2 * Copyright (C) 2007,2008 Oracle. 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/sched.h>
20 #include <linux/slab.h>
21 #include <linux/rbtree.h>
24 #include "transaction.h"
25 #include "print-tree.h"
28 static int split_node(struct btrfs_trans_handle
*trans
, struct btrfs_root
29 *root
, struct btrfs_path
*path
, int level
);
30 static int split_leaf(struct btrfs_trans_handle
*trans
, struct btrfs_root
31 *root
, struct btrfs_key
*ins_key
,
32 struct btrfs_path
*path
, int data_size
, int extend
);
33 static int push_node_left(struct btrfs_trans_handle
*trans
,
34 struct btrfs_root
*root
, struct extent_buffer
*dst
,
35 struct extent_buffer
*src
, int empty
);
36 static int balance_node_right(struct btrfs_trans_handle
*trans
,
37 struct btrfs_root
*root
,
38 struct extent_buffer
*dst_buf
,
39 struct extent_buffer
*src_buf
);
40 static void del_ptr(struct btrfs_root
*root
, struct btrfs_path
*path
,
42 static int tree_mod_log_free_eb(struct btrfs_fs_info
*fs_info
,
43 struct extent_buffer
*eb
);
45 struct btrfs_path
*btrfs_alloc_path(void)
47 struct btrfs_path
*path
;
48 path
= kmem_cache_zalloc(btrfs_path_cachep
, GFP_NOFS
);
53 * set all locked nodes in the path to blocking locks. This should
54 * be done before scheduling
56 noinline
void btrfs_set_path_blocking(struct btrfs_path
*p
)
59 for (i
= 0; i
< BTRFS_MAX_LEVEL
; i
++) {
60 if (!p
->nodes
[i
] || !p
->locks
[i
])
62 btrfs_set_lock_blocking_rw(p
->nodes
[i
], p
->locks
[i
]);
63 if (p
->locks
[i
] == BTRFS_READ_LOCK
)
64 p
->locks
[i
] = BTRFS_READ_LOCK_BLOCKING
;
65 else if (p
->locks
[i
] == BTRFS_WRITE_LOCK
)
66 p
->locks
[i
] = BTRFS_WRITE_LOCK_BLOCKING
;
71 * reset all the locked nodes in the patch to spinning locks.
73 * held is used to keep lockdep happy, when lockdep is enabled
74 * we set held to a blocking lock before we go around and
75 * retake all the spinlocks in the path. You can safely use NULL
78 noinline
void btrfs_clear_path_blocking(struct btrfs_path
*p
,
79 struct extent_buffer
*held
, int held_rw
)
84 btrfs_set_lock_blocking_rw(held
, held_rw
);
85 if (held_rw
== BTRFS_WRITE_LOCK
)
86 held_rw
= BTRFS_WRITE_LOCK_BLOCKING
;
87 else if (held_rw
== BTRFS_READ_LOCK
)
88 held_rw
= BTRFS_READ_LOCK_BLOCKING
;
90 btrfs_set_path_blocking(p
);
92 for (i
= BTRFS_MAX_LEVEL
- 1; i
>= 0; i
--) {
93 if (p
->nodes
[i
] && p
->locks
[i
]) {
94 btrfs_clear_lock_blocking_rw(p
->nodes
[i
], p
->locks
[i
]);
95 if (p
->locks
[i
] == BTRFS_WRITE_LOCK_BLOCKING
)
96 p
->locks
[i
] = BTRFS_WRITE_LOCK
;
97 else if (p
->locks
[i
] == BTRFS_READ_LOCK_BLOCKING
)
98 p
->locks
[i
] = BTRFS_READ_LOCK
;
103 btrfs_clear_lock_blocking_rw(held
, held_rw
);
106 /* this also releases the path */
107 void btrfs_free_path(struct btrfs_path
*p
)
111 btrfs_release_path(p
);
112 kmem_cache_free(btrfs_path_cachep
, p
);
116 * path release drops references on the extent buffers in the path
117 * and it drops any locks held by this path
119 * It is safe to call this on paths that no locks or extent buffers held.
121 noinline
void btrfs_release_path(struct btrfs_path
*p
)
125 for (i
= 0; i
< BTRFS_MAX_LEVEL
; i
++) {
130 btrfs_tree_unlock_rw(p
->nodes
[i
], p
->locks
[i
]);
133 free_extent_buffer(p
->nodes
[i
]);
139 * safely gets a reference on the root node of a tree. A lock
140 * is not taken, so a concurrent writer may put a different node
141 * at the root of the tree. See btrfs_lock_root_node for the
144 * The extent buffer returned by this has a reference taken, so
145 * it won't disappear. It may stop being the root of the tree
146 * at any time because there are no locks held.
148 struct extent_buffer
*btrfs_root_node(struct btrfs_root
*root
)
150 struct extent_buffer
*eb
;
154 eb
= rcu_dereference(root
->node
);
157 * RCU really hurts here, we could free up the root node because
158 * it was cow'ed but we may not get the new root node yet so do
159 * the inc_not_zero dance and if it doesn't work then
160 * synchronize_rcu and try again.
162 if (atomic_inc_not_zero(&eb
->refs
)) {
172 /* loop around taking references on and locking the root node of the
173 * tree until you end up with a lock on the root. A locked buffer
174 * is returned, with a reference held.
176 struct extent_buffer
*btrfs_lock_root_node(struct btrfs_root
*root
)
178 struct extent_buffer
*eb
;
181 eb
= btrfs_root_node(root
);
183 if (eb
== root
->node
)
185 btrfs_tree_unlock(eb
);
186 free_extent_buffer(eb
);
191 /* loop around taking references on and locking the root node of the
192 * tree until you end up with a lock on the root. A locked buffer
193 * is returned, with a reference held.
195 static struct extent_buffer
*btrfs_read_lock_root_node(struct btrfs_root
*root
)
197 struct extent_buffer
*eb
;
200 eb
= btrfs_root_node(root
);
201 btrfs_tree_read_lock(eb
);
202 if (eb
== root
->node
)
204 btrfs_tree_read_unlock(eb
);
205 free_extent_buffer(eb
);
210 /* cowonly root (everything not a reference counted cow subvolume), just get
211 * put onto a simple dirty list. transaction.c walks this to make sure they
212 * get properly updated on disk.
214 static void add_root_to_dirty_list(struct btrfs_root
*root
)
216 if (test_bit(BTRFS_ROOT_DIRTY
, &root
->state
) ||
217 !test_bit(BTRFS_ROOT_TRACK_DIRTY
, &root
->state
))
220 spin_lock(&root
->fs_info
->trans_lock
);
221 if (!test_and_set_bit(BTRFS_ROOT_DIRTY
, &root
->state
)) {
222 /* Want the extent tree to be the last on the list */
223 if (root
->objectid
== BTRFS_EXTENT_TREE_OBJECTID
)
224 list_move_tail(&root
->dirty_list
,
225 &root
->fs_info
->dirty_cowonly_roots
);
227 list_move(&root
->dirty_list
,
228 &root
->fs_info
->dirty_cowonly_roots
);
230 spin_unlock(&root
->fs_info
->trans_lock
);
234 * used by snapshot creation to make a copy of a root for a tree with
235 * a given objectid. The buffer with the new root node is returned in
236 * cow_ret, and this func returns zero on success or a negative error code.
238 int btrfs_copy_root(struct btrfs_trans_handle
*trans
,
239 struct btrfs_root
*root
,
240 struct extent_buffer
*buf
,
241 struct extent_buffer
**cow_ret
, u64 new_root_objectid
)
243 struct extent_buffer
*cow
;
246 struct btrfs_disk_key disk_key
;
248 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
249 trans
->transid
!= root
->fs_info
->running_transaction
->transid
);
250 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
251 trans
->transid
!= root
->last_trans
);
253 level
= btrfs_header_level(buf
);
255 btrfs_item_key(buf
, &disk_key
, 0);
257 btrfs_node_key(buf
, &disk_key
, 0);
259 cow
= btrfs_alloc_tree_block(trans
, root
, 0, new_root_objectid
,
260 &disk_key
, level
, buf
->start
, 0);
264 copy_extent_buffer(cow
, buf
, 0, 0, cow
->len
);
265 btrfs_set_header_bytenr(cow
, cow
->start
);
266 btrfs_set_header_generation(cow
, trans
->transid
);
267 btrfs_set_header_backref_rev(cow
, BTRFS_MIXED_BACKREF_REV
);
268 btrfs_clear_header_flag(cow
, BTRFS_HEADER_FLAG_WRITTEN
|
269 BTRFS_HEADER_FLAG_RELOC
);
270 if (new_root_objectid
== BTRFS_TREE_RELOC_OBJECTID
)
271 btrfs_set_header_flag(cow
, BTRFS_HEADER_FLAG_RELOC
);
273 btrfs_set_header_owner(cow
, new_root_objectid
);
275 write_extent_buffer(cow
, root
->fs_info
->fsid
, btrfs_header_fsid(),
278 WARN_ON(btrfs_header_generation(buf
) > trans
->transid
);
279 if (new_root_objectid
== BTRFS_TREE_RELOC_OBJECTID
)
280 ret
= btrfs_inc_ref(trans
, root
, cow
, 1);
282 ret
= btrfs_inc_ref(trans
, root
, cow
, 0);
287 btrfs_mark_buffer_dirty(cow
);
296 MOD_LOG_KEY_REMOVE_WHILE_FREEING
,
297 MOD_LOG_KEY_REMOVE_WHILE_MOVING
,
299 MOD_LOG_ROOT_REPLACE
,
302 struct tree_mod_move
{
307 struct tree_mod_root
{
312 struct tree_mod_elem
{
314 u64 index
; /* shifted logical */
318 /* this is used for MOD_LOG_KEY_* and MOD_LOG_MOVE_KEYS operations */
321 /* this is used for MOD_LOG_KEY* and MOD_LOG_ROOT_REPLACE */
324 /* those are used for op == MOD_LOG_KEY_{REPLACE,REMOVE} */
325 struct btrfs_disk_key key
;
328 /* this is used for op == MOD_LOG_MOVE_KEYS */
329 struct tree_mod_move move
;
331 /* this is used for op == MOD_LOG_ROOT_REPLACE */
332 struct tree_mod_root old_root
;
335 static inline void tree_mod_log_read_lock(struct btrfs_fs_info
*fs_info
)
337 read_lock(&fs_info
->tree_mod_log_lock
);
340 static inline void tree_mod_log_read_unlock(struct btrfs_fs_info
*fs_info
)
342 read_unlock(&fs_info
->tree_mod_log_lock
);
345 static inline void tree_mod_log_write_lock(struct btrfs_fs_info
*fs_info
)
347 write_lock(&fs_info
->tree_mod_log_lock
);
350 static inline void tree_mod_log_write_unlock(struct btrfs_fs_info
*fs_info
)
352 write_unlock(&fs_info
->tree_mod_log_lock
);
356 * Pull a new tree mod seq number for our operation.
358 static inline u64
btrfs_inc_tree_mod_seq(struct btrfs_fs_info
*fs_info
)
360 return atomic64_inc_return(&fs_info
->tree_mod_seq
);
364 * This adds a new blocker to the tree mod log's blocker list if the @elem
365 * passed does not already have a sequence number set. So when a caller expects
366 * to record tree modifications, it should ensure to set elem->seq to zero
367 * before calling btrfs_get_tree_mod_seq.
368 * Returns a fresh, unused tree log modification sequence number, even if no new
371 u64
btrfs_get_tree_mod_seq(struct btrfs_fs_info
*fs_info
,
372 struct seq_list
*elem
)
374 tree_mod_log_write_lock(fs_info
);
375 spin_lock(&fs_info
->tree_mod_seq_lock
);
377 elem
->seq
= btrfs_inc_tree_mod_seq(fs_info
);
378 list_add_tail(&elem
->list
, &fs_info
->tree_mod_seq_list
);
380 spin_unlock(&fs_info
->tree_mod_seq_lock
);
381 tree_mod_log_write_unlock(fs_info
);
386 void btrfs_put_tree_mod_seq(struct btrfs_fs_info
*fs_info
,
387 struct seq_list
*elem
)
389 struct rb_root
*tm_root
;
390 struct rb_node
*node
;
391 struct rb_node
*next
;
392 struct seq_list
*cur_elem
;
393 struct tree_mod_elem
*tm
;
394 u64 min_seq
= (u64
)-1;
395 u64 seq_putting
= elem
->seq
;
400 spin_lock(&fs_info
->tree_mod_seq_lock
);
401 list_del(&elem
->list
);
404 list_for_each_entry(cur_elem
, &fs_info
->tree_mod_seq_list
, list
) {
405 if (cur_elem
->seq
< min_seq
) {
406 if (seq_putting
> cur_elem
->seq
) {
408 * blocker with lower sequence number exists, we
409 * cannot remove anything from the log
411 spin_unlock(&fs_info
->tree_mod_seq_lock
);
414 min_seq
= cur_elem
->seq
;
417 spin_unlock(&fs_info
->tree_mod_seq_lock
);
420 * anything that's lower than the lowest existing (read: blocked)
421 * sequence number can be removed from the tree.
423 tree_mod_log_write_lock(fs_info
);
424 tm_root
= &fs_info
->tree_mod_log
;
425 for (node
= rb_first(tm_root
); node
; node
= next
) {
426 next
= rb_next(node
);
427 tm
= container_of(node
, struct tree_mod_elem
, node
);
428 if (tm
->seq
> min_seq
)
430 rb_erase(node
, tm_root
);
433 tree_mod_log_write_unlock(fs_info
);
437 * key order of the log:
440 * the index is the shifted logical of the *new* root node for root replace
441 * operations, or the shifted logical of the affected block for all other
444 * Note: must be called with write lock (tree_mod_log_write_lock).
447 __tree_mod_log_insert(struct btrfs_fs_info
*fs_info
, struct tree_mod_elem
*tm
)
449 struct rb_root
*tm_root
;
450 struct rb_node
**new;
451 struct rb_node
*parent
= NULL
;
452 struct tree_mod_elem
*cur
;
456 tm
->seq
= btrfs_inc_tree_mod_seq(fs_info
);
458 tm_root
= &fs_info
->tree_mod_log
;
459 new = &tm_root
->rb_node
;
461 cur
= container_of(*new, struct tree_mod_elem
, node
);
463 if (cur
->index
< tm
->index
)
464 new = &((*new)->rb_left
);
465 else if (cur
->index
> tm
->index
)
466 new = &((*new)->rb_right
);
467 else if (cur
->seq
< tm
->seq
)
468 new = &((*new)->rb_left
);
469 else if (cur
->seq
> tm
->seq
)
470 new = &((*new)->rb_right
);
475 rb_link_node(&tm
->node
, parent
, new);
476 rb_insert_color(&tm
->node
, tm_root
);
481 * Determines if logging can be omitted. Returns 1 if it can. Otherwise, it
482 * returns zero with the tree_mod_log_lock acquired. The caller must hold
483 * this until all tree mod log insertions are recorded in the rb tree and then
484 * call tree_mod_log_write_unlock() to release.
486 static inline int tree_mod_dont_log(struct btrfs_fs_info
*fs_info
,
487 struct extent_buffer
*eb
) {
489 if (list_empty(&(fs_info
)->tree_mod_seq_list
))
491 if (eb
&& btrfs_header_level(eb
) == 0)
494 tree_mod_log_write_lock(fs_info
);
495 if (list_empty(&(fs_info
)->tree_mod_seq_list
)) {
496 tree_mod_log_write_unlock(fs_info
);
503 /* Similar to tree_mod_dont_log, but doesn't acquire any locks. */
504 static inline int tree_mod_need_log(const struct btrfs_fs_info
*fs_info
,
505 struct extent_buffer
*eb
)
508 if (list_empty(&(fs_info
)->tree_mod_seq_list
))
510 if (eb
&& btrfs_header_level(eb
) == 0)
516 static struct tree_mod_elem
*
517 alloc_tree_mod_elem(struct extent_buffer
*eb
, int slot
,
518 enum mod_log_op op
, gfp_t flags
)
520 struct tree_mod_elem
*tm
;
522 tm
= kzalloc(sizeof(*tm
), flags
);
526 tm
->index
= eb
->start
>> PAGE_CACHE_SHIFT
;
527 if (op
!= MOD_LOG_KEY_ADD
) {
528 btrfs_node_key(eb
, &tm
->key
, slot
);
529 tm
->blockptr
= btrfs_node_blockptr(eb
, slot
);
533 tm
->generation
= btrfs_node_ptr_generation(eb
, slot
);
534 RB_CLEAR_NODE(&tm
->node
);
540 tree_mod_log_insert_key(struct btrfs_fs_info
*fs_info
,
541 struct extent_buffer
*eb
, int slot
,
542 enum mod_log_op op
, gfp_t flags
)
544 struct tree_mod_elem
*tm
;
547 if (!tree_mod_need_log(fs_info
, eb
))
550 tm
= alloc_tree_mod_elem(eb
, slot
, op
, flags
);
554 if (tree_mod_dont_log(fs_info
, eb
)) {
559 ret
= __tree_mod_log_insert(fs_info
, tm
);
560 tree_mod_log_write_unlock(fs_info
);
568 tree_mod_log_insert_move(struct btrfs_fs_info
*fs_info
,
569 struct extent_buffer
*eb
, int dst_slot
, int src_slot
,
570 int nr_items
, gfp_t flags
)
572 struct tree_mod_elem
*tm
= NULL
;
573 struct tree_mod_elem
**tm_list
= NULL
;
578 if (!tree_mod_need_log(fs_info
, eb
))
581 tm_list
= kzalloc(nr_items
* sizeof(struct tree_mod_elem
*), flags
);
585 tm
= kzalloc(sizeof(*tm
), flags
);
591 tm
->index
= eb
->start
>> PAGE_CACHE_SHIFT
;
593 tm
->move
.dst_slot
= dst_slot
;
594 tm
->move
.nr_items
= nr_items
;
595 tm
->op
= MOD_LOG_MOVE_KEYS
;
597 for (i
= 0; i
+ dst_slot
< src_slot
&& i
< nr_items
; i
++) {
598 tm_list
[i
] = alloc_tree_mod_elem(eb
, i
+ dst_slot
,
599 MOD_LOG_KEY_REMOVE_WHILE_MOVING
, flags
);
606 if (tree_mod_dont_log(fs_info
, eb
))
611 * When we override something during the move, we log these removals.
612 * This can only happen when we move towards the beginning of the
613 * buffer, i.e. dst_slot < src_slot.
615 for (i
= 0; i
+ dst_slot
< src_slot
&& i
< nr_items
; i
++) {
616 ret
= __tree_mod_log_insert(fs_info
, tm_list
[i
]);
621 ret
= __tree_mod_log_insert(fs_info
, tm
);
624 tree_mod_log_write_unlock(fs_info
);
629 for (i
= 0; i
< nr_items
; i
++) {
630 if (tm_list
[i
] && !RB_EMPTY_NODE(&tm_list
[i
]->node
))
631 rb_erase(&tm_list
[i
]->node
, &fs_info
->tree_mod_log
);
635 tree_mod_log_write_unlock(fs_info
);
643 __tree_mod_log_free_eb(struct btrfs_fs_info
*fs_info
,
644 struct tree_mod_elem
**tm_list
,
650 for (i
= nritems
- 1; i
>= 0; i
--) {
651 ret
= __tree_mod_log_insert(fs_info
, tm_list
[i
]);
653 for (j
= nritems
- 1; j
> i
; j
--)
654 rb_erase(&tm_list
[j
]->node
,
655 &fs_info
->tree_mod_log
);
664 tree_mod_log_insert_root(struct btrfs_fs_info
*fs_info
,
665 struct extent_buffer
*old_root
,
666 struct extent_buffer
*new_root
, gfp_t flags
,
669 struct tree_mod_elem
*tm
= NULL
;
670 struct tree_mod_elem
**tm_list
= NULL
;
675 if (!tree_mod_need_log(fs_info
, NULL
))
678 if (log_removal
&& btrfs_header_level(old_root
) > 0) {
679 nritems
= btrfs_header_nritems(old_root
);
680 tm_list
= kzalloc(nritems
* sizeof(struct tree_mod_elem
*),
686 for (i
= 0; i
< nritems
; i
++) {
687 tm_list
[i
] = alloc_tree_mod_elem(old_root
, i
,
688 MOD_LOG_KEY_REMOVE_WHILE_FREEING
, flags
);
696 tm
= kzalloc(sizeof(*tm
), flags
);
702 tm
->index
= new_root
->start
>> PAGE_CACHE_SHIFT
;
703 tm
->old_root
.logical
= old_root
->start
;
704 tm
->old_root
.level
= btrfs_header_level(old_root
);
705 tm
->generation
= btrfs_header_generation(old_root
);
706 tm
->op
= MOD_LOG_ROOT_REPLACE
;
708 if (tree_mod_dont_log(fs_info
, NULL
))
712 ret
= __tree_mod_log_free_eb(fs_info
, tm_list
, nritems
);
714 ret
= __tree_mod_log_insert(fs_info
, tm
);
716 tree_mod_log_write_unlock(fs_info
);
725 for (i
= 0; i
< nritems
; i
++)
734 static struct tree_mod_elem
*
735 __tree_mod_log_search(struct btrfs_fs_info
*fs_info
, u64 start
, u64 min_seq
,
738 struct rb_root
*tm_root
;
739 struct rb_node
*node
;
740 struct tree_mod_elem
*cur
= NULL
;
741 struct tree_mod_elem
*found
= NULL
;
742 u64 index
= start
>> PAGE_CACHE_SHIFT
;
744 tree_mod_log_read_lock(fs_info
);
745 tm_root
= &fs_info
->tree_mod_log
;
746 node
= tm_root
->rb_node
;
748 cur
= container_of(node
, struct tree_mod_elem
, node
);
749 if (cur
->index
< index
) {
750 node
= node
->rb_left
;
751 } else if (cur
->index
> index
) {
752 node
= node
->rb_right
;
753 } else if (cur
->seq
< min_seq
) {
754 node
= node
->rb_left
;
755 } else if (!smallest
) {
756 /* we want the node with the highest seq */
758 BUG_ON(found
->seq
> cur
->seq
);
760 node
= node
->rb_left
;
761 } else if (cur
->seq
> min_seq
) {
762 /* we want the node with the smallest seq */
764 BUG_ON(found
->seq
< cur
->seq
);
766 node
= node
->rb_right
;
772 tree_mod_log_read_unlock(fs_info
);
778 * this returns the element from the log with the smallest time sequence
779 * value that's in the log (the oldest log item). any element with a time
780 * sequence lower than min_seq will be ignored.
