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 /* Just an arbitrary number so we can be sure this happened */
29 #define BACKREF_FOUND_SHARED 6
31 struct extent_inode_elem
{
34 struct extent_inode_elem
*next
;
37 static int check_extent_in_eb(struct btrfs_key
*key
, struct extent_buffer
*eb
,
38 struct btrfs_file_extent_item
*fi
,
40 struct extent_inode_elem
**eie
)
43 struct extent_inode_elem
*e
;
45 if (!btrfs_file_extent_compression(eb
, fi
) &&
46 !btrfs_file_extent_encryption(eb
, fi
) &&
47 !btrfs_file_extent_other_encoding(eb
, fi
)) {
51 data_offset
= btrfs_file_extent_offset(eb
, fi
);
52 data_len
= btrfs_file_extent_num_bytes(eb
, fi
);
54 if (extent_item_pos
< data_offset
||
55 extent_item_pos
>= data_offset
+ data_len
)
57 offset
= extent_item_pos
- data_offset
;
60 e
= kmalloc(sizeof(*e
), GFP_NOFS
);
65 e
->inum
= key
->objectid
;
66 e
->offset
= key
->offset
+ offset
;
72 static void free_inode_elem_list(struct extent_inode_elem
*eie
)
74 struct extent_inode_elem
*eie_next
;
76 for (; eie
; eie
= eie_next
) {
82 static int find_extent_in_eb(struct extent_buffer
*eb
, u64 wanted_disk_byte
,
84 struct extent_inode_elem
**eie
)
88 struct btrfs_file_extent_item
*fi
;
95 * from the shared data ref, we only have the leaf but we need
96 * the key. thus, we must look into all items and see that we
97 * find one (some) with a reference to our extent item.
99 nritems
= btrfs_header_nritems(eb
);
100 for (slot
= 0; slot
< nritems
; ++slot
) {
101 btrfs_item_key_to_cpu(eb
, &key
, slot
);
102 if (key
.type
!= BTRFS_EXTENT_DATA_KEY
)
104 fi
= btrfs_item_ptr(eb
, slot
, struct btrfs_file_extent_item
);
105 extent_type
= btrfs_file_extent_type(eb
, fi
);
106 if (extent_type
== BTRFS_FILE_EXTENT_INLINE
)
108 /* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */
109 disk_byte
= btrfs_file_extent_disk_bytenr(eb
, fi
);
110 if (disk_byte
!= wanted_disk_byte
)
113 ret
= check_extent_in_eb(&key
, eb
, fi
, extent_item_pos
, eie
);
122 * this structure records all encountered refs on the way up to the root
124 struct __prelim_ref
{
125 struct list_head list
;
127 struct btrfs_key key_for_search
;
130 struct extent_inode_elem
*inode_list
;
132 u64 wanted_disk_byte
;
135 static struct kmem_cache
*btrfs_prelim_ref_cache
;
137 int __init
btrfs_prelim_ref_init(void)
139 btrfs_prelim_ref_cache
= kmem_cache_create("btrfs_prelim_ref",
140 sizeof(struct __prelim_ref
),
142 SLAB_RECLAIM_ACCOUNT
| SLAB_MEM_SPREAD
,
144 if (!btrfs_prelim_ref_cache
)
149 void btrfs_prelim_ref_exit(void)
151 if (btrfs_prelim_ref_cache
)
152 kmem_cache_destroy(btrfs_prelim_ref_cache
);
156 * the rules for all callers of this function are:
157 * - obtaining the parent is the goal
158 * - if you add a key, you must know that it is a correct key
159 * - if you cannot add the parent or a correct key, then we will look into the
160 * block later to set a correct key
164 * backref type | shared | indirect | shared | indirect
165 * information | tree | tree | data | data
166 * --------------------+--------+----------+--------+----------
167 * parent logical | y | - | - | -
168 * key to resolve | - | y | y | y
169 * tree block logical | - | - | - | -
170 * root for resolving | y | y | y | y
172 * - column 1: we've the parent -> done
173 * - column 2, 3, 4: we use the key to find the parent
175 * on disk refs (inline or keyed)
176 * ==============================
177 * backref type | shared | indirect | shared | indirect
178 * information | tree | tree | data | data
179 * --------------------+--------+----------+--------+----------
180 * parent logical | y | - | y | -
181 * key to resolve | - | - | - | y
182 * tree block logical | y | y | y | y
183 * root for resolving | - | y | y | y
185 * - column 1, 3: we've the parent -> done
186 * - column 2: we take the first key from the block to find the parent
187 * (see __add_missing_keys)
188 * - column 4: we use the key to find the parent
190 * additional information that's available but not required to find the parent
191 * block might help in merging entries to gain some speed.
194 static int __add_prelim_ref(struct list_head
*head
, u64 root_id
,
195 struct btrfs_key
*key
, int level
,
196 u64 parent
, u64 wanted_disk_byte
, int count
,
199 struct __prelim_ref
*ref
;
201 if (root_id
== BTRFS_DATA_RELOC_TREE_OBJECTID
)
204 ref
= kmem_cache_alloc(btrfs_prelim_ref_cache
, gfp_mask
);
208 ref
->root_id
= root_id
;
210 ref
->key_for_search
= *key
;
212 * We can often find data backrefs with an offset that is too
213 * large (>= LLONG_MAX, maximum allowed file offset) due to
214 * underflows when subtracting a file's offset with the data
215 * offset of its corresponding extent data item. This can
216 * happen for example in the clone ioctl.
217 * So if we detect such case we set the search key's offset to
218 * zero to make sure we will find the matching file extent item
219 * at add_all_parents(), otherwise we will miss it because the
220 * offset taken form the backref is much larger then the offset
221 * of the file extent item. This can make us scan a very large
222 * number of file extent items, but at least it will not make
224 * This is an ugly workaround for a behaviour that should have
225 * never existed, but it does and a fix for the clone ioctl
226 * would touch a lot of places, cause backwards incompatibility
227 * and would not fix the problem for extents cloned with older
230 if (ref
->key_for_search
.type
== BTRFS_EXTENT_DATA_KEY
&&
231 ref
->key_for_search
.offset
>= LLONG_MAX
)
232 ref
->key_for_search
.offset
= 0;
234 memset(&ref
->key_for_search
, 0, sizeof(ref
->key_for_search
));
237 ref
->inode_list
= NULL
;
240 ref
->parent
= parent
;
241 ref
->wanted_disk_byte
= wanted_disk_byte
;
242 list_add_tail(&ref
->list
, head
);
247 static int add_all_parents(struct btrfs_root
*root
, struct btrfs_path
*path
,
248 struct ulist
*parents
, struct __prelim_ref
*ref
,
249 int level
, u64 time_seq
, const u64
*extent_item_pos
,
254 struct extent_buffer
*eb
;
255 struct btrfs_key key
;
256 struct btrfs_key
*key_for_search
= &ref
->key_for_search
;
257 struct btrfs_file_extent_item
*fi
;
258 struct extent_inode_elem
*eie
= NULL
, *old
= NULL
;
260 u64 wanted_disk_byte
= ref
->wanted_disk_byte
;
264 eb
= path
->nodes
[level
];
265 ret
= ulist_add(parents
, eb
->start
, 0, GFP_NOFS
);
272 * We normally enter this function with the path already pointing to
273 * the first item to check. But sometimes, we may enter it with
274 * slot==nritems. In that case, go to the next leaf before we continue.
