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
;
122 static struct kmem_cache
*btrfs_prelim_ref_cache
;
124 int __init
btrfs_prelim_ref_init(void)
126 btrfs_prelim_ref_cache
= kmem_cache_create("btrfs_prelim_ref",
127 sizeof(struct __prelim_ref
),
129 SLAB_RECLAIM_ACCOUNT
| SLAB_MEM_SPREAD
,
131 if (!btrfs_prelim_ref_cache
)
136 void btrfs_prelim_ref_exit(void)
138 if (btrfs_prelim_ref_cache
)
139 kmem_cache_destroy(btrfs_prelim_ref_cache
);
143 * the rules for all callers of this function are:
144 * - obtaining the parent is the goal
145 * - if you add a key, you must know that it is a correct key
146 * - if you cannot add the parent or a correct key, then we will look into the
147 * block later to set a correct key
151 * backref type | shared | indirect | shared | indirect
152 * information | tree | tree | data | data
153 * --------------------+--------+----------+--------+----------
154 * parent logical | y | - | - | -
155 * key to resolve | - | y | y | y
156 * tree block logical | - | - | - | -
157 * root for resolving | y | y | y | y
159 * - column 1: we've the parent -> done
160 * - column 2, 3, 4: we use the key to find the parent
162 * on disk refs (inline or keyed)
163 * ==============================
164 * backref type | shared | indirect | shared | indirect
165 * information | tree | tree | data | data
166 * --------------------+--------+----------+--------+----------
167 * parent logical | y | - | y | -
168 * key to resolve | - | - | - | y
169 * tree block logical | y | y | y | y
170 * root for resolving | - | y | y | y
172 * - column 1, 3: we've the parent -> done
173 * - column 2: we take the first key from the block to find the parent
174 * (see __add_missing_keys)
175 * - column 4: we use the key to find the parent
177 * additional information that's available but not required to find the parent
178 * block might help in merging entries to gain some speed.
181 static int __add_prelim_ref(struct list_head
*head
, u64 root_id
,
182 struct btrfs_key
*key
, int level
,
183 u64 parent
, u64 wanted_disk_byte
, int count
,
186 struct __prelim_ref
*ref
;
188 if (root_id
== BTRFS_DATA_RELOC_TREE_OBJECTID
)
191 ref
= kmem_cache_alloc(btrfs_prelim_ref_cache
, gfp_mask
);
195 ref
->root_id
= root_id
;
197 ref
->key_for_search
= *key
;
199 memset(&ref
->key_for_search
, 0, sizeof(ref
->key_for_search
));
201 ref
->inode_list
= NULL
;
204 ref
->parent
= parent
;
205 ref
->wanted_disk_byte
= wanted_disk_byte
;
206 list_add_tail(&ref
->list
, head
);
211 static int add_all_parents(struct btrfs_root
*root
, struct btrfs_path
*path
,
212 struct ulist
*parents
, int level
,
213 struct btrfs_key
*key_for_search
, u64 time_seq
,
214 u64 wanted_disk_byte
,
215 const u64
*extent_item_pos
)
219 struct extent_buffer
*eb
;
220 struct btrfs_key key
;
221 struct btrfs_file_extent_item
*fi
;
222 struct extent_inode_elem
*eie
= NULL
, *old
= NULL
;
226 eb
= path
->nodes
[level
];
227 ret
= ulist_add(parents
, eb
->start
, 0, GFP_NOFS
);
234 * We normally enter this function with the path already pointing to
235 * the first item to check. But sometimes, we may enter it with
236 * slot==nritems. In that case, go to the next leaf before we continue.
238 if (path
->slots
[0] >= btrfs_header_nritems(path
->nodes
[0]))
239 ret
= btrfs_next_old_leaf(root
, path
, time_seq
);
243 slot
= path
->slots
[0];
245 btrfs_item_key_to_cpu(eb
, &key
, slot
);
247 if (key
.objectid
!= key_for_search
->objectid
||
248 key
.type
!= BTRFS_EXTENT_DATA_KEY
)
251 fi
= btrfs_item_ptr(eb
, slot
, struct btrfs_file_extent_item
);
252 disk_byte
= btrfs_file_extent_disk_bytenr(eb
, fi
);
254 if (disk_byte
== wanted_disk_byte
) {
257 if (extent_item_pos
) {
258 ret
= check_extent_in_eb(&key
, eb
, fi
,
266 ret
= ulist_add_merge_ptr(parents
, eb
->start
,
267 eie
, (void **)&old
, GFP_NOFS
);
270 if (!ret
&& extent_item_pos
) {
277 ret
= btrfs_next_old_item(root
, path
, time_seq
);
286 * resolve an indirect backref in the form (root_id, key, level)
287 * to a logical address
289 static int __resolve_indirect_ref(struct btrfs_fs_info
*fs_info
,
290 struct btrfs_path
*path
, u64 time_seq
,
291 struct __prelim_ref
*ref
,
292 struct ulist
*parents
,
293 const u64
*extent_item_pos
)
295 struct btrfs_root
*root
;
296 struct btrfs_key root_key
;
297 struct extent_buffer
*eb
;
300 int level
= ref
->level
;
302 root_key
.objectid
= ref
->root_id
;
303 root_key
.type
= BTRFS_ROOT_ITEM_KEY
;
304 root_key
.offset
= (u64
)-1;
305 root
= btrfs_read_fs_root_no_name(fs_info
, &root_key
);
311 root_level
= btrfs_old_root_level(root
, time_seq
);
313 if (root_level
+ 1 == level
)
316 path
->lowest_level
= level
;
317 ret
= btrfs_search_old_slot(root
, &ref
->key_for_search
, path
, time_seq
);
318 pr_debug("search slot in root %llu (level %d, ref count %d) returned "
319 "%d for key (%llu %u %llu)\n",
320 ref
->root_id
, level
, ref
->count
, ret
,
321 ref
->key_for_search
.objectid
, ref
->key_for_search
.type
,
322 ref
->key_for_search
.offset
);
326 eb
= path
->nodes
[level
];
334 eb
= path
->nodes
[level
];
337 ret
= add_all_parents(root
, path
, parents
, level
, &ref
->key_for_search
,
338 time_seq
, ref
->wanted_disk_byte
,
341 path
->lowest_level
= 0;
342 btrfs_release_path(path
);
347 * resolve all indirect backrefs from the list
349 static int __resolve_indirect_refs(struct btrfs_fs_info
*fs_info
,
350 struct btrfs_path
*path
, u64 time_seq
,
351 struct list_head
*head
,
352 const u64
*extent_item_pos
)
356 struct __prelim_ref
*ref
;
357 struct __prelim_ref
*ref_safe
;
358 struct __prelim_ref
*new_ref
;
359 struct ulist
*parents
;
360 struct ulist_node
*node
;
361 struct ulist_iterator uiter
;
363 parents
= ulist_alloc(GFP_NOFS
);
368 * _safe allows us to insert directly after the current item without
369 * iterating over the newly inserted items.
