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 /* Just an arbitrary number so we can be sure this happened */
29 #define BACKREF_FOUND_SHARED 6
31 struct extent_inode_elem {
34 struct extent_inode_elem *next;
37 static int check_extent_in_eb(struct btrfs_key *key, struct extent_buffer *eb,
38 struct btrfs_file_extent_item *fi,
40 struct extent_inode_elem **eie)
43 struct extent_inode_elem *e;
45 if (!btrfs_file_extent_compression(eb, fi) &&
46 !btrfs_file_extent_encryption(eb, fi) &&
47 !btrfs_file_extent_other_encoding(eb, fi)) {
51 data_offset = btrfs_file_extent_offset(eb, fi);
52 data_len = btrfs_file_extent_num_bytes(eb, fi);
54 if (extent_item_pos < data_offset ||
55 extent_item_pos >= data_offset + data_len)
57 offset = extent_item_pos - data_offset;
60 e = kmalloc(sizeof(*e), GFP_NOFS);
65 e->inum = key->objectid;
66 e->offset = key->offset + offset;
72 static void free_inode_elem_list(struct extent_inode_elem *eie)
74 struct extent_inode_elem *eie_next;
76 for (; eie; eie = eie_next) {
82 static int find_extent_in_eb(struct extent_buffer *eb, u64 wanted_disk_byte,
84 struct extent_inode_elem **eie)
88 struct btrfs_file_extent_item *fi;
95 * from the shared data ref, we only have the leaf but we need
96 * the key. thus, we must look into all items and see that we
97 * find one (some) with a reference to our extent item.
99 nritems = btrfs_header_nritems(eb);
100 for (slot = 0; slot < nritems; ++slot) {
101 btrfs_item_key_to_cpu(eb, &key, slot);
102 if (key.type != BTRFS_EXTENT_DATA_KEY)
104 fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
105 extent_type = btrfs_file_extent_type(eb, fi);
106 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
108 /* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */
109 disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
110 if (disk_byte != wanted_disk_byte)
113 ret = check_extent_in_eb(&key, eb, fi, extent_item_pos, eie);
122 * this structure records all encountered refs on the way up to the root
124 struct __prelim_ref {
125 struct list_head list;
127 struct btrfs_key key_for_search;
130 struct extent_inode_elem *inode_list;
132 u64 wanted_disk_byte;
135 static struct kmem_cache *btrfs_prelim_ref_cache;
137 int __init btrfs_prelim_ref_init(void)
139 btrfs_prelim_ref_cache = kmem_cache_create("btrfs_prelim_ref",
140 sizeof(struct __prelim_ref),
142 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
144 if (!btrfs_prelim_ref_cache)
149 void btrfs_prelim_ref_exit(void)
151 if (btrfs_prelim_ref_cache)
152 kmem_cache_destroy(btrfs_prelim_ref_cache);
156 * the rules for all callers of this function are:
157 * - obtaining the parent is the goal
158 * - if you add a key, you must know that it is a correct key
159 * - if you cannot add the parent or a correct key, then we will look into the
160 * block later to set a correct key
164 * backref type | shared | indirect | shared | indirect
165 * information | tree | tree | data | data
166 * --------------------+--------+----------+--------+----------
167 * parent logical | y | - | - | -
168 * key to resolve | - | y | y | y
169 * tree block logical | - | - | - | -
170 * root for resolving | y | y | y | y
172 * - column 1: we've the parent -> done
173 * - column 2, 3, 4: we use the key to find the parent
175 * on disk refs (inline or keyed)
176 * ==============================
177 * backref type | shared | indirect | shared | indirect
178 * information | tree | tree | data | data
179 * --------------------+--------+----------+--------+----------
180 * parent logical | y | - | y | -
181 * key to resolve | - | - | - | y
182 * tree block logical | y | y | y | y
183 * root for resolving | - | y | y | y
185 * - column 1, 3: we've the parent -> done
186 * - column 2: we take the first key from the block to find the parent
187 * (see __add_missing_keys)
188 * - column 4: we use the key to find the parent
190 * additional information that's available but not required to find the parent
191 * block might help in merging entries to gain some speed.
194 static int __add_prelim_ref(struct list_head *head, u64 root_id,
195 struct btrfs_key *key, int level,
196 u64 parent, u64 wanted_disk_byte, int count,
199 struct __prelim_ref *ref;
201 if (root_id == BTRFS_DATA_RELOC_TREE_OBJECTID)
204 ref = kmem_cache_alloc(btrfs_prelim_ref_cache, gfp_mask);
208 ref->root_id = root_id;
210 ref->key_for_search = *key;
212 memset(&ref->key_for_search, 0, sizeof(ref->key_for_search));
214 ref->inode_list = NULL;
217 ref->parent = parent;
218 ref->wanted_disk_byte = wanted_disk_byte;
219 list_add_tail(&ref->list, head);
224 static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
225 struct ulist *parents, struct __prelim_ref *ref,
226 int level, u64 time_seq, const u64 *extent_item_pos,
231 struct extent_buffer *eb;
232 struct btrfs_key key;
233 struct btrfs_key *key_for_search = &ref->key_for_search;
234 struct btrfs_file_extent_item *fi;
235 struct extent_inode_elem *eie = NULL, *old = NULL;
237 u64 wanted_disk_byte = ref->wanted_disk_byte;
241 eb = path->nodes[level];
242 ret = ulist_add(parents, eb->start, 0, GFP_NOFS);
249 * We normally enter this function with the path already pointing to
250 * the first item to check. But sometimes, we may enter it with
251 * slot==nritems. In that case, go to the next leaf before we continue.
