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
= kcalloc(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
= kcalloc(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
= kcalloc(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
= kcalloc(nritems
, sizeof(struct tree_mod_elem
*), GFP_NOFS
);
912 for (i
= 0; i
< nritems
; i
++) {
913 tm_list
[i
] = alloc_tree_mod_elem(eb
, i
,
914 MOD_LOG_KEY_REMOVE_WHILE_FREEING
, GFP_NOFS
);
921 if (tree_mod_dont_log(fs_info
, eb
))
924 ret
= __tree_mod_log_free_eb(fs_info
, tm_list
, nritems
);
925 tree_mod_log_write_unlock(fs_info
);
933 for (i
= 0; i
< nritems
; i
++)
941 tree_mod_log_set_root_pointer(struct btrfs_root
*root
,
942 struct extent_buffer
*new_root_node
,
946 ret
= tree_mod_log_insert_root(root
->fs_info
, root
->node
,
947 new_root_node
, GFP_NOFS
, log_removal
);
952 * check if the tree block can be shared by multiple trees
954 int btrfs_block_can_be_shared(struct btrfs_root
*root
,
955 struct extent_buffer
*buf
)
958 * Tree blocks not in refernece counted trees and tree roots
959 * are never shared. If a block was allocated after the last
960 * snapshot and the block was not allocated by tree relocation,
961 * we know the block is not shared.
963 if (test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
964 buf
!= root
->node
&& buf
!= root
->commit_root
&&
965 (btrfs_header_generation(buf
) <=
966 btrfs_root_last_snapshot(&root
->root_item
) ||
967 btrfs_header_flag(buf
, BTRFS_HEADER_FLAG_RELOC
)))
969 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
970 if (test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
971 btrfs_header_backref_rev(buf
) < BTRFS_MIXED_BACKREF_REV
)
977 static noinline
int update_ref_for_cow(struct btrfs_trans_handle
*trans
,
978 struct btrfs_root
*root
,
979 struct extent_buffer
*buf
,
980 struct extent_buffer
*cow
,
990 * Backrefs update rules:
992 * Always use full backrefs for extent pointers in tree block
993 * allocated by tree relocation.
995 * If a shared tree block is no longer referenced by its owner
996 * tree (btrfs_header_owner(buf) == root->root_key.objectid),
997 * use full backrefs for extent pointers in tree block.
999 * If a tree block is been relocating
1000 * (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID),
1001 * use full backrefs for extent pointers in tree block.
1002 * The reason for this is some operations (such as drop tree)
1003 * are only allowed for blocks use full backrefs.
1006 if (btrfs_block_can_be_shared(root
, buf
)) {
1007 ret
= btrfs_lookup_extent_info(trans
, root
, buf
->start
,
1008 btrfs_header_level(buf
), 1,
1014 btrfs_std_error(root
->fs_info
, ret
);
1019 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
||
1020 btrfs_header_backref_rev(buf
) < BTRFS_MIXED_BACKREF_REV
)
1021 flags
= BTRFS_BLOCK_FLAG_FULL_BACKREF
;
1026 owner
= btrfs_header_owner(buf
);
1027 BUG_ON(owner
== BTRFS_TREE_RELOC_OBJECTID
&&
1028 !(flags
& BTRFS_BLOCK_FLAG_FULL_BACKREF
));
1031 if ((owner
== root
->root_key
.objectid
||
1032 root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
) &&
1033 !(flags
& BTRFS_BLOCK_FLAG_FULL_BACKREF
)) {
1034 ret
= btrfs_inc_ref(trans
, root
, buf
, 1);
1035 BUG_ON(ret
); /* -ENOMEM */
1037 if (root
->root_key
.objectid
==
1038 BTRFS_TREE_RELOC_OBJECTID
) {
1039 ret
= btrfs_dec_ref(trans
, root
, buf
, 0);
1040 BUG_ON(ret
); /* -ENOMEM */
1041 ret
= btrfs_inc_ref(trans
, root
, cow
, 1);
1042 BUG_ON(ret
); /* -ENOMEM */
1044 new_flags
|= BTRFS_BLOCK_FLAG_FULL_BACKREF
;
1047 if (root
->root_key
.objectid
==
1048 BTRFS_TREE_RELOC_OBJECTID
)
1049 ret
= btrfs_inc_ref(trans
, root
, cow
, 1);
1051 ret
= btrfs_inc_ref(trans
, root
, cow
, 0);
1052 BUG_ON(ret
); /* -ENOMEM */
1054 if (new_flags
!= 0) {
1055 int level
= btrfs_header_level(buf
);
1057 ret
= btrfs_set_disk_extent_flags(trans
, root
,
1060 new_flags
, level
, 0);
1065 if (flags
& BTRFS_BLOCK_FLAG_FULL_BACKREF
) {
1066 if (root
->root_key
.objectid
==
1067 BTRFS_TREE_RELOC_OBJECTID
)
1068 ret
= btrfs_inc_ref(trans
, root
, cow
, 1);
1070 ret
= btrfs_inc_ref(trans
, root
, cow
, 0);
1071 BUG_ON(ret
); /* -ENOMEM */
1072 ret
= btrfs_dec_ref(trans
, root
, buf
, 1);
1073 BUG_ON(ret
); /* -ENOMEM */
1075 clean_tree_block(trans
, root
->fs_info
, buf
);
1082 * does the dirty work in cow of a single block. The parent block (if
1083 * supplied) is updated to point to the new cow copy. The new buffer is marked
1084 * dirty and returned locked. If you modify the block it needs to be marked
1087 * search_start -- an allocation hint for the new block
1089 * empty_size -- a hint that you plan on doing more cow. This is the size in
1090 * bytes the allocator should try to find free next to the block it returns.
1091 * This is just a hint and may be ignored by the allocator.
1093 static noinline
int __btrfs_cow_block(struct btrfs_trans_handle
*trans
,
1094 struct btrfs_root
*root
,
1095 struct extent_buffer
*buf
,
1096 struct extent_buffer
*parent
, int parent_slot
,
1097 struct extent_buffer
**cow_ret
,
1098 u64 search_start
, u64 empty_size
)
1100 struct btrfs_disk_key disk_key
;
1101 struct extent_buffer
*cow
;
1104 int unlock_orig
= 0;
1107 if (*cow_ret
== buf
)
1110 btrfs_assert_tree_locked(buf
);
1112 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
1113 trans
->transid
!= root
->fs_info
->running_transaction
->transid
);
1114 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
1115 trans
->transid
!= root
->last_trans
);
1117 level
= btrfs_header_level(buf
);
1120 btrfs_item_key(buf
, &disk_key
, 0);
1122 btrfs_node_key(buf
, &disk_key
, 0);
1124 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
) {
1126 parent_start
= parent
->start
;
1132 cow
= btrfs_alloc_tree_block(trans
, root
, parent_start
,
1133 root
->root_key
.objectid
, &disk_key
, level
,
1134 search_start
, empty_size
);
1136 return PTR_ERR(cow
);
1138 /* cow is set to blocking by btrfs_init_new_buffer */
1140 copy_extent_buffer(cow
, buf
, 0, 0, cow
->len
);
1141 btrfs_set_header_bytenr(cow
, cow
->start
);
1142 btrfs_set_header_generation(cow
, trans
->transid
);
1143 btrfs_set_header_backref_rev(cow
, BTRFS_MIXED_BACKREF_REV
);
1144 btrfs_clear_header_flag(cow
, BTRFS_HEADER_FLAG_WRITTEN
|
1145 BTRFS_HEADER_FLAG_RELOC
);
1146 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
)
1147 btrfs_set_header_flag(cow
, BTRFS_HEADER_FLAG_RELOC
);
1149 btrfs_set_header_owner(cow
, root
->root_key
.objectid
);
1151 write_extent_buffer(cow
, root
->fs_info
->fsid
, btrfs_header_fsid(),
1154 ret
= update_ref_for_cow(trans
, root
, buf
, cow
, &last_ref
);
1156 btrfs_abort_transaction(trans
, root
, ret
);
1160 if (test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
)) {
1161 ret
= btrfs_reloc_cow_block(trans
, root
, buf
, cow
);
1166 if (buf
== root
->node
) {
1167 WARN_ON(parent
&& parent
!= buf
);
1168 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
||
1169 btrfs_header_backref_rev(buf
) < BTRFS_MIXED_BACKREF_REV
)
1170 parent_start
= buf
->start
;
1174 extent_buffer_get(cow
);
1175 tree_mod_log_set_root_pointer(root
, cow
, 1);
1176 rcu_assign_pointer(root
->node
, cow
);
1178 btrfs_free_tree_block(trans
, root
, buf
, parent_start
,
1180 free_extent_buffer(buf
);
1181 add_root_to_dirty_list(root
);
1183 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
)
1184 parent_start
= parent
->start
;
1188 WARN_ON(trans
->transid
!= btrfs_header_generation(parent
));
1189 tree_mod_log_insert_key(root
->fs_info
, parent
, parent_slot
,
1190 MOD_LOG_KEY_REPLACE
, GFP_NOFS
);
1191 btrfs_set_node_blockptr(parent
, parent_slot
,
1193 btrfs_set_node_ptr_generation(parent
, parent_slot
,
1195 btrfs_mark_buffer_dirty(parent
);
1197 ret
= tree_mod_log_free_eb(root
->fs_info
, buf
);
1199 btrfs_abort_transaction(trans
, root
, ret
);
1203 btrfs_free_tree_block(trans
, root
, buf
, parent_start
,
1207 btrfs_tree_unlock(buf
);
1208 free_extent_buffer_stale(buf
);
1209 btrfs_mark_buffer_dirty(cow
);
1215 * returns the logical address of the oldest predecessor of the given root.
1216 * entries older than time_seq are ignored.
1218 static struct tree_mod_elem
*
1219 __tree_mod_log_oldest_root(struct btrfs_fs_info
*fs_info
,
1220 struct extent_buffer
*eb_root
, u64 time_seq
)
1222 struct tree_mod_elem
*tm
;
1223 struct tree_mod_elem
*found
= NULL
;
1224 u64 root_logical
= eb_root
->start
;
1231 * the very last operation that's logged for a root is the replacement
1232 * operation (if it is replaced at all). this has the index of the *new*
1233 * root, making it the very first operation that's logged for this root.
1236 tm
= tree_mod_log_search_oldest(fs_info
, root_logical
,
1241 * if there are no tree operation for the oldest root, we simply
1242 * return it. this should only happen if that (old) root is at
1249 * if there's an operation that's not a root replacement, we
1250 * found the oldest version of our root. normally, we'll find a
1251 * MOD_LOG_KEY_REMOVE_WHILE_FREEING operation here.
1253 if (tm
->op
!= MOD_LOG_ROOT_REPLACE
)
1257 root_logical
= tm
->old_root
.logical
;
1261 /* if there's no old root to return, return what we found instead */
1269 * tm is a pointer to the first operation to rewind within eb. then, all
1270 * previous operations will be rewinded (until we reach something older than
1274 __tree_mod_log_rewind(struct btrfs_fs_info
*fs_info
, struct extent_buffer
*eb
,
1275 u64 time_seq
, struct tree_mod_elem
*first_tm
)
1278 struct rb_node
*next
;
1279 struct tree_mod_elem
*tm
= first_tm
;
1280 unsigned long o_dst
;
1281 unsigned long o_src
;
1282 unsigned long p_size
= sizeof(struct btrfs_key_ptr
);
1284 n
= btrfs_header_nritems(eb
);
1285 tree_mod_log_read_lock(fs_info
);
1286 while (tm
&& tm
->seq
>= time_seq
) {
1288 * all the operations are recorded with the operator used for
1289 * the modification. as we're going backwards, we do the
1290 * opposite of each operation here.
1293 case MOD_LOG_KEY_REMOVE_WHILE_FREEING
:
1294 BUG_ON(tm
->slot
< n
);
1296 case MOD_LOG_KEY_REMOVE_WHILE_MOVING
:
1297 case MOD_LOG_KEY_REMOVE
:
1298 btrfs_set_node_key(eb
, &tm
->key
, tm
->slot
);
1299 btrfs_set_node_blockptr(eb
, tm
->slot
, tm
->blockptr
);
1300 btrfs_set_node_ptr_generation(eb
, tm
->slot
,
1304 case MOD_LOG_KEY_REPLACE
:
1305 BUG_ON(tm
->slot
>= n
);
1306 btrfs_set_node_key(eb
, &tm
->key
, tm
->slot
);
1307 btrfs_set_node_blockptr(eb
, tm
->slot
, tm
->blockptr
);
1308 btrfs_set_node_ptr_generation(eb
, tm
->slot
,
1311 case MOD_LOG_KEY_ADD
:
1312 /* if a move operation is needed it's in the log */
1315 case MOD_LOG_MOVE_KEYS
:
1316 o_dst
= btrfs_node_key_ptr_offset(tm
->slot
);
1317 o_src
= btrfs_node_key_ptr_offset(tm
->move
.dst_slot
);
1318 memmove_extent_buffer(eb
, o_dst
, o_src
,
1319 tm
->move
.nr_items
* p_size
);
1321 case MOD_LOG_ROOT_REPLACE
:
1323 * this operation is special. for roots, this must be
1324 * handled explicitly before rewinding.
1325 * for non-roots, this operation may exist if the node
1326 * was a root: root A -> child B; then A gets empty and
1327 * B is promoted to the new root. in the mod log, we'll
1328 * have a root-replace operation for B, a tree block
1329 * that is no root. we simply ignore that operation.
1333 next
= rb_next(&tm
->node
);
1336 tm
= container_of(next
, struct tree_mod_elem
, node
);
1337 if (tm
->index
!= first_tm
->index
)
1340 tree_mod_log_read_unlock(fs_info
);
1341 btrfs_set_header_nritems(eb
, n
);
1345 * Called with eb read locked. If the buffer cannot be rewinded, the same buffer
1346 * is returned. If rewind operations happen, a fresh buffer is returned. The
1347 * returned buffer is always read-locked. If the returned buffer is not the
1348 * input buffer, the lock on the input buffer is released and the input buffer
1349 * is freed (its refcount is decremented).
1351 static struct extent_buffer
*
1352 tree_mod_log_rewind(struct btrfs_fs_info
*fs_info
, struct btrfs_path
*path
,
1353 struct extent_buffer
*eb
, u64 time_seq
)
1355 struct extent_buffer
*eb_rewin
;
1356 struct tree_mod_elem
*tm
;
1361 if (btrfs_header_level(eb
) == 0)
1364 tm
= tree_mod_log_search(fs_info
, eb
->start
, time_seq
);
1368 btrfs_set_path_blocking(path
);
1369 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1371 if (tm
->op
== MOD_LOG_KEY_REMOVE_WHILE_FREEING
) {
1372 BUG_ON(tm
->slot
!= 0);
1373 eb_rewin
= alloc_dummy_extent_buffer(fs_info
, eb
->start
);
1375 btrfs_tree_read_unlock_blocking(eb
);
1376 free_extent_buffer(eb
);
1379 btrfs_set_header_bytenr(eb_rewin
, eb
->start
);
1380 btrfs_set_header_backref_rev(eb_rewin
,
1381 btrfs_header_backref_rev(eb
));
1382 btrfs_set_header_owner(eb_rewin
, btrfs_header_owner(eb
));
1383 btrfs_set_header_level(eb_rewin
, btrfs_header_level(eb
));
1385 eb_rewin
= btrfs_clone_extent_buffer(eb
);
1387 btrfs_tree_read_unlock_blocking(eb
);
1388 free_extent_buffer(eb
);
1393 btrfs_clear_path_blocking(path
, NULL
, BTRFS_READ_LOCK
);
1394 btrfs_tree_read_unlock_blocking(eb
);
1395 free_extent_buffer(eb
);
1397 extent_buffer_get(eb_rewin
);
1398 btrfs_tree_read_lock(eb_rewin
);
1399 __tree_mod_log_rewind(fs_info
, eb_rewin
, time_seq
, tm
);
1400 WARN_ON(btrfs_header_nritems(eb_rewin
) >
1401 BTRFS_NODEPTRS_PER_BLOCK(fs_info
->tree_root
));
1407 * get_old_root() rewinds the state of @root's root node to the given @time_seq
1408 * value. If there are no changes, the current root->root_node is returned. If
1409 * anything changed in between, there's a fresh buffer allocated on which the
1410 * rewind operations are done. In any case, the returned buffer is read locked.
1411 * Returns NULL on error (with no locks held).
1413 static inline struct extent_buffer
*
1414 get_old_root(struct btrfs_root
*root
, u64 time_seq
)
1416 struct tree_mod_elem
*tm
;
1417 struct extent_buffer
*eb
= NULL
;
1418 struct extent_buffer
*eb_root
;
1419 struct extent_buffer
*old
;
1420 struct tree_mod_root
*old_root
= NULL
;
1421 u64 old_generation
= 0;
1424 eb_root
= btrfs_read_lock_root_node(root
);
1425 tm
= __tree_mod_log_oldest_root(root
->fs_info
, eb_root
, time_seq
);
1429 if (tm
->op
== MOD_LOG_ROOT_REPLACE
) {
1430 old_root
= &tm
->old_root
;
1431 old_generation
= tm
->generation
;
1432 logical
= old_root
->logical
;
1434 logical
= eb_root
->start
;
1437 tm
= tree_mod_log_search(root
->fs_info
, logical
, time_seq
);
1438 if (old_root
&& tm
&& tm
->op
!= MOD_LOG_KEY_REMOVE_WHILE_FREEING
) {
1439 btrfs_tree_read_unlock(eb_root
);
1440 free_extent_buffer(eb_root
);
1441 old
= read_tree_block(root
, logical
, 0);
1442 if (WARN_ON(!old
|| !extent_buffer_uptodate(old
))) {
1443 free_extent_buffer(old
);
1444 btrfs_warn(root
->fs_info
,
1445 "failed to read tree block %llu from get_old_root", logical
);
1447 eb
= btrfs_clone_extent_buffer(old
);
1448 free_extent_buffer(old
);
1450 } else if (old_root
) {
1451 btrfs_tree_read_unlock(eb_root
);
1452 free_extent_buffer(eb_root
);
1453 eb
= alloc_dummy_extent_buffer(root
->fs_info
, logical
);
1455 btrfs_set_lock_blocking_rw(eb_root
, BTRFS_READ_LOCK
);
1456 eb
= btrfs_clone_extent_buffer(eb_root
);
1457 btrfs_tree_read_unlock_blocking(eb_root
);
1458 free_extent_buffer(eb_root
);
1463 extent_buffer_get(eb
);
1464 btrfs_tree_read_lock(eb
);
1466 btrfs_set_header_bytenr(eb
, eb
->start
);
1467 btrfs_set_header_backref_rev(eb
, BTRFS_MIXED_BACKREF_REV
);
1468 btrfs_set_header_owner(eb
, btrfs_header_owner(eb_root
));
1469 btrfs_set_header_level(eb
, old_root
->level
);
1470 btrfs_set_header_generation(eb
, old_generation
);
1473 __tree_mod_log_rewind(root
->fs_info
, eb
, time_seq
, tm
);
1475 WARN_ON(btrfs_header_level(eb
) != 0);
1476 WARN_ON(btrfs_header_nritems(eb
) > BTRFS_NODEPTRS_PER_BLOCK(root
));
1481 int btrfs_old_root_level(struct btrfs_root
*root
, u64 time_seq
)
1483 struct tree_mod_elem
*tm
;
1485 struct extent_buffer
*eb_root
= btrfs_root_node(root
);
1487 tm
= __tree_mod_log_oldest_root(root
->fs_info
, eb_root
, time_seq
);
1488 if (tm
&& tm
->op
== MOD_LOG_ROOT_REPLACE
) {
1489 level
= tm
->old_root
.level
;
1491 level
= btrfs_header_level(eb_root
);
1493 free_extent_buffer(eb_root
);
1498 static inline int should_cow_block(struct btrfs_trans_handle
*trans
,
1499 struct btrfs_root
*root
,
1500 struct extent_buffer
*buf
)
1502 if (btrfs_test_is_dummy_root(root
))
1505 /* ensure we can see the force_cow */
1509 * We do not need to cow a block if
1510 * 1) this block is not created or changed in this transaction;
1511 * 2) this block does not belong to TREE_RELOC tree;
1512 * 3) the root is not forced COW.
