2 * Copyright (C) 2007 Oracle. All rights reserved.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
21 #include "transaction.h"
23 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
24 *root, struct btrfs_path *path, int level);
25 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
26 *root, struct btrfs_key *ins_key,
27 struct btrfs_path *path, int data_size);
28 static int push_node_left(struct btrfs_trans_handle *trans, struct btrfs_root
29 *root, struct buffer_head *dst, struct buffer_head
31 static int balance_node_right(struct btrfs_trans_handle *trans, struct
32 btrfs_root *root, struct buffer_head *dst_buf,
33 struct buffer_head *src_buf);
34 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
35 struct btrfs_path *path, int level, int slot);
37 inline void btrfs_init_path(struct btrfs_path *p)
39 memset(p, 0, sizeof(*p));
42 struct btrfs_path *btrfs_alloc_path(void)
44 struct btrfs_path *path;
45 path = kmem_cache_alloc(btrfs_path_cachep, GFP_NOFS);
47 btrfs_init_path(path);
51 void btrfs_free_path(struct btrfs_path *p)
53 btrfs_release_path(NULL, p);
54 kmem_cache_free(btrfs_path_cachep, p);
57 void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
60 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
63 btrfs_block_release(root, p->nodes[i]);
65 memset(p, 0, sizeof(*p));
68 static int __btrfs_cow_block(struct btrfs_trans_handle *trans, struct btrfs_root
69 *root, struct buffer_head *buf, struct buffer_head
70 *parent, int parent_slot, struct buffer_head
71 **cow_ret, u64 search_start, u64 empty_size)
73 struct buffer_head *cow;
74 struct btrfs_node *cow_node;
76 int different_trans = 0;
78 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
79 WARN_ON(!buffer_uptodate(buf));
80 cow = btrfs_alloc_free_block(trans, root, search_start, empty_size);
84 cow_node = btrfs_buffer_node(cow);
85 if (buf->b_size != root->blocksize || cow->b_size != root->blocksize)
88 memcpy(cow_node, btrfs_buffer_node(buf), root->blocksize);
89 btrfs_set_header_blocknr(&cow_node->header, bh_blocknr(cow));
90 btrfs_set_header_generation(&cow_node->header, trans->transid);
91 btrfs_set_header_owner(&cow_node->header, root->root_key.objectid);
93 WARN_ON(btrfs_header_generation(btrfs_buffer_header(buf)) >
95 if (btrfs_header_generation(btrfs_buffer_header(buf)) !=
98 ret = btrfs_inc_ref(trans, root, buf);
102 WARN_ON(!root->ref_cows);
103 clean_tree_block(trans, root, buf);
106 if (buf == root->node) {
109 if (buf != root->commit_root) {
110 btrfs_free_extent(trans, root, bh_blocknr(buf), 1, 1);
112 btrfs_block_release(root, buf);
114 btrfs_set_node_blockptr(btrfs_buffer_node(parent), parent_slot,
116 btrfs_mark_buffer_dirty(parent);
117 WARN_ON(btrfs_header_generation(btrfs_buffer_header(parent)) !=
119 btrfs_free_extent(trans, root, bh_blocknr(buf), 1, 1);
121 btrfs_block_release(root, buf);
122 btrfs_mark_buffer_dirty(cow);
127 int btrfs_cow_block(struct btrfs_trans_handle *trans, struct btrfs_root
128 *root, struct buffer_head *buf, struct buffer_head
129 *parent, int parent_slot, struct buffer_head
133 if (trans->transaction != root->fs_info->running_transaction) {
134 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
135 root->fs_info->running_transaction->transid);
138 if (trans->transid != root->fs_info->generation) {
139 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
140 root->fs_info->generation);
143 if (btrfs_header_generation(btrfs_buffer_header(buf)) ==
149 search_start = bh_blocknr(buf) & ~((u64)65535);
150 return __btrfs_cow_block(trans, root, buf, parent,
151 parent_slot, cow_ret, search_start, 0);
154 static int close_blocks(u64 blocknr, u64 other)
156 if (blocknr < other && other - blocknr < 8)
158 if (blocknr > other && blocknr - other < 8)
163 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
164 struct btrfs_root *root, struct buffer_head *parent,
167 struct btrfs_node *parent_node;
168 struct buffer_head *cur_bh;
169 struct buffer_head *tmp_bh;
171 u64 search_start = 0;
179 if (trans->transaction != root->fs_info->running_transaction) {
180 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
181 root->fs_info->running_transaction->transid);
184 if (trans->transid != root->fs_info->generation) {
185 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
186 root->fs_info->generation);
189 parent_node = btrfs_buffer_node(parent);
190 parent_nritems = btrfs_header_nritems(&parent_node->header);
193 end_slot = parent_nritems;
195 if (parent_nritems == 1)
198 for (i = start_slot; i < end_slot; i++) {
200 blocknr = btrfs_node_blockptr(parent_node, i);
202 other = btrfs_node_blockptr(parent_node, i - 1);
203 close = close_blocks(blocknr, other);
205 if (close && i < end_slot - 1) {
206 other = btrfs_node_blockptr(parent_node, i + 1);
207 close = close_blocks(blocknr, other);
212 cur_bh = btrfs_find_tree_block(root, blocknr);
213 if (!cur_bh || !buffer_uptodate(cur_bh) ||
214 buffer_locked(cur_bh)) {
220 cur_bh = read_tree_block(root, blocknr);
222 if (search_start == 0) {
223 search_start = bh_blocknr(cur_bh) & ~((u64)65535);
225 err = __btrfs_cow_block(trans, root, cur_bh, parent, i,
226 &tmp_bh, search_start,
227 min(8, end_slot - i));
230 search_start = bh_blocknr(tmp_bh);
237 * The leaf data grows from end-to-front in the node.