253 if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
254 if (time_seq == (u64)-1)
255 ret = btrfs_next_leaf(root, path);
257 ret = btrfs_next_old_leaf(root, path, time_seq);
260 while (!ret && count < total_refs) {
262 slot = path->slots[0];
264 btrfs_item_key_to_cpu(eb, &key, slot);
266 if (key.objectid != key_for_search->objectid ||
267 key.type != BTRFS_EXTENT_DATA_KEY)
270 fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
271 disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
273 if (disk_byte == wanted_disk_byte) {
277 if (extent_item_pos) {
278 ret = check_extent_in_eb(&key, eb, fi,
286 ret = ulist_add_merge_ptr(parents, eb->start,
287 eie, (void **)&old, GFP_NOFS);
290 if (!ret && extent_item_pos) {
298 if (time_seq == (u64)-1)
299 ret = btrfs_next_item(root, path);
301 ret = btrfs_next_old_item(root, path, time_seq);
307 free_inode_elem_list(eie);
312 * resolve an indirect backref in the form (root_id, key, level)
313 * to a logical address
315 static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info,
316 struct btrfs_path *path, u64 time_seq,
317 struct __prelim_ref *ref,
318 struct ulist *parents,
319 const u64 *extent_item_pos, u64 total_refs)
321 struct btrfs_root *root;
322 struct btrfs_key root_key;
323 struct extent_buffer *eb;
326 int level = ref->level;
329 root_key.objectid = ref->root_id;
330 root_key.type = BTRFS_ROOT_ITEM_KEY;
331 root_key.offset = (u64)-1;
333 index = srcu_read_lock(&fs_info->subvol_srcu);
335 root = btrfs_read_fs_root_no_name(fs_info, &root_key);
337 srcu_read_unlock(&fs_info->subvol_srcu, index);
342 if (path->search_commit_root)
343 root_level = btrfs_header_level(root->commit_root);
344 else if (time_seq == (u64)-1)
345 root_level = btrfs_header_level(root->node);
347 root_level = btrfs_old_root_level(root, time_seq);
349 if (root_level + 1 == level) {
350 srcu_read_unlock(&fs_info->subvol_srcu, index);
354 path->lowest_level = level;
355 if (time_seq == (u64)-1)
356 ret = btrfs_search_slot(NULL, root, &ref->key_for_search, path,
359 ret = btrfs_search_old_slot(root, &ref->key_for_search, path,
362 /* root node has been locked, we can release @subvol_srcu safely here */
363 srcu_read_unlock(&fs_info->subvol_srcu, index);
365 pr_debug("search slot in root %llu (level %d, ref count %d) returned "
366 "%d for key (%llu %u %llu)\n",
367 ref->root_id, level, ref->count, ret,
368 ref->key_for_search.objectid, ref->key_for_search.type,
369 ref->key_for_search.offset);
373 eb = path->nodes[level];
375 if (WARN_ON(!level)) {
380 eb = path->nodes[level];
383 ret = add_all_parents(root, path, parents, ref, level, time_seq,
384 extent_item_pos, total_refs);
386 path->lowest_level = 0;
387 btrfs_release_path(path);
392 * resolve all indirect backrefs from the list
394 static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,
395 struct btrfs_path *path, u64 time_seq,
396 struct list_head *head,
397 const u64 *extent_item_pos, u64 total_refs,
402 struct __prelim_ref *ref;
403 struct __prelim_ref *ref_safe;
404 struct __prelim_ref *new_ref;
405 struct ulist *parents;
406 struct ulist_node *node;
407 struct ulist_iterator uiter;
409 parents = ulist_alloc(GFP_NOFS);
414 * _safe allows us to insert directly after the current item without
415 * iterating over the newly inserted items.
416 * we're also allowed to re-assign ref during iteration.
418 list_for_each_entry_safe(ref, ref_safe, head, list) {
419 if (ref->parent) /* already direct */
423 if (root_objectid && ref->root_id != root_objectid) {
424 ret = BACKREF_FOUND_SHARED;
427 err = __resolve_indirect_ref(fs_info, path, time_seq, ref,
428 parents, extent_item_pos,
431 * we can only tolerate ENOENT,otherwise,we should catch error
432 * and return directly.
434 if (err == -ENOENT) {
441 /* we put the first parent into the ref at hand */
442 ULIST_ITER_INIT(&uiter);
443 node = ulist_next(parents, &uiter);
444 ref->parent = node ? node->val : 0;
445 ref->inode_list = node ?
446 (struct extent_inode_elem *)(uintptr_t)node->aux : NULL;
448 /* additional parents require new refs being added here */
449 while ((node = ulist_next(parents, &uiter))) {
450 new_ref = kmem_cache_alloc(btrfs_prelim_ref_cache,
456 memcpy(new_ref, ref, sizeof(*ref));
457 new_ref->parent = node->val;
458 new_ref->inode_list = (struct extent_inode_elem *)
459 (uintptr_t)node->aux;
460 list_add(&new_ref->list, &ref->list);
462 ulist_reinit(parents);
469 static inline int ref_for_same_block(struct __prelim_ref *ref1,
470 struct __prelim_ref *ref2)
472 if (ref1->level != ref2->level)
474 if (ref1->root_id != ref2->root_id)
476 if (ref1->key_for_search.type != ref2->key_for_search.type)
478 if (ref1->key_for_search.objectid != ref2->key_for_search.objectid)
480 if (ref1->key_for_search.offset != ref2->key_for_search.offset)
482 if (ref1->parent != ref2->parent)
489 * read tree blocks and add keys where required.
491 static int __add_missing_keys(struct btrfs_fs_info *fs_info,
492 struct list_head *head)
494 struct list_head *pos;
495 struct extent_buffer *eb;
497 list_for_each(pos, head) {
498 struct __prelim_ref *ref;
499 ref = list_entry(pos, struct __prelim_ref, list);
503 if (ref->key_for_search.type)
505 BUG_ON(!ref->wanted_disk_byte);
506 eb = read_tree_block(fs_info->tree_root, ref->wanted_disk_byte,
510 } else if (!extent_buffer_uptodate(eb)) {
511 free_extent_buffer(eb);
514 btrfs_tree_read_lock(eb);
515 if (btrfs_header_level(eb) == 0)
516 btrfs_item_key_to_cpu(eb, &ref->key_for_search, 0);
518 btrfs_node_key_to_cpu(eb, &ref->key_for_search, 0);
519 btrfs_tree_read_unlock(eb);
520 free_extent_buffer(eb);
526 * merge backrefs and adjust counts accordingly
528 * mode = 1: merge identical keys, if key is set
529 * FIXME: if we add more keys in __add_prelim_ref, we can merge more here.