370 * we're also allowed to re-assign ref during iteration.
372 list_for_each_entry_safe(ref
, ref_safe
, head
, list
) {
373 if (ref
->parent
) /* already direct */
377 err
= __resolve_indirect_ref(fs_info
, path
, time_seq
, ref
,
378 parents
, extent_item_pos
);
384 /* we put the first parent into the ref at hand */
385 ULIST_ITER_INIT(&uiter
);
386 node
= ulist_next(parents
, &uiter
);
387 ref
->parent
= node
? node
->val
: 0;
388 ref
->inode_list
= node
?
389 (struct extent_inode_elem
*)(uintptr_t)node
->aux
: NULL
;
391 /* additional parents require new refs being added here */
392 while ((node
= ulist_next(parents
, &uiter
))) {
393 new_ref
= kmem_cache_alloc(btrfs_prelim_ref_cache
,
399 memcpy(new_ref
, ref
, sizeof(*ref
));
400 new_ref
->parent
= node
->val
;
401 new_ref
->inode_list
= (struct extent_inode_elem
*)
402 (uintptr_t)node
->aux
;
403 list_add(&new_ref
->list
, &ref
->list
);
405 ulist_reinit(parents
);
412 static inline int ref_for_same_block(struct __prelim_ref
*ref1
,
413 struct __prelim_ref
*ref2
)
415 if (ref1
->level
!= ref2
->level
)
417 if (ref1
->root_id
!= ref2
->root_id
)
419 if (ref1
->key_for_search
.type
!= ref2
->key_for_search
.type
)
421 if (ref1
->key_for_search
.objectid
!= ref2
->key_for_search
.objectid
)
423 if (ref1
->key_for_search
.offset
!= ref2
->key_for_search
.offset
)
425 if (ref1
->parent
!= ref2
->parent
)
432 * read tree blocks and add keys where required.
434 static int __add_missing_keys(struct btrfs_fs_info
*fs_info
,
435 struct list_head
*head
)
437 struct list_head
*pos
;
438 struct extent_buffer
*eb
;
440 list_for_each(pos
, head
) {
441 struct __prelim_ref
*ref
;
442 ref
= list_entry(pos
, struct __prelim_ref
, list
);
446 if (ref
->key_for_search
.type
)
448 BUG_ON(!ref
->wanted_disk_byte
);
449 eb
= read_tree_block(fs_info
->tree_root
, ref
->wanted_disk_byte
,
450 fs_info
->tree_root
->leafsize
, 0);
451 if (!eb
|| !extent_buffer_uptodate(eb
)) {
452 free_extent_buffer(eb
);
455 btrfs_tree_read_lock(eb
);
456 if (btrfs_header_level(eb
) == 0)
457 btrfs_item_key_to_cpu(eb
, &ref
->key_for_search
, 0);
459 btrfs_node_key_to_cpu(eb
, &ref
->key_for_search
, 0);
460 btrfs_tree_read_unlock(eb
);
461 free_extent_buffer(eb
);
467 * merge two lists of backrefs and adjust counts accordingly
469 * mode = 1: merge identical keys, if key is set
470 * FIXME: if we add more keys in __add_prelim_ref, we can merge more here.
471 * additionally, we could even add a key range for the blocks we
472 * looked into to merge even more (-> replace unresolved refs by those
474 * mode = 2: merge identical parents
476 static void __merge_refs(struct list_head
*head
, int mode
)
478 struct list_head
*pos1
;
480 list_for_each(pos1
, head
) {
481 struct list_head
*n2
;
482 struct list_head
*pos2
;
483 struct __prelim_ref
*ref1
;
485 ref1
= list_entry(pos1
, struct __prelim_ref
, list
);
487 for (pos2
= pos1
->next
, n2
= pos2
->next
; pos2
!= head
;
488 pos2
= n2
, n2
= pos2
->next
) {
489 struct __prelim_ref
*ref2
;
490 struct __prelim_ref
*xchg
;
491 struct extent_inode_elem
*eie
;
493 ref2
= list_entry(pos2
, struct __prelim_ref
, list
);
496 if (!ref_for_same_block(ref1
, ref2
))
498 if (!ref1
->parent
&& ref2
->parent
) {
504 if (ref1
->parent
!= ref2
->parent
)
508 eie
= ref1
->inode_list
;
509 while (eie
&& eie
->next
)
512 eie
->next
= ref2
->inode_list
;
514 ref1
->inode_list
= ref2
->inode_list
;
515 ref1
->count
+= ref2
->count
;
517 list_del(&ref2
->list
);
518 kmem_cache_free(btrfs_prelim_ref_cache
, ref2
);
525 * add all currently queued delayed refs from this head whose seq nr is
526 * smaller or equal that seq to the list
528 static int __add_delayed_refs(struct btrfs_delayed_ref_head
*head
, u64 seq
,
529 struct list_head
*prefs
)
531 struct btrfs_delayed_extent_op
*extent_op
= head
->extent_op
;
532 struct rb_node
*n
= &head
->node
.rb_node
;
533 struct btrfs_key key
;
534 struct btrfs_key op_key
= {0};
538 if (extent_op
&& extent_op
->update_key
)
539 btrfs_disk_key_to_cpu(&op_key
, &extent_op
->key
);
541 while ((n
= rb_prev(n
))) {
542 struct btrfs_delayed_ref_node
*node
;
543 node
= rb_entry(n
, struct btrfs_delayed_ref_node
,
545 if (node
->bytenr
!= head
->node
.bytenr
)
547 WARN_ON(node
->is_head
);
552 switch (node
->action
) {
553 case BTRFS_ADD_DELAYED_EXTENT
:
554 case BTRFS_UPDATE_DELAYED_HEAD
:
557 case BTRFS_ADD_DELAYED_REF
:
560 case BTRFS_DROP_DELAYED_REF
:
566 switch (node
->type
) {
567 case BTRFS_TREE_BLOCK_REF_KEY
: {
568 struct btrfs_delayed_tree_ref
*ref
;
570 ref
= btrfs_delayed_node_to_tree_ref(node
);
571 ret
= __add_prelim_ref(prefs
, ref
->root
, &op_key
,
572 ref
->level
+ 1, 0, node
->bytenr
,
573 node
->ref_mod
* sgn
, GFP_ATOMIC
);
576 case BTRFS_SHARED_BLOCK_REF_KEY
: {
577 struct btrfs_delayed_tree_ref
*ref
;
579 ref
= btrfs_delayed_node_to_tree_ref(node
);
580 ret
= __add_prelim_ref(prefs
, ref
->root
, NULL
,
581 ref
->level
+ 1, ref
->parent
,
583 node
->ref_mod
* sgn
, GFP_ATOMIC
);
586 case BTRFS_EXTENT_DATA_REF_KEY
: {
587 struct btrfs_delayed_data_ref
*ref
;
