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
);
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
);
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
);
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
);
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
)
2453 struct extent_buffer
*b
= *eb_ret
;
2454 struct extent_buffer
*tmp
;
2457 blocknr
= btrfs_node_blockptr(b
, slot
);
2458 gen
= btrfs_node_ptr_generation(b
, slot
);
2460 tmp
= btrfs_find_tree_block(root
, blocknr
);
2462 /* first we do an atomic uptodate check */
2463 if (btrfs_buffer_uptodate(tmp
, gen
, 1) > 0) {
2468 /* the pages were up to date, but we failed
2469 * the generation number check. Do a full
2470 * read for the generation number that is correct.
2471 * We must do this without dropping locks so
2472 * we can trust our generation number
2474 btrfs_set_path_blocking(p
);
2476 /* now we're allowed to do a blocking uptodate check */
2477 ret
= btrfs_read_buffer(tmp
, gen
);
2482 free_extent_buffer(tmp
);
2483 btrfs_release_path(p
);
2488 * reduce lock contention at high levels
2489 * of the btree by dropping locks before
2490 * we read. Don't release the lock on the current
2491 * level because we need to walk this node to figure
2492 * out which blocks to read.
2494 btrfs_unlock_up_safe(p
, level
+ 1);
2495 btrfs_set_path_blocking(p
);
2497 free_extent_buffer(tmp
);
2499 reada_for_search(root
, p
, level
, slot
, key
->objectid
);
2501 btrfs_release_path(p
);
2504 tmp
= read_tree_block(root
, blocknr
, 0);
2507 * If the read above didn't mark this buffer up to date,
2508 * it will never end up being up to date. Set ret to EIO now
2509 * and give up so that our caller doesn't loop forever
2512 if (!btrfs_buffer_uptodate(tmp
, 0, 0))
2514 free_extent_buffer(tmp
);
2520 * helper function for btrfs_search_slot. This does all of the checks
2521 * for node-level blocks and does any balancing required based on
2524 * If no extra work was required, zero is returned. If we had to
2525 * drop the path, -EAGAIN is returned and btrfs_search_slot must
2529 setup_nodes_for_search(struct btrfs_trans_handle
*trans
,
2530 struct btrfs_root
*root
, struct btrfs_path
*p
,
2531 struct extent_buffer
*b
, int level
, int ins_len
,
2532 int *write_lock_level
)
2535 if ((p
->search_for_split
|| ins_len
> 0) && btrfs_header_nritems(b
) >=
2536 BTRFS_NODEPTRS_PER_BLOCK(root
) - 3) {
2539 if (*write_lock_level
< level
+ 1) {
2540 *write_lock_level
= level
+ 1;
2541 btrfs_release_path(p
);
2545 btrfs_set_path_blocking(p
);
2546 reada_for_balance(root
, p
, level
);
2547 sret
= split_node(trans
, root
, p
, level
);
2548 btrfs_clear_path_blocking(p
, NULL
, 0);
2555 b
= p
->nodes
[level
];
2556 } else if (ins_len
< 0 && btrfs_header_nritems(b
) <
2557 BTRFS_NODEPTRS_PER_BLOCK(root
) / 2) {
2560 if (*write_lock_level
< level
+ 1) {
2561 *write_lock_level
= level
+ 1;
2562 btrfs_release_path(p
);
2566 btrfs_set_path_blocking(p
);
2567 reada_for_balance(root
, p
, level
);
2568 sret
= balance_level(trans
, root
, p
, level
);
2569 btrfs_clear_path_blocking(p
, NULL
, 0);
2575 b
= p
->nodes
[level
];
2577 btrfs_release_path(p
);
2580 BUG_ON(btrfs_header_nritems(b
) == 1);
2590 static void key_search_validate(struct extent_buffer
*b
,
2591 struct btrfs_key
*key
,
2594 #ifdef CONFIG_BTRFS_ASSERT
2595 struct btrfs_disk_key disk_key
;
2597 btrfs_cpu_key_to_disk(&disk_key
, key
);
2600 ASSERT(!memcmp_extent_buffer(b
, &disk_key
,
2601 offsetof(struct btrfs_leaf
, items
[0].key
),
2604 ASSERT(!memcmp_extent_buffer(b
, &disk_key
,
2605 offsetof(struct btrfs_node
, ptrs
[0].key
),
2610 static int key_search(struct extent_buffer
*b
, struct btrfs_key
*key
,
2611 int level
, int *prev_cmp
, int *slot
)
2613 if (*prev_cmp
!= 0) {
2614 *prev_cmp
= bin_search(b
, key
, level
, slot
);
2618 key_search_validate(b
, key
, level
);
2624 int btrfs_find_item(struct btrfs_root
*fs_root
, struct btrfs_path
*found_path
,
2625 u64 iobjectid
, u64 ioff
, u8 key_type
,
2626 struct btrfs_key
*found_key
)
2629 struct btrfs_key key
;
2630 struct extent_buffer
*eb
;
2631 struct btrfs_path
*path
;
2633 key
.type
= key_type
;
2634 key
.objectid
= iobjectid
;
2637 if (found_path
== NULL
) {
2638 path
= btrfs_alloc_path();
2644 ret
= btrfs_search_slot(NULL
, fs_root
, &key
, path
, 0, 0);
2645 if ((ret
< 0) || (found_key
== NULL
)) {
2646 if (path
!= found_path
)
2647 btrfs_free_path(path
);
2651 eb
= path
->nodes
[0];
2652 if (ret
&& path
->slots
[0] >= btrfs_header_nritems(eb
)) {
2653 ret
= btrfs_next_leaf(fs_root
, path
);
2656 eb
= path
->nodes
[0];
2659 btrfs_item_key_to_cpu(eb
, found_key
, path
->slots
[0]);
2660 if (found_key
->type
!= key
.type
||
2661 found_key
->objectid
!= key
.objectid
)
2668 * look for key in the tree. path is filled in with nodes along the way
2669 * if key is found, we return zero and you can find the item in the leaf
2670 * level of the path (level 0)
2672 * If the key isn't found, the path points to the slot where it should
2673 * be inserted, and 1 is returned. If there are other errors during the
2674 * search a negative error number is returned.
2676 * if ins_len > 0, nodes and leaves will be split as we walk down the
2677 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
2680 int btrfs_search_slot(struct btrfs_trans_handle
*trans
, struct btrfs_root
2681 *root
, struct btrfs_key
*key
, struct btrfs_path
*p
, int
2684 struct extent_buffer
*b
;
2689 int lowest_unlock
= 1;
2691 /* everything at write_lock_level or lower must be write locked */
2692 int write_lock_level
= 0;
2693 u8 lowest_level
= 0;
2694 int min_write_lock_level
;
2697 lowest_level
= p
->lowest_level
;
2698 WARN_ON(lowest_level
&& ins_len
> 0);
2699 WARN_ON(p
->nodes
[0] != NULL
);
2700 BUG_ON(!cow
&& ins_len
);
2705 /* when we are removing items, we might have to go up to level
2706 * two as we update tree pointers Make sure we keep write
2707 * for those levels as well
2709 write_lock_level
= 2;
2710 } else if (ins_len
> 0) {
2712 * for inserting items, make sure we have a write lock on
2713 * level 1 so we can update keys
2715 write_lock_level
= 1;
2719 write_lock_level
= -1;
2721 if (cow
&& (p
->keep_locks
|| p
->lowest_level
))
2722 write_lock_level
= BTRFS_MAX_LEVEL
;
2724 min_write_lock_level
= write_lock_level
;
2729 * we try very hard to do read locks on the root
2731 root_lock
= BTRFS_READ_LOCK
;
2733 if (p
->search_commit_root
) {
2735 * the commit roots are read only
2736 * so we always do read locks
2738 if (p
->need_commit_sem
)
2739 down_read(&root
->fs_info
->commit_root_sem
);
2740 b
= root
->commit_root
;
2741 extent_buffer_get(b
);
2742 level
= btrfs_header_level(b
);
2743 if (p
->need_commit_sem
)
2744 up_read(&root
->fs_info
->commit_root_sem
);
2745 if (!p
->skip_locking
)
2746 btrfs_tree_read_lock(b
);
2748 if (p
->skip_locking
) {
2749 b
= btrfs_root_node(root
);
2750 level
= btrfs_header_level(b
);
2752 /* we don't know the level of the root node
2753 * until we actually have it read locked
2755 b
= btrfs_read_lock_root_node(root
);
2756 level
= btrfs_header_level(b
);
2757 if (level
<= write_lock_level
) {
2758 /* whoops, must trade for write lock */
2759 btrfs_tree_read_unlock(b
);
2760 free_extent_buffer(b
);
2761 b
= btrfs_lock_root_node(root
);
2762 root_lock
= BTRFS_WRITE_LOCK
;
2764 /* the level might have changed, check again */
2765 level
= btrfs_header_level(b
);
2769 p
->nodes
[level
] = b
;
2770 if (!p
->skip_locking
)
2771 p
->locks
[level
] = root_lock
;
2774 level
= btrfs_header_level(b
);
2777 * setup the path here so we can release it under lock
2778 * contention with the cow code
2782 * if we don't really need to cow this block
2783 * then we don't want to set the path blocking,
2784 * so we test it here
2786 if (!should_cow_block(trans
, root
, b
))
2790 * must have write locks on this node and the
2793 if (level
> write_lock_level
||
2794 (level
+ 1 > write_lock_level
&&
2795 level
+ 1 < BTRFS_MAX_LEVEL
&&
2796 p
->nodes
[level
+ 1])) {
2797 write_lock_level
= level
+ 1;
2798 btrfs_release_path(p
);
2802 btrfs_set_path_blocking(p
);
2803 err
= btrfs_cow_block(trans
, root
, b
,
2804 p
->nodes
[level
+ 1],
2805 p
->slots
[level
+ 1], &b
);
2812 p
->nodes
[level
] = b
;
2813 btrfs_clear_path_blocking(p
, NULL
, 0);
2816 * we have a lock on b and as long as we aren't changing
2817 * the tree, there is no way to for the items in b to change.
2818 * It is safe to drop the lock on our parent before we
2819 * go through the expensive btree search on b.
2821 * If we're inserting or deleting (ins_len != 0), then we might
2822 * be changing slot zero, which may require changing the parent.
2823 * So, we can't drop the lock until after we know which slot
2824 * we're operating on.
2826 if (!ins_len
&& !p
->keep_locks
) {
2829 if (u
< BTRFS_MAX_LEVEL
&& p
->locks
[u
]) {
2830 btrfs_tree_unlock_rw(p
->nodes
[u
], p
->locks
[u
]);
2835 ret
= key_search(b
, key
, level
, &prev_cmp
, &slot
);
2839 if (ret
&& slot
> 0) {
2843 p
->slots
[level
] = slot
;
2844 err
= setup_nodes_for_search(trans
, root
, p
, b
, level
,
2845 ins_len
, &write_lock_level
);
2852 b
= p
->nodes
[level
];
2853 slot
= p
->slots
[level
];
2856 * slot 0 is special, if we change the key
2857 * we have to update the parent pointer
2858 * which means we must have a write lock
2861 if (slot
== 0 && ins_len
&&
2862 write_lock_level
< level
+ 1) {
2863 write_lock_level
= level
+ 1;
2864 btrfs_release_path(p
);
2868 unlock_up(p
, level
, lowest_unlock
,
2869 min_write_lock_level
, &write_lock_level
);
2871 if (level
== lowest_level
) {
2877 err
= read_block_for_search(trans
, root
, p
,
2878 &b
, level
, slot
, key
, 0);
2886 if (!p
->skip_locking
) {
2887 level
= btrfs_header_level(b
);
2888 if (level
<= write_lock_level
) {
2889 err
= btrfs_try_tree_write_lock(b
);
2891 btrfs_set_path_blocking(p
);
2893 btrfs_clear_path_blocking(p
, b
,
2896 p
->locks
[level
] = BTRFS_WRITE_LOCK
;
2898 err
= btrfs_try_tree_read_lock(b
);
2900 btrfs_set_path_blocking(p
);
2901 btrfs_tree_read_lock(b
);
2902 btrfs_clear_path_blocking(p
, b
,
2905 p
->locks
[level
] = BTRFS_READ_LOCK
;
2907 p
->nodes
[level
] = b
;
2910 p
->slots
[level
] = slot
;
2912 btrfs_leaf_free_space(root
, b
) < ins_len
) {
2913 if (write_lock_level
< 1) {
2914 write_lock_level
= 1;
2915 btrfs_release_path(p
);
2919 btrfs_set_path_blocking(p
);
2920 err
= split_leaf(trans
, root
, key
,
2921 p
, ins_len
, ret
== 0);
2922 btrfs_clear_path_blocking(p
, NULL
, 0);
2930 if (!p
->search_for_split
)
2931 unlock_up(p
, level
, lowest_unlock
,
2932 min_write_lock_level
, &write_lock_level
);
2939 * we don't really know what they plan on doing with the path
2940 * from here on, so for now just mark it as blocking
2942 if (!p
->leave_spinning
)
2943 btrfs_set_path_blocking(p
);
2945 btrfs_release_path(p
);
2950 * Like btrfs_search_slot, this looks for a key in the given tree. It uses the
2951 * current state of the tree together with the operations recorded in the tree
2952 * modification log to search for the key in a previous version of this tree, as
2953 * denoted by the time_seq parameter.
