2 * Copyright (C) 2007,2008 Oracle. All rights reserved.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
19 #include <linux/sched.h>
20 #include <linux/slab.h>
21 #include <linux/rbtree.h>
24 #include "transaction.h"
25 #include "print-tree.h"
28 static int split_node(struct btrfs_trans_handle
*trans
, struct btrfs_root
29 *root
, struct btrfs_path
*path
, int level
);
30 static int split_leaf(struct btrfs_trans_handle
*trans
, struct btrfs_root
31 *root
, struct btrfs_key
*ins_key
,
32 struct btrfs_path
*path
, int data_size
, int extend
);
33 static int push_node_left(struct btrfs_trans_handle
*trans
,
34 struct btrfs_root
*root
, struct extent_buffer
*dst
,
35 struct extent_buffer
*src
, int empty
);
36 static int balance_node_right(struct btrfs_trans_handle
*trans
,
37 struct btrfs_root
*root
,
38 struct extent_buffer
*dst_buf
,
39 struct extent_buffer
*src_buf
);
40 static void del_ptr(struct btrfs_root
*root
, struct btrfs_path
*path
,
42 static int tree_mod_log_free_eb(struct btrfs_fs_info
*fs_info
,
43 struct extent_buffer
*eb
);
45 struct btrfs_path
*btrfs_alloc_path(void)
47 struct btrfs_path
*path
;
48 path
= kmem_cache_zalloc(btrfs_path_cachep
, GFP_NOFS
);
53 * set all locked nodes in the path to blocking locks. This should
54 * be done before scheduling
56 noinline
void btrfs_set_path_blocking(struct btrfs_path
*p
)
59 for (i
= 0; i
< BTRFS_MAX_LEVEL
; i
++) {
60 if (!p
->nodes
[i
] || !p
->locks
[i
])
62 btrfs_set_lock_blocking_rw(p
->nodes
[i
], p
->locks
[i
]);
63 if (p
->locks
[i
] == BTRFS_READ_LOCK
)
64 p
->locks
[i
] = BTRFS_READ_LOCK_BLOCKING
;
65 else if (p
->locks
[i
] == BTRFS_WRITE_LOCK
)
66 p
->locks
[i
] = BTRFS_WRITE_LOCK_BLOCKING
;
71 * reset all the locked nodes in the patch to spinning locks.
73 * held is used to keep lockdep happy, when lockdep is enabled
74 * we set held to a blocking lock before we go around and
75 * retake all the spinlocks in the path. You can safely use NULL
78 noinline
void btrfs_clear_path_blocking(struct btrfs_path
*p
,
79 struct extent_buffer
*held
, int held_rw
)
83 #ifdef CONFIG_DEBUG_LOCK_ALLOC
84 /* lockdep really cares that we take all of these spinlocks
85 * in the right order. If any of the locks in the path are not
86 * currently blocking, it is going to complain. So, make really
87 * really sure by forcing the path to blocking before we clear
91 btrfs_set_lock_blocking_rw(held
, held_rw
);
92 if (held_rw
== BTRFS_WRITE_LOCK
)
93 held_rw
= BTRFS_WRITE_LOCK_BLOCKING
;
94 else if (held_rw
== BTRFS_READ_LOCK
)
95 held_rw
= BTRFS_READ_LOCK_BLOCKING
;
97 btrfs_set_path_blocking(p
);
100 for (i
= BTRFS_MAX_LEVEL
- 1; i
>= 0; i
--) {
101 if (p
->nodes
[i
] && p
->locks
[i
]) {
102 btrfs_clear_lock_blocking_rw(p
->nodes
[i
], p
->locks
[i
]);
103 if (p
->locks
[i
] == BTRFS_WRITE_LOCK_BLOCKING
)
104 p
->locks
[i
] = BTRFS_WRITE_LOCK
;
105 else if (p
->locks
[i
] == BTRFS_READ_LOCK_BLOCKING
)
106 p
->locks
[i
] = BTRFS_READ_LOCK
;
110 #ifdef CONFIG_DEBUG_LOCK_ALLOC
112 btrfs_clear_lock_blocking_rw(held
, held_rw
);
116 /* this also releases the path */
117 void btrfs_free_path(struct btrfs_path
*p
)
121 btrfs_release_path(p
);
122 kmem_cache_free(btrfs_path_cachep
, p
);
126 * path release drops references on the extent buffers in the path
127 * and it drops any locks held by this path
129 * It is safe to call this on paths that no locks or extent buffers held.
131 noinline
void btrfs_release_path(struct btrfs_path
*p
)
135 for (i
= 0; i
< BTRFS_MAX_LEVEL
; i
++) {
140 btrfs_tree_unlock_rw(p
->nodes
[i
], p
->locks
[i
]);
143 free_extent_buffer(p
->nodes
[i
]);
149 * safely gets a reference on the root node of a tree. A lock
150 * is not taken, so a concurrent writer may put a different node
151 * at the root of the tree. See btrfs_lock_root_node for the
154 * The extent buffer returned by this has a reference taken, so
155 * it won't disappear. It may stop being the root of the tree
156 * at any time because there are no locks held.
158 struct extent_buffer
*btrfs_root_node(struct btrfs_root
*root
)
160 struct extent_buffer
*eb
;
164 eb
= rcu_dereference(root
->node
);
167 * RCU really hurts here, we could free up the root node because
168 * it was cow'ed but we may not get the new root node yet so do
169 * the inc_not_zero dance and if it doesn't work then
170 * synchronize_rcu and try again.
172 if (atomic_inc_not_zero(&eb
->refs
)) {
182 /* loop around taking references on and locking the root node of the
183 * tree until you end up with a lock on the root. A locked buffer
184 * is returned, with a reference held.
186 struct extent_buffer
*btrfs_lock_root_node(struct btrfs_root
*root
)
188 struct extent_buffer
*eb
;
191 eb
= btrfs_root_node(root
);
193 if (eb
== root
->node
)
195 btrfs_tree_unlock(eb
);
196 free_extent_buffer(eb
);
201 /* loop around taking references on and locking the root node of the
202 * tree until you end up with a lock on the root. A locked buffer
203 * is returned, with a reference held.
205 static struct extent_buffer
*btrfs_read_lock_root_node(struct btrfs_root
*root
)
207 struct extent_buffer
*eb
;
210 eb
= btrfs_root_node(root
);
211 btrfs_tree_read_lock(eb
);
212 if (eb
== root
->node
)
214 btrfs_tree_read_unlock(eb
);
215 free_extent_buffer(eb
);
220 /* cowonly root (everything not a reference counted cow subvolume), just get
221 * put onto a simple dirty list. transaction.c walks this to make sure they
222 * get properly updated on disk.
224 static void add_root_to_dirty_list(struct btrfs_root
*root
)
226 spin_lock(&root
->fs_info
->trans_lock
);
227 if (test_bit(BTRFS_ROOT_TRACK_DIRTY
, &root
->state
) &&
228 list_empty(&root
->dirty_list
)) {
229 list_add(&root
->dirty_list
,
230 &root
->fs_info
->dirty_cowonly_roots
);
232 spin_unlock(&root
->fs_info
->trans_lock
);
236 * used by snapshot creation to make a copy of a root for a tree with
237 * a given objectid. The buffer with the new root node is returned in
238 * cow_ret, and this func returns zero on success or a negative error code.
240 int btrfs_copy_root(struct btrfs_trans_handle
*trans
,
241 struct btrfs_root
*root
,
242 struct extent_buffer
*buf
,
243 struct extent_buffer
**cow_ret
, u64 new_root_objectid
)
245 struct extent_buffer
*cow
;
248 struct btrfs_disk_key disk_key
;
250 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
251 trans
->transid
!= root
->fs_info
->running_transaction
->transid
);
252 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
253 trans
->transid
!= root
->last_trans
);
255 level
= btrfs_header_level(buf
);
257 btrfs_item_key(buf
, &disk_key
, 0);
259 btrfs_node_key(buf
, &disk_key
, 0);
261 cow
= btrfs_alloc_free_block(trans
, root
, buf
->len
, 0,
262 new_root_objectid
, &disk_key
, level
,
267 copy_extent_buffer(cow
, buf
, 0, 0, cow
->len
);
268 btrfs_set_header_bytenr(cow
, cow
->start
);
269 btrfs_set_header_generation(cow
, trans
->transid
);
270 btrfs_set_header_backref_rev(cow
, BTRFS_MIXED_BACKREF_REV
);
271 btrfs_clear_header_flag(cow
, BTRFS_HEADER_FLAG_WRITTEN
|
272 BTRFS_HEADER_FLAG_RELOC
);
273 if (new_root_objectid
== BTRFS_TREE_RELOC_OBJECTID
)
274 btrfs_set_header_flag(cow
, BTRFS_HEADER_FLAG_RELOC
);
276 btrfs_set_header_owner(cow
, new_root_objectid
);
278 write_extent_buffer(cow
, root
->fs_info
->fsid
, btrfs_header_fsid(),
281 WARN_ON(btrfs_header_generation(buf
) > trans
->transid
);
282 if (new_root_objectid
== BTRFS_TREE_RELOC_OBJECTID
)
283 ret
= btrfs_inc_ref(trans
, root
, cow
, 1, 1);
285 ret
= btrfs_inc_ref(trans
, root
, cow
, 0, 1);
290 btrfs_mark_buffer_dirty(cow
);
299 MOD_LOG_KEY_REMOVE_WHILE_FREEING
,
300 MOD_LOG_KEY_REMOVE_WHILE_MOVING
,
302 MOD_LOG_ROOT_REPLACE
,
305 struct tree_mod_move
{
310 struct tree_mod_root
{
315 struct tree_mod_elem
{
317 u64 index
; /* shifted logical */
321 /* this is used for MOD_LOG_KEY_* and MOD_LOG_MOVE_KEYS operations */
324 /* this is used for MOD_LOG_KEY* and MOD_LOG_ROOT_REPLACE */
327 /* those are used for op == MOD_LOG_KEY_{REPLACE,REMOVE} */
328 struct btrfs_disk_key key
;
331 /* this is used for op == MOD_LOG_MOVE_KEYS */
332 struct tree_mod_move move
;
334 /* this is used for op == MOD_LOG_ROOT_REPLACE */
335 struct tree_mod_root old_root
;
338 static inline void tree_mod_log_read_lock(struct btrfs_fs_info
*fs_info
)
340 read_lock(&fs_info
->tree_mod_log_lock
);
343 static inline void tree_mod_log_read_unlock(struct btrfs_fs_info
*fs_info
)
345 read_unlock(&fs_info
->tree_mod_log_lock
);
348 static inline void tree_mod_log_write_lock(struct btrfs_fs_info
*fs_info
)
350 write_lock(&fs_info
->tree_mod_log_lock
);
353 static inline void tree_mod_log_write_unlock(struct btrfs_fs_info
*fs_info
)
355 write_unlock(&fs_info
->tree_mod_log_lock
);
359 * Increment the upper half of tree_mod_seq, set lower half zero.
361 * Must be called with fs_info->tree_mod_seq_lock held.
363 static inline u64
btrfs_inc_tree_mod_seq_major(struct btrfs_fs_info
*fs_info
)
365 u64 seq
= atomic64_read(&fs_info
->tree_mod_seq
);
366 seq
&= 0xffffffff00000000ull
;
368 atomic64_set(&fs_info
->tree_mod_seq
, seq
);
373 * Increment the lower half of tree_mod_seq.
375 * Must be called with fs_info->tree_mod_seq_lock held. The way major numbers
376 * are generated should not technically require a spin lock here. (Rationale:
377 * incrementing the minor while incrementing the major seq number is between its
378 * atomic64_read and atomic64_set calls doesn't duplicate sequence numbers, it
379 * just returns a unique sequence number as usual.) We have decided to leave
380 * that requirement in here and rethink it once we notice it really imposes a
381 * problem on some workload.
383 static inline u64
btrfs_inc_tree_mod_seq_minor(struct btrfs_fs_info
*fs_info
)
385 return atomic64_inc_return(&fs_info
->tree_mod_seq
);
389 * return the last minor in the previous major tree_mod_seq number
391 u64
btrfs_tree_mod_seq_prev(u64 seq
)
393 return (seq
& 0xffffffff00000000ull
) - 1ull;
397 * This adds a new blocker to the tree mod log's blocker list if the @elem
398 * passed does not already have a sequence number set. So when a caller expects
399 * to record tree modifications, it should ensure to set elem->seq to zero
400 * before calling btrfs_get_tree_mod_seq.
401 * Returns a fresh, unused tree log modification sequence number, even if no new
404 u64
btrfs_get_tree_mod_seq(struct btrfs_fs_info
*fs_info
,
405 struct seq_list
*elem
)
409 tree_mod_log_write_lock(fs_info
);
410 spin_lock(&fs_info
->tree_mod_seq_lock
);
412 elem
->seq
= btrfs_inc_tree_mod_seq_major(fs_info
);
413 list_add_tail(&elem
->list
, &fs_info
->tree_mod_seq_list
);
415 seq
= btrfs_inc_tree_mod_seq_minor(fs_info
);
416 spin_unlock(&fs_info
->tree_mod_seq_lock
);
417 tree_mod_log_write_unlock(fs_info
);
422 void btrfs_put_tree_mod_seq(struct btrfs_fs_info
*fs_info
,
423 struct seq_list
*elem
)
425 struct rb_root
*tm_root
;
426 struct rb_node
*node
;
427 struct rb_node
*next
;
428 struct seq_list
*cur_elem
;
429 struct tree_mod_elem
*tm
;
430 u64 min_seq
= (u64
)-1;
431 u64 seq_putting
= elem
->seq
;
436 spin_lock(&fs_info
->tree_mod_seq_lock
);
437 list_del(&elem
->list
);
440 list_for_each_entry(cur_elem
, &fs_info
->tree_mod_seq_list
, list
) {
441 if (cur_elem
->seq
< min_seq
) {
442 if (seq_putting
> cur_elem
->seq
) {
444 * blocker with lower sequence number exists, we
445 * cannot remove anything from the log
447 spin_unlock(&fs_info
->tree_mod_seq_lock
);
450 min_seq
= cur_elem
->seq
;
453 spin_unlock(&fs_info
->tree_mod_seq_lock
);
456 * anything that's lower than the lowest existing (read: blocked)
457 * sequence number can be removed from the tree.
459 tree_mod_log_write_lock(fs_info
);
460 tm_root
= &fs_info
->tree_mod_log
;
461 for (node
= rb_first(tm_root
); node
; node
= next
) {
462 next
= rb_next(node
);
463 tm
= container_of(node
, struct tree_mod_elem
, node
);
464 if (tm
->seq
> min_seq
)
466 rb_erase(node
, tm_root
);
469 tree_mod_log_write_unlock(fs_info
);
473 * key order of the log:
476 * the index is the shifted logical of the *new* root node for root replace
477 * operations, or the shifted logical of the affected block for all other
480 * Note: must be called with write lock (tree_mod_log_write_lock).
483 __tree_mod_log_insert(struct btrfs_fs_info
*fs_info
, struct tree_mod_elem
*tm
)
485 struct rb_root
*tm_root
;
486 struct rb_node
**new;
487 struct rb_node
*parent
= NULL
;
488 struct tree_mod_elem
*cur
;
492 spin_lock(&fs_info
->tree_mod_seq_lock
);
493 tm
->seq
= btrfs_inc_tree_mod_seq_minor(fs_info
);
494 spin_unlock(&fs_info
->tree_mod_seq_lock
);
496 tm_root
= &fs_info
->tree_mod_log
;
497 new = &tm_root
->rb_node
;
499 cur
= container_of(*new, struct tree_mod_elem
, node
);
501 if (cur
->index
< tm
->index
)
502 new = &((*new)->rb_left
);
503 else if (cur
->index
> tm
->index
)
504 new = &((*new)->rb_right
);
505 else if (cur
->seq
< tm
->seq
)
506 new = &((*new)->rb_left
);
507 else if (cur
->seq
> tm
->seq
)
508 new = &((*new)->rb_right
);
513 rb_link_node(&tm
->node
, parent
, new);
514 rb_insert_color(&tm
->node
, tm_root
);
519 * Determines if logging can be omitted. Returns 1 if it can. Otherwise, it
520 * returns zero with the tree_mod_log_lock acquired. The caller must hold
521 * this until all tree mod log insertions are recorded in the rb tree and then
522 * call tree_mod_log_write_unlock() to release.
524 static inline int tree_mod_dont_log(struct btrfs_fs_info
*fs_info
,
525 struct extent_buffer
*eb
) {
527 if (list_empty(&(fs_info
)->tree_mod_seq_list
))
529 if (eb
&& btrfs_header_level(eb
) == 0)
532 tree_mod_log_write_lock(fs_info
);
533 if (list_empty(&(fs_info
)->tree_mod_seq_list
)) {
534 tree_mod_log_write_unlock(fs_info
);
541 /* Similar to tree_mod_dont_log, but doesn't acquire any locks. */
542 static inline int tree_mod_need_log(const struct btrfs_fs_info
*fs_info
,
543 struct extent_buffer
*eb
)
546 if (list_empty(&(fs_info
)->tree_mod_seq_list
))
548 if (eb
&& btrfs_header_level(eb
) == 0)
554 static struct tree_mod_elem
*
555 alloc_tree_mod_elem(struct extent_buffer
*eb
, int slot
,
556 enum mod_log_op op
, gfp_t flags
)
558 struct tree_mod_elem
*tm
;
560 tm
= kzalloc(sizeof(*tm
), flags
);
564 tm
->index
= eb
->start
>> PAGE_CACHE_SHIFT
;
565 if (op
!= MOD_LOG_KEY_ADD
) {
566 btrfs_node_key(eb
, &tm
->key
, slot
);
567 tm
->blockptr
= btrfs_node_blockptr(eb
, slot
);
571 tm
->generation
= btrfs_node_ptr_generation(eb
, slot
);
572 RB_CLEAR_NODE(&tm
->node
);
578 tree_mod_log_insert_key(struct btrfs_fs_info
*fs_info
,
579 struct extent_buffer
*eb
, int slot
,
580 enum mod_log_op op
, gfp_t flags
)
582 struct tree_mod_elem
*tm
;
585 if (!tree_mod_need_log(fs_info
, eb
))
588 tm
= alloc_tree_mod_elem(eb
, slot
, op
, flags
);
592 if (tree_mod_dont_log(fs_info
, eb
)) {
597 ret
= __tree_mod_log_insert(fs_info
, tm
);
598 tree_mod_log_write_unlock(fs_info
);
606 tree_mod_log_insert_move(struct btrfs_fs_info
*fs_info
,
607 struct extent_buffer
*eb
, int dst_slot
, int src_slot
,
608 int nr_items
, gfp_t flags
)
610 struct tree_mod_elem
*tm
= NULL
;
611 struct tree_mod_elem
**tm_list
= NULL
;
616 if (!tree_mod_need_log(fs_info
, eb
))
619 tm_list
= kzalloc(nr_items
* sizeof(struct tree_mod_elem
*), flags
);
623 tm
= kzalloc(sizeof(*tm
), flags
);
629 tm
->index
= eb
->start
>> PAGE_CACHE_SHIFT
;
631 tm
->move
.dst_slot
= dst_slot
;
632 tm
->move
.nr_items
= nr_items
;
633 tm
->op
= MOD_LOG_MOVE_KEYS
;
635 for (i
= 0; i
+ dst_slot
< src_slot
&& i
< nr_items
; i
++) {
636 tm_list
[i
] = alloc_tree_mod_elem(eb
, i
+ dst_slot
,
637 MOD_LOG_KEY_REMOVE_WHILE_MOVING
, flags
);
644 if (tree_mod_dont_log(fs_info
, eb
))
649 * When we override something during the move, we log these removals.
650 * This can only happen when we move towards the beginning of the
651 * buffer, i.e. dst_slot < src_slot.
653 for (i
= 0; i
+ dst_slot
< src_slot
&& i
< nr_items
; i
++) {
654 ret
= __tree_mod_log_insert(fs_info
, tm_list
[i
]);
659 ret
= __tree_mod_log_insert(fs_info
, tm
);
662 tree_mod_log_write_unlock(fs_info
);
667 for (i
= 0; i
< nr_items
; i
++) {
668 if (tm_list
[i
] && !RB_EMPTY_NODE(&tm_list
[i
]->node
))
669 rb_erase(&tm_list
[i
]->node
, &fs_info
->tree_mod_log
);
673 tree_mod_log_write_unlock(fs_info
);
681 __tree_mod_log_free_eb(struct btrfs_fs_info
*fs_info
,
682 struct tree_mod_elem
**tm_list
,
688 for (i
= nritems
- 1; i
>= 0; i
--) {
689 ret
= __tree_mod_log_insert(fs_info
, tm_list
[i
]);
691 for (j
= nritems
- 1; j
> i
; j
--)
692 rb_erase(&tm_list
[j
]->node
,
693 &fs_info
->tree_mod_log
);
702 tree_mod_log_insert_root(struct btrfs_fs_info
*fs_info
,
703 struct extent_buffer
*old_root
,
704 struct extent_buffer
*new_root
, gfp_t flags
,
707 struct tree_mod_elem
*tm
= NULL
;
708 struct tree_mod_elem
**tm_list
= NULL
;
713 if (!tree_mod_need_log(fs_info
, NULL
))
716 if (log_removal
&& btrfs_header_level(old_root
) > 0) {
717 nritems
= btrfs_header_nritems(old_root
);
718 tm_list
= kzalloc(nritems
* sizeof(struct tree_mod_elem
*),
724 for (i
= 0; i
< nritems
; i
++) {
725 tm_list
[i
] = alloc_tree_mod_elem(old_root
, i
,
726 MOD_LOG_KEY_REMOVE_WHILE_FREEING
, flags
);
734 tm
= kzalloc(sizeof(*tm
), flags
);
740 tm
->index
= new_root
->start
>> PAGE_CACHE_SHIFT
;
741 tm
->old_root
.logical
= old_root
->start
;
742 tm
->old_root
.level
= btrfs_header_level(old_root
);
743 tm
->generation
= btrfs_header_generation(old_root
);
744 tm
->op
= MOD_LOG_ROOT_REPLACE
;
746 if (tree_mod_dont_log(fs_info
, NULL
))
750 ret
= __tree_mod_log_free_eb(fs_info
, tm_list
, nritems
);
752 ret
= __tree_mod_log_insert(fs_info
, tm
);
754 tree_mod_log_write_unlock(fs_info
);
763 for (i
= 0; i
< nritems
; i
++)
772 static struct tree_mod_elem
*
773 __tree_mod_log_search(struct btrfs_fs_info
*fs_info
, u64 start
, u64 min_seq
,
776 struct rb_root
*tm_root
;
777 struct rb_node
*node
;
778 struct tree_mod_elem
*cur
= NULL
;
779 struct tree_mod_elem
*found
= NULL
;
780 u64 index
= start
>> PAGE_CACHE_SHIFT
;
782 tree_mod_log_read_lock(fs_info
);
783 tm_root
= &fs_info
->tree_mod_log
;
784 node
= tm_root
->rb_node
;
786 cur
= container_of(node
, struct tree_mod_elem
, node
);
787 if (cur
->index
< index
) {
788 node
= node
->rb_left
;
789 } else if (cur
->index
> index
) {
790 node
= node
->rb_right
;
791 } else if (cur
->seq
< min_seq
) {
792 node
= node
->rb_left
;
793 } else if (!smallest
) {
794 /* we want the node with the highest seq */
796 BUG_ON(found
->seq
> cur
->seq
);
798 node
= node
->rb_left
;
799 } else if (cur
->seq
> min_seq
) {
800 /* we want the node with the smallest seq */
802 BUG_ON(found
->seq
< cur
->seq
);
804 node
= node
->rb_right
;
810 tree_mod_log_read_unlock(fs_info
);
816 * this returns the element from the log with the smallest time sequence
817 * value that's in the log (the oldest log item). any element with a time
818 * sequence lower than min_seq will be ignored.
