3 #include "kerncompat.h"
4 #include "radix-tree.h"
7 #include "print-tree.h"
9 static int split_node(struct btrfs_root
*root
, struct btrfs_path
*path
,
11 static int split_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
,
13 static int push_node_left(struct btrfs_root
*root
, struct btrfs_buffer
*dst
,
14 struct btrfs_buffer
*src
);
15 static int balance_node_right(struct btrfs_root
*root
,
16 struct btrfs_buffer
*dst_buf
,
17 struct btrfs_buffer
*src_buf
);
18 static int del_ptr(struct btrfs_root
*root
, struct btrfs_path
*path
, int level
,
21 inline void btrfs_init_path(struct btrfs_path
*p
)
23 memset(p
, 0, sizeof(*p
));
26 void btrfs_release_path(struct btrfs_root
*root
, struct btrfs_path
*p
)
29 for (i
= 0; i
< BTRFS_MAX_LEVEL
; i
++) {
32 btrfs_block_release(root
, p
->nodes
[i
]);
34 memset(p
, 0, sizeof(*p
));
37 static int btrfs_cow_block(struct btrfs_root
*root
,
38 struct btrfs_buffer
*buf
,
39 struct btrfs_buffer
*parent
,
41 struct btrfs_buffer
**cow_ret
)
43 struct btrfs_buffer
*cow
;
45 if (!list_empty(&buf
->dirty
)) {
49 cow
= btrfs_alloc_free_block(root
);
50 memcpy(&cow
->node
, &buf
->node
, sizeof(buf
->node
));
51 btrfs_set_header_blocknr(&cow
->node
.header
, cow
->blocknr
);
53 btrfs_inc_ref(root
, buf
);
54 if (buf
== root
->node
) {
57 if (buf
!= root
->commit_root
)
58 btrfs_free_extent(root
, buf
->blocknr
, 1);
59 btrfs_block_release(root
, buf
);
61 btrfs_set_node_blockptr(&parent
->node
, parent_slot
,
63 BUG_ON(list_empty(&parent
->dirty
));
64 btrfs_free_extent(root
, buf
->blocknr
, 1);
66 btrfs_block_release(root
, buf
);
71 * The leaf data grows from end-to-front in the node.
72 * this returns the address of the start of the last item,
73 * which is the stop of the leaf data stack
75 static inline unsigned int leaf_data_end(struct btrfs_leaf
*leaf
)
77 u32 nr
= btrfs_header_nritems(&leaf
->header
);
79 return sizeof(leaf
->data
);
80 return btrfs_item_offset(leaf
->items
+ nr
- 1);
84 * The space between the end of the leaf items and
85 * the start of the leaf data. IOW, how much room
86 * the leaf has left for both items and data
88 int btrfs_leaf_free_space(struct btrfs_leaf
*leaf
)
90 int data_end
= leaf_data_end(leaf
);
91 int nritems
= btrfs_header_nritems(&leaf
->header
);
92 char *items_end
= (char *)(leaf
->items
+ nritems
+ 1);
93 return (char *)(leaf
->data
+ data_end
) - (char *)items_end
;
97 * compare two keys in a memcmp fashion
99 static int comp_keys(struct btrfs_disk_key
*disk
, struct btrfs_key
*k2
)
103 btrfs_disk_key_to_cpu(&k1
, disk
);
105 if (k1
.objectid
> k2
->objectid
)
107 if (k1
.objectid
< k2
->objectid
)
109 if (k1
.flags
> k2
->flags
)
111 if (k1
.flags
< k2
->flags
)
113 if (k1
.offset
> k2
->offset
)
115 if (k1
.offset
< k2
->offset
)
120 static int check_node(struct btrfs_path
*path
, int level
)
123 struct btrfs_node
*parent
= NULL
;
124 struct btrfs_node
*node
= &path
->nodes
[level
]->node
;
126 u32 nritems
= btrfs_header_nritems(&node
->header
);
128 if (path
->nodes
[level
+ 1])
129 parent
= &path
->nodes
[level
+ 1]->node
;
130 parent_slot
= path
->slots
[level
+ 1];
131 BUG_ON(nritems
== 0);
133 struct btrfs_disk_key
*parent_key
;
134 parent_key
= &parent
->keys
[parent_slot
];
135 BUG_ON(memcmp(parent_key
, node
->keys
,
136 sizeof(struct btrfs_disk_key
)));
137 BUG_ON(btrfs_node_blockptr(parent
, parent_slot
) !=
138 btrfs_header_blocknr(&node
->header
));
140 BUG_ON(nritems
> NODEPTRS_PER_BLOCK
);
141 for (i
= 0; nritems
> 1 && i
< nritems
- 2; i
++) {
142 struct btrfs_key cpukey
;
143 btrfs_disk_key_to_cpu(&cpukey
, &node
->keys
[i
+ 1]);
144 BUG_ON(comp_keys(&node
->keys
[i
], &cpukey
) >= 0);
149 static int check_leaf(struct btrfs_path
*path
, int level
)
152 struct btrfs_leaf
*leaf
= &path
->nodes
[level
]->leaf
;
153 struct btrfs_node
*parent
= NULL
;
155 u32 nritems
= btrfs_header_nritems(&leaf
->header
);
157 if (path
->nodes
[level
+ 1])
158 parent
= &path
->nodes
[level
+ 1]->node
;
159 parent_slot
= path
->slots
[level
+ 1];
160 BUG_ON(btrfs_leaf_free_space(leaf
) < 0);
166 struct btrfs_disk_key
*parent_key
;
167 parent_key
= &parent
->keys
[parent_slot
];
168 BUG_ON(memcmp(parent_key
, &leaf
->items
[0].key
,
169 sizeof(struct btrfs_disk_key
)));
170 BUG_ON(btrfs_node_blockptr(parent
, parent_slot
) !=
171 btrfs_header_blocknr(&leaf
->header
));
173 for (i
= 0; nritems
> 1 && i
< nritems
