3 #include "kerncompat.h"
4 #include "radix-tree.h"
7 #include "print-tree.h"
9 static int split_node(struct ctree_root
*root
, struct ctree_path
*path
,
11 static int split_leaf(struct ctree_root
*root
, struct ctree_path
*path
,
13 static int push_node_left(struct ctree_root
*root
, struct ctree_path
*path
,
15 static int push_node_right(struct ctree_root
*root
,
16 struct ctree_path
*path
, int level
);
17 static int del_ptr(struct ctree_root
*root
, struct ctree_path
*path
, int level
);
19 inline void init_path(struct ctree_path
*p
)
21 memset(p
, 0, sizeof(*p
));
24 void release_path(struct ctree_root
*root
, struct ctree_path
*p
)
27 for (i
= 0; i
< MAX_LEVEL
; i
++) {
30 tree_block_release(root
, p
->nodes
[i
]);
32 memset(p
, 0, sizeof(*p
));
36 * The leaf data grows from end-to-front in the node.
37 * this returns the address of the start of the last item,
38 * which is the stop of the leaf data stack
40 static inline unsigned int leaf_data_end(struct leaf
*leaf
)
42 unsigned int nr
= leaf
->header
.nritems
;
44 return sizeof(leaf
->data
);
45 return leaf
->items
[nr
-1].offset
;
49 * The space between the end of the leaf items and
50 * the start of the leaf data. IOW, how much room
51 * the leaf has left for both items and data
53 int leaf_free_space(struct leaf
*leaf
)
55 int data_end
= leaf_data_end(leaf
);
56 int nritems
= leaf
->header
.nritems
;
57 char *items_end
= (char *)(leaf
->items
+ nritems
+ 1);
58 return (char *)(leaf
->data
+ data_end
) - (char *)items_end
;
62 * compare two keys in a memcmp fashion
64 int comp_keys(struct key
*k1
, struct key
*k2
)
66 if (k1
->objectid
> k2
->objectid
)
68 if (k1
->objectid
< k2
->objectid
)
70 if (k1
->flags
> k2
->flags
)
72 if (k1
->flags
< k2
->flags
)
74 if (k1
->offset
> k2
->offset
)
76 if (k1
->offset
< k2
->offset
)
81 int check_node(struct ctree_path
*path
, int level
)
84 struct node
*parent
= NULL
;
85 struct node
*node
= &path
->nodes
[level
]->node
;
88 if (path
->nodes
[level
+ 1])
89 parent
= &path
->nodes
[level
+ 1]->node
;
90 parent_slot
= path
->slots
[level
+ 1];
91 if (parent
&& node
->header
.nritems
> 0) {
92 struct key
*parent_key
;
93 parent_key
= &parent
->keys
[parent_slot
];
94 BUG_ON(memcmp(parent_key
, node
->keys
, sizeof(struct key
)));
95 BUG_ON(parent
->blockptrs
[parent_slot
] != node
->header
.blocknr
);
97 BUG_ON(node
->header
.nritems
> NODEPTRS_PER_BLOCK
);
98 for (i
= 0; i
< node
->header
.nritems
- 2; i
++) {
99 BUG_ON(comp_keys(&node
->keys
[i
], &node
->keys
[i
+1]) >= 0);
104 int check_leaf(struct ctree_path
*path
, int level
)
107 struct leaf
*leaf
= &path
->nodes
[level
]->leaf
;
108 struct node
*parent
= NULL
;
111 if (path
->nodes
[level
+ 1])
112 parent
= &path
->nodes
[level
+ 1]->node
;
113 parent_slot
= path
->slots
[level
+ 1];
114 if (parent
&& leaf
->header
.nritems
> 0) {
115 struct key
*parent_key
;
116 parent_key
= &parent
->keys
[parent_slot
];
117 BUG_ON(memcmp(parent_key
, &leaf
->items
[0].key
,
118 sizeof(struct key
)));
119 BUG_ON(parent
->blockptrs
[parent_slot
] != leaf
->header
.blocknr
);
121 for (i
= 0; i
< leaf
->header
.nritems
- 2; i
++) {
122 BUG_ON(comp_keys(&leaf
->items
[i
].key
,
123 &leaf
->items
[i
+1].key
) >= 0);
124 BUG_ON(leaf
->items
[i
].offset
!= leaf
->items
[i
+ 1].offset
+
125 leaf
->items
[i
+ 1].size
);
127 BUG_ON(leaf
->items
[i
].offset
+ leaf
->items
[i
].size
!=
131 BUG_ON(leaf_free_space(leaf
) < 0);
135 int check_block(struct ctree_path
