2 * Copyright (C) 2007,2008 Oracle. All rights reserved.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
19 #include <linux/sched.h>
20 #include <linux/slab.h>
21 #include <linux/rbtree.h>
24 #include "transaction.h"
25 #include "print-tree.h"
28 static int split_node(struct btrfs_trans_handle
*trans
, struct btrfs_root
29 *root
, struct btrfs_path
*path
, int level
);
30 static int split_leaf(struct btrfs_trans_handle
*trans
, struct btrfs_root
31 *root
, struct btrfs_key
*ins_key
,
32 struct btrfs_path
*path
, int data_size
, int extend
);
33 static int push_node_left(struct btrfs_trans_handle
*trans
,
34 struct btrfs_root
*root
, struct extent_buffer
*dst
,
35 struct extent_buffer
*src
, int empty
);
36 static int balance_node_right(struct btrfs_trans_handle
*trans
,
37 struct btrfs_root
*root
,
38 struct extent_buffer
*dst_buf
,
39 struct extent_buffer
*src_buf
);
40 static void del_ptr(struct btrfs_root
*root
, struct btrfs_path
*path
,
42 static int tree_mod_log_free_eb(struct btrfs_fs_info
*fs_info
,
43 struct extent_buffer
*eb
);
45 struct btrfs_path
*btrfs_alloc_path(void)
47 struct btrfs_path
*path
;
48 path
= kmem_cache_zalloc(btrfs_path_cachep
, GFP_NOFS
);
53 * set all locked nodes in the path to blocking locks. This should
54 * be done before scheduling
56 noinline
void btrfs_set_path_blocking(struct btrfs_path
*p
)
59 for (i
= 0; i
< BTRFS_MAX_LEVEL
; i
++) {
60 if (!p
->nodes
[i
] || !p
->locks
[i
])
62 btrfs_set_lock_blocking_rw(p
->nodes
[i
], p
->locks
[i
]);
63 if (p
->locks
[i
] == BTRFS_READ_LOCK
)
64 p
->locks
[i
] = BTRFS_READ_LOCK_BLOCKING
;
65 else if (p
->locks
[i
] == BTRFS_WRITE_LOCK
)
66 p
->locks
[i
] = BTRFS_WRITE_LOCK_BLOCKING
;
71 * reset all the locked nodes in the patch to spinning locks.
73 * held is used to keep lockdep happy, when lockdep is enabled
74 * we set held to a blocking lock before we go around and
75 * retake all the spinlocks in the path. You can safely use NULL
78 noinline
void btrfs_clear_path_blocking(struct btrfs_path
*p
,
79 struct extent_buffer
*held
, int held_rw
)
83 #ifdef CONFIG_DEBUG_LOCK_ALLOC
84 /* lockdep really cares that we take all of these spinlocks
85 * in the right order. If any of the locks in the path are not
86 * currently blocking, it is going to complain. So, make really
87 * really sure by forcing the path to blocking before we clear
91 btrfs_set_lock_blocking_rw(held
, held_rw
);
92 if (held_rw
== BTRFS_WRITE_LOCK
)
93 held_rw
= BTRFS_WRITE_LOCK_BLOCKING
;
94 else if (held_rw
== BTRFS_READ_LOCK
)
95 held_rw
= BTRFS_READ_LOCK_BLOCKING
;
97 btrfs_set_path_blocking(p
);
100 for (i
= BTRFS_MAX_LEVEL
- 1; i
>= 0; i
--) {
101 if (p
->nodes
[i
] && p
->locks
[i
]) {
102 btrfs_clear_lock_blocking_rw(p
->nodes
[i
], p
->locks
[i
]);
103 if (p
->locks
[i
] == BTRFS_WRITE_LOCK_BLOCKING
)
104 p
->locks
[i
] = BTRFS_WRITE_LOCK
;
105 else if (p
->locks
[i
] == BTRFS_READ_LOCK_BLOCKING
)
106 p
->locks
[i
] = BTRFS_READ_LOCK
;
110 #ifdef CONFIG_DEBUG_LOCK_ALLOC
112 btrfs_clear_lock_blocking_rw(held
, held_rw
);
116 /* this also releases the path */
117 void btrfs_free_path(struct btrfs_path
*p
)
121 btrfs_release_path(p
);
122 kmem_cache_free(btrfs_path_cachep
, p
);
126 * path release drops references on the extent buffers in the path
127 * and it drops any locks held by this path
129 * It is safe to call this on paths that no locks or extent buffers held.
131 noinline
void btrfs_release_path(struct btrfs_path
*p
)
135 for (i
= 0; i
< BTRFS_MAX_LEVEL
; i
++) {
140 btrfs_tree_unlock_rw(p
->nodes
[i
], p
->locks
[i
]);
143 free_extent_buffer(p
->nodes
[i
]);
149 * safely gets a reference on the root node of a tree. A lock
150 * is not taken, so a concurrent writer may put a different node
151 * at the root of the tree. See btrfs_lock_root_node for the
154 * The extent buffer returned by this has a reference taken, so
155 * it won't disappear. It may stop being the root of the tree
156 * at any time because there are no locks held.
158 struct extent_buffer
*btrfs_root_node(struct btrfs_root
*root
)
160 struct extent_buffer
*eb
;
164 eb
= rcu_dereference(root
->node
);
167 * RCU really hurts here, we could free up the root node because
168 * it was cow'ed but we may not get the new root node yet so do
169 * the inc_not_zero dance and if it doesn't work then
170 * synchronize_rcu and try again.
172 if (atomic_inc_not_zero(&eb
->refs
)) {
182 /* loop around taking references on and locking the root node of the
183 * tree until you end up with a lock on the root. A locked buffer
184 * is returned, with a reference held.
186 struct extent_buffer
*btrfs_lock_root_node(struct btrfs_root
*root
)
188 struct extent_buffer
*eb
;
191 eb
= btrfs_root_node(root
);
193 if (eb
== root
->node
)
195 btrfs_tree_unlock(eb
);
196 free_extent_buffer(eb
);
201 /* loop around taking references on and locking the root node of the
202 * tree until you end up with a lock on the root. A locked buffer
203 * is returned, with a reference held.
205 static struct extent_buffer
*btrfs_read_lock_root_node(struct btrfs_root
*root
)
207 struct extent_buffer
*eb
;
210 eb
= btrfs_root_node(root
);
211 btrfs_tree_read_lock(eb
);
212 if (eb
== root
->node
)
214 btrfs_tree_read_unlock(eb
);
215 free_extent_buffer(eb
);
220 /* cowonly root (everything not a reference counted cow subvolume), just get
221 * put onto a simple dirty list. transaction.c walks this to make sure they
222 * get properly updated on disk.
224 static void add_root_to_dirty_list(struct btrfs_root
*root
)
226 spin_lock(&root
->fs_info
->trans_lock
);
227 if (test_bit(BTRFS_ROOT_TRACK_DIRTY
, &root
->state
) &&
228 list_empty(&root
->dirty_list
)) {
229 list_add(&root
->dirty_list
,
230 &root
->fs_info
->dirty_cowonly_roots
);
232 spin_unlock(&root
->fs_info
->trans_lock
);
236 * used by snapshot creation to make a copy of a root for a tree with
237 * a given objectid. The buffer with the new root node is returned in
238 * cow_ret, and this func returns zero on success or a negative error code.
240 int btrfs_copy_root(struct btrfs_trans_handle
*trans
,
241 struct btrfs_root
*root
,
242 struct extent_buffer
*buf
,
243 struct extent_buffer
**cow_ret
, u64 new_root_objectid
)
245 struct extent_buffer
*cow
;
248 struct btrfs_disk_key disk_key
;
250 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
251 trans
->transid
!= root
->fs_info
->running_transaction
->transid
);
252 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
253 trans
->transid
!= root
->last_trans
);
255 level
= btrfs_header_level(buf
);
257 btrfs_item_key(buf
, &disk_key
, 0);
259 btrfs_node_key(buf
, &disk_key
, 0);
261 cow
= btrfs_alloc_tree_block(trans
, root
, 0, new_root_objectid
,
262 &disk_key
, level
, buf
->start
, 0);
266 copy_extent_buffer(cow
, buf
, 0, 0, cow
->len
);
267 btrfs_set_header_bytenr(cow
, cow
->start
);
268 btrfs_set_header_generation(cow
, trans
->transid
);
269 btrfs_set_header_backref_rev(cow
, BTRFS_MIXED_BACKREF_REV
);
270 btrfs_clear_header_flag(cow
, BTRFS_HEADER_FLAG_WRITTEN
|
271 BTRFS_HEADER_FLAG_RELOC
);
272 if (new_root_objectid
== BTRFS_TREE_RELOC_OBJECTID
)
273 btrfs_set_header_flag(cow
, BTRFS_HEADER_FLAG_RELOC
);
275 btrfs_set_header_owner(cow
, new_root_objectid
);
277 write_extent_buffer(cow
, root
->fs_info
->fsid
, btrfs_header_fsid(),
280 WARN_ON(btrfs_header_generation(buf
) > trans
->transid
);
281 if (new_root_objectid
== BTRFS_TREE_RELOC_OBJECTID
)
282 ret
= btrfs_inc_ref(trans
, root
, cow
, 1);
284 ret
= btrfs_inc_ref(trans
, root
, cow
, 0);
289 btrfs_mark_buffer_dirty(cow
);
298 MOD_LOG_KEY_REMOVE_WHILE_FREEING
,
299 MOD_LOG_KEY_REMOVE_WHILE_MOVING
,
301 MOD_LOG_ROOT_REPLACE
,
304 struct tree_mod_move
{
309 struct tree_mod_root
{
314 struct tree_mod_elem
{
316 u64 index
; /* shifted logical */
320 /* this is used for MOD_LOG_KEY_* and MOD_LOG_MOVE_KEYS operations */
323 /* this is used for MOD_LOG_KEY* and MOD_LOG_ROOT_REPLACE */
326 /* those are used for op == MOD_LOG_KEY_{REPLACE,REMOVE} */
327 struct btrfs_disk_key key
;
330 /* this is used for op == MOD_LOG_MOVE_KEYS */
331 struct tree_mod_move move
;
333 /* this is used for op == MOD_LOG_ROOT_REPLACE */
334 struct tree_mod_root old_root
;
337 static inline void tree_mod_log_read_lock(struct btrfs_fs_info
*fs_info
)
339 read_lock(&fs_info
->tree_mod_log_lock
);
342 static inline void tree_mod_log_read_unlock(struct btrfs_fs_info
*fs_info
)
344 read_unlock(&fs_info
->tree_mod_log_lock
);
347 static inline void tree_mod_log_write_lock(struct btrfs_fs_info
*fs_info
)
349 write_lock(&fs_info
->tree_mod_log_lock
);
352 static inline void tree_mod_log_write_unlock(struct btrfs_fs_info
*fs_info
)
354 write_unlock(&fs_info
->tree_mod_log_lock
);
358 * Pull a new tree mod seq number for our operation.
360 static inline u64
btrfs_inc_tree_mod_seq(struct btrfs_fs_info
*fs_info
)
362 return atomic64_inc_return(&fs_info
->tree_mod_seq
);
366 * This adds a new blocker to the tree mod log's blocker list if the @elem
367 * passed does not already have a sequence number set. So when a caller expects
368 * to record tree modifications, it should ensure to set elem->seq to zero
369 * before calling btrfs_get_tree_mod_seq.
370 * Returns a fresh, unused tree log modification sequence number, even if no new
373 u64
btrfs_get_tree_mod_seq(struct btrfs_fs_info
*fs_info
,
374 struct seq_list
*elem
)
376 tree_mod_log_write_lock(fs_info
);
377 spin_lock(&fs_info
->tree_mod_seq_lock
);
379 elem
->seq
= btrfs_inc_tree_mod_seq(fs_info
);
380 list_add_tail(&elem
->list
, &fs_info
->tree_mod_seq_list
);
382 spin_unlock(&fs_info
->tree_mod_seq_lock
);
383 tree_mod_log_write_unlock(fs_info
);
388 void btrfs_put_tree_mod_seq(struct btrfs_fs_info
*fs_info
,
389 struct seq_list
*elem
)
391 struct rb_root
*tm_root
;
392 struct rb_node
*node
;
393 struct rb_node
*next
;
394 struct seq_list
*cur_elem
;
395 struct tree_mod_elem
*tm
;
396 u64 min_seq
= (u64
)-1;
397 u64 seq_putting
= elem
->seq
;
402 spin_lock(&fs_info
->tree_mod_seq_lock
);
403 list_del(&elem
->list
);
406 list_for_each_entry(cur_elem
, &fs_info
->tree_mod_seq_list
, list
) {
407 if (cur_elem
->seq
< min_seq
) {
408 if (seq_putting
> cur_elem
->seq
) {
410 * blocker with lower sequence number exists, we
411 * cannot remove anything from the log
413 spin_unlock(&fs_info
->tree_mod_seq_lock
);
416 min_seq
= cur_elem
->seq
;
419 spin_unlock(&fs_info
->tree_mod_seq_lock
);
422 * anything that's lower than the lowest existing (read: blocked)
423 * sequence number can be removed from the tree.
425 tree_mod_log_write_lock(fs_info
);
426 tm_root
= &fs_info
->tree_mod_log
;
427 for (node
= rb_first(tm_root
); node
; node
= next
) {
428 next
= rb_next(node
);
429 tm
= container_of(node
, struct tree_mod_elem
, node
);
430 if (tm
->seq
> min_seq
)
432 rb_erase(node
, tm_root
);
435 tree_mod_log_write_unlock(fs_info
);
439 * key order of the log:
442 * the index is the shifted logical of the *new* root node for root replace
443 * operations, or the shifted logical of the affected block for all other
446 * Note: must be called with write lock (tree_mod_log_write_lock).
449 __tree_mod_log_insert(struct btrfs_fs_info
*fs_info
, struct tree_mod_elem
*tm
)
451 struct rb_root
*tm_root
;
452 struct rb_node
**new;
453 struct rb_node
*parent
= NULL
;
454 struct tree_mod_elem
*cur
;
458 tm
->seq
= btrfs_inc_tree_mod_seq(fs_info
);
460 tm_root
= &fs_info
->tree_mod_log
;
461 new = &tm_root
->rb_node
;
463 cur
= container_of(*new, struct tree_mod_elem
, node
);
465 if (cur
->index
< tm
->index
)
466 new = &((*new)->rb_left
);
467 else if (cur
->index
> tm
->index
)
468 new = &((*new)->rb_right
);
469 else if (cur
->seq
< tm
->seq
)
470 new = &((*new)->rb_left
);
471 else if (cur
->seq
> tm
->seq
)
472 new = &((*new)->rb_right
);
477 rb_link_node(&tm
->node
, parent
, new);
478 rb_insert_color(&tm
->node
, tm_root
);
483 * Determines if logging can be omitted. Returns 1 if it can. Otherwise, it
484 * returns zero with the tree_mod_log_lock acquired. The caller must hold
485 * this until all tree mod log insertions are recorded in the rb tree and then
486 * call tree_mod_log_write_unlock() to release.
488 static inline int tree_mod_dont_log(struct btrfs_fs_info
*fs_info
,
489 struct extent_buffer
*eb
) {
491 if (list_empty(&(fs_info
)->tree_mod_seq_list
))
493 if (eb
&& btrfs_header_level(eb
) == 0)
496 tree_mod_log_write_lock(fs_info
);
497 if (list_empty(&(fs_info
)->tree_mod_seq_list
)) {
498 tree_mod_log_write_unlock(fs_info
);
505 /* Similar to tree_mod_dont_log, but doesn't acquire any locks. */
506 static inline int tree_mod_need_log(const struct btrfs_fs_info
*fs_info
,
507 struct extent_buffer
*eb
)
510 if (list_empty(&(fs_info
)->tree_mod_seq_list
))
512 if (eb
&& btrfs_header_level(eb
) == 0)
518 static struct tree_mod_elem
*
519 alloc_tree_mod_elem(struct extent_buffer
*eb
, int slot
,
520 enum mod_log_op op
, gfp_t flags
)
522 struct tree_mod_elem
*tm
;
524 tm
= kzalloc(sizeof(*tm
), flags
);
528 tm
->index
= eb
->start
>> PAGE_CACHE_SHIFT
;
529 if (op
!= MOD_LOG_KEY_ADD
) {
530 btrfs_node_key(eb
, &tm
->key
, slot
);
531 tm
->blockptr
= btrfs_node_blockptr(eb
, slot
);
535 tm
->generation
= btrfs_node_ptr_generation(eb
, slot
);
536 RB_CLEAR_NODE(&tm
->node
);
542 tree_mod_log_insert_key(struct btrfs_fs_info
*fs_info
,
543 struct extent_buffer
*eb
, int slot
,
544 enum mod_log_op op
, gfp_t flags
)
546 struct tree_mod_elem
*tm
;
549 if (!tree_mod_need_log(fs_info
, eb
))
552 tm
= alloc_tree_mod_elem(eb
, slot
, op
, flags
);
556 if (tree_mod_dont_log(fs_info
, eb
)) {
561 ret
= __tree_mod_log_insert(fs_info
, tm
);
562 tree_mod_log_write_unlock(fs_info
);
570 tree_mod_log_insert_move(struct btrfs_fs_info
*fs_info
,
571 struct extent_buffer
*eb
, int dst_slot
, int src_slot
,
572 int nr_items
, gfp_t flags
)
574 struct tree_mod_elem
*tm
= NULL
;
575 struct tree_mod_elem
**tm_list
= NULL
;
580 if (!tree_mod_need_log(fs_info
, eb
))
583 tm_list
= kzalloc(nr_items
* sizeof(struct tree_mod_elem
*), flags
);
587 tm
= kzalloc(sizeof(*tm
), flags
);
593 tm
->index
= eb
->start
>> PAGE_CACHE_SHIFT
;
595 tm
->move
.dst_slot
= dst_slot
;
596 tm
->move
.nr_items
= nr_items
;
597 tm
->op
= MOD_LOG_MOVE_KEYS
;
599 for (i
= 0; i
+ dst_slot
< src_slot
&& i
< nr_items
; i
++) {
600 tm_list
[i
] = alloc_tree_mod_elem(eb
, i
+ dst_slot
,
601 MOD_LOG_KEY_REMOVE_WHILE_MOVING
, flags
);
608 if (tree_mod_dont_log(fs_info
, eb
))
613 * When we override something during the move, we log these removals.
614 * This can only happen when we move towards the beginning of the
615 * buffer, i.e. dst_slot < src_slot.
617 for (i
= 0; i
+ dst_slot
< src_slot
&& i
< nr_items
; i
++) {
618 ret
= __tree_mod_log_insert(fs_info
, tm_list
[i
]);
623 ret
= __tree_mod_log_insert(fs_info
, tm
);
626 tree_mod_log_write_unlock(fs_info
);
631 for (i
= 0; i
< nr_items
; i
++) {
632 if (tm_list
[i
] && !RB_EMPTY_NODE(&tm_list
[i
]->node
))
633 rb_erase(&tm_list
[i
]->node
, &fs_info
->tree_mod_log
);
637 tree_mod_log_write_unlock(fs_info
);
645 __tree_mod_log_free_eb(struct btrfs_fs_info
*fs_info
,
646 struct tree_mod_elem
**tm_list
,
652 for (i
= nritems
- 1; i
>= 0; i
--) {
653 ret
= __tree_mod_log_insert(fs_info
, tm_list
[i
]);
655 for (j
= nritems
- 1; j
> i
; j
--)
656 rb_erase(&tm_list
[j
]->node
,
657 &fs_info
->tree_mod_log
);
666 tree_mod_log_insert_root(struct btrfs_fs_info
*fs_info
,
667 struct extent_buffer
*old_root
,
668 struct extent_buffer
*new_root
, gfp_t flags
,
671 struct tree_mod_elem
*tm
= NULL
;
672 struct tree_mod_elem
**tm_list
= NULL
;
677 if (!tree_mod_need_log(fs_info
, NULL
))
680 if (log_removal
&& btrfs_header_level(old_root
) > 0) {
681 nritems
= btrfs_header_nritems(old_root
);
682 tm_list
= kzalloc(nritems
* sizeof(struct tree_mod_elem
*),
688 for (i
= 0; i
< nritems
; i
++) {
689 tm_list
[i
] = alloc_tree_mod_elem(old_root
, i
,
690 MOD_LOG_KEY_REMOVE_WHILE_FREEING
, flags
);
698 tm
= kzalloc(sizeof(*tm
), flags
);
704 tm
->index
= new_root
->start
>> PAGE_CACHE_SHIFT
;
705 tm
->old_root
.logical
= old_root
->start
;
706 tm
->old_root
.level
= btrfs_header_level(old_root
);
707 tm
->generation
= btrfs_header_generation(old_root
);
708 tm
->op
= MOD_LOG_ROOT_REPLACE
;
710 if (tree_mod_dont_log(fs_info
, NULL
))
714 ret
= __tree_mod_log_free_eb(fs_info
, tm_list
, nritems
);
716 ret
= __tree_mod_log_insert(fs_info
, tm
);
718 tree_mod_log_write_unlock(fs_info
);
727 for (i
= 0; i
< nritems
; i
++)
736 static struct tree_mod_elem
*
737 __tree_mod_log_search(struct btrfs_fs_info
*fs_info
, u64 start
, u64 min_seq
,
740 struct rb_root
*tm_root
;
741 struct rb_node
*node
;
742 struct tree_mod_elem
*cur
= NULL
;
743 struct tree_mod_elem
*found
= NULL
;
744 u64 index
= start
>> PAGE_CACHE_SHIFT
;
746 tree_mod_log_read_lock(fs_info
);
747 tm_root
= &fs_info
->tree_mod_log
;
748 node
= tm_root
->rb_node
;
750 cur
= container_of(node
, struct tree_mod_elem
, node
);
751 if (cur
->index
< index
) {
752 node
= node
->rb_left
;
753 } else if (cur
->index
> index
) {
754 node
= node
->rb_right
;
755 } else if (cur
->seq
< min_seq
) {
756 node
= node
->rb_left
;
757 } else if (!smallest
) {
758 /* we want the node with the highest seq */
760 BUG_ON(found
->seq
> cur
->seq
);
762 node
= node
->rb_left
;
763 } else if (cur
->seq
> min_seq
) {
764 /* we want the node with the smallest seq */
766 BUG_ON(found
->seq
< cur
->seq
);
768 node
= node
->rb_right
;
774 tree_mod_log_read_unlock(fs_info
);
780 * this returns the element from the log with the smallest time sequence
781 * value that's in the log (the oldest log item). any element with a time
782 * sequence lower than min_seq will be ignored.