- 2; i
++) {
174 struct btrfs_key cpukey
;
175 btrfs_disk_key_to_cpu(&cpukey
, &leaf
->items
[i
+ 1].key
);
176 BUG_ON(comp_keys(&leaf
->items
[i
].key
,
178 BUG_ON(btrfs_item_offset(leaf
->items
+ i
) !=
179 btrfs_item_end(leaf
->items
+ i
+ 1));
181 BUG_ON(btrfs_item_offset(leaf
->items
+ i
) +
182 btrfs_item_size(leaf
->items
+ i
) !=
189 static int check_block(struct btrfs_path
*path
, int level
)
192 return check_leaf(path
, level
);
193 return check_node(path
, level
);
197 * search for key in the array p. items p are item_size apart
198 * and there are 'max' items in p
199 * the slot in the array is returned via slot, and it points to
200 * the place where you would insert key if it is not found in
203 * slot may point to max if the key is bigger than all of the keys
205 static int generic_bin_search(char *p
, int item_size
, struct btrfs_key
*key
,
212 struct btrfs_disk_key
*tmp
;
215 mid
= (low
+ high
) / 2;
216 tmp
= (struct btrfs_disk_key
*)(p
+ mid
* item_size
);
217 ret
= comp_keys(tmp
, key
);
233 * simple bin_search frontend that does the right thing for
236 static int bin_search(struct btrfs_node
*c
, struct btrfs_key
*key
, int *slot
)
238 if (btrfs_is_leaf(c
)) {
239 struct btrfs_leaf
*l
= (struct btrfs_leaf
*)c
;
240 return generic_bin_search((void *)l
->items
,
241 sizeof(struct btrfs_item
),
242 key
, btrfs_header_nritems(&c
->header
),
245 return generic_bin_search((void *)c
->keys
,
246 sizeof(struct btrfs_disk_key
),
247 key
, btrfs_header_nritems(&c
->header
),
253 static struct btrfs_buffer
*read_node_slot(struct btrfs_root
*root
,
254 struct btrfs_buffer
*parent_buf
,
257 struct btrfs_node
*node
= &parent_buf
->node
;
260 if (slot
>= btrfs_header_nritems(&node
->header
))
262 return read_tree_block(root
, btrfs_node_blockptr(node
, slot
));
265 static int balance_level(struct btrfs_root
*root
, struct btrfs_path
*path
,
268 struct btrfs_buffer
*right_buf
;
269 struct btrfs_buffer
*mid_buf
;
270 struct btrfs_buffer
*left_buf
;
271 struct btrfs_buffer
*parent_buf
= NULL
;
272 struct btrfs_node
*right
= NULL
;
273 struct btrfs_node
*mid
;
274 struct btrfs_node
*left
= NULL
;
275 struct btrfs_node
*parent
= NULL
;
279 int orig_slot
= path
->slots
[level
];
285 mid_buf
= path
->nodes
[level
];
286 mid
= &mid_buf
->node
;
287 orig_ptr
= btrfs_node_blockptr(mid
, orig_slot
);
289 if (level
< BTRFS_MAX_LEVEL
- 1)
290 parent_buf
= path
->nodes
[level
+ 1];
291 pslot
= path
->slots
[level
+ 1];
294 struct btrfs_buffer
*child
;
295 u64 blocknr
= mid_buf
->blocknr
;
297 if (btrfs_header_nritems(&mid
->header
) != 1)
300 /* promote the child to a root */
301 child
= read_node_slot(root
, mid_buf
, 0);
304 path
->nodes
[level
] = NULL
;
305 /* once for the path */
306 btrfs_block_release(root
, mid_buf
);
307 /* once for the root ptr */
308 btrfs_block_release(root
, mid_buf
);
309 clean_tree_block(root
, mid_buf
);
310 return btrfs_free_extent(root
, blocknr
, 1);
312 parent
= &parent_buf
->node
;
314 if (btrfs_header_nritems(&mid
->header
) > NODEPTRS_PER_BLOCK
/ 4)
317 left_buf
= read_node_slot(root
, parent_buf
, pslot
- 1);
318 right_buf
= read_node_slot(root
, parent_buf
, pslot
+ 1);
320 /* first, try to make some room in the middle buffer */
322 btrfs_cow_block(root
, left_buf
, parent_buf
,
323 pslot
- 1, &left_buf
);
324 left
= &left_buf
->node
;
325 orig_slot
+= btrfs_header_nritems(&left
->header
);
326 wret
= push_node_left(root
, left_buf
, mid_buf
);
332 * then try to empty the right most buffer into the middle
335 btrfs_cow_block(root
, right_buf
, parent_buf
,
336 pslot
+ 1, &right_buf
);
337 right
= &right_buf
->node
;
338 wret
= push_node_left(root
, mid_buf
, right_buf
);
341 if (btrfs_header_nritems(&right
->header
) == 0) {
342 u64 blocknr
= right_buf
->blocknr
;
343 btrfs_block_release(root
, right_buf
);
344 clean_tree_block(root
, right_buf
);
347 wret
= del_ptr(root
, path
, level
+ 1, pslot
+ 1);
350 wret
= btrfs_free_extent(root
, blocknr
, 1);
354 memcpy(parent
->keys
+ pslot
+ 1, right
->keys
,
355 sizeof(struct btrfs_disk_key
));
356 BUG_ON(list_empty(&parent_buf
->dirty
));
359 if (btrfs_header_nritems(&mid
->header
) == 1) {
361 * we're not allowed to leave a node with one item in the
362 * tree during a delete. A deletion from lower in the tree
363 * could try to delete the only pointer in this node.
364 * So, pull some keys from the left.