530 * additionally, we could even add a key range for the blocks we
531 * looked into to merge even more (-> replace unresolved refs by those
533 * mode = 2: merge identical parents
535 static void __merge_refs(struct list_head *head, int mode)
537 struct list_head *pos1;
539 list_for_each(pos1, head) {
540 struct list_head *n2;
541 struct list_head *pos2;
542 struct __prelim_ref *ref1;
544 ref1 = list_entry(pos1, struct __prelim_ref, list);
546 for (pos2 = pos1->next, n2 = pos2->next; pos2 != head;
547 pos2 = n2, n2 = pos2->next) {
548 struct __prelim_ref *ref2;
549 struct __prelim_ref *xchg;
550 struct extent_inode_elem *eie;
552 ref2 = list_entry(pos2, struct __prelim_ref, list);
554 if (!ref_for_same_block(ref1, ref2))
557 if (!ref1->parent && ref2->parent) {
563 if (ref1->parent != ref2->parent)
567 eie = ref1->inode_list;
568 while (eie && eie->next)
571 eie->next = ref2->inode_list;
573 ref1->inode_list = ref2->inode_list;
574 ref1->count += ref2->count;
576 list_del(&ref2->list);
577 kmem_cache_free(btrfs_prelim_ref_cache, ref2);
584 * add all currently queued delayed refs from this head whose seq nr is
585 * smaller or equal that seq to the list
587 static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
588 struct list_head *prefs, u64 *total_refs,
591 struct btrfs_delayed_ref_node *node;
592 struct btrfs_delayed_extent_op *extent_op = head->extent_op;
593 struct btrfs_key key;
594 struct btrfs_key op_key = {0};
598 if (extent_op && extent_op->update_key)
599 btrfs_disk_key_to_cpu(&op_key, &extent_op->key);
601 spin_lock(&head->lock);
602 list_for_each_entry(node, &head->ref_list, list) {
606 switch (node->action) {
607 case BTRFS_ADD_DELAYED_EXTENT:
608 case BTRFS_UPDATE_DELAYED_HEAD:
611 case BTRFS_ADD_DELAYED_REF:
614 case BTRFS_DROP_DELAYED_REF:
620 *total_refs += (node->ref_mod * sgn);
621 switch (node->type) {
622 case BTRFS_TREE_BLOCK_REF_KEY: {
623 struct btrfs_delayed_tree_ref *ref;
625 ref = btrfs_delayed_node_to_tree_ref(node);
626 ret = __add_prelim_ref(prefs, ref->root, &op_key,
627 ref->level + 1, 0, node->bytenr,
628 node->ref_mod * sgn, GFP_ATOMIC);
631 case BTRFS_SHARED_BLOCK_REF_KEY: {
632 struct btrfs_delayed_tree_ref *ref;
634 ref = btrfs_delayed_node_to_tree_ref(node);
635 ret = __add_prelim_ref(prefs, ref->root, NULL,
636 ref->level + 1, ref->parent,
638 node->ref_mod * sgn, GFP_ATOMIC);
641 case BTRFS_EXTENT_DATA_REF_KEY: {
642 struct btrfs_delayed_data_ref *ref;
643 ref = btrfs_delayed_node_to_data_ref(node);
645 key.objectid = ref->objectid;
646 key.type = BTRFS_EXTENT_DATA_KEY;
647 key.offset = ref->offset;
650 * Found a inum that doesn't match our known inum, we
653 if (inum && ref->objectid != inum) {
654 ret = BACKREF_FOUND_SHARED;
658 ret = __add_prelim_ref(prefs, ref->root, &key, 0, 0,
660 node->ref_mod * sgn, GFP_ATOMIC);
663 case BTRFS_SHARED_DATA_REF_KEY: {
664 struct btrfs_delayed_data_ref *ref;
666 ref = btrfs_delayed_node_to_data_ref(node);
668 key.objectid = ref->objectid;
669 key.type = BTRFS_EXTENT_DATA_KEY;
670 key.offset = ref->offset;
671 ret = __add_prelim_ref(prefs, ref->root, &key, 0,
672 ref->parent, node->bytenr,
673 node->ref_mod * sgn, GFP_ATOMIC);
682 spin_unlock(&head->lock);
687 * add all inline backrefs for bytenr to the list
689 static int __add_inline_refs(struct btrfs_fs_info *fs_info,
690 struct btrfs_path *path, u64 bytenr,
691 int *info_level, struct list_head *prefs,
692 u64 *total_refs, u64 inum)
696 struct extent_buffer *leaf;
697 struct btrfs_key key;
698 struct btrfs_key found_key;
701 struct btrfs_extent_item *ei;
706 * enumerate all inline refs
708 leaf = path->nodes[0];
709 slot = path->slots[0];
711 item_size = btrfs_item_size_nr(leaf, slot);
712 BUG_ON(item_size < sizeof(*ei));
714 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
715 flags = btrfs_extent_flags(leaf, ei);
716 *total_refs += btrfs_extent_refs(leaf, ei);
717 btrfs_item_key_to_cpu(leaf, &found_key, slot);
719 ptr = (unsigned long)(ei + 1);
720 end = (unsigned long)ei + item_size;
722 if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
723 flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
724 struct btrfs_tree_block_info *info;
726 info = (struct btrfs_tree_block_info *)ptr;
727 *info_level = btrfs_tree_block_level(leaf, info);
728 ptr += sizeof(struct btrfs_tree_block_info);
730 } else if (found_key.type == BTRFS_METADATA_ITEM_KEY) {
731 *info_level = found_key.offset;
733 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
737 struct btrfs_extent_inline_ref *iref;
741 iref = (struct btrfs_extent_inline_ref *)ptr;
742 type = btrfs_extent_inline_ref_type(leaf, iref);
743 offset = btrfs_extent_inline_ref_offset(leaf, iref);
746 case BTRFS_SHARED_BLOCK_REF_KEY:
747 ret = __add_prelim_ref(prefs, 0, NULL,
748 *info_level + 1, offset,
749 bytenr, 1, GFP_NOFS);
751 case BTRFS_SHARED_DATA_REF_KEY: {
752 struct btrfs_shared_data_ref *sdref;
755 sdref = (struct btrfs_shared_data_ref *)(iref + 1);
756 count = btrfs_shared_data_ref_count(leaf, sdref);
757 ret = __add_prelim_ref(prefs, 0, NULL, 0, offset,
758 bytenr, count, GFP_NOFS);
761 case BTRFS_TREE_BLOCK_REF_KEY:
762 ret = __add_prelim_ref(prefs, offset, NULL,
764 bytenr, 1, GFP_NOFS);
766 case BTRFS_EXTENT_DATA_REF_KEY: {
767 struct btrfs_extent_data_ref *dref;
771 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
772 count = btrfs_extent_data_ref_count(leaf, dref);
773 key.objectid = btrfs_extent_data_ref_objectid(leaf,
775 key.type = BTRFS_EXTENT_DATA_KEY;
776 key.offset = btrfs_extent_data_ref_offset(leaf, dref);
778 if (inum && key.objectid != inum) {
779 ret = BACKREF_FOUND_SHARED;
783 root = btrfs_extent_data_ref_root(leaf, dref);
784 ret = __add_prelim_ref(prefs, root, &key, 0, 0,
785 bytenr, count, GFP_NOFS);
793 ptr += btrfs_extent_inline_ref_size(type);
