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/highmem.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);
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)
80 struct extent_buffer *cow;
82 int different_trans = 0;
84 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
86 cow = btrfs_alloc_free_block(trans, root, buf->len,
87 search_start, empty_size);
91 cow->alloc_addr = (unsigned long)__builtin_return_address(0);
93 copy_extent_buffer(cow, buf, 0, 0, cow->len);
94 btrfs_set_header_bytenr(cow, cow->start);
95 btrfs_set_header_generation(cow, trans->transid);
96 btrfs_set_header_owner(cow, root->root_key.objectid);
98 WARN_ON(btrfs_header_generation(buf) > trans->transid);
99 if (btrfs_header_generation(buf) != trans->transid) {
101 ret = btrfs_inc_ref(trans, root, buf);
105 clean_tree_block(trans, root, buf);
108 if (buf == root->node) {
110 extent_buffer_get(cow);
111 if (buf != root->commit_root) {
112 btrfs_free_extent(trans, root, buf->start,
115 free_extent_buffer(buf);
117 btrfs_set_node_blockptr(parent, parent_slot,
119 btrfs_mark_buffer_dirty(parent);
120 WARN_ON(btrfs_header_generation(parent) != trans->transid);
121 btrfs_free_extent(trans, root, buf->start, buf->len, 1);
123 free_extent_buffer(buf);
124 btrfs_mark_buffer_dirty(cow);
129 int btrfs_cow_block(struct btrfs_trans_handle *trans,
130 struct btrfs_root *root, struct extent_buffer *buf,
131 struct extent_buffer *parent, int parent_slot,
132 struct extent_buffer **cow_ret)
136 if (trans->transaction != root->fs_info->running_transaction) {
137 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
138 root->fs_info->running_transaction->transid);
141 if (trans->transid != root->fs_info->generation) {
142 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
143 root->fs_info->generation);
146 if (btrfs_header_generation(buf) == trans->transid) {
151 search_start = buf->start & ~((u64)BTRFS_BLOCK_GROUP_SIZE - 1);
152 ret = __btrfs_cow_block(trans, root, buf, parent,
153 parent_slot, cow_ret, search_start, 0);
154 (*cow_ret)->alloc_addr = (unsigned long)__builtin_return_address(0);
159 static int close_blocks(u64 blocknr, u64 other)
161 if (blocknr < other && other - blocknr < 8)
163 if (blocknr > other && blocknr - other < 8)
168 static int should_defrag_leaf(struct extent_buffer *eb)
171 struct btrfs_leaf *leaf = btrfs_buffer_leaf(eb);
172 struct btrfs_disk_key *key;
175 if (buffer_defrag(bh))
178 nritems = btrfs_header_nritems(&leaf->header);
182 key = &leaf->items[0].key;
183 if (btrfs_disk_key_type(key) == BTRFS_DIR_ITEM_KEY)
186 key = &leaf->items[nritems-1].key;
187 if (btrfs_disk_key_type(key) == BTRFS_DIR_ITEM_KEY)
190 key = &leaf->items[nritems/2].key;
191 if (btrfs_disk_key_type(key) == BTRFS_DIR_ITEM_KEY)
198 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
199 struct btrfs_root *root, struct extent_buffer *parent,
200 int cache_only, u64 *last_ret)
204 struct btrfs_node *parent_node;
205 struct extent_buffer *cur_eb;
206 struct extent_buffer *tmp_eb;
208 u64 search_start = *last_ret;
218 if (trans->transaction != root->fs_info->running_transaction) {
219 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
220 root->fs_info->running_transaction->transid);
223 if (trans->transid != root->fs_info->generation) {
224 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
225 root->fs_info->generation);
228 if (buffer_defrag_done(parent))
231 parent_node = btrfs_buffer_node(parent);
232 parent_nritems = btrfs_header_nritems(&parent_node->header);
233 parent_level = btrfs_header_level(&parent_node->header);
236 end_slot = parent_nritems;
238 if (parent_nritems == 1)
241 for (i = start_slot; i < end_slot; i++) {
243 blocknr = btrfs_node_blockptr(parent_node, i);
245 last_block = blocknr;
247 other = btrfs_node_blockptr(parent_node, i - 1);
248 close = close_blocks(blocknr, other);
250 if (close && i < end_slot - 1) {
251 other = btrfs_node_blockptr(parent_node, i + 1);
252 close = close_blocks(blocknr, other);
255 last_block = blocknr;
259 cur_bh = btrfs_find_tree_block(root, blocknr);
260 if (!cur_bh || !buffer_uptodate(cur_bh) ||
261 buffer_locked(cur_bh) ||
262 (parent_level != 1 && !buffer_defrag(cur_bh)) ||
263 (parent_level == 1 && !should_defrag_leaf(cur_bh))) {
268 if (!cur_bh || !buffer_uptodate(cur_bh) ||
269 buffer_locked(cur_bh)) {
271 cur_bh = read_tree_block(root, blocknr);
274 if (search_start == 0)
275 search_start = last_block & ~((u64)65535);
277 err = __btrfs_cow_block(trans, root, cur_bh, parent, i,
278 &tmp_bh, search_start,
279 min(8, end_slot - i));
284 search_start = bh_blocknr(tmp_bh);
285 *last_ret = search_start;
286 if (parent_level == 1)
287 clear_buffer_defrag(tmp_bh);
288 set_buffer_defrag_done(tmp_bh);
296 * The leaf data grows from end-to-front in the node.
