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>
23 #include "transaction.h"
24 #include "print-tree.h"
27 static int split_node(struct btrfs_trans_handle
*trans
, struct btrfs_root
28 *root
, struct btrfs_path
*path
, int level
);
29 static int split_leaf(struct btrfs_trans_handle
*trans
, struct btrfs_root
30 *root
, struct btrfs_key
*ins_key
,
31 struct btrfs_path
*path
, int data_size
, int extend
);
32 static int push_node_left(struct btrfs_trans_handle
*trans
,
33 struct btrfs_root
*root
, struct extent_buffer
*dst
,
34 struct extent_buffer
*src
, int empty
);
35 static int balance_node_right(struct btrfs_trans_handle
*trans
,
36 struct btrfs_root
*root
,
37 struct extent_buffer
*dst_buf
,
38 struct extent_buffer
*src_buf
);
39 static void del_ptr(struct btrfs_trans_handle
*trans
, struct btrfs_root
*root
,
40 struct btrfs_path
*path
, int level
, int slot
);
42 struct btrfs_path
*btrfs_alloc_path(void)
44 struct btrfs_path
*path
;
45 path
= kmem_cache_zalloc(btrfs_path_cachep
, GFP_NOFS
);
50 * set all locked nodes in the path to blocking locks. This should
51 * be done before scheduling
53 noinline
void btrfs_set_path_blocking(struct btrfs_path
*p
)
56 for (i
= 0; i
< BTRFS_MAX_LEVEL
; i
++) {
57 if (!p
->nodes
[i
] || !p
->locks
[i
])
59 btrfs_set_lock_blocking_rw(p
->nodes
[i
], p
->locks
[i
]);
60 if (p
->locks
[i
] == BTRFS_READ_LOCK
)
61 p
->locks
[i
] = BTRFS_READ_LOCK_BLOCKING
;
62 else if (p
->locks
[i
] == BTRFS_WRITE_LOCK
)
63 p
->locks
[i
] = BTRFS_WRITE_LOCK_BLOCKING
;
68 * reset all the locked nodes in the patch to spinning locks.
70 * held is used to keep lockdep happy, when lockdep is enabled
71 * we set held to a blocking lock before we go around and
72 * retake all the spinlocks in the path. You can safely use NULL
75 noinline
void btrfs_clear_path_blocking(struct btrfs_path
*p
,
76 struct extent_buffer
*held
, int held_rw
)
80 #ifdef CONFIG_DEBUG_LOCK_ALLOC
81 /* lockdep really cares that we take all of these spinlocks
82 * in the right order. If any of the locks in the path are not
83 * currently blocking, it is going to complain. So, make really
84 * really sure by forcing the path to blocking before we clear
88 btrfs_set_lock_blocking_rw(held
, held_rw
);
89 if (held_rw
== BTRFS_WRITE_LOCK
)
90 held_rw
= BTRFS_WRITE_LOCK_BLOCKING
;
91 else if (held_rw
== BTRFS_READ_LOCK
)
92 held_rw
= BTRFS_READ_LOCK_BLOCKING
;
94 btrfs_set_path_blocking(p
);
97 for (i
= BTRFS_MAX_LEVEL
- 1; i
>= 0; i
--) {
98 if (p
->nodes
[i
] && p
->locks
[i
]) {
99 btrfs_clear_lock_blocking_rw(p
->nodes
[i
], p
->locks
[i
]);
100 if (p
->locks
[i
] == BTRFS_WRITE_LOCK_BLOCKING
)
101 p
->locks
[i
] = BTRFS_WRITE_LOCK
;
102 else if (p
->locks
[i
] == BTRFS_READ_LOCK_BLOCKING
)
103 p
->locks
[i
] = BTRFS_READ_LOCK
;
107 #ifdef CONFIG_DEBUG_LOCK_ALLOC
109 btrfs_clear_lock_blocking_rw(held
, held_rw
);
113 /* this also releases the path */
114 void btrfs_free_path(struct btrfs_path
*p
)
118 btrfs_release_path(p
);
119 kmem_cache_free(btrfs_path_cachep
, p
);
123 * path release drops references on the extent buffers in the path
124 * and it drops any locks held by this path
126 * It is safe to call this on paths that no locks or extent buffers held.
128 noinline
void btrfs_release_path(struct btrfs_path
*p
)
132 for (i
= 0; i
< BTRFS_MAX_LEVEL
; i
++) {
137 btrfs_tree_unlock_rw(p
->nodes
[i
], p
->locks
[i
]);
140 free_extent_buffer(p
->nodes
[i
]);
146 * safely gets a reference on the root node of a tree. A lock
147 * is not taken, so a concurrent writer may put a different node
148 * at the root of the tree. See btrfs_lock_root_node for the
151 * The extent buffer returned by this has a reference taken, so
152 * it won't disappear. It may stop being the root of the tree
153 * at any time because there are no locks held.
155 struct extent_buffer
*btrfs_root_node(struct btrfs_root
*root
)
157 struct extent_buffer
*eb
;
160 eb
= rcu_dereference(root
->node
);
161 extent_buffer_get(eb
);
166 /* loop around taking references on and locking the root node of the
167 * tree until you end up with a lock on the root. A locked buffer
168 * is returned, with a reference held.
170 struct extent_buffer
*btrfs_lock_root_node(struct btrfs_root
*root
)
172 struct extent_buffer
*eb
;
175 eb
= btrfs_root_node(root
);
177 if (eb
== root
->node
)
179 btrfs_tree_unlock(eb
);
180 free_extent_buffer(eb
);
185 /* loop around taking references on and locking the root node of the
186 * tree until you end up with a lock on the root. A locked buffer
187 * is returned, with a reference held.
189 struct extent_buffer
*btrfs_read_lock_root_node(struct btrfs_root
*root
)
191 struct extent_buffer
*eb
;
194 eb
= btrfs_root_node(root
);
195 btrfs_tree_read_lock(eb
);
196 if (eb
== root
->node
)
198 btrfs_tree_read_unlock(eb
);
199 free_extent_buffer(eb
);
204 /* cowonly root (everything not a reference counted cow subvolume), just get
205 * put onto a simple dirty list. transaction.c walks this to make sure they
206 * get properly updated on disk.
208 static void add_root_to_dirty_list(struct btrfs_root
*root
)
210 if (root
->track_dirty
&& list_empty(&root
->dirty_list
)) {
211 list_add(&root
->dirty_list
,
212 &root
->fs_info
->dirty_cowonly_roots
);
217 * used by snapshot creation to make a copy of a root for a tree with
218 * a given objectid. The buffer with the new root node is returned in
219 * cow_ret, and this func returns zero on success or a negative error code.
221 int btrfs_copy_root(struct btrfs_trans_handle
*trans
,
222 struct btrfs_root
*root
,
223 struct extent_buffer
*buf
,
224 struct extent_buffer
**cow_ret
, u64 new_root_objectid
)
226 struct extent_buffer
*cow
;
229 struct btrfs_disk_key disk_key
;
231 WARN_ON(root
->ref_cows
&& trans
->transid
!=
232 root
->fs_info
->running_transaction
->transid
);
233 WARN_ON(root
->ref_cows
&& trans
->transid
!= root
->last_trans
);
235 level
= btrfs_header_level(buf
);
237 btrfs_item_key(buf
, &disk_key
, 0);
239 btrfs_node_key(buf
, &disk_key
, 0);
241 cow
= btrfs_alloc_free_block(trans
, root
, buf
->len
, 0,
242 new_root_objectid
, &disk_key
, level
,
247 copy_extent_buffer(cow
, buf
, 0, 0, cow
->len
);
248 btrfs_set_header_bytenr(cow
, cow
->start
);
249 btrfs_set_header_generation(cow
, trans
->transid
);
250 btrfs_set_header_backref_rev(cow
, BTRFS_MIXED_BACKREF_REV
);
251 btrfs_clear_header_flag(cow
, BTRFS_HEADER_FLAG_WRITTEN
|
252 BTRFS_HEADER_FLAG_RELOC
);
253 if (new_root_objectid
== BTRFS_TREE_RELOC_OBJECTID
)
254 btrfs_set_header_flag(cow
, BTRFS_HEADER_FLAG_RELOC
);
256 btrfs_set_header_owner(cow
, new_root_objectid
);
258 write_extent_buffer(cow
, root
->fs_info
->fsid
,
259 (unsigned long)btrfs_header_fsid(cow
),
262 WARN_ON(btrfs_header_generation(buf
) > trans
->transid
);
263 if (new_root_objectid
== BTRFS_TREE_RELOC_OBJECTID
)
264 ret
= btrfs_inc_ref(trans
, root
, cow
, 1, 1);
266 ret
= btrfs_inc_ref(trans
, root
, cow
, 0, 1);
271 btrfs_mark_buffer_dirty(cow
);
277 * check if the tree block can be shared by multiple trees
279 int btrfs_block_can_be_shared(struct btrfs_root
*root
,
280 struct extent_buffer
*buf
)
283 * Tree blocks not in refernece counted trees and tree roots
284 * are never shared. If a block was allocated after the last
285 * snapshot and the block was not allocated by tree relocation,
286 * we know the block is not shared.
288 if (root
->ref_cows
&&
289 buf
!= root
->node
&& buf
!= root
->commit_root
&&
290 (btrfs_header_generation(buf
) <=
291 btrfs_root_last_snapshot(&root
->root_item
) ||
292 btrfs_header_flag(buf
, BTRFS_HEADER_FLAG_RELOC
)))
294 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
295 if (root
->ref_cows
&&
296 btrfs_header_backref_rev(buf
) < BTRFS_MIXED_BACKREF_REV
)
302 static noinline
int update_ref_for_cow(struct btrfs_trans_handle
*trans
,
303 struct btrfs_root
*root
,
304 struct extent_buffer
*buf
,
305 struct extent_buffer
*cow
,
315 * Backrefs update rules:
317 * Always use full backrefs for extent pointers in tree block
318 * allocated by tree relocation.
320 * If a shared tree block is no longer referenced by its owner
321 * tree (btrfs_header_owner(buf) == root->root_key.objectid),
322 * use full backrefs for extent pointers in tree block.
324 * If a tree block is been relocating
325 * (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID),
326 * use full backrefs for extent pointers in tree block.
327 * The reason for this is some operations (such as drop tree)
328 * are only allowed for blocks use full backrefs.
331 if (btrfs_block_can_be_shared(root
, buf
)) {
332 ret
= btrfs_lookup_extent_info(trans
, root
, buf
->start
,
333 buf
->len
, &refs
, &flags
);
338 btrfs_std_error(root
->fs_info
, ret
);
343 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
||
344 btrfs_header_backref_rev(buf
) < BTRFS_MIXED_BACKREF_REV
)
345 flags
= BTRFS_BLOCK_FLAG_FULL_BACKREF
;
350 owner
= btrfs_header_owner(buf
);
351 BUG_ON(owner
== BTRFS_TREE_RELOC_OBJECTID
&&
352 !(flags
& BTRFS_BLOCK_FLAG_FULL_BACKREF
));
355 if ((owner
== root
->root_key
.objectid
||
356 root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
) &&
357 !(flags
& BTRFS_BLOCK_FLAG_FULL_BACKREF
)) {
358 ret
= btrfs_inc_ref(trans
, root
, buf
, 1, 1);
359 BUG_ON(ret
); /* -ENOMEM */
361 if (root
->root_key
.objectid
==
362 BTRFS_TREE_RELOC_OBJECTID
) {
363 ret
= btrfs_dec_ref(trans
, root
, buf
, 0, 1);
364 BUG_ON(ret
); /* -ENOMEM */
365 ret
= btrfs_inc_ref(trans
, root
, cow
, 1, 1);
366 BUG_ON(ret
); /* -ENOMEM */
368 new_flags
|= BTRFS_BLOCK_FLAG_FULL_BACKREF
;
371 if (root
->root_key
.objectid
==
372 BTRFS_TREE_RELOC_OBJECTID
)
373 ret
= btrfs_inc_ref(trans
, root
, cow
, 1, 1);
375 ret
= btrfs_inc_ref(trans
, root
, cow
, 0, 1);
376 BUG_ON(ret
); /* -ENOMEM */
378 if (new_flags
!= 0) {
379 ret
= btrfs_set_disk_extent_flags(trans
, root
,
387 if (flags
& BTRFS_BLOCK_FLAG_FULL_BACKREF
) {
388 if (root
->root_key
.objectid
==
389 BTRFS_TREE_RELOC_OBJECTID
)
390 ret
= btrfs_inc_ref(trans
, root
, cow
, 1, 1);
392 ret
= btrfs_inc_ref(trans
, root
, cow
, 0, 1);
393 BUG_ON(ret
); /* -ENOMEM */
394 ret
= btrfs_dec_ref(trans
, root
, buf
, 1, 1);
395 BUG_ON(ret
); /* -ENOMEM */
397 clean_tree_block(trans
, root
, buf
);
404 * does the dirty work in cow of a single block. The parent block (if
405 * supplied) is updated to point to the new cow copy. The new buffer is marked
406 * dirty and returned locked. If you modify the block it needs to be marked
409 * search_start -- an allocation hint for the new block
411 * empty_size -- a hint that you plan on doing more cow. This is the size in
412 * bytes the allocator should try to find free next to the block it returns.
413 * This is just a hint and may be ignored by the allocator.
415 static noinline
int __btrfs_cow_block(struct btrfs_trans_handle
*trans
,
416 struct btrfs_root
*root
,
417 struct extent_buffer
*buf
,
418 struct extent_buffer
*parent
, int parent_slot
,
419 struct extent_buffer
**cow_ret
,
420 u64 search_start
, u64 empty_size
)
422 struct btrfs_disk_key disk_key
;
423 struct extent_buffer
*cow
;
432 btrfs_assert_tree_locked(buf
);
434 WARN_ON(root
->ref_cows
&& trans
->transid
!=
435 root
->fs_info
->running_transaction
->transid
);
436 WARN_ON(root
->ref_cows
&& trans
->transid
!= root
->last_trans
);
438 level
= btrfs_header_level(buf
);
441 btrfs_item_key(buf
, &disk_key
, 0);
443 btrfs_node_key(buf
, &disk_key
, 0);
445 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
) {
447 parent_start
= parent
->start
;
453 cow
= btrfs_alloc_free_block(trans
, root
, buf
->len
, parent_start
,
454 root
->root_key
.objectid
, &disk_key
,
455 level
, search_start
, empty_size
, 1);
459 /* cow is set to blocking by btrfs_init_new_buffer */
461 copy_extent_buffer(cow
, buf
, 0, 0, cow
->len
);
462 btrfs_set_header_bytenr(cow
, cow
->start
);
463 btrfs_set_header_generation(cow
, trans
->transid
);
464 btrfs_set_header_backref_rev(cow
, BTRFS_MIXED_BACKREF_REV
);
465 btrfs_clear_header_flag(cow
, BTRFS_HEADER_FLAG_WRITTEN
|
466 BTRFS_HEADER_FLAG_RELOC
);
467 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
)
468 btrfs_set_header_flag(cow
, BTRFS_HEADER_FLAG_RELOC
);
470 btrfs_set_header_owner(cow
, root
->root_key
.objectid
);
472 write_extent_buffer(cow
, root
->fs_info
->fsid
,
473 (unsigned long)btrfs_header_fsid(cow
),
476 ret
= update_ref_for_cow(trans
, root
, buf
, cow
, &last_ref
);
478 btrfs_abort_transaction(trans
, root
, ret
);
483 btrfs_reloc_cow_block(trans
, root
, buf
, cow
);
485 if (buf
== root
->node
) {
486 WARN_ON(parent
&& parent
!= buf
);
487 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
||
488 btrfs_header_backref_rev(buf
) < BTRFS_MIXED_BACKREF_REV
)
489 parent_start
= buf
->start
;
493 extent_buffer_get(cow
);
494 rcu_assign_pointer(root
->node
, cow
);
496 btrfs_free_tree_block(trans
, root
, buf
, parent_start
,
498 free_extent_buffer(buf
);
499 add_root_to_dirty_list(root
);
501 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
)
502 parent_start
= parent
->start
;
506 WARN_ON(trans
->transid
!= btrfs_header_generation(parent
));
507 btrfs_set_node_blockptr(parent
, parent_slot
,
509 btrfs_set_node_ptr_generation(parent
, parent_slot
,
511 btrfs_mark_buffer_dirty(parent
);
512 btrfs_free_tree_block(trans
, root
, buf
, parent_start
,
516 btrfs_tree_unlock(buf
);
517 free_extent_buffer(buf
);
518 btrfs_mark_buffer_dirty(cow
);
523 static inline int should_cow_block(struct btrfs_trans_handle
*trans
,
524 struct btrfs_root
*root
,
525 struct extent_buffer
*buf
)
527 /* ensure we can see the force_cow */
531 * We do not need to cow a block if
532 * 1) this block is not created or changed in this transaction;
533 * 2) this block does not belong to TREE_RELOC tree;
534 * 3) the root is not forced COW.