238 * this returns the address of the start of the last item,
239 * which is the stop of the leaf data stack
241 static inline unsigned int leaf_data_end(struct btrfs_root *root,
242 struct btrfs_leaf *leaf)
244 u32 nr = btrfs_header_nritems(&leaf->header);
246 return BTRFS_LEAF_DATA_SIZE(root);
247 return btrfs_item_offset(leaf->items + nr - 1);
251 * compare two keys in a memcmp fashion
253 static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
257 btrfs_disk_key_to_cpu(&k1, disk);
259 if (k1.objectid > k2->objectid)
261 if (k1.objectid < k2->objectid)
263 if (k1.flags > k2->flags)
265 if (k1.flags < k2->flags)
267 if (k1.offset > k2->offset)
269 if (k1.offset < k2->offset)
274 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
277 struct btrfs_node *parent = NULL;
278 struct btrfs_node *node = btrfs_buffer_node(path->nodes[level]);
281 struct btrfs_key cpukey;
282 u32 nritems = btrfs_header_nritems(&node->header);
284 if (path->nodes[level + 1])
285 parent = btrfs_buffer_node(path->nodes[level + 1]);
287 slot = path->slots[level];
288 BUG_ON(nritems == 0);
290 struct btrfs_disk_key *parent_key;
292 parent_slot = path->slots[level + 1];
293 parent_key = &parent->ptrs[parent_slot].key;
294 BUG_ON(memcmp(parent_key, &node->ptrs[0].key,
295 sizeof(struct btrfs_disk_key)));
296 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
297 btrfs_header_blocknr(&node->header));
299 BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
301 btrfs_disk_key_to_cpu(&cpukey, &node->ptrs[slot - 1].key);
302 BUG_ON(comp_keys(&node->ptrs[slot].key, &cpukey) <= 0);
304 if (slot < nritems - 1) {
305 btrfs_disk_key_to_cpu(&cpukey, &node->ptrs[slot + 1].key);
306 BUG_ON(comp_keys(&node->ptrs[slot].key, &cpukey) >= 0);
311 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
314 struct btrfs_leaf *leaf = btrfs_buffer_leaf(path->nodes[level]);
315 struct btrfs_node *parent = NULL;
317 int slot = path->slots[0];
318 struct btrfs_key cpukey;
320 u32 nritems = btrfs_header_nritems(&leaf->header);
322 if (path->nodes[level + 1])
323 parent = btrfs_buffer_node(path->nodes[level + 1]);
325 BUG_ON(btrfs_leaf_free_space(root, leaf) < 0);
331 struct btrfs_disk_key *parent_key;
333 parent_slot = path->slots[level + 1];
334 parent_key = &parent->ptrs[parent_slot].key;
336 BUG_ON(memcmp(parent_key, &leaf->items[0].key,
337 sizeof(struct btrfs_disk_key)));
338 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
339 btrfs_header_blocknr(&leaf->header));
342 btrfs_disk_key_to_cpu(&cpukey, &leaf->items[slot - 1].key);
343 BUG_ON(comp_keys(&leaf->items[slot].key, &cpukey) <= 0);
344 BUG_ON(btrfs_item_offset(leaf->items + slot - 1) !=
345 btrfs_item_end(leaf->items + slot));
347 if (slot < nritems - 1) {
348 btrfs_disk_key_to_cpu(&cpukey, &leaf->items[slot + 1].key);
349 BUG_ON(comp_keys(&leaf->items[slot].key, &cpukey) >= 0);
350 BUG_ON(btrfs_item_offset(leaf->items + slot) !=
351 btrfs_item_end(leaf->items + slot + 1));
353 BUG_ON(btrfs_item_offset(leaf->items) +
354 btrfs_item_size(leaf->items) != BTRFS_LEAF_DATA_SIZE(root));
358 static int check_block(struct btrfs_root *root, struct btrfs_path *path,
361 struct btrfs_node *node = btrfs_buffer_node(path->nodes[level]);
362 if (memcmp(node->header.fsid, root->fs_info->disk_super->fsid,
363 sizeof(node->header.fsid)))
366 return check_leaf(root, path, level);
367 return check_node(root, path, level);
371 * search for key in the array p. items p are item_size apart
372 * and there are 'max' items in p
373 * the slot in the array is returned via slot, and it points to
374 * the place where you would insert key if it is not found in
377 * slot may point to max if the key is bigger than all of the keys
379 static int generic_bin_search(char *p, int item_size, struct btrfs_key *key,
386 struct btrfs_disk_key *tmp;
389 mid = (low + high) / 2;
390 tmp = (struct btrfs_disk_key *)(p + mid * item_size);
391 ret = comp_keys(tmp, key);
407 * simple bin_search frontend that does the right thing for
410 static int bin_search(struct btrfs_node *c, struct btrfs_key *key, int *slot)
412 if (btrfs_is_leaf(c)) {
413 struct btrfs_leaf *l = (struct btrfs_leaf *)c;
414 return generic_bin_search((void *)l->items,
415 sizeof(struct btrfs_item),
416 key, btrfs_header_nritems(&c->header),
419 return generic_bin_search((void *)c->ptrs,
420 sizeof(struct btrfs_key_ptr),
421 key, btrfs_header_nritems(&c->header),
427 static struct buffer_head *read_node_slot(struct btrfs_root *root,
428 struct buffer_head *parent_buf,
431 struct btrfs_node *node = btrfs_buffer_node(parent_buf);
434 if (slot >= btrfs_header_nritems(&node->header))
436 return read_tree_block(root, btrfs_node_blockptr(node, slot));
439 static int balance_level(struct btrfs_trans_handle *trans, struct btrfs_root
440 *root, struct btrfs_path *path, int level)
442 struct buffer_head *right_buf;
443 struct buffer_head *mid_buf;
444 struct buffer_head *left_buf;
445 struct buffer_head *parent_buf = NULL;
446 struct btrfs_node *right = NULL;
447 struct btrfs_node *mid;
448 struct btrfs_node *left = NULL;
449 struct btrfs_node *parent = NULL;
453 int orig_slot = path->slots[level];
454 int err_on_enospc = 0;
460 mid_buf = path->nodes[level];
461 mid = btrfs_buffer_node(mid_buf);
462 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
464 if (level < BTRFS_MAX_LEVEL - 1)
465 parent_buf = path->nodes[level + 1];
466 pslot = path->slots[level + 1];
469 * deal with the case where there is only one pointer in the root
470 * by promoting the node below to a root
473 struct buffer_head *child;
474 u64 blocknr = bh_blocknr(mid_buf);
476 if (btrfs_header_nritems(&mid->header) != 1)
479 /* promote the child to a root */
480 child = read_node_slot(root, mid_buf, 0);
483 path->nodes[level] = NULL;
484 clean_tree_block(trans, root, mid_buf);
485 wait_on_buffer(mid_buf);
486 /* once for the path */
487 btrfs_block_release(root, mid_buf);
488 /* once for the root ptr */
489 btrfs_block_release(root, mid_buf);
490 return btrfs_free_extent(trans, root, blocknr, 1, 1);
492 parent = btrfs_buffer_node(parent_buf);
494 if (btrfs_header_nritems(&mid->header) >
495 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
498 if (btrfs_header_nritems(&mid->header) < 2)
501 left_buf = read_node_slot(root, parent_buf, pslot - 1);
502 right_buf = read_node_slot(root, parent_buf, pslot + 1);
504 /* first, try to make some room in the middle buffer */
506 wret = btrfs_cow_block(trans, root, left_buf,
507 parent_buf, pslot - 1, &left_buf);
512 left = btrfs_buffer_node(left_buf);
513 orig_slot += btrfs_header_nritems(&left->header);
514 wret = push_node_left(trans, root, left_buf, mid_buf);
517 if (btrfs_header_nritems(&mid->header) < 2)
522 * then try to empty the right most buffer into the middle
525 wret = btrfs_cow_block(trans, root, right_buf,
526 parent_buf, pslot + 1, &right_buf);
532 right = btrfs_buffer_node(right_buf);
533 wret = push_node_left(trans, root, mid_buf, right_buf);
534 if (wret < 0 && wret != -ENOSPC)
536 if (btrfs_header_nritems(&right->header) == 0) {
537 u64 blocknr = bh_blocknr(right_buf);
538 clean_tree_block(trans, root, right_buf);
539 wait_on_buffer(right_buf);
540 btrfs_block_release(root, right_buf);
543 wret = del_ptr(trans, root, path, level + 1, pslot +
547 wret = btrfs_free_extent(trans, root, blocknr, 1, 1);
551 btrfs_memcpy(root, parent,
552 &parent->ptrs[pslot + 1].key,
554 sizeof(struct btrfs_disk_key));
555 btrfs_mark_buffer_dirty(parent_buf);
558 if (btrfs_header_nritems(&mid->header) == 1) {
560 * we're not allowed to leave a node with one item in the
561 * tree during a delete. A deletion from lower in the tree
562 * could try to delete the only pointer in this node.
563 * So, pull some keys from the left.
