2 * Copyright (C) 2011 STRATO. All rights reserved.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
19 #include <linux/vmalloc.h>
24 #include "transaction.h"
25 #include "delayed-ref.h"
28 struct extent_inode_elem
{
31 struct extent_inode_elem
*next
;
34 static int check_extent_in_eb(struct btrfs_key
*key
, struct extent_buffer
*eb
,
35 struct btrfs_file_extent_item
*fi
,
37 struct extent_inode_elem
**eie
)
41 struct extent_inode_elem
*e
;
43 data_offset
= btrfs_file_extent_offset(eb
, fi
);
44 data_len
= btrfs_file_extent_num_bytes(eb
, fi
);
46 if (extent_item_pos
< data_offset
||
47 extent_item_pos
>= data_offset
+ data_len
)
50 e
= kmalloc(sizeof(*e
), GFP_NOFS
);
55 e
->inum
= key
->objectid
;
56 e
->offset
= key
->offset
+ (extent_item_pos
- data_offset
);
62 static int find_extent_in_eb(struct extent_buffer
*eb
, u64 wanted_disk_byte
,
64 struct extent_inode_elem
**eie
)
68 struct btrfs_file_extent_item
*fi
;
75 * from the shared data ref, we only have the leaf but we need
76 * the key. thus, we must look into all items and see that we
77 * find one (some) with a reference to our extent item.
79 nritems
= btrfs_header_nritems(eb
);
80 for (slot
= 0; slot
< nritems
; ++slot
) {
81 btrfs_item_key_to_cpu(eb
, &key
, slot
);
82 if (key
.type
!= BTRFS_EXTENT_DATA_KEY
)
84 fi
= btrfs_item_ptr(eb
, slot
, struct btrfs_file_extent_item
);
85 extent_type
= btrfs_file_extent_type(eb
, fi
);
86 if (extent_type
== BTRFS_FILE_EXTENT_INLINE
)
88 /* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */
89 disk_byte
= btrfs_file_extent_disk_bytenr(eb
, fi
);
90 if (disk_byte
!= wanted_disk_byte
)
93 ret
= check_extent_in_eb(&key
, eb
, fi
, extent_item_pos
, eie
);
102 * this structure records all encountered refs on the way up to the root
104 struct __prelim_ref
{
105 struct list_head list
;
107 struct btrfs_key key_for_search
;
110 struct extent_inode_elem
*inode_list
;
112 u64 wanted_disk_byte
;
116 * the rules for all callers of this function are:
117 * - obtaining the parent is the goal
118 * - if you add a key, you must know that it is a correct key
119 * - if you cannot add the parent or a correct key, then we will look into the
120 * block later to set a correct key
124 * backref type | shared | indirect | shared | indirect
125 * information | tree | tree | data | data
126 * --------------------+--------+----------+--------+----------
127 * parent logical | y | - | - | -
128 * key to resolve | - | y | y | y
129 * tree block logical | - | - | - | -
130 * root for resolving | y | y | y | y
132 * - column 1: we've the parent -> done
133 * - column 2, 3, 4: we use the key to find the parent
135 * on disk refs (inline or keyed)
136 * ==============================
137 * backref type | shared | indirect | shared | indirect
138 * information | tree | tree | data | data
139 * --------------------+--------+----------+--------+----------
140 * parent logical | y | - | y | -
141 * key to resolve | - | - | - | y
142 * tree block logical | y | y | y | y
143 * root for resolving | - | y | y | y
145 * - column 1, 3: we've the parent -> done
146 * - column 2: we take the first key from the block to find the parent
147 * (see __add_missing_keys)
148 * - column 4: we use the key to find the parent
150 * additional information that's available but not required to find the parent
151 * block might help in merging entries to gain some speed.
154 static int __add_prelim_ref(struct list_head
*head
, u64 root_id
,
155 struct btrfs_key
*key
, int level
,
156 u64 parent
, u64 wanted_disk_byte
, int count
)
158 struct __prelim_ref
*ref
;
160 /* in case we're adding delayed refs, we're holding the refs spinlock */
161 ref
= kmalloc(sizeof(*ref
), GFP_ATOMIC
);
165 ref
->root_id
= root_id
;
167 ref
->key_for_search
= *key
;
169 memset(&ref
->key_for_search
, 0, sizeof(ref
->key_for_search
));
171 ref
->inode_list
= NULL
;
174 ref
->parent
= parent
;
175 ref
->wanted_disk_byte
= wanted_disk_byte
;
176 list_add_tail(&ref
->list
, head
);
181 static int add_all_parents(struct btrfs_root
*root
, struct btrfs_path
*path
,
182 struct ulist
*parents
, int level
,
183 struct btrfs_key
*key_for_search
, u64 time_seq
,
184 u64 wanted_disk_byte
,
185 const u64
*extent_item_pos
)
189 struct extent_buffer
*eb
;
190 struct btrfs_key key
;
191 struct btrfs_file_extent_item
*fi
;
192 struct extent_inode_elem
*eie
= NULL
;
196 eb
= path
->nodes
[level
];
197 ret
= ulist_add(parents
, eb
->start
, 0, GFP_NOFS
);
204 * We normally enter this function with the path already pointing to
205 * the first item to check. But sometimes, we may enter it with
206 * slot==nritems. In that case, go to the next leaf before we continue.
