1 #include <linux/module.h>
4 #include "transaction.h"
6 static int split_node(struct btrfs_trans_handle
*trans
, struct btrfs_root
7 *root
, struct btrfs_path
*path
, int level
);
8 static int split_leaf(struct btrfs_trans_handle
*trans
, struct btrfs_root
9 *root
, struct btrfs_key
*ins_key
,
10 struct btrfs_path
*path
, int data_size
);
11 static int push_node_left(struct btrfs_trans_handle
*trans
, struct btrfs_root
12 *root
, struct buffer_head
*dst
, struct buffer_head
14 static int balance_node_right(struct btrfs_trans_handle
*trans
, struct
15 btrfs_root
*root
, struct buffer_head
*dst_buf
,
16 struct buffer_head
*src_buf
);
17 static int del_ptr(struct btrfs_trans_handle
*trans
, struct btrfs_root
*root
,
18 struct btrfs_path
*path
, int level
, int slot
);
20 inline void btrfs_init_path(struct btrfs_path
*p
)
22 memset(p
, 0, sizeof(*p
));
25 struct btrfs_path
*btrfs_alloc_path(void)
27 struct btrfs_path
*path
;
28 path
= kmem_cache_alloc(btrfs_path_cachep
, GFP_NOFS
);
30 btrfs_init_path(path
);
34 void btrfs_free_path(struct btrfs_path
*p
)
36 btrfs_release_path(NULL
, p
);
37 kmem_cache_free(btrfs_path_cachep
, p
);
40 void btrfs_release_path(struct btrfs_root
*root
, struct btrfs_path
*p
)
43 for (i
= 0; i
< BTRFS_MAX_LEVEL
; i
++) {
46 btrfs_block_release(root
, p
->nodes
[i
]);
48 memset(p
, 0, sizeof(*p
));
51 static int btrfs_cow_block(struct btrfs_trans_handle
*trans
, struct btrfs_root
52 *root
, struct buffer_head
*buf
, struct buffer_head
53 *parent
, int parent_slot
, struct buffer_head
56 struct buffer_head
*cow
;
57 struct btrfs_node
*cow_node
;
59 if (btrfs_header_generation(btrfs_buffer_header(buf
)) ==
64 cow
= btrfs_alloc_free_block(trans
, root
);
65 cow_node
= btrfs_buffer_node(cow
);
66 if (buf
->b_size
!= root
->blocksize
|| cow
->b_size
!= root
->blocksize
)
68 memcpy(cow_node
, btrfs_buffer_node(buf
), root
->blocksize
);
69 btrfs_set_header_blocknr(&cow_node
->header
, bh_blocknr(cow
));
70 btrfs_set_header_generation(&cow_node
->header
, trans
->transid
);
71 btrfs_inc_ref(trans
, root
, buf
);
72 if (buf
== root
->node
) {
75 if (buf
!= root
->commit_root
) {
76 btrfs_free_extent(trans
, root
, bh_blocknr(buf
), 1, 1);
78 btrfs_block_release(root
, buf
);
80 btrfs_set_node_blockptr(btrfs_buffer_node(parent
), parent_slot
,
82 btrfs_mark_buffer_dirty(parent
);
83 btrfs_free_extent(trans
, root
, bh_blocknr(buf
), 1, 1);
85 btrfs_block_release(root
, buf
);
86 mark_buffer_dirty(cow
);
92 * The leaf data grows from end-to-front in the node.
93 * this returns the address of the start of the last item,
94 * which is the stop of the leaf data stack
96 static inline unsigned int leaf_data_end(struct btrfs_root
*root
,
97 struct btrfs_leaf
*leaf
)
99 u32 nr
= btrfs_header_nritems(&leaf
->header
);
101 return BTRFS_LEAF_DATA_SIZE(root
);
102 return btrfs_item_offset(leaf
->items
+ nr
- 1);
106 * compare two keys in a memcmp fashion
108 static int comp_keys(struct btrfs_disk_key
*disk
, struct btrfs_key
*k2
)
112 btrfs_disk_key_to_cpu(&k1
, disk
);
114 if (k1
.objectid
> k2
->objectid
)
116 if (k1
.objectid
< k2
->objectid
)
118 if (k1
.offset
> k2
->offset
)
120 if (k1
.offset
< k2
->offset
)
122 if (k1
.flags
> k2
->flags
)
124 if (k1
.flags
< k2
->flags
)
129 static int check_node(struct btrfs_root
*root
, struct btrfs_path
*path
,
133 struct btrfs_node
*parent
= NULL
;
134 struct btrfs_node
*node
= btrfs_buffer_node(path
->nodes
[level
]);
136 u32 nritems
= btrfs_header_nritems(&node
->header
);
138 if (path
->nodes
[level
+ 1])
139 parent
= btrfs_buffer_node(path
->nodes
[level
+ 1]);
140 parent_slot
= path
->slots
[level
+ 1];
141 BUG_ON(nritems
== 0);
143 struct btrfs_disk_key
*parent_key
;
144 parent_key
= &parent
->ptrs
[parent_slot
].key
;
145 BUG_ON(memcmp(parent_key
, &node
->ptrs
[0].key
,
146 sizeof(struct btrfs_disk_key
)));
147 BUG_ON(btrfs_node_blockptr(parent
, parent_slot
) !=
148 btrfs_header_blocknr(&node
->header
));
150 BUG_ON(nritems
> BTRFS_NODEPTRS_PER_BLOCK(root
));
151 for (i
= 0; nritems
> 1 && i
< nritems
- 2; i
++) {
152 struct btrfs_key cpukey
;
153 btrfs_disk_key_to_cpu(&cpukey
, &node
->ptrs
[i
+ 1].key
);
154 BUG_ON(comp_keys(&node
->ptrs
[i
].key
, &cpukey
) >= 0);
159 static int check_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
,
163 struct btrfs_leaf
*leaf
= btrfs_buffer_leaf(path
->nodes
[level
]);
164 struct btrfs_node
*parent
= NULL
;
166 u32 nritems
= btrfs_header_nritems(&leaf
->header
);
168 if (path
->nodes
[level
+ 1])
169 parent
= btrfs_buffer_node(path
->nodes
[level
+ 1]);
170 parent_slot
= path
->slots
[level
+ 1];
171 BUG_ON(btrfs_leaf_free_space(root
, leaf
) < 0);
177 struct btrfs_disk_key
*parent_key
;
178 parent_key
= &parent
->ptrs
[parent_slot
].key
;
179 BUG_ON(memcmp(parent_key
, &leaf
->items
[0].key
,
180 sizeof(struct btrfs_disk_key
)));
181 BUG_ON(btrfs_node_blockptr(parent
, parent_slot
) !=
182 btrfs_header_blocknr(&leaf
->header
));
184 for (i
= 0; nritems
> 1 && i
< nritems
- 2; i
++) {
185 struct btrfs_key cpukey
;
186 btrfs_disk_key_to_cpu(&cpukey
, &leaf
->items
[i
+ 1].key
);
187 BUG_ON(comp_keys(&leaf
->items
[i
].key
,
189 BUG_ON(btrfs_item_offset(leaf
->items
+ i
) !=
190 btrfs_item_end(leaf
->items
+ i
+ 1));
192 BUG_ON(btrfs_item_offset(leaf
->items
+ i
) +
193 btrfs_item_size(leaf
->items
+ i
) !=
194 BTRFS_LEAF_DATA_SIZE(root
));
200 static int check_block(struct btrfs_root
*root
, struct btrfs_path
*path
,
203 struct btrfs_node
*node
= btrfs_buffer_node(path
->nodes
[level
]);
204 if (memcmp(node
->header
.fsid
, root
->fs_info
->disk_super
->fsid
,
205 sizeof(node
->header
.fsid
)))
208 return check_leaf(root
, path
, level
);
209 return check_node(root
, path
, level
);
213 * search for key in the array p. items p are item_size apart
214 * and there are 'max' items in p
215 * the slot in the array is returned via slot, and it points to