536 * What is forced COW:
537 * when we create snapshot during commiting the transaction,
538 * after we've finished coping src root, we must COW the shared
539 * block to ensure the metadata consistency.
541 if (btrfs_header_generation(buf
) == trans
->transid
&&
542 !btrfs_header_flag(buf
, BTRFS_HEADER_FLAG_WRITTEN
) &&
543 !(root
->root_key
.objectid
!= BTRFS_TREE_RELOC_OBJECTID
&&
544 btrfs_header_flag(buf
, BTRFS_HEADER_FLAG_RELOC
)) &&
551 * cows a single block, see __btrfs_cow_block for the real work.
552 * This version of it has extra checks so that a block isn't cow'd more than
553 * once per transaction, as long as it hasn't been written yet
555 noinline
int btrfs_cow_block(struct btrfs_trans_handle
*trans
,
556 struct btrfs_root
*root
, struct extent_buffer
*buf
,
557 struct extent_buffer
*parent
, int parent_slot
,
558 struct extent_buffer
**cow_ret
)
563 if (trans
->transaction
!= root
->fs_info
->running_transaction
) {
564 printk(KERN_CRIT
"trans %llu running %llu\n",
565 (unsigned long long)trans
->transid
,
567 root
->fs_info
->running_transaction
->transid
);
570 if (trans
->transid
!= root
->fs_info
->generation
) {
571 printk(KERN_CRIT
"trans %llu running %llu\n",
572 (unsigned long long)trans
->transid
,
573 (unsigned long long)root
->fs_info
->generation
);
577 if (!should_cow_block(trans
, root
, buf
)) {
582 search_start
= buf
->start
& ~((u64
)(1024 * 1024 * 1024) - 1);
585 btrfs_set_lock_blocking(parent
);
586 btrfs_set_lock_blocking(buf
);
588 ret
= __btrfs_cow_block(trans
, root
, buf
, parent
,
589 parent_slot
, cow_ret
, search_start
, 0);
591 trace_btrfs_cow_block(root
, buf
, *cow_ret
);
597 * helper function for defrag to decide if two blocks pointed to by a
598 * node are actually close by
600 static int close_blocks(u64 blocknr
, u64 other
, u32 blocksize
)
602 if (blocknr
< other
&& other
- (blocknr
+ blocksize
) < 32768)
604 if (blocknr
> other
&& blocknr
- (other
+ blocksize
) < 32768)
610 * compare two keys in a memcmp fashion
612 static int comp_keys(struct btrfs_disk_key
*disk
, struct btrfs_key
*k2
)
616 btrfs_disk_key_to_cpu(&k1
, disk
);
618 return btrfs_comp_cpu_keys(&k1
, k2
);
622 * same as comp_keys only with two btrfs_key's
624 int btrfs_comp_cpu_keys(struct btrfs_key
*k1
, struct btrfs_key
*k2
)
626 if (k1
->objectid
> k2
->objectid
)
628 if (k1
->objectid
< k2
->objectid
)
630 if (k1
->type
> k2
->type
)
632 if (k1
->type
< k2
->type
)
634 if (k1
->offset
> k2
->offset
)
636 if (k1
->offset
< k2
->offset
)
642 * this is used by the defrag code to go through all the
643 * leaves pointed to by a node and reallocate them so that
644 * disk order is close to key order
646 int btrfs_realloc_node(struct btrfs_trans_handle
*trans
,
647 struct btrfs_root
*root
, struct extent_buffer
*parent
,
648 int start_slot
, int cache_only
, u64
*last_ret
,
649 struct btrfs_key
*progress
)
651 struct extent_buffer
*cur
;
654 u64 search_start
= *last_ret
;
664 int progress_passed
= 0;
665 struct btrfs_disk_key disk_key
;
667 parent_level
= btrfs_header_level(parent
);
668 if (cache_only
&& parent_level
!= 1)
671 if (trans
->transaction
!= root
->fs_info
->running_transaction
)
673 if (trans
->transid
!= root
->fs_info
->generation
)
676 parent_nritems
= btrfs_header_nritems(parent
);
677 blocksize
= btrfs_level_size(root
, parent_level
- 1);
678 end_slot
= parent_nritems
;
680 if (parent_nritems
== 1)
683 btrfs_set_lock_blocking(parent
);
685 for (i
= start_slot
; i
< end_slot
; i
++) {
688 btrfs_node_key(parent
, &disk_key
, i
);
689 if (!progress_passed
&& comp_keys(&disk_key
, progress
) < 0)
693 blocknr
= btrfs_node_blockptr(parent
, i
);
694 gen
= btrfs_node_ptr_generation(parent
, i
);
696 last_block
= blocknr
;
699 other
= btrfs_node_blockptr(parent
, i
- 1);
700 close
= close_blocks(blocknr
, other
, blocksize
);
702 if (!close
&& i
< end_slot
- 2) {
703 other
= btrfs_node_blockptr(parent
, i
+ 1);
704 close
= close_blocks(blocknr
, other
, blocksize
);
707 last_block
= blocknr
;
711 cur
= btrfs_find_tree_block(root
, blocknr
, blocksize
);
713 uptodate
= btrfs_buffer_uptodate(cur
, gen
);
716 if (!cur
|| !uptodate
) {
718 free_extent_buffer(cur
);
722 cur
= read_tree_block(root
, blocknr
,
726 } else if (!uptodate
) {
727 btrfs_read_buffer(cur
, gen
);
730 if (search_start
== 0)
731 search_start
= last_block
;
733 btrfs_tree_lock(cur
);
734 btrfs_set_lock_blocking(cur
);
735 err
= __btrfs_cow_block(trans
, root
, cur
, parent
, i
,
738 (end_slot
- i
) * blocksize
));
740 btrfs_tree_unlock(cur
);
741 free_extent_buffer(cur
);
744 search_start
= cur
->start
;
745 last_block
= cur
->start
;
746 *last_ret
= search_start
;
747 btrfs_tree_unlock(cur
);
748 free_extent_buffer(cur
);
754 * The leaf data grows from end-to-front in the node.
755 * this returns the address of the start of the last item,
756 * which is the stop of the leaf data stack
758 static inline unsigned int leaf_data_end(struct btrfs_root
*root
,
759 struct extent_buffer
*leaf
)
761 u32 nr
= btrfs_header_nritems(leaf
);
763 return BTRFS_LEAF_DATA_SIZE(root
);
764 return btrfs_item_offset_nr(leaf
, nr
- 1);
769 * search for key in the extent_buffer. The items start at offset p,
770 * and they are item_size apart. There are 'max' items in p.
772 * the slot in the array is returned via slot, and it points to
773 * the place where you would insert key if it is not found in
776 * slot may point to max if the key is bigger than all of the keys
778 static noinline
int generic_bin_search(struct extent_buffer
*eb
,
780 int item_size
, struct btrfs_key
*key
,
787 struct btrfs_disk_key
*tmp
= NULL
;
788 struct btrfs_disk_key unaligned
;
789 unsigned long offset
;
791 unsigned long map_start
= 0;
792 unsigned long map_len
= 0;
796 mid
= (low
+ high
) / 2;
797 offset
= p
+ mid
* item_size
;
799 if (!kaddr
|| offset
< map_start
||
800 (offset
+ sizeof(struct btrfs_disk_key
)) >
801 map_start
+ map_len
) {
803 err
= map_private_extent_buffer(eb
, offset
,
804 sizeof(struct btrfs_disk_key
),
805 &kaddr
, &map_start
, &map_len
);
808 tmp
= (struct btrfs_disk_key
*)(kaddr
+ offset
-
811 read_extent_buffer(eb
, &unaligned
,
812 offset
, sizeof(unaligned
));
817 tmp
= (struct btrfs_disk_key
*)(kaddr
+ offset
-
820 ret
= comp_keys(tmp
, key
);
836 * simple bin_search frontend that does the right thing for
839 static int bin_search(struct extent_buffer
*eb
, struct btrfs_key
*key
,
840 int level
, int *slot
)
843 return generic_bin_search(eb
,
844 offsetof(struct btrfs_leaf
, items
),
845 sizeof(struct btrfs_item
),
846 key
, btrfs_header_nritems(eb
),
849 return generic_bin_search(eb
,
850 offsetof(struct btrfs_node
, ptrs
),
851 sizeof(struct btrfs_key_ptr
),
852 key
, btrfs_header_nritems(eb
),
858 int btrfs_bin_search(struct extent_buffer
*eb
, struct btrfs_key
*key
,
859 int level
, int *slot
)
861 return bin_search(eb
, key
, level
, slot
);
864 static void root_add_used(struct btrfs_root
*root
, u32 size
)
866 spin_lock(&root
->accounting_lock
);
867 btrfs_set_root_used(&root
->root_item
,
868 btrfs_root_used(&root
->root_item
) + size
);
869 spin_unlock(&root
->accounting_lock
);
872 static void root_sub_used(struct btrfs_root
*root
, u32 size
)
874 spin_lock(&root
->accounting_lock
);
875 btrfs_set_root_used(&root
->root_item
,
876 btrfs_root_used(&root
->root_item
) - size
);
877 spin_unlock(&root
->accounting_lock
);
880 /* given a node and slot number, this reads the blocks it points to. The
881 * extent buffer is returned with a reference taken (but unlocked).
882 * NULL is returned on error.
884 static noinline
struct extent_buffer
*read_node_slot(struct btrfs_root
*root
,
885 struct extent_buffer
*parent
, int slot
)
887 int level
= btrfs_header_level(parent
);
890 if (slot
>= btrfs_header_nritems(parent
))
895 return read_tree_block(root
, btrfs_node_blockptr(parent
, slot
),
896 btrfs_level_size(root
, level
- 1),
897 btrfs_node_ptr_generation(parent
, slot
));
901 * node level balancing, used to make sure nodes are in proper order for
902 * item deletion. We balance from the top down, so we have to make sure
903 * that a deletion won't leave an node completely empty later on.
905 static noinline
int balance_level(struct btrfs_trans_handle
*trans
,
906 struct btrfs_root
*root
,
907 struct btrfs_path
*path
, int level
)
909 struct extent_buffer
*right
= NULL
;
910 struct extent_buffer
*mid
;
911 struct extent_buffer
*left
= NULL
;
912 struct extent_buffer
*parent
= NULL
;
916 int orig_slot
= path
->slots
[level
];
922 mid
= path
->nodes
[level
];
924 WARN_ON(path
->locks
[level
] != BTRFS_WRITE_LOCK
&&
925 path
->locks
[level
] != BTRFS_WRITE_LOCK_BLOCKING
);
926 WARN_ON(btrfs_header_generation(mid
) != trans
->transid
);
928 orig_ptr
= btrfs_node_blockptr(mid
, orig_slot
);
930 if (level
< BTRFS_MAX_LEVEL
- 1) {
931 parent
= path
->nodes
[level
+ 1];
932 pslot
= path
->slots
[level
+ 1];
936 * deal with the case where there is only one pointer in the root
937 * by promoting the node below to a root
940 struct extent_buffer
*child
;
942 if (btrfs_header_nritems(mid
) != 1)
945 /* promote the child to a root */
946 child
= read_node_slot(root
, mid
, 0);
949 btrfs_std_error(root
->fs_info
, ret
);
953 btrfs_tree_lock(child
);
954 btrfs_set_lock_blocking(child
);
955 ret
= btrfs_cow_block(trans
, root
, child
, mid
, 0, &child
);
957 btrfs_tree_unlock(child
);
958 free_extent_buffer(child
);
962 rcu_assign_pointer(root
->node
, child
);
964 add_root_to_dirty_list(root
);
965 btrfs_tree_unlock(child
);
967 path
->locks
[level
] = 0;
968 path
->nodes
[level
] = NULL
;
969 clean_tree_block(trans
, root
, mid
);
970 btrfs_tree_unlock(mid
);
971 /* once for the path */
972 free_extent_buffer(mid
);
974 root_sub_used(root
, mid
->len
);
975 btrfs_free_tree_block(trans
, root
, mid
, 0, 1, 0);
976 /* once for the root ptr */
977 free_extent_buffer(mid
);
980 if (btrfs_header_nritems(mid
) >
981 BTRFS_NODEPTRS_PER_BLOCK(root
) / 4)
984 btrfs_header_nritems(mid
);
986 left
= read_node_slot(root
, parent
, pslot
- 1);
988 btrfs_tree_lock(left
);
989 btrfs_set_lock_blocking(left
);
990 wret
= btrfs_cow_block(trans
, root
, left
,
991 parent
, pslot
- 1, &left
);
997 right
= read_node_slot(root
, parent
, pslot
+ 1);
999 btrfs_tree_lock(right
);
1000 btrfs_set_lock_blocking(right
);
1001 wret
= btrfs_cow_block(trans
, root
, right
,
1002 parent
, pslot
+ 1, &right
);
1009 /* first, try to make some room in the middle buffer */
1011 orig_slot
+= btrfs_header_nritems(left
);
1012 wret
= push_node_left(trans
, root
, left
, mid
, 1);
1015 btrfs_header_nritems(mid
);
1019 * then try to empty the right most buffer into the middle
1022 wret
= push_node_left(trans
, root
, mid
, right
, 1);
1023 if (wret
< 0 && wret
!= -ENOSPC
)
1025 if (btrfs_header_nritems(right
) == 0) {
1026 clean_tree_block(trans
, root
, right
);
1027 btrfs_tree_unlock(right
);
1028 del_ptr(trans
, root
, path
, level
+ 1, pslot
+ 1);
1029 root_sub_used(root
, right
->len
);
1030 btrfs_free_tree_block(trans
, root
, right
, 0, 1, 0);
1031 free_extent_buffer(right
);
1034 struct btrfs_disk_key right_key
;
1035 btrfs_node_key(right
, &right_key
, 0);
1036 btrfs_set_node_key(parent
, &right_key
, pslot
+ 1);
1037 btrfs_mark_buffer_dirty(parent
);
1040 if (btrfs_header_nritems(mid
) == 1) {
1042 * we're not allowed to leave a node with one item in the
1043 * tree during a delete. A deletion from lower in the tree
1044 * could try to delete the only pointer in this node.
1045 * So, pull some keys from the left.
1046 * There has to be a left pointer at this point because
1047 * otherwise we would have pulled some pointers from the
1052 btrfs_std_error(root
->fs_info
, ret
);
1055 wret
= balance_node_right(trans
, root
, mid
, left
);
1061 wret
= push_node_left(trans
, root
, left
, mid
, 1);
1067 if (btrfs_header_nritems(mid
) == 0) {
1068 clean_tree_block(trans
, root
, mid
);
1069 btrfs_tree_unlock(mid
);
1070 del_ptr(trans
, root
, path
, level
+ 1, pslot
);
1071 root_sub_used(root
, mid
->len
);
1072 btrfs_free_tree_block(trans
, root
, mid
, 0, 1, 0);
1073 free_extent_buffer(mid
);
1076 /* update the parent key to reflect our changes */
1077 struct btrfs_disk_key mid_key
;
1078 btrfs_node_key(mid
, &mid_key
, 0);
1079 btrfs_set_node_key(parent
, &mid_key
, pslot
);
1080 btrfs_mark_buffer_dirty(parent
);
1083 /* update the path */
1085 if (btrfs_header_nritems(left
) > orig_slot
) {
1086 extent_buffer_get(left
);
1087 /* left was locked after cow */
1088 path
->nodes
[level
] = left
;
1089 path
->slots
[level
+ 1] -= 1;
1090 path
->slots
[level
] = orig_slot
;
1092 btrfs_tree_unlock(mid
);
1093 free_extent_buffer(mid
);
1096 orig_slot
-= btrfs_header_nritems(left
);
1097 path
->slots
[level
] = orig_slot
;
1100 /* double check we haven't messed things up */
1102 btrfs_node_blockptr(path
->nodes
[level
], path
->slots
[level
]))
1106 btrfs_tree_unlock(right
);
1107 free_extent_buffer(right
);
1110 if (path
->nodes
[level
] != left
)
1111 btrfs_tree_unlock(left
);
1112 free_extent_buffer(left
);
1117 /* Node balancing for insertion. Here we only split or push nodes around
1118 * when they are completely full. This is also done top down, so we
1119 * have to be pessimistic.