784 static struct tree_mod_elem
*
785 tree_mod_log_search_oldest(struct btrfs_fs_info
*fs_info
, u64 start
,
788 return __tree_mod_log_search(fs_info
, start
, min_seq
, 1);
792 * this returns the element from the log with the largest time sequence
793 * value that's in the log (the most recent log item). any element with
794 * a time sequence lower than min_seq will be ignored.
796 static struct tree_mod_elem
*
797 tree_mod_log_search(struct btrfs_fs_info
*fs_info
, u64 start
, u64 min_seq
)
799 return __tree_mod_log_search(fs_info
, start
, min_seq
, 0);
803 tree_mod_log_eb_copy(struct btrfs_fs_info
*fs_info
, struct extent_buffer
*dst
,
804 struct extent_buffer
*src
, unsigned long dst_offset
,
805 unsigned long src_offset
, int nr_items
)
808 struct tree_mod_elem
**tm_list
= NULL
;
809 struct tree_mod_elem
**tm_list_add
, **tm_list_rem
;
813 if (!tree_mod_need_log(fs_info
, NULL
))
816 if (btrfs_header_level(dst
) == 0 && btrfs_header_level(src
) == 0)
819 tm_list
= kzalloc(nr_items
* 2 * sizeof(struct tree_mod_elem
*),
824 tm_list_add
= tm_list
;
825 tm_list_rem
= tm_list
+ nr_items
;
826 for (i
= 0; i
< nr_items
; i
++) {
827 tm_list_rem
[i
] = alloc_tree_mod_elem(src
, i
+ src_offset
,
828 MOD_LOG_KEY_REMOVE
, GFP_NOFS
);
829 if (!tm_list_rem
[i
]) {
834 tm_list_add
[i
] = alloc_tree_mod_elem(dst
, i
+ dst_offset
,
835 MOD_LOG_KEY_ADD
, GFP_NOFS
);
836 if (!tm_list_add
[i
]) {
842 if (tree_mod_dont_log(fs_info
, NULL
))
846 for (i
= 0; i
< nr_items
; i
++) {
847 ret
= __tree_mod_log_insert(fs_info
, tm_list_rem
[i
]);
850 ret
= __tree_mod_log_insert(fs_info
, tm_list_add
[i
]);
855 tree_mod_log_write_unlock(fs_info
);
861 for (i
= 0; i
< nr_items
* 2; i
++) {
862 if (tm_list
[i
] && !RB_EMPTY_NODE(&tm_list
[i
]->node
))
863 rb_erase(&tm_list
[i
]->node
, &fs_info
->tree_mod_log
);
867 tree_mod_log_write_unlock(fs_info
);
874 tree_mod_log_eb_move(struct btrfs_fs_info
*fs_info
, struct extent_buffer
*dst
,
875 int dst_offset
, int src_offset
, int nr_items
)
878 ret
= tree_mod_log_insert_move(fs_info
, dst
, dst_offset
, src_offset
,
884 tree_mod_log_set_node_key(struct btrfs_fs_info
*fs_info
,
885 struct extent_buffer
*eb
, int slot
, int atomic
)
889 ret
= tree_mod_log_insert_key(fs_info
, eb
, slot
,
891 atomic
? GFP_ATOMIC
: GFP_NOFS
);
896 tree_mod_log_free_eb(struct btrfs_fs_info
*fs_info
, struct extent_buffer
*eb
)
898 struct tree_mod_elem
**tm_list
= NULL
;
903 if (btrfs_header_level(eb
) == 0)
906 if (!tree_mod_need_log(fs_info
, NULL
))
909 nritems
= btrfs_header_nritems(eb
);
910 tm_list
= kzalloc(nritems
* sizeof(struct tree_mod_elem
*),
915 for (i
= 0; i
< nritems
; i
++) {
916 tm_list
[i
] = alloc_tree_mod_elem(eb
, i
,
917 MOD_LOG_KEY_REMOVE_WHILE_FREEING
, GFP_NOFS
);
924 if (tree_mod_dont_log(fs_info
, eb
))
927 ret
= __tree_mod_log_free_eb(fs_info
, tm_list
, nritems
);
928 tree_mod_log_write_unlock(fs_info
);
936 for (i
= 0; i
< nritems
; i
++)
944 tree_mod_log_set_root_pointer(struct btrfs_root
*root
,
945 struct extent_buffer
*new_root_node
,
949 ret
= tree_mod_log_insert_root(root
->fs_info
, root
->node
,
950 new_root_node
, GFP_NOFS
, log_removal
);
955 * check if the tree block can be shared by multiple trees
957 int btrfs_block_can_be_shared(struct btrfs_root
*root
,
958 struct extent_buffer
*buf
)
961 * Tree blocks not in refernece counted trees and tree roots
962 * are never shared. If a block was allocated after the last
963 * snapshot and the block was not allocated by tree relocation,
964 * we know the block is not shared.
966 if (test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
967 buf
!= root
->node
&& buf
!= root
->commit_root
&&
968 (btrfs_header_generation(buf
) <=
969 btrfs_root_last_snapshot(&root
->root_item
) ||
970 btrfs_header_flag(buf
, BTRFS_HEADER_FLAG_RELOC
)))
972 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
973 if (test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
974 btrfs_header_backref_rev(buf
) < BTRFS_MIXED_BACKREF_REV
)
980 static noinline
int update_ref_for_cow(struct btrfs_trans_handle
*trans
,
981 struct btrfs_root
*root
,
982 struct extent_buffer
*buf
,
983 struct extent_buffer
*cow
,
993 * Backrefs update rules:
995 * Always use full backrefs for extent pointers in tree block
996 * allocated by tree relocation.
998 * If a shared tree block is no longer referenced by its owner
999 * tree (btrfs_header_owner(buf) == root->root_key.objectid),
1000 * use full backrefs for extent pointers in tree block.
1002 * If a tree block is been relocating
1003 * (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID),
1004 * use full backrefs for extent pointers in tree block.
1005 * The reason for this is some operations (such as drop tree)
1006 * are only allowed for blocks use full backrefs.
1009 if (btrfs_block_can_be_shared(root
, buf
)) {
1010 ret
= btrfs_lookup_extent_info(trans
, root
, buf
->start
,
1011 btrfs_header_level(buf
), 1,
1017 btrfs_std_error(root
->fs_info
, ret
);
1022 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
||
1023 btrfs_header_backref_rev(buf
) < BTRFS_MIXED_BACKREF_REV
)
1024 flags
= BTRFS_BLOCK_FLAG_FULL_BACKREF
;
1029 owner
= btrfs_header_owner(buf
);
1030 BUG_ON(owner
== BTRFS_TREE_RELOC_OBJECTID
&&
1031 !(flags
& BTRFS_BLOCK_FLAG_FULL_BACKREF
));
1034 if ((owner
== root
->root_key
.objectid
||
1035 root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
) &&
1036 !(flags
& BTRFS_BLOCK_FLAG_FULL_BACKREF
)) {
1037 ret
= btrfs_inc_ref(trans
, root
, buf
, 1);
1038 BUG_ON(ret
); /* -ENOMEM */
1040 if (root
->root_key
.objectid
==
1041 BTRFS_TREE_RELOC_OBJECTID
) {
1042 ret
= btrfs_dec_ref(trans
, root
, buf
, 0);
1043 BUG_ON(ret
); /* -ENOMEM */
1044 ret
= btrfs_inc_ref(trans
, root
, cow
, 1);
1045 BUG_ON(ret
); /* -ENOMEM */
1047 new_flags
|= BTRFS_BLOCK_FLAG_FULL_BACKREF
;
1050 if (root
->root_key
.objectid
==
1051 BTRFS_TREE_RELOC_OBJECTID
)
1052 ret
= btrfs_inc_ref(trans
, root
, cow
, 1);
1054 ret
= btrfs_inc_ref(trans
, root
, cow
, 0);
1055 BUG_ON(ret
); /* -ENOMEM */
1057 if (new_flags
!= 0) {
1058 int level
= btrfs_header_level(buf
);
1060 ret
= btrfs_set_disk_extent_flags(trans
, root
,
1063 new_flags
, level
, 0);
1068 if (flags
& BTRFS_BLOCK_FLAG_FULL_BACKREF
) {
1069 if (root
->root_key
.objectid
==
1070 BTRFS_TREE_RELOC_OBJECTID
)
1071 ret
= btrfs_inc_ref(trans
, root
, cow
, 1);
1073 ret
= btrfs_inc_ref(trans
, root
, cow
, 0);
1074 BUG_ON(ret
); /* -ENOMEM */
1075 ret
= btrfs_dec_ref(trans
, root
, buf
, 1);
1076 BUG_ON(ret
); /* -ENOMEM */
1078 clean_tree_block(trans
, root
, buf
);
1085 * does the dirty work in cow of a single block. The parent block (if
1086 * supplied) is updated to point to the new cow copy. The new buffer is marked
1087 * dirty and returned locked. If you modify the block it needs to be marked
1090 * search_start -- an allocation hint for the new block
1092 * empty_size -- a hint that you plan on doing more cow. This is the size in
1093 * bytes the allocator should try to find free next to the block it returns.
1094 * This is just a hint and may be ignored by the allocator.
1096 static noinline
int __btrfs_cow_block(struct btrfs_trans_handle
*trans
,
1097 struct btrfs_root
*root
,
1098 struct extent_buffer
*buf
,
1099 struct extent_buffer
*parent
, int parent_slot
,
1100 struct extent_buffer
**cow_ret
,
1101 u64 search_start
, u64 empty_size
)
1103 struct btrfs_disk_key disk_key
;
1104 struct extent_buffer
*cow
;
1107 int unlock_orig
= 0;
1110 if (*cow_ret
== buf
)
1113 btrfs_assert_tree_locked(buf
);
1115 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
1116 trans
->transid
!= root
->fs_info
->running_transaction
->transid
);
1117 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
1118 trans
->transid
!= root
->last_trans
);
1120 level
= btrfs_header_level(buf
);
1123 btrfs_item_key(buf
, &disk_key
, 0);
1125 btrfs_node_key(buf
, &disk_key
, 0);
1127 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
) {
1129 parent_start
= parent
->start
;
1135 cow
= btrfs_alloc_tree_block(trans
, root
, parent_start
,
1136 root
->root_key
.objectid
, &disk_key
, level
,
1137 search_start
, empty_size
);
1139 return PTR_ERR(cow
);
1141 /* cow is set to blocking by btrfs_init_new_buffer */
1143 copy_extent_buffer(cow
, buf
, 0, 0, cow
->len
);
1144 btrfs_set_header_bytenr(cow
, cow
->start
);
1145 btrfs_set_header_generation(cow
, trans
->transid
);
1146 btrfs_set_header_backref_rev(cow
, BTRFS_MIXED_BACKREF_REV
);
1147 btrfs_clear_header_flag(cow
, BTRFS_HEADER_FLAG_WRITTEN
|
1148 BTRFS_HEADER_FLAG_RELOC
);
1149 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
)
1150 btrfs_set_header_flag(cow
, BTRFS_HEADER_FLAG_RELOC
);
1152 btrfs_set_header_owner(cow
, root
->root_key
.objectid
);
1154 write_extent_buffer(cow
, root
->fs_info
->fsid
, btrfs_header_fsid(),
1157 ret
= update_ref_for_cow(trans
, root
, buf
, cow
, &last_ref
);
1159 btrfs_abort_transaction(trans
, root
, ret
);
1163 if (test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
)) {
1164 ret
= btrfs_reloc_cow_block(trans
, root
, buf
, cow
);
1169 if (buf
== root
->node
) {
1170 WARN_ON(parent
&& parent
!= buf
);
1171 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
||
1172 btrfs_header_backref_rev(buf
) < BTRFS_MIXED_BACKREF_REV
)
1173 parent_start
= buf
->start
;
1177 extent_buffer_get(cow
);
1178 tree_mod_log_set_root_pointer(root
, cow
, 1);
1179 rcu_assign_pointer(root
->node
, cow
);
1181 btrfs_free_tree_block(trans
, root
, buf
, parent_start
,
1183 free_extent_buffer(buf
);
1184 add_root_to_dirty_list(root
);
1186 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
)
1187 parent_start
= parent
->start
;
1191 WARN_ON(trans
->transid
!= btrfs_header_generation(parent
));
1192 tree_mod_log_insert_key(root
->fs_info
, parent
, parent_slot
,
1193 MOD_LOG_KEY_REPLACE
, GFP_NOFS
);
1194 btrfs_set_node_blockptr(parent
, parent_slot
,
1196 btrfs_set_node_ptr_generation(parent
, parent_slot
,
1198 btrfs_mark_buffer_dirty(parent
);
1200 ret
= tree_mod_log_free_eb(root
->fs_info
, buf
);
1202 btrfs_abort_transaction(trans
, root
, ret
);
1206 btrfs_free_tree_block(trans
, root
, buf
, parent_start
,
1210 btrfs_tree_unlock(buf
);
1211 free_extent_buffer_stale(buf
);
1212 btrfs_mark_buffer_dirty(cow
);
1218 * returns the logical address of the oldest predecessor of the given root.
1219 * entries older than time_seq are ignored.
1221 static struct tree_mod_elem
*
1222 __tree_mod_log_oldest_root(struct btrfs_fs_info
*fs_info
,
1223 struct extent_buffer
*eb_root
, u64 time_seq
)
1225 struct tree_mod_elem
*tm
;
1226 struct tree_mod_elem
*found
= NULL
;
1227 u64 root_logical
= eb_root
->start
;
1234 * the very last operation that's logged for a root is the replacement
1235 * operation (if it is replaced at all). this has the index of the *new*
1236 * root, making it the very first operation that's logged for this root.
1239 tm
= tree_mod_log_search_oldest(fs_info
, root_logical
,
1244 * if there are no tree operation for the oldest root, we simply
1245 * return it. this should only happen if that (old) root is at
1252 * if there's an operation that's not a root replacement, we
1253 * found the oldest version of our root. normally, we'll find a
1254 * MOD_LOG_KEY_REMOVE_WHILE_FREEING operation here.
1256 if (tm
->op
!= MOD_LOG_ROOT_REPLACE
)
1260 root_logical
= tm
->old_root
.logical
;
1264 /* if there's no old root to return, return what we found instead */
1272 * tm is a pointer to the first operation to rewind within eb. then, all
1273 * previous operations will be rewinded (until we reach something older than
1277 __tree_mod_log_rewind(struct btrfs_fs_info
*fs_info
, struct extent_buffer
*eb
,
1278 u64 time_seq
, struct tree_mod_elem
*first_tm
)
1281 struct rb_node
*next
;
1282 struct tree_mod_elem
*tm
= first_tm
;
1283 unsigned long o_dst
;
1284 unsigned long o_src
;
1285 unsigned long p_size
= sizeof(struct btrfs_key_ptr
);
1287 n
= btrfs_header_nritems(eb
);
1288 tree_mod_log_read_lock(fs_info
);
1289 while (tm
&& tm
->seq
>= time_seq
) {
1291 * all the operations are recorded with the operator used for
1292 * the modification. as we're going backwards, we do the
1293 * opposite of each operation here.
1296 case MOD_LOG_KEY_REMOVE_WHILE_FREEING
:
1297 BUG_ON(tm
->slot
< n
);
1299 case MOD_LOG_KEY_REMOVE_WHILE_MOVING
:
1300 case MOD_LOG_KEY_REMOVE
:
1301 btrfs_set_node_key(eb
, &tm
->key
, tm
->slot
);
1302 btrfs_set_node_blockptr(eb
, tm
->slot
, tm
->blockptr
);
1303 btrfs_set_node_ptr_generation(eb
, tm
->slot
,
1307 case MOD_LOG_KEY_REPLACE
:
1308 BUG_ON(tm
->slot
>= n
);
1309 btrfs_set_node_key(eb
, &tm
->key
, tm
->slot
);
1310 btrfs_set_node_blockptr(eb
, tm
->slot
, tm
->blockptr
);
1311 btrfs_set_node_ptr_generation(eb
, tm
->slot
,
1314 case MOD_LOG_KEY_ADD
:
1315 /* if a move operation is needed it's in the log */
1318 case MOD_LOG_MOVE_KEYS
:
1319 o_dst
= btrfs_node_key_ptr_offset(tm
->slot
);
1320 o_src
= btrfs_node_key_ptr_offset(tm
->move
.dst_slot
);
1321 memmove_extent_buffer(eb
, o_dst
, o_src
,
1322 tm
->move
.nr_items
* p_size
);
1324 case MOD_LOG_ROOT_REPLACE
:
1326 * this operation is special. for roots, this must be
1327 * handled explicitly before rewinding.
1328 * for non-roots, this operation may exist if the node
1329 * was a root: root A -> child B; then A gets empty and
1330 * B is promoted to the new root. in the mod log, we'll
1331 * have a root-replace operation for B, a tree block
1332 * that is no root. we simply ignore that operation.
1336 next
= rb_next(&tm
->node
);
1339 tm
= container_of(next
, struct tree_mod_elem
, node
);
1340 if (tm
->index
!= first_tm
->index
)
1343 tree_mod_log_read_unlock(fs_info
);
1344 btrfs_set_header_nritems(eb
, n
);
1348 * Called with eb read locked. If the buffer cannot be rewinded, the same buffer
1349 * is returned. If rewind operations happen, a fresh buffer is returned. The
1350 * returned buffer is always read-locked. If the returned buffer is not the
1351 * input buffer, the lock on the input buffer is released and the input buffer
1352 * is freed (its refcount is decremented).
1354 static struct extent_buffer
*
1355 tree_mod_log_rewind(struct btrfs_fs_info
*fs_info
, struct btrfs_path
*path
,
1356 struct extent_buffer
*eb
, u64 time_seq
)
1358 struct extent_buffer
*eb_rewin
;
1359 struct tree_mod_elem
*tm
;
1364 if (btrfs_header_level(eb
) == 0)
1367 tm
= tree_mod_log_search(fs_info
, eb
->start
, time_seq
);
1371 btrfs_set_path_blocking(path
);
1372 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1374 if (tm
->op
== MOD_LOG_KEY_REMOVE_WHILE_FREEING
) {
1375 BUG_ON(tm
->slot
!= 0);
1376 eb_rewin
= alloc_dummy_extent_buffer(eb
->start
,
1377 fs_info
->tree_root
->nodesize
);
1379 btrfs_tree_read_unlock_blocking(eb
);
1380 free_extent_buffer(eb
);
1383 btrfs_set_header_bytenr(eb_rewin
, eb
->start
);
1384 btrfs_set_header_backref_rev(eb_rewin
,
1385 btrfs_header_backref_rev(eb
));
1386 btrfs_set_header_owner(eb_rewin
, btrfs_header_owner(eb
));
1387 btrfs_set_header_level(eb_rewin
, btrfs_header_level(eb
));
1389 eb_rewin
= btrfs_clone_extent_buffer(eb
);
1391 btrfs_tree_read_unlock_blocking(eb
);
1392 free_extent_buffer(eb
);
1397 btrfs_clear_path_blocking(path
, NULL
, BTRFS_READ_LOCK
);
1398 btrfs_tree_read_unlock_blocking(eb
);
1399 free_extent_buffer(eb
);
1401 extent_buffer_get(eb_rewin
);
1402 btrfs_tree_read_lock(eb_rewin
);
1403 __tree_mod_log_rewind(fs_info
, eb_rewin
, time_seq
, tm
);
1404 WARN_ON(btrfs_header_nritems(eb_rewin
) >
1405 BTRFS_NODEPTRS_PER_BLOCK(fs_info
->tree_root
));
1411 * get_old_root() rewinds the state of @root's root node to the given @time_seq
1412 * value. If there are no changes, the current root->root_node is returned. If
1413 * anything changed in between, there's a fresh buffer allocated on which the
1414 * rewind operations are done. In any case, the returned buffer is read locked.
1415 * Returns NULL on error (with no locks held).