782 static struct tree_mod_elem
*
783 tree_mod_log_search_oldest(struct btrfs_fs_info
*fs_info
, u64 start
,
786 return __tree_mod_log_search(fs_info
, start
, min_seq
, 1);
790 * this returns the element from the log with the largest time sequence
791 * value that's in the log (the most recent log item). any element with
792 * a time sequence lower than min_seq will be ignored.
794 static struct tree_mod_elem
*
795 tree_mod_log_search(struct btrfs_fs_info
*fs_info
, u64 start
, u64 min_seq
)
797 return __tree_mod_log_search(fs_info
, start
, min_seq
, 0);
801 tree_mod_log_eb_copy(struct btrfs_fs_info
*fs_info
, struct extent_buffer
*dst
,
802 struct extent_buffer
*src
, unsigned long dst_offset
,
803 unsigned long src_offset
, int nr_items
)
806 struct tree_mod_elem
**tm_list
= NULL
;
807 struct tree_mod_elem
**tm_list_add
, **tm_list_rem
;
811 if (!tree_mod_need_log(fs_info
, NULL
))
814 if (btrfs_header_level(dst
) == 0 && btrfs_header_level(src
) == 0)
817 tm_list
= kzalloc(nr_items
* 2 * sizeof(struct tree_mod_elem
*),
822 tm_list_add
= tm_list
;
823 tm_list_rem
= tm_list
+ nr_items
;
824 for (i
= 0; i
< nr_items
; i
++) {
825 tm_list_rem
[i
] = alloc_tree_mod_elem(src
, i
+ src_offset
,
826 MOD_LOG_KEY_REMOVE
, GFP_NOFS
);
827 if (!tm_list_rem
[i
]) {
832 tm_list_add
[i
] = alloc_tree_mod_elem(dst
, i
+ dst_offset
,
833 MOD_LOG_KEY_ADD
, GFP_NOFS
);
834 if (!tm_list_add
[i
]) {
840 if (tree_mod_dont_log(fs_info
, NULL
))
844 for (i
= 0; i
< nr_items
; i
++) {
845 ret
= __tree_mod_log_insert(fs_info
, tm_list_rem
[i
]);
848 ret
= __tree_mod_log_insert(fs_info
, tm_list_add
[i
]);
853 tree_mod_log_write_unlock(fs_info
);
859 for (i
= 0; i
< nr_items
* 2; i
++) {
860 if (tm_list
[i
] && !RB_EMPTY_NODE(&tm_list
[i
]->node
))
861 rb_erase(&tm_list
[i
]->node
, &fs_info
->tree_mod_log
);
865 tree_mod_log_write_unlock(fs_info
);
872 tree_mod_log_eb_move(struct btrfs_fs_info
*fs_info
, struct extent_buffer
*dst
,
873 int dst_offset
, int src_offset
, int nr_items
)
876 ret
= tree_mod_log_insert_move(fs_info
, dst
, dst_offset
, src_offset
,
882 tree_mod_log_set_node_key(struct btrfs_fs_info
*fs_info
,
883 struct extent_buffer
*eb
, int slot
, int atomic
)
887 ret
= tree_mod_log_insert_key(fs_info
, eb
, slot
,
889 atomic
? GFP_ATOMIC
: GFP_NOFS
);
894 tree_mod_log_free_eb(struct btrfs_fs_info
*fs_info
, struct extent_buffer
*eb
)
896 struct tree_mod_elem
**tm_list
= NULL
;
901 if (btrfs_header_level(eb
) == 0)
904 if (!tree_mod_need_log(fs_info
, NULL
))
907 nritems
= btrfs_header_nritems(eb
);
908 tm_list
= kzalloc(nritems
* sizeof(struct tree_mod_elem
*),
913 for (i
= 0; i
< nritems
; i
++) {
914 tm_list
[i
] = alloc_tree_mod_elem(eb
, i
,
915 MOD_LOG_KEY_REMOVE_WHILE_FREEING
, GFP_NOFS
);
922 if (tree_mod_dont_log(fs_info
, eb
))
925 ret
= __tree_mod_log_free_eb(fs_info
, tm_list
, nritems
);
926 tree_mod_log_write_unlock(fs_info
);
934 for (i
= 0; i
< nritems
; i
++)
942 tree_mod_log_set_root_pointer(struct btrfs_root
*root
,
943 struct extent_buffer
*new_root_node
,
947 ret
= tree_mod_log_insert_root(root
->fs_info
, root
->node
,
948 new_root_node
, GFP_NOFS
, log_removal
);
953 * check if the tree block can be shared by multiple trees
955 int btrfs_block_can_be_shared(struct btrfs_root
*root
,
956 struct extent_buffer
*buf
)
959 * Tree blocks not in refernece counted trees and tree roots
960 * are never shared. If a block was allocated after the last
961 * snapshot and the block was not allocated by tree relocation,
962 * we know the block is not shared.
964 if (test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
965 buf
!= root
->node
&& buf
!= root
->commit_root
&&
966 (btrfs_header_generation(buf
) <=
967 btrfs_root_last_snapshot(&root
->root_item
) ||
968 btrfs_header_flag(buf
, BTRFS_HEADER_FLAG_RELOC
)))
970 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
971 if (test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
972 btrfs_header_backref_rev(buf
) < BTRFS_MIXED_BACKREF_REV
)
978 static noinline
int update_ref_for_cow(struct btrfs_trans_handle
*trans
,
979 struct btrfs_root
*root
,
980 struct extent_buffer
*buf
,
981 struct extent_buffer
*cow
,
991 * Backrefs update rules:
993 * Always use full backrefs for extent pointers in tree block
994 * allocated by tree relocation.
996 * If a shared tree block is no longer referenced by its owner
997 * tree (btrfs_header_owner(buf) == root->root_key.objectid),
998 * use full backrefs for extent pointers in tree block.
1000 * If a tree block is been relocating
1001 * (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID),
1002 * use full backrefs for extent pointers in tree block.
1003 * The reason for this is some operations (such as drop tree)
1004 * are only allowed for blocks use full backrefs.
1007 if (btrfs_block_can_be_shared(root
, buf
)) {
1008 ret
= btrfs_lookup_extent_info(trans
, root
, buf
->start
,
1009 btrfs_header_level(buf
), 1,
1015 btrfs_std_error(root
->fs_info
, ret
);
1020 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
||
1021 btrfs_header_backref_rev(buf
) < BTRFS_MIXED_BACKREF_REV
)
1022 flags
= BTRFS_BLOCK_FLAG_FULL_BACKREF
;
1027 owner
= btrfs_header_owner(buf
);
1028 BUG_ON(owner
== BTRFS_TREE_RELOC_OBJECTID
&&
1029 !(flags
& BTRFS_BLOCK_FLAG_FULL_BACKREF
));
1032 if ((owner
== root
->root_key
.objectid
||
1033 root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
) &&
1034 !(flags
& BTRFS_BLOCK_FLAG_FULL_BACKREF
)) {
1035 ret
= btrfs_inc_ref(trans
, root
, buf
, 1);
1036 BUG_ON(ret
); /* -ENOMEM */
1038 if (root
->root_key
.objectid
==
1039 BTRFS_TREE_RELOC_OBJECTID
) {
1040 ret
= btrfs_dec_ref(trans
, root
, buf
, 0);
1041 BUG_ON(ret
); /* -ENOMEM */
1042 ret
= btrfs_inc_ref(trans
, root
, cow
, 1);
1043 BUG_ON(ret
); /* -ENOMEM */
1045 new_flags
|= BTRFS_BLOCK_FLAG_FULL_BACKREF
;
1048 if (root
->root_key
.objectid
==
1049 BTRFS_TREE_RELOC_OBJECTID
)
1050 ret
= btrfs_inc_ref(trans
, root
, cow
, 1);
1052 ret
= btrfs_inc_ref(trans
, root
, cow
, 0);
1053 BUG_ON(ret
); /* -ENOMEM */
1055 if (new_flags
!= 0) {
1056 int level
= btrfs_header_level(buf
);
1058 ret
= btrfs_set_disk_extent_flags(trans
, root
,
1061 new_flags
, level
, 0);
1066 if (flags
& BTRFS_BLOCK_FLAG_FULL_BACKREF
) {
1067 if (root
->root_key
.objectid
==
1068 BTRFS_TREE_RELOC_OBJECTID
)
1069 ret
= btrfs_inc_ref(trans
, root
, cow
, 1);
1071 ret
= btrfs_inc_ref(trans
, root
, cow
, 0);
1072 BUG_ON(ret
); /* -ENOMEM */
1073 ret
= btrfs_dec_ref(trans
, root
, buf
, 1);
1074 BUG_ON(ret
); /* -ENOMEM */
1076 clean_tree_block(trans
, root
, buf
);
1083 * does the dirty work in cow of a single block. The parent block (if
1084 * supplied) is updated to point to the new cow copy. The new buffer is marked
1085 * dirty and returned locked. If you modify the block it needs to be marked
1088 * search_start -- an allocation hint for the new block
1090 * empty_size -- a hint that you plan on doing more cow. This is the size in
1091 * bytes the allocator should try to find free next to the block it returns.
1092 * This is just a hint and may be ignored by the allocator.
1094 static noinline
int __btrfs_cow_block(struct btrfs_trans_handle
*trans
,
1095 struct btrfs_root
*root
,
1096 struct extent_buffer
*buf
,
1097 struct extent_buffer
*parent
, int parent_slot
,
1098 struct extent_buffer
**cow_ret
,
1099 u64 search_start
, u64 empty_size
)
1101 struct btrfs_disk_key disk_key
;
1102 struct extent_buffer
*cow
;
1105 int unlock_orig
= 0;
1108 if (*cow_ret
== buf
)
1111 btrfs_assert_tree_locked(buf
);
1113 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
1114 trans
->transid
!= root
->fs_info
->running_transaction
->transid
);
1115 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
1116 trans
->transid
!= root
->last_trans
);
1118 level
= btrfs_header_level(buf
);
1121 btrfs_item_key(buf
, &disk_key
, 0);
1123 btrfs_node_key(buf
, &disk_key
, 0);
1125 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
) {
1127 parent_start
= parent
->start
;
1133 cow
= btrfs_alloc_tree_block(trans
, root
, parent_start
,
1134 root
->root_key
.objectid
, &disk_key
, level
,
1135 search_start
, empty_size
);
1137 return PTR_ERR(cow
);
1139 /* cow is set to blocking by btrfs_init_new_buffer */
1141 copy_extent_buffer(cow
, buf
, 0, 0, cow
->len
);
1142 btrfs_set_header_bytenr(cow
, cow
->start
);
1143 btrfs_set_header_generation(cow
, trans
->transid
);
1144 btrfs_set_header_backref_rev(cow
, BTRFS_MIXED_BACKREF_REV
);
1145 btrfs_clear_header_flag(cow
, BTRFS_HEADER_FLAG_WRITTEN
|
1146 BTRFS_HEADER_FLAG_RELOC
);
1147 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
)
1148 btrfs_set_header_flag(cow
, BTRFS_HEADER_FLAG_RELOC
);
1150 btrfs_set_header_owner(cow
, root
->root_key
.objectid
);
1152 write_extent_buffer(cow
, root
->fs_info
->fsid
, btrfs_header_fsid(),
1155 ret
= update_ref_for_cow(trans
, root
, buf
, cow
, &last_ref
);
1157 btrfs_abort_transaction(trans
, root
, ret
);
1161 if (test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
)) {
1162 ret
= btrfs_reloc_cow_block(trans
, root
, buf
, cow
);
1167 if (buf
== root
->node
) {
1168 WARN_ON(parent
&& parent
!= buf
);
1169 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
||
1170 btrfs_header_backref_rev(buf
) < BTRFS_MIXED_BACKREF_REV
)
1171 parent_start
= buf
->start
;
1175 extent_buffer_get(cow
);
1176 tree_mod_log_set_root_pointer(root
, cow
, 1);
1177 rcu_assign_pointer(root
->node
, cow
);
1179 btrfs_free_tree_block(trans
, root
, buf
, parent_start
,
1181 free_extent_buffer(buf
);
1182 add_root_to_dirty_list(root
);
1184 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
)
1185 parent_start
= parent
->start
;
1189 WARN_ON(trans
->transid
!= btrfs_header_generation(parent
));
1190 tree_mod_log_insert_key(root
->fs_info
, parent
, parent_slot
,
1191 MOD_LOG_KEY_REPLACE
, GFP_NOFS
);
1192 btrfs_set_node_blockptr(parent
, parent_slot
,
1194 btrfs_set_node_ptr_generation(parent
, parent_slot
,
1196 btrfs_mark_buffer_dirty(parent
);
1198 ret
= tree_mod_log_free_eb(root
->fs_info
, buf
);
1200 btrfs_abort_transaction(trans
, root
, ret
);
1204 btrfs_free_tree_block(trans
, root
, buf
, parent_start
,
1208 btrfs_tree_unlock(buf
);
1209 free_extent_buffer_stale(buf
);
1210 btrfs_mark_buffer_dirty(cow
);
1216 * returns the logical address of the oldest predecessor of the given root.
1217 * entries older than time_seq are ignored.
1219 static struct tree_mod_elem
*
1220 __tree_mod_log_oldest_root(struct btrfs_fs_info
*fs_info
,
1221 struct extent_buffer
*eb_root
, u64 time_seq
)
1223 struct tree_mod_elem
*tm
;
1224 struct tree_mod_elem
*found
= NULL
;
1225 u64 root_logical
= eb_root
->start
;
1232 * the very last operation that's logged for a root is the replacement
1233 * operation (if it is replaced at all). this has the index of the *new*
1234 * root, making it the very first operation that's logged for this root.
1237 tm
= tree_mod_log_search_oldest(fs_info
, root_logical
,
1242 * if there are no tree operation for the oldest root, we simply
1243 * return it. this should only happen if that (old) root is at
1250 * if there's an operation that's not a root replacement, we
1251 * found the oldest version of our root. normally, we'll find a
1252 * MOD_LOG_KEY_REMOVE_WHILE_FREEING operation here.
1254 if (tm
->op
!= MOD_LOG_ROOT_REPLACE
)
1258 root_logical
= tm
->old_root
.logical
;
1262 /* if there's no old root to return, return what we found instead */
1270 * tm is a pointer to the first operation to rewind within eb. then, all
1271 * previous operations will be rewinded (until we reach something older than
1275 __tree_mod_log_rewind(struct btrfs_fs_info
*fs_info
, struct extent_buffer
*eb
,
1276 u64 time_seq
, struct tree_mod_elem
*first_tm
)
1279 struct rb_node
*next
;
1280 struct tree_mod_elem
*tm
= first_tm
;
1281 unsigned long o_dst
;
1282 unsigned long o_src
;
1283 unsigned long p_size
= sizeof(struct btrfs_key_ptr
);
1285 n
= btrfs_header_nritems(eb
);
1286 tree_mod_log_read_lock(fs_info
);
1287 while (tm
&& tm
->seq
>= time_seq
) {
1289 * all the operations are recorded with the operator used for
1290 * the modification. as we're going backwards, we do the
1291 * opposite of each operation here.
1294 case MOD_LOG_KEY_REMOVE_WHILE_FREEING
:
1295 BUG_ON(tm
->slot
< n
);
1297 case MOD_LOG_KEY_REMOVE_WHILE_MOVING
:
1298 case MOD_LOG_KEY_REMOVE
:
1299 btrfs_set_node_key(eb
, &tm
->key
, tm
->slot
);
1300 btrfs_set_node_blockptr(eb
, tm
->slot
, tm
->blockptr
);
1301 btrfs_set_node_ptr_generation(eb
, tm
->slot
,
1305 case MOD_LOG_KEY_REPLACE
:
1306 BUG_ON(tm
->slot
>= n
);
1307 btrfs_set_node_key(eb
, &tm
->key
, tm
->slot
);
1308 btrfs_set_node_blockptr(eb
, tm
->slot
, tm
->blockptr
);
1309 btrfs_set_node_ptr_generation(eb
, tm
->slot
,
1312 case MOD_LOG_KEY_ADD
:
1313 /* if a move operation is needed it's in the log */
1316 case MOD_LOG_MOVE_KEYS
:
1317 o_dst
= btrfs_node_key_ptr_offset(tm
->slot
);
1318 o_src
= btrfs_node_key_ptr_offset(tm
->move
.dst_slot
);
1319 memmove_extent_buffer(eb
, o_dst
, o_src
,
1320 tm
->move
.nr_items
* p_size
);
1322 case MOD_LOG_ROOT_REPLACE
:
1324 * this operation is special. for roots, this must be
1325 * handled explicitly before rewinding.
1326 * for non-roots, this operation may exist if the node
1327 * was a root: root A -> child B; then A gets empty and
1328 * B is promoted to the new root. in the mod log, we'll
1329 * have a root-replace operation for B, a tree block
1330 * that is no root. we simply ignore that operation.
1334 next
= rb_next(&tm
->node
);
1337 tm
= container_of(next
, struct tree_mod_elem
, node
);
1338 if (tm
->index
!= first_tm
->index
)
1341 tree_mod_log_read_unlock(fs_info
);
1342 btrfs_set_header_nritems(eb
, n
);
1346 * Called with eb read locked. If the buffer cannot be rewinded, the same buffer
1347 * is returned. If rewind operations happen, a fresh buffer is returned. The
1348 * returned buffer is always read-locked. If the returned buffer is not the
1349 * input buffer, the lock on the input buffer is released and the input buffer
1350 * is freed (its refcount is decremented).
1352 static struct extent_buffer
*
1353 tree_mod_log_rewind(struct btrfs_fs_info
*fs_info
, struct btrfs_path
*path
,
1354 struct extent_buffer
*eb
, u64 time_seq
)
1356 struct extent_buffer
*eb_rewin
;
1357 struct tree_mod_elem
*tm
;
1362 if (btrfs_header_level(eb
) == 0)
1365 tm
= tree_mod_log_search(fs_info
, eb
->start
, time_seq
);
1369 btrfs_set_path_blocking(path
);
1370 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1372 if (tm
->op
== MOD_LOG_KEY_REMOVE_WHILE_FREEING
) {
1373 BUG_ON(tm
->slot
!= 0);
1374 eb_rewin
= alloc_dummy_extent_buffer(fs_info
, eb
->start
);
1376 btrfs_tree_read_unlock_blocking(eb
);
1377 free_extent_buffer(eb
);
1380 btrfs_set_header_bytenr(eb_rewin
, eb
->start
);
1381 btrfs_set_header_backref_rev(eb_rewin
,
1382 btrfs_header_backref_rev(eb
));
1383 btrfs_set_header_owner(eb_rewin
, btrfs_header_owner(eb
));
1384 btrfs_set_header_level(eb_rewin
, btrfs_header_level(eb
));
1386 eb_rewin
= btrfs_clone_extent_buffer(eb
);
1388 btrfs_tree_read_unlock_blocking(eb
);
1389 free_extent_buffer(eb
);
1394 btrfs_clear_path_blocking(path
, NULL
, BTRFS_READ_LOCK
);
1395 btrfs_tree_read_unlock_blocking(eb
);
1396 free_extent_buffer(eb
);
1398 extent_buffer_get(eb_rewin
);
1399 btrfs_tree_read_lock(eb_rewin
);
1400 __tree_mod_log_rewind(fs_info
, eb_rewin
, time_seq
, tm
);
1401 WARN_ON(btrfs_header_nritems(eb_rewin
) >
1402 BTRFS_NODEPTRS_PER_BLOCK(fs_info
->tree_root
));
1408 * get_old_root() rewinds the state of @root's root node to the given @time_seq
1409 * value. If there are no changes, the current root->root_node is returned. If
1410 * anything changed in between, there's a fresh buffer allocated on which the
1411 * rewind operations are done. In any case, the returned buffer is read locked.
1412 * Returns NULL on error (with no locks held).