800 * add all non-inline backrefs for bytenr to the list
802 static int __add_keyed_refs(struct btrfs_fs_info *fs_info,
803 struct btrfs_path *path, u64 bytenr,
804 int info_level, struct list_head *prefs, u64 inum)
806 struct btrfs_root *extent_root = fs_info->extent_root;
809 struct extent_buffer *leaf;
810 struct btrfs_key key;
813 ret = btrfs_next_item(extent_root, path);
821 slot = path->slots[0];
822 leaf = path->nodes[0];
823 btrfs_item_key_to_cpu(leaf, &key, slot);
825 if (key.objectid != bytenr)
827 if (key.type < BTRFS_TREE_BLOCK_REF_KEY)
829 if (key.type > BTRFS_SHARED_DATA_REF_KEY)
833 case BTRFS_SHARED_BLOCK_REF_KEY:
834 ret = __add_prelim_ref(prefs, 0, NULL,
835 info_level + 1, key.offset,
836 bytenr, 1, GFP_NOFS);
838 case BTRFS_SHARED_DATA_REF_KEY: {
839 struct btrfs_shared_data_ref *sdref;
842 sdref = btrfs_item_ptr(leaf, slot,
843 struct btrfs_shared_data_ref);
844 count = btrfs_shared_data_ref_count(leaf, sdref);
845 ret = __add_prelim_ref(prefs, 0, NULL, 0, key.offset,
846 bytenr, count, GFP_NOFS);
849 case BTRFS_TREE_BLOCK_REF_KEY:
850 ret = __add_prelim_ref(prefs, key.offset, NULL,
852 bytenr, 1, GFP_NOFS);
854 case BTRFS_EXTENT_DATA_REF_KEY: {
855 struct btrfs_extent_data_ref *dref;
859 dref = btrfs_item_ptr(leaf, slot,
860 struct btrfs_extent_data_ref);
861 count = btrfs_extent_data_ref_count(leaf, dref);
862 key.objectid = btrfs_extent_data_ref_objectid(leaf,
864 key.type = BTRFS_EXTENT_DATA_KEY;
865 key.offset = btrfs_extent_data_ref_offset(leaf, dref);
867 if (inum && key.objectid != inum) {
868 ret = BACKREF_FOUND_SHARED;
872 root = btrfs_extent_data_ref_root(leaf, dref);
873 ret = __add_prelim_ref(prefs, root, &key, 0, 0,
874 bytenr, count, GFP_NOFS);
889 * this adds all existing backrefs (inline backrefs, backrefs and delayed
890 * refs) for the given bytenr to the refs list, merges duplicates and resolves
891 * indirect refs to their parent bytenr.
892 * When roots are found, they're added to the roots list
894 * NOTE: This can return values > 0
896 * If time_seq is set to (u64)-1, it will not search delayed_refs, and behave
897 * much like trans == NULL case, the difference only lies in it will not
899 * The special case is for qgroup to search roots in commit_transaction().
901 * FIXME some caching might speed things up
903 static int find_parent_nodes(struct btrfs_trans_handle *trans,
904 struct btrfs_fs_info *fs_info, u64 bytenr,
905 u64 time_seq, struct ulist *refs,
906 struct ulist *roots, const u64 *extent_item_pos,
907 u64 root_objectid, u64 inum)
909 struct btrfs_key key;
910 struct btrfs_path *path;
911 struct btrfs_delayed_ref_root *delayed_refs = NULL;
912 struct btrfs_delayed_ref_head *head;
915 struct list_head prefs_delayed;
916 struct list_head prefs;
917 struct __prelim_ref *ref;
918 struct extent_inode_elem *eie = NULL;
921 INIT_LIST_HEAD(&prefs);
922 INIT_LIST_HEAD(&prefs_delayed);
924 key.objectid = bytenr;
925 key.offset = (u64)-1;
926 if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
927 key.type = BTRFS_METADATA_ITEM_KEY;
929 key.type = BTRFS_EXTENT_ITEM_KEY;
931 path = btrfs_alloc_path();
935 path->search_commit_root = 1;
936 path->skip_locking = 1;
939 if (time_seq == (u64)-1)
940 path->skip_locking = 1;
943 * grab both a lock on the path and a lock on the delayed ref head.
944 * We need both to get a consistent picture of how the refs look
945 * at a specified point in time
950 ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
955 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
956 if (trans && likely(trans->type != __TRANS_DUMMY) &&
957 time_seq != (u64)-1) {
959 if (trans && time_seq != (u64)-1) {
962 * look if there are updates for this ref queued and lock the
965 delayed_refs = &trans->transaction->delayed_refs;
966 spin_lock(&delayed_refs->lock);
967 head = btrfs_find_delayed_ref_head(trans, bytenr);
969 if (!mutex_trylock(&head->mutex)) {
970 atomic_inc(&head->node.refs);
971 spin_unlock(&delayed_refs->lock);
973 btrfs_release_path(path);
976 * Mutex was contended, block until it's
977 * released and try again
979 mutex_lock(&head->mutex);
980 mutex_unlock(&head->mutex);
981 btrfs_put_delayed_ref(&head->node);
984 spin_unlock(&delayed_refs->lock);
985 ret = __add_delayed_refs(head, time_seq,
986 &prefs_delayed, &total_refs,
988 mutex_unlock(&head->mutex);
992 spin_unlock(&delayed_refs->lock);
996 if (path->slots[0]) {
997 struct extent_buffer *leaf;
1001 leaf = path->nodes[0];
1002 slot = path->slots[0];
1003 btrfs_item_key_to_cpu(leaf, &key, slot);
1004 if (key.objectid == bytenr &&
1005 (key.type == BTRFS_EXTENT_ITEM_KEY ||
1006 key.type == BTRFS_METADATA_ITEM_KEY)) {
1007 ret = __add_inline_refs(fs_info, path, bytenr,
1008 &info_level, &prefs,
1012 ret = __add_keyed_refs(fs_info, path, bytenr,
1013 info_level, &prefs, inum);
1018 btrfs_release_path(path);
1020 list_splice_init(&prefs_delayed, &prefs);
1022 ret = __add_missing_keys(fs_info, &prefs);
1026 __merge_refs(&prefs, 1);
1028 ret = __resolve_indirect_refs(fs_info, path, time_seq, &prefs,
1029 extent_item_pos, total_refs,
1034 __merge_refs(&prefs, 2);
1036 while (!list_empty(&prefs)) {
1037 ref = list_first_entry(&prefs, struct __prelim_ref, list);
1038 WARN_ON(ref->count < 0);
1039 if (roots && ref->count && ref->root_id && ref->parent == 0) {
1040 if (root_objectid && ref->root_id != root_objectid) {
1041 ret = BACKREF_FOUND_SHARED;
1045 /* no parent == root of tree */
1046 ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS);
1050 if (ref->count && ref->parent) {
1051 if (extent_item_pos && !ref->inode_list &&
1053 struct extent_buffer *eb;
1055 eb = read_tree_block(fs_info->extent_root,
1060 } else if (!extent_buffer_uptodate(eb)) {
1061 free_extent_buffer(eb);
1065 btrfs_tree_read_lock(eb);
1066 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