1417 static inline struct extent_buffer
*
1418 get_old_root(struct btrfs_root
*root
, u64 time_seq
)
1420 struct tree_mod_elem
*tm
;
1421 struct extent_buffer
*eb
= NULL
;
1422 struct extent_buffer
*eb_root
;
1423 struct extent_buffer
*old
;
1424 struct tree_mod_root
*old_root
= NULL
;
1425 u64 old_generation
= 0;
1428 eb_root
= btrfs_read_lock_root_node(root
);
1429 tm
= __tree_mod_log_oldest_root(root
->fs_info
, eb_root
, time_seq
);
1433 if (tm
->op
== MOD_LOG_ROOT_REPLACE
) {
1434 old_root
= &tm
->old_root
;
1435 old_generation
= tm
->generation
;
1436 logical
= old_root
->logical
;
1438 logical
= eb_root
->start
;
1441 tm
= tree_mod_log_search(root
->fs_info
, logical
, time_seq
);
1442 if (old_root
&& tm
&& tm
->op
!= MOD_LOG_KEY_REMOVE_WHILE_FREEING
) {
1443 btrfs_tree_read_unlock(eb_root
);
1444 free_extent_buffer(eb_root
);
1445 old
= read_tree_block(root
, logical
, 0);
1446 if (WARN_ON(!old
|| !extent_buffer_uptodate(old
))) {
1447 free_extent_buffer(old
);
1448 btrfs_warn(root
->fs_info
,
1449 "failed to read tree block %llu from get_old_root", logical
);
1451 eb
= btrfs_clone_extent_buffer(old
);
1452 free_extent_buffer(old
);
1454 } else if (old_root
) {
1455 btrfs_tree_read_unlock(eb_root
);
1456 free_extent_buffer(eb_root
);
1457 eb
= alloc_dummy_extent_buffer(logical
, root
->nodesize
);
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_test_is_dummy_root(root
))
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 commiting 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 cow'd 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
)) {
1559 search_start
= buf
->start
& ~((u64
)(1024 * 1024 * 1024) - 1);
1562 btrfs_set_lock_blocking(parent
);
1563 btrfs_set_lock_blocking(buf
);
1565 ret
= __btrfs_cow_block(trans
, root
, buf
, parent
,
1566 parent_slot
, cow_ret
, search_start
, 0);
1568 trace_btrfs_cow_block(root
, buf
, *cow_ret
);
1574 * helper function for defrag to decide if two blocks pointed to by a
1575 * node are actually close by
1577 static int close_blocks(u64 blocknr
, u64 other
, u32 blocksize
)
1579 if (blocknr
< other
&& other
- (blocknr
+ blocksize
) < 32768)
1581 if (blocknr
> other
&& blocknr
- (other
+ blocksize
) < 32768)
1587 * compare two keys in a memcmp fashion
1589 static int comp_keys(struct btrfs_disk_key
*disk
, struct btrfs_key
*k2
)
1591 struct btrfs_key k1
;
1593 btrfs_disk_key_to_cpu(&k1
, disk
);
1595 return btrfs_comp_cpu_keys(&k1
, k2
);
1599 * same as comp_keys only with two btrfs_key's
1601 int btrfs_comp_cpu_keys(struct btrfs_key
*k1
, struct btrfs_key
*k2
)
1603 if (k1
->objectid
> k2
->objectid
)
1605 if (k1
->objectid
< k2
->objectid
)
1607 if (k1
->type
> k2
->type
)
1609 if (k1
->type
< k2
->type
)
1611 if (k1
->offset
> k2
->offset
)
1613 if (k1
->offset
< k2
->offset
)
1619 * this is used by the defrag code to go through all the
1620 * leaves pointed to by a node and reallocate them so that
1621 * disk order is close to key order
1623 int btrfs_realloc_node(struct btrfs_trans_handle
*trans
,
1624 struct btrfs_root
*root
, struct extent_buffer
*parent
,
1625 int start_slot
, u64
*last_ret
,
1626 struct btrfs_key
*progress
)
1628 struct extent_buffer
*cur
;
1631 u64 search_start
= *last_ret
;
1641 int progress_passed
= 0;
1642 struct btrfs_disk_key disk_key
;
1644 parent_level
= btrfs_header_level(parent
);
1646 WARN_ON(trans
->transaction
!= root
->fs_info
->running_transaction
);
1647 WARN_ON(trans
->transid
!= root
->fs_info
->generation
);
1649 parent_nritems
= btrfs_header_nritems(parent
);
1650 blocksize
= root
->nodesize
;
1651 end_slot
= parent_nritems
;
1653 if (parent_nritems
== 1)
1656 btrfs_set_lock_blocking(parent
);
1658 for (i
= start_slot
; i
< end_slot
; i
++) {
1661 btrfs_node_key(parent
, &disk_key
, i
);
1662 if (!progress_passed
&& comp_keys(&disk_key
, progress
) < 0)
1665 progress_passed
= 1;
1666 blocknr
= btrfs_node_blockptr(parent
, i
);
1667 gen
= btrfs_node_ptr_generation(parent
, i
);
1668 if (last_block
== 0)
1669 last_block
= blocknr
;
1672 other
= btrfs_node_blockptr(parent
, i
- 1);
1673 close
= close_blocks(blocknr
, other
, blocksize
);
1675 if (!close
&& i
< end_slot
- 2) {
1676 other
= btrfs_node_blockptr(parent
, i
+ 1);
1677 close
= close_blocks(blocknr
, other
, blocksize
);
1680 last_block
= blocknr
;
1684 cur
= btrfs_find_tree_block(root
, blocknr
);
1686 uptodate
= btrfs_buffer_uptodate(cur
, gen
, 0);
1689 if (!cur
|| !uptodate
) {
1691 cur
= read_tree_block(root
, blocknr
, gen
);
1692 if (!cur
|| !extent_buffer_uptodate(cur
)) {
1693 free_extent_buffer(cur
);
1696 } else if (!uptodate
) {
1697 err
= btrfs_read_buffer(cur
, gen
);
1699 free_extent_buffer(cur
);
1704 if (search_start
== 0)
1705 search_start
= last_block
;
1707 btrfs_tree_lock(cur
);
1708 btrfs_set_lock_blocking(cur
);
1709 err
= __btrfs_cow_block(trans
, root
, cur
, parent
, i
,
1712 (end_slot
- i
) * blocksize
));
1714 btrfs_tree_unlock(cur
);
1715 free_extent_buffer(cur
);
1718 search_start
= cur
->start
;
1719 last_block
= cur
->start
;
1720 *last_ret
= search_start
;
1721 btrfs_tree_unlock(cur
);
1722 free_extent_buffer(cur
);
1728 * The leaf data grows from end-to-front in the node.
1729 * this returns the address of the start of the last item,
1730 * which is the stop of the leaf data stack
1732 static inline unsigned int leaf_data_end(struct btrfs_root
*root
,
1733 struct extent_buffer
*leaf
)
1735 u32 nr
= btrfs_header_nritems(leaf
);
1737 return BTRFS_LEAF_DATA_SIZE(root
);
1738 return btrfs_item_offset_nr(leaf
, nr
- 1);
1743 * search for key in the extent_buffer. The items start at offset p,
1744 * and they are item_size apart. There are 'max' items in p.
1746 * the slot in the array is returned via slot, and it points to
1747 * the place where you would insert key if it is not found in
1750 * slot may point to max if the key is bigger than all of the keys
1752 static noinline
int generic_bin_search(struct extent_buffer
*eb
,
1754 int item_size
, struct btrfs_key
*key
,
1761 struct btrfs_disk_key
*tmp
= NULL
;
1762 struct btrfs_disk_key unaligned
;
1763 unsigned long offset
;
1765 unsigned long map_start
= 0;
1766 unsigned long map_len
= 0;
1769 while (low
< high
) {
1770 mid
= (low
+ high
) / 2;
1771 offset
= p
+ mid
* item_size
;
1773 if (!kaddr
|| offset
< map_start
||
1774 (offset
+ sizeof(struct btrfs_disk_key
)) >
1775 map_start
+ map_len
) {
1777 err
= map_private_extent_buffer(eb
, offset
,
1778 sizeof(struct btrfs_disk_key
),
1779 &kaddr
, &map_start
, &map_len
);
1782 tmp
= (struct btrfs_disk_key
*)(kaddr
+ offset
-
1785 read_extent_buffer(eb
, &unaligned
,
1786 offset
, sizeof(unaligned
));
1791 tmp
= (struct btrfs_disk_key
*)(kaddr
+ offset
-
1794 ret
= comp_keys(tmp
, key
);
1810 * simple bin_search frontend that does the right thing for
1813 static int bin_search(struct extent_buffer
*eb
, struct btrfs_key
*key
,
1814 int level
, int *slot
)
1817 return generic_bin_search(eb
,
1818 offsetof(struct btrfs_leaf
, items
),
1819 sizeof(struct btrfs_item
),
1820 key
, btrfs_header_nritems(eb
),
1823 return generic_bin_search(eb
,
1824 offsetof(struct btrfs_node
, ptrs
),
1825 sizeof(struct btrfs_key_ptr
),
1826 key
, btrfs_header_nritems(eb
),
1830 int btrfs_bin_search(struct extent_buffer
*eb
, struct btrfs_key
*key
,
1831 int level
, int *slot
)
1833 return bin_search(eb
, key
, level
, slot
);
1836 static void root_add_used(struct btrfs_root
*root
, u32 size
)
1838 spin_lock(&root
->accounting_lock
);
1839 btrfs_set_root_used(&root
->root_item
,
1840 btrfs_root_used(&root
->root_item
) + size
);
1841 spin_unlock(&root
->accounting_lock
);
1844 static void root_sub_used(struct btrfs_root
*root
, u32 size
)
1846 spin_lock(&root
->accounting_lock
);
1847 btrfs_set_root_used(&root
->root_item
,
1848 btrfs_root_used(&root
->root_item
) - size
);
1849 spin_unlock(&root
->accounting_lock
);
1852 /* given a node and slot number, this reads the blocks it points to. The
1853 * extent buffer is returned with a reference taken (but unlocked).
1854 * NULL is returned on error.
1856 static noinline
struct extent_buffer
*read_node_slot(struct btrfs_root
*root
,
1857 struct extent_buffer
*parent
, int slot
)
1859 int level
= btrfs_header_level(parent
);
1860 struct extent_buffer
*eb
;
1864 if (slot
>= btrfs_header_nritems(parent
))
1869 eb
= read_tree_block(root
, btrfs_node_blockptr(parent
, slot
),
1870 btrfs_node_ptr_generation(parent
, slot
));
1871 if (eb
&& !extent_buffer_uptodate(eb
)) {
1872 free_extent_buffer(eb
);
1880 * node level balancing, used to make sure nodes are in proper order for
1881 * item deletion. We balance from the top down, so we have to make sure
1882 * that a deletion won't leave an node completely empty later on.
1884 static noinline
int balance_level(struct btrfs_trans_handle
*trans
,
1885 struct btrfs_root
*root
,
1886 struct btrfs_path
*path
, int level
)
1888 struct extent_buffer
*right
= NULL
;
1889 struct extent_buffer
*mid
;
1890 struct extent_buffer
*left
= NULL
;
1891 struct extent_buffer
*parent
= NULL
;
1895 int orig_slot
= path
->slots
[level
];
1901 mid
= path
->nodes
[level
];
1903 WARN_ON(path
->locks
[level
] != BTRFS_WRITE_LOCK
&&
1904 path
->locks
[level
] != BTRFS_WRITE_LOCK_BLOCKING
);
1905 WARN_ON(btrfs_header_generation(mid
) != trans
->transid
);
1907 orig_ptr
= btrfs_node_blockptr(mid
, orig_slot
);
1909 if (level
< BTRFS_MAX_LEVEL
- 1) {
1910 parent
= path
->nodes
[level
+ 1];
1911 pslot
= path
->slots
[level
+ 1];
1915 * deal with the case where there is only one pointer in the root
1916 * by promoting the node below to a root
1919 struct extent_buffer
*child
;
1921 if (btrfs_header_nritems(mid
) != 1)
1924 /* promote the child to a root */
1925 child
= read_node_slot(root
, mid
, 0);
1928 btrfs_std_error(root
->fs_info
, ret
);
1932 btrfs_tree_lock(child
);
1933 btrfs_set_lock_blocking(child
);
1934 ret
= btrfs_cow_block(trans
, root
, child
, mid
, 0, &child
);
1936 btrfs_tree_unlock(child
);
1937 free_extent_buffer(child
);
1941 tree_mod_log_set_root_pointer(root
, child
, 1);
1942 rcu_assign_pointer(root
->node
, child
);
1944 add_root_to_dirty_list(root
);
1945 btrfs_tree_unlock(child
);
1947 path
->locks
[level
] = 0;
1948 path
->nodes
[level
] = NULL
;
1949 clean_tree_block(trans
, root
, mid
);
1950 btrfs_tree_unlock(mid
);
1951 /* once for the path */
1952 free_extent_buffer(mid
);
1954 root_sub_used(root
, mid
->len
);
1955 btrfs_free_tree_block(trans
, root
, mid
, 0, 1);
1956 /* once for the root ptr */
1957 free_extent_buffer_stale(mid
);
1960 if (btrfs_header_nritems(mid
) >
1961 BTRFS_NODEPTRS_PER_BLOCK(root
) / 4)
1964 left
= read_node_slot(root
, parent
, pslot
- 1);
1966 btrfs_tree_lock(left
);
1967 btrfs_set_lock_blocking(left
);
1968 wret
= btrfs_cow_block(trans
, root
, left
,
1969 parent
, pslot
- 1, &left
);
1975 right
= read_node_slot(root
, parent
, pslot
+ 1);
1977 btrfs_tree_lock(right
);
1978 btrfs_set_lock_blocking(right
);
1979 wret
= btrfs_cow_block(trans
, root
, right
,
1980 parent
, pslot
+ 1, &right
);
1987 /* first, try to make some room in the middle buffer */
1989 orig_slot
+= btrfs_header_nritems(left
);
1990 wret
= push_node_left(trans
, root
, left
, mid
, 1);
1996 * then try to empty the right most buffer into the middle
1999 wret
= push_node_left(trans
, root
, mid
, right
, 1);
2000 if (wret
< 0 && wret
!= -ENOSPC
)
2002 if (btrfs_header_nritems(right
) == 0) {
2003 clean_tree_block(trans
, root
, right
);
2004 btrfs_tree_unlock(right
);
2005 del_ptr(root
, path
, level
+ 1, pslot
+ 1);
2006 root_sub_used(root
, right
->len
);
2007 btrfs_free_tree_block(trans
, root
, right
, 0, 1);
2008 free_extent_buffer_stale(right
);
2011 struct btrfs_disk_key right_key
;
2012 btrfs_node_key(right
, &right_key
, 0);
2013 tree_mod_log_set_node_key(root
->fs_info
, parent
,
2015 btrfs_set_node_key(parent
, &right_key
, pslot
+ 1);
2016 btrfs_mark_buffer_dirty(parent
);
2019 if (btrfs_header_nritems(mid
) == 1) {
2021 * we're not allowed to leave a node with one item in the
2022 * tree during a delete. A deletion from lower in the tree
2023 * could try to delete the only pointer in this node.
2024 * So, pull some keys from the left.
2025 * There has to be a left pointer at this point because
2026 * otherwise we would have pulled some pointers from the
2031 btrfs_std_error(root
->fs_info
, ret
);
2034 wret
= balance_node_right(trans
, root
, mid
, left
);
2040 wret
= push_node_left(trans
, root
, left
, mid
, 1);
2046 if (btrfs_header_nritems(mid
) == 0) {
2047 clean_tree_block(trans
, root
, mid
);
2048 btrfs_tree_unlock(mid
);
2049 del_ptr(root
, path
, level
+ 1, pslot
);
2050 root_sub_used(root
, mid
->len
);
2051 btrfs_free_tree_block(trans
, root
, mid
, 0, 1);
2052 free_extent_buffer_stale(mid
);
2055 /* update the parent key to reflect our changes */
2056 struct btrfs_disk_key mid_key
;
2057 btrfs_node_key(mid
, &mid_key
, 0);
2058 tree_mod_log_set_node_key(root
->fs_info
, parent
,
2060 btrfs_set_node_key(parent
, &mid_key
, pslot
);
2061 btrfs_mark_buffer_dirty(parent
);
2064 /* update the path */
2066 if (btrfs_header_nritems(left
) > orig_slot
) {
2067 extent_buffer_get(left
);
2068 /* left was locked after cow */
2069 path
->nodes
[level
] = left
;
2070 path
->slots
[level
+ 1] -= 1;
2071 path
->slots
[level
] = orig_slot
;
2073 btrfs_tree_unlock(mid
);
2074 free_extent_buffer(mid
);
2077 orig_slot
-= btrfs_header_nritems(left
);
2078 path
->slots
[level
] = orig_slot
;
2081 /* double check we haven't messed things up */
2083 btrfs_node_blockptr(path
->nodes
[level
], path
->slots
[level
]))
2087 btrfs_tree_unlock(right
);
2088 free_extent_buffer(right
);
2091 if (path
->nodes
[level
] != left
)
2092 btrfs_tree_unlock(left
);
2093 free_extent_buffer(left
);
2098 /* Node balancing for insertion. Here we only split or push nodes around
2099 * when they are completely full. This is also done top down, so we
2100 * have to be pessimistic.
2102 static noinline
int push_nodes_for_insert(struct btrfs_trans_handle
*trans
,
2103 struct btrfs_root
*root
,
2104 struct btrfs_path
*path
, int level
)
2106 struct extent_buffer
*right
= NULL
;
2107 struct extent_buffer
*mid
;
2108 struct extent_buffer
*left
= NULL
;
2109 struct extent_buffer
*parent
= NULL
;
2113 int orig_slot
= path
->slots
[level
];
2118 mid
= path
->nodes
[level
];
2119 WARN_ON(btrfs_header_generation(mid
) != trans
->transid
);
2121 if (level
< BTRFS_MAX_LEVEL
- 1) {
2122 parent
= path
->nodes
[level
+ 1];
2123 pslot
= path
->slots
[level
+ 1];
2129 left
= read_node_slot(root
, parent
, pslot
- 1);
2131 /* first, try to make some room in the middle buffer */
2135 btrfs_tree_lock(left
);
2136 btrfs_set_lock_blocking(left
);
2138 left_nr
= btrfs_header_nritems(left
);
2139 if (left_nr
>= BTRFS_NODEPTRS_PER_BLOCK(root
) - 1) {
2142 ret
= btrfs_cow_block(trans
, root
, left
, parent
,
2147 wret
= push_node_left(trans
, root
,
2154 struct btrfs_disk_key disk_key
;
2155 orig_slot
+= left_nr
;
2156 btrfs_node_key(mid
, &disk_key
, 0);
2157 tree_mod_log_set_node_key(root
->fs_info
, parent
,
2159 btrfs_set_node_key(parent
, &disk_key
, pslot
);
2160 btrfs_mark_buffer_dirty(parent
);
2161 if (btrfs_header_nritems(left
) > orig_slot
) {
2162 path
->nodes
[level
] = left
;
2163 path
->slots
[level
+ 1] -= 1;
2164 path
->slots
[level
] = orig_slot
;
2165 btrfs_tree_unlock(mid
);
2166 free_extent_buffer(mid
);
2169 btrfs_header_nritems(left
);
2170 path
->slots
[level
] = orig_slot
;
2171 btrfs_tree_unlock(left
);
2172 free_extent_buffer(left
);
2176 btrfs_tree_unlock(left
);
2177 free_extent_buffer(left
);
2179 right
= read_node_slot(root
, parent
, pslot
+ 1);
2182 * then try to empty the right most buffer into the middle
2187 btrfs_tree_lock(right
);
2188 btrfs_set_lock_blocking(right
);
2190 right_nr
= btrfs_header_nritems(right
);
2191 if (right_nr
>= BTRFS_NODEPTRS_PER_BLOCK(root
) - 1) {
2194 ret
= btrfs_cow_block(trans
, root
, right
,
2200 wret
= balance_node_right(trans
, root
,
2207 struct btrfs_disk_key disk_key
;
2209 btrfs_node_key(right
, &disk_key
, 0);
2210 tree_mod_log_set_node_key(root
->fs_info
, parent
,
2212 btrfs_set_node_key(parent
, &disk_key
, pslot
+ 1);
2213 btrfs_mark_buffer_dirty(parent
);
2215 if (btrfs_header_nritems(mid
) <= orig_slot
) {
2216 path
->nodes
[level
] = right
;
2217 path
->slots
[level
+ 1] += 1;
2218 path
->slots
[level
] = orig_slot
-
2219 btrfs_header_nritems(mid
);
2220 btrfs_tree_unlock(mid
);
2221 free_extent_buffer(mid
);
2223 btrfs_tree_unlock(right
);
2224 free_extent_buffer(right
);
2228 btrfs_tree_unlock(right
);
2229 free_extent_buffer(right
);
2235 * readahead one full node of leaves, finding things that are close
2236 * to the block in 'slot', and triggering ra on them.
