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>
22 #include <linux/vmalloc.h>
25 #include "transaction.h"
26 #include "print-tree.h"
29 static int split_node(struct btrfs_trans_handle
*trans
, struct btrfs_root
30 *root
, struct btrfs_path
*path
, int level
);
31 static int split_leaf(struct btrfs_trans_handle
*trans
, struct btrfs_root
32 *root
, struct btrfs_key
*ins_key
,
33 struct btrfs_path
*path
, int data_size
, int extend
);
34 static int push_node_left(struct btrfs_trans_handle
*trans
,
35 struct btrfs_root
*root
, struct extent_buffer
*dst
,
36 struct extent_buffer
*src
, int empty
);
37 static int balance_node_right(struct btrfs_trans_handle
*trans
,
38 struct btrfs_root
*root
,
39 struct extent_buffer
*dst_buf
,
40 struct extent_buffer
*src_buf
);
41 static void del_ptr(struct btrfs_root
*root
, struct btrfs_path
*path
,
43 static int tree_mod_log_free_eb(struct btrfs_fs_info
*fs_info
,
44 struct extent_buffer
*eb
);
46 struct btrfs_path
*btrfs_alloc_path(void)
48 return kmem_cache_zalloc(btrfs_path_cachep
, GFP_NOFS
);
52 * set all locked nodes in the path to blocking locks. This should
53 * be done before scheduling
55 noinline
void btrfs_set_path_blocking(struct btrfs_path
*p
)
58 for (i
= 0; i
< BTRFS_MAX_LEVEL
; i
++) {
59 if (!p
->nodes
[i
] || !p
->locks
[i
])
61 btrfs_set_lock_blocking_rw(p
->nodes
[i
], p
->locks
[i
]);
62 if (p
->locks
[i
] == BTRFS_READ_LOCK
)
63 p
->locks
[i
] = BTRFS_READ_LOCK_BLOCKING
;
64 else if (p
->locks
[i
] == BTRFS_WRITE_LOCK
)
65 p
->locks
[i
] = BTRFS_WRITE_LOCK_BLOCKING
;
70 * reset all the locked nodes in the patch to spinning locks.
72 * held is used to keep lockdep happy, when lockdep is enabled
73 * we set held to a blocking lock before we go around and
74 * retake all the spinlocks in the path. You can safely use NULL
77 noinline
void btrfs_clear_path_blocking(struct btrfs_path
*p
,
78 struct extent_buffer
*held
, int held_rw
)
83 btrfs_set_lock_blocking_rw(held
, held_rw
);
84 if (held_rw
== BTRFS_WRITE_LOCK
)
85 held_rw
= BTRFS_WRITE_LOCK_BLOCKING
;
86 else if (held_rw
== BTRFS_READ_LOCK
)
87 held_rw
= BTRFS_READ_LOCK_BLOCKING
;
89 btrfs_set_path_blocking(p
);
91 for (i
= BTRFS_MAX_LEVEL
- 1; i
>= 0; i
--) {
92 if (p
->nodes
[i
] && p
->locks
[i
]) {
93 btrfs_clear_lock_blocking_rw(p
->nodes
[i
], p
->locks
[i
]);
94 if (p
->locks
[i
] == BTRFS_WRITE_LOCK_BLOCKING
)
95 p
->locks
[i
] = BTRFS_WRITE_LOCK
;
96 else if (p
->locks
[i
] == BTRFS_READ_LOCK_BLOCKING
)
97 p
->locks
[i
] = BTRFS_READ_LOCK
;
102 btrfs_clear_lock_blocking_rw(held
, held_rw
);
105 /* this also releases the path */
106 void btrfs_free_path(struct btrfs_path
*p
)
110 btrfs_release_path(p
);
111 kmem_cache_free(btrfs_path_cachep
, p
);
115 * path release drops references on the extent buffers in the path
116 * and it drops any locks held by this path
118 * It is safe to call this on paths that no locks or extent buffers held.
120 noinline
void btrfs_release_path(struct btrfs_path
*p
)
124 for (i
= 0; i
< BTRFS_MAX_LEVEL
; i
++) {
129 btrfs_tree_unlock_rw(p
->nodes
[i
], p
->locks
[i
]);
132 free_extent_buffer(p
->nodes
[i
]);
138 * safely gets a reference on the root node of a tree. A lock
139 * is not taken, so a concurrent writer may put a different node
140 * at the root of the tree. See btrfs_lock_root_node for the
143 * The extent buffer returned by this has a reference taken, so
144 * it won't disappear. It may stop being the root of the tree
145 * at any time because there are no locks held.
147 struct extent_buffer
*btrfs_root_node(struct btrfs_root
*root
)
149 struct extent_buffer
*eb
;
153 eb
= rcu_dereference(root
->node
);
156 * RCU really hurts here, we could free up the root node because
157 * it was COWed but we may not get the new root node yet so do
158 * the inc_not_zero dance and if it doesn't work then
159 * synchronize_rcu and try again.
161 if (atomic_inc_not_zero(&eb
->refs
)) {
171 /* loop around taking references on and locking the root node of the
172 * tree until you end up with a lock on the root. A locked buffer
173 * is returned, with a reference held.
175 struct extent_buffer
*btrfs_lock_root_node(struct btrfs_root
*root
)
177 struct extent_buffer
*eb
;
180 eb
= btrfs_root_node(root
);
182 if (eb
== root
->node
)
184 btrfs_tree_unlock(eb
);
185 free_extent_buffer(eb
);
190 /* loop around taking references on and locking the root node of the
191 * tree until you end up with a lock on the root. A locked buffer
192 * is returned, with a reference held.
194 static struct extent_buffer
*btrfs_read_lock_root_node(struct btrfs_root
*root
)
196 struct extent_buffer
*eb
;
199 eb
= btrfs_root_node(root
);
200 btrfs_tree_read_lock(eb
);
201 if (eb
== root
->node
)
203 btrfs_tree_read_unlock(eb
);
204 free_extent_buffer(eb
);
209 /* cowonly root (everything not a reference counted cow subvolume), just get
210 * put onto a simple dirty list. transaction.c walks this to make sure they
211 * get properly updated on disk.
213 static void add_root_to_dirty_list(struct btrfs_root
*root
)
215 if (test_bit(BTRFS_ROOT_DIRTY
, &root
->state
) ||
216 !test_bit(BTRFS_ROOT_TRACK_DIRTY
, &root
->state
))
219 spin_lock(&root
->fs_info
->trans_lock
);
220 if (!test_and_set_bit(BTRFS_ROOT_DIRTY
, &root
->state
)) {
221 /* Want the extent tree to be the last on the list */
222 if (root
->objectid
== BTRFS_EXTENT_TREE_OBJECTID
)
223 list_move_tail(&root
->dirty_list
,
224 &root
->fs_info
->dirty_cowonly_roots
);
226 list_move(&root
->dirty_list
,
227 &root
->fs_info
->dirty_cowonly_roots
);
229 spin_unlock(&root
->fs_info
->trans_lock
);
233 * used by snapshot creation to make a copy of a root for a tree with
234 * a given objectid. The buffer with the new root node is returned in
235 * cow_ret, and this func returns zero on success or a negative error code.
237 int btrfs_copy_root(struct btrfs_trans_handle
*trans
,
238 struct btrfs_root
*root
,
239 struct extent_buffer
*buf
,
240 struct extent_buffer
**cow_ret
, u64 new_root_objectid
)
242 struct extent_buffer
*cow
;
245 struct btrfs_disk_key disk_key
;
247 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
248 trans
->transid
!= root
->fs_info
->running_transaction
->transid
);
249 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
250 trans
->transid
!= root
->last_trans
);
252 level
= btrfs_header_level(buf
);
254 btrfs_item_key(buf
, &disk_key
, 0);
256 btrfs_node_key(buf
, &disk_key
, 0);
258 cow
= btrfs_alloc_tree_block(trans
, root
, 0, new_root_objectid
,
259 &disk_key
, level
, buf
->start
, 0);
263 copy_extent_buffer(cow
, buf
, 0, 0, cow
->len
);
264 btrfs_set_header_bytenr(cow
, cow
->start
);
265 btrfs_set_header_generation(cow
, trans
->transid
);
266 btrfs_set_header_backref_rev(cow
, BTRFS_MIXED_BACKREF_REV
);
267 btrfs_clear_header_flag(cow
, BTRFS_HEADER_FLAG_WRITTEN
|
268 BTRFS_HEADER_FLAG_RELOC
);
269 if (new_root_objectid
== BTRFS_TREE_RELOC_OBJECTID
)
270 btrfs_set_header_flag(cow
, BTRFS_HEADER_FLAG_RELOC
);
272 btrfs_set_header_owner(cow
, new_root_objectid
);
274 write_extent_buffer(cow
, root
->fs_info
->fsid
, btrfs_header_fsid(),
277 WARN_ON(btrfs_header_generation(buf
) > trans
->transid
);
278 if (new_root_objectid
== BTRFS_TREE_RELOC_OBJECTID
)
279 ret
= btrfs_inc_ref(trans
, root
, cow
, 1);
281 ret
= btrfs_inc_ref(trans
, root
, cow
, 0);
286 btrfs_mark_buffer_dirty(cow
);
295 MOD_LOG_KEY_REMOVE_WHILE_FREEING
,
296 MOD_LOG_KEY_REMOVE_WHILE_MOVING
,
298 MOD_LOG_ROOT_REPLACE
,
301 struct tree_mod_move
{
306 struct tree_mod_root
{
311 struct tree_mod_elem
{
317 /* this is used for MOD_LOG_KEY_* and MOD_LOG_MOVE_KEYS operations */
320 /* this is used for MOD_LOG_KEY* and MOD_LOG_ROOT_REPLACE */
323 /* those are used for op == MOD_LOG_KEY_{REPLACE,REMOVE} */
324 struct btrfs_disk_key key
;
327 /* this is used for op == MOD_LOG_MOVE_KEYS */
328 struct tree_mod_move move
;
330 /* this is used for op == MOD_LOG_ROOT_REPLACE */
331 struct tree_mod_root old_root
;
334 static inline void tree_mod_log_read_lock(struct btrfs_fs_info
*fs_info
)
336 read_lock(&fs_info
->tree_mod_log_lock
);
339 static inline void tree_mod_log_read_unlock(struct btrfs_fs_info
*fs_info
)
341 read_unlock(&fs_info
->tree_mod_log_lock
);
344 static inline void tree_mod_log_write_lock(struct btrfs_fs_info
*fs_info
)
346 write_lock(&fs_info
->tree_mod_log_lock
);
349 static inline void tree_mod_log_write_unlock(struct btrfs_fs_info
*fs_info
)
351 write_unlock(&fs_info
->tree_mod_log_lock
);
355 * Pull a new tree mod seq number for our operation.
357 static inline u64
btrfs_inc_tree_mod_seq(struct btrfs_fs_info
*fs_info
)
359 return atomic64_inc_return(&fs_info
->tree_mod_seq
);
363 * This adds a new blocker to the tree mod log's blocker list if the @elem
364 * passed does not already have a sequence number set. So when a caller expects
365 * to record tree modifications, it should ensure to set elem->seq to zero
366 * before calling btrfs_get_tree_mod_seq.
367 * Returns a fresh, unused tree log modification sequence number, even if no new
370 u64
btrfs_get_tree_mod_seq(struct btrfs_fs_info
*fs_info
,
371 struct seq_list
*elem
)
373 tree_mod_log_write_lock(fs_info
);
374 spin_lock(&fs_info
->tree_mod_seq_lock
);
376 elem
->seq
= btrfs_inc_tree_mod_seq(fs_info
);
377 list_add_tail(&elem
->list
, &fs_info
->tree_mod_seq_list
);
379 spin_unlock(&fs_info
->tree_mod_seq_lock
);
380 tree_mod_log_write_unlock(fs_info
);
385 void btrfs_put_tree_mod_seq(struct btrfs_fs_info
*fs_info
,
386 struct seq_list
*elem
)
388 struct rb_root
*tm_root
;
389 struct rb_node
*node
;
390 struct rb_node
*next
;
391 struct seq_list
*cur_elem
;
392 struct tree_mod_elem
*tm
;
393 u64 min_seq
= (u64
)-1;
394 u64 seq_putting
= elem
->seq
;
399 spin_lock(&fs_info
->tree_mod_seq_lock
);
400 list_del(&elem
->list
);
403 list_for_each_entry(cur_elem
, &fs_info
->tree_mod_seq_list
, list
) {
404 if (cur_elem
->seq
< min_seq
) {
405 if (seq_putting
> cur_elem
->seq
) {
407 * blocker with lower sequence number exists, we
408 * cannot remove anything from the log
410 spin_unlock(&fs_info
->tree_mod_seq_lock
);
413 min_seq
= cur_elem
->seq
;
416 spin_unlock(&fs_info
->tree_mod_seq_lock
);
419 * anything that's lower than the lowest existing (read: blocked)
420 * sequence number can be removed from the tree.
422 tree_mod_log_write_lock(fs_info
);
423 tm_root
= &fs_info
->tree_mod_log
;
424 for (node
= rb_first(tm_root
); node
; node
= next
) {
425 next
= rb_next(node
);
426 tm
= container_of(node
, struct tree_mod_elem
, node
);
427 if (tm
->seq
> min_seq
)
429 rb_erase(node
, tm_root
);
432 tree_mod_log_write_unlock(fs_info
);
436 * key order of the log:
437 * node/leaf start address -> sequence
439 * The 'start address' is the logical address of the *new* root node
440 * for root replace operations, or the logical address of the affected
441 * block for all other operations.
443 * Note: must be called with write lock (tree_mod_log_write_lock).
446 __tree_mod_log_insert(struct btrfs_fs_info
*fs_info
, struct tree_mod_elem
*tm
)
448 struct rb_root
*tm_root
;
449 struct rb_node
**new;
450 struct rb_node
*parent
= NULL
;
451 struct tree_mod_elem
*cur
;
455 tm
->seq
= btrfs_inc_tree_mod_seq(fs_info
);
457 tm_root
= &fs_info
->tree_mod_log
;
458 new = &tm_root
->rb_node
;
460 cur
= container_of(*new, struct tree_mod_elem
, node
);
462 if (cur
->logical
< tm
->logical
)
463 new = &((*new)->rb_left
);
464 else if (cur
->logical
> tm
->logical
)
465 new = &((*new)->rb_right
);
466 else if (cur
->seq
< tm
->seq
)
467 new = &((*new)->rb_left
);
468 else if (cur
->seq
> tm
->seq
)
469 new = &((*new)->rb_right
);
474 rb_link_node(&tm
->node
, parent
, new);
475 rb_insert_color(&tm
->node
, tm_root
);
480 * Determines if logging can be omitted. Returns 1 if it can. Otherwise, it
481 * returns zero with the tree_mod_log_lock acquired. The caller must hold
482 * this until all tree mod log insertions are recorded in the rb tree and then
483 * call tree_mod_log_write_unlock() to release.
485 static inline int tree_mod_dont_log(struct btrfs_fs_info
*fs_info
,
486 struct extent_buffer
*eb
) {
488 if (list_empty(&(fs_info
)->tree_mod_seq_list
))
490 if (eb
&& btrfs_header_level(eb
) == 0)
493 tree_mod_log_write_lock(fs_info
);
494 if (list_empty(&(fs_info
)->tree_mod_seq_list
)) {
495 tree_mod_log_write_unlock(fs_info
);
502 /* Similar to tree_mod_dont_log, but doesn't acquire any locks. */
503 static inline int tree_mod_need_log(const struct btrfs_fs_info
*fs_info
,
504 struct extent_buffer
*eb
)
507 if (list_empty(&(fs_info
)->tree_mod_seq_list
))
509 if (eb
&& btrfs_header_level(eb
) == 0)
515 static struct tree_mod_elem
*
516 alloc_tree_mod_elem(struct extent_buffer
*eb
, int slot
,
517 enum mod_log_op op
, gfp_t flags
)
519 struct tree_mod_elem
*tm
;
521 tm
= kzalloc(sizeof(*tm
), flags
);
525 tm
->logical
= eb
->start
;
526 if (op
!= MOD_LOG_KEY_ADD
) {
527 btrfs_node_key(eb
, &tm
->key
, slot
);
528 tm
->blockptr
= btrfs_node_blockptr(eb
, slot
);
532 tm
->generation
= btrfs_node_ptr_generation(eb
, slot
);
533 RB_CLEAR_NODE(&tm
->node
);
539 tree_mod_log_insert_key(struct btrfs_fs_info
*fs_info
,
540 struct extent_buffer
*eb
, int slot
,
541 enum mod_log_op op
, gfp_t flags
)
543 struct tree_mod_elem
*tm
;
546 if (!tree_mod_need_log(fs_info
, eb
))
549 tm
= alloc_tree_mod_elem(eb
, slot
, op
, flags
);
553 if (tree_mod_dont_log(fs_info
, eb
)) {
558 ret
= __tree_mod_log_insert(fs_info
, tm
);
559 tree_mod_log_write_unlock(fs_info
);
567 tree_mod_log_insert_move(struct btrfs_fs_info
*fs_info
,
568 struct extent_buffer
*eb
, int dst_slot
, int src_slot
,
569 int nr_items
, gfp_t flags
)
571 struct tree_mod_elem
*tm
= NULL
;
572 struct tree_mod_elem
**tm_list
= NULL
;
577 if (!tree_mod_need_log(fs_info
, eb
))
580 tm_list
= kcalloc(nr_items
, sizeof(struct tree_mod_elem
*), flags
);
584 tm
= kzalloc(sizeof(*tm
), flags
);
590 tm
->logical
= eb
->start
;
592 tm
->move
.dst_slot
= dst_slot
;
593 tm
->move
.nr_items
= nr_items
;
594 tm
->op
= MOD_LOG_MOVE_KEYS
;
596 for (i
= 0; i
+ dst_slot
< src_slot
&& i
< nr_items
; i
++) {
597 tm_list
[i
] = alloc_tree_mod_elem(eb
, i
+ dst_slot
,
598 MOD_LOG_KEY_REMOVE_WHILE_MOVING
, flags
);
605 if (tree_mod_dont_log(fs_info
, eb
))
610 * When we override something during the move, we log these removals.
611 * This can only happen when we move towards the beginning of the
612 * buffer, i.e. dst_slot < src_slot.
614 for (i
= 0; i
+ dst_slot
< src_slot
&& i
< nr_items
; i
++) {
615 ret
= __tree_mod_log_insert(fs_info
, tm_list
[i
]);
620 ret
= __tree_mod_log_insert(fs_info
, tm
);
623 tree_mod_log_write_unlock(fs_info
);
628 for (i
= 0; i
< nr_items
; i
++) {
629 if (tm_list
[i
] && !RB_EMPTY_NODE(&tm_list
[i
]->node
))
630 rb_erase(&tm_list
[i
]->node
, &fs_info
->tree_mod_log
);
634 tree_mod_log_write_unlock(fs_info
);
642 __tree_mod_log_free_eb(struct btrfs_fs_info
*fs_info
,
643 struct tree_mod_elem
**tm_list
,
649 for (i
= nritems
- 1; i
>= 0; i
--) {
650 ret
= __tree_mod_log_insert(fs_info
, tm_list
[i
]);
652 for (j
= nritems
- 1; j
> i
; j
--)
653 rb_erase(&tm_list
[j
]->node
,
654 &fs_info
->tree_mod_log
);
663 tree_mod_log_insert_root(struct btrfs_fs_info
*fs_info
,
664 struct extent_buffer
*old_root
,
665 struct extent_buffer
*new_root
, gfp_t flags
,
668 struct tree_mod_elem
*tm
= NULL
;
669 struct tree_mod_elem
**tm_list
= NULL
;
674 if (!tree_mod_need_log(fs_info
, NULL
))
677 if (log_removal
&& btrfs_header_level(old_root
) > 0) {
678 nritems
= btrfs_header_nritems(old_root
);
679 tm_list
= kcalloc(nritems
, sizeof(struct tree_mod_elem
*),
685 for (i
= 0; i
< nritems
; i
++) {
686 tm_list
[i
] = alloc_tree_mod_elem(old_root
, i
,
687 MOD_LOG_KEY_REMOVE_WHILE_FREEING
, flags
);
695 tm
= kzalloc(sizeof(*tm
), flags
);
701 tm
->logical
= new_root
->start
;
702 tm
->old_root
.logical
= old_root
->start
;
703 tm
->old_root
.level
= btrfs_header_level(old_root
);
704 tm
->generation
= btrfs_header_generation(old_root
);
705 tm
->op
= MOD_LOG_ROOT_REPLACE
;
707 if (tree_mod_dont_log(fs_info
, NULL
))
711 ret
= __tree_mod_log_free_eb(fs_info
, tm_list
, nritems
);
713 ret
= __tree_mod_log_insert(fs_info
, tm
);
715 tree_mod_log_write_unlock(fs_info
);
724 for (i
= 0; i
< nritems
; i
++)
733 static struct tree_mod_elem
*
734 __tree_mod_log_search(struct btrfs_fs_info
*fs_info
, u64 start
, u64 min_seq
,
737 struct rb_root
*tm_root
;
738 struct rb_node
*node
;
739 struct tree_mod_elem
*cur
= NULL
;
740 struct tree_mod_elem
*found
= NULL
;
742 tree_mod_log_read_lock(fs_info
);
743 tm_root
= &fs_info
->tree_mod_log
;
744 node
= tm_root
->rb_node
;
746 cur
= container_of(node
, struct tree_mod_elem
, node
);
747 if (cur
->logical
< start
) {
748 node
= node
->rb_left
;
749 } else if (cur
->logical
> start
) {
750 node
= node
->rb_right
;
751 } else if (cur
->seq
< min_seq
) {
752 node
= node
->rb_left
;
753 } else if (!smallest
) {
754 /* we want the node with the highest seq */
756 BUG_ON(found
->seq
> cur
->seq
);
758 node
= node
->rb_left
;
759 } else if (cur
->seq
> min_seq
) {
760 /* we want the node with the smallest seq */
762 BUG_ON(found
->seq
< cur
->seq
);
764 node
= node
->rb_right
;
770 tree_mod_log_read_unlock(fs_info
);
776 * this returns the element from the log with the smallest time sequence
777 * value that's in the log (the oldest log item). any element with a time
778 * sequence lower than min_seq will be ignored.
