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.
19 #include <linux/sched.h>
22 #include "transaction.h"
23 #include "print-tree.h"
25 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
26 *root, struct btrfs_path *path, int level);
27 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
28 *root, struct btrfs_key *ins_key,
29 struct btrfs_path *path, int data_size, int extend);
30 static int push_node_left(struct btrfs_trans_handle *trans,
31 struct btrfs_root *root, struct extent_buffer *dst,
32 struct extent_buffer *src);
33 static int balance_node_right(struct btrfs_trans_handle *trans,
34 struct btrfs_root *root,
35 struct extent_buffer *dst_buf,
36 struct extent_buffer *src_buf);
37 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
38 struct btrfs_path *path, int level, int slot);
40 inline void btrfs_init_path(struct btrfs_path *p)
42 memset(p, 0, sizeof(*p));
45 struct btrfs_path *btrfs_alloc_path(void)
47 struct btrfs_path *path;
48 path = kmem_cache_alloc(btrfs_path_cachep, GFP_NOFS);
50 btrfs_init_path(path);
56 void btrfs_free_path(struct btrfs_path *p)
58 btrfs_release_path(NULL, p);
59 kmem_cache_free(btrfs_path_cachep, p);
62 void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
65 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
68 free_extent_buffer(p->nodes[i]);
70 memset(p, 0, sizeof(*p));
73 static int __btrfs_cow_block(struct btrfs_trans_handle *trans,
74 struct btrfs_root *root,
75 struct extent_buffer *buf,
76 struct extent_buffer *parent, int parent_slot,
77 struct extent_buffer **cow_ret,
78 u64 search_start, u64 empty_size)
81 struct extent_buffer *cow;
84 int different_trans = 0;
86 struct btrfs_key first_key;
89 root_gen = trans->transid;
94 WARN_ON(root->ref_cows && trans->transid !=
95 root->fs_info->running_transaction->transid);
96 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
98 level = btrfs_header_level(buf);
99 nritems = btrfs_header_nritems(buf);
102 btrfs_item_key_to_cpu(buf, &first_key, 0);
104 btrfs_node_key_to_cpu(buf, &first_key, 0);
106 first_key.objectid = 0;
108 cow = __btrfs_alloc_free_block(trans, root, buf->len,
109 root->root_key.objectid,
110 root_gen, first_key.objectid, level,
111 search_start, empty_size);
115 copy_extent_buffer(cow, buf, 0, 0, cow->len);
116 btrfs_set_header_bytenr(cow, cow->start);
117 btrfs_set_header_generation(cow, trans->transid);
118 btrfs_set_header_owner(cow, root->root_key.objectid);
120 WARN_ON(btrfs_header_generation(buf) > trans->transid);
121 if (btrfs_header_generation(buf) != trans->transid) {
123 ret = btrfs_inc_ref(trans, root, buf);
127 clean_tree_block(trans, root, buf);
130 if (buf == root->node) {
131 root_gen = btrfs_header_generation(buf);
133 extent_buffer_get(cow);
134 if (buf != root->commit_root) {
135 btrfs_free_extent(trans, root, buf->start,
136 buf->len, root->root_key.objectid,
139 free_extent_buffer(buf);
141 root_gen = btrfs_header_generation(parent);
142 btrfs_set_node_blockptr(parent, parent_slot,
144 WARN_ON(trans->transid == 0);
145 btrfs_set_node_ptr_generation(parent, parent_slot,
147 btrfs_mark_buffer_dirty(parent);
148 WARN_ON(btrfs_header_generation(parent) != trans->transid);
149 btrfs_free_extent(trans, root, buf->start, buf->len,
150 btrfs_header_owner(parent), root_gen,
153 free_extent_buffer(buf);
154 btrfs_mark_buffer_dirty(cow);
159 int btrfs_cow_block(struct btrfs_trans_handle *trans,
160 struct btrfs_root *root, struct extent_buffer *buf,
161 struct extent_buffer *parent, int parent_slot,
162 struct extent_buffer **cow_ret)
166 if (trans->transaction != root->fs_info->running_transaction) {
167 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
168 root->fs_info->running_transaction->transid);
171 if (trans->transid != root->fs_info->generation) {
172 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
173 root->fs_info->generation);
176 if (btrfs_header_generation(buf) == trans->transid) {
181 search_start = buf->start & ~((u64)BTRFS_BLOCK_GROUP_SIZE - 1);
182 ret = __btrfs_cow_block(trans, root, buf, parent,
183 parent_slot, cow_ret, search_start, 0);
187 static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
189 if (blocknr < other && other - (blocknr + blocksize) < 32768)
191 if (blocknr > other && blocknr - (other + blocksize) < 32768)
197 * compare two keys in a memcmp fashion
199 static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
203 btrfs_disk_key_to_cpu(&k1, disk);
205 if (k1.objectid > k2->objectid)
207 if (k1.objectid < k2->objectid)
209 if (k1.type > k2->type)
211 if (k1.type < k2->type)
213 if (k1.offset > k2->offset)
215 if (k1.offset < k2->offset)
221 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
222 struct btrfs_root *root, struct extent_buffer *parent,
223 int start_slot, int cache_only, u64 *last_ret,
224 struct btrfs_key *progress)
226 struct extent_buffer *cur;
227 struct extent_buffer *tmp;
229 u64 search_start = *last_ret;
239 int progress_passed = 0;
240 struct btrfs_disk_key disk_key;
242 parent_level = btrfs_header_level(parent);
243 if (cache_only && parent_level != 1)
246 if (trans->transaction != root->fs_info->running_transaction) {
247 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
248 root->fs_info->running_transaction->transid);
251 if (trans->transid != root->fs_info->generation) {
252 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
253 root->fs_info->generation);
257 parent_nritems = btrfs_header_nritems(parent);
258 blocksize = btrfs_level_size(root, parent_level - 1);
259 end_slot = parent_nritems;
261 if (parent_nritems == 1)
264 for (i = start_slot; i < end_slot; i++) {
267 if (!parent->map_token) {
268 map_extent_buffer(parent,
269 btrfs_node_key_ptr_offset(i),
270 sizeof(struct btrfs_key_ptr),
271 &parent->map_token, &parent->kaddr,
272 &parent->map_start, &parent->map_len,
275 btrfs_node_key(parent, &disk_key, i);
276 if (!progress_passed && comp_keys(&disk_key, progress) < 0)
280 blocknr = btrfs_node_blockptr(parent, i);
282 last_block = blocknr;
285 other = btrfs_node_blockptr(parent, i - 1);
286 close = close_blocks(blocknr, other, blocksize);
288 if (close && i < end_slot - 2) {
289 other = btrfs_node_blockptr(parent, i + 1);
290 close = close_blocks(blocknr, other, blocksize);
293 last_block = blocknr;
296 if (parent->map_token) {
297 unmap_extent_buffer(parent, parent->map_token,
299 parent->map_token = NULL;
302 cur = btrfs_find_tree_block(root, blocknr, blocksize);
304 uptodate = btrfs_buffer_uptodate(cur);
307 if (!cur || !uptodate) {
309 free_extent_buffer(cur);
313 cur = read_tree_block(root, blocknr,
315 } else if (!uptodate) {
316 btrfs_read_buffer(cur);
319 if (search_start == 0)
320 search_start = last_block;
322 err = __btrfs_cow_block(trans, root, cur, parent, i,
325 (end_slot - i) * blocksize));
327 free_extent_buffer(cur);
330 search_start = tmp->start;
331 last_block = tmp->start;
332 *last_ret = search_start;
333 if (parent_level == 1)
334 btrfs_clear_buffer_defrag(tmp);
335 free_extent_buffer(tmp);
337 if (parent->map_token) {
338 unmap_extent_buffer(parent, parent->map_token,
340 parent->map_token = NULL;
346 * The leaf data grows from end-to-front in the node.
