btrfs: Streamline memory allocation failure handling in btrfs_add_delayed_tree_ref
[sfrench/cifs-2.6.git] / fs / btrfs / delayed-ref.c
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
14 struct kmem_cache *btrfs_delayed_ref_head_cachep;
15 struct kmem_cache *btrfs_delayed_tree_ref_cachep;
16 struct kmem_cache *btrfs_delayed_data_ref_cachep;
17 struct kmem_cache *btrfs_delayed_extent_op_cachep;
18 /*
19  * delayed back reference update tracking.  For subvolume trees
20  * we queue up extent allocations and backref maintenance for
21  * delayed processing.   This avoids deep call chains where we
22  * add extents in the middle of btrfs_search_slot, and it allows
23  * us to buffer up frequently modified backrefs in an rb tree instead
24  * of hammering updates on the extent allocation tree.
25  */
26
27 /*
28  * compare two delayed tree backrefs with same bytenr and type
29  */
30 static int comp_tree_refs(struct btrfs_delayed_tree_ref *ref1,
31                           struct btrfs_delayed_tree_ref *ref2)
32 {
33         if (ref1->node.type == BTRFS_TREE_BLOCK_REF_KEY) {
34                 if (ref1->root < ref2->root)
35                         return -1;
36                 if (ref1->root > ref2->root)
37                         return 1;
38         } else {
39                 if (ref1->parent < ref2->parent)
40                         return -1;
41                 if (ref1->parent > ref2->parent)
42                         return 1;
43         }
44         return 0;
45 }
46
47 /*
48  * compare two delayed data backrefs with same bytenr and type
49  */
50 static int comp_data_refs(struct btrfs_delayed_data_ref *ref1,
51                           struct btrfs_delayed_data_ref *ref2)
52 {
53         if (ref1->node.type == BTRFS_EXTENT_DATA_REF_KEY) {
54                 if (ref1->root < ref2->root)
55                         return -1;
56                 if (ref1->root > ref2->root)
57                         return 1;
58                 if (ref1->objectid < ref2->objectid)
59                         return -1;
60                 if (ref1->objectid > ref2->objectid)
61                         return 1;
62                 if (ref1->offset < ref2->offset)
63                         return -1;
64                 if (ref1->offset > ref2->offset)
65                         return 1;
66         } else {
67                 if (ref1->parent < ref2->parent)
68                         return -1;
69                 if (ref1->parent > ref2->parent)
70                         return 1;
71         }
72         return 0;
73 }
74
75 static int comp_refs(struct btrfs_delayed_ref_node *ref1,
76                      struct btrfs_delayed_ref_node *ref2,
77                      bool check_seq)
78 {
79         int ret = 0;
80
81         if (ref1->type < ref2->type)
82                 return -1;
83         if (ref1->type > ref2->type)
84                 return 1;
85         if (ref1->type == BTRFS_TREE_BLOCK_REF_KEY ||
86             ref1->type == BTRFS_SHARED_BLOCK_REF_KEY)
87                 ret = comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref1),
88                                      btrfs_delayed_node_to_tree_ref(ref2));
89         else
90                 ret = comp_data_refs(btrfs_delayed_node_to_data_ref(ref1),
91                                      btrfs_delayed_node_to_data_ref(ref2));
92         if (ret)
93                 return ret;
94         if (check_seq) {
95                 if (ref1->seq < ref2->seq)
96                         return -1;
97                 if (ref1->seq > ref2->seq)
98                         return 1;
99         }
100         return 0;
101 }
102
103 /* insert a new ref to head ref rbtree */
104 static struct btrfs_delayed_ref_head *htree_insert(struct rb_root *root,
105                                                    struct rb_node *node)
106 {
107         struct rb_node **p = &root->rb_node;
108         struct rb_node *parent_node = NULL;
109         struct btrfs_delayed_ref_head *entry;
110         struct btrfs_delayed_ref_head *ins;
111         u64 bytenr;
112
113         ins = rb_entry(node, struct btrfs_delayed_ref_head, href_node);
114         bytenr = ins->bytenr;
115         while (*p) {
116                 parent_node = *p;
117                 entry = rb_entry(parent_node, struct btrfs_delayed_ref_head,
118                                  href_node);
119
120                 if (bytenr < entry->bytenr)
121                         p = &(*p)->rb_left;
122                 else if (bytenr > entry->bytenr)
123                         p = &(*p)->rb_right;
124                 else
125                         return entry;
126         }
127
128         rb_link_node(node, parent_node, p);
129         rb_insert_color(node, root);
130         return NULL;
131 }
132
133 static struct btrfs_delayed_ref_node* tree_insert(struct rb_root *root,
134                 struct btrfs_delayed_ref_node *ins)
135 {
136         struct rb_node **p = &root->rb_node;
137         struct rb_node *node = &ins->ref_node;
138         struct rb_node *parent_node = NULL;
139         struct btrfs_delayed_ref_node *entry;
140
141         while (*p) {
142                 int comp;
143
144                 parent_node = *p;
145                 entry = rb_entry(parent_node, struct btrfs_delayed_ref_node,
146                                  ref_node);
147                 comp = comp_refs(ins, entry, true);
148                 if (comp < 0)
149                         p = &(*p)->rb_left;
150                 else if (comp > 0)
151                         p = &(*p)->rb_right;
152                 else
153                         return entry;
154         }
155
156         rb_link_node(node, parent_node, p);
157         rb_insert_color(node, root);
158         return NULL;
159 }
160
161 /*
162  * find an head entry based on bytenr. This returns the delayed ref
163  * head if it was able to find one, or NULL if nothing was in that spot.
