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_root *root, struct btrfs_path *path,
42 static void tree_mod_log_free_eb(struct btrfs_fs_info *fs_info,
43 struct extent_buffer *eb);
44 static int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path);
46 struct btrfs_path *btrfs_alloc_path(void)
48 struct btrfs_path *path;
49 path = kmem_cache_zalloc(btrfs_path_cachep, GFP_NOFS);
54 * set all locked nodes in the path to blocking locks. This should
55 * be done before scheduling
57 noinline void btrfs_set_path_blocking(struct btrfs_path *p)
60 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
61 if (!p->nodes[i] || !p->locks[i])
63 btrfs_set_lock_blocking_rw(p->nodes[i], p->locks[i]);
64 if (p->locks[i] == BTRFS_READ_LOCK)
65 p->locks[i] = BTRFS_READ_LOCK_BLOCKING;
66 else if (p->locks[i] == BTRFS_WRITE_LOCK)
67 p->locks[i] = BTRFS_WRITE_LOCK_BLOCKING;
72 * reset all the locked nodes in the patch to spinning locks.
74 * held is used to keep lockdep happy, when lockdep is enabled
75 * we set held to a blocking lock before we go around and
76 * retake all the spinlocks in the path. You can safely use NULL
79 noinline void btrfs_clear_path_blocking(struct btrfs_path *p,
80 struct extent_buffer *held, int held_rw)
84 #ifdef CONFIG_DEBUG_LOCK_ALLOC
85 /* lockdep really cares that we take all of these spinlocks
86 * in the right order. If any of the locks in the path are not
87 * currently blocking, it is going to complain. So, make really
88 * really sure by forcing the path to blocking before we clear
92 btrfs_set_lock_blocking_rw(held, held_rw);
93 if (held_rw == BTRFS_WRITE_LOCK)
94 held_rw = BTRFS_WRITE_LOCK_BLOCKING;
95 else if (held_rw == BTRFS_READ_LOCK)
96 held_rw = BTRFS_READ_LOCK_BLOCKING;
98 btrfs_set_path_blocking(p);
101 for (i = BTRFS_MAX_LEVEL - 1; i >= 0; i--) {
102 if (p->nodes[i] && p->locks[i]) {
103 btrfs_clear_lock_blocking_rw(p->nodes[i], p->locks[i]);
104 if (p->locks[i] == BTRFS_WRITE_LOCK_BLOCKING)
105 p->locks[i] = BTRFS_WRITE_LOCK;
106 else if (p->locks[i] == BTRFS_READ_LOCK_BLOCKING)
107 p->locks[i] = BTRFS_READ_LOCK;
111 #ifdef CONFIG_DEBUG_LOCK_ALLOC
113 btrfs_clear_lock_blocking_rw(held, held_rw);
117 /* this also releases the path */
118 void btrfs_free_path(struct btrfs_path *p)
122 btrfs_release_path(p);
123 kmem_cache_free(btrfs_path_cachep, p);
127 * path release drops references on the extent buffers in the path
128 * and it drops any locks held by this path
130 * It is safe to call this on paths that no locks or extent buffers held.
132 noinline void btrfs_release_path(struct btrfs_path *p)
136 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
141 btrfs_tree_unlock_rw(p->nodes[i], p->locks[i]);
144 free_extent_buffer(p->nodes[i]);
150 * safely gets a reference on the root node of a tree. A lock
151 * is not taken, so a concurrent writer may put a different node
152 * at the root of the tree. See btrfs_lock_root_node for the
155 * The extent buffer returned by this has a reference taken, so
156 * it won't disappear. It may stop being the root of the tree
157 * at any time because there are no locks held.
159 struct extent_buffer *btrfs_root_node(struct btrfs_root *root)
161 struct extent_buffer *eb;
165 eb = rcu_dereference(root->node);
168 * RCU really hurts here, we could free up the root node because
169 * it was cow'ed but we may not get the new root node yet so do
170 * the inc_not_zero dance and if it doesn't work then
171 * synchronize_rcu and try again.
173 if (atomic_inc_not_zero(&eb->refs)) {
183 /* loop around taking references on and locking the root node of the
184 * tree until you end up with a lock on the root. A locked buffer
185 * is returned, with a reference held.
187 struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root)
189 struct extent_buffer *eb;
192 eb = btrfs_root_node(root);
194 if (eb == root->node)
196 btrfs_tree_unlock(eb);
197 free_extent_buffer(eb);
202 /* loop around taking references on and locking the root node of the
203 * tree until you end up with a lock on the root. A locked buffer
204 * is returned, with a reference held.
206 static struct extent_buffer *btrfs_read_lock_root_node(struct btrfs_root *root)
208 struct extent_buffer *eb;
211 eb = btrfs_root_node(root);
212 btrfs_tree_read_lock(eb);
213 if (eb == root->node)
215 btrfs_tree_read_unlock(eb);
216 free_extent_buffer(eb);
221 /* cowonly root (everything not a reference counted cow subvolume), just get
222 * put onto a simple dirty list. transaction.c walks this to make sure they
223 * get properly updated on disk.
225 static void add_root_to_dirty_list(struct btrfs_root *root)
227 spin_lock(&root->fs_info->trans_lock);
228 if (root->track_dirty && list_empty(&root->dirty_list)) {
229 list_add(&root->dirty_list,
230 &root->fs_info->dirty_cowonly_roots);
232 spin_unlock(&root->fs_info->trans_lock);
236 * used by snapshot creation to make a copy of a root for a tree with
237 * a given objectid. The buffer with the new root node is returned in
238 * cow_ret, and this func returns zero on success or a negative error code.
240 int btrfs_copy_root(struct btrfs_trans_handle *trans,
241 struct btrfs_root *root,
242 struct extent_buffer *buf,
243 struct extent_buffer **cow_ret, u64 new_root_objectid)
245 struct extent_buffer *cow;
248 struct btrfs_disk_key disk_key;
250 WARN_ON(root->ref_cows && trans->transid !=
251 root->fs_info->running_transaction->transid);
252 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
254 level = btrfs_header_level(buf);
256 btrfs_item_key(buf, &disk_key, 0);
258 btrfs_node_key(buf, &disk_key, 0);
260 cow = btrfs_alloc_free_block(trans, root, buf->len, 0,
261 new_root_objectid, &disk_key, level,
266 copy_extent_buffer(cow, buf, 0, 0, cow->len);
267 btrfs_set_header_bytenr(cow, cow->start);
268 btrfs_set_header_generation(cow, trans->transid);
269 btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV);
270 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN |
271 BTRFS_HEADER_FLAG_RELOC);
272 if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID)
273 btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC);
275 btrfs_set_header_owner(cow, new_root_objectid);
277 write_extent_buffer(cow, root->fs_info->fsid,
278 (unsigned long)btrfs_header_fsid(cow),
281 WARN_ON(btrfs_header_generation(buf) > trans->transid);
282 if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID)
283 ret = btrfs_inc_ref(trans, root, cow, 1, 1);
285 ret = btrfs_inc_ref(trans, root, cow, 0, 1);
290 btrfs_mark_buffer_dirty(cow);
299 MOD_LOG_KEY_REMOVE_WHILE_FREEING,
300 MOD_LOG_KEY_REMOVE_WHILE_MOVING,
302 MOD_LOG_ROOT_REPLACE,
305 struct tree_mod_move {
310 struct tree_mod_root {
315 struct tree_mod_elem {
317 u64 index; /* shifted logical */
321 /* this is used for MOD_LOG_KEY_* and MOD_LOG_MOVE_KEYS operations */
324 /* this is used for MOD_LOG_KEY* and MOD_LOG_ROOT_REPLACE */
327 /* those are used for op == MOD_LOG_KEY_{REPLACE,REMOVE} */
328 struct btrfs_disk_key key;
331 /* this is used for op == MOD_LOG_MOVE_KEYS */
332 struct tree_mod_move move;
334 /* this is used for op == MOD_LOG_ROOT_REPLACE */
335 struct tree_mod_root old_root;
338 static inline void tree_mod_log_read_lock(struct btrfs_fs_info *fs_info)
340 read_lock(&fs_info->tree_mod_log_lock);
343 static inline void tree_mod_log_read_unlock(struct btrfs_fs_info *fs_info)
345 read_unlock(&fs_info->tree_mod_log_lock);
348 static inline void tree_mod_log_write_lock(struct btrfs_fs_info *fs_info)
350 write_lock(&fs_info->tree_mod_log_lock);
353 static inline void tree_mod_log_write_unlock(struct btrfs_fs_info *fs_info)
355 write_unlock(&fs_info->tree_mod_log_lock);
359 * Increment the upper half of tree_mod_seq, set lower half zero.
361 * Must be called with fs_info->tree_mod_seq_lock held.
363 static inline u64 btrfs_inc_tree_mod_seq_major(struct btrfs_fs_info *fs_info)
365 u64 seq = atomic64_read(&fs_info->tree_mod_seq);
366 seq &= 0xffffffff00000000ull;
368 atomic64_set(&fs_info->tree_mod_seq, seq);
373 * Increment the lower half of tree_mod_seq.
375 * Must be called with fs_info->tree_mod_seq_lock held. The way major numbers
376 * are generated should not technically require a spin lock here. (Rationale:
377 * incrementing the minor while incrementing the major seq number is between its
378 * atomic64_read and atomic64_set calls doesn't duplicate sequence numbers, it
379 * just returns a unique sequence number as usual.) We have decided to leave
380 * that requirement in here and rethink it once we notice it really imposes a
381 * problem on some workload.
383 static inline u64 btrfs_inc_tree_mod_seq_minor(struct btrfs_fs_info *fs_info)
385 return atomic64_inc_return(&fs_info->tree_mod_seq);
389 * return the last minor in the previous major tree_mod_seq number
391 u64 btrfs_tree_mod_seq_prev(u64 seq)
393 return (seq & 0xffffffff00000000ull) - 1ull;
397 * This adds a new blocker to the tree mod log's blocker list if the @elem
398 * passed does not already have a sequence number set. So when a caller expects
399 * to record tree modifications, it should ensure to set elem->seq to zero
400 * before calling btrfs_get_tree_mod_seq.
401 * Returns a fresh, unused tree log modification sequence number, even if no new
404 u64 btrfs_get_tree_mod_seq(struct btrfs_fs_info *fs_info,
405 struct seq_list *elem)
409 tree_mod_log_write_lock(fs_info);
410 spin_lock(&fs_info->tree_mod_seq_lock);
412 elem->seq = btrfs_inc_tree_mod_seq_major(fs_info);
413 list_add_tail(&elem->list, &fs_info->tree_mod_seq_list);
415 seq = btrfs_inc_tree_mod_seq_minor(fs_info);
416 spin_unlock(&fs_info->tree_mod_seq_lock);
417 tree_mod_log_write_unlock(fs_info);
422 void btrfs_put_tree_mod_seq(struct btrfs_fs_info *fs_info,
423 struct seq_list *elem)
425 struct rb_root *tm_root;
426 struct rb_node *node;
427 struct rb_node *next;
428 struct seq_list *cur_elem;
429 struct tree_mod_elem *tm;
430 u64 min_seq = (u64)-1;
431 u64 seq_putting = elem->seq;
436 spin_lock(&fs_info->tree_mod_seq_lock);
437 list_del(&elem->list);
440 list_for_each_entry(cur_elem, &fs_info->tree_mod_seq_list, list) {
441 if (cur_elem->seq < min_seq) {
442 if (seq_putting > cur_elem->seq) {
444 * blocker with lower sequence number exists, we
445 * cannot remove anything from the log
447 spin_unlock(&fs_info->tree_mod_seq_lock);
450 min_seq = cur_elem->seq;
453 spin_unlock(&fs_info->tree_mod_seq_lock);
456 * anything that's lower than the lowest existing (read: blocked)
457 * sequence number can be removed from the tree.
459 tree_mod_log_write_lock(fs_info);
460 tm_root = &fs_info->tree_mod_log;
461 for (node = rb_first(tm_root); node; node = next) {
462 next = rb_next(node);
463 tm = container_of(node, struct tree_mod_elem, node);
464 if (tm->seq > min_seq)
466 rb_erase(node, tm_root);
469 tree_mod_log_write_unlock(fs_info);
473 * key order of the log:
476 * the index is the shifted logical of the *new* root node for root replace
477 * operations, or the shifted logical of the affected block for all other
481 __tree_mod_log_insert(struct btrfs_fs_info *fs_info, struct tree_mod_elem *tm)
483 struct rb_root *tm_root;
484 struct rb_node **new;
485 struct rb_node *parent = NULL;
486 struct tree_mod_elem *cur;
488 BUG_ON(!tm || !tm->seq);
490 tm_root = &fs_info->tree_mod_log;
491 new = &tm_root->rb_node;
493 cur = container_of(*new, struct tree_mod_elem, node);
495 if (cur->index < tm->index)
496 new = &((*new)->rb_left);
497 else if (cur->index > tm->index)
498 new = &((*new)->rb_right);
499 else if (cur->seq < tm->seq)
500 new = &((*new)->rb_left);
501 else if (cur->seq > tm->seq)
502 new = &((*new)->rb_right);
509 rb_link_node(&tm->node, parent, new);
510 rb_insert_color(&tm->node, tm_root);
515 * Determines if logging can be omitted. Returns 1 if it can. Otherwise, it
516 * returns zero with the tree_mod_log_lock acquired. The caller must hold
517 * this until all tree mod log insertions are recorded in the rb tree and then
518 * call tree_mod_log_write_unlock() to release.
520 static inline int tree_mod_dont_log(struct btrfs_fs_info *fs_info,
521 struct extent_buffer *eb) {
523 if (list_empty(&(fs_info)->tree_mod_seq_list))
525 if (eb && btrfs_header_level(eb) == 0)
528 tree_mod_log_write_lock(fs_info);
529 if (list_empty(&fs_info->tree_mod_seq_list)) {
531 * someone emptied the list while we were waiting for the lock.
532 * we must not add to the list when no blocker exists.
534 tree_mod_log_write_unlock(fs_info);
542 * This allocates memory and gets a tree modification sequence number.
544 * Returns <0 on error.
545 * Returns >0 (the added sequence number) on success.
547 static inline int tree_mod_alloc(struct btrfs_fs_info *fs_info, gfp_t flags,
548 struct tree_mod_elem **tm_ret)
550 struct tree_mod_elem *tm;
553 * once we switch from spin locks to something different, we should
554 * honor the flags parameter here.