1514 * What is forced COW:
1515 * when we create snapshot during commiting the transaction,
1516 * after we've finished coping src root, we must COW the shared
1517 * block to ensure the metadata consistency.
1519 if (btrfs_header_generation(buf
) == trans
->transid
&&
1520 !btrfs_header_flag(buf
, BTRFS_HEADER_FLAG_WRITTEN
) &&
1521 !(root
->root_key
.objectid
!= BTRFS_TREE_RELOC_OBJECTID
&&
1522 btrfs_header_flag(buf
, BTRFS_HEADER_FLAG_RELOC
)) &&
1523 !test_bit(BTRFS_ROOT_FORCE_COW
, &root
->state
))
1529 * cows a single block, see __btrfs_cow_block for the real work.
1530 * This version of it has extra checks so that a block isn't cow'd more than
1531 * once per transaction, as long as it hasn't been written yet
1533 noinline
int btrfs_cow_block(struct btrfs_trans_handle
*trans
,
1534 struct btrfs_root
*root
, struct extent_buffer
*buf
,
1535 struct extent_buffer
*parent
, int parent_slot
,
1536 struct extent_buffer
**cow_ret
)
1541 if (trans
->transaction
!= root
->fs_info
->running_transaction
)
1542 WARN(1, KERN_CRIT
"trans %llu running %llu\n",
1544 root
->fs_info
->running_transaction
->transid
);
1546 if (trans
->transid
!= root
->fs_info
->generation
)
1547 WARN(1, KERN_CRIT
"trans %llu running %llu\n",
1548 trans
->transid
, root
->fs_info
->generation
);
1550 if (!should_cow_block(trans
, root
, buf
)) {
1555 search_start
= buf
->start
& ~((u64
)(1024 * 1024 * 1024) - 1);
1558 btrfs_set_lock_blocking(parent
);
1559 btrfs_set_lock_blocking(buf
);
1561 ret
= __btrfs_cow_block(trans
, root
, buf
, parent
,
1562 parent_slot
, cow_ret
, search_start
, 0);
1564 trace_btrfs_cow_block(root
, buf
, *cow_ret
);
1570 * helper function for defrag to decide if two blocks pointed to by a
1571 * node are actually close by
1573 static int close_blocks(u64 blocknr
, u64 other
, u32 blocksize
)
1575 if (blocknr
< other
&& other
- (blocknr
+ blocksize
) < 32768)
1577 if (blocknr
> other
&& blocknr
- (other
+ blocksize
) < 32768)
1583 * compare two keys in a memcmp fashion
1585 static int comp_keys(struct btrfs_disk_key
*disk
, struct btrfs_key
*k2
)
1587 struct btrfs_key k1
;
1589 btrfs_disk_key_to_cpu(&k1
, disk
);
1591 return btrfs_comp_cpu_keys(&k1
, k2
);
1595 * same as comp_keys only with two btrfs_key's
1597 int btrfs_comp_cpu_keys(struct btrfs_key
*k1
, struct btrfs_key
*k2
)
1599 if (k1
->objectid
> k2
->objectid
)
1601 if (k1
->objectid
< k2
->objectid
)
1603 if (k1
->type
> k2
->type
)
1605 if (k1
->type
< k2
->type
)
1607 if (k1
->offset
> k2
->offset
)
1609 if (k1
->offset
< k2
->offset
)
1615 * this is used by the defrag code to go through all the
1616 * leaves pointed to by a node and reallocate them so that
1617 * disk order is close to key order
1619 int btrfs_realloc_node(struct btrfs_trans_handle
*trans
,
1620 struct btrfs_root
*root
, struct extent_buffer
*parent
,
1621 int start_slot
, u64
*last_ret
,
1622 struct btrfs_key
*progress
)
1624 struct extent_buffer
*cur
;
1627 u64 search_start
= *last_ret
;
1637 int progress_passed
= 0;
1638 struct btrfs_disk_key disk_key
;
1640 parent_level
= btrfs_header_level(parent
);
1642 WARN_ON(trans
->transaction
!= root
->fs_info
->running_transaction
);
1643 WARN_ON(trans
->transid
!= root
->fs_info
->generation
);
1645 parent_nritems
= btrfs_header_nritems(parent
);
1646 blocksize
= root
->nodesize
;
1647 end_slot
= parent_nritems
- 1;
1649 if (parent_nritems
<= 1)
1652 btrfs_set_lock_blocking(parent
);
1654 for (i
= start_slot
; i
<= end_slot
; i
++) {
1657 btrfs_node_key(parent
, &disk_key
, i
);
1658 if (!progress_passed
&& comp_keys(&disk_key
, progress
) < 0)
1661 progress_passed
= 1;
1662 blocknr
= btrfs_node_blockptr(parent
, i
);
1663 gen
= btrfs_node_ptr_generation(parent
, i
);
1664 if (last_block
== 0)
1665 last_block
= blocknr
;
1668 other
= btrfs_node_blockptr(parent
, i
- 1);
1669 close
= close_blocks(blocknr
, other
, blocksize
);
1671 if (!close
&& i
< end_slot
) {
1672 other
= btrfs_node_blockptr(parent
, i
+ 1);
1673 close
= close_blocks(blocknr
, other
, blocksize
);
1676 last_block
= blocknr
;
1680 cur
= btrfs_find_tree_block(root
->fs_info
, blocknr
);
1682 uptodate
= btrfs_buffer_uptodate(cur
, gen
, 0);
1685 if (!cur
|| !uptodate
) {
1687 cur
= read_tree_block(root
, blocknr
, gen
);
1688 if (!cur
|| !extent_buffer_uptodate(cur
)) {
1689 free_extent_buffer(cur
);
1692 } else if (!uptodate
) {
1693 err
= btrfs_read_buffer(cur
, gen
);
1695 free_extent_buffer(cur
);
1700 if (search_start
== 0)
1701 search_start
= last_block
;
1703 btrfs_tree_lock(cur
);
1704 btrfs_set_lock_blocking(cur
);
1705 err
= __btrfs_cow_block(trans
, root
, cur
, parent
, i
,
1708 (end_slot
- i
) * blocksize
));
1710 btrfs_tree_unlock(cur
);
1711 free_extent_buffer(cur
);
1714 search_start
= cur
->start
;
1715 last_block
= cur
->start
;
1716 *last_ret
= search_start
;
1717 btrfs_tree_unlock(cur
);
1718 free_extent_buffer(cur
);
1724 * The leaf data grows from end-to-front in the node.
1725 * this returns the address of the start of the last item,
1726 * which is the stop of the leaf data stack
1728 static inline unsigned int leaf_data_end(struct btrfs_root
*root
,
1729 struct extent_buffer
*leaf
)
1731 u32 nr
= btrfs_header_nritems(leaf
);
1733 return BTRFS_LEAF_DATA_SIZE(root
);
1734 return btrfs_item_offset_nr(leaf
, nr
- 1);
1739 * search for key in the extent_buffer. The items start at offset p,
1740 * and they are item_size apart. There are 'max' items in p.
1742 * the slot in the array is returned via slot, and it points to
1743 * the place where you would insert key if it is not found in
1746 * slot may point to max if the key is bigger than all of the keys
1748 static noinline
int generic_bin_search(struct extent_buffer
*eb
,
1750 int item_size
, struct btrfs_key
*key
,
1757 struct btrfs_disk_key
*tmp
= NULL
;
1758 struct btrfs_disk_key unaligned
;
1759 unsigned long offset
;
1761 unsigned long map_start
= 0;
1762 unsigned long map_len
= 0;
1765 while (low
< high
) {
1766 mid
= (low
+ high
) / 2;
1767 offset
= p
+ mid
* item_size
;
1769 if (!kaddr
|| offset
< map_start
||
1770 (offset
+ sizeof(struct btrfs_disk_key
)) >
1771 map_start
+ map_len
) {
1773 err
= map_private_extent_buffer(eb
, offset
,
1774 sizeof(struct btrfs_disk_key
),
1775 &kaddr
, &map_start
, &map_len
);
1778 tmp
= (struct btrfs_disk_key
*)(kaddr
+ offset
-
1781 read_extent_buffer(eb
, &unaligned
,
1782 offset
, sizeof(unaligned
));
1787 tmp
= (struct btrfs_disk_key
*)(kaddr
+ offset
-
1790 ret
= comp_keys(tmp
, key
);
1806 * simple bin_search frontend that does the right thing for
1809 static int bin_search(struct extent_buffer
*eb
, struct btrfs_key
*key
,
1810 int level
, int *slot
)
1813 return generic_bin_search(eb
,
1814 offsetof(struct btrfs_leaf
, items
),
1815 sizeof(struct btrfs_item
),
1816 key
, btrfs_header_nritems(eb
),
1819 return generic_bin_search(eb
,
1820 offsetof(struct btrfs_node
, ptrs
),
1821 sizeof(struct btrfs_key_ptr
),
1822 key
, btrfs_header_nritems(eb
),
1826 int btrfs_bin_search(struct extent_buffer
*eb
, struct btrfs_key
*key
,
1827 int level
, int *slot
)
1829 return bin_search(eb
, key
, level
, slot
);
1832 static void root_add_used(struct btrfs_root
*root
, u32 size
)
1834 spin_lock(&root
->accounting_lock
);
1835 btrfs_set_root_used(&root
->root_item
,
1836 btrfs_root_used(&root
->root_item
) + size
);
1837 spin_unlock(&root
->accounting_lock
);
1840 static void root_sub_used(struct btrfs_root
*root
, u32 size
)
1842 spin_lock(&root
->accounting_lock
);
1843 btrfs_set_root_used(&root
->root_item
,
1844 btrfs_root_used(&root
->root_item
) - size
);
1845 spin_unlock(&root
->accounting_lock
);
1848 /* given a node and slot number, this reads the blocks it points to. The
1849 * extent buffer is returned with a reference taken (but unlocked).
1850 * NULL is returned on error.
1852 static noinline
struct extent_buffer
*read_node_slot(struct btrfs_root
*root
,
1853 struct extent_buffer
*parent
, int slot
)
1855 int level
= btrfs_header_level(parent
);
1856 struct extent_buffer
*eb
;
1860 if (slot
>= btrfs_header_nritems(parent
))
1865 eb
= read_tree_block(root
, btrfs_node_blockptr(parent
, slot
),
1866 btrfs_node_ptr_generation(parent
, slot
));
1867 if (eb
&& !extent_buffer_uptodate(eb
)) {
1868 free_extent_buffer(eb
);
1876 * node level balancing, used to make sure nodes are in proper order for
1877 * item deletion. We balance from the top down, so we have to make sure
1878 * that a deletion won't leave an node completely empty later on.
1880 static noinline
int balance_level(struct btrfs_trans_handle
*trans
,
1881 struct btrfs_root
*root
,
1882 struct btrfs_path
*path
, int level
)
1884 struct extent_buffer
*right
= NULL
;
1885 struct extent_buffer
*mid
;
1886 struct extent_buffer
*left
= NULL
;
1887 struct extent_buffer
*parent
= NULL
;
1891 int orig_slot
= path
->slots
[level
];
1897 mid
= path
->nodes
[level
];
1899 WARN_ON(path
->locks
[level
] != BTRFS_WRITE_LOCK
&&
1900 path
->locks
[level
] != BTRFS_WRITE_LOCK_BLOCKING
);
1901 WARN_ON(btrfs_header_generation(mid
) != trans
->transid
);
1903 orig_ptr
= btrfs_node_blockptr(mid
, orig_slot
);
1905 if (level
< BTRFS_MAX_LEVEL
- 1) {
1906 parent
= path
->nodes
[level
+ 1];
1907 pslot
= path
->slots
[level
+ 1];
1911 * deal with the case where there is only one pointer in the root
1912 * by promoting the node below to a root
1915 struct extent_buffer
*child
;
1917 if (btrfs_header_nritems(mid
) != 1)
1920 /* promote the child to a root */
1921 child
= read_node_slot(root
, mid
, 0);
1924 btrfs_std_error(root
->fs_info
, ret
);
1928 btrfs_tree_lock(child
);
1929 btrfs_set_lock_blocking(child
);
1930 ret
= btrfs_cow_block(trans
, root
, child
, mid
, 0, &child
);
1932 btrfs_tree_unlock(child
);
1933 free_extent_buffer(child
);
1937 tree_mod_log_set_root_pointer(root
, child
, 1);
1938 rcu_assign_pointer(root
->node
, child
);
1940 add_root_to_dirty_list(root
);
1941 btrfs_tree_unlock(child
);
1943 path
->locks
[level
] = 0;
1944 path
->nodes
[level
] = NULL
;
1945 clean_tree_block(trans
, root
->fs_info
, mid
);
1946 btrfs_tree_unlock(mid
);
1947 /* once for the path */
1948 free_extent_buffer(mid
);
1950 root_sub_used(root
, mid
->len
);
1951 btrfs_free_tree_block(trans
, root
, mid
, 0, 1);
1952 /* once for the root ptr */
1953 free_extent_buffer_stale(mid
);
1956 if (btrfs_header_nritems(mid
) >
1957 BTRFS_NODEPTRS_PER_BLOCK(root
) / 4)
1960 left
= read_node_slot(root
, parent
, pslot
- 1);
1962 btrfs_tree_lock(left
);
1963 btrfs_set_lock_blocking(left
);
1964 wret
= btrfs_cow_block(trans
, root
, left
,
1965 parent
, pslot
- 1, &left
);
1971 right
= read_node_slot(root
, parent
, pslot
+ 1);
1973 btrfs_tree_lock(right
);
1974 btrfs_set_lock_blocking(right
);
1975 wret
= btrfs_cow_block(trans
, root
, right
,
1976 parent
, pslot
+ 1, &right
);
1983 /* first, try to make some room in the middle buffer */
1985 orig_slot
+= btrfs_header_nritems(left
);
1986 wret
= push_node_left(trans
, root
, left
, mid
, 1);
1992 * then try to empty the right most buffer into the middle
1995 wret
= push_node_left(trans
, root
, mid
, right
, 1);
1996 if (wret
< 0 && wret
!= -ENOSPC
)
1998 if (btrfs_header_nritems(right
) == 0) {
1999 clean_tree_block(trans
, root
->fs_info
, right
);
2000 btrfs_tree_unlock(right
);
2001 del_ptr(root
, path
, level
+ 1, pslot
+ 1);
2002 root_sub_used(root
, right
->len
);
2003 btrfs_free_tree_block(trans
, root
, right
, 0, 1);
2004 free_extent_buffer_stale(right
);
2007 struct btrfs_disk_key right_key
;
2008 btrfs_node_key(right
, &right_key
, 0);
2009 tree_mod_log_set_node_key(root
->fs_info
, parent
,
2011 btrfs_set_node_key(parent
, &right_key
, pslot
+ 1);
2012 btrfs_mark_buffer_dirty(parent
);
2015 if (btrfs_header_nritems(mid
) == 1) {
2017 * we're not allowed to leave a node with one item in the
2018 * tree during a delete. A deletion from lower in the tree
2019 * could try to delete the only pointer in this node.
2020 * So, pull some keys from the left.
2021 * There has to be a left pointer at this point because
2022 * otherwise we would have pulled some pointers from the
2027 btrfs_std_error(root
->fs_info
, ret
);
2030 wret
= balance_node_right(trans
, root
, mid
, left
);
2036 wret
= push_node_left(trans
, root
, left
, mid
, 1);
2042 if (btrfs_header_nritems(mid
) == 0) {
2043 clean_tree_block(trans
, root
->fs_info
, mid
);
2044 btrfs_tree_unlock(mid
);
2045 del_ptr(root
, path
, level
+ 1, pslot
);
2046 root_sub_used(root
, mid
->len
);
2047 btrfs_free_tree_block(trans
, root
, mid
, 0, 1);
2048 free_extent_buffer_stale(mid
);
2051 /* update the parent key to reflect our changes */
2052 struct btrfs_disk_key mid_key
;
2053 btrfs_node_key(mid
, &mid_key
, 0);
2054 tree_mod_log_set_node_key(root
->fs_info
, parent
,
2056 btrfs_set_node_key(parent
, &mid_key
, pslot
);
2057 btrfs_mark_buffer_dirty(parent
);
2060 /* update the path */
2062 if (btrfs_header_nritems(left
) > orig_slot
) {
2063 extent_buffer_get(left
);
2064 /* left was locked after cow */
2065 path
->nodes
[level
] = left
;
2066 path
->slots
[level
+ 1] -= 1;
2067 path
->slots
[level
] = orig_slot
;
2069 btrfs_tree_unlock(mid
);
2070 free_extent_buffer(mid
);
2073 orig_slot
-= btrfs_header_nritems(left
);
2074 path
->slots
[level
] = orig_slot
;
2077 /* double check we haven't messed things up */
2079 btrfs_node_blockptr(path
->nodes
[level
], path
->slots
[level
]))
2083 btrfs_tree_unlock(right
);
2084 free_extent_buffer(right
);
2087 if (path
->nodes
[level
] != left
)
2088 btrfs_tree_unlock(left
);
2089 free_extent_buffer(left
);
2094 /* Node balancing for insertion. Here we only split or push nodes around
2095 * when they are completely full. This is also done top down, so we
2096 * have to be pessimistic.
