2 * Copyright (C) 2011 STRATO. All rights reserved.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
19 #include <linux/vmalloc.h>
24 #include "transaction.h"
25 #include "delayed-ref.h"
28 struct extent_inode_elem
{
31 struct extent_inode_elem
*next
;
34 static int check_extent_in_eb(struct btrfs_key
*key
, struct extent_buffer
*eb
,
35 struct btrfs_file_extent_item
*fi
,
37 struct extent_inode_elem
**eie
)
40 struct extent_inode_elem
*e
;
42 if (!btrfs_file_extent_compression(eb
, fi
) &&
43 !btrfs_file_extent_encryption(eb
, fi
) &&
44 !btrfs_file_extent_other_encoding(eb
, fi
)) {
48 data_offset
= btrfs_file_extent_offset(eb
, fi
);
49 data_len
= btrfs_file_extent_num_bytes(eb
, fi
);
51 if (extent_item_pos
< data_offset
||
52 extent_item_pos
>= data_offset
+ data_len
)
54 offset
= extent_item_pos
- data_offset
;
57 e
= kmalloc(sizeof(*e
), GFP_NOFS
);
62 e
->inum
= key
->objectid
;
63 e
->offset
= key
->offset
+ offset
;
69 static int find_extent_in_eb(struct extent_buffer
*eb
, u64 wanted_disk_byte
,
71 struct extent_inode_elem
**eie
)
75 struct btrfs_file_extent_item
*fi
;
82 * from the shared data ref, we only have the leaf but we need
83 * the key. thus, we must look into all items and see that we
84 * find one (some) with a reference to our extent item.
86 nritems
= btrfs_header_nritems(eb
);
87 for (slot
= 0; slot
< nritems
; ++slot
) {
88 btrfs_item_key_to_cpu(eb
, &key
, slot
);
89 if (key
.type
!= BTRFS_EXTENT_DATA_KEY
)
91 fi
= btrfs_item_ptr(eb
, slot
, struct btrfs_file_extent_item
);
92 extent_type
= btrfs_file_extent_type(eb
, fi
);
93 if (extent_type
== BTRFS_FILE_EXTENT_INLINE
)
95 /* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */
96 disk_byte
= btrfs_file_extent_disk_bytenr(eb
, fi
);
97 if (disk_byte
!= wanted_disk_byte
)
100 ret
= check_extent_in_eb(&key
, eb
, fi
, extent_item_pos
, eie
);
109 * this structure records all encountered refs on the way up to the root
111 struct __prelim_ref
{
112 struct list_head list
;
114 struct btrfs_key key_for_search
;
117 struct extent_inode_elem
*inode_list
;
119 u64 wanted_disk_byte
;
123 * the rules for all callers of this function are:
124 * - obtaining the parent is the goal
125 * - if you add a key, you must know that it is a correct key
126 * - if you cannot add the parent or a correct key, then we will look into the
127 * block later to set a correct key
131 * backref type | shared | indirect | shared | indirect
132 * information | tree | tree | data | data
133 * --------------------+--------+----------+--------+----------
134 * parent logical | y | - | - | -
135 * key to resolve | - | y | y | y
136 * tree block logical | - | - | - | -
137 * root for resolving | y | y | y | y
139 * - column 1: we've the parent -> done
140 * - column 2, 3, 4: we use the key to find the parent
142 * on disk refs (inline or keyed)
143 * ==============================
144 * backref type | shared | indirect | shared | indirect
145 * information | tree | tree | data | data
146 * --------------------+--------+----------+--------+----------
147 * parent logical | y | - | y | -
148 * key to resolve | - | - | - | y
149 * tree block logical | y | y | y | y
150 * root for resolving | - | y | y | y
152 * - column 1, 3: we've the parent -> done
153 * - column 2: we take the first key from the block to find the parent
154 * (see __add_missing_keys)
155 * - column 4: we use the key to find the parent
157 * additional information that's available but not required to find the parent
158 * block might help in merging entries to gain some speed.
161 static int __add_prelim_ref(struct list_head
*head
, u64 root_id
,
162 struct btrfs_key
*key
, int level
,
163 u64 parent
, u64 wanted_disk_byte
, int count
)
165 struct __prelim_ref
*ref
;
167 /* in case we're adding delayed refs, we're holding the refs spinlock */
168 ref
= kmalloc(sizeof(*ref
), GFP_ATOMIC
);
172 ref
->root_id
= root_id
;
174 ref
->key_for_search
= *key
;
176 memset(&ref
->key_for_search
, 0, sizeof(ref
->key_for_search
));
178 ref
->inode_list
= NULL
;
181 ref
->parent
= parent
;
182 ref
->wanted_disk_byte
= wanted_disk_byte
;
183 list_add_tail(&ref
->list
, head
);
188 static int add_all_parents(struct btrfs_root
*root
, struct btrfs_path
*path
,
189 struct ulist
*parents
, int level
,
190 struct btrfs_key
*key_for_search
, u64 time_seq
,
191 u64 wanted_disk_byte
,
192 const u64
*extent_item_pos
)
196 struct extent_buffer
*eb
;
197 struct btrfs_key key
;
198 struct btrfs_file_extent_item
*fi
;
199 struct extent_inode_elem
*eie
= NULL
, *old
= NULL
;
203 eb
= path
->nodes
[level
];
204 ret
= ulist_add(parents
, eb
->start
, 0, GFP_NOFS
);
211 * We normally enter this function with the path already pointing to
212 * the first item to check. But sometimes, we may enter it with
213 * slot==nritems. In that case, go to the next leaf before we continue.