556 tm = *tm_ret = kzalloc(sizeof(*tm), GFP_ATOMIC);
560 spin_lock(&fs_info->tree_mod_seq_lock);
561 tm->seq = btrfs_inc_tree_mod_seq_minor(fs_info);
562 spin_unlock(&fs_info->tree_mod_seq_lock);
568 __tree_mod_log_insert_key(struct btrfs_fs_info *fs_info,
569 struct extent_buffer *eb, int slot,
570 enum mod_log_op op, gfp_t flags)
573 struct tree_mod_elem *tm;
575 ret = tree_mod_alloc(fs_info, flags, &tm);
579 tm->index = eb->start >> PAGE_CACHE_SHIFT;
580 if (op != MOD_LOG_KEY_ADD) {
581 btrfs_node_key(eb, &tm->key, slot);
582 tm->blockptr = btrfs_node_blockptr(eb, slot);
586 tm->generation = btrfs_node_ptr_generation(eb, slot);
588 return __tree_mod_log_insert(fs_info, tm);
592 tree_mod_log_insert_key_mask(struct btrfs_fs_info *fs_info,
593 struct extent_buffer *eb, int slot,
594 enum mod_log_op op, gfp_t flags)
598 if (tree_mod_dont_log(fs_info, eb))
601 ret = __tree_mod_log_insert_key(fs_info, eb, slot, op, flags);
603 tree_mod_log_write_unlock(fs_info);
608 tree_mod_log_insert_key(struct btrfs_fs_info *fs_info, struct extent_buffer *eb,
609 int slot, enum mod_log_op op)
611 return tree_mod_log_insert_key_mask(fs_info, eb, slot, op, GFP_NOFS);
615 tree_mod_log_insert_key_locked(struct btrfs_fs_info *fs_info,
616 struct extent_buffer *eb, int slot,
619 return __tree_mod_log_insert_key(fs_info, eb, slot, op, GFP_NOFS);
623 tree_mod_log_insert_move(struct btrfs_fs_info *fs_info,
624 struct extent_buffer *eb, int dst_slot, int src_slot,
625 int nr_items, gfp_t flags)
627 struct tree_mod_elem *tm;
631 if (tree_mod_dont_log(fs_info, eb))
635 * When we override something during the move, we log these removals.
636 * This can only happen when we move towards the beginning of the
637 * buffer, i.e. dst_slot < src_slot.
639 for (i = 0; i + dst_slot < src_slot && i < nr_items; i++) {
640 ret = tree_mod_log_insert_key_locked(fs_info, eb, i + dst_slot,
641 MOD_LOG_KEY_REMOVE_WHILE_MOVING);
645 ret = tree_mod_alloc(fs_info, flags, &tm);
649 tm->index = eb->start >> PAGE_CACHE_SHIFT;
651 tm->move.dst_slot = dst_slot;
652 tm->move.nr_items = nr_items;
653 tm->op = MOD_LOG_MOVE_KEYS;
655 ret = __tree_mod_log_insert(fs_info, tm);
657 tree_mod_log_write_unlock(fs_info);
662 __tree_mod_log_free_eb(struct btrfs_fs_info *fs_info, struct extent_buffer *eb)
668 if (btrfs_header_level(eb) == 0)
671 nritems = btrfs_header_nritems(eb);
672 for (i = nritems - 1; i >= 0; i--) {
673 ret = tree_mod_log_insert_key_locked(fs_info, eb, i,
674 MOD_LOG_KEY_REMOVE_WHILE_FREEING);
680 tree_mod_log_insert_root(struct btrfs_fs_info *fs_info,
681 struct extent_buffer *old_root,
682 struct extent_buffer *new_root, gfp_t flags,
685 struct tree_mod_elem *tm;
688 if (tree_mod_dont_log(fs_info, NULL))
692 __tree_mod_log_free_eb(fs_info, old_root);
694 ret = tree_mod_alloc(fs_info, flags, &tm);
698 tm->index = new_root->start >> PAGE_CACHE_SHIFT;
699 tm->old_root.logical = old_root->start;
700 tm->old_root.level = btrfs_header_level(old_root);
701 tm->generation = btrfs_header_generation(old_root);
702 tm->op = MOD_LOG_ROOT_REPLACE;
704 ret = __tree_mod_log_insert(fs_info, tm);
706 tree_mod_log_write_unlock(fs_info);
710 static struct tree_mod_elem *
711 __tree_mod_log_search(struct btrfs_fs_info *fs_info, u64 start, u64 min_seq,
714 struct rb_root *tm_root;
715 struct rb_node *node;
716 struct tree_mod_elem *cur = NULL;
717 struct tree_mod_elem *found = NULL;
718 u64 index = start >> PAGE_CACHE_SHIFT;
720 tree_mod_log_read_lock(fs_info);
721 tm_root = &fs_info->tree_mod_log;
722 node = tm_root->rb_node;
724 cur = container_of(node, struct tree_mod_elem, node);
725 if (cur->index < index) {
726 node = node->rb_left;
727 } else if (cur->index > index) {
728 node = node->rb_right;
729 } else if (cur->seq < min_seq) {
730 node = node->rb_left;
731 } else if (!smallest) {
732 /* we want the node with the highest seq */
734 BUG_ON(found->seq > cur->seq);
736 node = node->rb_left;
737 } else if (cur->seq > min_seq) {
738 /* we want the node with the smallest seq */
740 BUG_ON(found->seq < cur->seq);
742 node = node->rb_right;
748 tree_mod_log_read_unlock(fs_info);
754 * this returns the element from the log with the smallest time sequence
755 * value that's in the log (the oldest log item). any element with a time
756 * sequence lower than min_seq will be ignored.
758 static struct tree_mod_elem *
759 tree_mod_log_search_oldest(struct btrfs_fs_info *fs_info, u64 start,
762 return __tree_mod_log_search(fs_info, start, min_seq, 1);
766 * this returns the element from the log with the largest time sequence
767 * value that's in the log (the most recent log item). any element with
768 * a time sequence lower than min_seq will be ignored.
770 static struct tree_mod_elem *
771 tree_mod_log_search(struct btrfs_fs_info *fs_info, u64 start, u64 min_seq)
773 return __tree_mod_log_search(fs_info, start, min_seq, 0);
777 tree_mod_log_eb_copy(struct btrfs_fs_info *fs_info, struct extent_buffer *dst,
778 struct extent_buffer *src, unsigned long dst_offset,
779 unsigned long src_offset, int nr_items)
784 if (tree_mod_dont_log(fs_info, NULL))
787 if (btrfs_header_level(dst) == 0 && btrfs_header_level(src) == 0) {
788 tree_mod_log_write_unlock(fs_info);
792 for (i = 0; i < nr_items; i++) {
793 ret = tree_mod_log_insert_key_locked(fs_info, src,
797 ret = tree_mod_log_insert_key_locked(fs_info, dst,
803 tree_mod_log_write_unlock(fs_info);
807 tree_mod_log_eb_move(struct btrfs_fs_info *fs_info, struct extent_buffer *dst,
808 int dst_offset, int src_offset, int nr_items)
811 ret = tree_mod_log_insert_move(fs_info, dst, dst_offset, src_offset,
817 tree_mod_log_set_node_key(struct btrfs_fs_info *fs_info,
818 struct extent_buffer *eb, int slot, int atomic)
822 ret = tree_mod_log_insert_key_mask(fs_info, eb, slot,
824 atomic ? GFP_ATOMIC : GFP_NOFS);
829 tree_mod_log_free_eb(struct btrfs_fs_info *fs_info, struct extent_buffer *eb)
831 if (tree_mod_dont_log(fs_info, eb))
834 __tree_mod_log_free_eb(fs_info, eb);
836 tree_mod_log_write_unlock(fs_info);
840 tree_mod_log_set_root_pointer(struct btrfs_root *root,
841 struct extent_buffer *new_root_node,
845 ret = tree_mod_log_insert_root(root->fs_info, root->node,
846 new_root_node, GFP_NOFS, log_removal);
851 * check if the tree block can be shared by multiple trees
853 int btrfs_block_can_be_shared(struct btrfs_root *root,
854 struct extent_buffer *buf)
857 * Tree blocks not in refernece counted trees and tree roots
858 * are never shared. If a block was allocated after the last
859 * snapshot and the block was not allocated by tree relocation,
860 * we know the block is not shared.
862 if (root->ref_cows &&
863 buf != root->node && buf != root->commit_root &&
864 (btrfs_header_generation(buf) <=
865 btrfs_root_last_snapshot(&root->root_item) ||
866 btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)))
868 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
869 if (root->ref_cows &&
870 btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
876 static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans,
877 struct btrfs_root *root,
878 struct extent_buffer *buf,
879 struct extent_buffer *cow,
889 * Backrefs update rules:
891 * Always use full backrefs for extent pointers in tree block
892 * allocated by tree relocation.
894 * If a shared tree block is no longer referenced by its owner
895 * tree (btrfs_header_owner(buf) == root->root_key.objectid),
896 * use full backrefs for extent pointers in tree block.
898 * If a tree block is been relocating
899 * (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID),
900 * use full backrefs for extent pointers in tree block.
901 * The reason for this is some operations (such as drop tree)
902 * are only allowed for blocks use full backrefs.
905 if (btrfs_block_can_be_shared(root, buf)) {
906 ret = btrfs_lookup_extent_info(trans, root, buf->start,
907 btrfs_header_level(buf), 1,
913 btrfs_std_error(root->fs_info, ret);
918 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
919 btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
920 flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
925 owner = btrfs_header_owner(buf);
926 BUG_ON(owner == BTRFS_TREE_RELOC_OBJECTID &&
927 !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
930 if ((owner == root->root_key.objectid ||
931 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) &&
932 !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) {
933 ret = btrfs_inc_ref(trans, root, buf, 1, 1);
934 BUG_ON(ret); /* -ENOMEM */
936 if (root->root_key.objectid ==
937 BTRFS_TREE_RELOC_OBJECTID) {
938 ret = btrfs_dec_ref(trans, root, buf, 0, 1);
939 BUG_ON(ret); /* -ENOMEM */
940 ret = btrfs_inc_ref(trans, root, cow, 1, 1);
941 BUG_ON(ret); /* -ENOMEM */
943 new_flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
946 if (root->root_key.objectid ==
947 BTRFS_TREE_RELOC_OBJECTID)
948 ret = btrfs_inc_ref(trans, root, cow, 1, 1);
950 ret = btrfs_inc_ref(trans, root, cow, 0, 1);
951 BUG_ON(ret); /* -ENOMEM */
953 if (new_flags != 0) {
954 int level = btrfs_header_level(buf);
956 ret = btrfs_set_disk_extent_flags(trans, root,
959 new_flags, level, 0);
964 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
965 if (root->root_key.objectid ==
966 BTRFS_TREE_RELOC_OBJECTID)
967 ret = btrfs_inc_ref(trans, root, cow, 1, 1);
969 ret = btrfs_inc_ref(trans, root, cow, 0, 1);
970 BUG_ON(ret); /* -ENOMEM */
971 ret = btrfs_dec_ref(trans, root, buf, 1, 1);
972 BUG_ON(ret); /* -ENOMEM */
974 clean_tree_block(trans, root, buf);
981 * does the dirty work in cow of a single block. The parent block (if
982 * supplied) is updated to point to the new cow copy. The new buffer is marked
983 * dirty and returned locked. If you modify the block it needs to be marked
986 * search_start -- an allocation hint for the new block
988 * empty_size -- a hint that you plan on doing more cow. This is the size in
989 * bytes the allocator should try to find free next to the block it returns.
990 * This is just a hint and may be ignored by the allocator.
992 static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
993 struct btrfs_root *root,
994 struct extent_buffer *buf,
995 struct extent_buffer *parent, int parent_slot,
996 struct extent_buffer **cow_ret,
997 u64 search_start, u64 empty_size)
999 struct btrfs_disk_key disk_key;
1000 struct extent_buffer *cow;
1003 int unlock_orig = 0;
1006 if (*cow_ret == buf)
1009 btrfs_assert_tree_locked(buf);
1011 WARN_ON(root->ref_cows && trans->transid !=
1012 root->fs_info->running_transaction->transid);
1013 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
1015 level = btrfs_header_level(buf);
1018 btrfs_item_key(buf, &disk_key, 0);
1020 btrfs_node_key(buf, &disk_key, 0);
1022 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
1024 parent_start = parent->start;
1030 cow = btrfs_alloc_free_block(trans, root, buf->len, parent_start,
1031 root->root_key.objectid, &disk_key,
1032 level, search_start, empty_size);
1034 return PTR_ERR(cow);
1036 /* cow is set to blocking by btrfs_init_new_buffer */
1038 copy_extent_buffer(cow, buf, 0, 0, cow->len);
1039 btrfs_set_header_bytenr(cow, cow->start);
1040 btrfs_set_header_generation(cow, trans->transid);
1041 btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV);
1042 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN |
1043 BTRFS_HEADER_FLAG_RELOC);
1044 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1045 btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC);
1047 btrfs_set_header_owner(cow, root->root_key.objectid);
1049 write_extent_buffer(cow, root->fs_info->fsid,
1050 (unsigned long)btrfs_header_fsid(cow),
1053 ret = update_ref_for_cow(trans, root, buf, cow, &last_ref);
1055 btrfs_abort_transaction(trans, root, ret);
1060 btrfs_reloc_cow_block(trans, root, buf, cow);
1062 if (buf == root->node) {
1063 WARN_ON(parent && parent != buf);
1064 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
1065 btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
1066 parent_start = buf->start;
1070 extent_buffer_get(cow);
1071 tree_mod_log_set_root_pointer(root, cow, 1);
1072 rcu_assign_pointer(root->node, cow);
1074 btrfs_free_tree_block(trans, root, buf, parent_start,
1076 free_extent_buffer(buf);
1077 add_root_to_dirty_list(root);
1079 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1080 parent_start = parent->start;
1084 WARN_ON(trans->transid != btrfs_header_generation(parent));
1085 tree_mod_log_insert_key(root->fs_info, parent, parent_slot,
1086 MOD_LOG_KEY_REPLACE);
1087 btrfs_set_node_blockptr(parent, parent_slot,
1089 btrfs_set_node_ptr_generation(parent, parent_slot,
1091 btrfs_mark_buffer_dirty(parent);
1093 tree_mod_log_free_eb(root->fs_info, buf);
1094 btrfs_free_tree_block(trans, root, buf, parent_start,
1098 btrfs_tree_unlock(buf);
1099 free_extent_buffer_stale(buf);
1100 btrfs_mark_buffer_dirty(cow);
1106 * returns the logical address of the oldest predecessor of the given root.
1107 * entries older than time_seq are ignored.
1109 static struct tree_mod_elem *
1110 __tree_mod_log_oldest_root(struct btrfs_fs_info *fs_info,
1111 struct extent_buffer *eb_root, u64 time_seq)
1113 struct tree_mod_elem *tm;
1114 struct tree_mod_elem *found = NULL;
1115 u64 root_logical = eb_root->start;
1122 * the very last operation that's logged for a root is the replacement
1123 * operation (if it is replaced at all). this has the index of the *new*
1124 * root, making it the very first operation that's logged for this root.
1127 tm = tree_mod_log_search_oldest(fs_info, root_logical,
1132 * if there are no tree operation for the oldest root, we simply
1133 * return it. this should only happen if that (old) root is at
1140 * if there's an operation that's not a root replacement, we
1141 * found the oldest version of our root. normally, we'll find a
1142 * MOD_LOG_KEY_REMOVE_WHILE_FREEING operation here.
1144 if (tm->op != MOD_LOG_ROOT_REPLACE)
1148 root_logical = tm->old_root.logical;
1152 /* if there's no old root to return, return what we found instead */
1160 * tm is a pointer to the first operation to rewind within eb. then, all
1161 * previous operations will be rewinded (until we reach something older than
1165 __tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct extent_buffer *eb,
1166 u64 time_seq, struct tree_mod_elem *first_tm)
1169 struct rb_node *next;
1170 struct tree_mod_elem *tm = first_tm;
1171 unsigned long o_dst;
1172 unsigned long o_src;
1173 unsigned long p_size = sizeof(struct btrfs_key_ptr);
1175 n = btrfs_header_nritems(eb);
1176 tree_mod_log_read_lock(fs_info);
1177 while (tm && tm->seq >= time_seq) {
1179 * all the operations are recorded with the operator used for
1180 * the modification. as we're going backwards, we do the
1181 * opposite of each operation here.