*path
, int level
)
138 return check_leaf(path
, level
);
139 return check_node(path
, level
);
143 * search for key in the array p. items p are item_size apart
144 * and there are 'max' items in p
145 * the slot in the array is returned via slot, and it points to
146 * the place where you would insert key if it is not found in
149 * slot may point to max if the key is bigger than all of the keys
151 int generic_bin_search(char *p
, int item_size
, struct key
*key
,
161 mid
= (low
+ high
) / 2;
162 tmp
= (struct key
*)(p
+ mid
* item_size
);
163 ret
= comp_keys(tmp
, key
);
179 * simple bin_search frontend that does the right thing for
182 int bin_search(struct node
*c
, struct key
*key
, int *slot
)
184 if (is_leaf(c
->header
.flags
)) {
185 struct leaf
*l
= (struct leaf
*)c
;
186 return generic_bin_search((void *)l
->items
, sizeof(struct item
),
187 key
, c
->header
.nritems
, slot
);
189 return generic_bin_search((void *)c
->keys
, sizeof(struct key
),
190 key
, c
->header
.nritems
, slot
);
196 * look for key in the tree. path is filled in with nodes along the way
197 * if key is found, we return zero and you can find the item in the leaf
198 * level of the path (level 0)
200 * If the key isn't found, the path points to the slot where it should
201 * be inserted, and 1 is returned. If there are other errors during the
202 * search a negative error number is returned.
204 * if ins_len > 0, nodes and leaves will be split as we walk down the
205 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
208 int search_slot(struct ctree_root
*root
, struct key
*key
,
209 struct ctree_path
*p
, int ins_len
)
211 struct tree_buffer
*b
= root
->node
;
220 level
= node_level(c
->header
.flags
);
222 ret
= check_block(p
, level
);
225 ret
= bin_search(c
, key
, &slot
);
226 if (!is_leaf(c
->header
.flags
)) {
229 p
->slots
[level
] = slot
;
231 c
->header
.nritems
== NODEPTRS_PER_BLOCK
) {
232 int sret
= split_node(root
, p
, level
);
238 slot
= p
->slots
[level
];
240 b
= read_tree_block(root
, c
->blockptrs
[slot
]);
243 struct leaf
*l
= (struct leaf
*)c
;
244 p
->slots
[level
] = slot
;
245 if (ins_len
> 0 && leaf_free_space(l
) <
246 sizeof(struct item
) + ins_len
) {
247 int sret
= split_leaf(root
, p
, ins_len
);
259 * adjust the pointers going up the tree, starting at level
260 * making sure the right key of each node is points to 'key'.
261 * This is used after shifting pointers to the left, so it stops
262 * fixing up pointers when a given leaf/node is not in slot 0 of the
265 * If this fails to write a tree block, it returns -1, but continues
266 * fixing up the blocks in ram so the tree is consistent.
268 static int fixup_low_keys(struct ctree_root
*root
,
269 struct ctree_path
*path
, struct key
*key
,
275 for (i
= level
; i
< MAX_LEVEL
; i
++) {
277 int tslot
= path
->slots
[i
];
280 t
= &path
->nodes
[i
]->node
;
281 memcpy(t
->keys
+ tslot
, key
, sizeof(*key
));
282 wret
= write_tree_block(root
, path
->nodes
[i
]);
292 * try to push data from one node into the next node left in the
293 * tree. The src node is found at specified level in the path.
294 * If some bytes were pushed, return 0, otherwise return 1.
296 * Lower nodes/leaves in the path are not touched, higher nodes may
297 * be modified to reflect the push.
299 * The path is altered to reflect the push.
301 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
302 * error, and > 0 if there was no room in the left hand block.