588 ref
= btrfs_delayed_node_to_data_ref(node
);
590 key
.objectid
= ref
->objectid
;
591 key
.type
= BTRFS_EXTENT_DATA_KEY
;
592 key
.offset
= ref
->offset
;
593 ret
= __add_prelim_ref(prefs
, ref
->root
, &key
, 0, 0,
595 node
->ref_mod
* sgn
, GFP_ATOMIC
);
598 case BTRFS_SHARED_DATA_REF_KEY
: {
599 struct btrfs_delayed_data_ref
*ref
;
601 ref
= btrfs_delayed_node_to_data_ref(node
);
603 key
.objectid
= ref
->objectid
;
604 key
.type
= BTRFS_EXTENT_DATA_KEY
;
605 key
.offset
= ref
->offset
;
606 ret
= __add_prelim_ref(prefs
, ref
->root
, &key
, 0,
607 ref
->parent
, node
->bytenr
,
608 node
->ref_mod
* sgn
, GFP_ATOMIC
);
622 * add all inline backrefs for bytenr to the list
624 static int __add_inline_refs(struct btrfs_fs_info
*fs_info
,
625 struct btrfs_path
*path
, u64 bytenr
,
626 int *info_level
, struct list_head
*prefs
)
630 struct extent_buffer
*leaf
;
631 struct btrfs_key key
;
632 struct btrfs_key found_key
;
635 struct btrfs_extent_item
*ei
;
640 * enumerate all inline refs
642 leaf
= path
->nodes
[0];
643 slot
= path
->slots
[0];
645 item_size
= btrfs_item_size_nr(leaf
, slot
);
646 BUG_ON(item_size
< sizeof(*ei
));
648 ei
= btrfs_item_ptr(leaf
, slot
, struct btrfs_extent_item
);
649 flags
= btrfs_extent_flags(leaf
, ei
);
650 btrfs_item_key_to_cpu(leaf
, &found_key
, slot
);
652 ptr
= (unsigned long)(ei
+ 1);
653 end
= (unsigned long)ei
+ item_size
;
655 if (found_key
.type
== BTRFS_EXTENT_ITEM_KEY
&&
656 flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
) {
657 struct btrfs_tree_block_info
*info
;
659 info
= (struct btrfs_tree_block_info
*)ptr
;
660 *info_level
= btrfs_tree_block_level(leaf
, info
);
661 ptr
+= sizeof(struct btrfs_tree_block_info
);
663 } else if (found_key
.type
== BTRFS_METADATA_ITEM_KEY
) {
664 *info_level
= found_key
.offset
;
666 BUG_ON(!(flags
& BTRFS_EXTENT_FLAG_DATA
));
670 struct btrfs_extent_inline_ref
*iref
;
674 iref
= (struct btrfs_extent_inline_ref
*)ptr
;
675 type
= btrfs_extent_inline_ref_type(leaf
, iref
);
676 offset
= btrfs_extent_inline_ref_offset(leaf
, iref
);
679 case BTRFS_SHARED_BLOCK_REF_KEY
:
680 ret
= __add_prelim_ref(prefs
, 0, NULL
,
681 *info_level
+ 1, offset
,
682 bytenr
, 1, GFP_NOFS
);
684 case BTRFS_SHARED_DATA_REF_KEY
: {
685 struct btrfs_shared_data_ref
*sdref
;
688 sdref
= (struct btrfs_shared_data_ref
*)(iref
+ 1);
689 count
= btrfs_shared_data_ref_count(leaf
, sdref
);
690 ret
= __add_prelim_ref(prefs
, 0, NULL
, 0, offset
,
691 bytenr
, count
, GFP_NOFS
);
694 case BTRFS_TREE_BLOCK_REF_KEY
:
695 ret
= __add_prelim_ref(prefs
, offset
, NULL
,
697 bytenr
, 1, GFP_NOFS
);
699 case BTRFS_EXTENT_DATA_REF_KEY
: {
700 struct btrfs_extent_data_ref
*dref
;
704 dref
= (struct btrfs_extent_data_ref
*)(&iref
->offset
);
705 count
= btrfs_extent_data_ref_count(leaf
, dref
);
706 key
.objectid
= btrfs_extent_data_ref_objectid(leaf
,
708 key
.type
= BTRFS_EXTENT_DATA_KEY
;
709 key
.offset
= btrfs_extent_data_ref_offset(leaf
, dref
);
710 root
= btrfs_extent_data_ref_root(leaf
, dref
);
711 ret
= __add_prelim_ref(prefs
, root
, &key
, 0, 0,
712 bytenr
, count
, GFP_NOFS
);
720 ptr
+= btrfs_extent_inline_ref_size(type
);
727 * add all non-inline backrefs for bytenr to the list
729 static int __add_keyed_refs(struct btrfs_fs_info
*fs_info
,
730 struct btrfs_path
*path
, u64 bytenr
,
731 int info_level
, struct list_head
*prefs
)
733 struct btrfs_root
*extent_root
= fs_info
->extent_root
;
736 struct extent_buffer
*leaf
;
737 struct btrfs_key key
;
740 ret
= btrfs_next_item(extent_root
, path
);
748 slot
= path
->slots
[0];
749 leaf
= path
->nodes
[0];
750 btrfs_item_key_to_cpu(leaf
, &key
, slot
);
752 if (key
.objectid
!= bytenr
)
754 if (key
.type
< BTRFS_TREE_BLOCK_REF_KEY
)
756 if (key
.type
> BTRFS_SHARED_DATA_REF_KEY
)
760 case BTRFS_SHARED_BLOCK_REF_KEY
:
761 ret
= __add_prelim_ref(prefs
, 0, NULL
,
762 info_level
+ 1, key
.offset
,
763 bytenr
, 1, GFP_NOFS
);
765 case BTRFS_SHARED_DATA_REF_KEY
: {
766 struct btrfs_shared_data_ref
*sdref
;
769 sdref
= btrfs_item_ptr(leaf
, slot
,
770 struct btrfs_shared_data_ref
);
771 count
= btrfs_shared_data_ref_count(leaf
, sdref
);
772 ret
= __add_prelim_ref(prefs
, 0, NULL
, 0, key
.offset
,
773 bytenr
, count
, GFP_NOFS
);
776 case BTRFS_TREE_BLOCK_REF_KEY
:
777 ret
= __add_prelim_ref(prefs
, key
.offset
, NULL
,
779 bytenr
, 1, GFP_NOFS
);
781 case BTRFS_EXTENT_DATA_REF_KEY
: {
782 struct btrfs_extent_data_ref
*dref
;
786 dref
= btrfs_item_ptr(leaf
, slot
,
787 struct btrfs_extent_data_ref
);
788 count
= btrfs_extent_data_ref_count(leaf
, dref
);
789 key
.objectid
= btrfs_extent_data_ref_objectid(leaf
,
791 key
.type
= BTRFS_EXTENT_DATA_KEY
;
792 key
.offset
= btrfs_extent_data_ref_offset(leaf
, dref
);
793 root
= btrfs_extent_data_ref_root(leaf
, dref
);
794 ret
= __add_prelim_ref(prefs
, root
, &key
, 0, 0,
795 bytenr
, count
, GFP_NOFS
);
810 * this adds all existing backrefs (inline backrefs, backrefs and delayed
811 * refs) for the given bytenr to the refs list, merges duplicates and resolves
812 * indirect refs to their parent bytenr.
