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_free_block(trans
, root
, buf
->len
, 0,
262 new_root_objectid
, &disk_key
, level
,
267 copy_extent_buffer(cow
, buf
, 0, 0, cow
->len
);
268 btrfs_set_header_bytenr(cow
, cow
->start
);
269 btrfs_set_header_generation(cow
, trans
->transid
);
270 btrfs_set_header_backref_rev(cow
, BTRFS_MIXED_BACKREF_REV
);
271 btrfs_clear_header_flag(cow
, BTRFS_HEADER_FLAG_WRITTEN
|
272 BTRFS_HEADER_FLAG_RELOC
);
273 if (new_root_objectid
== BTRFS_TREE_RELOC_OBJECTID
)
274 btrfs_set_header_flag(cow
, BTRFS_HEADER_FLAG_RELOC
);
276 btrfs_set_header_owner(cow
, new_root_objectid
);
278 write_extent_buffer(cow
, root
->fs_info
->fsid
, btrfs_header_fsid(),
281 WARN_ON(btrfs_header_generation(buf
) > trans
->transid
);
282 if (new_root_objectid
== BTRFS_TREE_RELOC_OBJECTID
)
283 ret
= btrfs_inc_ref(trans
, root
, cow
, 1);
285 ret
= btrfs_inc_ref(trans
, root
, cow
, 0);
290 btrfs_mark_buffer_dirty(cow
);
299 MOD_LOG_KEY_REMOVE_WHILE_FREEING
,
300 MOD_LOG_KEY_REMOVE_WHILE_MOVING
,
302 MOD_LOG_ROOT_REPLACE
,
305 struct tree_mod_move
{
310 struct tree_mod_root
{
315 struct tree_mod_elem
{
317 u64 index
; /* shifted logical */
321 /* this is used for MOD_LOG_KEY_* and MOD_LOG_MOVE_KEYS operations */
324 /* this is used for MOD_LOG_KEY* and MOD_LOG_ROOT_REPLACE */
327 /* those are used for op == MOD_LOG_KEY_{REPLACE,REMOVE} */
328 struct btrfs_disk_key key
;
331 /* this is used for op == MOD_LOG_MOVE_KEYS */
332 struct tree_mod_move move
;
334 /* this is used for op == MOD_LOG_ROOT_REPLACE */
335 struct tree_mod_root old_root
;
338 static inline void tree_mod_log_read_lock(struct btrfs_fs_info
*fs_info
)
340 read_lock(&fs_info
->tree_mod_log_lock
);
343 static inline void tree_mod_log_read_unlock(struct btrfs_fs_info
*fs_info
)
345 read_unlock(&fs_info
->tree_mod_log_lock
);
348 static inline void tree_mod_log_write_lock(struct btrfs_fs_info
*fs_info
)
350 write_lock(&fs_info
->tree_mod_log_lock
);
353 static inline void tree_mod_log_write_unlock(struct btrfs_fs_info
*fs_info
)
355 write_unlock(&fs_info
->tree_mod_log_lock
);
359 * Pull a new tree mod seq number for our operation.
361 static inline u64
btrfs_inc_tree_mod_seq(struct btrfs_fs_info
*fs_info
)
363 return atomic64_inc_return(&fs_info
->tree_mod_seq
);
367 * This adds a new blocker to the tree mod log's blocker list if the @elem
368 * passed does not already have a sequence number set. So when a caller expects
369 * to record tree modifications, it should ensure to set elem->seq to zero
370 * before calling btrfs_get_tree_mod_seq.
371 * Returns a fresh, unused tree log modification sequence number, even if no new
374 u64
btrfs_get_tree_mod_seq(struct btrfs_fs_info
*fs_info
,
375 struct seq_list
*elem
)
377 tree_mod_log_write_lock(fs_info
);
378 spin_lock(&fs_info
->tree_mod_seq_lock
);
380 elem
->seq
= btrfs_inc_tree_mod_seq(fs_info
);
381 list_add_tail(&elem
->list
, &fs_info
->tree_mod_seq_list
);
383 spin_unlock(&fs_info
->tree_mod_seq_lock
);
384 tree_mod_log_write_unlock(fs_info
);
389 void btrfs_put_tree_mod_seq(struct btrfs_fs_info
*fs_info
,
390 struct seq_list
*elem
)
392 struct rb_root
*tm_root
;
393 struct rb_node
*node
;
394 struct rb_node
*next
;
395 struct seq_list
*cur_elem
;
396 struct tree_mod_elem
*tm
;
397 u64 min_seq
= (u64
)-1;
398 u64 seq_putting
= elem
->seq
;
403 spin_lock(&fs_info
->tree_mod_seq_lock
);
404 list_del(&elem
->list
);
407 list_for_each_entry(cur_elem
, &fs_info
->tree_mod_seq_list
, list
) {
408 if (cur_elem
->seq
< min_seq
) {
409 if (seq_putting
> cur_elem
->seq
) {
411 * blocker with lower sequence number exists, we
412 * cannot remove anything from the log
414 spin_unlock(&fs_info
->tree_mod_seq_lock
);
417 min_seq
= cur_elem
->seq
;
420 spin_unlock(&fs_info
->tree_mod_seq_lock
);
423 * anything that's lower than the lowest existing (read: blocked)
424 * sequence number can be removed from the tree.
426 tree_mod_log_write_lock(fs_info
);
427 tm_root
= &fs_info
->tree_mod_log
;
428 for (node
= rb_first(tm_root
); node
; node
= next
) {
429 next
= rb_next(node
);
430 tm
= container_of(node
, struct tree_mod_elem
, node
);
431 if (tm
->seq
> min_seq
)
433 rb_erase(node
, tm_root
);
436 tree_mod_log_write_unlock(fs_info
);
440 * key order of the log:
443 * the index is the shifted logical of the *new* root node for root replace
444 * operations, or the shifted logical of the affected block for all other
447 * Note: must be called with write lock (tree_mod_log_write_lock).
450 __tree_mod_log_insert(struct btrfs_fs_info
*fs_info
, struct tree_mod_elem
*tm
)
452 struct rb_root
*tm_root
;
453 struct rb_node
**new;
454 struct rb_node
*parent
= NULL
;
455 struct tree_mod_elem
*cur
;
459 tm
->seq
= btrfs_inc_tree_mod_seq(fs_info
);
461 tm_root
= &fs_info
->tree_mod_log
;
462 new = &tm_root
->rb_node
;
464 cur
= container_of(*new, struct tree_mod_elem
, node
);
466 if (cur
->index
< tm
->index
)
467 new = &((*new)->rb_left
);
468 else if (cur
->index
> tm
->index
)
469 new = &((*new)->rb_right
);
470 else if (cur
->seq
< tm
->seq
)
471 new = &((*new)->rb_left
);
472 else if (cur
->seq
> tm
->seq
)
473 new = &((*new)->rb_right
);
478 rb_link_node(&tm
->node
, parent
, new);
479 rb_insert_color(&tm
->node
, tm_root
);
484 * Determines if logging can be omitted. Returns 1 if it can. Otherwise, it
485 * returns zero with the tree_mod_log_lock acquired. The caller must hold
486 * this until all tree mod log insertions are recorded in the rb tree and then
487 * call tree_mod_log_write_unlock() to release.
489 static inline int tree_mod_dont_log(struct btrfs_fs_info
*fs_info
,
490 struct extent_buffer
*eb
) {
492 if (list_empty(&(fs_info
)->tree_mod_seq_list
))
494 if (eb
&& btrfs_header_level(eb
) == 0)
497 tree_mod_log_write_lock(fs_info
);
498 if (list_empty(&(fs_info
)->tree_mod_seq_list
)) {
499 tree_mod_log_write_unlock(fs_info
);
506 /* Similar to tree_mod_dont_log, but doesn't acquire any locks. */
507 static inline int tree_mod_need_log(const struct btrfs_fs_info
*fs_info
,
508 struct extent_buffer
*eb
)
511 if (list_empty(&(fs_info
)->tree_mod_seq_list
))
513 if (eb
&& btrfs_header_level(eb
) == 0)
519 static struct tree_mod_elem
*
520 alloc_tree_mod_elem(struct extent_buffer
*eb
, int slot
,
521 enum mod_log_op op
, gfp_t flags
)
523 struct tree_mod_elem
*tm
;
525 tm
= kzalloc(sizeof(*tm
), flags
);
529 tm
->index
= eb
->start
>> PAGE_CACHE_SHIFT
;
530 if (op
!= MOD_LOG_KEY_ADD
) {
531 btrfs_node_key(eb
, &tm
->key
, slot
);
532 tm
->blockptr
= btrfs_node_blockptr(eb
, slot
);
536 tm
->generation
= btrfs_node_ptr_generation(eb
, slot
);
537 RB_CLEAR_NODE(&tm
->node
);
543 tree_mod_log_insert_key(struct btrfs_fs_info
*fs_info
,
544 struct extent_buffer
*eb
, int slot
,
545 enum mod_log_op op
, gfp_t flags
)
547 struct tree_mod_elem
*tm
;
550 if (!tree_mod_need_log(fs_info
, eb
))
553 tm
= alloc_tree_mod_elem(eb
, slot
, op
, flags
);
557 if (tree_mod_dont_log(fs_info
, eb
)) {
562 ret
= __tree_mod_log_insert(fs_info
, tm
);
563 tree_mod_log_write_unlock(fs_info
);
571 tree_mod_log_insert_move(struct btrfs_fs_info
*fs_info
,
572 struct extent_buffer
*eb
, int dst_slot
, int src_slot
,
573 int nr_items
, gfp_t flags
)
575 struct tree_mod_elem
*tm
= NULL
;
576 struct tree_mod_elem
**tm_list
= NULL
;
581 if (!tree_mod_need_log(fs_info
, eb
))
584 tm_list
= kzalloc(nr_items
* sizeof(struct tree_mod_elem
*), flags
);
588 tm
= kzalloc(sizeof(*tm
), flags
);
594 tm
->index
= eb
->start
>> PAGE_CACHE_SHIFT
;
596 tm
->move
.dst_slot
= dst_slot
;
597 tm
->move
.nr_items
= nr_items
;
598 tm
->op
= MOD_LOG_MOVE_KEYS
;
600 for (i
= 0; i
+ dst_slot
< src_slot
&& i
< nr_items
; i
++) {
601 tm_list
[i
] = alloc_tree_mod_elem(eb
, i
+ dst_slot
,
602 MOD_LOG_KEY_REMOVE_WHILE_MOVING
, flags
);
609 if (tree_mod_dont_log(fs_info
, eb
))
614 * When we override something during the move, we log these removals.
615 * This can only happen when we move towards the beginning of the
616 * buffer, i.e. dst_slot < src_slot.
618 for (i
= 0; i
+ dst_slot
< src_slot
&& i
< nr_items
; i
++) {
619 ret
= __tree_mod_log_insert(fs_info
, tm_list
[i
]);
624 ret
= __tree_mod_log_insert(fs_info
, tm
);
627 tree_mod_log_write_unlock(fs_info
);
632 for (i
= 0; i
< nr_items
; i
++) {
633 if (tm_list
[i
] && !RB_EMPTY_NODE(&tm_list
[i
]->node
))
634 rb_erase(&tm_list
[i
]->node
, &fs_info
->tree_mod_log
);
638 tree_mod_log_write_unlock(fs_info
);
646 __tree_mod_log_free_eb(struct btrfs_fs_info
*fs_info
,
647 struct tree_mod_elem
**tm_list
,
653 for (i
= nritems
- 1; i
>= 0; i
--) {
654 ret
= __tree_mod_log_insert(fs_info
, tm_list
[i
]);
656 for (j
= nritems
- 1; j
> i
; j
--)
657 rb_erase(&tm_list
[j
]->node
,
658 &fs_info
->tree_mod_log
);
667 tree_mod_log_insert_root(struct btrfs_fs_info
*fs_info
,
668 struct extent_buffer
*old_root
,
669 struct extent_buffer
*new_root
, gfp_t flags
,
672 struct tree_mod_elem
*tm
= NULL
;
673 struct tree_mod_elem
**tm_list
= NULL
;
678 if (!tree_mod_need_log(fs_info
, NULL
))
681 if (log_removal
&& btrfs_header_level(old_root
) > 0) {
682 nritems
= btrfs_header_nritems(old_root
);
683 tm_list
= kzalloc(nritems
* sizeof(struct tree_mod_elem
*),
689 for (i
= 0; i
< nritems
; i
++) {
690 tm_list
[i
] = alloc_tree_mod_elem(old_root
, i
,
691 MOD_LOG_KEY_REMOVE_WHILE_FREEING
, flags
);
699 tm
= kzalloc(sizeof(*tm
), flags
);
705 tm
->index
= new_root
->start
>> PAGE_CACHE_SHIFT
;
706 tm
->old_root
.logical
= old_root
->start
;
707 tm
->old_root
.level
= btrfs_header_level(old_root
);
708 tm
->generation
= btrfs_header_generation(old_root
);
709 tm
->op
= MOD_LOG_ROOT_REPLACE
;
711 if (tree_mod_dont_log(fs_info
, NULL
))
715 ret
= __tree_mod_log_free_eb(fs_info
, tm_list
, nritems
);
717 ret
= __tree_mod_log_insert(fs_info
, tm
);
719 tree_mod_log_write_unlock(fs_info
);
728 for (i
= 0; i
< nritems
; i
++)
737 static struct tree_mod_elem
*
738 __tree_mod_log_search(struct btrfs_fs_info
*fs_info
, u64 start
, u64 min_seq
,
741 struct rb_root
*tm_root
;
742 struct rb_node
*node
;
743 struct tree_mod_elem
*cur
= NULL
;
744 struct tree_mod_elem
*found
= NULL
;
745 u64 index
= start
>> PAGE_CACHE_SHIFT
;
747 tree_mod_log_read_lock(fs_info
);
748 tm_root
= &fs_info
->tree_mod_log
;
749 node
= tm_root
->rb_node
;
751 cur
= container_of(node
, struct tree_mod_elem
, node
);
752 if (cur
->index
< index
) {
753 node
= node
->rb_left
;
754 } else if (cur
->index
> index
) {
755 node
= node
->rb_right
;
756 } else if (cur
->seq
< min_seq
) {
757 node
= node
->rb_left
;
758 } else if (!smallest
) {
759 /* we want the node with the highest seq */
761 BUG_ON(found
->seq
> cur
->seq
);
763 node
= node
->rb_left
;
764 } else if (cur
->seq
> min_seq
) {
765 /* we want the node with the smallest seq */
767 BUG_ON(found
->seq
< cur
->seq
);
769 node
= node
->rb_right
;
775 tree_mod_log_read_unlock(fs_info
);
781 * this returns the element from the log with the smallest time sequence
782 * value that's in the log (the oldest log item). any element with a time
783 * sequence lower than min_seq will be ignored.
785 static struct tree_mod_elem
*
786 tree_mod_log_search_oldest(struct btrfs_fs_info
*fs_info
, u64 start
,
789 return __tree_mod_log_search(fs_info
, start
, min_seq
, 1);
793 * this returns the element from the log with the largest time sequence
794 * value that's in the log (the most recent log item). any element with
795 * a time sequence lower than min_seq will be ignored.
797 static struct tree_mod_elem
*
798 tree_mod_log_search(struct btrfs_fs_info
*fs_info
, u64 start
, u64 min_seq
)
800 return __tree_mod_log_search(fs_info
, start
, min_seq
, 0);
804 tree_mod_log_eb_copy(struct btrfs_fs_info
*fs_info
, struct extent_buffer
*dst
,
805 struct extent_buffer
*src
, unsigned long dst_offset
,
806 unsigned long src_offset
, int nr_items
)
809 struct tree_mod_elem
**tm_list
= NULL
;
810 struct tree_mod_elem
**tm_list_add
, **tm_list_rem
;
814 if (!tree_mod_need_log(fs_info
, NULL
))
817 if (btrfs_header_level(dst
) == 0 && btrfs_header_level(src
) == 0)
820 tm_list
= kzalloc(nr_items
* 2 * sizeof(struct tree_mod_elem
*),
825 tm_list_add
= tm_list
;
826 tm_list_rem
= tm_list
+ nr_items
;
827 for (i
= 0; i
< nr_items
; i
++) {
828 tm_list_rem
[i
] = alloc_tree_mod_elem(src
, i
+ src_offset
,
829 MOD_LOG_KEY_REMOVE
, GFP_NOFS
);
830 if (!tm_list_rem
[i
]) {
835 tm_list_add
[i
] = alloc_tree_mod_elem(dst
, i
+ dst_offset
,
836 MOD_LOG_KEY_ADD
, GFP_NOFS
);
837 if (!tm_list_add
[i
]) {
843 if (tree_mod_dont_log(fs_info
, NULL
))
847 for (i
= 0; i
< nr_items
; i
++) {
848 ret
= __tree_mod_log_insert(fs_info
, tm_list_rem
[i
]);
851 ret
= __tree_mod_log_insert(fs_info
, tm_list_add
[i
]);
856 tree_mod_log_write_unlock(fs_info
);
862 for (i
= 0; i
< nr_items
* 2; i
++) {
863 if (tm_list
[i
] && !RB_EMPTY_NODE(&tm_list
[i
]->node
))
864 rb_erase(&tm_list
[i
]->node
, &fs_info
->tree_mod_log
);
868 tree_mod_log_write_unlock(fs_info
);
875 tree_mod_log_eb_move(struct btrfs_fs_info
*fs_info
, struct extent_buffer
*dst
,
876 int dst_offset
, int src_offset
, int nr_items
)
879 ret
= tree_mod_log_insert_move(fs_info
, dst
, dst_offset
, src_offset
,
885 tree_mod_log_set_node_key(struct btrfs_fs_info
*fs_info
,
886 struct extent_buffer
*eb
, int slot
, int atomic
)
890 ret
= tree_mod_log_insert_key(fs_info
, eb
, slot
,
892 atomic
? GFP_ATOMIC
: GFP_NOFS
);
897 tree_mod_log_free_eb(struct btrfs_fs_info
*fs_info
, struct extent_buffer
*eb
)
899 struct tree_mod_elem
**tm_list
= NULL
;
904 if (btrfs_header_level(eb
) == 0)
907 if (!tree_mod_need_log(fs_info
, NULL
))
910 nritems
= btrfs_header_nritems(eb
);
911 tm_list
= kzalloc(nritems
* sizeof(struct tree_mod_elem
*),
916 for (i
= 0; i
< nritems
; i
++) {
917 tm_list
[i
] = alloc_tree_mod_elem(eb
, i
,
918 MOD_LOG_KEY_REMOVE_WHILE_FREEING
, GFP_NOFS
);
925 if (tree_mod_dont_log(fs_info
, eb
))
928 ret
= __tree_mod_log_free_eb(fs_info
, tm_list
, nritems
);
929 tree_mod_log_write_unlock(fs_info
);
937 for (i
= 0; i
< nritems
; i
++)
945 tree_mod_log_set_root_pointer(struct btrfs_root
*root
,
946 struct extent_buffer
*new_root_node
,
950 ret
= tree_mod_log_insert_root(root
->fs_info
, root
->node
,
951 new_root_node
, GFP_NOFS
, log_removal
);
956 * check if the tree block can be shared by multiple trees
958 int btrfs_block_can_be_shared(struct btrfs_root
*root
,
959 struct extent_buffer
*buf
)
962 * Tree blocks not in refernece counted trees and tree roots
963 * are never shared. If a block was allocated after the last
964 * snapshot and the block was not allocated by tree relocation,
965 * we know the block is not shared.
967 if (test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
968 buf
!= root
->node
&& buf
!= root
->commit_root
&&
969 (btrfs_header_generation(buf
) <=
970 btrfs_root_last_snapshot(&root
->root_item
) ||
971 btrfs_header_flag(buf
, BTRFS_HEADER_FLAG_RELOC
)))
973 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
974 if (test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
975 btrfs_header_backref_rev(buf
) < BTRFS_MIXED_BACKREF_REV
)
981 static noinline
int update_ref_for_cow(struct btrfs_trans_handle
*trans
,
982 struct btrfs_root
*root
,
983 struct extent_buffer
*buf
,
984 struct extent_buffer
*cow
,
994 * Backrefs update rules:
996 * Always use full backrefs for extent pointers in tree block
997 * allocated by tree relocation.
999 * If a shared tree block is no longer referenced by its owner
1000 * tree (btrfs_header_owner(buf) == root->root_key.objectid),
1001 * use full backrefs for extent pointers in tree block.
1003 * If a tree block is been relocating
1004 * (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID),
1005 * use full backrefs for extent pointers in tree block.
1006 * The reason for this is some operations (such as drop tree)
1007 * are only allowed for blocks use full backrefs.