304 static int push_node_left(struct ctree_root
*root
, struct ctree_path
*path
,
313 struct tree_buffer
*t
;
314 struct tree_buffer
*right_buf
;
318 if (level
== MAX_LEVEL
- 1 || path
->nodes
[level
+ 1] == 0)
320 slot
= path
->slots
[level
+ 1];
324 t
= read_tree_block(root
,
325 path
->nodes
[level
+ 1]->node
.blockptrs
[slot
- 1]);
327 right_buf
= path
->nodes
[level
];
328 right
= &right_buf
->node
;
329 left_nritems
= left
->header
.nritems
;
330 right_nritems
= right
->header
.nritems
;
331 push_items
= NODEPTRS_PER_BLOCK
- (left_nritems
+ 1);
332 if (push_items
<= 0) {
333 tree_block_release(root
, t
);
337 if (right_nritems
< push_items
)
338 push_items
= right_nritems
;
339 memcpy(left
->keys
+ left_nritems
, right
->keys
,
340 push_items
* sizeof(struct key
));
341 memcpy(left
->blockptrs
+ left_nritems
, right
->blockptrs
,
342 push_items
* sizeof(u64
));
343 memmove(right
->keys
, right
->keys
+ push_items
,
344 (right_nritems
- push_items
) * sizeof(struct key
));
345 memmove(right
->blockptrs
, right
->blockptrs
+ push_items
,
346 (right_nritems
- push_items
) * sizeof(u64
));
347 right
->header
.nritems
-= push_items
;
348 left
->header
.nritems
+= push_items
;
350 /* adjust the pointers going up the tree */
351 wret
= fixup_low_keys(root
, path
, right
->keys
, level
+ 1);
355 wret
= write_tree_block(root
, t
);
359 wret
= write_tree_block(root
, right_buf
);
363 /* then fixup the leaf pointer in the path */
364 if (path
->slots
[level
] < push_items
) {
365 path
->slots
[level
] += left_nritems
;
366 tree_block_release(root
, path
->nodes
[level
]);
367 path
->nodes
[level
] = t
;
368 path
->slots
[level
+ 1] -= 1;
370 path
->slots
[level
] -= push_items
;
371 tree_block_release(root
, t
);
377 * try to push data from one node into the next node right in the
378 * tree. The src node is found at specified level in the path.
379 * If some bytes were pushed, return 0, otherwise return 1.
381 * Lower nodes/leaves in the path are not touched, higher nodes may
382 * be modified to reflect the push.
384 * The path is altered to reflect the push.
386 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
387 * error, and > 0 if there was no room in the right hand block.
389 static int push_node_right(struct ctree_root
*root
, struct ctree_path
*path
,
393 struct tree_buffer
*t
;
394 struct tree_buffer
*src_buffer
;
401 /* can't push from the root */
402 if (level
== MAX_LEVEL
- 1 || path
->nodes
[level
+ 1] == 0)
405 /* only try to push inside the node higher up */
406 slot
= path
->slots
[level
+ 1];
407 if (slot
== NODEPTRS_PER_BLOCK
- 1)
410 if (slot
>= path
->nodes
[level
+ 1]->node
.header
.nritems
-1)
413 t
= read_tree_block(root
,
414 path
->nodes
[level
+ 1]->node
.blockptrs
[slot
+ 1]);
416 src_buffer
= path
->nodes
[level
];
417 src
= &src_buffer
->node
;
418 dst_nritems
= dst
->header
.nritems
;
419 src_nritems
= src
->header
.nritems
;
420 push_items
= NODEPTRS_PER_BLOCK
- (dst_nritems
+ 1);
421 if (push_items
<= 0) {
422 tree_block_release(root
, t
);
426 if (src_nritems
< push_items
)
427 push_items
= src_nritems
;
428 memmove(dst
->keys
+ push_items
, dst
->keys
,
429 dst_nritems
* sizeof(struct key
));
430 memcpy(dst
->keys
, src
->keys
+ src_nritems
- push_items
,
431 push_items
* sizeof(struct key
));
433 memmove(dst
->blockptrs
+ push_items
, dst
->blockptrs
,
434 dst_nritems
* sizeof(u64
));
435 memcpy(dst
->blockptrs
, src
->blockptrs
+ src_nritems
- push_items
,
436 push_items
* sizeof(u64
));
438 src
->header
.nritems
-= push_items
;
439 dst
->header
.nritems
+= push_items
;
441 /* adjust the pointers going up the tree */
442 memcpy(path
->nodes
[level
+ 1]->node
.keys
+ path
->slots
[level
+ 1] + 1,
443 dst
->keys
, sizeof(struct key
));
445 write_tree_block(root
, path
->nodes
[level
+ 1]);
446 write_tree_block(root
, t
);
447 write_tree_block(root
, src_buffer
);
449 /* then fixup the pointers in the path */
450 if (path
->slots
[level
] >= src
->header
.nritems
) {
451 path
->slots
[level
] -= src
->header
.nritems
;
452 tree_block_release(root
, path
->nodes
[level
]);
453 path
->nodes
[level
] = t
;
454 path
->slots
[level
+ 1] += 1;
456 tree_block_release(root
, t
);
462 * helper function to insert a new root level in the tree.
463 * A new node is allocated, and a single item is inserted to
464 * point to the existing root
466 * returns zero on success or < 0 on failure.