820 static struct tree_mod_elem
*
821 tree_mod_log_search_oldest(struct btrfs_fs_info
*fs_info
, u64 start
,
824 return __tree_mod_log_search(fs_info
, start
, min_seq
, 1);
828 * this returns the element from the log with the largest time sequence
829 * value that's in the log (the most recent log item). any element with
830 * a time sequence lower than min_seq will be ignored.
832 static struct tree_mod_elem
*
833 tree_mod_log_search(struct btrfs_fs_info
*fs_info
, u64 start
, u64 min_seq
)
835 return __tree_mod_log_search(fs_info
, start
, min_seq
, 0);
839 tree_mod_log_eb_copy(struct btrfs_fs_info
*fs_info
, struct extent_buffer
*dst
,
840 struct extent_buffer
*src
, unsigned long dst_offset
,
841 unsigned long src_offset
, int nr_items
)
844 struct tree_mod_elem
**tm_list
= NULL
;
845 struct tree_mod_elem
**tm_list_add
, **tm_list_rem
;
849 if (!tree_mod_need_log(fs_info
, NULL
))
852 if (btrfs_header_level(dst
) == 0 && btrfs_header_level(src
) == 0)
855 tm_list
= kzalloc(nr_items
* 2 * sizeof(struct tree_mod_elem
*),
860 tm_list_add
= tm_list
;
861 tm_list_rem
= tm_list
+ nr_items
;
862 for (i
= 0; i
< nr_items
; i
++) {
863 tm_list_rem
[i
] = alloc_tree_mod_elem(src
, i
+ src_offset
,
864 MOD_LOG_KEY_REMOVE
, GFP_NOFS
);
865 if (!tm_list_rem
[i
]) {
870 tm_list_add
[i
] = alloc_tree_mod_elem(dst
, i
+ dst_offset
,
871 MOD_LOG_KEY_ADD
, GFP_NOFS
);
872 if (!tm_list_add
[i
]) {
878 if (tree_mod_dont_log(fs_info
, NULL
))
882 for (i
= 0; i
< nr_items
; i
++) {
883 ret
= __tree_mod_log_insert(fs_info
, tm_list_rem
[i
]);
886 ret
= __tree_mod_log_insert(fs_info
, tm_list_add
[i
]);
891 tree_mod_log_write_unlock(fs_info
);
897 for (i
= 0; i
< nr_items
* 2; i
++) {
898 if (tm_list
[i
] && !RB_EMPTY_NODE(&tm_list
[i
]->node
))
899 rb_erase(&tm_list
[i
]->node
, &fs_info
->tree_mod_log
);
903 tree_mod_log_write_unlock(fs_info
);
910 tree_mod_log_eb_move(struct btrfs_fs_info
*fs_info
, struct extent_buffer
*dst
,
911 int dst_offset
, int src_offset
, int nr_items
)
914 ret
= tree_mod_log_insert_move(fs_info
, dst
, dst_offset
, src_offset
,
920 tree_mod_log_set_node_key(struct btrfs_fs_info
*fs_info
,
921 struct extent_buffer
*eb
, int slot
, int atomic
)
925 ret
= tree_mod_log_insert_key(fs_info
, eb
, slot
,
927 atomic
? GFP_ATOMIC
: GFP_NOFS
);
932 tree_mod_log_free_eb(struct btrfs_fs_info
*fs_info
, struct extent_buffer
*eb
)
934 struct tree_mod_elem
**tm_list
= NULL
;
939 if (btrfs_header_level(eb
) == 0)
942 if (!tree_mod_need_log(fs_info
, NULL
))
945 nritems
= btrfs_header_nritems(eb
);
946 tm_list
= kzalloc(nritems
* sizeof(struct tree_mod_elem
*),
951 for (i
= 0; i
< nritems
; i
++) {
952 tm_list
[i
] = alloc_tree_mod_elem(eb
, i
,
953 MOD_LOG_KEY_REMOVE_WHILE_FREEING
, GFP_NOFS
);
960 if (tree_mod_dont_log(fs_info
, eb
))
963 ret
= __tree_mod_log_free_eb(fs_info
, tm_list
, nritems
);
964 tree_mod_log_write_unlock(fs_info
);
972 for (i
= 0; i
< nritems
; i
++)
980 tree_mod_log_set_root_pointer(struct btrfs_root
*root
,
981 struct extent_buffer
*new_root_node
,
985 ret
= tree_mod_log_insert_root(root
->fs_info
, root
->node
,
986 new_root_node
, GFP_NOFS
, log_removal
);
991 * check if the tree block can be shared by multiple trees
993 int btrfs_block_can_be_shared(struct btrfs_root
*root
,
994 struct extent_buffer
*buf
)
997 * Tree blocks not in refernece counted trees and tree roots
998 * are never shared. If a block was allocated after the last
999 * snapshot and the block was not allocated by tree relocation,
1000 * we know the block is not shared.
1002 if (test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
1003 buf
!= root
->node
&& buf
!= root
->commit_root
&&
1004 (btrfs_header_generation(buf
) <=
1005 btrfs_root_last_snapshot(&root
->root_item
) ||
1006 btrfs_header_flag(buf
, BTRFS_HEADER_FLAG_RELOC
)))
1008 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1009 if (test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
1010 btrfs_header_backref_rev(buf
) < BTRFS_MIXED_BACKREF_REV
)
1016 static noinline
int update_ref_for_cow(struct btrfs_trans_handle
*trans
,
1017 struct btrfs_root
*root
,
1018 struct extent_buffer
*buf
,
1019 struct extent_buffer
*cow
,
1029 * Backrefs update rules:
1031 * Always use full backrefs for extent pointers in tree block
1032 * allocated by tree relocation.
1034 * If a shared tree block is no longer referenced by its owner
1035 * tree (btrfs_header_owner(buf) == root->root_key.objectid),
1036 * use full backrefs for extent pointers in tree block.
1038 * If a tree block is been relocating
1039 * (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID),
1040 * use full backrefs for extent pointers in tree block.
1041 * The reason for this is some operations (such as drop tree)
1042 * are only allowed for blocks use full backrefs.
1045 if (btrfs_block_can_be_shared(root
, buf
)) {
1046 ret
= btrfs_lookup_extent_info(trans
, root
, buf
->start
,
1047 btrfs_header_level(buf
), 1,
1053 btrfs_std_error(root
->fs_info
, ret
);
1058 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
||
1059 btrfs_header_backref_rev(buf
) < BTRFS_MIXED_BACKREF_REV
)
1060 flags
= BTRFS_BLOCK_FLAG_FULL_BACKREF
;
1065 owner
= btrfs_header_owner(buf
);
1066 BUG_ON(owner
== BTRFS_TREE_RELOC_OBJECTID
&&
1067 !(flags
& BTRFS_BLOCK_FLAG_FULL_BACKREF
));
1070 if ((owner
== root
->root_key
.objectid
||
1071 root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
) &&
1072 !(flags
& BTRFS_BLOCK_FLAG_FULL_BACKREF
)) {
1073 ret
= btrfs_inc_ref(trans
, root
, buf
, 1, 1);
1074 BUG_ON(ret
); /* -ENOMEM */
1076 if (root
->root_key
.objectid
==
1077 BTRFS_TREE_RELOC_OBJECTID
) {
1078 ret
= btrfs_dec_ref(trans
, root
, buf
, 0, 1);
1079 BUG_ON(ret
); /* -ENOMEM */
1080 ret
= btrfs_inc_ref(trans
, root
, cow
, 1, 1);
1081 BUG_ON(ret
); /* -ENOMEM */
1083 new_flags
|= BTRFS_BLOCK_FLAG_FULL_BACKREF
;
1086 if (root
->root_key
.objectid
==
1087 BTRFS_TREE_RELOC_OBJECTID
)
1088 ret
= btrfs_inc_ref(trans
, root
, cow
, 1, 1);
1090 ret
= btrfs_inc_ref(trans
, root
, cow
, 0, 1);
1091 BUG_ON(ret
); /* -ENOMEM */
1093 if (new_flags
!= 0) {
1094 int level
= btrfs_header_level(buf
);
1096 ret
= btrfs_set_disk_extent_flags(trans
, root
,
1099 new_flags
, level
, 0);
1104 if (flags
& BTRFS_BLOCK_FLAG_FULL_BACKREF
) {
1105 if (root
->root_key
.objectid
==
1106 BTRFS_TREE_RELOC_OBJECTID
)
1107 ret
= btrfs_inc_ref(trans
, root
, cow
, 1, 1);
1109 ret
= btrfs_inc_ref(trans
, root
, cow
, 0, 1);
1110 BUG_ON(ret
); /* -ENOMEM */
1111 ret
= btrfs_dec_ref(trans
, root
, buf
, 1, 1);
1112 BUG_ON(ret
); /* -ENOMEM */
1114 clean_tree_block(trans
, root
, buf
);
1121 * does the dirty work in cow of a single block. The parent block (if
1122 * supplied) is updated to point to the new cow copy. The new buffer is marked
1123 * dirty and returned locked. If you modify the block it needs to be marked
1126 * search_start -- an allocation hint for the new block
1128 * empty_size -- a hint that you plan on doing more cow. This is the size in
1129 * bytes the allocator should try to find free next to the block it returns.
1130 * This is just a hint and may be ignored by the allocator.
1132 static noinline
int __btrfs_cow_block(struct btrfs_trans_handle
*trans
,
1133 struct btrfs_root
*root
,
1134 struct extent_buffer
*buf
,
1135 struct extent_buffer
*parent
, int parent_slot
,
1136 struct extent_buffer
**cow_ret
,
1137 u64 search_start
, u64 empty_size
)
1139 struct btrfs_disk_key disk_key
;
1140 struct extent_buffer
*cow
;
1143 int unlock_orig
= 0;
1146 if (*cow_ret
== buf
)
1149 btrfs_assert_tree_locked(buf
);
1151 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
1152 trans
->transid
!= root
->fs_info
->running_transaction
->transid
);
1153 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
) &&
1154 trans
->transid
!= root
->last_trans
);
1156 level
= btrfs_header_level(buf
);
1159 btrfs_item_key(buf
, &disk_key
, 0);
1161 btrfs_node_key(buf
, &disk_key
, 0);
1163 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
) {
1165 parent_start
= parent
->start
;
1171 cow
= btrfs_alloc_free_block(trans
, root
, buf
->len
, parent_start
,
1172 root
->root_key
.objectid
, &disk_key
,
1173 level
, search_start
, empty_size
);
1175 return PTR_ERR(cow
);
1177 /* cow is set to blocking by btrfs_init_new_buffer */
1179 copy_extent_buffer(cow
, buf
, 0, 0, cow
->len
);
1180 btrfs_set_header_bytenr(cow
, cow
->start
);
1181 btrfs_set_header_generation(cow
, trans
->transid
);
1182 btrfs_set_header_backref_rev(cow
, BTRFS_MIXED_BACKREF_REV
);
1183 btrfs_clear_header_flag(cow
, BTRFS_HEADER_FLAG_WRITTEN
|
1184 BTRFS_HEADER_FLAG_RELOC
);
1185 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
)
1186 btrfs_set_header_flag(cow
, BTRFS_HEADER_FLAG_RELOC
);
1188 btrfs_set_header_owner(cow
, root
->root_key
.objectid
);
1190 write_extent_buffer(cow
, root
->fs_info
->fsid
, btrfs_header_fsid(),
1193 ret
= update_ref_for_cow(trans
, root
, buf
, cow
, &last_ref
);
1195 btrfs_abort_transaction(trans
, root
, ret
);
1199 if (test_bit(BTRFS_ROOT_REF_COWS
, &root
->state
)) {
1200 ret
= btrfs_reloc_cow_block(trans
, root
, buf
, cow
);
1205 if (buf
== root
->node
) {
1206 WARN_ON(parent
&& parent
!= buf
);
1207 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
||
1208 btrfs_header_backref_rev(buf
) < BTRFS_MIXED_BACKREF_REV
)
1209 parent_start
= buf
->start
;
1213 extent_buffer_get(cow
);
1214 tree_mod_log_set_root_pointer(root
, cow
, 1);
1215 rcu_assign_pointer(root
->node
, cow
);
1217 btrfs_free_tree_block(trans
, root
, buf
, parent_start
,
1219 free_extent_buffer(buf
);
1220 add_root_to_dirty_list(root
);
1222 if (root
->root_key
.objectid
== BTRFS_TREE_RELOC_OBJECTID
)
1223 parent_start
= parent
->start
;
1227 WARN_ON(trans
->transid
!= btrfs_header_generation(parent
));
1228 tree_mod_log_insert_key(root
->fs_info
, parent
, parent_slot
,
1229 MOD_LOG_KEY_REPLACE
, GFP_NOFS
);
1230 btrfs_set_node_blockptr(parent
, parent_slot
,
1232 btrfs_set_node_ptr_generation(parent
, parent_slot
,
1234 btrfs_mark_buffer_dirty(parent
);
1236 ret
= tree_mod_log_free_eb(root
->fs_info
, buf
);
1238 btrfs_abort_transaction(trans
, root
, ret
);
1242 btrfs_free_tree_block(trans
, root
, buf
, parent_start
,
1246 btrfs_tree_unlock(buf
);
1247 free_extent_buffer_stale(buf
);
1248 btrfs_mark_buffer_dirty(cow
);
1254 * returns the logical address of the oldest predecessor of the given root.
1255 * entries older than time_seq are ignored.
1257 static struct tree_mod_elem
*
1258 __tree_mod_log_oldest_root(struct btrfs_fs_info
*fs_info
,
1259 struct extent_buffer
*eb_root
, u64 time_seq
)
1261 struct tree_mod_elem
*tm
;
1262 struct tree_mod_elem
*found
= NULL
;
1263 u64 root_logical
= eb_root
->start
;
1270 * the very last operation that's logged for a root is the replacement
1271 * operation (if it is replaced at all). this has the index of the *new*
1272 * root, making it the very first operation that's logged for this root.
1275 tm
= tree_mod_log_search_oldest(fs_info
, root_logical
,
1280 * if there are no tree operation for the oldest root, we simply
1281 * return it. this should only happen if that (old) root is at
1288 * if there's an operation that's not a root replacement, we
1289 * found the oldest version of our root. normally, we'll find a
1290 * MOD_LOG_KEY_REMOVE_WHILE_FREEING operation here.
1292 if (tm
->op
!= MOD_LOG_ROOT_REPLACE
)
1296 root_logical
= tm
->old_root
.logical
;
1300 /* if there's no old root to return, return what we found instead */
1308 * tm is a pointer to the first operation to rewind within eb. then, all
1309 * previous operations will be rewinded (until we reach something older than
1313 __tree_mod_log_rewind(struct btrfs_fs_info
*fs_info
, struct extent_buffer
*eb
,
1314 u64 time_seq
, struct tree_mod_elem
*first_tm
)
1317 struct rb_node
*next
;
1318 struct tree_mod_elem
*tm
= first_tm
;
1319 unsigned long o_dst
;
1320 unsigned long o_src
;
1321 unsigned long p_size
= sizeof(struct btrfs_key_ptr
);
1323 n
= btrfs_header_nritems(eb
);
1324 tree_mod_log_read_lock(fs_info
);
1325 while (tm
&& tm
->seq
>= time_seq
) {
1327 * all the operations are recorded with the operator used for
1328 * the modification. as we're going backwards, we do the
1329 * opposite of each operation here.
1332 case MOD_LOG_KEY_REMOVE_WHILE_FREEING
:
1333 BUG_ON(tm
->slot
< n
);
1335 case MOD_LOG_KEY_REMOVE_WHILE_MOVING
:
1336 case MOD_LOG_KEY_REMOVE
:
1337 btrfs_set_node_key(eb
, &tm
->key
, tm
->slot
);
1338 btrfs_set_node_blockptr(eb
, tm
->slot
, tm
->blockptr
);
1339 btrfs_set_node_ptr_generation(eb
, tm
->slot
,
1343 case MOD_LOG_KEY_REPLACE
:
1344 BUG_ON(tm
->slot
>= n
);
1345 btrfs_set_node_key(eb
, &tm
->key
, tm
->slot
);
1346 btrfs_set_node_blockptr(eb
, tm
->slot
, tm
->blockptr
);
1347 btrfs_set_node_ptr_generation(eb
, tm
->slot
,
1350 case MOD_LOG_KEY_ADD
:
1351 /* if a move operation is needed it's in the log */
1354 case MOD_LOG_MOVE_KEYS
:
1355 o_dst
= btrfs_node_key_ptr_offset(tm
->slot
);
1356 o_src
= btrfs_node_key_ptr_offset(tm
->move
.dst_slot
);
1357 memmove_extent_buffer(eb
, o_dst
, o_src
,
1358 tm
->move
.nr_items
* p_size
);
1360 case MOD_LOG_ROOT_REPLACE
:
1362 * this operation is special. for roots, this must be
1363 * handled explicitly before rewinding.
1364 * for non-roots, this operation may exist if the node
1365 * was a root: root A -> child B; then A gets empty and
1366 * B is promoted to the new root. in the mod log, we'll
1367 * have a root-replace operation for B, a tree block
1368 * that is no root. we simply ignore that operation.
1372 next
= rb_next(&tm
->node
);
1375 tm
= container_of(next
, struct tree_mod_elem
, node
);
1376 if (tm
->index
!= first_tm
->index
)
1379 tree_mod_log_read_unlock(fs_info
);
1380 btrfs_set_header_nritems(eb
, n
);
1384 * Called with eb read locked. If the buffer cannot be rewinded, the same buffer
1385 * is returned. If rewind operations happen, a fresh buffer is returned. The
1386 * returned buffer is always read-locked. If the returned buffer is not the
1387 * input buffer, the lock on the input buffer is released and the input buffer
1388 * is freed (its refcount is decremented).
1390 static struct extent_buffer
*
1391 tree_mod_log_rewind(struct btrfs_fs_info
*fs_info
, struct btrfs_path
*path
,
1392 struct extent_buffer
*eb
, u64 time_seq
)
1394 struct extent_buffer
*eb_rewin
;
1395 struct tree_mod_elem
*tm
;
1400 if (btrfs_header_level(eb
) == 0)
1403 tm
= tree_mod_log_search(fs_info
, eb
->start
, time_seq
);
1407 btrfs_set_path_blocking(path
);
1408 btrfs_set_lock_blocking_rw(eb
, BTRFS_READ_LOCK
);
1410 if (tm
->op
== MOD_LOG_KEY_REMOVE_WHILE_FREEING
) {
1411 BUG_ON(tm
->slot
!= 0);
1412 eb_rewin
= alloc_dummy_extent_buffer(eb
->start
,
1413 fs_info
->tree_root
->nodesize
);
1415 btrfs_tree_read_unlock_blocking(eb
);
1416 free_extent_buffer(eb
);
1419 btrfs_set_header_bytenr(eb_rewin
, eb
->start
);
1420 btrfs_set_header_backref_rev(eb_rewin
,
1421 btrfs_header_backref_rev(eb
));
1422 btrfs_set_header_owner(eb_rewin
, btrfs_header_owner(eb
));
1423 btrfs_set_header_level(eb_rewin
, btrfs_header_level(eb
));
1425 eb_rewin
= btrfs_clone_extent_buffer(eb
);
1427 btrfs_tree_read_unlock_blocking(eb
);
1428 free_extent_buffer(eb
);
1433 btrfs_clear_path_blocking(path
, NULL
, BTRFS_READ_LOCK
);
1434 btrfs_tree_read_unlock_blocking(eb
);
1435 free_extent_buffer(eb
);
1437 extent_buffer_get(eb_rewin
);
1438 btrfs_tree_read_lock(eb_rewin
);
1439 __tree_mod_log_rewind(fs_info
, eb_rewin
, time_seq
, tm
);
1440 WARN_ON(btrfs_header_nritems(eb_rewin
) >
1441 BTRFS_NODEPTRS_PER_BLOCK(fs_info
->tree_root
));
1447 * get_old_root() rewinds the state of @root's root node to the given @time_seq
1448 * value. If there are no changes, the current root->root_node is returned. If
1449 * anything changed in between, there's a fresh buffer allocated on which the
1450 * rewind operations are done. In any case, the returned buffer is read locked.
1451 * Returns NULL on error (with no locks held).
