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>
20 #include <linux/rbtree.h>
25 #include "transaction.h"
26 #include "delayed-ref.h"
29 /* Just an arbitrary number so we can be sure this happened */
30 #define BACKREF_FOUND_SHARED 6
32 struct extent_inode_elem {
35 struct extent_inode_elem *next;
39 * ref_root is used as the root of the ref tree that hold a collection
40 * of unique references.
43 struct rb_root rb_root;
46 * The unique_refs represents the number of ref_nodes with a positive
47 * count stored in the tree. Even if a ref_node (the count is greater
48 * than one) is added, the unique_refs will only increase by one.
50 unsigned int unique_refs;
53 /* ref_node is used to store a unique reference to the ref tree. */
55 struct rb_node rb_node;
57 /* For NORMAL_REF, otherwise all these fields should be set to 0 */
62 /* For SHARED_REF, otherwise parent field should be set to 0 */
65 /* Ref to the ref_mod of btrfs_delayed_ref_node */
69 /* Dynamically allocate and initialize a ref_root */
70 static struct ref_root *ref_root_alloc(void)
72 struct ref_root *ref_tree;
74 ref_tree = kmalloc(sizeof(*ref_tree), GFP_NOFS);
78 ref_tree->rb_root = RB_ROOT;
79 ref_tree->unique_refs = 0;
84 /* Free all nodes in the ref tree, and reinit ref_root */
85 static void ref_root_fini(struct ref_root *ref_tree)
87 struct ref_node *node;
90 while ((next = rb_first(&ref_tree->rb_root)) != NULL) {
91 node = rb_entry(next, struct ref_node, rb_node);
92 rb_erase(next, &ref_tree->rb_root);
96 ref_tree->rb_root = RB_ROOT;
97 ref_tree->unique_refs = 0;
100 static void ref_root_free(struct ref_root *ref_tree)
105 ref_root_fini(ref_tree);
110 * Compare ref_node with (root_id, object_id, offset, parent)
112 * The function compares two ref_node a and b. It returns an integer less
113 * than, equal to, or greater than zero , respectively, to be less than, to
114 * equal, or be greater than b.
116 static int ref_node_cmp(struct ref_node *a, struct ref_node *b)
118 if (a->root_id < b->root_id)
120 else if (a->root_id > b->root_id)
123 if (a->object_id < b->object_id)
125 else if (a->object_id > b->object_id)
128 if (a->offset < b->offset)
130 else if (a->offset > b->offset)
133 if (a->parent < b->parent)
135 else if (a->parent > b->parent)
142 * Search ref_node with (root_id, object_id, offset, parent) in the tree
144 * if found, the pointer of the ref_node will be returned;
145 * if not found, NULL will be returned and pos will point to the rb_node for
146 * insert, pos_parent will point to pos'parent for insert;
148 static struct ref_node *__ref_tree_search(struct ref_root *ref_tree,
149 struct rb_node ***pos,
150 struct rb_node **pos_parent,
151 u64 root_id, u64 object_id,
152 u64 offset, u64 parent)
154 struct ref_node *cur = NULL;
155 struct ref_node entry;
158 entry.root_id = root_id;
159 entry.object_id = object_id;
160 entry.offset = offset;
161 entry.parent = parent;
163 *pos = &ref_tree->rb_root.rb_node;
167 cur = rb_entry(*pos_parent, struct ref_node, rb_node);
169 ret = ref_node_cmp(cur, &entry);
171 *pos = &(**pos)->rb_left;
173 *pos = &(**pos)->rb_right;
182 * Insert a ref_node to the ref tree
183 * @pos used for specifiy the position to insert
184 * @pos_parent for specifiy pos's parent
187 * ref_node already exists, return -EEXIST;
189 static int ref_tree_insert(struct ref_root *ref_tree, struct rb_node **pos,
190 struct rb_node *pos_parent, struct ref_node *ins)
192 struct rb_node **p = NULL;
193 struct rb_node *parent = NULL;
194 struct ref_node *cur = NULL;
197 cur = __ref_tree_search(ref_tree, &p, &parent, ins->root_id,
198 ins->object_id, ins->offset,
207 rb_link_node(&ins->rb_node, parent, p);
208 rb_insert_color(&ins->rb_node, &ref_tree->rb_root);
213 /* Erase and free ref_node, caller should update ref_root->unique_refs */
214 static void ref_tree_remove(struct ref_root *ref_tree, struct ref_node *node)
216 rb_erase(&node->rb_node, &ref_tree->rb_root);
221 * Update ref_root->unique_refs
223 * Call __ref_tree_search
224 * 1. if ref_node doesn't exist, ref_tree_insert this node, and update
225 * ref_root->unique_refs:
226 * if ref_node->ref_mod > 0, ref_root->unique_refs++;
227 * if ref_node->ref_mod < 0, do noting;
229 * 2. if ref_node is found, then get origin ref_node->ref_mod, and update
231 * if ref_node->ref_mod is equal to 0,then call ref_tree_remove
233 * according to origin_mod and new_mod, update ref_root->items
234 * +----------------+--------------+-------------+
235 * | |new_count <= 0|new_count > 0|
236 * +----------------+--------------+-------------+
237 * |origin_count < 0| 0 | 1 |
238 * +----------------+--------------+-------------+
239 * |origin_count > 0| -1 | 0 |
240 * +----------------+--------------+-------------+
242 * In case of allocation failure, -ENOMEM is returned and the ref_tree stays
246 static int ref_tree_add(struct ref_root *ref_tree, u64 root_id, u64 object_id,
247 u64 offset, u64 parent, int count)
249 struct ref_node *node = NULL;
250 struct rb_node **pos = NULL;
251 struct rb_node *pos_parent = NULL;
258 node = __ref_tree_search(ref_tree, &pos, &pos_parent, root_id,
259 object_id, offset, parent);
261 node = kmalloc(sizeof(*node), GFP_NOFS);
265 node->root_id = root_id;
266 node->object_id = object_id;
267 node->offset = offset;
268 node->parent = parent;
269 node->ref_mod = count;
271 ret = ref_tree_insert(ref_tree, pos, pos_parent, node);
278 ref_tree->unique_refs += node->ref_mod > 0 ? 1 : 0;
283 origin_count = node->ref_mod;
284 node->ref_mod += count;
286 if (node->ref_mod > 0)
287 ref_tree->unique_refs += origin_count > 0 ? 0 : 1;
288 else if (node->ref_mod <= 0)
289 ref_tree->unique_refs += origin_count > 0 ? -1 : 0;
292 ref_tree_remove(ref_tree, node);
297 static int check_extent_in_eb(struct btrfs_key *key, struct extent_buffer *eb,
298 struct btrfs_file_extent_item *fi,
300 struct extent_inode_elem **eie)
303 struct extent_inode_elem *e;
305 if (!btrfs_file_extent_compression(eb, fi) &&
306 !btrfs_file_extent_encryption(eb, fi) &&
307 !btrfs_file_extent_other_encoding(eb, fi)) {
311 data_offset = btrfs_file_extent_offset(eb, fi);
312 data_len = btrfs_file_extent_num_bytes(eb, fi);
314 if (extent_item_pos < data_offset ||
315 extent_item_pos >= data_offset + data_len)
317 offset = extent_item_pos - data_offset;
320 e = kmalloc(sizeof(*e), GFP_NOFS);
325 e->inum = key->objectid;
326 e->offset = key->offset + offset;
332 static void free_inode_elem_list(struct extent_inode_elem *eie)
334 struct extent_inode_elem *eie_next;
336 for (; eie; eie = eie_next) {
337 eie_next = eie->next;
342 static int find_extent_in_eb(struct extent_buffer *eb, u64 wanted_disk_byte,
344 struct extent_inode_elem **eie)
347 struct btrfs_key key;
348 struct btrfs_file_extent_item *fi;
355 * from the shared data ref, we only have the leaf but we need
356 * the key. thus, we must look into all items and see that we
357 * find one (some) with a reference to our extent item.
