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 void free_inode_elem_list(struct extent_inode_elem
*eie
)
71 struct extent_inode_elem
*eie_next
;
73 for (; eie
; eie
= eie_next
) {
79 static int find_extent_in_eb(struct extent_buffer
*eb
, u64 wanted_disk_byte
,
81 struct extent_inode_elem
**eie
)
85 struct btrfs_file_extent_item
*fi
;
92 * from the shared data ref, we only have the leaf but we need
93 * the key. thus, we must look into all items and see that we
94 * find one (some) with a reference to our extent item.
96 nritems
= btrfs_header_nritems(eb
);
97 for (slot
= 0; slot
< nritems
; ++slot
) {
98 btrfs_item_key_to_cpu(eb
, &key
, slot
);
99 if (key
.type
!= BTRFS_EXTENT_DATA_KEY
)
101 fi
= btrfs_item_ptr(eb
, slot
, struct btrfs_file_extent_item
);
102 extent_type
= btrfs_file_extent_type(eb
, fi
);
103 if (extent_type
== BTRFS_FILE_EXTENT_INLINE
)
105 /* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */
106 disk_byte
= btrfs_file_extent_disk_bytenr(eb
, fi
);
107 if (disk_byte
!= wanted_disk_byte
)
110 ret
= check_extent_in_eb(&key
, eb
, fi
, extent_item_pos
, eie
);
119 * this structure records all encountered refs on the way up to the root
121 struct __prelim_ref
{
122 struct list_head list
;
124 struct btrfs_key key_for_search
;
127 struct extent_inode_elem
*inode_list
;
129 u64 wanted_disk_byte
;
132 static struct kmem_cache
*btrfs_prelim_ref_cache
;
134 int __init
btrfs_prelim_ref_init(void)
136 btrfs_prelim_ref_cache
= kmem_cache_create("btrfs_prelim_ref",
137 sizeof(struct __prelim_ref
),
139 SLAB_RECLAIM_ACCOUNT
| SLAB_MEM_SPREAD
,
141 if (!btrfs_prelim_ref_cache
)
146 void btrfs_prelim_ref_exit(void)
148 if (btrfs_prelim_ref_cache
)
149 kmem_cache_destroy(btrfs_prelim_ref_cache
);
153 * the rules for all callers of this function are:
154 * - obtaining the parent is the goal
155 * - if you add a key, you must know that it is a correct key
156 * - if you cannot add the parent or a correct key, then we will look into the
157 * block later to set a correct key
161 * backref type | shared | indirect | shared | indirect
162 * information | tree | tree | data | data
163 * --------------------+--------+----------+--------+----------
164 * parent logical | y | - | - | -
165 * key to resolve | - | y | y | y
166 * tree block logical | - | - | - | -
167 * root for resolving | y | y | y | y
169 * - column 1: we've the parent -> done
170 * - column 2, 3, 4: we use the key to find the parent
172 * on disk refs (inline or keyed)
173 * ==============================
174 * backref type | shared | indirect | shared | indirect
175 * information | tree | tree | data | data
176 * --------------------+--------+----------+--------+----------
177 * parent logical | y | - | y | -
178 * key to resolve | - | - | - | y
179 * tree block logical | y | y | y | y
180 * root for resolving | - | y | y | y
182 * - column 1, 3: we've the parent -> done
183 * - column 2: we take the first key from the block to find the parent
184 * (see __add_missing_keys)
185 * - column 4: we use the key to find the parent
187 * additional information that's available but not required to find the parent
188 * block might help in merging entries to gain some speed.
191 static int __add_prelim_ref(struct list_head
*head
, u64 root_id
,
192 struct btrfs_key
*key
, int level
,
193 u64 parent
, u64 wanted_disk_byte
, int count
,
196 struct __prelim_ref
*ref
;
198 if (root_id
== BTRFS_DATA_RELOC_TREE_OBJECTID
)
201 ref
= kmem_cache_alloc(btrfs_prelim_ref_cache
, gfp_mask
);
205 ref
->root_id
= root_id
;
207 ref
->key_for_search
= *key
;
209 memset(&ref
->key_for_search
, 0, sizeof(ref
->key_for_search
));
211 ref
->inode_list
= NULL
;
214 ref
->parent
= parent
;
215 ref
->wanted_disk_byte
= wanted_disk_byte
;
216 list_add_tail(&ref
->list
, head
);
221 static int add_all_parents(struct btrfs_root
*root
, struct btrfs_path
*path
,
222 struct ulist
*parents
, struct __prelim_ref
*ref
,
223 int level
, u64 time_seq
, const u64
*extent_item_pos
,
228 struct extent_buffer
*eb
;
229 struct btrfs_key key
;
230 struct btrfs_key
*key_for_search
= &ref
->key_for_search
;
231 struct btrfs_file_extent_item
*fi
;
232 struct extent_inode_elem
*eie
= NULL
, *old
= NULL
;
234 u64 wanted_disk_byte
= ref
->wanted_disk_byte
;
238 eb
= path
->nodes
[level
];
239 ret
= ulist_add(parents
, eb
->start
, 0, GFP_NOFS
);
246 * We normally enter this function with the path already pointing to
247 * the first item to check. But sometimes, we may enter it with
248 * slot==nritems. In that case, go to the next leaf before we continue.
