2 * Copyright (C) 2011 STRATO. All rights reserved.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
19 #include <linux/vmalloc.h>
24 #include "transaction.h"
25 #include "delayed-ref.h"
28 struct extent_inode_elem {
31 struct extent_inode_elem *next;
34 static int check_extent_in_eb(struct btrfs_key *key, struct extent_buffer *eb,
35 struct btrfs_file_extent_item *fi,
37 struct extent_inode_elem **eie)
40 struct extent_inode_elem *e;
42 if (!btrfs_file_extent_compression(eb, fi) &&
43 !btrfs_file_extent_encryption(eb, fi) &&
44 !btrfs_file_extent_other_encoding(eb, fi)) {
48 data_offset = btrfs_file_extent_offset(eb, fi);
49 data_len = btrfs_file_extent_num_bytes(eb, fi);
51 if (extent_item_pos < data_offset ||
52 extent_item_pos >= data_offset + data_len)
54 offset = extent_item_pos - data_offset;
57 e = kmalloc(sizeof(*e), GFP_NOFS);
62 e->inum = key->objectid;
63 e->offset = key->offset + offset;
69 static int find_extent_in_eb(struct extent_buffer *eb, u64 wanted_disk_byte,
71 struct extent_inode_elem **eie)
75 struct btrfs_file_extent_item *fi;
82 * from the shared data ref, we only have the leaf but we need
83 * the key. thus, we must look into all items and see that we
84 * find one (some) with a reference to our extent item.
86 nritems = btrfs_header_nritems(eb);
87 for (slot = 0; slot < nritems; ++slot) {
88 btrfs_item_key_to_cpu(eb, &key, slot);
89 if (key.type != BTRFS_EXTENT_DATA_KEY)
91 fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
92 extent_type = btrfs_file_extent_type(eb, fi);
93 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
95 /* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */
96 disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
97 if (disk_byte != wanted_disk_byte)
100 ret = check_extent_in_eb(&key, eb, fi, extent_item_pos, eie);
109 * this structure records all encountered refs on the way up to the root
111 struct __prelim_ref {
112 struct list_head list;
114 struct btrfs_key key_for_search;
117 struct extent_inode_elem *inode_list;
119 u64 wanted_disk_byte;
122 static struct kmem_cache *btrfs_prelim_ref_cache;
124 int __init btrfs_prelim_ref_init(void)
126 btrfs_prelim_ref_cache = kmem_cache_create("btrfs_prelim_ref",
127 sizeof(struct __prelim_ref),
129 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
131 if (!btrfs_prelim_ref_cache)
136 void btrfs_prelim_ref_exit(void)
138 if (btrfs_prelim_ref_cache)
139 kmem_cache_destroy(btrfs_prelim_ref_cache);
143 * the rules for all callers of this function are:
144 * - obtaining the parent is the goal
145 * - if you add a key, you must know that it is a correct key
146 * - if you cannot add the parent or a correct key, then we will look into the
147 * block later to set a correct key
151 * backref type | shared | indirect | shared | indirect
152 * information | tree | tree | data | data
153 * --------------------+--------+----------+--------+----------
154 * parent logical | y | - | - | -
155 * key to resolve | - | y | y | y
156 * tree block logical | - | - | - | -
157 * root for resolving | y | y | y | y
159 * - column 1: we've the parent -> done
160 * - column 2, 3, 4: we use the key to find the parent
162 * on disk refs (inline or keyed)
163 * ==============================
164 * backref type | shared | indirect | shared | indirect
165 * information | tree | tree | data | data
166 * --------------------+--------+----------+--------+----------
167 * parent logical | y | - | y | -
168 * key to resolve | - | - | - | y
169 * tree block logical | y | y | y | y
170 * root for resolving | - | y | y | y
172 * - column 1, 3: we've the parent -> done
173 * - column 2: we take the first key from the block to find the parent
174 * (see __add_missing_keys)
175 * - column 4: we use the key to find the parent
177 * additional information that's available but not required to find the parent
178 * block might help in merging entries to gain some speed.
181 static int __add_prelim_ref(struct list_head *head, u64 root_id,
182 struct btrfs_key *key, int level,
183 u64 parent, u64 wanted_disk_byte, int count,
186 struct __prelim_ref *ref;
188 if (root_id == BTRFS_DATA_RELOC_TREE_OBJECTID)
191 ref = kmem_cache_alloc(btrfs_prelim_ref_cache, gfp_mask);
195 ref->root_id = root_id;
197 ref->key_for_search = *key;
199 memset(&ref->key_for_search, 0, sizeof(ref->key_for_search));
201 ref->inode_list = NULL;
204 ref->parent = parent;
205 ref->wanted_disk_byte = wanted_disk_byte;
206 list_add_tail(&ref->list, head);
211 static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
212 struct ulist *parents, int level,
213 struct btrfs_key *key_for_search, u64 time_seq,
214 u64 wanted_disk_byte,
215 const u64 *extent_item_pos)
219 struct extent_buffer *eb;
220 struct btrfs_key key;
221 struct btrfs_file_extent_item *fi;
222 struct extent_inode_elem *eie = NULL, *old = NULL;
226 eb = path->nodes[level];
227 ret = ulist_add(parents, eb->start, 0, GFP_NOFS);
234 * We normally enter this function with the path already pointing to
235 * the first item to check. But sometimes, we may enter it with
236 * slot==nritems. In that case, go to the next leaf before we continue.
