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.
20 #include "transaction.h"
21 #include "print-tree.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, int extend);
28 static int push_node_left(struct btrfs_trans_handle *trans,
29 struct btrfs_root *root, struct extent_buffer *dst,
30 struct extent_buffer *src, int empty);
31 static int balance_node_right(struct btrfs_trans_handle *trans,
32 struct btrfs_root *root,
33 struct extent_buffer *dst_buf,
34 struct extent_buffer *src_buf);
35 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
36 struct btrfs_path *path, int level, int slot);
38 inline void btrfs_init_path(struct btrfs_path *p)
40 memset(p, 0, sizeof(*p));
43 struct btrfs_path *btrfs_alloc_path(void)
45 struct btrfs_path *path;
46 path = kmalloc(sizeof(struct btrfs_path), GFP_NOFS);
48 btrfs_init_path(path);
54 void btrfs_free_path(struct btrfs_path *p)
56 btrfs_release_path(NULL, p);
60 void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
63 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
66 free_extent_buffer(p->nodes[i]);
68 memset(p, 0, sizeof(*p));
71 static void add_root_to_dirty_list(struct btrfs_root *root)
73 if (root->track_dirty && list_empty(&root->dirty_list)) {
74 list_add(&root->dirty_list,
75 &root->fs_info->dirty_cowonly_roots);
79 int btrfs_copy_root(struct btrfs_trans_handle *trans,
80 struct btrfs_root *root,
81 struct extent_buffer *buf,
82 struct extent_buffer **cow_ret, u64 new_root_objectid)
84 struct extent_buffer *cow;
87 struct btrfs_root *new_root;
89 new_root = kmalloc(sizeof(*new_root), GFP_NOFS);
93 memcpy(new_root, root, sizeof(*new_root));
94 new_root->root_key.objectid = new_root_objectid;
96 WARN_ON(root->ref_cows && trans->transid !=
97 root->fs_info->running_transaction->transid);
98 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
100 level = btrfs_header_level(buf);
101 cow = btrfs_alloc_free_block(trans, new_root, buf->len, 0,
102 new_root_objectid, trans->transid,
103 level, buf->start, 0);
109 copy_extent_buffer(cow, buf, 0, 0, cow->len);
110 btrfs_set_header_bytenr(cow, cow->start);
111 btrfs_set_header_generation(cow, trans->transid);
112 btrfs_set_header_owner(cow, new_root_objectid);
113 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
115 write_extent_buffer(cow, root->fs_info->fsid,
116 (unsigned long)btrfs_header_fsid(cow),
119 WARN_ON(btrfs_header_generation(buf) > trans->transid);
120 ret = btrfs_inc_ref(trans, new_root, buf, cow, NULL);
126 btrfs_mark_buffer_dirty(cow);
131 int __btrfs_cow_block(struct btrfs_trans_handle *trans,
132 struct btrfs_root *root,
133 struct extent_buffer *buf,
134 struct extent_buffer *parent, int parent_slot,
135 struct extent_buffer **cow_ret,
136 u64 search_start, u64 empty_size)
139 struct extent_buffer *cow;
142 int different_trans = 0;
145 WARN_ON(root->ref_cows && trans->transid !=
146 root->fs_info->running_transaction->transid);
147 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
150 parent_start = parent->start;
154 level = btrfs_header_level(buf);
155 nritems = btrfs_header_nritems(buf);
156 cow = btrfs_alloc_free_block(trans, root, buf->len, parent_start,
157 root->root_key.objectid, trans->transid,
158 level, search_start, empty_size);
162 copy_extent_buffer(cow, buf, 0, 0, cow->len);
163 btrfs_set_header_bytenr(cow, cow->start);
164 btrfs_set_header_generation(cow, trans->transid);
165 btrfs_set_header_owner(cow, root->root_key.objectid);
166 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
168 write_extent_buffer(cow, root->fs_info->fsid,
169 (unsigned long)btrfs_header_fsid(cow),
172 WARN_ON(btrfs_header_generation(buf) > trans->transid);
173 if (btrfs_header_generation(buf) != trans->transid) {
175 ret = btrfs_inc_ref(trans, root, buf, cow, NULL);
179 ret = btrfs_update_ref(trans, root, buf, cow, 0, nritems);
182 clean_tree_block(trans, root, buf);
185 if (buf == root->node) {
187 extent_buffer_get(cow);
188 if (buf != root->commit_root) {
189 btrfs_free_extent(trans, root, buf->start,
190 buf->len, buf->start,
191 root->root_key.objectid,
192 btrfs_header_generation(buf),
195 free_extent_buffer(buf);
196 add_root_to_dirty_list(root);
198 btrfs_set_node_blockptr(parent, parent_slot,
200 WARN_ON(trans->transid == 0);
201 btrfs_set_node_ptr_generation(parent, parent_slot,
203 btrfs_mark_buffer_dirty(parent);
204 WARN_ON(btrfs_header_generation(parent) != trans->transid);
205 btrfs_free_extent(trans, root, buf->start, buf->len,
206 parent_start, btrfs_header_owner(parent),
207 btrfs_header_generation(parent), level, 1);
209 free_extent_buffer(buf);
210 btrfs_mark_buffer_dirty(cow);
215 int btrfs_cow_block(struct btrfs_trans_handle *trans,
216 struct btrfs_root *root, struct extent_buffer *buf,
217 struct extent_buffer *parent, int parent_slot,
218 struct extent_buffer **cow_ret)
223 if (trans->transaction != root->fs_info->running_transaction) {
224 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
225 root->fs_info->running_transaction->transid);
229 if (trans->transid != root->fs_info->generation) {
230 printk(KERN_CRIT "trans %llu running %llu\n",
231 (unsigned long long)trans->transid,
232 (unsigned long long)root->fs_info->generation);
235 if (btrfs_header_generation(buf) == trans->transid &&
236 !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
241 search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1);
242 ret = __btrfs_cow_block(trans, root, buf, parent,
243 parent_slot, cow_ret, search_start, 0);
248 static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
250 if (blocknr < other && other - (blocknr + blocksize) < 32768)
252 if (blocknr > other && blocknr - (other + blocksize) < 32768)
259 * compare two keys in a memcmp fashion
261 int btrfs_comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
265 btrfs_disk_key_to_cpu(&k1, disk);
267 if (k1.objectid > k2->objectid)
269 if (k1.objectid < k2->objectid)
271 if (k1.type > k2->type)
273 if (k1.type < k2->type)
275 if (k1.offset > k2->offset)
277 if (k1.offset < k2->offset)
284 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
285 struct btrfs_root *root, struct extent_buffer *parent,
286 int start_slot, int cache_only, u64 *last_ret,
287 struct btrfs_key *progress)
289 struct extent_buffer *cur;
290 struct extent_buffer *tmp;
293 u64 search_start = *last_ret;
303 int progress_passed = 0;
304 struct btrfs_disk_key disk_key;
306 parent_level = btrfs_header_level(parent);
307 if (cache_only && parent_level != 1)
310 if (trans->transaction != root->fs_info->running_transaction) {
311 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
312 root->fs_info->running_transaction->transid);
315 if (trans->transid != root->fs_info->generation) {
316 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
317 root->fs_info->generation);
321 parent_nritems = btrfs_header_nritems(parent);
322 blocksize = btrfs_level_size(root, parent_level - 1);
323 end_slot = parent_nritems;
325 if (parent_nritems == 1)
328 for (i = start_slot; i < end_slot; i++) {
331 if (!parent->map_token) {
332 map_extent_buffer(parent,
333 btrfs_node_key_ptr_offset(i),
334 sizeof(struct btrfs_key_ptr),
335 &parent->map_token, &parent->kaddr,
336 &parent->map_start, &parent->map_len,
339 btrfs_node_key(parent, &disk_key, i);
340 if (!progress_passed && comp_keys(&disk_key, progress) < 0)
344 blocknr = btrfs_node_blockptr(parent, i);
345 gen = btrfs_node_ptr_generation(parent, i);
347 last_block = blocknr;
350 other = btrfs_node_blockptr(parent, i - 1);
351 close = close_blocks(blocknr, other, blocksize);
353 if (close && i < end_slot - 2) {
354 other = btrfs_node_blockptr(parent, i + 1);
355 close = close_blocks(blocknr, other, blocksize);
358 last_block = blocknr;
361 if (parent->map_token) {
362 unmap_extent_buffer(parent, parent->map_token,
364 parent->map_token = NULL;
367 cur = btrfs_find_tree_block(root, blocknr, blocksize);
369 uptodate = btrfs_buffer_uptodate(cur, gen);
372 if (!cur || !uptodate) {
374 free_extent_buffer(cur);
378 cur = read_tree_block(root, blocknr,
380 } else if (!uptodate) {
381 btrfs_read_buffer(cur, gen);
384 if (search_start == 0)
385 search_start = last_block;
387 err = __btrfs_cow_block(trans, root, cur, parent, i,
390 (end_slot - i) * blocksize));
392 free_extent_buffer(cur);
395 search_start = tmp->start;
396 last_block = tmp->start;
397 *last_ret = search_start;
398 if (parent_level == 1)
399 btrfs_clear_buffer_defrag(tmp);
400 free_extent_buffer(tmp);
402 if (parent->map_token) {
403 unmap_extent_buffer(parent, parent->map_token,
405 parent->map_token = NULL;
412 * The leaf data grows from end-to-front in the node.