813 * When roots are found, they're added to the roots list
815 * FIXME some caching might speed things up
817 static int find_parent_nodes(struct btrfs_trans_handle
*trans
,
818 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
819 u64 time_seq
, struct ulist
*refs
,
820 struct ulist
*roots
, const u64
*extent_item_pos
)
822 struct btrfs_key key
;
823 struct btrfs_path
*path
;
824 struct btrfs_delayed_ref_root
*delayed_refs
= NULL
;
825 struct btrfs_delayed_ref_head
*head
;
828 struct list_head prefs_delayed
;
829 struct list_head prefs
;
830 struct __prelim_ref
*ref
;
832 INIT_LIST_HEAD(&prefs
);
833 INIT_LIST_HEAD(&prefs_delayed
);
835 key
.objectid
= bytenr
;
836 key
.offset
= (u64
)-1;
837 if (btrfs_fs_incompat(fs_info
, SKINNY_METADATA
))
838 key
.type
= BTRFS_METADATA_ITEM_KEY
;
840 key
.type
= BTRFS_EXTENT_ITEM_KEY
;
842 path
= btrfs_alloc_path();
846 path
->search_commit_root
= 1;
849 * grab both a lock on the path and a lock on the delayed ref head.
850 * We need both to get a consistent picture of how the refs look
851 * at a specified point in time
856 ret
= btrfs_search_slot(trans
, fs_info
->extent_root
, &key
, path
, 0, 0);
863 * look if there are updates for this ref queued and lock the
866 delayed_refs
= &trans
->transaction
->delayed_refs
;
867 spin_lock(&delayed_refs
->lock
);
868 head
= btrfs_find_delayed_ref_head(trans
, bytenr
);
870 if (!mutex_trylock(&head
->mutex
)) {
871 atomic_inc(&head
->node
.refs
);
872 spin_unlock(&delayed_refs
->lock
);
874 btrfs_release_path(path
);
877 * Mutex was contended, block until it's
878 * released and try again
880 mutex_lock(&head
->mutex
);
881 mutex_unlock(&head
->mutex
);
882 btrfs_put_delayed_ref(&head
->node
);
885 ret
= __add_delayed_refs(head
, time_seq
,
887 mutex_unlock(&head
->mutex
);
889 spin_unlock(&delayed_refs
->lock
);
893 spin_unlock(&delayed_refs
->lock
);
896 if (path
->slots
[0]) {
897 struct extent_buffer
*leaf
;
901 leaf
= path
->nodes
[0];
902 slot
= path
->slots
[0];
903 btrfs_item_key_to_cpu(leaf
, &key
, slot
);
904 if (key
.objectid
== bytenr
&&
905 (key
.type
== BTRFS_EXTENT_ITEM_KEY
||
906 key
.type
== BTRFS_METADATA_ITEM_KEY
)) {
907 ret
= __add_inline_refs(fs_info
, path
, bytenr
,
908 &info_level
, &prefs
);
911 ret
= __add_keyed_refs(fs_info
, path
, bytenr
,
917 btrfs_release_path(path
);
919 list_splice_init(&prefs_delayed
, &prefs
);
921 ret
= __add_missing_keys(fs_info
, &prefs
);
925 __merge_refs(&prefs
, 1);
927 ret
= __resolve_indirect_refs(fs_info
, path
, time_seq
, &prefs
,
932 __merge_refs(&prefs
, 2);
934 while (!list_empty(&prefs
)) {
935 ref
= list_first_entry(&prefs
, struct __prelim_ref
, list
);
936 WARN_ON(ref
->count
< 0);
937 if (ref
->count
&& ref
->root_id
&& ref
->parent
== 0) {
938 /* no parent == root of tree */
939 ret
= ulist_add(roots
, ref
->root_id
, 0, GFP_NOFS
);
943 if (ref
->count
&& ref
->parent
) {
944 struct extent_inode_elem
*eie
= NULL
;
945 if (extent_item_pos
&& !ref
->inode_list
) {
947 struct extent_buffer
*eb
;
948 bsz
= btrfs_level_size(fs_info
->extent_root
,
950 eb
= read_tree_block(fs_info
->extent_root
,
951 ref
->parent
, bsz
, 0);
952 if (!eb
|| !extent_buffer_uptodate(eb
)) {
953 free_extent_buffer(eb
);
957 btrfs_tree_read_lock(eb
);
958 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
959 ret
= find_extent_in_eb(eb
, bytenr
,
960 *extent_item_pos
, &eie
);
961 btrfs_tree_read_unlock_blocking(eb
);
962 free_extent_buffer(eb
);
965 ref
->inode_list
= eie
;
967 ret
= ulist_add_merge_ptr(refs
, ref
->parent
,
969 (void **)&eie
, GFP_NOFS
);
972 if (!ret
&& extent_item_pos
) {
974 * we've recorded that parent, so we must extend
975 * its inode list here
980 eie
->next
= ref
->inode_list
;
983 list_del(&ref
->list
);
984 kmem_cache_free(btrfs_prelim_ref_cache
, ref
);
988 btrfs_free_path(path
);
989 while (!list_empty(&prefs
)) {
990 ref
= list_first_entry(&prefs
, struct __prelim_ref
, list
);
991 list_del(&ref
->list
);
992 kmem_cache_free(btrfs_prelim_ref_cache
, ref
);
994 while (!list_empty(&prefs_delayed
)) {
995 ref
= list_first_entry(&prefs_delayed
, struct __prelim_ref
,
997 list_del(&ref
->list
);
998 kmem_cache_free(btrfs_prelim_ref_cache
, ref
);
1004 static void free_leaf_list(struct ulist
*blocks
)
1006 struct ulist_node
*node
= NULL
;
1007 struct extent_inode_elem
*eie
;
1008 struct extent_inode_elem
*eie_next
;
1009 struct ulist_iterator uiter
;
1011 ULIST_ITER_INIT(&uiter
);
1012 while ((node
= ulist_next(blocks
, &uiter
))) {
1015 eie
= (struct extent_inode_elem
*)(uintptr_t)node
->aux
;
1016 for (; eie
; eie
= eie_next
) {
1017 eie_next
= eie
->next
;
1027 * Finds all leafs with a reference to the specified combination of bytenr and
1028 * offset. key_list_head will point to a list of corresponding keys (caller must
1029 * free each list element). The leafs will be stored in the leafs ulist, which
1030 * must be freed with ulist_free.
