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 struct btrfs_path
*path
, u64 time_seq
,
259 struct __prelim_ref
*ref
,
260 struct ulist
*parents
,
261 const u64
*extent_item_pos
)
263 struct btrfs_root
*root
;
264 struct btrfs_key root_key
;
265 struct extent_buffer
*eb
;
268 int level
= ref
->level
;
270 root_key
.objectid
= ref
->root_id
;
271 root_key
.type
= BTRFS_ROOT_ITEM_KEY
;
272 root_key
.offset
= (u64
)-1;
273 root
= btrfs_read_fs_root_no_name(fs_info
, &root_key
);
279 root_level
= btrfs_old_root_level(root
, time_seq
);
281 if (root_level
+ 1 == level
)
284 path
->lowest_level
= level
;
285 ret
= btrfs_search_old_slot(root
, &ref
->key_for_search
, path
, time_seq
);
286 pr_debug("search slot in root %llu (level %d, ref count %d) returned "
287 "%d for key (%llu %u %llu)\n",
288 (unsigned long long)ref
->root_id
, level
, ref
->count
, ret
,
289 (unsigned long long)ref
->key_for_search
.objectid
,
290 ref
->key_for_search
.type
,
291 (unsigned long long)ref
->key_for_search
.offset
);
295 eb
= path
->nodes
[level
];
303 eb
= path
->nodes
[level
];
306 ret
= add_all_parents(root
, path
, parents
, level
, &ref
->key_for_search
,
307 time_seq
, ref
->wanted_disk_byte
,
310 path
->lowest_level
= 0;
311 btrfs_release_path(path
);
316 * resolve all indirect backrefs from the list
318 static int __resolve_indirect_refs(struct btrfs_fs_info
*fs_info
,
319 struct btrfs_path
*path
, u64 time_seq
,
320 struct list_head
*head
,
321 const u64
*extent_item_pos
)
325 struct __prelim_ref
*ref
;
326 struct __prelim_ref
*ref_safe
;
327 struct __prelim_ref
*new_ref
;
328 struct ulist
*parents
;
329 struct ulist_node
*node
;
330 struct ulist_iterator uiter
;
332 parents
= ulist_alloc(GFP_NOFS
);
337 * _safe allows us to insert directly after the current item without
338 * iterating over the newly inserted items.
339 * we're also allowed to re-assign ref during iteration.
341 list_for_each_entry_safe(ref
, ref_safe
, head
, list
) {
342 if (ref
->parent
) /* already direct */
346 err
= __resolve_indirect_ref(fs_info
, path
, time_seq
, ref
,
347 parents
, extent_item_pos
);
353 /* we put the first parent into the ref at hand */
354 ULIST_ITER_INIT(&uiter
);
355 node
= ulist_next(parents
, &uiter
);
356 ref
->parent
= node
? node
->val
: 0;
357 ref
->inode_list
= node
?
358 (struct extent_inode_elem
*)(uintptr_t)node
->aux
: 0;
360 /* additional parents require new refs being added here */
361 while ((node
= ulist_next(parents
, &uiter
))) {
362 new_ref
= kmalloc(sizeof(*new_ref
), GFP_NOFS
);
367 memcpy(new_ref
, ref
, sizeof(*ref
));
368 new_ref
->parent
= node
->val
;
369 new_ref
->inode_list
= (struct extent_inode_elem
*)
370 (uintptr_t)node
->aux
;
371 list_add(&new_ref
->list
, &ref
->list
);
373 ulist_reinit(parents
);
380 static inline int ref_for_same_block(struct __prelim_ref
*ref1
,
381 struct __prelim_ref
*ref2
)
383 if (ref1
->level
!= ref2
->level
)
385 if (ref1
->root_id
!= ref2
->root_id
)
387 if (ref1
->key_for_search
.type
!= ref2
->key_for_search
.type
)
389 if (ref1
->key_for_search
.objectid
!= ref2
->key_for_search
.objectid
)
391 if (ref1
->key_for_search
.offset
!= ref2
->key_for_search
.offset
)
393 if (ref1
->parent
!= ref2
->parent
)
400 * read tree blocks and add keys where required.
402 static int __add_missing_keys(struct btrfs_fs_info
*fs_info
,
403 struct list_head
*head
)
405 struct list_head
*pos
;
406 struct extent_buffer
*eb
;
408 list_for_each(pos
, head
) {
409 struct __prelim_ref
*ref
;
410 ref
= list_entry(pos
, struct __prelim_ref
, list
);
414 if (ref
->key_for_search
.type
)
416 BUG_ON(!ref
->wanted_disk_byte
);
417 eb
= read_tree_block(fs_info
->tree_root
, ref
->wanted_disk_byte
,
418 fs_info
->tree_root
->leafsize
, 0);
419 if (!eb
|| !extent_buffer_uptodate(eb
)) {
420 free_extent_buffer(eb
);
423 btrfs_tree_read_lock(eb
);
424 if (btrfs_header_level(eb
) == 0)
425 btrfs_item_key_to_cpu(eb
, &ref
->key_for_search
, 0);
427 btrfs_node_key_to_cpu(eb
, &ref
->key_for_search
, 0);
428 btrfs_tree_read_unlock(eb
);
429 free_extent_buffer(eb
);
435 * merge two lists of backrefs and adjust counts accordingly
437 * mode = 1: merge identical keys, if key is set
438 * FIXME: if we add more keys in __add_prelim_ref, we can merge more here.