208 if (path
->slots
[0] >= btrfs_header_nritems(path
->nodes
[0]))
209 ret
= btrfs_next_old_leaf(root
, path
, time_seq
);
213 slot
= path
->slots
[0];
215 btrfs_item_key_to_cpu(eb
, &key
, slot
);
217 if (key
.objectid
!= key_for_search
->objectid
||
218 key
.type
!= BTRFS_EXTENT_DATA_KEY
)
221 fi
= btrfs_item_ptr(eb
, slot
, struct btrfs_file_extent_item
);
222 disk_byte
= btrfs_file_extent_disk_bytenr(eb
, fi
);
224 if (disk_byte
== wanted_disk_byte
) {
226 if (extent_item_pos
) {
227 ret
= check_extent_in_eb(&key
, eb
, fi
,
234 ret
= ulist_add(parents
, eb
->start
,
235 (uintptr_t)eie
, GFP_NOFS
);
238 if (!extent_item_pos
) {
239 ret
= btrfs_next_old_leaf(root
, path
,
245 ret
= btrfs_next_old_item(root
, path
, time_seq
);
254 * resolve an indirect backref in the form (root_id, key, level)
255 * to a logical address
257 static int __resolve_indirect_ref(struct btrfs_fs_info
*fs_info
,
258 int search_commit_root
,
260 struct __prelim_ref
*ref
,
261 struct ulist
*parents
,
262 const u64
*extent_item_pos
)
264 struct btrfs_path
*path
;
265 struct btrfs_root
*root
;
266 struct btrfs_key root_key
;
267 struct extent_buffer
*eb
;
270 int level
= ref
->level
;
272 path
= btrfs_alloc_path();
275 path
->search_commit_root
= !!search_commit_root
;
277 root_key
.objectid
= ref
->root_id
;
278 root_key
.type
= BTRFS_ROOT_ITEM_KEY
;
279 root_key
.offset
= (u64
)-1;
280 root
= btrfs_read_fs_root_no_name(fs_info
, &root_key
);
286 root_level
= btrfs_old_root_level(root
, time_seq
);
288 if (root_level
+ 1 == level
)
291 path
->lowest_level
= level
;
292 ret
= btrfs_search_old_slot(root
, &ref
->key_for_search
, path
, time_seq
);
293 pr_debug("search slot in root %llu (level %d, ref count %d) returned "
294 "%d for key (%llu %u %llu)\n",
295 (unsigned long long)ref
->root_id
, level
, ref
->count
, ret
,
296 (unsigned long long)ref
->key_for_search
.objectid
,
297 ref
->key_for_search
.type
,
298 (unsigned long long)ref
->key_for_search
.offset
);
302 eb
= path
->nodes
[level
];
310 eb
= path
->nodes
[level
];
313 ret
= add_all_parents(root
, path
, parents
, level
, &ref
->key_for_search
,
314 time_seq
, ref
->wanted_disk_byte
,
317 btrfs_free_path(path
);
322 * resolve all indirect backrefs from the list
324 static int __resolve_indirect_refs(struct btrfs_fs_info
*fs_info
,
325 int search_commit_root
, u64 time_seq
,
326 struct list_head
*head
,
327 const u64
*extent_item_pos
)
331 struct __prelim_ref
*ref
;
332 struct __prelim_ref
*ref_safe
;
333 struct __prelim_ref
*new_ref
;
334 struct ulist
*parents
;
335 struct ulist_node
*node
;
336 struct ulist_iterator uiter
;
338 parents
= ulist_alloc(GFP_NOFS
);
343 * _safe allows us to insert directly after the current item without
344 * iterating over the newly inserted items.
345 * we're also allowed to re-assign ref during iteration.
347 list_for_each_entry_safe(ref
, ref_safe
, head
, list
) {
348 if (ref
->parent
) /* already direct */
352 err
= __resolve_indirect_ref(fs_info
, search_commit_root
,
353 time_seq
, ref
, parents
,
358 /* we put the first parent into the ref at hand */
359 ULIST_ITER_INIT(&uiter
);
360 node
= ulist_next(parents
, &uiter
);
361 ref
->parent
= node
? node
->val
: 0;
362 ref
->inode_list
= node
?
363 (struct extent_inode_elem
*)(uintptr_t)node
->aux
: 0;
365 /* additional parents require new refs being added here */
366 while ((node
= ulist_next(parents
, &uiter
))) {
367 new_ref
= kmalloc(sizeof(*new_ref
), GFP_NOFS
);
372 memcpy(new_ref
, ref
, sizeof(*ref
));
373 new_ref
->parent
= node
->val
;
374 new_ref
->inode_list
= (struct extent_inode_elem
*)
375 (uintptr_t)node
->aux
;
376 list_add(&new_ref
->list
, &ref
->list
);
378 ulist_reinit(parents
);
385 static inline int ref_for_same_block(struct __prelim_ref
*ref1
,
386 struct __prelim_ref
*ref2
)
388 if (ref1
->level
!= ref2
->level
)
390 if (ref1
->root_id
!= ref2
->root_id
)
392 if (ref1
->key_for_search
.type
!= ref2
->key_for_search
.type
)
394 if (ref1
->key_for_search
.objectid
!= ref2
->key_for_search
.objectid
)
396 if (ref1
->key_for_search
.offset
!= ref2
->key_for_search
.offset
)
398 if (ref1
->parent
!= ref2
->parent
)
405 * read tree blocks and add keys where required.
407 static int __add_missing_keys(struct btrfs_fs_info
*fs_info
,
408 struct list_head
*head
)
410 struct list_head
*pos
;
411 struct extent_buffer
*eb
;
413 list_for_each(pos
, head
) {
414 struct __prelim_ref
*ref
;
415 ref
= list_entry(pos
, struct __prelim_ref
, list
);
419 if (ref
->key_for_search
.type
)
421 BUG_ON(!ref
->wanted_disk_byte
);
422 eb
= read_tree_block(fs_info
->tree_root
, ref
->wanted_disk_byte
,
423 fs_info
->tree_root
->leafsize
, 0);
425 btrfs_tree_read_lock(eb
);
426 if (btrfs_header_level(eb
) == 0)
427 btrfs_item_key_to_cpu(eb
, &ref
->key_for_search
, 0);
429 btrfs_node_key_to_cpu(eb
, &ref
->key_for_search
, 0);
430 btrfs_tree_read_unlock(eb
);
431 free_extent_buffer(eb
);
437 * merge two lists of backrefs and adjust counts accordingly
439 * mode = 1: merge identical keys, if key is set
440 * FIXME: if we add more keys in __add_prelim_ref, we can merge more here.
