 0;
372 start = 0;
373 loop = true;
374 goto again;
375 }
376 head = rb_entry(node, struct btrfs_delayed_ref_head,
377 href_node);
378 }
379
380 head->processing = 1;
381 WARN_ON(delayed_refs->num_heads_ready == 0);
382 delayed_refs->num_heads_ready--;
383 delayed_refs->run_delayed_start = head->node.bytenr +
384 head->node.num_bytes;
385 return head;
386}
387
388/*
389 * Helper to insert the ref_node to the tail or merge with tail.
390 *
391 * Return 0 for insert.
392 * Return >0 for merge.
393 */
394static int
395add_delayed_ref_tail_merge(struct btrfs_trans_handle *trans,
396 struct btrfs_delayed_ref_root *root,
397 struct btrfs_delayed_ref_head *href,
398 struct btrfs_delayed_ref_node *ref)
399{
400 struct btrfs_delayed_ref_node *exist;
401 int mod;
402 int ret = 0;
403
404 spin_lock(&href->lock);
405 /* Check whether we can merge the tail node with ref */
406 if (list_empty(&href->ref_list))
407 goto add_tail;
408 exist = list_entry(href->ref_list.prev, struct btrfs_delayed_ref_node,
409 list);
410 /* No need to compare bytenr nor is_head */
411 if (exist->type != ref->type || exist->seq != ref->seq)
412 goto add_tail;
413
414 if ((exist->type == BTRFS_TREE_BLOCK_REF_KEY ||
415 exist->type == BTRFS_SHARED_BLOCK_REF_KEY) &&
416 comp_tree_refs(btrfs_delayed_node_to_tree_ref(exist),
417 btrfs_delayed_node_to_tree_ref(ref),
418 ref->type))
419 goto add_tail;
420 if ((exist->type == BTRFS_EXTENT_DATA_REF_KEY ||
421 exist->type == BTRFS_SHARED_DATA_REF_KEY) &&
422 comp_data_refs(btrfs_delayed_node_to_data_ref(exist),
423 btrfs_delayed_node_to_data_ref(ref)))
424 goto add_tail;
425
426 /* Now we are sure we can merge */
427 ret = 1;
428 if (exist->action == ref->action) {
429 mod = ref->ref_mod;
430 } else {
431 /* Need to change action */
432 if (exist->ref_mod < ref->ref_mod) {
433 exist->action = ref->action;
434 mod = -exist->ref_mod;
435 exist->ref_mod = ref->ref_mod;
436 if (ref->action == BTRFS_ADD_DELAYED_REF)
437 list_add_tail(&exist->add_list,
438 &href->ref_add_list);
439 else if (ref->action == BTRFS_DROP_DELAYED_REF) {
440 ASSERT(!list_empty(&exist->add_list));
441 list_del(&exist->add_list);
442 } else {
443 ASSERT(0);
444 }
445 } else
446 mod = -ref->ref_mod;
447 }
448 exist->ref_mod += mod;
449
450 /* remove existing tail if its ref_mod is zero */
451 if (exist->ref_mod == 0)
452 drop_delayed_ref(trans, root, href, exist);
453 spin_unlock(&href->lock);
454 return ret;
455
456add_tail:
457 list_add_tail(&ref->list, &href->ref_list);
458 if (ref->action == BTRFS_ADD_DELAYED_REF)
459 list_add_tail(&ref->add_list, &href->ref_add_list);
460 atomic_inc(&root->num_entries);
461 trans->delayed_ref_updates++;
462 spin_unlock(&href->lock);
463 return ret;
464}
465
466/*
467 * helper function to update the accounting in the head ref
468 * existing and update must have the same bytenr
469 */
470static noinline void
471update_existing_head_ref(struct btrfs_delayed_ref_root *delayed_refs,
472 struct btrfs_delayed_ref_node *existing,
473 struct btrfs_delayed_ref_node *update)
474{
475 struct btrfs_delayed_ref_head *existing_ref;
476 struct btrfs_delayed_ref_head *ref;
477 int old_ref_mod;
478
479 existing_ref = btrfs_delayed_node_to_head(existing);
480 ref = btrfs_delayed_node_to_head(update);
481 BUG_ON(existing_ref->is_data != ref->is_data);
482
483 spin_lock(&existing_ref->lock);
484 if (ref->must_insert_reserved) {
485 /* if the extent was freed and then
486 * reallocated before the delayed ref
487 * entries were processed, we can end up
488 * with an existing head ref without
489 * the must_insert_reserved flag set.