365 * There has to be a left pointer at this point because
366 * otherwise we would have pulled some pointers from the
370 wret
= balance_node_right(root
, mid_buf
, left_buf
);
375 if (btrfs_header_nritems(&mid
->header
) == 0) {
376 /* we've managed to empty the middle node, drop it */
377 u64 blocknr
= mid_buf
->blocknr
;
378 btrfs_block_release(root
, mid_buf
);
379 clean_tree_block(root
, mid_buf
);
382 wret
= del_ptr(root
, path
, level
+ 1, pslot
);
385 wret
= btrfs_free_extent(root
, blocknr
, 1);
389 /* update the parent key to reflect our changes */
390 memcpy(parent
->keys
+ pslot
, mid
->keys
,
391 sizeof(struct btrfs_disk_key
));
392 BUG_ON(list_empty(&parent_buf
->dirty
));
395 /* update the path */
397 if (btrfs_header_nritems(&left
->header
) > orig_slot
) {
398 left_buf
->count
++; // released below
399 path
->nodes
[level
] = left_buf
;
400 path
->slots
[level
+ 1] -= 1;
401 path
->slots
[level
] = orig_slot
;
403 btrfs_block_release(root
, mid_buf
);
405 orig_slot
-= btrfs_header_nritems(&left
->header
);
406 path
->slots
[level
] = orig_slot
;
409 /* double check we haven't messed things up */
410 check_block(path
, level
);
411 if (orig_ptr
!= btrfs_node_blockptr(&path
->nodes
[level
]->node
,
416 btrfs_block_release(root
, right_buf
);
418 btrfs_block_release(root
, left_buf
);
423 * look for key in the tree. path is filled in with nodes along the way
424 * if key is found, we return zero and you can find the item in the leaf
425 * level of the path (level 0)
427 * If the key isn't found, the path points to the slot where it should
428 * be inserted, and 1 is returned. If there are other errors during the
429 * search a negative error number is returned.
431 * if ins_len > 0, nodes and leaves will be split as we walk down the
432 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
435 int btrfs_search_slot(struct btrfs_root
*root
, struct btrfs_key
*key
,
436 struct btrfs_path
*p
, int ins_len
, int cow
)
438 struct btrfs_buffer
*b
;
439 struct btrfs_buffer
*cow_buf
;
440 struct btrfs_node
*c
;
449 level
= btrfs_header_level(&b
->node
.header
);
452 wret
= btrfs_cow_block(root
, b
, p
->nodes
[level
+ 1],
453 p
->slots
[level
+ 1], &cow_buf
);
456 BUG_ON(!cow
&& ins_len
);
459 ret
= check_block(p
, level
);
462 ret
= bin_search(c
, key
, &slot
);
463 if (!btrfs_is_leaf(c
)) {
466 p
->slots
[level
] = slot
;
467 if (ins_len
> 0 && btrfs_header_nritems(&c
->header
) ==
468 NODEPTRS_PER_BLOCK
) {
469 int sret
= split_node(root
, p
, level
);
475 slot
= p
->slots
[level
];
476 } else if (ins_len
< 0) {
477 int sret
= balance_level(root
, p
, level
);
484 slot
= p
->slots
[level
];
485 BUG_ON(btrfs_header_nritems(&c
->header
) == 1);
487 b
= read_tree_block(root
, btrfs_node_blockptr(c
, slot
));
489 struct btrfs_leaf
*l
= (struct btrfs_leaf
*)c
;
490 p
->slots
[level
] = slot
;
491 if (ins_len
> 0 && btrfs_leaf_free_space(l
) <
492 sizeof(struct btrfs_item
) + ins_len
) {
493 int sret
= split_leaf(root
, p
, ins_len
);
498 BUG_ON(root
->node
->count
== 1);
502 BUG_ON(root
->node
->count
== 1);
507 * adjust the pointers going up the tree, starting at level
508 * making sure the right key of each node is points to 'key'.
509 * This is used after shifting pointers to the left, so it stops
510 * fixing up pointers when a given leaf/node is not in slot 0 of the
513 * If this fails to write a tree block, it returns -1, but continues
514 * fixing up the blocks in ram so the tree is consistent.
516 static int fixup_low_keys(struct btrfs_root
*root
,
517 struct btrfs_path
*path
, struct btrfs_disk_key
*key
,
522 for (i
= level
; i
< BTRFS_MAX_LEVEL
; i
++) {
523 struct btrfs_node
*t
;
524 int tslot
= path
->slots
[i
];
527 t
= &path
->nodes
[i
]->node
;
528 memcpy(t
->keys
+ tslot
, key
, sizeof(*key
));
529 BUG_ON(list_empty(&path
->nodes
[i
]->dirty
));
537 * try to push data from one node into the next node left in the
540 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
541 * error, and > 0 if there was no room in the left hand block.
543 static int push_node_left(struct btrfs_root
*root
, struct btrfs_buffer
*dst_buf
,
544 struct btrfs_buffer
*src_buf
)
546 struct btrfs_node
*src
= &src_buf
->node
;
547 struct btrfs_node
*dst
= &dst_buf
->node
;
553 src_nritems
= btrfs_header_nritems(&src
->header
);
554 dst_nritems
= btrfs_header_nritems(&dst
->header
);
555 push_items
= NODEPTRS_PER_BLOCK
- dst_nritems
;
556 if (push_items
<= 0) {
560 if (src_nritems
< push_items
)
561 push_items
= src_nritems
;
563 memcpy(dst
->keys
+ dst_nritems
, src
->keys
,
564 push_items
* sizeof(struct btrfs_disk_key
));
565 memcpy(dst
->blockptrs
+ dst_nritems
, src
->blockptrs
,
566 push_items
* sizeof(u64
));
567 if (push_items
< src_nritems
) {
568 memmove(src
->keys
, src
->keys
+ push_items
,
569 (src_nritems
- push_items
) *
570 sizeof(struct btrfs_disk_key
));
571 memmove(src
->blockptrs
, src
->blockptrs
+ push_items
,
572 (src_nritems
- push_items
) * sizeof(u64
));
574 btrfs_set_header_nritems(&src
->header
, src_nritems
- push_items
);
575 btrfs_set_header_nritems(&dst
->header
, dst_nritems
+ push_items
);
576 BUG_ON(list_empty(&src_buf
->dirty
));
577 BUG_ON(list_empty(&dst_buf
->dirty
));
582 * try to push data from one node into the next node right in the
585 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
586 * error, and > 0 if there was no room in the right hand block.