1184 case MOD_LOG_KEY_REMOVE_WHILE_FREEING:
1185 BUG_ON(tm->slot < n);
1187 case MOD_LOG_KEY_REMOVE_WHILE_MOVING:
1188 case MOD_LOG_KEY_REMOVE:
1189 btrfs_set_node_key(eb, &tm->key, tm->slot);
1190 btrfs_set_node_blockptr(eb, tm->slot, tm->blockptr);
1191 btrfs_set_node_ptr_generation(eb, tm->slot,
1195 case MOD_LOG_KEY_REPLACE:
1196 BUG_ON(tm->slot >= n);
1197 btrfs_set_node_key(eb, &tm->key, tm->slot);
1198 btrfs_set_node_blockptr(eb, tm->slot, tm->blockptr);
1199 btrfs_set_node_ptr_generation(eb, tm->slot,
1202 case MOD_LOG_KEY_ADD:
1203 /* if a move operation is needed it's in the log */
1206 case MOD_LOG_MOVE_KEYS:
1207 o_dst = btrfs_node_key_ptr_offset(tm->slot);
1208 o_src = btrfs_node_key_ptr_offset(tm->move.dst_slot);
1209 memmove_extent_buffer(eb, o_dst, o_src,
1210 tm->move.nr_items * p_size);
1212 case MOD_LOG_ROOT_REPLACE:
1214 * this operation is special. for roots, this must be
1215 * handled explicitly before rewinding.
1216 * for non-roots, this operation may exist if the node
1217 * was a root: root A -> child B; then A gets empty and
1218 * B is promoted to the new root. in the mod log, we'll
1219 * have a root-replace operation for B, a tree block
1220 * that is no root. we simply ignore that operation.
1224 next = rb_next(&tm->node);
1227 tm = container_of(next, struct tree_mod_elem, node);
1228 if (tm->index != first_tm->index)
1231 tree_mod_log_read_unlock(fs_info);
1232 btrfs_set_header_nritems(eb, n);
1236 * Called with eb read locked. If the buffer cannot be rewinded, the same buffer
1237 * is returned. If rewind operations happen, a fresh buffer is returned. The
1238 * returned buffer is always read-locked. If the returned buffer is not the
1239 * input buffer, the lock on the input buffer is released and the input buffer
1240 * is freed (its refcount is decremented).
1242 static struct extent_buffer *
1243 tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct extent_buffer *eb,
1246 struct extent_buffer *eb_rewin;
1247 struct tree_mod_elem *tm;
1252 if (btrfs_header_level(eb) == 0)
1255 tm = tree_mod_log_search(fs_info, eb->start, time_seq);
1259 if (tm->op == MOD_LOG_KEY_REMOVE_WHILE_FREEING) {
1260 BUG_ON(tm->slot != 0);
1261 eb_rewin = alloc_dummy_extent_buffer(eb->start,
1262 fs_info->tree_root->nodesize);
1264 btrfs_set_header_bytenr(eb_rewin, eb->start);
1265 btrfs_set_header_backref_rev(eb_rewin,
1266 btrfs_header_backref_rev(eb));
1267 btrfs_set_header_owner(eb_rewin, btrfs_header_owner(eb));
1268 btrfs_set_header_level(eb_rewin, btrfs_header_level(eb));
1270 eb_rewin = btrfs_clone_extent_buffer(eb);
1274 extent_buffer_get(eb_rewin);
1275 btrfs_tree_read_unlock(eb);
1276 free_extent_buffer(eb);
1278 extent_buffer_get(eb_rewin);
1279 btrfs_tree_read_lock(eb_rewin);
1280 __tree_mod_log_rewind(fs_info, eb_rewin, time_seq, tm);
1281 WARN_ON(btrfs_header_nritems(eb_rewin) >
1282 BTRFS_NODEPTRS_PER_BLOCK(fs_info->tree_root));
1288 * get_old_root() rewinds the state of @root's root node to the given @time_seq
1289 * value. If there are no changes, the current root->root_node is returned. If
1290 * anything changed in between, there's a fresh buffer allocated on which the
1291 * rewind operations are done. In any case, the returned buffer is read locked.
1292 * Returns NULL on error (with no locks held).
1294 static inline struct extent_buffer *
1295 get_old_root(struct btrfs_root *root, u64 time_seq)
1297 struct tree_mod_elem *tm;
1298 struct extent_buffer *eb = NULL;
1299 struct extent_buffer *eb_root;
1300 struct extent_buffer *old;
1301 struct tree_mod_root *old_root = NULL;
1302 u64 old_generation = 0;
1306 eb_root = btrfs_read_lock_root_node(root);
1307 tm = __tree_mod_log_oldest_root(root->fs_info, eb_root, time_seq);
1311 if (tm->op == MOD_LOG_ROOT_REPLACE) {
1312 old_root = &tm->old_root;
1313 old_generation = tm->generation;
1314 logical = old_root->logical;
1316 logical = eb_root->start;
1319 tm = tree_mod_log_search(root->fs_info, logical, time_seq);
1320 if (old_root && tm && tm->op != MOD_LOG_KEY_REMOVE_WHILE_FREEING) {
1321 btrfs_tree_read_unlock(eb_root);
1322 free_extent_buffer(eb_root);
1323 blocksize = btrfs_level_size(root, old_root->level);
1324 old = read_tree_block(root, logical, blocksize, 0);
1325 if (!old || !extent_buffer_uptodate(old)) {
1326 free_extent_buffer(old);
1327 pr_warn("btrfs: failed to read tree block %llu from get_old_root\n",
1331 eb = btrfs_clone_extent_buffer(old);
1332 free_extent_buffer(old);
1334 } else if (old_root) {
1335 btrfs_tree_read_unlock(eb_root);
1336 free_extent_buffer(eb_root);
1337 eb = alloc_dummy_extent_buffer(logical, root->nodesize);
1339 eb = btrfs_clone_extent_buffer(eb_root);
1340 btrfs_tree_read_unlock(eb_root);
1341 free_extent_buffer(eb_root);
1346 extent_buffer_get(eb);
1347 btrfs_tree_read_lock(eb);
1349 btrfs_set_header_bytenr(eb, eb->start);
1350 btrfs_set_header_backref_rev(eb, BTRFS_MIXED_BACKREF_REV);
1351 btrfs_set_header_owner(eb, btrfs_header_owner(eb_root));
1352 btrfs_set_header_level(eb, old_root->level);
1353 btrfs_set_header_generation(eb, old_generation);
1356 __tree_mod_log_rewind(root->fs_info, eb, time_seq, tm);
1358 WARN_ON(btrfs_header_level(eb) != 0);
1359 WARN_ON(btrfs_header_nritems(eb) > BTRFS_NODEPTRS_PER_BLOCK(root));
1364 int btrfs_old_root_level(struct btrfs_root *root, u64 time_seq)
1366 struct tree_mod_elem *tm;
1368 struct extent_buffer *eb_root = btrfs_root_node(root);
1370 tm = __tree_mod_log_oldest_root(root->fs_info, eb_root, time_seq);
1371 if (tm && tm->op == MOD_LOG_ROOT_REPLACE) {
1372 level = tm->old_root.level;
1374 level = btrfs_header_level(eb_root);
1376 free_extent_buffer(eb_root);
1381 static inline int should_cow_block(struct btrfs_trans_handle *trans,
1382 struct btrfs_root *root,
1383 struct extent_buffer *buf)
1385 /* ensure we can see the force_cow */
1389 * We do not need to cow a block if
1390 * 1) this block is not created or changed in this transaction;
1391 * 2) this block does not belong to TREE_RELOC tree;
1392 * 3) the root is not forced COW.
1394 * What is forced COW:
1395 * when we create snapshot during commiting the transaction,
1396 * after we've finished coping src root, we must COW the shared
1397 * block to ensure the metadata consistency.
1399 if (btrfs_header_generation(buf) == trans->transid &&
1400 !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN) &&
1401 !(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID &&
1402 btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)) &&
1409 * cows a single block, see __btrfs_cow_block for the real work.
1410 * This version of it has extra checks so that a block isn't cow'd more than
1411 * once per transaction, as long as it hasn't been written yet
1413 noinline int btrfs_cow_block(struct btrfs_trans_handle *trans,
1414 struct btrfs_root *root, struct extent_buffer *buf,
1415 struct extent_buffer *parent, int parent_slot,
1416 struct extent_buffer **cow_ret)
1421 if (trans->transaction != root->fs_info->running_transaction)
1422 WARN(1, KERN_CRIT "trans %llu running %llu\n",
1423 (unsigned long long)trans->transid,
1424 (unsigned long long)
1425 root->fs_info->running_transaction->transid);
1427 if (trans->transid != root->fs_info->generation)
1428 WARN(1, KERN_CRIT "trans %llu running %llu\n",
1429 (unsigned long long)trans->transid,
1430 (unsigned long long)root->fs_info->generation);
1432 if (!should_cow_block(trans, root, buf)) {
1437 search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1);
1440 btrfs_set_lock_blocking(parent);
1441 btrfs_set_lock_blocking(buf);
1443 ret = __btrfs_cow_block(trans, root, buf, parent,
1444 parent_slot, cow_ret, search_start, 0);
1446 trace_btrfs_cow_block(root, buf, *cow_ret);
1452 * helper function for defrag to decide if two blocks pointed to by a
1453 * node are actually close by
1455 static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
1457 if (blocknr < other && other - (blocknr + blocksize) < 32768)
1459 if (blocknr > other && blocknr - (other + blocksize) < 32768)
1465 * compare two keys in a memcmp fashion
1467 static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
1469 struct btrfs_key k1;
1471 btrfs_disk_key_to_cpu(&k1, disk);
1473 return btrfs_comp_cpu_keys(&k1, k2);
1477 * same as comp_keys only with two btrfs_key's
1479 int btrfs_comp_cpu_keys(struct btrfs_key *k1, struct btrfs_key *k2)
1481 if (k1->objectid > k2->objectid)
1483 if (k1->objectid < k2->objectid)
1485 if (k1->type > k2->type)
1487 if (k1->type < k2->type)
1489 if (k1->offset > k2->offset)
1491 if (k1->offset < k2->offset)
1497 * this is used by the defrag code to go through all the
1498 * leaves pointed to by a node and reallocate them so that
1499 * disk order is close to key order
1501 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
1502 struct btrfs_root *root, struct extent_buffer *parent,
1503 int start_slot, u64 *last_ret,
1504 struct btrfs_key *progress)
1506 struct extent_buffer *cur;
1509 u64 search_start = *last_ret;
1519 int progress_passed = 0;
1520 struct btrfs_disk_key disk_key;
1522 parent_level = btrfs_header_level(parent);
1524 WARN_ON(trans->transaction != root->fs_info->running_transaction);
1525 WARN_ON(trans->transid != root->fs_info->generation);
1527 parent_nritems = btrfs_header_nritems(parent);
1528 blocksize = btrfs_level_size(root, parent_level - 1);
1529 end_slot = parent_nritems;
1531 if (parent_nritems == 1)
1534 btrfs_set_lock_blocking(parent);
1536 for (i = start_slot; i < end_slot; i++) {
1539 btrfs_node_key(parent, &disk_key, i);
1540 if (!progress_passed && comp_keys(&disk_key, progress) < 0)
1543 progress_passed = 1;
1544 blocknr = btrfs_node_blockptr(parent, i);
1545 gen = btrfs_node_ptr_generation(parent, i);
1546 if (last_block == 0)
1547 last_block = blocknr;
1550 other = btrfs_node_blockptr(parent, i - 1);
1551 close = close_blocks(blocknr, other, blocksize);
1553 if (!close && i < end_slot - 2) {
1554 other = btrfs_node_blockptr(parent, i + 1);
1555 close = close_blocks(blocknr, other, blocksize);
1558 last_block = blocknr;
1562 cur = btrfs_find_tree_block(root, blocknr, blocksize);
1564 uptodate = btrfs_buffer_uptodate(cur, gen, 0);
1567 if (!cur || !uptodate) {
1569 cur = read_tree_block(root, blocknr,
1571 if (!cur || !extent_buffer_uptodate(cur)) {
1572 free_extent_buffer(cur);
1575 } else if (!uptodate) {
1576 err = btrfs_read_buffer(cur, gen);
1578 free_extent_buffer(cur);
1583 if (search_start == 0)
1584 search_start = last_block;
1586 btrfs_tree_lock(cur);
1587 btrfs_set_lock_blocking(cur);
1588 err = __btrfs_cow_block(trans, root, cur, parent, i,
1591 (end_slot - i) * blocksize));
1593 btrfs_tree_unlock(cur);
1594 free_extent_buffer(cur);
1597 search_start = cur->start;
1598 last_block = cur->start;
1599 *last_ret = search_start;
1600 btrfs_tree_unlock(cur);
1601 free_extent_buffer(cur);
1607 * The leaf data grows from end-to-front in the node.
1608 * this returns the address of the start of the last item,
1609 * which is the stop of the leaf data stack
1611 static inline unsigned int leaf_data_end(struct btrfs_root *root,
1612 struct extent_buffer *leaf)
1614 u32 nr = btrfs_header_nritems(leaf);
1616 return BTRFS_LEAF_DATA_SIZE(root);
1617 return btrfs_item_offset_nr(leaf, nr - 1);
1622 * search for key in the extent_buffer. The items start at offset p,
1623 * and they are item_size apart. There are 'max' items in p.
1625 * the slot in the array is returned via slot, and it points to
1626 * the place where you would insert key if it is not found in
1629 * slot may point to max if the key is bigger than all of the keys
1631 static noinline int generic_bin_search(struct extent_buffer *eb,
1633 int item_size, struct btrfs_key *key,
1640 struct btrfs_disk_key *tmp = NULL;
1641 struct btrfs_disk_key unaligned;
1642 unsigned long offset;
1644 unsigned long map_start = 0;
1645 unsigned long map_len = 0;
1648 while (low < high) {
1649 mid = (low + high) / 2;
1650 offset = p + mid * item_size;
1652 if (!kaddr || offset < map_start ||
1653 (offset + sizeof(struct btrfs_disk_key)) >
1654 map_start + map_len) {
1656 err = map_private_extent_buffer(eb, offset,
1657 sizeof(struct btrfs_disk_key),
1658 &kaddr, &map_start, &map_len);
1661 tmp = (struct btrfs_disk_key *)(kaddr + offset -
1664 read_extent_buffer(eb, &unaligned,
1665 offset, sizeof(unaligned));
1670 tmp = (struct btrfs_disk_key *)(kaddr + offset -
1673 ret = comp_keys(tmp, key);
1689 * simple bin_search frontend that does the right thing for
1692 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
1693 int level, int *slot)
1696 return generic_bin_search(eb,
1697 offsetof(struct btrfs_leaf, items),
1698 sizeof(struct btrfs_item),
1699 key, btrfs_header_nritems(eb),
1702 return generic_bin_search(eb,
1703 offsetof(struct btrfs_node, ptrs),
1704 sizeof(struct btrfs_key_ptr),
1705 key, btrfs_header_nritems(eb),
1709 int btrfs_bin_search(struct extent_buffer *eb, struct btrfs_key *key,
1710 int level, int *slot)
1712 return bin_search(eb, key, level, slot);
1715 static void root_add_used(struct btrfs_root *root, u32 size)
1717 spin_lock(&root->accounting_lock);
1718 btrfs_set_root_used(&root->root_item,
1719 btrfs_root_used(&root->root_item) + size);
1720 spin_unlock(&root->accounting_lock);
1723 static void root_sub_used(struct btrfs_root *root, u32 size)
1725 spin_lock(&root->accounting_lock);
1726 btrfs_set_root_used(&root->root_item,
1727 btrfs_root_used(&root->root_item) - size);
1728 spin_unlock(&root->accounting_lock);
1731 /* given a node and slot number, this reads the blocks it points to. The
1732 * extent buffer is returned with a reference taken (but unlocked).