238 if (path->slots[0] >= btrfs_header_nritems(path->nodes[0]))
239 ret = btrfs_next_old_leaf(root, path, time_seq);
243 slot = path->slots[0];
245 btrfs_item_key_to_cpu(eb, &key, slot);
247 if (key.objectid != key_for_search->objectid ||
248 key.type != BTRFS_EXTENT_DATA_KEY)
251 fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
252 disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
254 if (disk_byte == wanted_disk_byte) {
257 if (extent_item_pos) {
258 ret = check_extent_in_eb(&key, eb, fi,
266 ret = ulist_add_merge(parents, eb->start,
268 (u64 *)&old, GFP_NOFS);
271 if (!ret && extent_item_pos) {
278 ret = btrfs_next_old_item(root, path, time_seq);
287 * resolve an indirect backref in the form (root_id, key, level)
288 * to a logical address
290 static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info,
291 struct btrfs_path *path, u64 time_seq,
292 struct __prelim_ref *ref,
293 struct ulist *parents,
294 const u64 *extent_item_pos)
296 struct btrfs_root *root;
297 struct btrfs_key root_key;
298 struct extent_buffer *eb;
301 int level = ref->level;
303 root_key.objectid = ref->root_id;
304 root_key.type = BTRFS_ROOT_ITEM_KEY;
305 root_key.offset = (u64)-1;
306 root = btrfs_read_fs_root_no_name(fs_info, &root_key);
312 root_level = btrfs_old_root_level(root, time_seq);
314 if (root_level + 1 == level)
317 path->lowest_level = level;
318 ret = btrfs_search_old_slot(root, &ref->key_for_search, path, time_seq);
319 pr_debug("search slot in root %llu (level %d, ref count %d) returned "
320 "%d for key (%llu %u %llu)\n",
321 ref->root_id, level, ref->count, ret,
322 ref->key_for_search.objectid, ref->key_for_search.type,
323 ref->key_for_search.offset);
327 eb = path->nodes[level];
329 if (WARN_ON(!level)) {
334 eb = path->nodes[level];
337 ret = add_all_parents(root, path, parents, level, &ref->key_for_search,
338 time_seq, ref->wanted_disk_byte,
341 path->lowest_level = 0;
342 btrfs_release_path(path);
347 * resolve all indirect backrefs from the list
349 static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,
350 struct btrfs_path *path, u64 time_seq,
351 struct list_head *head,
352 const u64 *extent_item_pos)
356 struct __prelim_ref *ref;
357 struct __prelim_ref *ref_safe;
358 struct __prelim_ref *new_ref;
359 struct ulist *parents;
360 struct ulist_node *node;
361 struct ulist_iterator uiter;
363 parents = ulist_alloc(GFP_NOFS);
368 * _safe allows us to insert directly after the current item without
369 * iterating over the newly inserted items.
370 * we're also allowed to re-assign ref during iteration.
372 list_for_each_entry_safe(ref, ref_safe, head, list) {
373 if (ref->parent) /* already direct */
377 err = __resolve_indirect_ref(fs_info, path, time_seq, ref,
378 parents, extent_item_pos);
384 /* we put the first parent into the ref at hand */
385 ULIST_ITER_INIT(&uiter);
386 node = ulist_next(parents, &uiter);
387 ref->parent = node ? node->val : 0;
388 ref->inode_list = node ?
389 (struct extent_inode_elem *)(uintptr_t)node->aux : NULL;
391 /* additional parents require new refs being added here */
392 while ((node = ulist_next(parents, &uiter))) {
393 new_ref = kmem_cache_alloc(btrfs_prelim_ref_cache,
399 memcpy(new_ref, ref, sizeof(*ref));
400 new_ref->parent = node->val;
401 new_ref->inode_list = (struct extent_inode_elem *)
402 (uintptr_t)node->aux;
403 list_add(&new_ref->list, &ref->list);
405 ulist_reinit(parents);
412 static inline int ref_for_same_block(struct __prelim_ref *ref1,
413 struct __prelim_ref *ref2)
415 if (ref1->level != ref2->level)
417 if (ref1->root_id != ref2->root_id)
419 if (ref1->key_for_search.type != ref2->key_for_search.type)
421 if (ref1->key_for_search.objectid != ref2->key_for_search.objectid)
423 if (ref1->key_for_search.offset != ref2->key_for_search.offset)
425 if (ref1->parent != ref2->parent)
432 * read tree blocks and add keys where required.
434 static int __add_missing_keys(struct btrfs_fs_info *fs_info,
435 struct list_head *head)
437 struct list_head *pos;
438 struct extent_buffer *eb;
440 list_for_each(pos, head) {
441 struct __prelim_ref *ref;
442 ref = list_entry(pos, struct __prelim_ref, list);
446 if (ref->key_for_search.type)
448 BUG_ON(!ref->wanted_disk_byte);
449 eb = read_tree_block(fs_info->tree_root, ref->wanted_disk_byte,
450 fs_info->tree_root->leafsize, 0);
451 if (!eb || !extent_buffer_uptodate(eb)) {
452 free_extent_buffer(eb);
455 btrfs_tree_read_lock(eb);
456 if (btrfs_header_level(eb) == 0)
457 btrfs_item_key_to_cpu(eb, &ref->key_for_search, 0);
459 btrfs_node_key_to_cpu(eb, &ref->key_for_search, 0);
460 btrfs_tree_read_unlock(eb);
461 free_extent_buffer(eb);
467 * merge two lists of backrefs and adjust counts accordingly
469 * mode = 1: merge identical keys, if key is set
470 * FIXME: if we add more keys in __add_prelim_ref, we can merge more here.
