1 #include <linux/module.h>
4 #include "transaction.h"
6 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
7 *root, struct btrfs_path *path, int level);
8 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
9 *root, struct btrfs_key *ins_key,
10 struct btrfs_path *path, int data_size);
11 static int push_node_left(struct btrfs_trans_handle *trans, struct btrfs_root
12 *root, struct buffer_head *dst, struct buffer_head
14 static int balance_node_right(struct btrfs_trans_handle *trans, struct
15 btrfs_root *root, struct buffer_head *dst_buf,
16 struct buffer_head *src_buf);
17 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
18 struct btrfs_path *path, int level, int slot);
20 inline void btrfs_init_path(struct btrfs_path *p)
22 memset(p, 0, sizeof(*p));
25 struct btrfs_path *btrfs_alloc_path(void)
27 struct btrfs_path *path;
28 path = kmem_cache_alloc(btrfs_path_cachep, GFP_NOFS);
30 btrfs_init_path(path);
34 void btrfs_free_path(struct btrfs_path *p)
36 btrfs_release_path(NULL, p);
37 kmem_cache_free(btrfs_path_cachep, p);
40 void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
43 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
46 btrfs_block_release(root, p->nodes[i]);
48 memset(p, 0, sizeof(*p));
51 static int btrfs_cow_block(struct btrfs_trans_handle *trans, struct btrfs_root
52 *root, struct buffer_head *buf, struct buffer_head
53 *parent, int parent_slot, struct buffer_head
56 struct buffer_head *cow;
57 struct btrfs_node *cow_node;
59 if (btrfs_header_generation(btrfs_buffer_header(buf)) ==
64 cow = btrfs_alloc_free_block(trans, root);
65 cow_node = btrfs_buffer_node(cow);
66 if (buf->b_size != root->blocksize || cow->b_size != root->blocksize)
68 memcpy(cow_node, btrfs_buffer_node(buf), root->blocksize);
69 btrfs_set_header_blocknr(&cow_node->header, bh_blocknr(cow));
70 btrfs_set_header_generation(&cow_node->header, trans->transid);
71 btrfs_inc_ref(trans, root, buf);
72 if (buf == root->node) {
75 if (buf != root->commit_root) {
76 btrfs_free_extent(trans, root, bh_blocknr(buf), 1, 1);
78 btrfs_block_release(root, buf);
80 btrfs_set_node_blockptr(btrfs_buffer_node(parent), parent_slot,
82 btrfs_mark_buffer_dirty(parent);
83 btrfs_free_extent(trans, root, bh_blocknr(buf), 1, 1);
85 btrfs_block_release(root, buf);
86 mark_buffer_dirty(cow);
92 * The leaf data grows from end-to-front in the node.
93 * this returns the address of the start of the last item,
94 * which is the stop of the leaf data stack
96 static inline unsigned int leaf_data_end(struct btrfs_root *root,
97 struct btrfs_leaf *leaf)
99 u32 nr = btrfs_header_nritems(&leaf->header);
101 return BTRFS_LEAF_DATA_SIZE(root);
102 return btrfs_item_offset(leaf->items + nr - 1);
106 * compare two keys in a memcmp fashion
108 static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
112 btrfs_disk_key_to_cpu(&k1, disk);
114 if (k1.objectid > k2->objectid)
116 if (k1.objectid < k2->objectid)
118 if (k1.flags > k2->flags)
120 if (k1.flags < k2->flags)
122 if (k1.offset > k2->offset)
124 if (k1.offset < k2->offset)
129 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
133 struct btrfs_node *parent = NULL;
134 struct btrfs_node *node = btrfs_buffer_node(path->nodes[level]);
136 u32 nritems = btrfs_header_nritems(&node->header);
138 if (path->nodes[level + 1])
139 parent = btrfs_buffer_node(path->nodes[level + 1]);
140 parent_slot = path->slots[level + 1];
141 BUG_ON(nritems == 0);
143 struct btrfs_disk_key *parent_key;
144 parent_key = &parent->ptrs[parent_slot].key;
145 BUG_ON(memcmp(parent_key, &node->ptrs[0].key,
146 sizeof(struct btrfs_disk_key)));
147 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
148 btrfs_header_blocknr(&node->header));
150 BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
151 for (i = 0; nritems > 1 && i < nritems - 2; i++) {
152 struct btrfs_key cpukey;
153 btrfs_disk_key_to_cpu(&cpukey, &node->ptrs[i + 1].key);
154 BUG_ON(comp_keys(&node->ptrs[i].key, &cpukey) >= 0);
159 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
163 struct btrfs_leaf *leaf = btrfs_buffer_leaf(path->nodes[level]);
164 struct btrfs_node *parent = NULL;
166 u32 nritems = btrfs_header_nritems(&leaf->header);
168 if (path->nodes[level + 1])
169 parent = btrfs_buffer_node(path->nodes[level + 1]);
170 parent_slot = path->slots[level + 1];
171 BUG_ON(btrfs_leaf_free_space(root, leaf) < 0);
177 struct btrfs_disk_key *parent_key;
178 parent_key = &parent->ptrs[parent_slot].key;
179 BUG_ON(memcmp(parent_key, &leaf->items[0].key,
180 sizeof(struct btrfs_disk_key)));
181 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
182 btrfs_header_blocknr(&leaf->header));
184 for (i = 0; nritems > 1 && i < nritems - 2; i++) {
185 struct btrfs_key cpukey;
186 btrfs_disk_key_to_cpu(&cpukey, &leaf->items[i + 1].key);
187 BUG_ON(comp_keys(&leaf->items[i].key,
189 BUG_ON(btrfs_item_offset(leaf->items + i) !=
190 btrfs_item_end(leaf->items + i + 1));
192 BUG_ON(btrfs_item_offset(leaf->items + i) +
193 btrfs_item_size(leaf->items + i) !=
194 BTRFS_LEAF_DATA_SIZE(root));
200 static int check_block(struct btrfs_root *root, struct btrfs_path *path,
203 struct btrfs_node *node = btrfs_buffer_node(path->nodes[level]);
204 if (memcmp(node->header.fsid, root->fs_info->disk_super->fsid,
205 sizeof(node->header.fsid)))
208 return check_leaf(root, path, level);
209 return check_node(root, path, level);
213 * search for key in the array p. items p are item_size apart
214 * and there are 'max' items in p
215 * the slot in the array is returned via slot, and it points to
216 * the place where you would insert key if it is not found in
219 * slot may point to max if the key is bigger than all of the keys
221 static int generic_bin_search(char *p, int item_size, struct btrfs_key *key,
228 struct btrfs_disk_key *tmp;
231 mid = (low + high) / 2;
232 tmp = (struct btrfs_disk_key *)(p + mid * item_size);
233 ret = comp_keys(tmp, key);