359 nritems = btrfs_header_nritems(eb);
360 for (slot = 0; slot < nritems; ++slot) {
361 btrfs_item_key_to_cpu(eb, &key, slot);
362 if (key.type != BTRFS_EXTENT_DATA_KEY)
364 fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
365 extent_type = btrfs_file_extent_type(eb, fi);
366 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
368 /* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */
369 disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
370 if (disk_byte != wanted_disk_byte)
373 ret = check_extent_in_eb(&key, eb, fi, extent_item_pos, eie);
382 * this structure records all encountered refs on the way up to the root
384 struct __prelim_ref {
385 struct list_head list;
387 struct btrfs_key key_for_search;
390 struct extent_inode_elem *inode_list;
392 u64 wanted_disk_byte;
395 static struct kmem_cache *btrfs_prelim_ref_cache;
397 int __init btrfs_prelim_ref_init(void)
399 btrfs_prelim_ref_cache = kmem_cache_create("btrfs_prelim_ref",
400 sizeof(struct __prelim_ref),
404 if (!btrfs_prelim_ref_cache)
409 void btrfs_prelim_ref_exit(void)
411 kmem_cache_destroy(btrfs_prelim_ref_cache);
415 * the rules for all callers of this function are:
416 * - obtaining the parent is the goal
417 * - if you add a key, you must know that it is a correct key
418 * - if you cannot add the parent or a correct key, then we will look into the
419 * block later to set a correct key
423 * backref type | shared | indirect | shared | indirect
424 * information | tree | tree | data | data
425 * --------------------+--------+----------+--------+----------
426 * parent logical | y | - | - | -
427 * key to resolve | - | y | y | y
428 * tree block logical | - | - | - | -
429 * root for resolving | y | y | y | y
431 * - column 1: we've the parent -> done
432 * - column 2, 3, 4: we use the key to find the parent
434 * on disk refs (inline or keyed)
435 * ==============================
436 * backref type | shared | indirect | shared | indirect
437 * information | tree | tree | data | data
438 * --------------------+--------+----------+--------+----------
439 * parent logical | y | - | y | -
440 * key to resolve | - | - | - | y
441 * tree block logical | y | y | y | y
442 * root for resolving | - | y | y | y
444 * - column 1, 3: we've the parent -> done
445 * - column 2: we take the first key from the block to find the parent
446 * (see __add_missing_keys)
447 * - column 4: we use the key to find the parent
449 * additional information that's available but not required to find the parent
450 * block might help in merging entries to gain some speed.
453 static int __add_prelim_ref(struct list_head *head, u64 root_id,
454 struct btrfs_key *key, int level,
455 u64 parent, u64 wanted_disk_byte, int count,
458 struct __prelim_ref *ref;
460 if (root_id == BTRFS_DATA_RELOC_TREE_OBJECTID)
463 ref = kmem_cache_alloc(btrfs_prelim_ref_cache, gfp_mask);
467 ref->root_id = root_id;
469 ref->key_for_search = *key;
471 * We can often find data backrefs with an offset that is too
472 * large (>= LLONG_MAX, maximum allowed file offset) due to
473 * underflows when subtracting a file's offset with the data
474 * offset of its corresponding extent data item. This can
475 * happen for example in the clone ioctl.
476 * So if we detect such case we set the search key's offset to
477 * zero to make sure we will find the matching file extent item
478 * at add_all_parents(), otherwise we will miss it because the
479 * offset taken form the backref is much larger then the offset
480 * of the file extent item. This can make us scan a very large
481 * number of file extent items, but at least it will not make
483 * This is an ugly workaround for a behaviour that should have
484 * never existed, but it does and a fix for the clone ioctl
485 * would touch a lot of places, cause backwards incompatibility
486 * and would not fix the problem for extents cloned with older
489 if (ref->key_for_search.type == BTRFS_EXTENT_DATA_KEY &&
490 ref->key_for_search.offset >= LLONG_MAX)
491 ref->key_for_search.offset = 0;
493 memset(&ref->key_for_search, 0, sizeof(ref->key_for_search));
496 ref->inode_list = NULL;
499 ref->parent = parent;
500 ref->wanted_disk_byte = wanted_disk_byte;
501 list_add_tail(&ref->list, head);
506 static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
507 struct ulist *parents, struct __prelim_ref *ref,
508 int level, u64 time_seq, const u64 *extent_item_pos,
513 struct extent_buffer *eb;
514 struct btrfs_key key;
515 struct btrfs_key *key_for_search = &ref->key_for_search;
516 struct btrfs_file_extent_item *fi;
517 struct extent_inode_elem *eie = NULL, *old = NULL;
519 u64 wanted_disk_byte = ref->wanted_disk_byte;
523 eb = path->nodes[level];
524 ret = ulist_add(parents, eb->start, 0, GFP_NOFS);
531 * We normally enter this function with the path already pointing to
532 * the first item to check. But sometimes, we may enter it with
533 * slot==nritems. In that case, go to the next leaf before we continue.
535 if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
536 if (time_seq == (u64)-1)
537 ret = btrfs_next_leaf(root, path);
539 ret = btrfs_next_old_leaf(root, path, time_seq);
542 while (!ret && count < total_refs) {
544 slot = path->slots[0];
546 btrfs_item_key_to_cpu(eb, &key, slot);
548 if (key.objectid != key_for_search->objectid ||
549 key.type != BTRFS_EXTENT_DATA_KEY)
552 fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
553 disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
555 if (disk_byte == wanted_disk_byte) {
559 if (extent_item_pos) {
560 ret = check_extent_in_eb(&key, eb, fi,
568 ret = ulist_add_merge_ptr(parents, eb->start,
569 eie, (void **)&old, GFP_NOFS);
572 if (!ret && extent_item_pos) {
580 if (time_seq == (u64)-1)
581 ret = btrfs_next_item(root, path);
583 ret = btrfs_next_old_item(root, path, time_seq);
589 free_inode_elem_list(eie);
594 * resolve an indirect backref in the form (root_id, key, level)
595 * to a logical address
597 static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info,
598 struct btrfs_path *path, u64 time_seq,
599 struct __prelim_ref *ref,
600 struct ulist *parents,
601 const u64 *extent_item_pos, u64 total_refs)
603 struct btrfs_root *root;
604 struct btrfs_key root_key;
605 struct extent_buffer *eb;
608 int level = ref->level;
611 root_key.objectid = ref->root_id;
612 root_key.type = BTRFS_ROOT_ITEM_KEY;
613 root_key.offset = (u64)-1;
615 index = srcu_read_lock(&fs_info->subvol_srcu);
617 root = btrfs_get_fs_root(fs_info, &root_key, false);
619 srcu_read_unlock(&fs_info->subvol_srcu, index);
624 if (btrfs_is_testing(fs_info)) {
625 srcu_read_unlock(&fs_info->subvol_srcu, index);
630 if (path->search_commit_root)
631 root_level = btrfs_header_level(root->commit_root);
632 else if (time_seq == (u64)-1)
633 root_level = btrfs_header_level(root->node);
635 root_level = btrfs_old_root_level(root, time_seq);
637 if (root_level + 1 == level) {
638 srcu_read_unlock(&fs_info->subvol_srcu, index);
642 path->lowest_level = level;
643 if (time_seq == (u64)-1)
644 ret = btrfs_search_slot(NULL, root, &ref->key_for_search, path,
647 ret = btrfs_search_old_slot(root, &ref->key_for_search, path,
650 /* root node has been locked, we can release @subvol_srcu safely here */
651 srcu_read_unlock(&fs_info->subvol_srcu, index);
654 "search slot in root %llu (level %d, ref count %d) returned %d for key (%llu %u %llu)",
655 ref->root_id, level, ref->count, ret,
656 ref->key_for_search.objectid, ref->key_for_search.type,
657 ref->key_for_search.offset);
661 eb = path->nodes[level];
663 if (WARN_ON(!level)) {
668 eb = path->nodes[level];
671 ret = add_all_parents(root, path, parents, ref, level, time_seq,
672 extent_item_pos, total_refs);
674 path->lowest_level = 0;
675 btrfs_release_path(path);
680 * resolve all indirect backrefs from the list
682 static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,
683 struct btrfs_path *path, u64 time_seq,
684 struct list_head *head,
685 const u64 *extent_item_pos, u64 total_refs,
690 struct __prelim_ref *ref;
691 struct __prelim_ref *ref_safe;
692 struct __prelim_ref *new_ref;
693 struct ulist *parents;
694 struct ulist_node *node;
695 struct ulist_iterator uiter;
697 parents = ulist_alloc(GFP_NOFS);
702 * _safe allows us to insert directly after the current item without
703 * iterating over the newly inserted items.