490 * Set it again here
491 */
492 existing_ref->must_insert_reserved = ref->must_insert_reserved;
493
494 /*
495 * update the num_bytes so we make sure the accounting
496 * is done correctly
497 */
498 existing->num_bytes = update->num_bytes;
499
500 }
501
502 if (ref->extent_op) {
503 if (!existing_ref->extent_op) {
504 existing_ref->extent_op = ref->extent_op;
505 } else {
506 if (ref->extent_op->update_key) {
507 memcpy(&existing_ref->extent_op->key,
508 &ref->extent_op->key,
509 sizeof(ref->extent_op->key));
510 existing_ref->extent_op->update_key = true;
511 }
512 if (ref->extent_op->update_flags) {
513 existing_ref->extent_op->flags_to_set |=
514 ref->extent_op->flags_to_set;
515 existing_ref->extent_op->update_flags = true;
516 }
517 btrfs_free_delayed_extent_op(ref->extent_op);
518 }
519 }
520 /*
521 * update the reference mod on the head to reflect this new operation,
522 * only need the lock for this case cause we could be processing it
523 * currently, for refs we just added we know we're a-ok.
524 */
525 old_ref_mod = existing_ref->total_ref_mod;
526 existing->ref_mod += update->ref_mod;
527 existing_ref->total_ref_mod += update->ref_mod;
528
529 /*
530 * If we are going to from a positive ref mod to a negative or vice
531 * versa we need to make sure to adjust pending_csums accordingly.
532 */
533 if (existing_ref->is_data) {
534 if (existing_ref->total_ref_mod >= 0 && old_ref_mod < 0)
535 delayed_refs->pending_csums -= existing->num_bytes;
536 if (existing_ref->total_ref_mod < 0 && old_ref_mod >= 0)
537 delayed_refs->pending_csums += existing->num_bytes;
538 }
539 spin_unlock(&existing_ref->lock);
540}
541
542/*
543 * helper function to actually insert a head node into the rbtree.
544 * this does all the dirty work in terms of maintaining the correct
545 * overall modification count.
546 */
547static noinline struct btrfs_delayed_ref_head *
548add_delayed_ref_head(struct btrfs_fs_info *fs_info,
549 struct btrfs_trans_handle *trans,
550 struct btrfs_delayed_ref_node *ref,
551 struct btrfs_qgroup_extent_record *qrecord,
552 u64 bytenr, u64 num_bytes, u64 ref_root, u64 reserved,
553 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 /* If reserved is provided, it must be a data extent. */
562 BUG_ON(!is_data && reserved);
563
564 /*
565 * the head node stores the sum of all the mods, so dropping a ref
566 * should drop the sum in the head node by one.
567 */
568 if (action == BTRFS_UPDATE_DELAYED_HEAD)
569 count_mod = 0;
570 else if (action == BTRFS_DROP_DELAYED_REF)
571 count_mod = -1;
572
573 /*
574 * BTRFS_ADD_DELAYED_EXTENT means that we need to update
575 * the reserved accounting when the extent is finally added, or
576 * if a later modification deletes the delayed ref without ever
577 * inserting the extent into the extent allocation tree.
578 * ref->must_insert_reserved is the flag used to record
579 * that accounting mods are required.
580 *
581 * Once we record must_insert_reserved, switch the action to
582 * BTRFS_ADD_DELAYED_REF because other special casing is not required.