564 * There has to be a left pointer at this point because
565 * otherwise we would have pulled some pointers from the
569 wret = balance_node_right(trans, root, mid_buf, left_buf);
576 if (btrfs_header_nritems(&mid->header) == 0) {
577 /* we've managed to empty the middle node, drop it */
578 u64 blocknr = bh_blocknr(mid_buf);
579 clean_tree_block(trans, root, mid_buf);
580 wait_on_buffer(mid_buf);
581 btrfs_block_release(root, mid_buf);
584 wret = del_ptr(trans, root, path, level + 1, pslot);
587 wret = btrfs_free_extent(trans, root, blocknr, 1, 1);
591 /* update the parent key to reflect our changes */
592 btrfs_memcpy(root, parent,
593 &parent->ptrs[pslot].key, &mid->ptrs[0].key,
594 sizeof(struct btrfs_disk_key));
595 btrfs_mark_buffer_dirty(parent_buf);
598 /* update the path */
600 if (btrfs_header_nritems(&left->header) > orig_slot) {
602 path->nodes[level] = left_buf;
603 path->slots[level + 1] -= 1;
604 path->slots[level] = orig_slot;
606 btrfs_block_release(root, mid_buf);
608 orig_slot -= btrfs_header_nritems(&left->header);
609 path->slots[level] = orig_slot;
612 /* double check we haven't messed things up */
613 check_block(root, path, level);
615 btrfs_node_blockptr(btrfs_buffer_node(path->nodes[level]),
620 btrfs_block_release(root, right_buf);
622 btrfs_block_release(root, left_buf);
626 /* returns zero if the push worked, non-zero otherwise */
627 static int push_nodes_for_insert(struct btrfs_trans_handle *trans,
628 struct btrfs_root *root,
629 struct btrfs_path *path, int level)
631 struct buffer_head *right_buf;
632 struct buffer_head *mid_buf;
633 struct buffer_head *left_buf;
634 struct buffer_head *parent_buf = NULL;
635 struct btrfs_node *right = NULL;
636 struct btrfs_node *mid;
637 struct btrfs_node *left = NULL;
638 struct btrfs_node *parent = NULL;
642 int orig_slot = path->slots[level];
648 mid_buf = path->nodes[level];
649 mid = btrfs_buffer_node(mid_buf);
650 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
652 if (level < BTRFS_MAX_LEVEL - 1)
653 parent_buf = path->nodes[level + 1];
654 pslot = path->slots[level + 1];
658 parent = btrfs_buffer_node(parent_buf);
660 left_buf = read_node_slot(root, parent_buf, pslot - 1);
662 /* first, try to make some room in the middle buffer */
665 left = btrfs_buffer_node(left_buf);
666 left_nr = btrfs_header_nritems(&left->header);
667 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
670 ret = btrfs_cow_block(trans, root, left_buf, parent_buf,
671 pslot - 1, &left_buf);
675 left = btrfs_buffer_node(left_buf);
676 wret = push_node_left(trans, root,
683 orig_slot += left_nr;
684 btrfs_memcpy(root, parent,
685 &parent->ptrs[pslot].key,
687 sizeof(struct btrfs_disk_key));
688 btrfs_mark_buffer_dirty(parent_buf);
689 if (btrfs_header_nritems(&left->header) > orig_slot) {
690 path->nodes[level] = left_buf;
691 path->slots[level + 1] -= 1;
692 path->slots[level] = orig_slot;
693 btrfs_block_release(root, mid_buf);
696 btrfs_header_nritems(&left->header);
697 path->slots[level] = orig_slot;
698 btrfs_block_release(root, left_buf);
700 check_node(root, path, level);
703 btrfs_block_release(root, left_buf);
705 right_buf = read_node_slot(root, parent_buf, pslot + 1);
708 * then try to empty the right most buffer into the middle
712 right = btrfs_buffer_node(right_buf);
713 right_nr = btrfs_header_nritems(&right->header);
714 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
717 ret = btrfs_cow_block(trans, root, right_buf,
718 parent_buf, pslot + 1,
723 right = btrfs_buffer_node(right_buf);
724 wret = balance_node_right(trans, root,
731 btrfs_memcpy(root, parent,
732 &parent->ptrs[pslot + 1].key,
734 sizeof(struct btrfs_disk_key));
735 btrfs_mark_buffer_dirty(parent_buf);
736 if (btrfs_header_nritems(&mid->header) <= orig_slot) {
737 path->nodes[level] = right_buf;
738 path->slots[level + 1] += 1;
739 path->slots[level] = orig_slot -
740 btrfs_header_nritems(&mid->header);
741 btrfs_block_release(root, mid_buf);
743 btrfs_block_release(root, right_buf);
745 check_node(root, path, level);
748 btrfs_block_release(root, right_buf);
750 check_node(root, path, level);
755 * readahead one full node of leaves
757 static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
760 struct btrfs_node *node;
769 int direction = path->reada;
770 struct radix_tree_root found;
771 unsigned long gang[8];
772 struct buffer_head *bh;
777 if (!path->nodes[level])
780 node = btrfs_buffer_node(path->nodes[level]);
781 search = btrfs_node_blockptr(node, slot);
782 bh = btrfs_find_tree_block(root, search);
788 init_bit_radix(&found);
789 nritems = btrfs_header_nritems(&node->header);
790 for (i = slot; i < nritems; i++) {
791 item_objectid = btrfs_disk_key_objectid(&node->ptrs[i].key);
792 blocknr = btrfs_node_blockptr(node, i);
793 set_radix_bit(&found, blocknr);
796 cluster_start = search - 4;
797 if (cluster_start > search)
800 cluster_start = search + 4;
802 ret = find_first_radix_bit(&found, gang, 0, ARRAY_SIZE(gang));
805 for (i = 0; i < ret; i++) {
807 clear_radix_bit(&found, blocknr);
810 if (direction > 0 && cluster_start <= blocknr &&
811 cluster_start + 8 > blocknr) {
812 cluster_start = blocknr;
813 readahead_tree_block(root, blocknr);
815 } else if (direction < 0 && cluster_start >= blocknr &&
816 blocknr + 8 > cluster_start) {
817 cluster_start = blocknr;
818 readahead_tree_block(root, blocknr);
825 * look for key in the tree. path is filled in with nodes along the way
826 * if key is found, we return zero and you can find the item in the leaf
827 * level of the path (level 0)
829 * If the key isn't found, the path points to the slot where it should
830 * be inserted, and 1 is returned. If there are other errors during the
831 * search a negative error number is returned.
833 * if ins_len > 0, nodes and leaves will be split as we walk down the
834 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
837 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
838 *root, struct btrfs_key *key, struct btrfs_path *p, int
841 struct buffer_head *b;
842 struct buffer_head *cow_buf;
843 struct btrfs_node *c;
848 int should_reada = p->reada;
851 lowest_level = p->lowest_level;
852 WARN_ON(lowest_level && ins_len);
853 WARN_ON(p->nodes[0] != NULL);
854 WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
859 c = btrfs_buffer_node(b);
860 level = btrfs_header_level(&c->header);
863 wret = btrfs_cow_block(trans, root, b,
868 btrfs_block_release(root, cow_buf);
872 c = btrfs_buffer_node(b);
874 BUG_ON(!cow && ins_len);
875 if (level != btrfs_header_level(&c->header))
877 level = btrfs_header_level(&c->header);
879 ret = check_block(root, p, level);
882 ret = bin_search(c, key, &slot);
883 if (!btrfs_is_leaf(c)) {
886 p->slots[level] = slot;
887 if (ins_len > 0 && btrfs_header_nritems(&c->header) >=
888 BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
889 int sret = split_node(trans, root, p, level);
894 c = btrfs_buffer_node(b);
895 slot = p->slots[level];
896 } else if (ins_len < 0) {
897 int sret = balance_level(trans, root, p,
904 c = btrfs_buffer_node(b);
905 slot = p->slots[level];
906 BUG_ON(btrfs_header_nritems(&c->header) == 1);
908 /* this is only true while dropping a snapshot */
909 if (level == lowest_level)
911 blocknr = btrfs_node_blockptr(c, slot);
913 reada_for_search(root, p, level, slot);
914 b = read_tree_block(root, btrfs_node_blockptr(c, slot));
917 struct btrfs_leaf *l = (struct btrfs_leaf *)c;
918 p->slots[level] = slot;
919 if (ins_len > 0 && btrfs_leaf_free_space(root, l) <
920 sizeof(struct btrfs_item) + ins_len) {
921 int sret = split_leaf(trans, root, key,
934 * adjust the pointers going up the tree, starting at level
935 * making sure the right key of each node is points to 'key'.
