3 #include "kerncompat.h"
4 #include "radix-tree.h"
7 #include "print-tree.h"
9 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
10 *root, struct btrfs_path *path, int level);
11 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
12 *root, struct btrfs_path *path, int data_size);
13 static int push_node_left(struct btrfs_trans_handle *trans, struct btrfs_root
14 *root, struct btrfs_buffer *dst, struct btrfs_buffer
16 static int balance_node_right(struct btrfs_trans_handle *trans, struct
17 btrfs_root *root, struct btrfs_buffer *dst_buf,
18 struct btrfs_buffer *src_buf);
19 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
20 struct btrfs_path *path, int level, int slot);
22 inline void btrfs_init_path(struct btrfs_path *p)
24 memset(p, 0, sizeof(*p));
27 void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
30 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
33 btrfs_block_release(root, p->nodes[i]);
35 memset(p, 0, sizeof(*p));
38 static int btrfs_cow_block(struct btrfs_trans_handle *trans, struct btrfs_root
39 *root, struct btrfs_buffer *buf, struct btrfs_buffer
40 *parent, int parent_slot, struct btrfs_buffer
43 struct btrfs_buffer *cow;
45 if (!list_empty(&buf->dirty)) {
49 cow = btrfs_alloc_free_block(trans, root);
50 memcpy(&cow->node, &buf->node, root->blocksize);
51 btrfs_set_header_blocknr(&cow->node.header, cow->blocknr);
52 btrfs_set_header_owner(&cow->node.header, root->root_key.objectid);
54 btrfs_inc_ref(trans, root, buf);
55 if (buf == root->node) {
58 if (buf != root->commit_root)
59 btrfs_free_extent(trans, root, buf->blocknr, 1, 1);
60 btrfs_block_release(root, buf);
62 btrfs_set_node_blockptr(&parent->node, parent_slot,
64 BUG_ON(list_empty(&parent->dirty));
65 btrfs_free_extent(trans, root, buf->blocknr, 1, 1);
67 btrfs_block_release(root, buf);
72 * The leaf data grows from end-to-front in the node.
73 * this returns the address of the start of the last item,
74 * which is the stop of the leaf data stack
76 static inline unsigned int leaf_data_end(struct btrfs_root *root,
77 struct btrfs_leaf *leaf)
79 u32 nr = btrfs_header_nritems(&leaf->header);
81 return BTRFS_LEAF_DATA_SIZE(root);
82 return btrfs_item_offset(leaf->items + nr - 1);
86 * how many bytes are required to store the items in a leaf. start
87 * and nr indicate which items in the leaf to check. This totals up the
88 * space used both by the item structs and the item data
90 static int leaf_space_used(struct btrfs_leaf *l, int start, int nr)
93 int nritems = btrfs_header_nritems(&l->header);
96 if (nritems < start + nr)
103 data_len = btrfs_item_end(l->items + start);
104 data_len = data_len - btrfs_item_offset(l->items + end);
105 data_len += sizeof(struct btrfs_item) * nr;
110 * The space between the end of the leaf items and
111 * the start of the leaf data. IOW, how much room
112 * the leaf has left for both items and data
114 int btrfs_leaf_free_space(struct btrfs_root *root, struct btrfs_leaf *leaf)
116 int nritems = btrfs_header_nritems(&leaf->header);
117 return BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
121 * compare two keys in a memcmp fashion
123 int btrfs_comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
127 btrfs_disk_key_to_cpu(&k1, disk);
129 if (k1.objectid > k2->objectid)
131 if (k1.objectid < k2->objectid)
133 if (k1.flags > k2->flags)
135 if (k1.flags < k2->flags)
137 if (k1.offset > k2->offset)
139 if (k1.offset < k2->offset)
144 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
148 struct btrfs_node *parent = NULL;
149 struct btrfs_node *node = &path->nodes[level]->node;
151 u32 nritems = btrfs_header_nritems(&node->header);
153 if (path->nodes[level + 1])
154 parent = &path->nodes[level + 1]->node;
155 parent_slot = path->slots[level + 1];
156 BUG_ON(nritems == 0);
158 struct btrfs_disk_key *parent_key;
159 parent_key = &parent->ptrs[parent_slot].key;
160 BUG_ON(memcmp(parent_key, &node->ptrs[0].key,
161 sizeof(struct btrfs_disk_key)));
162 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
163 btrfs_header_blocknr(&node->header));
165 BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
166 for (i = 0; nritems > 1 && i < nritems - 2; i++) {
167 struct btrfs_key cpukey;
168 btrfs_disk_key_to_cpu(&cpukey, &node->ptrs[i + 1].key);
169 BUG_ON(btrfs_comp_keys(&node->ptrs[i].key, &cpukey) >= 0);
174 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
178 struct btrfs_leaf *leaf = &path->nodes[level]->leaf;
179 struct btrfs_node *parent = NULL;
181 u32 nritems = btrfs_header_nritems(&leaf->header);
183 if (path->nodes[level + 1])
184 parent = &path->nodes[level + 1]->node;
185 parent_slot = path->slots[level + 1];
186 BUG_ON(btrfs_leaf_free_space(root, leaf) < 0);
192 struct btrfs_disk_key *parent_key;
193 parent_key = &parent->ptrs[parent_slot].key;
