2 * Copyright (C) 2007,2008 Oracle. All rights reserved.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
19 #include <linux/sched.h>
20 #include <linux/slab.h>
21 #include <linux/rbtree.h>
24 #include "transaction.h"
25 #include "print-tree.h"
28 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
29 *root, struct btrfs_path *path, int level);
30 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
31 *root, struct btrfs_key *ins_key,
32 struct btrfs_path *path, int data_size, int extend);
33 static int push_node_left(struct btrfs_trans_handle *trans,
34 struct btrfs_root *root, struct extent_buffer *dst,
35 struct extent_buffer *src, int empty);
36 static int balance_node_right(struct btrfs_trans_handle *trans,
37 struct btrfs_root *root,
38 struct extent_buffer *dst_buf,
39 struct extent_buffer *src_buf);
40 static void del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
41 struct btrfs_path *path, int level, int slot,
43 static void tree_mod_log_free_eb(struct btrfs_fs_info *fs_info,
44 struct extent_buffer *eb);
45 struct extent_buffer *read_old_tree_block(struct btrfs_root *root, u64 bytenr,
46 u32 blocksize, u64 parent_transid,
48 struct extent_buffer *btrfs_find_old_tree_block(struct btrfs_root *root,
49 u64 bytenr, u32 blocksize,
52 struct btrfs_path *btrfs_alloc_path(void)
54 struct btrfs_path *path;
55 path = kmem_cache_zalloc(btrfs_path_cachep, GFP_NOFS);
60 * set all locked nodes in the path to blocking locks. This should
61 * be done before scheduling
63 noinline void btrfs_set_path_blocking(struct btrfs_path *p)
66 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
67 if (!p->nodes[i] || !p->locks[i])
69 btrfs_set_lock_blocking_rw(p->nodes[i], p->locks[i]);
70 if (p->locks[i] == BTRFS_READ_LOCK)
71 p->locks[i] = BTRFS_READ_LOCK_BLOCKING;
72 else if (p->locks[i] == BTRFS_WRITE_LOCK)
73 p->locks[i] = BTRFS_WRITE_LOCK_BLOCKING;
78 * reset all the locked nodes in the patch to spinning locks.
80 * held is used to keep lockdep happy, when lockdep is enabled
81 * we set held to a blocking lock before we go around and
82 * retake all the spinlocks in the path. You can safely use NULL
85 noinline void btrfs_clear_path_blocking(struct btrfs_path *p,
86 struct extent_buffer *held, int held_rw)
90 #ifdef CONFIG_DEBUG_LOCK_ALLOC
91 /* lockdep really cares that we take all of these spinlocks
92 * in the right order. If any of the locks in the path are not
93 * currently blocking, it is going to complain. So, make really
94 * really sure by forcing the path to blocking before we clear
98 btrfs_set_lock_blocking_rw(held, held_rw);
99 if (held_rw == BTRFS_WRITE_LOCK)
100 held_rw = BTRFS_WRITE_LOCK_BLOCKING;
101 else if (held_rw == BTRFS_READ_LOCK)
102 held_rw = BTRFS_READ_LOCK_BLOCKING;
104 btrfs_set_path_blocking(p);
107 for (i = BTRFS_MAX_LEVEL - 1; i >= 0; i--) {
108 if (p->nodes[i] && p->locks[i]) {
109 btrfs_clear_lock_blocking_rw(p->nodes[i], p->locks[i]);
110 if (p->locks[i] == BTRFS_WRITE_LOCK_BLOCKING)
111 p->locks[i] = BTRFS_WRITE_LOCK;
112 else if (p->locks[i] == BTRFS_READ_LOCK_BLOCKING)
113 p->locks[i] = BTRFS_READ_LOCK;
117 #ifdef CONFIG_DEBUG_LOCK_ALLOC
119 btrfs_clear_lock_blocking_rw(held, held_rw);
123 /* this also releases the path */
124 void btrfs_free_path(struct btrfs_path *p)
128 btrfs_release_path(p);
129 kmem_cache_free(btrfs_path_cachep, p);
133 * path release drops references on the extent buffers in the path
134 * and it drops any locks held by this path
136 * It is safe to call this on paths that no locks or extent buffers held.
138 noinline void btrfs_release_path(struct btrfs_path *p)
142 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
147 btrfs_tree_unlock_rw(p->nodes[i], p->locks[i]);
150 free_extent_buffer(p->nodes[i]);
156 * safely gets a reference on the root node of a tree. A lock
157 * is not taken, so a concurrent writer may put a different node
158 * at the root of the tree. See btrfs_lock_root_node for the
161 * The extent buffer returned by this has a reference taken, so
162 * it won't disappear. It may stop being the root of the tree
163 * at any time because there are no locks held.
165 struct extent_buffer *btrfs_root_node(struct btrfs_root *root)
167 struct extent_buffer *eb;
171 eb = rcu_dereference(root->node);
174 * RCU really hurts here, we could free up the root node because
175 * it was cow'ed but we may not get the new root node yet so do
176 * the inc_not_zero dance and if it doesn't work then
177 * synchronize_rcu and try again.
179 if (atomic_inc_not_zero(&eb->refs)) {
189 /* loop around taking references on and locking the root node of the
190 * tree until you end up with a lock on the root. A locked buffer
191 * is returned, with a reference held.
193 struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root)
195 struct extent_buffer *eb;
198 eb = btrfs_root_node(root);
200 if (eb == root->node)
202 btrfs_tree_unlock(eb);
203 free_extent_buffer(eb);
208 /* loop around taking references on and locking the root node of the
209 * tree until you end up with a lock on the root. A locked buffer
210 * is returned, with a reference held.
212 struct extent_buffer *btrfs_read_lock_root_node(struct btrfs_root *root)
214 struct extent_buffer *eb;
217 eb = btrfs_root_node(root);
218 btrfs_tree_read_lock(eb);
219 if (eb == root->node)
221 btrfs_tree_read_unlock(eb);
222 free_extent_buffer(eb);
227 /* cowonly root (everything not a reference counted cow subvolume), just get
228 * put onto a simple dirty list. transaction.c walks this to make sure they
229 * get properly updated on disk.
231 static void add_root_to_dirty_list(struct btrfs_root *root)
233 spin_lock(&root->fs_info->trans_lock);
234 if (root->track_dirty && list_empty(&root->dirty_list)) {
235 list_add(&root->dirty_list,
236 &root->fs_info->dirty_cowonly_roots);
238 spin_unlock(&root->fs_info->trans_lock);
242 * used by snapshot creation to make a copy of a root for a tree with
243 * a given objectid. The buffer with the new root node is returned in
244 * cow_ret, and this func returns zero on success or a negative error code.
246 int btrfs_copy_root(struct btrfs_trans_handle *trans,
247 struct btrfs_root *root,
248 struct extent_buffer *buf,
249 struct extent_buffer **cow_ret, u64 new_root_objectid)
251 struct extent_buffer *cow;
254 struct btrfs_disk_key disk_key;
256 WARN_ON(root->ref_cows && trans->transid !=
257 root->fs_info->running_transaction->transid);
258 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
260 level = btrfs_header_level(buf);
262 btrfs_item_key(buf, &disk_key, 0);
264 btrfs_node_key(buf, &disk_key, 0);
266 cow = btrfs_alloc_free_block(trans, root, buf->len, 0,
267 new_root_objectid, &disk_key, level,
272 copy_extent_buffer(cow, buf, 0, 0, cow->len);
273 btrfs_set_header_bytenr(cow, cow->start);
274 btrfs_set_header_generation(cow, trans->transid);
275 btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV);
276 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN |
277 BTRFS_HEADER_FLAG_RELOC);
278 if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID)
279 btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC);
281 btrfs_set_header_owner(cow, new_root_objectid);
283 write_extent_buffer(cow, root->fs_info->fsid,
284 (unsigned long)btrfs_header_fsid(cow),
287 WARN_ON(btrfs_header_generation(buf) > trans->transid);
288 if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID)
289 ret = btrfs_inc_ref(trans, root, cow, 1, 1);
291 ret = btrfs_inc_ref(trans, root, cow, 0, 1);
296 btrfs_mark_buffer_dirty(cow);
305 MOD_LOG_KEY_REMOVE_WHILE_FREEING,
306 MOD_LOG_KEY_REMOVE_WHILE_MOVING,
308 MOD_LOG_ROOT_REPLACE,
311 struct tree_mod_move {
316 struct tree_mod_root {
321 struct tree_mod_elem {
323 u64 index; /* shifted logical */
324 struct seq_list elem;
327 /* this is used for MOD_LOG_KEY_* and MOD_LOG_MOVE_KEYS operations */
330 /* this is used for MOD_LOG_KEY* and MOD_LOG_ROOT_REPLACE */
333 /* those are used for op == MOD_LOG_KEY_{REPLACE,REMOVE} */
334 struct btrfs_disk_key key;
337 /* this is used for op == MOD_LOG_MOVE_KEYS */
338 struct tree_mod_move move;
340 /* this is used for op == MOD_LOG_ROOT_REPLACE */
341 struct tree_mod_root old_root;
345 __get_tree_mod_seq(struct btrfs_fs_info *fs_info, struct seq_list *elem)
347 elem->seq = atomic_inc_return(&fs_info->tree_mod_seq);
348 list_add_tail(&elem->list, &fs_info->tree_mod_seq_list);
351 void btrfs_get_tree_mod_seq(struct btrfs_fs_info *fs_info,
352 struct seq_list *elem)
355 spin_lock(&fs_info->tree_mod_seq_lock);
356 __get_tree_mod_seq(fs_info, elem);
357 spin_unlock(&fs_info->tree_mod_seq_lock);
360 void btrfs_put_tree_mod_seq(struct btrfs_fs_info *fs_info,
361 struct seq_list *elem)
363 struct rb_root *tm_root;
364 struct rb_node *node;
365 struct rb_node *next;
366 struct seq_list *cur_elem;
367 struct tree_mod_elem *tm;
368 u64 min_seq = (u64)-1;
369 u64 seq_putting = elem->seq;
374 BUG_ON(!(elem->flags & 1));
375 spin_lock(&fs_info->tree_mod_seq_lock);
376 list_del(&elem->list);
378 list_for_each_entry(cur_elem, &fs_info->tree_mod_seq_list, list) {
379 if ((cur_elem->flags & 1) && cur_elem->seq < min_seq) {
380 if (seq_putting > cur_elem->seq) {
382 * blocker with lower sequence number exists, we
383 * cannot remove anything from the log
387 min_seq = cur_elem->seq;
392 * anything that's lower than the lowest existing (read: blocked)
393 * sequence number can be removed from the tree.
395 write_lock(&fs_info->tree_mod_log_lock);
396 tm_root = &fs_info->tree_mod_log;
397 for (node = rb_first(tm_root); node; node = next) {
398 next = rb_next(node);
399 tm = container_of(node, struct tree_mod_elem, node);
400 if (tm->elem.seq > min_seq)
402 rb_erase(node, tm_root);
403 list_del(&tm->elem.list);
406 write_unlock(&fs_info->tree_mod_log_lock);
408 spin_unlock(&fs_info->tree_mod_seq_lock);
412 * key order of the log:
415 * the index is the shifted logical of the *new* root node for root replace
416 * operations, or the shifted logical of the affected block for all other
420 __tree_mod_log_insert(struct btrfs_fs_info *fs_info, struct tree_mod_elem *tm)
422 struct rb_root *tm_root;
423 struct rb_node **new;
424 struct rb_node *parent = NULL;
425 struct tree_mod_elem *cur;
428 BUG_ON(!tm || !tm->elem.seq);
430 write_lock(&fs_info->tree_mod_log_lock);
431 tm_root = &fs_info->tree_mod_log;
432 new = &tm_root->rb_node;
434 cur = container_of(*new, struct tree_mod_elem, node);
436 if (cur->index < tm->index)
437 new = &((*new)->rb_left);
438 else if (cur->index > tm->index)
439 new = &((*new)->rb_right);
440 else if (cur->elem.seq < tm->elem.seq)
441 new = &((*new)->rb_left);
442 else if (cur->elem.seq > tm->elem.seq)
443 new = &((*new)->rb_right);
451 rb_link_node(&tm->node, parent, new);
452 rb_insert_color(&tm->node, tm_root);
454 write_unlock(&fs_info->tree_mod_log_lock);
458 static inline int tree_mod_dont_log(struct btrfs_fs_info *fs_info,
459 struct extent_buffer *eb) {
461 if (list_empty(&(fs_info)->tree_mod_seq_list))
465 if (btrfs_header_level(eb) == 0)
470 static inline int tree_mod_alloc(struct btrfs_fs_info *fs_info, gfp_t flags,
471 struct tree_mod_elem **tm_ret)
473 struct tree_mod_elem *tm;
476 if (tree_mod_dont_log(fs_info, NULL))
479 tm = *tm_ret = kzalloc(sizeof(*tm), flags);
484 spin_lock(&fs_info->tree_mod_seq_lock);
485 if (list_empty(&fs_info->tree_mod_seq_list)) {
487 * someone emptied the list while we were waiting for the lock.
488 * we must not add to the list, because no blocker exists. items
489 * are removed from the list only when the existing blocker is
490 * removed from the list.
495 __get_tree_mod_seq(fs_info, &tm->elem);
498 spin_unlock(&fs_info->tree_mod_seq_lock);
504 tree_mod_log_insert_key_mask(struct btrfs_fs_info *fs_info,
505 struct extent_buffer *eb, int slot,
506 enum mod_log_op op, gfp_t flags)
508 struct tree_mod_elem *tm;
511 ret = tree_mod_alloc(fs_info, flags, &tm);
515 tm->index = eb->start >> PAGE_CACHE_SHIFT;
516 if (op != MOD_LOG_KEY_ADD) {
517 btrfs_node_key(eb, &tm->key, slot);
518 tm->blockptr = btrfs_node_blockptr(eb, slot);
522 tm->generation = btrfs_node_ptr_generation(eb, slot);
524 return __tree_mod_log_insert(fs_info, tm);
528 tree_mod_log_insert_key(struct btrfs_fs_info *fs_info, struct extent_buffer *eb,
529 int slot, enum mod_log_op op)
531 return tree_mod_log_insert_key_mask(fs_info, eb, slot, op, GFP_NOFS);
535 tree_mod_log_insert_move(struct btrfs_fs_info *fs_info,
536 struct extent_buffer *eb, int dst_slot, int src_slot,
537 int nr_items, gfp_t flags)
539 struct tree_mod_elem *tm;
543 if (tree_mod_dont_log(fs_info, eb))
546 for (i = 0; i + dst_slot < src_slot && i < nr_items; i++) {
547 ret = tree_mod_log_insert_key(fs_info, eb, i + dst_slot,
548 MOD_LOG_KEY_REMOVE_WHILE_MOVING);
552 ret = tree_mod_alloc(fs_info, flags, &tm);
556 tm->index = eb->start >> PAGE_CACHE_SHIFT;
558 tm->move.dst_slot = dst_slot;
559 tm->move.nr_items = nr_items;
560 tm->op = MOD_LOG_MOVE_KEYS;
562 return __tree_mod_log_insert(fs_info, tm);
566 tree_mod_log_insert_root(struct btrfs_fs_info *fs_info,
567 struct extent_buffer *old_root,
568 struct extent_buffer *new_root, gfp_t flags)
570 struct tree_mod_elem *tm;
573 ret = tree_mod_alloc(fs_info, flags, &tm);
577 tm->index = new_root->start >> PAGE_CACHE_SHIFT;
578 tm->old_root.logical = old_root->start;
579 tm->old_root.level = btrfs_header_level(old_root);
580 tm->generation = btrfs_header_generation(old_root);
581 tm->op = MOD_LOG_ROOT_REPLACE;
583 return __tree_mod_log_insert(fs_info, tm);
586 static struct tree_mod_elem *
587 __tree_mod_log_search(struct btrfs_fs_info *fs_info, u64 start, u64 min_seq,
590 struct rb_root *tm_root;
591 struct rb_node *node;
592 struct tree_mod_elem *cur = NULL;
593 struct tree_mod_elem *found = NULL;
594 u64 index = start >> PAGE_CACHE_SHIFT;
596 read_lock(&fs_info->tree_mod_log_lock);
597 tm_root = &fs_info->tree_mod_log;
598 node = tm_root->rb_node;
600 cur = container_of(node, struct tree_mod_elem, node);
601 if (cur->index < index) {
602 node = node->rb_left;
603 } else if (cur->index > index) {
604 node = node->rb_right;
605 } else if (cur->elem.seq < min_seq) {
606 node = node->rb_left;
607 } else if (!smallest) {
608 /* we want the node with the highest seq */
610 BUG_ON(found->elem.seq > cur->elem.seq);
612 node = node->rb_left;
613 } else if (cur->elem.seq > min_seq) {
614 /* we want the node with the smallest seq */
616 BUG_ON(found->elem.seq < cur->elem.seq);
618 node = node->rb_right;
624 read_unlock(&fs_info->tree_mod_log_lock);
630 * this returns the element from the log with the smallest time sequence
631 * value that's in the log (the oldest log item). any element with a time
632 * sequence lower than min_seq will be ignored.
