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_path *path, int data_size);
10 static int push_node_left(struct btrfs_trans_handle *trans, struct btrfs_root
11 *root, struct buffer_head *dst, struct buffer_head
13 static int balance_node_right(struct btrfs_trans_handle *trans, struct
14 btrfs_root *root, struct buffer_head *dst_buf,
15 struct buffer_head *src_buf);
16 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
17 struct btrfs_path *path, int level, int slot);
19 inline void btrfs_init_path(struct btrfs_path *p)
21 memset(p, 0, sizeof(*p));
24 void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
27 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
30 btrfs_block_release(root, p->nodes[i]);
32 memset(p, 0, sizeof(*p));
35 static int btrfs_cow_block(struct btrfs_trans_handle *trans, struct btrfs_root
36 *root, struct buffer_head *buf, struct buffer_head
37 *parent, int parent_slot, struct buffer_head
40 struct buffer_head *cow;
41 struct btrfs_node *cow_node;
43 if (btrfs_header_generation(btrfs_buffer_header(buf)) ==
48 cow = btrfs_alloc_free_block(trans, root);
49 cow_node = btrfs_buffer_node(cow);
50 memcpy(cow_node, btrfs_buffer_node(buf), root->blocksize);
51 btrfs_set_header_blocknr(&cow_node->header, cow->b_blocknr);
52 btrfs_set_header_generation(&cow_node->header, trans->transid);
54 btrfs_mark_buffer_dirty(cow);
55 btrfs_inc_ref(trans, root, buf);
56 if (buf == root->node) {
59 if (buf != root->commit_root)
60 btrfs_free_extent(trans, root, buf->b_blocknr, 1, 1);
61 btrfs_block_release(root, buf);
63 btrfs_set_node_blockptr(btrfs_buffer_node(parent), parent_slot,
65 btrfs_mark_buffer_dirty(parent);
66 btrfs_free_extent(trans, root, buf->b_blocknr, 1, 1);
68 btrfs_block_release(root, buf);
73 * The leaf data grows from end-to-front in the node.
74 * this returns the address of the start of the last item,
75 * which is the stop of the leaf data stack
77 static inline unsigned int leaf_data_end(struct btrfs_root *root,
78 struct btrfs_leaf *leaf)
80 u32 nr = btrfs_header_nritems(&leaf->header);
82 return BTRFS_LEAF_DATA_SIZE(root);
83 return btrfs_item_offset(leaf->items + nr - 1);
87 * The space between the end of the leaf items and
88 * the start of the leaf data. IOW, how much room
89 * the leaf has left for both items and data
91 int btrfs_leaf_free_space(struct btrfs_root *root, struct btrfs_leaf *leaf)
93 int data_end = leaf_data_end(root, leaf);
94 int nritems = btrfs_header_nritems(&leaf->header);
95 char *items_end = (char *)(leaf->items + nritems + 1);
96 return (char *)(btrfs_leaf_data(leaf) + data_end) - (char *)items_end;
100 * compare two keys in a memcmp fashion
102 static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
106 btrfs_disk_key_to_cpu(&k1, disk);
108 if (k1.objectid > k2->objectid)
110 if (k1.objectid < k2->objectid)
112 if (k1.offset > k2->offset)
114 if (k1.offset < k2->offset)
116 if (k1.flags > k2->flags)
118 if (k1.flags < k2->flags)
123 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
127 struct btrfs_node *parent = NULL;
128 struct btrfs_node *node = btrfs_buffer_node(path->nodes[level]);
130 u32 nritems = btrfs_header_nritems(&node->header);
132 if (path->nodes[level + 1])
133 parent = btrfs_buffer_node(path->nodes[level + 1]);
134 parent_slot = path->slots[level + 1];
135 BUG_ON(nritems == 0);
137 struct btrfs_disk_key *parent_key;
138 parent_key = &parent->ptrs[parent_slot].key;
139 BUG_ON(memcmp(parent_key, &node->ptrs[0].key,
140 sizeof(struct btrfs_disk_key)));
141 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
142 btrfs_header_blocknr(&node->header));
144 BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
145 for (i = 0; nritems > 1 && i < nritems - 2; i++) {
146 struct btrfs_key cpukey;
147 btrfs_disk_key_to_cpu(&cpukey, &node->ptrs[i + 1].key);
148 BUG_ON(comp_keys(&node->ptrs[i].key, &cpukey) >= 0);
153 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
157 struct btrfs_leaf *leaf = btrfs_buffer_leaf(path->nodes[level]);
158 struct btrfs_node *parent = NULL;
160 u32 nritems = btrfs_header_nritems(&leaf->header);
162 if (path->nodes[level + 1])
163 parent = btrfs_buffer_node(path->nodes[level + 1]);
164 parent_slot = path->slots[level + 1];
165 BUG_ON(btrfs_leaf_free_space(root, leaf) < 0);
171 struct btrfs_disk_key *parent_key;
172 parent_key = &parent->ptrs[parent_slot].key;
173 BUG_ON(memcmp(parent_key, &leaf->items[0].key,
174 sizeof(struct btrfs_disk_key)));
175 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
176 btrfs_header_blocknr(&leaf->header));
178 for (i = 0; nritems > 1 && i < nritems - 2; i++) {
179 struct btrfs_key cpukey;
