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(parents
, eb
->start
,
281 (u64
*)&old
, GFP_NOFS
);
284 if (!ret
&& extent_item_pos
) {
292 ret
= btrfs_next_old_item(root
, path
, time_seq
);
298 free_inode_elem_list(eie
);
303 * resolve an indirect backref in the form (root_id, key, level)
304 * to a logical address
306 static int __resolve_indirect_ref(struct btrfs_fs_info
*fs_info
,
307 struct btrfs_path
*path
, u64 time_seq
,
308 struct __prelim_ref
*ref
,
309 struct ulist
*parents
,
310 const u64
*extent_item_pos
, u64 total_refs
)
312 struct btrfs_root
*root
;
313 struct btrfs_key root_key
;
314 struct extent_buffer
*eb
;
317 int level
= ref
->level
;
320 root_key
.objectid
= ref
->root_id
;
321 root_key
.type
= BTRFS_ROOT_ITEM_KEY
;
322 root_key
.offset
= (u64
)-1;
324 index
= srcu_read_lock(&fs_info
->subvol_srcu
);
326 root
= btrfs_read_fs_root_no_name(fs_info
, &root_key
);
328 srcu_read_unlock(&fs_info
->subvol_srcu
, index
);
333 root_level
= btrfs_old_root_level(root
, time_seq
);
335 if (root_level
+ 1 == level
) {
336 srcu_read_unlock(&fs_info
->subvol_srcu
, index
);
340 path
->lowest_level
= level
;
341 ret
= btrfs_search_old_slot(root
, &ref
->key_for_search
, path
, time_seq
);
343 /* root node has been locked, we can release @subvol_srcu safely here */
344 srcu_read_unlock(&fs_info
->subvol_srcu
, index
);
346 pr_debug("search slot in root %llu (level %d, ref count %d) returned "
347 "%d for key (%llu %u %llu)\n",
348 ref
->root_id
, level
, ref
->count
, ret
,
349 ref
->key_for_search
.objectid
, ref
->key_for_search
.type
,
350 ref
->key_for_search
.offset
);
354 eb
= path
->nodes
[level
];
356 if (WARN_ON(!level
)) {
361 eb
= path
->nodes
[level
];
364 ret
= add_all_parents(root
, path
, parents
, ref
, level
, time_seq
,
365 extent_item_pos
, total_refs
);
367 path
->lowest_level
= 0;
368 btrfs_release_path(path
);
373 * resolve all indirect backrefs from the list
375 static int __resolve_indirect_refs(struct btrfs_fs_info
*fs_info
,
376 struct btrfs_path
*path
, u64 time_seq
,
377 struct list_head
*head
,
378 const u64
*extent_item_pos
, u64 total_refs
)
382 struct __prelim_ref
*ref
;
383 struct __prelim_ref
*ref_safe
;
384 struct __prelim_ref
*new_ref
;
385 struct ulist
*parents
;
386 struct ulist_node
*node
;
387 struct ulist_iterator uiter
;
389 parents
= ulist_alloc(GFP_NOFS
);
394 * _safe allows us to insert directly after the current item without
395 * iterating over the newly inserted items.
396 * we're also allowed to re-assign ref during iteration.
398 list_for_each_entry_safe(ref
, ref_safe
, head
, list
) {
399 if (ref
->parent
) /* already direct */
403 err
= __resolve_indirect_ref(fs_info
, path
, time_seq
, ref
,
404 parents
, extent_item_pos
,
407 * we can only tolerate ENOENT,otherwise,we should catch error
408 * and return directly.
410 if (err
== -ENOENT
) {
417 /* we put the first parent into the ref at hand */
418 ULIST_ITER_INIT(&uiter
);
419 node
= ulist_next(parents
, &uiter
);
420 ref
->parent
= node
? node
->val
: 0;
421 ref
->inode_list
= node
?
422 (struct extent_inode_elem
*)(uintptr_t)node
->aux
: NULL
;
424 /* additional parents require new refs being added here */
425 while ((node
= ulist_next(parents
, &uiter
))) {
426 new_ref
= kmem_cache_alloc(btrfs_prelim_ref_cache
,
432 memcpy(new_ref
, ref
, sizeof(*ref
));
433 new_ref
->parent
= node
->val
;
434 new_ref
->inode_list
= (struct extent_inode_elem
*)
435 (uintptr_t)node
->aux
;
436 list_add(&new_ref
->list
, &ref
->list
);
438 ulist_reinit(parents
);
445 static inline int ref_for_same_block(struct __prelim_ref
*ref1
,
446 struct __prelim_ref
*ref2
)
448 if (ref1
->level
!= ref2
->level
)
450 if (ref1
->root_id
!= ref2
->root_id
)
452 if (ref1
->key_for_search
.type
!= ref2
->key_for_search
.type
)
454 if (ref1
->key_for_search
.objectid
!= ref2
->key_for_search
.objectid
)
456 if (ref1
->key_for_search
.offset
!= ref2
->key_for_search
.offset
)
458 if (ref1
->parent
!= ref2
->parent
)
465 * read tree blocks and add keys where required.
467 static int __add_missing_keys(struct btrfs_fs_info
*fs_info
,
468 struct list_head
*head
)
470 struct list_head
*pos
;
471 struct extent_buffer
*eb
;
473 list_for_each(pos
, head
) {
474 struct __prelim_ref
*ref
;
475 ref
= list_entry(pos
, struct __prelim_ref
, list
);
479 if (ref
->key_for_search
.type
)
481 BUG_ON(!ref
->wanted_disk_byte
);
482 eb
= read_tree_block(fs_info
->tree_root
, ref
->wanted_disk_byte
,
483 fs_info
->tree_root
->leafsize
, 0);
484 if (!eb
|| !extent_buffer_uptodate(eb
)) {
485 free_extent_buffer(eb
);
488 btrfs_tree_read_lock(eb
);
489 if (btrfs_header_level(eb
) == 0)
490 btrfs_item_key_to_cpu(eb
, &ref
->key_for_search
, 0);
492 btrfs_node_key_to_cpu(eb
, &ref
->key_for_search
, 0);
493 btrfs_tree_read_unlock(eb
);
494 free_extent_buffer(eb
);
500 * merge two lists of backrefs and adjust counts accordingly
502 * mode = 1: merge identical keys, if key is set
503 * FIXME: if we add more keys in __add_prelim_ref, we can merge more here.