2098 static noinline
int push_nodes_for_insert(struct btrfs_trans_handle
*trans
,
2099 struct btrfs_root
*root
,
2100 struct btrfs_path
*path
, int level
)
2102 struct extent_buffer
*right
= NULL
;
2103 struct extent_buffer
*mid
;
2104 struct extent_buffer
*left
= NULL
;
2105 struct extent_buffer
*parent
= NULL
;
2109 int orig_slot
= path
->slots
[level
];
2114 mid
= path
->nodes
[level
];
2115 WARN_ON(btrfs_header_generation(mid
) != trans
->transid
);
2117 if (level
< BTRFS_MAX_LEVEL
- 1) {
2118 parent
= path
->nodes
[level
+ 1];
2119 pslot
= path
->slots
[level
+ 1];
2125 left
= read_node_slot(root
, parent
, pslot
- 1);
2127 /* first, try to make some room in the middle buffer */
2131 btrfs_tree_lock(left
);
2132 btrfs_set_lock_blocking(left
);
2134 left_nr
= btrfs_header_nritems(left
);
2135 if (left_nr
>= BTRFS_NODEPTRS_PER_BLOCK(root
) - 1) {
2138 ret
= btrfs_cow_block(trans
, root
, left
, parent
,
2143 wret
= push_node_left(trans
, root
,
2150 struct btrfs_disk_key disk_key
;
2151 orig_slot
+= left_nr
;
2152 btrfs_node_key(mid
, &disk_key
, 0);
2153 tree_mod_log_set_node_key(root
->fs_info
, parent
,
2155 btrfs_set_node_key(parent
, &disk_key
, pslot
);
2156 btrfs_mark_buffer_dirty(parent
);
2157 if (btrfs_header_nritems(left
) > orig_slot
) {
2158 path
->nodes
[level
] = left
;
2159 path
->slots
[level
+ 1] -= 1;
2160 path
->slots
[level
] = orig_slot
;
2161 btrfs_tree_unlock(mid
);
2162 free_extent_buffer(mid
);
2165 btrfs_header_nritems(left
);
2166 path
->slots
[level
] = orig_slot
;
2167 btrfs_tree_unlock(left
);
2168 free_extent_buffer(left
);
2172 btrfs_tree_unlock(left
);
2173 free_extent_buffer(left
);
2175 right
= read_node_slot(root
, parent
, pslot
+ 1);
2178 * then try to empty the right most buffer into the middle
2183 btrfs_tree_lock(right
);
2184 btrfs_set_lock_blocking(right
);
2186 right_nr
= btrfs_header_nritems(right
);
2187 if (right_nr
>= BTRFS_NODEPTRS_PER_BLOCK(root
) - 1) {
2190 ret
= btrfs_cow_block(trans
, root
, right
,
2196 wret
= balance_node_right(trans
, root
,
2203 struct btrfs_disk_key disk_key
;
2205 btrfs_node_key(right
, &disk_key
, 0);
2206 tree_mod_log_set_node_key(root
->fs_info
, parent
,
2208 btrfs_set_node_key(parent
, &disk_key
, pslot
+ 1);
2209 btrfs_mark_buffer_dirty(parent
);
2211 if (btrfs_header_nritems(mid
) <= orig_slot
) {
2212 path
->nodes
[level
] = right
;
2213 path
->slots
[level
+ 1] += 1;
2214 path
->slots
[level
] = orig_slot
-
2215 btrfs_header_nritems(mid
);
2216 btrfs_tree_unlock(mid
);
2217 free_extent_buffer(mid
);
2219 btrfs_tree_unlock(right
);
2220 free_extent_buffer(right
);
2224 btrfs_tree_unlock(right
);
2225 free_extent_buffer(right
);
2231 * readahead one full node of leaves, finding things that are close
2232 * to the block in 'slot', and triggering ra on them.
2234 static void reada_for_search(struct btrfs_root
*root
,
2235 struct btrfs_path
*path
,
2236 int level
, int slot
, u64 objectid
)
2238 struct extent_buffer
*node
;
2239 struct btrfs_disk_key disk_key
;
2245 int direction
= path
->reada
;
2246 struct extent_buffer
*eb
;
2254 if (!path
->nodes
[level
])
2257 node
= path
->nodes
[level
];
2259 search
= btrfs_node_blockptr(node
, slot
);
2260 blocksize
= root
->nodesize
;
2261 eb
= btrfs_find_tree_block(root
->fs_info
, search
);
2263 free_extent_buffer(eb
);
2269 nritems
= btrfs_header_nritems(node
);
2273 if (direction
< 0) {
2277 } else if (direction
> 0) {
2282 if (path
->reada
< 0 && objectid
) {
2283 btrfs_node_key(node
, &disk_key
, nr
);
2284 if (btrfs_disk_key_objectid(&disk_key
) != objectid
)
2287 search
= btrfs_node_blockptr(node
, nr
);
2288 if ((search
<= target
&& target
- search
<= 65536) ||
2289 (search
> target
&& search
- target
<= 65536)) {
2290 gen
= btrfs_node_ptr_generation(node
, nr
);
2291 readahead_tree_block(root
, search
);
2295 if ((nread
> 65536 || nscan
> 32))
2300 static noinline
void reada_for_balance(struct btrfs_root
*root
,
2301 struct btrfs_path
*path
, int level
)
2305 struct extent_buffer
*parent
;
2306 struct extent_buffer
*eb
;
2311 parent
= path
->nodes
[level
+ 1];
2315 nritems
= btrfs_header_nritems(parent
);
2316 slot
= path
->slots
[level
+ 1];
2319 block1
= btrfs_node_blockptr(parent
, slot
- 1);
2320 gen
= btrfs_node_ptr_generation(parent
, slot
- 1);
2321 eb
= btrfs_find_tree_block(root
->fs_info
, block1
);
2323 * if we get -eagain from btrfs_buffer_uptodate, we
2324 * don't want to return eagain here. That will loop
2327 if (eb
&& btrfs_buffer_uptodate(eb
, gen
, 1) != 0)
2329 free_extent_buffer(eb
);
2331 if (slot
+ 1 < nritems
) {
2332 block2
= btrfs_node_blockptr(parent
, slot
+ 1);
2333 gen
= btrfs_node_ptr_generation(parent
, slot
+ 1);
2334 eb
= btrfs_find_tree_block(root
->fs_info
, block2
);
2335 if (eb
&& btrfs_buffer_uptodate(eb
, gen
, 1) != 0)
2337 free_extent_buffer(eb
);
2341 readahead_tree_block(root
, block1
);
2343 readahead_tree_block(root
, block2
);
2348 * when we walk down the tree, it is usually safe to unlock the higher layers
2349 * in the tree. The exceptions are when our path goes through slot 0, because
2350 * operations on the tree might require changing key pointers higher up in the
2353 * callers might also have set path->keep_locks, which tells this code to keep
2354 * the lock if the path points to the last slot in the block. This is part of
2355 * walking through the tree, and selecting the next slot in the higher block.
2357 * lowest_unlock sets the lowest level in the tree we're allowed to unlock. so
2358 * if lowest_unlock is 1, level 0 won't be unlocked
2360 static noinline
void unlock_up(struct btrfs_path
*path
, int level
,
2361 int lowest_unlock
, int min_write_lock_level
,
2362 int *write_lock_level
)
2365 int skip_level
= level
;
2367 struct extent_buffer
*t
;
2369 for (i
= level
; i
< BTRFS_MAX_LEVEL
; i
++) {
2370 if (!path
->nodes
[i
])
2372 if (!path
->locks
[i
])
2374 if (!no_skips
&& path
->slots
[i
] == 0) {
2378 if (!no_skips
&& path
->keep_locks
) {
2381 nritems
= btrfs_header_nritems(t
);
2382 if (nritems
< 1 || path
->slots
[i
] >= nritems
- 1) {
2387 if (skip_level
< i
&& i
>= lowest_unlock
)
2391 if (i
>= lowest_unlock
&& i
> skip_level
&& path
->locks
[i
]) {
2392 btrfs_tree_unlock_rw(t
, path
->locks
[i
]);
2394 if (write_lock_level
&&
2395 i
> min_write_lock_level
&&
2396 i
<= *write_lock_level
) {
2397 *write_lock_level
= i
- 1;
2404 * This releases any locks held in the path starting at level and
2405 * going all the way up to the root.
2407 * btrfs_search_slot will keep the lock held on higher nodes in a few
2408 * corner cases, such as COW of the block at slot zero in the node. This
2409 * ignores those rules, and it should only be called when there are no
2410 * more updates to be done higher up in the tree.
2412 noinline
void btrfs_unlock_up_safe(struct btrfs_path
*path
, int level
)
2416 if (path
->keep_locks
)
2419 for (i
= level
; i
< BTRFS_MAX_LEVEL
; i
++) {
2420 if (!path
->nodes
[i
])
2422 if (!path
->locks
[i
])
2424 btrfs_tree_unlock_rw(path
->nodes
[i
], path
->locks
[i
]);
2430 * helper function for btrfs_search_slot. The goal is to find a block
2431 * in cache without setting the path to blocking. If we find the block
2432 * we return zero and the path is unchanged.
2434 * If we can't find the block, we set the path blocking and do some
2435 * reada. -EAGAIN is returned and the search must be repeated.
2438 read_block_for_search(struct btrfs_trans_handle
*trans
,
2439 struct btrfs_root
*root
, struct btrfs_path
*p
,
2440 struct extent_buffer
**eb_ret
, int level
, int slot
,
2441 struct btrfs_key
*key
, u64 time_seq
)
2445 struct extent_buffer
*b
= *eb_ret
;
2446 struct extent_buffer
*tmp
;
2449 blocknr
= btrfs_node_blockptr(b
, slot
);
2450 gen
= btrfs_node_ptr_generation(b
, slot
);
2452 tmp
= btrfs_find_tree_block(root
->fs_info
, blocknr
);
2454 /* first we do an atomic uptodate check */
2455 if (btrfs_buffer_uptodate(tmp
, gen
, 1) > 0) {
2460 /* the pages were up to date, but we failed
2461 * the generation number check. Do a full
2462 * read for the generation number that is correct.
2463 * We must do this without dropping locks so
2464 * we can trust our generation number
2466 btrfs_set_path_blocking(p
);
2468 /* now we're allowed to do a blocking uptodate check */
2469 ret
= btrfs_read_buffer(tmp
, gen
);
2474 free_extent_buffer(tmp
);
2475 btrfs_release_path(p
);
2480 * reduce lock contention at high levels
2481 * of the btree by dropping locks before
2482 * we read. Don't release the lock on the current
2483 * level because we need to walk this node to figure
2484 * out which blocks to read.
2486 btrfs_unlock_up_safe(p
, level
+ 1);
2487 btrfs_set_path_blocking(p
);
2489 free_extent_buffer(tmp
);
2491 reada_for_search(root
, p
, level
, slot
, key
->objectid
);
2493 btrfs_release_path(p
);
2496 tmp
= read_tree_block(root
, blocknr
, 0);
2499 * If the read above didn't mark this buffer up to date,
2500 * it will never end up being up to date. Set ret to EIO now
2501 * and give up so that our caller doesn't loop forever
2504 if (!btrfs_buffer_uptodate(tmp
, 0, 0))
2506 free_extent_buffer(tmp
);
2512 * helper function for btrfs_search_slot. This does all of the checks
2513 * for node-level blocks and does any balancing required based on
2516 * If no extra work was required, zero is returned. If we had to
2517 * drop the path, -EAGAIN is returned and btrfs_search_slot must
2521 setup_nodes_for_search(struct btrfs_trans_handle
*trans
,
2522 struct btrfs_root
*root
, struct btrfs_path
*p
,
2523 struct extent_buffer
*b
, int level
, int ins_len
,
2524 int *write_lock_level
)
2527 if ((p
->search_for_split
|| ins_len
> 0) && btrfs_header_nritems(b
) >=
2528 BTRFS_NODEPTRS_PER_BLOCK(root
) - 3) {
2531 if (*write_lock_level
< level
+ 1) {
2532 *write_lock_level
= level
+ 1;
2533 btrfs_release_path(p
);
2537 btrfs_set_path_blocking(p
);
2538 reada_for_balance(root
, p
, level
);
2539 sret
= split_node(trans
, root
, p
, level
);
2540 btrfs_clear_path_blocking(p
, NULL
, 0);
2547 b
= p
->nodes
[level
];
2548 } else if (ins_len
< 0 && btrfs_header_nritems(b
) <
2549 BTRFS_NODEPTRS_PER_BLOCK(root
) / 2) {
2552 if (*write_lock_level
< level
+ 1) {
2553 *write_lock_level
= level
+ 1;
2554 btrfs_release_path(p
);
2558 btrfs_set_path_blocking(p
);
2559 reada_for_balance(root
, p
, level
);
2560 sret
= balance_level(trans
, root
, p
, level
);
2561 btrfs_clear_path_blocking(p
, NULL
, 0);
2567 b
= p
->nodes
[level
];
2569 btrfs_release_path(p
);
2572 BUG_ON(btrfs_header_nritems(b
) == 1);
2582 static void key_search_validate(struct extent_buffer
*b
,
2583 struct btrfs_key
*key
,
2586 #ifdef CONFIG_BTRFS_ASSERT
2587 struct btrfs_disk_key disk_key
;
2589 btrfs_cpu_key_to_disk(&disk_key
, key
);
2592 ASSERT(!memcmp_extent_buffer(b
, &disk_key
,
2593 offsetof(struct btrfs_leaf
, items
[0].key
),
2596 ASSERT(!memcmp_extent_buffer(b
, &disk_key
,
2597 offsetof(struct btrfs_node
, ptrs
[0].key
),
2602 static int key_search(struct extent_buffer
*b
, struct btrfs_key
*key
,
2603 int level
, int *prev_cmp
, int *slot
)
2605 if (*prev_cmp
!= 0) {
2606 *prev_cmp
= bin_search(b
, key
, level
, slot
);
2610 key_search_validate(b
, key
, level
);
2616 int btrfs_find_item(struct btrfs_root
*fs_root
, struct btrfs_path
*path
,
2617 u64 iobjectid
, u64 ioff
, u8 key_type
,
2618 struct btrfs_key
*found_key
)
2621 struct btrfs_key key
;
2622 struct extent_buffer
*eb
;
2627 key
.type
= key_type
;
2628 key
.objectid
= iobjectid
;
2631 ret
= btrfs_search_slot(NULL
, fs_root
, &key
, path
, 0, 0);
2635 eb
= path
->nodes
[0];
2636 if (ret
&& path
->slots
[0] >= btrfs_header_nritems(eb
)) {
2637 ret
= btrfs_next_leaf(fs_root
, path
);
2640 eb
= path
->nodes
[0];
2643 btrfs_item_key_to_cpu(eb
, found_key
, path
->slots
[0]);
2644 if (found_key
->type
!= key
.type
||
2645 found_key
->objectid
!= key
.objectid
)
2652 * look for key in the tree. path is filled in with nodes along the way
2653 * if key is found, we return zero and you can find the item in the leaf
2654 * level of the path (level 0)
2656 * If the key isn't found, the path points to the slot where it should
2657 * be inserted, and 1 is returned. If there are other errors during the
2658 * search a negative error number is returned.
2660 * if ins_len > 0, nodes and leaves will be split as we walk down the
2661 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
2664 int btrfs_search_slot(struct btrfs_trans_handle
*trans
, struct btrfs_root
2665 *root
, struct btrfs_key
*key
, struct btrfs_path
*p
, int
2668 struct extent_buffer
*b
;
2673 int lowest_unlock
= 1;
2675 /* everything at write_lock_level or lower must be write locked */
2676 int write_lock_level
= 0;
2677 u8 lowest_level
= 0;
2678 int min_write_lock_level
;
2681 lowest_level
= p
->lowest_level
;
2682 WARN_ON(lowest_level
&& ins_len
> 0);
2683 WARN_ON(p
->nodes
[0] != NULL
);
2684 BUG_ON(!cow
&& ins_len
);
2689 /* when we are removing items, we might have to go up to level
2690 * two as we update tree pointers Make sure we keep write
2691 * for those levels as well
2693 write_lock_level
= 2;
2694 } else if (ins_len
> 0) {
2696 * for inserting items, make sure we have a write lock on
2697 * level 1 so we can update keys
2699 write_lock_level
= 1;
2703 write_lock_level
= -1;
2705 if (cow
&& (p
->keep_locks
|| p
->lowest_level
))
2706 write_lock_level
= BTRFS_MAX_LEVEL
;
2708 min_write_lock_level
= write_lock_level
;
2713 * we try very hard to do read locks on the root
2715 root_lock
= BTRFS_READ_LOCK
;
2717 if (p
->search_commit_root
) {
2719 * the commit roots are read only
2720 * so we always do read locks
2722 if (p
->need_commit_sem
)
2723 down_read(&root
->fs_info
->commit_root_sem
);
2724 b
= root
->commit_root
;
2725 extent_buffer_get(b
);
2726 level
= btrfs_header_level(b
);
2727 if (p
->need_commit_sem
)
2728 up_read(&root
->fs_info
->commit_root_sem
);
2729 if (!p
->skip_locking
)
2730 btrfs_tree_read_lock(b
);
2732 if (p
->skip_locking
) {
2733 b
= btrfs_root_node(root
);
2734 level
= btrfs_header_level(b
);
2736 /* we don't know the level of the root node
2737 * until we actually have it read locked
2739 b
= btrfs_read_lock_root_node(root
);
2740 level
= btrfs_header_level(b
);
2741 if (level
<= write_lock_level
) {
2742 /* whoops, must trade for write lock */
2743 btrfs_tree_read_unlock(b
);
2744 free_extent_buffer(b
);
2745 b
= btrfs_lock_root_node(root
);
2746 root_lock
= BTRFS_WRITE_LOCK
;
2748 /* the level might have changed, check again */
2749 level
= btrfs_header_level(b
);
2753 p
->nodes
[level
] = b
;
2754 if (!p
->skip_locking
)
2755 p
->locks
[level
] = root_lock
;
2758 level
= btrfs_header_level(b
);
2761 * setup the path here so we can release it under lock
2762 * contention with the cow code
2766 * if we don't really need to cow this block
2767 * then we don't want to set the path blocking,
2768 * so we test it here
2770 if (!should_cow_block(trans
, root
, b
))
2774 * must have write locks on this node and the
2777 if (level
> write_lock_level
||
2778 (level
+ 1 > write_lock_level
&&
2779 level
+ 1 < BTRFS_MAX_LEVEL
&&
2780 p
->nodes
[level
+ 1])) {
2781 write_lock_level
= level
+ 1;
2782 btrfs_release_path(p
);
2786 btrfs_set_path_blocking(p
);
2787 err
= btrfs_cow_block(trans
, root
, b
,
2788 p
->nodes
[level
+ 1],
2789 p
->slots
[level
+ 1], &b
);
2796 p
->nodes
[level
] = b
;
2797 btrfs_clear_path_blocking(p
, NULL
, 0);
2800 * we have a lock on b and as long as we aren't changing
2801 * the tree, there is no way to for the items in b to change.