194 BUG_ON(memcmp(parent_key, &leaf->items[0].key,
195 sizeof(struct btrfs_disk_key)));
196 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
197 btrfs_header_blocknr(&leaf->header));
199 for (i = 0; nritems > 1 && i < nritems - 2; i++) {
200 struct btrfs_key cpukey;
201 btrfs_disk_key_to_cpu(&cpukey, &leaf->items[i + 1].key);
202 BUG_ON(btrfs_comp_keys(&leaf->items[i].key,
204 BUG_ON(btrfs_item_offset(leaf->items + i) !=
205 btrfs_item_end(leaf->items + i + 1));
207 BUG_ON(btrfs_item_offset(leaf->items + i) +
208 btrfs_item_size(leaf->items + i) !=
209 BTRFS_LEAF_DATA_SIZE(root));
215 static int check_block(struct btrfs_root *root, struct btrfs_path *path,
219 return check_leaf(root, path, level);
220 return check_node(root, path, level);
224 * search for key in the array p. items p are item_size apart
225 * and there are 'max' items in p
226 * the slot in the array is returned via slot, and it points to
227 * the place where you would insert key if it is not found in
230 * slot may point to max if the key is bigger than all of the keys
232 static int generic_bin_search(char *p, int item_size, struct btrfs_key *key,
239 struct btrfs_disk_key *tmp;
242 mid = (low + high) / 2;
243 tmp = (struct btrfs_disk_key *)(p + mid * item_size);
244 ret = btrfs_comp_keys(tmp, key);
260 * simple bin_search frontend that does the right thing for
263 static int bin_search(struct btrfs_node *c, struct btrfs_key *key, int *slot)
265 if (btrfs_is_leaf(c)) {
266 struct btrfs_leaf *l = (struct btrfs_leaf *)c;
267 return generic_bin_search((void *)l->items,
268 sizeof(struct btrfs_item),
269 key, btrfs_header_nritems(&c->header),
272 return generic_bin_search((void *)c->ptrs,
273 sizeof(struct btrfs_key_ptr),
274 key, btrfs_header_nritems(&c->header),
280 static struct btrfs_buffer *read_node_slot(struct btrfs_root *root,
281 struct btrfs_buffer *parent_buf,
284 struct btrfs_node *node = &parent_buf->node;
287 if (slot >= btrfs_header_nritems(&node->header))
289 return read_tree_block(root, btrfs_node_blockptr(node, slot));
292 static int balance_level(struct btrfs_trans_handle *trans, struct btrfs_root
293 *root, struct btrfs_path *path, int level)
295 struct btrfs_buffer *right_buf;
296 struct btrfs_buffer *mid_buf;
297 struct btrfs_buffer *left_buf;
298 struct btrfs_buffer *parent_buf = NULL;
299 struct btrfs_node *right = NULL;
300 struct btrfs_node *mid;
301 struct btrfs_node *left = NULL;
302 struct btrfs_node *parent = NULL;
306 int orig_slot = path->slots[level];
312 mid_buf = path->nodes[level];
313 mid = &mid_buf->node;
314 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
316 if (level < BTRFS_MAX_LEVEL - 1)
317 parent_buf = path->nodes[level + 1];
318 pslot = path->slots[level + 1];
321 * deal with the case where there is only one pointer in the root
322 * by promoting the node below to a root
325 struct btrfs_buffer *child;
326 u64 blocknr = mid_buf->blocknr;
328 if (btrfs_header_nritems(&mid->header) != 1)
331 /* promote the child to a root */
332 child = read_node_slot(root, mid_buf, 0);
335 path->nodes[level] = NULL;
336 /* once for the path */
337 btrfs_block_release(root, mid_buf);
338 /* once for the root ptr */
339 btrfs_block_release(root, mid_buf);
340 clean_tree_block(trans, root, mid_buf);
341 return btrfs_free_extent(trans, root, blocknr, 1, 1);
343 parent = &parent_buf->node;
345 if (btrfs_header_nritems(&mid->header) >
346 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
349 left_buf = read_node_slot(root, parent_buf, pslot - 1);
350 right_buf = read_node_slot(root, parent_buf, pslot + 1);
352 /* first, try to make some room in the middle buffer */
354 btrfs_cow_block(trans, root, left_buf, parent_buf, pslot - 1,
356 left = &left_buf->node;
357 orig_slot += btrfs_header_nritems(&left->header);
358 wret = push_node_left(trans, root, left_buf, mid_buf);
364 * then try to empty the right most buffer into the middle
367 btrfs_cow_block(trans, root, right_buf, parent_buf, pslot + 1,
369 right = &right_buf->node;
370 wret = push_node_left(trans, root, mid_buf, right_buf);
373 if (btrfs_header_nritems(&right->header) == 0) {
374 u64 blocknr = right_buf->blocknr;
375 btrfs_block_release(root, right_buf);
376 clean_tree_block(trans, root, right_buf);
379 wret = del_ptr(trans, root, path, level + 1, pslot +
383 wret = btrfs_free_extent(trans, root, blocknr, 1, 1);
387 memcpy(&parent->ptrs[pslot + 1].key,
389 sizeof(struct btrfs_disk_key));
390 BUG_ON(list_empty(&parent_buf->dirty));
393 if (btrfs_header_nritems(&mid->header) == 1) {
395 * we're not allowed to leave a node with one item in the
396 * tree during a delete. A deletion from lower in the tree
397 * could try to delete the only pointer in this node.
398 * So, pull some keys from the left.