504 * additionally, we could even add a key range for the blocks we
505 * looked into to merge even more (-> replace unresolved refs by those
507 * mode = 2: merge identical parents
509 static void __merge_refs(struct list_head
*head
, int mode
)
511 struct list_head
*pos1
;
513 list_for_each(pos1
, head
) {
514 struct list_head
*n2
;
515 struct list_head
*pos2
;
516 struct __prelim_ref
*ref1
;
518 ref1
= list_entry(pos1
, struct __prelim_ref
, list
);
520 for (pos2
= pos1
->next
, n2
= pos2
->next
; pos2
!= head
;
521 pos2
= n2
, n2
= pos2
->next
) {
522 struct __prelim_ref
*ref2
;
523 struct __prelim_ref
*xchg
;
524 struct extent_inode_elem
*eie
;
526 ref2
= list_entry(pos2
, struct __prelim_ref
, list
);
529 if (!ref_for_same_block(ref1
, ref2
))
531 if (!ref1
->parent
&& ref2
->parent
) {
537 if (ref1
->parent
!= ref2
->parent
)
541 eie
= ref1
->inode_list
;
542 while (eie
&& eie
->next
)
545 eie
->next
= ref2
->inode_list
;
547 ref1
->inode_list
= ref2
->inode_list
;
548 ref1
->count
+= ref2
->count
;
550 list_del(&ref2
->list
);
551 kmem_cache_free(btrfs_prelim_ref_cache
, ref2
);
558 * add all currently queued delayed refs from this head whose seq nr is
559 * smaller or equal that seq to the list
561 static int __add_delayed_refs(struct btrfs_delayed_ref_head
*head
, u64 seq
,
562 struct list_head
*prefs
, u64
*total_refs
)
564 struct btrfs_delayed_extent_op
*extent_op
= head
->extent_op
;
565 struct rb_node
*n
= &head
->node
.rb_node
;
566 struct btrfs_key key
;
567 struct btrfs_key op_key
= {0};
571 if (extent_op
&& extent_op
->update_key
)
572 btrfs_disk_key_to_cpu(&op_key
, &extent_op
->key
);
574 spin_lock(&head
->lock
);
575 n
= rb_first(&head
->ref_root
);
577 struct btrfs_delayed_ref_node
*node
;
578 node
= rb_entry(n
, struct btrfs_delayed_ref_node
,
584 switch (node
->action
) {
585 case BTRFS_ADD_DELAYED_EXTENT
:
586 case BTRFS_UPDATE_DELAYED_HEAD
:
589 case BTRFS_ADD_DELAYED_REF
:
592 case BTRFS_DROP_DELAYED_REF
:
598 *total_refs
+= (node
->ref_mod
* sgn
);
599 switch (node
->type
) {
600 case BTRFS_TREE_BLOCK_REF_KEY
: {
601 struct btrfs_delayed_tree_ref
*ref
;
603 ref
= btrfs_delayed_node_to_tree_ref(node
);
604 ret
= __add_prelim_ref(prefs
, ref
->root
, &op_key
,
605 ref
->level
+ 1, 0, node
->bytenr
,
606 node
->ref_mod
* sgn
, GFP_ATOMIC
);
609 case BTRFS_SHARED_BLOCK_REF_KEY
: {
610 struct btrfs_delayed_tree_ref
*ref
;
612 ref
= btrfs_delayed_node_to_tree_ref(node
);
613 ret
= __add_prelim_ref(prefs
, ref
->root
, NULL
,
614 ref
->level
+ 1, ref
->parent
,
616 node
->ref_mod
* sgn
, GFP_ATOMIC
);
619 case BTRFS_EXTENT_DATA_REF_KEY
: {
620 struct btrfs_delayed_data_ref
*ref
;
621 ref
= btrfs_delayed_node_to_data_ref(node
);
623 key
.objectid
= ref
->objectid
;
624 key
.type
= BTRFS_EXTENT_DATA_KEY
;
625 key
.offset
= ref
->offset
;
626 ret
= __add_prelim_ref(prefs
, ref
->root
, &key
, 0, 0,
628 node
->ref_mod
* sgn
, GFP_ATOMIC
);
631 case BTRFS_SHARED_DATA_REF_KEY
: {
632 struct btrfs_delayed_data_ref
*ref
;
634 ref
= btrfs_delayed_node_to_data_ref(node
);
636 key
.objectid
= ref
->objectid
;
637 key
.type
= BTRFS_EXTENT_DATA_KEY
;
638 key
.offset
= ref
->offset
;
639 ret
= __add_prelim_ref(prefs
, ref
->root
, &key
, 0,
640 ref
->parent
, node
->bytenr
,
641 node
->ref_mod
* sgn
, GFP_ATOMIC
);
650 spin_unlock(&head
->lock
);
655 * add all inline backrefs for bytenr to the list
657 static int __add_inline_refs(struct btrfs_fs_info
*fs_info
,
658 struct btrfs_path
*path
, u64 bytenr
,
659 int *info_level
, struct list_head
*prefs
,
664 struct extent_buffer
*leaf
;
665 struct btrfs_key key
;
666 struct btrfs_key found_key
;
669 struct btrfs_extent_item
*ei
;
674 * enumerate all inline refs
676 leaf
= path
->nodes
[0];
677 slot
= path
->slots
[0];
679 item_size
= btrfs_item_size_nr(leaf
, slot
);
680 BUG_ON(item_size
< sizeof(*ei
));
682 ei
= btrfs_item_ptr(leaf
, slot
, struct btrfs_extent_item
);
683 flags
= btrfs_extent_flags(leaf
, ei
);
684 *total_refs
+= btrfs_extent_refs(leaf
, ei
);
685 btrfs_item_key_to_cpu(leaf
, &found_key
, slot
);
687 ptr
= (unsigned long)(ei
+ 1);
688 end
= (unsigned long)ei
+ item_size
;
690 if (found_key
.type
== BTRFS_EXTENT_ITEM_KEY
&&
691 flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
) {
692 struct btrfs_tree_block_info
*info
;
694 info
= (struct btrfs_tree_block_info
*)ptr
;
695 *info_level
= btrfs_tree_block_level(leaf
, info
);
696 ptr
+= sizeof(struct btrfs_tree_block_info