2955 * Naturally, there is no support for insert, delete or cow operations.
2957 * The resulting path and return value will be set up as if we called
2958 * btrfs_search_slot at that point in time with ins_len and cow both set to 0.
2960 int btrfs_search_old_slot(struct btrfs_root
*root
, struct btrfs_key
*key
,
2961 struct btrfs_path
*p
, u64 time_seq
)
2963 struct extent_buffer
*b
;
2968 int lowest_unlock
= 1;
2969 u8 lowest_level
= 0;
2972 lowest_level
= p
->lowest_level
;
2973 WARN_ON(p
->nodes
[0] != NULL
);
2975 if (p
->search_commit_root
) {
2977 return btrfs_search_slot(NULL
, root
, key
, p
, 0, 0);
2981 b
= get_old_root(root
, time_seq
);
2982 level
= btrfs_header_level(b
);
2983 p
->locks
[level
] = BTRFS_READ_LOCK
;
2986 level
= btrfs_header_level(b
);
2987 p
->nodes
[level
] = b
;
2988 btrfs_clear_path_blocking(p
, NULL
, 0);
2991 * we have a lock on b and as long as we aren't changing
2992 * the tree, there is no way to for the items in b to change.
2993 * It is safe to drop the lock on our parent before we
2994 * go through the expensive btree search on b.
2996 btrfs_unlock_up_safe(p
, level
+ 1);
2999 * Since we can unwind eb's we want to do a real search every
3003 ret
= key_search(b
, key
, level
, &prev_cmp
, &slot
);
3007 if (ret
&& slot
> 0) {
3011 p
->slots
[level
] = slot
;
3012 unlock_up(p
, level
, lowest_unlock
, 0, NULL
);
3014 if (level
== lowest_level
) {
3020 err
= read_block_for_search(NULL
, root
, p
, &b
, level
,
3021 slot
, key
, time_seq
);
3029 level
= btrfs_header_level(b
);
3030 err
= btrfs_try_tree_read_lock(b
);
3032 btrfs_set_path_blocking(p
);
3033 btrfs_tree_read_lock(b
);
3034 btrfs_clear_path_blocking(p
, b
,
3037 b
= tree_mod_log_rewind(root
->fs_info
, p
, b
, time_seq
);
3042 p
->locks
[level
] = BTRFS_READ_LOCK
;
3043 p
->nodes
[level
] = b
;
3045 p
->slots
[level
] = slot
;
3046 unlock_up(p
, level
, lowest_unlock
, 0, NULL
);
3052 if (!p
->leave_spinning
)
3053 btrfs_set_path_blocking(p
);
3055 btrfs_release_path(p
);
3061 * helper to use instead of search slot if no exact match is needed but
3062 * instead the next or previous item should be returned.
3063 * When find_higher is true, the next higher item is returned, the next lower
3065 * When return_any and find_higher are both true, and no higher item is found,
3066 * return the next lower instead.
3067 * When return_any is true and find_higher is false, and no lower item is found,
3068 * return the next higher instead.
3069 * It returns 0 if any item is found, 1 if none is found (tree empty), and
3072 int btrfs_search_slot_for_read(struct btrfs_root
*root
,
3073 struct btrfs_key
*key
, struct btrfs_path
*p
,
3074 int find_higher
, int return_any
)
3077 struct extent_buffer
*leaf
;
3080 ret
= btrfs_search_slot(NULL
, root
, key
, p
, 0, 0);
3084 * a return value of 1 means the path is at the position where the
3085 * item should be inserted. Normally this is the next bigger item,
3086 * but in case the previous item is the last in a leaf, path points
3087 * to the first free slot in the previous leaf, i.e. at an invalid
3093 if (p
->slots
[0] >= btrfs_header_nritems(leaf
)) {
3094 ret
= btrfs_next_leaf(root
, p
);
3100 * no higher item found, return the next
3105 btrfs_release_path(p
);
3109 if (p
->slots
[0] == 0) {
3110 ret
= btrfs_prev_leaf(root
, p
);
3115 if (p
->slots
[0] == btrfs_header_nritems(leaf
))
3122 * no lower item found, return the next
3127 btrfs_release_path(p
);
3137 * adjust the pointers going up the tree, starting at level
3138 * making sure the right key of each node is points to 'key'.
3139 * This is used after shifting pointers to the left, so it stops
3140 * fixing up pointers when a given leaf/node is not in slot 0 of the
3144 static void fixup_low_keys(struct btrfs_root
*root
, struct btrfs_path
*path
,
3145 struct btrfs_disk_key
*key
, int level
)
3148 struct extent_buffer
*t
;
3150 for (i
= level
; i
< BTRFS_MAX_LEVEL
; i
++) {
3151 int tslot
= path
->slots
[i
];
3152 if (!path
->nodes
[i
])
3155 tree_mod_log_set_node_key(root
->fs_info
, t
, tslot
, 1);
3156 btrfs_set_node_key(t
, key
, tslot
);
3157 btrfs_mark_buffer_dirty(path
->nodes
[i
]);
3166 * This function isn't completely safe. It's the caller's responsibility
3167 * that the new key won't break the order
3169 void btrfs_set_item_key_safe(struct btrfs_root
*root
, struct btrfs_path
*path
,
3170 struct btrfs_key
*new_key
)
3172 struct btrfs_disk_key disk_key
;
3173 struct extent_buffer
*eb
;
3176 eb
= path
->nodes
[0];
3177 slot
= path
->slots
[0];
3179 btrfs_item_key(eb
, &disk_key
, slot
- 1);
3180 BUG_ON(comp_keys(&disk_key
, new_key
) >= 0);
3182 if (slot
< btrfs_header_nritems(eb
) - 1) {
3183 btrfs_item_key(eb
, &disk_key
, slot
+ 1);
3184 BUG_ON(comp_keys(&disk_key
, new_key
) <= 0);
3187 btrfs_cpu_key_to_disk(&disk_key
, new_key
);
3188 btrfs_set_item_key(eb
, &disk_key
, slot
);
3189 btrfs_mark_buffer_dirty(eb
);
3191 fixup_low_keys(root
, path
, &disk_key
, 1);
3195 * try to push data from one node into the next node left in the
3198 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
3199 * error, and > 0 if there was no room in the left hand block.
3201 static int push_node_left(struct btrfs_trans_handle
*trans
,
3202 struct btrfs_root
*root
, struct extent_buffer
*dst
,
3203 struct extent_buffer
*src
, int empty
)
3210 src_nritems
= btrfs_header_nritems(src
);
3211 dst_nritems
= btrfs_header_nritems(dst
);
3212 push_items
= BTRFS_NODEPTRS_PER_BLOCK(root
) - dst_nritems
;
3213 WARN_ON(btrfs_header_generation(src
) != trans
->transid
);
3214 WARN_ON(btrfs_header_generation(dst
) != trans
->transid
);
3216 if (!empty
&& src_nritems
<= 8)
3219 if (push_items
<= 0)
3223 push_items
= min(src_nritems
, push_items
);
3224 if (push_items
< src_nritems
) {
3225 /* leave at least 8 pointers in the node if
3226 * we aren't going to empty it
3228 if (src_nritems
- push_items
< 8) {
3229 if (push_items
<= 8)
3235 push_items
= min(src_nritems
- 8, push_items
);
3237 ret
= tree_mod_log_eb_copy(root
->fs_info
, dst
, src
, dst_nritems
, 0,
3240 btrfs_abort_transaction(trans
, root
, ret
);
3243 copy_extent_buffer(dst
, src
,
3244 btrfs_node_key_ptr_offset(dst_nritems
),
3245 btrfs_node_key_ptr_offset(0),
3246 push_items
* sizeof(struct btrfs_key_ptr
));
3248 if (push_items
< src_nritems
) {
3250 * don't call tree_mod_log_eb_move here, key removal was already
3251 * fully logged by tree_mod_log_eb_copy above.
3253 memmove_extent_buffer(src
, btrfs_node_key_ptr_offset(0),
3254 btrfs_node_key_ptr_offset(push_items
),
3255 (src_nritems
- push_items
) *
3256 sizeof(struct btrfs_key_ptr
));
3258 btrfs_set_header_nritems(src
, src_nritems
- push_items
);
3259 btrfs_set_header_nritems(dst
, dst_nritems
+ push_items
);
3260 btrfs_mark_buffer_dirty(src
);
3261 btrfs_mark_buffer_dirty(dst
);
3267 * try to push data from one node into the next node right in the
3270 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
3271 * error, and > 0 if there was no room in the right hand block.
3273 * this will only push up to 1/2 the contents of the left node over
3275 static int balance_node_right(struct btrfs_trans_handle
*trans
,
3276 struct btrfs_root
*root
,
3277 struct extent_buffer
*dst
,
3278 struct extent_buffer
*src
)
3286 WARN_ON(btrfs_header_generation(src
) != trans
->transid
);
3287 WARN_ON(btrfs_header_generation(dst
) != trans
->transid
);
3289 src_nritems
= btrfs_header_nritems(src
);
3290 dst_nritems
= btrfs_header_nritems(dst
);
3291 push_items
= BTRFS_NODEPTRS_PER_BLOCK(root
) - dst_nritems
;
3292 if (push_items
<= 0)
3295 if (src_nritems
< 4)
3298 max_push
= src_nritems
/ 2 + 1;
3299 /* don't try to empty the node */
3300 if (max_push
>= src_nritems
)
3303 if (max_push
< push_items
)
3304 push_items
= max_push
;
3306 tree_mod_log_eb_move(root
->fs_info
, dst
, push_items
, 0, dst_nritems
);
3307 memmove_extent_buffer(dst
, btrfs_node_key_ptr_offset(push_items
),
3308 btrfs_node_key_ptr_offset(0),
3310 sizeof(struct btrfs_key_ptr
));
3312 ret
= tree_mod_log_eb_copy(root
->fs_info
, dst
, src
, 0,
3313 src_nritems
- push_items
, push_items
);
3315 btrfs_abort_transaction(trans
, root
, ret
);
3318 copy_extent_buffer(dst
, src
,
3319 btrfs_node_key_ptr_offset(0),
3320 btrfs_node_key_ptr_offset(src_nritems
- push_items
),
3321 push_items
* sizeof(struct btrfs_key_ptr
));
3323 btrfs_set_header_nritems(src
, src_nritems
- push_items
);
3324 btrfs_set_header_nritems(dst
, dst_nritems
+ push_items
);
3326 btrfs_mark_buffer_dirty(src
);
3327 btrfs_mark_buffer_dirty(dst
);
3333 * helper function to insert a new root level in the tree.
3334 * A new node is allocated, and a single item is inserted to
3335 * point to the existing root
3337 * returns zero on success or < 0 on failure.
3339 static noinline
int insert_new_root(struct btrfs_trans_handle
*trans
,
3340 struct btrfs_root
*root
,
3341 struct btrfs_path
*path
, int level
)
3344 struct extent_buffer
*lower
;
3345 struct extent_buffer
*c
;
3346 struct extent_buffer
*old
;
3347 struct btrfs_disk_key lower_key
;
3349 BUG_ON(path
->nodes
[level
]);
3350 BUG_ON(path
->nodes
[level
-1] != root
->node
);
3352 lower
= path
->nodes
[level
-1];
3354 btrfs_item_key(lower
, &lower_key
, 0);
3356 btrfs_node_key(lower
, &lower_key
, 0);
3358 c
= btrfs_alloc_free_block(trans
, root
, root
->nodesize
, 0,
3359 root
->root_key
.objectid
, &lower_key
,
3360 level
, root
->node
->start
, 0);
3364 root_add_used(root
, root
->nodesize
);
3366 memset_extent_buffer(c
, 0, 0, sizeof(struct btrfs_header
));
3367 btrfs_set_header_nritems(c
, 1);
3368 btrfs_set_header_level(c
, level
);
3369 btrfs_set_header_bytenr(c
, c
->start
);
3370 btrfs_set_header_generation(c
, trans
->transid
);
3371 btrfs_set_header_backref_rev(c
, BTRFS_MIXED_BACKREF_REV
);
3372 btrfs_set_header_owner(c
, root
->root_key
.objectid
);
3374 write_extent_buffer(c
, root
->fs_info
->fsid
, btrfs_header_fsid(),
3377 write_extent_buffer(c
, root
->fs_info
->chunk_tree_uuid
,
3378 btrfs_header_chunk_tree_uuid(c
), BTRFS_UUID_SIZE
);
3380 btrfs_set_node_key(c
, &lower_key
, 0);
3381 btrfs_set_node_blockptr(c
, 0, lower
->start
);
3382 lower_gen
= btrfs_header_generation(lower
);
3383 WARN_ON(lower_gen
!= trans
->transid
);
3385 btrfs_set_node_ptr_generation(c
, 0, lower_gen
);
3387 btrfs_mark_buffer_dirty(c
);
3390 tree_mod_log_set_root_pointer(root
, c
, 0);
3391 rcu_assign_pointer(root
->node
, c
);
3393 /* the super has an extra ref to root->node */
3394 free_extent_buffer(old
);
3396 add_root_to_dirty_list(root
);
3397 extent_buffer_get(c
);
3398 path
->nodes
[level
] = c
;
3399 path
->locks
[level
] = BTRFS_WRITE_LOCK
;
3400 path
->slots
[level
] = 0;
3405 * worker function to insert a single pointer in a node.