1032 * returns 0 on success, <0 on error
1034 static int btrfs_find_all_leafs(struct btrfs_trans_handle
*trans
,
1035 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
1036 u64 time_seq
, struct ulist
**leafs
,
1037 const u64
*extent_item_pos
)
1042 tmp
= ulist_alloc(GFP_NOFS
);
1045 *leafs
= ulist_alloc(GFP_NOFS
);
1051 ret
= find_parent_nodes(trans
, fs_info
, bytenr
,
1052 time_seq
, *leafs
, tmp
, extent_item_pos
);
1055 if (ret
< 0 && ret
!= -ENOENT
) {
1056 free_leaf_list(*leafs
);
1064 * walk all backrefs for a given extent to find all roots that reference this
1065 * extent. Walking a backref means finding all extents that reference this
1066 * extent and in turn walk the backrefs of those, too. Naturally this is a
1067 * recursive process, but here it is implemented in an iterative fashion: We
1068 * find all referencing extents for the extent in question and put them on a
1069 * list. In turn, we find all referencing extents for those, further appending
1070 * to the list. The way we iterate the list allows adding more elements after
1071 * the current while iterating. The process stops when we reach the end of the
1072 * list. Found roots are added to the roots list.
1074 * returns 0 on success, < 0 on error.
1076 int btrfs_find_all_roots(struct btrfs_trans_handle
*trans
,
1077 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
1078 u64 time_seq
, struct ulist
**roots
)
1081 struct ulist_node
*node
= NULL
;
1082 struct ulist_iterator uiter
;
1085 tmp
= ulist_alloc(GFP_NOFS
);
1088 *roots
= ulist_alloc(GFP_NOFS
);
1094 ULIST_ITER_INIT(&uiter
);
1096 ret
= find_parent_nodes(trans
, fs_info
, bytenr
,
1097 time_seq
, tmp
, *roots
, NULL
);
1098 if (ret
< 0 && ret
!= -ENOENT
) {
1103 node
= ulist_next(tmp
, &uiter
);
1114 static int __inode_info(u64 inum
, u64 ioff
, u8 key_type
,
1115 struct btrfs_root
*fs_root
, struct btrfs_path
*path
,
1116 struct btrfs_key
*found_key
)
1119 struct btrfs_key key
;
1120 struct extent_buffer
*eb
;
1122 key
.type
= key_type
;
1123 key
.objectid
= inum
;
1126 ret
= btrfs_search_slot(NULL
, fs_root
, &key
, path
, 0, 0);
1130 eb
= path
->nodes
[0];
1131 if (ret
&& path
->slots
[0] >= btrfs_header_nritems(eb
)) {
1132 ret
= btrfs_next_leaf(fs_root
, path
);
1135 eb
= path
->nodes
[0];
1138 btrfs_item_key_to_cpu(eb
, found_key
, path
->slots
[0]);
1139 if (found_key
->type
!= key
.type
|| found_key
->objectid
!= key
.objectid
)
1146 * this makes the path point to (inum INODE_ITEM ioff)
1148 int inode_item_info(u64 inum
, u64 ioff
, struct btrfs_root
*fs_root
,
1149 struct btrfs_path
*path
)
1151 struct btrfs_key key
;
1152 return __inode_info(inum
, ioff
, BTRFS_INODE_ITEM_KEY
, fs_root
, path
,
1156 static int inode_ref_info(u64 inum
, u64 ioff
, struct btrfs_root
*fs_root
,
1157 struct btrfs_path
*path
,
1158 struct btrfs_key
*found_key
)
1160 return __inode_info(inum
, ioff
, BTRFS_INODE_REF_KEY
, fs_root
, path
,
1164 int btrfs_find_one_extref(struct btrfs_root
*root
, u64 inode_objectid
,
1165 u64 start_off
, struct btrfs_path
*path
,
1166 struct btrfs_inode_extref
**ret_extref
,
1170 struct btrfs_key key
;
1171 struct btrfs_key found_key
;
1172 struct btrfs_inode_extref
*extref
;
1173 struct extent_buffer
*leaf
;
1176 key
.objectid
= inode_objectid
;
1177 btrfs_set_key_type(&key
, BTRFS_INODE_EXTREF_KEY
);
1178 key
.offset
= start_off
;
1180 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
1185 leaf
= path
->nodes
[0];
1186 slot
= path
->slots
[0];
1187 if (slot
>= btrfs_header_nritems(leaf
)) {
1189 * If the item at offset is not found,
1190 * btrfs_search_slot will point us to the slot
1191 * where it should be inserted. In our case
1192 * that will be the slot directly before the
1193 * next INODE_REF_KEY_V2 item. In the case
1194 * that we're pointing to the last slot in a
1195 * leaf, we must move one leaf over.
1197 ret
= btrfs_next_leaf(root
, path
);
1206 btrfs_item_key_to_cpu(leaf
, &found_key
, slot
);
1209 * Check that we're still looking at an extended ref key for
1210 * this particular objectid. If we have different
1211 * objectid or type then there are no more to be found
1212 * in the tree and we can exit.
1215 if (found_key
.objectid
!= inode_objectid
)
1217 if (btrfs_key_type(&found_key
) != BTRFS_INODE_EXTREF_KEY
)
1221 ptr
= btrfs_item_ptr_offset(leaf
, path
->slots
[0]);
1222 extref
= (struct btrfs_inode_extref
*)ptr
;
1223 *ret_extref
= extref
;
1225 *found_off
= found_key
.offset
;
1233 * this iterates to turn a name (from iref/extref) into a full filesystem path.
1234 * Elements of the path are separated by '/' and the path is guaranteed to be
1235 * 0-terminated. the path is only given within the current file system.
1236 * Therefore, it never starts with a '/'. the caller is responsible to provide
1237 * "size" bytes in "dest". the dest buffer will be filled backwards. finally,
1238 * the start point of the resulting string is returned. this pointer is within
1240 * in case the path buffer would overflow, the pointer is decremented further
1241 * as if output was written to the buffer, though no more output is actually
1242 * generated. that way, the caller can determine how much space would be
1243 * required for the path to fit into the buffer. in that case, the returned
1244 * value will be smaller than dest. callers must check this!