);
698 } else if (found_key
.type
== BTRFS_METADATA_ITEM_KEY
) {
699 *info_level
= found_key
.offset
;
701 BUG_ON(!(flags
& BTRFS_EXTENT_FLAG_DATA
));
705 struct btrfs_extent_inline_ref
*iref
;
709 iref
= (struct btrfs_extent_inline_ref
*)ptr
;
710 type
= btrfs_extent_inline_ref_type(leaf
, iref
);
711 offset
= btrfs_extent_inline_ref_offset(leaf
, iref
);
714 case BTRFS_SHARED_BLOCK_REF_KEY
:
715 ret
= __add_prelim_ref(prefs
, 0, NULL
,
716 *info_level
+ 1, offset
,
717 bytenr
, 1, GFP_NOFS
);
719 case BTRFS_SHARED_DATA_REF_KEY
: {
720 struct btrfs_shared_data_ref
*sdref
;
723 sdref
= (struct btrfs_shared_data_ref
*)(iref
+ 1);
724 count
= btrfs_shared_data_ref_count(leaf
, sdref
);
725 ret
= __add_prelim_ref(prefs
, 0, NULL
, 0, offset
,
726 bytenr
, count
, GFP_NOFS
);
729 case BTRFS_TREE_BLOCK_REF_KEY
:
730 ret
= __add_prelim_ref(prefs
, offset
, NULL
,
732 bytenr
, 1, GFP_NOFS
);
734 case BTRFS_EXTENT_DATA_REF_KEY
: {
735 struct btrfs_extent_data_ref
*dref
;
739 dref
= (struct btrfs_extent_data_ref
*)(&iref
->offset
);
740 count
= btrfs_extent_data_ref_count(leaf
, dref
);
741 key
.objectid
= btrfs_extent_data_ref_objectid(leaf
,
743 key
.type
= BTRFS_EXTENT_DATA_KEY
;
744 key
.offset
= btrfs_extent_data_ref_offset(leaf
, dref
);
745 root
= btrfs_extent_data_ref_root(leaf
, dref
);
746 ret
= __add_prelim_ref(prefs
, root
, &key
, 0, 0,
747 bytenr
, count
, GFP_NOFS
);
755 ptr
+= btrfs_extent_inline_ref_size(type
);
762 * add all non-inline backrefs for bytenr to the list
764 static int __add_keyed_refs(struct btrfs_fs_info
*fs_info
,
765 struct btrfs_path
*path
, u64 bytenr
,
766 int info_level
, struct list_head
*prefs
)
768 struct btrfs_root
*extent_root
= fs_info
->extent_root
;
771 struct extent_buffer
*leaf
;
772 struct btrfs_key key
;
775 ret
= btrfs_next_item(extent_root
, path
);
783 slot
= path
->slots
[0];
784 leaf
= path
->nodes
[0];
785 btrfs_item_key_to_cpu(leaf
, &key
, slot
);
787 if (key
.objectid
!= bytenr
)
789 if (key
.type
< BTRFS_TREE_BLOCK_REF_KEY
)
791 if (key
.type
> BTRFS_SHARED_DATA_REF_KEY
)
795 case BTRFS_SHARED_BLOCK_REF_KEY
:
796 ret
= __add_prelim_ref(prefs
, 0, NULL
,
797 info_level
+ 1, key
.offset
,
798 bytenr
, 1, GFP_NOFS
);
800 case BTRFS_SHARED_DATA_REF_KEY
: {
801 struct btrfs_shared_data_ref
*sdref
;
804 sdref
= btrfs_item_ptr(leaf
, slot
,
805 struct btrfs_shared_data_ref
);
806 count
= btrfs_shared_data_ref_count(leaf
, sdref
);
807 ret
= __add_prelim_ref(prefs
, 0, NULL
, 0, key
.offset
,
808 bytenr
, count
, GFP_NOFS
);
811 case BTRFS_TREE_BLOCK_REF_KEY
:
812 ret
= __add_prelim_ref(prefs
, key
.offset
, NULL
,
814 bytenr
, 1, GFP_NOFS
);
816 case BTRFS_EXTENT_DATA_REF_KEY
: {
817 struct btrfs_extent_data_ref
*dref
;
821 dref
= btrfs_item_ptr(leaf
, slot
,
822 struct btrfs_extent_data_ref
);
823 count
= btrfs_extent_data_ref_count(leaf
, dref
);
824 key
.objectid
= btrfs_extent_data_ref_objectid(leaf
,
826 key
.type
= BTRFS_EXTENT_DATA_KEY
;
827 key
.offset
= btrfs_extent_data_ref_offset(leaf
, dref
);
828 root
= btrfs_extent_data_ref_root(leaf
, dref
);
829 ret
= __add_prelim_ref(prefs
, root
, &key
, 0, 0,
830 bytenr
, count
, GFP_NOFS
);
845 * this adds all existing backrefs (inline backrefs, backrefs and delayed
846 * refs) for the given bytenr to the refs list, merges duplicates and resolves
847 * indirect refs to their parent bytenr.
848 * When roots are found, they're added to the roots list
850 * FIXME some caching might speed things up
852 static int find_parent_nodes(struct btrfs_trans_handle
*trans
,
853 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
854 u64 time_seq
, struct ulist
*refs
,
855 struct ulist
*roots
, const u64
*extent_item_pos
)
857 struct btrfs_key key
;
858 struct btrfs_path
*path
;
859 struct btrfs_delayed_ref_root
*delayed_refs
= NULL
;
860 struct btrfs_delayed_ref_head
*head
;
863 struct list_head prefs_delayed
;
864 struct list_head prefs
;
865 struct __prelim_ref
*ref
;
866 struct extent_inode_elem
*eie
= NULL
;
869 INIT_LIST_HEAD(&prefs
);
870 INIT_LIST_HEAD(&prefs_delayed
);
872 key
.objectid
= bytenr
;
873 key
.offset
= (u64
)-1;
874 if (btrfs_fs_incompat(fs_info
, SKINNY_METADATA
))
875 key
.type
= BTRFS_METADATA_ITEM_KEY
;
877 key
.type
= BTRFS_EXTENT_ITEM_KEY
;
879 path
= btrfs_alloc_path();
883 path
->search_commit_root
= 1;
884 path
->skip_locking
= 1;
888 * grab both a lock on the path and a lock on the delayed ref head.