276 if (path
->slots
[0] >= btrfs_header_nritems(path
->nodes
[0])) {
277 if (time_seq
== (u64
)-1)
278 ret
= btrfs_next_leaf(root
, path
);
280 ret
= btrfs_next_old_leaf(root
, path
, time_seq
);
283 while (!ret
&& count
< total_refs
) {
285 slot
= path
->slots
[0];
287 btrfs_item_key_to_cpu(eb
, &key
, slot
);
289 if (key
.objectid
!= key_for_search
->objectid
||
290 key
.type
!= BTRFS_EXTENT_DATA_KEY
)
293 fi
= btrfs_item_ptr(eb
, slot
, struct btrfs_file_extent_item
);
294 disk_byte
= btrfs_file_extent_disk_bytenr(eb
, fi
);
296 if (disk_byte
== wanted_disk_byte
) {
300 if (extent_item_pos
) {
301 ret
= check_extent_in_eb(&key
, eb
, fi
,
309 ret
= ulist_add_merge_ptr(parents
, eb
->start
,
310 eie
, (void **)&old
, GFP_NOFS
);
313 if (!ret
&& extent_item_pos
) {
321 if (time_seq
== (u64
)-1)
322 ret
= btrfs_next_item(root
, path
);
324 ret
= btrfs_next_old_item(root
, path
, time_seq
);
330 free_inode_elem_list(eie
);
335 * resolve an indirect backref in the form (root_id, key, level)
336 * to a logical address
338 static int __resolve_indirect_ref(struct btrfs_fs_info
*fs_info
,
339 struct btrfs_path
*path
, u64 time_seq
,
340 struct __prelim_ref
*ref
,
341 struct ulist
*parents
,
342 const u64
*extent_item_pos
, u64 total_refs
)
344 struct btrfs_root
*root
;
345 struct btrfs_key root_key
;
346 struct extent_buffer
*eb
;
349 int level
= ref
->level
;
352 root_key
.objectid
= ref
->root_id
;
353 root_key
.type
= BTRFS_ROOT_ITEM_KEY
;
354 root_key
.offset
= (u64
)-1;
356 index
= srcu_read_lock(&fs_info
->subvol_srcu
);
358 root
= btrfs_get_fs_root(fs_info
, &root_key
, false);
360 srcu_read_unlock(&fs_info
->subvol_srcu
, index
);
365 if (btrfs_test_is_dummy_root(root
)) {
366 srcu_read_unlock(&fs_info
->subvol_srcu
, index
);
371 if (path
->search_commit_root
)
372 root_level
= btrfs_header_level(root
->commit_root
);
373 else if (time_seq
== (u64
)-1)
374 root_level
= btrfs_header_level(root
->node
);
376 root_level
= btrfs_old_root_level(root
, time_seq
);
378 if (root_level
+ 1 == level
) {
379 srcu_read_unlock(&fs_info
->subvol_srcu
, index
);
383 path
->lowest_level
= level
;
384 if (time_seq
== (u64
)-1)
385 ret
= btrfs_search_slot(NULL
, root
, &ref
->key_for_search
, path
,
388 ret
= btrfs_search_old_slot(root
, &ref
->key_for_search
, path
,
391 /* root node has been locked, we can release @subvol_srcu safely here */
392 srcu_read_unlock(&fs_info
->subvol_srcu
, index
);
394 pr_debug("search slot in root %llu (level %d, ref count %d) returned "
395 "%d for key (%llu %u %llu)\n",
396 ref
->root_id
, level
, ref
->count
, ret
,
397 ref
->key_for_search
.objectid
, ref
->key_for_search
.type
,
398 ref
->key_for_search
.offset
);
402 eb
= path
->nodes
[level
];
404 if (WARN_ON(!level
)) {
409 eb
= path
->nodes
[level
];
412 ret
= add_all_parents(root
, path
, parents
, ref
, level
, time_seq
,
413 extent_item_pos
, total_refs
);
415 path
->lowest_level
= 0;
416 btrfs_release_path(path
);
421 * resolve all indirect backrefs from the list
423 static int __resolve_indirect_refs(struct btrfs_fs_info
*fs_info
,
424 struct btrfs_path
*path
, u64 time_seq
,
425 struct list_head
*head
,
426 const u64
*extent_item_pos
, u64 total_refs
,
431 struct __prelim_ref
*ref
;
432 struct __prelim_ref
*ref_safe
;
433 struct __prelim_ref
*new_ref
;
434 struct ulist
*parents
;
435 struct ulist_node
*node
;
436 struct ulist_iterator uiter
;
438 parents
= ulist_alloc(GFP_NOFS
);
443 * _safe allows us to insert directly after the current item without
444 * iterating over the newly inserted items.
445 * we're also allowed to re-assign ref during iteration.
447 list_for_each_entry_safe(ref
, ref_safe
, head
, list
) {
448 if (ref
->parent
) /* already direct */
452 if (root_objectid
&& ref
->root_id
!= root_objectid
) {
453 ret
= BACKREF_FOUND_SHARED
;
456 err
= __resolve_indirect_ref(fs_info
, path
, time_seq
, ref
,
457 parents
, extent_item_pos
,
460 * we can only tolerate ENOENT,otherwise,we should catch error
461 * and return directly.
463 if (err
== -ENOENT
) {
470 /* we put the first parent into the ref at hand */
471 ULIST_ITER_INIT(&uiter
);
472 node
= ulist_next(parents
, &uiter
);
473 ref
->parent
= node
? node
->val
: 0;
474 ref
->inode_list
= node
?
475 (struct extent_inode_elem
*)(uintptr_t)node
->aux
: NULL
;
477 /* additional parents require new refs being added here */
478 while ((node
= ulist_next(parents
, &uiter
))) {
479 new_ref
= kmem_cache_alloc(btrfs_prelim_ref_cache
,
485 memcpy(new_ref
, ref
, sizeof(*ref
));
486 new_ref
->parent
= node
->val
;
487 new_ref
->inode_list
= (struct extent_inode_elem
*)
488 (uintptr_t)node
->aux
;
489 list_add(&new_ref
->list
, &ref
->list
);
491 ulist_reinit(parents
);
498 static inline int ref_for_same_block(struct __prelim_ref
*ref1
,
499 struct __prelim_ref
*ref2
)
501 if (ref1
->level
!= ref2
->level
)
503 if (ref1
->root_id
!= ref2
->root_id
)
505 if (ref1
->key_for_search
.type
!= ref2
->key_for_search
.type
)
507 if (ref1
->key_for_search
.objectid
!= ref2
->key_for_search
.objectid
)
509 if (ref1
->key_for_search
.offset
!= ref2
->key_for_search
.offset
)
511 if (ref1
->parent
!= ref2
->parent
)
518 * read tree blocks and add keys where required.
520 static int __add_missing_keys(struct btrfs_fs_info
*fs_info
,
521 struct list_head
*head
)
523 struct __prelim_ref
*ref
;
524 struct extent_buffer
*eb
;
526 list_for_each_entry(ref
, head
, list
) {
529 if (ref
->key_for_search
.type
)
531 BUG_ON(!ref
->wanted_disk_byte
);
532 eb
= read_tree_block(fs_info
->tree_root
, ref
->wanted_disk_byte
,
536 } else if (!extent_buffer_uptodate(eb
)) {
537 free_extent_buffer(eb
);
540 btrfs_tree_read_lock(eb
);
541 if (btrfs_header_level(eb
) == 0)
542 btrfs_item_key_to_cpu(eb
, &ref
->key_for_search
, 0);
544 btrfs_node_key_to_cpu(eb
, &ref
->key_for_search
, 0);
545 btrfs_tree_read_unlock(eb
);
546 free_extent_buffer(eb
);
552 * merge backrefs and adjust counts accordingly
554 * mode = 1: merge identical keys, if key is set
555 * FIXME: if we add more keys in __add_prelim_ref, we can merge more here.