180 btrfs_disk_key_to_cpu(&cpukey, &leaf->items[i + 1].key);
181 BUG_ON(comp_keys(&leaf->items[i].key,
183 BUG_ON(btrfs_item_offset(leaf->items + i) !=
184 btrfs_item_end(leaf->items + i + 1));
186 BUG_ON(btrfs_item_offset(leaf->items + i) +
187 btrfs_item_size(leaf->items + i) !=
188 BTRFS_LEAF_DATA_SIZE(root));
194 static int check_block(struct btrfs_root *root, struct btrfs_path *path,
198 return check_leaf(root, path, level);
199 return check_node(root, path, level);
203 * search for key in the array p. items p are item_size apart
204 * and there are 'max' items in p
205 * the slot in the array is returned via slot, and it points to
206 * the place where you would insert key if it is not found in
209 * slot may point to max if the key is bigger than all of the keys
211 static int generic_bin_search(char *p, int item_size, struct btrfs_key *key,
218 struct btrfs_disk_key *tmp;
221 mid = (low + high) / 2;
222 tmp = (struct btrfs_disk_key *)(p + mid * item_size);
223 ret = comp_keys(tmp, key);
239 * simple bin_search frontend that does the right thing for
242 static int bin_search(struct btrfs_node *c, struct btrfs_key *key, int *slot)
244 if (btrfs_is_leaf(c)) {
245 struct btrfs_leaf *l = (struct btrfs_leaf *)c;
246 return generic_bin_search((void *)l->items,
247 sizeof(struct btrfs_item),
248 key, btrfs_header_nritems(&c->header),
251 return generic_bin_search((void *)c->ptrs,
252 sizeof(struct btrfs_key_ptr),
253 key, btrfs_header_nritems(&c->header),
259 static struct buffer_head *read_node_slot(struct btrfs_root *root,
260 struct buffer_head *parent_buf,
263 struct btrfs_node *node = btrfs_buffer_node(parent_buf);
266 if (slot >= btrfs_header_nritems(&node->header))
268 return read_tree_block(root, btrfs_node_blockptr(node, slot));
271 static int balance_level(struct btrfs_trans_handle *trans, struct btrfs_root
272 *root, struct btrfs_path *path, int level)
274 struct buffer_head *right_buf;
275 struct buffer_head *mid_buf;
276 struct buffer_head *left_buf;
277 struct buffer_head *parent_buf = NULL;
278 struct btrfs_node *right = NULL;
279 struct btrfs_node *mid;
280 struct btrfs_node *left = NULL;
281 struct btrfs_node *parent = NULL;
285 int orig_slot = path->slots[level];
291 mid_buf = path->nodes[level];
292 mid = btrfs_buffer_node(mid_buf);
293 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
295 if (level < BTRFS_MAX_LEVEL - 1)
296 parent_buf = path->nodes[level + 1];
297 pslot = path->slots[level + 1];
300 * deal with the case where there is only one pointer in the root
301 * by promoting the node below to a root
304 struct buffer_head *child;
305 u64 blocknr = mid_buf->b_blocknr;
307 if (btrfs_header_nritems(&mid->header) != 1)
310 /* promote the child to a root */
311 child = read_node_slot(root, mid_buf, 0);
314 path->nodes[level] = NULL;
315 clean_tree_block(trans, root, mid_buf);
316 wait_on_buffer(mid_buf);
317 /* once for the path */
318 btrfs_block_release(root, mid_buf);
319 /* once for the root ptr */
320 btrfs_block_release(root, mid_buf);
321 return btrfs_free_extent(trans, root, blocknr, 1, 1);
323 parent = btrfs_buffer_node(parent_buf);
325 if (btrfs_header_nritems(&mid->header) >
326 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
329 left_buf = read_node_slot(root, parent_buf, pslot - 1);
330 right_buf = read_node_slot(root, parent_buf, pslot + 1);
332 /* first, try to make some room in the middle buffer */
334 btrfs_cow_block(trans, root, left_buf, parent_buf, pslot - 1,
336 left = btrfs_buffer_node(left_buf);
337 orig_slot += btrfs_header_nritems(&left->header);
338 wret = push_node_left(trans, root, left_buf, mid_buf);
344 * then try to empty the right most buffer into the middle
347 btrfs_cow_block(trans, root, right_buf, parent_buf, pslot + 1,
349 right = btrfs_buffer_node(right_buf);
350 wret = push_node_left(trans, root, mid_buf, right_buf);
353 if (btrfs_header_nritems(&right->header) == 0) {
354 u64 blocknr = right_buf->b_blocknr;
355 clean_tree_block(trans, root, right_buf);
356 wait_on_buffer(right_buf);
357 btrfs_block_release(root, right_buf);
360 wret = del_ptr(trans, root, path, level + 1, pslot +
364 wret = btrfs_free_extent(trans, root, blocknr, 1, 1);
368 btrfs_memcpy(root, parent,
369 &parent->ptrs[pslot + 1].key,
371 sizeof(struct btrfs_disk_key));
372 btrfs_mark_buffer_dirty(parent_buf);
375 if (btrfs_header_nritems(&mid->header) == 1) {
377 * we're not allowed to leave a node with one item in the
378 * tree during a delete. A deletion from lower in the tree
379 * could try to delete the only pointer in this node.
380 * So, pull some keys from the left.