439 * additionally, we could even add a key range for the blocks we
440 * looked into to merge even more (-> replace unresolved refs by those
442 * mode = 2: merge identical parents
444 static void __merge_refs(struct list_head
*head
, int mode
)
446 struct list_head
*pos1
;
448 list_for_each(pos1
, head
) {
449 struct list_head
*n2
;
450 struct list_head
*pos2
;
451 struct __prelim_ref
*ref1
;
453 ref1
= list_entry(pos1
, struct __prelim_ref
, list
);
455 for (pos2
= pos1
->next
, n2
= pos2
->next
; pos2
!= head
;
456 pos2
= n2
, n2
= pos2
->next
) {
457 struct __prelim_ref
*ref2
;
458 struct __prelim_ref
*xchg
;
459 struct extent_inode_elem
*eie
;
461 ref2
= list_entry(pos2
, struct __prelim_ref
, list
);
464 if (!ref_for_same_block(ref1
, ref2
))
466 if (!ref1
->parent
&& ref2
->parent
) {
472 if (ref1
->parent
!= ref2
->parent
)
476 eie
= ref1
->inode_list
;
477 while (eie
&& eie
->next
)
480 eie
->next
= ref2
->inode_list
;
482 ref1
->inode_list
= ref2
->inode_list
;
483 ref1
->count
+= ref2
->count
;
485 list_del(&ref2
->list
);
493 * add all currently queued delayed refs from this head whose seq nr is
494 * smaller or equal that seq to the list
496 static int __add_delayed_refs(struct btrfs_delayed_ref_head
*head
, u64 seq
,
497 struct list_head
*prefs
)
499 struct btrfs_delayed_extent_op
*extent_op
= head
->extent_op
;
500 struct rb_node
*n
= &head
->node
.rb_node
;
501 struct btrfs_key key
;
502 struct btrfs_key op_key
= {0};
506 if (extent_op
&& extent_op
->update_key
)
507 btrfs_disk_key_to_cpu(&op_key
, &extent_op
->key
);
509 while ((n
= rb_prev(n
))) {
510 struct btrfs_delayed_ref_node
*node
;
511 node
= rb_entry(n
, struct btrfs_delayed_ref_node
,
513 if (node
->bytenr
!= head
->node
.bytenr
)
515 WARN_ON(node
->is_head
);
520 switch (node
->action
) {
521 case BTRFS_ADD_DELAYED_EXTENT
:
522 case BTRFS_UPDATE_DELAYED_HEAD
:
525 case BTRFS_ADD_DELAYED_REF
:
528 case BTRFS_DROP_DELAYED_REF
:
534 switch (node
->type
) {
535 case BTRFS_TREE_BLOCK_REF_KEY
: {
536 struct btrfs_delayed_tree_ref
*ref
;
538 ref
= btrfs_delayed_node_to_tree_ref(node
);
539 ret
= __add_prelim_ref(prefs
, ref
->root
, &op_key
,
540 ref
->level
+ 1, 0, node
->bytenr
,
541 node
->ref_mod
* sgn
);
544 case BTRFS_SHARED_BLOCK_REF_KEY
: {
545 struct btrfs_delayed_tree_ref
*ref
;
547 ref
= btrfs_delayed_node_to_tree_ref(node
);
548 ret
= __add_prelim_ref(prefs
, ref
->root
, NULL
,
549 ref
->level
+ 1, ref
->parent
,
551 node
->ref_mod
* sgn
);
554 case BTRFS_EXTENT_DATA_REF_KEY
: {
555 struct btrfs_delayed_data_ref
*ref
;
556 ref
= btrfs_delayed_node_to_data_ref(node
);
558 key
.objectid
= ref
->objectid
;
559 key
.type
= BTRFS_EXTENT_DATA_KEY
;
560 key
.offset
= ref
->offset
;
561 ret
= __add_prelim_ref(prefs
, ref
->root
, &key
, 0, 0,
563 node
->ref_mod
* sgn
);
566 case BTRFS_SHARED_DATA_REF_KEY
: {
567 struct btrfs_delayed_data_ref
*ref
;
569 ref
= btrfs_delayed_node_to_data_ref(node
);
571 key
.objectid
= ref
->objectid
;
572 key
.type
= BTRFS_EXTENT_DATA_KEY
;
573 key
.offset
= ref
->offset
;
574 ret
= __add_prelim_ref(prefs
, ref
->root
, &key
, 0,
575 ref
->parent
, node
->bytenr
,
576 node
->ref_mod
* sgn
);
590 * add all inline backrefs for bytenr to the list
592 static int __add_inline_refs(struct btrfs_fs_info
*fs_info
,
593 struct btrfs_path
*path
, u64 bytenr
,
594 int *info_level
, struct list_head
*prefs
)
598 struct extent_buffer
*leaf
;
599 struct btrfs_key key
;
600 struct btrfs_key found_key
;
603 struct btrfs_extent_item
*ei
;
608 * enumerate all inline refs
610 leaf
= path
->nodes
[0];
611 slot
= path
->slots
[0];
613 item_size
= btrfs_item_size_nr(leaf
, slot
);
614 BUG_ON(item_size
< sizeof(*ei
));
616 ei
= btrfs_item_ptr(leaf
, slot
, struct btrfs_extent_item
);
617 flags
= btrfs_extent_flags(leaf
, ei
);
618 btrfs_item_key_to_cpu(leaf
, &found_key
, slot
);
620 ptr
= (unsigned long)(ei
+ 1);
621 end
= (unsigned long)ei
+ item_size
;
623 if (found_key
.type
== BTRFS_EXTENT_ITEM_KEY
&&
624 flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
) {
625 struct btrfs_tree_block_info
*info
;
627 info
= (struct btrfs_tree_block_info
*)ptr
;
628 *info_level
= btrfs_tree_block_level(leaf