1067 ret = find_extent_in_eb(eb, bytenr,
1068 *extent_item_pos, &eie);
1069 btrfs_tree_read_unlock_blocking(eb);
1070 free_extent_buffer(eb);
1073 ref->inode_list = eie;
1075 ret = ulist_add_merge_ptr(refs, ref->parent,
1077 (void **)&eie, GFP_NOFS);
1080 if (!ret && extent_item_pos) {
1082 * we've recorded that parent, so we must extend
1083 * its inode list here
1088 eie->next = ref->inode_list;
1092 list_del(&ref->list);
1093 kmem_cache_free(btrfs_prelim_ref_cache, ref);
1097 btrfs_free_path(path);
1098 while (!list_empty(&prefs)) {
1099 ref = list_first_entry(&prefs, struct __prelim_ref, list);
1100 list_del(&ref->list);
1101 kmem_cache_free(btrfs_prelim_ref_cache, ref);
1103 while (!list_empty(&prefs_delayed)) {
1104 ref = list_first_entry(&prefs_delayed, struct __prelim_ref,
1106 list_del(&ref->list);
1107 kmem_cache_free(btrfs_prelim_ref_cache, ref);
1110 free_inode_elem_list(eie);
1114 static void free_leaf_list(struct ulist *blocks)
1116 struct ulist_node *node = NULL;
1117 struct extent_inode_elem *eie;
1118 struct ulist_iterator uiter;
1120 ULIST_ITER_INIT(&uiter);
1121 while ((node = ulist_next(blocks, &uiter))) {
1124 eie = (struct extent_inode_elem *)(uintptr_t)node->aux;
1125 free_inode_elem_list(eie);
1133 * Finds all leafs with a reference to the specified combination of bytenr and
1134 * offset. key_list_head will point to a list of corresponding keys (caller must
1135 * free each list element). The leafs will be stored in the leafs ulist, which
1136 * must be freed with ulist_free.
1138 * returns 0 on success, <0 on error
1140 static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
1141 struct btrfs_fs_info *fs_info, u64 bytenr,
1142 u64 time_seq, struct ulist **leafs,
1143 const u64 *extent_item_pos)
1147 *leafs = ulist_alloc(GFP_NOFS);
1151 ret = find_parent_nodes(trans, fs_info, bytenr,
1152 time_seq, *leafs, NULL, extent_item_pos, 0, 0);
1153 if (ret < 0 && ret != -ENOENT) {
1154 free_leaf_list(*leafs);
1162 * walk all backrefs for a given extent to find all roots that reference this
1163 * extent. Walking a backref means finding all extents that reference this
1164 * extent and in turn walk the backrefs of those, too. Naturally this is a
1165 * recursive process, but here it is implemented in an iterative fashion: We
1166 * find all referencing extents for the extent in question and put them on a
1167 * list. In turn, we find all referencing extents for those, further appending
1168 * to the list. The way we iterate the list allows adding more elements after
1169 * the current while iterating. The process stops when we reach the end of the
1170 * list. Found roots are added to the roots list.
1172 * returns 0 on success, < 0 on error.
1174 static int __btrfs_find_all_roots(struct btrfs_trans_handle *trans,
1175 struct btrfs_fs_info *fs_info, u64 bytenr,
1176 u64 time_seq, struct ulist **roots)
1179 struct ulist_node *node = NULL;
1180 struct ulist_iterator uiter;
1183 tmp = ulist_alloc(GFP_NOFS);
1186 *roots = ulist_alloc(GFP_NOFS);
1192 ULIST_ITER_INIT(&uiter);
1194 ret = find_parent_nodes(trans, fs_info, bytenr,
1195 time_seq, tmp, *roots, NULL, 0, 0);
1196 if (ret < 0 && ret != -ENOENT) {
1201 node = ulist_next(tmp, &uiter);
1212 int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
1213 struct btrfs_fs_info *fs_info, u64 bytenr,
1214 u64 time_seq, struct ulist **roots)
1219 down_read(&fs_info->commit_root_sem);
1220 ret = __btrfs_find_all_roots(trans, fs_info, bytenr, time_seq, roots);
1222 up_read(&fs_info->commit_root_sem);
1227 * btrfs_check_shared - tell us whether an extent is shared
1229 * @trans: optional trans handle
1231 * btrfs_check_shared uses the backref walking code but will short
1232 * circuit as soon as it finds a root or inode that doesn't match the
1233 * one passed in. This provides a significant performance benefit for
1234 * callers (such as fiemap) which want to know whether the extent is
1235 * shared but do not need a ref count.
1237 * Return: 0 if extent is not shared, 1 if it is shared, < 0 on error.
1239 int btrfs_check_shared(struct btrfs_trans_handle *trans,
1240 struct btrfs_fs_info *fs_info, u64 root_objectid,
1241 u64 inum, u64 bytenr)
1243 struct ulist *tmp = NULL;
1244 struct ulist *roots = NULL;
1245 struct ulist_iterator uiter;
1246 struct ulist_node *node;
1247 struct seq_list elem = SEQ_LIST_INIT(elem);
1250 tmp = ulist_alloc(GFP_NOFS);
1251 roots = ulist_alloc(GFP_NOFS);
1252 if (!tmp || !roots) {
1259 btrfs_get_tree_mod_seq(fs_info, &elem);
1261 down_read(&fs_info->commit_root_sem);
1262 ULIST_ITER_INIT(&uiter);
1264 ret = find_parent_nodes(trans, fs_info, bytenr, elem.seq, tmp,
1265 roots, NULL, root_objectid, inum);
1266 if (ret == BACKREF_FOUND_SHARED) {
1267 /* this is the only condition under which we return 1 */
1271 if (ret < 0 && ret != -ENOENT)
1274 node = ulist_next(tmp, &uiter);
1281 btrfs_put_tree_mod_seq(fs_info, &elem);
1283 up_read(&fs_info->commit_root_sem);
1289 int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
1290 u64 start_off, struct btrfs_path *path,
1291 struct btrfs_inode_extref **ret_extref,
1295 struct btrfs_key key;
1296 struct btrfs_key found_key;
1297 struct btrfs_inode_extref *extref;
1298 struct extent_buffer *leaf;
1301 key.objectid = inode_objectid;
1302 key.type = BTRFS_INODE_EXTREF_KEY;
1303 key.offset = start_off;
1305 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1310 leaf = path->nodes[0];
1311 slot = path->slots[0];
1312 if (slot >= btrfs_header_nritems(leaf)) {
1314 * If the item at offset is not found,
1315 * btrfs_search_slot will point us to the slot
1316 * where it should be inserted. In our case
1317 * that will be the slot directly before the
1318 * next INODE_REF_KEY_V2 item. In the case
1319 * that we're pointing to the last slot in a
1320 * leaf, we must move one leaf over.