297 * this returns the address of the start of the last item,
298 * which is the stop of the leaf data stack
300 static inline unsigned int leaf_data_end(struct btrfs_root *root,
301 struct extent_buffer *leaf)
303 u32 nr = btrfs_header_nritems(leaf);
305 return BTRFS_LEAF_DATA_SIZE(root);
306 return btrfs_item_offset_nr(leaf, nr - 1);
310 * compare two keys in a memcmp fashion
312 static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
316 btrfs_disk_key_to_cpu(&k1, disk);
318 if (k1.objectid > k2->objectid)
320 if (k1.objectid < k2->objectid)
322 if (k1.type > k2->type)
324 if (k1.type < k2->type)
326 if (k1.offset > k2->offset)
328 if (k1.offset < k2->offset)
333 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
336 struct extent_buffer *parent = NULL;
337 struct extent_buffer *node = path->nodes[level];
338 struct btrfs_disk_key parent_key;
339 struct btrfs_disk_key node_key;
342 struct btrfs_key cpukey;
343 u32 nritems = btrfs_header_nritems(node);
345 if (path->nodes[level + 1])
346 parent = path->nodes[level + 1];
348 slot = path->slots[level];
349 BUG_ON(nritems == 0);
351 parent_slot = path->slots[level + 1];
352 btrfs_node_key(parent, &parent_key, parent_slot);
353 btrfs_node_key(node, &node_key, 0);
354 BUG_ON(memcmp(&parent_key, &node_key,
355 sizeof(struct btrfs_disk_key)));
356 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
357 btrfs_header_bytenr(node));
359 BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
361 btrfs_node_key_to_cpu(node, &cpukey, slot - 1);
362 btrfs_node_key(node, &node_key, slot);
363 BUG_ON(comp_keys(&node_key, &cpukey) <= 0);
365 if (slot < nritems - 1) {
366 btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
367 btrfs_node_key(node, &node_key, slot);
368 BUG_ON(comp_keys(&node_key, &cpukey) >= 0);
373 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
376 struct extent_buffer *leaf = path->nodes[level];
377 struct extent_buffer *parent = NULL;
379 struct btrfs_key cpukey;
380 struct btrfs_disk_key parent_key;
381 struct btrfs_disk_key leaf_key;
382 int slot = path->slots[0];
384 u32 nritems = btrfs_header_nritems(leaf);
386 if (path->nodes[level + 1])
387 parent = path->nodes[level + 1];
393 parent_slot = path->slots[level + 1];
394 btrfs_node_key(parent, &parent_key, parent_slot);
395 btrfs_item_key(leaf, &leaf_key, 0);
397 BUG_ON(memcmp(&parent_key, &leaf_key,
398 sizeof(struct btrfs_disk_key)));
399 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
400 btrfs_header_bytenr(leaf));
403 for (i = 0; nritems > 1 && i < nritems - 2; i++) {
404 btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
405 btrfs_item_key(leaf, &leaf_key, i);
406 if (comp_keys(&leaf_key, &cpukey) >= 0) {
407 btrfs_print_leaf(root, leaf);
408 printk("slot %d offset bad key\n", i);
411 if (btrfs_item_offset_nr(leaf, i) !=
412 btrfs_item_end_nr(leaf, i + 1)) {
413 btrfs_print_leaf(root, leaf);
414 printk("slot %d offset bad\n", i);
418 if (btrfs_item_offset_nr(leaf, i) +
419 btrfs_item_size_nr(leaf, i) !=
420 BTRFS_LEAF_DATA_SIZE(root)) {
421 btrfs_print_leaf(root, leaf);
422 printk("slot %d first offset bad\n", i);
428 if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
429 btrfs_print_leaf(root, leaf);
430 printk("slot %d bad size \n", nritems - 1);
435 if (slot != 0 && slot < nritems - 1) {
436 btrfs_item_key(leaf, &leaf_key, slot);
437 btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
438 if (comp_keys(&leaf_key, &cpukey) <= 0) {
439 btrfs_print_leaf(root, leaf);
440 printk("slot %d offset bad key\n", slot);
443 if (btrfs_item_offset_nr(leaf, slot - 1) !=
444 btrfs_item_end_nr(leaf, slot)) {
445 btrfs_print_leaf(root, leaf);
446 printk("slot %d offset bad\n", slot);
450 if (slot < nritems - 1) {
451 btrfs_item_key(leaf, &leaf_key, slot);
452 btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
453 BUG_ON(comp_keys(&leaf_key, &cpukey) >= 0);
454 if (btrfs_item_offset_nr(leaf, slot) !=
455 btrfs_item_end_nr(leaf, slot + 1)) {
456 btrfs_print_leaf(root, leaf);
457 printk("slot %d offset bad\n", slot);
461 BUG_ON(btrfs_item_offset_nr(leaf, 0) +
462 btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
466 static int check_block(struct btrfs_root *root, struct btrfs_path *path,
470 struct extent_buffer *buf = path->nodes[level];
472 if (memcmp_extent_buffer(buf, root->fs_info->fsid,
473 (unsigned long)btrfs_header_fsid(buf),
475 printk("warning bad block %Lu\n", buf->start);
480 return check_leaf(root, path, level);
481 return check_node(root, path, level);
485 * search for key in the extent_buffer. The items start at offset p,
486 * and they are item_size apart. There are 'max' items in p.
488 * the slot in the array is returned via slot, and it points to
489 * the place where you would insert key if it is not found in
492 * slot may point to max if the key is bigger than all of the keys
494 static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
495 int item_size, struct btrfs_key *key,
502 struct btrfs_disk_key *tmp = NULL;
503 struct btrfs_disk_key unaligned;
504 unsigned long offset;
505 char *map_token = NULL;
507 unsigned long map_start = 0;
508 unsigned long map_len = 0;
512 mid = (low + high) / 2;
513 offset = p + mid * item_size;
515 if (!map_token || offset < map_start ||
516 (offset + sizeof(struct btrfs_disk_key)) >
517 map_start + map_len) {
519 unmap_extent_buffer(eb, map_token, KM_USER0);
522 err = map_extent_buffer(eb, offset,
523 sizeof(struct btrfs_disk_key),
525 &map_start, &map_len, KM_USER0);
528 tmp = (struct btrfs_disk_key *)(kaddr + offset -
531 read_extent_buffer(eb, &unaligned,
532 offset, sizeof(unaligned));
537 tmp = (struct btrfs_disk_key *)(kaddr + offset -
540 ret = comp_keys(tmp, key);
549 unmap_extent_buffer(eb, map_token, KM_USER0);
555 unmap_extent_buffer(eb, map_token, KM_USER0);
560 * simple bin_search frontend that does the right thing for
563 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
564 int level, int *slot)
567 return generic_bin_search(eb,
568 offsetof(struct btrfs_leaf, items),
569 sizeof(struct btrfs_item),
570 key, btrfs_header_nritems(eb),
573 return generic_bin_search(eb,
574 offsetof(struct btrfs_node, ptrs),
575 sizeof(struct btrfs_key_ptr),
576 key, btrfs_header_nritems(eb),
582 static struct extent_buffer *read_node_slot(struct btrfs_root *root,
583 struct extent_buffer *parent, int slot)
587 if (slot >= btrfs_header_nritems(parent))
589 return read_tree_block(root, btrfs_node_blockptr(parent, slot),
590 btrfs_level_size(root, btrfs_header_level(parent) - 1));
593 static int balance_level(struct btrfs_trans_handle *trans, struct btrfs_root
594 *root, struct btrfs_path *path, int level)
596 struct extent_buffer *right = NULL;
597 struct extent_buffer *mid;
598 struct extent_buffer *left = NULL;
599 struct extent_buffer *parent = NULL;
603 int orig_slot = path->slots[level];
604 int err_on_enospc = 0;
610 mid = path->nodes[level];
611 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
613 if (level < BTRFS_MAX_LEVEL - 1)
614 parent = path->nodes[level + 1];
615 pslot = path->slots[level + 1];
618 * deal with the case where there is only one pointer in the root
619 * by promoting the node below to a root
622 struct extent_buffer *child;
624 if (btrfs_header_nritems(mid) != 1)
627 /* promote the child to a root */
628 child = read_node_slot(root, mid, 0);
631 path->nodes[level] = NULL;
632 clean_tree_block(trans, root, mid);
633 wait_on_tree_block_writeback(root, mid);
634 /* once for the path */
635 free_extent_buffer(mid);
636 ret = btrfs_free_extent(trans, root, mid->start, mid->len, 1);
637 /* once for the root ptr */
638 free_extent_buffer(mid);
641 if (btrfs_header_nritems(mid) >
642 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
645 if (btrfs_header_nritems(mid) < 2)
648 left = read_node_slot(root, parent, pslot - 1);
650 wret = btrfs_cow_block(trans, root, left,
651 parent, pslot - 1, &left);
657 right = read_node_slot(root, parent, pslot + 1);
659 wret = btrfs_cow_block(trans, root, right,
660 parent, pslot + 1, &right);
667 /* first, try to make some room in the middle buffer */
669 orig_slot += btrfs_header_nritems(left);
670 wret = push_node_left(trans, root, left, mid);
673 if (btrfs_header_nritems(mid) < 2)
678 * then try to empty the right most buffer into the middle
681 wret = push_node_left(trans, root, mid, right);
682 if (wret < 0 && wret != -ENOSPC)
684 if (btrfs_header_nritems(right) == 0) {
685 u64 bytenr = right->start;
686 u32 blocksize = right->len;
688 clean_tree_block(trans, root, right);
689 wait_on_tree_block_writeback(root, right);
690 free_extent_buffer(right);
692 wret = del_ptr(trans, root, path, level + 1, pslot +
696 wret = btrfs_free_extent(trans, root, bytenr,
701 struct btrfs_disk_key right_key;
702 btrfs_node_key(right, &right_key, 0);
703 btrfs_set_node_key(parent, &right_key, pslot + 1);
704 btrfs_mark_buffer_dirty(parent);
707 if (btrfs_header_nritems(mid) == 1) {
709 * we're not allowed to leave a node with one item in the
710 * tree during a delete. A deletion from lower in the tree
711 * could try to delete the only pointer in this node.
