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.
23 #include "transaction.h"
24 #include "delayed-ref.h"
27 struct extent_inode_elem
{
30 struct extent_inode_elem
*next
;
33 static int check_extent_in_eb(struct btrfs_key
*key
, struct extent_buffer
*eb
,
34 struct btrfs_file_extent_item
*fi
,
36 struct extent_inode_elem
**eie
)
40 struct extent_inode_elem
*e
;
42 data_offset
= btrfs_file_extent_offset(eb
, fi
);
43 data_len
= btrfs_file_extent_num_bytes(eb
, fi
);
45 if (extent_item_pos
< data_offset
||
46 extent_item_pos
>= data_offset
+ data_len
)
49 e
= kmalloc(sizeof(*e
), GFP_NOFS
);
54 e
->inum
= key
->objectid
;
55 e
->offset
= key
->offset
+ (extent_item_pos
- data_offset
);
61 static int find_extent_in_eb(struct extent_buffer
*eb
, u64 wanted_disk_byte
,
63 struct extent_inode_elem
**eie
)
67 struct btrfs_file_extent_item
*fi
;
74 * from the shared data ref, we only have the leaf but we need
75 * the key. thus, we must look into all items and see that we
76 * find one (some) with a reference to our extent item.
78 nritems
= btrfs_header_nritems(eb
);
79 for (slot
= 0; slot
< nritems
; ++slot
) {
80 btrfs_item_key_to_cpu(eb
, &key
, slot
);
81 if (key
.type
!= BTRFS_EXTENT_DATA_KEY
)
83 fi
= btrfs_item_ptr(eb
, slot
, struct btrfs_file_extent_item
);
84 extent_type
= btrfs_file_extent_type(eb
, fi
);
85 if (extent_type
== BTRFS_FILE_EXTENT_INLINE
)
87 /* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */
88 disk_byte
= btrfs_file_extent_disk_bytenr(eb
, fi
);
89 if (disk_byte
!= wanted_disk_byte
)
92 ret
= check_extent_in_eb(&key
, eb
, fi
, extent_item_pos
, eie
);
101 * this structure records all encountered refs on the way up to the root
103 struct __prelim_ref
{
104 struct list_head list
;
106 struct btrfs_key key_for_search
;
109 struct extent_inode_elem
*inode_list
;
111 u64 wanted_disk_byte
;
115 * the rules for all callers of this function are:
116 * - obtaining the parent is the goal
117 * - if you add a key, you must know that it is a correct key
118 * - if you cannot add the parent or a correct key, then we will look into the
119 * block later to set a correct key
123 * backref type | shared | indirect | shared | indirect
124 * information | tree | tree | data | data
125 * --------------------+--------+----------+--------+----------
126 * parent logical | y | - | - | -
127 * key to resolve | - | y | y | y
128 * tree block logical | - | - | - | -
129 * root for resolving | y | y | y | y
131 * - column 1: we've the parent -> done
132 * - column 2, 3, 4: we use the key to find the parent
134 * on disk refs (inline or keyed)
135 * ==============================
136 * backref type | shared | indirect | shared | indirect
137 * information | tree | tree | data | data
138 * --------------------+--------+----------+--------+----------
139 * parent logical | y | - | y | -
140 * key to resolve | - | - | - | y
141 * tree block logical | y | y | y | y
142 * root for resolving | - | y | y | y
144 * - column 1, 3: we've the parent -> done
145 * - column 2: we take the first key from the block to find the parent
146 * (see __add_missing_keys)
147 * - column 4: we use the key to find the parent
149 * additional information that's available but not required to find the parent
150 * block might help in merging entries to gain some speed.
153 static int __add_prelim_ref(struct list_head
*head
, u64 root_id
,
154 struct btrfs_key
*key
, int level
,
155 u64 parent
, u64 wanted_disk_byte
, int count
)
157 struct __prelim_ref
*ref
;
159 /* in case we're adding delayed refs, we're holding the refs spinlock */
160 ref
= kmalloc(sizeof(*ref
), GFP_ATOMIC
);
164 ref
->root_id
= root_id
;
166 ref
->key_for_search
= *key
;
168 memset(&ref
->key_for_search
, 0, sizeof(ref
->key_for_search
));
170 ref
->inode_list
= NULL
;
173 ref
->parent
= parent
;
174 ref
->wanted_disk_byte
= wanted_disk_byte
;
175 list_add_tail(&ref
->list
, head
);
180 static int add_all_parents(struct btrfs_root
*root
, struct btrfs_path
*path
,
181 struct ulist
*parents
, int level
,
182 struct btrfs_key
*key_for_search
, u64 time_seq
,
183 u64 wanted_disk_byte
,
184 const u64
*extent_item_pos
)
188 struct extent_buffer
*eb
;
189 struct btrfs_key key
;
190 struct btrfs_file_extent_item
*fi
;
191 struct extent_inode_elem
*eie
= NULL
;
195 eb
= path
->nodes
[level
];
196 ret
= ulist_add(parents
, eb
->start
, 0, GFP_NOFS
);
203 * We normally enter this function with the path already pointing to
204 * the first item to check. But sometimes, we may enter it with
205 * slot==nritems. In that case, go to the next leaf before we continue.
