GNU Linux-libre 4.19.211-gnu1
[releases.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 }
238
239 static bool merge_ref(struct btrfs_trans_handle *trans,
240                       struct btrfs_delayed_ref_root *delayed_refs,
241                       struct btrfs_delayed_ref_head *head,
242                       struct btrfs_delayed_ref_node *ref,
243                       u64 seq)
244 {
245         struct btrfs_delayed_ref_node *next;
246         struct rb_node *node = rb_next(&ref->ref_node);
247         bool done = false;
248
249         while (!done && node) {
250                 int mod;
251
252                 next = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
253                 node = rb_next(node);
254                 if (seq && next->seq >= seq)
255                         break;
256                 if (comp_refs(ref, next, false))
257                         break;
258
259                 if (ref->action == next->action) {
260                         mod = next->ref_mod;
261                 } else {
262                         if (ref->ref_mod < next->ref_mod) {
263                                 swap(ref, next);
264                                 done = true;
265                         }
266                         mod = -next->ref_mod;
267                 }
268
269                 drop_delayed_ref(trans, delayed_refs, head, next);
270                 ref->ref_mod += mod;
271                 if (ref->ref_mod == 0) {
272                         drop_delayed_ref(trans, delayed_refs, head, ref);
273                         done = true;
274                 } else {
275                         /*
276                          * Can't have multiples of the same ref on a tree block.
277                          */
278                         WARN_ON(ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
279                                 ref->type == BTRFS_SHARED_BLOCK_REF_KEY);
280                 }
281         }
282
283         return done;
284 }
285
286 void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
287                               struct btrfs_delayed_ref_root *delayed_refs,
288                               struct btrfs_delayed_ref_head *head)
289 {
290         struct btrfs_fs_info *fs_info = trans->fs_info;
291         struct btrfs_delayed_ref_node *ref;
292         struct rb_node *node;
293         u64 seq = 0;
294
295         lockdep_assert_held(&head->lock);
296
297         if (RB_EMPTY_ROOT(&head->ref_tree))
298                 return;
299
300         /* We don't have too many refs to merge for data. */
301         if (head->is_data)
302                 return;
303
304         read_lock(&fs_info->tree_mod_log_lock);
305         if (!list_empty(&fs_info->tree_mod_seq_list)) {
306                 struct seq_list *elem;
307
308                 elem = list_first_entry(&fs_info->tree_mod_seq_list,
309                                         struct seq_list, list);
310                 seq = elem->seq;
311         }
312         read_unlock(&fs_info->tree_mod_log_lock);
313
314 again:
315         for (node = rb_first(&head->ref_tree); node; node = rb_next(node)) {
316                 ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
317                 if (seq && ref->seq >= seq)
318                         continue;
319                 if (merge_ref(trans, delayed_refs, head, ref, seq))
320                         goto again;
321         }
322 }
323
324 int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info, u64 seq)
325 {
326         struct seq_list *elem;
327         int ret = 0;
328
329         read_lock(&fs_info->tree_mod_log_lock);
330         if (!list_empty(&fs_info->tree_mod_seq_list)) {
331                 elem = list_first_entry(&fs_info->tree_mod_seq_list,
332                                         struct seq_list, list);
333                 if (seq >= elem->seq) {
334                         btrfs_debug(fs_info,
335                                 "holding back delayed_ref %#x.%x, lowest is %#x.%x",
336                                 (u32)(seq >> 32), (u32)seq,
337                                 (u32)(elem->seq >> 32), (u32)elem->seq);
338                         ret = 1;
339                 }
340         }
341
342         read_unlock(&fs_info->tree_mod_log_lock);
343         return ret;
344 }
345
346 struct btrfs_delayed_ref_head *
347 btrfs_select_ref_head(struct btrfs_trans_handle *trans)
348 {
349         struct btrfs_delayed_ref_root *delayed_refs;
350         struct btrfs_delayed_ref_head *head;
351         u64 start;
352         bool loop = false;
353
354         delayed_refs = &trans->transaction->delayed_refs;
355
356 again:
357         start = delayed_refs->run_delayed_start;
358         head = find_ref_head(&delayed_refs->href_root, start, 1);
359         if (!head && !loop) {
360                 delayed_refs->run_delayed_start = 0;
361                 start = 0;
362                 loop = true;
363                 head = find_ref_head(&delayed_refs->href_root, start, 1);
364                 if (!head)
365                         return NULL;
366         } else if (!head && loop) {
367                 return NULL;
368         }
369
370         while (head->processing) {
371                 struct rb_node *node;
372
373                 node = rb_next(&head->href_node);
374                 if (!node) {
375                         if (loop)
376                                 return NULL;
377                         delayed_refs->run_delayed_start = 0;
378                         start = 0;
379                         loop = true;
380                         goto again;
381                 }
382                 head = rb_entry(node, struct btrfs_delayed_ref_head,
383                                 href_node);
384         }
385
386         head->processing = 1;
387         WARN_ON(delayed_refs->num_heads_ready == 0);
388         delayed_refs->num_heads_ready--;
389         delayed_refs->run_delayed_start = head->bytenr +
390                 head->num_bytes;
391         return head;
392 }
393
394 /*
395  * Helper to insert the ref_node to the tail or merge with tail.