936 * This is used after shifting pointers to the left, so it stops
937 * fixing up pointers when a given leaf/node is not in slot 0 of the
940 * If this fails to write a tree block, it returns -1, but continues
941 * fixing up the blocks in ram so the tree is consistent.
943 static int fixup_low_keys(struct btrfs_trans_handle *trans, struct btrfs_root
944 *root, struct btrfs_path *path, struct btrfs_disk_key
949 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
950 struct btrfs_node *t;
951 int tslot = path->slots[i];
954 t = btrfs_buffer_node(path->nodes[i]);
955 btrfs_memcpy(root, t, &t->ptrs[tslot].key, key, sizeof(*key));
956 btrfs_mark_buffer_dirty(path->nodes[i]);
964 * try to push data from one node into the next node left in the
967 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
968 * error, and > 0 if there was no room in the left hand block.
970 static int push_node_left(struct btrfs_trans_handle *trans, struct btrfs_root
971 *root, struct buffer_head *dst_buf, struct
972 buffer_head *src_buf)
974 struct btrfs_node *src = btrfs_buffer_node(src_buf);
975 struct btrfs_node *dst = btrfs_buffer_node(dst_buf);
981 src_nritems = btrfs_header_nritems(&src->header);
982 dst_nritems = btrfs_header_nritems(&dst->header);
983 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
985 if (push_items <= 0) {
989 if (src_nritems < push_items)
990 push_items = src_nritems;
992 btrfs_memcpy(root, dst, dst->ptrs + dst_nritems, src->ptrs,
993 push_items * sizeof(struct btrfs_key_ptr));
994 if (push_items < src_nritems) {
995 btrfs_memmove(root, src, src->ptrs, src->ptrs + push_items,
996 (src_nritems - push_items) *
997 sizeof(struct btrfs_key_ptr));
999 btrfs_set_header_nritems(&src->header, src_nritems - push_items);
1000 btrfs_set_header_nritems(&dst->header, dst_nritems + push_items);
1001 btrfs_mark_buffer_dirty(src_buf);
1002 btrfs_mark_buffer_dirty(dst_buf);
1007 * try to push data from one node into the next node right in the
1010 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1011 * error, and > 0 if there was no room in the right hand block.
1013 * this will only push up to 1/2 the contents of the left node over
1015 static int balance_node_right(struct btrfs_trans_handle *trans, struct
1016 btrfs_root *root, struct buffer_head *dst_buf,
1017 struct buffer_head *src_buf)
1019 struct btrfs_node *src = btrfs_buffer_node(src_buf);
1020 struct btrfs_node *dst = btrfs_buffer_node(dst_buf);
1027 src_nritems = btrfs_header_nritems(&src->header);
1028 dst_nritems = btrfs_header_nritems(&dst->header);
1029 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1030 if (push_items <= 0) {
1034 max_push = src_nritems / 2 + 1;
1035 /* don't try to empty the node */
1036 if (max_push > src_nritems)
1038 if (max_push < push_items)
1039 push_items = max_push;
1041 btrfs_memmove(root, dst, dst->ptrs + push_items, dst->ptrs,
1042 dst_nritems * sizeof(struct btrfs_key_ptr));
1044 btrfs_memcpy(root, dst, dst->ptrs,
1045 src->ptrs + src_nritems - push_items,
1046 push_items * sizeof(struct btrfs_key_ptr));
1048 btrfs_set_header_nritems(&src->header, src_nritems - push_items);
1049 btrfs_set_header_nritems(&dst->header, dst_nritems + push_items);
1051 btrfs_mark_buffer_dirty(src_buf);
1052 btrfs_mark_buffer_dirty(dst_buf);
1057 * helper function to insert a new root level in the tree.
1058 * A new node is allocated, and a single item is inserted to
1059 * point to the existing root
1061 * returns zero on success or < 0 on failure.
1063 static int insert_new_root(struct btrfs_trans_handle *trans, struct btrfs_root
1064 *root, struct btrfs_path *path, int level)
1066 struct buffer_head *t;
1067 struct btrfs_node *lower;
1068 struct btrfs_node *c;
1069 struct btrfs_disk_key *lower_key;
1071 BUG_ON(path->nodes[level]);
1072 BUG_ON(path->nodes[level-1] != root->node);
1074 t = btrfs_alloc_free_block(trans, root, root->node->b_blocknr, 0);
1077 c = btrfs_buffer_node(t);
1078 memset(c, 0, root->blocksize);
1079 btrfs_set_header_nritems(&c->header, 1);
1080 btrfs_set_header_level(&c->header, level);
1081 btrfs_set_header_blocknr(&c->header, bh_blocknr(t));
1082 btrfs_set_header_generation(&c->header, trans->transid);
1083 btrfs_set_header_owner(&c->header, root->root_key.objectid);
1084 lower = btrfs_buffer_node(path->nodes[level-1]);
1085 memcpy(c->header.fsid, root->fs_info->disk_super->fsid,
1086 sizeof(c->header.fsid));
1087 if (btrfs_is_leaf(lower))
1088 lower_key = &((struct btrfs_leaf *)lower)->items[0].key;
1090 lower_key = &lower->ptrs[0].key;
1091 btrfs_memcpy(root, c, &c->ptrs[0].key, lower_key,
1092 sizeof(struct btrfs_disk_key));
1093 btrfs_set_node_blockptr(c, 0, bh_blocknr(path->nodes[level - 1]));
1095 btrfs_mark_buffer_dirty(t);
1097 /* the super has an extra ref to root->node */
1098 btrfs_block_release(root, root->node);
1101 path->nodes[level] = t;
1102 path->slots[level] = 0;
1107 * worker function to insert a single pointer in a node.
1108 * the node should have enough room for the pointer already
1110 * slot and level indicate where you want the key to go, and
1111 * blocknr is the block the key points to.
1113 * returns zero on success and < 0 on any error
1115 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1116 *root, struct btrfs_path *path, struct btrfs_disk_key
1117 *key, u64 blocknr, int slot, int level)
1119 struct btrfs_node *lower;
1122 BUG_ON(!path->nodes[level]);
1123 lower = btrfs_buffer_node(path->nodes[level]);
1124 nritems = btrfs_header_nritems(&lower->header);
1127 if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1129 if (slot != nritems) {
1130 btrfs_memmove(root, lower, lower->ptrs + slot + 1,
1132 (nritems - slot) * sizeof(struct btrfs_key_ptr));
1134 btrfs_memcpy(root, lower, &lower->ptrs[slot].key,
1135 key, sizeof(struct btrfs_disk_key));
1136 btrfs_set_node_blockptr(lower, slot, blocknr);
1137 btrfs_set_header_nritems(&lower->header, nritems + 1);
1138 btrfs_mark_buffer_dirty(path->nodes[level]);
1139 check_node(root, path, level);
1144 * split the node at the specified level in path in two.
1145 * The path is corrected to point to the appropriate node after the split
1147 * Before splitting this tries to make some room in the node by pushing
1148 * left and right, if either one works, it returns right away.