1414 static inline struct extent_buffer
*
1415 get_old_root(struct btrfs_root
*root
, u64 time_seq
)
1417 struct tree_mod_elem
*tm
;
1418 struct extent_buffer
*eb
= NULL
;
1419 struct extent_buffer
*eb_root
;
1420 struct extent_buffer
*old
;
1421 struct tree_mod_root
*old_root
= NULL
;
1422 u64 old_generation
= 0;
1425 eb_root
= btrfs_read_lock_root_node(root
);
1426 tm
= __tree_mod_log_oldest_root(root
->fs_info
, eb_root
, time_seq
);
1430 if (tm
->op
== MOD_LOG_ROOT_REPLACE
) {
1431 old_root
= &tm
->old_root
;
1432 old_generation
= tm
->generation
;
1433 logical
= old_root
->logical
;
1435 logical
= eb_root
->start
;
1438 tm
= tree_mod_log_search(root
->fs_info
, logical
, time_seq
);
1439 if (old_root
&& tm
&& tm
->op
!= MOD_LOG_KEY_REMOVE_WHILE_FREEING
) {
1440 btrfs_tree_read_unlock(eb_root
);
1441 free_extent_buffer(eb_root
);
1442 old
= read_tree_block(root
, logical
, 0);
1443 if (WARN_ON(!old
|| !extent_buffer_uptodate(old
))) {
1444 free_extent_buffer(old
);
1445 btrfs_warn(root
->fs_info
,
1446 "failed to read tree block %llu from get_old_root", logical
);
1448 eb
= btrfs_clone_extent_buffer(old
);
1449 free_extent_buffer(old
);
1451 } else if (old_root
) {
1452 btrfs_tree_read_unlock(eb_root
);
1453 free_extent_buffer(eb_root
);
1454 eb
= alloc_dummy_extent_buffer(root
->fs_info
, logical
);
1456 btrfs_set_lock_blocking_rw(eb_root
, BTRFS_READ_LOCK
);
1457 eb
= btrfs_clone_extent_buffer(eb_root
);
1458 btrfs_tree_read_unlock_blocking(eb_root
);
1459 free_extent_buffer(eb_root
);
1464 extent_buffer_get(eb
);
1465 btrfs_tree_read_lock(eb
);
1467 btrfs_set_header_bytenr(eb
, eb
->start
);
1468 btrfs_set_header_backref_rev(eb
, BTRFS_MIXED_BACKREF_REV
);
1469 btrfs_set_header_owner(eb
, btrfs_header_owner(eb_root
));
1470 btrfs_set_header_level(eb
, old_root
->level
);
1471 btrfs_set_header_generation(eb
, old_generation
);
1474 __tree_mod_log_rewind(root
->fs_info
, eb
, time_seq
, tm
);
1476 WARN_ON(btrfs_header_level(eb
) != 0);
1477 WARN_ON(btrfs_header_nritems(eb
) > BTRFS_NODEPTRS_PER_BLOCK(root
));
1482 int btrfs_old_root_level(struct btrfs_root
*root
, u64 time_seq
)
1484 struct tree_mod_elem
*tm
;
1486 struct extent_buffer
*eb_root
= btrfs_root_node(root
);
1488 tm
= __tree_mod_log_oldest_root(root
->fs_info
, eb_root
, time_seq
);
1489 if (tm
&& tm
->op
== MOD_LOG_ROOT_REPLACE
) {
1490 level
= tm
->old_root
.level
;
1492 level
= btrfs_header_level(eb_root
);
1494 free_extent_buffer(eb_root
);
1499 static inline int should_cow_block(struct btrfs_trans_handle
*trans
,
1500 struct btrfs_root
*root
,
1501 struct extent_buffer
*buf
)
1503 if (btrfs_test_is_dummy_root(root
))
1506 /* ensure we can see the force_cow */
1510 * We do not need to cow a block if
1511 * 1) this block is not created or changed in this transaction;
1512 * 2) this block does not belong to TREE_RELOC tree;
1513 * 3) the root is not forced COW.
1515 * What is forced COW:
1516 * when we create snapshot during commiting the transaction,
1517 * after we've finished coping src root, we must COW the shared
1518 * block to ensure the metadata consistency.
1520 if (btrfs_header_generation(buf
) == trans
->transid
&&
1521 !btrfs_header_flag(buf
, BTRFS_HEADER_FLAG_WRITTEN
) &&
1522 !(root
->root_key
.objectid
!= BTRFS_TREE_RELOC_OBJECTID
&&
1523 btrfs_header_flag(buf
, BTRFS_HEADER_FLAG_RELOC
)) &&
1524 !test_bit(BTRFS_ROOT_FORCE_COW
, &root
->state
))
1530 * cows a single block, see __btrfs_cow_block for the real work.
1531 * This version of it has extra checks so that a block isn't cow'd more than
1532 * once per transaction, as long as it hasn't been written yet
1534 noinline
int btrfs_cow_block(struct btrfs_trans_handle
*trans
,
1535 struct btrfs_root
*root
, struct extent_buffer
*buf
,
1536 struct extent_buffer
*parent
, int parent_slot
,
1537 struct extent_buffer
**cow_ret
)
1542 if (trans
->transaction
!= root
->fs_info
->running_transaction
)
1543 WARN(1, KERN_CRIT
"trans %llu running %llu\n",
1545 root
->fs_info
->running_transaction
->transid
);
1547 if (trans
->transid
!= root
->fs_info
->generation
)
1548 WARN(1, KERN_CRIT
"trans %llu running %llu\n",
1549 trans
->transid
, root
->fs_info
->generation
);
1551 if (!should_cow_block(trans
, root
, buf
)) {
1556 search_start
= buf
->start
& ~((u64
)(1024 * 1024 * 1024) - 1);
1559 btrfs_set_lock_blocking(parent
);
1560 btrfs_set_lock_blocking(buf
);
1562 ret
= __btrfs_cow_block(trans
, root
, buf
, parent
,
1563 parent_slot
, cow_ret
, search_start
, 0);
1565 trace_btrfs_cow_block(root
, buf
, *cow_ret
);
1571 * helper function for defrag to decide if two blocks pointed to by a
1572 * node are actually close by
1574 static int close_blocks(u64 blocknr
, u64 other
, u32 blocksize
)
1576 if (blocknr
< other
&& other
- (blocknr
+ blocksize
) < 32768)
1578 if (blocknr
> other
&& blocknr
- (other
+ blocksize
) < 32768)
1584 * compare two keys in a memcmp fashion
1586 static int comp_keys(struct btrfs_disk_key
*disk
, struct btrfs_key
*k2
)
1588 struct btrfs_key k1
;
1590 btrfs_disk_key_to_cpu(&k1
, disk
);
1592 return btrfs_comp_cpu_keys(&k1
, k2
);
1596 * same as comp_keys only with two btrfs_key's
1598 int btrfs_comp_cpu_keys(struct btrfs_key
*k1
, struct btrfs_key
*k2
)
1600 if (k1
->objectid
> k2
->objectid
)
1602 if (k1
->objectid
< k2
->objectid
)
1604 if (k1
->type
> k2
->type
)
1606 if (k1
->type
< k2
->type
)
1608 if (k1
->offset
> k2
->offset
)
1610 if (k1
->offset
< k2
->offset
)
1616 * this is used by the defrag code to go through all the
1617 * leaves pointed to by a node and reallocate them so that
1618 * disk order is close to key order
1620 int btrfs_realloc_node(struct btrfs_trans_handle
*trans
,
1621 struct btrfs_root
*root
, struct extent_buffer
*parent
,
1622 int start_slot
, u64
*last_ret
,
1623 struct btrfs_key
*progress
)
1625 struct extent_buffer
*cur
;
1628 u64 search_start
= *last_ret
;
1638 int progress_passed
= 0;
1639 struct btrfs_disk_key disk_key
;
1641 parent_level
= btrfs_header_level(parent
);
1643 WARN_ON(trans
->transaction
!= root
->fs_info
->running_transaction
);
1644 WARN_ON(trans
->transid
!= root
->fs_info
->generation
);
1646 parent_nritems
= btrfs_header_nritems(parent
);
1647 blocksize
= root
->nodesize
;
1648 end_slot
= parent_nritems
- 1;
1650 if (parent_nritems
<= 1)
1653 btrfs_set_lock_blocking(parent
);
1655 for (i
= start_slot
; i
<= end_slot
; i
++) {
1658 btrfs_node_key(parent
, &disk_key
, i
);
1659 if (!progress_passed
&& comp_keys(&disk_key
, progress
) < 0)
1662 progress_passed
= 1;
1663 blocknr
= btrfs_node_blockptr(parent
, i
);
1664 gen
= btrfs_node_ptr_generation(parent
, i
);
1665 if (last_block
== 0)
1666 last_block
= blocknr
;
1669 other
= btrfs_node_blockptr(parent
, i
- 1);
1670 close
= close_blocks(blocknr
, other
, blocksize
);
1672 if (!close
&& i
< end_slot
) {
1673 other
= btrfs_node_blockptr(parent
, i
+ 1);
1674 close
= close_blocks(blocknr
, other
, blocksize
);
1677 last_block
= blocknr
;
1681 cur
= btrfs_find_tree_block(root
, blocknr
);
1683 uptodate
= btrfs_buffer_uptodate(cur
, gen
, 0);
1686 if (!cur
|| !uptodate
) {
1688 cur
= read_tree_block(root
, blocknr
, gen
);
1689 if (!cur
|| !extent_buffer_uptodate(cur
)) {
1690 free_extent_buffer(cur
);
1693 } else if (!uptodate
) {
1694 err
= btrfs_read_buffer(cur
, gen
);
1696 free_extent_buffer(cur
);
1701 if (search_start
== 0)
1702 search_start
= last_block
;
1704 btrfs_tree_lock(cur
);
1705 btrfs_set_lock_blocking(cur
);
1706 err
= __btrfs_cow_block(trans
, root
, cur
, parent
, i
,
1709 (end_slot
- i
) * blocksize
));
1711 btrfs_tree_unlock(cur
);
1712 free_extent_buffer(cur
);
1715 search_start
= cur
->start
;
1716 last_block
= cur
->start
;
1717 *last_ret
= search_start
;
1718 btrfs_tree_unlock(cur
);
1719 free_extent_buffer(cur
);
1725 * The leaf data grows from end-to-front in the node.
1726 * this returns the address of the start of the last item,
1727 * which is the stop of the leaf data stack
1729 static inline unsigned int leaf_data_end(struct btrfs_root
*root
,
1730 struct extent_buffer
*leaf
)
1732 u32 nr
= btrfs_header_nritems(leaf
);
1734 return BTRFS_LEAF_DATA_SIZE(root
);
1735 return btrfs_item_offset_nr(leaf
, nr
- 1);
1740 * search for key in the extent_buffer. The items start at offset p,
1741 * and they are item_size apart. There are 'max' items in p.
1743 * the slot in the array is returned via slot, and it points to
1744 * the place where you would insert key if it is not found in
1747 * slot may point to max if the key is bigger than all of the keys
1749 static noinline
int generic_bin_search(struct extent_buffer
*eb
,
1751 int item_size
, struct btrfs_key
*key
,
1758 struct btrfs_disk_key
*tmp
= NULL
;
1759 struct btrfs_disk_key unaligned
;
1760 unsigned long offset
;
1762 unsigned long map_start
= 0;
1763 unsigned long map_len
= 0;
1766 while (low
< high
) {
1767 mid
= (low
+ high
) / 2;
1768 offset
= p
+ mid
* item_size
;
1770 if (!kaddr
|| offset
< map_start
||
1771 (offset
+ sizeof(struct btrfs_disk_key
)) >
1772 map_start
+ map_len
) {
1774 err
= map_private_extent_buffer(eb
, offset
,
1775 sizeof(struct btrfs_disk_key
),
1776 &kaddr
, &map_start
, &map_len
);
1779 tmp
= (struct btrfs_disk_key
*)(kaddr
+ offset
-
1782 read_extent_buffer(eb
, &unaligned
,
1783 offset
, sizeof(unaligned
));
1788 tmp
= (struct btrfs_disk_key
*)(kaddr
+ offset
-
1791 ret
= comp_keys(tmp
, key
);
1807 * simple bin_search frontend that does the right thing for
1810 static int bin_search(struct extent_buffer
*eb
, struct btrfs_key
*key
,
1811 int level
, int *slot
)
1814 return generic_bin_search(eb
,
1815 offsetof(struct btrfs_leaf
, items
),
1816 sizeof(struct btrfs_item
),
1817 key
, btrfs_header_nritems(eb
),
1820 return generic_bin_search(eb
,
1821 offsetof(struct btrfs_node
, ptrs
),
1822 sizeof(struct btrfs_key_ptr
),
1823 key
, btrfs_header_nritems(eb
),
1827 int btrfs_bin_search(struct extent_buffer
*eb
, struct btrfs_key
*key
,
1828 int level
, int *slot
)
1830 return bin_search(eb
, key
, level
, slot
);
1833 static void root_add_used(struct btrfs_root
*root
, u32 size
)
1835 spin_lock(&root
->accounting_lock
);
1836 btrfs_set_root_used(&root
->root_item
,
1837 btrfs_root_used(&root
->root_item
) + size
);
1838 spin_unlock(&root
->accounting_lock
);
1841 static void root_sub_used(struct btrfs_root
*root
, u32 size
)
1843 spin_lock(&root
->accounting_lock
);
1844 btrfs_set_root_used(&root
->root_item
,
1845 btrfs_root_used(&root
->root_item
) - size
);
1846 spin_unlock(&root
->accounting_lock
);
1849 /* given a node and slot number, this reads the blocks it points to. The
1850 * extent buffer is returned with a reference taken (but unlocked).
1851 * NULL is returned on error.
1853 static noinline
struct extent_buffer
*read_node_slot(struct btrfs_root
*root
,
1854 struct extent_buffer
*parent
, int slot
)
1856 int level
= btrfs_header_level(parent
);
1857 struct extent_buffer
*eb
;
1861 if (slot
>= btrfs_header_nritems(parent
))
1866 eb
= read_tree_block(root
, btrfs_node_blockptr(parent
, slot
),
1867 btrfs_node_ptr_generation(parent
, slot
));
1868 if (eb
&& !extent_buffer_uptodate(eb
)) {
1869 free_extent_buffer(eb
);
1877 * node level balancing, used to make sure nodes are in proper order for
1878 * item deletion. We balance from the top down, so we have to make sure
1879 * that a deletion won't leave an node completely empty later on.
1881 static noinline
int balance_level(struct btrfs_trans_handle
*trans
,
1882 struct btrfs_root
*root
,
1883 struct btrfs_path
*path
, int level
)
1885 struct extent_buffer
*right
= NULL
;
1886 struct extent_buffer
*mid
;
1887 struct extent_buffer
*left
= NULL
;
1888 struct extent_buffer
*parent
= NULL
;
1892 int orig_slot
= path
->slots
[level
];
1898 mid
= path
->nodes
[level
];
1900 WARN_ON(path
->locks
[level
] != BTRFS_WRITE_LOCK
&&
1901 path
->locks
[level
] != BTRFS_WRITE_LOCK_BLOCKING
);
1902 WARN_ON(btrfs_header_generation(mid
) != trans
->transid
);
1904 orig_ptr
= btrfs_node_blockptr(mid
, orig_slot
);
1906 if (level
< BTRFS_MAX_LEVEL
- 1) {
1907 parent
= path
->nodes
[level
+ 1];
1908 pslot
= path
->slots
[level
+ 1];
1912 * deal with the case where there is only one pointer in the root
1913 * by promoting the node below to a root
1916 struct extent_buffer
*child
;
1918 if (btrfs_header_nritems(mid
) != 1)
1921 /* promote the child to a root */
1922 child
= read_node_slot(root
, mid
, 0);
1925 btrfs_std_error(root
->fs_info
, ret
);
1929 btrfs_tree_lock(child
);
1930 btrfs_set_lock_blocking(child
);
1931 ret
= btrfs_cow_block(trans
, root
, child
, mid
, 0, &child
);
1933 btrfs_tree_unlock(child
);
1934 free_extent_buffer(child
);
1938 tree_mod_log_set_root_pointer(root
, child
, 1);
1939 rcu_assign_pointer(root
->node
, child
);
1941 add_root_to_dirty_list(root
);
1942 btrfs_tree_unlock(child
);
1944 path
->locks
[level
] = 0;
1945 path
->nodes
[level
] = NULL
;
1946 clean_tree_block(trans
, root
, mid
);
1947 btrfs_tree_unlock(mid
);
1948 /* once for the path */
1949 free_extent_buffer(mid
);
1951 root_sub_used(root
, mid
->len
);
1952 btrfs_free_tree_block(trans
, root
, mid
, 0, 1);
1953 /* once for the root ptr */
1954 free_extent_buffer_stale(mid
);
1957 if (btrfs_header_nritems(mid
) >
1958 BTRFS_NODEPTRS_PER_BLOCK(root
) / 4)
1961 left
= read_node_slot(root
, parent
, pslot
- 1);
1963 btrfs_tree_lock(left
);
1964 btrfs_set_lock_blocking(left
);
1965 wret
= btrfs_cow_block(trans
, root
, left
,
1966 parent
, pslot
- 1, &left
);
1972 right
= read_node_slot(root
, parent
, pslot
+ 1);
1974 btrfs_tree_lock(right
);
1975 btrfs_set_lock_blocking(right
);
1976 wret
= btrfs_cow_block(trans
, root
, right
,
1977 parent
, pslot
+ 1, &right
);
1984 /* first, try to make some room in the middle buffer */
1986 orig_slot
+= btrfs_header_nritems(left
);
1987 wret
= push_node_left(trans
, root
, left
, mid
, 1);
1993 * then try to empty the right most buffer into the middle
1996 wret
= push_node_left(trans
, root
, mid
, right
, 1);
1997 if (wret
< 0 && wret
!= -ENOSPC
)
1999 if (btrfs_header_nritems(right
) == 0) {
2000 clean_tree_block(trans
, root
, right
);
2001 btrfs_tree_unlock(right
);
2002 del_ptr(root
, path
, level
+ 1, pslot
+ 1);
2003 root_sub_used(root
, right
->len
);
2004 btrfs_free_tree_block(trans
, root
, right
, 0, 1);
2005 free_extent_buffer_stale(right
);
2008 struct btrfs_disk_key right_key
;
2009 btrfs_node_key(right
, &right_key
, 0);
2010 tree_mod_log_set_node_key(root
->fs_info
, parent
,
2012 btrfs_set_node_key(parent
, &right_key
, pslot
+ 1);
2013 btrfs_mark_buffer_dirty(parent
);
2016 if (btrfs_header_nritems(mid
) == 1) {
2018 * we're not allowed to leave a node with one item in the
2019 * tree during a delete. A deletion from lower in the tree
2020 * could try to delete the only pointer in this node.
2021 * So, pull some keys from the left.
2022 * There has to be a left pointer at this point because
2023 * otherwise we would have pulled some pointers from the
2028 btrfs_std_error(root
->fs_info
, ret
);
2031 wret
= balance_node_right(trans
, root
, mid
, left
);
2037 wret
= push_node_left(trans
, root
, left
, mid
, 1);
2043 if (btrfs_header_nritems(mid
) == 0) {
2044 clean_tree_block(trans
, root
, mid
);
2045 btrfs_tree_unlock(mid
);
2046 del_ptr(root
, path
, level
+ 1, pslot
);
2047 root_sub_used(root
, mid
->len
);
2048 btrfs_free_tree_block(trans
, root
, mid
, 0, 1);
2049 free_extent_buffer_stale(mid
);
2052 /* update the parent key to reflect our changes */
2053 struct btrfs_disk_key mid_key
;
2054 btrfs_node_key(mid
, &mid_key
, 0);
2055 tree_mod_log_set_node_key(root
->fs_info
, parent
,
2057 btrfs_set_node_key(parent
, &mid_key
, pslot
);
2058 btrfs_mark_buffer_dirty(parent
);
2061 /* update the path */
2063 if (btrfs_header_nritems(left
) > orig_slot
) {
2064 extent_buffer_get(left
);
2065 /* left was locked after cow */
2066 path
->nodes
[level
] = left
;
2067 path
->slots
[level
+ 1] -= 1;
2068 path
->slots
[level
] = orig_slot
;
2070 btrfs_tree_unlock(mid
);
2071 free_extent_buffer(mid
);
2074 orig_slot
-= btrfs_header_nritems(left
);
2075 path
->slots
[level
] = orig_slot
;
2078 /* double check we haven't messed things up */
2080 btrfs_node_blockptr(path
->nodes
[level
], path
->slots
[level
]))
2084 btrfs_tree_unlock(right
);
2085 free_extent_buffer(right
);
2088 if (path
->nodes
[level
] != left
)
2089 btrfs_tree_unlock(left
);
2090 free_extent_buffer(left
);
2095 /* Node balancing for insertion. Here we only split or push nodes around
2096 * when they are completely full. This is also done top down, so we
2097 * have to be pessimistic.
2099 static noinline
int push_nodes_for_insert(struct btrfs_trans_handle
*trans
,
2100 struct btrfs_root
*root
,
2101 struct btrfs_path
*path
, int level
)
2103 struct extent_buffer
*right
= NULL
;
2104 struct extent_buffer
*mid
;
2105 struct extent_buffer
*left
= NULL
;
2106 struct extent_buffer
*parent
= NULL
;
2110 int orig_slot
= path
->slots
[level
];
2115 mid
= path
->nodes
[level
];
2116 WARN_ON(btrfs_header_generation(mid
) != trans
->transid
);
2118 if (level
< BTRFS_MAX_LEVEL
- 1) {
2119 parent
= path
->nodes
[level
+ 1];
2120 pslot
= path
->slots
[level
+ 1];
2126 left
= read_node_slot(root
, parent
, pslot
- 1);
2128 /* first, try to make some room in the middle buffer */
2132 btrfs_tree_lock(left
);
2133 btrfs_set_lock_blocking(left
);
2135 left_nr
= btrfs_header_nritems(left
);
2136 if (left_nr
>= BTRFS_NODEPTRS_PER_BLOCK(root
) - 1) {
2139 ret
= btrfs_cow_block(trans
, root
, left
, parent
,
2144 wret
= push_node_left(trans
, root
,
2151 struct btrfs_disk_key disk_key
;
2152 orig_slot
+= left_nr
;
2153 btrfs_node_key(mid
, &disk_key
, 0);
2154 tree_mod_log_set_node_key(root
->fs_info
, parent
,
2156 btrfs_set_node_key(parent
, &disk_key
, pslot
);
2157 btrfs_mark_buffer_dirty(parent
);
2158 if (btrfs_header_nritems(left
) > orig_slot
) {
2159 path
->nodes
[level
] = left
;
2160 path
->slots
[level
+ 1] -= 1;
2161 path
->slots
[level
] = orig_slot
;
2162 btrfs_tree_unlock(mid
);
2163 free_extent_buffer(mid
);
2166 btrfs_header_nritems(left
);
2167 path
->slots
[level
] = orig_slot
;
2168 btrfs_tree_unlock(left
);
2169 free_extent_buffer(left
);
2173 btrfs_tree_unlock(left
);
2174 free_extent_buffer(left
);
2176 right
= read_node_slot(root
, parent
, pslot
+ 1);
2179 * then try to empty the right most buffer into the middle
2184 btrfs_tree_lock(right
);
2185 btrfs_set_lock_blocking(right
);
2187 right_nr
= btrfs_header_nritems(right
);
2188 if (right_nr
>= BTRFS_NODEPTRS_PER_BLOCK(root
) - 1) {
2191 ret
= btrfs_cow_block(trans
, root
, right
,
2197 wret
= balance_node_right(trans
, root
,
2204 struct btrfs_disk_key disk_key
;
2206 btrfs_node_key(right
, &disk_key
, 0);
2207 tree_mod_log_set_node_key(root
->fs_info
, parent
,
2209 btrfs_set_node_key(parent
, &disk_key
, pslot
+ 1);
2210 btrfs_mark_buffer_dirty(parent
);
2212 if (btrfs_header_nritems(mid
) <= orig_slot
) {
2213 path
->nodes
[level
] = right
;
2214 path
->slots
[level
+ 1] += 1;
2215 path
->slots
[level
] = orig_slot
-
2216 btrfs_header_nritems(mid
);
2217 btrfs_tree_unlock(mid
);
2218 free_extent_buffer(mid
);
2220 btrfs_tree_unlock(right
);
2221 free_extent_buffer(right
);
2225 btrfs_tree_unlock(right
);
2226 free_extent_buffer(right
);
2232 * readahead one full node of leaves, finding things that are close
2233 * to the block in 'slot', and triggering ra on them.