471 * additionally, we could even add a key range for the blocks we
472 * looked into to merge even more (-> replace unresolved refs by those
474 * mode = 2: merge identical parents
476 static void __merge_refs(struct list_head *head, int mode)
478 struct list_head *pos1;
480 list_for_each(pos1, head) {
481 struct list_head *n2;
482 struct list_head *pos2;
483 struct __prelim_ref *ref1;
485 ref1 = list_entry(pos1, struct __prelim_ref, list);
487 for (pos2 = pos1->next, n2 = pos2->next; pos2 != head;
488 pos2 = n2, n2 = pos2->next) {
489 struct __prelim_ref *ref2;
490 struct __prelim_ref *xchg;
491 struct extent_inode_elem *eie;
493 ref2 = list_entry(pos2, struct __prelim_ref, list);
496 if (!ref_for_same_block(ref1, ref2))
498 if (!ref1->parent && ref2->parent) {
504 if (ref1->parent != ref2->parent)
508 eie = ref1->inode_list;
509 while (eie && eie->next)
512 eie->next = ref2->inode_list;
514 ref1->inode_list = ref2->inode_list;
515 ref1->count += ref2->count;
517 list_del(&ref2->list);
518 kmem_cache_free(btrfs_prelim_ref_cache, ref2);
525 * add all currently queued delayed refs from this head whose seq nr is
526 * smaller or equal that seq to the list
528 static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
529 struct list_head *prefs)
531 struct btrfs_delayed_extent_op *extent_op = head->extent_op;
532 struct rb_node *n = &head->node.rb_node;
533 struct btrfs_key key;
534 struct btrfs_key op_key = {0};
538 if (extent_op && extent_op->update_key)
539 btrfs_disk_key_to_cpu(&op_key, &extent_op->key);
541 spin_lock(&head->lock);
542 n = rb_first(&head->ref_root);
544 struct btrfs_delayed_ref_node *node;
545 node = rb_entry(n, struct btrfs_delayed_ref_node,
551 switch (node->action) {
552 case BTRFS_ADD_DELAYED_EXTENT:
553 case BTRFS_UPDATE_DELAYED_HEAD:
556 case BTRFS_ADD_DELAYED_REF:
559 case BTRFS_DROP_DELAYED_REF:
565 switch (node->type) {
566 case BTRFS_TREE_BLOCK_REF_KEY: {
567 struct btrfs_delayed_tree_ref *ref;
569 ref = btrfs_delayed_node_to_tree_ref(node);
570 ret = __add_prelim_ref(prefs, ref->root, &op_key,
571 ref->level + 1, 0, node->bytenr,
572 node->ref_mod * sgn, GFP_ATOMIC);
575 case BTRFS_SHARED_BLOCK_REF_KEY: {
576 struct btrfs_delayed_tree_ref *ref;
578 ref = btrfs_delayed_node_to_tree_ref(node);
579 ret = __add_prelim_ref(prefs, ref->root, NULL,
580 ref->level + 1, ref->parent,
582 node->ref_mod * sgn, GFP_ATOMIC);
585 case BTRFS_EXTENT_DATA_REF_KEY: {
586 struct btrfs_delayed_data_ref *ref;
587 ref = btrfs_delayed_node_to_data_ref(node);
589 key.objectid = ref->objectid;
590 key.type = BTRFS_EXTENT_DATA_KEY;
591 key.offset = ref->offset;
592 ret = __add_prelim_ref(prefs, ref->root, &key, 0, 0,
594 node->ref_mod * sgn, GFP_ATOMIC);
597 case BTRFS_SHARED_DATA_REF_KEY: {
598 struct btrfs_delayed_data_ref *ref;
600 ref = btrfs_delayed_node_to_data_ref(node);
602 key.objectid = ref->objectid;
603 key.type = BTRFS_EXTENT_DATA_KEY;
604 key.offset = ref->offset;
605 ret = __add_prelim_ref(prefs, ref->root, &key, 0,
606 ref->parent, node->bytenr,
607 node->ref_mod * sgn, GFP_ATOMIC);
616 spin_unlock(&head->lock);
621 * add all inline backrefs for bytenr to the list
623 static int __add_inline_refs(struct btrfs_fs_info *fs_info,
624 struct btrfs_path *path, u64 bytenr,
625 int *info_level, struct list_head *prefs)
629 struct extent_buffer *leaf;
630 struct btrfs_key key;
631 struct btrfs_key found_key;
634 struct btrfs_extent_item *ei;
639 * enumerate all inline refs
641 leaf = path->nodes[0];
642 slot = path->slots[0];
644 item_size = btrfs_item_size_nr(leaf, slot);
645 BUG_ON(item_size < sizeof(*ei));
647 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
648 flags = btrfs_extent_flags(leaf, ei);
649 btrfs_item_key_to_cpu(leaf, &found_key, slot);
651 ptr = (unsigned long)(ei + 1);
652 end = (unsigned long)ei + item_size;
654 if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
655 flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
656 struct btrfs_tree_block_info *info;
658 info = (struct btrfs_tree_block_info *)ptr;
659 *info_level = btrfs_tree_block_level(leaf, info);
660 ptr += sizeof(struct btrfs_tree_block_info);
662 } else if (found_key.type == BTRFS_METADATA_ITEM_KEY) {
663 *info_level = found_key.offset;
665 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
669 struct btrfs_extent_inline_ref *iref;
673 iref = (struct btrfs_extent_inline_ref *)ptr;
674 type = btrfs_extent_inline_ref_type(leaf, iref);
675 offset = btrfs_extent_inline_ref_offset(leaf, iref);
678 case BTRFS_SHARED_BLOCK_REF_KEY:
679 ret = __add_prelim_ref(prefs, 0, NULL,
680 *info_level + 1, offset,
681 bytenr, 1, GFP_NOFS);
683 case BTRFS_SHARED_DATA_REF_KEY: {
684 struct btrfs_shared_data_ref *sdref;
687 sdref = (struct btrfs_shared_data_ref *)(iref + 1);
688 count = btrfs_shared_data_ref_count(leaf, sdref);
689 ret = __add_prelim_ref(prefs, 0, NULL, 0, offset,
690 bytenr, count, GFP_NOFS);
693 case BTRFS_TREE_BLOCK_REF_KEY:
694 ret = __add_prelim_ref(prefs, offset, NULL,
696 bytenr, 1, GFP_NOFS);
698 case BTRFS_EXTENT_DATA_REF_KEY: {
699 struct btrfs_extent_data_ref *dref;
703 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