556 * additionally, we could even add a key range for the blocks we
557 * looked into to merge even more (-> replace unresolved refs by those
559 * mode = 2: merge identical parents
561 static void __merge_refs(struct list_head
*head
, int mode
)
563 struct __prelim_ref
*pos1
;
565 list_for_each_entry(pos1
, head
, list
) {
566 struct __prelim_ref
*pos2
= pos1
, *tmp
;
568 list_for_each_entry_safe_continue(pos2
, tmp
, head
, list
) {
569 struct __prelim_ref
*xchg
, *ref1
= pos1
, *ref2
= pos2
;
570 struct extent_inode_elem
*eie
;
572 if (!ref_for_same_block(ref1
, ref2
))
575 if (!ref1
->parent
&& ref2
->parent
) {
581 if (ref1
->parent
!= ref2
->parent
)
585 eie
= ref1
->inode_list
;
586 while (eie
&& eie
->next
)
589 eie
->next
= ref2
->inode_list
;
591 ref1
->inode_list
= ref2
->inode_list
;
592 ref1
->count
+= ref2
->count
;
594 list_del(&ref2
->list
);
595 kmem_cache_free(btrfs_prelim_ref_cache
, ref2
);
602 * add all currently queued delayed refs from this head whose seq nr is
603 * smaller or equal that seq to the list
605 static int __add_delayed_refs(struct btrfs_delayed_ref_head
*head
, u64 seq
,
606 struct list_head
*prefs
, u64
*total_refs
,
609 struct btrfs_delayed_ref_node
*node
;
610 struct btrfs_delayed_extent_op
*extent_op
= head
->extent_op
;
611 struct btrfs_key key
;
612 struct btrfs_key op_key
= {0};
616 if (extent_op
&& extent_op
->update_key
)
617 btrfs_disk_key_to_cpu(&op_key
, &extent_op
->key
);
619 spin_lock(&head
->lock
);
620 list_for_each_entry(node
, &head
->ref_list
, list
) {
624 switch (node
->action
) {
625 case BTRFS_ADD_DELAYED_EXTENT
:
626 case BTRFS_UPDATE_DELAYED_HEAD
:
629 case BTRFS_ADD_DELAYED_REF
:
632 case BTRFS_DROP_DELAYED_REF
:
638 *total_refs
+= (node
->ref_mod
* sgn
);
639 switch (node
->type
) {
640 case BTRFS_TREE_BLOCK_REF_KEY
: {
641 struct btrfs_delayed_tree_ref
*ref
;
643 ref
= btrfs_delayed_node_to_tree_ref(node
);
644 ret
= __add_prelim_ref(prefs
, ref
->root
, &op_key
,
645 ref
->level
+ 1, 0, node
->bytenr
,
646 node
->ref_mod
* sgn
, GFP_ATOMIC
);
649 case BTRFS_SHARED_BLOCK_REF_KEY
: {
650 struct btrfs_delayed_tree_ref
*ref
;
652 ref
= btrfs_delayed_node_to_tree_ref(node
);
653 ret
= __add_prelim_ref(prefs
, 0, NULL
,
654 ref
->level
+ 1, ref
->parent
,
656 node
->ref_mod
* sgn
, GFP_ATOMIC
);
659 case BTRFS_EXTENT_DATA_REF_KEY
: {
660 struct btrfs_delayed_data_ref
*ref
;
661 ref
= btrfs_delayed_node_to_data_ref(node
);
663 key
.objectid
= ref
->objectid
;
664 key
.type
= BTRFS_EXTENT_DATA_KEY
;
665 key
.offset
= ref
->offset
;
668 * Found a inum that doesn't match our known inum, we
671 if (inum
&& ref
->objectid
!= inum
) {
672 ret
= BACKREF_FOUND_SHARED
;
676 ret
= __add_prelim_ref(prefs
, ref
->root
, &key
, 0, 0,
678 node
->ref_mod
* sgn
, GFP_ATOMIC
);
681 case BTRFS_SHARED_DATA_REF_KEY
: {
682 struct btrfs_delayed_data_ref
*ref
;
684 ref
= btrfs_delayed_node_to_data_ref(node
);
685 ret
= __add_prelim_ref(prefs
, 0, NULL
, 0,
686 ref
->parent
, node
->bytenr
,
687 node
->ref_mod
* sgn
, GFP_ATOMIC
);
696 spin_unlock(&head
->lock
);
701 * add all inline backrefs for bytenr to the list
703 static int __add_inline_refs(struct btrfs_fs_info
*fs_info
,
704 struct btrfs_path
*path
, u64 bytenr
,
705 int *info_level
, struct list_head
*prefs
,
706 u64
*total_refs
, u64 inum
)
710 struct extent_buffer
*leaf
;
711 struct btrfs_key key
;
712 struct btrfs_key found_key
;
715 struct btrfs_extent_item
*ei
;
720 * enumerate all inline refs
722 leaf
= path
->nodes
[0];
723 slot
= path
->slots
[0];
725 item_size
= btrfs_item_size_nr(leaf
, slot
);
726 BUG_ON(item_size
< sizeof(*ei
));
728 ei
= btrfs_item_ptr(leaf
, slot
, struct btrfs_extent_item
);
729 flags
= btrfs_extent_flags(leaf
, ei
);
730 *total_refs
+= btrfs_extent_refs(leaf
, ei
);
731 btrfs_item_key_to_cpu(leaf
, &found_key
, slot
);
733 ptr
= (unsigned long)(ei
+ 1);
734 end
= (unsigned long)ei
+ item_size
;
736 if (found_key
.type
== BTRFS_EXTENT_ITEM_KEY
&&
737 flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
) {
738 struct btrfs_tree_block_info
*info
;
740 info
= (struct btrfs_tree_block_info
*)ptr
;
741 *info_level
= btrfs_tree_block_level(leaf
, info
);
742 ptr
+= sizeof(struct btrfs_tree_block_info
);
744 } else if (found_key
.type
== BTRFS_METADATA_ITEM_KEY
) {
745 *info_level
= found_key
.offset
;
747 BUG_ON(!(flags
& BTRFS_EXTENT_FLAG_DATA
));
751 struct btrfs_extent_inline_ref
*iref
;
755 iref
= (struct btrfs_extent_inline_ref
*)ptr
;
756 type
= btrfs_extent_inline_ref_type(leaf
, iref
);
757 offset
= btrfs_extent_inline_ref_offset(leaf
, iref
);