164  * If return_bigger is given, the next bigger entry is returned if no exact
165  * match is found.
166  */
167 static struct btrfs_delayed_ref_head *
168 find_ref_head(struct rb_root *root, u64 bytenr,
169               int return_bigger)
170 {
171         struct rb_node *n;
172         struct btrfs_delayed_ref_head *entry;
173
174         n = root->rb_node;
175         entry = NULL;
176         while (n) {
177                 entry = rb_entry(n, struct btrfs_delayed_ref_head, href_node);
178
179                 if (bytenr < entry->bytenr)
180                         n = n->rb_left;
181                 else if (bytenr > entry->bytenr)
182                         n = n->rb_right;
183                 else
184                         return entry;
185         }
186         if (entry && return_bigger) {
187                 if (bytenr > entry->bytenr) {
188                         n = rb_next(&entry->href_node);
189                         if (!n)
190                                 n = rb_first(root);
191                         entry = rb_entry(n, struct btrfs_delayed_ref_head,
192                                          href_node);
193                         return entry;
194                 }
195                 return entry;
196         }
197         return NULL;
198 }
199
200 int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
201                            struct btrfs_delayed_ref_head *head)
202 {
203         struct btrfs_delayed_ref_root *delayed_refs;
204
205         delayed_refs = &trans->transaction->delayed_refs;
206         lockdep_assert_held(&delayed_refs->lock);
207         if (mutex_trylock(&head->mutex))
208                 return 0;
209
210         refcount_inc(&head->refs);
211         spin_unlock(&delayed_refs->lock);
212
213         mutex_lock(&head->mutex);
214         spin_lock(&delayed_refs->lock);
215         if (RB_EMPTY_NODE(&head->href_node)) {
216                 mutex_unlock(&head->mutex);
217                 btrfs_put_delayed_ref_head(head);
218                 return -EAGAIN;
219         }
220         btrfs_put_delayed_ref_head(head);
221         return 0;
222 }
223
224 static inline void drop_delayed_ref(struct btrfs_trans_handle *trans,
225                                     struct btrfs_delayed_ref_root *delayed_refs,
226                                     struct btrfs_delayed_ref_head *head,
227                                     struct btrfs_delayed_ref_node *ref)
228 {
229         lockdep_assert_held(&head->lock);
230         rb_erase(&ref->ref_node, &head->ref_tree);
231         RB_CLEAR_NODE(&ref->ref_node);
232         if (!list_empty(&ref->add_list))
233                 list_del(&ref->add_list);
234         ref->in_tree = 0;
235         btrfs_put_delayed_ref(ref);
236         atomic_dec(&delayed_refs->num_entries);
237         if (trans->delayed_ref_updates)
238                 trans->delayed_ref_updates--;
239 }
240
241 static bool merge_ref(struct btrfs_trans_handle *trans,
242                       struct btrfs_delayed_ref_root *delayed_refs,
243                       struct btrfs_delayed_ref_head *head,
244                       struct btrfs_delayed_ref_node *ref,
245                       u64 seq)
246 {
247         struct btrfs_delayed_ref_node *next;
248         struct rb_node *node = rb_next(&ref->ref_node);
249         bool done = false;
250
251         while (!done && node) {
252                 int mod;
253
254                 next = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
255                 node = rb_next(node);
256                 if (seq && next->seq >= seq)
257                         break;
258                 if (comp_refs(ref, next, false))
259                         break;
260
261                 if (ref->action == next->action) {
262                         mod = next->ref_mod;
263                 } else {
264                         if (ref->ref_mod < next->ref_mod) {
265                                 swap(ref, next);
266                                 done = true;
267                         }
268                         mod = -next->ref_mod;
269                 }
270
271                 drop_delayed_ref(trans, delayed_refs, head, next);
272                 ref->ref_mod += mod;
273                 if (ref->ref_mod == 0) {
274                         drop_delayed_ref(trans, delayed_refs, head, ref);
275                         done = true;
276                 } else {
277                         /*
278                          * Can't have multiples of the same ref on a tree block.