413 * this returns the address of the start of the last item,
414 * which is the stop of the leaf data stack
416 static inline unsigned int leaf_data_end(struct btrfs_root *root,
417 struct extent_buffer *leaf)
419 u32 nr = btrfs_header_nritems(leaf);
421 return BTRFS_LEAF_DATA_SIZE(root);
422 return btrfs_item_offset_nr(leaf, nr - 1);
425 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
428 struct extent_buffer *parent = NULL;
429 struct extent_buffer *node = path->nodes[level];
430 struct btrfs_disk_key parent_key;
431 struct btrfs_disk_key node_key;
434 struct btrfs_key cpukey;
435 u32 nritems = btrfs_header_nritems(node);
437 if (path->nodes[level + 1])
438 parent = path->nodes[level + 1];
440 slot = path->slots[level];
441 BUG_ON(nritems == 0);
443 parent_slot = path->slots[level + 1];
444 btrfs_node_key(parent, &parent_key, parent_slot);
445 btrfs_node_key(node, &node_key, 0);
446 BUG_ON(memcmp(&parent_key, &node_key,
447 sizeof(struct btrfs_disk_key)));
448 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
449 btrfs_header_bytenr(node));
451 BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
453 btrfs_node_key_to_cpu(node, &cpukey, slot - 1);
454 btrfs_node_key(node, &node_key, slot);
455 BUG_ON(btrfs_comp_keys(&node_key, &cpukey) <= 0);
457 if (slot < nritems - 1) {
458 btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
459 btrfs_node_key(node, &node_key, slot);
460 BUG_ON(btrfs_comp_keys(&node_key, &cpukey) >= 0);
465 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
468 struct extent_buffer *leaf = path->nodes[level];
469 struct extent_buffer *parent = NULL;
471 struct btrfs_key cpukey;
472 struct btrfs_disk_key parent_key;
473 struct btrfs_disk_key leaf_key;
474 int slot = path->slots[0];
476 u32 nritems = btrfs_header_nritems(leaf);
478 if (path->nodes[level + 1])
479 parent = path->nodes[level + 1];
485 parent_slot = path->slots[level + 1];
486 btrfs_node_key(parent, &parent_key, parent_slot);
487 btrfs_item_key(leaf, &leaf_key, 0);
489 BUG_ON(memcmp(&parent_key, &leaf_key,
490 sizeof(struct btrfs_disk_key)));
491 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
492 btrfs_header_bytenr(leaf));
495 for (i = 0; nritems > 1 && i < nritems - 2; i++) {
496 btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
497 btrfs_item_key(leaf, &leaf_key, i);
498 if (comp_keys(&leaf_key, &cpukey) >= 0) {
499 btrfs_print_leaf(root, leaf);
500 printk("slot %d offset bad key\n", i);
503 if (btrfs_item_offset_nr(leaf, i) !=
504 btrfs_item_end_nr(leaf, i + 1)) {
505 btrfs_print_leaf(root, leaf);
506 printk("slot %d offset bad\n", i);
510 if (btrfs_item_offset_nr(leaf, i) +
511 btrfs_item_size_nr(leaf, i) !=
512 BTRFS_LEAF_DATA_SIZE(root)) {
513 btrfs_print_leaf(root, leaf);
514 printk("slot %d first offset bad\n", i);
520 if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
521 btrfs_print_leaf(root, leaf);
522 printk("slot %d bad size \n", nritems - 1);
527 if (slot != 0 && slot < nritems - 1) {
528 btrfs_item_key(leaf, &leaf_key, slot);
529 btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
530 if (btrfs_comp_keys(&leaf_key, &cpukey) <= 0) {
531 btrfs_print_leaf(root, leaf);
532 printk("slot %d offset bad key\n", slot);
535 if (btrfs_item_offset_nr(leaf, slot - 1) !=
536 btrfs_item_end_nr(leaf, slot)) {
537 btrfs_print_leaf(root, leaf);
538 printk("slot %d offset bad\n", slot);
542 if (slot < nritems - 1) {
543 btrfs_item_key(leaf, &leaf_key, slot);
544 btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
545 BUG_ON(btrfs_comp_keys(&leaf_key, &cpukey) >= 0);
546 if (btrfs_item_offset_nr(leaf, slot) !=
547 btrfs_item_end_nr(leaf, slot + 1)) {
548 btrfs_print_leaf(root, leaf);
549 printk("slot %d offset bad\n", slot);
553 BUG_ON(btrfs_item_offset_nr(leaf, 0) +
554 btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
558 static int noinline check_block(struct btrfs_root *root,
559 struct btrfs_path *path, int level)
563 struct extent_buffer *buf = path->nodes[level];
565 if (memcmp_extent_buffer(buf, root->fs_info->fsid,
566 (unsigned long)btrfs_header_fsid(buf),
568 printk("warning bad block %Lu\n", buf->start);
573 return check_leaf(root, path, level);
574 return check_node(root, path, level);
578 * search for key in the extent_buffer. The items start at offset p,
579 * and they are item_size apart. There are 'max' items in p.
581 * the slot in the array is returned via slot, and it points to
582 * the place where you would insert key if it is not found in
585 * slot may point to max if the key is bigger than all of the keys
587 static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
588 int item_size, struct btrfs_key *key,
595 unsigned long offset;
596 struct btrfs_disk_key *tmp;
599 mid = (low + high) / 2;
600 offset = p + mid * item_size;
602 tmp = (struct btrfs_disk_key *)(eb->data + offset);
603 ret = btrfs_comp_keys(tmp, key);
619 * simple bin_search frontend that does the right thing for
622 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
623 int level, int *slot)
626 return generic_bin_search(eb,
627 offsetof(struct btrfs_leaf, items),
628 sizeof(struct btrfs_item),
629 key, btrfs_header_nritems(eb),
632 return generic_bin_search(eb,
633 offsetof(struct btrfs_node, ptrs),
634 sizeof(struct btrfs_key_ptr),
635 key, btrfs_header_nritems(eb),
641 static struct extent_buffer *read_node_slot(struct btrfs_root *root,
642 struct extent_buffer *parent, int slot)
644 int level = btrfs_header_level(parent);
647 if (slot >= btrfs_header_nritems(parent))
652 return read_tree_block(root, btrfs_node_blockptr(parent, slot),
653 btrfs_level_size(root, level - 1),
654 btrfs_node_ptr_generation(parent, slot));
657 static int balance_level(struct btrfs_trans_handle *trans,
658 struct btrfs_root *root,
659 struct btrfs_path *path, int level)
661 struct extent_buffer *right = NULL;
662 struct extent_buffer *mid;
663 struct extent_buffer *left = NULL;
664 struct extent_buffer *parent = NULL;
668 int orig_slot = path->slots[level];
669 int err_on_enospc = 0;
675 mid = path->nodes[level];
676 WARN_ON(btrfs_header_generation(mid) != trans->transid);
678 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
680 if (level < BTRFS_MAX_LEVEL - 1)
681 parent = path->nodes[level + 1];
682 pslot = path->slots[level + 1];
685 * deal with the case where there is only one pointer in the root
686 * by promoting the node below to a root
689 struct extent_buffer *child;
691 if (btrfs_header_nritems(mid) != 1)
694 /* promote the child to a root */
695 child = read_node_slot(root, mid, 0);
697 ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
702 ret = btrfs_update_extent_ref(trans, root, child->start,
703 mid->start, child->start,
704 root->root_key.objectid,
705 trans->transid, level - 1);
708 add_root_to_dirty_list(root);
709 path->nodes[level] = NULL;
710 clean_tree_block(trans, root, mid);
711 wait_on_tree_block_writeback(root, mid);
712 /* once for the path */
713 free_extent_buffer(mid);
714 ret = btrfs_free_extent(trans, root, mid->start, mid->len,
715 mid->start, root->root_key.objectid,
716 btrfs_header_generation(mid),
718 /* once for the root ptr */
719 free_extent_buffer(mid);
722 if (btrfs_header_nritems(mid) >
723 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
726 if (btrfs_header_nritems(mid) < 2)
729 left = read_node_slot(root, parent, pslot - 1);
731 wret = btrfs_cow_block(trans, root, left,
732 parent, pslot - 1, &left);
738 right = read_node_slot(root, parent, pslot + 1);
740 wret = btrfs_cow_block(trans, root, right,
741 parent, pslot + 1, &right);
748 /* first, try to make some room in the middle buffer */
750 orig_slot += btrfs_header_nritems(left);
751 wret = push_node_left(trans, root, left, mid, 1);
754 if (btrfs_header_nritems(mid) < 2)
759 * then try to empty the right most buffer into the middle
762 wret = push_node_left(trans, root, mid, right, 1);
763 if (wret < 0 && wret != -ENOSPC)
765 if (btrfs_header_nritems(right) == 0) {
766 u64 bytenr = right->start;
767 u64 generation = btrfs_header_generation(parent);
768 u32 blocksize = right->len;
770 clean_tree_block(trans, root, right);
771 wait_on_tree_block_writeback(root, right);
772 free_extent_buffer(right);
774 wret = del_ptr(trans, root, path, level + 1, pslot +
778 wret = btrfs_free_extent(trans, root, bytenr,
779 blocksize, parent->start,
780 btrfs_header_owner(parent),
781 generation, level, 1);
785 struct btrfs_disk_key right_key;
786 btrfs_node_key(right, &right_key, 0);
787 btrfs_set_node_key(parent, &right_key, pslot + 1);
788 btrfs_mark_buffer_dirty(parent);
791 if (btrfs_header_nritems(mid) == 1) {
793 * we're not allowed to leave a node with one item in the
794 * tree during a delete. A deletion from lower in the tree
795 * could try to delete the only pointer in this node.