207 if (path
->slots
[0] >= btrfs_header_nritems(path
->nodes
[0]))
208 ret
= btrfs_next_old_leaf(root
, path
, time_seq
);
212 slot
= path
->slots
[0];
214 btrfs_item_key_to_cpu(eb
, &key
, slot
);
216 if (key
.objectid
!= key_for_search
->objectid
||
217 key
.type
!= BTRFS_EXTENT_DATA_KEY
)
220 fi
= btrfs_item_ptr(eb
, slot
, struct btrfs_file_extent_item
);
221 disk_byte
= btrfs_file_extent_disk_bytenr(eb
, fi
);
223 if (disk_byte
== wanted_disk_byte
) {
225 if (extent_item_pos
) {
226 ret
= check_extent_in_eb(&key
, eb
, fi
,
233 ret
= ulist_add(parents
, eb
->start
,
234 (unsigned long)eie
, GFP_NOFS
);
237 if (!extent_item_pos
) {
238 ret
= btrfs_next_old_leaf(root
, path
,
244 ret
= btrfs_next_old_item(root
, path
, time_seq
);
253 * resolve an indirect backref in the form (root_id, key, level)
254 * to a logical address
256 static int __resolve_indirect_ref(struct btrfs_fs_info
*fs_info
,
257 int search_commit_root
,
259 struct __prelim_ref
*ref
,
260 struct ulist
*parents
,
261 const u64
*extent_item_pos
)
263 struct btrfs_path
*path
;
264 struct btrfs_root
*root
;
265 struct btrfs_key root_key
;
266 struct extent_buffer
*eb
;
269 int level
= ref
->level
;
271 path
= btrfs_alloc_path();
274 path
->search_commit_root
= !!search_commit_root
;
276 root_key
.objectid
= ref
->root_id
;
277 root_key
.type
= BTRFS_ROOT_ITEM_KEY
;
278 root_key
.offset
= (u64
)-1;
279 root
= btrfs_read_fs_root_no_name(fs_info
, &root_key
);
286 root_level
= btrfs_header_level(root
->node
);
289 if (root_level
+ 1 == level
)
292 path
->lowest_level
= level
;
293 ret
= btrfs_search_old_slot(root
, &ref
->key_for_search
, path
, time_seq
);
294 pr_debug("search slot in root %llu (level %d, ref count %d) returned "
295 "%d for key (%llu %u %llu)\n",
296 (unsigned long long)ref
->root_id
, level
, ref
->count
, ret
,
297 (unsigned long long)ref
->key_for_search
.objectid
,
298 ref
->key_for_search
.type
,
299 (unsigned long long)ref
->key_for_search
.offset
);
303 eb
= path
->nodes
[level
];
311 eb
= path
->nodes
[level
];
314 ret
= add_all_parents(root
, path
, parents
, level
, &ref
->key_for_search
,
315 time_seq
, ref
->wanted_disk_byte
,
318 btrfs_free_path(path
);
323 * resolve all indirect backrefs from the list
325 static int __resolve_indirect_refs(struct btrfs_fs_info
*fs_info
,
326 int search_commit_root
, u64 time_seq
,
327 struct list_head
*head
,
328 const u64
*extent_item_pos
)
332 struct __prelim_ref
*ref
;
333 struct __prelim_ref
*ref_safe
;
334 struct __prelim_ref
*new_ref
;
335 struct ulist
*parents
;
336 struct ulist_node
*node
;
337 struct ulist_iterator uiter
;
339 parents
= ulist_alloc(GFP_NOFS
);
344 * _safe allows us to insert directly after the current item without
345 * iterating over the newly inserted items.
346 * we're also allowed to re-assign ref during iteration.
348 list_for_each_entry_safe(ref
, ref_safe
, head
, list
) {
349 if (ref
->parent
) /* already direct */
353 err
= __resolve_indirect_ref(fs_info
, search_commit_root
,
354 time_seq
, ref
, parents
,
362 /* we put the first parent into the ref at hand */
363 ULIST_ITER_INIT(&uiter
);
364 node
= ulist_next(parents
, &uiter
);
365 ref
->parent
= node
? node
->val
: 0;
367 node
? (struct extent_inode_elem
*)node
->aux
: 0;
369 /* additional parents require new refs being added here */
370 while ((node
= ulist_next(parents
, &uiter
))) {
371 new_ref
= kmalloc(sizeof(*new_ref
), GFP_NOFS
);
376 memcpy(new_ref
, ref
, sizeof(*ref
));
377 new_ref
->parent
= node
->val
;
378 new_ref
->inode_list
=
379 (struct extent_inode_elem
*)node
->aux
;
380 list_add(&new_ref
->list
, &ref
->list
);
382 ulist_reinit(parents
);
389 static inline int ref_for_same_block(struct __prelim_ref
*ref1
,
390 struct __prelim_ref
*ref2
)
392 if (ref1
->level
!= ref2
->level
)
394 if (ref1
->root_id
!= ref2
->root_id
)
396 if (ref1
->key_for_search
.type
!= ref2
->key_for_search
.type
)
398 if (ref1
->key_for_search
.objectid
!= ref2
->key_for_search
.objectid
)
400 if (ref1
->key_for_search
.offset
!= ref2
->key_for_search
.offset
)
402 if (ref1
->parent
!= ref2
->parent
)
409 * read tree blocks and add keys where required.
411 static int __add_missing_keys(struct btrfs_fs_info
*fs_info
,
412 struct list_head
*head
)
414 struct list_head
*pos
;
415 struct extent_buffer
*eb
;
417 list_for_each(pos
, head
) {
418 struct __prelim_ref
*ref
;
419 ref
= list_entry(pos
, struct __prelim_ref
, list
);
423 if (ref
->key_for_search
.type
)
425 BUG_ON(!ref
->wanted_disk_byte
);
426 eb
= read_tree_block(fs_info
->tree_root
, ref
->wanted_disk_byte
,
427 fs_info
->tree_root
->leafsize
, 0);
429 btrfs_tree_read_lock(eb
);
430 if (btrfs_header_level(eb
) == 0)
431 btrfs_item_key_to_cpu(eb
, &ref
->key_for_search
, 0);
433 btrfs_node_key_to_cpu(eb
, &ref
->key_for_search
, 0);
434 btrfs_tree_read_unlock(eb
);
435 free_extent_buffer(eb
);
441 * merge two lists of backrefs and adjust counts accordingly
443 * mode = 1: merge identical keys, if key is set
444 * FIXME: if we add more keys in __add_prelim_ref, we can merge more here.