704 * we're also allowed to re-assign ref during iteration.
706 list_for_each_entry_safe(ref, ref_safe, head, list) {
707 if (ref->parent) /* already direct */
711 if (root_objectid && ref->root_id != root_objectid) {
712 ret = BACKREF_FOUND_SHARED;
715 err = __resolve_indirect_ref(fs_info, path, time_seq, ref,
716 parents, extent_item_pos,
719 * we can only tolerate ENOENT,otherwise,we should catch error
720 * and return directly.
722 if (err == -ENOENT) {
729 /* we put the first parent into the ref at hand */
730 ULIST_ITER_INIT(&uiter);
731 node = ulist_next(parents, &uiter);
732 ref->parent = node ? node->val : 0;
733 ref->inode_list = node ?
734 (struct extent_inode_elem *)(uintptr_t)node->aux : NULL;
736 /* additional parents require new refs being added here */
737 while ((node = ulist_next(parents, &uiter))) {
738 new_ref = kmem_cache_alloc(btrfs_prelim_ref_cache,
744 memcpy(new_ref, ref, sizeof(*ref));
745 new_ref->parent = node->val;
746 new_ref->inode_list = (struct extent_inode_elem *)
747 (uintptr_t)node->aux;
748 list_add(&new_ref->list, &ref->list);
750 ulist_reinit(parents);
757 static inline int ref_for_same_block(struct __prelim_ref *ref1,
758 struct __prelim_ref *ref2)
760 if (ref1->level != ref2->level)
762 if (ref1->root_id != ref2->root_id)
764 if (ref1->key_for_search.type != ref2->key_for_search.type)
766 if (ref1->key_for_search.objectid != ref2->key_for_search.objectid)
768 if (ref1->key_for_search.offset != ref2->key_for_search.offset)
770 if (ref1->parent != ref2->parent)
777 * read tree blocks and add keys where required.
779 static int __add_missing_keys(struct btrfs_fs_info *fs_info,
780 struct list_head *head)
782 struct __prelim_ref *ref;
783 struct extent_buffer *eb;
785 list_for_each_entry(ref, head, list) {
788 if (ref->key_for_search.type)
790 BUG_ON(!ref->wanted_disk_byte);
791 eb = read_tree_block(fs_info, ref->wanted_disk_byte, 0);
794 } else if (!extent_buffer_uptodate(eb)) {
795 free_extent_buffer(eb);
798 btrfs_tree_read_lock(eb);
799 if (btrfs_header_level(eb) == 0)
800 btrfs_item_key_to_cpu(eb, &ref->key_for_search, 0);
802 btrfs_node_key_to_cpu(eb, &ref->key_for_search, 0);
803 btrfs_tree_read_unlock(eb);
804 free_extent_buffer(eb);
810 * merge backrefs and adjust counts accordingly
812 * mode = 1: merge identical keys, if key is set
813 * FIXME: if we add more keys in __add_prelim_ref, we can merge more here.
814 * additionally, we could even add a key range for the blocks we
815 * looked into to merge even more (-> replace unresolved refs by those
817 * mode = 2: merge identical parents
819 static void __merge_refs(struct list_head *head, int mode)
821 struct __prelim_ref *pos1;
823 list_for_each_entry(pos1, head, list) {
824 struct __prelim_ref *pos2 = pos1, *tmp;
826 list_for_each_entry_safe_continue(pos2, tmp, head, list) {
827 struct __prelim_ref *ref1 = pos1, *ref2 = pos2;
828 struct extent_inode_elem *eie;
830 if (!ref_for_same_block(ref1, ref2))
833 if (!ref1->parent && ref2->parent)
836 if (ref1->parent != ref2->parent)
840 eie = ref1->inode_list;
841 while (eie && eie->next)
844 eie->next = ref2->inode_list;
846 ref1->inode_list = ref2->inode_list;
847 ref1->count += ref2->count;
849 list_del(&ref2->list);
850 kmem_cache_free(btrfs_prelim_ref_cache, ref2);
858 * add all currently queued delayed refs from this head whose seq nr is
859 * smaller or equal that seq to the list
861 static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
862 struct list_head *prefs, u64 *total_refs,
865 struct btrfs_delayed_ref_node *node;
866 struct btrfs_delayed_extent_op *extent_op = head->extent_op;
867 struct btrfs_key key;
868 struct btrfs_key op_key = {0};
872 if (extent_op && extent_op->update_key)
873 btrfs_disk_key_to_cpu(&op_key, &extent_op->key);
875 spin_lock(&head->lock);
876 list_for_each_entry(node, &head->ref_list, list) {
880 switch (node->action) {
881 case BTRFS_ADD_DELAYED_EXTENT:
882 case BTRFS_UPDATE_DELAYED_HEAD:
885 case BTRFS_ADD_DELAYED_REF:
888 case BTRFS_DROP_DELAYED_REF:
894 *total_refs += (node->ref_mod * sgn);
895 switch (node->type) {
896 case BTRFS_TREE_BLOCK_REF_KEY: {
897 struct btrfs_delayed_tree_ref *ref;
899 ref = btrfs_delayed_node_to_tree_ref(node);
900 ret = __add_prelim_ref(prefs, ref->root, &op_key,
901 ref->level + 1, 0, node->bytenr,
902 node->ref_mod * sgn, GFP_ATOMIC);
905 case BTRFS_SHARED_BLOCK_REF_KEY: {
906 struct btrfs_delayed_tree_ref *ref;
908 ref = btrfs_delayed_node_to_tree_ref(node);
909 ret = __add_prelim_ref(prefs, 0, NULL,
910 ref->level + 1, ref->parent,
912 node->ref_mod * sgn, GFP_ATOMIC);
915 case BTRFS_EXTENT_DATA_REF_KEY: {
916 struct btrfs_delayed_data_ref *ref;
917 ref = btrfs_delayed_node_to_data_ref(node);
919 key.objectid = ref->objectid;
920 key.type = BTRFS_EXTENT_DATA_KEY;
921 key.offset = ref->offset;
924 * Found a inum that doesn't match our known inum, we
927 if (inum && ref->objectid != inum) {
928 ret = BACKREF_FOUND_SHARED;
932 ret = __add_prelim_ref(prefs, ref->root, &key, 0, 0,
934 node->ref_mod * sgn, GFP_ATOMIC);
937 case BTRFS_SHARED_DATA_REF_KEY: {
938 struct btrfs_delayed_data_ref *ref;
940 ref = btrfs_delayed_node_to_data_ref(node);
941 ret = __add_prelim_ref(prefs, 0, NULL, 0,
942 ref->parent, node->bytenr,
943 node->ref_mod * sgn, GFP_ATOMIC);
952 spin_unlock(&head->lock);
957 * add all inline backrefs for bytenr to the list
959 static int __add_inline_refs(struct btrfs_path *path, u64 bytenr,