1010 if (btrfs_block_can_be_shared(root
, buf
)) {
1011 ret
= btrfs_lookup_extent_info(trans
, root
, buf
->start
,
1012 btrfs_header_level(buf
), 1,
1018 btrfs_std_error(root
->fs_info
, ret
);
1023 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
||
1024 btrfs_header_backref_rev(buf
) < BTRFS_MIXED_BACKREF_REV
)
1025 flags
= BTRFS_BLOCK_FLAG_FULL_BACKREF
;
1030 owner
= btrfs_header_owner(buf
);
1031 BUG_ON(owner
== BTRFS_TREE_RELOC_OBJECTID
&&
1032 !(flags
& BTRFS_BLOCK_FLAG_FULL_BACKREF
));
1035 if ((owner
== root
->root_key
.objectid
||
1036 root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
) &&
1037 !(flags
& BTRFS_BLOCK_FLAG_FULL_BACKREF
)) {
1038 ret
= btrfs_inc_ref(trans
, root
, buf
, 1);
1039 BUG_ON(ret
); /* -ENOMEM */
1041 if (root
->root_key
.objectid
==
1042 BTRFS_TREE_RELOC_OBJECTID
) {
1043 ret
= btrfs_dec_ref(trans
, root
, buf
, 0);
1044 BUG_ON(ret
); /* -ENOMEM */
1045 ret
= btrfs_inc_ref(trans
, root
, cow
, 1);
1046 BUG_ON(ret
); /* -ENOMEM */
1048 new_flags
|= BTRFS_BLOCK_FLAG_FULL_BACKREF
;
1051 if (root
->root_key
.objectid
==
1052 BTRFS_TREE_RELOC_OBJECTID
)
1053 ret
= btrfs_inc_ref(trans
, root
, cow
, 1);
1055 ret
= btrfs_inc_ref(trans
, root
, cow
, 0);
1056 BUG_ON(ret
); /* -ENOMEM */
1058 if (new_flags
!= 0) {
1059 int level
= btrfs_header_level(buf
);
1061 ret
= btrfs_set_disk_extent_flags(trans
, root
,
1064 new_flags
, level
, 0);
1069 if (flags
& BTRFS_BLOCK_FLAG_FULL_BACKREF
) {
1070 if (root
->root_key
.objectid
==
1071 BTRFS_TREE_RELOC_OBJECTID
)
1072 ret
= btrfs_inc_ref(trans
, root
, cow
, 1);
1074 ret
= btrfs_inc_ref(trans
, root
, cow
, 0);
1075 BUG_ON(ret
); /* -ENOMEM */
1076 ret
= btrfs_dec_ref(trans
, root
, buf
, 1);
1077 BUG_ON(ret
); /* -ENOMEM */
1079 clean_tree_block(trans
, root
, buf
);
1086 * does the dirty work in cow of a single block. The parent block (if
1087 * supplied) is updated to point to the new cow copy. The new buffer is marked
1088 * dirty and returned locked. If you modify the block it needs to be marked
1091 * search_start -- an allocation hint for the new block
1093 * empty_size -- a hint that you plan on doing more cow. This is the size in
1094 * bytes the allocator should try to find free next to the block it returns.
1095 * This is just a hint and may be ignored by the allocator.
1097 static noinline
int __btrfs_cow_block(struct btrfs_trans_handle
*trans
,
1098 struct btrfs_root
*root
,
1099 struct extent_buffer
*buf
,
1100 struct extent_buffer
*parent
, int parent_slot
,
1101 struct extent_buffer
**cow_ret
,
1102 u64 search_start
, u64 empty_size
)
1104 struct btrfs_disk_key disk_key
;
1105 struct extent_buffer
*cow
;
1108 int unlock_orig
= 0;
1111 if (*cow_ret
== buf
)
1114 btrfs_assert_tree_locked(buf
);
1116 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
1117 trans
->transid
!= root
->fs_info
->running_transaction
->transid
);
1118 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
1119 trans
->transid
!= root
->last_trans
);
1121 level
= btrfs_header_level(buf
);
1124 btrfs_item_key(buf
, &disk_key
, 0);
1126 btrfs_node_key(buf
, &disk_key
, 0);
1128 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
) {
1130 parent_start
= parent
->start
;
1136 cow
= btrfs_alloc_free_block(trans
, root
, buf
->len
, parent_start
,
1137 root
->root_key
.objectid
, &disk_key
,
1138 level
, search_start
, empty_size
);
1140 return PTR_ERR(cow
);
1142 /* cow is set to blocking by btrfs_init_new_buffer */
1144 copy_extent_buffer(cow
, buf
, 0, 0, cow
->len
);
1145 btrfs_set_header_bytenr(cow
, cow
->start
);
1146 btrfs_set_header_generation(cow
, trans
->transid
);
1147 btrfs_set_header_backref_rev(cow
, BTRFS_MIXED_BACKREF_REV
);
1148 btrfs_clear_header_flag(cow
, BTRFS_HEADER_FLAG_WRITTEN
|
1149 BTRFS_HEADER_FLAG_RELOC
);
1150 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
)
1151 btrfs_set_header_flag(cow
, BTRFS_HEADER_FLAG_RELOC
);
1153 btrfs_set_header_owner(cow
, root
->root_key
.objectid
);
1155 write_extent_buffer(cow
, root
->fs_info
->fsid
, btrfs_header_fsid(),
1158 ret
= update_ref_for_cow(trans
, root
, buf
, cow
, &last_ref
);
1160 btrfs_abort_transaction(trans
, root
, ret
);
1164 if (test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
)) {
1165 ret
= btrfs_reloc_cow_block(trans
, root
, buf
, cow
);
1170 if (buf
== root
->node
) {
1171 WARN_ON(parent
&& parent
!= buf
);
1172 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
||
1173 btrfs_header_backref_rev(buf
) < BTRFS_MIXED_BACKREF_REV
)
1174 parent_start
= buf
->start
;
1178 extent_buffer_get(cow
);
1179 tree_mod_log_set_root_pointer(root
, cow
, 1);
1180 rcu_assign_pointer(root
->node
, cow
);
1182 btrfs_free_tree_block(trans
, root
, buf
, parent_start
,
1184 free_extent_buffer(buf
);
1185 add_root_to_dirty_list(root
);
1187 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
)
1188 parent_start
= parent
->start
;
1192 WARN_ON(trans
->transid
!= btrfs_header_generation(parent
));
1193 tree_mod_log_insert_key(root
->fs_info
, parent
, parent_slot
,
1194 MOD_LOG_KEY_REPLACE
, GFP_NOFS
);
1195 btrfs_set_node_blockptr(parent
, parent_slot
,
1197 btrfs_set_node_ptr_generation(parent
, parent_slot
,
1199 btrfs_mark_buffer_dirty(parent
);
1201 ret
= tree_mod_log_free_eb(root
->fs_info
, buf
);
1203 btrfs_abort_transaction(trans
, root
, ret
);
1207 btrfs_free_tree_block(trans
, root
, buf
, parent_start
,
1211 btrfs_tree_unlock(buf
);
1212 free_extent_buffer_stale(buf
);
1213 btrfs_mark_buffer_dirty(cow
);
1219 * returns the logical address of the oldest predecessor of the given root.
1220 * entries older than time_seq are ignored.
1222 static struct tree_mod_elem
*
1223 __tree_mod_log_oldest_root(struct btrfs_fs_info
*fs_info
,
1224 struct extent_buffer
*eb_root
, u64 time_seq
)
1226 struct tree_mod_elem
*tm
;
1227 struct tree_mod_elem
*found
= NULL
;
1228 u64 root_logical
= eb_root
->start
;
1235 * the very last operation that's logged for a root is the replacement
1236 * operation (if it is replaced at all). this has the index of the *new*
1237 * root, making it the very first operation that's logged for this root.
1240 tm
= tree_mod_log_search_oldest(fs_info
, root_logical
,
1245 * if there are no tree operation for the oldest root, we simply
1246 * return it. this should only happen if that (old) root is at
1253 * if there's an operation that's not a root replacement, we
1254 * found the oldest version of our root. normally, we'll find a
1255 * MOD_LOG_KEY_REMOVE_WHILE_FREEING operation here.
1257 if (tm
->op
!= MOD_LOG_ROOT_REPLACE
)
1261 root_logical
= tm
->old_root
.logical
;
1265 /* if there's no old root to return, return what we found instead */
1273 * tm is a pointer to the first operation to rewind within eb. then, all
1274 * previous operations will be rewinded (until we reach something older than
1278 __tree_mod_log_rewind(struct btrfs_fs_info
*fs_info
, struct extent_buffer
*eb
,
1279 u64 time_seq
, struct tree_mod_elem
*first_tm
)
1282 struct rb_node
*next
;
1283 struct tree_mod_elem
*tm
= first_tm
;
1284 unsigned long o_dst
;
1285 unsigned long o_src
;
1286 unsigned long p_size
= sizeof(struct btrfs_key_ptr
);
1288 n
= btrfs_header_nritems(eb
);
1289 tree_mod_log_read_lock(fs_info
);
1290 while (tm
&& tm
->seq
>= time_seq
) {
1292 * all the operations are recorded with the operator used for
1293 * the modification. as we're going backwards, we do the
1294 * opposite of each operation here.
1297 case MOD_LOG_KEY_REMOVE_WHILE_FREEING
:
1298 BUG_ON(tm
->slot
< n
);
1300 case MOD_LOG_KEY_REMOVE_WHILE_MOVING
:
1301 case MOD_LOG_KEY_REMOVE
:
1302 btrfs_set_node_key(eb
, &tm
->key
, tm
->slot
);
1303 btrfs_set_node_blockptr(eb
, tm
->slot
, tm
->blockptr
);
1304 btrfs_set_node_ptr_generation(eb
, tm
->slot
,
1308 case MOD_LOG_KEY_REPLACE
:
1309 BUG_ON(tm
->slot
>= n
);
1310 btrfs_set_node_key(eb
, &tm
->key
, tm
->slot
);
1311 btrfs_set_node_blockptr(eb
, tm
->slot
, tm
->blockptr
);
1312 btrfs_set_node_ptr_generation(eb
, tm
->slot
,
1315 case MOD_LOG_KEY_ADD
:
1316 /* if a move operation is needed it's in the log */
1319 case MOD_LOG_MOVE_KEYS
:
1320 o_dst
= btrfs_node_key_ptr_offset(tm
->slot
);
1321 o_src
= btrfs_node_key_ptr_offset(tm
->move
.dst_slot
);
1322 memmove_extent_buffer(eb
, o_dst
, o_src
,
1323 tm
->move
.nr_items
* p_size
);
1325 case MOD_LOG_ROOT_REPLACE
:
1327 * this operation is special. for roots, this must be
1328 * handled explicitly before rewinding.
1329 * for non-roots, this operation may exist if the node
1330 * was a root: root A -> child B; then A gets empty and
1331 * B is promoted to the new root. in the mod log, we'll
1332 * have a root-replace operation for B, a tree block
1333 * that is no root. we simply ignore that operation.
1337 next
= rb_next(&tm
->node
);
1340 tm
= container_of(next
, struct tree_mod_elem
, node
);
1341 if (tm
->index
!= first_tm
->index
)
1344 tree_mod_log_read_unlock(fs_info
);
1345 btrfs_set_header_nritems(eb
, n
);
1349 * Called with eb read locked. If the buffer cannot be rewinded, the same buffer
1350 * is returned. If rewind operations happen, a fresh buffer is returned. The
1351 * returned buffer is always read-locked. If the returned buffer is not the
1352 * input buffer, the lock on the input buffer is released and the input buffer
1353 * is freed (its refcount is decremented).
1355 static struct extent_buffer
*
1356 tree_mod_log_rewind(struct btrfs_fs_info
*fs_info
, struct btrfs_path
*path
,
1357 struct extent_buffer
*eb
, u64 time_seq
)
1359 struct extent_buffer
*eb_rewin
;
1360 struct tree_mod_elem
*tm
;
1365 if (btrfs_header_level(eb
) == 0)
1368 tm
= tree_mod_log_search(fs_info
, eb
->start
, time_seq
);
1372 btrfs_set_path_blocking(path
);
1373 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1375 if (tm
->op
== MOD_LOG_KEY_REMOVE_WHILE_FREEING
) {
1376 BUG_ON(tm
->slot
!= 0);
1377 eb_rewin
= alloc_dummy_extent_buffer(eb
->start
,
1378 fs_info
->tree_root
->nodesize
);
1380 btrfs_tree_read_unlock_blocking(eb
);
1381 free_extent_buffer(eb
);
1384 btrfs_set_header_bytenr(eb_rewin
, eb
->start
);
1385 btrfs_set_header_backref_rev(eb_rewin
,
1386 btrfs_header_backref_rev(eb
));
1387 btrfs_set_header_owner(eb_rewin
, btrfs_header_owner(eb
));
1388 btrfs_set_header_level(eb_rewin
, btrfs_header_level(eb
));
1390 eb_rewin
= btrfs_clone_extent_buffer(eb
);
1392 btrfs_tree_read_unlock_blocking(eb
);
1393 free_extent_buffer(eb
);
1398 btrfs_clear_path_blocking(path
, NULL
, BTRFS_READ_LOCK
);
1399 btrfs_tree_read_unlock_blocking(eb
);
1400 free_extent_buffer(eb
);
1402 extent_buffer_get(eb_rewin
);
1403 btrfs_tree_read_lock(eb_rewin
);
1404 __tree_mod_log_rewind(fs_info
, eb_rewin
, time_seq
, tm
);
1405 WARN_ON(btrfs_header_nritems(eb_rewin
) >
1406 BTRFS_NODEPTRS_PER_BLOCK(fs_info
->tree_root
));
1412 * get_old_root() rewinds the state of @root's root node to the given @time_seq
1413 * value. If there are no changes, the current root->root_node is returned. If
1414 * anything changed in between, there's a fresh buffer allocated on which the
1415 * rewind operations are done. In any case, the returned buffer is read locked.
1416 * Returns NULL on error (with no locks held).
1418 static inline struct extent_buffer
*
1419 get_old_root(struct btrfs_root
*root
, u64 time_seq
)
1421 struct tree_mod_elem
*tm
;
1422 struct extent_buffer
*eb
= NULL
;
1423 struct extent_buffer
*eb_root
;
1424 struct extent_buffer
*old
;
1425 struct tree_mod_root
*old_root
= NULL
;
1426 u64 old_generation
= 0;
1429 eb_root
= btrfs_read_lock_root_node(root
);
1430 tm
= __tree_mod_log_oldest_root(root
->fs_info
, eb_root
, time_seq
);
1434 if (tm
->op
== MOD_LOG_ROOT_REPLACE
) {
1435 old_root
= &tm
->old_root
;
1436 old_generation
= tm
->generation
;
1437 logical
= old_root
->logical
;
1439 logical
= eb_root
->start
;
1442 tm
= tree_mod_log_search(root
->fs_info
, logical
, time_seq
);
1443 if (old_root
&& tm
&& tm
->op
!= MOD_LOG_KEY_REMOVE_WHILE_FREEING
) {
1444 btrfs_tree_read_unlock(eb_root
);
1445 free_extent_buffer(eb_root
);
1446 old
= read_tree_block(root
, logical
, 0);
1447 if (WARN_ON(!old
|| !extent_buffer_uptodate(old
))) {
1448 free_extent_buffer(old
);
1449 btrfs_warn(root
->fs_info
,
1450 "failed to read tree block %llu from get_old_root", logical
);
1452 eb
= btrfs_clone_extent_buffer(old
);
1453 free_extent_buffer(old
);
1455 } else if (old_root
) {
1456 btrfs_tree_read_unlock(eb_root
);
1457 free_extent_buffer(eb_root
);
1458 eb
= alloc_dummy_extent_buffer(logical
, root
->nodesize
);
1460 btrfs_set_lock_blocking_rw(eb_root
, BTRFS_READ_LOCK
);
1461 eb
= btrfs_clone_extent_buffer(eb_root
);
1462 btrfs_tree_read_unlock_blocking(eb_root
);
1463 free_extent_buffer(eb_root
);
1468 extent_buffer_get(eb
);
1469 btrfs_tree_read_lock(eb
);
1471 btrfs_set_header_bytenr(eb
, eb
->start
);
1472 btrfs_set_header_backref_rev(eb
, BTRFS_MIXED_BACKREF_REV
);
1473 btrfs_set_header_owner(eb
, btrfs_header_owner(eb_root
));
1474 btrfs_set_header_level(eb
, old_root
->level
);
1475 btrfs_set_header_generation(eb
, old_generation
);
1478 __tree_mod_log_rewind(root
->fs_info
, eb
, time_seq
, tm
);
1480 WARN_ON(btrfs_header_level(eb
) != 0);
1481 WARN_ON(btrfs_header_nritems(eb
) > BTRFS_NODEPTRS_PER_BLOCK(root
));
1486 int btrfs_old_root_level(struct btrfs_root
*root
, u64 time_seq
)
1488 struct tree_mod_elem
*tm
;
1490 struct extent_buffer
*eb_root
= btrfs_root_node(root
);
1492 tm
= __tree_mod_log_oldest_root(root
->fs_info
, eb_root
, time_seq
);
1493 if (tm
&& tm
->op
== MOD_LOG_ROOT_REPLACE
) {
1494 level
= tm
->old_root
.level
;
1496 level
= btrfs_header_level(eb_root
);
1498 free_extent_buffer(eb_root
);
1503 static inline int should_cow_block(struct btrfs_trans_handle
*trans
,
1504 struct btrfs_root
*root
,
1505 struct extent_buffer
*buf
)
1507 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
1508 if (unlikely(test_bit(BTRFS_ROOT_DUMMY_ROOT
, &root
->state
)))
1511 /* ensure we can see the force_cow */
1515 * We do not need to cow a block if
1516 * 1) this block is not created or changed in this transaction;
1517 * 2) this block does not belong to TREE_RELOC tree;
1518 * 3) the root is not forced COW.
1520 * What is forced COW:
1521 * when we create snapshot during commiting the transaction,
1522 * after we've finished coping src root, we must COW the shared
1523 * block to ensure the metadata consistency.
1525 if (btrfs_header_generation(buf
) == trans
->transid
&&
1526 !btrfs_header_flag(buf
, BTRFS_HEADER_FLAG_WRITTEN
) &&
1527 !(root
->root_key
.objectid
!= BTRFS_TREE_RELOC_OBJECTID
&&
1528 btrfs_header_flag(buf
, BTRFS_HEADER_FLAG_RELOC
)) &&
1529 !test_bit(BTRFS_ROOT_FORCE_COW
, &root
->state
))
1535 * cows a single block, see __btrfs_cow_block for the real work.
1536 * This version of it has extra checks so that a block isn't cow'd more than
1537 * once per transaction, as long as it hasn't been written yet
1539 noinline
int btrfs_cow_block(struct btrfs_trans_handle
*trans
,
1540 struct btrfs_root
*root
, struct extent_buffer
*buf
,
1541 struct extent_buffer
*parent
, int parent_slot
,
1542 struct extent_buffer
**cow_ret
)
1547 if (trans
->transaction
!= root
->fs_info
->running_transaction
)
1548 WARN(1, KERN_CRIT
"trans %llu running %llu\n",
1550 root
->fs_info
->running_transaction
->transid
);
1552 if (trans
->transid
!= root
->fs_info
->generation
)
1553 WARN(1, KERN_CRIT
"trans %llu running %llu\n",
1554 trans
->transid
, root
->fs_info
->generation
);
1556 if (!should_cow_block(trans
, root
, buf
)) {
1561 search_start
= buf
->start
& ~((u64
)(1024 * 1024 * 1024) - 1);
1564 btrfs_set_lock_blocking(parent
);
1565 btrfs_set_lock_blocking(buf
);
1567 ret
= __btrfs_cow_block(trans
, root
, buf
, parent
,
1568 parent_slot
, cow_ret
, search_start
, 0);
1570 trace_btrfs_cow_block(root
, buf
, *cow_ret
);
1576 * helper function for defrag to decide if two blocks pointed to by a
1577 * node are actually close by
1579 static int close_blocks(u64 blocknr
, u64 other
, u32 blocksize
)
1581 if (blocknr
< other
&& other
- (blocknr
+ blocksize
) < 32768)
1583 if (blocknr
> other
&& blocknr
- (other
+ blocksize
) < 32768)
1589 * compare two keys in a memcmp fashion
1591 static int comp_keys(struct btrfs_disk_key
*disk
, struct btrfs_key
*k2
)
1593 struct btrfs_key k1
;
1595 btrfs_disk_key_to_cpu(&k1
, disk
);
1597 return btrfs_comp_cpu_keys(&k1
, k2
);
1601 * same as comp_keys only with two btrfs_key's
1603 int btrfs_comp_cpu_keys(struct btrfs_key
*k1
, struct btrfs_key
*k2
)
1605 if (k1
->objectid
> k2
->objectid
)
1607 if (k1
->objectid
< k2
->objectid
)
1609 if (k1
->type
> k2
->type
)
1611 if (k1
->type
< k2
->type
)
1613 if (k1
->offset
> k2
->offset
)
1615 if (k1
->offset
< k2
->offset
)
1621 * this is used by the defrag code to go through all the
1622 * leaves pointed to by a node and reallocate them so that
1623 * disk order is close to key order
1625 int btrfs_realloc_node(struct btrfs_trans_handle
*trans
,
1626 struct btrfs_root
*root
, struct extent_buffer
*parent
,
1627 int start_slot
, u64
*last_ret
,
1628 struct btrfs_key
*progress
)
1630 struct extent_buffer
*cur
;
1633 u64 search_start
= *last_ret
;
1643 int progress_passed
= 0;
1644 struct btrfs_disk_key disk_key
;
1646 parent_level
= btrfs_header_level(parent
);
1648 WARN_ON(trans
->transaction
!= root
->fs_info
->running_transaction
);
1649 WARN_ON(trans
->transid
!= root
->fs_info
->generation
);
1651 parent_nritems
= btrfs_header_nritems(parent
);
1652 blocksize
= root
->nodesize
;
1653 end_slot
= parent_nritems
;
1655 if (parent_nritems
== 1)
1658 btrfs_set_lock_blocking(parent
);
1660 for (i
= start_slot
; i
< end_slot
; i
++) {
1663 btrfs_node_key(parent
, &disk_key
, i
);
1664 if (!progress_passed
&& comp_keys(&disk_key
, progress
) < 0)
1667 progress_passed
= 1;
1668 blocknr
= btrfs_node_blockptr(parent
, i
);
1669 gen
= btrfs_node_ptr_generation(parent
, i
);
1670 if (last_block
== 0)
1671 last_block
= blocknr
;
1674 other
= btrfs_node_blockptr(parent
, i
- 1);
1675 close
= close_blocks(blocknr
, other
, blocksize
);
1677 if (!close
&& i
< end_slot
- 2) {
1678 other
= btrfs_node_blockptr(parent
, i
+ 1);
1679 close
= close_blocks(blocknr
, other
, blocksize
);
1682 last_block
= blocknr
;
1686 cur
= btrfs_find_tree_block(root
, blocknr
, blocksize
);
1688 uptodate
= btrfs_buffer_uptodate(cur
, gen
, 0);
1691 if (!cur
|| !uptodate
) {
1693 cur
= read_tree_block(root
, blocknr
, gen
);
1694 if (!cur
|| !extent_buffer_uptodate(cur
)) {
1695 free_extent_buffer(cur
);
1698 } else if (!uptodate
) {
1699 err
= btrfs_read_buffer(cur
, gen
);
1701 free_extent_buffer(cur
);
1706 if (search_start
== 0)
1707 search_start
= last_block
;
1709 btrfs_tree_lock(cur
);
1710 btrfs_set_lock_blocking(cur
);
1711 err
= __btrfs_cow_block(trans
, root
, cur
, parent
, i
,
1714 (end_slot
- i
) * blocksize
));
1716 btrfs_tree_unlock(cur
);
1717 free_extent_buffer(cur
);
1720 search_start
= cur
->start
;
1721 last_block
= cur
->start
;
1722 *last_ret
= search_start
;
1723 btrfs_tree_unlock(cur
);
1724 free_extent_buffer(cur
);
1730 * The leaf data grows from end-to-front in the node.