250 if (path
->slots
[0] >= btrfs_header_nritems(path
->nodes
[0]))
251 ret
= btrfs_next_old_leaf(root
, path
, time_seq
);
253 while (!ret
&& count
< total_refs
) {
255 slot
= path
->slots
[0];
257 btrfs_item_key_to_cpu(eb
, &key
, slot
);
259 if (key
.objectid
!= key_for_search
->objectid
||
260 key
.type
!= BTRFS_EXTENT_DATA_KEY
)
263 fi
= btrfs_item_ptr(eb
, slot
, struct btrfs_file_extent_item
);
264 disk_byte
= btrfs_file_extent_disk_bytenr(eb
, fi
);
266 if (disk_byte
== wanted_disk_byte
) {
270 if (extent_item_pos
) {
271 ret
= check_extent_in_eb(&key
, eb
, fi
,
279 ret
= ulist_add_merge_ptr(parents
, eb
->start
,
280 eie
, (void **)&old
, GFP_NOFS
);
283 if (!ret
&& extent_item_pos
) {
291 ret
= btrfs_next_old_item(root
, path
, time_seq
);
297 free_inode_elem_list(eie
);
302 * resolve an indirect backref in the form (root_id, key, level)
303 * to a logical address
305 static int __resolve_indirect_ref(struct btrfs_fs_info
*fs_info
,
306 struct btrfs_path
*path
, u64 time_seq
,
307 struct __prelim_ref
*ref
,
308 struct ulist
*parents
,
309 const u64
*extent_item_pos
, u64 total_refs
)
311 struct btrfs_root
*root
;
312 struct btrfs_key root_key
;
313 struct extent_buffer
*eb
;
316 int level
= ref
->level
;
319 root_key
.objectid
= ref
->root_id
;
320 root_key
.type
= BTRFS_ROOT_ITEM_KEY
;
321 root_key
.offset
= (u64
)-1;
323 index
= srcu_read_lock(&fs_info
->subvol_srcu
);
325 root
= btrfs_read_fs_root_no_name(fs_info
, &root_key
);
327 srcu_read_unlock(&fs_info
->subvol_srcu
, index
);
332 if (path
->search_commit_root
)
333 root_level
= btrfs_header_level(root
->commit_root
);
335 root_level
= btrfs_old_root_level(root
, time_seq
);
337 if (root_level
+ 1 == level
) {
338 srcu_read_unlock(&fs_info
->subvol_srcu
, index
);
342 path
->lowest_level
= level
;
343 ret
= btrfs_search_old_slot(root
, &ref
->key_for_search
, path
, time_seq
);
345 /* root node has been locked, we can release @subvol_srcu safely here */
346 srcu_read_unlock(&fs_info
->subvol_srcu
, index
);
348 pr_debug("search slot in root %llu (level %d, ref count %d) returned "
349 "%d for key (%llu %u %llu)\n",
350 ref
->root_id
, level
, ref
->count
, ret
,
351 ref
->key_for_search
.objectid
, ref
->key_for_search
.type
,
352 ref
->key_for_search
.offset
);
356 eb
= path
->nodes
[level
];
358 if (WARN_ON(!level
)) {
363 eb
= path
->nodes
[level
];
366 ret
= add_all_parents(root
, path
, parents
, ref
, level
, time_seq
,
367 extent_item_pos
, total_refs
);
369 path
->lowest_level
= 0;
370 btrfs_release_path(path
);
375 * resolve all indirect backrefs from the list
377 static int __resolve_indirect_refs(struct btrfs_fs_info
*fs_info
,
378 struct btrfs_path
*path
, u64 time_seq
,
379 struct list_head
*head
,
380 const u64
*extent_item_pos
, u64 total_refs
)
384 struct __prelim_ref
*ref
;
385 struct __prelim_ref
*ref_safe
;
386 struct __prelim_ref
*new_ref
;
387 struct ulist
*parents
;
388 struct ulist_node
*node
;
389 struct ulist_iterator uiter
;
391 parents
= ulist_alloc(GFP_NOFS
);
396 * _safe allows us to insert directly after the current item without
397 * iterating over the newly inserted items.
398 * we're also allowed to re-assign ref during iteration.
400 list_for_each_entry_safe(ref
, ref_safe
, head
, list
) {
401 if (ref
->parent
) /* already direct */
405 err
= __resolve_indirect_ref(fs_info
, path
, time_seq
, ref
,
406 parents
, extent_item_pos
,
409 * we can only tolerate ENOENT,otherwise,we should catch error
410 * and return directly.
412 if (err
== -ENOENT
) {
419 /* we put the first parent into the ref at hand */
420 ULIST_ITER_INIT(&uiter
);
421 node
= ulist_next(parents
, &uiter
);
422 ref
->parent
= node
? node
->val
: 0;
423 ref
->inode_list
= node
?
424 (struct extent_inode_elem
*)(uintptr_t)node
->aux
: NULL
;
426 /* additional parents require new refs being added here */
427 while ((node
= ulist_next(parents
, &uiter
))) {
428 new_ref
= kmem_cache_alloc(btrfs_prelim_ref_cache
,
434 memcpy(new_ref
, ref
, sizeof(*ref
));
435 new_ref
->parent
= node
->val
;
436 new_ref
->inode_list
= (struct extent_inode_elem
*)
437 (uintptr_t)node
->aux
;
438 list_add(&new_ref
->list
, &ref
->list
);
440 ulist_reinit(parents
);
447 static inline int ref_for_same_block(struct __prelim_ref
*ref1
,
448 struct __prelim_ref
*ref2
)
450 if (ref1
->level
!= ref2
->level
)
452 if (ref1
->root_id
!= ref2
->root_id
)
454 if (ref1
->key_for_search
.type
!= ref2
->key_for_search
.type
)
456 if (ref1
->key_for_search
.objectid
!= ref2
->key_for_search
.objectid
)
458 if (ref1
->key_for_search
.offset
!= ref2
->key_for_search
.offset
)
460 if (ref1
->parent
!= ref2
->parent
)
467 * read tree blocks and add keys where required.
469 static int __add_missing_keys(struct btrfs_fs_info
*fs_info
,
470 struct list_head
*head
)
472 struct list_head
*pos
;
473 struct extent_buffer
*eb
;
475 list_for_each(pos
, head
) {
476 struct __prelim_ref
*ref
;
477 ref
= list_entry(pos
, struct __prelim_ref
, list
);
481 if (ref
->key_for_search
.type
)
483 BUG_ON(!ref
->wanted_disk_byte
);
484 eb
= read_tree_block(fs_info
->tree_root
, ref
->wanted_disk_byte
,
485 fs_info
->tree_root
->leafsize
, 0);
486 if (!eb
|| !extent_buffer_uptodate(eb
)) {
487 free_extent_buffer(eb
);
490 btrfs_tree_read_lock(eb
);
491 if (btrfs_header_level(eb
) == 0)
492 btrfs_item_key_to_cpu(eb
, &ref
->key_for_search
, 0);
494 btrfs_node_key_to_cpu(eb
, &ref
->key_for_search
, 0);
495 btrfs_tree_read_unlock(eb
);
496 free_extent_buffer(eb
);
502 * merge two lists of backrefs and adjust counts accordingly
504 * mode = 1: merge identical keys, if key is set
505 * FIXME: if we add more keys in __add_prelim_ref, we can merge more here.