889 * We need both to get a consistent picture of how the refs look
890 * at a specified point in time
895 ret
= btrfs_search_slot(trans
, fs_info
->extent_root
, &key
, path
, 0, 0);
902 * look if there are updates for this ref queued and lock the
905 delayed_refs
= &trans
->transaction
->delayed_refs
;
906 spin_lock(&delayed_refs
->lock
);
907 head
= btrfs_find_delayed_ref_head(trans
, bytenr
);
909 if (!mutex_trylock(&head
->mutex
)) {
910 atomic_inc(&head
->node
.refs
);
911 spin_unlock(&delayed_refs
->lock
);
913 btrfs_release_path(path
);
916 * Mutex was contended, block until it's
917 * released and try again
919 mutex_lock(&head
->mutex
);
920 mutex_unlock(&head
->mutex
);
921 btrfs_put_delayed_ref(&head
->node
);
924 spin_unlock(&delayed_refs
->lock
);
925 ret
= __add_delayed_refs(head
, time_seq
,
926 &prefs_delayed
, &total_refs
);
927 mutex_unlock(&head
->mutex
);
931 spin_unlock(&delayed_refs
->lock
);
935 if (path
->slots
[0]) {
936 struct extent_buffer
*leaf
;
940 leaf
= path
->nodes
[0];
941 slot
= path
->slots
[0];
942 btrfs_item_key_to_cpu(leaf
, &key
, slot
);
943 if (key
.objectid
== bytenr
&&
944 (key
.type
== BTRFS_EXTENT_ITEM_KEY
||
945 key
.type
== BTRFS_METADATA_ITEM_KEY
)) {
946 ret
= __add_inline_refs(fs_info
, path
, bytenr
,
951 ret
= __add_keyed_refs(fs_info
, path
, bytenr
,
957 btrfs_release_path(path
);
959 list_splice_init(&prefs_delayed
, &prefs
);
961 ret
= __add_missing_keys(fs_info
, &prefs
);
965 __merge_refs(&prefs
, 1);
967 ret
= __resolve_indirect_refs(fs_info
, path
, time_seq
, &prefs
,
968 extent_item_pos
, total_refs
);
972 __merge_refs(&prefs
, 2);
974 while (!list_empty(&prefs
)) {
975 ref
= list_first_entry(&prefs
, struct __prelim_ref
, list
);
976 WARN_ON(ref
->count
< 0);
977 if (roots
&& ref
->count
&& ref
->root_id
&& ref
->parent
== 0) {
978 /* no parent == root of tree */
979 ret
= ulist_add(roots
, ref
->root_id
, 0, GFP_NOFS
);
983 if (ref
->count
&& ref
->parent
) {
984 if (extent_item_pos
&& !ref
->inode_list
) {
986 struct extent_buffer
*eb
;
987 bsz
= btrfs_level_size(fs_info
->extent_root
,
989 eb
= read_tree_block(fs_info
->extent_root
,
990 ref
->parent
, bsz
, 0);
991 if (!eb
|| !extent_buffer_uptodate(eb
)) {
992 free_extent_buffer(eb
);
996 ret
= find_extent_in_eb(eb
, bytenr
,
997 *extent_item_pos
, &eie
);
998 free_extent_buffer(eb
);
1001 ref
->inode_list
= eie
;
1003 ret
= ulist_add_merge(refs
, ref
->parent
,
1004 (uintptr_t)ref
->inode_list
,
1005 (u64
*)&eie
, GFP_NOFS
);
1008 if (!ret
&& extent_item_pos
) {
1010 * we've recorded that parent, so we must extend
1011 * its inode list here
1016 eie
->next
= ref
->inode_list
;
1020 list_del(&ref
->list
);
1021 kmem_cache_free(btrfs_prelim_ref_cache
, ref
);
1025 btrfs_free_path(path
);
1026 while (!list_empty(&prefs
)) {
1027 ref
= list_first_entry(&prefs
, struct __prelim_ref
, list
);
1028 list_del(&ref
->list
);
1029 kmem_cache_free(btrfs_prelim_ref_cache
, ref
);
1031 while (!list_empty(&prefs_delayed
)) {
1032 ref
= list_first_entry(&prefs_delayed
, struct __prelim_ref
,
1034 list_del(&ref
->list
);
1035 kmem_cache_free(btrfs_prelim_ref_cache
, ref
);
1038 free_inode_elem_list(eie
);
1042 static void free_leaf_list(struct ulist
*blocks
)
1044 struct ulist_node
*node
= NULL
;
1045 struct extent_inode_elem
*eie
;
1046 struct ulist_iterator uiter
;
1048 ULIST_ITER_INIT(&uiter
);
1049 while ((node
= ulist_next(blocks
, &uiter
))) {
1052 eie
= (struct extent_inode_elem
*)(uintptr_t)node
->aux
;
1053 free_inode_elem_list(eie
);
1061 * Finds all leafs with a reference to the specified combination of bytenr and
1062 * offset. key_list_head will point to a list of corresponding keys (caller must
1063 * free each list element). The leafs will be stored in the leafs ulist, which
1064 * must be freed with ulist_free.