347 * this returns the address of the start of the last item,
348 * which is the stop of the leaf data stack
350 static inline unsigned int leaf_data_end(struct btrfs_root *root,
351 struct extent_buffer *leaf)
353 u32 nr = btrfs_header_nritems(leaf);
355 return BTRFS_LEAF_DATA_SIZE(root);
356 return btrfs_item_offset_nr(leaf, nr - 1);
359 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
362 struct extent_buffer *parent = NULL;
363 struct extent_buffer *node = path->nodes[level];
364 struct btrfs_disk_key parent_key;
365 struct btrfs_disk_key node_key;
368 struct btrfs_key cpukey;
369 u32 nritems = btrfs_header_nritems(node);
371 if (path->nodes[level + 1])
372 parent = path->nodes[level + 1];
374 slot = path->slots[level];
375 BUG_ON(nritems == 0);
377 parent_slot = path->slots[level + 1];
378 btrfs_node_key(parent, &parent_key, parent_slot);
379 btrfs_node_key(node, &node_key, 0);
380 BUG_ON(memcmp(&parent_key, &node_key,
381 sizeof(struct btrfs_disk_key)));
382 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
383 btrfs_header_bytenr(node));
385 BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
387 btrfs_node_key_to_cpu(node, &cpukey, slot - 1);
388 btrfs_node_key(node, &node_key, slot);
389 BUG_ON(comp_keys(&node_key, &cpukey) <= 0);
391 if (slot < nritems - 1) {
392 btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
393 btrfs_node_key(node, &node_key, slot);
394 BUG_ON(comp_keys(&node_key, &cpukey) >= 0);
399 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
402 struct extent_buffer *leaf = path->nodes[level];
403 struct extent_buffer *parent = NULL;
405 struct btrfs_key cpukey;
406 struct btrfs_disk_key parent_key;
407 struct btrfs_disk_key leaf_key;
408 int slot = path->slots[0];
410 u32 nritems = btrfs_header_nritems(leaf);
412 if (path->nodes[level + 1])
413 parent = path->nodes[level + 1];
419 parent_slot = path->slots[level + 1];
420 btrfs_node_key(parent, &parent_key, parent_slot);
421 btrfs_item_key(leaf, &leaf_key, 0);
423 BUG_ON(memcmp(&parent_key, &leaf_key,
424 sizeof(struct btrfs_disk_key)));
425 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
426 btrfs_header_bytenr(leaf));
429 for (i = 0; nritems > 1 && i < nritems - 2; i++) {
430 btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
431 btrfs_item_key(leaf, &leaf_key, i);
432 if (comp_keys(&leaf_key, &cpukey) >= 0) {
433 btrfs_print_leaf(root, leaf);
434 printk("slot %d offset bad key\n", i);
437 if (btrfs_item_offset_nr(leaf, i) !=
438 btrfs_item_end_nr(leaf, i + 1)) {
439 btrfs_print_leaf(root, leaf);
440 printk("slot %d offset bad\n", i);
444 if (btrfs_item_offset_nr(leaf, i) +
445 btrfs_item_size_nr(leaf, i) !=
446 BTRFS_LEAF_DATA_SIZE(root)) {
447 btrfs_print_leaf(root, leaf);
448 printk("slot %d first offset bad\n", i);
454 if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
455 btrfs_print_leaf(root, leaf);
456 printk("slot %d bad size \n", nritems - 1);
461 if (slot != 0 && slot < nritems - 1) {
462 btrfs_item_key(leaf, &leaf_key, slot);
463 btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
464 if (comp_keys(&leaf_key, &cpukey) <= 0) {
465 btrfs_print_leaf(root, leaf);
466 printk("slot %d offset bad key\n", slot);
469 if (btrfs_item_offset_nr(leaf, slot - 1) !=
470 btrfs_item_end_nr(leaf, slot)) {
471 btrfs_print_leaf(root, leaf);
472 printk("slot %d offset bad\n", slot);
476 if (slot < nritems - 1) {
477 btrfs_item_key(leaf, &leaf_key, slot);
478 btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
479 BUG_ON(comp_keys(&leaf_key, &cpukey) >= 0);
480 if (btrfs_item_offset_nr(leaf, slot) !=
481 btrfs_item_end_nr(leaf, slot + 1)) {
482 btrfs_print_leaf(root, leaf);
483 printk("slot %d offset bad\n", slot);
487 BUG_ON(btrfs_item_offset_nr(leaf, 0) +
488 btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
492 static int check_block(struct btrfs_root *root, struct btrfs_path *path,
497 struct extent_buffer *buf = path->nodes[level];
499 if (memcmp_extent_buffer(buf, root->fs_info->fsid,
500 (unsigned long)btrfs_header_fsid(buf),
502 printk("warning bad block %Lu\n", buf->start);
507 return check_leaf(root, path, level);
508 return check_node(root, path, level);
512 * search for key in the extent_buffer. The items start at offset p,
513 * and they are item_size apart. There are 'max' items in p.
515 * the slot in the array is returned via slot, and it points to
516 * the place where you would insert key if it is not found in
519 * slot may point to max if the key is bigger than all of the keys
521 static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
522 int item_size, struct btrfs_key *key,
529 struct btrfs_disk_key *tmp = NULL;
530 struct btrfs_disk_key unaligned;
531 unsigned long offset;
532 char *map_token = NULL;
534 unsigned long map_start = 0;
535 unsigned long map_len = 0;
539 mid = (low + high) / 2;
540 offset = p + mid * item_size;
542 if (!map_token || offset < map_start ||
543 (offset + sizeof(struct btrfs_disk_key)) >
544 map_start + map_len) {
546 unmap_extent_buffer(eb, map_token, KM_USER0);
549 err = map_extent_buffer(eb, offset,
550 sizeof(struct btrfs_disk_key),
552 &map_start, &map_len, KM_USER0);
555 tmp = (struct btrfs_disk_key *)(kaddr + offset -
558 read_extent_buffer(eb, &unaligned,
559 offset, sizeof(unaligned));
564 tmp = (struct btrfs_disk_key *)(kaddr + offset -
567 ret = comp_keys(tmp, key);
576 unmap_extent_buffer(eb, map_token, KM_USER0);
582 unmap_extent_buffer(eb, map_token, KM_USER0);
587 * simple bin_search frontend that does the right thing for
590 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
591 int level, int *slot)
594 return generic_bin_search(eb,
595 offsetof(struct btrfs_leaf, items),
596 sizeof(struct btrfs_item),
597 key, btrfs_header_nritems(eb),
600 return generic_bin_search(eb,
601 offsetof(struct btrfs_node, ptrs),
602 sizeof(struct btrfs_key_ptr),
603 key, btrfs_header_nritems(eb),
609 static struct extent_buffer *read_node_slot(struct btrfs_root *root,
610 struct extent_buffer *parent, int slot)
614 if (slot >= btrfs_header_nritems(parent))
616 return read_tree_block(root, btrfs_node_blockptr(parent, slot),
617 btrfs_level_size(root, btrfs_header_level(parent) - 1));
620 static int balance_level(struct btrfs_trans_handle *trans, struct btrfs_root
621 *root, struct btrfs_path *path, int level)
623 struct extent_buffer *right = NULL;
624 struct extent_buffer *mid;
625 struct extent_buffer *left = NULL;
626 struct extent_buffer *parent = NULL;
630 int orig_slot = path->slots[level];
631 int err_on_enospc = 0;
637 mid = path->nodes[level];
638 WARN_ON(btrfs_header_generation(mid) != trans->transid);
640 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
642 if (level < BTRFS_MAX_LEVEL - 1)
643 parent = path->nodes[level + 1];
644 pslot = path->slots[level + 1];
647 * deal with the case where there is only one pointer in the root
648 * by promoting the node below to a root
651 struct extent_buffer *child;
653 if (btrfs_header_nritems(mid) != 1)
656 /* promote the child to a root */
657 child = read_node_slot(root, mid, 0);
660 path->nodes[level] = NULL;
661 clean_tree_block(trans, root, mid);
662 wait_on_tree_block_writeback(root, mid);
663 /* once for the path */
664 free_extent_buffer(mid);
665 ret = btrfs_free_extent(trans, root, mid->start, mid->len,
666 root->root_key.objectid,
667 btrfs_header_generation(mid), 0, 0, 1);
668 /* once for the root ptr */
669 free_extent_buffer(mid);
672 if (btrfs_header_nritems(mid) >
673 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
676 if (btrfs_header_nritems(mid) < 2)
679 left = read_node_slot(root, parent, pslot - 1);
681 wret = btrfs_cow_block(trans, root, left,
682 parent, pslot - 1, &left);
688 right = read_node_slot(root, parent, pslot + 1);
690 wret = btrfs_cow_block(trans, root, right,
691 parent, pslot + 1, &right);
698 /* first, try to make some room in the middle buffer */
700 orig_slot += btrfs_header_nritems(left);
701 wret = push_node_left(trans, root, left, mid);
704 if (btrfs_header_nritems(mid) < 2)
709 * then try to empty the right most buffer into the middle
712 wret = push_node_left(trans, root, mid, right);
713 if (wret < 0 && wret != -ENOSPC)
715 if (btrfs_header_nritems(right) == 0) {
716 u64 bytenr = right->start;
717 u64 generation = btrfs_header_generation(parent);
718 u32 blocksize = right->len;
720 clean_tree_block(trans, root, right);
721 wait_on_tree_block_writeback(root, right);
722 free_extent_buffer(right);
724 wret = del_ptr(trans, root, path, level + 1, pslot +
728 wret = btrfs_free_extent(trans, root, bytenr,
730 btrfs_header_owner(parent),
731 generation, 0, 0, 1);
735 struct btrfs_disk_key right_key;
736 btrfs_node_key(right, &right_key, 0);
737 btrfs_set_node_key(parent, &right_key, pslot + 1);
738 btrfs_mark_buffer_dirty(parent);
741 if (btrfs_header_nritems(mid) == 1) {
743 * we're not allowed to leave a node with one item in the
744 * tree during a delete. A deletion from lower in the tree
745 * could try to delete the only pointer in this node.