796 * So, pull some keys from the left.
797 * There has to be a left pointer at this point because
798 * otherwise we would have pulled some pointers from the
802 wret = balance_node_right(trans, root, mid, left);
808 wret = push_node_left(trans, root, left, mid, 1);
814 if (btrfs_header_nritems(mid) == 0) {
815 /* we've managed to empty the middle node, drop it */
816 u64 root_gen = btrfs_header_generation(parent);
817 u64 bytenr = mid->start;
818 u32 blocksize = mid->len;
819 clean_tree_block(trans, root, mid);
820 wait_on_tree_block_writeback(root, mid);
821 free_extent_buffer(mid);
823 wret = del_ptr(trans, root, path, level + 1, pslot);
826 wret = btrfs_free_extent(trans, root, bytenr, blocksize,
828 btrfs_header_owner(parent),
833 /* update the parent key to reflect our changes */
834 struct btrfs_disk_key mid_key;
835 btrfs_node_key(mid, &mid_key, 0);
836 btrfs_set_node_key(parent, &mid_key, pslot);
837 btrfs_mark_buffer_dirty(parent);
840 /* update the path */
842 if (btrfs_header_nritems(left) > orig_slot) {
843 extent_buffer_get(left);
844 path->nodes[level] = left;
845 path->slots[level + 1] -= 1;
846 path->slots[level] = orig_slot;
848 free_extent_buffer(mid);
850 orig_slot -= btrfs_header_nritems(left);
851 path->slots[level] = orig_slot;
854 /* double check we haven't messed things up */
855 check_block(root, path, level);
857 btrfs_node_blockptr(path->nodes[level], path->slots[level]))
861 free_extent_buffer(right);
863 free_extent_buffer(left);
867 /* returns zero if the push worked, non-zero otherwise */
868 static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
869 struct btrfs_root *root,
870 struct btrfs_path *path, int level)
872 struct extent_buffer *right = NULL;
873 struct extent_buffer *mid;
874 struct extent_buffer *left = NULL;
875 struct extent_buffer *parent = NULL;
879 int orig_slot = path->slots[level];
885 mid = path->nodes[level];
886 WARN_ON(btrfs_header_generation(mid) != trans->transid);
887 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
889 if (level < BTRFS_MAX_LEVEL - 1)
890 parent = path->nodes[level + 1];
891 pslot = path->slots[level + 1];
896 left = read_node_slot(root, parent, pslot - 1);
898 /* first, try to make some room in the middle buffer */
901 left_nr = btrfs_header_nritems(left);
902 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
905 ret = btrfs_cow_block(trans, root, left, parent,
910 wret = push_node_left(trans, root,
917 struct btrfs_disk_key disk_key;
918 orig_slot += left_nr;
919 btrfs_node_key(mid, &disk_key, 0);
920 btrfs_set_node_key(parent, &disk_key, pslot);
921 btrfs_mark_buffer_dirty(parent);
922 if (btrfs_header_nritems(left) > orig_slot) {
923 path->nodes[level] = left;
924 path->slots[level + 1] -= 1;
925 path->slots[level] = orig_slot;
926 free_extent_buffer(mid);
929 btrfs_header_nritems(left);
930 path->slots[level] = orig_slot;
931 free_extent_buffer(left);
935 free_extent_buffer(left);
937 right= read_node_slot(root, parent, pslot + 1);
940 * then try to empty the right most buffer into the middle
944 right_nr = btrfs_header_nritems(right);
945 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
948 ret = btrfs_cow_block(trans, root, right,
954 wret = balance_node_right(trans, root,
961 struct btrfs_disk_key disk_key;
963 btrfs_node_key(right, &disk_key, 0);
964 btrfs_set_node_key(parent, &disk_key, pslot + 1);
965 btrfs_mark_buffer_dirty(parent);
967 if (btrfs_header_nritems(mid) <= orig_slot) {
968 path->nodes[level] = right;
969 path->slots[level + 1] += 1;
970 path->slots[level] = orig_slot -
971 btrfs_header_nritems(mid);
972 free_extent_buffer(mid);
974 free_extent_buffer(right);
978 free_extent_buffer(right);
984 * readahead one full node of leaves
986 static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
987 int level, int slot, u64 objectid)
989 struct extent_buffer *node;
990 struct btrfs_disk_key disk_key;
996 int direction = path->reada;
997 struct extent_buffer *eb;
1005 if (!path->nodes[level])
1008 node = path->nodes[level];
1009 search = btrfs_node_blockptr(node, slot);
1010 blocksize = btrfs_level_size(root, level - 1);
1011 eb = btrfs_find_tree_block(root, search, blocksize);
1013 free_extent_buffer(eb);
1017 highest_read = search;
1018 lowest_read = search;
1020 nritems = btrfs_header_nritems(node);
1023 if (direction < 0) {
1027 } else if (direction > 0) {
1032 if (path->reada < 0 && objectid) {
1033 btrfs_node_key(node, &disk_key, nr);
1034 if (btrfs_disk_key_objectid(&disk_key) != objectid)
1037 search = btrfs_node_blockptr(node, nr);
1038 if ((search >= lowest_read && search <= highest_read) ||
1039 (search < lowest_read && lowest_read - search <= 32768) ||
1040 (search > highest_read && search - highest_read <= 32768)) {
1041 readahead_tree_block(root, search, blocksize,
1042 btrfs_node_ptr_generation(node, nr));
1046 if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
1048 if(nread > (1024 * 1024) || nscan > 128)
1051 if (search < lowest_read)
1052 lowest_read = search;
1053 if (search > highest_read)
1054 highest_read = search;
1059 * look for key in the tree. path is filled in with nodes along the way
1060 * if key is found, we return zero and you can find the item in the leaf
1061 * level of the path (level 0)
1063 * If the key isn't found, the path points to the slot where it should
1064 * be inserted, and 1 is returned. If there are other errors during the
1065 * search a negative error number is returned.