2802 * It is safe to drop the lock on our parent before we
2803 * go through the expensive btree search on b.
2805 * If we're inserting or deleting (ins_len != 0), then we might
2806 * be changing slot zero, which may require changing the parent.
2807 * So, we can't drop the lock until after we know which slot
2808 * we're operating on.
2810 if (!ins_len
&& !p
->keep_locks
) {
2813 if (u
< BTRFS_MAX_LEVEL
&& p
->locks
[u
]) {
2814 btrfs_tree_unlock_rw(p
->nodes
[u
], p
->locks
[u
]);
2819 ret
= key_search(b
, key
, level
, &prev_cmp
, &slot
);
2823 if (ret
&& slot
> 0) {
2827 p
->slots
[level
] = slot
;
2828 err
= setup_nodes_for_search(trans
, root
, p
, b
, level
,
2829 ins_len
, &write_lock_level
);
2836 b
= p
->nodes
[level
];
2837 slot
= p
->slots
[level
];
2840 * slot 0 is special, if we change the key
2841 * we have to update the parent pointer
2842 * which means we must have a write lock
2845 if (slot
== 0 && ins_len
&&
2846 write_lock_level
< level
+ 1) {
2847 write_lock_level
= level
+ 1;
2848 btrfs_release_path(p
);
2852 unlock_up(p
, level
, lowest_unlock
,
2853 min_write_lock_level
, &write_lock_level
);
2855 if (level
== lowest_level
) {
2861 err
= read_block_for_search(trans
, root
, p
,
2862 &b
, level
, slot
, key
, 0);
2870 if (!p
->skip_locking
) {
2871 level
= btrfs_header_level(b
);
2872 if (level
<= write_lock_level
) {
2873 err
= btrfs_try_tree_write_lock(b
);
2875 btrfs_set_path_blocking(p
);
2877 btrfs_clear_path_blocking(p
, b
,
2880 p
->locks
[level
] = BTRFS_WRITE_LOCK
;
2882 err
= btrfs_tree_read_lock_atomic(b
);
2884 btrfs_set_path_blocking(p
);
2885 btrfs_tree_read_lock(b
);
2886 btrfs_clear_path_blocking(p
, b
,
2889 p
->locks
[level
] = BTRFS_READ_LOCK
;
2891 p
->nodes
[level
] = b
;
2894 p
->slots
[level
] = slot
;
2896 btrfs_leaf_free_space(root
, b
) < ins_len
) {
2897 if (write_lock_level
< 1) {
2898 write_lock_level
= 1;
2899 btrfs_release_path(p
);
2903 btrfs_set_path_blocking(p
);
2904 err
= split_leaf(trans
, root
, key
,
2905 p
, ins_len
, ret
== 0);
2906 btrfs_clear_path_blocking(p
, NULL
, 0);
2914 if (!p
->search_for_split
)
2915 unlock_up(p
, level
, lowest_unlock
,
2916 min_write_lock_level
, &write_lock_level
);
2923 * we don't really know what they plan on doing with the path
2924 * from here on, so for now just mark it as blocking
2926 if (!p
->leave_spinning
)
2927 btrfs_set_path_blocking(p
);
2928 if (ret
< 0 && !p
->skip_release_on_error
)
2929 btrfs_release_path(p
);
2934 * Like btrfs_search_slot, this looks for a key in the given tree. It uses the
2935 * current state of the tree together with the operations recorded in the tree
2936 * modification log to search for the key in a previous version of this tree, as
2937 * denoted by the time_seq parameter.
2939 * Naturally, there is no support for insert, delete or cow operations.
2941 * The resulting path and return value will be set up as if we called
2942 * btrfs_search_slot at that point in time with ins_len and cow both set to 0.
2944 int btrfs_search_old_slot(struct btrfs_root
*root
, struct btrfs_key
*key
,
2945 struct btrfs_path
*p
, u64 time_seq
)
2947 struct extent_buffer
*b
;
2952 int lowest_unlock
= 1;
2953 u8 lowest_level
= 0;
2956 lowest_level
= p
->lowest_level
;
2957 WARN_ON(p
->nodes
[0] != NULL
);
2959 if (p
->search_commit_root
) {
2961 return btrfs_search_slot(NULL
, root
, key
, p
, 0, 0);
2965 b
= get_old_root(root
, time_seq
);
2966 level
= btrfs_header_level(b
);
2967 p
->locks
[level
] = BTRFS_READ_LOCK
;
2970 level
= btrfs_header_level(b
);
2971 p
->nodes
[level
] = b
;
2972 btrfs_clear_path_blocking(p
, NULL
, 0);
2975 * we have a lock on b and as long as we aren't changing
2976 * the tree, there is no way to for the items in b to change.
2977 * It is safe to drop the lock on our parent before we
2978 * go through the expensive btree search on b.
2980 btrfs_unlock_up_safe(p
, level
+ 1);
2983 * Since we can unwind eb's we want to do a real search every
2987 ret
= key_search(b
, key
, level
, &prev_cmp
, &slot
);
2991 if (ret
&& slot
> 0) {
2995 p
->slots
[level
] = slot
;
2996 unlock_up(p
, level
, lowest_unlock
, 0, NULL
);
2998 if (level
== lowest_level
) {
3004 err
= read_block_for_search(NULL
, root
, p
, &b
, level
,
3005 slot
, key
, time_seq
);
3013 level
= btrfs_header_level(b
);
3014 err
= btrfs_tree_read_lock_atomic(b
);
3016 btrfs_set_path_blocking(p
);
3017 btrfs_tree_read_lock(b
);
3018 btrfs_clear_path_blocking(p
, b
,
3021 b
= tree_mod_log_rewind(root
->fs_info
, p
, b
, time_seq
);
3026 p
->locks
[level
] = BTRFS_READ_LOCK
;
3027 p
->nodes
[level
] = b
;
3029 p
->slots
[level
] = slot
;
3030 unlock_up(p
, level
, lowest_unlock
, 0, NULL
);
3036 if (!p
->leave_spinning
)
3037 btrfs_set_path_blocking(p
);
3039 btrfs_release_path(p
);
3045 * helper to use instead of search slot if no exact match is needed but
3046 * instead the next or previous item should be returned.
3047 * When find_higher is true, the next higher item is returned, the next lower
3049 * When return_any and find_higher are both true, and no higher item is found,
3050 * return the next lower instead.
3051 * When return_any is true and find_higher is false, and no lower item is found,
3052 * return the next higher instead.
3053 * It returns 0 if any item is found, 1 if none is found (tree empty), and
3056 int btrfs_search_slot_for_read(struct btrfs_root
*root
,
3057 struct btrfs_key
*key
, struct btrfs_path
*p
,
3058 int find_higher
, int return_any
)
3061 struct extent_buffer
*leaf
;
3064 ret
= btrfs_search_slot(NULL
, root
, key
, p
, 0, 0);
3068 * a return value of 1 means the path is at the position where the
3069 * item should be inserted. Normally this is the next bigger item,
3070 * but in case the previous item is the last in a leaf, path points
3071 * to the first free slot in the previous leaf, i.e. at an invalid
3077 if (p
->slots
[0] >= btrfs_header_nritems(leaf
)) {
3078 ret
= btrfs_next_leaf(root
, p
);
3084 * no higher item found, return the next
3089 btrfs_release_path(p
);
3093 if (p
->slots
[0] == 0) {
3094 ret
= btrfs_prev_leaf(root
, p
);
3099 if (p
->slots
[0] == btrfs_header_nritems(leaf
))
3106 * no lower item found, return the next
3111 btrfs_release_path(p
);
3121 * adjust the pointers going up the tree, starting at level
3122 * making sure the right key of each node is points to 'key'.
3123 * This is used after shifting pointers to the left, so it stops
3124 * fixing up pointers when a given leaf/node is not in slot 0 of the
3128 static void fixup_low_keys(struct btrfs_fs_info
*fs_info
,
3129 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(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_fs_info
*fs_info
,
3155 struct btrfs_path
*path
,
3156 struct btrfs_key
*new_key
)
3158 struct btrfs_disk_key disk_key
;
3159 struct extent_buffer
*eb
;
3162 eb
= path
->nodes
[0];
3163 slot
= path
->slots
[0];
3165 btrfs_item_key(eb
, &disk_key
, slot
- 1);
3166 BUG_ON(comp_keys(&disk_key
, new_key
) >= 0);
3168 if (slot
< btrfs_header_nritems(eb
) - 1) {
3169 btrfs_item_key(eb
, &disk_key
, slot
+ 1);
3170 BUG_ON(comp_keys(&disk_key
, new_key
) <= 0);
3173 btrfs_cpu_key_to_disk(&disk_key
, new_key
);
3174 btrfs_set_item_key(eb
, &disk_key
, slot
);
3175 btrfs_mark_buffer_dirty(eb
);
3177 fixup_low_keys(fs_info
, path
, &disk_key
, 1);
3181 * try to push data from one node into the next node left in the
3184 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
3185 * error, and > 0 if there was no room in the left hand block.
3187 static int push_node_left(struct btrfs_trans_handle
*trans
,
3188 struct btrfs_root
*root
, struct extent_buffer
*dst
,
3189 struct extent_buffer
*src
, int empty
)
3196 src_nritems
= btrfs_header_nritems(src
);
3197 dst_nritems
= btrfs_header_nritems(dst
);
3198 push_items
= BTRFS_NODEPTRS_PER_BLOCK(root
) - dst_nritems
;
3199 WARN_ON(btrfs_header_generation(src
) != trans
->transid
);
3200 WARN_ON(btrfs_header_generation(dst
) != trans
->transid
);
3202 if (!empty
&& src_nritems
<= 8)
3205 if (push_items
<= 0)
3209 push_items
= min(src_nritems
, push_items
);
3210 if (push_items
< src_nritems
) {
3211 /* leave at least 8 pointers in the node if
3212 * we aren't going to empty it
3214 if (src_nritems
- push_items
< 8) {
3215 if (push_items
<= 8)
3221 push_items
= min(src_nritems
- 8, push_items
);
3223 ret
= tree_mod_log_eb_copy(root
->fs_info
, dst
, src
, dst_nritems
, 0,
3226 btrfs_abort_transaction(trans
, root
, ret
);
3229 copy_extent_buffer(dst
, src
,
3230 btrfs_node_key_ptr_offset(dst_nritems
),
3231 btrfs_node_key_ptr_offset(0),
3232 push_items
* sizeof(struct btrfs_key_ptr
));
3234 if (push_items
< src_nritems
) {
3236 * don't call tree_mod_log_eb_move here, key removal was already
3237 * fully logged by tree_mod_log_eb_copy above.
3239 memmove_extent_buffer(src
, btrfs_node_key_ptr_offset(0),
3240 btrfs_node_key_ptr_offset(push_items
),
3241 (src_nritems
- push_items
) *
3242 sizeof(struct btrfs_key_ptr
));
3244 btrfs_set_header_nritems(src
, src_nritems
- push_items
);
3245 btrfs_set_header_nritems(dst
, dst_nritems
+ push_items
);
3246 btrfs_mark_buffer_dirty(src
);
3247 btrfs_mark_buffer_dirty(dst
);
3253 * try to push data from one node into the next node right in the
3256 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
3257 * error, and > 0 if there was no room in the right hand block.
3259 * this will only push up to 1/2 the contents of the left node over
3261 static int balance_node_right(struct btrfs_trans_handle
*trans
,
3262 struct btrfs_root
*root
,
3263 struct extent_buffer
*dst
,
3264 struct extent_buffer
*src
)
3272 WARN_ON(btrfs_header_generation(src
) != trans
->transid
);
3273 WARN_ON(btrfs_header_generation(dst
) != trans
->transid
);
3275 src_nritems
= btrfs_header_nritems(src
);
3276 dst_nritems
= btrfs_header_nritems(dst
);
3277 push_items
= BTRFS_NODEPTRS_PER_BLOCK(root
) - dst_nritems
;
3278 if (push_items
<= 0)
3281 if (src_nritems
< 4)
3284 max_push
= src_nritems
/ 2 + 1;
3285 /* don't try to empty the node */
3286 if (max_push
>= src_nritems
)
3289 if (max_push
< push_items
)
3290 push_items
= max_push
;
3292 tree_mod_log_eb_move(root
->fs_info
, dst
, push_items
, 0, dst_nritems
);
3293 memmove_extent_buffer(dst
, btrfs_node_key_ptr_offset(push_items
),
3294 btrfs_node_key_ptr_offset(0),
3296 sizeof(struct btrfs_key_ptr
));
3298 ret
= tree_mod_log_eb_copy(root
->fs_info
, dst
, src
, 0,
3299 src_nritems
- push_items
, push_items
);
3301 btrfs_abort_transaction(trans
, root
, ret
);
3304 copy_extent_buffer(dst
, src
,
3305 btrfs_node_key_ptr_offset(0),
3306 btrfs_node_key_ptr_offset(src_nritems
- push_items
),
3307 push_items
* sizeof(struct btrfs_key_ptr
));
3309 btrfs_set_header_nritems(src
, src_nritems
- push_items
);
3310 btrfs_set_header_nritems(dst
, dst_nritems
+ push_items
);
3312 btrfs_mark_buffer_dirty(src
);
3313 btrfs_mark_buffer_dirty(dst
);
3319 * helper function to insert a new root level in the tree.
3320 * A new node is allocated, and a single item is inserted to
3321 * point to the existing root
3323 * returns zero on success or < 0 on failure.
3325 static noinline
int insert_new_root(struct btrfs_trans_handle
*trans
,
3326 struct btrfs_root
*root
,
3327 struct btrfs_path
*path
, int level
)
3330 struct extent_buffer
*lower
;
3331 struct extent_buffer
*c
;
3332 struct extent_buffer
*old
;
3333 struct btrfs_disk_key lower_key
;
3335 BUG_ON(path
->nodes
[level
]);
3336 BUG_ON(path
->nodes
[level
-1] != root
->node
);
3338 lower
= path
->nodes
[level
-1];
3340 btrfs_item_key(lower
, &lower_key
, 0);
3342 btrfs_node_key(lower
, &lower_key
, 0);
3344 c
= btrfs_alloc_tree_block(trans
, root
, 0, root
->root_key
.objectid
,
3345 &lower_key
, level
, root
->node
->start
, 0);
3349 root_add_used(root
, root
->nodesize
);
3351 memset_extent_buffer(c
, 0, 0, sizeof(struct btrfs_header
));
3352 btrfs_set_header_nritems(c
, 1);
3353 btrfs_set_header_level(c
, level
);
3354 btrfs_set_header_bytenr(c
, c
->start
);
3355 btrfs_set_header_generation(c
, trans
->transid
);
3356 btrfs_set_header_backref_rev(c
, BTRFS_MIXED_BACKREF_REV
);
3357 btrfs_set_header_owner(c
, root
->root_key
.objectid
);
3359 write_extent_buffer(c
, root
->fs_info
->fsid
, btrfs_header_fsid(),
3362 write_extent_buffer(c
, root
->fs_info
->chunk_tree_uuid
,
3363 btrfs_header_chunk_tree_uuid(c
), BTRFS_UUID_SIZE
);
3365 btrfs_set_node_key(c
, &lower_key
, 0);
3366 btrfs_set_node_blockptr(c
, 0, lower
->start
);
3367 lower_gen
= btrfs_header_generation(lower
);
3368 WARN_ON(lower_gen
!= trans
->transid
);
3370 btrfs_set_node_ptr_generation(c
, 0, lower_gen
);
3372 btrfs_mark_buffer_dirty(c
);
3375 tree_mod_log_set_root_pointer(root
, c
, 0);
3376 rcu_assign_pointer(root
->node
, c
);
3378 /* the super has an extra ref to root->node */
3379 free_extent_buffer(old
);
3381 add_root_to_dirty_list(root
);
3382 extent_buffer_get(c
);
3383 path
->nodes
[level
] = c
;
3384 path
->locks
[level
] = BTRFS_WRITE_LOCK_BLOCKING
;
3385 path
->slots
[level
] = 0;
3390 * worker function to insert a single pointer in a node.
3391 * the node should have enough room for the pointer already
3393 * slot and level indicate where you want the key to go, and
3394 * blocknr is the block the key points to.
3396 static void insert_ptr(struct btrfs_trans_handle
*trans
,
3397 struct btrfs_root
*root
, struct btrfs_path
*path
,
3398 struct btrfs_disk_key
*key
, u64 bytenr
,
3399 int slot
, int level
)
3401 struct extent_buffer
*lower
;
3405 BUG_ON(!path
->nodes
[level
]);
3406 btrfs_assert_tree_locked(path
->nodes
[level
]);
3407 lower
= path
->nodes
[level
];
3408 nritems
= btrfs_header_nritems(lower
);
3409 BUG_ON(slot
> nritems
);
3410 BUG_ON(nritems
== BTRFS_NODEPTRS_PER_BLOCK(root
));
3411 if (slot
!= nritems
) {
3413 tree_mod_log_eb_move(root
->fs_info
, lower
, slot
+ 1,
3414 slot
, nritems
- slot
);
3415 memmove_extent_buffer(lower
,
3416 btrfs_node_key_ptr_offset(slot
+ 1),
3417 btrfs_node_key_ptr_offset(slot
),
3418 (nritems
- slot
) * sizeof(struct btrfs_key_ptr
));
3421 ret
= tree_mod_log_insert_key(root
->fs_info
, lower
, slot
,
3422 MOD_LOG_KEY_ADD
, GFP_NOFS
);
3425 btrfs_set_node_key(lower
, key
, slot
);
3426 btrfs_set_node_blockptr(lower
, slot
, bytenr
);
3427 WARN_ON(trans
->transid
== 0);
3428 btrfs_set_node_ptr_generation(lower
, slot
, trans
->transid
);
3429 btrfs_set_header_nritems(lower
, nritems
+ 1);
3430 btrfs_mark_buffer_dirty(lower
);
3434 * split the node at the specified level in path in two.
3435 * The path is corrected to point to the appropriate node after the split
3437 * Before splitting this tries to make some room in the node by pushing
3438 * left and right, if either one works, it returns right away.
3440 * returns 0 on success and < 0 on failure
3442 static noinline
int split_node(struct btrfs_trans_handle
*trans
,
3443 struct btrfs_root
*root
,
3444 struct btrfs_path
*path
, int level
)
3446 struct extent_buffer
*c
;
3447 struct extent_buffer
*split
;
3448 struct btrfs_disk_key disk_key
;
3453 c
= path
->nodes
[level
];
3454 WARN_ON(btrfs_header_generation(c
) != trans
->transid
);
3455 if (c
== root
->node
) {
3457 * trying to split the root, lets make a new one
3459 * tree mod log: We don't log_removal old root in
3460 * insert_new_root, because that root buffer will be kept as a
3461 * normal node. We are going to log removal of half of the
3462 * elements below with tree_mod_log_eb_copy. We're holding a
3463 * tree lock on the buffer, which is why we cannot race with
3464 * other tree_mod_log users.