3406 * the node should have enough room for the pointer already
3408 * slot and level indicate where you want the key to go, and
3409 * blocknr is the block the key points to.
3411 static void insert_ptr(struct btrfs_trans_handle
*trans
,
3412 struct btrfs_root
*root
, struct btrfs_path
*path
,
3413 struct btrfs_disk_key
*key
, u64 bytenr
,
3414 int slot
, int level
)
3416 struct extent_buffer
*lower
;
3420 BUG_ON(!path
->nodes
[level
]);
3421 btrfs_assert_tree_locked(path
->nodes
[level
]);
3422 lower
= path
->nodes
[level
];
3423 nritems
= btrfs_header_nritems(lower
);
3424 BUG_ON(slot
> nritems
);
3425 BUG_ON(nritems
== BTRFS_NODEPTRS_PER_BLOCK(root
));
3426 if (slot
!= nritems
) {
3428 tree_mod_log_eb_move(root
->fs_info
, lower
, slot
+ 1,
3429 slot
, nritems
- slot
);
3430 memmove_extent_buffer(lower
,
3431 btrfs_node_key_ptr_offset(slot
+ 1),
3432 btrfs_node_key_ptr_offset(slot
),
3433 (nritems
- slot
) * sizeof(struct btrfs_key_ptr
));
3436 ret
= tree_mod_log_insert_key(root
->fs_info
, lower
, slot
,
3437 MOD_LOG_KEY_ADD
, GFP_NOFS
);
3440 btrfs_set_node_key(lower
, key
, slot
);
3441 btrfs_set_node_blockptr(lower
, slot
, bytenr
);
3442 WARN_ON(trans
->transid
== 0);
3443 btrfs_set_node_ptr_generation(lower
, slot
, trans
->transid
);
3444 btrfs_set_header_nritems(lower
, nritems
+ 1);
3445 btrfs_mark_buffer_dirty(lower
);
3449 * split the node at the specified level in path in two.
3450 * The path is corrected to point to the appropriate node after the split
3452 * Before splitting this tries to make some room in the node by pushing
3453 * left and right, if either one works, it returns right away.
3455 * returns 0 on success and < 0 on failure
3457 static noinline
int split_node(struct btrfs_trans_handle
*trans
,
3458 struct btrfs_root
*root
,
3459 struct btrfs_path
*path
, int level
)
3461 struct extent_buffer
*c
;
3462 struct extent_buffer
*split
;
3463 struct btrfs_disk_key disk_key
;
3468 c
= path
->nodes
[level
];
3469 WARN_ON(btrfs_header_generation(c
) != trans
->transid
);
3470 if (c
== root
->node
) {
3472 * trying to split the root, lets make a new one
3474 * tree mod log: We don't log_removal old root in
3475 * insert_new_root, because that root buffer will be kept as a
3476 * normal node. We are going to log removal of half of the
3477 * elements below with tree_mod_log_eb_copy. We're holding a
3478 * tree lock on the buffer, which is why we cannot race with
3479 * other tree_mod_log users.
3481 ret
= insert_new_root(trans
, root
, path
, level
+ 1);
3485 ret
= push_nodes_for_insert(trans
, root
, path
, level
);
3486 c
= path
->nodes
[level
];
3487 if (!ret
&& btrfs_header_nritems(c
) <
3488 BTRFS_NODEPTRS_PER_BLOCK(root
) - 3)
3494 c_nritems
= btrfs_header_nritems(c
);
3495 mid
= (c_nritems
+ 1) / 2;
3496 btrfs_node_key(c
, &disk_key
, mid
);
3498 split
= btrfs_alloc_free_block(trans
, root
, root
->nodesize
, 0,
3499 root
->root_key
.objectid
,
3500 &disk_key
, level
, c
->start
, 0);
3502 return PTR_ERR(split
);
3504 root_add_used(root
, root
->nodesize
);
3506 memset_extent_buffer(split
, 0, 0, sizeof(struct btrfs_header
));
3507 btrfs_set_header_level(split
, btrfs_header_level(c
));
3508 btrfs_set_header_bytenr(split
, split
->start
);
3509 btrfs_set_header_generation(split
, trans
->transid
);
3510 btrfs_set_header_backref_rev(split
, BTRFS_MIXED_BACKREF_REV
);
3511 btrfs_set_header_owner(split
, root
->root_key
.objectid
);
3512 write_extent_buffer(split
, root
->fs_info
->fsid
,
3513 btrfs_header_fsid(), BTRFS_FSID_SIZE
);
3514 write_extent_buffer(split
, root
->fs_info
->chunk_tree_uuid
,
3515 btrfs_header_chunk_tree_uuid(split
),
3518 ret
= tree_mod_log_eb_copy(root
->fs_info
, split
, c
, 0,
3519 mid
, c_nritems
- mid
);
3521 btrfs_abort_transaction(trans
, root
, ret
);
3524 copy_extent_buffer(split
, c
,
3525 btrfs_node_key_ptr_offset(0),
3526 btrfs_node_key_ptr_offset(mid
),
3527 (c_nritems
- mid
) * sizeof(struct btrfs_key_ptr
));
3528 btrfs_set_header_nritems(split
, c_nritems
- mid
);
3529 btrfs_set_header_nritems(c
, mid
);
3532 btrfs_mark_buffer_dirty(c
);
3533 btrfs_mark_buffer_dirty(split
);
3535 insert_ptr(trans
, root
, path
, &disk_key
, split
->start
,
3536 path
->slots
[level
+ 1] + 1, level
+ 1);
3538 if (path
->slots
[level
] >= mid
) {
3539 path
->slots
[level
] -= mid
;
3540 btrfs_tree_unlock(c
);
3541 free_extent_buffer(c
);
3542 path
->nodes
[level
] = split
;
3543 path
->slots
[level
+ 1] += 1;
3545 btrfs_tree_unlock(split
);
3546 free_extent_buffer(split
);
3552 * how many bytes are required to store the items in a leaf. start
3553 * and nr indicate which items in the leaf to check. This totals up the
3554 * space used both by the item structs and the item data
3556 static int leaf_space_used(struct extent_buffer
*l
, int start
, int nr
)
3558 struct btrfs_item
*start_item
;
3559 struct btrfs_item
*end_item
;
3560 struct btrfs_map_token token
;
3562 int nritems
= btrfs_header_nritems(l
);
3563 int end
= min(nritems
, start
+ nr
) - 1;
3567 btrfs_init_map_token(&token
);
3568 start_item
= btrfs_item_nr(start
);
3569 end_item
= btrfs_item_nr(end
);
3570 data_len
= btrfs_token_item_offset(l
, start_item
, &token
) +
3571 btrfs_token_item_size(l
, start_item
, &token
);
3572 data_len
= data_len
- btrfs_token_item_offset(l
, end_item
, &token
);
3573 data_len
+= sizeof(struct btrfs_item
) * nr
;
3574 WARN_ON(data_len
< 0);
3579 * The space between the end of the leaf items and
3580 * the start of the leaf data. IOW, how much room
3581 * the leaf has left for both items and data
3583 noinline
int btrfs_leaf_free_space(struct btrfs_root
*root
,
3584 struct extent_buffer
*leaf
)
3586 int nritems
= btrfs_header_nritems(leaf
);
3588 ret
= BTRFS_LEAF_DATA_SIZE(root
) - leaf_space_used(leaf
, 0, nritems
);
3590 btrfs_crit(root
->fs_info
,
3591 "leaf free space ret %d, leaf data size %lu, used %d nritems %d",
3592 ret
, (unsigned long) BTRFS_LEAF_DATA_SIZE(root
),
3593 leaf_space_used(leaf
, 0, nritems
), nritems
);
3599 * min slot controls the lowest index we're willing to push to the
3600 * right. We'll push up to and including min_slot, but no lower
3602 static noinline
int __push_leaf_right(struct btrfs_trans_handle
*trans
,
3603 struct btrfs_root
*root
,
3604 struct btrfs_path
*path
,
3605 int data_size
, int empty
,
3606 struct extent_buffer
*right
,
3607 int free_space
, u32 left_nritems
,
3610 struct extent_buffer
*left
= path
->nodes
[0];
3611 struct extent_buffer
*upper
= path
->nodes
[1];
3612 struct btrfs_map_token token
;
3613 struct btrfs_disk_key disk_key
;
3618 struct btrfs_item
*item
;
3624 btrfs_init_map_token(&token
);
3629 nr
= max_t(u32
, 1, min_slot
);
3631 if (path
->slots
[0] >= left_nritems
)
3632 push_space
+= data_size
;
3634 slot
= path
->slots
[1];
3635 i
= left_nritems
- 1;
3637 item
= btrfs_item_nr(i
);
3639 if (!empty
&& push_items
> 0) {
3640 if (path
->slots
[0] > i
)
3642 if (path
->slots
[0] == i
) {
3643 int space
= btrfs_leaf_free_space(root
, left
);
3644 if (space
+ push_space
* 2 > free_space
)
3649 if (path
->slots
[0] == i
)
3650 push_space
+= data_size
;
3652 this_item_size
= btrfs_item_size(left
, item
);
3653 if (this_item_size
+ sizeof(*item
) + push_space
> free_space
)
3657 push_space
+= this_item_size
+ sizeof(*item
);
3663 if (push_items
== 0)
3666 WARN_ON(!empty
&& push_items
== left_nritems
);
3668 /* push left to right */
3669 right_nritems
= btrfs_header_nritems(right
);
3671 push_space
= btrfs_item_end_nr(left
, left_nritems
- push_items
);
3672 push_space
-= leaf_data_end(root
, left
);
3674 /* make room in the right data area */
3675 data_end
= leaf_data_end(root
, right
);
3676 memmove_extent_buffer(right
,
3677 btrfs_leaf_data(right
) + data_end
- push_space
,
3678 btrfs_leaf_data(right
) + data_end
,
3679 BTRFS_LEAF_DATA_SIZE(root
) - data_end
);
3681 /* copy from the left data area */
3682 copy_extent_buffer(right
, left
, btrfs_leaf_data(right
) +
3683 BTRFS_LEAF_DATA_SIZE(root
) - push_space
,
3684 btrfs_leaf_data(left
) + leaf_data_end(root
, left
),
3687 memmove_extent_buffer(right
, btrfs_item_nr_offset(push_items
),
3688 btrfs_item_nr_offset(0),
3689 right_nritems
* sizeof(struct btrfs_item
));
3691 /* copy the items from left to right */
3692 copy_extent_buffer(right
, left
, btrfs_item_nr_offset(0),
3693 btrfs_item_nr_offset(left_nritems
- push_items
),
3694 push_items
* sizeof(struct btrfs_item
));
3696 /* update the item pointers */
3697 right_nritems
+= push_items
;
3698 btrfs_set_header_nritems(right
, right_nritems
);
3699 push_space
= BTRFS_LEAF_DATA_SIZE(root
);
3700 for (i
= 0; i
< right_nritems
; i
++) {
3701 item
= btrfs_item_nr(i
);
3702 push_space
-= btrfs_token_item_size(right
, item
, &token
);
3703 btrfs_set_token_item_offset(right
, item
, push_space
, &token
);
3706 left_nritems
-= push_items
;
3707 btrfs_set_header_nritems(left
, left_nritems
);
3710 btrfs_mark_buffer_dirty(left
);
3712 clean_tree_block(trans
, root
, left
);
3714 btrfs_mark_buffer_dirty(right
);
3716 btrfs_item_key(right
, &disk_key
, 0);
3717 btrfs_set_node_key(upper
, &disk_key
, slot
+ 1);
3718 btrfs_mark_buffer_dirty(upper
);
3720 /* then fixup the leaf pointer in the path */
3721 if (path
->slots
[0] >= left_nritems
) {
3722 path
->slots
[0] -= left_nritems
;
3723 if (btrfs_header_nritems(path
->nodes
[0]) == 0)
3724 clean_tree_block(trans
, root
, path
->nodes
[0]);
3725 btrfs_tree_unlock(path
->nodes
[0]);
3726 free_extent_buffer(path
->nodes
[0]);
3727 path
->nodes
[0] = right
;
3728 path
->slots
[1] += 1;
3730 btrfs_tree_unlock(right
);
3731 free_extent_buffer(right
);
3736 btrfs_tree_unlock(right
);
3737 free_extent_buffer(right
);
3742 * push some data in the path leaf to the right, trying to free up at
3743 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3745 * returns 1 if the push failed because the other node didn't have enough
3746 * room, 0 if everything worked out and < 0 if there were major errors.