712 * So, pull some keys from the left.
713 * There has to be a left pointer at this point because
714 * otherwise we would have pulled some pointers from the
718 wret = balance_node_right(trans, root, mid, left);
725 if (btrfs_header_nritems(mid) == 0) {
726 /* we've managed to empty the middle node, drop it */
727 u64 bytenr = mid->start;
728 u32 blocksize = mid->len;
729 clean_tree_block(trans, root, mid);
730 wait_on_tree_block_writeback(root, mid);
731 free_extent_buffer(mid);
733 wret = del_ptr(trans, root, path, level + 1, pslot);
736 wret = btrfs_free_extent(trans, root, bytenr, blocksize, 1);
740 /* update the parent key to reflect our changes */
741 struct btrfs_disk_key mid_key;
742 btrfs_node_key(mid, &mid_key, 0);
743 btrfs_set_node_key(parent, &mid_key, pslot);
744 btrfs_mark_buffer_dirty(parent);
747 /* update the path */
749 if (btrfs_header_nritems(left) > orig_slot) {
750 extent_buffer_get(left);
751 path->nodes[level] = left;
752 path->slots[level + 1] -= 1;
753 path->slots[level] = orig_slot;
755 free_extent_buffer(mid);
757 orig_slot -= btrfs_header_nritems(left);
758 path->slots[level] = orig_slot;
761 /* double check we haven't messed things up */
762 check_block(root, path, level);
764 btrfs_node_blockptr(path->nodes[level], path->slots[level]))
768 free_extent_buffer(right);
770 free_extent_buffer(left);
774 /* returns zero if the push worked, non-zero otherwise */
775 static int push_nodes_for_insert(struct btrfs_trans_handle *trans,
776 struct btrfs_root *root,
777 struct btrfs_path *path, int level)
779 struct extent_buffer *right = NULL;
780 struct extent_buffer *mid;
781 struct extent_buffer *left = NULL;
782 struct extent_buffer *parent = NULL;
786 int orig_slot = path->slots[level];
792 mid = path->nodes[level];
793 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
795 if (level < BTRFS_MAX_LEVEL - 1)
796 parent = path->nodes[level + 1];
797 pslot = path->slots[level + 1];
802 left = read_node_slot(root, parent, pslot - 1);
804 /* first, try to make some room in the middle buffer */
807 left_nr = btrfs_header_nritems(left);
808 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
811 ret = btrfs_cow_block(trans, root, left, parent,
816 wret = push_node_left(trans, root,
823 struct btrfs_disk_key disk_key;
824 orig_slot += left_nr;
825 btrfs_node_key(mid, &disk_key, 0);
826 btrfs_set_node_key(parent, &disk_key, pslot);
827 btrfs_mark_buffer_dirty(parent);
828 if (btrfs_header_nritems(left) > orig_slot) {
829 path->nodes[level] = left;
830 path->slots[level + 1] -= 1;
831 path->slots[level] = orig_slot;
832 free_extent_buffer(mid);
835 btrfs_header_nritems(left);
836 path->slots[level] = orig_slot;
837 free_extent_buffer(left);
841 free_extent_buffer(left);
843 right= read_node_slot(root, parent, pslot + 1);
846 * then try to empty the right most buffer into the middle
850 right_nr = btrfs_header_nritems(right);
851 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
854 ret = btrfs_cow_block(trans, root, right,
860 wret = balance_node_right(trans, root,
867 struct btrfs_disk_key disk_key;
869 btrfs_node_key(right, &disk_key, 0);
870 btrfs_set_node_key(parent, &disk_key, pslot + 1);
871 btrfs_mark_buffer_dirty(parent);
873 if (btrfs_header_nritems(mid) <= orig_slot) {
874 path->nodes[level] = right;
875 path->slots[level + 1] += 1;
876 path->slots[level] = orig_slot -
877 btrfs_header_nritems(mid);
878 free_extent_buffer(mid);
880 free_extent_buffer(right);
884 free_extent_buffer(right);
890 * readahead one full node of leaves
892 static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
897 struct extent_buffer *node;
905 int direction = path->reada;
907 struct radix_tree_root found;
908 unsigned long gang[8];
909 struct extent_buffer *eb;
915 if (!path->nodes[level])
918 node = path->nodes[level];
919 search = btrfs_node_blockptr(node, slot);
920 eb = btrfs_find_tree_block(root, search);
922 free_extent_buffer(eb);
926 init_bit_radix(&found);
927 nritems = btrfs_header_nritems(node);
928 level = btrfs_header_level(node) - 1;
929 for (i = slot; i < nritems; i++) {
930 bytenr = btrfs_node_blockptr(node, i);
931 set_radix_bit(&found, blocknr);
934 cluster_start = search - 4;
935 if (cluster_start > search)
938 cluster_start = search + 4;
940 ret = find_first_radix_bit(&found, gang, 0, ARRAY_SIZE(gang));
943 for (i = 0; i < ret; i++) {
945 clear_radix_bit(&found, blocknr);
946 if (path->reada == 1 && nread > 16)
948 if (close_blocks(cluster_start, blocknr)) {
949 readahead_tree_block(root, blocknr);
951 cluster_start = blocknr;
958 * look for key in the tree. path is filled in with nodes along the way
959 * if key is found, we return zero and you can find the item in the leaf
960 * level of the path (level 0)
962 * If the key isn't found, the path points to the slot where it should
963 * be inserted, and 1 is returned. If there are other errors during the
964 * search a negative error number is returned.
966 * if ins_len > 0, nodes and leaves will be split as we walk down the
967 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
970 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
971 *root, struct btrfs_key *key, struct btrfs_path *p, int
974 struct extent_buffer *b;
979 int should_reada = p->reada;
982 lowest_level = p->lowest_level;
983 WARN_ON(lowest_level && ins_len);
984 WARN_ON(p->nodes[0] != NULL);
985 WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
988 extent_buffer_get(b);
990 level = btrfs_header_level(b);
993 wret = btrfs_cow_block(trans, root, b,
998 free_extent_buffer(b);
1002 BUG_ON(!cow && ins_len);
1003 if (level != btrfs_header_level(b))
1005 level = btrfs_header_level(b);
1006 p->nodes[level] = b;
1007 ret = check_block(root, p, level);
1010 ret = bin_search(b, key, level, &slot);
1012 if (ret && slot > 0)
1014 p->slots[level] = slot;
1015 if (ins_len > 0 && btrfs_header_nritems(b) >=
1016 BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1017 int sret = split_node(trans, root, p, level);
1021 b = p->nodes[level];
1022 slot = p->slots[level];
1023 } else if (ins_len < 0) {
1024 int sret = balance_level(trans, root, p,
1028 b = p->nodes[level];
1030 btrfs_release_path(NULL, p);
1033 slot = p->slots[level];
1034 BUG_ON(btrfs_header_nritems(b) == 1);
1036 /* this is only true while dropping a snapshot */
1037 if (level == lowest_level)
1039 bytenr = btrfs_node_blockptr(b, slot);
1041 reada_for_search(root, p, level, slot);
1042 b = read_tree_block(root, bytenr,
1043 btrfs_level_size(root, level - 1));
1045 p->slots[level] = slot;
1046 if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
1047 sizeof(struct btrfs_item) + ins_len) {
1048 int sret = split_leaf(trans, root, key,
1061 * adjust the pointers going up the tree, starting at level
1062 * making sure the right key of each node is points to 'key'.