960 int *info_level, struct list_head *prefs,
961 struct ref_root *ref_tree,
962 u64 *total_refs, u64 inum)
966 struct extent_buffer *leaf;
967 struct btrfs_key key;
968 struct btrfs_key found_key;
971 struct btrfs_extent_item *ei;
976 * enumerate all inline refs
978 leaf = path->nodes[0];
979 slot = path->slots[0];
981 item_size = btrfs_item_size_nr(leaf, slot);
982 BUG_ON(item_size < sizeof(*ei));
984 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
985 flags = btrfs_extent_flags(leaf, ei);
986 *total_refs += btrfs_extent_refs(leaf, ei);
987 btrfs_item_key_to_cpu(leaf, &found_key, slot);
989 ptr = (unsigned long)(ei + 1);
990 end = (unsigned long)ei + item_size;
992 if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
993 flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
994 struct btrfs_tree_block_info *info;
996 info = (struct btrfs_tree_block_info *)ptr;
997 *info_level = btrfs_tree_block_level(leaf, info);
998 ptr += sizeof(struct btrfs_tree_block_info);
1000 } else if (found_key.type == BTRFS_METADATA_ITEM_KEY) {
1001 *info_level = found_key.offset;
1003 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
1007 struct btrfs_extent_inline_ref *iref;
1011 iref = (struct btrfs_extent_inline_ref *)ptr;
1012 type = btrfs_extent_inline_ref_type(leaf, iref);
1013 offset = btrfs_extent_inline_ref_offset(leaf, iref);
1016 case BTRFS_SHARED_BLOCK_REF_KEY:
1017 ret = __add_prelim_ref(prefs, 0, NULL,
1018 *info_level + 1, offset,
1019 bytenr, 1, GFP_NOFS);
1021 case BTRFS_SHARED_DATA_REF_KEY: {
1022 struct btrfs_shared_data_ref *sdref;
1025 sdref = (struct btrfs_shared_data_ref *)(iref + 1);
1026 count = btrfs_shared_data_ref_count(leaf, sdref);
1027 ret = __add_prelim_ref(prefs, 0, NULL, 0, offset,
1028 bytenr, count, GFP_NOFS);
1031 ret = ref_tree_add(ref_tree, 0, 0, 0,
1033 if (!ret && ref_tree->unique_refs > 1)
1034 ret = BACKREF_FOUND_SHARED;
1038 case BTRFS_TREE_BLOCK_REF_KEY:
1039 ret = __add_prelim_ref(prefs, offset, NULL,
1041 bytenr, 1, GFP_NOFS);
1043 case BTRFS_EXTENT_DATA_REF_KEY: {
1044 struct btrfs_extent_data_ref *dref;
1048 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1049 count = btrfs_extent_data_ref_count(leaf, dref);
1050 key.objectid = btrfs_extent_data_ref_objectid(leaf,
1052 key.type = BTRFS_EXTENT_DATA_KEY;
1053 key.offset = btrfs_extent_data_ref_offset(leaf, dref);
1055 if (inum && key.objectid != inum) {
1056 ret = BACKREF_FOUND_SHARED;
1060 root = btrfs_extent_data_ref_root(leaf, dref);
1061 ret = __add_prelim_ref(prefs, root, &key, 0, 0,
1062 bytenr, count, GFP_NOFS);
1065 ret = ref_tree_add(ref_tree, root,
1069 if (!ret && ref_tree->unique_refs > 1)
1070 ret = BACKREF_FOUND_SHARED;
1079 ptr += btrfs_extent_inline_ref_size(type);
1086 * add all non-inline backrefs for bytenr to the list
1088 static int __add_keyed_refs(struct btrfs_fs_info *fs_info,
1089 struct btrfs_path *path, u64 bytenr,
1090 int info_level, struct list_head *prefs,
1091 struct ref_root *ref_tree, u64 inum)
1093 struct btrfs_root *extent_root = fs_info->extent_root;
1096 struct extent_buffer *leaf;
1097 struct btrfs_key key;
1100 ret = btrfs_next_item(extent_root, path);
1108 slot = path->slots[0];
1109 leaf = path->nodes[0];
1110 btrfs_item_key_to_cpu(leaf, &key, slot);
1112 if (key.objectid != bytenr)
1114 if (key.type < BTRFS_TREE_BLOCK_REF_KEY)
1116 if (key.type > BTRFS_SHARED_DATA_REF_KEY)
1120 case BTRFS_SHARED_BLOCK_REF_KEY:
1121 ret = __add_prelim_ref(prefs, 0, NULL,
1122 info_level + 1, key.offset,
1123 bytenr, 1, GFP_NOFS);
1125 case BTRFS_SHARED_DATA_REF_KEY: {
1126 struct btrfs_shared_data_ref *sdref;
1129 sdref = btrfs_item_ptr(leaf, slot,
1130 struct btrfs_shared_data_ref);
1131 count = btrfs_shared_data_ref_count(leaf, sdref);
1132 ret = __add_prelim_ref(prefs, 0, NULL, 0, key.offset,
1133 bytenr, count, GFP_NOFS);
1136 ret = ref_tree_add(ref_tree, 0, 0, 0,
1138 if (!ret && ref_tree->unique_refs > 1)
1139 ret = BACKREF_FOUND_SHARED;
1143 case BTRFS_TREE_BLOCK_REF_KEY:
1144 ret = __add_prelim_ref(prefs, key.offset, NULL,
1146 bytenr, 1, GFP_NOFS);
1148 case BTRFS_EXTENT_DATA_REF_KEY: {
1149 struct btrfs_extent_data_ref *dref;
1153 dref = btrfs_item_ptr(leaf, slot,
1154 struct btrfs_extent_data_ref);
1155 count = btrfs_extent_data_ref_count(leaf, dref);
1156 key.objectid = btrfs_extent_data_ref_objectid(leaf,
1158 key.type = BTRFS_EXTENT_DATA_KEY;
1159 key.offset = btrfs_extent_data_ref_offset(leaf, dref);
1161 if (inum && key.objectid != inum) {
1162 ret = BACKREF_FOUND_SHARED;
1166 root = btrfs_extent_data_ref_root(leaf, dref);
1167 ret = __add_prelim_ref(prefs, root, &key, 0, 0,
1168 bytenr, count, GFP_NOFS);
1171 ret = ref_tree_add(ref_tree, root,
1175 if (!ret && ref_tree->unique_refs > 1)
1176 ret = BACKREF_FOUND_SHARED;
1192 * this adds all existing backrefs (inline backrefs, backrefs and delayed
1193 * refs) for the given bytenr to the refs list, merges duplicates and resolves
1194 * indirect refs to their parent bytenr.
1195 * When roots are found, they're added to the roots list
1197 * NOTE: This can return values > 0
1199 * If time_seq is set to (u64)-1, it will not search delayed_refs, and behave
1200 * much like trans == NULL case, the difference only lies in it will not
1202 * The special case is for qgroup to search roots in commit_transaction().
1204 * If check_shared is set to 1, any extent has more than one ref item, will
1205 * be returned BACKREF_FOUND_SHARED immediately.