445 * additionally, we could even add a key range for the blocks we
446 * looked into to merge even more (-> replace unresolved refs by those
448 * mode = 2: merge identical parents
450 static int __merge_refs(struct list_head
*head
, int mode
)
452 struct list_head
*pos1
;
454 list_for_each(pos1
, head
) {
455 struct list_head
*n2
;
456 struct list_head
*pos2
;
457 struct __prelim_ref
*ref1
;
459 ref1
= list_entry(pos1
, struct __prelim_ref
, list
);
461 for (pos2
= pos1
->next
, n2
= pos2
->next
; pos2
!= head
;
462 pos2
= n2
, n2
= pos2
->next
) {
463 struct __prelim_ref
*ref2
;
464 struct __prelim_ref
*xchg
;
466 ref2
= list_entry(pos2
, struct __prelim_ref
, list
);
469 if (!ref_for_same_block(ref1
, ref2
))
471 if (!ref1
->parent
&& ref2
->parent
) {
476 ref1
->count
+= ref2
->count
;
478 if (ref1
->parent
!= ref2
->parent
)
480 ref1
->count
+= ref2
->count
;
482 list_del(&ref2
->list
);
491 * add all currently queued delayed refs from this head whose seq nr is
492 * smaller or equal that seq to the list
494 static int __add_delayed_refs(struct btrfs_delayed_ref_head
*head
, u64 seq
,
495 struct list_head
*prefs
)
497 struct btrfs_delayed_extent_op
*extent_op
= head
->extent_op
;
498 struct rb_node
*n
= &head
->node
.rb_node
;
499 struct btrfs_key key
;
500 struct btrfs_key op_key
= {0};
504 if (extent_op
&& extent_op
->update_key
)
505 btrfs_disk_key_to_cpu(&op_key
, &extent_op
->key
);
507 while ((n
= rb_prev(n
))) {
508 struct btrfs_delayed_ref_node
*node
;
509 node
= rb_entry(n
, struct btrfs_delayed_ref_node
,
511 if (node
->bytenr
!= head
->node
.bytenr
)
513 WARN_ON(node
->is_head
);
518 switch (node
->action
) {
519 case BTRFS_ADD_DELAYED_EXTENT
:
520 case BTRFS_UPDATE_DELAYED_HEAD
:
523 case BTRFS_ADD_DELAYED_REF
:
526 case BTRFS_DROP_DELAYED_REF
:
532 switch (node
->type
) {
533 case BTRFS_TREE_BLOCK_REF_KEY
: {
534 struct btrfs_delayed_tree_ref
*ref
;
536 ref
= btrfs_delayed_node_to_tree_ref(node
);
537 ret
= __add_prelim_ref(prefs
, ref
->root
, &op_key
,
538 ref
->level
+ 1, 0, node
->bytenr
,
539 node
->ref_mod
* sgn
);
542 case BTRFS_SHARED_BLOCK_REF_KEY
: {
543 struct btrfs_delayed_tree_ref
*ref
;
545 ref
= btrfs_delayed_node_to_tree_ref(node
);
546 ret
= __add_prelim_ref(prefs
, ref
->root
, NULL
,
547 ref
->level
+ 1, ref
->parent
,
549 node
->ref_mod
* sgn
);
552 case BTRFS_EXTENT_DATA_REF_KEY
: {
553 struct btrfs_delayed_data_ref
*ref
;
554 ref
= btrfs_delayed_node_to_data_ref(node
);
556 key
.objectid
= ref
->objectid
;
557 key
.type
= BTRFS_EXTENT_DATA_KEY
;
558 key
.offset
= ref
->offset
;
559 ret
= __add_prelim_ref(prefs
, ref
->root
, &key
, 0, 0,
561 node
->ref_mod
* sgn
);
564 case BTRFS_SHARED_DATA_REF_KEY
: {
565 struct btrfs_delayed_data_ref
*ref
;
567 ref
= btrfs_delayed_node_to_data_ref(node
);
569 key
.objectid
= ref
->objectid
;
570 key
.type
= BTRFS_EXTENT_DATA_KEY
;
571 key
.offset
= ref
->offset
;
572 ret
= __add_prelim_ref(prefs
, ref
->root
, &key
, 0,
573 ref
->parent
, node
->bytenr
,
574 node
->ref_mod
* sgn
);
587 * add all inline backrefs for bytenr to the list
589 static int __add_inline_refs(struct btrfs_fs_info
*fs_info
,
590 struct btrfs_path
*path
, u64 bytenr
,
591 int *info_level
, struct list_head
*prefs
)
595 struct extent_buffer
*leaf
;
596 struct btrfs_key key
;
599 struct btrfs_extent_item
*ei
;
604 * enumerate all inline refs
606 leaf
= path
->nodes
[0];
607 slot
= path
->slots
[0];
609 item_size
= btrfs_item_size_nr(leaf
, slot
);
610 BUG_ON(item_size
< sizeof(*ei
));
612 ei
= btrfs_item_ptr(leaf
, slot
, struct btrfs_extent_item
);
613 flags
= btrfs_extent_flags(leaf
, ei
);
615 ptr
= (unsigned long)(ei
+ 1);
616 end
= (unsigned long)ei
+ item_size
;
618 if (flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
) {
619 struct btrfs_tree_block_info
*info
;
621 info
= (struct btrfs_tree_block_info
*)ptr
;
622 *info_level
= btrfs_tree_block_level(leaf
, info
);
623 ptr
+= sizeof(struct btrfs_tree_block_info
);
626 BUG_ON(!(flags
& BTRFS_EXTENT_FLAG_DATA
));
630 struct btrfs_extent_inline_ref
*iref
;
634 iref
= (struct btrfs_extent_inline_ref
*)ptr
;
635 type
= btrfs_extent_inline_ref_type(leaf
, iref
);
636 offset
= btrfs_extent_inline_ref_offset(leaf
, iref
);
639 case BTRFS_SHARED_BLOCK_REF_KEY
:
640 ret
= __add_prelim_ref(prefs
, 0, NULL
,
641 *info_level
+ 1, offset
,
644 case BTRFS_SHARED_DATA_REF_KEY
: {
645 struct btrfs_shared_data_ref
*sdref
;
648 sdref
= (struct btrfs_shared_data_ref
*)(iref
+ 1);
649 count
= btrfs_shared_data_ref_count(leaf
, sdref
);
650 ret
= __add_prelim_ref(prefs
, 0, NULL
, 0, offset
,
654 case BTRFS_TREE_BLOCK_REF_KEY
:
655 ret
= __add_prelim_ref(prefs
, offset
, NULL
,
659 case BTRFS_EXTENT_DATA_REF_KEY
: {
660 struct btrfs_extent_data_ref
*dref
;
664 dref
= (struct btrfs_extent_data_ref
*)(&iref
->offset
);
665 count
= btrfs_extent_data_ref_count(leaf
, dref
);
666 key
.objectid