468 static int insert_new_root(struct ctree_root
*root
,
469 struct ctree_path
*path
, int level
)
471 struct tree_buffer
*t
;
474 struct key
*lower_key
;
476 BUG_ON(path
->nodes
[level
]);
477 BUG_ON(path
->nodes
[level
-1] != root
->node
);
479 t
= alloc_free_block(root
);
481 memset(c
, 0, sizeof(c
));
482 c
->header
.nritems
= 1;
483 c
->header
.flags
= node_level(level
);
484 c
->header
.blocknr
= t
->blocknr
;
485 c
->header
.parentid
= root
->node
->node
.header
.parentid
;
486 lower
= &path
->nodes
[level
-1]->node
;
487 if (is_leaf(lower
->header
.flags
))
488 lower_key
= &((struct leaf
*)lower
)->items
[0].key
;
490 lower_key
= lower
->keys
;
491 memcpy(c
->keys
, lower_key
, sizeof(struct key
));
492 c
->blockptrs
[0] = path
->nodes
[level
-1]->blocknr
;
493 /* the super has an extra ref to root->node */
494 tree_block_release(root
, root
->node
);
497 write_tree_block(root
, t
);
498 path
->nodes
[level
] = t
;
499 path
->slots
[level
] = 0;
504 * worker function to insert a single pointer in a node.
505 * the node should have enough room for the pointer already
507 * slot and level indicate where you want the key to go, and
508 * blocknr is the block the key points to.
510 * returns zero on success and < 0 on any error
512 static int insert_ptr(struct ctree_root
*root
,
513 struct ctree_path
*path
, struct key
*key
,
514 u64 blocknr
, int slot
, int level
)
519 BUG_ON(!path
->nodes
[level
]);
520 lower
= &path
->nodes
[level
]->node
;
521 nritems
= lower
->header
.nritems
;
524 if (nritems
== NODEPTRS_PER_BLOCK
)
526 if (slot
!= nritems
) {
527 memmove(lower
->keys
+ slot
+ 1, lower
->keys
+ slot
,
528 (nritems
- slot
) * sizeof(struct key
));
529 memmove(lower
->blockptrs
+ slot
+ 1, lower
->blockptrs
+ slot
,
530 (nritems
- slot
) * sizeof(u64
));
532 memcpy(lower
->keys
+ slot
, key
, sizeof(struct key
));
533 lower
->blockptrs
[slot
] = blocknr
;
534 lower
->header
.nritems
++;
535 if (lower
->keys
[1].objectid
== 0)
537 write_tree_block(root
, path
->nodes
[level
]);
542 * split the node at the specified level in path in two.
543 * The path is corrected to point to the appropriate node after the split
545 * Before splitting this tries to make some room in the node by pushing
546 * left and right, if either one works, it returns right away.
548 * returns 0 on success and < 0 on failure
550 static int split_node(struct ctree_root
*root
, struct ctree_path
*path
,
553 struct tree_buffer
*t
;
555 struct tree_buffer
*split_buffer
;
561 ret
= push_node_left(root
, path
, level
);
566 ret
= push_node_right(root
, path
, level
);
571 t
= path
->nodes
[level
];
573 if (t
== root
->node
) {
574 /* trying to split the root, lets make a new one */
575 ret
= insert_new_root(root
, path
, level
+ 1);
579 split_buffer
= alloc_free_block(root
);
580 split
= &split_buffer
->node
;
581 split
->header
.flags
= c
->header
.flags
;
582 split
->header
.blocknr
= split_buffer
->blocknr
;
583 split
->header
.parentid
= root
->node
->node
.header
.parentid
;
584 mid
= (c
->header
.nritems
+ 1) / 2;
585 memcpy(split
->keys
, c
->keys
+ mid
,
586 (c
->header
.nritems
- mid
) * sizeof(struct key
));
587 memcpy(split
->blockptrs
, c
->blockptrs
+ mid
,
588 (c
->header
.nritems
- mid
) * sizeof(u64
));
589 split
->header
.nritems
= c
->header
.nritems
- mid
;
590 c
->header
.nritems
= mid
;
593 wret
= write_tree_block(root
, t
);
596 wret
= write_tree_block(root
, split_buffer
);
599 wret
= insert_ptr(root
, path
, split
->keys
, split_buffer
->blocknr
,
600 path
->slots
[level
+ 1] + 1, level
+ 1);
604 if (path
->slots
[level
] >= mid
) {
605 path
->slots
[level
] -= mid
;
606 tree_block_release(root
, t
);
607 path
->nodes
[level
] = split_buffer
;
608 path
->slots
[level
+ 1] += 1;
610 tree_block_release(root
, split_buffer
);
616 * how many bytes are required to store the items in a leaf. start
617 * and nr indicate which items in the leaf to check. This totals up the
618 * space used both by the item structs and the item data
620 static int leaf_space_used(struct leaf
*l
, int start
, int nr
)
623 int end
= start
+ nr
- 1;
627 data_len
= l
->items
[start
].offset
+ l
->items
[start
].size
;
628 data_len
= data_len
- l
->items
[end
].offset
;
629 data_len
+= sizeof(struct item
) * nr
;
634 * push some data in the path leaf to the right, trying to free up at
635 * least data_size bytes. returns zero if the push worked, nonzero otherwise
637 * returns 1 if the push failed because the other node didn't have enough
638 * room, 0 if everything worked out and < 0 if there were major errors.