780 static struct tree_mod_elem
*
781 tree_mod_log_search_oldest(struct btrfs_fs_info
*fs_info
, u64 start
,
784 return __tree_mod_log_search(fs_info
, start
, min_seq
, 1);
788 * this returns the element from the log with the largest time sequence
789 * value that's in the log (the most recent log item). any element with
790 * a time sequence lower than min_seq will be ignored.
792 static struct tree_mod_elem
*
793 tree_mod_log_search(struct btrfs_fs_info
*fs_info
, u64 start
, u64 min_seq
)
795 return __tree_mod_log_search(fs_info
, start
, min_seq
, 0);
799 tree_mod_log_eb_copy(struct btrfs_fs_info
*fs_info
, struct extent_buffer
*dst
,
800 struct extent_buffer
*src
, unsigned long dst_offset
,
801 unsigned long src_offset
, int nr_items
)
804 struct tree_mod_elem
**tm_list
= NULL
;
805 struct tree_mod_elem
**tm_list_add
, **tm_list_rem
;
809 if (!tree_mod_need_log(fs_info
, NULL
))
812 if (btrfs_header_level(dst
) == 0 && btrfs_header_level(src
) == 0)
815 tm_list
= kcalloc(nr_items
* 2, sizeof(struct tree_mod_elem
*),
820 tm_list_add
= tm_list
;
821 tm_list_rem
= tm_list
+ nr_items
;
822 for (i
= 0; i
< nr_items
; i
++) {
823 tm_list_rem
[i
] = alloc_tree_mod_elem(src
, i
+ src_offset
,
824 MOD_LOG_KEY_REMOVE
, GFP_NOFS
);
825 if (!tm_list_rem
[i
]) {
830 tm_list_add
[i
] = alloc_tree_mod_elem(dst
, i
+ dst_offset
,
831 MOD_LOG_KEY_ADD
, GFP_NOFS
);
832 if (!tm_list_add
[i
]) {
838 if (tree_mod_dont_log(fs_info
, NULL
))
842 for (i
= 0; i
< nr_items
; i
++) {
843 ret
= __tree_mod_log_insert(fs_info
, tm_list_rem
[i
]);
846 ret
= __tree_mod_log_insert(fs_info
, tm_list_add
[i
]);
851 tree_mod_log_write_unlock(fs_info
);
857 for (i
= 0; i
< nr_items
* 2; i
++) {
858 if (tm_list
[i
] && !RB_EMPTY_NODE(&tm_list
[i
]->node
))
859 rb_erase(&tm_list
[i
]->node
, &fs_info
->tree_mod_log
);
863 tree_mod_log_write_unlock(fs_info
);
870 tree_mod_log_eb_move(struct btrfs_fs_info
*fs_info
, struct extent_buffer
*dst
,
871 int dst_offset
, int src_offset
, int nr_items
)
874 ret
= tree_mod_log_insert_move(fs_info
, dst
, dst_offset
, src_offset
,
880 tree_mod_log_set_node_key(struct btrfs_fs_info
*fs_info
,
881 struct extent_buffer
*eb
, int slot
, int atomic
)
885 ret
= tree_mod_log_insert_key(fs_info
, eb
, slot
,
887 atomic
? GFP_ATOMIC
: GFP_NOFS
);
892 tree_mod_log_free_eb(struct btrfs_fs_info
*fs_info
, struct extent_buffer
*eb
)
894 struct tree_mod_elem
**tm_list
= NULL
;
899 if (btrfs_header_level(eb
) == 0)
902 if (!tree_mod_need_log(fs_info
, NULL
))
905 nritems
= btrfs_header_nritems(eb
);
906 tm_list
= kcalloc(nritems
, sizeof(struct tree_mod_elem
*), GFP_NOFS
);
910 for (i
= 0; i
< nritems
; i
++) {
911 tm_list
[i
] = alloc_tree_mod_elem(eb
, i
,
912 MOD_LOG_KEY_REMOVE_WHILE_FREEING
, GFP_NOFS
);
919 if (tree_mod_dont_log(fs_info
, eb
))
922 ret
= __tree_mod_log_free_eb(fs_info
, tm_list
, nritems
);
923 tree_mod_log_write_unlock(fs_info
);
931 for (i
= 0; i
< nritems
; i
++)
939 tree_mod_log_set_root_pointer(struct btrfs_root
*root
,
940 struct extent_buffer
*new_root_node
,
944 ret
= tree_mod_log_insert_root(root
->fs_info
, root
->node
,
945 new_root_node
, GFP_NOFS
, log_removal
);
950 * check if the tree block can be shared by multiple trees
952 int btrfs_block_can_be_shared(struct btrfs_root
*root
,
953 struct extent_buffer
*buf
)
956 * Tree blocks not in reference counted trees and tree roots
957 * are never shared. If a block was allocated after the last
958 * snapshot and the block was not allocated by tree relocation,
959 * we know the block is not shared.
961 if (test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
962 buf
!= root
->node
&& buf
!= root
->commit_root
&&
963 (btrfs_header_generation(buf
) <=
964 btrfs_root_last_snapshot(&root
->root_item
) ||
965 btrfs_header_flag(buf
, BTRFS_HEADER_FLAG_RELOC
)))
967 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
968 if (test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
969 btrfs_header_backref_rev(buf
) < BTRFS_MIXED_BACKREF_REV
)
975 static noinline
int update_ref_for_cow(struct btrfs_trans_handle
*trans
,
976 struct btrfs_root
*root
,
977 struct extent_buffer
*buf
,
978 struct extent_buffer
*cow
,
988 * Backrefs update rules:
990 * Always use full backrefs for extent pointers in tree block
991 * allocated by tree relocation.
993 * If a shared tree block is no longer referenced by its owner
994 * tree (btrfs_header_owner(buf) == root->root_key.objectid),
995 * use full backrefs for extent pointers in tree block.
997 * If a tree block is been relocating
998 * (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID),
999 * use full backrefs for extent pointers in tree block.
1000 * The reason for this is some operations (such as drop tree)
1001 * are only allowed for blocks use full backrefs.
1004 if (btrfs_block_can_be_shared(root
, buf
)) {
1005 ret
= btrfs_lookup_extent_info(trans
, root
, buf
->start
,
1006 btrfs_header_level(buf
), 1,
1012 btrfs_handle_fs_error(root
->fs_info
, ret
, NULL
);
1017 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
||
1018 btrfs_header_backref_rev(buf
) < BTRFS_MIXED_BACKREF_REV
)
1019 flags
= BTRFS_BLOCK_FLAG_FULL_BACKREF
;
1024 owner
= btrfs_header_owner(buf
);
1025 BUG_ON(owner
== BTRFS_TREE_RELOC_OBJECTID
&&
1026 !(flags
& BTRFS_BLOCK_FLAG_FULL_BACKREF
));
1029 if ((owner
== root
->root_key
.objectid
||
1030 root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
) &&
1031 !(flags
& BTRFS_BLOCK_FLAG_FULL_BACKREF
)) {
1032 ret
= btrfs_inc_ref(trans
, root
, buf
, 1);
1033 BUG_ON(ret
); /* -ENOMEM */
1035 if (root
->root_key
.objectid
==
1036 BTRFS_TREE_RELOC_OBJECTID
) {
1037 ret
= btrfs_dec_ref(trans
, root
, buf
, 0);
1038 BUG_ON(ret
); /* -ENOMEM */
1039 ret
= btrfs_inc_ref(trans
, root
, cow
, 1);
1040 BUG_ON(ret
); /* -ENOMEM */
1042 new_flags
|= BTRFS_BLOCK_FLAG_FULL_BACKREF
;
1045 if (root
->root_key
.objectid
==
1046 BTRFS_TREE_RELOC_OBJECTID
)
1047 ret
= btrfs_inc_ref(trans
, root
, cow
, 1);
1049 ret
= btrfs_inc_ref(trans
, root
, cow
, 0);
1050 BUG_ON(ret
); /* -ENOMEM */
1052 if (new_flags
!= 0) {
1053 int level
= btrfs_header_level(buf
);
1055 ret
= btrfs_set_disk_extent_flags(trans
, root
,
1058 new_flags
, level
, 0);
1063 if (flags
& BTRFS_BLOCK_FLAG_FULL_BACKREF
) {
1064 if (root
->root_key
.objectid
==
1065 BTRFS_TREE_RELOC_OBJECTID
)
1066 ret
= btrfs_inc_ref(trans
, root
, cow
, 1);
1068 ret
= btrfs_inc_ref(trans
, root
, cow
, 0);
1069 BUG_ON(ret
); /* -ENOMEM */
1070 ret
= btrfs_dec_ref(trans
, root
, buf
, 1);
1071 BUG_ON(ret
); /* -ENOMEM */
1073 clean_tree_block(trans
, root
->fs_info
, buf
);
1080 * does the dirty work in cow of a single block. The parent block (if
1081 * supplied) is updated to point to the new cow copy. The new buffer is marked
1082 * dirty and returned locked. If you modify the block it needs to be marked
1085 * search_start -- an allocation hint for the new block
1087 * empty_size -- a hint that you plan on doing more cow. This is the size in
1088 * bytes the allocator should try to find free next to the block it returns.
1089 * This is just a hint and may be ignored by the allocator.
1091 static noinline
int __btrfs_cow_block(struct btrfs_trans_handle
*trans
,
1092 struct btrfs_root
*root
,
1093 struct extent_buffer
*buf
,
1094 struct extent_buffer
*parent
, int parent_slot
,
1095 struct extent_buffer
**cow_ret
,
1096 u64 search_start
, u64 empty_size
)
1098 struct btrfs_disk_key disk_key
;
1099 struct extent_buffer
*cow
;
1102 int unlock_orig
= 0;
1105 if (*cow_ret
== buf
)
1108 btrfs_assert_tree_locked(buf
);
1110 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
1111 trans
->transid
!= root
->fs_info
->running_transaction
->transid
);
1112 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
1113 trans
->transid
!= root
->last_trans
);
1115 level
= btrfs_header_level(buf
);
1118 btrfs_item_key(buf
, &disk_key
, 0);
1120 btrfs_node_key(buf
, &disk_key
, 0);
1122 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
) {
1124 parent_start
= parent
->start
;
1130 cow
= btrfs_alloc_tree_block(trans
, root
, parent_start
,
1131 root
->root_key
.objectid
, &disk_key
, level
,
1132 search_start
, empty_size
);
1134 return PTR_ERR(cow
);
1136 /* cow is set to blocking by btrfs_init_new_buffer */
1138 copy_extent_buffer(cow
, buf
, 0, 0, cow
->len
);
1139 btrfs_set_header_bytenr(cow
, cow
->start
);
1140 btrfs_set_header_generation(cow
, trans
->transid
);
1141 btrfs_set_header_backref_rev(cow
, BTRFS_MIXED_BACKREF_REV
);
1142 btrfs_clear_header_flag(cow
, BTRFS_HEADER_FLAG_WRITTEN
|
1143 BTRFS_HEADER_FLAG_RELOC
);
1144 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
)
1145 btrfs_set_header_flag(cow
, BTRFS_HEADER_FLAG_RELOC
);
1147 btrfs_set_header_owner(cow
, root
->root_key
.objectid
);
1149 write_extent_buffer(cow
, root
->fs_info
->fsid
, btrfs_header_fsid(),
1152 ret
= update_ref_for_cow(trans
, root
, buf
, cow
, &last_ref
);
1154 btrfs_abort_transaction(trans
, ret
);
1158 if (test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
)) {
1159 ret
= btrfs_reloc_cow_block(trans
, root
, buf
, cow
);
1161 btrfs_abort_transaction(trans
, ret
);
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
, 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
1232 * replacement operation (if it is replaced at all). this has
1233 * the logical address of the *new* root, making it the very
1234 * first operation that's logged for this root.
1237 tm
= tree_mod_log_search_oldest(fs_info
, root_logical
,
1242 * if there are no tree operation for the oldest root, we simply
1243 * return it. this should only happen if that (old) root is at
1250 * if there's an operation that's not a root replacement, we
1251 * found the oldest version of our root. normally, we'll find a
1252 * MOD_LOG_KEY_REMOVE_WHILE_FREEING operation here.
1254 if (tm
->op
!= MOD_LOG_ROOT_REPLACE
)
1258 root_logical
= tm
->old_root
.logical
;
1262 /* if there's no old root to return, return what we found instead */
1270 * tm is a pointer to the first operation to rewind within eb. then, all
1271 * previous operations will be rewound (until we reach something older than
1275 __tree_mod_log_rewind(struct btrfs_fs_info
*fs_info
, struct extent_buffer
*eb
,
1276 u64 time_seq
, struct tree_mod_elem
*first_tm
)
1279 struct rb_node
*next
;
1280 struct tree_mod_elem
*tm
= first_tm
;
1281 unsigned long o_dst
;
1282 unsigned long o_src
;
1283 unsigned long p_size
= sizeof(struct btrfs_key_ptr
);
1285 n
= btrfs_header_nritems(eb
);
1286 tree_mod_log_read_lock(fs_info
);
1287 while (tm
&& tm
->seq
>= time_seq
) {
1289 * all the operations are recorded with the operator used for
1290 * the modification. as we're going backwards, we do the
1291 * opposite of each operation here.
1294 case MOD_LOG_KEY_REMOVE_WHILE_FREEING
:
1295 BUG_ON(tm
->slot
< n
);
1297 case MOD_LOG_KEY_REMOVE_WHILE_MOVING
:
1298 case MOD_LOG_KEY_REMOVE
:
1299 btrfs_set_node_key(eb
, &tm
->key
, tm
->slot
);
1300 btrfs_set_node_blockptr(eb
, tm
->slot
, tm
->blockptr
);
1301 btrfs_set_node_ptr_generation(eb
, tm
->slot
,
1305 case MOD_LOG_KEY_REPLACE
:
1306 BUG_ON(tm
->slot
>= n
);
1307 btrfs_set_node_key(eb
, &tm
->key
, tm
->slot
);
1308 btrfs_set_node_blockptr(eb
, tm
->slot
, tm
->blockptr
);
1309 btrfs_set_node_ptr_generation(eb
, tm
->slot
,
1312 case MOD_LOG_KEY_ADD
:
1313 /* if a move operation is needed it's in the log */
1316 case MOD_LOG_MOVE_KEYS
:
1317 o_dst
= btrfs_node_key_ptr_offset(tm
->slot
);
1318 o_src
= btrfs_node_key_ptr_offset(tm
->move
.dst_slot
);
1319 memmove_extent_buffer(eb
, o_dst
, o_src
,
1320 tm
->move
.nr_items
* p_size
);
1322 case MOD_LOG_ROOT_REPLACE
:
1324 * this operation is special. for roots, this must be
1325 * handled explicitly before rewinding.
1326 * for non-roots, this operation may exist if the node
1327 * was a root: root A -> child B; then A gets empty and
1328 * B is promoted to the new root. in the mod log, we'll
1329 * have a root-replace operation for B, a tree block
1330 * that is no root. we simply ignore that operation.
1334 next
= rb_next(&tm
->node
);
1337 tm
= container_of(next
, struct tree_mod_elem
, node
);
1338 if (tm
->logical
!= first_tm
->logical
)
1341 tree_mod_log_read_unlock(fs_info
);
1342 btrfs_set_header_nritems(eb
, n
);
1346 * Called with eb read locked. If the buffer cannot be rewound, the same buffer
1347 * is returned. If rewind operations happen, a fresh buffer is returned. The
1348 * returned buffer is always read-locked. If the returned buffer is not the
1349 * input buffer, the lock on the input buffer is released and the input buffer
1350 * is freed (its refcount is decremented).
1352 static struct extent_buffer
*
1353 tree_mod_log_rewind(struct btrfs_fs_info
*fs_info
, struct btrfs_path
*path
,
1354 struct extent_buffer
*eb
, u64 time_seq
)
1356 struct extent_buffer
*eb_rewin
;
1357 struct tree_mod_elem
*tm
;
1362 if (btrfs_header_level(eb
) == 0)
1365 tm
= tree_mod_log_search(fs_info
, eb
->start
, time_seq
);
1369 btrfs_set_path_blocking(path
);
1370 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1372 if (tm
->op
== MOD_LOG_KEY_REMOVE_WHILE_FREEING
) {
1373 BUG_ON(tm
->slot
!= 0);
1374 eb_rewin
= alloc_dummy_extent_buffer(fs_info
, eb
->start
,
1377 btrfs_tree_read_unlock_blocking(eb
);
1378 free_extent_buffer(eb
);
1381 btrfs_set_header_bytenr(eb_rewin
, eb
->start
);
1382 btrfs_set_header_backref_rev(eb_rewin
,
1383 btrfs_header_backref_rev(eb
));
1384 btrfs_set_header_owner(eb_rewin
, btrfs_header_owner(eb
));
1385 btrfs_set_header_level(eb_rewin
, btrfs_header_level(eb
));
1387 eb_rewin
= btrfs_clone_extent_buffer(eb
);
1389 btrfs_tree_read_unlock_blocking(eb
);
1390 free_extent_buffer(eb
);
1395 btrfs_clear_path_blocking(path
, NULL
, BTRFS_READ_LOCK
);
1396 btrfs_tree_read_unlock_blocking(eb
);
1397 free_extent_buffer(eb
);
1399 extent_buffer_get(eb_rewin
);
1400 btrfs_tree_read_lock(eb_rewin
);
1401 __tree_mod_log_rewind(fs_info
, eb_rewin
, time_seq
, tm
);
1402 WARN_ON(btrfs_header_nritems(eb_rewin
) >
1403 BTRFS_NODEPTRS_PER_BLOCK(fs_info
->tree_root
));
1409 * get_old_root() rewinds the state of @root's root node to the given @time_seq
1410 * value. If there are no changes, the current root->root_node is returned. If
1411 * anything changed in between, there's a fresh buffer allocated on which the
1412 * rewind operations are done. In any case, the returned buffer is read locked.
1413 * Returns NULL on error (with no locks held).
1415 static inline struct extent_buffer
*
1416 get_old_root(struct btrfs_root
*root
, u64 time_seq
)
1418 struct tree_mod_elem
*tm
;
1419 struct extent_buffer
*eb
= NULL
;
1420 struct extent_buffer
*eb_root
;
1421 struct extent_buffer
*old
;
1422 struct tree_mod_root
*old_root
= NULL
;
1423 u64 old_generation
= 0;
1426 eb_root
= btrfs_read_lock_root_node(root
);
1427 tm
= __tree_mod_log_oldest_root(root
->fs_info
, eb_root
, time_seq
);
1431 if (tm
->op
== MOD_LOG_ROOT_REPLACE
) {
1432 old_root
= &tm
->old_root
;
1433 old_generation
= tm
->generation
;
1434 logical
= old_root
->logical
;
1436 logical
= eb_root
->start
;
1439 tm
= tree_mod_log_search(root
->fs_info
, logical
, time_seq
);
1440 if (old_root
&& tm
&& tm
->op
!= MOD_LOG_KEY_REMOVE_WHILE_FREEING
) {
1441 btrfs_tree_read_unlock(eb_root
);
1442 free_extent_buffer(eb_root
);
1443 old
= read_tree_block(root
, logical
, 0);
1444 if (WARN_ON(IS_ERR(old
) || !extent_buffer_uptodate(old
))) {
1446 free_extent_buffer(old
);
1447 btrfs_warn(root
->fs_info
,
1448 "failed to read tree block %llu from get_old_root", logical
);
1450 eb
= btrfs_clone_extent_buffer(old
);
1451 free_extent_buffer(old
);
1453 } else if (old_root
) {
1454 btrfs_tree_read_unlock(eb_root
);
1455 free_extent_buffer(eb_root
);
1456 eb
= alloc_dummy_extent_buffer(root
->fs_info
, logical
,
1459 btrfs_set_lock_blocking_rw(eb_root
, BTRFS_READ_LOCK
);
1460 eb
= btrfs_clone_extent_buffer(eb_root
);
1461 btrfs_tree_read_unlock_blocking(eb_root
);
1462 free_extent_buffer(eb_root
);
1467 extent_buffer_get(eb
);
1468 btrfs_tree_read_lock(eb
);
1470 btrfs_set_header_bytenr(eb
, eb
->start
);
1471 btrfs_set_header_backref_rev(eb
, BTRFS_MIXED_BACKREF_REV
);
1472 btrfs_set_header_owner(eb
, btrfs_header_owner(eb_root
));
1473 btrfs_set_header_level(eb
, old_root
->level
);
1474 btrfs_set_header_generation(eb
, old_generation
);
1477 __tree_mod_log_rewind(root
->fs_info
, eb
, time_seq
, tm
);
1479 WARN_ON(btrfs_header_level(eb
) != 0);
1480 WARN_ON(btrfs_header_nritems(eb
) > BTRFS_NODEPTRS_PER_BLOCK(root
));
1485 int btrfs_old_root_level(struct btrfs_root
*root
, u64 time_seq
)
1487 struct tree_mod_elem
*tm
;
1489 struct extent_buffer
*eb_root
= btrfs_root_node(root
);
1491 tm
= __tree_mod_log_oldest_root(root
->fs_info
, eb_root
, time_seq
);
1492 if (tm
&& tm
->op
== MOD_LOG_ROOT_REPLACE
) {
1493 level
= tm
->old_root
.level
;
1495 level
= btrfs_header_level(eb_root
);
1497 free_extent_buffer(eb_root
);
1502 static inline int should_cow_block(struct btrfs_trans_handle
*trans
,
1503 struct btrfs_root
*root
,
1504 struct extent_buffer
*buf
)
1506 if (btrfs_is_testing(root
->fs_info
))
1509 /* ensure we can see the force_cow */
1513 * We do not need to cow a block if
1514 * 1) this block is not created or changed in this transaction;
1515 * 2) this block does not belong to TREE_RELOC tree;
1516 * 3) the root is not forced COW.