1150 * returns 0 on success and < 0 on failure
1152 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1153 *root, struct btrfs_path *path, int level)
1155 struct buffer_head *t;
1156 struct btrfs_node *c;
1157 struct buffer_head *split_buffer;
1158 struct btrfs_node *split;
1164 t = path->nodes[level];
1165 c = btrfs_buffer_node(t);
1166 if (t == root->node) {
1167 /* trying to split the root, lets make a new one */
1168 ret = insert_new_root(trans, root, path, level + 1);
1172 ret = push_nodes_for_insert(trans, root, path, level);
1173 t = path->nodes[level];
1174 c = btrfs_buffer_node(t);
1176 btrfs_header_nritems(&c->header) <
1177 BTRFS_NODEPTRS_PER_BLOCK(root) - 1)
1183 c_nritems = btrfs_header_nritems(&c->header);
1184 split_buffer = btrfs_alloc_free_block(trans, root, t->b_blocknr, 0);
1185 if (IS_ERR(split_buffer))
1186 return PTR_ERR(split_buffer);
1188 split = btrfs_buffer_node(split_buffer);
1189 btrfs_set_header_flags(&split->header, btrfs_header_flags(&c->header));
1190 btrfs_set_header_level(&split->header, btrfs_header_level(&c->header));
1191 btrfs_set_header_blocknr(&split->header, bh_blocknr(split_buffer));
1192 btrfs_set_header_generation(&split->header, trans->transid);
1193 btrfs_set_header_owner(&split->header, root->root_key.objectid);
1194 memcpy(split->header.fsid, root->fs_info->disk_super->fsid,
1195 sizeof(split->header.fsid));
1196 mid = (c_nritems + 1) / 2;
1197 btrfs_memcpy(root, split, split->ptrs, c->ptrs + mid,
1198 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1199 btrfs_set_header_nritems(&split->header, c_nritems - mid);
1200 btrfs_set_header_nritems(&c->header, mid);
1203 btrfs_mark_buffer_dirty(t);
1204 btrfs_mark_buffer_dirty(split_buffer);
1205 wret = insert_ptr(trans, root, path, &split->ptrs[0].key,
1206 bh_blocknr(split_buffer), path->slots[level + 1] + 1,
1211 if (path->slots[level] >= mid) {
1212 path->slots[level] -= mid;
1213 btrfs_block_release(root, t);
1214 path->nodes[level] = split_buffer;
1215 path->slots[level + 1] += 1;
1217 btrfs_block_release(root, split_buffer);
1223 * how many bytes are required to store the items in a leaf. start
1224 * and nr indicate which items in the leaf to check. This totals up the
1225 * space used both by the item structs and the item data
1227 static int leaf_space_used(struct btrfs_leaf *l, int start, int nr)
1230 int nritems = btrfs_header_nritems(&l->header);
1231 int end = min(nritems, start + nr) - 1;
1235 data_len = btrfs_item_end(l->items + start);
1236 data_len = data_len - btrfs_item_offset(l->items + end);
1237 data_len += sizeof(struct btrfs_item) * nr;
1238 WARN_ON(data_len < 0);
1243 * The space between the end of the leaf items and
1244 * the start of the leaf data. IOW, how much room
1245 * the leaf has left for both items and data
1247 int btrfs_leaf_free_space(struct btrfs_root *root, struct btrfs_leaf *leaf)
1249 int nritems = btrfs_header_nritems(&leaf->header);
1250 return BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
1254 * push some data in the path leaf to the right, trying to free up at
1255 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1257 * returns 1 if the push failed because the other node didn't have enough
1258 * room, 0 if everything worked out and < 0 if there were major errors.
1260 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1261 *root, struct btrfs_path *path, int data_size)
1263 struct buffer_head *left_buf = path->nodes[0];
1264 struct btrfs_leaf *left = btrfs_buffer_leaf(left_buf);
1265 struct btrfs_leaf *right;
1266 struct buffer_head *right_buf;
1267 struct buffer_head *upper;
1268 struct btrfs_node *upper_node;
1274 struct btrfs_item *item;
1279 slot = path->slots[1];
1280 if (!path->nodes[1]) {
1283 upper = path->nodes[1];
1284 upper_node = btrfs_buffer_node(upper);
1285 if (slot >= btrfs_header_nritems(&upper_node->header) - 1) {
1288 right_buf = read_tree_block(root,
1289 btrfs_node_blockptr(btrfs_buffer_node(upper), slot + 1));
1290 right = btrfs_buffer_leaf(right_buf);
1291 free_space = btrfs_leaf_free_space(root, right);
1292 if (free_space < data_size + sizeof(struct btrfs_item)) {
1293 btrfs_block_release(root, right_buf);
1296 /* cow and double check */
1297 ret = btrfs_cow_block(trans, root, right_buf, upper,
1298 slot + 1, &right_buf);
1300 btrfs_block_release(root, right_buf);
1303 right = btrfs_buffer_leaf(right_buf);
1304 free_space = btrfs_leaf_free_space(root, right);
1305 if (free_space < data_size + sizeof(struct btrfs_item)) {
1306 btrfs_block_release(root, right_buf);
1310 left_nritems = btrfs_header_nritems(&left->header);
1311 if (left_nritems == 0) {
1312 btrfs_block_release(root, right_buf);
1315 for (i = left_nritems - 1; i >= 1; i--) {
1316 item = left->items + i;
1317 if (path->slots[0] == i)
1318 push_space += data_size + sizeof(*item);
1319 if (btrfs_item_size(item) + sizeof(*item) + push_space >
1323 push_space += btrfs_item_size(item) + sizeof(*item);
1325 if (push_items == 0) {
1326 btrfs_block_release(root, right_buf);
1329 if (push_items == left_nritems)
1331 right_nritems = btrfs_header_nritems(&right->header);
1332 /* push left to right */
1333 push_space = btrfs_item_end(left->items + left_nritems - push_items);
1334 push_space -= leaf_data_end(root, left);
1335 /* make room in the right data area */
1336 btrfs_memmove(root, right, btrfs_leaf_data(right) +
1337 leaf_data_end(root, right) - push_space,
1338 btrfs_leaf_data(right) +
1339 leaf_data_end(root, right), BTRFS_LEAF_DATA_SIZE(root) -
1340 leaf_data_end(root, right));
1341 /* copy from the left data area */
1342 btrfs_memcpy(root, right, btrfs_leaf_data(right) +
1343 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1344 btrfs_leaf_data(left) + leaf_data_end(root, left),
1346 btrfs_memmove(root, right, right->items + push_items, right->items,
1347 right_nritems * sizeof(struct btrfs_item));
1348 /* copy the items from left to right */
1349 btrfs_memcpy(root, right, right->items, left->items +
1350 left_nritems - push_items,
1351 push_items * sizeof(struct btrfs_item));
1353 /* update the item pointers */
1354 right_nritems += push_items;
1355 btrfs_set_header_nritems(&right->header, right_nritems);
1356 push_space = BTRFS_LEAF_DATA_SIZE(root);