2238 static void reada_for_search(struct btrfs_root
*root
,
2239 struct btrfs_path
*path
,
2240 int level
, int slot
, u64 objectid
)
2242 struct extent_buffer
*node
;
2243 struct btrfs_disk_key disk_key
;
2249 int direction
= path
->reada
;
2250 struct extent_buffer
*eb
;
2258 if (!path
->nodes
[level
])
2261 node
= path
->nodes
[level
];
2263 search
= btrfs_node_blockptr(node
, slot
);
2264 blocksize
= root
->nodesize
;
2265 eb
= btrfs_find_tree_block(root
, search
);
2267 free_extent_buffer(eb
);
2273 nritems
= btrfs_header_nritems(node
);
2277 if (direction
< 0) {
2281 } else if (direction
> 0) {
2286 if (path
->reada
< 0 && objectid
) {
2287 btrfs_node_key(node
, &disk_key
, nr
);
2288 if (btrfs_disk_key_objectid(&disk_key
) != objectid
)
2291 search
= btrfs_node_blockptr(node
, nr
);
2292 if ((search
<= target
&& target
- search
<= 65536) ||
2293 (search
> target
&& search
- target
<= 65536)) {
2294 gen
= btrfs_node_ptr_generation(node
, nr
);
2295 readahead_tree_block(root
, search
, blocksize
);
2299 if ((nread
> 65536 || nscan
> 32))
2304 static noinline
void reada_for_balance(struct btrfs_root
*root
,
2305 struct btrfs_path
*path
, int level
)
2309 struct extent_buffer
*parent
;
2310 struct extent_buffer
*eb
;
2316 parent
= path
->nodes
[level
+ 1];
2320 nritems
= btrfs_header_nritems(parent
);
2321 slot
= path
->slots
[level
+ 1];
2322 blocksize
= root
->nodesize
;
2325 block1
= btrfs_node_blockptr(parent
, slot
- 1);
2326 gen
= btrfs_node_ptr_generation(parent
, slot
- 1);
2327 eb
= btrfs_find_tree_block(root
, block1
);
2329 * if we get -eagain from btrfs_buffer_uptodate, we
2330 * don't want to return eagain here. That will loop
2333 if (eb
&& btrfs_buffer_uptodate(eb
, gen
, 1) != 0)
2335 free_extent_buffer(eb
);
2337 if (slot
+ 1 < nritems
) {
2338 block2
= btrfs_node_blockptr(parent
, slot
+ 1);
2339 gen
= btrfs_node_ptr_generation(parent
, slot
+ 1);
2340 eb
= btrfs_find_tree_block(root
, block2
);
2341 if (eb
&& btrfs_buffer_uptodate(eb
, gen
, 1) != 0)
2343 free_extent_buffer(eb
);
2347 readahead_tree_block(root
, block1
, blocksize
);
2349 readahead_tree_block(root
, block2
, blocksize
);
2354 * when we walk down the tree, it is usually safe to unlock the higher layers
2355 * in the tree. The exceptions are when our path goes through slot 0, because
2356 * operations on the tree might require changing key pointers higher up in the
2359 * callers might also have set path->keep_locks, which tells this code to keep
2360 * the lock if the path points to the last slot in the block. This is part of
2361 * walking through the tree, and selecting the next slot in the higher block.
2363 * lowest_unlock sets the lowest level in the tree we're allowed to unlock. so
2364 * if lowest_unlock is 1, level 0 won't be unlocked
2366 static noinline
void unlock_up(struct btrfs_path
*path
, int level
,
2367 int lowest_unlock
, int min_write_lock_level
,
2368 int *write_lock_level
)
2371 int skip_level
= level
;
2373 struct extent_buffer
*t
;
2375 for (i
= level
; i
< BTRFS_MAX_LEVEL
; i
++) {
2376 if (!path
->nodes
[i
])
2378 if (!path
->locks
[i
])
2380 if (!no_skips
&& path
->slots
[i
] == 0) {
2384 if (!no_skips
&& path
->keep_locks
) {
2387 nritems
= btrfs_header_nritems(t
);
2388 if (nritems
< 1 || path
->slots
[i
] >= nritems
- 1) {
2393 if (skip_level
< i
&& i
>= lowest_unlock
)
2397 if (i
>= lowest_unlock
&& i
> skip_level
&& path
->locks
[i
]) {
2398 btrfs_tree_unlock_rw(t
, path
->locks
[i
]);
2400 if (write_lock_level
&&
2401 i
> min_write_lock_level
&&
2402 i
<= *write_lock_level
) {
2403 *write_lock_level
= i
- 1;
2410 * This releases any locks held in the path starting at level and
2411 * going all the way up to the root.
2413 * btrfs_search_slot will keep the lock held on higher nodes in a few
2414 * corner cases, such as COW of the block at slot zero in the node. This
2415 * ignores those rules, and it should only be called when there are no
2416 * more updates to be done higher up in the tree.
2418 noinline
void btrfs_unlock_up_safe(struct btrfs_path
*path
, int level
)
2422 if (path
->keep_locks
)
2425 for (i
= level
; i
< BTRFS_MAX_LEVEL
; i
++) {
2426 if (!path
->nodes
[i
])
2428 if (!path
->locks
[i
])
2430 btrfs_tree_unlock_rw(path
->nodes
[i
], path
->locks
[i
]);
2436 * helper function for btrfs_search_slot. The goal is to find a block
2437 * in cache without setting the path to blocking. If we find the block
2438 * we return zero and the path is unchanged.
2440 * If we can't find the block, we set the path blocking and do some
2441 * reada. -EAGAIN is returned and the search must be repeated.
2444 read_block_for_search(struct btrfs_trans_handle
*trans
,
2445 struct btrfs_root
*root
, struct btrfs_path
*p
,
2446 struct extent_buffer
**eb_ret
, int level
, int slot
,
2447 struct btrfs_key
*key
, u64 time_seq
)
2451 struct extent_buffer
*b
= *eb_ret
;
2452 struct extent_buffer
*tmp
;
2455 blocknr
= btrfs_node_blockptr(b
, slot
);
2456 gen
= btrfs_node_ptr_generation(b
, slot
);
2458 tmp
= btrfs_find_tree_block(root
, blocknr
);
2460 /* first we do an atomic uptodate check */
2461 if (btrfs_buffer_uptodate(tmp
, gen
, 1) > 0) {
2466 /* the pages were up to date, but we failed
2467 * the generation number check. Do a full
2468 * read for the generation number that is correct.
2469 * We must do this without dropping locks so
2470 * we can trust our generation number
2472 btrfs_set_path_blocking(p
);
2474 /* now we're allowed to do a blocking uptodate check */
2475 ret
= btrfs_read_buffer(tmp
, gen
);
2480 free_extent_buffer(tmp
);
2481 btrfs_release_path(p
);
2486 * reduce lock contention at high levels
2487 * of the btree by dropping locks before
2488 * we read. Don't release the lock on the current
2489 * level because we need to walk this node to figure
2490 * out which blocks to read.
2492 btrfs_unlock_up_safe(p
, level
+ 1);
2493 btrfs_set_path_blocking(p
);
2495 free_extent_buffer(tmp
);
2497 reada_for_search(root
, p
, level
, slot
, key
->objectid
);
2499 btrfs_release_path(p
);
2502 tmp
= read_tree_block(root
, blocknr
, 0);
2505 * If the read above didn't mark this buffer up to date,
2506 * it will never end up being up to date. Set ret to EIO now
2507 * and give up so that our caller doesn't loop forever
2510 if (!btrfs_buffer_uptodate(tmp
, 0, 0))
2512 free_extent_buffer(tmp
);
2518 * helper function for btrfs_search_slot. This does all of the checks
2519 * for node-level blocks and does any balancing required based on
2522 * If no extra work was required, zero is returned. If we had to
2523 * drop the path, -EAGAIN is returned and btrfs_search_slot must
2527 setup_nodes_for_search(struct btrfs_trans_handle
*trans
,
2528 struct btrfs_root
*root
, struct btrfs_path
*p
,
2529 struct extent_buffer
*b
, int level
, int ins_len
,
2530 int *write_lock_level
)
2533 if ((p
->search_for_split
|| ins_len
> 0) && btrfs_header_nritems(b
) >=
2534 BTRFS_NODEPTRS_PER_BLOCK(root
) - 3) {
2537 if (*write_lock_level
< level
+ 1) {
2538 *write_lock_level
= level
+ 1;
2539 btrfs_release_path(p
);
2543 btrfs_set_path_blocking(p
);
2544 reada_for_balance(root
, p
, level
);
2545 sret
= split_node(trans
, root
, p
, level
);
2546 btrfs_clear_path_blocking(p
, NULL
, 0);
2553 b
= p
->nodes
[level
];
2554 } else if (ins_len
< 0 && btrfs_header_nritems(b
) <
2555 BTRFS_NODEPTRS_PER_BLOCK(root
) / 2) {
2558 if (*write_lock_level
< level
+ 1) {
2559 *write_lock_level
= level
+ 1;
2560 btrfs_release_path(p
);
2564 btrfs_set_path_blocking(p
);
2565 reada_for_balance(root
, p
, level
);
2566 sret
= balance_level(trans
, root
, p
, level
);
2567 btrfs_clear_path_blocking(p
, NULL
, 0);
2573 b
= p
->nodes
[level
];
2575 btrfs_release_path(p
);
2578 BUG_ON(btrfs_header_nritems(b
) == 1);
2588 static void key_search_validate(struct extent_buffer
*b
,
2589 struct btrfs_key
*key
,
2592 #ifdef CONFIG_BTRFS_ASSERT
2593 struct btrfs_disk_key disk_key
;
2595 btrfs_cpu_key_to_disk(&disk_key
, key
);
2598 ASSERT(!memcmp_extent_buffer(b
, &disk_key
,
2599 offsetof(struct btrfs_leaf
, items
[0].key
),
2602 ASSERT(!memcmp_extent_buffer(b
, &disk_key
,
2603 offsetof(struct btrfs_node
, ptrs
[0].key
),
2608 static int key_search(struct extent_buffer
*b
, struct btrfs_key
*key
,
2609 int level
, int *prev_cmp
, int *slot
)
2611 if (*prev_cmp
!= 0) {
2612 *prev_cmp
= bin_search(b
, key
, level
, slot
);
2616 key_search_validate(b
, key
, level
);
2622 int btrfs_find_item(struct btrfs_root
*fs_root
, struct btrfs_path
*found_path
,
2623 u64 iobjectid
, u64 ioff
, u8 key_type
,
2624 struct btrfs_key
*found_key
)
2627 struct btrfs_key key
;
2628 struct extent_buffer
*eb
;
2629 struct btrfs_path
*path
;
2631 key
.type
= key_type
;
2632 key
.objectid
= iobjectid
;
2635 if (found_path
== NULL
) {
2636 path
= btrfs_alloc_path();
2642 ret
= btrfs_search_slot(NULL
, fs_root
, &key
, path
, 0, 0);
2643 if ((ret
< 0) || (found_key
== NULL
)) {
2644 if (path
!= found_path
)
2645 btrfs_free_path(path
);
2649 eb
= path
->nodes
[0];
2650 if (ret
&& path
->slots
[0] >= btrfs_header_nritems(eb
)) {
2651 ret
= btrfs_next_leaf(fs_root
, path
);
2654 eb
= path
->nodes
[0];
2657 btrfs_item_key_to_cpu(eb
, found_key
, path
->slots
[0]);
2658 if (found_key
->type
!= key
.type
||
2659 found_key
->objectid
!= key
.objectid
)
2666 * look for key in the tree. path is filled in with nodes along the way
2667 * if key is found, we return zero and you can find the item in the leaf
2668 * level of the path (level 0)
2670 * If the key isn't found, the path points to the slot where it should
2671 * be inserted, and 1 is returned. If there are other errors during the
2672 * search a negative error number is returned.
2674 * if ins_len > 0, nodes and leaves will be split as we walk down the
2675 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
2678 int btrfs_search_slot(struct btrfs_trans_handle
*trans
, struct btrfs_root
2679 *root
, struct btrfs_key
*key
, struct btrfs_path
*p
, int
2682 struct extent_buffer
*b
;
2687 int lowest_unlock
= 1;
2689 /* everything at write_lock_level or lower must be write locked */
2690 int write_lock_level
= 0;
2691 u8 lowest_level
= 0;
2692 int min_write_lock_level
;
2695 lowest_level
= p
->lowest_level
;
2696 WARN_ON(lowest_level
&& ins_len
> 0);
2697 WARN_ON(p
->nodes
[0] != NULL
);
2698 BUG_ON(!cow
&& ins_len
);
2703 /* when we are removing items, we might have to go up to level
2704 * two as we update tree pointers Make sure we keep write
2705 * for those levels as well
2707 write_lock_level
= 2;
2708 } else if (ins_len
> 0) {
2710 * for inserting items, make sure we have a write lock on
2711 * level 1 so we can update keys
2713 write_lock_level
= 1;
2717 write_lock_level
= -1;
2719 if (cow
&& (p
->keep_locks
|| p
->lowest_level
))
2720 write_lock_level
= BTRFS_MAX_LEVEL
;
2722 min_write_lock_level
= write_lock_level
;
2727 * we try very hard to do read locks on the root
2729 root_lock
= BTRFS_READ_LOCK
;
2731 if (p
->search_commit_root
) {
2733 * the commit roots are read only
2734 * so we always do read locks
2736 if (p
->need_commit_sem
)
2737 down_read(&root
->fs_info
->commit_root_sem
);
2738 b
= root
->commit_root
;
2739 extent_buffer_get(b
);
2740 level
= btrfs_header_level(b
);
2741 if (p
->need_commit_sem
)
2742 up_read(&root
->fs_info
->commit_root_sem
);
2743 if (!p
->skip_locking
)
2744 btrfs_tree_read_lock(b
);
2746 if (p
->skip_locking
) {
2747 b
= btrfs_root_node(root
);
2748 level
= btrfs_header_level(b
);
2750 /* we don't know the level of the root node
2751 * until we actually have it read locked
2753 b
= btrfs_read_lock_root_node(root
);
2754 level
= btrfs_header_level(b
);
2755 if (level
<= write_lock_level
) {
2756 /* whoops, must trade for write lock */
2757 btrfs_tree_read_unlock(b
);
2758 free_extent_buffer(b
);
2759 b
= btrfs_lock_root_node(root
);
2760 root_lock
= BTRFS_WRITE_LOCK
;
2762 /* the level might have changed, check again */
2763 level
= btrfs_header_level(b
);
2767 p
->nodes
[level
] = b
;
2768 if (!p
->skip_locking
)
2769 p
->locks
[level
] = root_lock
;
2772 level
= btrfs_header_level(b
);
2775 * setup the path here so we can release it under lock
2776 * contention with the cow code
2780 * if we don't really need to cow this block
2781 * then we don't want to set the path blocking,
2782 * so we test it here
2784 if (!should_cow_block(trans
, root
, b
))
2788 * must have write locks on this node and the
2791 if (level
> write_lock_level
||
2792 (level
+ 1 > write_lock_level
&&
2793 level
+ 1 < BTRFS_MAX_LEVEL
&&
2794 p
->nodes
[level
+ 1])) {
2795 write_lock_level
= level
+ 1;
2796 btrfs_release_path(p
);
2800 btrfs_set_path_blocking(p
);
2801 err
= btrfs_cow_block(trans
, root
, b
,
2802 p
->nodes
[level
+ 1],
2803 p
->slots
[level
+ 1], &b
);
2810 p
->nodes
[level
] = b
;
2811 btrfs_clear_path_blocking(p
, NULL
, 0);
2814 * we have a lock on b and as long as we aren't changing
2815 * the tree, there is no way to for the items in b to change.
2816 * It is safe to drop the lock on our parent before we
2817 * go through the expensive btree search on b.
2819 * If we're inserting or deleting (ins_len != 0), then we might
2820 * be changing slot zero, which may require changing the parent.
2821 * So, we can't drop the lock until after we know which slot
2822 * we're operating on.
2824 if (!ins_len
&& !p
->keep_locks
) {
2827 if (u
< BTRFS_MAX_LEVEL
&& p
->locks
[u
]) {
2828 btrfs_tree_unlock_rw(p
->nodes
[u
], p
->locks
[u
]);
2833 ret
= key_search(b
, key
, level
, &prev_cmp
, &slot
);
2837 if (ret
&& slot
> 0) {
2841 p
->slots
[level
] = slot
;
2842 err
= setup_nodes_for_search(trans
, root
, p
, b
, level
,
2843 ins_len
, &write_lock_level
);
2850 b
= p
->nodes
[level
];
2851 slot
= p
->slots
[level
];
2854 * slot 0 is special, if we change the key
2855 * we have to update the parent pointer
2856 * which means we must have a write lock
2859 if (slot
== 0 && ins_len
&&
2860 write_lock_level
< level
+ 1) {
2861 write_lock_level
= level
+ 1;
2862 btrfs_release_path(p
);
2866 unlock_up(p
, level
, lowest_unlock
,
2867 min_write_lock_level
, &write_lock_level
);
2869 if (level
== lowest_level
) {
2875 err
= read_block_for_search(trans
, root
, p
,
2876 &b
, level
, slot
, key
, 0);
2884 if (!p
->skip_locking
) {
2885 level
= btrfs_header_level(b
);
2886 if (level
<= write_lock_level
) {
2887 err
= btrfs_try_tree_write_lock(b
);
2889 btrfs_set_path_blocking(p
);
2891 btrfs_clear_path_blocking(p
, b
,
2894 p
->locks
[level
] = BTRFS_WRITE_LOCK
;
2896 err
= btrfs_try_tree_read_lock(b
);
2898 btrfs_set_path_blocking(p
);
2899 btrfs_tree_read_lock(b
);
2900 btrfs_clear_path_blocking(p
, b
,
2903 p
->locks
[level
] = BTRFS_READ_LOCK
;
2905 p
->nodes
[level
] = b
;
2908 p
->slots
[level
] = slot
;
2910 btrfs_leaf_free_space(root
, b
) < ins_len
) {
2911 if (write_lock_level
< 1) {
2912 write_lock_level
= 1;
2913 btrfs_release_path(p
);
2917 btrfs_set_path_blocking(p
);
2918 err
= split_leaf(trans
, root
, key
,
2919 p
, ins_len
, ret
== 0);
2920 btrfs_clear_path_blocking(p
, NULL
, 0);
2928 if (!p
->search_for_split
)
2929 unlock_up(p
, level
, lowest_unlock
,
2930 min_write_lock_level
, &write_lock_level
);
2937 * we don't really know what they plan on doing with the path
2938 * from here on, so for now just mark it as blocking
2940 if (!p
->leave_spinning
)
2941 btrfs_set_path_blocking(p
);
2943 btrfs_release_path(p
);
2948 * Like btrfs_search_slot, this looks for a key in the given tree. It uses the
2949 * current state of the tree together with the operations recorded in the tree
2950 * modification log to search for the key in a previous version of this tree, as
2951 * denoted by the time_seq parameter.
2953 * Naturally, there is no support for insert, delete or cow operations.
2955 * The resulting path and return value will be set up as if we called
2956 * btrfs_search_slot at that point in time with ins_len and cow both set to 0.
2958 int btrfs_search_old_slot(struct btrfs_root
*root
, struct btrfs_key
*key
,
2959 struct btrfs_path
*p
, u64 time_seq
)
2961 struct extent_buffer
*b
;
2966 int lowest_unlock
= 1;
2967 u8 lowest_level
= 0;
2970 lowest_level
= p
->lowest_level
;
2971 WARN_ON(p
->nodes
[0] != NULL
);
2973 if (p
->search_commit_root
) {
2975 return btrfs_search_slot(NULL
, root
, key
, p
, 0, 0);
2979 b
= get_old_root(root
, time_seq
);
2980 level
= btrfs_header_level(b
);
2981 p
->locks
[level
] = BTRFS_READ_LOCK
;
2984 level
= btrfs_header_level(b
);
2985 p
->nodes
[level
] = b
;
2986 btrfs_clear_path_blocking(p
, NULL
, 0);
2989 * we have a lock on b and as long as we aren't changing
2990 * the tree, there is no way to for the items in b to change.
2991 * It is safe to drop the lock on our parent before we
2992 * go through the expensive btree search on b.
2994 btrfs_unlock_up_safe(p
, level
+ 1);
2997 * Since we can unwind eb's we want to do a real search every
3001 ret
= key_search(b
, key
, level
, &prev_cmp
, &slot
);
3005 if (ret
&& slot
> 0) {
3009 p
->slots
[level
] = slot
;
3010 unlock_up(p
, level
, lowest_unlock
, 0, NULL
);
3012 if (level
== lowest_level
) {
3018 err
= read_block_for_search(NULL
, root
, p
, &b
, level
,
3019 slot
, key
, time_seq
);
3027 level
= btrfs_header_level(b
);
3028 err
= btrfs_try_tree_read_lock(b
);
3030 btrfs_set_path_blocking(p
);
3031 btrfs_tree_read_lock(b
);
3032 btrfs_clear_path_blocking(p
, b
,
3035 b
= tree_mod_log_rewind(root
->fs_info
, p
, b
, time_seq
);
3040 p
->locks
[level
] = BTRFS_READ_LOCK
;
3041 p
->nodes
[level
] = b
;
3043 p
->slots
[level
] = slot
;
3044 unlock_up(p
, level
, lowest_unlock
, 0, NULL
);
3050 if (!p
->leave_spinning
)
3051 btrfs_set_path_blocking(p
);
3053 btrfs_release_path(p
);
3059 * helper to use instead of search slot if no exact match is needed but
3060 * instead the next or previous item should be returned.
3061 * When find_higher is true, the next higher item is returned, the next lower
3063 * When return_any and find_higher are both true, and no higher item is found,
3064 * return the next lower instead.
3065 * When return_any is true and find_higher is false, and no lower item is found,
3066 * return the next higher instead.
3067 * It returns 0 if any item is found, 1 if none is found (tree empty), and
3070 int btrfs_search_slot_for_read(struct btrfs_root
*root
,
3071 struct btrfs_key
*key
, struct btrfs_path
*p
,
3072 int find_higher
, int return_any
)
3075 struct extent_buffer
*leaf
;
3078 ret
= btrfs_search_slot(NULL
, root
, key
, p
, 0, 0);
3082 * a return value of 1 means the path is at the position where the
3083 * item should be inserted. Normally this is the next bigger item,
3084 * but in case the previous item is the last in a leaf, path points
3085 * to the first free slot in the previous leaf, i.e. at an invalid
3091 if (p
->slots
[0] >= btrfs_header_nritems(leaf
)) {
3092 ret
= btrfs_next_leaf(root
, p
);
3098 * no higher item found, return the next
3103 btrfs_release_path(p
);
3107 if (p
->slots
[0] == 0) {
3108 ret
= btrfs_prev_leaf(root
, p
);
3113 if (p
->slots
[0] == btrfs_header_nritems(leaf
))
3120 * no lower item found, return the next
3125 btrfs_release_path(p
);
3135 * adjust the pointers going up the tree, starting at level
3136 * making sure the right key of each node is points to 'key'.