1733 * NULL is returned on error.
1735 static noinline struct extent_buffer *read_node_slot(struct btrfs_root *root,
1736 struct extent_buffer *parent, int slot)
1738 int level = btrfs_header_level(parent);
1739 struct extent_buffer *eb;
1743 if (slot >= btrfs_header_nritems(parent))
1748 eb = read_tree_block(root, btrfs_node_blockptr(parent, slot),
1749 btrfs_level_size(root, level - 1),
1750 btrfs_node_ptr_generation(parent, slot));
1751 if (eb && !extent_buffer_uptodate(eb)) {
1752 free_extent_buffer(eb);
1760 * node level balancing, used to make sure nodes are in proper order for
1761 * item deletion. We balance from the top down, so we have to make sure
1762 * that a deletion won't leave an node completely empty later on.
1764 static noinline int balance_level(struct btrfs_trans_handle *trans,
1765 struct btrfs_root *root,
1766 struct btrfs_path *path, int level)
1768 struct extent_buffer *right = NULL;
1769 struct extent_buffer *mid;
1770 struct extent_buffer *left = NULL;
1771 struct extent_buffer *parent = NULL;
1775 int orig_slot = path->slots[level];
1781 mid = path->nodes[level];
1783 WARN_ON(path->locks[level] != BTRFS_WRITE_LOCK &&
1784 path->locks[level] != BTRFS_WRITE_LOCK_BLOCKING);
1785 WARN_ON(btrfs_header_generation(mid) != trans->transid);
1787 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
1789 if (level < BTRFS_MAX_LEVEL - 1) {
1790 parent = path->nodes[level + 1];
1791 pslot = path->slots[level + 1];
1795 * deal with the case where there is only one pointer in the root
1796 * by promoting the node below to a root
1799 struct extent_buffer *child;
1801 if (btrfs_header_nritems(mid) != 1)
1804 /* promote the child to a root */
1805 child = read_node_slot(root, mid, 0);
1808 btrfs_std_error(root->fs_info, ret);
1812 btrfs_tree_lock(child);
1813 btrfs_set_lock_blocking(child);
1814 ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
1816 btrfs_tree_unlock(child);
1817 free_extent_buffer(child);
1821 tree_mod_log_set_root_pointer(root, child, 1);
1822 rcu_assign_pointer(root->node, child);
1824 add_root_to_dirty_list(root);
1825 btrfs_tree_unlock(child);
1827 path->locks[level] = 0;
1828 path->nodes[level] = NULL;
1829 clean_tree_block(trans, root, mid);
1830 btrfs_tree_unlock(mid);
1831 /* once for the path */
1832 free_extent_buffer(mid);
1834 root_sub_used(root, mid->len);
1835 btrfs_free_tree_block(trans, root, mid, 0, 1);
1836 /* once for the root ptr */
1837 free_extent_buffer_stale(mid);
1840 if (btrfs_header_nritems(mid) >
1841 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
1844 left = read_node_slot(root, parent, pslot - 1);
1846 btrfs_tree_lock(left);
1847 btrfs_set_lock_blocking(left);
1848 wret = btrfs_cow_block(trans, root, left,
1849 parent, pslot - 1, &left);
1855 right = read_node_slot(root, parent, pslot + 1);
1857 btrfs_tree_lock(right);
1858 btrfs_set_lock_blocking(right);
1859 wret = btrfs_cow_block(trans, root, right,
1860 parent, pslot + 1, &right);
1867 /* first, try to make some room in the middle buffer */
1869 orig_slot += btrfs_header_nritems(left);
1870 wret = push_node_left(trans, root, left, mid, 1);
1876 * then try to empty the right most buffer into the middle
1879 wret = push_node_left(trans, root, mid, right, 1);
1880 if (wret < 0 && wret != -ENOSPC)
1882 if (btrfs_header_nritems(right) == 0) {
1883 clean_tree_block(trans, root, right);
1884 btrfs_tree_unlock(right);
1885 del_ptr(root, path, level + 1, pslot + 1);
1886 root_sub_used(root, right->len);
1887 btrfs_free_tree_block(trans, root, right, 0, 1);
1888 free_extent_buffer_stale(right);
1891 struct btrfs_disk_key right_key;
1892 btrfs_node_key(right, &right_key, 0);
1893 tree_mod_log_set_node_key(root->fs_info, parent,
1895 btrfs_set_node_key(parent, &right_key, pslot + 1);
1896 btrfs_mark_buffer_dirty(parent);
1899 if (btrfs_header_nritems(mid) == 1) {
1901 * we're not allowed to leave a node with one item in the
1902 * tree during a delete. A deletion from lower in the tree
1903 * could try to delete the only pointer in this node.
1904 * So, pull some keys from the left.
1905 * There has to be a left pointer at this point because
1906 * otherwise we would have pulled some pointers from the
1911 btrfs_std_error(root->fs_info, ret);
1914 wret = balance_node_right(trans, root, mid, left);
1920 wret = push_node_left(trans, root, left, mid, 1);
1926 if (btrfs_header_nritems(mid) == 0) {
1927 clean_tree_block(trans, root, mid);
1928 btrfs_tree_unlock(mid);
1929 del_ptr(root, path, level + 1, pslot);
1930 root_sub_used(root, mid->len);
1931 btrfs_free_tree_block(trans, root, mid, 0, 1);
1932 free_extent_buffer_stale(mid);
1935 /* update the parent key to reflect our changes */
1936 struct btrfs_disk_key mid_key;
1937 btrfs_node_key(mid, &mid_key, 0);
1938 tree_mod_log_set_node_key(root->fs_info, parent,
1940 btrfs_set_node_key(parent, &mid_key, pslot);
1941 btrfs_mark_buffer_dirty(parent);
1944 /* update the path */
1946 if (btrfs_header_nritems(left) > orig_slot) {
1947 extent_buffer_get(left);
1948 /* left was locked after cow */
1949 path->nodes[level] = left;
1950 path->slots[level + 1] -= 1;
1951 path->slots[level] = orig_slot;
1953 btrfs_tree_unlock(mid);
1954 free_extent_buffer(mid);
1957 orig_slot -= btrfs_header_nritems(left);
1958 path->slots[level] = orig_slot;
1961 /* double check we haven't messed things up */
1963 btrfs_node_blockptr(path->nodes[level], path->slots[level]))
1967 btrfs_tree_unlock(right);
1968 free_extent_buffer(right);
1971 if (path->nodes[level] != left)
1972 btrfs_tree_unlock(left);
1973 free_extent_buffer(left);
1978 /* Node balancing for insertion. Here we only split or push nodes around
1979 * when they are completely full. This is also done top down, so we
1980 * have to be pessimistic.
1982 static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
1983 struct btrfs_root *root,
1984 struct btrfs_path *path, int level)
1986 struct extent_buffer *right = NULL;
1987 struct extent_buffer *mid;
1988 struct extent_buffer *left = NULL;
1989 struct extent_buffer *parent = NULL;
1993 int orig_slot = path->slots[level];
1998 mid = path->nodes[level];
1999 WARN_ON(btrfs_header_generation(mid) != trans->transid);
2001 if (level < BTRFS_MAX_LEVEL - 1) {
2002 parent = path->nodes[level + 1];
2003 pslot = path->slots[level + 1];
2009 left = read_node_slot(root, parent, pslot - 1);
2011 /* first, try to make some room in the middle buffer */
2015 btrfs_tree_lock(left);
2016 btrfs_set_lock_blocking(left);
2018 left_nr = btrfs_header_nritems(left);
2019 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
2022 ret = btrfs_cow_block(trans, root, left, parent,
2027 wret = push_node_left(trans, root,
2034 struct btrfs_disk_key disk_key;
2035 orig_slot += left_nr;
2036 btrfs_node_key(mid, &disk_key, 0);
2037 tree_mod_log_set_node_key(root->fs_info, parent,
2039 btrfs_set_node_key(parent, &disk_key, pslot);
2040 btrfs_mark_buffer_dirty(parent);
2041 if (btrfs_header_nritems(left) > orig_slot) {
2042 path->nodes[level] = left;
2043 path->slots[level + 1] -= 1;
2044 path->slots[level] = orig_slot;
2045 btrfs_tree_unlock(mid);
2046 free_extent_buffer(mid);
2049 btrfs_header_nritems(left);
2050 path->slots[level] = orig_slot;
2051 btrfs_tree_unlock(left);
2052 free_extent_buffer(left);
2056 btrfs_tree_unlock(left);
2057 free_extent_buffer(left);
2059 right = read_node_slot(root, parent, pslot + 1);
2062 * then try to empty the right most buffer into the middle
2067 btrfs_tree_lock(right);
2068 btrfs_set_lock_blocking(right);
2070 right_nr = btrfs_header_nritems(right);
2071 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
2074 ret = btrfs_cow_block(trans, root, right,
2080 wret = balance_node_right(trans, root,
2087 struct btrfs_disk_key disk_key;
2089 btrfs_node_key(right, &disk_key, 0);
2090 tree_mod_log_set_node_key(root->fs_info, parent,
2092 btrfs_set_node_key(parent, &disk_key, pslot + 1);
2093 btrfs_mark_buffer_dirty(parent);
2095 if (btrfs_header_nritems(mid) <= orig_slot) {
2096 path->nodes[level] = right;
2097 path->slots[level + 1] += 1;
2098 path->slots[level] = orig_slot -
2099 btrfs_header_nritems(mid);
2100 btrfs_tree_unlock(mid);
2101 free_extent_buffer(mid);
2103 btrfs_tree_unlock(right);
2104 free_extent_buffer(right);
2108 btrfs_tree_unlock(right);
2109 free_extent_buffer(right);
2115 * readahead one full node of leaves, finding things that are close
2116 * to the block in 'slot', and triggering ra on them.
2118 static void reada_for_search(struct btrfs_root *root,
2119 struct btrfs_path *path,
2120 int level, int slot, u64 objectid)
2122 struct extent_buffer *node;
2123 struct btrfs_disk_key disk_key;
2129 int direction = path->reada;
2130 struct extent_buffer *eb;
2138 if (!path->nodes[level])
2141 node = path->nodes[level];
2143 search = btrfs_node_blockptr(node, slot);
2144 blocksize = btrfs_level_size(root, level - 1);
2145 eb = btrfs_find_tree_block(root, search, blocksize);
2147 free_extent_buffer(eb);
2153 nritems = btrfs_header_nritems(node);
2157 if (direction < 0) {
2161 } else if (direction > 0) {
2166 if (path->reada < 0 && objectid) {
2167 btrfs_node_key(node, &disk_key, nr);
2168 if (btrfs_disk_key_objectid(&disk_key) != objectid)
2171 search = btrfs_node_blockptr(node, nr);
2172 if ((search <= target && target - search <= 65536) ||
2173 (search > target && search - target <= 65536)) {
2174 gen = btrfs_node_ptr_generation(node, nr);
2175 readahead_tree_block(root, search, blocksize, gen);
2179 if ((nread > 65536 || nscan > 32))
2184 static noinline void reada_for_balance(struct btrfs_root *root,
2185 struct btrfs_path *path, int level)
2189 struct extent_buffer *parent;
2190 struct extent_buffer *eb;
2196 parent = path->nodes[level + 1];
2200 nritems = btrfs_header_nritems(parent);
2201 slot = path->slots[level + 1];
2202 blocksize = btrfs_level_size(root, level);
2205 block1 = btrfs_node_blockptr(parent, slot - 1);
2206 gen = btrfs_node_ptr_generation(parent, slot - 1);
2207 eb = btrfs_find_tree_block(root, block1, blocksize);
2209 * if we get -eagain from btrfs_buffer_uptodate, we
2210 * don't want to return eagain here. That will loop
2213 if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0)
2215 free_extent_buffer(eb);
2217 if (slot + 1 < nritems) {
2218 block2 = btrfs_node_blockptr(parent, slot + 1);
2219 gen = btrfs_node_ptr_generation(parent, slot + 1);
2220 eb = btrfs_find_tree_block(root, block2, blocksize);
2221 if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0)
2223 free_extent_buffer(eb);
2227 readahead_tree_block(root, block1, blocksize, 0);
2229 readahead_tree_block(root, block2, blocksize, 0);
2234 * when we walk down the tree, it is usually safe to unlock the higher layers
2235 * in the tree. The exceptions are when our path goes through slot 0, because
2236 * operations on the tree might require changing key pointers higher up in the
2239 * callers might also have set path->keep_locks, which tells this code to keep
2240 * the lock if the path points to the last slot in the block. This is part of
2241 * walking through the tree, and selecting the next slot in the higher block.
2243 * lowest_unlock sets the lowest level in the tree we're allowed to unlock. so
2244 * if lowest_unlock is 1, level 0 won't be unlocked
2246 static noinline void unlock_up(struct btrfs_path *path, int level,
2247 int lowest_unlock, int min_write_lock_level,
2248 int *write_lock_level)
2251 int skip_level = level;
2253 struct extent_buffer *t;
2255 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
2256 if (!path->nodes[i])
2258 if (!path->locks[i])
2260 if (!no_skips && path->slots[i] == 0) {
2264 if (!no_skips && path->keep_locks) {
2267 nritems = btrfs_header_nritems(t);
2268 if (nritems < 1 || path->slots[i] >= nritems - 1) {
2273 if (skip_level < i && i >= lowest_unlock)
2277 if (i >= lowest_unlock && i > skip_level && path->locks[i]) {
2278 btrfs_tree_unlock_rw(t, path->locks[i]);
2280 if (write_lock_level &&
2281 i > min_write_lock_level &&
2282 i <= *write_lock_level) {
2283 *write_lock_level = i - 1;
2290 * This releases any locks held in the path starting at level and
2291 * going all the way up to the root.
2293 * btrfs_search_slot will keep the lock held on higher nodes in a few
2294 * corner cases, such as COW of the block at slot zero in the node. This
2295 * ignores those rules, and it should only be called when there are no
2296 * more updates to be done higher up in the tree.
2298 noinline void btrfs_unlock_up_safe(struct btrfs_path *path, int level)
2302 if (path->keep_locks)
2305 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
2306 if (!path->nodes[i])
2308 if (!path->locks[i])
2310 btrfs_tree_unlock_rw(path->nodes[i], path->locks[i]);
2316 * helper function for btrfs_search_slot. The goal is to find a block
2317 * in cache without setting the path to blocking. If we find the block
2318 * we return zero and the path is unchanged.