640 static int push_leaf_right(struct ctree_root
*root
, struct ctree_path
*path
,
643 struct tree_buffer
*left_buf
= path
->nodes
[0];
644 struct leaf
*left
= &left_buf
->leaf
;
646 struct tree_buffer
*right_buf
;
647 struct tree_buffer
*upper
;
655 slot
= path
->slots
[1];
656 if (!path
->nodes
[1]) {
659 upper
= path
->nodes
[1];
660 if (slot
>= upper
->node
.header
.nritems
- 1) {
663 right_buf
= read_tree_block(root
, upper
->node
.blockptrs
[slot
+ 1]);
664 right
= &right_buf
->leaf
;
665 free_space
= leaf_free_space(right
);
666 if (free_space
< data_size
+ sizeof(struct item
)) {
667 tree_block_release(root
, right_buf
);
670 for (i
= left
->header
.nritems
- 1; i
>= 0; i
--) {
671 item
= left
->items
+ i
;
672 if (path
->slots
[0] == i
)
673 push_space
+= data_size
+ sizeof(*item
);
674 if (item
->size
+ sizeof(*item
) + push_space
> free_space
)
677 push_space
+= item
->size
+ sizeof(*item
);
679 if (push_items
== 0) {
680 tree_block_release(root
, right_buf
);
683 /* push left to right */
684 push_space
= left
->items
[left
->header
.nritems
- push_items
].offset
+
685 left
->items
[left
->header
.nritems
- push_items
].size
;
686 push_space
-= leaf_data_end(left
);
687 /* make room in the right data area */
688 memmove(right
->data
+ leaf_data_end(right
) - push_space
,
689 right
->data
+ leaf_data_end(right
),
690 LEAF_DATA_SIZE
- leaf_data_end(right
));
691 /* copy from the left data area */
692 memcpy(right
->data
+ LEAF_DATA_SIZE
- push_space
,
693 left
->data
+ leaf_data_end(left
),
695 memmove(right
->items
+ push_items
, right
->items
,
696 right
->header
.nritems
* sizeof(struct item
));
697 /* copy the items from left to right */
698 memcpy(right
->items
, left
->items
+ left
->header
.nritems
- push_items
,
699 push_items
* sizeof(struct item
));
701 /* update the item pointers */
702 right
->header
.nritems
+= push_items
;
703 push_space
= LEAF_DATA_SIZE
;
704 for (i
= 0; i
< right
->header
.nritems
; i
++) {
705 right
->items
[i
].offset
= push_space
- right
->items
[i
].size
;
706 push_space
= right
->items
[i
].offset
;
708 left
->header
.nritems
-= push_items
;
710 write_tree_block(root
, left_buf
);
711 write_tree_block(root
, right_buf
);
712 memcpy(upper
->node
.keys
+ slot
+ 1,
713 &right
->items
[0].key
, sizeof(struct key
));
714 write_tree_block(root
, upper
);
715 /* then fixup the leaf pointer in the path */
716 if (path
->slots
[0] >= left
->header
.nritems
) {
717 path
->slots
[0] -= left
->header
.nritems
;
718 tree_block_release(root
, path
->nodes
[0]);
719 path
->nodes
[0] = right_buf
;
722 tree_block_release(root
, right_buf
);
727 * push some data in the path leaf to the left, trying to free up at
728 * least data_size bytes. returns zero if the push worked, nonzero otherwise
730 static int push_leaf_left(struct ctree_root
*root
, struct ctree_path
*path
,
733 struct tree_buffer
*right_buf
= path
->nodes
[0];
734 struct leaf
*right
= &right_buf
->leaf
;
735 struct tree_buffer
*t
;
743 int old_left_nritems
;
747 slot
= path
->slots
[1];
751 if (!path
->nodes
[1]) {
754 t
= read_tree_block(root
, path
->nodes
[1]->node
.blockptrs
[slot
- 1]);
756 free_space
= leaf_free_space(left
);
757 if (free_space
< data_size
+ sizeof(struct item
)) {
758 tree_block_release(root
, t
);
761 for (i
= 0; i
< right
->header
.nritems
; i
++) {
762 item
= right
->items
+ i
;
763 if (path
->slots
[0] == i
)
764 push_space
+= data_size
+ sizeof(*item
);
765 if (item
->size
+ sizeof(*item
) + push_space
> free_space
)
768 push_space
+= item
->size
+ sizeof(*item
);
770 if (push_items
== 0) {
771 tree_block_release(root
, t
);
774 /* push data from right to left */
775 memcpy(left
->items
+ left
->header
.nritems
,
776 right
->items
, push_items
* sizeof(struct item
));
777 push_space
= LEAF_DATA_SIZE
- right
->items
[push_items
-1].offset
;
778 memcpy(left