1067 * if ins_len > 0, nodes and leaves will be split as we walk down the
1068 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
1071 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
1072 *root, struct btrfs_key *key, struct btrfs_path *p, int
1075 struct extent_buffer *b;
1079 int should_reada = p->reada;
1080 u8 lowest_level = 0;
1082 lowest_level = p->lowest_level;
1083 WARN_ON(lowest_level && ins_len);
1084 WARN_ON(p->nodes[0] != NULL);
1086 WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
1090 extent_buffer_get(b);
1092 level = btrfs_header_level(b);
1095 wret = btrfs_cow_block(trans, root, b,
1096 p->nodes[level + 1],
1097 p->slots[level + 1],
1100 free_extent_buffer(b);
1104 BUG_ON(!cow && ins_len);
1105 if (level != btrfs_header_level(b))
1107 level = btrfs_header_level(b);
1108 p->nodes[level] = b;
1109 ret = check_block(root, p, level);
1112 ret = bin_search(b, key, level, &slot);
1114 if (ret && slot > 0)
1116 p->slots[level] = slot;
1117 if (ins_len > 0 && btrfs_header_nritems(b) >=
1118 BTRFS_NODEPTRS_PER_BLOCK(root) - 3) {
1119 int sret = split_node(trans, root, p, level);
1123 b = p->nodes[level];
1124 slot = p->slots[level];
1125 } else if (ins_len < 0) {
1126 int sret = balance_level(trans, root, p,
1130 b = p->nodes[level];
1132 btrfs_release_path(NULL, p);
1135 slot = p->slots[level];
1136 BUG_ON(btrfs_header_nritems(b) == 1);
1138 /* this is only true while dropping a snapshot */
1139 if (level == lowest_level)
1143 reada_for_search(root, p, level, slot,
1146 b = read_node_slot(root, b, slot);
1148 p->slots[level] = slot;
1149 if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
1150 sizeof(struct btrfs_item) + ins_len) {
1151 int sret = split_leaf(trans, root, key,
1152 p, ins_len, ret == 0);
1164 * adjust the pointers going up the tree, starting at level
1165 * making sure the right key of each node is points to 'key'.
1166 * This is used after shifting pointers to the left, so it stops
1167 * fixing up pointers when a given leaf/node is not in slot 0 of the
1170 * If this fails to write a tree block, it returns -1, but continues
1171 * fixing up the blocks in ram so the tree is consistent.
1173 static int fixup_low_keys(struct btrfs_trans_handle *trans,
1174 struct btrfs_root *root, struct btrfs_path *path,
1175 struct btrfs_disk_key *key, int level)
1179 struct extent_buffer *t;
1181 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1182 int tslot = path->slots[i];
1183 if (!path->nodes[i])
1186 btrfs_set_node_key(t, key, tslot);
1187 btrfs_mark_buffer_dirty(path->nodes[i]);
1197 * This function isn't completely safe. It's the caller's responsibility
1198 * that the new key won't break the order
1200 int btrfs_set_item_key_safe(struct btrfs_trans_handle *trans,
1201 struct btrfs_root *root, struct btrfs_path *path,
1202 struct btrfs_key *new_key)
1204 struct btrfs_disk_key disk_key;
1205 struct extent_buffer *eb;
1208 eb = path->nodes[0];
1209 slot = path->slots[0];
1211 btrfs_item_key(eb, &disk_key, slot - 1);
1212 if (btrfs_comp_keys(&disk_key, new_key) >= 0)
1215 if (slot < btrfs_header_nritems(eb) - 1) {
1216 btrfs_item_key(eb, &disk_key, slot + 1);
1217 if (btrfs_comp_keys(&disk_key, new_key) <= 0)
1221 btrfs_cpu_key_to_disk(&disk_key, new_key);
1222 btrfs_set_item_key(eb, &disk_key, slot);
1223 btrfs_mark_buffer_dirty(eb);
1225 fixup_low_keys(trans, root, path, &disk_key, 1);
1230 * try to push data from one node into the next node left in the
1233 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1234 * error, and > 0 if there was no room in the left hand block.
1236 static int push_node_left(struct btrfs_trans_handle *trans,
1237 struct btrfs_root *root, struct extent_buffer *dst,
1238 struct extent_buffer *src, int empty)
1245 src_nritems = btrfs_header_nritems(src);
1246 dst_nritems = btrfs_header_nritems(dst);
1247 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1248 WARN_ON(btrfs_header_generation(src) != trans->transid);
1249 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1251 if (!empty && src_nritems <= 8)
1254 if (push_items <= 0) {
1259 push_items = min(src_nritems, push_items);
1260 if (push_items < src_nritems) {
1261 /* leave at least 8 pointers in the node if
1262 * we aren't going to empty it
1264 if (src_nritems - push_items < 8) {
1265 if (push_items <= 8)
1271 push_items = min(src_nritems - 8, push_items);
1273 copy_extent_buffer(dst, src,
1274 btrfs_node_key_ptr_offset(dst_nritems),
1275 btrfs_node_key_ptr_offset(0),
1276 push_items * sizeof(struct btrfs_key_ptr));
1278 if (push_items < src_nritems) {
1279 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1280 btrfs_node_key_ptr_offset(push_items),
1281 (src_nritems - push_items) *
1282 sizeof(struct btrfs_key_ptr));
1284 btrfs_set_header_nritems(src, src_nritems - push_items);
1285 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1286 btrfs_mark_buffer_dirty(src);
1287 btrfs_mark_buffer_dirty(dst);
1289 ret = btrfs_update_ref(trans, root, src, dst, dst_nritems, push_items);
1295 * try to push data from one node into the next node right in the
1298 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1299 * error, and > 0 if there was no room in the right hand block.
1301 * this will only push up to 1/2 the contents of the left node over
1303 static int balance_node_right(struct btrfs_trans_handle *trans,
1304 struct btrfs_root *root,
1305 struct extent_buffer *dst,
1306 struct extent_buffer *src)
1314 WARN_ON(btrfs_header_generation(src) != trans->transid);
1315 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1317 src_nritems = btrfs_header_nritems(src);
1318 dst_nritems = btrfs_header_nritems(dst);
1319 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1320 if (push_items <= 0) {
1324 if (src_nritems < 4) {
1328 max_push = src_nritems / 2 + 1;
1329 /* don't try to empty the node */
1330 if (max_push >= src_nritems) {
1334 if (max_push < push_items)
1335 push_items = max_push;
1337 memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1338 btrfs_node_key_ptr_offset(0),
1340 sizeof(struct btrfs_key_ptr));
1342 copy_extent_buffer(dst, src,
1343 btrfs_node_key_ptr_offset(0),
1344 btrfs_node_key_ptr_offset(src_nritems - push_items),
1345 push_items * sizeof(struct btrfs_key_ptr));
1347 btrfs_set_header_nritems(src, src_nritems - push_items);
1348 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1350 btrfs_mark_buffer_dirty(src);
1351 btrfs_mark_buffer_dirty(dst);
1353 ret = btrfs_update_ref(trans, root, src, dst, 0, push_items);
1359 * helper function to insert a new root level in the tree.
1360 * A new node is allocated, and a single item is inserted to
1361 * point to the existing root
1363 * returns zero on success or < 0 on failure.
1365 static int noinline insert_new_root(struct btrfs_trans_handle *trans,
1366 struct btrfs_root *root,
1367 struct btrfs_path *path, int level)
1370 struct extent_buffer *lower;
1371 struct extent_buffer *c;
1372 struct extent_buffer *old;
1373 struct btrfs_disk_key lower_key;
1376 BUG_ON(path->nodes[level]);
1377 BUG_ON(path->nodes[level-1] != root->node);
1379 lower = path->nodes[level-1];
1381 btrfs_item_key(lower, &lower_key, 0);
1383 btrfs_node_key(lower, &lower_key, 0);
1385 c = btrfs_alloc_free_block(trans, root, root->nodesize, 0,
1386 root->root_key.objectid,
1387 trans->transid, level,
1388 root->node->start, 0);
1392 memset_extent_buffer(c, 0, 0, root->nodesize);
1393 btrfs_set_header_nritems(c, 1);
1394 btrfs_set_header_level(c, level);
1395 btrfs_set_header_bytenr(c, c->start);
1396 btrfs_set_header_generation(c, trans->transid);
1397 btrfs_set_header_owner(c, root->root_key.objectid);
1399 write_extent_buffer(c, root->fs_info->fsid,
1400 (unsigned long)btrfs_header_fsid(c),
1403 write_extent_buffer(c, root->fs_info->chunk_tree_uuid,
1404 (unsigned long)btrfs_header_chunk_tree_uuid(c),
1407 btrfs_set_node_key(c, &lower_key, 0);
1408 btrfs_set_node_blockptr(c, 0, lower->start);
1409 lower_gen = btrfs_header_generation(lower);
1410 WARN_ON(lower_gen != trans->transid);
1412 btrfs_set_node_ptr_generation(c, 0, lower_gen);
1414 btrfs_mark_buffer_dirty(c);
1419 ret = btrfs_update_extent_ref(trans, root, lower->start,
1420 lower->start, c->start,
1421 root->root_key.objectid,
1422 trans->transid, level - 1);
1425 /* the super has an extra ref to root->node */
1426 free_extent_buffer(old);
1428 add_root_to_dirty_list(root);
1429 extent_buffer_get(c);
1430 path->nodes[level] = c;
1431 path->slots[level] = 0;
1436 * worker function to insert a single pointer in a node.