3466 ret
= insert_new_root(trans
, root
, path
, level
+ 1);
3470 ret
= push_nodes_for_insert(trans
, root
, path
, level
);
3471 c
= path
->nodes
[level
];
3472 if (!ret
&& btrfs_header_nritems(c
) <
3473 BTRFS_NODEPTRS_PER_BLOCK(root
) - 3)
3479 c_nritems
= btrfs_header_nritems(c
);
3480 mid
= (c_nritems
+ 1) / 2;
3481 btrfs_node_key(c
, &disk_key
, mid
);
3483 split
= btrfs_alloc_tree_block(trans
, root
, 0, root
->root_key
.objectid
,
3484 &disk_key
, level
, c
->start
, 0);
3486 return PTR_ERR(split
);
3488 root_add_used(root
, root
->nodesize
);
3490 memset_extent_buffer(split
, 0, 0, sizeof(struct btrfs_header
));
3491 btrfs_set_header_level(split
, btrfs_header_level(c
));
3492 btrfs_set_header_bytenr(split
, split
->start
);
3493 btrfs_set_header_generation(split
, trans
->transid
);
3494 btrfs_set_header_backref_rev(split
, BTRFS_MIXED_BACKREF_REV
);
3495 btrfs_set_header_owner(split
, root
->root_key
.objectid
);
3496 write_extent_buffer(split
, root
->fs_info
->fsid
,
3497 btrfs_header_fsid(), BTRFS_FSID_SIZE
);
3498 write_extent_buffer(split
, root
->fs_info
->chunk_tree_uuid
,
3499 btrfs_header_chunk_tree_uuid(split
),
3502 ret
= tree_mod_log_eb_copy(root
->fs_info
, split
, c
, 0,
3503 mid
, c_nritems
- mid
);
3505 btrfs_abort_transaction(trans
, root
, ret
);
3508 copy_extent_buffer(split
, c
,
3509 btrfs_node_key_ptr_offset(0),
3510 btrfs_node_key_ptr_offset(mid
),
3511 (c_nritems
- mid
) * sizeof(struct btrfs_key_ptr
));
3512 btrfs_set_header_nritems(split
, c_nritems
- mid
);
3513 btrfs_set_header_nritems(c
, mid
);
3516 btrfs_mark_buffer_dirty(c
);
3517 btrfs_mark_buffer_dirty(split
);
3519 insert_ptr(trans
, root
, path
, &disk_key
, split
->start
,
3520 path
->slots
[level
+ 1] + 1, level
+ 1);
3522 if (path
->slots
[level
] >= mid
) {
3523 path
->slots
[level
] -= mid
;
3524 btrfs_tree_unlock(c
);
3525 free_extent_buffer(c
);
3526 path
->nodes
[level
] = split
;
3527 path
->slots
[level
+ 1] += 1;
3529 btrfs_tree_unlock(split
);
3530 free_extent_buffer(split
);
3536 * how many bytes are required to store the items in a leaf. start
3537 * and nr indicate which items in the leaf to check. This totals up the
3538 * space used both by the item structs and the item data
3540 static int leaf_space_used(struct extent_buffer
*l
, int start
, int nr
)
3542 struct btrfs_item
*start_item
;
3543 struct btrfs_item
*end_item
;
3544 struct btrfs_map_token token
;
3546 int nritems
= btrfs_header_nritems(l
);
3547 int end
= min(nritems
, start
+ nr
) - 1;
3551 btrfs_init_map_token(&token
);
3552 start_item
= btrfs_item_nr(start
);
3553 end_item
= btrfs_item_nr(end
);
3554 data_len
= btrfs_token_item_offset(l
, start_item
, &token
) +
3555 btrfs_token_item_size(l
, start_item
, &token
);
3556 data_len
= data_len
- btrfs_token_item_offset(l
, end_item
, &token
);
3557 data_len
+= sizeof(struct btrfs_item
) * nr
;
3558 WARN_ON(data_len
< 0);
3563 * The space between the end of the leaf items and
3564 * the start of the leaf data. IOW, how much room
3565 * the leaf has left for both items and data
3567 noinline
int btrfs_leaf_free_space(struct btrfs_root
*root
,
3568 struct extent_buffer
*leaf
)
3570 int nritems
= btrfs_header_nritems(leaf
);
3572 ret
= BTRFS_LEAF_DATA_SIZE(root
) - leaf_space_used(leaf
, 0, nritems
);
3574 btrfs_crit(root
->fs_info
,
3575 "leaf free space ret %d, leaf data size %lu, used %d nritems %d",
3576 ret
, (unsigned long) BTRFS_LEAF_DATA_SIZE(root
),
3577 leaf_space_used(leaf
, 0, nritems
), nritems
);
3583 * min slot controls the lowest index we're willing to push to the
3584 * right. We'll push up to and including min_slot, but no lower
3586 static noinline
int __push_leaf_right(struct btrfs_trans_handle
*trans
,
3587 struct btrfs_root
*root
,
3588 struct btrfs_path
*path
,
3589 int data_size
, int empty
,
3590 struct extent_buffer
*right
,
3591 int free_space
, u32 left_nritems
,
3594 struct extent_buffer
*left
= path
->nodes
[0];
3595 struct extent_buffer
*upper
= path
->nodes
[1];
3596 struct btrfs_map_token token
;
3597 struct btrfs_disk_key disk_key
;
3602 struct btrfs_item
*item
;
3608 btrfs_init_map_token(&token
);
3613 nr
= max_t(u32
, 1, min_slot
);
3615 if (path
->slots
[0] >= left_nritems
)
3616 push_space
+= data_size
;
3618 slot
= path
->slots
[1];
3619 i
= left_nritems
- 1;
3621 item
= btrfs_item_nr(i
);
3623 if (!empty
&& push_items
> 0) {
3624 if (path
->slots
[0] > i
)
3626 if (path
->slots
[0] == i
) {
3627 int space
= btrfs_leaf_free_space(root
, left
);
3628 if (space
+ push_space
* 2 > free_space
)
3633 if (path
->slots
[0] == i
)
3634 push_space
+= data_size
;
3636 this_item_size
= btrfs_item_size(left
, item
);
3637 if (this_item_size
+ sizeof(*item
) + push_space
> free_space
)
3641 push_space
+= this_item_size
+ sizeof(*item
);
3647 if (push_items
== 0)
3650 WARN_ON(!empty
&& push_items
== left_nritems
);
3652 /* push left to right */
3653 right_nritems
= btrfs_header_nritems(right
);
3655 push_space
= btrfs_item_end_nr(left
, left_nritems
- push_items
);
3656 push_space
-= leaf_data_end(root
, left
);
3658 /* make room in the right data area */
3659 data_end
= leaf_data_end(root
, right
);
3660 memmove_extent_buffer(right
,
3661 btrfs_leaf_data(right
) + data_end
- push_space
,
3662 btrfs_leaf_data(right
) + data_end
,
3663 BTRFS_LEAF_DATA_SIZE(root
) - data_end
);
3665 /* copy from the left data area */
3666 copy_extent_buffer(right
, left
, btrfs_leaf_data(right
) +
3667 BTRFS_LEAF_DATA_SIZE(root
) - push_space
,
3668 btrfs_leaf_data(left
) + leaf_data_end(root
, left
),
3671 memmove_extent_buffer(right
, btrfs_item_nr_offset(push_items
),
3672 btrfs_item_nr_offset(0),
3673 right_nritems
* sizeof(struct btrfs_item
));
3675 /* copy the items from left to right */
3676 copy_extent_buffer(right
, left
, btrfs_item_nr_offset(0),
3677 btrfs_item_nr_offset(left_nritems
- push_items
),
3678 push_items
* sizeof(struct btrfs_item
));
3680 /* update the item pointers */
3681 right_nritems
+= push_items
;
3682 btrfs_set_header_nritems(right
, right_nritems
);
3683 push_space
= BTRFS_LEAF_DATA_SIZE(root
);
3684 for (i
= 0; i
< right_nritems
; i
++) {
3685 item
= btrfs_item_nr(i
);
3686 push_space
-= btrfs_token_item_size(right
, item
, &token
);
3687 btrfs_set_token_item_offset(right
, item
, push_space
, &token
);
3690 left_nritems
-= push_items
;
3691 btrfs_set_header_nritems(left
, left_nritems
);
3694 btrfs_mark_buffer_dirty(left
);
3696 clean_tree_block(trans
, root
->fs_info
, left
);
3698 btrfs_mark_buffer_dirty(right
);
3700 btrfs_item_key(right
, &disk_key
, 0);
3701 btrfs_set_node_key(upper
, &disk_key
, slot
+ 1);
3702 btrfs_mark_buffer_dirty(upper
);
3704 /* then fixup the leaf pointer in the path */
3705 if (path
->slots
[0] >= left_nritems
) {
3706 path
->slots
[0] -= left_nritems
;
3707 if (btrfs_header_nritems(path
->nodes
[0]) == 0)
3708 clean_tree_block(trans
, root
->fs_info
, path
->nodes
[0]);
3709 btrfs_tree_unlock(path
->nodes
[0]);
3710 free_extent_buffer(path
->nodes
[0]);
3711 path
->nodes
[0] = right
;
3712 path
->slots
[1] += 1;
3714 btrfs_tree_unlock(right
);
3715 free_extent_buffer(right
);
3720 btrfs_tree_unlock(right
);
3721 free_extent_buffer(right
);
3726 * push some data in the path leaf to the right, trying to free up at
3727 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3729 * returns 1 if the push failed because the other node didn't have enough
3730 * room, 0 if everything worked out and < 0 if there were major errors.
3732 * this will push starting from min_slot to the end of the leaf. It won't
3733 * push any slot lower than min_slot
3735 static int push_leaf_right(struct btrfs_trans_handle
*trans
, struct btrfs_root
3736 *root
, struct btrfs_path
*path
,
3737 int min_data_size
, int data_size
,
3738 int empty
, u32 min_slot
)
3740 struct extent_buffer
*left
= path
->nodes
[0];
3741 struct extent_buffer
*right
;
3742 struct extent_buffer
*upper
;
3748 if (!path
->nodes
[1])
3751 slot
= path
->slots
[1];
3752 upper
= path
->nodes
[1];
3753 if (slot
>= btrfs_header_nritems(upper
) - 1)
3756 btrfs_assert_tree_locked(path
->nodes
[1]);
3758 right
= read_node_slot(root
, upper
, slot
+ 1);
3762 btrfs_tree_lock(right
);
3763 btrfs_set_lock_blocking(right
);
3765 free_space
= btrfs_leaf_free_space(root
, right
);
3766 if (free_space
< data_size
)
3769 /* cow and double check */
3770 ret
= btrfs_cow_block(trans
, root
, right
, upper
,
3775 free_space
= btrfs_leaf_free_space(root
, right
);
3776 if (free_space
< data_size
)
3779 left_nritems
= btrfs_header_nritems(left
);
3780 if (left_nritems
== 0)
3783 if (path
->slots
[0] == left_nritems
&& !empty
) {
3784 /* Key greater than all keys in the leaf, right neighbor has
3785 * enough room for it and we're not emptying our leaf to delete
3786 * it, therefore use right neighbor to insert the new item and
3787 * no need to touch/dirty our left leaft. */
3788 btrfs_tree_unlock(left
);
3789 free_extent_buffer(left
);
3790 path
->nodes
[0] = right
;
3796 return __push_leaf_right(trans
, root
, path
, min_data_size
, empty
,
3797 right
, free_space
, left_nritems
, min_slot
);
3799 btrfs_tree_unlock(right
);
3800 free_extent_buffer(right
);
3805 * push some data in the path leaf to the left, trying to free up at
3806 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3808 * max_slot can put a limit on how far into the leaf we'll push items. The
3809 * item at 'max_slot' won't be touched. Use (u32)-1 to make us do all the
3812 static noinline
int __push_leaf_left(struct btrfs_trans_handle
*trans
,
3813 struct btrfs_root
*root
,
3814 struct btrfs_path
*path
, int data_size
,
3815 int empty
, struct extent_buffer
*left
,
3816 int free_space
, u32 right_nritems
,
3819 struct btrfs_disk_key disk_key
;
3820 struct extent_buffer
*right
= path
->nodes
[0];
3824 struct btrfs_item
*item
;
3825 u32 old_left_nritems
;
3829 u32 old_left_item_size
;
3830 struct btrfs_map_token token
;
3832 btrfs_init_map_token(&token
);
3835 nr
= min(right_nritems
, max_slot
);
3837 nr
= min(right_nritems
- 1, max_slot
);
3839 for (i
= 0; i
< nr
; i
++) {
3840 item
= btrfs_item_nr(i
);
3842 if (!empty
&& push_items
> 0) {
3843 if (path
->slots
[0] < i
)
3845 if (path
->slots
[0] == i
) {
3846 int space
= btrfs_leaf_free_space(root
, right
);
3847 if (space
+ push_space
* 2 > free_space
)
3852 if (path
->slots
[0] == i
)
3853 push_space
+= data_size
;
3855 this_item_size
= btrfs_item_size(right
, item
);
3856 if (this_item_size
+ sizeof(*item
) + push_space
> free_space
)
3860 push_space
+= this_item_size
+ sizeof(*item
);
3863 if (push_items
== 0) {
3867 WARN_ON(!empty
&& push_items
== btrfs_header_nritems(right
));
3869 /* push data from right to left */
3870 copy_extent_buffer(left
, right
,
3871 btrfs_item_nr_offset(btrfs_header_nritems(left
)),
3872 btrfs_item_nr_offset(0),
3873 push_items
* sizeof(struct btrfs_item
));
3875 push_space
= BTRFS_LEAF_DATA_SIZE(root
) -
3876 btrfs_item_offset_nr(right
, push_items
- 1);
3878 copy_extent_buffer(left
, right
, btrfs_leaf_data(left
) +
3879 leaf_data_end(root
, left
) - push_space
,
3880 btrfs_leaf_data(right
) +
3881 btrfs_item_offset_nr(right
, push_items
- 1),
3883 old_left_nritems
= btrfs_header_nritems(left
);
3884 BUG_ON(old_left_nritems
<= 0);
3886 old_left_item_size
= btrfs_item_offset_nr(left
, old_left_nritems
- 1);
3887 for (i
= old_left_nritems
; i
< old_left_nritems
+ push_items
; i
++) {
3890 item
= btrfs_item_nr(i
);
3892 ioff
= btrfs_token_item_offset(left
, item
, &token
);
3893 btrfs_set_token_item_offset(left
, item
,
3894 ioff
- (BTRFS_LEAF_DATA_SIZE(root
) - old_left_item_size
),
3897 btrfs_set_header_nritems(left
, old_left_nritems
+ push_items
);
3899 /* fixup right node */
3900 if (push_items
> right_nritems
)
3901 WARN(1, KERN_CRIT
"push items %d nr %u\n", push_items
,
3904 if (push_items
< right_nritems
) {
3905 push_space
= btrfs_item_offset_nr(right
, push_items
- 1) -
3906 leaf_data_end(root
, right
);
3907 memmove_extent_buffer(right
, btrfs_leaf_data(right
) +
3908 BTRFS_LEAF_DATA_SIZE(root
) - push_space
,
3909 btrfs_leaf_data(right
) +
3910 leaf_data_end(root
, right
), push_space
);
3912 memmove_extent_buffer(right
, btrfs_item_nr_offset(0),
3913 btrfs_item_nr_offset(push_items
),
3914 (btrfs_header_nritems(right
) - push_items
) *
3915 sizeof(struct btrfs_item
));
3917 right_nritems
-= push_items
;
3918 btrfs_set_header_nritems(right
, right_nritems
);
3919 push_space
= BTRFS_LEAF_DATA_SIZE(root
);
3920 for (i
= 0; i
< right_nritems
; i
++) {
3921 item
= btrfs_item_nr(i
);
3923 push_space
= push_space
- btrfs_token_item_size(right
,
3925 btrfs_set_token_item_offset(right
, item
, push_space
, &token
);
3928 btrfs_mark_buffer_dirty(left
);
3930 btrfs_mark_buffer_dirty(right
);
3932 clean_tree_block(trans
, root
->fs_info
, right
);
3934 btrfs_item_key(right
, &disk_key
, 0);
3935 fixup_low_keys(root
->fs_info
, path
, &disk_key
, 1);
3937 /* then fixup the leaf pointer in the path */
3938 if (path
->slots
[0] < push_items
) {
3939 path
->slots
[0] += old_left_nritems
;
3940 btrfs_tree_unlock(path
->nodes
[0]);
3941 free_extent_buffer(path
->nodes
[0]);
3942 path
->nodes
[0] = left
;
3943 path
->slots
[1] -= 1;
3945 btrfs_tree_unlock(left
);
3946 free_extent_buffer(left
);
3947 path
->slots
[0] -= push_items
;
3949 BUG_ON(path
->slots
[0] < 0);
3952 btrfs_tree_unlock(left
);
3953 free_extent_buffer(left
);
3958 * push some data in the path leaf to the left, trying to free up at
3959 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3961 * max_slot can put a limit on how far into the leaf we'll push items. The
3962 * item at 'max_slot' won't be touched. Use (u32)-1 to make us push all the
3965 static int push_leaf_left(struct btrfs_trans_handle
*trans
, struct btrfs_root
3966 *root
, struct btrfs_path
*path
, int min_data_size
,
3967 int data_size
, int empty
, u32 max_slot
)
3969 struct extent_buffer
*right
= path
->nodes
[0];
3970 struct extent_buffer
*left
;
3976 slot
= path
->slots
[1];
3979 if (!path
->nodes
[1])
3982 right_nritems
= btrfs_header_nritems(right
);
3983 if (right_nritems
== 0)
3986 btrfs_assert_tree_locked(path
->nodes
[1]);
3988 left
= read_node_slot(root
, path
->nodes
[1], slot
- 1);
3992 btrfs_tree_lock(left
);
3993 btrfs_set_lock_blocking(left
);
3995 free_space
= btrfs_leaf_free_space(root
, left
);
3996 if (free_space
< data_size
) {
4001 /* cow and double check */
4002 ret
= btrfs_cow_block(trans
, root
, left
,
4003 path
->nodes
[1], slot
- 1, &left
);
4005 /* we hit -ENOSPC, but it isn't fatal here */
4011 free_space
= btrfs_leaf_free_space(root
, left
);
4012 if (free_space
< data_size
) {
4017 return __push_leaf_left(trans
, root
, path
, min_data_size
,
4018 empty
, left
, free_space
, right_nritems
,
4021 btrfs_tree_unlock(left
);
4022 free_extent_buffer(left
);
4027 * split the path's leaf in two, making sure there is at least data_size
4028 * available for the resulting leaf level of the path.