= btrfs_extent_data_ref_objectid(leaf
,
668 key
.type
= BTRFS_EXTENT_DATA_KEY
;
669 key
.offset
= btrfs_extent_data_ref_offset(leaf
, dref
);
670 root
= btrfs_extent_data_ref_root(leaf
, dref
);
671 ret
= __add_prelim_ref(prefs
, root
, &key
, 0, 0,
679 ptr
+= btrfs_extent_inline_ref_size(type
);
686 * add all non-inline backrefs for bytenr to the list
688 static int __add_keyed_refs(struct btrfs_fs_info
*fs_info
,
689 struct btrfs_path
*path
, u64 bytenr
,
690 int info_level
, struct list_head
*prefs
)
692 struct btrfs_root
*extent_root
= fs_info
->extent_root
;
695 struct extent_buffer
*leaf
;
696 struct btrfs_key key
;
699 ret
= btrfs_next_item(extent_root
, path
);
707 slot
= path
->slots
[0];
708 leaf
= path
->nodes
[0];
709 btrfs_item_key_to_cpu(leaf
, &key
, slot
);
711 if (key
.objectid
!= bytenr
)
713 if (key
.type
< BTRFS_TREE_BLOCK_REF_KEY
)
715 if (key
.type
> BTRFS_SHARED_DATA_REF_KEY
)
719 case BTRFS_SHARED_BLOCK_REF_KEY
:
720 ret
= __add_prelim_ref(prefs
, 0, NULL
,
721 info_level
+ 1, key
.offset
,
724 case BTRFS_SHARED_DATA_REF_KEY
: {
725 struct btrfs_shared_data_ref
*sdref
;
728 sdref
= btrfs_item_ptr(leaf
, slot
,
729 struct btrfs_shared_data_ref
);
730 count
= btrfs_shared_data_ref_count(leaf
, sdref
);
731 ret
= __add_prelim_ref(prefs
, 0, NULL
, 0, key
.offset
,
735 case BTRFS_TREE_BLOCK_REF_KEY
:
736 ret
= __add_prelim_ref(prefs
, key
.offset
, NULL
,
740 case BTRFS_EXTENT_DATA_REF_KEY
: {
741 struct btrfs_extent_data_ref
*dref
;
745 dref
= btrfs_item_ptr(leaf
, slot
,
746 struct btrfs_extent_data_ref
);
747 count
= btrfs_extent_data_ref_count(leaf
, dref
);
748 key
.objectid
= btrfs_extent_data_ref_objectid(leaf
,
750 key
.type
= BTRFS_EXTENT_DATA_KEY
;
751 key
.offset
= btrfs_extent_data_ref_offset(leaf
, dref
);
752 root
= btrfs_extent_data_ref_root(leaf
, dref
);
753 ret
= __add_prelim_ref(prefs
, root
, &key
, 0, 0,
767 * this adds all existing backrefs (inline backrefs, backrefs and delayed
768 * refs) for the given bytenr to the refs list, merges duplicates and resolves
769 * indirect refs to their parent bytenr.
770 * When roots are found, they're added to the roots list
772 * FIXME some caching might speed things up
774 static int find_parent_nodes(struct btrfs_trans_handle
*trans
,
775 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
776 u64 time_seq
, struct ulist
*refs
,
777 struct ulist
*roots
, const u64
*extent_item_pos
)
779 struct btrfs_key key
;
780 struct btrfs_path
*path
;
781 struct btrfs_delayed_ref_root
*delayed_refs
= NULL
;
782 struct btrfs_delayed_ref_head
*head
;
785 int search_commit_root
= (trans
== BTRFS_BACKREF_SEARCH_COMMIT_ROOT
);
786 struct list_head prefs_delayed
;
787 struct list_head prefs
;
788 struct __prelim_ref
*ref
;
790 INIT_LIST_HEAD(&prefs
);
791 INIT_LIST_HEAD(&prefs_delayed
);
793 key
.objectid
= bytenr
;
794 key
.type
= BTRFS_EXTENT_ITEM_KEY
;
795 key
.offset
= (u64
)-1;
797 path
= btrfs_alloc_path();
800 path
->search_commit_root
= !!search_commit_root
;
803 * grab both a lock on the path and a lock on the delayed ref head.
804 * We need both to get a consistent picture of how the refs look
805 * at a specified point in time
810 ret
= btrfs_search_slot(trans
, fs_info
->extent_root
, &key
, path
, 0, 0);
815 if (trans
!= BTRFS_BACKREF_SEARCH_COMMIT_ROOT
) {
817 * look if there are updates for this ref queued and lock the
820 delayed_refs
= &trans
->transaction
->delayed_refs
;
821 spin_lock(&delayed_refs
->lock
);
822 head
= btrfs_find_delayed_ref_head(trans
, bytenr
);
824 if (!mutex_trylock(&head
->mutex
)) {
825 atomic_inc(&head
->node
.refs
);
826 spin_unlock(&delayed_refs
->lock
);
828 btrfs_release_path(path
);
831 * Mutex was contended, block until it's
832 * released and try again
834 mutex_lock(&head
->mutex
);
835 mutex_unlock(&head
->mutex
);
836 btrfs_put_delayed_ref(&head
->node
);
839 ret
= __add_delayed_refs(head
, time_seq
,
841 mutex_unlock(&head
->mutex
);
843 spin_unlock(&delayed_refs
->lock
);
847 spin_unlock(&delayed_refs
->lock
);
850 if (path
->slots
[0]) {
851 struct extent_buffer
*leaf
;
855 leaf
= path
->nodes
[0];
856 slot
= path
->slots
[0];
857 btrfs_item_key_to_cpu(leaf
, &key
, slot
);
858 if (key
.objectid
== bytenr
&&
859 key
.type
== BTRFS_EXTENT_ITEM_KEY
) {
860 ret
= __add_inline_refs(fs_info
, path
, bytenr
,
861 &info_level
, &prefs
);
864 ret
= __add_keyed_refs(fs_info
, path
, bytenr
,
870 btrfs_release_path(path
);
872 list_splice_init(&prefs_delayed
, &prefs
);
874 ret
= __add_missing_keys(fs_info
, &prefs
);
878 ret
= __merge_refs(&prefs
, 1);
882 ret
= __resolve_indirect_refs(fs_info
, search_commit_root
, time_seq
,
883 &prefs
, extent_item_pos
);
887 ret
= __merge_refs(&prefs
, 2);
891 while (!list_empty(&prefs
)) {
892 ref
= list_first_entry(&prefs
, struct __prelim_ref
, list
);
893 list_del(&ref
->list
);
896 if (ref
->count
&& ref
->root_id
&& ref
->parent
== 0) {
897 /* no parent == root of tree */