1246 char *btrfs_ref_to_path(struct btrfs_root
*fs_root
, struct btrfs_path
*path
,
1247 u32 name_len
, unsigned long name_off
,
1248 struct extent_buffer
*eb_in
, u64 parent
,
1249 char *dest
, u32 size
)
1254 s64 bytes_left
= ((s64
)size
) - 1;
1255 struct extent_buffer
*eb
= eb_in
;
1256 struct btrfs_key found_key
;
1257 int leave_spinning
= path
->leave_spinning
;
1258 struct btrfs_inode_ref
*iref
;
1260 if (bytes_left
>= 0)
1261 dest
[bytes_left
] = '\0';
1263 path
->leave_spinning
= 1;
1265 bytes_left
-= name_len
;
1266 if (bytes_left
>= 0)
1267 read_extent_buffer(eb
, dest
+ bytes_left
,
1268 name_off
, name_len
);
1270 btrfs_tree_read_unlock_blocking(eb
);
1271 free_extent_buffer(eb
);
1273 ret
= inode_ref_info(parent
, 0, fs_root
, path
, &found_key
);
1279 next_inum
= found_key
.offset
;
1281 /* regular exit ahead */
1282 if (parent
== next_inum
)
1285 slot
= path
->slots
[0];
1286 eb
= path
->nodes
[0];
1287 /* make sure we can use eb after releasing the path */
1289 atomic_inc(&eb
->refs
);
1290 btrfs_tree_read_lock(eb
);
1291 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1293 btrfs_release_path(path
);
1294 iref
= btrfs_item_ptr(eb
, slot
, struct btrfs_inode_ref
);
1296 name_len
= btrfs_inode_ref_name_len(eb
, iref
);
1297 name_off
= (unsigned long)(iref
+ 1);
1301 if (bytes_left
>= 0)
1302 dest
[bytes_left
] = '/';
1305 btrfs_release_path(path
);
1306 path
->leave_spinning
= leave_spinning
;
1309 return ERR_PTR(ret
);
1311 return dest
+ bytes_left
;
1315 * this makes the path point to (logical EXTENT_ITEM *)
1316 * returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for
1317 * tree blocks and <0 on error.
1319 int extent_from_logical(struct btrfs_fs_info
*fs_info
, u64 logical
,
1320 struct btrfs_path
*path
, struct btrfs_key
*found_key
,
1327 struct extent_buffer
*eb
;
1328 struct btrfs_extent_item
*ei
;
1329 struct btrfs_key key
;
1331 if (btrfs_fs_incompat(fs_info
, SKINNY_METADATA
))
1332 key
.type
= BTRFS_METADATA_ITEM_KEY
;
1334 key
.type
= BTRFS_EXTENT_ITEM_KEY
;
1335 key
.objectid
= logical
;
1336 key
.offset
= (u64
)-1;
1338 ret
= btrfs_search_slot(NULL
, fs_info
->extent_root
, &key
, path
, 0, 0);
1341 ret
= btrfs_previous_item(fs_info
->extent_root
, path
,
1342 0, BTRFS_EXTENT_ITEM_KEY
);
1346 btrfs_item_key_to_cpu(path
->nodes
[0], found_key
, path
->slots
[0]);
1347 if (found_key
->type
== BTRFS_METADATA_ITEM_KEY
)
1348 size
= fs_info
->extent_root
->leafsize
;
1349 else if (found_key
->type
== BTRFS_EXTENT_ITEM_KEY
)
1350 size
= found_key
->offset
;
1352 if ((found_key
->type
!= BTRFS_EXTENT_ITEM_KEY
&&
1353 found_key
->type
!= BTRFS_METADATA_ITEM_KEY
) ||
1354 found_key
->objectid
> logical
||
1355 found_key
->objectid
+ size
<= logical
) {
1356 pr_debug("logical %llu is not within any extent\n", logical
);
1360 eb
= path
->nodes
[0];
1361 item_size
= btrfs_item_size_nr(eb
, path
->slots
[0]);
1362 BUG_ON(item_size
< sizeof(*ei
));
1364 ei
= btrfs_item_ptr(eb
, path
->slots
[0], struct btrfs_extent_item
);
1365 flags
= btrfs_extent_flags(eb
, ei
);
1367 pr_debug("logical %llu is at position %llu within the extent (%llu "
1368 "EXTENT_ITEM %llu) flags %#llx size %u\n",
1369 logical
, logical
- found_key
->objectid
, found_key
->objectid
,
1370 found_key
->offset
, flags
, item_size
);
1372 WARN_ON(!flags_ret
);
1374 if (flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
)
1375 *flags_ret
= BTRFS_EXTENT_FLAG_TREE_BLOCK
;
1376 else if (flags
& BTRFS_EXTENT_FLAG_DATA
)
1377 *flags_ret
= BTRFS_EXTENT_FLAG_DATA
;
1387 * helper function to iterate extent inline refs. ptr must point to a 0 value
1388 * for the first call and may be modified. it is used to track state.
1389 * if more refs exist, 0 is returned and the next call to
1390 * __get_extent_inline_ref must pass the modified ptr parameter to get the
1391 * next ref. after the last ref was processed, 1 is returned.
1392 * returns <0 on error
1394 static int __get_extent_inline_ref(unsigned long *ptr
, struct extent_buffer
*eb
,
1395 struct btrfs_key
*key
,
1396 struct btrfs_extent_item
*ei
, u32 item_size
,
1397 struct btrfs_extent_inline_ref
**out_eiref
,
1402 struct btrfs_tree_block_info
*info
;
1406 flags
= btrfs_extent_flags(eb
, ei
);
1407 if (flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
) {
1408 if (key
->type
== BTRFS_METADATA_ITEM_KEY
) {
1409 /* a skinny metadata extent */
1411 (struct btrfs_extent_inline_ref
*)(ei
+ 1);
1413 WARN_ON(key
->type
!= BTRFS_EXTENT_ITEM_KEY
);
1414 info
= (struct btrfs_tree_block_info
*)(ei
+ 1);
1416 (struct btrfs_extent_inline_ref
*)(info
+ 1);
1419 *out_eiref
= (struct btrfs_extent_inline_ref
*)(ei
+ 1);
1421 *ptr
= (unsigned long)*out_eiref
;
1422 if ((unsigned long)(*ptr
) >= (unsigned long)ei
+ item_size
)
1426 end
= (unsigned long)ei
+ item_size
;
1427 *out_eiref
= (struct btrfs_extent_inline_ref
*)(*ptr
);
1428 *out_type
= btrfs_extent_inline_ref_type(eb
, *out_eiref
);
1430 *ptr
+= btrfs_extent_inline_ref_size(*out_type
);
1431 WARN_ON(*ptr
> end
);
1433 return 1; /* last */
1439 * reads the tree block backref for an extent. tree level and root are returned
1440 * through out_level and out_root. ptr must point to a 0 value for the first
1441 * call and may be modified (see __get_extent_inline_ref comment).
