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, buf->b_blocknr);
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_set_header_owner(&cow_node->header, root->root_key.objectid);
72 btrfs_inc_ref(trans, root, buf);
73 if (buf == root->node) {
76 if (buf != root->commit_root) {
77 btrfs_free_extent(trans, root, bh_blocknr(buf), 1, 1);
79 btrfs_block_release(root, buf);
81 btrfs_set_node_blockptr(btrfs_buffer_node(parent), parent_slot,
83 btrfs_mark_buffer_dirty(parent);
84 btrfs_free_extent(trans, root, bh_blocknr(buf), 1, 1);
86 btrfs_block_release(root, buf);
87 mark_buffer_dirty(cow);
93 * The leaf data grows from end-to-front in the node.
94 * this returns the address of the start of the last item,
95 * which is the stop of the leaf data stack
97 static inline unsigned int leaf_data_end(struct btrfs_root *root,
98 struct btrfs_leaf *leaf)
100 u32 nr = btrfs_header_nritems(&leaf->header);
102 return BTRFS_LEAF_DATA_SIZE(root);
103 return btrfs_item_offset(leaf->items + nr - 1);
107 * compare two keys in a memcmp fashion
109 static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
113 btrfs_disk_key_to_cpu(&k1, disk);
115 if (k1.objectid > k2->objectid)
117 if (k1.objectid < k2->objectid)
119 if (k1.flags > k2->flags)
121 if (k1.flags < k2->flags)
123 if (k1.offset > k2->offset)
125 if (k1.offset < k2->offset)
130 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]);
137 struct btrfs_key cpukey;
138 u32 nritems = btrfs_header_nritems(&node->header);
140 if (path->nodes[level + 1])
141 parent = btrfs_buffer_node(path->nodes[level + 1]);
142 parent_slot = path->slots[level + 1];
143 slot = path->slots[level];
144 BUG_ON(nritems == 0);
146 struct btrfs_disk_key *parent_key;
147 parent_key = &parent->ptrs[parent_slot].key;
148 BUG_ON(memcmp(parent_key, &node->ptrs[0].key,
149 sizeof(struct btrfs_disk_key)));
150 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
151 btrfs_header_blocknr(&node->header));
153 BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
155 btrfs_disk_key_to_cpu(&cpukey, &node->ptrs[slot - 1].key);
156 BUG_ON(comp_keys(&node->ptrs[slot].key, &cpukey) <= 0);
158 if (slot < nritems - 1) {
159 btrfs_disk_key_to_cpu(&cpukey, &node->ptrs[slot + 1].key);
160 BUG_ON(comp_keys(&node->ptrs[slot].key, &cpukey) >= 0);
165 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
168 struct btrfs_leaf *leaf = btrfs_buffer_leaf(path->nodes[level]);
169 struct btrfs_node *parent = NULL;
171 int slot = path->slots[0];
172 struct btrfs_key cpukey;
174 u32 nritems = btrfs_header_nritems(&leaf->header);
176 if (path->nodes[level + 1])
177 parent = btrfs_buffer_node(path->nodes[level + 1]);
178 parent_slot = path->slots[level + 1];
179 BUG_ON(btrfs_leaf_free_space(root, leaf) < 0);
185 struct btrfs_disk_key *parent_key;
186 parent_key = &parent->ptrs[parent_slot].key;
187 BUG_ON(memcmp(parent_key, &leaf->items[0].key,
188 sizeof(struct btrfs_disk_key)));
189 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
190 btrfs_header_blocknr(&leaf->header));
193 btrfs_disk_key_to_cpu(&cpukey, &leaf->items[slot - 1].key);
194 BUG_ON(comp_keys(&leaf->items[slot].key, &cpukey) <= 0);
195 BUG_ON(btrfs_item_offset(leaf->items + slot - 1) !=
196 btrfs_item_end(leaf->items + slot));
198 if (slot < nritems - 1) {
199 btrfs_disk_key_to_cpu(&cpukey, &leaf->items[slot + 1].key);
200 BUG_ON(comp_keys(&leaf->items[slot].key, &cpukey) >= 0);
201 BUG_ON(btrfs_item_offset(leaf->items + slot) !=
202 btrfs_item_end(leaf->items + slot + 1));
204 BUG_ON(btrfs_item_offset(leaf->items) +
205 btrfs_item_size(leaf->items) != BTRFS_LEAF_DATA_SIZE(root));
209 static int check_block(struct btrfs_root *root, struct btrfs_path *path,
212 struct btrfs_node *node = btrfs_buffer_node(path->nodes[level]);
213 if (memcmp(node->header.fsid, root->fs_info->disk_super->fsid,
214 sizeof(node->header.fsid)))
217 return check_leaf(root, path, level);
218 return check_node(root, path, level);
222 * search for key in the array p. items p are item_size apart
223 * and there are 'max' items in p
224 * the slot in the array is returned via slot, and it points to
225 * the place where you would insert key if it is not found in
228 * slot may point to max if the key is bigger than all of the keys
230 static int generic_bin_search(char *p, int item_size, struct btrfs_key *key,
237 struct btrfs_disk_key *tmp;
240 mid = (low + high) / 2;
241 tmp = (struct btrfs_disk_key *)(p + mid * item_size);
242 ret = comp_keys(tmp, key);
258 * simple bin_search frontend that does the right thing for
261 static int bin_search(struct btrfs_node *c, struct btrfs_key *key, int *slot)
263 if (btrfs_is_leaf(c)) {
264 struct btrfs_leaf *l = (struct btrfs_leaf *)c;
265 return generic_bin_search((void *)l->items,
266 sizeof(struct btrfs_item),
267 key, btrfs_header_nritems(&c->header),
270 return generic_bin_search((void *)c->ptrs,
271 sizeof(struct btrfs_key_ptr),
272 key, btrfs_header_nritems(&c->header),
278 static struct buffer_head *read_node_slot(struct btrfs_root *root,
279 struct buffer_head *parent_buf,
282 struct btrfs_node *node = btrfs_buffer_node(parent_buf);
285 if (slot >= btrfs_header_nritems(&node->header))
287 return read_tree_block(root, btrfs_node_blockptr(node, slot));
290 static int balance_level(struct btrfs_trans_handle *trans, struct btrfs_root
291 *root, struct btrfs_path *path, int level)
293 struct buffer_head *right_buf;
294 struct buffer_head *mid_buf;
295 struct buffer_head *left_buf;
296 struct buffer_head *parent_buf = NULL;
297 struct btrfs_node *right = NULL;
298 struct btrfs_node *mid;
299 struct btrfs_node *left = NULL;
300 struct btrfs_node *parent = NULL;
304 int orig_slot = path->slots[level];
310 mid_buf = path->nodes[level];
311 mid = btrfs_buffer_node(mid_buf);
312 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
314 if (level < BTRFS_MAX_LEVEL - 1)
315 parent_buf = path->nodes[level + 1];
316 pslot = path->slots[level + 1];
319 * deal with the case where there is only one pointer in the root
320 * by promoting the node below to a root
323 struct buffer_head *child;
324 u64 blocknr = bh_blocknr(mid_buf);
326 if (btrfs_header_nritems(&mid->header) != 1)
329 /* promote the child to a root */
330 child = read_node_slot(root, mid_buf, 0);