588 * this will only push up to 1/2 the contents of the left node over
590 static int balance_node_right(struct btrfs_root
*root
,
591 struct btrfs_buffer
*dst_buf
,
592 struct btrfs_buffer
*src_buf
)
594 struct btrfs_node
*src
= &src_buf
->node
;
595 struct btrfs_node
*dst
= &dst_buf
->node
;
602 src_nritems
= btrfs_header_nritems(&src
->header
);
603 dst_nritems
= btrfs_header_nritems(&dst
->header
);
604 push_items
= NODEPTRS_PER_BLOCK
- dst_nritems
;
605 if (push_items
<= 0) {
609 max_push
= src_nritems
/ 2 + 1;
610 /* don't try to empty the node */
611 if (max_push
> src_nritems
)
613 if (max_push
< push_items
)
614 push_items
= max_push
;
616 memmove(dst
->keys
+ push_items
, dst
->keys
,
617 dst_nritems
* sizeof(struct btrfs_disk_key
));
618 memmove(dst
->blockptrs
+ push_items
, dst
->blockptrs
,
619 dst_nritems
* sizeof(u64
));
620 memcpy(dst
->keys
, src
->keys
+ src_nritems
- push_items
,
621 push_items
* sizeof(struct btrfs_disk_key
));
622 memcpy(dst
->blockptrs
, src
->blockptrs
+ src_nritems
- push_items
,
623 push_items
* sizeof(u64
));
625 btrfs_set_header_nritems(&src
->header
, src_nritems
- push_items
);
626 btrfs_set_header_nritems(&dst
->header
, dst_nritems
+ push_items
);
628 BUG_ON(list_empty(&src_buf
->dirty
));
629 BUG_ON(list_empty(&dst_buf
->dirty
));
634 * helper function to insert a new root level in the tree.
635 * A new node is allocated, and a single item is inserted to
636 * point to the existing root
638 * returns zero on success or < 0 on failure.
640 static int insert_new_root(struct btrfs_root
*root
,
641 struct btrfs_path
*path
, int level
)
643 struct btrfs_buffer
*t
;
644 struct btrfs_node
*lower
;
645 struct btrfs_node
*c
;
646 struct btrfs_disk_key
*lower_key
;
648 BUG_ON(path
->nodes
[level
]);
649 BUG_ON(path
->nodes
[level
-1] != root
->node
);
651 t
= btrfs_alloc_free_block(root
);
653 memset(c
, 0, sizeof(c
));
654 btrfs_set_header_nritems(&c
->header
, 1);
655 btrfs_set_header_level(&c
->header
, level
);
656 btrfs_set_header_blocknr(&c
->header
, t
->blocknr
);
657 btrfs_set_header_parentid(&c
->header
,
658 btrfs_header_parentid(&root
->node
->node
.header
));
659 lower
= &path
->nodes
[level
-1]->node
;
660 if (btrfs_is_leaf(lower
))
661 lower_key
= &((struct btrfs_leaf
*)lower
)->items
[0].key
;
663 lower_key
= lower
->keys
;
664 memcpy(c
->keys
, lower_key
, sizeof(struct btrfs_disk_key
));
665 btrfs_set_node_blockptr(c
, 0, path
->nodes
[level
- 1]->blocknr
);
666 /* the super has an extra ref to root->node */
667 btrfs_block_release(root
, root
->node
);
670 path
->nodes
[level
] = t
;
671 path
->slots
[level
] = 0;
676 * worker function to insert a single pointer in a node.
677 * the node should have enough room for the pointer already
679 * slot and level indicate where you want the key to go, and
680 * blocknr is the block the key points to.
682 * returns zero on success and < 0 on any error
684 static int insert_ptr(struct btrfs_root
*root
,
685 struct btrfs_path
*path
, struct btrfs_disk_key
*key
,
686 u64 blocknr
, int slot
, int level
)
688 struct btrfs_node
*lower
;
691 BUG_ON(!path
->nodes
[level
]);
692 lower
= &path
->nodes
[level
]->node
;
693 nritems
= btrfs_header_nritems(&lower
->header
);
696 if (nritems
== NODEPTRS_PER_BLOCK
)
698 if (slot
!= nritems
) {
699 memmove(lower
->keys
+ slot
+ 1, lower
->keys
+ slot
,
700 (nritems
- slot
) * sizeof(struct btrfs_disk_key
));
701 memmove(lower
->blockptrs
+ slot
+ 1, lower
->blockptrs
+ slot
,
702 (nritems
- slot
) * sizeof(u64
));
704 memcpy(lower
->keys
+ slot
, key
, sizeof(struct btrfs_disk_key
));
705 btrfs_set_node_blockptr(lower
, slot
, blocknr
);
706 btrfs_set_header_nritems(&lower
->header
, nritems
+ 1);
707 if (lower
->keys
[1].objectid
== 0)
709 BUG_ON(list_empty(&path
->nodes
[level
]->dirty
));
714 * split the node at the specified level in path in two.
715 * The path is corrected to point to the appropriate node after the split
717 * Before splitting this tries to make some room in the node by pushing
718 * left and right, if either one works, it returns right away.