1063 * This is used after shifting pointers to the left, so it stops
1064 * fixing up pointers when a given leaf/node is not in slot 0 of the
1067 * If this fails to write a tree block, it returns -1, but continues
1068 * fixing up the blocks in ram so the tree is consistent.
1070 static int fixup_low_keys(struct btrfs_trans_handle *trans,
1071 struct btrfs_root *root, struct btrfs_path *path,
1072 struct btrfs_disk_key *key, int level)
1076 struct extent_buffer *t;
1078 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1079 int tslot = path->slots[i];
1080 if (!path->nodes[i])
1083 btrfs_set_node_key(t, key, tslot);
1084 btrfs_mark_buffer_dirty(path->nodes[i]);
1092 * try to push data from one node into the next node left in the
1095 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1096 * error, and > 0 if there was no room in the left hand block.
1098 static int push_node_left(struct btrfs_trans_handle *trans, struct btrfs_root
1099 *root, struct extent_buffer *dst,
1100 struct extent_buffer *src)
1107 src_nritems = btrfs_header_nritems(src);
1108 dst_nritems = btrfs_header_nritems(dst);
1109 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1111 if (push_items <= 0) {
1115 if (src_nritems < push_items)
1116 push_items = src_nritems;
1118 copy_extent_buffer(dst, src,
1119 btrfs_node_key_ptr_offset(dst_nritems),
1120 btrfs_node_key_ptr_offset(0),
1121 push_items * sizeof(struct btrfs_key_ptr));
1123 if (push_items < src_nritems) {
1124 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1125 btrfs_node_key_ptr_offset(push_items),
1126 (src_nritems - push_items) *
1127 sizeof(struct btrfs_key_ptr));
1129 btrfs_set_header_nritems(src, src_nritems - push_items);
1130 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1131 btrfs_mark_buffer_dirty(src);
1132 btrfs_mark_buffer_dirty(dst);
1137 * try to push data from one node into the next node right in the
1140 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1141 * error, and > 0 if there was no room in the right hand block.
1143 * this will only push up to 1/2 the contents of the left node over
1145 static int balance_node_right(struct btrfs_trans_handle *trans,
1146 struct btrfs_root *root,
1147 struct extent_buffer *dst,
1148 struct extent_buffer *src)
1156 src_nritems = btrfs_header_nritems(src);
1157 dst_nritems = btrfs_header_nritems(dst);
1158 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1159 if (push_items <= 0)
1162 max_push = src_nritems / 2 + 1;
1163 /* don't try to empty the node */
1164 if (max_push >= src_nritems)
1167 if (max_push < push_items)
1168 push_items = max_push;
1170 memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1171 btrfs_node_key_ptr_offset(0),
1173 sizeof(struct btrfs_key_ptr));
1175 copy_extent_buffer(dst, src,
1176 btrfs_node_key_ptr_offset(0),
1177 btrfs_node_key_ptr_offset(src_nritems - push_items),
1178 push_items * sizeof(struct btrfs_key_ptr));
1180 btrfs_set_header_nritems(src, src_nritems - push_items);
1181 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1183 btrfs_mark_buffer_dirty(src);
1184 btrfs_mark_buffer_dirty(dst);
1189 * helper function to insert a new root level in the tree.
1190 * A new node is allocated, and a single item is inserted to
1191 * point to the existing root
1193 * returns zero on success or < 0 on failure.
1195 static int insert_new_root(struct btrfs_trans_handle *trans,
1196 struct btrfs_root *root,
1197 struct btrfs_path *path, int level)
1199 struct extent_buffer *lower;
1200 struct extent_buffer *c;
1201 struct btrfs_disk_key lower_key;
1203 BUG_ON(path->nodes[level]);
1204 BUG_ON(path->nodes[level-1] != root->node);
1206 c = btrfs_alloc_free_block(trans, root, root->nodesize,
1207 root->node->start, 0);
1210 memset_extent_buffer(c, 0, 0, root->nodesize);
1211 btrfs_set_header_nritems(c, 1);
1212 btrfs_set_header_level(c, level);
1213 btrfs_set_header_bytenr(c, c->start);
1214 btrfs_set_header_generation(c, trans->transid);
1215 btrfs_set_header_owner(c, root->root_key.objectid);
1216 lower = path->nodes[level-1];
1218 write_extent_buffer(c, root->fs_info->fsid,
1219 (unsigned long)btrfs_header_fsid(c),
1222 btrfs_item_key(lower, &lower_key, 0);
1224 btrfs_node_key(lower, &lower_key, 0);
1225 btrfs_set_node_key(c, &lower_key, 0);
1226 btrfs_set_node_blockptr(c, 0, lower->start);
1228 btrfs_mark_buffer_dirty(c);
1230 /* the super has an extra ref to root->node */
1231 free_extent_buffer(root->node);
1233 extent_buffer_get(c);
1234 path->nodes[level] = c;
1235 path->slots[level] = 0;
1240 * worker function to insert a single pointer in a node.
1241 * the node should have enough room for the pointer already
1243 * slot and level indicate where you want the key to go, and
1244 * blocknr is the block the key points to.
1246 * returns zero on success and < 0 on any error
1248 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1249 *root, struct btrfs_path *path, struct btrfs_disk_key
1250 *key, u64 bytenr, int slot, int level)
1252 struct extent_buffer *lower;
1255 BUG_ON(!path->nodes[level]);
1256 lower = path->nodes[level];
1257 nritems = btrfs_header_nritems(lower);
1260 if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1262 if (slot != nritems) {
1263 memmove_extent_buffer(lower,
1264 btrfs_node_key_ptr_offset(slot + 1),
1265 btrfs_node_key_ptr_offset(slot),
1266 (nritems - slot) * sizeof(struct btrfs_key_ptr));
1268 btrfs_set_node_key(lower, key, slot);
1269 btrfs_set_node_blockptr(lower, slot, bytenr);
1270 btrfs_set_header_nritems(lower, nritems + 1);
1271 btrfs_mark_buffer_dirty(lower);
1276 * split the node at the specified level in path in two.
1277 * The path is corrected to point to the appropriate node after the split
1279 * Before splitting this tries to make some room in the node by pushing
1280 * left and right, if either one works, it returns right away.