760 case BTRFS_SHARED_BLOCK_REF_KEY
:
761 ret
= __add_prelim_ref(prefs
, 0, NULL
,
762 *info_level
+ 1, offset
,
763 bytenr
, 1, GFP_NOFS
);
765 case BTRFS_SHARED_DATA_REF_KEY
: {
766 struct btrfs_shared_data_ref
*sdref
;
769 sdref
= (struct btrfs_shared_data_ref
*)(iref
+ 1);
770 count
= btrfs_shared_data_ref_count(leaf
, sdref
);
771 ret
= __add_prelim_ref(prefs
, 0, NULL
, 0, offset
,
772 bytenr
, count
, GFP_NOFS
);
775 case BTRFS_TREE_BLOCK_REF_KEY
:
776 ret
= __add_prelim_ref(prefs
, offset
, NULL
,
778 bytenr
, 1, GFP_NOFS
);
780 case BTRFS_EXTENT_DATA_REF_KEY
: {
781 struct btrfs_extent_data_ref
*dref
;
785 dref
= (struct btrfs_extent_data_ref
*)(&iref
->offset
);
786 count
= btrfs_extent_data_ref_count(leaf
, dref
);
787 key
.objectid
= btrfs_extent_data_ref_objectid(leaf
,
789 key
.type
= BTRFS_EXTENT_DATA_KEY
;
790 key
.offset
= btrfs_extent_data_ref_offset(leaf
, dref
);
792 if (inum
&& key
.objectid
!= inum
) {
793 ret
= BACKREF_FOUND_SHARED
;
797 root
= btrfs_extent_data_ref_root(leaf
, dref
);
798 ret
= __add_prelim_ref(prefs
, root
, &key
, 0, 0,
799 bytenr
, count
, GFP_NOFS
);
807 ptr
+= btrfs_extent_inline_ref_size(type
);
814 * add all non-inline backrefs for bytenr to the list
816 static int __add_keyed_refs(struct btrfs_fs_info
*fs_info
,
817 struct btrfs_path
*path
, u64 bytenr
,
818 int info_level
, struct list_head
*prefs
, u64 inum
)
820 struct btrfs_root
*extent_root
= fs_info
->extent_root
;
823 struct extent_buffer
*leaf
;
824 struct btrfs_key key
;
827 ret
= btrfs_next_item(extent_root
, path
);
835 slot
= path
->slots
[0];
836 leaf
= path
->nodes
[0];
837 btrfs_item_key_to_cpu(leaf
, &key
, slot
);
839 if (key
.objectid
!= bytenr
)
841 if (key
.type
< BTRFS_TREE_BLOCK_REF_KEY
)
843 if (key
.type
> BTRFS_SHARED_DATA_REF_KEY
)
847 case BTRFS_SHARED_BLOCK_REF_KEY
:
848 ret
= __add_prelim_ref(prefs
, 0, NULL
,
849 info_level
+ 1, key
.offset
,
850 bytenr
, 1, GFP_NOFS
);
852 case BTRFS_SHARED_DATA_REF_KEY
: {
853 struct btrfs_shared_data_ref
*sdref
;
856 sdref
= btrfs_item_ptr(leaf
, slot
,
857 struct btrfs_shared_data_ref
);
858 count
= btrfs_shared_data_ref_count(leaf
, sdref
);
859 ret
= __add_prelim_ref(prefs
, 0, NULL
, 0, key
.offset
,
860 bytenr
, count
, GFP_NOFS
);
863 case BTRFS_TREE_BLOCK_REF_KEY
:
864 ret
= __add_prelim_ref(prefs
, key
.offset
, NULL
,
866 bytenr
, 1, GFP_NOFS
);
868 case BTRFS_EXTENT_DATA_REF_KEY
: {
869 struct btrfs_extent_data_ref
*dref
;
873 dref
= btrfs_item_ptr(leaf
, slot
,
874 struct btrfs_extent_data_ref
);
875 count
= btrfs_extent_data_ref_count(leaf
, dref
);
876 key
.objectid
= btrfs_extent_data_ref_objectid(leaf
,
878 key
.type
= BTRFS_EXTENT_DATA_KEY
;
879 key
.offset
= btrfs_extent_data_ref_offset(leaf
, dref
);
881 if (inum
&& key
.objectid
!= inum
) {
882 ret
= BACKREF_FOUND_SHARED
;
886 root
= btrfs_extent_data_ref_root(leaf
, dref
);
887 ret
= __add_prelim_ref(prefs
, root
, &key
, 0, 0,
888 bytenr
, count
, GFP_NOFS
);
903 * this adds all existing backrefs (inline backrefs, backrefs and delayed
904 * refs) for the given bytenr to the refs list, merges duplicates and resolves
905 * indirect refs to their parent bytenr.
906 * When roots are found, they're added to the roots list
908 * NOTE: This can return values > 0
910 * If time_seq is set to (u64)-1, it will not search delayed_refs, and behave
911 * much like trans == NULL case, the difference only lies in it will not
913 * The special case is for qgroup to search roots in commit_transaction().
915 * FIXME some caching might speed things up
917 static int find_parent_nodes(struct btrfs_trans_handle
*trans
,
918 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
919 u64 time_seq
, struct ulist
*refs
,
920 struct ulist
*roots
, const u64
*extent_item_pos
,
921 u64 root_objectid
, u64 inum
)
923 struct btrfs_key key
;
924 struct btrfs_path
*path
;
925 struct btrfs_delayed_ref_root
*delayed_refs
= NULL
;
926 struct btrfs_delayed_ref_head
*head
;
929 struct list_head prefs_delayed
;
930 struct list_head prefs
;
931 struct __prelim_ref
*ref
;
932 struct extent_inode_elem
*eie
= NULL
;
935 INIT_LIST_HEAD(&prefs
);
936 INIT_LIST_HEAD(&prefs_delayed
);
938 key
.objectid
= bytenr
;
939 key
.offset
= (u64
)-1;
940 if (btrfs_fs_incompat(fs_info
, SKINNY_METADATA
))
941 key
.type
= BTRFS_METADATA_ITEM_KEY
;
943 key
.type
= BTRFS_EXTENT_ITEM_KEY
;
945 path
= btrfs_alloc_path();
949 path
->search_commit_root
= 1;
950 path
->skip_locking
= 1;
953 if (time_seq
== (u64
)-1)
954 path
->skip_locking
= 1;
957 * grab both a lock on the path and a lock on the delayed ref head.