1357 for (i = 0; i < right_nritems; i++) {
1358 btrfs_set_item_offset(right->items + i, push_space -
1359 btrfs_item_size(right->items + i));
1360 push_space = btrfs_item_offset(right->items + i);
1362 left_nritems -= push_items;
1363 btrfs_set_header_nritems(&left->header, left_nritems);
1365 btrfs_mark_buffer_dirty(left_buf);
1366 btrfs_mark_buffer_dirty(right_buf);
1368 btrfs_memcpy(root, upper_node, &upper_node->ptrs[slot + 1].key,
1369 &right->items[0].key, sizeof(struct btrfs_disk_key));
1370 btrfs_mark_buffer_dirty(upper);
1372 /* then fixup the leaf pointer in the path */
1373 if (path->slots[0] >= left_nritems) {
1374 path->slots[0] -= left_nritems;
1375 btrfs_block_release(root, path->nodes[0]);
1376 path->nodes[0] = right_buf;
1377 path->slots[1] += 1;
1379 btrfs_block_release(root, right_buf);
1382 check_node(root, path, 1);
1386 * push some data in the path leaf to the left, trying to free up at
1387 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1389 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1390 *root, struct btrfs_path *path, int data_size)
1392 struct buffer_head *right_buf = path->nodes[0];
1393 struct btrfs_leaf *right = btrfs_buffer_leaf(right_buf);
1394 struct buffer_head *t;
1395 struct btrfs_leaf *left;
1401 struct btrfs_item *item;
1402 u32 old_left_nritems;
1406 slot = path->slots[1];
1410 if (!path->nodes[1]) {
1413 t = read_tree_block(root,
1414 btrfs_node_blockptr(btrfs_buffer_node(path->nodes[1]), slot - 1));
1415 left = btrfs_buffer_leaf(t);
1416 free_space = btrfs_leaf_free_space(root, left);
1417 if (free_space < data_size + sizeof(struct btrfs_item)) {
1418 btrfs_block_release(root, t);
1422 /* cow and double check */
1423 ret = btrfs_cow_block(trans, root, t, path->nodes[1], slot - 1, &t);
1425 /* we hit -ENOSPC, but it isn't fatal here */
1428 left = btrfs_buffer_leaf(t);
1429 free_space = btrfs_leaf_free_space(root, left);
1430 if (free_space < data_size + sizeof(struct btrfs_item)) {
1431 btrfs_block_release(root, t);
1435 if (btrfs_header_nritems(&right->header) == 0) {
1436 btrfs_block_release(root, t);
1440 for (i = 0; i < btrfs_header_nritems(&right->header) - 1; i++) {
1441 item = right->items + i;
1442 if (path->slots[0] == i)
1443 push_space += data_size + sizeof(*item);
1444 if (btrfs_item_size(item) + sizeof(*item) + push_space >
1448 push_space += btrfs_item_size(item) + sizeof(*item);
1450 if (push_items == 0) {
1451 btrfs_block_release(root, t);
1454 if (push_items == btrfs_header_nritems(&right->header))
1456 /* push data from right to left */
1457 btrfs_memcpy(root, left, left->items +
1458 btrfs_header_nritems(&left->header),
1459 right->items, push_items * sizeof(struct btrfs_item));
1460 push_space = BTRFS_LEAF_DATA_SIZE(root) -
1461 btrfs_item_offset(right->items + push_items -1);
1462 btrfs_memcpy(root, left, btrfs_leaf_data(left) +
1463 leaf_data_end(root, left) - push_space,
1464 btrfs_leaf_data(right) +
1465 btrfs_item_offset(right->items + push_items - 1),
1467 old_left_nritems = btrfs_header_nritems(&left->header);
1468 BUG_ON(old_left_nritems < 0);
1470 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1471 u32 ioff = btrfs_item_offset(left->items + i);
1472 btrfs_set_item_offset(left->items + i, ioff -
1473 (BTRFS_LEAF_DATA_SIZE(root) -
1474 btrfs_item_offset(left->items +
1475 old_left_nritems - 1)));
1477 btrfs_set_header_nritems(&left->header, old_left_nritems + push_items);
1479 /* fixup right node */
1480 push_space = btrfs_item_offset(right->items + push_items - 1) -
1481 leaf_data_end(root, right);
1482 btrfs_memmove(root, right, btrfs_leaf_data(right) +
1483 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1484 btrfs_leaf_data(right) +
1485 leaf_data_end(root, right), push_space);
1486 btrfs_memmove(root, right, right->items, right->items + push_items,
1487 (btrfs_header_nritems(&right->header) - push_items) *
1488 sizeof(struct btrfs_item));
1489 btrfs_set_header_nritems(&right->header,
1490 btrfs_header_nritems(&right->header) -
1492 push_space = BTRFS_LEAF_DATA_SIZE(root);
1494 for (i = 0; i < btrfs_header_nritems(&right->header); i++) {
1495 btrfs_set_item_offset(right->items + i, push_space -
1496 btrfs_item_size(right->items + i));
1497 push_space = btrfs_item_offset(right->items + i);
1500 btrfs_mark_buffer_dirty(t);
1501 btrfs_mark_buffer_dirty(right_buf);
1503 wret = fixup_low_keys(trans, root, path, &right->items[0].key, 1);
1507 /* then fixup the leaf pointer in the path */
1508 if (path->slots[0] < push_items) {
1509 path->slots[0] += old_left_nritems;
1510 btrfs_block_release(root, path->nodes[0]);
1512 path->slots[1] -= 1;
1514 btrfs_block_release(root, t);
1515 path->slots[0] -= push_items;
1517 BUG_ON(path->slots[0] < 0);
1519 check_node(root, path, 1);
1524 * split the path's leaf in two, making sure there is at least data_size
1525 * available for the resulting leaf level of the path.
1527 * returns 0 if all went well and < 0 on failure.
1529 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
1530 *root, struct btrfs_key *ins_key,
1531 struct btrfs_path *path, int data_size)
1533 struct buffer_head *l_buf;
1534 struct btrfs_leaf *l;
1538 struct btrfs_leaf *right;
1539 struct buffer_head *right_buffer;
1540 int space_needed = data_size + sizeof(struct btrfs_item);
1546 int double_split = 0;
1547 struct btrfs_disk_key disk_key;
1549 /* first try to make some room by pushing left and right */
1550 wret = push_leaf_left(trans, root, path, data_size);
1554 wret = push_leaf_right(trans, root, path, data_size);
1558 l_buf = path->nodes[0];
1559 l = btrfs_buffer_leaf(l_buf);
1561 /* did the pushes work? */
1562 if (btrfs_leaf_free_space(root, l) >=
1563 sizeof(struct btrfs_item) + data_size)
1566 if (!path->nodes[1]) {
1567 ret = insert_new_root(trans, root, path, 1);
1571 slot = path->slots[0];
1572 nritems = btrfs_header_nritems(&l->header);
1573 mid = (nritems + 1)/ 2;
1575 right_buffer = btrfs_alloc_free_block(trans, root, l_buf->b_blocknr, 0);
1576 if (IS_ERR(right_buffer))
1577 return PTR_ERR(right_buffer);
1579 right = btrfs_buffer_leaf(right_buffer);
1580 memset(&right->header, 0, sizeof(right->header));
1581 btrfs_set_header_blocknr(&right->header, bh_blocknr(right_buffer));
1582 btrfs_set_header_generation(&right->header, trans->transid);