634 static struct tree_mod_elem *
635 tree_mod_log_search_oldest(struct btrfs_fs_info *fs_info, u64 start,
638 return __tree_mod_log_search(fs_info, start, min_seq, 1);
642 * this returns the element from the log with the largest time sequence
643 * value that's in the log (the most recent log item). any element with
644 * a time sequence lower than min_seq will be ignored.
646 static struct tree_mod_elem *
647 tree_mod_log_search(struct btrfs_fs_info *fs_info, u64 start, u64 min_seq)
649 return __tree_mod_log_search(fs_info, start, min_seq, 0);
653 tree_mod_log_eb_copy(struct btrfs_fs_info *fs_info, struct extent_buffer *dst,
654 struct extent_buffer *src, unsigned long dst_offset,
655 unsigned long src_offset, int nr_items)
660 if (tree_mod_dont_log(fs_info, NULL))
663 if (btrfs_header_level(dst) == 0 && btrfs_header_level(src) == 0)
666 /* speed this up by single seq for all operations? */
667 for (i = 0; i < nr_items; i++) {
668 ret = tree_mod_log_insert_key(fs_info, src, i + src_offset,
671 ret = tree_mod_log_insert_key(fs_info, dst, i + dst_offset,
678 tree_mod_log_eb_move(struct btrfs_fs_info *fs_info, struct extent_buffer *dst,
679 int dst_offset, int src_offset, int nr_items)
682 ret = tree_mod_log_insert_move(fs_info, dst, dst_offset, src_offset,
688 tree_mod_log_set_node_key(struct btrfs_fs_info *fs_info,
689 struct extent_buffer *eb,
690 struct btrfs_disk_key *disk_key, int slot, int atomic)
694 ret = tree_mod_log_insert_key_mask(fs_info, eb, slot,
696 atomic ? GFP_ATOMIC : GFP_NOFS);
700 static void tree_mod_log_free_eb(struct btrfs_fs_info *fs_info,
701 struct extent_buffer *eb)
707 if (tree_mod_dont_log(fs_info, eb))
710 nritems = btrfs_header_nritems(eb);
711 for (i = nritems - 1; i >= 0; i--) {
712 ret = tree_mod_log_insert_key(fs_info, eb, i,
713 MOD_LOG_KEY_REMOVE_WHILE_FREEING);
719 tree_mod_log_set_root_pointer(struct btrfs_root *root,
720 struct extent_buffer *new_root_node)
723 tree_mod_log_free_eb(root->fs_info, root->node);
724 ret = tree_mod_log_insert_root(root->fs_info, root->node,
725 new_root_node, GFP_NOFS);
730 * check if the tree block can be shared by multiple trees
732 int btrfs_block_can_be_shared(struct btrfs_root *root,
733 struct extent_buffer *buf)
736 * Tree blocks not in refernece counted trees and tree roots
737 * are never shared. If a block was allocated after the last
738 * snapshot and the block was not allocated by tree relocation,
739 * we know the block is not shared.
741 if (root->ref_cows &&
742 buf != root->node && buf != root->commit_root &&
743 (btrfs_header_generation(buf) <=
744 btrfs_root_last_snapshot(&root->root_item) ||
745 btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)))
747 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
748 if (root->ref_cows &&
749 btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
755 static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans,
756 struct btrfs_root *root,
757 struct extent_buffer *buf,
758 struct extent_buffer *cow,
768 * Backrefs update rules:
770 * Always use full backrefs for extent pointers in tree block
771 * allocated by tree relocation.
773 * If a shared tree block is no longer referenced by its owner
774 * tree (btrfs_header_owner(buf) == root->root_key.objectid),
775 * use full backrefs for extent pointers in tree block.
777 * If a tree block is been relocating
778 * (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID),
779 * use full backrefs for extent pointers in tree block.
780 * The reason for this is some operations (such as drop tree)
781 * are only allowed for blocks use full backrefs.
784 if (btrfs_block_can_be_shared(root, buf)) {
785 ret = btrfs_lookup_extent_info(trans, root, buf->start,
786 buf->len, &refs, &flags);
791 btrfs_std_error(root->fs_info, ret);
796 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
797 btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
798 flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
803 owner = btrfs_header_owner(buf);
804 BUG_ON(owner == BTRFS_TREE_RELOC_OBJECTID &&
805 !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
808 if ((owner == root->root_key.objectid ||
809 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) &&
810 !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) {
811 ret = btrfs_inc_ref(trans, root, buf, 1, 1);
812 BUG_ON(ret); /* -ENOMEM */
814 if (root->root_key.objectid ==
815 BTRFS_TREE_RELOC_OBJECTID) {
816 ret = btrfs_dec_ref(trans, root, buf, 0, 1);
817 BUG_ON(ret); /* -ENOMEM */
818 ret = btrfs_inc_ref(trans, root, cow, 1, 1);
819 BUG_ON(ret); /* -ENOMEM */
821 new_flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
824 if (root->root_key.objectid ==
825 BTRFS_TREE_RELOC_OBJECTID)
826 ret = btrfs_inc_ref(trans, root, cow, 1, 1);
828 ret = btrfs_inc_ref(trans, root, cow, 0, 1);
829 BUG_ON(ret); /* -ENOMEM */
831 if (new_flags != 0) {
832 ret = btrfs_set_disk_extent_flags(trans, root,
840 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
841 if (root->root_key.objectid ==
842 BTRFS_TREE_RELOC_OBJECTID)
843 ret = btrfs_inc_ref(trans, root, cow, 1, 1);
845 ret = btrfs_inc_ref(trans, root, cow, 0, 1);
846 BUG_ON(ret); /* -ENOMEM */
847 ret = btrfs_dec_ref(trans, root, buf, 1, 1);
848 BUG_ON(ret); /* -ENOMEM */
851 * don't log freeing in case we're freeing the root node, this
852 * is done by tree_mod_log_set_root_pointer later
854 if (buf != root->node && btrfs_header_level(buf) != 0)
855 tree_mod_log_free_eb(root->fs_info, buf);
856 clean_tree_block(trans, root, buf);
863 * does the dirty work in cow of a single block. The parent block (if
864 * supplied) is updated to point to the new cow copy. The new buffer is marked
865 * dirty and returned locked. If you modify the block it needs to be marked
868 * search_start -- an allocation hint for the new block
870 * empty_size -- a hint that you plan on doing more cow. This is the size in
871 * bytes the allocator should try to find free next to the block it returns.
872 * This is just a hint and may be ignored by the allocator.
874 static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
875 struct btrfs_root *root,
876 struct extent_buffer *buf,
877 struct extent_buffer *parent, int parent_slot,
878 struct extent_buffer **cow_ret,
879 u64 search_start, u64 empty_size)
881 struct btrfs_disk_key disk_key;
882 struct extent_buffer *cow;
891 btrfs_assert_tree_locked(buf);
893 WARN_ON(root->ref_cows && trans->transid !=
894 root->fs_info->running_transaction->transid);
895 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
897 level = btrfs_header_level(buf);
900 btrfs_item_key(buf, &disk_key, 0);
902 btrfs_node_key(buf, &disk_key, 0);
904 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
906 parent_start = parent->start;
912 cow = btrfs_alloc_free_block(trans, root, buf->len, parent_start,
913 root->root_key.objectid, &disk_key,
914 level, search_start, empty_size);
918 /* cow is set to blocking by btrfs_init_new_buffer */
920 copy_extent_buffer(cow, buf, 0, 0, cow->len);
921 btrfs_set_header_bytenr(cow, cow->start);
922 btrfs_set_header_generation(cow, trans->transid);
923 btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV);
924 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN |
925 BTRFS_HEADER_FLAG_RELOC);
926 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
927 btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC);
929 btrfs_set_header_owner(cow, root->root_key.objectid);
931 write_extent_buffer(cow, root->fs_info->fsid,
932 (unsigned long)btrfs_header_fsid(cow),
935 ret = update_ref_for_cow(trans, root, buf, cow, &last_ref);
937 btrfs_abort_transaction(trans, root, ret);
942 btrfs_reloc_cow_block(trans, root, buf, cow);
944 if (buf == root->node) {
945 WARN_ON(parent && parent != buf);
946 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
947 btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
948 parent_start = buf->start;
952 extent_buffer_get(cow);
953 tree_mod_log_set_root_pointer(root, cow);
954 rcu_assign_pointer(root->node, cow);
956 btrfs_free_tree_block(trans, root, buf, parent_start,
958 free_extent_buffer(buf);
959 add_root_to_dirty_list(root);
961 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
962 parent_start = parent->start;
966 WARN_ON(trans->transid != btrfs_header_generation(parent));
967 tree_mod_log_insert_key(root->fs_info, parent, parent_slot,
968 MOD_LOG_KEY_REPLACE);
969 btrfs_set_node_blockptr(parent, parent_slot,
971 btrfs_set_node_ptr_generation(parent, parent_slot,
973 btrfs_mark_buffer_dirty(parent);
974 btrfs_free_tree_block(trans, root, buf, parent_start,
978 btrfs_tree_unlock(buf);
979 free_extent_buffer_stale(buf);
980 btrfs_mark_buffer_dirty(cow);
986 * returns the logical address of the oldest predecessor of the given root.
987 * entries older than time_seq are ignored.
989 static struct tree_mod_elem *
990 __tree_mod_log_oldest_root(struct btrfs_fs_info *fs_info,
991 struct btrfs_root *root, u64 time_seq)
993 struct tree_mod_elem *tm;
994 struct tree_mod_elem *found = NULL;
995 u64 root_logical = root->node->start;
1002 * the very last operation that's logged for a root is the replacement
1003 * operation (if it is replaced at all). this has the index of the *new*
1004 * root, making it the very first operation that's logged for this root.
1007 tm = tree_mod_log_search_oldest(fs_info, root_logical,
1012 * we must have key remove operations in the log before the
1013 * replace operation.
1017 if (tm->op != MOD_LOG_ROOT_REPLACE)
1021 root_logical = tm->old_root.logical;
1022 BUG_ON(root_logical == root->node->start);
1030 * tm is a pointer to the first operation to rewind within eb. then, all
1031 * previous operations will be rewinded (until we reach something older than
1035 __tree_mod_log_rewind(struct extent_buffer *eb, u64 time_seq,
1036 struct tree_mod_elem *first_tm)
1039 struct rb_node *next;
1040 struct tree_mod_elem *tm = first_tm;
1041 unsigned long o_dst;
1042 unsigned long o_src;
1043 unsigned long p_size = sizeof(struct btrfs_key_ptr);
1045 n = btrfs_header_nritems(eb);
1046 while (tm && tm->elem.seq >= time_seq) {
1048 * all the operations are recorded with the operator used for
1049 * the modification. as we're going backwards, we do the
1050 * opposite of each operation here.
1053 case MOD_LOG_KEY_REMOVE_WHILE_FREEING:
1054 BUG_ON(tm->slot < n);
1055 case MOD_LOG_KEY_REMOVE_WHILE_MOVING:
1056 case MOD_LOG_KEY_REMOVE:
1057 btrfs_set_node_key(eb, &tm->key, tm->slot);
1058 btrfs_set_node_blockptr(eb, tm->slot, tm->blockptr);
1059 btrfs_set_node_ptr_generation(eb, tm->slot,
1063 case MOD_LOG_KEY_REPLACE:
1064 BUG_ON(tm->slot >= n);
1065 btrfs_set_node_key(eb, &tm->key, tm->slot);
1066 btrfs_set_node_blockptr(eb, tm->slot, tm->blockptr);
1067 btrfs_set_node_ptr_generation(eb, tm->slot,
1070 case MOD_LOG_KEY_ADD:
1071 if (tm->slot != n - 1) {
1072 o_dst = btrfs_node_key_ptr_offset(tm->slot);
1073 o_src = btrfs_node_key_ptr_offset(tm->slot + 1);
1074 memmove_extent_buffer(eb, o_dst, o_src, p_size);
1078 case MOD_LOG_MOVE_KEYS:
1079 o_dst = btrfs_node_key_ptr_offset(tm->slot);
1080 o_src = btrfs_node_key_ptr_offset(tm->move.dst_slot);
1081 memmove_extent_buffer(eb, o_dst, o_src,
1082 tm->move.nr_items * p_size);
1084 case MOD_LOG_ROOT_REPLACE:
1086 * this operation is special. for roots, this must be
1087 * handled explicitly before rewinding.
1088 * for non-roots, this operation may exist if the node
1089 * was a root: root A -> child B; then A gets empty and
1090 * B is promoted to the new root. in the mod log, we'll
1091 * have a root-replace operation for B, a tree block
1092 * that is no root. we simply ignore that operation.
1096 next = rb_next(&tm->node);
1099 tm = container_of(next, struct tree_mod_elem, node);
1100 if (tm->index != first_tm->index)
1103 btrfs_set_header_nritems(eb, n);
1106 static struct extent_buffer *
1107 tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct extent_buffer *eb,
1110 struct extent_buffer *eb_rewin;
1111 struct tree_mod_elem *tm;
1116 if (btrfs_header_level(eb) == 0)
1119 tm = tree_mod_log_search(fs_info, eb->start, time_seq);
1123 if (tm->op == MOD_LOG_KEY_REMOVE_WHILE_FREEING) {
1124 BUG_ON(tm->slot != 0);
1125 eb_rewin = alloc_dummy_extent_buffer(eb->start,
1126 fs_info->tree_root->nodesize);
1128 btrfs_set_header_bytenr(eb_rewin, eb->start);
1129 btrfs_set_header_backref_rev(eb_rewin,
1130 btrfs_header_backref_rev(eb));
1131 btrfs_set_header_owner(eb_rewin, btrfs_header_owner(eb));
1132 btrfs_set_header_level(eb_rewin, btrfs_header_level(eb));
1134 eb_rewin = btrfs_clone_extent_buffer(eb);
1138 extent_buffer_get(eb_rewin);
1139 free_extent_buffer(eb);
1141 __tree_mod_log_rewind(eb_rewin, time_seq, tm);
1146 static inline struct extent_buffer *
1147 get_old_root(struct btrfs_root *root, u64 time_seq)
1149 struct tree_mod_elem *tm;
1150 struct extent_buffer *eb;
1151 struct tree_mod_root *old_root;
1154 tm = __tree_mod_log_oldest_root(root->fs_info, root, time_seq);
1158 old_root = &tm->old_root;
1159 old_generation = tm->generation;
1161 tm = tree_mod_log_search(root->fs_info, old_root->logical, time_seq);
1163 * there was an item in the log when __tree_mod_log_oldest_root
1164 * returned. this one must not go away, because the time_seq passed to
1165 * us must be blocking its removal.
1169 if (old_root->logical == root->node->start) {
1170 /* there are logged operations for the current root */
1171 eb = btrfs_clone_extent_buffer(root->node);
1173 /* there's a root replace operation for the current root */
1174 eb = alloc_dummy_extent_buffer(tm->index << PAGE_CACHE_SHIFT,
1176 btrfs_set_header_bytenr(eb, eb->start);
1177 btrfs_set_header_backref_rev(eb, BTRFS_MIXED_BACKREF_REV);
1178 btrfs_set_header_owner(eb, root->root_key.objectid);
1182 btrfs_set_header_level(eb, old_root->level);
1183 btrfs_set_header_generation(eb, old_generation);
1184 __tree_mod_log_rewind(eb, time_seq, tm);
1189 static inline int should_cow_block(struct btrfs_trans_handle *trans,
1190 struct btrfs_root *root,
1191 struct extent_buffer *buf)
1193 /* ensure we can see the force_cow */
1197 * We do not need to cow a block if
1198 * 1) this block is not created or changed in this transaction;
1199 * 2) this block does not belong to TREE_RELOC tree;
1200 * 3) the root is not forced COW.
1202 * What is forced COW:
1203 * when we create snapshot during commiting the transaction,
1204 * after we've finished coping src root, we must COW the shared
1205 * block to ensure the metadata consistency.
1207 if (btrfs_header_generation(buf) == trans->transid &&
1208 !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN) &&
1209 !(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID &&
1210 btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)) &&
1217 * cows a single block, see __btrfs_cow_block for the real work.