958 * We need both to get a consistent picture of how the refs look
959 * at a specified point in time
964 ret
= btrfs_search_slot(trans
, fs_info
->extent_root
, &key
, path
, 0, 0);
969 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
970 if (trans
&& likely(trans
->type
!= __TRANS_DUMMY
) &&
971 time_seq
!= (u64
)-1) {
973 if (trans
&& time_seq
!= (u64
)-1) {
976 * look if there are updates for this ref queued and lock the
979 delayed_refs
= &trans
->transaction
->delayed_refs
;
980 spin_lock(&delayed_refs
->lock
);
981 head
= btrfs_find_delayed_ref_head(trans
, bytenr
);
983 if (!mutex_trylock(&head
->mutex
)) {
984 atomic_inc(&head
->node
.refs
);
985 spin_unlock(&delayed_refs
->lock
);
987 btrfs_release_path(path
);
990 * Mutex was contended, block until it's
991 * released and try again
993 mutex_lock(&head
->mutex
);
994 mutex_unlock(&head
->mutex
);
995 btrfs_put_delayed_ref(&head
->node
);
998 spin_unlock(&delayed_refs
->lock
);
999 ret
= __add_delayed_refs(head
, time_seq
,
1000 &prefs_delayed
, &total_refs
,
1002 mutex_unlock(&head
->mutex
);
1006 spin_unlock(&delayed_refs
->lock
);
1010 if (path
->slots
[0]) {
1011 struct extent_buffer
*leaf
;
1015 leaf
= path
->nodes
[0];
1016 slot
= path
->slots
[0];
1017 btrfs_item_key_to_cpu(leaf
, &key
, slot
);
1018 if (key
.objectid
== bytenr
&&
1019 (key
.type
== BTRFS_EXTENT_ITEM_KEY
||
1020 key
.type
== BTRFS_METADATA_ITEM_KEY
)) {
1021 ret
= __add_inline_refs(fs_info
, path
, bytenr
,
1022 &info_level
, &prefs
,
1026 ret
= __add_keyed_refs(fs_info
, path
, bytenr
,
1027 info_level
, &prefs
, inum
);
1032 btrfs_release_path(path
);
1034 list_splice_init(&prefs_delayed
, &prefs
);
1036 ret
= __add_missing_keys(fs_info
, &prefs
);
1040 __merge_refs(&prefs
, 1);
1042 ret
= __resolve_indirect_refs(fs_info
, path
, time_seq
, &prefs
,
1043 extent_item_pos
, total_refs
,
1048 __merge_refs(&prefs
, 2);
1050 while (!list_empty(&prefs
)) {
1051 ref
= list_first_entry(&prefs
, struct __prelim_ref
, list
);
1052 WARN_ON(ref
->count
< 0);
1053 if (roots
&& ref
->count
&& ref
->root_id
&& ref
->parent
== 0) {
1054 if (root_objectid
&& ref
->root_id
!= root_objectid
) {
1055 ret
= BACKREF_FOUND_SHARED
;
1059 /* no parent == root of tree */
1060 ret
= ulist_add(roots
, ref
->root_id
, 0, GFP_NOFS
);
1064 if (ref
->count
&& ref
->parent
) {
1065 if (extent_item_pos
&& !ref
->inode_list
&&
1067 struct extent_buffer
*eb
;
1069 eb
= read_tree_block(fs_info
->extent_root
,
1074 } else if (!extent_buffer_uptodate(eb
)) {
1075 free_extent_buffer(eb
);
1079 btrfs_tree_read_lock(eb
);
1080 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1081 ret
= find_extent_in_eb(eb
, bytenr
,
1082 *extent_item_pos
, &eie
);
1083 btrfs_tree_read_unlock_blocking(eb
);
1084 free_extent_buffer(eb
);
1087 ref
->inode_list
= eie
;
1089 ret
= ulist_add_merge_ptr(refs
, ref
->parent
,
1091 (void **)&eie
, GFP_NOFS
);
1094 if (!ret
&& extent_item_pos
) {
1096 * we've recorded that parent, so we must extend
1097 * its inode list here
1102 eie
->next
= ref
->inode_list
;
1106 list_del(&ref
->list
);
1107 kmem_cache_free(btrfs_prelim_ref_cache
, ref
);
1111 btrfs_free_path(path
);
1112 while (!list_empty(&prefs
)) {
1113 ref
= list_first_entry(&prefs
, struct __prelim_ref
, list
);
1114 list_del(&ref
->list
);
1115 kmem_cache_free(btrfs_prelim_ref_cache
, ref
);
1117 while (!list_empty(&prefs_delayed
)) {
1118 ref
= list_first_entry(&prefs_delayed
, struct __prelim_ref
,
1120 list_del(&ref
->list
);
1121 kmem_cache_free(btrfs_prelim_ref_cache
, ref
);
1124 free_inode_elem_list(eie
);
1128 static void free_leaf_list(struct ulist
*blocks
)
1130 struct ulist_node
*node
= NULL
;
1131 struct extent_inode_elem
*eie
;
1132 struct ulist_iterator uiter
;
1134 ULIST_ITER_INIT(&uiter
);
1135 while ((node
= ulist_next(blocks
, &uiter
))) {
1138 eie
= (struct extent_inode_elem
*)(uintptr_t)node
->aux
;
1139 free_inode_elem_list(eie
);
1147 * Finds all leafs with a reference to the specified combination of bytenr and
1148 * offset. key_list_head will point to a list of corresponding keys (caller must
1149 * free each list element). The leafs will be stored in the leafs ulist, which
1150 * must be freed with ulist_free.
1152 * returns 0 on success, <0 on error
1154 static int btrfs_find_all_leafs(struct btrfs_trans_handle
*trans
,
1155 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
1156 u64 time_seq
, struct ulist
**leafs
,
1157 const u64
*extent_item_pos
)
1161 *leafs
= ulist_alloc(GFP_NOFS
);
1165 ret
= find_parent_nodes(trans
, fs_info
, bytenr
,
1166 time_seq
, *leafs
, NULL
, extent_item_pos
, 0, 0);
1167 if (ret
< 0 && ret
!= -ENOENT
) {
1168 free_leaf_list(*leafs
);
1176 * walk all backrefs for a given extent to find all roots that reference this
1177 * extent. Walking a backref means finding all extents that reference this
1178 * extent and in turn walk the backrefs of those, too. Naturally this is a
1179 * recursive process, but here it is implemented in an iterative fashion: We
1180 * find all referencing extents for the extent in question and put them on a
1181 * list. In turn, we find all referencing extents for those, further appending
1182 * to the list. The way we iterate the list allows adding more elements after
1183 * the current while iterating. The process stops when we reach the end of the
1184 * list. Found roots are added to the roots list.
1186 * returns 0 on success, < 0 on error.
1188 static int __btrfs_find_all_roots(struct btrfs_trans_handle
*trans
,
1189 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
1190 u64 time_seq
, struct ulist
**roots
)
1193 struct ulist_node
*node
= NULL
;
1194 struct ulist_iterator uiter
;
1197 tmp
= ulist_alloc(GFP_NOFS
);
1200 *roots
= ulist_alloc(GFP_NOFS
);
1206 ULIST_ITER_INIT(&uiter
);
1208 ret
= find_parent_nodes(trans
, fs_info
, bytenr
,
1209 time_seq
, tmp
, *roots
, NULL
, 0, 0);
1210 if (ret
< 0 && ret
!= -ENOENT
) {
1215 node
= ulist_next(tmp
, &uiter
);
1226 int btrfs_find_all_roots(struct btrfs_trans_handle
*trans
,
1227 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
1228 u64 time_seq
, struct ulist
**roots
)
1233 down_read(&fs_info
->commit_root_sem
);
1234 ret
= __btrfs_find_all_roots(trans
, fs_info
, bytenr
, time_seq
, roots
);
1236 up_read(&fs_info
->commit_root_sem
);
1241 * btrfs_check_shared - tell us whether an extent is shared
1243 * @trans: optional trans handle
1245 * btrfs_check_shared uses the backref walking code but will short
1246 * circuit as soon as it finds a root or inode that doesn't match the
1247 * one passed in. This provides a significant performance benefit for
1248 * callers (such as fiemap) which want to know whether the extent is
1249 * shared but do not need a ref count.
1251 * Return: 0 if extent is not shared, 1 if it is shared, < 0 on error.
1253 int btrfs_check_shared(struct btrfs_trans_handle
*trans
,
1254 struct btrfs_fs_info
*fs_info
, u64 root_objectid
,
1255 u64 inum
, u64 bytenr
)
1257 struct ulist
*tmp
= NULL
;
1258 struct ulist
*roots
= NULL
;
1259 struct ulist_iterator uiter
;
1260 struct ulist_node
*node
;
1261 struct seq_list elem
= SEQ_LIST_INIT(elem
);
1264 tmp
= ulist_alloc(GFP_NOFS
);
1265 roots
= ulist_alloc(GFP_NOFS
);
1266 if (!tmp
|| !roots
) {
1273 btrfs_get_tree_mod_seq(fs_info
, &elem
);
1275 down_read(&fs_info
->commit_root_sem
);
1276 ULIST_ITER_INIT(&uiter
);
1278 ret
= find_parent_nodes(trans
, fs_info
, bytenr
, elem
.seq
, tmp
,
1279 roots
, NULL
, root_objectid
, inum
);
1280 if (ret
== BACKREF_FOUND_SHARED
) {
1281 /* this is the only condition under which we return 1 */
1285 if (ret
< 0 && ret
!= -ENOENT
)
1288 node
= ulist_next(tmp
, &uiter
);
1295 btrfs_put_tree_mod_seq(fs_info
, &elem
);
1297 up_read(&fs_info
->commit_root_sem
);
1303 int btrfs_find_one_extref(struct btrfs_root
*root
, u64 inode_objectid
,
1304 u64 start_off
, struct btrfs_path
*path
,
1305 struct btrfs_inode_extref
**ret_extref
,
1309 struct btrfs_key key
;
1310 struct btrfs_key found_key
;
1311 struct btrfs_inode_extref
*extref
;
1312 struct extent_buffer
*leaf
;
1315 key
.objectid
= inode_objectid
;
1316 key
.type
= BTRFS_INODE_EXTREF_KEY
;
1317 key
.offset
= start_off
;
1319 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
1324 leaf
= path
->nodes
[0];
1325 slot
= path
->slots
[0];
1326 if (slot
>= btrfs_header_nritems(leaf
)) {
1328 * If the item at offset is not found,
1329 * btrfs_search_slot will point us to the slot
1330 * where it should be inserted. In our case
1331 * that will be the slot directly before the
1332 * next INODE_REF_KEY_V2 item. In the case
1333 * that we're pointing to the last slot in a
1334 * leaf, we must move one leaf over.