720 * returns 0 on success and < 0 on failure
722 static int split_node(struct btrfs_root
*root
, struct btrfs_path
*path
,
725 struct btrfs_buffer
*t
;
726 struct btrfs_node
*c
;
727 struct btrfs_buffer
*split_buffer
;
728 struct btrfs_node
*split
;
734 t
= path
->nodes
[level
];
736 if (t
== root
->node
) {
737 /* trying to split the root, lets make a new one */
738 ret
= insert_new_root(root
, path
, level
+ 1);
742 c_nritems
= btrfs_header_nritems(&c
->header
);
743 split_buffer
= btrfs_alloc_free_block(root
);
744 split
= &split_buffer
->node
;
745 btrfs_set_header_flags(&split
->header
, btrfs_header_flags(&c
->header
));
746 btrfs_set_header_blocknr(&split
->header
, split_buffer
->blocknr
);
747 btrfs_set_header_parentid(&split
->header
,
748 btrfs_header_parentid(&root
->node
->node
.header
));
749 mid
= (c_nritems
+ 1) / 2;
750 memcpy(split
->keys
, c
->keys
+ mid
,
751 (c_nritems
- mid
) * sizeof(struct btrfs_disk_key
));
752 memcpy(split
->blockptrs
, c
->blockptrs
+ mid
,
753 (c_nritems
- mid
) * sizeof(u64
));
754 btrfs_set_header_nritems(&split
->header
, c_nritems
- mid
);
755 btrfs_set_header_nritems(&c
->header
, mid
);
758 BUG_ON(list_empty(&t
->dirty
));
759 wret
= insert_ptr(root
, path
, split
->keys
, split_buffer
->blocknr
,
760 path
->slots
[level
+ 1] + 1, level
+ 1);
764 if (path
->slots
[level
] >= mid
) {
765 path
->slots
[level
] -= mid
;
766 btrfs_block_release(root
, t
);
767 path
->nodes
[level
] = split_buffer
;
768 path
->slots
[level
+ 1] += 1;
770 btrfs_block_release(root
, split_buffer
);
776 * how many bytes are required to store the items in a leaf. start
777 * and nr indicate which items in the leaf to check. This totals up the
778 * space used both by the item structs and the item data
780 static int leaf_space_used(struct btrfs_leaf
*l
, int start
, int nr
)
783 int end
= start
+ nr
- 1;
787 data_len
= btrfs_item_end(l
->items
+ start
);
788 data_len
= data_len
- btrfs_item_offset(l
->items
+ end
);
789 data_len
+= sizeof(struct btrfs_item
) * nr
;
794 * push some data in the path leaf to the right, trying to free up at
795 * least data_size bytes. returns zero if the push worked, nonzero otherwise
797 * returns 1 if the push failed because the other node didn't have enough
798 * room, 0 if everything worked out and < 0 if there were major errors.
800 static int push_leaf_right(struct btrfs_root
*root
, struct btrfs_path
*path
,
803 struct btrfs_buffer
*left_buf
= path
->nodes
[0];
804 struct btrfs_leaf
*left
= &left_buf
->leaf
;
805 struct btrfs_leaf
*right
;
806 struct btrfs_buffer
*right_buf
;
807 struct btrfs_buffer
*upper
;
813 struct btrfs_item
*item
;
817 slot
= path
->slots
[1];
818 if (!path
->nodes
[1]) {
821 upper
= path
->nodes
[1];
822 if (slot
>= btrfs_header_nritems(&upper
->node
.header
) - 1) {
825 right_buf
= read_tree_block(root
, btrfs_node_blockptr(&upper
->node
,
827 right
= &right_buf
->leaf
;
828 free_space
= btrfs_leaf_free_space(right
);
829 if (free_space
< data_size
+ sizeof(struct btrfs_item
)) {
830 btrfs_block_release(root
, right_buf
);
833 /* cow and double check */
834 btrfs_cow_block(root
, right_buf
, upper
, slot
+ 1, &right_buf
);
835 right
= &right_buf
->leaf
;
836 free_space
= btrfs_leaf_free_space(right
);
837 if (free_space
< data_size
+ sizeof(struct btrfs_item
)) {
838 btrfs_block_release(root
, right_buf
);
842 left_nritems
= btrfs_header_nritems(&left
->header
);
843 for (i
= left_nritems
- 1; i
>= 0; i
--) {
844 item
= left
->items
+ i
;
845 if (path
->slots
[0] == i
)
846 push_space
+= data_size
+ sizeof(*item
);
847 if (btrfs_item_size(item
) + sizeof(*item
) + push_space
>
851 push_space
+= btrfs_item_size(item
) + sizeof(*item
);
853 if (push_items
== 0) {
854 btrfs_block_release(root
, right_buf
);
857 right_nritems
= btrfs_header_nritems(&right
->header
);
858 /* push left to right */
859 push_space
= btrfs_item_end(left
->items
+ left_nritems
- push_items
);
860 push_space
-= leaf_data_end(left
);
861 /* make room in the right data area */
862 memmove(right
->data
+ leaf_data_end(right
) - push_space
,
863 right
->data
+ leaf_data_end(right
),
864 LEAF_DATA_SIZE
- leaf_data_end(right
));
865 /* copy from the left data area */
866 memcpy(right
->data
+ LEAF_DATA_SIZE
- push_space
,
867 left
->data
+ leaf_data_end(left
),
869 memmove(right
->items
+ push_items
, right
->items
,
870 right_nritems
* sizeof(struct btrfs_item
));
871 /* copy the items from left to right */
872 memcpy(right
->items
, left
->items
+ left_nritems
- push_items
,
873 push_items
* sizeof(struct btrfs_item