249 * simple bin_search frontend that does the right thing for
252 static int bin_search(struct btrfs_node *c, struct btrfs_key *key, int *slot)
254 if (btrfs_is_leaf(c)) {
255 struct btrfs_leaf *l = (struct btrfs_leaf *)c;
256 return generic_bin_search((void *)l->items,
257 sizeof(struct btrfs_item),
258 key, btrfs_header_nritems(&c->header),
261 return generic_bin_search((void *)c->ptrs,
262 sizeof(struct btrfs_key_ptr),
263 key, btrfs_header_nritems(&c->header),
269 static struct buffer_head *read_node_slot(struct btrfs_root *root,
270 struct buffer_head *parent_buf,
273 struct btrfs_node *node = btrfs_buffer_node(parent_buf);
276 if (slot >= btrfs_header_nritems(&node->header))
278 return read_tree_block(root, btrfs_node_blockptr(node, slot));
281 static int balance_level(struct btrfs_trans_handle *trans, struct btrfs_root
282 *root, struct btrfs_path *path, int level)
284 struct buffer_head *right_buf;
285 struct buffer_head *mid_buf;
286 struct buffer_head *left_buf;
287 struct buffer_head *parent_buf = NULL;
288 struct btrfs_node *right = NULL;
289 struct btrfs_node *mid;
290 struct btrfs_node *left = NULL;
291 struct btrfs_node *parent = NULL;
295 int orig_slot = path->slots[level];
301 mid_buf = path->nodes[level];
302 mid = btrfs_buffer_node(mid_buf);
303 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
305 if (level < BTRFS_MAX_LEVEL - 1)
306 parent_buf = path->nodes[level + 1];
307 pslot = path->slots[level + 1];
310 * deal with the case where there is only one pointer in the root
311 * by promoting the node below to a root
314 struct buffer_head *child;
315 u64 blocknr = bh_blocknr(mid_buf);
317 if (btrfs_header_nritems(&mid->header) != 1)
320 /* promote the child to a root */
321 child = read_node_slot(root, mid_buf, 0);
324 path->nodes[level] = NULL;
325 clean_tree_block(trans, root, mid_buf);
326 wait_on_buffer(mid_buf);
327 /* once for the path */
328 btrfs_block_release(root, mid_buf);
329 /* once for the root ptr */
330 btrfs_block_release(root, mid_buf);
331 return btrfs_free_extent(trans, root, blocknr, 1, 1);
333 parent = btrfs_buffer_node(parent_buf);
335 if (btrfs_header_nritems(&mid->header) >
336 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
339 left_buf = read_node_slot(root, parent_buf, pslot - 1);
340 right_buf = read_node_slot(root, parent_buf, pslot + 1);
342 /* first, try to make some room in the middle buffer */
344 btrfs_cow_block(trans, root, left_buf, parent_buf, pslot - 1,
346 left = btrfs_buffer_node(left_buf);
347 orig_slot += btrfs_header_nritems(&left->header);
348 wret = push_node_left(trans, root, left_buf, mid_buf);
354 * then try to empty the right most buffer into the middle
357 btrfs_cow_block(trans, root, right_buf, parent_buf, pslot + 1,
359 right = btrfs_buffer_node(right_buf);
360 wret = push_node_left(trans, root, mid_buf, right_buf);
363 if (btrfs_header_nritems(&right->header) == 0) {
364 u64 blocknr = bh_blocknr(right_buf);
365 clean_tree_block(trans, root, right_buf);
366 wait_on_buffer(right_buf);
367 btrfs_block_release(root, right_buf);
370 wret = del_ptr(trans, root, path, level + 1, pslot +
374 wret = btrfs_free_extent(trans, root, blocknr, 1, 1);
378 btrfs_memcpy(root, parent,
379 &parent->ptrs[pslot + 1].key,
381 sizeof(struct btrfs_disk_key));
382 btrfs_mark_buffer_dirty(parent_buf);
385 if (btrfs_header_nritems(&mid->header) == 1) {
387 * we're not allowed to leave a node with one item in the
388 * tree during a delete. A deletion from lower in the tree
389 * could try to delete the only pointer in this node.
390 * So, pull some keys from the left.
391 * There has to be a left pointer at this point because
392 * otherwise we would have pulled some pointers from the
396 wret = balance_node_right(trans, root, mid_buf, left_buf);
401 if (btrfs_header_nritems(&mid->header) == 0) {
402 /* we've managed to empty the middle node, drop it */
403 u64 blocknr = bh_blocknr(mid_buf);
404 clean_tree_block(trans, root, mid_buf);
405 wait_on_buffer(mid_buf);
406 btrfs_block_release(root, mid_buf);
409 wret = del_ptr(trans, root, path, level + 1, pslot);
412 wret = btrfs_free_extent(trans, root, blocknr, 1, 1);
416 /* update the parent key to reflect our changes */
417 btrfs_memcpy(root, parent,
418 &parent->ptrs[pslot].key, &mid->ptrs[0].key,
419 sizeof(struct btrfs_disk_key));
420 btrfs_mark_buffer_dirty(parent_buf);
423 /* update the path */
425 if (btrfs_header_nritems(&left->header) > orig_slot) {
427 path->nodes[level] = left_buf;
428 path->slots[level + 1] -= 1;
429 path->slots[level] = orig_slot;
431 btrfs_block_release(root, mid_buf);
433 orig_slot -= btrfs_header_nritems(&left->header);
434 path->slots[level] = orig_slot;
437 /* double check we haven't messed things up */
438 check_block(root, path, level);
440 btrfs_node_blockptr(btrfs_buffer_node(path->nodes[level]),
445 btrfs_block_release(root, right_buf);
447 btrfs_block_release(root, left_buf);
451 /* returns zero if the push worked, non-zero otherwise */
452 static int push_nodes_for_insert(struct btrfs_trans_handle *trans,
453 struct btrfs_root *root,
454 struct btrfs_path *path, int level)
456 struct buffer_head *right_buf;
457 struct buffer_head *mid_buf;
458 struct buffer_head *left_buf;
459 struct buffer_head *parent_buf = NULL;
460 struct btrfs_node *right = NULL;
461 struct btrfs_node *mid;
462 struct btrfs_node *left = NULL;
463 struct btrfs_node *parent = NULL;
467 int orig_slot = path->slots[level];
473 mid_buf = path->nodes[level];
474 mid = btrfs_buffer_node(mid_buf);
475 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
477 if (level < BTRFS_MAX_LEVEL - 1)
478 parent_buf = path->nodes[level + 1];
479 pslot = path->slots[level + 1];
483 parent = btrfs_buffer_node(parent_buf);
485 left_buf = read_node_slot(root, parent_buf, pslot - 1);
487 /* first, try to make some room in the middle buffer */
490 left = btrfs_buffer_node(left_buf);
491 left_nr = btrfs_header_nritems(&left->header);