279                          */
280                         WARN_ON(ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
281                                 ref->type == BTRFS_SHARED_BLOCK_REF_KEY);
282                 }
283         }
284
285         return done;
286 }
287
288 void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
289                               struct btrfs_delayed_ref_root *delayed_refs,
290                               struct btrfs_delayed_ref_head *head)
291 {
292         struct btrfs_fs_info *fs_info = trans->fs_info;
293         struct btrfs_delayed_ref_node *ref;
294         struct rb_node *node;
295         u64 seq = 0;
296
297         lockdep_assert_held(&head->lock);
298
299         if (RB_EMPTY_ROOT(&head->ref_tree))
300                 return;
301
302         /* We don't have too many refs to merge for data. */
303         if (head->is_data)
304                 return;
305
306         spin_lock(&fs_info->tree_mod_seq_lock);
307         if (!list_empty(&fs_info->tree_mod_seq_list)) {
308                 struct seq_list *elem;
309
310                 elem = list_first_entry(&fs_info->tree_mod_seq_list,
311                                         struct seq_list, list);
312                 seq = elem->seq;
313         }
314         spin_unlock(&fs_info->tree_mod_seq_lock);
315
316 again:
317         for (node = rb_first(&head->ref_tree); node; node = rb_next(node)) {
318                 ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
319                 if (seq && ref->seq >= seq)
320                         continue;
321                 if (merge_ref(trans, delayed_refs, head, ref, seq))
322                         goto again;
323         }
324 }
325
326 int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info, u64 seq)
327 {
328         struct seq_list *elem;
329         int ret = 0;
330
331         spin_lock(&fs_info->tree_mod_seq_lock);
332         if (!list_empty(&fs_info->tree_mod_seq_list)) {
333                 elem = list_first_entry(&fs_info->tree_mod_seq_list,
334                                         struct seq_list, list);
335                 if (seq >= elem->seq) {
336                         btrfs_debug(fs_info,
337                                 "holding back delayed_ref %#x.%x, lowest is %#x.%x",
338                                 (u32)(seq >> 32), (u32)seq,
339                                 (u32)(elem->seq >> 32), (u32)elem->seq);
340                         ret = 1;
341                 }
342         }
343
344         spin_unlock(&fs_info->tree_mod_seq_lock);
345         return ret;
346 }
347
348 struct btrfs_delayed_ref_head *
349 btrfs_select_ref_head(struct btrfs_trans_handle *trans)
350 {
351         struct btrfs_delayed_ref_root *delayed_refs;
352         struct btrfs_delayed_ref_head *head;
353         u64 start;
354         bool loop = false;
355
356         delayed_refs = &trans->transaction->delayed_refs;
357
358 again:
359         start = delayed_refs->run_delayed_start;
360         head = find_ref_head(&delayed_refs->href_root, start, 1);
361         if (!head && !loop) {
362                 delayed_refs->run_delayed_start = 0;
363                 start = 0;
364                 loop = true;
365                 head = find_ref_head(&delayed_refs->href_root, start, 1);
366                 if (!head)
367                         return NULL;
368         } else if (!head && loop) {
369                 return NULL;
370         }
371
372         while (head->processing) {
373                 struct rb_node *node;
374
375                 node = rb_next(&head->href_node);
376                 if (!node) {
377                         if (loop)
378                                 return NULL;
379                         delayed_refs->run_delayed_start = 0;
380                         start = 0;
381                         loop = true;
382                         goto again;
383                 }
384                 head = rb_entry(node, struct btrfs_delayed_ref_head,
385                                 href_node);
386         }
387
388         head->processing = 1;
389         WARN_ON(delayed_refs->num_heads_ready == 0);
390         delayed_refs->num_heads_ready--;
391         delayed_refs->run_delayed_start = head->bytenr +
392                 head->num_bytes;
393         return head;
394 }
395
396 /*
397  * Helper to insert the ref_node to the tail or merge with tail.