, info
);
629 ptr
+= sizeof(struct btrfs_tree_block_info
);
631 } else if (found_key
.type
== BTRFS_METADATA_ITEM_KEY
) {
632 *info_level
= found_key
.offset
;
634 BUG_ON(!(flags
& BTRFS_EXTENT_FLAG_DATA
));
638 struct btrfs_extent_inline_ref
*iref
;
642 iref
= (struct btrfs_extent_inline_ref
*)ptr
;
643 type
= btrfs_extent_inline_ref_type(leaf
, iref
);
644 offset
= btrfs_extent_inline_ref_offset(leaf
, iref
);
647 case BTRFS_SHARED_BLOCK_REF_KEY
:
648 ret
= __add_prelim_ref(prefs
, 0, NULL
,
649 *info_level
+ 1, offset
,
652 case BTRFS_SHARED_DATA_REF_KEY
: {
653 struct btrfs_shared_data_ref
*sdref
;
656 sdref
= (struct btrfs_shared_data_ref
*)(iref
+ 1);
657 count
= btrfs_shared_data_ref_count(leaf
, sdref
);
658 ret
= __add_prelim_ref(prefs
, 0, NULL
, 0, offset
,
662 case BTRFS_TREE_BLOCK_REF_KEY
:
663 ret
= __add_prelim_ref(prefs
, offset
, NULL
,
667 case BTRFS_EXTENT_DATA_REF_KEY
: {
668 struct btrfs_extent_data_ref
*dref
;
672 dref
= (struct btrfs_extent_data_ref
*)(&iref
->offset
);
673 count
= btrfs_extent_data_ref_count(leaf
, dref
);
674 key
.objectid
= btrfs_extent_data_ref_objectid(leaf
,
676 key
.type
= BTRFS_EXTENT_DATA_KEY
;
677 key
.offset
= btrfs_extent_data_ref_offset(leaf
, dref
);
678 root
= btrfs_extent_data_ref_root(leaf
, dref
);
679 ret
= __add_prelim_ref(prefs
, root
, &key
, 0, 0,
688 ptr
+= btrfs_extent_inline_ref_size(type
);
695 * add all non-inline backrefs for bytenr to the list
697 static int __add_keyed_refs(struct btrfs_fs_info
*fs_info
,
698 struct btrfs_path
*path
, u64 bytenr
,
699 int info_level
, struct list_head
*prefs
)
701 struct btrfs_root
*extent_root
= fs_info
->extent_root
;
704 struct extent_buffer
*leaf
;
705 struct btrfs_key key
;
708 ret
= btrfs_next_item(extent_root
, path
);
716 slot
= path
->slots
[0];
717 leaf
= path
->nodes
[0];
718 btrfs_item_key_to_cpu(leaf
, &key
, slot
);
720 if (key
.objectid
!= bytenr
)
722 if (key
.type
< BTRFS_TREE_BLOCK_REF_KEY
)
724 if (key
.type
> BTRFS_SHARED_DATA_REF_KEY
)
728 case BTRFS_SHARED_BLOCK_REF_KEY
:
729 ret
= __add_prelim_ref(prefs
, 0, NULL
,
730 info_level
+ 1, key
.offset
,
733 case BTRFS_SHARED_DATA_REF_KEY
: {
734 struct btrfs_shared_data_ref
*sdref
;
737 sdref
= btrfs_item_ptr(leaf
, slot
,
738 struct btrfs_shared_data_ref
);
739 count
= btrfs_shared_data_ref_count(leaf
, sdref
);
740 ret
= __add_prelim_ref(prefs
, 0, NULL
, 0, key
.offset
,
744 case BTRFS_TREE_BLOCK_REF_KEY
:
745 ret
= __add_prelim_ref(prefs
, key
.offset
, NULL
,
749 case BTRFS_EXTENT_DATA_REF_KEY
: {
750 struct btrfs_extent_data_ref
*dref
;
754 dref
= btrfs_item_ptr(leaf
, slot
,
755 struct btrfs_extent_data_ref
);
756 count
= btrfs_extent_data_ref_count(leaf
, dref
);
757 key
.objectid
= btrfs_extent_data_ref_objectid(leaf
,
759 key
.type
= BTRFS_EXTENT_DATA_KEY
;
760 key
.offset
= btrfs_extent_data_ref_offset(leaf
, dref
);
761 root
= btrfs_extent_data_ref_root(leaf
, dref
);
762 ret
= __add_prelim_ref(prefs
, root
, &key
, 0, 0,
778 * this adds all existing backrefs (inline backrefs, backrefs and delayed
779 * refs) for the given bytenr to the refs list, merges duplicates and resolves
780 * indirect refs to their parent bytenr.
781 * When roots are found, they're added to the roots list
783 * FIXME some caching might speed things up
785 static int find_parent_nodes(struct btrfs_trans_handle
*trans
,
786 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
787 u64 time_seq
, struct ulist
*refs
,
788 struct ulist
*roots
, const u64
*extent_item_pos
)
790 struct btrfs_key key
;
791 struct btrfs_path
*path
;
792 struct btrfs_delayed_ref_root
*delayed_refs
= NULL
;
793 struct btrfs_delayed_ref_head
*head
;
796 struct list_head prefs_delayed
;
797 struct list_head prefs
;
798 struct __prelim_ref
*ref
;
800 INIT_LIST_HEAD(&prefs
);
801 INIT_LIST_HEAD(&prefs_delayed
);
803 key
.objectid
= bytenr
;
804 key
.offset
= (u64
)-1;
805 if (btrfs_fs_incompat(fs_info
, SKINNY_METADATA
))
806 key
.type
= BTRFS_METADATA_ITEM_KEY
;
808 key
.type
= BTRFS_EXTENT_ITEM_KEY
;
810 path
= btrfs_alloc_path();
814 path
->search_commit_root
= 1;
817 * grab both a lock on the path and a lock on the delayed ref head.
