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