898 ret
= ulist_add(roots
, ref
->root_id
, 0, GFP_NOFS
);
901 if (ref
->count
&& ref
->parent
) {
902 struct extent_inode_elem
*eie
= NULL
;
903 if (extent_item_pos
&& !ref
->inode_list
) {
905 struct extent_buffer
*eb
;
906 bsz
= btrfs_level_size(fs_info
->extent_root
,
908 eb
= read_tree_block(fs_info
->extent_root
,
909 ref
->parent
, bsz
, 0);
911 ret
= find_extent_in_eb(eb
, bytenr
,
912 *extent_item_pos
, &eie
);
913 ref
->inode_list
= eie
;
914 free_extent_buffer(eb
);
916 ret
= ulist_add_merge(refs
, ref
->parent
,
917 (unsigned long)ref
->inode_list
,
918 (unsigned long *)&eie
, GFP_NOFS
);
919 if (!ret
&& extent_item_pos
) {
921 * we've recorded that parent, so we must extend
922 * its inode list here
927 eie
->next
= ref
->inode_list
;
935 btrfs_free_path(path
);
936 while (!list_empty(&prefs
)) {
937 ref
= list_first_entry(&prefs
, struct __prelim_ref
, list
);
938 list_del(&ref
->list
);
941 while (!list_empty(&prefs_delayed
)) {
942 ref
= list_first_entry(&prefs_delayed
, struct __prelim_ref
,
944 list_del(&ref
->list
);
951 static void free_leaf_list(struct ulist
*blocks
)
953 struct ulist_node
*node
= NULL
;
954 struct extent_inode_elem
*eie
;
955 struct extent_inode_elem
*eie_next
;
956 struct ulist_iterator uiter
;
958 ULIST_ITER_INIT(&uiter
);
959 while ((node
= ulist_next(blocks
, &uiter
))) {
962 eie
= (struct extent_inode_elem
*)node
->aux
;
963 for (; eie
; eie
= eie_next
) {
964 eie_next
= eie
->next
;
974 * Finds all leafs with a reference to the specified combination of bytenr and
975 * offset. key_list_head will point to a list of corresponding keys (caller must
976 * free each list element). The leafs will be stored in the leafs ulist, which
977 * must be freed with ulist_free.
979 * returns 0 on success, <0 on error
981 static int btrfs_find_all_leafs(struct btrfs_trans_handle
*trans
,
982 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
983 u64 time_seq
, struct ulist
**leafs
,
984 const u64
*extent_item_pos
)
989 tmp
= ulist_alloc(GFP_NOFS
);
992 *leafs
= ulist_alloc(GFP_NOFS
);
998 ret
= find_parent_nodes(trans
, fs_info
, bytenr
,
999 time_seq
, *leafs
, tmp
, extent_item_pos
);
1002 if (ret
< 0 && ret
!= -ENOENT
) {
1003 free_leaf_list(*leafs
);
1011 * walk all backrefs for a given extent to find all roots that reference this
1012 * extent. Walking a backref means finding all extents that reference this
1013 * extent and in turn walk the backrefs of those, too. Naturally this is a
1014 * recursive process, but here it is implemented in an iterative fashion: We
1015 * find all referencing extents for the extent in question and put them on a
1016 * list. In turn, we find all referencing extents for those, further appending
1017 * to the list. The way we iterate the list allows adding more elements after
1018 * the current while iterating. The process stops when we reach the end of the
1019 * list. Found roots are added to the roots list.
1021 * returns 0 on success, < 0 on error.
1023 int btrfs_find_all_roots(struct btrfs_trans_handle
*trans
,
1024 struct btrfs_fs_info
*fs_info
, u64 bytenr
,
1025 u64 time_seq
, struct ulist
**roots
)
1028 struct ulist_node
*node
= NULL
;
1029 struct ulist_iterator uiter
;
1032 tmp
= ulist_alloc(GFP_NOFS
);
1035 *roots
= ulist_alloc(GFP_NOFS
);
1041 ULIST_ITER_INIT(&uiter
);
1043 ret
= find_parent_nodes(trans
, fs_info
, bytenr
,
1044 time_seq
, tmp
, *roots
, NULL
);
1045 if (ret
< 0 && ret
!= -ENOENT
) {
1050 node
= ulist_next(tmp
, &uiter
);
1061 static int __inode_info(u64 inum
, u64 ioff
, u8 key_type
,
1062 struct btrfs_root
*fs_root
, struct btrfs_path
*path
,
1063 struct btrfs_key
*found_key
)
1066 struct btrfs_key key
;
1067 struct extent_buffer
*eb
;
1069 key
.type
= key_type
;
1070 key
.objectid
= inum
;
1073 ret
= btrfs_search_slot(NULL
, fs_root
, &key
, path
, 0, 0);
1077 eb
= path
->nodes
[0];
1078 if (ret
&& path
->slots
[0] >= btrfs_header_nritems(eb
)) {
1079 ret
= btrfs_next_leaf(fs_root
, path
);
1082 eb
= path
->nodes
[0];
1085 btrfs_item_key_to_cpu(eb
, found_key
, path
->slots
[0]);
1086 if (found_key
->type
!= key
.type
|| found_key
->objectid
!= key
.objectid
)
1093 * this makes the path point to (inum INODE_ITEM ioff)
1095 int inode_item_info(u64 inum
, u64 ioff
, struct btrfs_root
*fs_root
,
1096 struct btrfs_path
*path
)
1098 struct btrfs_key key
;
1099 return __inode_info(inum
, ioff
, BTRFS_INODE_ITEM_KEY
, fs_root
, path
,
1103 static int inode_ref_info(u64 inum
, u64 ioff
, struct btrfs_root
*fs_root
,
1104 struct btrfs_path
*path
,
1105 struct btrfs_key
*found_key
)
1107 return __inode_info(inum
, ioff
, BTRFS_INODE_REF_KEY
, fs_root
, path
,
1112 * this iterates to turn a btrfs_inode_ref into a full filesystem path. elements
1113 * of the path are separated by '/' and the path is guaranteed to be
1114 * 0-terminated. the path is only given within the current file system.