333 path->nodes[level] = NULL;
334 clean_tree_block(trans, root, mid_buf);
335 wait_on_buffer(mid_buf);
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 return btrfs_free_extent(trans, root, blocknr, 1, 1);
342 parent = btrfs_buffer_node(parent_buf);
344 if (btrfs_header_nritems(&mid->header) >
345 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
348 left_buf = read_node_slot(root, parent_buf, pslot - 1);
349 right_buf = read_node_slot(root, parent_buf, pslot + 1);
351 /* first, try to make some room in the middle buffer */
353 btrfs_cow_block(trans, root, left_buf, parent_buf, pslot - 1,
355 left = btrfs_buffer_node(left_buf);
356 orig_slot += btrfs_header_nritems(&left->header);
357 wret = push_node_left(trans, root, left_buf, mid_buf);
363 * then try to empty the right most buffer into the middle
366 btrfs_cow_block(trans, root, right_buf, parent_buf, pslot + 1,
368 right = btrfs_buffer_node(right_buf);
369 wret = push_node_left(trans, root, mid_buf, right_buf);
372 if (btrfs_header_nritems(&right->header) == 0) {
373 u64 blocknr = bh_blocknr(right_buf);
374 clean_tree_block(trans, root, right_buf);
375 wait_on_buffer(right_buf);
376 btrfs_block_release(root, right_buf);
379 wret = del_ptr(trans, root, path, level + 1, pslot +
383 wret = btrfs_free_extent(trans, root, blocknr, 1, 1);
387 btrfs_memcpy(root, parent,
388 &parent->ptrs[pslot + 1].key,
390 sizeof(struct btrfs_disk_key));
391 btrfs_mark_buffer_dirty(parent_buf);
394 if (btrfs_header_nritems(&mid->header) == 1) {
396 * we're not allowed to leave a node with one item in the
397 * tree during a delete. A deletion from lower in the tree
398 * could try to delete the only pointer in this node.
399 * So, pull some keys from the left.
400 * There has to be a left pointer at this point because
401 * otherwise we would have pulled some pointers from the
405 wret = balance_node_right(trans, root, mid_buf, left_buf);
410 if (btrfs_header_nritems(&mid->header) == 0) {
411 /* we've managed to empty the middle node, drop it */
412 u64 blocknr = bh_blocknr(mid_buf);
413 clean_tree_block(trans, root, mid_buf);
414 wait_on_buffer(mid_buf);
415 btrfs_block_release(root, mid_buf);
418 wret = del_ptr(trans, root, path, level + 1, pslot);
421 wret = btrfs_free_extent(trans, root, blocknr, 1, 1);
425 /* update the parent key to reflect our changes */
426 btrfs_memcpy(root, parent,
427 &parent->ptrs[pslot].key, &mid->ptrs[0].key,
428 sizeof(struct btrfs_disk_key));
429 btrfs_mark_buffer_dirty(parent_buf);
432 /* update the path */
434 if (btrfs_header_nritems(&left->header) > orig_slot) {
436 path->nodes[level] = left_buf;
437 path->slots[level + 1] -= 1;
438 path->slots[level] = orig_slot;
440 btrfs_block_release(root, mid_buf);
442 orig_slot -= btrfs_header_nritems(&left->header);
443 path->slots[level] = orig_slot;
446 /* double check we haven't messed things up */
447 check_block(root, path, level);
449 btrfs_node_blockptr(btrfs_buffer_node(path->nodes[level]),
454 btrfs_block_release(root, right_buf);
456 btrfs_block_release(root, left_buf);
460 /* returns zero if the push worked, non-zero otherwise */
461 static int push_nodes_for_insert(struct btrfs_trans_handle *trans,
462 struct btrfs_root *root,
463 struct btrfs_path *path, int level)
465 struct buffer_head *right_buf;
466 struct buffer_head *mid_buf;
467 struct buffer_head *left_buf;
468 struct buffer_head *parent_buf = NULL;
469 struct btrfs_node *right = NULL;
470 struct btrfs_node *mid;
471 struct btrfs_node *left = NULL;
472 struct btrfs_node *parent = NULL;
476 int orig_slot = path->slots[level];
482 mid_buf = path->nodes[level];
483 mid = btrfs_buffer_node(mid_buf);
484 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
486 if (level < BTRFS_MAX_LEVEL - 1)
487 parent_buf = path->nodes[level + 1];
488 pslot = path->slots[level + 1];
492 parent = btrfs_buffer_node(parent_buf);
494 left_buf = read_node_slot(root, parent_buf, pslot - 1);
496 /* first, try to make some room in the middle buffer */
499 left = btrfs_buffer_node(left_buf);
500 left_nr = btrfs_header_nritems(&left->header);
501 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
504 btrfs_cow_block(trans, root, left_buf, parent_buf,
505 pslot - 1, &left_buf);
506 left = btrfs_buffer_node(left_buf);
507 wret = push_node_left(trans, root, left_buf, mid_buf);
512 orig_slot += left_nr;
513 btrfs_memcpy(root, parent,
514 &parent->ptrs[pslot].key,
516 sizeof(struct btrfs_disk_key));
517 btrfs_mark_buffer_dirty(parent_buf);
518 if (btrfs_header_nritems(&left->header) > orig_slot) {
519 path->nodes[level] = left_buf;
520 path->slots[level + 1] -= 1;
521 path->slots[level] = orig_slot;
522 btrfs_block_release(root, mid_buf);
525 btrfs_header_nritems(&left->header);
526 path->slots[level] = orig_slot;
527 btrfs_block_release(root, left_buf);
529 check_node(root, path, level);
532 btrfs_block_release(root, left_buf);
534 right_buf = read_node_slot(root, parent_buf, pslot + 1);
537 * then try to empty the right most buffer into the middle
541 right = btrfs_buffer_node(right_buf);
542 right_nr = btrfs_header_nritems(&right->header);
543 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
546 btrfs_cow_block(trans, root, right_buf,
547 parent_buf, pslot + 1, &right_buf);
548 right = btrfs_buffer_node(right_buf);
549 wret = balance_node_right(trans, root,
555 btrfs_memcpy(root, parent,
556 &parent->ptrs[pslot + 1].key,
558 sizeof(struct btrfs_disk_key));
559 btrfs_mark_buffer_dirty(parent_buf);
560 if (btrfs_header_nritems(&mid->header) <= orig_slot) {
561 path->nodes[level] = right_buf;
562 path->slots[level + 1] += 1;
563 path->slots[level] = orig_slot -
564 btrfs_header_nritems(&mid->header);
565 btrfs_block_release(root, mid_buf);
567 btrfs_block_release(root, right_buf);
569 check_node(root, path, level);
572 btrfs_block_release(root, right_buf);
574 check_node(root, path, level);
579 * look for key in the tree. path is filled in with nodes along the way
580 * if key is found, we return zero and you can find the item in the leaf
581 * level of the path (level 0)
583 * If the key isn't found, the path points to the slot where it should
584 * be inserted, and 1 is returned. If there are other errors during the
585 * search a negative error number is returned.