1218 * This version of it has extra checks so that a block isn't cow'd more than
1219 * once per transaction, as long as it hasn't been written yet
1221 noinline int btrfs_cow_block(struct btrfs_trans_handle *trans,
1222 struct btrfs_root *root, struct extent_buffer *buf,
1223 struct extent_buffer *parent, int parent_slot,
1224 struct extent_buffer **cow_ret)
1229 if (trans->transaction != root->fs_info->running_transaction) {
1230 printk(KERN_CRIT "trans %llu running %llu\n",
1231 (unsigned long long)trans->transid,
1232 (unsigned long long)
1233 root->fs_info->running_transaction->transid);
1236 if (trans->transid != root->fs_info->generation) {
1237 printk(KERN_CRIT "trans %llu running %llu\n",
1238 (unsigned long long)trans->transid,
1239 (unsigned long long)root->fs_info->generation);
1243 if (!should_cow_block(trans, root, buf)) {
1248 search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1);
1251 btrfs_set_lock_blocking(parent);
1252 btrfs_set_lock_blocking(buf);
1254 ret = __btrfs_cow_block(trans, root, buf, parent,
1255 parent_slot, cow_ret, search_start, 0);
1257 trace_btrfs_cow_block(root, buf, *cow_ret);
1263 * helper function for defrag to decide if two blocks pointed to by a
1264 * node are actually close by
1266 static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
1268 if (blocknr < other && other - (blocknr + blocksize) < 32768)
1270 if (blocknr > other && blocknr - (other + blocksize) < 32768)
1276 * compare two keys in a memcmp fashion
1278 static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
1280 struct btrfs_key k1;
1282 btrfs_disk_key_to_cpu(&k1, disk);
1284 return btrfs_comp_cpu_keys(&k1, k2);
1288 * same as comp_keys only with two btrfs_key's
1290 int btrfs_comp_cpu_keys(struct btrfs_key *k1, struct btrfs_key *k2)
1292 if (k1->objectid > k2->objectid)
1294 if (k1->objectid < k2->objectid)
1296 if (k1->type > k2->type)
1298 if (k1->type < k2->type)
1300 if (k1->offset > k2->offset)
1302 if (k1->offset < k2->offset)
1308 * this is used by the defrag code to go through all the
1309 * leaves pointed to by a node and reallocate them so that
1310 * disk order is close to key order
1312 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
1313 struct btrfs_root *root, struct extent_buffer *parent,
1314 int start_slot, int cache_only, u64 *last_ret,
1315 struct btrfs_key *progress)
1317 struct extent_buffer *cur;
1320 u64 search_start = *last_ret;
1330 int progress_passed = 0;
1331 struct btrfs_disk_key disk_key;
1333 parent_level = btrfs_header_level(parent);
1334 if (cache_only && parent_level != 1)
1337 if (trans->transaction != root->fs_info->running_transaction)
1339 if (trans->transid != root->fs_info->generation)
1342 parent_nritems = btrfs_header_nritems(parent);
1343 blocksize = btrfs_level_size(root, parent_level - 1);
1344 end_slot = parent_nritems;
1346 if (parent_nritems == 1)
1349 btrfs_set_lock_blocking(parent);
1351 for (i = start_slot; i < end_slot; i++) {
1354 btrfs_node_key(parent, &disk_key, i);
1355 if (!progress_passed && comp_keys(&disk_key, progress) < 0)
1358 progress_passed = 1;
1359 blocknr = btrfs_node_blockptr(parent, i);
1360 gen = btrfs_node_ptr_generation(parent, i);
1361 if (last_block == 0)
1362 last_block = blocknr;
1365 other = btrfs_node_blockptr(parent, i - 1);
1366 close = close_blocks(blocknr, other, blocksize);
1368 if (!close && i < end_slot - 2) {
1369 other = btrfs_node_blockptr(parent, i + 1);
1370 close = close_blocks(blocknr, other, blocksize);
1373 last_block = blocknr;
1377 cur = btrfs_find_tree_block(root, blocknr, blocksize);
1379 uptodate = btrfs_buffer_uptodate(cur, gen, 0);
1382 if (!cur || !uptodate) {
1384 free_extent_buffer(cur);
1388 cur = read_tree_block(root, blocknr,
1392 } else if (!uptodate) {
1393 err = btrfs_read_buffer(cur, gen);
1395 free_extent_buffer(cur);
1400 if (search_start == 0)
1401 search_start = last_block;
1403 btrfs_tree_lock(cur);
1404 btrfs_set_lock_blocking(cur);
1405 err = __btrfs_cow_block(trans, root, cur, parent, i,
1408 (end_slot - i) * blocksize));
1410 btrfs_tree_unlock(cur);
1411 free_extent_buffer(cur);
1414 search_start = cur->start;
1415 last_block = cur->start;
1416 *last_ret = search_start;
1417 btrfs_tree_unlock(cur);
1418 free_extent_buffer(cur);
1424 * The leaf data grows from end-to-front in the node.
1425 * this returns the address of the start of the last item,
1426 * which is the stop of the leaf data stack
1428 static inline unsigned int leaf_data_end(struct btrfs_root *root,
1429 struct extent_buffer *leaf)
1431 u32 nr = btrfs_header_nritems(leaf);
1433 return BTRFS_LEAF_DATA_SIZE(root);
1434 return btrfs_item_offset_nr(leaf, nr - 1);
1439 * search for key in the extent_buffer. The items start at offset p,
1440 * and they are item_size apart. There are 'max' items in p.
1442 * the slot in the array is returned via slot, and it points to
1443 * the place where you would insert key if it is not found in
1446 * slot may point to max if the key is bigger than all of the keys
1448 static noinline int generic_bin_search(struct extent_buffer *eb,
1450 int item_size, struct btrfs_key *key,
1457 struct btrfs_disk_key *tmp = NULL;
1458 struct btrfs_disk_key unaligned;
1459 unsigned long offset;
1461 unsigned long map_start = 0;
1462 unsigned long map_len = 0;
1465 while (low < high) {
1466 mid = (low + high) / 2;
1467 offset = p + mid * item_size;
1469 if (!kaddr || offset < map_start ||
1470 (offset + sizeof(struct btrfs_disk_key)) >
1471 map_start + map_len) {
1473 err = map_private_extent_buffer(eb, offset,
1474 sizeof(struct btrfs_disk_key),
1475 &kaddr, &map_start, &map_len);
1478 tmp = (struct btrfs_disk_key *)(kaddr + offset -
1481 read_extent_buffer(eb, &unaligned,
1482 offset, sizeof(unaligned));
1487 tmp = (struct btrfs_disk_key *)(kaddr + offset -
1490 ret = comp_keys(tmp, key);
1506 * simple bin_search frontend that does the right thing for
1509 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
1510 int level, int *slot)
1513 return generic_bin_search(eb,
1514 offsetof(struct btrfs_leaf, items),
1515 sizeof(struct btrfs_item),
1516 key, btrfs_header_nritems(eb),
1519 return generic_bin_search(eb,
1520 offsetof(struct btrfs_node, ptrs),
1521 sizeof(struct btrfs_key_ptr),
1522 key, btrfs_header_nritems(eb),
1526 int btrfs_bin_search(struct extent_buffer *eb, struct btrfs_key *key,
1527 int level, int *slot)
1529 return bin_search(eb, key, level, slot);
1532 static void root_add_used(struct btrfs_root *root, u32 size)
1534 spin_lock(&root->accounting_lock);
1535 btrfs_set_root_used(&root->root_item,
1536 btrfs_root_used(&root->root_item) + size);
1537 spin_unlock(&root->accounting_lock);
1540 static void root_sub_used(struct btrfs_root *root, u32 size)
1542 spin_lock(&root->accounting_lock);
1543 btrfs_set_root_used(&root->root_item,
1544 btrfs_root_used(&root->root_item) - size);
1545 spin_unlock(&root->accounting_lock);
1548 /* given a node and slot number, this reads the blocks it points to. The
1549 * extent buffer is returned with a reference taken (but unlocked).
1550 * NULL is returned on error.
1552 static noinline struct extent_buffer *read_node_slot(struct btrfs_root *root,
1553 struct extent_buffer *parent, int slot)
1555 int level = btrfs_header_level(parent);
1558 if (slot >= btrfs_header_nritems(parent))
1563 return read_tree_block(root, btrfs_node_blockptr(parent, slot),
1564 btrfs_level_size(root, level - 1),
1565 btrfs_node_ptr_generation(parent, slot));
1569 * node level balancing, used to make sure nodes are in proper order for
1570 * item deletion. We balance from the top down, so we have to make sure
1571 * that a deletion won't leave an node completely empty later on.
1573 static noinline int balance_level(struct btrfs_trans_handle *trans,
1574 struct btrfs_root *root,
1575 struct btrfs_path *path, int level)
1577 struct extent_buffer *right = NULL;
1578 struct extent_buffer *mid;
1579 struct extent_buffer *left = NULL;
1580 struct extent_buffer *parent = NULL;
1584 int orig_slot = path->slots[level];
1590 mid = path->nodes[level];
1592 WARN_ON(path->locks[level] != BTRFS_WRITE_LOCK &&
1593 path->locks[level] != BTRFS_WRITE_LOCK_BLOCKING);
1594 WARN_ON(btrfs_header_generation(mid) != trans->transid);
1596 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
1598 if (level < BTRFS_MAX_LEVEL - 1) {
1599 parent = path->nodes[level + 1];
1600 pslot = path->slots[level + 1];
1604 * deal with the case where there is only one pointer in the root
1605 * by promoting the node below to a root
1608 struct extent_buffer *child;
1610 if (btrfs_header_nritems(mid) != 1)
1613 /* promote the child to a root */
1614 child = read_node_slot(root, mid, 0);
1617 btrfs_std_error(root->fs_info, ret);
1621 btrfs_tree_lock(child);
1622 btrfs_set_lock_blocking(child);
1623 ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
1625 btrfs_tree_unlock(child);
1626 free_extent_buffer(child);
1630 tree_mod_log_set_root_pointer(root, child);
1631 rcu_assign_pointer(root->node, child);
1633 add_root_to_dirty_list(root);
1634 btrfs_tree_unlock(child);
1636 path->locks[level] = 0;
1637 path->nodes[level] = NULL;
1638 clean_tree_block(trans, root, mid);
1639 btrfs_tree_unlock(mid);
1640 /* once for the path */
1641 free_extent_buffer(mid);
1643 root_sub_used(root, mid->len);
1644 btrfs_free_tree_block(trans, root, mid, 0, 1);
1645 /* once for the root ptr */
1646 free_extent_buffer_stale(mid);
1649 if (btrfs_header_nritems(mid) >
1650 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
1653 btrfs_header_nritems(mid);
1655 left = read_node_slot(root, parent, pslot - 1);
1657 btrfs_tree_lock(left);
1658 btrfs_set_lock_blocking(left);
1659 wret = btrfs_cow_block(trans, root, left,
1660 parent, pslot - 1, &left);
1666 right = read_node_slot(root, parent, pslot + 1);
1668 btrfs_tree_lock(right);
1669 btrfs_set_lock_blocking(right);
1670 wret = btrfs_cow_block(trans, root, right,
1671 parent, pslot + 1, &right);
1678 /* first, try to make some room in the middle buffer */
1680 orig_slot += btrfs_header_nritems(left);
1681 wret = push_node_left(trans, root, left, mid, 1);
1684 btrfs_header_nritems(mid);
1688 * then try to empty the right most buffer into the middle
1691 wret = push_node_left(trans, root, mid, right, 1);
1692 if (wret < 0 && wret != -ENOSPC)
1694 if (btrfs_header_nritems(right) == 0) {
1695 clean_tree_block(trans, root, right);
1696 btrfs_tree_unlock(right);
1697 del_ptr(trans, root, path, level + 1, pslot + 1, 1);
1698 root_sub_used(root, right->len);
1699 btrfs_free_tree_block(trans, root, right, 0, 1);
1700 free_extent_buffer_stale(right);
1703 struct btrfs_disk_key right_key;
1704 btrfs_node_key(right, &right_key, 0);
1705 tree_mod_log_set_node_key(root->fs_info, parent,
1706 &right_key, pslot + 1, 0);
1707 btrfs_set_node_key(parent, &right_key, pslot + 1);
1708 btrfs_mark_buffer_dirty(parent);
1711 if (btrfs_header_nritems(mid) == 1) {
1713 * we're not allowed to leave a node with one item in the
1714 * tree during a delete. A deletion from lower in the tree
1715 * could try to delete the only pointer in this node.
1716 * So, pull some keys from the left.
1717 * There has to be a left pointer at this point because
1718 * otherwise we would have pulled some pointers from the
1723 btrfs_std_error(root->fs_info, ret);
1726 wret = balance_node_right(trans, root, mid, left);
1732 wret = push_node_left(trans, root, left, mid, 1);
1738 if (btrfs_header_nritems(mid) == 0) {
1739 clean_tree_block(trans, root, mid);
1740 btrfs_tree_unlock(mid);
1741 del_ptr(trans, root, path, level + 1, pslot, 1);
1742 root_sub_used(root, mid->len);
1743 btrfs_free_tree_block(trans, root, mid, 0, 1);
1744 free_extent_buffer_stale(mid);
1747 /* update the parent key to reflect our changes */
1748 struct btrfs_disk_key mid_key;
1749 btrfs_node_key(mid, &mid_key, 0);
1750 tree_mod_log_set_node_key(root->fs_info, parent, &mid_key,
1752 btrfs_set_node_key(parent, &mid_key, pslot);
1753 btrfs_mark_buffer_dirty(parent);
1756 /* update the path */
1758 if (btrfs_header_nritems(left) > orig_slot) {
1759 extent_buffer_get(left);
1760 /* left was locked after cow */
1761 path->nodes[level] = left;
1762 path->slots[level + 1] -= 1;
1763 path->slots[level] = orig_slot;
1765 btrfs_tree_unlock(mid);
1766 free_extent_buffer(mid);
1769 orig_slot -= btrfs_header_nritems(left);
1770 path->slots[level] = orig_slot;
1773 /* double check we haven't messed things up */
1775 btrfs_node_blockptr(path->nodes[level], path->slots[level]))
1779 btrfs_tree_unlock(right);
1780 free_extent_buffer(right);
1783 if (path->nodes[level] != left)
1784 btrfs_tree_unlock(left);
1785 free_extent_buffer(left);
1790 /* Node balancing for insertion. Here we only split or push nodes around
1791 * when they are completely full. This is also done top down, so we
1792 * have to be pessimistic.
1794 static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
1795 struct btrfs_root *root,
1796 struct btrfs_path *path, int level)
1798 struct extent_buffer *right = NULL;
1799 struct extent_buffer *mid;
1800 struct extent_buffer *left = NULL;
1801 struct extent_buffer *parent = NULL;
1805 int orig_slot = path->slots[level];
1810 mid = path->nodes[level];
1811 WARN_ON(btrfs_header_generation(mid) != trans->transid);
1813 if (level < BTRFS_MAX_LEVEL - 1) {
1814 parent = path->nodes[level + 1];
1815 pslot = path->slots[level + 1];
1821 left = read_node_slot(root, parent, pslot - 1);
1823 /* first, try to make some room in the middle buffer */
1827 btrfs_tree_lock(left);
1828 btrfs_set_lock_blocking(left);
1830 left_nr = btrfs_header_nritems(left);
1831 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1834 ret = btrfs_cow_block(trans, root, left, parent,
1839 wret = push_node_left(trans, root,
1846 struct btrfs_disk_key disk_key;
1847 orig_slot += left_nr;
1848 btrfs_node_key(mid, &disk_key, 0);
1849 tree_mod_log_set_node_key(root->fs_info, parent,
1850 &disk_key, pslot, 0);
1851 btrfs_set_node_key(parent, &disk_key, pslot);
1852 btrfs_mark_buffer_dirty(parent);
1853 if (btrfs_header_nritems(left) > orig_slot) {
1854 path->nodes[level] = left;
1855 path->slots[level + 1] -= 1;
1856 path->slots[level] = orig_slot;
1857 btrfs_tree_unlock(mid);
1858 free_extent_buffer(mid);
1861 btrfs_header_nritems(left);
1862 path->slots[level] = orig_slot;
1863 btrfs_tree_unlock(left);
1864 free_extent_buffer(left);
1868 btrfs_tree_unlock(left);
1869 free_extent_buffer(left);
1871 right = read_node_slot(root, parent, pslot + 1);
1874 * then try to empty the right most buffer into the middle
1879 btrfs_tree_lock(right);
1880 btrfs_set_lock_blocking(right);
1882 right_nr = btrfs_header_nritems(right);
1883 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1886 ret = btrfs_cow_block(trans, root, right,
1892 wret = balance_node_right(trans, root,
1899 struct btrfs_disk_key disk_key;
1901 btrfs_node_key(right, &disk_key, 0);
1902 tree_mod_log_set_node_key(root->fs_info, parent,
1903 &disk_key, pslot + 1, 0);
1904 btrfs_set_node_key(parent, &disk_key, pslot + 1);
1905 btrfs_mark_buffer_dirty(parent);
1907 if (btrfs_header_nritems(mid) <= orig_slot) {
1908 path->nodes[level] = right;
1909 path->slots[level + 1] += 1;
1910 path->slots[level] = orig_slot -
1911 btrfs_header_nritems(mid);
1912 btrfs_tree_unlock(mid);
1913 free_extent_buffer(mid);
1915 btrfs_tree_unlock(right);
1916 free_extent_buffer(right);
1920 btrfs_tree_unlock(right);
1921 free_extent_buffer(right);
1927 * readahead one full node of leaves, finding things that are close
1928 * to the block in 'slot', and triggering ra on them.