1518 * What is forced COW:
1519 * when we create snapshot during committing the transaction,
1520 * after we've finished coping src root, we must COW the shared
1521 * block to ensure the metadata consistency.
1523 if (btrfs_header_generation(buf
) == trans
->transid
&&
1524 !btrfs_header_flag(buf
, BTRFS_HEADER_FLAG_WRITTEN
) &&
1525 !(root
->root_key
.objectid
!= BTRFS_TREE_RELOC_OBJECTID
&&
1526 btrfs_header_flag(buf
, BTRFS_HEADER_FLAG_RELOC
)) &&
1527 !test_bit(BTRFS_ROOT_FORCE_COW
, &root
->state
))
1533 * cows a single block, see __btrfs_cow_block for the real work.
1534 * This version of it has extra checks so that a block isn't COWed more than
1535 * once per transaction, as long as it hasn't been written yet
1537 noinline
int btrfs_cow_block(struct btrfs_trans_handle
*trans
,
1538 struct btrfs_root
*root
, struct extent_buffer
*buf
,
1539 struct extent_buffer
*parent
, int parent_slot
,
1540 struct extent_buffer
**cow_ret
)
1545 if (trans
->transaction
!= root
->fs_info
->running_transaction
)
1546 WARN(1, KERN_CRIT
"trans %llu running %llu\n",
1548 root
->fs_info
->running_transaction
->transid
);
1550 if (trans
->transid
!= root
->fs_info
->generation
)
1551 WARN(1, KERN_CRIT
"trans %llu running %llu\n",
1552 trans
->transid
, root
->fs_info
->generation
);
1554 if (!should_cow_block(trans
, root
, buf
)) {
1555 trans
->dirty
= true;
1560 search_start
= buf
->start
& ~((u64
)SZ_1G
- 1);
1563 btrfs_set_lock_blocking(parent
);
1564 btrfs_set_lock_blocking(buf
);
1566 ret
= __btrfs_cow_block(trans
, root
, buf
, parent
,
1567 parent_slot
, cow_ret
, search_start
, 0);
1569 trace_btrfs_cow_block(root
, buf
, *cow_ret
);
1575 * helper function for defrag to decide if two blocks pointed to by a
1576 * node are actually close by
1578 static int close_blocks(u64 blocknr
, u64 other
, u32 blocksize
)
1580 if (blocknr
< other
&& other
- (blocknr
+ blocksize
) < 32768)
1582 if (blocknr
> other
&& blocknr
- (other
+ blocksize
) < 32768)
1588 * compare two keys in a memcmp fashion
1590 static int comp_keys(struct btrfs_disk_key
*disk
, struct btrfs_key
*k2
)
1592 struct btrfs_key k1
;
1594 btrfs_disk_key_to_cpu(&k1
, disk
);
1596 return btrfs_comp_cpu_keys(&k1
, k2
);
1600 * same as comp_keys only with two btrfs_key's
1602 int btrfs_comp_cpu_keys(struct btrfs_key
*k1
, struct btrfs_key
*k2
)
1604 if (k1
->objectid
> k2
->objectid
)
1606 if (k1
->objectid
< k2
->objectid
)
1608 if (k1
->type
> k2
->type
)
1610 if (k1
->type
< k2
->type
)
1612 if (k1
->offset
> k2
->offset
)
1614 if (k1
->offset
< k2
->offset
)
1620 * this is used by the defrag code to go through all the
1621 * leaves pointed to by a node and reallocate them so that
1622 * disk order is close to key order
1624 int btrfs_realloc_node(struct btrfs_trans_handle
*trans
,
1625 struct btrfs_root
*root
, struct extent_buffer
*parent
,
1626 int start_slot
, u64
*last_ret
,
1627 struct btrfs_key
*progress
)
1629 struct extent_buffer
*cur
;
1632 u64 search_start
= *last_ret
;
1642 int progress_passed
= 0;
1643 struct btrfs_disk_key disk_key
;
1645 parent_level
= btrfs_header_level(parent
);
1647 WARN_ON(trans
->transaction
!= root
->fs_info
->running_transaction
);
1648 WARN_ON(trans
->transid
!= root
->fs_info
->generation
);
1650 parent_nritems
= btrfs_header_nritems(parent
);
1651 blocksize
= root
->nodesize
;
1652 end_slot
= parent_nritems
- 1;
1654 if (parent_nritems
<= 1)
1657 btrfs_set_lock_blocking(parent
);
1659 for (i
= start_slot
; i
<= end_slot
; i
++) {
1662 btrfs_node_key(parent
, &disk_key
, i
);
1663 if (!progress_passed
&& comp_keys(&disk_key
, progress
) < 0)
1666 progress_passed
= 1;
1667 blocknr
= btrfs_node_blockptr(parent
, i
);
1668 gen
= btrfs_node_ptr_generation(parent
, i
);
1669 if (last_block
== 0)
1670 last_block
= blocknr
;
1673 other
= btrfs_node_blockptr(parent
, i
- 1);
1674 close
= close_blocks(blocknr
, other
, blocksize
);
1676 if (!close
&& i
< end_slot
) {
1677 other
= btrfs_node_blockptr(parent
, i
+ 1);
1678 close
= close_blocks(blocknr
, other
, blocksize
);
1681 last_block
= blocknr
;
1685 cur
= btrfs_find_tree_block(root
->fs_info
, blocknr
);
1687 uptodate
= btrfs_buffer_uptodate(cur
, gen
, 0);
1690 if (!cur
|| !uptodate
) {
1692 cur
= read_tree_block(root
, blocknr
, gen
);
1694 return PTR_ERR(cur
);
1695 } else if (!extent_buffer_uptodate(cur
)) {
1696 free_extent_buffer(cur
);
1699 } else if (!uptodate
) {
1700 err
= btrfs_read_buffer(cur
, gen
);
1702 free_extent_buffer(cur
);
1707 if (search_start
== 0)
1708 search_start
= last_block
;
1710 btrfs_tree_lock(cur
);
1711 btrfs_set_lock_blocking(cur
);
1712 err
= __btrfs_cow_block(trans
, root
, cur
, parent
, i
,
1715 (end_slot
- i
) * blocksize
));
1717 btrfs_tree_unlock(cur
);
1718 free_extent_buffer(cur
);
1721 search_start
= cur
->start
;
1722 last_block
= cur
->start
;
1723 *last_ret
= search_start
;
1724 btrfs_tree_unlock(cur
);
1725 free_extent_buffer(cur
);
1731 * The leaf data grows from end-to-front in the node.
1732 * this returns the address of the start of the last item,
1733 * which is the stop of the leaf data stack
1735 static inline unsigned int leaf_data_end(struct btrfs_root
*root
,
1736 struct extent_buffer
*leaf
)
1738 u32 nr
= btrfs_header_nritems(leaf
);
1740 return BTRFS_LEAF_DATA_SIZE(root
);
1741 return btrfs_item_offset_nr(leaf
, nr
- 1);
1746 * search for key in the extent_buffer. The items start at offset p,
1747 * and they are item_size apart. There are 'max' items in p.
1749 * the slot in the array is returned via slot, and it points to
1750 * the place where you would insert key if it is not found in
1753 * slot may point to max if the key is bigger than all of the keys
1755 static noinline
int generic_bin_search(struct extent_buffer
*eb
,
1757 int item_size
, struct btrfs_key
*key
,
1764 struct btrfs_disk_key
*tmp
= NULL
;
1765 struct btrfs_disk_key unaligned
;
1766 unsigned long offset
;
1768 unsigned long map_start
= 0;
1769 unsigned long map_len
= 0;
1773 btrfs_err(eb
->fs_info
,
1774 "%s: low (%d) > high (%d) eb %llu owner %llu level %d",
1775 __func__
, low
, high
, eb
->start
,
1776 btrfs_header_owner(eb
), btrfs_header_level(eb
));
1780 while (low
< high
) {
1781 mid
= (low
+ high
) / 2;
1782 offset
= p
+ mid
* item_size
;
1784 if (!kaddr
|| offset
< map_start
||
1785 (offset
+ sizeof(struct btrfs_disk_key
)) >
1786 map_start
+ map_len
) {
1788 err
= map_private_extent_buffer(eb
, offset
,
1789 sizeof(struct btrfs_disk_key
),
1790 &kaddr
, &map_start
, &map_len
);
1793 tmp
= (struct btrfs_disk_key
*)(kaddr
+ offset
-
1795 } else if (err
== 1) {
1796 read_extent_buffer(eb
, &unaligned
,
1797 offset
, sizeof(unaligned
));
1804 tmp
= (struct btrfs_disk_key
*)(kaddr
+ offset
-
1807 ret
= comp_keys(tmp
, key
);
1823 * simple bin_search frontend that does the right thing for
1826 static int bin_search(struct extent_buffer
*eb
, struct btrfs_key
*key
,
1827 int level
, int *slot
)
1830 return generic_bin_search(eb
,
1831 offsetof(struct btrfs_leaf
, items
),
1832 sizeof(struct btrfs_item
),
1833 key
, btrfs_header_nritems(eb
),
1836 return generic_bin_search(eb
,
1837 offsetof(struct btrfs_node
, ptrs
),
1838 sizeof(struct btrfs_key_ptr
),
1839 key
, btrfs_header_nritems(eb
),
1843 int btrfs_bin_search(struct extent_buffer
*eb
, struct btrfs_key
*key
,
1844 int level
, int *slot
)
1846 return bin_search(eb
, key
, level
, slot
);
1849 static void root_add_used(struct btrfs_root
*root
, u32 size
)
1851 spin_lock(&root
->accounting_lock
);
1852 btrfs_set_root_used(&root
->root_item
,
1853 btrfs_root_used(&root
->root_item
) + size
);
1854 spin_unlock(&root
->accounting_lock
);
1857 static void root_sub_used(struct btrfs_root
*root
, u32 size
)
1859 spin_lock(&root
->accounting_lock
);
1860 btrfs_set_root_used(&root
->root_item
,
1861 btrfs_root_used(&root
->root_item
) - size
);
1862 spin_unlock(&root
->accounting_lock
);
1865 /* given a node and slot number, this reads the blocks it points to. The
1866 * extent buffer is returned with a reference taken (but unlocked).
1868 static noinline
struct extent_buffer
*read_node_slot(struct btrfs_root
*root
,
1869 struct extent_buffer
*parent
, int slot
)
1871 int level
= btrfs_header_level(parent
);
1872 struct extent_buffer
*eb
;
1874 if (slot
< 0 || slot
>= btrfs_header_nritems(parent
))
1875 return ERR_PTR(-ENOENT
);
1879 eb
= read_tree_block(root
, btrfs_node_blockptr(parent
, slot
),
1880 btrfs_node_ptr_generation(parent
, slot
));
1881 if (!IS_ERR(eb
) && !extent_buffer_uptodate(eb
)) {
1882 free_extent_buffer(eb
);
1890 * node level balancing, used to make sure nodes are in proper order for
1891 * item deletion. We balance from the top down, so we have to make sure
1892 * that a deletion won't leave an node completely empty later on.
1894 static noinline
int balance_level(struct btrfs_trans_handle
*trans
,
1895 struct btrfs_root
*root
,
1896 struct btrfs_path
*path
, int level
)
1898 struct extent_buffer
*right
= NULL
;
1899 struct extent_buffer
*mid
;
1900 struct extent_buffer
*left
= NULL
;
1901 struct extent_buffer
*parent
= NULL
;
1905 int orig_slot
= path
->slots
[level
];
1911 mid
= path
->nodes
[level
];
1913 WARN_ON(path
->locks
[level
] != BTRFS_WRITE_LOCK
&&
1914 path
->locks
[level
] != BTRFS_WRITE_LOCK_BLOCKING
);
1915 WARN_ON(btrfs_header_generation(mid
) != trans
->transid
);
1917 orig_ptr
= btrfs_node_blockptr(mid
, orig_slot
);
1919 if (level
< BTRFS_MAX_LEVEL
- 1) {
1920 parent
= path
->nodes
[level
+ 1];
1921 pslot
= path
->slots
[level
+ 1];
1925 * deal with the case where there is only one pointer in the root
1926 * by promoting the node below to a root
1929 struct extent_buffer
*child
;
1931 if (btrfs_header_nritems(mid
) != 1)
1934 /* promote the child to a root */
1935 child
= read_node_slot(root
, mid
, 0);
1936 if (IS_ERR(child
)) {
1937 ret
= PTR_ERR(child
);
1938 btrfs_handle_fs_error(root
->fs_info
, ret
, NULL
);
1942 btrfs_tree_lock(child
);
1943 btrfs_set_lock_blocking(child
);
1944 ret
= btrfs_cow_block(trans
, root
, child
, mid
, 0, &child
);
1946 btrfs_tree_unlock(child
);
1947 free_extent_buffer(child
);
1951 tree_mod_log_set_root_pointer(root
, child
, 1);
1952 rcu_assign_pointer(root
->node
, child
);
1954 add_root_to_dirty_list(root
);
1955 btrfs_tree_unlock(child
);
1957 path
->locks
[level
] = 0;
1958 path
->nodes
[level
] = NULL
;
1959 clean_tree_block(trans
, root
->fs_info
, mid
);
1960 btrfs_tree_unlock(mid
);
1961 /* once for the path */
1962 free_extent_buffer(mid
);
1964 root_sub_used(root
, mid
->len
);
1965 btrfs_free_tree_block(trans
, root
, mid
, 0, 1);
1966 /* once for the root ptr */
1967 free_extent_buffer_stale(mid
);
1970 if (btrfs_header_nritems(mid
) >
1971 BTRFS_NODEPTRS_PER_BLOCK(root
) / 4)
1974 left
= read_node_slot(root
, parent
, pslot
- 1);
1979 btrfs_tree_lock(left
);
1980 btrfs_set_lock_blocking(left
);
1981 wret
= btrfs_cow_block(trans
, root
, left
,
1982 parent
, pslot
- 1, &left
);
1989 right
= read_node_slot(root
, parent
, pslot
+ 1);
1994 btrfs_tree_lock(right
);
1995 btrfs_set_lock_blocking(right
);
1996 wret
= btrfs_cow_block(trans
, root
, right
,
1997 parent
, pslot
+ 1, &right
);
2004 /* first, try to make some room in the middle buffer */
2006 orig_slot
+= btrfs_header_nritems(left
);
2007 wret
= push_node_left(trans
, root
, left
, mid
, 1);
2013 * then try to empty the right most buffer into the middle
2016 wret
= push_node_left(trans
, root
, mid
, right
, 1);
2017 if (wret
< 0 && wret
!= -ENOSPC
)
2019 if (btrfs_header_nritems(right
) == 0) {
2020 clean_tree_block(trans
, root
->fs_info
, right
);
2021 btrfs_tree_unlock(right
);
2022 del_ptr(root
, path
, level
+ 1, pslot
+ 1);
2023 root_sub_used(root
, right
->len
);
2024 btrfs_free_tree_block(trans
, root
, right
, 0, 1);
2025 free_extent_buffer_stale(right
);
2028 struct btrfs_disk_key right_key
;
2029 btrfs_node_key(right
, &right_key
, 0);
2030 tree_mod_log_set_node_key(root
->fs_info
, parent
,
2032 btrfs_set_node_key(parent
, &right_key
, pslot
+ 1);
2033 btrfs_mark_buffer_dirty(parent
);
2036 if (btrfs_header_nritems(mid
) == 1) {
2038 * we're not allowed to leave a node with one item in the
2039 * tree during a delete. A deletion from lower in the tree
2040 * could try to delete the only pointer in this node.
2041 * So, pull some keys from the left.
2042 * There has to be a left pointer at this point because
2043 * otherwise we would have pulled some pointers from the
2048 btrfs_handle_fs_error(root
->fs_info
, ret
, NULL
);
2051 wret
= balance_node_right(trans
, root
, mid
, left
);
2057 wret
= push_node_left(trans
, root
, left
, mid
, 1);
2063 if (btrfs_header_nritems(mid
) == 0) {
2064 clean_tree_block(trans
, root
->fs_info
, mid
);
2065 btrfs_tree_unlock(mid
);
2066 del_ptr(root
, path
, level
+ 1, pslot
);
2067 root_sub_used(root
, mid
->len
);
2068 btrfs_free_tree_block(trans
, root
, mid
, 0, 1);
2069 free_extent_buffer_stale(mid
);
2072 /* update the parent key to reflect our changes */
2073 struct btrfs_disk_key mid_key
;
2074 btrfs_node_key(mid
, &mid_key
, 0);
2075 tree_mod_log_set_node_key(root
->fs_info
, parent
,
2077 btrfs_set_node_key(parent
, &mid_key
, pslot
);
2078 btrfs_mark_buffer_dirty(parent
);
2081 /* update the path */
2083 if (btrfs_header_nritems(left
) > orig_slot
) {
2084 extent_buffer_get(left
);
2085 /* left was locked after cow */
2086 path
->nodes
[level
] = left
;
2087 path
->slots
[level
+ 1] -= 1;
2088 path
->slots
[level
] = orig_slot
;
2090 btrfs_tree_unlock(mid
);
2091 free_extent_buffer(mid
);
2094 orig_slot
-= btrfs_header_nritems(left
);
2095 path
->slots
[level
] = orig_slot
;
2098 /* double check we haven't messed things up */
2100 btrfs_node_blockptr(path
->nodes
[level
], path
->slots
[level
]))
2104 btrfs_tree_unlock(right
);
2105 free_extent_buffer(right
);
2108 if (path
->nodes
[level
] != left
)
2109 btrfs_tree_unlock(left
);
2110 free_extent_buffer(left
);
2115 /* Node balancing for insertion. Here we only split or push nodes around
2116 * when they are completely full. This is also done top down, so we
2117 * have to be pessimistic.
2119 static noinline
int push_nodes_for_insert(struct btrfs_trans_handle
*trans
,
2120 struct btrfs_root
*root
,
2121 struct btrfs_path
*path
, int level
)
2123 struct extent_buffer
*right
= NULL
;
2124 struct extent_buffer
*mid
;
2125 struct extent_buffer
*left
= NULL
;
2126 struct extent_buffer
*parent
= NULL
;
2130 int orig_slot
= path
->slots
[level
];
2135 mid
= path
->nodes
[level
];
2136 WARN_ON(btrfs_header_generation(mid
) != trans
->transid
);
2138 if (level
< BTRFS_MAX_LEVEL
- 1) {
2139 parent
= path
->nodes
[level
+ 1];
2140 pslot
= path
->slots
[level
+ 1];
2146 left
= read_node_slot(root
, parent
, pslot
- 1);
2150 /* first, try to make some room in the middle buffer */
2154 btrfs_tree_lock(left
);
2155 btrfs_set_lock_blocking(left
);
2157 left_nr
= btrfs_header_nritems(left
);
2158 if (left_nr
>= BTRFS_NODEPTRS_PER_BLOCK(root
) - 1) {
2161 ret
= btrfs_cow_block(trans
, root
, left
, parent
,
2166 wret
= push_node_left(trans
, root
,
2173 struct btrfs_disk_key disk_key
;
2174 orig_slot
+= left_nr
;
2175 btrfs_node_key(mid
, &disk_key
, 0);
2176 tree_mod_log_set_node_key(root
->fs_info
, parent
,
2178 btrfs_set_node_key(parent
, &disk_key
, pslot
);
2179 btrfs_mark_buffer_dirty(parent
);
2180 if (btrfs_header_nritems(left
) > orig_slot
) {
2181 path
->nodes
[level
] = left
;
2182 path
->slots
[level
+ 1] -= 1;
2183 path
->slots
[level
] = orig_slot
;
2184 btrfs_tree_unlock(mid
);
2185 free_extent_buffer(mid
);
2188 btrfs_header_nritems(left
);
2189 path
->slots
[level
] = orig_slot
;
2190 btrfs_tree_unlock(left
);
2191 free_extent_buffer(left
);
2195 btrfs_tree_unlock(left
);
2196 free_extent_buffer(left
);
2198 right
= read_node_slot(root
, parent
, pslot
+ 1);
2203 * then try to empty the right most buffer into the middle
2208 btrfs_tree_lock(right
);
2209 btrfs_set_lock_blocking(right
);
2211 right_nr
= btrfs_header_nritems(right
);
2212 if (right_nr
>= BTRFS_NODEPTRS_PER_BLOCK(root
) - 1) {
2215 ret
= btrfs_cow_block(trans
, root
, right
,
2221 wret
= balance_node_right(trans
, root
,
2228 struct btrfs_disk_key disk_key
;
2230 btrfs_node_key(right
, &disk_key
, 0);
2231 tree_mod_log_set_node_key(root
->fs_info
, parent
,
2233 btrfs_set_node_key(parent
, &disk_key
, pslot
+ 1);
2234 btrfs_mark_buffer_dirty(parent
);
2236 if (btrfs_header_nritems(mid
) <= orig_slot
) {
2237 path
->nodes
[level
] = right
;
2238 path
->slots
[level
+ 1] += 1;
2239 path
->slots
[level
] = orig_slot
-
2240 btrfs_header_nritems(mid
);
2241 btrfs_tree_unlock(mid
);
2242 free_extent_buffer(mid
);
2244 btrfs_tree_unlock(right
);
2245 free_extent_buffer(right
);
2249 btrfs_tree_unlock(right
);
2250 free_extent_buffer(right
);
2256 * readahead one full node of leaves, finding things that are close
2257 * to the block in 'slot', and triggering ra on them.