3748 * this will push starting from min_slot to the end of the leaf. It won't
3749 * push any slot lower than min_slot
3751 static int push_leaf_right(struct btrfs_trans_handle
*trans
, struct btrfs_root
3752 *root
, struct btrfs_path
*path
,
3753 int min_data_size
, int data_size
,
3754 int empty
, u32 min_slot
)
3756 struct extent_buffer
*left
= path
->nodes
[0];
3757 struct extent_buffer
*right
;
3758 struct extent_buffer
*upper
;
3764 if (!path
->nodes
[1])
3767 slot
= path
->slots
[1];
3768 upper
= path
->nodes
[1];
3769 if (slot
>= btrfs_header_nritems(upper
) - 1)
3772 btrfs_assert_tree_locked(path
->nodes
[1]);
3774 right
= read_node_slot(root
, upper
, slot
+ 1);
3778 btrfs_tree_lock(right
);
3779 btrfs_set_lock_blocking(right
);
3781 free_space
= btrfs_leaf_free_space(root
, right
);
3782 if (free_space
< data_size
)
3785 /* cow and double check */
3786 ret
= btrfs_cow_block(trans
, root
, right
, upper
,
3791 free_space
= btrfs_leaf_free_space(root
, right
);
3792 if (free_space
< data_size
)
3795 left_nritems
= btrfs_header_nritems(left
);
3796 if (left_nritems
== 0)
3799 if (path
->slots
[0] == left_nritems
&& !empty
) {
3800 /* Key greater than all keys in the leaf, right neighbor has
3801 * enough room for it and we're not emptying our leaf to delete
3802 * it, therefore use right neighbor to insert the new item and
3803 * no need to touch/dirty our left leaft. */
3804 btrfs_tree_unlock(left
);
3805 free_extent_buffer(left
);
3806 path
->nodes
[0] = right
;
3812 return __push_leaf_right(trans
, root
, path
, min_data_size
, empty
,
3813 right
, free_space
, left_nritems
, min_slot
);
3815 btrfs_tree_unlock(right
);
3816 free_extent_buffer(right
);
3821 * push some data in the path leaf to the left, trying to free up at
3822 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3824 * max_slot can put a limit on how far into the leaf we'll push items. The
3825 * item at 'max_slot' won't be touched. Use (u32)-1 to make us do all the
3828 static noinline
int __push_leaf_left(struct btrfs_trans_handle
*trans
,
3829 struct btrfs_root
*root
,
3830 struct btrfs_path
*path
, int data_size
,
3831 int empty
, struct extent_buffer
*left
,
3832 int free_space
, u32 right_nritems
,
3835 struct btrfs_disk_key disk_key
;
3836 struct extent_buffer
*right
= path
->nodes
[0];
3840 struct btrfs_item
*item
;
3841 u32 old_left_nritems
;
3845 u32 old_left_item_size
;
3846 struct btrfs_map_token token
;
3848 btrfs_init_map_token(&token
);
3851 nr
= min(right_nritems
, max_slot
);
3853 nr
= min(right_nritems
- 1, max_slot
);
3855 for (i
= 0; i
< nr
; i
++) {
3856 item
= btrfs_item_nr(i
);
3858 if (!empty
&& push_items
> 0) {
3859 if (path
->slots
[0] < i
)
3861 if (path
->slots
[0] == i
) {
3862 int space
= btrfs_leaf_free_space(root
, right
);
3863 if (space
+ push_space
* 2 > free_space
)
3868 if (path
->slots
[0] == i
)
3869 push_space
+= data_size
;
3871 this_item_size
= btrfs_item_size(right
, item
);
3872 if (this_item_size
+ sizeof(*item
) + push_space
> free_space
)
3876 push_space
+= this_item_size
+ sizeof(*item
);
3879 if (push_items
== 0) {
3883 WARN_ON(!empty
&& push_items
== btrfs_header_nritems(right
));
3885 /* push data from right to left */
3886 copy_extent_buffer(left
, right
,
3887 btrfs_item_nr_offset(btrfs_header_nritems(left
)),
3888 btrfs_item_nr_offset(0),
3889 push_items
* sizeof(struct btrfs_item
));
3891 push_space
= BTRFS_LEAF_DATA_SIZE(root
) -
3892 btrfs_item_offset_nr(right
, push_items
- 1);
3894 copy_extent_buffer(left
, right
, btrfs_leaf_data(left
) +
3895 leaf_data_end(root
, left
) - push_space
,
3896 btrfs_leaf_data(right
) +
3897 btrfs_item_offset_nr(right
, push_items
- 1),
3899 old_left_nritems
= btrfs_header_nritems(left
);
3900 BUG_ON(old_left_nritems
<= 0);
3902 old_left_item_size
= btrfs_item_offset_nr(left
, old_left_nritems
- 1);
3903 for (i
= old_left_nritems
; i
< old_left_nritems
+ push_items
; i
++) {
3906 item
= btrfs_item_nr(i
);
3908 ioff
= btrfs_token_item_offset(left
, item
, &token
);
3909 btrfs_set_token_item_offset(left
, item
,
3910 ioff
- (BTRFS_LEAF_DATA_SIZE(root
) - old_left_item_size
),
3913 btrfs_set_header_nritems(left
, old_left_nritems
+ push_items
);
3915 /* fixup right node */
3916 if (push_items
> right_nritems
)
3917 WARN(1, KERN_CRIT
"push items %d nr %u\n", push_items
,
3920 if (push_items
< right_nritems
) {
3921 push_space
= btrfs_item_offset_nr(right
, push_items
- 1) -
3922 leaf_data_end(root
, right
);
3923 memmove_extent_buffer(right
, btrfs_leaf_data(right
) +
3924 BTRFS_LEAF_DATA_SIZE(root
) - push_space
,
3925 btrfs_leaf_data(right
) +
3926 leaf_data_end(root
, right
), push_space
);
3928 memmove_extent_buffer(right
, btrfs_item_nr_offset(0),
3929 btrfs_item_nr_offset(push_items
),
3930 (btrfs_header_nritems(right
) - push_items
) *
3931 sizeof(struct btrfs_item
));
3933 right_nritems
-= push_items
;
3934 btrfs_set_header_nritems(right
, right_nritems
);
3935 push_space
= BTRFS_LEAF_DATA_SIZE(root
);
3936 for (i
= 0; i
< right_nritems
; i
++) {
3937 item
= btrfs_item_nr(i
);
3939 push_space
= push_space
- btrfs_token_item_size(right
,
3941 btrfs_set_token_item_offset(right
, item
, push_space
, &token
);
3944 btrfs_mark_buffer_dirty(left
);
3946 btrfs_mark_buffer_dirty(right
);
3948 clean_tree_block(trans
, root
, right
);
3950 btrfs_item_key(right
, &disk_key
, 0);
3951 fixup_low_keys(root
, path
, &disk_key
, 1);
3953 /* then fixup the leaf pointer in the path */
3954 if (path
->slots
[0] < push_items
) {
3955 path
->slots
[0] += old_left_nritems
;
3956 btrfs_tree_unlock(path
->nodes
[0]);
3957 free_extent_buffer(path
->nodes
[0]);
3958 path
->nodes
[0] = left
;
3959 path
->slots
[1] -= 1;
3961 btrfs_tree_unlock(left
);
3962 free_extent_buffer(left
);
3963 path
->slots
[0] -= push_items
;
3965 BUG_ON(path
->slots
[0] < 0);
3968 btrfs_tree_unlock(left
);
3969 free_extent_buffer(left
);
3974 * push some data in the path leaf to the left, trying to free up at
3975 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3977 * max_slot can put a limit on how far into the leaf we'll push items. The
3978 * item at 'max_slot' won't be touched. Use (u32)-1 to make us push all the
3981 static int push_leaf_left(struct btrfs_trans_handle
*trans
, struct btrfs_root
3982 *root
, struct btrfs_path
*path
, int min_data_size
,
3983 int data_size
, int empty
, u32 max_slot
)
3985 struct extent_buffer
*right
= path
->nodes
[0];
3986 struct extent_buffer
*left
;
3992 slot
= path
->slots
[1];
3995 if (!path
->nodes
[1])
3998 right_nritems
= btrfs_header_nritems(right
);
3999 if (right_nritems
== 0)
4002 btrfs_assert_tree_locked(path
->nodes
[1]);
4004 left
= read_node_slot(root
, path
->nodes
[1], slot
- 1);
4008 btrfs_tree_lock(left
);
4009 btrfs_set_lock_blocking(left
);
4011 free_space
= btrfs_leaf_free_space(root
, left
);
4012 if (free_space
< data_size
) {
4017 /* cow and double check */
4018 ret
= btrfs_cow_block(trans
, root
, left
,
4019 path
->nodes
[1], slot
- 1, &left
);
4021 /* we hit -ENOSPC, but it isn't fatal here */
4027 free_space
= btrfs_leaf_free_space(root
, left
);
4028 if (free_space
< data_size
) {
4033 return __push_leaf_left(trans
, root
, path
, min_data_size
,
4034 empty
, left
, free_space
, right_nritems
,
4037 btrfs_tree_unlock(left
);
4038 free_extent_buffer(left
);
4043 * split the path's leaf in two, making sure there is at least data_size
4044 * available for the resulting leaf level of the path.
4046 static noinline
void copy_for_split(struct btrfs_trans_handle
*trans
,
4047 struct btrfs_root
*root
,
4048 struct btrfs_path
*path
,
4049 struct extent_buffer
*l
,
4050 struct extent_buffer
*right
,
4051 int slot
, int mid
, int nritems
)
4056 struct btrfs_disk_key disk_key
;
4057 struct btrfs_map_token token
;
4059 btrfs_init_map_token(&token
);
4061 nritems
= nritems
- mid
;
4062 btrfs_set_header_nritems(right
, nritems
);
4063 data_copy_size
= btrfs_item_end_nr(l
, mid
) - leaf_data_end(root
, l
);
4065 copy_extent_buffer(right
, l
, btrfs_item_nr_offset(0),
4066 btrfs_item_nr_offset(mid
),
4067 nritems
* sizeof(struct btrfs_item
));
4069 copy_extent_buffer(right
, l
,
4070 btrfs_leaf_data(right
) + BTRFS_LEAF_DATA_SIZE(root
) -
4071 data_copy_size
, btrfs_leaf_data(l
) +
4072 leaf_data_end(root
, l
), data_copy_size
);
4074 rt_data_off
= BTRFS_LEAF_DATA_SIZE(root
) -
4075 btrfs_item_end_nr(l
, mid
);
4077 for (i
= 0; i
< nritems
; i
++) {
4078 struct btrfs_item
*item
= btrfs_item_nr(i
);
4081 ioff
= btrfs_token_item_offset(right
, item
, &token
);
4082 btrfs_set_token_item_offset(right
, item
,
4083 ioff
+ rt_data_off
, &token
);
4086 btrfs_set_header_nritems(l
, mid
);
4087 btrfs_item_key(right
, &disk_key
, 0);
4088 insert_ptr(trans
, root
, path
, &disk_key
, right
->start
,
4089 path
->slots
[1] + 1, 1);
4091 btrfs_mark_buffer_dirty(right
);
4092 btrfs_mark_buffer_dirty(l
);
4093 BUG_ON(path
->slots
[0] != slot
);
4096 btrfs_tree_unlock(path
->nodes
[0]);
4097 free_extent_buffer(path
->nodes
[0]);
4098 path
->nodes
[0] = right
;
4099 path
->slots
[0] -= mid
;
4100 path
->slots
[1] += 1;
4102 btrfs_tree_unlock(right
);
4103 free_extent_buffer(right
);
4106 BUG_ON(path
->slots
[0] < 0);
4110 * double splits happen when we need to insert a big item in the middle
4111 * of a leaf. A double split can leave us with 3 mostly empty leaves:
4112 * leaf: [ slots 0 - N] [ our target ] [ N + 1 - total in leaf ]
4115 * We avoid this by trying to push the items on either side of our target
4116 * into the adjacent leaves. If all goes well we can avoid the double split
4119 static noinline
int push_for_double_split(struct btrfs_trans_handle
*trans
,
4120 struct btrfs_root
*root
,
4121 struct btrfs_path
*path
,
4128 int space_needed
= data_size
;
4130 slot
= path
->slots
[0];
4131 if (slot
< btrfs_header_nritems(path
->nodes
[0]))
4132 space_needed
-= btrfs_leaf_free_space(root
, path
->nodes
[0]);
4135 * try to push all the items after our slot into the
4138 ret
= push_leaf_right(trans
, root
, path
, 1, space_needed
, 0, slot
);
4145 nritems
= btrfs_header_nritems(path
->nodes
[0]);
4147 * our goal is to get our slot at the start or end of a leaf. If
4148 * we've done so we're done
4150 if (path
->slots
[0] == 0 || path
->slots
[0] == nritems
)
4153 if (btrfs_leaf_free_space(root
, path
->nodes
[0]) >= data_size
)
4156 /* try to push all the items before our slot into the next leaf */
4157 slot
= path
->slots
[0];
4158 ret
= push_leaf_left(trans
, root
, path
, 1, space_needed
, 0, slot
);
4171 * split the path's leaf in two, making sure there is at least data_size
4172 * available for the resulting leaf level of the path.
4174 * returns 0 if all went well and < 0 on failure.