396  *
397  * Return 0 for insert.
398  * Return >0 for merge.
399  */
400 static int insert_delayed_ref(struct btrfs_trans_handle *trans,
401                               struct btrfs_delayed_ref_root *root,
402                               struct btrfs_delayed_ref_head *href,
403                               struct btrfs_delayed_ref_node *ref)
404 {
405         struct btrfs_delayed_ref_node *exist;
406         int mod;
407         int ret = 0;
408
409         spin_lock(&href->lock);
410         exist = tree_insert(&href->ref_tree, ref);
411         if (!exist)
412                 goto inserted;
413
414         /* Now we are sure we can merge */
415         ret = 1;
416         if (exist->action == ref->action) {
417                 mod = ref->ref_mod;
418         } else {
419                 /* Need to change action */
420                 if (exist->ref_mod < ref->ref_mod) {
421                         exist->action = ref->action;
422                         mod = -exist->ref_mod;
423                         exist->ref_mod = ref->ref_mod;
424                         if (ref->action == BTRFS_ADD_DELAYED_REF)
425                                 list_add_tail(&exist->add_list,
426                                               &href->ref_add_list);
427                         else if (ref->action == BTRFS_DROP_DELAYED_REF) {
428                                 ASSERT(!list_empty(&exist->add_list));
429                                 list_del(&exist->add_list);
430                         } else {
431                                 ASSERT(0);
432                         }
433                 } else
434                         mod = -ref->ref_mod;
435         }
436         exist->ref_mod += mod;
437
438         /* remove existing tail if its ref_mod is zero */
439         if (exist->ref_mod == 0)
440                 drop_delayed_ref(trans, root, href, exist);
441         spin_unlock(&href->lock);
442         return ret;
443 inserted:
444         if (ref->action == BTRFS_ADD_DELAYED_REF)
445                 list_add_tail(&ref->add_list, &href->ref_add_list);
446         atomic_inc(&root->num_entries);
447         spin_unlock(&href->lock);
448         return ret;
449 }
450
451 /*
452  * helper function to update the accounting in the head ref
453  * existing and update must have the same bytenr
454  */
455 static noinline void
456 update_existing_head_ref(struct btrfs_delayed_ref_root *delayed_refs,
457                          struct btrfs_delayed_ref_head *existing,
458                          struct btrfs_delayed_ref_head *update,
459                          int *old_ref_mod_ret)
460 {
461         int old_ref_mod;
462
463         BUG_ON(existing->is_data != update->is_data);
464
465         spin_lock(&existing->lock);
466         if (update->must_insert_reserved) {
467                 /* if the extent was freed and then
468                  * reallocated before the delayed ref
469                  * entries were processed, we can end up
470                  * with an existing head ref without
471                  * the must_insert_reserved flag set.
472                  * Set it again here
473                  */
474                 existing->must_insert_reserved = update->must_insert_reserved;
475
476                 /*
477                  * update the num_bytes so we make sure the accounting
478                  * is done correctly
479                  */
480                 existing->num_bytes = update->num_bytes;
481
482         }
483
484         if (update->extent_op) {
485                 if (!existing->extent_op) {
486                         existing->extent_op = update->extent_op;
487                 } else {
488                         if (update->extent_op->update_key) {
489                                 memcpy(&existing->extent_op->key,
490                                        &update->extent_op->key,
491                                        sizeof(update->extent_op->key));
492                                 existing->extent_op->update_key = true;
493                         }
494                         if (update->extent_op->update_flags) {
495                                 existing->extent_op->flags_to_set |=
496                                         update->extent_op->flags_to_set;
497                                 existing->extent_op->update_flags = true;
498                         }
499                         btrfs_free_delayed_extent_op(update->extent_op);
500                 }
501         }
502         /*
503          * update the reference mod on the head to reflect this new operation,
504          * only need the lock for this case cause we could be processing it
505          * currently, for refs we just added we know we're a-ok.