));
875 /* update the item pointers */
876 right_nritems
+= push_items
;
877 btrfs_set_header_nritems(&right
->header
, right_nritems
);
878 push_space
= LEAF_DATA_SIZE
;
879 for (i
= 0; i
< right_nritems
; i
++) {
880 btrfs_set_item_offset(right
->items
+ i
, push_space
-
881 btrfs_item_size(right
->items
+ i
));
882 push_space
= btrfs_item_offset(right
->items
+ i
);
884 left_nritems
-= push_items
;
885 btrfs_set_header_nritems(&left
->header
, left_nritems
);
887 BUG_ON(list_empty(&left_buf
->dirty
));
888 BUG_ON(list_empty(&right_buf
->dirty
));
889 memcpy(upper
->node
.keys
+ slot
+ 1,
890 &right
->items
[0].key
, sizeof(struct btrfs_disk_key
));
891 BUG_ON(list_empty(&upper
->dirty
));
893 /* then fixup the leaf pointer in the path */
894 if (path
->slots
[0] >= left_nritems
) {
895 path
->slots
[0] -= left_nritems
;
896 btrfs_block_release(root
, path
->nodes
[0]);
897 path
->nodes
[0] = right_buf
;
900 btrfs_block_release(root
, right_buf
);
905 * push some data in the path leaf to the left, trying to free up at
906 * least data_size bytes. returns zero if the push worked, nonzero otherwise
908 static int push_leaf_left(struct btrfs_root
*root
, struct btrfs_path
*path
,
911 struct btrfs_buffer
*right_buf
= path
->nodes
[0];
912 struct btrfs_leaf
*right
= &right_buf
->leaf
;
913 struct btrfs_buffer
*t
;
914 struct btrfs_leaf
*left
;
920 struct btrfs_item
*item
;
921 u32 old_left_nritems
;
925 slot
= path
->slots
[1];
929 if (!path
->nodes
[1]) {
932 t
= read_tree_block(root
, btrfs_node_blockptr(&path
->nodes
[1]->node
,
935 free_space
= btrfs_leaf_free_space(left
);
936 if (free_space
< data_size
+ sizeof(struct btrfs_item
)) {
937 btrfs_block_release(root
, t
);
941 /* cow and double check */
942 btrfs_cow_block(root
, t
, path
->nodes
[1], slot
- 1, &t
);
944 free_space
= btrfs_leaf_free_space(left
);
945 if (free_space
< data_size
+ sizeof(struct btrfs_item
)) {
946 btrfs_block_release(root
, t
);
950 for (i
= 0; i
< btrfs_header_nritems(&right
->header
); i
++) {
951 item
= right
->items
+ i
;
952 if (path
->slots
[0] == i
)
953 push_space
+= data_size
+ sizeof(*item
);
954 if (btrfs_item_size(item
) + sizeof(*item
) + push_space
>
958 push_space
+= btrfs_item_size(item
) + sizeof(*item
);
960 if (push_items
== 0) {
961 btrfs_block_release(root
, t
);
964 /* push data from right to left */
965 memcpy(left
->items
+ btrfs_header_nritems(&left
->header
),
966 right
->items
, push_items
* sizeof(struct btrfs_item
));
967 push_space
= LEAF_DATA_SIZE
-
968 btrfs_item_offset(right
->items
+ push_items
-1);
969 memcpy(left
->data
+ leaf_data_end(left
) - push_space
,
970 right
->data
+ btrfs_item_offset(right
->items
+ push_items
- 1),
972 old_left_nritems
= btrfs_header_nritems(&left
->header
);
973 BUG_ON(old_left_nritems
< 0);
975 for (i
= old_left_nritems
; i
< old_left_nritems
+ push_items
; i
++) {
976 u16 ioff
= btrfs_item_offset(left
->items
+ i
);
977 btrfs_set_item_offset(left
->items
+ i
, ioff
- (LEAF_DATA_SIZE
-
978 btrfs_item_offset(left
->items
+
979 old_left_nritems
- 1)));
981 btrfs_set_header_nritems(&left
->header
, old_left_nritems
+ push_items
);
983 /* fixup right node */
984 push_space
= btrfs_item_offset(right
->items
+ push_items
- 1) -
985 leaf_data_end(right
);
986 memmove(right
->data
+ LEAF_DATA_SIZE
- push_space
, right
->data
+
987 leaf_data_end(right
), push_space
);
988 memmove(right
->items
, right
->items
+ push_items
,
989 (btrfs_header_nritems(&right
->header
) - push_items
) *
990 sizeof(struct btrfs_item
));
991 btrfs_set_header_nritems(&right
->header
,
992 btrfs_header_nritems(&right
->header
) -
994 push_space
= LEAF_DATA_SIZE
;
996 for (i
= 0; i
< btrfs_header_nritems(&right
->header
); i
++) {
997 btrfs_set_item_offset(right
->items
+ i
, push_space
-
998 btrfs_item_size(right
->items
+ i
));
999 push_space
= btrfs_item_offset(right
->items
+ i
);
1002 BUG_ON(list_empty(&t
->dirty
));
1003 BUG_ON(list_empty(&right_buf
->dirty
));
1005 wret
= fixup_low_keys(root
, path
, &right
->items
[0].key
, 1);
1009 /* then fixup the leaf pointer in the path */
1010 if (path
->slots
[0] < push_items
) {
1011 path
->slots
[0] += old_left_nritems
;
1012 btrfs_block_release(root
, path
->nodes
[0]);
1014 path
->slots
[1] -= 1;
1016 btrfs_block_release(root
, t
);
1017 path
->slots
[0] -= push_items
;
1019 BUG_ON(path
->slots
[0] < 0);
1024 * split the path's leaf in two, making sure there is at least data_size
1025 * available for the resulting leaf level of the path.
1027 * returns 0 if all went well and < 0 on failure.