1731 * this returns the address of the start of the last item,
1732 * which is the stop of the leaf data stack
1734 static inline unsigned int leaf_data_end(struct btrfs_root
*root
,
1735 struct extent_buffer
*leaf
)
1737 u32 nr
= btrfs_header_nritems(leaf
);
1739 return BTRFS_LEAF_DATA_SIZE(root
);
1740 return btrfs_item_offset_nr(leaf
, nr
- 1);
1745 * search for key in the extent_buffer. The items start at offset p,
1746 * and they are item_size apart. There are 'max' items in p.
1748 * the slot in the array is returned via slot, and it points to
1749 * the place where you would insert key if it is not found in
1752 * slot may point to max if the key is bigger than all of the keys
1754 static noinline
int generic_bin_search(struct extent_buffer
*eb
,
1756 int item_size
, struct btrfs_key
*key
,
1763 struct btrfs_disk_key
*tmp
= NULL
;
1764 struct btrfs_disk_key unaligned
;
1765 unsigned long offset
;
1767 unsigned long map_start
= 0;
1768 unsigned long map_len
= 0;
1771 while (low
< high
) {
1772 mid
= (low
+ high
) / 2;
1773 offset
= p
+ mid
* item_size
;
1775 if (!kaddr
|| offset
< map_start
||
1776 (offset
+ sizeof(struct btrfs_disk_key
)) >
1777 map_start
+ map_len
) {
1779 err
= map_private_extent_buffer(eb
, offset
,
1780 sizeof(struct btrfs_disk_key
),
1781 &kaddr
, &map_start
, &map_len
);
1784 tmp
= (struct btrfs_disk_key
*)(kaddr
+ offset
-
1787 read_extent_buffer(eb
, &unaligned
,
1788 offset
, sizeof(unaligned
));
1793 tmp
= (struct btrfs_disk_key
*)(kaddr
+ offset
-
1796 ret
= comp_keys(tmp
, key
);
1812 * simple bin_search frontend that does the right thing for
1815 static int bin_search(struct extent_buffer
*eb
, struct btrfs_key
*key
,
1816 int level
, int *slot
)
1819 return generic_bin_search(eb
,
1820 offsetof(struct btrfs_leaf
, items
),
1821 sizeof(struct btrfs_item
),
1822 key
, btrfs_header_nritems(eb
),
1825 return generic_bin_search(eb
,
1826 offsetof(struct btrfs_node
, ptrs
),
1827 sizeof(struct btrfs_key_ptr
),
1828 key
, btrfs_header_nritems(eb
),
1832 int btrfs_bin_search(struct extent_buffer
*eb
, struct btrfs_key
*key
,
1833 int level
, int *slot
)
1835 return bin_search(eb
, key
, level
, slot
);
1838 static void root_add_used(struct btrfs_root
*root
, u32 size
)
1840 spin_lock(&root
->accounting_lock
);
1841 btrfs_set_root_used(&root
->root_item
,
1842 btrfs_root_used(&root
->root_item
) + size
);
1843 spin_unlock(&root
->accounting_lock
);
1846 static void root_sub_used(struct btrfs_root
*root
, u32 size
)
1848 spin_lock(&root
->accounting_lock
);
1849 btrfs_set_root_used(&root
->root_item
,
1850 btrfs_root_used(&root
->root_item
) - size
);
1851 spin_unlock(&root
->accounting_lock
);
1854 /* given a node and slot number, this reads the blocks it points to. The
1855 * extent buffer is returned with a reference taken (but unlocked).
1856 * NULL is returned on error.
1858 static noinline
struct extent_buffer
*read_node_slot(struct btrfs_root
*root
,
1859 struct extent_buffer
*parent
, int slot
)
1861 int level
= btrfs_header_level(parent
);
1862 struct extent_buffer
*eb
;
1866 if (slot
>= btrfs_header_nritems(parent
))
1871 eb
= read_tree_block(root
, btrfs_node_blockptr(parent
, slot
),
1872 btrfs_node_ptr_generation(parent
, slot
));
1873 if (eb
&& !extent_buffer_uptodate(eb
)) {
1874 free_extent_buffer(eb
);
1882 * node level balancing, used to make sure nodes are in proper order for
1883 * item deletion. We balance from the top down, so we have to make sure
1884 * that a deletion won't leave an node completely empty later on.
1886 static noinline
int balance_level(struct btrfs_trans_handle
*trans
,
1887 struct btrfs_root
*root
,
1888 struct btrfs_path
*path
, int level
)
1890 struct extent_buffer
*right
= NULL
;
1891 struct extent_buffer
*mid
;
1892 struct extent_buffer
*left
= NULL
;
1893 struct extent_buffer
*parent
= NULL
;
1897 int orig_slot
= path
->slots
[level
];
1903 mid
= path
->nodes
[level
];
1905 WARN_ON(path
->locks
[level
] != BTRFS_WRITE_LOCK
&&
1906 path
->locks
[level
] != BTRFS_WRITE_LOCK_BLOCKING
);
1907 WARN_ON(btrfs_header_generation(mid
) != trans
->transid
);
1909 orig_ptr
= btrfs_node_blockptr(mid
, orig_slot
);
1911 if (level
< BTRFS_MAX_LEVEL
- 1) {
1912 parent
= path
->nodes
[level
+ 1];
1913 pslot
= path
->slots
[level
+ 1];
1917 * deal with the case where there is only one pointer in the root
1918 * by promoting the node below to a root
1921 struct extent_buffer
*child
;
1923 if (btrfs_header_nritems(mid
) != 1)
1926 /* promote the child to a root */
1927 child
= read_node_slot(root
, mid
, 0);
1930 btrfs_std_error(root
->fs_info
, ret
);
1934 btrfs_tree_lock(child
);
1935 btrfs_set_lock_blocking(child
);
1936 ret
= btrfs_cow_block(trans
, root
, child
, mid
, 0, &child
);
1938 btrfs_tree_unlock(child
);
1939 free_extent_buffer(child
);
1943 tree_mod_log_set_root_pointer(root
, child
, 1);
1944 rcu_assign_pointer(root
->node
, child
);
1946 add_root_to_dirty_list(root
);
1947 btrfs_tree_unlock(child
);
1949 path
->locks
[level
] = 0;
1950 path
->nodes
[level
] = NULL
;
1951 clean_tree_block(trans
, root
, mid
);
1952 btrfs_tree_unlock(mid
);
1953 /* once for the path */
1954 free_extent_buffer(mid
);
1956 root_sub_used(root
, mid
->len
);
1957 btrfs_free_tree_block(trans
, root
, mid
, 0, 1);
1958 /* once for the root ptr */
1959 free_extent_buffer_stale(mid
);
1962 if (btrfs_header_nritems(mid
) >
1963 BTRFS_NODEPTRS_PER_BLOCK(root
) / 4)
1966 left
= read_node_slot(root
, parent
, pslot
- 1);
1968 btrfs_tree_lock(left
);
1969 btrfs_set_lock_blocking(left
);
1970 wret
= btrfs_cow_block(trans
, root
, left
,
1971 parent
, pslot
- 1, &left
);
1977 right
= read_node_slot(root
, parent
, pslot
+ 1);
1979 btrfs_tree_lock(right
);
1980 btrfs_set_lock_blocking(right
);
1981 wret
= btrfs_cow_block(trans
, root
, right
,
1982 parent
, pslot
+ 1, &right
);
1989 /* first, try to make some room in the middle buffer */
1991 orig_slot
+= btrfs_header_nritems(left
);
1992 wret
= push_node_left(trans
, root
, left
, mid
, 1);
1998 * then try to empty the right most buffer into the middle
2001 wret
= push_node_left(trans
, root
, mid
, right
, 1);
2002 if (wret
< 0 && wret
!= -ENOSPC
)
2004 if (btrfs_header_nritems(right
) == 0) {
2005 clean_tree_block(trans
, root
, right
);
2006 btrfs_tree_unlock(right
);
2007 del_ptr(root
, path
, level
+ 1, pslot
+ 1);
2008 root_sub_used(root
, right
->len
);
2009 btrfs_free_tree_block(trans
, root
, right
, 0, 1);
2010 free_extent_buffer_stale(right
);
2013 struct btrfs_disk_key right_key
;
2014 btrfs_node_key(right
, &right_key
, 0);
2015 tree_mod_log_set_node_key(root
->fs_info
, parent
,
2017 btrfs_set_node_key(parent
, &right_key
, pslot
+ 1);
2018 btrfs_mark_buffer_dirty(parent
);
2021 if (btrfs_header_nritems(mid
) == 1) {
2023 * we're not allowed to leave a node with one item in the
2024 * tree during a delete. A deletion from lower in the tree
2025 * could try to delete the only pointer in this node.
2026 * So, pull some keys from the left.
2027 * There has to be a left pointer at this point because
2028 * otherwise we would have pulled some pointers from the
2033 btrfs_std_error(root
->fs_info
, ret
);
2036 wret
= balance_node_right(trans
, root
, mid
, left
);
2042 wret
= push_node_left(trans
, root
, left
, mid
, 1);
2048 if (btrfs_header_nritems(mid
) == 0) {
2049 clean_tree_block(trans
, root
, mid
);
2050 btrfs_tree_unlock(mid
);
2051 del_ptr(root
, path
, level
+ 1, pslot
);
2052 root_sub_used(root
, mid
->len
);
2053 btrfs_free_tree_block(trans
, root
, mid
, 0, 1);
2054 free_extent_buffer_stale(mid
);
2057 /* update the parent key to reflect our changes */
2058 struct btrfs_disk_key mid_key
;
2059 btrfs_node_key(mid
, &mid_key
, 0);
2060 tree_mod_log_set_node_key(root
->fs_info
, parent
,
2062 btrfs_set_node_key(parent
, &mid_key
, pslot
);
2063 btrfs_mark_buffer_dirty(parent
);
2066 /* update the path */
2068 if (btrfs_header_nritems(left
) > orig_slot
) {
2069 extent_buffer_get(left
);
2070 /* left was locked after cow */
2071 path
->nodes
[level
] = left
;
2072 path
->slots
[level
+ 1] -= 1;
2073 path
->slots
[level
] = orig_slot
;
2075 btrfs_tree_unlock(mid
);
2076 free_extent_buffer(mid
);
2079 orig_slot
-= btrfs_header_nritems(left
);
2080 path
->slots
[level
] = orig_slot
;
2083 /* double check we haven't messed things up */
2085 btrfs_node_blockptr(path
->nodes
[level
], path
->slots
[level
]))
2089 btrfs_tree_unlock(right
);
2090 free_extent_buffer(right
);
2093 if (path
->nodes
[level
] != left
)
2094 btrfs_tree_unlock(left
);
2095 free_extent_buffer(left
);
2100 /* Node balancing for insertion. Here we only split or push nodes around
2101 * when they are completely full. This is also done top down, so we
2102 * have to be pessimistic.
2104 static noinline
int push_nodes_for_insert(struct btrfs_trans_handle
*trans
,
2105 struct btrfs_root
*root
,
2106 struct btrfs_path
*path
, int level
)
2108 struct extent_buffer
*right
= NULL
;
2109 struct extent_buffer
*mid
;
2110 struct extent_buffer
*left
= NULL
;
2111 struct extent_buffer
*parent
= NULL
;
2115 int orig_slot
= path
->slots
[level
];
2120 mid
= path
->nodes
[level
];
2121 WARN_ON(btrfs_header_generation(mid
) != trans
->transid
);
2123 if (level
< BTRFS_MAX_LEVEL
- 1) {
2124 parent
= path
->nodes
[level
+ 1];
2125 pslot
= path
->slots
[level
+ 1];
2131 left
= read_node_slot(root
, parent
, pslot
- 1);
2133 /* first, try to make some room in the middle buffer */
2137 btrfs_tree_lock(left
);
2138 btrfs_set_lock_blocking(left
);
2140 left_nr
= btrfs_header_nritems(left
);
2141 if (left_nr
>= BTRFS_NODEPTRS_PER_BLOCK(root
) - 1) {
2144 ret
= btrfs_cow_block(trans
, root
, left
, parent
,
2149 wret
= push_node_left(trans
, root
,
2156 struct btrfs_disk_key disk_key
;
2157 orig_slot
+= left_nr
;
2158 btrfs_node_key(mid
, &disk_key
, 0);
2159 tree_mod_log_set_node_key(root
->fs_info
, parent
,
2161 btrfs_set_node_key(parent
, &disk_key
, pslot
);
2162 btrfs_mark_buffer_dirty(parent
);
2163 if (btrfs_header_nritems(left
) > orig_slot
) {
2164 path
->nodes
[level
] = left
;
2165 path
->slots
[level
+ 1] -= 1;
2166 path
->slots
[level
] = orig_slot
;
2167 btrfs_tree_unlock(mid
);
2168 free_extent_buffer(mid
);
2171 btrfs_header_nritems(left
);
2172 path
->slots
[level
] = orig_slot
;
2173 btrfs_tree_unlock(left
);
2174 free_extent_buffer(left
);
2178 btrfs_tree_unlock(left
);
2179 free_extent_buffer(left
);
2181 right
= read_node_slot(root
, parent
, pslot
+ 1);
2184 * then try to empty the right most buffer into the middle
2189 btrfs_tree_lock(right
);
2190 btrfs_set_lock_blocking(right
);
2192 right_nr
= btrfs_header_nritems(right
);
2193 if (right_nr
>= BTRFS_NODEPTRS_PER_BLOCK(root
) - 1) {
2196 ret
= btrfs_cow_block(trans
, root
, right
,
2202 wret
= balance_node_right(trans
, root
,
2209 struct btrfs_disk_key disk_key
;
2211 btrfs_node_key(right
, &disk_key
, 0);
2212 tree_mod_log_set_node_key(root
->fs_info
, parent
,
2214 btrfs_set_node_key(parent
, &disk_key
, pslot
+ 1);
2215 btrfs_mark_buffer_dirty(parent
);
2217 if (btrfs_header_nritems(mid
) <= orig_slot
) {
2218 path
->nodes
[level
] = right
;
2219 path
->slots
[level
+ 1] += 1;
2220 path
->slots
[level
] = orig_slot
-
2221 btrfs_header_nritems(mid
);
2222 btrfs_tree_unlock(mid
);
2223 free_extent_buffer(mid
);
2225 btrfs_tree_unlock(right
);
2226 free_extent_buffer(right
);
2230 btrfs_tree_unlock(right
);
2231 free_extent_buffer(right
);
2237 * readahead one full node of leaves, finding things that are close
2238 * to the block in 'slot', and triggering ra on them.
2240 static void reada_for_search(struct btrfs_root
*root
,
2241 struct btrfs_path
*path
,
2242 int level
, int slot
, u64 objectid
)
2244 struct extent_buffer
*node
;
2245 struct btrfs_disk_key disk_key
;
2251 int direction
= path
->reada
;
2252 struct extent_buffer
*eb
;
2260 if (!path
->nodes
[level
])
2263 node
= path
->nodes
[level
];
2265 search
= btrfs_node_blockptr(node
, slot
);
2266 blocksize
= root
->nodesize
;
2267 eb
= btrfs_find_tree_block(root
, search
, blocksize
);
2269 free_extent_buffer(eb
);
2275 nritems
= btrfs_header_nritems(node
);
2279 if (direction
< 0) {
2283 } else if (direction
> 0) {
2288 if (path
->reada
< 0 && objectid
) {
2289 btrfs_node_key(node
, &disk_key
, nr
);
2290 if (btrfs_disk_key_objectid(&disk_key
) != objectid
)
2293 search
= btrfs_node_blockptr(node
, nr
);
2294 if ((search
<= target
&& target
- search
<= 65536) ||
2295 (search
> target
&& search
- target
<= 65536)) {
2296 gen
= btrfs_node_ptr_generation(node
, nr
);
2297 readahead_tree_block(root
, search
, blocksize
);
2301 if ((nread
> 65536 || nscan
> 32))
2306 static noinline
void reada_for_balance(struct btrfs_root
*root
,
2307 struct btrfs_path
*path
, int level
)
2311 struct extent_buffer
*parent
;
2312 struct extent_buffer
*eb
;
2318 parent
= path
->nodes
[level
+ 1];
2322 nritems
= btrfs_header_nritems(parent
);
2323 slot
= path
->slots
[level
+ 1];
2324 blocksize
= root
->nodesize
;
2327 block1
= btrfs_node_blockptr(parent
, slot
- 1);
2328 gen
= btrfs_node_ptr_generation(parent
, slot
- 1);
2329 eb
= btrfs_find_tree_block(root
, block1
, blocksize
);
2331 * if we get -eagain from btrfs_buffer_uptodate, we
2332 * don't want to return eagain here. That will loop
2335 if (eb
&& btrfs_buffer_uptodate(eb
, gen
, 1) != 0)
2337 free_extent_buffer(eb
);
2339 if (slot
+ 1 < nritems
) {
2340 block2
= btrfs_node_blockptr(parent
, slot
+ 1);
2341 gen
= btrfs_node_ptr_generation(parent
, slot
+ 1);
2342 eb
= btrfs_find_tree_block(root
, block2
, blocksize
);
2343 if (eb
&& btrfs_buffer_uptodate(eb
, gen
, 1) != 0)
2345 free_extent_buffer(eb
);
2349 readahead_tree_block(root
, block1
, blocksize
);
2351 readahead_tree_block(root
, block2
, blocksize
);
2356 * when we walk down the tree, it is usually safe to unlock the higher layers
2357 * in the tree. The exceptions are when our path goes through slot 0, because
2358 * operations on the tree might require changing key pointers higher up in the
2361 * callers might also have set path->keep_locks, which tells this code to keep
2362 * the lock if the path points to the last slot in the block. This is part of
2363 * walking through the tree, and selecting the next slot in the higher block.
2365 * lowest_unlock sets the lowest level in the tree we're allowed to unlock. so
2366 * if lowest_unlock is 1, level 0 won't be unlocked
2368 static noinline
void unlock_up(struct btrfs_path
*path
, int level
,
2369 int lowest_unlock
, int min_write_lock_level
,
2370 int *write_lock_level
)
2373 int skip_level
= level
;
2375 struct extent_buffer
*t
;
2377 for (i
= level
; i
< BTRFS_MAX_LEVEL
; i
++) {
2378 if (!path
->nodes
[i
])
2380 if (!path
->locks
[i
])
2382 if (!no_skips
&& path
->slots
[i
] == 0) {
2386 if (!no_skips
&& path
->keep_locks
) {
2389 nritems
= btrfs_header_nritems(t
);
2390 if (nritems
< 1 || path
->slots
[i
] >= nritems
- 1) {
2395 if (skip_level
< i
&& i
>= lowest_unlock
)
2399 if (i
>= lowest_unlock
&& i
> skip_level
&& path
->locks
[i
]) {
2400 btrfs_tree_unlock_rw(t
, path
->locks
[i
]);
2402 if (write_lock_level
&&
2403 i
> min_write_lock_level
&&
2404 i
<= *write_lock_level
) {
2405 *write_lock_level
= i
- 1;
2412 * This releases any locks held in the path starting at level and
2413 * going all the way up to the root.