746 * So, pull some keys from the left.
747 * There has to be a left pointer at this point because
748 * otherwise we would have pulled some pointers from the
752 wret = balance_node_right(trans, root, mid, left);
759 if (btrfs_header_nritems(mid) == 0) {
760 /* we've managed to empty the middle node, drop it */
761 u64 root_gen = btrfs_header_generation(parent);
762 u64 bytenr = mid->start;
763 u32 blocksize = mid->len;
764 clean_tree_block(trans, root, mid);
765 wait_on_tree_block_writeback(root, mid);
766 free_extent_buffer(mid);
768 wret = del_ptr(trans, root, path, level + 1, pslot);
771 wret = btrfs_free_extent(trans, root, bytenr, blocksize,
772 btrfs_header_owner(parent),
777 /* update the parent key to reflect our changes */
778 struct btrfs_disk_key mid_key;
779 btrfs_node_key(mid, &mid_key, 0);
780 btrfs_set_node_key(parent, &mid_key, pslot);
781 btrfs_mark_buffer_dirty(parent);
784 /* update the path */
786 if (btrfs_header_nritems(left) > orig_slot) {
787 extent_buffer_get(left);
788 path->nodes[level] = left;
789 path->slots[level + 1] -= 1;
790 path->slots[level] = orig_slot;
792 free_extent_buffer(mid);
794 orig_slot -= btrfs_header_nritems(left);
795 path->slots[level] = orig_slot;
798 /* double check we haven't messed things up */
799 check_block(root, path, level);
801 btrfs_node_blockptr(path->nodes[level], path->slots[level]))
805 free_extent_buffer(right);
807 free_extent_buffer(left);
811 /* returns zero if the push worked, non-zero otherwise */
812 static int push_nodes_for_insert(struct btrfs_trans_handle *trans,
813 struct btrfs_root *root,
814 struct btrfs_path *path, int level)
816 struct extent_buffer *right = NULL;
817 struct extent_buffer *mid;
818 struct extent_buffer *left = NULL;
819 struct extent_buffer *parent = NULL;
823 int orig_slot = path->slots[level];
829 mid = path->nodes[level];
830 WARN_ON(btrfs_header_generation(mid) != trans->transid);
831 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
833 if (level < BTRFS_MAX_LEVEL - 1)
834 parent = path->nodes[level + 1];
835 pslot = path->slots[level + 1];
840 left = read_node_slot(root, parent, pslot - 1);
842 /* first, try to make some room in the middle buffer */
845 left_nr = btrfs_header_nritems(left);
846 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
849 ret = btrfs_cow_block(trans, root, left, parent,
854 wret = push_node_left(trans, root,
861 struct btrfs_disk_key disk_key;
862 orig_slot += left_nr;
863 btrfs_node_key(mid, &disk_key, 0);
864 btrfs_set_node_key(parent, &disk_key, pslot);
865 btrfs_mark_buffer_dirty(parent);
866 if (btrfs_header_nritems(left) > orig_slot) {
867 path->nodes[level] = left;
868 path->slots[level + 1] -= 1;
869 path->slots[level] = orig_slot;
870 free_extent_buffer(mid);
873 btrfs_header_nritems(left);
874 path->slots[level] = orig_slot;
875 free_extent_buffer(left);
879 free_extent_buffer(left);
881 right= read_node_slot(root, parent, pslot + 1);
884 * then try to empty the right most buffer into the middle
888 right_nr = btrfs_header_nritems(right);
889 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
892 ret = btrfs_cow_block(trans, root, right,
898 wret = balance_node_right(trans, root,
905 struct btrfs_disk_key disk_key;
907 btrfs_node_key(right, &disk_key, 0);
908 btrfs_set_node_key(parent, &disk_key, pslot + 1);
909 btrfs_mark_buffer_dirty(parent);
911 if (btrfs_header_nritems(mid) <= orig_slot) {
912 path->nodes[level] = right;
913 path->slots[level + 1] += 1;
914 path->slots[level] = orig_slot -
915 btrfs_header_nritems(mid);
916 free_extent_buffer(mid);
918 free_extent_buffer(right);
922 free_extent_buffer(right);
928 * readahead one full node of leaves
930 static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
933 struct extent_buffer *node;
939 int direction = path->reada;
940 struct extent_buffer *eb;
948 if (!path->nodes[level])
951 node = path->nodes[level];
952 search = btrfs_node_blockptr(node, slot);
953 blocksize = btrfs_level_size(root, level - 1);
954 eb = btrfs_find_tree_block(root, search, blocksize);
956 free_extent_buffer(eb);
960 highest_read = search;
961 lowest_read = search;
963 nritems = btrfs_header_nritems(node);
970 } else if (direction > 0) {
975 search = btrfs_node_blockptr(node, nr);
976 if ((search >= lowest_read && search <= highest_read) ||
977 (search < lowest_read && lowest_read - search <= 32768) ||
978 (search > highest_read && search - highest_read <= 32768)) {
979 readahead_tree_block(root, search, blocksize);
983 if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
985 if(nread > (1024 * 1024) || nscan > 128)
988 if (search < lowest_read)
989 lowest_read = search;
990 if (search > highest_read)
991 highest_read = search;
995 * look for key in the tree. path is filled in with nodes along the way
996 * if key is found, we return zero and you can find the item in the leaf
997 * level of the path (level 0)
999 * If the key isn't found, the path points to the slot where it should
1000 * be inserted, and 1 is returned. If there are other errors during the
1001 * search a negative error number is returned.
1003 * if ins_len > 0, nodes and leaves will be split as we walk down the
1004 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
1007 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
1008 *root, struct btrfs_key *key, struct btrfs_path *p, int
1011 struct extent_buffer *b;
1017 int should_reada = p->reada;
1018 u8 lowest_level = 0;
1020 lowest_level = p->lowest_level;
1021 WARN_ON(lowest_level && ins_len);
1022 WARN_ON(p->nodes[0] != NULL);
1023 WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
1026 extent_buffer_get(b);
1028 level = btrfs_header_level(b);
1031 wret = btrfs_cow_block(trans, root, b,
1032 p->nodes[level + 1],
1033 p->slots[level + 1],
1036 free_extent_buffer(b);
1040 BUG_ON(!cow && ins_len);
1041 if (level != btrfs_header_level(b))
1043 level = btrfs_header_level(b);
1044 p->nodes[level] = b;
1045 ret = check_block(root, p, level);
1048 ret = bin_search(b, key, level, &slot);
1050 if (ret && slot > 0)
1052 p->slots[level] = slot;
1053 if (ins_len > 0 && btrfs_header_nritems(b) >=
1054 BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1055 int sret = split_node(trans, root, p, level);
1059 b = p->nodes[level];
1060 slot = p->slots[level];
1061 } else if (ins_len < 0) {
1062 int sret = balance_level(trans, root, p,
1066 b = p->nodes[level];
1068 btrfs_release_path(NULL, p);
1071 slot = p->slots[level];
1072 BUG_ON(btrfs_header_nritems(b) == 1);
1074 /* this is only true while dropping a snapshot */
1075 if (level == lowest_level)
1077 bytenr = btrfs_node_blockptr(b, slot);
1078 ptr_gen = btrfs_node_ptr_generation(b, slot);
1080 reada_for_search(root, p, level, slot);
1081 b = read_tree_block(root, bytenr,
1082 btrfs_level_size(root, level - 1));
1083 if (ptr_gen != btrfs_header_generation(b)) {
1084 printk("block %llu bad gen wanted %llu "
1086 (unsigned long long)b->start,
1087 (unsigned long long)ptr_gen,
1088 (unsigned long long)btrfs_header_generation(b));
1091 p->slots[level] = slot;
1092 if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
1093 sizeof(struct btrfs_item) + ins_len) {
1094 int sret = split_leaf(trans, root, key,
1095 p, ins_len, ret == 0);
1107 * adjust the pointers going up the tree, starting at level
1108 * making sure the right key of each node is points to 'key'.