216 * the place where you would insert key if it is not found in
219 * slot may point to max if the key is bigger than all of the keys
221 static int generic_bin_search(char *p
, int item_size
, struct btrfs_key
*key
,
228 struct btrfs_disk_key
*tmp
;
231 mid
= (low
+ high
) / 2;
232 tmp
= (struct btrfs_disk_key
*)(p
+ mid
* item_size
);
233 ret
= comp_keys(tmp
, key
);
249 * simple bin_search frontend that does the right thing for
252 static int bin_search(struct btrfs_node
*c
, struct btrfs_key
*key
, int *slot
)
254 if (btrfs_is_leaf(c
)) {
255 struct btrfs_leaf
*l
= (struct btrfs_leaf
*)c
;
256 return generic_bin_search((void *)l
->items
,
257 sizeof(struct btrfs_item
),
258 key
, btrfs_header_nritems(&c
->header
),
261 return generic_bin_search((void *)c
->ptrs
,
262 sizeof(struct btrfs_key_ptr
),
263 key
, btrfs_header_nritems(&c
->header
),
269 static struct buffer_head
*read_node_slot(struct btrfs_root
*root
,
270 struct buffer_head
*parent_buf
,
273 struct btrfs_node
*node
= btrfs_buffer_node(parent_buf
);
276 if (slot
>= btrfs_header_nritems(&node
->header
))
278 return read_tree_block(root
, btrfs_node_blockptr(node
, slot
));
281 static int balance_level(struct btrfs_trans_handle
*trans
, struct btrfs_root
282 *root
, struct btrfs_path
*path
, int level
)
284 struct buffer_head
*right_buf
;
285 struct buffer_head
*mid_buf
;
286 struct buffer_head
*left_buf
;
287 struct buffer_head
*parent_buf
= NULL
;
288 struct btrfs_node
*right
= NULL
;
289 struct btrfs_node
*mid
;
290 struct btrfs_node
*left
= NULL
;
291 struct btrfs_node
*parent
= NULL
;
295 int orig_slot
= path
->slots
[level
];
301 mid_buf
= path
->nodes
[level
];
302 mid
= btrfs_buffer_node(mid_buf
);
303 orig_ptr
= btrfs_node_blockptr(mid
, orig_slot
);
305 if (level
< BTRFS_MAX_LEVEL
- 1)
306 parent_buf
= path
->nodes
[level
+ 1];
307 pslot
= path
->slots
[level
+ 1];
310 * deal with the case where there is only one pointer in the root
311 * by promoting the node below to a root
314 struct buffer_head
*child
;
315 u64 blocknr
= bh_blocknr(mid_buf
);
317 if (btrfs_header_nritems(&mid
->header
) != 1)
320 /* promote the child to a root */
321 child
= read_node_slot(root
, mid_buf
, 0);
324 path
->nodes
[level
] = NULL
;
325 clean_tree_block(trans
, root
, mid_buf
);
326 wait_on_buffer(mid_buf
);
327 /* once for the path */
328 btrfs_block_release(root
, mid_buf
);
329 /* once for the root ptr */
330 btrfs_block_release(root
, mid_buf
);
331 return btrfs_free_extent(trans
, root
, blocknr
, 1, 1);
333 parent
= btrfs_buffer_node(parent_buf
);
335 if (btrfs_header_nritems(&mid
->header
) >
336 BTRFS_NODEPTRS_PER_BLOCK(root
) / 4)
339 left_buf
= read_node_slot(root
, parent_buf
, pslot
- 1);
340 right_buf
= read_node_slot(root
, parent_buf
, pslot
+ 1);
342 /* first, try to make some room in the middle buffer */
344 btrfs_cow_block(trans
, root
, left_buf
, parent_buf
, pslot
- 1,
346 left
= btrfs_buffer_node(left_buf
);
347 orig_slot
+= btrfs_header_nritems(&left
->header
);
348 wret
= push_node_left(trans
, root
, left_buf
, mid_buf
);
354 * then try to empty the right most buffer into the middle
357 btrfs_cow_block(trans
, root
, right_buf
, parent_buf
, pslot
+ 1,
359 right
= btrfs_buffer_node(right_buf
);
360 wret
= push_node_left(trans
, root
, mid_buf
, right_buf
);
363 if (btrfs_header_nritems(&right
->header
) == 0) {
364 u64 blocknr
= bh_blocknr(right_buf
);
365 clean_tree_block(trans
, root
, right_buf
);
366 wait_on_buffer(right_buf
);
367 btrfs_block_release(root
, right_buf
);
370 wret
= del_ptr(trans
, root
, path
, level
+ 1, pslot
+
374 wret
= btrfs_free_extent(trans
, root
, blocknr
, 1, 1);
378 btrfs_memcpy(root
, parent
,
379 &parent
->ptrs
[pslot
+ 1].key
,
381 sizeof(struct btrfs_disk_key
));
382 btrfs_mark_buffer_dirty(parent_buf
);
385 if (btrfs_header_nritems(&mid
->header
) == 1) {
387 * we're not allowed to leave a node with one item in the
388 * tree during a delete. A deletion from lower in the tree
389 * could try to delete the only pointer in this node.
390 * So, pull some keys from the left.
391 * There has to be a left pointer at this point because
392 * otherwise we would have pulled some pointers from the
396 wret
= balance_node_right(trans
, root
, mid_buf
, left_buf
);
401 if (btrfs_header_nritems(&mid
->header
) == 0) {
402 /* we've managed to empty the middle node, drop it */
403 u64 blocknr
= bh_blocknr(mid_buf
);
404 clean_tree_block(trans
, root
, mid_buf
);
405 wait_on_buffer(mid_buf
);
406 btrfs_block_release(root
, mid_buf
);
409 wret
= del_ptr(trans
, root
, path
, level
+ 1, pslot
);
412 wret
= btrfs_free_extent(trans
, root
, blocknr
, 1, 1);
416 /* update the parent key to reflect our changes */
417 btrfs_memcpy(root
, parent
,
418 &parent
->ptrs
[pslot
].key
, &mid
->ptrs
[0].key
,
419 sizeof(struct btrfs_disk_key
));
420 btrfs_mark_buffer_dirty(parent_buf
);
423 /* update the path */
425 if (btrfs_header_nritems(&left
->header
) > orig_slot
) {
427 path
->nodes
[level
] = left_buf
;
428 path
->slots
[level
+ 1] -= 1;
429 path
->slots
[level
] = orig_slot
;
431 btrfs_block_release(root
, mid_buf
);
433 orig_slot
-= btrfs_header_nritems(&left
->header
);
434 path
->slots
[level
] = orig_slot
;
437 /* double check we haven't messed things up */
438 check_block(root
, path
, level
);
440 btrfs_node_blockptr(btrfs_buffer_node(path
->nodes
[level
]),
445 btrfs_block_release(root
, right_buf
);
447 btrfs_block_release(root
, left_buf
);
452 * look for key in the tree. path is filled in with nodes along the way
453 * if key is found, we return zero and you can find the item in the leaf
454 * level of the path (level 0)
456 * If the key isn't found, the path points to the slot where it should
457 * be inserted, and 1 is returned. If there are other errors during the
458 * search a negative error number is returned.