441 * additionally, we could even add a key range for the blocks we
442 * looked into to merge even more (-> replace unresolved refs by those
444 * mode = 2: merge identical parents
446 static int __merge_refs(struct list_head
*head
, int mode
)
448 struct list_head
*pos1
;
450 list_for_each(pos1
, head
) {
451 struct list_head
*n2
;
452 struct list_head
*pos2
;
453 struct __prelim_ref
*ref1
;
455 ref1
= list_entry(pos1
, struct __prelim_ref
, list
);
457 for (pos2
= pos1
->next
, n2
= pos2
->next
; pos2
!= head
;
458 pos2
= n2
, n2
= pos2
->next
) {
459 struct __prelim_ref
*ref2
;
460 struct __prelim_ref
*xchg
;
461 struct extent_inode_elem
*eie
;
463 ref2
= list_entry(pos2
, struct __prelim_ref
, list
);
466 if (!ref_for_same_block(ref1
, ref2
))
468 if (!ref1
->parent
&& ref2
->parent
) {
474 if (ref1
->parent
!= ref2
->parent
)
478 eie
= ref1
->inode_list
;
479 while (eie
&& eie
->next
)
482 eie
->next
= ref2
->inode_list
;
484 ref1
->inode_list
= ref2
->inode_list
;
485 ref1
->count
+= ref2
->count
;
487 list_del(&ref2
->list
);
496 * add all currently queued delayed refs from this head whose seq nr is
497 * smaller or equal that seq to the list
499 static int __add_delayed_refs(struct btrfs_delayed_ref_head
*head
, u64 seq
,
500 struct list_head
*prefs
)
502 struct btrfs_delayed_extent_op
*extent_op
= head
->extent_op
;
503 struct rb_node
*n
= &head
->node
.rb_node
;
504 struct btrfs_key key
;
505 struct btrfs_key op_key
= {0};
509 if (extent_op
&& extent_op
->update_key
)
510 btrfs_disk_key_to_cpu(&op_key
, &extent_op
->key
);
512 while ((n
= rb_prev(n
))) {
513 struct btrfs_delayed_ref_node
*node
;
514 node
= rb_entry(n
, struct btrfs_delayed_ref_node
,
516 if (node
->bytenr
!= head
->node
.bytenr
)
518 WARN_ON(node
->is_head
);
523 switch (node
->action
) {
524 case BTRFS_ADD_DELAYED_EXTENT
:
525 case BTRFS_UPDATE_DELAYED_HEAD
:
528 case BTRFS_ADD_DELAYED_REF
:
531 case BTRFS_DROP_DELAYED_REF
:
537 switch (node
->type
) {
538 case BTRFS_TREE_BLOCK_REF_KEY
: {
539 struct btrfs_delayed_tree_ref
*ref
;
541 ref
= btrfs_delayed_node_to_tree_ref(node
);
542 ret
= __add_prelim_ref(prefs
, ref
->root
, &op_key
,
543 ref
->level
+ 1, 0, node
->bytenr
,
544 node
->ref_mod
* sgn
);
547 case BTRFS_SHARED_BLOCK_REF_KEY
: {
548 struct btrfs_delayed_tree_ref
*ref
;
550 ref
= btrfs_delayed_node_to_tree_ref(node
);
551 ret
= __add_prelim_ref(prefs
, ref
->root
, NULL
,
552 ref
->level
+ 1, ref
->parent
,
554 node
->ref_mod
* sgn
);
557 case BTRFS_EXTENT_DATA_REF_KEY
: {
558 struct btrfs_delayed_data_ref
*ref
;
559 ref
= btrfs_delayed_node_to_data_ref(node
);
561 key
.objectid
= ref
->objectid
;
562 key
.type
= BTRFS_EXTENT_DATA_KEY
;
563 key
.offset
= ref
->offset
;
564 ret
= __add_prelim_ref(prefs
, ref
->root
, &key
, 0, 0,
566 node
->ref_mod
* sgn
);
569 case BTRFS_SHARED_DATA_REF_KEY
: {
570 struct btrfs_delayed_data_ref
*ref
;
572 ref
= btrfs_delayed_node_to_data_ref(node
);
574 key
.objectid
= ref
->objectid
;
575 key
.type
= BTRFS_EXTENT_DATA_KEY
;
576 key
.offset
= ref
->offset
;
577 ret
= __add_prelim_ref(prefs
, ref
->root
, &key
, 0,
578 ref
->parent
, node
->bytenr
,
579 node
->ref_mod
* sgn
);
592 * add all inline backrefs for bytenr to the list
594 static int __add_inline_refs(struct btrfs_fs_info
*fs_info
,
595 struct btrfs_path
*path
, u64 bytenr
,
596 int *info_level
, struct list_head
*prefs
)
600 struct extent_buffer
*leaf
;
601 struct btrfs_key key
;
604 struct btrfs_extent_item
*ei
;
609 * enumerate all inline refs
611 leaf
= path
->nodes
[0];
612 slot
= path
->slots
[0];
614 item_size
= btrfs_item_size_nr(leaf
, slot
);
615 BUG_ON(item_size
< sizeof(*ei
));
617 ei
= btrfs_item_ptr(leaf
, slot
, struct btrfs_extent_item
);
618 flags
= btrfs_extent_flags(leaf
, ei
);
620 ptr
= (unsigned long)(ei
+ 1);
621 end
= (unsigned long)ei
+ item_size
;
623 if (flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
) {
624 struct btrfs_tree_block_info
*info
;
626 info
= (struct btrfs_tree_block_info
*)ptr
;
627 *info_level
= btrfs_tree_block_level(leaf
, info
);
628 ptr
+= sizeof(struct btrfs_tree_block_info
);
631 BUG_ON(!(flags
& BTRFS_EXTENT_FLAG_DATA
));
635 struct btrfs_extent_inline_ref
*iref
;
639 iref
= (struct btrfs_extent_inline_ref
*)ptr
;
640 type
= btrfs_extent_inline_ref_type(leaf
, iref
);
641 offset
= btrfs_extent_inline_ref_offset(leaf
, iref
);
644 case BTRFS_SHARED_BLOCK_REF_KEY
:
645 ret
= __add_prelim_ref(prefs
, 0, NULL
,
646 *info_level
+ 1, offset
,
649 case BTRFS_SHARED_DATA_REF_KEY
: {
650 struct btrfs_shared_data_ref
*sdref
;
653 sdref
= (struct btrfs_shared_data_ref
*)(iref
+ 1);
654 count
= btrfs_shared_data_ref_count(leaf
, sdref
);
655 ret
= __add_prelim_ref(prefs
, 0, NULL
, 0, offset
,
659 case BTRFS_TREE_BLOCK_REF_KEY
:
660 ret
= __add_prelim_ref(prefs
, offset
, NULL
,
664 case BTRFS_EXTENT_DATA_REF_KEY
: {
665 struct btrfs_extent_data_ref
*dref
;
669 dref
= (struct btrfs_extent_data_ref
*)(&iref
->offset
);
670 count
= btrfs_extent_data_ref_count(leaf
, dref
);
671 key
.objectid
= btrfs_extent_data_ref_objectid(leaf
,
673 key
.type
= BTRFS_EXTENT_DATA_KEY
;
674 key
.offset
= btrfs_extent_data_ref_offset(leaf
, dref
);
675 root
= btrfs_extent_data_ref_root(leaf
, dref
);
676 ret
= __add_prelim_ref(prefs
, root
, &key
, 0, 0,
684 ptr
+= btrfs_extent_inline_ref_size(type
);
691 * add all non-inline backrefs for bytenr to the list
693 static int __add_keyed_refs(struct btrfs_fs_info
*fs_info
,
694 struct btrfs_path
*path
, u64 bytenr
,
695 int info_level
, struct list_head
*prefs
)
697 struct btrfs_root
*extent_root
= fs_info
->extent_root
;
700 struct extent_buffer
*leaf
;
701 struct btrfs_key key
;
704 ret
= btrfs_next_item(extent_root
, path
);
712 slot
= path
->slots
[0];
713 leaf
= path
->nodes
[0];
714 btrfs_item_key_to_cpu(leaf
, &key
, slot
);
716 if (key
.objectid
!= bytenr
)
718 if (key
.type
< BTRFS_TREE_BLOCK_REF_KEY
)
720 if (key
.type
> BTRFS_SHARED_DATA_REF_KEY
)
724 case BTRFS_SHARED_BLOCK_REF_KEY
:
725 ret
= __add_prelim_ref(prefs
, 0, NULL
,
726 info_level
+ 1, key
.offset
,
729 case BTRFS_SHARED_DATA_REF_KEY
: {
730 struct btrfs_shared_data_ref
*sdref
;
733 sdref
= btrfs_item_ptr(leaf
, slot
,
734 struct btrfs_shared_data_ref
);
735 count
= btrfs_shared_data_ref_count(leaf
, sdref
);
736 ret
= __add_prelim_ref(prefs
, 0, NULL
, 0, key
.offset
,
740 case BTRFS_TREE_BLOCK_REF_KEY
:
741 ret
= __add_prelim_ref(prefs
, key
.offset
, NULL
,
745 case BTRFS_EXTENT_DATA_REF_KEY
: {
746 struct btrfs_extent_data_ref
*dref
;
750 dref
= btrfs_item_ptr(leaf
, slot
,
751 struct btrfs_extent_data_ref
);
752 count
= btrfs_extent_data_ref_count(leaf
, dref
);
753 key
.objectid
= btrfs_extent_data_ref_objectid(leaf
,
755 key
.type
= BTRFS_EXTENT_DATA_KEY
;
756 key
.offset
= btrfs_extent_data_ref_offset(leaf
, dref
);
757 root
= btrfs_extent_data_ref_root(leaf
, dref
);
758 ret
= __add_prelim_ref(prefs
, root
, &key
, 0, 0,
772 * this adds all existing backrefs (inline backrefs, backrefs and delayed
773 * refs) for the given bytenr to the refs list, merges duplicates and resolves
774 * indirect refs to their parent bytenr.