1066 * returns 0 on success, <0 on error
1068 static int btrfs_find_all_leafs(struct btrfs_trans_handle
*trans
,
1069 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
1070 u64 time_seq
, struct ulist
**leafs
,
1071 const u64
*extent_item_pos
)
1075 *leafs
= ulist_alloc(GFP_NOFS
);
1079 ret
= find_parent_nodes(trans
, fs_info
, bytenr
,
1080 time_seq
, *leafs
, NULL
, extent_item_pos
);
1081 if (ret
< 0 && ret
!= -ENOENT
) {
1082 free_leaf_list(*leafs
);
1090 * walk all backrefs for a given extent to find all roots that reference this
1091 * extent. Walking a backref means finding all extents that reference this
1092 * extent and in turn walk the backrefs of those, too. Naturally this is a
1093 * recursive process, but here it is implemented in an iterative fashion: We
1094 * find all referencing extents for the extent in question and put them on a
1095 * list. In turn, we find all referencing extents for those, further appending
1096 * to the list. The way we iterate the list allows adding more elements after
1097 * the current while iterating. The process stops when we reach the end of the
1098 * list. Found roots are added to the roots list.
1100 * returns 0 on success, < 0 on error.
1102 int btrfs_find_all_roots(struct btrfs_trans_handle
*trans
,
1103 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
1104 u64 time_seq
, struct ulist
**roots
)
1107 struct ulist_node
*node
= NULL
;
1108 struct ulist_iterator uiter
;
1111 tmp
= ulist_alloc(GFP_NOFS
);
1114 *roots
= ulist_alloc(GFP_NOFS
);
1120 ULIST_ITER_INIT(&uiter
);
1122 ret
= find_parent_nodes(trans
, fs_info
, bytenr
,
1123 time_seq
, tmp
, *roots
, NULL
);
1124 if (ret
< 0 && ret
!= -ENOENT
) {
1129 node
= ulist_next(tmp
, &uiter
);
1141 * this makes the path point to (inum INODE_ITEM ioff)
1143 int inode_item_info(u64 inum
, u64 ioff
, struct btrfs_root
*fs_root
,
1144 struct btrfs_path
*path
)
1146 struct btrfs_key key
;
1147 return btrfs_find_item(fs_root
, path
, inum
, ioff
,
1148 BTRFS_INODE_ITEM_KEY
, &key
);
1151 static int inode_ref_info(u64 inum
, u64 ioff
, struct btrfs_root
*fs_root
,
1152 struct btrfs_path
*path
,
1153 struct btrfs_key
*found_key
)
1155 return btrfs_find_item(fs_root
, path
, inum
, ioff
,
1156 BTRFS_INODE_REF_KEY
, found_key
);
1159 int btrfs_find_one_extref(struct btrfs_root
*root
, u64 inode_objectid
,
1160 u64 start_off
, struct btrfs_path
*path
,
1161 struct btrfs_inode_extref
**ret_extref
,
1165 struct btrfs_key key
;
1166 struct btrfs_key found_key
;
1167 struct btrfs_inode_extref
*extref
;
1168 struct extent_buffer
*leaf
;
1171 key
.objectid
= inode_objectid
;
1172 btrfs_set_key_type(&key
, BTRFS_INODE_EXTREF_KEY
);
1173 key
.offset
= start_off
;
1175 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
1180 leaf
= path
->nodes
[0];
1181 slot
= path
->slots
[0];
1182 if (slot
>= btrfs_header_nritems(leaf
)) {
1184 * If the item at offset is not found,
1185 * btrfs_search_slot will point us to the slot
1186 * where it should be inserted. In our case
1187 * that will be the slot directly before the
1188 * next INODE_REF_KEY_V2 item. In the case
1189 * that we're pointing to the last slot in a
1190 * leaf, we must move one leaf over.
1192 ret
= btrfs_next_leaf(root
, path
);
1201 btrfs_item_key_to_cpu(leaf
, &found_key
, slot
);
1204 * Check that we're still looking at an extended ref key for
1205 * this particular objectid. If we have different
1206 * objectid or type then there are no more to be found
1207 * in the tree and we can exit.
1210 if (found_key
.objectid
!= inode_objectid
)
1212 if (btrfs_key_type(&found_key
) != BTRFS_INODE_EXTREF_KEY
)
1216 ptr
= btrfs_item_ptr_offset(leaf
, path
->slots
[0]);
1217 extref
= (struct btrfs_inode_extref
*)ptr
;
1218 *ret_extref
= extref
;
1220 *found_off
= found_key
.offset
;
1228 * this iterates to turn a name (from iref/extref) into a full filesystem path.
1229 * Elements of the path are separated by '/' and the path is guaranteed to be
1230 * 0-terminated. the path is only given within the current file system.
1231 * Therefore, it never starts with a '/'. the caller is responsible to provide
1232 * "size" bytes in "dest". the dest buffer will be filled backwards. finally,
1233 * the start point of the resulting string is returned. this pointer is within
1235 * in case the path buffer would overflow, the pointer is decremented further
1236 * as if output was written to the buffer, though no more output is actually
1237 * generated. that way, the caller can determine how much space would be
1238 * required for the path to fit into the buffer. in that case, the returned
1239 * value will be smaller than dest. callers must check this!
1241 char *btrfs_ref_to_path(struct btrfs_root
*fs_root
, struct btrfs_path
*path
,
1242 u32 name_len
, unsigned long name_off
,
1243 struct extent_buffer
*eb_in
, u64 parent
,
1244 char *dest
, u32 size
)
1249 s64 bytes_left
= ((s64
)size
) - 1;
1250 struct extent_buffer
*eb
= eb_in
;
1251 struct btrfs_key found_key
;
1252 int leave_spinning
= path
->leave_spinning
;
1253 struct btrfs_inode_ref
*iref
;
1255 if (bytes_left
>= 0)
1256 dest
[bytes_left
] = '\0';
1258 path
->leave_spinning
= 1;
1260 bytes_left
-= name_len
;
1261 if (bytes_left
>= 0)
1262 read_extent_buffer(eb
, dest
+ bytes_left
,
1263 name_off
, name_len
);
1265 btrfs_tree_read_unlock_blocking(eb
);
1266 free_extent_buffer(eb
);
1268 ret
= inode_ref_info(parent
, 0, fs_root
, path
, &found_key
);
1274 next_inum
= found_key
.offset
;
1276 /* regular exit ahead */
1277 if (parent
== next_inum
)
1280 slot
= path
->slots
[0];
1281 eb
= path
->nodes
[0];
1282 /* make sure we can use eb after releasing the path */
1284 atomic_inc(&eb
->refs
);
1285 btrfs_tree_read_lock(eb
);
1286 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1288 btrfs_release_path(path
);
1289 iref
= btrfs_item_ptr(eb
, slot
, struct btrfs_inode_ref
);
1291 name_len
= btrfs_inode_ref_name_len(eb
, iref
);
1292 name_off
= (unsigned long)(iref
+ 1);
1296 if (bytes_left
>= 0)
1297 dest
[bytes_left
] = '/';
1300 btrfs_release_path(path
);
1301 path
->leave_spinning
= leave_spinning
;
1304 return ERR_PTR(ret
);
1306 return dest
+ bytes_left
;
1310 * this makes the path point to (logical EXTENT_ITEM *)
1311 * returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for
1312 * tree blocks and <0 on error.