1930 static void reada_for_search(struct btrfs_root *root,
1931 struct btrfs_path *path,
1932 int level, int slot, u64 objectid)
1934 struct extent_buffer *node;
1935 struct btrfs_disk_key disk_key;
1941 int direction = path->reada;
1942 struct extent_buffer *eb;
1950 if (!path->nodes[level])
1953 node = path->nodes[level];
1955 search = btrfs_node_blockptr(node, slot);
1956 blocksize = btrfs_level_size(root, level - 1);
1957 eb = btrfs_find_tree_block(root, search, blocksize);
1959 free_extent_buffer(eb);
1965 nritems = btrfs_header_nritems(node);
1969 if (direction < 0) {
1973 } else if (direction > 0) {
1978 if (path->reada < 0 && objectid) {
1979 btrfs_node_key(node, &disk_key, nr);
1980 if (btrfs_disk_key_objectid(&disk_key) != objectid)
1983 search = btrfs_node_blockptr(node, nr);
1984 if ((search <= target && target - search <= 65536) ||
1985 (search > target && search - target <= 65536)) {
1986 gen = btrfs_node_ptr_generation(node, nr);
1987 readahead_tree_block(root, search, blocksize, gen);
1991 if ((nread > 65536 || nscan > 32))
1997 * returns -EAGAIN if it had to drop the path, or zero if everything was in
2000 static noinline int reada_for_balance(struct btrfs_root *root,
2001 struct btrfs_path *path, int level)
2005 struct extent_buffer *parent;
2006 struct extent_buffer *eb;
2013 parent = path->nodes[level + 1];
2017 nritems = btrfs_header_nritems(parent);
2018 slot = path->slots[level + 1];
2019 blocksize = btrfs_level_size(root, level);
2022 block1 = btrfs_node_blockptr(parent, slot - 1);
2023 gen = btrfs_node_ptr_generation(parent, slot - 1);
2024 eb = btrfs_find_tree_block(root, block1, blocksize);
2026 * if we get -eagain from btrfs_buffer_uptodate, we
2027 * don't want to return eagain here. That will loop
2030 if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0)
2032 free_extent_buffer(eb);
2034 if (slot + 1 < nritems) {
2035 block2 = btrfs_node_blockptr(parent, slot + 1);
2036 gen = btrfs_node_ptr_generation(parent, slot + 1);
2037 eb = btrfs_find_tree_block(root, block2, blocksize);
2038 if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0)
2040 free_extent_buffer(eb);
2042 if (block1 || block2) {
2045 /* release the whole path */
2046 btrfs_release_path(path);
2048 /* read the blocks */
2050 readahead_tree_block(root, block1, blocksize, 0);
2052 readahead_tree_block(root, block2, blocksize, 0);
2055 eb = read_tree_block(root, block1, blocksize, 0);
2056 free_extent_buffer(eb);
2059 eb = read_tree_block(root, block2, blocksize, 0);
2060 free_extent_buffer(eb);
2068 * when we walk down the tree, it is usually safe to unlock the higher layers
2069 * in the tree. The exceptions are when our path goes through slot 0, because
2070 * operations on the tree might require changing key pointers higher up in the
2073 * callers might also have set path->keep_locks, which tells this code to keep
2074 * the lock if the path points to the last slot in the block. This is part of
2075 * walking through the tree, and selecting the next slot in the higher block.
2077 * lowest_unlock sets the lowest level in the tree we're allowed to unlock. so
2078 * if lowest_unlock is 1, level 0 won't be unlocked
2080 static noinline void unlock_up(struct btrfs_path *path, int level,
2081 int lowest_unlock, int min_write_lock_level,
2082 int *write_lock_level)
2085 int skip_level = level;
2087 struct extent_buffer *t;
2089 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
2090 if (!path->nodes[i])
2092 if (!path->locks[i])
2094 if (!no_skips && path->slots[i] == 0) {
2098 if (!no_skips && path->keep_locks) {
2101 nritems = btrfs_header_nritems(t);
2102 if (nritems < 1 || path->slots[i] >= nritems - 1) {
2107 if (skip_level < i && i >= lowest_unlock)
2111 if (i >= lowest_unlock && i > skip_level && path->locks[i]) {
2112 btrfs_tree_unlock_rw(t, path->locks[i]);
2114 if (write_lock_level &&
2115 i > min_write_lock_level &&
2116 i <= *write_lock_level) {
2117 *write_lock_level = i - 1;
2124 * This releases any locks held in the path starting at level and
2125 * going all the way up to the root.
2127 * btrfs_search_slot will keep the lock held on higher nodes in a few
2128 * corner cases, such as COW of the block at slot zero in the node. This
2129 * ignores those rules, and it should only be called when there are no
2130 * more updates to be done higher up in the tree.
2132 noinline void btrfs_unlock_up_safe(struct btrfs_path *path, int level)
2136 if (path->keep_locks)
2139 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
2140 if (!path->nodes[i])
2142 if (!path->locks[i])
2144 btrfs_tree_unlock_rw(path->nodes[i], path->locks[i]);
2150 * helper function for btrfs_search_slot. The goal is to find a block
2151 * in cache without setting the path to blocking. If we find the block
2152 * we return zero and the path is unchanged.
2154 * If we can't find the block, we set the path blocking and do some
2155 * reada. -EAGAIN is returned and the search must be repeated.
2158 read_block_for_search(struct btrfs_trans_handle *trans,
2159 struct btrfs_root *root, struct btrfs_path *p,
2160 struct extent_buffer **eb_ret, int level, int slot,
2161 struct btrfs_key *key, u64 time_seq)
2166 struct extent_buffer *b = *eb_ret;
2167 struct extent_buffer *tmp;
2170 blocknr = btrfs_node_blockptr(b, slot);
2171 gen = btrfs_node_ptr_generation(b, slot);
2172 blocksize = btrfs_level_size(root, level - 1);
2174 tmp = btrfs_find_tree_block(root, blocknr, blocksize);
2176 /* first we do an atomic uptodate check */
2177 if (btrfs_buffer_uptodate(tmp, 0, 1) > 0) {
2178 if (btrfs_buffer_uptodate(tmp, gen, 1) > 0) {
2180 * we found an up to date block without
2187 /* the pages were up to date, but we failed
2188 * the generation number check. Do a full
2189 * read for the generation number that is correct.
2190 * We must do this without dropping locks so
2191 * we can trust our generation number
2193 free_extent_buffer(tmp);
2194 btrfs_set_path_blocking(p);
2196 /* now we're allowed to do a blocking uptodate check */
2197 tmp = read_tree_block(root, blocknr, blocksize, gen);
2198 if (tmp && btrfs_buffer_uptodate(tmp, gen, 0) > 0) {
2202 free_extent_buffer(tmp);
2203 btrfs_release_path(p);
2209 * reduce lock contention at high levels
2210 * of the btree by dropping locks before
2211 * we read. Don't release the lock on the current
2212 * level because we need to walk this node to figure
2213 * out which blocks to read.
2215 btrfs_unlock_up_safe(p, level + 1);
2216 btrfs_set_path_blocking(p);
2218 free_extent_buffer(tmp);
2220 reada_for_search(root, p, level, slot, key->objectid);
2222 btrfs_release_path(p);
2225 tmp = read_tree_block(root, blocknr, blocksize, 0);
2228 * If the read above didn't mark this buffer up to date,
2229 * it will never end up being up to date. Set ret to EIO now
2230 * and give up so that our caller doesn't loop forever
2233 if (!btrfs_buffer_uptodate(tmp, 0, 0))
2235 free_extent_buffer(tmp);
2241 * helper function for btrfs_search_slot. This does all of the checks
2242 * for node-level blocks and does any balancing required based on
2245 * If no extra work was required, zero is returned. If we had to
2246 * drop the path, -EAGAIN is returned and btrfs_search_slot must
2250 setup_nodes_for_search(struct btrfs_trans_handle *trans,
2251 struct btrfs_root *root, struct btrfs_path *p,
2252 struct extent_buffer *b, int level, int ins_len,
2253 int *write_lock_level)
2256 if ((p->search_for_split || ins_len > 0) && btrfs_header_nritems(b) >=
2257 BTRFS_NODEPTRS_PER_BLOCK(root) - 3) {
2260 if (*write_lock_level < level + 1) {
2261 *write_lock_level = level + 1;
2262 btrfs_release_path(p);
2266 sret = reada_for_balance(root, p, level);
2270 btrfs_set_path_blocking(p);
2271 sret = split_node(trans, root, p, level);
2272 btrfs_clear_path_blocking(p, NULL, 0);
2279 b = p->nodes[level];
2280 } else if (ins_len < 0 && btrfs_header_nritems(b) <
2281 BTRFS_NODEPTRS_PER_BLOCK(root) / 2) {
2284 if (*write_lock_level < level + 1) {
2285 *write_lock_level = level + 1;
2286 btrfs_release_path(p);
2290 sret = reada_for_balance(root, p, level);
2294 btrfs_set_path_blocking(p);
2295 sret = balance_level(trans, root, p, level);
2296 btrfs_clear_path_blocking(p, NULL, 0);
2302 b = p->nodes[level];
2304 btrfs_release_path(p);
2307 BUG_ON(btrfs_header_nritems(b) == 1);
2318 * look for key in the tree. path is filled in with nodes along the way
2319 * if key is found, we return zero and you can find the item in the leaf
2320 * level of the path (level 0)
2322 * If the key isn't found, the path points to the slot where it should
2323 * be inserted, and 1 is returned. If there are other errors during the
2324 * search a negative error number is returned.
2326 * if ins_len > 0, nodes and leaves will be split as we walk down the
2327 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
2330 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
2331 *root, struct btrfs_key *key, struct btrfs_path *p, int
2334 struct extent_buffer *b;
2339 int lowest_unlock = 1;
2341 /* everything at write_lock_level or lower must be write locked */
2342 int write_lock_level = 0;
2343 u8 lowest_level = 0;
2344 int min_write_lock_level;
2346 lowest_level = p->lowest_level;
2347 WARN_ON(lowest_level && ins_len > 0);
2348 WARN_ON(p->nodes[0] != NULL);
2353 /* when we are removing items, we might have to go up to level
2354 * two as we update tree pointers Make sure we keep write
2355 * for those levels as well
2357 write_lock_level = 2;
2358 } else if (ins_len > 0) {
2360 * for inserting items, make sure we have a write lock on
2361 * level 1 so we can update keys
2363 write_lock_level = 1;
2367 write_lock_level = -1;
2369 if (cow && (p->keep_locks || p->lowest_level))
2370 write_lock_level = BTRFS_MAX_LEVEL;
2372 min_write_lock_level = write_lock_level;
2376 * we try very hard to do read locks on the root
2378 root_lock = BTRFS_READ_LOCK;
2380 if (p->search_commit_root) {
2382 * the commit roots are read only
2383 * so we always do read locks
2385 b = root->commit_root;
2386 extent_buffer_get(b);
2387 level = btrfs_header_level(b);
2388 if (!p->skip_locking)
2389 btrfs_tree_read_lock(b);
2391 if (p->skip_locking) {
2392 b = btrfs_root_node(root);
2393 level = btrfs_header_level(b);
2395 /* we don't know the level of the root node
2396 * until we actually have it read locked
2398 b = btrfs_read_lock_root_node(root);
2399 level = btrfs_header_level(b);
2400 if (level <= write_lock_level) {
2401 /* whoops, must trade for write lock */
2402 btrfs_tree_read_unlock(b);
2403 free_extent_buffer(b);
2404 b = btrfs_lock_root_node(root);
2405 root_lock = BTRFS_WRITE_LOCK;
2407 /* the level might have changed, check again */
2408 level = btrfs_header_level(b);
2412 p->nodes[level] = b;
2413 if (!p->skip_locking)
2414 p->locks[level] = root_lock;
2417 level = btrfs_header_level(b);
2420 * setup the path here so we can release it under lock
2421 * contention with the cow code
2425 * if we don't really need to cow this block
2426 * then we don't want to set the path blocking,
2427 * so we test it here
2429 if (!should_cow_block(trans, root, b))
2432 btrfs_set_path_blocking(p);
2435 * must have write locks on this node and the
2438 if (level + 1 > write_lock_level) {
2439 write_lock_level = level + 1;
2440 btrfs_release_path(p);
2444 err = btrfs_cow_block(trans, root, b,
2445 p->nodes[level + 1],
2446 p->slots[level + 1], &b);
2453 BUG_ON(!cow && ins_len);
2455 p->nodes[level] = b;
2456 btrfs_clear_path_blocking(p, NULL, 0);
2459 * we have a lock on b and as long as we aren't changing
2460 * the tree, there is no way to for the items in b to change.
2461 * It is safe to drop the lock on our parent before we
2462 * go through the expensive btree search on b.
2464 * If cow is true, then we might be changing slot zero,
2465 * which may require changing the parent. So, we can't
2466 * drop the lock until after we know which slot we're
2470 btrfs_unlock_up_safe(p, level + 1);
2472 ret = bin_search(b, key, level, &slot);
2476 if (ret && slot > 0) {
2480 p->slots[level] = slot;
2481 err = setup_nodes_for_search(trans, root, p, b, level,
2482 ins_len, &write_lock_level);
2489 b = p->nodes[level];
2490 slot = p->slots[level];
2493 * slot 0 is special, if we change the key
2494 * we have to update the parent pointer
2495 * which means we must have a write lock
2498 if (slot == 0 && cow &&
2499 write_lock_level < level + 1) {
2500 write_lock_level = level + 1;
2501 btrfs_release_path(p);
2505 unlock_up(p, level, lowest_unlock,
2506 min_write_lock_level, &write_lock_level);
2508 if (level == lowest_level) {
2514 err = read_block_for_search(trans, root, p,
2515 &b, level, slot, key, 0);
2523 if (!p->skip_locking) {
2524 level = btrfs_header_level(b);
2525 if (level <= write_lock_level) {
2526 err = btrfs_try_tree_write_lock(b);
2528 btrfs_set_path_blocking(p);
2530 btrfs_clear_path_blocking(p, b,
2533 p->locks[level] = BTRFS_WRITE_LOCK;
2535 err = btrfs_try_tree_read_lock(b);
2537 btrfs_set_path_blocking(p);
2538 btrfs_tree_read_lock(b);
2539 btrfs_clear_path_blocking(p, b,
2542 p->locks[level] = BTRFS_READ_LOCK;
2544 p->nodes[level] = b;
2547 p->slots[level] = slot;
2549 btrfs_leaf_free_space(root, b) < ins_len) {
2550 if (write_lock_level < 1) {
2551 write_lock_level = 1;
2552 btrfs_release_path(p);
2556 btrfs_set_path_blocking(p);
2557 err = split_leaf(trans, root, key,
2558 p, ins_len, ret == 0);
2559 btrfs_clear_path_blocking(p, NULL, 0);
2567 if (!p->search_for_split)
2568 unlock_up(p, level, lowest_unlock,
2569 min_write_lock_level, &write_lock_level);
2576 * we don't really know what they plan on doing with the path
2577 * from here on, so for now just mark it as blocking
2579 if (!p->leave_spinning)
2580 btrfs_set_path_blocking(p);
2582 btrfs_release_path(p);
2587 * Like btrfs_search_slot, this looks for a key in the given tree. It uses the
2588 * current state of the tree together with the operations recorded in the tree
2589 * modification log to search for the key in a previous version of this tree, as
2590 * denoted by the time_seq parameter.
2592 * Naturally, there is no support for insert, delete or cow operations.
2594 * The resulting path and return value will be set up as if we called
2595 * btrfs_search_slot at that point in time with ins_len and cow both set to 0.
2597 int btrfs_search_old_slot(struct btrfs_root *root, struct btrfs_key *key,
2598 struct btrfs_path *p, u64 time_seq)
2600 struct extent_buffer *b;
2605 int lowest_unlock = 1;
2606 u8 lowest_level = 0;
2608 lowest_level = p->lowest_level;
2609 WARN_ON(p->nodes[0] != NULL);
2611 if (p->search_commit_root) {
2613 return btrfs_search_slot(NULL, root, key, p, 0, 0);
2617 b = get_old_root(root, time_seq);
2618 extent_buffer_get(b);
2619 level = btrfs_header_level(b);
2620 btrfs_tree_read_lock(b);
2621 p->locks[level] = BTRFS_READ_LOCK;
2624 level = btrfs_header_level(b);
2625 p->nodes[level] = b;
2626 btrfs_clear_path_blocking(p, NULL, 0);
2629 * we have a lock on b and as long as we aren't changing
2630 * the tree, there is no way to for the items in b to change.
2631 * It is safe to drop the lock on our parent before we
2632 * go through the expensive btree search on b.