2415 * btrfs_search_slot will keep the lock held on higher nodes in a few
2416 * corner cases, such as COW of the block at slot zero in the node. This
2417 * ignores those rules, and it should only be called when there are no
2418 * more updates to be done higher up in the tree.
2420 noinline
void btrfs_unlock_up_safe(struct btrfs_path
*path
, int level
)
2424 if (path
->keep_locks
)
2427 for (i
= level
; i
< BTRFS_MAX_LEVEL
; i
++) {
2428 if (!path
->nodes
[i
])
2430 if (!path
->locks
[i
])
2432 btrfs_tree_unlock_rw(path
->nodes
[i
], path
->locks
[i
]);
2438 * helper function for btrfs_search_slot. The goal is to find a block
2439 * in cache without setting the path to blocking. If we find the block
2440 * we return zero and the path is unchanged.
2442 * If we can't find the block, we set the path blocking and do some
2443 * reada. -EAGAIN is returned and the search must be repeated.
2446 read_block_for_search(struct btrfs_trans_handle
*trans
,
2447 struct btrfs_root
*root
, struct btrfs_path
*p
,
2448 struct extent_buffer
**eb_ret
, int level
, int slot
,
2449 struct btrfs_key
*key
, u64 time_seq
)
2454 struct extent_buffer
*b
= *eb_ret
;
2455 struct extent_buffer
*tmp
;
2458 blocknr
= btrfs_node_blockptr(b
, slot
);
2459 gen
= btrfs_node_ptr_generation(b
, slot
);
2460 blocksize
= root
->nodesize
;
2462 tmp
= btrfs_find_tree_block(root
, blocknr
, blocksize
);
2464 /* first we do an atomic uptodate check */
2465 if (btrfs_buffer_uptodate(tmp
, gen
, 1) > 0) {
2470 /* the pages were up to date, but we failed
2471 * the generation number check. Do a full
2472 * read for the generation number that is correct.
2473 * We must do this without dropping locks so
2474 * we can trust our generation number
2476 btrfs_set_path_blocking(p
);
2478 /* now we're allowed to do a blocking uptodate check */
2479 ret
= btrfs_read_buffer(tmp
, gen
);
2484 free_extent_buffer(tmp
);
2485 btrfs_release_path(p
);
2490 * reduce lock contention at high levels
2491 * of the btree by dropping locks before
2492 * we read. Don't release the lock on the current
2493 * level because we need to walk this node to figure
2494 * out which blocks to read.
2496 btrfs_unlock_up_safe(p
, level
+ 1);
2497 btrfs_set_path_blocking(p
);
2499 free_extent_buffer(tmp
);
2501 reada_for_search(root
, p
, level
, slot
, key
->objectid
);
2503 btrfs_release_path(p
);
2506 tmp
= read_tree_block(root
, blocknr
, 0);
2509 * If the read above didn't mark this buffer up to date,
2510 * it will never end up being up to date. Set ret to EIO now
2511 * and give up so that our caller doesn't loop forever
2514 if (!btrfs_buffer_uptodate(tmp
, 0, 0))
2516 free_extent_buffer(tmp
);
2522 * helper function for btrfs_search_slot. This does all of the checks
2523 * for node-level blocks and does any balancing required based on
2526 * If no extra work was required, zero is returned. If we had to
2527 * drop the path, -EAGAIN is returned and btrfs_search_slot must
2531 setup_nodes_for_search(struct btrfs_trans_handle
*trans
,
2532 struct btrfs_root
*root
, struct btrfs_path
*p
,
2533 struct extent_buffer
*b
, int level
, int ins_len
,
2534 int *write_lock_level
)
2537 if ((p
->search_for_split
|| ins_len
> 0) && btrfs_header_nritems(b
) >=
2538 BTRFS_NODEPTRS_PER_BLOCK(root
) - 3) {
2541 if (*write_lock_level
< level
+ 1) {
2542 *write_lock_level
= level
+ 1;
2543 btrfs_release_path(p
);
2547 btrfs_set_path_blocking(p
);
2548 reada_for_balance(root
, p
, level
);
2549 sret
= split_node(trans
, root
, p
, level
);
2550 btrfs_clear_path_blocking(p
, NULL
, 0);
2557 b
= p
->nodes
[level
];
2558 } else if (ins_len
< 0 && btrfs_header_nritems(b
) <
2559 BTRFS_NODEPTRS_PER_BLOCK(root
) / 2) {
2562 if (*write_lock_level
< level
+ 1) {
2563 *write_lock_level
= level
+ 1;
2564 btrfs_release_path(p
);
2568 btrfs_set_path_blocking(p
);
2569 reada_for_balance(root
, p
, level
);
2570 sret
= balance_level(trans
, root
, p
, level
);
2571 btrfs_clear_path_blocking(p
, NULL
, 0);
2577 b
= p
->nodes
[level
];
2579 btrfs_release_path(p
);
2582 BUG_ON(btrfs_header_nritems(b
) == 1);
2592 static void key_search_validate(struct extent_buffer
*b
,
2593 struct btrfs_key
*key
,
2596 #ifdef CONFIG_BTRFS_ASSERT
2597 struct btrfs_disk_key disk_key
;
2599 btrfs_cpu_key_to_disk(&disk_key
, key
);
2602 ASSERT(!memcmp_extent_buffer(b
, &disk_key
,
2603 offsetof(struct btrfs_leaf
, items
[0].key
),
2606 ASSERT(!memcmp_extent_buffer(b
, &disk_key
,
2607 offsetof(struct btrfs_node
, ptrs
[0].key
),
2612 static int key_search(struct extent_buffer
*b
, struct btrfs_key
*key
,
2613 int level
, int *prev_cmp
, int *slot
)
2615 if (*prev_cmp
!= 0) {
2616 *prev_cmp
= bin_search(b
, key
, level
, slot
);
2620 key_search_validate(b
, key
, level
);
2626 int btrfs_find_item(struct btrfs_root
*fs_root
, struct btrfs_path
*found_path
,
2627 u64 iobjectid
, u64 ioff
, u8 key_type
,
2628 struct btrfs_key
*found_key
)
2631 struct btrfs_key key
;
2632 struct extent_buffer
*eb
;
2633 struct btrfs_path
*path
;
2635 key
.type
= key_type
;
2636 key
.objectid
= iobjectid
;
2639 if (found_path
== NULL
) {
2640 path
= btrfs_alloc_path();
2646 ret
= btrfs_search_slot(NULL
, fs_root
, &key
, path
, 0, 0);
2647 if ((ret
< 0) || (found_key
== NULL
)) {
2648 if (path
!= found_path
)
2649 btrfs_free_path(path
);
2653 eb
= path
->nodes
[0];
2654 if (ret
&& path
->slots
[0] >= btrfs_header_nritems(eb
)) {
2655 ret
= btrfs_next_leaf(fs_root
, path
);
2658 eb
= path
->nodes
[0];
2661 btrfs_item_key_to_cpu(eb
, found_key
, path
->slots
[0]);
2662 if (found_key
->type
!= key
.type
||
2663 found_key
->objectid
!= key
.objectid
)
2670 * look for key in the tree. path is filled in with nodes along the way
2671 * if key is found, we return zero and you can find the item in the leaf
2672 * level of the path (level 0)
2674 * If the key isn't found, the path points to the slot where it should
2675 * be inserted, and 1 is returned. If there are other errors during the
2676 * search a negative error number is returned.
2678 * if ins_len > 0, nodes and leaves will be split as we walk down the
2679 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
2682 int btrfs_search_slot(struct btrfs_trans_handle
*trans
, struct btrfs_root
2683 *root
, struct btrfs_key
*key
, struct btrfs_path
*p
, int
2686 struct extent_buffer
*b
;
2691 int lowest_unlock
= 1;
2693 /* everything at write_lock_level or lower must be write locked */
2694 int write_lock_level
= 0;
2695 u8 lowest_level
= 0;
2696 int min_write_lock_level
;
2699 lowest_level
= p
->lowest_level
;
2700 WARN_ON(lowest_level
&& ins_len
> 0);
2701 WARN_ON(p
->nodes
[0] != NULL
);
2702 BUG_ON(!cow
&& ins_len
);
2707 /* when we are removing items, we might have to go up to level
2708 * two as we update tree pointers Make sure we keep write
2709 * for those levels as well
2711 write_lock_level
= 2;
2712 } else if (ins_len
> 0) {
2714 * for inserting items, make sure we have a write lock on
2715 * level 1 so we can update keys
2717 write_lock_level
= 1;
2721 write_lock_level
= -1;
2723 if (cow
&& (p
->keep_locks
|| p
->lowest_level
))
2724 write_lock_level
= BTRFS_MAX_LEVEL
;
2726 min_write_lock_level
= write_lock_level
;
2731 * we try very hard to do read locks on the root
2733 root_lock
= BTRFS_READ_LOCK
;
2735 if (p
->search_commit_root
) {
2737 * the commit roots are read only
2738 * so we always do read locks
2740 if (p
->need_commit_sem
)
2741 down_read(&root
->fs_info
->commit_root_sem
);
2742 b
= root
->commit_root
;
2743 extent_buffer_get(b
);
2744 level
= btrfs_header_level(b
);
2745 if (p
->need_commit_sem
)
2746 up_read(&root
->fs_info
->commit_root_sem
);
2747 if (!p
->skip_locking
)
2748 btrfs_tree_read_lock(b
);
2750 if (p
->skip_locking
) {
2751 b
= btrfs_root_node(root
);
2752 level
= btrfs_header_level(b
);
2754 /* we don't know the level of the root node
2755 * until we actually have it read locked
2757 b
= btrfs_read_lock_root_node(root
);
2758 level
= btrfs_header_level(b
);
2759 if (level
<= write_lock_level
) {
2760 /* whoops, must trade for write lock */
2761 btrfs_tree_read_unlock(b
);
2762 free_extent_buffer(b
);
2763 b
= btrfs_lock_root_node(root
);
2764 root_lock
= BTRFS_WRITE_LOCK
;
2766 /* the level might have changed, check again */
2767 level
= btrfs_header_level(b
);
2771 p
->nodes
[level
] = b
;
2772 if (!p
->skip_locking
)
2773 p
->locks
[level
] = root_lock
;
2776 level
= btrfs_header_level(b
);
2779 * setup the path here so we can release it under lock
2780 * contention with the cow code
2784 * if we don't really need to cow this block
2785 * then we don't want to set the path blocking,
2786 * so we test it here
2788 if (!should_cow_block(trans
, root
, b
))
2792 * must have write locks on this node and the
2795 if (level
> write_lock_level
||
2796 (level
+ 1 > write_lock_level
&&
2797 level
+ 1 < BTRFS_MAX_LEVEL
&&
2798 p
->nodes
[level
+ 1])) {
2799 write_lock_level
= level
+ 1;
2800 btrfs_release_path(p
);
2804 btrfs_set_path_blocking(p
);
2805 err
= btrfs_cow_block(trans
, root
, b
,
2806 p
->nodes
[level
+ 1],
2807 p
->slots
[level
+ 1], &b
);
2814 p
->nodes
[level
] = b
;
2815 btrfs_clear_path_blocking(p
, NULL
, 0);
2818 * we have a lock on b and as long as we aren't changing
2819 * the tree, there is no way to for the items in b to change.
2820 * It is safe to drop the lock on our parent before we
2821 * go through the expensive btree search on b.
2823 * If we're inserting or deleting (ins_len != 0), then we might
2824 * be changing slot zero, which may require changing the parent.
2825 * So, we can't drop the lock until after we know which slot
2826 * we're operating on.
2828 if (!ins_len
&& !p
->keep_locks
) {
2831 if (u
< BTRFS_MAX_LEVEL
&& p
->locks
[u
]) {
2832 btrfs_tree_unlock_rw(p
->nodes
[u
], p
->locks
[u
]);
2837 ret
= key_search(b
, key
, level
, &prev_cmp
, &slot
);
2841 if (ret
&& slot
> 0) {
2845 p
->slots
[level
] = slot
;
2846 err
= setup_nodes_for_search(trans
, root
, p
, b
, level
,
2847 ins_len
, &write_lock_level
);
2854 b
= p
->nodes
[level
];
2855 slot
= p
->slots
[level
];
2858 * slot 0 is special, if we change the key
2859 * we have to update the parent pointer
2860 * which means we must have a write lock
2863 if (slot
== 0 && ins_len
&&
2864 write_lock_level
< level
+ 1) {
2865 write_lock_level
= level
+ 1;
2866 btrfs_release_path(p
);
2870 unlock_up(p
, level
, lowest_unlock
,
2871 min_write_lock_level
, &write_lock_level
);
2873 if (level
== lowest_level
) {
2879 err
= read_block_for_search(trans
, root
, p
,
2880 &b
, level
, slot
, key
, 0);
2888 if (!p
->skip_locking
) {
2889 level
= btrfs_header_level(b
);
2890 if (level
<= write_lock_level
) {
2891 err
= btrfs_try_tree_write_lock(b
);
2893 btrfs_set_path_blocking(p
);
2895 btrfs_clear_path_blocking(p
, b
,
2898 p
->locks
[level
] = BTRFS_WRITE_LOCK
;
2900 err
= btrfs_try_tree_read_lock(b
);
2902 btrfs_set_path_blocking(p
);
2903 btrfs_tree_read_lock(b
);
2904 btrfs_clear_path_blocking(p
, b
,
2907 p
->locks
[level
] = BTRFS_READ_LOCK
;
2909 p
->nodes
[level
] = b
;
2912 p
->slots
[level
] = slot
;
2914 btrfs_leaf_free_space(root
, b
) < ins_len
) {
2915 if (write_lock_level
< 1) {
2916 write_lock_level
= 1;
2917 btrfs_release_path(p
);
2921 btrfs_set_path_blocking(p
);
2922 err
= split_leaf(trans
, root
, key
,
2923 p
, ins_len
, ret
== 0);
2924 btrfs_clear_path_blocking(p
, NULL
, 0);
2932 if (!p
->search_for_split
)
2933 unlock_up(p
, level
, lowest_unlock
,
2934 min_write_lock_level
, &write_lock_level
);
2941 * we don't really know what they plan on doing with the path
2942 * from here on, so for now just mark it as blocking
2944 if (!p
->leave_spinning
)
2945 btrfs_set_path_blocking(p
);
2947 btrfs_release_path(p
);
2952 * Like btrfs_search_slot, this looks for a key in the given tree. It uses the
2953 * current state of the tree together with the operations recorded in the tree
2954 * modification log to search for the key in a previous version of this tree, as
2955 * denoted by the time_seq parameter.
2957 * Naturally, there is no support for insert, delete or cow operations.
2959 * The resulting path and return value will be set up as if we called
2960 * btrfs_search_slot at that point in time with ins_len and cow both set to 0.
2962 int btrfs_search_old_slot(struct btrfs_root
*root
, struct btrfs_key
*key
,
2963 struct btrfs_path
*p
, u64 time_seq
)
2965 struct extent_buffer
*b
;
2970 int lowest_unlock
= 1;
2971 u8 lowest_level
= 0;
2974 lowest_level
= p
->lowest_level
;
2975 WARN_ON(p
->nodes
[0] != NULL
);
2977 if (p
->search_commit_root
) {
2979 return btrfs_search_slot(NULL
, root
, key
, p
, 0, 0);
2983 b
= get_old_root(root
, time_seq
);
2984 level
= btrfs_header_level(b
);
2985 p
->locks
[level
] = BTRFS_READ_LOCK
;
2988 level
= btrfs_header_level(b
);
2989 p
->nodes
[level
] = b
;
2990 btrfs_clear_path_blocking(p
, NULL
, 0);
2993 * we have a lock on b and as long as we aren't changing
2994 * the tree, there is no way to for the items in b to change.
2995 * It is safe to drop the lock on our parent before we
2996 * go through the expensive btree search on b.
2998 btrfs_unlock_up_safe(p
, level
+ 1);
3001 * Since we can unwind eb's we want to do a real search every
3005 ret
= key_search(b
, key
, level
, &prev_cmp
, &slot
);
3009 if (ret
&& slot
> 0) {
3013 p
->slots
[level
] = slot
;
3014 unlock_up(p
, level
, lowest_unlock
, 0, NULL
);
3016 if (level
== lowest_level
) {
3022 err
= read_block_for_search(NULL
, root
, p
, &b
, level
,
3023 slot
, key
, time_seq
);
3031 level
= btrfs_header_level(b
);
3032 err
= btrfs_try_tree_read_lock(b
);
3034 btrfs_set_path_blocking(p
);
3035 btrfs_tree_read_lock(b
);
3036 btrfs_clear_path_blocking(p
, b
,
3039 b
= tree_mod_log_rewind(root
->fs_info
, p
, b
, time_seq
);
3044 p
->locks
[level
] = BTRFS_READ_LOCK
;
3045 p
->nodes
[level
] = b
;
3047 p
->slots
[level
] = slot
;
3048 unlock_up(p
, level
, lowest_unlock
, 0, NULL
);
3054 if (!p
->leave_spinning
)
3055 btrfs_set_path_blocking(p
);
3057 btrfs_release_path(p
);
3063 * helper to use instead of search slot if no exact match is needed but
3064 * instead the next or previous item should be returned.
3065 * When find_higher is true, the next higher item is returned, the next lower
3067 * When return_any and find_higher are both true, and no higher item is found,
3068 * return the next lower instead.
3069 * When return_any is true and find_higher is false, and no lower item is found,
3070 * return the next higher instead.
3071 * It returns 0 if any item is found, 1 if none is found (tree empty), and
3074 int btrfs_search_slot_for_read(struct btrfs_root
*root
,
3075 struct btrfs_key
*key
, struct btrfs_path
*p
,
3076 int find_higher
, int return_any
)
3079 struct extent_buffer
*leaf
;
3082 ret
= btrfs_search_slot(NULL
, root
, key
, p
, 0, 0);
3086 * a return value of 1 means the path is at the position where the
3087 * item should be inserted. Normally this is the next bigger item,
3088 * but in case the previous item is the last in a leaf, path points
3089 * to the first free slot in the previous leaf, i.e. at an invalid
3095 if (p
->slots
[0] >= btrfs_header_nritems(leaf
)) {
3096 ret
= btrfs_next_leaf(root
, p
);
3102 * no higher item found, return the next
3107 btrfs_release_path(p
);
3111 if (p
->slots
[0] == 0) {
3112 ret
= btrfs_prev_leaf(root
, p
);
3117 if (p
->slots
[0] == btrfs_header_nritems(leaf
))
3124 * no lower item found, return the next
3129 btrfs_release_path(p
);
3139 * adjust the pointers going up the tree, starting at level
3140 * making sure the right key of each node is points to 'key'.
3141 * This is used after shifting pointers to the left, so it stops
3142 * fixing up pointers when a given leaf/node is not in slot 0 of the
3146 static void fixup_low_keys(struct btrfs_root
*root
, struct btrfs_path
*path
,
3147 struct btrfs_disk_key
*key
, int level
)
3150 struct extent_buffer
*t
;
3152 for (i
= level
; i
< BTRFS_MAX_LEVEL
; i
++) {
3153 int tslot
= path
->slots
[i
];
3154 if (!path
->nodes
[i
])
3157 tree_mod_log_set_node_key(root
->fs_info
, t
, tslot
, 1);
3158 btrfs_set_node_key(t
, key
, tslot
);
3159 btrfs_mark_buffer_dirty(path
->nodes
[i
]);
3168 * This function isn't completely safe. It's the caller's responsibility
3169 * that the new key won't break the order
3171 void btrfs_set_item_key_safe(struct btrfs_root
*root
, struct btrfs_path
*path
,
3172 struct btrfs_key
*new_key
)
3174 struct btrfs_disk_key disk_key
;
3175 struct extent_buffer
*eb
;
3178 eb
= path
->nodes
[0];
3179 slot
= path
->slots
[0];
3181 btrfs_item_key(eb
, &disk_key
, slot
- 1);
3182 BUG_ON(comp_keys(&disk_key
, new_key
) >= 0);
3184 if (slot
< btrfs_header_nritems(eb
) - 1) {
3185 btrfs_item_key(eb
, &disk_key
, slot
+ 1);
3186 BUG_ON(comp_keys(&disk_key
, new_key
) <= 0);
3189 btrfs_cpu_key_to_disk(&disk_key
, new_key
);
3190 btrfs_set_item_key(eb
, &disk_key
, slot
);
3191 btrfs_mark_buffer_dirty(eb
);
3193 fixup_low_keys(root
, path
, &disk_key
, 1);
3197 * try to push data from one node into the next node left in the
3200 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
3201 * error, and > 0 if there was no room in the left hand block.