587 * if ins_len > 0, nodes and leaves will be split as we walk down the
588 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
591 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
592 *root, struct btrfs_key *key, struct btrfs_path *p, int
595 struct buffer_head *b;
596 struct buffer_head *cow_buf;
597 struct btrfs_node *c;
602 WARN_ON(p->nodes[0] != NULL);
603 WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
608 c = btrfs_buffer_node(b);
609 level = btrfs_header_level(&c->header);
612 wret = btrfs_cow_block(trans, root, b,
617 c = btrfs_buffer_node(b);
619 BUG_ON(!cow && ins_len);
620 if (level != btrfs_header_level(&c->header))
622 level = btrfs_header_level(&c->header);
624 ret = check_block(root, p, level);
627 ret = bin_search(c, key, &slot);
628 if (!btrfs_is_leaf(c)) {
631 p->slots[level] = slot;
632 if (ins_len > 0 && btrfs_header_nritems(&c->header) >=
633 BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
634 int sret = split_node(trans, root, p, level);
639 c = btrfs_buffer_node(b);
640 slot = p->slots[level];
641 } else if (ins_len < 0) {
642 int sret = balance_level(trans, root, p,
649 c = btrfs_buffer_node(b);
650 slot = p->slots[level];
651 BUG_ON(btrfs_header_nritems(&c->header) == 1);
653 b = read_tree_block(root, btrfs_node_blockptr(c, slot));
655 struct btrfs_leaf *l = (struct btrfs_leaf *)c;
656 p->slots[level] = slot;
657 if (ins_len > 0 && btrfs_leaf_free_space(root, l) <
658 sizeof(struct btrfs_item) + ins_len) {
659 int sret = split_leaf(trans, root, key,
672 * adjust the pointers going up the tree, starting at level
673 * making sure the right key of each node is points to 'key'.
674 * This is used after shifting pointers to the left, so it stops
675 * fixing up pointers when a given leaf/node is not in slot 0 of the
678 * If this fails to write a tree block, it returns -1, but continues
679 * fixing up the blocks in ram so the tree is consistent.
681 static int fixup_low_keys(struct btrfs_trans_handle *trans, struct btrfs_root
682 *root, struct btrfs_path *path, struct btrfs_disk_key
687 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
688 struct btrfs_node *t;
689 int tslot = path->slots[i];
692 t = btrfs_buffer_node(path->nodes[i]);
693 btrfs_memcpy(root, t, &t->ptrs[tslot].key, key, sizeof(*key));
694 btrfs_mark_buffer_dirty(path->nodes[i]);
702 * try to push data from one node into the next node left in the
705 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
706 * error, and > 0 if there was no room in the left hand block.
708 static int push_node_left(struct btrfs_trans_handle *trans, struct btrfs_root
709 *root, struct buffer_head *dst_buf, struct
710 buffer_head *src_buf)
712 struct btrfs_node *src = btrfs_buffer_node(src_buf);
713 struct btrfs_node *dst = btrfs_buffer_node(dst_buf);
719 src_nritems = btrfs_header_nritems(&src->header);
720 dst_nritems = btrfs_header_nritems(&dst->header);
721 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
722 if (push_items <= 0) {
726 if (src_nritems < push_items)
727 push_items = src_nritems;
729 btrfs_memcpy(root, dst, dst->ptrs + dst_nritems, src->ptrs,
730 push_items * sizeof(struct btrfs_key_ptr));
731 if (push_items < src_nritems) {
732 btrfs_memmove(root, src, src->ptrs, src->ptrs + push_items,
733 (src_nritems - push_items) *
734 sizeof(struct btrfs_key_ptr));
736 btrfs_set_header_nritems(&src->header, src_nritems - push_items);
737 btrfs_set_header_nritems(&dst->header, dst_nritems + push_items);
738 btrfs_mark_buffer_dirty(src_buf);
739 btrfs_mark_buffer_dirty(dst_buf);
744 * try to push data from one node into the next node right in the
747 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
748 * error, and > 0 if there was no room in the right hand block.
750 * this will only push up to 1/2 the contents of the left node over
752 static int balance_node_right(struct btrfs_trans_handle *trans, struct
753 btrfs_root *root, struct buffer_head *dst_buf,
754 struct buffer_head *src_buf)
756 struct btrfs_node *src = btrfs_buffer_node(src_buf);
757 struct btrfs_node *dst = btrfs_buffer_node(dst_buf);
764 src_nritems = btrfs_header_nritems(&src->header);
765 dst_nritems = btrfs_header_nritems(&dst->header);
766 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
767 if (push_items <= 0) {
771 max_push = src_nritems / 2 + 1;
772 /* don't try to empty the node */
773 if (max_push > src_nritems)
775 if (max_push < push_items)
776 push_items = max_push;
778 btrfs_memmove(root, dst, dst->ptrs + push_items, dst->ptrs,
779 dst_nritems * sizeof(struct btrfs_key_ptr));
781 btrfs_memcpy(root, dst, dst->ptrs,
782 src->ptrs + src_nritems - push_items,
783 push_items * sizeof(struct btrfs_key_ptr));
785 btrfs_set_header_nritems(&src->header, src_nritems - push_items);
786 btrfs_set_header_nritems(&dst->header, dst_nritems + push_items);
788 btrfs_mark_buffer_dirty(src_buf);
789 btrfs_mark_buffer_dirty(dst_buf);
794 * helper function to insert a new root level in the tree.
795 * A new node is allocated, and a single item is inserted to
796 * point to the existing root
798 * returns zero on success or < 0 on failure.