2634 btrfs_unlock_up_safe(p, level + 1);
2636 ret = bin_search(b, key, level, &slot);
2640 if (ret && slot > 0) {
2644 p->slots[level] = slot;
2645 unlock_up(p, level, lowest_unlock, 0, NULL);
2647 if (level == lowest_level) {
2653 err = read_block_for_search(NULL, root, p, &b, level,
2654 slot, key, time_seq);
2662 level = btrfs_header_level(b);
2663 err = btrfs_try_tree_read_lock(b);
2665 btrfs_set_path_blocking(p);
2666 btrfs_tree_read_lock(b);
2667 btrfs_clear_path_blocking(p, b,
2670 p->locks[level] = BTRFS_READ_LOCK;
2671 p->nodes[level] = b;
2672 b = tree_mod_log_rewind(root->fs_info, b, time_seq);
2673 if (b != p->nodes[level]) {
2674 btrfs_tree_unlock_rw(p->nodes[level],
2676 p->locks[level] = 0;
2677 p->nodes[level] = b;
2680 p->slots[level] = slot;
2681 unlock_up(p, level, lowest_unlock, 0, NULL);
2687 if (!p->leave_spinning)
2688 btrfs_set_path_blocking(p);
2690 btrfs_release_path(p);
2696 * adjust the pointers going up the tree, starting at level
2697 * making sure the right key of each node is points to 'key'.
2698 * This is used after shifting pointers to the left, so it stops
2699 * fixing up pointers when a given leaf/node is not in slot 0 of the
2703 static void fixup_low_keys(struct btrfs_trans_handle *trans,
2704 struct btrfs_root *root, struct btrfs_path *path,
2705 struct btrfs_disk_key *key, int level)
2708 struct extent_buffer *t;
2710 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
2711 int tslot = path->slots[i];
2712 if (!path->nodes[i])
2715 tree_mod_log_set_node_key(root->fs_info, t, key, tslot, 1);
2716 btrfs_set_node_key(t, key, tslot);
2717 btrfs_mark_buffer_dirty(path->nodes[i]);
2726 * This function isn't completely safe. It's the caller's responsibility
2727 * that the new key won't break the order
2729 void btrfs_set_item_key_safe(struct btrfs_trans_handle *trans,
2730 struct btrfs_root *root, struct btrfs_path *path,
2731 struct btrfs_key *new_key)
2733 struct btrfs_disk_key disk_key;
2734 struct extent_buffer *eb;
2737 eb = path->nodes[0];
2738 slot = path->slots[0];
2740 btrfs_item_key(eb, &disk_key, slot - 1);
2741 BUG_ON(comp_keys(&disk_key, new_key) >= 0);
2743 if (slot < btrfs_header_nritems(eb) - 1) {
2744 btrfs_item_key(eb, &disk_key, slot + 1);
2745 BUG_ON(comp_keys(&disk_key, new_key) <= 0);
2748 btrfs_cpu_key_to_disk(&disk_key, new_key);
2749 btrfs_set_item_key(eb, &disk_key, slot);
2750 btrfs_mark_buffer_dirty(eb);
2752 fixup_low_keys(trans, root, path, &disk_key, 1);
2756 * try to push data from one node into the next node left in the
2759 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
2760 * error, and > 0 if there was no room in the left hand block.
2762 static int push_node_left(struct btrfs_trans_handle *trans,
2763 struct btrfs_root *root, struct extent_buffer *dst,
2764 struct extent_buffer *src, int empty)
2771 src_nritems = btrfs_header_nritems(src);
2772 dst_nritems = btrfs_header_nritems(dst);
2773 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
2774 WARN_ON(btrfs_header_generation(src) != trans->transid);
2775 WARN_ON(btrfs_header_generation(dst) != trans->transid);
2777 if (!empty && src_nritems <= 8)
2780 if (push_items <= 0)
2784 push_items = min(src_nritems, push_items);
2785 if (push_items < src_nritems) {
2786 /* leave at least 8 pointers in the node if
2787 * we aren't going to empty it
2789 if (src_nritems - push_items < 8) {
2790 if (push_items <= 8)
2796 push_items = min(src_nritems - 8, push_items);
2798 tree_mod_log_eb_copy(root->fs_info, dst, src, dst_nritems, 0,
2800 copy_extent_buffer(dst, src,
2801 btrfs_node_key_ptr_offset(dst_nritems),
2802 btrfs_node_key_ptr_offset(0),
2803 push_items * sizeof(struct btrfs_key_ptr));
2805 if (push_items < src_nritems) {
2806 tree_mod_log_eb_move(root->fs_info, src, 0, push_items,
2807 src_nritems - push_items);
2808 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
2809 btrfs_node_key_ptr_offset(push_items),
2810 (src_nritems - push_items) *
2811 sizeof(struct btrfs_key_ptr));
2813 btrfs_set_header_nritems(src, src_nritems - push_items);
2814 btrfs_set_header_nritems(dst, dst_nritems + push_items);
2815 btrfs_mark_buffer_dirty(src);
2816 btrfs_mark_buffer_dirty(dst);
2822 * try to push data from one node into the next node right in the
2825 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
2826 * error, and > 0 if there was no room in the right hand block.
2828 * this will only push up to 1/2 the contents of the left node over
2830 static int balance_node_right(struct btrfs_trans_handle *trans,
2831 struct btrfs_root *root,
2832 struct extent_buffer *dst,
2833 struct extent_buffer *src)
2841 WARN_ON(btrfs_header_generation(src) != trans->transid);
2842 WARN_ON(btrfs_header_generation(dst) != trans->transid);
2844 src_nritems = btrfs_header_nritems(src);
2845 dst_nritems = btrfs_header_nritems(dst);
2846 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
2847 if (push_items <= 0)
2850 if (src_nritems < 4)
2853 max_push = src_nritems / 2 + 1;
2854 /* don't try to empty the node */
2855 if (max_push >= src_nritems)
2858 if (max_push < push_items)
2859 push_items = max_push;
2861 tree_mod_log_eb_move(root->fs_info, dst, push_items, 0, dst_nritems);
2862 memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
2863 btrfs_node_key_ptr_offset(0),
2865 sizeof(struct btrfs_key_ptr));
2867 tree_mod_log_eb_copy(root->fs_info, dst, src, 0,
2868 src_nritems - push_items, push_items);
2869 copy_extent_buffer(dst, src,
2870 btrfs_node_key_ptr_offset(0),
2871 btrfs_node_key_ptr_offset(src_nritems - push_items),
2872 push_items * sizeof(struct btrfs_key_ptr));
2874 btrfs_set_header_nritems(src, src_nritems - push_items);
2875 btrfs_set_header_nritems(dst, dst_nritems + push_items);
2877 btrfs_mark_buffer_dirty(src);
2878 btrfs_mark_buffer_dirty(dst);
2884 * helper function to insert a new root level in the tree.
2885 * A new node is allocated, and a single item is inserted to
2886 * point to the existing root
2888 * returns zero on success or < 0 on failure.
2890 static noinline int insert_new_root(struct btrfs_trans_handle *trans,
2891 struct btrfs_root *root,
2892 struct btrfs_path *path, int level)
2895 struct extent_buffer *lower;
2896 struct extent_buffer *c;
2897 struct extent_buffer *old;
2898 struct btrfs_disk_key lower_key;
2900 BUG_ON(path->nodes[level]);
2901 BUG_ON(path->nodes[level-1] != root->node);
2903 lower = path->nodes[level-1];
2905 btrfs_item_key(lower, &lower_key, 0);
2907 btrfs_node_key(lower, &lower_key, 0);
2909 c = btrfs_alloc_free_block(trans, root, root->nodesize, 0,
2910 root->root_key.objectid, &lower_key,
2911 level, root->node->start, 0);
2915 root_add_used(root, root->nodesize);
2917 memset_extent_buffer(c, 0, 0, sizeof(struct btrfs_header));
2918 btrfs_set_header_nritems(c, 1);
2919 btrfs_set_header_level(c, level);
2920 btrfs_set_header_bytenr(c, c->start);
2921 btrfs_set_header_generation(c, trans->transid);
2922 btrfs_set_header_backref_rev(c, BTRFS_MIXED_BACKREF_REV);
2923 btrfs_set_header_owner(c, root->root_key.objectid);
2925 write_extent_buffer(c, root->fs_info->fsid,
2926 (unsigned long)btrfs_header_fsid(c),
2929 write_extent_buffer(c, root->fs_info->chunk_tree_uuid,
2930 (unsigned long)btrfs_header_chunk_tree_uuid(c),
2933 btrfs_set_node_key(c, &lower_key, 0);
2934 btrfs_set_node_blockptr(c, 0, lower->start);
2935 lower_gen = btrfs_header_generation(lower);
2936 WARN_ON(lower_gen != trans->transid);
2938 btrfs_set_node_ptr_generation(c, 0, lower_gen);
2940 btrfs_mark_buffer_dirty(c);
2943 tree_mod_log_set_root_pointer(root, c);
2944 rcu_assign_pointer(root->node, c);
2946 /* the super has an extra ref to root->node */
2947 free_extent_buffer(old);
2949 add_root_to_dirty_list(root);
2950 extent_buffer_get(c);
2951 path->nodes[level] = c;
2952 path->locks[level] = BTRFS_WRITE_LOCK;
2953 path->slots[level] = 0;
2958 * worker function to insert a single pointer in a node.
2959 * the node should have enough room for the pointer already
2961 * slot and level indicate where you want the key to go, and
2962 * blocknr is the block the key points to.
2964 static void insert_ptr(struct btrfs_trans_handle *trans,
2965 struct btrfs_root *root, struct btrfs_path *path,
2966 struct btrfs_disk_key *key, u64 bytenr,
2967 int slot, int level, int tree_mod_log)
2969 struct extent_buffer *lower;
2973 BUG_ON(!path->nodes[level]);
2974 btrfs_assert_tree_locked(path->nodes[level]);
2975 lower = path->nodes[level];
2976 nritems = btrfs_header_nritems(lower);
2977 BUG_ON(slot > nritems);
2978 BUG_ON(nritems == BTRFS_NODEPTRS_PER_BLOCK(root));
2979 if (slot != nritems) {
2980 if (tree_mod_log && level)
2981 tree_mod_log_eb_move(root->fs_info, lower, slot + 1,
2982 slot, nritems - slot);
2983 memmove_extent_buffer(lower,
2984 btrfs_node_key_ptr_offset(slot + 1),
2985 btrfs_node_key_ptr_offset(slot),
2986 (nritems - slot) * sizeof(struct btrfs_key_ptr));
2988 if (tree_mod_log && level) {
2989 ret = tree_mod_log_insert_key(root->fs_info, lower, slot,
2993 btrfs_set_node_key(lower, key, slot);
2994 btrfs_set_node_blockptr(lower, slot, bytenr);
2995 WARN_ON(trans->transid == 0);
2996 btrfs_set_node_ptr_generation(lower, slot, trans->transid);
2997 btrfs_set_header_nritems(lower, nritems + 1);
2998 btrfs_mark_buffer_dirty(lower);
3002 * split the node at the specified level in path in two.
3003 * The path is corrected to point to the appropriate node after the split
3005 * Before splitting this tries to make some room in the node by pushing
3006 * left and right, if either one works, it returns right away.
3008 * returns 0 on success and < 0 on failure
3010 static noinline int split_node(struct btrfs_trans_handle *trans,
3011 struct btrfs_root *root,
3012 struct btrfs_path *path, int level)
3014 struct extent_buffer *c;
3015 struct extent_buffer *split;
3016 struct btrfs_disk_key disk_key;
3021 c = path->nodes[level];
3022 WARN_ON(btrfs_header_generation(c) != trans->transid);
3023 if (c == root->node) {
3024 /* trying to split the root, lets make a new one */
3025 ret = insert_new_root(trans, root, path, level + 1);
3029 ret = push_nodes_for_insert(trans, root, path, level);
3030 c = path->nodes[level];
3031 if (!ret && btrfs_header_nritems(c) <
3032 BTRFS_NODEPTRS_PER_BLOCK(root) - 3)
3038 c_nritems = btrfs_header_nritems(c);
3039 mid = (c_nritems + 1) / 2;
3040 btrfs_node_key(c, &disk_key, mid);
3042 split = btrfs_alloc_free_block(trans, root, root->nodesize, 0,
3043 root->root_key.objectid,
3044 &disk_key, level, c->start, 0);
3046 return PTR_ERR(split);
3048 root_add_used(root, root->nodesize);
3050 memset_extent_buffer(split, 0, 0, sizeof(struct btrfs_header));
3051 btrfs_set_header_level(split, btrfs_header_level(c));
3052 btrfs_set_header_bytenr(split, split->start);
3053 btrfs_set_header_generation(split, trans->transid);
3054 btrfs_set_header_backref_rev(split, BTRFS_MIXED_BACKREF_REV);
3055 btrfs_set_header_owner(split, root->root_key.objectid);
3056 write_extent_buffer(split, root->fs_info->fsid,
3057 (unsigned long)btrfs_header_fsid(split),
3059 write_extent_buffer(split, root->fs_info->chunk_tree_uuid,
3060 (unsigned long)btrfs_header_chunk_tree_uuid(split),
3063 tree_mod_log_eb_copy(root->fs_info, split, c, 0, mid, c_nritems - mid);
3064 copy_extent_buffer(split, c,
3065 btrfs_node_key_ptr_offset(0),
3066 btrfs_node_key_ptr_offset(mid),
3067 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
3068 btrfs_set_header_nritems(split, c_nritems - mid);
3069 btrfs_set_header_nritems(c, mid);
3072 btrfs_mark_buffer_dirty(c);
3073 btrfs_mark_buffer_dirty(split);
3075 insert_ptr(trans, root, path, &disk_key, split->start,
3076 path->slots[level + 1] + 1, level + 1, 1);
3078 if (path->slots[level] >= mid) {
3079 path->slots[level] -= mid;
3080 btrfs_tree_unlock(c);
3081 free_extent_buffer(c);
3082 path->nodes[level] = split;
3083 path->slots[level + 1] += 1;
3085 btrfs_tree_unlock(split);
3086 free_extent_buffer(split);
3092 * how many bytes are required to store the items in a leaf. start
3093 * and nr indicate which items in the leaf to check. This totals up the
3094 * space used both by the item structs and the item data
3096 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
3099 int nritems = btrfs_header_nritems(l);
3100 int end = min(nritems, start + nr) - 1;
3104 data_len = btrfs_item_end_nr(l, start);
3105 data_len = data_len - btrfs_item_offset_nr(l, end);
3106 data_len += sizeof(struct btrfs_item) * nr;
3107 WARN_ON(data_len < 0);
3112 * The space between the end of the leaf items and
3113 * the start of the leaf data. IOW, how much room
3114 * the leaf has left for both items and data
3116 noinline int btrfs_leaf_free_space(struct btrfs_root *root,
3117 struct extent_buffer *leaf)
3119 int nritems = btrfs_header_nritems(leaf);
3121 ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
3123 printk(KERN_CRIT "leaf free space ret %d, leaf data size %lu, "
3124 "used %d nritems %d\n",
3125 ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
3126 leaf_space_used(leaf, 0, nritems), nritems);
3132 * min slot controls the lowest index we're willing to push to the
3133 * right. We'll push up to and including min_slot, but no lower
3135 static noinline int __push_leaf_right(struct btrfs_trans_handle *trans,
3136 struct btrfs_root *root,
3137 struct btrfs_path *path,
3138 int data_size, int empty,
3139 struct extent_buffer *right,
3140 int free_space, u32 left_nritems,
3143 struct extent_buffer *left = path->nodes[0];
3144 struct extent_buffer *upper = path->nodes[1];
3145 struct btrfs_map_token token;
3146 struct btrfs_disk_key disk_key;
3151 struct btrfs_item *item;
3157 btrfs_init_map_token(&token);
3162 nr = max_t(u32, 1, min_slot);
3164 if (path->slots[0] >= left_nritems)
3165 push_space += data_size;
3167 slot = path->slots[1];
3168 i = left_nritems - 1;
3170 item = btrfs_item_nr(left, i);
3172 if (!empty && push_items > 0) {
3173 if (path->slots[0] > i)
3175 if (path->slots[0] == i) {
3176 int space = btrfs_leaf_free_space(root, left);
3177 if (space + push_space * 2 > free_space)
3182 if (path->slots[0] == i)
3183 push_space += data_size;
3185 this_item_size = btrfs_item_size(left, item);
3186 if (this_item_size + sizeof(*item) + push_space > free_space)
3190 push_space += this_item_size + sizeof(*item);
3196 if (push_items == 0)
3199 if (!empty && push_items == left_nritems)
3202 /* push left to right */
3203 right_nritems = btrfs_header_nritems(right);
3205 push_space = btrfs_item_end_nr(left, left_nritems - push_items);
3206 push_space -= leaf_data_end(root, left);
3208 /* make room in the right data area */
3209 data_end = leaf_data_end(root, right);
3210 memmove_extent_buffer(right,
3211 btrfs_leaf_data(right) + data_end - push_space,
3212 btrfs_leaf_data(right) + data_end,
3213 BTRFS_LEAF_DATA_SIZE(root) - data_end);
3215 /* copy from the left data area */
3216 copy_extent_buffer(right, left, btrfs_leaf_data(right) +
3217 BTRFS_LEAF_DATA_SIZE(root) - push_space,
3218 btrfs_leaf_data(left) + leaf_data_end(root, left),
3221 memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
3222 btrfs_item_nr_offset(0),
3223 right_nritems * sizeof(struct btrfs_item));
3225 /* copy the items from left to right */
3226 copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
3227 btrfs_item_nr_offset(left_nritems - push_items),
3228 push_items * sizeof(struct btrfs_item));
3230 /* update the item pointers */
3231 right_nritems += push_items;
3232 btrfs_set_header_nritems(right, right_nritems);
3233 push_space = BTRFS_LEAF_DATA_SIZE(root);
3234 for (i = 0; i < right_nritems; i++) {
3235 item = btrfs_item_nr(right, i);
3236 push_space -= btrfs_token_item_size(right, item, &token);
3237 btrfs_set_token_item_offset(right, item, push_space, &token);
3240 left_nritems -= push_items;
3241 btrfs_set_header_nritems(left, left_nritems);
3244 btrfs_mark_buffer_dirty(left);
3246 clean_tree_block(trans, root, left);
3248 btrfs_mark_buffer_dirty(right);
3250 btrfs_item_key(right, &disk_key, 0);
3251 btrfs_set_node_key(upper, &disk_key, slot + 1);
3252 btrfs_mark_buffer_dirty(upper);
3254 /* then fixup the leaf pointer in the path */
3255 if (path->slots[0] >= left_nritems) {
3256 path->slots[0] -= left_nritems;
3257 if (btrfs_header_nritems(path->nodes[0]) == 0)
3258 clean_tree_block(trans, root, path->nodes[0]);
3259 btrfs_tree_unlock(path->nodes[0]);
3260 free_extent_buffer(path->nodes[0]);
3261 path->nodes[0] = right;
3262 path->slots[1] += 1;
3264 btrfs_tree_unlock(right);
3265 free_extent_buffer(right);
3270 btrfs_tree_unlock(right);
3271 free_extent_buffer(right);
3276 * push some data in the path leaf to the right, trying to free up at
3277 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3279 * returns 1 if the push failed because the other node didn't have enough
3280 * room, 0 if everything worked out and < 0 if there were major errors.