2259 static void reada_for_search(struct btrfs_root
*root
,
2260 struct btrfs_path
*path
,
2261 int level
, int slot
, u64 objectid
)
2263 struct extent_buffer
*node
;
2264 struct btrfs_disk_key disk_key
;
2269 struct extent_buffer
*eb
;
2277 if (!path
->nodes
[level
])
2280 node
= path
->nodes
[level
];
2282 search
= btrfs_node_blockptr(node
, slot
);
2283 blocksize
= root
->nodesize
;
2284 eb
= btrfs_find_tree_block(root
->fs_info
, search
);
2286 free_extent_buffer(eb
);
2292 nritems
= btrfs_header_nritems(node
);
2296 if (path
->reada
== READA_BACK
) {
2300 } else if (path
->reada
== READA_FORWARD
) {
2305 if (path
->reada
== READA_BACK
&& objectid
) {
2306 btrfs_node_key(node
, &disk_key
, nr
);
2307 if (btrfs_disk_key_objectid(&disk_key
) != objectid
)
2310 search
= btrfs_node_blockptr(node
, nr
);
2311 if ((search
<= target
&& target
- search
<= 65536) ||
2312 (search
> target
&& search
- target
<= 65536)) {
2313 readahead_tree_block(root
, search
);
2317 if ((nread
> 65536 || nscan
> 32))
2322 static noinline
void reada_for_balance(struct btrfs_root
*root
,
2323 struct btrfs_path
*path
, int level
)
2327 struct extent_buffer
*parent
;
2328 struct extent_buffer
*eb
;
2333 parent
= path
->nodes
[level
+ 1];
2337 nritems
= btrfs_header_nritems(parent
);
2338 slot
= path
->slots
[level
+ 1];
2341 block1
= btrfs_node_blockptr(parent
, slot
- 1);
2342 gen
= btrfs_node_ptr_generation(parent
, slot
- 1);
2343 eb
= btrfs_find_tree_block(root
->fs_info
, block1
);
2345 * if we get -eagain from btrfs_buffer_uptodate, we
2346 * don't want to return eagain here. That will loop
2349 if (eb
&& btrfs_buffer_uptodate(eb
, gen
, 1) != 0)
2351 free_extent_buffer(eb
);
2353 if (slot
+ 1 < nritems
) {
2354 block2
= btrfs_node_blockptr(parent
, slot
+ 1);
2355 gen
= btrfs_node_ptr_generation(parent
, slot
+ 1);
2356 eb
= btrfs_find_tree_block(root
->fs_info
, block2
);
2357 if (eb
&& btrfs_buffer_uptodate(eb
, gen
, 1) != 0)
2359 free_extent_buffer(eb
);
2363 readahead_tree_block(root
, block1
);
2365 readahead_tree_block(root
, block2
);
2370 * when we walk down the tree, it is usually safe to unlock the higher layers
2371 * in the tree. The exceptions are when our path goes through slot 0, because
2372 * operations on the tree might require changing key pointers higher up in the
2375 * callers might also have set path->keep_locks, which tells this code to keep
2376 * the lock if the path points to the last slot in the block. This is part of
2377 * walking through the tree, and selecting the next slot in the higher block.
2379 * lowest_unlock sets the lowest level in the tree we're allowed to unlock. so
2380 * if lowest_unlock is 1, level 0 won't be unlocked
2382 static noinline
void unlock_up(struct btrfs_path
*path
, int level
,
2383 int lowest_unlock
, int min_write_lock_level
,
2384 int *write_lock_level
)
2387 int skip_level
= level
;
2389 struct extent_buffer
*t
;
2391 for (i
= level
; i
< BTRFS_MAX_LEVEL
; i
++) {
2392 if (!path
->nodes
[i
])
2394 if (!path
->locks
[i
])
2396 if (!no_skips
&& path
->slots
[i
] == 0) {
2400 if (!no_skips
&& path
->keep_locks
) {
2403 nritems
= btrfs_header_nritems(t
);
2404 if (nritems
< 1 || path
->slots
[i
] >= nritems
- 1) {
2409 if (skip_level
< i
&& i
>= lowest_unlock
)
2413 if (i
>= lowest_unlock
&& i
> skip_level
&& path
->locks
[i
]) {
2414 btrfs_tree_unlock_rw(t
, path
->locks
[i
]);
2416 if (write_lock_level
&&
2417 i
> min_write_lock_level
&&
2418 i
<= *write_lock_level
) {
2419 *write_lock_level
= i
- 1;
2426 * This releases any locks held in the path starting at level and
2427 * going all the way up to the root.
2429 * btrfs_search_slot will keep the lock held on higher nodes in a few
2430 * corner cases, such as COW of the block at slot zero in the node. This
2431 * ignores those rules, and it should only be called when there are no
2432 * more updates to be done higher up in the tree.
2434 noinline
void btrfs_unlock_up_safe(struct btrfs_path
*path
, int level
)
2438 if (path
->keep_locks
)
2441 for (i
= level
; i
< BTRFS_MAX_LEVEL
; i
++) {
2442 if (!path
->nodes
[i
])
2444 if (!path
->locks
[i
])
2446 btrfs_tree_unlock_rw(path
->nodes
[i
], path
->locks
[i
]);
2452 * helper function for btrfs_search_slot. The goal is to find a block
2453 * in cache without setting the path to blocking. If we find the block
2454 * we return zero and the path is unchanged.
2456 * If we can't find the block, we set the path blocking and do some
2457 * reada. -EAGAIN is returned and the search must be repeated.
2460 read_block_for_search(struct btrfs_trans_handle
*trans
,
2461 struct btrfs_root
*root
, struct btrfs_path
*p
,
2462 struct extent_buffer
**eb_ret
, int level
, int slot
,
2463 struct btrfs_key
*key
, u64 time_seq
)
2467 struct extent_buffer
*b
= *eb_ret
;
2468 struct extent_buffer
*tmp
;
2471 blocknr
= btrfs_node_blockptr(b
, slot
);
2472 gen
= btrfs_node_ptr_generation(b
, slot
);
2474 tmp
= btrfs_find_tree_block(root
->fs_info
, blocknr
);
2476 /* first we do an atomic uptodate check */
2477 if (btrfs_buffer_uptodate(tmp
, gen
, 1) > 0) {
2482 /* the pages were up to date, but we failed
2483 * the generation number check. Do a full
2484 * read for the generation number that is correct.
2485 * We must do this without dropping locks so
2486 * we can trust our generation number
2488 btrfs_set_path_blocking(p
);
2490 /* now we're allowed to do a blocking uptodate check */
2491 ret
= btrfs_read_buffer(tmp
, gen
);
2496 free_extent_buffer(tmp
);
2497 btrfs_release_path(p
);
2502 * reduce lock contention at high levels
2503 * of the btree by dropping locks before
2504 * we read. Don't release the lock on the current
2505 * level because we need to walk this node to figure
2506 * out which blocks to read.
2508 btrfs_unlock_up_safe(p
, level
+ 1);
2509 btrfs_set_path_blocking(p
);
2511 free_extent_buffer(tmp
);
2512 if (p
->reada
!= READA_NONE
)
2513 reada_for_search(root
, p
, level
, slot
, key
->objectid
);
2515 btrfs_release_path(p
);
2518 tmp
= read_tree_block(root
, blocknr
, 0);
2521 * If the read above didn't mark this buffer up to date,
2522 * it will never end up being up to date. Set ret to EIO now
2523 * and give up so that our caller doesn't loop forever
2526 if (!btrfs_buffer_uptodate(tmp
, 0, 0))
2528 free_extent_buffer(tmp
);
2536 * helper function for btrfs_search_slot. This does all of the checks
2537 * for node-level blocks and does any balancing required based on
2540 * If no extra work was required, zero is returned. If we had to
2541 * drop the path, -EAGAIN is returned and btrfs_search_slot must
2545 setup_nodes_for_search(struct btrfs_trans_handle
*trans
,
2546 struct btrfs_root
*root
, struct btrfs_path
*p
,
2547 struct extent_buffer
*b
, int level
, int ins_len
,
2548 int *write_lock_level
)
2551 if ((p
->search_for_split
|| ins_len
> 0) && btrfs_header_nritems(b
) >=
2552 BTRFS_NODEPTRS_PER_BLOCK(root
) - 3) {
2555 if (*write_lock_level
< level
+ 1) {
2556 *write_lock_level
= level
+ 1;
2557 btrfs_release_path(p
);
2561 btrfs_set_path_blocking(p
);
2562 reada_for_balance(root
, p
, level
);
2563 sret
= split_node(trans
, root
, p
, level
);
2564 btrfs_clear_path_blocking(p
, NULL
, 0);
2571 b
= p
->nodes
[level
];
2572 } else if (ins_len
< 0 && btrfs_header_nritems(b
) <
2573 BTRFS_NODEPTRS_PER_BLOCK(root
) / 2) {
2576 if (*write_lock_level
< level
+ 1) {
2577 *write_lock_level
= level
+ 1;
2578 btrfs_release_path(p
);
2582 btrfs_set_path_blocking(p
);
2583 reada_for_balance(root
, p
, level
);
2584 sret
= balance_level(trans
, root
, p
, level
);
2585 btrfs_clear_path_blocking(p
, NULL
, 0);
2591 b
= p
->nodes
[level
];
2593 btrfs_release_path(p
);
2596 BUG_ON(btrfs_header_nritems(b
) == 1);
2606 static void key_search_validate(struct extent_buffer
*b
,
2607 struct btrfs_key
*key
,
2610 #ifdef CONFIG_BTRFS_ASSERT
2611 struct btrfs_disk_key disk_key
;
2613 btrfs_cpu_key_to_disk(&disk_key
, key
);
2616 ASSERT(!memcmp_extent_buffer(b
, &disk_key
,
2617 offsetof(struct btrfs_leaf
, items
[0].key
),
2620 ASSERT(!memcmp_extent_buffer(b
, &disk_key
,
2621 offsetof(struct btrfs_node
, ptrs
[0].key
),
2626 static int key_search(struct extent_buffer
*b
, struct btrfs_key
*key
,
2627 int level
, int *prev_cmp
, int *slot
)
2629 if (*prev_cmp
!= 0) {
2630 *prev_cmp
= bin_search(b
, key
, level
, slot
);
2634 key_search_validate(b
, key
, level
);
2640 int btrfs_find_item(struct btrfs_root
*fs_root
, struct btrfs_path
*path
,
2641 u64 iobjectid
, u64 ioff
, u8 key_type
,
2642 struct btrfs_key
*found_key
)
2645 struct btrfs_key key
;
2646 struct extent_buffer
*eb
;
2651 key
.type
= key_type
;
2652 key
.objectid
= iobjectid
;
2655 ret
= btrfs_search_slot(NULL
, fs_root
, &key
, path
, 0, 0);
2659 eb
= path
->nodes
[0];
2660 if (ret
&& path
->slots
[0] >= btrfs_header_nritems(eb
)) {
2661 ret
= btrfs_next_leaf(fs_root
, path
);
2664 eb
= path
->nodes
[0];
2667 btrfs_item_key_to_cpu(eb
, found_key
, path
->slots
[0]);
2668 if (found_key
->type
!= key
.type
||
2669 found_key
->objectid
!= key
.objectid
)
2676 * look for key in the tree. path is filled in with nodes along the way
2677 * if key is found, we return zero and you can find the item in the leaf
2678 * level of the path (level 0)
2680 * If the key isn't found, the path points to the slot where it should
2681 * be inserted, and 1 is returned. If there are other errors during the
2682 * search a negative error number is returned.
2684 * if ins_len > 0, nodes and leaves will be split as we walk down the
2685 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
2688 int btrfs_search_slot(struct btrfs_trans_handle
*trans
, struct btrfs_root
2689 *root
, struct btrfs_key
*key
, struct btrfs_path
*p
, int
2692 struct extent_buffer
*b
;
2697 int lowest_unlock
= 1;
2699 /* everything at write_lock_level or lower must be write locked */
2700 int write_lock_level
= 0;
2701 u8 lowest_level
= 0;
2702 int min_write_lock_level
;
2705 lowest_level
= p
->lowest_level
;
2706 WARN_ON(lowest_level
&& ins_len
> 0);
2707 WARN_ON(p
->nodes
[0] != NULL
);
2708 BUG_ON(!cow
&& ins_len
);
2713 /* when we are removing items, we might have to go up to level
2714 * two as we update tree pointers Make sure we keep write
2715 * for those levels as well
2717 write_lock_level
= 2;
2718 } else if (ins_len
> 0) {
2720 * for inserting items, make sure we have a write lock on
2721 * level 1 so we can update keys
2723 write_lock_level
= 1;
2727 write_lock_level
= -1;
2729 if (cow
&& (p
->keep_locks
|| p
->lowest_level
))
2730 write_lock_level
= BTRFS_MAX_LEVEL
;
2732 min_write_lock_level
= write_lock_level
;
2737 * we try very hard to do read locks on the root
2739 root_lock
= BTRFS_READ_LOCK
;
2741 if (p
->search_commit_root
) {
2743 * the commit roots are read only
2744 * so we always do read locks
2746 if (p
->need_commit_sem
)
2747 down_read(&root
->fs_info
->commit_root_sem
);
2748 b
= root
->commit_root
;
2749 extent_buffer_get(b
);
2750 level
= btrfs_header_level(b
);
2751 if (p
->need_commit_sem
)
2752 up_read(&root
->fs_info
->commit_root_sem
);
2753 if (!p
->skip_locking
)
2754 btrfs_tree_read_lock(b
);
2756 if (p
->skip_locking
) {
2757 b
= btrfs_root_node(root
);
2758 level
= btrfs_header_level(b
);
2760 /* we don't know the level of the root node
2761 * until we actually have it read locked
2763 b
= btrfs_read_lock_root_node(root
);
2764 level
= btrfs_header_level(b
);
2765 if (level
<= write_lock_level
) {
2766 /* whoops, must trade for write lock */
2767 btrfs_tree_read_unlock(b
);
2768 free_extent_buffer(b
);
2769 b
= btrfs_lock_root_node(root
);
2770 root_lock
= BTRFS_WRITE_LOCK
;
2772 /* the level might have changed, check again */
2773 level
= btrfs_header_level(b
);
2777 p
->nodes
[level
] = b
;
2778 if (!p
->skip_locking
)
2779 p
->locks
[level
] = root_lock
;
2782 level
= btrfs_header_level(b
);
2785 * setup the path here so we can release it under lock
2786 * contention with the cow code
2790 * if we don't really need to cow this block
2791 * then we don't want to set the path blocking,
2792 * so we test it here
2794 if (!should_cow_block(trans
, root
, b
)) {
2795 trans
->dirty
= true;
2800 * must have write locks on this node and the
2803 if (level
> write_lock_level
||
2804 (level
+ 1 > write_lock_level
&&
2805 level
+ 1 < BTRFS_MAX_LEVEL
&&
2806 p
->nodes
[level
+ 1])) {
2807 write_lock_level
= level
+ 1;
2808 btrfs_release_path(p
);
2812 btrfs_set_path_blocking(p
);
2813 err
= btrfs_cow_block(trans
, root
, b
,
2814 p
->nodes
[level
+ 1],
2815 p
->slots
[level
+ 1], &b
);
2822 p
->nodes
[level
] = b
;
2823 btrfs_clear_path_blocking(p
, NULL
, 0);
2826 * we have a lock on b and as long as we aren't changing
2827 * the tree, there is no way to for the items in b to change.
2828 * It is safe to drop the lock on our parent before we
2829 * go through the expensive btree search on b.
2831 * If we're inserting or deleting (ins_len != 0), then we might
2832 * be changing slot zero, which may require changing the parent.
2833 * So, we can't drop the lock until after we know which slot
2834 * we're operating on.
2836 if (!ins_len
&& !p
->keep_locks
) {
2839 if (u
< BTRFS_MAX_LEVEL
&& p
->locks
[u
]) {
2840 btrfs_tree_unlock_rw(p
->nodes
[u
], p
->locks
[u
]);
2845 ret
= key_search(b
, key
, level
, &prev_cmp
, &slot
);
2851 if (ret
&& slot
> 0) {
2855 p
->slots
[level
] = slot
;
2856 err
= setup_nodes_for_search(trans
, root
, p
, b
, level
,
2857 ins_len
, &write_lock_level
);
2864 b
= p
->nodes
[level
];
2865 slot
= p
->slots
[level
];
2868 * slot 0 is special, if we change the key
2869 * we have to update the parent pointer
2870 * which means we must have a write lock
2873 if (slot
== 0 && ins_len
&&
2874 write_lock_level
< level
+ 1) {
2875 write_lock_level
= level
+ 1;
2876 btrfs_release_path(p
);
2880 unlock_up(p
, level
, lowest_unlock
,
2881 min_write_lock_level
, &write_lock_level
);
2883 if (level
== lowest_level
) {
2889 err
= read_block_for_search(trans
, root
, p
,
2890 &b
, level
, slot
, key
, 0);
2898 if (!p
->skip_locking
) {
2899 level
= btrfs_header_level(b
);
2900 if (level
<= write_lock_level
) {
2901 err
= btrfs_try_tree_write_lock(b
);
2903 btrfs_set_path_blocking(p
);
2905 btrfs_clear_path_blocking(p
, b
,
2908 p
->locks
[level
] = BTRFS_WRITE_LOCK
;
2910 err
= btrfs_tree_read_lock_atomic(b
);
2912 btrfs_set_path_blocking(p
);
2913 btrfs_tree_read_lock(b
);
2914 btrfs_clear_path_blocking(p
, b
,
2917 p
->locks
[level
] = BTRFS_READ_LOCK
;
2919 p
->nodes
[level
] = b
;
2922 p
->slots
[level
] = slot
;
2924 btrfs_leaf_free_space(root
, b
) < ins_len
) {
2925 if (write_lock_level
< 1) {
2926 write_lock_level
= 1;
2927 btrfs_release_path(p
);
2931 btrfs_set_path_blocking(p
);
2932 err
= split_leaf(trans
, root
, key
,
2933 p
, ins_len
, ret
== 0);
2934 btrfs_clear_path_blocking(p
, NULL
, 0);
2942 if (!p
->search_for_split
)
2943 unlock_up(p
, level
, lowest_unlock
,
2944 min_write_lock_level
, &write_lock_level
);
2951 * we don't really know what they plan on doing with the path
2952 * from here on, so for now just mark it as blocking
2954 if (!p
->leave_spinning
)
2955 btrfs_set_path_blocking(p
);
2956 if (ret
< 0 && !p
->skip_release_on_error
)
2957 btrfs_release_path(p
);
2962 * Like btrfs_search_slot, this looks for a key in the given tree. It uses the
2963 * current state of the tree together with the operations recorded in the tree
2964 * modification log to search for the key in a previous version of this tree, as
2965 * denoted by the time_seq parameter.
2967 * Naturally, there is no support for insert, delete or cow operations.
2969 * The resulting path and return value will be set up as if we called
2970 * btrfs_search_slot at that point in time with ins_len and cow both set to 0.
2972 int btrfs_search_old_slot(struct btrfs_root
*root
, struct btrfs_key
*key
,
2973 struct btrfs_path
*p
, u64 time_seq
)
2975 struct extent_buffer
*b
;
2980 int lowest_unlock
= 1;
2981 u8 lowest_level
= 0;
2984 lowest_level
= p
->lowest_level
;
2985 WARN_ON(p
->nodes
[0] != NULL
);
2987 if (p
->search_commit_root
) {
2989 return btrfs_search_slot(NULL
, root
, key
, p
, 0, 0);
2993 b
= get_old_root(root
, time_seq
);
2994 level
= btrfs_header_level(b
);
2995 p
->locks
[level
] = BTRFS_READ_LOCK
;
2998 level
= btrfs_header_level(b
);
2999 p
->nodes
[level
] = b
;
3000 btrfs_clear_path_blocking(p
, NULL
, 0);
3003 * we have a lock on b and as long as we aren't changing
3004 * the tree, there is no way to for the items in b to change.
3005 * It is safe to drop the lock on our parent before we
3006 * go through the expensive btree search on b.
3008 btrfs_unlock_up_safe(p
, level
+ 1);
3011 * Since we can unwind ebs we want to do a real search every
3015 ret
= key_search(b
, key
, level
, &prev_cmp
, &slot
);
3019 if (ret
&& slot
> 0) {
3023 p
->slots
[level
] = slot
;
3024 unlock_up(p
, level
, lowest_unlock
, 0, NULL
);
3026 if (level
== lowest_level
) {
3032 err
= read_block_for_search(NULL
, root
, p
, &b
, level
,
3033 slot
, key
, time_seq
);
3041 level
= btrfs_header_level(b
);
3042 err
= btrfs_tree_read_lock_atomic(b
);
3044 btrfs_set_path_blocking(p
);
3045 btrfs_tree_read_lock(b
);
3046 btrfs_clear_path_blocking(p
, b
,
3049 b
= tree_mod_log_rewind(root
->fs_info
, p
, b
, time_seq
);
3054 p
->locks
[level
] = BTRFS_READ_LOCK
;
3055 p
->nodes
[level
] = b
;
3057 p
->slots
[level
] = slot
;
3058 unlock_up(p
, level
, lowest_unlock
, 0, NULL
);
3064 if (!p
->leave_spinning
)
3065 btrfs_set_path_blocking(p
);
3067 btrfs_release_path(p
);
3073 * helper to use instead of search slot if no exact match is needed but
3074 * instead the next or previous item should be returned.
3075 * When find_higher is true, the next higher item is returned, the next lower
3077 * When return_any and find_higher are both true, and no higher item is found,
3078 * return the next lower instead.
3079 * When return_any is true and find_higher is false, and no lower item is found,
3080 * return the next higher instead.
3081 * It returns 0 if any item is found, 1 if none is found (tree empty), and
3084 int btrfs_search_slot_for_read(struct btrfs_root
*root
,
3085 struct btrfs_key
*key
, struct btrfs_path
*p
,
3086 int find_higher
, int return_any
)
3089 struct extent_buffer
*leaf
;
3092 ret
= btrfs_search_slot(NULL
, root
, key
, p
, 0, 0);
3096 * a return value of 1 means the path is at the position where the
3097 * item should be inserted. Normally this is the next bigger item,
3098 * but in case the previous item is the last in a leaf, path points
3099 * to the first free slot in the previous leaf, i.e. at an invalid
3105 if (p
->slots
[0] >= btrfs_header_nritems(leaf
)) {
3106 ret
= btrfs_next_leaf(root
, p
);
3112 * no higher item found, return the next
3117 btrfs_release_path(p
);
3121 if (p
->slots
[0] == 0) {
3122 ret
= btrfs_prev_leaf(root
, p
);
3127 if (p
->slots
[0] == btrfs_header_nritems(leaf
))
3134 * no lower item found, return the next
3139 btrfs_release_path(p
);
3149 * adjust the pointers going up the tree, starting at level
3150 * making sure the right key of each node is points to 'key'.