1029 static int split_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
,
1032 struct btrfs_buffer
*l_buf
;
1033 struct btrfs_leaf
*l
;
1037 struct btrfs_leaf
*right
;
1038 struct btrfs_buffer
*right_buffer
;
1039 int space_needed
= data_size
+ sizeof(struct btrfs_item
);
1046 wret
= push_leaf_left(root
, path
, data_size
);
1050 wret
= push_leaf_right(root
, path
, data_size
);
1055 l_buf
= path
->nodes
[0];
1058 /* did the pushes work? */
1059 if (btrfs_leaf_free_space(l
) >= sizeof(struct btrfs_item
) + data_size
)
1062 if (!path
->nodes
[1]) {
1063 ret
= insert_new_root(root
, path
, 1);
1067 slot
= path
->slots
[0];
1068 nritems
= btrfs_header_nritems(&l
->header
);
1069 mid
= (nritems
+ 1)/ 2;
1070 right_buffer
= btrfs_alloc_free_block(root
);
1071 BUG_ON(!right_buffer
);
1072 BUG_ON(mid
== nritems
);
1073 right
= &right_buffer
->leaf
;
1074 memset(right
, 0, sizeof(*right
));
1076 /* FIXME, just alloc a new leaf here */
1077 if (leaf_space_used(l
, mid
, nritems
- mid
) + space_needed
>
1081 /* FIXME, just alloc a new leaf here */
1082 if (leaf_space_used(l
, 0, mid
+ 1) + space_needed
>
1086 btrfs_set_header_nritems(&right
->header
, nritems
- mid
);
1087 btrfs_set_header_blocknr(&right
->header
, right_buffer
->blocknr
);
1088 btrfs_set_header_level(&right
->header
, 0);
1089 btrfs_set_header_parentid(&right
->header
,
1090 btrfs_header_parentid(&root
->node
->node
.header
));
1091 data_copy_size
= btrfs_item_end(l
->items
+ mid
) - leaf_data_end(l
);
1092 memcpy(right
->items
, l
->items
+ mid
,
1093 (nritems
- mid
) * sizeof(struct btrfs_item
));
1094 memcpy(right
->data
+ LEAF_DATA_SIZE
- data_copy_size
,
1095 l
->data
+ leaf_data_end(l
), data_copy_size
);
1096 rt_data_off
= LEAF_DATA_SIZE
- btrfs_item_end(l
->items
+ mid
);
1098 for (i
= 0; i
< btrfs_header_nritems(&right
->header
); i
++) {
1099 u16 ioff
= btrfs_item_offset(right
->items
+ i
);
1100 btrfs_set_item_offset(right
->items
+ i
, ioff
+ rt_data_off
);
1103 btrfs_set_header_nritems(&l
->header
, mid
);
1105 wret
= insert_ptr(root
, path
, &right
->items
[0].key
,
1106 right_buffer
->blocknr
, path
->slots
[1] + 1, 1);
1109 BUG_ON(list_empty(&right_buffer
->dirty
));
1110 BUG_ON(list_empty(&l_buf
->dirty
));
1111 BUG_ON(path
->slots
[0] != slot
);
1113 btrfs_block_release(root
, path
->nodes
[0]);
1114 path
->nodes
[0] = right_buffer
;
1115 path
->slots
[0] -= mid
;
1116 path
->slots
[1] += 1;
1118 btrfs_block_release(root
, right_buffer
);
1119 BUG_ON(path
->slots
[0] < 0);
1124 * Given a key and some data, insert an item into the tree.
1125 * This does all the path init required, making room in the tree if needed.
1127 int btrfs_insert_item(struct btrfs_root
*root
, struct btrfs_key
*cpu_key
,
1128 void *data
, int data_size
)
1133 struct btrfs_leaf
*leaf
;
1134 struct btrfs_buffer
*leaf_buf
;
1136 unsigned int data_end
;
1137 struct btrfs_path path
;
1138 struct btrfs_disk_key disk_key
;
1140 btrfs_cpu_key_to_disk(&disk_key
, cpu_key
);
1142 /* create a root if there isn't one */
1145 btrfs_init_path(&path
);
1146 ret
= btrfs_search_slot(root
, cpu_key
, &path
, data_size
, 1);
1148 btrfs_release_path(root
, &path
);
1154 slot_orig
= path
.slots
[0];
1155 leaf_buf
= path
.nodes
[0];
1156 leaf
= &leaf_buf
->leaf
;
1158 nritems
= btrfs_header_nritems(&leaf
->header
);
1159 data_end
= leaf_data_end(leaf
);
1161 if (btrfs_leaf_free_space(leaf
) <
1162 sizeof(struct btrfs_item
) + data_size
)
1165 slot
= path
.slots
[0];
1167 if (slot
!= nritems
) {
1169 unsigned int old_data
= btrfs_item_end(leaf
->items
+ slot
);
1172 * item0..itemN ... dataN.offset..dataN.size .. data0.size
1174 /* first correct the data pointers */
1175 for (i
= slot
; i
< nritems
; i
++) {
1176 u16 ioff
= btrfs_item_offset(leaf
->items
+ i
);
1177 btrfs_set_item_offset(leaf
->items
+ i
,
1181 /* shift the items */
1182 memmove(leaf
->items
+ slot
+ 1, leaf
->items
+ slot
,
1183 (nritems
- slot
) * sizeof(struct btrfs_item
));
1185 /* shift the data */
1186 memmove(leaf
->data
+ data_end
- data_size
, leaf
->data
+
1187 data_end
, old_data
- data_end
);
1188 data_end
= old_data
;
1190 /* copy the new data in */
1191 memcpy(&leaf
->items
[slot
].key
, &disk_key
,
1192 sizeof(struct btrfs_disk_key
));
1193 btrfs_set_item_offset(leaf
->items
+ slot
, data_end
- data_size
);
1194 btrfs_set_item_size(leaf
->items
+ slot
, data_size
);
1195 memcpy(leaf
->data
+ data_end
- data_size
, data
, data_size
);
1196 btrfs_set_header_nritems(&leaf
->header
, nritems
+ 1);
1200 ret
= fixup_low_keys(root
, &path
, &disk_key
, 1);
1202 BUG_ON(list_empty(&leaf_buf
->dirty
));
1203 if (btrfs_leaf_free_space(leaf
) < 0)
1205 check_leaf(&path
, 0);
1207 btrfs_release_path(root
, &path
);
1212 * delete the pointer from a given node.