4030 static noinline
void copy_for_split(struct btrfs_trans_handle
*trans
,
4031 struct btrfs_root
*root
,
4032 struct btrfs_path
*path
,
4033 struct extent_buffer
*l
,
4034 struct extent_buffer
*right
,
4035 int slot
, int mid
, int nritems
)
4040 struct btrfs_disk_key disk_key
;
4041 struct btrfs_map_token token
;
4043 btrfs_init_map_token(&token
);
4045 nritems
= nritems
- mid
;
4046 btrfs_set_header_nritems(right
, nritems
);
4047 data_copy_size
= btrfs_item_end_nr(l
, mid
) - leaf_data_end(root
, l
);
4049 copy_extent_buffer(right
, l
, btrfs_item_nr_offset(0),
4050 btrfs_item_nr_offset(mid
),
4051 nritems
* sizeof(struct btrfs_item
));
4053 copy_extent_buffer(right
, l
,
4054 btrfs_leaf_data(right
) + BTRFS_LEAF_DATA_SIZE(root
) -
4055 data_copy_size
, btrfs_leaf_data(l
) +
4056 leaf_data_end(root
, l
), data_copy_size
);
4058 rt_data_off
= BTRFS_LEAF_DATA_SIZE(root
) -
4059 btrfs_item_end_nr(l
, mid
);
4061 for (i
= 0; i
< nritems
; i
++) {
4062 struct btrfs_item
*item
= btrfs_item_nr(i
);
4065 ioff
= btrfs_token_item_offset(right
, item
, &token
);
4066 btrfs_set_token_item_offset(right
, item
,
4067 ioff
+ rt_data_off
, &token
);
4070 btrfs_set_header_nritems(l
, mid
);
4071 btrfs_item_key(right
, &disk_key
, 0);
4072 insert_ptr(trans
, root
, path
, &disk_key
, right
->start
,
4073 path
->slots
[1] + 1, 1);
4075 btrfs_mark_buffer_dirty(right
);
4076 btrfs_mark_buffer_dirty(l
);
4077 BUG_ON(path
->slots
[0] != slot
);
4080 btrfs_tree_unlock(path
->nodes
[0]);
4081 free_extent_buffer(path
->nodes
[0]);
4082 path
->nodes
[0] = right
;
4083 path
->slots
[0] -= mid
;
4084 path
->slots
[1] += 1;
4086 btrfs_tree_unlock(right
);
4087 free_extent_buffer(right
);
4090 BUG_ON(path
->slots
[0] < 0);
4094 * double splits happen when we need to insert a big item in the middle
4095 * of a leaf. A double split can leave us with 3 mostly empty leaves:
4096 * leaf: [ slots 0 - N] [ our target ] [ N + 1 - total in leaf ]
4099 * We avoid this by trying to push the items on either side of our target
4100 * into the adjacent leaves. If all goes well we can avoid the double split
4103 static noinline
int push_for_double_split(struct btrfs_trans_handle
*trans
,
4104 struct btrfs_root
*root
,
4105 struct btrfs_path
*path
,
4112 int space_needed
= data_size
;
4114 slot
= path
->slots
[0];
4115 if (slot
< btrfs_header_nritems(path
->nodes
[0]))
4116 space_needed
-= btrfs_leaf_free_space(root
, path
->nodes
[0]);
4119 * try to push all the items after our slot into the
4122 ret
= push_leaf_right(trans
, root
, path
, 1, space_needed
, 0, slot
);
4129 nritems
= btrfs_header_nritems(path
->nodes
[0]);
4131 * our goal is to get our slot at the start or end of a leaf. If
4132 * we've done so we're done
4134 if (path
->slots
[0] == 0 || path
->slots
[0] == nritems
)
4137 if (btrfs_leaf_free_space(root
, path
->nodes
[0]) >= data_size
)
4140 /* try to push all the items before our slot into the next leaf */
4141 slot
= path
->slots
[0];
4142 ret
= push_leaf_left(trans
, root
, path
, 1, space_needed
, 0, slot
);
4155 * split the path's leaf in two, making sure there is at least data_size
4156 * available for the resulting leaf level of the path.
4158 * returns 0 if all went well and < 0 on failure.
4160 static noinline
int split_leaf(struct btrfs_trans_handle
*trans
,
4161 struct btrfs_root
*root
,
4162 struct btrfs_key
*ins_key
,
4163 struct btrfs_path
*path
, int data_size
,
4166 struct btrfs_disk_key disk_key
;
4167 struct extent_buffer
*l
;
4171 struct extent_buffer
*right
;
4172 struct btrfs_fs_info
*fs_info
= root
->fs_info
;
4176 int num_doubles
= 0;
4177 int tried_avoid_double
= 0;
4180 slot
= path
->slots
[0];
4181 if (extend
&& data_size
+ btrfs_item_size_nr(l
, slot
) +
4182 sizeof(struct btrfs_item
) > BTRFS_LEAF_DATA_SIZE(root
))
4185 /* first try to make some room by pushing left and right */
4186 if (data_size
&& path
->nodes
[1]) {
4187 int space_needed
= data_size
;
4189 if (slot
< btrfs_header_nritems(l
))
4190 space_needed
-= btrfs_leaf_free_space(root
, l
);
4192 wret
= push_leaf_right(trans
, root
, path
, space_needed
,
4193 space_needed
, 0, 0);
4197 wret
= push_leaf_left(trans
, root
, path
, space_needed
,
4198 space_needed
, 0, (u32
)-1);
4204 /* did the pushes work? */
4205 if (btrfs_leaf_free_space(root
, l
) >= data_size
)
4209 if (!path
->nodes
[1]) {
4210 ret
= insert_new_root(trans
, root
, path
, 1);
4217 slot
= path
->slots
[0];
4218 nritems
= btrfs_header_nritems(l
);
4219 mid
= (nritems
+ 1) / 2;
4223 leaf_space_used(l
, mid
, nritems
- mid
) + data_size
>
4224 BTRFS_LEAF_DATA_SIZE(root
)) {
4225 if (slot
>= nritems
) {
4229 if (mid
!= nritems
&&
4230 leaf_space_used(l
, mid
, nritems
- mid
) +
4231 data_size
> BTRFS_LEAF_DATA_SIZE(root
)) {
4232 if (data_size
&& !tried_avoid_double
)
4233 goto push_for_double
;
4239 if (leaf_space_used(l
, 0, mid
) + data_size
>
4240 BTRFS_LEAF_DATA_SIZE(root
)) {
4241 if (!extend
&& data_size
&& slot
== 0) {
4243 } else if ((extend
|| !data_size
) && slot
== 0) {
4247 if (mid
!= nritems
&&
4248 leaf_space_used(l
, mid
, nritems
- mid
) +
4249 data_size
> BTRFS_LEAF_DATA_SIZE(root
)) {
4250 if (data_size
&& !tried_avoid_double
)
4251 goto push_for_double
;
4259 btrfs_cpu_key_to_disk(&disk_key
, ins_key
);
4261 btrfs_item_key(l
, &disk_key
, mid
);
4263 right
= btrfs_alloc_tree_block(trans
, root
, 0, root
->root_key
.objectid
,
4264 &disk_key
, 0, l
->start
, 0);
4266 return PTR_ERR(right
);
4268 root_add_used(root
, root
->nodesize
);
4270 memset_extent_buffer(right
, 0, 0, sizeof(struct btrfs_header
));
4271 btrfs_set_header_bytenr(right
, right
->start
);
4272 btrfs_set_header_generation(right
, trans
->transid
);
4273 btrfs_set_header_backref_rev(right
, BTRFS_MIXED_BACKREF_REV
);
4274 btrfs_set_header_owner(right
, root
->root_key
.objectid
);
4275 btrfs_set_header_level(right
, 0);
4276 write_extent_buffer(right
, fs_info
->fsid
,
4277 btrfs_header_fsid(), BTRFS_FSID_SIZE
);
4279 write_extent_buffer(right
, fs_info
->chunk_tree_uuid
,
4280 btrfs_header_chunk_tree_uuid(right
),
4285 btrfs_set_header_nritems(right
, 0);
4286 insert_ptr(trans
, root
, path
, &disk_key
, right
->start
,
4287 path
->slots
[1] + 1, 1);
4288 btrfs_tree_unlock(path
->nodes
[0]);
4289 free_extent_buffer(path
->nodes
[0]);
4290 path
->nodes
[0] = right
;
4292 path
->slots
[1] += 1;
4294 btrfs_set_header_nritems(right
, 0);
4295 insert_ptr(trans
, root
, path
, &disk_key
, right
->start
,
4297 btrfs_tree_unlock(path
->nodes
[0]);
4298 free_extent_buffer(path
->nodes
[0]);
4299 path
->nodes
[0] = right
;
4301 if (path
->slots
[1] == 0)
4302 fixup_low_keys(fs_info
, path
, &disk_key
, 1);
4304 btrfs_mark_buffer_dirty(right
);
4308 copy_for_split(trans
, root
, path
, l
, right
, slot
, mid
, nritems
);
4311 BUG_ON(num_doubles
!= 0);
4319 push_for_double_split(trans
, root
, path
, data_size
);
4320 tried_avoid_double
= 1;
4321 if (btrfs_leaf_free_space(root
, path
->nodes
[0]) >= data_size
)
4326 static noinline
int setup_leaf_for_split(struct btrfs_trans_handle
*trans
,
4327 struct btrfs_root
*root
,
4328 struct btrfs_path
*path
, int ins_len
)
4330 struct btrfs_key key
;
4331 struct extent_buffer
*leaf
;
4332 struct btrfs_file_extent_item
*fi
;
4337 leaf
= path
->nodes
[0];
4338 btrfs_item_key_to_cpu(leaf
, &key
, path
->slots
[0]);
4340 BUG_ON(key
.type
!= BTRFS_EXTENT_DATA_KEY
&&
4341 key
.type
!= BTRFS_EXTENT_CSUM_KEY
);
4343 if (btrfs_leaf_free_space(root
, leaf
) >= ins_len
)
4346 item_size
= btrfs_item_size_nr(leaf
, path
->slots
[0]);
4347 if (key
.type
== BTRFS_EXTENT_DATA_KEY
) {
4348 fi
= btrfs_item_ptr(leaf
, path
->slots
[0],
4349 struct btrfs_file_extent_item
);
4350 extent_len
= btrfs_file_extent_num_bytes(leaf
, fi
);
4352 btrfs_release_path(path
);
4354 path
->keep_locks
= 1;
4355 path
->search_for_split
= 1;
4356 ret
= btrfs_search_slot(trans
, root
, &key
, path
, 0, 1);
4357 path
->search_for_split
= 0;
4364 leaf
= path
->nodes
[0];
4365 /* if our item isn't there, return now */
4366 if (item_size
!= btrfs_item_size_nr(leaf
, path
->slots
[0]))
4369 /* the leaf has changed, it now has room. return now */
4370 if (btrfs_leaf_free_space(root
, path
->nodes
[0]) >= ins_len
)
4373 if (key
.type
== BTRFS_EXTENT_DATA_KEY
) {
4374 fi
= btrfs_item_ptr(leaf
, path
->slots
[0],
4375 struct btrfs_file_extent_item
);
4376 if (extent_len
!= btrfs_file_extent_num_bytes(leaf
, fi
))
4380 btrfs_set_path_blocking(path
);
4381 ret
= split_leaf(trans
, root
, &key
, path
, ins_len
, 1);
4385 path
->keep_locks
= 0;
4386 btrfs_unlock_up_safe(path
, 1);
4389 path
->keep_locks
= 0;
4393 static noinline
int split_item(struct btrfs_trans_handle
*trans
,
4394 struct btrfs_root
*root
,
4395 struct btrfs_path
*path
,
4396 struct btrfs_key
*new_key
,
4397 unsigned long split_offset
)
4399 struct extent_buffer
*leaf
;
4400 struct btrfs_item
*item
;
4401 struct btrfs_item
*new_item
;
4407 struct btrfs_disk_key disk_key
;
4409 leaf
= path
->nodes
[0];
4410 BUG_ON(btrfs_leaf_free_space(root
, leaf
) < sizeof(struct btrfs_item
));
4412 btrfs_set_path_blocking(path
);
4414 item
= btrfs_item_nr(path
->slots
[0]);
4415 orig_offset
= btrfs_item_offset(leaf
, item
);
4416 item_size
= btrfs_item_size(leaf
, item
);
4418 buf
= kmalloc(item_size
, GFP_NOFS
);
4422 read_extent_buffer(leaf
, buf
, btrfs_item_ptr_offset(leaf
,
4423 path
->slots
[0]), item_size
);
4425 slot
= path
->slots
[0] + 1;
4426 nritems
= btrfs_header_nritems(leaf
);
4427 if (slot
!= nritems
) {
4428 /* shift the items */
4429 memmove_extent_buffer(leaf
, btrfs_item_nr_offset(slot
+ 1),
4430 btrfs_item_nr_offset(slot
),
4431 (nritems
- slot
) * sizeof(struct btrfs_item
));
4434 btrfs_cpu_key_to_disk(&disk_key
, new_key
);
4435 btrfs_set_item_key(leaf
, &disk_key
, slot
);
4437 new_item
= btrfs_item_nr(slot
);
4439 btrfs_set_item_offset(leaf
, new_item
, orig_offset
);
4440 btrfs_set_item_size(leaf
, new_item
, item_size
- split_offset
);
4442 btrfs_set_item_offset(leaf
, item
,
4443 orig_offset
+ item_size
- split_offset
);
4444 btrfs_set_item_size(leaf
, item
, split_offset
);
4446 btrfs_set_header_nritems(leaf
, nritems
+ 1);
4448 /* write the data for the start of the original item */
4449 write_extent_buffer(leaf
, buf
,
4450 btrfs_item_ptr_offset(leaf
, path
->slots
[0]),
4453 /* write the data for the new item */
4454 write_extent_buffer(leaf
, buf
+ split_offset
,
4455 btrfs_item_ptr_offset(leaf
, slot
),
4456 item_size
- split_offset
);
4457 btrfs_mark_buffer_dirty(leaf
);
4459 BUG_ON(btrfs_leaf_free_space(root
, leaf
) < 0);
4465 * This function splits a single item into two items,
4466 * giving 'new_key' to the new item and splitting the
4467 * old one at split_offset (from the start of the item).
4469 * The path may be released by this operation. After
4470 * the split, the path is pointing to the old item. The
4471 * new item is going to be in the same node as the old one.
4473 * Note, the item being split must be smaller enough to live alone on
4474 * a tree block with room for one extra struct btrfs_item
4476 * This allows us to split the item in place, keeping a lock on the
4477 * leaf the entire time.
4479 int btrfs_split_item(struct btrfs_trans_handle
*trans
,
4480 struct btrfs_root
*root
,
4481 struct btrfs_path
*path
,
4482 struct btrfs_key
*new_key
,
4483 unsigned long split_offset
)
4486 ret
= setup_leaf_for_split(trans
, root
, path
,
4487 sizeof(struct btrfs_item
));
4491 ret
= split_item(trans
, root
, path
, new_key
, split_offset
);
4496 * This function duplicate a item, giving 'new_key' to the new item.
4497 * It guarantees both items live in the same tree leaf and the new item
4498 * is contiguous with the original item.
4500 * This allows us to split file extent in place, keeping a lock on the
4501 * leaf the entire time.
4503 int btrfs_duplicate_item(struct btrfs_trans_handle
*trans
,
4504 struct btrfs_root
*root
,
4505 struct btrfs_path
*path
,
4506 struct btrfs_key
*new_key
)
4508 struct extent_buffer
*leaf
;
4512 leaf
= path
->nodes
[0];
4513 item_size
= btrfs_item_size_nr(leaf
, path
->slots
[0]);
4514 ret
= setup_leaf_for_split(trans
, root
, path
,
4515 item_size
+ sizeof(struct btrfs_item
));
4520 setup_items_for_insert(root
, path
, new_key
, &item_size
,
4521 item_size
, item_size
+
4522 sizeof(struct btrfs_item
), 1);
4523 leaf
= path
->nodes
[0];
4524 memcpy_extent_buffer(leaf
,
4525 btrfs_item_ptr_offset(leaf
, path
->slots
[0]),
4526 btrfs_item_ptr_offset(leaf
, path
->slots
[0] - 1),
4532 * make the item pointed to by the path smaller. new_size indicates
4533 * how small to make it, and from_end tells us if we just chop bytes
4534 * off the end of the item or if we shift the item to chop bytes off
4537 void btrfs_truncate_item(struct btrfs_root
*root
, struct btrfs_path
*path
,
4538 u32 new_size
, int from_end
)
4541 struct extent_buffer
*leaf
;
4542 struct btrfs_item
*item
;
4544 unsigned int data_end
;
4545 unsigned int old_data_start
;
4546 unsigned int old_size
;
4547 unsigned int size_diff
;
4549 struct btrfs_map_token token
;
4551 btrfs_init_map_token(&token
);
4553 leaf
= path
->nodes
[0];
4554 slot
= path
->slots
[0];
4556 old_size
= btrfs_item_size_nr(leaf
, slot
);
4557 if (old_size
== new_size
)
4560 nritems
= btrfs_header_nritems(leaf
);
4561 data_end
= leaf_data_end(root
, leaf
);
4563 old_data_start
= btrfs_item_offset_nr(leaf
, slot
);
4565 size_diff
= old_size
- new_size
;
4568 BUG_ON(slot
>= nritems
);
4571 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4573 /* first correct the data pointers */
4574 for (i
= slot
; i
< nritems
; i
++) {
4576 item
= btrfs_item_nr(i
);
4578 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4579 btrfs_set_token_item_offset(leaf
, item
,
4580 ioff
+ size_diff
, &token
);
4583 /* shift the data */
4585 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4586 data_end
+ size_diff
, btrfs_leaf_data(leaf
) +
4587 data_end
, old_data_start
+ new_size
- data_end
);
4589 struct btrfs_disk_key disk_key
;
4592 btrfs_item_key(leaf
, &disk_key
, slot
);
4594 if (btrfs_disk_key_type(&disk_key
) == BTRFS_EXTENT_DATA_KEY
) {
4596 struct btrfs_file_extent_item
*fi
;
4598 fi
= btrfs_item_ptr(leaf
, slot
,
4599 struct btrfs_file_extent_item
);
4600 fi
= (struct btrfs_file_extent_item
*)(
4601 (unsigned long)fi
- size_diff
);
4603 if (btrfs_file_extent_type(leaf
, fi
) ==
4604 BTRFS_FILE_EXTENT_INLINE
) {
4605 ptr
= btrfs_item_ptr_offset(leaf
, slot
);
4606 memmove_extent_buffer(leaf
, ptr
,
4608 BTRFS_FILE_EXTENT_INLINE_DATA_START
);
4612 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4613 data_end
+ size_diff
, btrfs_leaf_data(leaf
) +
4614 data_end
, old_data_start
- data_end
);
4616 offset
= btrfs_disk_key_offset(&disk_key
);
4617 btrfs_set_disk_key_offset(&disk_key
, offset
+ size_diff
);
4618 btrfs_set_item_key(leaf
, &disk_key
, slot
);
4620 fixup_low_keys(root
->fs_info
, path
, &disk_key
, 1);
4623 item
= btrfs_item_nr(slot
);
4624 btrfs_set_item_size(leaf
, item
, new_size
);
4625 btrfs_mark_buffer_dirty(leaf
);
4627 if (btrfs_leaf_free_space(root
, leaf
) < 0) {
4628 btrfs_print_leaf(root
, leaf
);
4634 * make the item pointed to by the path bigger, data_size is the added size.