492 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
495 btrfs_cow_block(trans, root, left_buf, parent_buf,
496 pslot - 1, &left_buf);
497 left = btrfs_buffer_node(left_buf);
498 wret = push_node_left(trans, root, left_buf, mid_buf);
503 orig_slot += left_nr;
504 btrfs_memcpy(root, parent,
505 &parent->ptrs[pslot].key,
507 sizeof(struct btrfs_disk_key));
508 btrfs_mark_buffer_dirty(parent_buf);
509 if (btrfs_header_nritems(&left->header) > orig_slot) {
510 path->nodes[level] = left_buf;
511 path->slots[level + 1] -= 1;
512 path->slots[level] = orig_slot;
513 btrfs_block_release(root, mid_buf);
516 btrfs_header_nritems(&left->header);
517 path->slots[level] = orig_slot;
518 btrfs_block_release(root, left_buf);
520 check_node(root, path, level);
523 btrfs_block_release(root, left_buf);
525 right_buf = read_node_slot(root, parent_buf, pslot + 1);
528 * then try to empty the right most buffer into the middle
532 right = btrfs_buffer_node(right_buf);
533 right_nr = btrfs_header_nritems(&right->header);
534 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
537 btrfs_cow_block(trans, root, right_buf,
538 parent_buf, pslot + 1, &right_buf);
539 right = btrfs_buffer_node(right_buf);
540 wret = balance_node_right(trans, root,
546 btrfs_memcpy(root, parent,
547 &parent->ptrs[pslot + 1].key,
549 sizeof(struct btrfs_disk_key));
550 btrfs_mark_buffer_dirty(parent_buf);
551 if (btrfs_header_nritems(&mid->header) <= orig_slot) {
552 path->nodes[level] = right_buf;
553 path->slots[level + 1] += 1;
554 path->slots[level] = orig_slot -
555 btrfs_header_nritems(&mid->header);
556 btrfs_block_release(root, mid_buf);
558 btrfs_block_release(root, right_buf);
560 check_node(root, path, level);
563 btrfs_block_release(root, right_buf);
565 check_node(root, path, level);
570 * look for key in the tree. path is filled in with nodes along the way
571 * if key is found, we return zero and you can find the item in the leaf
572 * level of the path (level 0)
574 * If the key isn't found, the path points to the slot where it should
575 * be inserted, and 1 is returned. If there are other errors during the
576 * search a negative error number is returned.
578 * if ins_len > 0, nodes and leaves will be split as we walk down the
579 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
582 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
583 *root, struct btrfs_key *key, struct btrfs_path *p, int
586 struct buffer_head *b;
587 struct buffer_head *cow_buf;
588 struct btrfs_node *c;
593 WARN_ON(p->nodes[0] != NULL);
594 WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
599 c = btrfs_buffer_node(b);
600 level = btrfs_header_level(&c->header);
603 wret = btrfs_cow_block(trans, root, b,
608 c = btrfs_buffer_node(b);
610 BUG_ON(!cow && ins_len);
611 if (level != btrfs_header_level(&c->header))
613 level = btrfs_header_level(&c->header);
615 ret = check_block(root, p, level);
618 ret = bin_search(c, key, &slot);
619 if (!btrfs_is_leaf(c)) {
622 p->slots[level] = slot;
623 if (ins_len > 0 && btrfs_header_nritems(&c->header) >=
624 BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
625 int sret = split_node(trans, root, p, level);
630 c = btrfs_buffer_node(b);
631 slot = p->slots[level];
632 } else if (ins_len < 0) {
633 int sret = balance_level(trans, root, p,
640 c = btrfs_buffer_node(b);
641 slot = p->slots[level];
642 BUG_ON(btrfs_header_nritems(&c->header) == 1);
644 b = read_tree_block(root, btrfs_node_blockptr(c, slot));
646 struct btrfs_leaf *l = (struct btrfs_leaf *)c;
647 p->slots[level] = slot;
648 if (ins_len > 0 && btrfs_leaf_free_space(root, l) <
649 sizeof(struct btrfs_item) + ins_len) {
650 int sret = split_leaf(trans, root, key,
663 * adjust the pointers going up the tree, starting at level
664 * making sure the right key of each node is points to 'key'.
665 * This is used after shifting pointers to the left, so it stops
666 * fixing up pointers when a given leaf/node is not in slot 0 of the
669 * If this fails to write a tree block, it returns -1, but continues
670 * fixing up the blocks in ram so the tree is consistent.
672 static int fixup_low_keys(struct btrfs_trans_handle *trans, struct btrfs_root
673 *root, struct btrfs_path *path, struct btrfs_disk_key
678 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
679 struct btrfs_node *t;
680 int tslot = path->slots[i];
683 t = btrfs_buffer_node(path->nodes[i]);
684 btrfs_memcpy(root, t, &t->ptrs[tslot].key, key, sizeof(*key));
685 btrfs_mark_buffer_dirty(path->nodes[i]);
693 * try to push data from one node into the next node left in the
696 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
697 * error, and > 0 if there was no room in the left hand block.
699 static int push_node_left(struct btrfs_trans_handle *trans, struct btrfs_root
700 *root, struct buffer_head *dst_buf, struct
701 buffer_head *src_buf)
703 struct btrfs_node *src = btrfs_buffer_node(src_buf);
704 struct btrfs_node *dst = btrfs_buffer_node(dst_buf);
710 src_nritems = btrfs_header_nritems(&src->header);
711 dst_nritems = btrfs_header_nritems(&dst->header);
712 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
713 if (push_items <= 0) {
717 if (src_nritems < push_items)
718 push_items = src_nritems;
720 btrfs_memcpy(root, dst, dst->ptrs + dst_nritems, src->ptrs,
721 push_items * sizeof(struct btrfs_key_ptr));
722 if (push_items < src_nritems) {
723 btrfs_memmove(root, src, src->ptrs, src->ptrs + push_items,
724 (src_nritems - push_items) *
725 sizeof(struct btrfs_key_ptr));
727 btrfs_set_header_nritems(&src->header, src_nritems - push_items);
728 btrfs_set_header_nritems(&dst->header, dst_nritems + push_items);
729 btrfs_mark_buffer_dirty(src_buf);
730 btrfs_mark_buffer_dirty(dst_buf);
735 * try to push data from one node into the next node right in the
738 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
739 * error, and > 0 if there was no room in the right hand block.