1115 * Therefore, it never starts with a '/'. the caller is responsible to provide
1116 * "size" bytes in "dest". the dest buffer will be filled backwards. finally,
1117 * the start point of the resulting string is returned. this pointer is within
1119 * in case the path buffer would overflow, the pointer is decremented further
1120 * as if output was written to the buffer, though no more output is actually
1121 * generated. that way, the caller can determine how much space would be
1122 * required for the path to fit into the buffer. in that case, the returned
1123 * value will be smaller than dest. callers must check this!
1125 char *btrfs_iref_to_path(struct btrfs_root
*fs_root
, struct btrfs_path
*path
,
1126 struct btrfs_inode_ref
*iref
,
1127 struct extent_buffer
*eb_in
, u64 parent
,
1128 char *dest
, u32 size
)
1134 s64 bytes_left
= size
- 1;
1135 struct extent_buffer
*eb
= eb_in
;
1136 struct btrfs_key found_key
;
1137 int leave_spinning
= path
->leave_spinning
;
1139 if (bytes_left
>= 0)
1140 dest
[bytes_left
] = '\0';
1142 path
->leave_spinning
= 1;
1144 len
= btrfs_inode_ref_name_len(eb
, iref
);
1146 if (bytes_left
>= 0)
1147 read_extent_buffer(eb
, dest
+ bytes_left
,
1148 (unsigned long)(iref
+ 1), len
);
1150 btrfs_tree_read_unlock_blocking(eb
);
1151 free_extent_buffer(eb
);
1153 ret
= inode_ref_info(parent
, 0, fs_root
, path
, &found_key
);
1158 next_inum
= found_key
.offset
;
1160 /* regular exit ahead */
1161 if (parent
== next_inum
)
1164 slot
= path
->slots
[0];
1165 eb
= path
->nodes
[0];
1166 /* make sure we can use eb after releasing the path */
1168 atomic_inc(&eb
->refs
);
1169 btrfs_tree_read_lock(eb
);
1170 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1172 btrfs_release_path(path
);
1174 iref
= btrfs_item_ptr(eb
, slot
, struct btrfs_inode_ref
);
1177 if (bytes_left
>= 0)
1178 dest
[bytes_left
] = '/';
1181 btrfs_release_path(path
);
1182 path
->leave_spinning
= leave_spinning
;
1185 return ERR_PTR(ret
);
1187 return dest
+ bytes_left
;
1191 * this makes the path point to (logical EXTENT_ITEM *)
1192 * returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for
1193 * tree blocks and <0 on error.
1195 int extent_from_logical(struct btrfs_fs_info
*fs_info
, u64 logical
,
1196 struct btrfs_path
*path
, struct btrfs_key
*found_key
)
1201 struct extent_buffer
*eb
;
1202 struct btrfs_extent_item
*ei
;
1203 struct btrfs_key key
;
1205 key
.type
= BTRFS_EXTENT_ITEM_KEY
;
1206 key
.objectid
= logical
;
1207 key
.offset
= (u64
)-1;
1209 ret
= btrfs_search_slot(NULL
, fs_info
->extent_root
, &key
, path
, 0, 0);
1212 ret
= btrfs_previous_item(fs_info
->extent_root
, path
,
1213 0, BTRFS_EXTENT_ITEM_KEY
);
1217 btrfs_item_key_to_cpu(path
->nodes
[0], found_key
, path
->slots
[0]);
1218 if (found_key
->type
!= BTRFS_EXTENT_ITEM_KEY
||
1219 found_key
->objectid
> logical
||
1220 found_key
->objectid
+ found_key
->offset
<= logical
) {
1221 pr_debug("logical %llu is not within any extent\n",
1222 (unsigned long long)logical
);
1226 eb
= path
->nodes
[0];
1227 item_size
= btrfs_item_size_nr(eb
, path
->slots
[0]);
1228 BUG_ON(item_size
< sizeof(*ei
));
1230 ei
= btrfs_item_ptr(eb
, path
->slots
[0], struct btrfs_extent_item
);
1231 flags
= btrfs_extent_flags(eb
, ei
);
1233 pr_debug("logical %llu is at position %llu within the extent (%llu "
1234 "EXTENT_ITEM %llu) flags %#llx size %u\n",
1235 (unsigned long long)logical
,
1236 (unsigned long long)(logical
- found_key
->objectid
),
1237 (unsigned long long)found_key
->objectid
,
1238 (unsigned long long)found_key
->offset
,
1239 (unsigned long long)flags
, item_size
);
1240 if (flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
)
1241 return BTRFS_EXTENT_FLAG_TREE_BLOCK
;
1242 if (flags
& BTRFS_EXTENT_FLAG_DATA
)
1243 return BTRFS_EXTENT_FLAG_DATA
;
1249 * helper function to iterate extent inline refs. ptr must point to a 0 value
1250 * for the first call and may be modified. it is used to track state.
1251 * if more refs exist, 0 is returned and the next call to
1252 * __get_extent_inline_ref must pass the modified ptr parameter to get the
1253 * next ref. after the last ref was processed, 1 is returned.