381 * There has to be a left pointer at this point because
382 * otherwise we would have pulled some pointers from the
386 wret = balance_node_right(trans, root, mid_buf, left_buf);
391 if (btrfs_header_nritems(&mid->header) == 0) {
392 /* we've managed to empty the middle node, drop it */
393 u64 blocknr = mid_buf->b_blocknr;
394 clean_tree_block(trans, root, mid_buf);
395 wait_on_buffer(mid_buf);
396 btrfs_block_release(root, mid_buf);
399 wret = del_ptr(trans, root, path, level + 1, pslot);
402 wret = btrfs_free_extent(trans, root, blocknr, 1, 1);
406 /* update the parent key to reflect our changes */
407 btrfs_memcpy(root, parent,
408 &parent->ptrs[pslot].key, &mid->ptrs[0].key,
409 sizeof(struct btrfs_disk_key));
410 btrfs_mark_buffer_dirty(parent_buf);
413 /* update the path */
415 if (btrfs_header_nritems(&left->header) > orig_slot) {
417 path->nodes[level] = left_buf;
418 path->slots[level + 1] -= 1;
419 path->slots[level] = orig_slot;
421 btrfs_block_release(root, mid_buf);
423 orig_slot -= btrfs_header_nritems(&left->header);
424 path->slots[level] = orig_slot;
427 /* double check we haven't messed things up */
428 check_block(root, path, level);
430 btrfs_node_blockptr(btrfs_buffer_node(path->nodes[level]),
435 btrfs_block_release(root, right_buf);
437 btrfs_block_release(root, left_buf);
442 * look for key in the tree. path is filled in with nodes along the way
443 * if key is found, we return zero and you can find the item in the leaf
444 * level of the path (level 0)
446 * If the key isn't found, the path points to the slot where it should
447 * be inserted, and 1 is returned. If there are other errors during the
448 * search a negative error number is returned.
450 * if ins_len > 0, nodes and leaves will be split as we walk down the
451 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
454 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
455 *root, struct btrfs_key *key, struct btrfs_path *p, int
458 struct buffer_head *b;
459 struct buffer_head *cow_buf;
460 struct btrfs_node *c;
465 WARN_ON(p->nodes[0] != NULL);
466 WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
471 c = btrfs_buffer_node(b);
472 level = btrfs_header_level(&c->header);
475 wret = btrfs_cow_block(trans, root, b,
481 BUG_ON(!cow && ins_len);
482 c = btrfs_buffer_node(b);
484 ret = check_block(root, p, level);
487 ret = bin_search(c, key, &slot);
488 if (!btrfs_is_leaf(c)) {
491 p->slots[level] = slot;
492 if (ins_len > 0 && btrfs_header_nritems(&c->header) ==
493 BTRFS_NODEPTRS_PER_BLOCK(root)) {
494 int sret = split_node(trans, root, p, level);
499 c = btrfs_buffer_node(b);
500 slot = p->slots[level];
501 } else if (ins_len < 0) {
502 int sret = balance_level(trans, root, p,
509 c = btrfs_buffer_node(b);
510 slot = p->slots[level];
511 BUG_ON(btrfs_header_nritems(&c->header) == 1);
513 b = read_tree_block(root, btrfs_node_blockptr(c, slot));
515 struct btrfs_leaf *l = (struct btrfs_leaf *)c;
516 p->slots[level] = slot;
517 if (ins_len > 0 && btrfs_leaf_free_space(root, l) <
518 sizeof(struct btrfs_item) + ins_len) {
519 int sret = split_leaf(trans, root, p, ins_len);
531 * adjust the pointers going up the tree, starting at level
532 * making sure the right key of each node is points to 'key'.
533 * This is used after shifting pointers to the left, so it stops
534 * fixing up pointers when a given leaf/node is not in slot 0 of the
537 * If this fails to write a tree block, it returns -1, but continues
538 * fixing up the blocks in ram so the tree is consistent.
540 static int fixup_low_keys(struct btrfs_trans_handle *trans, struct btrfs_root
541 *root, struct btrfs_path *path, struct btrfs_disk_key
546 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
547 struct btrfs_node *t;
548 int tslot = path->slots[i];
551 t = btrfs_buffer_node(path->nodes[i]);
552 btrfs_memcpy(root, t, &t->ptrs[tslot].key, key, sizeof(*key));
553 btrfs_mark_buffer_dirty(path->nodes[i]);
561 * try to push data from one node into the next node left in the
564 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
565 * error, and > 0 if there was no room in the left hand block.
567 static int push_node_left(struct btrfs_trans_handle *trans, struct btrfs_root
568 *root, struct buffer_head *dst_buf, struct
569 buffer_head *src_buf)
571 struct btrfs_node *src = btrfs_buffer_node(src_buf);
572 struct btrfs_node *dst = btrfs_buffer_node(dst_buf);
578 src_nritems = btrfs_header_nritems(&src->header);
579 dst_nritems = btrfs_header_nritems(&dst->header);
580 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
581 if (push_items <= 0) {
585 if (src_nritems < push_items)
586 push_items = src_nritems;
588 btrfs_memcpy(root, dst, dst->ptrs + dst_nritems, src->ptrs,
589 push_items * sizeof(struct btrfs_key_ptr));
590 if (push_items < src_nritems) {
591 btrfs_memmove(root, src, src->ptrs, src->ptrs + push_items,
592 (src_nritems - push_items) *
593 sizeof(struct btrfs_key_ptr));
595 btrfs_set_header_nritems(&src->header, src_nritems - push_items);
596 btrfs_set_header_nritems(&dst->header, dst_nritems + push_items);
597 btrfs_mark_buffer_dirty(src_buf);
598 btrfs_mark_buffer_dirty(dst_buf);
603 * try to push data from one node into the next node right in the
606 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
607 * error, and > 0 if there was no room in the right hand block.