704 count = btrfs_extent_data_ref_count(leaf, dref);
705 key.objectid = btrfs_extent_data_ref_objectid(leaf,
707 key.type = BTRFS_EXTENT_DATA_KEY;
708 key.offset = btrfs_extent_data_ref_offset(leaf, dref);
709 root = btrfs_extent_data_ref_root(leaf, dref);
710 ret = __add_prelim_ref(prefs, root, &key, 0, 0,
711 bytenr, count, GFP_NOFS);
719 ptr += btrfs_extent_inline_ref_size(type);
726 * add all non-inline backrefs for bytenr to the list
728 static int __add_keyed_refs(struct btrfs_fs_info *fs_info,
729 struct btrfs_path *path, u64 bytenr,
730 int info_level, struct list_head *prefs)
732 struct btrfs_root *extent_root = fs_info->extent_root;
735 struct extent_buffer *leaf;
736 struct btrfs_key key;
739 ret = btrfs_next_item(extent_root, path);
747 slot = path->slots[0];
748 leaf = path->nodes[0];
749 btrfs_item_key_to_cpu(leaf, &key, slot);
751 if (key.objectid != bytenr)
753 if (key.type < BTRFS_TREE_BLOCK_REF_KEY)
755 if (key.type > BTRFS_SHARED_DATA_REF_KEY)
759 case BTRFS_SHARED_BLOCK_REF_KEY:
760 ret = __add_prelim_ref(prefs, 0, NULL,
761 info_level + 1, key.offset,
762 bytenr, 1, GFP_NOFS);
764 case BTRFS_SHARED_DATA_REF_KEY: {
765 struct btrfs_shared_data_ref *sdref;
768 sdref = btrfs_item_ptr(leaf, slot,
769 struct btrfs_shared_data_ref);
770 count = btrfs_shared_data_ref_count(leaf, sdref);
771 ret = __add_prelim_ref(prefs, 0, NULL, 0, key.offset,
772 bytenr, count, GFP_NOFS);
775 case BTRFS_TREE_BLOCK_REF_KEY:
776 ret = __add_prelim_ref(prefs, key.offset, NULL,
778 bytenr, 1, GFP_NOFS);
780 case BTRFS_EXTENT_DATA_REF_KEY: {
781 struct btrfs_extent_data_ref *dref;
785 dref = btrfs_item_ptr(leaf, slot,
786 struct btrfs_extent_data_ref);
787 count = btrfs_extent_data_ref_count(leaf, dref);
788 key.objectid = btrfs_extent_data_ref_objectid(leaf,
790 key.type = BTRFS_EXTENT_DATA_KEY;
791 key.offset = btrfs_extent_data_ref_offset(leaf, dref);
792 root = btrfs_extent_data_ref_root(leaf, dref);
793 ret = __add_prelim_ref(prefs, root, &key, 0, 0,
794 bytenr, count, GFP_NOFS);
809 * this adds all existing backrefs (inline backrefs, backrefs and delayed
810 * refs) for the given bytenr to the refs list, merges duplicates and resolves
811 * indirect refs to their parent bytenr.
812 * When roots are found, they're added to the roots list
814 * FIXME some caching might speed things up
816 static int find_parent_nodes(struct btrfs_trans_handle *trans,
817 struct btrfs_fs_info *fs_info, u64 bytenr,
818 u64 time_seq, struct ulist *refs,
819 struct ulist *roots, const u64 *extent_item_pos)
821 struct btrfs_key key;
822 struct btrfs_path *path;
823 struct btrfs_delayed_ref_root *delayed_refs = NULL;
824 struct btrfs_delayed_ref_head *head;
827 struct list_head prefs_delayed;
828 struct list_head prefs;
829 struct __prelim_ref *ref;
831 INIT_LIST_HEAD(&prefs);
832 INIT_LIST_HEAD(&prefs_delayed);
834 key.objectid = bytenr;
835 key.offset = (u64)-1;
836 if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
837 key.type = BTRFS_METADATA_ITEM_KEY;
839 key.type = BTRFS_EXTENT_ITEM_KEY;
841 path = btrfs_alloc_path();
845 path->search_commit_root = 1;
848 * grab both a lock on the path and a lock on the delayed ref head.
849 * We need both to get a consistent picture of how the refs look
850 * at a specified point in time
855 ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
862 * look if there are updates for this ref queued and lock the
865 delayed_refs = &trans->transaction->delayed_refs;
866 spin_lock(&delayed_refs->lock);
867 head = btrfs_find_delayed_ref_head(trans, bytenr);
869 if (!mutex_trylock(&head->mutex)) {
870 atomic_inc(&head->node.refs);
871 spin_unlock(&delayed_refs->lock);
873 btrfs_release_path(path);
876 * Mutex was contended, block until it's
877 * released and try again
879 mutex_lock(&head->mutex);
880 mutex_unlock(&head->mutex);
881 btrfs_put_delayed_ref(&head->node);
884 spin_unlock(&delayed_refs->lock);
885 ret = __add_delayed_refs(head, time_seq,
887 mutex_unlock(&head->mutex);
891 spin_unlock(&delayed_refs->lock);
895 if (path->slots[0]) {
896 struct extent_buffer *leaf;
900 leaf = path->nodes[0];
901 slot = path->slots[0];
902 btrfs_item_key_to_cpu(leaf, &key, slot);
903 if (key.objectid == bytenr &&
904 (key.type == BTRFS_EXTENT_ITEM_KEY ||
905 key.type == BTRFS_METADATA_ITEM_KEY)) {
906 ret = __add_inline_refs(fs_info, path, bytenr,
907 &info_level, &prefs);
910 ret = __add_keyed_refs(fs_info, path, bytenr,
916 btrfs_release_path(path);
918 list_splice_init(&prefs_delayed, &prefs);
920 ret = __add_missing_keys(fs_info, &prefs);
924 __merge_refs(&prefs, 1);
926 ret = __resolve_indirect_refs(fs_info, path, time_seq, &prefs,
931 __merge_refs(&prefs, 2);
933 while (!list_empty(&prefs)) {
934 ref = list_first_entry(&prefs, struct __prelim_ref, list);
935 WARN_ON(ref->count < 0);
936 if (ref->count && ref->root_id && ref->parent == 0) {
937 /* no parent == root of tree */
938 ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS);
942 if (ref->count && ref->parent) {
943 struct extent_inode_elem *eie = NULL;
944 if (extent_item_pos && !ref->inode_list) {
946 struct extent_buffer *eb;