1207 * FIXME some caching might speed things up
1209 static int find_parent_nodes(struct btrfs_trans_handle *trans,
1210 struct btrfs_fs_info *fs_info, u64 bytenr,
1211 u64 time_seq, struct ulist *refs,
1212 struct ulist *roots, const u64 *extent_item_pos,
1213 u64 root_objectid, u64 inum, int check_shared)
1215 struct btrfs_key key;
1216 struct btrfs_path *path;
1217 struct btrfs_delayed_ref_root *delayed_refs = NULL;
1218 struct btrfs_delayed_ref_head *head;
1221 struct list_head prefs_delayed;
1222 struct list_head prefs;
1223 struct __prelim_ref *ref;
1224 struct extent_inode_elem *eie = NULL;
1225 struct ref_root *ref_tree = NULL;
1228 INIT_LIST_HEAD(&prefs);
1229 INIT_LIST_HEAD(&prefs_delayed);
1231 key.objectid = bytenr;
1232 key.offset = (u64)-1;
1233 if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
1234 key.type = BTRFS_METADATA_ITEM_KEY;
1236 key.type = BTRFS_EXTENT_ITEM_KEY;
1238 path = btrfs_alloc_path();
1242 path->search_commit_root = 1;
1243 path->skip_locking = 1;
1246 if (time_seq == (u64)-1)
1247 path->skip_locking = 1;
1250 * grab both a lock on the path and a lock on the delayed ref head.
1251 * We need both to get a consistent picture of how the refs look
1252 * at a specified point in time
1259 ref_tree = ref_root_alloc();
1265 ref_root_fini(ref_tree);
1269 ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
1274 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
1275 if (trans && likely(trans->type != __TRANS_DUMMY) &&
1276 time_seq != (u64)-1) {
1278 if (trans && time_seq != (u64)-1) {
1281 * look if there are updates for this ref queued and lock the
1284 delayed_refs = &trans->transaction->delayed_refs;
1285 spin_lock(&delayed_refs->lock);
1286 head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
1288 if (!mutex_trylock(&head->mutex)) {
1289 refcount_inc(&head->node.refs);
1290 spin_unlock(&delayed_refs->lock);
1292 btrfs_release_path(path);
1295 * Mutex was contended, block until it's
1296 * released and try again
1298 mutex_lock(&head->mutex);
1299 mutex_unlock(&head->mutex);
1300 btrfs_put_delayed_ref(&head->node);
1303 spin_unlock(&delayed_refs->lock);
1304 ret = __add_delayed_refs(head, time_seq,
1305 &prefs_delayed, &total_refs,
1307 mutex_unlock(&head->mutex);
1311 spin_unlock(&delayed_refs->lock);
1314 if (check_shared && !list_empty(&prefs_delayed)) {
1316 * Add all delay_ref to the ref_tree and check if there
1317 * are multiple ref items added.
1319 list_for_each_entry(ref, &prefs_delayed, list) {
1320 if (ref->key_for_search.type) {
1321 ret = ref_tree_add(ref_tree,
1323 ref->key_for_search.objectid,
1324 ref->key_for_search.offset,
1329 ret = ref_tree_add(ref_tree, 0, 0, 0,
1330 ref->parent, ref->count);
1337 if (ref_tree->unique_refs > 1) {
1338 ret = BACKREF_FOUND_SHARED;
1345 if (path->slots[0]) {
1346 struct extent_buffer *leaf;
1350 leaf = path->nodes[0];
1351 slot = path->slots[0];
1352 btrfs_item_key_to_cpu(leaf, &key, slot);
1353 if (key.objectid == bytenr &&
1354 (key.type == BTRFS_EXTENT_ITEM_KEY ||
1355 key.type == BTRFS_METADATA_ITEM_KEY)) {
1356 ret = __add_inline_refs(path, bytenr,
1357 &info_level, &prefs,
1358 ref_tree, &total_refs,
1362 ret = __add_keyed_refs(fs_info, path, bytenr,
1369 btrfs_release_path(path);
1371 list_splice_init(&prefs_delayed, &prefs);
1373 ret = __add_missing_keys(fs_info, &prefs);
1377 __merge_refs(&prefs, 1);
1379 ret = __resolve_indirect_refs(fs_info, path, time_seq, &prefs,
1380 extent_item_pos, total_refs,
1385 __merge_refs(&prefs, 2);
1387 while (!list_empty(&prefs)) {
1388 ref = list_first_entry(&prefs, struct __prelim_ref, list);
1389 WARN_ON(ref->count < 0);
1390 if (roots && ref->count && ref->root_id && ref->parent == 0) {
1391 if (root_objectid && ref->root_id != root_objectid) {
1392 ret = BACKREF_FOUND_SHARED;
1396 /* no parent == root of tree */
1397 ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS);
1401 if (ref->count && ref->parent) {
1402 if (extent_item_pos && !ref->inode_list &&
1404 struct extent_buffer *eb;
1406 eb = read_tree_block(fs_info, ref->parent, 0);
1410 } else if (!extent_buffer_uptodate(eb)) {
1411 free_extent_buffer(eb);
1415 btrfs_tree_read_lock(eb);
1416 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
1417 ret = find_extent_in_eb(eb, bytenr,
1418 *extent_item_pos, &eie);
1419 btrfs_tree_read_unlock_blocking(eb);
1420 free_extent_buffer(eb);
1423 ref->inode_list = eie;
1425 ret = ulist_add_merge_ptr(refs, ref->parent,
1427 (void **)&eie, GFP_NOFS);
1430 if (!ret && extent_item_pos) {
1432 * we've recorded that parent, so we must extend
1433 * its inode list here
1438 eie->next = ref->inode_list;
1442 list_del(&ref->list);
1443 kmem_cache_free(btrfs_prelim_ref_cache, ref);
1447 btrfs_free_path(path);
1448 ref_root_free(ref_tree);
1449 while (!list_empty(&prefs)) {
1450 ref = list_first_entry(&prefs, struct __prelim_ref, list);
1451 list_del(&ref->list);
1452 kmem_cache_free(btrfs_prelim_ref_cache, ref);
1454 while (!list_empty(&prefs_delayed)) {
1455 ref = list_first_entry(&prefs_delayed, struct __prelim_ref,
1457 list_del(&ref->list);
1458 kmem_cache_free(btrfs_prelim_ref_cache, ref);
1461 free_inode_elem_list(eie);
1465 static void free_leaf_list(struct ulist *blocks)
1467 struct ulist_node *node = NULL;
1468 struct extent_inode_elem *eie;
1469 struct ulist_iterator uiter;
1471 ULIST_ITER_INIT(&uiter);
1472 while ((node = ulist_next(blocks, &uiter))) {
1475 eie = (struct extent_inode_elem *)(uintptr_t)node->aux;
1476 free_inode_elem_list(eie);
1484 * Finds all leafs with a reference to the specified combination of bytenr and
1485 * offset. key_list_head will point to a list of corresponding keys (caller must
1486 * free each list element). The leafs will be stored in the leafs ulist, which
1487 * must be freed with ulist_free.
1489 * returns 0 on success, <0 on error
1491 static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
1492 struct btrfs_fs_info *fs_info, u64 bytenr,
1493 u64 time_seq, struct ulist **leafs,
1494 const u64 *extent_item_pos)
1498 *leafs = ulist_alloc(GFP_NOFS);
1502 ret = find_parent_nodes(trans, fs_info, bytenr, time_seq,
1503 *leafs, NULL, extent_item_pos, 0, 0, 0);
1504 if (ret < 0 && ret != -ENOENT) {
1505 free_leaf_list(*leafs);
1513 * walk all backrefs for a given extent to find all roots that reference this
1514 * extent. Walking a backref means finding all extents that reference this
1515 * extent and in turn walk the backrefs of those, too. Naturally this is a
1516 * recursive process, but here it is implemented in an iterative fashion: We
1517 * find all referencing extents for the extent in question and put them on a
1518 * list. In turn, we find all referencing extents for those, further appending
1519 * to the list. The way we iterate the list allows adding more elements after
1520 * the current while iterating. The process stops when we reach the end of the
1521 * list. Found roots are added to the roots list.