3203 static int push_node_left(struct btrfs_trans_handle
*trans
,
3204 struct btrfs_root
*root
, struct extent_buffer
*dst
,
3205 struct extent_buffer
*src
, int empty
)
3212 src_nritems
= btrfs_header_nritems(src
);
3213 dst_nritems
= btrfs_header_nritems(dst
);
3214 push_items
= BTRFS_NODEPTRS_PER_BLOCK(root
) - dst_nritems
;
3215 WARN_ON(btrfs_header_generation(src
) != trans
->transid
);
3216 WARN_ON(btrfs_header_generation(dst
) != trans
->transid
);
3218 if (!empty
&& src_nritems
<= 8)
3221 if (push_items
<= 0)
3225 push_items
= min(src_nritems
, push_items
);
3226 if (push_items
< src_nritems
) {
3227 /* leave at least 8 pointers in the node if
3228 * we aren't going to empty it
3230 if (src_nritems
- push_items
< 8) {
3231 if (push_items
<= 8)
3237 push_items
= min(src_nritems
- 8, push_items
);
3239 ret
= tree_mod_log_eb_copy(root
->fs_info
, dst
, src
, dst_nritems
, 0,
3242 btrfs_abort_transaction(trans
, root
, ret
);
3245 copy_extent_buffer(dst
, src
,
3246 btrfs_node_key_ptr_offset(dst_nritems
),
3247 btrfs_node_key_ptr_offset(0),
3248 push_items
* sizeof(struct btrfs_key_ptr
));
3250 if (push_items
< src_nritems
) {
3252 * don't call tree_mod_log_eb_move here, key removal was already
3253 * fully logged by tree_mod_log_eb_copy above.
3255 memmove_extent_buffer(src
, btrfs_node_key_ptr_offset(0),
3256 btrfs_node_key_ptr_offset(push_items
),
3257 (src_nritems
- push_items
) *
3258 sizeof(struct btrfs_key_ptr
));
3260 btrfs_set_header_nritems(src
, src_nritems
- push_items
);
3261 btrfs_set_header_nritems(dst
, dst_nritems
+ push_items
);
3262 btrfs_mark_buffer_dirty(src
);
3263 btrfs_mark_buffer_dirty(dst
);
3269 * try to push data from one node into the next node right in the
3272 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
3273 * error, and > 0 if there was no room in the right hand block.
3275 * this will only push up to 1/2 the contents of the left node over
3277 static int balance_node_right(struct btrfs_trans_handle
*trans
,
3278 struct btrfs_root
*root
,
3279 struct extent_buffer
*dst
,
3280 struct extent_buffer
*src
)
3288 WARN_ON(btrfs_header_generation(src
) != trans
->transid
);
3289 WARN_ON(btrfs_header_generation(dst
) != trans
->transid
);
3291 src_nritems
= btrfs_header_nritems(src
);
3292 dst_nritems
= btrfs_header_nritems(dst
);
3293 push_items
= BTRFS_NODEPTRS_PER_BLOCK(root
) - dst_nritems
;
3294 if (push_items
<= 0)
3297 if (src_nritems
< 4)
3300 max_push
= src_nritems
/ 2 + 1;
3301 /* don't try to empty the node */
3302 if (max_push
>= src_nritems
)
3305 if (max_push
< push_items
)
3306 push_items
= max_push
;
3308 tree_mod_log_eb_move(root
->fs_info
, dst
, push_items
, 0, dst_nritems
);
3309 memmove_extent_buffer(dst
, btrfs_node_key_ptr_offset(push_items
),
3310 btrfs_node_key_ptr_offset(0),
3312 sizeof(struct btrfs_key_ptr
));
3314 ret
= tree_mod_log_eb_copy(root
->fs_info
, dst
, src
, 0,
3315 src_nritems
- push_items
, push_items
);
3317 btrfs_abort_transaction(trans
, root
, ret
);
3320 copy_extent_buffer(dst
, src
,
3321 btrfs_node_key_ptr_offset(0),
3322 btrfs_node_key_ptr_offset(src_nritems
- push_items
),
3323 push_items
* sizeof(struct btrfs_key_ptr
));
3325 btrfs_set_header_nritems(src
, src_nritems
- push_items
);
3326 btrfs_set_header_nritems(dst
, dst_nritems
+ push_items
);
3328 btrfs_mark_buffer_dirty(src
);
3329 btrfs_mark_buffer_dirty(dst
);
3335 * helper function to insert a new root level in the tree.
3336 * A new node is allocated, and a single item is inserted to
3337 * point to the existing root
3339 * returns zero on success or < 0 on failure.
3341 static noinline
int insert_new_root(struct btrfs_trans_handle
*trans
,
3342 struct btrfs_root
*root
,
3343 struct btrfs_path
*path
, int level
)
3346 struct extent_buffer
*lower
;
3347 struct extent_buffer
*c
;
3348 struct extent_buffer
*old
;
3349 struct btrfs_disk_key lower_key
;
3351 BUG_ON(path
->nodes
[level
]);
3352 BUG_ON(path
->nodes
[level
-1] != root
->node
);
3354 lower
= path
->nodes
[level
-1];
3356 btrfs_item_key(lower
, &lower_key
, 0);
3358 btrfs_node_key(lower
, &lower_key
, 0);
3360 c
= btrfs_alloc_free_block(trans
, root
, root
->nodesize
, 0,
3361 root
->root_key
.objectid
, &lower_key
,
3362 level
, root
->node
->start
, 0);
3366 root_add_used(root
, root
->nodesize
);
3368 memset_extent_buffer(c
, 0, 0, sizeof(struct btrfs_header
));
3369 btrfs_set_header_nritems(c
, 1);
3370 btrfs_set_header_level(c
, level
);
3371 btrfs_set_header_bytenr(c
, c
->start
);
3372 btrfs_set_header_generation(c
, trans
->transid
);
3373 btrfs_set_header_backref_rev(c
, BTRFS_MIXED_BACKREF_REV
);
3374 btrfs_set_header_owner(c
, root
->root_key
.objectid
);
3376 write_extent_buffer(c
, root
->fs_info
->fsid
, btrfs_header_fsid(),
3379 write_extent_buffer(c
, root
->fs_info
->chunk_tree_uuid
,
3380 btrfs_header_chunk_tree_uuid(c
), BTRFS_UUID_SIZE
);
3382 btrfs_set_node_key(c
, &lower_key
, 0);
3383 btrfs_set_node_blockptr(c
, 0, lower
->start
);
3384 lower_gen
= btrfs_header_generation(lower
);
3385 WARN_ON(lower_gen
!= trans
->transid
);
3387 btrfs_set_node_ptr_generation(c
, 0, lower_gen
);
3389 btrfs_mark_buffer_dirty(c
);
3392 tree_mod_log_set_root_pointer(root
, c
, 0);
3393 rcu_assign_pointer(root
->node
, c
);
3395 /* the super has an extra ref to root->node */
3396 free_extent_buffer(old
);
3398 add_root_to_dirty_list(root
);
3399 extent_buffer_get(c
);
3400 path
->nodes
[level
] = c
;
3401 path
->locks
[level
] = BTRFS_WRITE_LOCK
;
3402 path
->slots
[level
] = 0;
3407 * worker function to insert a single pointer in a node.
3408 * the node should have enough room for the pointer already
3410 * slot and level indicate where you want the key to go, and
3411 * blocknr is the block the key points to.
3413 static void insert_ptr(struct btrfs_trans_handle
*trans
,
3414 struct btrfs_root
*root
, struct btrfs_path
*path
,
3415 struct btrfs_disk_key
*key
, u64 bytenr
,
3416 int slot
, int level
)
3418 struct extent_buffer
*lower
;
3422 BUG_ON(!path
->nodes
[level
]);
3423 btrfs_assert_tree_locked(path
->nodes
[level
]);
3424 lower
= path
->nodes
[level
];
3425 nritems
= btrfs_header_nritems(lower
);
3426 BUG_ON(slot
> nritems
);
3427 BUG_ON(nritems
== BTRFS_NODEPTRS_PER_BLOCK(root
));
3428 if (slot
!= nritems
) {
3430 tree_mod_log_eb_move(root
->fs_info
, lower
, slot
+ 1,
3431 slot
, nritems
- slot
);
3432 memmove_extent_buffer(lower
,
3433 btrfs_node_key_ptr_offset(slot
+ 1),
3434 btrfs_node_key_ptr_offset(slot
),
3435 (nritems
- slot
) * sizeof(struct btrfs_key_ptr
));
3438 ret
= tree_mod_log_insert_key(root
->fs_info
, lower
, slot
,
3439 MOD_LOG_KEY_ADD
, GFP_NOFS
);
3442 btrfs_set_node_key(lower
, key
, slot
);
3443 btrfs_set_node_blockptr(lower
, slot
, bytenr
);
3444 WARN_ON(trans
->transid
== 0);
3445 btrfs_set_node_ptr_generation(lower
, slot
, trans
->transid
);
3446 btrfs_set_header_nritems(lower
, nritems
+ 1);
3447 btrfs_mark_buffer_dirty(lower
);
3451 * split the node at the specified level in path in two.
3452 * The path is corrected to point to the appropriate node after the split
3454 * Before splitting this tries to make some room in the node by pushing
3455 * left and right, if either one works, it returns right away.
3457 * returns 0 on success and < 0 on failure
3459 static noinline
int split_node(struct btrfs_trans_handle
*trans
,
3460 struct btrfs_root
*root
,
3461 struct btrfs_path
*path
, int level
)
3463 struct extent_buffer
*c
;
3464 struct extent_buffer
*split
;
3465 struct btrfs_disk_key disk_key
;
3470 c
= path
->nodes
[level
];
3471 WARN_ON(btrfs_header_generation(c
) != trans
->transid
);
3472 if (c
== root
->node
) {
3474 * trying to split the root, lets make a new one
3476 * tree mod log: We don't log_removal old root in
3477 * insert_new_root, because that root buffer will be kept as a
3478 * normal node. We are going to log removal of half of the
3479 * elements below with tree_mod_log_eb_copy. We're holding a
3480 * tree lock on the buffer, which is why we cannot race with
3481 * other tree_mod_log users.
3483 ret
= insert_new_root(trans
, root
, path
, level
+ 1);
3487 ret
= push_nodes_for_insert(trans
, root
, path
, level
);
3488 c
= path
->nodes
[level
];
3489 if (!ret
&& btrfs_header_nritems(c
) <
3490 BTRFS_NODEPTRS_PER_BLOCK(root
) - 3)
3496 c_nritems
= btrfs_header_nritems(c
);
3497 mid
= (c_nritems
+ 1) / 2;
3498 btrfs_node_key(c
, &disk_key
, mid
);
3500 split
= btrfs_alloc_free_block(trans
, root
, root
->nodesize
, 0,
3501 root
->root_key
.objectid
,
3502 &disk_key
, level
, c
->start
, 0);
3504 return PTR_ERR(split
);
3506 root_add_used(root
, root
->nodesize
);
3508 memset_extent_buffer(split
, 0, 0, sizeof(struct btrfs_header
));
3509 btrfs_set_header_level(split
, btrfs_header_level(c
));
3510 btrfs_set_header_bytenr(split
, split
->start
);
3511 btrfs_set_header_generation(split
, trans
->transid
);
3512 btrfs_set_header_backref_rev(split
, BTRFS_MIXED_BACKREF_REV
);
3513 btrfs_set_header_owner(split
, root
->root_key
.objectid
);
3514 write_extent_buffer(split
, root
->fs_info
->fsid
,
3515 btrfs_header_fsid(), BTRFS_FSID_SIZE
);
3516 write_extent_buffer(split
, root
->fs_info
->chunk_tree_uuid
,
3517 btrfs_header_chunk_tree_uuid(split
),
3520 ret
= tree_mod_log_eb_copy(root
->fs_info
, split
, c
, 0,
3521 mid
, c_nritems
- mid
);
3523 btrfs_abort_transaction(trans
, root
, ret
);
3526 copy_extent_buffer(split
, c
,
3527 btrfs_node_key_ptr_offset(0),
3528 btrfs_node_key_ptr_offset(mid
),
3529 (c_nritems
- mid
) * sizeof(struct btrfs_key_ptr
));
3530 btrfs_set_header_nritems(split
, c_nritems
- mid
);
3531 btrfs_set_header_nritems(c
, mid
);
3534 btrfs_mark_buffer_dirty(c
);
3535 btrfs_mark_buffer_dirty(split
);
3537 insert_ptr(trans
, root
, path
, &disk_key
, split
->start
,
3538 path
->slots
[level
+ 1] + 1, level
+ 1);
3540 if (path
->slots
[level
] >= mid
) {
3541 path
->slots
[level
] -= mid
;
3542 btrfs_tree_unlock(c
);
3543 free_extent_buffer(c
);
3544 path
->nodes
[level
] = split
;
3545 path
->slots
[level
+ 1] += 1;
3547 btrfs_tree_unlock(split
);
3548 free_extent_buffer(split
);
3554 * how many bytes are required to store the items in a leaf. start
3555 * and nr indicate which items in the leaf to check. This totals up the
3556 * space used both by the item structs and the item data
3558 static int leaf_space_used(struct extent_buffer
*l
, int start
, int nr
)
3560 struct btrfs_item
*start_item
;
3561 struct btrfs_item
*end_item
;
3562 struct btrfs_map_token token
;
3564 int nritems
= btrfs_header_nritems(l
);
3565 int end
= min(nritems
, start
+ nr
) - 1;
3569 btrfs_init_map_token(&token
);
3570 start_item
= btrfs_item_nr(start
);
3571 end_item
= btrfs_item_nr(end
);
3572 data_len
= btrfs_token_item_offset(l
, start_item
, &token
) +
3573 btrfs_token_item_size(l
, start_item
, &token
);
3574 data_len
= data_len
- btrfs_token_item_offset(l
, end_item
, &token
);
3575 data_len
+= sizeof(struct btrfs_item
) * nr
;
3576 WARN_ON(data_len
< 0);
3581 * The space between the end of the leaf items and
3582 * the start of the leaf data. IOW, how much room
3583 * the leaf has left for both items and data
3585 noinline
int btrfs_leaf_free_space(struct btrfs_root
*root
,
3586 struct extent_buffer
*leaf
)
3588 int nritems
= btrfs_header_nritems(leaf
);
3590 ret
= BTRFS_LEAF_DATA_SIZE(root
) - leaf_space_used(leaf
, 0, nritems
);
3592 btrfs_crit(root
->fs_info
,
3593 "leaf free space ret %d, leaf data size %lu, used %d nritems %d",
3594 ret
, (unsigned long) BTRFS_LEAF_DATA_SIZE(root
),
3595 leaf_space_used(leaf
, 0, nritems
), nritems
);
3601 * min slot controls the lowest index we're willing to push to the
3602 * right. We'll push up to and including min_slot, but no lower
3604 static noinline
int __push_leaf_right(struct btrfs_trans_handle
*trans
,
3605 struct btrfs_root
*root
,
3606 struct btrfs_path
*path
,
3607 int data_size
, int empty
,
3608 struct extent_buffer
*right
,
3609 int free_space
, u32 left_nritems
,
3612 struct extent_buffer
*left
= path
->nodes
[0];
3613 struct extent_buffer
*upper
= path
->nodes
[1];
3614 struct btrfs_map_token token
;
3615 struct btrfs_disk_key disk_key
;
3620 struct btrfs_item
*item
;
3626 btrfs_init_map_token(&token
);
3631 nr
= max_t(u32
, 1, min_slot
);
3633 if (path
->slots
[0] >= left_nritems
)
3634 push_space
+= data_size
;
3636 slot
= path
->slots
[1];
3637 i
= left_nritems
- 1;
3639 item
= btrfs_item_nr(i
);
3641 if (!empty
&& push_items
> 0) {
3642 if (path
->slots
[0] > i
)
3644 if (path
->slots
[0] == i
) {
3645 int space
= btrfs_leaf_free_space(root
, left
);
3646 if (space
+ push_space
* 2 > free_space
)
3651 if (path
->slots
[0] == i
)
3652 push_space
+= data_size
;
3654 this_item_size
= btrfs_item_size(left
, item
);
3655 if (this_item_size
+ sizeof(*item
) + push_space
> free_space
)
3659 push_space
+= this_item_size
+ sizeof(*item
);
3665 if (push_items
== 0)
3668 WARN_ON(!empty
&& push_items
== left_nritems
);
3670 /* push left to right */
3671 right_nritems
= btrfs_header_nritems(right
);
3673 push_space
= btrfs_item_end_nr(left
, left_nritems
- push_items
);
3674 push_space
-= leaf_data_end(root
, left
);
3676 /* make room in the right data area */
3677 data_end
= leaf_data_end(root
, right
);
3678 memmove_extent_buffer(right
,
3679 btrfs_leaf_data(right
) + data_end
- push_space
,
3680 btrfs_leaf_data(right
) + data_end
,
3681 BTRFS_LEAF_DATA_SIZE(root
) - data_end
);
3683 /* copy from the left data area */
3684 copy_extent_buffer(right
, left
, btrfs_leaf_data(right
) +
3685 BTRFS_LEAF_DATA_SIZE(root
) - push_space
,
3686 btrfs_leaf_data(left
) + leaf_data_end(root
, left
),
3689 memmove_extent_buffer(right
, btrfs_item_nr_offset(push_items
),
3690 btrfs_item_nr_offset(0),
3691 right_nritems
* sizeof(struct btrfs_item
));
3693 /* copy the items from left to right */
3694 copy_extent_buffer(right
, left
, btrfs_item_nr_offset(0),
3695 btrfs_item_nr_offset(left_nritems
- push_items
),
3696 push_items
* sizeof(struct btrfs_item
));
3698 /* update the item pointers */
3699 right_nritems
+= push_items
;
3700 btrfs_set_header_nritems(right
, right_nritems
);
3701 push_space
= BTRFS_LEAF_DATA_SIZE(root
);
3702 for (i
= 0; i
< right_nritems
; i
++) {
3703 item
= btrfs_item_nr(i
);
3704 push_space
-= btrfs_token_item_size(right
, item
, &token
);
3705 btrfs_set_token_item_offset(right
, item
, push_space
, &token
);
3708 left_nritems
-= push_items
;
3709 btrfs_set_header_nritems(left
, left_nritems
);
3712 btrfs_mark_buffer_dirty(left
);
3714 clean_tree_block(trans
, root
, left
);
3716 btrfs_mark_buffer_dirty(right
);
3718 btrfs_item_key(right
, &disk_key
, 0);
3719 btrfs_set_node_key(upper
, &disk_key
, slot
+ 1);
3720 btrfs_mark_buffer_dirty(upper
);
3722 /* then fixup the leaf pointer in the path */
3723 if (path
->slots
[0] >= left_nritems
) {
3724 path
->slots
[0] -= left_nritems
;
3725 if (btrfs_header_nritems(path
->nodes
[0]) == 0)
3726 clean_tree_block(trans
, root
, path
->nodes
[0]);
3727 btrfs_tree_unlock(path
->nodes
[0]);
3728 free_extent_buffer(path
->nodes
[0]);
3729 path
->nodes
[0] = right
;
3730 path
->slots
[1] += 1;
3732 btrfs_tree_unlock(right
);
3733 free_extent_buffer(right
);
3738 btrfs_tree_unlock(right
);
3739 free_extent_buffer(right
);
3744 * push some data in the path leaf to the right, trying to free up at
3745 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3747 * returns 1 if the push failed because the other node didn't have enough
3748 * room, 0 if everything worked out and < 0 if there were major errors.