1437 * the node should have enough room for the pointer already
1439 * slot and level indicate where you want the key to go, and
1440 * blocknr is the block the key points to.
1442 * returns zero on success and < 0 on any error
1444 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1445 *root, struct btrfs_path *path, struct btrfs_disk_key
1446 *key, u64 bytenr, int slot, int level)
1448 struct extent_buffer *lower;
1451 BUG_ON(!path->nodes[level]);
1452 lower = path->nodes[level];
1453 nritems = btrfs_header_nritems(lower);
1456 if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1458 if (slot != nritems) {
1459 memmove_extent_buffer(lower,
1460 btrfs_node_key_ptr_offset(slot + 1),
1461 btrfs_node_key_ptr_offset(slot),
1462 (nritems - slot) * sizeof(struct btrfs_key_ptr));
1464 btrfs_set_node_key(lower, key, slot);
1465 btrfs_set_node_blockptr(lower, slot, bytenr);
1466 WARN_ON(trans->transid == 0);
1467 btrfs_set_node_ptr_generation(lower, slot, trans->transid);
1468 btrfs_set_header_nritems(lower, nritems + 1);
1469 btrfs_mark_buffer_dirty(lower);
1474 * split the node at the specified level in path in two.
1475 * The path is corrected to point to the appropriate node after the split
1477 * Before splitting this tries to make some room in the node by pushing
1478 * left and right, if either one works, it returns right away.
1480 * returns 0 on success and < 0 on failure
1482 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1483 *root, struct btrfs_path *path, int level)
1485 struct extent_buffer *c;
1486 struct extent_buffer *split;
1487 struct btrfs_disk_key disk_key;
1493 c = path->nodes[level];
1494 WARN_ON(btrfs_header_generation(c) != trans->transid);
1495 if (c == root->node) {
1496 /* trying to split the root, lets make a new one */
1497 ret = insert_new_root(trans, root, path, level + 1);
1501 ret = push_nodes_for_insert(trans, root, path, level);
1502 c = path->nodes[level];
1503 if (!ret && btrfs_header_nritems(c) <
1504 BTRFS_NODEPTRS_PER_BLOCK(root) - 3)
1510 c_nritems = btrfs_header_nritems(c);
1512 btrfs_node_key(c, &disk_key, 0);
1513 split = btrfs_alloc_free_block(trans, root, root->nodesize,
1514 path->nodes[level + 1]->start,
1515 root->root_key.objectid,
1516 trans->transid, level, c->start, 0);
1518 return PTR_ERR(split);
1520 btrfs_set_header_flags(split, btrfs_header_flags(c));
1521 btrfs_set_header_level(split, btrfs_header_level(c));
1522 btrfs_set_header_bytenr(split, split->start);
1523 btrfs_set_header_generation(split, trans->transid);
1524 btrfs_set_header_owner(split, root->root_key.objectid);
1525 btrfs_set_header_flags(split, 0);
1526 write_extent_buffer(split, root->fs_info->fsid,
1527 (unsigned long)btrfs_header_fsid(split),
1529 write_extent_buffer(split, root->fs_info->chunk_tree_uuid,
1530 (unsigned long)btrfs_header_chunk_tree_uuid(split),
1533 mid = (c_nritems + 1) / 2;
1535 copy_extent_buffer(split, c,
1536 btrfs_node_key_ptr_offset(0),
1537 btrfs_node_key_ptr_offset(mid),
1538 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1539 btrfs_set_header_nritems(split, c_nritems - mid);
1540 btrfs_set_header_nritems(c, mid);
1543 btrfs_mark_buffer_dirty(c);
1544 btrfs_mark_buffer_dirty(split);
1546 btrfs_node_key(split, &disk_key, 0);
1547 wret = insert_ptr(trans, root, path, &disk_key, split->start,
1548 path->slots[level + 1] + 1,
1553 ret = btrfs_update_ref(trans, root, c, split, 0, c_nritems - mid);
1556 if (path->slots[level] >= mid) {
1557 path->slots[level] -= mid;
1558 free_extent_buffer(c);
1559 path->nodes[level] = split;
1560 path->slots[level + 1] += 1;
1562 free_extent_buffer(split);
1568 * how many bytes are required to store the items in a leaf. start
1569 * and nr indicate which items in the leaf to check. This totals up the
1570 * space used both by the item structs and the item data
1572 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1575 int nritems = btrfs_header_nritems(l);
1576 int end = min(nritems, start + nr) - 1;
1580 data_len = btrfs_item_end_nr(l, start);
1581 data_len = data_len - btrfs_item_offset_nr(l, end);
1582 data_len += sizeof(struct btrfs_item) * nr;
1583 WARN_ON(data_len < 0);
1588 * The space between the end of the leaf items and
1589 * the start of the leaf data. IOW, how much room
1590 * the leaf has left for both items and data
1592 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
1594 int nritems = btrfs_header_nritems(leaf);
1596 ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
1598 printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
1599 ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
1600 leaf_space_used(leaf, 0, nritems), nritems);
1606 * push some data in the path leaf to the right, trying to free up at
1607 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1609 * returns 1 if the push failed because the other node didn't have enough
1610 * room, 0 if everything worked out and < 0 if there were major errors.