741 * this will only push up to 1/2 the contents of the left node over
743 static int balance_node_right(struct btrfs_trans_handle *trans, struct
744 btrfs_root *root, struct buffer_head *dst_buf,
745 struct buffer_head *src_buf)
747 struct btrfs_node *src = btrfs_buffer_node(src_buf);
748 struct btrfs_node *dst = btrfs_buffer_node(dst_buf);
755 src_nritems = btrfs_header_nritems(&src->header);
756 dst_nritems = btrfs_header_nritems(&dst->header);
757 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
758 if (push_items <= 0) {
762 max_push = src_nritems / 2 + 1;
763 /* don't try to empty the node */
764 if (max_push > src_nritems)
766 if (max_push < push_items)
767 push_items = max_push;
769 btrfs_memmove(root, dst, dst->ptrs + push_items, dst->ptrs,
770 dst_nritems * sizeof(struct btrfs_key_ptr));
772 btrfs_memcpy(root, dst, dst->ptrs,
773 src->ptrs + src_nritems - push_items,
774 push_items * sizeof(struct btrfs_key_ptr));
776 btrfs_set_header_nritems(&src->header, src_nritems - push_items);
777 btrfs_set_header_nritems(&dst->header, dst_nritems + push_items);
779 btrfs_mark_buffer_dirty(src_buf);
780 btrfs_mark_buffer_dirty(dst_buf);
785 * helper function to insert a new root level in the tree.
786 * A new node is allocated, and a single item is inserted to
787 * point to the existing root
789 * returns zero on success or < 0 on failure.
791 static int insert_new_root(struct btrfs_trans_handle *trans, struct btrfs_root
792 *root, struct btrfs_path *path, int level)
794 struct buffer_head *t;
795 struct btrfs_node *lower;
796 struct btrfs_node *c;
797 struct btrfs_disk_key *lower_key;
799 BUG_ON(path->nodes[level]);
800 BUG_ON(path->nodes[level-1] != root->node);
802 t = btrfs_alloc_free_block(trans, root);
803 c = btrfs_buffer_node(t);
804 memset(c, 0, root->blocksize);
805 btrfs_set_header_nritems(&c->header, 1);
806 btrfs_set_header_level(&c->header, level);
807 btrfs_set_header_blocknr(&c->header, bh_blocknr(t));
808 btrfs_set_header_generation(&c->header, trans->transid);
809 lower = btrfs_buffer_node(path->nodes[level-1]);
810 memcpy(c->header.fsid, root->fs_info->disk_super->fsid,
811 sizeof(c->header.fsid));
812 if (btrfs_is_leaf(lower))
813 lower_key = &((struct btrfs_leaf *)lower)->items[0].key;
815 lower_key = &lower->ptrs[0].key;
816 btrfs_memcpy(root, c, &c->ptrs[0].key, lower_key,
817 sizeof(struct btrfs_disk_key));
818 btrfs_set_node_blockptr(c, 0, bh_blocknr(path->nodes[level - 1]));
820 btrfs_mark_buffer_dirty(t);
822 /* the super has an extra ref to root->node */
823 btrfs_block_release(root, root->node);
826 path->nodes[level] = t;
827 path->slots[level] = 0;
832 * worker function to insert a single pointer in a node.
833 * the node should have enough room for the pointer already
835 * slot and level indicate where you want the key to go, and
836 * blocknr is the block the key points to.
838 * returns zero on success and < 0 on any error
840 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
841 *root, struct btrfs_path *path, struct btrfs_disk_key
842 *key, u64 blocknr, int slot, int level)
844 struct btrfs_node *lower;
847 BUG_ON(!path->nodes[level]);
848 lower = btrfs_buffer_node(path->nodes[level]);
849 nritems = btrfs_header_nritems(&lower->header);
852 if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
854 if (slot != nritems) {
855 btrfs_memmove(root, lower, lower->ptrs + slot + 1,
857 (nritems - slot) * sizeof(struct btrfs_key_ptr));
859 btrfs_memcpy(root, lower, &lower->ptrs[slot].key,
860 key, sizeof(struct btrfs_disk_key));
861 btrfs_set_node_blockptr(lower, slot, blocknr);
862 btrfs_set_header_nritems(&lower->header, nritems + 1);
863 btrfs_mark_buffer_dirty(path->nodes[level]);
868 * split the node at the specified level in path in two.
869 * The path is corrected to point to the appropriate node after the split
871 * Before splitting this tries to make some room in the node by pushing
872 * left and right, if either one works, it returns right away.
874 * returns 0 on success and < 0 on failure
876 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
877 *root, struct btrfs_path *path, int level)
879 struct buffer_head *t;
880 struct btrfs_node *c;
881 struct buffer_head *split_buffer;
882 struct btrfs_node *split;
888 t = path->nodes[level];
889 c = btrfs_buffer_node(t);
890 if (t == root->node) {
891 /* trying to split the root, lets make a new one */
892 ret = insert_new_root(trans, root, path, level + 1);
896 ret = push_nodes_for_insert(trans, root, path, level);
897 t = path->nodes[level];
898 c = btrfs_buffer_node(t);
900 btrfs_header_nritems(&c->header) <
901 BTRFS_NODEPTRS_PER_BLOCK(root) - 1)
905 c_nritems = btrfs_header_nritems(&c->header);
906 split_buffer = btrfs_alloc_free_block(trans, root);
907 split = btrfs_buffer_node(split_buffer);
908 btrfs_set_header_flags(&split->header, btrfs_header_flags(&c->header));
909 btrfs_set_header_level(&split->header, btrfs_header_level(&c->header));
910 btrfs_set_header_blocknr(&split->header, bh_blocknr(split_buffer));
911 btrfs_set_header_generation(&split->header, trans->transid);
912 memcpy(split->header.fsid, root->fs_info->disk_super->fsid,
913 sizeof(split->header.fsid));
914 mid = (c_nritems + 1) / 2;
915 btrfs_memcpy(root, split, split->ptrs, c->ptrs + mid,
916 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
917 btrfs_set_header_nritems(&split->header, c_nritems - mid);
918 btrfs_set_header_nritems(&c->header, mid);
921 btrfs_mark_buffer_dirty(t);
922 btrfs_mark_buffer_dirty(split_buffer);
923 wret = insert_ptr(trans, root, path, &split->ptrs[0].key,
924 bh_blocknr(split_buffer), path->slots[level + 1] + 1,
929 if (path->slots[level] >= mid) {
930 path->slots[level] -= mid;
931 btrfs_block_release(root, t);
932 path->nodes[level] = split_buffer;
933 path->slots[level + 1] += 1;
935 btrfs_block_release(root, split_buffer);
941 * how many bytes are required to store the items in a leaf. start
942 * and nr indicate which items in the leaf to check. This totals up the
943 * space used both by the item structs and the item data
945 static int leaf_space_used(struct btrfs_leaf *l, int start, int nr)
948 int nritems = btrfs_header_nritems(&l->header);
949 int end = min(nritems, start + nr) - 1;
953 data_len = btrfs_item_end(l->items + start);
954 data_len = data_len - btrfs_item_offset(l->items + end);
955 data_len += sizeof(struct btrfs_item) * nr;
956 WARN_ON(data_len < 0);
961 * The space between the end of the leaf items and
962 * the start of the leaf data. IOW, how much room
963 * the leaf has left for both items and data
965 int btrfs_leaf_free_space(struct btrfs_root *root, struct btrfs_leaf *leaf)
967 int nritems = btrfs_header_nritems(&leaf->header);
968 return BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
972 * push some data in the path leaf to the right, trying to free up at
973 * least data_size bytes. returns zero if the push worked, nonzero otherwise
975 * returns 1 if the push failed because the other node didn't have enough
976 * room, 0 if everything worked out and < 0 if there were major errors.