775 * When roots are found, they're added to the roots list
777 * FIXME some caching might speed things up
779 static int find_parent_nodes(struct btrfs_trans_handle
*trans
,
780 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
781 u64 time_seq
, struct ulist
*refs
,
782 struct ulist
*roots
, const u64
*extent_item_pos
)
784 struct btrfs_key key
;
785 struct btrfs_path
*path
;
786 struct btrfs_delayed_ref_root
*delayed_refs
= NULL
;
787 struct btrfs_delayed_ref_head
*head
;
790 int search_commit_root
= (trans
== BTRFS_BACKREF_SEARCH_COMMIT_ROOT
);
791 struct list_head prefs_delayed
;
792 struct list_head prefs
;
793 struct __prelim_ref
*ref
;
795 INIT_LIST_HEAD(&prefs
);
796 INIT_LIST_HEAD(&prefs_delayed
);
798 key
.objectid
= bytenr
;
799 key
.type
= BTRFS_EXTENT_ITEM_KEY
;
800 key
.offset
= (u64
)-1;
802 path
= btrfs_alloc_path();
805 path
->search_commit_root
= !!search_commit_root
;
808 * grab both a lock on the path and a lock on the delayed ref head.
809 * We need both to get a consistent picture of how the refs look
810 * at a specified point in time
815 ret
= btrfs_search_slot(trans
, fs_info
->extent_root
, &key
, path
, 0, 0);
820 if (trans
!= BTRFS_BACKREF_SEARCH_COMMIT_ROOT
) {
822 * look if there are updates for this ref queued and lock the
825 delayed_refs
= &trans
->transaction
->delayed_refs
;
826 spin_lock(&delayed_refs
->lock
);
827 head
= btrfs_find_delayed_ref_head(trans
, bytenr
);
829 if (!mutex_trylock(&head
->mutex
)) {
830 atomic_inc(&head
->node
.refs
);
831 spin_unlock(&delayed_refs
->lock
);
833 btrfs_release_path(path
);
836 * Mutex was contended, block until it's
837 * released and try again
839 mutex_lock(&head
->mutex
);
840 mutex_unlock(&head
->mutex
);
841 btrfs_put_delayed_ref(&head
->node
);
844 ret
= __add_delayed_refs(head
, time_seq
,
846 mutex_unlock(&head
->mutex
);
848 spin_unlock(&delayed_refs
->lock
);
852 spin_unlock(&delayed_refs
->lock
);
855 if (path
->slots
[0]) {
856 struct extent_buffer
*leaf
;
860 leaf
= path
->nodes
[0];
861 slot
= path
->slots
[0];
862 btrfs_item_key_to_cpu(leaf
, &key
, slot
);
863 if (key
.objectid
== bytenr
&&
864 key
.type
== BTRFS_EXTENT_ITEM_KEY
) {
865 ret
= __add_inline_refs(fs_info
, path
, bytenr
,
866 &info_level
, &prefs
);
869 ret
= __add_keyed_refs(fs_info
, path
, bytenr
,
875 btrfs_release_path(path
);
877 list_splice_init(&prefs_delayed
, &prefs
);
879 ret
= __add_missing_keys(fs_info
, &prefs
);
883 ret
= __merge_refs(&prefs
, 1);
887 ret
= __resolve_indirect_refs(fs_info
, search_commit_root
, time_seq
,
888 &prefs
, extent_item_pos
);
892 ret
= __merge_refs(&prefs
, 2);
896 while (!list_empty(&prefs
)) {
897 ref
= list_first_entry(&prefs
, struct __prelim_ref
, list
);
898 list_del(&ref
->list
);
899 WARN_ON(ref
->count
< 0);
900 if (ref
->count
&& ref
->root_id
&& ref
->parent
== 0) {
901 /* no parent == root of tree */
902 ret
= ulist_add(roots
, ref
->root_id
, 0, GFP_NOFS
);
905 if (ref
->count
&& ref
->parent
) {
906 struct extent_inode_elem
*eie
= NULL
;
907 if (extent_item_pos
&& !ref
->inode_list
) {
909 struct extent_buffer
*eb
;
910 bsz
= btrfs_level_size(fs_info
->extent_root
,
912 eb
= read_tree_block(fs_info
->extent_root
,
913 ref
->parent
, bsz
, 0);
915 ret
= find_extent_in_eb(eb
, bytenr
,
916 *extent_item_pos
, &eie
);
917 ref
->inode_list
= eie
;
918 free_extent_buffer(eb
);
920 ret
= ulist_add_merge(refs
, ref
->parent
,
921 (uintptr_t)ref
->inode_list
,
922 (u64
*)&eie
, GFP_NOFS
);
923 if (!ret
&& extent_item_pos
) {
925 * we've recorded that parent, so we must extend
926 * its inode list here
931 eie
->next
= ref
->inode_list
;
939 btrfs_free_path(path
);
940 while (!list_empty(&prefs
)) {
941 ref
= list_first_entry(&prefs
, struct __prelim_ref
, list
);
942 list_del(&ref
->list
);
945 while (!list_empty(&prefs_delayed
)) {
946 ref
= list_first_entry(&prefs_delayed
, struct __prelim_ref
,
948 list_del(&ref
->list
);
955 static void free_leaf_list(struct ulist
*blocks
)
957 struct ulist_node
*node
= NULL
;
958 struct extent_inode_elem
*eie
;
959 struct extent_inode_elem
*eie_next
;
960 struct ulist_iterator uiter
;
962 ULIST_ITER_INIT(&uiter
);
963 while ((node
= ulist_next(blocks
, &uiter
))) {
966 eie
= (struct extent_inode_elem
*)(uintptr_t)node
->aux
;
967 for (; eie
; eie
= eie_next
) {
968 eie_next
= eie
->next
;
978 * Finds all leafs with a reference to the specified combination of bytenr and
979 * offset. key_list_head will point to a list of corresponding keys (caller must
980 * free each list element). The leafs will be stored in the leafs ulist, which
981 * must be freed with ulist_free.