1612 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1613 *root, struct btrfs_path *path, int data_size,
1616 struct extent_buffer *left = path->nodes[0];
1617 struct extent_buffer *right;
1618 struct extent_buffer *upper;
1619 struct btrfs_disk_key disk_key;
1625 struct btrfs_item *item;
1633 slot = path->slots[1];
1634 if (!path->nodes[1]) {
1637 upper = path->nodes[1];
1638 if (slot >= btrfs_header_nritems(upper) - 1)
1641 right = read_node_slot(root, upper, slot + 1);
1642 free_space = btrfs_leaf_free_space(root, right);
1643 if (free_space < data_size + sizeof(struct btrfs_item)) {
1644 free_extent_buffer(right);
1648 /* cow and double check */
1649 ret = btrfs_cow_block(trans, root, right, upper,
1652 free_extent_buffer(right);
1655 free_space = btrfs_leaf_free_space(root, right);
1656 if (free_space < data_size + sizeof(struct btrfs_item)) {
1657 free_extent_buffer(right);
1661 left_nritems = btrfs_header_nritems(left);
1662 if (left_nritems == 0) {
1663 free_extent_buffer(right);
1672 i = left_nritems - 1;
1674 item = btrfs_item_nr(left, i);
1676 if (path->slots[0] == i)
1677 push_space += data_size + sizeof(*item);
1679 this_item_size = btrfs_item_size(left, item);
1680 if (this_item_size + sizeof(*item) + push_space > free_space)
1683 push_space += this_item_size + sizeof(*item);
1689 if (push_items == 0) {
1690 free_extent_buffer(right);
1694 if (!empty && push_items == left_nritems)
1697 /* push left to right */
1698 right_nritems = btrfs_header_nritems(right);
1700 push_space = btrfs_item_end_nr(left, left_nritems - push_items);
1701 push_space -= leaf_data_end(root, left);
1703 /* make room in the right data area */
1704 data_end = leaf_data_end(root, right);
1705 memmove_extent_buffer(right,
1706 btrfs_leaf_data(right) + data_end - push_space,
1707 btrfs_leaf_data(right) + data_end,
1708 BTRFS_LEAF_DATA_SIZE(root) - data_end);
1710 /* copy from the left data area */
1711 copy_extent_buffer(right, left, btrfs_leaf_data(right) +
1712 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1713 btrfs_leaf_data(left) + leaf_data_end(root, left),
1716 memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
1717 btrfs_item_nr_offset(0),
1718 right_nritems * sizeof(struct btrfs_item));
1720 /* copy the items from left to right */
1721 copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
1722 btrfs_item_nr_offset(left_nritems - push_items),
1723 push_items * sizeof(struct btrfs_item));
1725 /* update the item pointers */
1726 right_nritems += push_items;
1727 btrfs_set_header_nritems(right, right_nritems);
1728 push_space = BTRFS_LEAF_DATA_SIZE(root);
1729 for (i = 0; i < right_nritems; i++) {
1730 item = btrfs_item_nr(right, i);
1731 push_space -= btrfs_item_size(right, item);
1732 btrfs_set_item_offset(right, item, push_space);
1735 left_nritems -= push_items;
1736 btrfs_set_header_nritems(left, left_nritems);
1739 btrfs_mark_buffer_dirty(left);
1740 btrfs_mark_buffer_dirty(right);
1742 btrfs_item_key(right, &disk_key, 0);
1743 btrfs_set_node_key(upper, &disk_key, slot + 1);
1744 btrfs_mark_buffer_dirty(upper);
1746 ret = btrfs_update_ref(trans, root, left, right, 0, push_items);
1749 /* then fixup the leaf pointer in the path */
1750 if (path->slots[0] >= left_nritems) {
1751 path->slots[0] -= left_nritems;
1752 free_extent_buffer(path->nodes[0]);
1753 path->nodes[0] = right;
1754 path->slots[1] += 1;
1756 free_extent_buffer(right);
1761 * push some data in the path leaf to the left, trying to free up at
1762 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1764 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1765 *root, struct btrfs_path *path, int data_size,
1768 struct btrfs_disk_key disk_key;
1769 struct extent_buffer *right = path->nodes[0];
1770 struct extent_buffer *left;
1776 struct btrfs_item *item;
1777 u32 old_left_nritems;
1783 u32 old_left_item_size;
1785 slot = path->slots[1];
1788 if (!path->nodes[1])
1791 right_nritems = btrfs_header_nritems(right);
1792 if (right_nritems == 0) {
1796 left = read_node_slot(root, path->nodes[1], slot - 1);
1797 free_space = btrfs_leaf_free_space(root, left);
1798 if (free_space < data_size + sizeof(struct btrfs_item)) {
1799 free_extent_buffer(left);
1803 /* cow and double check */
1804 ret = btrfs_cow_block(trans, root, left,
1805 path->nodes[1], slot - 1, &left);
1807 /* we hit -ENOSPC, but it isn't fatal here */
1808 free_extent_buffer(left);
1812 free_space = btrfs_leaf_free_space(root, left);
1813 if (free_space < data_size + sizeof(struct btrfs_item)) {
1814 free_extent_buffer(left);
1821 nr = right_nritems - 1;
1823 for (i = 0; i < nr; i++) {
1824 item = btrfs_item_nr(right, i);
1826 if (path->slots[0] == i)
1827 push_space += data_size + sizeof(*item);
1829 this_item_size = btrfs_item_size(right, item);
1830 if (this_item_size + sizeof(*item) + push_space > free_space)
1834 push_space += this_item_size + sizeof(*item);
1837 if (push_items == 0) {
1838 free_extent_buffer(left);
1841 if (!empty && push_items == btrfs_header_nritems(right))
1844 /* push data from right to left */
1845 copy_extent_buffer(left, right,
1846 btrfs_item_nr_offset(btrfs_header_nritems(left)),
1847 btrfs_item_nr_offset(0),
1848 push_items * sizeof(struct btrfs_item));
1850 push_space = BTRFS_LEAF_DATA_SIZE(root) -
1851 btrfs_item_offset_nr(right, push_items -1);
1853 copy_extent_buffer(left, right, btrfs_leaf_data(left) +
1854 leaf_data_end(root, left) - push_space,
1855 btrfs_leaf_data(right) +
1856 btrfs_item_offset_nr(right, push_items - 1),
1858 old_left_nritems = btrfs_header_nritems(left);
1859 BUG_ON(old_left_nritems < 0);
1861 old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
1862 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1865 item = btrfs_item_nr(left, i);
1866 ioff = btrfs_item_offset(left, item);
1867 btrfs_set_item_offset(left, item,
1868 ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
1870 btrfs_set_header_nritems(left, old_left_nritems + push_items);
1872 /* fixup right node */
1873 if (push_items > right_nritems) {
1874 printk("push items %d nr %u\n", push_items, right_nritems);
1878 if (push_items < right_nritems) {
1879 push_space = btrfs_item_offset_nr(right, push_items - 1) -
1880 leaf_data_end(root, right);
1881 memmove_extent_buffer(right, btrfs_leaf_data(right) +
1882 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1883 btrfs_leaf_data(right) +
1884 leaf_data_end(root, right), push_space);
1886 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
1887 btrfs_item_nr_offset(push_items),
1888 (btrfs_header_nritems(right) - push_items) *
1889 sizeof(struct btrfs_item));
1891 right_nritems -= push_items;
1892 btrfs_set_header_nritems(right, right_nritems);
1893 push_space = BTRFS_LEAF_DATA_SIZE(root);
1894 for (i = 0; i < right_nritems; i++) {
1895 item = btrfs_item_nr(right, i);
1896 push_space = push_space - btrfs_item_size(right, item);
1897 btrfs_set_item_offset(right, item, push_space);
1900 btrfs_mark_buffer_dirty(left);
1902 btrfs_mark_buffer_dirty(right);
1904 btrfs_item_key(right, &disk_key, 0);
1905 wret = fixup_low_keys(trans, root, path, &disk_key, 1);
1909 ret = btrfs_update_ref(trans, root, right, left,
1910 old_left_nritems, push_items);
1913 /* then fixup the leaf pointer in the path */
1914 if (path->slots[0] < push_items) {
1915 path->slots[0] += old_left_nritems;
1916 free_extent_buffer(path->nodes[0]);
1917 path->nodes[0] = left;
1918 path->slots[1] -= 1;
1920 free_extent_buffer(left);
1921 path->slots[0] -= push_items;
1923 BUG_ON(path->slots[0] < 0);
1928 * split the path's leaf in two, making sure there is at least data_size
1929 * available for the resulting leaf level of the path.
1931 * returns 0 if all went well and < 0 on failure.