2320 * If we can't find the block, we set the path blocking and do some
2321 * reada. -EAGAIN is returned and the search must be repeated.
2324 read_block_for_search(struct btrfs_trans_handle *trans,
2325 struct btrfs_root *root, struct btrfs_path *p,
2326 struct extent_buffer **eb_ret, int level, int slot,
2327 struct btrfs_key *key, u64 time_seq)
2332 struct extent_buffer *b = *eb_ret;
2333 struct extent_buffer *tmp;
2336 blocknr = btrfs_node_blockptr(b, slot);
2337 gen = btrfs_node_ptr_generation(b, slot);
2338 blocksize = btrfs_level_size(root, level - 1);
2340 tmp = btrfs_find_tree_block(root, blocknr, blocksize);
2342 /* first we do an atomic uptodate check */
2343 if (btrfs_buffer_uptodate(tmp, gen, 1) > 0) {
2348 /* the pages were up to date, but we failed
2349 * the generation number check. Do a full
2350 * read for the generation number that is correct.
2351 * We must do this without dropping locks so
2352 * we can trust our generation number
2354 btrfs_set_path_blocking(p);
2356 /* now we're allowed to do a blocking uptodate check */
2357 ret = btrfs_read_buffer(tmp, gen);
2362 free_extent_buffer(tmp);
2363 btrfs_release_path(p);
2368 * reduce lock contention at high levels
2369 * of the btree by dropping locks before
2370 * we read. Don't release the lock on the current
2371 * level because we need to walk this node to figure
2372 * out which blocks to read.
2374 btrfs_unlock_up_safe(p, level + 1);
2375 btrfs_set_path_blocking(p);
2377 free_extent_buffer(tmp);
2379 reada_for_search(root, p, level, slot, key->objectid);
2381 btrfs_release_path(p);
2384 tmp = read_tree_block(root, blocknr, blocksize, 0);
2387 * If the read above didn't mark this buffer up to date,
2388 * it will never end up being up to date. Set ret to EIO now
2389 * and give up so that our caller doesn't loop forever
2392 if (!btrfs_buffer_uptodate(tmp, 0, 0))
2394 free_extent_buffer(tmp);
2400 * helper function for btrfs_search_slot. This does all of the checks
2401 * for node-level blocks and does any balancing required based on
2404 * If no extra work was required, zero is returned. If we had to
2405 * drop the path, -EAGAIN is returned and btrfs_search_slot must
2409 setup_nodes_for_search(struct btrfs_trans_handle *trans,
2410 struct btrfs_root *root, struct btrfs_path *p,
2411 struct extent_buffer *b, int level, int ins_len,
2412 int *write_lock_level)
2415 if ((p->search_for_split || ins_len > 0) && btrfs_header_nritems(b) >=
2416 BTRFS_NODEPTRS_PER_BLOCK(root) - 3) {
2419 if (*write_lock_level < level + 1) {
2420 *write_lock_level = level + 1;
2421 btrfs_release_path(p);
2425 btrfs_set_path_blocking(p);
2426 reada_for_balance(root, p, level);
2427 sret = split_node(trans, root, p, level);
2428 btrfs_clear_path_blocking(p, NULL, 0);
2435 b = p->nodes[level];
2436 } else if (ins_len < 0 && btrfs_header_nritems(b) <
2437 BTRFS_NODEPTRS_PER_BLOCK(root) / 2) {
2440 if (*write_lock_level < level + 1) {
2441 *write_lock_level = level + 1;
2442 btrfs_release_path(p);
2446 btrfs_set_path_blocking(p);
2447 reada_for_balance(root, p, level);
2448 sret = balance_level(trans, root, p, level);
2449 btrfs_clear_path_blocking(p, NULL, 0);
2455 b = p->nodes[level];
2457 btrfs_release_path(p);
2460 BUG_ON(btrfs_header_nritems(b) == 1);
2471 * look for key in the tree. path is filled in with nodes along the way
2472 * if key is found, we return zero and you can find the item in the leaf
2473 * level of the path (level 0)
2475 * If the key isn't found, the path points to the slot where it should
2476 * be inserted, and 1 is returned. If there are other errors during the
2477 * search a negative error number is returned.
2479 * if ins_len > 0, nodes and leaves will be split as we walk down the
2480 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
2483 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
2484 *root, struct btrfs_key *key, struct btrfs_path *p, int
2487 struct extent_buffer *b;
2492 int lowest_unlock = 1;
2494 /* everything at write_lock_level or lower must be write locked */
2495 int write_lock_level = 0;
2496 u8 lowest_level = 0;
2497 int min_write_lock_level;
2499 lowest_level = p->lowest_level;
2500 WARN_ON(lowest_level && ins_len > 0);
2501 WARN_ON(p->nodes[0] != NULL);
2506 /* when we are removing items, we might have to go up to level
2507 * two as we update tree pointers Make sure we keep write
2508 * for those levels as well
2510 write_lock_level = 2;
2511 } else if (ins_len > 0) {
2513 * for inserting items, make sure we have a write lock on
2514 * level 1 so we can update keys
2516 write_lock_level = 1;
2520 write_lock_level = -1;
2522 if (cow && (p->keep_locks || p->lowest_level))
2523 write_lock_level = BTRFS_MAX_LEVEL;
2525 min_write_lock_level = write_lock_level;
2529 * we try very hard to do read locks on the root
2531 root_lock = BTRFS_READ_LOCK;
2533 if (p->search_commit_root) {
2535 * the commit roots are read only
2536 * so we always do read locks
2538 b = root->commit_root;
2539 extent_buffer_get(b);
2540 level = btrfs_header_level(b);
2541 if (!p->skip_locking)
2542 btrfs_tree_read_lock(b);
2544 if (p->skip_locking) {
2545 b = btrfs_root_node(root);
2546 level = btrfs_header_level(b);
2548 /* we don't know the level of the root node
2549 * until we actually have it read locked
2551 b = btrfs_read_lock_root_node(root);
2552 level = btrfs_header_level(b);
2553 if (level <= write_lock_level) {
2554 /* whoops, must trade for write lock */
2555 btrfs_tree_read_unlock(b);
2556 free_extent_buffer(b);
2557 b = btrfs_lock_root_node(root);
2558 root_lock = BTRFS_WRITE_LOCK;
2560 /* the level might have changed, check again */
2561 level = btrfs_header_level(b);
2565 p->nodes[level] = b;
2566 if (!p->skip_locking)
2567 p->locks[level] = root_lock;
2570 level = btrfs_header_level(b);
2573 * setup the path here so we can release it under lock
2574 * contention with the cow code
2578 * if we don't really need to cow this block
2579 * then we don't want to set the path blocking,
2580 * so we test it here
2582 if (!should_cow_block(trans, root, b))
2585 btrfs_set_path_blocking(p);
2588 * must have write locks on this node and the
2591 if (level > write_lock_level ||
2592 (level + 1 > write_lock_level &&
2593 level + 1 < BTRFS_MAX_LEVEL &&
2594 p->nodes[level + 1])) {
2595 write_lock_level = level + 1;
2596 btrfs_release_path(p);
2600 err = btrfs_cow_block(trans, root, b,
2601 p->nodes[level + 1],
2602 p->slots[level + 1], &b);
2609 BUG_ON(!cow && ins_len);
2611 p->nodes[level] = b;
2612 btrfs_clear_path_blocking(p, NULL, 0);
2615 * we have a lock on b and as long as we aren't changing
2616 * the tree, there is no way to for the items in b to change.
2617 * It is safe to drop the lock on our parent before we
2618 * go through the expensive btree search on b.
2620 * If cow is true, then we might be changing slot zero,
2621 * which may require changing the parent. So, we can't
2622 * drop the lock until after we know which slot we're
2626 btrfs_unlock_up_safe(p, level + 1);
2628 ret = bin_search(b, key, level, &slot);
2632 if (ret && slot > 0) {
2636 p->slots[level] = slot;
2637 err = setup_nodes_for_search(trans, root, p, b, level,
2638 ins_len, &write_lock_level);
2645 b = p->nodes[level];
2646 slot = p->slots[level];
2649 * slot 0 is special, if we change the key
2650 * we have to update the parent pointer
2651 * which means we must have a write lock
2654 if (slot == 0 && cow &&
2655 write_lock_level < level + 1) {
2656 write_lock_level = level + 1;
2657 btrfs_release_path(p);
2661 unlock_up(p, level, lowest_unlock,
2662 min_write_lock_level, &write_lock_level);
2664 if (level == lowest_level) {
2670 err = read_block_for_search(trans, root, p,
2671 &b, level, slot, key, 0);
2679 if (!p->skip_locking) {
2680 level = btrfs_header_level(b);
2681 if (level <= write_lock_level) {
2682 err = btrfs_try_tree_write_lock(b);
2684 btrfs_set_path_blocking(p);
2686 btrfs_clear_path_blocking(p, b,
2689 p->locks[level] = BTRFS_WRITE_LOCK;
2691 err = btrfs_try_tree_read_lock(b);
2693 btrfs_set_path_blocking(p);
2694 btrfs_tree_read_lock(b);
2695 btrfs_clear_path_blocking(p, b,
2698 p->locks[level] = BTRFS_READ_LOCK;
2700 p->nodes[level] = b;
2703 p->slots[level] = slot;
2705 btrfs_leaf_free_space(root, b) < ins_len) {
2706 if (write_lock_level < 1) {
2707 write_lock_level = 1;
2708 btrfs_release_path(p);
2712 btrfs_set_path_blocking(p);
2713 err = split_leaf(trans, root, key,
2714 p, ins_len, ret == 0);
2715 btrfs_clear_path_blocking(p, NULL, 0);
2723 if (!p->search_for_split)
2724 unlock_up(p, level, lowest_unlock,
2725 min_write_lock_level, &write_lock_level);
2732 * we don't really know what they plan on doing with the path
2733 * from here on, so for now just mark it as blocking
2735 if (!p->leave_spinning)
2736 btrfs_set_path_blocking(p);
2738 btrfs_release_path(p);
2743 * Like btrfs_search_slot, this looks for a key in the given tree. It uses the
2744 * current state of the tree together with the operations recorded in the tree
2745 * modification log to search for the key in a previous version of this tree, as
2746 * denoted by the time_seq parameter.
2748 * Naturally, there is no support for insert, delete or cow operations.
2750 * The resulting path and return value will be set up as if we called
2751 * btrfs_search_slot at that point in time with ins_len and cow both set to 0.
2753 int btrfs_search_old_slot(struct btrfs_root *root, struct btrfs_key *key,
2754 struct btrfs_path *p, u64 time_seq)
2756 struct extent_buffer *b;
2761 int lowest_unlock = 1;
2762 u8 lowest_level = 0;
2764 lowest_level = p->lowest_level;
2765 WARN_ON(p->nodes[0] != NULL);
2767 if (p->search_commit_root) {
2769 return btrfs_search_slot(NULL, root, key, p, 0, 0);
2773 b = get_old_root(root, time_seq);
2774 level = btrfs_header_level(b);
2775 p->locks[level] = BTRFS_READ_LOCK;
2778 level = btrfs_header_level(b);
2779 p->nodes[level] = b;
2780 btrfs_clear_path_blocking(p, NULL, 0);
2783 * we have a lock on b and as long as we aren't changing
2784 * the tree, there is no way to for the items in b to change.
2785 * It is safe to drop the lock on our parent before we
2786 * go through the expensive btree search on b.
2788 btrfs_unlock_up_safe(p, level + 1);
2790 ret = bin_search(b, key, level, &slot);
2794 if (ret && slot > 0) {
2798 p->slots[level] = slot;
2799 unlock_up(p, level, lowest_unlock, 0, NULL);
2801 if (level == lowest_level) {
2807 err = read_block_for_search(NULL, root, p, &b, level,
2808 slot, key, time_seq);
2816 level = btrfs_header_level(b);
2817 err = btrfs_try_tree_read_lock(b);
2819 btrfs_set_path_blocking(p);
2820 btrfs_tree_read_lock(b);
2821 btrfs_clear_path_blocking(p, b,
2824 b = tree_mod_log_rewind(root->fs_info, b, time_seq);
2825 p->locks[level] = BTRFS_READ_LOCK;
2826 p->nodes[level] = b;
2828 p->slots[level] = slot;
2829 unlock_up(p, level, lowest_unlock, 0, NULL);
2835 if (!p->leave_spinning)
2836 btrfs_set_path_blocking(p);
2838 btrfs_release_path(p);
2844 * helper to use instead of search slot if no exact match is needed but
2845 * instead the next or previous item should be returned.
2846 * When find_higher is true, the next higher item is returned, the next lower
2848 * When return_any and find_higher are both true, and no higher item is found,
2849 * return the next lower instead.
2850 * When return_any is true and find_higher is false, and no lower item is found,
2851 * return the next higher instead.
2852 * It returns 0 if any item is found, 1 if none is found (tree empty), and
2855 int btrfs_search_slot_for_read(struct btrfs_root *root,
2856 struct btrfs_key *key, struct btrfs_path *p,
2857 int find_higher, int return_any)
2860 struct extent_buffer *leaf;
2863 ret = btrfs_search_slot(NULL, root, key, p, 0, 0);
2867 * a return value of 1 means the path is at the position where the
2868 * item should be inserted. Normally this is the next bigger item,
2869 * but in case the previous item is the last in a leaf, path points
2870 * to the first free slot in the previous leaf, i.e. at an invalid
2876 if (p->slots[0] >= btrfs_header_nritems(leaf)) {
2877 ret = btrfs_next_leaf(root, p);
2883 * no higher item found, return the next
2888 btrfs_release_path(p);
2892 if (p->slots[0] == 0) {
2893 ret = btrfs_prev_leaf(root, p);
2897 p->slots[0] = btrfs_header_nritems(leaf) - 1;
2903 * no lower item found, return the next
2908 btrfs_release_path(p);
2918 * adjust the pointers going up the tree, starting at level
2919 * making sure the right key of each node is points to 'key'.
2920 * This is used after shifting pointers to the left, so it stops
2921 * fixing up pointers when a given leaf/node is not in slot 0 of the
2925 static void fixup_low_keys(struct btrfs_root *root, struct btrfs_path *path,
2926 struct btrfs_disk_key *key, int level)
2929 struct extent_buffer *t;
2931 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
2932 int tslot = path->slots[i];
2933 if (!path->nodes[i])
2936 tree_mod_log_set_node_key(root->fs_info, t, tslot, 1);
2937 btrfs_set_node_key(t, key, tslot);
2938 btrfs_mark_buffer_dirty(path->nodes[i]);
2947 * This function isn't completely safe. It's the caller's responsibility
2948 * that the new key won't break the order
2950 void btrfs_set_item_key_safe(struct btrfs_root *root, struct btrfs_path *path,
2951 struct btrfs_key *new_key)
2953 struct btrfs_disk_key disk_key;
2954 struct extent_buffer *eb;
2957 eb = path->nodes[0];
2958 slot = path->slots[0];
2960 btrfs_item_key(eb, &disk_key, slot - 1);
2961 BUG_ON(comp_keys(&disk_key, new_key) >= 0);
2963 if (slot < btrfs_header_nritems(eb) - 1) {
2964 btrfs_item_key(eb, &disk_key, slot + 1);
2965 BUG_ON(comp_keys(&disk_key, new_key) <= 0);
2968 btrfs_cpu_key_to_disk(&disk_key, new_key);
2969 btrfs_set_item_key(eb, &disk_key, slot);
2970 btrfs_mark_buffer_dirty(eb);
2972 fixup_low_keys(root, path, &disk_key, 1);
2976 * try to push data from one node into the next node left in the
2979 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
2980 * error, and > 0 if there was no room in the left hand block.
