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