1322 ret = btrfs_next_leaf(root, path);
1331 btrfs_item_key_to_cpu(leaf, &found_key, slot);
1334 * Check that we're still looking at an extended ref key for
1335 * this particular objectid. If we have different
1336 * objectid or type then there are no more to be found
1337 * in the tree and we can exit.
1340 if (found_key.objectid != inode_objectid)
1342 if (found_key.type != BTRFS_INODE_EXTREF_KEY)
1346 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
1347 extref = (struct btrfs_inode_extref *)ptr;
1348 *ret_extref = extref;
1350 *found_off = found_key.offset;
1358 * this iterates to turn a name (from iref/extref) into a full filesystem path.
1359 * Elements of the path are separated by '/' and the path is guaranteed to be
1360 * 0-terminated. the path is only given within the current file system.
1361 * Therefore, it never starts with a '/'. the caller is responsible to provide
1362 * "size" bytes in "dest". the dest buffer will be filled backwards. finally,
1363 * the start point of the resulting string is returned. this pointer is within
1365 * in case the path buffer would overflow, the pointer is decremented further
1366 * as if output was written to the buffer, though no more output is actually
1367 * generated. that way, the caller can determine how much space would be
1368 * required for the path to fit into the buffer. in that case, the returned
1369 * value will be smaller than dest. callers must check this!
1371 char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
1372 u32 name_len, unsigned long name_off,
1373 struct extent_buffer *eb_in, u64 parent,
1374 char *dest, u32 size)
1379 s64 bytes_left = ((s64)size) - 1;
1380 struct extent_buffer *eb = eb_in;
1381 struct btrfs_key found_key;
1382 int leave_spinning = path->leave_spinning;
1383 struct btrfs_inode_ref *iref;
1385 if (bytes_left >= 0)
1386 dest[bytes_left] = '\0';
1388 path->leave_spinning = 1;
1390 bytes_left -= name_len;
1391 if (bytes_left >= 0)
1392 read_extent_buffer(eb, dest + bytes_left,
1393 name_off, name_len);
1395 btrfs_tree_read_unlock_blocking(eb);
1396 free_extent_buffer(eb);
1398 ret = btrfs_find_item(fs_root, path, parent, 0,
1399 BTRFS_INODE_REF_KEY, &found_key);
1405 next_inum = found_key.offset;
1407 /* regular exit ahead */
1408 if (parent == next_inum)
1411 slot = path->slots[0];
1412 eb = path->nodes[0];
1413 /* make sure we can use eb after releasing the path */
1415 atomic_inc(&eb->refs);
1416 btrfs_tree_read_lock(eb);
1417 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
1419 btrfs_release_path(path);
1420 iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
1422 name_len = btrfs_inode_ref_name_len(eb, iref);
1423 name_off = (unsigned long)(iref + 1);
1427 if (bytes_left >= 0)
1428 dest[bytes_left] = '/';
1431 btrfs_release_path(path);
1432 path->leave_spinning = leave_spinning;
1435 return ERR_PTR(ret);
1437 return dest + bytes_left;
1441 * this makes the path point to (logical EXTENT_ITEM *)
1442 * returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for
1443 * tree blocks and <0 on error.
1445 int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
1446 struct btrfs_path *path, struct btrfs_key *found_key,
1453 struct extent_buffer *eb;
1454 struct btrfs_extent_item *ei;
1455 struct btrfs_key key;
1457 if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
1458 key.type = BTRFS_METADATA_ITEM_KEY;
1460 key.type = BTRFS_EXTENT_ITEM_KEY;
1461 key.objectid = logical;
1462 key.offset = (u64)-1;
1464 ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
1468 ret = btrfs_previous_extent_item(fs_info->extent_root, path, 0);
1474 btrfs_item_key_to_cpu(path->nodes[0], found_key, path->slots[0]);
1475 if (found_key->type == BTRFS_METADATA_ITEM_KEY)
1476 size = fs_info->extent_root->nodesize;
1477 else if (found_key->type == BTRFS_EXTENT_ITEM_KEY)
1478 size = found_key->offset;
1480 if (found_key->objectid > logical ||
1481 found_key->objectid + size <= logical) {
1482 pr_debug("logical %llu is not within any extent\n", logical);
1486 eb = path->nodes[0];
1487 item_size = btrfs_item_size_nr(eb, path->slots[0]);
1488 BUG_ON(item_size < sizeof(*ei));
1490 ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
1491 flags = btrfs_extent_flags(eb, ei);
1493 pr_debug("logical %llu is at position %llu within the extent (%llu "
1494 "EXTENT_ITEM %llu) flags %#llx size %u\n",
1495 logical, logical - found_key->objectid, found_key->objectid,
1496 found_key->offset, flags, item_size);
1498 WARN_ON(!flags_ret);
1500 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
1501 *flags_ret = BTRFS_EXTENT_FLAG_TREE_BLOCK;
1502 else if (flags & BTRFS_EXTENT_FLAG_DATA)
1503 *flags_ret = BTRFS_EXTENT_FLAG_DATA;
1513 * helper function to iterate extent inline refs. ptr must point to a 0 value
1514 * for the first call and may be modified. it is used to track state.
1515 * if more refs exist, 0 is returned and the next call to
1516 * __get_extent_inline_ref must pass the modified ptr parameter to get the
1517 * next ref. after the last ref was processed, 1 is returned.