983 * returns 0 on success, <0 on error
985 static int btrfs_find_all_leafs(struct btrfs_trans_handle
*trans
,
986 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
987 u64 time_seq
, struct ulist
**leafs
,
988 const u64
*extent_item_pos
)
993 tmp
= ulist_alloc(GFP_NOFS
);
996 *leafs
= ulist_alloc(GFP_NOFS
);
1002 ret
= find_parent_nodes(trans
, fs_info
, bytenr
,
1003 time_seq
, *leafs
, tmp
, extent_item_pos
);
1006 if (ret
< 0 && ret
!= -ENOENT
) {
1007 free_leaf_list(*leafs
);
1015 * walk all backrefs for a given extent to find all roots that reference this
1016 * extent. Walking a backref means finding all extents that reference this
1017 * extent and in turn walk the backrefs of those, too. Naturally this is a
1018 * recursive process, but here it is implemented in an iterative fashion: We
1019 * find all referencing extents for the extent in question and put them on a
1020 * list. In turn, we find all referencing extents for those, further appending
1021 * to the list. The way we iterate the list allows adding more elements after
1022 * the current while iterating. The process stops when we reach the end of the
1023 * list. Found roots are added to the roots list.
1025 * returns 0 on success, < 0 on error.
1027 int btrfs_find_all_roots(struct btrfs_trans_handle
*trans
,
1028 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
1029 u64 time_seq
, struct ulist
**roots
)
1032 struct ulist_node
*node
= NULL
;
1033 struct ulist_iterator uiter
;
1036 tmp
= ulist_alloc(GFP_NOFS
);
1039 *roots
= ulist_alloc(GFP_NOFS
);
1045 ULIST_ITER_INIT(&uiter
);
1047 ret
= find_parent_nodes(trans
, fs_info
, bytenr
,
1048 time_seq
, tmp
, *roots
, NULL
);
1049 if (ret
< 0 && ret
!= -ENOENT
) {
1054 node
= ulist_next(tmp
, &uiter
);
1065 static int __inode_info(u64 inum
, u64 ioff
, u8 key_type
,
1066 struct btrfs_root
*fs_root
, struct btrfs_path
*path
,
1067 struct btrfs_key
*found_key
)
1070 struct btrfs_key key
;
1071 struct extent_buffer
*eb
;
1073 key
.type
= key_type
;
1074 key
.objectid
= inum
;
1077 ret
= btrfs_search_slot(NULL
, fs_root
, &key
, path
, 0, 0);
1081 eb
= path
->nodes
[0];
1082 if (ret
&& path
->slots
[0] >= btrfs_header_nritems(eb
)) {
1083 ret
= btrfs_next_leaf(fs_root
, path
);
1086 eb
= path
->nodes
[0];
1089 btrfs_item_key_to_cpu(eb
, found_key
, path
->slots
[0]);
1090 if (found_key
->type
!= key
.type
|| found_key
->objectid
!= key
.objectid
)
1097 * this makes the path point to (inum INODE_ITEM ioff)
1099 int inode_item_info(u64 inum
, u64 ioff
, struct btrfs_root
*fs_root
,
1100 struct btrfs_path
*path
)
1102 struct btrfs_key key
;
1103 return __inode_info(inum
, ioff
, BTRFS_INODE_ITEM_KEY
, fs_root
, path
,
1107 static int inode_ref_info(u64 inum
, u64 ioff
, struct btrfs_root
*fs_root
,
1108 struct btrfs_path
*path
,
1109 struct btrfs_key
*found_key
)
1111 return __inode_info(inum
, ioff
, BTRFS_INODE_REF_KEY
, fs_root
, path
,
1115 int btrfs_find_one_extref(struct btrfs_root
*root
, u64 inode_objectid
,
1116 u64 start_off
, struct btrfs_path
*path
,
1117 struct btrfs_inode_extref
**ret_extref
,
1121 struct btrfs_key key
;
1122 struct btrfs_key found_key
;
1123 struct btrfs_inode_extref
*extref
;
1124 struct extent_buffer
*leaf
;
1127 key
.objectid
= inode_objectid
;
1128 btrfs_set_key_type(&key
, BTRFS_INODE_EXTREF_KEY
);
1129 key
.offset
= start_off
;
1131 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
1136 leaf
= path
->nodes
[0];
1137 slot
= path
->slots
[0];
1138 if (slot
>= btrfs_header_nritems(leaf
)) {
1140 * If the item at offset is not found,
1141 * btrfs_search_slot will point us to the slot
1142 * where it should be inserted. In our case
1143 * that will be the slot directly before the
1144 * next INODE_REF_KEY_V2 item. In the case
1145 * that we're pointing to the last slot in a
1146 * leaf, we must move one leaf over.
1148 ret
= btrfs_next_leaf(root
, path
);
1157 btrfs_item_key_to_cpu(leaf
, &found_key
, slot
);
1160 * Check that we're still looking at an extended ref key for
1161 * this particular objectid. If we have different
1162 * objectid or type then there are no more to be found
1163 * in the tree and we can exit.