1282 * returns 0 on success and < 0 on failure
1284 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1285 *root, struct btrfs_path *path, int level)
1287 struct extent_buffer *c;
1288 struct extent_buffer *split;
1289 struct btrfs_disk_key disk_key;
1295 c = path->nodes[level];
1296 if (c == root->node) {
1297 /* trying to split the root, lets make a new one */
1298 ret = insert_new_root(trans, root, path, level + 1);
1302 ret = push_nodes_for_insert(trans, root, path, level);
1303 c = path->nodes[level];
1304 if (!ret && btrfs_header_nritems(c) <
1305 BTRFS_NODEPTRS_PER_BLOCK(root) - 1)
1311 c_nritems = btrfs_header_nritems(c);
1312 split = btrfs_alloc_free_block(trans, root, root->nodesize,
1315 return PTR_ERR(split);
1317 btrfs_set_header_flags(split, btrfs_header_flags(c));
1318 btrfs_set_header_level(split, btrfs_header_level(c));
1319 btrfs_set_header_bytenr(split, split->start);
1320 btrfs_set_header_generation(split, trans->transid);
1321 btrfs_set_header_owner(split, root->root_key.objectid);
1322 write_extent_buffer(split, root->fs_info->fsid,
1323 (unsigned long)btrfs_header_fsid(split),
1326 mid = (c_nritems + 1) / 2;
1328 copy_extent_buffer(split, c,
1329 btrfs_node_key_ptr_offset(0),
1330 btrfs_node_key_ptr_offset(mid),
1331 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1332 btrfs_set_header_nritems(split, c_nritems - mid);
1333 btrfs_set_header_nritems(c, mid);
1336 btrfs_mark_buffer_dirty(c);
1337 btrfs_mark_buffer_dirty(split);
1339 btrfs_node_key(split, &disk_key, 0);
1340 wret = insert_ptr(trans, root, path, &disk_key, split->start,
1341 path->slots[level + 1] + 1,
1346 if (path->slots[level] >= mid) {
1347 path->slots[level] -= mid;
1348 free_extent_buffer(c);
1349 path->nodes[level] = split;
1350 path->slots[level + 1] += 1;
1352 free_extent_buffer(split);
1358 * how many bytes are required to store the items in a leaf. start
1359 * and nr indicate which items in the leaf to check. This totals up the
1360 * space used both by the item structs and the item data
1362 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1365 int nritems = btrfs_header_nritems(l);
1366 int end = min(nritems, start + nr) - 1;
1370 data_len = btrfs_item_end_nr(l, start);
1371 data_len = data_len - btrfs_item_offset_nr(l, end);
1372 data_len += sizeof(struct btrfs_item) * nr;
1373 WARN_ON(data_len < 0);
1378 * The space between the end of the leaf items and
1379 * the start of the leaf data. IOW, how much room
1380 * the leaf has left for both items and data
1382 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
1384 int nritems = btrfs_header_nritems(leaf);
1386 ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
1388 printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
1389 ret, BTRFS_LEAF_DATA_SIZE(root),
1390 leaf_space_used(leaf, 0, nritems), nritems);
1396 * push some data in the path leaf to the right, trying to free up at
1397 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1399 * returns 1 if the push failed because the other node didn't have enough
1400 * room, 0 if everything worked out and < 0 if there were major errors.
1402 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1403 *root, struct btrfs_path *path, int data_size)
1405 struct extent_buffer *left = path->nodes[0];
1406 struct extent_buffer *right;
1407 struct extent_buffer *upper;
1408 struct btrfs_disk_key disk_key;
1414 struct btrfs_item *item;
1421 slot = path->slots[1];
1422 if (!path->nodes[1]) {
1425 upper = path->nodes[1];
1426 if (slot >= btrfs_header_nritems(upper) - 1)
1429 right = read_tree_block(root, btrfs_node_blockptr(upper, slot + 1),
1431 free_space = btrfs_leaf_free_space(root, right);
1432 if (free_space < data_size + sizeof(struct btrfs_item)) {
1433 free_extent_buffer(right);
1437 /* cow and double check */
1438 ret = btrfs_cow_block(trans, root, right, upper,
1441 free_extent_buffer(right);
1444 free_space = btrfs_leaf_free_space(root, right);
1445 if (free_space < data_size + sizeof(struct btrfs_item)) {
1446 free_extent_buffer(right);
1450 left_nritems = btrfs_header_nritems(left);
1451 if (left_nritems == 0) {
1452 free_extent_buffer(right);
1456 for (i = left_nritems - 1; i >= 1; i--) {
1457 item = btrfs_item_nr(left, i);
1459 if (path->slots[0] == i)
1460 push_space += data_size + sizeof(*item);
1462 if (!left->map_token) {
1463 map_extent_buffer(left, (unsigned long)item,
1464 sizeof(struct btrfs_item),
1465 &left->map_token, &left->kaddr,
1466 &left->map_start, &left->map_len,
1470 this_item_size = btrfs_item_size(left, item);
1471 if (this_item_size + sizeof(*item) + push_space > free_space)
1474 push_space += this_item_size + sizeof(*item);
1476 if (left->map_token) {
1477 unmap_extent_buffer(left, left->map_token, KM_USER1);
1478 left->map_token = NULL;
1481 if (push_items == 0) {
1482 free_extent_buffer(right);
1486 if (push_items == left_nritems)
1489 /* push left to right */
1490 right_nritems = btrfs_header_nritems(right);
1491 push_space = btrfs_item_end_nr(left, left_nritems - push_items);
1492 push_space -= leaf_data_end(root, left);
1494 /* make room in the right data area */
1495 data_end = leaf_data_end(root, right);
1496 memmove_extent_buffer(right,
1497 btrfs_leaf_data(right) + data_end - push_space,
1498 btrfs_leaf_data(right) + data_end,
1499 BTRFS_LEAF_DATA_SIZE(root) - data_end);
1501 /* copy from the left data area */
1502 copy_extent_buffer(right, left, btrfs_leaf_data(right) +
1503 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1504 btrfs_leaf_data(left) + leaf_data_end(root, left),
1507 memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
1508 btrfs_item_nr_offset(0),
1509 right_nritems * sizeof(struct btrfs_item));
1511 /* copy the items from left to right */
1512 copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
1513 btrfs_item_nr_offset(left_nritems - push_items),
1514 push_items * sizeof(struct btrfs_item));
1516 /* update the item pointers */
1517 right_nritems += push_items;
1518 btrfs_set_header_nritems(right, right_nritems);
1519 push_space = BTRFS_LEAF_DATA_SIZE(root);
1521 for (i = 0; i < right_nritems; i++) {
1522 item = btrfs_item_nr(right, i);
1523 if (!right->map_token) {
1524 map_extent_buffer(right, (unsigned long)item,
1525 sizeof(struct btrfs_item),
1526 &right->map_token, &right->kaddr,
1527 &right->map_start, &right->map_len,
1530 push_space -= btrfs_item_size(right, item);
1531 btrfs_set_item_offset(right, item, push_space);
1534 if (right->map_token) {
1535 unmap_extent_buffer(right, right->map_token, KM_USER1);
1536 right->map_token = NULL;
1538 left_nritems -= push_items;
1539 btrfs_set_header_nritems(left, left_nritems);
1541 btrfs_mark_buffer_dirty(left);
1542 btrfs_mark_buffer_dirty(right);
1544 btrfs_item_key(right, &disk_key, 0);
1545 btrfs_set_node_key(upper, &disk_key, slot + 1);
1546 btrfs_mark_buffer_dirty(upper);
1548 /* then fixup the leaf pointer in the path */
1549 if (path->slots[0] >= left_nritems) {
1550 path->slots[0] -= left_nritems;
1551 free_extent_buffer(path->nodes[0]);
1552 path->nodes[0] = right;
1553 path->slots[1] += 1;
1555 free_extent_buffer(right);
1560 * push some data in the path leaf to the left, trying to free up at
1561 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1563 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1564 *root, struct btrfs_path *path, int data_size)
1566 struct btrfs_disk_key disk_key;
1567 struct extent_buffer *right = path->nodes[0];
1568 struct extent_buffer *left;
1574 struct btrfs_item *item;
1575 u32 old_left_nritems;