1933 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
1934 *root, struct btrfs_key *ins_key,
1935 struct btrfs_path *path, int data_size, int extend)
1937 struct extent_buffer *l;
1941 struct extent_buffer *right;
1942 int space_needed = data_size + sizeof(struct btrfs_item);
1949 int num_doubles = 0;
1950 struct btrfs_disk_key disk_key;
1953 space_needed = data_size;
1955 /* first try to make some room by pushing left and right */
1956 if (ins_key->type != BTRFS_DIR_ITEM_KEY) {
1957 wret = push_leaf_right(trans, root, path, data_size, 0);
1962 wret = push_leaf_left(trans, root, path, data_size, 0);
1968 /* did the pushes work? */
1969 if (btrfs_leaf_free_space(root, l) >= space_needed)
1973 if (!path->nodes[1]) {
1974 ret = insert_new_root(trans, root, path, 1);
1981 slot = path->slots[0];
1982 nritems = btrfs_header_nritems(l);
1983 mid = (nritems + 1)/ 2;
1985 right = btrfs_alloc_free_block(trans, root, root->leafsize,
1986 path->nodes[1]->start,
1987 root->root_key.objectid,
1988 trans->transid, 0, l->start, 0);
1989 if (IS_ERR(right)) {
1991 return PTR_ERR(right);
1994 memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
1995 btrfs_set_header_bytenr(right, right->start);
1996 btrfs_set_header_generation(right, trans->transid);
1997 btrfs_set_header_owner(right, root->root_key.objectid);
1998 btrfs_set_header_level(right, 0);
1999 write_extent_buffer(right, root->fs_info->fsid,
2000 (unsigned long)btrfs_header_fsid(right),
2003 write_extent_buffer(right, root->fs_info->chunk_tree_uuid,
2004 (unsigned long)btrfs_header_chunk_tree_uuid(right),
2008 leaf_space_used(l, mid, nritems - mid) + space_needed >
2009 BTRFS_LEAF_DATA_SIZE(root)) {
2010 if (slot >= nritems) {
2011 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2012 btrfs_set_header_nritems(right, 0);
2013 wret = insert_ptr(trans, root, path,
2014 &disk_key, right->start,
2015 path->slots[1] + 1, 1);
2018 free_extent_buffer(path->nodes[0]);
2019 path->nodes[0] = right;
2021 path->slots[1] += 1;
2025 if (mid != nritems &&
2026 leaf_space_used(l, mid, nritems - mid) +
2027 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2032 if (leaf_space_used(l, 0, mid + 1) + space_needed >
2033 BTRFS_LEAF_DATA_SIZE(root)) {
2034 if (!extend && slot == 0) {
2035 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2036 btrfs_set_header_nritems(right, 0);
2037 wret = insert_ptr(trans, root, path,
2043 free_extent_buffer(path->nodes[0]);
2044 path->nodes[0] = right;
2046 if (path->slots[1] == 0) {
2047 wret = fixup_low_keys(trans, root,
2048 path, &disk_key, 1);
2053 } else if (extend && slot == 0) {
2057 if (mid != nritems &&
2058 leaf_space_used(l, mid, nritems - mid) +
2059 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2065 nritems = nritems - mid;
2066 btrfs_set_header_nritems(right, nritems);
2067 data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
2069 copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
2070 btrfs_item_nr_offset(mid),
2071 nritems * sizeof(struct btrfs_item));
2073 copy_extent_buffer(right, l,
2074 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
2075 data_copy_size, btrfs_leaf_data(l) +
2076 leaf_data_end(root, l), data_copy_size);
2078 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
2079 btrfs_item_end_nr(l, mid);
2081 for (i = 0; i < nritems; i++) {
2082 struct btrfs_item *item = btrfs_item_nr(right, i);
2083 u32 ioff = btrfs_item_offset(right, item);
2084 btrfs_set_item_offset(right, item, ioff + rt_data_off);
2087 btrfs_set_header_nritems(l, mid);
2089 btrfs_item_key(right, &disk_key, 0);
2090 wret = insert_ptr(trans, root, path, &disk_key, right->start,
2091 path->slots[1] + 1, 1);
2095 btrfs_mark_buffer_dirty(right);
2096 btrfs_mark_buffer_dirty(l);
2097 BUG_ON(path->slots[0] != slot);
2099 ret = btrfs_update_ref(trans, root, l, right, 0, nritems);
2103 free_extent_buffer(path->nodes[0]);
2104 path->nodes[0] = right;
2105 path->slots[0] -= mid;
2106 path->slots[1] += 1;
2108 free_extent_buffer(right);
2110 BUG_ON(path->slots[0] < 0);
2113 BUG_ON(num_doubles != 0);
2120 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
2121 struct btrfs_root *root,
2122 struct btrfs_path *path,
2123 u32 new_size, int from_end)
2128 struct extent_buffer *leaf;
2129 struct btrfs_item *item;
2131 unsigned int data_end;
2132 unsigned int old_data_start;
2133 unsigned int old_size;
2134 unsigned int size_diff;
2137 slot_orig = path->slots[0];
2138 leaf = path->nodes[0];
2139 slot = path->slots[0];
2141 old_size = btrfs_item_size_nr(leaf, slot);
2142 if (old_size == new_size)
2145 nritems = btrfs_header_nritems(leaf);
2146 data_end = leaf_data_end(root, leaf);
2148 old_data_start = btrfs_item_offset_nr(leaf, slot);
2150 size_diff = old_size - new_size;
2153 BUG_ON(slot >= nritems);
2156 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2158 /* first correct the data pointers */
2159 for (i = slot; i < nritems; i++) {
2161 item = btrfs_item_nr(leaf, i);
2162 ioff = btrfs_item_offset(leaf, item);
2163 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2166 /* shift the data */
2168 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2169 data_end + size_diff, btrfs_leaf_data(leaf) +
2170 data_end, old_data_start + new_size - data_end);
2172 struct btrfs_disk_key disk_key;
2175 btrfs_item_key(leaf, &disk_key, slot);
2177 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
2179 struct btrfs_file_extent_item *fi;
2181 fi = btrfs_item_ptr(leaf, slot,
2182 struct btrfs_file_extent_item);
2183 fi = (struct btrfs_file_extent_item *)(
2184 (unsigned long)fi - size_diff);
2186 if (btrfs_file_extent_type(leaf, fi) ==
2187 BTRFS_FILE_EXTENT_INLINE) {
2188 ptr = btrfs_item_ptr_offset(leaf, slot);
2189 memmove_extent_buffer(leaf, ptr,
2191 offsetof(struct btrfs_file_extent_item,
2196 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2197 data_end + size_diff, btrfs_leaf_data(leaf) +
2198 data_end, old_data_start - data_end);
2200 offset = btrfs_disk_key_offset(&disk_key);
2201 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
2202 btrfs_set_item_key(leaf, &disk_key, slot);
2204 fixup_low_keys(trans, root, path, &disk_key, 1);
2207 item = btrfs_item_nr(leaf, slot);
2208 btrfs_set_item_size(leaf, item, new_size);
2209 btrfs_mark_buffer_dirty(leaf);
2212 if (btrfs_leaf_free_space(root, leaf) < 0) {
2213 btrfs_print_leaf(root, leaf);
2219 int btrfs_extend_item(struct btrfs_trans_handle *trans,
2220 struct btrfs_root *root, struct btrfs_path *path,
2226 struct extent_buffer *leaf;
2227 struct btrfs_item *item;
2229 unsigned int data_end;
2230 unsigned int old_data;
2231 unsigned int old_size;
2234 slot_orig = path->slots[0];
2235 leaf = path->nodes[0];
2237 nritems = btrfs_header_nritems(leaf);
2238 data_end = leaf_data_end(root, leaf);
2240 if (btrfs_leaf_free_space(root, leaf) < data_size) {
2241 btrfs_print_leaf(root, leaf);
2244 slot = path->slots[0];
2245 old_data = btrfs_item_end_nr(leaf, slot);
2248 if (slot >= nritems) {
2249 btrfs_print_leaf(root, leaf);
2250 printk("slot %d too large, nritems %d\n", slot, nritems);
2255 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2257 /* first correct the data pointers */
2258 for (i = slot; i < nritems; i++) {
2260 item = btrfs_item_nr(leaf, i);
2261 ioff = btrfs_item_offset(leaf, item);
2262 btrfs_set_item_offset(leaf, item, ioff - data_size);
2265 /* shift the data */
2266 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2267 data_end - data_size, btrfs_leaf_data(leaf) +
2268 data_end, old_data - data_end);
2270 data_end = old_data;
2271 old_size = btrfs_item_size_nr(leaf, slot);
2272 item = btrfs_item_nr(leaf, slot);
2273 btrfs_set_item_size(leaf, item, old_size + data_size);
2274 btrfs_mark_buffer_dirty(leaf);
2277 if (btrfs_leaf_free_space(root, leaf) < 0) {
2278 btrfs_print_leaf(root, leaf);
2285 * Given a key and some data, insert an item into the tree.
2286 * This does all the path init required, making room in the tree if needed.
2288 int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
2289 struct btrfs_root *root,
2290 struct btrfs_path *path,
2291 struct btrfs_key *cpu_key, u32 *data_size,
2294 struct extent_buffer *leaf;
2295 struct btrfs_item *item;
2303 unsigned int data_end;
2304 struct btrfs_disk_key disk_key;
2306 for (i = 0; i < nr; i++) {
2307 total_data += data_size[i];
2310 /* create a root if there isn't one */
2314 total_size = total_data + (nr - 1) * sizeof(struct btrfs_item);
2315 ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
2322 slot_orig = path->slots[0];
2323 leaf = path->nodes[0];
2325 nritems = btrfs_header_nritems(leaf);
2326 data_end = leaf_data_end(root, leaf);
2328 if (btrfs_leaf_free_space(root, leaf) <
2329 sizeof(struct btrfs_item) + total_size) {
2330 btrfs_print_leaf(root, leaf);
2331 printk("not enough freespace need %u have %d\n",
2332 total_size, btrfs_leaf_free_space(root, leaf));
2336 slot = path->slots[0];
2339 if (slot != nritems) {
2341 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2343 if (old_data < data_end) {
2344 btrfs_print_leaf(root, leaf);
2345 printk("slot %d old_data %d data_end %d\n",
2346 slot, old_data, data_end);
2350 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2352 /* first correct the data pointers */
2353 for (i = slot; i < nritems; i++) {
2356 item = btrfs_item_nr(leaf, i);
2357 ioff = btrfs_item_offset(leaf, item);
2358 btrfs_set_item_offset(leaf, item, ioff - total_data);
2361 /* shift the items */
2362 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
2363 btrfs_item_nr_offset(slot),
2364 (nritems - slot) * sizeof(struct btrfs_item));
2366 /* shift the data */
2367 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2368 data_end - total_data, btrfs_leaf_data(leaf) +
2369 data_end, old_data - data_end);
2370 data_end = old_data;
2373 /* setup the item for the new data */
2374 for (i = 0; i < nr; i++) {
2375 btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
2376 btrfs_set_item_key(leaf, &disk_key, slot + i);
2377 item = btrfs_item_nr(leaf, slot + i);
2378 btrfs_set_item_offset(leaf, item, data_end - data_size[i]);
2379 data_end -= data_size[i];
2380 btrfs_set_item_size(leaf, item, data_size[i]);
2382 btrfs_set_header_nritems(leaf, nritems + nr);
2383 btrfs_mark_buffer_dirty(leaf);
2387 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2388 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
2391 if (btrfs_leaf_free_space(root, leaf) < 0) {
2392 btrfs_print_leaf(root, leaf);
2401 * Given a key and some data, insert an item into the tree.