1109 * This is used after shifting pointers to the left, so it stops
1110 * fixing up pointers when a given leaf/node is not in slot 0 of the
1113 * If this fails to write a tree block, it returns -1, but continues
1114 * fixing up the blocks in ram so the tree is consistent.
1116 static int fixup_low_keys(struct btrfs_trans_handle *trans,
1117 struct btrfs_root *root, struct btrfs_path *path,
1118 struct btrfs_disk_key *key, int level)
1122 struct extent_buffer *t;
1124 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1125 int tslot = path->slots[i];
1126 if (!path->nodes[i])
1129 btrfs_set_node_key(t, key, tslot);
1130 btrfs_mark_buffer_dirty(path->nodes[i]);
1138 * try to push data from one node into the next node left in the
1141 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1142 * error, and > 0 if there was no room in the left hand block.
1144 static int push_node_left(struct btrfs_trans_handle *trans, struct btrfs_root
1145 *root, struct extent_buffer *dst,
1146 struct extent_buffer *src)
1153 src_nritems = btrfs_header_nritems(src);
1154 dst_nritems = btrfs_header_nritems(dst);
1155 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1156 WARN_ON(btrfs_header_generation(src) != trans->transid);
1157 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1159 if (push_items <= 0) {
1163 if (src_nritems < push_items)
1164 push_items = src_nritems;
1166 copy_extent_buffer(dst, src,
1167 btrfs_node_key_ptr_offset(dst_nritems),
1168 btrfs_node_key_ptr_offset(0),
1169 push_items * sizeof(struct btrfs_key_ptr));
1171 if (push_items < src_nritems) {
1172 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1173 btrfs_node_key_ptr_offset(push_items),
1174 (src_nritems - push_items) *
1175 sizeof(struct btrfs_key_ptr));
1177 btrfs_set_header_nritems(src, src_nritems - push_items);
1178 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1179 btrfs_mark_buffer_dirty(src);
1180 btrfs_mark_buffer_dirty(dst);
1185 * try to push data from one node into the next node right in the
1188 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1189 * error, and > 0 if there was no room in the right hand block.
1191 * this will only push up to 1/2 the contents of the left node over
1193 static int balance_node_right(struct btrfs_trans_handle *trans,
1194 struct btrfs_root *root,
1195 struct extent_buffer *dst,
1196 struct extent_buffer *src)
1204 WARN_ON(btrfs_header_generation(src) != trans->transid);
1205 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1207 src_nritems = btrfs_header_nritems(src);
1208 dst_nritems = btrfs_header_nritems(dst);
1209 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1210 if (push_items <= 0)
1213 max_push = src_nritems / 2 + 1;
1214 /* don't try to empty the node */
1215 if (max_push >= src_nritems)
1218 if (max_push < push_items)
1219 push_items = max_push;
1221 memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1222 btrfs_node_key_ptr_offset(0),
1224 sizeof(struct btrfs_key_ptr));
1226 copy_extent_buffer(dst, src,
1227 btrfs_node_key_ptr_offset(0),
1228 btrfs_node_key_ptr_offset(src_nritems - push_items),
1229 push_items * sizeof(struct btrfs_key_ptr));
1231 btrfs_set_header_nritems(src, src_nritems - push_items);
1232 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1234 btrfs_mark_buffer_dirty(src);
1235 btrfs_mark_buffer_dirty(dst);
1240 * helper function to insert a new root level in the tree.
1241 * A new node is allocated, and a single item is inserted to
1242 * point to the existing root
1244 * returns zero on success or < 0 on failure.
1246 static int insert_new_root(struct btrfs_trans_handle *trans,
1247 struct btrfs_root *root,
1248 struct btrfs_path *path, int level)
1252 struct extent_buffer *lower;
1253 struct extent_buffer *c;
1254 struct btrfs_disk_key lower_key;
1256 BUG_ON(path->nodes[level]);
1257 BUG_ON(path->nodes[level-1] != root->node);
1260 root_gen = trans->transid;
1264 lower = path->nodes[level-1];
1266 btrfs_item_key(lower, &lower_key, 0);
1268 btrfs_node_key(lower, &lower_key, 0);
1270 c = __btrfs_alloc_free_block(trans, root, root->nodesize,
1271 root->root_key.objectid,
1272 root_gen, lower_key.objectid, level,
1273 root->node->start, 0);
1276 memset_extent_buffer(c, 0, 0, root->nodesize);
1277 btrfs_set_header_nritems(c, 1);
1278 btrfs_set_header_level(c, level);
1279 btrfs_set_header_bytenr(c, c->start);
1280 btrfs_set_header_generation(c, trans->transid);
1281 btrfs_set_header_owner(c, root->root_key.objectid);
1283 write_extent_buffer(c, root->fs_info->fsid,
1284 (unsigned long)btrfs_header_fsid(c),
1286 btrfs_set_node_key(c, &lower_key, 0);
1287 btrfs_set_node_blockptr(c, 0, lower->start);
1288 lower_gen = btrfs_header_generation(lower);
1289 WARN_ON(lower_gen == 0);
1291 btrfs_set_node_ptr_generation(c, 0, lower_gen);
1293 btrfs_mark_buffer_dirty(c);
1295 /* the super has an extra ref to root->node */
1296 free_extent_buffer(root->node);
1298 extent_buffer_get(c);
1299 path->nodes[level] = c;
1300 path->slots[level] = 0;
1302 if (root->ref_cows && lower_gen != trans->transid) {
1303 struct btrfs_path *back_path = btrfs_alloc_path();
1305 ret = btrfs_insert_extent_backref(trans,
1306 root->fs_info->extent_root,
1308 root->root_key.objectid,
1309 trans->transid, 0, 0);
1311 btrfs_free_path(back_path);
1317 * worker function to insert a single pointer in a node.
1318 * the node should have enough room for the pointer already
1320 * slot and level indicate where you want the key to go, and
1321 * blocknr is the block the key points to.
1323 * returns zero on success and < 0 on any error
1325 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1326 *root, struct btrfs_path *path, struct btrfs_disk_key
1327 *key, u64 bytenr, int slot, int level)
1329 struct extent_buffer *lower;
1332 BUG_ON(!path->nodes[level]);
1333 lower = path->nodes[level];
1334 nritems = btrfs_header_nritems(lower);
1337 if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1339 if (slot != nritems) {
1340 memmove_extent_buffer(lower,
1341 btrfs_node_key_ptr_offset(slot + 1),
1342 btrfs_node_key_ptr_offset(slot),
1343 (nritems - slot) * sizeof(struct btrfs_key_ptr));
1345 btrfs_set_node_key(lower, key, slot);
1346 btrfs_set_node_blockptr(lower, slot, bytenr);
1347 WARN_ON(trans->transid == 0);
1348 btrfs_set_node_ptr_generation(lower, slot, trans->transid);
1349 btrfs_set_header_nritems(lower, nritems + 1);
1350 btrfs_mark_buffer_dirty(lower);
1355 * split the node at the specified level in path in two.
1356 * The path is corrected to point to the appropriate node after the split
1358 * Before splitting this tries to make some room in the node by pushing
1359 * left and right, if either one works, it returns right away.