2235 static void reada_for_search(struct btrfs_root
*root
,
2236 struct btrfs_path
*path
,
2237 int level
, int slot
, u64 objectid
)
2239 struct extent_buffer
*node
;
2240 struct btrfs_disk_key disk_key
;
2246 int direction
= path
->reada
;
2247 struct extent_buffer
*eb
;
2255 if (!path
->nodes
[level
])
2258 node
= path
->nodes
[level
];
2260 search
= btrfs_node_blockptr(node
, slot
);
2261 blocksize
= root
->nodesize
;
2262 eb
= btrfs_find_tree_block(root
, search
);
2264 free_extent_buffer(eb
);
2270 nritems
= btrfs_header_nritems(node
);
2274 if (direction
< 0) {
2278 } else if (direction
> 0) {
2283 if (path
->reada
< 0 && objectid
) {
2284 btrfs_node_key(node
, &disk_key
, nr
);
2285 if (btrfs_disk_key_objectid(&disk_key
) != objectid
)
2288 search
= btrfs_node_blockptr(node
, nr
);
2289 if ((search
<= target
&& target
- search
<= 65536) ||
2290 (search
> target
&& search
- target
<= 65536)) {
2291 gen
= btrfs_node_ptr_generation(node
, nr
);
2292 readahead_tree_block(root
, search
);
2296 if ((nread
> 65536 || nscan
> 32))
2301 static noinline
void reada_for_balance(struct btrfs_root
*root
,
2302 struct btrfs_path
*path
, int level
)
2306 struct extent_buffer
*parent
;
2307 struct extent_buffer
*eb
;
2312 parent
= path
->nodes
[level
+ 1];
2316 nritems
= btrfs_header_nritems(parent
);
2317 slot
= path
->slots
[level
+ 1];
2320 block1
= btrfs_node_blockptr(parent
, slot
- 1);
2321 gen
= btrfs_node_ptr_generation(parent
, slot
- 1);
2322 eb
= btrfs_find_tree_block(root
, block1
);
2324 * if we get -eagain from btrfs_buffer_uptodate, we
2325 * don't want to return eagain here. That will loop
2328 if (eb
&& btrfs_buffer_uptodate(eb
, gen
, 1) != 0)
2330 free_extent_buffer(eb
);
2332 if (slot
+ 1 < nritems
) {
2333 block2
= btrfs_node_blockptr(parent
, slot
+ 1);
2334 gen
= btrfs_node_ptr_generation(parent
, slot
+ 1);
2335 eb
= btrfs_find_tree_block(root
, block2
);
2336 if (eb
&& btrfs_buffer_uptodate(eb
, gen
, 1) != 0)
2338 free_extent_buffer(eb
);
2342 readahead_tree_block(root
, block1
);
2344 readahead_tree_block(root
, block2
);
2349 * when we walk down the tree, it is usually safe to unlock the higher layers
2350 * in the tree. The exceptions are when our path goes through slot 0, because
2351 * operations on the tree might require changing key pointers higher up in the
2354 * callers might also have set path->keep_locks, which tells this code to keep
2355 * the lock if the path points to the last slot in the block. This is part of
2356 * walking through the tree, and selecting the next slot in the higher block.
2358 * lowest_unlock sets the lowest level in the tree we're allowed to unlock. so
2359 * if lowest_unlock is 1, level 0 won't be unlocked
2361 static noinline
void unlock_up(struct btrfs_path
*path
, int level
,
2362 int lowest_unlock
, int min_write_lock_level
,
2363 int *write_lock_level
)
2366 int skip_level
= level
;
2368 struct extent_buffer
*t
;
2370 for (i
= level
; i
< BTRFS_MAX_LEVEL
; i
++) {
2371 if (!path
->nodes
[i
])
2373 if (!path
->locks
[i
])
2375 if (!no_skips
&& path
->slots
[i
] == 0) {
2379 if (!no_skips
&& path
->keep_locks
) {
2382 nritems
= btrfs_header_nritems(t
);
2383 if (nritems
< 1 || path
->slots
[i
] >= nritems
- 1) {
2388 if (skip_level
< i
&& i
>= lowest_unlock
)
2392 if (i
>= lowest_unlock
&& i
> skip_level
&& path
->locks
[i
]) {
2393 btrfs_tree_unlock_rw(t
, path
->locks
[i
]);
2395 if (write_lock_level
&&
2396 i
> min_write_lock_level
&&
2397 i
<= *write_lock_level
) {
2398 *write_lock_level
= i
- 1;
2405 * This releases any locks held in the path starting at level and
2406 * going all the way up to the root.
2408 * btrfs_search_slot will keep the lock held on higher nodes in a few
2409 * corner cases, such as COW of the block at slot zero in the node. This
2410 * ignores those rules, and it should only be called when there are no
2411 * more updates to be done higher up in the tree.
2413 noinline
void btrfs_unlock_up_safe(struct btrfs_path
*path
, int level
)
2417 if (path
->keep_locks
)
2420 for (i
= level
; i
< BTRFS_MAX_LEVEL
; i
++) {
2421 if (!path
->nodes
[i
])
2423 if (!path
->locks
[i
])
2425 btrfs_tree_unlock_rw(path
->nodes
[i
], path
->locks
[i
]);
2431 * helper function for btrfs_search_slot. The goal is to find a block
2432 * in cache without setting the path to blocking. If we find the block
2433 * we return zero and the path is unchanged.
2435 * If we can't find the block, we set the path blocking and do some
2436 * reada. -EAGAIN is returned and the search must be repeated.
2439 read_block_for_search(struct btrfs_trans_handle
*trans
,
2440 struct btrfs_root
*root
, struct btrfs_path
*p
,
2441 struct extent_buffer
**eb_ret
, int level
, int slot
,
2442 struct btrfs_key
*key
, u64 time_seq
)
2446 struct extent_buffer
*b
= *eb_ret
;
2447 struct extent_buffer
*tmp
;
2450 blocknr
= btrfs_node_blockptr(b
, slot
);
2451 gen
= btrfs_node_ptr_generation(b
, slot
);
2453 tmp
= btrfs_find_tree_block(root
, blocknr
);
2455 /* first we do an atomic uptodate check */
2456 if (btrfs_buffer_uptodate(tmp
, gen
, 1) > 0) {
2461 /* the pages were up to date, but we failed
2462 * the generation number check. Do a full
2463 * read for the generation number that is correct.
2464 * We must do this without dropping locks so
2465 * we can trust our generation number
2467 btrfs_set_path_blocking(p
);
2469 /* now we're allowed to do a blocking uptodate check */
2470 ret
= btrfs_read_buffer(tmp
, gen
);
2475 free_extent_buffer(tmp
);
2476 btrfs_release_path(p
);
2481 * reduce lock contention at high levels
2482 * of the btree by dropping locks before
2483 * we read. Don't release the lock on the current
2484 * level because we need to walk this node to figure
2485 * out which blocks to read.
2487 btrfs_unlock_up_safe(p
, level
+ 1);
2488 btrfs_set_path_blocking(p
);
2490 free_extent_buffer(tmp
);
2492 reada_for_search(root
, p
, level
, slot
, key
->objectid
);
2494 btrfs_release_path(p
);
2497 tmp
= read_tree_block(root
, blocknr
, 0);
2500 * If the read above didn't mark this buffer up to date,
2501 * it will never end up being up to date. Set ret to EIO now
2502 * and give up so that our caller doesn't loop forever
2505 if (!btrfs_buffer_uptodate(tmp
, 0, 0))
2507 free_extent_buffer(tmp
);
2513 * helper function for btrfs_search_slot. This does all of the checks
2514 * for node-level blocks and does any balancing required based on
2517 * If no extra work was required, zero is returned. If we had to
2518 * drop the path, -EAGAIN is returned and btrfs_search_slot must
2522 setup_nodes_for_search(struct btrfs_trans_handle
*trans
,
2523 struct btrfs_root
*root
, struct btrfs_path
*p
,
2524 struct extent_buffer
*b
, int level
, int ins_len
,
2525 int *write_lock_level
)
2528 if ((p
->search_for_split
|| ins_len
> 0) && btrfs_header_nritems(b
) >=
2529 BTRFS_NODEPTRS_PER_BLOCK(root
) - 3) {
2532 if (*write_lock_level
< level
+ 1) {
2533 *write_lock_level
= level
+ 1;
2534 btrfs_release_path(p
);
2538 btrfs_set_path_blocking(p
);
2539 reada_for_balance(root
, p
, level
);
2540 sret
= split_node(trans
, root
, p
, level
);
2541 btrfs_clear_path_blocking(p
, NULL
, 0);
2548 b
= p
->nodes
[level
];
2549 } else if (ins_len
< 0 && btrfs_header_nritems(b
) <
2550 BTRFS_NODEPTRS_PER_BLOCK(root
) / 2) {
2553 if (*write_lock_level
< level
+ 1) {
2554 *write_lock_level
= level
+ 1;
2555 btrfs_release_path(p
);
2559 btrfs_set_path_blocking(p
);
2560 reada_for_balance(root
, p
, level
);
2561 sret
= balance_level(trans
, root
, p
, level
);
2562 btrfs_clear_path_blocking(p
, NULL
, 0);
2568 b
= p
->nodes
[level
];
2570 btrfs_release_path(p
);
2573 BUG_ON(btrfs_header_nritems(b
) == 1);
2583 static void key_search_validate(struct extent_buffer
*b
,
2584 struct btrfs_key
*key
,
2587 #ifdef CONFIG_BTRFS_ASSERT
2588 struct btrfs_disk_key disk_key
;
2590 btrfs_cpu_key_to_disk(&disk_key
, key
);
2593 ASSERT(!memcmp_extent_buffer(b
, &disk_key
,
2594 offsetof(struct btrfs_leaf
, items
[0].key
),
2597 ASSERT(!memcmp_extent_buffer(b
, &disk_key
,
2598 offsetof(struct btrfs_node
, ptrs
[0].key
),
2603 static int key_search(struct extent_buffer
*b
, struct btrfs_key
*key
,
2604 int level
, int *prev_cmp
, int *slot
)
2606 if (*prev_cmp
!= 0) {
2607 *prev_cmp
= bin_search(b
, key
, level
, slot
);
2611 key_search_validate(b
, key
, level
);
2617 int btrfs_find_item(struct btrfs_root
*fs_root
, struct btrfs_path
*path
,
2618 u64 iobjectid
, u64 ioff
, u8 key_type
,
2619 struct btrfs_key
*found_key
)
2622 struct btrfs_key key
;
2623 struct extent_buffer
*eb
;
2628 key
.type
= key_type
;
2629 key
.objectid
= iobjectid
;
2632 ret
= btrfs_search_slot(NULL
, fs_root
, &key
, path
, 0, 0);
2636 eb
= path
->nodes
[0];
2637 if (ret
&& path
->slots
[0] >= btrfs_header_nritems(eb
)) {
2638 ret
= btrfs_next_leaf(fs_root
, path
);
2641 eb
= path
->nodes
[0];
2644 btrfs_item_key_to_cpu(eb
, found_key
, path
->slots
[0]);
2645 if (found_key
->type
!= key
.type
||
2646 found_key
->objectid
!= key
.objectid
)
2653 * look for key in the tree. path is filled in with nodes along the way
2654 * if key is found, we return zero and you can find the item in the leaf
2655 * level of the path (level 0)
2657 * If the key isn't found, the path points to the slot where it should
2658 * be inserted, and 1 is returned. If there are other errors during the
2659 * search a negative error number is returned.
2661 * if ins_len > 0, nodes and leaves will be split as we walk down the
2662 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
2665 int btrfs_search_slot(struct btrfs_trans_handle
*trans
, struct btrfs_root
2666 *root
, struct btrfs_key
*key
, struct btrfs_path
*p
, int
2669 struct extent_buffer
*b
;
2674 int lowest_unlock
= 1;
2676 /* everything at write_lock_level or lower must be write locked */
2677 int write_lock_level
= 0;
2678 u8 lowest_level
= 0;
2679 int min_write_lock_level
;
2682 lowest_level
= p
->lowest_level
;
2683 WARN_ON(lowest_level
&& ins_len
> 0);
2684 WARN_ON(p
->nodes
[0] != NULL
);
2685 BUG_ON(!cow
&& ins_len
);
2690 /* when we are removing items, we might have to go up to level
2691 * two as we update tree pointers Make sure we keep write
2692 * for those levels as well
2694 write_lock_level
= 2;
2695 } else if (ins_len
> 0) {
2697 * for inserting items, make sure we have a write lock on
2698 * level 1 so we can update keys
2700 write_lock_level
= 1;
2704 write_lock_level
= -1;
2706 if (cow
&& (p
->keep_locks
|| p
->lowest_level
))
2707 write_lock_level
= BTRFS_MAX_LEVEL
;
2709 min_write_lock_level
= write_lock_level
;
2714 * we try very hard to do read locks on the root
2716 root_lock
= BTRFS_READ_LOCK
;
2718 if (p
->search_commit_root
) {
2720 * the commit roots are read only
2721 * so we always do read locks
2723 if (p
->need_commit_sem
)
2724 down_read(&root
->fs_info
->commit_root_sem
);
2725 b
= root
->commit_root
;
2726 extent_buffer_get(b
);
2727 level
= btrfs_header_level(b
);
2728 if (p
->need_commit_sem
)
2729 up_read(&root
->fs_info
->commit_root_sem
);
2730 if (!p
->skip_locking
)
2731 btrfs_tree_read_lock(b
);
2733 if (p
->skip_locking
) {
2734 b
= btrfs_root_node(root
);
2735 level
= btrfs_header_level(b
);
2737 /* we don't know the level of the root node
2738 * until we actually have it read locked
2740 b
= btrfs_read_lock_root_node(root
);
2741 level
= btrfs_header_level(b
);
2742 if (level
<= write_lock_level
) {
2743 /* whoops, must trade for write lock */
2744 btrfs_tree_read_unlock(b
);
2745 free_extent_buffer(b
);
2746 b
= btrfs_lock_root_node(root
);
2747 root_lock
= BTRFS_WRITE_LOCK
;
2749 /* the level might have changed, check again */
2750 level
= btrfs_header_level(b
);
2754 p
->nodes
[level
] = b
;
2755 if (!p
->skip_locking
)
2756 p
->locks
[level
] = root_lock
;
2759 level
= btrfs_header_level(b
);
2762 * setup the path here so we can release it under lock
2763 * contention with the cow code
2767 * if we don't really need to cow this block
2768 * then we don't want to set the path blocking,
2769 * so we test it here
2771 if (!should_cow_block(trans
, root
, b
))
2775 * must have write locks on this node and the
2778 if (level
> write_lock_level
||
2779 (level
+ 1 > write_lock_level
&&
2780 level
+ 1 < BTRFS_MAX_LEVEL
&&
2781 p
->nodes
[level
+ 1])) {
2782 write_lock_level
= level
+ 1;
2783 btrfs_release_path(p
);
2787 btrfs_set_path_blocking(p
);
2788 err
= btrfs_cow_block(trans
, root
, b
,
2789 p
->nodes
[level
+ 1],
2790 p
->slots
[level
+ 1], &b
);
2797 p
->nodes
[level
] = b
;
2798 btrfs_clear_path_blocking(p
, NULL
, 0);
2801 * we have a lock on b and as long as we aren't changing
2802 * the tree, there is no way to for the items in b to change.
2803 * It is safe to drop the lock on our parent before we
2804 * go through the expensive btree search on b.
2806 * If we're inserting or deleting (ins_len != 0), then we might
2807 * be changing slot zero, which may require changing the parent.
2808 * So, we can't drop the lock until after we know which slot
2809 * we're operating on.
2811 if (!ins_len
&& !p
->keep_locks
) {
2814 if (u
< BTRFS_MAX_LEVEL
&& p
->locks
[u
]) {
2815 btrfs_tree_unlock_rw(p
->nodes
[u
], p
->locks
[u
]);
2820 ret
= key_search(b
, key
, level
, &prev_cmp
, &slot
);
2824 if (ret
&& slot
> 0) {
2828 p
->slots
[level
] = slot
;
2829 err
= setup_nodes_for_search(trans
, root
, p
, b
, level
,
2830 ins_len
, &write_lock_level
);
2837 b
= p
->nodes
[level
];
2838 slot
= p
->slots
[level
];
2841 * slot 0 is special, if we change the key
2842 * we have to update the parent pointer
2843 * which means we must have a write lock
2846 if (slot
== 0 && ins_len
&&
2847 write_lock_level
< level
+ 1) {
2848 write_lock_level
= level
+ 1;
2849 btrfs_release_path(p
);
2853 unlock_up(p
, level
, lowest_unlock
,
2854 min_write_lock_level
, &write_lock_level
);
2856 if (level
== lowest_level
) {
2862 err
= read_block_for_search(trans
, root
, p
,
2863 &b
, level
, slot
, key
, 0);
2871 if (!p
->skip_locking
) {
2872 level
= btrfs_header_level(b
);
2873 if (level
<= write_lock_level
) {
2874 err
= btrfs_try_tree_write_lock(b
);
2876 btrfs_set_path_blocking(p
);
2878 btrfs_clear_path_blocking(p
, b
,
2881 p
->locks
[level
] = BTRFS_WRITE_LOCK
;
2883 err
= btrfs_tree_read_lock_atomic(b
);
2885 btrfs_set_path_blocking(p
);
2886 btrfs_tree_read_lock(b
);
2887 btrfs_clear_path_blocking(p
, b
,
2890 p
->locks
[level
] = BTRFS_READ_LOCK
;
2892 p
->nodes
[level
] = b
;
2895 p
->slots
[level
] = slot
;
2897 btrfs_leaf_free_space(root
, b
) < ins_len
) {
2898 if (write_lock_level
< 1) {
2899 write_lock_level
= 1;
2900 btrfs_release_path(p
);
2904 btrfs_set_path_blocking(p
);
2905 err
= split_leaf(trans
, root
, key
,
2906 p
, ins_len
, ret
== 0);
2907 btrfs_clear_path_blocking(p
, NULL
, 0);
2915 if (!p
->search_for_split
)
2916 unlock_up(p
, level
, lowest_unlock
,
2917 min_write_lock_level
, &write_lock_level
);
2924 * we don't really know what they plan on doing with the path
2925 * from here on, so for now just mark it as blocking
2927 if (!p
->leave_spinning
)
2928 btrfs_set_path_blocking(p
);
2929 if (ret
< 0 && !p
->skip_release_on_error
)
2930 btrfs_release_path(p
);
2935 * Like btrfs_search_slot, this looks for a key in the given tree. It uses the
2936 * current state of the tree together with the operations recorded in the tree
2937 * modification log to search for the key in a previous version of this tree, as
2938 * denoted by the time_seq parameter.
2940 * Naturally, there is no support for insert, delete or cow operations.
2942 * The resulting path and return value will be set up as if we called
2943 * btrfs_search_slot at that point in time with ins_len and cow both set to 0.
2945 int btrfs_search_old_slot(struct btrfs_root
*root
, struct btrfs_key
*key
,
2946 struct btrfs_path
*p
, u64 time_seq
)
2948 struct extent_buffer
*b
;
2953 int lowest_unlock
= 1;
2954 u8 lowest_level
= 0;
2957 lowest_level
= p
->lowest_level
;
2958 WARN_ON(p
->nodes
[0] != NULL
);
2960 if (p
->search_commit_root
) {
2962 return btrfs_search_slot(NULL
, root
, key
, p
, 0, 0);
2966 b
= get_old_root(root
, time_seq
);
2967 level
= btrfs_header_level(b
);
2968 p
->locks
[level
] = BTRFS_READ_LOCK
;
2971 level
= btrfs_header_level(b
);
2972 p
->nodes
[level
] = b
;
2973 btrfs_clear_path_blocking(p
, NULL
, 0);
2976 * we have a lock on b and as long as we aren't changing
2977 * the tree, there is no way to for the items in b to change.
2978 * It is safe to drop the lock on our parent before we
2979 * go through the expensive btree search on b.
2981 btrfs_unlock_up_safe(p
, level
+ 1);
2984 * Since we can unwind eb's we want to do a real search every
2988 ret
= key_search(b
, key
, level
, &prev_cmp
, &slot
);
2992 if (ret
&& slot
> 0) {
2996 p
->slots
[level
] = slot
;
2997 unlock_up(p
, level
, lowest_unlock
, 0, NULL
);
2999 if (level
== lowest_level
) {
3005 err
= read_block_for_search(NULL
, root
, p
, &b
, level
,
3006 slot
, key
, time_seq
);
3014 level
= btrfs_header_level(b
);
3015 err
= btrfs_tree_read_lock_atomic(b
);
3017 btrfs_set_path_blocking(p
);
3018 btrfs_tree_read_lock(b
);
3019 btrfs_clear_path_blocking(p
, b
,
3022 b
= tree_mod_log_rewind(root
->fs_info
, p
, b
, time_seq
);
3027 p
->locks
[level
] = BTRFS_READ_LOCK
;
3028 p
->nodes
[level
] = b
;
3030 p
->slots
[level
] = slot
;
3031 unlock_up(p
, level
, lowest_unlock
, 0, NULL
);
3037 if (!p
->leave_spinning
)
3038 btrfs_set_path_blocking(p
);
3040 btrfs_release_path(p
);
3046 * helper to use instead of search slot if no exact match is needed but
3047 * instead the next or previous item should be returned.