506 * additionally, we could even add a key range for the blocks we
507 * looked into to merge even more (-> replace unresolved refs by those
509 * mode = 2: merge identical parents
511 static void __merge_refs(struct list_head
*head
, int mode
)
513 struct list_head
*pos1
;
515 list_for_each(pos1
, head
) {
516 struct list_head
*n2
;
517 struct list_head
*pos2
;
518 struct __prelim_ref
*ref1
;
520 ref1
= list_entry(pos1
, struct __prelim_ref
, list
);
522 for (pos2
= pos1
->next
, n2
= pos2
->next
; pos2
!= head
;
523 pos2
= n2
, n2
= pos2
->next
) {
524 struct __prelim_ref
*ref2
;
525 struct __prelim_ref
*xchg
;
526 struct extent_inode_elem
*eie
;
528 ref2
= list_entry(pos2
, struct __prelim_ref
, list
);
531 if (!ref_for_same_block(ref1
, ref2
))
533 if (!ref1
->parent
&& ref2
->parent
) {
539 if (ref1
->parent
!= ref2
->parent
)
543 eie
= ref1
->inode_list
;
544 while (eie
&& eie
->next
)
547 eie
->next
= ref2
->inode_list
;
549 ref1
->inode_list
= ref2
->inode_list
;
550 ref1
->count
+= ref2
->count
;
552 list_del(&ref2
->list
);
553 kmem_cache_free(btrfs_prelim_ref_cache
, ref2
);
560 * add all currently queued delayed refs from this head whose seq nr is
561 * smaller or equal that seq to the list
563 static int __add_delayed_refs(struct btrfs_delayed_ref_head
*head
, u64 seq
,
564 struct list_head
*prefs
, u64
*total_refs
)
566 struct btrfs_delayed_extent_op
*extent_op
= head
->extent_op
;
567 struct rb_node
*n
= &head
->node
.rb_node
;
568 struct btrfs_key key
;
569 struct btrfs_key op_key
= {0};
573 if (extent_op
&& extent_op
->update_key
)
574 btrfs_disk_key_to_cpu(&op_key
, &extent_op
->key
);
576 spin_lock(&head
->lock
);
577 n
= rb_first(&head
->ref_root
);
579 struct btrfs_delayed_ref_node
*node
;
580 node
= rb_entry(n
, struct btrfs_delayed_ref_node
,
586 switch (node
->action
) {
587 case BTRFS_ADD_DELAYED_EXTENT
:
588 case BTRFS_UPDATE_DELAYED_HEAD
:
591 case BTRFS_ADD_DELAYED_REF
:
594 case BTRFS_DROP_DELAYED_REF
:
600 *total_refs
+= (node
->ref_mod
* sgn
);
601 switch (node
->type
) {
602 case BTRFS_TREE_BLOCK_REF_KEY
: {
603 struct btrfs_delayed_tree_ref
*ref
;
605 ref
= btrfs_delayed_node_to_tree_ref(node
);
606 ret
= __add_prelim_ref(prefs
, ref
->root
, &op_key
,
607 ref
->level
+ 1, 0, node
->bytenr
,
608 node
->ref_mod
* sgn
, GFP_ATOMIC
);
611 case BTRFS_SHARED_BLOCK_REF_KEY
: {
612 struct btrfs_delayed_tree_ref
*ref
;
614 ref
= btrfs_delayed_node_to_tree_ref(node
);
615 ret
= __add_prelim_ref(prefs
, ref
->root
, NULL
,
616 ref
->level
+ 1, ref
->parent
,
618 node
->ref_mod
* sgn
, GFP_ATOMIC
);
621 case BTRFS_EXTENT_DATA_REF_KEY
: {
622 struct btrfs_delayed_data_ref
*ref
;
623 ref
= btrfs_delayed_node_to_data_ref(node
);
625 key
.objectid
= ref
->objectid
;
626 key
.type
= BTRFS_EXTENT_DATA_KEY
;
627 key
.offset
= ref
->offset
;
628 ret
= __add_prelim_ref(prefs
, ref
->root
, &key
, 0, 0,
630 node
->ref_mod
* sgn
, GFP_ATOMIC
);
633 case BTRFS_SHARED_DATA_REF_KEY
: {
634 struct btrfs_delayed_data_ref
*ref
;
636 ref
= btrfs_delayed_node_to_data_ref(node
);
638 key
.objectid
= ref
->objectid
;
639 key
.type
= BTRFS_EXTENT_DATA_KEY
;
640 key
.offset
= ref
->offset
;
641 ret
= __add_prelim_ref(prefs
, ref
->root
, &key
, 0,
642 ref
->parent
, node
->bytenr
,
643 node
->ref_mod
* sgn
, GFP_ATOMIC
);
652 spin_unlock(&head
->lock
);
657 * add all inline backrefs for bytenr to the list
659 static int __add_inline_refs(struct btrfs_fs_info
*fs_info
,
660 struct btrfs_path
*path
, u64 bytenr
,
661 int *info_level
, struct list_head
*prefs
,
666 struct extent_buffer
*leaf
;
667 struct btrfs_key key
;
668 struct btrfs_key found_key
;
671 struct btrfs_extent_item
*ei
;
676 * enumerate all inline refs
678 leaf
= path
->nodes
[0];
679 slot
= path
->slots
[0];
681 item_size
= btrfs_item_size_nr(leaf
, slot
);
682 BUG_ON(item_size
< sizeof(*ei
));
684 ei
= btrfs_item_ptr(leaf
, slot
, struct btrfs_extent_item
);
685 flags
= btrfs_extent_flags(leaf
, ei
);
686 *total_refs
+= btrfs_extent_refs(leaf
, ei
);
687 btrfs_item_key_to_cpu(leaf
, &found_key
, slot
);
689 ptr
= (unsigned long)(ei
+ 1);
690 end
= (unsigned long)ei
+ item_size
;
692 if (found_key
.type
== BTRFS_EXTENT_ITEM_KEY
&&
693 flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
) {
694 struct btrfs_tree_block_info
*info
;
696 info
= (struct btrfs_tree_block_info
*)ptr
;
697 *info_level
= btrfs_tree_block_level(leaf
, info
);
698 ptr
+= sizeof(struct btrfs_tree_block_info
);
700 } else if (found_key
.type
== BTRFS_METADATA_ITEM_KEY
) {
701 *info_level
= found_key
.offset
;
703 BUG_ON(!(flags
& BTRFS_EXTENT_FLAG_DATA
));
707 struct btrfs_extent_inline_ref
*iref
;
711 iref
= (struct btrfs_extent_inline_ref
*)ptr
;
712 type
= btrfs_extent_inline_ref_type(leaf
, iref
);
713 offset
= btrfs_extent_inline_ref_offset(leaf
, iref
);
716 case BTRFS_SHARED_BLOCK_REF_KEY
:
717 ret
= __add_prelim_ref(prefs
, 0, NULL
,
718 *info_level
+ 1, offset
,
719 bytenr
, 1, GFP_NOFS
);
721 case BTRFS_SHARED_DATA_REF_KEY
: {
722 struct btrfs_shared_data_ref
*sdref
;
725 sdref
= (struct btrfs_shared_data_ref
*)(iref
+ 1);
726 count
= btrfs_shared_data_ref_count(leaf
, sdref
);
727 ret
= __add_prelim_ref(prefs
, 0, NULL
, 0, offset
,
728 bytenr
, count
, GFP_NOFS
);
731 case BTRFS_TREE_BLOCK_REF_KEY
:
732 ret
= __add_prelim_ref(prefs
, offset
, NULL
,
734 bytenr
, 1, GFP_NOFS
);
736 case BTRFS_EXTENT_DATA_REF_KEY
: {
737 struct btrfs_extent_data_ref
*dref
;
741 dref
= (struct btrfs_extent_data_ref
*)(&iref
->offset