4176 static noinline
int split_leaf(struct btrfs_trans_handle
*trans
,
4177 struct btrfs_root
*root
,
4178 struct btrfs_key
*ins_key
,
4179 struct btrfs_path
*path
, int data_size
,
4182 struct btrfs_disk_key disk_key
;
4183 struct extent_buffer
*l
;
4187 struct extent_buffer
*right
;
4191 int num_doubles
= 0;
4192 int tried_avoid_double
= 0;
4195 slot
= path
->slots
[0];
4196 if (extend
&& data_size
+ btrfs_item_size_nr(l
, slot
) +
4197 sizeof(struct btrfs_item
) > BTRFS_LEAF_DATA_SIZE(root
))
4200 /* first try to make some room by pushing left and right */
4201 if (data_size
&& path
->nodes
[1]) {
4202 int space_needed
= data_size
;
4204 if (slot
< btrfs_header_nritems(l
))
4205 space_needed
-= btrfs_leaf_free_space(root
, l
);
4207 wret
= push_leaf_right(trans
, root
, path
, space_needed
,
4208 space_needed
, 0, 0);
4212 wret
= push_leaf_left(trans
, root
, path
, space_needed
,
4213 space_needed
, 0, (u32
)-1);
4219 /* did the pushes work? */
4220 if (btrfs_leaf_free_space(root
, l
) >= data_size
)
4224 if (!path
->nodes
[1]) {
4225 ret
= insert_new_root(trans
, root
, path
, 1);
4232 slot
= path
->slots
[0];
4233 nritems
= btrfs_header_nritems(l
);
4234 mid
= (nritems
+ 1) / 2;
4238 leaf_space_used(l
, mid
, nritems
- mid
) + data_size
>
4239 BTRFS_LEAF_DATA_SIZE(root
)) {
4240 if (slot
>= nritems
) {
4244 if (mid
!= nritems
&&
4245 leaf_space_used(l
, mid
, nritems
- mid
) +
4246 data_size
> BTRFS_LEAF_DATA_SIZE(root
)) {
4247 if (data_size
&& !tried_avoid_double
)
4248 goto push_for_double
;
4254 if (leaf_space_used(l
, 0, mid
) + data_size
>
4255 BTRFS_LEAF_DATA_SIZE(root
)) {
4256 if (!extend
&& data_size
&& slot
== 0) {
4258 } else if ((extend
|| !data_size
) && slot
== 0) {
4262 if (mid
!= nritems
&&
4263 leaf_space_used(l
, mid
, nritems
- mid
) +
4264 data_size
> BTRFS_LEAF_DATA_SIZE(root
)) {
4265 if (data_size
&& !tried_avoid_double
)
4266 goto push_for_double
;
4274 btrfs_cpu_key_to_disk(&disk_key
, ins_key
);
4276 btrfs_item_key(l
, &disk_key
, mid
);
4278 right
= btrfs_alloc_free_block(trans
, root
, root
->nodesize
, 0,
4279 root
->root_key
.objectid
,
4280 &disk_key
, 0, l
->start
, 0);
4282 return PTR_ERR(right
);
4284 root_add_used(root
, root
->nodesize
);
4286 memset_extent_buffer(right
, 0, 0, sizeof(struct btrfs_header
));
4287 btrfs_set_header_bytenr(right
, right
->start
);
4288 btrfs_set_header_generation(right
, trans
->transid
);
4289 btrfs_set_header_backref_rev(right
, BTRFS_MIXED_BACKREF_REV
);
4290 btrfs_set_header_owner(right
, root
->root_key
.objectid
);
4291 btrfs_set_header_level(right
, 0);
4292 write_extent_buffer(right
, root
->fs_info
->fsid
,
4293 btrfs_header_fsid(), BTRFS_FSID_SIZE
);
4295 write_extent_buffer(right
, root
->fs_info
->chunk_tree_uuid
,
4296 btrfs_header_chunk_tree_uuid(right
),
4301 btrfs_set_header_nritems(right
, 0);
4302 insert_ptr(trans
, root
, path
, &disk_key
, right
->start
,
4303 path
->slots
[1] + 1, 1);
4304 btrfs_tree_unlock(path
->nodes
[0]);
4305 free_extent_buffer(path
->nodes
[0]);
4306 path
->nodes
[0] = right
;
4308 path
->slots
[1] += 1;
4310 btrfs_set_header_nritems(right
, 0);
4311 insert_ptr(trans
, root
, path
, &disk_key
, right
->start
,
4313 btrfs_tree_unlock(path
->nodes
[0]);
4314 free_extent_buffer(path
->nodes
[0]);
4315 path
->nodes
[0] = right
;
4317 if (path
->slots
[1] == 0)
4318 fixup_low_keys(root
, path
, &disk_key
, 1);
4320 btrfs_mark_buffer_dirty(right
);
4324 copy_for_split(trans
, root
, path
, l
, right
, slot
, mid
, nritems
);
4327 BUG_ON(num_doubles
!= 0);
4335 push_for_double_split(trans
, root
, path
, data_size
);
4336 tried_avoid_double
= 1;
4337 if (btrfs_leaf_free_space(root
, path
->nodes
[0]) >= data_size
)
4342 static noinline
int setup_leaf_for_split(struct btrfs_trans_handle
*trans
,
4343 struct btrfs_root
*root
,
4344 struct btrfs_path
*path
, int ins_len
)
4346 struct btrfs_key key
;
4347 struct extent_buffer
*leaf
;
4348 struct btrfs_file_extent_item
*fi
;
4353 leaf
= path
->nodes
[0];
4354 btrfs_item_key_to_cpu(leaf
, &key
, path
->slots
[0]);
4356 BUG_ON(key
.type
!= BTRFS_EXTENT_DATA_KEY
&&
4357 key
.type
!= BTRFS_EXTENT_CSUM_KEY
);
4359 if (btrfs_leaf_free_space(root
, leaf
) >= ins_len
)
4362 item_size
= btrfs_item_size_nr(leaf
, path
->slots
[0]);
4363 if (key
.type
== BTRFS_EXTENT_DATA_KEY
) {
4364 fi
= btrfs_item_ptr(leaf
, path
->slots
[0],
4365 struct btrfs_file_extent_item
);
4366 extent_len
= btrfs_file_extent_num_bytes(leaf
, fi
);
4368 btrfs_release_path(path
);
4370 path
->keep_locks
= 1;
4371 path
->search_for_split
= 1;
4372 ret
= btrfs_search_slot(trans
, root
, &key
, path
, 0, 1);
4373 path
->search_for_split
= 0;
4378 leaf
= path
->nodes
[0];
4379 /* if our item isn't there or got smaller, return now */
4380 if (ret
> 0 || item_size
!= btrfs_item_size_nr(leaf
, path
->slots
[0]))
4383 /* the leaf has changed, it now has room. return now */
4384 if (btrfs_leaf_free_space(root
, path
->nodes
[0]) >= ins_len
)
4387 if (key
.type
== BTRFS_EXTENT_DATA_KEY
) {
4388 fi
= btrfs_item_ptr(leaf
, path
->slots
[0],
4389 struct btrfs_file_extent_item
);
4390 if (extent_len
!= btrfs_file_extent_num_bytes(leaf
, fi
))
4394 btrfs_set_path_blocking(path
);
4395 ret
= split_leaf(trans
, root
, &key
, path
, ins_len
, 1);
4399 path
->keep_locks
= 0;
4400 btrfs_unlock_up_safe(path
, 1);
4403 path
->keep_locks
= 0;
4407 static noinline
int split_item(struct btrfs_trans_handle
*trans
,
4408 struct btrfs_root
*root
,
4409 struct btrfs_path
*path
,
4410 struct btrfs_key
*new_key
,
4411 unsigned long split_offset
)
4413 struct extent_buffer
*leaf
;
4414 struct btrfs_item
*item
;
4415 struct btrfs_item
*new_item
;
4421 struct btrfs_disk_key disk_key
;
4423 leaf
= path
->nodes
[0];
4424 BUG_ON(btrfs_leaf_free_space(root
, leaf
) < sizeof(struct btrfs_item
));
4426 btrfs_set_path_blocking(path
);
4428 item
= btrfs_item_nr(path
->slots
[0]);
4429 orig_offset
= btrfs_item_offset(leaf
, item
);
4430 item_size
= btrfs_item_size(leaf
, item
);
4432 buf
= kmalloc(item_size
, GFP_NOFS
);
4436 read_extent_buffer(leaf
, buf
, btrfs_item_ptr_offset(leaf
,
4437 path
->slots
[0]), item_size
);
4439 slot
= path
->slots
[0] + 1;
4440 nritems
= btrfs_header_nritems(leaf
);
4441 if (slot
!= nritems
) {
4442 /* shift the items */
4443 memmove_extent_buffer(leaf
, btrfs_item_nr_offset(slot
+ 1),
4444 btrfs_item_nr_offset(slot
),
4445 (nritems
- slot
) * sizeof(struct btrfs_item
));
4448 btrfs_cpu_key_to_disk(&disk_key
, new_key
);
4449 btrfs_set_item_key(leaf
, &disk_key
, slot
);
4451 new_item
= btrfs_item_nr(slot
);
4453 btrfs_set_item_offset(leaf
, new_item
, orig_offset
);
4454 btrfs_set_item_size(leaf
, new_item
, item_size
- split_offset
);
4456 btrfs_set_item_offset(leaf
, item
,
4457 orig_offset
+ item_size
- split_offset
);
4458 btrfs_set_item_size(leaf
, item
, split_offset
);
4460 btrfs_set_header_nritems(leaf
, nritems
+ 1);
4462 /* write the data for the start of the original item */
4463 write_extent_buffer(leaf
, buf
,
4464 btrfs_item_ptr_offset(leaf
, path
->slots
[0]),
4467 /* write the data for the new item */
4468 write_extent_buffer(leaf
, buf
+ split_offset
,
4469 btrfs_item_ptr_offset(leaf
, slot
),
4470 item_size
- split_offset
);
4471 btrfs_mark_buffer_dirty(leaf
);
4473 BUG_ON(btrfs_leaf_free_space(root
, leaf
) < 0);
4479 * This function splits a single item into two items,
4480 * giving 'new_key' to the new item and splitting the
4481 * old one at split_offset (from the start of the item).
4483 * The path may be released by this operation. After
4484 * the split, the path is pointing to the old item. The
4485 * new item is going to be in the same node as the old one.
4487 * Note, the item being split must be smaller enough to live alone on
4488 * a tree block with room for one extra struct btrfs_item
4490 * This allows us to split the item in place, keeping a lock on the
4491 * leaf the entire time.
4493 int btrfs_split_item(struct btrfs_trans_handle
*trans
,
4494 struct btrfs_root
*root
,
4495 struct btrfs_path
*path
,
4496 struct btrfs_key
*new_key
,
4497 unsigned long split_offset
)
4500 ret
= setup_leaf_for_split(trans
, root
, path
,
4501 sizeof(struct btrfs_item
));
4505 ret
= split_item(trans
, root
, path
, new_key
, split_offset
);
4510 * This function duplicate a item, giving 'new_key' to the new item.
4511 * It guarantees both items live in the same tree leaf and the new item
4512 * is contiguous with the original item.
4514 * This allows us to split file extent in place, keeping a lock on the
4515 * leaf the entire time.