1518 * returns <0 on error
1520 static int __get_extent_inline_ref(unsigned long *ptr, struct extent_buffer *eb,
1521 struct btrfs_key *key,
1522 struct btrfs_extent_item *ei, u32 item_size,
1523 struct btrfs_extent_inline_ref **out_eiref,
1528 struct btrfs_tree_block_info *info;
1532 flags = btrfs_extent_flags(eb, ei);
1533 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1534 if (key->type == BTRFS_METADATA_ITEM_KEY) {
1535 /* a skinny metadata extent */
1537 (struct btrfs_extent_inline_ref *)(ei + 1);
1539 WARN_ON(key->type != BTRFS_EXTENT_ITEM_KEY);
1540 info = (struct btrfs_tree_block_info *)(ei + 1);
1542 (struct btrfs_extent_inline_ref *)(info + 1);
1545 *out_eiref = (struct btrfs_extent_inline_ref *)(ei + 1);
1547 *ptr = (unsigned long)*out_eiref;
1548 if ((unsigned long)(*ptr) >= (unsigned long)ei + item_size)
1552 end = (unsigned long)ei + item_size;
1553 *out_eiref = (struct btrfs_extent_inline_ref *)(*ptr);
1554 *out_type = btrfs_extent_inline_ref_type(eb, *out_eiref);
1556 *ptr += btrfs_extent_inline_ref_size(*out_type);
1557 WARN_ON(*ptr > end);
1559 return 1; /* last */
1565 * reads the tree block backref for an extent. tree level and root are returned
1566 * through out_level and out_root. ptr must point to a 0 value for the first
1567 * call and may be modified (see __get_extent_inline_ref comment).
1568 * returns 0 if data was provided, 1 if there was no more data to provide or
1571 int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
1572 struct btrfs_key *key, struct btrfs_extent_item *ei,
1573 u32 item_size, u64 *out_root, u8 *out_level)
1577 struct btrfs_extent_inline_ref *eiref;
1579 if (*ptr == (unsigned long)-1)
1583 ret = __get_extent_inline_ref(ptr, eb, key, ei, item_size,
1588 if (type == BTRFS_TREE_BLOCK_REF_KEY ||
1589 type == BTRFS_SHARED_BLOCK_REF_KEY)
1596 /* we can treat both ref types equally here */
1597 *out_root = btrfs_extent_inline_ref_offset(eb, eiref);
1599 if (key->type == BTRFS_EXTENT_ITEM_KEY) {
1600 struct btrfs_tree_block_info *info;
1602 info = (struct btrfs_tree_block_info *)(ei + 1);
1603 *out_level = btrfs_tree_block_level(eb, info);
1605 ASSERT(key->type == BTRFS_METADATA_ITEM_KEY);
1606 *out_level = (u8)key->offset;
1610 *ptr = (unsigned long)-1;
1615 static int iterate_leaf_refs(struct extent_inode_elem *inode_list,
1616 u64 root, u64 extent_item_objectid,
1617 iterate_extent_inodes_t *iterate, void *ctx)
1619 struct extent_inode_elem *eie;
1622 for (eie = inode_list; eie; eie = eie->next) {
1623 pr_debug("ref for %llu resolved, key (%llu EXTEND_DATA %llu), "
1624 "root %llu\n", extent_item_objectid,
1625 eie->inum, eie->offset, root);
1626 ret = iterate(eie->inum, eie->offset, root, ctx);
1628 pr_debug("stopping iteration for %llu due to ret=%d\n",
1629 extent_item_objectid, ret);
1638 * calls iterate() for every inode that references the extent identified by
1639 * the given parameters.
1640 * when the iterator function returns a non-zero value, iteration stops.
1642 int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
1643 u64 extent_item_objectid, u64 extent_item_pos,
1644 int search_commit_root,
1645 iterate_extent_inodes_t *iterate, void *ctx)
1648 struct btrfs_trans_handle *trans = NULL;
1649 struct ulist *refs = NULL;
1650 struct ulist *roots = NULL;
1651 struct ulist_node *ref_node = NULL;
1652 struct ulist_node *root_node = NULL;
1653 struct seq_list tree_mod_seq_elem = SEQ_LIST_INIT(tree_mod_seq_elem);
1654 struct ulist_iterator ref_uiter;
1655 struct ulist_iterator root_uiter;
1657 pr_debug("resolving all inodes for extent %llu\n",
1658 extent_item_objectid);
1660 if (!search_commit_root) {
1661 trans = btrfs_join_transaction(fs_info->extent_root);
1663 return PTR_ERR(trans);
1664 btrfs_get_tree_mod_seq(fs_info, &tree_mod_seq_elem);
1666 down_read(&fs_info->commit_root_sem);
1669 ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid,
1670 tree_mod_seq_elem.seq, &refs,
1675 ULIST_ITER_INIT(&ref_uiter);
1676 while (!ret && (ref_node = ulist_next(refs, &ref_uiter))) {
1677 ret = __btrfs_find_all_roots(trans, fs_info, ref_node->val,
1678 tree_mod_seq_elem.seq, &roots);
1681 ULIST_ITER_INIT(&root_uiter);
1682 while (!ret && (root_node = ulist_next(roots, &root_uiter))) {
1683 pr_debug("root %llu references leaf %llu, data list "
1684 "%#llx\n", root_node->val, ref_node->val,
1686 ret = iterate_leaf_refs((struct extent_inode_elem *)
1687 (uintptr_t)ref_node->aux,
1689 extent_item_objectid,
1695 free_leaf_list(refs);
1697 if (!search_commit_root) {
1698 btrfs_put_tree_mod_seq(fs_info, &tree_mod_seq_elem);
1699 btrfs_end_transaction(trans, fs_info->extent_root);
1701 up_read(&fs_info->commit_root_sem);
1707 int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
1708 struct btrfs_path *path,
1709 iterate_extent_inodes_t *iterate, void *ctx)
1712 u64 extent_item_pos;
1714 struct btrfs_key found_key;
1715 int search_commit_root = path->search_commit_root;
1717 ret = extent_from_logical(fs_info, logical, path, &found_key, &flags);
1718 btrfs_release_path(path);
1721 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
1724 extent_item_pos = logical - found_key.objectid;
1725 ret = iterate_extent_inodes(fs_info, found_key.objectid,
1726 extent_item_pos, search_commit_root,
1732 typedef int (iterate_irefs_t)(u64 parent, u32 name_len, unsigned long name_off,
1733 struct extent_buffer *eb, void *ctx);
1735 static int iterate_inode_refs(u64 inum, struct btrfs_root *fs_root,
1736 struct btrfs_path *path,
1737 iterate_irefs_t *iterate, void *ctx)
1746 struct extent_buffer *eb;
1747 struct btrfs_item *item;