399 * There has to be a left pointer at this point because
400 * otherwise we would have pulled some pointers from the
404 wret = balance_node_right(trans, root, mid_buf, left_buf);
409 if (btrfs_header_nritems(&mid->header) == 0) {
410 /* we've managed to empty the middle node, drop it */
411 u64 blocknr = mid_buf->blocknr;
412 btrfs_block_release(root, mid_buf);
413 clean_tree_block(trans, root, mid_buf);
416 wret = del_ptr(trans, root, path, level + 1, pslot);
419 wret = btrfs_free_extent(trans, root, blocknr, 1, 1);
423 /* update the parent key to reflect our changes */
424 memcpy(&parent->ptrs[pslot].key, &mid->ptrs[0].key,
425 sizeof(struct btrfs_disk_key));
426 BUG_ON(list_empty(&parent_buf->dirty));
429 /* update the path */
431 if (btrfs_header_nritems(&left->header) > orig_slot) {
432 left_buf->count++; // released below
433 path->nodes[level] = left_buf;
434 path->slots[level + 1] -= 1;
435 path->slots[level] = orig_slot;
437 btrfs_block_release(root, mid_buf);
439 orig_slot -= btrfs_header_nritems(&left->header);
440 path->slots[level] = orig_slot;
443 /* double check we haven't messed things up */
444 check_block(root, path, level);
445 if (orig_ptr != btrfs_node_blockptr(&path->nodes[level]->node,
450 btrfs_block_release(root, right_buf);
452 btrfs_block_release(root, left_buf);
457 * look for key in the tree. path is filled in with nodes along the way
458 * if key is found, we return zero and you can find the item in the leaf
459 * level of the path (level 0)
461 * If the key isn't found, the path points to the slot where it should
462 * be inserted, and 1 is returned. If there are other errors during the
463 * search a negative error number is returned.
465 * if ins_len > 0, nodes and leaves will be split as we walk down the
466 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
469 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
470 *root, struct btrfs_key *key, struct btrfs_path *p, int
473 struct btrfs_buffer *b;
474 struct btrfs_buffer *cow_buf;
475 struct btrfs_node *c;
484 level = btrfs_header_level(&b->node.header);
487 wret = btrfs_cow_block(trans, root, b, p->nodes[level +
488 1], p->slots[level + 1],
492 BUG_ON(!cow && ins_len);
495 ret = check_block(root, p, level);
498 ret = bin_search(c, key, &slot);
499 if (!btrfs_is_leaf(c)) {
502 p->slots[level] = slot;
503 if (ins_len > 0 && btrfs_header_nritems(&c->header) ==
504 BTRFS_NODEPTRS_PER_BLOCK(root)) {
505 int sret = split_node(trans, root, p, level);
511 slot = p->slots[level];
512 } else if (ins_len < 0) {
513 int sret = balance_level(trans, root, p,
521 slot = p->slots[level];
522 BUG_ON(btrfs_header_nritems(&c->header) == 1);
524 b = read_tree_block(root, btrfs_node_blockptr(c, slot));
526 struct btrfs_leaf *l = (struct btrfs_leaf *)c;
527 p->slots[level] = slot;
528 if (ins_len > 0 && btrfs_leaf_free_space(root, l) <
529 sizeof(struct btrfs_item) + ins_len) {
530 int sret = split_leaf(trans, root, p, ins_len);
535 BUG_ON(root->node->count == 1);
539 BUG_ON(root->node->count == 1);
544 * adjust the pointers going up the tree, starting at level
545 * making sure the right key of each node is points to 'key'.
546 * This is used after shifting pointers to the left, so it stops
547 * fixing up pointers when a given leaf/node is not in slot 0 of the
550 * If this fails to write a tree block, it returns -1, but continues
551 * fixing up the blocks in ram so the tree is consistent.
553 static int fixup_low_keys(struct btrfs_trans_handle *trans, struct btrfs_root
554 *root, struct btrfs_path *path, struct btrfs_disk_key
559 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
560 struct btrfs_node *t;
561 int tslot = path->slots[i];
564 t = &path->nodes[i]->node;
565 memcpy(&t->ptrs[tslot].key, key, sizeof(*key));
566 BUG_ON(list_empty(&path->nodes[i]->dirty));
574 * try to push data from one node into the next node left in the
577 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
578 * error, and > 0 if there was no room in the left hand block.
580 static int push_node_left(struct btrfs_trans_handle *trans, struct btrfs_root
581 *root, struct btrfs_buffer *dst_buf, struct
582 btrfs_buffer *src_buf)
584 struct btrfs_node *src = &src_buf->node;
585 struct btrfs_node *dst = &dst_buf->node;
591 src_nritems = btrfs_header_nritems(&src->header);
592 dst_nritems = btrfs_header_nritems(&dst->header);
593 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
594 if (push_items <= 0) {
598 if (src_nritems < push_items)
599 push_items = src_nritems;
601 memcpy(dst->ptrs + dst_nritems, src->ptrs,
602 push_items * sizeof(struct btrfs_key_ptr));
603 if (push_items < src_nritems) {
604 memmove(src->ptrs, src->ptrs + push_items,
605 (src_nritems - push_items) *
606 sizeof(struct btrfs_key_ptr));
608 btrfs_set_header_nritems(&src->header, src_nritems - push_items);
609 btrfs_set_header_nritems(&dst->header, dst_nritems + push_items);
610 BUG_ON(list_empty(&src_buf->dirty));
611 BUG_ON(list_empty(&dst_buf->dirty));
616 * try to push data from one node into the next node right in the
619 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
620 * error, and > 0 if there was no room in the right hand block.