1523 * returns 0 on success, < 0 on error.
1525 static int __btrfs_find_all_roots(struct btrfs_trans_handle *trans,
1526 struct btrfs_fs_info *fs_info, u64 bytenr,
1527 u64 time_seq, struct ulist **roots)
1530 struct ulist_node *node = NULL;
1531 struct ulist_iterator uiter;
1534 tmp = ulist_alloc(GFP_NOFS);
1537 *roots = ulist_alloc(GFP_NOFS);
1543 ULIST_ITER_INIT(&uiter);
1545 ret = find_parent_nodes(trans, fs_info, bytenr, time_seq,
1546 tmp, *roots, NULL, 0, 0, 0);
1547 if (ret < 0 && ret != -ENOENT) {
1552 node = ulist_next(tmp, &uiter);
1563 int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
1564 struct btrfs_fs_info *fs_info, u64 bytenr,
1565 u64 time_seq, struct ulist **roots)
1570 down_read(&fs_info->commit_root_sem);
1571 ret = __btrfs_find_all_roots(trans, fs_info, bytenr, time_seq, roots);
1573 up_read(&fs_info->commit_root_sem);
1578 * btrfs_check_shared - tell us whether an extent is shared
1580 * @trans: optional trans handle
1582 * btrfs_check_shared uses the backref walking code but will short
1583 * circuit as soon as it finds a root or inode that doesn't match the
1584 * one passed in. This provides a significant performance benefit for
1585 * callers (such as fiemap) which want to know whether the extent is
1586 * shared but do not need a ref count.
1588 * Return: 0 if extent is not shared, 1 if it is shared, < 0 on error.
1590 int btrfs_check_shared(struct btrfs_trans_handle *trans,
1591 struct btrfs_fs_info *fs_info, u64 root_objectid,
1592 u64 inum, u64 bytenr)
1594 struct ulist *tmp = NULL;
1595 struct ulist *roots = NULL;
1596 struct ulist_iterator uiter;
1597 struct ulist_node *node;
1598 struct seq_list elem = SEQ_LIST_INIT(elem);
1601 tmp = ulist_alloc(GFP_NOFS);
1602 roots = ulist_alloc(GFP_NOFS);
1603 if (!tmp || !roots) {
1610 btrfs_get_tree_mod_seq(fs_info, &elem);
1612 down_read(&fs_info->commit_root_sem);
1613 ULIST_ITER_INIT(&uiter);
1615 ret = find_parent_nodes(trans, fs_info, bytenr, elem.seq, tmp,
1616 roots, NULL, root_objectid, inum, 1);
1617 if (ret == BACKREF_FOUND_SHARED) {
1618 /* this is the only condition under which we return 1 */
1622 if (ret < 0 && ret != -ENOENT)
1625 node = ulist_next(tmp, &uiter);
1632 btrfs_put_tree_mod_seq(fs_info, &elem);
1634 up_read(&fs_info->commit_root_sem);
1640 int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
1641 u64 start_off, struct btrfs_path *path,
1642 struct btrfs_inode_extref **ret_extref,
1646 struct btrfs_key key;
1647 struct btrfs_key found_key;
1648 struct btrfs_inode_extref *extref;
1649 struct extent_buffer *leaf;
1652 key.objectid = inode_objectid;
1653 key.type = BTRFS_INODE_EXTREF_KEY;
1654 key.offset = start_off;
1656 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1661 leaf = path->nodes[0];
1662 slot = path->slots[0];
1663 if (slot >= btrfs_header_nritems(leaf)) {
1665 * If the item at offset is not found,
1666 * btrfs_search_slot will point us to the slot
1667 * where it should be inserted. In our case
1668 * that will be the slot directly before the
1669 * next INODE_REF_KEY_V2 item. In the case
1670 * that we're pointing to the last slot in a
1671 * leaf, we must move one leaf over.
1673 ret = btrfs_next_leaf(root, path);
1682 btrfs_item_key_to_cpu(leaf, &found_key, slot);
1685 * Check that we're still looking at an extended ref key for
1686 * this particular objectid. If we have different
1687 * objectid or type then there are no more to be found
1688 * in the tree and we can exit.
1691 if (found_key.objectid != inode_objectid)
1693 if (found_key.type != BTRFS_INODE_EXTREF_KEY)
1697 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
1698 extref = (struct btrfs_inode_extref *)ptr;
1699 *ret_extref = extref;
1701 *found_off = found_key.offset;
1709 * this iterates to turn a name (from iref/extref) into a full filesystem path.
1710 * Elements of the path are separated by '/' and the path is guaranteed to be
1711 * 0-terminated. the path is only given within the current file system.
1712 * Therefore, it never starts with a '/'. the caller is responsible to provide
1713 * "size" bytes in "dest". the dest buffer will be filled backwards. finally,
1714 * the start point of the resulting string is returned. this pointer is within
1716 * in case the path buffer would overflow, the pointer is decremented further
1717 * as if output was written to the buffer, though no more output is actually
1718 * generated. that way, the caller can determine how much space would be
1719 * required for the path to fit into the buffer. in that case, the returned
1720 * value will be smaller than dest. callers must check this!
1722 char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
1723 u32 name_len, unsigned long name_off,
1724 struct extent_buffer *eb_in, u64 parent,
1725 char *dest, u32 size)
1730 s64 bytes_left = ((s64)size) - 1;
1731 struct extent_buffer *eb = eb_in;
1732 struct btrfs_key found_key;
1733 int leave_spinning = path->leave_spinning;
1734 struct btrfs_inode_ref *iref;
1736 if (bytes_left >= 0)
1737 dest[bytes_left] = '\0';
1739 path->leave_spinning = 1;
1741 bytes_left -= name_len;
1742 if (bytes_left >= 0)
1743 read_extent_buffer(eb, dest + bytes_left,
1744 name_off, name_len);
1746 if (!path->skip_locking)
1747 btrfs_tree_read_unlock_blocking(eb);
1748 free_extent_buffer(eb);
1750 ret = btrfs_find_item(fs_root, path, parent, 0,
1751 BTRFS_INODE_REF_KEY, &found_key);
1757 next_inum = found_key.offset;
1759 /* regular exit ahead */
1760 if (parent == next_inum)
1763 slot = path->slots[0];
1764 eb = path->nodes[0];
1765 /* make sure we can use eb after releasing the path */
1767 if (!path->skip_locking)
1768 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
1769 path->nodes[0] = NULL;
1772 btrfs_release_path(path);
1773 iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
1775 name_len = btrfs_inode_ref_name_len(eb, iref);
1776 name_off = (unsigned long)(iref + 1);
1780 if (bytes_left >= 0)
1781 dest[bytes_left] = '/';
1784 btrfs_release_path(path);
1785 path->leave_spinning = leave_spinning;
1788 return ERR_PTR(ret);
1790 return dest + bytes_left;
1794 * this makes the path point to (logical EXTENT_ITEM *)
1795 * returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for
1796 * tree blocks and <0 on error.