398  *
399  * Return 0 for insert.
400  * Return >0 for merge.
401  */
402 static int insert_delayed_ref(struct btrfs_trans_handle *trans,
403                               struct btrfs_delayed_ref_root *root,
404                               struct btrfs_delayed_ref_head *href,
405                               struct btrfs_delayed_ref_node *ref)
406 {
407         struct btrfs_delayed_ref_node *exist;
408         int mod;
409         int ret = 0;
410
411         spin_lock(&href->lock);
412         exist = tree_insert(&href->ref_tree, ref);
413         if (!exist)
414                 goto inserted;
415
416         /* Now we are sure we can merge */
417         ret = 1;
418         if (exist->action == ref->action) {
419                 mod = ref->ref_mod;
420         } else {
421                 /* Need to change action */
422                 if (exist->ref_mod < ref->ref_mod) {
423                         exist->action = ref->action;
424                         mod = -exist->ref_mod;
425                         exist->ref_mod = ref->ref_mod;
426                         if (ref->action == BTRFS_ADD_DELAYED_REF)
427                                 list_add_tail(&exist->add_list,
428                                               &href->ref_add_list);
429                         else if (ref->action == BTRFS_DROP_DELAYED_REF) {
430                                 ASSERT(!list_empty(&exist->add_list));
431                                 list_del(&exist->add_list);
432                         } else {
433                                 ASSERT(0);
434                         }
435                 } else
436                         mod = -ref->ref_mod;
437         }
438         exist->ref_mod += mod;
439
440         /* remove existing tail if its ref_mod is zero */
441         if (exist->ref_mod == 0)
442                 drop_delayed_ref(trans, root, href, exist);
443         spin_unlock(&href->lock);
444         return ret;
445 inserted:
446         if (ref->action == BTRFS_ADD_DELAYED_REF)
447                 list_add_tail(&ref->add_list, &href->ref_add_list);
448         atomic_inc(&root->num_entries);
449         trans->delayed_ref_updates++;
450         spin_unlock(&href->lock);
451         return ret;
452 }
453
454 /*
455  * helper function to update the accounting in the head ref
456  * existing and update must have the same bytenr
457  */
458 static noinline void
459 update_existing_head_ref(struct btrfs_delayed_ref_root *delayed_refs,
460                          struct btrfs_delayed_ref_head *existing,
461                          struct btrfs_delayed_ref_head *update,
462                          int *old_ref_mod_ret)
463 {
464         int old_ref_mod;
465
466         BUG_ON(existing->is_data != update->is_data);
467
468         spin_lock(&existing->lock);
469         if (update->must_insert_reserved) {
470                 /* if the extent was freed and then
471                  * reallocated before the delayed ref
472                  * entries were processed, we can end up
473                  * with an existing head ref without
474                  * the must_insert_reserved flag set.
475                  * Set it again here
476                  */
477                 existing->must_insert_reserved = update->must_insert_reserved;
478
479                 /*
480                  * update the num_bytes so we make sure the accounting
481                  * is done correctly
482                  */
483                 existing->num_bytes = update->num_bytes;
484
485         }
486
487         if (update->extent_op) {
488                 if (!existing->extent_op) {
489                         existing->extent_op = update->extent_op;
490                 } else {
491                         if (update->extent_op->update_key) {
492                                 memcpy(&existing->extent_op->key,
493                                        &update->extent_op->key,
494                                        sizeof(update->extent_op->key));
495                                 existing->extent_op->update_key = true;
496                         }
497                         if (update->extent_op->update_flags) {
498                                 existing->extent_op->flags_to_set |=
499                                         update->extent_op->flags_to_set;
500                                 existing->extent_op->update_flags = true;
501                         }
502                         btrfs_free_delayed_extent_op(update->extent_op);
503                 }
504         }
505         /*
506          * update the reference mod on the head to reflect this new operation,
507          * only need the lock for this case cause we could be processing it
508          * currently, for refs we just added we know we're a-ok.