4517 int btrfs_duplicate_item(struct btrfs_trans_handle
*trans
,
4518 struct btrfs_root
*root
,
4519 struct btrfs_path
*path
,
4520 struct btrfs_key
*new_key
)
4522 struct extent_buffer
*leaf
;
4526 leaf
= path
->nodes
[0];
4527 item_size
= btrfs_item_size_nr(leaf
, path
->slots
[0]);
4528 ret
= setup_leaf_for_split(trans
, root
, path
,
4529 item_size
+ sizeof(struct btrfs_item
));
4534 setup_items_for_insert(root
, path
, new_key
, &item_size
,
4535 item_size
, item_size
+
4536 sizeof(struct btrfs_item
), 1);
4537 leaf
= path
->nodes
[0];
4538 memcpy_extent_buffer(leaf
,
4539 btrfs_item_ptr_offset(leaf
, path
->slots
[0]),
4540 btrfs_item_ptr_offset(leaf
, path
->slots
[0] - 1),
4546 * make the item pointed to by the path smaller. new_size indicates
4547 * how small to make it, and from_end tells us if we just chop bytes
4548 * off the end of the item or if we shift the item to chop bytes off
4551 void btrfs_truncate_item(struct btrfs_root
*root
, struct btrfs_path
*path
,
4552 u32 new_size
, int from_end
)
4555 struct extent_buffer
*leaf
;
4556 struct btrfs_item
*item
;
4558 unsigned int data_end
;
4559 unsigned int old_data_start
;
4560 unsigned int old_size
;
4561 unsigned int size_diff
;
4563 struct btrfs_map_token token
;
4565 btrfs_init_map_token(&token
);
4567 leaf
= path
->nodes
[0];
4568 slot
= path
->slots
[0];
4570 old_size
= btrfs_item_size_nr(leaf
, slot
);
4571 if (old_size
== new_size
)
4574 nritems
= btrfs_header_nritems(leaf
);
4575 data_end
= leaf_data_end(root
, leaf
);
4577 old_data_start
= btrfs_item_offset_nr(leaf
, slot
);
4579 size_diff
= old_size
- new_size
;
4582 BUG_ON(slot
>= nritems
);
4585 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4587 /* first correct the data pointers */
4588 for (i
= slot
; i
< nritems
; i
++) {
4590 item
= btrfs_item_nr(i
);
4592 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4593 btrfs_set_token_item_offset(leaf
, item
,
4594 ioff
+ size_diff
, &token
);
4597 /* shift the data */
4599 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4600 data_end
+ size_diff
, btrfs_leaf_data(leaf
) +
4601 data_end
, old_data_start
+ new_size
- data_end
);
4603 struct btrfs_disk_key disk_key
;
4606 btrfs_item_key(leaf
, &disk_key
, slot
);
4608 if (btrfs_disk_key_type(&disk_key
) == BTRFS_EXTENT_DATA_KEY
) {
4610 struct btrfs_file_extent_item
*fi
;
4612 fi
= btrfs_item_ptr(leaf
, slot
,
4613 struct btrfs_file_extent_item
);
4614 fi
= (struct btrfs_file_extent_item
*)(
4615 (unsigned long)fi
- size_diff
);
4617 if (btrfs_file_extent_type(leaf
, fi
) ==
4618 BTRFS_FILE_EXTENT_INLINE
) {
4619 ptr
= btrfs_item_ptr_offset(leaf
, slot
);
4620 memmove_extent_buffer(leaf
, ptr
,
4622 offsetof(struct btrfs_file_extent_item
,
4627 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4628 data_end
+ size_diff
, btrfs_leaf_data(leaf
) +
4629 data_end
, old_data_start
- data_end
);
4631 offset
= btrfs_disk_key_offset(&disk_key
);
4632 btrfs_set_disk_key_offset(&disk_key
, offset
+ size_diff
);
4633 btrfs_set_item_key(leaf
, &disk_key
, slot
);
4635 fixup_low_keys(root
, path
, &disk_key
, 1);
4638 item
= btrfs_item_nr(slot
);
4639 btrfs_set_item_size(leaf
, item
, new_size
);
4640 btrfs_mark_buffer_dirty(leaf
);
4642 if (btrfs_leaf_free_space(root
, leaf
) < 0) {
4643 btrfs_print_leaf(root
, leaf
);
4649 * make the item pointed to by the path bigger, data_size is the added size.
4651 void btrfs_extend_item(struct btrfs_root
*root
, struct btrfs_path
*path
,
4655 struct extent_buffer
*leaf
;
4656 struct btrfs_item
*item
;
4658 unsigned int data_end
;
4659 unsigned int old_data
;
4660 unsigned int old_size
;
4662 struct btrfs_map_token token
;
4664 btrfs_init_map_token(&token
);
4666 leaf
= path
->nodes
[0];
4668 nritems
= btrfs_header_nritems(leaf
);
4669 data_end
= leaf_data_end(root
, leaf
);
4671 if (btrfs_leaf_free_space(root
, leaf
) < data_size
) {
4672 btrfs_print_leaf(root
, leaf
);
4675 slot
= path
->slots
[0];
4676 old_data
= btrfs_item_end_nr(leaf
, slot
);
4679 if (slot
>= nritems
) {
4680 btrfs_print_leaf(root
, leaf
);
4681 btrfs_crit(root
->fs_info
, "slot %d too large, nritems %d",
4687 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4689 /* first correct the data pointers */
4690 for (i
= slot
; i
< nritems
; i
++) {
4692 item
= btrfs_item_nr(i
);
4694 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4695 btrfs_set_token_item_offset(leaf
, item
,
4696 ioff
- data_size
, &token
);
4699 /* shift the data */
4700 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4701 data_end
- data_size
, btrfs_leaf_data(leaf
) +
4702 data_end
, old_data
- data_end
);
4704 data_end
= old_data
;
4705 old_size
= btrfs_item_size_nr(leaf
, slot
);
4706 item
= btrfs_item_nr(slot
);
4707 btrfs_set_item_size(leaf
, item
, old_size
+ data_size
);
4708 btrfs_mark_buffer_dirty(leaf
);
4710 if (btrfs_leaf_free_space(root
, leaf
) < 0) {
4711 btrfs_print_leaf(root
, leaf
);
4717 * this is a helper for btrfs_insert_empty_items, the main goal here is
4718 * to save stack depth by doing the bulk of the work in a function
4719 * that doesn't call btrfs_search_slot
4721 void setup_items_for_insert(struct btrfs_root
*root
, struct btrfs_path
*path
,
4722 struct btrfs_key
*cpu_key
, u32
*data_size
,
4723 u32 total_data
, u32 total_size
, int nr
)
4725 struct btrfs_item
*item
;
4728 unsigned int data_end
;
4729 struct btrfs_disk_key disk_key
;
4730 struct extent_buffer
*leaf
;
4732 struct btrfs_map_token token
;
4734 if (path
->slots
[0] == 0) {
4735 btrfs_cpu_key_to_disk(&disk_key
, cpu_key
);
4736 fixup_low_keys(root
, path
, &disk_key
, 1);
4738 btrfs_unlock_up_safe(path
, 1);
4740 btrfs_init_map_token(&token
);
4742 leaf
= path
->nodes
[0];
4743 slot
= path
->slots
[0];
4745 nritems
= btrfs_header_nritems(leaf
);
4746 data_end
= leaf_data_end(root
, leaf
);
4748 if (btrfs_leaf_free_space(root
, leaf
) < total_size
) {
4749 btrfs_print_leaf(root
, leaf
);
4750 btrfs_crit(root
->fs_info
, "not enough freespace need %u have %d",
4751 total_size
, btrfs_leaf_free_space(root
, leaf
));
4755 if (slot
!= nritems
) {
4756 unsigned int old_data
= btrfs_item_end_nr(leaf
, slot
);
4758 if (old_data
< data_end
) {
4759 btrfs_print_leaf(root
, leaf
);
4760 btrfs_crit(root
->fs_info
, "slot %d old_data %d data_end %d",
4761 slot
, old_data
, data_end
);
4765 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4767 /* first correct the data pointers */
4768 for (i
= slot
; i
< nritems
; i
++) {
4771 item
= btrfs_item_nr( i
);
4772 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4773 btrfs_set_token_item_offset(leaf
, item
,
4774 ioff
- total_data
, &token
);
4776 /* shift the items */
4777 memmove_extent_buffer(leaf
, btrfs_item_nr_offset(slot
+ nr
),
4778 btrfs_item_nr_offset(slot
),
4779 (nritems
- slot
) * sizeof(struct btrfs_item
));
4781 /* shift the data */
4782 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4783 data_end
- total_data
, btrfs_leaf_data(leaf
) +
4784 data_end
, old_data
- data_end
);
4785 data_end
= old_data
;
4788 /* setup the item for the new data */
4789 for (i
= 0; i
< nr
; i
++) {
4790 btrfs_cpu_key_to_disk(&disk_key
, cpu_key
+ i
);
4791 btrfs_set_item_key(leaf
, &disk_key
, slot
+ i
);
4792 item
= btrfs_item_nr(slot
+ i
);
4793 btrfs_set_token_item_offset(leaf
, item
,
4794 data_end
- data_size
[i
], &token
);
4795 data_end
-= data_size
[i
];
4796 btrfs_set_token_item_size(leaf
, item
, data_size
[i
], &token
);
4799 btrfs_set_header_nritems(leaf
, nritems
+ nr
);
4800 btrfs_mark_buffer_dirty(leaf
);
4802 if (btrfs_leaf_free_space(root
, leaf
) < 0) {
4803 btrfs_print_leaf(root
, leaf
);
4809 * Given a key and some data, insert items into the tree.
4810 * This does all the path init required, making room in the tree if needed.
4812 int btrfs_insert_empty_items(struct btrfs_trans_handle
*trans
,
4813 struct btrfs_root
*root
,
4814 struct btrfs_path
*path
,
4815 struct btrfs_key
*cpu_key
, u32
*data_size
,
4824 for (i
= 0; i
< nr
; i
++)
4825 total_data
+= data_size
[i
];
4827 total_size
= total_data
+ (nr
* sizeof(struct btrfs_item
));
4828 ret
= btrfs_search_slot(trans
, root
, cpu_key
, path
, total_size
, 1);
4834 slot
= path
->slots
[0];
4837 setup_items_for_insert(root
, path
, cpu_key
, data_size
,
4838 total_data
, total_size
, nr
);
4843 * Given a key and some data, insert an item into the tree.
4844 * This does all the path init required, making room in the tree if needed.
4846 int btrfs_insert_item(struct btrfs_trans_handle
*trans
, struct btrfs_root
4847 *root
, struct btrfs_key
*cpu_key
, void *data
, u32
4851 struct btrfs_path
*path
;
4852 struct extent_buffer
*leaf
;
4855 path
= btrfs_alloc_path();
4858 ret
= btrfs_insert_empty_item(trans
, root
, path
, cpu_key
, data_size
);
4860 leaf
= path
->nodes
[0];
4861 ptr
= btrfs_item_ptr_offset(leaf
, path
->slots
[0]);
4862 write_extent_buffer(leaf
, data
, ptr
, data_size
);
4863 btrfs_mark_buffer_dirty(leaf
);
4865 btrfs_free_path(path
);
4870 * delete the pointer from a given node.
4872 * the tree should have been previously balanced so the deletion does not
4875 static void del_ptr(struct btrfs_root
*root
, struct btrfs_path
*path
,
4876 int level
, int slot
)
4878 struct extent_buffer
*parent
= path
->nodes
[level
];
4882 nritems
= btrfs_header_nritems(parent
);
4883 if (slot
!= nritems
- 1) {
4885 tree_mod_log_eb_move(root
->fs_info
, parent
, slot
,
4886 slot
+ 1, nritems
- slot
- 1);
4887 memmove_extent_buffer(parent
,
4888 btrfs_node_key_ptr_offset(slot
),
4889 btrfs_node_key_ptr_offset(slot
+ 1),
4890 sizeof(struct btrfs_key_ptr
) *
4891 (nritems
- slot
- 1));
4893 ret
= tree_mod_log_insert_key(root
->fs_info
, parent
, slot
,
4894 MOD_LOG_KEY_REMOVE
, GFP_NOFS
);
4899 btrfs_set_header_nritems(parent
, nritems
);
4900 if (nritems
== 0 && parent
== root
->node
) {
4901 BUG_ON(btrfs_header_level(root
->node
) != 1);
4902 /* just turn the root into a leaf and break */
4903 btrfs_set_header_level(root
->node
, 0);
4904 } else if (slot
== 0) {
4905 struct btrfs_disk_key disk_key
;
4907 btrfs_node_key(parent
, &disk_key
, 0);
4908 fixup_low_keys(root
, path
, &disk_key
, level
+ 1);
4910 btrfs_mark_buffer_dirty(parent
);
4914 * a helper function to delete the leaf pointed to by path->slots[1] and
4917 * This deletes the pointer in path->nodes[1] and frees the leaf
4918 * block extent. zero is returned if it all worked out, < 0 otherwise.
4920 * The path must have already been setup for deleting the leaf, including
4921 * all the proper balancing. path->nodes[1] must be locked.
4923 static noinline
void btrfs_del_leaf(struct btrfs_trans_handle
*trans
,
4924 struct btrfs_root
*root
,
4925 struct btrfs_path
*path
,
4926 struct extent_buffer
*leaf
)
4928 WARN_ON(btrfs_header_generation(leaf
) != trans
->transid
);
4929 del_ptr(root
, path
, 1, path
->slots
[1]);
4932 * btrfs_free_extent is expensive, we want to make sure we
4933 * aren't holding any locks when we call it
4935 btrfs_unlock_up_safe(path
, 0);
4937 root_sub_used(root
, leaf
->len
);
4939 extent_buffer_get(leaf
);
4940 btrfs_free_tree_block(trans
, root
, leaf
, 0, 1);
4941 free_extent_buffer_stale(leaf
);
4944 * delete the item at the leaf level in path. If that empties
4945 * the leaf, remove it from the tree
4947 int btrfs_del_items(struct btrfs_trans_handle
*trans
, struct btrfs_root
*root
,
4948 struct btrfs_path
*path
, int slot
, int nr
)
4950 struct extent_buffer
*leaf
;
4951 struct btrfs_item
*item
;
4958 struct btrfs_map_token token
;
4960 btrfs_init_map_token(&token
);
4962 leaf
= path
->nodes
[0];
4963 last_off
= btrfs_item_offset_nr(leaf
, slot
+ nr
- 1);
4965 for (i
= 0; i
< nr
; i
++)
4966 dsize
+= btrfs_item_size_nr(leaf
, slot
+ i
);
4968 nritems
= btrfs_header_nritems(leaf
);
4970 if (slot
+ nr
!= nritems
) {
4971 int data_end
= leaf_data_end(root
, leaf
);
4973 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4975 btrfs_leaf_data(leaf
) + data_end
,
4976 last_off
- data_end
);
4978 for (i
= slot
+ nr
; i
< nritems
; i
++) {
4981 item
= btrfs_item_nr(i
);
4982 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4983 btrfs_set_token_item_offset(leaf
, item
,
4984 ioff
+ dsize
, &token
);
4987 memmove_extent_buffer(leaf
, btrfs_item_nr_offset(slot
),
4988 btrfs_item_nr_offset(slot
+ nr
),
4989 sizeof(struct btrfs_item
) *
4990 (nritems
- slot
- nr
));
4992 btrfs_set_header_nritems(leaf
, nritems
- nr
);
4995 /* delete the leaf if we've emptied it */
4997 if (leaf
== root
->node
) {
4998 btrfs_set_header_level(leaf
, 0);
5000 btrfs_set_path_blocking(path
);
5001 clean_tree_block(trans
, root
, leaf
);
5002 btrfs_del_leaf(trans
, root
, path
, leaf
);
5005 int used
= leaf_space_used(leaf
, 0, nritems
);
5007 struct btrfs_disk_key disk_key
;
5009 btrfs_item_key(leaf
, &disk_key
, 0);
5010 fixup_low_keys(root
, path
, &disk_key
, 1);
5013 /* delete the leaf if it is mostly empty */
5014 if (used
< BTRFS_LEAF_DATA_SIZE(root
) / 3) {
5015 /* push_leaf_left fixes the path.