4636 void btrfs_extend_item(struct btrfs_root
*root
, struct btrfs_path
*path
,
4640 struct extent_buffer
*leaf
;
4641 struct btrfs_item
*item
;
4643 unsigned int data_end
;
4644 unsigned int old_data
;
4645 unsigned int old_size
;
4647 struct btrfs_map_token token
;
4649 btrfs_init_map_token(&token
);
4651 leaf
= path
->nodes
[0];
4653 nritems
= btrfs_header_nritems(leaf
);
4654 data_end
= leaf_data_end(root
, leaf
);
4656 if (btrfs_leaf_free_space(root
, leaf
) < data_size
) {
4657 btrfs_print_leaf(root
, leaf
);
4660 slot
= path
->slots
[0];
4661 old_data
= btrfs_item_end_nr(leaf
, slot
);
4664 if (slot
>= nritems
) {
4665 btrfs_print_leaf(root
, leaf
);
4666 btrfs_crit(root
->fs_info
, "slot %d too large, nritems %d",
4672 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4674 /* first correct the data pointers */
4675 for (i
= slot
; i
< nritems
; i
++) {
4677 item
= btrfs_item_nr(i
);
4679 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4680 btrfs_set_token_item_offset(leaf
, item
,
4681 ioff
- data_size
, &token
);
4684 /* shift the data */
4685 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4686 data_end
- data_size
, btrfs_leaf_data(leaf
) +
4687 data_end
, old_data
- data_end
);
4689 data_end
= old_data
;
4690 old_size
= btrfs_item_size_nr(leaf
, slot
);
4691 item
= btrfs_item_nr(slot
);
4692 btrfs_set_item_size(leaf
, item
, old_size
+ data_size
);
4693 btrfs_mark_buffer_dirty(leaf
);
4695 if (btrfs_leaf_free_space(root
, leaf
) < 0) {
4696 btrfs_print_leaf(root
, leaf
);
4702 * this is a helper for btrfs_insert_empty_items, the main goal here is
4703 * to save stack depth by doing the bulk of the work in a function
4704 * that doesn't call btrfs_search_slot
4706 void setup_items_for_insert(struct btrfs_root
*root
, struct btrfs_path
*path
,
4707 struct btrfs_key
*cpu_key
, u32
*data_size
,
4708 u32 total_data
, u32 total_size
, int nr
)
4710 struct btrfs_item
*item
;
4713 unsigned int data_end
;
4714 struct btrfs_disk_key disk_key
;
4715 struct extent_buffer
*leaf
;
4717 struct btrfs_map_token token
;
4719 if (path
->slots
[0] == 0) {
4720 btrfs_cpu_key_to_disk(&disk_key
, cpu_key
);
4721 fixup_low_keys(root
->fs_info
, path
, &disk_key
, 1);
4723 btrfs_unlock_up_safe(path
, 1);
4725 btrfs_init_map_token(&token
);
4727 leaf
= path
->nodes
[0];
4728 slot
= path
->slots
[0];
4730 nritems
= btrfs_header_nritems(leaf
);
4731 data_end
= leaf_data_end(root
, leaf
);
4733 if (btrfs_leaf_free_space(root
, leaf
) < total_size
) {
4734 btrfs_print_leaf(root
, leaf
);
4735 btrfs_crit(root
->fs_info
, "not enough freespace need %u have %d",
4736 total_size
, btrfs_leaf_free_space(root
, leaf
));
4740 if (slot
!= nritems
) {
4741 unsigned int old_data
= btrfs_item_end_nr(leaf
, slot
);
4743 if (old_data
< data_end
) {
4744 btrfs_print_leaf(root
, leaf
);
4745 btrfs_crit(root
->fs_info
, "slot %d old_data %d data_end %d",
4746 slot
, old_data
, data_end
);
4750 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4752 /* first correct the data pointers */
4753 for (i
= slot
; i
< nritems
; i
++) {
4756 item
= btrfs_item_nr( i
);
4757 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4758 btrfs_set_token_item_offset(leaf
, item
,
4759 ioff
- total_data
, &token
);
4761 /* shift the items */
4762 memmove_extent_buffer(leaf
, btrfs_item_nr_offset(slot
+ nr
),
4763 btrfs_item_nr_offset(slot
),
4764 (nritems
- slot
) * sizeof(struct btrfs_item
));
4766 /* shift the data */
4767 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4768 data_end
- total_data
, btrfs_leaf_data(leaf
) +
4769 data_end
, old_data
- data_end
);
4770 data_end
= old_data
;
4773 /* setup the item for the new data */
4774 for (i
= 0; i
< nr
; i
++) {
4775 btrfs_cpu_key_to_disk(&disk_key
, cpu_key
+ i
);
4776 btrfs_set_item_key(leaf
, &disk_key
, slot
+ i
);
4777 item
= btrfs_item_nr(slot
+ i
);
4778 btrfs_set_token_item_offset(leaf
, item
,
4779 data_end
- data_size
[i
], &token
);
4780 data_end
-= data_size
[i
];
4781 btrfs_set_token_item_size(leaf
, item
, data_size
[i
], &token
);
4784 btrfs_set_header_nritems(leaf
, nritems
+ nr
);
4785 btrfs_mark_buffer_dirty(leaf
);
4787 if (btrfs_leaf_free_space(root
, leaf
) < 0) {
4788 btrfs_print_leaf(root
, leaf
);
4794 * Given a key and some data, insert items into the tree.
4795 * This does all the path init required, making room in the tree if needed.
4797 int btrfs_insert_empty_items(struct btrfs_trans_handle
*trans
,
4798 struct btrfs_root
*root
,
4799 struct btrfs_path
*path
,
4800 struct btrfs_key
*cpu_key
, u32
*data_size
,
4809 for (i
= 0; i
< nr
; i
++)
4810 total_data
+= data_size
[i
];
4812 total_size
= total_data
+ (nr
* sizeof(struct btrfs_item
));
4813 ret
= btrfs_search_slot(trans
, root
, cpu_key
, path
, total_size
, 1);
4819 slot
= path
->slots
[0];
4822 setup_items_for_insert(root
, path
, cpu_key
, data_size
,
4823 total_data
, total_size
, nr
);
4828 * Given a key and some data, insert an item into the tree.
4829 * This does all the path init required, making room in the tree if needed.
4831 int btrfs_insert_item(struct btrfs_trans_handle
*trans
, struct btrfs_root
4832 *root
, struct btrfs_key
*cpu_key
, void *data
, u32
4836 struct btrfs_path
*path
;
4837 struct extent_buffer
*leaf
;
4840 path
= btrfs_alloc_path();
4843 ret
= btrfs_insert_empty_item(trans
, root
, path
, cpu_key
, data_size
);
4845 leaf
= path
->nodes
[0];
4846 ptr
= btrfs_item_ptr_offset(leaf
, path
->slots
[0]);
4847 write_extent_buffer(leaf
, data
, ptr
, data_size
);
4848 btrfs_mark_buffer_dirty(leaf
);
4850 btrfs_free_path(path
);
4855 * delete the pointer from a given node.
4857 * the tree should have been previously balanced so the deletion does not
4860 static void del_ptr(struct btrfs_root
*root
, struct btrfs_path
*path
,
4861 int level
, int slot
)
4863 struct extent_buffer
*parent
= path
->nodes
[level
];
4867 nritems
= btrfs_header_nritems(parent
);
4868 if (slot
!= nritems
- 1) {
4870 tree_mod_log_eb_move(root
->fs_info
, parent
, slot
,
4871 slot
+ 1, nritems
- slot
- 1);
4872 memmove_extent_buffer(parent
,
4873 btrfs_node_key_ptr_offset(slot
),
4874 btrfs_node_key_ptr_offset(slot
+ 1),
4875 sizeof(struct btrfs_key_ptr
) *
4876 (nritems
- slot
- 1));
4878 ret
= tree_mod_log_insert_key(root
->fs_info
, parent
, slot
,
4879 MOD_LOG_KEY_REMOVE
, GFP_NOFS
);
4884 btrfs_set_header_nritems(parent
, nritems
);
4885 if (nritems
== 0 && parent
== root
->node
) {
4886 BUG_ON(btrfs_header_level(root
->node
) != 1);
4887 /* just turn the root into a leaf and break */
4888 btrfs_set_header_level(root
->node
, 0);
4889 } else if (slot
== 0) {
4890 struct btrfs_disk_key disk_key
;
4892 btrfs_node_key(parent
, &disk_key
, 0);
4893 fixup_low_keys(root
->fs_info
, path
, &disk_key
, level
+ 1);
4895 btrfs_mark_buffer_dirty(parent
);
4899 * a helper function to delete the leaf pointed to by path->slots[1] and
4902 * This deletes the pointer in path->nodes[1] and frees the leaf
4903 * block extent. zero is returned if it all worked out, < 0 otherwise.
4905 * The path must have already been setup for deleting the leaf, including
4906 * all the proper balancing. path->nodes[1] must be locked.
4908 static noinline
void btrfs_del_leaf(struct btrfs_trans_handle
*trans
,
4909 struct btrfs_root
*root
,
4910 struct btrfs_path
*path
,
4911 struct extent_buffer
*leaf
)
4913 WARN_ON(btrfs_header_generation(leaf
) != trans
->transid
);
4914 del_ptr(root
, path
, 1, path
->slots
[1]);
4917 * btrfs_free_extent is expensive, we want to make sure we
4918 * aren't holding any locks when we call it
4920 btrfs_unlock_up_safe(path
, 0);
4922 root_sub_used(root
, leaf
->len
);
4924 extent_buffer_get(leaf
);
4925 btrfs_free_tree_block(trans
, root
, leaf
, 0, 1);
4926 free_extent_buffer_stale(leaf
);
4929 * delete the item at the leaf level in path. If that empties
4930 * the leaf, remove it from the tree
4932 int btrfs_del_items(struct btrfs_trans_handle
*trans
, struct btrfs_root
*root
,
4933 struct btrfs_path
*path
, int slot
, int nr
)
4935 struct extent_buffer
*leaf
;
4936 struct btrfs_item
*item
;
4943 struct btrfs_map_token token
;
4945 btrfs_init_map_token(&token
);
4947 leaf
= path
->nodes
[0];
4948 last_off
= btrfs_item_offset_nr(leaf
, slot
+ nr
- 1);
4950 for (i
= 0; i
< nr
; i
++)
4951 dsize
+= btrfs_item_size_nr(leaf
, slot
+ i
);
4953 nritems
= btrfs_header_nritems(leaf
);
4955 if (slot
+ nr
!= nritems
) {
4956 int data_end
= leaf_data_end(root
, leaf
);
4958 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4960 btrfs_leaf_data(leaf
) + data_end
,
4961 last_off
- data_end
);
4963 for (i
= slot
+ nr
; i
< nritems
; i
++) {
4966 item
= btrfs_item_nr(i
);
4967 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4968 btrfs_set_token_item_offset(leaf
, item
,
4969 ioff
+ dsize
, &token
);
4972 memmove_extent_buffer(leaf
, btrfs_item_nr_offset(slot
),
4973 btrfs_item_nr_offset(slot
+ nr
),
4974 sizeof(struct btrfs_item
) *
4975 (nritems
- slot
- nr
));
4977 btrfs_set_header_nritems(leaf
, nritems
- nr
);
4980 /* delete the leaf if we've emptied it */
4982 if (leaf
== root
->node
) {
4983 btrfs_set_header_level(leaf
, 0);
4985 btrfs_set_path_blocking(path
);
4986 clean_tree_block(trans
, root
->fs_info
, leaf
);
4987 btrfs_del_leaf(trans
, root
, path
, leaf
);
4990 int used
= leaf_space_used(leaf
, 0, nritems
);
4992 struct btrfs_disk_key disk_key
;
4994 btrfs_item_key(leaf
, &disk_key
, 0);
4995 fixup_low_keys(root
->fs_info
, path
, &disk_key
, 1);
4998 /* delete the leaf if it is mostly empty */
4999 if (used
< BTRFS_LEAF_DATA_SIZE(root
) / 3) {
5000 /* push_leaf_left fixes the path.
5001 * make sure the path still points to our leaf
5002 * for possible call to del_ptr below
5004 slot
= path
->slots
[1];
5005 extent_buffer_get(leaf
);
5007 btrfs_set_path_blocking(path
);
5008 wret
= push_leaf_left(trans
, root
, path
, 1, 1,
5010 if (wret
< 0 && wret
!= -ENOSPC
)
5013 if (path
->nodes
[0] == leaf
&&
5014 btrfs_header_nritems(leaf
)) {
5015 wret
= push_leaf_right(trans
, root
, path
, 1,
5017 if (wret
< 0 && wret
!= -ENOSPC
)
5021 if (btrfs_header_nritems(leaf
) == 0) {
5022 path
->slots
[1] = slot
;
5023 btrfs_del_leaf(trans
, root
, path
, leaf
);
5024 free_extent_buffer(leaf
);
5027 /* if we're still in the path, make sure
5028 * we're dirty. Otherwise, one of the
5029 * push_leaf functions must have already
5030 * dirtied this buffer
5032 if (path
->nodes
[0] == leaf
)
5033 btrfs_mark_buffer_dirty(leaf
);
5034 free_extent_buffer(leaf
);
5037 btrfs_mark_buffer_dirty(leaf
);
5044 * search the tree again to find a leaf with lesser keys
5045 * returns 0 if it found something or 1 if there are no lesser leaves.
5046 * returns < 0 on io errors.
5048 * This may release the path, and so you may lose any locks held at the
5051 int btrfs_prev_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
)
5053 struct btrfs_key key
;
5054 struct btrfs_disk_key found_key
;
5057 btrfs_item_key_to_cpu(path
->nodes
[0], &key
, 0);
5059 if (key
.offset
> 0) {
5061 } else if (key
.type
> 0) {
5063 key
.offset
= (u64
)-1;
5064 } else if (key
.objectid
> 0) {
5067 key
.offset
= (u64
)-1;
5072 btrfs_release_path(path
);
5073 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
5076 btrfs_item_key(path
->nodes
[0], &found_key
, 0);
5077 ret
= comp_keys(&found_key
, &key
);
5079 * We might have had an item with the previous key in the tree right
5080 * before we released our path. And after we released our path, that
5081 * item might have been pushed to the first slot (0) of the leaf we
5082 * were holding due to a tree balance. Alternatively, an item with the
5083 * previous key can exist as the only element of a leaf (big fat item).
5084 * Therefore account for these 2 cases, so that our callers (like
5085 * btrfs_previous_item) don't miss an existing item with a key matching
5086 * the previous key we computed above.
5094 * A helper function to walk down the tree starting at min_key, and looking
5095 * for nodes or leaves that are have a minimum transaction id.
5096 * This is used by the btree defrag code, and tree logging
5098 * This does not cow, but it does stuff the starting key it finds back
5099 * into min_key, so you can call btrfs_search_slot with cow=1 on the
5100 * key and get a writable path.
5102 * This does lock as it descends, and path->keep_locks should be set
5103 * to 1 by the caller.
5105 * This honors path->lowest_level to prevent descent past a given level
5108 * min_trans indicates the oldest transaction that you are interested
5109 * in walking through. Any nodes or leaves older than min_trans are
5110 * skipped over (without reading them).
5112 * returns zero if something useful was found, < 0 on error and 1 if there
5113 * was nothing in the tree that matched the search criteria.
5115 int btrfs_search_forward(struct btrfs_root
*root
, struct btrfs_key
*min_key
,
5116 struct btrfs_path
*path
,
5119 struct extent_buffer
*cur
;
5120 struct btrfs_key found_key
;
5126 int keep_locks
= path
->keep_locks
;
5128 path
->keep_locks
= 1;
5130 cur
= btrfs_read_lock_root_node(root
);
5131 level
= btrfs_header_level(cur
);
5132 WARN_ON(path
->nodes
[level
]);
5133 path
->nodes
[level
] = cur
;
5134 path
->locks
[level
] = BTRFS_READ_LOCK
;
5136 if (btrfs_header_generation(cur
) < min_trans
) {
5141 nritems
= btrfs_header_nritems(cur
);
5142 level
= btrfs_header_level(cur
);
5143 sret
= bin_search(cur
, min_key
, level
, &slot
);
5145 /* at the lowest level, we're done, setup the path and exit */
5146 if (level
== path
->lowest_level
) {
5147 if (slot
>= nritems
)
5150 path
->slots
[level
] = slot
;
5151 btrfs_item_key_to_cpu(cur
, &found_key
, slot
);
5154 if (sret
&& slot
> 0)
5157 * check this node pointer against the min_trans parameters.
5158 * If it is too old, old, skip to the next one.