609 * this will only push up to 1/2 the contents of the left node over
611 static int balance_node_right(struct btrfs_trans_handle *trans, struct
612 btrfs_root *root, struct buffer_head *dst_buf,
613 struct buffer_head *src_buf)
615 struct btrfs_node *src = btrfs_buffer_node(src_buf);
616 struct btrfs_node *dst = btrfs_buffer_node(dst_buf);
623 src_nritems = btrfs_header_nritems(&src->header);
624 dst_nritems = btrfs_header_nritems(&dst->header);
625 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
626 if (push_items <= 0) {
630 max_push = src_nritems / 2 + 1;
631 /* don't try to empty the node */
632 if (max_push > src_nritems)
634 if (max_push < push_items)
635 push_items = max_push;
637 btrfs_memmove(root, dst, dst->ptrs + push_items, dst->ptrs,
638 dst_nritems * sizeof(struct btrfs_key_ptr));
640 btrfs_memcpy(root, dst, dst->ptrs,
641 src->ptrs + src_nritems - push_items,
642 push_items * sizeof(struct btrfs_key_ptr));
644 btrfs_set_header_nritems(&src->header, src_nritems - push_items);
645 btrfs_set_header_nritems(&dst->header, dst_nritems + push_items);
647 btrfs_mark_buffer_dirty(src_buf);
648 btrfs_mark_buffer_dirty(dst_buf);
653 * helper function to insert a new root level in the tree.
654 * A new node is allocated, and a single item is inserted to
655 * point to the existing root
657 * returns zero on success or < 0 on failure.
659 static int insert_new_root(struct btrfs_trans_handle *trans, struct btrfs_root
660 *root, struct btrfs_path *path, int level)
662 struct buffer_head *t;
663 struct btrfs_node *lower;
664 struct btrfs_node *c;
665 struct btrfs_disk_key *lower_key;
667 BUG_ON(path->nodes[level]);
668 BUG_ON(path->nodes[level-1] != root->node);
670 t = btrfs_alloc_free_block(trans, root);
671 c = btrfs_buffer_node(t);
672 memset(c, 0, root->blocksize);
673 btrfs_set_header_nritems(&c->header, 1);
674 btrfs_set_header_level(&c->header, level);
675 btrfs_set_header_blocknr(&c->header, t->b_blocknr);
676 btrfs_set_header_generation(&c->header, trans->transid);
677 btrfs_set_header_parentid(&c->header,
678 btrfs_header_parentid(btrfs_buffer_header(root->node)));
679 lower = btrfs_buffer_node(path->nodes[level-1]);
680 if (btrfs_is_leaf(lower))
681 lower_key = &((struct btrfs_leaf *)lower)->items[0].key;
683 lower_key = &lower->ptrs[0].key;
684 btrfs_memcpy(root, c, &c->ptrs[0].key, lower_key,
685 sizeof(struct btrfs_disk_key));
686 btrfs_set_node_blockptr(c, 0, path->nodes[level - 1]->b_blocknr);
688 btrfs_mark_buffer_dirty(t);
690 /* the super has an extra ref to root->node */
691 btrfs_block_release(root, root->node);
694 path->nodes[level] = t;
695 path->slots[level] = 0;
700 * worker function to insert a single pointer in a node.
701 * the node should have enough room for the pointer already
703 * slot and level indicate where you want the key to go, and
704 * blocknr is the block the key points to.
706 * returns zero on success and < 0 on any error
708 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
709 *root, struct btrfs_path *path, struct btrfs_disk_key
710 *key, u64 blocknr, int slot, int level)
712 struct btrfs_node *lower;
715 BUG_ON(!path->nodes[level]);
716 lower = btrfs_buffer_node(path->nodes[level]);
717 nritems = btrfs_header_nritems(&lower->header);
720 if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
722 if (slot != nritems) {
723 btrfs_memmove(root, lower, lower->ptrs + slot + 1,
725 (nritems - slot) * sizeof(struct btrfs_key_ptr));
727 btrfs_memcpy(root, lower, &lower->ptrs[slot].key,
728 key, sizeof(struct btrfs_disk_key));
729 btrfs_set_node_blockptr(lower, slot, blocknr);
730 btrfs_set_header_nritems(&lower->header, nritems + 1);
731 btrfs_mark_buffer_dirty(path->nodes[level]);
736 * split the node at the specified level in path in two.
737 * The path is corrected to point to the appropriate node after the split
739 * Before splitting this tries to make some room in the node by pushing
740 * left and right, if either one works, it returns right away.