1121 static noinline
int push_nodes_for_insert(struct btrfs_trans_handle
*trans
,
1122 struct btrfs_root
*root
,
1123 struct btrfs_path
*path
, int level
)
1125 struct extent_buffer
*right
= NULL
;
1126 struct extent_buffer
*mid
;
1127 struct extent_buffer
*left
= NULL
;
1128 struct extent_buffer
*parent
= NULL
;
1132 int orig_slot
= path
->slots
[level
];
1137 mid
= path
->nodes
[level
];
1138 WARN_ON(btrfs_header_generation(mid
) != trans
->transid
);
1140 if (level
< BTRFS_MAX_LEVEL
- 1) {
1141 parent
= path
->nodes
[level
+ 1];
1142 pslot
= path
->slots
[level
+ 1];
1148 left
= read_node_slot(root
, parent
, pslot
- 1);
1150 /* first, try to make some room in the middle buffer */
1154 btrfs_tree_lock(left
);
1155 btrfs_set_lock_blocking(left
);
1157 left_nr
= btrfs_header_nritems(left
);
1158 if (left_nr
>= BTRFS_NODEPTRS_PER_BLOCK(root
) - 1) {
1161 ret
= btrfs_cow_block(trans
, root
, left
, parent
,
1166 wret
= push_node_left(trans
, root
,
1173 struct btrfs_disk_key disk_key
;
1174 orig_slot
+= left_nr
;
1175 btrfs_node_key(mid
, &disk_key
, 0);
1176 btrfs_set_node_key(parent
, &disk_key
, pslot
);
1177 btrfs_mark_buffer_dirty(parent
);
1178 if (btrfs_header_nritems(left
) > orig_slot
) {
1179 path
->nodes
[level
] = left
;
1180 path
->slots
[level
+ 1] -= 1;
1181 path
->slots
[level
] = orig_slot
;
1182 btrfs_tree_unlock(mid
);
1183 free_extent_buffer(mid
);
1186 btrfs_header_nritems(left
);
1187 path
->slots
[level
] = orig_slot
;
1188 btrfs_tree_unlock(left
);
1189 free_extent_buffer(left
);
1193 btrfs_tree_unlock(left
);
1194 free_extent_buffer(left
);
1196 right
= read_node_slot(root
, parent
, pslot
+ 1);
1199 * then try to empty the right most buffer into the middle
1204 btrfs_tree_lock(right
);
1205 btrfs_set_lock_blocking(right
);
1207 right_nr
= btrfs_header_nritems(right
);
1208 if (right_nr
>= BTRFS_NODEPTRS_PER_BLOCK(root
) - 1) {
1211 ret
= btrfs_cow_block(trans
, root
, right
,
1217 wret
= balance_node_right(trans
, root
,
1224 struct btrfs_disk_key disk_key
;
1226 btrfs_node_key(right
, &disk_key
, 0);
1227 btrfs_set_node_key(parent
, &disk_key
, pslot
+ 1);
1228 btrfs_mark_buffer_dirty(parent
);
1230 if (btrfs_header_nritems(mid
) <= orig_slot
) {
1231 path
->nodes
[level
] = right
;
1232 path
->slots
[level
+ 1] += 1;
1233 path
->slots
[level
] = orig_slot
-
1234 btrfs_header_nritems(mid
);
1235 btrfs_tree_unlock(mid
);
1236 free_extent_buffer(mid
);
1238 btrfs_tree_unlock(right
);
1239 free_extent_buffer(right
);
1243 btrfs_tree_unlock(right
);
1244 free_extent_buffer(right
);
1250 * readahead one full node of leaves, finding things that are close
1251 * to the block in 'slot', and triggering ra on them.
1253 static void reada_for_search(struct btrfs_root
*root
,
1254 struct btrfs_path
*path
,
1255 int level
, int slot
, u64 objectid
)
1257 struct extent_buffer
*node
;
1258 struct btrfs_disk_key disk_key
;
1264 int direction
= path
->reada
;
1265 struct extent_buffer
*eb
;
1273 if (!path
->nodes
[level
])
1276 node
= path
->nodes
[level
];
1278 search
= btrfs_node_blockptr(node
, slot
);
1279 blocksize
= btrfs_level_size(root
, level
- 1);
1280 eb
= btrfs_find_tree_block(root
, search
, blocksize
);
1282 free_extent_buffer(eb
);
1288 nritems
= btrfs_header_nritems(node
);
1292 if (direction
< 0) {
1296 } else if (direction
> 0) {
1301 if (path
->reada
< 0 && objectid
) {
1302 btrfs_node_key(node
, &disk_key
, nr
);
1303 if (btrfs_disk_key_objectid(&disk_key
) != objectid
)
1306 search
= btrfs_node_blockptr(node
, nr
);
1307 if ((search
<= target
&& target
- search
<= 65536) ||
1308 (search
> target
&& search
- target
<= 65536)) {
1309 gen
= btrfs_node_ptr_generation(node
, nr
);
1310 readahead_tree_block(root
, search
, blocksize
, gen
);
1314 if ((nread
> 65536 || nscan
> 32))
1320 * returns -EAGAIN if it had to drop the path, or zero if everything was in
1323 static noinline
int reada_for_balance(struct btrfs_root
*root
,
1324 struct btrfs_path
*path
, int level
)
1328 struct extent_buffer
*parent
;
1329 struct extent_buffer
*eb
;
1336 parent
= path
->nodes
[level
+ 1];
1340 nritems
= btrfs_header_nritems(parent
);
1341 slot
= path
->slots
[level
+ 1];
1342 blocksize
= btrfs_level_size(root
, level
);
1345 block1
= btrfs_node_blockptr(parent
, slot
- 1);
1346 gen
= btrfs_node_ptr_generation(parent
, slot
- 1);
1347 eb
= btrfs_find_tree_block(root
, block1
, blocksize
);
1348 if (eb
&& btrfs_buffer_uptodate(eb
, gen
))
1350 free_extent_buffer(eb
);
1352 if (slot
+ 1 < nritems
) {
1353 block2
= btrfs_node_blockptr(parent
, slot
+ 1);
1354 gen
= btrfs_node_ptr_generation(parent
, slot
+ 1);
1355 eb
= btrfs_find_tree_block(root
, block2
, blocksize
);
1356 if (eb
&& btrfs_buffer_uptodate(eb
, gen
))
1358 free_extent_buffer(eb
);
1360 if (block1
|| block2
) {
1363 /* release the whole path */
1364 btrfs_release_path(path
);
1366 /* read the blocks */
1368 readahead_tree_block(root
, block1
, blocksize
, 0);
1370 readahead_tree_block(root
, block2
, blocksize
, 0);
1373 eb
= read_tree_block(root
, block1
, blocksize
, 0);
1374 free_extent_buffer(eb
);
1377 eb
= read_tree_block(root
, block2
, blocksize
, 0);
1378 free_extent_buffer(eb
);
1386 * when we walk down the tree, it is usually safe to unlock the higher layers
1387 * in the tree. The exceptions are when our path goes through slot 0, because
1388 * operations on the tree might require changing key pointers higher up in the
1391 * callers might also have set path->keep_locks, which tells this code to keep
1392 * the lock if the path points to the last slot in the block. This is part of
1393 * walking through the tree, and selecting the next slot in the higher block.
1395 * lowest_unlock sets the lowest level in the tree we're allowed to unlock. so
1396 * if lowest_unlock is 1, level 0 won't be unlocked
1398 static noinline
void unlock_up(struct btrfs_path
*path
, int level
,
1402 int skip_level
= level
;
1404 struct extent_buffer
*t
;
1406 for (i
= level
; i
< BTRFS_MAX_LEVEL
; i
++) {
1407 if (!path
->nodes
[i
])
1409 if (!path
->locks
[i
])
1411 if (!no_skips
&& path
->slots
[i
] == 0) {
1415 if (!no_skips
&& path
->keep_locks
) {
1418 nritems
= btrfs_header_nritems(t
);
1419 if (nritems
< 1 || path
->slots
[i
] >= nritems
- 1) {
1424 if (skip_level
< i
&& i
>= lowest_unlock
)
1428 if (i
>= lowest_unlock
&& i
> skip_level
&& path
->locks
[i
]) {
1429 btrfs_tree_unlock_rw(t
, path
->locks
[i
]);
1436 * This releases any locks held in the path starting at level and
1437 * going all the way up to the root.
1439 * btrfs_search_slot will keep the lock held on higher nodes in a few
1440 * corner cases, such as COW of the block at slot zero in the node. This
1441 * ignores those rules, and it should only be called when there are no
1442 * more updates to be done higher up in the tree.
1444 noinline
void btrfs_unlock_up_safe(struct btrfs_path
*path
, int level
)
1448 if (path
->keep_locks
)
1451 for (i
= level
; i
< BTRFS_MAX_LEVEL
; i
++) {
1452 if (!path
->nodes
[i
])
1454 if (!path
->locks
[i
])
1456 btrfs_tree_unlock_rw(path
->nodes
[i
], path
->locks
[i
]);
1462 * helper function for btrfs_search_slot. The goal is to find a block
1463 * in cache without setting the path to blocking. If we find the block
1464 * we return zero and the path is unchanged.
1466 * If we can't find the block, we set the path blocking and do some
1467 * reada. -EAGAIN is returned and the search must be repeated.
1470 read_block_for_search(struct btrfs_trans_handle
*trans
,
1471 struct btrfs_root
*root
, struct btrfs_path
*p
,
1472 struct extent_buffer
**eb_ret
, int level
, int slot
,
1473 struct btrfs_key
*key
)
1478 struct extent_buffer
*b
= *eb_ret
;
1479 struct extent_buffer
*tmp
;
1482 blocknr
= btrfs_node_blockptr(b
, slot
);
1483 gen
= btrfs_node_ptr_generation(b
, slot
);
1484 blocksize
= btrfs_level_size(root
, level
- 1);
1486 tmp
= btrfs_find_tree_block(root
, blocknr
, blocksize
);
1488 if (btrfs_buffer_uptodate(tmp
, 0)) {
1489 if (btrfs_buffer_uptodate(tmp
, gen
)) {
1491 * we found an up to date block without
1498 /* the pages were up to date, but we failed
1499 * the generation number check. Do a full
1500 * read for the generation number that is correct.
1501 * We must do this without dropping locks so
1502 * we can trust our generation number
1504 free_extent_buffer(tmp
);
1505 btrfs_set_path_blocking(p
);
1507 tmp
= read_tree_block(root
, blocknr
, blocksize
, gen
);
1508 if (tmp
&& btrfs_buffer_uptodate(tmp
, gen
)) {
1512 free_extent_buffer(tmp
);
1513 btrfs_release_path(p
);
1519 * reduce lock contention at high levels
1520 * of the btree by dropping locks before
1521 * we read. Don't release the lock on the current
1522 * level because we need to walk this node to figure
1523 * out which blocks to read.
1525 btrfs_unlock_up_safe(p
, level
+ 1);
1526 btrfs_set_path_blocking(p
);
1528 free_extent_buffer(tmp
);
1530 reada_for_search(root
, p
, level
, slot
, key
->objectid
);
1532 btrfs_release_path(p
);
1535 tmp
= read_tree_block(root
, blocknr
, blocksize
, 0);
1538 * If the read above didn't mark this buffer up to date,
1539 * it will never end up being up to date. Set ret to EIO now
1540 * and give up so that our caller doesn't loop forever
1543 if (!btrfs_buffer_uptodate(tmp
, 0))
1545 free_extent_buffer(tmp
);
1551 * helper function for btrfs_search_slot. This does all of the checks
1552 * for node-level blocks and does any balancing required based on
1555 * If no extra work was required, zero is returned. If we had to
1556 * drop the path, -EAGAIN is returned and btrfs_search_slot must
1560 setup_nodes_for_search(struct btrfs_trans_handle
*trans
,
1561 struct btrfs_root
*root
, struct btrfs_path
*p
,
1562 struct extent_buffer
*b
, int level
, int ins_len
,
1563 int *write_lock_level
)
1566 if ((p
->search_for_split
|| ins_len
> 0) && btrfs_header_nritems(b
) >=
1567 BTRFS_NODEPTRS_PER_BLOCK(root
) - 3) {
1570 if (*write_lock_level
< level
+ 1) {
1571 *write_lock_level
= level
+ 1;
1572 btrfs_release_path(p
);
1576 sret
= reada_for_balance(root
, p
, level
);
1580 btrfs_set_path_blocking(p
);
1581 sret
= split_node(trans
, root
, p
, level
);
1582 btrfs_clear_path_blocking(p
, NULL
, 0);
1589 b
= p
->nodes
[level
];
1590 } else if (ins_len
< 0 && btrfs_header_nritems(b
) <
1591 BTRFS_NODEPTRS_PER_BLOCK(root
) / 2) {
1594 if (*write_lock_level
< level
+ 1) {
1595 *write_lock_level
= level
+ 1;
1596 btrfs_release_path(p
);
1600 sret
= reada_for_balance(root
, p
, level
);
1604 btrfs_set_path_blocking(p
);
1605 sret
= balance_level(trans
, root
, p
, level
);
1606 btrfs_clear_path_blocking(p
, NULL
, 0);
1612 b
= p
->nodes
[level
];
1614 btrfs_release_path(p
);
1617 BUG_ON(btrfs_header_nritems(b
) == 1);
1628 * look for key in the tree. path is filled in with nodes along the way
1629 * if key is found, we return zero and you can find the item in the leaf
1630 * level of the path (level 0)
1632 * If the key isn't found, the path points to the slot where it should
1633 * be inserted, and 1 is returned. If there are other errors during the
1634 * search a negative error number is returned.
1636 * if ins_len > 0, nodes and leaves will be split as we walk down the
1637 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
1640 int btrfs_search_slot(struct btrfs_trans_handle
*trans
, struct btrfs_root
1641 *root
, struct btrfs_key
*key
, struct btrfs_path
*p
, int
1644 struct extent_buffer
*b
;
1649 int lowest_unlock
= 1;
1651 /* everything at write_lock_level or lower must be write locked */
1652 int write_lock_level
= 0;
1653 u8 lowest_level
= 0;
1655 lowest_level
= p
->lowest_level
;
1656 WARN_ON(lowest_level
&& ins_len
> 0);
1657 WARN_ON(p
->nodes
[0] != NULL
);
1662 /* when we are removing items, we might have to go up to level
1663 * two as we update tree pointers Make sure we keep write
1664 * for those levels as well
1666 write_lock_level
= 2;
1667 } else if (ins_len
> 0) {
1669 * for inserting items, make sure we have a write lock on
1670 * level 1 so we can update keys
1672 write_lock_level
= 1;
1676 write_lock_level
= -1;
1678 if (cow
&& (p
->keep_locks
|| p
->lowest_level
))
1679 write_lock_level
= BTRFS_MAX_LEVEL
;
1683 * we try very hard to do read locks on the root
1685 root_lock
= BTRFS_READ_LOCK
;
1687 if (p
->search_commit_root
) {
1689 * the commit roots are read only
1690 * so we always do read locks
1692 b
= root
->commit_root
;
1693 extent_buffer_get(b
);
1694 level
= btrfs_header_level(b
);
1695 if (!p
->skip_locking
)
1696 btrfs_tree_read_lock(b
);
1698 if (p
->skip_locking
) {
1699 b
= btrfs_root_node(root
);
1700 level
= btrfs_header_level(b
);
1702 /* we don't know the level of the root node
1703 * until we actually have it read locked
1705 b
= btrfs_read_lock_root_node(root
);
1706 level
= btrfs_header_level(b
);
1707 if (level
<= write_lock_level
) {
1708 /* whoops, must trade for write lock */
1709 btrfs_tree_read_unlock(b
);
1710 free_extent_buffer(b
);
1711 b
= btrfs_lock_root_node(root
);
1712 root_lock
= BTRFS_WRITE_LOCK
;
1714 /* the level might have changed, check again */
1715 level
= btrfs_header_level(b
);
1719 p
->nodes
[level
] = b
;
1720 if (!p
->skip_locking
)
1721 p
->locks
[level
] = root_lock
;
1724 level
= btrfs_header_level(b
);
1727 * setup the path here so we can release it under lock
1728 * contention with the cow code
1732 * if we don't really need to cow this block
1733 * then we don't want to set the path blocking,
1734 * so we test it here
1736 if (!should_cow_block(trans
, root
, b
))
1739 btrfs_set_path_blocking(p
);
1742 * must have write locks on this node and the
1745 if (level
+ 1 > write_lock_level
) {
1746 write_lock_level
= level
+ 1;
1747 btrfs_release_path(p
);
1751 err
= btrfs_cow_block(trans
, root
, b
,
1752 p
->nodes
[level
+ 1],
1753 p
->slots
[level
+ 1], &b
);
1760 BUG_ON(!cow
&& ins_len
);
1762 p
->nodes
[level
] = b
;
1763 btrfs_clear_path_blocking(p
, NULL
, 0);
1766 * we have a lock on b and as long as we aren't changing
1767 * the tree, there is no way to for the items in b to change.