818 * We need both to get a consistent picture of how the refs look
819 * at a specified point in time
824 ret
= btrfs_search_slot(trans
, fs_info
->extent_root
, &key
, path
, 0, 0);
831 * look if there are updates for this ref queued and lock the
834 delayed_refs
= &trans
->transaction
->delayed_refs
;
835 spin_lock(&delayed_refs
->lock
);
836 head
= btrfs_find_delayed_ref_head(trans
, bytenr
);
838 if (!mutex_trylock(&head
->mutex
)) {
839 atomic_inc(&head
->node
.refs
);
840 spin_unlock(&delayed_refs
->lock
);
842 btrfs_release_path(path
);
845 * Mutex was contended, block until it's
846 * released and try again
848 mutex_lock(&head
->mutex
);
849 mutex_unlock(&head
->mutex
);
850 btrfs_put_delayed_ref(&head
->node
);
853 ret
= __add_delayed_refs(head
, time_seq
,
855 mutex_unlock(&head
->mutex
);
857 spin_unlock(&delayed_refs
->lock
);
861 spin_unlock(&delayed_refs
->lock
);
864 if (path
->slots
[0]) {
865 struct extent_buffer
*leaf
;
869 leaf
= path
->nodes
[0];
870 slot
= path
->slots
[0];
871 btrfs_item_key_to_cpu(leaf
, &key
, slot
);
872 if (key
.objectid
== bytenr
&&
873 (key
.type
== BTRFS_EXTENT_ITEM_KEY
||
874 key
.type
== BTRFS_METADATA_ITEM_KEY
)) {
875 ret
= __add_inline_refs(fs_info
, path
, bytenr
,
876 &info_level
, &prefs
);
879 ret
= __add_keyed_refs(fs_info
, path
, bytenr
,
885 btrfs_release_path(path
);
887 list_splice_init(&prefs_delayed
, &prefs
);
889 ret
= __add_missing_keys(fs_info
, &prefs
);
893 __merge_refs(&prefs
, 1);
895 ret
= __resolve_indirect_refs(fs_info
, path
, time_seq
, &prefs
,
900 __merge_refs(&prefs
, 2);
902 while (!list_empty(&prefs
)) {
903 ref
= list_first_entry(&prefs
, struct __prelim_ref
, list
);
904 list_del(&ref
->list
);
905 WARN_ON(ref
->count
< 0);
906 if (ref
->count
&& ref
->root_id
&& ref
->parent
== 0) {
907 /* no parent == root of tree */
908 ret
= ulist_add(roots
, ref
->root_id
, 0, GFP_NOFS
);
912 if (ref
->count
&& ref
->parent
) {
913 struct extent_inode_elem
*eie
= NULL
;
914 if (extent_item_pos
&& !ref
->inode_list
) {
916 struct extent_buffer
*eb
;
917 bsz
= btrfs_level_size(fs_info
->extent_root
,
919 eb
= read_tree_block(fs_info
->extent_root
,
920 ref
->parent
, bsz
, 0);
921 if (!eb
|| !extent_buffer_uptodate(eb
)) {
922 free_extent_buffer(eb
);
926 ret
= find_extent_in_eb(eb
, bytenr
,
927 *extent_item_pos
, &eie
);
928 ref
->inode_list
= eie
;
929 free_extent_buffer(eb
);
931 ret
= ulist_add_merge(refs
, ref
->parent
,
932 (uintptr_t)ref
->inode_list
,
933 (u64
*)&eie
, GFP_NOFS
);
936 if (!ret
&& extent_item_pos
) {
938 * we've recorded that parent, so we must extend
939 * its inode list here
944 eie
->next
= ref
->inode_list
;
951 btrfs_free_path(path
);
952 while (!list_empty(&prefs
)) {
953 ref
= list_first_entry(&prefs
, struct __prelim_ref
, list
);
954 list_del(&ref
->list
);
957 while (!list_empty(&prefs_delayed
)) {
958 ref
= list_first_entry(&prefs_delayed
, struct __prelim_ref
,
960 list_del(&ref
->list
);
967 static void free_leaf_list(struct ulist
*blocks
)
969 struct ulist_node
*node
= NULL
;
970 struct extent_inode_elem
*eie
;
971 struct extent_inode_elem
*eie_next
;
972 struct ulist_iterator uiter
;
974 ULIST_ITER_INIT(&uiter
);
975 while ((node
= ulist_next(blocks
, &uiter
))) {
978 eie
= (struct extent_inode_elem
*)(uintptr_t)node
->aux
;
979 for (; eie
; eie
= eie_next
) {
980 eie_next
= eie
->next
;
990 * Finds all leafs with a reference to the specified combination of bytenr and
991 * offset. key_list_head will point to a list of corresponding keys (caller must
992 * free each list element). The leafs will be stored in the leafs ulist, which
993 * must be freed with ulist_free.
995 * returns 0 on success, <0 on error
997 static int btrfs_find_all_leafs(struct btrfs_trans_handle
*trans
,
998 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
999 u64 time_seq
, struct ulist
**leafs
,
1000 const u64
*extent_item_pos
)
1005 tmp
= ulist_alloc(GFP_NOFS
);
1008 *leafs
= ulist_alloc(GFP_NOFS
);
1014 ret
= find_parent_nodes(trans
, fs_info
, bytenr
,
1015 time_seq
, *leafs
, tmp
, extent_item_pos
);
1018 if (ret
< 0 && ret
!= -ENOENT
) {
1019 free_leaf_list(*leafs
);
1027 * walk all backrefs for a given extent to find all roots that reference this
1028 * extent. Walking a backref means finding all extents that reference this
1029 * extent and in turn walk the backrefs of those, too. Naturally this is a
1030 * recursive process, but here it is implemented in an iterative fashion: We
1031 * find all referencing extents for the extent in question and put them on a
1032 * list. In turn, we find all referencing extents for those, further appending
1033 * to the list. The way we iterate the list allows adding more elements after
1034 * the current while iterating. The process stops when we reach the end of the
1035 * list. Found roots are added to the roots list.
1037 * returns 0 on success, < 0 on error.