947 bsz = btrfs_level_size(fs_info->extent_root,
949 eb = read_tree_block(fs_info->extent_root,
950 ref->parent, bsz, 0);
951 if (!eb || !extent_buffer_uptodate(eb)) {
952 free_extent_buffer(eb);
956 ret = find_extent_in_eb(eb, bytenr,
957 *extent_item_pos, &eie);
958 free_extent_buffer(eb);
961 ref->inode_list = eie;
963 ret = ulist_add_merge(refs, ref->parent,
964 (uintptr_t)ref->inode_list,
965 (u64 *)&eie, GFP_NOFS);
968 if (!ret && extent_item_pos) {
970 * we've recorded that parent, so we must extend
971 * its inode list here
976 eie->next = ref->inode_list;
979 list_del(&ref->list);
980 kmem_cache_free(btrfs_prelim_ref_cache, ref);
984 btrfs_free_path(path);
985 while (!list_empty(&prefs)) {
986 ref = list_first_entry(&prefs, struct __prelim_ref, list);
987 list_del(&ref->list);
988 kmem_cache_free(btrfs_prelim_ref_cache, ref);
990 while (!list_empty(&prefs_delayed)) {
991 ref = list_first_entry(&prefs_delayed, struct __prelim_ref,
993 list_del(&ref->list);
994 kmem_cache_free(btrfs_prelim_ref_cache, ref);
1000 static void free_leaf_list(struct ulist *blocks)
1002 struct ulist_node *node = NULL;
1003 struct extent_inode_elem *eie;
1004 struct extent_inode_elem *eie_next;
1005 struct ulist_iterator uiter;
1007 ULIST_ITER_INIT(&uiter);
1008 while ((node = ulist_next(blocks, &uiter))) {
1011 eie = (struct extent_inode_elem *)(uintptr_t)node->aux;
1012 for (; eie; eie = eie_next) {
1013 eie_next = eie->next;
1023 * Finds all leafs with a reference to the specified combination of bytenr and
1024 * offset. key_list_head will point to a list of corresponding keys (caller must
1025 * free each list element). The leafs will be stored in the leafs ulist, which
1026 * must be freed with ulist_free.
1028 * returns 0 on success, <0 on error
1030 static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
1031 struct btrfs_fs_info *fs_info, u64 bytenr,
1032 u64 time_seq, struct ulist **leafs,
1033 const u64 *extent_item_pos)
1038 tmp = ulist_alloc(GFP_NOFS);
1041 *leafs = ulist_alloc(GFP_NOFS);
1047 ret = find_parent_nodes(trans, fs_info, bytenr,
1048 time_seq, *leafs, tmp, extent_item_pos);
1051 if (ret < 0 && ret != -ENOENT) {
1052 free_leaf_list(*leafs);
1060 * walk all backrefs for a given extent to find all roots that reference this
1061 * extent. Walking a backref means finding all extents that reference this
1062 * extent and in turn walk the backrefs of those, too. Naturally this is a
1063 * recursive process, but here it is implemented in an iterative fashion: We
1064 * find all referencing extents for the extent in question and put them on a
1065 * list. In turn, we find all referencing extents for those, further appending
1066 * to the list. The way we iterate the list allows adding more elements after
1067 * the current while iterating. The process stops when we reach the end of the
1068 * list. Found roots are added to the roots list.
1070 * returns 0 on success, < 0 on error.
1072 int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
1073 struct btrfs_fs_info *fs_info, u64 bytenr,
1074 u64 time_seq, struct ulist **roots)
1077 struct ulist_node *node = NULL;
1078 struct ulist_iterator uiter;
1081 tmp = ulist_alloc(GFP_NOFS);
1084 *roots = ulist_alloc(GFP_NOFS);
1090 ULIST_ITER_INIT(&uiter);
1092 ret = find_parent_nodes(trans, fs_info, bytenr,
1093 time_seq, tmp, *roots, NULL);
1094 if (ret < 0 && ret != -ENOENT) {
1099 node = ulist_next(tmp, &uiter);
1110 * this makes the path point to (inum INODE_ITEM ioff)
1112 int inode_item_info(u64 inum, u64 ioff, struct btrfs_root *fs_root,
1113 struct btrfs_path *path)
1115 struct btrfs_key key;
1116 return btrfs_find_item(fs_root, path, inum, ioff,
1117 BTRFS_INODE_ITEM_KEY, &key);
1120 static int inode_ref_info(u64 inum, u64 ioff, struct btrfs_root *fs_root,
1121 struct btrfs_path *path,
1122 struct btrfs_key *found_key)
1124 return btrfs_find_item(fs_root, path, inum, ioff,
1125 BTRFS_INODE_REF_KEY, found_key);
1128 int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
1129 u64 start_off, struct btrfs_path *path,
1130 struct btrfs_inode_extref **ret_extref,
1134 struct btrfs_key key;
1135 struct btrfs_key found_key;
1136 struct btrfs_inode_extref *extref;
1137 struct extent_buffer *leaf;
1140 key.objectid = inode_objectid;
1141 btrfs_set_key_type(&key, BTRFS_INODE_EXTREF_KEY);
1142 key.offset = start_off;
1144 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1149 leaf = path->nodes[0];
1150 slot = path->slots[0];
1151 if (slot >= btrfs_header_nritems(leaf)) {
1153 * If the item at offset is not found,
1154 * btrfs_search_slot will point us to the slot
1155 * where it should be inserted. In our case
1156 * that will be the slot directly before the
1157 * next INODE_REF_KEY_V2 item. In the case
1158 * that we're pointing to the last slot in a
1159 * leaf, we must move one leaf over.
1161 ret = btrfs_next_leaf(root, path);
1170 btrfs_item_key_to_cpu(leaf, &found_key, slot);
1173 * Check that we're still looking at an extended ref key for
1174 * this particular objectid. If we have different
1175 * objectid or type then there are no more to be found
1176 * in the tree and we can exit.