583 */
584 if (action == BTRFS_ADD_DELAYED_EXTENT)
585 must_insert_reserved = 1;
586 else
587 must_insert_reserved = 0;
588
589 delayed_refs = &trans->transaction->delayed_refs;
590
591 /* first set the basic ref node struct up */
592 atomic_set(&ref->refs, 1);
593 ref->bytenr = bytenr;
594 ref->num_bytes = num_bytes;
595 ref->ref_mod = count_mod;
596 ref->type = 0;
597 ref->action = 0;
598 ref->is_head = 1;
599 ref->in_tree = 1;
600 ref->seq = 0;
601
602 head_ref = btrfs_delayed_node_to_head(ref);
603 head_ref->must_insert_reserved = must_insert_reserved;
604 head_ref->is_data = is_data;
605 INIT_LIST_HEAD(&head_ref->ref_list);
606 INIT_LIST_HEAD(&head_ref->ref_add_list);
607 head_ref->processing = 0;
608 head_ref->total_ref_mod = count_mod;
609 head_ref->qgroup_reserved = 0;
610 head_ref->qgroup_ref_root = 0;
611
612 /* Record qgroup extent info if provided */
613 if (qrecord) {
614 if (ref_root && reserved) {
615 head_ref->qgroup_ref_root = ref_root;
616 head_ref->qgroup_reserved = reserved;
617 }
618
619 qrecord->bytenr = bytenr;
620 qrecord->num_bytes = num_bytes;
621 qrecord->old_roots = NULL;
622
623 if(btrfs_qgroup_trace_extent_nolock(fs_info,
624 delayed_refs, qrecord))
625 kfree(qrecord);
626 }
627
628 spin_lock_init(&head_ref->lock);
629 mutex_init(&head_ref->mutex);
630
631 trace_add_delayed_ref_head(fs_info, ref, head_ref, action);
632
633 existing = htree_insert(&delayed_refs->href_root,
634 &head_ref->href_node);
635 if (existing) {
636 WARN_ON(ref_root && reserved && existing->qgroup_ref_root
637 && existing->qgroup_reserved);
638 update_existing_head_ref(delayed_refs, &existing->node, ref);
639 /*
640 * we've updated the existing ref, free the newly
641 * allocated ref
642 */
643 kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
644 head_ref = existing;
645 } else {
646 if (is_data && count_mod < 0)
647 delayed_refs->pending_csums += num_bytes;
648 delayed_refs->num_heads++;
649 delayed_refs->num_heads_ready++;
650 atomic_inc(&delayed_refs->num_entries);
651 trans->delayed_ref_updates++;
652 }
653 return head_ref;
654}
655
656/*
657 * helper to insert a delayed tree ref into the rbtree.
658 */
659static noinline void
660add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
661 struct btrfs_trans_handle *trans,
662 struct btrfs_delayed_ref_head *head_ref,
663 struct btrfs_delayed_ref_node *ref, u64 bytenr,
664 u64 num_bytes, u64 parent, u64 ref_root, int level,
665 int action)
666{
667 struct btrfs_delayed_tree_ref *full_ref;
668 struct btrfs_delayed_ref_root *delayed_refs;
669 u64 seq = 0;
670 int ret;
671
672 if (action == BTRFS_ADD_DELAYED_EXTENT)
673 action = BTRFS_ADD_DELAYED_REF;
674
675 if (is_fstree(ref_root))
676 seq = atomic64_read(&fs_info->tree_mod_seq);
677 delayed_refs = &trans->transaction->delayed_refs;
678
679 /* first set the basic ref node struct up */
680 atomic_set(&ref->refs, 1);
681 ref->bytenr = bytenr;
682 ref->num_bytes = num_bytes;
683 ref->ref_mod = 1;
684 ref->action = action;
685 ref->is_head = 0;
686 ref->in_tree = 1;
687 ref->seq = seq;
688 INIT_LIST_HEAD(&ref->list);
689 INIT_LIST_HEAD(&ref->add_list);
690
691 full_ref = btrfs_delayed_node_to_tree_ref(ref);
692 full_ref->parent = parent;
693 full_ref->root = ref_root;
694 if (parent)
695 ref->type = BTRFS_SHARED_BLOCK_REF_KEY;
696 else
697 ref->type = BTRFS_TREE_BLOCK_REF_KEY;
698 full_ref->level = level;
699
700 trace_add_delayed_tree_ref(fs_info, ref, full_ref, action);
701
702 ret = add_delayed_ref_tail_merge(trans, delayed_refs, head_ref, ref);
703
704 /*
705 * XXX: memory should be freed at the same level allocated.
706 * But bad practice is anywhere... Follow it now. Need cleanup.
707 */
708 if (ret > 0)
709 kmem_cache_free(btrfs_delayed_tree_ref_cachep, full_ref);
710}
711
712/*
713 * helper to insert a delayed data ref into the rbtree.