3750 * this will push starting from min_slot to the end of the leaf. It won't
3751 * push any slot lower than min_slot
3753 static int push_leaf_right(struct btrfs_trans_handle
*trans
, struct btrfs_root
3754 *root
, struct btrfs_path
*path
,
3755 int min_data_size
, int data_size
,
3756 int empty
, u32 min_slot
)
3758 struct extent_buffer
*left
= path
->nodes
[0];
3759 struct extent_buffer
*right
;
3760 struct extent_buffer
*upper
;
3766 if (!path
->nodes
[1])
3769 slot
= path
->slots
[1];
3770 upper
= path
->nodes
[1];
3771 if (slot
>= btrfs_header_nritems(upper
) - 1)
3774 btrfs_assert_tree_locked(path
->nodes
[1]);
3776 right
= read_node_slot(root
, upper
, slot
+ 1);
3780 btrfs_tree_lock(right
);
3781 btrfs_set_lock_blocking(right
);
3783 free_space
= btrfs_leaf_free_space(root
, right
);
3784 if (free_space
< data_size
)
3787 /* cow and double check */
3788 ret
= btrfs_cow_block(trans
, root
, right
, upper
,
3793 free_space
= btrfs_leaf_free_space(root
, right
);
3794 if (free_space
< data_size
)
3797 left_nritems
= btrfs_header_nritems(left
);
3798 if (left_nritems
== 0)
3801 if (path
->slots
[0] == left_nritems
&& !empty
) {
3802 /* Key greater than all keys in the leaf, right neighbor has
3803 * enough room for it and we're not emptying our leaf to delete
3804 * it, therefore use right neighbor to insert the new item and
3805 * no need to touch/dirty our left leaft. */
3806 btrfs_tree_unlock(left
);
3807 free_extent_buffer(left
);
3808 path
->nodes
[0] = right
;
3814 return __push_leaf_right(trans
, root
, path
, min_data_size
, empty
,
3815 right
, free_space
, left_nritems
, min_slot
);
3817 btrfs_tree_unlock(right
);
3818 free_extent_buffer(right
);
3823 * push some data in the path leaf to the left, trying to free up at
3824 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3826 * max_slot can put a limit on how far into the leaf we'll push items. The
3827 * item at 'max_slot' won't be touched. Use (u32)-1 to make us do all the
3830 static noinline
int __push_leaf_left(struct btrfs_trans_handle
*trans
,
3831 struct btrfs_root
*root
,
3832 struct btrfs_path
*path
, int data_size
,
3833 int empty
, struct extent_buffer
*left
,
3834 int free_space
, u32 right_nritems
,
3837 struct btrfs_disk_key disk_key
;
3838 struct extent_buffer
*right
= path
->nodes
[0];
3842 struct btrfs_item
*item
;
3843 u32 old_left_nritems
;
3847 u32 old_left_item_size
;
3848 struct btrfs_map_token token
;
3850 btrfs_init_map_token(&token
);
3853 nr
= min(right_nritems
, max_slot
);
3855 nr
= min(right_nritems
- 1, max_slot
);
3857 for (i
= 0; i
< nr
; i
++) {
3858 item
= btrfs_item_nr(i
);
3860 if (!empty
&& push_items
> 0) {
3861 if (path
->slots
[0] < i
)
3863 if (path
->slots
[0] == i
) {
3864 int space
= btrfs_leaf_free_space(root
, right
);
3865 if (space
+ push_space
* 2 > free_space
)
3870 if (path
->slots
[0] == i
)
3871 push_space
+= data_size
;
3873 this_item_size
= btrfs_item_size(right
, item
);
3874 if (this_item_size
+ sizeof(*item
) + push_space
> free_space
)
3878 push_space
+= this_item_size
+ sizeof(*item
);
3881 if (push_items
== 0) {
3885 WARN_ON(!empty
&& push_items
== btrfs_header_nritems(right
));
3887 /* push data from right to left */
3888 copy_extent_buffer(left
, right
,
3889 btrfs_item_nr_offset(btrfs_header_nritems(left
)),
3890 btrfs_item_nr_offset(0),
3891 push_items
* sizeof(struct btrfs_item
));
3893 push_space
= BTRFS_LEAF_DATA_SIZE(root
) -
3894 btrfs_item_offset_nr(right
, push_items
- 1);
3896 copy_extent_buffer(left
, right
, btrfs_leaf_data(left
) +
3897 leaf_data_end(root
, left
) - push_space
,
3898 btrfs_leaf_data(right
) +
3899 btrfs_item_offset_nr(right
, push_items
- 1),
3901 old_left_nritems
= btrfs_header_nritems(left
);
3902 BUG_ON(old_left_nritems
<= 0);
3904 old_left_item_size
= btrfs_item_offset_nr(left
, old_left_nritems
- 1);
3905 for (i
= old_left_nritems
; i
< old_left_nritems
+ push_items
; i
++) {
3908 item
= btrfs_item_nr(i
);
3910 ioff
= btrfs_token_item_offset(left
, item
, &token
);
3911 btrfs_set_token_item_offset(left
, item
,
3912 ioff
- (BTRFS_LEAF_DATA_SIZE(root
) - old_left_item_size
),
3915 btrfs_set_header_nritems(left
, old_left_nritems
+ push_items
);
3917 /* fixup right node */
3918 if (push_items
> right_nritems
)
3919 WARN(1, KERN_CRIT
"push items %d nr %u\n", push_items
,
3922 if (push_items
< right_nritems
) {
3923 push_space
= btrfs_item_offset_nr(right
, push_items
- 1) -
3924 leaf_data_end(root
, right
);
3925 memmove_extent_buffer(right
, btrfs_leaf_data(right
) +
3926 BTRFS_LEAF_DATA_SIZE(root
) - push_space
,
3927 btrfs_leaf_data(right
) +
3928 leaf_data_end(root
, right
), push_space
);
3930 memmove_extent_buffer(right
, btrfs_item_nr_offset(0),
3931 btrfs_item_nr_offset(push_items
),
3932 (btrfs_header_nritems(right
) - push_items
) *
3933 sizeof(struct btrfs_item
));
3935 right_nritems
-= push_items
;
3936 btrfs_set_header_nritems(right
, right_nritems
);
3937 push_space
= BTRFS_LEAF_DATA_SIZE(root
);
3938 for (i
= 0; i
< right_nritems
; i
++) {
3939 item
= btrfs_item_nr(i
);
3941 push_space
= push_space
- btrfs_token_item_size(right
,
3943 btrfs_set_token_item_offset(right
, item
, push_space
, &token
);
3946 btrfs_mark_buffer_dirty(left
);
3948 btrfs_mark_buffer_dirty(right
);
3950 clean_tree_block(trans
, root
, right
);
3952 btrfs_item_key(right
, &disk_key
, 0);
3953 fixup_low_keys(root
, path
, &disk_key
, 1);
3955 /* then fixup the leaf pointer in the path */
3956 if (path
->slots
[0] < push_items
) {
3957 path
->slots
[0] += old_left_nritems
;
3958 btrfs_tree_unlock(path
->nodes
[0]);
3959 free_extent_buffer(path
->nodes
[0]);
3960 path
->nodes
[0] = left
;
3961 path
->slots
[1] -= 1;
3963 btrfs_tree_unlock(left
);
3964 free_extent_buffer(left
);
3965 path
->slots
[0] -= push_items
;
3967 BUG_ON(path
->slots
[0] < 0);
3970 btrfs_tree_unlock(left
);
3971 free_extent_buffer(left
);
3976 * push some data in the path leaf to the left, trying to free up at
3977 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3979 * max_slot can put a limit on how far into the leaf we'll push items. The
3980 * item at 'max_slot' won't be touched. Use (u32)-1 to make us push all the
3983 static int push_leaf_left(struct btrfs_trans_handle
*trans
, struct btrfs_root
3984 *root
, struct btrfs_path
*path
, int min_data_size
,
3985 int data_size
, int empty
, u32 max_slot
)
3987 struct extent_buffer
*right
= path
->nodes
[0];
3988 struct extent_buffer
*left
;
3994 slot
= path
->slots
[1];
3997 if (!path
->nodes
[1])
4000 right_nritems
= btrfs_header_nritems(right
);
4001 if (right_nritems
== 0)
4004 btrfs_assert_tree_locked(path
->nodes
[1]);
4006 left
= read_node_slot(root
, path
->nodes
[1], slot
- 1);
4010 btrfs_tree_lock(left
);
4011 btrfs_set_lock_blocking(left
);
4013 free_space
= btrfs_leaf_free_space(root
, left
);
4014 if (free_space
< data_size
) {
4019 /* cow and double check */
4020 ret
= btrfs_cow_block(trans
, root
, left
,
4021 path
->nodes
[1], slot
- 1, &left
);
4023 /* we hit -ENOSPC, but it isn't fatal here */
4029 free_space
= btrfs_leaf_free_space(root
, left
);
4030 if (free_space
< data_size
) {
4035 return __push_leaf_left(trans
, root
, path
, min_data_size
,
4036 empty
, left
, free_space
, right_nritems
,
4039 btrfs_tree_unlock(left
);
4040 free_extent_buffer(left
);
4045 * split the path's leaf in two, making sure there is at least data_size
4046 * available for the resulting leaf level of the path.
4048 static noinline
void copy_for_split(struct btrfs_trans_handle
*trans
,
4049 struct btrfs_root
*root
,
4050 struct btrfs_path
*path
,
4051 struct extent_buffer
*l
,
4052 struct extent_buffer
*right
,
4053 int slot
, int mid
, int nritems
)
4058 struct btrfs_disk_key disk_key
;
4059 struct btrfs_map_token token
;
4061 btrfs_init_map_token(&token
);
4063 nritems
= nritems
- mid
;
4064 btrfs_set_header_nritems(right
, nritems
);
4065 data_copy_size
= btrfs_item_end_nr(l
, mid
) - leaf_data_end(root
, l
);
4067 copy_extent_buffer(right
, l
, btrfs_item_nr_offset(0),
4068 btrfs_item_nr_offset(mid
),
4069 nritems
* sizeof(struct btrfs_item
));
4071 copy_extent_buffer(right
, l
,
4072 btrfs_leaf_data(right
) + BTRFS_LEAF_DATA_SIZE(root
) -
4073 data_copy_size
, btrfs_leaf_data(l
) +
4074 leaf_data_end(root
, l
), data_copy_size
);
4076 rt_data_off
= BTRFS_LEAF_DATA_SIZE(root
) -
4077 btrfs_item_end_nr(l
, mid
);
4079 for (i
= 0; i
< nritems
; i
++) {
4080 struct btrfs_item
*item
= btrfs_item_nr(i
);
4083 ioff
= btrfs_token_item_offset(right
, item
, &token
);
4084 btrfs_set_token_item_offset(right
, item
,
4085 ioff
+ rt_data_off
, &token
);
4088 btrfs_set_header_nritems(l
, mid
);
4089 btrfs_item_key(right
, &disk_key
, 0);
4090 insert_ptr(trans
, root
, path
, &disk_key
, right
->start
,
4091 path
->slots
[1] + 1, 1);
4093 btrfs_mark_buffer_dirty(right
);
4094 btrfs_mark_buffer_dirty(l
);
4095 BUG_ON(path
->slots
[0] != slot
);
4098 btrfs_tree_unlock(path
->nodes
[0]);
4099 free_extent_buffer(path
->nodes
[0]);
4100 path
->nodes
[0] = right
;
4101 path
->slots
[0] -= mid
;
4102 path
->slots
[1] += 1;
4104 btrfs_tree_unlock(right
);
4105 free_extent_buffer(right
);
4108 BUG_ON(path
->slots
[0] < 0);
4112 * double splits happen when we need to insert a big item in the middle
4113 * of a leaf. A double split can leave us with 3 mostly empty leaves:
4114 * leaf: [ slots 0 - N] [ our target ] [ N + 1 - total in leaf ]
4117 * We avoid this by trying to push the items on either side of our target
4118 * into the adjacent leaves. If all goes well we can avoid the double split
4121 static noinline
int push_for_double_split(struct btrfs_trans_handle
*trans
,
4122 struct btrfs_root
*root
,
4123 struct btrfs_path
*path
,
4130 int space_needed
= data_size
;
4132 slot
= path
->slots
[0];
4133 if (slot
< btrfs_header_nritems(path
->nodes
[0]))
4134 space_needed
-= btrfs_leaf_free_space(root
, path
->nodes
[0]);
4137 * try to push all the items after our slot into the
4140 ret
= push_leaf_right(trans
, root
, path
, 1, space_needed
, 0, slot
);
4147 nritems
= btrfs_header_nritems(path
->nodes
[0]);
4149 * our goal is to get our slot at the start or end of a leaf. If
4150 * we've done so we're done
4152 if (path
->slots
[0] == 0 || path
->slots
[0] == nritems
)
4155 if (btrfs_leaf_free_space(root
, path
->nodes
[0]) >= data_size
)
4158 /* try to push all the items before our slot into the next leaf */
4159 slot
= path
->slots
[0];
4160 ret
= push_leaf_left(trans
, root
, path
, 1, space_needed
, 0, slot
);
4173 * split the path's leaf in two, making sure there is at least data_size
4174 * available for the resulting leaf level of the path.
4176 * returns 0 if all went well and < 0 on failure.
4178 static noinline
int split_leaf(struct btrfs_trans_handle
*trans
,
4179 struct btrfs_root
*root
,
4180 struct btrfs_key
*ins_key
,
4181 struct btrfs_path
*path
, int data_size
,
4184 struct btrfs_disk_key disk_key
;
4185 struct extent_buffer
*l
;
4189 struct extent_buffer
*right
;
4193 int num_doubles
= 0;
4194 int tried_avoid_double
= 0;
4197 slot
= path
->slots
[0];
4198 if (extend
&& data_size
+ btrfs_item_size_nr(l
, slot
) +
4199 sizeof(struct btrfs_item
) > BTRFS_LEAF_DATA_SIZE(root
))
4202 /* first try to make some room by pushing left and right */
4203 if (data_size
&& path
->nodes
[1]) {
4204 int space_needed
= data_size
;
4206 if (slot
< btrfs_header_nritems(l
))
4207 space_needed
-= btrfs_leaf_free_space(root
, l
);
4209 wret
= push_leaf_right(trans
, root
, path
, space_needed
,
4210 space_needed
, 0, 0);
4214 wret
= push_leaf_left(trans
, root
, path
, space_needed
,
4215 space_needed
, 0, (u32
)-1);
4221 /* did the pushes work? */
4222 if (btrfs_leaf_free_space(root
, l
) >= data_size
)
4226 if (!path
->nodes
[1]) {
4227 ret
= insert_new_root(trans
, root
, path
, 1);
4234 slot
= path
->slots
[0];
4235 nritems
= btrfs_header_nritems(l
);
4236 mid
= (nritems
+ 1) / 2;
4240 leaf_space_used(l
, mid
, nritems
- mid
) + data_size
>
4241 BTRFS_LEAF_DATA_SIZE(root
)) {
4242 if (slot
>= nritems
) {
4246 if (mid
!= nritems
&&
4247 leaf_space_used(l
, mid
, nritems
- mid
) +
4248 data_size
> BTRFS_LEAF_DATA_SIZE(root
)) {
4249 if (data_size
&& !tried_avoid_double
)
4250 goto push_for_double
;
4256 if (leaf_space_used(l
, 0, mid
) + data_size
>
4257 BTRFS_LEAF_DATA_SIZE(root
)) {
4258 if (!extend
&& data_size
&& slot
== 0) {
4260 } else if ((extend
|| !data_size
) && slot
== 0) {
4264 if (mid
!= nritems
&&
4265 leaf_space_used(l
, mid
, nritems
- mid
) +
4266 data_size
> BTRFS_LEAF_DATA_SIZE(root
)) {
4267 if (data_size
&& !tried_avoid_double
)
4268 goto push_for_double
;
4276 btrfs_cpu_key_to_disk(&disk_key
, ins_key
);
4278 btrfs_item_key(l
, &disk_key
, mid
);
4280 right
= btrfs_alloc_free_block(trans
, root
, root
->nodesize
, 0,
4281 root
->root_key
.objectid
,
4282 &disk_key
, 0, l
->start
, 0);
4284 return PTR_ERR(right
);
4286 root_add_used(root
, root
->nodesize
);
4288 memset_extent_buffer(right
, 0, 0, sizeof(struct btrfs_header
));
4289 btrfs_set_header_bytenr(right
, right
->start
);
4290 btrfs_set_header_generation(right
, trans
->transid
);
4291 btrfs_set_header_backref_rev(right
, BTRFS_MIXED_BACKREF_REV
);
4292 btrfs_set_header_owner(right
, root
->root_key
.objectid
);
4293 btrfs_set_header_level(right
, 0);
4294 write_extent_buffer(right
, root
->fs_info
->fsid
,
4295 btrfs_header_fsid(), BTRFS_FSID_SIZE
);
4297 write_extent_buffer(right
, root
->fs_info
->chunk_tree_uuid
,
4298 btrfs_header_chunk_tree_uuid(right
),
4303 btrfs_set_header_nritems(right
, 0);
4304 insert_ptr(trans
, root
, path
, &disk_key
, right
->start
,
4305 path
->slots
[1] + 1, 1);
4306 btrfs_tree_unlock(path
->nodes
[0]);
4307 free_extent_buffer(path
->nodes
[0]);
4308 path
->nodes
[0] = right
;
4310 path
->slots
[1] += 1;
4312 btrfs_set_header_nritems(right
, 0);
4313 insert_ptr(trans
, root
, path
, &disk_key
, right
->start
,
4315 btrfs_tree_unlock(path
->nodes
[0]);
4316 free_extent_buffer(path
->nodes
[0]);
4317 path
->nodes
[0] = right
;
4319 if (path
->slots
[1] == 0)
4320 fixup_low_keys(root
, path
, &disk_key
, 1);
4322 btrfs_mark_buffer_dirty(right
);
4326 copy_for_split(trans
, root
, path
, l
, right
, slot
, mid
, nritems
);
4329 BUG_ON(num_doubles
!= 0);
4337 push_for_double_split(trans
, root
, path
, data_size
);
4338 tried_avoid_double
= 1;
4339 if (btrfs_leaf_free_space(root
, path
->nodes
[0]) >= data_size
)
4344 static noinline
int setup_leaf_for_split(struct btrfs_trans_handle
*trans
,
4345 struct btrfs_root
*root
,
4346 struct btrfs_path
*path
, int ins_len
)
4348 struct btrfs_key key
;
4349 struct extent_buffer
*leaf
;
4350 struct btrfs_file_extent_item
*fi
;
4355 leaf
= path
->nodes
[0];
4356 btrfs_item_key_to_cpu(leaf
, &key
, path
->slots
[0]);
4358 BUG_ON(key
.type
!= BTRFS_EXTENT_DATA_KEY
&&
4359 key
.type
!= BTRFS_EXTENT_CSUM_KEY
);
4361 if (btrfs_leaf_free_space(root
, leaf
) >= ins_len
)
4364 item_size
= btrfs_item_size_nr(leaf
, path
->slots
[0]);
4365 if (key
.type
== BTRFS_EXTENT_DATA_KEY
) {
4366 fi
= btrfs_item_ptr(leaf
, path
->slots
[0],
4367 struct btrfs_file_extent_item
);
4368 extent_len
= btrfs_file_extent_num_bytes(leaf
, fi
);
4370 btrfs_release_path(path
);
4372 path
->keep_locks
= 1;
4373 path
->search_for_split
= 1;
4374 ret
= btrfs_search_slot(trans
, root
, &key
, path
, 0, 1);
4375 path
->search_for_split
= 0;
4380 leaf
= path
->nodes
[0];
4381 /* if our item isn't there or got smaller, return now */
4382 if (ret
> 0 || item_size
!= btrfs_item_size_nr(leaf
, path
->slots
[0]))
4385 /* the leaf has changed, it now has room. return now */
4386 if (btrfs_leaf_free_space(root
, path
->nodes
[0]) >= ins_len
)
4389 if (key
.type
== BTRFS_EXTENT_DATA_KEY
) {
4390 fi
= btrfs_item_ptr(leaf
, path
->slots
[0],
4391 struct btrfs_file_extent_item
);
4392 if (extent_len
!= btrfs_file_extent_num_bytes(leaf
, fi
))
4396 btrfs_set_path_blocking(path
);
4397 ret
= split_leaf(trans
, root
, &key
, path
, ins_len
, 1);
4401 path
->keep_locks
= 0;
4402 btrfs_unlock_up_safe(path
, 1);
4405 path
->keep_locks
= 0;
4409 static noinline
int split_item(struct btrfs_trans_handle
*trans
,
4410 struct btrfs_root
*root
,
4411 struct btrfs_path
*path
,
4412 struct btrfs_key
*new_key
,
4413 unsigned long split_offset
)
4415 struct extent_buffer
*leaf
;
4416 struct btrfs_item
*item
;
4417 struct btrfs_item
*new_item
;
4423 struct btrfs_disk_key disk_key
;
4425 leaf
= path
->nodes
[0];
4426 BUG_ON(btrfs_leaf_free_space(root
, leaf
) < sizeof(struct btrfs_item
));
4428 btrfs_set_path_blocking(path
);
4430 item
= btrfs_item_nr(path
->slots
[0]);
4431 orig_offset
= btrfs_item_offset(leaf
, item
);
4432 item_size
= btrfs_item_size(leaf
, item
);
4434 buf
= kmalloc(item_size
, GFP_NOFS
);
4438 read_extent_buffer(leaf
, buf
, btrfs_item_ptr_offset(leaf
,
4439 path
->slots
[0]), item_size
);
4441 slot
= path
->slots
[0] + 1;
4442 nritems
= btrfs_header_nritems(leaf
);
4443 if (slot
!= nritems
) {
4444 /* shift the items */
4445 memmove_extent_buffer(leaf
, btrfs_item_nr_offset(slot
+ 1),
4446 btrfs_item_nr_offset(slot
),
4447 (nritems
- slot
) * sizeof(struct btrfs_item
));
4450 btrfs_cpu_key_to_disk(&disk_key
, new_key
);
4451 btrfs_set_item_key(leaf
, &disk_key
, slot
);
4453 new_item
= btrfs_item_nr(slot
);
4455 btrfs_set_item_offset(leaf
, new_item
, orig_offset
);
4456 btrfs_set_item_size(leaf
, new_item
, item_size
- split_offset
);
4458 btrfs_set_item_offset(leaf
, item
,
4459 orig_offset
+ item_size
- split_offset
);
4460 btrfs_set_item_size(leaf
, item
, split_offset
);
4462 btrfs_set_header_nritems(leaf
, nritems
+ 1);
4464 /* write the data for the start of the original item */
4465 write_extent_buffer(leaf
, buf
,
4466 btrfs_item_ptr_offset(leaf
, path
->slots
[0]),
4469 /* write the data for the new item */
4470 write_extent_buffer(leaf
, buf
+ split_offset
,
4471 btrfs_item_ptr_offset(leaf
, slot
),
4472 item_size
- split_offset
);
4473 btrfs_mark_buffer_dirty(leaf
);
4475 BUG_ON(btrfs_leaf_free_space(root
, leaf
) < 0);
4481 * This function splits a single item into two items,
4482 * giving 'new_key' to the new item and splitting the
4483 * old one at split_offset (from the start of the item).