1583 btrfs_set_header_owner(&right->header, root->root_key.objectid);
1584 btrfs_set_header_level(&right->header, 0);
1585 memcpy(right->header.fsid, root->fs_info->disk_super->fsid,
1586 sizeof(right->header.fsid));
1589 leaf_space_used(l, mid, nritems - mid) + space_needed >
1590 BTRFS_LEAF_DATA_SIZE(root)) {
1591 if (slot >= nritems) {
1592 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1593 btrfs_set_header_nritems(&right->header, 0);
1594 wret = insert_ptr(trans, root, path,
1596 bh_blocknr(right_buffer),
1597 path->slots[1] + 1, 1);
1600 btrfs_block_release(root, path->nodes[0]);
1601 path->nodes[0] = right_buffer;
1603 path->slots[1] += 1;
1610 if (leaf_space_used(l, 0, mid + 1) + space_needed >
1611 BTRFS_LEAF_DATA_SIZE(root)) {
1613 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1614 btrfs_set_header_nritems(&right->header, 0);
1615 wret = insert_ptr(trans, root, path,
1617 bh_blocknr(right_buffer),
1621 btrfs_block_release(root, path->nodes[0]);
1622 path->nodes[0] = right_buffer;
1624 if (path->slots[1] == 0) {
1625 wret = fixup_low_keys(trans, root,
1626 path, &disk_key, 1);
1636 btrfs_set_header_nritems(&right->header, nritems - mid);
1637 data_copy_size = btrfs_item_end(l->items + mid) -
1638 leaf_data_end(root, l);
1639 btrfs_memcpy(root, right, right->items, l->items + mid,
1640 (nritems - mid) * sizeof(struct btrfs_item));
1641 btrfs_memcpy(root, right,
1642 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
1643 data_copy_size, btrfs_leaf_data(l) +
1644 leaf_data_end(root, l), data_copy_size);
1645 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
1646 btrfs_item_end(l->items + mid);
1648 for (i = 0; i < btrfs_header_nritems(&right->header); i++) {
1649 u32 ioff = btrfs_item_offset(right->items + i);
1650 btrfs_set_item_offset(right->items + i, ioff + rt_data_off);
1653 btrfs_set_header_nritems(&l->header, mid);
1655 wret = insert_ptr(trans, root, path, &right->items[0].key,
1656 bh_blocknr(right_buffer), path->slots[1] + 1, 1);
1659 btrfs_mark_buffer_dirty(right_buffer);
1660 btrfs_mark_buffer_dirty(l_buf);
1661 BUG_ON(path->slots[0] != slot);
1663 btrfs_block_release(root, path->nodes[0]);
1664 path->nodes[0] = right_buffer;
1665 path->slots[0] -= mid;
1666 path->slots[1] += 1;
1668 btrfs_block_release(root, right_buffer);
1669 BUG_ON(path->slots[0] < 0);
1670 check_node(root, path, 1);
1674 right_buffer = btrfs_alloc_free_block(trans, root, l_buf->b_blocknr, 0);
1675 if (IS_ERR(right_buffer))
1676 return PTR_ERR(right_buffer);
1678 right = btrfs_buffer_leaf(right_buffer);
1679 memset(&right->header, 0, sizeof(right->header));
1680 btrfs_set_header_blocknr(&right->header, bh_blocknr(right_buffer));
1681 btrfs_set_header_generation(&right->header, trans->transid);
1682 btrfs_set_header_owner(&right->header, root->root_key.objectid);
1683 btrfs_set_header_level(&right->header, 0);
1684 memcpy(right->header.fsid, root->fs_info->disk_super->fsid,
1685 sizeof(right->header.fsid));
1686 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1687 btrfs_set_header_nritems(&right->header, 0);
1688 wret = insert_ptr(trans, root, path,
1690 bh_blocknr(right_buffer),
1694 if (path->slots[1] == 0) {
1695 wret = fixup_low_keys(trans, root, path, &disk_key, 1);
1699 btrfs_block_release(root, path->nodes[0]);
1700 path->nodes[0] = right_buffer;
1702 check_node(root, path, 1);
1703 check_leaf(root, path, 0);
1707 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
1708 struct btrfs_root *root,
1709 struct btrfs_path *path,
1715 struct btrfs_leaf *leaf;
1716 struct buffer_head *leaf_buf;
1718 unsigned int data_end;
1719 unsigned int old_data_start;
1720 unsigned int old_size;
1721 unsigned int size_diff;
1724 slot_orig = path->slots[0];
1725 leaf_buf = path->nodes[0];
1726 leaf = btrfs_buffer_leaf(leaf_buf);
1728 nritems = btrfs_header_nritems(&leaf->header);
1729 data_end = leaf_data_end(root, leaf);
1731 slot = path->slots[0];
1732 old_data_start = btrfs_item_offset(leaf->items + slot);
1733 old_size = btrfs_item_size(leaf->items + slot);
1734 BUG_ON(old_size <= new_size);
1735 size_diff = old_size - new_size;
1738 BUG_ON(slot >= nritems);
1741 * item0..itemN ... dataN.offset..dataN.size .. data0.size
1743 /* first correct the data pointers */
1744 for (i = slot; i < nritems; i++) {
1745 u32 ioff = btrfs_item_offset(leaf->items + i);
1746 btrfs_set_item_offset(leaf->items + i,
1749 /* shift the data */
1750 btrfs_memmove(root, leaf, btrfs_leaf_data(leaf) +
1751 data_end + size_diff, btrfs_leaf_data(leaf) +
1752 data_end, old_data_start + new_size - data_end);
1753 btrfs_set_item_size(leaf->items + slot, new_size);
1754 btrfs_mark_buffer_dirty(leaf_buf);
1757 if (btrfs_leaf_free_space(root, leaf) < 0)
1759 check_leaf(root, path, 0);
1763 int btrfs_extend_item(struct btrfs_trans_handle *trans, struct btrfs_root
1764 *root, struct btrfs_path *path, u32 data_size)
1769 struct btrfs_leaf *leaf;
1770 struct buffer_head *leaf_buf;
1772 unsigned int data_end;
1773 unsigned int old_data;
1774 unsigned int old_size;
1777 slot_orig = path->slots[0];
1778 leaf_buf = path->nodes[0];
1779 leaf = btrfs_buffer_leaf(leaf_buf);
1781 nritems = btrfs_header_nritems(&leaf->header);
1782 data_end = leaf_data_end(root, leaf);
1784 if (btrfs_leaf_free_space(root, leaf) < data_size)
1786 slot = path->slots[0];
1787 old_data = btrfs_item_end(leaf->items + slot);
1790 BUG_ON(slot >= nritems);
1793 * item0..itemN ... dataN.offset..dataN.size .. data0.size
1795 /* first correct the data pointers */
1796 for (i = slot; i < nritems; i++) {
1797 u32 ioff = btrfs_item_offset(leaf->items + i);
1798 btrfs_set_item_offset(leaf->items + i,
1801 /* shift the data */
1802 btrfs_memmove(root, leaf, btrfs_leaf_data(leaf) +
1803 data_end - data_size, btrfs_leaf_data(leaf) +
1804 data_end, old_data - data_end);
1805 data_end = old_data;
1806 old_size = btrfs_item_size(leaf->items + slot);
1807 btrfs_set_item_size(leaf->items + slot, old_size + data_size);
1808 btrfs_mark_buffer_dirty(leaf_buf);
1811 if (btrfs_leaf_free_space(root, leaf) < 0)
1813 check_leaf(root, path, 0);
1818 * Given a key and some data, insert an item into the tree.
1819 * This does all the path init required, making room in the tree if needed.