460 * if ins_len > 0, nodes and leaves will be split as we walk down the
461 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
464 int btrfs_search_slot(struct btrfs_trans_handle
*trans
, struct btrfs_root
465 *root
, struct btrfs_key
*key
, struct btrfs_path
*p
, int
468 struct buffer_head
*b
;
469 struct buffer_head
*cow_buf
;
470 struct btrfs_node
*c
;
475 WARN_ON(p
->nodes
[0] != NULL
);
476 WARN_ON(!mutex_is_locked(&root
->fs_info
->fs_mutex
));
481 c
= btrfs_buffer_node(b
);
482 level
= btrfs_header_level(&c
->header
);
485 wret
= btrfs_cow_block(trans
, root
, b
,
490 c
= btrfs_buffer_node(b
);
492 BUG_ON(!cow
&& ins_len
);
493 if (level
!= btrfs_header_level(&c
->header
))
495 level
= btrfs_header_level(&c
->header
);
497 ret
= check_block(root
, p
, level
);
500 ret
= bin_search(c
, key
, &slot
);
501 if (!btrfs_is_leaf(c
)) {
504 p
->slots
[level
] = slot
;
505 if (ins_len
> 0 && btrfs_header_nritems(&c
->header
) >=
506 BTRFS_NODEPTRS_PER_BLOCK(root
) - 1) {
507 int sret
= split_node(trans
, root
, p
, level
);
512 c
= btrfs_buffer_node(b
);
513 slot
= p
->slots
[level
];
514 } else if (ins_len
< 0) {
515 int sret
= balance_level(trans
, root
, p
,
522 c
= btrfs_buffer_node(b
);
523 slot
= p
->slots
[level
];
524 BUG_ON(btrfs_header_nritems(&c
->header
) == 1);
526 b
= read_tree_block(root
, btrfs_node_blockptr(c
, slot
));
528 struct btrfs_leaf
*l
= (struct btrfs_leaf
*)c
;
529 p
->slots
[level
] = slot
;
530 if (ins_len
> 0 && btrfs_leaf_free_space(root
, l
) <
531 sizeof(struct btrfs_item
) + ins_len
) {
532 int sret
= split_leaf(trans
, root
, key
,
545 * adjust the pointers going up the tree, starting at level
546 * making sure the right key of each node is points to 'key'.
547 * This is used after shifting pointers to the left, so it stops
548 * fixing up pointers when a given leaf/node is not in slot 0 of the
551 * If this fails to write a tree block, it returns -1, but continues
552 * fixing up the blocks in ram so the tree is consistent.
554 static int fixup_low_keys(struct btrfs_trans_handle
*trans
, struct btrfs_root
555 *root
, struct btrfs_path
*path
, struct btrfs_disk_key
560 for (i
= level
; i
< BTRFS_MAX_LEVEL
; i
++) {
561 struct btrfs_node
*t
;
562 int tslot
= path
->slots
[i
];
565 t
= btrfs_buffer_node(path
->nodes
[i
]);
566 btrfs_memcpy(root
, t
, &t
->ptrs
[tslot
].key
, key
, sizeof(*key
));
567 btrfs_mark_buffer_dirty(path
->nodes
[i
]);
575 * try to push data from one node into the next node left in the
578 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
579 * error, and > 0 if there was no room in the left hand block.
581 static int push_node_left(struct btrfs_trans_handle
*trans
, struct btrfs_root
582 *root
, struct buffer_head
*dst_buf
, struct
583 buffer_head
*src_buf
)
585 struct btrfs_node
*src
= btrfs_buffer_node(src_buf
);
586 struct btrfs_node
*dst
= btrfs_buffer_node(dst_buf
);
592 src_nritems
= btrfs_header_nritems(&src
->header
);
593 dst_nritems
= btrfs_header_nritems(&dst
->header
);
594 push_items
= BTRFS_NODEPTRS_PER_BLOCK(root
) - dst_nritems
;
595 if (push_items
<= 0) {
599 if (src_nritems
< push_items
)
600 push_items
= src_nritems
;
602 btrfs_memcpy(root
, dst
, dst
->ptrs
+ dst_nritems
, src
->ptrs
,
603 push_items
* sizeof(struct btrfs_key_ptr
));
604 if (push_items
< src_nritems
) {
605 btrfs_memmove(root
, src
, src
->ptrs
, src
->ptrs
+ push_items
,
606 (src_nritems
- push_items
) *
607 sizeof(struct btrfs_key_ptr
));
609 btrfs_set_header_nritems(&src
->header
, src_nritems
- push_items
);
610 btrfs_set_header_nritems(&dst
->header
, dst_nritems
+ push_items
);
611 btrfs_mark_buffer_dirty(src_buf
);
612 btrfs_mark_buffer_dirty(dst_buf
);
617 * try to push data from one node into the next node right in the
620 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
621 * error, and > 0 if there was no room in the right hand block.
623 * this will only push up to 1/2 the contents of the left node over
625 static int balance_node_right(struct btrfs_trans_handle
*trans
, struct
626 btrfs_root
*root
, struct buffer_head
*dst_buf
,
627 struct buffer_head
*src_buf
)
629 struct btrfs_node
*src
= btrfs_buffer_node(src_buf
);
630 struct btrfs_node
*dst
= btrfs_buffer_node(dst_buf
);
637 src_nritems
= btrfs_header_nritems(&src
->header
);
638 dst_nritems
= btrfs_header_nritems(&dst
->header
);
639 push_items
= BTRFS_NODEPTRS_PER_BLOCK(root
) - dst_nritems
;
640 if (push_items
<= 0) {
644 max_push
= src_nritems
/ 2 + 1;
645 /* don't try to empty the node */
646 if (max_push
> src_nritems
)
648 if (max_push
< push_items
)
649 push_items
= max_push
;
651 btrfs_memmove(root
, dst
, dst
->ptrs
+ push_items
, dst
->ptrs
,
652 dst_nritems
* sizeof(struct btrfs_key_ptr
));
654 btrfs_memcpy(root
, dst
, dst
->ptrs
,
655 src
->ptrs
+ src_nritems
- push_items
,
656 push_items
* sizeof(struct btrfs_key_ptr
));
658 btrfs_set_header_nritems(&src
->header
, src_nritems
- push_items
);
659 btrfs_set_header_nritems(&dst
->header
, dst_nritems
+ push_items
);
661 btrfs_mark_buffer_dirty(src_buf
);
662 btrfs_mark_buffer_dirty(dst_buf
);
667 * helper function to insert a new root level in the tree.
668 * A new node is allocated, and a single item is inserted to
669 * point to the existing root
671 * returns zero on success or < 0 on failure.