3137 * This is used after shifting pointers to the left, so it stops
3138 * fixing up pointers when a given leaf/node is not in slot 0 of the
3142 static void fixup_low_keys(struct btrfs_root
*root
, struct btrfs_path
*path
,
3143 struct btrfs_disk_key
*key
, int level
)
3146 struct extent_buffer
*t
;
3148 for (i
= level
; i
< BTRFS_MAX_LEVEL
; i
++) {
3149 int tslot
= path
->slots
[i
];
3150 if (!path
->nodes
[i
])
3153 tree_mod_log_set_node_key(root
->fs_info
, t
, tslot
, 1);
3154 btrfs_set_node_key(t
, key
, tslot
);
3155 btrfs_mark_buffer_dirty(path
->nodes
[i
]);
3164 * This function isn't completely safe. It's the caller's responsibility
3165 * that the new key won't break the order
3167 void btrfs_set_item_key_safe(struct btrfs_root
*root
, struct btrfs_path
*path
,
3168 struct btrfs_key
*new_key
)
3170 struct btrfs_disk_key disk_key
;
3171 struct extent_buffer
*eb
;
3174 eb
= path
->nodes
[0];
3175 slot
= path
->slots
[0];
3177 btrfs_item_key(eb
, &disk_key
, slot
- 1);
3178 BUG_ON(comp_keys(&disk_key
, new_key
) >= 0);
3180 if (slot
< btrfs_header_nritems(eb
) - 1) {
3181 btrfs_item_key(eb
, &disk_key
, slot
+ 1);
3182 BUG_ON(comp_keys(&disk_key
, new_key
) <= 0);
3185 btrfs_cpu_key_to_disk(&disk_key
, new_key
);
3186 btrfs_set_item_key(eb
, &disk_key
, slot
);
3187 btrfs_mark_buffer_dirty(eb
);
3189 fixup_low_keys(root
, path
, &disk_key
, 1);
3193 * try to push data from one node into the next node left in the
3196 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
3197 * error, and > 0 if there was no room in the left hand block.
3199 static int push_node_left(struct btrfs_trans_handle
*trans
,
3200 struct btrfs_root
*root
, struct extent_buffer
*dst
,
3201 struct extent_buffer
*src
, int empty
)
3208 src_nritems
= btrfs_header_nritems(src
);
3209 dst_nritems
= btrfs_header_nritems(dst
);
3210 push_items
= BTRFS_NODEPTRS_PER_BLOCK(root
) - dst_nritems
;
3211 WARN_ON(btrfs_header_generation(src
) != trans
->transid
);
3212 WARN_ON(btrfs_header_generation(dst
) != trans
->transid
);
3214 if (!empty
&& src_nritems
<= 8)
3217 if (push_items
<= 0)
3221 push_items
= min(src_nritems
, push_items
);
3222 if (push_items
< src_nritems
) {
3223 /* leave at least 8 pointers in the node if
3224 * we aren't going to empty it
3226 if (src_nritems
- push_items
< 8) {
3227 if (push_items
<= 8)
3233 push_items
= min(src_nritems
- 8, push_items
);
3235 ret
= tree_mod_log_eb_copy(root
->fs_info
, dst
, src
, dst_nritems
, 0,
3238 btrfs_abort_transaction(trans
, root
, ret
);
3241 copy_extent_buffer(dst
, src
,
3242 btrfs_node_key_ptr_offset(dst_nritems
),
3243 btrfs_node_key_ptr_offset(0),
3244 push_items
* sizeof(struct btrfs_key_ptr
));
3246 if (push_items
< src_nritems
) {
3248 * don't call tree_mod_log_eb_move here, key removal was already
3249 * fully logged by tree_mod_log_eb_copy above.
3251 memmove_extent_buffer(src
, btrfs_node_key_ptr_offset(0),
3252 btrfs_node_key_ptr_offset(push_items
),
3253 (src_nritems
- push_items
) *
3254 sizeof(struct btrfs_key_ptr
));
3256 btrfs_set_header_nritems(src
, src_nritems
- push_items
);
3257 btrfs_set_header_nritems(dst
, dst_nritems
+ push_items
);
3258 btrfs_mark_buffer_dirty(src
);
3259 btrfs_mark_buffer_dirty(dst
);
3265 * try to push data from one node into the next node right in the
3268 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
3269 * error, and > 0 if there was no room in the right hand block.
3271 * this will only push up to 1/2 the contents of the left node over
3273 static int balance_node_right(struct btrfs_trans_handle
*trans
,
3274 struct btrfs_root
*root
,
3275 struct extent_buffer
*dst
,
3276 struct extent_buffer
*src
)
3284 WARN_ON(btrfs_header_generation(src
) != trans
->transid
);
3285 WARN_ON(btrfs_header_generation(dst
) != trans
->transid
);
3287 src_nritems
= btrfs_header_nritems(src
);
3288 dst_nritems
= btrfs_header_nritems(dst
);
3289 push_items
= BTRFS_NODEPTRS_PER_BLOCK(root
) - dst_nritems
;
3290 if (push_items
<= 0)
3293 if (src_nritems
< 4)
3296 max_push
= src_nritems
/ 2 + 1;
3297 /* don't try to empty the node */
3298 if (max_push
>= src_nritems
)
3301 if (max_push
< push_items
)
3302 push_items
= max_push
;
3304 tree_mod_log_eb_move(root
->fs_info
, dst
, push_items
, 0, dst_nritems
);
3305 memmove_extent_buffer(dst
, btrfs_node_key_ptr_offset(push_items
),
3306 btrfs_node_key_ptr_offset(0),
3308 sizeof(struct btrfs_key_ptr
));
3310 ret
= tree_mod_log_eb_copy(root
->fs_info
, dst
, src
, 0,
3311 src_nritems
- push_items
, push_items
);
3313 btrfs_abort_transaction(trans
, root
, ret
);
3316 copy_extent_buffer(dst
, src
,
3317 btrfs_node_key_ptr_offset(0),
3318 btrfs_node_key_ptr_offset(src_nritems
- push_items
),
3319 push_items
* sizeof(struct btrfs_key_ptr
));
3321 btrfs_set_header_nritems(src
, src_nritems
- push_items
);
3322 btrfs_set_header_nritems(dst
, dst_nritems
+ push_items
);
3324 btrfs_mark_buffer_dirty(src
);
3325 btrfs_mark_buffer_dirty(dst
);
3331 * helper function to insert a new root level in the tree.
3332 * A new node is allocated, and a single item is inserted to
3333 * point to the existing root
3335 * returns zero on success or < 0 on failure.
3337 static noinline
int insert_new_root(struct btrfs_trans_handle
*trans
,
3338 struct btrfs_root
*root
,
3339 struct btrfs_path
*path
, int level
)
3342 struct extent_buffer
*lower
;
3343 struct extent_buffer
*c
;
3344 struct extent_buffer
*old
;
3345 struct btrfs_disk_key lower_key
;
3347 BUG_ON(path
->nodes
[level
]);
3348 BUG_ON(path
->nodes
[level
-1] != root
->node
);
3350 lower
= path
->nodes
[level
-1];
3352 btrfs_item_key(lower
, &lower_key
, 0);
3354 btrfs_node_key(lower
, &lower_key
, 0);
3356 c
= btrfs_alloc_tree_block(trans
, root
, 0, root
->root_key
.objectid
,
3357 &lower_key
, level
, root
->node
->start
, 0);
3361 root_add_used(root
, root
->nodesize
);
3363 memset_extent_buffer(c
, 0, 0, sizeof(struct btrfs_header
));
3364 btrfs_set_header_nritems(c
, 1);
3365 btrfs_set_header_level(c
, level
);
3366 btrfs_set_header_bytenr(c
, c
->start
);
3367 btrfs_set_header_generation(c
, trans
->transid
);
3368 btrfs_set_header_backref_rev(c
, BTRFS_MIXED_BACKREF_REV
);
3369 btrfs_set_header_owner(c
, root
->root_key
.objectid
);
3371 write_extent_buffer(c
, root
->fs_info
->fsid
, btrfs_header_fsid(),
3374 write_extent_buffer(c
, root
->fs_info
->chunk_tree_uuid
,
3375 btrfs_header_chunk_tree_uuid(c
), BTRFS_UUID_SIZE
);
3377 btrfs_set_node_key(c
, &lower_key
, 0);
3378 btrfs_set_node_blockptr(c
, 0, lower
->start
);
3379 lower_gen
= btrfs_header_generation(lower
);
3380 WARN_ON(lower_gen
!= trans
->transid
);
3382 btrfs_set_node_ptr_generation(c
, 0, lower_gen
);
3384 btrfs_mark_buffer_dirty(c
);
3387 tree_mod_log_set_root_pointer(root
, c
, 0);
3388 rcu_assign_pointer(root
->node
, c
);
3390 /* the super has an extra ref to root->node */
3391 free_extent_buffer(old
);
3393 add_root_to_dirty_list(root
);
3394 extent_buffer_get(c
);
3395 path
->nodes
[level
] = c
;
3396 path
->locks
[level
] = BTRFS_WRITE_LOCK
;
3397 path
->slots
[level
] = 0;
3402 * worker function to insert a single pointer in a node.
3403 * the node should have enough room for the pointer already
3405 * slot and level indicate where you want the key to go, and
3406 * blocknr is the block the key points to.
3408 static void insert_ptr(struct btrfs_trans_handle
*trans
,
3409 struct btrfs_root
*root
, struct btrfs_path
*path
,
3410 struct btrfs_disk_key
*key
, u64 bytenr
,
3411 int slot
, int level
)
3413 struct extent_buffer
*lower
;
3417 BUG_ON(!path
->nodes
[level
]);
3418 btrfs_assert_tree_locked(path
->nodes
[level
]);
3419 lower
= path
->nodes
[level
];
3420 nritems
= btrfs_header_nritems(lower
);
3421 BUG_ON(slot
> nritems
);
3422 BUG_ON(nritems
== BTRFS_NODEPTRS_PER_BLOCK(root
));
3423 if (slot
!= nritems
) {
3425 tree_mod_log_eb_move(root
->fs_info
, lower
, slot
+ 1,
3426 slot
, nritems
- slot
);
3427 memmove_extent_buffer(lower
,
3428 btrfs_node_key_ptr_offset(slot
+ 1),
3429 btrfs_node_key_ptr_offset(slot
),
3430 (nritems
- slot
) * sizeof(struct btrfs_key_ptr
));
3433 ret
= tree_mod_log_insert_key(root
->fs_info
, lower
, slot
,
3434 MOD_LOG_KEY_ADD
, GFP_NOFS
);
3437 btrfs_set_node_key(lower
, key
, slot
);
3438 btrfs_set_node_blockptr(lower
, slot
, bytenr
);
3439 WARN_ON(trans
->transid
== 0);
3440 btrfs_set_node_ptr_generation(lower
, slot
, trans
->transid
);
3441 btrfs_set_header_nritems(lower
, nritems
+ 1);
3442 btrfs_mark_buffer_dirty(lower
);
3446 * split the node at the specified level in path in two.
3447 * The path is corrected to point to the appropriate node after the split
3449 * Before splitting this tries to make some room in the node by pushing
3450 * left and right, if either one works, it returns right away.
3452 * returns 0 on success and < 0 on failure
3454 static noinline
int split_node(struct btrfs_trans_handle
*trans
,
3455 struct btrfs_root
*root
,
3456 struct btrfs_path
*path
, int level
)
3458 struct extent_buffer
*c
;
3459 struct extent_buffer
*split
;
3460 struct btrfs_disk_key disk_key
;
3465 c
= path
->nodes
[level
];
3466 WARN_ON(btrfs_header_generation(c
) != trans
->transid
);
3467 if (c
== root
->node
) {
3469 * trying to split the root, lets make a new one
3471 * tree mod log: We don't log_removal old root in
3472 * insert_new_root, because that root buffer will be kept as a
3473 * normal node. We are going to log removal of half of the
3474 * elements below with tree_mod_log_eb_copy. We're holding a
3475 * tree lock on the buffer, which is why we cannot race with
3476 * other tree_mod_log users.
3478 ret
= insert_new_root(trans
, root
, path
, level
+ 1);
3482 ret
= push_nodes_for_insert(trans
, root
, path
, level
);
3483 c
= path
->nodes
[level
];
3484 if (!ret
&& btrfs_header_nritems(c
) <
3485 BTRFS_NODEPTRS_PER_BLOCK(root
) - 3)
3491 c_nritems
= btrfs_header_nritems(c
);
3492 mid
= (c_nritems
+ 1) / 2;
3493 btrfs_node_key(c
, &disk_key
, mid
);
3495 split
= btrfs_alloc_tree_block(trans
, root
, 0, root
->root_key
.objectid
,
3496 &disk_key
, level
, c
->start
, 0);
3498 return PTR_ERR(split
);
3500 root_add_used(root
, root
->nodesize
);
3502 memset_extent_buffer(split
, 0, 0, sizeof(struct btrfs_header
));
3503 btrfs_set_header_level(split
, btrfs_header_level(c
));
3504 btrfs_set_header_bytenr(split
, split
->start
);
3505 btrfs_set_header_generation(split
, trans
->transid
);
3506 btrfs_set_header_backref_rev(split
, BTRFS_MIXED_BACKREF_REV
);
3507 btrfs_set_header_owner(split
, root
->root_key
.objectid
);
3508 write_extent_buffer(split
, root
->fs_info
->fsid
,
3509 btrfs_header_fsid(), BTRFS_FSID_SIZE
);
3510 write_extent_buffer(split
, root
->fs_info
->chunk_tree_uuid
,
3511 btrfs_header_chunk_tree_uuid(split
),
3514 ret
= tree_mod_log_eb_copy(root
->fs_info
, split
, c
, 0,
3515 mid
, c_nritems
- mid
);
3517 btrfs_abort_transaction(trans
, root
, ret
);
3520 copy_extent_buffer(split
, c
,
3521 btrfs_node_key_ptr_offset(0),
3522 btrfs_node_key_ptr_offset(mid
),
3523 (c_nritems
- mid
) * sizeof(struct btrfs_key_ptr
));
3524 btrfs_set_header_nritems(split
, c_nritems
- mid
);
3525 btrfs_set_header_nritems(c
, mid
);
3528 btrfs_mark_buffer_dirty(c
);
3529 btrfs_mark_buffer_dirty(split
);
3531 insert_ptr(trans
, root
, path
, &disk_key
, split
->start
,
3532 path
->slots
[level
+ 1] + 1, level
+ 1);
3534 if (path
->slots
[level
] >= mid
) {
3535 path
->slots
[level
] -= mid
;
3536 btrfs_tree_unlock(c
);
3537 free_extent_buffer(c
);
3538 path
->nodes
[level
] = split
;
3539 path
->slots
[level
+ 1] += 1;
3541 btrfs_tree_unlock(split
);
3542 free_extent_buffer(split
);
3548 * how many bytes are required to store the items in a leaf. start
3549 * and nr indicate which items in the leaf to check. This totals up the
3550 * space used both by the item structs and the item data
3552 static int leaf_space_used(struct extent_buffer
*l
, int start
, int nr
)
3554 struct btrfs_item
*start_item
;
3555 struct btrfs_item
*end_item
;
3556 struct btrfs_map_token token
;
3558 int nritems
= btrfs_header_nritems(l
);
3559 int end
= min(nritems
, start
+ nr
) - 1;
3563 btrfs_init_map_token(&token
);
3564 start_item
= btrfs_item_nr(start
);
3565 end_item
= btrfs_item_nr(end
);
3566 data_len
= btrfs_token_item_offset(l
, start_item
, &token
) +
3567 btrfs_token_item_size(l
, start_item
, &token
);
3568 data_len
= data_len
- btrfs_token_item_offset(l
, end_item
, &token
);
3569 data_len
+= sizeof(struct btrfs_item
) * nr
;
3570 WARN_ON(data_len
< 0);
3575 * The space between the end of the leaf items and
3576 * the start of the leaf data. IOW, how much room
3577 * the leaf has left for both items and data
3579 noinline
int btrfs_leaf_free_space(struct btrfs_root
*root
,
3580 struct extent_buffer
*leaf
)
3582 int nritems
= btrfs_header_nritems(leaf
);
3584 ret
= BTRFS_LEAF_DATA_SIZE(root
) - leaf_space_used(leaf
, 0, nritems
);
3586 btrfs_crit(root
->fs_info
,
3587 "leaf free space ret %d, leaf data size %lu, used %d nritems %d",
3588 ret
, (unsigned long) BTRFS_LEAF_DATA_SIZE(root
),
3589 leaf_space_used(leaf
, 0, nritems
), nritems
);
3595 * min slot controls the lowest index we're willing to push to the
3596 * right. We'll push up to and including min_slot, but no lower
3598 static noinline
int __push_leaf_right(struct btrfs_trans_handle
*trans
,
3599 struct btrfs_root
*root
,
3600 struct btrfs_path
*path
,
3601 int data_size
, int empty
,
3602 struct extent_buffer
*right
,
3603 int free_space
, u32 left_nritems
,
3606 struct extent_buffer
*left
= path
->nodes
[0];
3607 struct extent_buffer
*upper
= path
->nodes
[1];
3608 struct btrfs_map_token token
;
3609 struct btrfs_disk_key disk_key
;
3614 struct btrfs_item
*item
;
3620 btrfs_init_map_token(&token
);
3625 nr
= max_t(u32
, 1, min_slot
);
3627 if (path
->slots
[0] >= left_nritems
)
3628 push_space
+= data_size
;
3630 slot
= path
->slots
[1];
3631 i
= left_nritems
- 1;
3633 item
= btrfs_item_nr(i
);
3635 if (!empty
&& push_items
> 0) {
3636 if (path
->slots
[0] > i
)
3638 if (path
->slots
[0] == i
) {
3639 int space
= btrfs_leaf_free_space(root
, left
);
3640 if (space
+ push_space
* 2 > free_space
)
3645 if (path
->slots
[0] == i
)
3646 push_space
+= data_size
;
3648 this_item_size
= btrfs_item_size(left
, item
);
3649 if (this_item_size
+ sizeof(*item
) + push_space
> free_space
)
3653 push_space
+= this_item_size
+ sizeof(*item
);
3659 if (push_items
== 0)
3662 WARN_ON(!empty
&& push_items
== left_nritems
);
3664 /* push left to right */
3665 right_nritems
= btrfs_header_nritems(right
);
3667 push_space
= btrfs_item_end_nr(left
, left_nritems
- push_items
);
3668 push_space
-= leaf_data_end(root
, left
);
3670 /* make room in the right data area */
3671 data_end
= leaf_data_end(root
, right
);
3672 memmove_extent_buffer(right
,
3673 btrfs_leaf_data(right
) + data_end
- push_space
,
3674 btrfs_leaf_data(right
) + data_end
,
3675 BTRFS_LEAF_DATA_SIZE(root
) - data_end
);
3677 /* copy from the left data area */
3678 copy_extent_buffer(right
, left
, btrfs_leaf_data(right
) +
3679 BTRFS_LEAF_DATA_SIZE(root
) - push_space
,
3680 btrfs_leaf_data(left
) + leaf_data_end(root
, left
),
3683 memmove_extent_buffer(right
, btrfs_item_nr_offset(push_items
),
3684 btrfs_item_nr_offset(0),
3685 right_nritems
* sizeof(struct btrfs_item
));
3687 /* copy the items from left to right */
3688 copy_extent_buffer(right
, left
, btrfs_item_nr_offset(0),
3689 btrfs_item_nr_offset(left_nritems
- push_items
),
3690 push_items
* sizeof(struct btrfs_item
));
3692 /* update the item pointers */
3693 right_nritems
+= push_items
;
3694 btrfs_set_header_nritems(right
, right_nritems
);
3695 push_space
= BTRFS_LEAF_DATA_SIZE(root
);
3696 for (i
= 0; i
< right_nritems
; i
++) {
3697 item
= btrfs_item_nr(i
);
3698 push_space
-= btrfs_token_item_size(right
, item
, &token
);
3699 btrfs_set_token_item_offset(right
, item
, push_space
, &token
);
3702 left_nritems
-= push_items
;
3703 btrfs_set_header_nritems(left
, left_nritems
);
3706 btrfs_mark_buffer_dirty(left
);
3708 clean_tree_block(trans
, root
, left
);
3710 btrfs_mark_buffer_dirty(right
);
3712 btrfs_item_key(right
, &disk_key
, 0);
3713 btrfs_set_node_key(upper
, &disk_key
, slot
+ 1);
3714 btrfs_mark_buffer_dirty(upper
);
3716 /* then fixup the leaf pointer in the path */
3717 if (path
->slots
[0] >= left_nritems
) {
3718 path
->slots
[0] -= left_nritems
;
3719 if (btrfs_header_nritems(path
->nodes
[0]) == 0)
3720 clean_tree_block(trans
, root
, path
->nodes
[0]);
3721 btrfs_tree_unlock(path
->nodes
[0]);
3722 free_extent_buffer(path
->nodes
[0]);
3723 path
->nodes
[0] = right
;
3724 path
->slots
[1] += 1;
3726 btrfs_tree_unlock(right
);
3727 free_extent_buffer(right
);
3732 btrfs_tree_unlock(right
);
3733 free_extent_buffer(right
);
3738 * push some data in the path leaf to the right, trying to free up at
3739 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3741 * returns 1 if the push failed because the other node didn't have enough
3742 * room, 0 if everything worked out and < 0 if there were major errors.