3048 * When find_higher is true, the next higher item is returned, the next lower
3050 * When return_any and find_higher are both true, and no higher item is found,
3051 * return the next lower instead.
3052 * When return_any is true and find_higher is false, and no lower item is found,
3053 * return the next higher instead.
3054 * It returns 0 if any item is found, 1 if none is found (tree empty), and
3057 int btrfs_search_slot_for_read(struct btrfs_root
*root
,
3058 struct btrfs_key
*key
, struct btrfs_path
*p
,
3059 int find_higher
, int return_any
)
3062 struct extent_buffer
*leaf
;
3065 ret
= btrfs_search_slot(NULL
, root
, key
, p
, 0, 0);
3069 * a return value of 1 means the path is at the position where the
3070 * item should be inserted. Normally this is the next bigger item,
3071 * but in case the previous item is the last in a leaf, path points
3072 * to the first free slot in the previous leaf, i.e. at an invalid
3078 if (p
->slots
[0] >= btrfs_header_nritems(leaf
)) {
3079 ret
= btrfs_next_leaf(root
, p
);
3085 * no higher item found, return the next
3090 btrfs_release_path(p
);
3094 if (p
->slots
[0] == 0) {
3095 ret
= btrfs_prev_leaf(root
, p
);
3100 if (p
->slots
[0] == btrfs_header_nritems(leaf
))
3107 * no lower item found, return the next
3112 btrfs_release_path(p
);
3122 * adjust the pointers going up the tree, starting at level
3123 * making sure the right key of each node is points to 'key'.
3124 * This is used after shifting pointers to the left, so it stops
3125 * fixing up pointers when a given leaf/node is not in slot 0 of the
3129 static void fixup_low_keys(struct btrfs_root
*root
, struct btrfs_path
*path
,
3130 struct btrfs_disk_key
*key
, int level
)
3133 struct extent_buffer
*t
;
3135 for (i
= level
; i
< BTRFS_MAX_LEVEL
; i
++) {
3136 int tslot
= path
->slots
[i
];
3137 if (!path
->nodes
[i
])
3140 tree_mod_log_set_node_key(root
->fs_info
, t
, tslot
, 1);
3141 btrfs_set_node_key(t
, key
, tslot
);
3142 btrfs_mark_buffer_dirty(path
->nodes
[i
]);
3151 * This function isn't completely safe. It's the caller's responsibility
3152 * that the new key won't break the order
3154 void btrfs_set_item_key_safe(struct btrfs_root
*root
, struct btrfs_path
*path
,
3155 struct btrfs_key
*new_key
)
3157 struct btrfs_disk_key disk_key
;
3158 struct extent_buffer
*eb
;
3161 eb
= path
->nodes
[0];
3162 slot
= path
->slots
[0];
3164 btrfs_item_key(eb
, &disk_key
, slot
- 1);
3165 BUG_ON(comp_keys(&disk_key
, new_key
) >= 0);
3167 if (slot
< btrfs_header_nritems(eb
) - 1) {
3168 btrfs_item_key(eb
, &disk_key
, slot
+ 1);
3169 BUG_ON(comp_keys(&disk_key
, new_key
) <= 0);
3172 btrfs_cpu_key_to_disk(&disk_key
, new_key
);
3173 btrfs_set_item_key(eb
, &disk_key
, slot
);
3174 btrfs_mark_buffer_dirty(eb
);
3176 fixup_low_keys(root
, path
, &disk_key
, 1);
3180 * try to push data from one node into the next node left in the
3183 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
3184 * error, and > 0 if there was no room in the left hand block.
3186 static int push_node_left(struct btrfs_trans_handle
*trans
,
3187 struct btrfs_root
*root
, struct extent_buffer
*dst
,
3188 struct extent_buffer
*src
, int empty
)
3195 src_nritems
= btrfs_header_nritems(src
);
3196 dst_nritems
= btrfs_header_nritems(dst
);
3197 push_items
= BTRFS_NODEPTRS_PER_BLOCK(root
) - dst_nritems
;
3198 WARN_ON(btrfs_header_generation(src
) != trans
->transid
);
3199 WARN_ON(btrfs_header_generation(dst
) != trans
->transid
);
3201 if (!empty
&& src_nritems
<= 8)
3204 if (push_items
<= 0)
3208 push_items
= min(src_nritems
, push_items
);
3209 if (push_items
< src_nritems
) {
3210 /* leave at least 8 pointers in the node if
3211 * we aren't going to empty it
3213 if (src_nritems
- push_items
< 8) {
3214 if (push_items
<= 8)
3220 push_items
= min(src_nritems
- 8, push_items
);
3222 ret
= tree_mod_log_eb_copy(root
->fs_info
, dst
, src
, dst_nritems
, 0,
3225 btrfs_abort_transaction(trans
, root
, ret
);
3228 copy_extent_buffer(dst
, src
,
3229 btrfs_node_key_ptr_offset(dst_nritems
),
3230 btrfs_node_key_ptr_offset(0),
3231 push_items
* sizeof(struct btrfs_key_ptr
));
3233 if (push_items
< src_nritems
) {
3235 * don't call tree_mod_log_eb_move here, key removal was already
3236 * fully logged by tree_mod_log_eb_copy above.
3238 memmove_extent_buffer(src
, btrfs_node_key_ptr_offset(0),
3239 btrfs_node_key_ptr_offset(push_items
),
3240 (src_nritems
- push_items
) *
3241 sizeof(struct btrfs_key_ptr
));
3243 btrfs_set_header_nritems(src
, src_nritems
- push_items
);
3244 btrfs_set_header_nritems(dst
, dst_nritems
+ push_items
);
3245 btrfs_mark_buffer_dirty(src
);
3246 btrfs_mark_buffer_dirty(dst
);
3252 * try to push data from one node into the next node right in the
3255 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
3256 * error, and > 0 if there was no room in the right hand block.
3258 * this will only push up to 1/2 the contents of the left node over
3260 static int balance_node_right(struct btrfs_trans_handle
*trans
,
3261 struct btrfs_root
*root
,
3262 struct extent_buffer
*dst
,
3263 struct extent_buffer
*src
)
3271 WARN_ON(btrfs_header_generation(src
) != trans
->transid
);
3272 WARN_ON(btrfs_header_generation(dst
) != trans
->transid
);
3274 src_nritems
= btrfs_header_nritems(src
);
3275 dst_nritems
= btrfs_header_nritems(dst
);
3276 push_items
= BTRFS_NODEPTRS_PER_BLOCK(root
) - dst_nritems
;
3277 if (push_items
<= 0)
3280 if (src_nritems
< 4)
3283 max_push
= src_nritems
/ 2 + 1;
3284 /* don't try to empty the node */
3285 if (max_push
>= src_nritems
)
3288 if (max_push
< push_items
)
3289 push_items
= max_push
;
3291 tree_mod_log_eb_move(root
->fs_info
, dst
, push_items
, 0, dst_nritems
);
3292 memmove_extent_buffer(dst
, btrfs_node_key_ptr_offset(push_items
),
3293 btrfs_node_key_ptr_offset(0),
3295 sizeof(struct btrfs_key_ptr
));
3297 ret
= tree_mod_log_eb_copy(root
->fs_info
, dst
, src
, 0,
3298 src_nritems
- push_items
, push_items
);
3300 btrfs_abort_transaction(trans
, root
, ret
);
3303 copy_extent_buffer(dst
, src
,
3304 btrfs_node_key_ptr_offset(0),
3305 btrfs_node_key_ptr_offset(src_nritems
- push_items
),
3306 push_items
* sizeof(struct btrfs_key_ptr
));
3308 btrfs_set_header_nritems(src
, src_nritems
- push_items
);
3309 btrfs_set_header_nritems(dst
, dst_nritems
+ push_items
);
3311 btrfs_mark_buffer_dirty(src
);
3312 btrfs_mark_buffer_dirty(dst
);
3318 * helper function to insert a new root level in the tree.
3319 * A new node is allocated, and a single item is inserted to
3320 * point to the existing root
3322 * returns zero on success or < 0 on failure.
3324 static noinline
int insert_new_root(struct btrfs_trans_handle
*trans
,
3325 struct btrfs_root
*root
,
3326 struct btrfs_path
*path
, int level
)
3329 struct extent_buffer
*lower
;
3330 struct extent_buffer
*c
;
3331 struct extent_buffer
*old
;
3332 struct btrfs_disk_key lower_key
;
3334 BUG_ON(path
->nodes
[level
]);
3335 BUG_ON(path
->nodes
[level
-1] != root
->node
);
3337 lower
= path
->nodes
[level
-1];
3339 btrfs_item_key(lower
, &lower_key
, 0);
3341 btrfs_node_key(lower
, &lower_key
, 0);
3343 c
= btrfs_alloc_tree_block(trans
, root
, 0, root
->root_key
.objectid
,
3344 &lower_key
, level
, root
->node
->start
, 0);
3348 root_add_used(root
, root
->nodesize
);
3350 memset_extent_buffer(c
, 0, 0, sizeof(struct btrfs_header
));
3351 btrfs_set_header_nritems(c
, 1);
3352 btrfs_set_header_level(c
, level
);
3353 btrfs_set_header_bytenr(c
, c
->start
);
3354 btrfs_set_header_generation(c
, trans
->transid
);
3355 btrfs_set_header_backref_rev(c
, BTRFS_MIXED_BACKREF_REV
);
3356 btrfs_set_header_owner(c
, root
->root_key
.objectid
);
3358 write_extent_buffer(c
, root
->fs_info
->fsid
, btrfs_header_fsid(),
3361 write_extent_buffer(c
, root
->fs_info
->chunk_tree_uuid
,
3362 btrfs_header_chunk_tree_uuid(c
), BTRFS_UUID_SIZE
);
3364 btrfs_set_node_key(c
, &lower_key
, 0);
3365 btrfs_set_node_blockptr(c
, 0, lower
->start
);
3366 lower_gen
= btrfs_header_generation(lower
);
3367 WARN_ON(lower_gen
!= trans
->transid
);
3369 btrfs_set_node_ptr_generation(c
, 0, lower_gen
);
3371 btrfs_mark_buffer_dirty(c
);
3374 tree_mod_log_set_root_pointer(root
, c
, 0);
3375 rcu_assign_pointer(root
->node
, c
);
3377 /* the super has an extra ref to root->node */
3378 free_extent_buffer(old
);
3380 add_root_to_dirty_list(root
);
3381 extent_buffer_get(c
);
3382 path
->nodes
[level
] = c
;
3383 path
->locks
[level
] = BTRFS_WRITE_LOCK_BLOCKING
;
3384 path
->slots
[level
] = 0;
3389 * worker function to insert a single pointer in a node.
3390 * the node should have enough room for the pointer already
3392 * slot and level indicate where you want the key to go, and
3393 * blocknr is the block the key points to.
3395 static void insert_ptr(struct btrfs_trans_handle
*trans
,
3396 struct btrfs_root
*root
, struct btrfs_path
*path
,
3397 struct btrfs_disk_key
*key
, u64 bytenr
,
3398 int slot
, int level
)
3400 struct extent_buffer
*lower
;
3404 BUG_ON(!path
->nodes
[level
]);
3405 btrfs_assert_tree_locked(path
->nodes
[level
]);
3406 lower
= path
->nodes
[level
];
3407 nritems
= btrfs_header_nritems(lower
);
3408 BUG_ON(slot
> nritems
);
3409 BUG_ON(nritems
== BTRFS_NODEPTRS_PER_BLOCK(root
));
3410 if (slot
!= nritems
) {
3412 tree_mod_log_eb_move(root
->fs_info
, lower
, slot
+ 1,
3413 slot
, nritems
- slot
);
3414 memmove_extent_buffer(lower
,
3415 btrfs_node_key_ptr_offset(slot
+ 1),
3416 btrfs_node_key_ptr_offset(slot
),
3417 (nritems
- slot
) * sizeof(struct btrfs_key_ptr
));
3420 ret
= tree_mod_log_insert_key(root
->fs_info
, lower
, slot
,
3421 MOD_LOG_KEY_ADD
, GFP_NOFS
);
3424 btrfs_set_node_key(lower
, key
, slot
);
3425 btrfs_set_node_blockptr(lower
, slot
, bytenr
);
3426 WARN_ON(trans
->transid
== 0);
3427 btrfs_set_node_ptr_generation(lower
, slot
, trans
->transid
);
3428 btrfs_set_header_nritems(lower
, nritems
+ 1);
3429 btrfs_mark_buffer_dirty(lower
);
3433 * split the node at the specified level in path in two.
3434 * The path is corrected to point to the appropriate node after the split
3436 * Before splitting this tries to make some room in the node by pushing
3437 * left and right, if either one works, it returns right away.
3439 * returns 0 on success and < 0 on failure
3441 static noinline
int split_node(struct btrfs_trans_handle
*trans
,
3442 struct btrfs_root
*root
,
3443 struct btrfs_path
*path
, int level
)
3445 struct extent_buffer
*c
;
3446 struct extent_buffer
*split
;
3447 struct btrfs_disk_key disk_key
;
3452 c
= path
->nodes
[level
];
3453 WARN_ON(btrfs_header_generation(c
) != trans
->transid
);
3454 if (c
== root
->node
) {
3456 * trying to split the root, lets make a new one
3458 * tree mod log: We don't log_removal old root in
3459 * insert_new_root, because that root buffer will be kept as a
3460 * normal node. We are going to log removal of half of the
3461 * elements below with tree_mod_log_eb_copy. We're holding a
3462 * tree lock on the buffer, which is why we cannot race with
3463 * other tree_mod_log users.
3465 ret
= insert_new_root(trans
, root
, path
, level
+ 1);
3469 ret
= push_nodes_for_insert(trans
, root
, path
, level
);
3470 c
= path
->nodes
[level
];
3471 if (!ret
&& btrfs_header_nritems(c
) <
3472 BTRFS_NODEPTRS_PER_BLOCK(root
) - 3)
3478 c_nritems
= btrfs_header_nritems(c
);
3479 mid
= (c_nritems
+ 1) / 2;
3480 btrfs_node_key(c
, &disk_key
, mid
);
3482 split
= btrfs_alloc_tree_block(trans
, root
, 0, root
->root_key
.objectid
,
3483 &disk_key
, level
, c
->start
, 0);
3485 return PTR_ERR(split
);
3487 root_add_used(root
, root
->nodesize
);
3489 memset_extent_buffer(split
, 0, 0, sizeof(struct btrfs_header
));
3490 btrfs_set_header_level(split
, btrfs_header_level(c
));
3491 btrfs_set_header_bytenr(split
, split
->start
);
3492 btrfs_set_header_generation(split
, trans
->transid
);
3493 btrfs_set_header_backref_rev(split
, BTRFS_MIXED_BACKREF_REV
);
3494 btrfs_set_header_owner(split
, root
->root_key
.objectid
);
3495 write_extent_buffer(split
, root
->fs_info
->fsid
,
3496 btrfs_header_fsid(), BTRFS_FSID_SIZE
);
3497 write_extent_buffer(split
, root
->fs_info
->chunk_tree_uuid
,
3498 btrfs_header_chunk_tree_uuid(split
),
3501 ret
= tree_mod_log_eb_copy(root
->fs_info
, split
, c
, 0,
3502 mid
, c_nritems
- mid
);
3504 btrfs_abort_transaction(trans
, root
, ret
);
3507 copy_extent_buffer(split
, c
,
3508 btrfs_node_key_ptr_offset(0),
3509 btrfs_node_key_ptr_offset(mid
),
3510 (c_nritems
- mid
) * sizeof(struct btrfs_key_ptr
));
3511 btrfs_set_header_nritems(split
, c_nritems
- mid
);
3512 btrfs_set_header_nritems(c
, mid
);
3515 btrfs_mark_buffer_dirty(c
);
3516 btrfs_mark_buffer_dirty(split
);
3518 insert_ptr(trans
, root
, path
, &disk_key
, split
->start
,
3519 path
->slots
[level
+ 1] + 1, level
+ 1);
3521 if (path
->slots
[level
] >= mid
) {
3522 path
->slots
[level
] -= mid
;
3523 btrfs_tree_unlock(c
);
3524 free_extent_buffer(c
);
3525 path
->nodes
[level
] = split
;
3526 path
->slots
[level
+ 1] += 1;
3528 btrfs_tree_unlock(split
);
3529 free_extent_buffer(split
);
3535 * how many bytes are required to store the items in a leaf. start
3536 * and nr indicate which items in the leaf to check. This totals up the
3537 * space used both by the item structs and the item data
3539 static int leaf_space_used(struct extent_buffer
*l
, int start
, int nr
)
3541 struct btrfs_item
*start_item
;
3542 struct btrfs_item
*end_item
;
3543 struct btrfs_map_token token
;
3545 int nritems
= btrfs_header_nritems(l
);
3546 int end
= min(nritems
, start
+ nr
) - 1;
3550 btrfs_init_map_token(&token
);
3551 start_item
= btrfs_item_nr(start
);
3552 end_item
= btrfs_item_nr(end
);
3553 data_len
= btrfs_token_item_offset(l
, start_item
, &token
) +
3554 btrfs_token_item_size(l
, start_item
, &token
);
3555 data_len
= data_len
- btrfs_token_item_offset(l
, end_item
, &token
);
3556 data_len
+= sizeof(struct btrfs_item
) * nr
;
3557 WARN_ON(data_len
< 0);
3562 * The space between the end of the leaf items and
3563 * the start of the leaf data. IOW, how much room
3564 * the leaf has left for both items and data
3566 noinline
int btrfs_leaf_free_space(struct btrfs_root
*root
,
3567 struct extent_buffer
*leaf
)
3569 int nritems
= btrfs_header_nritems(leaf
);
3571 ret
= BTRFS_LEAF_DATA_SIZE(root
) - leaf_space_used(leaf
, 0, nritems
);
3573 btrfs_crit(root
->fs_info
,
3574 "leaf free space ret %d, leaf data size %lu, used %d nritems %d",
3575 ret
, (unsigned long) BTRFS_LEAF_DATA_SIZE(root
),
3576 leaf_space_used(leaf
, 0, nritems
), nritems
);
3582 * min slot controls the lowest index we're willing to push to the
3583 * right. We'll push up to and including min_slot, but no lower
3585 static noinline
int __push_leaf_right(struct btrfs_trans_handle
*trans
,
3586 struct btrfs_root
*root
,
3587 struct btrfs_path
*path
,
3588 int data_size
, int empty
,
3589 struct extent_buffer
*right
,
3590 int free_space
, u32 left_nritems
,
3593 struct extent_buffer
*left
= path
->nodes
[0];
3594 struct extent_buffer
*upper
= path
->nodes
[1];
3595 struct btrfs_map_token token
;
3596 struct btrfs_disk_key disk_key
;
3601 struct btrfs_item
*item
;
3607 btrfs_init_map_token(&token
);
3612 nr
= max_t(u32
, 1, min_slot
);
3614 if (path
->slots
[0] >= left_nritems
)
3615 push_space
+= data_size
;
3617 slot
= path
->slots
[1];
3618 i
= left_nritems
- 1;
3620 item
= btrfs_item_nr(i
);
3622 if (!empty
&& push_items
> 0) {
3623 if (path
->slots
[0] > i
)
3625 if (path
->slots
[0] == i
) {
3626 int space
= btrfs_leaf_free_space(root
, left
);
3627 if (space
+ push_space
* 2 > free_space
)
3632 if (path
->slots
[0] == i
)
3633 push_space
+= data_size
;
3635 this_item_size
= btrfs_item_size(left
, item
);
3636 if (this_item_size
+ sizeof(*item
) + push_space
> free_space
)
3640 push_space
+= this_item_size
+ sizeof(*item
);
3646 if (push_items
== 0)
3649 WARN_ON(!empty
&& push_items
== left_nritems
);
3651 /* push left to right */
3652 right_nritems
= btrfs_header_nritems(right
);
3654 push_space
= btrfs_item_end_nr(left
, left_nritems
- push_items
);
3655 push_space
-= leaf_data_end(root
, left
);
3657 /* make room in the right data area */
3658 data_end
= leaf_data_end(root
, right
);
3659 memmove_extent_buffer(right
,
3660 btrfs_leaf_data(right
) + data_end
- push_space
,
3661 btrfs_leaf_data(right
) + data_end
,
3662 BTRFS_LEAF_DATA_SIZE(root
) - data_end
);
3664 /* copy from the left data area */
3665 copy_extent_buffer(right
, left
, btrfs_leaf_data(right
) +
3666 BTRFS_LEAF_DATA_SIZE(root
) - push_space
,
3667 btrfs_leaf_data(left
) + leaf_data_end(root
, left
),
3670 memmove_extent_buffer(right
, btrfs_item_nr_offset(push_items
),
3671 btrfs_item_nr_offset(0),
3672 right_nritems
* sizeof(struct btrfs_item
));
3674 /* copy the items from left to right */
3675 copy_extent_buffer(right
, left
, btrfs_item_nr_offset(0),
3676 btrfs_item_nr_offset(left_nritems
- push_items
),
3677 push_items
* sizeof(struct btrfs_item
));
3679 /* update the item pointers */
3680 right_nritems
+= push_items
;
3681 btrfs_set_header_nritems(right
, right_nritems
);
3682 push_space
= BTRFS_LEAF_DATA_SIZE(root
);
3683 for (i
= 0; i
< right_nritems
; i
++) {
3684 item
= btrfs_item_nr(i
);
3685 push_space
-= btrfs_token_item_size(right
, item
, &token
);
3686 btrfs_set_token_item_offset(right
, item
, push_space
, &token
);
3689 left_nritems
-= push_items
;
3690 btrfs_set_header_nritems(left
, left_nritems
);
3693 btrfs_mark_buffer_dirty(left
);
3695 clean_tree_block(trans
, root
, left
);
3697 btrfs_mark_buffer_dirty(right
);
3699 btrfs_item_key(right
, &disk_key
, 0);
3700 btrfs_set_node_key(upper
, &disk_key
, slot
+ 1);
3701 btrfs_mark_buffer_dirty(upper
);
3703 /* then fixup the leaf pointer in the path */
3704 if (path
->slots
[0] >= left_nritems
) {
3705 path
->slots
[0] -= left_nritems
;
3706 if (btrfs_header_nritems(path
->nodes
[0]) == 0)
3707 clean_tree_block(trans
, root
, path
->nodes
[0]);
3708 btrfs_tree_unlock(path
->nodes
[0]);
3709 free_extent_buffer(path
->nodes
[0]);
3710 path
->nodes
[0] = right
;
3711 path
->slots
[1] += 1;
3713 btrfs_tree_unlock(right
);
3714 free_extent_buffer(right
);
3719 btrfs_tree_unlock(right
);
3720 free_extent_buffer(right
);
3725 * push some data in the path leaf to the right, trying to free up at
3726 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3728 * returns 1 if the push failed because the other node didn't have enough
3729 * room, 0 if everything worked out and < 0 if there were major errors.