622 * this will only push up to 1/2 the contents of the left node over
624 static int balance_node_right(struct btrfs_trans_handle *trans, struct
625 btrfs_root *root, struct btrfs_buffer *dst_buf,
626 struct btrfs_buffer *src_buf)
628 struct btrfs_node *src = &src_buf->node;
629 struct btrfs_node *dst = &dst_buf->node;
636 src_nritems = btrfs_header_nritems(&src->header);
637 dst_nritems = btrfs_header_nritems(&dst->header);
638 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
639 if (push_items <= 0) {
643 max_push = src_nritems / 2 + 1;
644 /* don't try to empty the node */
645 if (max_push > src_nritems)
647 if (max_push < push_items)
648 push_items = max_push;
650 memmove(dst->ptrs + push_items, dst->ptrs,
651 dst_nritems * sizeof(struct btrfs_key_ptr));
652 memcpy(dst->ptrs, src->ptrs + src_nritems - push_items,
653 push_items * sizeof(struct btrfs_key_ptr));
655 btrfs_set_header_nritems(&src->header, src_nritems - push_items);
656 btrfs_set_header_nritems(&dst->header, dst_nritems + push_items);
658 BUG_ON(list_empty(&src_buf->dirty));
659 BUG_ON(list_empty(&dst_buf->dirty));
664 * helper function to insert a new root level in the tree.
665 * A new node is allocated, and a single item is inserted to
666 * point to the existing root
668 * returns zero on success or < 0 on failure.
670 static int insert_new_root(struct btrfs_trans_handle *trans, struct btrfs_root
671 *root, struct btrfs_path *path, int level)
673 struct btrfs_buffer *t;
674 struct btrfs_node *lower;
675 struct btrfs_node *c;
676 struct btrfs_disk_key *lower_key;
678 BUG_ON(path->nodes[level]);
679 BUG_ON(path->nodes[level-1] != root->node);
681 t = btrfs_alloc_free_block(trans, root);
683 memset(c, 0, root->blocksize);
684 btrfs_set_header_nritems(&c->header, 1);
685 btrfs_set_header_level(&c->header, level);
686 btrfs_set_header_blocknr(&c->header, t->blocknr);
687 btrfs_set_header_owner(&c->header, root->root_key.objectid);
688 lower = &path->nodes[level-1]->node;
689 if (btrfs_is_leaf(lower))
690 lower_key = &((struct btrfs_leaf *)lower)->items[0].key;
692 lower_key = &lower->ptrs[0].key;
693 memcpy(&c->ptrs[0].key, lower_key, sizeof(struct btrfs_disk_key));
694 btrfs_set_node_blockptr(c, 0, path->nodes[level - 1]->blocknr);
695 /* the super has an extra ref to root->node */
696 btrfs_block_release(root, root->node);
699 path->nodes[level] = t;
700 path->slots[level] = 0;
705 * worker function to insert a single pointer in a node.
706 * the node should have enough room for the pointer already
708 * slot and level indicate where you want the key to go, and
709 * blocknr is the block the key points to.
711 * returns zero on success and < 0 on any error
713 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
714 *root, struct btrfs_path *path, struct btrfs_disk_key
715 *key, u64 blocknr, int slot, int level)
717 struct btrfs_node *lower;
720 BUG_ON(!path->nodes[level]);
721 lower = &path->nodes[level]->node;
722 nritems = btrfs_header_nritems(&lower->header);
725 if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
727 if (slot != nritems) {
728 memmove(lower->ptrs + slot + 1, lower->ptrs + slot,
729 (nritems - slot) * sizeof(struct btrfs_key_ptr));
731 memcpy(&lower->ptrs[slot].key, key, sizeof(struct btrfs_disk_key));
732 btrfs_set_node_blockptr(lower, slot, blocknr);
733 btrfs_set_header_nritems(&lower->header, nritems + 1);
734 BUG_ON(list_empty(&path->nodes[level]->dirty));
739 * split the node at the specified level in path in two.
740 * The path is corrected to point to the appropriate node after the split
742 * Before splitting this tries to make some room in the node by pushing
743 * left and right, if either one works, it returns right away.
745 * returns 0 on success and < 0 on failure
747 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
748 *root, struct btrfs_path *path, int level)
750 struct btrfs_buffer *t;
751 struct btrfs_node *c;
752 struct btrfs_buffer *split_buffer;
753 struct btrfs_node *split;
759 t = path->nodes[level];
761 if (t == root->node) {
762 /* trying to split the root, lets make a new one */
763 ret = insert_new_root(trans, root, path, level + 1);
767 c_nritems = btrfs_header_nritems(&c->header);
768 split_buffer = btrfs_alloc_free_block(trans, root);
769 split = &split_buffer->node;
770 btrfs_set_header_flags(&split->header, btrfs_header_flags(&c->header));
771 btrfs_set_header_level(&split->header, btrfs_header_level(&c->header));
772 btrfs_set_header_blocknr(&split->header, split_buffer->blocknr);
773 btrfs_set_header_owner(&split->header, root->root_key.objectid);
774 mid = (c_nritems + 1) / 2;
775 memcpy(split->ptrs, c->ptrs + mid,
776 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
777 btrfs_set_header_nritems(&split->header, c_nritems - mid);
778 btrfs_set_header_nritems(&c->header, mid);
781 BUG_ON(list_empty(&t->dirty));
782 wret = insert_ptr(trans, root, path, &split->ptrs[0].key,
783 split_buffer->blocknr, path->slots[level + 1] + 1,
788 if (path->slots[level] >= mid) {
789 path->slots[level] -= mid;
790 btrfs_block_release(root, t);
791 path->nodes[level] = split_buffer;
792 path->slots[level + 1] += 1;
794 btrfs_block_release(root, split_buffer);
800 * push some data in the path leaf to the right, trying to free up at
801 * least data_size bytes. returns zero if the push worked, nonzero otherwise
803 * returns 1 if the push failed because the other node didn't have enough
804 * room, 0 if everything worked out and < 0 if there were major errors.