742 * returns 0 on success and < 0 on failure
744 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
745 *root, struct btrfs_path *path, int level)
747 struct buffer_head *t;
748 struct btrfs_node *c;
749 struct buffer_head *split_buffer;
750 struct btrfs_node *split;
756 t = path->nodes[level];
757 c = btrfs_buffer_node(t);
758 if (t == root->node) {
759 /* trying to split the root, lets make a new one */
760 ret = insert_new_root(trans, root, path, level + 1);
764 c_nritems = btrfs_header_nritems(&c->header);
765 split_buffer = btrfs_alloc_free_block(trans, root);
766 split = btrfs_buffer_node(split_buffer);
767 btrfs_set_header_flags(&split->header, btrfs_header_flags(&c->header));
768 btrfs_set_header_level(&split->header, btrfs_header_level(&c->header));
769 btrfs_set_header_blocknr(&split->header, split_buffer->b_blocknr);
770 btrfs_set_header_generation(&split->header, trans->transid);
771 btrfs_set_header_parentid(&split->header,
772 btrfs_header_parentid(btrfs_buffer_header(root->node)));
773 mid = (c_nritems + 1) / 2;
774 btrfs_memcpy(root, split, split->ptrs, c->ptrs + mid,
775 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
776 btrfs_set_header_nritems(&split->header, c_nritems - mid);
777 btrfs_set_header_nritems(&c->header, mid);
780 btrfs_mark_buffer_dirty(t);
781 btrfs_mark_buffer_dirty(split_buffer);
782 wret = insert_ptr(trans, root, path, &split->ptrs[0].key,
783 split_buffer->b_blocknr, path->slots[level + 1] + 1,
788 if (path->slots[level] >= mid) {
789 path->slots[level] -= mid;
790 btrfs_block_release(root, t);
791 path->nodes[level] = split_buffer;
792 path->slots[level + 1] += 1;
794 btrfs_block_release(root, split_buffer);
800 * how many bytes are required to store the items in a leaf. start
801 * and nr indicate which items in the leaf to check. This totals up the
802 * space used both by the item structs and the item data
804 static int leaf_space_used(struct btrfs_leaf *l, int start, int nr)
807 int end = start + nr - 1;
811 data_len = btrfs_item_end(l->items + start);
812 data_len = data_len - btrfs_item_offset(l->items + end);
813 data_len += sizeof(struct btrfs_item) * nr;
818 * push some data in the path leaf to the right, trying to free up at
819 * least data_size bytes. returns zero if the push worked, nonzero otherwise
821 * returns 1 if the push failed because the other node didn't have enough
822 * room, 0 if everything worked out and < 0 if there were major errors.
824 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
825 *root, struct btrfs_path *path, int data_size)
827 struct buffer_head *left_buf = path->nodes[0];
828 struct btrfs_leaf *left = btrfs_buffer_leaf(left_buf);
829 struct btrfs_leaf *right;
830 struct buffer_head *right_buf;
831 struct buffer_head *upper;
832 struct btrfs_node *upper_node;
838 struct btrfs_item *item;
842 slot = path->slots[1];
843 if (!path->nodes[1]) {
846 upper = path->nodes[1];
847 upper_node = btrfs_buffer_node(upper);
848 if (slot >= btrfs_header_nritems(&upper_node->header) - 1) {
851 right_buf = read_tree_block(root,
852 btrfs_node_blockptr(btrfs_buffer_node(upper), slot + 1));
853 right = btrfs_buffer_leaf(right_buf);
854 free_space = btrfs_leaf_free_space(root, right);
855 if (free_space < data_size + sizeof(struct btrfs_item)) {
856 btrfs_block_release(root, right_buf);
859 /* cow and double check */
860 btrfs_cow_block(trans, root, right_buf, upper, slot + 1, &right_buf);
861 right = btrfs_buffer_leaf(right_buf);
862 free_space = btrfs_leaf_free_space(root, right);
863 if (free_space < data_size + sizeof(struct btrfs_item)) {
864 btrfs_block_release(root, right_buf);
868 left_nritems = btrfs_header_nritems(&left->header);
869 for (i = left_nritems - 1; i >= 0; i--) {
870 item = left->items + i;
871 if (path->slots[0] == i)
872 push_space += data_size + sizeof(*item);
873 if (btrfs_item_size(item) + sizeof(*item) + push_space >
877 push_space += btrfs_item_size(item) + sizeof(*item);
879 if (push_items == 0) {
880 btrfs_block_release(root, right_buf);
883 right_nritems = btrfs_header_nritems(&right->header);
884 /* push left to right */
885 push_space = btrfs_item_end(left->items + left_nritems - push_items);
886 push_space -= leaf_data_end(root, left);
887 /* make room in the right data area */
888 btrfs_memmove(root, right, btrfs_leaf_data(right) +
889 leaf_data_end(root, right) - push_space,
890 btrfs_leaf_data(right) +
891 leaf_data_end(root, right), BTRFS_LEAF_DATA_SIZE(root) -
892 leaf_data_end(root, right));
893 /* copy from the left data area */
894 btrfs_memcpy(root, right, btrfs_leaf_data(right) +
895 BTRFS_LEAF_DATA_SIZE(root) - push_space,
896 btrfs_leaf_data(left) + leaf_data_end(root, left),
898 btrfs_memmove(root, right, right->items + push_items, right->items,
899 right_nritems * sizeof(struct btrfs_item));
900 /* copy the items from left to right */
901 btrfs_memcpy(root, right, right->items, left->items +