);
742 count
= btrfs_extent_data_ref_count(leaf
, dref
);
743 key
.objectid
= btrfs_extent_data_ref_objectid(leaf
,
745 key
.type
= BTRFS_EXTENT_DATA_KEY
;
746 key
.offset
= btrfs_extent_data_ref_offset(leaf
, dref
);
747 root
= btrfs_extent_data_ref_root(leaf
, dref
);
748 ret
= __add_prelim_ref(prefs
, root
, &key
, 0, 0,
749 bytenr
, count
, GFP_NOFS
);
757 ptr
+= btrfs_extent_inline_ref_size(type
);
764 * add all non-inline backrefs for bytenr to the list
766 static int __add_keyed_refs(struct btrfs_fs_info
*fs_info
,
767 struct btrfs_path
*path
, u64 bytenr
,
768 int info_level
, struct list_head
*prefs
)
770 struct btrfs_root
*extent_root
= fs_info
->extent_root
;
773 struct extent_buffer
*leaf
;
774 struct btrfs_key key
;
777 ret
= btrfs_next_item(extent_root
, path
);
785 slot
= path
->slots
[0];
786 leaf
= path
->nodes
[0];
787 btrfs_item_key_to_cpu(leaf
, &key
, slot
);
789 if (key
.objectid
!= bytenr
)
791 if (key
.type
< BTRFS_TREE_BLOCK_REF_KEY
)
793 if (key
.type
> BTRFS_SHARED_DATA_REF_KEY
)
797 case BTRFS_SHARED_BLOCK_REF_KEY
:
798 ret
= __add_prelim_ref(prefs
, 0, NULL
,
799 info_level
+ 1, key
.offset
,
800 bytenr
, 1, GFP_NOFS
);
802 case BTRFS_SHARED_DATA_REF_KEY
: {
803 struct btrfs_shared_data_ref
*sdref
;
806 sdref
= btrfs_item_ptr(leaf
, slot
,
807 struct btrfs_shared_data_ref
);
808 count
= btrfs_shared_data_ref_count(leaf
, sdref
);
809 ret
= __add_prelim_ref(prefs
, 0, NULL
, 0, key
.offset
,
810 bytenr
, count
, GFP_NOFS
);
813 case BTRFS_TREE_BLOCK_REF_KEY
:
814 ret
= __add_prelim_ref(prefs
, key
.offset
, NULL
,
816 bytenr
, 1, GFP_NOFS
);
818 case BTRFS_EXTENT_DATA_REF_KEY
: {
819 struct btrfs_extent_data_ref
*dref
;
823 dref
= btrfs_item_ptr(leaf
, slot
,
824 struct btrfs_extent_data_ref
);
825 count
= btrfs_extent_data_ref_count(leaf
, dref
);
826 key
.objectid
= btrfs_extent_data_ref_objectid(leaf
,
828 key
.type
= BTRFS_EXTENT_DATA_KEY
;
829 key
.offset
= btrfs_extent_data_ref_offset(leaf
, dref
);
830 root
= btrfs_extent_data_ref_root(leaf
, dref
);
831 ret
= __add_prelim_ref(prefs
, root
, &key
, 0, 0,
832 bytenr
, count
, GFP_NOFS
);
847 * this adds all existing backrefs (inline backrefs, backrefs and delayed
848 * refs) for the given bytenr to the refs list, merges duplicates and resolves
849 * indirect refs to their parent bytenr.
850 * When roots are found, they're added to the roots list
852 * FIXME some caching might speed things up
854 static int find_parent_nodes(struct btrfs_trans_handle
*trans
,
855 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
856 u64 time_seq
, struct ulist
*refs
,
857 struct ulist
*roots
, const u64
*extent_item_pos
)
859 struct btrfs_key key
;
860 struct btrfs_path
*path
;
861 struct btrfs_delayed_ref_root
*delayed_refs
= NULL
;
862 struct btrfs_delayed_ref_head
*head
;
865 struct list_head prefs_delayed
;
866 struct list_head prefs
;
867 struct __prelim_ref
*ref
;
868 struct extent_inode_elem
*eie
= NULL
;
871 INIT_LIST_HEAD(&prefs
);
872 INIT_LIST_HEAD(&prefs_delayed
);
874 key
.objectid
= bytenr
;
875 key
.offset
= (u64
)-1;
876 if (btrfs_fs_incompat(fs_info
, SKINNY_METADATA
))
877 key
.type
= BTRFS_METADATA_ITEM_KEY
;
879 key
.type
= BTRFS_EXTENT_ITEM_KEY
;
881 path
= btrfs_alloc_path();
885 path
->search_commit_root
= 1;
886 path
->skip_locking
= 1;
890 * grab both a lock on the path and a lock on the delayed ref head.
891 * We need both to get a consistent picture of how the refs look
892 * at a specified point in time
897 ret
= btrfs_search_slot(trans
, fs_info
->extent_root
, &key
, path
, 0, 0);
902 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
903 if (trans
&& likely(trans
->type
!= __TRANS_DUMMY
)) {
908 * look if there are updates for this ref queued and lock the
911 delayed_refs
= &trans
->transaction
->delayed_refs
;
912 spin_lock(&delayed_refs
->lock
);
913 head
= btrfs_find_delayed_ref_head(trans
, bytenr
);
915 if (!mutex_trylock(&head
->mutex
)) {
916 atomic_inc(&head
->node
.refs
);
917 spin_unlock(&delayed_refs
->lock
);
919 btrfs_release_path(path
);
922 * Mutex was contended, block until it's
923 * released and try again
925 mutex_lock(&head
->mutex
);
926 mutex_unlock(&head
->mutex
);
927 btrfs_put_delayed_ref(&head
->node
);
930 spin_unlock(&delayed_refs
->lock
);
931 ret
= __add_delayed_refs(head
, time_seq
,
932 &prefs_delayed
, &total_refs
);
933 mutex_unlock(&head
->mutex
);
937 spin_unlock(&delayed_refs
->lock
);
941 if (path
->slots
[0]) {
942 struct extent_buffer
*leaf
;
946 leaf
= path
->nodes
[0];
947 slot
= path
->slots
[0];
948 btrfs_item_key_to_cpu(leaf
, &key
, slot
);
949 if (key
.objectid
== bytenr
&&
950 (key
.type
== BTRFS_EXTENT_ITEM_KEY
||
951 key
.type
== BTRFS_METADATA_ITEM_KEY
)) {
952 ret
= __add_inline_refs(fs_info
, path
, bytenr
,
957 ret
= __add_keyed_refs(fs_info
, path
, bytenr
,
963 btrfs_release_path(path
);
965 list_splice_init(&prefs_delayed
, &prefs
);
967 ret
= __add_missing_keys(fs_info
, &prefs
);
971 __merge_refs(&prefs
, 1);
973 ret
= __resolve_indirect_refs(fs_info
, path
, time_seq
, &prefs
,
974 extent_item_pos
, total_refs
);
978 __merge_refs(&prefs
, 2);
980 while (!list_empty(&prefs
)) {
981 ref
= list_first_entry(&prefs
, struct __prelim_ref
, list
);
982 WARN_ON(ref
->count
< 0);
983 if (roots
&& ref
->count
&& ref
->root_id
&& ref
->parent
== 0) {
984 /* no parent == root of tree */
985 ret
= ulist_add(roots
, ref
->root_id
, 0, GFP_NOFS
);
989 if (ref
->count
&& ref
->parent
) {
990 if (extent_item_pos