806 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
807 *root, struct btrfs_path *path, int data_size)
809 struct btrfs_buffer *left_buf = path->nodes[0];
810 struct btrfs_leaf *left = &left_buf->leaf;
811 struct btrfs_leaf *right;
812 struct btrfs_buffer *right_buf;
813 struct btrfs_buffer *upper;
819 struct btrfs_item *item;
823 slot = path->slots[1];
824 if (!path->nodes[1]) {
827 upper = path->nodes[1];
828 if (slot >= btrfs_header_nritems(&upper->node.header) - 1) {
831 right_buf = read_tree_block(root, btrfs_node_blockptr(&upper->node,
833 right = &right_buf->leaf;
834 free_space = btrfs_leaf_free_space(root, right);
835 if (free_space < data_size + sizeof(struct btrfs_item)) {
836 btrfs_block_release(root, right_buf);
839 /* cow and double check */
840 btrfs_cow_block(trans, root, right_buf, upper, slot + 1, &right_buf);
841 right = &right_buf->leaf;
842 free_space = btrfs_leaf_free_space(root, right);
843 if (free_space < data_size + sizeof(struct btrfs_item)) {
844 btrfs_block_release(root, right_buf);
848 left_nritems = btrfs_header_nritems(&left->header);
849 for (i = left_nritems - 1; i >= 0; i--) {
850 item = left->items + i;
851 if (path->slots[0] == i)
852 push_space += data_size + sizeof(*item);
853 if (btrfs_item_size(item) + sizeof(*item) + push_space >
857 push_space += btrfs_item_size(item) + sizeof(*item);
859 if (push_items == 0) {
860 btrfs_block_release(root, right_buf);
863 right_nritems = btrfs_header_nritems(&right->header);
864 /* push left to right */
865 push_space = btrfs_item_end(left->items + left_nritems - push_items);
866 push_space -= leaf_data_end(root, left);
867 /* make room in the right data area */
868 memmove(btrfs_leaf_data(right) + leaf_data_end(root, right) -
869 push_space, btrfs_leaf_data(right) + leaf_data_end(root, right),
870 BTRFS_LEAF_DATA_SIZE(root) - leaf_data_end(root, right));
871 /* copy from the left data area */
872 memcpy(btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) - push_space,
873 btrfs_leaf_data(left) + leaf_data_end(root, left), push_space);
874 memmove(right->items + push_items, right->items,
875 right_nritems * sizeof(struct btrfs_item));
876 /* copy the items from left to right */
877 memcpy(right->items, left->items + left_nritems - push_items,
878 push_items * sizeof(struct btrfs_item));
880 /* update the item pointers */
881 right_nritems += push_items;
882 btrfs_set_header_nritems(&right->header, right_nritems);
883 push_space = BTRFS_LEAF_DATA_SIZE(root);
884 for (i = 0; i < right_nritems; i++) {
885 btrfs_set_item_offset(right->items + i, push_space -
886 btrfs_item_size(right->items + i));
887 push_space = btrfs_item_offset(right->items + i);
889 left_nritems -= push_items;
890 btrfs_set_header_nritems(&left->header, left_nritems);
892 BUG_ON(list_empty(&left_buf->dirty));
893 BUG_ON(list_empty(&right_buf->dirty));
894 memcpy(&upper->node.ptrs[slot + 1].key,
895 &right->items[0].key, sizeof(struct btrfs_disk_key));
896 BUG_ON(list_empty(&upper->dirty));
898 /* then fixup the leaf pointer in the path */
899 if (path->slots[0] >= left_nritems) {
900 path->slots[0] -= left_nritems;
901 btrfs_block_release(root, path->nodes[0]);
902 path->nodes[0] = right_buf;
905 btrfs_block_release(root, right_buf);
910 * push some data in the path leaf to the left, trying to free up at
911 * least data_size bytes. returns zero if the push worked, nonzero otherwise
913 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
914 *root, struct btrfs_path *path, int data_size)
916 struct btrfs_buffer *right_buf = path->nodes[0];
917 struct btrfs_leaf *right = &right_buf->leaf;
918 struct btrfs_buffer *t;
919 struct btrfs_leaf *left;
925 struct btrfs_item *item;
926 u32 old_left_nritems;
930 slot = path->slots[1];
934 if (!path->nodes[1]) {
937 t = read_tree_block(root, btrfs_node_blockptr(&path->nodes[1]->node,
940 free_space = btrfs_leaf_free_space(root, left);
941 if (free_space < data_size + sizeof(struct btrfs_item)) {
942 btrfs_block_release(root, t);
946 /* cow and double check */
947 btrfs_cow_block(trans, root, t, path->nodes[1], slot - 1, &t);
949 free_space = btrfs_leaf_free_space(root, left);
950 if (free_space < data_size + sizeof(struct btrfs_item)) {
951 btrfs_block_release(root, t);
955 for (i = 0; i < btrfs_header_nritems(&right->header); i++) {
956 item = right->items + i;
957 if (path->slots[0] == i)
958 push_space += data_size + sizeof(*item);
959 if (btrfs_item_size(item) + sizeof(*item) + push_space >
963 push_space += btrfs_item_size(item) + sizeof(*item);
965 if (push_items == 0) {
966 btrfs_block_release(root, t);
969 /* push data from right to left */
970 memcpy(left->items + btrfs_header_nritems(&left->header),
971 right->items, push_items * sizeof(struct btrfs_item));
972 push_space = BTRFS_LEAF_DATA_SIZE(root) -