978 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
979 *root, struct btrfs_path *path, int data_size)
981 struct buffer_head *left_buf = path->nodes[0];
982 struct btrfs_leaf *left = btrfs_buffer_leaf(left_buf);
983 struct btrfs_leaf *right;
984 struct buffer_head *right_buf;
985 struct buffer_head *upper;
986 struct btrfs_node *upper_node;
992 struct btrfs_item *item;
996 slot = path->slots[1];
997 if (!path->nodes[1]) {
1000 upper = path->nodes[1];
1001 upper_node = btrfs_buffer_node(upper);
1002 if (slot >= btrfs_header_nritems(&upper_node->header) - 1) {
1005 right_buf = read_tree_block(root,
1006 btrfs_node_blockptr(btrfs_buffer_node(upper), slot + 1));
1007 right = btrfs_buffer_leaf(right_buf);
1008 free_space = btrfs_leaf_free_space(root, right);
1009 if (free_space < data_size + sizeof(struct btrfs_item)) {
1010 btrfs_block_release(root, right_buf);
1013 /* cow and double check */
1014 btrfs_cow_block(trans, root, right_buf, upper, slot + 1, &right_buf);
1015 right = btrfs_buffer_leaf(right_buf);
1016 free_space = btrfs_leaf_free_space(root, right);
1017 if (free_space < data_size + sizeof(struct btrfs_item)) {
1018 btrfs_block_release(root, right_buf);
1022 left_nritems = btrfs_header_nritems(&left->header);
1023 if (left_nritems == 0) {
1024 btrfs_block_release(root, right_buf);
1027 for (i = left_nritems - 1; i >= 1; i--) {
1028 item = left->items + i;
1029 if (path->slots[0] == i)
1030 push_space += data_size + sizeof(*item);
1031 if (btrfs_item_size(item) + sizeof(*item) + push_space >
1035 push_space += btrfs_item_size(item) + sizeof(*item);
1037 if (push_items == 0) {
1038 btrfs_block_release(root, right_buf);
1041 if (push_items == left_nritems)
1043 right_nritems = btrfs_header_nritems(&right->header);
1044 /* push left to right */
1045 push_space = btrfs_item_end(left->items + left_nritems - push_items);
1046 push_space -= leaf_data_end(root, left);
1047 /* make room in the right data area */
1048 btrfs_memmove(root, right, btrfs_leaf_data(right) +
1049 leaf_data_end(root, right) - push_space,
1050 btrfs_leaf_data(right) +
1051 leaf_data_end(root, right), BTRFS_LEAF_DATA_SIZE(root) -
1052 leaf_data_end(root, right));
1053 /* copy from the left data area */
1054 btrfs_memcpy(root, right, btrfs_leaf_data(right) +
1055 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1056 btrfs_leaf_data(left) + leaf_data_end(root, left),
1058 btrfs_memmove(root, right, right->items + push_items, right->items,
1059 right_nritems * sizeof(struct btrfs_item));
1060 /* copy the items from left to right */
1061 btrfs_memcpy(root, right, right->items, left->items +
1062 left_nritems - push_items,
1063 push_items * sizeof(struct btrfs_item));
1065 /* update the item pointers */
1066 right_nritems += push_items;
1067 btrfs_set_header_nritems(&right->header, right_nritems);
1068 push_space = BTRFS_LEAF_DATA_SIZE(root);
1069 for (i = 0; i < right_nritems; i++) {
1070 btrfs_set_item_offset(right->items + i, push_space -
1071 btrfs_item_size(right->items + i));
1072 push_space = btrfs_item_offset(right->items + i);
1074 left_nritems -= push_items;
1075 btrfs_set_header_nritems(&left->header, left_nritems);
1077 btrfs_mark_buffer_dirty(left_buf);
1078 btrfs_mark_buffer_dirty(right_buf);
1080 btrfs_memcpy(root, upper_node, &upper_node->ptrs[slot + 1].key,
1081 &right->items[0].key, sizeof(struct btrfs_disk_key));
1082 btrfs_mark_buffer_dirty(upper);
1084 /* then fixup the leaf pointer in the path */
1085 if (path->slots[0] >= left_nritems) {
1086 path->slots[0] -= left_nritems;
1087 btrfs_block_release(root, path->nodes[0]);
1088 path->nodes[0] = right_buf;
1089 path->slots[1] += 1;
1091 btrfs_block_release(root, right_buf);
1096 * push some data in the path leaf to the left, trying to free up at
1097 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1099 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1100 *root, struct btrfs_path *path, int data_size)
1102 struct buffer_head *right_buf = path->nodes[0];
1103 struct btrfs_leaf *right = btrfs_buffer_leaf(right_buf);
1104 struct buffer_head *t;
1105 struct btrfs_leaf *left;
1111 struct btrfs_item *item;
1112 u32 old_left_nritems;
1116 slot = path->slots[1];
1120 if (!path->nodes[1]) {
1123 t = read_tree_block(root,
1124 btrfs_node_blockptr(btrfs_buffer_node(path->nodes[1]), slot - 1));
1125 left = btrfs_buffer_leaf(t);
1126 free_space = btrfs_leaf_free_space(root, left);
1127 if (free_space < data_size + sizeof(struct btrfs_item)) {
1128 btrfs_block_release(root, t);
1132 /* cow and double check */
1133 btrfs_cow_block(trans, root, t, path->nodes[1], slot - 1, &t);
1134 left = btrfs_buffer_leaf(t);
1135 free_space = btrfs_leaf_free_space(root, left);
1136 if (free_space < data_size + sizeof(struct btrfs_item)) {
1137 btrfs_block_release(root, t);
1141 if (btrfs_header_nritems(&right->header) == 0) {
1142 btrfs_block_release(root, t);
1146 for (i = 0; i < btrfs_header_nritems(&right->header) - 1; i++) {
1147 item = right->items + i;
1148 if (path->slots[0] == i)
1149 push_space += data_size + sizeof(*item);
1150 if (btrfs_item_size(item) + sizeof(*item) + push_space >
1154 push_space += btrfs_item_size(item) + sizeof(*item);
1156 if (push_items == 0) {
1157 btrfs_block_release(root, t);
1160 if (push_items == btrfs_header_nritems(&right->header))
1162 /* push data from right to left */
1163 btrfs_memcpy(root, left, left->items +
1164 btrfs_header_nritems(&left->header),
1165 right->items, push_items * sizeof(struct btrfs_item));
1166 push_space = BTRFS_LEAF_DATA_SIZE(root) -
1167 btrfs_item_offset(right->items + push_items -1);
1168 btrfs_memcpy(root, left, btrfs_leaf_data(left) +
1169 leaf_data_end(root, left) - push_space,