5016 * make sure the path still points to our leaf
5017 * for possible call to del_ptr below
5019 slot
= path
->slots
[1];
5020 extent_buffer_get(leaf
);
5022 btrfs_set_path_blocking(path
);
5023 wret
= push_leaf_left(trans
, root
, path
, 1, 1,
5025 if (wret
< 0 && wret
!= -ENOSPC
)
5028 if (path
->nodes
[0] == leaf
&&
5029 btrfs_header_nritems(leaf
)) {
5030 wret
= push_leaf_right(trans
, root
, path
, 1,
5032 if (wret
< 0 && wret
!= -ENOSPC
)
5036 if (btrfs_header_nritems(leaf
) == 0) {
5037 path
->slots
[1] = slot
;
5038 btrfs_del_leaf(trans
, root
, path
, leaf
);
5039 free_extent_buffer(leaf
);
5042 /* if we're still in the path, make sure
5043 * we're dirty. Otherwise, one of the
5044 * push_leaf functions must have already
5045 * dirtied this buffer
5047 if (path
->nodes
[0] == leaf
)
5048 btrfs_mark_buffer_dirty(leaf
);
5049 free_extent_buffer(leaf
);
5052 btrfs_mark_buffer_dirty(leaf
);
5059 * search the tree again to find a leaf with lesser keys
5060 * returns 0 if it found something or 1 if there are no lesser leaves.
5061 * returns < 0 on io errors.
5063 * This may release the path, and so you may lose any locks held at the
5066 int btrfs_prev_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
)
5068 struct btrfs_key key
;
5069 struct btrfs_disk_key found_key
;
5072 btrfs_item_key_to_cpu(path
->nodes
[0], &key
, 0);
5074 if (key
.offset
> 0) {
5076 } else if (key
.type
> 0) {
5078 key
.offset
= (u64
)-1;
5079 } else if (key
.objectid
> 0) {
5082 key
.offset
= (u64
)-1;
5087 btrfs_release_path(path
);
5088 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
5091 btrfs_item_key(path
->nodes
[0], &found_key
, 0);
5092 ret
= comp_keys(&found_key
, &key
);
5094 * We might have had an item with the previous key in the tree right
5095 * before we released our path. And after we released our path, that
5096 * item might have been pushed to the first slot (0) of the leaf we
5097 * were holding due to a tree balance. Alternatively, an item with the
5098 * previous key can exist as the only element of a leaf (big fat item).
5099 * Therefore account for these 2 cases, so that our callers (like
5100 * btrfs_previous_item) don't miss an existing item with a key matching
5101 * the previous key we computed above.
5109 * A helper function to walk down the tree starting at min_key, and looking
5110 * for nodes or leaves that are have a minimum transaction id.
5111 * This is used by the btree defrag code, and tree logging
5113 * This does not cow, but it does stuff the starting key it finds back
5114 * into min_key, so you can call btrfs_search_slot with cow=1 on the
5115 * key and get a writable path.
5117 * This does lock as it descends, and path->keep_locks should be set
5118 * to 1 by the caller.
5120 * This honors path->lowest_level to prevent descent past a given level
5123 * min_trans indicates the oldest transaction that you are interested
5124 * in walking through. Any nodes or leaves older than min_trans are
5125 * skipped over (without reading them).
5127 * returns zero if something useful was found, < 0 on error and 1 if there
5128 * was nothing in the tree that matched the search criteria.
5130 int btrfs_search_forward(struct btrfs_root
*root
, struct btrfs_key
*min_key
,
5131 struct btrfs_path
*path
,
5134 struct extent_buffer
*cur
;
5135 struct btrfs_key found_key
;
5141 int keep_locks
= path
->keep_locks
;
5143 path
->keep_locks
= 1;
5145 cur
= btrfs_read_lock_root_node(root
);
5146 level
= btrfs_header_level(cur
);
5147 WARN_ON(path
->nodes
[level
]);
5148 path
->nodes
[level
] = cur
;
5149 path
->locks
[level
] = BTRFS_READ_LOCK
;
5151 if (btrfs_header_generation(cur
) < min_trans
) {
5156 nritems
= btrfs_header_nritems(cur
);
5157 level
= btrfs_header_level(cur
);
5158 sret
= bin_search(cur
, min_key
, level
, &slot
);
5160 /* at the lowest level, we're done, setup the path and exit */
5161 if (level
== path
->lowest_level
) {
5162 if (slot
>= nritems
)
5165 path
->slots
[level
] = slot
;
5166 btrfs_item_key_to_cpu(cur
, &found_key
, slot
);
5169 if (sret
&& slot
> 0)
5172 * check this node pointer against the min_trans parameters.
5173 * If it is too old, old, skip to the next one.
5175 while (slot
< nritems
) {
5178 gen
= btrfs_node_ptr_generation(cur
, slot
);
5179 if (gen
< min_trans
) {
5187 * we didn't find a candidate key in this node, walk forward
5188 * and find another one
5190 if (slot
>= nritems
) {
5191 path
->slots
[level
] = slot
;
5192 btrfs_set_path_blocking(path
);
5193 sret
= btrfs_find_next_key(root
, path
, min_key
, level
,
5196 btrfs_release_path(path
);
5202 /* save our key for returning back */
5203 btrfs_node_key_to_cpu(cur
, &found_key
, slot
);
5204 path
->slots
[level
] = slot
;
5205 if (level
== path
->lowest_level
) {
5209 btrfs_set_path_blocking(path
);
5210 cur
= read_node_slot(root
, cur
, slot
);
5211 BUG_ON(!cur
); /* -ENOMEM */
5213 btrfs_tree_read_lock(cur
);
5215 path
->locks
[level
- 1] = BTRFS_READ_LOCK
;
5216 path
->nodes
[level
- 1] = cur
;
5217 unlock_up(path
, level
, 1, 0, NULL
);
5218 btrfs_clear_path_blocking(path
, NULL
, 0);
5221 path
->keep_locks
= keep_locks
;
5223 btrfs_unlock_up_safe(path
, path
->lowest_level
+ 1);
5224 btrfs_set_path_blocking(path
);
5225 memcpy(min_key
, &found_key
, sizeof(found_key
));
5230 static void tree_move_down(struct btrfs_root
*root
,
5231 struct btrfs_path
*path
,
5232 int *level
, int root_level
)
5234 BUG_ON(*level
== 0);
5235 path
->nodes
[*level
- 1] = read_node_slot(root
, path
->nodes
[*level
],
5236 path
->slots
[*level
]);
5237 path
->slots
[*level
- 1] = 0;
5241 static int tree_move_next_or_upnext(struct btrfs_root
*root
,
5242 struct btrfs_path
*path
,
5243 int *level
, int root_level
)
5247 nritems
= btrfs_header_nritems(path
->nodes
[*level
]);
5249 path
->slots
[*level
]++;
5251 while (path
->slots
[*level
] >= nritems
) {
5252 if (*level
== root_level
)
5256 path
->slots
[*level
] = 0;
5257 free_extent_buffer(path
->nodes
[*level
]);
5258 path
->nodes
[*level
] = NULL
;
5260 path
->slots
[*level
]++;
5262 nritems
= btrfs_header_nritems(path
->nodes
[*level
]);
5269 * Returns 1 if it had to move up and next. 0 is returned if it moved only next
5272 static int tree_advance(struct btrfs_root
*root
,
5273 struct btrfs_path
*path
,
5274 int *level
, int root_level
,
5276 struct btrfs_key
*key
)
5280 if (*level
== 0 || !allow_down
) {
5281 ret
= tree_move_next_or_upnext(root
, path
, level
, root_level
);
5283 tree_move_down(root
, path
, level
, root_level
);
5288 btrfs_item_key_to_cpu(path
->nodes
[*level
], key
,
5289 path
->slots
[*level
]);
5291 btrfs_node_key_to_cpu(path
->nodes
[*level
], key
,
5292 path
->slots
[*level
]);
5297 static int tree_compare_item(struct btrfs_root
*left_root
,
5298 struct btrfs_path
*left_path
,
5299 struct btrfs_path
*right_path
,
5304 unsigned long off1
, off2
;
5306 len1
= btrfs_item_size_nr(left_path
->nodes
[0], left_path
->slots
[0]);
5307 len2
= btrfs_item_size_nr(right_path
->nodes
[0], right_path
->slots
[0]);
5311 off1
= btrfs_item_ptr_offset(left_path
->nodes
[0], left_path
->slots
[0]);
5312 off2
= btrfs_item_ptr_offset(right_path
->nodes
[0],
5313 right_path
->slots
[0]);
5315 read_extent_buffer(left_path
->nodes
[0], tmp_buf
, off1
, len1
);
5317 cmp
= memcmp_extent_buffer(right_path
->nodes
[0], tmp_buf
, off2
, len1
);
5324 #define ADVANCE_ONLY_NEXT -1
5327 * This function compares two trees and calls the provided callback for
5328 * every changed/new/deleted item it finds.
5329 * If shared tree blocks are encountered, whole subtrees are skipped, making
5330 * the compare pretty fast on snapshotted subvolumes.
5332 * This currently works on commit roots only. As commit roots are read only,
5333 * we don't do any locking. The commit roots are protected with transactions.
5334 * Transactions are ended and rejoined when a commit is tried in between.
5336 * This function checks for modifications done to the trees while comparing.
5337 * If it detects a change, it aborts immediately.
5339 int btrfs_compare_trees(struct btrfs_root
*left_root
,
5340 struct btrfs_root
*right_root
,
5341 btrfs_changed_cb_t changed_cb
, void *ctx
)
5345 struct btrfs_path
*left_path
= NULL
;
5346 struct btrfs_path
*right_path
= NULL
;
5347 struct btrfs_key left_key
;
5348 struct btrfs_key right_key
;
5349 char *tmp_buf
= NULL
;
5350 int left_root_level
;
5351 int right_root_level
;
5354 int left_end_reached
;
5355 int right_end_reached
;
5363 left_path
= btrfs_alloc_path();
5368 right_path
= btrfs_alloc_path();
5374 tmp_buf
= kmalloc(left_root
->nodesize
, GFP_NOFS
);
5380 left_path
->search_commit_root
= 1;
5381 left_path
->skip_locking
= 1;
5382 right_path
->search_commit_root
= 1;
5383 right_path
->skip_locking
= 1;
5386 * Strategy: Go to the first items of both trees. Then do
5388 * If both trees are at level 0
5389 * Compare keys of current items
5390 * If left < right treat left item as new, advance left tree
5392 * If left > right treat right item as deleted, advance right tree
5394 * If left == right do deep compare of items, treat as changed if
5395 * needed, advance both trees and repeat
5396 * If both trees are at the same level but not at level 0
5397 * Compare keys of current nodes/leafs
5398 * If left < right advance left tree and repeat
5399 * If left > right advance right tree and repeat
5400 * If left == right compare blockptrs of the next nodes/leafs
5401 * If they match advance both trees but stay at the same level
5403 * If they don't match advance both trees while allowing to go
5405 * If tree levels are different
5406 * Advance the tree that needs it and repeat
5408 * Advancing a tree means:
5409 * If we are at level 0, try to go to the next slot. If that's not
5410 * possible, go one level up and repeat. Stop when we found a level
5411 * where we could go to the next slot. We may at this point be on a
5414 * If we are not at level 0 and not on shared tree blocks, go one
5417 * If we are not at level 0 and on shared tree blocks, go one slot to
5418 * the right if possible or go up and right.