3744 * this will push starting from min_slot to the end of the leaf. It won't
3745 * push any slot lower than min_slot
3747 static int push_leaf_right(struct btrfs_trans_handle
*trans
, struct btrfs_root
3748 *root
, struct btrfs_path
*path
,
3749 int min_data_size
, int data_size
,
3750 int empty
, u32 min_slot
)
3752 struct extent_buffer
*left
= path
->nodes
[0];
3753 struct extent_buffer
*right
;
3754 struct extent_buffer
*upper
;
3760 if (!path
->nodes
[1])
3763 slot
= path
->slots
[1];
3764 upper
= path
->nodes
[1];
3765 if (slot
>= btrfs_header_nritems(upper
) - 1)
3768 btrfs_assert_tree_locked(path
->nodes
[1]);
3770 right
= read_node_slot(root
, upper
, slot
+ 1);
3774 btrfs_tree_lock(right
);
3775 btrfs_set_lock_blocking(right
);
3777 free_space
= btrfs_leaf_free_space(root
, right
);
3778 if (free_space
< data_size
)
3781 /* cow and double check */
3782 ret
= btrfs_cow_block(trans
, root
, right
, upper
,
3787 free_space
= btrfs_leaf_free_space(root
, right
);
3788 if (free_space
< data_size
)
3791 left_nritems
= btrfs_header_nritems(left
);
3792 if (left_nritems
== 0)
3795 if (path
->slots
[0] == left_nritems
&& !empty
) {
3796 /* Key greater than all keys in the leaf, right neighbor has
3797 * enough room for it and we're not emptying our leaf to delete
3798 * it, therefore use right neighbor to insert the new item and
3799 * no need to touch/dirty our left leaft. */
3800 btrfs_tree_unlock(left
);
3801 free_extent_buffer(left
);
3802 path
->nodes
[0] = right
;
3808 return __push_leaf_right(trans
, root
, path
, min_data_size
, empty
,
3809 right
, free_space
, left_nritems
, min_slot
);
3811 btrfs_tree_unlock(right
);
3812 free_extent_buffer(right
);
3817 * push some data in the path leaf to the left, trying to free up at
3818 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3820 * max_slot can put a limit on how far into the leaf we'll push items. The
3821 * item at 'max_slot' won't be touched. Use (u32)-1 to make us do all the
3824 static noinline
int __push_leaf_left(struct btrfs_trans_handle
*trans
,
3825 struct btrfs_root
*root
,
3826 struct btrfs_path
*path
, int data_size
,
3827 int empty
, struct extent_buffer
*left
,
3828 int free_space
, u32 right_nritems
,
3831 struct btrfs_disk_key disk_key
;
3832 struct extent_buffer
*right
= path
->nodes
[0];
3836 struct btrfs_item
*item
;
3837 u32 old_left_nritems
;
3841 u32 old_left_item_size
;
3842 struct btrfs_map_token token
;
3844 btrfs_init_map_token(&token
);
3847 nr
= min(right_nritems
, max_slot
);
3849 nr
= min(right_nritems
- 1, max_slot
);
3851 for (i
= 0; i
< nr
; i
++) {
3852 item
= btrfs_item_nr(i
);
3854 if (!empty
&& push_items
> 0) {
3855 if (path
->slots
[0] < i
)
3857 if (path
->slots
[0] == i
) {
3858 int space
= btrfs_leaf_free_space(root
, right
);
3859 if (space
+ push_space
* 2 > free_space
)
3864 if (path
->slots
[0] == i
)
3865 push_space
+= data_size
;
3867 this_item_size
= btrfs_item_size(right
, item
);
3868 if (this_item_size
+ sizeof(*item
) + push_space
> free_space
)
3872 push_space
+= this_item_size
+ sizeof(*item
);
3875 if (push_items
== 0) {
3879 WARN_ON(!empty
&& push_items
== btrfs_header_nritems(right
));
3881 /* push data from right to left */
3882 copy_extent_buffer(left
, right
,
3883 btrfs_item_nr_offset(btrfs_header_nritems(left
)),
3884 btrfs_item_nr_offset(0),
3885 push_items
* sizeof(struct btrfs_item
));
3887 push_space
= BTRFS_LEAF_DATA_SIZE(root
) -
3888 btrfs_item_offset_nr(right
, push_items
- 1);
3890 copy_extent_buffer(left
, right
, btrfs_leaf_data(left
) +
3891 leaf_data_end(root
, left
) - push_space
,
3892 btrfs_leaf_data(right
) +
3893 btrfs_item_offset_nr(right
, push_items
- 1),
3895 old_left_nritems
= btrfs_header_nritems(left
);
3896 BUG_ON(old_left_nritems
<= 0);
3898 old_left_item_size
= btrfs_item_offset_nr(left
, old_left_nritems
- 1);
3899 for (i
= old_left_nritems
; i
< old_left_nritems
+ push_items
; i
++) {
3902 item
= btrfs_item_nr(i
);
3904 ioff
= btrfs_token_item_offset(left
, item
, &token
);
3905 btrfs_set_token_item_offset(left
, item
,
3906 ioff
- (BTRFS_LEAF_DATA_SIZE(root
) - old_left_item_size
),
3909 btrfs_set_header_nritems(left
, old_left_nritems
+ push_items
);
3911 /* fixup right node */
3912 if (push_items
> right_nritems
)
3913 WARN(1, KERN_CRIT
"push items %d nr %u\n", push_items
,
3916 if (push_items
< right_nritems
) {
3917 push_space
= btrfs_item_offset_nr(right
, push_items
- 1) -
3918 leaf_data_end(root
, right
);
3919 memmove_extent_buffer(right
, btrfs_leaf_data(right
) +
3920 BTRFS_LEAF_DATA_SIZE(root
) - push_space
,
3921 btrfs_leaf_data(right
) +
3922 leaf_data_end(root
, right
), push_space
);
3924 memmove_extent_buffer(right
, btrfs_item_nr_offset(0),
3925 btrfs_item_nr_offset(push_items
),
3926 (btrfs_header_nritems(right
) - push_items
) *
3927 sizeof(struct btrfs_item
));
3929 right_nritems
-= push_items
;
3930 btrfs_set_header_nritems(right
, right_nritems
);
3931 push_space
= BTRFS_LEAF_DATA_SIZE(root
);
3932 for (i
= 0; i
< right_nritems
; i
++) {
3933 item
= btrfs_item_nr(i
);
3935 push_space
= push_space
- btrfs_token_item_size(right
,
3937 btrfs_set_token_item_offset(right
, item
, push_space
, &token
);
3940 btrfs_mark_buffer_dirty(left
);
3942 btrfs_mark_buffer_dirty(right
);
3944 clean_tree_block(trans
, root
, right
);
3946 btrfs_item_key(right
, &disk_key
, 0);
3947 fixup_low_keys(root
, path
, &disk_key
, 1);
3949 /* then fixup the leaf pointer in the path */
3950 if (path
->slots
[0] < push_items
) {
3951 path
->slots
[0] += old_left_nritems
;
3952 btrfs_tree_unlock(path
->nodes
[0]);
3953 free_extent_buffer(path
->nodes
[0]);
3954 path
->nodes
[0] = left
;
3955 path
->slots
[1] -= 1;
3957 btrfs_tree_unlock(left
);
3958 free_extent_buffer(left
);
3959 path
->slots
[0] -= push_items
;
3961 BUG_ON(path
->slots
[0] < 0);
3964 btrfs_tree_unlock(left
);
3965 free_extent_buffer(left
);
3970 * push some data in the path leaf to the left, trying to free up at
3971 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3973 * max_slot can put a limit on how far into the leaf we'll push items. The
3974 * item at 'max_slot' won't be touched. Use (u32)-1 to make us push all the
3977 static int push_leaf_left(struct btrfs_trans_handle
*trans
, struct btrfs_root
3978 *root
, struct btrfs_path
*path
, int min_data_size
,
3979 int data_size
, int empty
, u32 max_slot
)
3981 struct extent_buffer
*right
= path
->nodes
[0];
3982 struct extent_buffer
*left
;
3988 slot
= path
->slots
[1];
3991 if (!path
->nodes
[1])
3994 right_nritems
= btrfs_header_nritems(right
);
3995 if (right_nritems
== 0)
3998 btrfs_assert_tree_locked(path
->nodes
[1]);
4000 left
= read_node_slot(root
, path
->nodes
[1], slot
- 1);
4004 btrfs_tree_lock(left
);
4005 btrfs_set_lock_blocking(left
);
4007 free_space
= btrfs_leaf_free_space(root
, left
);
4008 if (free_space
< data_size
) {
4013 /* cow and double check */
4014 ret
= btrfs_cow_block(trans
, root
, left
,
4015 path
->nodes
[1], slot
- 1, &left
);
4017 /* we hit -ENOSPC, but it isn't fatal here */
4023 free_space
= btrfs_leaf_free_space(root
, left
);
4024 if (free_space
< data_size
) {
4029 return __push_leaf_left(trans
, root
, path
, min_data_size
,
4030 empty
, left
, free_space
, right_nritems
,
4033 btrfs_tree_unlock(left
);
4034 free_extent_buffer(left
);
4039 * split the path's leaf in two, making sure there is at least data_size
4040 * available for the resulting leaf level of the path.
4042 static noinline
void copy_for_split(struct btrfs_trans_handle
*trans
,
4043 struct btrfs_root
*root
,
4044 struct btrfs_path
*path
,
4045 struct extent_buffer
*l
,
4046 struct extent_buffer
*right
,
4047 int slot
, int mid
, int nritems
)
4052 struct btrfs_disk_key disk_key
;
4053 struct btrfs_map_token token
;
4055 btrfs_init_map_token(&token
);
4057 nritems
= nritems
- mid
;
4058 btrfs_set_header_nritems(right
, nritems
);
4059 data_copy_size
= btrfs_item_end_nr(l
, mid
) - leaf_data_end(root
, l
);
4061 copy_extent_buffer(right
, l
, btrfs_item_nr_offset(0),
4062 btrfs_item_nr_offset(mid
),
4063 nritems
* sizeof(struct btrfs_item
));
4065 copy_extent_buffer(right
, l
,
4066 btrfs_leaf_data(right
) + BTRFS_LEAF_DATA_SIZE(root
) -
4067 data_copy_size
, btrfs_leaf_data(l
) +
4068 leaf_data_end(root
, l
), data_copy_size
);
4070 rt_data_off
= BTRFS_LEAF_DATA_SIZE(root
) -
4071 btrfs_item_end_nr(l
, mid
);
4073 for (i
= 0; i
< nritems
; i
++) {
4074 struct btrfs_item
*item
= btrfs_item_nr(i
);
4077 ioff
= btrfs_token_item_offset(right
, item
, &token
);
4078 btrfs_set_token_item_offset(right
, item
,
4079 ioff
+ rt_data_off
, &token
);
4082 btrfs_set_header_nritems(l
, mid
);
4083 btrfs_item_key(right
, &disk_key
, 0);
4084 insert_ptr(trans
, root
, path
, &disk_key
, right
->start
,
4085 path
->slots
[1] + 1, 1);
4087 btrfs_mark_buffer_dirty(right
);
4088 btrfs_mark_buffer_dirty(l
);
4089 BUG_ON(path
->slots
[0] != slot
);
4092 btrfs_tree_unlock(path
->nodes
[0]);
4093 free_extent_buffer(path
->nodes
[0]);
4094 path
->nodes
[0] = right
;
4095 path
->slots
[0] -= mid
;
4096 path
->slots
[1] += 1;
4098 btrfs_tree_unlock(right
);
4099 free_extent_buffer(right
);
4102 BUG_ON(path
->slots
[0] < 0);
4106 * double splits happen when we need to insert a big item in the middle
4107 * of a leaf. A double split can leave us with 3 mostly empty leaves:
4108 * leaf: [ slots 0 - N] [ our target ] [ N + 1 - total in leaf ]
4111 * We avoid this by trying to push the items on either side of our target
4112 * into the adjacent leaves. If all goes well we can avoid the double split
4115 static noinline
int push_for_double_split(struct btrfs_trans_handle
*trans
,
4116 struct btrfs_root
*root
,
4117 struct btrfs_path
*path
,
4124 int space_needed
= data_size
;
4126 slot
= path
->slots
[0];
4127 if (slot
< btrfs_header_nritems(path
->nodes
[0]))
4128 space_needed
-= btrfs_leaf_free_space(root
, path
->nodes
[0]);
4131 * try to push all the items after our slot into the
4134 ret
= push_leaf_right(trans
, root
, path
, 1, space_needed
, 0, slot
);
4141 nritems
= btrfs_header_nritems(path
->nodes
[0]);
4143 * our goal is to get our slot at the start or end of a leaf. If
4144 * we've done so we're done
4146 if (path
->slots
[0] == 0 || path
->slots
[0] == nritems
)
4149 if (btrfs_leaf_free_space(root
, path
->nodes
[0]) >= data_size
)
4152 /* try to push all the items before our slot into the next leaf */
4153 slot
= path
->slots
[0];
4154 ret
= push_leaf_left(trans
, root
, path
, 1, space_needed
, 0, slot
);
4167 * split the path's leaf in two, making sure there is at least data_size
4168 * available for the resulting leaf level of the path.
4170 * returns 0 if all went well and < 0 on failure.
4172 static noinline
int split_leaf(struct btrfs_trans_handle
*trans
,
4173 struct btrfs_root
*root
,
4174 struct btrfs_key
*ins_key
,
4175 struct btrfs_path
*path
, int data_size
,
4178 struct btrfs_disk_key disk_key
;
4179 struct extent_buffer
*l
;
4183 struct extent_buffer
*right
;
4187 int num_doubles
= 0;
4188 int tried_avoid_double
= 0;
4191 slot
= path
->slots
[0];
4192 if (extend
&& data_size
+ btrfs_item_size_nr(l
, slot
) +
4193 sizeof(struct btrfs_item
) > BTRFS_LEAF_DATA_SIZE(root
))
4196 /* first try to make some room by pushing left and right */
4197 if (data_size
&& path
->nodes
[1]) {
4198 int space_needed
= data_size
;
4200 if (slot
< btrfs_header_nritems(l
))
4201 space_needed
-= btrfs_leaf_free_space(root
, l
);
4203 wret
= push_leaf_right(trans
, root
, path
, space_needed
,
4204 space_needed
, 0, 0);
4208 wret
= push_leaf_left(trans
, root
, path
, space_needed
,
4209 space_needed
, 0, (u32
)-1);
4215 /* did the pushes work? */
4216 if (btrfs_leaf_free_space(root
, l
) >= data_size
)
4220 if (!path
->nodes
[1]) {
4221 ret
= insert_new_root(trans
, root
, path
, 1);
4228 slot
= path
->slots
[0];
4229 nritems
= btrfs_header_nritems(l
);
4230 mid
= (nritems
+ 1) / 2;
4234 leaf_space_used(l
, mid
, nritems
- mid
) + data_size
>
4235 BTRFS_LEAF_DATA_SIZE(root
)) {
4236 if (slot
>= nritems
) {
4240 if (mid
!= nritems
&&
4241 leaf_space_used(l
, mid
, nritems
- mid
) +
4242 data_size
> BTRFS_LEAF_DATA_SIZE(root
)) {
4243 if (data_size
&& !tried_avoid_double
)
4244 goto push_for_double
;
4250 if (leaf_space_used(l
, 0, mid
) + data_size
>
4251 BTRFS_LEAF_DATA_SIZE(root
)) {
4252 if (!extend
&& data_size
&& slot
== 0) {
4254 } else if ((extend
|| !data_size
) && slot
== 0) {
4258 if (mid
!= nritems
&&
4259 leaf_space_used(l
, mid
, nritems
- mid
) +
4260 data_size
> BTRFS_LEAF_DATA_SIZE(root
)) {
4261 if (data_size
&& !tried_avoid_double
)
4262 goto push_for_double
;
4270 btrfs_cpu_key_to_disk(&disk_key
, ins_key
);
4272 btrfs_item_key(l
, &disk_key
, mid
);
4274 right
= btrfs_alloc_tree_block(trans
, root
, 0, root
->root_key
.objectid
,
4275 &disk_key
, 0, l
->start
, 0);
4277 return PTR_ERR(right
);
4279 root_add_used(root
, root
->nodesize
);
4281 memset_extent_buffer(right
, 0, 0, sizeof(struct btrfs_header
));
4282 btrfs_set_header_bytenr(right
, right
->start
);
4283 btrfs_set_header_generation(right
, trans
->transid
);
4284 btrfs_set_header_backref_rev(right
, BTRFS_MIXED_BACKREF_REV
);
4285 btrfs_set_header_owner(right
, root
->root_key
.objectid
);
4286 btrfs_set_header_level(right
, 0);
4287 write_extent_buffer(right
, root
->fs_info
->fsid
,
4288 btrfs_header_fsid(), BTRFS_FSID_SIZE
);
4290 write_extent_buffer(right
, root
->fs_info
->chunk_tree_uuid
,
4291 btrfs_header_chunk_tree_uuid(right
),
4296 btrfs_set_header_nritems(right
, 0);
4297 insert_ptr(trans
, root
, path
, &disk_key
, right
->start
,
4298 path
->slots
[1] + 1, 1);
4299 btrfs_tree_unlock(path
->nodes
[0]);
4300 free_extent_buffer(path
->nodes
[0]);
4301 path
->nodes
[0] = right
;
4303 path
->slots
[1] += 1;
4305 btrfs_set_header_nritems(right
, 0);
4306 insert_ptr(trans
, root
, path
, &disk_key
, right
->start
,
4308 btrfs_tree_unlock(path
->nodes
[0]);
4309 free_extent_buffer(path
->nodes
[0]);
4310 path
->nodes
[0] = right
;
4312 if (path
->slots
[1] == 0)
4313 fixup_low_keys(root
, path
, &disk_key
, 1);
4315 btrfs_mark_buffer_dirty(right
);
4319 copy_for_split(trans
, root
, path
, l
, right
, slot
, mid
, nritems
);
4322 BUG_ON(num_doubles
!= 0);
4330 push_for_double_split(trans
, root
, path
, data_size
);
4331 tried_avoid_double
= 1;
4332 if (btrfs_leaf_free_space(root
, path
->nodes
[0]) >= data_size
)
4337 static noinline
int setup_leaf_for_split(struct btrfs_trans_handle
*trans
,
4338 struct btrfs_root
*root
,
4339 struct btrfs_path
*path
, int ins_len
)
4341 struct btrfs_key key
;
4342 struct extent_buffer
*leaf
;
4343 struct btrfs_file_extent_item
*fi
;
4348 leaf
= path
->nodes
[0];
4349 btrfs_item_key_to_cpu(leaf
, &key
, path
->slots
[0]);
4351 BUG_ON(key
.type
!= BTRFS_EXTENT_DATA_KEY
&&
4352 key
.type
!= BTRFS_EXTENT_CSUM_KEY
);
4354 if (btrfs_leaf_free_space(root
, leaf
) >= ins_len
)
4357 item_size
= btrfs_item_size_nr(leaf
, path
->slots
[0]);
4358 if (key
.type
== BTRFS_EXTENT_DATA_KEY
) {
4359 fi
= btrfs_item_ptr(leaf
, path
->slots
[0],
4360 struct btrfs_file_extent_item
);
4361 extent_len
= btrfs_file_extent_num_bytes(leaf
, fi
);
4363 btrfs_release_path(path
);
4365 path
->keep_locks
= 1;
4366 path
->search_for_split
= 1;
4367 ret
= btrfs_search_slot(trans
, root
, &key
, path
, 0, 1);
4368 path
->search_for_split
= 0;
4373 leaf
= path
->nodes
[0];
4374 /* if our item isn't there or got smaller, return now */
4375 if (ret
> 0 || item_size
!= btrfs_item_size_nr(leaf
, path
->slots
[0]))
4378 /* the leaf has changed, it now has room. return now */
4379 if (btrfs_leaf_free_space(root
, path
->nodes
[0]) >= ins_len
)
4382 if (key
.type
== BTRFS_EXTENT_DATA_KEY
) {
4383 fi
= btrfs_item_ptr(leaf
, path
->slots
[0],
4384 struct btrfs_file_extent_item
);
4385 if (extent_len
!= btrfs_file_extent_num_bytes(leaf
, fi
))
4389 btrfs_set_path_blocking(path
);
4390 ret
= split_leaf(trans
, root
, &key
, path
, ins_len
, 1);
4394 path
->keep_locks
= 0;
4395 btrfs_unlock_up_safe(path
, 1);
4398 path
->keep_locks
= 0;
4402 static noinline
int split_item(struct btrfs_trans_handle
*trans
,
4403 struct btrfs_root
*root
,
4404 struct btrfs_path
*path
,
4405 struct btrfs_key
*new_key
,
4406 unsigned long split_offset
)
4408 struct extent_buffer
*leaf
;
4409 struct btrfs_item
*item
;
4410 struct btrfs_item
*new_item
;
4416 struct btrfs_disk_key disk_key
;
4418 leaf
= path
->nodes
[0];
4419 BUG_ON(btrfs_leaf_free_space(root
, leaf
) < sizeof(struct btrfs_item
));
4421 btrfs_set_path_blocking(path
);
4423 item
= btrfs_item_nr(path
->slots
[0]);
4424 orig_offset
= btrfs_item_offset(leaf
, item
);
4425 item_size
= btrfs_item_size(leaf
, item
);
4427 buf
= kmalloc(item_size
, GFP_NOFS
);
4431 read_extent_buffer(leaf
, buf
, btrfs_item_ptr_offset(leaf
,
4432 path
->slots
[0]), item_size
);
4434 slot
= path
->slots
[0] + 1;
4435 nritems
= btrfs_header_nritems(leaf
);
4436 if (slot
!= nritems
) {
4437 /* shift the items */
4438 memmove_extent_buffer(leaf
, btrfs_item_nr_offset(slot
+ 1),
4439 btrfs_item_nr_offset(slot
),
4440 (nritems
- slot
) * sizeof(struct btrfs_item
));
4443 btrfs_cpu_key_to_disk(&disk_key
, new_key
);
4444 btrfs_set_item_key(leaf
, &disk_key
, slot
);
4446 new_item
= btrfs_item_nr(slot
);
4448 btrfs_set_item_offset(leaf
, new_item
, orig_offset
);
4449 btrfs_set_item_size(leaf
, new_item
, item_size
- split_offset
);
4451 btrfs_set_item_offset(leaf
, item
,
4452 orig_offset
+ item_size
- split_offset
);
4453 btrfs_set_item_size(leaf
, item
, split_offset
);
4455 btrfs_set_header_nritems(leaf
, nritems
+ 1);
4457 /* write the data for the start of the original item */
4458 write_extent_buffer(leaf
, buf
,
4459 btrfs_item_ptr_offset(leaf
, path
->slots
[0]),
4462 /* write the data for the new item */
4463 write_extent_buffer(leaf
, buf
+ split_offset
,
4464 btrfs_item_ptr_offset(leaf
, slot
),
4465 item_size
- split_offset
);
4466 btrfs_mark_buffer_dirty(leaf
);
4468 BUG_ON(btrfs_leaf_free_space(root
, leaf
) < 0);
4474 * This function splits a single item into two items,
4475 * giving 'new_key' to the new item and splitting the
4476 * old one at split_offset (from the start of the item).