1442 * returns 0 if data was provided, 1 if there was no more data to provide or
1445 int tree_backref_for_extent(unsigned long *ptr
, struct extent_buffer
*eb
,
1446 struct btrfs_key
*key
, struct btrfs_extent_item
*ei
,
1447 u32 item_size
, u64
*out_root
, u8
*out_level
)
1451 struct btrfs_tree_block_info
*info
;
1452 struct btrfs_extent_inline_ref
*eiref
;
1454 if (*ptr
== (unsigned long)-1)
1458 ret
= __get_extent_inline_ref(ptr
, eb
, key
, ei
, item_size
,
1463 if (type
== BTRFS_TREE_BLOCK_REF_KEY
||
1464 type
== BTRFS_SHARED_BLOCK_REF_KEY
)
1471 /* we can treat both ref types equally here */
1472 info
= (struct btrfs_tree_block_info
*)(ei
+ 1);
1473 *out_root
= btrfs_extent_inline_ref_offset(eb
, eiref
);
1474 *out_level
= btrfs_tree_block_level(eb
, info
);
1477 *ptr
= (unsigned long)-1;
1482 static int iterate_leaf_refs(struct extent_inode_elem
*inode_list
,
1483 u64 root
, u64 extent_item_objectid
,
1484 iterate_extent_inodes_t
*iterate
, void *ctx
)
1486 struct extent_inode_elem
*eie
;
1489 for (eie
= inode_list
; eie
; eie
= eie
->next
) {
1490 pr_debug("ref for %llu resolved, key (%llu EXTEND_DATA %llu), "
1491 "root %llu\n", extent_item_objectid
,
1492 eie
->inum
, eie
->offset
, root
);
1493 ret
= iterate(eie
->inum
, eie
->offset
, root
, ctx
);
1495 pr_debug("stopping iteration for %llu due to ret=%d\n",
1496 extent_item_objectid
, ret
);
1505 * calls iterate() for every inode that references the extent identified by
1506 * the given parameters.
1507 * when the iterator function returns a non-zero value, iteration stops.
1509 int iterate_extent_inodes(struct btrfs_fs_info
*fs_info
,
1510 u64 extent_item_objectid
, u64 extent_item_pos
,
1511 int search_commit_root
,
1512 iterate_extent_inodes_t
*iterate
, void *ctx
)
1515 struct btrfs_trans_handle
*trans
= NULL
;
1516 struct ulist
*refs
= NULL
;
1517 struct ulist
*roots
= NULL
;
1518 struct ulist_node
*ref_node
= NULL
;
1519 struct ulist_node
*root_node
= NULL
;
1520 struct seq_list tree_mod_seq_elem
= {};
1521 struct ulist_iterator ref_uiter
;
1522 struct ulist_iterator root_uiter
;
1524 pr_debug("resolving all inodes for extent %llu\n",
1525 extent_item_objectid
);
1527 if (!search_commit_root
) {
1528 trans
= btrfs_join_transaction(fs_info
->extent_root
);
1530 return PTR_ERR(trans
);
1531 btrfs_get_tree_mod_seq(fs_info
, &tree_mod_seq_elem
);
1534 ret
= btrfs_find_all_leafs(trans
, fs_info
, extent_item_objectid
,
1535 tree_mod_seq_elem
.seq
, &refs
,
1540 ULIST_ITER_INIT(&ref_uiter
);
1541 while (!ret
&& (ref_node
= ulist_next(refs
, &ref_uiter
))) {
1542 ret
= btrfs_find_all_roots(trans
, fs_info
, ref_node
->val
,
1543 tree_mod_seq_elem
.seq
, &roots
);
1546 ULIST_ITER_INIT(&root_uiter
);
1547 while (!ret
&& (root_node
= ulist_next(roots
, &root_uiter
))) {
1548 pr_debug("root %llu references leaf %llu, data list "
1549 "%#llx\n", root_node
->val
, ref_node
->val
,
1551 ret
= iterate_leaf_refs((struct extent_inode_elem
*)
1552 (uintptr_t)ref_node
->aux
,
1554 extent_item_objectid
,
1560 free_leaf_list(refs
);
1562 if (!search_commit_root
) {
1563 btrfs_put_tree_mod_seq(fs_info
, &tree_mod_seq_elem
);
1564 btrfs_end_transaction(trans
, fs_info
->extent_root
);
1570 int iterate_inodes_from_logical(u64 logical
, struct btrfs_fs_info
*fs_info
,
1571 struct btrfs_path
*path
,
1572 iterate_extent_inodes_t
*iterate
, void *ctx
)
1575 u64 extent_item_pos
;
1577 struct btrfs_key found_key
;
1578 int search_commit_root
= path
->search_commit_root
;
1580 ret
= extent_from_logical(fs_info
, logical
, path
, &found_key
, &flags
);
1581 btrfs_release_path(path
);
1584 if (flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
)
1587 extent_item_pos
= logical
- found_key
.objectid
;
1588 ret
= iterate_extent_inodes(fs_info
, found_key
.objectid
,
1589 extent_item_pos
, search_commit_root
,
1595 typedef int (iterate_irefs_t
)(u64 parent
, u32 name_len
, unsigned long name_off
,
1596 struct extent_buffer
*eb
, void *ctx
);
1598 static int iterate_inode_refs(u64 inum
, struct btrfs_root
*fs_root
,
1599 struct btrfs_path
*path
,
1600 iterate_irefs_t
*iterate
, void *ctx
)
1609 struct extent_buffer
*eb
;
1610 struct btrfs_item
*item
;
1611 struct btrfs_inode_ref
*iref
;
1612 struct btrfs_key found_key
;
1615 path
->leave_spinning
= 1;
1616 ret
= inode_ref_info(inum
, parent
? parent
+1 : 0, fs_root
, path
,
1621 ret
= found
? 0 : -ENOENT
;
1626 parent
= found_key
.offset
;
1627 slot
= path
->slots
[0];
1628 eb
= path
->nodes
[0];
1629 /* make sure we can use eb after releasing the path */
1630 atomic_inc(&eb
->refs
);
1631 btrfs_tree_read_lock(eb
);
1632 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1633 btrfs_release_path(path
);
1635 item
= btrfs_item_nr(eb
, slot
);
1636 iref
= btrfs_item_ptr(eb
, slot
, struct btrfs_inode_ref
);
1638 for (cur
= 0; cur
< btrfs_item_size(eb
, item
); cur
+= len
) {
1639 name_len
= btrfs_inode_ref_name_len(eb
, iref
);
1640 /* path must be released before calling iterate()! */
1641 pr_debug("following ref at offset %u for inode %llu in "