->data
+ leaf_data_end(left
) - push_space
,
779 right
->data
+ right
->items
[push_items
- 1].offset
,
781 old_left_nritems
= left
->header
.nritems
;
782 BUG_ON(old_left_nritems
< 0);
784 for(i
= old_left_nritems
; i
< old_left_nritems
+ push_items
; i
++) {
785 left
->items
[i
].offset
-= LEAF_DATA_SIZE
-
786 left
->items
[old_left_nritems
-1].offset
;
788 left
->header
.nritems
+= push_items
;
790 /* fixup right node */
791 push_space
= right
->items
[push_items
-1].offset
- leaf_data_end(right
);
792 memmove(right
->data
+ LEAF_DATA_SIZE
- push_space
, right
->data
+
793 leaf_data_end(right
), push_space
);
794 memmove(right
->items
, right
->items
+ push_items
,
795 (right
->header
.nritems
- push_items
) * sizeof(struct item
));
796 right
->header
.nritems
-= push_items
;
797 push_space
= LEAF_DATA_SIZE
;
799 for (i
= 0; i
< right
->header
.nritems
; i
++) {
800 right
->items
[i
].offset
= push_space
- right
->items
[i
].size
;
801 push_space
= right
->items
[i
].offset
;
804 wret
= write_tree_block(root
, t
);
807 wret
= write_tree_block(root
, right_buf
);
811 wret
= fixup_low_keys(root
, path
, &right
->items
[0].key
, 1);
815 /* then fixup the leaf pointer in the path */
816 if (path
->slots
[0] < push_items
) {
817 path
->slots
[0] += old_left_nritems
;
818 tree_block_release(root
, path
->nodes
[0]);
822 tree_block_release(root
, t
);
823 path
->slots
[0] -= push_items
;
825 BUG_ON(path
->slots
[0] < 0);
830 * split the path's leaf in two, making sure there is at least data_size
831 * available for the resulting leaf level of the path.
833 * returns 0 if all went well and < 0 on failure.
835 static int split_leaf(struct ctree_root
*root
, struct ctree_path
*path
,
838 struct tree_buffer
*l_buf
;
844 struct tree_buffer
*right_buffer
;
845 int space_needed
= data_size
+ sizeof(struct item
);
852 wret
= push_leaf_left(root
, path
, data_size
);
856 wret
= push_leaf_right(root
, path
, data_size
);
860 l_buf
= path
->nodes
[0];
863 /* did the pushes work? */
864 if (leaf_free_space(l
) >= sizeof(struct item
) + data_size
)
867 if (!path
->nodes
[1]) {
868 ret
= insert_new_root(root
, path
, 1);
872 slot
= path
->slots
[0];
873 nritems
= l
->header
.nritems
;
874 mid
= (nritems
+ 1)/ 2;
876 right_buffer
= alloc_free_block(root
);
877 BUG_ON(!right_buffer
);
878 BUG_ON(mid
== nritems
);
879 right
= &right_buffer
->leaf
;
880 memset(right
, 0, sizeof(*right
));
882 /* FIXME, just alloc a new leaf here */
883 if (leaf_space_used(l
, mid
, nritems
- mid
) + space_needed
>
887 /* FIXME, just alloc a new leaf here */
888 if (leaf_space_used(l
, 0, mid
+ 1) + space_needed
>
892 right
->header
.nritems
= nritems
- mid
;
893 right
->header
.blocknr
= right_buffer
->blocknr
;
894 right
->header
.flags
= node_level(0);
895 right
->header
.parentid
= root
->node
->node
.header
.parentid
;
896 data_copy_size
= l
->items
[mid
].offset
+ l
->items
[mid
].size
-
898 memcpy(right
->items
, l
->items
+ mid
,
899 (nritems
- mid
) * sizeof(struct item
));
900 memcpy(right
->data
+ LEAF_DATA_SIZE
- data_copy_size
,
901 l
->data
+ leaf_data_end(l
), data_copy_size
);
902 rt_data_off
= LEAF_DATA_SIZE
-
903 (l
->items
[mid
].offset
+ l
->items
[mid
].size
);
905 for (i
= 0; i
< right
->header
.nritems
; i
++)
906 right
->items
[i
].offset
+= rt_data_off
;
908 l
->header
.nritems
= mid
;
910 wret
= insert_ptr(root
, path
, &right
->items
[0].key
,
911 right_buffer
->blocknr
, path
->slots
[1] + 1, 1);
914 wret
= write_tree_block(root
, right_buffer
);
917 wret
= write_tree_block(root
, l_buf
);
921 BUG_ON(path
->slots
[0] != slot
);
923 tree_block_release(root
, path
->nodes
[0]);
924 path
->nodes
[0] = right_buffer
;
925 path
->slots
[0] -= mid
;
928 tree_block_release(root
, right_buffer
);
929 BUG_ON(path
->slots
[0] < 0);
934 * Given a key and some data, insert an item into the tree.