3282 * this will push starting from min_slot to the end of the leaf. It won't
3283 * push any slot lower than min_slot
3285 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
3286 *root, struct btrfs_path *path,
3287 int min_data_size, int data_size,
3288 int empty, u32 min_slot)
3290 struct extent_buffer *left = path->nodes[0];
3291 struct extent_buffer *right;
3292 struct extent_buffer *upper;
3298 if (!path->nodes[1])
3301 slot = path->slots[1];
3302 upper = path->nodes[1];
3303 if (slot >= btrfs_header_nritems(upper) - 1)
3306 btrfs_assert_tree_locked(path->nodes[1]);
3308 right = read_node_slot(root, upper, slot + 1);
3312 btrfs_tree_lock(right);
3313 btrfs_set_lock_blocking(right);
3315 free_space = btrfs_leaf_free_space(root, right);
3316 if (free_space < data_size)
3319 /* cow and double check */
3320 ret = btrfs_cow_block(trans, root, right, upper,
3325 free_space = btrfs_leaf_free_space(root, right);
3326 if (free_space < data_size)
3329 left_nritems = btrfs_header_nritems(left);
3330 if (left_nritems == 0)
3333 return __push_leaf_right(trans, root, path, min_data_size, empty,
3334 right, free_space, left_nritems, min_slot);
3336 btrfs_tree_unlock(right);
3337 free_extent_buffer(right);
3342 * push some data in the path leaf to the left, trying to free up at
3343 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3345 * max_slot can put a limit on how far into the leaf we'll push items. The
3346 * item at 'max_slot' won't be touched. Use (u32)-1 to make us do all the
3349 static noinline int __push_leaf_left(struct btrfs_trans_handle *trans,
3350 struct btrfs_root *root,
3351 struct btrfs_path *path, int data_size,
3352 int empty, struct extent_buffer *left,
3353 int free_space, u32 right_nritems,
3356 struct btrfs_disk_key disk_key;
3357 struct extent_buffer *right = path->nodes[0];
3361 struct btrfs_item *item;
3362 u32 old_left_nritems;
3366 u32 old_left_item_size;
3367 struct btrfs_map_token token;
3369 btrfs_init_map_token(&token);
3372 nr = min(right_nritems, max_slot);
3374 nr = min(right_nritems - 1, max_slot);
3376 for (i = 0; i < nr; i++) {
3377 item = btrfs_item_nr(right, i);
3379 if (!empty && push_items > 0) {
3380 if (path->slots[0] < i)
3382 if (path->slots[0] == i) {
3383 int space = btrfs_leaf_free_space(root, right);
3384 if (space + push_space * 2 > free_space)
3389 if (path->slots[0] == i)
3390 push_space += data_size;
3392 this_item_size = btrfs_item_size(right, item);
3393 if (this_item_size + sizeof(*item) + push_space > free_space)
3397 push_space += this_item_size + sizeof(*item);
3400 if (push_items == 0) {
3404 if (!empty && push_items == btrfs_header_nritems(right))
3407 /* push data from right to left */
3408 copy_extent_buffer(left, right,
3409 btrfs_item_nr_offset(btrfs_header_nritems(left)),
3410 btrfs_item_nr_offset(0),
3411 push_items * sizeof(struct btrfs_item));
3413 push_space = BTRFS_LEAF_DATA_SIZE(root) -
3414 btrfs_item_offset_nr(right, push_items - 1);
3416 copy_extent_buffer(left, right, btrfs_leaf_data(left) +
3417 leaf_data_end(root, left) - push_space,
3418 btrfs_leaf_data(right) +
3419 btrfs_item_offset_nr(right, push_items - 1),
3421 old_left_nritems = btrfs_header_nritems(left);
3422 BUG_ON(old_left_nritems <= 0);
3424 old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
3425 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
3428 item = btrfs_item_nr(left, i);
3430 ioff = btrfs_token_item_offset(left, item, &token);
3431 btrfs_set_token_item_offset(left, item,
3432 ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size),
3435 btrfs_set_header_nritems(left, old_left_nritems + push_items);
3437 /* fixup right node */
3438 if (push_items > right_nritems) {
3439 printk(KERN_CRIT "push items %d nr %u\n", push_items,
3444 if (push_items < right_nritems) {
3445 push_space = btrfs_item_offset_nr(right, push_items - 1) -
3446 leaf_data_end(root, right);
3447 memmove_extent_buffer(right, btrfs_leaf_data(right) +
3448 BTRFS_LEAF_DATA_SIZE(root) - push_space,
3449 btrfs_leaf_data(right) +
3450 leaf_data_end(root, right), push_space);
3452 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
3453 btrfs_item_nr_offset(push_items),
3454 (btrfs_header_nritems(right) - push_items) *
3455 sizeof(struct btrfs_item));
3457 right_nritems -= push_items;
3458 btrfs_set_header_nritems(right, right_nritems);
3459 push_space = BTRFS_LEAF_DATA_SIZE(root);
3460 for (i = 0; i < right_nritems; i++) {
3461 item = btrfs_item_nr(right, i);
3463 push_space = push_space - btrfs_token_item_size(right,
3465 btrfs_set_token_item_offset(right, item, push_space, &token);
3468 btrfs_mark_buffer_dirty(left);
3470 btrfs_mark_buffer_dirty(right);
3472 clean_tree_block(trans, root, right);
3474 btrfs_item_key(right, &disk_key, 0);
3475 fixup_low_keys(trans, root, path, &disk_key, 1);
3477 /* then fixup the leaf pointer in the path */
3478 if (path->slots[0] < push_items) {
3479 path->slots[0] += old_left_nritems;
3480 btrfs_tree_unlock(path->nodes[0]);
3481 free_extent_buffer(path->nodes[0]);
3482 path->nodes[0] = left;
3483 path->slots[1] -= 1;
3485 btrfs_tree_unlock(left);
3486 free_extent_buffer(left);
3487 path->slots[0] -= push_items;
3489 BUG_ON(path->slots[0] < 0);
3492 btrfs_tree_unlock(left);
3493 free_extent_buffer(left);
3498 * push some data in the path leaf to the left, trying to free up at
3499 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3501 * max_slot can put a limit on how far into the leaf we'll push items. The
3502 * item at 'max_slot' won't be touched. Use (u32)-1 to make us push all the
3505 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
3506 *root, struct btrfs_path *path, int min_data_size,
3507 int data_size, int empty, u32 max_slot)
3509 struct extent_buffer *right = path->nodes[0];
3510 struct extent_buffer *left;
3516 slot = path->slots[1];
3519 if (!path->nodes[1])
3522 right_nritems = btrfs_header_nritems(right);
3523 if (right_nritems == 0)
3526 btrfs_assert_tree_locked(path->nodes[1]);
3528 left = read_node_slot(root, path->nodes[1], slot - 1);
3532 btrfs_tree_lock(left);
3533 btrfs_set_lock_blocking(left);
3535 free_space = btrfs_leaf_free_space(root, left);
3536 if (free_space < data_size) {
3541 /* cow and double check */
3542 ret = btrfs_cow_block(trans, root, left,
3543 path->nodes[1], slot - 1, &left);
3545 /* we hit -ENOSPC, but it isn't fatal here */
3551 free_space = btrfs_leaf_free_space(root, left);
3552 if (free_space < data_size) {
3557 return __push_leaf_left(trans, root, path, min_data_size,
3558 empty, left, free_space, right_nritems,
3561 btrfs_tree_unlock(left);
3562 free_extent_buffer(left);
3567 * split the path's leaf in two, making sure there is at least data_size
3568 * available for the resulting leaf level of the path.
3570 static noinline void copy_for_split(struct btrfs_trans_handle *trans,
3571 struct btrfs_root *root,
3572 struct btrfs_path *path,
3573 struct extent_buffer *l,
3574 struct extent_buffer *right,
3575 int slot, int mid, int nritems)
3580 struct btrfs_disk_key disk_key;
3581 struct btrfs_map_token token;
3583 btrfs_init_map_token(&token);
3585 nritems = nritems - mid;
3586 btrfs_set_header_nritems(right, nritems);
3587 data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
3589 copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
3590 btrfs_item_nr_offset(mid),
3591 nritems * sizeof(struct btrfs_item));
3593 copy_extent_buffer(right, l,
3594 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
3595 data_copy_size, btrfs_leaf_data(l) +
3596 leaf_data_end(root, l), data_copy_size);
3598 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
3599 btrfs_item_end_nr(l, mid);
3601 for (i = 0; i < nritems; i++) {
3602 struct btrfs_item *item = btrfs_item_nr(right, i);
3605 ioff = btrfs_token_item_offset(right, item, &token);
3606 btrfs_set_token_item_offset(right, item,
3607 ioff + rt_data_off, &token);
3610 btrfs_set_header_nritems(l, mid);
3611 btrfs_item_key(right, &disk_key, 0);
3612 insert_ptr(trans, root, path, &disk_key, right->start,
3613 path->slots[1] + 1, 1, 0);
3615 btrfs_mark_buffer_dirty(right);
3616 btrfs_mark_buffer_dirty(l);
3617 BUG_ON(path->slots[0] != slot);
3620 btrfs_tree_unlock(path->nodes[0]);
3621 free_extent_buffer(path->nodes[0]);
3622 path->nodes[0] = right;
3623 path->slots[0] -= mid;
3624 path->slots[1] += 1;
3626 btrfs_tree_unlock(right);
3627 free_extent_buffer(right);
3630 BUG_ON(path->slots[0] < 0);
3634 * double splits happen when we need to insert a big item in the middle
3635 * of a leaf. A double split can leave us with 3 mostly empty leaves:
3636 * leaf: [ slots 0 - N] [ our target ] [ N + 1 - total in leaf ]
3639 * We avoid this by trying to push the items on either side of our target
3640 * into the adjacent leaves. If all goes well we can avoid the double split
3643 static noinline int push_for_double_split(struct btrfs_trans_handle *trans,
3644 struct btrfs_root *root,
3645 struct btrfs_path *path,
3653 slot = path->slots[0];
3656 * try to push all the items after our slot into the
3659 ret = push_leaf_right(trans, root, path, 1, data_size, 0, slot);
3666 nritems = btrfs_header_nritems(path->nodes[0]);
3668 * our goal is to get our slot at the start or end of a leaf. If
3669 * we've done so we're done
3671 if (path->slots[0] == 0 || path->slots[0] == nritems)
3674 if (btrfs_leaf_free_space(root, path->nodes[0]) >= data_size)
3677 /* try to push all the items before our slot into the next leaf */
3678 slot = path->slots[0];
3679 ret = push_leaf_left(trans, root, path, 1, data_size, 0, slot);
3692 * split the path's leaf in two, making sure there is at least data_size
3693 * available for the resulting leaf level of the path.
3695 * returns 0 if all went well and < 0 on failure.
3697 static noinline int split_leaf(struct btrfs_trans_handle *trans,
3698 struct btrfs_root *root,
3699 struct btrfs_key *ins_key,
3700 struct btrfs_path *path, int data_size,
3703 struct btrfs_disk_key disk_key;
3704 struct extent_buffer *l;
3708 struct extent_buffer *right;
3712 int num_doubles = 0;
3713 int tried_avoid_double = 0;
3716 slot = path->slots[0];
3717 if (extend && data_size + btrfs_item_size_nr(l, slot) +
3718 sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(root))
3721 /* first try to make some room by pushing left and right */
3723 wret = push_leaf_right(trans, root, path, data_size,
3728 wret = push_leaf_left(trans, root, path, data_size,
3729 data_size, 0, (u32)-1);
3735 /* did the pushes work? */
3736 if (btrfs_leaf_free_space(root, l) >= data_size)
3740 if (!path->nodes[1]) {
3741 ret = insert_new_root(trans, root, path, 1);
3748 slot = path->slots[0];
3749 nritems = btrfs_header_nritems(l);
3750 mid = (nritems + 1) / 2;
3754 leaf_space_used(l, mid, nritems - mid) + data_size >
3755 BTRFS_LEAF_DATA_SIZE(root)) {
3756 if (slot >= nritems) {
3760 if (mid != nritems &&
3761 leaf_space_used(l, mid, nritems - mid) +
3762 data_size > BTRFS_LEAF_DATA_SIZE(root)) {
3763 if (data_size && !tried_avoid_double)
3764 goto push_for_double;
3770 if (leaf_space_used(l, 0, mid) + data_size >
3771 BTRFS_LEAF_DATA_SIZE(root)) {
3772 if (!extend && data_size && slot == 0) {
3774 } else if ((extend || !data_size) && slot == 0) {
3778 if (mid != nritems &&
3779 leaf_space_used(l, mid, nritems - mid) +
3780 data_size > BTRFS_LEAF_DATA_SIZE(root)) {
3781 if (data_size && !tried_avoid_double)
3782 goto push_for_double;
3790 btrfs_cpu_key_to_disk(&disk_key, ins_key);
3792 btrfs_item_key(l, &disk_key, mid);
3794 right = btrfs_alloc_free_block(trans, root, root->leafsize, 0,
3795 root->root_key.objectid,
3796 &disk_key, 0, l->start, 0);
3798 return PTR_ERR(right);
3800 root_add_used(root, root->leafsize);
3802 memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
3803 btrfs_set_header_bytenr(right, right->start);
3804 btrfs_set_header_generation(right, trans->transid);
3805 btrfs_set_header_backref_rev(right, BTRFS_MIXED_BACKREF_REV);
3806 btrfs_set_header_owner(right, root->root_key.objectid);
3807 btrfs_set_header_level(right, 0);
3808 write_extent_buffer(right, root->fs_info->fsid,
3809 (unsigned long)btrfs_header_fsid(right),
3812 write_extent_buffer(right, root->fs_info->chunk_tree_uuid,
3813 (unsigned long)btrfs_header_chunk_tree_uuid(right),
3818 btrfs_set_header_nritems(right, 0);
3819 insert_ptr(trans, root, path, &disk_key, right->start,
3820 path->slots[1] + 1, 1, 0);
3821 btrfs_tree_unlock(path->nodes[0]);
3822 free_extent_buffer(path->nodes[0]);
3823 path->nodes[0] = right;
3825 path->slots[1] += 1;
3827 btrfs_set_header_nritems(right, 0);
3828 insert_ptr(trans, root, path, &disk_key, right->start,
3829 path->slots[1], 1, 0);
3830 btrfs_tree_unlock(path->nodes[0]);
3831 free_extent_buffer(path->nodes[0]);
3832 path->nodes[0] = right;
3834 if (path->slots[1] == 0)
3835 fixup_low_keys(trans, root, path,
3838 btrfs_mark_buffer_dirty(right);
3842 copy_for_split(trans, root, path, l, right, slot, mid, nritems);
3845 BUG_ON(num_doubles != 0);
3853 push_for_double_split(trans, root, path, data_size);
3854 tried_avoid_double = 1;
3855 if (btrfs_leaf_free_space(root, path->nodes[0]) >= data_size)
3860 static noinline int setup_leaf_for_split(struct btrfs_trans_handle *trans,
3861 struct btrfs_root *root,
3862 struct btrfs_path *path, int ins_len)
3864 struct btrfs_key key;
3865 struct extent_buffer *leaf;
3866 struct btrfs_file_extent_item *fi;
3871 leaf = path->nodes[0];
3872 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3874 BUG_ON(key.type != BTRFS_EXTENT_DATA_KEY &&
3875 key.type != BTRFS_EXTENT_CSUM_KEY);
3877 if (btrfs_leaf_free_space(root, leaf) >= ins_len)
3880 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
3881 if (key.type == BTRFS_EXTENT_DATA_KEY) {
3882 fi = btrfs_item_ptr(leaf, path->slots[0],
3883 struct btrfs_file_extent_item);
3884 extent_len = btrfs_file_extent_num_bytes(leaf, fi);
3886 btrfs_release_path(path);
3888 path->keep_locks = 1;
3889 path->search_for_split = 1;
3890 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
3891 path->search_for_split = 0;
3896 leaf = path->nodes[0];
3897 /* if our item isn't there or got smaller, return now */
3898 if (ret > 0 || item_size != btrfs_item_size_nr(leaf, path->slots[0]))
3901 /* the leaf has changed, it now has room. return now */
3902 if (btrfs_leaf_free_space(root, path->nodes[0]) >= ins_len)
3905 if (key.type == BTRFS_EXTENT_DATA_KEY) {
3906 fi = btrfs_item_ptr(leaf, path->slots[0],
3907 struct btrfs_file_extent_item);
3908 if (extent_len != btrfs_file_extent_num_bytes(leaf, fi))
3912 btrfs_set_path_blocking(path);
3913 ret = split_leaf(trans, root, &key, path, ins_len, 1);
3917 path->keep_locks = 0;
3918 btrfs_unlock_up_safe(path, 1);
3921 path->keep_locks = 0;
3925 static noinline int split_item(struct btrfs_trans_handle *trans,
3926 struct btrfs_root *root,
3927 struct btrfs_path *path,
3928 struct btrfs_key *new_key,
3929 unsigned long split_offset)
3931 struct extent_buffer *leaf;
3932 struct btrfs_item *item;
3933 struct btrfs_item *new_item;
3939 struct btrfs_disk_key disk_key;
3941 leaf = path->nodes[0];
3942 BUG_ON(btrfs_leaf_free_space(root, leaf) < sizeof(struct btrfs_item));
3944 btrfs_set_path_blocking(path);
3946 item = btrfs_item_nr(leaf, path->slots[0]);
3947 orig_offset = btrfs_item_offset(leaf, item);
3948 item_size = btrfs_item_size(leaf, item);
3950 buf = kmalloc(item_size, GFP_NOFS);
3954 read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf,
3955 path->slots[0]), item_size);
3957 slot = path->slots[0] + 1;
3958 nritems = btrfs_header_nritems(leaf);
3959 if (slot != nritems) {
3960 /* shift the items */
3961 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1),
3962 btrfs_item_nr_offset(slot),
3963 (nritems - slot) * sizeof(struct btrfs_item));
3966 btrfs_cpu_key_to_disk(&disk_key, new_key);
3967 btrfs_set_item_key(leaf, &disk_key, slot);
3969 new_item = btrfs_item_nr(leaf, slot);
3971 btrfs_set_item_offset(leaf, new_item, orig_offset);
3972 btrfs_set_item_size(leaf, new_item, item_size - split_offset);
3974 btrfs_set_item_offset(leaf, item,
3975 orig_offset + item_size - split_offset);
3976 btrfs_set_item_size(leaf, item, split_offset);
3978 btrfs_set_header_nritems(leaf, nritems + 1);
3980 /* write the data for the start of the original item */
3981 write_extent_buffer(leaf, buf,
3982 btrfs_item_ptr_offset(leaf, path->slots[0]),
3985 /* write the data for the new item */
3986 write_extent_buffer(leaf, buf + split_offset,
3987 btrfs_item_ptr_offset(leaf, slot),
3988 item_size - split_offset);
3989 btrfs_mark_buffer_dirty(leaf);
3991 BUG_ON(btrfs_leaf_free_space(root, leaf) < 0);
3997 * This function splits a single item into two items,
3998 * giving 'new_key' to the new item and splitting the
3999 * old one at split_offset (from the start of the item).