1214 * If the delete empties a node, the node is removed from the tree,
1215 * continuing all the way the root if required. The root is converted into
1216 * a leaf if all the nodes are emptied.
1218 static int del_ptr(struct btrfs_root
*root
, struct btrfs_path
*path
, int level
,
1221 struct btrfs_node
*node
;
1222 struct btrfs_buffer
*parent
= path
->nodes
[level
];
1227 node
= &parent
->node
;
1228 nritems
= btrfs_header_nritems(&node
->header
);
1229 if (slot
!= nritems
-1) {
1230 memmove(node
->keys
+ slot
, node
->keys
+ slot
+ 1,
1231 sizeof(struct btrfs_disk_key
) * (nritems
- slot
- 1));
1232 memmove(node
->blockptrs
+ slot
,
1233 node
->blockptrs
+ slot
+ 1,
1234 sizeof(u64
) * (nritems
- slot
- 1));
1237 btrfs_set_header_nritems(&node
->header
, nritems
);
1238 if (nritems
== 0 && parent
== root
->node
) {
1239 BUG_ON(btrfs_header_level(&root
->node
->node
.header
) != 1);
1240 /* just turn the root into a leaf and break */
1241 btrfs_set_header_level(&root
->node
->node
.header
, 0);
1242 } else if (slot
== 0) {
1243 wret
= fixup_low_keys(root
, path
, node
->keys
, level
+ 1);
1247 BUG_ON(list_empty(&parent
->dirty
));
1252 * delete the item at the leaf level in path. If that empties
1253 * the leaf, remove it from the tree
1255 int btrfs_del_item(struct btrfs_root
*root
, struct btrfs_path
*path
)
1258 struct btrfs_leaf
*leaf
;
1259 struct btrfs_buffer
*leaf_buf
;
1266 leaf_buf
= path
->nodes
[0];
1267 leaf
= &leaf_buf
->leaf
;
1268 slot
= path
->slots
[0];
1269 doff
= btrfs_item_offset(leaf
->items
+ slot
);
1270 dsize
= btrfs_item_size(leaf
->items
+ slot
);
1271 nritems
= btrfs_header_nritems(&leaf
->header
);
1273 if (slot
!= nritems
- 1) {
1275 int data_end
= leaf_data_end(leaf
);
1276 memmove(leaf
->data
+ data_end
+ dsize
,
1277 leaf
->data
+ data_end
,
1279 for (i
= slot
+ 1; i
< nritems
; i
++) {
1280 u16 ioff
= btrfs_item_offset(leaf
->items
+ i
);
1281 btrfs_set_item_offset(leaf
->items
+ i
, ioff
+ dsize
);
1283 memmove(leaf
->items
+ slot
, leaf
->items
+ slot
+ 1,
1284 sizeof(struct btrfs_item
) *
1285 (nritems
- slot
- 1));
1287 btrfs_set_header_nritems(&leaf
->header
, nritems
- 1);
1289 /* delete the leaf if we've emptied it */
1291 if (leaf_buf
== root
->node
) {
1292 btrfs_set_header_level(&leaf
->header
, 0);
1293 BUG_ON(list_empty(&leaf_buf
->dirty
));
1295 clean_tree_block(root
, leaf_buf
);
1296 wret
= del_ptr(root
, path
, 1, path
->slots
[1]);
1299 wret
= btrfs_free_extent(root
, leaf_buf
->blocknr
, 1);
1304 int used
= leaf_space_used(leaf
, 0, nritems
);
1306 wret
= fixup_low_keys(root
, path
,
1307 &leaf
->items
[0].key
, 1);
1311 BUG_ON(list_empty(&leaf_buf
->dirty
));
1313 /* delete the leaf if it is mostly empty */
1314 if (used
< LEAF_DATA_SIZE
/ 3) {
1315 /* push_leaf_left fixes the path.
1316 * make sure the path still points to our leaf
1317 * for possible call to del_ptr below
1319 slot
= path
->slots
[1];
1321 wret
= push_leaf_left(root
, path
, 1);
1324 if (path
->nodes
[0] == leaf_buf
&&
1325 btrfs_header_nritems(&leaf
->header
)) {
1326 wret
= push_leaf_right(root
, path
, 1);
1330 if (btrfs_header_nritems(&leaf
->header
) == 0) {
1331 u64 blocknr
= leaf_buf
->blocknr
;
1332 clean_tree_block(root
, leaf_buf
);
1333 wret
= del_ptr(root
, path
, 1, slot
);
1336 btrfs_block_release(root
, leaf_buf
);
1337 wret
= btrfs_free_extent(root
, blocknr
, 1);
1341 btrfs_block_release(root
, leaf_buf
);
1349 * walk up the tree as far as required to find the next leaf.
1350 * returns 0 if it found something or 1 if there are no greater leaves.
1351 * returns < 0 on io errors.
1353 int btrfs_next_leaf(struct btrfs_root
*root
, struct btrfs_path
*path
)
1358 struct btrfs_buffer
*c
;
1359 struct btrfs_buffer
*next
= NULL
;
1361 while(level
< BTRFS_MAX_LEVEL
) {
1362 if (!path
->nodes
[level
])
1364 slot
= path
->slots
[level
] + 1;
1365 c
= path
->nodes
[level
];
1366 if (slot
>= btrfs_header_nritems(&c
->node
.header
)) {
1370 blocknr
= btrfs_node_blockptr(&c
->node
, slot
);
1372 btrfs_block_release(root
, next
);
1373 next
= read_tree_block(root
, blocknr
);
1376 path
->slots
[level
] = slot
;
1379 c
= path
->nodes
[level
];
1380 btrfs_block_release(root
, c
);
1381 path
->nodes
[level
] = next
;
1382 path
->slots
[level
] = 0;
1385 next
= read_tree_block(root
,
1386 btrfs_node_blockptr(&next
->node
, 0));
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