1580 u32 old_left_item_size;
1582 slot = path->slots[1];
1585 if (!path->nodes[1])
1588 left = read_tree_block(root, btrfs_node_blockptr(path->nodes[1],
1589 slot - 1), root->leafsize);
1590 free_space = btrfs_leaf_free_space(root, left);
1591 if (free_space < data_size + sizeof(struct btrfs_item)) {
1592 free_extent_buffer(left);
1596 /* cow and double check */
1597 ret = btrfs_cow_block(trans, root, left,
1598 path->nodes[1], slot - 1, &left);
1600 /* we hit -ENOSPC, but it isn't fatal here */
1601 free_extent_buffer(left);
1604 free_space = btrfs_leaf_free_space(root, left);
1605 if (free_space < data_size + sizeof(struct btrfs_item)) {
1606 free_extent_buffer(left);
1610 right_nritems = btrfs_header_nritems(right);
1611 if (right_nritems == 0) {
1612 free_extent_buffer(left);
1616 for (i = 0; i < right_nritems - 1; i++) {
1617 item = btrfs_item_nr(right, i);
1618 if (!right->map_token) {
1619 map_extent_buffer(right, (unsigned long)item,
1620 sizeof(struct btrfs_item),
1621 &right->map_token, &right->kaddr,
1622 &right->map_start, &right->map_len,
1626 if (path->slots[0] == i)
1627 push_space += data_size + sizeof(*item);
1629 this_item_size = btrfs_item_size(right, item);
1630 if (this_item_size + sizeof(*item) + push_space > free_space)
1634 push_space += this_item_size + sizeof(*item);
1637 if (right->map_token) {
1638 unmap_extent_buffer(right, right->map_token, KM_USER1);
1639 right->map_token = NULL;
1642 if (push_items == 0) {
1643 free_extent_buffer(left);
1646 if (push_items == btrfs_header_nritems(right))
1649 /* push data from right to left */
1650 copy_extent_buffer(left, right,
1651 btrfs_item_nr_offset(btrfs_header_nritems(left)),
1652 btrfs_item_nr_offset(0),
1653 push_items * sizeof(struct btrfs_item));
1655 push_space = BTRFS_LEAF_DATA_SIZE(root) -
1656 btrfs_item_offset_nr(right, push_items -1);
1658 copy_extent_buffer(left, right, btrfs_leaf_data(left) +
1659 leaf_data_end(root, left) - push_space,
1660 btrfs_leaf_data(right) +
1661 btrfs_item_offset_nr(right, push_items - 1),
1663 old_left_nritems = btrfs_header_nritems(left);
1664 BUG_ON(old_left_nritems < 0);
1666 old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
1667 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1670 item = btrfs_item_nr(left, i);
1671 if (!left->map_token) {
1672 map_extent_buffer(left, (unsigned long)item,
1673 sizeof(struct btrfs_item),
1674 &left->map_token, &left->kaddr,
1675 &left->map_start, &left->map_len,
1679 ioff = btrfs_item_offset(left, item);
1680 btrfs_set_item_offset(left, item,
1681 ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
1683 btrfs_set_header_nritems(left, old_left_nritems + push_items);
1684 if (left->map_token) {
1685 unmap_extent_buffer(left, left->map_token, KM_USER1);
1686 left->map_token = NULL;
1689 /* fixup right node */
1690 push_space = btrfs_item_offset_nr(right, push_items - 1) -
1691 leaf_data_end(root, right);
1692 memmove_extent_buffer(right, btrfs_leaf_data(right) +
1693 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1694 btrfs_leaf_data(right) +
1695 leaf_data_end(root, right), push_space);
1697 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
1698 btrfs_item_nr_offset(push_items),
1699 (btrfs_header_nritems(right) - push_items) *
1700 sizeof(struct btrfs_item));
1702 right_nritems = btrfs_header_nritems(right) - push_items;
1703 btrfs_set_header_nritems(right, right_nritems);
1704 push_space = BTRFS_LEAF_DATA_SIZE(root);
1706 for (i = 0; i < right_nritems; i++) {
1707 item = btrfs_item_nr(right, i);
1709 if (!right->map_token) {
1710 map_extent_buffer(right, (unsigned long)item,
1711 sizeof(struct btrfs_item),
1712 &right->map_token, &right->kaddr,
1713 &right->map_start, &right->map_len,
1717 push_space = push_space - btrfs_item_size(right, item);
1718 btrfs_set_item_offset(right, item, push_space);
1720 if (right->map_token) {
1721 unmap_extent_buffer(right, right->map_token, KM_USER1);
1722 right->map_token = NULL;
1725 btrfs_mark_buffer_dirty(left);
1726 btrfs_mark_buffer_dirty(right);
1728 btrfs_item_key(right, &disk_key, 0);
1729 wret = fixup_low_keys(trans, root, path, &disk_key, 1);
1733 /* then fixup the leaf pointer in the path */
1734 if (path->slots[0] < push_items) {
1735 path->slots[0] += old_left_nritems;
1736 free_extent_buffer(path->nodes[0]);
1737 path->nodes[0] = left;
1738 path->slots[1] -= 1;
1740 free_extent_buffer(left);
1741 path->slots[0] -= push_items;
1743 BUG_ON(path->slots[0] < 0);
1748 * split the path's leaf in two, making sure there is at least data_size
1749 * available for the resulting leaf level of the path.
1751 * returns 0 if all went well and < 0 on failure.
1753 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
1754 *root, struct btrfs_key *ins_key,
1755 struct btrfs_path *path, int data_size)
1757 struct extent_buffer *l;
1761 struct extent_buffer *right;
1762 int space_needed = data_size + sizeof(struct btrfs_item);
1768 int double_split = 0;
1769 struct btrfs_disk_key disk_key;
1771 /* first try to make some room by pushing left and right */
1772 wret = push_leaf_left(trans, root, path, data_size);
1776 wret = push_leaf_right(trans, root, path, data_size);
1782 /* did the pushes work? */
1783 if (btrfs_leaf_free_space(root, l) >=
1784 sizeof(struct btrfs_item) + data_size)
1787 if (!path->nodes[1]) {
1788 ret = insert_new_root(trans, root, path, 1);
1792 slot = path->slots[0];
1793 nritems = btrfs_header_nritems(l);
1794 mid = (nritems + 1)/ 2;
1796 right = btrfs_alloc_free_block(trans, root, root->leafsize,
1799 return PTR_ERR(right);
1801 memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
1802 btrfs_set_header_bytenr(right, right->start);
1803 btrfs_set_header_generation(right, trans->transid);
1804 btrfs_set_header_owner(right, root->root_key.objectid);
1805 btrfs_set_header_level(right, 0);
1806 write_extent_buffer(right, root->fs_info->fsid,
1807 (unsigned long)btrfs_header_fsid(right),
1812 leaf_space_used(l, mid, nritems - mid) + space_needed >
1813 BTRFS_LEAF_DATA_SIZE(root)) {
1814 if (slot >= nritems) {
1815 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1816 btrfs_set_header_nritems(right, 0);
1817 wret = insert_ptr(trans, root, path,
1818 &disk_key, right->start,
1819 path->slots[1] + 1, 1);
1822 free_extent_buffer(path->nodes[0]);
1823 path->nodes[0] = right;
1825 path->slots[1] += 1;
1832 if (leaf_space_used(l, 0, mid + 1) + space_needed >
1833 BTRFS_LEAF_DATA_SIZE(root)) {
1835 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1836 btrfs_set_header_nritems(right, 0);
1837 wret = insert_ptr(trans, root, path,
1843 free_extent_buffer(path->nodes[0]);
1844 path->nodes[0] = right;
1846 if (path->slots[1] == 0) {
1847 wret = fixup_low_keys(trans, root,
1848 path, &disk_key, 1);
1858 nritems = nritems - mid;
1859 btrfs_set_header_nritems(right, nritems);
1860 data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
1862 copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
1863 btrfs_item_nr_offset(mid),
1864 nritems * sizeof(struct btrfs_item));
1866 copy_extent_buffer(right, l,
1867 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
1868 data_copy_size, btrfs_leaf_data(l) +
1869 leaf_data_end(root, l), data_copy_size);
1871 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
1872 btrfs_item_end_nr(l, mid);
1874 for (i = 0; i < nritems; i++) {
1875 struct btrfs_item *item = btrfs_item_nr(right, i);
1878 if (!right->map_token) {
1879 map_extent_buffer(right, (unsigned long)item,
1880 sizeof(struct btrfs_item),