1361 * returns 0 on success and < 0 on failure
1363 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1364 *root, struct btrfs_path *path, int level)
1367 struct extent_buffer *c;
1368 struct extent_buffer *split;
1369 struct btrfs_disk_key disk_key;
1375 c = path->nodes[level];
1376 WARN_ON(btrfs_header_generation(c) != trans->transid);
1377 if (c == root->node) {
1378 /* trying to split the root, lets make a new one */
1379 ret = insert_new_root(trans, root, path, level + 1);
1383 ret = push_nodes_for_insert(trans, root, path, level);
1384 c = path->nodes[level];
1385 if (!ret && btrfs_header_nritems(c) <
1386 BTRFS_NODEPTRS_PER_BLOCK(root) - 1)
1392 c_nritems = btrfs_header_nritems(c);
1394 root_gen = trans->transid;
1398 btrfs_node_key(c, &disk_key, 0);
1399 split = __btrfs_alloc_free_block(trans, root, root->nodesize,
1400 root->root_key.objectid,
1402 btrfs_disk_key_objectid(&disk_key),
1403 level, c->start, 0);
1405 return PTR_ERR(split);
1407 btrfs_set_header_flags(split, btrfs_header_flags(c));
1408 btrfs_set_header_level(split, btrfs_header_level(c));
1409 btrfs_set_header_bytenr(split, split->start);
1410 btrfs_set_header_generation(split, trans->transid);
1411 btrfs_set_header_owner(split, root->root_key.objectid);
1412 write_extent_buffer(split, root->fs_info->fsid,
1413 (unsigned long)btrfs_header_fsid(split),
1416 mid = (c_nritems + 1) / 2;
1418 copy_extent_buffer(split, c,
1419 btrfs_node_key_ptr_offset(0),
1420 btrfs_node_key_ptr_offset(mid),
1421 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1422 btrfs_set_header_nritems(split, c_nritems - mid);
1423 btrfs_set_header_nritems(c, mid);
1426 btrfs_mark_buffer_dirty(c);
1427 btrfs_mark_buffer_dirty(split);
1429 btrfs_node_key(split, &disk_key, 0);
1430 wret = insert_ptr(trans, root, path, &disk_key, split->start,
1431 path->slots[level + 1] + 1,
1436 if (path->slots[level] >= mid) {
1437 path->slots[level] -= mid;
1438 free_extent_buffer(c);
1439 path->nodes[level] = split;
1440 path->slots[level + 1] += 1;
1442 free_extent_buffer(split);
1448 * how many bytes are required to store the items in a leaf. start
1449 * and nr indicate which items in the leaf to check. This totals up the
1450 * space used both by the item structs and the item data
1452 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1455 int nritems = btrfs_header_nritems(l);
1456 int end = min(nritems, start + nr) - 1;
1460 data_len = btrfs_item_end_nr(l, start);
1461 data_len = data_len - btrfs_item_offset_nr(l, end);
1462 data_len += sizeof(struct btrfs_item) * nr;
1463 WARN_ON(data_len < 0);
1468 * The space between the end of the leaf items and
1469 * the start of the leaf data. IOW, how much room
1470 * the leaf has left for both items and data
1472 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
1474 int nritems = btrfs_header_nritems(leaf);
1476 ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
1478 printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
1479 ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
1480 leaf_space_used(leaf, 0, nritems), nritems);
1486 * push some data in the path leaf to the right, trying to free up at
1487 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1489 * returns 1 if the push failed because the other node didn't have enough
1490 * room, 0 if everything worked out and < 0 if there were major errors.
1492 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1493 *root, struct btrfs_path *path, int data_size,
1496 struct extent_buffer *left = path->nodes[0];
1497 struct extent_buffer *right;
1498 struct extent_buffer *upper;
1499 struct btrfs_disk_key disk_key;
1505 struct btrfs_item *item;
1513 slot = path->slots[1];
1514 if (!path->nodes[1]) {
1517 upper = path->nodes[1];
1518 if (slot >= btrfs_header_nritems(upper) - 1)
1521 right = read_tree_block(root, btrfs_node_blockptr(upper, slot + 1),
1523 free_space = btrfs_leaf_free_space(root, right);
1524 if (free_space < data_size + sizeof(struct btrfs_item)) {
1525 free_extent_buffer(right);
1529 /* cow and double check */
1530 ret = btrfs_cow_block(trans, root, right, upper,
1533 free_extent_buffer(right);
1536 free_space = btrfs_leaf_free_space(root, right);
1537 if (free_space < data_size + sizeof(struct btrfs_item)) {
1538 free_extent_buffer(right);
1542 left_nritems = btrfs_header_nritems(left);
1543 if (left_nritems == 0) {
1544 free_extent_buffer(right);
1553 i = left_nritems - 1;
1555 item = btrfs_item_nr(left, i);
1557 if (path->slots[0] == i)
1558 push_space += data_size + sizeof(*item);
1560 if (!left->map_token) {
1561 map_extent_buffer(left, (unsigned long)item,
1562 sizeof(struct btrfs_item),
1563 &left->map_token, &left->kaddr,
1564 &left->map_start, &left->map_len,
1568 this_item_size = btrfs_item_size(left, item);
1569 if (this_item_size + sizeof(*item) + push_space > free_space)
1572 push_space += this_item_size + sizeof(*item);
1577 if (left->map_token) {
1578 unmap_extent_buffer(left, left->map_token, KM_USER1);
1579 left->map_token = NULL;
1582 if (push_items == 0) {
1583 free_extent_buffer(right);
1587 if (!empty && push_items == left_nritems)
1590 /* push left to right */
1591 right_nritems = btrfs_header_nritems(right);
1593 push_space = btrfs_item_end_nr(left, left_nritems - push_items);
1594 push_space -= leaf_data_end(root, left);
1596 /* make room in the right data area */
1597 data_end = leaf_data_end(root, right);
1598 memmove_extent_buffer(right,
1599 btrfs_leaf_data(right) + data_end - push_space,
1600 btrfs_leaf_data(right) + data_end,
1601 BTRFS_LEAF_DATA_SIZE(root) - data_end);
1603 /* copy from the left data area */
1604 copy_extent_buffer(right, left, btrfs_leaf_data(right) +
1605 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1606 btrfs_leaf_data(left) + leaf_data_end(root, left),
1609 memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
1610 btrfs_item_nr_offset(0),
1611 right_nritems * sizeof(struct btrfs_item));
1613 /* copy the items from left to right */
1614 copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
1615 btrfs_item_nr_offset(left_nritems - push_items),
1616 push_items * sizeof(struct btrfs_item));
1618 /* update the item pointers */
1619 right_nritems += push_items;
1620 btrfs_set_header_nritems(right, right_nritems);
1621 push_space = BTRFS_LEAF_DATA_SIZE(root);
1622 for (i = 0; i < right_nritems; i++) {
1623 item = btrfs_item_nr(right, i);
1624 if (!right->map_token) {
1625 map_extent_buffer(right, (unsigned long)item,
1626 sizeof(struct btrfs_item),
1627 &right->map_token, &right->kaddr,
1628 &right->map_start, &right->map_len,
1631 push_space -= btrfs_item_size(right, item);
1632 btrfs_set_item_offset(right, item, push_space);
1635 if (right->map_token) {
1636 unmap_extent_buffer(right, right->map_token, KM_USER1);
1637 right->map_token = NULL;
1639 left_nritems -= push_items;
1640 btrfs_set_header_nritems(left, left_nritems);
1643 btrfs_mark_buffer_dirty(left);
1644 btrfs_mark_buffer_dirty(right);
1646 btrfs_item_key(right, &disk_key, 0);
1647 btrfs_set_node_key(upper, &disk_key, slot + 1);
1648 btrfs_mark_buffer_dirty(upper);
1650 /* then fixup the leaf pointer in the path */
1651 if (path->slots[0] >= left_nritems) {
1652 path->slots[0] -= left_nritems;
1653 free_extent_buffer(path->nodes[0]);
1654 path->nodes[0] = right;
1655 path->slots[1] += 1;
1657 free_extent_buffer(right);
1662 * push some data in the path leaf to the left, trying to free up at
1663 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1665 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1666 *root, struct btrfs_path *path, int data_size,
1669 struct btrfs_disk_key disk_key;
1670 struct extent_buffer *right = path->nodes[0];
1671 struct extent_buffer *left;
1677 struct btrfs_item *item;
1678 u32 old_left_nritems;
1684 u32 old_left_item_size;
1686 slot = path->slots[1];
1689 if (!path->nodes[1])
1692 right_nritems = btrfs_header_nritems(right);
1693 if (right_nritems == 0) {