1453 static inline struct extent_buffer
*
1454 get_old_root(struct btrfs_root
*root
, u64 time_seq
)
1456 struct tree_mod_elem
*tm
;
1457 struct extent_buffer
*eb
= NULL
;
1458 struct extent_buffer
*eb_root
;
1459 struct extent_buffer
*old
;
1460 struct tree_mod_root
*old_root
= NULL
;
1461 u64 old_generation
= 0;
1465 eb_root
= btrfs_read_lock_root_node(root
);
1466 tm
= __tree_mod_log_oldest_root(root
->fs_info
, eb_root
, time_seq
);
1470 if (tm
->op
== MOD_LOG_ROOT_REPLACE
) {
1471 old_root
= &tm
->old_root
;
1472 old_generation
= tm
->generation
;
1473 logical
= old_root
->logical
;
1475 logical
= eb_root
->start
;
1478 tm
= tree_mod_log_search(root
->fs_info
, logical
, time_seq
);
1479 if (old_root
&& tm
&& tm
->op
!= MOD_LOG_KEY_REMOVE_WHILE_FREEING
) {
1480 btrfs_tree_read_unlock(eb_root
);
1481 free_extent_buffer(eb_root
);
1482 blocksize
= btrfs_level_size(root
, old_root
->level
);
1483 old
= read_tree_block(root
, logical
, blocksize
, 0);
1484 if (WARN_ON(!old
|| !extent_buffer_uptodate(old
))) {
1485 free_extent_buffer(old
);
1486 btrfs_warn(root
->fs_info
,
1487 "failed to read tree block %llu from get_old_root", logical
);
1489 eb
= btrfs_clone_extent_buffer(old
);
1490 free_extent_buffer(old
);
1492 } else if (old_root
) {
1493 btrfs_tree_read_unlock(eb_root
);
1494 free_extent_buffer(eb_root
);
1495 eb
= alloc_dummy_extent_buffer(logical
, root
->nodesize
);
1497 btrfs_set_lock_blocking_rw(eb_root
, BTRFS_READ_LOCK
);
1498 eb
= btrfs_clone_extent_buffer(eb_root
);
1499 btrfs_tree_read_unlock_blocking(eb_root
);
1500 free_extent_buffer(eb_root
);
1505 extent_buffer_get(eb
);
1506 btrfs_tree_read_lock(eb
);
1508 btrfs_set_header_bytenr(eb
, eb
->start
);
1509 btrfs_set_header_backref_rev(eb
, BTRFS_MIXED_BACKREF_REV
);
1510 btrfs_set_header_owner(eb
, btrfs_header_owner(eb_root
));
1511 btrfs_set_header_level(eb
, old_root
->level
);
1512 btrfs_set_header_generation(eb
, old_generation
);
1515 __tree_mod_log_rewind(root
->fs_info
, eb
, time_seq
, tm
);
1517 WARN_ON(btrfs_header_level(eb
) != 0);
1518 WARN_ON(btrfs_header_nritems(eb
) > BTRFS_NODEPTRS_PER_BLOCK(root
));
1523 int btrfs_old_root_level(struct btrfs_root
*root
, u64 time_seq
)
1525 struct tree_mod_elem
*tm
;
1527 struct extent_buffer
*eb_root
= btrfs_root_node(root
);
1529 tm
= __tree_mod_log_oldest_root(root
->fs_info
, eb_root
, time_seq
);
1530 if (tm
&& tm
->op
== MOD_LOG_ROOT_REPLACE
) {
1531 level
= tm
->old_root
.level
;
1533 level
= btrfs_header_level(eb_root
);
1535 free_extent_buffer(eb_root
);
1540 static inline int should_cow_block(struct btrfs_trans_handle
*trans
,
1541 struct btrfs_root
*root
,
1542 struct extent_buffer
*buf
)
1544 /* ensure we can see the force_cow */
1548 * We do not need to cow a block if
1549 * 1) this block is not created or changed in this transaction;
1550 * 2) this block does not belong to TREE_RELOC tree;
1551 * 3) the root is not forced COW.
1553 * What is forced COW:
1554 * when we create snapshot during commiting the transaction,
1555 * after we've finished coping src root, we must COW the shared
1556 * block to ensure the metadata consistency.
1558 if (btrfs_header_generation(buf
) == trans
->transid
&&
1559 !btrfs_header_flag(buf
, BTRFS_HEADER_FLAG_WRITTEN
) &&
1560 !(root
->root_key
.objectid
!= BTRFS_TREE_RELOC_OBJECTID
&&
1561 btrfs_header_flag(buf
, BTRFS_HEADER_FLAG_RELOC
)) &&
1562 !test_bit(BTRFS_ROOT_FORCE_COW
, &root
->state
))
1568 * cows a single block, see __btrfs_cow_block for the real work.
1569 * This version of it has extra checks so that a block isn't cow'd more than
1570 * once per transaction, as long as it hasn't been written yet
1572 noinline
int btrfs_cow_block(struct btrfs_trans_handle
*trans
,
1573 struct btrfs_root
*root
, struct extent_buffer
*buf
,
1574 struct extent_buffer
*parent
, int parent_slot
,
1575 struct extent_buffer
**cow_ret
)
1580 if (trans
->transaction
!= root
->fs_info
->running_transaction
)
1581 WARN(1, KERN_CRIT
"trans %llu running %llu\n",
1583 root
->fs_info
->running_transaction
->transid
);
1585 if (trans
->transid
!= root
->fs_info
->generation
)
1586 WARN(1, KERN_CRIT
"trans %llu running %llu\n",
1587 trans
->transid
, root
->fs_info
->generation
);
1589 if (!should_cow_block(trans
, root
, buf
)) {
1594 search_start
= buf
->start
& ~((u64
)(1024 * 1024 * 1024) - 1);
1597 btrfs_set_lock_blocking(parent
);
1598 btrfs_set_lock_blocking(buf
);
1600 ret
= __btrfs_cow_block(trans
, root
, buf
, parent
,
1601 parent_slot
, cow_ret
, search_start
, 0);
1603 trace_btrfs_cow_block(root
, buf
, *cow_ret
);
1609 * helper function for defrag to decide if two blocks pointed to by a
1610 * node are actually close by
1612 static int close_blocks(u64 blocknr
, u64 other
, u32 blocksize
)
1614 if (blocknr
< other
&& other
- (blocknr
+ blocksize
) < 32768)
1616 if (blocknr
> other
&& blocknr
- (other
+ blocksize
) < 32768)
1622 * compare two keys in a memcmp fashion
1624 static int comp_keys(struct btrfs_disk_key
*disk
, struct btrfs_key
*k2
)
1626 struct btrfs_key k1
;
1628 btrfs_disk_key_to_cpu(&k1
, disk
);
1630 return btrfs_comp_cpu_keys(&k1
, k2
);
1634 * same as comp_keys only with two btrfs_key's
1636 int btrfs_comp_cpu_keys(struct btrfs_key
*k1
, struct btrfs_key
*k2
)
1638 if (k1
->objectid
> k2
->objectid
)
1640 if (k1
->objectid
< k2
->objectid
)
1642 if (k1
->type
> k2
->type
)
1644 if (k1
->type
< k2
->type
)
1646 if (k1
->offset
> k2
->offset
)
1648 if (k1
->offset
< k2
->offset
)
1654 * this is used by the defrag code to go through all the
1655 * leaves pointed to by a node and reallocate them so that
1656 * disk order is close to key order
1658 int btrfs_realloc_node(struct btrfs_trans_handle
*trans
,
1659 struct btrfs_root
*root
, struct extent_buffer
*parent
,
1660 int start_slot
, u64
*last_ret
,
1661 struct btrfs_key
*progress
)
1663 struct extent_buffer
*cur
;
1666 u64 search_start
= *last_ret
;
1676 int progress_passed
= 0;
1677 struct btrfs_disk_key disk_key
;
1679 parent_level
= btrfs_header_level(parent
);
1681 WARN_ON(trans
->transaction
!= root
->fs_info
->running_transaction
);
1682 WARN_ON(trans
->transid
!= root
->fs_info
->generation
);
1684 parent_nritems
= btrfs_header_nritems(parent
);
1685 blocksize
= btrfs_level_size(root
, parent_level
- 1);
1686 end_slot
= parent_nritems
;
1688 if (parent_nritems
== 1)
1691 btrfs_set_lock_blocking(parent
);
1693 for (i
= start_slot
; i
< end_slot
; i
++) {
1696 btrfs_node_key(parent
, &disk_key
, i
);
1697 if (!progress_passed
&& comp_keys(&disk_key
, progress
) < 0)
1700 progress_passed
= 1;
1701 blocknr
= btrfs_node_blockptr(parent
, i
);
1702 gen
= btrfs_node_ptr_generation(parent
, i
);
1703 if (last_block
== 0)
1704 last_block
= blocknr
;
1707 other
= btrfs_node_blockptr(parent
, i
- 1);
1708 close
= close_blocks(blocknr
, other
, blocksize
);
1710 if (!close
&& i
< end_slot
- 2) {
1711 other
= btrfs_node_blockptr(parent
, i
+ 1);
1712 close
= close_blocks(blocknr
, other
, blocksize
);
1715 last_block
= blocknr
;
1719 cur
= btrfs_find_tree_block(root
, blocknr
, blocksize
);
1721 uptodate
= btrfs_buffer_uptodate(cur
, gen
, 0);
1724 if (!cur
|| !uptodate
) {
1726 cur
= read_tree_block(root
, blocknr
,
1728 if (!cur
|| !extent_buffer_uptodate(cur
)) {
1729 free_extent_buffer(cur
);
1732 } else if (!uptodate
) {
1733 err
= btrfs_read_buffer(cur
, gen
);
1735 free_extent_buffer(cur
);
1740 if (search_start
== 0)
1741 search_start
= last_block
;
1743 btrfs_tree_lock(cur
);
1744 btrfs_set_lock_blocking(cur
);
1745 err
= __btrfs_cow_block(trans
, root
, cur
, parent
, i
,
1748 (end_slot
- i
) * blocksize
));
1750 btrfs_tree_unlock(cur
);
1751 free_extent_buffer(cur
);
1754 search_start
= cur
->start
;
1755 last_block
= cur
->start
;
1756 *last_ret
= search_start
;
1757 btrfs_tree_unlock(cur
);
1758 free_extent_buffer(cur
);
1764 * The leaf data grows from end-to-front in the node.
1765 * this returns the address of the start of the last item,
1766 * which is the stop of the leaf data stack
1768 static inline unsigned int leaf_data_end(struct btrfs_root
*root
,
1769 struct extent_buffer
*leaf
)
1771 u32 nr
= btrfs_header_nritems(leaf
);
1773 return BTRFS_LEAF_DATA_SIZE(root
);
1774 return btrfs_item_offset_nr(leaf
, nr
- 1);
1779 * search for key in the extent_buffer. The items start at offset p,
1780 * and they are item_size apart. There are 'max' items in p.
1782 * the slot in the array is returned via slot, and it points to
1783 * the place where you would insert key if it is not found in
1786 * slot may point to max if the key is bigger than all of the keys
1788 static noinline
int generic_bin_search(struct extent_buffer
*eb
,
1790 int item_size
, struct btrfs_key
*key
,
1797 struct btrfs_disk_key
*tmp
= NULL
;
1798 struct btrfs_disk_key unaligned
;
1799 unsigned long offset
;
1801 unsigned long map_start
= 0;
1802 unsigned long map_len
= 0;
1805 while (low
< high
) {
1806 mid
= (low
+ high
) / 2;
1807 offset
= p
+ mid
* item_size
;
1809 if (!kaddr
|| offset
< map_start
||
1810 (offset
+ sizeof(struct btrfs_disk_key
)) >
1811 map_start
+ map_len
) {
1813 err
= map_private_extent_buffer(eb
, offset
,
1814 sizeof(struct btrfs_disk_key
),
1815 &kaddr
, &map_start
, &map_len
);
1818 tmp
= (struct btrfs_disk_key
*)(kaddr
+ offset
-
1821 read_extent_buffer(eb
, &unaligned
,
1822 offset
, sizeof(unaligned
));
1827 tmp
= (struct btrfs_disk_key
*)(kaddr
+ offset
-
1830 ret
= comp_keys(tmp
, key
);
1846 * simple bin_search frontend that does the right thing for
1849 static int bin_search(struct extent_buffer
*eb
, struct btrfs_key
*key
,
1850 int level
, int *slot
)
1853 return generic_bin_search(eb
,
1854 offsetof(struct btrfs_leaf
, items
),
1855 sizeof(struct btrfs_item
),
1856 key
, btrfs_header_nritems(eb
),
1859 return generic_bin_search(eb
,
1860 offsetof(struct btrfs_node
, ptrs
),
1861 sizeof(struct btrfs_key_ptr
),
1862 key
, btrfs_header_nritems(eb
),
1866 int btrfs_bin_search(struct extent_buffer
*eb
, struct btrfs_key
*key
,
1867 int level
, int *slot
)
1869 return bin_search(eb
, key
, level
, slot
);
1872 static void root_add_used(struct btrfs_root
*root
, u32 size
)
1874 spin_lock(&root
->accounting_lock
);
1875 btrfs_set_root_used(&root
->root_item
,
1876 btrfs_root_used(&root
->root_item
) + size
);
1877 spin_unlock(&root
->accounting_lock
);
1880 static void root_sub_used(struct btrfs_root
*root
, u32 size
)
1882 spin_lock(&root
->accounting_lock
);
1883 btrfs_set_root_used(&root
->root_item
,
1884 btrfs_root_used(&root
->root_item
) - size
);
1885 spin_unlock(&root
->accounting_lock
);
1888 /* given a node and slot number, this reads the blocks it points to. The
1889 * extent buffer is returned with a reference taken (but unlocked).
1890 * NULL is returned on error.
1892 static noinline
struct extent_buffer
*read_node_slot(struct btrfs_root
*root
,
1893 struct extent_buffer
*parent
, int slot
)
1895 int level
= btrfs_header_level(parent
);
1896 struct extent_buffer
*eb
;
1900 if (slot
>= btrfs_header_nritems(parent
))
1905 eb
= read_tree_block(root
, btrfs_node_blockptr(parent
, slot
),
1906 btrfs_level_size(root
, level
- 1),
1907 btrfs_node_ptr_generation(parent
, slot
));
1908 if (eb
&& !extent_buffer_uptodate(eb
)) {
1909 free_extent_buffer(eb
);
1917 * node level balancing, used to make sure nodes are in proper order for
1918 * item deletion. We balance from the top down, so we have to make sure
1919 * that a deletion won't leave an node completely empty later on.
1921 static noinline
int balance_level(struct btrfs_trans_handle
*trans
,
1922 struct btrfs_root
*root
,
1923 struct btrfs_path
*path
, int level
)
1925 struct extent_buffer
*right
= NULL
;
1926 struct extent_buffer
*mid
;
1927 struct extent_buffer
*left
= NULL
;
1928 struct extent_buffer
*parent
= NULL
;
1932 int orig_slot
= path
->slots
[level
];
1938 mid
= path
->nodes
[level
];
1940 WARN_ON(path
->locks
[level
] != BTRFS_WRITE_LOCK
&&
1941 path
->locks
[level
] != BTRFS_WRITE_LOCK_BLOCKING
);
1942 WARN_ON(btrfs_header_generation(mid
) != trans
->transid
);
1944 orig_ptr
= btrfs_node_blockptr(mid
, orig_slot
);
1946 if (level
< BTRFS_MAX_LEVEL
- 1) {
1947 parent
= path
->nodes
[level
+ 1];
1948 pslot
= path
->slots
[level
+ 1];
1952 * deal with the case where there is only one pointer in the root
1953 * by promoting the node below to a root
1956 struct extent_buffer
*child
;
1958 if (btrfs_header_nritems(mid
) != 1)
1961 /* promote the child to a root */
1962 child
= read_node_slot(root
, mid
, 0);
1965 btrfs_std_error(root
->fs_info
, ret
);
1969 btrfs_tree_lock(child
);
1970 btrfs_set_lock_blocking(child
);
1971 ret
= btrfs_cow_block(trans
, root
, child
, mid
, 0, &child
);
1973 btrfs_tree_unlock(child
);
1974 free_extent_buffer(child
);
1978 tree_mod_log_set_root_pointer(root
, child
, 1);
1979 rcu_assign_pointer(root
->node
, child
);
1981 add_root_to_dirty_list(root
);
1982 btrfs_tree_unlock(child
);
1984 path
->locks
[level
] = 0;
1985 path
->nodes
[level
] = NULL
;
1986 clean_tree_block(trans
, root
, mid
);
1987 btrfs_tree_unlock(mid
);
1988 /* once for the path */
1989 free_extent_buffer(mid
);
1991 root_sub_used(root
, mid
->len
);
1992 btrfs_free_tree_block(trans
, root
, mid
, 0, 1);
1993 /* once for the root ptr */
1994 free_extent_buffer_stale(mid
);
1997 if (btrfs_header_nritems(mid
) >
1998 BTRFS_NODEPTRS_PER_BLOCK(root
) / 4)
2001 left
= read_node_slot(root
, parent
, pslot
- 1);
2003 btrfs_tree_lock(left
);
2004 btrfs_set_lock_blocking(left
);
2005 wret
= btrfs_cow_block(trans
, root
, left
,
2006 parent
, pslot
- 1, &left
);
2012 right
= read_node_slot(root
, parent
, pslot
+ 1);
2014 btrfs_tree_lock(right
);
2015 btrfs_set_lock_blocking(right
);
2016 wret
= btrfs_cow_block(trans
, root
, right
,
2017 parent
, pslot
+ 1, &right
);
2024 /* first, try to make some room in the middle buffer */
2026 orig_slot
+= btrfs_header_nritems(left
);
2027 wret
= push_node_left(trans
, root
, left
, mid
, 1);
2033 * then try to empty the right most buffer into the middle
2036 wret
= push_node_left(trans
, root
, mid
, right
, 1);
2037 if (wret
< 0 && wret
!= -ENOSPC
)
2039 if (btrfs_header_nritems(right
) == 0) {
2040 clean_tree_block(trans
, root
, right
);
2041 btrfs_tree_unlock(right
);
2042 del_ptr(root
, path
, level
+ 1, pslot
+ 1);
2043 root_sub_used(root
, right
->len
);
2044 btrfs_free_tree_block(trans
, root
, right
, 0, 1);
2045 free_extent_buffer_stale(right
);
2048 struct btrfs_disk_key right_key
;
2049 btrfs_node_key(right
, &right_key
, 0);
2050 tree_mod_log_set_node_key(root
->fs_info
, parent
,
2052 btrfs_set_node_key(parent
, &right_key
, pslot
+ 1);
2053 btrfs_mark_buffer_dirty(parent
);
2056 if (btrfs_header_nritems(mid
) == 1) {
2058 * we're not allowed to leave a node with one item in the
2059 * tree during a delete. A deletion from lower in the tree
2060 * could try to delete the only pointer in this node.
2061 * So, pull some keys from the left.
2062 * There has to be a left pointer at this point because
2063 * otherwise we would have pulled some pointers from the
2068 btrfs_std_error(root
->fs_info
, ret
);
2071 wret
= balance_node_right(trans
, root
, mid
, left
);
2077 wret
= push_node_left(trans
, root
, left
, mid
, 1);
2083 if (btrfs_header_nritems(mid
) == 0) {
2084 clean_tree_block(trans
, root
, mid
);
2085 btrfs_tree_unlock(mid
);
2086 del_ptr(root
, path
, level
+ 1, pslot
);
2087 root_sub_used(root
, mid
->len
);
2088 btrfs_free_tree_block(trans
, root
, mid
, 0, 1);
2089 free_extent_buffer_stale(mid
);
2092 /* update the parent key to reflect our changes */
2093 struct btrfs_disk_key mid_key
;
2094 btrfs_node_key(mid
, &mid_key
, 0);
2095 tree_mod_log_set_node_key(root
->fs_info
, parent
,
2097 btrfs_set_node_key(parent
, &mid_key
, pslot
);
2098 btrfs_mark_buffer_dirty(parent
);
2101 /* update the path */
2103 if (btrfs_header_nritems(left
) > orig_slot
) {
2104 extent_buffer_get(left
);
2105 /* left was locked after cow */
2106 path
->nodes
[level
] = left
;
2107 path
->slots
[level
+ 1] -= 1;
2108 path
->slots
[level
] = orig_slot
;
2110 btrfs_tree_unlock(mid
);
2111 free_extent_buffer(mid
);
2114 orig_slot
-= btrfs_header_nritems(left
);
2115 path
->slots
[level
] = orig_slot
;
2118 /* double check we haven't messed things up */
2120 btrfs_node_blockptr(path
->nodes
[level
], path
->slots
[level
]))
2124 btrfs_tree_unlock(right
);
2125 free_extent_buffer(right
);
2128 if (path
->nodes
[level
] != left
)
2129 btrfs_tree_unlock(left
);
2130 free_extent_buffer(left
);
2135 /* Node balancing for insertion. Here we only split or push nodes around
2136 * when they are completely full. This is also done top down, so we
2137 * have to be pessimistic.