1039 int btrfs_find_all_roots(struct btrfs_trans_handle
*trans
,
1040 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
1041 u64 time_seq
, struct ulist
**roots
)
1044 struct ulist_node
*node
= NULL
;
1045 struct ulist_iterator uiter
;
1048 tmp
= ulist_alloc(GFP_NOFS
);
1051 *roots
= ulist_alloc(GFP_NOFS
);
1057 ULIST_ITER_INIT(&uiter
);
1059 ret
= find_parent_nodes(trans
, fs_info
, bytenr
,
1060 time_seq
, tmp
, *roots
, NULL
);
1061 if (ret
< 0 && ret
!= -ENOENT
) {
1066 node
= ulist_next(tmp
, &uiter
);
1077 static int __inode_info(u64 inum
, u64 ioff
, u8 key_type
,
1078 struct btrfs_root
*fs_root
, struct btrfs_path
*path
,
1079 struct btrfs_key
*found_key
)
1082 struct btrfs_key key
;
1083 struct extent_buffer
*eb
;
1085 key
.type
= key_type
;
1086 key
.objectid
= inum
;
1089 ret
= btrfs_search_slot(NULL
, fs_root
, &key
, path
, 0, 0);
1093 eb
= path
->nodes
[0];
1094 if (ret
&& path
->slots
[0] >= btrfs_header_nritems(eb
)) {
1095 ret
= btrfs_next_leaf(fs_root
, path
);
1098 eb
= path
->nodes
[0];
1101 btrfs_item_key_to_cpu(eb
, found_key
, path
->slots
[0]);
1102 if (found_key
->type
!= key
.type
|| found_key
->objectid
!= key
.objectid
)
1109 * this makes the path point to (inum INODE_ITEM ioff)
1111 int inode_item_info(u64 inum
, u64 ioff
, struct btrfs_root
*fs_root
,
1112 struct btrfs_path
*path
)
1114 struct btrfs_key key
;
1115 return __inode_info(inum
, ioff
, BTRFS_INODE_ITEM_KEY
, fs_root
, path
,
1119 static int inode_ref_info(u64 inum
, u64 ioff
, struct btrfs_root
*fs_root
,
1120 struct btrfs_path
*path
,
1121 struct btrfs_key
*found_key
)
1123 return __inode_info(inum
, ioff
, BTRFS_INODE_REF_KEY
, fs_root
, path
,
1127 int btrfs_find_one_extref(struct btrfs_root
*root
, u64 inode_objectid
,
1128 u64 start_off
, struct btrfs_path
*path
,
1129 struct btrfs_inode_extref
**ret_extref
,
1133 struct btrfs_key key
;
1134 struct btrfs_key found_key
;
1135 struct btrfs_inode_extref
*extref
;
1136 struct extent_buffer
*leaf
;
1139 key
.objectid
= inode_objectid
;
1140 btrfs_set_key_type(&key
, BTRFS_INODE_EXTREF_KEY
);
1141 key
.offset
= start_off
;
1143 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
1148 leaf
= path
->nodes
[0];
1149 slot
= path
->slots
[0];
1150 if (slot
>= btrfs_header_nritems(leaf
)) {
1152 * If the item at offset is not found,
1153 * btrfs_search_slot will point us to the slot
1154 * where it should be inserted. In our case
1155 * that will be the slot directly before the
1156 * next INODE_REF_KEY_V2 item. In the case
1157 * that we're pointing to the last slot in a
1158 * leaf, we must move one leaf over.
1160 ret
= btrfs_next_leaf(root
, path
);
1169 btrfs_item_key_to_cpu(leaf
, &found_key
, slot
);
1172 * Check that we're still looking at an extended ref key for
1173 * this particular objectid. If we have different
1174 * objectid or type then there are no more to be found
1175 * in the tree and we can exit.
1178 if (found_key
.objectid
!= inode_objectid
)
1180 if (btrfs_key_type(&found_key
) != BTRFS_INODE_EXTREF_KEY
)
1184 ptr
= btrfs_item_ptr_offset(leaf
, path
->slots
[0]);
1185 extref
= (struct btrfs_inode_extref
*)ptr
;
1186 *ret_extref
= extref
;
1188 *found_off
= found_key
.offset
;
1196 * this iterates to turn a name (from iref/extref) into a full filesystem path.
1197 * Elements of the path are separated by '/' and the path is guaranteed to be
1198 * 0-terminated. the path is only given within the current file system.
1199 * Therefore, it never starts with a '/'. the caller is responsible to provide
1200 * "size" bytes in "dest". the dest buffer will be filled backwards. finally,
1201 * the start point of the resulting string is returned. this pointer is within
1203 * in case the path buffer would overflow, the pointer is decremented further
1204 * as if output was written to the buffer, though no more output is actually
1205 * generated. that way, the caller can determine how much space would be
1206 * required for the path to fit into the buffer. in that case, the returned
1207 * value will be smaller than dest. callers must check this!
1209 char *btrfs_ref_to_path(struct btrfs_root
*fs_root
, struct btrfs_path
*path
,
1210 u32 name_len
, unsigned long name_off
,
1211 struct extent_buffer
*eb_in
, u64 parent
,
1212 char *dest
, u32 size
)
1217 s64 bytes_left
= ((s64
)size
) - 1;
1218 struct extent_buffer
*eb
= eb_in
;
1219 struct btrfs_key found_key
;
1220 int leave_spinning
= path
->leave_spinning
;
1221 struct btrfs_inode_ref
*iref
;
1223 if (bytes_left
>= 0)
1224 dest
[bytes_left
] = '\0';
1226 path
->leave_spinning
= 1;
1228 bytes_left
-= name_len
;
1229 if (bytes_left
>= 0)
1230 read_extent_buffer(eb
, dest
+ bytes_left
,
1231 name_off
, name_len
);
1233 btrfs_tree_read_unlock_blocking(eb
);
1234 free_extent_buffer(eb
);
1236 ret
= inode_ref_info(parent
, 0, fs_root
, path
, &found_key
);
1242 next_inum
= found_key
.offset
;
1244 /* regular exit ahead */
1245 if (parent
== next_inum
)
1248 slot
= path
->slots
[0];
1249 eb
= path
->nodes
[0];
1250 /* make sure we can use eb after releasing the path */
1252 atomic_inc(&eb
->refs
);
1253 btrfs_tree_read_lock(eb
);
1254 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1256 btrfs_release_path(path
);
1257 iref