1748 struct btrfs_inode_ref *iref;
1749 struct btrfs_key found_key;
1752 ret = btrfs_find_item(fs_root, path, inum,
1753 parent ? parent + 1 : 0, BTRFS_INODE_REF_KEY,
1759 ret = found ? 0 : -ENOENT;
1764 parent = found_key.offset;
1765 slot = path->slots[0];
1766 eb = btrfs_clone_extent_buffer(path->nodes[0]);
1771 extent_buffer_get(eb);
1772 btrfs_tree_read_lock(eb);
1773 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
1774 btrfs_release_path(path);
1776 item = btrfs_item_nr(slot);
1777 iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
1779 for (cur = 0; cur < btrfs_item_size(eb, item); cur += len) {
1780 name_len = btrfs_inode_ref_name_len(eb, iref);
1781 /* path must be released before calling iterate()! */
1782 pr_debug("following ref at offset %u for inode %llu in "
1783 "tree %llu\n", cur, found_key.objectid,
1785 ret = iterate(parent, name_len,
1786 (unsigned long)(iref + 1), eb, ctx);
1789 len = sizeof(*iref) + name_len;
1790 iref = (struct btrfs_inode_ref *)((char *)iref + len);
1792 btrfs_tree_read_unlock_blocking(eb);
1793 free_extent_buffer(eb);
1796 btrfs_release_path(path);
1801 static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root,
1802 struct btrfs_path *path,
1803 iterate_irefs_t *iterate, void *ctx)
1810 struct extent_buffer *eb;
1811 struct btrfs_inode_extref *extref;
1812 struct extent_buffer *leaf;
1818 ret = btrfs_find_one_extref(fs_root, inum, offset, path, &extref,
1823 ret = found ? 0 : -ENOENT;
1828 slot = path->slots[0];
1829 eb = btrfs_clone_extent_buffer(path->nodes[0]);
1834 extent_buffer_get(eb);
1836 btrfs_tree_read_lock(eb);
1837 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
1838 btrfs_release_path(path);
1840 leaf = path->nodes[0];
1841 item_size = btrfs_item_size_nr(leaf, slot);
1842 ptr = btrfs_item_ptr_offset(leaf, slot);
1845 while (cur_offset < item_size) {
1848 extref = (struct btrfs_inode_extref *)(ptr + cur_offset);
1849 parent = btrfs_inode_extref_parent(eb, extref);
1850 name_len = btrfs_inode_extref_name_len(eb, extref);
1851 ret = iterate(parent, name_len,
1852 (unsigned long)&extref->name, eb, ctx);
1856 cur_offset += btrfs_inode_extref_name_len(leaf, extref);
1857 cur_offset += sizeof(*extref);
1859 btrfs_tree_read_unlock_blocking(eb);
1860 free_extent_buffer(eb);
1865 btrfs_release_path(path);
1870 static int iterate_irefs(u64 inum, struct btrfs_root *fs_root,
1871 struct btrfs_path *path, iterate_irefs_t *iterate,
1877 ret = iterate_inode_refs(inum, fs_root, path, iterate, ctx);
1880 else if (ret != -ENOENT)
1883 ret = iterate_inode_extrefs(inum, fs_root, path, iterate, ctx);
1884 if (ret == -ENOENT && found_refs)
1891 * returns 0 if the path could be dumped (probably truncated)
1892 * returns <0 in case of an error
1894 static int inode_to_path(u64 inum, u32 name_len, unsigned long name_off,
1895 struct extent_buffer *eb, void *ctx)
1897 struct inode_fs_paths *ipath = ctx;
1900 int i = ipath->fspath->elem_cnt;
1901 const int s_ptr = sizeof(char *);
1904 bytes_left = ipath->fspath->bytes_left > s_ptr ?
1905 ipath->fspath->bytes_left - s_ptr : 0;
1907 fspath_min = (char *)ipath->fspath->val + (i + 1) * s_ptr;
1908 fspath = btrfs_ref_to_path(ipath->fs_root, ipath->btrfs_path, name_len,
1909 name_off, eb, inum, fspath_min, bytes_left);
1911 return PTR_ERR(fspath);
1913 if (fspath > fspath_min) {
1914 ipath->fspath->val[i] = (u64)(unsigned long)fspath;
1915 ++ipath->fspath->elem_cnt;
1916 ipath->fspath->bytes_left = fspath - fspath_min;
1918 ++ipath->fspath->elem_missed;
1919 ipath->fspath->bytes_missing += fspath_min - fspath;
1920 ipath->fspath->bytes_left = 0;
1927 * this dumps all file system paths to the inode into the ipath struct, provided
1928 * is has been created large enough. each path is zero-terminated and accessed
1929 * from ipath->fspath->val[i].
1930 * when it returns, there are ipath->fspath->elem_cnt number of paths available
1931 * in ipath->fspath->val[]. when the allocated space wasn't sufficient, the
1932 * number of missed paths in recored in ipath->fspath->elem_missed, otherwise,
1933 * it's zero. ipath->fspath->bytes_missing holds the number of bytes that would
1934 * have been needed to return all paths.
1936 int paths_from_inode(u64 inum, struct inode_fs_paths *ipath)
1938 return iterate_irefs(inum, ipath->fs_root, ipath->btrfs_path,
1939 inode_to_path, ipath);
1942 struct btrfs_data_container *init_data_container(u32 total_bytes)
1944 struct btrfs_data_container *data;
1947 alloc_bytes = max_t(size_t, total_bytes, sizeof(*data));
1948 data = vmalloc(alloc_bytes);
1950 return ERR_PTR(-ENOMEM);
1952 if (total_bytes >= sizeof(*data)) {
1953 data->bytes_left = total_bytes - sizeof(*data);
1954 data->bytes_missing = 0;
1956 data->bytes_missing = sizeof(*data) - total_bytes;
1957 data->bytes_left = 0;
1961 data->elem_missed = 0;
1967 * allocates space to return multiple file system paths for an inode.
1968 * total_bytes to allocate are passed, note that space usable for actual path
1969 * information will be total_bytes - sizeof(struct inode_fs_paths).
1970 * the returned pointer must be freed with free_ipath() in the end.
1972 struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root,
1973 struct btrfs_path *path)
1975 struct inode_fs_paths *ifp;
1976 struct btrfs_data_container *fspath;
1978 fspath = init_data_container(total_bytes);
1980 return (void *)fspath;
1982 ifp = kmalloc(sizeof(*ifp), GFP_NOFS);
1985 return ERR_PTR(-ENOMEM);
1988 ifp->btrfs_path = path;
1989 ifp->fspath = fspath;
1990 ifp->fs_root = fs_root;
1995 void free_ipath(struct inode_fs_paths *ipath)
1999 vfree(ipath->fspath);