509          */
510         old_ref_mod = existing->total_ref_mod;
511         if (old_ref_mod_ret)
512                 *old_ref_mod_ret = old_ref_mod;
513         existing->ref_mod += update->ref_mod;
514         existing->total_ref_mod += update->ref_mod;
515
516         /*
517          * If we are going to from a positive ref mod to a negative or vice
518          * versa we need to make sure to adjust pending_csums accordingly.
519          */
520         if (existing->is_data) {
521                 if (existing->total_ref_mod >= 0 && old_ref_mod < 0)
522                         delayed_refs->pending_csums -= existing->num_bytes;
523                 if (existing->total_ref_mod < 0 && old_ref_mod >= 0)
524                         delayed_refs->pending_csums += existing->num_bytes;
525         }
526         spin_unlock(&existing->lock);
527 }
528
529 static void init_delayed_ref_head(struct btrfs_delayed_ref_head *head_ref,
530                                   struct btrfs_qgroup_extent_record *qrecord,
531                                   u64 bytenr, u64 num_bytes, u64 ref_root,
532                                   u64 reserved, int action, bool is_data,
533                                   bool is_system)
534 {
535         int count_mod = 1;
536         int must_insert_reserved = 0;
537
538         /* If reserved is provided, it must be a data extent. */
539         BUG_ON(!is_data && reserved);
540
541         /*
542          * The head node stores the sum of all the mods, so dropping a ref
543          * should drop the sum in the head node by one.
544          */
545         if (action == BTRFS_UPDATE_DELAYED_HEAD)
546                 count_mod = 0;
547         else if (action == BTRFS_DROP_DELAYED_REF)
548                 count_mod = -1;
549
550         /*
551          * BTRFS_ADD_DELAYED_EXTENT means that we need to update the reserved
552          * accounting when the extent is finally added, or if a later
553          * modification deletes the delayed ref without ever inserting the
554          * extent into the extent allocation tree.  ref->must_insert_reserved
555          * is the flag used to record that accounting mods are required.
556          *
557          * Once we record must_insert_reserved, switch the action to
558          * BTRFS_ADD_DELAYED_REF because other special casing is not required.
559          */
560         if (action == BTRFS_ADD_DELAYED_EXTENT)
561                 must_insert_reserved = 1;
562         else
563                 must_insert_reserved = 0;
564
565         refcount_set(&head_ref->refs, 1);
566         head_ref->bytenr = bytenr;
567         head_ref->num_bytes = num_bytes;
568         head_ref->ref_mod = count_mod;
569         head_ref->must_insert_reserved = must_insert_reserved;
570         head_ref->is_data = is_data;
571         head_ref->is_system = is_system;
572         head_ref->ref_tree = RB_ROOT;
573         INIT_LIST_HEAD(&head_ref->ref_add_list);
574         RB_CLEAR_NODE(&head_ref->href_node);
575         head_ref->processing = 0;
576         head_ref->total_ref_mod = count_mod;
577         head_ref->qgroup_reserved = 0;
578         head_ref->qgroup_ref_root = 0;
579         spin_lock_init(&head_ref->lock);
580         mutex_init(&head_ref->mutex);
581
582         if (qrecord) {
583                 if (ref_root && reserved) {
584                         head_ref->qgroup_ref_root = ref_root;
585                         head_ref->qgroup_reserved = reserved;
586                 }
587
588                 qrecord->bytenr = bytenr;
589                 qrecord->num_bytes = num_bytes;
590                 qrecord->old_roots = NULL;
591         }
592 }
593
594 /*
595  * helper function to actually insert a head node into the rbtree.
596  * this does all the dirty work in terms of maintaining the correct
597  * overall modification count.