= btrfs_item_ptr(eb
, slot
, struct btrfs_inode_ref
);
1259 name_len
= btrfs_inode_ref_name_len(eb
, iref
);
1260 name_off
= (unsigned long)(iref
+ 1);
1264 if (bytes_left
>= 0)
1265 dest
[bytes_left
] = '/';
1268 btrfs_release_path(path
);
1269 path
->leave_spinning
= leave_spinning
;
1272 return ERR_PTR(ret
);
1274 return dest
+ bytes_left
;
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
,
1290 struct extent_buffer
*eb
;
1291 struct btrfs_extent_item
*ei
;
1292 struct btrfs_key key
;
1294 if (btrfs_fs_incompat(fs_info
, SKINNY_METADATA
))
1295 key
.type
= BTRFS_METADATA_ITEM_KEY
;
1297 key
.type
= BTRFS_EXTENT_ITEM_KEY
;
1298 key
.objectid
= logical
;
1299 key
.offset
= (u64
)-1;
1301 ret
= btrfs_search_slot(NULL
, fs_info
->extent_root
, &key
, path
, 0, 0);
1304 ret
= btrfs_previous_item(fs_info
->extent_root
, path
,
1305 0, BTRFS_EXTENT_ITEM_KEY
);
1309 btrfs_item_key_to_cpu(path
->nodes
[0], found_key
, path
->slots
[0]);
1310 if (found_key
->type
== BTRFS_METADATA_ITEM_KEY
)
1311 size
= fs_info
->extent_root
->leafsize
;
1312 else if (found_key
->type
== BTRFS_EXTENT_ITEM_KEY
)
1313 size
= found_key
->offset
;
1315 if ((found_key
->type
!= BTRFS_EXTENT_ITEM_KEY
&&
1316 found_key
->type
!= BTRFS_METADATA_ITEM_KEY
) ||
1317 found_key
->objectid
> logical
||
1318 found_key
->objectid
+ size
<= logical
) {
1319 pr_debug("logical %llu is not within any extent\n",
1320 (unsigned long long)logical
);
1324 eb
= path
->nodes
[0];
1325 item_size
= btrfs_item_size_nr(eb
, path
->slots
[0]);
1326 BUG_ON(item_size
< sizeof(*ei
));
1328 ei
= btrfs_item_ptr(eb
, path
->slots
[0], struct btrfs_extent_item
);
1329 flags
= btrfs_extent_flags(eb
, ei
);
1331 pr_debug("logical %llu is at position %llu within the extent (%llu "
1332 "EXTENT_ITEM %llu) flags %#llx size %u\n",
1333 (unsigned long long)logical
,
1334 (unsigned long long)(logical
- found_key
->objectid
),
1335 (unsigned long long)found_key
->objectid
,
1336 (unsigned long long)found_key
->offset
,
1337 (unsigned long long)flags
, item_size
);
1339 WARN_ON(!flags_ret
);
1341 if (flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
)
1342 *flags_ret
= BTRFS_EXTENT_FLAG_TREE_BLOCK
;
1343 else if (flags
& BTRFS_EXTENT_FLAG_DATA
)
1344 *flags_ret
= BTRFS_EXTENT_FLAG_DATA
;
1354 * helper function to iterate extent inline refs. ptr must point to a 0 value
1355 * for the first call and may be modified. it is used to track state.
1356 * if more refs exist, 0 is returned and the next call to
1357 * __get_extent_inline_ref must pass the modified ptr parameter to get the
1358 * next ref. after the last ref was processed, 1 is returned.
1359 * returns <0 on error
1361 static int __get_extent_inline_ref(unsigned long *ptr
, struct extent_buffer
*eb
,
1362 struct btrfs_extent_item
*ei
, u32 item_size
,
1363 struct btrfs_extent_inline_ref
**out_eiref
,
1368 struct btrfs_tree_block_info
*info
;
1372 flags
= btrfs_extent_flags(eb
, ei
);
1373 if (flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
) {
1374 info
= (struct btrfs_tree_block_info
*)(ei
+ 1);
1376 (struct btrfs_extent_inline_ref
*)(info
+ 1);
1378 *out_eiref
= (struct btrfs_extent_inline_ref
*)(ei
+ 1);
1380 *ptr
= (unsigned long)*out_eiref
;
1381 if ((void *)*ptr
>= (void *)ei
+ item_size
)
1385 end
= (unsigned long)ei
+ item_size
;
1386 *out_eiref
= (struct btrfs_extent_inline_ref
*)*ptr
;
1387 *out_type
= btrfs_extent_inline_ref_type(eb
, *out_eiref
);
1389 *ptr
+= btrfs_extent_inline_ref_size(*out_type
);
1390 WARN_ON(*ptr
> end
);
1392 return 1; /* last */
1398 * reads the tree block backref for an extent. tree level and root are returned
1399 * through out_level and out_root. ptr must point to a 0 value for the first
1400 * call and may be modified (see __get_extent_inline_ref comment).
1401 * returns 0 if data was provided, 1 if there was no more data to provide or
1404 int tree_backref_for_extent(unsigned long *ptr
, struct extent_buffer
*eb
,
1405 struct btrfs_extent_item
*ei
, u32 item_size
,
1406 u64
*out_root
, u8
*out_level
)
1410 struct btrfs_tree_block_info
*info
;
1411 struct btrfs_extent_inline_ref
*eiref
;
1413 if (*ptr
== (unsigned long)-1)
1417 ret
= __get_extent_inline_ref(ptr
, eb
, ei
, item_size
,
1422 if (type
== BTRFS_TREE_BLOCK_REF_KEY
||
1423 type
== BTRFS_SHARED_BLOCK_REF_KEY
)
1430 /* we can treat both ref types equally here */
1431 info
= (struct btrfs_tree_block_info
*)(ei
+ 1);
1432 *out_root
= btrfs_extent_inline_ref_offset(eb
, eiref
);
1433 *out_level
= btrfs_tree_block_level(eb
, info
);
1436 *ptr
= (unsigned long)-1;
1441 static int iterate_leaf_refs(struct extent_inode_elem
*inode_list
,
1442 u64 root
, u64 extent_item_objectid
,
1443 iterate_extent_inodes_t
*iterate
, void *ctx
)
1445 struct extent_inode_elem
*eie
;
1448 for (eie
= inode_list
; eie
; eie
= eie
->next
) {
1449 pr_debug("ref for %llu resolved, key (%llu EXTEND_DATA %llu), "
1450 "root %llu\n", extent_item_objectid
,
1451 eie
->inum
, eie
->offset
, root
);
1452 ret
= iterate(eie
->inum
, eie
->offset
, root
, ctx
);
1454 pr_debug("stopping iteration for %llu due to ret=%d\n",
1455 extent_item_objectid
, ret
);
1464 * calls iterate() for every inode that references the extent identified by
1465 * the given parameters.