215 if (path
->slots
[0] >= btrfs_header_nritems(path
->nodes
[0]))
216 ret
= btrfs_next_old_leaf(root
, path
, time_seq
);
220 slot
= path
->slots
[0];
222 btrfs_item_key_to_cpu(eb
, &key
, slot
);
224 if (key
.objectid
!= key_for_search
->objectid
||
225 key
.type
!= BTRFS_EXTENT_DATA_KEY
)
228 fi
= btrfs_item_ptr(eb
, slot
, struct btrfs_file_extent_item
);
229 disk_byte
= btrfs_file_extent_disk_bytenr(eb
, fi
);
231 if (disk_byte
== wanted_disk_byte
) {
234 if (extent_item_pos
) {
235 ret
= check_extent_in_eb(&key
, eb
, fi
,
243 ret
= ulist_add_merge(parents
, eb
->start
,
245 (u64
*)&old
, GFP_NOFS
);
248 if (!ret
&& extent_item_pos
) {
255 ret
= btrfs_next_old_item(root
, path
, time_seq
);
264 * resolve an indirect backref in the form (root_id, key, level)
265 * to a logical address
267 static int __resolve_indirect_ref(struct btrfs_fs_info
*fs_info
,
268 struct btrfs_path
*path
, u64 time_seq
,
269 struct __prelim_ref
*ref
,
270 struct ulist
*parents
,
271 const u64
*extent_item_pos
)
273 struct btrfs_root
*root
;
274 struct btrfs_key root_key
;
275 struct extent_buffer
*eb
;
278 int level
= ref
->level
;
280 root_key
.objectid
= ref
->root_id
;
281 root_key
.type
= BTRFS_ROOT_ITEM_KEY
;
282 root_key
.offset
= (u64
)-1;
283 root
= btrfs_read_fs_root_no_name(fs_info
, &root_key
);
289 root_level
= btrfs_old_root_level(root
, time_seq
);
291 if (root_level
+ 1 == level
)
294 path
->lowest_level
= level
;
295 ret
= btrfs_search_old_slot(root
, &ref
->key_for_search
, path
, time_seq
);
296 pr_debug("search slot in root %llu (level %d, ref count %d) returned "
297 "%d for key (%llu %u %llu)\n",
298 (unsigned long long)ref
->root_id
, level
, ref
->count
, ret
,
299 (unsigned long long)ref
->key_for_search
.objectid
,
300 ref
->key_for_search
.type
,
301 (unsigned long long)ref
->key_for_search
.offset
);
305 eb
= path
->nodes
[level
];
313 eb
= path
->nodes
[level
];
316 ret
= add_all_parents(root
, path
, parents
, level
, &ref
->key_for_search
,
317 time_seq
, ref
->wanted_disk_byte
,
320 path
->lowest_level
= 0;
321 btrfs_release_path(path
);
326 * resolve all indirect backrefs from the list
328 static int __resolve_indirect_refs(struct btrfs_fs_info
*fs_info
,
329 struct btrfs_path
*path
, u64 time_seq
,
330 struct list_head
*head
,
331 const u64
*extent_item_pos
)
335 struct __prelim_ref
*ref
;
336 struct __prelim_ref
*ref_safe
;
337 struct __prelim_ref
*new_ref
;
338 struct ulist
*parents
;
339 struct ulist_node
*node
;
340 struct ulist_iterator uiter
;
342 parents
= ulist_alloc(GFP_NOFS
);
347 * _safe allows us to insert directly after the current item without
348 * iterating over the newly inserted items.
349 * we're also allowed to re-assign ref during iteration.
351 list_for_each_entry_safe(ref
, ref_safe
, head
, list
) {
352 if (ref
->parent
) /* already direct */
356 err
= __resolve_indirect_ref(fs_info
, path
, time_seq
, ref
,
357 parents
, extent_item_pos
);
363 /* we put the first parent into the ref at hand */
364 ULIST_ITER_INIT(&uiter
);
365 node
= ulist_next(parents
, &uiter
);
366 ref
->parent
= node
? node
->val
: 0;
367 ref
->inode_list
= node
?
368 (struct extent_inode_elem
*)(uintptr_t)node
->aux
: NULL
;
370 /* additional parents require new refs being added here */
371 while ((node
= ulist_next(parents
, &uiter
))) {
372 new_ref
= kmalloc(sizeof(*new_ref
), GFP_NOFS
);
377 memcpy(new_ref
, ref
, sizeof(*ref
));
378 new_ref
->parent
= node
->val
;
379 new_ref
->inode_list
= (struct extent_inode_elem
*)
380 (uintptr_t)node
->aux
;
381 list_add(&new_ref
->list
, &ref
->list
);
383 ulist_reinit(parents
);
390 static inline int ref_for_same_block(struct __prelim_ref
*ref1
,
391 struct __prelim_ref
*ref2
)
393 if (ref1
->level
!= ref2
->level
)
395 if (ref1
->root_id
!= ref2
->root_id
)
397 if (ref1
->key_for_search
.type
!= ref2
->key_for_search
.type
)
399 if (ref1
->key_for_search
.objectid
!= ref2
->key_for_search
.objectid
)
401 if (ref1
->key_for_search
.offset
!= ref2
->key_for_search
.offset
)
403 if (ref1
->parent
!= ref2
->parent
)
410 * read tree blocks and add keys where required.
412 static int __add_missing_keys(struct btrfs_fs_info
*fs_info
,
413 struct list_head
*head
)
415 struct list_head
*pos
;
416 struct extent_buffer
*eb
;
418 list_for_each(pos
, head
) {
419 struct __prelim_ref
*ref
;
420 ref
= list_entry(pos
, struct __prelim_ref
, list
);
424 if (ref
->key_for_search
.type
)
426 BUG_ON(!ref
->wanted_disk_byte
);
427 eb
= read_tree_block(fs_info
->tree_root
, ref
->wanted_disk_byte
,
428 fs_info
->tree_root
->leafsize
, 0);
429 if (!eb
|| !extent_buffer_uptodate(eb
)) {
430 free_extent_buffer(eb
);
433 btrfs_tree_read_lock(eb
);
434 if (btrfs_header_level(eb
) == 0)
435 btrfs_item_key_to_cpu(eb
, &ref
->key_for_search
, 0);
437 btrfs_node_key_to_cpu(eb
, &ref
->key_for_search
, 0);
438 btrfs_tree_read_unlock(eb
);
439 free_extent_buffer(eb
);
445 * merge two lists of backrefs and adjust counts accordingly
447 * mode = 1: merge identical keys, if key is set
448 * FIXME: if we add more keys in __add_prelim_ref, we can merge more here.