902 left_nritems - push_items,
903 push_items * sizeof(struct btrfs_item));
905 /* update the item pointers */
906 right_nritems += push_items;
907 btrfs_set_header_nritems(&right->header, right_nritems);
908 push_space = BTRFS_LEAF_DATA_SIZE(root);
909 for (i = 0; i < right_nritems; i++) {
910 btrfs_set_item_offset(right->items + i, push_space -
911 btrfs_item_size(right->items + i));
912 push_space = btrfs_item_offset(right->items + i);
914 left_nritems -= push_items;
915 btrfs_set_header_nritems(&left->header, left_nritems);
917 btrfs_mark_buffer_dirty(left_buf);
918 btrfs_mark_buffer_dirty(right_buf);
919 btrfs_memcpy(root, upper_node, &upper_node->ptrs[slot + 1].key,
920 &right->items[0].key, sizeof(struct btrfs_disk_key));
921 btrfs_mark_buffer_dirty(upper);
923 /* then fixup the leaf pointer in the path */
924 if (path->slots[0] >= left_nritems) {
925 path->slots[0] -= left_nritems;
926 btrfs_block_release(root, path->nodes[0]);
927 path->nodes[0] = right_buf;
930 btrfs_block_release(root, right_buf);
935 * push some data in the path leaf to the left, trying to free up at
936 * least data_size bytes. returns zero if the push worked, nonzero otherwise
938 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
939 *root, struct btrfs_path *path, int data_size)
941 struct buffer_head *right_buf = path->nodes[0];
942 struct btrfs_leaf *right = btrfs_buffer_leaf(right_buf);
943 struct buffer_head *t;
944 struct btrfs_leaf *left;
950 struct btrfs_item *item;
951 u32 old_left_nritems;
955 slot = path->slots[1];
959 if (!path->nodes[1]) {
962 t = read_tree_block(root,
963 btrfs_node_blockptr(btrfs_buffer_node(path->nodes[1]), slot - 1));
964 left = btrfs_buffer_leaf(t);
965 free_space = btrfs_leaf_free_space(root, left);
966 if (free_space < data_size + sizeof(struct btrfs_item)) {
967 btrfs_block_release(root, t);
971 /* cow and double check */
972 btrfs_cow_block(trans, root, t, path->nodes[1], slot - 1, &t);
973 left = btrfs_buffer_leaf(t);
974 free_space = btrfs_leaf_free_space(root, left);
975 if (free_space < data_size + sizeof(struct btrfs_item)) {
976 btrfs_block_release(root, t);
980 for (i = 0; i < btrfs_header_nritems(&right->header); i++) {
981 item = right->items + i;
982 if (path->slots[0] == i)
983 push_space += data_size + sizeof(*item);
984 if (btrfs_item_size(item) + sizeof(*item) + push_space >
988 push_space += btrfs_item_size(item) + sizeof(*item);
990 if (push_items == 0) {
991 btrfs_block_release(root, t);
994 /* push data from right to left */
995 btrfs_memcpy(root, left, left->items +
996 btrfs_header_nritems(&left->header),
997 right->items, push_items * sizeof(struct btrfs_item));
998 push_space = BTRFS_LEAF_DATA_SIZE(root) -
999 btrfs_item_offset(right->items + push_items -1);
1000 btrfs_memcpy(root, left, btrfs_leaf_data(left) +
1001 leaf_data_end(root, left) - push_space,
1002 btrfs_leaf_data(right) +
1003 btrfs_item_offset(right->items + push_items - 1),
1005 old_left_nritems = btrfs_header_nritems(&left->header);
1006 BUG_ON(old_left_nritems < 0);
1008 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1009 u32 ioff = btrfs_item_offset(left->items + i);
1010 btrfs_set_item_offset(left->items + i, ioff -
1011 (BTRFS_LEAF_DATA_SIZE(root) -
1012 btrfs_item_offset(left->items +
1013 old_left_nritems - 1)));
1015 btrfs_set_header_nritems(&left->header, old_left_nritems + push_items);
1017 /* fixup right node */
1018 push_space = btrfs_item_offset(right->items + push_items - 1) -
1019 leaf_data_end(root, right);
1020 btrfs_memmove(root, right, btrfs_leaf_data(right) +
1021 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1022 btrfs_leaf_data(right) +
1023 leaf_data_end(root, right), push_space);
1024 btrfs_memmove(root, right, right->items, right->items + push_items,
1025 (btrfs_header_nritems(&right->header) - push_items) *
1026 sizeof(struct btrfs_item));
1027 btrfs_set_header_nritems(&right->header,
1028 btrfs_header_nritems(&right->header) -
1030 push_space = BTRFS_LEAF_DATA_SIZE(root);
1032 for (i = 0; i < btrfs_header_nritems(&right->header); i++) {
1033 btrfs_set_item_offset(right->items + i, push_space -
1034 btrfs_item_size(right->items + i));
1035 push_space = btrfs_item_offset(right->items + i);
1038 btrfs_mark_buffer_dirty(t);
1039 btrfs_mark_buffer_dirty(right_buf);
1041 wret = fixup_low_keys(trans, root, path, &right->items[0].key, 1);
1045 /* then fixup the leaf pointer in the path */
1046 if (path->slots[0] < push_items) {
1047 path->slots[0] += old_left_nritems;
1048 btrfs_block_release(root, path->nodes[0]);
1050 path->slots[1] -= 1;
1052 btrfs_block_release(root, t);
1053 path->slots[0] -= push_items;
1055 BUG_ON(path->slots[0] < 0);
1060 * split the path's leaf in two, making sure there is at least data_size
1061 * available for the resulting leaf level of the path.
1063 * returns 0 if all went well and < 0 on failure.