714 */
715static noinline void
716add_delayed_data_ref(struct btrfs_fs_info *fs_info,
717 struct btrfs_trans_handle *trans,
718 struct btrfs_delayed_ref_head *head_ref,
719 struct btrfs_delayed_ref_node *ref, u64 bytenr,
720 u64 num_bytes, u64 parent, u64 ref_root, u64 owner,
721 u64 offset, int action)
722{
723 struct btrfs_delayed_data_ref *full_ref;
724 struct btrfs_delayed_ref_root *delayed_refs;
725 u64 seq = 0;
726 int ret;
727
728 if (action == BTRFS_ADD_DELAYED_EXTENT)
729 action = BTRFS_ADD_DELAYED_REF;
730
731 delayed_refs = &trans->transaction->delayed_refs;
732
733 if (is_fstree(ref_root))
734 seq = atomic64_read(&fs_info->tree_mod_seq);
735
736 /* first set the basic ref node struct up */
737 atomic_set(&ref->refs, 1);
738 ref->bytenr = bytenr;
739 ref->num_bytes = num_bytes;
740 ref->ref_mod = 1;
741 ref->action = action;
742 ref->is_head = 0;
743 ref->in_tree = 1;
744 ref->seq = seq;
745 INIT_LIST_HEAD(&ref->list);
746 INIT_LIST_HEAD(&ref->add_list);
747
748 full_ref = btrfs_delayed_node_to_data_ref(ref);
749 full_ref->parent = parent;
750 full_ref->root = ref_root;
751 if (parent)
752 ref->type = BTRFS_SHARED_DATA_REF_KEY;
753 else
754 ref->type = BTRFS_EXTENT_DATA_REF_KEY;
755
756 full_ref->objectid = owner;
757 full_ref->offset = offset;
758
759 trace_add_delayed_data_ref(fs_info, ref, full_ref, action);
760
761 ret = add_delayed_ref_tail_merge(trans, delayed_refs, head_ref, ref);
762
763 if (ret > 0)
764 kmem_cache_free(btrfs_delayed_data_ref_cachep, full_ref);
765}
766
767/*
768 * add a delayed tree ref. This does all of the accounting required
769 * to make sure the delayed ref is eventually processed before this
770 * transaction commits.
771 */
772int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
773 struct btrfs_trans_handle *trans,
774 u64 bytenr, u64 num_bytes, u64 parent,
775 u64 ref_root, int level, int action,
776 struct btrfs_delayed_extent_op *extent_op)
777{
778 struct btrfs_delayed_tree_ref *ref;
779 struct btrfs_delayed_ref_head *head_ref;
780 struct btrfs_delayed_ref_root *delayed_refs;
781 struct btrfs_qgroup_extent_record *record = NULL;
782
783 BUG_ON(extent_op && extent_op->is_data);
784 ref = kmem_cache_alloc(btrfs_delayed_tree_ref_cachep, GFP_NOFS);
785 if (!ref)
786 return -ENOMEM;
787
788 head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
789 if (!head_ref)
790 goto free_ref;
791
792 if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) &&
793 is_fstree(ref_root)) {
794 record = kmalloc(sizeof(*record), GFP_NOFS);
795 if (!record)
796 goto free_head_ref;
797 }
798
799 head_ref->extent_op = extent_op;
800
801 delayed_refs = &trans->transaction->delayed_refs;
802 spin_lock(&delayed_refs->lock);
803
804 /*
805 * insert both the head node and the new ref without dropping
806 * the spin lock
807 */
808 head_ref = add_delayed_ref_head(fs_info, trans, &head_ref->node, record,
809 bytenr, num_bytes, 0, 0, action, 0);
810
811 add_delayed_tree_ref(fs_info, trans, head_ref, &ref->node, bytenr,
812 num_bytes, parent, ref_root, level, action);
813 spin_unlock(&delayed_refs->lock);
814
815 return 0;
816
817free_head_ref:
818 kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
819free_ref:
820 kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
821
822 return -ENOMEM;
823}
824
825/*
826 * add a delayed data ref. it's similar to btrfs_add_delayed_tree_ref.