4001 * The path may be released by this operation. After
4002 * the split, the path is pointing to the old item. The
4003 * new item is going to be in the same node as the old one.
4005 * Note, the item being split must be smaller enough to live alone on
4006 * a tree block with room for one extra struct btrfs_item
4008 * This allows us to split the item in place, keeping a lock on the
4009 * leaf the entire time.
4011 int btrfs_split_item(struct btrfs_trans_handle *trans,
4012 struct btrfs_root *root,
4013 struct btrfs_path *path,
4014 struct btrfs_key *new_key,
4015 unsigned long split_offset)
4018 ret = setup_leaf_for_split(trans, root, path,
4019 sizeof(struct btrfs_item));
4023 ret = split_item(trans, root, path, new_key, split_offset);
4028 * This function duplicate a item, giving 'new_key' to the new item.
4029 * It guarantees both items live in the same tree leaf and the new item
4030 * is contiguous with the original item.
4032 * This allows us to split file extent in place, keeping a lock on the
4033 * leaf the entire time.
4035 int btrfs_duplicate_item(struct btrfs_trans_handle *trans,
4036 struct btrfs_root *root,
4037 struct btrfs_path *path,
4038 struct btrfs_key *new_key)
4040 struct extent_buffer *leaf;
4044 leaf = path->nodes[0];
4045 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
4046 ret = setup_leaf_for_split(trans, root, path,
4047 item_size + sizeof(struct btrfs_item));
4052 setup_items_for_insert(trans, root, path, new_key, &item_size,
4053 item_size, item_size +
4054 sizeof(struct btrfs_item), 1);
4055 leaf = path->nodes[0];
4056 memcpy_extent_buffer(leaf,
4057 btrfs_item_ptr_offset(leaf, path->slots[0]),
4058 btrfs_item_ptr_offset(leaf, path->slots[0] - 1),
4064 * make the item pointed to by the path smaller. new_size indicates
4065 * how small to make it, and from_end tells us if we just chop bytes
4066 * off the end of the item or if we shift the item to chop bytes off
4069 void btrfs_truncate_item(struct btrfs_trans_handle *trans,
4070 struct btrfs_root *root,
4071 struct btrfs_path *path,
4072 u32 new_size, int from_end)
4075 struct extent_buffer *leaf;
4076 struct btrfs_item *item;
4078 unsigned int data_end;
4079 unsigned int old_data_start;
4080 unsigned int old_size;
4081 unsigned int size_diff;
4083 struct btrfs_map_token token;
4085 btrfs_init_map_token(&token);
4087 leaf = path->nodes[0];
4088 slot = path->slots[0];
4090 old_size = btrfs_item_size_nr(leaf, slot);
4091 if (old_size == new_size)
4094 nritems = btrfs_header_nritems(leaf);
4095 data_end = leaf_data_end(root, leaf);
4097 old_data_start = btrfs_item_offset_nr(leaf, slot);
4099 size_diff = old_size - new_size;
4102 BUG_ON(slot >= nritems);
4105 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4107 /* first correct the data pointers */
4108 for (i = slot; i < nritems; i++) {
4110 item = btrfs_item_nr(leaf, i);
4112 ioff = btrfs_token_item_offset(leaf, item, &token);
4113 btrfs_set_token_item_offset(leaf, item,
4114 ioff + size_diff, &token);
4117 /* shift the data */
4119 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
4120 data_end + size_diff, btrfs_leaf_data(leaf) +
4121 data_end, old_data_start + new_size - data_end);
4123 struct btrfs_disk_key disk_key;
4126 btrfs_item_key(leaf, &disk_key, slot);
4128 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
4130 struct btrfs_file_extent_item *fi;
4132 fi = btrfs_item_ptr(leaf, slot,
4133 struct btrfs_file_extent_item);
4134 fi = (struct btrfs_file_extent_item *)(
4135 (unsigned long)fi - size_diff);
4137 if (btrfs_file_extent_type(leaf, fi) ==
4138 BTRFS_FILE_EXTENT_INLINE) {
4139 ptr = btrfs_item_ptr_offset(leaf, slot);
4140 memmove_extent_buffer(leaf, ptr,
4142 offsetof(struct btrfs_file_extent_item,
4147 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
4148 data_end + size_diff, btrfs_leaf_data(leaf) +
4149 data_end, old_data_start - data_end);
4151 offset = btrfs_disk_key_offset(&disk_key);
4152 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
4153 btrfs_set_item_key(leaf, &disk_key, slot);
4155 fixup_low_keys(trans, root, path, &disk_key, 1);
4158 item = btrfs_item_nr(leaf, slot);
4159 btrfs_set_item_size(leaf, item, new_size);
4160 btrfs_mark_buffer_dirty(leaf);
4162 if (btrfs_leaf_free_space(root, leaf) < 0) {
4163 btrfs_print_leaf(root, leaf);
4169 * make the item pointed to by the path bigger, data_size is the new size.
4171 void btrfs_extend_item(struct btrfs_trans_handle *trans,
4172 struct btrfs_root *root, struct btrfs_path *path,
4176 struct extent_buffer *leaf;
4177 struct btrfs_item *item;
4179 unsigned int data_end;
4180 unsigned int old_data;
4181 unsigned int old_size;
4183 struct btrfs_map_token token;
4185 btrfs_init_map_token(&token);
4187 leaf = path->nodes[0];
4189 nritems = btrfs_header_nritems(leaf);
4190 data_end = leaf_data_end(root, leaf);
4192 if (btrfs_leaf_free_space(root, leaf) < data_size) {
4193 btrfs_print_leaf(root, leaf);
4196 slot = path->slots[0];
4197 old_data = btrfs_item_end_nr(leaf, slot);
4200 if (slot >= nritems) {
4201 btrfs_print_leaf(root, leaf);
4202 printk(KERN_CRIT "slot %d too large, nritems %d\n",
4208 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4210 /* first correct the data pointers */
4211 for (i = slot; i < nritems; i++) {
4213 item = btrfs_item_nr(leaf, i);
4215 ioff = btrfs_token_item_offset(leaf, item, &token);
4216 btrfs_set_token_item_offset(leaf, item,
4217 ioff - data_size, &token);
4220 /* shift the data */
4221 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
4222 data_end - data_size, btrfs_leaf_data(leaf) +
4223 data_end, old_data - data_end);
4225 data_end = old_data;
4226 old_size = btrfs_item_size_nr(leaf, slot);
4227 item = btrfs_item_nr(leaf, slot);
4228 btrfs_set_item_size(leaf, item, old_size + data_size);
4229 btrfs_mark_buffer_dirty(leaf);
4231 if (btrfs_leaf_free_space(root, leaf) < 0) {
4232 btrfs_print_leaf(root, leaf);
4238 * Given a key and some data, insert items into the tree.
4239 * This does all the path init required, making room in the tree if needed.
4240 * Returns the number of keys that were inserted.
4242 int btrfs_insert_some_items(struct btrfs_trans_handle *trans,
4243 struct btrfs_root *root,
4244 struct btrfs_path *path,
4245 struct btrfs_key *cpu_key, u32 *data_size,
4248 struct extent_buffer *leaf;
4249 struct btrfs_item *item;
4256 unsigned int data_end;
4257 struct btrfs_disk_key disk_key;
4258 struct btrfs_key found_key;
4259 struct btrfs_map_token token;
4261 btrfs_init_map_token(&token);
4263 for (i = 0; i < nr; i++) {
4264 if (total_size + data_size[i] + sizeof(struct btrfs_item) >
4265 BTRFS_LEAF_DATA_SIZE(root)) {
4269 total_data += data_size[i];
4270 total_size += data_size[i] + sizeof(struct btrfs_item);
4274 ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
4280 leaf = path->nodes[0];
4282 nritems = btrfs_header_nritems(leaf);
4283 data_end = leaf_data_end(root, leaf);
4285 if (btrfs_leaf_free_space(root, leaf) < total_size) {
4286 for (i = nr; i >= 0; i--) {
4287 total_data -= data_size[i];
4288 total_size -= data_size[i] + sizeof(struct btrfs_item);
4289 if (total_size < btrfs_leaf_free_space(root, leaf))
4295 slot = path->slots[0];
4298 if (slot != nritems) {
4299 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
4301 item = btrfs_item_nr(leaf, slot);
4302 btrfs_item_key_to_cpu(leaf, &found_key, slot);
4304 /* figure out how many keys we can insert in here */
4305 total_data = data_size[0];
4306 for (i = 1; i < nr; i++) {
4307 if (btrfs_comp_cpu_keys(&found_key, cpu_key + i) <= 0)
4309 total_data += data_size[i];
4313 if (old_data < data_end) {
4314 btrfs_print_leaf(root, leaf);
4315 printk(KERN_CRIT "slot %d old_data %d data_end %d\n",
4316 slot, old_data, data_end);
4320 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4322 /* first correct the data pointers */
4323 for (i = slot; i < nritems; i++) {
4326 item = btrfs_item_nr(leaf, i);
4327 ioff = btrfs_token_item_offset(leaf, item, &token);
4328 btrfs_set_token_item_offset(leaf, item,
4329 ioff - total_data, &token);
4331 /* shift the items */
4332 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
4333 btrfs_item_nr_offset(slot),
4334 (nritems - slot) * sizeof(struct btrfs_item));
4336 /* shift the data */
4337 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
4338 data_end - total_data, btrfs_leaf_data(leaf) +
4339 data_end, old_data - data_end);
4340 data_end = old_data;
4343 * this sucks but it has to be done, if we are inserting at
4344 * the end of the leaf only insert 1 of the items, since we
4345 * have no way of knowing whats on the next leaf and we'd have
4346 * to drop our current locks to figure it out
4351 /* setup the item for the new data */
4352 for (i = 0; i < nr; i++) {
4353 btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
4354 btrfs_set_item_key(leaf, &disk_key, slot + i);
4355 item = btrfs_item_nr(leaf, slot + i);
4356 btrfs_set_token_item_offset(leaf, item,
4357 data_end - data_size[i], &token);
4358 data_end -= data_size[i];
4359 btrfs_set_token_item_size(leaf, item, data_size[i], &token);
4361 btrfs_set_header_nritems(leaf, nritems + nr);
4362 btrfs_mark_buffer_dirty(leaf);
4366 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
4367 fixup_low_keys(trans, root, path, &disk_key, 1);
4370 if (btrfs_leaf_free_space(root, leaf) < 0) {
4371 btrfs_print_leaf(root, leaf);
4381 * this is a helper for btrfs_insert_empty_items, the main goal here is
4382 * to save stack depth by doing the bulk of the work in a function
4383 * that doesn't call btrfs_search_slot
4385 void setup_items_for_insert(struct btrfs_trans_handle *trans,
4386 struct btrfs_root *root, struct btrfs_path *path,
4387 struct btrfs_key *cpu_key, u32 *data_size,
4388 u32 total_data, u32 total_size, int nr)
4390 struct btrfs_item *item;
4393 unsigned int data_end;
4394 struct btrfs_disk_key disk_key;
4395 struct extent_buffer *leaf;
4397 struct btrfs_map_token token;
4399 btrfs_init_map_token(&token);
4401 leaf = path->nodes[0];
4402 slot = path->slots[0];
4404 nritems = btrfs_header_nritems(leaf);
4405 data_end = leaf_data_end(root, leaf);
4407 if (btrfs_leaf_free_space(root, leaf) < total_size) {
4408 btrfs_print_leaf(root, leaf);
4409 printk(KERN_CRIT "not enough freespace need %u have %d\n",
4410 total_size, btrfs_leaf_free_space(root, leaf));
4414 if (slot != nritems) {
4415 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
4417 if (old_data < data_end) {
4418 btrfs_print_leaf(root, leaf);
4419 printk(KERN_CRIT "slot %d old_data %d data_end %d\n",
4420 slot, old_data, data_end);
4424 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4426 /* first correct the data pointers */
4427 for (i = slot; i < nritems; i++) {
4430 item = btrfs_item_nr(leaf, i);
4431 ioff = btrfs_token_item_offset(leaf, item, &token);
4432 btrfs_set_token_item_offset(leaf, item,
4433 ioff - total_data, &token);
4435 /* shift the items */
4436 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
4437 btrfs_item_nr_offset(slot),
4438 (nritems - slot) * sizeof(struct btrfs_item));
4440 /* shift the data */
4441 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
4442 data_end - total_data, btrfs_leaf_data(leaf) +
4443 data_end, old_data - data_end);
4444 data_end = old_data;
4447 /* setup the item for the new data */
4448 for (i = 0; i < nr; i++) {
4449 btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
4450 btrfs_set_item_key(leaf, &disk_key, slot + i);
4451 item = btrfs_item_nr(leaf, slot + i);
4452 btrfs_set_token_item_offset(leaf, item,
4453 data_end - data_size[i], &token);
4454 data_end -= data_size[i];
4455 btrfs_set_token_item_size(leaf, item, data_size[i], &token);
4458 btrfs_set_header_nritems(leaf, nritems + nr);
4461 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
4462 fixup_low_keys(trans, root, path, &disk_key, 1);
4464 btrfs_unlock_up_safe(path, 1);
4465 btrfs_mark_buffer_dirty(leaf);
4467 if (btrfs_leaf_free_space(root, leaf) < 0) {
4468 btrfs_print_leaf(root, leaf);
4474 * Given a key and some data, insert items into the tree.