&& !ref
->inode_list
&&
993 struct extent_buffer
*eb
;
994 bsz
= btrfs_level_size(fs_info
->extent_root
,
996 eb
= read_tree_block(fs_info
->extent_root
,
997 ref
->parent
, bsz
, 0);
998 if (!eb
|| !extent_buffer_uptodate(eb
)) {
999 free_extent_buffer(eb
);
1003 btrfs_tree_read_lock(eb
);
1004 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1005 ret
= find_extent_in_eb(eb
, bytenr
,
1006 *extent_item_pos
, &eie
);
1007 btrfs_tree_read_unlock_blocking(eb
);
1008 free_extent_buffer(eb
);
1011 ref
->inode_list
= eie
;
1013 ret
= ulist_add_merge_ptr(refs
, ref
->parent
,
1015 (void **)&eie
, GFP_NOFS
);
1018 if (!ret
&& extent_item_pos
) {
1020 * we've recorded that parent, so we must extend
1021 * its inode list here
1026 eie
->next
= ref
->inode_list
;
1030 list_del(&ref
->list
);
1031 kmem_cache_free(btrfs_prelim_ref_cache
, ref
);
1035 btrfs_free_path(path
);
1036 while (!list_empty(&prefs
)) {
1037 ref
= list_first_entry(&prefs
, struct __prelim_ref
, list
);
1038 list_del(&ref
->list
);
1039 kmem_cache_free(btrfs_prelim_ref_cache
, ref
);
1041 while (!list_empty(&prefs_delayed
)) {
1042 ref
= list_first_entry(&prefs_delayed
, struct __prelim_ref
,
1044 list_del(&ref
->list
);
1045 kmem_cache_free(btrfs_prelim_ref_cache
, ref
);
1048 free_inode_elem_list(eie
);
1052 static void free_leaf_list(struct ulist
*blocks
)
1054 struct ulist_node
*node
= NULL
;
1055 struct extent_inode_elem
*eie
;
1056 struct ulist_iterator uiter
;
1058 ULIST_ITER_INIT(&uiter
);
1059 while ((node
= ulist_next(blocks
, &uiter
))) {
1062 eie
= (struct extent_inode_elem
*)(uintptr_t)node
->aux
;
1063 free_inode_elem_list(eie
);
1071 * Finds all leafs with a reference to the specified combination of bytenr and
1072 * offset. key_list_head will point to a list of corresponding keys (caller must
1073 * free each list element). The leafs will be stored in the leafs ulist, which
1074 * must be freed with ulist_free.
1076 * returns 0 on success, <0 on error
1078 static int btrfs_find_all_leafs(struct btrfs_trans_handle
*trans
,
1079 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
1080 u64 time_seq
, struct ulist
**leafs
,
1081 const u64
*extent_item_pos
)
1085 *leafs
= ulist_alloc(GFP_NOFS
);
1089 ret
= find_parent_nodes(trans
, fs_info
, bytenr
,
1090 time_seq
, *leafs
, NULL
, extent_item_pos
);
1091 if (ret
< 0 && ret
!= -ENOENT
) {
1092 free_leaf_list(*leafs
);
1100 * walk all backrefs for a given extent to find all roots that reference this
1101 * extent. Walking a backref means finding all extents that reference this
1102 * extent and in turn walk the backrefs of those, too. Naturally this is a
1103 * recursive process, but here it is implemented in an iterative fashion: We
1104 * find all referencing extents for the extent in question and put them on a
1105 * list. In turn, we find all referencing extents for those, further appending
1106 * to the list. The way we iterate the list allows adding more elements after
1107 * the current while iterating. The process stops when we reach the end of the
1108 * list. Found roots are added to the roots list.
1110 * returns 0 on success, < 0 on error.
1112 static int __btrfs_find_all_roots(struct btrfs_trans_handle
*trans
,
1113 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
1114 u64 time_seq
, struct ulist
**roots
)
1117 struct ulist_node
*node
= NULL
;
1118 struct ulist_iterator uiter
;
1121 tmp
= ulist_alloc(GFP_NOFS
);
1124 *roots
= ulist_alloc(GFP_NOFS
);
1130 ULIST_ITER_INIT(&uiter
);
1132 ret
= find_parent_nodes(trans
, fs_info
, bytenr
,
1133 time_seq
, tmp
, *roots
, NULL
);
1134 if (ret
< 0 && ret
!= -ENOENT
) {
1139 node
= ulist_next(tmp
, &uiter
);
1150 int btrfs_find_all_roots(struct btrfs_trans_handle
*trans
,
1151 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
1152 u64 time_seq
, struct ulist
**roots
)
1157 down_read(&fs_info
->commit_root_sem
);
1158 ret
= __btrfs_find_all_roots(trans
, fs_info
, bytenr
, time_seq
, roots
);
1160 up_read(&fs_info
->commit_root_sem
);
1165 * this makes the path point to (inum INODE_ITEM ioff)
1167 int inode_item_info(u64 inum
, u64 ioff
, struct btrfs_root
*fs_root
,
1168 struct btrfs_path
*path
)
1170 struct btrfs_key key
;
1171 return btrfs_find_item(fs_root
, path
, inum
, ioff
,
1172 BTRFS_INODE_ITEM_KEY
, &key
);
1175 static int inode_ref_info(u64 inum
, u64 ioff
, struct btrfs_root
*fs_root
,
1176 struct btrfs_path
*path
,
1177 struct btrfs_key
*found_key
)
1179 return btrfs_find_item(fs_root
, path
, inum
, ioff
,
1180 BTRFS_INODE_REF_KEY
, found_key
);
1183 int btrfs_find_one_extref(struct btrfs_root
*root
, u64 inode_objectid
,
1184 u64 start_off
, struct btrfs_path
*path
,
1185 struct btrfs_inode_extref
**ret_extref
,
1189 struct btrfs_key key
;
1190 struct btrfs_key found_key
;
1191 struct btrfs_inode_extref
*extref
;
1192 struct extent_buffer
*leaf
;
1195 key
.objectid
= inode_objectid
;
1196 btrfs_set_key_type(&key
, BTRFS_INODE_EXTREF_KEY
);
1197 key
.offset
= start_off
;
1199 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
1204 leaf
= path
->nodes
[0];
1205 slot
= path
->slots
[0];
1206 if (slot
>= btrfs_header_nritems(leaf
)) {
1208 * If the item at offset is not found,
1209 * btrfs_search_slot will point us to the slot
1210 * where it should be inserted. In our case
1211 * that will be the slot directly before the
1212 * next INODE_REF_KEY_V2 item. In the case
1213 * that we're pointing to the last slot in a
1214 * leaf, we must move one leaf over.