506          */
507         old_ref_mod = existing->total_ref_mod;
508         if (old_ref_mod_ret)
509                 *old_ref_mod_ret = old_ref_mod;
510         existing->ref_mod += update->ref_mod;
511         existing->total_ref_mod += update->ref_mod;
512
513         /*
514          * If we are going to from a positive ref mod to a negative or vice
515          * versa we need to make sure to adjust pending_csums accordingly.
516          */
517         if (existing->is_data) {
518                 if (existing->total_ref_mod >= 0 && old_ref_mod < 0)
519                         delayed_refs->pending_csums -= existing->num_bytes;
520                 if (existing->total_ref_mod < 0 && old_ref_mod >= 0)
521                         delayed_refs->pending_csums += existing->num_bytes;
522         }
523         spin_unlock(&existing->lock);
524 }
525
526 static void init_delayed_ref_head(struct btrfs_delayed_ref_head *head_ref,
527                                   struct btrfs_qgroup_extent_record *qrecord,
528                                   u64 bytenr, u64 num_bytes, u64 ref_root,
529                                   u64 reserved, int action, bool is_data,
530                                   bool is_system)
531 {
532         int count_mod = 1;
533         int must_insert_reserved = 0;
534
535         /* If reserved is provided, it must be a data extent. */
536         BUG_ON(!is_data && reserved);
537
538         /*
539          * The head node stores the sum of all the mods, so dropping a ref
540          * should drop the sum in the head node by one.
541          */
542         if (action == BTRFS_UPDATE_DELAYED_HEAD)
543                 count_mod = 0;
544         else if (action == BTRFS_DROP_DELAYED_REF)
545                 count_mod = -1;
546
547         /*
548          * BTRFS_ADD_DELAYED_EXTENT means that we need to update the reserved
549          * accounting when the extent is finally added, or if a later
550          * modification deletes the delayed ref without ever inserting the
551          * extent into the extent allocation tree.  ref->must_insert_reserved
552          * is the flag used to record that accounting mods are required.
553          *
554          * Once we record must_insert_reserved, switch the action to
555          * BTRFS_ADD_DELAYED_REF because other special casing is not required.
556          */
557         if (action == BTRFS_ADD_DELAYED_EXTENT)
558                 must_insert_reserved = 1;
559         else
560                 must_insert_reserved = 0;
561
562         refcount_set(&head_ref->refs, 1);
563         head_ref->bytenr = bytenr;
564         head_ref->num_bytes = num_bytes;
565         head_ref->ref_mod = count_mod;
566         head_ref->must_insert_reserved = must_insert_reserved;
567         head_ref->is_data = is_data;
568         head_ref->is_system = is_system;
569         head_ref->ref_tree = RB_ROOT;
570         INIT_LIST_HEAD(&head_ref->ref_add_list);
571         RB_CLEAR_NODE(&head_ref->href_node);
572         head_ref->processing = 0;
573         head_ref->total_ref_mod = count_mod;
574         head_ref->qgroup_reserved = 0;
575         head_ref->qgroup_ref_root = 0;
576         spin_lock_init(&head_ref->lock);
577         mutex_init(&head_ref->mutex);
578
579         if (qrecord) {
580                 if (ref_root && reserved) {
581                         head_ref->qgroup_ref_root = ref_root;
582                         head_ref->qgroup_reserved = reserved;
583                 }
584
585                 qrecord->bytenr = bytenr;
586                 qrecord->num_bytes = num_bytes;
587                 qrecord->old_roots = NULL;
588         }
589 }
590
591 /*
592  * helper function to actually insert a head node into the rbtree.
593  * this does all the dirty work in terms of maintaining the correct
594  * overall modification count.