1336 ret
= btrfs_next_leaf(root
, path
);
1345 btrfs_item_key_to_cpu(leaf
, &found_key
, slot
);
1348 * Check that we're still looking at an extended ref key for
1349 * this particular objectid. If we have different
1350 * objectid or type then there are no more to be found
1351 * in the tree and we can exit.
1354 if (found_key
.objectid
!= inode_objectid
)
1356 if (found_key
.type
!= BTRFS_INODE_EXTREF_KEY
)
1360 ptr
= btrfs_item_ptr_offset(leaf
, path
->slots
[0]);
1361 extref
= (struct btrfs_inode_extref
*)ptr
;
1362 *ret_extref
= extref
;
1364 *found_off
= found_key
.offset
;
1372 * this iterates to turn a name (from iref/extref) into a full filesystem path.
1373 * Elements of the path are separated by '/' and the path is guaranteed to be
1374 * 0-terminated. the path is only given within the current file system.
1375 * Therefore, it never starts with a '/'. the caller is responsible to provide
1376 * "size" bytes in "dest". the dest buffer will be filled backwards. finally,
1377 * the start point of the resulting string is returned. this pointer is within
1379 * in case the path buffer would overflow, the pointer is decremented further
1380 * as if output was written to the buffer, though no more output is actually
1381 * generated. that way, the caller can determine how much space would be
1382 * required for the path to fit into the buffer. in that case, the returned
1383 * value will be smaller than dest. callers must check this!
1385 char *btrfs_ref_to_path(struct btrfs_root
*fs_root
, struct btrfs_path
*path
,
1386 u32 name_len
, unsigned long name_off
,
1387 struct extent_buffer
*eb_in
, u64 parent
,
1388 char *dest
, u32 size
)
1393 s64 bytes_left
= ((s64
)size
) - 1;
1394 struct extent_buffer
*eb
= eb_in
;
1395 struct btrfs_key found_key
;
1396 int leave_spinning
= path
->leave_spinning
;
1397 struct btrfs_inode_ref
*iref
;
1399 if (bytes_left
>= 0)
1400 dest
[bytes_left
] = '\0';
1402 path
->leave_spinning
= 1;
1404 bytes_left
-= name_len
;
1405 if (bytes_left
>= 0)
1406 read_extent_buffer(eb
, dest
+ bytes_left
,
1407 name_off
, name_len
);
1409 if (!path
->skip_locking
)
1410 btrfs_tree_read_unlock_blocking(eb
);
1411 free_extent_buffer(eb
);
1413 ret
= btrfs_find_item(fs_root
, path
, parent
, 0,
1414 BTRFS_INODE_REF_KEY
, &found_key
);
1420 next_inum
= found_key
.offset
;
1422 /* regular exit ahead */
1423 if (parent
== next_inum
)
1426 slot
= path
->slots
[0];
1427 eb
= path
->nodes
[0];
1428 /* make sure we can use eb after releasing the path */
1430 if (!path
->skip_locking
)
1431 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1432 path
->nodes
[0] = NULL
;
1435 btrfs_release_path(path
);
1436 iref
= btrfs_item_ptr(eb
, slot
, struct btrfs_inode_ref
);
1438 name_len
= btrfs_inode_ref_name_len(eb
, iref
);
1439 name_off
= (unsigned long)(iref
+ 1);
1443 if (bytes_left
>= 0)
1444 dest
[bytes_left
] = '/';
1447 btrfs_release_path(path
);
1448 path
->leave_spinning
= leave_spinning
;
1451 return ERR_PTR(ret
);
1453 return dest
+ bytes_left
;
1457 * this makes the path point to (logical EXTENT_ITEM *)
1458 * returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for
1459 * tree blocks and <0 on error.
1461 int extent_from_logical(struct btrfs_fs_info
*fs_info
, u64 logical
,
1462 struct btrfs_path
*path
, struct btrfs_key
*found_key
,
1469 struct extent_buffer
*eb
;
1470 struct btrfs_extent_item
*ei
;
1471 struct btrfs_key key
;
1473 if (btrfs_fs_incompat(fs_info
, SKINNY_METADATA
))
1474 key
.type
= BTRFS_METADATA_ITEM_KEY
;
1476 key
.type
= BTRFS_EXTENT_ITEM_KEY
;
1477 key
.objectid
= logical
;
1478 key
.offset
= (u64
)-1;
1480 ret
= btrfs_search_slot(NULL
, fs_info
->extent_root
, &key
, path
, 0, 0);
1484 ret
= btrfs_previous_extent_item(fs_info
->extent_root
, path
, 0);
1490 btrfs_item_key_to_cpu(path
->nodes
[0], found_key
, path
->slots
[0]);
1491 if (found_key
->type
== BTRFS_METADATA_ITEM_KEY
)
1492 size
= fs_info
->extent_root
->nodesize
;
1493 else if (found_key
->type
== BTRFS_EXTENT_ITEM_KEY
)
1494 size
= found_key
->offset
;
1496 if (found_key
->objectid
> logical
||
1497 found_key
->objectid
+ size
<= logical
) {
1498 pr_debug("logical %llu is not within any extent\n", logical
);
1502 eb
= path
->nodes
[0];
1503 item_size
= btrfs_item_size_nr(eb
, path
->slots
[0]);
1504 BUG_ON(item_size
< sizeof(*ei
));
1506 ei
= btrfs_item_ptr(eb
, path
->slots
[0], struct btrfs_extent_item
);
1507 flags
= btrfs_extent_flags(eb
, ei
);
1509 pr_debug("logical %llu is at position %llu within the extent (%llu "
1510 "EXTENT_ITEM %llu) flags %#llx size %u\n",
1511 logical
, logical
- found_key
->objectid
, found_key
->objectid
,
1512 found_key
->offset
, flags
, item_size
);
1514 WARN_ON(!flags_ret
);
1516 if (flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
)
1517 *flags_ret
= BTRFS_EXTENT_FLAG_TREE_BLOCK
;
1518 else if (flags
& BTRFS_EXTENT_FLAG_DATA
)
1519 *flags_ret
= BTRFS_EXTENT_FLAG_DATA
;
1529 * helper function to iterate extent inline refs. ptr must point to a 0 value
1530 * for the first call and may be modified. it is used to track state.
1531 * if more refs exist, 0 is returned and the next call to
1532 * __get_extent_inline_ref must pass the modified ptr parameter to get the
1533 * next ref. after the last ref was processed, 1 is returned.