973 btrfs_item_offset(right->items + push_items -1);
974 memcpy(btrfs_leaf_data(left) + leaf_data_end(root, left) - push_space,
975 btrfs_leaf_data(right) +
976 btrfs_item_offset(right->items + push_items - 1),
978 old_left_nritems = btrfs_header_nritems(&left->header);
979 BUG_ON(old_left_nritems < 0);
981 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
982 u32 ioff = btrfs_item_offset(left->items + i);
983 btrfs_set_item_offset(left->items + i, ioff -
984 (BTRFS_LEAF_DATA_SIZE(root) -
985 btrfs_item_offset(left->items +
986 old_left_nritems - 1)));
988 btrfs_set_header_nritems(&left->header, old_left_nritems + push_items);
990 /* fixup right node */
991 push_space = btrfs_item_offset(right->items + push_items - 1) -
992 leaf_data_end(root, right);
993 memmove(btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
994 push_space, btrfs_leaf_data(right) +
995 leaf_data_end(root, right), push_space);
996 memmove(right->items, right->items + push_items,
997 (btrfs_header_nritems(&right->header) - push_items) *
998 sizeof(struct btrfs_item));
999 btrfs_set_header_nritems(&right->header,
1000 btrfs_header_nritems(&right->header) -
1002 push_space = BTRFS_LEAF_DATA_SIZE(root);
1004 for (i = 0; i < btrfs_header_nritems(&right->header); i++) {
1005 btrfs_set_item_offset(right->items + i, push_space -
1006 btrfs_item_size(right->items + i));
1007 push_space = btrfs_item_offset(right->items + i);
1010 BUG_ON(list_empty(&t->dirty));
1011 BUG_ON(list_empty(&right_buf->dirty));
1013 wret = fixup_low_keys(trans, root, path, &right->items[0].key, 1);
1017 /* then fixup the leaf pointer in the path */
1018 if (path->slots[0] < push_items) {
1019 path->slots[0] += old_left_nritems;
1020 btrfs_block_release(root, path->nodes[0]);
1022 path->slots[1] -= 1;
1024 btrfs_block_release(root, t);
1025 path->slots[0] -= push_items;
1027 BUG_ON(path->slots[0] < 0);
1032 * split the path's leaf in two, making sure there is at least data_size
1033 * available for the resulting leaf level of the path.
1035 * returns 0 if all went well and < 0 on failure.
1037 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
1038 *root, struct btrfs_path *path, int data_size)
1040 struct btrfs_buffer *l_buf;
1041 struct btrfs_leaf *l;
1045 struct btrfs_leaf *right;
1046 struct btrfs_buffer *right_buffer;
1047 int space_needed = data_size + sizeof(struct btrfs_item);
1054 /* first try to make some room by pushing left and right */
1055 wret = push_leaf_left(trans, root, path, data_size);
1059 wret = push_leaf_right(trans, root, path, data_size);
1063 l_buf = path->nodes[0];
1066 /* did the pushes work? */
1067 if (btrfs_leaf_free_space(root, l) >=
1068 sizeof(struct btrfs_item) + data_size)
1071 if (!path->nodes[1]) {
1072 ret = insert_new_root(trans, root, path, 1);
1076 slot = path->slots[0];
1077 nritems = btrfs_header_nritems(&l->header);
1078 mid = (nritems + 1)/ 2;
1079 right_buffer = btrfs_alloc_free_block(trans, root);
1080 BUG_ON(!right_buffer);
1081 BUG_ON(mid == nritems);
1082 right = &right_buffer->leaf;
1083 memset(&right->header, 0, sizeof(right->header));
1085 /* FIXME, just alloc a new leaf here */
1086 if (leaf_space_used(l, mid, nritems - mid) + space_needed >
1087 BTRFS_LEAF_DATA_SIZE(root))
1090 /* FIXME, just alloc a new leaf here */
1091 if (leaf_space_used(l, 0, mid + 1) + space_needed >
1092 BTRFS_LEAF_DATA_SIZE(root))
1095 btrfs_set_header_nritems(&right->header, nritems - mid);
1096 btrfs_set_header_blocknr(&right->header, right_buffer->blocknr);
1097 btrfs_set_header_level(&right->header, 0);
1098 btrfs_set_header_owner(&right->header, root->root_key.objectid);
1099 data_copy_size = btrfs_item_end(l->items + mid) -
1100 leaf_data_end(root, l);
1101 memcpy(right->items, l->items + mid,
1102 (nritems - mid) * sizeof(struct btrfs_item));
1103 memcpy(btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
1104 data_copy_size, btrfs_leaf_data(l) +
1105 leaf_data_end(root, l), data_copy_size);
1106 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
1107 btrfs_item_end(l->items + mid);
1109 for (i = 0; i < btrfs_header_nritems(&right->header); i++) {
1110 u32 ioff = btrfs_item_offset(right->items + i);
1111 btrfs_set_item_offset(right->items + i, ioff + rt_data_off);
1114 btrfs_set_header_nritems(&l->header, mid);
1116 wret = insert_ptr(trans, root, path, &right->items[0].key,
1117 right_buffer->blocknr, path->slots[1] + 1, 1);
1120 BUG_ON(list_empty(&right_buffer->dirty));
1121 BUG_ON(list_empty(&l_buf->dirty));
1122 BUG_ON(path->slots[0] != slot);
1124 btrfs_block_release(root, path->nodes[0]);
1125 path->nodes[0] = right_buffer;
1126 path->slots[0] -= mid;
1127 path->slots[1] += 1;
1129 btrfs_block_release(root, right_buffer);
1130 BUG_ON(path->slots[0] < 0);
1135 * Given a key and some data, insert an item into the tree.