1697 left = read_tree_block(root, btrfs_node_blockptr(path->nodes[1],
1698 slot - 1), root->leafsize);
1699 free_space = btrfs_leaf_free_space(root, left);
1700 if (free_space < data_size + sizeof(struct btrfs_item)) {
1701 free_extent_buffer(left);
1705 /* cow and double check */
1706 ret = btrfs_cow_block(trans, root, left,
1707 path->nodes[1], slot - 1, &left);
1709 /* we hit -ENOSPC, but it isn't fatal here */
1710 free_extent_buffer(left);
1714 free_space = btrfs_leaf_free_space(root, left);
1715 if (free_space < data_size + sizeof(struct btrfs_item)) {
1716 free_extent_buffer(left);
1723 nr = right_nritems - 1;
1725 for (i = 0; i < nr; i++) {
1726 item = btrfs_item_nr(right, i);
1727 if (!right->map_token) {
1728 map_extent_buffer(right, (unsigned long)item,
1729 sizeof(struct btrfs_item),
1730 &right->map_token, &right->kaddr,
1731 &right->map_start, &right->map_len,
1735 if (path->slots[0] == i)
1736 push_space += data_size + sizeof(*item);
1738 this_item_size = btrfs_item_size(right, item);
1739 if (this_item_size + sizeof(*item) + push_space > free_space)
1743 push_space += this_item_size + sizeof(*item);
1746 if (right->map_token) {
1747 unmap_extent_buffer(right, right->map_token, KM_USER1);
1748 right->map_token = NULL;
1751 if (push_items == 0) {
1752 free_extent_buffer(left);
1755 if (!empty && push_items == btrfs_header_nritems(right))
1758 /* push data from right to left */
1759 copy_extent_buffer(left, right,
1760 btrfs_item_nr_offset(btrfs_header_nritems(left)),
1761 btrfs_item_nr_offset(0),
1762 push_items * sizeof(struct btrfs_item));
1764 push_space = BTRFS_LEAF_DATA_SIZE(root) -
1765 btrfs_item_offset_nr(right, push_items -1);
1767 copy_extent_buffer(left, right, btrfs_leaf_data(left) +
1768 leaf_data_end(root, left) - push_space,
1769 btrfs_leaf_data(right) +
1770 btrfs_item_offset_nr(right, push_items - 1),
1772 old_left_nritems = btrfs_header_nritems(left);
1773 BUG_ON(old_left_nritems < 0);
1775 old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
1776 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1779 item = btrfs_item_nr(left, i);
1780 if (!left->map_token) {
1781 map_extent_buffer(left, (unsigned long)item,
1782 sizeof(struct btrfs_item),
1783 &left->map_token, &left->kaddr,
1784 &left->map_start, &left->map_len,
1788 ioff = btrfs_item_offset(left, item);
1789 btrfs_set_item_offset(left, item,
1790 ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
1792 btrfs_set_header_nritems(left, old_left_nritems + push_items);
1793 if (left->map_token) {
1794 unmap_extent_buffer(left, left->map_token, KM_USER1);
1795 left->map_token = NULL;
1798 /* fixup right node */
1799 if (push_items > right_nritems) {
1800 printk("push items %d nr %u\n", push_items, right_nritems);
1804 if (push_items < right_nritems) {
1805 push_space = btrfs_item_offset_nr(right, push_items - 1) -
1806 leaf_data_end(root, right);
1807 memmove_extent_buffer(right, btrfs_leaf_data(right) +
1808 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1809 btrfs_leaf_data(right) +
1810 leaf_data_end(root, right), push_space);
1812 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
1813 btrfs_item_nr_offset(push_items),
1814 (btrfs_header_nritems(right) - push_items) *
1815 sizeof(struct btrfs_item));
1817 right_nritems -= push_items;
1818 btrfs_set_header_nritems(right, right_nritems);
1819 push_space = BTRFS_LEAF_DATA_SIZE(root);
1820 for (i = 0; i < right_nritems; i++) {
1821 item = btrfs_item_nr(right, i);
1823 if (!right->map_token) {
1824 map_extent_buffer(right, (unsigned long)item,
1825 sizeof(struct btrfs_item),
1826 &right->map_token, &right->kaddr,
1827 &right->map_start, &right->map_len,
1831 push_space = push_space - btrfs_item_size(right, item);
1832 btrfs_set_item_offset(right, item, push_space);
1834 if (right->map_token) {
1835 unmap_extent_buffer(right, right->map_token, KM_USER1);
1836 right->map_token = NULL;
1839 btrfs_mark_buffer_dirty(left);
1841 btrfs_mark_buffer_dirty(right);
1843 btrfs_item_key(right, &disk_key, 0);
1844 wret = fixup_low_keys(trans, root, path, &disk_key, 1);
1848 /* then fixup the leaf pointer in the path */
1849 if (path->slots[0] < push_items) {
1850 path->slots[0] += old_left_nritems;
1851 free_extent_buffer(path->nodes[0]);
1852 path->nodes[0] = left;
1853 path->slots[1] -= 1;
1855 free_extent_buffer(left);
1856 path->slots[0] -= push_items;
1858 BUG_ON(path->slots[0] < 0);
1863 * split the path's leaf in two, making sure there is at least data_size
1864 * available for the resulting leaf level of the path.
1866 * returns 0 if all went well and < 0 on failure.
1868 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
1869 *root, struct btrfs_key *ins_key,
1870 struct btrfs_path *path, int data_size, int extend)
1873 struct extent_buffer *l;
1877 struct extent_buffer *right;
1878 int space_needed = data_size + sizeof(struct btrfs_item);
1885 int num_doubles = 0;
1886 struct btrfs_disk_key disk_key;
1889 space_needed = data_size;
1892 root_gen = trans->transid;
1896 /* first try to make some room by pushing left and right */
1897 if (ins_key->type != BTRFS_DIR_ITEM_KEY) {
1898 wret = push_leaf_right(trans, root, path, data_size, 0);
1903 wret = push_leaf_left(trans, root, path, data_size, 0);
1909 /* did the pushes work? */
1910 if (btrfs_leaf_free_space(root, l) >= space_needed)
1914 if (!path->nodes[1]) {
1915 ret = insert_new_root(trans, root, path, 1);
1922 slot = path->slots[0];
1923 nritems = btrfs_header_nritems(l);
1924 mid = (nritems + 1)/ 2;
1926 btrfs_item_key(l, &disk_key, 0);
1928 right = __btrfs_alloc_free_block(trans, root, root->leafsize,
1929 root->root_key.objectid,
1930 root_gen, disk_key.objectid, 0,
1933 return PTR_ERR(right);
1935 memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
1936 btrfs_set_header_bytenr(right, right->start);
1937 btrfs_set_header_generation(right, trans->transid);
1938 btrfs_set_header_owner(right, root->root_key.objectid);
1939 btrfs_set_header_level(right, 0);
1940 write_extent_buffer(right, root->fs_info->fsid,
1941 (unsigned long)btrfs_header_fsid(right),
1945 leaf_space_used(l, mid, nritems - mid) + space_needed >
1946 BTRFS_LEAF_DATA_SIZE(root)) {
1947 if (slot >= nritems) {
1948 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1949 btrfs_set_header_nritems(right, 0);
1950 wret = insert_ptr(trans, root, path,
1951 &disk_key, right->start,
1952 path->slots[1] + 1, 1);
1955 free_extent_buffer(path->nodes[0]);
1956 path->nodes[0] = right;
1958 path->slots[1] += 1;
1962 if (mid != nritems &&
1963 leaf_space_used(l, mid, nritems - mid) +
1964 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
1969 if (leaf_space_used(l, 0, mid + 1) + space_needed >
1970 BTRFS_LEAF_DATA_SIZE(root)) {
1971 if (!extend && slot == 0) {
1972 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1973 btrfs_set_header_nritems(right, 0);
1974 wret = insert_ptr(trans, root, path,
1980 free_extent_buffer(path->nodes[0]);
1981 path->nodes[0] = right;
1983 if (path->slots[1] == 0) {
1984 wret = fixup_low_keys(trans, root,
1985 path, &disk_key, 1);
1990 } else if (extend && slot == 0) {
1994 if (mid != nritems &&
1995 leaf_space_used(l, mid, nritems - mid) +
1996 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2002 nritems = nritems - mid;
2003 btrfs_set_header_nritems(right, nritems);
2004 data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
2006 copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
2007 btrfs_item_nr_offset(mid),
2008 nritems * sizeof(struct btrfs_item));
2010 copy_extent_buffer(right, l,
2011 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
2012 data_copy_size, btrfs_leaf_data(l) +
2013 leaf_data_end(root, l), data_copy_size);
2015 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
2016 btrfs_item_end_nr(l, mid);
2018 for (i = 0; i < nritems; i++) {
2019 struct btrfs_item *item = btrfs_item_nr(right, i);
2022 if (!right->map_token) {
2023 map_extent_buffer(right, (unsigned long)item,
2024 sizeof(struct btrfs_item),