1170 btrfs_leaf_data(right) +
1171 btrfs_item_offset(right->items + push_items - 1),
1173 old_left_nritems = btrfs_header_nritems(&left->header);
1174 BUG_ON(old_left_nritems < 0);
1176 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1177 u32 ioff = btrfs_item_offset(left->items + i);
1178 btrfs_set_item_offset(left->items + i, ioff -
1179 (BTRFS_LEAF_DATA_SIZE(root) -
1180 btrfs_item_offset(left->items +
1181 old_left_nritems - 1)));
1183 btrfs_set_header_nritems(&left->header, old_left_nritems + push_items);
1185 /* fixup right node */
1186 push_space = btrfs_item_offset(right->items + push_items - 1) -
1187 leaf_data_end(root, right);
1188 btrfs_memmove(root, right, btrfs_leaf_data(right) +
1189 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1190 btrfs_leaf_data(right) +
1191 leaf_data_end(root, right), push_space);
1192 btrfs_memmove(root, right, right->items, right->items + push_items,
1193 (btrfs_header_nritems(&right->header) - push_items) *
1194 sizeof(struct btrfs_item));
1195 btrfs_set_header_nritems(&right->header,
1196 btrfs_header_nritems(&right->header) -
1198 push_space = BTRFS_LEAF_DATA_SIZE(root);
1200 for (i = 0; i < btrfs_header_nritems(&right->header); i++) {
1201 btrfs_set_item_offset(right->items + i, push_space -
1202 btrfs_item_size(right->items + i));
1203 push_space = btrfs_item_offset(right->items + i);
1206 btrfs_mark_buffer_dirty(t);
1207 btrfs_mark_buffer_dirty(right_buf);
1208 wret = fixup_low_keys(trans, root, path, &right->items[0].key, 1);
1212 /* then fixup the leaf pointer in the path */
1213 if (path->slots[0] < push_items) {
1214 path->slots[0] += old_left_nritems;
1215 btrfs_block_release(root, path->nodes[0]);
1217 path->slots[1] -= 1;
1219 btrfs_block_release(root, t);
1220 path->slots[0] -= push_items;
1222 BUG_ON(path->slots[0] < 0);
1227 * split the path's leaf in two, making sure there is at least data_size
1228 * available for the resulting leaf level of the path.
1230 * returns 0 if all went well and < 0 on failure.
1232 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
1233 *root, struct btrfs_key *ins_key,
1234 struct btrfs_path *path, int data_size)
1236 struct buffer_head *l_buf;
1237 struct btrfs_leaf *l;
1241 struct btrfs_leaf *right;
1242 struct buffer_head *right_buffer;
1243 int space_needed = data_size + sizeof(struct btrfs_item);
1249 int double_split = 0;
1250 struct btrfs_disk_key disk_key;
1252 /* first try to make some room by pushing left and right */
1253 wret = push_leaf_left(trans, root, path, data_size);
1257 wret = push_leaf_right(trans, root, path, data_size);
1261 l_buf = path->nodes[0];
1262 l = btrfs_buffer_leaf(l_buf);
1264 /* did the pushes work? */
1265 if (btrfs_leaf_free_space(root, l) >=
1266 sizeof(struct btrfs_item) + data_size)
1269 if (!path->nodes[1]) {
1270 ret = insert_new_root(trans, root, path, 1);
1274 slot = path->slots[0];
1275 nritems = btrfs_header_nritems(&l->header);
1276 mid = (nritems + 1)/ 2;
1277 right_buffer = btrfs_alloc_free_block(trans, root);
1278 BUG_ON(!right_buffer);
1279 right = btrfs_buffer_leaf(right_buffer);
1280 memset(&right->header, 0, sizeof(right->header));
1281 btrfs_set_header_blocknr(&right->header, bh_blocknr(right_buffer));
1282 btrfs_set_header_generation(&right->header, trans->transid);
1283 btrfs_set_header_level(&right->header, 0);
1284 memcpy(right->header.fsid, root->fs_info->disk_super->fsid,
1285 sizeof(right->header.fsid));
1288 leaf_space_used(l, mid, nritems - mid) + space_needed >
1289 BTRFS_LEAF_DATA_SIZE(root)) {
1290 if (slot >= nritems) {
1291 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1292 btrfs_set_header_nritems(&right->header, 0);
1293 wret = insert_ptr(trans, root, path,
1295 bh_blocknr(right_buffer),
1296 path->slots[1] + 1, 1);
1299 btrfs_block_release(root, path->nodes[0]);
1300 path->nodes[0] = right_buffer;
1302 path->slots[1] += 1;
1309 if (leaf_space_used(l, 0, mid + 1) + space_needed >
1310 BTRFS_LEAF_DATA_SIZE(root)) {
1312 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1313 btrfs_set_header_nritems(&right->header, 0);
1314 wret = insert_ptr(trans, root, path,
1316 bh_blocknr(right_buffer),
1317 path->slots[1] - 1, 1);
1320 btrfs_block_release(root, path->nodes[0]);
1321 path->nodes[0] = right_buffer;
1323 path->slots[1] -= 1;
1324 if (path->slots[1] == 0) {
1325 wret = fixup_low_keys(trans, root,
1326 path, &disk_key, 1);
1336 btrfs_set_header_nritems(&right->header, nritems - mid);
1337 data_copy_size = btrfs_item_end(l->items + mid) -
1338 leaf_data_end(root, l);
1339 btrfs_memcpy(root, right, right->items, l->items + mid,
1340 (nritems - mid) * sizeof(struct btrfs_item));
1341 btrfs_memcpy(root, right,
1342 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
1343 data_copy_size, btrfs_leaf_data(l) +
1344 leaf_data_end(root, l), data_copy_size);
1345 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
1346 btrfs_item_end(l->items + mid);
1348 for (i = 0; i < btrfs_header_nritems(&right->header); i++) {
1349 u32 ioff = btrfs_item_offset(right->items + i);
1350 btrfs_set_item_offset(right->items + i, ioff + rt_data_off);
1353 btrfs_set_header_nritems(&l->header, mid);
1355 wret = insert_ptr(trans, root, path, &right->items[0].key,
1356 bh_blocknr(right_buffer), path->slots[1] + 1, 1);
1359 btrfs_mark_buffer_dirty(right_buffer);
1360 btrfs_mark_buffer_dirty(l_buf);
1361 BUG_ON(path->slots[0] != slot);
1363 btrfs_block_release(root, path->nodes[0]);
1364 path->nodes[0] = right_buffer;
1365 path->slots[0] -= mid;
1366 path->slots[1] += 1;
1368 btrfs_block_release(root, right_buffer);
1369 BUG_ON(path->slots[0] < 0);
1373 right_buffer = btrfs_alloc_free_block(trans, root);