3731 * this will push starting from min_slot to the end of the leaf. It won't
3732 * push any slot lower than min_slot
3734 static int push_leaf_right(struct btrfs_trans_handle
*trans
, struct btrfs_root
3735 *root
, struct btrfs_path
*path
,
3736 int min_data_size
, int data_size
,
3737 int empty
, u32 min_slot
)
3739 struct extent_buffer
*left
= path
->nodes
[0];
3740 struct extent_buffer
*right
;
3741 struct extent_buffer
*upper
;
3747 if (!path
->nodes
[1])
3750 slot
= path
->slots
[1];
3751 upper
= path
->nodes
[1];
3752 if (slot
>= btrfs_header_nritems(upper
) - 1)
3755 btrfs_assert_tree_locked(path
->nodes
[1]);
3757 right
= read_node_slot(root
, upper
, slot
+ 1);
3761 btrfs_tree_lock(right
);
3762 btrfs_set_lock_blocking(right
);
3764 free_space
= btrfs_leaf_free_space(root
, right
);
3765 if (free_space
< data_size
)
3768 /* cow and double check */
3769 ret
= btrfs_cow_block(trans
, root
, right
, upper
,
3774 free_space
= btrfs_leaf_free_space(root
, right
);
3775 if (free_space
< data_size
)
3778 left_nritems
= btrfs_header_nritems(left
);
3779 if (left_nritems
== 0)
3782 if (path
->slots
[0] == left_nritems
&& !empty
) {
3783 /* Key greater than all keys in the leaf, right neighbor has
3784 * enough room for it and we're not emptying our leaf to delete
3785 * it, therefore use right neighbor to insert the new item and
3786 * no need to touch/dirty our left leaft. */
3787 btrfs_tree_unlock(left
);
3788 free_extent_buffer(left
);
3789 path
->nodes
[0] = right
;
3795 return __push_leaf_right(trans
, root
, path
, min_data_size
, empty
,
3796 right
, free_space
, left_nritems
, min_slot
);
3798 btrfs_tree_unlock(right
);
3799 free_extent_buffer(right
);
3804 * push some data in the path leaf to the left, trying to free up at
3805 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3807 * max_slot can put a limit on how far into the leaf we'll push items. The
3808 * item at 'max_slot' won't be touched. Use (u32)-1 to make us do all the
3811 static noinline
int __push_leaf_left(struct btrfs_trans_handle
*trans
,
3812 struct btrfs_root
*root
,
3813 struct btrfs_path
*path
, int data_size
,
3814 int empty
, struct extent_buffer
*left
,
3815 int free_space
, u32 right_nritems
,
3818 struct btrfs_disk_key disk_key
;
3819 struct extent_buffer
*right
= path
->nodes
[0];
3823 struct btrfs_item
*item
;
3824 u32 old_left_nritems
;
3828 u32 old_left_item_size
;
3829 struct btrfs_map_token token
;
3831 btrfs_init_map_token(&token
);
3834 nr
= min(right_nritems
, max_slot
);
3836 nr
= min(right_nritems
- 1, max_slot
);
3838 for (i
= 0; i
< nr
; i
++) {
3839 item
= btrfs_item_nr(i
);
3841 if (!empty
&& push_items
> 0) {
3842 if (path
->slots
[0] < i
)
3844 if (path
->slots
[0] == i
) {
3845 int space
= btrfs_leaf_free_space(root
, right
);
3846 if (space
+ push_space
* 2 > free_space
)
3851 if (path
->slots
[0] == i
)
3852 push_space
+= data_size
;
3854 this_item_size
= btrfs_item_size(right
, item
);
3855 if (this_item_size
+ sizeof(*item
) + push_space
> free_space
)
3859 push_space
+= this_item_size
+ sizeof(*item
);
3862 if (push_items
== 0) {
3866 WARN_ON(!empty
&& push_items
== btrfs_header_nritems(right
));
3868 /* push data from right to left */
3869 copy_extent_buffer(left
, right
,
3870 btrfs_item_nr_offset(btrfs_header_nritems(left
)),
3871 btrfs_item_nr_offset(0),
3872 push_items
* sizeof(struct btrfs_item
));
3874 push_space
= BTRFS_LEAF_DATA_SIZE(root
) -
3875 btrfs_item_offset_nr(right
, push_items
- 1);
3877 copy_extent_buffer(left
, right
, btrfs_leaf_data(left
) +
3878 leaf_data_end(root
, left
) - push_space
,
3879 btrfs_leaf_data(right
) +
3880 btrfs_item_offset_nr(right
, push_items
- 1),
3882 old_left_nritems
= btrfs_header_nritems(left
);
3883 BUG_ON(old_left_nritems
<= 0);
3885 old_left_item_size
= btrfs_item_offset_nr(left
, old_left_nritems
- 1);
3886 for (i
= old_left_nritems
; i
< old_left_nritems
+ push_items
; i
++) {
3889 item
= btrfs_item_nr(i
);
3891 ioff
= btrfs_token_item_offset(left
, item
, &token
);
3892 btrfs_set_token_item_offset(left
, item
,
3893 ioff
- (BTRFS_LEAF_DATA_SIZE(root
) - old_left_item_size
),
3896 btrfs_set_header_nritems(left
, old_left_nritems
+ push_items
);
3898 /* fixup right node */
3899 if (push_items
> right_nritems
)
3900 WARN(1, KERN_CRIT
"push items %d nr %u\n", push_items
,
3903 if (push_items
< right_nritems
) {
3904 push_space
= btrfs_item_offset_nr(right
, push_items
- 1) -
3905 leaf_data_end(root
, right
);
3906 memmove_extent_buffer(right
, btrfs_leaf_data(right
) +
3907 BTRFS_LEAF_DATA_SIZE(root
) - push_space
,
3908 btrfs_leaf_data(right
) +
3909 leaf_data_end(root
, right
), push_space
);
3911 memmove_extent_buffer(right
, btrfs_item_nr_offset(0),
3912 btrfs_item_nr_offset(push_items
),
3913 (btrfs_header_nritems(right
) - push_items
) *
3914 sizeof(struct btrfs_item
));
3916 right_nritems
-= push_items
;
3917 btrfs_set_header_nritems(right
, right_nritems
);
3918 push_space
= BTRFS_LEAF_DATA_SIZE(root
);
3919 for (i
= 0; i
< right_nritems
; i
++) {
3920 item
= btrfs_item_nr(i
);
3922 push_space
= push_space
- btrfs_token_item_size(right
,
3924 btrfs_set_token_item_offset(right
, item
, push_space
, &token
);
3927 btrfs_mark_buffer_dirty(left
);
3929 btrfs_mark_buffer_dirty(right
);
3931 clean_tree_block(trans
, root
, right
);
3933 btrfs_item_key(right
, &disk_key
, 0);
3934 fixup_low_keys(root
, path
, &disk_key
, 1);
3936 /* then fixup the leaf pointer in the path */
3937 if (path
->slots
[0] < push_items
) {
3938 path
->slots
[0] += old_left_nritems
;
3939 btrfs_tree_unlock(path
->nodes
[0]);
3940 free_extent_buffer(path
->nodes
[0]);
3941 path
->nodes
[0] = left
;
3942 path
->slots
[1] -= 1;
3944 btrfs_tree_unlock(left
);
3945 free_extent_buffer(left
);
3946 path
->slots
[0] -= push_items
;
3948 BUG_ON(path
->slots
[0] < 0);
3951 btrfs_tree_unlock(left
);
3952 free_extent_buffer(left
);
3957 * push some data in the path leaf to the left, trying to free up at
3958 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3960 * max_slot can put a limit on how far into the leaf we'll push items. The
3961 * item at 'max_slot' won't be touched. Use (u32)-1 to make us push all the
3964 static int push_leaf_left(struct btrfs_trans_handle
*trans
, struct btrfs_root
3965 *root
, struct btrfs_path
*path
, int min_data_size
,
3966 int data_size
, int empty
, u32 max_slot
)
3968 struct extent_buffer
*right
= path
->nodes
[0];
3969 struct extent_buffer
*left
;
3975 slot
= path
->slots
[1];
3978 if (!path
->nodes
[1])
3981 right_nritems
= btrfs_header_nritems(right
);
3982 if (right_nritems
== 0)
3985 btrfs_assert_tree_locked(path
->nodes
[1]);
3987 left
= read_node_slot(root
, path
->nodes
[1], slot
- 1);
3991 btrfs_tree_lock(left
);
3992 btrfs_set_lock_blocking(left
);
3994 free_space
= btrfs_leaf_free_space(root
, left
);
3995 if (free_space
< data_size
) {
4000 /* cow and double check */
4001 ret
= btrfs_cow_block(trans
, root
, left
,
4002 path
->nodes
[1], slot
- 1, &left
);
4004 /* we hit -ENOSPC, but it isn't fatal here */
4010 free_space
= btrfs_leaf_free_space(root
, left
);
4011 if (free_space
< data_size
) {
4016 return __push_leaf_left(trans
, root
, path
, min_data_size
,
4017 empty
, left
, free_space
, right_nritems
,
4020 btrfs_tree_unlock(left
);
4021 free_extent_buffer(left
);
4026 * split the path's leaf in two, making sure there is at least data_size
4027 * available for the resulting leaf level of the path.
4029 static noinline
void copy_for_split(struct btrfs_trans_handle
*trans
,
4030 struct btrfs_root
*root
,
4031 struct btrfs_path
*path
,
4032 struct extent_buffer
*l
,
4033 struct extent_buffer
*right
,
4034 int slot
, int mid
, int nritems
)
4039 struct btrfs_disk_key disk_key
;
4040 struct btrfs_map_token token
;
4042 btrfs_init_map_token(&token
);
4044 nritems
= nritems
- mid
;
4045 btrfs_set_header_nritems(right
, nritems
);
4046 data_copy_size
= btrfs_item_end_nr(l
, mid
) - leaf_data_end(root
, l
);
4048 copy_extent_buffer(right
, l
, btrfs_item_nr_offset(0),
4049 btrfs_item_nr_offset(mid
),
4050 nritems
* sizeof(struct btrfs_item
));
4052 copy_extent_buffer(right
, l
,
4053 btrfs_leaf_data(right
) + BTRFS_LEAF_DATA_SIZE(root
) -
4054 data_copy_size
, btrfs_leaf_data(l
) +
4055 leaf_data_end(root
, l
), data_copy_size
);
4057 rt_data_off
= BTRFS_LEAF_DATA_SIZE(root
) -
4058 btrfs_item_end_nr(l
, mid
);
4060 for (i
= 0; i
< nritems
; i
++) {
4061 struct btrfs_item
*item
= btrfs_item_nr(i
);
4064 ioff
= btrfs_token_item_offset(right
, item
, &token
);
4065 btrfs_set_token_item_offset(right
, item
,
4066 ioff
+ rt_data_off
, &token
);
4069 btrfs_set_header_nritems(l
, mid
);
4070 btrfs_item_key(right
, &disk_key
, 0);
4071 insert_ptr(trans
, root
, path
, &disk_key
, right
->start
,
4072 path
->slots
[1] + 1, 1);
4074 btrfs_mark_buffer_dirty(right
);
4075 btrfs_mark_buffer_dirty(l
);
4076 BUG_ON(path
->slots
[0] != slot
);
4079 btrfs_tree_unlock(path
->nodes
[0]);
4080 free_extent_buffer(path
->nodes
[0]);
4081 path
->nodes
[0] = right
;
4082 path
->slots
[0] -= mid
;
4083 path
->slots
[1] += 1;
4085 btrfs_tree_unlock(right
);
4086 free_extent_buffer(right
);
4089 BUG_ON(path
->slots
[0] < 0);
4093 * double splits happen when we need to insert a big item in the middle
4094 * of a leaf. A double split can leave us with 3 mostly empty leaves:
4095 * leaf: [ slots 0 - N] [ our target ] [ N + 1 - total in leaf ]
4098 * We avoid this by trying to push the items on either side of our target
4099 * into the adjacent leaves. If all goes well we can avoid the double split
4102 static noinline
int push_for_double_split(struct btrfs_trans_handle
*trans
,
4103 struct btrfs_root
*root
,
4104 struct btrfs_path
*path
,
4111 int space_needed
= data_size
;
4113 slot
= path
->slots
[0];
4114 if (slot
< btrfs_header_nritems(path
->nodes
[0]))
4115 space_needed
-= btrfs_leaf_free_space(root
, path
->nodes
[0]);
4118 * try to push all the items after our slot into the
4121 ret
= push_leaf_right(trans
, root
, path
, 1, space_needed
, 0, slot
);
4128 nritems
= btrfs_header_nritems(path
->nodes
[0]);
4130 * our goal is to get our slot at the start or end of a leaf. If
4131 * we've done so we're done
4133 if (path
->slots
[0] == 0 || path
->slots
[0] == nritems
)
4136 if (btrfs_leaf_free_space(root
, path
->nodes
[0]) >= data_size
)
4139 /* try to push all the items before our slot into the next leaf */
4140 slot
= path
->slots
[0];
4141 ret
= push_leaf_left(trans
, root
, path
, 1, space_needed
, 0, slot
);
4154 * split the path's leaf in two, making sure there is at least data_size
4155 * available for the resulting leaf level of the path.
4157 * returns 0 if all went well and < 0 on failure.
4159 static noinline
int split_leaf(struct btrfs_trans_handle
*trans
,
4160 struct btrfs_root
*root
,
4161 struct btrfs_key
*ins_key
,
4162 struct btrfs_path
*path
, int data_size
,
4165 struct btrfs_disk_key disk_key
;
4166 struct extent_buffer
*l
;
4170 struct extent_buffer
*right
;
4174 int num_doubles
= 0;
4175 int tried_avoid_double
= 0;
4178 slot
= path
->slots
[0];
4179 if (extend
&& data_size
+ btrfs_item_size_nr(l
, slot
) +
4180 sizeof(struct btrfs_item
) > BTRFS_LEAF_DATA_SIZE(root
))
4183 /* first try to make some room by pushing left and right */
4184 if (data_size
&& path
->nodes
[1]) {
4185 int space_needed
= data_size
;
4187 if (slot
< btrfs_header_nritems(l
))
4188 space_needed
-= btrfs_leaf_free_space(root
, l
);
4190 wret
= push_leaf_right(trans
, root
, path
, space_needed
,
4191 space_needed
, 0, 0);
4195 wret
= push_leaf_left(trans
, root
, path
, space_needed
,
4196 space_needed
, 0, (u32
)-1);
4202 /* did the pushes work? */
4203 if (btrfs_leaf_free_space(root
, l
) >= data_size
)
4207 if (!path
->nodes
[1]) {
4208 ret
= insert_new_root(trans
, root
, path
, 1);
4215 slot
= path
->slots
[0];
4216 nritems
= btrfs_header_nritems(l
);
4217 mid
= (nritems
+ 1) / 2;
4221 leaf_space_used(l
, mid
, nritems
- mid
) + data_size
>
4222 BTRFS_LEAF_DATA_SIZE(root
)) {
4223 if (slot
>= nritems
) {
4227 if (mid
!= nritems
&&
4228 leaf_space_used(l
, mid
, nritems
- mid
) +
4229 data_size
> BTRFS_LEAF_DATA_SIZE(root
)) {
4230 if (data_size
&& !tried_avoid_double
)
4231 goto push_for_double
;
4237 if (leaf_space_used(l
, 0, mid
) + data_size
>
4238 BTRFS_LEAF_DATA_SIZE(root
)) {
4239 if (!extend
&& data_size
&& slot
== 0) {
4241 } else if ((extend
|| !data_size
) && slot
== 0) {
4245 if (mid
!= nritems
&&
4246 leaf_space_used(l
, mid
, nritems
- mid
) +
4247 data_size
> BTRFS_LEAF_DATA_SIZE(root
)) {
4248 if (data_size
&& !tried_avoid_double
)
4249 goto push_for_double
;
4257 btrfs_cpu_key_to_disk(&disk_key
, ins_key
);
4259 btrfs_item_key(l
, &disk_key
, mid
);
4261 right
= btrfs_alloc_tree_block(trans
, root
, 0, root
->root_key
.objectid
,
4262 &disk_key
, 0, l
->start
, 0);
4264 return PTR_ERR(right
);
4266 root_add_used(root
, root
->nodesize
);
4268 memset_extent_buffer(right
, 0, 0, sizeof(struct btrfs_header
));
4269 btrfs_set_header_bytenr(right
, right
->start
);
4270 btrfs_set_header_generation(right
, trans
->transid
);
4271 btrfs_set_header_backref_rev(right
, BTRFS_MIXED_BACKREF_REV
);
4272 btrfs_set_header_owner(right
, root
->root_key
.objectid
);
4273 btrfs_set_header_level(right
, 0);
4274 write_extent_buffer(right
, root
->fs_info
->fsid
,
4275 btrfs_header_fsid(), BTRFS_FSID_SIZE
);
4277 write_extent_buffer(right
, root
->fs_info
->chunk_tree_uuid
,
4278 btrfs_header_chunk_tree_uuid(right
),
4283 btrfs_set_header_nritems(right
, 0);
4284 insert_ptr(trans
, root
, path
, &disk_key
, right
->start
,
4285 path
->slots
[1] + 1, 1);
4286 btrfs_tree_unlock(path
->nodes
[0]);
4287 free_extent_buffer(path
->nodes
[0]);
4288 path
->nodes
[0] = right
;
4290 path
->slots
[1] += 1;
4292 btrfs_set_header_nritems(right
, 0);
4293 insert_ptr(trans
, root
, path
, &disk_key
, right
->start
,
4295 btrfs_tree_unlock(path
->nodes
[0]);
4296 free_extent_buffer(path
->nodes
[0]);
4297 path
->nodes
[0] = right
;
4299 if (path
->slots
[1] == 0)
4300 fixup_low_keys(root
, path
, &disk_key
, 1);
4302 btrfs_mark_buffer_dirty(right
);
4306 copy_for_split(trans
, root
, path
, l
, right
, slot
, mid
, nritems
);
4309 BUG_ON(num_doubles
!= 0);
4317 push_for_double_split(trans
, root
, path
, data_size
);
4318 tried_avoid_double
= 1;
4319 if (btrfs_leaf_free_space(root
, path
->nodes
[0]) >= data_size
)
4324 static noinline
int setup_leaf_for_split(struct btrfs_trans_handle
*trans
,
4325 struct btrfs_root
*root
,
4326 struct btrfs_path
*path
, int ins_len
)
4328 struct btrfs_key key
;
4329 struct extent_buffer
*leaf
;
4330 struct btrfs_file_extent_item
*fi
;
4335 leaf
= path
->nodes
[0];
4336 btrfs_item_key_to_cpu(leaf
, &key
, path
->slots
[0]);
4338 BUG_ON(key
.type
!= BTRFS_EXTENT_DATA_KEY
&&
4339 key
.type
!= BTRFS_EXTENT_CSUM_KEY
);
4341 if (btrfs_leaf_free_space(root
, leaf
) >= ins_len
)
4344 item_size
= btrfs_item_size_nr(leaf
, path
->slots
[0]);
4345 if (key
.type
== BTRFS_EXTENT_DATA_KEY
) {
4346 fi
= btrfs_item_ptr(leaf
, path
->slots
[0],
4347 struct btrfs_file_extent_item
);
4348 extent_len
= btrfs_file_extent_num_bytes(leaf
, fi
);
4350 btrfs_release_path(path
);
4352 path
->keep_locks
= 1;
4353 path
->search_for_split
= 1;
4354 ret
= btrfs_search_slot(trans
, root
, &key
, path
, 0, 1);
4355 path
->search_for_split
= 0;
4362 leaf
= path
->nodes
[0];
4363 /* if our item isn't there, return now */
4364 if (item_size
!= btrfs_item_size_nr(leaf
, path
->slots
[0]))
4367 /* the leaf has changed, it now has room. return now */
4368 if (btrfs_leaf_free_space(root
, path
->nodes
[0]) >= ins_len
)
4371 if (key
.type
== BTRFS_EXTENT_DATA_KEY
) {
4372 fi
= btrfs_item_ptr(leaf
, path
->slots
[0],
4373 struct btrfs_file_extent_item
);
4374 if (extent_len
!= btrfs_file_extent_num_bytes(leaf
, fi
))
4378 btrfs_set_path_blocking(path
);
4379 ret
= split_leaf(trans
, root
, &key
, path
, ins_len
, 1);
4383 path
->keep_locks
= 0;
4384 btrfs_unlock_up_safe(path
, 1);
4387 path
->keep_locks
= 0;
4391 static noinline
int split_item(struct btrfs_trans_handle
*trans
,
4392 struct btrfs_root
*root
,
4393 struct btrfs_path
*path
,
4394 struct btrfs_key
*new_key
,
4395 unsigned long split_offset
)
4397 struct extent_buffer
*leaf
;
4398 struct btrfs_item
*item
;
4399 struct btrfs_item
*new_item
;
4405 struct btrfs_disk_key disk_key
;
4407 leaf
= path
->nodes
[0];
4408 BUG_ON(btrfs_leaf_free_space(root
, leaf
) < sizeof(struct btrfs_item
));
4410 btrfs_set_path_blocking(path
);
4412 item
= btrfs_item_nr(path
->slots
[0]);
4413 orig_offset
= btrfs_item_offset(leaf
, item
);
4414 item_size
= btrfs_item_size(leaf
, item
);
4416 buf
= kmalloc(item_size
, GFP_NOFS
);
4420 read_extent_buffer(leaf
, buf
, btrfs_item_ptr_offset(leaf
,
4421 path
->slots
[0]), item_size
);
4423 slot
= path
->slots
[0] + 1;
4424 nritems
= btrfs_header_nritems(leaf
);
4425 if (slot
!= nritems
) {
4426 /* shift the items */
4427 memmove_extent_buffer(leaf
, btrfs_item_nr_offset(slot
+ 1),
4428 btrfs_item_nr_offset(slot
),
4429 (nritems
- slot
) * sizeof(struct btrfs_item
));
4432 btrfs_cpu_key_to_disk(&disk_key
, new_key
);
4433 btrfs_set_item_key(leaf
, &disk_key
, slot
);
4435 new_item
= btrfs_item_nr(slot
);
4437 btrfs_set_item_offset(leaf
, new_item
, orig_offset
);
4438 btrfs_set_item_size(leaf
, new_item
, item_size
- split_offset
);
4440 btrfs_set_item_offset(leaf
, item
,
4441 orig_offset
+ item_size
- split_offset
);
4442 btrfs_set_item_size(leaf
, item
, split_offset
);
4444 btrfs_set_header_nritems(leaf
, nritems
+ 1);
4446 /* write the data for the start of the original item */
4447 write_extent_buffer(leaf
, buf
,
4448 btrfs_item_ptr_offset(leaf
, path
->slots
[0]),
4451 /* write the data for the new item */
4452 write_extent_buffer(leaf
, buf
+ split_offset
,
4453 btrfs_item_ptr_offset(leaf
, slot
),
4454 item_size
- split_offset
);
4455 btrfs_mark_buffer_dirty(leaf
);
4457 BUG_ON(btrfs_leaf_free_space(root
, leaf
) < 0);
4463 * This function splits a single item into two items,
4464 * giving 'new_key' to the new item and splitting the
4465 * old one at split_offset (from the start of the item).