1216 ret
= btrfs_next_leaf(root
, path
);
1225 btrfs_item_key_to_cpu(leaf
, &found_key
, slot
);
1228 * Check that we're still looking at an extended ref key for
1229 * this particular objectid. If we have different
1230 * objectid or type then there are no more to be found
1231 * in the tree and we can exit.
1234 if (found_key
.objectid
!= inode_objectid
)
1236 if (btrfs_key_type(&found_key
) != BTRFS_INODE_EXTREF_KEY
)
1240 ptr
= btrfs_item_ptr_offset(leaf
, path
->slots
[0]);
1241 extref
= (struct btrfs_inode_extref
*)ptr
;
1242 *ret_extref
= extref
;
1244 *found_off
= found_key
.offset
;
1252 * this iterates to turn a name (from iref/extref) into a full filesystem path.
1253 * Elements 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_ref_to_path(struct btrfs_root
*fs_root
, struct btrfs_path
*path
,
1266 u32 name_len
, unsigned long name_off
,
1267 struct extent_buffer
*eb_in
, u64 parent
,
1268 char *dest
, u32 size
)
1273 s64 bytes_left
= ((s64
)size
) - 1;
1274 struct extent_buffer
*eb
= eb_in
;
1275 struct btrfs_key found_key
;
1276 int leave_spinning
= path
->leave_spinning
;
1277 struct btrfs_inode_ref
*iref
;
1279 if (bytes_left
>= 0)
1280 dest
[bytes_left
] = '\0';
1282 path
->leave_spinning
= 1;
1284 bytes_left
-= name_len
;
1285 if (bytes_left
>= 0)
1286 read_extent_buffer(eb
, dest
+ bytes_left
,
1287 name_off
, name_len
);
1289 btrfs_tree_read_unlock_blocking(eb
);
1290 free_extent_buffer(eb
);
1292 ret
= inode_ref_info(parent
, 0, fs_root
, path
, &found_key
);
1298 next_inum
= found_key
.offset
;
1300 /* regular exit ahead */
1301 if (parent
== next_inum
)
1304 slot
= path
->slots
[0];
1305 eb
= path
->nodes
[0];
1306 /* make sure we can use eb after releasing the path */
1308 atomic_inc(&eb
->refs
);
1309 btrfs_tree_read_lock(eb
);
1310 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1312 btrfs_release_path(path
);
1313 iref
= btrfs_item_ptr(eb
, slot
, struct btrfs_inode_ref
);
1315 name_len
= btrfs_inode_ref_name_len(eb
, iref
);
1316 name_off
= (unsigned long)(iref
+ 1);
1320 if (bytes_left
>= 0)
1321 dest
[bytes_left
] = '/';
1324 btrfs_release_path(path
);
1325 path
->leave_spinning
= leave_spinning
;
1328 return ERR_PTR(ret
);
1330 return dest
+ bytes_left
;
1334 * this makes the path point to (logical EXTENT_ITEM *)
1335 * returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for
1336 * tree blocks and <0 on error.
1338 int extent_from_logical(struct btrfs_fs_info
*fs_info
, u64 logical
,
1339 struct btrfs_path
*path
, struct btrfs_key
*found_key
,
1346 struct extent_buffer
*eb
;
1347 struct btrfs_extent_item
*ei
;
1348 struct btrfs_key key
;
1350 if (btrfs_fs_incompat(fs_info
, SKINNY_METADATA
))
1351 key
.type
= BTRFS_METADATA_ITEM_KEY
;
1353 key
.type
= BTRFS_EXTENT_ITEM_KEY
;
1354 key
.objectid
= logical
;
1355 key
.offset
= (u64
)-1;
1357 ret
= btrfs_search_slot(NULL
, fs_info
->extent_root
, &key
, path
, 0, 0);
1361 ret
= btrfs_previous_extent_item(fs_info
->extent_root
, path
, 0);
1367 btrfs_item_key_to_cpu(path
->nodes
[0], found_key
, path
->slots
[0]);
1368 if (found_key
->type
== BTRFS_METADATA_ITEM_KEY
)
1369 size
= fs_info
->extent_root
->leafsize
;
1370 else if (found_key
->type
== BTRFS_EXTENT_ITEM_KEY
)
1371 size
= found_key
->offset
;
1373 if (found_key
->objectid
> logical
||
1374 found_key
->objectid
+ size
<= logical
) {
1375 pr_debug("logical %llu is not within any extent\n", logical
);
1379 eb
= path
->nodes
[0];
1380 item_size
= btrfs_item_size_nr(eb
, path
->slots
[0]);
1381 BUG_ON(item_size
< sizeof(*ei
));
1383 ei
= btrfs_item_ptr(eb
, path
->slots
[0], struct btrfs_extent_item
);
1384 flags
= btrfs_extent_flags(eb
, ei
);
1386 pr_debug("logical %llu is at position %llu within the extent (%llu "
1387 "EXTENT_ITEM %llu) flags %#llx size %u\n",
1388 logical
, logical
- found_key
->objectid
, found_key
->objectid
,
1389 found_key
->offset
, flags
, item_size
);
1391 WARN_ON(!flags_ret
);
1393 if (flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
)
1394 *flags_ret
= BTRFS_EXTENT_FLAG_TREE_BLOCK
;
1395 else if (flags
& BTRFS_EXTENT_FLAG_DATA
)
1396 *flags_ret
= BTRFS_EXTENT_FLAG_DATA
;
1406 * helper function to iterate extent inline refs. ptr must point to a 0 value
1407 * for the first call and may be modified. it is used to track state.
1408 * if more refs exist, 0 is returned and the next call to
1409 * __get_extent_inline_ref must pass the modified ptr parameter to get the
1410 * next ref. after the last ref was processed, 1 is returned.
1411 * returns <0 on error
1413 static int __get_extent_inline_ref(unsigned long *ptr
, struct extent_buffer
*eb
,
1414 struct btrfs_key
*key
,
1415 struct btrfs_extent_item
*ei
, u32 item_size
,
1416 struct btrfs_extent_inline_ref
**out_eiref
,
1421 struct btrfs_tree_block_info
*info
;
1425 flags
= btrfs_extent_flags(eb
, ei
);
1426 if (flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
) {
1427 if (key
->type
== BTRFS_METADATA_ITEM_KEY
) {
1428 /* a skinny metadata extent */
1430 (struct btrfs_extent_inline_ref
*)(ei
+ 1);
1432 WARN_ON(key
->type
!= BTRFS_EXTENT_ITEM_KEY
);
1433 info
= (struct btrfs_tree_block_info
*)(ei
+ 1);
1435 (struct btrfs_extent_inline_ref
*)(info
+ 1);
1438 *out_eiref
= (struct btrfs_extent_inline_ref
*)(ei
+ 1);
1440 *ptr
= (unsigned long)*out_eiref
;
1441 if ((unsigned long)(*ptr
) >= (unsigned long)ei
+ item_size
)
1445 end
= (unsigned long)ei
+ item_size
;
1446 *out_eiref
= (struct btrfs_extent_inline_ref
*)(*ptr
);
1447 *out_type
= btrfs_extent_inline_ref_type(eb
, *out_eiref
);
1449 *ptr
+= btrfs_extent_inline_ref_size(*out_type
);
1450 WARN_ON(*ptr
> end
);
1452 return 1; /* last */
1458 * reads the tree block backref for an extent. tree level and root are returned
1459 * through out_level and out_root. ptr must point to a 0 value for the first
1460 * call and may be modified (see __get_extent_inline_ref comment).