1374 BUG_ON(!right_buffer);
1375 right = btrfs_buffer_leaf(right_buffer);
1376 memset(&right->header, 0, sizeof(right->header));
1377 btrfs_set_header_blocknr(&right->header, bh_blocknr(right_buffer));
1378 btrfs_set_header_generation(&right->header, trans->transid);
1379 btrfs_set_header_level(&right->header, 0);
1380 memcpy(right->header.fsid, root->fs_info->disk_super->fsid,
1381 sizeof(right->header.fsid));
1382 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1383 btrfs_set_header_nritems(&right->header, 0);
1384 wret = insert_ptr(trans, root, path,
1386 bh_blocknr(right_buffer),
1390 if (path->slots[1] == 0) {
1391 wret = fixup_low_keys(trans, root, path, &disk_key, 1);
1395 btrfs_block_release(root, path->nodes[0]);
1396 path->nodes[0] = right_buffer;
1398 check_node(root, path, 1);
1399 check_leaf(root, path, 0);
1403 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
1404 struct btrfs_root *root,
1405 struct btrfs_path *path,
1411 struct btrfs_leaf *leaf;
1412 struct buffer_head *leaf_buf;
1414 unsigned int data_end;
1415 unsigned int old_data_start;
1416 unsigned int old_size;
1417 unsigned int size_diff;
1420 slot_orig = path->slots[0];
1421 leaf_buf = path->nodes[0];
1422 leaf = btrfs_buffer_leaf(leaf_buf);
1424 nritems = btrfs_header_nritems(&leaf->header);
1425 data_end = leaf_data_end(root, leaf);
1427 slot = path->slots[0];
1428 old_data_start = btrfs_item_offset(leaf->items + slot);
1429 old_size = btrfs_item_size(leaf->items + slot);
1430 BUG_ON(old_size <= new_size);
1431 size_diff = old_size - new_size;
1434 BUG_ON(slot >= nritems);
1437 * item0..itemN ... dataN.offset..dataN.size .. data0.size
1439 /* first correct the data pointers */
1440 for (i = slot; i < nritems; i++) {
1441 u32 ioff = btrfs_item_offset(leaf->items + i);
1442 btrfs_set_item_offset(leaf->items + i,
1445 /* shift the data */
1446 btrfs_memmove(root, leaf, btrfs_leaf_data(leaf) +
1447 data_end + size_diff, btrfs_leaf_data(leaf) +
1448 data_end, old_data_start + new_size - data_end);
1449 btrfs_set_item_size(leaf->items + slot, new_size);
1450 btrfs_mark_buffer_dirty(leaf_buf);
1453 if (btrfs_leaf_free_space(root, leaf) < 0)
1455 check_leaf(root, path, 0);
1459 int btrfs_extend_item(struct btrfs_trans_handle *trans, struct btrfs_root
1460 *root, struct btrfs_path *path, u32 data_size)
1465 struct btrfs_leaf *leaf;
1466 struct buffer_head *leaf_buf;
1468 unsigned int data_end;
1469 unsigned int old_data;
1470 unsigned int old_size;
1473 slot_orig = path->slots[0];
1474 leaf_buf = path->nodes[0];
1475 leaf = btrfs_buffer_leaf(leaf_buf);
1477 nritems = btrfs_header_nritems(&leaf->header);
1478 data_end = leaf_data_end(root, leaf);
1480 if (btrfs_leaf_free_space(root, leaf) < data_size)
1482 slot = path->slots[0];
1483 old_data = btrfs_item_end(leaf->items + slot);
1486 BUG_ON(slot >= nritems);
1489 * item0..itemN ... dataN.offset..dataN.size .. data0.size
1491 /* first correct the data pointers */
1492 for (i = slot; i < nritems; i++) {
1493 u32 ioff = btrfs_item_offset(leaf->items + i);
1494 btrfs_set_item_offset(leaf->items + i,
1497 /* shift the data */
1498 btrfs_memmove(root, leaf, btrfs_leaf_data(leaf) +
1499 data_end - data_size, btrfs_leaf_data(leaf) +
1500 data_end, old_data - data_end);
1501 data_end = old_data;
1502 old_size = btrfs_item_size(leaf->items + slot);
1503 btrfs_set_item_size(leaf->items + slot, old_size + data_size);
1504 btrfs_mark_buffer_dirty(leaf_buf);
1507 if (btrfs_leaf_free_space(root, leaf) < 0)
1509 check_leaf(root, path, 0);
1514 * Given a key and some data, insert an item into the tree.
1515 * This does all the path init required, making room in the tree if needed.
1517 int btrfs_insert_empty_item(struct btrfs_trans_handle *trans, struct btrfs_root
1518 *root, struct btrfs_path *path, struct btrfs_key
1519 *cpu_key, u32 data_size)
1524 struct btrfs_leaf *leaf;
1525 struct buffer_head *leaf_buf;
1527 unsigned int data_end;
1528 struct btrfs_disk_key disk_key;
1530 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
1532 /* create a root if there isn't one */
1535 ret = btrfs_search_slot(trans, root, cpu_key, path, data_size, 1);
1542 slot_orig = path->slots[0];
1543 leaf_buf = path->nodes[0];
1544 leaf = btrfs_buffer_leaf(leaf_buf);
1546 nritems = btrfs_header_nritems(&leaf->header);
1547 data_end = leaf_data_end(root, leaf);
1549 if (btrfs_leaf_free_space(root, leaf) <
1550 sizeof(struct btrfs_item) + data_size) {
1553 slot = path->slots[0];
1555 if (slot != nritems) {
1557 unsigned int old_data = btrfs_item_end(leaf->items + slot);
1560 * item0..itemN ... dataN.offset..dataN.size .. data0.size
1562 /* first correct the data pointers */
1563 for (i = slot; i < nritems; i++) {
1564 u32 ioff = btrfs_item_offset(leaf->items + i);
1565 btrfs_set_item_offset(leaf->items + i,
1569 /* shift the items */
1570 btrfs_memmove(root, leaf, leaf->items + slot + 1,
1572 (nritems - slot) * sizeof(struct btrfs_item));
1574 /* shift the data */
1575 btrfs_memmove(root, leaf, btrfs_leaf_data(leaf) +
1576 data_end - data_size, btrfs_leaf_data(leaf) +
1577 data_end, old_data - data_end);
1578 data_end = old_data;
1580 /* setup the item for the new data */
1581 btrfs_memcpy(root, leaf, &leaf->items[slot].key, &disk_key,
1582 sizeof(struct btrfs_disk_key));
1583 btrfs_set_item_offset(leaf->items + slot, data_end - data_size);
1584 btrfs_set_item_size(leaf->items + slot, data_size);
1585 btrfs_set_header_nritems(&leaf->header, nritems + 1);
1586 btrfs_mark_buffer_dirty(leaf_buf);
1590 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
1592 if (btrfs_leaf_free_space(root, leaf) < 0)
1594 check_leaf(root, path, 0);
1600 * Given a key and some data, insert an item into the tree.