2139 static noinline
int push_nodes_for_insert(struct btrfs_trans_handle
*trans
,
2140 struct btrfs_root
*root
,
2141 struct btrfs_path
*path
, int level
)
2143 struct extent_buffer
*right
= NULL
;
2144 struct extent_buffer
*mid
;
2145 struct extent_buffer
*left
= NULL
;
2146 struct extent_buffer
*parent
= NULL
;
2150 int orig_slot
= path
->slots
[level
];
2155 mid
= path
->nodes
[level
];
2156 WARN_ON(btrfs_header_generation(mid
) != trans
->transid
);
2158 if (level
< BTRFS_MAX_LEVEL
- 1) {
2159 parent
= path
->nodes
[level
+ 1];
2160 pslot
= path
->slots
[level
+ 1];
2166 left
= read_node_slot(root
, parent
, pslot
- 1);
2168 /* first, try to make some room in the middle buffer */
2172 btrfs_tree_lock(left
);
2173 btrfs_set_lock_blocking(left
);
2175 left_nr
= btrfs_header_nritems(left
);
2176 if (left_nr
>= BTRFS_NODEPTRS_PER_BLOCK(root
) - 1) {
2179 ret
= btrfs_cow_block(trans
, root
, left
, parent
,
2184 wret
= push_node_left(trans
, root
,
2191 struct btrfs_disk_key disk_key
;
2192 orig_slot
+= left_nr
;
2193 btrfs_node_key(mid
, &disk_key
, 0);
2194 tree_mod_log_set_node_key(root
->fs_info
, parent
,
2196 btrfs_set_node_key(parent
, &disk_key
, pslot
);
2197 btrfs_mark_buffer_dirty(parent
);
2198 if (btrfs_header_nritems(left
) > orig_slot
) {
2199 path
->nodes
[level
] = left
;
2200 path
->slots
[level
+ 1] -= 1;
2201 path
->slots
[level
] = orig_slot
;
2202 btrfs_tree_unlock(mid
);
2203 free_extent_buffer(mid
);
2206 btrfs_header_nritems(left
);
2207 path
->slots
[level
] = orig_slot
;
2208 btrfs_tree_unlock(left
);
2209 free_extent_buffer(left
);
2213 btrfs_tree_unlock(left
);
2214 free_extent_buffer(left
);
2216 right
= read_node_slot(root
, parent
, pslot
+ 1);
2219 * then try to empty the right most buffer into the middle
2224 btrfs_tree_lock(right
);
2225 btrfs_set_lock_blocking(right
);
2227 right_nr
= btrfs_header_nritems(right
);
2228 if (right_nr
>= BTRFS_NODEPTRS_PER_BLOCK(root
) - 1) {
2231 ret
= btrfs_cow_block(trans
, root
, right
,
2237 wret
= balance_node_right(trans
, root
,
2244 struct btrfs_disk_key disk_key
;
2246 btrfs_node_key(right
, &disk_key
, 0);
2247 tree_mod_log_set_node_key(root
->fs_info
, parent
,
2249 btrfs_set_node_key(parent
, &disk_key
, pslot
+ 1);
2250 btrfs_mark_buffer_dirty(parent
);
2252 if (btrfs_header_nritems(mid
) <= orig_slot
) {
2253 path
->nodes
[level
] = right
;
2254 path
->slots
[level
+ 1] += 1;
2255 path
->slots
[level
] = orig_slot
-
2256 btrfs_header_nritems(mid
);
2257 btrfs_tree_unlock(mid
);
2258 free_extent_buffer(mid
);
2260 btrfs_tree_unlock(right
);
2261 free_extent_buffer(right
);
2265 btrfs_tree_unlock(right
);
2266 free_extent_buffer(right
);
2272 * readahead one full node of leaves, finding things that are close
2273 * to the block in 'slot', and triggering ra on them.
2275 static void reada_for_search(struct btrfs_root
*root
,
2276 struct btrfs_path
*path
,
2277 int level
, int slot
, u64 objectid
)
2279 struct extent_buffer
*node
;
2280 struct btrfs_disk_key disk_key
;
2286 int direction
= path
->reada
;
2287 struct extent_buffer
*eb
;
2295 if (!path
->nodes
[level
])
2298 node
= path
->nodes
[level
];
2300 search
= btrfs_node_blockptr(node
, slot
);
2301 blocksize
= btrfs_level_size(root
, level
- 1);
2302 eb
= btrfs_find_tree_block(root
, search
, blocksize
);
2304 free_extent_buffer(eb
);
2310 nritems
= btrfs_header_nritems(node
);
2314 if (direction
< 0) {
2318 } else if (direction
> 0) {
2323 if (path
->reada
< 0 && objectid
) {
2324 btrfs_node_key(node
, &disk_key
, nr
);
2325 if (btrfs_disk_key_objectid(&disk_key
) != objectid
)
2328 search
= btrfs_node_blockptr(node
, nr
);
2329 if ((search
<= target
&& target
- search
<= 65536) ||
2330 (search
> target
&& search
- target
<= 65536)) {
2331 gen
= btrfs_node_ptr_generation(node
, nr
);
2332 readahead_tree_block(root
, search
, blocksize
, gen
);
2336 if ((nread
> 65536 || nscan
> 32))
2341 static noinline
void reada_for_balance(struct btrfs_root
*root
,
2342 struct btrfs_path
*path
, int level
)
2346 struct extent_buffer
*parent
;
2347 struct extent_buffer
*eb
;
2353 parent
= path
->nodes
[level
+ 1];
2357 nritems
= btrfs_header_nritems(parent
);
2358 slot
= path
->slots
[level
+ 1];
2359 blocksize
= btrfs_level_size(root
, level
);
2362 block1
= btrfs_node_blockptr(parent
, slot
- 1);
2363 gen
= btrfs_node_ptr_generation(parent
, slot
- 1);
2364 eb
= btrfs_find_tree_block(root
, block1
, blocksize
);
2366 * if we get -eagain from btrfs_buffer_uptodate, we
2367 * don't want to return eagain here. That will loop
2370 if (eb
&& btrfs_buffer_uptodate(eb
, gen
, 1) != 0)
2372 free_extent_buffer(eb
);
2374 if (slot
+ 1 < nritems
) {
2375 block2
= btrfs_node_blockptr(parent
, slot
+ 1);
2376 gen
= btrfs_node_ptr_generation(parent
, slot
+ 1);
2377 eb
= btrfs_find_tree_block(root
, block2
, blocksize
);
2378 if (eb
&& btrfs_buffer_uptodate(eb
, gen
, 1) != 0)
2380 free_extent_buffer(eb
);
2384 readahead_tree_block(root
, block1
, blocksize
, 0);
2386 readahead_tree_block(root
, block2
, blocksize
, 0);
2391 * when we walk down the tree, it is usually safe to unlock the higher layers
2392 * in the tree. The exceptions are when our path goes through slot 0, because
2393 * operations on the tree might require changing key pointers higher up in the
2396 * callers might also have set path->keep_locks, which tells this code to keep
2397 * the lock if the path points to the last slot in the block. This is part of
2398 * walking through the tree, and selecting the next slot in the higher block.
2400 * lowest_unlock sets the lowest level in the tree we're allowed to unlock. so
2401 * if lowest_unlock is 1, level 0 won't be unlocked
2403 static noinline
void unlock_up(struct btrfs_path
*path
, int level
,
2404 int lowest_unlock
, int min_write_lock_level
,
2405 int *write_lock_level
)
2408 int skip_level
= level
;
2410 struct extent_buffer
*t
;
2412 for (i
= level
; i
< BTRFS_MAX_LEVEL
; i
++) {
2413 if (!path
->nodes
[i
])
2415 if (!path
->locks
[i
])
2417 if (!no_skips
&& path
->slots
[i
] == 0) {
2421 if (!no_skips
&& path
->keep_locks
) {
2424 nritems
= btrfs_header_nritems(t
);
2425 if (nritems
< 1 || path
->slots
[i
] >= nritems
- 1) {
2430 if (skip_level
< i
&& i
>= lowest_unlock
)
2434 if (i
>= lowest_unlock
&& i
> skip_level
&& path
->locks
[i
]) {
2435 btrfs_tree_unlock_rw(t
, path
->locks
[i
]);
2437 if (write_lock_level
&&
2438 i
> min_write_lock_level
&&
2439 i
<= *write_lock_level
) {
2440 *write_lock_level
= i
- 1;
2447 * This releases any locks held in the path starting at level and
2448 * going all the way up to the root.
2450 * btrfs_search_slot will keep the lock held on higher nodes in a few
2451 * corner cases, such as COW of the block at slot zero in the node. This
2452 * ignores those rules, and it should only be called when there are no
2453 * more updates to be done higher up in the tree.
2455 noinline
void btrfs_unlock_up_safe(struct btrfs_path
*path
, int level
)
2459 if (path
->keep_locks
)
2462 for (i
= level
; i
< BTRFS_MAX_LEVEL
; i
++) {
2463 if (!path
->nodes
[i
])
2465 if (!path
->locks
[i
])
2467 btrfs_tree_unlock_rw(path
->nodes
[i
], path
->locks
[i
]);
2473 * helper function for btrfs_search_slot. The goal is to find a block
2474 * in cache without setting the path to blocking. If we find the block
2475 * we return zero and the path is unchanged.
2477 * If we can't find the block, we set the path blocking and do some
2478 * reada. -EAGAIN is returned and the search must be repeated.
2481 read_block_for_search(struct btrfs_trans_handle
*trans
,
2482 struct btrfs_root
*root
, struct btrfs_path
*p
,
2483 struct extent_buffer
**eb_ret
, int level
, int slot
,
2484 struct btrfs_key
*key
, u64 time_seq
)
2489 struct extent_buffer
*b
= *eb_ret
;
2490 struct extent_buffer
*tmp
;
2493 blocknr
= btrfs_node_blockptr(b
, slot
);
2494 gen
= btrfs_node_ptr_generation(b
, slot
);
2495 blocksize
= btrfs_level_size(root
, level
- 1);
2497 tmp
= btrfs_find_tree_block(root
, blocknr
, blocksize
);
2499 /* first we do an atomic uptodate check */
2500 if (btrfs_buffer_uptodate(tmp
, gen
, 1) > 0) {
2505 /* the pages were up to date, but we failed
2506 * the generation number check. Do a full
2507 * read for the generation number that is correct.
2508 * We must do this without dropping locks so
2509 * we can trust our generation number
2511 btrfs_set_path_blocking(p
);
2513 /* now we're allowed to do a blocking uptodate check */
2514 ret
= btrfs_read_buffer(tmp
, gen
);
2519 free_extent_buffer(tmp
);
2520 btrfs_release_path(p
);
2525 * reduce lock contention at high levels
2526 * of the btree by dropping locks before
2527 * we read. Don't release the lock on the current
2528 * level because we need to walk this node to figure
2529 * out which blocks to read.
2531 btrfs_unlock_up_safe(p
, level
+ 1);
2532 btrfs_set_path_blocking(p
);
2534 free_extent_buffer(tmp
);
2536 reada_for_search(root
, p
, level
, slot
, key
->objectid
);
2538 btrfs_release_path(p
);
2541 tmp
= read_tree_block(root
, blocknr
, blocksize
, 0);
2544 * If the read above didn't mark this buffer up to date,
2545 * it will never end up being up to date. Set ret to EIO now
2546 * and give up so that our caller doesn't loop forever
2549 if (!btrfs_buffer_uptodate(tmp
, 0, 0))
2551 free_extent_buffer(tmp
);
2557 * helper function for btrfs_search_slot. This does all of the checks
2558 * for node-level blocks and does any balancing required based on
2561 * If no extra work was required, zero is returned. If we had to
2562 * drop the path, -EAGAIN is returned and btrfs_search_slot must
2566 setup_nodes_for_search(struct btrfs_trans_handle
*trans
,
2567 struct btrfs_root
*root
, struct btrfs_path
*p
,
2568 struct extent_buffer
*b
, int level
, int ins_len
,
2569 int *write_lock_level
)
2572 if ((p
->search_for_split
|| ins_len
> 0) && btrfs_header_nritems(b
) >=
2573 BTRFS_NODEPTRS_PER_BLOCK(root
) - 3) {
2576 if (*write_lock_level
< level
+ 1) {
2577 *write_lock_level
= level
+ 1;
2578 btrfs_release_path(p
);
2582 btrfs_set_path_blocking(p
);
2583 reada_for_balance(root
, p
, level
);
2584 sret
= split_node(trans
, root
, p
, level
);
2585 btrfs_clear_path_blocking(p
, NULL
, 0);
2592 b
= p
->nodes
[level
];
2593 } else if (ins_len
< 0 && btrfs_header_nritems(b
) <
2594 BTRFS_NODEPTRS_PER_BLOCK(root
) / 2) {
2597 if (*write_lock_level
< level
+ 1) {
2598 *write_lock_level
= level
+ 1;
2599 btrfs_release_path(p
);
2603 btrfs_set_path_blocking(p
);
2604 reada_for_balance(root
, p
, level
);
2605 sret
= balance_level(trans
, root
, p
, level
);
2606 btrfs_clear_path_blocking(p
, NULL
, 0);
2612 b
= p
->nodes
[level
];
2614 btrfs_release_path(p
);
2617 BUG_ON(btrfs_header_nritems(b
) == 1);
2627 static void key_search_validate(struct extent_buffer
*b
,
2628 struct btrfs_key
*key
,
2631 #ifdef CONFIG_BTRFS_ASSERT
2632 struct btrfs_disk_key disk_key
;
2634 btrfs_cpu_key_to_disk(&disk_key
, key
);
2637 ASSERT(!memcmp_extent_buffer(b
, &disk_key
,
2638 offsetof(struct btrfs_leaf
, items
[0].key
),
2641 ASSERT(!memcmp_extent_buffer(b
, &disk_key
,
2642 offsetof(struct btrfs_node
, ptrs
[0].key
),
2647 static int key_search(struct extent_buffer
*b
, struct btrfs_key
*key
,
2648 int level
, int *prev_cmp
, int *slot
)
2650 if (*prev_cmp
!= 0) {
2651 *prev_cmp
= bin_search(b
, key
, level
, slot
);
2655 key_search_validate(b
, key
, level
);
2661 int btrfs_find_item(struct btrfs_root
*fs_root
, struct btrfs_path
*found_path
,
2662 u64 iobjectid
, u64 ioff
, u8 key_type
,
2663 struct btrfs_key
*found_key
)
2666 struct btrfs_key key
;
2667 struct extent_buffer
*eb
;
2668 struct btrfs_path
*path
;
2670 key
.type
= key_type
;
2671 key
.objectid
= iobjectid
;
2674 if (found_path
== NULL
) {
2675 path
= btrfs_alloc_path();
2681 ret
= btrfs_search_slot(NULL
, fs_root
, &key
, path
, 0, 0);
2682 if ((ret
< 0) || (found_key
== NULL
)) {
2683 if (path
!= found_path
)
2684 btrfs_free_path(path
);
2688 eb
= path
->nodes
[0];
2689 if (ret
&& path
->slots
[0] >= btrfs_header_nritems(eb
)) {
2690 ret
= btrfs_next_leaf(fs_root
, path
);
2693 eb
= path
->nodes
[0];
2696 btrfs_item_key_to_cpu(eb
, found_key
, path
->slots
[0]);
2697 if (found_key
->type
!= key
.type
||
2698 found_key
->objectid
!= key
.objectid
)
2705 * look for key in the tree. path is filled in with nodes along the way
2706 * if key is found, we return zero and you can find the item in the leaf
2707 * level of the path (level 0)
2709 * If the key isn't found, the path points to the slot where it should
2710 * be inserted, and 1 is returned. If there are other errors during the
2711 * search a negative error number is returned.
2713 * if ins_len > 0, nodes and leaves will be split as we walk down the
2714 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
2717 int btrfs_search_slot(struct btrfs_trans_handle
*trans
, struct btrfs_root
2718 *root
, struct btrfs_key
*key
, struct btrfs_path
*p
, int
2721 struct extent_buffer
*b
;
2726 int lowest_unlock
= 1;
2728 /* everything at write_lock_level or lower must be write locked */
2729 int write_lock_level
= 0;
2730 u8 lowest_level
= 0;
2731 int min_write_lock_level
;
2734 lowest_level
= p
->lowest_level
;
2735 WARN_ON(lowest_level
&& ins_len
> 0);
2736 WARN_ON(p
->nodes
[0] != NULL
);
2737 BUG_ON(!cow
&& ins_len
);
2742 /* when we are removing items, we might have to go up to level
2743 * two as we update tree pointers Make sure we keep write
2744 * for those levels as well
2746 write_lock_level
= 2;
2747 } else if (ins_len
> 0) {
2749 * for inserting items, make sure we have a write lock on
2750 * level 1 so we can update keys
2752 write_lock_level
= 1;
2756 write_lock_level
= -1;
2758 if (cow
&& (p
->keep_locks
|| p
->lowest_level
))
2759 write_lock_level
= BTRFS_MAX_LEVEL
;
2761 min_write_lock_level
= write_lock_level
;
2766 * we try very hard to do read locks on the root
2768 root_lock
= BTRFS_READ_LOCK
;
2770 if (p
->search_commit_root
) {
2772 * the commit roots are read only
2773 * so we always do read locks
2775 if (p
->need_commit_sem
)
2776 down_read(&root
->fs_info
->commit_root_sem
);
2777 b
= root
->commit_root
;
2778 extent_buffer_get(b
);
2779 level
= btrfs_header_level(b
);
2780 if (p
->need_commit_sem
)
2781 up_read(&root
->fs_info
->commit_root_sem
);
2782 if (!p
->skip_locking
)
2783 btrfs_tree_read_lock(b
);
2785 if (p
->skip_locking
) {
2786 b
= btrfs_root_node(root
);
2787 level
= btrfs_header_level(b
);
2789 /* we don't know the level of the root node
2790 * until we actually have it read locked
2792 b
= btrfs_read_lock_root_node(root
);
2793 level
= btrfs_header_level(b
);
2794 if (level
<= write_lock_level
) {
2795 /* whoops, must trade for write lock */
2796 btrfs_tree_read_unlock(b
);
2797 free_extent_buffer(b
);
2798 b
= btrfs_lock_root_node(root
);
2799 root_lock
= BTRFS_WRITE_LOCK
;
2801 /* the level might have changed, check again */
2802 level
= btrfs_header_level(b
);
2806 p
->nodes
[level
] = b
;
2807 if (!p
->skip_locking
)
2808 p
->locks
[level
] = root_lock
;
2811 level
= btrfs_header_level(b
);
2814 * setup the path here so we can release it under lock
2815 * contention with the cow code
2819 * if we don't really need to cow this block
2820 * then we don't want to set the path blocking,
2821 * so we test it here
2823 if (!should_cow_block(trans
, root
, b
))
2826 btrfs_set_path_blocking(p
);
2829 * must have write locks on this node and the
2832 if (level
> write_lock_level
||
2833 (level
+ 1 > write_lock_level
&&
2834 level
+ 1 < BTRFS_MAX_LEVEL
&&
2835 p
->nodes
[level
+ 1])) {
2836 write_lock_level
= level
+ 1;
2837 btrfs_release_path(p
);
2841 err
= btrfs_cow_block(trans
, root
, b
,
2842 p
->nodes
[level
+ 1],
2843 p
->slots
[level
+ 1], &b
);
2850 p
->nodes
[level
] = b
;
2851 btrfs_clear_path_blocking(p
, NULL
, 0);
2854 * we have a lock on b and as long as we aren't changing
2855 * the tree, there is no way to for the items in b to change.
2856 * It is safe to drop the lock on our parent before we
2857 * go through the expensive btree search on b.
2859 * If we're inserting or deleting (ins_len != 0), then we might
2860 * be changing slot zero, which may require changing the parent.
2861 * So, we can't drop the lock until after we know which slot
2862 * we're operating on.
2864 if (!ins_len
&& !p
->keep_locks
) {
2867 if (u
< BTRFS_MAX_LEVEL
&& p
->locks
[u
]) {
2868 btrfs_tree_unlock_rw(p
->nodes
[u
], p
->locks
[u
]);
2873 ret
= key_search(b
, key
, level
, &prev_cmp
, &slot
);
2877 if (ret
&& slot
> 0) {
2881 p
->slots
[level
] = slot
;
2882 err
= setup_nodes_for_search(trans
, root
, p
, b
, level
,
2883 ins_len
, &write_lock_level
);
2890 b
= p
->nodes
[level
];
2891 slot
= p
->slots
[level
];
2894 * slot 0 is special, if we change the key
2895 * we have to update the parent pointer
2896 * which means we must have a write lock
2899 if (slot
== 0 && ins_len
&&
2900 write_lock_level
< level
+ 1) {
2901 write_lock_level
= level
+ 1;
2902 btrfs_release_path(p
);
2906 unlock_up(p
, level
, lowest_unlock
,
2907 min_write_lock_level
, &write_lock_level
);
2909 if (level
== lowest_level
) {
2915 err
= read_block_for_search(trans
, root
, p
,
2916 &b
, level
, slot
, key
, 0);
2924 if (!p
->skip_locking
) {
2925 level
= btrfs_header_level(b
);
2926 if (level
<= write_lock_level
) {
2927 err
= btrfs_try_tree_write_lock(b
);
2929 btrfs_set_path_blocking(p
);
2931 btrfs_clear_path_blocking(p
, b
,
2934 p
->locks
[level
] = BTRFS_WRITE_LOCK
;
2936 err
= btrfs_try_tree_read_lock(b
);
2938 btrfs_set_path_blocking(p
);
2939 btrfs_tree_read_lock(b
);
2940 btrfs_clear_path_blocking(p
, b
,
2943 p
->locks
[level
] = BTRFS_READ_LOCK
;
2945 p
->nodes
[level
] = b
;
2948 p
->slots
[level
] = slot
;
2950 btrfs_leaf_free_space(root
, b
) < ins_len
) {
2951 if (write_lock_level
< 1) {
2952 write_lock_level
= 1;
2953 btrfs_release_path(p
);
2957 btrfs_set_path_blocking(p
);
2958 err
= split_leaf(trans
, root
, key
,
2959 p
, ins_len
, ret
== 0);
2960 btrfs_clear_path_blocking(p
, NULL
, 0);
2968 if (!p
->search_for_split
)
2969 unlock_up(p
, level
, lowest_unlock
,
2970 min_write_lock_level
, &write_lock_level
);
2977 * we don't really know what they plan on doing with the path
2978 * from here on, so for now just mark it as blocking
2980 if (!p
->leave_spinning
)
2981 btrfs_set_path_blocking(p
);
2983 btrfs_release_path(p
);
2988 * Like btrfs_search_slot, this looks for a key in the given tree. It uses the
2989 * current state of the tree together with the operations recorded in the tree
2990 * modification log to search for the key in a previous version of this tree, as
2991 * denoted by the time_seq parameter.
2993 * Naturally, there is no support for insert, delete or cow operations.
2995 * The resulting path and return value will be set up as if we called
2996 * btrfs_search_slot at that point in time with ins_len and cow both set to 0.
2998 int btrfs_search_old_slot(struct btrfs_root
*root
, struct btrfs_key
*key
,
2999 struct btrfs_path
*p
, u64 time_seq
)
3001 struct extent_buffer
*b
;
3006 int lowest_unlock
= 1;
3007 u8 lowest_level
= 0;
3010 lowest_level
= p
->lowest_level
;
3011 WARN_ON(p
->nodes
[0] != NULL
);
3013 if (p
->search_commit_root
) {
3015 return btrfs_search_slot(NULL
, root
, key
, p
, 0, 0);
3019 b
= get_old_root(root
, time_seq
);
3020 level
= btrfs_header_level(b
);
3021 p
->locks
[level
] = BTRFS_READ_LOCK
;
3024 level
= btrfs_header_level(b
);
3025 p
->nodes
[level
] = b
;
3026 btrfs_clear_path_blocking(p
, NULL
, 0);
3029 * we have a lock on b and as long as we aren't changing
3030 * the tree, there is no way to for the items in b to change.