1461 * returns 0 if data was provided, 1 if there was no more data to provide or
1464 int tree_backref_for_extent(unsigned long *ptr
, struct extent_buffer
*eb
,
1465 struct btrfs_key
*key
, struct btrfs_extent_item
*ei
,
1466 u32 item_size
, u64
*out_root
, u8
*out_level
)
1470 struct btrfs_tree_block_info
*info
;
1471 struct btrfs_extent_inline_ref
*eiref
;
1473 if (*ptr
== (unsigned long)-1)
1477 ret
= __get_extent_inline_ref(ptr
, eb
, key
, ei
, item_size
,
1482 if (type
== BTRFS_TREE_BLOCK_REF_KEY
||
1483 type
== BTRFS_SHARED_BLOCK_REF_KEY
)
1490 /* we can treat both ref types equally here */
1491 info
= (struct btrfs_tree_block_info
*)(ei
+ 1);
1492 *out_root
= btrfs_extent_inline_ref_offset(eb
, eiref
);
1493 *out_level
= btrfs_tree_block_level(eb
, info
);
1496 *ptr
= (unsigned long)-1;
1501 static int iterate_leaf_refs(struct extent_inode_elem
*inode_list
,
1502 u64 root
, u64 extent_item_objectid
,
1503 iterate_extent_inodes_t
*iterate
, void *ctx
)
1505 struct extent_inode_elem
*eie
;
1508 for (eie
= inode_list
; eie
; eie
= eie
->next
) {
1509 pr_debug("ref for %llu resolved, key (%llu EXTEND_DATA %llu), "
1510 "root %llu\n", extent_item_objectid
,
1511 eie
->inum
, eie
->offset
, root
);
1512 ret
= iterate(eie
->inum
, eie
->offset
, root
, ctx
);
1514 pr_debug("stopping iteration for %llu due to ret=%d\n",
1515 extent_item_objectid
, ret
);
1524 * calls iterate() for every inode that references the extent identified by
1525 * the given parameters.
1526 * when the iterator function returns a non-zero value, iteration stops.
1528 int iterate_extent_inodes(struct btrfs_fs_info
*fs_info
,
1529 u64 extent_item_objectid
, u64 extent_item_pos
,
1530 int search_commit_root
,
1531 iterate_extent_inodes_t
*iterate
, void *ctx
)
1534 struct btrfs_trans_handle
*trans
= NULL
;
1535 struct ulist
*refs
= NULL
;
1536 struct ulist
*roots
= NULL
;
1537 struct ulist_node
*ref_node
= NULL
;
1538 struct ulist_node
*root_node
= NULL
;
1539 struct seq_list tree_mod_seq_elem
= {};
1540 struct ulist_iterator ref_uiter
;
1541 struct ulist_iterator root_uiter
;
1543 pr_debug("resolving all inodes for extent %llu\n",
1544 extent_item_objectid
);
1546 if (!search_commit_root
) {
1547 trans
= btrfs_join_transaction(fs_info
->extent_root
);
1549 return PTR_ERR(trans
);
1550 btrfs_get_tree_mod_seq(fs_info
, &tree_mod_seq_elem
);
1552 down_read(&fs_info
->commit_root_sem
);
1555 ret
= btrfs_find_all_leafs(trans
, fs_info
, extent_item_objectid
,
1556 tree_mod_seq_elem
.seq
, &refs
,
1561 ULIST_ITER_INIT(&ref_uiter
);
1562 while (!ret
&& (ref_node
= ulist_next(refs
, &ref_uiter
))) {
1563 ret
= __btrfs_find_all_roots(trans
, fs_info
, ref_node
->val
,
1564 tree_mod_seq_elem
.seq
, &roots
);
1567 ULIST_ITER_INIT(&root_uiter
);
1568 while (!ret
&& (root_node
= ulist_next(roots
, &root_uiter
))) {
1569 pr_debug("root %llu references leaf %llu, data list "
1570 "%#llx\n", root_node
->val
, ref_node
->val
,
1572 ret
= iterate_leaf_refs((struct extent_inode_elem
*)
1573 (uintptr_t)ref_node
->aux
,
1575 extent_item_objectid
,
1581 free_leaf_list(refs
);
1583 if (!search_commit_root
) {
1584 btrfs_put_tree_mod_seq(fs_info
, &tree_mod_seq_elem
);
1585 btrfs_end_transaction(trans
, fs_info
->extent_root
);
1587 up_read(&fs_info
->commit_root_sem
);
1593 int iterate_inodes_from_logical(u64 logical
, struct btrfs_fs_info
*fs_info
,
1594 struct btrfs_path
*path
,
1595 iterate_extent_inodes_t
*iterate
, void *ctx
)
1598 u64 extent_item_pos
;
1600 struct btrfs_key found_key
;
1601 int search_commit_root
= path
->search_commit_root
;
1603 ret
= extent_from_logical(fs_info
, logical
, path
, &found_key
, &flags
);
1604 btrfs_release_path(path
);
1607 if (flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
)
1610 extent_item_pos
= logical
- found_key
.objectid
;
1611 ret
= iterate_extent_inodes(fs_info
, found_key
.objectid
,
1612 extent_item_pos
, search_commit_root
,
1618 typedef int (iterate_irefs_t
)(u64 parent
, u32 name_len
, unsigned long name_off
,
1619 struct extent_buffer
*eb
, void *ctx
);
1621 static int iterate_inode_refs(u64 inum
, struct btrfs_root
*fs_root
,
1622 struct btrfs_path
*path
,
1623 iterate_irefs_t
*iterate
, void *ctx
)
1632 struct extent_buffer
*eb
;
1633 struct btrfs_item
*item
;
1634 struct btrfs_inode_ref
*iref
;
1635 struct btrfs_key found_key
;
1638 ret
= inode_ref_info(inum
, parent
? parent
+1 : 0, fs_root
, path
,
1643 ret
= found
? 0 : -ENOENT
;
1648 parent
= found_key
.offset
;
1649 slot
= path
->slots
[0];
1650 eb
= btrfs_clone_extent_buffer(path
->nodes
[0]);
1655 extent_buffer_get(eb
);
1656 btrfs_tree_read_lock(eb
);
1657 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1658 btrfs_release_path(path
);
1660 item
= btrfs_item_nr(slot
);
1661 iref
= btrfs_item_ptr(eb
, slot
, struct btrfs_inode_ref
);
1663 for (cur
= 0; cur
< btrfs_item_size(eb
, item
); cur
+= len
) {
1664 name_len
= btrfs_inode_ref_name_len(eb
, iref
);
1665 /* path must be released before calling iterate()! */
1666 pr_debug("following ref at offset %u for inode %llu in "