4478 * The path may be released by this operation. After
4479 * the split, the path is pointing to the old item. The
4480 * new item is going to be in the same node as the old one.
4482 * Note, the item being split must be smaller enough to live alone on
4483 * a tree block with room for one extra struct btrfs_item
4485 * This allows us to split the item in place, keeping a lock on the
4486 * leaf the entire time.
4488 int btrfs_split_item(struct btrfs_trans_handle
*trans
,
4489 struct btrfs_root
*root
,
4490 struct btrfs_path
*path
,
4491 struct btrfs_key
*new_key
,
4492 unsigned long split_offset
)
4495 ret
= setup_leaf_for_split(trans
, root
, path
,
4496 sizeof(struct btrfs_item
));
4500 ret
= split_item(trans
, root
, path
, new_key
, split_offset
);
4505 * This function duplicate a item, giving 'new_key' to the new item.
4506 * It guarantees both items live in the same tree leaf and the new item
4507 * is contiguous with the original item.
4509 * This allows us to split file extent in place, keeping a lock on the
4510 * leaf the entire time.
4512 int btrfs_duplicate_item(struct btrfs_trans_handle
*trans
,
4513 struct btrfs_root
*root
,
4514 struct btrfs_path
*path
,
4515 struct btrfs_key
*new_key
)
4517 struct extent_buffer
*leaf
;
4521 leaf
= path
->nodes
[0];
4522 item_size
= btrfs_item_size_nr(leaf
, path
->slots
[0]);
4523 ret
= setup_leaf_for_split(trans
, root
, path
,
4524 item_size
+ sizeof(struct btrfs_item
));
4529 setup_items_for_insert(root
, path
, new_key
, &item_size
,
4530 item_size
, item_size
+
4531 sizeof(struct btrfs_item
), 1);
4532 leaf
= path
->nodes
[0];
4533 memcpy_extent_buffer(leaf
,
4534 btrfs_item_ptr_offset(leaf
, path
->slots
[0]),
4535 btrfs_item_ptr_offset(leaf
, path
->slots
[0] - 1),
4541 * make the item pointed to by the path smaller. new_size indicates
4542 * how small to make it, and from_end tells us if we just chop bytes
4543 * off the end of the item or if we shift the item to chop bytes off
4546 void btrfs_truncate_item(struct btrfs_root
*root
, struct btrfs_path
*path
,
4547 u32 new_size
, int from_end
)
4550 struct extent_buffer
*leaf
;
4551 struct btrfs_item
*item
;
4553 unsigned int data_end
;
4554 unsigned int old_data_start
;
4555 unsigned int old_size
;
4556 unsigned int size_diff
;
4558 struct btrfs_map_token token
;
4560 btrfs_init_map_token(&token
);
4562 leaf
= path
->nodes
[0];
4563 slot
= path
->slots
[0];
4565 old_size
= btrfs_item_size_nr(leaf
, slot
);
4566 if (old_size
== new_size
)
4569 nritems
= btrfs_header_nritems(leaf
);
4570 data_end
= leaf_data_end(root
, leaf
);
4572 old_data_start
= btrfs_item_offset_nr(leaf
, slot
);
4574 size_diff
= old_size
- new_size
;
4577 BUG_ON(slot
>= nritems
);
4580 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4582 /* first correct the data pointers */
4583 for (i
= slot
; i
< nritems
; i
++) {
4585 item
= btrfs_item_nr(i
);
4587 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4588 btrfs_set_token_item_offset(leaf
, item
,
4589 ioff
+ size_diff
, &token
);
4592 /* shift the data */
4594 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4595 data_end
+ size_diff
, btrfs_leaf_data(leaf
) +
4596 data_end
, old_data_start
+ new_size
- data_end
);
4598 struct btrfs_disk_key disk_key
;
4601 btrfs_item_key(leaf
, &disk_key
, slot
);
4603 if (btrfs_disk_key_type(&disk_key
) == BTRFS_EXTENT_DATA_KEY
) {
4605 struct btrfs_file_extent_item
*fi
;
4607 fi
= btrfs_item_ptr(leaf
, slot
,
4608 struct btrfs_file_extent_item
);
4609 fi
= (struct btrfs_file_extent_item
*)(
4610 (unsigned long)fi
- size_diff
);
4612 if (btrfs_file_extent_type(leaf
, fi
) ==
4613 BTRFS_FILE_EXTENT_INLINE
) {
4614 ptr
= btrfs_item_ptr_offset(leaf
, slot
);
4615 memmove_extent_buffer(leaf
, ptr
,
4617 BTRFS_FILE_EXTENT_INLINE_DATA_START
);
4621 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4622 data_end
+ size_diff
, btrfs_leaf_data(leaf
) +
4623 data_end
, old_data_start
- data_end
);
4625 offset
= btrfs_disk_key_offset(&disk_key
);
4626 btrfs_set_disk_key_offset(&disk_key
, offset
+ size_diff
);
4627 btrfs_set_item_key(leaf
, &disk_key
, slot
);
4629 fixup_low_keys(root
, path
, &disk_key
, 1);
4632 item
= btrfs_item_nr(slot
);
4633 btrfs_set_item_size(leaf
, item
, new_size
);
4634 btrfs_mark_buffer_dirty(leaf
);
4636 if (btrfs_leaf_free_space(root
, leaf
) < 0) {
4637 btrfs_print_leaf(root
, leaf
);
4643 * make the item pointed to by the path bigger, data_size is the added size.
4645 void btrfs_extend_item(struct btrfs_root
*root
, struct btrfs_path
*path
,
4649 struct extent_buffer
*leaf
;
4650 struct btrfs_item
*item
;
4652 unsigned int data_end
;
4653 unsigned int old_data
;
4654 unsigned int old_size
;
4656 struct btrfs_map_token token
;
4658 btrfs_init_map_token(&token
);
4660 leaf
= path
->nodes
[0];
4662 nritems
= btrfs_header_nritems(leaf
);
4663 data_end
= leaf_data_end(root
, leaf
);
4665 if (btrfs_leaf_free_space(root
, leaf
) < data_size
) {
4666 btrfs_print_leaf(root
, leaf
);
4669 slot
= path
->slots
[0];
4670 old_data
= btrfs_item_end_nr(leaf
, slot
);
4673 if (slot
>= nritems
) {
4674 btrfs_print_leaf(root
, leaf
);
4675 btrfs_crit(root
->fs_info
, "slot %d too large, nritems %d",
4681 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4683 /* first correct the data pointers */
4684 for (i
= slot
; i
< nritems
; i
++) {
4686 item
= btrfs_item_nr(i
);
4688 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4689 btrfs_set_token_item_offset(leaf
, item
,
4690 ioff
- data_size
, &token
);
4693 /* shift the data */
4694 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4695 data_end
- data_size
, btrfs_leaf_data(leaf
) +
4696 data_end
, old_data
- data_end
);
4698 data_end
= old_data
;
4699 old_size
= btrfs_item_size_nr(leaf
, slot
);
4700 item
= btrfs_item_nr(slot
);
4701 btrfs_set_item_size(leaf
, item
, old_size
+ data_size
);
4702 btrfs_mark_buffer_dirty(leaf
);
4704 if (btrfs_leaf_free_space(root
, leaf
) < 0) {
4705 btrfs_print_leaf(root
, leaf
);
4711 * this is a helper for btrfs_insert_empty_items, the main goal here is
4712 * to save stack depth by doing the bulk of the work in a function
4713 * that doesn't call btrfs_search_slot
4715 void setup_items_for_insert(struct btrfs_root
*root
, struct btrfs_path
*path
,
4716 struct btrfs_key
*cpu_key
, u32
*data_size
,
4717 u32 total_data
, u32 total_size
, int nr
)
4719 struct btrfs_item
*item
;
4722 unsigned int data_end
;
4723 struct btrfs_disk_key disk_key
;
4724 struct extent_buffer
*leaf
;
4726 struct btrfs_map_token token
;
4728 if (path
->slots
[0] == 0) {
4729 btrfs_cpu_key_to_disk(&disk_key
, cpu_key
);
4730 fixup_low_keys(root
, path
, &disk_key
, 1);
4732 btrfs_unlock_up_safe(path
, 1);
4734 btrfs_init_map_token(&token
);
4736 leaf
= path
->nodes
[0];
4737 slot
= path
->slots
[0];
4739 nritems
= btrfs_header_nritems(leaf
);
4740 data_end
= leaf_data_end(root
, leaf
);
4742 if (btrfs_leaf_free_space(root
, leaf
) < total_size
) {
4743 btrfs_print_leaf(root
, leaf
);
4744 btrfs_crit(root
->fs_info
, "not enough freespace need %u have %d",
4745 total_size
, btrfs_leaf_free_space(root
, leaf
));
4749 if (slot
!= nritems
) {
4750 unsigned int old_data
= btrfs_item_end_nr(leaf
, slot
);
4752 if (old_data
< data_end
) {
4753 btrfs_print_leaf(root
, leaf
);
4754 btrfs_crit(root
->fs_info
, "slot %d old_data %d data_end %d",
4755 slot
, old_data
, data_end
);
4759 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4761 /* first correct the data pointers */
4762 for (i
= slot
; i
< nritems
; i
++) {
4765 item
= btrfs_item_nr( i
);
4766 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4767 btrfs_set_token_item_offset(leaf
, item
,
4768 ioff
- total_data
, &token
);
4770 /* shift the items */
4771 memmove_extent_buffer(leaf
, btrfs_item_nr_offset(slot
+ nr
),
4772 btrfs_item_nr_offset(slot
),
4773 (nritems
- slot
) * sizeof(struct btrfs_item
));
4775 /* shift the data */
4776 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4777 data_end
- total_data
, btrfs_leaf_data(leaf
) +
4778 data_end
, old_data
- data_end
);
4779 data_end
= old_data
;
4782 /* setup the item for the new data */
4783 for (i
= 0; i
< nr
; i
++) {
4784 btrfs_cpu_key_to_disk(&disk_key
, cpu_key
+ i
);
4785 btrfs_set_item_key(leaf
, &disk_key
, slot
+ i
);
4786 item
= btrfs_item_nr(slot
+ i
);
4787 btrfs_set_token_item_offset(leaf
, item
,
4788 data_end
- data_size
[i
], &token
);
4789 data_end
-= data_size
[i
];
4790 btrfs_set_token_item_size(leaf
, item
, data_size
[i
], &token
);
4793 btrfs_set_header_nritems(leaf
, nritems
+ nr
);
4794 btrfs_mark_buffer_dirty(leaf
);
4796 if (btrfs_leaf_free_space(root
, leaf
) < 0) {
4797 btrfs_print_leaf(root
, leaf
);
4803 * Given a key and some data, insert items into the tree.
4804 * This does all the path init required, making room in the tree if needed.
4806 int btrfs_insert_empty_items(struct btrfs_trans_handle
*trans
,
4807 struct btrfs_root
*root
,
4808 struct btrfs_path
*path
,
4809 struct btrfs_key
*cpu_key
, u32
*data_size
,
4818 for (i
= 0; i
< nr
; i
++)
4819 total_data
+= data_size
[i
];
4821 total_size
= total_data
+ (nr
* sizeof(struct btrfs_item
));
4822 ret
= btrfs_search_slot(trans
, root
, cpu_key
, path
, total_size
, 1);
4828 slot
= path
->slots
[0];
4831 setup_items_for_insert(root
, path
, cpu_key
, data_size
,
4832 total_data
, total_size
, nr
);
4837 * Given a key and some data, insert an item into the tree.
4838 * This does all the path init required, making room in the tree if needed.
4840 int btrfs_insert_item(struct btrfs_trans_handle
*trans
, struct btrfs_root
4841 *root
, struct btrfs_key
*cpu_key
, void *data
, u32
4845 struct btrfs_path
*path
;
4846 struct extent_buffer
*leaf
;
4849 path
= btrfs_alloc_path();
4852 ret
= btrfs_insert_empty_item(trans
, root
, path
, cpu_key
, data_size
);
4854 leaf
= path
->nodes
[0];
4855 ptr
= btrfs_item_ptr_offset(leaf
, path
->slots
[0]);
4856 write_extent_buffer(leaf
, data
, ptr
, data_size
);
4857 btrfs_mark_buffer_dirty(leaf
);
4859 btrfs_free_path(path
);
4864 * delete the pointer from a given node.
4866 * the tree should have been previously balanced so the deletion does not
4869 static void del_ptr(struct btrfs_root
*root
, struct btrfs_path
*path
,
4870 int level
, int slot
)
4872 struct extent_buffer
*parent
= path
->nodes
[level
];
4876 nritems
= btrfs_header_nritems(parent
);
4877 if (slot
!= nritems
- 1) {
4879 tree_mod_log_eb_move(root
->fs_info
, parent
, slot
,
4880 slot
+ 1, nritems
- slot
- 1);
4881 memmove_extent_buffer(parent
,
4882 btrfs_node_key_ptr_offset(slot
),
4883 btrfs_node_key_ptr_offset(slot
+ 1),
4884 sizeof(struct btrfs_key_ptr
) *
4885 (nritems
- slot
- 1));
4887 ret
= tree_mod_log_insert_key(root
->fs_info
, parent
, slot
,
4888 MOD_LOG_KEY_REMOVE
, GFP_NOFS
);
4893 btrfs_set_header_nritems(parent
, nritems
);
4894 if (nritems
== 0 && parent
== root
->node
) {
4895 BUG_ON(btrfs_header_level(root
->node
) != 1);
4896 /* just turn the root into a leaf and break */
4897 btrfs_set_header_level(root
->node
, 0);
4898 } else if (slot
== 0) {
4899 struct btrfs_disk_key disk_key
;
4901 btrfs_node_key(parent
, &disk_key
, 0);
4902 fixup_low_keys(root
, path
, &disk_key
, level
+ 1);
4904 btrfs_mark_buffer_dirty(parent
);
4908 * a helper function to delete the leaf pointed to by path->slots[1] and
4911 * This deletes the pointer in path->nodes[1] and frees the leaf
4912 * block extent. zero is returned if it all worked out, < 0 otherwise.
4914 * The path must have already been setup for deleting the leaf, including
4915 * all the proper balancing. path->nodes[1] must be locked.
4917 static noinline
void btrfs_del_leaf(struct btrfs_trans_handle
*trans
,
4918 struct btrfs_root
*root
,
4919 struct btrfs_path
*path
,
4920 struct extent_buffer
*leaf
)
4922 WARN_ON(btrfs_header_generation(leaf
) != trans
->transid
);
4923 del_ptr(root
, path
, 1, path
->slots
[1]);
4926 * btrfs_free_extent is expensive, we want to make sure we
4927 * aren't holding any locks when we call it
4929 btrfs_unlock_up_safe(path
, 0);
4931 root_sub_used(root
, leaf
->len
);
4933 extent_buffer_get(leaf
);
4934 btrfs_free_tree_block(trans
, root
, leaf
, 0, 1);
4935 free_extent_buffer_stale(leaf
);
4938 * delete the item at the leaf level in path. If that empties
4939 * the leaf, remove it from the tree
4941 int btrfs_del_items(struct btrfs_trans_handle
*trans
, struct btrfs_root
*root
,
4942 struct btrfs_path
*path
, int slot
, int nr
)
4944 struct extent_buffer
*leaf
;
4945 struct btrfs_item
*item
;
4952 struct btrfs_map_token token
;
4954 btrfs_init_map_token(&token
);
4956 leaf
= path
->nodes
[0];
4957 last_off
= btrfs_item_offset_nr(leaf
, slot
+ nr
- 1);
4959 for (i
= 0; i
< nr
; i
++)
4960 dsize
+= btrfs_item_size_nr(leaf
, slot
+ i
);
4962 nritems
= btrfs_header_nritems(leaf
);
4964 if (slot
+ nr
!= nritems
) {
4965 int data_end
= leaf_data_end(root
, leaf
);
4967 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4969 btrfs_leaf_data(leaf
) + data_end
,
4970 last_off
- data_end
);
4972 for (i
= slot
+ nr
; i
< nritems
; i
++) {
4975 item
= btrfs_item_nr(i
);
4976 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4977 btrfs_set_token_item_offset(leaf
, item
,
4978 ioff
+ dsize
, &token
);
4981 memmove_extent_buffer(leaf
, btrfs_item_nr_offset(slot
),
4982 btrfs_item_nr_offset(slot
+ nr
),
4983 sizeof(struct btrfs_item
) *
4984 (nritems
- slot
- nr
));
4986 btrfs_set_header_nritems(leaf
, nritems
- nr
);
4989 /* delete the leaf if we've emptied it */
4991 if (leaf
== root
->node
) {
4992 btrfs_set_header_level(leaf
, 0);
4994 btrfs_set_path_blocking(path
);
4995 clean_tree_block(trans
, root
, leaf
);
4996 btrfs_del_leaf(trans
, root
, path
, leaf
);
4999 int used
= leaf_space_used(leaf
, 0, nritems
);
5001 struct btrfs_disk_key disk_key
;
5003 btrfs_item_key(leaf
, &disk_key
, 0);
5004 fixup_low_keys(root
, path
, &disk_key
, 1);
5007 /* delete the leaf if it is mostly empty */
5008 if (used
< BTRFS_LEAF_DATA_SIZE(root
) / 3) {
5009 /* push_leaf_left fixes the path.
5010 * make sure the path still points to our leaf
5011 * for possible call to del_ptr below
5013 slot
= path
->slots
[1];
5014 extent_buffer_get(leaf
);
5016 btrfs_set_path_blocking(path
);
5017 wret
= push_leaf_left(trans
, root
, path
, 1, 1,
5019 if (wret
< 0 && wret
!= -ENOSPC
)
5022 if (path
->nodes
[0] == leaf
&&
5023 btrfs_header_nritems(leaf
)) {
5024 wret
= push_leaf_right(trans
, root
, path
, 1,
5026 if (wret
< 0 && wret
!= -ENOSPC
)
5030 if (btrfs_header_nritems(leaf
) == 0) {
5031 path
->slots
[1] = slot
;
5032 btrfs_del_leaf(trans
, root
, path
, leaf
);
5033 free_extent_buffer(leaf
);
5036 /* if we're still in the path, make sure
5037 * we're dirty. Otherwise, one of the
5038 * push_leaf functions must have already
5039 * dirtied this buffer
5041 if (path
->nodes
[0] == leaf
)
5042 btrfs_mark_buffer_dirty(leaf
);
5043 free_extent_buffer(leaf
);
5046 btrfs_mark_buffer_dirty(leaf
);
5053 * search the tree again to find a leaf with lesser keys
5054 * returns 0 if it found something or 1 if there are no lesser leaves.
5055 * returns < 0 on io errors.
5057 * This may release the path, and so you may lose any locks held at the
5060 int btrfs_prev_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
)
5062 struct btrfs_key key
;
5063 struct btrfs_disk_key found_key
;
5066 btrfs_item_key_to_cpu(path
->nodes
[0], &key
, 0);
5068 if (key
.offset
> 0) {
5070 } else if (key
.type
> 0) {
5072 key
.offset
= (u64
)-1;
5073 } else if (key
.objectid
> 0) {
5076 key
.offset
= (u64
)-1;
5081 btrfs_release_path(path
);
5082 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
5085 btrfs_item_key(path
->nodes
[0], &found_key
, 0);
5086 ret
= comp_keys(&found_key
, &key
);
5088 * We might have had an item with the previous key in the tree right
5089 * before we released our path. And after we released our path, that
5090 * item might have been pushed to the first slot (0) of the leaf we
5091 * were holding due to a tree balance. Alternatively, an item with the
5092 * previous key can exist as the only element of a leaf (big fat item).
5093 * Therefore account for these 2 cases, so that our callers (like
5094 * btrfs_previous_item) don't miss an existing item with a key matching
5095 * the previous key we computed above.
5103 * A helper function to walk down the tree starting at min_key, and looking
5104 * for nodes or leaves that are have a minimum transaction id.
5105 * This is used by the btree defrag code, and tree logging
5107 * This does not cow, but it does stuff the starting key it finds back
5108 * into min_key, so you can call btrfs_search_slot with cow=1 on the
5109 * key and get a writable path.
5111 * This does lock as it descends, and path->keep_locks should be set
5112 * to 1 by the caller.
5114 * This honors path->lowest_level to prevent descent past a given level
5117 * min_trans indicates the oldest transaction that you are interested
5118 * in walking through. Any nodes or leaves older than min_trans are
5119 * skipped over (without reading them).
5121 * returns zero if something useful was found, < 0 on error and 1 if there
5122 * was nothing in the tree that matched the search criteria.