598  */
599 static noinline struct btrfs_delayed_ref_head *
600 add_delayed_ref_head(struct btrfs_trans_handle *trans,
601                      struct btrfs_delayed_ref_head *head_ref,
602                      struct btrfs_qgroup_extent_record *qrecord,
603                      int action, int *qrecord_inserted_ret,
604                      int *old_ref_mod, int *new_ref_mod)
605 {
606         struct btrfs_delayed_ref_head *existing;
607         struct btrfs_delayed_ref_root *delayed_refs;
608         int qrecord_inserted = 0;
609
610         delayed_refs = &trans->transaction->delayed_refs;
611
612         /* Record qgroup extent info if provided */
613         if (qrecord) {
614                 if (btrfs_qgroup_trace_extent_nolock(trans->fs_info,
615                                         delayed_refs, qrecord))
616                         kfree(qrecord);
617                 else
618                         qrecord_inserted = 1;
619         }
620
621         trace_add_delayed_ref_head(trans->fs_info, head_ref, action);
622
623         existing = htree_insert(&delayed_refs->href_root,
624                                 &head_ref->href_node);
625         if (existing) {
626                 WARN_ON(qrecord && head_ref->qgroup_ref_root
627                         && head_ref->qgroup_reserved
628                         && existing->qgroup_ref_root
629                         && existing->qgroup_reserved);
630                 update_existing_head_ref(delayed_refs, existing, head_ref,
631                                          old_ref_mod);
632                 /*
633                  * we've updated the existing ref, free the newly
634                  * allocated ref
635                  */
636                 kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
637                 head_ref = existing;
638         } else {
639                 if (old_ref_mod)
640                         *old_ref_mod = 0;
641                 if (head_ref->is_data && head_ref->ref_mod < 0)
642                         delayed_refs->pending_csums += head_ref->num_bytes;
643                 delayed_refs->num_heads++;
644                 delayed_refs->num_heads_ready++;
645                 atomic_inc(&delayed_refs->num_entries);
646                 trans->delayed_ref_updates++;
647         }
648         if (qrecord_inserted_ret)
649                 *qrecord_inserted_ret = qrecord_inserted;
650         if (new_ref_mod)
651                 *new_ref_mod = head_ref->total_ref_mod;
652
653         return head_ref;
654 }
655
656 /*
657  * init_delayed_ref_common - Initialize the structure which represents a
658  *                           modification to a an extent.
659  *
660  * @fs_info:    Internal to the mounted filesystem mount structure.
661  *
662  * @ref:        The structure which is going to be initialized.
663  *
664  * @bytenr:     The logical address of the extent for which a modification is
665  *              going to be recorded.
666  *
667  * @num_bytes:  Size of the extent whose modification is being recorded.
668  *
669  * @ref_root:   The id of the root where this modification has originated, this
670  *              can be either one of the well-known metadata trees or the
671  *              subvolume id which references this extent.
672  *
673  * @action:     Can be one of BTRFS_ADD_DELAYED_REF/BTRFS_DROP_DELAYED_REF or
674  *              BTRFS_ADD_DELAYED_EXTENT
675  *
676  * @ref_type:   Holds the type of the extent which is being recorded, can be
677  *              one of BTRFS_SHARED_BLOCK_REF_KEY/BTRFS_TREE_BLOCK_REF_KEY
678  *              when recording a metadata extent or BTRFS_SHARED_DATA_REF_KEY/
679  *              BTRFS_EXTENT_DATA_REF_KEY when recording data extent
680  */
681 static void init_delayed_ref_common(struct btrfs_fs_info *fs_info,
682                                     struct btrfs_delayed_ref_node *ref,
683                                     u64 bytenr, u64 num_bytes, u64 ref_root,
684                                     int action, u8 ref_type)
685 {
686         u64 seq = 0;
687
688         if (action == BTRFS_ADD_DELAYED_EXTENT)
689                 action = BTRFS_ADD_DELAYED_REF;
690
691         if (is_fstree(ref_root))
692                 seq = atomic64_read(&fs_info->tree_mod_seq);
693
694         refcount_set(&ref->refs, 1);
695         ref->bytenr = bytenr;
696         ref->num_bytes = num_bytes;
697         ref->ref_mod = 1;
698         ref->action = action;
699         ref->is_head = 0;
700         ref->in_tree = 1;
701         ref->seq = seq;
702         ref->type = ref_type;
703         RB_CLEAR_NODE(&ref->ref_node);
704         INIT_LIST_HEAD(&ref->add_list);
705 }
706
707 /*
708  * add a delayed tree ref.  This does all of the accounting required
709  * to make sure the delayed ref is eventually processed before this
710  * transaction commits.