673 static int insert_new_root(struct btrfs_trans_handle
*trans
, struct btrfs_root
674 *root
, struct btrfs_path
*path
, int level
)
676 struct buffer_head
*t
;
677 struct btrfs_node
*lower
;
678 struct btrfs_node
*c
;
679 struct btrfs_disk_key
*lower_key
;
681 BUG_ON(path
->nodes
[level
]);
682 BUG_ON(path
->nodes
[level
-1] != root
->node
);
684 t
= btrfs_alloc_free_block(trans
, root
);
685 c
= btrfs_buffer_node(t
);
686 memset(c
, 0, root
->blocksize
);
687 btrfs_set_header_nritems(&c
->header
, 1);
688 btrfs_set_header_level(&c
->header
, level
);
689 btrfs_set_header_blocknr(&c
->header
, bh_blocknr(t
));
690 btrfs_set_header_generation(&c
->header
, trans
->transid
);
691 lower
= btrfs_buffer_node(path
->nodes
[level
-1]);
692 memcpy(c
->header
.fsid
, root
->fs_info
->disk_super
->fsid
,
693 sizeof(c
->header
.fsid
));
694 if (btrfs_is_leaf(lower
))
695 lower_key
= &((struct btrfs_leaf
*)lower
)->items
[0].key
;
697 lower_key
= &lower
->ptrs
[0].key
;
698 btrfs_memcpy(root
, c
, &c
->ptrs
[0].key
, lower_key
,
699 sizeof(struct btrfs_disk_key
));
700 btrfs_set_node_blockptr(c
, 0, bh_blocknr(path
->nodes
[level
- 1]));
702 btrfs_mark_buffer_dirty(t
);
704 /* the super has an extra ref to root->node */
705 btrfs_block_release(root
, root
->node
);
708 path
->nodes
[level
] = t
;
709 path
->slots
[level
] = 0;
714 * worker function to insert a single pointer in a node.
715 * the node should have enough room for the pointer already
717 * slot and level indicate where you want the key to go, and
718 * blocknr is the block the key points to.
720 * returns zero on success and < 0 on any error
722 static int insert_ptr(struct btrfs_trans_handle
*trans
, struct btrfs_root
723 *root
, struct btrfs_path
*path
, struct btrfs_disk_key
724 *key
, u64 blocknr
, int slot
, int level
)
726 struct btrfs_node
*lower
;
729 BUG_ON(!path
->nodes
[level
]);
730 lower
= btrfs_buffer_node(path
->nodes
[level
]);
731 nritems
= btrfs_header_nritems(&lower
->header
);
734 if (nritems
== BTRFS_NODEPTRS_PER_BLOCK(root
))
736 if (slot
!= nritems
) {
737 btrfs_memmove(root
, lower
, lower
->ptrs
+ slot
+ 1,
739 (nritems
- slot
) * sizeof(struct btrfs_key_ptr
));
741 btrfs_memcpy(root
, lower
, &lower
->ptrs
[slot
].key
,
742 key
, sizeof(struct btrfs_disk_key
));
743 btrfs_set_node_blockptr(lower
, slot
, blocknr
);
744 btrfs_set_header_nritems(&lower
->header
, nritems
+ 1);
745 btrfs_mark_buffer_dirty(path
->nodes
[level
]);
750 * split the node at the specified level in path in two.
751 * The path is corrected to point to the appropriate node after the split
753 * Before splitting this tries to make some room in the node by pushing
754 * left and right, if either one works, it returns right away.
756 * returns 0 on success and < 0 on failure
758 static int split_node(struct btrfs_trans_handle
*trans
, struct btrfs_root
759 *root
, struct btrfs_path
*path
, int level
)
761 struct buffer_head
*t
;
762 struct btrfs_node
*c
;
763 struct buffer_head
*split_buffer
;
764 struct btrfs_node
*split
;
770 t
= path
->nodes
[level
];
771 c
= btrfs_buffer_node(t
);
772 if (t
== root
->node
) {
773 /* trying to split the root, lets make a new one */
774 ret
= insert_new_root(trans
, root
, path
, level
+ 1);
778 c_nritems
= btrfs_header_nritems(&c
->header
);
779 split_buffer
= btrfs_alloc_free_block(trans
, root
);
780 split
= btrfs_buffer_node(split_buffer
);
781 btrfs_set_header_flags(&split
->header
, btrfs_header_flags(&c
->header
));
782 btrfs_set_header_level(&split
->header
, btrfs_header_level(&c
->header
));
783 btrfs_set_header_blocknr(&split
->header
, bh_blocknr(split_buffer
));
784 btrfs_set_header_generation(&split
->header
, trans
->transid
);
785 memcpy(split
->header
.fsid
, root
->fs_info
->disk_super
->fsid
,
786 sizeof(split
->header
.fsid
));
787 mid
= (c_nritems
+ 1) / 2;
788 btrfs_memcpy(root
, split
, split
->ptrs
, c
->ptrs
+ mid
,
789 (c_nritems
- mid
) * sizeof(struct btrfs_key_ptr
));
790 btrfs_set_header_nritems(&split
->header
, c_nritems
- mid
);
791 btrfs_set_header_nritems(&c
->header
, mid
);
794 btrfs_mark_buffer_dirty(t
);
795 btrfs_mark_buffer_dirty(split_buffer
);
796 wret
= insert_ptr(trans
, root
, path
, &split
->ptrs
[0].key
,
797 bh_blocknr(split_buffer
), path
->slots
[level
+ 1] + 1,
802 if (path
->slots
[level
] >= mid
) {
803 path
->slots
[level
] -= mid
;
804 btrfs_block_release(root
, t
);
805 path
->nodes
[level
] = split_buffer
;
806 path
->slots
[level
+ 1] += 1;
808 btrfs_block_release(root
, split_buffer
);
814 * how many bytes are required to store the items in a leaf. start
815 * and nr indicate which items in the leaf to check. This totals up the
816 * space used both by the item structs and the item data
818 static int leaf_space_used(struct btrfs_leaf
*l
, int start
, int nr
)
821 int nritems
= btrfs_header_nritems(&l
->header
);
822 int end
= min(nritems
, start
+ nr
) - 1;
826 data_len
= btrfs_item_end(l
->items
+ start
);
827 data_len
= data_len
- btrfs_item_offset(l
->items
+ end
);
828 data_len
+= sizeof(struct btrfs_item
) * nr
;
829 WARN_ON(data_len
< 0);
834 * The space between the end of the leaf items and
835 * the start of the leaf data. IOW, how much room
836 * the leaf has left for both items and data
838 int btrfs_leaf_free_space(struct btrfs_root
*root
, struct btrfs_leaf
*leaf
)
840 int nritems
= btrfs_header_nritems(&leaf
->header
);
841 return BTRFS_LEAF_DATA_SIZE(root
) - leaf_space_used(leaf
, 0, nritems
);
845 * push some data in the path leaf to the right, trying to free up at
846 * least data_size bytes. returns zero if the push worked, nonzero otherwise
848 * returns 1 if the push failed because the other node didn't have enough
849 * room, 0 if everything worked out and < 0 if there were major errors.