4485 * The path may be released by this operation. After
4486 * the split, the path is pointing to the old item. The
4487 * new item is going to be in the same node as the old one.
4489 * Note, the item being split must be smaller enough to live alone on
4490 * a tree block with room for one extra struct btrfs_item
4492 * This allows us to split the item in place, keeping a lock on the
4493 * leaf the entire time.
4495 int btrfs_split_item(struct btrfs_trans_handle
*trans
,
4496 struct btrfs_root
*root
,
4497 struct btrfs_path
*path
,
4498 struct btrfs_key
*new_key
,
4499 unsigned long split_offset
)
4502 ret
= setup_leaf_for_split(trans
, root
, path
,
4503 sizeof(struct btrfs_item
));
4507 ret
= split_item(trans
, root
, path
, new_key
, split_offset
);
4512 * This function duplicate a item, giving 'new_key' to the new item.
4513 * It guarantees both items live in the same tree leaf and the new item
4514 * is contiguous with the original item.
4516 * This allows us to split file extent in place, keeping a lock on the
4517 * leaf the entire time.
4519 int btrfs_duplicate_item(struct btrfs_trans_handle
*trans
,
4520 struct btrfs_root
*root
,
4521 struct btrfs_path
*path
,
4522 struct btrfs_key
*new_key
)
4524 struct extent_buffer
*leaf
;
4528 leaf
= path
->nodes
[0];
4529 item_size
= btrfs_item_size_nr(leaf
, path
->slots
[0]);
4530 ret
= setup_leaf_for_split(trans
, root
, path
,
4531 item_size
+ sizeof(struct btrfs_item
));
4536 setup_items_for_insert(root
, path
, new_key
, &item_size
,
4537 item_size
, item_size
+
4538 sizeof(struct btrfs_item
), 1);
4539 leaf
= path
->nodes
[0];
4540 memcpy_extent_buffer(leaf
,
4541 btrfs_item_ptr_offset(leaf
, path
->slots
[0]),
4542 btrfs_item_ptr_offset(leaf
, path
->slots
[0] - 1),
4548 * make the item pointed to by the path smaller. new_size indicates
4549 * how small to make it, and from_end tells us if we just chop bytes
4550 * off the end of the item or if we shift the item to chop bytes off
4553 void btrfs_truncate_item(struct btrfs_root
*root
, struct btrfs_path
*path
,
4554 u32 new_size
, int from_end
)
4557 struct extent_buffer
*leaf
;
4558 struct btrfs_item
*item
;
4560 unsigned int data_end
;
4561 unsigned int old_data_start
;
4562 unsigned int old_size
;
4563 unsigned int size_diff
;
4565 struct btrfs_map_token token
;
4567 btrfs_init_map_token(&token
);
4569 leaf
= path
->nodes
[0];
4570 slot
= path
->slots
[0];
4572 old_size
= btrfs_item_size_nr(leaf
, slot
);
4573 if (old_size
== new_size
)
4576 nritems
= btrfs_header_nritems(leaf
);
4577 data_end
= leaf_data_end(root
, leaf
);
4579 old_data_start
= btrfs_item_offset_nr(leaf
, slot
);
4581 size_diff
= old_size
- new_size
;
4584 BUG_ON(slot
>= nritems
);
4587 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4589 /* first correct the data pointers */
4590 for (i
= slot
; i
< nritems
; i
++) {
4592 item
= btrfs_item_nr(i
);
4594 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4595 btrfs_set_token_item_offset(leaf
, item
,
4596 ioff
+ size_diff
, &token
);
4599 /* shift the data */
4601 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4602 data_end
+ size_diff
, btrfs_leaf_data(leaf
) +
4603 data_end
, old_data_start
+ new_size
- data_end
);
4605 struct btrfs_disk_key disk_key
;
4608 btrfs_item_key(leaf
, &disk_key
, slot
);
4610 if (btrfs_disk_key_type(&disk_key
) == BTRFS_EXTENT_DATA_KEY
) {
4612 struct btrfs_file_extent_item
*fi
;
4614 fi
= btrfs_item_ptr(leaf
, slot
,
4615 struct btrfs_file_extent_item
);
4616 fi
= (struct btrfs_file_extent_item
*)(
4617 (unsigned long)fi
- size_diff
);
4619 if (btrfs_file_extent_type(leaf
, fi
) ==
4620 BTRFS_FILE_EXTENT_INLINE
) {
4621 ptr
= btrfs_item_ptr_offset(leaf
, slot
);
4622 memmove_extent_buffer(leaf
, ptr
,
4624 offsetof(struct btrfs_file_extent_item
,
4629 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4630 data_end
+ size_diff
, btrfs_leaf_data(leaf
) +
4631 data_end
, old_data_start
- data_end
);
4633 offset
= btrfs_disk_key_offset(&disk_key
);
4634 btrfs_set_disk_key_offset(&disk_key
, offset
+ size_diff
);
4635 btrfs_set_item_key(leaf
, &disk_key
, slot
);
4637 fixup_low_keys(root
, path
, &disk_key
, 1);
4640 item
= btrfs_item_nr(slot
);
4641 btrfs_set_item_size(leaf
, item
, new_size
);
4642 btrfs_mark_buffer_dirty(leaf
);
4644 if (btrfs_leaf_free_space(root
, leaf
) < 0) {
4645 btrfs_print_leaf(root
, leaf
);
4651 * make the item pointed to by the path bigger, data_size is the added size.
4653 void btrfs_extend_item(struct btrfs_root
*root
, struct btrfs_path
*path
,
4657 struct extent_buffer
*leaf
;
4658 struct btrfs_item
*item
;
4660 unsigned int data_end
;
4661 unsigned int old_data
;
4662 unsigned int old_size
;
4664 struct btrfs_map_token token
;
4666 btrfs_init_map_token(&token
);
4668 leaf
= path
->nodes
[0];
4670 nritems
= btrfs_header_nritems(leaf
);
4671 data_end
= leaf_data_end(root
, leaf
);
4673 if (btrfs_leaf_free_space(root
, leaf
) < data_size
) {
4674 btrfs_print_leaf(root
, leaf
);
4677 slot
= path
->slots
[0];
4678 old_data
= btrfs_item_end_nr(leaf
, slot
);
4681 if (slot
>= nritems
) {
4682 btrfs_print_leaf(root
, leaf
);
4683 btrfs_crit(root
->fs_info
, "slot %d too large, nritems %d",
4689 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4691 /* first correct the data pointers */
4692 for (i
= slot
; i
< nritems
; i
++) {
4694 item
= btrfs_item_nr(i
);
4696 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4697 btrfs_set_token_item_offset(leaf
, item
,
4698 ioff
- data_size
, &token
);
4701 /* shift the data */
4702 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4703 data_end
- data_size
, btrfs_leaf_data(leaf
) +
4704 data_end
, old_data
- data_end
);
4706 data_end
= old_data
;
4707 old_size
= btrfs_item_size_nr(leaf
, slot
);
4708 item
= btrfs_item_nr(slot
);
4709 btrfs_set_item_size(leaf
, item
, old_size
+ data_size
);
4710 btrfs_mark_buffer_dirty(leaf
);
4712 if (btrfs_leaf_free_space(root
, leaf
) < 0) {
4713 btrfs_print_leaf(root
, leaf
);
4719 * this is a helper for btrfs_insert_empty_items, the main goal here is
4720 * to save stack depth by doing the bulk of the work in a function
4721 * that doesn't call btrfs_search_slot
4723 void setup_items_for_insert(struct btrfs_root
*root
, struct btrfs_path
*path
,
4724 struct btrfs_key
*cpu_key
, u32
*data_size
,
4725 u32 total_data
, u32 total_size
, int nr
)
4727 struct btrfs_item
*item
;
4730 unsigned int data_end
;
4731 struct btrfs_disk_key disk_key
;
4732 struct extent_buffer
*leaf
;
4734 struct btrfs_map_token token
;
4736 if (path
->slots
[0] == 0) {
4737 btrfs_cpu_key_to_disk(&disk_key
, cpu_key
);
4738 fixup_low_keys(root
, path
, &disk_key
, 1);
4740 btrfs_unlock_up_safe(path
, 1);
4742 btrfs_init_map_token(&token
);
4744 leaf
= path
->nodes
[0];
4745 slot
= path
->slots
[0];
4747 nritems
= btrfs_header_nritems(leaf
);
4748 data_end
= leaf_data_end(root
, leaf
);
4750 if (btrfs_leaf_free_space(root
, leaf
) < total_size
) {
4751 btrfs_print_leaf(root
, leaf
);
4752 btrfs_crit(root
->fs_info
, "not enough freespace need %u have %d",
4753 total_size
, btrfs_leaf_free_space(root
, leaf
));
4757 if (slot
!= nritems
) {
4758 unsigned int old_data
= btrfs_item_end_nr(leaf
, slot
);
4760 if (old_data
< data_end
) {
4761 btrfs_print_leaf(root
, leaf
);
4762 btrfs_crit(root
->fs_info
, "slot %d old_data %d data_end %d",
4763 slot
, old_data
, data_end
);
4767 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4769 /* first correct the data pointers */
4770 for (i
= slot
; i
< nritems
; i
++) {
4773 item
= btrfs_item_nr( i
);
4774 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4775 btrfs_set_token_item_offset(leaf
, item
,
4776 ioff
- total_data
, &token
);
4778 /* shift the items */
4779 memmove_extent_buffer(leaf
, btrfs_item_nr_offset(slot
+ nr
),
4780 btrfs_item_nr_offset(slot
),
4781 (nritems
- slot
) * sizeof(struct btrfs_item
));
4783 /* shift the data */
4784 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4785 data_end
- total_data
, btrfs_leaf_data(leaf
) +
4786 data_end
, old_data
- data_end
);
4787 data_end
= old_data
;
4790 /* setup the item for the new data */
4791 for (i
= 0; i
< nr
; i
++) {
4792 btrfs_cpu_key_to_disk(&disk_key
, cpu_key
+ i
);
4793 btrfs_set_item_key(leaf
, &disk_key
, slot
+ i
);
4794 item
= btrfs_item_nr(slot
+ i
);
4795 btrfs_set_token_item_offset(leaf
, item
,
4796 data_end
- data_size
[i
], &token
);
4797 data_end
-= data_size
[i
];
4798 btrfs_set_token_item_size(leaf
, item
, data_size
[i
], &token
);
4801 btrfs_set_header_nritems(leaf
, nritems
+ nr
);
4802 btrfs_mark_buffer_dirty(leaf
);
4804 if (btrfs_leaf_free_space(root
, leaf
) < 0) {
4805 btrfs_print_leaf(root
, leaf
);
4811 * Given a key and some data, insert items into the tree.
4812 * This does all the path init required, making room in the tree if needed.
4814 int btrfs_insert_empty_items(struct btrfs_trans_handle
*trans
,
4815 struct btrfs_root
*root
,
4816 struct btrfs_path
*path
,
4817 struct btrfs_key
*cpu_key
, u32
*data_size
,
4826 for (i
= 0; i
< nr
; i
++)
4827 total_data
+= data_size
[i
];
4829 total_size
= total_data
+ (nr
* sizeof(struct btrfs_item
));
4830 ret
= btrfs_search_slot(trans
, root
, cpu_key
, path
, total_size
, 1);
4836 slot
= path
->slots
[0];
4839 setup_items_for_insert(root
, path
, cpu_key
, data_size
,
4840 total_data
, total_size
, nr
);
4845 * Given a key and some data, insert an item into the tree.
4846 * This does all the path init required, making room in the tree if needed.
4848 int btrfs_insert_item(struct btrfs_trans_handle
*trans
, struct btrfs_root
4849 *root
, struct btrfs_key
*cpu_key
, void *data
, u32
4853 struct btrfs_path
*path
;
4854 struct extent_buffer
*leaf
;
4857 path
= btrfs_alloc_path();
4860 ret
= btrfs_insert_empty_item(trans
, root
, path
, cpu_key
, data_size
);
4862 leaf
= path
->nodes
[0];
4863 ptr
= btrfs_item_ptr_offset(leaf
, path
->slots
[0]);
4864 write_extent_buffer(leaf
, data
, ptr
, data_size
);
4865 btrfs_mark_buffer_dirty(leaf
);
4867 btrfs_free_path(path
);
4872 * delete the pointer from a given node.
4874 * the tree should have been previously balanced so the deletion does not
4877 static void del_ptr(struct btrfs_root
*root
, struct btrfs_path
*path
,
4878 int level
, int slot
)
4880 struct extent_buffer
*parent
= path
->nodes
[level
];
4884 nritems
= btrfs_header_nritems(parent
);
4885 if (slot
!= nritems
- 1) {
4887 tree_mod_log_eb_move(root
->fs_info
, parent
, slot
,
4888 slot
+ 1, nritems
- slot
- 1);
4889 memmove_extent_buffer(parent
,
4890 btrfs_node_key_ptr_offset(slot
),
4891 btrfs_node_key_ptr_offset(slot
+ 1),
4892 sizeof(struct btrfs_key_ptr
) *
4893 (nritems
- slot
- 1));
4895 ret
= tree_mod_log_insert_key(root
->fs_info
, parent
, slot
,
4896 MOD_LOG_KEY_REMOVE
, GFP_NOFS
);
4901 btrfs_set_header_nritems(parent
, nritems
);
4902 if (nritems
== 0 && parent
== root
->node
) {
4903 BUG_ON(btrfs_header_level(root
->node
) != 1);
4904 /* just turn the root into a leaf and break */
4905 btrfs_set_header_level(root
->node
, 0);
4906 } else if (slot
== 0) {
4907 struct btrfs_disk_key disk_key
;
4909 btrfs_node_key(parent
, &disk_key
, 0);
4910 fixup_low_keys(root
, path
, &disk_key
, level
+ 1);
4912 btrfs_mark_buffer_dirty(parent
);
4916 * a helper function to delete the leaf pointed to by path->slots[1] and
4919 * This deletes the pointer in path->nodes[1] and frees the leaf
4920 * block extent. zero is returned if it all worked out, < 0 otherwise.
4922 * The path must have already been setup for deleting the leaf, including
4923 * all the proper balancing. path->nodes[1] must be locked.
4925 static noinline
void btrfs_del_leaf(struct btrfs_trans_handle
*trans
,
4926 struct btrfs_root
*root
,
4927 struct btrfs_path
*path
,
4928 struct extent_buffer
*leaf
)
4930 WARN_ON(btrfs_header_generation(leaf
) != trans
->transid
);
4931 del_ptr(root
, path
, 1, path
->slots
[1]);
4934 * btrfs_free_extent is expensive, we want to make sure we
4935 * aren't holding any locks when we call it
4937 btrfs_unlock_up_safe(path
, 0);
4939 root_sub_used(root
, leaf
->len
);
4941 extent_buffer_get(leaf
);
4942 btrfs_free_tree_block(trans
, root
, leaf
, 0, 1);
4943 free_extent_buffer_stale(leaf
);
4946 * delete the item at the leaf level in path. If that empties
4947 * the leaf, remove it from the tree
4949 int btrfs_del_items(struct btrfs_trans_handle
*trans
, struct btrfs_root
*root
,
4950 struct btrfs_path
*path
, int slot
, int nr
)
4952 struct extent_buffer
*leaf
;
4953 struct btrfs_item
*item
;
4960 struct btrfs_map_token token
;
4962 btrfs_init_map_token(&token
);
4964 leaf
= path
->nodes
[0];
4965 last_off
= btrfs_item_offset_nr(leaf
, slot
+ nr
- 1);
4967 for (i
= 0; i
< nr
; i
++)
4968 dsize
+= btrfs_item_size_nr(leaf
, slot
+ i
);
4970 nritems
= btrfs_header_nritems(leaf
);
4972 if (slot
+ nr
!= nritems
) {
4973 int data_end
= leaf_data_end(root
, leaf
);
4975 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4977 btrfs_leaf_data(leaf
) + data_end
,
4978 last_off
- data_end
);
4980 for (i
= slot
+ nr
; i
< nritems
; i
++) {
4983 item
= btrfs_item_nr(i
);
4984 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4985 btrfs_set_token_item_offset(leaf
, item
,
4986 ioff
+ dsize
, &token
);
4989 memmove_extent_buffer(leaf
, btrfs_item_nr_offset(slot
),
4990 btrfs_item_nr_offset(slot
+ nr
),
4991 sizeof(struct btrfs_item
) *
4992 (nritems
- slot
- nr
));
4994 btrfs_set_header_nritems(leaf
, nritems
- nr
);
4997 /* delete the leaf if we've emptied it */
4999 if (leaf
== root
->node
) {
5000 btrfs_set_header_level(leaf
, 0);
5002 btrfs_set_path_blocking(path
);
5003 clean_tree_block(trans
, root
, leaf
);
5004 btrfs_del_leaf(trans
, root
, path
, leaf
);
5007 int used
= leaf_space_used(leaf
, 0, nritems
);
5009 struct btrfs_disk_key disk_key
;
5011 btrfs_item_key(leaf
, &disk_key
, 0);
5012 fixup_low_keys(root
, path
, &disk_key
, 1);
5015 /* delete the leaf if it is mostly empty */
5016 if (used
< BTRFS_LEAF_DATA_SIZE(root
) / 3) {
5017 /* push_leaf_left fixes the path.
5018 * make sure the path still points to our leaf
5019 * for possible call to del_ptr below
5021 slot
= path
->slots
[1];
5022 extent_buffer_get(leaf
);
5024 btrfs_set_path_blocking(path
);
5025 wret
= push_leaf_left(trans
, root
, path
, 1, 1,
5027 if (wret
< 0 && wret
!= -ENOSPC
)
5030 if (path
->nodes
[0] == leaf
&&
5031 btrfs_header_nritems(leaf
)) {
5032 wret
= push_leaf_right(trans
, root
, path
, 1,
5034 if (wret
< 0 && wret
!= -ENOSPC
)
5038 if (btrfs_header_nritems(leaf
) == 0) {
5039 path
->slots
[1] = slot
;
5040 btrfs_del_leaf(trans
, root
, path
, leaf
);
5041 free_extent_buffer(leaf
);
5044 /* if we're still in the path, make sure
5045 * we're dirty. Otherwise, one of the
5046 * push_leaf functions must have already
5047 * dirtied this buffer
5049 if (path
->nodes
[0] == leaf
)
5050 btrfs_mark_buffer_dirty(leaf
);
5051 free_extent_buffer(leaf
);
5054 btrfs_mark_buffer_dirty(leaf
);
5061 * search the tree again to find a leaf with lesser keys
5062 * returns 0 if it found something or 1 if there are no lesser leaves.
5063 * returns < 0 on io errors.
5065 * This may release the path, and so you may lose any locks held at the
5068 int btrfs_prev_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
)
5070 struct btrfs_key key
;
5071 struct btrfs_disk_key found_key
;
5074 btrfs_item_key_to_cpu(path
->nodes
[0], &key
, 0);
5076 if (key
.offset
> 0) {
5078 } else if (key
.type
> 0) {
5080 key
.offset
= (u64
)-1;
5081 } else if (key
.objectid
> 0) {
5084 key
.offset
= (u64
)-1;
5089 btrfs_release_path(path
);
5090 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
5093 btrfs_item_key(path
->nodes
[0], &found_key
, 0);
5094 ret
= comp_keys(&found_key
, &key
);
5096 * We might have had an item with the previous key in the tree right
5097 * before we released our path. And after we released our path, that
5098 * item might have been pushed to the first slot (0) of the leaf we
5099 * were holding due to a tree balance. Alternatively, an item with the
5100 * previous key can exist as the only element of a leaf (big fat item).
5101 * Therefore account for these 2 cases, so that our callers (like
5102 * btrfs_previous_item) don't miss an existing item with a key matching
5103 * the previous key we computed above.
5111 * A helper function to walk down the tree starting at min_key, and looking
5112 * for nodes or leaves that are have a minimum transaction id.
5113 * This is used by the btree defrag code, and tree logging
5115 * This does not cow, but it does stuff the starting key it finds back
5116 * into min_key, so you can call btrfs_search_slot with cow=1 on the
5117 * key and get a writable path.
5119 * This does lock as it descends, and path->keep_locks should be set
5120 * to 1 by the caller.
5122 * This honors path->lowest_level to prevent descent past a given level
5125 * min_trans indicates the oldest transaction that you are interested
5126 * in walking through. Any nodes or leaves older than min_trans are
5127 * skipped over (without reading them).
5129 * returns zero if something useful was found, < 0 on error and 1 if there
5130 * was nothing in the tree that matched the search criteria.