1065 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
1066 *root, struct btrfs_path *path, int data_size)
1068 struct buffer_head *l_buf;
1069 struct btrfs_leaf *l;
1073 struct btrfs_leaf *right;
1074 struct buffer_head *right_buffer;
1075 int space_needed = data_size + sizeof(struct btrfs_item);
1082 /* first try to make some room by pushing left and right */
1083 wret = push_leaf_left(trans, root, path, data_size);
1087 wret = push_leaf_right(trans, root, path, data_size);
1091 l_buf = path->nodes[0];
1092 l = btrfs_buffer_leaf(l_buf);
1094 /* did the pushes work? */
1095 if (btrfs_leaf_free_space(root, l) >=
1096 sizeof(struct btrfs_item) + data_size)
1099 if (!path->nodes[1]) {
1100 ret = insert_new_root(trans, root, path, 1);
1104 slot = path->slots[0];
1105 nritems = btrfs_header_nritems(&l->header);
1106 mid = (nritems + 1)/ 2;
1107 right_buffer = btrfs_alloc_free_block(trans, root);
1108 BUG_ON(!right_buffer);
1109 BUG_ON(mid == nritems);
1110 right = btrfs_buffer_leaf(right_buffer);
1111 memset(&right->header, 0, sizeof(right->header));
1113 /* FIXME, just alloc a new leaf here */
1114 if (leaf_space_used(l, mid, nritems - mid) + space_needed >
1115 BTRFS_LEAF_DATA_SIZE(root))
1118 /* FIXME, just alloc a new leaf here */
1119 if (leaf_space_used(l, 0, mid + 1) + space_needed >
1120 BTRFS_LEAF_DATA_SIZE(root))
1123 btrfs_set_header_nritems(&right->header, nritems - mid);
1124 btrfs_set_header_blocknr(&right->header, right_buffer->b_blocknr);
1125 btrfs_set_header_generation(&right->header, trans->transid);
1126 btrfs_set_header_level(&right->header, 0);
1127 btrfs_set_header_parentid(&right->header,
1128 btrfs_header_parentid(btrfs_buffer_header(root->node)));
1129 data_copy_size = btrfs_item_end(l->items + mid) -
1130 leaf_data_end(root, l);
1131 btrfs_memcpy(root, right, right->items, l->items + mid,
1132 (nritems - mid) * sizeof(struct btrfs_item));
1133 btrfs_memcpy(root, right,
1134 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
1135 data_copy_size, btrfs_leaf_data(l) +
1136 leaf_data_end(root, l), data_copy_size);
1137 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
1138 btrfs_item_end(l->items + mid);
1140 for (i = 0; i < btrfs_header_nritems(&right->header); i++) {
1141 u32 ioff = btrfs_item_offset(right->items + i);
1142 btrfs_set_item_offset(right->items + i, ioff + rt_data_off);
1145 btrfs_set_header_nritems(&l->header, mid);
1147 wret = insert_ptr(trans, root, path, &right->items[0].key,
1148 right_buffer->b_blocknr, path->slots[1] + 1, 1);
1151 btrfs_mark_buffer_dirty(right_buffer);
1152 btrfs_mark_buffer_dirty(l_buf);
1153 BUG_ON(path->slots[0] != slot);
1155 btrfs_block_release(root, path->nodes[0]);
1156 path->nodes[0] = right_buffer;
1157 path->slots[0] -= mid;
1158 path->slots[1] += 1;
1160 btrfs_block_release(root, right_buffer);
1161 BUG_ON(path->slots[0] < 0);
1166 * Given a key and some data, insert an item into the tree.
1167 * This does all the path init required, making room in the tree if needed.
1169 int btrfs_insert_empty_item(struct btrfs_trans_handle *trans, struct btrfs_root
1170 *root, struct btrfs_path *path, struct btrfs_key
1171 *cpu_key, u32 data_size)
1176 struct btrfs_leaf *leaf;
1177 struct buffer_head *leaf_buf;
1179 unsigned int data_end;
1180 struct btrfs_disk_key disk_key;
1182 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
1184 /* create a root if there isn't one */
1187 ret = btrfs_search_slot(trans, root, cpu_key, path, data_size, 1);
1194 slot_orig = path->slots[0];
1195 leaf_buf = path->nodes[0];
1196 leaf = btrfs_buffer_leaf(leaf_buf);
1198 nritems = btrfs_header_nritems(&leaf->header);
1199 data_end = leaf_data_end(root, leaf);
1201 if (btrfs_leaf_free_space(root, leaf) <
1202 sizeof(struct btrfs_item) + data_size)
1205 slot = path->slots[0];
1207 if (slot != nritems) {
1209 unsigned int old_data = btrfs_item_end(leaf->items + slot);
1212 * item0..itemN ... dataN.offset..dataN.size .. data0.size
1214 /* first correct the data pointers */
1215 for (i = slot; i < nritems; i++) {
1216 u32 ioff = btrfs_item_offset(leaf->items + i);
1217 btrfs_set_item_offset(leaf->items + i,
1221 /* shift the items */
1222 btrfs_memmove(root, leaf, leaf->items + slot + 1,
1224 (nritems - slot) * sizeof(struct btrfs_item));
1226 /* shift the data */
1227 btrfs_memmove(root, leaf, btrfs_leaf_data(leaf) +
1228 data_end - data_size, btrfs_leaf_data(leaf) +
1229 data_end, old_data - data_end);
1230 data_end = old_data;
1232 /* setup the item for the new data */
1233 btrfs_memcpy(root, leaf, &leaf->items[slot].key, &disk_key,
1234 sizeof(struct btrfs_disk_key));
1235 btrfs_set_item_offset(leaf->items + slot, data_end - data_size);
1236 btrfs_set_item_size(leaf->items + slot, data_size);
1237 btrfs_set_header_nritems(&leaf->header, nritems + 1);
1238 btrfs_mark_buffer_dirty(leaf_buf);
1242 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
1244 if (btrfs_leaf_free_space(root, leaf) < 0)
1246 check_leaf(root, path, 0);
1252 * Given a key and some data, insert an item into the tree.
1253 * This does all the path init required, making room in the tree if needed.
1255 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
1256 *root, struct btrfs_key *cpu_key, void *data, u32
1260 struct btrfs_path path;
1263 btrfs_init_path(&path);
1264 ret = btrfs_insert_empty_item(trans, root, &path, cpu_key, data_size);
1266 ptr = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]),
1268 btrfs_memcpy(root, path.nodes[0]->b_data,
1269 ptr, data, data_size);
1270 btrfs_mark_buffer_dirty(path.nodes[0]);
1272 btrfs_release_path(root, &path);
1277 * delete the pointer from a given node.