4467 * The path may be released by this operation. After
4468 * the split, the path is pointing to the old item. The
4469 * new item is going to be in the same node as the old one.
4471 * Note, the item being split must be smaller enough to live alone on
4472 * a tree block with room for one extra struct btrfs_item
4474 * This allows us to split the item in place, keeping a lock on the
4475 * leaf the entire time.
4477 int btrfs_split_item(struct btrfs_trans_handle
*trans
,
4478 struct btrfs_root
*root
,
4479 struct btrfs_path
*path
,
4480 struct btrfs_key
*new_key
,
4481 unsigned long split_offset
)
4484 ret
= setup_leaf_for_split(trans
, root
, path
,
4485 sizeof(struct btrfs_item
));
4489 ret
= split_item(trans
, root
, path
, new_key
, split_offset
);
4494 * This function duplicate a item, giving 'new_key' to the new item.
4495 * It guarantees both items live in the same tree leaf and the new item
4496 * is contiguous with the original item.
4498 * This allows us to split file extent in place, keeping a lock on the
4499 * leaf the entire time.
4501 int btrfs_duplicate_item(struct btrfs_trans_handle
*trans
,
4502 struct btrfs_root
*root
,
4503 struct btrfs_path
*path
,
4504 struct btrfs_key
*new_key
)
4506 struct extent_buffer
*leaf
;
4510 leaf
= path
->nodes
[0];
4511 item_size
= btrfs_item_size_nr(leaf
, path
->slots
[0]);
4512 ret
= setup_leaf_for_split(trans
, root
, path
,
4513 item_size
+ sizeof(struct btrfs_item
));
4518 setup_items_for_insert(root
, path
, new_key
, &item_size
,
4519 item_size
, item_size
+
4520 sizeof(struct btrfs_item
), 1);
4521 leaf
= path
->nodes
[0];
4522 memcpy_extent_buffer(leaf
,
4523 btrfs_item_ptr_offset(leaf
, path
->slots
[0]),
4524 btrfs_item_ptr_offset(leaf
, path
->slots
[0] - 1),
4530 * make the item pointed to by the path smaller. new_size indicates
4531 * how small to make it, and from_end tells us if we just chop bytes
4532 * off the end of the item or if we shift the item to chop bytes off
4535 void btrfs_truncate_item(struct btrfs_root
*root
, struct btrfs_path
*path
,
4536 u32 new_size
, int from_end
)
4539 struct extent_buffer
*leaf
;
4540 struct btrfs_item
*item
;
4542 unsigned int data_end
;
4543 unsigned int old_data_start
;
4544 unsigned int old_size
;
4545 unsigned int size_diff
;
4547 struct btrfs_map_token token
;
4549 btrfs_init_map_token(&token
);
4551 leaf
= path
->nodes
[0];
4552 slot
= path
->slots
[0];
4554 old_size
= btrfs_item_size_nr(leaf
, slot
);
4555 if (old_size
== new_size
)
4558 nritems
= btrfs_header_nritems(leaf
);
4559 data_end
= leaf_data_end(root
, leaf
);
4561 old_data_start
= btrfs_item_offset_nr(leaf
, slot
);
4563 size_diff
= old_size
- new_size
;
4566 BUG_ON(slot
>= nritems
);
4569 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4571 /* first correct the data pointers */
4572 for (i
= slot
; i
< nritems
; i
++) {
4574 item
= btrfs_item_nr(i
);
4576 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4577 btrfs_set_token_item_offset(leaf
, item
,
4578 ioff
+ size_diff
, &token
);
4581 /* shift the data */
4583 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4584 data_end
+ size_diff
, btrfs_leaf_data(leaf
) +
4585 data_end
, old_data_start
+ new_size
- data_end
);
4587 struct btrfs_disk_key disk_key
;
4590 btrfs_item_key(leaf
, &disk_key
, slot
);
4592 if (btrfs_disk_key_type(&disk_key
) == BTRFS_EXTENT_DATA_KEY
) {
4594 struct btrfs_file_extent_item
*fi
;
4596 fi
= btrfs_item_ptr(leaf
, slot
,
4597 struct btrfs_file_extent_item
);
4598 fi
= (struct btrfs_file_extent_item
*)(
4599 (unsigned long)fi
- size_diff
);
4601 if (btrfs_file_extent_type(leaf
, fi
) ==
4602 BTRFS_FILE_EXTENT_INLINE
) {
4603 ptr
= btrfs_item_ptr_offset(leaf
, slot
);
4604 memmove_extent_buffer(leaf
, ptr
,
4606 BTRFS_FILE_EXTENT_INLINE_DATA_START
);
4610 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4611 data_end
+ size_diff
, btrfs_leaf_data(leaf
) +
4612 data_end
, old_data_start
- data_end
);
4614 offset
= btrfs_disk_key_offset(&disk_key
);
4615 btrfs_set_disk_key_offset(&disk_key
, offset
+ size_diff
);
4616 btrfs_set_item_key(leaf
, &disk_key
, slot
);
4618 fixup_low_keys(root
, path
, &disk_key
, 1);
4621 item
= btrfs_item_nr(slot
);
4622 btrfs_set_item_size(leaf
, item
, new_size
);
4623 btrfs_mark_buffer_dirty(leaf
);
4625 if (btrfs_leaf_free_space(root
, leaf
) < 0) {
4626 btrfs_print_leaf(root
, leaf
);
4632 * make the item pointed to by the path bigger, data_size is the added size.
4634 void btrfs_extend_item(struct btrfs_root
*root
, struct btrfs_path
*path
,
4638 struct extent_buffer
*leaf
;
4639 struct btrfs_item
*item
;
4641 unsigned int data_end
;
4642 unsigned int old_data
;
4643 unsigned int old_size
;
4645 struct btrfs_map_token token
;
4647 btrfs_init_map_token(&token
);
4649 leaf
= path
->nodes
[0];
4651 nritems
= btrfs_header_nritems(leaf
);
4652 data_end
= leaf_data_end(root
, leaf
);
4654 if (btrfs_leaf_free_space(root
, leaf
) < data_size
) {
4655 btrfs_print_leaf(root
, leaf
);
4658 slot
= path
->slots
[0];
4659 old_data
= btrfs_item_end_nr(leaf
, slot
);
4662 if (slot
>= nritems
) {
4663 btrfs_print_leaf(root
, leaf
);
4664 btrfs_crit(root
->fs_info
, "slot %d too large, nritems %d",
4670 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4672 /* first correct the data pointers */
4673 for (i
= slot
; i
< nritems
; i
++) {
4675 item
= btrfs_item_nr(i
);
4677 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4678 btrfs_set_token_item_offset(leaf
, item
,
4679 ioff
- data_size
, &token
);
4682 /* shift the data */
4683 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4684 data_end
- data_size
, btrfs_leaf_data(leaf
) +
4685 data_end
, old_data
- data_end
);
4687 data_end
= old_data
;
4688 old_size
= btrfs_item_size_nr(leaf
, slot
);
4689 item
= btrfs_item_nr(slot
);
4690 btrfs_set_item_size(leaf
, item
, old_size
+ data_size
);
4691 btrfs_mark_buffer_dirty(leaf
);
4693 if (btrfs_leaf_free_space(root
, leaf
) < 0) {
4694 btrfs_print_leaf(root
, leaf
);
4700 * this is a helper for btrfs_insert_empty_items, the main goal here is
4701 * to save stack depth by doing the bulk of the work in a function
4702 * that doesn't call btrfs_search_slot
4704 void setup_items_for_insert(struct btrfs_root
*root
, struct btrfs_path
*path
,
4705 struct btrfs_key
*cpu_key
, u32
*data_size
,
4706 u32 total_data
, u32 total_size
, int nr
)
4708 struct btrfs_item
*item
;
4711 unsigned int data_end
;
4712 struct btrfs_disk_key disk_key
;
4713 struct extent_buffer
*leaf
;
4715 struct btrfs_map_token token
;
4717 if (path
->slots
[0] == 0) {
4718 btrfs_cpu_key_to_disk(&disk_key
, cpu_key
);
4719 fixup_low_keys(root
, path
, &disk_key
, 1);
4721 btrfs_unlock_up_safe(path
, 1);
4723 btrfs_init_map_token(&token
);
4725 leaf
= path
->nodes
[0];
4726 slot
= path
->slots
[0];
4728 nritems
= btrfs_header_nritems(leaf
);
4729 data_end
= leaf_data_end(root
, leaf
);
4731 if (btrfs_leaf_free_space(root
, leaf
) < total_size
) {
4732 btrfs_print_leaf(root
, leaf
);
4733 btrfs_crit(root
->fs_info
, "not enough freespace need %u have %d",
4734 total_size
, btrfs_leaf_free_space(root
, leaf
));
4738 if (slot
!= nritems
) {
4739 unsigned int old_data
= btrfs_item_end_nr(leaf
, slot
);
4741 if (old_data
< data_end
) {
4742 btrfs_print_leaf(root
, leaf
);
4743 btrfs_crit(root
->fs_info
, "slot %d old_data %d data_end %d",
4744 slot
, old_data
, data_end
);
4748 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4750 /* first correct the data pointers */
4751 for (i
= slot
; i
< nritems
; i
++) {
4754 item
= btrfs_item_nr( i
);
4755 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4756 btrfs_set_token_item_offset(leaf
, item
,
4757 ioff
- total_data
, &token
);
4759 /* shift the items */
4760 memmove_extent_buffer(leaf
, btrfs_item_nr_offset(slot
+ nr
),
4761 btrfs_item_nr_offset(slot
),
4762 (nritems
- slot
) * sizeof(struct btrfs_item
));
4764 /* shift the data */
4765 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4766 data_end
- total_data
, btrfs_leaf_data(leaf
) +
4767 data_end
, old_data
- data_end
);
4768 data_end
= old_data
;
4771 /* setup the item for the new data */
4772 for (i
= 0; i
< nr
; i
++) {
4773 btrfs_cpu_key_to_disk(&disk_key
, cpu_key
+ i
);
4774 btrfs_set_item_key(leaf
, &disk_key
, slot
+ i
);
4775 item
= btrfs_item_nr(slot
+ i
);
4776 btrfs_set_token_item_offset(leaf
, item
,
4777 data_end
- data_size
[i
], &token
);
4778 data_end
-= data_size
[i
];
4779 btrfs_set_token_item_size(leaf
, item
, data_size
[i
], &token
);
4782 btrfs_set_header_nritems(leaf
, nritems
+ nr
);
4783 btrfs_mark_buffer_dirty(leaf
);
4785 if (btrfs_leaf_free_space(root
, leaf
) < 0) {
4786 btrfs_print_leaf(root
, leaf
);
4792 * Given a key and some data, insert items into the tree.
4793 * This does all the path init required, making room in the tree if needed.
4795 int btrfs_insert_empty_items(struct btrfs_trans_handle
*trans
,
4796 struct btrfs_root
*root
,
4797 struct btrfs_path
*path
,
4798 struct btrfs_key
*cpu_key
, u32
*data_size
,
4807 for (i
= 0; i
< nr
; i
++)
4808 total_data
+= data_size
[i
];
4810 total_size
= total_data
+ (nr
* sizeof(struct btrfs_item
));
4811 ret
= btrfs_search_slot(trans
, root
, cpu_key
, path
, total_size
, 1);
4817 slot
= path
->slots
[0];
4820 setup_items_for_insert(root
, path
, cpu_key
, data_size
,
4821 total_data
, total_size
, nr
);
4826 * Given a key and some data, insert an item into the tree.
4827 * This does all the path init required, making room in the tree if needed.
4829 int btrfs_insert_item(struct btrfs_trans_handle
*trans
, struct btrfs_root
4830 *root
, struct btrfs_key
*cpu_key
, void *data
, u32
4834 struct btrfs_path
*path
;
4835 struct extent_buffer
*leaf
;
4838 path
= btrfs_alloc_path();
4841 ret
= btrfs_insert_empty_item(trans
, root
, path
, cpu_key
, data_size
);
4843 leaf
= path
->nodes
[0];
4844 ptr
= btrfs_item_ptr_offset(leaf
, path
->slots
[0]);
4845 write_extent_buffer(leaf
, data
, ptr
, data_size
);
4846 btrfs_mark_buffer_dirty(leaf
);
4848 btrfs_free_path(path
);
4853 * delete the pointer from a given node.
4855 * the tree should have been previously balanced so the deletion does not
4858 static void del_ptr(struct btrfs_root
*root
, struct btrfs_path
*path
,
4859 int level
, int slot
)
4861 struct extent_buffer
*parent
= path
->nodes
[level
];
4865 nritems
= btrfs_header_nritems(parent
);
4866 if (slot
!= nritems
- 1) {
4868 tree_mod_log_eb_move(root
->fs_info
, parent
, slot
,
4869 slot
+ 1, nritems
- slot
- 1);
4870 memmove_extent_buffer(parent
,
4871 btrfs_node_key_ptr_offset(slot
),
4872 btrfs_node_key_ptr_offset(slot
+ 1),
4873 sizeof(struct btrfs_key_ptr
) *
4874 (nritems
- slot
- 1));
4876 ret
= tree_mod_log_insert_key(root
->fs_info
, parent
, slot
,
4877 MOD_LOG_KEY_REMOVE
, GFP_NOFS
);
4882 btrfs_set_header_nritems(parent
, nritems
);
4883 if (nritems
== 0 && parent
== root
->node
) {
4884 BUG_ON(btrfs_header_level(root
->node
) != 1);
4885 /* just turn the root into a leaf and break */
4886 btrfs_set_header_level(root
->node
, 0);
4887 } else if (slot
== 0) {
4888 struct btrfs_disk_key disk_key
;
4890 btrfs_node_key(parent
, &disk_key
, 0);
4891 fixup_low_keys(root
, path
, &disk_key
, level
+ 1);
4893 btrfs_mark_buffer_dirty(parent
);
4897 * a helper function to delete the leaf pointed to by path->slots[1] and
4900 * This deletes the pointer in path->nodes[1] and frees the leaf
4901 * block extent. zero is returned if it all worked out, < 0 otherwise.
4903 * The path must have already been setup for deleting the leaf, including
4904 * all the proper balancing. path->nodes[1] must be locked.
4906 static noinline
void btrfs_del_leaf(struct btrfs_trans_handle
*trans
,
4907 struct btrfs_root
*root
,
4908 struct btrfs_path
*path
,
4909 struct extent_buffer
*leaf
)
4911 WARN_ON(btrfs_header_generation(leaf
) != trans
->transid
);
4912 del_ptr(root
, path
, 1, path
->slots
[1]);
4915 * btrfs_free_extent is expensive, we want to make sure we
4916 * aren't holding any locks when we call it
4918 btrfs_unlock_up_safe(path
, 0);
4920 root_sub_used(root
, leaf
->len
);
4922 extent_buffer_get(leaf
);
4923 btrfs_free_tree_block(trans
, root
, leaf
, 0, 1);
4924 free_extent_buffer_stale(leaf
);
4927 * delete the item at the leaf level in path. If that empties
4928 * the leaf, remove it from the tree
4930 int btrfs_del_items(struct btrfs_trans_handle
*trans
, struct btrfs_root
*root
,
4931 struct btrfs_path
*path
, int slot
, int nr
)
4933 struct extent_buffer
*leaf
;
4934 struct btrfs_item
*item
;
4941 struct btrfs_map_token token
;
4943 btrfs_init_map_token(&token
);
4945 leaf
= path
->nodes
[0];
4946 last_off
= btrfs_item_offset_nr(leaf
, slot
+ nr
- 1);
4948 for (i
= 0; i
< nr
; i
++)
4949 dsize
+= btrfs_item_size_nr(leaf
, slot
+ i
);
4951 nritems
= btrfs_header_nritems(leaf
);
4953 if (slot
+ nr
!= nritems
) {
4954 int data_end
= leaf_data_end(root
, leaf
);
4956 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4958 btrfs_leaf_data(leaf
) + data_end
,
4959 last_off
- data_end
);
4961 for (i
= slot
+ nr
; i
< nritems
; i
++) {
4964 item
= btrfs_item_nr(i
);
4965 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4966 btrfs_set_token_item_offset(leaf
, item
,
4967 ioff
+ dsize
, &token
);
4970 memmove_extent_buffer(leaf
, btrfs_item_nr_offset(slot
),
4971 btrfs_item_nr_offset(slot
+ nr
),
4972 sizeof(struct btrfs_item
) *
4973 (nritems
- slot
- nr
));
4975 btrfs_set_header_nritems(leaf
, nritems
- nr
);
4978 /* delete the leaf if we've emptied it */
4980 if (leaf
== root
->node
) {
4981 btrfs_set_header_level(leaf
, 0);
4983 btrfs_set_path_blocking(path
);
4984 clean_tree_block(trans
, root
, leaf
);
4985 btrfs_del_leaf(trans
, root
, path
, leaf
);
4988 int used
= leaf_space_used(leaf
, 0, nritems
);
4990 struct btrfs_disk_key disk_key
;
4992 btrfs_item_key(leaf
, &disk_key
, 0);
4993 fixup_low_keys(root
, path
, &disk_key
, 1);
4996 /* delete the leaf if it is mostly empty */
4997 if (used
< BTRFS_LEAF_DATA_SIZE(root
) / 3) {
4998 /* push_leaf_left fixes the path.
4999 * make sure the path still points to our leaf
5000 * for possible call to del_ptr below
5002 slot
= path
->slots
[1];
5003 extent_buffer_get(leaf
);
5005 btrfs_set_path_blocking(path
);
5006 wret
= push_leaf_left(trans
, root
, path
, 1, 1,
5008 if (wret
< 0 && wret
!= -ENOSPC
)
5011 if (path
->nodes
[0] == leaf
&&
5012 btrfs_header_nritems(leaf
)) {
5013 wret
= push_leaf_right(trans
, root
, path
, 1,
5015 if (wret
< 0 && wret
!= -ENOSPC
)
5019 if (btrfs_header_nritems(leaf
) == 0) {
5020 path
->slots
[1] = slot
;
5021 btrfs_del_leaf(trans
, root
, path
, leaf
);
5022 free_extent_buffer(leaf
);
5025 /* if we're still in the path, make sure
5026 * we're dirty. Otherwise, one of the
5027 * push_leaf functions must have already
5028 * dirtied this buffer
5030 if (path
->nodes
[0] == leaf
)
5031 btrfs_mark_buffer_dirty(leaf
);
5032 free_extent_buffer(leaf
);
5035 btrfs_mark_buffer_dirty(leaf
);
5042 * search the tree again to find a leaf with lesser keys
5043 * returns 0 if it found something or 1 if there are no lesser leaves.
5044 * returns < 0 on io errors.
5046 * This may release the path, and so you may lose any locks held at the
5049 int btrfs_prev_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
)
5051 struct btrfs_key key
;
5052 struct btrfs_disk_key found_key
;
5055 btrfs_item_key_to_cpu(path
->nodes
[0], &key
, 0);
5057 if (key
.offset
> 0) {
5059 } else if (key
.type
> 0) {
5061 key
.offset
= (u64
)-1;
5062 } else if (key
.objectid
> 0) {
5065 key
.offset
= (u64
)-1;
5070 btrfs_release_path(path
);
5071 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
5074 btrfs_item_key(path
->nodes
[0], &found_key
, 0);
5075 ret
= comp_keys(&found_key
, &key
);
5077 * We might have had an item with the previous key in the tree right
5078 * before we released our path. And after we released our path, that
5079 * item might have been pushed to the first slot (0) of the leaf we
5080 * were holding due to a tree balance. Alternatively, an item with the
5081 * previous key can exist as the only element of a leaf (big fat item).
5082 * Therefore account for these 2 cases, so that our callers (like
5083 * btrfs_previous_item) don't miss an existing item with a key matching
5084 * the previous key we computed above.
5092 * A helper function to walk down the tree starting at min_key, and looking
5093 * for nodes or leaves that are have a minimum transaction id.
5094 * This is used by the btree defrag code, and tree logging
5096 * This does not cow, but it does stuff the starting key it finds back
5097 * into min_key, so you can call btrfs_search_slot with cow=1 on the
5098 * key and get a writable path.