1667 "tree %llu\n", cur
, found_key
.objectid
,
1669 ret
= iterate(parent
, name_len
,
1670 (unsigned long)(iref
+ 1), eb
, ctx
);
1673 len
= sizeof(*iref
) + name_len
;
1674 iref
= (struct btrfs_inode_ref
*)((char *)iref
+ len
);
1676 btrfs_tree_read_unlock_blocking(eb
);
1677 free_extent_buffer(eb
);
1680 btrfs_release_path(path
);
1685 static int iterate_inode_extrefs(u64 inum
, struct btrfs_root
*fs_root
,
1686 struct btrfs_path
*path
,
1687 iterate_irefs_t
*iterate
, void *ctx
)
1694 struct extent_buffer
*eb
;
1695 struct btrfs_inode_extref
*extref
;
1696 struct extent_buffer
*leaf
;
1702 ret
= btrfs_find_one_extref(fs_root
, inum
, offset
, path
, &extref
,
1707 ret
= found
? 0 : -ENOENT
;
1712 slot
= path
->slots
[0];
1713 eb
= btrfs_clone_extent_buffer(path
->nodes
[0]);
1718 extent_buffer_get(eb
);
1720 btrfs_tree_read_lock(eb
);
1721 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1722 btrfs_release_path(path
);
1724 leaf
= path
->nodes
[0];
1725 item_size
= btrfs_item_size_nr(leaf
, slot
);
1726 ptr
= btrfs_item_ptr_offset(leaf
, slot
);
1729 while (cur_offset
< item_size
) {
1732 extref
= (struct btrfs_inode_extref
*)(ptr
+ cur_offset
);
1733 parent
= btrfs_inode_extref_parent(eb
, extref
);
1734 name_len
= btrfs_inode_extref_name_len(eb
, extref
);
1735 ret
= iterate(parent
, name_len
,
1736 (unsigned long)&extref
->name
, eb
, ctx
);
1740 cur_offset
+= btrfs_inode_extref_name_len(leaf
, extref
);
1741 cur_offset
+= sizeof(*extref
);
1743 btrfs_tree_read_unlock_blocking(eb
);
1744 free_extent_buffer(eb
);
1749 btrfs_release_path(path
);
1754 static int iterate_irefs(u64 inum
, struct btrfs_root
*fs_root
,
1755 struct btrfs_path
*path
, iterate_irefs_t
*iterate
,
1761 ret
= iterate_inode_refs(inum
, fs_root
, path
, iterate
, ctx
);
1764 else if (ret
!= -ENOENT
)
1767 ret
= iterate_inode_extrefs(inum
, fs_root
, path
, iterate
, ctx
);
1768 if (ret
== -ENOENT
&& found_refs
)
1775 * returns 0 if the path could be dumped (probably truncated)
1776 * returns <0 in case of an error
1778 static int inode_to_path(u64 inum
, u32 name_len
, unsigned long name_off
,
1779 struct extent_buffer
*eb
, void *ctx
)
1781 struct inode_fs_paths
*ipath
= ctx
;
1784 int i
= ipath
->fspath
->elem_cnt
;
1785 const int s_ptr
= sizeof(char *);
1788 bytes_left
= ipath
->fspath
->bytes_left
> s_ptr
?
1789 ipath
->fspath
->bytes_left
- s_ptr
: 0;
1791 fspath_min
= (char *)ipath
->fspath
->val
+ (i
+ 1) * s_ptr
;
1792 fspath
= btrfs_ref_to_path(ipath
->fs_root
, ipath
->btrfs_path
, name_len
,
1793 name_off
, eb
, inum
, fspath_min
, bytes_left
);
1795 return PTR_ERR(fspath
);
1797 if (fspath
> fspath_min
) {
1798 ipath
->fspath
->val
[i
] = (u64
)(unsigned long)fspath
;
1799 ++ipath
->fspath
->elem_cnt
;
1800 ipath
->fspath
->bytes_left
= fspath
- fspath_min
;
1802 ++ipath
->fspath
->elem_missed
;
1803 ipath
->fspath
->bytes_missing
+= fspath_min
- fspath
;
1804 ipath
->fspath
->bytes_left
= 0;
1811 * this dumps all file system paths to the inode into the ipath struct, provided
1812 * is has been created large enough. each path is zero-terminated and accessed
1813 * from ipath->fspath->val[i].
1814 * when it returns, there are ipath->fspath->elem_cnt number of paths available
1815 * in ipath->fspath->val[]. when the allocated space wasn't sufficient, the
1816 * number of missed paths in recored in ipath->fspath->elem_missed, otherwise,
1817 * it's zero. ipath->fspath->bytes_missing holds the number of bytes that would
1818 * have been needed to return all paths.
1820 int paths_from_inode(u64 inum
, struct inode_fs_paths
*ipath
)
1822 return iterate_irefs(inum
, ipath
->fs_root
, ipath
->btrfs_path
,
1823 inode_to_path
, ipath
);
1826 struct btrfs_data_container
*init_data_container(u32 total_bytes
)
1828 struct btrfs_data_container
*data
;
1831 alloc_bytes
= max_t(size_t, total_bytes
, sizeof(*data
));
1832 data
= vmalloc(alloc_bytes
);
1834 return ERR_PTR(-ENOMEM
);
1836 if (total_bytes
>= sizeof(*data
)) {
1837 data
->bytes_left
= total_bytes
- sizeof(*data
);
1838 data
->bytes_missing
= 0;
1840 data
->bytes_missing
= sizeof(*data
) - total_bytes
;
1841 data
->bytes_left
= 0;
1845 data
->elem_missed
= 0;
1851 * allocates space to return multiple file system paths for an inode.
1852 * total_bytes to allocate are passed, note that space usable for actual path
1853 * information will be total_bytes - sizeof(struct inode_fs_paths).
1854 * the returned pointer must be freed with free_ipath() in the end.
1856 struct inode_fs_paths
*init_ipath(s32 total_bytes
, struct btrfs_root
*fs_root
,
1857 struct btrfs_path
*path
)
1859 struct inode_fs_paths
*ifp
;
1860 struct btrfs_data_container
*fspath
;
1862 fspath
= init_data_container(total_bytes
);
1864 return (void *)fspath
;
1866 ifp
= kmalloc(sizeof(*ifp
), GFP_NOFS
);
1869 return ERR_PTR(-ENOMEM
);
1872 ifp
->btrfs_path
= path
;
1873 ifp
->fspath
= fspath
;
1874 ifp
->fs_root
= fs_root
;
1879 void free_ipath(struct inode_fs_paths
*ipath
)
1883 vfree(ipath
->fspath
);