3151 * This is used after shifting pointers to the left, so it stops
3152 * fixing up pointers when a given leaf/node is not in slot 0 of the
3156 static void fixup_low_keys(struct btrfs_fs_info
*fs_info
,
3157 struct btrfs_path
*path
,
3158 struct btrfs_disk_key
*key
, int level
)
3161 struct extent_buffer
*t
;
3163 for (i
= level
; i
< BTRFS_MAX_LEVEL
; i
++) {
3164 int tslot
= path
->slots
[i
];
3165 if (!path
->nodes
[i
])
3168 tree_mod_log_set_node_key(fs_info
, t
, tslot
, 1);
3169 btrfs_set_node_key(t
, key
, tslot
);
3170 btrfs_mark_buffer_dirty(path
->nodes
[i
]);
3179 * This function isn't completely safe. It's the caller's responsibility
3180 * that the new key won't break the order
3182 void btrfs_set_item_key_safe(struct btrfs_fs_info
*fs_info
,
3183 struct btrfs_path
*path
,
3184 struct btrfs_key
*new_key
)
3186 struct btrfs_disk_key disk_key
;
3187 struct extent_buffer
*eb
;
3190 eb
= path
->nodes
[0];
3191 slot
= path
->slots
[0];
3193 btrfs_item_key(eb
, &disk_key
, slot
- 1);
3194 BUG_ON(comp_keys(&disk_key
, new_key
) >= 0);
3196 if (slot
< btrfs_header_nritems(eb
) - 1) {
3197 btrfs_item_key(eb
, &disk_key
, slot
+ 1);
3198 BUG_ON(comp_keys(&disk_key
, new_key
) <= 0);
3201 btrfs_cpu_key_to_disk(&disk_key
, new_key
);
3202 btrfs_set_item_key(eb
, &disk_key
, slot
);
3203 btrfs_mark_buffer_dirty(eb
);
3205 fixup_low_keys(fs_info
, path
, &disk_key
, 1);
3209 * try to push data from one node into the next node left in the
3212 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
3213 * error, and > 0 if there was no room in the left hand block.
3215 static int push_node_left(struct btrfs_trans_handle
*trans
,
3216 struct btrfs_root
*root
, struct extent_buffer
*dst
,
3217 struct extent_buffer
*src
, int empty
)
3224 src_nritems
= btrfs_header_nritems(src
);
3225 dst_nritems
= btrfs_header_nritems(dst
);
3226 push_items
= BTRFS_NODEPTRS_PER_BLOCK(root
) - dst_nritems
;
3227 WARN_ON(btrfs_header_generation(src
) != trans
->transid
);
3228 WARN_ON(btrfs_header_generation(dst
) != trans
->transid
);
3230 if (!empty
&& src_nritems
<= 8)
3233 if (push_items
<= 0)
3237 push_items
= min(src_nritems
, push_items
);
3238 if (push_items
< src_nritems
) {
3239 /* leave at least 8 pointers in the node if
3240 * we aren't going to empty it
3242 if (src_nritems
- push_items
< 8) {
3243 if (push_items
<= 8)
3249 push_items
= min(src_nritems
- 8, push_items
);
3251 ret
= tree_mod_log_eb_copy(root
->fs_info
, dst
, src
, dst_nritems
, 0,
3254 btrfs_abort_transaction(trans
, ret
);
3257 copy_extent_buffer(dst
, src
,
3258 btrfs_node_key_ptr_offset(dst_nritems
),
3259 btrfs_node_key_ptr_offset(0),
3260 push_items
* sizeof(struct btrfs_key_ptr
));
3262 if (push_items
< src_nritems
) {
3264 * don't call tree_mod_log_eb_move here, key removal was already
3265 * fully logged by tree_mod_log_eb_copy above.
3267 memmove_extent_buffer(src
, btrfs_node_key_ptr_offset(0),
3268 btrfs_node_key_ptr_offset(push_items
),
3269 (src_nritems
- push_items
) *
3270 sizeof(struct btrfs_key_ptr
));
3272 btrfs_set_header_nritems(src
, src_nritems
- push_items
);
3273 btrfs_set_header_nritems(dst
, dst_nritems
+ push_items
);
3274 btrfs_mark_buffer_dirty(src
);
3275 btrfs_mark_buffer_dirty(dst
);
3281 * try to push data from one node into the next node right in the
3284 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
3285 * error, and > 0 if there was no room in the right hand block.
3287 * this will only push up to 1/2 the contents of the left node over
3289 static int balance_node_right(struct btrfs_trans_handle
*trans
,
3290 struct btrfs_root
*root
,
3291 struct extent_buffer
*dst
,
3292 struct extent_buffer
*src
)
3300 WARN_ON(btrfs_header_generation(src
) != trans
->transid
);
3301 WARN_ON(btrfs_header_generation(dst
) != trans
->transid
);
3303 src_nritems
= btrfs_header_nritems(src
);
3304 dst_nritems
= btrfs_header_nritems(dst
);
3305 push_items
= BTRFS_NODEPTRS_PER_BLOCK(root
) - dst_nritems
;
3306 if (push_items
<= 0)
3309 if (src_nritems
< 4)
3312 max_push
= src_nritems
/ 2 + 1;
3313 /* don't try to empty the node */
3314 if (max_push
>= src_nritems
)
3317 if (max_push
< push_items
)
3318 push_items
= max_push
;
3320 tree_mod_log_eb_move(root
->fs_info
, dst
, push_items
, 0, dst_nritems
);
3321 memmove_extent_buffer(dst
, btrfs_node_key_ptr_offset(push_items
),
3322 btrfs_node_key_ptr_offset(0),
3324 sizeof(struct btrfs_key_ptr
));
3326 ret
= tree_mod_log_eb_copy(root
->fs_info
, dst
, src
, 0,
3327 src_nritems
- push_items
, push_items
);
3329 btrfs_abort_transaction(trans
, ret
);
3332 copy_extent_buffer(dst
, src
,
3333 btrfs_node_key_ptr_offset(0),
3334 btrfs_node_key_ptr_offset(src_nritems
- push_items
),
3335 push_items
* sizeof(struct btrfs_key_ptr
));
3337 btrfs_set_header_nritems(src
, src_nritems
- push_items
);
3338 btrfs_set_header_nritems(dst
, dst_nritems
+ push_items
);
3340 btrfs_mark_buffer_dirty(src
);
3341 btrfs_mark_buffer_dirty(dst
);
3347 * helper function to insert a new root level in the tree.
3348 * A new node is allocated, and a single item is inserted to
3349 * point to the existing root
3351 * returns zero on success or < 0 on failure.
3353 static noinline
int insert_new_root(struct btrfs_trans_handle
*trans
,
3354 struct btrfs_root
*root
,
3355 struct btrfs_path
*path
, int level
)
3358 struct extent_buffer
*lower
;
3359 struct extent_buffer
*c
;
3360 struct extent_buffer
*old
;
3361 struct btrfs_disk_key lower_key
;
3363 BUG_ON(path
->nodes
[level
]);
3364 BUG_ON(path
->nodes
[level
-1] != root
->node
);
3366 lower
= path
->nodes
[level
-1];
3368 btrfs_item_key(lower
, &lower_key
, 0);
3370 btrfs_node_key(lower
, &lower_key
, 0);
3372 c
= btrfs_alloc_tree_block(trans
, root
, 0, root
->root_key
.objectid
,
3373 &lower_key
, level
, root
->node
->start
, 0);
3377 root_add_used(root
, root
->nodesize
);
3379 memset_extent_buffer(c
, 0, 0, sizeof(struct btrfs_header
));
3380 btrfs_set_header_nritems(c
, 1);
3381 btrfs_set_header_level(c
, level
);
3382 btrfs_set_header_bytenr(c
, c
->start
);
3383 btrfs_set_header_generation(c
, trans
->transid
);
3384 btrfs_set_header_backref_rev(c
, BTRFS_MIXED_BACKREF_REV
);
3385 btrfs_set_header_owner(c
, root
->root_key
.objectid
);
3387 write_extent_buffer(c
, root
->fs_info
->fsid
, btrfs_header_fsid(),
3390 write_extent_buffer(c
, root
->fs_info
->chunk_tree_uuid
,
3391 btrfs_header_chunk_tree_uuid(c
), BTRFS_UUID_SIZE
);
3393 btrfs_set_node_key(c
, &lower_key
, 0);
3394 btrfs_set_node_blockptr(c
, 0, lower
->start
);
3395 lower_gen
= btrfs_header_generation(lower
);
3396 WARN_ON(lower_gen
!= trans
->transid
);
3398 btrfs_set_node_ptr_generation(c
, 0, lower_gen
);
3400 btrfs_mark_buffer_dirty(c
);
3403 tree_mod_log_set_root_pointer(root
, c
, 0);
3404 rcu_assign_pointer(root
->node
, c
);
3406 /* the super has an extra ref to root->node */
3407 free_extent_buffer(old
);
3409 add_root_to_dirty_list(root
);
3410 extent_buffer_get(c
);
3411 path
->nodes
[level
] = c
;
3412 path
->locks
[level
] = BTRFS_WRITE_LOCK_BLOCKING
;
3413 path
->slots
[level
] = 0;
3418 * worker function to insert a single pointer in a node.
3419 * the node should have enough room for the pointer already
3421 * slot and level indicate where you want the key to go, and
3422 * blocknr is the block the key points to.
3424 static void insert_ptr(struct btrfs_trans_handle
*trans
,
3425 struct btrfs_root
*root
, struct btrfs_path
*path
,
3426 struct btrfs_disk_key
*key
, u64 bytenr
,
3427 int slot
, int level
)
3429 struct extent_buffer
*lower
;
3433 BUG_ON(!path
->nodes
[level
]);
3434 btrfs_assert_tree_locked(path
->nodes
[level
]);
3435 lower
= path
->nodes
[level
];
3436 nritems
= btrfs_header_nritems(lower
);
3437 BUG_ON(slot
> nritems
);
3438 BUG_ON(nritems
== BTRFS_NODEPTRS_PER_BLOCK(root
));
3439 if (slot
!= nritems
) {
3441 tree_mod_log_eb_move(root
->fs_info
, lower
, slot
+ 1,
3442 slot
, nritems
- slot
);
3443 memmove_extent_buffer(lower
,
3444 btrfs_node_key_ptr_offset(slot
+ 1),
3445 btrfs_node_key_ptr_offset(slot
),
3446 (nritems
- slot
) * sizeof(struct btrfs_key_ptr
));
3449 ret
= tree_mod_log_insert_key(root
->fs_info
, lower
, slot
,
3450 MOD_LOG_KEY_ADD
, GFP_NOFS
);
3453 btrfs_set_node_key(lower
, key
, slot
);
3454 btrfs_set_node_blockptr(lower
, slot
, bytenr
);
3455 WARN_ON(trans
->transid
== 0);
3456 btrfs_set_node_ptr_generation(lower
, slot
, trans
->transid
);
3457 btrfs_set_header_nritems(lower
, nritems
+ 1);
3458 btrfs_mark_buffer_dirty(lower
);
3462 * split the node at the specified level in path in two.
3463 * The path is corrected to point to the appropriate node after the split
3465 * Before splitting this tries to make some room in the node by pushing
3466 * left and right, if either one works, it returns right away.
3468 * returns 0 on success and < 0 on failure
3470 static noinline
int split_node(struct btrfs_trans_handle
*trans
,
3471 struct btrfs_root
*root
,
3472 struct btrfs_path
*path
, int level
)
3474 struct extent_buffer
*c
;
3475 struct extent_buffer
*split
;
3476 struct btrfs_disk_key disk_key
;
3481 c
= path
->nodes
[level
];
3482 WARN_ON(btrfs_header_generation(c
) != trans
->transid
);
3483 if (c
== root
->node
) {
3485 * trying to split the root, lets make a new one
3487 * tree mod log: We don't log_removal old root in
3488 * insert_new_root, because that root buffer will be kept as a
3489 * normal node. We are going to log removal of half of the
3490 * elements below with tree_mod_log_eb_copy. We're holding a
3491 * tree lock on the buffer, which is why we cannot race with
3492 * other tree_mod_log users.
3494 ret
= insert_new_root(trans
, root
, path
, level
+ 1);
3498 ret
= push_nodes_for_insert(trans
, root
, path
, level
);
3499 c
= path
->nodes
[level
];
3500 if (!ret
&& btrfs_header_nritems(c
) <
3501 BTRFS_NODEPTRS_PER_BLOCK(root
) - 3)
3507 c_nritems
= btrfs_header_nritems(c
);
3508 mid
= (c_nritems
+ 1) / 2;
3509 btrfs_node_key(c
, &disk_key
, mid
);
3511 split
= btrfs_alloc_tree_block(trans
, root
, 0, root
->root_key
.objectid
,
3512 &disk_key
, level
, c
->start
, 0);
3514 return PTR_ERR(split
);
3516 root_add_used(root
, root
->nodesize
);
3518 memset_extent_buffer(split
, 0, 0, sizeof(struct btrfs_header
));
3519 btrfs_set_header_level(split
, btrfs_header_level(c
));
3520 btrfs_set_header_bytenr(split
, split
->start
);
3521 btrfs_set_header_generation(split
, trans
->transid
);
3522 btrfs_set_header_backref_rev(split
, BTRFS_MIXED_BACKREF_REV
);
3523 btrfs_set_header_owner(split
, root
->root_key
.objectid
);
3524 write_extent_buffer(split
, root
->fs_info
->fsid
,
3525 btrfs_header_fsid(), BTRFS_FSID_SIZE
);
3526 write_extent_buffer(split
, root
->fs_info
->chunk_tree_uuid
,
3527 btrfs_header_chunk_tree_uuid(split
),
3530 ret
= tree_mod_log_eb_copy(root
->fs_info
, split
, c
, 0,
3531 mid
, c_nritems
- mid
);
3533 btrfs_abort_transaction(trans
, ret
);
3536 copy_extent_buffer(split
, c
,
3537 btrfs_node_key_ptr_offset(0),
3538 btrfs_node_key_ptr_offset(mid
),
3539 (c_nritems
- mid
) * sizeof(struct btrfs_key_ptr
));
3540 btrfs_set_header_nritems(split
, c_nritems
- mid
);
3541 btrfs_set_header_nritems(c
, mid
);
3544 btrfs_mark_buffer_dirty(c
);
3545 btrfs_mark_buffer_dirty(split
);
3547 insert_ptr(trans
, root
, path
, &disk_key
, split
->start
,
3548 path
->slots
[level
+ 1] + 1, level
+ 1);
3550 if (path
->slots
[level
] >= mid
) {
3551 path
->slots
[level
] -= mid
;
3552 btrfs_tree_unlock(c
);
3553 free_extent_buffer(c
);
3554 path
->nodes
[level
] = split
;
3555 path
->slots
[level
+ 1] += 1;
3557 btrfs_tree_unlock(split
);
3558 free_extent_buffer(split
);
3564 * how many bytes are required to store the items in a leaf. start
3565 * and nr indicate which items in the leaf to check. This totals up the
3566 * space used both by the item structs and the item data
3568 static int leaf_space_used(struct extent_buffer
*l
, int start
, int nr
)
3570 struct btrfs_item
*start_item
;
3571 struct btrfs_item
*end_item
;
3572 struct btrfs_map_token token
;
3574 int nritems
= btrfs_header_nritems(l
);
3575 int end
= min(nritems
, start
+ nr
) - 1;
3579 btrfs_init_map_token(&token
);
3580 start_item
= btrfs_item_nr(start
);
3581 end_item
= btrfs_item_nr(end
);
3582 data_len
= btrfs_token_item_offset(l
, start_item
, &token
) +
3583 btrfs_token_item_size(l
, start_item
, &token
);
3584 data_len
= data_len
- btrfs_token_item_offset(l
, end_item
, &token
);
3585 data_len
+= sizeof(struct btrfs_item
) * nr
;
3586 WARN_ON(data_len
< 0);
3591 * The space between the end of the leaf items and
3592 * the start of the leaf data. IOW, how much room
3593 * the leaf has left for both items and data
3595 noinline
int btrfs_leaf_free_space(struct btrfs_root
*root
,
3596 struct extent_buffer
*leaf
)
3598 int nritems
= btrfs_header_nritems(leaf
);
3600 ret
= BTRFS_LEAF_DATA_SIZE(root
) - leaf_space_used(leaf
, 0, nritems
);
3602 btrfs_crit(root
->fs_info
,
3603 "leaf free space ret %d, leaf data size %lu, used %d nritems %d",
3604 ret
, (unsigned long) BTRFS_LEAF_DATA_SIZE(root
),
3605 leaf_space_used(leaf
, 0, nritems
), nritems
);
3611 * min slot controls the lowest index we're willing to push to the
3612 * right. We'll push up to and including min_slot, but no lower
3614 static noinline
int __push_leaf_right(struct btrfs_trans_handle
*trans
,
3615 struct btrfs_root
*root
,
3616 struct btrfs_path
*path
,
3617 int data_size
, int empty
,
3618 struct extent_buffer
*right
,
3619 int free_space
, u32 left_nritems
,
3622 struct extent_buffer
*left
= path
->nodes
[0];
3623 struct extent_buffer
*upper
= path
->nodes
[1];
3624 struct btrfs_map_token token
;
3625 struct btrfs_disk_key disk_key
;
3630 struct btrfs_item
*item
;
3636 btrfs_init_map_token(&token
);
3641 nr
= max_t(u32
, 1, min_slot
);
3643 if (path
->slots
[0] >= left_nritems
)
3644 push_space
+= data_size
;
3646 slot
= path
->slots
[1];
3647 i
= left_nritems
- 1;
3649 item
= btrfs_item_nr(i
);
3651 if (!empty
&& push_items
> 0) {
3652 if (path
->slots
[0] > i
)
3654 if (path
->slots
[0] == i
) {
3655 int space
= btrfs_leaf_free_space(root
, left
);
3656 if (space
+ push_space
* 2 > free_space
)
3661 if (path
->slots
[0] == i
)
3662 push_space
+= data_size
;
3664 this_item_size
= btrfs_item_size(left
, item
);
3665 if (this_item_size
+ sizeof(*item
) + push_space
> free_space
)
3669 push_space
+= this_item_size
+ sizeof(*item
);
3675 if (push_items
== 0)
3678 WARN_ON(!empty
&& push_items
== left_nritems
);
3680 /* push left to right */
3681 right_nritems
= btrfs_header_nritems(right
);
3683 push_space
= btrfs_item_end_nr(left
, left_nritems
- push_items
);
3684 push_space
-= leaf_data_end(root
, left
);
3686 /* make room in the right data area */
3687 data_end
= leaf_data_end(root
, right
);
3688 memmove_extent_buffer(right
,
3689 btrfs_leaf_data(right
) + data_end
- push_space
,
3690 btrfs_leaf_data(right
) + data_end
,
3691 BTRFS_LEAF_DATA_SIZE(root
) - data_end
);
3693 /* copy from the left data area */
3694 copy_extent_buffer(right
, left
, btrfs_leaf_data(right
) +
3695 BTRFS_LEAF_DATA_SIZE(root
) - push_space
,
3696 btrfs_leaf_data(left
) + leaf_data_end(root
, left
),
3699 memmove_extent_buffer(right
, btrfs_item_nr_offset(push_items
),
3700 btrfs_item_nr_offset(0),
3701 right_nritems
* sizeof(struct btrfs_item
));
3703 /* copy the items from left to right */
3704 copy_extent_buffer(right
, left
, btrfs_item_nr_offset(0),
3705 btrfs_item_nr_offset(left_nritems
- push_items
),
3706 push_items
* sizeof(struct btrfs_item
));
3708 /* update the item pointers */
3709 right_nritems
+= push_items
;
3710 btrfs_set_header_nritems(right
, right_nritems
);
3711 push_space
= BTRFS_LEAF_DATA_SIZE(root
);
3712 for (i
= 0; i
< right_nritems
; i
++) {
3713 item
= btrfs_item_nr(i
);
3714 push_space
-= btrfs_token_item_size(right
, item
, &token
);
3715 btrfs_set_token_item_offset(right
, item
, push_space
, &token
);
3718 left_nritems
-= push_items
;
3719 btrfs_set_header_nritems(left
, left_nritems
);
3722 btrfs_mark_buffer_dirty(left
);
3724 clean_tree_block(trans
, root
->fs_info
, left
);
3726 btrfs_mark_buffer_dirty(right
);
3728 btrfs_item_key(right
, &disk_key
, 0);
3729 btrfs_set_node_key(upper
, &disk_key
, slot
+ 1);
3730 btrfs_mark_buffer_dirty(upper
);
3732 /* then fixup the leaf pointer in the path */
3733 if (path
->slots
[0] >= left_nritems
) {
3734 path
->slots
[0] -= left_nritems
;
3735 if (btrfs_header_nritems(path
->nodes
[0]) == 0)
3736 clean_tree_block(trans
, root
->fs_info
, path
->nodes
[0]);
3737 btrfs_tree_unlock(path
->nodes
[0]);
3738 free_extent_buffer(path
->nodes
[0]);
3739 path
->nodes
[0] = right
;
3740 path
->slots
[1] += 1;
3742 btrfs_tree_unlock(right
);
3743 free_extent_buffer(right
);
3748 btrfs_tree_unlock(right
);
3749 free_extent_buffer(right
);
3754 * push some data in the path leaf to the right, trying to free up at
3755 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3757 * returns 1 if the push failed because the other node didn't have enough
3758 * room, 0 if everything worked out and < 0 if there were major errors.