1768 * It is safe to drop the lock on our parent before we
1769 * go through the expensive btree search on b.
1771 * If cow is true, then we might be changing slot zero,
1772 * which may require changing the parent. So, we can't
1773 * drop the lock until after we know which slot we're
1777 btrfs_unlock_up_safe(p
, level
+ 1);
1779 ret
= bin_search(b
, key
, level
, &slot
);
1783 if (ret
&& slot
> 0) {
1787 p
->slots
[level
] = slot
;
1788 err
= setup_nodes_for_search(trans
, root
, p
, b
, level
,
1789 ins_len
, &write_lock_level
);
1796 b
= p
->nodes
[level
];
1797 slot
= p
->slots
[level
];
1800 * slot 0 is special, if we change the key
1801 * we have to update the parent pointer
1802 * which means we must have a write lock
1805 if (slot
== 0 && cow
&&
1806 write_lock_level
< level
+ 1) {
1807 write_lock_level
= level
+ 1;
1808 btrfs_release_path(p
);
1812 unlock_up(p
, level
, lowest_unlock
);
1814 if (level
== lowest_level
) {
1820 err
= read_block_for_search(trans
, root
, p
,
1821 &b
, level
, slot
, key
);
1829 if (!p
->skip_locking
) {
1830 level
= btrfs_header_level(b
);
1831 if (level
<= write_lock_level
) {
1832 err
= btrfs_try_tree_write_lock(b
);
1834 btrfs_set_path_blocking(p
);
1836 btrfs_clear_path_blocking(p
, b
,
1839 p
->locks
[level
] = BTRFS_WRITE_LOCK
;
1841 err
= btrfs_try_tree_read_lock(b
);
1843 btrfs_set_path_blocking(p
);
1844 btrfs_tree_read_lock(b
);
1845 btrfs_clear_path_blocking(p
, b
,
1848 p
->locks
[level
] = BTRFS_READ_LOCK
;
1850 p
->nodes
[level
] = b
;
1853 p
->slots
[level
] = slot
;
1855 btrfs_leaf_free_space(root
, b
) < ins_len
) {
1856 if (write_lock_level
< 1) {
1857 write_lock_level
= 1;
1858 btrfs_release_path(p
);
1862 btrfs_set_path_blocking(p
);
1863 err
= split_leaf(trans
, root
, key
,
1864 p
, ins_len
, ret
== 0);
1865 btrfs_clear_path_blocking(p
, NULL
, 0);
1873 if (!p
->search_for_split
)
1874 unlock_up(p
, level
, lowest_unlock
);
1881 * we don't really know what they plan on doing with the path
1882 * from here on, so for now just mark it as blocking
1884 if (!p
->leave_spinning
)
1885 btrfs_set_path_blocking(p
);
1887 btrfs_release_path(p
);
1892 * adjust the pointers going up the tree, starting at level
1893 * making sure the right key of each node is points to 'key'.
1894 * This is used after shifting pointers to the left, so it stops
1895 * fixing up pointers when a given leaf/node is not in slot 0 of the
1899 static void fixup_low_keys(struct btrfs_trans_handle
*trans
,
1900 struct btrfs_root
*root
, struct btrfs_path
*path
,
1901 struct btrfs_disk_key
*key
, int level
)
1904 struct extent_buffer
*t
;
1906 for (i
= level
; i
< BTRFS_MAX_LEVEL
; i
++) {
1907 int tslot
= path
->slots
[i
];
1908 if (!path
->nodes
[i
])
1911 btrfs_set_node_key(t
, key
, tslot
);
1912 btrfs_mark_buffer_dirty(path
->nodes
[i
]);
1921 * This function isn't completely safe. It's the caller's responsibility
1922 * that the new key won't break the order
1924 void btrfs_set_item_key_safe(struct btrfs_trans_handle
*trans
,
1925 struct btrfs_root
*root
, struct btrfs_path
*path
,
1926 struct btrfs_key
*new_key
)
1928 struct btrfs_disk_key disk_key
;
1929 struct extent_buffer
*eb
;
1932 eb
= path
->nodes
[0];
1933 slot
= path
->slots
[0];
1935 btrfs_item_key(eb
, &disk_key
, slot
- 1);
1936 BUG_ON(comp_keys(&disk_key
, new_key
) >= 0);
1938 if (slot
< btrfs_header_nritems(eb
) - 1) {
1939 btrfs_item_key(eb
, &disk_key
, slot
+ 1);
1940 BUG_ON(comp_keys(&disk_key
, new_key
) <= 0);
1943 btrfs_cpu_key_to_disk(&disk_key
, new_key
);
1944 btrfs_set_item_key(eb
, &disk_key
, slot
);
1945 btrfs_mark_buffer_dirty(eb
);
1947 fixup_low_keys(trans
, root
, path
, &disk_key
, 1);
1951 * try to push data from one node into the next node left in the
1954 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1955 * error, and > 0 if there was no room in the left hand block.
1957 static int push_node_left(struct btrfs_trans_handle
*trans
,
1958 struct btrfs_root
*root
, struct extent_buffer
*dst
,
1959 struct extent_buffer
*src
, int empty
)
1966 src_nritems
= btrfs_header_nritems(src
);
1967 dst_nritems
= btrfs_header_nritems(dst
);
1968 push_items
= BTRFS_NODEPTRS_PER_BLOCK(root
) - dst_nritems
;
1969 WARN_ON(btrfs_header_generation(src
) != trans
->transid
);
1970 WARN_ON(btrfs_header_generation(dst
) != trans
->transid
);
1972 if (!empty
&& src_nritems
<= 8)
1975 if (push_items
<= 0)
1979 push_items
= min(src_nritems
, push_items
);
1980 if (push_items
< src_nritems
) {
1981 /* leave at least 8 pointers in the node if
1982 * we aren't going to empty it
1984 if (src_nritems
- push_items
< 8) {
1985 if (push_items
<= 8)
1991 push_items
= min(src_nritems
- 8, push_items
);
1993 copy_extent_buffer(dst
, src
,
1994 btrfs_node_key_ptr_offset(dst_nritems
),
1995 btrfs_node_key_ptr_offset(0),
1996 push_items
* sizeof(struct btrfs_key_ptr
));
1998 if (push_items
< src_nritems
) {
1999 memmove_extent_buffer(src
, btrfs_node_key_ptr_offset(0),
2000 btrfs_node_key_ptr_offset(push_items
),
2001 (src_nritems
- push_items
) *
2002 sizeof(struct btrfs_key_ptr
));
2004 btrfs_set_header_nritems(src
, src_nritems
- push_items
);
2005 btrfs_set_header_nritems(dst
, dst_nritems
+ push_items
);
2006 btrfs_mark_buffer_dirty(src
);
2007 btrfs_mark_buffer_dirty(dst
);
2013 * try to push data from one node into the next node right in the
2016 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
2017 * error, and > 0 if there was no room in the right hand block.
2019 * this will only push up to 1/2 the contents of the left node over
2021 static int balance_node_right(struct btrfs_trans_handle
*trans
,
2022 struct btrfs_root
*root
,
2023 struct extent_buffer
*dst
,
2024 struct extent_buffer
*src
)
2032 WARN_ON(btrfs_header_generation(src
) != trans
->transid
);
2033 WARN_ON(btrfs_header_generation(dst
) != trans
->transid
);
2035 src_nritems
= btrfs_header_nritems(src
);
2036 dst_nritems
= btrfs_header_nritems(dst
);
2037 push_items
= BTRFS_NODEPTRS_PER_BLOCK(root
) - dst_nritems
;
2038 if (push_items
<= 0)
2041 if (src_nritems
< 4)
2044 max_push
= src_nritems
/ 2 + 1;
2045 /* don't try to empty the node */
2046 if (max_push
>= src_nritems
)
2049 if (max_push
< push_items
)
2050 push_items
= max_push
;
2052 memmove_extent_buffer(dst
, btrfs_node_key_ptr_offset(push_items
),
2053 btrfs_node_key_ptr_offset(0),
2055 sizeof(struct btrfs_key_ptr
));
2057 copy_extent_buffer(dst
, src
,
2058 btrfs_node_key_ptr_offset(0),
2059 btrfs_node_key_ptr_offset(src_nritems
- push_items
),
2060 push_items
* sizeof(struct btrfs_key_ptr
));
2062 btrfs_set_header_nritems(src
, src_nritems
- push_items
);
2063 btrfs_set_header_nritems(dst
, dst_nritems
+ push_items
);
2065 btrfs_mark_buffer_dirty(src
);
2066 btrfs_mark_buffer_dirty(dst
);
2072 * helper function to insert a new root level in the tree.
2073 * A new node is allocated, and a single item is inserted to
2074 * point to the existing root
2076 * returns zero on success or < 0 on failure.
2078 static noinline
int insert_new_root(struct btrfs_trans_handle
*trans
,
2079 struct btrfs_root
*root
,
2080 struct btrfs_path
*path
, int level
)
2083 struct extent_buffer
*lower
;
2084 struct extent_buffer
*c
;
2085 struct extent_buffer
*old
;
2086 struct btrfs_disk_key lower_key
;
2088 BUG_ON(path
->nodes
[level
]);
2089 BUG_ON(path
->nodes
[level
-1] != root
->node
);
2091 lower
= path
->nodes
[level
-1];
2093 btrfs_item_key(lower
, &lower_key
, 0);
2095 btrfs_node_key(lower
, &lower_key
, 0);
2097 c
= btrfs_alloc_free_block(trans
, root
, root
->nodesize
, 0,
2098 root
->root_key
.objectid
, &lower_key
,
2099 level
, root
->node
->start
, 0, 0);
2103 root_add_used(root
, root
->nodesize
);
2105 memset_extent_buffer(c
, 0, 0, sizeof(struct btrfs_header
));
2106 btrfs_set_header_nritems(c
, 1);
2107 btrfs_set_header_level(c
, level
);
2108 btrfs_set_header_bytenr(c
, c
->start
);
2109 btrfs_set_header_generation(c
, trans
->transid
);
2110 btrfs_set_header_backref_rev(c
, BTRFS_MIXED_BACKREF_REV
);
2111 btrfs_set_header_owner(c
, root
->root_key
.objectid
);
2113 write_extent_buffer(c
, root
->fs_info
->fsid
,
2114 (unsigned long)btrfs_header_fsid(c
),
2117 write_extent_buffer(c
, root
->fs_info
->chunk_tree_uuid
,
2118 (unsigned long)btrfs_header_chunk_tree_uuid(c
),
2121 btrfs_set_node_key(c
, &lower_key
, 0);
2122 btrfs_set_node_blockptr(c
, 0, lower
->start
);
2123 lower_gen
= btrfs_header_generation(lower
);
2124 WARN_ON(lower_gen
!= trans
->transid
);
2126 btrfs_set_node_ptr_generation(c
, 0, lower_gen
);
2128 btrfs_mark_buffer_dirty(c
);
2131 rcu_assign_pointer(root
->node
, c
);
2133 /* the super has an extra ref to root->node */
2134 free_extent_buffer(old
);
2136 add_root_to_dirty_list(root
);
2137 extent_buffer_get(c
);
2138 path
->nodes
[level
] = c
;
2139 path
->locks
[level
] = BTRFS_WRITE_LOCK
;
2140 path
->slots
[level
] = 0;
2145 * worker function to insert a single pointer in a node.
2146 * the node should have enough room for the pointer already
2148 * slot and level indicate where you want the key to go, and
2149 * blocknr is the block the key points to.
2151 static void insert_ptr(struct btrfs_trans_handle
*trans
,
2152 struct btrfs_root
*root
, struct btrfs_path
*path
,
2153 struct btrfs_disk_key
*key
, u64 bytenr
,
2154 int slot
, int level
)
2156 struct extent_buffer
*lower
;
2159 BUG_ON(!path
->nodes
[level
]);
2160 btrfs_assert_tree_locked(path
->nodes
[level
]);
2161 lower
= path
->nodes
[level
];
2162 nritems
= btrfs_header_nritems(lower
);
2163 BUG_ON(slot
> nritems
);
2164 BUG_ON(nritems
== BTRFS_NODEPTRS_PER_BLOCK(root
));
2165 if (slot
!= nritems
) {
2166 memmove_extent_buffer(lower
,
2167 btrfs_node_key_ptr_offset(slot
+ 1),
2168 btrfs_node_key_ptr_offset(slot
),
2169 (nritems
- slot
) * sizeof(struct btrfs_key_ptr
));
2171 btrfs_set_node_key(lower
, key
, slot
);
2172 btrfs_set_node_blockptr(lower
, slot
, bytenr
);
2173 WARN_ON(trans
->transid
== 0);
2174 btrfs_set_node_ptr_generation(lower
, slot
, trans
->transid
);
2175 btrfs_set_header_nritems(lower
, nritems
+ 1);
2176 btrfs_mark_buffer_dirty(lower
);
2180 * split the node at the specified level in path in two.
2181 * The path is corrected to point to the appropriate node after the split
2183 * Before splitting this tries to make some room in the node by pushing
2184 * left and right, if either one works, it returns right away.