1179 if (found_key.objectid != inode_objectid)
1181 if (btrfs_key_type(&found_key) != BTRFS_INODE_EXTREF_KEY)
1185 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
1186 extref = (struct btrfs_inode_extref *)ptr;
1187 *ret_extref = extref;
1189 *found_off = found_key.offset;
1197 * this iterates to turn a name (from iref/extref) into a full filesystem path.
1198 * Elements of the path are separated by '/' and the path is guaranteed to be
1199 * 0-terminated. the path is only given within the current file system.
1200 * Therefore, it never starts with a '/'. the caller is responsible to provide
1201 * "size" bytes in "dest". the dest buffer will be filled backwards. finally,
1202 * the start point of the resulting string is returned. this pointer is within
1204 * in case the path buffer would overflow, the pointer is decremented further
1205 * as if output was written to the buffer, though no more output is actually
1206 * generated. that way, the caller can determine how much space would be
1207 * required for the path to fit into the buffer. in that case, the returned
1208 * value will be smaller than dest. callers must check this!
1210 char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
1211 u32 name_len, unsigned long name_off,
1212 struct extent_buffer *eb_in, u64 parent,
1213 char *dest, u32 size)
1218 s64 bytes_left = ((s64)size) - 1;
1219 struct extent_buffer *eb = eb_in;
1220 struct btrfs_key found_key;
1221 int leave_spinning = path->leave_spinning;
1222 struct btrfs_inode_ref *iref;
1224 if (bytes_left >= 0)
1225 dest[bytes_left] = '\0';
1227 path->leave_spinning = 1;
1229 bytes_left -= name_len;
1230 if (bytes_left >= 0)
1231 read_extent_buffer(eb, dest + bytes_left,
1232 name_off, name_len);
1234 btrfs_tree_read_unlock_blocking(eb);
1235 free_extent_buffer(eb);
1237 ret = inode_ref_info(parent, 0, fs_root, path, &found_key);
1243 next_inum = found_key.offset;
1245 /* regular exit ahead */
1246 if (parent == next_inum)
1249 slot = path->slots[0];
1250 eb = path->nodes[0];
1251 /* make sure we can use eb after releasing the path */
1253 atomic_inc(&eb->refs);
1254 btrfs_tree_read_lock(eb);
1255 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
1257 btrfs_release_path(path);
1258 iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
1260 name_len = btrfs_inode_ref_name_len(eb, iref);
1261 name_off = (unsigned long)(iref + 1);
1265 if (bytes_left >= 0)
1266 dest[bytes_left] = '/';
1269 btrfs_release_path(path);
1270 path->leave_spinning = leave_spinning;
1273 return ERR_PTR(ret);
1275 return dest + bytes_left;
1279 * this makes the path point to (logical EXTENT_ITEM *)
1280 * returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for
1281 * tree blocks and <0 on error.
1283 int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
1284 struct btrfs_path *path, struct btrfs_key *found_key,
1291 struct extent_buffer *eb;
1292 struct btrfs_extent_item *ei;
1293 struct btrfs_key key;
1295 if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
1296 key.type = BTRFS_METADATA_ITEM_KEY;
1298 key.type = BTRFS_EXTENT_ITEM_KEY;
1299 key.objectid = logical;
1300 key.offset = (u64)-1;
1302 ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
1305 ret = btrfs_previous_item(fs_info->extent_root, path,
1306 0, BTRFS_EXTENT_ITEM_KEY);
1310 btrfs_item_key_to_cpu(path->nodes[0], found_key, path->slots[0]);
1311 if (found_key->type == BTRFS_METADATA_ITEM_KEY)
1312 size = fs_info->extent_root->leafsize;
1313 else if (found_key->type == BTRFS_EXTENT_ITEM_KEY)
1314 size = found_key->offset;
1316 if ((found_key->type != BTRFS_EXTENT_ITEM_KEY &&
1317 found_key->type != BTRFS_METADATA_ITEM_KEY) ||
1318 found_key->objectid > logical ||
1319 found_key->objectid + size <= logical) {
1320 pr_debug("logical %llu is not within any extent\n", logical);
1324 eb = path->nodes[0];
1325 item_size = btrfs_item_size_nr(eb, path->slots[0]);
1326 BUG_ON(item_size < sizeof(*ei));
1328 ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
1329 flags = btrfs_extent_flags(eb, ei);
1331 pr_debug("logical %llu is at position %llu within the extent (%llu "
1332 "EXTENT_ITEM %llu) flags %#llx size %u\n",
1333 logical, logical - found_key->objectid, found_key->objectid,
1334 found_key->offset, flags, item_size);
1336 WARN_ON(!flags_ret);
1338 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
1339 *flags_ret = BTRFS_EXTENT_FLAG_TREE_BLOCK;
1340 else if (flags & BTRFS_EXTENT_FLAG_DATA)
1341 *flags_ret = BTRFS_EXTENT_FLAG_DATA;
1351 * helper function to iterate extent inline refs. ptr must point to a 0 value
1352 * for the first call and may be modified. it is used to track state.
1353 * if more refs exist, 0 is returned and the next call to
1354 * __get_extent_inline_ref must pass the modified ptr parameter to get the
1355 * next ref. after the last ref was processed, 1 is returned.
1356 * returns <0 on error
1358 static int __get_extent_inline_ref(unsigned long *ptr, struct extent_buffer *eb,
1359 struct btrfs_extent_item *ei, u32 item_size,
1360 struct btrfs_extent_inline_ref **out_eiref,
1365 struct btrfs_tree_block_info *info;
1369 flags = btrfs_extent_flags(eb, ei);
1370 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1371 info = (struct btrfs_tree_block_info *)(ei + 1);
1373 (struct btrfs_extent_inline_ref *)(info + 1);
1375 *out_eiref = (struct btrfs_extent_inline_ref *)(ei + 1);
1377 *ptr = (unsigned long)*out_eiref;
1378 if ((void *)*ptr >= (void *)ei + item_size)
1382 end = (unsigned long)ei + item_size;
1383 *out_eiref = (struct btrfs_extent_inline_ref *)*ptr;
1384 *out_type = btrfs_extent_inline_ref_type(eb, *out_eiref);
1386 *ptr += btrfs_extent_inline_ref_size(*out_type);
1387 WARN_ON(*ptr > end);
1389 return 1; /* last */
1395 * reads the tree block backref for an extent. tree level and root are returned
1396 * through out_level and out_root. ptr must point to a 0 value for the first
1397 * call and may be modified (see __get_extent_inline_ref comment).