3760 * this will push starting from min_slot to the end of the leaf. It won't
3761 * push any slot lower than min_slot
3763 static int push_leaf_right(struct btrfs_trans_handle
*trans
, struct btrfs_root
3764 *root
, struct btrfs_path
*path
,
3765 int min_data_size
, int data_size
,
3766 int empty
, u32 min_slot
)
3768 struct extent_buffer
*left
= path
->nodes
[0];
3769 struct extent_buffer
*right
;
3770 struct extent_buffer
*upper
;
3776 if (!path
->nodes
[1])
3779 slot
= path
->slots
[1];
3780 upper
= path
->nodes
[1];
3781 if (slot
>= btrfs_header_nritems(upper
) - 1)
3784 btrfs_assert_tree_locked(path
->nodes
[1]);
3786 right
= read_node_slot(root
, upper
, slot
+ 1);
3788 * slot + 1 is not valid or we fail to read the right node,
3789 * no big deal, just return.
3794 btrfs_tree_lock(right
);
3795 btrfs_set_lock_blocking(right
);
3797 free_space
= btrfs_leaf_free_space(root
, right
);
3798 if (free_space
< data_size
)
3801 /* cow and double check */
3802 ret
= btrfs_cow_block(trans
, root
, right
, upper
,
3807 free_space
= btrfs_leaf_free_space(root
, right
);
3808 if (free_space
< data_size
)
3811 left_nritems
= btrfs_header_nritems(left
);
3812 if (left_nritems
== 0)
3815 if (path
->slots
[0] == left_nritems
&& !empty
) {
3816 /* Key greater than all keys in the leaf, right neighbor has
3817 * enough room for it and we're not emptying our leaf to delete
3818 * it, therefore use right neighbor to insert the new item and
3819 * no need to touch/dirty our left leaft. */
3820 btrfs_tree_unlock(left
);
3821 free_extent_buffer(left
);
3822 path
->nodes
[0] = right
;
3828 return __push_leaf_right(trans
, root
, path
, min_data_size
, empty
,
3829 right
, free_space
, left_nritems
, min_slot
);
3831 btrfs_tree_unlock(right
);
3832 free_extent_buffer(right
);
3837 * push some data in the path leaf to the left, trying to free up at
3838 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3840 * max_slot can put a limit on how far into the leaf we'll push items. The
3841 * item at 'max_slot' won't be touched. Use (u32)-1 to make us do all the
3844 static noinline
int __push_leaf_left(struct btrfs_trans_handle
*trans
,
3845 struct btrfs_root
*root
,
3846 struct btrfs_path
*path
, int data_size
,
3847 int empty
, struct extent_buffer
*left
,
3848 int free_space
, u32 right_nritems
,
3851 struct btrfs_disk_key disk_key
;
3852 struct extent_buffer
*right
= path
->nodes
[0];
3856 struct btrfs_item
*item
;
3857 u32 old_left_nritems
;
3861 u32 old_left_item_size
;
3862 struct btrfs_map_token token
;
3864 btrfs_init_map_token(&token
);
3867 nr
= min(right_nritems
, max_slot
);
3869 nr
= min(right_nritems
- 1, max_slot
);
3871 for (i
= 0; i
< nr
; i
++) {
3872 item
= btrfs_item_nr(i
);
3874 if (!empty
&& push_items
> 0) {
3875 if (path
->slots
[0] < i
)
3877 if (path
->slots
[0] == i
) {
3878 int space
= btrfs_leaf_free_space(root
, right
);
3879 if (space
+ push_space
* 2 > free_space
)
3884 if (path
->slots
[0] == i
)
3885 push_space
+= data_size
;
3887 this_item_size
= btrfs_item_size(right
, item
);
3888 if (this_item_size
+ sizeof(*item
) + push_space
> free_space
)
3892 push_space
+= this_item_size
+ sizeof(*item
);
3895 if (push_items
== 0) {
3899 WARN_ON(!empty
&& push_items
== btrfs_header_nritems(right
));
3901 /* push data from right to left */
3902 copy_extent_buffer(left
, right
,
3903 btrfs_item_nr_offset(btrfs_header_nritems(left
)),
3904 btrfs_item_nr_offset(0),
3905 push_items
* sizeof(struct btrfs_item
));
3907 push_space
= BTRFS_LEAF_DATA_SIZE(root
) -
3908 btrfs_item_offset_nr(right
, push_items
- 1);
3910 copy_extent_buffer(left
, right
, btrfs_leaf_data(left
) +
3911 leaf_data_end(root
, left
) - push_space
,
3912 btrfs_leaf_data(right
) +
3913 btrfs_item_offset_nr(right
, push_items
- 1),
3915 old_left_nritems
= btrfs_header_nritems(left
);
3916 BUG_ON(old_left_nritems
<= 0);
3918 old_left_item_size
= btrfs_item_offset_nr(left
, old_left_nritems
- 1);
3919 for (i
= old_left_nritems
; i
< old_left_nritems
+ push_items
; i
++) {
3922 item
= btrfs_item_nr(i
);
3924 ioff
= btrfs_token_item_offset(left
, item
, &token
);
3925 btrfs_set_token_item_offset(left
, item
,
3926 ioff
- (BTRFS_LEAF_DATA_SIZE(root
) - old_left_item_size
),
3929 btrfs_set_header_nritems(left
, old_left_nritems
+ push_items
);
3931 /* fixup right node */
3932 if (push_items
> right_nritems
)
3933 WARN(1, KERN_CRIT
"push items %d nr %u\n", push_items
,
3936 if (push_items
< right_nritems
) {
3937 push_space
= btrfs_item_offset_nr(right
, push_items
- 1) -
3938 leaf_data_end(root
, right
);
3939 memmove_extent_buffer(right
, btrfs_leaf_data(right
) +
3940 BTRFS_LEAF_DATA_SIZE(root
) - push_space
,
3941 btrfs_leaf_data(right
) +
3942 leaf_data_end(root
, right
), push_space
);
3944 memmove_extent_buffer(right
, btrfs_item_nr_offset(0),
3945 btrfs_item_nr_offset(push_items
),
3946 (btrfs_header_nritems(right
) - push_items
) *
3947 sizeof(struct btrfs_item
));
3949 right_nritems
-= push_items
;
3950 btrfs_set_header_nritems(right
, right_nritems
);
3951 push_space
= BTRFS_LEAF_DATA_SIZE(root
);
3952 for (i
= 0; i
< right_nritems
; i
++) {
3953 item
= btrfs_item_nr(i
);
3955 push_space
= push_space
- btrfs_token_item_size(right
,
3957 btrfs_set_token_item_offset(right
, item
, push_space
, &token
);
3960 btrfs_mark_buffer_dirty(left
);
3962 btrfs_mark_buffer_dirty(right
);
3964 clean_tree_block(trans
, root
->fs_info
, right
);
3966 btrfs_item_key(right
, &disk_key
, 0);
3967 fixup_low_keys(root
->fs_info
, path
, &disk_key
, 1);
3969 /* then fixup the leaf pointer in the path */
3970 if (path
->slots
[0] < push_items
) {
3971 path
->slots
[0] += old_left_nritems
;
3972 btrfs_tree_unlock(path
->nodes
[0]);
3973 free_extent_buffer(path
->nodes
[0]);
3974 path
->nodes
[0] = left
;
3975 path
->slots
[1] -= 1;
3977 btrfs_tree_unlock(left
);
3978 free_extent_buffer(left
);
3979 path
->slots
[0] -= push_items
;
3981 BUG_ON(path
->slots
[0] < 0);
3984 btrfs_tree_unlock(left
);
3985 free_extent_buffer(left
);
3990 * push some data in the path leaf to the left, trying to free up at
3991 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3993 * max_slot can put a limit on how far into the leaf we'll push items. The
3994 * item at 'max_slot' won't be touched. Use (u32)-1 to make us push all the
3997 static int push_leaf_left(struct btrfs_trans_handle
*trans
, struct btrfs_root
3998 *root
, struct btrfs_path
*path
, int min_data_size
,
3999 int data_size
, int empty
, u32 max_slot
)
4001 struct extent_buffer
*right
= path
->nodes
[0];
4002 struct extent_buffer
*left
;
4008 slot
= path
->slots
[1];
4011 if (!path
->nodes
[1])
4014 right_nritems
= btrfs_header_nritems(right
);
4015 if (right_nritems
== 0)
4018 btrfs_assert_tree_locked(path
->nodes
[1]);
4020 left
= read_node_slot(root
, path
->nodes
[1], slot
- 1);
4022 * slot - 1 is not valid or we fail to read the left node,
4023 * no big deal, just return.
4028 btrfs_tree_lock(left
);
4029 btrfs_set_lock_blocking(left
);
4031 free_space
= btrfs_leaf_free_space(root
, left
);
4032 if (free_space
< data_size
) {
4037 /* cow and double check */
4038 ret
= btrfs_cow_block(trans
, root
, left
,
4039 path
->nodes
[1], slot
- 1, &left
);
4041 /* we hit -ENOSPC, but it isn't fatal here */
4047 free_space
= btrfs_leaf_free_space(root
, left
);
4048 if (free_space
< data_size
) {
4053 return __push_leaf_left(trans
, root
, path
, min_data_size
,
4054 empty
, left
, free_space
, right_nritems
,
4057 btrfs_tree_unlock(left
);
4058 free_extent_buffer(left
);
4063 * split the path's leaf in two, making sure there is at least data_size
4064 * available for the resulting leaf level of the path.
4066 static noinline
void copy_for_split(struct btrfs_trans_handle
*trans
,
4067 struct btrfs_root
*root
,
4068 struct btrfs_path
*path
,
4069 struct extent_buffer
*l
,
4070 struct extent_buffer
*right
,
4071 int slot
, int mid
, int nritems
)
4076 struct btrfs_disk_key disk_key
;
4077 struct btrfs_map_token token
;
4079 btrfs_init_map_token(&token
);
4081 nritems
= nritems
- mid
;
4082 btrfs_set_header_nritems(right
, nritems
);
4083 data_copy_size
= btrfs_item_end_nr(l
, mid
) - leaf_data_end(root
, l
);
4085 copy_extent_buffer(right
, l
, btrfs_item_nr_offset(0),
4086 btrfs_item_nr_offset(mid
),
4087 nritems
* sizeof(struct btrfs_item
));
4089 copy_extent_buffer(right
, l
,
4090 btrfs_leaf_data(right
) + BTRFS_LEAF_DATA_SIZE(root
) -
4091 data_copy_size
, btrfs_leaf_data(l
) +
4092 leaf_data_end(root
, l
), data_copy_size
);
4094 rt_data_off
= BTRFS_LEAF_DATA_SIZE(root
) -
4095 btrfs_item_end_nr(l
, mid
);
4097 for (i
= 0; i
< nritems
; i
++) {
4098 struct btrfs_item
*item
= btrfs_item_nr(i
);
4101 ioff
= btrfs_token_item_offset(right
, item
, &token
);
4102 btrfs_set_token_item_offset(right
, item
,
4103 ioff
+ rt_data_off
, &token
);
4106 btrfs_set_header_nritems(l
, mid
);
4107 btrfs_item_key(right
, &disk_key
, 0);
4108 insert_ptr(trans
, root
, path
, &disk_key
, right
->start
,
4109 path
->slots
[1] + 1, 1);
4111 btrfs_mark_buffer_dirty(right
);
4112 btrfs_mark_buffer_dirty(l
);
4113 BUG_ON(path
->slots
[0] != slot
);
4116 btrfs_tree_unlock(path
->nodes
[0]);
4117 free_extent_buffer(path
->nodes
[0]);
4118 path
->nodes
[0] = right
;
4119 path
->slots
[0] -= mid
;
4120 path
->slots
[1] += 1;
4122 btrfs_tree_unlock(right
);
4123 free_extent_buffer(right
);
4126 BUG_ON(path
->slots
[0] < 0);
4130 * double splits happen when we need to insert a big item in the middle
4131 * of a leaf. A double split can leave us with 3 mostly empty leaves:
4132 * leaf: [ slots 0 - N] [ our target ] [ N + 1 - total in leaf ]
4135 * We avoid this by trying to push the items on either side of our target
4136 * into the adjacent leaves. If all goes well we can avoid the double split
4139 static noinline
int push_for_double_split(struct btrfs_trans_handle
*trans
,
4140 struct btrfs_root
*root
,
4141 struct btrfs_path
*path
,
4148 int space_needed
= data_size
;
4150 slot
= path
->slots
[0];
4151 if (slot
< btrfs_header_nritems(path
->nodes
[0]))
4152 space_needed
-= btrfs_leaf_free_space(root
, path
->nodes
[0]);
4155 * try to push all the items after our slot into the
4158 ret
= push_leaf_right(trans
, root
, path
, 1, space_needed
, 0, slot
);
4165 nritems
= btrfs_header_nritems(path
->nodes
[0]);
4167 * our goal is to get our slot at the start or end of a leaf. If
4168 * we've done so we're done
4170 if (path
->slots
[0] == 0 || path
->slots
[0] == nritems
)
4173 if (btrfs_leaf_free_space(root
, path
->nodes
[0]) >= data_size
)
4176 /* try to push all the items before our slot into the next leaf */
4177 slot
= path
->slots
[0];
4178 ret
= push_leaf_left(trans
, root
, path
, 1, space_needed
, 0, slot
);
4191 * split the path's leaf in two, making sure there is at least data_size
4192 * available for the resulting leaf level of the path.
4194 * returns 0 if all went well and < 0 on failure.
4196 static noinline
int split_leaf(struct btrfs_trans_handle
*trans
,
4197 struct btrfs_root
*root
,
4198 struct btrfs_key
*ins_key
,
4199 struct btrfs_path
*path
, int data_size
,
4202 struct btrfs_disk_key disk_key
;
4203 struct extent_buffer
*l
;
4207 struct extent_buffer
*right
;
4208 struct btrfs_fs_info
*fs_info
= root
->fs_info
;
4212 int num_doubles
= 0;
4213 int tried_avoid_double
= 0;
4216 slot
= path
->slots
[0];
4217 if (extend
&& data_size
+ btrfs_item_size_nr(l
, slot
) +
4218 sizeof(struct btrfs_item
) > BTRFS_LEAF_DATA_SIZE(root
))
4221 /* first try to make some room by pushing left and right */
4222 if (data_size
&& path
->nodes
[1]) {
4223 int space_needed
= data_size
;
4225 if (slot
< btrfs_header_nritems(l
))
4226 space_needed
-= btrfs_leaf_free_space(root
, l
);
4228 wret
= push_leaf_right(trans
, root
, path
, space_needed
,
4229 space_needed
, 0, 0);
4233 wret
= push_leaf_left(trans
, root
, path
, space_needed
,
4234 space_needed
, 0, (u32
)-1);
4240 /* did the pushes work? */
4241 if (btrfs_leaf_free_space(root
, l
) >= data_size
)
4245 if (!path
->nodes
[1]) {
4246 ret
= insert_new_root(trans
, root
, path
, 1);
4253 slot
= path
->slots
[0];
4254 nritems
= btrfs_header_nritems(l
);
4255 mid
= (nritems
+ 1) / 2;
4259 leaf_space_used(l
, mid
, nritems
- mid
) + data_size
>
4260 BTRFS_LEAF_DATA_SIZE(root
)) {
4261 if (slot
>= nritems
) {
4265 if (mid
!= nritems
&&
4266 leaf_space_used(l
, mid
, nritems
- mid
) +
4267 data_size
> BTRFS_LEAF_DATA_SIZE(root
)) {
4268 if (data_size
&& !tried_avoid_double
)
4269 goto push_for_double
;
4275 if (leaf_space_used(l
, 0, mid
) + data_size
>
4276 BTRFS_LEAF_DATA_SIZE(root
)) {
4277 if (!extend
&& data_size
&& slot
== 0) {
4279 } else if ((extend
|| !data_size
) && slot
== 0) {
4283 if (mid
!= nritems
&&
4284 leaf_space_used(l
, mid
, nritems
- mid
) +
4285 data_size
> BTRFS_LEAF_DATA_SIZE(root
)) {
4286 if (data_size
&& !tried_avoid_double
)
4287 goto push_for_double
;
4295 btrfs_cpu_key_to_disk(&disk_key
, ins_key
);
4297 btrfs_item_key(l
, &disk_key
, mid
);
4299 right
= btrfs_alloc_tree_block(trans
, root
, 0, root
->root_key
.objectid
,
4300 &disk_key
, 0, l
->start
, 0);
4302 return PTR_ERR(right
);
4304 root_add_used(root
, root
->nodesize
);
4306 memset_extent_buffer(right
, 0, 0, sizeof(struct btrfs_header
));
4307 btrfs_set_header_bytenr(right
, right
->start
);
4308 btrfs_set_header_generation(right
, trans
->transid
);
4309 btrfs_set_header_backref_rev(right
, BTRFS_MIXED_BACKREF_REV
);
4310 btrfs_set_header_owner(right
, root
->root_key
.objectid
);
4311 btrfs_set_header_level(right
, 0);
4312 write_extent_buffer(right
, fs_info
->fsid
,
4313 btrfs_header_fsid(), BTRFS_FSID_SIZE
);
4315 write_extent_buffer(right
, fs_info
->chunk_tree_uuid
,
4316 btrfs_header_chunk_tree_uuid(right
),
4321 btrfs_set_header_nritems(right
, 0);
4322 insert_ptr(trans
, root
, path
, &disk_key
, right
->start
,
4323 path
->slots
[1] + 1, 1);
4324 btrfs_tree_unlock(path
->nodes
[0]);
4325 free_extent_buffer(path
->nodes
[0]);
4326 path
->nodes
[0] = right
;
4328 path
->slots
[1] += 1;
4330 btrfs_set_header_nritems(right
, 0);
4331 insert_ptr(trans
, root
, path
, &disk_key
, right
->start
,
4333 btrfs_tree_unlock(path
->nodes
[0]);
4334 free_extent_buffer(path
->nodes
[0]);
4335 path
->nodes
[0] = right
;
4337 if (path
->slots
[1] == 0)
4338 fixup_low_keys(fs_info
, path
, &disk_key
, 1);
4340 btrfs_mark_buffer_dirty(right
);
4344 copy_for_split(trans
, root
, path
, l
, right
, slot
, mid
, nritems
);
4347 BUG_ON(num_doubles
!= 0);
4355 push_for_double_split(trans
, root
, path
, data_size
);
4356 tried_avoid_double
= 1;
4357 if (btrfs_leaf_free_space(root
, path
->nodes
[0]) >= data_size
)
4362 static noinline
int setup_leaf_for_split(struct btrfs_trans_handle
*trans
,
4363 struct btrfs_root
*root
,
4364 struct btrfs_path
*path
, int ins_len
)
4366 struct btrfs_key key
;
4367 struct extent_buffer
*leaf
;
4368 struct btrfs_file_extent_item
*fi
;
4373 leaf
= path
->nodes
[0];
4374 btrfs_item_key_to_cpu(leaf
, &key
, path
->slots
[0]);
4376 BUG_ON(key
.type
!= BTRFS_EXTENT_DATA_KEY
&&
4377 key
.type
!= BTRFS_EXTENT_CSUM_KEY
);
4379 if (btrfs_leaf_free_space(root
, leaf
) >= ins_len
)
4382 item_size
= btrfs_item_size_nr(leaf
, path
->slots
[0]);
4383 if (key
.type
== BTRFS_EXTENT_DATA_KEY
) {
4384 fi
= btrfs_item_ptr(leaf
, path
->slots
[0],
4385 struct btrfs_file_extent_item
);
4386 extent_len
= btrfs_file_extent_num_bytes(leaf
, fi
);
4388 btrfs_release_path(path
);
4390 path
->keep_locks
= 1;
4391 path
->search_for_split
= 1;
4392 ret
= btrfs_search_slot(trans
, root
, &key
, path
, 0, 1);
4393 path
->search_for_split
= 0;
4400 leaf
= path
->nodes
[0];
4401 /* if our item isn't there, return now */
4402 if (item_size
!= btrfs_item_size_nr(leaf
, path
->slots
[0]))
4405 /* the leaf has changed, it now has room. return now */
4406 if (btrfs_leaf_free_space(root
, path
->nodes
[0]) >= ins_len
)
4409 if (key
.type
== BTRFS_EXTENT_DATA_KEY
) {
4410 fi
= btrfs_item_ptr(leaf
, path
->slots
[0],
4411 struct btrfs_file_extent_item
);
4412 if (extent_len
!= btrfs_file_extent_num_bytes(leaf
, fi
))
4416 btrfs_set_path_blocking(path
);
4417 ret
= split_leaf(trans
, root
, &key
, path
, ins_len
, 1);
4421 path
->keep_locks
= 0;
4422 btrfs_unlock_up_safe(path
, 1);
4425 path
->keep_locks
= 0;
4429 static noinline
int split_item(struct btrfs_trans_handle
*trans
,
4430 struct btrfs_root
*root
,
4431 struct btrfs_path
*path
,
4432 struct btrfs_key
*new_key
,
4433 unsigned long split_offset
)
4435 struct extent_buffer
*leaf
;
4436 struct btrfs_item
*item
;
4437 struct btrfs_item
*new_item
;
4443 struct btrfs_disk_key disk_key
;
4445 leaf
= path
->nodes
[0];
4446 BUG_ON(btrfs_leaf_free_space(root
, leaf
) < sizeof(struct btrfs_item
));
4448 btrfs_set_path_blocking(path
);
4450 item
= btrfs_item_nr(path
->slots
[0]);
4451 orig_offset
= btrfs_item_offset(leaf
, item
);
4452 item_size
= btrfs_item_size(leaf
, item
);
4454 buf
= kmalloc(item_size
, GFP_NOFS
);
4458 read_extent_buffer(leaf
, buf
, btrfs_item_ptr_offset(leaf
,
4459 path
->slots
[0]), item_size
);
4461 slot
= path
->slots
[0] + 1;
4462 nritems
= btrfs_header_nritems(leaf
);
4463 if (slot
!= nritems
) {
4464 /* shift the items */
4465 memmove_extent_buffer(leaf
, btrfs_item_nr_offset(slot
+ 1),
4466 btrfs_item_nr_offset(slot
),
4467 (nritems
- slot
) * sizeof(struct btrfs_item
));
4470 btrfs_cpu_key_to_disk(&disk_key
, new_key
);
4471 btrfs_set_item_key(leaf
, &disk_key
, slot
);
4473 new_item
= btrfs_item_nr(slot
);
4475 btrfs_set_item_offset(leaf
, new_item
, orig_offset
);
4476 btrfs_set_item_size(leaf
, new_item
, item_size
- split_offset
);
4478 btrfs_set_item_offset(leaf
, item
,
4479 orig_offset
+ item_size
- split_offset
);
4480 btrfs_set_item_size(leaf
, item
, split_offset
);
4482 btrfs_set_header_nritems(leaf
, nritems
+ 1);
4484 /* write the data for the start of the original item */
4485 write_extent_buffer(leaf
, buf
,
4486 btrfs_item_ptr_offset(leaf
, path
->slots
[0]),
4489 /* write the data for the new item */
4490 write_extent_buffer(leaf
, buf
+ split_offset
,
4491 btrfs_item_ptr_offset(leaf
, slot
),
4492 item_size
- split_offset
);
4493 btrfs_mark_buffer_dirty(leaf
);
4495 BUG_ON(btrfs_leaf_free_space(root
, leaf
) < 0);
4501 * This function splits a single item into two items,
4502 * giving 'new_key' to the new item and splitting the
4503 * old one at split_offset (from the start of the item).