935 * This does all the path init required, making room in the tree if needed.
937 int insert_item(struct ctree_root
*root
, struct key
*key
,
938 void *data
, int data_size
)
945 struct tree_buffer
*leaf_buf
;
946 unsigned int nritems
;
947 unsigned int data_end
;
948 struct ctree_path path
;
950 /* create a root if there isn't one */
954 ret
= search_slot(root
, key
, &path
, data_size
);
956 release_path(root
, &path
);
960 release_path(root
, &path
);
964 slot_orig
= path
.slots
[0];
965 leaf_buf
= path
.nodes
[0];
966 leaf
= &leaf_buf
->leaf
;
968 nritems
= leaf
->header
.nritems
;
969 data_end
= leaf_data_end(leaf
);
971 if (leaf_free_space(leaf
) < sizeof(struct item
) + data_size
)
974 slot
= path
.slots
[0];
976 if (slot
!= nritems
) {
978 unsigned int old_data
= leaf
->items
[slot
].offset
+
979 leaf
->items
[slot
].size
;
982 * item0..itemN ... dataN.offset..dataN.size .. data0.size
984 /* first correct the data pointers */
985 for (i
= slot
; i
< nritems
; i
++)
986 leaf
->items
[i
].offset
-= data_size
;
988 /* shift the items */
989 memmove(leaf
->items
+ slot
+ 1, leaf
->items
+ slot
,
990 (nritems
- slot
) * sizeof(struct item
));
993 memmove(leaf
->data
+ data_end
- data_size
, leaf
->data
+
994 data_end
, old_data
- data_end
);
997 /* copy the new data in */
998 memcpy(&leaf
->items
[slot
].key
, key
, sizeof(struct key
));
999 leaf
->items
[slot
].offset
= data_end
- data_size
;
1000 leaf
->items
[slot
].size
= data_size
;
1001 memcpy(leaf
->data
+ data_end
- data_size
, data
, data_size
);
1002 leaf
->header
.nritems
+= 1;
1006 ret
= fixup_low_keys(root
, &path
, key
, 1);
1008 wret
= write_tree_block(root
, leaf_buf
);
1012 if (leaf_free_space(leaf
) < 0)
1014 release_path(root
, &path
);
1019 * delete the pointer from a given node.
1021 * If the delete empties a node, the node is removed from the tree,
1022 * continuing all the way the root if required. The root is converted into
1023 * a leaf if all the nodes are emptied.