1314 int extent_from_logical(struct btrfs_fs_info
*fs_info
, u64 logical
,
1315 struct btrfs_path
*path
, struct btrfs_key
*found_key
,
1322 struct extent_buffer
*eb
;
1323 struct btrfs_extent_item
*ei
;
1324 struct btrfs_key key
;
1326 if (btrfs_fs_incompat(fs_info
, SKINNY_METADATA
))
1327 key
.type
= BTRFS_METADATA_ITEM_KEY
;
1329 key
.type
= BTRFS_EXTENT_ITEM_KEY
;
1330 key
.objectid
= logical
;
1331 key
.offset
= (u64
)-1;
1333 ret
= btrfs_search_slot(NULL
, fs_info
->extent_root
, &key
, path
, 0, 0);
1337 ret
= btrfs_previous_extent_item(fs_info
->extent_root
, path
, 0);
1343 btrfs_item_key_to_cpu(path
->nodes
[0], found_key
, path
->slots
[0]);
1344 if (found_key
->type
== BTRFS_METADATA_ITEM_KEY
)
1345 size
= fs_info
->extent_root
->leafsize
;
1346 else if (found_key
->type
== BTRFS_EXTENT_ITEM_KEY
)
1347 size
= found_key
->offset
;
1349 if (found_key
->objectid
> logical
||
1350 found_key
->objectid
+ size
<= logical
) {
1351 pr_debug("logical %llu is not within any extent\n", logical
);
1355 eb
= path
->nodes
[0];
1356 item_size
= btrfs_item_size_nr(eb
, path
->slots
[0]);
1357 BUG_ON(item_size
< sizeof(*ei
));
1359 ei
= btrfs_item_ptr(eb
, path
->slots
[0], struct btrfs_extent_item
);
1360 flags
= btrfs_extent_flags(eb
, ei
);
1362 pr_debug("logical %llu is at position %llu within the extent (%llu "
1363 "EXTENT_ITEM %llu) flags %#llx size %u\n",
1364 logical
, logical
- found_key
->objectid
, found_key
->objectid
,
1365 found_key
->offset
, flags
, item_size
);
1367 WARN_ON(!flags_ret
);
1369 if (flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
)
1370 *flags_ret
= BTRFS_EXTENT_FLAG_TREE_BLOCK
;
1371 else if (flags
& BTRFS_EXTENT_FLAG_DATA
)
1372 *flags_ret
= BTRFS_EXTENT_FLAG_DATA
;
1382 * helper function to iterate extent inline refs. ptr must point to a 0 value
1383 * for the first call and may be modified. it is used to track state.
1384 * if more refs exist, 0 is returned and the next call to
1385 * __get_extent_inline_ref must pass the modified ptr parameter to get the
1386 * next ref. after the last ref was processed, 1 is returned.
1387 * returns <0 on error
1389 static int __get_extent_inline_ref(unsigned long *ptr
, struct extent_buffer
*eb
,
1390 struct btrfs_extent_item
*ei
, u32 item_size
,
1391 struct btrfs_extent_inline_ref
**out_eiref
,
1396 struct btrfs_tree_block_info
*info
;
1400 flags
= btrfs_extent_flags(eb
, ei
);
1401 if (flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
) {
1402 info
= (struct btrfs_tree_block_info
*)(ei
+ 1);
1404 (struct btrfs_extent_inline_ref
*)(info
+ 1);
1406 *out_eiref
= (struct btrfs_extent_inline_ref
*)(ei
+ 1);
1408 *ptr
= (unsigned long)*out_eiref
;
1409 if ((void *)*ptr
>= (void *)ei
+ item_size
)
1413 end
= (unsigned long)ei
+ item_size
;
1414 *out_eiref
= (struct btrfs_extent_inline_ref
*)*ptr
;
1415 *out_type
= btrfs_extent_inline_ref_type(eb
, *out_eiref
);
1417 *ptr
+= btrfs_extent_inline_ref_size(*out_type
);
1418 WARN_ON(*ptr
> end
);
1420 return 1; /* last */
1426 * reads the tree block backref for an extent. tree level and root are returned
1427 * through out_level and out_root. ptr must point to a 0 value for the first
1428 * call and may be modified (see __get_extent_inline_ref comment).