1534 * returns <0 on error
1536 static int __get_extent_inline_ref(unsigned long *ptr
, struct extent_buffer
*eb
,
1537 struct btrfs_key
*key
,
1538 struct btrfs_extent_item
*ei
, u32 item_size
,
1539 struct btrfs_extent_inline_ref
**out_eiref
,
1544 struct btrfs_tree_block_info
*info
;
1548 flags
= btrfs_extent_flags(eb
, ei
);
1549 if (flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
) {
1550 if (key
->type
== BTRFS_METADATA_ITEM_KEY
) {
1551 /* a skinny metadata extent */
1553 (struct btrfs_extent_inline_ref
*)(ei
+ 1);
1555 WARN_ON(key
->type
!= BTRFS_EXTENT_ITEM_KEY
);
1556 info
= (struct btrfs_tree_block_info
*)(ei
+ 1);
1558 (struct btrfs_extent_inline_ref
*)(info
+ 1);
1561 *out_eiref
= (struct btrfs_extent_inline_ref
*)(ei
+ 1);
1563 *ptr
= (unsigned long)*out_eiref
;
1564 if ((unsigned long)(*ptr
) >= (unsigned long)ei
+ item_size
)
1568 end
= (unsigned long)ei
+ item_size
;
1569 *out_eiref
= (struct btrfs_extent_inline_ref
*)(*ptr
);
1570 *out_type
= btrfs_extent_inline_ref_type(eb
, *out_eiref
);
1572 *ptr
+= btrfs_extent_inline_ref_size(*out_type
);
1573 WARN_ON(*ptr
> end
);
1575 return 1; /* last */
1581 * reads the tree block backref for an extent. tree level and root are returned
1582 * through out_level and out_root. ptr must point to a 0 value for the first
1583 * call and may be modified (see __get_extent_inline_ref comment).
1584 * returns 0 if data was provided, 1 if there was no more data to provide or
1587 int tree_backref_for_extent(unsigned long *ptr
, struct extent_buffer
*eb
,
1588 struct btrfs_key
*key
, struct btrfs_extent_item
*ei
,
1589 u32 item_size
, u64
*out_root
, u8
*out_level
)
1593 struct btrfs_extent_inline_ref
*eiref
;
1595 if (*ptr
== (unsigned long)-1)
1599 ret
= __get_extent_inline_ref(ptr
, eb
, key
, ei
, item_size
,
1604 if (type
== BTRFS_TREE_BLOCK_REF_KEY
||
1605 type
== BTRFS_SHARED_BLOCK_REF_KEY
)
1612 /* we can treat both ref types equally here */
1613 *out_root
= btrfs_extent_inline_ref_offset(eb
, eiref
);
1615 if (key
->type
== BTRFS_EXTENT_ITEM_KEY
) {
1616 struct btrfs_tree_block_info
*info
;
1618 info
= (struct btrfs_tree_block_info
*)(ei
+ 1);
1619 *out_level
= btrfs_tree_block_level(eb
, info
);
1621 ASSERT(key
->type
== BTRFS_METADATA_ITEM_KEY
);
1622 *out_level
= (u8
)key
->offset
;
1626 *ptr
= (unsigned long)-1;
1631 static int iterate_leaf_refs(struct extent_inode_elem
*inode_list
,
1632 u64 root
, u64 extent_item_objectid
,
1633 iterate_extent_inodes_t
*iterate
, void *ctx
)
1635 struct extent_inode_elem
*eie
;
1638 for (eie
= inode_list
; eie
; eie
= eie
->next
) {
1639 pr_debug("ref for %llu resolved, key (%llu EXTEND_DATA %llu), "
1640 "root %llu\n", extent_item_objectid
,
1641 eie
->inum
, eie
->offset
, root
);
1642 ret
= iterate(eie
->inum
, eie
->offset
, root
, ctx
);
1644 pr_debug("stopping iteration for %llu due to ret=%d\n",
1645 extent_item_objectid
, ret
);
1654 * calls iterate() for every inode that references the extent identified by
1655 * the given parameters.
1656 * when the iterator function returns a non-zero value, iteration stops.
1658 int iterate_extent_inodes(struct btrfs_fs_info
*fs_info
,
1659 u64 extent_item_objectid
, u64 extent_item_pos
,
1660 int search_commit_root
,
1661 iterate_extent_inodes_t
*iterate
, void *ctx
)
1664 struct btrfs_trans_handle
*trans
= NULL
;
1665 struct ulist
*refs
= NULL
;
1666 struct ulist
*roots
= NULL
;
1667 struct ulist_node
*ref_node
= NULL
;
1668 struct ulist_node
*root_node
= NULL
;
1669 struct seq_list tree_mod_seq_elem
= SEQ_LIST_INIT(tree_mod_seq_elem
);
1670 struct ulist_iterator ref_uiter
;
1671 struct ulist_iterator root_uiter
;
1673 pr_debug("resolving all inodes for extent %llu\n",
1674 extent_item_objectid
);
1676 if (!search_commit_root
) {
1677 trans
= btrfs_join_transaction(fs_info
->extent_root
);
1679 return PTR_ERR(trans
);
1680 btrfs_get_tree_mod_seq(fs_info
, &tree_mod_seq_elem
);
1682 down_read(&fs_info
->commit_root_sem
);
1685 ret
= btrfs_find_all_leafs(trans
, fs_info
, extent_item_objectid
,
1686 tree_mod_seq_elem
.seq
, &refs
,
1691 ULIST_ITER_INIT(&ref_uiter
);
1692 while (!ret
&& (ref_node
= ulist_next(refs
, &ref_uiter
))) {
1693 ret
= __btrfs_find_all_roots(trans
, fs_info
, ref_node
->val
,
1694 tree_mod_seq_elem
.seq
, &roots
);
1697 ULIST_ITER_INIT(&root_uiter
);
1698 while (!ret
&& (root_node
= ulist_next(roots
, &root_uiter
))) {
1699 pr_debug("root %llu references leaf %llu, data list "
1700 "%#llx\n", root_node
->val
, ref_node
->val
,
1702 ret
= iterate_leaf_refs((struct extent_inode_elem
*)
1703 (uintptr_t)ref_node
->aux
,
1705 extent_item_objectid
,
1711 free_leaf_list(refs
);
1713 if (!search_commit_root
) {
1714 btrfs_put_tree_mod_seq(fs_info
, &tree_mod_seq_elem
);
1715 btrfs_end_transaction(trans
, fs_info
->extent_root
);
1717 up_read(&fs_info
->commit_root_sem
);
1723 int iterate_inodes_from_logical(u64 logical
, struct btrfs_fs_info
*fs_info
,
1724 struct btrfs_path
*path
,
1725 iterate_extent_inodes_t
*iterate
, void *ctx
)
1728 u64 extent_item_pos
;
1730 struct btrfs_key found_key
;
1731 int search_commit_root
= path
->search_commit_root
;
1733 ret
= extent_from_logical(fs_info
, logical
, path
, &found_key
, &flags
);
1734 btrfs_release_path(path
);
1737 if (flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
)
1740 extent_item_pos
= logical
- found_key
.objectid
;
1741 ret
= iterate_extent_inodes(fs_info
, found_key
.objectid
,
1742 extent_item_pos
, search_commit_root
,
1748 typedef int (iterate_irefs_t
)(u64 parent
, u32 name_len
, unsigned long name_off
,
1749 struct extent_buffer
*eb
, void *ctx
);
1751 static int iterate_inode_refs(u64 inum
, struct btrfs_root
*fs_root
,
1752 struct btrfs_path
*path
,
1753 iterate_irefs_t
*iterate
, void *ctx
)
1762 struct extent_buffer
*eb
;