449 * additionally, we could even add a key range for the blocks we
450 * looked into to merge even more (-> replace unresolved refs by those
452 * mode = 2: merge identical parents
454 static void __merge_refs(struct list_head
*head
, int mode
)
456 struct list_head
*pos1
;
458 list_for_each(pos1
, head
) {
459 struct list_head
*n2
;
460 struct list_head
*pos2
;
461 struct __prelim_ref
*ref1
;
463 ref1
= list_entry(pos1
, struct __prelim_ref
, list
);
465 for (pos2
= pos1
->next
, n2
= pos2
->next
; pos2
!= head
;
466 pos2
= n2
, n2
= pos2
->next
) {
467 struct __prelim_ref
*ref2
;
468 struct __prelim_ref
*xchg
;
469 struct extent_inode_elem
*eie
;
471 ref2
= list_entry(pos2
, struct __prelim_ref
, list
);
474 if (!ref_for_same_block(ref1
, ref2
))
476 if (!ref1
->parent
&& ref2
->parent
) {
482 if (ref1
->parent
!= ref2
->parent
)
486 eie
= ref1
->inode_list
;
487 while (eie
&& eie
->next
)
490 eie
->next
= ref2
->inode_list
;
492 ref1
->inode_list
= ref2
->inode_list
;
493 ref1
->count
+= ref2
->count
;
495 list_del(&ref2
->list
);
503 * add all currently queued delayed refs from this head whose seq nr is
504 * smaller or equal that seq to the list
506 static int __add_delayed_refs(struct btrfs_delayed_ref_head
*head
, u64 seq
,
507 struct list_head
*prefs
)
509 struct btrfs_delayed_extent_op
*extent_op
= head
->extent_op
;
510 struct rb_node
*n
= &head
->node
.rb_node
;
511 struct btrfs_key key
;
512 struct btrfs_key op_key
= {0};
516 if (extent_op
&& extent_op
->update_key
)
517 btrfs_disk_key_to_cpu(&op_key
, &extent_op
->key
);
519 while ((n
= rb_prev(n
))) {
520 struct btrfs_delayed_ref_node
*node
;
521 node
= rb_entry(n
, struct btrfs_delayed_ref_node
,
523 if (node
->bytenr
!= head
->node
.bytenr
)
525 WARN_ON(node
->is_head
);
530 switch (node
->action
) {
531 case BTRFS_ADD_DELAYED_EXTENT
:
532 case BTRFS_UPDATE_DELAYED_HEAD
:
535 case BTRFS_ADD_DELAYED_REF
:
538 case BTRFS_DROP_DELAYED_REF
:
544 switch (node
->type
) {
545 case BTRFS_TREE_BLOCK_REF_KEY
: {
546 struct btrfs_delayed_tree_ref
*ref
;
548 ref
= btrfs_delayed_node_to_tree_ref(node
);
549 ret
= __add_prelim_ref(prefs
, ref
->root
, &op_key
,
550 ref
->level
+ 1, 0, node
->bytenr
,
551 node
->ref_mod
* sgn
);
554 case BTRFS_SHARED_BLOCK_REF_KEY
: {
555 struct btrfs_delayed_tree_ref
*ref
;
557 ref
= btrfs_delayed_node_to_tree_ref(node
);
558 ret
= __add_prelim_ref(prefs
, ref
->root
, NULL
,
559 ref
->level
+ 1, ref
->parent
,
561 node
->ref_mod
* sgn
);
564 case BTRFS_EXTENT_DATA_REF_KEY
: {
565 struct btrfs_delayed_data_ref
*ref
;
566 ref
= btrfs_delayed_node_to_data_ref(node
);
568 key
.objectid
= ref
->objectid
;
569 key
.type
= BTRFS_EXTENT_DATA_KEY
;
570 key
.offset
= ref
->offset
;
571 ret
= __add_prelim_ref(prefs
, ref
->root
, &key
, 0, 0,
573 node
->ref_mod
* sgn
);
576 case BTRFS_SHARED_DATA_REF_KEY
: {
577 struct btrfs_delayed_data_ref
*ref
;
579 ref
= btrfs_delayed_node_to_data_ref(node
);
581 key
.objectid
= ref
->objectid
;
582 key
.type
= BTRFS_EXTENT_DATA_KEY
;
583 key
.offset
= ref
->offset
;
584 ret
= __add_prelim_ref(prefs
, ref
->root
, &key
, 0,
585 ref
->parent
, node
->bytenr
,
586 node
->ref_mod
* sgn
);
600 * add all inline backrefs for bytenr to the list
602 static int __add_inline_refs(struct btrfs_fs_info
*fs_info
,
603 struct btrfs_path
*path
, u64 bytenr
,
604 int *info_level
, struct list_head
*prefs
)
608 struct extent_buffer
*leaf
;
609 struct btrfs_key key
;
610 struct btrfs_key found_key
;
613 struct btrfs_extent_item
*ei
;
618 * enumerate all inline refs
620 leaf
= path
->nodes
[0];
621 slot
= path
->slots
[0];
623 item_size
= btrfs_item_size_nr(leaf
, slot
);
624 BUG_ON(item_size
< sizeof(*ei
));
626 ei
= btrfs_item_ptr(leaf
, slot
, struct btrfs_extent_item
);
627 flags
= btrfs_extent_flags(leaf
, ei
);
628 btrfs_item_key_to_cpu(leaf
, &found_key
, slot
);
630 ptr
= (unsigned long)(ei
+ 1);
631 end
= (unsigned long)ei
+ item_size
;
633 if (found_key
.type
== BTRFS_EXTENT_ITEM_KEY
&&
634 flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
) {
635 struct btrfs_tree_block_info
*info
;
637 info
= (struct btrfs_tree_block_info
*)ptr
;
638 *info_level
= btrfs_tree_block_level(leaf
, info
);
639 ptr
+= sizeof(struct btrfs_tree_block_info
);
641 } else if (found_key
.type
== BTRFS_METADATA_ITEM_KEY
) {
642 *info_level
= found_key
.offset
;
644 BUG_ON(!(flags
& BTRFS_EXTENT_FLAG_DATA
));
648 struct btrfs_extent_inline_ref
*iref
;
652 iref
= (struct btrfs_extent_inline_ref
*)ptr
;
653 type
= btrfs_extent_inline_ref_type(leaf
, iref
);
654 offset
= btrfs_extent_inline_ref_offset(leaf
, iref
);
657 case BTRFS_SHARED_BLOCK_REF_KEY
:
658 ret
= __add_prelim_ref(prefs
, 0, NULL
,
659 *info_level
+ 1, offset
,
662 case BTRFS_SHARED_DATA_REF_KEY
: {
663 struct btrfs_shared_data_ref
*sdref
;
666 sdref
= (struct btrfs_shared_data_ref
*)(iref
+ 1);
667 count
= btrfs_shared_data_ref_count(leaf
, sdref
);
668 ret
= __add_prelim_ref(prefs
, 0, NULL
, 0, offset
,
672 case BTRFS_TREE_BLOCK_REF_KEY
:
673 ret
= __add_prelim_ref(prefs
, offset
, NULL
,
677 case BTRFS_EXTENT_DATA_REF_KEY
: {
678 struct btrfs_extent_data_ref
*dref
;
682 dref
= (struct btrfs_extent_data_ref
*)(&iref
->offset
);
683 count
= btrfs_extent_data_ref_count(leaf
, dref
);
684 key
.objectid
= btrfs_extent_data_ref_objectid(leaf
,
686 key
.type
= BTRFS_EXTENT_DATA_KEY
;
687 key
.offset
= btrfs_extent_data_ref_offset(leaf
, dref
);
688 root
= btrfs_extent_data_ref_root(leaf
, dref
);
689 ret
= __add_prelim_ref(prefs
, root
, &key
, 0, 0,
698 ptr
+= btrfs_extent_inline_ref_size(type
);
705 * add all non-inline backrefs for bytenr to the list
707 static int __add_keyed_refs(struct btrfs_fs_info
*fs_info
,
708 struct btrfs_path
*path
, u64 bytenr
,
709 int info_level
, struct list_head
*prefs
)
711 struct btrfs_root
*extent_root
= fs_info
->extent_root
;
714 struct extent_buffer
*leaf
;
715 struct btrfs_key key
;
718 ret
= btrfs_next_item(extent_root
, path
);
726 slot
= path
->slots
[0];
727 leaf
= path
->nodes
[0];
728 btrfs_item_key_to_cpu(leaf
, &key
, slot
);
730 if (key
.objectid
!= bytenr
)
732 if (key
.type
< BTRFS_TREE_BLOCK_REF_KEY
)
734 if (key
.type
> BTRFS_SHARED_DATA_REF_KEY
)
738 case BTRFS_SHARED_BLOCK_REF_KEY
:
739 ret
= __add_prelim_ref(prefs
, 0, NULL
,
740 info_level
+ 1, key
.offset
,
743 case BTRFS_SHARED_DATA_REF_KEY
: {
744 struct btrfs_shared_data_ref
*sdref
;
747 sdref
= btrfs_item_ptr(leaf
, slot
,
748 struct btrfs_shared_data_ref
);
749 count
= btrfs_shared_data_ref_count(leaf
, sdref
);
750 ret
= __add_prelim_ref(prefs
, 0, NULL
, 0, key
.offset
,
754 case BTRFS_TREE_BLOCK_REF_KEY
:
755 ret
= __add_prelim_ref(prefs
, key
.offset
, NULL
,
759 case BTRFS_EXTENT_DATA_REF_KEY
: {
760 struct btrfs_extent_data_ref
*dref
;
764 dref
= btrfs_item_ptr(leaf
, slot
,
765 struct btrfs_extent_data_ref
);
766 count
= btrfs_extent_data_ref_count(leaf
, dref
);
767 key
.objectid
= btrfs_extent_data_ref_objectid(leaf
,
769 key
.type
= BTRFS_EXTENT_DATA_KEY
;
770 key
.offset
= btrfs_extent_data_ref_offset(leaf
, dref
);
771 root
= btrfs_extent_data_ref_root(leaf
, dref
);
772 ret
= __add_prelim_ref(prefs
, root
, &key
, 0, 0,
788 * this adds all existing backrefs (inline backrefs, backrefs and delayed
789 * refs) for the given bytenr to the refs list, merges duplicates and resolves
790 * indirect refs to their parent bytenr.