4475 * This does all the path init required, making room in the tree if needed.
4477 int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
4478 struct btrfs_root *root,
4479 struct btrfs_path *path,
4480 struct btrfs_key *cpu_key, u32 *data_size,
4489 for (i = 0; i < nr; i++)
4490 total_data += data_size[i];
4492 total_size = total_data + (nr * sizeof(struct btrfs_item));
4493 ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
4499 slot = path->slots[0];
4502 setup_items_for_insert(trans, root, path, cpu_key, data_size,
4503 total_data, total_size, nr);
4508 * Given a key and some data, insert an item into the tree.
4509 * This does all the path init required, making room in the tree if needed.
4511 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
4512 *root, struct btrfs_key *cpu_key, void *data, u32
4516 struct btrfs_path *path;
4517 struct extent_buffer *leaf;
4520 path = btrfs_alloc_path();
4523 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
4525 leaf = path->nodes[0];
4526 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
4527 write_extent_buffer(leaf, data, ptr, data_size);
4528 btrfs_mark_buffer_dirty(leaf);
4530 btrfs_free_path(path);
4535 * delete the pointer from a given node.
4537 * the tree should have been previously balanced so the deletion does not
4540 static void del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
4541 struct btrfs_path *path, int level, int slot,
4544 struct extent_buffer *parent = path->nodes[level];
4548 nritems = btrfs_header_nritems(parent);
4549 if (slot != nritems - 1) {
4550 if (tree_mod_log && level)
4551 tree_mod_log_eb_move(root->fs_info, parent, slot,
4552 slot + 1, nritems - slot - 1);
4553 memmove_extent_buffer(parent,
4554 btrfs_node_key_ptr_offset(slot),
4555 btrfs_node_key_ptr_offset(slot + 1),
4556 sizeof(struct btrfs_key_ptr) *
4557 (nritems - slot - 1));
4558 } else if (tree_mod_log && level) {
4559 ret = tree_mod_log_insert_key(root->fs_info, parent, slot,
4560 MOD_LOG_KEY_REMOVE);
4565 btrfs_set_header_nritems(parent, nritems);
4566 if (nritems == 0 && parent == root->node) {
4567 BUG_ON(btrfs_header_level(root->node) != 1);
4568 /* just turn the root into a leaf and break */
4569 btrfs_set_header_level(root->node, 0);
4570 } else if (slot == 0) {
4571 struct btrfs_disk_key disk_key;
4573 btrfs_node_key(parent, &disk_key, 0);
4574 fixup_low_keys(trans, root, path, &disk_key, level + 1);
4576 btrfs_mark_buffer_dirty(parent);
4580 * a helper function to delete the leaf pointed to by path->slots[1] and
4583 * This deletes the pointer in path->nodes[1] and frees the leaf
4584 * block extent. zero is returned if it all worked out, < 0 otherwise.
4586 * The path must have already been setup for deleting the leaf, including
4587 * all the proper balancing. path->nodes[1] must be locked.
4589 static noinline void btrfs_del_leaf(struct btrfs_trans_handle *trans,
4590 struct btrfs_root *root,
4591 struct btrfs_path *path,
4592 struct extent_buffer *leaf)
4594 WARN_ON(btrfs_header_generation(leaf) != trans->transid);
4595 del_ptr(trans, root, path, 1, path->slots[1], 1);
4598 * btrfs_free_extent is expensive, we want to make sure we
4599 * aren't holding any locks when we call it
4601 btrfs_unlock_up_safe(path, 0);
4603 root_sub_used(root, leaf->len);
4605 extent_buffer_get(leaf);
4606 btrfs_free_tree_block(trans, root, leaf, 0, 1);
4607 free_extent_buffer_stale(leaf);
4610 * delete the item at the leaf level in path. If that empties
4611 * the leaf, remove it from the tree
4613 int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
4614 struct btrfs_path *path, int slot, int nr)
4616 struct extent_buffer *leaf;
4617 struct btrfs_item *item;
4624 struct btrfs_map_token token;
4626 btrfs_init_map_token(&token);
4628 leaf = path->nodes[0];
4629 last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
4631 for (i = 0; i < nr; i++)
4632 dsize += btrfs_item_size_nr(leaf, slot + i);
4634 nritems = btrfs_header_nritems(leaf);
4636 if (slot + nr != nritems) {
4637 int data_end = leaf_data_end(root, leaf);
4639 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
4641 btrfs_leaf_data(leaf) + data_end,
4642 last_off - data_end);
4644 for (i = slot + nr; i < nritems; i++) {
4647 item = btrfs_item_nr(leaf, i);
4648 ioff = btrfs_token_item_offset(leaf, item, &token);
4649 btrfs_set_token_item_offset(leaf, item,
4650 ioff + dsize, &token);
4653 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
4654 btrfs_item_nr_offset(slot + nr),
4655 sizeof(struct btrfs_item) *
4656 (nritems - slot - nr));
4658 btrfs_set_header_nritems(leaf, nritems - nr);
4661 /* delete the leaf if we've emptied it */
4663 if (leaf == root->node) {
4664 btrfs_set_header_level(leaf, 0);
4666 btrfs_set_path_blocking(path);
4667 clean_tree_block(trans, root, leaf);
4668 btrfs_del_leaf(trans, root, path, leaf);
4671 int used = leaf_space_used(leaf, 0, nritems);
4673 struct btrfs_disk_key disk_key;
4675 btrfs_item_key(leaf, &disk_key, 0);
4676 fixup_low_keys(trans, root, path, &disk_key, 1);
4679 /* delete the leaf if it is mostly empty */
4680 if (used < BTRFS_LEAF_DATA_SIZE(root) / 3) {
4681 /* push_leaf_left fixes the path.
4682 * make sure the path still points to our leaf
4683 * for possible call to del_ptr below
4685 slot = path->slots[1];
4686 extent_buffer_get(leaf);
4688 btrfs_set_path_blocking(path);
4689 wret = push_leaf_left(trans, root, path, 1, 1,
4691 if (wret < 0 && wret != -ENOSPC)
4694 if (path->nodes[0] == leaf &&
4695 btrfs_header_nritems(leaf)) {
4696 wret = push_leaf_right(trans, root, path, 1,
4698 if (wret < 0 && wret != -ENOSPC)
4702 if (btrfs_header_nritems(leaf) == 0) {
4703 path->slots[1] = slot;
4704 btrfs_del_leaf(trans, root, path, leaf);
4705 free_extent_buffer(leaf);
4708 /* if we're still in the path, make sure
4709 * we're dirty. Otherwise, one of the
4710 * push_leaf functions must have already
4711 * dirtied this buffer
4713 if (path->nodes[0] == leaf)
4714 btrfs_mark_buffer_dirty(leaf);
4715 free_extent_buffer(leaf);
4718 btrfs_mark_buffer_dirty(leaf);
4725 * search the tree again to find a leaf with lesser keys
4726 * returns 0 if it found something or 1 if there are no lesser leaves.
4727 * returns < 0 on io errors.
4729 * This may release the path, and so you may lose any locks held at the
4732 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
4734 struct btrfs_key key;
4735 struct btrfs_disk_key found_key;
4738 btrfs_item_key_to_cpu(path->nodes[0], &key, 0);
4742 else if (key.type > 0)
4744 else if (key.objectid > 0)
4749 btrfs_release_path(path);
4750 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4753 btrfs_item_key(path->nodes[0], &found_key, 0);
4754 ret = comp_keys(&found_key, &key);
4761 * A helper function to walk down the tree starting at min_key, and looking
4762 * for nodes or leaves that are either in cache or have a minimum
4763 * transaction id. This is used by the btree defrag code, and tree logging
4765 * This does not cow, but it does stuff the starting key it finds back
4766 * into min_key, so you can call btrfs_search_slot with cow=1 on the
4767 * key and get a writable path.
4769 * This does lock as it descends, and path->keep_locks should be set
4770 * to 1 by the caller.
4772 * This honors path->lowest_level to prevent descent past a given level
4775 * min_trans indicates the oldest transaction that you are interested
4776 * in walking through. Any nodes or leaves older than min_trans are
4777 * skipped over (without reading them).
4779 * returns zero if something useful was found, < 0 on error and 1 if there
4780 * was nothing in the tree that matched the search criteria.
4782 int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
4783 struct btrfs_key *max_key,
4784 struct btrfs_path *path, int cache_only,
4787 struct extent_buffer *cur;
4788 struct btrfs_key found_key;
4795 WARN_ON(!path->keep_locks);
4797 cur = btrfs_read_lock_root_node(root);
4798 level = btrfs_header_level(cur);
4799 WARN_ON(path->nodes[level]);
4800 path->nodes[level] = cur;
4801 path->locks[level] = BTRFS_READ_LOCK;
4803 if (btrfs_header_generation(cur) < min_trans) {
4808 nritems = btrfs_header_nritems(cur);
4809 level = btrfs_header_level(cur);
4810 sret = bin_search(cur, min_key, level, &slot);
4812 /* at the lowest level, we're done, setup the path and exit */
4813 if (level == path->lowest_level) {
4814 if (slot >= nritems)
4817 path->slots[level] = slot;
4818 btrfs_item_key_to_cpu(cur, &found_key, slot);
4821 if (sret && slot > 0)
4824 * check this node pointer against the cache_only and
4825 * min_trans parameters. If it isn't in cache or is too
4826 * old, skip to the next one.
4828 while (slot < nritems) {
4831 struct extent_buffer *tmp;
4832 struct btrfs_disk_key disk_key;
4834 blockptr = btrfs_node_blockptr(cur, slot);
4835 gen = btrfs_node_ptr_generation(cur, slot);
4836 if (gen < min_trans) {
4844 btrfs_node_key(cur, &disk_key, slot);
4845 if (comp_keys(&disk_key, max_key) >= 0) {
4851 tmp = btrfs_find_tree_block(root, blockptr,
4852 btrfs_level_size(root, level - 1));
4854 if (tmp && btrfs_buffer_uptodate(tmp, gen, 1) > 0) {
4855 free_extent_buffer(tmp);
4859 free_extent_buffer(tmp);
4864 * we didn't find a candidate key in this node, walk forward
4865 * and find another one
4867 if (slot >= nritems) {
4868 path->slots[level] = slot;
4869 btrfs_set_path_blocking(path);
4870 sret = btrfs_find_next_key(root, path, min_key, level,
4871 cache_only, min_trans);
4873 btrfs_release_path(path);
4879 /* save our key for returning back */
4880 btrfs_node_key_to_cpu(cur, &found_key, slot);
4881 path->slots[level] = slot;
4882 if (level == path->lowest_level) {
4884 unlock_up(path, level, 1, 0, NULL);
4887 btrfs_set_path_blocking(path);
4888 cur = read_node_slot(root, cur, slot);
4889 BUG_ON(!cur); /* -ENOMEM */
4891 btrfs_tree_read_lock(cur);
4893 path->locks[level - 1] = BTRFS_READ_LOCK;
4894 path->nodes[level - 1] = cur;
4895 unlock_up(path, level, 1, 0, NULL);
4896 btrfs_clear_path_blocking(path, NULL, 0);
4900 memcpy(min_key, &found_key, sizeof(found_key));
4901 btrfs_set_path_blocking(path);
4906 * this is similar to btrfs_next_leaf, but does not try to preserve
4907 * and fixup the path. It looks for and returns the next key in the
4908 * tree based on the current path and the cache_only and min_trans
4911 * 0 is returned if another key is found, < 0 if there are any errors
4912 * and 1 is returned if there are no higher keys in the tree
4914 * path->keep_locks should be set to 1 on the search made before
4915 * calling this function.
4917 int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
4918 struct btrfs_key *key, int level,
4919 int cache_only, u64 min_trans)
4922 struct extent_buffer *c;
4924 WARN_ON(!path->keep_locks);
4925 while (level < BTRFS_MAX_LEVEL) {
4926 if (!path->nodes[level])
4929 slot = path->slots[level] + 1;
4930 c = path->nodes[level];
4932 if (slot >= btrfs_header_nritems(c)) {
4935 struct btrfs_key cur_key;
4936 if (level + 1 >= BTRFS_MAX_LEVEL ||
4937 !path->nodes[level + 1])
4940 if (path->locks[level + 1]) {
4945 slot = btrfs_header_nritems(c) - 1;
4947 btrfs_item_key_to_cpu(c, &cur_key, slot);
4949 btrfs_node_key_to_cpu(c, &cur_key, slot);
4951 orig_lowest = path->lowest_level;
4952 btrfs_release_path(path);
4953 path->lowest_level = level;
4954 ret = btrfs_search_slot(NULL, root, &cur_key, path,
4956 path->lowest_level = orig_lowest;
4960 c = path->nodes[level];
4961 slot = path->slots[level];
4968 btrfs_item_key_to_cpu(c, key, slot);
4970 u64 blockptr = btrfs_node_blockptr(c, slot);
4971 u64 gen = btrfs_node_ptr_generation(c, slot);
4974 struct extent_buffer *cur;
4975 cur = btrfs_find_tree_block(root, blockptr,
4976 btrfs_level_size(root, level - 1));
4978 btrfs_buffer_uptodate(cur, gen, 1) <= 0) {
4981 free_extent_buffer(cur);
4984 free_extent_buffer(cur);
4986 if (gen < min_trans) {
4990 btrfs_node_key_to_cpu(c, key, slot);
4998 * search the tree again to find a leaf with greater keys
4999 * returns 0 if it found something or 1 if there are no greater leaves.
5000 * returns < 0 on io errors.
5002 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
5006 struct extent_buffer *c;
5007 struct extent_buffer *next;
5008 struct btrfs_key key;
5011 int old_spinning = path->leave_spinning;
5012 int next_rw_lock = 0;
5014 nritems = btrfs_header_nritems(path->nodes[0]);
5018 btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1);
5023 btrfs_release_path(path);
5025 path->keep_locks = 1;
5026 path->leave_spinning = 1;
5028 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5029 path->keep_locks = 0;
5034 nritems = btrfs_header_nritems(path->nodes[0]);
5036 * by releasing the path above we dropped all our locks. A balance
5037 * could have added more items next to the key that used to be
5038 * at the very end of the block. So, check again here and
5039 * advance the path if there are now more items available.
5041 if (nritems > 0 && path->slots[0] < nritems - 1) {
5048 while (level < BTRFS_MAX_LEVEL) {
5049 if (!path->nodes[level]) {
5054 slot = path->slots[level] + 1;
5055 c = path->nodes[level];
5056 if (slot >= btrfs_header_nritems(c)) {
5058 if (level == BTRFS_MAX_LEVEL) {
5066 btrfs_tree_unlock_rw(next, next_rw_lock);
5067 free_extent_buffer(next);
5071 next_rw_lock = path->locks[level];
5072 ret = read_block_for_search(NULL, root, path, &next, level,
5078 btrfs_release_path(path);
5082 if (!path->skip_locking) {
5083 ret = btrfs_try_tree_read_lock(next);
5085 btrfs_set_path_blocking(path);
5086 btrfs_tree_read_lock(next);
5087 btrfs_clear_path_blocking(path, next,
5090 next_rw_lock = BTRFS_READ_LOCK;
5094 path->slots[level] = slot;
5097 c = path->nodes[level];
5098 if (path->locks[level])
5099 btrfs_tree_unlock_rw(c, path->locks[level]);
5101 free_extent_buffer(c);
5102 path->nodes[level] = next;
5103 path->slots[level] = 0;
5104 if (!path->skip_locking)
5105 path->locks[level] = next_rw_lock;
5109 ret = read_block_for_search(NULL, root, path, &next, level,
5115 btrfs_release_path(path);
5119 if (!path->skip_locking) {
5120 ret = btrfs_try_tree_read_lock(next);
5122 btrfs_set_path_blocking(path);
5123 btrfs_tree_read_lock(next);
5124 btrfs_clear_path_blocking(path, next,
5127 next_rw_lock = BTRFS_READ_LOCK;
5132 unlock_up(path, 0, 1, 0, NULL);
5133 path->leave_spinning = old_spinning;
5135 btrfs_set_path_blocking(path);
5141 * this uses btrfs_prev_leaf to walk backwards in the tree, and keeps
5142 * searching until it gets past min_objectid or finds an item of 'type'
5144 * returns 0 if something is found, 1 if nothing was found and < 0 on error
5146 int btrfs_previous_item(struct btrfs_root *root,
5147 struct btrfs_path *path, u64 min_objectid,
5150 struct btrfs_key found_key;
5151 struct extent_buffer *leaf;
5156 if (path->slots[0] == 0) {
5157 btrfs_set_path_blocking(path);
5158 ret = btrfs_prev_leaf(root, path);
5164 leaf = path->nodes[0];
5165 nritems = btrfs_header_nritems(leaf);
5168 if (path->slots[0] == nritems)
5171 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5172 if (found_key.objectid < min_objectid)
5174 if (found_key.type == type)
5176 if (found_key.objectid == min_objectid &&
5177 found_key.type < type)