5132 int btrfs_search_forward(struct btrfs_root
*root
, struct btrfs_key
*min_key
,
5133 struct btrfs_path
*path
,
5136 struct extent_buffer
*cur
;
5137 struct btrfs_key found_key
;
5143 int keep_locks
= path
->keep_locks
;
5145 path
->keep_locks
= 1;
5147 cur
= btrfs_read_lock_root_node(root
);
5148 level
= btrfs_header_level(cur
);
5149 WARN_ON(path
->nodes
[level
]);
5150 path
->nodes
[level
] = cur
;
5151 path
->locks
[level
] = BTRFS_READ_LOCK
;
5153 if (btrfs_header_generation(cur
) < min_trans
) {
5158 nritems
= btrfs_header_nritems(cur
);
5159 level
= btrfs_header_level(cur
);
5160 sret
= bin_search(cur
, min_key
, level
, &slot
);
5162 /* at the lowest level, we're done, setup the path and exit */
5163 if (level
== path
->lowest_level
) {
5164 if (slot
>= nritems
)
5167 path
->slots
[level
] = slot
;
5168 btrfs_item_key_to_cpu(cur
, &found_key
, slot
);
5171 if (sret
&& slot
> 0)
5174 * check this node pointer against the min_trans parameters.
5175 * If it is too old, old, skip to the next one.
5177 while (slot
< nritems
) {
5180 gen
= btrfs_node_ptr_generation(cur
, slot
);
5181 if (gen
< min_trans
) {
5189 * we didn't find a candidate key in this node, walk forward
5190 * and find another one
5192 if (slot
>= nritems
) {
5193 path
->slots
[level
] = slot
;
5194 btrfs_set_path_blocking(path
);
5195 sret
= btrfs_find_next_key(root
, path
, min_key
, level
,
5198 btrfs_release_path(path
);
5204 /* save our key for returning back */
5205 btrfs_node_key_to_cpu(cur
, &found_key
, slot
);
5206 path
->slots
[level
] = slot
;
5207 if (level
== path
->lowest_level
) {
5211 btrfs_set_path_blocking(path
);
5212 cur
= read_node_slot(root
, cur
, slot
);
5213 BUG_ON(!cur
); /* -ENOMEM */
5215 btrfs_tree_read_lock(cur
);
5217 path
->locks
[level
- 1] = BTRFS_READ_LOCK
;
5218 path
->nodes
[level
- 1] = cur
;
5219 unlock_up(path
, level
, 1, 0, NULL
);
5220 btrfs_clear_path_blocking(path
, NULL
, 0);
5223 path
->keep_locks
= keep_locks
;
5225 btrfs_unlock_up_safe(path
, path
->lowest_level
+ 1);
5226 btrfs_set_path_blocking(path
);
5227 memcpy(min_key
, &found_key
, sizeof(found_key
));
5232 static void tree_move_down(struct btrfs_root
*root
,
5233 struct btrfs_path
*path
,
5234 int *level
, int root_level
)
5236 BUG_ON(*level
== 0);
5237 path
->nodes
[*level
- 1] = read_node_slot(root
, path
->nodes
[*level
],
5238 path
->slots
[*level
]);
5239 path
->slots
[*level
- 1] = 0;
5243 static int tree_move_next_or_upnext(struct btrfs_root
*root
,
5244 struct btrfs_path
*path
,
5245 int *level
, int root_level
)
5249 nritems
= btrfs_header_nritems(path
->nodes
[*level
]);
5251 path
->slots
[*level
]++;
5253 while (path
->slots
[*level
] >= nritems
) {
5254 if (*level
== root_level
)
5258 path
->slots
[*level
] = 0;
5259 free_extent_buffer(path
->nodes
[*level
]);
5260 path
->nodes
[*level
] = NULL
;
5262 path
->slots
[*level
]++;
5264 nritems
= btrfs_header_nritems(path
->nodes
[*level
]);
5271 * Returns 1 if it had to move up and next. 0 is returned if it moved only next
5274 static int tree_advance(struct btrfs_root
*root
,
5275 struct btrfs_path
*path
,
5276 int *level
, int root_level
,
5278 struct btrfs_key
*key
)
5282 if (*level
== 0 || !allow_down
) {
5283 ret
= tree_move_next_or_upnext(root
, path
, level
, root_level
);
5285 tree_move_down(root
, path
, level
, root_level
);
5290 btrfs_item_key_to_cpu(path
->nodes
[*level
], key
,
5291 path
->slots
[*level
]);
5293 btrfs_node_key_to_cpu(path
->nodes
[*level
], key
,
5294 path
->slots
[*level
]);
5299 static int tree_compare_item(struct btrfs_root
*left_root
,
5300 struct btrfs_path
*left_path
,
5301 struct btrfs_path
*right_path
,
5306 unsigned long off1
, off2
;
5308 len1
= btrfs_item_size_nr(left_path
->nodes
[0], left_path
->slots
[0]);
5309 len2
= btrfs_item_size_nr(right_path
->nodes
[0], right_path
->slots
[0]);
5313 off1
= btrfs_item_ptr_offset(left_path
->nodes
[0], left_path
->slots
[0]);
5314 off2
= btrfs_item_ptr_offset(right_path
->nodes
[0],
5315 right_path
->slots
[0]);
5317 read_extent_buffer(left_path
->nodes
[0], tmp_buf
, off1
, len1
);
5319 cmp
= memcmp_extent_buffer(right_path
->nodes
[0], tmp_buf
, off2
, len1
);
5326 #define ADVANCE_ONLY_NEXT -1
5329 * This function compares two trees and calls the provided callback for
5330 * every changed/new/deleted item it finds.
5331 * If shared tree blocks are encountered, whole subtrees are skipped, making
5332 * the compare pretty fast on snapshotted subvolumes.
5334 * This currently works on commit roots only. As commit roots are read only,
5335 * we don't do any locking. The commit roots are protected with transactions.
5336 * Transactions are ended and rejoined when a commit is tried in between.
5338 * This function checks for modifications done to the trees while comparing.
5339 * If it detects a change, it aborts immediately.
5341 int btrfs_compare_trees(struct btrfs_root
*left_root
,
5342 struct btrfs_root
*right_root
,
5343 btrfs_changed_cb_t changed_cb
, void *ctx
)
5347 struct btrfs_path
*left_path
= NULL
;
5348 struct btrfs_path
*right_path
= NULL
;
5349 struct btrfs_key left_key
;
5350 struct btrfs_key right_key
;
5351 char *tmp_buf
= NULL
;
5352 int left_root_level
;
5353 int right_root_level
;
5356 int left_end_reached
;
5357 int right_end_reached
;
5365 left_path
= btrfs_alloc_path();
5370 right_path
= btrfs_alloc_path();
5376 tmp_buf
= kmalloc(left_root
->nodesize
, GFP_NOFS
);
5382 left_path
->search_commit_root
= 1;
5383 left_path
->skip_locking
= 1;
5384 right_path
->search_commit_root
= 1;
5385 right_path
->skip_locking
= 1;
5388 * Strategy: Go to the first items of both trees. Then do
5390 * If both trees are at level 0
5391 * Compare keys of current items
5392 * If left < right treat left item as new, advance left tree
5394 * If left > right treat right item as deleted, advance right tree
5396 * If left == right do deep compare of items, treat as changed if
5397 * needed, advance both trees and repeat
5398 * If both trees are at the same level but not at level 0
5399 * Compare keys of current nodes/leafs
5400 * If left < right advance left tree and repeat
5401 * If left > right advance right tree and repeat
5402 * If left == right compare blockptrs of the next nodes/leafs
5403 * If they match advance both trees but stay at the same level
5405 * If they don't match advance both trees while allowing to go
5407 * If tree levels are different
5408 * Advance the tree that needs it and repeat
5410 * Advancing a tree means:
5411 * If we are at level 0, try to go to the next slot. If that's not
5412 * possible, go one level up and repeat. Stop when we found a level
5413 * where we could go to the next slot. We may at this point be on a
5416 * If we are not at level 0 and not on shared tree blocks, go one
5419 * If we are not at level 0 and on shared tree blocks, go one slot to
5420 * the right if possible or go up and right.
5423 down_read(&left_root
->fs_info
->commit_root_sem
);
5424 left_level
= btrfs_header_level(left_root
->commit_root
);
5425 left_root_level
= left_level
;
5426 left_path
->nodes
[left_level
] = left_root
->commit_root
;
5427 extent_buffer_get(left_path
->nodes
[left_level
]);
5429 right_level
= btrfs_header_level(right_root
->commit_root
);
5430 right_root_level
= right_level
;
5431 right_path
->nodes
[right_level
] = right_root
->commit_root
;
5432 extent_buffer_get(right_path
->nodes
[right_level
]);
5433 up_read(&left_root
->fs_info
->commit_root_sem
);
5435 if (left_level
== 0)
5436 btrfs_item_key_to_cpu(left_path
->nodes
[left_level
],
5437 &left_key
, left_path
->slots
[left_level
]);
5439 btrfs_node_key_to_cpu(left_path
->nodes
[left_level
],
5440 &left_key
, left_path
->slots
[left_level
]);
5441 if (right_level
== 0)
5442 btrfs_item_key_to_cpu(right_path
->nodes
[right_level
],
5443 &right_key
, right_path
->slots
[right_level
]);
5445 btrfs_node_key_to_cpu(right_path
->nodes
[right_level
],
5446 &right_key
, right_path
->slots
[right_level
]);
5448 left_end_reached
= right_end_reached
= 0;
5449 advance_left
= advance_right
= 0;
5452 if (advance_left
&& !left_end_reached
) {
5453 ret
= tree_advance(left_root
, left_path
, &left_level
,
5455 advance_left
!= ADVANCE_ONLY_NEXT
,
5458 left_end_reached
= ADVANCE
;
5461 if (advance_right
&& !right_end_reached
) {
5462 ret
= tree_advance(right_root
, right_path
, &right_level
,
5464 advance_right
!= ADVANCE_ONLY_NEXT
,
5467 right_end_reached
= ADVANCE
;
5471 if (left_end_reached
&& right_end_reached
) {
5474 } else if (left_end_reached
) {
5475 if (right_level
== 0) {
5476 ret
= changed_cb(left_root
, right_root
,
5477 left_path
, right_path
,
5479 BTRFS_COMPARE_TREE_DELETED
,
5484 advance_right
= ADVANCE
;
5486 } else if (right_end_reached
) {
5487 if (left_level
== 0) {
5488 ret
= changed_cb(left_root
, right_root
,
5489 left_path
, right_path
,
5491 BTRFS_COMPARE_TREE_NEW
,
5496 advance_left
= ADVANCE
;
5500 if (left_level
== 0 && right_level
== 0) {
5501 cmp
= btrfs_comp_cpu_keys(&left_key
, &right_key
);
5503 ret
= changed_cb(left_root
, right_root
,
5504 left_path
, right_path
,
5506 BTRFS_COMPARE_TREE_NEW
,
5510 advance_left
= ADVANCE
;
5511 } else if (cmp
> 0) {
5512 ret
= changed_cb(left_root
, right_root
,
5513 left_path
, right_path
,
5515 BTRFS_COMPARE_TREE_DELETED
,
5519 advance_right
= ADVANCE
;
5521 enum btrfs_compare_tree_result cmp
;
5523 WARN_ON(!extent_buffer_uptodate(left_path
->nodes
[0]));
5524 ret
= tree_compare_item(left_root
, left_path
,
5525 right_path
, tmp_buf
);
5527 cmp
= BTRFS_COMPARE_TREE_CHANGED
;
5529 cmp
= BTRFS_COMPARE_TREE_SAME
;
5530 ret
= changed_cb(left_root
, right_root
,
5531 left_path
, right_path
,
5532 &left_key
, cmp
, ctx
);
5535 advance_left
= ADVANCE
;
5536 advance_right
= ADVANCE
;
5538 } else if (left_level
== right_level
) {
5539 cmp
= btrfs_comp_cpu_keys(&left_key
, &right_key
);
5541 advance_left
= ADVANCE
;
5542 } else if (cmp
> 0) {
5543 advance_right
= ADVANCE
;
5545 left_blockptr
= btrfs_node_blockptr(
5546 left_path
->nodes
[left_level
],
5547 left_path
->slots
[left_level
]);
5548 right_blockptr
= btrfs_node_blockptr(
5549 right_path
->nodes
[right_level
],
5550 right_path
->slots
[right_level
]);
5551 left_gen
= btrfs_node_ptr_generation(
5552 left_path
->nodes
[left_level
],
5553 left_path
->slots
[left_level
]);
5554 right_gen
= btrfs_node_ptr_generation(
5555 right_path
->nodes
[right_level
],
5556 right_path
->slots
[right_level
]);
5557 if (left_blockptr
== right_blockptr
&&
5558 left_gen
== right_gen
) {
5560 * As we're on a shared block, don't
5561 * allow to go deeper.
5563 advance_left
= ADVANCE_ONLY_NEXT
;
5564 advance_right
= ADVANCE_ONLY_NEXT
;
5566 advance_left
= ADVANCE
;
5567 advance_right
= ADVANCE
;
5570 } else if (left_level
< right_level
) {
5571 advance_right
= ADVANCE
;
5573 advance_left
= ADVANCE
;
5578 btrfs_free_path(left_path
);
5579 btrfs_free_path(right_path
);
5585 * this is similar to btrfs_next_leaf, but does not try to preserve
5586 * and fixup the path. It looks for and returns the next key in the
5587 * tree based on the current path and the min_trans parameters.
5589 * 0 is returned if another key is found, < 0 if there are any errors
5590 * and 1 is returned if there are no higher keys in the tree
5592 * path->keep_locks should be set to 1 on the search made before
5593 * calling this function.
5595 int btrfs_find_next_key(struct btrfs_root
*root
, struct btrfs_path
*path
,
5596 struct btrfs_key
*key
, int level
, u64 min_trans
)
5599 struct extent_buffer
*c
;
5601 WARN_ON(!path
->keep_locks
);
5602 while (level
< BTRFS_MAX_LEVEL
) {
5603 if (!path
->nodes
[level
])
5606 slot
= path
->slots
[level
] + 1;
5607 c
= path
->nodes
[level
];
5609 if (slot
>= btrfs_header_nritems(c
)) {
5612 struct btrfs_key cur_key
;
5613 if (level
+ 1 >= BTRFS_MAX_LEVEL
||
5614 !path
->nodes
[level
+ 1])
5617 if (path
->locks
[level
+ 1]) {
5622 slot
= btrfs_header_nritems(c
) - 1;
5624 btrfs_item_key_to_cpu(c
, &cur_key
, slot
);
5626 btrfs_node_key_to_cpu(c
, &cur_key
, slot
);
5628 orig_lowest
= path
->lowest_level
;
5629 btrfs_release_path(path
);
5630 path
->lowest_level
= level
;
5631 ret
= btrfs_search_slot(NULL
, root
, &cur_key
, path
,
5633 path
->lowest_level
= orig_lowest
;
5637 c
= path
->nodes
[level
];
5638 slot
= path
->slots
[level
];
5645 btrfs_item_key_to_cpu(c
, key
, slot
);
5647 u64 gen
= btrfs_node_ptr_generation(c
, slot
);
5649 if (gen
< min_trans
) {
5653 btrfs_node_key_to_cpu(c
, key
, slot
);
5661 * search the tree again to find a leaf with greater keys
5662 * returns 0 if it found something or 1 if there are no greater leaves.
5663 * returns < 0 on io errors.
5665 int btrfs_next_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
)
5667 return btrfs_next_old_leaf(root
, path
, 0);
5670 int btrfs_next_old_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
,
5675 struct extent_buffer
*c
;
5676 struct extent_buffer
*next
;
5677 struct btrfs_key key
;
5680 int old_spinning
= path
->leave_spinning
;
5681 int next_rw_lock
= 0;
5683 nritems
= btrfs_header_nritems(path
->nodes
[0]);
5687 btrfs_item_key_to_cpu(path
->nodes
[0], &key
, nritems
- 1);
5692 btrfs_release_path(path
);
5694 path
->keep_locks
= 1;
5695 path
->leave_spinning
= 1;
5698 ret
= btrfs_search_old_slot(root
, &key
, path
, time_seq
);
5700 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
5701 path
->keep_locks
= 0;
5706 nritems
= btrfs_header_nritems(path
->nodes
[0]);
5708 * by releasing the path above we dropped all our locks. A balance
5709 * could have added more items next to the key that used to be
5710 * at the very end of the block. So, check again here and
5711 * advance the path if there are now more items available.
5713 if (nritems
> 0 && path
->slots
[0] < nritems
- 1) {
5720 * So the above check misses one case:
5721 * - after releasing the path above, someone has removed the item that
5722 * used to be at the very end of the block, and balance between leafs
5723 * gets another one with bigger key.offset to replace it.
5725 * This one should be returned as well, or we can get leaf corruption
5726 * later(esp. in __btrfs_drop_extents()).
5728 * And a bit more explanation about this check,
5729 * with ret > 0, the key isn't found, the path points to the slot
5730 * where it should be inserted, so the path->slots[0] item must be the
5733 if (nritems
> 0 && ret
> 0 && path
->slots
[0] == nritems
- 1) {
5738 while (level
< BTRFS_MAX_LEVEL
) {
5739 if (!path
->nodes
[level
]) {
5744 slot
= path
->slots
[level
] + 1;
5745 c
= path
->nodes
[level
];
5746 if (slot
>= btrfs_header_nritems(c
)) {
5748 if (level
== BTRFS_MAX_LEVEL
) {
5756 btrfs_tree_unlock_rw(next
, next_rw_lock
);
5757 free_extent_buffer(next
);
5761 next_rw_lock
= path
->locks
[level
];
5762 ret
= read_block_for_search(NULL
, root
, path
, &next
, level
,
5768 btrfs_release_path(path
);
5772 if (!path
->skip_locking
) {
5773 ret
= btrfs_try_tree_read_lock(next
);
5774 if (!ret
&& time_seq
) {
5776 * If we don't get the lock, we may be racing
5777 * with push_leaf_left, holding that lock while
5778 * itself waiting for the leaf we've currently
5779 * locked. To solve this situation, we give up
5780 * on our lock and cycle.
5782 free_extent_buffer(next
);
5783 btrfs_release_path(path
);
5788 btrfs_set_path_blocking(path
);
5789 btrfs_tree_read_lock(next
);
5790 btrfs_clear_path_blocking(path
, next
,
5793 next_rw_lock
= BTRFS_READ_LOCK
;
5797 path
->slots
[level
] = slot
;
5800 c
= path
->nodes
[level
];
5801 if (path
->locks
[level
])
5802 btrfs_tree_unlock_rw(c
, path
->locks
[level
]);
5804 free_extent_buffer(c
);
5805 path
->nodes
[level
] = next
;
5806 path
->slots
[level
] = 0;
5807 if (!path
->skip_locking
)
5808 path
->locks
[level
] = next_rw_lock
;
5812 ret
= read_block_for_search(NULL
, root
, path
, &next
, level
,
5818 btrfs_release_path(path
);
5822 if (!path
->skip_locking
) {
5823 ret
= btrfs_try_tree_read_lock(next
);
5825 btrfs_set_path_blocking(path
);
5826 btrfs_tree_read_lock(next
);
5827 btrfs_clear_path_blocking(path
, next
,
5830 next_rw_lock
= BTRFS_READ_LOCK
;
5835 unlock_up(path
, 0, 1, 0, NULL
);
5836 path
->leave_spinning
= old_spinning
;
5838 btrfs_set_path_blocking(path
);
5844 * this uses btrfs_prev_leaf to walk backwards in the tree, and keeps
5845 * searching until it gets past min_objectid or finds an item of 'type'
5847 * returns 0 if something is found, 1 if nothing was found and < 0 on error
5849 int btrfs_previous_item(struct btrfs_root
*root
,
5850 struct btrfs_path
*path
, u64 min_objectid
,
5853 struct btrfs_key found_key
;
5854 struct extent_buffer
*leaf
;
5859 if (path
->slots
[0] == 0) {
5860 btrfs_set_path_blocking(path
);
5861 ret
= btrfs_prev_leaf(root
, path
);
5867 leaf
= path
->nodes
[0];
5868 nritems
= btrfs_header_nritems(leaf
);
5871 if (path
->slots
[0] == nritems
)
5874 btrfs_item_key_to_cpu(leaf
, &found_key
, path
->slots
[0]);
5875 if (found_key
.objectid
< min_objectid
)
5877 if (found_key
.type
== type
)
5879 if (found_key
.objectid
== min_objectid
&&
5880 found_key
.type
< type
)
5887 * search in extent tree to find a previous Metadata/Data extent item with
5890 * returns 0 if something is found, 1 if nothing was found and < 0 on error
5892 int btrfs_previous_extent_item(struct btrfs_root
*root
,
5893 struct btrfs_path
*path
, u64 min_objectid
)
5895 struct btrfs_key found_key
;
5896 struct extent_buffer
*leaf
;
5901 if (path
->slots
[0] == 0) {
5902 btrfs_set_path_blocking(path
);
5903 ret
= btrfs_prev_leaf(root
, path
);
5909 leaf
= path
->nodes
[0];
5910 nritems
= btrfs_header_nritems(leaf
);
5913 if (path
->slots
[0] == nritems
)
5916 btrfs_item_key_to_cpu(leaf
, &found_key
, path
->slots
[0]);
5917 if (found_key
.objectid
< min_objectid
)
5919 if (found_key
.type
== BTRFS_EXTENT_ITEM_KEY
||
5920 found_key
.type
== BTRFS_METADATA_ITEM_KEY
)
5922 if (found_key
.objectid
== min_objectid
&&
5923 found_key
.type
< BTRFS_EXTENT_ITEM_KEY
)