711  */
712 int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans,
713                                u64 bytenr, u64 num_bytes, u64 parent,
714                                u64 ref_root,  int level, int action,
715                                struct btrfs_delayed_extent_op *extent_op,
716                                int *old_ref_mod, int *new_ref_mod)
717 {
718         struct btrfs_fs_info *fs_info = trans->fs_info;
719         struct btrfs_delayed_tree_ref *ref;
720         struct btrfs_delayed_ref_head *head_ref;
721         struct btrfs_delayed_ref_root *delayed_refs;
722         struct btrfs_qgroup_extent_record *record = NULL;
723         int qrecord_inserted;
724         bool is_system = (ref_root == BTRFS_CHUNK_TREE_OBJECTID);
725         int ret;
726         u8 ref_type;
727
728         BUG_ON(extent_op && extent_op->is_data);
729         ref = kmem_cache_alloc(btrfs_delayed_tree_ref_cachep, GFP_NOFS);
730         if (!ref)
731                 return -ENOMEM;
732
733         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
734         if (!head_ref) {
735                 kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
736                 return -ENOMEM;
737         }
738
739         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) &&
740             is_fstree(ref_root)) {
741                 record = kmalloc(sizeof(*record), GFP_NOFS);
742                 if (!record) {
743                         kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
744                         kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
745                         return -ENOMEM;
746                 }
747         }
748
749         if (parent)
750                 ref_type = BTRFS_SHARED_BLOCK_REF_KEY;
751         else
752                 ref_type = BTRFS_TREE_BLOCK_REF_KEY;
753
754         init_delayed_ref_common(fs_info, &ref->node, bytenr, num_bytes,
755                                 ref_root, action, ref_type);
756         ref->root = ref_root;
757         ref->parent = parent;
758         ref->level = level;
759
760         init_delayed_ref_head(head_ref, record, bytenr, num_bytes,
761                               ref_root, 0, action, false, is_system);
762         head_ref->extent_op = extent_op;
763
764         delayed_refs = &trans->transaction->delayed_refs;
765         spin_lock(&delayed_refs->lock);
766
767         /*
768          * insert both the head node and the new ref without dropping
769          * the spin lock
770          */
771         head_ref = add_delayed_ref_head(trans, head_ref, record,
772                                         action, &qrecord_inserted,
773                                         old_ref_mod, new_ref_mod);
774
775         ret = insert_delayed_ref(trans, delayed_refs, head_ref, &ref->node);
776         spin_unlock(&delayed_refs->lock);
777
778         trace_add_delayed_tree_ref(fs_info, &ref->node, ref,
779                                    action == BTRFS_ADD_DELAYED_EXTENT ?
780                                    BTRFS_ADD_DELAYED_REF : action);
781         if (ret > 0)
782                 kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
783
784         if (qrecord_inserted)
785                 btrfs_qgroup_trace_extent_post(fs_info, record);
786
787         return 0;
788 }
789
790 /*
791  * add a delayed data ref. it's similar to btrfs_add_delayed_tree_ref.
792  */
793 int btrfs_add_delayed_data_ref(struct btrfs_trans_handle *trans,
794                                u64 bytenr, u64 num_bytes,
795                                u64 parent, u64 ref_root,
796                                u64 owner, u64 offset, u64 reserved, int action,
797                                int *old_ref_mod, int *new_ref_mod)
798 {
799         struct btrfs_fs_info *fs_info = trans->fs_info;
800         struct btrfs_delayed_data_ref *ref;
801         struct btrfs_delayed_ref_head *head_ref;
802         struct btrfs_delayed_ref_root *delayed_refs;
803         struct btrfs_qgroup_extent_record *record = NULL;
804         int qrecord_inserted;
805         int ret;
806         u8 ref_type;
807
808         ref = kmem_cache_alloc(btrfs_delayed_data_ref_cachep, GFP_NOFS);
809         if (!ref)
810                 return -ENOMEM;
811
812         if (parent)
813                 ref_type = BTRFS_SHARED_DATA_REF_KEY;
814         else
815                 ref_type = BTRFS_EXTENT_DATA_REF_KEY;
816         init_delayed_ref_common(fs_info, &ref->node, bytenr, num_bytes,
817                                 ref_root, action, ref_type);
818         ref->root = ref_root;
819         ref->parent = parent;
820         ref->objectid = owner;
821         ref->offset = offset;
822
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         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) &&
831             is_fstree(ref_root)) {
832                 record = kmalloc(sizeof(*record), GFP_NOFS);
833                 if (!record) {
834                         kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
835                         kmem_cache_free(btrfs_delayed_ref_head_cachep,
836                                         head_ref);
837                         return -ENOMEM;
838                 }
839         }
840
841         init_delayed_ref_head(head_ref, record, bytenr, num_bytes, ref_root,
842                               reserved, action, true, false);
843         head_ref->extent_op = NULL;
844
845         delayed_refs = &trans->transaction->delayed_refs;
846         spin_lock(&delayed_refs->lock);
847
848         /*
849          * insert both the head node and the new ref without dropping
850          * the spin lock
851          */
852         head_ref = add_delayed_ref_head(trans, head_ref, record,
853                                         action, &qrecord_inserted,
854                                         old_ref_mod, new_ref_mod);
855
856         ret = insert_delayed_ref(trans, delayed_refs, head_ref, &ref->node);
857         spin_unlock(&delayed_refs->lock);
858
859         trace_add_delayed_data_ref(trans->fs_info, &ref->node, ref,
860                                    action == BTRFS_ADD_DELAYED_EXTENT ?