851 static int push_leaf_right(struct btrfs_trans_handle
*trans
, struct btrfs_root
852 *root
, struct btrfs_path
*path
, int data_size
)
854 struct buffer_head
*left_buf
= path
->nodes
[0];
855 struct btrfs_leaf
*left
= btrfs_buffer_leaf(left_buf
);
856 struct btrfs_leaf
*right
;
857 struct buffer_head
*right_buf
;
858 struct buffer_head
*upper
;
859 struct btrfs_node
*upper_node
;
865 struct btrfs_item
*item
;
869 slot
= path
->slots
[1];
870 if (!path
->nodes
[1]) {
873 upper
= path
->nodes
[1];
874 upper_node
= btrfs_buffer_node(upper
);
875 if (slot
>= btrfs_header_nritems(&upper_node
->header
) - 1) {
878 right_buf
= read_tree_block(root
,
879 btrfs_node_blockptr(btrfs_buffer_node(upper
), slot
+ 1));
880 right
= btrfs_buffer_leaf(right_buf
);
881 free_space
= btrfs_leaf_free_space(root
, right
);
882 if (free_space
< data_size
+ sizeof(struct btrfs_item
)) {
883 btrfs_block_release(root
, right_buf
);
886 /* cow and double check */
887 btrfs_cow_block(trans
, root
, right_buf
, upper
, slot
+ 1, &right_buf
);
888 right
= btrfs_buffer_leaf(right_buf
);
889 free_space
= btrfs_leaf_free_space(root
, right
);
890 if (free_space
< data_size
+ sizeof(struct btrfs_item
)) {
891 btrfs_block_release(root
, right_buf
);
895 left_nritems
= btrfs_header_nritems(&left
->header
);
896 for (i
= left_nritems
- 1; i
>= 0; i
--) {
897 item
= left
->items
+ i
;
898 if (path
->slots
[0] == i
)
899 push_space
+= data_size
+ sizeof(*item
);
900 if (btrfs_item_size(item
) + sizeof(*item
) + push_space
>
904 push_space
+= btrfs_item_size(item
) + sizeof(*item
);
906 if (push_items
== 0) {
907 btrfs_block_release(root
, right_buf
);
910 right_nritems
= btrfs_header_nritems(&right
->header
);
911 /* push left to right */
912 push_space
= btrfs_item_end(left
->items
+ left_nritems
- push_items
);
913 push_space
-= leaf_data_end(root
, left
);
914 /* make room in the right data area */
915 btrfs_memmove(root
, right
, btrfs_leaf_data(right
) +
916 leaf_data_end(root
, right
) - push_space
,
917 btrfs_leaf_data(right
) +
918 leaf_data_end(root
, right
), BTRFS_LEAF_DATA_SIZE(root
) -
919 leaf_data_end(root
, right
));
920 /* copy from the left data area */
921 btrfs_memcpy(root
, right
, btrfs_leaf_data(right
) +
922 BTRFS_LEAF_DATA_SIZE(root
) - push_space
,
923 btrfs_leaf_data(left
) + leaf_data_end(root
, left
),
925 btrfs_memmove(root
, right
, right
->items
+ push_items
, right
->items
,
926 right_nritems
* sizeof(struct btrfs_item
));
927 /* copy the items from left to right */
928 btrfs_memcpy(root
, right
, right
->items
, left
->items
+
929 left_nritems
- push_items
,
930 push_items
* sizeof(struct btrfs_item
));
932 /* update the item pointers */
933 right_nritems
+= push_items
;
934 btrfs_set_header_nritems(&right
->header
, right_nritems
);
935 push_space
= BTRFS_LEAF_DATA_SIZE(root
);
936 for (i
= 0; i
< right_nritems
; i
++) {
937 btrfs_set_item_offset(right
->items
+ i
, push_space
-
938 btrfs_item_size(right
->items
+ i
));
939 push_space
= btrfs_item_offset(right
->items
+ i
);
941 left_nritems
-= push_items
;
942 btrfs_set_header_nritems(&left
->header
, left_nritems
);
944 btrfs_mark_buffer_dirty(left_buf
);
945 btrfs_mark_buffer_dirty(right_buf
);
946 btrfs_memcpy(root
, upper_node
, &upper_node
->ptrs
[slot
+ 1].key
,
947 &right
->items
[0].key
, sizeof(struct btrfs_disk_key
));
948 btrfs_mark_buffer_dirty(upper
);
950 /* then fixup the leaf pointer in the path */
951 if (path
->slots
[0] >= left_nritems
) {
952 path
->slots
[0] -= left_nritems
;
953 btrfs_block_release(root
, path
->nodes
[0]);
954 path
->nodes
[0] = right_buf
;
957 btrfs_block_release(root
, right_buf
);
962 * push some data in the path leaf to the left, trying to free up at
963 * least data_size bytes. returns zero if the push worked, nonzero otherwise
965 static int push_leaf_left(struct btrfs_trans_handle
*trans
, struct btrfs_root
966 *root
, struct btrfs_path
*path
, int data_size
)
968 struct buffer_head
*right_buf
= path
->nodes
[0];
969 struct btrfs_leaf
*right
= btrfs_buffer_leaf(right_buf
);
970 struct buffer_head
*t
;
971 struct btrfs_leaf
*left
;
977 struct btrfs_item
*item
;
978 u32 old_left_nritems
;
982 slot
= path
->slots
[1];
986 if (!path
->nodes
[1]) {
989 t
= read_tree_block(root
,
990 btrfs_node_blockptr(btrfs_buffer_node(path
->nodes
[1]), slot
- 1));
991 left
= btrfs_buffer_leaf(t
);
992 free_space
= btrfs_leaf_free_space(root
, left
);
993 if (free_space
< data_size
+ sizeof(struct btrfs_item
)) {
994 btrfs_block_release(root
, t
);
998 /* cow and double check */
999 btrfs_cow_block(trans
, root
, t
, path
->nodes
[1], slot
- 1, &t
);
1000 left
= btrfs_buffer_leaf(t
);
1001 free_space
= btrfs_leaf_free_space(root
, left
);
1002 if (free_space
< data_size
+ sizeof(struct btrfs_item
)) {
1003 btrfs_block_release(root
, t
);
1007 for (i
= 0; i
< btrfs_header_nritems(&right
->header
); i
++) {
1008 item
= right
->items
+ i
;
1009 if (path
->slots
[0] == i
)
1010 push_space
+= data_size
+ sizeof(*item
);
1011 if (btrfs_item_size(item
) + sizeof(*item
) + push_space
>
1015 push_space
+= btrfs_item_size(item
) + sizeof(*item
);
1017 if (push_items
== 0) {
1018 btrfs_block_release(root
, t
);
1021 /* push data from right to left */
1022 btrfs_memcpy(root
, left
, left
->items
+
1023 btrfs_header_nritems(&left
->header
),
1024 right
->items
, push_items
* sizeof(struct btrfs_item
));
1025 push_space
= BTRFS_LEAF_DATA_SIZE(root
) -
1026 btrfs_item_offset(right
->items
+ push_items
-1);
1027 btrfs_memcpy(root
, left
, btrfs_leaf_data(left
) +
1028 leaf_data_end(root
, left
) - push_space
,
1029 btrfs_leaf_data(right
) +
1030 btrfs_item_offset(right
->items
+ push_items
- 1),
1032 old_left_nritems
= btrfs_header_nritems(&left
->header
);
1033 BUG_ON(old_left_nritems
< 0);
1035 for (i
= old_left_nritems
; i
< old_left_nritems
+ push_items
; i
++) {
1036 u32 ioff
= btrfs_item_offset(left
->items
+ i
);
1037 btrfs_set_item_offset(left
->items
+ i
, ioff
-
1038 (BTRFS_LEAF_DATA_SIZE(root
) -
1039 btrfs_item_offset(left
->items
+
1040 old_left_nritems
- 1)));
1042 btrfs_set_header_nritems(&left
->header
, old_left_nritems
+ push_items
);
1044 /* fixup right node */
1045 push_space
= btrfs_item_offset(right
->items
+ push_items
- 1) -
1046 leaf_data_end(root
, right
);
1047 btrfs_memmove(root
, right
, btrfs_leaf_data(right
) +
1048 BTRFS_LEAF_DATA_SIZE(root
) - push_space
,
1049 btrfs_leaf_data(right
) +
1050 leaf_data_end(root
, right
), push_space
);
1051 btrfs_memmove(root
, right
, right
->items
, right
->items
+ push_items
,
1052 (btrfs_header_nritems(&right
->header
) - push_items
) *
1053 sizeof(struct btrfs_item
));
1054 btrfs_set_header_nritems(&right
->header
,
1055 btrfs_header_nritems(&right
->header
) -
1057 push_space
= BTRFS_LEAF_DATA_SIZE(root
);
1059 for (i
= 0; i
< btrfs_header_nritems(&right
->header
); i
++) {
1060 btrfs_set_item_offset(right
->items
+ i
, push_space
-
1061 btrfs_item_size(right
->items
+ i
));
1062 push_space
= btrfs_item_offset(right
->items
+ i
);
1065 btrfs_mark_buffer_dirty(t
);
1066 btrfs_mark_buffer_dirty(right_buf
);
1068 wret
= fixup_low_keys(trans
, root
, path
, &right
->items
[0].key
, 1);
1072 /* then fixup the leaf pointer in the path */
1073 if (path
->slots
[0] < push_items
) {
1074 path
->slots
[0] += old_left_nritems
;
1075 btrfs_block_release(root
, path
->nodes
[0]);
1077 path
->slots
[1] -= 1;
1079 btrfs_block_release(root
, t
);
1080 path
->slots
[0] -= push_items
;
1082 BUG_ON(path
->slots
[0] < 0);
1087 * split the path's leaf in two, making sure there is at least data_size
1088 * available for the resulting leaf level of the path.