2186 * returns 0 on success and < 0 on failure
2188 static noinline
int split_node(struct btrfs_trans_handle
*trans
,
2189 struct btrfs_root
*root
,
2190 struct btrfs_path
*path
, int level
)
2192 struct extent_buffer
*c
;
2193 struct extent_buffer
*split
;
2194 struct btrfs_disk_key disk_key
;
2199 c
= path
->nodes
[level
];
2200 WARN_ON(btrfs_header_generation(c
) != trans
->transid
);
2201 if (c
== root
->node
) {
2202 /* trying to split the root, lets make a new one */
2203 ret
= insert_new_root(trans
, root
, path
, level
+ 1);
2207 ret
= push_nodes_for_insert(trans
, root
, path
, level
);
2208 c
= path
->nodes
[level
];
2209 if (!ret
&& btrfs_header_nritems(c
) <
2210 BTRFS_NODEPTRS_PER_BLOCK(root
) - 3)
2216 c_nritems
= btrfs_header_nritems(c
);
2217 mid
= (c_nritems
+ 1) / 2;
2218 btrfs_node_key(c
, &disk_key
, mid
);
2220 split
= btrfs_alloc_free_block(trans
, root
, root
->nodesize
, 0,
2221 root
->root_key
.objectid
,
2222 &disk_key
, level
, c
->start
, 0, 0);
2224 return PTR_ERR(split
);
2226 root_add_used(root
, root
->nodesize
);
2228 memset_extent_buffer(split
, 0, 0, sizeof(struct btrfs_header
));
2229 btrfs_set_header_level(split
, btrfs_header_level(c
));
2230 btrfs_set_header_bytenr(split
, split
->start
);
2231 btrfs_set_header_generation(split
, trans
->transid
);
2232 btrfs_set_header_backref_rev(split
, BTRFS_MIXED_BACKREF_REV
);
2233 btrfs_set_header_owner(split
, root
->root_key
.objectid
);
2234 write_extent_buffer(split
, root
->fs_info
->fsid
,
2235 (unsigned long)btrfs_header_fsid(split
),
2237 write_extent_buffer(split
, root
->fs_info
->chunk_tree_uuid
,
2238 (unsigned long)btrfs_header_chunk_tree_uuid(split
),
2242 copy_extent_buffer(split
, c
,
2243 btrfs_node_key_ptr_offset(0),
2244 btrfs_node_key_ptr_offset(mid
),
2245 (c_nritems
- mid
) * sizeof(struct btrfs_key_ptr
));
2246 btrfs_set_header_nritems(split
, c_nritems
- mid
);
2247 btrfs_set_header_nritems(c
, mid
);
2250 btrfs_mark_buffer_dirty(c
);
2251 btrfs_mark_buffer_dirty(split
);
2253 insert_ptr(trans
, root
, path
, &disk_key
, split
->start
,
2254 path
->slots
[level
+ 1] + 1, level
+ 1);
2256 if (path
->slots
[level
] >= mid
) {
2257 path
->slots
[level
] -= mid
;
2258 btrfs_tree_unlock(c
);
2259 free_extent_buffer(c
);
2260 path
->nodes
[level
] = split
;
2261 path
->slots
[level
+ 1] += 1;
2263 btrfs_tree_unlock(split
);
2264 free_extent_buffer(split
);
2270 * how many bytes are required to store the items in a leaf. start
2271 * and nr indicate which items in the leaf to check. This totals up the
2272 * space used both by the item structs and the item data
2274 static int leaf_space_used(struct extent_buffer
*l
, int start
, int nr
)
2277 int nritems
= btrfs_header_nritems(l
);
2278 int end
= min(nritems
, start
+ nr
) - 1;
2282 data_len
= btrfs_item_end_nr(l
, start
);
2283 data_len
= data_len
- btrfs_item_offset_nr(l
, end
);
2284 data_len
+= sizeof(struct btrfs_item
) * nr
;
2285 WARN_ON(data_len
< 0);
2290 * The space between the end of the leaf items and
2291 * the start of the leaf data. IOW, how much room
2292 * the leaf has left for both items and data
2294 noinline
int btrfs_leaf_free_space(struct btrfs_root
*root
,
2295 struct extent_buffer
*leaf
)
2297 int nritems
= btrfs_header_nritems(leaf
);
2299 ret
= BTRFS_LEAF_DATA_SIZE(root
) - leaf_space_used(leaf
, 0, nritems
);
2301 printk(KERN_CRIT
"leaf free space ret %d, leaf data size %lu, "
2302 "used %d nritems %d\n",
2303 ret
, (unsigned long) BTRFS_LEAF_DATA_SIZE(root
),
2304 leaf_space_used(leaf
, 0, nritems
), nritems
);
2310 * min slot controls the lowest index we're willing to push to the
2311 * right. We'll push up to and including min_slot, but no lower
2313 static noinline
int __push_leaf_right(struct btrfs_trans_handle
*trans
,
2314 struct btrfs_root
*root
,
2315 struct btrfs_path
*path
,
2316 int data_size
, int empty
,
2317 struct extent_buffer
*right
,
2318 int free_space
, u32 left_nritems
,
2321 struct extent_buffer
*left
= path
->nodes
[0];
2322 struct extent_buffer
*upper
= path
->nodes
[1];
2323 struct btrfs_disk_key disk_key
;
2328 struct btrfs_item
*item
;
2337 nr
= max_t(u32
, 1, min_slot
);
2339 if (path
->slots
[0] >= left_nritems
)
2340 push_space
+= data_size
;
2342 slot
= path
->slots
[1];
2343 i
= left_nritems
- 1;
2345 item
= btrfs_item_nr(left
, i
);
2347 if (!empty
&& push_items
> 0) {
2348 if (path
->slots
[0] > i
)
2350 if (path
->slots
[0] == i
) {
2351 int space
= btrfs_leaf_free_space(root
, left
);
2352 if (space
+ push_space
* 2 > free_space
)
2357 if (path
->slots
[0] == i
)
2358 push_space
+= data_size
;
2360 this_item_size
= btrfs_item_size(left
, item
);
2361 if (this_item_size
+ sizeof(*item
) + push_space
> free_space
)
2365 push_space
+= this_item_size
+ sizeof(*item
);
2371 if (push_items
== 0)
2374 if (!empty
&& push_items
== left_nritems
)
2377 /* push left to right */
2378 right_nritems
= btrfs_header_nritems(right
);
2380 push_space
= btrfs_item_end_nr(left
, left_nritems
- push_items
);
2381 push_space
-= leaf_data_end(root
, left
);
2383 /* make room in the right data area */
2384 data_end
= leaf_data_end(root
, right
);
2385 memmove_extent_buffer(right
,
2386 btrfs_leaf_data(right
) + data_end
- push_space
,
2387 btrfs_leaf_data(right
) + data_end
,
2388 BTRFS_LEAF_DATA_SIZE(root
) - data_end
);
2390 /* copy from the left data area */
2391 copy_extent_buffer(right
, left
, btrfs_leaf_data(right
) +
2392 BTRFS_LEAF_DATA_SIZE(root
) - push_space
,
2393 btrfs_leaf_data(left
) + leaf_data_end(root
, left
),
2396 memmove_extent_buffer(right
, btrfs_item_nr_offset(push_items
),
2397 btrfs_item_nr_offset(0),
2398 right_nritems
* sizeof(struct btrfs_item
));
2400 /* copy the items from left to right */
2401 copy_extent_buffer(right
, left
, btrfs_item_nr_offset(0),
2402 btrfs_item_nr_offset(left_nritems
- push_items
),
2403 push_items
* sizeof(struct btrfs_item
));
2405 /* update the item pointers */
2406 right_nritems
+= push_items
;
2407 btrfs_set_header_nritems(right
, right_nritems
);
2408 push_space
= BTRFS_LEAF_DATA_SIZE(root
);
2409 for (i
= 0; i
< right_nritems
; i
++) {
2410 item
= btrfs_item_nr(right
, i
);
2411 push_space
-= btrfs_item_size(right
, item
);
2412 btrfs_set_item_offset(right
, item
, push_space
);
2415 left_nritems
-= push_items
;
2416 btrfs_set_header_nritems(left
, left_nritems
);
2419 btrfs_mark_buffer_dirty(left
);
2421 clean_tree_block(trans
, root
, left
);
2423 btrfs_mark_buffer_dirty(right
);
2425 btrfs_item_key(right
, &disk_key
, 0);
2426 btrfs_set_node_key(upper
, &disk_key
, slot
+ 1);
2427 btrfs_mark_buffer_dirty(upper
);
2429 /* then fixup the leaf pointer in the path */
2430 if (path
->slots
[0] >= left_nritems
) {
2431 path
->slots
[0] -= left_nritems
;
2432 if (btrfs_header_nritems(path
->nodes
[0]) == 0)
2433 clean_tree_block(trans
, root
, path
->nodes
[0]);
2434 btrfs_tree_unlock(path
->nodes
[0]);
2435 free_extent_buffer(path
->nodes
[0]);
2436 path
->nodes
[0] = right
;
2437 path
->slots
[1] += 1;
2439 btrfs_tree_unlock(right
);
2440 free_extent_buffer(right
);
2445 btrfs_tree_unlock(right
);
2446 free_extent_buffer(right
);
2451 * push some data in the path leaf to the right, trying to free up at
2452 * least data_size bytes. returns zero if the push worked, nonzero otherwise
2454 * returns 1 if the push failed because the other node didn't have enough
2455 * room, 0 if everything worked out and < 0 if there were major errors.
2457 * this will push starting from min_slot to the end of the leaf. It won't
2458 * push any slot lower than min_slot
2460 static int push_leaf_right(struct btrfs_trans_handle
*trans
, struct btrfs_root
2461 *root
, struct btrfs_path
*path
,
2462 int min_data_size
, int data_size
,
2463 int empty
, u32 min_slot
)
2465 struct extent_buffer
*left
= path
->nodes
[0];
2466 struct extent_buffer
*right
;
2467 struct extent_buffer
*upper
;
2473 if (!path
->nodes
[1])
2476 slot
= path
->slots
[1];
2477 upper
= path
->nodes
[1];
2478 if (slot
>= btrfs_header_nritems(upper
) - 1)
2481 btrfs_assert_tree_locked(path
->nodes
[1]);
2483 right
= read_node_slot(root
, upper
, slot
+ 1);
2487 btrfs_tree_lock(right
);
2488 btrfs_set_lock_blocking(right
);
2490 free_space
= btrfs_leaf_free_space(root
, right
);
2491 if (free_space
< data_size
)
2494 /* cow and double check */
2495 ret
= btrfs_cow_block(trans
, root
, right
, upper
,
2500 free_space
= btrfs_leaf_free_space(root
, right
);
2501 if (free_space
< data_size
)
2504 left_nritems
= btrfs_header_nritems(left
);
2505 if (left_nritems
== 0)
2508 return __push_leaf_right(trans
, root
, path
, min_data_size
, empty
,
2509 right
, free_space
, left_nritems
, min_slot
);
2511 btrfs_tree_unlock(right
);
2512 free_extent_buffer(right
);
2517 * push some data in the path leaf to the left, trying to free up at
2518 * least data_size bytes. returns zero if the push worked, nonzero otherwise
2520 * max_slot can put a limit on how far into the leaf we'll push items. The
2521 * item at 'max_slot' won't be touched. Use (u32)-1 to make us do all the
2524 static noinline
int __push_leaf_left(struct btrfs_trans_handle
*trans
,
2525 struct btrfs_root
*root
,
2526 struct btrfs_path
*path
, int data_size
,
2527 int empty
, struct extent_buffer
*left
,
2528 int free_space
, u32 right_nritems
,
2531 struct btrfs_disk_key disk_key
;
2532 struct extent_buffer
*right
= path
->nodes
[0];
2536 struct btrfs_item
*item
;
2537 u32 old_left_nritems
;
2541 u32 old_left_item_size
;
2544 nr
= min(right_nritems
, max_slot
);
2546 nr
= min(right_nritems
- 1, max_slot
);
2548 for (i
= 0; i
< nr
; i
++) {
2549 item
= btrfs_item_nr(right
, i
);
2551 if (!empty
&& push_items
> 0) {
2552 if (path
->slots
[0] < i
)
2554 if (path
->slots
[0] == i
) {
2555 int space
= btrfs_leaf_free_space(root
, right
);
2556 if (space
+ push_space
* 2 > free_space
)
2561 if (path
->slots
[0] == i
)
2562 push_space
+= data_size
;
2564 this_item_size
= btrfs_item_size(right
, item
);
2565 if (this_item_size
+ sizeof(*item
) + push_space
> free_space
)
2569 push_space
+= this_item_size
+ sizeof(*item
);
2572 if (push_items
== 0) {
2576 if (!empty
&& push_items
== btrfs_header_nritems(right
))
2579 /* push data from right to left */
2580 copy_extent_buffer(left
, right
,
2581 btrfs_item_nr_offset(btrfs_header_nritems(left
)),
2582 btrfs_item_nr_offset(0),
2583 push_items
* sizeof(struct btrfs_item
));
2585 push_space
= BTRFS_LEAF_DATA_SIZE(root
) -
2586 btrfs_item_offset_nr(right
, push_items
- 1);
2588 copy_extent_buffer(left
, right
, btrfs_leaf_data(left
) +
2589 leaf_data_end(root
, left
) - push_space
,
2590 btrfs_leaf_data(right
) +
2591 btrfs_item_offset_nr(right
, push_items
- 1),
2593 old_left_nritems
= btrfs_header_nritems(left
);
2594 BUG_ON(old_left_nritems
<= 0);
2596 old_left_item_size
= btrfs_item_offset_nr(left
, old_left_nritems
- 1);
2597 for (i
= old_left_nritems
; i
< old_left_nritems
+ push_items
; i
++) {
2600 item
= btrfs_item_nr(left
, i
);
2602 ioff
= btrfs_item_offset(left
, item
);
2603 btrfs_set_item_offset(left
, item
,
2604 ioff
- (BTRFS_LEAF_DATA_SIZE(root
) - old_left_item_size
));
2606 btrfs_set_header_nritems(left
, old_left_nritems
+ push_items
);
2608 /* fixup right node */
2609 if (push_items
> right_nritems
) {
2610 printk(KERN_CRIT
"push items %d nr %u\n", push_items
,
2615 if (push_items
< right_nritems
) {
2616 push_space
= btrfs_item_offset_nr(right
, push_items
- 1) -
2617 leaf_data_end(root
, right
);
2618 memmove_extent_buffer(right
, btrfs_leaf_data(right
) +
2619 BTRFS_LEAF_DATA_SIZE(root
) - push_space
,
2620 btrfs_leaf_data(right
) +
2621 leaf_data_end(root
, right
), push_space
);
2623 memmove_extent_buffer(right
, btrfs_item_nr_offset(0),
2624 btrfs_item_nr_offset(push_items
),
2625 (btrfs_header_nritems(right
) - push_items
) *
2626 sizeof(struct btrfs_item
));
2628 right_nritems
-= push_items
;
2629 btrfs_set_header_nritems(right
, right_nritems
);
2630 push_space
= BTRFS_LEAF_DATA_SIZE(root
);
2631 for (i
= 0; i
< right_nritems
; i
++) {
2632 item
= btrfs_item_nr(right
, i
);
2634 push_space
= push_space
- btrfs_item_size(right
, item
);
2635 btrfs_set_item_offset(right
, item
, push_space
);
2638 btrfs_mark_buffer_dirty(left
);
2640 btrfs_mark_buffer_dirty(right
);
2642 clean_tree_block(trans
, root
, right
);
2644 btrfs_item_key(right
, &disk_key
, 0);
2645 fixup_low_keys(trans
, root
, path
, &disk_key
, 1);
2647 /* then fixup the leaf pointer in the path */
2648 if (path
->slots
[0] < push_items
) {
2649 path
->slots
[0] += old_left_nritems
;
2650 btrfs_tree_unlock(path
->nodes
[0]);
2651 free_extent_buffer(path
->nodes
[0]);
2652 path
->nodes
[0] = left
;
2653 path
->slots
[1] -= 1;
2655 btrfs_tree_unlock(left
);
2656 free_extent_buffer(left
);
2657 path
->slots
[0] -= push_items
;
2659 BUG_ON(path
->slots
[0] < 0);
2662 btrfs_tree_unlock(left
);
2663 free_extent_buffer(left
);
2668 * push some data in the path leaf to the left, trying to free up at
2669 * least data_size bytes. returns zero if the push worked, nonzero otherwise
2671 * max_slot can put a limit on how far into the leaf we'll push items. The
2672 * item at 'max_slot' won't be touched. Use (u32)-1 to make us push all the
2675 static int push_leaf_left(struct btrfs_trans_handle
*trans
, struct btrfs_root
2676 *root
, struct btrfs_path
*path
, int min_data_size
,
2677 int data_size
, int empty
, u32 max_slot
)
2679 struct extent_buffer
*right
= path
->nodes
[0];
2680 struct extent_buffer
*left
;
2686 slot
= path
->slots
[1];
2689 if (!path
->nodes
[1])
2692 right_nritems
= btrfs_header_nritems(right
);
2693 if (right_nritems
== 0)
2696 btrfs_assert_tree_locked(path
->nodes
[1]);
2698 left
= read_node_slot(root
, path
->nodes
[1], slot
- 1);
2702 btrfs_tree_lock(left
);
2703 btrfs_set_lock_blocking(left
);
2705 free_space
= btrfs_leaf_free_space(root
, left
);
2706 if (free_space
< data_size
) {
2711 /* cow and double check */
2712 ret
= btrfs_cow_block(trans
, root
, left
,
2713 path
->nodes
[1], slot
- 1, &left
);
2715 /* we hit -ENOSPC, but it isn't fatal here */
2721 free_space
= btrfs_leaf_free_space(root
, left
);
2722 if (free_space
< data_size
) {
2727 return __push_leaf_left(trans
, root
, path
, min_data_size
,
2728 empty
, left
, free_space
, right_nritems
,
2731 btrfs_tree_unlock(left
);
2732 free_extent_buffer(left
);
2737 * split the path's leaf in two, making sure there is at least data_size
2738 * available for the resulting leaf level of the path.