800 static int insert_new_root(struct btrfs_trans_handle *trans, struct btrfs_root
801 *root, struct btrfs_path *path, int level)
803 struct buffer_head *t;
804 struct btrfs_node *lower;
805 struct btrfs_node *c;
806 struct btrfs_disk_key *lower_key;
808 BUG_ON(path->nodes[level]);
809 BUG_ON(path->nodes[level-1] != root->node);
811 t = btrfs_alloc_free_block(trans, root, root->node->b_blocknr);
812 c = btrfs_buffer_node(t);
813 memset(c, 0, root->blocksize);
814 btrfs_set_header_nritems(&c->header, 1);
815 btrfs_set_header_level(&c->header, level);
816 btrfs_set_header_blocknr(&c->header, bh_blocknr(t));
817 btrfs_set_header_generation(&c->header, trans->transid);
818 btrfs_set_header_owner(&c->header, root->root_key.objectid);
819 lower = btrfs_buffer_node(path->nodes[level-1]);
820 memcpy(c->header.fsid, root->fs_info->disk_super->fsid,
821 sizeof(c->header.fsid));
822 if (btrfs_is_leaf(lower))
823 lower_key = &((struct btrfs_leaf *)lower)->items[0].key;
825 lower_key = &lower->ptrs[0].key;
826 btrfs_memcpy(root, c, &c->ptrs[0].key, lower_key,
827 sizeof(struct btrfs_disk_key));
828 btrfs_set_node_blockptr(c, 0, bh_blocknr(path->nodes[level - 1]));
830 btrfs_mark_buffer_dirty(t);
832 /* the super has an extra ref to root->node */
833 btrfs_block_release(root, root->node);
836 path->nodes[level] = t;
837 path->slots[level] = 0;
842 * worker function to insert a single pointer in a node.
843 * the node should have enough room for the pointer already
845 * slot and level indicate where you want the key to go, and
846 * blocknr is the block the key points to.
848 * returns zero on success and < 0 on any error
850 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
851 *root, struct btrfs_path *path, struct btrfs_disk_key
852 *key, u64 blocknr, int slot, int level)
854 struct btrfs_node *lower;
857 BUG_ON(!path->nodes[level]);
858 lower = btrfs_buffer_node(path->nodes[level]);
859 nritems = btrfs_header_nritems(&lower->header);
862 if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
864 if (slot != nritems) {
865 btrfs_memmove(root, lower, lower->ptrs + slot + 1,
867 (nritems - slot) * sizeof(struct btrfs_key_ptr));
869 btrfs_memcpy(root, lower, &lower->ptrs[slot].key,
870 key, sizeof(struct btrfs_disk_key));
871 btrfs_set_node_blockptr(lower, slot, blocknr);
872 btrfs_set_header_nritems(&lower->header, nritems + 1);
873 btrfs_mark_buffer_dirty(path->nodes[level]);
874 check_node(root, path, level);
879 * split the node at the specified level in path in two.
880 * The path is corrected to point to the appropriate node after the split
882 * Before splitting this tries to make some room in the node by pushing
883 * left and right, if either one works, it returns right away.
885 * returns 0 on success and < 0 on failure
887 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
888 *root, struct btrfs_path *path, int level)
890 struct buffer_head *t;
891 struct btrfs_node *c;
892 struct buffer_head *split_buffer;
893 struct btrfs_node *split;
899 t = path->nodes[level];
900 c = btrfs_buffer_node(t);
901 if (t == root->node) {
902 /* trying to split the root, lets make a new one */
903 ret = insert_new_root(trans, root, path, level + 1);
907 ret = push_nodes_for_insert(trans, root, path, level);
908 t = path->nodes[level];
909 c = btrfs_buffer_node(t);
911 btrfs_header_nritems(&c->header) <
912 BTRFS_NODEPTRS_PER_BLOCK(root) - 1)
916 c_nritems = btrfs_header_nritems(&c->header);
917 split_buffer = btrfs_alloc_free_block(trans, root, t->b_blocknr);
918 split = btrfs_buffer_node(split_buffer);
919 btrfs_set_header_flags(&split->header, btrfs_header_flags(&c->header));
920 btrfs_set_header_level(&split->header, btrfs_header_level(&c->header));
921 btrfs_set_header_blocknr(&split->header, bh_blocknr(split_buffer));
922 btrfs_set_header_generation(&split->header, trans->transid);
923 btrfs_set_header_owner(&split->header, root->root_key.objectid);
924 memcpy(split->header.fsid, root->fs_info->disk_super->fsid,
925 sizeof(split->header.fsid));
926 mid = (c_nritems + 1) / 2;
927 btrfs_memcpy(root, split, split->ptrs, c->ptrs + mid,
928 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
929 btrfs_set_header_nritems(&split->header, c_nritems - mid);
930 btrfs_set_header_nritems(&c->header, mid);
933 btrfs_mark_buffer_dirty(t);
934 btrfs_mark_buffer_dirty(split_buffer);
935 wret = insert_ptr(trans, root, path, &split->ptrs[0].key,
936 bh_blocknr(split_buffer), path->slots[level + 1] + 1,
941 if (path->slots[level] >= mid) {
942 path->slots[level] -= mid;
943 btrfs_block_release(root, t);
944 path->nodes[level] = split_buffer;
945 path->slots[level + 1] += 1;
947 btrfs_block_release(root, split_buffer);
953 * how many bytes are required to store the items in a leaf. start
954 * and nr indicate which items in the leaf to check. This totals up the
955 * space used both by the item structs and the item data
957 static int leaf_space_used(struct btrfs_leaf *l, int start, int nr)
960 int nritems = btrfs_header_nritems(&l->header);
961 int end = min(nritems, start + nr) - 1;
965 data_len = btrfs_item_end(l->items + start);
966 data_len = data_len - btrfs_item_offset(l->items + end);
967 data_len += sizeof(struct btrfs_item) * nr;
968 WARN_ON(data_len < 0);
973 * The space between the end of the leaf items and
974 * the start of the leaf data. IOW, how much room
975 * the leaf has left for both items and data
977 int btrfs_leaf_free_space(struct btrfs_root *root, struct btrfs_leaf *leaf)
979 int nritems = btrfs_header_nritems(&leaf->header);
980 return BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
984 * push some data in the path leaf to the right, trying to free up at
985 * least data_size bytes. returns zero if the push worked, nonzero otherwise
987 * returns 1 if the push failed because the other node didn't have enough
988 * room, 0 if everything worked out and < 0 if there were major errors.