5100 * This does lock as it descends, and path->keep_locks should be set
5101 * to 1 by the caller.
5103 * This honors path->lowest_level to prevent descent past a given level
5106 * min_trans indicates the oldest transaction that you are interested
5107 * in walking through. Any nodes or leaves older than min_trans are
5108 * skipped over (without reading them).
5110 * returns zero if something useful was found, < 0 on error and 1 if there
5111 * was nothing in the tree that matched the search criteria.
5113 int btrfs_search_forward(struct btrfs_root
*root
, struct btrfs_key
*min_key
,
5114 struct btrfs_path
*path
,
5117 struct extent_buffer
*cur
;
5118 struct btrfs_key found_key
;
5124 int keep_locks
= path
->keep_locks
;
5126 path
->keep_locks
= 1;
5128 cur
= btrfs_read_lock_root_node(root
);
5129 level
= btrfs_header_level(cur
);
5130 WARN_ON(path
->nodes
[level
]);
5131 path
->nodes
[level
] = cur
;
5132 path
->locks
[level
] = BTRFS_READ_LOCK
;
5134 if (btrfs_header_generation(cur
) < min_trans
) {
5139 nritems
= btrfs_header_nritems(cur
);
5140 level
= btrfs_header_level(cur
);
5141 sret
= bin_search(cur
, min_key
, level
, &slot
);
5143 /* at the lowest level, we're done, setup the path and exit */
5144 if (level
== path
->lowest_level
) {
5145 if (slot
>= nritems
)
5148 path
->slots
[level
] = slot
;
5149 btrfs_item_key_to_cpu(cur
, &found_key
, slot
);
5152 if (sret
&& slot
> 0)
5155 * check this node pointer against the min_trans parameters.
5156 * If it is too old, old, skip to the next one.
5158 while (slot
< nritems
) {
5161 gen
= btrfs_node_ptr_generation(cur
, slot
);
5162 if (gen
< min_trans
) {
5170 * we didn't find a candidate key in this node, walk forward
5171 * and find another one
5173 if (slot
>= nritems
) {
5174 path
->slots
[level
] = slot
;
5175 btrfs_set_path_blocking(path
);
5176 sret
= btrfs_find_next_key(root
, path
, min_key
, level
,
5179 btrfs_release_path(path
);
5185 /* save our key for returning back */
5186 btrfs_node_key_to_cpu(cur
, &found_key
, slot
);
5187 path
->slots
[level
] = slot
;
5188 if (level
== path
->lowest_level
) {
5192 btrfs_set_path_blocking(path
);
5193 cur
= read_node_slot(root
, cur
, slot
);
5194 BUG_ON(!cur
); /* -ENOMEM */
5196 btrfs_tree_read_lock(cur
);
5198 path
->locks
[level
- 1] = BTRFS_READ_LOCK
;
5199 path
->nodes
[level
- 1] = cur
;
5200 unlock_up(path
, level
, 1, 0, NULL
);
5201 btrfs_clear_path_blocking(path
, NULL
, 0);
5204 path
->keep_locks
= keep_locks
;
5206 btrfs_unlock_up_safe(path
, path
->lowest_level
+ 1);
5207 btrfs_set_path_blocking(path
);
5208 memcpy(min_key
, &found_key
, sizeof(found_key
));
5213 static void tree_move_down(struct btrfs_root
*root
,
5214 struct btrfs_path
*path
,
5215 int *level
, int root_level
)
5217 BUG_ON(*level
== 0);
5218 path
->nodes
[*level
- 1] = read_node_slot(root
, path
->nodes
[*level
],
5219 path
->slots
[*level
]);
5220 path
->slots
[*level
- 1] = 0;
5224 static int tree_move_next_or_upnext(struct btrfs_root
*root
,
5225 struct btrfs_path
*path
,
5226 int *level
, int root_level
)
5230 nritems
= btrfs_header_nritems(path
->nodes
[*level
]);
5232 path
->slots
[*level
]++;
5234 while (path
->slots
[*level
] >= nritems
) {
5235 if (*level
== root_level
)
5239 path
->slots
[*level
] = 0;
5240 free_extent_buffer(path
->nodes
[*level
]);
5241 path
->nodes
[*level
] = NULL
;
5243 path
->slots
[*level
]++;
5245 nritems
= btrfs_header_nritems(path
->nodes
[*level
]);
5252 * Returns 1 if it had to move up and next. 0 is returned if it moved only next
5255 static int tree_advance(struct btrfs_root
*root
,
5256 struct btrfs_path
*path
,
5257 int *level
, int root_level
,
5259 struct btrfs_key
*key
)
5263 if (*level
== 0 || !allow_down
) {
5264 ret
= tree_move_next_or_upnext(root
, path
, level
, root_level
);
5266 tree_move_down(root
, path
, level
, root_level
);
5271 btrfs_item_key_to_cpu(path
->nodes
[*level
], key
,
5272 path
->slots
[*level
]);
5274 btrfs_node_key_to_cpu(path
->nodes
[*level
], key
,
5275 path
->slots
[*level
]);
5280 static int tree_compare_item(struct btrfs_root
*left_root
,
5281 struct btrfs_path
*left_path
,
5282 struct btrfs_path
*right_path
,
5287 unsigned long off1
, off2
;
5289 len1
= btrfs_item_size_nr(left_path
->nodes
[0], left_path
->slots
[0]);
5290 len2
= btrfs_item_size_nr(right_path
->nodes
[0], right_path
->slots
[0]);
5294 off1
= btrfs_item_ptr_offset(left_path
->nodes
[0], left_path
->slots
[0]);
5295 off2
= btrfs_item_ptr_offset(right_path
->nodes
[0],
5296 right_path
->slots
[0]);
5298 read_extent_buffer(left_path
->nodes
[0], tmp_buf
, off1
, len1
);
5300 cmp
= memcmp_extent_buffer(right_path
->nodes
[0], tmp_buf
, off2
, len1
);
5307 #define ADVANCE_ONLY_NEXT -1
5310 * This function compares two trees and calls the provided callback for
5311 * every changed/new/deleted item it finds.
5312 * If shared tree blocks are encountered, whole subtrees are skipped, making
5313 * the compare pretty fast on snapshotted subvolumes.
5315 * This currently works on commit roots only. As commit roots are read only,
5316 * we don't do any locking. The commit roots are protected with transactions.
5317 * Transactions are ended and rejoined when a commit is tried in between.
5319 * This function checks for modifications done to the trees while comparing.
5320 * If it detects a change, it aborts immediately.
5322 int btrfs_compare_trees(struct btrfs_root
*left_root
,
5323 struct btrfs_root
*right_root
,
5324 btrfs_changed_cb_t changed_cb
, void *ctx
)
5328 struct btrfs_path
*left_path
= NULL
;
5329 struct btrfs_path
*right_path
= NULL
;
5330 struct btrfs_key left_key
;
5331 struct btrfs_key right_key
;
5332 char *tmp_buf
= NULL
;
5333 int left_root_level
;
5334 int right_root_level
;
5337 int left_end_reached
;
5338 int right_end_reached
;
5346 left_path
= btrfs_alloc_path();
5351 right_path
= btrfs_alloc_path();
5357 tmp_buf
= kmalloc(left_root
->nodesize
, GFP_NOFS
);
5363 left_path
->search_commit_root
= 1;
5364 left_path
->skip_locking
= 1;
5365 right_path
->search_commit_root
= 1;
5366 right_path
->skip_locking
= 1;
5369 * Strategy: Go to the first items of both trees. Then do
5371 * If both trees are at level 0
5372 * Compare keys of current items
5373 * If left < right treat left item as new, advance left tree
5375 * If left > right treat right item as deleted, advance right tree
5377 * If left == right do deep compare of items, treat as changed if
5378 * needed, advance both trees and repeat
5379 * If both trees are at the same level but not at level 0
5380 * Compare keys of current nodes/leafs
5381 * If left < right advance left tree and repeat
5382 * If left > right advance right tree and repeat
5383 * If left == right compare blockptrs of the next nodes/leafs
5384 * If they match advance both trees but stay at the same level
5386 * If they don't match advance both trees while allowing to go
5388 * If tree levels are different
5389 * Advance the tree that needs it and repeat
5391 * Advancing a tree means:
5392 * If we are at level 0, try to go to the next slot. If that's not
5393 * possible, go one level up and repeat. Stop when we found a level
5394 * where we could go to the next slot. We may at this point be on a
5397 * If we are not at level 0 and not on shared tree blocks, go one
5400 * If we are not at level 0 and on shared tree blocks, go one slot to
5401 * the right if possible or go up and right.
5404 down_read(&left_root
->fs_info
->commit_root_sem
);
5405 left_level
= btrfs_header_level(left_root
->commit_root
);
5406 left_root_level
= left_level
;
5407 left_path
->nodes
[left_level
] = left_root
->commit_root
;
5408 extent_buffer_get(left_path
->nodes
[left_level
]);
5410 right_level
= btrfs_header_level(right_root
->commit_root
);
5411 right_root_level
= right_level
;
5412 right_path
->nodes
[right_level
] = right_root
->commit_root
;
5413 extent_buffer_get(right_path
->nodes
[right_level
]);
5414 up_read(&left_root
->fs_info
->commit_root_sem
);
5416 if (left_level
== 0)
5417 btrfs_item_key_to_cpu(left_path
->nodes
[left_level
],
5418 &left_key
, left_path
->slots
[left_level
]);
5420 btrfs_node_key_to_cpu(left_path
->nodes
[left_level
],
5421 &left_key
, left_path
->slots
[left_level
]);
5422 if (right_level
== 0)
5423 btrfs_item_key_to_cpu(right_path
->nodes
[right_level
],
5424 &right_key
, right_path
->slots
[right_level
]);
5426 btrfs_node_key_to_cpu(right_path
->nodes
[right_level
],
5427 &right_key
, right_path
->slots
[right_level
]);
5429 left_end_reached
= right_end_reached
= 0;
5430 advance_left
= advance_right
= 0;
5433 if (advance_left
&& !left_end_reached
) {
5434 ret
= tree_advance(left_root
, left_path
, &left_level
,
5436 advance_left
!= ADVANCE_ONLY_NEXT
,
5439 left_end_reached
= ADVANCE
;
5442 if (advance_right
&& !right_end_reached
) {
5443 ret
= tree_advance(right_root
, right_path
, &right_level
,
5445 advance_right
!= ADVANCE_ONLY_NEXT
,
5448 right_end_reached
= ADVANCE
;
5452 if (left_end_reached
&& right_end_reached
) {
5455 } else if (left_end_reached
) {
5456 if (right_level
== 0) {
5457 ret
= changed_cb(left_root
, right_root
,
5458 left_path
, right_path
,
5460 BTRFS_COMPARE_TREE_DELETED
,
5465 advance_right
= ADVANCE
;
5467 } else if (right_end_reached
) {
5468 if (left_level
== 0) {
5469 ret
= changed_cb(left_root
, right_root
,
5470 left_path
, right_path
,
5472 BTRFS_COMPARE_TREE_NEW
,
5477 advance_left
= ADVANCE
;
5481 if (left_level
== 0 && right_level
== 0) {
5482 cmp
= btrfs_comp_cpu_keys(&left_key
, &right_key
);
5484 ret
= changed_cb(left_root
, right_root
,
5485 left_path
, right_path
,
5487 BTRFS_COMPARE_TREE_NEW
,
5491 advance_left
= ADVANCE
;
5492 } else if (cmp
> 0) {
5493 ret
= changed_cb(left_root
, right_root
,
5494 left_path
, right_path
,
5496 BTRFS_COMPARE_TREE_DELETED
,
5500 advance_right
= ADVANCE
;
5502 enum btrfs_compare_tree_result result
;
5504 WARN_ON(!extent_buffer_uptodate(left_path
->nodes
[0]));
5505 ret
= tree_compare_item(left_root
, left_path
,
5506 right_path
, tmp_buf
);
5508 result
= BTRFS_COMPARE_TREE_CHANGED
;
5510 result
= BTRFS_COMPARE_TREE_SAME
;
5511 ret
= changed_cb(left_root
, right_root
,
5512 left_path
, right_path
,
5513 &left_key
, result
, ctx
);
5516 advance_left
= ADVANCE
;
5517 advance_right
= ADVANCE
;
5519 } else if (left_level
== right_level
) {
5520 cmp
= btrfs_comp_cpu_keys(&left_key
, &right_key
);
5522 advance_left
= ADVANCE
;
5523 } else if (cmp
> 0) {
5524 advance_right
= ADVANCE
;
5526 left_blockptr
= btrfs_node_blockptr(
5527 left_path
->nodes
[left_level
],
5528 left_path
->slots
[left_level
]);
5529 right_blockptr
= btrfs_node_blockptr(
5530 right_path
->nodes
[right_level
],
5531 right_path
->slots
[right_level
]);
5532 left_gen
= btrfs_node_ptr_generation(
5533 left_path
->nodes
[left_level
],
5534 left_path
->slots
[left_level
]);
5535 right_gen
= btrfs_node_ptr_generation(
5536 right_path
->nodes
[right_level
],
5537 right_path
->slots
[right_level
]);
5538 if (left_blockptr
== right_blockptr
&&
5539 left_gen
== right_gen
) {
5541 * As we're on a shared block, don't
5542 * allow to go deeper.
5544 advance_left
= ADVANCE_ONLY_NEXT
;
5545 advance_right
= ADVANCE_ONLY_NEXT
;
5547 advance_left
= ADVANCE
;
5548 advance_right
= ADVANCE
;
5551 } else if (left_level
< right_level
) {
5552 advance_right
= ADVANCE
;
5554 advance_left
= ADVANCE
;
5559 btrfs_free_path(left_path
);
5560 btrfs_free_path(right_path
);
5566 * this is similar to btrfs_next_leaf, but does not try to preserve
5567 * and fixup the path. It looks for and returns the next key in the
5568 * tree based on the current path and the min_trans parameters.
5570 * 0 is returned if another key is found, < 0 if there are any errors
5571 * and 1 is returned if there are no higher keys in the tree
5573 * path->keep_locks should be set to 1 on the search made before
5574 * calling this function.
5576 int btrfs_find_next_key(struct btrfs_root
*root
, struct btrfs_path
*path
,
5577 struct btrfs_key
*key
, int level
, u64 min_trans
)
5580 struct extent_buffer
*c
;
5582 WARN_ON(!path
->keep_locks
);
5583 while (level
< BTRFS_MAX_LEVEL
) {
5584 if (!path
->nodes
[level
])
5587 slot
= path
->slots
[level
] + 1;
5588 c
= path
->nodes
[level
];
5590 if (slot
>= btrfs_header_nritems(c
)) {
5593 struct btrfs_key cur_key
;
5594 if (level
+ 1 >= BTRFS_MAX_LEVEL
||
5595 !path
->nodes
[level
+ 1])
5598 if (path
->locks
[level
+ 1]) {
5603 slot
= btrfs_header_nritems(c
) - 1;
5605 btrfs_item_key_to_cpu(c
, &cur_key
, slot
);
5607 btrfs_node_key_to_cpu(c
, &cur_key
, slot
);
5609 orig_lowest
= path
->lowest_level
;
5610 btrfs_release_path(path
);
5611 path
->lowest_level
= level
;
5612 ret
= btrfs_search_slot(NULL
, root
, &cur_key
, path
,
5614 path
->lowest_level
= orig_lowest
;
5618 c
= path
->nodes
[level
];
5619 slot
= path
->slots
[level
];
5626 btrfs_item_key_to_cpu(c
, key
, slot
);
5628 u64 gen
= btrfs_node_ptr_generation(c
, slot
);
5630 if (gen
< min_trans
) {
5634 btrfs_node_key_to_cpu(c
, key
, slot
);
5642 * search the tree again to find a leaf with greater keys
5643 * returns 0 if it found something or 1 if there are no greater leaves.
5644 * returns < 0 on io errors.
5646 int btrfs_next_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
)
5648 return btrfs_next_old_leaf(root
, path
, 0);
5651 int btrfs_next_old_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
,
5656 struct extent_buffer
*c
;
5657 struct extent_buffer
*next
;
5658 struct btrfs_key key
;
5661 int old_spinning
= path
->leave_spinning
;
5662 int next_rw_lock
= 0;
5664 nritems
= btrfs_header_nritems(path
->nodes
[0]);
5668 btrfs_item_key_to_cpu(path
->nodes
[0], &key
, nritems
- 1);
5673 btrfs_release_path(path
);
5675 path
->keep_locks
= 1;
5676 path
->leave_spinning
= 1;
5679 ret
= btrfs_search_old_slot(root
, &key
, path
, time_seq
);
5681 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
5682 path
->keep_locks
= 0;
5687 nritems
= btrfs_header_nritems(path
->nodes
[0]);
5689 * by releasing the path above we dropped all our locks. A balance
5690 * could have added more items next to the key that used to be
5691 * at the very end of the block. So, check again here and
5692 * advance the path if there are now more items available.
5694 if (nritems
> 0 && path
->slots
[0] < nritems
- 1) {
5701 * So the above check misses one case:
5702 * - after releasing the path above, someone has removed the item that
5703 * used to be at the very end of the block, and balance between leafs
5704 * gets another one with bigger key.offset to replace it.
5706 * This one should be returned as well, or we can get leaf corruption
5707 * later(esp. in __btrfs_drop_extents()).
5709 * And a bit more explanation about this check,
5710 * with ret > 0, the key isn't found, the path points to the slot
5711 * where it should be inserted, so the path->slots[0] item must be the
5714 if (nritems
> 0 && ret
> 0 && path
->slots
[0] == nritems
- 1) {
5719 while (level
< BTRFS_MAX_LEVEL
) {
5720 if (!path
->nodes
[level
]) {
5725 slot
= path
->slots
[level
] + 1;
5726 c
= path
->nodes
[level
];
5727 if (slot
>= btrfs_header_nritems(c
)) {
5729 if (level
== BTRFS_MAX_LEVEL
) {
5737 btrfs_tree_unlock_rw(next
, next_rw_lock
);
5738 free_extent_buffer(next
);
5742 next_rw_lock
= path
->locks
[level
];
5743 ret
= read_block_for_search(NULL
, root
, path
, &next
, level
,
5749 btrfs_release_path(path
);
5753 if (!path
->skip_locking
) {
5754 ret
= btrfs_try_tree_read_lock(next
);
5755 if (!ret
&& time_seq
) {
5757 * If we don't get the lock, we may be racing
5758 * with push_leaf_left, holding that lock while
5759 * itself waiting for the leaf we've currently
5760 * locked. To solve this situation, we give up
5761 * on our lock and cycle.
5763 free_extent_buffer(next
);
5764 btrfs_release_path(path
);
5769 btrfs_set_path_blocking(path
);
5770 btrfs_tree_read_lock(next
);
5771 btrfs_clear_path_blocking(path
, next
,
5774 next_rw_lock
= BTRFS_READ_LOCK
;
5778 path
->slots
[level
] = slot
;
5781 c
= path
->nodes
[level
];
5782 if (path
->locks
[level
])
5783 btrfs_tree_unlock_rw(c
, path
->locks
[level
]);
5785 free_extent_buffer(c
);
5786 path
->nodes
[level
] = next
;
5787 path
->slots
[level
] = 0;
5788 if (!path
->skip_locking
)
5789 path
->locks
[level
] = next_rw_lock
;
5793 ret
= read_block_for_search(NULL
, root
, path
, &next
, level
,
5799 btrfs_release_path(path
);
5803 if (!path
->skip_locking
) {
5804 ret
= btrfs_try_tree_read_lock(next
);
5806 btrfs_set_path_blocking(path
);
5807 btrfs_tree_read_lock(next
);
5808 btrfs_clear_path_blocking(path
, next
,
5811 next_rw_lock
= BTRFS_READ_LOCK
;
5816 unlock_up(path
, 0, 1, 0, NULL
);
5817 path
->leave_spinning
= old_spinning
;
5819 btrfs_set_path_blocking(path
);
5825 * this uses btrfs_prev_leaf to walk backwards in the tree, and keeps
5826 * searching until it gets past min_objectid or finds an item of 'type'
5828 * returns 0 if something is found, 1 if nothing was found and < 0 on error
5830 int btrfs_previous_item(struct btrfs_root
*root
,
5831 struct btrfs_path
*path
, u64 min_objectid
,
5834 struct btrfs_key found_key
;
5835 struct extent_buffer
*leaf
;
5840 if (path
->slots
[0] == 0) {
5841 btrfs_set_path_blocking(path
);
5842 ret
= btrfs_prev_leaf(root
, path
);
5848 leaf
= path
->nodes
[0];
5849 nritems
= btrfs_header_nritems(leaf
);
5852 if (path
->slots
[0] == nritems
)
5855 btrfs_item_key_to_cpu(leaf
, &found_key
, path
->slots
[0]);
5856 if (found_key
.objectid
< min_objectid
)
5858 if (found_key
.type
== type
)
5860 if (found_key
.objectid
== min_objectid
&&
5861 found_key
.type
< type
)
5868 * search in extent tree to find a previous Metadata/Data extent item with
5871 * returns 0 if something is found, 1 if nothing was found and < 0 on error
5873 int btrfs_previous_extent_item(struct btrfs_root
*root
,
5874 struct btrfs_path
*path
, u64 min_objectid
)
5876 struct btrfs_key found_key
;
5877 struct extent_buffer
*leaf
;
5882 if (path
->slots
[0] == 0) {
5883 btrfs_set_path_blocking(path
);
5884 ret
= btrfs_prev_leaf(root
, path
);
5890 leaf
= path
->nodes
[0];
5891 nritems
= btrfs_header_nritems(leaf
);
5894 if (path
->slots
[0] == nritems
)
5897 btrfs_item_key_to_cpu(leaf
, &found_key
, path
->slots
[0]);
5898 if (found_key
.objectid
< min_objectid
)
5900 if (found_key
.type
== BTRFS_EXTENT_ITEM_KEY
||
5901 found_key
.type
== BTRFS_METADATA_ITEM_KEY
)
5903 if (found_key
.objectid
== min_objectid
&&
5904 found_key
.type
< BTRFS_EXTENT_ITEM_KEY
)