791 * When roots are found, they're added to the roots list
793 * FIXME some caching might speed things up
795 static int find_parent_nodes(struct btrfs_trans_handle
*trans
,
796 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
797 u64 time_seq
, struct ulist
*refs
,
798 struct ulist
*roots
, const u64
*extent_item_pos
)
800 struct btrfs_key key
;
801 struct btrfs_path
*path
;
802 struct btrfs_delayed_ref_root
*delayed_refs
= NULL
;
803 struct btrfs_delayed_ref_head
*head
;
806 struct list_head prefs_delayed
;
807 struct list_head prefs
;
808 struct __prelim_ref
*ref
;
810 INIT_LIST_HEAD(&prefs
);
811 INIT_LIST_HEAD(&prefs_delayed
);
813 key
.objectid
= bytenr
;
814 key
.offset
= (u64
)-1;
815 if (btrfs_fs_incompat(fs_info
, SKINNY_METADATA
))
816 key
.type
= BTRFS_METADATA_ITEM_KEY
;
818 key
.type
= BTRFS_EXTENT_ITEM_KEY
;
820 path
= btrfs_alloc_path();
824 path
->search_commit_root
= 1;
827 * grab both a lock on the path and a lock on the delayed ref head.
828 * We need both to get a consistent picture of how the refs look
829 * at a specified point in time
834 ret
= btrfs_search_slot(trans
, fs_info
->extent_root
, &key
, path
, 0, 0);
841 * look if there are updates for this ref queued and lock the
844 delayed_refs
= &trans
->transaction
->delayed_refs
;
845 spin_lock(&delayed_refs
->lock
);
846 head
= btrfs_find_delayed_ref_head(trans
, bytenr
);
848 if (!mutex_trylock(&head
->mutex
)) {
849 atomic_inc(&head
->node
.refs
);
850 spin_unlock(&delayed_refs
->lock
);
852 btrfs_release_path(path
);
855 * Mutex was contended, block until it's
856 * released and try again
858 mutex_lock(&head
->mutex
);
859 mutex_unlock(&head
->mutex
);
860 btrfs_put_delayed_ref(&head
->node
);
863 ret
= __add_delayed_refs(head
, time_seq
,
865 mutex_unlock(&head
->mutex
);
867 spin_unlock(&delayed_refs
->lock
);
871 spin_unlock(&delayed_refs
->lock
);
874 if (path
->slots
[0]) {
875 struct extent_buffer
*leaf
;
879 leaf
= path
->nodes
[0];
880 slot
= path
->slots
[0];
881 btrfs_item_key_to_cpu(leaf
, &key
, slot
);
882 if (key
.objectid
== bytenr
&&
883 (key
.type
== BTRFS_EXTENT_ITEM_KEY
||
884 key
.type
== BTRFS_METADATA_ITEM_KEY
)) {
885 ret
= __add_inline_refs(fs_info
, path
, bytenr
,
886 &info_level
, &prefs
);
889 ret
= __add_keyed_refs(fs_info
, path
, bytenr
,
895 btrfs_release_path(path
);
897 list_splice_init(&prefs_delayed
, &prefs
);
899 ret
= __add_missing_keys(fs_info
, &prefs
);
903 __merge_refs(&prefs
, 1);
905 ret
= __resolve_indirect_refs(fs_info
, path
, time_seq
, &prefs
,
910 __merge_refs(&prefs
, 2);
912 while (!list_empty(&prefs
)) {
913 ref
= list_first_entry(&prefs
, struct __prelim_ref
, list
);
914 WARN_ON(ref
->count
< 0);
915 if (ref
->count
&& ref
->root_id
&& ref
->parent
== 0) {
916 /* no parent == root of tree */
917 ret
= ulist_add(roots
, ref
->root_id
, 0, GFP_NOFS
);
921 if (ref
->count
&& ref
->parent
) {
922 struct extent_inode_elem
*eie
= NULL
;
923 if (extent_item_pos
&& !ref
->inode_list
) {
925 struct extent_buffer
*eb
;
926 bsz
= btrfs_level_size(fs_info
->extent_root
,
928 eb
= read_tree_block(fs_info
->extent_root
,
929 ref
->parent
, bsz
, 0);
930 if (!eb
|| !extent_buffer_uptodate(eb
)) {
931 free_extent_buffer(eb
);
935 ret
= find_extent_in_eb(eb
, bytenr
,
936 *extent_item_pos
, &eie
);
937 free_extent_buffer(eb
);
940 ref
->inode_list
= eie
;
942 ret
= ulist_add_merge(refs
, ref
->parent
,
943 (uintptr_t)ref
->inode_list
,
944 (u64
*)&eie
, GFP_NOFS
);
947 if (!ret
&& extent_item_pos
) {
949 * we've recorded that parent, so we must extend
950 * its inode list here
955 eie
->next
= ref
->inode_list
;
958 list_del(&ref
->list
);
963 btrfs_free_path(path
);
964 while (!list_empty(&prefs
)) {
965 ref
= list_first_entry(&prefs
, struct __prelim_ref
, list
);
966 list_del(&ref
->list
);
969 while (!list_empty(&prefs_delayed
)) {
970 ref
= list_first_entry(&prefs_delayed
, struct __prelim_ref
,
972 list_del(&ref
->list
);
979 static void free_leaf_list(struct ulist
*blocks
)
981 struct ulist_node
*node
= NULL
;
982 struct extent_inode_elem
*eie
;
983 struct extent_inode_elem
*eie_next
;
984 struct ulist_iterator uiter
;
986 ULIST_ITER_INIT(&uiter
);
987 while ((node
= ulist_next(blocks
, &uiter
))) {
990 eie
= (struct extent_inode_elem
*)(uintptr_t)node
->aux
;
991 for (; eie
; eie
= eie_next
) {
992 eie_next
= eie
->next
;
1002 * Finds all leafs with a reference to the specified combination of bytenr and
1003 * offset. key_list_head will point to a list of corresponding keys (caller must
1004 * free each list element). The leafs will be stored in the leafs ulist, which
1005 * must be freed with ulist_free.