990 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
991 *root, struct btrfs_path *path, int data_size)
993 struct buffer_head *left_buf = path->nodes[0];
994 struct btrfs_leaf *left = btrfs_buffer_leaf(left_buf);
995 struct btrfs_leaf *right;
996 struct buffer_head *right_buf;
997 struct buffer_head *upper;
998 struct btrfs_node *upper_node;
1004 struct btrfs_item *item;
1008 slot = path->slots[1];
1009 if (!path->nodes[1]) {
1012 upper = path->nodes[1];
1013 upper_node = btrfs_buffer_node(upper);
1014 if (slot >= btrfs_header_nritems(&upper_node->header) - 1) {
1017 right_buf = read_tree_block(root,
1018 btrfs_node_blockptr(btrfs_buffer_node(upper), slot + 1));
1019 right = btrfs_buffer_leaf(right_buf);
1020 free_space = btrfs_leaf_free_space(root, right);
1021 if (free_space < data_size + sizeof(struct btrfs_item)) {
1022 btrfs_block_release(root, right_buf);
1025 /* cow and double check */
1026 btrfs_cow_block(trans, root, right_buf, upper, slot + 1, &right_buf);
1027 right = btrfs_buffer_leaf(right_buf);
1028 free_space = btrfs_leaf_free_space(root, right);
1029 if (free_space < data_size + sizeof(struct btrfs_item)) {
1030 btrfs_block_release(root, right_buf);
1034 left_nritems = btrfs_header_nritems(&left->header);
1035 if (left_nritems == 0) {
1036 btrfs_block_release(root, right_buf);
1039 for (i = left_nritems - 1; i >= 1; i--) {
1040 item = left->items + i;
1041 if (path->slots[0] == i)
1042 push_space += data_size + sizeof(*item);
1043 if (btrfs_item_size(item) + sizeof(*item) + push_space >
1047 push_space += btrfs_item_size(item) + sizeof(*item);
1049 if (push_items == 0) {
1050 btrfs_block_release(root, right_buf);
1053 if (push_items == left_nritems)
1055 right_nritems = btrfs_header_nritems(&right->header);
1056 /* push left to right */
1057 push_space = btrfs_item_end(left->items + left_nritems - push_items);
1058 push_space -= leaf_data_end(root, left);
1059 /* make room in the right data area */
1060 btrfs_memmove(root, right, btrfs_leaf_data(right) +
1061 leaf_data_end(root, right) - push_space,
1062 btrfs_leaf_data(right) +
1063 leaf_data_end(root, right), BTRFS_LEAF_DATA_SIZE(root) -
1064 leaf_data_end(root, right));
1065 /* copy from the left data area */
1066 btrfs_memcpy(root, right, btrfs_leaf_data(right) +
1067 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1068 btrfs_leaf_data(left) + leaf_data_end(root, left),
1070 btrfs_memmove(root, right, right->items + push_items, right->items,
1071 right_nritems * sizeof(struct btrfs_item));
1072 /* copy the items from left to right */
1073 btrfs_memcpy(root, right, right->items, left->items +
1074 left_nritems - push_items,
1075 push_items * sizeof(struct btrfs_item));
1077 /* update the item pointers */
1078 right_nritems += push_items;
1079 btrfs_set_header_nritems(&right->header, right_nritems);
1080 push_space = BTRFS_LEAF_DATA_SIZE(root);
1081 for (i = 0; i < right_nritems; i++) {
1082 btrfs_set_item_offset(right->items + i, push_space -
1083 btrfs_item_size(right->items + i));
1084 push_space = btrfs_item_offset(right->items + i);
1086 left_nritems -= push_items;
1087 btrfs_set_header_nritems(&left->header, left_nritems);
1089 btrfs_mark_buffer_dirty(left_buf);
1090 btrfs_mark_buffer_dirty(right_buf);
1092 btrfs_memcpy(root, upper_node, &upper_node->ptrs[slot + 1].key,
1093 &right->items[0].key, sizeof(struct btrfs_disk_key));
1094 btrfs_mark_buffer_dirty(upper);
1096 /* then fixup the leaf pointer in the path */
1097 if (path->slots[0] >= left_nritems) {
1098 path->slots[0] -= left_nritems;
1099 btrfs_block_release(root, path->nodes[0]);
1100 path->nodes[0] = right_buf;
1101 path->slots[1] += 1;
1103 btrfs_block_release(root, right_buf);
1106 check_node(root, path, 1);
1110 * push some data in the path leaf to the left, trying to free up at
1111 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1113 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1114 *root, struct btrfs_path *path, int data_size)
1116 struct buffer_head *right_buf = path->nodes[0];
1117 struct btrfs_leaf *right = btrfs_buffer_leaf(right_buf);
1118 struct buffer_head *t;
1119 struct btrfs_leaf *left;
1125 struct btrfs_item *item;
1126 u32 old_left_nritems;
1130 slot = path->slots[1];
1134 if (!path->nodes[1]) {
1137 t = read_tree_block(root,
1138 btrfs_node_blockptr(btrfs_buffer_node(path->nodes[1]), slot - 1));
1139 left = btrfs_buffer_leaf(t);
1140 free_space = btrfs_leaf_free_space(root, left);
1141 if (free_space < data_size + sizeof(struct btrfs_item)) {
1142 btrfs_block_release(root, t);
1146 /* cow and double check */
1147 btrfs_cow_block(trans, root, t, path->nodes[1], slot - 1, &t);
1148 left = btrfs_buffer_leaf(t);
1149 free_space = btrfs_leaf_free_space(root, left);
1150 if (free_space < data_size + sizeof(struct btrfs_item)) {
1151 btrfs_block_release(root, t);
1155 if (btrfs_header_nritems(&right->header) == 0) {
1156 btrfs_block_release(root, t);
1160 for (i = 0; i < btrfs_header_nritems(&right->header) - 1; i++) {
1161 item = right->items + i;
1162 if (path->slots[0] == i)
1163 push_space += data_size + sizeof(*item);
1164 if (btrfs_item_size(item) + sizeof(*item) + push_space >
1168 push_space += btrfs_item_size(item) + sizeof(*item);
1170 if (push_items == 0) {
1171 btrfs_block_release(root, t);
1174 if (push_items == btrfs_header_nritems(&right->header))
1176 /* push data from right to left */
1177 btrfs_memcpy(root, left, left->items +
1178 btrfs_header_nritems(&left->header),
1179 right->items, push_items * sizeof(struct btrfs_item));
1180 push_space = BTRFS_LEAF_DATA_SIZE(root) -
1181 btrfs_item_offset(right->items + push_items -1);
1182 btrfs_memcpy(root, left, btrfs_leaf_data(left) +
1183 leaf_data_end(root, left) - push_space,
1184 btrfs_leaf_data(right) +