1601 * This does all the path init required, making room in the tree if needed.
1603 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
1604 *root, struct btrfs_key *cpu_key, void *data, u32
1608 struct btrfs_path *path;
1611 path = btrfs_alloc_path();
1613 btrfs_init_path(path);
1614 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
1616 ptr = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
1617 path->slots[0], u8);
1618 btrfs_memcpy(root, path->nodes[0]->b_data,
1619 ptr, data, data_size);
1620 btrfs_mark_buffer_dirty(path->nodes[0]);
1622 btrfs_release_path(root, path);
1623 btrfs_free_path(path);
1628 * delete the pointer from a given node.
1630 * If the delete empties a node, the node is removed from the tree,
1631 * continuing all the way the root if required. The root is converted into
1632 * a leaf if all the nodes are emptied.
1634 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1635 struct btrfs_path *path, int level, int slot)
1637 struct btrfs_node *node;
1638 struct buffer_head *parent = path->nodes[level];
1643 node = btrfs_buffer_node(parent);
1644 nritems = btrfs_header_nritems(&node->header);
1645 if (slot != nritems -1) {
1646 btrfs_memmove(root, node, node->ptrs + slot,
1647 node->ptrs + slot + 1,
1648 sizeof(struct btrfs_key_ptr) *
1649 (nritems - slot - 1));
1652 btrfs_set_header_nritems(&node->header, nritems);
1653 if (nritems == 0 && parent == root->node) {
1654 struct btrfs_header *header = btrfs_buffer_header(root->node);
1655 BUG_ON(btrfs_header_level(header) != 1);
1656 /* just turn the root into a leaf and break */
1657 btrfs_set_header_level(header, 0);
1658 } else if (slot == 0) {
1659 wret = fixup_low_keys(trans, root, path, &node->ptrs[0].key,
1664 btrfs_mark_buffer_dirty(parent);
1669 * delete the item at the leaf level in path. If that empties
1670 * the leaf, remove it from the tree
1672 int btrfs_del_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1673 struct btrfs_path *path)
1676 struct btrfs_leaf *leaf;
1677 struct buffer_head *leaf_buf;
1684 leaf_buf = path->nodes[0];
1685 leaf = btrfs_buffer_leaf(leaf_buf);
1686 slot = path->slots[0];
1687 doff = btrfs_item_offset(leaf->items + slot);
1688 dsize = btrfs_item_size(leaf->items + slot);
1689 nritems = btrfs_header_nritems(&leaf->header);
1691 if (slot != nritems - 1) {
1693 int data_end = leaf_data_end(root, leaf);
1694 btrfs_memmove(root, leaf, btrfs_leaf_data(leaf) +
1696 btrfs_leaf_data(leaf) + data_end,
1698 for (i = slot + 1; i < nritems; i++) {
1699 u32 ioff = btrfs_item_offset(leaf->items + i);
1700 btrfs_set_item_offset(leaf->items + i, ioff + dsize);
1702 btrfs_memmove(root, leaf, leaf->items + slot,
1703 leaf->items + slot + 1,
1704 sizeof(struct btrfs_item) *
1705 (nritems - slot - 1));
1707 btrfs_set_header_nritems(&leaf->header, nritems - 1);
1709 /* delete the leaf if we've emptied it */
1711 if (leaf_buf == root->node) {
1712 btrfs_set_header_level(&leaf->header, 0);
1714 clean_tree_block(trans, root, leaf_buf);
1715 wait_on_buffer(leaf_buf);
1716 wret = del_ptr(trans, root, path, 1, path->slots[1]);
1719 wret = btrfs_free_extent(trans, root,
1720 bh_blocknr(leaf_buf), 1, 1);
1725 int used = leaf_space_used(leaf, 0, nritems);
1727 wret = fixup_low_keys(trans, root, path,
1728 &leaf->items[0].key, 1);
1733 /* delete the leaf if it is mostly empty */
1734 if (used < BTRFS_LEAF_DATA_SIZE(root) / 3) {
1735 /* push_leaf_left fixes the path.
1736 * make sure the path still points to our leaf
1737 * for possible call to del_ptr below
1739 slot = path->slots[1];
1741 wret = push_leaf_left(trans, root, path, 1);
1744 if (path->nodes[0] == leaf_buf &&
1745 btrfs_header_nritems(&leaf->header)) {
1746 wret = push_leaf_right(trans, root, path, 1);
1750 if (btrfs_header_nritems(&leaf->header) == 0) {
1751 u64 blocknr = bh_blocknr(leaf_buf);
1752 clean_tree_block(trans, root, leaf_buf);
1753 wait_on_buffer(leaf_buf);
1754 wret = del_ptr(trans, root, path, 1, slot);
1757 btrfs_block_release(root, leaf_buf);
1758 wret = btrfs_free_extent(trans, root, blocknr,
1763 btrfs_mark_buffer_dirty(leaf_buf);
1764 btrfs_block_release(root, leaf_buf);
1767 btrfs_mark_buffer_dirty(leaf_buf);
1774 * walk up the tree as far as required to find the next leaf.
1775 * returns 0 if it found something or 1 if there are no greater leaves.
1776 * returns < 0 on io errors.
1778 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
1783 struct buffer_head *c;
1784 struct btrfs_node *c_node;
1785 struct buffer_head *next = NULL;
1787 while(level < BTRFS_MAX_LEVEL) {
1788 if (!path->nodes[level])
1790 slot = path->slots[level] + 1;
1791 c = path->nodes[level];
1792 c_node = btrfs_buffer_node(c);
1793 if (slot >= btrfs_header_nritems(&c_node->header)) {
1797 blocknr = btrfs_node_blockptr(c_node, slot);
1799 btrfs_block_release(root, next);
1800 next = read_tree_block(root, blocknr);
1803 path->slots[level] = slot;
1806 c = path->nodes[level];
1807 btrfs_block_release(root, c);
1808 path->nodes[level] = next;
1809 path->slots[level] = 0;
1812 next = read_tree_block(root,
1813 btrfs_node_blockptr(btrfs_buffer_node(next), 0));