595  */
596 static noinline struct btrfs_delayed_ref_head *
597 add_delayed_ref_head(struct btrfs_trans_handle *trans,
598                      struct btrfs_delayed_ref_head *head_ref,
599                      struct btrfs_qgroup_extent_record *qrecord,
600                      int action, int *qrecord_inserted_ret,
601                      int *old_ref_mod, int *new_ref_mod)
602 {
603         struct btrfs_delayed_ref_head *existing;
604         struct btrfs_delayed_ref_root *delayed_refs;
605         int qrecord_inserted = 0;
606
607         delayed_refs = &trans->transaction->delayed_refs;
608
609         /* Record qgroup extent info if provided */
610         if (qrecord) {
611                 if (btrfs_qgroup_trace_extent_nolock(trans->fs_info,
612                                         delayed_refs, qrecord))
613                         kfree(qrecord);
614                 else
615                         qrecord_inserted = 1;
616         }
617
618         trace_add_delayed_ref_head(trans->fs_info, head_ref, action);
619
620         existing = htree_insert(&delayed_refs->href_root,
621                                 &head_ref->href_node);
622         if (existing) {
623                 WARN_ON(qrecord && head_ref->qgroup_ref_root
624                         && head_ref->qgroup_reserved
625                         && existing->qgroup_ref_root
626                         && existing->qgroup_reserved);
627                 update_existing_head_ref(delayed_refs, existing, head_ref,
628                                          old_ref_mod);
629                 /*
630                  * we've updated the existing ref, free the newly
631                  * allocated ref
632                  */
633                 kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
634                 head_ref = existing;
635         } else {
636                 if (old_ref_mod)
637                         *old_ref_mod = 0;
638                 if (head_ref->is_data && head_ref->ref_mod < 0)
639                         delayed_refs->pending_csums += head_ref->num_bytes;
640                 delayed_refs->num_heads++;
641                 delayed_refs->num_heads_ready++;
642                 atomic_inc(&delayed_refs->num_entries);
643                 trans->delayed_ref_updates++;
644         }
645         if (qrecord_inserted_ret)
646                 *qrecord_inserted_ret = qrecord_inserted;
647         if (new_ref_mod)
648                 *new_ref_mod = head_ref->total_ref_mod;
649
650         return head_ref;
651 }
652
653 /*
654  * init_delayed_ref_common - Initialize the structure which represents a
655  *                           modification to a an extent.
656  *
657  * @fs_info:    Internal to the mounted filesystem mount structure.
658  *
659  * @ref:        The structure which is going to be initialized.
660  *
661  * @bytenr:     The logical address of the extent for which a modification is
662  *              going to be recorded.
663  *
664  * @num_bytes:  Size of the extent whose modification is being recorded.
665  *
666  * @ref_root:   The id of the root where this modification has originated, this
667  *              can be either one of the well-known metadata trees or the
668  *              subvolume id which references this extent.
669  *
670  * @action:     Can be one of BTRFS_ADD_DELAYED_REF/BTRFS_DROP_DELAYED_REF or
671  *              BTRFS_ADD_DELAYED_EXTENT
672  *
673  * @ref_type:   Holds the type of the extent which is being recorded, can be
674  *              one of BTRFS_SHARED_BLOCK_REF_KEY/BTRFS_TREE_BLOCK_REF_KEY
675  *              when recording a metadata extent or BTRFS_SHARED_DATA_REF_KEY/
676  *              BTRFS_EXTENT_DATA_REF_KEY when recording data extent
677  */
678 static void init_delayed_ref_common(struct btrfs_fs_info *fs_info,
679                                     struct btrfs_delayed_ref_node *ref,
680                                     u64 bytenr, u64 num_bytes, u64 ref_root,
681                                     int action, u8 ref_type)
682 {
683         u64 seq = 0;
684
685         if (action == BTRFS_ADD_DELAYED_EXTENT)
686                 action = BTRFS_ADD_DELAYED_REF;
687
688         if (is_fstree(ref_root))
689                 seq = atomic64_read(&fs_info->tree_mod_seq);
690
691         refcount_set(&ref->refs, 1);
692         ref->bytenr = bytenr;
693         ref->num_bytes = num_bytes;
694         ref->ref_mod = 1;
695         ref->action = action;
696         ref->is_head = 0;
697         ref->in_tree = 1;
698         ref->seq = seq;
699         ref->type = ref_type;
700         RB_CLEAR_NODE(&ref->ref_node);
701         INIT_LIST_HEAD(&ref->add_list);
702 }
703
704 /*
705  * add a delayed tree ref.  This does all of the accounting required
706  * to make sure the delayed ref is eventually processed before this
707  * transaction commits.