1136 * This does all the path init required, making room in the tree if needed.
1138 int btrfs_insert_empty_item(struct btrfs_trans_handle *trans, struct btrfs_root
1139 *root, struct btrfs_path *path, struct btrfs_key
1140 *cpu_key, u32 data_size)
1145 struct btrfs_leaf *leaf;
1146 struct btrfs_buffer *leaf_buf;
1148 unsigned int data_end;
1149 struct btrfs_disk_key disk_key;
1151 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
1153 /* create a root if there isn't one */
1156 ret = btrfs_search_slot(trans, root, cpu_key, path, data_size, 1);
1163 slot_orig = path->slots[0];
1164 leaf_buf = path->nodes[0];
1165 leaf = &leaf_buf->leaf;
1167 nritems = btrfs_header_nritems(&leaf->header);
1168 data_end = leaf_data_end(root, leaf);
1170 if (btrfs_leaf_free_space(root, leaf) <
1171 sizeof(struct btrfs_item) + data_size)
1174 slot = path->slots[0];
1176 if (slot != nritems) {
1178 unsigned int old_data = btrfs_item_end(leaf->items + slot);
1181 * item0..itemN ... dataN.offset..dataN.size .. data0.size
1183 /* first correct the data pointers */
1184 for (i = slot; i < nritems; i++) {
1185 u32 ioff = btrfs_item_offset(leaf->items + i);
1186 btrfs_set_item_offset(leaf->items + i,
1190 /* shift the items */
1191 memmove(leaf->items + slot + 1, leaf->items + slot,
1192 (nritems - slot) * sizeof(struct btrfs_item));
1194 /* shift the data */
1195 memmove(btrfs_leaf_data(leaf) + data_end - data_size,
1196 btrfs_leaf_data(leaf) +
1197 data_end, old_data - data_end);
1198 data_end = old_data;
1200 /* setup the item for the new data */
1201 memcpy(&leaf->items[slot].key, &disk_key,
1202 sizeof(struct btrfs_disk_key));
1203 btrfs_set_item_offset(leaf->items + slot, data_end - data_size);
1204 btrfs_set_item_size(leaf->items + slot, data_size);
1205 btrfs_set_header_nritems(&leaf->header, nritems + 1);
1209 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
1211 BUG_ON(list_empty(&leaf_buf->dirty));
1212 if (btrfs_leaf_free_space(root, leaf) < 0)
1214 check_leaf(root, path, 0);
1220 * Given a key and some data, insert an item into the tree.
1221 * This does all the path init required, making room in the tree if needed.
1223 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
1224 *root, struct btrfs_key *cpu_key, void *data, u32
1228 struct btrfs_path path;
1231 btrfs_init_path(&path);
1232 ret = btrfs_insert_empty_item(trans, root, &path, cpu_key, data_size);
1234 ptr = btrfs_item_ptr(&path.nodes[0]->leaf, path.slots[0], u8);
1235 memcpy(ptr, data, data_size);
1237 btrfs_release_path(root, &path);
1242 * delete the pointer from a given node.
1244 * If the delete empties a node, the node is removed from the tree,
1245 * continuing all the way the root if required. The root is converted into
1246 * a leaf if all the nodes are emptied.