1007 * returns 0 on success, <0 on error
1009 static int btrfs_find_all_leafs(struct btrfs_trans_handle
*trans
,
1010 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
1011 u64 time_seq
, struct ulist
**leafs
,
1012 const u64
*extent_item_pos
)
1017 tmp
= ulist_alloc(GFP_NOFS
);
1020 *leafs
= ulist_alloc(GFP_NOFS
);
1026 ret
= find_parent_nodes(trans
, fs_info
, bytenr
,
1027 time_seq
, *leafs
, tmp
, extent_item_pos
);
1030 if (ret
< 0 && ret
!= -ENOENT
) {
1031 free_leaf_list(*leafs
);
1039 * walk all backrefs for a given extent to find all roots that reference this
1040 * extent. Walking a backref means finding all extents that reference this
1041 * extent and in turn walk the backrefs of those, too. Naturally this is a
1042 * recursive process, but here it is implemented in an iterative fashion: We
1043 * find all referencing extents for the extent in question and put them on a
1044 * list. In turn, we find all referencing extents for those, further appending
1045 * to the list. The way we iterate the list allows adding more elements after
1046 * the current while iterating. The process stops when we reach the end of the
1047 * list. Found roots are added to the roots list.
1049 * returns 0 on success, < 0 on error.
1051 int btrfs_find_all_roots(struct btrfs_trans_handle
*trans
,
1052 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
1053 u64 time_seq
, struct ulist
**roots
)
1056 struct ulist_node
*node
= NULL
;
1057 struct ulist_iterator uiter
;
1060 tmp
= ulist_alloc(GFP_NOFS
);
1063 *roots
= ulist_alloc(GFP_NOFS
);
1069 ULIST_ITER_INIT(&uiter
);
1071 ret
= find_parent_nodes(trans
, fs_info
, bytenr
,
1072 time_seq
, tmp
, *roots
, NULL
);
1073 if (ret
< 0 && ret
!= -ENOENT
) {
1078 node
= ulist_next(tmp
, &uiter
);
1089 static int __inode_info(u64 inum
, u64 ioff
, u8 key_type
,
1090 struct btrfs_root
*fs_root
, struct btrfs_path
*path
,
1091 struct btrfs_key
*found_key
)
1094 struct btrfs_key key
;
1095 struct extent_buffer
*eb
;
1097 key
.type
= key_type
;
1098 key
.objectid
= inum
;
1101 ret
= btrfs_search_slot(NULL
, fs_root
, &key
, path
, 0, 0);
1105 eb
= path
->nodes
[0];
1106 if (ret
&& path
->slots
[0] >= btrfs_header_nritems(eb
)) {
1107 ret
= btrfs_next_leaf(fs_root
, path
);
1110 eb
= path
->nodes
[0];
1113 btrfs_item_key_to_cpu(eb
, found_key
, path
->slots
[0]);
1114 if (found_key
->type
!= key
.type
|| found_key
->objectid
!= key
.objectid
)
1121 * this makes the path point to (inum INODE_ITEM ioff)
1123 int inode_item_info(u64 inum
, u64 ioff
, struct btrfs_root
*fs_root
,
1124 struct btrfs_path
*path
)
1126 struct btrfs_key key
;
1127 return __inode_info(inum
, ioff
, BTRFS_INODE_ITEM_KEY
, fs_root
, path
,
1131 static int inode_ref_info(u64 inum
, u64 ioff
, struct btrfs_root
*fs_root
,
1132 struct btrfs_path
*path
,
1133 struct btrfs_key
*found_key
)
1135 return __inode_info(inum
, ioff
, BTRFS_INODE_REF_KEY
, fs_root
, path
,
1139 int btrfs_find_one_extref(struct btrfs_root
*root
, u64 inode_objectid
,
1140 u64 start_off
, struct btrfs_path
*path
,
1141 struct btrfs_inode_extref
**ret_extref
,
1145 struct btrfs_key key
;
1146 struct btrfs_key found_key
;
1147 struct btrfs_inode_extref
*extref
;
1148 struct extent_buffer
*leaf
;
1151 key
.objectid
= inode_objectid
;
1152 btrfs_set_key_type(&key
, BTRFS_INODE_EXTREF_KEY
);
1153 key
.offset
= start_off
;
1155 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
1160 leaf
= path
->nodes
[0];
1161 slot
= path
->slots
[0];
1162 if (slot
>= btrfs_header_nritems(leaf
)) {
1164 * If the item at offset is not found,
1165 * btrfs_search_slot will point us to the slot
1166 * where it should be inserted. In our case
1167 * that will be the slot directly before the
1168 * next INODE_REF_KEY_V2 item. In the case
1169 * that we're pointing to the last slot in a
1170 * leaf, we must move one leaf over.
1172 ret
= btrfs_next_leaf(root
, path
);
1181 btrfs_item_key_to_cpu(leaf
, &found_key
, slot
);
1184 * Check that we're still looking at an extended ref key for
1185 * this particular objectid. If we have different
1186 * objectid or type then there are no more to be found
1187 * in the tree and we can exit.
1190 if (found_key
.objectid
!= inode_objectid
)
1192 if (btrfs_key_type(&found_key
) != BTRFS_INODE_EXTREF_KEY
)
1196 ptr
= btrfs_item_ptr_offset(leaf
, path
->slots
[0]);
1197 extref
= (struct btrfs_inode_extref
*)ptr
;
1198 *ret_extref
= extref
;
1200 *found_off
= found_key
.offset
;
1208 * this iterates to turn a name (from iref/extref) into a full filesystem path.
1209 * Elements of the path are separated by '/' and the path is guaranteed to be
1210 * 0-terminated. the path is only given within the current file system.