3031 * It is safe to drop the lock on our parent before we
3032 * go through the expensive btree search on b.
3034 btrfs_unlock_up_safe(p
, level
+ 1);
3037 * Since we can unwind eb's we want to do a real search every
3041 ret
= key_search(b
, key
, level
, &prev_cmp
, &slot
);
3045 if (ret
&& slot
> 0) {
3049 p
->slots
[level
] = slot
;
3050 unlock_up(p
, level
, lowest_unlock
, 0, NULL
);
3052 if (level
== lowest_level
) {
3058 err
= read_block_for_search(NULL
, root
, p
, &b
, level
,
3059 slot
, key
, time_seq
);
3067 level
= btrfs_header_level(b
);
3068 err
= btrfs_try_tree_read_lock(b
);
3070 btrfs_set_path_blocking(p
);
3071 btrfs_tree_read_lock(b
);
3072 btrfs_clear_path_blocking(p
, b
,
3075 b
= tree_mod_log_rewind(root
->fs_info
, p
, b
, time_seq
);
3080 p
->locks
[level
] = BTRFS_READ_LOCK
;
3081 p
->nodes
[level
] = b
;
3083 p
->slots
[level
] = slot
;
3084 unlock_up(p
, level
, lowest_unlock
, 0, NULL
);
3090 if (!p
->leave_spinning
)
3091 btrfs_set_path_blocking(p
);
3093 btrfs_release_path(p
);
3099 * helper to use instead of search slot if no exact match is needed but
3100 * instead the next or previous item should be returned.
3101 * When find_higher is true, the next higher item is returned, the next lower
3103 * When return_any and find_higher are both true, and no higher item is found,
3104 * return the next lower instead.
3105 * When return_any is true and find_higher is false, and no lower item is found,
3106 * return the next higher instead.
3107 * It returns 0 if any item is found, 1 if none is found (tree empty), and
3110 int btrfs_search_slot_for_read(struct btrfs_root
*root
,
3111 struct btrfs_key
*key
, struct btrfs_path
*p
,
3112 int find_higher
, int return_any
)
3115 struct extent_buffer
*leaf
;
3118 ret
= btrfs_search_slot(NULL
, root
, key
, p
, 0, 0);
3122 * a return value of 1 means the path is at the position where the
3123 * item should be inserted. Normally this is the next bigger item,
3124 * but in case the previous item is the last in a leaf, path points
3125 * to the first free slot in the previous leaf, i.e. at an invalid
3131 if (p
->slots
[0] >= btrfs_header_nritems(leaf
)) {
3132 ret
= btrfs_next_leaf(root
, p
);
3138 * no higher item found, return the next
3143 btrfs_release_path(p
);
3147 if (p
->slots
[0] == 0) {
3148 ret
= btrfs_prev_leaf(root
, p
);
3153 if (p
->slots
[0] == btrfs_header_nritems(leaf
))
3160 * no lower item found, return the next
3165 btrfs_release_path(p
);
3175 * adjust the pointers going up the tree, starting at level
3176 * making sure the right key of each node is points to 'key'.
3177 * This is used after shifting pointers to the left, so it stops
3178 * fixing up pointers when a given leaf/node is not in slot 0 of the
3182 static void fixup_low_keys(struct btrfs_root
*root
, struct btrfs_path
*path
,
3183 struct btrfs_disk_key
*key
, int level
)
3186 struct extent_buffer
*t
;
3188 for (i
= level
; i
< BTRFS_MAX_LEVEL
; i
++) {
3189 int tslot
= path
->slots
[i
];
3190 if (!path
->nodes
[i
])
3193 tree_mod_log_set_node_key(root
->fs_info
, t
, tslot
, 1);
3194 btrfs_set_node_key(t
, key
, tslot
);
3195 btrfs_mark_buffer_dirty(path
->nodes
[i
]);
3204 * This function isn't completely safe. It's the caller's responsibility
3205 * that the new key won't break the order
3207 void btrfs_set_item_key_safe(struct btrfs_root
*root
, struct btrfs_path
*path
,
3208 struct btrfs_key
*new_key
)
3210 struct btrfs_disk_key disk_key
;
3211 struct extent_buffer
*eb
;
3214 eb
= path
->nodes
[0];
3215 slot
= path
->slots
[0];
3217 btrfs_item_key(eb
, &disk_key
, slot
- 1);
3218 BUG_ON(comp_keys(&disk_key
, new_key
) >= 0);
3220 if (slot
< btrfs_header_nritems(eb
) - 1) {
3221 btrfs_item_key(eb
, &disk_key
, slot
+ 1);
3222 BUG_ON(comp_keys(&disk_key
, new_key
) <= 0);
3225 btrfs_cpu_key_to_disk(&disk_key
, new_key
);
3226 btrfs_set_item_key(eb
, &disk_key
, slot
);
3227 btrfs_mark_buffer_dirty(eb
);
3229 fixup_low_keys(root
, path
, &disk_key
, 1);
3233 * try to push data from one node into the next node left in the
3236 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
3237 * error, and > 0 if there was no room in the left hand block.
3239 static int push_node_left(struct btrfs_trans_handle
*trans
,
3240 struct btrfs_root
*root
, struct extent_buffer
*dst
,
3241 struct extent_buffer
*src
, int empty
)
3248 src_nritems
= btrfs_header_nritems(src
);
3249 dst_nritems
= btrfs_header_nritems(dst
);
3250 push_items
= BTRFS_NODEPTRS_PER_BLOCK(root
) - dst_nritems
;
3251 WARN_ON(btrfs_header_generation(src
) != trans
->transid
);
3252 WARN_ON(btrfs_header_generation(dst
) != trans
->transid
);
3254 if (!empty
&& src_nritems
<= 8)
3257 if (push_items
<= 0)
3261 push_items
= min(src_nritems
, push_items
);
3262 if (push_items
< src_nritems
) {
3263 /* leave at least 8 pointers in the node if
3264 * we aren't going to empty it
3266 if (src_nritems
- push_items
< 8) {
3267 if (push_items
<= 8)
3273 push_items
= min(src_nritems
- 8, push_items
);
3275 ret
= tree_mod_log_eb_copy(root
->fs_info
, dst
, src
, dst_nritems
, 0,
3278 btrfs_abort_transaction(trans
, root
, ret
);
3281 copy_extent_buffer(dst
, src
,
3282 btrfs_node_key_ptr_offset(dst_nritems
),
3283 btrfs_node_key_ptr_offset(0),
3284 push_items
* sizeof(struct btrfs_key_ptr
));
3286 if (push_items
< src_nritems
) {
3288 * don't call tree_mod_log_eb_move here, key removal was already
3289 * fully logged by tree_mod_log_eb_copy above.
3291 memmove_extent_buffer(src
, btrfs_node_key_ptr_offset(0),
3292 btrfs_node_key_ptr_offset(push_items
),
3293 (src_nritems
- push_items
) *
3294 sizeof(struct btrfs_key_ptr
));
3296 btrfs_set_header_nritems(src
, src_nritems
- push_items
);
3297 btrfs_set_header_nritems(dst
, dst_nritems
+ push_items
);
3298 btrfs_mark_buffer_dirty(src
);
3299 btrfs_mark_buffer_dirty(dst
);
3305 * try to push data from one node into the next node right in the
3308 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
3309 * error, and > 0 if there was no room in the right hand block.
3311 * this will only push up to 1/2 the contents of the left node over
3313 static int balance_node_right(struct btrfs_trans_handle
*trans
,
3314 struct btrfs_root
*root
,
3315 struct extent_buffer
*dst
,
3316 struct extent_buffer
*src
)
3324 WARN_ON(btrfs_header_generation(src
) != trans
->transid
);
3325 WARN_ON(btrfs_header_generation(dst
) != trans
->transid
);
3327 src_nritems
= btrfs_header_nritems(src
);
3328 dst_nritems
= btrfs_header_nritems(dst
);
3329 push_items
= BTRFS_NODEPTRS_PER_BLOCK(root
) - dst_nritems
;
3330 if (push_items
<= 0)
3333 if (src_nritems
< 4)
3336 max_push
= src_nritems
/ 2 + 1;
3337 /* don't try to empty the node */
3338 if (max_push
>= src_nritems
)
3341 if (max_push
< push_items
)
3342 push_items
= max_push
;
3344 tree_mod_log_eb_move(root
->fs_info
, dst
, push_items
, 0, dst_nritems
);
3345 memmove_extent_buffer(dst
, btrfs_node_key_ptr_offset(push_items
),
3346 btrfs_node_key_ptr_offset(0),
3348 sizeof(struct btrfs_key_ptr
));
3350 ret
= tree_mod_log_eb_copy(root
->fs_info
, dst
, src
, 0,
3351 src_nritems
- push_items
, push_items
);
3353 btrfs_abort_transaction(trans
, root
, ret
);
3356 copy_extent_buffer(dst
, src
,
3357 btrfs_node_key_ptr_offset(0),
3358 btrfs_node_key_ptr_offset(src_nritems
- push_items
),
3359 push_items
* sizeof(struct btrfs_key_ptr
));
3361 btrfs_set_header_nritems(src
, src_nritems
- push_items
);
3362 btrfs_set_header_nritems(dst
, dst_nritems
+ push_items
);
3364 btrfs_mark_buffer_dirty(src
);
3365 btrfs_mark_buffer_dirty(dst
);
3371 * helper function to insert a new root level in the tree.
3372 * A new node is allocated, and a single item is inserted to
3373 * point to the existing root
3375 * returns zero on success or < 0 on failure.
3377 static noinline
int insert_new_root(struct btrfs_trans_handle
*trans
,
3378 struct btrfs_root
*root
,
3379 struct btrfs_path
*path
, int level
)
3382 struct extent_buffer
*lower
;
3383 struct extent_buffer
*c
;
3384 struct extent_buffer
*old
;
3385 struct btrfs_disk_key lower_key
;
3387 BUG_ON(path
->nodes
[level
]);
3388 BUG_ON(path
->nodes
[level
-1] != root
->node
);
3390 lower
= path
->nodes
[level
-1];
3392 btrfs_item_key(lower
, &lower_key
, 0);
3394 btrfs_node_key(lower
, &lower_key
, 0);
3396 c
= btrfs_alloc_free_block(trans
, root
, root
->nodesize
, 0,
3397 root
->root_key
.objectid
, &lower_key
,
3398 level
, root
->node
->start
, 0);
3402 root_add_used(root
, root
->nodesize
);
3404 memset_extent_buffer(c
, 0, 0, sizeof(struct btrfs_header
));
3405 btrfs_set_header_nritems(c
, 1);
3406 btrfs_set_header_level(c
, level
);
3407 btrfs_set_header_bytenr(c
, c
->start
);
3408 btrfs_set_header_generation(c
, trans
->transid
);
3409 btrfs_set_header_backref_rev(c
, BTRFS_MIXED_BACKREF_REV
);
3410 btrfs_set_header_owner(c
, root
->root_key
.objectid
);
3412 write_extent_buffer(c
, root
->fs_info
->fsid
, btrfs_header_fsid(),
3415 write_extent_buffer(c
, root
->fs_info
->chunk_tree_uuid
,
3416 btrfs_header_chunk_tree_uuid(c
), BTRFS_UUID_SIZE
);
3418 btrfs_set_node_key(c
, &lower_key
, 0);
3419 btrfs_set_node_blockptr(c
, 0, lower
->start
);
3420 lower_gen
= btrfs_header_generation(lower
);
3421 WARN_ON(lower_gen
!= trans
->transid
);
3423 btrfs_set_node_ptr_generation(c
, 0, lower_gen
);
3425 btrfs_mark_buffer_dirty(c
);
3428 tree_mod_log_set_root_pointer(root
, c
, 0);
3429 rcu_assign_pointer(root
->node
, c
);
3431 /* the super has an extra ref to root->node */
3432 free_extent_buffer(old
);
3434 add_root_to_dirty_list(root
);
3435 extent_buffer_get(c
);
3436 path
->nodes
[level
] = c
;
3437 path
->locks
[level
] = BTRFS_WRITE_LOCK
;
3438 path
->slots
[level
] = 0;
3443 * worker function to insert a single pointer in a node.
3444 * the node should have enough room for the pointer already
3446 * slot and level indicate where you want the key to go, and
3447 * blocknr is the block the key points to.
3449 static void insert_ptr(struct btrfs_trans_handle
*trans
,
3450 struct btrfs_root
*root
, struct btrfs_path
*path
,
3451 struct btrfs_disk_key
*key
, u64 bytenr
,
3452 int slot
, int level
)
3454 struct extent_buffer
*lower
;
3458 BUG_ON(!path
->nodes
[level
]);
3459 btrfs_assert_tree_locked(path
->nodes
[level
]);
3460 lower
= path
->nodes
[level
];
3461 nritems
= btrfs_header_nritems(lower
);
3462 BUG_ON(slot
> nritems
);
3463 BUG_ON(nritems
== BTRFS_NODEPTRS_PER_BLOCK(root
));
3464 if (slot
!= nritems
) {
3466 tree_mod_log_eb_move(root
->fs_info
, lower
, slot
+ 1,
3467 slot
, nritems
- slot
);
3468 memmove_extent_buffer(lower
,
3469 btrfs_node_key_ptr_offset(slot
+ 1),
3470 btrfs_node_key_ptr_offset(slot
),
3471 (nritems
- slot
) * sizeof(struct btrfs_key_ptr
));
3474 ret
= tree_mod_log_insert_key(root
->fs_info
, lower
, slot
,
3475 MOD_LOG_KEY_ADD
, GFP_NOFS
);
3478 btrfs_set_node_key(lower
, key
, slot
);
3479 btrfs_set_node_blockptr(lower
, slot
, bytenr
);
3480 WARN_ON(trans
->transid
== 0);
3481 btrfs_set_node_ptr_generation(lower
, slot
, trans
->transid
);
3482 btrfs_set_header_nritems(lower
, nritems
+ 1);
3483 btrfs_mark_buffer_dirty(lower
);
3487 * split the node at the specified level in path in two.
3488 * The path is corrected to point to the appropriate node after the split
3490 * Before splitting this tries to make some room in the node by pushing
3491 * left and right, if either one works, it returns right away.
3493 * returns 0 on success and < 0 on failure
3495 static noinline
int split_node(struct btrfs_trans_handle
*trans
,
3496 struct btrfs_root
*root
,
3497 struct btrfs_path
*path
, int level
)
3499 struct extent_buffer
*c
;
3500 struct extent_buffer
*split
;
3501 struct btrfs_disk_key disk_key
;
3506 c
= path
->nodes
[level
];
3507 WARN_ON(btrfs_header_generation(c
) != trans
->transid
);
3508 if (c
== root
->node
) {
3510 * trying to split the root, lets make a new one
3512 * tree mod log: We don't log_removal old root in
3513 * insert_new_root, because that root buffer will be kept as a
3514 * normal node. We are going to log removal of half of the
3515 * elements below with tree_mod_log_eb_copy. We're holding a
3516 * tree lock on the buffer, which is why we cannot race with
3517 * other tree_mod_log users.
3519 ret
= insert_new_root(trans
, root
, path
, level
+ 1);
3523 ret
= push_nodes_for_insert(trans
, root
, path
, level
);
3524 c
= path
->nodes
[level
];
3525 if (!ret
&& btrfs_header_nritems(c
) <
3526 BTRFS_NODEPTRS_PER_BLOCK(root
) - 3)
3532 c_nritems
= btrfs_header_nritems(c
);
3533 mid
= (c_nritems
+ 1) / 2;
3534 btrfs_node_key(c
, &disk_key
, mid
);
3536 split
= btrfs_alloc_free_block(trans
, root
, root
->nodesize
, 0,
3537 root
->root_key
.objectid
,
3538 &disk_key
, level
, c
->start
, 0);
3540 return PTR_ERR(split
);
3542 root_add_used(root
, root
->nodesize
);
3544 memset_extent_buffer(split
, 0, 0, sizeof(struct btrfs_header
));
3545 btrfs_set_header_level(split
, btrfs_header_level(c
));
3546 btrfs_set_header_bytenr(split
, split
->start
);
3547 btrfs_set_header_generation(split
, trans
->transid
);
3548 btrfs_set_header_backref_rev(split
, BTRFS_MIXED_BACKREF_REV
);
3549 btrfs_set_header_owner(split
, root
->root_key
.objectid
);
3550 write_extent_buffer(split
, root
->fs_info
->fsid
,
3551 btrfs_header_fsid(), BTRFS_FSID_SIZE
);
3552 write_extent_buffer(split
, root
->fs_info
->chunk_tree_uuid
,
3553 btrfs_header_chunk_tree_uuid(split
),
3556 ret
= tree_mod_log_eb_copy(root
->fs_info
, split
, c
, 0,
3557 mid
, c_nritems
- mid
);
3559 btrfs_abort_transaction(trans
, root
, ret
);
3562 copy_extent_buffer(split
, c
,
3563 btrfs_node_key_ptr_offset(0),
3564 btrfs_node_key_ptr_offset(mid
),
3565 (c_nritems
- mid
) * sizeof(struct btrfs_key_ptr
));
3566 btrfs_set_header_nritems(split
, c_nritems
- mid
);
3567 btrfs_set_header_nritems(c
, mid
);
3570 btrfs_mark_buffer_dirty(c
);
3571 btrfs_mark_buffer_dirty(split
);
3573 insert_ptr(trans
, root
, path
, &disk_key
, split
->start
,
3574 path
->slots
[level
+ 1] + 1, level
+ 1);
3576 if (path
->slots
[level
] >= mid
) {
3577 path
->slots
[level
] -= mid
;
3578 btrfs_tree_unlock(c
);
3579 free_extent_buffer(c
);
3580 path
->nodes
[level
] = split
;
3581 path
->slots
[level
+ 1] += 1;
3583 btrfs_tree_unlock(split
);
3584 free_extent_buffer(split
);
3590 * how many bytes are required to store the items in a leaf. start
3591 * and nr indicate which items in the leaf to check. This totals up the
3592 * space used both by the item structs and the item data
3594 static int leaf_space_used(struct extent_buffer
*l
, int start
, int nr
)
3596 struct btrfs_item
*start_item
;
3597 struct btrfs_item
*end_item
;
3598 struct btrfs_map_token token
;
3600 int nritems
= btrfs_header_nritems(l
);
3601 int end
= min(nritems
, start
+ nr
) - 1;
3605 btrfs_init_map_token(&token
);
3606 start_item
= btrfs_item_nr(start
);
3607 end_item
= btrfs_item_nr(end
);
3608 data_len
= btrfs_token_item_offset(l
, start_item
, &token
) +
3609 btrfs_token_item_size(l
, start_item
, &token
);
3610 data_len
= data_len
- btrfs_token_item_offset(l
, end_item
, &token
);
3611 data_len
+= sizeof(struct btrfs_item
) * nr
;
3612 WARN_ON(data_len
< 0);
3617 * The space between the end of the leaf items and
3618 * the start of the leaf data. IOW, how much room
3619 * the leaf has left for both items and data
3621 noinline
int btrfs_leaf_free_space(struct btrfs_root
*root
,
3622 struct extent_buffer
*leaf
)
3624 int nritems
= btrfs_header_nritems(leaf
);
3626 ret
= BTRFS_LEAF_DATA_SIZE(root
) - leaf_space_used(leaf
, 0, nritems
);
3628 btrfs_crit(root
->fs_info
,
3629 "leaf free space ret %d, leaf data size %lu, used %d nritems %d",
3630 ret
, (unsigned long) BTRFS_LEAF_DATA_SIZE(root
),
3631 leaf_space_used(leaf
, 0, nritems
), nritems
);
3637 * min slot controls the lowest index we're willing to push to the
3638 * right. We'll push up to and including min_slot, but no lower
3640 static noinline
int __push_leaf_right(struct btrfs_trans_handle
*trans
,
3641 struct btrfs_root
*root
,
3642 struct btrfs_path
*path
,
3643 int data_size
, int empty
,
3644 struct extent_buffer
*right
,
3645 int free_space
, u32 left_nritems
,
3648 struct extent_buffer
*left
= path
->nodes
[0];
3649 struct extent_buffer
*upper
= path
->nodes
[1];
3650 struct btrfs_map_token token
;
3651 struct btrfs_disk_key disk_key
;
3656 struct btrfs_item
*item
;
3662 btrfs_init_map_token(&token
);
3667 nr
= max_t(u32
, 1, min_slot
);
3669 if (path
->slots
[0] >= left_nritems
)
3670 push_space
+= data_size
;
3672 slot
= path
->slots
[1];
3673 i
= left_nritems
- 1;
3675 item
= btrfs_item_nr(i
);
3677 if (!empty
&& push_items
> 0) {
3678 if (path
->slots
[0] > i
)
3680 if (path
->slots
[0] == i
) {
3681 int space
= btrfs_leaf_free_space(root
, left
);
3682 if (space
+ push_space
* 2 > free_space
)
3687 if (path
->slots
[0] == i
)
3688 push_space
+= data_size
;
3690 this_item_size
= btrfs_item_size(left
, item
);
3691 if (this_item_size
+ sizeof(*item
) + push_space
> free_space
)
3695 push_space
+= this_item_size
+ sizeof(*item
);
3701 if (push_items
== 0)
3704 WARN_ON(!empty
&& push_items
== left_nritems
);
3706 /* push left to right */
3707 right_nritems
= btrfs_header_nritems(right
);
3709 push_space
= btrfs_item_end_nr(left
, left_nritems
- push_items
);
3710 push_space
-= leaf_data_end(root
, left
);
3712 /* make room in the right data area */
3713 data_end
= leaf_data_end(root
, right
);
3714 memmove_extent_buffer(right
,
3715 btrfs_leaf_data(right
) + data_end
- push_space
,
3716 btrfs_leaf_data(right
) + data_end
,
3717 BTRFS_LEAF_DATA_SIZE(root
) - data_end
);
3719 /* copy from the left data area */
3720 copy_extent_buffer(right
, left
, btrfs_leaf_data(right
) +
3721 BTRFS_LEAF_DATA_SIZE(root
) - push_space
,
3722 btrfs_leaf_data(left
) + leaf_data_end(root
, left
),
3725 memmove_extent_buffer(right
, btrfs_item_nr_offset(push_items
),
3726 btrfs_item_nr_offset(0),
3727 right_nritems
* sizeof(struct btrfs_item
));
3729 /* copy the items from left to right */
3730 copy_extent_buffer(right
, left
, btrfs_item_nr_offset(0),
3731 btrfs_item_nr_offset(left_nritems
- push_items
),
3732 push_items
* sizeof(struct btrfs_item
));
3734 /* update the item pointers */
3735 right_nritems
+= push_items
;
3736 btrfs_set_header_nritems(right
, right_nritems
);
3737 push_space
= BTRFS_LEAF_DATA_SIZE(root
);
3738 for (i
= 0; i
< right_nritems
; i
++) {
3739 item
= btrfs_item_nr(i
);
3740 push_space
-= btrfs_token_item_size(right
, item
, &token
);
3741 btrfs_set_token_item_offset(right
, item
, push_space
, &token
);
3744 left_nritems
-= push_items
;
3745 btrfs_set_header_nritems(left
, left_nritems
);
3748 btrfs_mark_buffer_dirty(left
);
3750 clean_tree_block(trans
, root
, left
);
3752 btrfs_mark_buffer_dirty(right
);
3754 btrfs_item_key(right
, &disk_key
, 0);
3755 btrfs_set_node_key(upper
, &disk_key
, slot
+ 1);
3756 btrfs_mark_buffer_dirty(upper
);
3758 /* then fixup the leaf pointer in the path */
3759 if (path
->slots
[0] >= left_nritems
) {
3760 path
->slots
[0] -= left_nritems
;
3761 if (btrfs_header_nritems(path
->nodes
[0]) == 0)
3762 clean_tree_block(trans
, root
, path
->nodes
[0]);
3763 btrfs_tree_unlock(path
->nodes
[0]);
3764 free_extent_buffer(path
->nodes
[0]);
3765 path
->nodes
[0] = right
;
3766 path
->slots
[1] += 1;
3768 btrfs_tree_unlock(right
);
3769 free_extent_buffer(right
);
3774 btrfs_tree_unlock(right
);
3775 free_extent_buffer(right
);
3780 * push some data in the path leaf to the right, trying to free up at
3781 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3783 * returns 1 if the push failed because the other node didn't have enough
3784 * room, 0 if everything worked out and < 0 if there were major errors.