708  */
709 int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans,
710                                u64 bytenr, u64 num_bytes, u64 parent,
711                                u64 ref_root,  int level, int action,
712                                struct btrfs_delayed_extent_op *extent_op,
713                                int *old_ref_mod, int *new_ref_mod)
714 {
715         struct btrfs_fs_info *fs_info = trans->fs_info;
716         struct btrfs_delayed_tree_ref *ref;
717         struct btrfs_delayed_ref_head *head_ref;
718         struct btrfs_delayed_ref_root *delayed_refs;
719         struct btrfs_qgroup_extent_record *record = NULL;
720         int qrecord_inserted;
721         bool is_system = (ref_root == BTRFS_CHUNK_TREE_OBJECTID);
722         int ret;
723         u8 ref_type;
724
725         BUG_ON(extent_op && extent_op->is_data);
726         ref = kmem_cache_alloc(btrfs_delayed_tree_ref_cachep, GFP_NOFS);
727         if (!ref)
728                 return -ENOMEM;
729
730         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
731         if (!head_ref) {
732                 kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
733                 return -ENOMEM;
734         }
735
736         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) &&
737             is_fstree(ref_root)) {
738                 record = kmalloc(sizeof(*record), GFP_NOFS);
739                 if (!record) {
740                         kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
741                         kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
742                         return -ENOMEM;
743                 }
744         }
745
746         if (parent)
747                 ref_type = BTRFS_SHARED_BLOCK_REF_KEY;
748         else
749                 ref_type = BTRFS_TREE_BLOCK_REF_KEY;
750
751         init_delayed_ref_common(fs_info, &ref->node, bytenr, num_bytes,
752                                 ref_root, action, ref_type);
753         ref->root = ref_root;
754         ref->parent = parent;
755         ref->level = level;
756
757         init_delayed_ref_head(head_ref, record, bytenr, num_bytes,
758                               ref_root, 0, action, false, is_system);
759         head_ref->extent_op = extent_op;
760
761         delayed_refs = &trans->transaction->delayed_refs;
762         spin_lock(&delayed_refs->lock);
763
764         /*
765          * insert both the head node and the new ref without dropping
766          * the spin lock
767          */
768         head_ref = add_delayed_ref_head(trans, head_ref, record,
769                                         action, &qrecord_inserted,
770                                         old_ref_mod, new_ref_mod);
771
772         ret = insert_delayed_ref(trans, delayed_refs, head_ref, &ref->node);
773         spin_unlock(&delayed_refs->lock);
774
775         trace_add_delayed_tree_ref(fs_info, &ref->node, ref,
776                                    action == BTRFS_ADD_DELAYED_EXTENT ?
777                                    BTRFS_ADD_DELAYED_REF : action);
778         if (ret > 0)
779                 kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
780
781         if (qrecord_inserted)
782                 btrfs_qgroup_trace_extent_post(fs_info, record);
783
784         return 0;
785 }
786
787 /*
788  * add a delayed data ref. it's similar to btrfs_add_delayed_tree_ref.
789  */
790 int btrfs_add_delayed_data_ref(struct btrfs_trans_handle *trans,
791                                u64 bytenr, u64 num_bytes,
792                                u64 parent, u64 ref_root,
793                                u64 owner, u64 offset, u64 reserved, int action,
794                                int *old_ref_mod, int *new_ref_mod)
795 {
796         struct btrfs_fs_info *fs_info = trans->fs_info;
797         struct btrfs_delayed_data_ref *ref;
798         struct btrfs_delayed_ref_head *head_ref;
799         struct btrfs_delayed_ref_root *delayed_refs;
800         struct btrfs_qgroup_extent_record *record = NULL;
801         int qrecord_inserted;
802         int ret;
803         u8 ref_type;
804
805         ref = kmem_cache_alloc(btrfs_delayed_data_ref_cachep, GFP_NOFS);
806         if (!ref)
807                 return -ENOMEM;
808
809         if (parent)
810                 ref_type = BTRFS_SHARED_DATA_REF_KEY;
811         else
812                 ref_type = BTRFS_EXTENT_DATA_REF_KEY;
813         init_delayed_ref_common(fs_info, &ref->node, bytenr, num_bytes,
814                                 ref_root, action, ref_type);
815         ref->root = ref_root;
816         ref->parent = parent;
817         ref->objectid = owner;
818         ref->offset = offset;
819
820
821         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
822         if (!head_ref) {
823                 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
824                 return -ENOMEM;
825         }
826
827         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) &&
828             is_fstree(ref_root)) {
829                 record = kmalloc(sizeof(*record), GFP_NOFS);
830                 if (!record) {
831                         kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
832                         kmem_cache_free(btrfs_delayed_ref_head_cachep,
833                                         head_ref);
834                         return -ENOMEM;
835                 }
836         }
837
838         init_delayed_ref_head(head_ref, record, bytenr, num_bytes, ref_root,
839                               reserved, action, true, false);
840         head_ref->extent_op = NULL;
841
842         delayed_refs = &trans->transaction->delayed_refs;
843         spin_lock(&delayed_refs->lock);
844
845         /*
846          * insert both the head node and the new ref without dropping
847          * the spin lock
848          */
849         head_ref = add_delayed_ref_head(trans, head_ref, record,
850                                         action, &qrecord_inserted,
851                                         old_ref_mod, new_ref_mod);
852
853         ret = insert_delayed_ref(trans, delayed_refs, head_ref, &ref->node);
854         spin_unlock(&delayed_refs->lock);
855
856         trace_add_delayed_data_ref(trans->fs_info, &ref->node, ref,
857                                    action == BTRFS_ADD_DELAYED_EXTENT ?