5421 down_read(&left_root
->fs_info
->commit_root_sem
);
5422 left_level
= btrfs_header_level(left_root
->commit_root
);
5423 left_root_level
= left_level
;
5424 left_path
->nodes
[left_level
] = left_root
->commit_root
;
5425 extent_buffer_get(left_path
->nodes
[left_level
]);
5427 right_level
= btrfs_header_level(right_root
->commit_root
);
5428 right_root_level
= right_level
;
5429 right_path
->nodes
[right_level
] = right_root
->commit_root
;
5430 extent_buffer_get(right_path
->nodes
[right_level
]);
5431 up_read(&left_root
->fs_info
->commit_root_sem
);
5433 if (left_level
== 0)
5434 btrfs_item_key_to_cpu(left_path
->nodes
[left_level
],
5435 &left_key
, left_path
->slots
[left_level
]);
5437 btrfs_node_key_to_cpu(left_path
->nodes
[left_level
],
5438 &left_key
, left_path
->slots
[left_level
]);
5439 if (right_level
== 0)
5440 btrfs_item_key_to_cpu(right_path
->nodes
[right_level
],
5441 &right_key
, right_path
->slots
[right_level
]);
5443 btrfs_node_key_to_cpu(right_path
->nodes
[right_level
],
5444 &right_key
, right_path
->slots
[right_level
]);
5446 left_end_reached
= right_end_reached
= 0;
5447 advance_left
= advance_right
= 0;
5450 if (advance_left
&& !left_end_reached
) {
5451 ret
= tree_advance(left_root
, left_path
, &left_level
,
5453 advance_left
!= ADVANCE_ONLY_NEXT
,
5456 left_end_reached
= ADVANCE
;
5459 if (advance_right
&& !right_end_reached
) {
5460 ret
= tree_advance(right_root
, right_path
, &right_level
,
5462 advance_right
!= ADVANCE_ONLY_NEXT
,
5465 right_end_reached
= ADVANCE
;
5469 if (left_end_reached
&& right_end_reached
) {
5472 } else if (left_end_reached
) {
5473 if (right_level
== 0) {
5474 ret
= changed_cb(left_root
, right_root
,
5475 left_path
, right_path
,
5477 BTRFS_COMPARE_TREE_DELETED
,
5482 advance_right
= ADVANCE
;
5484 } else if (right_end_reached
) {
5485 if (left_level
== 0) {
5486 ret
= changed_cb(left_root
, right_root
,
5487 left_path
, right_path
,
5489 BTRFS_COMPARE_TREE_NEW
,
5494 advance_left
= ADVANCE
;
5498 if (left_level
== 0 && right_level
== 0) {
5499 cmp
= btrfs_comp_cpu_keys(&left_key
, &right_key
);
5501 ret
= changed_cb(left_root
, right_root
,
5502 left_path
, right_path
,
5504 BTRFS_COMPARE_TREE_NEW
,
5508 advance_left
= ADVANCE
;
5509 } else if (cmp
> 0) {
5510 ret
= changed_cb(left_root
, right_root
,
5511 left_path
, right_path
,
5513 BTRFS_COMPARE_TREE_DELETED
,
5517 advance_right
= ADVANCE
;
5519 enum btrfs_compare_tree_result cmp
;
5521 WARN_ON(!extent_buffer_uptodate(left_path
->nodes
[0]));
5522 ret
= tree_compare_item(left_root
, left_path
,
5523 right_path
, tmp_buf
);
5525 cmp
= BTRFS_COMPARE_TREE_CHANGED
;
5527 cmp
= BTRFS_COMPARE_TREE_SAME
;
5528 ret
= changed_cb(left_root
, right_root
,
5529 left_path
, right_path
,
5530 &left_key
, cmp
, ctx
);
5533 advance_left
= ADVANCE
;
5534 advance_right
= ADVANCE
;
5536 } else if (left_level
== right_level
) {
5537 cmp
= btrfs_comp_cpu_keys(&left_key
, &right_key
);
5539 advance_left
= ADVANCE
;
5540 } else if (cmp
> 0) {
5541 advance_right
= ADVANCE
;
5543 left_blockptr
= btrfs_node_blockptr(
5544 left_path
->nodes
[left_level
],
5545 left_path
->slots
[left_level
]);
5546 right_blockptr
= btrfs_node_blockptr(
5547 right_path
->nodes
[right_level
],
5548 right_path
->slots
[right_level
]);
5549 left_gen
= btrfs_node_ptr_generation(
5550 left_path
->nodes
[left_level
],
5551 left_path
->slots
[left_level
]);
5552 right_gen
= btrfs_node_ptr_generation(
5553 right_path
->nodes
[right_level
],
5554 right_path
->slots
[right_level
]);
5555 if (left_blockptr
== right_blockptr
&&
5556 left_gen
== right_gen
) {
5558 * As we're on a shared block, don't
5559 * allow to go deeper.
5561 advance_left
= ADVANCE_ONLY_NEXT
;
5562 advance_right
= ADVANCE_ONLY_NEXT
;
5564 advance_left
= ADVANCE
;
5565 advance_right
= ADVANCE
;
5568 } else if (left_level
< right_level
) {
5569 advance_right
= ADVANCE
;
5571 advance_left
= ADVANCE
;
5576 btrfs_free_path(left_path
);
5577 btrfs_free_path(right_path
);
5583 * this is similar to btrfs_next_leaf, but does not try to preserve
5584 * and fixup the path. It looks for and returns the next key in the
5585 * tree based on the current path and the min_trans parameters.
5587 * 0 is returned if another key is found, < 0 if there are any errors
5588 * and 1 is returned if there are no higher keys in the tree
5590 * path->keep_locks should be set to 1 on the search made before
5591 * calling this function.
5593 int btrfs_find_next_key(struct btrfs_root
*root
, struct btrfs_path
*path
,
5594 struct btrfs_key
*key
, int level
, u64 min_trans
)
5597 struct extent_buffer
*c
;
5599 WARN_ON(!path
->keep_locks
);
5600 while (level
< BTRFS_MAX_LEVEL
) {
5601 if (!path
->nodes
[level
])
5604 slot
= path
->slots
[level
] + 1;
5605 c
= path
->nodes
[level
];
5607 if (slot
>= btrfs_header_nritems(c
)) {
5610 struct btrfs_key cur_key
;
5611 if (level
+ 1 >= BTRFS_MAX_LEVEL
||
5612 !path
->nodes
[level
+ 1])
5615 if (path
->locks
[level
+ 1]) {
5620 slot
= btrfs_header_nritems(c
) - 1;
5622 btrfs_item_key_to_cpu(c
, &cur_key
, slot
);
5624 btrfs_node_key_to_cpu(c
, &cur_key
, slot
);
5626 orig_lowest
= path
->lowest_level
;
5627 btrfs_release_path(path
);
5628 path
->lowest_level
= level
;
5629 ret
= btrfs_search_slot(NULL
, root
, &cur_key
, path
,
5631 path
->lowest_level
= orig_lowest
;
5635 c
= path
->nodes
[level
];
5636 slot
= path
->slots
[level
];
5643 btrfs_item_key_to_cpu(c
, key
, slot
);
5645 u64 gen
= btrfs_node_ptr_generation(c
, slot
);
5647 if (gen
< min_trans
) {
5651 btrfs_node_key_to_cpu(c
, key
, slot
);
5659 * search the tree again to find a leaf with greater keys
5660 * returns 0 if it found something or 1 if there are no greater leaves.
5661 * returns < 0 on io errors.
5663 int btrfs_next_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
)
5665 return btrfs_next_old_leaf(root
, path
, 0);
5668 int btrfs_next_old_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
,
5673 struct extent_buffer
*c
;
5674 struct extent_buffer
*next
;
5675 struct btrfs_key key
;
5678 int old_spinning
= path
->leave_spinning
;
5679 int next_rw_lock
= 0;
5681 nritems
= btrfs_header_nritems(path
->nodes
[0]);
5685 btrfs_item_key_to_cpu(path
->nodes
[0], &key
, nritems
- 1);
5690 btrfs_release_path(path
);
5692 path
->keep_locks
= 1;
5693 path
->leave_spinning
= 1;
5696 ret
= btrfs_search_old_slot(root
, &key
, path
, time_seq
);
5698 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
5699 path
->keep_locks
= 0;
5704 nritems
= btrfs_header_nritems(path
->nodes
[0]);
5706 * by releasing the path above we dropped all our locks. A balance
5707 * could have added more items next to the key that used to be
5708 * at the very end of the block. So, check again here and
5709 * advance the path if there are now more items available.
5711 if (nritems
> 0 && path
->slots
[0] < nritems
- 1) {
5718 * So the above check misses one case:
5719 * - after releasing the path above, someone has removed the item that
5720 * used to be at the very end of the block, and balance between leafs
5721 * gets another one with bigger key.offset to replace it.
5723 * This one should be returned as well, or we can get leaf corruption
5724 * later(esp. in __btrfs_drop_extents()).
5726 * And a bit more explanation about this check,
5727 * with ret > 0, the key isn't found, the path points to the slot
5728 * where it should be inserted, so the path->slots[0] item must be the
5731 if (nritems
> 0 && ret
> 0 && path
->slots
[0] == nritems
- 1) {
5736 while (level
< BTRFS_MAX_LEVEL
) {
5737 if (!path
->nodes
[level
]) {
5742 slot
= path
->slots
[level
] + 1;
5743 c
= path
->nodes
[level
];
5744 if (slot
>= btrfs_header_nritems(c
)) {
5746 if (level
== BTRFS_MAX_LEVEL
) {
5754 btrfs_tree_unlock_rw(next
, next_rw_lock
);
5755 free_extent_buffer(next
);
5759 next_rw_lock
= path
->locks
[level
];
5760 ret
= read_block_for_search(NULL
, root
, path
, &next
, level
,
5766 btrfs_release_path(path
);
5770 if (!path
->skip_locking
) {
5771 ret
= btrfs_try_tree_read_lock(next
);
5772 if (!ret
&& time_seq
) {
5774 * If we don't get the lock, we may be racing
5775 * with push_leaf_left, holding that lock while
5776 * itself waiting for the leaf we've currently
5777 * locked. To solve this situation, we give up
5778 * on our lock and cycle.
5780 free_extent_buffer(next
);
5781 btrfs_release_path(path
);
5786 btrfs_set_path_blocking(path
);
5787 btrfs_tree_read_lock(next
);
5788 btrfs_clear_path_blocking(path
, next
,
5791 next_rw_lock
= BTRFS_READ_LOCK
;
5795 path
->slots
[level
] = slot
;
5798 c
= path
->nodes
[level
];
5799 if (path
->locks
[level
])
5800 btrfs_tree_unlock_rw(c
, path
->locks
[level
]);
5802 free_extent_buffer(c
);
5803 path
->nodes
[level
] = next
;
5804 path
->slots
[level
] = 0;
5805 if (!path
->skip_locking
)
5806 path
->locks
[level
] = next_rw_lock
;
5810 ret
= read_block_for_search(NULL
, root
, path
, &next
, level
,
5816 btrfs_release_path(path
);
5820 if (!path
->skip_locking
) {
5821 ret
= btrfs_try_tree_read_lock(next
);
5823 btrfs_set_path_blocking(path
);
5824 btrfs_tree_read_lock(next
);
5825 btrfs_clear_path_blocking(path
, next
,
5828 next_rw_lock
= BTRFS_READ_LOCK
;
5833 unlock_up(path
, 0, 1, 0, NULL
);
5834 path
->leave_spinning
= old_spinning
;
5836 btrfs_set_path_blocking(path
);
5842 * this uses btrfs_prev_leaf to walk backwards in the tree, and keeps
5843 * searching until it gets past min_objectid or finds an item of 'type'
5845 * returns 0 if something is found, 1 if nothing was found and < 0 on error
5847 int btrfs_previous_item(struct btrfs_root
*root
,
5848 struct btrfs_path
*path
, u64 min_objectid
,
5851 struct btrfs_key found_key
;
5852 struct extent_buffer
*leaf
;
5857 if (path
->slots
[0] == 0) {
5858 btrfs_set_path_blocking(path
);
5859 ret
= btrfs_prev_leaf(root
, path
);
5865 leaf
= path
->nodes
[0];
5866 nritems
= btrfs_header_nritems(leaf
);
5869 if (path
->slots
[0] == nritems
)
5872 btrfs_item_key_to_cpu(leaf
, &found_key
, path
->slots
[0]);
5873 if (found_key
.objectid
< min_objectid
)
5875 if (found_key
.type
== type
)
5877 if (found_key
.objectid
== min_objectid
&&
5878 found_key
.type
< type
)
5885 * search in extent tree to find a previous Metadata/Data extent item with
5888 * returns 0 if something is found, 1 if nothing was found and < 0 on error
5890 int btrfs_previous_extent_item(struct btrfs_root
*root
,
5891 struct btrfs_path
*path
, u64 min_objectid
)
5893 struct btrfs_key found_key
;
5894 struct extent_buffer
*leaf
;
5899 if (path
->slots
[0] == 0) {
5900 btrfs_set_path_blocking(path
);
5901 ret
= btrfs_prev_leaf(root
, path
);
5907 leaf
= path
->nodes
[0];
5908 nritems
= btrfs_header_nritems(leaf
);
5911 if (path
->slots
[0] == nritems
)
5914 btrfs_item_key_to_cpu(leaf
, &found_key
, path
->slots
[0]);
5915 if (found_key
.objectid
< min_objectid
)
5917 if (found_key
.type
== BTRFS_EXTENT_ITEM_KEY
||
5918 found_key
.type
== BTRFS_METADATA_ITEM_KEY
)
5920 if (found_key
.objectid
== min_objectid
&&
5921 found_key
.type
< BTRFS_EXTENT_ITEM_KEY
)