1429 * returns 0 if data was provided, 1 if there was no more data to provide or
1432 int tree_backref_for_extent(unsigned long *ptr
, struct extent_buffer
*eb
,
1433 struct btrfs_extent_item
*ei
, u32 item_size
,
1434 u64
*out_root
, u8
*out_level
)
1438 struct btrfs_tree_block_info
*info
;
1439 struct btrfs_extent_inline_ref
*eiref
;
1441 if (*ptr
== (unsigned long)-1)
1445 ret
= __get_extent_inline_ref(ptr
, eb
, ei
, item_size
,
1450 if (type
== BTRFS_TREE_BLOCK_REF_KEY
||
1451 type
== BTRFS_SHARED_BLOCK_REF_KEY
)
1458 /* we can treat both ref types equally here */
1459 info
= (struct btrfs_tree_block_info
*)(ei
+ 1);
1460 *out_root
= btrfs_extent_inline_ref_offset(eb
, eiref
);
1461 *out_level
= btrfs_tree_block_level(eb
, info
);
1464 *ptr
= (unsigned long)-1;
1469 static int iterate_leaf_refs(struct extent_inode_elem
*inode_list
,
1470 u64 root
, u64 extent_item_objectid
,
1471 iterate_extent_inodes_t
*iterate
, void *ctx
)
1473 struct extent_inode_elem
*eie
;
1476 for (eie
= inode_list
; eie
; eie
= eie
->next
) {
1477 pr_debug("ref for %llu resolved, key (%llu EXTEND_DATA %llu), "
1478 "root %llu\n", extent_item_objectid
,
1479 eie
->inum
, eie
->offset
, root
);
1480 ret
= iterate(eie
->inum
, eie
->offset
, root
, ctx
);
1482 pr_debug("stopping iteration for %llu due to ret=%d\n",
1483 extent_item_objectid
, ret
);
1492 * calls iterate() for every inode that references the extent identified by
1493 * the given parameters.
1494 * when the iterator function returns a non-zero value, iteration stops.
1496 int iterate_extent_inodes(struct btrfs_fs_info
*fs_info
,
1497 u64 extent_item_objectid
, u64 extent_item_pos
,
1498 int search_commit_root
,
1499 iterate_extent_inodes_t
*iterate
, void *ctx
)
1502 struct btrfs_trans_handle
*trans
= NULL
;
1503 struct ulist
*refs
= NULL
;
1504 struct ulist
*roots
= NULL
;
1505 struct ulist_node
*ref_node
= NULL
;
1506 struct ulist_node
*root_node
= NULL
;
1507 struct seq_list tree_mod_seq_elem
= {};
1508 struct ulist_iterator ref_uiter
;
1509 struct ulist_iterator root_uiter
;
1511 pr_debug("resolving all inodes for extent %llu\n",
1512 extent_item_objectid
);
1514 if (!search_commit_root
) {
1515 trans
= btrfs_join_transaction(fs_info
->extent_root
);
1517 return PTR_ERR(trans
);
1518 btrfs_get_tree_mod_seq(fs_info
, &tree_mod_seq_elem
);
1521 ret
= btrfs_find_all_leafs(trans
, fs_info
, extent_item_objectid
,
1522 tree_mod_seq_elem
.seq
, &refs
,
1527 ULIST_ITER_INIT(&ref_uiter
);
1528 while (!ret
&& (ref_node
= ulist_next(refs
, &ref_uiter
))) {
1529 ret
= btrfs_find_all_roots(trans
, fs_info
, ref_node
->val
,
1530 tree_mod_seq_elem
.seq
, &roots
);
1533 ULIST_ITER_INIT(&root_uiter
);
1534 while (!ret
&& (root_node
= ulist_next(roots
, &root_uiter
))) {
1535 pr_debug("root %llu references leaf %llu, data list "
1536 "%#llx\n", root_node
->val
, ref_node
->val
,
1538 ret
= iterate_leaf_refs((struct extent_inode_elem
*)
1539 (uintptr_t)ref_node
->aux
,
1541 extent_item_objectid
,
1547 free_leaf_list(refs
);
1549 if (!search_commit_root
) {
1550 btrfs_put_tree_mod_seq(fs_info
, &tree_mod_seq_elem
);
1551 btrfs_end_transaction(trans
, fs_info
->extent_root
);
1557 int iterate_inodes_from_logical(u64 logical
, struct btrfs_fs_info
*fs_info
,
1558 struct btrfs_path
*path
,
1559 iterate_extent_inodes_t
*iterate
, void *ctx
)
1562 u64 extent_item_pos
;
1564 struct btrfs_key found_key
;
1565 int search_commit_root
= path
->search_commit_root
;
1567 ret
= extent_from_logical(fs_info
, logical
, path
, &found_key
, &flags
);
1568 btrfs_release_path(path
);
1571 if (flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
)
1574 extent_item_pos
= logical
- found_key
.objectid
;
1575 ret
= iterate_extent_inodes(fs_info
, found_key
.objectid
,
1576 extent_item_pos
, search_commit_root
,
1582 typedef int (iterate_irefs_t
)(u64 parent
, u32 name_len
, unsigned long name_off
,
1583 struct extent_buffer
*eb
, void *ctx
);
1585 static int iterate_inode_refs(u64 inum
, struct btrfs_root
*fs_root
,
1586 struct btrfs_path
*path
,
1587 iterate_irefs_t
*iterate
, void *ctx
)
1596 struct extent_buffer
*eb
;
1597 struct btrfs_item
*item
;
1598 struct btrfs_inode_ref
*iref
;
1599 struct btrfs_key found_key
;
1602 ret
= inode_ref_info(inum
, parent
? parent
+1 : 0, fs_root
, path
,
1607 ret
= found
? 0 : -ENOENT
;
1612 parent
= found_key
.offset
;
1613 slot
= path
->slots
[0];
1614 eb
= btrfs_clone_extent_buffer(path
->nodes
[0]);
1619 extent_buffer_get(eb
);
1620 btrfs_tree_read_lock(eb
);
1621 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1622 btrfs_release_path(path
);
1624 item
= btrfs_item_nr(slot
);
1625 iref
= btrfs_item_ptr(eb
, slot
, struct btrfs_inode_ref
);
1627 for (cur
= 0; cur
< btrfs_item_size(eb
, item
); cur
+= len
) {
1628 name_len
= btrfs_inode_ref_name_len(eb
, iref
);
1629 /* path must be released before calling iterate()! */
1630 pr_debug("following ref at offset %u for inode %llu in "
1631 "tree %llu\n", cur
, found_key