1398 * returns 0 if data was provided, 1 if there was no more data to provide or
1401 int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
1402 struct btrfs_extent_item *ei, u32 item_size,
1403 u64 *out_root, u8 *out_level)
1407 struct btrfs_tree_block_info *info;
1408 struct btrfs_extent_inline_ref *eiref;
1410 if (*ptr == (unsigned long)-1)
1414 ret = __get_extent_inline_ref(ptr, eb, ei, item_size,
1419 if (type == BTRFS_TREE_BLOCK_REF_KEY ||
1420 type == BTRFS_SHARED_BLOCK_REF_KEY)
1427 /* we can treat both ref types equally here */
1428 info = (struct btrfs_tree_block_info *)(ei + 1);
1429 *out_root = btrfs_extent_inline_ref_offset(eb, eiref);
1430 *out_level = btrfs_tree_block_level(eb, info);
1433 *ptr = (unsigned long)-1;
1438 static int iterate_leaf_refs(struct extent_inode_elem *inode_list,
1439 u64 root, u64 extent_item_objectid,
1440 iterate_extent_inodes_t *iterate, void *ctx)
1442 struct extent_inode_elem *eie;
1445 for (eie = inode_list; eie; eie = eie->next) {
1446 pr_debug("ref for %llu resolved, key (%llu EXTEND_DATA %llu), "
1447 "root %llu\n", extent_item_objectid,
1448 eie->inum, eie->offset, root);
1449 ret = iterate(eie->inum, eie->offset, root, ctx);
1451 pr_debug("stopping iteration for %llu due to ret=%d\n",
1452 extent_item_objectid, ret);
1461 * calls iterate() for every inode that references the extent identified by
1462 * the given parameters.
1463 * when the iterator function returns a non-zero value, iteration stops.
1465 int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
1466 u64 extent_item_objectid, u64 extent_item_pos,
1467 int search_commit_root,
1468 iterate_extent_inodes_t *iterate, void *ctx)
1471 struct btrfs_trans_handle *trans = NULL;
1472 struct ulist *refs = NULL;
1473 struct ulist *roots = NULL;
1474 struct ulist_node *ref_node = NULL;
1475 struct ulist_node *root_node = NULL;
1476 struct seq_list tree_mod_seq_elem = {};
1477 struct ulist_iterator ref_uiter;
1478 struct ulist_iterator root_uiter;
1480 pr_debug("resolving all inodes for extent %llu\n",
1481 extent_item_objectid);
1483 if (!search_commit_root) {
1484 trans = btrfs_join_transaction(fs_info->extent_root);
1486 return PTR_ERR(trans);
1487 btrfs_get_tree_mod_seq(fs_info, &tree_mod_seq_elem);
1490 ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid,
1491 tree_mod_seq_elem.seq, &refs,
1496 ULIST_ITER_INIT(&ref_uiter);
1497 while (!ret && (ref_node = ulist_next(refs, &ref_uiter))) {
1498 ret = btrfs_find_all_roots(trans, fs_info, ref_node->val,
1499 tree_mod_seq_elem.seq, &roots);
1502 ULIST_ITER_INIT(&root_uiter);
1503 while (!ret && (root_node = ulist_next(roots, &root_uiter))) {
1504 pr_debug("root %llu references leaf %llu, data list "
1505 "%#llx\n", root_node->val, ref_node->val,
1507 ret = iterate_leaf_refs((struct extent_inode_elem *)
1508 (uintptr_t)ref_node->aux,
1510 extent_item_objectid,
1516 free_leaf_list(refs);
1518 if (!search_commit_root) {
1519 btrfs_put_tree_mod_seq(fs_info, &tree_mod_seq_elem);
1520 btrfs_end_transaction(trans, fs_info->extent_root);
1526 int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
1527 struct btrfs_path *path,
1528 iterate_extent_inodes_t *iterate, void *ctx)
1531 u64 extent_item_pos;
1533 struct btrfs_key found_key;
1534 int search_commit_root = path->search_commit_root;
1536 ret = extent_from_logical(fs_info, logical, path, &found_key, &flags);
1537 btrfs_release_path(path);
1540 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
1543 extent_item_pos = logical - found_key.objectid;
1544 ret = iterate_extent_inodes(fs_info, found_key.objectid,
1545 extent_item_pos, search_commit_root,
1551 typedef int (iterate_irefs_t)(u64 parent, u32 name_len, unsigned long name_off,
1552 struct extent_buffer *eb, void *ctx);
1554 static int iterate_inode_refs(u64 inum, struct btrfs_root *fs_root,
1555 struct btrfs_path *path,
1556 iterate_irefs_t *iterate, void *ctx)
1565 struct extent_buffer *eb;
1566 struct btrfs_item *item;
1567 struct btrfs_inode_ref *iref;
1568 struct btrfs_key found_key;
1571 ret = inode_ref_info(inum, parent ? parent+1 : 0, fs_root, path,
1576 ret = found ? 0 : -ENOENT;
1581 parent = found_key.offset;
1582 slot = path->slots[0];
1583 eb = btrfs_clone_extent_buffer(path->nodes[0]);
1588 extent_buffer_get(eb);
1589 btrfs_tree_read_lock(eb);
1590 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
1591 btrfs_release_path(path);
1593 item = btrfs_item_nr(slot);
1594 iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
1596 for (cur = 0; cur < btrfs_item_size(eb, item); cur += len) {
1597 name_len = btrfs_inode_ref_name_len(eb, iref);
1598 /* path must be released before calling iterate()! */
1599 pr_debug("following ref at offset %u for inode %llu in "
1600 "tree %llu\n", cur, found_key.objectid,