1166 if (found_key
.objectid
!= inode_objectid
)
1168 if (btrfs_key_type(&found_key
) != BTRFS_INODE_EXTREF_KEY
)
1172 ptr
= btrfs_item_ptr_offset(leaf
, path
->slots
[0]);
1173 extref
= (struct btrfs_inode_extref
*)ptr
;
1174 *ret_extref
= extref
;
1176 *found_off
= found_key
.offset
;
1183 char *btrfs_ref_to_path(struct btrfs_root
*fs_root
, struct btrfs_path
*path
,
1184 u32 name_len
, unsigned long name_off
,
1185 struct extent_buffer
*eb_in
, u64 parent
,
1186 char *dest
, u32 size
)
1191 s64 bytes_left
= ((s64
)size
) - 1;
1192 struct extent_buffer
*eb
= eb_in
;
1193 struct btrfs_key found_key
;
1194 int leave_spinning
= path
->leave_spinning
;
1195 struct btrfs_inode_ref
*iref
;
1197 if (bytes_left
>= 0)
1198 dest
[bytes_left
] = '\0';
1200 path
->leave_spinning
= 1;
1202 bytes_left
-= name_len
;
1203 if (bytes_left
>= 0)
1204 read_extent_buffer(eb
, dest
+ bytes_left
,
1205 name_off
, name_len
);
1207 btrfs_tree_read_unlock_blocking(eb
);
1208 free_extent_buffer(eb
);
1210 ret
= inode_ref_info(parent
, 0, fs_root
, path
, &found_key
);
1216 next_inum
= found_key
.offset
;
1218 /* regular exit ahead */
1219 if (parent
== next_inum
)
1222 slot
= path
->slots
[0];
1223 eb
= path
->nodes
[0];
1224 /* make sure we can use eb after releasing the path */
1226 atomic_inc(&eb
->refs
);
1227 btrfs_tree_read_lock(eb
);
1228 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1230 btrfs_release_path(path
);
1231 iref
= btrfs_item_ptr(eb
, slot
, struct btrfs_inode_ref
);
1233 name_len
= btrfs_inode_ref_name_len(eb
, iref
);
1234 name_off
= (unsigned long)(iref
+ 1);
1238 if (bytes_left
>= 0)
1239 dest
[bytes_left
] = '/';
1242 btrfs_release_path(path
);
1243 path
->leave_spinning
= leave_spinning
;
1246 return ERR_PTR(ret
);
1248 return dest
+ bytes_left
;
1252 * this iterates to turn a btrfs_inode_ref into a full filesystem path. elements
1253 * of the path are separated by '/' and the path is guaranteed to be
1254 * 0-terminated. the path is only given within the current file system.
1255 * Therefore, it never starts with a '/'. the caller is responsible to provide
1256 * "size" bytes in "dest". the dest buffer will be filled backwards. finally,
1257 * the start point of the resulting string is returned. this pointer is within
1259 * in case the path buffer would overflow, the pointer is decremented further
1260 * as if output was written to the buffer, though no more output is actually
1261 * generated. that way, the caller can determine how much space would be
1262 * required for the path to fit into the buffer. in that case, the returned
1263 * value will be smaller than dest. callers must check this!
1265 char *btrfs_iref_to_path(struct btrfs_root
*fs_root
,
1266 struct btrfs_path
*path
,
1267 struct btrfs_inode_ref
*iref
,
1268 struct extent_buffer
*eb_in
, u64 parent
,
1269 char *dest
, u32 size
)
1271 return btrfs_ref_to_path(fs_root
, path
,
1272 btrfs_inode_ref_name_len(eb_in
, iref
),
1273 (unsigned long)(iref
+ 1),
1274 eb_in
, parent
, dest
, size
);
1278 * this makes the path point to (logical EXTENT_ITEM *)
1279 * returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for
1280 * tree blocks and <0 on error.
1282 int extent_from_logical(struct btrfs_fs_info
*fs_info
, u64 logical
,
1283 struct btrfs_path
*path
, struct btrfs_key
*found_key
,
1289 struct extent_buffer
*eb
;
1290 struct btrfs_extent_item
*ei
;
1291 struct btrfs_key key
;
1293 key
.type
= BTRFS_EXTENT_ITEM_KEY
;
1294 key
.objectid
= logical
;
1295 key
.offset
= (u64
)-1;
1297 ret
= btrfs_search_slot(NULL
, fs_info
->extent_root
, &key
, path
, 0, 0);
1300 ret
= btrfs_previous_item(fs_info
->extent_root
, path
,
1301 0, BTRFS_EXTENT_ITEM_KEY
);
1305 btrfs_item_key_to_cpu(path
->nodes
[0], found_key
, path
->slots
[0]);
1306 if (found_key
->type
!= BTRFS_EXTENT_ITEM_KEY
||
1307 found_key
->objectid
> logical
||
1308 found_key
->objectid
+ found_key
->offset
<= logical
) {
1309 pr_debug("logical %llu is not within any extent\n",
1310 (unsigned long long)logical
);
1314 eb
= path
->nodes
[0];
1315 item_size
= btrfs_item_size_nr(eb
, path
->slots
[0]);
1316 BUG_ON(item_size
< sizeof(*ei
));
1318 ei
= btrfs_item_ptr(eb
, path
->slots
[0], struct btrfs_extent_item
);
1319 flags
= btrfs_extent_flags(eb
, ei
);
1321 pr_debug("logical %llu is at position %llu within the extent (%llu "
1322 "EXTENT_ITEM %llu) flags %#llx size %u\n",
1323 (unsigned long long)logical
,
1324 (unsigned long long)(logical
- found_key
->objectid
),
1325 (unsigned long long)found_key
->objectid
,
1326 (unsigned long long)found_key
->offset
,
1327 (unsigned long long)flags
, item_size
);
1329 WARN_ON(!flags_ret
);
1331 if (flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
)
1332 *flags_ret
= BTRFS_EXTENT_FLAG_TREE_BLOCK
;
1333 else if (flags
& BTRFS_EXTENT_FLAG_DATA
)
1334 *flags_ret
= BTRFS_EXTENT_FLAG_DATA
;
1344 * helper function to iterate extent inline refs. ptr must point to a 0 value
1345 * for the first call and may be modified. it is used to track state.
1346 * if more refs exist, 0 is returned and the next call to
1347 * __get_extent_inline_ref must pass the modified ptr parameter to get the
1348 * next ref. after the last ref was processed, 1 is returned.
1349 * returns <0 on error
1351 static int __get_extent_inline_ref(unsigned long *ptr
, struct extent_buffer
*eb
,
1352 struct btrfs_extent_item
*ei
, u32 item_size
,
1353 struct btrfs_extent_inline_ref
**out_eiref
,
1358 struct btrfs_tree_block_info
*info
;
1362 flags
= btrfs_extent_flags(eb
, ei
);
1363 if (flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
) {
1364 info
= (struct btrfs_tree_block_info
*)(ei
+ 1);
1366 (struct btrfs_extent_inline_ref
*)(info
+ 1);
1368 *out_eiref
= (struct btrfs_extent_inline_ref
*)(ei
+ 1);
1370 *ptr
= (unsigned long)*out_eiref
;
1371 if ((void *)*ptr
>= (void *)ei
+ item_size
)
1375 end
= (unsigned long)ei
+ item_size
;
1376 *out_eiref
= (struct btrfs_extent_inline_ref
*)*ptr
;
1377 *out_type
= btrfs_extent_inline_ref_type(eb
, *out_eiref
);
1379 *ptr
+= btrfs_extent_inline_ref_size(*out_type
);
1380 WARN_ON(*ptr
> end
);
1382 return 1; /* last */
1388 * reads the tree block backref for an extent. tree level and root are returned
1389 * through out_level and out_root. ptr must point to a 0 value for the first
1390 * call and may be modified (see __get_extent_inline_ref comment).