5124 int btrfs_search_forward(struct btrfs_root
*root
, struct btrfs_key
*min_key
,
5125 struct btrfs_path
*path
,
5128 struct extent_buffer
*cur
;
5129 struct btrfs_key found_key
;
5135 int keep_locks
= path
->keep_locks
;
5137 path
->keep_locks
= 1;
5139 cur
= btrfs_read_lock_root_node(root
);
5140 level
= btrfs_header_level(cur
);
5141 WARN_ON(path
->nodes
[level
]);
5142 path
->nodes
[level
] = cur
;
5143 path
->locks
[level
] = BTRFS_READ_LOCK
;
5145 if (btrfs_header_generation(cur
) < min_trans
) {
5150 nritems
= btrfs_header_nritems(cur
);
5151 level
= btrfs_header_level(cur
);
5152 sret
= bin_search(cur
, min_key
, level
, &slot
);
5154 /* at the lowest level, we're done, setup the path and exit */
5155 if (level
== path
->lowest_level
) {
5156 if (slot
>= nritems
)
5159 path
->slots
[level
] = slot
;
5160 btrfs_item_key_to_cpu(cur
, &found_key
, slot
);
5163 if (sret
&& slot
> 0)
5166 * check this node pointer against the min_trans parameters.
5167 * If it is too old, old, skip to the next one.
5169 while (slot
< nritems
) {
5172 gen
= btrfs_node_ptr_generation(cur
, slot
);
5173 if (gen
< min_trans
) {
5181 * we didn't find a candidate key in this node, walk forward
5182 * and find another one
5184 if (slot
>= nritems
) {
5185 path
->slots
[level
] = slot
;
5186 btrfs_set_path_blocking(path
);
5187 sret
= btrfs_find_next_key(root
, path
, min_key
, level
,
5190 btrfs_release_path(path
);
5196 /* save our key for returning back */
5197 btrfs_node_key_to_cpu(cur
, &found_key
, slot
);
5198 path
->slots
[level
] = slot
;
5199 if (level
== path
->lowest_level
) {
5203 btrfs_set_path_blocking(path
);
5204 cur
= read_node_slot(root
, cur
, slot
);
5205 BUG_ON(!cur
); /* -ENOMEM */
5207 btrfs_tree_read_lock(cur
);
5209 path
->locks
[level
- 1] = BTRFS_READ_LOCK
;
5210 path
->nodes
[level
- 1] = cur
;
5211 unlock_up(path
, level
, 1, 0, NULL
);
5212 btrfs_clear_path_blocking(path
, NULL
, 0);
5215 path
->keep_locks
= keep_locks
;
5217 btrfs_unlock_up_safe(path
, path
->lowest_level
+ 1);
5218 btrfs_set_path_blocking(path
);
5219 memcpy(min_key
, &found_key
, sizeof(found_key
));
5224 static void tree_move_down(struct btrfs_root
*root
,
5225 struct btrfs_path
*path
,
5226 int *level
, int root_level
)
5228 BUG_ON(*level
== 0);
5229 path
->nodes
[*level
- 1] = read_node_slot(root
, path
->nodes
[*level
],
5230 path
->slots
[*level
]);
5231 path
->slots
[*level
- 1] = 0;
5235 static int tree_move_next_or_upnext(struct btrfs_root
*root
,
5236 struct btrfs_path
*path
,
5237 int *level
, int root_level
)
5241 nritems
= btrfs_header_nritems(path
->nodes
[*level
]);
5243 path
->slots
[*level
]++;
5245 while (path
->slots
[*level
] >= nritems
) {
5246 if (*level
== root_level
)
5250 path
->slots
[*level
] = 0;
5251 free_extent_buffer(path
->nodes
[*level
]);
5252 path
->nodes
[*level
] = NULL
;
5254 path
->slots
[*level
]++;
5256 nritems
= btrfs_header_nritems(path
->nodes
[*level
]);
5263 * Returns 1 if it had to move up and next. 0 is returned if it moved only next
5266 static int tree_advance(struct btrfs_root
*root
,
5267 struct btrfs_path
*path
,
5268 int *level
, int root_level
,
5270 struct btrfs_key
*key
)
5274 if (*level
== 0 || !allow_down
) {
5275 ret
= tree_move_next_or_upnext(root
, path
, level
, root_level
);
5277 tree_move_down(root
, path
, level
, root_level
);
5282 btrfs_item_key_to_cpu(path
->nodes
[*level
], key
,
5283 path
->slots
[*level
]);
5285 btrfs_node_key_to_cpu(path
->nodes
[*level
], key
,
5286 path
->slots
[*level
]);
5291 static int tree_compare_item(struct btrfs_root
*left_root
,
5292 struct btrfs_path
*left_path
,
5293 struct btrfs_path
*right_path
,
5298 unsigned long off1
, off2
;
5300 len1
= btrfs_item_size_nr(left_path
->nodes
[0], left_path
->slots
[0]);
5301 len2
= btrfs_item_size_nr(right_path
->nodes
[0], right_path
->slots
[0]);
5305 off1
= btrfs_item_ptr_offset(left_path
->nodes
[0], left_path
->slots
[0]);
5306 off2
= btrfs_item_ptr_offset(right_path
->nodes
[0],
5307 right_path
->slots
[0]);
5309 read_extent_buffer(left_path
->nodes
[0], tmp_buf
, off1
, len1
);
5311 cmp
= memcmp_extent_buffer(right_path
->nodes
[0], tmp_buf
, off2
, len1
);
5318 #define ADVANCE_ONLY_NEXT -1
5321 * This function compares two trees and calls the provided callback for
5322 * every changed/new/deleted item it finds.
5323 * If shared tree blocks are encountered, whole subtrees are skipped, making
5324 * the compare pretty fast on snapshotted subvolumes.
5326 * This currently works on commit roots only. As commit roots are read only,
5327 * we don't do any locking. The commit roots are protected with transactions.
5328 * Transactions are ended and rejoined when a commit is tried in between.
5330 * This function checks for modifications done to the trees while comparing.
5331 * If it detects a change, it aborts immediately.
5333 int btrfs_compare_trees(struct btrfs_root
*left_root
,
5334 struct btrfs_root
*right_root
,
5335 btrfs_changed_cb_t changed_cb
, void *ctx
)
5339 struct btrfs_path
*left_path
= NULL
;
5340 struct btrfs_path
*right_path
= NULL
;
5341 struct btrfs_key left_key
;
5342 struct btrfs_key right_key
;
5343 char *tmp_buf
= NULL
;
5344 int left_root_level
;
5345 int right_root_level
;
5348 int left_end_reached
;
5349 int right_end_reached
;
5357 left_path
= btrfs_alloc_path();
5362 right_path
= btrfs_alloc_path();
5368 tmp_buf
= kmalloc(left_root
->nodesize
, GFP_NOFS
);
5374 left_path
->search_commit_root
= 1;
5375 left_path
->skip_locking
= 1;
5376 right_path
->search_commit_root
= 1;
5377 right_path
->skip_locking
= 1;
5380 * Strategy: Go to the first items of both trees. Then do
5382 * If both trees are at level 0
5383 * Compare keys of current items
5384 * If left < right treat left item as new, advance left tree
5386 * If left > right treat right item as deleted, advance right tree
5388 * If left == right do deep compare of items, treat as changed if
5389 * needed, advance both trees and repeat
5390 * If both trees are at the same level but not at level 0
5391 * Compare keys of current nodes/leafs
5392 * If left < right advance left tree and repeat
5393 * If left > right advance right tree and repeat
5394 * If left == right compare blockptrs of the next nodes/leafs
5395 * If they match advance both trees but stay at the same level
5397 * If they don't match advance both trees while allowing to go
5399 * If tree levels are different
5400 * Advance the tree that needs it and repeat
5402 * Advancing a tree means:
5403 * If we are at level 0, try to go to the next slot. If that's not
5404 * possible, go one level up and repeat. Stop when we found a level
5405 * where we could go to the next slot. We may at this point be on a
5408 * If we are not at level 0 and not on shared tree blocks, go one
5411 * If we are not at level 0 and on shared tree blocks, go one slot to
5412 * the right if possible or go up and right.
5415 down_read(&left_root
->fs_info
->commit_root_sem
);
5416 left_level
= btrfs_header_level(left_root
->commit_root
);
5417 left_root_level
= left_level
;
5418 left_path
->nodes
[left_level
] = left_root
->commit_root
;
5419 extent_buffer_get(left_path
->nodes
[left_level
]);
5421 right_level
= btrfs_header_level(right_root
->commit_root
);
5422 right_root_level
= right_level
;
5423 right_path
->nodes
[right_level
] = right_root
->commit_root
;
5424 extent_buffer_get(right_path
->nodes
[right_level
]);
5425 up_read(&left_root
->fs_info
->commit_root_sem
);
5427 if (left_level
== 0)
5428 btrfs_item_key_to_cpu(left_path
->nodes
[left_level
],
5429 &left_key
, left_path
->slots
[left_level
]);
5431 btrfs_node_key_to_cpu(left_path
->nodes
[left_level
],
5432 &left_key
, left_path
->slots
[left_level
]);
5433 if (right_level
== 0)
5434 btrfs_item_key_to_cpu(right_path
->nodes
[right_level
],
5435 &right_key
, right_path
->slots
[right_level
]);
5437 btrfs_node_key_to_cpu(right_path
->nodes
[right_level
],
5438 &right_key
, right_path
->slots
[right_level
]);
5440 left_end_reached
= right_end_reached
= 0;
5441 advance_left
= advance_right
= 0;
5444 if (advance_left
&& !left_end_reached
) {
5445 ret
= tree_advance(left_root
, left_path
, &left_level
,
5447 advance_left
!= ADVANCE_ONLY_NEXT
,
5450 left_end_reached
= ADVANCE
;
5453 if (advance_right
&& !right_end_reached
) {
5454 ret
= tree_advance(right_root
, right_path
, &right_level
,
5456 advance_right
!= ADVANCE_ONLY_NEXT
,
5459 right_end_reached
= ADVANCE
;
5463 if (left_end_reached
&& right_end_reached
) {
5466 } else if (left_end_reached
) {
5467 if (right_level
== 0) {
5468 ret
= changed_cb(left_root
, right_root
,
5469 left_path
, right_path
,
5471 BTRFS_COMPARE_TREE_DELETED
,
5476 advance_right
= ADVANCE
;
5478 } else if (right_end_reached
) {
5479 if (left_level
== 0) {
5480 ret
= changed_cb(left_root
, right_root
,
5481 left_path
, right_path
,
5483 BTRFS_COMPARE_TREE_NEW
,
5488 advance_left
= ADVANCE
;
5492 if (left_level
== 0 && right_level
== 0) {
5493 cmp
= btrfs_comp_cpu_keys(&left_key
, &right_key
);
5495 ret
= changed_cb(left_root
, right_root
,
5496 left_path
, right_path
,
5498 BTRFS_COMPARE_TREE_NEW
,
5502 advance_left
= ADVANCE
;
5503 } else if (cmp
> 0) {
5504 ret
= changed_cb(left_root
, right_root
,
5505 left_path
, right_path
,
5507 BTRFS_COMPARE_TREE_DELETED
,
5511 advance_right
= ADVANCE
;
5513 enum btrfs_compare_tree_result result
;
5515 WARN_ON(!extent_buffer_uptodate(left_path
->nodes
[0]));
5516 ret
= tree_compare_item(left_root
, left_path
,
5517 right_path
, tmp_buf
);
5519 result
= BTRFS_COMPARE_TREE_CHANGED
;
5521 result
= BTRFS_COMPARE_TREE_SAME
;
5522 ret
= changed_cb(left_root
, right_root
,
5523 left_path
, right_path
,
5524 &left_key
, result
, ctx
);
5527 advance_left
= ADVANCE
;
5528 advance_right
= ADVANCE
;
5530 } else if (left_level
== right_level
) {
5531 cmp
= btrfs_comp_cpu_keys(&left_key
, &right_key
);
5533 advance_left
= ADVANCE
;
5534 } else if (cmp
> 0) {
5535 advance_right
= ADVANCE
;
5537 left_blockptr
= btrfs_node_blockptr(
5538 left_path
->nodes
[left_level
],
5539 left_path
->slots
[left_level
]);
5540 right_blockptr
= btrfs_node_blockptr(
5541 right_path
->nodes
[right_level
],
5542 right_path
->slots
[right_level
]);
5543 left_gen
= btrfs_node_ptr_generation(
5544 left_path
->nodes
[left_level
],
5545 left_path
->slots
[left_level
]);
5546 right_gen
= btrfs_node_ptr_generation(
5547 right_path
->nodes
[right_level
],
5548 right_path
->slots
[right_level
]);
5549 if (left_blockptr
== right_blockptr
&&
5550 left_gen
== right_gen
) {
5552 * As we're on a shared block, don't
5553 * allow to go deeper.
5555 advance_left
= ADVANCE_ONLY_NEXT
;
5556 advance_right
= ADVANCE_ONLY_NEXT
;
5558 advance_left
= ADVANCE
;
5559 advance_right
= ADVANCE
;
5562 } else if (left_level
< right_level
) {
5563 advance_right
= ADVANCE
;
5565 advance_left
= ADVANCE
;
5570 btrfs_free_path(left_path
);
5571 btrfs_free_path(right_path
);
5577 * this is similar to btrfs_next_leaf, but does not try to preserve
5578 * and fixup the path. It looks for and returns the next key in the
5579 * tree based on the current path and the min_trans parameters.
5581 * 0 is returned if another key is found, < 0 if there are any errors
5582 * and 1 is returned if there are no higher keys in the tree
5584 * path->keep_locks should be set to 1 on the search made before
5585 * calling this function.
5587 int btrfs_find_next_key(struct btrfs_root
*root
, struct btrfs_path
*path
,
5588 struct btrfs_key
*key
, int level
, u64 min_trans
)
5591 struct extent_buffer
*c
;
5593 WARN_ON(!path
->keep_locks
);
5594 while (level
< BTRFS_MAX_LEVEL
) {
5595 if (!path
->nodes
[level
])
5598 slot
= path
->slots
[level
] + 1;
5599 c
= path
->nodes
[level
];
5601 if (slot
>= btrfs_header_nritems(c
)) {
5604 struct btrfs_key cur_key
;
5605 if (level
+ 1 >= BTRFS_MAX_LEVEL
||
5606 !path
->nodes
[level
+ 1])
5609 if (path
->locks
[level
+ 1]) {
5614 slot
= btrfs_header_nritems(c
) - 1;
5616 btrfs_item_key_to_cpu(c
, &cur_key
, slot
);
5618 btrfs_node_key_to_cpu(c
, &cur_key
, slot
);
5620 orig_lowest
= path
->lowest_level
;
5621 btrfs_release_path(path
);
5622 path
->lowest_level
= level
;
5623 ret
= btrfs_search_slot(NULL
, root
, &cur_key
, path
,
5625 path
->lowest_level
= orig_lowest
;
5629 c
= path
->nodes
[level
];
5630 slot
= path
->slots
[level
];
5637 btrfs_item_key_to_cpu(c
, key
, slot
);
5639 u64 gen
= btrfs_node_ptr_generation(c
, slot
);
5641 if (gen
< min_trans
) {
5645 btrfs_node_key_to_cpu(c
, key
, slot
);
5653 * search the tree again to find a leaf with greater keys
5654 * returns 0 if it found something or 1 if there are no greater leaves.
5655 * returns < 0 on io errors.
5657 int btrfs_next_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
)
5659 return btrfs_next_old_leaf(root
, path
, 0);
5662 int btrfs_next_old_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
,
5667 struct extent_buffer
*c
;
5668 struct extent_buffer
*next
;
5669 struct btrfs_key key
;
5672 int old_spinning
= path
->leave_spinning
;
5673 int next_rw_lock
= 0;
5675 nritems
= btrfs_header_nritems(path
->nodes
[0]);
5679 btrfs_item_key_to_cpu(path
->nodes
[0], &key
, nritems
- 1);
5684 btrfs_release_path(path
);
5686 path
->keep_locks
= 1;
5687 path
->leave_spinning
= 1;
5690 ret
= btrfs_search_old_slot(root
, &key
, path
, time_seq
);
5692 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
5693 path
->keep_locks
= 0;
5698 nritems
= btrfs_header_nritems(path
->nodes
[0]);
5700 * by releasing the path above we dropped all our locks. A balance
5701 * could have added more items next to the key that used to be
5702 * at the very end of the block. So, check again here and
5703 * advance the path if there are now more items available.
5705 if (nritems
> 0 && path
->slots
[0] < nritems
- 1) {
5712 * So the above check misses one case:
5713 * - after releasing the path above, someone has removed the item that
5714 * used to be at the very end of the block, and balance between leafs
5715 * gets another one with bigger key.offset to replace it.
5717 * This one should be returned as well, or we can get leaf corruption
5718 * later(esp. in __btrfs_drop_extents()).
5720 * And a bit more explanation about this check,
5721 * with ret > 0, the key isn't found, the path points to the slot
5722 * where it should be inserted, so the path->slots[0] item must be the
5725 if (nritems
> 0 && ret
> 0 && path
->slots
[0] == nritems
- 1) {
5730 while (level
< BTRFS_MAX_LEVEL
) {
5731 if (!path
->nodes
[level
]) {
5736 slot
= path
->slots
[level
] + 1;
5737 c
= path
->nodes
[level
];
5738 if (slot
>= btrfs_header_nritems(c
)) {
5740 if (level
== BTRFS_MAX_LEVEL
) {
5748 btrfs_tree_unlock_rw(next
, next_rw_lock
);
5749 free_extent_buffer(next
);
5753 next_rw_lock
= path
->locks
[level
];
5754 ret
= read_block_for_search(NULL
, root
, path
, &next
, level
,
5760 btrfs_release_path(path
);
5764 if (!path
->skip_locking
) {
5765 ret
= btrfs_try_tree_read_lock(next
);
5766 if (!ret
&& time_seq
) {
5768 * If we don't get the lock, we may be racing
5769 * with push_leaf_left, holding that lock while
5770 * itself waiting for the leaf we've currently
5771 * locked. To solve this situation, we give up
5772 * on our lock and cycle.
5774 free_extent_buffer(next
);
5775 btrfs_release_path(path
);
5780 btrfs_set_path_blocking(path
);
5781 btrfs_tree_read_lock(next
);
5782 btrfs_clear_path_blocking(path
, next
,
5785 next_rw_lock
= BTRFS_READ_LOCK
;
5789 path
->slots
[level
] = slot
;
5792 c
= path
->nodes
[level
];
5793 if (path
->locks
[level
])
5794 btrfs_tree_unlock_rw(c
, path
->locks
[level
]);
5796 free_extent_buffer(c
);
5797 path
->nodes
[level
] = next
;
5798 path
->slots
[level
] = 0;
5799 if (!path
->skip_locking
)
5800 path
->locks
[level
] = next_rw_lock
;
5804 ret
= read_block_for_search(NULL
, root
, path
, &next
, level
,
5810 btrfs_release_path(path
);
5814 if (!path
->skip_locking
) {
5815 ret
= btrfs_try_tree_read_lock(next
);
5817 btrfs_set_path_blocking(path
);
5818 btrfs_tree_read_lock(next
);
5819 btrfs_clear_path_blocking(path
, next
,
5822 next_rw_lock
= BTRFS_READ_LOCK
;
5827 unlock_up(path
, 0, 1, 0, NULL
);
5828 path
->leave_spinning
= old_spinning
;
5830 btrfs_set_path_blocking(path
);
5836 * this uses btrfs_prev_leaf to walk backwards in the tree, and keeps
5837 * searching until it gets past min_objectid or finds an item of 'type'
5839 * returns 0 if something is found, 1 if nothing was found and < 0 on error
5841 int btrfs_previous_item(struct btrfs_root
*root
,
5842 struct btrfs_path
*path
, u64 min_objectid
,
5845 struct btrfs_key found_key
;
5846 struct extent_buffer
*leaf
;
5851 if (path
->slots
[0] == 0) {
5852 btrfs_set_path_blocking(path
);
5853 ret
= btrfs_prev_leaf(root
, path
);
5859 leaf
= path
->nodes
[0];
5860 nritems
= btrfs_header_nritems(leaf
);
5863 if (path
->slots
[0] == nritems
)
5866 btrfs_item_key_to_cpu(leaf
, &found_key
, path
->slots
[0]);
5867 if (found_key
.objectid
< min_objectid
)
5869 if (found_key
.type
== type
)
5871 if (found_key
.objectid
== min_objectid
&&
5872 found_key
.type
< type
)
5879 * search in extent tree to find a previous Metadata/Data extent item with
5882 * returns 0 if something is found, 1 if nothing was found and < 0 on error
5884 int btrfs_previous_extent_item(struct btrfs_root
*root
,
5885 struct btrfs_path
*path
, u64 min_objectid
)
5887 struct btrfs_key found_key
;
5888 struct extent_buffer
*leaf
;
5893 if (path
->slots
[0] == 0) {
5894 btrfs_set_path_blocking(path
);
5895 ret
= btrfs_prev_leaf(root
, path
);
5901 leaf
= path
->nodes
[0];
5902 nritems
= btrfs_header_nritems(leaf
);
5905 if (path
->slots
[0] == nritems
)
5908 btrfs_item_key_to_cpu(leaf
, &found_key
, path
->slots
[0]);
5909 if (found_key
.objectid
< min_objectid
)
5911 if (found_key
.type
== BTRFS_EXTENT_ITEM_KEY
||
5912 found_key
.type
== BTRFS_METADATA_ITEM_KEY
)
5914 if (found_key
.objectid
== min_objectid
&&
5915 found_key
.type
< BTRFS_EXTENT_ITEM_KEY
)