1254 * returns <0 on error
1256 static int __get_extent_inline_ref(unsigned long *ptr
, struct extent_buffer
*eb
,
1257 struct btrfs_extent_item
*ei
, u32 item_size
,
1258 struct btrfs_extent_inline_ref
**out_eiref
,
1263 struct btrfs_tree_block_info
*info
;
1267 flags
= btrfs_extent_flags(eb
, ei
);
1268 if (flags
& BTRFS_EXTENT_FLAG_TREE_BLOCK
) {
1269 info
= (struct btrfs_tree_block_info
*)(ei
+ 1);
1271 (struct btrfs_extent_inline_ref
*)(info
+ 1);
1273 *out_eiref
= (struct btrfs_extent_inline_ref
*)(ei
+ 1);
1275 *ptr
= (unsigned long)*out_eiref
;
1276 if ((void *)*ptr
>= (void *)ei
+ item_size
)
1280 end
= (unsigned long)ei
+ item_size
;
1281 *out_eiref
= (struct btrfs_extent_inline_ref
*)*ptr
;
1282 *out_type
= btrfs_extent_inline_ref_type(eb
, *out_eiref
);
1284 *ptr
+= btrfs_extent_inline_ref_size(*out_type
);
1285 WARN_ON(*ptr
> end
);
1287 return 1; /* last */
1293 * reads the tree block backref for an extent. tree level and root are returned
1294 * through out_level and out_root. ptr must point to a 0 value for the first
1295 * call and may be modified (see __get_extent_inline_ref comment).
1296 * returns 0 if data was provided, 1 if there was no more data to provide or
1299 int tree_backref_for_extent(unsigned long *ptr
, struct extent_buffer
*eb
,
1300 struct btrfs_extent_item
*ei
, u32 item_size
,
1301 u64
*out_root
, u8
*out_level
)
1305 struct btrfs_tree_block_info
*info
;
1306 struct btrfs_extent_inline_ref
*eiref
;
1308 if (*ptr
== (unsigned long)-1)
1312 ret
= __get_extent_inline_ref(ptr
, eb
, ei
, item_size
,
1317 if (type
== BTRFS_TREE_BLOCK_REF_KEY
||
1318 type
== BTRFS_SHARED_BLOCK_REF_KEY
)
1325 /* we can treat both ref types equally here */
1326 info
= (struct btrfs_tree_block_info
*)(ei
+ 1);
1327 *out_root
= btrfs_extent_inline_ref_offset(eb
, eiref
);
1328 *out_level
= btrfs_tree_block_level(eb
, info
);
1331 *ptr
= (unsigned long)-1;
1336 static int iterate_leaf_refs(struct extent_inode_elem
*inode_list
,
1337 u64 root
, u64 extent_item_objectid
,
1338 iterate_extent_inodes_t
*iterate
, void *ctx
)
1340 struct extent_inode_elem
*eie
;
1343 for (eie
= inode_list
; eie
; eie
= eie
->next
) {
1344 pr_debug("ref for %llu resolved, key (%llu EXTEND_DATA %llu), "
1345 "root %llu\n", extent_item_objectid
,
1346 eie
->inum
, eie
->offset
, root
);
1347 ret
= iterate(eie
->inum
, eie
->offset
, root
, ctx
);
1349 pr_debug("stopping iteration for %llu due to ret=%d\n",
1350 extent_item_objectid
, ret
);
1359 * calls iterate() for every inode that references the extent identified by
1360 * the given parameters.
1361 * when the iterator function returns a non-zero value, iteration stops.
1363 int iterate_extent_inodes(struct btrfs_fs_info
*fs_info
,
1364 u64 extent_item_objectid
, u64 extent_item_pos
,
1365 int search_commit_root
,
1366 iterate_extent_inodes_t
*iterate
, void *ctx
)
1369 struct list_head data_refs
= LIST_HEAD_INIT(data_refs
);
1370 struct list_head shared_refs
= LIST_HEAD_INIT(shared_refs
);
1371 struct btrfs_trans_handle
*trans
;
1372 struct ulist
*refs
= NULL
;
1373 struct ulist
*roots
= NULL
;
1374 struct ulist_node
*ref_node
= NULL
;
1375 struct ulist_node
*root_node
= NULL
;
1376 struct seq_list tree_mod_seq_elem
= {};
1377 struct ulist_iterator ref_uiter
;
1378 struct ulist_iterator root_uiter
;
1380 pr_debug("resolving all inodes for extent %llu\n",
1381 extent_item_objectid
);
1383 if (search_commit_root
) {
1384 trans
= BTRFS_BACKREF_SEARCH_COMMIT_ROOT
;
1386 trans
= btrfs_join_transaction(fs_info
->extent_root
);
1388 return PTR_ERR(trans
);
1389 btrfs_get_tree_mod_seq(fs_info
, &tree_mod_seq_elem
);
1392 ret
= btrfs_find_all_leafs(trans
, fs_info
, extent_item_objectid
,
1393 tree_mod_seq_elem
.seq
, &refs
,
1398 ULIST_ITER_INIT(&ref_uiter
);
1399 while (!ret
&& (ref_node
= ulist_next(refs
, &ref_uiter
))) {
1400 ret
= btrfs_find_all_roots(trans
, fs_info
, ref_node
->val
,
1401 tree_mod_seq_elem
.seq
, &roots
);
1404 ULIST_ITER_INIT(&root_uiter
);
1405 while (!ret
&& (root_node
= ulist_next(roots
, &root_uiter
))) {
1406 pr_debug("root %llu references leaf %llu, data list "
1407 "%#lx\n", root_node
->val
, ref_node
->val
,
1409 ret
= iterate_leaf_refs(
1410 (struct extent_inode_elem
*)ref_node
->aux
,
1411 root_node
->val
, extent_item_objectid
,
1418 free_leaf_list(refs
);
1421 if (!search_commit_root
) {
1422 btrfs_put_tree_mod_seq(fs_info
, &tree_mod_seq_elem
);
1423 btrfs_end_transaction(trans
, fs_info
->extent_root
);
1429 int iterate_inodes_from_logical(u64 logical
, struct btrfs_fs_info
*fs_info
,
1430 struct btrfs_path
*path
,
1431 iterate_extent_inodes_t
*iterate
, void *ctx
)
1434 u64 extent_item_pos
;
1435 struct btrfs_key found_key
;
1436 int search_commit_root
= path
->search_commit_root
;
1438 ret
= extent_from_logical(fs_info
, logical
, path
,
1440 btrfs_release_path(path
);
1443 if (ret
& BTRFS_EXTENT_FLAG_TREE_BLOCK