1248 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1249 struct btrfs_path *path, int level, int slot)
1251 struct btrfs_node *node;
1252 struct btrfs_buffer *parent = path->nodes[level];
1257 node = &parent->node;
1258 nritems = btrfs_header_nritems(&node->header);
1259 if (slot != nritems -1) {
1260 memmove(node->ptrs + slot, node->ptrs + slot + 1,
1261 sizeof(struct btrfs_key_ptr) * (nritems - slot - 1));
1264 btrfs_set_header_nritems(&node->header, nritems);
1265 if (nritems == 0 && parent == root->node) {
1266 BUG_ON(btrfs_header_level(&root->node->node.header) != 1);
1267 /* just turn the root into a leaf and break */
1268 btrfs_set_header_level(&root->node->node.header, 0);
1269 } else if (slot == 0) {
1270 wret = fixup_low_keys(trans, root, path, &node->ptrs[0].key,
1275 BUG_ON(list_empty(&parent->dirty));
1280 * delete the item at the leaf level in path. If that empties
1281 * the leaf, remove it from the tree
1283 int btrfs_del_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1284 struct btrfs_path *path)
1287 struct btrfs_leaf *leaf;
1288 struct btrfs_buffer *leaf_buf;
1295 leaf_buf = path->nodes[0];
1296 leaf = &leaf_buf->leaf;
1297 slot = path->slots[0];
1298 doff = btrfs_item_offset(leaf->items + slot);
1299 dsize = btrfs_item_size(leaf->items + slot);
1300 nritems = btrfs_header_nritems(&leaf->header);
1302 if (slot != nritems - 1) {
1304 int data_end = leaf_data_end(root, leaf);
1305 memmove(btrfs_leaf_data(leaf) + data_end + dsize,
1306 btrfs_leaf_data(leaf) + data_end,
1308 for (i = slot + 1; i < nritems; i++) {
1309 u32 ioff = btrfs_item_offset(leaf->items + i);
1310 btrfs_set_item_offset(leaf->items + i, ioff + dsize);
1312 memmove(leaf->items + slot, leaf->items + slot + 1,
1313 sizeof(struct btrfs_item) *
1314 (nritems - slot - 1));
1316 btrfs_set_header_nritems(&leaf->header, nritems - 1);
1318 /* delete the leaf if we've emptied it */
1320 if (leaf_buf == root->node) {
1321 btrfs_set_header_level(&leaf->header, 0);
1322 BUG_ON(list_empty(&leaf_buf->dirty));
1324 clean_tree_block(trans, root, leaf_buf);
1325 wret = del_ptr(trans, root, path, 1, path->slots[1]);
1328 wret = btrfs_free_extent(trans, root,
1329 leaf_buf->blocknr, 1, 1);
1334 int used = leaf_space_used(leaf, 0, nritems);
1336 wret = fixup_low_keys(trans, root, path,
1337 &leaf->items[0].key, 1);
1341 BUG_ON(list_empty(&leaf_buf->dirty));
1343 /* delete the leaf if it is mostly empty */
1344 if (used < BTRFS_LEAF_DATA_SIZE(root) / 3) {
1345 /* push_leaf_left fixes the path.
1346 * make sure the path still points to our leaf
1347 * for possible call to del_ptr below
1349 slot = path->slots[1];
1351 wret = push_leaf_left(trans, root, path, 1);
1354 if (path->nodes[0] == leaf_buf &&
1355 btrfs_header_nritems(&leaf->header)) {
1356 wret = push_leaf_right(trans, root, path, 1);
1360 if (btrfs_header_nritems(&leaf->header) == 0) {
1361 u64 blocknr = leaf_buf->blocknr;
1362 clean_tree_block(trans, root, leaf_buf);
1363 wret = del_ptr(trans, root, path, 1, slot);
1366 btrfs_block_release(root, leaf_buf);
1367 wret = btrfs_free_extent(trans, root, blocknr,
1372 btrfs_block_release(root, leaf_buf);
1379 int btrfs_extend_item(struct btrfs_trans_handle *trans, struct btrfs_root
1380 *root, struct btrfs_path *path, u32 data_size)
1385 struct btrfs_leaf *leaf;
1386 struct btrfs_buffer *leaf_buf;
1388 unsigned int data_end;
1389 unsigned int old_data;
1390 unsigned int old_size;
1393 slot_orig = path->slots[0];
1394 leaf_buf = path->nodes[0];
1395 leaf = &leaf_buf->leaf;
1397 nritems = btrfs_header_nritems(&leaf->header);
1398 data_end = leaf_data_end(root, leaf);
1400 if (btrfs_leaf_free_space(root, leaf) < data_size)
1402 slot = path->slots[0];
1403 old_data = btrfs_item_end(leaf->items + slot);
1406 BUG_ON(slot >= nritems);
1409 * item0..itemN ... dataN.offset..dataN.size .. data0.size
1411 /* first correct the data pointers */
1412 for (i = slot; i < nritems; i++) {
1413 u32 ioff = btrfs_item_offset(leaf->items + i);
1414 btrfs_set_item_offset(leaf->items + i,
1417 /* shift the data */
1418 memmove(btrfs_leaf_data(leaf) + data_end - data_size,
1419 btrfs_leaf_data(leaf) + data_end, old_data - data_end);
1420 data_end = old_data;
1421 old_size = btrfs_item_size(leaf->items + slot);
1422 btrfs_set_item_size(leaf->items + slot, old_size + data_size);
1425 if (btrfs_leaf_free_space(root, leaf) < 0)
1427 check_leaf(root, path, 0);
1432 * walk up the tree as far as required to find the next leaf.
1433 * returns 0 if it found something or 1 if there are no greater leaves.
1434 * returns < 0 on io errors.
1436 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
1441 struct btrfs_buffer *c;
1442 struct btrfs_buffer *next = NULL;
1444 while(level < BTRFS_MAX_LEVEL) {
1445 if (!path->nodes[level])
1447 slot = path->slots[level] + 1;
1448 c = path->nodes[level];
1449 if (slot >= btrfs_header_nritems(&c->node.header)) {
1453 blocknr = btrfs_node_blockptr(&c->node, slot);
1455 btrfs_block_release(root, next);
1456 next = read_tree_block(root, blocknr);
1459 path->slots[level] = slot;
1462 c = path->nodes[level];
1463 btrfs_block_release(root, c);
1464 path->nodes[level] = next;
1465 path->slots[level] = 0;
1468 next = read_tree_block(root,
1469 btrfs_node_blockptr(&next->node, 0));