1466 * when the iterator function returns a non-zero value, iteration stops.
1468 int iterate_extent_inodes(struct btrfs_fs_info
*fs_info
,
1469 u64 extent_item_objectid
, u64 extent_item_pos
,
1470 int search_commit_root
,
1471 iterate_extent_inodes_t
*iterate
, void *ctx
)
1474 struct btrfs_trans_handle
*trans
= NULL
;
1475 struct ulist
*refs
= NULL
;
1476 struct ulist
*roots
= NULL
;
1477 struct ulist_node
*ref_node
= NULL
;
1478 struct ulist_node
*root_node
= NULL
;
1479 struct seq_list tree_mod_seq_elem
= {};
1480 struct ulist_iterator ref_uiter
;
1481 struct ulist_iterator root_uiter
;
1483 pr_debug("resolving all inodes for extent %llu\n",
1484 extent_item_objectid
);
1486 if (!search_commit_root
) {
1487 trans
= btrfs_join_transaction(fs_info
->extent_root
);
1489 return PTR_ERR(trans
);
1490 btrfs_get_tree_mod_seq(fs_info
, &tree_mod_seq_elem
);
1493 ret
= btrfs_find_all_leafs(trans
, fs_info
, extent_item_objectid
,
1494 tree_mod_seq_elem
.seq
, &refs
,
1499 ULIST_ITER_INIT(&ref_uiter
);
1500 while (!ret
&& (ref_node
= ulist_next(refs
, &ref_uiter
))) {
1501 ret
= btrfs_find_all_roots(trans
, fs_info
, ref_node
->val
,
1502 tree_mod_seq_elem
.seq
, &roots
);
1505 ULIST_ITER_INIT(&root_uiter
);
1506 while (!ret
&& (root_node
= ulist_next(roots
, &root_uiter
))) {
1507 pr_debug("root %llu references leaf %llu, data list "
1508 "%#llx\n", root_node
->val
, ref_node
->val
,
1509 (long long)ref_node
->aux
);
1510 ret
= iterate_leaf_refs((struct extent_inode_elem
*)
1511 (uintptr_t)ref_node
->aux
,
1513 extent_item_objectid
,
1519 free_leaf_list(refs
);
1521 if (!search_commit_root
) {
1522 btrfs_put_tree_mod_seq(fs_info
, &tree_mod_seq_elem
);
1523 btrfs_end_transaction(trans
, fs_info
->extent_root
);
1529 int iterate_inodes_from_logical(u64 logical
, struct btrfs_fs_info
*fs_info
,
1530 struct btrfs_path
*path
,
1531 iterate_extent_inodes_t
*iterate
, void *ctx
)
1534 u64 extent_item_pos
;
1536 struct btrfs_key found_key
;
1537 int search_commit_root
= path
->search_commit_root
;
1539 ret
= extent_from_logical(fs_info
, logical
, path
, &found_key
, &flags
);
1540 btrfs_release_path(path
);
1543 if (flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
)
1546 extent_item_pos
= logical
- found_key
.objectid
;
1547 ret
= iterate_extent_inodes(fs_info
, found_key
.objectid
,
1548 extent_item_pos
, search_commit_root
,
1554 typedef int (iterate_irefs_t
)(u64 parent
, u32 name_len
, unsigned long name_off
,
1555 struct extent_buffer
*eb
, void *ctx
);
1557 static int iterate_inode_refs(u64 inum
, struct btrfs_root
*fs_root
,
1558 struct btrfs_path
*path
,
1559 iterate_irefs_t
*iterate
, void *ctx
)
1568 struct extent_buffer
*eb
;
1569 struct btrfs_item
*item
;
1570 struct btrfs_inode_ref
*iref
;
1571 struct btrfs_key found_key
;
1574 path
->leave_spinning
= 1;
1575 ret
= inode_ref_info(inum
, parent
? parent
+1 : 0, fs_root
, path
,
1580 ret
= found
? 0 : -ENOENT
;
1585 parent
= found_key
.offset
;
1586 slot
= path
->slots
[0];
1587 eb
= path
->nodes
[0];
1588 /* make sure we can use eb after releasing the path */
1589 atomic_inc(&eb
->refs
);
1590 btrfs_tree_read_lock(eb
);
1591 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1592 btrfs_release_path(path
);
1594 item
= btrfs_item_nr(eb
, slot
);
1595 iref
= btrfs_item_ptr(eb
, slot
, struct btrfs_inode_ref
);
1597 for (cur
= 0; cur
< btrfs_item_size(eb
, item
); cur
+= len
) {
1598 name_len
= btrfs_inode_ref_name_len(eb
, iref
);
1599 /* path must be released before calling iterate()! */
1600 pr_debug("following ref at offset %u for inode %llu in "
1602 (unsigned long long)found_key
.objectid
,
1603 (unsigned long long)fs_root
->objectid
);
1604 ret
= iterate(parent
, name_len
,
1605 (unsigned long)(iref
+ 1), eb
, ctx
);
1608 len
= sizeof(*iref
) + name_len
;
1609 iref
= (struct btrfs_inode_ref
*)((char *)iref
+ len
);
1611 btrfs_tree_read_unlock_blocking(eb
);
1612 free_extent_buffer(eb
);
1615 btrfs_release_path(path
);
1620 static int iterate_inode_extrefs(u64 inum
, struct btrfs_root
*fs_root
,
1621 struct btrfs_path
*path
,
1622 iterate_irefs_t
*iterate
, void *ctx
)
1629 struct extent_buffer
*eb
;
1630 struct btrfs_inode_extref
*extref
;
1631 struct extent_buffer
*leaf
;
1637 ret
= btrfs_find_one_extref(fs_root
, inum
, offset
, path
, &extref
,
1642 ret
= found
? 0 : -ENOENT
;
1647 slot