4505 * The path may be released by this operation. After
4506 * the split, the path is pointing to the old item. The
4507 * new item is going to be in the same node as the old one.
4509 * Note, the item being split must be smaller enough to live alone on
4510 * a tree block with room for one extra struct btrfs_item
4512 * This allows us to split the item in place, keeping a lock on the
4513 * leaf the entire time.
4515 int btrfs_split_item(struct btrfs_trans_handle
*trans
,
4516 struct btrfs_root
*root
,
4517 struct btrfs_path
*path
,
4518 struct btrfs_key
*new_key
,
4519 unsigned long split_offset
)
4522 ret
= setup_leaf_for_split(trans
, root
, path
,
4523 sizeof(struct btrfs_item
));
4527 ret
= split_item(trans
, root
, path
, new_key
, split_offset
);
4532 * This function duplicate a item, giving 'new_key' to the new item.
4533 * It guarantees both items live in the same tree leaf and the new item
4534 * is contiguous with the original item.
4536 * This allows us to split file extent in place, keeping a lock on the
4537 * leaf the entire time.
4539 int btrfs_duplicate_item(struct btrfs_trans_handle
*trans
,
4540 struct btrfs_root
*root
,
4541 struct btrfs_path
*path
,
4542 struct btrfs_key
*new_key
)
4544 struct extent_buffer
*leaf
;
4548 leaf
= path
->nodes
[0];
4549 item_size
= btrfs_item_size_nr(leaf
, path
->slots
[0]);
4550 ret
= setup_leaf_for_split(trans
, root
, path
,
4551 item_size
+ sizeof(struct btrfs_item
));
4556 setup_items_for_insert(root
, path
, new_key
, &item_size
,
4557 item_size
, item_size
+
4558 sizeof(struct btrfs_item
), 1);
4559 leaf
= path
->nodes
[0];
4560 memcpy_extent_buffer(leaf
,
4561 btrfs_item_ptr_offset(leaf
, path
->slots
[0]),
4562 btrfs_item_ptr_offset(leaf
, path
->slots
[0] - 1),
4568 * make the item pointed to by the path smaller. new_size indicates
4569 * how small to make it, and from_end tells us if we just chop bytes
4570 * off the end of the item or if we shift the item to chop bytes off
4573 void btrfs_truncate_item(struct btrfs_root
*root
, struct btrfs_path
*path
,
4574 u32 new_size
, int from_end
)
4577 struct extent_buffer
*leaf
;
4578 struct btrfs_item
*item
;
4580 unsigned int data_end
;
4581 unsigned int old_data_start
;
4582 unsigned int old_size
;
4583 unsigned int size_diff
;
4585 struct btrfs_map_token token
;
4587 btrfs_init_map_token(&token
);
4589 leaf
= path
->nodes
[0];
4590 slot
= path
->slots
[0];
4592 old_size
= btrfs_item_size_nr(leaf
, slot
);
4593 if (old_size
== new_size
)
4596 nritems
= btrfs_header_nritems(leaf
);
4597 data_end
= leaf_data_end(root
, leaf
);
4599 old_data_start
= btrfs_item_offset_nr(leaf
, slot
);
4601 size_diff
= old_size
- new_size
;
4604 BUG_ON(slot
>= nritems
);
4607 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4609 /* first correct the data pointers */
4610 for (i
= slot
; i
< nritems
; i
++) {
4612 item
= btrfs_item_nr(i
);
4614 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4615 btrfs_set_token_item_offset(leaf
, item
,
4616 ioff
+ size_diff
, &token
);
4619 /* shift the data */
4621 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4622 data_end
+ size_diff
, btrfs_leaf_data(leaf
) +
4623 data_end
, old_data_start
+ new_size
- data_end
);
4625 struct btrfs_disk_key disk_key
;
4628 btrfs_item_key(leaf
, &disk_key
, slot
);
4630 if (btrfs_disk_key_type(&disk_key
) == BTRFS_EXTENT_DATA_KEY
) {
4632 struct btrfs_file_extent_item
*fi
;
4634 fi
= btrfs_item_ptr(leaf
, slot
,
4635 struct btrfs_file_extent_item
);
4636 fi
= (struct btrfs_file_extent_item
*)(
4637 (unsigned long)fi
- size_diff
);
4639 if (btrfs_file_extent_type(leaf
, fi
) ==
4640 BTRFS_FILE_EXTENT_INLINE
) {
4641 ptr
= btrfs_item_ptr_offset(leaf
, slot
);
4642 memmove_extent_buffer(leaf
, ptr
,
4644 BTRFS_FILE_EXTENT_INLINE_DATA_START
);
4648 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4649 data_end
+ size_diff
, btrfs_leaf_data(leaf
) +
4650 data_end
, old_data_start
- data_end
);
4652 offset
= btrfs_disk_key_offset(&disk_key
);
4653 btrfs_set_disk_key_offset(&disk_key
, offset
+ size_diff
);
4654 btrfs_set_item_key(leaf
, &disk_key
, slot
);
4656 fixup_low_keys(root
->fs_info
, path
, &disk_key
, 1);
4659 item
= btrfs_item_nr(slot
);
4660 btrfs_set_item_size(leaf
, item
, new_size
);
4661 btrfs_mark_buffer_dirty(leaf
);
4663 if (btrfs_leaf_free_space(root
, leaf
) < 0) {
4664 btrfs_print_leaf(root
, leaf
);
4670 * make the item pointed to by the path bigger, data_size is the added size.
4672 void btrfs_extend_item(struct btrfs_root
*root
, struct btrfs_path
*path
,
4676 struct extent_buffer
*leaf
;
4677 struct btrfs_item
*item
;
4679 unsigned int data_end
;
4680 unsigned int old_data
;
4681 unsigned int old_size
;
4683 struct btrfs_map_token token
;
4685 btrfs_init_map_token(&token
);
4687 leaf
= path
->nodes
[0];
4689 nritems
= btrfs_header_nritems(leaf
);
4690 data_end
= leaf_data_end(root
, leaf
);
4692 if (btrfs_leaf_free_space(root
, leaf
) < data_size
) {
4693 btrfs_print_leaf(root
, leaf
);
4696 slot
= path
->slots
[0];
4697 old_data
= btrfs_item_end_nr(leaf
, slot
);
4700 if (slot
>= nritems
) {
4701 btrfs_print_leaf(root
, leaf
);
4702 btrfs_crit(root
->fs_info
, "slot %d too large, nritems %d",
4708 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4710 /* first correct the data pointers */
4711 for (i
= slot
; i
< nritems
; i
++) {
4713 item
= btrfs_item_nr(i
);
4715 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4716 btrfs_set_token_item_offset(leaf
, item
,
4717 ioff
- data_size
, &token
);
4720 /* shift the data */
4721 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4722 data_end
- data_size
, btrfs_leaf_data(leaf
) +
4723 data_end
, old_data
- data_end
);
4725 data_end
= old_data
;
4726 old_size
= btrfs_item_size_nr(leaf
, slot
);
4727 item
= btrfs_item_nr(slot
);
4728 btrfs_set_item_size(leaf
, item
, old_size
+ data_size
);
4729 btrfs_mark_buffer_dirty(leaf
);
4731 if (btrfs_leaf_free_space(root
, leaf
) < 0) {
4732 btrfs_print_leaf(root
, leaf
);
4738 * this is a helper for btrfs_insert_empty_items, the main goal here is
4739 * to save stack depth by doing the bulk of the work in a function
4740 * that doesn't call btrfs_search_slot
4742 void setup_items_for_insert(struct btrfs_root
*root
, struct btrfs_path
*path
,
4743 struct btrfs_key
*cpu_key
, u32
*data_size
,
4744 u32 total_data
, u32 total_size
, int nr
)
4746 struct btrfs_item
*item
;
4749 unsigned int data_end
;
4750 struct btrfs_disk_key disk_key
;
4751 struct extent_buffer
*leaf
;
4753 struct btrfs_map_token token
;
4755 if (path
->slots
[0] == 0) {
4756 btrfs_cpu_key_to_disk(&disk_key
, cpu_key
);
4757 fixup_low_keys(root
->fs_info
, path
, &disk_key
, 1);
4759 btrfs_unlock_up_safe(path
, 1);
4761 btrfs_init_map_token(&token
);
4763 leaf
= path
->nodes
[0];
4764 slot
= path
->slots
[0];
4766 nritems
= btrfs_header_nritems(leaf
);
4767 data_end
= leaf_data_end(root
, leaf
);
4769 if (btrfs_leaf_free_space(root
, leaf
) < total_size
) {
4770 btrfs_print_leaf(root
, leaf
);
4771 btrfs_crit(root
->fs_info
,
4772 "not enough freespace need %u have %d",
4773 total_size
, btrfs_leaf_free_space(root
, leaf
));
4777 if (slot
!= nritems
) {
4778 unsigned int old_data
= btrfs_item_end_nr(leaf
, slot
);
4780 if (old_data
< data_end
) {
4781 btrfs_print_leaf(root
, leaf
);
4782 btrfs_crit(root
->fs_info
,
4783 "slot %d old_data %d data_end %d",
4784 slot
, old_data
, data_end
);
4788 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4790 /* first correct the data pointers */
4791 for (i
= slot
; i
< nritems
; i
++) {
4794 item
= btrfs_item_nr(i
);
4795 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4796 btrfs_set_token_item_offset(leaf
, item
,
4797 ioff
- total_data
, &token
);
4799 /* shift the items */
4800 memmove_extent_buffer(leaf
, btrfs_item_nr_offset(slot
+ nr
),
4801 btrfs_item_nr_offset(slot
),
4802 (nritems
- slot
) * sizeof(struct btrfs_item
));
4804 /* shift the data */
4805 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4806 data_end
- total_data
, btrfs_leaf_data(leaf
) +
4807 data_end
, old_data
- data_end
);
4808 data_end
= old_data
;
4811 /* setup the item for the new data */
4812 for (i
= 0; i
< nr
; i
++) {
4813 btrfs_cpu_key_to_disk(&disk_key
, cpu_key
+ i
);
4814 btrfs_set_item_key(leaf
, &disk_key
, slot
+ i
);
4815 item
= btrfs_item_nr(slot
+ i
);
4816 btrfs_set_token_item_offset(leaf
, item
,
4817 data_end
- data_size
[i
], &token
);
4818 data_end
-= data_size
[i
];
4819 btrfs_set_token_item_size(leaf
, item
, data_size
[i
], &token
);
4822 btrfs_set_header_nritems(leaf
, nritems
+ nr
);
4823 btrfs_mark_buffer_dirty(leaf
);
4825 if (btrfs_leaf_free_space(root
, leaf
) < 0) {
4826 btrfs_print_leaf(root
, leaf
);
4832 * Given a key and some data, insert items into the tree.
4833 * This does all the path init required, making room in the tree if needed.
4835 int btrfs_insert_empty_items(struct btrfs_trans_handle
*trans
,
4836 struct btrfs_root
*root
,
4837 struct btrfs_path
*path
,
4838 struct btrfs_key
*cpu_key
, u32
*data_size
,
4847 for (i
= 0; i
< nr
; i
++)
4848 total_data
+= data_size
[i
];
4850 total_size
= total_data
+ (nr
* sizeof(struct btrfs_item
));
4851 ret
= btrfs_search_slot(trans
, root
, cpu_key
, path
, total_size
, 1);
4857 slot
= path
->slots
[0];
4860 setup_items_for_insert(root
, path
, cpu_key
, data_size
,
4861 total_data
, total_size
, nr
);
4866 * Given a key and some data, insert an item into the tree.
4867 * This does all the path init required, making room in the tree if needed.
4869 int btrfs_insert_item(struct btrfs_trans_handle
*trans
, struct btrfs_root
4870 *root
, struct btrfs_key
*cpu_key
, void *data
, u32
4874 struct btrfs_path
*path
;
4875 struct extent_buffer
*leaf
;
4878 path
= btrfs_alloc_path();
4881 ret
= btrfs_insert_empty_item(trans
, root
, path
, cpu_key
, data_size
);
4883 leaf
= path
->nodes
[0];
4884 ptr
= btrfs_item_ptr_offset(leaf
, path
->slots
[0]);
4885 write_extent_buffer(leaf
, data
, ptr
, data_size
);
4886 btrfs_mark_buffer_dirty(leaf
);
4888 btrfs_free_path(path
);
4893 * delete the pointer from a given node.
4895 * the tree should have been previously balanced so the deletion does not
4898 static void del_ptr(struct btrfs_root
*root
, struct btrfs_path
*path
,
4899 int level
, int slot
)
4901 struct extent_buffer
*parent
= path
->nodes
[level
];
4905 nritems
= btrfs_header_nritems(parent
);
4906 if (slot
!= nritems
- 1) {
4908 tree_mod_log_eb_move(root
->fs_info
, parent
, slot
,
4909 slot
+ 1, nritems
- slot
- 1);
4910 memmove_extent_buffer(parent
,
4911 btrfs_node_key_ptr_offset(slot
),
4912 btrfs_node_key_ptr_offset(slot
+ 1),
4913 sizeof(struct btrfs_key_ptr
) *
4914 (nritems
- slot
- 1));
4916 ret
= tree_mod_log_insert_key(root
->fs_info
, parent
, slot
,
4917 MOD_LOG_KEY_REMOVE
, GFP_NOFS
);
4922 btrfs_set_header_nritems(parent
, nritems
);
4923 if (nritems
== 0 && parent
== root
->node
) {
4924 BUG_ON(btrfs_header_level(root
->node
) != 1);
4925 /* just turn the root into a leaf and break */
4926 btrfs_set_header_level(root
->node
, 0);
4927 } else if (slot
== 0) {
4928 struct btrfs_disk_key disk_key
;
4930 btrfs_node_key(parent
, &disk_key
, 0);
4931 fixup_low_keys(root
->fs_info
, path
, &disk_key
, level
+ 1);
4933 btrfs_mark_buffer_dirty(parent
);
4937 * a helper function to delete the leaf pointed to by path->slots[1] and
4940 * This deletes the pointer in path->nodes[1] and frees the leaf
4941 * block extent. zero is returned if it all worked out, < 0 otherwise.
4943 * The path must have already been setup for deleting the leaf, including
4944 * all the proper balancing. path->nodes[1] must be locked.
4946 static noinline
void btrfs_del_leaf(struct btrfs_trans_handle
*trans
,
4947 struct btrfs_root
*root
,
4948 struct btrfs_path
*path
,
4949 struct extent_buffer
*leaf
)
4951 WARN_ON(btrfs_header_generation(leaf
) != trans
->transid
);
4952 del_ptr(root
, path
, 1, path
->slots
[1]);
4955 * btrfs_free_extent is expensive, we want to make sure we
4956 * aren't holding any locks when we call it
4958 btrfs_unlock_up_safe(path
, 0);
4960 root_sub_used(root
, leaf
->len
);
4962 extent_buffer_get(leaf
);
4963 btrfs_free_tree_block(trans
, root
, leaf
, 0, 1);
4964 free_extent_buffer_stale(leaf
);
4967 * delete the item at the leaf level in path. If that empties
4968 * the leaf, remove it from the tree
4970 int btrfs_del_items(struct btrfs_trans_handle
*trans
, struct btrfs_root
*root
,
4971 struct btrfs_path
*path
, int slot
, int nr
)
4973 struct extent_buffer
*leaf
;
4974 struct btrfs_item
*item
;
4981 struct btrfs_map_token token
;
4983 btrfs_init_map_token(&token
);
4985 leaf
= path
->nodes
[0];
4986 last_off
= btrfs_item_offset_nr(leaf
, slot
+ nr
- 1);
4988 for (i
= 0; i
< nr
; i
++)
4989 dsize
+= btrfs_item_size_nr(leaf
, slot
+ i
);
4991 nritems
= btrfs_header_nritems(leaf
);
4993 if (slot
+ nr
!= nritems
) {
4994 int data_end
= leaf_data_end(root
, leaf
);
4996 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4998 btrfs_leaf_data(leaf
) + data_end
,
4999 last_off
- data_end
);
5001 for (i
= slot
+ nr
; i
< nritems
; i
++) {
5004 item
= btrfs_item_nr(i
);
5005 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
5006 btrfs_set_token_item_offset(leaf
, item
,
5007 ioff
+ dsize
, &token
);
5010 memmove_extent_buffer(leaf
, btrfs_item_nr_offset(slot
),
5011 btrfs_item_nr_offset(slot
+ nr
),
5012 sizeof(struct btrfs_item
) *
5013 (nritems
- slot
- nr
));
5015 btrfs_set_header_nritems(leaf
, nritems
- nr
);
5018 /* delete the leaf if we've emptied it */
5020 if (leaf
== root
->node
) {
5021 btrfs_set_header_level(leaf
, 0);
5023 btrfs_set_path_blocking(path
);
5024 clean_tree_block(trans
, root
->fs_info
, leaf
);
5025 btrfs_del_leaf(trans
, root
, path
, leaf
);
5028 int used
= leaf_space_used(leaf
, 0, nritems
);
5030 struct btrfs_disk_key disk_key
;
5032 btrfs_item_key(leaf
, &disk_key
, 0);
5033 fixup_low_keys(root
->fs_info
, path
, &disk_key
, 1);
5036 /* delete the leaf if it is mostly empty */
5037 if (used
< BTRFS_LEAF_DATA_SIZE(root
) / 3) {
5038 /* push_leaf_left fixes the path.
5039 * make sure the path still points to our leaf
5040 * for possible call to del_ptr below
5042 slot
= path
->slots
[1];
5043 extent_buffer_get(leaf
);
5045 btrfs_set_path_blocking(path
);
5046 wret
= push_leaf_left(trans
, root
, path
, 1, 1,
5048 if (wret
< 0 && wret
!= -ENOSPC
)
5051 if (path
->nodes
[0] == leaf
&&
5052 btrfs_header_nritems(leaf
)) {
5053 wret
= push_leaf_right(trans
, root
, path
, 1,
5055 if (wret
< 0 && wret
!= -ENOSPC
)
5059 if (btrfs_header_nritems(leaf
) == 0) {
5060 path
->slots
[1] = slot
;
5061 btrfs_del_leaf(trans
, root
, path
, leaf
);
5062 free_extent_buffer(leaf
);
5065 /* if we're still in the path, make sure
5066 * we're dirty. Otherwise, one of the
5067 * push_leaf functions must have already
5068 * dirtied this buffer
5070 if (path
->nodes
[0] == leaf
)
5071 btrfs_mark_buffer_dirty(leaf
);
5072 free_extent_buffer(leaf
);
5075 btrfs_mark_buffer_dirty(leaf
);
5082 * search the tree again to find a leaf with lesser keys
5083 * returns 0 if it found something or 1 if there are no lesser leaves.
5084 * returns < 0 on io errors.
5086 * This may release the path, and so you may lose any locks held at the
5089 int btrfs_prev_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
)
5091 struct btrfs_key key
;
5092 struct btrfs_disk_key found_key
;
5095 btrfs_item_key_to_cpu(path
->nodes
[0], &key
, 0);
5097 if (key
.offset
> 0) {
5099 } else if (key
.type
> 0) {
5101 key
.offset
= (u64
)-1;
5102 } else if (key
.objectid
> 0) {
5105 key
.offset
= (u64
)-1;
5110 btrfs_release_path(path
);
5111 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
5114 btrfs_item_key(path
->nodes
[0], &found_key
, 0);
5115 ret
= comp_keys(&found_key
, &key
);
5117 * We might have had an item with the previous key in the tree right
5118 * before we released our path. And after we released our path, that
5119 * item might have been pushed to the first slot (0) of the leaf we
5120 * were holding due to a tree balance. Alternatively, an item with the
5121 * previous key can exist as the only element of a leaf (big fat item).
5122 * Therefore account for these 2 cases, so that our callers (like
5123 * btrfs_previous_item) don't miss an existing item with a key matching
5124 * the previous key we computed above.
5132 * A helper function to walk down the tree starting at min_key, and looking
5133 * for nodes or leaves that are have a minimum transaction id.
5134 * This is used by the btree defrag code, and tree logging
5136 * This does not cow, but it does stuff the starting key it finds back
5137 * into min_key, so you can call btrfs_search_slot with cow=1 on the
5138 * key and get a writable path.
5140 * This does lock as it descends, and path->keep_locks should be set
5141 * to 1 by the caller.
5143 * This honors path->lowest_level to prevent descent past a given level
5146 * min_trans indicates the oldest transaction that you are interested
5147 * in walking through. Any nodes or leaves older than min_trans are
5148 * skipped over (without reading them).