2740 static noinline
void copy_for_split(struct btrfs_trans_handle
*trans
,
2741 struct btrfs_root
*root
,
2742 struct btrfs_path
*path
,
2743 struct extent_buffer
*l
,
2744 struct extent_buffer
*right
,
2745 int slot
, int mid
, int nritems
)
2750 struct btrfs_disk_key disk_key
;
2752 nritems
= nritems
- mid
;
2753 btrfs_set_header_nritems(right
, nritems
);
2754 data_copy_size
= btrfs_item_end_nr(l
, mid
) - leaf_data_end(root
, l
);
2756 copy_extent_buffer(right
, l
, btrfs_item_nr_offset(0),
2757 btrfs_item_nr_offset(mid
),
2758 nritems
* sizeof(struct btrfs_item
));
2760 copy_extent_buffer(right
, l
,
2761 btrfs_leaf_data(right
) + BTRFS_LEAF_DATA_SIZE(root
) -
2762 data_copy_size
, btrfs_leaf_data(l
) +
2763 leaf_data_end(root
, l
), data_copy_size
);
2765 rt_data_off
= BTRFS_LEAF_DATA_SIZE(root
) -
2766 btrfs_item_end_nr(l
, mid
);
2768 for (i
= 0; i
< nritems
; i
++) {
2769 struct btrfs_item
*item
= btrfs_item_nr(right
, i
);
2772 ioff
= btrfs_item_offset(right
, item
);
2773 btrfs_set_item_offset(right
, item
, ioff
+ rt_data_off
);
2776 btrfs_set_header_nritems(l
, mid
);
2777 btrfs_item_key(right
, &disk_key
, 0);
2778 insert_ptr(trans
, root
, path
, &disk_key
, right
->start
,
2779 path
->slots
[1] + 1, 1);
2781 btrfs_mark_buffer_dirty(right
);
2782 btrfs_mark_buffer_dirty(l
);
2783 BUG_ON(path
->slots
[0] != slot
);
2786 btrfs_tree_unlock(path
->nodes
[0]);
2787 free_extent_buffer(path
->nodes
[0]);
2788 path
->nodes
[0] = right
;
2789 path
->slots
[0] -= mid
;
2790 path
->slots
[1] += 1;
2792 btrfs_tree_unlock(right
);
2793 free_extent_buffer(right
);
2796 BUG_ON(path
->slots
[0] < 0);
2800 * double splits happen when we need to insert a big item in the middle
2801 * of a leaf. A double split can leave us with 3 mostly empty leaves:
2802 * leaf: [ slots 0 - N] [ our target ] [ N + 1 - total in leaf ]
2805 * We avoid this by trying to push the items on either side of our target
2806 * into the adjacent leaves. If all goes well we can avoid the double split
2809 static noinline
int push_for_double_split(struct btrfs_trans_handle
*trans
,
2810 struct btrfs_root
*root
,
2811 struct btrfs_path
*path
,
2819 slot
= path
->slots
[0];
2822 * try to push all the items after our slot into the
2825 ret
= push_leaf_right(trans
, root
, path
, 1, data_size
, 0, slot
);
2832 nritems
= btrfs_header_nritems(path
->nodes
[0]);
2834 * our goal is to get our slot at the start or end of a leaf. If
2835 * we've done so we're done
2837 if (path
->slots
[0] == 0 || path
->slots
[0] == nritems
)
2840 if (btrfs_leaf_free_space(root
, path
->nodes
[0]) >= data_size
)
2843 /* try to push all the items before our slot into the next leaf */
2844 slot
= path
->slots
[0];
2845 ret
= push_leaf_left(trans
, root
, path
, 1, data_size
, 0, slot
);
2858 * split the path's leaf in two, making sure there is at least data_size
2859 * available for the resulting leaf level of the path.
2861 * returns 0 if all went well and < 0 on failure.
2863 static noinline
int split_leaf(struct btrfs_trans_handle
*trans
,
2864 struct btrfs_root
*root
,
2865 struct btrfs_key
*ins_key
,
2866 struct btrfs_path
*path
, int data_size
,
2869 struct btrfs_disk_key disk_key
;
2870 struct extent_buffer
*l
;
2874 struct extent_buffer
*right
;
2878 int num_doubles
= 0;
2879 int tried_avoid_double
= 0;
2882 slot
= path
->slots
[0];
2883 if (extend
&& data_size
+ btrfs_item_size_nr(l
, slot
) +
2884 sizeof(struct btrfs_item
) > BTRFS_LEAF_DATA_SIZE(root
))
2887 /* first try to make some room by pushing left and right */
2889 wret
= push_leaf_right(trans
, root
, path
, data_size
,
2894 wret
= push_leaf_left(trans
, root
, path
, data_size
,
2895 data_size
, 0, (u32
)-1);
2901 /* did the pushes work? */
2902 if (btrfs_leaf_free_space(root
, l
) >= data_size
)
2906 if (!path
->nodes
[1]) {
2907 ret
= insert_new_root(trans
, root
, path
, 1);
2914 slot
= path
->slots
[0];
2915 nritems
= btrfs_header_nritems(l
);
2916 mid
= (nritems
+ 1) / 2;
2920 leaf_space_used(l
, mid
, nritems
- mid
) + data_size
>
2921 BTRFS_LEAF_DATA_SIZE(root
)) {
2922 if (slot
>= nritems
) {
2926 if (mid
!= nritems
&&
2927 leaf_space_used(l
, mid
, nritems
- mid
) +
2928 data_size
> BTRFS_LEAF_DATA_SIZE(root
)) {
2929 if (data_size
&& !tried_avoid_double
)
2930 goto push_for_double
;
2936 if (leaf_space_used(l
, 0, mid
) + data_size
>
2937 BTRFS_LEAF_DATA_SIZE(root
)) {
2938 if (!extend
&& data_size
&& slot
== 0) {
2940 } else if ((extend
|| !data_size
) && slot
== 0) {
2944 if (mid
!= nritems
&&
2945 leaf_space_used(l
, mid
, nritems
- mid
) +
2946 data_size
> BTRFS_LEAF_DATA_SIZE(root
)) {
2947 if (data_size
&& !tried_avoid_double
)
2948 goto push_for_double
;
2956 btrfs_cpu_key_to_disk(&disk_key
, ins_key
);
2958 btrfs_item_key(l
, &disk_key
, mid
);
2960 right
= btrfs_alloc_free_block(trans
, root
, root
->leafsize
, 0,
2961 root
->root_key
.objectid
,
2962 &disk_key
, 0, l
->start
, 0, 0);
2964 return PTR_ERR(right
);
2966 root_add_used(root
, root
->leafsize
);
2968 memset_extent_buffer(right
, 0, 0, sizeof(struct btrfs_header
));
2969 btrfs_set_header_bytenr(right
, right
->start
);
2970 btrfs_set_header_generation(right
, trans
->transid
);
2971 btrfs_set_header_backref_rev(right
, BTRFS_MIXED_BACKREF_REV
);
2972 btrfs_set_header_owner(right
, root
->root_key
.objectid
);
2973 btrfs_set_header_level(right
, 0);
2974 write_extent_buffer(right
, root
->fs_info
->fsid
,
2975 (unsigned long)btrfs_header_fsid(right
),
2978 write_extent_buffer(right
, root
->fs_info
->chunk_tree_uuid
,
2979 (unsigned long)btrfs_header_chunk_tree_uuid(right
),
2984 btrfs_set_header_nritems(right
, 0);
2985 insert_ptr(trans
, root
, path
, &disk_key
, right
->start
,
2986 path
->slots
[1] + 1, 1);
2987 btrfs_tree_unlock(path
->nodes
[0]);
2988 free_extent_buffer(path
->nodes
[0]);
2989 path
->nodes
[0] = right
;
2991 path
->slots
[1] += 1;
2993 btrfs_set_header_nritems(right
, 0);
2994 insert_ptr(trans
, root
, path
, &disk_key
, right
->start
,
2996 btrfs_tree_unlock(path
->nodes
[0]);
2997 free_extent_buffer(path
->nodes
[0]);
2998 path
->nodes
[0] = right
;
3000 if (path
->slots
[1] == 0)
3001 fixup_low_keys(trans
, root
, path
,
3004 btrfs_mark_buffer_dirty(right
);
3008 copy_for_split(trans
, root
, path
, l
, right
, slot
, mid
, nritems
);
3011 BUG_ON(num_doubles
!= 0);
3019 push_for_double_split(trans
, root
, path
, data_size
);
3020 tried_avoid_double
= 1;
3021 if (btrfs_leaf_free_space(root
, path
->nodes
[0]) >= data_size
)
3026 static noinline
int setup_leaf_for_split(struct btrfs_trans_handle
*trans
,
3027 struct btrfs_root
*root
,
3028 struct btrfs_path
*path
, int ins_len
)
3030 struct btrfs_key key
;
3031 struct extent_buffer
*leaf
;
3032 struct btrfs_file_extent_item
*fi
;
3037 leaf
= path
->nodes
[0];
3038 btrfs_item_key_to_cpu(leaf
, &key
, path
->slots
[0]);
3040 BUG_ON(key
.type
!= BTRFS_EXTENT_DATA_KEY
&&
3041 key
.type
!= BTRFS_EXTENT_CSUM_KEY
);
3043 if (btrfs_leaf_free_space(root
, leaf
) >= ins_len
)
3046 item_size
= btrfs_item_size_nr(leaf
, path
->slots
[0]);
3047 if (key
.type
== BTRFS_EXTENT_DATA_KEY
) {
3048 fi
= btrfs_item_ptr(leaf
, path
->slots
[0],
3049 struct btrfs_file_extent_item
);
3050 extent_len
= btrfs_file_extent_num_bytes(leaf
, fi
);
3052 btrfs_release_path(path
);
3054 path
->keep_locks
= 1;
3055 path
->search_for_split
= 1;
3056 ret
= btrfs_search_slot(trans
, root
, &key
, path
, 0, 1);
3057 path
->search_for_split
= 0;
3062 leaf
= path
->nodes
[0];
3063 /* if our item isn't there or got smaller, return now */
3064 if (ret
> 0 || item_size
!= btrfs_item_size_nr(leaf
, path
->slots
[0]))
3067 /* the leaf has changed, it now has room. return now */
3068 if (btrfs_leaf_free_space(root
, path
->nodes
[0]) >= ins_len
)
3071 if (key
.type
== BTRFS_EXTENT_DATA_KEY
) {
3072 fi
= btrfs_item_ptr(leaf
, path
->slots
[0],
3073 struct btrfs_file_extent_item
);
3074 if (extent_len
!= btrfs_file_extent_num_bytes(leaf
, fi
))
3078 btrfs_set_path_blocking(path
);
3079 ret
= split_leaf(trans
, root
, &key
, path
, ins_len
, 1);
3083 path
->keep_locks
= 0;
3084 btrfs_unlock_up_safe(path
, 1);
3087 path
->keep_locks
= 0;
3091 static noinline
int split_item(struct btrfs_trans_handle
*trans
,
3092 struct btrfs_root
*root
,
3093 struct btrfs_path
*path
,
3094 struct btrfs_key
*new_key
,
3095 unsigned long split_offset
)
3097 struct extent_buffer
*leaf
;
3098 struct btrfs_item
*item
;
3099 struct btrfs_item
*new_item
;
3105 struct btrfs_disk_key disk_key
;
3107 leaf
= path
->nodes
[0];
3108 BUG_ON(btrfs_leaf_free_space(root
, leaf
) < sizeof(struct btrfs_item
));
3110 btrfs_set_path_blocking(path
);
3112 item
= btrfs_item_nr(leaf
, path
->slots
[0]);
3113 orig_offset
= btrfs_item_offset(leaf
, item
);
3114 item_size
= btrfs_item_size(leaf
, item
);
3116 buf
= kmalloc(item_size
, GFP_NOFS
);
3120 read_extent_buffer(leaf
, buf
, btrfs_item_ptr_offset(leaf
,
3121 path
->slots
[0]), item_size
);
3123 slot
= path
->slots
[0] + 1;
3124 nritems
= btrfs_header_nritems(leaf
);
3125 if (slot
!= nritems
) {
3126 /* shift the items */
3127 memmove_extent_buffer(leaf
, btrfs_item_nr_offset(slot
+ 1),
3128 btrfs_item_nr_offset(slot
),
3129 (nritems
- slot
) * sizeof(struct btrfs_item
));
3132 btrfs_cpu_key_to_disk(&disk_key
, new_key
);
3133 btrfs_set_item_key(leaf
, &disk_key
, slot
);
3135 new_item
= btrfs_item_nr(leaf
, slot
);
3137 btrfs_set_item_offset(leaf
, new_item
, orig_offset
);
3138 btrfs_set_item_size(leaf
, new_item
, item_size
- split_offset
);
3140 btrfs_set_item_offset(leaf
, item
,
3141 orig_offset
+ item_size
- split_offset
);
3142 btrfs_set_item_size(leaf
, item
, split_offset
);
3144 btrfs_set_header_nritems(leaf
, nritems
+ 1);
3146 /* write the data for the start of the original item */
3147 write_extent_buffer(leaf
, buf
,
3148 btrfs_item_ptr_offset(leaf
, path
->slots
[0]),
3151 /* write the data for the new item */
3152 write_extent_buffer(leaf
, buf
+ split_offset
,
3153 btrfs_item_ptr_offset(leaf
, slot
),
3154 item_size
- split_offset
);
3155 btrfs_mark_buffer_dirty(leaf
);
3157 BUG_ON(btrfs_leaf_free_space(root
, leaf
) < 0);
3163 * This function splits a single item into two items,
3164 * giving 'new_key' to the new item and splitting the
3165 * old one at split_offset (from the start of the item).
3167 * The path may be released by this operation. After
3168 * the split, the path is pointing to the old item. The
3169 * new item is going to be in the same node as the old one.
3171 * Note, the item being split must be smaller enough to live alone on
3172 * a tree block with room for one extra struct btrfs_item
3174 * This allows us to split the item in place, keeping a lock on the
3175 * leaf the entire time.
3177 int btrfs_split_item(struct btrfs_trans_handle
*trans
,
3178 struct btrfs_root
*root
,
3179 struct btrfs_path
*path
,
3180 struct btrfs_key
*new_key
,
3181 unsigned long split_offset
)
3184 ret
= setup_leaf_for_split(trans
, root
, path
,
3185 sizeof(struct btrfs_item
));
3189 ret
= split_item(trans
, root
, path
, new_key
, split_offset
);
3194 * This function duplicate a item, giving 'new_key' to the new item.
3195 * It guarantees both items live in the same tree leaf and the new item
3196 * is contiguous with the original item.
3198 * This allows us to split file extent in place, keeping a lock on the
3199 * leaf the entire time.