= path
->slots
[0];
1648 eb
= path
->nodes
[0];
1649 /* make sure we can use eb after releasing the path */
1650 atomic_inc(&eb
->refs
);
1652 btrfs_tree_read_lock(eb
);
1653 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1654 btrfs_release_path(path
);
1656 leaf
= path
->nodes
[0];
1657 item_size
= btrfs_item_size_nr(leaf
, path
->slots
[0]);
1658 ptr
= btrfs_item_ptr_offset(leaf
, path
->slots
[0]);
1661 while (cur_offset
< item_size
) {
1664 extref
= (struct btrfs_inode_extref
*)(ptr
+ cur_offset
);
1665 parent
= btrfs_inode_extref_parent(eb
, extref
);
1666 name_len
= btrfs_inode_extref_name_len(eb
, extref
);
1667 ret
= iterate(parent
, name_len
,
1668 (unsigned long)&extref
->name
, eb
, ctx
);
1672 cur_offset
+= btrfs_inode_extref_name_len(leaf
, extref
);
1673 cur_offset
+= sizeof(*extref
);
1675 btrfs_tree_read_unlock_blocking(eb
);
1676 free_extent_buffer(eb
);
1681 btrfs_release_path(path
);
1686 static int iterate_irefs(u64 inum
, struct btrfs_root
*fs_root
,
1687 struct btrfs_path
*path
, iterate_irefs_t
*iterate
,
1693 ret
= iterate_inode_refs(inum
, fs_root
, path
, iterate
, ctx
);
1696 else if (ret
!= -ENOENT
)
1699 ret
= iterate_inode_extrefs(inum
, fs_root
, path
, iterate
, ctx
);
1700 if (ret
== -ENOENT
&& found_refs
)
1707 * returns 0 if the path could be dumped (probably truncated)
1708 * returns <0 in case of an error
1710 static int inode_to_path(u64 inum
, u32 name_len
, unsigned long name_off
,
1711 struct extent_buffer
*eb
, void *ctx
)
1713 struct inode_fs_paths
*ipath
= ctx
;
1716 int i
= ipath
->fspath
->elem_cnt
;
1717 const int s_ptr
= sizeof(char *);
1720 bytes_left
= ipath
->fspath
->bytes_left
> s_ptr
?
1721 ipath
->fspath
->bytes_left
- s_ptr
: 0;
1723 fspath_min
= (char *)ipath
->fspath
->val
+ (i
+ 1) * s_ptr
;
1724 fspath
= btrfs_ref_to_path(ipath
->fs_root
, ipath
->btrfs_path
, name_len
,
1725 name_off
, eb
, inum
, fspath_min
, bytes_left
);
1727 return PTR_ERR(fspath
);
1729 if (fspath
> fspath_min
) {
1730 ipath
->fspath
->val
[i
] = (u64
)(unsigned long)fspath
;
1731 ++ipath
->fspath
->elem_cnt
;
1732 ipath
->fspath
->bytes_left
= fspath
- fspath_min
;
1734 ++ipath
->fspath
->elem_missed
;
1735 ipath
->fspath
->bytes_missing
+= fspath_min
- fspath
;
1736 ipath
->fspath
->bytes_left
= 0;
1743 * this dumps all file system paths to the inode into the ipath struct, provided
1744 * is has been created large enough. each path is zero-terminated and accessed
1745 * from ipath->fspath->val[i].
1746 * when it returns, there are ipath->fspath->elem_cnt number of paths available
1747 * in ipath->fspath->val[]. when the allocated space wasn't sufficient, the
1748 * number of missed paths in recored in ipath->fspath->elem_missed, otherwise,
1749 * it's zero. ipath->fspath->bytes_missing holds the number of bytes that would
1750 * have been needed to return all paths.
1752 int paths_from_inode(u64 inum
, struct inode_fs_paths
*ipath
)
1754 return iterate_irefs(inum
, ipath
->fs_root
, ipath
->btrfs_path
,
1755 inode_to_path
, ipath
);
1758 struct btrfs_data_container
*init_data_container(u32 total_bytes
)
1760 struct btrfs_data_container
*data
;
1763 alloc_bytes
= max_t(size_t, total_bytes
, sizeof(*data
));
1764 data
= vmalloc(alloc_bytes
);
1766 return ERR_PTR(-ENOMEM
);
1768 if (total_bytes
>= sizeof(*data
)) {
1769 data
->bytes_left
= total_bytes
- sizeof(*data
);
1770 data
->bytes_missing
= 0;
1772 data
->bytes_missing
= sizeof(*data
) - total_bytes
;
1773 data
->bytes_left
= 0;
1777 data
->elem_missed
= 0;
1783 * allocates space to return multiple file system paths for an inode.
1784 * total_bytes to allocate are passed, note that space usable for actual path
1785 * information will be total_bytes - sizeof(struct inode_fs_paths).
1786 * the returned pointer must be freed with free_ipath() in the end.
1788 struct inode_fs_paths
*init_ipath(s32 total_bytes
, struct btrfs_root
*fs_root
,
1789 struct btrfs_path
*path
)
1791 struct inode_fs_paths
*ifp
;
1792 struct btrfs_data_container
*fspath
;
1794 fspath
= init_data_container(total_bytes
);
1796 return (void *)fspath
;
1798 ifp
= kmalloc(sizeof(*ifp
), GFP_NOFS
);
1801 return ERR_PTR(-ENOMEM
);
1804 ifp
->btrfs_path
= path
;
1805 ifp
->fspath
= fspath
;
1806 ifp
->fs_root
= fs_root
;
1811 void free_ipath(struct inode_fs_paths
*ipath
)
1815 vfree(ipath
->fspath
);