827 */
828int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
829 struct btrfs_trans_handle *trans,
830 u64 bytenr, u64 num_bytes,
831 u64 parent, u64 ref_root,
832 u64 owner, u64 offset, u64 reserved, int action,
833 struct btrfs_delayed_extent_op *extent_op)
834{
835 struct btrfs_delayed_data_ref *ref;
836 struct btrfs_delayed_ref_head *head_ref;
837 struct btrfs_delayed_ref_root *delayed_refs;
838 struct btrfs_qgroup_extent_record *record = NULL;
839
840 BUG_ON(extent_op && !extent_op->is_data);
841 ref = kmem_cache_alloc(btrfs_delayed_data_ref_cachep, GFP_NOFS);
842 if (!ref)
843 return -ENOMEM;
844
845 head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
846 if (!head_ref) {
847 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
848 return -ENOMEM;
849 }
850
851 if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) &&
852 is_fstree(ref_root)) {
853 record = kmalloc(sizeof(*record), GFP_NOFS);
854 if (!record) {
855 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
856 kmem_cache_free(btrfs_delayed_ref_head_cachep,
857 head_ref);
858 return -ENOMEM;
859 }
860 }
861
862 head_ref->extent_op = extent_op;
863
864 delayed_refs = &trans->transaction->delayed_refs;
865 spin_lock(&delayed_refs->lock);
866
867 /*
868 * insert both the head node and the new ref without dropping
869 * the spin lock
870 */
871 head_ref = add_delayed_ref_head(fs_info, trans, &head_ref->node, record,
872 bytenr, num_bytes, ref_root, reserved,
873 action, 1);
874
875 add_delayed_data_ref(fs_info, trans, head_ref, &ref->node, bytenr,
876 num_bytes, parent, ref_root, owner, offset,
877 action);
878 spin_unlock(&delayed_refs->lock);
879
880 return 0;
881}
882
883int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
884 struct btrfs_trans_handle *trans,
885 u64 bytenr, u64 num_bytes,
886 struct btrfs_delayed_extent_op *extent_op)
887{
888 struct btrfs_delayed_ref_head *head_ref;
889 struct btrfs_delayed_ref_root *delayed_refs;
890
891 head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
892 if (!head_ref)
893 return -ENOMEM;
894
895 head_ref->extent_op = extent_op;
896
897 delayed_refs = &trans->transaction->delayed_refs;
898 spin_lock(&delayed_refs->lock);
899
900 add_delayed_ref_head(fs_info, trans, &head_ref->node, NULL, bytenr,
901 num_bytes, 0, 0, BTRFS_UPDATE_DELAYED_HEAD,
902 extent_op->is_data);
903
904 spin_unlock(&delayed_refs->lock);
905 return 0;
906}
907
908/*
909 * this does a simple search for the head node for a given extent.
910 * It must be called with the delayed ref spinlock held, and it returns
911 * the head node if any where found, or NULL if not.
912 */
913struct btrfs_delayed_ref_head *
914btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr)
915{
916 struct btrfs_delayed_ref_root *delayed_refs;
917
918 delayed_refs = &trans->transaction->delayed_refs;
919 return find_ref_head(&delayed_refs->href_root, bytenr, 0);
920}
921
922void btrfs_delayed_ref_exit(void)
923{
924 kmem_cache_destroy(btrfs_delayed_ref_head_cachep);
925 kmem_cache_destroy(btrfs_delayed_tree_ref_cachep);
926 kmem_cache_destroy(btrfs_delayed_data_ref_cachep);
927 kmem_cache_destroy(btrfs_delayed_extent_op_cachep);
928}
929
930int btrfs_delayed_ref_init(void)
931{
932 btrfs_delayed_ref_head_cachep = kmem_cache_create(
933 "btrfs_delayed_ref_head",
934 sizeof(struct btrfs_delayed_ref_head), 0,
935 SLAB_MEM_SPREAD, NULL);
936 if (!btrfs_delayed_ref_head_cachep)
937 goto fail;
938
939 btrfs_delayed_tree_ref_cachep = kmem_cache_create(
940 "btrfs_delayed_tree_ref",
941 sizeof(struct btrfs_delayed_tree_ref), 0,
942 SLAB_MEM_SPREAD, NULL);
943 if (!btrfs_delayed_tree_ref_cachep)
944 goto fail;
945
946 btrfs_delayed_data_ref_cachep = kmem_cache_create(
947 "btrfs_delayed_data_ref",
948 sizeof(struct btrfs_delayed_data_ref), 0,
949 SLAB_MEM_SPREAD, NULL);
950 if (!btrfs_delayed_data_ref_cachep)
951 goto fail;
952
953 btrfs_delayed_extent_op_cachep = kmem_cache_create(
954 "btrfs_delayed_extent_op",
955 sizeof(struct btrfs_delayed_extent_op), 0,
956 SLAB_MEM_SPREAD, NULL);
957 if (!btrfs_delayed_extent_op_cachep)
958 goto fail;
959
960 return 0;
961fail:
962 btrfs_delayed_ref_exit();
963 return -ENOMEM;
964}