1798 int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
1799 struct btrfs_path *path, struct btrfs_key *found_key,
1806 struct extent_buffer *eb;
1807 struct btrfs_extent_item *ei;
1808 struct btrfs_key key;
1810 if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
1811 key.type = BTRFS_METADATA_ITEM_KEY;
1813 key.type = BTRFS_EXTENT_ITEM_KEY;
1814 key.objectid = logical;
1815 key.offset = (u64)-1;
1817 ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
1821 ret = btrfs_previous_extent_item(fs_info->extent_root, path, 0);
1827 btrfs_item_key_to_cpu(path->nodes[0], found_key, path->slots[0]);
1828 if (found_key->type == BTRFS_METADATA_ITEM_KEY)
1829 size = fs_info->nodesize;
1830 else if (found_key->type == BTRFS_EXTENT_ITEM_KEY)
1831 size = found_key->offset;
1833 if (found_key->objectid > logical ||
1834 found_key->objectid + size <= logical) {
1835 btrfs_debug(fs_info,
1836 "logical %llu is not within any extent", logical);
1840 eb = path->nodes[0];
1841 item_size = btrfs_item_size_nr(eb, path->slots[0]);
1842 BUG_ON(item_size < sizeof(*ei));
1844 ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
1845 flags = btrfs_extent_flags(eb, ei);
1847 btrfs_debug(fs_info,
1848 "logical %llu is at position %llu within the extent (%llu EXTENT_ITEM %llu) flags %#llx size %u",
1849 logical, logical - found_key->objectid, found_key->objectid,
1850 found_key->offset, flags, item_size);
1852 WARN_ON(!flags_ret);
1854 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
1855 *flags_ret = BTRFS_EXTENT_FLAG_TREE_BLOCK;
1856 else if (flags & BTRFS_EXTENT_FLAG_DATA)
1857 *flags_ret = BTRFS_EXTENT_FLAG_DATA;
1867 * helper function to iterate extent inline refs. ptr must point to a 0 value
1868 * for the first call and may be modified. it is used to track state.
1869 * if more refs exist, 0 is returned and the next call to
1870 * __get_extent_inline_ref must pass the modified ptr parameter to get the
1871 * next ref. after the last ref was processed, 1 is returned.
1872 * returns <0 on error
1874 static int __get_extent_inline_ref(unsigned long *ptr, struct extent_buffer *eb,
1875 struct btrfs_key *key,
1876 struct btrfs_extent_item *ei, u32 item_size,
1877 struct btrfs_extent_inline_ref **out_eiref,
1882 struct btrfs_tree_block_info *info;
1886 flags = btrfs_extent_flags(eb, ei);
1887 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1888 if (key->type == BTRFS_METADATA_ITEM_KEY) {
1889 /* a skinny metadata extent */
1891 (struct btrfs_extent_inline_ref *)(ei + 1);
1893 WARN_ON(key->type != BTRFS_EXTENT_ITEM_KEY);
1894 info = (struct btrfs_tree_block_info *)(ei + 1);
1896 (struct btrfs_extent_inline_ref *)(info + 1);
1899 *out_eiref = (struct btrfs_extent_inline_ref *)(ei + 1);
1901 *ptr = (unsigned long)*out_eiref;
1902 if ((unsigned long)(*ptr) >= (unsigned long)ei + item_size)
1906 end = (unsigned long)ei + item_size;
1907 *out_eiref = (struct btrfs_extent_inline_ref *)(*ptr);
1908 *out_type = btrfs_extent_inline_ref_type(eb, *out_eiref);
1910 *ptr += btrfs_extent_inline_ref_size(*out_type);
1911 WARN_ON(*ptr > end);
1913 return 1; /* last */
1919 * reads the tree block backref for an extent. tree level and root are returned
1920 * through out_level and out_root. ptr must point to a 0 value for the first
1921 * call and may be modified (see __get_extent_inline_ref comment).
1922 * returns 0 if data was provided, 1 if there was no more data to provide or
1925 int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
1926 struct btrfs_key *key, struct btrfs_extent_item *ei,
1927 u32 item_size, u64 *out_root, u8 *out_level)
1931 struct btrfs_extent_inline_ref *eiref;
1933 if (*ptr == (unsigned long)-1)
1937 ret = __get_extent_inline_ref(ptr, eb, key, ei, item_size,
1942 if (type == BTRFS_TREE_BLOCK_REF_KEY ||
1943 type == BTRFS_SHARED_BLOCK_REF_KEY)
1950 /* we can treat both ref types equally here */
1951 *out_root = btrfs_extent_inline_ref_offset(eb, eiref);
1953 if (key->type == BTRFS_EXTENT_ITEM_KEY) {
1954 struct btrfs_tree_block_info *info;
1956 info = (struct btrfs_tree_block_info *)(ei + 1);
1957 *out_level = btrfs_tree_block_level(eb, info);
1959 ASSERT(key->type == BTRFS_METADATA_ITEM_KEY);
1960 *out_level = (u8)key->offset;
1964 *ptr = (unsigned long)-1;
1969 static int iterate_leaf_refs(struct btrfs_fs_info *fs_info,
1970 struct extent_inode_elem *inode_list,
1971 u64 root, u64 extent_item_objectid,
1972 iterate_extent_inodes_t *iterate, void *ctx)
1974 struct extent_inode_elem *eie;
1977 for (eie = inode_list; eie; eie = eie->next) {
1978 btrfs_debug(fs_info,
1979 "ref for %llu resolved, key (%llu EXTEND_DATA %llu), root %llu",
1980 extent_item_objectid, eie->inum,
1982 ret = iterate(eie->inum, eie->offset, root, ctx);
1984 btrfs_debug(fs_info,
1985 "stopping iteration for %llu due to ret=%d",
1986 extent_item_objectid, ret);
1995 * calls iterate() for every inode that references the extent identified by
1996 * the given parameters.
1997 * when the iterator function returns a non-zero value, iteration stops.