2982 static int push_node_left(struct btrfs_trans_handle *trans,
2983 struct btrfs_root *root, struct extent_buffer *dst,
2984 struct extent_buffer *src, int empty)
2991 src_nritems = btrfs_header_nritems(src);
2992 dst_nritems = btrfs_header_nritems(dst);
2993 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
2994 WARN_ON(btrfs_header_generation(src) != trans->transid);
2995 WARN_ON(btrfs_header_generation(dst) != trans->transid);
2997 if (!empty && src_nritems <= 8)
3000 if (push_items <= 0)
3004 push_items = min(src_nritems, push_items);
3005 if (push_items < src_nritems) {
3006 /* leave at least 8 pointers in the node if
3007 * we aren't going to empty it
3009 if (src_nritems - push_items < 8) {
3010 if (push_items <= 8)
3016 push_items = min(src_nritems - 8, push_items);
3018 tree_mod_log_eb_copy(root->fs_info, dst, src, dst_nritems, 0,
3020 copy_extent_buffer(dst, src,
3021 btrfs_node_key_ptr_offset(dst_nritems),
3022 btrfs_node_key_ptr_offset(0),
3023 push_items * sizeof(struct btrfs_key_ptr));
3025 if (push_items < src_nritems) {
3027 * don't call tree_mod_log_eb_move here, key removal was already
3028 * fully logged by tree_mod_log_eb_copy above.
3030 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
3031 btrfs_node_key_ptr_offset(push_items),
3032 (src_nritems - push_items) *
3033 sizeof(struct btrfs_key_ptr));
3035 btrfs_set_header_nritems(src, src_nritems - push_items);
3036 btrfs_set_header_nritems(dst, dst_nritems + push_items);
3037 btrfs_mark_buffer_dirty(src);
3038 btrfs_mark_buffer_dirty(dst);
3044 * try to push data from one node into the next node right in the
3047 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
3048 * error, and > 0 if there was no room in the right hand block.
3050 * this will only push up to 1/2 the contents of the left node over
3052 static int balance_node_right(struct btrfs_trans_handle *trans,
3053 struct btrfs_root *root,
3054 struct extent_buffer *dst,
3055 struct extent_buffer *src)
3063 WARN_ON(btrfs_header_generation(src) != trans->transid);
3064 WARN_ON(btrfs_header_generation(dst) != trans->transid);
3066 src_nritems = btrfs_header_nritems(src);
3067 dst_nritems = btrfs_header_nritems(dst);
3068 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
3069 if (push_items <= 0)
3072 if (src_nritems < 4)
3075 max_push = src_nritems / 2 + 1;
3076 /* don't try to empty the node */
3077 if (max_push >= src_nritems)
3080 if (max_push < push_items)
3081 push_items = max_push;
3083 tree_mod_log_eb_move(root->fs_info, dst, push_items, 0, dst_nritems);
3084 memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
3085 btrfs_node_key_ptr_offset(0),
3087 sizeof(struct btrfs_key_ptr));
3089 tree_mod_log_eb_copy(root->fs_info, dst, src, 0,
3090 src_nritems - push_items, push_items);
3091 copy_extent_buffer(dst, src,
3092 btrfs_node_key_ptr_offset(0),
3093 btrfs_node_key_ptr_offset(src_nritems - push_items),
3094 push_items * sizeof(struct btrfs_key_ptr));
3096 btrfs_set_header_nritems(src, src_nritems - push_items);
3097 btrfs_set_header_nritems(dst, dst_nritems + push_items);
3099 btrfs_mark_buffer_dirty(src);
3100 btrfs_mark_buffer_dirty(dst);
3106 * helper function to insert a new root level in the tree.
3107 * A new node is allocated, and a single item is inserted to
3108 * point to the existing root
3110 * returns zero on success or < 0 on failure.
3112 static noinline int insert_new_root(struct btrfs_trans_handle *trans,
3113 struct btrfs_root *root,
3114 struct btrfs_path *path, int level)
3117 struct extent_buffer *lower;
3118 struct extent_buffer *c;
3119 struct extent_buffer *old;
3120 struct btrfs_disk_key lower_key;
3122 BUG_ON(path->nodes[level]);
3123 BUG_ON(path->nodes[level-1] != root->node);
3125 lower = path->nodes[level-1];
3127 btrfs_item_key(lower, &lower_key, 0);
3129 btrfs_node_key(lower, &lower_key, 0);
3131 c = btrfs_alloc_free_block(trans, root, root->nodesize, 0,
3132 root->root_key.objectid, &lower_key,
3133 level, root->node->start, 0);
3137 root_add_used(root, root->nodesize);
3139 memset_extent_buffer(c, 0, 0, sizeof(struct btrfs_header));
3140 btrfs_set_header_nritems(c, 1);
3141 btrfs_set_header_level(c, level);
3142 btrfs_set_header_bytenr(c, c->start);
3143 btrfs_set_header_generation(c, trans->transid);
3144 btrfs_set_header_backref_rev(c, BTRFS_MIXED_BACKREF_REV);
3145 btrfs_set_header_owner(c, root->root_key.objectid);
3147 write_extent_buffer(c, root->fs_info->fsid,
3148 (unsigned long)btrfs_header_fsid(c),
3151 write_extent_buffer(c, root->fs_info->chunk_tree_uuid,
3152 (unsigned long)btrfs_header_chunk_tree_uuid(c),
3155 btrfs_set_node_key(c, &lower_key, 0);
3156 btrfs_set_node_blockptr(c, 0, lower->start);
3157 lower_gen = btrfs_header_generation(lower);
3158 WARN_ON(lower_gen != trans->transid);
3160 btrfs_set_node_ptr_generation(c, 0, lower_gen);
3162 btrfs_mark_buffer_dirty(c);
3165 tree_mod_log_set_root_pointer(root, c, 0);
3166 rcu_assign_pointer(root->node, c);
3168 /* the super has an extra ref to root->node */
3169 free_extent_buffer(old);
3171 add_root_to_dirty_list(root);
3172 extent_buffer_get(c);
3173 path->nodes[level] = c;
3174 path->locks[level] = BTRFS_WRITE_LOCK;
3175 path->slots[level] = 0;
3180 * worker function to insert a single pointer in a node.
3181 * the node should have enough room for the pointer already
3183 * slot and level indicate where you want the key to go, and
3184 * blocknr is the block the key points to.
3186 static void insert_ptr(struct btrfs_trans_handle *trans,
3187 struct btrfs_root *root, struct btrfs_path *path,
3188 struct btrfs_disk_key *key, u64 bytenr,
3189 int slot, int level)
3191 struct extent_buffer *lower;
3195 BUG_ON(!path->nodes[level]);
3196 btrfs_assert_tree_locked(path->nodes[level]);
3197 lower = path->nodes[level];
3198 nritems = btrfs_header_nritems(lower);
3199 BUG_ON(slot > nritems);
3200 BUG_ON(nritems == BTRFS_NODEPTRS_PER_BLOCK(root));
3201 if (slot != nritems) {
3203 tree_mod_log_eb_move(root->fs_info, lower, slot + 1,
3204 slot, nritems - slot);
3205 memmove_extent_buffer(lower,
3206 btrfs_node_key_ptr_offset(slot + 1),
3207 btrfs_node_key_ptr_offset(slot),
3208 (nritems - slot) * sizeof(struct btrfs_key_ptr));
3211 ret = tree_mod_log_insert_key(root->fs_info, lower, slot,
3215 btrfs_set_node_key(lower, key, slot);
3216 btrfs_set_node_blockptr(lower, slot, bytenr);
3217 WARN_ON(trans->transid == 0);
3218 btrfs_set_node_ptr_generation(lower, slot, trans->transid);
3219 btrfs_set_header_nritems(lower, nritems + 1);
3220 btrfs_mark_buffer_dirty(lower);
3224 * split the node at the specified level in path in two.
3225 * The path is corrected to point to the appropriate node after the split
3227 * Before splitting this tries to make some room in the node by pushing
3228 * left and right, if either one works, it returns right away.
3230 * returns 0 on success and < 0 on failure
3232 static noinline int split_node(struct btrfs_trans_handle *trans,
3233 struct btrfs_root *root,
3234 struct btrfs_path *path, int level)
3236 struct extent_buffer *c;
3237 struct extent_buffer *split;
3238 struct btrfs_disk_key disk_key;
3243 c = path->nodes[level];
3244 WARN_ON(btrfs_header_generation(c) != trans->transid);
3245 if (c == root->node) {
3247 * trying to split the root, lets make a new one
3249 * tree mod log: We don't log_removal old root in
3250 * insert_new_root, because that root buffer will be kept as a
3251 * normal node. We are going to log removal of half of the
3252 * elements below with tree_mod_log_eb_copy. We're holding a
3253 * tree lock on the buffer, which is why we cannot race with
3254 * other tree_mod_log users.
3256 ret = insert_new_root(trans, root, path, level + 1);
3260 ret = push_nodes_for_insert(trans, root, path, level);
3261 c = path->nodes[level];
3262 if (!ret && btrfs_header_nritems(c) <
3263 BTRFS_NODEPTRS_PER_BLOCK(root) - 3)
3269 c_nritems = btrfs_header_nritems(c);
3270 mid = (c_nritems + 1) / 2;
3271 btrfs_node_key(c, &disk_key, mid);
3273 split = btrfs_alloc_free_block(trans, root, root->nodesize, 0,
3274 root->root_key.objectid,
3275 &disk_key, level, c->start, 0);
3277 return PTR_ERR(split);
3279 root_add_used(root, root->nodesize);
3281 memset_extent_buffer(split, 0, 0, sizeof(struct btrfs_header));
3282 btrfs_set_header_level(split, btrfs_header_level(c));
3283 btrfs_set_header_bytenr(split, split->start);
3284 btrfs_set_header_generation(split, trans->transid);
3285 btrfs_set_header_backref_rev(split, BTRFS_MIXED_BACKREF_REV);
3286 btrfs_set_header_owner(split, root->root_key.objectid);
3287 write_extent_buffer(split, root->fs_info->fsid,
3288 (unsigned long)btrfs_header_fsid(split),
3290 write_extent_buffer(split, root->fs_info->chunk_tree_uuid,
3291 (unsigned long)btrfs_header_chunk_tree_uuid(split),
3294 tree_mod_log_eb_copy(root->fs_info, split, c, 0, mid, c_nritems - mid);
3295 copy_extent_buffer(split, c,
3296 btrfs_node_key_ptr_offset(0),
3297 btrfs_node_key_ptr_offset(mid),
3298 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
3299 btrfs_set_header_nritems(split, c_nritems - mid);
3300 btrfs_set_header_nritems(c, mid);
3303 btrfs_mark_buffer_dirty(c);
3304 btrfs_mark_buffer_dirty(split);
3306 insert_ptr(trans, root, path, &disk_key, split->start,
3307 path->slots[level + 1] + 1, level + 1);
3309 if (path->slots[level] >= mid) {
3310 path->slots[level] -= mid;
3311 btrfs_tree_unlock(c);
3312 free_extent_buffer(c);
3313 path->nodes[level] = split;
3314 path->slots[level + 1] += 1;
3316 btrfs_tree_unlock(split);
3317 free_extent_buffer(split);
3323 * how many bytes are required to store the items in a leaf. start
3324 * and nr indicate which items in the leaf to check. This totals up the
3325 * space used both by the item structs and the item data
3327 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
3329 struct btrfs_item *start_item;
3330 struct btrfs_item *end_item;
3331 struct btrfs_map_token token;
3333 int nritems = btrfs_header_nritems(l);
3334 int end = min(nritems, start + nr) - 1;
3338 btrfs_init_map_token(&token);
3339 start_item = btrfs_item_nr(l, start);
3340 end_item = btrfs_item_nr(l, end);
3341 data_len = btrfs_token_item_offset(l, start_item, &token) +
3342 btrfs_token_item_size(l, start_item, &token);
3343 data_len = data_len - btrfs_token_item_offset(l, end_item, &token);
3344 data_len += sizeof(struct btrfs_item) * nr;
3345 WARN_ON(data_len < 0);
3350 * The space between the end of the leaf items and
3351 * the start of the leaf data. IOW, how much room
3352 * the leaf has left for both items and data
3354 noinline int btrfs_leaf_free_space(struct btrfs_root *root,
3355 struct extent_buffer *leaf)
3357 int nritems = btrfs_header_nritems(leaf);
3359 ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
3361 printk(KERN_CRIT "leaf free space ret %d, leaf data size %lu, "
3362 "used %d nritems %d\n",
3363 ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
3364 leaf_space_used(leaf, 0, nritems), nritems);
3370 * min slot controls the lowest index we're willing to push to the
3371 * right. We'll push up to and including min_slot, but no lower
3373 static noinline int __push_leaf_right(struct btrfs_trans_handle *trans,
3374 struct btrfs_root *root,
3375 struct btrfs_path *path,
3376 int data_size, int empty,
3377 struct extent_buffer *right,
3378 int free_space, u32 left_nritems,
3381 struct extent_buffer *left = path->nodes[0];
3382 struct extent_buffer *upper = path->nodes[1];
3383 struct btrfs_map_token token;
3384 struct btrfs_disk_key disk_key;
3389 struct btrfs_item *item;
3395 btrfs_init_map_token(&token);
3400 nr = max_t(u32, 1, min_slot);
3402 if (path->slots[0] >= left_nritems)
3403 push_space += data_size;
3405 slot = path->slots[1];
3406 i = left_nritems - 1;
3408 item = btrfs_item_nr(left, i);
3410 if (!empty && push_items > 0) {
3411 if (path->slots[0] > i)
3413 if (path->slots[0] == i) {
3414 int space = btrfs_leaf_free_space(root, left);
3415 if (space + push_space * 2 > free_space)
3420 if (path->slots[0] == i)
3421 push_space += data_size;
3423 this_item_size = btrfs_item_size(left, item);
3424 if (this_item_size + sizeof(*item) + push_space > free_space)
3428 push_space += this_item_size + sizeof(*item);
3434 if (push_items == 0)
3437 WARN_ON(!empty && push_items == left_nritems);
3439 /* push left to right */
3440 right_nritems = btrfs_header_nritems(right);
3442 push_space = btrfs_item_end_nr(left, left_nritems - push_items);
3443 push_space -= leaf_data_end(root, left);
3445 /* make room in the right data area */
3446 data_end = leaf_data_end(root, right);
3447 memmove_extent_buffer(right,
3448 btrfs_leaf_data(right) + data_end - push_space,
3449 btrfs_leaf_data(right) + data_end,
3450 BTRFS_LEAF_DATA_SIZE(root) - data_end);
3452 /* copy from the left data area */
3453 copy_extent_buffer(right, left, btrfs_leaf_data(right) +
3454 BTRFS_LEAF_DATA_SIZE(root) - push_space,
3455 btrfs_leaf_data(left) + leaf_data_end(root, left),
3458 memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
3459 btrfs_item_nr_offset(0),
3460 right_nritems * sizeof(struct btrfs_item));
3462 /* copy the items from left to right */
3463 copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
3464 btrfs_item_nr_offset(left_nritems - push_items),
3465 push_items * sizeof(struct btrfs_item));
3467 /* update the item pointers */
3468 right_nritems += push_items;
3469 btrfs_set_header_nritems(right, right_nritems);
3470 push_space = BTRFS_LEAF_DATA_SIZE(root);
3471 for (i = 0; i < right_nritems; i++) {
3472 item = btrfs_item_nr(right, i);
3473 push_space -= btrfs_token_item_size(right, item, &token);
3474 btrfs_set_token_item_offset(right, item, push_space, &token);
3477 left_nritems -= push_items;
3478 btrfs_set_header_nritems(left, left_nritems);
3481 btrfs_mark_buffer_dirty(left);
3483 clean_tree_block(trans, root, left);
3485 btrfs_mark_buffer_dirty(right);
3487 btrfs_item_key(right, &disk_key, 0);
3488 btrfs_set_node_key(upper, &disk_key, slot + 1);
3489 btrfs_mark_buffer_dirty(upper);
3491 /* then fixup the leaf pointer in the path */
3492 if (path->slots[0] >= left_nritems) {
3493 path->slots[0] -= left_nritems;
3494 if (btrfs_header_nritems(path->nodes[0]) == 0)
3495 clean_tree_block(trans, root, path->nodes[0]);
3496 btrfs_tree_unlock(path->nodes[0]);
3497 free_extent_buffer(path->nodes[0]);
3498 path->nodes[0] = right;
3499 path->slots[1] += 1;
3501 btrfs_tree_unlock(right);
3502 free_extent_buffer(right);
3507 btrfs_tree_unlock(right);
3508 free_extent_buffer(right);
3513 * push some data in the path leaf to the right, trying to free up at
3514 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3516 * returns 1 if the push failed because the other node didn't have enough
3517 * room, 0 if everything worked out and < 0 if there were major errors.