2402 * This does all the path init required, making room in the tree if needed.
2404 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2405 *root, struct btrfs_key *cpu_key, void *data, u32
2409 struct btrfs_path *path;
2410 struct extent_buffer *leaf;
2413 path = btrfs_alloc_path();
2415 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2417 leaf = path->nodes[0];
2418 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2419 write_extent_buffer(leaf, data, ptr, data_size);
2420 btrfs_mark_buffer_dirty(leaf);
2422 btrfs_free_path(path);
2427 * delete the pointer from a given node.
2429 * If the delete empties a node, the node is removed from the tree,
2430 * continuing all the way the root if required. The root is converted into
2431 * a leaf if all the nodes are emptied.
2433 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2434 struct btrfs_path *path, int level, int slot)
2436 struct extent_buffer *parent = path->nodes[level];
2441 nritems = btrfs_header_nritems(parent);
2442 if (slot != nritems -1) {
2443 memmove_extent_buffer(parent,
2444 btrfs_node_key_ptr_offset(slot),
2445 btrfs_node_key_ptr_offset(slot + 1),
2446 sizeof(struct btrfs_key_ptr) *
2447 (nritems - slot - 1));
2450 btrfs_set_header_nritems(parent, nritems);
2451 if (nritems == 0 && parent == root->node) {
2452 BUG_ON(btrfs_header_level(root->node) != 1);
2453 /* just turn the root into a leaf and break */
2454 btrfs_set_header_level(root->node, 0);
2455 } else if (slot == 0) {
2456 struct btrfs_disk_key disk_key;
2458 btrfs_node_key(parent, &disk_key, 0);
2459 wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
2463 btrfs_mark_buffer_dirty(parent);
2468 * delete the item at the leaf level in path. If that empties
2469 * the leaf, remove it from the tree
2471 int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2472 struct btrfs_path *path, int slot, int nr)
2474 struct extent_buffer *leaf;
2475 struct btrfs_item *item;
2483 leaf = path->nodes[0];
2484 last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
2486 for (i = 0; i < nr; i++)
2487 dsize += btrfs_item_size_nr(leaf, slot + i);
2489 nritems = btrfs_header_nritems(leaf);
2491 if (slot + nr != nritems) {
2493 int data_end = leaf_data_end(root, leaf);
2495 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2497 btrfs_leaf_data(leaf) + data_end,
2498 last_off - data_end);
2500 for (i = slot + nr; i < nritems; i++) {
2503 item = btrfs_item_nr(leaf, i);
2504 ioff = btrfs_item_offset(leaf, item);
2505 btrfs_set_item_offset(leaf, item, ioff + dsize);
2508 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2509 btrfs_item_nr_offset(slot + nr),
2510 sizeof(struct btrfs_item) *
2511 (nritems - slot - nr));
2513 btrfs_set_header_nritems(leaf, nritems - nr);
2516 /* delete the leaf if we've emptied it */
2518 if (leaf == root->node) {
2519 btrfs_set_header_level(leaf, 0);
2521 u64 root_gen = btrfs_header_generation(path->nodes[1]);
2522 clean_tree_block(trans, root, leaf);
2523 wait_on_tree_block_writeback(root, leaf);
2524 wret = del_ptr(trans, root, path, 1, path->slots[1]);
2527 wret = btrfs_free_extent(trans, root,
2528 leaf->start, leaf->len,
2529 path->nodes[1]->start,
2530 btrfs_header_owner(path->nodes[1]),
2536 int used = leaf_space_used(leaf, 0, nritems);
2538 struct btrfs_disk_key disk_key;
2540 btrfs_item_key(leaf, &disk_key, 0);
2541 wret = fixup_low_keys(trans, root, path,
2547 /* delete the leaf if it is mostly empty */
2548 if (used < BTRFS_LEAF_DATA_SIZE(root) / 4) {
2549 /* push_leaf_left fixes the path.
2550 * make sure the path still points to our leaf
2551 * for possible call to del_ptr below
2553 slot = path->slots[1];
2554 extent_buffer_get(leaf);
2556 wret = push_leaf_left(trans, root, path, 1, 1);
2557 if (wret < 0 && wret != -ENOSPC)
2560 if (path->nodes[0] == leaf &&
2561 btrfs_header_nritems(leaf)) {
2562 wret = push_leaf_right(trans, root, path, 1, 1);
2563 if (wret < 0 && wret != -ENOSPC)
2567 if (btrfs_header_nritems(leaf) == 0) {
2569 u64 bytenr = leaf->start;
2570 u32 blocksize = leaf->len;
2572 root_gen = btrfs_header_generation(
2575 clean_tree_block(trans, root, leaf);
2576 wait_on_tree_block_writeback(root, leaf);
2578 wret = del_ptr(trans, root, path, 1, slot);
2582 free_extent_buffer(leaf);
2583 wret = btrfs_free_extent(trans, root, bytenr,
2584 blocksize, path->nodes[1]->start,
2585 btrfs_header_owner(path->nodes[1]),
2590 btrfs_mark_buffer_dirty(leaf);
2591 free_extent_buffer(leaf);
2594 btrfs_mark_buffer_dirty(leaf);
2601 * walk up the tree as far as required to find the previous leaf.
2602 * returns 0 if it found something or 1 if there are no lesser leaves.
2603 * returns < 0 on io errors.
2605 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
2609 struct extent_buffer *c;
2610 struct extent_buffer *next = NULL;
2612 while(level < BTRFS_MAX_LEVEL) {
2613 if (!path->nodes[level])
2616 slot = path->slots[level];
2617 c = path->nodes[level];
2620 if (level == BTRFS_MAX_LEVEL)
2627 free_extent_buffer(next);
2629 next = read_node_slot(root, c, slot);
2632 path->slots[level] = slot;
2635 c = path->nodes[level];
2636 free_extent_buffer(c);
2637 slot = btrfs_header_nritems(next);
2640 path->nodes[level] = next;
2641 path->slots[level] = slot;
2644 next = read_node_slot(root, next, slot);
2650 * walk up the tree as far as required to find the next leaf.
2651 * returns 0 if it found something or 1 if there are no greater leaves.
2652 * returns < 0 on io errors.
2654 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
2658 struct extent_buffer *c;
2659 struct extent_buffer *next = NULL;
2661 while(level < BTRFS_MAX_LEVEL) {
2662 if (!path->nodes[level])
2665 slot = path->slots[level] + 1;
2666 c = path->nodes[level];
2667 if (slot >= btrfs_header_nritems(c)) {
2669 if (level == BTRFS_MAX_LEVEL)
2675 free_extent_buffer(next);
2678 reada_for_search(root, path, level, slot, 0);
2680 next = read_node_slot(root, c, slot);
2683 path->slots[level] = slot;
2686 c = path->nodes[level];
2687 free_extent_buffer(c);
2688 path->nodes[level] = next;
2689 path->slots[level] = 0;
2693 reada_for_search(root, path, level, 0, 0);
2694 next = read_node_slot(root, next, 0);
2699 int btrfs_previous_item(struct btrfs_root *root,
2700 struct btrfs_path *path, u64 min_objectid,
2703 struct btrfs_key found_key;
2704 struct extent_buffer *leaf;
2708 if (path->slots[0] == 0) {
2709 ret = btrfs_prev_leaf(root, path);
2715 leaf = path->nodes[0];
2716 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2717 if (found_key.type == type)