1642 "tree %llu\n", cur
, found_key
.objectid
,
1644 ret
= iterate(parent
, name_len
,
1645 (unsigned long)(iref
+ 1), eb
, ctx
);
1648 len
= sizeof(*iref
) + name_len
;
1649 iref
= (struct btrfs_inode_ref
*)((char *)iref
+ len
);
1651 btrfs_tree_read_unlock_blocking(eb
);
1652 free_extent_buffer(eb
);
1655 btrfs_release_path(path
);
1660 static int iterate_inode_extrefs(u64 inum
, struct btrfs_root
*fs_root
,
1661 struct btrfs_path
*path
,
1662 iterate_irefs_t
*iterate
, void *ctx
)
1669 struct extent_buffer
*eb
;
1670 struct btrfs_inode_extref
*extref
;
1671 struct extent_buffer
*leaf
;
1677 ret
= btrfs_find_one_extref(fs_root
, inum
, offset
, path
, &extref
,
1682 ret
= found
? 0 : -ENOENT
;
1687 slot
= path
->slots
[0];
1688 eb
= path
->nodes
[0];
1689 /* make sure we can use eb after releasing the path */
1690 atomic_inc(&eb
->refs
);
1692 btrfs_tree_read_lock(eb
);
1693 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1694 btrfs_release_path(path
);
1696 leaf
= path
->nodes
[0];
1697 item_size
= btrfs_item_size_nr(leaf
, path
->slots
[0]);
1698 ptr
= btrfs_item_ptr_offset(leaf
, path
->slots
[0]);
1701 while (cur_offset
< item_size
) {
1704 extref
= (struct btrfs_inode_extref
*)(ptr
+ cur_offset
);
1705 parent
= btrfs_inode_extref_parent(eb
, extref
);
1706 name_len
= btrfs_inode_extref_name_len(eb
, extref
);
1707 ret
= iterate(parent
, name_len
,
1708 (unsigned long)&extref
->name
, eb
, ctx
);
1712 cur_offset
+= btrfs_inode_extref_name_len(leaf
, extref
);
1713 cur_offset
+= sizeof(*extref
);
1715 btrfs_tree_read_unlock_blocking(eb
);
1716 free_extent_buffer(eb
);
1721 btrfs_release_path(path
);
1726 static int iterate_irefs(u64 inum
, struct btrfs_root
*fs_root
,
1727 struct btrfs_path
*path
, iterate_irefs_t
*iterate
,
1733 ret
= iterate_inode_refs(inum
, fs_root
, path
, iterate
, ctx
);
1736 else if (ret
!= -ENOENT
)
1739 ret
= iterate_inode_extrefs(inum
, fs_root
, path
, iterate
, ctx
);
1740 if (ret
== -ENOENT
&& found_refs
)
1747 * returns 0 if the path could be dumped (probably truncated)
1748 * returns <0 in case of an error
1750 static int inode_to_path(u64 inum
, u32 name_len
, unsigned long name_off
,
1751 struct extent_buffer
*eb
, void *ctx
)
1753 struct inode_fs_paths
*ipath
= ctx
;
1756 int i
= ipath
->fspath
->elem_cnt
;
1757 const int s_ptr
= sizeof(char *);
1760 bytes_left
= ipath
->fspath
->bytes_left
> s_ptr
?
1761 ipath
->fspath
->bytes_left
- s_ptr
: 0;
1763 fspath_min
= (char *)ipath
->fspath
->val
+ (i
+ 1) * s_ptr
;
1764 fspath
= btrfs_ref_to_path(ipath
->fs_root
, ipath
->btrfs_path
, name_len
,
1765 name_off
, eb
, inum
, fspath_min
, bytes_left
);
1767 return PTR_ERR(fspath
);
1769 if (fspath
> fspath_min
) {
1770 ipath
->fspath
->val
[i
] = (u64
)(unsigned long)fspath
;
1771 ++ipath
->fspath
->elem_cnt
;
1772 ipath
->fspath
->bytes_left
= fspath
- fspath_min
;
1774 ++ipath
->fspath
->elem_missed
;
1775 ipath
->fspath
->bytes_missing
+= fspath_min
- fspath
;
1776 ipath
->fspath
->bytes_left
= 0;
1783 * this dumps all file system paths to the inode into the ipath struct, provided
1784 * is has been created large enough. each path is zero-terminated and accessed
1785 * from ipath->fspath->val[i].
1786 * when it returns, there are ipath->fspath->elem_cnt number of paths available
1787 * in ipath->fspath->val[]. when the allocated space wasn't sufficient, the
1788 * number of missed paths in recored in ipath->fspath->elem_missed, otherwise,
1789 * it's zero. ipath->fspath->bytes_missing holds the number of bytes that would
1790 * have been needed to return all paths.
1792 int paths_from_inode(u64 inum
, struct inode_fs_paths
*ipath
)
1794 return iterate_irefs(inum
, ipath
->fs_root
, ipath
->btrfs_path
,
1795 inode_to_path
, ipath
);
1798 struct btrfs_data_container
*init_data_container(u32 total_bytes
)
1800 struct btrfs_data_container
*data
;
1803 alloc_bytes
= max_t(size_t, total_bytes
, sizeof(*data
));
1804 data
= vmalloc(alloc_bytes
);
1806 return ERR_PTR(-ENOMEM
);
1808 if (total_bytes
>= sizeof(*data
)) {
1809 data
->bytes_left
= total_bytes
- sizeof(*data
);
1810 data
->bytes_missing
= 0;
1812 data
->bytes_missing
= sizeof(*data
) - total_bytes
;
1813 data
->bytes_left
= 0;
1817 data
->elem_missed
= 0;
1823 * allocates space to return multiple file system paths for an inode.
1824 * total_bytes to allocate are passed, note that space usable for actual path
1825 * information will be total_bytes - sizeof(struct inode_fs_paths).
1826 * the returned pointer must be freed with free_ipath() in the end.
1828 struct inode_fs_paths
*init_ipath(s32 total_bytes
, struct btrfs_root
*fs_root
,
1829 struct btrfs_path
*path
)
1831 struct inode_fs_paths
*ifp
;
1832 struct btrfs_data_container
*fspath
;
1834 fspath
= init_data_container(total_bytes
);
1836 return (void *)fspath
;
1838 ifp
= kmalloc(sizeof(*ifp
), GFP_NOFS
);
1841 return ERR_PTR(-ENOMEM
);
1844 ifp
->btrfs_path
= path
;
1845 ifp
->fspath
= fspath
;
1846 ifp
->fs_root
= fs_root
;
1851 void free_ipath(struct inode_fs_paths
*ipath
)
1855 vfree(ipath
->fspath
);