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 free_extent(root, blocknr, 1);
1091 if (!path->nodes[level])
1098 * delete the item at the leaf level in path. If that empties
1099 * the leaf, remove it from the tree
1101 int del_item(struct ctree_root *root, struct ctree_path *path)
1105 struct tree_buffer *leaf_buf;
1111 leaf_buf = path->nodes[0];
1112 leaf = &leaf_buf->leaf;
1113 slot = path->slots[0];
1114 doff = leaf->items[slot].offset;
1115 dsize = leaf->items[slot].size;
1117 if (slot != leaf->header.nritems - 1) {
1119 int data_end = leaf_data_end(leaf);
1120 memmove(leaf->data + data_end + dsize,
1121 leaf->data + data_end,
1123 for (i = slot + 1; i < leaf->header.nritems; i++)
1124 leaf->items[i].offset += dsize;
1125 memmove(leaf->items + slot, leaf->items + slot + 1,
1126 sizeof(struct item) *
1127 (leaf->header.nritems - slot - 1));
1129 leaf->header.nritems -= 1;
1130 /* delete the leaf if we've emptied it */
1131 if (leaf->header.nritems == 0) {
1132 if (leaf_buf == root->node) {
1133 leaf->header.flags = node_level(0);
1134 write_tree_block(root, leaf_buf);
1136 wret = del_ptr(root, path, 1);
1139 free_extent(root, leaf_buf->blocknr, 1);
1142 int used = leaf_space_used(leaf, 0, leaf->header.nritems);
1144 wret = fixup_low_keys(root, path,
1145 &leaf->items[0].key, 1);
1149 wret = write_tree_block(root, leaf_buf);
1153 /* delete the leaf if it is mostly empty */
1154 if (used < LEAF_DATA_SIZE / 3) {
1155 /* push_leaf_left fixes the path.
1156 * make sure the path still points to our leaf
1157 * for possible call to del_ptr below
1159 slot = path->slots[1];
1161 wret = push_leaf_left(root, path, 1);
1164 if (leaf->header.nritems) {
1165 wret = push_leaf_right(root, path, 1);
1169 if (leaf->header.nritems == 0) {
1170 u64 blocknr = leaf_buf->blocknr;
1171 path->slots[1] = slot;
1172 wret = del_ptr(root, path, 1);
1175 tree_block_release(root, leaf_buf);
1176 free_extent(root, blocknr, 1);
1178 tree_block_release(root, leaf_buf);
1186 * walk up the tree as far as required to find the next leaf.
1187 * returns 0 if it found something or -1 if there are no greater leaves.
1189 int next_leaf(struct ctree_root *root, struct ctree_path *path)
1194 struct tree_buffer *c;
1195 struct tree_buffer *next = NULL;
1197 while(level < MAX_LEVEL) {
1198 if (!path->nodes[level])
1200 slot = path->slots[level] + 1;
1201 c = path->nodes[level];
1202 if (slot >= c->node.header.nritems) {
1206 blocknr = c->node.blockptrs[slot];
1208 tree_block_release(root, next);
1209 next = read_tree_block(root, blocknr);
1212 path->slots[level] = slot;
1215 c = path->nodes[level];
1216 tree_block_release(root, c);
1217 path->nodes[level] = next;
1218 path->slots[level] = 0;
1221 next = read_tree_block(root, next->node.blockptrs[0]);