3786 * this will push starting from min_slot to the end of the leaf. It won't
3787 * push any slot lower than min_slot
3789 static int push_leaf_right(struct btrfs_trans_handle
*trans
, struct btrfs_root
3790 *root
, struct btrfs_path
*path
,
3791 int min_data_size
, int data_size
,
3792 int empty
, u32 min_slot
)
3794 struct extent_buffer
*left
= path
->nodes
[0];
3795 struct extent_buffer
*right
;
3796 struct extent_buffer
*upper
;
3802 if (!path
->nodes
[1])
3805 slot
= path
->slots
[1];
3806 upper
= path
->nodes
[1];
3807 if (slot
>= btrfs_header_nritems(upper
) - 1)
3810 btrfs_assert_tree_locked(path
->nodes
[1]);
3812 right
= read_node_slot(root
, upper
, slot
+ 1);
3816 btrfs_tree_lock(right
);
3817 btrfs_set_lock_blocking(right
);
3819 free_space
= btrfs_leaf_free_space(root
, right
);
3820 if (free_space
< data_size
)
3823 /* cow and double check */
3824 ret
= btrfs_cow_block(trans
, root
, right
, upper
,
3829 free_space
= btrfs_leaf_free_space(root
, right
);
3830 if (free_space
< data_size
)
3833 left_nritems
= btrfs_header_nritems(left
);
3834 if (left_nritems
== 0)
3837 if (path
->slots
[0] == left_nritems
&& !empty
) {
3838 /* Key greater than all keys in the leaf, right neighbor has
3839 * enough room for it and we're not emptying our leaf to delete
3840 * it, therefore use right neighbor to insert the new item and
3841 * no need to touch/dirty our left leaft. */
3842 btrfs_tree_unlock(left
);
3843 free_extent_buffer(left
);
3844 path
->nodes
[0] = right
;
3850 return __push_leaf_right(trans
, root
, path
, min_data_size
, empty
,
3851 right
, free_space
, left_nritems
, min_slot
);
3853 btrfs_tree_unlock(right
);
3854 free_extent_buffer(right
);
3859 * push some data in the path leaf to the left, trying to free up at
3860 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3862 * max_slot can put a limit on how far into the leaf we'll push items. The
3863 * item at 'max_slot' won't be touched. Use (u32)-1 to make us do all the
3866 static noinline
int __push_leaf_left(struct btrfs_trans_handle
*trans
,
3867 struct btrfs_root
*root
,
3868 struct btrfs_path
*path
, int data_size
,
3869 int empty
, struct extent_buffer
*left
,
3870 int free_space
, u32 right_nritems
,
3873 struct btrfs_disk_key disk_key
;
3874 struct extent_buffer
*right
= path
->nodes
[0];
3878 struct btrfs_item
*item
;
3879 u32 old_left_nritems
;
3883 u32 old_left_item_size
;
3884 struct btrfs_map_token token
;
3886 btrfs_init_map_token(&token
);
3889 nr
= min(right_nritems
, max_slot
);
3891 nr
= min(right_nritems
- 1, max_slot
);
3893 for (i
= 0; i
< nr
; i
++) {
3894 item
= btrfs_item_nr(i
);
3896 if (!empty
&& push_items
> 0) {
3897 if (path
->slots
[0] < i
)
3899 if (path
->slots
[0] == i
) {
3900 int space
= btrfs_leaf_free_space(root
, right
);
3901 if (space
+ push_space
* 2 > free_space
)
3906 if (path
->slots
[0] == i
)
3907 push_space
+= data_size
;
3909 this_item_size
= btrfs_item_size(right
, item
);
3910 if (this_item_size
+ sizeof(*item
) + push_space
> free_space
)
3914 push_space
+= this_item_size
+ sizeof(*item
);
3917 if (push_items
== 0) {
3921 WARN_ON(!empty
&& push_items
== btrfs_header_nritems(right
));
3923 /* push data from right to left */
3924 copy_extent_buffer(left
, right
,
3925 btrfs_item_nr_offset(btrfs_header_nritems(left
)),
3926 btrfs_item_nr_offset(0),
3927 push_items
* sizeof(struct btrfs_item
));
3929 push_space
= BTRFS_LEAF_DATA_SIZE(root
) -
3930 btrfs_item_offset_nr(right
, push_items
- 1);
3932 copy_extent_buffer(left
, right
, btrfs_leaf_data(left
) +
3933 leaf_data_end(root
, left
) - push_space
,
3934 btrfs_leaf_data(right
) +
3935 btrfs_item_offset_nr(right
, push_items
- 1),
3937 old_left_nritems
= btrfs_header_nritems(left
);
3938 BUG_ON(old_left_nritems
<= 0);
3940 old_left_item_size
= btrfs_item_offset_nr(left
, old_left_nritems
- 1);
3941 for (i
= old_left_nritems
; i
< old_left_nritems
+ push_items
; i
++) {
3944 item
= btrfs_item_nr(i
);
3946 ioff
= btrfs_token_item_offset(left
, item
, &token
);
3947 btrfs_set_token_item_offset(left
, item
,
3948 ioff
- (BTRFS_LEAF_DATA_SIZE(root
) - old_left_item_size
),
3951 btrfs_set_header_nritems(left
, old_left_nritems
+ push_items
);
3953 /* fixup right node */
3954 if (push_items
> right_nritems
)
3955 WARN(1, KERN_CRIT
"push items %d nr %u\n", push_items
,
3958 if (push_items
< right_nritems
) {
3959 push_space
= btrfs_item_offset_nr(right
, push_items
- 1) -
3960 leaf_data_end(root
, right
);
3961 memmove_extent_buffer(right
, btrfs_leaf_data(right
) +
3962 BTRFS_LEAF_DATA_SIZE(root
) - push_space
,
3963 btrfs_leaf_data(right
) +
3964 leaf_data_end(root
, right
), push_space
);
3966 memmove_extent_buffer(right
, btrfs_item_nr_offset(0),
3967 btrfs_item_nr_offset(push_items
),
3968 (btrfs_header_nritems(right
) - push_items
) *
3969 sizeof(struct btrfs_item
));
3971 right_nritems
-= push_items
;
3972 btrfs_set_header_nritems(right
, right_nritems
);
3973 push_space
= BTRFS_LEAF_DATA_SIZE(root
);
3974 for (i
= 0; i
< right_nritems
; i
++) {
3975 item
= btrfs_item_nr(i
);
3977 push_space
= push_space
- btrfs_token_item_size(right
,
3979 btrfs_set_token_item_offset(right
, item
, push_space
, &token
);
3982 btrfs_mark_buffer_dirty(left
);
3984 btrfs_mark_buffer_dirty(right
);
3986 clean_tree_block(trans
, root
, right
);
3988 btrfs_item_key(right
, &disk_key
, 0);
3989 fixup_low_keys(root
, path
, &disk_key
, 1);
3991 /* then fixup the leaf pointer in the path */
3992 if (path
->slots
[0] < push_items
) {
3993 path
->slots
[0] += old_left_nritems
;
3994 btrfs_tree_unlock(path
->nodes
[0]);
3995 free_extent_buffer(path
->nodes
[0]);
3996 path
->nodes
[0] = left
;
3997 path
->slots
[1] -= 1;
3999 btrfs_tree_unlock(left
);
4000 free_extent_buffer(left
);
4001 path
->slots
[0] -= push_items
;
4003 BUG_ON(path
->slots
[0] < 0);
4006 btrfs_tree_unlock(left
);
4007 free_extent_buffer(left
);
4012 * push some data in the path leaf to the left, trying to free up at
4013 * least data_size bytes. returns zero if the push worked, nonzero otherwise
4015 * max_slot can put a limit on how far into the leaf we'll push items. The
4016 * item at 'max_slot' won't be touched. Use (u32)-1 to make us push all the
4019 static int push_leaf_left(struct btrfs_trans_handle
*trans
, struct btrfs_root
4020 *root
, struct btrfs_path
*path
, int min_data_size
,
4021 int data_size
, int empty
, u32 max_slot
)
4023 struct extent_buffer
*right
= path
->nodes
[0];
4024 struct extent_buffer
*left
;
4030 slot
= path
->slots
[1];
4033 if (!path
->nodes
[1])
4036 right_nritems
= btrfs_header_nritems(right
);
4037 if (right_nritems
== 0)
4040 btrfs_assert_tree_locked(path
->nodes
[1]);
4042 left
= read_node_slot(root
, path
->nodes
[1], slot
- 1);
4046 btrfs_tree_lock(left
);
4047 btrfs_set_lock_blocking(left
);
4049 free_space
= btrfs_leaf_free_space(root
, left
);
4050 if (free_space
< data_size
) {
4055 /* cow and double check */
4056 ret
= btrfs_cow_block(trans
, root
, left
,
4057 path
->nodes
[1], slot
- 1, &left
);
4059 /* we hit -ENOSPC, but it isn't fatal here */
4065 free_space
= btrfs_leaf_free_space(root
, left
);
4066 if (free_space
< data_size
) {
4071 return __push_leaf_left(trans
, root
, path
, min_data_size
,
4072 empty
, left
, free_space
, right_nritems
,
4075 btrfs_tree_unlock(left
);
4076 free_extent_buffer(left
);
4081 * split the path's leaf in two, making sure there is at least data_size
4082 * available for the resulting leaf level of the path.
4084 static noinline
void copy_for_split(struct btrfs_trans_handle
*trans
,
4085 struct btrfs_root
*root
,
4086 struct btrfs_path
*path
,
4087 struct extent_buffer
*l
,
4088 struct extent_buffer
*right
,
4089 int slot
, int mid
, int nritems
)
4094 struct btrfs_disk_key disk_key
;
4095 struct btrfs_map_token token
;
4097 btrfs_init_map_token(&token
);
4099 nritems
= nritems
- mid
;
4100 btrfs_set_header_nritems(right
, nritems
);
4101 data_copy_size
= btrfs_item_end_nr(l
, mid
) - leaf_data_end(root
, l
);
4103 copy_extent_buffer(right
, l
, btrfs_item_nr_offset(0),
4104 btrfs_item_nr_offset(mid
),
4105 nritems
* sizeof(struct btrfs_item
));
4107 copy_extent_buffer(right
, l
,
4108 btrfs_leaf_data(right
) + BTRFS_LEAF_DATA_SIZE(root
) -
4109 data_copy_size
, btrfs_leaf_data(l
) +
4110 leaf_data_end(root
, l
), data_copy_size
);
4112 rt_data_off
= BTRFS_LEAF_DATA_SIZE(root
) -
4113 btrfs_item_end_nr(l
, mid
);
4115 for (i
= 0; i
< nritems
; i
++) {
4116 struct btrfs_item
*item
= btrfs_item_nr(i
);
4119 ioff
= btrfs_token_item_offset(right
, item
, &token
);
4120 btrfs_set_token_item_offset(right
, item
,
4121 ioff
+ rt_data_off
, &token
);
4124 btrfs_set_header_nritems(l
, mid
);
4125 btrfs_item_key(right
, &disk_key
, 0);
4126 insert_ptr(trans
, root
, path
, &disk_key
, right
->start
,
4127 path
->slots
[1] + 1, 1);
4129 btrfs_mark_buffer_dirty(right
);
4130 btrfs_mark_buffer_dirty(l
);
4131 BUG_ON(path
->slots
[0] != slot
);
4134 btrfs_tree_unlock(path
->nodes
[0]);
4135 free_extent_buffer(path
->nodes
[0]);
4136 path
->nodes
[0] = right
;
4137 path
->slots
[0] -= mid
;
4138 path
->slots
[1] += 1;
4140 btrfs_tree_unlock(right
);
4141 free_extent_buffer(right
);
4144 BUG_ON(path
->slots
[0] < 0);
4148 * double splits happen when we need to insert a big item in the middle
4149 * of a leaf. A double split can leave us with 3 mostly empty leaves:
4150 * leaf: [ slots 0 - N] [ our target ] [ N + 1 - total in leaf ]
4153 * We avoid this by trying to push the items on either side of our target
4154 * into the adjacent leaves. If all goes well we can avoid the double split
4157 static noinline
int push_for_double_split(struct btrfs_trans_handle
*trans
,
4158 struct btrfs_root
*root
,
4159 struct btrfs_path
*path
,
4166 int space_needed
= data_size
;
4168 slot
= path
->slots
[0];
4169 if (slot
< btrfs_header_nritems(path
->nodes
[0]))
4170 space_needed
-= btrfs_leaf_free_space(root
, path
->nodes
[0]);
4173 * try to push all the items after our slot into the
4176 ret
= push_leaf_right(trans
, root
, path
, 1, space_needed
, 0, slot
);
4183 nritems
= btrfs_header_nritems(path
->nodes
[0]);
4185 * our goal is to get our slot at the start or end of a leaf. If
4186 * we've done so we're done
4188 if (path
->slots
[0] == 0 || path
->slots
[0] == nritems
)
4191 if (btrfs_leaf_free_space(root
, path
->nodes
[0]) >= data_size
)
4194 /* try to push all the items before our slot into the next leaf */
4195 slot
= path
->slots
[0];
4196 ret
= push_leaf_left(trans
, root
, path
, 1, space_needed
, 0, slot
);
4209 * split the path's leaf in two, making sure there is at least data_size
4210 * available for the resulting leaf level of the path.
4212 * returns 0 if all went well and < 0 on failure.
4214 static noinline
int split_leaf(struct btrfs_trans_handle
*trans
,
4215 struct btrfs_root
*root
,
4216 struct btrfs_key
*ins_key
,
4217 struct btrfs_path
*path
, int data_size
,
4220 struct btrfs_disk_key disk_key
;
4221 struct extent_buffer
*l
;
4225 struct extent_buffer
*right
;
4229 int num_doubles
= 0;
4230 int tried_avoid_double
= 0;
4233 slot
= path
->slots
[0];
4234 if (extend
&& data_size
+ btrfs_item_size_nr(l
, slot
) +
4235 sizeof(struct btrfs_item
) > BTRFS_LEAF_DATA_SIZE(root
))
4238 /* first try to make some room by pushing left and right */
4239 if (data_size
&& path
->nodes
[1]) {
4240 int space_needed
= data_size
;
4242 if (slot
< btrfs_header_nritems(l
))
4243 space_needed
-= btrfs_leaf_free_space(root
, l
);
4245 wret
= push_leaf_right(trans
, root
, path
, space_needed
,
4246 space_needed
, 0, 0);
4250 wret
= push_leaf_left(trans
, root
, path
, space_needed
,
4251 space_needed
, 0, (u32
)-1);
4257 /* did the pushes work? */
4258 if (btrfs_leaf_free_space(root
, l
) >= data_size
)
4262 if (!path
->nodes
[1]) {
4263 ret
= insert_new_root(trans
, root
, path
, 1);
4270 slot
= path
->slots
[0];
4271 nritems
= btrfs_header_nritems(l
);
4272 mid
= (nritems
+ 1) / 2;
4276 leaf_space_used(l
, mid
, nritems
- mid
) + data_size
>
4277 BTRFS_LEAF_DATA_SIZE(root
)) {
4278 if (slot
>= nritems
) {
4282 if (mid
!= nritems
&&
4283 leaf_space_used(l
, mid
, nritems
- mid
) +
4284 data_size
> BTRFS_LEAF_DATA_SIZE(root
)) {
4285 if (data_size
&& !tried_avoid_double
)
4286 goto push_for_double
;
4292 if (leaf_space_used(l
, 0, mid
) + data_size
>
4293 BTRFS_LEAF_DATA_SIZE(root
)) {
4294 if (!extend
&& data_size
&& slot
== 0) {
4296 } else if ((extend
|| !data_size
) && slot
== 0) {
4300 if (mid
!= nritems
&&
4301 leaf_space_used(l
, mid
, nritems
- mid
) +
4302 data_size
> BTRFS_LEAF_DATA_SIZE(root
)) {
4303 if (data_size
&& !tried_avoid_double
)
4304 goto push_for_double
;
4312 btrfs_cpu_key_to_disk(&disk_key
, ins_key
);
4314 btrfs_item_key(l
, &disk_key
, mid
);
4316 right
= btrfs_alloc_free_block(trans
, root
, root
->leafsize
, 0,
4317 root
->root_key
.objectid
,
4318 &disk_key
, 0, l
->start
, 0);
4320 return PTR_ERR(right
);
4322 root_add_used(root
, root
->leafsize
);
4324 memset_extent_buffer(right
, 0, 0, sizeof(struct btrfs_header
));
4325 btrfs_set_header_bytenr(right
, right
->start
);
4326 btrfs_set_header_generation(right
, trans
->transid
);
4327 btrfs_set_header_backref_rev(right
, BTRFS_MIXED_BACKREF_REV
);
4328 btrfs_set_header_owner(right
, root
->root_key
.objectid
);
4329 btrfs_set_header_level(right
, 0);
4330 write_extent_buffer(right
, root
->fs_info
->fsid
,
4331 btrfs_header_fsid(), BTRFS_FSID_SIZE
);
4333 write_extent_buffer(right
, root
->fs_info
->chunk_tree_uuid
,
4334 btrfs_header_chunk_tree_uuid(right
),
4339 btrfs_set_header_nritems(right
, 0);
4340 insert_ptr(trans
, root
, path
, &disk_key
, right
->start
,
4341 path
->slots
[1] + 1, 1);
4342 btrfs_tree_unlock(path
->nodes
[0]);
4343 free_extent_buffer(path
->nodes
[0]);
4344 path
->nodes
[0] = right
;
4346 path
->slots
[1] += 1;
4348 btrfs_set_header_nritems(right
, 0);
4349 insert_ptr(trans
, root
, path
, &disk_key
, right
->start
,
4351 btrfs_tree_unlock(path
->nodes
[0]);
4352 free_extent_buffer(path
->nodes
[0]);
4353 path
->nodes
[0] = right
;
4355 if (path
->slots
[1] == 0)
4356 fixup_low_keys(root
, path
, &disk_key
, 1);
4358 btrfs_mark_buffer_dirty(right
);
4362 copy_for_split(trans
, root
, path
, l
, right
, slot
, mid
, nritems
);
4365 BUG_ON(num_doubles
!= 0);
4373 push_for_double_split(trans
, root
, path
, data_size
);
4374 tried_avoid_double
= 1;
4375 if (btrfs_leaf_free_space(root
, path
->nodes
[0]) >= data_size
)
4380 static noinline
int setup_leaf_for_split(struct btrfs_trans_handle
*trans
,
4381 struct btrfs_root
*root
,
4382 struct btrfs_path
*path
, int ins_len
)
4384 struct btrfs_key key
;
4385 struct extent_buffer
*leaf
;
4386 struct btrfs_file_extent_item
*fi
;
4391 leaf
= path
->nodes
[0];
4392 btrfs_item_key_to_cpu(leaf
, &key
, path
->slots
[0]);
4394 BUG_ON(key
.type
!= BTRFS_EXTENT_DATA_KEY
&&
4395 key
.type
!= BTRFS_EXTENT_CSUM_KEY
);
4397 if (btrfs_leaf_free_space(root
, leaf
) >= ins_len
)
4400 item_size
= btrfs_item_size_nr(leaf
, path
->slots
[0]);
4401 if (key
.type
== BTRFS_EXTENT_DATA_KEY
) {
4402 fi
= btrfs_item_ptr(leaf
, path
->slots
[0],
4403 struct btrfs_file_extent_item
);
4404 extent_len
= btrfs_file_extent_num_bytes(leaf
, fi
);
4406 btrfs_release_path(path
);
4408 path
->keep_locks
= 1;
4409 path
->search_for_split
= 1;
4410 ret
= btrfs_search_slot(trans
, root
, &key
, path
, 0, 1);
4411 path
->search_for_split
= 0;
4416 leaf
= path
->nodes
[0];
4417 /* if our item isn't there or got smaller, return now */
4418 if (ret
> 0 || item_size
!= btrfs_item_size_nr(leaf
, path
->slots
[0]))
4421 /* the leaf has changed, it now has room. return now */
4422 if (btrfs_leaf_free_space(root
, path
->nodes
[0]) >= ins_len
)
4425 if (key
.type
== BTRFS_EXTENT_DATA_KEY
) {
4426 fi
= btrfs_item_ptr(leaf
, path
->slots
[0],
4427 struct btrfs_file_extent_item
);
4428 if (extent_len
!= btrfs_file_extent_num_bytes(leaf
, fi
))
4432 btrfs_set_path_blocking(path
);
4433 ret
= split_leaf(trans
, root
, &key
, path
, ins_len
, 1);
4437 path
->keep_locks
= 0;
4438 btrfs_unlock_up_safe(path
, 1);
4441 path
->keep_locks
= 0;
4445 static noinline
int split_item(struct btrfs_trans_handle
*trans
,
4446 struct btrfs_root
*root
,
4447 struct btrfs_path
*path
,
4448 struct btrfs_key
*new_key
,
4449 unsigned long split_offset
)
4451 struct extent_buffer
*leaf
;
4452 struct btrfs_item
*item
;
4453 struct btrfs_item
*new_item
;
4459 struct btrfs_disk_key disk_key
;
4461 leaf
= path
->nodes
[0];
4462 BUG_ON(btrfs_leaf_free_space(root
, leaf
) < sizeof(struct btrfs_item
));
4464 btrfs_set_path_blocking(path
);
4466 item
= btrfs_item_nr(path
->slots
[0]);
4467 orig_offset
= btrfs_item_offset(leaf
, item
);
4468 item_size
= btrfs_item_size(leaf
, item
);
4470 buf
= kmalloc(item_size
, GFP_NOFS
);
4474 read_extent_buffer(leaf
, buf
, btrfs_item_ptr_offset(leaf
,
4475 path
->slots
[0]), item_size
);
4477 slot
= path
->slots
[0] + 1;
4478 nritems
= btrfs_header_nritems(leaf
);
4479 if (slot
!= nritems
) {
4480 /* shift the items */
4481 memmove_extent_buffer(leaf
, btrfs_item_nr_offset(slot
+ 1),
4482 btrfs_item_nr_offset(slot
),
4483 (nritems
- slot
) * sizeof(struct btrfs_item
));
4486 btrfs_cpu_key_to_disk(&disk_key
, new_key
);
4487 btrfs_set_item_key(leaf
, &disk_key
, slot
);
4489 new_item
= btrfs_item_nr(slot
);
4491 btrfs_set_item_offset(leaf
, new_item
, orig_offset
);
4492 btrfs_set_item_size(leaf
, new_item
, item_size
- split_offset
);
4494 btrfs_set_item_offset(leaf
, item
,
4495 orig_offset
+ item_size
- split_offset
);
4496 btrfs_set_item_size(leaf
, item
, split_offset
);
4498 btrfs_set_header_nritems(leaf
, nritems
+ 1);
4500 /* write the data for the start of the original item */
4501 write_extent_buffer(leaf
, buf
,
4502 btrfs_item_ptr_offset(leaf
, path
->slots
[0]),
4505 /* write the data for the new item */
4506 write_extent_buffer(leaf
, buf
+ split_offset
,
4507 btrfs_item_ptr_offset(leaf
, slot
),
4508 item_size
- split_offset
);
4509 btrfs_mark_buffer_dirty(leaf
);
4511 BUG_ON(btrfs_leaf_free_space(root
, leaf
) < 0);
4517 * This function splits a single item into two items,
4518 * giving 'new_key' to the new item and splitting the
4519 * old one at split_offset (from the start of the item).