1211 * Therefore, it never starts with a '/'. the caller is responsible to provide
1212 * "size" bytes in "dest". the dest buffer will be filled backwards. finally,
1213 * the start point of the resulting string is returned. this pointer is within
1215 * in case the path buffer would overflow, the pointer is decremented further
1216 * as if output was written to the buffer, though no more output is actually
1217 * generated. that way, the caller can determine how much space would be
1218 * required for the path to fit into the buffer. in that case, the returned
1219 * value will be smaller than dest. callers must check this!
1221 char *btrfs_ref_to_path(struct btrfs_root
*fs_root
, struct btrfs_path
*path
,
1222 u32 name_len
, unsigned long name_off
,
1223 struct extent_buffer
*eb_in
, u64 parent
,
1224 char *dest
, u32 size
)
1229 s64 bytes_left
= ((s64
)size
) - 1;
1230 struct extent_buffer
*eb
= eb_in
;
1231 struct btrfs_key found_key
;
1232 int leave_spinning
= path
->leave_spinning
;
1233 struct btrfs_inode_ref
*iref
;
1235 if (bytes_left
>= 0)
1236 dest
[bytes_left
] = '\0';
1238 path
->leave_spinning
= 1;
1240 bytes_left
-= name_len
;
1241 if (bytes_left
>= 0)
1242 read_extent_buffer(eb
, dest
+ bytes_left
,
1243 name_off
, name_len
);
1245 btrfs_tree_read_unlock_blocking(eb
);
1246 free_extent_buffer(eb
);
1248 ret
= inode_ref_info(parent
, 0, fs_root
, path
, &found_key
);
1254 next_inum
= found_key
.offset
;
1256 /* regular exit ahead */
1257 if (parent
== next_inum
)
1260 slot
= path
->slots
[0];
1261 eb
= path
->nodes
[0];
1262 /* make sure we can use eb after releasing the path */
1264 atomic_inc(&eb
->refs
);
1265 btrfs_tree_read_lock(eb
);
1266 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1268 btrfs_release_path(path
);
1269 iref
= btrfs_item_ptr(eb
, slot
, struct btrfs_inode_ref
);
1271 name_len
= btrfs_inode_ref_name_len(eb
, iref
);
1272 name_off
= (unsigned long)(iref
+ 1);
1276 if (bytes_left
>= 0)
1277 dest
[bytes_left
] = '/';
1280 btrfs_release_path(path
);
1281 path
->leave_spinning
= leave_spinning
;
1284 return ERR_PTR(ret
);
1286 return dest
+ bytes_left
;
1290 * this makes the path point to (logical EXTENT_ITEM *)
1291 * returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for
1292 * tree blocks and <0 on error.
1294 int extent_from_logical(struct btrfs_fs_info
*fs_info
, u64 logical
,
1295 struct btrfs_path
*path
, struct btrfs_key
*found_key
,
1302 struct extent_buffer
*eb
;
1303 struct btrfs_extent_item
*ei
;
1304 struct btrfs_key key
;
1306 if (btrfs_fs_incompat(fs_info
, SKINNY_METADATA
))
1307 key
.type
= BTRFS_METADATA_ITEM_KEY
;
1309 key
.type
= BTRFS_EXTENT_ITEM_KEY
;
1310 key
.objectid
= logical
;
1311 key
.offset
= (u64
)-1;
1313 ret
= btrfs_search_slot(NULL
, fs_info
->extent_root
, &key
, path
, 0, 0);
1316 ret
= btrfs_previous_item(fs_info
->extent_root
, path
,
1317 0, BTRFS_EXTENT_ITEM_KEY
);
1321 btrfs_item_key_to_cpu(path
->nodes
[0], found_key
, path
->slots
[0]);
1322 if (found_key
->type
== BTRFS_METADATA_ITEM_KEY
)
1323 size
= fs_info
->extent_root
->leafsize
;
1324 else if (found_key
->type
== BTRFS_EXTENT_ITEM_KEY
)
1325 size
= found_key
->offset
;
1327 if ((found_key
->type
!= BTRFS_EXTENT_ITEM_KEY
&&
1328 found_key
->type
!= BTRFS_METADATA_ITEM_KEY
) ||
1329 found_key
->objectid
> logical
||
1330 found_key
->objectid
+ size
<= logical
) {
1331 pr_debug("logical %llu is not within any extent\n",
1332 (unsigned long long)logical
);
1336 eb
= path
->nodes
[0];
1337 item_size
= btrfs_item_size_nr(eb
, path
->slots
[0]);
1338 BUG_ON(item_size
< sizeof(*ei
));
1340 ei
= btrfs_item_ptr(eb
, path
->slots
[0], struct btrfs_extent_item
);
1341 flags
= btrfs_extent_flags(eb
, ei
);
1343 pr_debug("logical %llu is at position %llu within the extent (%llu "
1344 "EXTENT_ITEM %llu) flags %#llx size %u\n",
1345 (unsigned long long)logical
,
1346 (unsigned long long)(logical
- found_key
->objectid
),
1347 (unsigned long long)found_key
->objectid
,
1348 (unsigned long long)found_key
->offset
,
1349 (unsigned long long)flags
, item_size
);
1351 WARN_ON(!flags_ret
);
1353 if (flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
)
1354 *flags_ret
= BTRFS_EXTENT_FLAG_TREE_BLOCK
;
1355 else if (flags
& BTRFS_EXTENT_FLAG_DATA
)
1356 *flags_ret
= BTRFS_EXTENT_FLAG_DATA
;
1366 * helper function to iterate extent inline refs. ptr must point to a 0 value
1367 * for the first call and may be modified. it is used to track state.
1368 * if more refs exist, 0 is returned and the next call to
1369 * __get_extent_inline_ref must pass the modified ptr parameter to get the
1370 * next ref. after the last ref was processed, 1 is returned.
1371 * returns <0 on error
1373 static int __get_extent_inline_ref(unsigned long *ptr
, struct extent_buffer
*eb
,
1374 struct btrfs_extent_item
*ei
, u32 item_size
,
1375 struct btrfs_extent_inline_ref
**out_eiref
,
1380 struct btrfs_tree_block_info
*info
;
1384 flags
= btrfs_extent_flags(eb
, ei
);
1385 if (flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
) {
1386 info
= (struct btrfs_tree_block_info
*)(ei
+ 1);
1388 (struct btrfs_extent_inline_ref
*)(info
+ 1);
1390 *out_eiref
= (struct btrfs_extent_inline_ref
*)(ei
+ 1);
1392 *ptr
= (unsigned long)*out_eiref
;
1393 if ((void *)*ptr
>= (void *)ei
+ item_size
)
1397 end
= (unsigned long)ei
+ item_size
;
1398 *out_eiref
= (struct btrfs_extent_inline_ref
*)*ptr
;
1399 *out_type
= btrfs_extent_inline_ref_type(eb
, *out_eiref
);
1401 *ptr
+= btrfs_extent_inline_ref_size(*out_type
);
1402 WARN_ON(*ptr
> end
);
1404 return 1; /* last */
1410 * reads the tree block backref for an extent. tree level and root are returned
1411 * through out_level and out_root. ptr must point to a 0 value for the first
1412 * call and may be modified (see __get_extent_inline_ref comment).