1763 struct btrfs_item
*item
;
1764 struct btrfs_inode_ref
*iref
;
1765 struct btrfs_key found_key
;
1768 ret
= btrfs_find_item(fs_root
, path
, inum
,
1769 parent
? parent
+ 1 : 0, BTRFS_INODE_REF_KEY
,
1775 ret
= found
? 0 : -ENOENT
;
1780 parent
= found_key
.offset
;
1781 slot
= path
->slots
[0];
1782 eb
= btrfs_clone_extent_buffer(path
->nodes
[0]);
1787 extent_buffer_get(eb
);
1788 btrfs_tree_read_lock(eb
);
1789 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1790 btrfs_release_path(path
);
1792 item
= btrfs_item_nr(slot
);
1793 iref
= btrfs_item_ptr(eb
, slot
, struct btrfs_inode_ref
);
1795 for (cur
= 0; cur
< btrfs_item_size(eb
, item
); cur
+= len
) {
1796 name_len
= btrfs_inode_ref_name_len(eb
, iref
);
1797 /* path must be released before calling iterate()! */
1798 pr_debug("following ref at offset %u for inode %llu in "
1799 "tree %llu\n", cur
, found_key
.objectid
,
1801 ret
= iterate(parent
, name_len
,
1802 (unsigned long)(iref
+ 1), eb
, ctx
);
1805 len
= sizeof(*iref
) + name_len
;
1806 iref
= (struct btrfs_inode_ref
*)((char *)iref
+ len
);
1808 btrfs_tree_read_unlock_blocking(eb
);
1809 free_extent_buffer(eb
);
1812 btrfs_release_path(path
);
1817 static int iterate_inode_extrefs(u64 inum
, struct btrfs_root
*fs_root
,
1818 struct btrfs_path
*path
,
1819 iterate_irefs_t
*iterate
, void *ctx
)
1826 struct extent_buffer
*eb
;
1827 struct btrfs_inode_extref
*extref
;
1833 ret
= btrfs_find_one_extref(fs_root
, inum
, offset
, path
, &extref
,
1838 ret
= found
? 0 : -ENOENT
;
1843 slot
= path
->slots
[0];
1844 eb
= btrfs_clone_extent_buffer(path
->nodes
[0]);
1849 extent_buffer_get(eb
);
1851 btrfs_tree_read_lock(eb
);
1852 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1853 btrfs_release_path(path
);
1855 item_size
= btrfs_item_size_nr(eb
, slot
);
1856 ptr
= btrfs_item_ptr_offset(eb
, slot
);
1859 while (cur_offset
< item_size
) {
1862 extref
= (struct btrfs_inode_extref
*)(ptr
+ cur_offset
);
1863 parent
= btrfs_inode_extref_parent(eb
, extref
);
1864 name_len
= btrfs_inode_extref_name_len(eb
, extref
);
1865 ret
= iterate(parent
, name_len
,
1866 (unsigned long)&extref
->name
, eb
, ctx
);
1870 cur_offset
+= btrfs_inode_extref_name_len(eb
, extref
);
1871 cur_offset
+= sizeof(*extref
);
1873 btrfs_tree_read_unlock_blocking(eb
);
1874 free_extent_buffer(eb
);
1879 btrfs_release_path(path
);
1884 static int iterate_irefs(u64 inum
, struct btrfs_root
*fs_root
,
1885 struct btrfs_path
*path
, iterate_irefs_t
*iterate
,
1891 ret
= iterate_inode_refs(inum
, fs_root
, path
, iterate
, ctx
);
1894 else if (ret
!= -ENOENT
)
1897 ret
= iterate_inode_extrefs(inum
, fs_root
, path
, iterate
, ctx
);
1898 if (ret
== -ENOENT
&& found_refs
)
1905 * returns 0 if the path could be dumped (probably truncated)
1906 * returns <0 in case of an error
1908 static int inode_to_path(u64 inum
, u32 name_len
, unsigned long name_off
,
1909 struct extent_buffer
*eb
, void *ctx
)
1911 struct inode_fs_paths
*ipath
= ctx
;
1914 int i
= ipath
->fspath
->elem_cnt
;
1915 const int s_ptr
= sizeof(char *);
1918 bytes_left
= ipath
->fspath
->bytes_left
> s_ptr
?
1919 ipath
->fspath
->bytes_left
- s_ptr
: 0;
1921 fspath_min
= (char *)ipath
->fspath
->val
+ (i
+ 1) * s_ptr
;
1922 fspath
= btrfs_ref_to_path(ipath
->fs_root
, ipath
->btrfs_path
, name_len
,
1923 name_off
, eb
, inum
, fspath_min
, bytes_left
);
1925 return PTR_ERR(fspath
);
1927 if (fspath
> fspath_min
) {
1928 ipath
->fspath
->val
[i
] = (u64
)(unsigned long)fspath
;
1929 ++ipath
->fspath
->elem_cnt
;
1930 ipath
->fspath
->bytes_left
= fspath
- fspath_min
;
1932 ++ipath
->fspath
->elem_missed
;
1933 ipath
->fspath
->bytes_missing
+= fspath_min
- fspath
;
1934 ipath
->fspath
->bytes_left
= 0;
1941 * this dumps all file system paths to the inode into the ipath struct, provided
1942 * is has been created large enough. each path is zero-terminated and accessed
1943 * from ipath->fspath->val[i].
1944 * when it returns, there are ipath->fspath->elem_cnt number of paths available
1945 * in ipath->fspath->val[]. when the allocated space wasn't sufficient, the
1946 * number of missed paths in recored in ipath->fspath->elem_missed, otherwise,
1947 * it's zero. ipath->fspath->bytes_missing holds the number of bytes that would
1948 * have been needed to return all paths.
1950 int paths_from_inode(u64 inum
, struct inode_fs_paths
*ipath
)
1952 return iterate_irefs(inum
, ipath
->fs_root
, ipath
->btrfs_path
,
1953 inode_to_path
, ipath
);
1956 struct btrfs_data_container
*init_data_container(u32 total_bytes
)
1958 struct btrfs_data_container
*data
;
1961 alloc_bytes
= max_t(size_t, total_bytes
, sizeof(*data
));
1962 data
= vmalloc(alloc_bytes
);
1964 return ERR_PTR(-ENOMEM
);
1966 if (total_bytes
>= sizeof(*data
)) {
1967 data
->bytes_left
= total_bytes
- sizeof(*data
);
1968 data
->bytes_missing
= 0;
1970 data
->bytes_missing
= sizeof(*data
) - total_bytes
;
1971 data
->bytes_left
= 0;
1975 data
->elem_missed
= 0;
1981 * allocates space to return multiple file system paths for an inode.
1982 * total_bytes to allocate are passed, note that space usable for actual path
1983 * information will be total_bytes - sizeof(struct inode_fs_paths).
1984 * the returned pointer must be freed with free_ipath() in the end.
1986 struct inode_fs_paths
*init_ipath(s32 total_bytes
, struct btrfs_root
*fs_root
,
1987 struct btrfs_path
*path
)
1989 struct inode_fs_paths
*ifp
;
1990 struct btrfs_data_container
*fspath
;
1992 fspath
= init_data_container(total_bytes
);
1994 return (void *)fspath
;
1996 ifp
= kmalloc(sizeof(*ifp
), GFP_NOFS
);
1999 return ERR_PTR(-ENOMEM
);
2002 ifp
->btrfs_path
= path
;
2003 ifp
->fspath
= fspath
;
2004 ifp
->fs_root
= fs_root
;
2009 void free_ipath(struct inode_fs_paths
*ipath
)
2013 vfree(ipath
->fspath
);