3201 int btrfs_duplicate_item(struct btrfs_trans_handle
*trans
,
3202 struct btrfs_root
*root
,
3203 struct btrfs_path
*path
,
3204 struct btrfs_key
*new_key
)
3206 struct extent_buffer
*leaf
;
3210 leaf
= path
->nodes
[0];
3211 item_size
= btrfs_item_size_nr(leaf
, path
->slots
[0]);
3212 ret
= setup_leaf_for_split(trans
, root
, path
,
3213 item_size
+ sizeof(struct btrfs_item
));
3218 setup_items_for_insert(trans
, root
, path
, new_key
, &item_size
,
3219 item_size
, item_size
+
3220 sizeof(struct btrfs_item
), 1);
3221 leaf
= path
->nodes
[0];
3222 memcpy_extent_buffer(leaf
,
3223 btrfs_item_ptr_offset(leaf
, path
->slots
[0]),
3224 btrfs_item_ptr_offset(leaf
, path
->slots
[0] - 1),
3230 * make the item pointed to by the path smaller. new_size indicates
3231 * how small to make it, and from_end tells us if we just chop bytes
3232 * off the end of the item or if we shift the item to chop bytes off
3235 void btrfs_truncate_item(struct btrfs_trans_handle
*trans
,
3236 struct btrfs_root
*root
,
3237 struct btrfs_path
*path
,
3238 u32 new_size
, int from_end
)
3241 struct extent_buffer
*leaf
;
3242 struct btrfs_item
*item
;
3244 unsigned int data_end
;
3245 unsigned int old_data_start
;
3246 unsigned int old_size
;
3247 unsigned int size_diff
;
3250 leaf
= path
->nodes
[0];
3251 slot
= path
->slots
[0];
3253 old_size
= btrfs_item_size_nr(leaf
, slot
);
3254 if (old_size
== new_size
)
3257 nritems
= btrfs_header_nritems(leaf
);
3258 data_end
= leaf_data_end(root
, leaf
);
3260 old_data_start
= btrfs_item_offset_nr(leaf
, slot
);
3262 size_diff
= old_size
- new_size
;
3265 BUG_ON(slot
>= nritems
);
3268 * item0..itemN ... dataN.offset..dataN.size .. data0.size
3270 /* first correct the data pointers */
3271 for (i
= slot
; i
< nritems
; i
++) {
3273 item
= btrfs_item_nr(leaf
, i
);
3275 ioff
= btrfs_item_offset(leaf
, item
);
3276 btrfs_set_item_offset(leaf
, item
, ioff
+ size_diff
);
3279 /* shift the data */
3281 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
3282 data_end
+ size_diff
, btrfs_leaf_data(leaf
) +
3283 data_end
, old_data_start
+ new_size
- data_end
);
3285 struct btrfs_disk_key disk_key
;
3288 btrfs_item_key(leaf
, &disk_key
, slot
);
3290 if (btrfs_disk_key_type(&disk_key
) == BTRFS_EXTENT_DATA_KEY
) {
3292 struct btrfs_file_extent_item
*fi
;
3294 fi
= btrfs_item_ptr(leaf
, slot
,
3295 struct btrfs_file_extent_item
);
3296 fi
= (struct btrfs_file_extent_item
*)(
3297 (unsigned long)fi
- size_diff
);
3299 if (btrfs_file_extent_type(leaf
, fi
) ==
3300 BTRFS_FILE_EXTENT_INLINE
) {
3301 ptr
= btrfs_item_ptr_offset(leaf
, slot
);
3302 memmove_extent_buffer(leaf
, ptr
,
3304 offsetof(struct btrfs_file_extent_item
,
3309 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
3310 data_end
+ size_diff
, btrfs_leaf_data(leaf
) +
3311 data_end
, old_data_start
- data_end
);
3313 offset
= btrfs_disk_key_offset(&disk_key
);
3314 btrfs_set_disk_key_offset(&disk_key
, offset
+ size_diff
);
3315 btrfs_set_item_key(leaf
, &disk_key
, slot
);
3317 fixup_low_keys(trans
, root
, path
, &disk_key
, 1);
3320 item
= btrfs_item_nr(leaf
, slot
);
3321 btrfs_set_item_size(leaf
, item
, new_size
);
3322 btrfs_mark_buffer_dirty(leaf
);
3324 if (btrfs_leaf_free_space(root
, leaf
) < 0) {
3325 btrfs_print_leaf(root
, leaf
);
3331 * make the item pointed to by the path bigger, data_size is the new size.
3333 void btrfs_extend_item(struct btrfs_trans_handle
*trans
,
3334 struct btrfs_root
*root
, struct btrfs_path
*path
,
3338 struct extent_buffer
*leaf
;
3339 struct btrfs_item
*item
;
3341 unsigned int data_end
;
3342 unsigned int old_data
;
3343 unsigned int old_size
;
3346 leaf
= path
->nodes
[0];
3348 nritems
= btrfs_header_nritems(leaf
);
3349 data_end
= leaf_data_end(root
, leaf
);
3351 if (btrfs_leaf_free_space(root
, leaf
) < data_size
) {
3352 btrfs_print_leaf(root
, leaf
);
3355 slot
= path
->slots
[0];
3356 old_data
= btrfs_item_end_nr(leaf
, slot
);
3359 if (slot
>= nritems
) {
3360 btrfs_print_leaf(root
, leaf
);
3361 printk(KERN_CRIT
"slot %d too large, nritems %d\n",
3367 * item0..itemN ... dataN.offset..dataN.size .. data0.size
3369 /* first correct the data pointers */
3370 for (i
= slot
; i
< nritems
; i
++) {
3372 item
= btrfs_item_nr(leaf
, i
);
3374 ioff
= btrfs_item_offset(leaf
, item
);
3375 btrfs_set_item_offset(leaf
, item
, ioff
- data_size
);
3378 /* shift the data */
3379 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
3380 data_end
- data_size
, btrfs_leaf_data(leaf
) +
3381 data_end
, old_data
- data_end
);
3383 data_end
= old_data
;
3384 old_size
= btrfs_item_size_nr(leaf
, slot
);
3385 item
= btrfs_item_nr(leaf
, slot
);
3386 btrfs_set_item_size(leaf
, item
, old_size
+ data_size
);
3387 btrfs_mark_buffer_dirty(leaf
);
3389 if (btrfs_leaf_free_space(root
, leaf
) < 0) {
3390 btrfs_print_leaf(root
, leaf
);
3396 * Given a key and some data, insert items into the tree.
3397 * This does all the path init required, making room in the tree if needed.
3398 * Returns the number of keys that were inserted.
3400 int btrfs_insert_some_items(struct btrfs_trans_handle
*trans
,
3401 struct btrfs_root
*root
,
3402 struct btrfs_path
*path
,
3403 struct btrfs_key
*cpu_key
, u32
*data_size
,
3406 struct extent_buffer
*leaf
;
3407 struct btrfs_item
*item
;
3414 unsigned int data_end
;
3415 struct btrfs_disk_key disk_key
;
3416 struct btrfs_key found_key
;
3418 for (i
= 0; i
< nr
; i
++) {
3419 if (total_size
+ data_size
[i
] + sizeof(struct btrfs_item
) >
3420 BTRFS_LEAF_DATA_SIZE(root
)) {
3424 total_data
+= data_size
[i
];
3425 total_size
+= data_size
[i
] + sizeof(struct btrfs_item
);
3429 ret
= btrfs_search_slot(trans
, root
, cpu_key
, path
, total_size
, 1);
3435 leaf
= path
->nodes
[0];
3437 nritems
= btrfs_header_nritems(leaf
);
3438 data_end
= leaf_data_end(root
, leaf
);
3440 if (btrfs_leaf_free_space(root
, leaf
) < total_size
) {
3441 for (i
= nr
; i
>= 0; i
--) {
3442 total_data
-= data_size
[i
];
3443 total_size
-= data_size
[i
] + sizeof(struct btrfs_item
);
3444 if (total_size
< btrfs_leaf_free_space(root
, leaf
))
3450 slot
= path
->slots
[0];
3453 if (slot
!= nritems
) {
3454 unsigned int old_data
= btrfs_item_end_nr(leaf
, slot
);
3456 item
= btrfs_item_nr(leaf
, slot
);
3457 btrfs_item_key_to_cpu(leaf
, &found_key
, slot
);
3459 /* figure out how many keys we can insert in here */
3460 total_data
= data_size
[0];
3461 for (i
= 1; i
< nr
; i
++) {
3462 if (btrfs_comp_cpu_keys(&found_key
, cpu_key
+ i
) <= 0)
3464 total_data
+= data_size
[i
];
3468 if (old_data
< data_end
) {
3469 btrfs_print_leaf(root
, leaf
);
3470 printk(KERN_CRIT
"slot %d old_data %d data_end %d\n",
3471 slot
, old_data
, data_end
);
3475 * item0..itemN ... dataN.offset..dataN.size .. data0.size
3477 /* first correct the data pointers */
3478 for (i
= slot
; i
< nritems
; i
++) {
3481 item
= btrfs_item_nr(leaf
, i
);
3482 ioff
= btrfs_item_offset(leaf
, item
);
3483 btrfs_set_item_offset(leaf
, item
, ioff
- total_data
);
3485 /* shift the items */
3486 memmove_extent_buffer(leaf
, btrfs_item_nr_offset(slot
+ nr
),
3487 btrfs_item_nr_offset(slot
),
3488 (nritems
- slot
) * sizeof(struct btrfs_item
));
3490 /* shift the data */
3491 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
3492 data_end
- total_data
, btrfs_leaf_data(leaf
) +
3493 data_end
, old_data
- data_end
);
3494 data_end
= old_data
;
3497 * this sucks but it has to be done, if we are inserting at
3498 * the end of the leaf only insert 1 of the items, since we
3499 * have no way of knowing whats on the next leaf and we'd have
3500 * to drop our current locks to figure it out
3505 /* setup the item for the new data */
3506 for (i
= 0; i
< nr
; i
++) {
3507 btrfs_cpu_key_to_disk(&disk_key
, cpu_key
+ i
);
3508 btrfs_set_item_key(leaf
, &disk_key
, slot
+ i
);
3509 item
= btrfs_item_nr(leaf
, slot
+ i
);
3510 btrfs_set_item_offset(leaf
, item
, data_end
- data_size
[i
]);
3511 data_end
-= data_size
[i
];
3512 btrfs_set_item_size(leaf
, item
, data_size
[i
]);
3514 btrfs_set_header_nritems(leaf
, nritems
+ nr
);
3515 btrfs_mark_buffer_dirty(leaf
);
3519 btrfs_cpu_key_to_disk(&disk_key
, cpu_key
);
3520 fixup_low_keys(trans
, root
, path
, &disk_key
, 1);
3523 if (btrfs_leaf_free_space(root
, leaf
) < 0) {
3524 btrfs_print_leaf(root
, leaf
);
3534 * this is a helper for btrfs_insert_empty_items, the main goal here is
3535 * to save stack depth by doing the bulk of the work in a function
3536 * that doesn't call btrfs_search_slot
3538 void setup_items_for_insert(struct btrfs_trans_handle
*trans
,
3539 struct btrfs_root
*root
, struct btrfs_path
*path
,
3540 struct btrfs_key
*cpu_key
, u32
*data_size
,
3541 u32 total_data
, u32 total_size
, int nr
)
3543 struct btrfs_item
*item
;
3546 unsigned int data_end
;
3547 struct btrfs_disk_key disk_key
;
3548 struct extent_buffer
*leaf
;
3551 leaf
= path
->nodes
[0];
3552 slot
= path
->slots
[0];
3554 nritems
= btrfs_header_nritems(leaf
);
3555 data_end
= leaf_data_end(root
, leaf
);
3557 if (btrfs_leaf_free_space(root
, leaf
) < total_size
) {
3558 btrfs_print_leaf(root
, leaf
);
3559 printk(KERN_CRIT
"not enough freespace need %u have %d\n",
3560 total_size
, btrfs_leaf_free_space(root
, leaf
));
3564 if (slot
!= nritems
) {
3565 unsigned int old_data
= btrfs_item_end_nr(leaf
, slot
);
3567 if (old_data
< data_end
) {
3568 btrfs_print_leaf(root
, leaf
);
3569 printk(KERN_CRIT
"slot %d old_data %d data_end %d\n",
3570 slot
, old_data
, data_end
);
3574 * item0..itemN ... dataN.offset..dataN.size .. data0.size
3576 /* first correct the data pointers */
3577 for (i
= slot
; i
< nritems
; i
++) {
3580 item
= btrfs_item_nr(leaf
, i
);
3581 ioff
= btrfs_item_offset(leaf
, item
);
3582 btrfs_set_item_offset(leaf
, item
, ioff
- total_data
);
3584 /* shift the items */
3585 memmove_extent_buffer(leaf
, btrfs_item_nr_offset(slot
+ nr
),
3586 btrfs_item_nr_offset(slot
),
3587 (nritems
- slot
) * sizeof(struct btrfs_item
));
3589 /* shift the data */
3590 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
3591 data_end
- total_data
, btrfs_leaf_data(leaf
) +
3592 data_end
, old_data
- data_end
);
3593 data_end
= old_data
;
3596 /* setup the item for the new data */
3597 for (i
= 0; i
< nr
; i
++) {
3598 btrfs_cpu_key_to_disk(&disk_key
, cpu_key
+ i
);
3599 btrfs_set_item_key(leaf
, &disk_key
, slot
+ i
);
3600 item
= btrfs_item_nr(leaf
, slot
+ i
);
3601 btrfs_set_item_offset(leaf
, item
, data_end
- data_size
[i
]);
3602 data_end
-= data_size
[i
];
3603 btrfs_set_item_size(leaf
, item
, data_size
[i
]);
3606 btrfs_set_header_nritems(leaf
, nritems
+ nr
);
3609 btrfs_cpu_key_to_disk(&disk_key
, cpu_key
);
3610 fixup_low_keys(trans
, root
, path
, &disk_key
, 1);
3612 btrfs_unlock_up_safe(path
, 1);
3613 btrfs_mark_buffer_dirty(leaf
);
3615 if (btrfs_leaf_free_space(root
, leaf
) < 0) {
3616 btrfs_print_leaf(root
, leaf
);
3622 * Given a key and some data, insert items into the tree.
3623 * This does all the path init required, making room in the tree if needed.
3625 int btrfs_insert_empty_items(struct btrfs_trans_handle
*trans
,
3626 struct btrfs_root
*root
,
3627 struct btrfs_path
*path
,
3628 struct btrfs_key
*cpu_key
, u32
*data_size
,
3637 for (i
= 0; i
< nr
; i
++)
3638 total_data
+= data_size
[i
];
3640 total_size
= total_data
+ (nr
* sizeof(struct btrfs_item
));
3641 ret
= btrfs_search_slot(trans
, root
, cpu_key
, path
, total_size
, 1);
3647 slot
= path
->slots
[0];
3650 setup_items_for_insert(trans
, root
, path
, cpu_key
, data_size
,
3651 total_data
, total_size
, nr
);
3656 * Given a key and some data, insert an item into the tree.
3657 * This does all the path init required, making room in the tree if needed.
3659 int btrfs_insert_item(struct btrfs_trans_handle
*trans
, struct btrfs_root
3660 *root
, struct btrfs_key
*cpu_key
, void *data
, u32
3664 struct btrfs_path
*path
;
3665 struct extent_buffer
*leaf
;
3668 path
= btrfs_alloc_path();
3671 ret
= btrfs_insert_empty_item(trans
, root
, path
, cpu_key
, data_size
);
3673 leaf
= path
->nodes
[0];
3674 ptr
= btrfs_item_ptr_offset(leaf
, path
->slots
[0]);
3675 write_extent_buffer(leaf
, data
, ptr
, data_size
);
3676 btrfs_mark_buffer_dirty(leaf
);
3678 btrfs_free_path(path
);
3683 * delete the pointer from a given node.
3685 * the tree should have been previously balanced so the deletion does not
3688 static void del_ptr(struct btrfs_trans_handle
*trans
, struct btrfs_root
*root
,
3689 struct btrfs_path
*path
, int level
, int slot
)
3691 struct extent_buffer
*parent
= path
->nodes
[level
];
3694 nritems
= btrfs_header_nritems(parent
);
3695 if (slot
!= nritems
- 1) {
3696 memmove_extent_buffer(parent
,
3697 btrfs_node_key_ptr_offset(slot
),
3698 btrfs_node_key_ptr_offset(slot
+ 1),
3699 sizeof(struct btrfs_key_ptr
) *
3700 (nritems
- slot
- 1));
3703 btrfs_set_header_nritems(parent
, nritems
);
3704 if (nritems
== 0 && parent
== root
->node
) {
3705 BUG_ON(btrfs_header_level(root
->node
) != 1);
3706 /* just turn the root into a leaf and break */
3707 btrfs_set_header_level(root
->node
, 0);
3708 } else if (slot
== 0) {
3709 struct btrfs_disk_key disk_key
;
3711 btrfs_node_key(parent
, &disk_key
, 0);
3712 fixup_low_keys(trans
, root
, path
, &disk_key
, level
+ 1);
3714 btrfs_mark_buffer_dirty(parent
);
3718 * a helper function to delete the leaf pointed to by path->slots[1] and
3721 * This deletes the pointer in path->nodes[1] and frees the leaf
3722 * block extent. zero is returned if it all worked out, < 0 otherwise.