1413 * returns 0 if data was provided, 1 if there was no more data to provide or
1416 int tree_backref_for_extent(unsigned long *ptr
, struct extent_buffer
*eb
,
1417 struct btrfs_extent_item
*ei
, u32 item_size
,
1418 u64
*out_root
, u8
*out_level
)
1422 struct btrfs_tree_block_info
*info
;
1423 struct btrfs_extent_inline_ref
*eiref
;
1425 if (*ptr
== (unsigned long)-1)
1429 ret
= __get_extent_inline_ref(ptr
, eb
, ei
, item_size
,
1434 if (type
== BTRFS_TREE_BLOCK_REF_KEY
||
1435 type
== BTRFS_SHARED_BLOCK_REF_KEY
)
1442 /* we can treat both ref types equally here */
1443 info
= (struct btrfs_tree_block_info
*)(ei
+ 1);
1444 *out_root
= btrfs_extent_inline_ref_offset(eb
, eiref
);
1445 *out_level
= btrfs_tree_block_level(eb
, info
);
1448 *ptr
= (unsigned long)-1;
1453 static int iterate_leaf_refs(struct extent_inode_elem
*inode_list
,
1454 u64 root
, u64 extent_item_objectid
,
1455 iterate_extent_inodes_t
*iterate
, void *ctx
)
1457 struct extent_inode_elem
*eie
;
1460 for (eie
= inode_list
; eie
; eie
= eie
->next
) {
1461 pr_debug("ref for %llu resolved, key (%llu EXTEND_DATA %llu), "
1462 "root %llu\n", extent_item_objectid
,
1463 eie
->inum
, eie
->offset
, root
);
1464 ret
= iterate(eie
->inum
, eie
->offset
, root
, ctx
);
1466 pr_debug("stopping iteration for %llu due to ret=%d\n",
1467 extent_item_objectid
, ret
);
1476 * calls iterate() for every inode that references the extent identified by
1477 * the given parameters.
1478 * when the iterator function returns a non-zero value, iteration stops.
1480 int iterate_extent_inodes(struct btrfs_fs_info
*fs_info
,
1481 u64 extent_item_objectid
, u64 extent_item_pos
,
1482 int search_commit_root
,
1483 iterate_extent_inodes_t
*iterate
, void *ctx
)
1486 struct btrfs_trans_handle
*trans
= NULL
;
1487 struct ulist
*refs
= NULL
;
1488 struct ulist
*roots
= NULL
;
1489 struct ulist_node
*ref_node
= NULL
;
1490 struct ulist_node
*root_node
= NULL
;
1491 struct seq_list tree_mod_seq_elem
= {};
1492 struct ulist_iterator ref_uiter
;
1493 struct ulist_iterator root_uiter
;
1495 pr_debug("resolving all inodes for extent %llu\n",
1496 extent_item_objectid
);
1498 if (!search_commit_root
) {
1499 trans
= btrfs_join_transaction(fs_info
->extent_root
);
1501 return PTR_ERR(trans
);
1502 btrfs_get_tree_mod_seq(fs_info
, &tree_mod_seq_elem
);
1505 ret
= btrfs_find_all_leafs(trans
, fs_info
, extent_item_objectid
,
1506 tree_mod_seq_elem
.seq
, &refs
,
1511 ULIST_ITER_INIT(&ref_uiter
);
1512 while (!ret
&& (ref_node
= ulist_next(refs
, &ref_uiter
))) {
1513 ret
= btrfs_find_all_roots(trans
, fs_info
, ref_node
->val
,
1514 tree_mod_seq_elem
.seq
, &roots
);
1517 ULIST_ITER_INIT(&root_uiter
);
1518 while (!ret
&& (root_node
= ulist_next(roots
, &root_uiter
))) {
1519 pr_debug("root %llu references leaf %llu, data list "
1520 "%#llx\n", root_node
->val
, ref_node
->val
,
1521 (long long)ref_node
->aux
);
1522 ret
= iterate_leaf_refs((struct extent_inode_elem
*)
1523 (uintptr_t)ref_node
->aux
,
1525 extent_item_objectid
,
1531 free_leaf_list(refs
);
1533 if (!search_commit_root
) {
1534 btrfs_put_tree_mod_seq(fs_info
, &tree_mod_seq_elem
);
1535 btrfs_end_transaction(trans
, fs_info
->extent_root
);
1541 int iterate_inodes_from_logical(u64 logical
, struct btrfs_fs_info
*fs_info
,
1542 struct btrfs_path
*path
,
1543 iterate_extent_inodes_t
*iterate
, void *ctx
)
1546 u64 extent_item_pos
;
1548 struct btrfs_key found_key
;
1549 int search_commit_root
= path
->search_commit_root
;
1551 ret
= extent_from_logical(fs_info
, logical
, path
, &found_key
, &flags
);
1552 btrfs_release_path(path
);
1555 if (flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
)
1558 extent_item_pos
= logical
- found_key
.objectid
;
1559 ret
= iterate_extent_inodes(fs_info
, found_key
.objectid
,
1560 extent_item_pos
, search_commit_root
,
1566 typedef int (iterate_irefs_t
)(u64 parent
, u32 name_len
, unsigned long name_off
,
1567 struct extent_buffer
*eb
, void *ctx
);
1569 static int iterate_inode_refs(u64 inum
, struct btrfs_root
*fs_root
,
1570 struct btrfs_path
*path
,
1571 iterate_irefs_t
*iterate
, void *ctx
)
1580 struct extent_buffer
*eb
;
1581 struct btrfs_item
*item
;
1582 struct btrfs_inode_ref
*iref
;
1583 struct btrfs_key found_key
;
1586 path
->leave_spinning
= 1;
1587 ret
= inode_ref_info(inum
, parent
? parent
+1 : 0, fs_root
, path
,
1592 ret
= found
? 0 : -ENOENT
;
1597 parent
= found_key
.offset
;
1598 slot
= path
->slots
[0];
1599 eb
= path
->nodes
[0];
1600 /* make sure we can use eb after releasing the path */
1601 atomic_inc(&eb
->refs
);
1602 btrfs_tree_read_lock(eb
);
1603 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1604 btrfs_release_path(path
);
1606 item
= btrfs_item_nr(eb
, slot
);
1607 iref
= btrfs_item_ptr(eb
, slot
, struct btrfs_inode_ref
);
1609 for (cur
= 0; cur
< btrfs_item_size(eb
, item
); cur
+= len
) {
1610 name_len
= btrfs_inode_ref_name_len(eb
, iref
);
1611 /* path must be released before calling iterate()! */
1612 pr_debug("following ref at offset %u for inode %llu in "
1614 (unsigned long long)found_key