3519 * this will push starting from min_slot to the end of the leaf. It won't
3520 * push any slot lower than min_slot
3522 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
3523 *root, struct btrfs_path *path,
3524 int min_data_size, int data_size,
3525 int empty, u32 min_slot)
3527 struct extent_buffer *left = path->nodes[0];
3528 struct extent_buffer *right;
3529 struct extent_buffer *upper;
3535 if (!path->nodes[1])
3538 slot = path->slots[1];
3539 upper = path->nodes[1];
3540 if (slot >= btrfs_header_nritems(upper) - 1)
3543 btrfs_assert_tree_locked(path->nodes[1]);
3545 right = read_node_slot(root, upper, slot + 1);
3549 btrfs_tree_lock(right);
3550 btrfs_set_lock_blocking(right);
3552 free_space = btrfs_leaf_free_space(root, right);
3553 if (free_space < data_size)
3556 /* cow and double check */
3557 ret = btrfs_cow_block(trans, root, right, upper,
3562 free_space = btrfs_leaf_free_space(root, right);
3563 if (free_space < data_size)
3566 left_nritems = btrfs_header_nritems(left);
3567 if (left_nritems == 0)
3570 return __push_leaf_right(trans, root, path, min_data_size, empty,
3571 right, free_space, left_nritems, min_slot);
3573 btrfs_tree_unlock(right);
3574 free_extent_buffer(right);
3579 * push some data in the path leaf to the left, trying to free up at
3580 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3582 * max_slot can put a limit on how far into the leaf we'll push items. The
3583 * item at 'max_slot' won't be touched. Use (u32)-1 to make us do all the
3586 static noinline int __push_leaf_left(struct btrfs_trans_handle *trans,
3587 struct btrfs_root *root,
3588 struct btrfs_path *path, int data_size,
3589 int empty, struct extent_buffer *left,
3590 int free_space, u32 right_nritems,
3593 struct btrfs_disk_key disk_key;
3594 struct extent_buffer *right = path->nodes[0];
3598 struct btrfs_item *item;
3599 u32 old_left_nritems;
3603 u32 old_left_item_size;
3604 struct btrfs_map_token token;
3606 btrfs_init_map_token(&token);
3609 nr = min(right_nritems, max_slot);
3611 nr = min(right_nritems - 1, max_slot);
3613 for (i = 0; i < nr; i++) {
3614 item = btrfs_item_nr(right, i);
3616 if (!empty && push_items > 0) {
3617 if (path->slots[0] < i)
3619 if (path->slots[0] == i) {
3620 int space = btrfs_leaf_free_space(root, right);
3621 if (space + push_space * 2 > free_space)
3626 if (path->slots[0] == i)
3627 push_space += data_size;
3629 this_item_size = btrfs_item_size(right, item);
3630 if (this_item_size + sizeof(*item) + push_space > free_space)
3634 push_space += this_item_size + sizeof(*item);
3637 if (push_items == 0) {
3641 if (!empty && push_items == btrfs_header_nritems(right))
3644 /* push data from right to left */
3645 copy_extent_buffer(left, right,
3646 btrfs_item_nr_offset(btrfs_header_nritems(left)),
3647 btrfs_item_nr_offset(0),
3648 push_items * sizeof(struct btrfs_item));
3650 push_space = BTRFS_LEAF_DATA_SIZE(root) -
3651 btrfs_item_offset_nr(right, push_items - 1);
3653 copy_extent_buffer(left, right, btrfs_leaf_data(left) +
3654 leaf_data_end(root, left) - push_space,
3655 btrfs_leaf_data(right) +
3656 btrfs_item_offset_nr(right, push_items - 1),
3658 old_left_nritems = btrfs_header_nritems(left);
3659 BUG_ON(old_left_nritems <= 0);
3661 old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
3662 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
3665 item = btrfs_item_nr(left, i);
3667 ioff = btrfs_token_item_offset(left, item, &token);
3668 btrfs_set_token_item_offset(left, item,
3669 ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size),
3672 btrfs_set_header_nritems(left, old_left_nritems + push_items);
3674 /* fixup right node */
3675 if (push_items > right_nritems)
3676 WARN(1, KERN_CRIT "push items %d nr %u\n", push_items,
3679 if (push_items < right_nritems) {
3680 push_space = btrfs_item_offset_nr(right, push_items - 1) -
3681 leaf_data_end(root, right);
3682 memmove_extent_buffer(right, btrfs_leaf_data(right) +
3683 BTRFS_LEAF_DATA_SIZE(root) - push_space,
3684 btrfs_leaf_data(right) +
3685 leaf_data_end(root, right), push_space);
3687 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
3688 btrfs_item_nr_offset(push_items),
3689 (btrfs_header_nritems(right) - push_items) *
3690 sizeof(struct btrfs_item));
3692 right_nritems -= push_items;
3693 btrfs_set_header_nritems(right, right_nritems);
3694 push_space = BTRFS_LEAF_DATA_SIZE(root);
3695 for (i = 0; i < right_nritems; i++) {
3696 item = btrfs_item_nr(right, i);
3698 push_space = push_space - btrfs_token_item_size(right,
3700 btrfs_set_token_item_offset(right, item, push_space, &token);
3703 btrfs_mark_buffer_dirty(left);
3705 btrfs_mark_buffer_dirty(right);
3707 clean_tree_block(trans, root, right);
3709 btrfs_item_key(right, &disk_key, 0);
3710 fixup_low_keys(root, path, &disk_key, 1);
3712 /* then fixup the leaf pointer in the path */
3713 if (path->slots[0] < push_items) {
3714 path->slots[0] += old_left_nritems;
3715 btrfs_tree_unlock(path->nodes[0]);
3716 free_extent_buffer(path->nodes[0]);
3717 path->nodes[0] = left;
3718 path->slots[1] -= 1;
3720 btrfs_tree_unlock(left);
3721 free_extent_buffer(left);
3722 path->slots[0] -= push_items;
3724 BUG_ON(path->slots[0] < 0);
3727 btrfs_tree_unlock(left);
3728 free_extent_buffer(left);
3733 * push some data in the path leaf to the left, trying to free up at
3734 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3736 * max_slot can put a limit on how far into the leaf we'll push items. The
3737 * item at 'max_slot' won't be touched. Use (u32)-1 to make us push all the
3740 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
3741 *root, struct btrfs_path *path, int min_data_size,
3742 int data_size, int empty, u32 max_slot)
3744 struct extent_buffer *right = path->nodes[0];
3745 struct extent_buffer *left;
3751 slot = path->slots[1];
3754 if (!path->nodes[1])
3757 right_nritems = btrfs_header_nritems(right);
3758 if (right_nritems == 0)
3761 btrfs_assert_tree_locked(path->nodes[1]);
3763 left = read_node_slot(root, path->nodes[1], slot - 1);
3767 btrfs_tree_lock(left);
3768 btrfs_set_lock_blocking(left);
3770 free_space = btrfs_leaf_free_space(root, left);
3771 if (free_space < data_size) {
3776 /* cow and double check */
3777 ret = btrfs_cow_block(trans, root, left,
3778 path->nodes[1], slot - 1, &left);
3780 /* we hit -ENOSPC, but it isn't fatal here */
3786 free_space = btrfs_leaf_free_space(root, left);
3787 if (free_space < data_size) {
3792 return __push_leaf_left(trans, root, path, min_data_size,
3793 empty, left, free_space, right_nritems,
3796 btrfs_tree_unlock(left);
3797 free_extent_buffer(left);
3802 * split the path's leaf in two, making sure there is at least data_size
3803 * available for the resulting leaf level of the path.
3805 static noinline void copy_for_split(struct btrfs_trans_handle *trans,
3806 struct btrfs_root *root,
3807 struct btrfs_path *path,
3808 struct extent_buffer *l,
3809 struct extent_buffer *right,
3810 int slot, int mid, int nritems)
3815 struct btrfs_disk_key disk_key;
3816 struct btrfs_map_token token;
3818 btrfs_init_map_token(&token);
3820 nritems = nritems - mid;
3821 btrfs_set_header_nritems(right, nritems);
3822 data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
3824 copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
3825 btrfs_item_nr_offset(mid),
3826 nritems * sizeof(struct btrfs_item));
3828 copy_extent_buffer(right, l,
3829 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
3830 data_copy_size, btrfs_leaf_data(l) +
3831 leaf_data_end(root, l), data_copy_size);
3833 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
3834 btrfs_item_end_nr(l, mid);
3836 for (i = 0; i < nritems; i++) {
3837 struct btrfs_item *item = btrfs_item_nr(right, i);
3840 ioff = btrfs_token_item_offset(right, item, &token);
3841 btrfs_set_token_item_offset(right, item,
3842 ioff + rt_data_off, &token);
3845 btrfs_set_header_nritems(l, mid);
3846 btrfs_item_key(right, &disk_key, 0);
3847 insert_ptr(trans, root, path, &disk_key, right->start,
3848 path->slots[1] + 1, 1);
3850 btrfs_mark_buffer_dirty(right);
3851 btrfs_mark_buffer_dirty(l);
3852 BUG_ON(path->slots[0] != slot);
3855 btrfs_tree_unlock(path->nodes[0]);
3856 free_extent_buffer(path->nodes[0]);
3857 path->nodes[0] = right;
3858 path->slots[0] -= mid;
3859 path->slots[1] += 1;
3861 btrfs_tree_unlock(right);
3862 free_extent_buffer(right);
3865 BUG_ON(path->slots[0] < 0);
3869 * double splits happen when we need to insert a big item in the middle
3870 * of a leaf. A double split can leave us with 3 mostly empty leaves:
3871 * leaf: [ slots 0 - N] [ our target ] [ N + 1 - total in leaf ]
3874 * We avoid this by trying to push the items on either side of our target
3875 * into the adjacent leaves. If all goes well we can avoid the double split
3878 static noinline int push_for_double_split(struct btrfs_trans_handle *trans,
3879 struct btrfs_root *root,
3880 struct btrfs_path *path,
3888 slot = path->slots[0];
3891 * try to push all the items after our slot into the
3894 ret = push_leaf_right(trans, root, path, 1, data_size, 0, slot);
3901 nritems = btrfs_header_nritems(path->nodes[0]);
3903 * our goal is to get our slot at the start or end of a leaf. If
3904 * we've done so we're done
3906 if (path->slots[0] == 0 || path->slots[0] == nritems)
3909 if (btrfs_leaf_free_space(root, path->nodes[0]) >= data_size)
3912 /* try to push all the items before our slot into the next leaf */
3913 slot = path->slots[0];
3914 ret = push_leaf_left(trans, root, path, 1, data_size, 0, slot);
3927 * split the path's leaf in two, making sure there is at least data_size
3928 * available for the resulting leaf level of the path.
3930 * returns 0 if all went well and < 0 on failure.