2025 &right->map_token, &right->kaddr,
2026 &right->map_start, &right->map_len,
2030 ioff = btrfs_item_offset(right, item);
2031 btrfs_set_item_offset(right, item, ioff + rt_data_off);
2034 if (right->map_token) {
2035 unmap_extent_buffer(right, right->map_token, KM_USER1);
2036 right->map_token = NULL;
2039 btrfs_set_header_nritems(l, mid);
2041 btrfs_item_key(right, &disk_key, 0);
2042 wret = insert_ptr(trans, root, path, &disk_key, right->start,
2043 path->slots[1] + 1, 1);
2047 btrfs_mark_buffer_dirty(right);
2048 btrfs_mark_buffer_dirty(l);
2049 BUG_ON(path->slots[0] != slot);
2052 free_extent_buffer(path->nodes[0]);
2053 path->nodes[0] = right;
2054 path->slots[0] -= mid;
2055 path->slots[1] += 1;
2057 free_extent_buffer(right);
2059 BUG_ON(path->slots[0] < 0);
2062 BUG_ON(num_doubles != 0);
2069 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
2070 struct btrfs_root *root,
2071 struct btrfs_path *path,
2072 u32 new_size, int from_end)
2077 struct extent_buffer *leaf;
2078 struct btrfs_item *item;
2080 unsigned int data_end;
2081 unsigned int old_data_start;
2082 unsigned int old_size;
2083 unsigned int size_diff;
2086 slot_orig = path->slots[0];
2087 leaf = path->nodes[0];
2088 slot = path->slots[0];
2090 old_size = btrfs_item_size_nr(leaf, slot);
2091 if (old_size == new_size)
2094 nritems = btrfs_header_nritems(leaf);
2095 data_end = leaf_data_end(root, leaf);
2097 old_data_start = btrfs_item_offset_nr(leaf, slot);
2099 size_diff = old_size - new_size;
2102 BUG_ON(slot >= nritems);
2105 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2107 /* first correct the data pointers */
2108 for (i = slot; i < nritems; i++) {
2110 item = btrfs_item_nr(leaf, i);
2112 if (!leaf->map_token) {
2113 map_extent_buffer(leaf, (unsigned long)item,
2114 sizeof(struct btrfs_item),
2115 &leaf->map_token, &leaf->kaddr,
2116 &leaf->map_start, &leaf->map_len,
2120 ioff = btrfs_item_offset(leaf, item);
2121 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2124 if (leaf->map_token) {
2125 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2126 leaf->map_token = NULL;
2129 /* shift the data */
2131 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2132 data_end + size_diff, btrfs_leaf_data(leaf) +
2133 data_end, old_data_start + new_size - data_end);
2135 struct btrfs_disk_key disk_key;
2138 btrfs_item_key(leaf, &disk_key, slot);
2140 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
2142 struct btrfs_file_extent_item *fi;
2144 fi = btrfs_item_ptr(leaf, slot,
2145 struct btrfs_file_extent_item);
2146 fi = (struct btrfs_file_extent_item *)(
2147 (unsigned long)fi - size_diff);
2149 if (btrfs_file_extent_type(leaf, fi) ==
2150 BTRFS_FILE_EXTENT_INLINE) {
2151 ptr = btrfs_item_ptr_offset(leaf, slot);
2152 memmove_extent_buffer(leaf, ptr,
2154 offsetof(struct btrfs_file_extent_item,
2159 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2160 data_end + size_diff, btrfs_leaf_data(leaf) +
2161 data_end, old_data_start - data_end);
2163 offset = btrfs_disk_key_offset(&disk_key);
2164 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
2165 btrfs_set_item_key(leaf, &disk_key, slot);
2167 fixup_low_keys(trans, root, path, &disk_key, 1);
2170 item = btrfs_item_nr(leaf, slot);
2171 btrfs_set_item_size(leaf, item, new_size);
2172 btrfs_mark_buffer_dirty(leaf);
2175 if (btrfs_leaf_free_space(root, leaf) < 0) {
2176 btrfs_print_leaf(root, leaf);
2182 int btrfs_extend_item(struct btrfs_trans_handle *trans,
2183 struct btrfs_root *root, struct btrfs_path *path,
2189 struct extent_buffer *leaf;
2190 struct btrfs_item *item;
2192 unsigned int data_end;
2193 unsigned int old_data;
2194 unsigned int old_size;
2197 slot_orig = path->slots[0];
2198 leaf = path->nodes[0];
2200 nritems = btrfs_header_nritems(leaf);
2201 data_end = leaf_data_end(root, leaf);
2203 if (btrfs_leaf_free_space(root, leaf) < data_size) {
2204 btrfs_print_leaf(root, leaf);
2207 slot = path->slots[0];
2208 old_data = btrfs_item_end_nr(leaf, slot);
2211 if (slot >= nritems) {
2212 btrfs_print_leaf(root, leaf);
2213 printk("slot %d too large, nritems %d\n", slot, nritems);
2218 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2220 /* first correct the data pointers */
2221 for (i = slot; i < nritems; i++) {
2223 item = btrfs_item_nr(leaf, i);
2225 if (!leaf->map_token) {
2226 map_extent_buffer(leaf, (unsigned long)item,
2227 sizeof(struct btrfs_item),
2228 &leaf->map_token, &leaf->kaddr,
2229 &leaf->map_start, &leaf->map_len,
2232 ioff = btrfs_item_offset(leaf, item);
2233 btrfs_set_item_offset(leaf, item, ioff - data_size);
2236 if (leaf->map_token) {
2237 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2238 leaf->map_token = NULL;
2241 /* shift the data */
2242 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2243 data_end - data_size, btrfs_leaf_data(leaf) +
2244 data_end, old_data - data_end);
2246 data_end = old_data;
2247 old_size = btrfs_item_size_nr(leaf, slot);
2248 item = btrfs_item_nr(leaf, slot);
2249 btrfs_set_item_size(leaf, item, old_size + data_size);
2250 btrfs_mark_buffer_dirty(leaf);
2253 if (btrfs_leaf_free_space(root, leaf) < 0) {
2254 btrfs_print_leaf(root, leaf);
2261 * Given a key and some data, insert an item into the tree.
2262 * This does all the path init required, making room in the tree if needed.
2264 int btrfs_insert_empty_item(struct btrfs_trans_handle *trans,
2265 struct btrfs_root *root,
2266 struct btrfs_path *path,
2267 struct btrfs_key *cpu_key, u32 data_size)
2269 struct extent_buffer *leaf;
2270 struct btrfs_item *item;
2275 unsigned int data_end;
2276 struct btrfs_disk_key disk_key;
2278 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2280 /* create a root if there isn't one */
2284 ret = btrfs_search_slot(trans, root, cpu_key, path, data_size, 1);
2291 slot_orig = path->slots[0];
2292 leaf = path->nodes[0];
2294 nritems = btrfs_header_nritems(leaf);
2295 data_end = leaf_data_end(root, leaf);
2297 if (btrfs_leaf_free_space(root, leaf) <
2298 sizeof(struct btrfs_item) + data_size) {
2299 btrfs_print_leaf(root, leaf);
2300 printk("not enough freespace need %u have %d\n",
2301 data_size, btrfs_leaf_free_space(root, leaf));
2305 slot = path->slots[0];
2308 if (slot != nritems) {
2310 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2312 if (old_data < data_end) {
2313 btrfs_print_leaf(root, leaf);
2314 printk("slot %d old_data %d data_end %d\n",
2315 slot, old_data, data_end);
2319 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2321 /* first correct the data pointers */
2322 WARN_ON(leaf->map_token);
2323 for (i = slot; i < nritems; i++) {
2326 item = btrfs_item_nr(leaf, i);
2327 if (!leaf->map_token) {
2328 map_extent_buffer(leaf, (unsigned long)item,
2329 sizeof(struct btrfs_item),
2330 &leaf->map_token, &leaf->kaddr,
2331 &leaf->map_start, &leaf->map_len,
2335 ioff = btrfs_item_offset(leaf, item);
2336 btrfs_set_item_offset(leaf, item, ioff - data_size);
2338 if (leaf->map_token) {
2339 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2340 leaf->map_token = NULL;
2343 /* shift the items */
2344 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1),
2345 btrfs_item_nr_offset(slot),
2346 (nritems - slot) * sizeof(struct btrfs_item));
2348 /* shift the data */
2349 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2350 data_end - data_size, btrfs_leaf_data(leaf) +
2351 data_end, old_data - data_end);
2352 data_end = old_data;
2355 /* setup the item for the new data */
2356 btrfs_set_item_key(leaf, &disk_key, slot);
2357 item = btrfs_item_nr(leaf, slot);
2358 btrfs_set_item_offset(leaf, item, data_end - data_size);
2359 btrfs_set_item_size(leaf, item, data_size);
2360 btrfs_set_header_nritems(leaf, nritems + 1);
2361 btrfs_mark_buffer_dirty(leaf);
2365 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
2367 if (btrfs_leaf_free_space(root, leaf) < 0) {
2368 btrfs_print_leaf(root, leaf);
2376 * Given a key and some data, insert an item into the tree.