1881 &right->map_token, &right->kaddr,
1882 &right->map_start, &right->map_len,
1886 ioff = btrfs_item_offset(right, item);
1887 btrfs_set_item_offset(right, item, ioff + rt_data_off);
1890 if (right->map_token) {
1891 unmap_extent_buffer(right, right->map_token, KM_USER1);
1892 right->map_token = NULL;
1895 btrfs_set_header_nritems(l, mid);
1897 btrfs_item_key(right, &disk_key, 0);
1898 wret = insert_ptr(trans, root, path, &disk_key, right->start,
1899 path->slots[1] + 1, 1);
1903 btrfs_mark_buffer_dirty(right);
1904 btrfs_mark_buffer_dirty(l);
1905 BUG_ON(path->slots[0] != slot);
1908 free_extent_buffer(path->nodes[0]);
1909 path->nodes[0] = right;
1910 path->slots[0] -= mid;
1911 path->slots[1] += 1;
1913 free_extent_buffer(right);
1915 BUG_ON(path->slots[0] < 0);
1920 right = btrfs_alloc_free_block(trans, root, root->leafsize,
1923 return PTR_ERR(right);
1925 memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
1926 btrfs_set_header_bytenr(right, right->start);
1927 btrfs_set_header_generation(right, trans->transid);
1928 btrfs_set_header_owner(right, root->root_key.objectid);
1929 btrfs_set_header_level(right, 0);
1930 write_extent_buffer(right, root->fs_info->fsid,
1931 (unsigned long)btrfs_header_fsid(right),
1934 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1935 btrfs_set_header_nritems(right, 0);
1936 wret = insert_ptr(trans, root, path,
1937 &disk_key, right->start,
1941 if (path->slots[1] == 0) {
1942 wret = fixup_low_keys(trans, root, path, &disk_key, 1);
1946 free_extent_buffer(path->nodes[0]);
1947 path->nodes[0] = right;
1952 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
1953 struct btrfs_root *root,
1954 struct btrfs_path *path,
1960 struct extent_buffer *leaf;
1961 struct btrfs_item *item;
1963 unsigned int data_end;
1964 unsigned int old_data_start;
1965 unsigned int old_size;
1966 unsigned int size_diff;
1969 slot_orig = path->slots[0];
1970 leaf = path->nodes[0];
1972 nritems = btrfs_header_nritems(leaf);
1973 data_end = leaf_data_end(root, leaf);
1975 slot = path->slots[0];
1976 old_data_start = btrfs_item_offset_nr(leaf, slot);
1977 old_size = btrfs_item_size_nr(leaf, slot);
1978 BUG_ON(old_size <= new_size);
1979 size_diff = old_size - new_size;
1982 BUG_ON(slot >= nritems);
1985 * item0..itemN ... dataN.offset..dataN.size .. data0.size
1987 /* first correct the data pointers */
1988 for (i = slot; i < nritems; i++) {
1990 item = btrfs_item_nr(leaf, i);
1992 if (!leaf->map_token) {
1993 map_extent_buffer(leaf, (unsigned long)item,
1994 sizeof(struct btrfs_item),
1995 &leaf->map_token, &leaf->kaddr,
1996 &leaf->map_start, &leaf->map_len,
2000 ioff = btrfs_item_offset(leaf, item);
2001 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2004 if (leaf->map_token) {
2005 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2006 leaf->map_token = NULL;
2009 /* shift the data */
2010 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2011 data_end + size_diff, btrfs_leaf_data(leaf) +
2012 data_end, old_data_start + new_size - data_end);
2014 item = btrfs_item_nr(leaf, slot);
2015 btrfs_set_item_size(leaf, item, new_size);
2016 btrfs_mark_buffer_dirty(leaf);
2019 if (btrfs_leaf_free_space(root, leaf) < 0) {
2020 btrfs_print_leaf(root, leaf);
2026 int btrfs_extend_item(struct btrfs_trans_handle *trans,
2027 struct btrfs_root *root, struct btrfs_path *path,
2033 struct extent_buffer *leaf;
2034 struct btrfs_item *item;
2036 unsigned int data_end;
2037 unsigned int old_data;
2038 unsigned int old_size;
2041 slot_orig = path->slots[0];
2042 leaf = path->nodes[0];
2044 nritems = btrfs_header_nritems(leaf);
2045 data_end = leaf_data_end(root, leaf);
2047 if (btrfs_leaf_free_space(root, leaf) < data_size) {
2048 btrfs_print_leaf(root, leaf);
2051 slot = path->slots[0];
2052 old_data = btrfs_item_end_nr(leaf, slot);
2055 BUG_ON(slot >= nritems);
2058 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2060 /* first correct the data pointers */
2061 for (i = slot; i < nritems; i++) {
2063 item = btrfs_item_nr(leaf, i);
2065 if (!leaf->map_token) {
2066 map_extent_buffer(leaf, (unsigned long)item,
2067 sizeof(struct btrfs_item),
2068 &leaf->map_token, &leaf->kaddr,
2069 &leaf->map_start, &leaf->map_len,
2072 ioff = btrfs_item_offset(leaf, item);
2073 btrfs_set_item_offset(leaf, item, ioff - data_size);
2076 if (leaf->map_token) {
2077 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2078 leaf->map_token = NULL;
2081 /* shift the data */
2082 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2083 data_end - data_size, btrfs_leaf_data(leaf) +
2084 data_end, old_data - data_end);
2086 data_end = old_data;
2087 old_size = btrfs_item_size_nr(leaf, slot);
2088 item = btrfs_item_nr(leaf, slot);
2089 btrfs_set_item_size(leaf, item, old_size + data_size);
2090 btrfs_mark_buffer_dirty(leaf);
2093 if (btrfs_leaf_free_space(root, leaf) < 0) {
2094 btrfs_print_leaf(root, leaf);
2101 * Given a key and some data, insert an item into the tree.
2102 * This does all the path init required, making room in the tree if needed.
2104 int btrfs_insert_empty_item(struct btrfs_trans_handle *trans,
2105 struct btrfs_root *root,
2106 struct btrfs_path *path,
2107 struct btrfs_key *cpu_key, u32 data_size)
2109 struct extent_buffer *leaf;
2110 struct btrfs_item *item;
2115 unsigned int data_end;
2116 struct btrfs_disk_key disk_key;
2118 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2120 /* create a root if there isn't one */
2124 ret = btrfs_search_slot(trans, root, cpu_key, path, data_size, 1);
2131 slot_orig = path->slots[0];
2132 leaf = path->nodes[0];
2134 nritems = btrfs_header_nritems(leaf);
2135 data_end = leaf_data_end(root, leaf);
2137 if (btrfs_leaf_free_space(root, leaf) <
2138 sizeof(struct btrfs_item) + data_size) {
2142 slot = path->slots[0];
2145 if (slot != nritems) {
2147 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2149 if (old_data < data_end) {
2150 btrfs_print_leaf(root, leaf);
2151 printk("slot %d old_data %d data_end %d\n",
2152 slot, old_data, data_end);
2156 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2158 /* first correct the data pointers */
2159 WARN_ON(leaf->map_token);
2160 for (i = slot; i < nritems; i++) {
2163 item = btrfs_item_nr(leaf, i);
2164 if (!leaf->map_token) {
2165 map_extent_buffer(leaf, (unsigned long)item,
2166 sizeof(struct btrfs_item),
2167 &leaf->map_token, &leaf->kaddr,
2168 &leaf->map_start, &leaf->map_len,
2172 ioff = btrfs_item_offset(leaf, item);
2173 btrfs_set_item_offset(leaf, item, ioff - data_size);
2175 if (leaf->map_token) {
2176 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2177 leaf->map_token = NULL;
2180 /* shift the items */
2181 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1),
2182 btrfs_item_nr_offset(slot),
2183 (nritems - slot) * sizeof(struct btrfs_item));
2185 /* shift the data */
2186 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2187 data_end - data_size, btrfs_leaf_data(leaf) +
2188 data_end, old_data - data_end);
2189 data_end = old_data;
2192 /* setup the item for the new data */
2193 btrfs_set_item_key(leaf, &disk_key, slot);
2194 item = btrfs_item_nr(leaf, slot);
2195 btrfs_set_item_offset(leaf, item, data_end - data_size);
2196 btrfs_set_item_size(leaf, item, data_size);
2197 btrfs_set_header_nritems(leaf, nritems + 1);
2198 btrfs_mark_buffer_dirty(leaf);
2202 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
2204 if (btrfs_leaf_free_space(root, leaf) < 0) {
2205 btrfs_print_leaf(root, leaf);
2213 * Given a key and some data, insert an item into the tree.