4521 * The path may be released by this operation. After
4522 * the split, the path is pointing to the old item. The
4523 * new item is going to be in the same node as the old one.
4525 * Note, the item being split must be smaller enough to live alone on
4526 * a tree block with room for one extra struct btrfs_item
4528 * This allows us to split the item in place, keeping a lock on the
4529 * leaf the entire time.
4531 int btrfs_split_item(struct btrfs_trans_handle
*trans
,
4532 struct btrfs_root
*root
,
4533 struct btrfs_path
*path
,
4534 struct btrfs_key
*new_key
,
4535 unsigned long split_offset
)
4538 ret
= setup_leaf_for_split(trans
, root
, path
,
4539 sizeof(struct btrfs_item
));
4543 ret
= split_item(trans
, root
, path
, new_key
, split_offset
);
4548 * This function duplicate a item, giving 'new_key' to the new item.
4549 * It guarantees both items live in the same tree leaf and the new item
4550 * is contiguous with the original item.
4552 * This allows us to split file extent in place, keeping a lock on the
4553 * leaf the entire time.
4555 int btrfs_duplicate_item(struct btrfs_trans_handle
*trans
,
4556 struct btrfs_root
*root
,
4557 struct btrfs_path
*path
,
4558 struct btrfs_key
*new_key
)
4560 struct extent_buffer
*leaf
;
4564 leaf
= path
->nodes
[0];
4565 item_size
= btrfs_item_size_nr(leaf
, path
->slots
[0]);
4566 ret
= setup_leaf_for_split(trans
, root
, path
,
4567 item_size
+ sizeof(struct btrfs_item
));
4572 setup_items_for_insert(root
, path
, new_key
, &item_size
,
4573 item_size
, item_size
+
4574 sizeof(struct btrfs_item
), 1);
4575 leaf
= path
->nodes
[0];
4576 memcpy_extent_buffer(leaf
,
4577 btrfs_item_ptr_offset(leaf
, path
->slots
[0]),
4578 btrfs_item_ptr_offset(leaf
, path
->slots
[0] - 1),
4584 * make the item pointed to by the path smaller. new_size indicates
4585 * how small to make it, and from_end tells us if we just chop bytes
4586 * off the end of the item or if we shift the item to chop bytes off
4589 void btrfs_truncate_item(struct btrfs_root
*root
, struct btrfs_path
*path
,
4590 u32 new_size
, int from_end
)
4593 struct extent_buffer
*leaf
;
4594 struct btrfs_item
*item
;
4596 unsigned int data_end
;
4597 unsigned int old_data_start
;
4598 unsigned int old_size
;
4599 unsigned int size_diff
;
4601 struct btrfs_map_token token
;
4603 btrfs_init_map_token(&token
);
4605 leaf
= path
->nodes
[0];
4606 slot
= path
->slots
[0];
4608 old_size
= btrfs_item_size_nr(leaf
, slot
);
4609 if (old_size
== new_size
)
4612 nritems
= btrfs_header_nritems(leaf
);
4613 data_end
= leaf_data_end(root
, leaf
);
4615 old_data_start
= btrfs_item_offset_nr(leaf
, slot
);
4617 size_diff
= old_size
- new_size
;
4620 BUG_ON(slot
>= nritems
);
4623 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4625 /* first correct the data pointers */
4626 for (i
= slot
; i
< nritems
; i
++) {
4628 item
= btrfs_item_nr(i
);
4630 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4631 btrfs_set_token_item_offset(leaf
, item
,
4632 ioff
+ size_diff
, &token
);
4635 /* shift the data */
4637 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4638 data_end
+ size_diff
, btrfs_leaf_data(leaf
) +
4639 data_end
, old_data_start
+ new_size
- data_end
);
4641 struct btrfs_disk_key disk_key
;
4644 btrfs_item_key(leaf
, &disk_key
, slot
);
4646 if (btrfs_disk_key_type(&disk_key
) == BTRFS_EXTENT_DATA_KEY
) {
4648 struct btrfs_file_extent_item
*fi
;
4650 fi
= btrfs_item_ptr(leaf
, slot
,
4651 struct btrfs_file_extent_item
);
4652 fi
= (struct btrfs_file_extent_item
*)(
4653 (unsigned long)fi
- size_diff
);
4655 if (btrfs_file_extent_type(leaf
, fi
) ==
4656 BTRFS_FILE_EXTENT_INLINE
) {
4657 ptr
= btrfs_item_ptr_offset(leaf
, slot
);
4658 memmove_extent_buffer(leaf
, ptr
,
4660 offsetof(struct btrfs_file_extent_item
,
4665 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4666 data_end
+ size_diff
, btrfs_leaf_data(leaf
) +
4667 data_end
, old_data_start
- data_end
);
4669 offset
= btrfs_disk_key_offset(&disk_key
);
4670 btrfs_set_disk_key_offset(&disk_key
, offset
+ size_diff
);
4671 btrfs_set_item_key(leaf
, &disk_key
, slot
);
4673 fixup_low_keys(root
, path
, &disk_key
, 1);
4676 item
= btrfs_item_nr(slot
);
4677 btrfs_set_item_size(leaf
, item
, new_size
);
4678 btrfs_mark_buffer_dirty(leaf
);
4680 if (btrfs_leaf_free_space(root
, leaf
) < 0) {
4681 btrfs_print_leaf(root
, leaf
);
4687 * make the item pointed to by the path bigger, data_size is the added size.
4689 void btrfs_extend_item(struct btrfs_root
*root
, struct btrfs_path
*path
,
4693 struct extent_buffer
*leaf
;
4694 struct btrfs_item
*item
;
4696 unsigned int data_end
;
4697 unsigned int old_data
;
4698 unsigned int old_size
;
4700 struct btrfs_map_token token
;
4702 btrfs_init_map_token(&token
);
4704 leaf
= path
->nodes
[0];
4706 nritems
= btrfs_header_nritems(leaf
);
4707 data_end
= leaf_data_end(root
, leaf
);
4709 if (btrfs_leaf_free_space(root
, leaf
) < data_size
) {
4710 btrfs_print_leaf(root
, leaf
);
4713 slot
= path
->slots
[0];
4714 old_data
= btrfs_item_end_nr(leaf
, slot
);
4717 if (slot
>= nritems
) {
4718 btrfs_print_leaf(root
, leaf
);
4719 btrfs_crit(root
->fs_info
, "slot %d too large, nritems %d",
4725 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4727 /* first correct the data pointers */
4728 for (i
= slot
; i
< nritems
; i
++) {
4730 item
= btrfs_item_nr(i
);
4732 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4733 btrfs_set_token_item_offset(leaf
, item
,
4734 ioff
- data_size
, &token
);
4737 /* shift the data */
4738 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4739 data_end
- data_size
, btrfs_leaf_data(leaf
) +
4740 data_end
, old_data
- data_end
);
4742 data_end
= old_data
;
4743 old_size
= btrfs_item_size_nr(leaf
, slot
);
4744 item
= btrfs_item_nr(slot
);
4745 btrfs_set_item_size(leaf
, item
, old_size
+ data_size
);
4746 btrfs_mark_buffer_dirty(leaf
);
4748 if (btrfs_leaf_free_space(root
, leaf
) < 0) {
4749 btrfs_print_leaf(root
, leaf
);
4755 * this is a helper for btrfs_insert_empty_items, the main goal here is
4756 * to save stack depth by doing the bulk of the work in a function
4757 * that doesn't call btrfs_search_slot
4759 void setup_items_for_insert(struct btrfs_root
*root
, struct btrfs_path
*path
,
4760 struct btrfs_key
*cpu_key
, u32
*data_size
,
4761 u32 total_data
, u32 total_size
, int nr
)
4763 struct btrfs_item
*item
;
4766 unsigned int data_end
;
4767 struct btrfs_disk_key disk_key
;
4768 struct extent_buffer
*leaf
;
4770 struct btrfs_map_token token
;
4772 btrfs_init_map_token(&token
);
4774 leaf
= path
->nodes
[0];
4775 slot
= path
->slots
[0];
4777 nritems
= btrfs_header_nritems(leaf
);
4778 data_end
= leaf_data_end(root
, leaf
);
4780 if (btrfs_leaf_free_space(root
, leaf
) < total_size
) {
4781 btrfs_print_leaf(root
, leaf
);
4782 btrfs_crit(root
->fs_info
, "not enough freespace need %u have %d",
4783 total_size
, btrfs_leaf_free_space(root
, leaf
));
4787 if (slot
!= nritems
) {
4788 unsigned int old_data
= btrfs_item_end_nr(leaf
, slot
);
4790 if (old_data
< data_end
) {
4791 btrfs_print_leaf(root
, leaf
);
4792 btrfs_crit(root
->fs_info
, "slot %d old_data %d data_end %d",
4793 slot
, old_data
, data_end
);
4797 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4799 /* first correct the data pointers */
4800 for (i
= slot
; i
< nritems
; i
++) {
4803 item
= btrfs_item_nr( i
);
4804 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
4805 btrfs_set_token_item_offset(leaf
, item
,
4806 ioff
- total_data
, &token
);
4808 /* shift the items */
4809 memmove_extent_buffer(leaf
, btrfs_item_nr_offset(slot
+ nr
),
4810 btrfs_item_nr_offset(slot
),
4811 (nritems
- slot
) * sizeof(struct btrfs_item
));
4813 /* shift the data */
4814 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
4815 data_end
- total_data
, btrfs_leaf_data(leaf
) +
4816 data_end
, old_data
- data_end
);
4817 data_end
= old_data
;
4820 /* setup the item for the new data */
4821 for (i
= 0; i
< nr
; i
++) {
4822 btrfs_cpu_key_to_disk(&disk_key
, cpu_key
+ i
);
4823 btrfs_set_item_key(leaf
, &disk_key
, slot
+ i
);
4824 item
= btrfs_item_nr(slot
+ i
);
4825 btrfs_set_token_item_offset(leaf
, item
,
4826 data_end
- data_size
[i
], &token
);
4827 data_end
-= data_size
[i
];
4828 btrfs_set_token_item_size(leaf
, item
, data_size
[i
], &token
);
4831 btrfs_set_header_nritems(leaf
, nritems
+ nr
);
4834 btrfs_cpu_key_to_disk(&disk_key
, cpu_key
);
4835 fixup_low_keys(root
, path
, &disk_key
, 1);
4837 btrfs_unlock_up_safe(path
, 1);
4838 btrfs_mark_buffer_dirty(leaf
);
4840 if (btrfs_leaf_free_space(root
, leaf
) < 0) {
4841 btrfs_print_leaf(root
, leaf
);
4847 * Given a key and some data, insert items into the tree.
4848 * This does all the path init required, making room in the tree if needed.
4850 int btrfs_insert_empty_items(struct btrfs_trans_handle
*trans
,
4851 struct btrfs_root
*root
,
4852 struct btrfs_path
*path
,
4853 struct btrfs_key
*cpu_key
, u32
*data_size
,
4862 for (i
= 0; i
< nr
; i
++)
4863 total_data
+= data_size
[i
];
4865 total_size
= total_data
+ (nr
* sizeof(struct btrfs_item
));
4866 ret
= btrfs_search_slot(trans
, root
, cpu_key
, path
, total_size
, 1);
4872 slot
= path
->slots
[0];
4875 setup_items_for_insert(root
, path
, cpu_key
, data_size
,
4876 total_data
, total_size
, nr
);
4881 * Given a key and some data, insert an item into the tree.
4882 * This does all the path init required, making room in the tree if needed.
4884 int btrfs_insert_item(struct btrfs_trans_handle
*trans
, struct btrfs_root
4885 *root
, struct btrfs_key
*cpu_key
, void *data
, u32
4889 struct btrfs_path
*path
;
4890 struct extent_buffer
*leaf
;
4893 path
= btrfs_alloc_path();
4896 ret
= btrfs_insert_empty_item(trans
, root
, path
, cpu_key
, data_size
);
4898 leaf
= path
->nodes
[0];
4899 ptr
= btrfs_item_ptr_offset(leaf
, path
->slots
[0]);
4900 write_extent_buffer(leaf
, data
, ptr
, data_size
);
4901 btrfs_mark_buffer_dirty(leaf
);
4903 btrfs_free_path(path
);
4908 * delete the pointer from a given node.
4910 * the tree should have been previously balanced so the deletion does not
4913 static void del_ptr(struct btrfs_root
*root
, struct btrfs_path
*path
,
4914 int level
, int slot
)
4916 struct extent_buffer
*parent
= path
->nodes
[level
];
4920 nritems
= btrfs_header_nritems(parent
);
4921 if (slot
!= nritems
- 1) {
4923 tree_mod_log_eb_move(root
->fs_info
, parent
, slot
,
4924 slot
+ 1, nritems
- slot
- 1);
4925 memmove_extent_buffer(parent
,
4926 btrfs_node_key_ptr_offset(slot
),
4927 btrfs_node_key_ptr_offset(slot
+ 1),
4928 sizeof(struct btrfs_key_ptr
) *
4929 (nritems
- slot
- 1));
4931 ret
= tree_mod_log_insert_key(root
->fs_info
, parent
, slot
,
4932 MOD_LOG_KEY_REMOVE
, GFP_NOFS
);
4937 btrfs_set_header_nritems(parent
, nritems
);
4938 if (nritems
== 0 && parent
== root
->node
) {
4939 BUG_ON(btrfs_header_level(root
->node
) != 1);
4940 /* just turn the root into a leaf and break */
4941 btrfs_set_header_level(root
->node
, 0);
4942 } else if (slot
== 0) {
4943 struct btrfs_disk_key disk_key
;
4945 btrfs_node_key(parent
, &disk_key
, 0);
4946 fixup_low_keys(root
, path
, &disk_key
, level
+ 1);
4948 btrfs_mark_buffer_dirty(parent
);
4952 * a helper function to delete the leaf pointed to by path->slots[1] and
4955 * This deletes the pointer in path->nodes[1] and frees the leaf
4956 * block extent. zero is returned if it all worked out, < 0 otherwise.
4958 * The path must have already been setup for deleting the leaf, including
4959 * all the proper balancing. path->nodes[1] must be locked.
4961 static noinline
void btrfs_del_leaf(struct btrfs_trans_handle
*trans
,
4962 struct btrfs_root
*root
,
4963 struct btrfs_path
*path
,
4964 struct extent_buffer
*leaf
)
4966 WARN_ON(btrfs_header_generation(leaf
) != trans
->transid
);
4967 del_ptr(root
, path
, 1, path
->slots
[1]);
4970 * btrfs_free_extent is expensive, we want to make sure we
4971 * aren't holding any locks when we call it
4973 btrfs_unlock_up_safe(path
, 0);
4975 root_sub_used(root
, leaf
->len
);
4977 extent_buffer_get(leaf
);
4978 btrfs_free_tree_block(trans
, root
, leaf
, 0, 1);
4979 free_extent_buffer_stale(leaf
);
4982 * delete the item at the leaf level in path. If that empties
4983 * the leaf, remove it from the tree
4985 int btrfs_del_items(struct btrfs_trans_handle
*trans
, struct btrfs_root
*root
,
4986 struct btrfs_path
*path
, int slot
, int nr
)
4988 struct extent_buffer
*leaf
;
4989 struct btrfs_item
*item
;
4996 struct btrfs_map_token token
;
4998 btrfs_init_map_token(&token
);
5000 leaf
= path
->nodes
[0];
5001 last_off
= btrfs_item_offset_nr(leaf
, slot
+ nr
- 1);
5003 for (i
= 0; i
< nr
; i
++)
5004 dsize
+= btrfs_item_size_nr(leaf
, slot
+ i
);
5006 nritems
= btrfs_header_nritems(leaf
);
5008 if (slot
+ nr
!= nritems
) {
5009 int data_end
= leaf_data_end(root
, leaf
);
5011 memmove_extent_buffer(leaf
, btrfs_leaf_data(leaf
) +
5013 btrfs_leaf_data(leaf
) + data_end
,
5014 last_off
- data_end
);
5016 for (i
= slot
+ nr
; i
< nritems
; i
++) {
5019 item
= btrfs_item_nr(i
);
5020 ioff
= btrfs_token_item_offset(leaf
, item
, &token
);
5021 btrfs_set_token_item_offset(leaf
, item
,
5022 ioff
+ dsize
, &token
);
5025 memmove_extent_buffer(leaf
, btrfs_item_nr_offset(slot
),
5026 btrfs_item_nr_offset(slot
+ nr
),
5027 sizeof(struct btrfs_item
) *
5028 (nritems
- slot
- nr
));
5030 btrfs_set_header_nritems(leaf
, nritems
- nr
);
5033 /* delete the leaf if we've emptied it */
5035 if (leaf
== root
->node
) {
5036 btrfs_set_header_level(leaf
, 0);
5038 btrfs_set_path_blocking(path
);
5039 clean_tree_block(trans
, root
, leaf
);
5040 btrfs_del_leaf(trans
, root
, path
, leaf
);
5043 int used
= leaf_space_used(leaf
, 0, nritems
);
5045 struct btrfs_disk_key disk_key
;
5047 btrfs_item_key(leaf
, &disk_key
, 0);
5048 fixup_low_keys(root
, path
, &disk_key
, 1);
5051 /* delete the leaf if it is mostly empty */
5052 if (used
< BTRFS_LEAF_DATA_SIZE(root
) / 3) {
5053 /* push_leaf_left fixes the path.
5054 * make sure the path still points to our leaf
5055 * for possible call to del_ptr below
5057 slot
= path
->slots
[1];
5058 extent_buffer_get(leaf
);
5060 btrfs_set_path_blocking(path
);
5061 wret
= push_leaf_left(trans
, root
, path
, 1, 1,
5063 if (wret
< 0 && wret
!= -ENOSPC
)
5066 if (path
->nodes
[0] == leaf
&&
5067 btrfs_header_nritems(leaf
)) {
5068 wret
= push_leaf_right(trans
, root
, path
, 1,
5070 if (wret
< 0 && wret
!= -ENOSPC
)
5074 if (btrfs_header_nritems(leaf
) == 0) {
5075 path
->slots
[1] = slot
;
5076 btrfs_del_leaf(trans
, root
, path
, leaf
);
5077 free_extent_buffer(leaf
);
5080 /* if we're still in the path, make sure
5081 * we're dirty. Otherwise, one of the
5082 * push_leaf functions must have already
5083 * dirtied this buffer
5085 if (path
->nodes
[0] == leaf
)
5086 btrfs_mark_buffer_dirty(leaf
);
5087 free_extent_buffer(leaf
);
5090 btrfs_mark_buffer_dirty(leaf
);
5097 * search the tree again to find a leaf with lesser keys
5098 * returns 0 if it found something or 1 if there are no lesser leaves.
5099 * returns < 0 on io errors.