5160 while (slot
< nritems
) {
5163 gen
= btrfs_node_ptr_generation(cur
, slot
);
5164 if (gen
< min_trans
) {
5172 * we didn't find a candidate key in this node, walk forward
5173 * and find another one
5175 if (slot
>= nritems
) {
5176 path
->slots
[level
] = slot
;
5177 btrfs_set_path_blocking(path
);
5178 sret
= btrfs_find_next_key(root
, path
, min_key
, level
,
5181 btrfs_release_path(path
);
5187 /* save our key for returning back */
5188 btrfs_node_key_to_cpu(cur
, &found_key
, slot
);
5189 path
->slots
[level
] = slot
;
5190 if (level
== path
->lowest_level
) {
5194 btrfs_set_path_blocking(path
);
5195 cur
= read_node_slot(root
, cur
, slot
);
5196 BUG_ON(!cur
); /* -ENOMEM */
5198 btrfs_tree_read_lock(cur
);
5200 path
->locks
[level
- 1] = BTRFS_READ_LOCK
;
5201 path
->nodes
[level
- 1] = cur
;
5202 unlock_up(path
, level
, 1, 0, NULL
);
5203 btrfs_clear_path_blocking(path
, NULL
, 0);
5206 path
->keep_locks
= keep_locks
;
5208 btrfs_unlock_up_safe(path
, path
->lowest_level
+ 1);
5209 btrfs_set_path_blocking(path
);
5210 memcpy(min_key
, &found_key
, sizeof(found_key
));
5215 static void tree_move_down(struct btrfs_root
*root
,
5216 struct btrfs_path
*path
,
5217 int *level
, int root_level
)
5219 BUG_ON(*level
== 0);
5220 path
->nodes
[*level
- 1] = read_node_slot(root
, path
->nodes
[*level
],
5221 path
->slots
[*level
]);
5222 path
->slots
[*level
- 1] = 0;
5226 static int tree_move_next_or_upnext(struct btrfs_root
*root
,
5227 struct btrfs_path
*path
,
5228 int *level
, int root_level
)
5232 nritems
= btrfs_header_nritems(path
->nodes
[*level
]);
5234 path
->slots
[*level
]++;
5236 while (path
->slots
[*level
] >= nritems
) {
5237 if (*level
== root_level
)
5241 path
->slots
[*level
] = 0;
5242 free_extent_buffer(path
->nodes
[*level
]);
5243 path
->nodes
[*level
] = NULL
;
5245 path
->slots
[*level
]++;
5247 nritems
= btrfs_header_nritems(path
->nodes
[*level
]);
5254 * Returns 1 if it had to move up and next. 0 is returned if it moved only next
5257 static int tree_advance(struct btrfs_root
*root
,
5258 struct btrfs_path
*path
,
5259 int *level
, int root_level
,
5261 struct btrfs_key
*key
)
5265 if (*level
== 0 || !allow_down
) {
5266 ret
= tree_move_next_or_upnext(root
, path
, level
, root_level
);
5268 tree_move_down(root
, path
, level
, root_level
);
5273 btrfs_item_key_to_cpu(path
->nodes
[*level
], key
,
5274 path
->slots
[*level
]);
5276 btrfs_node_key_to_cpu(path
->nodes
[*level
], key
,
5277 path
->slots
[*level
]);
5282 static int tree_compare_item(struct btrfs_root
*left_root
,
5283 struct btrfs_path
*left_path
,
5284 struct btrfs_path
*right_path
,
5289 unsigned long off1
, off2
;
5291 len1
= btrfs_item_size_nr(left_path
->nodes
[0], left_path
->slots
[0]);
5292 len2
= btrfs_item_size_nr(right_path
->nodes
[0], right_path
->slots
[0]);
5296 off1
= btrfs_item_ptr_offset(left_path
->nodes
[0], left_path
->slots
[0]);
5297 off2
= btrfs_item_ptr_offset(right_path
->nodes
[0],
5298 right_path
->slots
[0]);
5300 read_extent_buffer(left_path
->nodes
[0], tmp_buf
, off1
, len1
);
5302 cmp
= memcmp_extent_buffer(right_path
->nodes
[0], tmp_buf
, off2
, len1
);
5309 #define ADVANCE_ONLY_NEXT -1
5312 * This function compares two trees and calls the provided callback for
5313 * every changed/new/deleted item it finds.
5314 * If shared tree blocks are encountered, whole subtrees are skipped, making
5315 * the compare pretty fast on snapshotted subvolumes.
5317 * This currently works on commit roots only. As commit roots are read only,
5318 * we don't do any locking. The commit roots are protected with transactions.
5319 * Transactions are ended and rejoined when a commit is tried in between.
5321 * This function checks for modifications done to the trees while comparing.
5322 * If it detects a change, it aborts immediately.
5324 int btrfs_compare_trees(struct btrfs_root
*left_root
,
5325 struct btrfs_root
*right_root
,
5326 btrfs_changed_cb_t changed_cb
, void *ctx
)
5330 struct btrfs_path
*left_path
= NULL
;
5331 struct btrfs_path
*right_path
= NULL
;
5332 struct btrfs_key left_key
;
5333 struct btrfs_key right_key
;
5334 char *tmp_buf
= NULL
;
5335 int left_root_level
;
5336 int right_root_level
;
5339 int left_end_reached
;
5340 int right_end_reached
;
5348 left_path
= btrfs_alloc_path();
5353 right_path
= btrfs_alloc_path();
5359 tmp_buf
= kmalloc(left_root
->nodesize
, GFP_NOFS
);
5365 left_path
->search_commit_root
= 1;
5366 left_path
->skip_locking
= 1;
5367 right_path
->search_commit_root
= 1;
5368 right_path
->skip_locking
= 1;
5371 * Strategy: Go to the first items of both trees. Then do
5373 * If both trees are at level 0
5374 * Compare keys of current items
5375 * If left < right treat left item as new, advance left tree
5377 * If left > right treat right item as deleted, advance right tree
5379 * If left == right do deep compare of items, treat as changed if
5380 * needed, advance both trees and repeat
5381 * If both trees are at the same level but not at level 0
5382 * Compare keys of current nodes/leafs
5383 * If left < right advance left tree and repeat
5384 * If left > right advance right tree and repeat
5385 * If left == right compare blockptrs of the next nodes/leafs
5386 * If they match advance both trees but stay at the same level
5388 * If they don't match advance both trees while allowing to go
5390 * If tree levels are different
5391 * Advance the tree that needs it and repeat
5393 * Advancing a tree means:
5394 * If we are at level 0, try to go to the next slot. If that's not
5395 * possible, go one level up and repeat. Stop when we found a level
5396 * where we could go to the next slot. We may at this point be on a
5399 * If we are not at level 0 and not on shared tree blocks, go one
5402 * If we are not at level 0 and on shared tree blocks, go one slot to
5403 * the right if possible or go up and right.
5406 down_read(&left_root
->fs_info
->commit_root_sem
);
5407 left_level
= btrfs_header_level(left_root
->commit_root
);
5408 left_root_level
= left_level
;
5409 left_path
->nodes
[left_level
] = left_root
->commit_root
;
5410 extent_buffer_get(left_path
->nodes
[left_level
]);
5412 right_level
= btrfs_header_level(right_root
->commit_root
);
5413 right_root_level
= right_level
;
5414 right_path
->nodes
[right_level
] = right_root
->commit_root
;
5415 extent_buffer_get(right_path
->nodes
[right_level
]);
5416 up_read(&left_root
->fs_info
->commit_root_sem
);
5418 if (left_level
== 0)
5419 btrfs_item_key_to_cpu(left_path
->nodes
[left_level
],
5420 &left_key
, left_path
->slots
[left_level
]);
5422 btrfs_node_key_to_cpu(left_path
->nodes
[left_level
],
5423 &left_key
, left_path
->slots
[left_level
]);
5424 if (right_level
== 0)
5425 btrfs_item_key_to_cpu(right_path
->nodes
[right_level
],
5426 &right_key
, right_path
->slots
[right_level
]);
5428 btrfs_node_key_to_cpu(right_path
->nodes
[right_level
],
5429 &right_key
, right_path
->slots
[right_level
]);
5431 left_end_reached
= right_end_reached
= 0;
5432 advance_left
= advance_right
= 0;
5435 if (advance_left
&& !left_end_reached
) {
5436 ret
= tree_advance(left_root
, left_path
, &left_level
,
5438 advance_left
!= ADVANCE_ONLY_NEXT
,
5441 left_end_reached
= ADVANCE
;
5444 if (advance_right
&& !right_end_reached
) {
5445 ret
= tree_advance(right_root
, right_path
, &right_level
,
5447 advance_right
!= ADVANCE_ONLY_NEXT
,
5450 right_end_reached
= ADVANCE
;
5454 if (left_end_reached
&& right_end_reached
) {
5457 } else if (left_end_reached
) {
5458 if (right_level
== 0) {
5459 ret
= changed_cb(left_root
, right_root
,
5460 left_path
, right_path
,
5462 BTRFS_COMPARE_TREE_DELETED
,
5467 advance_right
= ADVANCE
;
5469 } else if (right_end_reached
) {
5470 if (left_level
== 0) {
5471 ret
= changed_cb(left_root
, right_root
,
5472 left_path
, right_path
,
5474 BTRFS_COMPARE_TREE_NEW
,
5479 advance_left
= ADVANCE
;
5483 if (left_level
== 0 && right_level
== 0) {
5484 cmp
= btrfs_comp_cpu_keys(&left_key
, &right_key
);
5486 ret
= changed_cb(left_root
, right_root
,
5487 left_path
, right_path
,
5489 BTRFS_COMPARE_TREE_NEW
,
5493 advance_left
= ADVANCE
;
5494 } else if (cmp
> 0) {
5495 ret
= changed_cb(left_root
, right_root
,
5496 left_path
, right_path
,
5498 BTRFS_COMPARE_TREE_DELETED
,
5502 advance_right
= ADVANCE
;
5504 enum btrfs_compare_tree_result result
;
5506 WARN_ON(!extent_buffer_uptodate(left_path
->nodes
[0]));
5507 ret
= tree_compare_item(left_root
, left_path
,
5508 right_path
, tmp_buf
);
5510 result
= BTRFS_COMPARE_TREE_CHANGED
;
5512 result
= BTRFS_COMPARE_TREE_SAME
;
5513 ret
= changed_cb(left_root
, right_root
,
5514 left_path
, right_path
,
5515 &left_key
, result
, ctx
);
5518 advance_left
= ADVANCE
;
5519 advance_right
= ADVANCE
;
5521 } else if (left_level
== right_level
) {
5522 cmp
= btrfs_comp_cpu_keys(&left_key
, &right_key
);
5524 advance_left
= ADVANCE
;
5525 } else if (cmp
> 0) {
5526 advance_right
= ADVANCE
;
5528 left_blockptr
= btrfs_node_blockptr(
5529 left_path
->nodes
[left_level
],
5530 left_path
->slots
[left_level
]);
5531 right_blockptr
= btrfs_node_blockptr(
5532 right_path
->nodes
[right_level
],
5533 right_path
->slots
[right_level
]);
5534 left_gen
= btrfs_node_ptr_generation(
5535 left_path
->nodes
[left_level
],
5536 left_path
->slots
[left_level
]);
5537 right_gen
= btrfs_node_ptr_generation(
5538 right_path
->nodes
[right_level
],
5539 right_path
->slots
[right_level
]);
5540 if (left_blockptr
== right_blockptr
&&
5541 left_gen
== right_gen
) {
5543 * As we're on a shared block, don't
5544 * allow to go deeper.
5546 advance_left
= ADVANCE_ONLY_NEXT
;
5547 advance_right
= ADVANCE_ONLY_NEXT
;
5549 advance_left
= ADVANCE
;
5550 advance_right
= ADVANCE
;
5553 } else if (left_level
< right_level
) {
5554 advance_right
= ADVANCE
;
5556 advance_left
= ADVANCE
;
5561 btrfs_free_path(left_path
);
5562 btrfs_free_path(right_path
);
5568 * this is similar to btrfs_next_leaf, but does not try to preserve
5569 * and fixup the path. It looks for and returns the next key in the
5570 * tree based on the current path and the min_trans parameters.
5572 * 0 is returned if another key is found, < 0 if there are any errors
5573 * and 1 is returned if there are no higher keys in the tree
5575 * path->keep_locks should be set to 1 on the search made before
5576 * calling this function.
5578 int btrfs_find_next_key(struct btrfs_root
*root
, struct btrfs_path
*path
,
5579 struct btrfs_key
*key
, int level
, u64 min_trans
)
5582 struct extent_buffer
*c
;
5584 WARN_ON(!path
->keep_locks
);
5585 while (level
< BTRFS_MAX_LEVEL
) {
5586 if (!path
->nodes
[level
])
5589 slot
= path
->slots
[level
] + 1;
5590 c
= path
->nodes
[level
];
5592 if (slot
>= btrfs_header_nritems(c
)) {
5595 struct btrfs_key cur_key
;
5596 if (level
+ 1 >= BTRFS_MAX_LEVEL
||
5597 !path
->nodes
[level
+ 1])
5600 if (path
->locks
[level
+ 1]) {
5605 slot
= btrfs_header_nritems(c
) - 1;
5607 btrfs_item_key_to_cpu(c
, &cur_key
, slot
);
5609 btrfs_node_key_to_cpu(c
, &cur_key
, slot
);
5611 orig_lowest
= path
->lowest_level
;
5612 btrfs_release_path(path
);
5613 path
->lowest_level
= level
;
5614 ret
= btrfs_search_slot(NULL
, root
, &cur_key
, path
,
5616 path
->lowest_level
= orig_lowest
;
5620 c
= path
->nodes
[level
];
5621 slot
= path
->slots
[level
];
5628 btrfs_item_key_to_cpu(c
, key
, slot
);
5630 u64 gen
= btrfs_node_ptr_generation(c
, slot
);
5632 if (gen
< min_trans
) {
5636 btrfs_node_key_to_cpu(c
, key
, slot
);
5644 * search the tree again to find a leaf with greater keys
5645 * returns 0 if it found something or 1 if there are no greater leaves.
5646 * returns < 0 on io errors.
5648 int btrfs_next_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
)
5650 return btrfs_next_old_leaf(root
, path
, 0);
5653 int btrfs_next_old_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
,
5658 struct extent_buffer
*c
;
5659 struct extent_buffer
*next
;
5660 struct btrfs_key key
;
5663 int old_spinning
= path
->leave_spinning
;
5664 int next_rw_lock
= 0;
5666 nritems
= btrfs_header_nritems(path
->nodes
[0]);
5670 btrfs_item_key_to_cpu(path
->nodes
[0], &key
, nritems
- 1);
5675 btrfs_release_path(path
);
5677 path
->keep_locks
= 1;
5678 path
->leave_spinning
= 1;
5681 ret
= btrfs_search_old_slot(root
, &key
, path
, time_seq
);
5683 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
5684 path
->keep_locks
= 0;
5689 nritems
= btrfs_header_nritems(path
->nodes
[0]);
5691 * by releasing the path above we dropped all our locks. A balance
5692 * could have added more items next to the key that used to be
5693 * at the very end of the block. So, check again here and
5694 * advance the path if there are now more items available.
5696 if (nritems
> 0 && path
->slots
[0] < nritems
- 1) {
5703 * So the above check misses one case:
5704 * - after releasing the path above, someone has removed the item that
5705 * used to be at the very end of the block, and balance between leafs
5706 * gets another one with bigger key.offset to replace it.
5708 * This one should be returned as well, or we can get leaf corruption
5709 * later(esp. in __btrfs_drop_extents()).
5711 * And a bit more explanation about this check,
5712 * with ret > 0, the key isn't found, the path points to the slot
5713 * where it should be inserted, so the path->slots[0] item must be the
5716 if (nritems
> 0 && ret
> 0 && path
->slots
[0] == nritems
- 1) {
5721 while (level
< BTRFS_MAX_LEVEL
) {
5722 if (!path
->nodes
[level
]) {
5727 slot
= path
->slots
[level
] + 1;
5728 c
= path
->nodes
[level
];
5729 if (slot
>= btrfs_header_nritems(c
)) {
5731 if (level
== BTRFS_MAX_LEVEL
) {
5739 btrfs_tree_unlock_rw(next
, next_rw_lock
);
5740 free_extent_buffer(next
);
5744 next_rw_lock
= path
->locks
[level
];
5745 ret
= read_block_for_search(NULL
, root
, path
, &next
, level
,
5751 btrfs_release_path(path
);
5755 if (!path
->skip_locking
) {
5756 ret
= btrfs_try_tree_read_lock(next
);
5757 if (!ret
&& time_seq
) {
5759 * If we don't get the lock, we may be racing
5760 * with push_leaf_left, holding that lock while
5761 * itself waiting for the leaf we've currently
5762 * locked. To solve this situation, we give up
5763 * on our lock and cycle.
5765 free_extent_buffer(next
);
5766 btrfs_release_path(path
);
5771 btrfs_set_path_blocking(path
);
5772 btrfs_tree_read_lock(next
);
5773 btrfs_clear_path_blocking(path
, next
,
5776 next_rw_lock
= BTRFS_READ_LOCK
;
5780 path
->slots
[level
] = slot
;
5783 c
= path
->nodes
[level
];
5784 if (path
->locks
[level
])
5785 btrfs_tree_unlock_rw(c
, path
->locks
[level
]);
5787 free_extent_buffer(c
);
5788 path
->nodes
[level
] = next
;
5789 path
->slots
[level
] = 0;
5790 if (!path
->skip_locking
)
5791 path
->locks
[level
] = next_rw_lock
;
5795 ret
= read_block_for_search(NULL
, root
, path
, &next
, level
,
5801 btrfs_release_path(path
);
5805 if (!path
->skip_locking
) {
5806 ret
= btrfs_try_tree_read_lock(next
);
5808 btrfs_set_path_blocking(path
);
5809 btrfs_tree_read_lock(next
);
5810 btrfs_clear_path_blocking(path
, next
,
5813 next_rw_lock
= BTRFS_READ_LOCK
;
5818 unlock_up(path
, 0, 1, 0, NULL
);
5819 path
->leave_spinning
= old_spinning
;
5821 btrfs_set_path_blocking(path
);
5827 * this uses btrfs_prev_leaf to walk backwards in the tree, and keeps
5828 * searching until it gets past min_objectid or finds an item of 'type'
5830 * returns 0 if something is found, 1 if nothing was found and < 0 on error
5832 int btrfs_previous_item(struct btrfs_root
*root
,
5833 struct btrfs_path
*path
, u64 min_objectid
,
5836 struct btrfs_key found_key
;
5837 struct extent_buffer
*leaf
;
5842 if (path
->slots
[0] == 0) {
5843 btrfs_set_path_blocking(path
);
5844 ret
= btrfs_prev_leaf(root
, path
);
5850 leaf
= path
->nodes
[0];
5851 nritems
= btrfs_header_nritems(leaf
);
5854 if (path
->slots
[0] == nritems
)
5857 btrfs_item_key_to_cpu(leaf
, &found_key
, path
->slots
[0]);
5858 if (found_key
.objectid
< min_objectid
)
5860 if (found_key
.type
== type
)
5862 if (found_key
.objectid
== min_objectid
&&
5863 found_key
.type
< type
)
5870 * search in extent tree to find a previous Metadata/Data extent item with
5873 * returns 0 if something is found, 1 if nothing was found and < 0 on error
5875 int btrfs_previous_extent_item(struct btrfs_root
*root
,
5876 struct btrfs_path
*path
, u64 min_objectid
)
5878 struct btrfs_key found_key
;
5879 struct extent_buffer
*leaf
;
5884 if (path
->slots
[0] == 0) {
5885 btrfs_set_path_blocking(path
);
5886 ret
= btrfs_prev_leaf(root
, path
);
5892 leaf
= path
->nodes
[0];
5893 nritems
= btrfs_header_nritems(leaf
);
5896 if (path
->slots
[0] == nritems
)
5899 btrfs_item_key_to_cpu(leaf
, &found_key
, path
->slots
[0]);
5900 if (found_key
.objectid
< min_objectid
)
5902 if (found_key
.type
== BTRFS_EXTENT_ITEM_KEY
||
5903 found_key
.type
== BTRFS_METADATA_ITEM_KEY
)
5905 if (found_key
.objectid
== min_objectid
&&
5906 found_key
.type
< BTRFS_EXTENT_ITEM_KEY
)