1821 int btrfs_insert_empty_item(struct btrfs_trans_handle *trans, struct btrfs_root
1822 *root, struct btrfs_path *path, struct btrfs_key
1823 *cpu_key, u32 data_size)
1828 struct btrfs_leaf *leaf;
1829 struct buffer_head *leaf_buf;
1831 unsigned int data_end;
1832 struct btrfs_disk_key disk_key;
1834 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
1836 /* create a root if there isn't one */
1839 ret = btrfs_search_slot(trans, root, cpu_key, path, data_size, 1);
1846 slot_orig = path->slots[0];
1847 leaf_buf = path->nodes[0];
1848 leaf = btrfs_buffer_leaf(leaf_buf);
1850 nritems = btrfs_header_nritems(&leaf->header);
1851 data_end = leaf_data_end(root, leaf);
1853 if (btrfs_leaf_free_space(root, leaf) <
1854 sizeof(struct btrfs_item) + data_size) {
1857 slot = path->slots[0];
1859 if (slot != nritems) {
1861 unsigned int old_data = btrfs_item_end(leaf->items + slot);
1864 * item0..itemN ... dataN.offset..dataN.size .. data0.size
1866 /* first correct the data pointers */
1867 for (i = slot; i < nritems; i++) {
1868 u32 ioff = btrfs_item_offset(leaf->items + i);
1869 btrfs_set_item_offset(leaf->items + i,
1873 /* shift the items */
1874 btrfs_memmove(root, leaf, leaf->items + slot + 1,
1876 (nritems - slot) * sizeof(struct btrfs_item));
1878 /* shift the data */
1879 btrfs_memmove(root, leaf, btrfs_leaf_data(leaf) +
1880 data_end - data_size, btrfs_leaf_data(leaf) +
1881 data_end, old_data - data_end);
1882 data_end = old_data;
1884 /* setup the item for the new data */
1885 btrfs_memcpy(root, leaf, &leaf->items[slot].key, &disk_key,
1886 sizeof(struct btrfs_disk_key));
1887 btrfs_set_item_offset(leaf->items + slot, data_end - data_size);
1888 btrfs_set_item_size(leaf->items + slot, data_size);
1889 btrfs_set_header_nritems(&leaf->header, nritems + 1);
1890 btrfs_mark_buffer_dirty(leaf_buf);
1894 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
1896 if (btrfs_leaf_free_space(root, leaf) < 0)
1898 check_leaf(root, path, 0);
1904 * Given a key and some data, insert an item into the tree.
1905 * This does all the path init required, making room in the tree if needed.
1907 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
1908 *root, struct btrfs_key *cpu_key, void *data, u32
1912 struct btrfs_path *path;
1915 path = btrfs_alloc_path();
1917 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
1919 ptr = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
1920 path->slots[0], u8);
1921 btrfs_memcpy(root, path->nodes[0]->b_data,
1922 ptr, data, data_size);
1923 btrfs_mark_buffer_dirty(path->nodes[0]);
1925 btrfs_free_path(path);
1930 * delete the pointer from a given node.
1932 * If the delete empties a node, the node is removed from the tree,
1933 * continuing all the way the root if required. The root is converted into
1934 * a leaf if all the nodes are emptied.
1936 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1937 struct btrfs_path *path, int level, int slot)
1939 struct btrfs_node *node;
1940 struct buffer_head *parent = path->nodes[level];
1945 node = btrfs_buffer_node(parent);
1946 nritems = btrfs_header_nritems(&node->header);
1947 if (slot != nritems -1) {
1948 btrfs_memmove(root, node, node->ptrs + slot,
1949 node->ptrs + slot + 1,
1950 sizeof(struct btrfs_key_ptr) *
1951 (nritems - slot - 1));
1954 btrfs_set_header_nritems(&node->header, nritems);
1955 if (nritems == 0 && parent == root->node) {
1956 struct btrfs_header *header = btrfs_buffer_header(root->node);
1957 BUG_ON(btrfs_header_level(header) != 1);
1958 /* just turn the root into a leaf and break */
1959 btrfs_set_header_level(header, 0);
1960 } else if (slot == 0) {
1961 wret = fixup_low_keys(trans, root, path, &node->ptrs[0].key,
1966 btrfs_mark_buffer_dirty(parent);
1971 * delete the item at the leaf level in path. If that empties
1972 * the leaf, remove it from the tree
1974 int btrfs_del_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1975 struct btrfs_path *path)
1978 struct btrfs_leaf *leaf;
1979 struct buffer_head *leaf_buf;
1986 leaf_buf = path->nodes[0];
1987 leaf = btrfs_buffer_leaf(leaf_buf);
1988 slot = path->slots[0];
1989 doff = btrfs_item_offset(leaf->items + slot);
1990 dsize = btrfs_item_size(leaf->items + slot);
1991 nritems = btrfs_header_nritems(&leaf->header);
1993 if (slot != nritems - 1) {
1995 int data_end = leaf_data_end(root, leaf);
1996 btrfs_memmove(root, leaf, btrfs_leaf_data(leaf) +
1998 btrfs_leaf_data(leaf) + data_end,
2000 for (i = slot + 1; i < nritems; i++) {
2001 u32 ioff = btrfs_item_offset(leaf->items + i);
2002 btrfs_set_item_offset(leaf->items + i, ioff + dsize);
2004 btrfs_memmove(root, leaf, leaf->items + slot,
2005 leaf->items + slot + 1,
2006 sizeof(struct btrfs_item) *
2007 (nritems - slot - 1));
2009 btrfs_set_header_nritems(&leaf->header, nritems - 1);
2011 /* delete the leaf if we've emptied it */
2013 if (leaf_buf == root->node) {
2014 btrfs_set_header_level(&leaf->header, 0);
2016 clean_tree_block(trans, root, leaf_buf);
2017 wait_on_buffer(leaf_buf);
2018 wret = del_ptr(trans, root, path, 1, path->slots[1]);
2021 wret = btrfs_free_extent(trans, root,
2022 bh_blocknr(leaf_buf), 1, 1);
2027 int used = leaf_space_used(leaf, 0, nritems);
2029 wret = fixup_low_keys(trans, root, path,
2030 &leaf->items[0].key, 1);
2035 /* delete the leaf if it is mostly empty */
2036 if (used < BTRFS_LEAF_DATA_SIZE(root) / 3) {
2037 /* push_leaf_left fixes the path.
2038 * make sure the path still points to our leaf
2039 * for possible call to del_ptr below
2041 slot = path->slots[1];
2043 wret = push_leaf_left(trans, root, path, 1);
2044 if (wret < 0 && wret != -ENOSPC)
2046 if (path->nodes[0] == leaf_buf &&
2047 btrfs_header_nritems(&leaf->header)) {
2048 wret = push_leaf_right(trans, root, path, 1);
2049 if (wret < 0 && wret != -ENOSPC)
2052 if (btrfs_header_nritems(&leaf->header) == 0) {
2053 u64 blocknr = bh_blocknr(leaf_buf);
2054 clean_tree_block(trans, root, leaf_buf);
2055 wait_on_buffer(leaf_buf);
2056 wret = del_ptr(trans, root, path, 1, slot);
2059 btrfs_block_release(root, leaf_buf);
2060 wret = btrfs_free_extent(trans, root, blocknr,
2065 btrfs_mark_buffer_dirty(leaf_buf);
2066 btrfs_block_release(root, leaf_buf);
2069 btrfs_mark_buffer_dirty(leaf_buf);
2076 * walk up the tree as far as required to find the next leaf.
2077 * returns 0 if it found something or 1 if there are no greater leaves.
2078 * returns < 0 on io errors.
2080 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
2085 struct buffer_head *c;
2086 struct btrfs_node *c_node;
2087 struct buffer_head *next = NULL;
2089 while(level < BTRFS_MAX_LEVEL) {
2090 if (!path->nodes[level])
2092 slot = path->slots[level] + 1;
2093 c = path->nodes[level];
2094 c_node = btrfs_buffer_node(c);
2095 if (slot >= btrfs_header_nritems(&c_node->header)) {
2099 blocknr = btrfs_node_blockptr(c_node, slot);
2101 btrfs_block_release(root, next);
2103 reada_for_search(root, path, level, slot);
2104 next = read_tree_block(root, blocknr);
2107 path->slots[level] = slot;
2110 c = path->nodes[level];
2111 btrfs_block_release(root, c);
2112 path->nodes[level] = next;
2113 path->slots[level] = 0;
2117 reada_for_search(root, path, level, slot);
2118 next = read_tree_block(root,
2119 btrfs_node_blockptr(btrfs_buffer_node(next), 0));