5150 * returns zero if something useful was found, < 0 on error and 1 if there
5151 * was nothing in the tree that matched the search criteria.
5153 int btrfs_search_forward(struct btrfs_root
*root
, struct btrfs_key
*min_key
,
5154 struct btrfs_path
*path
,
5157 struct extent_buffer
*cur
;
5158 struct btrfs_key found_key
;
5164 int keep_locks
= path
->keep_locks
;
5166 path
->keep_locks
= 1;
5168 cur
= btrfs_read_lock_root_node(root
);
5169 level
= btrfs_header_level(cur
);
5170 WARN_ON(path
->nodes
[level
]);
5171 path
->nodes
[level
] = cur
;
5172 path
->locks
[level
] = BTRFS_READ_LOCK
;
5174 if (btrfs_header_generation(cur
) < min_trans
) {
5179 nritems
= btrfs_header_nritems(cur
);
5180 level
= btrfs_header_level(cur
);
5181 sret
= bin_search(cur
, min_key
, level
, &slot
);
5183 /* at the lowest level, we're done, setup the path and exit */
5184 if (level
== path
->lowest_level
) {
5185 if (slot
>= nritems
)
5188 path
->slots
[level
] = slot
;
5189 btrfs_item_key_to_cpu(cur
, &found_key
, slot
);
5192 if (sret
&& slot
> 0)
5195 * check this node pointer against the min_trans parameters.
5196 * If it is too old, old, skip to the next one.
5198 while (slot
< nritems
) {
5201 gen
= btrfs_node_ptr_generation(cur
, slot
);
5202 if (gen
< min_trans
) {
5210 * we didn't find a candidate key in this node, walk forward
5211 * and find another one
5213 if (slot
>= nritems
) {
5214 path
->slots
[level
] = slot
;
5215 btrfs_set_path_blocking(path
);
5216 sret
= btrfs_find_next_key(root
, path
, min_key
, level
,
5219 btrfs_release_path(path
);
5225 /* save our key for returning back */
5226 btrfs_node_key_to_cpu(cur
, &found_key
, slot
);
5227 path
->slots
[level
] = slot
;
5228 if (level
== path
->lowest_level
) {
5232 btrfs_set_path_blocking(path
);
5233 cur
= read_node_slot(root
, cur
, slot
);
5239 btrfs_tree_read_lock(cur
);
5241 path
->locks
[level
- 1] = BTRFS_READ_LOCK
;
5242 path
->nodes
[level
- 1] = cur
;
5243 unlock_up(path
, level
, 1, 0, NULL
);
5244 btrfs_clear_path_blocking(path
, NULL
, 0);
5247 path
->keep_locks
= keep_locks
;
5249 btrfs_unlock_up_safe(path
, path
->lowest_level
+ 1);
5250 btrfs_set_path_blocking(path
);
5251 memcpy(min_key
, &found_key
, sizeof(found_key
));
5256 static int tree_move_down(struct btrfs_root
*root
,
5257 struct btrfs_path
*path
,
5258 int *level
, int root_level
)
5260 struct extent_buffer
*eb
;
5262 BUG_ON(*level
== 0);
5263 eb
= read_node_slot(root
, path
->nodes
[*level
], path
->slots
[*level
]);
5267 path
->nodes
[*level
- 1] = eb
;
5268 path
->slots
[*level
- 1] = 0;
5273 static int tree_move_next_or_upnext(struct btrfs_root
*root
,
5274 struct btrfs_path
*path
,
5275 int *level
, int root_level
)
5279 nritems
= btrfs_header_nritems(path
->nodes
[*level
]);
5281 path
->slots
[*level
]++;
5283 while (path
->slots
[*level
] >= nritems
) {
5284 if (*level
== root_level
)
5288 path
->slots
[*level
] = 0;
5289 free_extent_buffer(path
->nodes
[*level
]);
5290 path
->nodes
[*level
] = NULL
;
5292 path
->slots
[*level
]++;
5294 nritems
= btrfs_header_nritems(path
->nodes
[*level
]);
5301 * Returns 1 if it had to move up and next. 0 is returned if it moved only next
5304 static int tree_advance(struct btrfs_root
*root
,
5305 struct btrfs_path
*path
,
5306 int *level
, int root_level
,
5308 struct btrfs_key
*key
)
5312 if (*level
== 0 || !allow_down
) {
5313 ret
= tree_move_next_or_upnext(root
, path
, level
, root_level
);
5315 ret
= tree_move_down(root
, path
, level
, root_level
);
5319 btrfs_item_key_to_cpu(path
->nodes
[*level
], key
,
5320 path
->slots
[*level
]);
5322 btrfs_node_key_to_cpu(path
->nodes
[*level
], key
,
5323 path
->slots
[*level
]);
5328 static int tree_compare_item(struct btrfs_root
*left_root
,
5329 struct btrfs_path
*left_path
,
5330 struct btrfs_path
*right_path
,
5335 unsigned long off1
, off2
;
5337 len1
= btrfs_item_size_nr(left_path
->nodes
[0], left_path
->slots
[0]);
5338 len2
= btrfs_item_size_nr(right_path
->nodes
[0], right_path
->slots
[0]);
5342 off1
= btrfs_item_ptr_offset(left_path
->nodes
[0], left_path
->slots
[0]);
5343 off2
= btrfs_item_ptr_offset(right_path
->nodes
[0],
5344 right_path
->slots
[0]);
5346 read_extent_buffer(left_path
->nodes
[0], tmp_buf
, off1
, len1
);
5348 cmp
= memcmp_extent_buffer(right_path
->nodes
[0], tmp_buf
, off2
, len1
);
5355 #define ADVANCE_ONLY_NEXT -1
5358 * This function compares two trees and calls the provided callback for
5359 * every changed/new/deleted item it finds.
5360 * If shared tree blocks are encountered, whole subtrees are skipped, making
5361 * the compare pretty fast on snapshotted subvolumes.
5363 * This currently works on commit roots only. As commit roots are read only,
5364 * we don't do any locking. The commit roots are protected with transactions.
5365 * Transactions are ended and rejoined when a commit is tried in between.
5367 * This function checks for modifications done to the trees while comparing.
5368 * If it detects a change, it aborts immediately.
5370 int btrfs_compare_trees(struct btrfs_root
*left_root
,
5371 struct btrfs_root
*right_root
,
5372 btrfs_changed_cb_t changed_cb
, void *ctx
)
5376 struct btrfs_path
*left_path
= NULL
;
5377 struct btrfs_path
*right_path
= NULL
;
5378 struct btrfs_key left_key
;
5379 struct btrfs_key right_key
;
5380 char *tmp_buf
= NULL
;
5381 int left_root_level
;
5382 int right_root_level
;
5385 int left_end_reached
;
5386 int right_end_reached
;
5394 left_path
= btrfs_alloc_path();
5399 right_path
= btrfs_alloc_path();
5405 tmp_buf
= kmalloc(left_root
->nodesize
, GFP_KERNEL
| __GFP_NOWARN
);
5407 tmp_buf
= vmalloc(left_root
->nodesize
);
5414 left_path
->search_commit_root
= 1;
5415 left_path
->skip_locking
= 1;
5416 right_path
->search_commit_root
= 1;
5417 right_path
->skip_locking
= 1;
5420 * Strategy: Go to the first items of both trees. Then do
5422 * If both trees are at level 0
5423 * Compare keys of current items
5424 * If left < right treat left item as new, advance left tree
5426 * If left > right treat right item as deleted, advance right tree
5428 * If left == right do deep compare of items, treat as changed if
5429 * needed, advance both trees and repeat
5430 * If both trees are at the same level but not at level 0
5431 * Compare keys of current nodes/leafs
5432 * If left < right advance left tree and repeat
5433 * If left > right advance right tree and repeat
5434 * If left == right compare blockptrs of the next nodes/leafs
5435 * If they match advance both trees but stay at the same level
5437 * If they don't match advance both trees while allowing to go
5439 * If tree levels are different
5440 * Advance the tree that needs it and repeat
5442 * Advancing a tree means:
5443 * If we are at level 0, try to go to the next slot. If that's not
5444 * possible, go one level up and repeat. Stop when we found a level
5445 * where we could go to the next slot. We may at this point be on a
5448 * If we are not at level 0 and not on shared tree blocks, go one
5451 * If we are not at level 0 and on shared tree blocks, go one slot to
5452 * the right if possible or go up and right.
5455 down_read(&left_root
->fs_info
->commit_root_sem
);
5456 left_level
= btrfs_header_level(left_root
->commit_root
);
5457 left_root_level
= left_level
;
5458 left_path
->nodes
[left_level
] = left_root
->commit_root
;
5459 extent_buffer_get(left_path
->nodes
[left_level
]);
5461 right_level
= btrfs_header_level(right_root
->commit_root
);
5462 right_root_level
= right_level
;
5463 right_path
->nodes
[right_level
] = right_root
->commit_root
;
5464 extent_buffer_get(right_path
->nodes
[right_level
]);
5465 up_read(&left_root
->fs_info
->commit_root_sem
);
5467 if (left_level
== 0)
5468 btrfs_item_key_to_cpu(left_path
->nodes
[left_level
],
5469 &left_key
, left_path
->slots
[left_level
]);
5471 btrfs_node_key_to_cpu(left_path
->nodes
[left_level
],
5472 &left_key
, left_path
->slots
[left_level
]);
5473 if (right_level
== 0)
5474 btrfs_item_key_to_cpu(right_path
->nodes
[right_level
],
5475 &right_key
, right_path
->slots
[right_level
]);
5477 btrfs_node_key_to_cpu(right_path
->nodes
[right_level
],
5478 &right_key
, right_path
->slots
[right_level
]);
5480 left_end_reached
= right_end_reached
= 0;
5481 advance_left
= advance_right
= 0;
5484 if (advance_left
&& !left_end_reached
) {
5485 ret
= tree_advance(left_root
, left_path
, &left_level
,
5487 advance_left
!= ADVANCE_ONLY_NEXT
,
5490 left_end_reached
= ADVANCE
;
5495 if (advance_right
&& !right_end_reached
) {
5496 ret
= tree_advance(right_root
, right_path
, &right_level
,
5498 advance_right
!= ADVANCE_ONLY_NEXT
,
5501 right_end_reached
= ADVANCE
;
5507 if (left_end_reached
&& right_end_reached
) {
5510 } else if (left_end_reached
) {
5511 if (right_level
== 0) {
5512 ret
= changed_cb(left_root
, right_root
,
5513 left_path
, right_path
,
5515 BTRFS_COMPARE_TREE_DELETED
,
5520 advance_right
= ADVANCE
;
5522 } else if (right_end_reached
) {
5523 if (left_level
== 0) {
5524 ret
= changed_cb(left_root
, right_root
,
5525 left_path
, right_path
,
5527 BTRFS_COMPARE_TREE_NEW
,
5532 advance_left
= ADVANCE
;
5536 if (left_level
== 0 && right_level
== 0) {
5537 cmp
= btrfs_comp_cpu_keys(&left_key
, &right_key
);
5539 ret
= changed_cb(left_root
, right_root
,
5540 left_path
, right_path
,
5542 BTRFS_COMPARE_TREE_NEW
,
5546 advance_left
= ADVANCE
;
5547 } else if (cmp
> 0) {
5548 ret
= changed_cb(left_root
, right_root
,
5549 left_path
, right_path
,
5551 BTRFS_COMPARE_TREE_DELETED
,
5555 advance_right
= ADVANCE
;
5557 enum btrfs_compare_tree_result result
;
5559 WARN_ON(!extent_buffer_uptodate(left_path
->nodes
[0]));
5560 ret
= tree_compare_item(left_root
, left_path
,
5561 right_path
, tmp_buf
);
5563 result
= BTRFS_COMPARE_TREE_CHANGED
;
5565 result
= BTRFS_COMPARE_TREE_SAME
;
5566 ret
= changed_cb(left_root
, right_root
,
5567 left_path
, right_path
,
5568 &left_key
, result
, ctx
);
5571 advance_left
= ADVANCE
;
5572 advance_right
= ADVANCE
;
5574 } else if (left_level
== right_level
) {
5575 cmp
= btrfs_comp_cpu_keys(&left_key
, &right_key
);
5577 advance_left
= ADVANCE
;
5578 } else if (cmp
> 0) {
5579 advance_right
= ADVANCE
;
5581 left_blockptr
= btrfs_node_blockptr(
5582 left_path
->nodes
[left_level
],
5583 left_path
->slots
[left_level
]);
5584 right_blockptr
= btrfs_node_blockptr(
5585 right_path
->nodes
[right_level
],
5586 right_path
->slots
[right_level
]);
5587 left_gen
= btrfs_node_ptr_generation(
5588 left_path
->nodes
[left_level
],
5589 left_path
->slots
[left_level
]);
5590 right_gen
= btrfs_node_ptr_generation(
5591 right_path
->nodes
[right_level
],
5592 right_path
->slots
[right_level
]);
5593 if (left_blockptr
== right_blockptr
&&
5594 left_gen
== right_gen
) {
5596 * As we're on a shared block, don't
5597 * allow to go deeper.
5599 advance_left
= ADVANCE_ONLY_NEXT
;
5600 advance_right
= ADVANCE_ONLY_NEXT
;
5602 advance_left
= ADVANCE
;
5603 advance_right
= ADVANCE
;
5606 } else if (left_level
< right_level
) {
5607 advance_right
= ADVANCE
;
5609 advance_left
= ADVANCE
;
5614 btrfs_free_path(left_path
);
5615 btrfs_free_path(right_path
);
5621 * this is similar to btrfs_next_leaf, but does not try to preserve
5622 * and fixup the path. It looks for and returns the next key in the
5623 * tree based on the current path and the min_trans parameters.
5625 * 0 is returned if another key is found, < 0 if there are any errors
5626 * and 1 is returned if there are no higher keys in the tree
5628 * path->keep_locks should be set to 1 on the search made before
5629 * calling this function.
5631 int btrfs_find_next_key(struct btrfs_root
*root
, struct btrfs_path
*path
,
5632 struct btrfs_key
*key
, int level
, u64 min_trans
)
5635 struct extent_buffer
*c
;
5637 WARN_ON(!path
->keep_locks
);
5638 while (level
< BTRFS_MAX_LEVEL
) {
5639 if (!path
->nodes
[level
])
5642 slot
= path
->slots
[level
] + 1;
5643 c
= path
->nodes
[level
];
5645 if (slot
>= btrfs_header_nritems(c
)) {
5648 struct btrfs_key cur_key
;
5649 if (level
+ 1 >= BTRFS_MAX_LEVEL
||
5650 !path
->nodes
[level
+ 1])
5653 if (path
->locks
[level
+ 1]) {
5658 slot
= btrfs_header_nritems(c
) - 1;
5660 btrfs_item_key_to_cpu(c
, &cur_key
, slot
);
5662 btrfs_node_key_to_cpu(c
, &cur_key
, slot
);
5664 orig_lowest
= path
->lowest_level
;
5665 btrfs_release_path(path
);
5666 path
->lowest_level
= level
;
5667 ret
= btrfs_search_slot(NULL
, root
, &cur_key
, path
,
5669 path
->lowest_level
= orig_lowest
;
5673 c
= path
->nodes
[level
];
5674 slot
= path
->slots
[level
];
5681 btrfs_item_key_to_cpu(c
, key
, slot
);
5683 u64 gen
= btrfs_node_ptr_generation(c
, slot
);
5685 if (gen
< min_trans
) {
5689 btrfs_node_key_to_cpu(c
, key
, slot
);
5697 * search the tree again to find a leaf with greater keys
5698 * returns 0 if it found something or 1 if there are no greater leaves.
5699 * returns < 0 on io errors.
5701 int btrfs_next_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
)
5703 return btrfs_next_old_leaf(root
, path
, 0);
5706 int btrfs_next_old_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
,
5711 struct extent_buffer
*c
;
5712 struct extent_buffer
*next
;
5713 struct btrfs_key key
;
5716 int old_spinning
= path
->leave_spinning
;
5717 int next_rw_lock
= 0;
5719 nritems
= btrfs_header_nritems(path
->nodes
[0]);
5723 btrfs_item_key_to_cpu(path
->nodes
[0], &key
, nritems
- 1);
5728 btrfs_release_path(path
);
5730 path
->keep_locks
= 1;
5731 path
->leave_spinning
= 1;
5734 ret
= btrfs_search_old_slot(root
, &key
, path
, time_seq
);
5736 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
5737 path
->keep_locks
= 0;
5742 nritems
= btrfs_header_nritems(path
->nodes
[0]);
5744 * by releasing the path above we dropped all our locks. A balance
5745 * could have added more items next to the key that used to be
5746 * at the very end of the block. So, check again here and
5747 * advance the path if there are now more items available.
5749 if (nritems
> 0 && path
->slots
[0] < nritems
- 1) {
5756 * So the above check misses one case:
5757 * - after releasing the path above, someone has removed the item that
5758 * used to be at the very end of the block, and balance between leafs
5759 * gets another one with bigger key.offset to replace it.
5761 * This one should be returned as well, or we can get leaf corruption
5762 * later(esp. in __btrfs_drop_extents()).
5764 * And a bit more explanation about this check,
5765 * with ret > 0, the key isn't found, the path points to the slot
5766 * where it should be inserted, so the path->slots[0] item must be the
5769 if (nritems
> 0 && ret
> 0 && path
->slots
[0] == nritems
- 1) {
5774 while (level
< BTRFS_MAX_LEVEL
) {
5775 if (!path
->nodes
[level
]) {
5780 slot
= path
->slots
[level
] + 1;
5781 c
= path
->nodes
[level
];
5782 if (slot
>= btrfs_header_nritems(c
)) {
5784 if (level
== BTRFS_MAX_LEVEL
) {
5792 btrfs_tree_unlock_rw(next
, next_rw_lock
);
5793 free_extent_buffer(next
);
5797 next_rw_lock
= path
->locks
[level
];
5798 ret
= read_block_for_search(NULL
, root
, path
, &next
, level
,
5804 btrfs_release_path(path
);
5808 if (!path
->skip_locking
) {
5809 ret
= btrfs_try_tree_read_lock(next
);
5810 if (!ret
&& time_seq
) {
5812 * If we don't get the lock, we may be racing
5813 * with push_leaf_left, holding that lock while
5814 * itself waiting for the leaf we've currently
5815 * locked. To solve this situation, we give up
5816 * on our lock and cycle.
5818 free_extent_buffer(next
);
5819 btrfs_release_path(path
);
5824 btrfs_set_path_blocking(path
);
5825 btrfs_tree_read_lock(next
);
5826 btrfs_clear_path_blocking(path
, next
,
5829 next_rw_lock
= BTRFS_READ_LOCK
;
5833 path
->slots
[level
] = slot
;
5836 c
= path
->nodes
[level
];
5837 if (path
->locks
[level
])
5838 btrfs_tree_unlock_rw(c
, path
->locks
[level
]);
5840 free_extent_buffer(c
);
5841 path
->nodes
[level
] = next
;
5842 path
->slots
[level
] = 0;
5843 if (!path
->skip_locking
)
5844 path
->locks
[level
] = next_rw_lock
;
5848 ret
= read_block_for_search(NULL
, root
, path
, &next
, level
,
5854 btrfs_release_path(path
);
5858 if (!path
->skip_locking
) {
5859 ret
= btrfs_try_tree_read_lock(next
);
5861 btrfs_set_path_blocking(path
);
5862 btrfs_tree_read_lock(next
);
5863 btrfs_clear_path_blocking(path
, next
,
5866 next_rw_lock
= BTRFS_READ_LOCK
;
5871 unlock_up(path
, 0, 1, 0, NULL
);
5872 path
->leave_spinning
= old_spinning
;
5874 btrfs_set_path_blocking(path
);
5880 * this uses btrfs_prev_leaf to walk backwards in the tree, and keeps
5881 * searching until it gets past min_objectid or finds an item of 'type'
5883 * returns 0 if something is found, 1 if nothing was found and < 0 on error
5885 int btrfs_previous_item(struct btrfs_root
*root
,
5886 struct btrfs_path
*path
, u64 min_objectid
,
5889 struct btrfs_key found_key
;
5890 struct extent_buffer
*leaf
;
5895 if (path
->slots
[0] == 0) {
5896 btrfs_set_path_blocking(path
);
5897 ret
= btrfs_prev_leaf(root
, path
);
5903 leaf
= path
->nodes
[0];
5904 nritems
= btrfs_header_nritems(leaf
);
5907 if (path
->slots
[0] == nritems
)
5910 btrfs_item_key_to_cpu(leaf
, &found_key
, path
->slots
[0]);
5911 if (found_key
.objectid
< min_objectid
)
5913 if (found_key
.type
== type
)
5915 if (found_key
.objectid
== min_objectid
&&
5916 found_key
.type
< type
)
5923 * search in extent tree to find a previous Metadata/Data extent item with
5926 * returns 0 if something is found, 1 if nothing was found and < 0 on error
5928 int btrfs_previous_extent_item(struct btrfs_root
*root
,
5929 struct btrfs_path
*path
, u64 min_objectid
)
5931 struct btrfs_key found_key
;
5932 struct extent_buffer
*leaf
;
5937 if (path
->slots
[0] == 0) {
5938 btrfs_set_path_blocking(path
);
5939 ret
= btrfs_prev_leaf(root
, path
);
5945 leaf
= path
->nodes
[0];
5946 nritems
= btrfs_header_nritems(leaf
);
5949 if (path
->slots
[0] == nritems
)
5952 btrfs_item_key_to_cpu(leaf
, &found_key
, path
->slots
[0]);
5953 if (found_key
.objectid
< min_objectid
)
5955 if (found_key
.type
== BTRFS_EXTENT_ITEM_KEY
||
5956 found_key
.type
== BTRFS_METADATA_ITEM_KEY
)
5958 if (found_key
.objectid
== min_objectid
&&
5959 found_key
.type
< BTRFS_EXTENT_ITEM_KEY
)