861                                    BTRFS_ADD_DELAYED_REF : action);
862         if (ret > 0)
863                 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
864
865
866         if (qrecord_inserted)
867                 return btrfs_qgroup_trace_extent_post(fs_info, record);
868         return 0;
869 }
870
871 int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
872                                 struct btrfs_trans_handle *trans,
873                                 u64 bytenr, u64 num_bytes,
874                                 struct btrfs_delayed_extent_op *extent_op)
875 {
876         struct btrfs_delayed_ref_head *head_ref;
877         struct btrfs_delayed_ref_root *delayed_refs;
878
879         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
880         if (!head_ref)
881                 return -ENOMEM;
882
883         init_delayed_ref_head(head_ref, NULL, bytenr, num_bytes, 0, 0,
884                               BTRFS_UPDATE_DELAYED_HEAD, extent_op->is_data,
885                               false);
886         head_ref->extent_op = extent_op;
887
888         delayed_refs = &trans->transaction->delayed_refs;
889         spin_lock(&delayed_refs->lock);
890
891         add_delayed_ref_head(trans, head_ref, NULL, BTRFS_UPDATE_DELAYED_HEAD,
892                              NULL, NULL, NULL);
893
894         spin_unlock(&delayed_refs->lock);
895         return 0;
896 }
897
898 /*
899  * this does a simple search for the head node for a given extent.
900  * It must be called with the delayed ref spinlock held, and it returns
901  * the head node if any where found, or NULL if not.
902  */
903 struct btrfs_delayed_ref_head *
904 btrfs_find_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs, u64 bytenr)
905 {
906         return find_ref_head(&delayed_refs->href_root, bytenr, 0);
907 }
908
909 void __cold btrfs_delayed_ref_exit(void)
910 {
911         kmem_cache_destroy(btrfs_delayed_ref_head_cachep);
912         kmem_cache_destroy(btrfs_delayed_tree_ref_cachep);
913         kmem_cache_destroy(btrfs_delayed_data_ref_cachep);
914         kmem_cache_destroy(btrfs_delayed_extent_op_cachep);
915 }
916
917 int __init btrfs_delayed_ref_init(void)
918 {
919         btrfs_delayed_ref_head_cachep = kmem_cache_create(
920                                 "btrfs_delayed_ref_head",
921                                 sizeof(struct btrfs_delayed_ref_head), 0,
922                                 SLAB_MEM_SPREAD, NULL);
923         if (!btrfs_delayed_ref_head_cachep)
924                 goto fail;
925
926         btrfs_delayed_tree_ref_cachep = kmem_cache_create(
927                                 "btrfs_delayed_tree_ref",
928                                 sizeof(struct btrfs_delayed_tree_ref), 0,
929                                 SLAB_MEM_SPREAD, NULL);
930         if (!btrfs_delayed_tree_ref_cachep)
931                 goto fail;
932
933         btrfs_delayed_data_ref_cachep = kmem_cache_create(
934                                 "btrfs_delayed_data_ref",
935                                 sizeof(struct btrfs_delayed_data_ref), 0,
936                                 SLAB_MEM_SPREAD, NULL);
937         if (!btrfs_delayed_data_ref_cachep)
938                 goto fail;
939
940         btrfs_delayed_extent_op_cachep = kmem_cache_create(
941                                 "btrfs_delayed_extent_op",
942                                 sizeof(struct btrfs_delayed_extent_op), 0,
943                                 SLAB_MEM_SPREAD, NULL);
944         if (!btrfs_delayed_extent_op_cachep)
945                 goto fail;
946
947         return 0;
948 fail:
949         btrfs_delayed_ref_exit();
950         return -ENOMEM;
951 }