2214 * This does all the path init required, making room in the tree if needed.
2216 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2217 *root, struct btrfs_key *cpu_key, void *data, u32
2221 struct btrfs_path *path;
2222 struct extent_buffer *leaf;
2225 path = btrfs_alloc_path();
2227 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2229 leaf = path->nodes[0];
2230 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2231 write_extent_buffer(leaf, data, ptr, data_size);
2232 btrfs_mark_buffer_dirty(leaf);
2234 btrfs_free_path(path);
2239 * delete the pointer from a given node.
2241 * If the delete empties a node, the node is removed from the tree,
2242 * continuing all the way the root if required. The root is converted into
2243 * a leaf if all the nodes are emptied.
2245 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2246 struct btrfs_path *path, int level, int slot)
2248 struct extent_buffer *parent = path->nodes[level];
2253 nritems = btrfs_header_nritems(parent);
2254 if (slot != nritems -1) {
2255 memmove_extent_buffer(parent,
2256 btrfs_node_key_ptr_offset(slot),
2257 btrfs_node_key_ptr_offset(slot + 1),
2258 sizeof(struct btrfs_key_ptr) *
2259 (nritems - slot - 1));
2262 btrfs_set_header_nritems(parent, nritems);
2263 if (nritems == 0 && parent == root->node) {
2264 BUG_ON(btrfs_header_level(root->node) != 1);
2265 /* just turn the root into a leaf and break */
2266 btrfs_set_header_level(root->node, 0);
2267 } else if (slot == 0) {
2268 struct btrfs_disk_key disk_key;
2270 btrfs_node_key(parent, &disk_key, 0);
2271 wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
2275 btrfs_mark_buffer_dirty(parent);
2280 * delete the item at the leaf level in path. If that empties
2281 * the leaf, remove it from the tree
2283 int btrfs_del_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2284 struct btrfs_path *path)
2287 struct extent_buffer *leaf;
2288 struct btrfs_item *item;
2295 leaf = path->nodes[0];
2296 slot = path->slots[0];
2297 doff = btrfs_item_offset_nr(leaf, slot);
2298 dsize = btrfs_item_size_nr(leaf, slot);
2299 nritems = btrfs_header_nritems(leaf);
2301 if (slot != nritems - 1) {
2303 int data_end = leaf_data_end(root, leaf);
2305 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2307 btrfs_leaf_data(leaf) + data_end,
2310 for (i = slot + 1; i < nritems; i++) {
2313 item = btrfs_item_nr(leaf, i);
2314 if (!leaf->map_token) {
2315 map_extent_buffer(leaf, (unsigned long)item,
2316 sizeof(struct btrfs_item),
2317 &leaf->map_token, &leaf->kaddr,
2318 &leaf->map_start, &leaf->map_len,
2321 ioff = btrfs_item_offset(leaf, item);
2322 btrfs_set_item_offset(leaf, item, ioff + dsize);
2325 if (leaf->map_token) {
2326 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2327 leaf->map_token = NULL;
2330 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2331 btrfs_item_nr_offset(slot + 1),
2332 sizeof(struct btrfs_item) *
2333 (nritems - slot - 1));
2335 btrfs_set_header_nritems(leaf, nritems - 1);
2338 /* delete the leaf if we've emptied it */
2340 if (leaf == root->node) {
2341 btrfs_set_header_level(leaf, 0);
2343 clean_tree_block(trans, root, leaf);
2344 wait_on_tree_block_writeback(root, leaf);
2345 wret = del_ptr(trans, root, path, 1, path->slots[1]);
2348 wret = btrfs_free_extent(trans, root,
2349 leaf->start, leaf->len, 1);
2354 int used = leaf_space_used(leaf, 0, nritems);
2356 struct btrfs_disk_key disk_key;
2358 btrfs_item_key(leaf, &disk_key, 0);
2359 wret = fixup_low_keys(trans, root, path,
2365 /* delete the leaf if it is mostly empty */
2366 if (used < BTRFS_LEAF_DATA_SIZE(root) / 3) {
2367 /* push_leaf_left fixes the path.
2368 * make sure the path still points to our leaf
2369 * for possible call to del_ptr below
2371 slot = path->slots[1];
2372 extent_buffer_get(leaf);
2374 wret = push_leaf_left(trans, root, path, 1);
2375 if (wret < 0 && wret != -ENOSPC)
2378 if (path->nodes[0] == leaf &&
2379 btrfs_header_nritems(leaf)) {
2380 wret = push_leaf_right(trans, root, path, 1);
2381 if (wret < 0 && wret != -ENOSPC)
2385 if (btrfs_header_nritems(leaf) == 0) {
2386 u64 bytenr = leaf->start;
2387 u32 blocksize = leaf->len;
2389 clean_tree_block(trans, root, leaf);
2390 wait_on_tree_block_writeback(root, leaf);
2392 wret = del_ptr(trans, root, path, 1, slot);
2396 free_extent_buffer(leaf);
2397 wret = btrfs_free_extent(trans, root, bytenr,
2402 btrfs_mark_buffer_dirty(leaf);
2403 free_extent_buffer(leaf);
2406 btrfs_mark_buffer_dirty(leaf);
2413 * walk up the tree as far as required to find the next leaf.
2414 * returns 0 if it found something or 1 if there are no greater leaves.
2415 * returns < 0 on io errors.
2417 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
2422 struct extent_buffer *c;
2423 struct extent_buffer *next = NULL;
2425 while(level < BTRFS_MAX_LEVEL) {
2426 if (!path->nodes[level])
2429 slot = path->slots[level] + 1;
2430 c = path->nodes[level];
2431 if (slot >= btrfs_header_nritems(c)) {
2436 bytenr = btrfs_node_blockptr(c, slot);
2438 free_extent_buffer(next);
2441 reada_for_search(root, path, level, slot);
2443 next = read_tree_block(root, bytenr,
2444 btrfs_level_size(root, level -1));
2447 path->slots[level] = slot;
2450 c = path->nodes[level];
2451 free_extent_buffer(c);
2452 path->nodes[level] = next;
2453 path->slots[level] = 0;
2457 reada_for_search(root, path, level, 0);
2458 next = read_tree_block(root, btrfs_node_blockptr(next, 0),
2459 btrfs_level_size(root, level - 1));