858                                    BTRFS_ADD_DELAYED_REF : action);
859         if (ret > 0)
860                 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
861
862
863         if (qrecord_inserted)
864                 return btrfs_qgroup_trace_extent_post(fs_info, record);
865         return 0;
866 }
867
868 int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
869                                 struct btrfs_trans_handle *trans,
870                                 u64 bytenr, u64 num_bytes,
871                                 struct btrfs_delayed_extent_op *extent_op)
872 {
873         struct btrfs_delayed_ref_head *head_ref;
874         struct btrfs_delayed_ref_root *delayed_refs;
875
876         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
877         if (!head_ref)
878                 return -ENOMEM;
879
880         init_delayed_ref_head(head_ref, NULL, bytenr, num_bytes, 0, 0,
881                               BTRFS_UPDATE_DELAYED_HEAD, extent_op->is_data,
882                               false);
883         head_ref->extent_op = extent_op;
884
885         delayed_refs = &trans->transaction->delayed_refs;
886         spin_lock(&delayed_refs->lock);
887
888         add_delayed_ref_head(trans, head_ref, NULL, BTRFS_UPDATE_DELAYED_HEAD,
889                              NULL, NULL, NULL);
890
891         spin_unlock(&delayed_refs->lock);
892         return 0;
893 }
894
895 /*
896  * this does a simple search for the head node for a given extent.
897  * It must be called with the delayed ref spinlock held, and it returns
898  * the head node if any where found, or NULL if not.
899  */
900 struct btrfs_delayed_ref_head *
901 btrfs_find_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs, u64 bytenr)
902 {
903         return find_ref_head(&delayed_refs->href_root, bytenr, 0);
904 }
905
906 void __cold btrfs_delayed_ref_exit(void)
907 {
908         kmem_cache_destroy(btrfs_delayed_ref_head_cachep);
909         kmem_cache_destroy(btrfs_delayed_tree_ref_cachep);
910         kmem_cache_destroy(btrfs_delayed_data_ref_cachep);
911         kmem_cache_destroy(btrfs_delayed_extent_op_cachep);
912 }
913
914 int __init btrfs_delayed_ref_init(void)
915 {
916         btrfs_delayed_ref_head_cachep = kmem_cache_create(
917                                 "btrfs_delayed_ref_head",
918                                 sizeof(struct btrfs_delayed_ref_head), 0,
919                                 SLAB_MEM_SPREAD, NULL);
920         if (!btrfs_delayed_ref_head_cachep)
921                 goto fail;
922
923         btrfs_delayed_tree_ref_cachep = kmem_cache_create(
924                                 "btrfs_delayed_tree_ref",
925                                 sizeof(struct btrfs_delayed_tree_ref), 0,
926                                 SLAB_MEM_SPREAD, NULL);
927         if (!btrfs_delayed_tree_ref_cachep)
928                 goto fail;
929
930         btrfs_delayed_data_ref_cachep = kmem_cache_create(
931                                 "btrfs_delayed_data_ref",
932                                 sizeof(struct btrfs_delayed_data_ref), 0,
933                                 SLAB_MEM_SPREAD, NULL);
934         if (!btrfs_delayed_data_ref_cachep)
935                 goto fail;
936
937         btrfs_delayed_extent_op_cachep = kmem_cache_create(
938                                 "btrfs_delayed_extent_op",
939                                 sizeof(struct btrfs_delayed_extent_op), 0,
940                                 SLAB_MEM_SPREAD, NULL);
941         if (!btrfs_delayed_extent_op_cachep)
942                 goto fail;
943
944         return 0;
945 fail:
946         btrfs_delayed_ref_exit();
947         return -ENOMEM;
948 }