1185 btrfs_item_offset(right->items + push_items - 1),
1187 old_left_nritems = btrfs_header_nritems(&left->header);
1188 BUG_ON(old_left_nritems < 0);
1190 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1191 u32 ioff = btrfs_item_offset(left->items + i);
1192 btrfs_set_item_offset(left->items + i, ioff -
1193 (BTRFS_LEAF_DATA_SIZE(root) -
1194 btrfs_item_offset(left->items +
1195 old_left_nritems - 1)));
1197 btrfs_set_header_nritems(&left->header, old_left_nritems + push_items);
1199 /* fixup right node */
1200 push_space = btrfs_item_offset(right->items + push_items - 1) -
1201 leaf_data_end(root, right);
1202 btrfs_memmove(root, right, btrfs_leaf_data(right) +
1203 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1204 btrfs_leaf_data(right) +
1205 leaf_data_end(root, right), push_space);
1206 btrfs_memmove(root, right, right->items, right->items + push_items,
1207 (btrfs_header_nritems(&right->header) - push_items) *
1208 sizeof(struct btrfs_item));
1209 btrfs_set_header_nritems(&right->header,
1210 btrfs_header_nritems(&right->header) -
1212 push_space = BTRFS_LEAF_DATA_SIZE(root);
1214 for (i = 0; i < btrfs_header_nritems(&right->header); i++) {
1215 btrfs_set_item_offset(right->items + i, push_space -
1216 btrfs_item_size(right->items + i));
1217 push_space = btrfs_item_offset(right->items + i);
1220 btrfs_mark_buffer_dirty(t);
1221 btrfs_mark_buffer_dirty(right_buf);
1223 wret = fixup_low_keys(trans, root, path, &right->items[0].key, 1);
1227 /* then fixup the leaf pointer in the path */
1228 if (path->slots[0] < push_items) {
1229 path->slots[0] += old_left_nritems;
1230 btrfs_block_release(root, path->nodes[0]);
1232 path->slots[1] -= 1;
1234 btrfs_block_release(root, t);
1235 path->slots[0] -= push_items;
1237 BUG_ON(path->slots[0] < 0);
1239 check_node(root, path, 1);
1244 * split the path's leaf in two, making sure there is at least data_size
1245 * available for the resulting leaf level of the path.
1247 * returns 0 if all went well and < 0 on failure.
1249 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
1250 *root, struct btrfs_key *ins_key,
1251 struct btrfs_path *path, int data_size)
1253 struct buffer_head *l_buf;
1254 struct btrfs_leaf *l;
1258 struct btrfs_leaf *right;
1259 struct buffer_head *right_buffer;
1260 int space_needed = data_size + sizeof(struct btrfs_item);
1266 int double_split = 0;
1267 struct btrfs_disk_key disk_key;
1269 /* first try to make some room by pushing left and right */
1270 wret = push_leaf_left(trans, root, path, data_size);
1274 wret = push_leaf_right(trans, root, path, data_size);
1278 l_buf = path->nodes[0];
1279 l = btrfs_buffer_leaf(l_buf);
1281 /* did the pushes work? */
1282 if (btrfs_leaf_free_space(root, l) >=
1283 sizeof(struct btrfs_item) + data_size)
1286 if (!path->nodes[1]) {
1287 ret = insert_new_root(trans, root, path, 1);
1291 slot = path->slots[0];
1292 nritems = btrfs_header_nritems(&l->header);
1293 mid = (nritems + 1)/ 2;
1294 right_buffer = btrfs_alloc_free_block(trans, root, l_buf->b_blocknr);
1295 BUG_ON(!right_buffer);
1296 right = btrfs_buffer_leaf(right_buffer);
1297 memset(&right->header, 0, sizeof(right->header));
1298 btrfs_set_header_blocknr(&right->header, bh_blocknr(right_buffer));
1299 btrfs_set_header_generation(&right->header, trans->transid);
1300 btrfs_set_header_owner(&right->header, root->root_key.objectid);
1301 btrfs_set_header_level(&right->header, 0);
1302 memcpy(right->header.fsid, root->fs_info->disk_super->fsid,
1303 sizeof(right->header.fsid));
1306 leaf_space_used(l, mid, nritems - mid) + space_needed >
1307 BTRFS_LEAF_DATA_SIZE(root)) {
1308 if (slot >= nritems) {
1309 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1310 btrfs_set_header_nritems(&right->header, 0);
1311 wret = insert_ptr(trans, root, path,
1313 bh_blocknr(right_buffer),
1314 path->slots[1] + 1, 1);
1317 btrfs_block_release(root, path->nodes[0]);
1318 path->nodes[0] = right_buffer;
1320 path->slots[1] += 1;
1327 if (leaf_space_used(l, 0, mid + 1) + space_needed >
1328 BTRFS_LEAF_DATA_SIZE(root)) {
1330 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1331 btrfs_set_header_nritems(&right->header, 0);
1332 wret = insert_ptr(trans, root, path,
1334 bh_blocknr(right_buffer),
1338 btrfs_block_release(root, path->nodes[0]);
1339 path->nodes[0] = right_buffer;
1341 if (path->slots[1] == 0) {
1342 wret = fixup_low_keys(trans, root,
1343 path, &disk_key, 1);
1353 btrfs_set_header_nritems(&right->header, nritems - mid);
1354 data_copy_size = btrfs_item_end(l->items + mid) -
1355 leaf_data_end(root, l);
1356 btrfs_memcpy(root, right, right->items, l->items + mid,
1357 (nritems - mid) * sizeof(struct btrfs_item));
1358 btrfs_memcpy(root, right,
1359 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
1360 data_copy_size, btrfs_leaf_data(l) +
1361 leaf_data_end(root, l), data_copy_size);
1362 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
1363 btrfs_item_end(l->items + mid);
1365 for (i = 0; i < btrfs_header_nritems(&right->header); i++) {
1366 u32 ioff = btrfs_item_offset(right->items + i);
1367 btrfs_set_item_offset(right->items + i, ioff + rt_data_off);
1370 btrfs_set_header_nritems(&l->header, mid);
1372 wret = insert_ptr(trans, root, path, &right->items[0].key,
1373 bh_blocknr(right_buffer), path->slots[1] + 1, 1);
1376 btrfs_mark_buffer_dirty(right_buffer);
1377 btrfs_mark_buffer_dirty(l_buf);
1378 BUG_ON(path->slots[0] != slot);
1380 btrfs_block_release(root, path->nodes[0]);
1381 path->nodes[0] = right_buffer;
1382 path->slots[0] -= mid;
1383 path->slots[1] += 1;
1385 btrfs_block_release(root, right_buffer);
1386 BUG_ON(path->slots[0] < 0);
1387 check_node(root, path, 1);
1391 right_buffer = btrfs_alloc_free_block(trans, root, l_buf->b_blocknr);