1391 * returns 0 if data was provided, 1 if there was no more data to provide or
1394 int tree_backref_for_extent(unsigned long *ptr
, struct extent_buffer
*eb
,
1395 struct btrfs_extent_item
*ei
, u32 item_size
,
1396 u64
*out_root
, u8
*out_level
)
1400 struct btrfs_tree_block_info
*info
;
1401 struct btrfs_extent_inline_ref
*eiref
;
1403 if (*ptr
== (unsigned long)-1)
1407 ret
= __get_extent_inline_ref(ptr
, eb
, ei
, item_size
,
1412 if (type
== BTRFS_TREE_BLOCK_REF_KEY
||
1413 type
== BTRFS_SHARED_BLOCK_REF_KEY
)
1420 /* we can treat both ref types equally here */
1421 info
= (struct btrfs_tree_block_info
*)(ei
+ 1);
1422 *out_root
= btrfs_extent_inline_ref_offset(eb
, eiref
);
1423 *out_level
= btrfs_tree_block_level(eb
, info
);
1426 *ptr
= (unsigned long)-1;
1431 static int iterate_leaf_refs(struct extent_inode_elem
*inode_list
,
1432 u64 root
, u64 extent_item_objectid
,
1433 iterate_extent_inodes_t
*iterate
, void *ctx
)
1435 struct extent_inode_elem
*eie
;
1438 for (eie
= inode_list
; eie
; eie
= eie
->next
) {
1439 pr_debug("ref for %llu resolved, key (%llu EXTEND_DATA %llu), "
1440 "root %llu\n", extent_item_objectid
,
1441 eie
->inum
, eie
->offset
, root
);
1442 ret
= iterate(eie
->inum
, eie
->offset
, root
, ctx
);
1444 pr_debug("stopping iteration for %llu due to ret=%d\n",
1445 extent_item_objectid
, ret
);
1454 * calls iterate() for every inode that references the extent identified by
1455 * the given parameters.
1456 * when the iterator function returns a non-zero value, iteration stops.
1458 int iterate_extent_inodes(struct btrfs_fs_info
*fs_info
,
1459 u64 extent_item_objectid
, u64 extent_item_pos
,
1460 int search_commit_root
,
1461 iterate_extent_inodes_t
*iterate
, void *ctx
)
1464 struct list_head data_refs
= LIST_HEAD_INIT(data_refs
);
1465 struct list_head shared_refs
= LIST_HEAD_INIT(shared_refs
);
1466 struct btrfs_trans_handle
*trans
;
1467 struct ulist
*refs
= NULL
;
1468 struct ulist
*roots
= NULL
;
1469 struct ulist_node
*ref_node
= NULL
;
1470 struct ulist_node
*root_node
= NULL
;
1471 struct seq_list tree_mod_seq_elem
= {};
1472 struct ulist_iterator ref_uiter
;
1473 struct ulist_iterator root_uiter
;
1475 pr_debug("resolving all inodes for extent %llu\n",
1476 extent_item_objectid
);
1478 if (search_commit_root
) {
1479 trans
= BTRFS_BACKREF_SEARCH_COMMIT_ROOT
;
1481 trans
= btrfs_join_transaction(fs_info
->extent_root
);
1483 return PTR_ERR(trans
);
1484 btrfs_get_tree_mod_seq(fs_info
, &tree_mod_seq_elem
);
1487 ret
= btrfs_find_all_leafs(trans
, fs_info
, extent_item_objectid
,
1488 tree_mod_seq_elem
.seq
, &refs
,
1493 ULIST_ITER_INIT(&ref_uiter
);
1494 while (!ret
&& (ref_node
= ulist_next(refs
, &ref_uiter
))) {
1495 ret
= btrfs_find_all_roots(trans
, fs_info
, ref_node
->val
,
1496 tree_mod_seq_elem
.seq
, &roots
);
1499 ULIST_ITER_INIT(&root_uiter
);
1500 while (!ret
&& (root_node
= ulist_next(roots
, &root_uiter
))) {
1501 pr_debug("root %llu references leaf %llu, data list "
1502 "%#llx\n", root_node
->val
, ref_node
->val
,
1503 (long long)ref_node
->aux
);
1504 ret
= iterate_leaf_refs((struct extent_inode_elem
*)
1505 (uintptr_t)ref_node
->aux
,
1507 extent_item_objectid
,
1514 free_leaf_list(refs
);
1517 if (!search_commit_root
) {
1518 btrfs_put_tree_mod_seq(fs_info
, &tree_mod_seq_elem
);
1519 btrfs_end_transaction(trans
, fs_info
->extent_root
);
1525 int iterate_inodes_from_logical(u64 logical
, struct btrfs_fs_info
*fs_info
,
1526 struct btrfs_path
*path
,
1527 iterate_extent_inodes_t
*iterate
, void *ctx
)
1530 u64 extent_item_pos
;
1532 struct btrfs_key found_key
;
1533 int search_commit_root
= path
->search_commit_root
;
1535 ret
= extent_from_logical(fs_info
, logical
, path
, &found_key
, &flags
);
1536 btrfs_release_path(path
);
1539 if (flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
)
1542 extent_item_pos
= logical
- found_key
.objectid
;
1543 ret
= iterate_extent_inodes(fs_info
, found_key
.objectid
,
1544 extent_item_pos
, search_commit_root
,
1550 typedef int (iterate_irefs_t
)(u64 parent
, u32 name_len
, unsigned long name_off
,
1551 struct extent_buffer
*eb
, void *ctx
);
1553 static int iterate_inode_refs(u64 inum
, struct btrfs_root
*fs_root
,
1554 struct btrfs_path
*path
,
1555 iterate_irefs_t
*iterate
, void *ctx
)
1564 struct extent_buffer
*eb
;
1565 struct btrfs_item
*item
;
1566 struct btrfs_inode_ref
*iref
;
1567 struct btrfs_key found_key
;
1570 path
->leave_spinning
= 1;
1571 ret
= inode_ref_info(inum
, parent
? parent
+1 : 0, fs_root
, path
,
1576 ret
= found
? 0 : -ENOENT
;
1581 parent
= found_key
.offset
;
1582 slot
= path
->slots
[0];
1583 eb
= path
->nodes
[0];
1584 /* make sure we can use eb after releasing the path */
1585 atomic_inc(&eb
->refs
);
1586 btrfs_tree_read_lock(eb
);
1587 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1588 btrfs_release_path(path
);
1590 item
= btrfs_item_nr(eb
, slot
);
1591 iref
= btrfs_item_ptr(eb
, slot
, struct btrfs_inode_ref
);
1593 for (cur
= 0; cur
< btrfs_item_size(eb
, item
); cur
+= len
) {
1594 name_len
= btrfs_inode_ref_name_len(eb
, iref
);
1595 /* path must be released before calling iterate()! */