1999 int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
2000 u64 extent_item_objectid, u64 extent_item_pos,
2001 int search_commit_root,
2002 iterate_extent_inodes_t *iterate, void *ctx)
2005 struct btrfs_trans_handle *trans = NULL;
2006 struct ulist *refs = NULL;
2007 struct ulist *roots = NULL;
2008 struct ulist_node *ref_node = NULL;
2009 struct ulist_node *root_node = NULL;
2010 struct seq_list tree_mod_seq_elem = SEQ_LIST_INIT(tree_mod_seq_elem);
2011 struct ulist_iterator ref_uiter;
2012 struct ulist_iterator root_uiter;
2014 btrfs_debug(fs_info, "resolving all inodes for extent %llu",
2015 extent_item_objectid);
2017 if (!search_commit_root) {
2018 trans = btrfs_join_transaction(fs_info->extent_root);
2020 return PTR_ERR(trans);
2021 btrfs_get_tree_mod_seq(fs_info, &tree_mod_seq_elem);
2023 down_read(&fs_info->commit_root_sem);
2026 ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid,
2027 tree_mod_seq_elem.seq, &refs,
2032 ULIST_ITER_INIT(&ref_uiter);
2033 while (!ret && (ref_node = ulist_next(refs, &ref_uiter))) {
2034 ret = __btrfs_find_all_roots(trans, fs_info, ref_node->val,
2035 tree_mod_seq_elem.seq, &roots);
2038 ULIST_ITER_INIT(&root_uiter);
2039 while (!ret && (root_node = ulist_next(roots, &root_uiter))) {
2040 btrfs_debug(fs_info,
2041 "root %llu references leaf %llu, data list %#llx",
2042 root_node->val, ref_node->val,
2044 ret = iterate_leaf_refs(fs_info,
2045 (struct extent_inode_elem *)
2046 (uintptr_t)ref_node->aux,
2048 extent_item_objectid,
2054 free_leaf_list(refs);
2056 if (!search_commit_root) {
2057 btrfs_put_tree_mod_seq(fs_info, &tree_mod_seq_elem);
2058 btrfs_end_transaction(trans);
2060 up_read(&fs_info->commit_root_sem);
2066 int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
2067 struct btrfs_path *path,
2068 iterate_extent_inodes_t *iterate, void *ctx)
2071 u64 extent_item_pos;
2073 struct btrfs_key found_key;
2074 int search_commit_root = path->search_commit_root;
2076 ret = extent_from_logical(fs_info, logical, path, &found_key, &flags);
2077 btrfs_release_path(path);
2080 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
2083 extent_item_pos = logical - found_key.objectid;
2084 ret = iterate_extent_inodes(fs_info, found_key.objectid,
2085 extent_item_pos, search_commit_root,
2091 typedef int (iterate_irefs_t)(u64 parent, u32 name_len, unsigned long name_off,
2092 struct extent_buffer *eb, void *ctx);
2094 static int iterate_inode_refs(u64 inum, struct btrfs_root *fs_root,
2095 struct btrfs_path *path,
2096 iterate_irefs_t *iterate, void *ctx)
2105 struct extent_buffer *eb;
2106 struct btrfs_item *item;
2107 struct btrfs_inode_ref *iref;
2108 struct btrfs_key found_key;
2111 ret = btrfs_find_item(fs_root, path, inum,
2112 parent ? parent + 1 : 0, BTRFS_INODE_REF_KEY,
2118 ret = found ? 0 : -ENOENT;
2123 parent = found_key.offset;
2124 slot = path->slots[0];
2125 eb = btrfs_clone_extent_buffer(path->nodes[0]);
2130 extent_buffer_get(eb);
2131 btrfs_tree_read_lock(eb);
2132 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
2133 btrfs_release_path(path);
2135 item = btrfs_item_nr(slot);
2136 iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
2138 for (cur = 0; cur < btrfs_item_size(eb, item); cur += len) {
2139 name_len = btrfs_inode_ref_name_len(eb, iref);
2140 /* path must be released before calling iterate()! */
2141 btrfs_debug(fs_root->fs_info,
2142 "following ref at offset %u for inode %llu in tree %llu",
2143 cur, found_key.objectid, fs_root->objectid);
2144 ret = iterate(parent, name_len,
2145 (unsigned long)(iref + 1), eb, ctx);
2148 len = sizeof(*iref) + name_len;
2149 iref = (struct btrfs_inode_ref *)((char *)iref + len);
2151 btrfs_tree_read_unlock_blocking(eb);
2152 free_extent_buffer(eb);
2155 btrfs_release_path(path);
2160 static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root,
2161 struct btrfs_path *path,
2162 iterate_irefs_t *iterate, void *ctx)
2169 struct extent_buffer *eb;
2170 struct btrfs_inode_extref *extref;
2176 ret = btrfs_find_one_extref(fs_root, inum, offset, path, &extref,
2181 ret = found ? 0 : -ENOENT;
2186 slot = path->slots[0];
2187 eb = btrfs_clone_extent_buffer(path->nodes[0]);
2192 extent_buffer_get(eb);
2194 btrfs_tree_read_lock(eb);
2195 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
2196 btrfs_release_path(path);
2198 item_size = btrfs_item_size_nr(eb, slot);
2199 ptr = btrfs_item_ptr_offset(eb, slot);
2202 while (cur_offset < item_size) {
2205 extref = (struct btrfs_inode_extref *)(ptr + cur_offset);
2206 parent = btrfs_inode_extref_parent(eb, extref);
2207 name_len = btrfs_inode_extref_name_len(eb, extref);
2208 ret = iterate(parent, name_len,
2209 (unsigned long)&extref->name, eb, ctx);
2213 cur_offset += btrfs_inode_extref_name_len(eb, extref);
2214 cur_offset += sizeof(*extref);
2216 btrfs_tree_read_unlock_blocking(eb);
2217 free_extent_buffer(eb);
2222 btrfs_release_path(path);
2227 static int iterate_irefs(u64 inum, struct btrfs_root *fs_root,
2228 struct btrfs_path *path, iterate_irefs_t *iterate,
2234 ret = iterate_inode_refs(inum, fs_root, path, iterate, ctx);
2237 else if (ret != -ENOENT)
2240 ret = iterate_inode_extrefs(inum, fs_root, path, iterate, ctx);
2241 if (ret == -ENOENT && found_refs)
2248 * returns 0 if the path could be dumped (probably truncated)
2249 * returns <0 in case of an error
2251 static int inode_to_path(u64 inum, u32 name_len, unsigned long name_off,
2252 struct extent_buffer *eb, void *ctx)
2254 struct inode_fs_paths *ipath = ctx;
2257 int i = ipath->fspath->elem_cnt;
2258 const int s_ptr = sizeof(char *);
2261 bytes_left = ipath->fspath->bytes_left > s_ptr ?
2262 ipath->fspath->bytes_left - s_ptr : 0;
2264 fspath_min = (char *)ipath->fspath->val + (i + 1) * s_ptr;
2265 fspath = btrfs_ref_to_path(ipath->fs_root, ipath->btrfs_path, name_len,
2266 name_off, eb, inum, fspath_min, bytes_left);
2268 return PTR_ERR(fspath);
2270 if (fspath > fspath_min) {
2271 ipath->fspath->val[i] = (u64)(unsigned long)fspath;
2272 ++ipath->fspath->elem_cnt;
2273 ipath->fspath->bytes_left = fspath - fspath_min;
2275 ++ipath->fspath->elem_missed;
2276 ipath->fspath->bytes_missing += fspath_min - fspath;
2277 ipath->fspath->bytes_left = 0;
2284 * this dumps all file system paths to the inode into the ipath struct, provided
2285 * is has been created large enough. each path is zero-terminated and accessed
2286 * from ipath->fspath->val[i].
2287 * when it returns, there are ipath->fspath->elem_cnt number of paths available
2288 * in ipath->fspath->val[]. when the allocated space wasn't sufficient, the
2289 * number of missed paths is recorded in ipath->fspath->elem_missed, otherwise,
2290 * it's zero. ipath->fspath->bytes_missing holds the number of bytes that would
2291 * have been needed to return all paths.
2293 int paths_from_inode(u64 inum, struct inode_fs_paths *ipath)
2295 return iterate_irefs(inum, ipath->fs_root, ipath->btrfs_path,
2296 inode_to_path, ipath);
2299 struct btrfs_data_container *init_data_container(u32 total_bytes)
2301 struct btrfs_data_container *data;
2304 alloc_bytes = max_t(size_t, total_bytes, sizeof(*data));
2305 data = vmalloc(alloc_bytes);
2307 return ERR_PTR(-ENOMEM);
2309 if (total_bytes >= sizeof(*data)) {
2310 data->bytes_left = total_bytes - sizeof(*data);
2311 data->bytes_missing = 0;
2313 data->bytes_missing = sizeof(*data) - total_bytes;
2314 data->bytes_left = 0;
2318 data->elem_missed = 0;
2324 * allocates space to return multiple file system paths for an inode.
2325 * total_bytes to allocate are passed, note that space usable for actual path
2326 * information will be total_bytes - sizeof(struct inode_fs_paths).
2327 * the returned pointer must be freed with free_ipath() in the end.
2329 struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root,
2330 struct btrfs_path *path)
2332 struct inode_fs_paths *ifp;
2333 struct btrfs_data_container *fspath;
2335 fspath = init_data_container(total_bytes);
2337 return (void *)fspath;
2339 ifp = kmalloc(sizeof(*ifp), GFP_NOFS);
2342 return ERR_PTR(-ENOMEM);
2345 ifp->btrfs_path = path;
2346 ifp->fspath = fspath;
2347 ifp->fs_root = fs_root;
2352 void free_ipath(struct inode_fs_paths *ipath)
2356 vfree(ipath->fspath);