1090 * returns 0 if all went well and < 0 on failure.
1092 static int split_leaf(struct btrfs_trans_handle
*trans
, struct btrfs_root
1093 *root
, struct btrfs_key
*ins_key
,
1094 struct btrfs_path
*path
, int data_size
)
1096 struct buffer_head
*l_buf
;
1097 struct btrfs_leaf
*l
;
1101 struct btrfs_leaf
*right
;
1102 struct buffer_head
*right_buffer
;
1103 int space_needed
= data_size
+ sizeof(struct btrfs_item
);
1109 int double_split
= 0;
1110 struct btrfs_disk_key disk_key
;
1112 /* first try to make some room by pushing left and right */
1113 wret
= push_leaf_left(trans
, root
, path
, data_size
);
1117 wret
= push_leaf_right(trans
, root
, path
, data_size
);
1121 l_buf
= path
->nodes
[0];
1122 l
= btrfs_buffer_leaf(l_buf
);
1124 /* did the pushes work? */
1125 if (btrfs_leaf_free_space(root
, l
) >=
1126 sizeof(struct btrfs_item
) + data_size
)
1129 if (!path
->nodes
[1]) {
1130 ret
= insert_new_root(trans
, root
, path
, 1);
1134 slot
= path
->slots
[0];
1135 nritems
= btrfs_header_nritems(&l
->header
);
1136 mid
= (nritems
+ 1)/ 2;
1137 right_buffer
= btrfs_alloc_free_block(trans
, root
);
1138 BUG_ON(!right_buffer
);
1139 right
= btrfs_buffer_leaf(right_buffer
);
1140 memset(&right
->header
, 0, sizeof(right
->header
));
1141 btrfs_set_header_blocknr(&right
->header
, bh_blocknr(right_buffer
));
1142 btrfs_set_header_generation(&right
->header
, trans
->transid
);
1143 btrfs_set_header_level(&right
->header
, 0);
1144 memcpy(right
->header
.fsid
, root
->fs_info
->disk_super
->fsid
,
1145 sizeof(right
->header
.fsid
));
1148 leaf_space_used(l
, mid
, nritems
- mid
) + space_needed
>
1149 BTRFS_LEAF_DATA_SIZE(root
)) {
1150 if (slot
>= nritems
) {
1151 btrfs_cpu_key_to_disk(&disk_key
, ins_key
);
1152 btrfs_set_header_nritems(&right
->header
, 0);
1153 wret
= insert_ptr(trans
, root
, path
,
1155 bh_blocknr(right_buffer
),
1156 path
->slots
[1] + 1, 1);
1159 btrfs_block_release(root
, path
->nodes
[0]);
1160 path
->nodes
[0] = right_buffer
;
1162 path
->slots
[1] += 1;
1169 if (leaf_space_used(l
, 0, mid
+ 1) + space_needed
>
1170 BTRFS_LEAF_DATA_SIZE(root
)) {
1172 btrfs_cpu_key_to_disk(&disk_key
, ins_key
);
1173 btrfs_set_header_nritems(&right
->header
, 0);
1174 wret
= insert_ptr(trans
, root
, path
,
1176 bh_blocknr(right_buffer
),
1177 path
->slots
[1] - 1, 1);
1180 btrfs_block_release(root
, path
->nodes
[0]);
1181 path
->nodes
[0] = right_buffer
;
1183 path
->slots
[1] -= 1;
1190 btrfs_set_header_nritems(&right
->header
, nritems
- mid
);
1191 data_copy_size
= btrfs_item_end(l
->items
+ mid
) -
1192 leaf_data_end(root
, l
);
1193 btrfs_memcpy(root
, right
, right
->items
, l
->items
+ mid
,
1194 (nritems
- mid
) * sizeof(struct btrfs_item
));
1195 btrfs_memcpy(root
, right
,
1196 btrfs_leaf_data(right
) + BTRFS_LEAF_DATA_SIZE(root
) -
1197 data_copy_size
, btrfs_leaf_data(l
) +
1198 leaf_data_end(root
, l
), data_copy_size
);
1199 rt_data_off
= BTRFS_LEAF_DATA_SIZE(root
) -
1200 btrfs_item_end(l
->items
+ mid
);
1202 for (i
= 0; i
< btrfs_header_nritems(&right
->header
); i
++) {
1203 u32 ioff
= btrfs_item_offset(right
->items
+ i
);
1204 btrfs_set_item_offset(right
->items
+ i
, ioff
+ rt_data_off
);
1207 btrfs_set_header_nritems(&l
->header
, mid
);
1209 wret
= insert_ptr(trans
, root
, path
, &right
->items
[0].key
,
1210 bh_blocknr(right_buffer
), path
->slots
[1] + 1, 1);
1213 btrfs_mark_buffer_dirty(right_buffer
);
1214 btrfs_mark_buffer_dirty(l_buf
);
1215 BUG_ON(path
->slots
[0] != slot
);
1217 btrfs_block_release(root
, path
->nodes
[0]);
1218 path
->nodes
[0] = right_buffer
;
1219 path
->slots
[0] -= mid
;
1220 path
->slots
[1] += 1;
1222 btrfs_block_release(root
, right_buffer
);
1223 BUG_ON(path
->slots
[0] < 0);
1227 right_buffer
= btrfs_alloc_free_block(trans
, root
);
1228 BUG_ON(!right_buffer
);
1229 right
= btrfs_buffer_leaf(right_buffer
);
1230 memset(&right
->header
, 0, sizeof(right
->header
));
1231 btrfs_set_header_blocknr(&right
->header
, bh_blocknr(right_buffer
));
1232 btrfs_set_header_generation(&right
->header
, trans
->transid
);
1233 btrfs_set_header_level(&right
->header
, 0);
1234 memcpy(right
->header
.fsid
, root
->fs_info
->disk_super
->fsid
,
1235 sizeof(right
->header
.fsid
));
1236 btrfs_cpu_key_to_disk(&disk_key
, ins_key
);
1237 btrfs_set_header_nritems(&right
->header
, 0);
1238 wret
= insert_ptr(trans
, root
, path
,
1240 bh_blocknr(right_buffer
),
1244 btrfs_block_release(root
, path
->nodes
[0]);
1245 path
->nodes
[0] = right_buffer
;
1247 check_node(root
, path
, 1);
1248 check_leaf(root
, path
, 0);
1252 int btrfs_truncate_item(struct btrfs_trans_handle
*trans
,
1253 struct btrfs_root
*root
,
1254 struct btrfs_path
*path
,
1260 struct btrfs_leaf
*leaf
;
1261 struct buffer_head
*leaf_buf
;
1263 unsigned int data_end
;
1264 unsigned int old_data_start
;
1265 unsigned int old_size
;
1266 unsigned int size_diff
;
1269 slot_orig
= path
->slots
[0];
1270 leaf_buf
= path