1602 ret = iterate(parent, name_len,
1603 (unsigned long)(iref + 1), eb, ctx);
1606 len = sizeof(*iref) + name_len;
1607 iref = (struct btrfs_inode_ref *)((char *)iref + len);
1609 btrfs_tree_read_unlock_blocking(eb);
1610 free_extent_buffer(eb);
1613 btrfs_release_path(path);
1618 static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root,
1619 struct btrfs_path *path,
1620 iterate_irefs_t *iterate, void *ctx)
1627 struct extent_buffer *eb;
1628 struct btrfs_inode_extref *extref;
1629 struct extent_buffer *leaf;
1635 ret = btrfs_find_one_extref(fs_root, inum, offset, path, &extref,
1640 ret = found ? 0 : -ENOENT;
1645 slot = path->slots[0];
1646 eb = btrfs_clone_extent_buffer(path->nodes[0]);
1651 extent_buffer_get(eb);
1653 btrfs_tree_read_lock(eb);
1654 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
1655 btrfs_release_path(path);
1657 leaf = path->nodes[0];
1658 item_size = btrfs_item_size_nr(leaf, slot);
1659 ptr = btrfs_item_ptr_offset(leaf, slot);
1662 while (cur_offset < item_size) {
1665 extref = (struct btrfs_inode_extref *)(ptr + cur_offset);
1666 parent = btrfs_inode_extref_parent(eb, extref);
1667 name_len = btrfs_inode_extref_name_len(eb, extref);
1668 ret = iterate(parent, name_len,
1669 (unsigned long)&extref->name, eb, ctx);
1673 cur_offset += btrfs_inode_extref_name_len(leaf, extref);
1674 cur_offset += sizeof(*extref);
1676 btrfs_tree_read_unlock_blocking(eb);
1677 free_extent_buffer(eb);
1682 btrfs_release_path(path);
1687 static int iterate_irefs(u64 inum, struct btrfs_root *fs_root,
1688 struct btrfs_path *path, iterate_irefs_t *iterate,
1694 ret = iterate_inode_refs(inum, fs_root, path, iterate, ctx);
1697 else if (ret != -ENOENT)
1700 ret = iterate_inode_extrefs(inum, fs_root, path, iterate, ctx);
1701 if (ret == -ENOENT && found_refs)
1708 * returns 0 if the path could be dumped (probably truncated)
1709 * returns <0 in case of an error
1711 static int inode_to_path(u64 inum, u32 name_len, unsigned long name_off,
1712 struct extent_buffer *eb, void *ctx)
1714 struct inode_fs_paths *ipath = ctx;
1717 int i = ipath->fspath->elem_cnt;
1718 const int s_ptr = sizeof(char *);
1721 bytes_left = ipath->fspath->bytes_left > s_ptr ?
1722 ipath->fspath->bytes_left - s_ptr : 0;
1724 fspath_min = (char *)ipath->fspath->val + (i + 1) * s_ptr;
1725 fspath = btrfs_ref_to_path(ipath->fs_root, ipath->btrfs_path, name_len,
1726 name_off, eb, inum, fspath_min, bytes_left);
1728 return PTR_ERR(fspath);
1730 if (fspath > fspath_min) {
1731 ipath->fspath->val[i] = (u64)(unsigned long)fspath;
1732 ++ipath->fspath->elem_cnt;
1733 ipath->fspath->bytes_left = fspath - fspath_min;
1735 ++ipath->fspath->elem_missed;
1736 ipath->fspath->bytes_missing += fspath_min - fspath;
1737 ipath->fspath->bytes_left = 0;
1744 * this dumps all file system paths to the inode into the ipath struct, provided
1745 * is has been created large enough. each path is zero-terminated and accessed
1746 * from ipath->fspath->val[i].
1747 * when it returns, there are ipath->fspath->elem_cnt number of paths available
1748 * in ipath->fspath->val[]. when the allocated space wasn't sufficient, the
1749 * number of missed paths in recored in ipath->fspath->elem_missed, otherwise,
1750 * it's zero. ipath->fspath->bytes_missing holds the number of bytes that would
1751 * have been needed to return all paths.
1753 int paths_from_inode(u64 inum, struct inode_fs_paths *ipath)
1755 return iterate_irefs(inum, ipath->fs_root, ipath->btrfs_path,
1756 inode_to_path, ipath);
1759 struct btrfs_data_container *init_data_container(u32 total_bytes)
1761 struct btrfs_data_container *data;
1764 alloc_bytes = max_t(size_t, total_bytes, sizeof(*data));
1765 data = vmalloc(alloc_bytes);
1767 return ERR_PTR(-ENOMEM);
1769 if (total_bytes >= sizeof(*data)) {
1770 data->bytes_left = total_bytes - sizeof(*data);
1771 data->bytes_missing = 0;
1773 data->bytes_missing = sizeof(*data) - total_bytes;
1774 data->bytes_left = 0;
1778 data->elem_missed = 0;
1784 * allocates space to return multiple file system paths for an inode.
1785 * total_bytes to allocate are passed, note that space usable for actual path
1786 * information will be total_bytes - sizeof(struct inode_fs_paths).
1787 * the returned pointer must be freed with free_ipath() in the end.
1789 struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root,
1790 struct btrfs_path *path)
1792 struct inode_fs_paths *ifp;
1793 struct btrfs_data_container *fspath;
1795 fspath = init_data_container(total_bytes);
1797 return (void *)fspath;
1799 ifp = kmalloc(sizeof(*ifp), GFP_NOFS);
1802 return ERR_PTR(-ENOMEM);
1805 ifp->btrfs_path = path;
1806 ifp->fspath = fspath;
1807 ifp->fs_root = fs_root;
1812 void free_ipath(struct inode_fs_paths *ipath)
1816 vfree(ipath->fspath);