1025 static int del_ptr(struct ctree_root
*root
, struct ctree_path
*path
, int level
)
1028 struct tree_buffer
*t
;
1036 t
= path
->nodes
[level
];
1040 slot
= path
->slots
[level
];
1041 nritems
= node
->header
.nritems
;
1043 if (slot
!= nritems
-1) {
1044 memmove(node
->keys
+ slot
, node
->keys
+ slot
+ 1,
1045 sizeof(struct key
) * (nritems
- slot
- 1));
1046 memmove(node
->blockptrs
+ slot
,
1047 node
->blockptrs
+ slot
+ 1,
1048 sizeof(u64
) * (nritems
- slot
- 1));
1050 node
->header
.nritems
--;
1051 blocknr
= t
->blocknr
;
1052 write_tree_block(root
, t
);
1053 if (node
->header
.nritems
!= 0) {
1056 wret
= fixup_low_keys(root
, path
,
1062 tslot
= path
->slots
[level
+ 1];
1064 wret
= push_node_left(root
, path
, level
);
1069 if (node
->header
.nritems
!= 0) {
1070 wret
= push_node_right(root
, path
, level
);
1076 path
->slots
[level
+ 1] = tslot
;
1077 if (node
->header
.nritems
!= 0) {
1078 tree_block_release(root
, t
);
1081 tree_block_release(root
, t
);
1083 if (t
== root
->node
) {
1084 /* just turn the root into a leaf and break */
1085 root
->node
->node
.header
.flags
= node_level(0);
1086 write_tree_block(root
, t
);
1090 wret
= free_extent(root
, blocknr
, 1);
1093 if (!path
->nodes
[level
])
1100 * delete the item at the leaf level in path. If that empties
1101 * the leaf, remove it from the tree
1103 int del_item(struct ctree_root
*root
, struct ctree_path
*path
)
1107 struct tree_buffer
*leaf_buf
;
1113 leaf_buf
= path
->nodes
[0];
1114 leaf
= &leaf_buf
->leaf
;
1115 slot
= path
->slots
[0];
1116 doff
= leaf
->items
[slot
].offset
;
1117 dsize
= leaf
->items
[slot
].size
;
1119 if (slot
!= leaf
->header
.nritems
- 1) {
1121 int data_end
= leaf_data_end(leaf
);
1122 memmove(leaf
->data
+ data_end
+ dsize
,
1123 leaf
->data
+ data_end
,
1125 for (i
= slot
+ 1; i
< leaf
->header
.nritems
; i
++)
1126 leaf
->items
[i
].offset
+= dsize
;
1127 memmove(leaf
->items
+ slot
, leaf
->items
+ slot
+ 1,
1128 sizeof(struct item
) *
1129 (leaf
->header
.nritems
- slot
- 1));
1131 leaf
->header
.nritems
-= 1;
1132 /* delete the leaf if we've emptied it */
1133 if (leaf
->header
.nritems
== 0) {
1134 if (leaf_buf
== root
->node
) {
1135 leaf
->header
.flags
= node_level(0);
1136 write_tree_block(root
, leaf_buf
);
1138 wret
= del_ptr(root
, path
, 1);
1141 wret
= free_extent(root
, leaf_buf
->blocknr
, 1);
1146 int used
= leaf_space_used(leaf
, 0, leaf
->header
.nritems
);
1148 wret
= fixup_low_keys(root
, path
,
1149 &leaf
->items
[0].key
, 1);
1153 wret
= write_tree_block(root
, leaf_buf
);
1157 /* delete the leaf if it is mostly empty */
1158 if (used
< LEAF_DATA_SIZE
/ 3) {
1159 /* push_leaf_left fixes the path.
1160 * make sure the path still points to our leaf
1161 * for possible call to del_ptr below
1163 slot
= path
->slots
[1];
1165 wret
= push_leaf_left(root
, path
, 1);
1168 if (leaf
->header
.nritems
) {
1169 wret
= push_leaf_right(root
, path
, 1);
1173 if (leaf
->header
.nritems
== 0) {
1174 u64 blocknr
= leaf_buf
->blocknr
;
1175 path
->slots
[1] = slot
;
1176 wret
= del_ptr(root
, path
, 1);
1179 tree_block_release(root
, leaf_buf
);
1180 wret
= free_extent(root
, blocknr
, 1);
1184 tree_block_release(root
, leaf_buf
);
1192 * walk up the tree as far as required to find the next leaf.
1193 * returns 0 if it found something or 1 if there are no greater leaves.
1194 * returns < 0 on io errors.
1196 int next_leaf(struct ctree_root
*root
, struct ctree_path
*path
)
1201 struct tree_buffer
*c
;
1202 struct tree_buffer
*next
= NULL
;
1204 while(level
< MAX_LEVEL
) {
1205 if (!path
->nodes
[level
])
1207 slot
= path
->slots
[level
] + 1;
1208 c
= path
->nodes
[level
];
1209 if (slot
>= c
->node
.header
.nritems
) {
1213 blocknr
= c
->node
.blockptrs
[slot
];
1215 tree_block_release(root
, next
);
1216 next
= read_tree_block(root
, blocknr
);
1219 path
->slots
[level
] = slot
;
1222 c
= path
->nodes
[level
];
1223 tree_block_release(root
, c
);
1224 path
->nodes
[level
] = next
;
1225 path
->slots
[level
] = 0;
1228 next
= read_tree_block(root
, next
->node
.blockptrs
[0]);