.objectid
,
1615 (unsigned long long)fs_root
->objectid
);
1616 ret
= iterate(parent
, name_len
,
1617 (unsigned long)(iref
+ 1), eb
, ctx
);
1620 len
= sizeof(*iref
) + name_len
;
1621 iref
= (struct btrfs_inode_ref
*)((char *)iref
+ len
);
1623 btrfs_tree_read_unlock_blocking(eb
);
1624 free_extent_buffer(eb
);
1627 btrfs_release_path(path
);
1632 static int iterate_inode_extrefs(u64 inum
, struct btrfs_root
*fs_root
,
1633 struct btrfs_path
*path
,
1634 iterate_irefs_t
*iterate
, void *ctx
)
1641 struct extent_buffer
*eb
;
1642 struct btrfs_inode_extref
*extref
;
1643 struct extent_buffer
*leaf
;
1649 ret
= btrfs_find_one_extref(fs_root
, inum
, offset
, path
, &extref
,
1654 ret
= found
? 0 : -ENOENT
;
1659 slot
= path
->slots
[0];
1660 eb
= path
->nodes
[0];
1661 /* make sure we can use eb after releasing the path */
1662 atomic_inc(&eb
->refs
);
1664 btrfs_tree_read_lock(eb
);
1665 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1666 btrfs_release_path(path
);
1668 leaf
= path
->nodes
[0];
1669 item_size
= btrfs_item_size_nr(leaf
, path
->slots
[0]);
1670 ptr
= btrfs_item_ptr_offset(leaf
, path
->slots
[0]);
1673 while (cur_offset
< item_size
) {
1676 extref
= (struct btrfs_inode_extref
*)(ptr
+ cur_offset
);
1677 parent
= btrfs_inode_extref_parent(eb
, extref
);
1678 name_len
= btrfs_inode_extref_name_len(eb
, extref
);
1679 ret
= iterate(parent
, name_len
,
1680 (unsigned long)&extref
->name
, eb
, ctx
);
1684 cur_offset
+= btrfs_inode_extref_name_len(leaf
, extref
);
1685 cur_offset
+= sizeof(*extref
);
1687 btrfs_tree_read_unlock_blocking(eb
);
1688 free_extent_buffer(eb
);
1693 btrfs_release_path(path
);
1698 static int iterate_irefs(u64 inum
, struct btrfs_root
*fs_root
,
1699 struct btrfs_path
*path
, iterate_irefs_t
*iterate
,
1705 ret
= iterate_inode_refs(inum
, fs_root
, path
, iterate
, ctx
);
1708 else if (ret
!= -ENOENT
)
1711 ret
= iterate_inode_extrefs(inum
, fs_root
, path
, iterate
, ctx
);
1712 if (ret
== -ENOENT
&& found_refs
)
1719 * returns 0 if the path could be dumped (probably truncated)
1720 * returns <0 in case of an error
1722 static int inode_to_path(u64 inum
, u32 name_len
, unsigned long name_off
,
1723 struct extent_buffer
*eb
, void *ctx
)
1725 struct inode_fs_paths
*ipath
= ctx
;
1728 int i
= ipath
->fspath
->elem_cnt
;
1729 const int s_ptr
= sizeof(char *);
1732 bytes_left
= ipath
->fspath
->bytes_left
> s_ptr
?
1733 ipath
->fspath
->bytes_left
- s_ptr
: 0;
1735 fspath_min
= (char *)ipath
->fspath
->val
+ (i
+ 1) * s_ptr
;
1736 fspath
= btrfs_ref_to_path(ipath
->fs_root
, ipath
->btrfs_path
, name_len
,
1737 name_off
, eb
, inum
, fspath_min
, bytes_left
);
1739 return PTR_ERR(fspath
);
1741 if (fspath
> fspath_min
) {
1742 ipath
->fspath
->val
[i
] = (u64
)(unsigned long)fspath
;
1743 ++ipath
->fspath
->elem_cnt
;
1744 ipath
->fspath
->bytes_left
= fspath
- fspath_min
;
1746 ++ipath
->fspath
->elem_missed
;
1747 ipath
->fspath
->bytes_missing
+= fspath_min
- fspath
;
1748 ipath
->fspath
->bytes_left
= 0;
1755 * this dumps all file system paths to the inode into the ipath struct, provided
1756 * is has been created large enough. each path is zero-terminated and accessed
1757 * from ipath->fspath->val[i].
1758 * when it returns, there are ipath->fspath->elem_cnt number of paths available
1759 * in ipath->fspath->val[]. when the allocated space wasn't sufficient, the
1760 * number of missed paths in recored in ipath->fspath->elem_missed, otherwise,
1761 * it's zero. ipath->fspath->bytes_missing holds the number of bytes that would
1762 * have been needed to return all paths.
1764 int paths_from_inode(u64 inum
, struct inode_fs_paths
*ipath
)
1766 return iterate_irefs(inum
, ipath
->fs_root
, ipath
->btrfs_path
,
1767 inode_to_path
, ipath
);
1770 struct btrfs_data_container
*init_data_container(u32 total_bytes
)
1772 struct btrfs_data_container
*data
;
1775 alloc_bytes
= max_t(size_t, total_bytes
, sizeof(*data
));
1776 data
= vmalloc(alloc_bytes
);
1778 return ERR_PTR(-ENOMEM
);
1780 if (total_bytes
>= sizeof(*data
)) {
1781 data
->bytes_left
= total_bytes
- sizeof(*data
);
1782 data
->bytes_missing
= 0;
1784 data
->bytes_missing
= sizeof(*data
) - total_bytes
;
1785 data
->bytes_left
= 0;
1789 data
->elem_missed
= 0;
1795 * allocates space to return multiple file system paths for an inode.
1796 * total_bytes to allocate are passed, note that space usable for actual path
1797 * information will be total_bytes - sizeof(struct inode_fs_paths).
1798 * the returned pointer must be freed with free_ipath() in the end.
1800 struct inode_fs_paths
*init_ipath(s32 total_bytes
, struct btrfs_root
*fs_root
,
1801 struct btrfs_path
*path
)
1803 struct inode_fs_paths
*ifp
;
1804 struct btrfs_data_container
*fspath
;
1806 fspath
= init_data_container(total_bytes
);
1808 return (void *)fspath
;
1810 ifp
= kmalloc(sizeof(*ifp
), GFP_NOFS
);
1813 return ERR_PTR(-ENOMEM
);
1816 ifp
->btrfs_path
= path
;
1817 ifp
->fspath
= fspath
;
1818 ifp
->fs_root
= fs_root
;
1823 void free_ipath(struct inode_fs_paths
*ipath
)
1827 vfree(ipath
->fspath
);