5101 * This may release the path, and so you may lose any locks held at the
5104 int btrfs_prev_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
)
5106 struct btrfs_key key
;
5107 struct btrfs_disk_key found_key
;
5110 btrfs_item_key_to_cpu(path
->nodes
[0], &key
, 0);
5112 if (key
.offset
> 0) {
5114 } else if (key
.type
> 0) {
5116 key
.offset
= (u64
)-1;
5117 } else if (key
.objectid
> 0) {
5120 key
.offset
= (u64
)-1;
5125 btrfs_release_path(path
);
5126 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
5129 btrfs_item_key(path
->nodes
[0], &found_key
, 0);
5130 ret
= comp_keys(&found_key
, &key
);
5137 * A helper function to walk down the tree starting at min_key, and looking
5138 * for nodes or leaves that are have a minimum transaction id.
5139 * This is used by the btree defrag code, and tree logging
5141 * This does not cow, but it does stuff the starting key it finds back
5142 * into min_key, so you can call btrfs_search_slot with cow=1 on the
5143 * key and get a writable path.
5145 * This does lock as it descends, and path->keep_locks should be set
5146 * to 1 by the caller.
5148 * This honors path->lowest_level to prevent descent past a given level
5151 * min_trans indicates the oldest transaction that you are interested
5152 * in walking through. Any nodes or leaves older than min_trans are
5153 * skipped over (without reading them).
5155 * returns zero if something useful was found, < 0 on error and 1 if there
5156 * was nothing in the tree that matched the search criteria.
5158 int btrfs_search_forward(struct btrfs_root
*root
, struct btrfs_key
*min_key
,
5159 struct btrfs_path
*path
,
5162 struct extent_buffer
*cur
;
5163 struct btrfs_key found_key
;
5170 WARN_ON(!path
->keep_locks
);
5172 cur
= btrfs_read_lock_root_node(root
);
5173 level
= btrfs_header_level(cur
);
5174 WARN_ON(path
->nodes
[level
]);
5175 path
->nodes
[level
] = cur
;
5176 path
->locks
[level
] = BTRFS_READ_LOCK
;
5178 if (btrfs_header_generation(cur
) < min_trans
) {
5183 nritems
= btrfs_header_nritems(cur
);
5184 level
= btrfs_header_level(cur
);
5185 sret
= bin_search(cur
, min_key
, level
, &slot
);
5187 /* at the lowest level, we're done, setup the path and exit */
5188 if (level
== path
->lowest_level
) {
5189 if (slot
>= nritems
)
5192 path
->slots
[level
] = slot
;
5193 btrfs_item_key_to_cpu(cur
, &found_key
, slot
);
5196 if (sret
&& slot
> 0)
5199 * check this node pointer against the min_trans parameters.
5200 * If it is too old, old, skip to the next one.
5202 while (slot
< nritems
) {
5205 gen
= btrfs_node_ptr_generation(cur
, slot
);
5206 if (gen
< min_trans
) {
5214 * we didn't find a candidate key in this node, walk forward
5215 * and find another one
5217 if (slot
>= nritems
) {
5218 path
->slots
[level
] = slot
;
5219 btrfs_set_path_blocking(path
);
5220 sret
= btrfs_find_next_key(root
, path
, min_key
, level
,
5223 btrfs_release_path(path
);
5229 /* save our key for returning back */
5230 btrfs_node_key_to_cpu(cur
, &found_key
, slot
);
5231 path
->slots
[level
] = slot
;
5232 if (level
== path
->lowest_level
) {
5234 unlock_up(path
, level
, 1, 0, NULL
);
5237 btrfs_set_path_blocking(path
);
5238 cur
= read_node_slot(root
, cur
, slot
);
5239 BUG_ON(!cur
); /* -ENOMEM */
5241 btrfs_tree_read_lock(cur
);
5243 path
->locks
[level
- 1] = BTRFS_READ_LOCK
;
5244 path
->nodes
[level
- 1] = cur
;
5245 unlock_up(path
, level
, 1, 0, NULL
);
5246 btrfs_clear_path_blocking(path
, NULL
, 0);
5250 memcpy(min_key
, &found_key
, sizeof(found_key
));
5251 btrfs_set_path_blocking(path
);
5255 static void tree_move_down(struct btrfs_root
*root
,
5256 struct btrfs_path
*path
,
5257 int *level
, int root_level
)
5259 BUG_ON(*level
== 0);
5260 path
->nodes
[*level
- 1] = read_node_slot(root
, path
->nodes
[*level
],
5261 path
->slots
[*level
]);
5262 path
->slots
[*level
- 1] = 0;
5266 static int tree_move_next_or_upnext(struct btrfs_root
*root
,
5267 struct btrfs_path
*path
,
5268 int *level
, int root_level
)
5272 nritems
= btrfs_header_nritems(path
->nodes
[*level
]);
5274 path
->slots
[*level
]++;
5276 while (path
->slots
[*level
] >= nritems
) {
5277 if (*level
== root_level
)
5281 path
->slots
[*level
] = 0;
5282 free_extent_buffer(path
->nodes
[*level
]);
5283 path
->nodes
[*level
] = NULL
;
5285 path
->slots
[*level
]++;
5287 nritems
= btrfs_header_nritems(path
->nodes
[*level
]);
5294 * Returns 1 if it had to move up and next. 0 is returned if it moved only next
5297 static int tree_advance(struct btrfs_root
*root
,
5298 struct btrfs_path
*path
,
5299 int *level
, int root_level
,
5301 struct btrfs_key
*key
)
5305 if (*level
== 0 || !allow_down
) {
5306 ret
= tree_move_next_or_upnext(root
, path
, level
, root_level
);
5308 tree_move_down(root
, path
, level
, root_level
);
5313 btrfs_item_key_to_cpu(path
->nodes
[*level
], key
,
5314 path
->slots
[*level
]);
5316 btrfs_node_key_to_cpu(path
->nodes
[*level
], key
,
5317 path
->slots
[*level
]);
5322 static int tree_compare_item(struct btrfs_root
*left_root
,
5323 struct btrfs_path
*left_path
,
5324 struct btrfs_path
*right_path
,
5329 unsigned long off1
, off2
;
5331 len1
= btrfs_item_size_nr(left_path
->nodes
[0], left_path
->slots
[0]);
5332 len2
= btrfs_item_size_nr(right_path
->nodes
[0], right_path
->slots
[0]);
5336 off1
= btrfs_item_ptr_offset(left_path
->nodes
[0], left_path
->slots
[0]);
5337 off2
= btrfs_item_ptr_offset(right_path
->nodes
[0],
5338 right_path
->slots
[0]);
5340 read_extent_buffer(left_path
->nodes
[0], tmp_buf
, off1
, len1
);
5342 cmp
= memcmp_extent_buffer(right_path
->nodes
[0], tmp_buf
, off2
, len1
);
5349 #define ADVANCE_ONLY_NEXT -1
5352 * This function compares two trees and calls the provided callback for
5353 * every changed/new/deleted item it finds.
5354 * If shared tree blocks are encountered, whole subtrees are skipped, making
5355 * the compare pretty fast on snapshotted subvolumes.
5357 * This currently works on commit roots only. As commit roots are read only,
5358 * we don't do any locking. The commit roots are protected with transactions.
5359 * Transactions are ended and rejoined when a commit is tried in between.
5361 * This function checks for modifications done to the trees while comparing.
5362 * If it detects a change, it aborts immediately.
5364 int btrfs_compare_trees(struct btrfs_root
*left_root
,
5365 struct btrfs_root
*right_root
,
5366 btrfs_changed_cb_t changed_cb
, void *ctx
)
5370 struct btrfs_path
*left_path
= NULL
;
5371 struct btrfs_path
*right_path
= NULL
;
5372 struct btrfs_key left_key
;
5373 struct btrfs_key right_key
;
5374 char *tmp_buf
= NULL
;
5375 int left_root_level
;
5376 int right_root_level
;
5379 int left_end_reached
;
5380 int right_end_reached
;
5388 left_path
= btrfs_alloc_path();
5393 right_path
= btrfs_alloc_path();
5399 tmp_buf
= kmalloc(left_root
->leafsize
, GFP_NOFS
);
5405 left_path
->search_commit_root
= 1;
5406 left_path
->skip_locking
= 1;
5407 right_path
->search_commit_root
= 1;
5408 right_path
->skip_locking
= 1;
5411 * Strategy: Go to the first items of both trees. Then do
5413 * If both trees are at level 0
5414 * Compare keys of current items
5415 * If left < right treat left item as new, advance left tree
5417 * If left > right treat right item as deleted, advance right tree
5419 * If left == right do deep compare of items, treat as changed if
5420 * needed, advance both trees and repeat
5421 * If both trees are at the same level but not at level 0
5422 * Compare keys of current nodes/leafs
5423 * If left < right advance left tree and repeat
5424 * If left > right advance right tree and repeat
5425 * If left == right compare blockptrs of the next nodes/leafs
5426 * If they match advance both trees but stay at the same level
5428 * If they don't match advance both trees while allowing to go
5430 * If tree levels are different
5431 * Advance the tree that needs it and repeat
5433 * Advancing a tree means:
5434 * If we are at level 0, try to go to the next slot. If that's not
5435 * possible, go one level up and repeat. Stop when we found a level
5436 * where we could go to the next slot. We may at this point be on a
5439 * If we are not at level 0 and not on shared tree blocks, go one
5442 * If we are not at level 0 and on shared tree blocks, go one slot to
5443 * the right if possible or go up and right.
5446 down_read(&left_root
->fs_info
->commit_root_sem
);
5447 left_level
= btrfs_header_level(left_root
->commit_root
);
5448 left_root_level
= left_level
;
5449 left_path
->nodes
[left_level
] = left_root
->commit_root
;
5450 extent_buffer_get(left_path
->nodes
[left_level
]);
5452 right_level
= btrfs_header_level(right_root
->commit_root
);
5453 right_root_level
= right_level
;
5454 right_path
->nodes
[right_level
] = right_root
->commit_root
;
5455 extent_buffer_get(right_path
->nodes
[right_level
]);
5456 up_read(&left_root
->fs_info
->commit_root_sem
);
5458 if (left_level
== 0)
5459 btrfs_item_key_to_cpu(left_path
->nodes
[left_level
],
5460 &left_key
, left_path
->slots
[left_level
]);
5462 btrfs_node_key_to_cpu(left_path
->nodes
[left_level
],
5463 &left_key
, left_path
->slots
[left_level
]);
5464 if (right_level
== 0)
5465 btrfs_item_key_to_cpu(right_path
->nodes
[right_level
],
5466 &right_key
, right_path
->slots
[right_level
]);
5468 btrfs_node_key_to_cpu(right_path
->nodes
[right_level
],
5469 &right_key
, right_path
->slots
[right_level
]);
5471 left_end_reached
= right_end_reached
= 0;
5472 advance_left
= advance_right
= 0;
5475 if (advance_left
&& !left_end_reached
) {
5476 ret
= tree_advance(left_root
, left_path
, &left_level
,
5478 advance_left
!= ADVANCE_ONLY_NEXT
,
5481 left_end_reached
= ADVANCE
;
5484 if (advance_right
&& !right_end_reached
) {
5485 ret
= tree_advance(right_root
, right_path
, &right_level
,
5487 advance_right
!= ADVANCE_ONLY_NEXT
,
5490 right_end_reached
= ADVANCE
;
5494 if (left_end_reached
&& right_end_reached
) {
5497 } else if (left_end_reached
) {
5498 if (right_level
== 0) {
5499 ret
= changed_cb(left_root
, right_root
,
5500 left_path
, right_path
,
5502 BTRFS_COMPARE_TREE_DELETED
,
5507 advance_right
= ADVANCE
;
5509 } else if (right_end_reached
) {
5510 if (left_level
== 0) {
5511 ret
= changed_cb(left_root
, right_root
,
5512 left_path
, right_path
,
5514 BTRFS_COMPARE_TREE_NEW
,
5519 advance_left
= ADVANCE
;
5523 if (left_level
== 0 && right_level
== 0) {
5524 cmp
= btrfs_comp_cpu_keys(&left_key
, &right_key
);
5526 ret
= changed_cb(left_root
, right_root
,
5527 left_path
, right_path
,
5529 BTRFS_COMPARE_TREE_NEW
,
5533 advance_left
= ADVANCE
;
5534 } else if (cmp
> 0) {
5535 ret
= changed_cb(left_root
, right_root
,
5536 left_path
, right_path
,
5538 BTRFS_COMPARE_TREE_DELETED
,
5542 advance_right
= ADVANCE
;
5544 enum btrfs_compare_tree_result cmp
;
5546 WARN_ON(!extent_buffer_uptodate(left_path
->nodes
[0]));
5547 ret
= tree_compare_item(left_root
, left_path
,
5548 right_path
, tmp_buf
);
5550 cmp
= BTRFS_COMPARE_TREE_CHANGED
;
5552 cmp
= BTRFS_COMPARE_TREE_SAME
;
5553 ret
= changed_cb(left_root
, right_root
,
5554 left_path
, right_path
,
5555 &left_key
, cmp
, ctx
);
5558 advance_left
= ADVANCE
;
5559 advance_right
= ADVANCE
;
5561 } else if (left_level
== right_level
) {
5562 cmp
= btrfs_comp_cpu_keys(&left_key
, &right_key
);
5564 advance_left
= ADVANCE
;
5565 } else if (cmp
> 0) {
5566 advance_right
= ADVANCE
;
5568 left_blockptr
= btrfs_node_blockptr(
5569 left_path
->nodes
[left_level
],
5570 left_path
->slots
[left_level
]);
5571 right_blockptr
= btrfs_node_blockptr(
5572 right_path
->nodes
[right_level
],
5573 right_path
->slots
[right_level
]);
5574 left_gen
= btrfs_node_ptr_generation(
5575 left_path
->nodes
[left_level
],
5576 left_path
->slots
[left_level
]);
5577 right_gen
= btrfs_node_ptr_generation(
5578 right_path
->nodes
[right_level
],
5579 right_path
->slots
[right_level
]);
5580 if (left_blockptr
== right_blockptr
&&
5581 left_gen
== right_gen
) {
5583 * As we're on a shared block, don't
5584 * allow to go deeper.
5586 advance_left
= ADVANCE_ONLY_NEXT
;
5587 advance_right
= ADVANCE_ONLY_NEXT
;
5589 advance_left
= ADVANCE
;
5590 advance_right
= ADVANCE
;
5593 } else if (left_level
< right_level
) {
5594 advance_right
= ADVANCE
;
5596 advance_left
= ADVANCE
;
5601 btrfs_free_path(left_path
);
5602 btrfs_free_path(right_path
);
5608 * this is similar to btrfs_next_leaf, but does not try to preserve
5609 * and fixup the path. It looks for and returns the next key in the
5610 * tree based on the current path and the min_trans parameters.
5612 * 0 is returned if another key is found, < 0 if there are any errors
5613 * and 1 is returned if there are no higher keys in the tree
5615 * path->keep_locks should be set to 1 on the search made before
5616 * calling this function.
5618 int btrfs_find_next_key(struct btrfs_root
*root
, struct btrfs_path
*path
,
5619 struct btrfs_key
*key
, int level
, u64 min_trans
)
5622 struct extent_buffer
*c
;
5624 WARN_ON(!path
->keep_locks
);
5625 while (level
< BTRFS_MAX_LEVEL
) {
5626 if (!path
->nodes
[level
])
5629 slot
= path
->slots
[level
] + 1;
5630 c
= path
->nodes
[level
];
5632 if (slot
>= btrfs_header_nritems(c
)) {
5635 struct btrfs_key cur_key
;
5636 if (level
+ 1 >= BTRFS_MAX_LEVEL
||
5637 !path
->nodes
[level
+ 1])
5640 if (path
->locks
[level
+ 1]) {
5645 slot
= btrfs_header_nritems(c
) - 1;
5647 btrfs_item_key_to_cpu(c
, &cur_key
, slot
);
5649 btrfs_node_key_to_cpu(c
, &cur_key
, slot
);
5651 orig_lowest
= path
->lowest_level
;
5652 btrfs_release_path(path
);
5653 path
->lowest_level
= level
;
5654 ret
= btrfs_search_slot(NULL
, root
, &cur_key
, path
,
5656 path
->lowest_level
= orig_lowest
;
5660 c
= path
->nodes
[level
];
5661 slot
= path
->slots
[level
];
5668 btrfs_item_key_to_cpu(c
, key
, slot
);
5670 u64 gen
= btrfs_node_ptr_generation(c
, slot
);
5672 if (gen
< min_trans
) {
5676 btrfs_node_key_to_cpu(c
, key
, slot
);
5684 * search the tree again to find a leaf with greater keys
5685 * returns 0 if it found something or 1 if there are no greater leaves.
5686 * returns < 0 on io errors.
5688 int btrfs_next_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
)
5690 return btrfs_next_old_leaf(root
, path
, 0);
5693 int btrfs_next_old_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
,
5698 struct extent_buffer
*c
;
5699 struct extent_buffer
*next
;
5700 struct btrfs_key key
;
5703 int old_spinning
= path
->leave_spinning
;
5704 int next_rw_lock
= 0;
5706 nritems
= btrfs_header_nritems(path
->nodes
[0]);
5710 btrfs_item_key_to_cpu(path
->nodes
[0], &key
, nritems
- 1);
5715 btrfs_release_path(path
);
5717 path
->keep_locks
= 1;
5718 path
->leave_spinning
= 1;
5721 ret
= btrfs_search_old_slot(root
, &key
, path
, time_seq
);
5723 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
5724 path
->keep_locks
= 0;
5729 nritems
= btrfs_header_nritems(path
->nodes
[0]);
5731 * by releasing the path above we dropped all our locks. A balance
5732 * could have added more items next to the key that used to be
5733 * at the very end of the block. So, check again here and
5734 * advance the path if there are now more items available.
5736 if (nritems
> 0 && path
->slots
[0] < nritems
- 1) {
5743 while (level
< BTRFS_MAX_LEVEL
) {
5744 if (!path
->nodes
[level
]) {
5749 slot
= path
->slots
[level
] + 1;
5750 c
= path
->nodes
[level
];
5751 if (slot
>= btrfs_header_nritems(c
)) {
5753 if (level
== BTRFS_MAX_LEVEL
) {
5761 btrfs_tree_unlock_rw(next
, next_rw_lock
);
5762 free_extent_buffer(next
);
5766 next_rw_lock
= path
->locks
[level
];
5767 ret
= read_block_for_search(NULL
, root
, path
, &next
, level
,
5773 btrfs_release_path(path
);
5777 if (!path
->skip_locking
) {
5778 ret
= btrfs_try_tree_read_lock(next
);
5779 if (!ret
&& time_seq
) {
5781 * If we don't get the lock, we may be racing
5782 * with push_leaf_left, holding that lock while
5783 * itself waiting for the leaf we've currently
5784 * locked. To solve this situation, we give up
5785 * on our lock and cycle.
5787 free_extent_buffer(next
);
5788 btrfs_release_path(path
);
5793 btrfs_set_path_blocking(path
);
5794 btrfs_tree_read_lock(next
);
5795 btrfs_clear_path_blocking(path
, next
,
5798 next_rw_lock
= BTRFS_READ_LOCK
;
5802 path
->slots
[level
] = slot
;
5805 c
= path
->nodes
[level
];
5806 if (path
->locks
[level
])
5807 btrfs_tree_unlock_rw(c
, path
->locks
[level
]);
5809 free_extent_buffer(c
);
5810 path
->nodes
[level
] = next
;
5811 path
->slots
[level
] = 0;
5812 if (!path
->skip_locking
)
5813 path
->locks
[level
] = next_rw_lock
;
5817 ret
= read_block_for_search(NULL
, root
, path
, &next
, level
,
5823 btrfs_release_path(path
);
5827 if (!path
->skip_locking
) {
5828 ret
= btrfs_try_tree_read_lock(next
);
5830 btrfs_set_path_blocking(path
);
5831 btrfs_tree_read_lock(next
);
5832 btrfs_clear_path_blocking(path
, next
,
5835 next_rw_lock
= BTRFS_READ_LOCK
;
5840 unlock_up(path
, 0, 1, 0, NULL
);
5841 path
->leave_spinning
= old_spinning
;
5843 btrfs_set_path_blocking(path
);
5849 * this uses btrfs_prev_leaf to walk backwards in the tree, and keeps
5850 * searching until it gets past min_objectid or finds an item of 'type'
5852 * returns 0 if something is found, 1 if nothing was found and < 0 on error
5854 int btrfs_previous_item(struct btrfs_root
*root
,
5855 struct btrfs_path
*path
, u64 min_objectid
,
5858 struct btrfs_key found_key
;
5859 struct extent_buffer
*leaf
;
5864 if (path
->slots
[0] == 0) {
5865 btrfs_set_path_blocking(path
);
5866 ret
= btrfs_prev_leaf(root
, path
);
5872 leaf
= path
->nodes
[0];
5873 nritems
= btrfs_header_nritems(leaf
);
5876 if (path
->slots
[0] == nritems
)
5879 btrfs_item_key_to_cpu(leaf
, &found_key
, path
->slots
[0]);
5880 if (found_key
.objectid
< min_objectid
)
5882 if (found_key
.type
== type
)
5884 if (found_key
.objectid
== min_objectid
&&
5885 found_key
.type
< type
)
5892 * search in extent tree to find a previous Metadata/Data extent item with
5895 * returns 0 if something is found, 1 if nothing was found and < 0 on error
5897 int btrfs_previous_extent_item(struct btrfs_root
*root
,
5898 struct btrfs_path
*path
, u64 min_objectid
)
5900 struct btrfs_key found_key
;
5901 struct extent_buffer
*leaf
;
5906 if (path
->slots
[0] == 0) {
5907 btrfs_set_path_blocking(path
);
5908 ret
= btrfs_prev_leaf(root
, path
);
5914 leaf
= path
->nodes
[0];
5915 nritems
= btrfs_header_nritems(leaf
);
5918 if (path
->slots
[0] == nritems
)
5921 btrfs_item_key_to_cpu(leaf
, &found_key
, path
->slots
[0]);
5922 if (found_key
.objectid
< min_objectid
)
5924 if (found_key
.type
== BTRFS_EXTENT_ITEM_KEY
||
5925 found_key
.type
== BTRFS_METADATA_ITEM_KEY
)
5927 if (found_key
.objectid
== min_objectid
&&
5928 found_key
.type
< BTRFS_EXTENT_ITEM_KEY
)