.objectid
,
1633 ret
= iterate(parent
, name_len
,
1634 (unsigned long)(iref
+ 1), eb
, ctx
);
1637 len
= sizeof(*iref
) + name_len
;
1638 iref
= (struct btrfs_inode_ref
*)((char *)iref
+ len
);
1640 btrfs_tree_read_unlock_blocking(eb
);
1641 free_extent_buffer(eb
);
1644 btrfs_release_path(path
);
1649 static int iterate_inode_extrefs(u64 inum
, struct btrfs_root
*fs_root
,
1650 struct btrfs_path
*path
,
1651 iterate_irefs_t
*iterate
, void *ctx
)
1658 struct extent_buffer
*eb
;
1659 struct btrfs_inode_extref
*extref
;
1660 struct extent_buffer
*leaf
;
1666 ret
= btrfs_find_one_extref(fs_root
, inum
, offset
, path
, &extref
,
1671 ret
= found
? 0 : -ENOENT
;
1676 slot
= path
->slots
[0];
1677 eb
= btrfs_clone_extent_buffer(path
->nodes
[0]);
1682 extent_buffer_get(eb
);
1684 btrfs_tree_read_lock(eb
);
1685 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1686 btrfs_release_path(path
);
1688 leaf
= path
->nodes
[0];
1689 item_size
= btrfs_item_size_nr(leaf
, slot
);
1690 ptr
= btrfs_item_ptr_offset(leaf
, slot
);
1693 while (cur_offset
< item_size
) {
1696 extref
= (struct btrfs_inode_extref
*)(ptr
+ cur_offset
);
1697 parent
= btrfs_inode_extref_parent(eb
, extref
);
1698 name_len
= btrfs_inode_extref_name_len(eb
, extref
);
1699 ret
= iterate(parent
, name_len
,
1700 (unsigned long)&extref
->name
, eb
, ctx
);
1704 cur_offset
+= btrfs_inode_extref_name_len(leaf
, extref
);
1705 cur_offset
+= sizeof(*extref
);
1707 btrfs_tree_read_unlock_blocking(eb
);
1708 free_extent_buffer(eb
);
1713 btrfs_release_path(path
);
1718 static int iterate_irefs(u64 inum
, struct btrfs_root
*fs_root
,
1719 struct btrfs_path
*path
, iterate_irefs_t
*iterate
,
1725 ret
= iterate_inode_refs(inum
, fs_root
, path
, iterate
, ctx
);
1728 else if (ret
!= -ENOENT
)
1731 ret
= iterate_inode_extrefs(inum
, fs_root
, path
, iterate
, ctx
);
1732 if (ret
== -ENOENT
&& found_refs
)
1739 * returns 0 if the path could be dumped (probably truncated)
1740 * returns <0 in case of an error
1742 static int inode_to_path(u64 inum
, u32 name_len
, unsigned long name_off
,
1743 struct extent_buffer
*eb
, void *ctx
)
1745 struct inode_fs_paths
*ipath
= ctx
;
1748 int i
= ipath
->fspath
->elem_cnt
;
1749 const int s_ptr
= sizeof(char *);
1752 bytes_left
= ipath
->fspath
->bytes_left
> s_ptr
?
1753 ipath
->fspath
->bytes_left
- s_ptr
: 0;
1755 fspath_min
= (char *)ipath
->fspath
->val
+ (i
+ 1) * s_ptr
;
1756 fspath
= btrfs_ref_to_path(ipath
->fs_root
, ipath
->btrfs_path
, name_len
,
1757 name_off
, eb
, inum
, fspath_min
, bytes_left
);
1759 return PTR_ERR(fspath
);
1761 if (fspath
> fspath_min
) {
1762 ipath
->fspath
->val
[i
] = (u64
)(unsigned long)fspath
;
1763 ++ipath
->fspath
->elem_cnt
;
1764 ipath
->fspath
->bytes_left
= fspath
- fspath_min
;
1766 ++ipath
->fspath
->elem_missed
;
1767 ipath
->fspath
->bytes_missing
+= fspath_min
- fspath
;
1768 ipath
->fspath
->bytes_left
= 0;
1775 * this dumps all file system paths to the inode into the ipath struct, provided
1776 * is has been created large enough. each path is zero-terminated and accessed
1777 * from ipath->fspath->val[i].
1778 * when it returns, there are ipath->fspath->elem_cnt number of paths available
1779 * in ipath->fspath->val[]. when the allocated space wasn't sufficient, the
1780 * number of missed paths in recored in ipath->fspath->elem_missed, otherwise,
1781 * it's zero. ipath->fspath->bytes_missing holds the number of bytes that would
1782 * have been needed to return all paths.
1784 int paths_from_inode(u64 inum
, struct inode_fs_paths
*ipath
)
1786 return iterate_irefs(inum
, ipath
->fs_root
, ipath
->btrfs_path
,
1787 inode_to_path
, ipath
);
1790 struct btrfs_data_container
*init_data_container(u32 total_bytes
)
1792 struct btrfs_data_container
*data
;
1795 alloc_bytes
= max_t(size_t, total_bytes
, sizeof(*data
));
1796 data
= vmalloc(alloc_bytes
);
1798 return ERR_PTR(-ENOMEM
);
1800 if (total_bytes
>= sizeof(*data
)) {
1801 data
->bytes_left
= total_bytes
- sizeof(*data
);
1802 data
->bytes_missing
= 0;
1804 data
->bytes_missing
= sizeof(*data
) - total_bytes
;
1805 data
->bytes_left
= 0;
1809 data
->elem_missed
= 0;
1815 * allocates space to return multiple file system paths for an inode.
1816 * total_bytes to allocate are passed, note that space usable for actual path
1817 * information will be total_bytes - sizeof(struct inode_fs_paths).
1818 * the returned pointer must be freed with free_ipath() in the end.
1820 struct inode_fs_paths
*init_ipath(s32 total_bytes
, struct btrfs_root
*fs_root
,
1821 struct btrfs_path
*path
)
1823 struct inode_fs_paths
*ifp
;
1824 struct btrfs_data_container
*fspath
;
1826 fspath
= init_data_container(total_bytes
);
1828 return (void *)fspath
;
1830 ifp
= kmalloc(sizeof(*ifp
), GFP_NOFS
);
1833 return ERR_PTR(-ENOMEM
);
1836 ifp
->btrfs_path
= path
;
1837 ifp
->fspath
= fspath
;
1838 ifp
->fs_root
= fs_root
;
1843 void free_ipath(struct inode_fs_paths
*ipath
)
1847 vfree(ipath
->fspath
);