->nodes
[0];
1271 leaf
= btrfs_buffer_leaf(leaf_buf
);
1273 nritems
= btrfs_header_nritems(&leaf
->header
);
1274 data_end
= leaf_data_end(root
, leaf
);
1276 slot
= path
->slots
[0];
1277 old_data_start
= btrfs_item_offset(leaf
->items
+ slot
);
1278 old_size
= btrfs_item_size(leaf
->items
+ slot
);
1279 BUG_ON(old_size
<= new_size
);
1280 size_diff
= old_size
- new_size
;
1283 BUG_ON(slot
>= nritems
);
1286 * item0..itemN ... dataN.offset..dataN.size .. data0.size
1288 /* first correct the data pointers */
1289 for (i
= slot
; i
< nritems
; i
++) {
1290 u32 ioff
= btrfs_item_offset(leaf
->items
+ i
);
1291 btrfs_set_item_offset(leaf
->items
+ i
,
1294 /* shift the data */
1295 printk("truncate item, new_size %u old_size %u, diff %u, bufp %p, dst, %p, num %u, old_data_start %u, data_end %u\n", new_size
, old_size
, size_diff
, leaf
, btrfs_leaf_data(leaf
) + data_end
+ size_diff
, old_data_start
-data_end
, old_data_start
, data_end
);
1296 btrfs_memmove(root
, leaf
, btrfs_leaf_data(leaf
) +
1297 data_end
+ size_diff
, btrfs_leaf_data(leaf
) +
1298 data_end
, old_data_start
+ new_size
- data_end
);
1299 btrfs_set_item_size(leaf
->items
+ slot
, new_size
);
1300 btrfs_mark_buffer_dirty(leaf_buf
);
1303 if (btrfs_leaf_free_space(root
, leaf
) < 0)
1305 check_leaf(root
, path
, 0);
1309 int btrfs_extend_item(struct btrfs_trans_handle
*trans
, struct btrfs_root
1310 *root
, struct btrfs_path
*path
, u32 data_size
)
1315 struct btrfs_leaf
*leaf
;
1316 struct buffer_head
*leaf_buf
;
1318 unsigned int data_end
;
1319 unsigned int old_data
;
1320 unsigned int old_size
;
1323 slot_orig
= path
->slots
[0];
1324 leaf_buf
= path
->nodes
[0];
1325 leaf
= btrfs_buffer_leaf(leaf_buf
);
1327 nritems
= btrfs_header_nritems(&leaf
->header
);
1328 data_end
= leaf_data_end(root
, leaf
);
1330 if (btrfs_leaf_free_space(root
, leaf
) < data_size
)
1332 slot
= path
->slots
[0];
1333 old_data
= btrfs_item_end(leaf
->items
+ slot
);
1336 BUG_ON(slot
>= nritems
);
1339 * item0..itemN ... dataN.offset..dataN.size .. data0.size
1341 /* first correct the data pointers */
1342 for (i
= slot
; i
< nritems
; i
++) {
1343 u32 ioff
= btrfs_item_offset(leaf
->items
+ i
);
1344 btrfs_set_item_offset(leaf
->items
+ i
,
1347 /* shift the data */
1348 btrfs_memmove(root
, leaf
, btrfs_leaf_data(leaf
) +
1349 data_end
- data_size
, btrfs_leaf_data(leaf
) +
1350 data_end
, old_data
- data_end
);
1351 data_end
= old_data
;
1352 old_size
= btrfs_item_size(leaf
->items
+ slot
);
1353 btrfs_set_item_size(leaf
->items
+ slot
, old_size
+ data_size
);
1354 btrfs_mark_buffer_dirty(leaf_buf
);
1357 if (btrfs_leaf_free_space(root
, leaf
) < 0)
1359 check_leaf(root
, path
, 0);
1364 * Given a key and some data, insert an item into the tree.
1365 * This does all the path init required, making room in the tree if needed.
1367 int btrfs_insert_empty_item(struct btrfs_trans_handle
*trans
, struct btrfs_root
1368 *root
, struct btrfs_path
*path
, struct btrfs_key
1369 *cpu_key
, u32 data_size
)
1374 struct btrfs_leaf
*leaf
;
1375 struct buffer_head
*leaf_buf
;
1377 unsigned int data_end
;
1378 struct btrfs_disk_key disk_key
;
1380 btrfs_cpu_key_to_disk(&disk_key
, cpu_key
);
1382 /* create a root if there isn't one */
1385 ret
= btrfs_search_slot(trans
, root
, cpu_key
, path
, data_size
, 1);
1392 slot_orig
= path
->slots
[0];
1393 leaf_buf
= path
->nodes
[0];
1394 leaf
= btrfs_buffer_leaf(leaf_buf
);
1396 nritems
= btrfs_header_nritems(&leaf
->header
);
1397 data_end
= leaf_data_end(root
, leaf
);
1399 if (btrfs_leaf_free_space(root
, leaf
) <
1400 sizeof(struct btrfs_item
) + data_size
) {
1403 slot
= path
->slots
[0];
1405 if (slot
!= nritems
) {
1407 unsigned int old_data
= btrfs_item_end(leaf
->items
+ slot
);
1410 * item0..itemN ... dataN.offset..dataN.size .. data0.size
1412 /* first correct the data pointers */
1413 for (i
= slot
; i
< nritems
; i
++) {
1414 u32 ioff
= btrfs_item_offset(leaf
->items
+ i
);
1415 btrfs_set_item_offset(leaf
->items
+ i
,
1419 /* shift the items */
1420 btrfs_memmove(root
, leaf
, leaf
->items
+ slot
+ 1,
1422 (nritems
- slot
) * sizeof(struct btrfs_item
));
1424 /* shift the data */
1425 btrfs_memmove(root
, leaf
, btrfs_leaf_data(leaf
) +
1426 data_end
- data_size
, btrfs_leaf_data(leaf
) +
1427 data_end
, old_data
- data_end
);
1428 data_end
= old_data
;
1430 /* setup the item for the new data */
1431 btrfs_memcpy(root
, leaf
, &leaf
->items
[slot
].key
, &disk_key
,
1432 sizeof(struct btrfs_disk_key
));
1433 btrfs_set_item_offset(leaf
->items
+ slot
, data_end
- data_size
);
1434 btrfs_set_item_size(leaf
->items
+ slot
, data_size
);
1435 btrfs_set_header_nritems(&leaf
->header
, nritems
+ 1);
1436 btrfs_mark_buffer_dirty(leaf_buf
);
1440 ret
= fixup_low_keys(trans
, root
, path
, &disk_key
, 1);
1442 if (btrfs_leaf_free_space(root
, leaf
) < 0)
1444 check_leaf(root
, path
, 0);
1450 * Given a key and some data, insert an item into the tree.