1392 BUG_ON(!right_buffer);
1393 right = btrfs_buffer_leaf(right_buffer);
1394 memset(&right->header, 0, sizeof(right->header));
1395 btrfs_set_header_blocknr(&right->header, bh_blocknr(right_buffer));
1396 btrfs_set_header_generation(&right->header, trans->transid);
1397 btrfs_set_header_owner(&right->header, root->root_key.objectid);
1398 btrfs_set_header_level(&right->header, 0);
1399 memcpy(right->header.fsid, root->fs_info->disk_super->fsid,
1400 sizeof(right->header.fsid));
1401 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1402 btrfs_set_header_nritems(&right->header, 0);
1403 wret = insert_ptr(trans, root, path,
1405 bh_blocknr(right_buffer),
1409 if (path->slots[1] == 0) {
1410 wret = fixup_low_keys(trans, root, path, &disk_key, 1);
1414 btrfs_block_release(root, path->nodes[0]);
1415 path->nodes[0] = right_buffer;
1417 check_node(root, path, 1);
1418 check_leaf(root, path, 0);
1422 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
1423 struct btrfs_root *root,
1424 struct btrfs_path *path,
1430 struct btrfs_leaf *leaf;
1431 struct buffer_head *leaf_buf;
1433 unsigned int data_end;
1434 unsigned int old_data_start;
1435 unsigned int old_size;
1436 unsigned int size_diff;
1439 slot_orig = path->slots[0];
1440 leaf_buf = path->nodes[0];
1441 leaf = btrfs_buffer_leaf(leaf_buf);
1443 nritems = btrfs_header_nritems(&leaf->header);
1444 data_end = leaf_data_end(root, leaf);
1446 slot = path->slots[0];
1447 old_data_start = btrfs_item_offset(leaf->items + slot);
1448 old_size = btrfs_item_size(leaf->items + slot);
1449 BUG_ON(old_size <= new_size);
1450 size_diff = old_size - new_size;
1453 BUG_ON(slot >= nritems);
1456 * item0..itemN ... dataN.offset..dataN.size .. data0.size
1458 /* first correct the data pointers */
1459 for (i = slot; i < nritems; i++) {
1460 u32 ioff = btrfs_item_offset(leaf->items + i);
1461 btrfs_set_item_offset(leaf->items + i,
1464 /* shift the data */
1465 btrfs_memmove(root, leaf, btrfs_leaf_data(leaf) +
1466 data_end + size_diff, btrfs_leaf_data(leaf) +
1467 data_end, old_data_start + new_size - data_end);
1468 btrfs_set_item_size(leaf->items + slot, new_size);
1469 btrfs_mark_buffer_dirty(leaf_buf);
1472 if (btrfs_leaf_free_space(root, leaf) < 0)
1474 check_leaf(root, path, 0);
1478 int btrfs_extend_item(struct btrfs_trans_handle *trans, struct btrfs_root
1479 *root, struct btrfs_path *path, u32 data_size)
1484 struct btrfs_leaf *leaf;
1485 struct buffer_head *leaf_buf;
1487 unsigned int data_end;
1488 unsigned int old_data;
1489 unsigned int old_size;
1492 slot_orig = path->slots[0];
1493 leaf_buf = path->nodes[0];
1494 leaf = btrfs_buffer_leaf(leaf_buf);
1496 nritems = btrfs_header_nritems(&leaf->header);
1497 data_end = leaf_data_end(root, leaf);
1499 if (btrfs_leaf_free_space(root, leaf) < data_size)
1501 slot = path->slots[0];
1502 old_data = btrfs_item_end(leaf->items + slot);
1505 BUG_ON(slot >= nritems);
1508 * item0..itemN ... dataN.offset..dataN.size .. data0.size
1510 /* first correct the data pointers */
1511 for (i = slot; i < nritems; i++) {
1512 u32 ioff = btrfs_item_offset(leaf->items + i);
1513 btrfs_set_item_offset(leaf->items + i,
1516 /* shift the data */
1517 btrfs_memmove(root, leaf, btrfs_leaf_data(leaf) +
1518 data_end - data_size, btrfs_leaf_data(leaf) +
1519 data_end, old_data - data_end);
1520 data_end = old_data;
1521 old_size = btrfs_item_size(leaf->items + slot);
1522 btrfs_set_item_size(leaf->items + slot, old_size + data_size);
1523 btrfs_mark_buffer_dirty(leaf_buf);
1526 if (btrfs_leaf_free_space(root, leaf) < 0)
1528 check_leaf(root, path, 0);
1533 * Given a key and some data, insert an item into the tree.
1534 * This does all the path init required, making room in the tree if needed.
1536 int btrfs_insert_empty_item(struct btrfs_trans_handle *trans, struct btrfs_root
1537 *root, struct btrfs_path *path, struct btrfs_key
1538 *cpu_key, u32 data_size)
1543 struct btrfs_leaf *leaf;
1544 struct buffer_head *leaf_buf;
1546 unsigned int data_end;
1547 struct btrfs_disk_key disk_key;
1549 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
1551 /* create a root if there isn't one */
1554 ret = btrfs_search_slot(trans, root, cpu_key, path, data_size, 1);
1561 slot_orig = path->slots[0];
1562 leaf_buf = path->nodes[0];
1563 leaf = btrfs_buffer_leaf(leaf_buf);
1565 nritems = btrfs_header_nritems(&leaf->header);
1566 data_end = leaf_data_end(root, leaf);
1568 if (btrfs_leaf_free_space(root, leaf) <
1569 sizeof(struct btrfs_item) + data_size) {
1572 slot = path->slots[0];
1574 if (slot != nritems) {
1576 unsigned int old_data = btrfs_item_end(leaf->items + slot);
1579 * item0..itemN ... dataN.offset..dataN.size .. data0.size
1581 /* first correct the data pointers */
1582 for (i = slot; i < nritems; i++) {
1583 u32 ioff = btrfs_item_offset(leaf->items + i);
1584 btrfs_set_item_offset(leaf->items + i,
1588 /* shift the items */
1589 btrfs_memmove(root, leaf, leaf->items + slot + 1,
1591 (nritems - slot) * sizeof(struct btrfs_item));
1593 /* shift the data */
1594 btrfs_memmove(root, leaf, btrfs_leaf_data(leaf) +
1595 data_end - data_size, btrfs_leaf_data(leaf) +
1596 data_end, old_data - data_end);
1597 data_end = old_data;
1599 /* setup the item for the new data */
1600 btrfs_memcpy(root, leaf, &leaf->items[slot].key, &disk_key,
1601 sizeof(struct btrfs_disk_key));
1602 btrfs_set_item_offset(leaf->items + slot, data_end - data_size);
1603 btrfs_set_item_size(leaf->items + slot, data_size);
1604 btrfs_set_header_nritems(&leaf->header, nritems + 1);
1605 btrfs_mark_buffer_dirty(leaf_buf);
1609 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
1611 if (btrfs_leaf_free_space(root, leaf) < 0)
1613 check_leaf(root, path, 0);
1619 * Given a key and some data, insert an item into the tree.