3724 * The path must have already been setup for deleting the leaf, including
3725 * all the proper balancing. path->nodes[1] must be locked.
3727 static noinline
void btrfs_del_leaf(struct btrfs_trans_handle
*trans
,
3728 struct btrfs_root
*root
,
3729 struct btrfs_path
*path
,
3730 struct extent_buffer
*leaf
)
3732 WARN_ON(btrfs_header_generation(leaf
) != trans
->transid
);
3733 del_ptr(trans
, root
, path
, 1, path
->slots
[1]);
3736 * btrfs_free_extent is expensive, we want to make sure we
3737 * aren't holding any locks when we call it
3739 btrfs_unlock_up_safe(path
, 0);
3741 root_sub_used(root
, leaf
->len
);
3743 btrfs_free_tree_block(trans
, root
, leaf
, 0, 1, 0);
3746 * delete the item at the leaf level in path. If that empties
3747 * the leaf, remove it from the tree
3749 int btrfs_del_items(struct btrfs_trans_handle
*trans
, struct btrfs_root
*root
,
3750 struct btrfs_path
*path
, int slot
, int nr
)
3752 struct extent_buffer
*leaf
;
3753 struct btrfs_item
*item
;
3761 leaf
= path
->nodes
[0];
3762 last_off
= btrfs_item_offset_nr(leaf
, slot
+ nr
- 1);
3764 for (i
= 0; i
< nr
; i
++)
3765 dsize
+= btrfs_item_size_nr(leaf
, slot
+ i
);
3767 nritems
= btrfs_header_nritems(leaf
);
3769 if (slot
+ nr
!= nritems
) {
3770 int data_end
= leaf_data_end(root
, leaf
);
3772 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
3774 btrfs_leaf_data(leaf
) + data_end
,
3775 last_off
- data_end
);
3777 for (i
= slot
+ nr
; i
< nritems
; i
++) {
3780 item
= btrfs_item_nr(leaf
, i
);
3781 ioff
= btrfs_item_offset(leaf
, item
);
3782 btrfs_set_item_offset(leaf
, item
, ioff
+ dsize
);
3785 memmove_extent_buffer(leaf
, btrfs_item_nr_offset(slot
),
3786 btrfs_item_nr_offset(slot
+ nr
),
3787 sizeof(struct btrfs_item
) *
3788 (nritems
- slot
- nr
));
3790 btrfs_set_header_nritems(leaf
, nritems
- nr
);
3793 /* delete the leaf if we've emptied it */
3795 if (leaf
== root
->node
) {
3796 btrfs_set_header_level(leaf
, 0);
3798 btrfs_set_path_blocking(path
);
3799 clean_tree_block(trans
, root
, leaf
);
3800 btrfs_del_leaf(trans
, root
, path
, leaf
);
3803 int used
= leaf_space_used(leaf
, 0, nritems
);
3805 struct btrfs_disk_key disk_key
;
3807 btrfs_item_key(leaf
, &disk_key
, 0);
3808 fixup_low_keys(trans
, root
, path
, &disk_key
, 1);
3811 /* delete the leaf if it is mostly empty */
3812 if (used
< BTRFS_LEAF_DATA_SIZE(root
) / 3) {
3813 /* push_leaf_left fixes the path.
3814 * make sure the path still points to our leaf
3815 * for possible call to del_ptr below
3817 slot
= path
->slots
[1];
3818 extent_buffer_get(leaf
);
3820 btrfs_set_path_blocking(path
);
3821 wret
= push_leaf_left(trans
, root
, path
, 1, 1,
3823 if (wret
< 0 && wret
!= -ENOSPC
)
3826 if (path
->nodes
[0] == leaf
&&
3827 btrfs_header_nritems(leaf
)) {
3828 wret
= push_leaf_right(trans
, root
, path
, 1,
3830 if (wret
< 0 && wret
!= -ENOSPC
)
3834 if (btrfs_header_nritems(leaf
) == 0) {
3835 path
->slots
[1] = slot
;
3836 btrfs_del_leaf(trans
, root
, path
, leaf
);
3837 free_extent_buffer(leaf
);
3840 /* if we're still in the path, make sure
3841 * we're dirty. Otherwise, one of the
3842 * push_leaf functions must have already
3843 * dirtied this buffer
3845 if (path
->nodes
[0] == leaf
)
3846 btrfs_mark_buffer_dirty(leaf
);
3847 free_extent_buffer(leaf
);
3850 btrfs_mark_buffer_dirty(leaf
);
3857 * search the tree again to find a leaf with lesser keys
3858 * returns 0 if it found something or 1 if there are no lesser leaves.
3859 * returns < 0 on io errors.
3861 * This may release the path, and so you may lose any locks held at the
3864 int btrfs_prev_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
)
3866 struct btrfs_key key
;
3867 struct btrfs_disk_key found_key
;
3870 btrfs_item_key_to_cpu(path
->nodes
[0], &key
, 0);
3874 else if (key
.type
> 0)
3876 else if (key
.objectid
> 0)
3881 btrfs_release_path(path
);
3882 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
3885 btrfs_item_key(path
->nodes
[0], &found_key
, 0);
3886 ret
= comp_keys(&found_key
, &key
);
3893 * A helper function to walk down the tree starting at min_key, and looking
3894 * for nodes or leaves that are either in cache or have a minimum
3895 * transaction id. This is used by the btree defrag code, and tree logging
3897 * This does not cow, but it does stuff the starting key it finds back
3898 * into min_key, so you can call btrfs_search_slot with cow=1 on the
3899 * key and get a writable path.
3901 * This does lock as it descends, and path->keep_locks should be set
3902 * to 1 by the caller.
3904 * This honors path->lowest_level to prevent descent past a given level
3907 * min_trans indicates the oldest transaction that you are interested
3908 * in walking through. Any nodes or leaves older than min_trans are
3909 * skipped over (without reading them).
3911 * returns zero if something useful was found, < 0 on error and 1 if there
3912 * was nothing in the tree that matched the search criteria.
3914 int btrfs_search_forward(struct btrfs_root
*root
, struct btrfs_key
*min_key
,
3915 struct btrfs_key
*max_key
,
3916 struct btrfs_path
*path
, int cache_only
,
3919 struct extent_buffer
*cur
;
3920 struct btrfs_key found_key
;
3927 WARN_ON(!path
->keep_locks
);
3929 cur
= btrfs_read_lock_root_node(root
);
3930 level
= btrfs_header_level(cur
);
3931 WARN_ON(path
->nodes
[level
]);
3932 path
->nodes
[level
] = cur
;
3933 path
->locks
[level
] = BTRFS_READ_LOCK
;
3935 if (btrfs_header_generation(cur
) < min_trans
) {
3940 nritems
= btrfs_header_nritems(cur
);
3941 level
= btrfs_header_level(cur
);
3942 sret
= bin_search(cur
, min_key
, level
, &slot
);
3944 /* at the lowest level, we're done, setup the path and exit */
3945 if (level
== path
->lowest_level
) {
3946 if (slot
>= nritems
)
3949 path
->slots
[level
] = slot
;
3950 btrfs_item_key_to_cpu(cur
, &found_key
, slot
);
3953 if (sret
&& slot
> 0)
3956 * check this node pointer against the cache_only and
3957 * min_trans parameters. If it isn't in cache or is too
3958 * old, skip to the next one.
3960 while (slot
< nritems
) {
3963 struct extent_buffer
*tmp
;
3964 struct btrfs_disk_key disk_key
;
3966 blockptr
= btrfs_node_blockptr(cur
, slot
);
3967 gen
= btrfs_node_ptr_generation(cur
, slot
);
3968 if (gen
< min_trans
) {
3976 btrfs_node_key(cur
, &disk_key
, slot
);
3977 if (comp_keys(&disk_key
, max_key
) >= 0) {
3983 tmp
= btrfs_find_tree_block(root
, blockptr
,
3984 btrfs_level_size(root
, level
- 1));
3986 if (tmp
&& btrfs_buffer_uptodate(tmp
, gen
)) {
3987 free_extent_buffer(tmp
);
3991 free_extent_buffer(tmp
);
3996 * we didn't find a candidate key in this node, walk forward
3997 * and find another one
3999 if (slot
>= nritems
) {
4000 path
->slots
[level
] = slot
;
4001 btrfs_set_path_blocking(path
);
4002 sret
= btrfs_find_next_key(root
, path
, min_key
, level
,
4003 cache_only
, min_trans
);
4005 btrfs_release_path(path
);
4011 /* save our key for returning back */
4012 btrfs_node_key_to_cpu(cur
, &found_key
, slot
);
4013 path
->slots
[level
] = slot
;
4014 if (level
== path
->lowest_level
) {
4016 unlock_up(path
, level
, 1);
4019 btrfs_set_path_blocking(path
);
4020 cur
= read_node_slot(root
, cur
, slot
);
4021 BUG_ON(!cur
); /* -ENOMEM */
4023 btrfs_tree_read_lock(cur
);
4025 path
->locks
[level
- 1] = BTRFS_READ_LOCK
;
4026 path
->nodes
[level
- 1] = cur
;
4027 unlock_up(path
, level
, 1);
4028 btrfs_clear_path_blocking(path
, NULL
, 0);
4032 memcpy(min_key
, &found_key
, sizeof(found_key
));
4033 btrfs_set_path_blocking(path
);
4038 * this is similar to btrfs_next_leaf, but does not try to preserve
4039 * and fixup the path. It looks for and returns the next key in the
4040 * tree based on the current path and the cache_only and min_trans
4043 * 0 is returned if another key is found, < 0 if there are any errors
4044 * and 1 is returned if there are no higher keys in the tree
4046 * path->keep_locks should be set to 1 on the search made before
4047 * calling this function.
4049 int btrfs_find_next_key(struct btrfs_root
*root
, struct btrfs_path
*path
,
4050 struct btrfs_key
*key
, int level
,
4051 int cache_only
, u64 min_trans
)
4054 struct extent_buffer
*c
;
4056 WARN_ON(!path
->keep_locks
);
4057 while (level
< BTRFS_MAX_LEVEL
) {
4058 if (!path
->nodes
[level
])
4061 slot
= path
->slots
[level
] + 1;
4062 c
= path
->nodes
[level
];
4064 if (slot
>= btrfs_header_nritems(c
)) {
4067 struct btrfs_key cur_key
;
4068 if (level
+ 1 >= BTRFS_MAX_LEVEL
||
4069 !path
->nodes
[level
+ 1])
4072 if (path
->locks
[level
+ 1]) {
4077 slot
= btrfs_header_nritems(c
) - 1;
4079 btrfs_item_key_to_cpu(c
, &cur_key
, slot
);
4081 btrfs_node_key_to_cpu(c
, &cur_key
, slot
);
4083 orig_lowest
= path
->lowest_level
;
4084 btrfs_release_path(path
);
4085 path
->lowest_level
= level
;
4086 ret
= btrfs_search_slot(NULL
, root
, &cur_key
, path
,
4088 path
->lowest_level
= orig_lowest
;
4092 c
= path
->nodes
[level
];
4093 slot
= path
->slots
[level
];
4100 btrfs_item_key_to_cpu(c
, key
, slot
);
4102 u64 blockptr
= btrfs_node_blockptr(c
, slot
);
4103 u64 gen
= btrfs_node_ptr_generation(c
, slot
);
4106 struct extent_buffer
*cur
;
4107 cur
= btrfs_find_tree_block(root
, blockptr
,
4108 btrfs_level_size(root
, level
- 1));
4109 if (!cur
|| !btrfs_buffer_uptodate(cur
, gen
)) {
4112 free_extent_buffer(cur
);
4115 free_extent_buffer(cur
);
4117 if (gen
< min_trans
) {
4121 btrfs_node_key_to_cpu(c
, key
, slot
);
4129 * search the tree again to find a leaf with greater keys
4130 * returns 0 if it found something or 1 if there are no greater leaves.
4131 * returns < 0 on io errors.
4133 int btrfs_next_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
)
4137 struct extent_buffer
*c
;
4138 struct extent_buffer
*next
;
4139 struct btrfs_key key
;
4142 int old_spinning
= path
->leave_spinning
;
4143 int next_rw_lock
= 0;
4145 nritems
= btrfs_header_nritems(path
->nodes
[0]);
4149 btrfs_item_key_to_cpu(path
->nodes
[0], &key
, nritems
- 1);
4154 btrfs_release_path(path
);
4156 path
->keep_locks
= 1;
4157 path
->leave_spinning
= 1;
4159 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
4160 path
->keep_locks
= 0;
4165 nritems
= btrfs_header_nritems(path
->nodes
[0]);
4167 * by releasing the path above we dropped all our locks. A balance
4168 * could have added more items next to the key that used to be
4169 * at the very end of the block. So, check again here and
4170 * advance the path if there are now more items available.
4172 if (nritems
> 0 && path
->slots
[0] < nritems
- 1) {
4179 while (level
< BTRFS_MAX_LEVEL
) {
4180 if (!path
->nodes
[level
]) {
4185 slot
= path
->slots
[level
] + 1;
4186 c
= path
->nodes
[level
];
4187 if (slot
>= btrfs_header_nritems(c
)) {
4189 if (level
== BTRFS_MAX_LEVEL
) {
4197 btrfs_tree_unlock_rw(next
, next_rw_lock
);
4198 free_extent_buffer(next
);
4202 next_rw_lock
= path
->locks
[level
];
4203 ret
= read_block_for_search(NULL
, root
, path
, &next
, level
,
4209 btrfs_release_path(path
);
4213 if (!path
->skip_locking
) {
4214 ret
= btrfs_try_tree_read_lock(next
);
4216 btrfs_set_path_blocking(path
);
4217 btrfs_tree_read_lock(next
);
4218 btrfs_clear_path_blocking(path
, next
,
4221 next_rw_lock
= BTRFS_READ_LOCK
;
4225 path
->slots
[level
] = slot
;
4228 c
= path
->nodes
[level
];
4229 if (path
->locks
[level
])
4230 btrfs_tree_unlock_rw(c
, path
->locks
[level
]);
4232 free_extent_buffer(c
);
4233 path
->nodes
[level
] = next
;
4234 path
->slots
[level
] = 0;
4235 if (!path
->skip_locking
)
4236 path
->locks
[level
] = next_rw_lock
;
4240 ret
= read_block_for_search(NULL
, root
, path
, &next
, level
,
4246 btrfs_release_path(path
);
4250 if (!path
->skip_locking
) {
4251 ret
= btrfs_try_tree_read_lock(next
);
4253 btrfs_set_path_blocking(path
);
4254 btrfs_tree_read_lock(next
);
4255 btrfs_clear_path_blocking(path
, next
,
4258 next_rw_lock
= BTRFS_READ_LOCK
;
4263 unlock_up(path
, 0, 1);
4264 path
->leave_spinning
= old_spinning
;
4266 btrfs_set_path_blocking(path
);
4272 * this uses btrfs_prev_leaf to walk backwards in the tree, and keeps
4273 * searching until it gets past min_objectid or finds an item of 'type'
4275 * returns 0 if something is found, 1 if nothing was found and < 0 on error
4277 int btrfs_previous_item(struct btrfs_root
*root
,
4278 struct btrfs_path
*path
, u64 min_objectid
,
4281 struct btrfs_key found_key
;
4282 struct extent_buffer
*leaf
;
4287 if (path
->slots
[0] == 0) {
4288 btrfs_set_path_blocking(path
);
4289 ret
= btrfs_prev_leaf(root
, path
);
4295 leaf
= path
->nodes
[0];
4296 nritems
= btrfs_header_nritems(leaf
);
4299 if (path
->slots
[0] == nritems
)
4302 btrfs_item_key_to_cpu(leaf
, &found_key
, path
->slots
[0]);
4303 if (found_key
.objectid
< min_objectid
)
4305 if (found_key
.type
== type
)
4307 if (found_key
.objectid
== min_objectid
&&
4308 found_key
.type
< type
)