1451 * This does all the path init required, making room in the tree if needed.
1453 int btrfs_insert_item(struct btrfs_trans_handle
*trans
, struct btrfs_root
1454 *root
, struct btrfs_key
*cpu_key
, void *data
, u32
1458 struct btrfs_path
*path
;
1461 path
= btrfs_alloc_path();
1463 btrfs_init_path(path
);
1464 ret
= btrfs_insert_empty_item(trans
, root
, path
, cpu_key
, data_size
);
1466 ptr
= btrfs_item_ptr(btrfs_buffer_leaf(path
->nodes
[0]),
1467 path
->slots
[0], u8
);
1468 btrfs_memcpy(root
, path
->nodes
[0]->b_data
,
1469 ptr
, data
, data_size
);
1470 btrfs_mark_buffer_dirty(path
->nodes
[0]);
1472 btrfs_release_path(root
, path
);
1473 btrfs_free_path(path
);
1478 * delete the pointer from a given node.
1480 * If the delete empties a node, the node is removed from the tree,
1481 * continuing all the way the root if required. The root is converted into
1482 * a leaf if all the nodes are emptied.
1484 static int del_ptr(struct btrfs_trans_handle
*trans
, struct btrfs_root
*root
,
1485 struct btrfs_path
*path
, int level
, int slot
)
1487 struct btrfs_node
*node
;
1488 struct buffer_head
*parent
= path
->nodes
[level
];
1493 node
= btrfs_buffer_node(parent
);
1494 nritems
= btrfs_header_nritems(&node
->header
);
1495 if (slot
!= nritems
-1) {
1496 btrfs_memmove(root
, node
, node
->ptrs
+ slot
,
1497 node
->ptrs
+ slot
+ 1,
1498 sizeof(struct btrfs_key_ptr
) *
1499 (nritems
- slot
- 1));
1502 btrfs_set_header_nritems(&node
->header
, nritems
);
1503 if (nritems
== 0 && parent
== root
->node
) {
1504 struct btrfs_header
*header
= btrfs_buffer_header(root
->node
);
1505 BUG_ON(btrfs_header_level(header
) != 1);
1506 /* just turn the root into a leaf and break */
1507 btrfs_set_header_level(header
, 0);
1508 } else if (slot
== 0) {
1509 wret
= fixup_low_keys(trans
, root
, path
, &node
->ptrs
[0].key
,
1514 btrfs_mark_buffer_dirty(parent
);
1519 * delete the item at the leaf level in path. If that empties
1520 * the leaf, remove it from the tree
1522 int btrfs_del_item(struct btrfs_trans_handle
*trans
, struct btrfs_root
*root
,
1523 struct btrfs_path
*path
)
1526 struct btrfs_leaf
*leaf
;
1527 struct buffer_head
*leaf_buf
;
1534 leaf_buf
= path
->nodes
[0];
1535 leaf
= btrfs_buffer_leaf(leaf_buf
);
1536 slot
= path
->slots
[0];
1537 doff
= btrfs_item_offset(leaf
->items
+ slot
);
1538 dsize
= btrfs_item_size(leaf
->items
+ slot
);
1539 nritems
= btrfs_header_nritems(&leaf
->header
);
1541 if (slot
!= nritems
- 1) {
1543 int data_end
= leaf_data_end(root
, leaf
);
1544 btrfs_memmove(root
, leaf
, btrfs_leaf_data(leaf
) +
1546 btrfs_leaf_data(leaf
) + data_end
,
1548 for (i
= slot
+ 1; i
< nritems
; i
++) {
1549 u32 ioff
= btrfs_item_offset(leaf
->items
+ i
);
1550 btrfs_set_item_offset(leaf
->items
+ i
, ioff
+ dsize
);
1552 btrfs_memmove(root
, leaf
, leaf
->items
+ slot
,
1553 leaf
->items
+ slot
+ 1,
1554 sizeof(struct btrfs_item
) *
1555 (nritems
- slot
- 1));
1557 btrfs_set_header_nritems(&leaf
->header
, nritems
- 1);
1559 /* delete the leaf if we've emptied it */
1561 if (leaf_buf
== root
->node
) {
1562 btrfs_set_header_level(&leaf
->header
, 0);
1564 clean_tree_block(trans
, root
, leaf_buf
);
1565 wait_on_buffer(leaf_buf
);
1566 wret
= del_ptr(trans
, root
, path
, 1, path
->slots
[1]);
1569 wret
= btrfs_free_extent(trans
, root
,
1570 bh_blocknr(leaf_buf
), 1, 1);
1575 int used
= leaf_space_used(leaf
, 0, nritems
);
1577 wret
= fixup_low_keys(trans
, root
, path
,
1578 &leaf
->items
[0].key
, 1);
1583 /* delete the leaf if it is mostly empty */
1584 if (used
< BTRFS_LEAF_DATA_SIZE(root
) / 3) {
1585 /* push_leaf_left fixes the path.
1586 * make sure the path still points to our leaf
1587 * for possible call to del_ptr below
1589 slot
= path
->slots
[1];
1591 wret
= push_leaf_left(trans
, root
, path
, 1);
1594 if (path
->nodes
[0] == leaf_buf
&&
1595 btrfs_header_nritems(&leaf
->header
)) {
1596 wret
= push_leaf_right(trans
, root
, path
, 1);
1600 if (btrfs_header_nritems(&leaf
->header
) == 0) {
1601 u64 blocknr
= bh_blocknr(leaf_buf
);
1602 clean_tree_block(trans
, root
, leaf_buf
);
1603 wait_on_buffer(leaf_buf
);
1604 wret
= del_ptr(trans
, root
, path
, 1, slot
);
1607 btrfs_block_release(root
, leaf_buf
);
1608 wret
= btrfs_free_extent(trans
, root
, blocknr
,
1613 btrfs_mark_buffer_dirty(leaf_buf
);
1614 btrfs_block_release(root
, leaf_buf
);
1617 btrfs_mark_buffer_dirty(leaf_buf
);
1624 * walk up the tree as far as required to find the next leaf.
1625 * returns 0 if it found something or 1 if there are no greater leaves.
1626 * returns < 0 on io errors.
1628 int btrfs_next_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
)
1633 struct buffer_head
*c
;
1634 struct btrfs_node
*c_node
;
1635 struct buffer_head
*next
= NULL
;
1637 while(level
< BTRFS_MAX_LEVEL
) {
1638 if (!path
->nodes
[level
])
1640 slot
= path
->slots
[level
] + 1;
1641 c
= path
->nodes
[level
];
1642 c_node
= btrfs_buffer_node(c
);
1643 if (slot
>= btrfs_header_nritems(&c_node
->header
)) {
1647 blocknr
= btrfs_node_blockptr(c_node
, slot
);
1649 btrfs_block_release(root
, next
);
1650 next
= read_tree_block(root
, blocknr
);
1653 path
->slots
[level
] = slot
;
1656 c
= path
->nodes
[level
];
1657 btrfs_block_release(root
, c
);
1658 path
->nodes
[level
] = next
;
1659 path
->slots
[level
] = 0;
1662 next
= read_tree_block(root
,
1663 btrfs_node_blockptr(btrfs_buffer_node(next
), 0));
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