1620 * This does all the path init required, making room in the tree if needed.
1622 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
1623 *root, struct btrfs_key *cpu_key, void *data, u32
1627 struct btrfs_path *path;
1630 path = btrfs_alloc_path();
1632 btrfs_init_path(path);
1633 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
1635 ptr = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
1636 path->slots[0], u8);
1637 btrfs_memcpy(root, path->nodes[0]->b_data,
1638 ptr, data, data_size);
1639 btrfs_mark_buffer_dirty(path->nodes[0]);
1641 btrfs_release_path(root, path);
1642 btrfs_free_path(path);
1647 * delete the pointer from a given node.
1649 * If the delete empties a node, the node is removed from the tree,
1650 * continuing all the way the root if required. The root is converted into
1651 * a leaf if all the nodes are emptied.
1653 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1654 struct btrfs_path *path, int level, int slot)
1656 struct btrfs_node *node;
1657 struct buffer_head *parent = path->nodes[level];
1662 node = btrfs_buffer_node(parent);
1663 nritems = btrfs_header_nritems(&node->header);
1664 if (slot != nritems -1) {
1665 btrfs_memmove(root, node, node->ptrs + slot,
1666 node->ptrs + slot + 1,
1667 sizeof(struct btrfs_key_ptr) *
1668 (nritems - slot - 1));
1671 btrfs_set_header_nritems(&node->header, nritems);
1672 if (nritems == 0 && parent == root->node) {
1673 struct btrfs_header *header = btrfs_buffer_header(root->node);
1674 BUG_ON(btrfs_header_level(header) != 1);
1675 /* just turn the root into a leaf and break */
1676 btrfs_set_header_level(header, 0);
1677 } else if (slot == 0) {
1678 wret = fixup_low_keys(trans, root, path, &node->ptrs[0].key,
1683 btrfs_mark_buffer_dirty(parent);
1688 * delete the item at the leaf level in path. If that empties
1689 * the leaf, remove it from the tree
1691 int btrfs_del_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1692 struct btrfs_path *path)
1695 struct btrfs_leaf *leaf;
1696 struct buffer_head *leaf_buf;
1703 leaf_buf = path->nodes[0];
1704 leaf = btrfs_buffer_leaf(leaf_buf);
1705 slot = path->slots[0];
1706 doff = btrfs_item_offset(leaf->items + slot);
1707 dsize = btrfs_item_size(leaf->items + slot);
1708 nritems = btrfs_header_nritems(&leaf->header);
1710 if (slot != nritems - 1) {
1712 int data_end = leaf_data_end(root, leaf);
1713 btrfs_memmove(root, leaf, btrfs_leaf_data(leaf) +
1715 btrfs_leaf_data(leaf) + data_end,
1717 for (i = slot + 1; i < nritems; i++) {
1718 u32 ioff = btrfs_item_offset(leaf->items + i);
1719 btrfs_set_item_offset(leaf->items + i, ioff + dsize);
1721 btrfs_memmove(root, leaf, leaf->items + slot,
1722 leaf->items + slot + 1,
1723 sizeof(struct btrfs_item) *
1724 (nritems - slot - 1));
1726 btrfs_set_header_nritems(&leaf->header, nritems - 1);
1728 /* delete the leaf if we've emptied it */
1730 if (leaf_buf == root->node) {
1731 btrfs_set_header_level(&leaf->header, 0);
1733 clean_tree_block(trans, root, leaf_buf);
1734 wait_on_buffer(leaf_buf);
1735 wret = del_ptr(trans, root, path, 1, path->slots[1]);
1738 wret = btrfs_free_extent(trans, root,
1739 bh_blocknr(leaf_buf), 1, 1);
1744 int used = leaf_space_used(leaf, 0, nritems);
1746 wret = fixup_low_keys(trans, root, path,
1747 &leaf->items[0].key, 1);
1752 /* delete the leaf if it is mostly empty */
1753 if (used < BTRFS_LEAF_DATA_SIZE(root) / 3) {
1754 /* push_leaf_left fixes the path.
1755 * make sure the path still points to our leaf
1756 * for possible call to del_ptr below
1758 slot = path->slots[1];
1760 wret = push_leaf_left(trans, root, path, 1);
1763 if (path->nodes[0] == leaf_buf &&
1764 btrfs_header_nritems(&leaf->header)) {
1765 wret = push_leaf_right(trans, root, path, 1);
1769 if (btrfs_header_nritems(&leaf->header) == 0) {
1770 u64 blocknr = bh_blocknr(leaf_buf);
1771 clean_tree_block(trans, root, leaf_buf);
1772 wait_on_buffer(leaf_buf);
1773 wret = del_ptr(trans, root, path, 1, slot);
1776 btrfs_block_release(root, leaf_buf);
1777 wret = btrfs_free_extent(trans, root, blocknr,
1782 btrfs_mark_buffer_dirty(leaf_buf);
1783 btrfs_block_release(root, leaf_buf);
1786 btrfs_mark_buffer_dirty(leaf_buf);
1793 * walk up the tree as far as required to find the next leaf.
1794 * returns 0 if it found something or 1 if there are no greater leaves.
1795 * returns < 0 on io errors.
1797 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
1802 struct buffer_head *c;
1803 struct btrfs_node *c_node;
1804 struct buffer_head *next = NULL;
1806 while(level < BTRFS_MAX_LEVEL) {
1807 if (!path->nodes[level])
1809 slot = path->slots[level] + 1;
1810 c = path->nodes[level];
1811 c_node = btrfs_buffer_node(c);
1812 if (slot >= btrfs_header_nritems(&c_node->header)) {
1816 blocknr = btrfs_node_blockptr(c_node, slot);
1818 btrfs_block_release(root, next);
1819 next = read_tree_block(root, blocknr);
1822 path->slots[level] = slot;
1825 c = path->nodes[level];
1826 btrfs_block_release(root, c);
1827 path->nodes[level] = next;
1828 path->slots[level] = 0;
1831 next = read_tree_block(root,
1832 btrfs_node_blockptr(btrfs_buffer_node(next), 0));