)
1446 extent_item_pos
= logical
- found_key
.objectid
;
1447 ret
= iterate_extent_inodes(fs_info
, found_key
.objectid
,
1448 extent_item_pos
, search_commit_root
,
1454 static int iterate_irefs(u64 inum
, struct btrfs_root
*fs_root
,
1455 struct btrfs_path
*path
,
1456 iterate_irefs_t
*iterate
, void *ctx
)
1465 struct extent_buffer
*eb
;
1466 struct btrfs_item
*item
;
1467 struct btrfs_inode_ref
*iref
;
1468 struct btrfs_key found_key
;
1471 path
->leave_spinning
= 1;
1472 ret
= inode_ref_info(inum
, parent
? parent
+1 : 0, fs_root
, path
,
1477 ret
= found
? 0 : -ENOENT
;
1482 parent
= found_key
.offset
;
1483 slot
= path
->slots
[0];
1484 eb
= path
->nodes
[0];
1485 /* make sure we can use eb after releasing the path */
1486 atomic_inc(&eb
->refs
);
1487 btrfs_tree_read_lock(eb
);
1488 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1489 btrfs_release_path(path
);
1491 item
= btrfs_item_nr(eb
, slot
);
1492 iref
= btrfs_item_ptr(eb
, slot
, struct btrfs_inode_ref
);
1494 for (cur
= 0; cur
< btrfs_item_size(eb
, item
); cur
+= len
) {
1495 name_len
= btrfs_inode_ref_name_len(eb
, iref
);
1496 /* path must be released before calling iterate()! */
1497 pr_debug("following ref at offset %u for inode %llu in "
1499 (unsigned long long)found_key
.objectid
,
1500 (unsigned long long)fs_root
->objectid
);
1501 ret
= iterate(parent
, iref
, eb
, ctx
);
1504 len
= sizeof(*iref
) + name_len
;
1505 iref
= (struct btrfs_inode_ref
*)((char *)iref
+ len
);
1507 btrfs_tree_read_unlock_blocking(eb
);
1508 free_extent_buffer(eb
);
1511 btrfs_release_path(path
);
1517 * returns 0 if the path could be dumped (probably truncated)
1518 * returns <0 in case of an error
1520 static int inode_to_path(u64 inum
, struct btrfs_inode_ref
*iref
,
1521 struct extent_buffer
*eb
, void *ctx
)
1523 struct inode_fs_paths
*ipath
= ctx
;
1526 int i
= ipath
->fspath
->elem_cnt
;
1527 const int s_ptr
= sizeof(char *);
1530 bytes_left
= ipath
->fspath
->bytes_left
> s_ptr
?
1531 ipath
->fspath
->bytes_left
- s_ptr
: 0;
1533 fspath_min
= (char *)ipath
->fspath
->val
+ (i
+ 1) * s_ptr
;
1534 fspath
= btrfs_iref_to_path(ipath
->fs_root
, ipath
->btrfs_path
, iref
, eb
,
1535 inum
, fspath_min
, bytes_left
);
1537 return PTR_ERR(fspath
);
1539 if (fspath
> fspath_min
) {
1540 pr_debug("path resolved: %s\n", fspath
);
1541 ipath
->fspath
->val
[i
] = (u64
)(unsigned long)fspath
;
1542 ++ipath
->fspath
->elem_cnt
;
1543 ipath
->fspath
->bytes_left
= fspath
- fspath_min
;
1545 pr_debug("missed path, not enough space. missing bytes: %lu, "
1546 "constructed so far: %s\n",
1547 (unsigned long)(fspath_min
- fspath
), fspath_min
);
1548 ++ipath
->fspath
->elem_missed
;
1549 ipath
->fspath
->bytes_missing
+= fspath_min
- fspath
;
1550 ipath
->fspath
->bytes_left
= 0;
1557 * this dumps all file system paths to the inode into the ipath struct, provided
1558 * is has been created large enough. each path is zero-terminated and accessed
1559 * from ipath->fspath->val[i].
1560 * when it returns, there are ipath->fspath->elem_cnt number of paths available
1561 * in ipath->fspath->val[]. when the allocated space wasn't sufficient, the
1562 * number of missed paths in recored in ipath->fspath->elem_missed, otherwise,
1563 * it's zero. ipath->fspath->bytes_missing holds the number of bytes that would
1564 * have been needed to return all paths.
1566 int paths_from_inode(u64 inum
, struct inode_fs_paths
*ipath
)
1568 return iterate_irefs(inum
, ipath
->fs_root
, ipath
->btrfs_path
,
1569 inode_to_path
, ipath
);
1572 struct btrfs_data_container
*init_data_container(u32 total_bytes
)
1574 struct btrfs_data_container
*data
;
1577 alloc_bytes
= max_t(size_t, total_bytes
, sizeof(*data
));
1578 data
= kmalloc(alloc_bytes
, GFP_NOFS
);
1580 return ERR_PTR(-ENOMEM
);
1582 if (total_bytes
>= sizeof(*data
)) {
1583 data
->bytes_left
= total_bytes
- sizeof(*data
);
1584 data
->bytes_missing
= 0;
1586 data
->bytes_missing
= sizeof(*data
) - total_bytes
;
1587 data
->bytes_left
= 0;
1591 data
->elem_missed
= 0;
1597 * allocates space to return multiple file system paths for an inode.
1598 * total_bytes to allocate are passed, note that space usable for actual path
1599 * information will be total_bytes - sizeof(struct inode_fs_paths).
1600 * the returned pointer must be freed with free_ipath() in the end.
1602 struct inode_fs_paths
*init_ipath(s32 total_bytes
, struct btrfs_root
*fs_root
,
1603 struct btrfs_path
*path
)
1605 struct inode_fs_paths
*ifp
;
1606 struct btrfs_data_container
*fspath
;
1608 fspath
= init_data_container(total_bytes
);
1610 return (void *)fspath
;
1612 ifp
= kmalloc(sizeof(*ifp
), GFP_NOFS
);
1615 return ERR_PTR(-ENOMEM
);
1618 ifp
->btrfs_path
= path
;
1619 ifp
->fspath
= fspath
;
1620 ifp
->fs_root
= fs_root
;
1625 void free_ipath(struct inode_fs_paths
*ipath
)
1629 kfree(ipath
->fspath
);