1279 * If the delete empties a node, the node is removed from the tree,
1280 * continuing all the way the root if required. The root is converted into
1281 * a leaf if all the nodes are emptied.
1283 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1284 struct btrfs_path *path, int level, int slot)
1286 struct btrfs_node *node;
1287 struct buffer_head *parent = path->nodes[level];
1292 node = btrfs_buffer_node(parent);
1293 nritems = btrfs_header_nritems(&node->header);
1294 if (slot != nritems -1) {
1295 btrfs_memmove(root, node, node->ptrs + slot,
1296 node->ptrs + slot + 1,
1297 sizeof(struct btrfs_key_ptr) *
1298 (nritems - slot - 1));
1301 btrfs_set_header_nritems(&node->header, nritems);
1302 if (nritems == 0 && parent == root->node) {
1303 struct btrfs_header *header = btrfs_buffer_header(root->node);
1304 BUG_ON(btrfs_header_level(header) != 1);
1305 /* just turn the root into a leaf and break */
1306 btrfs_set_header_level(header, 0);
1307 } else if (slot == 0) {
1308 wret = fixup_low_keys(trans, root, path, &node->ptrs[0].key,
1313 btrfs_mark_buffer_dirty(parent);
1318 * delete the item at the leaf level in path. If that empties
1319 * the leaf, remove it from the tree
1321 int btrfs_del_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1322 struct btrfs_path *path)
1325 struct btrfs_leaf *leaf;
1326 struct buffer_head *leaf_buf;
1333 leaf_buf = path->nodes[0];
1334 leaf = btrfs_buffer_leaf(leaf_buf);
1335 slot = path->slots[0];
1336 doff = btrfs_item_offset(leaf->items + slot);
1337 dsize = btrfs_item_size(leaf->items + slot);
1338 nritems = btrfs_header_nritems(&leaf->header);
1340 if (slot != nritems - 1) {
1342 int data_end = leaf_data_end(root, leaf);
1343 btrfs_memmove(root, leaf, btrfs_leaf_data(leaf) +
1345 btrfs_leaf_data(leaf) + data_end,
1347 for (i = slot + 1; i < nritems; i++) {
1348 u32 ioff = btrfs_item_offset(leaf->items + i);
1349 btrfs_set_item_offset(leaf->items + i, ioff + dsize);
1351 btrfs_memmove(root, leaf, leaf->items + slot,
1352 leaf->items + slot + 1,
1353 sizeof(struct btrfs_item) *
1354 (nritems - slot - 1));
1356 btrfs_set_header_nritems(&leaf->header, nritems - 1);
1358 /* delete the leaf if we've emptied it */
1360 if (leaf_buf == root->node) {
1361 btrfs_set_header_level(&leaf->header, 0);
1363 clean_tree_block(trans, root, leaf_buf);
1364 wait_on_buffer(leaf_buf);
1365 wret = del_ptr(trans, root, path, 1, path->slots[1]);
1368 wret = btrfs_free_extent(trans, root,
1369 leaf_buf->b_blocknr, 1, 1);
1374 int used = leaf_space_used(leaf, 0, nritems);
1376 wret = fixup_low_keys(trans, root, path,
1377 &leaf->items[0].key, 1);
1382 /* delete the leaf if it is mostly empty */
1383 if (used < BTRFS_LEAF_DATA_SIZE(root) / 3) {
1384 /* push_leaf_left fixes the path.
1385 * make sure the path still points to our leaf
1386 * for possible call to del_ptr below
1388 slot = path->slots[1];
1390 wret = push_leaf_left(trans, root, path, 1);
1393 if (path->nodes[0] == leaf_buf &&
1394 btrfs_header_nritems(&leaf->header)) {
1395 wret = push_leaf_right(trans, root, path, 1);
1399 if (btrfs_header_nritems(&leaf->header) == 0) {
1400 u64 blocknr = leaf_buf->b_blocknr;
1401 clean_tree_block(trans, root, leaf_buf);
1402 wait_on_buffer(leaf_buf);
1403 wret = del_ptr(trans, root, path, 1, slot);
1406 btrfs_block_release(root, leaf_buf);
1407 wret = btrfs_free_extent(trans, root, blocknr,
1412 btrfs_mark_buffer_dirty(leaf_buf);
1413 btrfs_block_release(root, leaf_buf);
1416 btrfs_mark_buffer_dirty(leaf_buf);
1423 * walk up the tree as far as required to find the next leaf.
1424 * returns 0 if it found something or 1 if there are no greater leaves.
1425 * returns < 0 on io errors.
1427 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
1432 struct buffer_head *c;
1433 struct btrfs_node *c_node;
1434 struct buffer_head *next = NULL;
1436 while(level < BTRFS_MAX_LEVEL) {
1437 if (!path->nodes[level])
1439 slot = path->slots[level] + 1;
1440 c = path->nodes[level];
1441 c_node = btrfs_buffer_node(c);
1442 if (slot >= btrfs_header_nritems(&c_node->header)) {
1446 blocknr = btrfs_node_blockptr(c_node, slot);
1448 btrfs_block_release(root, next);
1449 next = read_tree_block(root, blocknr);
1452 path->slots[level] = slot;
1455 c = path->nodes[level];
1456 btrfs_block_release(root, c);
1457 path->nodes[level] = next;
1458 path->slots[level] = 0;
1461 next = read_tree_block(root,
1462 btrfs_node_blockptr(btrfs_buffer_node(next), 0));