1596 pr_debug("following ref at offset %u for inode %llu in "
1598 (unsigned long long)found_key
.objectid
,
1599 (unsigned long long)fs_root
->objectid
);
1600 ret
= iterate(parent
, name_len
,
1601 (unsigned long)(iref
+ 1), eb
, ctx
);
1604 len
= sizeof(*iref
) + name_len
;
1605 iref
= (struct btrfs_inode_ref
*)((char *)iref
+ len
);
1607 btrfs_tree_read_unlock_blocking(eb
);
1608 free_extent_buffer(eb
);
1611 btrfs_release_path(path
);
1616 static int iterate_inode_extrefs(u64 inum
, struct btrfs_root
*fs_root
,
1617 struct btrfs_path
*path
,
1618 iterate_irefs_t
*iterate
, void *ctx
)
1625 struct extent_buffer
*eb
;
1626 struct btrfs_inode_extref
*extref
;
1627 struct extent_buffer
*leaf
;
1633 ret
= btrfs_find_one_extref(fs_root
, inum
, offset
, path
, &extref
,
1638 ret
= found
? 0 : -ENOENT
;
1643 slot
= path
->slots
[0];
1644 eb
= path
->nodes
[0];
1645 /* make sure we can use eb after releasing the path */
1646 atomic_inc(&eb
->refs
);
1648 btrfs_tree_read_lock(eb
);
1649 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1650 btrfs_release_path(path
);
1652 leaf
= path
->nodes
[0];
1653 item_size
= btrfs_item_size_nr(leaf
, path
->slots
[0]);
1654 ptr
= btrfs_item_ptr_offset(leaf
, path
->slots
[0]);
1657 while (cur_offset
< item_size
) {
1660 extref
= (struct btrfs_inode_extref
*)(ptr
+ cur_offset
);
1661 parent
= btrfs_inode_extref_parent(eb
, extref
);
1662 name_len
= btrfs_inode_extref_name_len(eb
, extref
);
1663 ret
= iterate(parent
, name_len
,
1664 (unsigned long)&extref
->name
, eb
, ctx
);
1668 cur_offset
+= btrfs_inode_extref_name_len(leaf
, extref
);
1669 cur_offset
+= sizeof(*extref
);
1671 btrfs_tree_read_unlock_blocking(eb
);
1672 free_extent_buffer(eb
);
1677 btrfs_release_path(path
);
1682 static int iterate_irefs(u64 inum
, struct btrfs_root
*fs_root
,
1683 struct btrfs_path
*path
, iterate_irefs_t
*iterate
,
1689 ret
= iterate_inode_refs(inum
, fs_root
, path
, iterate
, ctx
);
1692 else if (ret
!= -ENOENT
)
1695 ret
= iterate_inode_extrefs(inum
, fs_root
, path
, iterate
, ctx
);
1696 if (ret
== -ENOENT
&& found_refs
)
1703 * returns 0 if the path could be dumped (probably truncated)
1704 * returns <0 in case of an error
1706 static int inode_to_path(u64 inum
, u32 name_len
, unsigned long name_off
,
1707 struct extent_buffer
*eb
, void *ctx
)
1709 struct inode_fs_paths
*ipath
= ctx
;
1712 int i
= ipath
->fspath
->elem_cnt
;
1713 const int s_ptr
= sizeof(char *);
1716 bytes_left
= ipath
->fspath
->bytes_left
> s_ptr
?
1717 ipath
->fspath
->bytes_left
- s_ptr
: 0;
1719 fspath_min
= (char *)ipath
->fspath
->val
+ (i
+ 1) * s_ptr
;
1720 fspath
= btrfs_ref_to_path(ipath
->fs_root
, ipath
->btrfs_path
, name_len
,
1721 name_off
, eb
, inum
, fspath_min
, bytes_left
);
1723 return PTR_ERR(fspath
);
1725 if (fspath
> fspath_min
) {
1726 ipath
->fspath
->val
[i
] = (u64
)(unsigned long)fspath
;
1727 ++ipath
->fspath
->elem_cnt
;
1728 ipath
->fspath
->bytes_left
= fspath
- fspath_min
;
1730 ++ipath
->fspath
->elem_missed
;
1731 ipath
->fspath
->bytes_missing
+= fspath_min
- fspath
;
1732 ipath
->fspath
->bytes_left
= 0;
1739 * this dumps all file system paths to the inode into the ipath struct, provided
1740 * is has been created large enough. each path is zero-terminated and accessed
1741 * from ipath->fspath->val[i].
1742 * when it returns, there are ipath->fspath->elem_cnt number of paths available
1743 * in ipath->fspath->val[]. when the allocated space wasn't sufficient, the
1744 * number of missed paths in recored in ipath->fspath->elem_missed, otherwise,
1745 * it's zero. ipath->fspath->bytes_missing holds the number of bytes that would
1746 * have been needed to return all paths.
1748 int paths_from_inode(u64 inum
, struct inode_fs_paths
*ipath
)
1750 return iterate_irefs(inum
, ipath
->fs_root
, ipath
->btrfs_path
,
1751 inode_to_path
, ipath
);
1754 struct btrfs_data_container
*init_data_container(u32 total_bytes
)
1756 struct btrfs_data_container
*data
;
1759 alloc_bytes
= max_t(size_t, total_bytes
, sizeof(*data
));
1760 data
= vmalloc(alloc_bytes
);
1762 return ERR_PTR(-ENOMEM
);
1764 if (total_bytes
>= sizeof(*data
)) {
1765 data
->bytes_left
= total_bytes
- sizeof(*data
);
1766 data
->bytes_missing
= 0;
1768 data
->bytes_missing
= sizeof(*data
) - total_bytes
;
1769 data
->bytes_left
= 0;
1773 data
->elem_missed
= 0;
1779 * allocates space to return multiple file system paths for an inode.
1780 * total_bytes to allocate are passed, note that space usable for actual path
1781 * information will be total_bytes - sizeof(struct inode_fs_paths).
1782 * the returned pointer must be freed with free_ipath() in the end.
1784 struct inode_fs_paths
*init_ipath(s32 total_bytes
, struct btrfs_root
*fs_root
,
1785 struct btrfs_path
*path
)
1787 struct inode_fs_paths
*ifp
;
1788 struct btrfs_data_container
*fspath
;
1790 fspath
= init_data_container(total_bytes
);
1792 return (void *)fspath
;
1794 ifp
= kmalloc(sizeof(*ifp
), GFP_NOFS
);
1797 return ERR_PTR(-ENOMEM
);
1800 ifp
->btrfs_path
= path
;
1801 ifp
->fspath
= fspath
;
1802 ifp
->fs_root
= fs_root
;
1807 void free_ipath(struct inode_fs_paths
*ipath
)
1811 vfree(ipath
->fspath
);