2377 * This does all the path init required, making room in the tree if needed.
2379 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2380 *root, struct btrfs_key *cpu_key, void *data, u32
2384 struct btrfs_path *path;
2385 struct extent_buffer *leaf;
2388 path = btrfs_alloc_path();
2390 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2392 leaf = path->nodes[0];
2393 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2394 write_extent_buffer(leaf, data, ptr, data_size);
2395 btrfs_mark_buffer_dirty(leaf);
2397 btrfs_free_path(path);
2402 * delete the pointer from a given node.
2404 * If the delete empties a node, the node is removed from the tree,
2405 * continuing all the way the root if required. The root is converted into
2406 * a leaf if all the nodes are emptied.
2408 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2409 struct btrfs_path *path, int level, int slot)
2411 struct extent_buffer *parent = path->nodes[level];
2416 nritems = btrfs_header_nritems(parent);
2417 if (slot != nritems -1) {
2418 memmove_extent_buffer(parent,
2419 btrfs_node_key_ptr_offset(slot),
2420 btrfs_node_key_ptr_offset(slot + 1),
2421 sizeof(struct btrfs_key_ptr) *
2422 (nritems - slot - 1));
2425 btrfs_set_header_nritems(parent, nritems);
2426 if (nritems == 0 && parent == root->node) {
2427 BUG_ON(btrfs_header_level(root->node) != 1);
2428 /* just turn the root into a leaf and break */
2429 btrfs_set_header_level(root->node, 0);
2430 } else if (slot == 0) {
2431 struct btrfs_disk_key disk_key;
2433 btrfs_node_key(parent, &disk_key, 0);
2434 wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
2438 btrfs_mark_buffer_dirty(parent);
2443 * delete the item at the leaf level in path. If that empties
2444 * the leaf, remove it from the tree
2446 int btrfs_del_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2447 struct btrfs_path *path)
2450 struct extent_buffer *leaf;
2451 struct btrfs_item *item;
2458 leaf = path->nodes[0];
2459 slot = path->slots[0];
2460 doff = btrfs_item_offset_nr(leaf, slot);
2461 dsize = btrfs_item_size_nr(leaf, slot);
2462 nritems = btrfs_header_nritems(leaf);
2464 if (slot != nritems - 1) {
2466 int data_end = leaf_data_end(root, leaf);
2468 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2470 btrfs_leaf_data(leaf) + data_end,
2473 for (i = slot + 1; i < nritems; i++) {
2476 item = btrfs_item_nr(leaf, i);
2477 if (!leaf->map_token) {
2478 map_extent_buffer(leaf, (unsigned long)item,
2479 sizeof(struct btrfs_item),
2480 &leaf->map_token, &leaf->kaddr,
2481 &leaf->map_start, &leaf->map_len,
2484 ioff = btrfs_item_offset(leaf, item);
2485 btrfs_set_item_offset(leaf, item, ioff + dsize);
2488 if (leaf->map_token) {
2489 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2490 leaf->map_token = NULL;
2493 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2494 btrfs_item_nr_offset(slot + 1),
2495 sizeof(struct btrfs_item) *
2496 (nritems - slot - 1));
2498 btrfs_set_header_nritems(leaf, nritems - 1);
2501 /* delete the leaf if we've emptied it */
2503 if (leaf == root->node) {
2504 btrfs_set_header_level(leaf, 0);
2506 u64 root_gen = btrfs_header_generation(path->nodes[1]);
2507 clean_tree_block(trans, root, leaf);
2508 wait_on_tree_block_writeback(root, leaf);
2509 wret = del_ptr(trans, root, path, 1, path->slots[1]);
2512 wret = btrfs_free_extent(trans, root,
2513 leaf->start, leaf->len,
2514 btrfs_header_owner(path->nodes[1]),
2520 int used = leaf_space_used(leaf, 0, nritems);
2522 struct btrfs_disk_key disk_key;
2524 btrfs_item_key(leaf, &disk_key, 0);
2525 wret = fixup_low_keys(trans, root, path,
2531 /* delete the leaf if it is mostly empty */
2532 if (used < BTRFS_LEAF_DATA_SIZE(root) / 3) {
2533 /* push_leaf_left fixes the path.
2534 * make sure the path still points to our leaf
2535 * for possible call to del_ptr below
2537 slot = path->slots[1];
2538 extent_buffer_get(leaf);
2540 wret = push_leaf_right(trans, root, path, 1, 1);
2541 if (wret < 0 && wret != -ENOSPC)
2544 if (path->nodes[0] == leaf &&
2545 btrfs_header_nritems(leaf)) {
2546 wret = push_leaf_left(trans, root, path, 1, 1);
2547 if (wret < 0 && wret != -ENOSPC)
2551 if (btrfs_header_nritems(leaf) == 0) {
2553 u64 bytenr = leaf->start;
2554 u32 blocksize = leaf->len;
2556 root_gen = btrfs_header_generation(
2559 clean_tree_block(trans, root, leaf);
2560 wait_on_tree_block_writeback(root, leaf);
2562 wret = del_ptr(trans, root, path, 1, slot);
2566 free_extent_buffer(leaf);
2567 wret = btrfs_free_extent(trans, root, bytenr,
2569 btrfs_header_owner(path->nodes[1]),
2574 btrfs_mark_buffer_dirty(leaf);
2575 free_extent_buffer(leaf);
2578 btrfs_mark_buffer_dirty(leaf);
2585 * walk up the tree as far as required to find the previous leaf.
2586 * returns 0 if it found something or 1 if there are no lesser leaves.
2587 * returns < 0 on io errors.
2589 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
2594 struct extent_buffer *c;
2595 struct extent_buffer *next = NULL;
2597 while(level < BTRFS_MAX_LEVEL) {
2598 if (!path->nodes[level])
2601 slot = path->slots[level];
2602 c = path->nodes[level];
2605 if (level == BTRFS_MAX_LEVEL)
2611 bytenr = btrfs_node_blockptr(c, slot);
2613 free_extent_buffer(next);
2615 if (path->reada < 0)
2616 reada_for_search(root, path, level, slot);
2618 next = read_tree_block(root, bytenr,
2619 btrfs_level_size(root, level - 1));
2622 path->slots[level] = slot;
2625 c = path->nodes[level];
2626 free_extent_buffer(c);
2627 path->nodes[level] = next;
2628 path->slots[level] = 0;
2632 reada_for_search(root, path, level, 0);
2633 next = read_tree_block(root, btrfs_node_blockptr(next, 0),
2634 btrfs_level_size(root, level - 1));
2640 * walk up the tree as far as required to find the next leaf.
2641 * returns 0 if it found something or 1 if there are no greater leaves.
2642 * returns < 0 on io errors.
2644 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
2649 struct extent_buffer *c;
2650 struct extent_buffer *next = NULL;
2652 while(level < BTRFS_MAX_LEVEL) {
2653 if (!path->nodes[level])
2656 slot = path->slots[level] + 1;
2657 c = path->nodes[level];
2658 if (slot >= btrfs_header_nritems(c)) {
2660 if (level == BTRFS_MAX_LEVEL)
2665 bytenr = btrfs_node_blockptr(c, slot);
2667 free_extent_buffer(next);
2670 reada_for_search(root, path, level, slot);
2672 next = read_tree_block(root, bytenr,
2673 btrfs_level_size(root, level -1));
2676 path->slots[level] = slot;
2679 c = path->nodes[level];
2680 free_extent_buffer(c);
2681 path->nodes[level] = next;
2682 path->slots[level] = 0;
2686 reada_for_search(root, path, level, 0);
2687 next = read_tree_block(root, btrfs_node_blockptr(next, 0),
2688 btrfs_level_size(root, level - 1));