3932 static noinline int split_leaf(struct btrfs_trans_handle *trans,
3933 struct btrfs_root *root,
3934 struct btrfs_key *ins_key,
3935 struct btrfs_path *path, int data_size,
3938 struct btrfs_disk_key disk_key;
3939 struct extent_buffer *l;
3943 struct extent_buffer *right;
3947 int num_doubles = 0;
3948 int tried_avoid_double = 0;
3951 slot = path->slots[0];
3952 if (extend && data_size + btrfs_item_size_nr(l, slot) +
3953 sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(root))
3956 /* first try to make some room by pushing left and right */
3957 if (data_size && path->nodes[1]) {
3958 wret = push_leaf_right(trans, root, path, data_size,
3963 wret = push_leaf_left(trans, root, path, data_size,
3964 data_size, 0, (u32)-1);
3970 /* did the pushes work? */
3971 if (btrfs_leaf_free_space(root, l) >= data_size)
3975 if (!path->nodes[1]) {
3976 ret = insert_new_root(trans, root, path, 1);
3983 slot = path->slots[0];
3984 nritems = btrfs_header_nritems(l);
3985 mid = (nritems + 1) / 2;
3989 leaf_space_used(l, mid, nritems - mid) + data_size >
3990 BTRFS_LEAF_DATA_SIZE(root)) {
3991 if (slot >= nritems) {
3995 if (mid != nritems &&
3996 leaf_space_used(l, mid, nritems - mid) +
3997 data_size > BTRFS_LEAF_DATA_SIZE(root)) {
3998 if (data_size && !tried_avoid_double)
3999 goto push_for_double;
4005 if (leaf_space_used(l, 0, mid) + data_size >
4006 BTRFS_LEAF_DATA_SIZE(root)) {
4007 if (!extend && data_size && slot == 0) {
4009 } else if ((extend || !data_size) && slot == 0) {
4013 if (mid != nritems &&
4014 leaf_space_used(l, mid, nritems - mid) +
4015 data_size > BTRFS_LEAF_DATA_SIZE(root)) {
4016 if (data_size && !tried_avoid_double)
4017 goto push_for_double;
4025 btrfs_cpu_key_to_disk(&disk_key, ins_key);
4027 btrfs_item_key(l, &disk_key, mid);
4029 right = btrfs_alloc_free_block(trans, root, root->leafsize, 0,
4030 root->root_key.objectid,
4031 &disk_key, 0, l->start, 0);
4033 return PTR_ERR(right);
4035 root_add_used(root, root->leafsize);
4037 memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
4038 btrfs_set_header_bytenr(right, right->start);
4039 btrfs_set_header_generation(right, trans->transid);
4040 btrfs_set_header_backref_rev(right, BTRFS_MIXED_BACKREF_REV);
4041 btrfs_set_header_owner(right, root->root_key.objectid);
4042 btrfs_set_header_level(right, 0);
4043 write_extent_buffer(right, root->fs_info->fsid,
4044 (unsigned long)btrfs_header_fsid(right),
4047 write_extent_buffer(right, root->fs_info->chunk_tree_uuid,
4048 (unsigned long)btrfs_header_chunk_tree_uuid(right),
4053 btrfs_set_header_nritems(right, 0);
4054 insert_ptr(trans, root, path, &disk_key, right->start,
4055 path->slots[1] + 1, 1);
4056 btrfs_tree_unlock(path->nodes[0]);
4057 free_extent_buffer(path->nodes[0]);
4058 path->nodes[0] = right;
4060 path->slots[1] += 1;
4062 btrfs_set_header_nritems(right, 0);
4063 insert_ptr(trans, root, path, &disk_key, right->start,
4065 btrfs_tree_unlock(path->nodes[0]);
4066 free_extent_buffer(path->nodes[0]);
4067 path->nodes[0] = right;
4069 if (path->slots[1] == 0)
4070 fixup_low_keys(root, path, &disk_key, 1);
4072 btrfs_mark_buffer_dirty(right);
4076 copy_for_split(trans, root, path, l, right, slot, mid, nritems);
4079 BUG_ON(num_doubles != 0);
4087 push_for_double_split(trans, root, path, data_size);
4088 tried_avoid_double = 1;
4089 if (btrfs_leaf_free_space(root, path->nodes[0]) >= data_size)
4094 static noinline int setup_leaf_for_split(struct btrfs_trans_handle *trans,
4095 struct btrfs_root *root,
4096 struct btrfs_path *path, int ins_len)
4098 struct btrfs_key key;
4099 struct extent_buffer *leaf;
4100 struct btrfs_file_extent_item *fi;
4105 leaf = path->nodes[0];
4106 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4108 BUG_ON(key.type != BTRFS_EXTENT_DATA_KEY &&
4109 key.type != BTRFS_EXTENT_CSUM_KEY);
4111 if (btrfs_leaf_free_space(root, leaf) >= ins_len)
4114 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
4115 if (key.type == BTRFS_EXTENT_DATA_KEY) {
4116 fi = btrfs_item_ptr(leaf, path->slots[0],
4117 struct btrfs_file_extent_item);
4118 extent_len = btrfs_file_extent_num_bytes(leaf, fi);
4120 btrfs_release_path(path);
4122 path->keep_locks = 1;
4123 path->search_for_split = 1;
4124 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
4125 path->search_for_split = 0;
4130 leaf = path->nodes[0];
4131 /* if our item isn't there or got smaller, return now */
4132 if (ret > 0 || item_size != btrfs_item_size_nr(leaf, path->slots[0]))
4135 /* the leaf has changed, it now has room. return now */
4136 if (btrfs_leaf_free_space(root, path->nodes[0]) >= ins_len)
4139 if (key.type == BTRFS_EXTENT_DATA_KEY) {
4140 fi = btrfs_item_ptr(leaf, path->slots[0],
4141 struct btrfs_file_extent_item);
4142 if (extent_len != btrfs_file_extent_num_bytes(leaf, fi))
4146 btrfs_set_path_blocking(path);
4147 ret = split_leaf(trans, root, &key, path, ins_len, 1);
4151 path->keep_locks = 0;
4152 btrfs_unlock_up_safe(path, 1);
4155 path->keep_locks = 0;
4159 static noinline int split_item(struct btrfs_trans_handle *trans,
4160 struct btrfs_root *root,
4161 struct btrfs_path *path,
4162 struct btrfs_key *new_key,
4163 unsigned long split_offset)
4165 struct extent_buffer *leaf;
4166 struct btrfs_item *item;
4167 struct btrfs_item *new_item;
4173 struct btrfs_disk_key disk_key;
4175 leaf = path->nodes[0];
4176 BUG_ON(btrfs_leaf_free_space(root, leaf) < sizeof(struct btrfs_item));
4178 btrfs_set_path_blocking(path);
4180 item = btrfs_item_nr(leaf, path->slots[0]);
4181 orig_offset = btrfs_item_offset(leaf, item);
4182 item_size = btrfs_item_size(leaf, item);
4184 buf = kmalloc(item_size, GFP_NOFS);
4188 read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf,
4189 path->slots[0]), item_size);
4191 slot = path->slots[0] + 1;
4192 nritems = btrfs_header_nritems(leaf);
4193 if (slot != nritems) {
4194 /* shift the items */
4195 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1),
4196 btrfs_item_nr_offset(slot),
4197 (nritems - slot) * sizeof(struct btrfs_item));
4200 btrfs_cpu_key_to_disk(&disk_key, new_key);
4201 btrfs_set_item_key(leaf, &disk_key, slot);
4203 new_item = btrfs_item_nr(leaf, slot);
4205 btrfs_set_item_offset(leaf, new_item, orig_offset);
4206 btrfs_set_item_size(leaf, new_item, item_size - split_offset);
4208 btrfs_set_item_offset(leaf, item,
4209 orig_offset + item_size - split_offset);
4210 btrfs_set_item_size(leaf, item, split_offset);
4212 btrfs_set_header_nritems(leaf, nritems + 1);
4214 /* write the data for the start of the original item */
4215 write_extent_buffer(leaf, buf,
4216 btrfs_item_ptr_offset(leaf, path->slots[0]),
4219 /* write the data for the new item */
4220 write_extent_buffer(leaf, buf + split_offset,
4221 btrfs_item_ptr_offset(leaf, slot),
4222 item_size - split_offset);
4223 btrfs_mark_buffer_dirty(leaf);
4225 BUG_ON(btrfs_leaf_free_space(root, leaf) < 0);
4231 * This function splits a single item into two items,
4232 * giving 'new_key' to the new item and splitting the
4233 * old one at split_offset (from the start of the item).
4235 * The path may be released by this operation. After
4236 * the split, the path is pointing to the old item. The
4237 * new item is going to be in the same node as the old one.
4239 * Note, the item being split must be smaller enough to live alone on
4240 * a tree block with room for one extra struct btrfs_item
4242 * This allows us to split the item in place, keeping a lock on the
4243 * leaf the entire time.
4245 int btrfs_split_item(struct btrfs_trans_handle *trans,
4246 struct btrfs_root *root,
4247 struct btrfs_path *path,
4248 struct btrfs_key *new_key,
4249 unsigned long split_offset)
4252 ret = setup_leaf_for_split(trans, root, path,
4253 sizeof(struct btrfs_item));
4257 ret = split_item(trans, root, path, new_key, split_offset);
4262 * This function duplicate a item, giving 'new_key' to the new item.
4263 * It guarantees both items live in the same tree leaf and the new item
4264 * is contiguous with the original item.
4266 * This allows us to split file extent in place, keeping a lock on the
4267 * leaf the entire time.
4269 int btrfs_duplicate_item(struct btrfs_trans_handle *trans,
4270 struct btrfs_root *root,
4271 struct btrfs_path *path,
4272 struct btrfs_key *new_key)
4274 struct extent_buffer *leaf;
4278 leaf = path->nodes[0];
4279 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
4280 ret = setup_leaf_for_split(trans, root, path,
4281 item_size + sizeof(struct btrfs_item));
4286 setup_items_for_insert(root, path, new_key, &item_size,
4287 item_size, item_size +
4288 sizeof(struct btrfs_item), 1);
4289 leaf = path->nodes[0];
4290 memcpy_extent_buffer(leaf,
4291 btrfs_item_ptr_offset(leaf, path->slots[0]),
4292 btrfs_item_ptr_offset(leaf, path->slots[0] - 1),
4298 * make the item pointed to by the path smaller. new_size indicates
4299 * how small to make it, and from_end tells us if we just chop bytes
4300 * off the end of the item or if we shift the item to chop bytes off
4303 void btrfs_truncate_item(struct btrfs_root *root, struct btrfs_path *path,
4304 u32 new_size, int from_end)
4307 struct extent_buffer *leaf;
4308 struct btrfs_item *item;
4310 unsigned int data_end;
4311 unsigned int old_data_start;
4312 unsigned int old_size;
4313 unsigned int size_diff;
4315 struct btrfs_map_token token;
4317 btrfs_init_map_token(&token);
4319 leaf = path->nodes[0];
4320 slot = path->slots[0];
4322 old_size = btrfs_item_size_nr(leaf, slot);
4323 if (old_size == new_size)
4326 nritems = btrfs_header_nritems(leaf);
4327 data_end = leaf_data_end(root, leaf);
4329 old_data_start = btrfs_item_offset_nr(leaf, slot);
4331 size_diff = old_size - new_size;
4334 BUG_ON(slot >= nritems);
4337 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4339 /* first correct the data pointers */
4340 for (i = slot; i < nritems; i++) {
4342 item = btrfs_item_nr(leaf, i);
4344 ioff = btrfs_token_item_offset(leaf, item, &token);
4345 btrfs_set_token_item_offset(leaf, item,
4346 ioff + size_diff, &token);
4349 /* shift the data */
4351 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
4352 data_end + size_diff, btrfs_leaf_data(leaf) +
4353 data_end, old_data_start + new_size - data_end);
4355 struct btrfs_disk_key disk_key;
4358 btrfs_item_key(leaf, &disk_key, slot);
4360 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
4362 struct btrfs_file_extent_item *fi;
4364 fi = btrfs_item_ptr(leaf, slot,
4365 struct btrfs_file_extent_item);
4366 fi = (struct btrfs_file_extent_item *)(
4367 (unsigned long)fi - size_diff);
4369 if (btrfs_file_extent_type(leaf, fi) ==
4370 BTRFS_FILE_EXTENT_INLINE) {
4371 ptr = btrfs_item_ptr_offset(leaf, slot);
4372 memmove_extent_buffer(leaf, ptr,
4374 offsetof(struct btrfs_file_extent_item,
4379 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
4380 data_end + size_diff, btrfs_leaf_data(leaf) +
4381 data_end, old_data_start - data_end);
4383 offset = btrfs_disk_key_offset(&disk_key);
4384 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
4385 btrfs_set_item_key(leaf, &disk_key, slot);
4387 fixup_low_keys(root, path, &disk_key, 1);
4390 item = btrfs_item_nr(leaf, slot);
4391 btrfs_set_item_size(leaf, item, new_size);
4392 btrfs_mark_buffer_dirty(leaf);
4394 if (btrfs_leaf_free_space(root, leaf) < 0) {
4395 btrfs_print_leaf(root, leaf);
4401 * make the item pointed to by the path bigger, data_size is the added size.
4403 void btrfs_extend_item(struct btrfs_root *root, struct btrfs_path *path,
4407 struct extent_buffer *leaf;
4408 struct btrfs_item *item;
4410 unsigned int data_end;
4411 unsigned int old_data;
4412 unsigned int old_size;
4414 struct btrfs_map_token token;
4416 btrfs_init_map_token(&token);
4418 leaf = path->nodes[0];
4420 nritems = btrfs_header_nritems(leaf);
4421 data_end = leaf_data_end(root, leaf);
4423 if (btrfs_leaf_free_space(root, leaf) < data_size) {
4424 btrfs_print_leaf(root, leaf);
4427 slot = path->slots[0];
4428 old_data = btrfs_item_end_nr(leaf, slot);
4431 if (slot >= nritems) {
4432 btrfs_print_leaf(root, leaf);
4433 printk(KERN_CRIT "slot %d too large, nritems %d\n",
4439 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4441 /* first correct the data pointers */
4442 for (i = slot; i < nritems; i++) {
4444 item = btrfs_item_nr(leaf, i);
4446 ioff = btrfs_token_item_offset(leaf, item, &token);
4447 btrfs_set_token_item_offset(leaf, item,
4448 ioff - data_size, &token);
4451 /* shift the data */
4452 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
4453 data_end - data_size, btrfs_leaf_data(leaf) +
4454 data_end, old_data - data_end);
4456 data_end = old_data;
4457 old_size = btrfs_item_size_nr(leaf, slot);
4458 item = btrfs_item_nr(leaf, slot);
4459 btrfs_set_item_size(leaf, item, old_size + data_size);
4460 btrfs_mark_buffer_dirty(leaf);
4462 if (btrfs_leaf_free_space(root, leaf) < 0) {
4463 btrfs_print_leaf(root, leaf);
4469 * this is a helper for btrfs_insert_empty_items, the main goal here is
4470 * to save stack depth by doing the bulk of the work in a function
4471 * that doesn't call btrfs_search_slot
4473 void setup_items_for_insert(struct btrfs_root *root, struct btrfs_path *path,
4474 struct btrfs_key *cpu_key, u32 *data_size,
4475 u32 total_data, u32 total_size, int nr)
4477 struct btrfs_item *item;
4480 unsigned int data_end;
4481 struct btrfs_disk_key disk_key;
4482 struct extent_buffer *leaf;
4484 struct btrfs_map_token token;
4486 btrfs_init_map_token(&token);
4488 leaf = path->nodes[0];
4489 slot = path->slots[0];
4491 nritems = btrfs_header_nritems(leaf);
4492 data_end = leaf_data_end(root, leaf);
4494 if (btrfs_leaf_free_space(root, leaf) < total_size) {
4495 btrfs_print_leaf(root, leaf);
4496 printk(KERN_CRIT "not enough freespace need %u have %d\n",
4497 total_size, btrfs_leaf_free_space(root, leaf));
4501 if (slot != nritems) {
4502 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
4504 if (old_data < data_end) {
4505 btrfs_print_leaf(root, leaf);
4506 printk(KERN_CRIT "slot %d old_data %d data_end %d\n",
4507 slot, old_data, data_end);
4511 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4513 /* first correct the data pointers */
4514 for (i = slot; i < nritems; i++) {
4517 item = btrfs_item_nr(leaf, i);
4518 ioff = btrfs_token_item_offset(leaf, item, &token);
4519 btrfs_set_token_item_offset(leaf, item,
4520 ioff - total_data, &token);
4522 /* shift the items */
4523 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
4524 btrfs_item_nr_offset(slot),
4525 (nritems - slot) * sizeof(struct btrfs_item));
4527 /* shift the data */
4528 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
4529 data_end - total_data, btrfs_leaf_data(leaf) +
4530 data_end, old_data - data_end);
4531 data_end = old_data;
4534 /* setup the item for the new data */
4535 for (i = 0; i < nr; i++) {
4536 btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
4537 btrfs_set_item_key(leaf, &disk_key, slot + i);
4538 item = btrfs_item_nr(leaf, slot + i);
4539 btrfs_set_token_item_offset(leaf, item,
4540 data_end - data_size[i], &token);
4541 data_end -= data_size[i];
4542 btrfs_set_token_item_size(leaf, item, data_size[i], &token);
4545 btrfs_set_header_nritems(leaf, nritems + nr);
4548 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
4549 fixup_low_keys(root, path, &disk_key, 1);
4551 btrfs_unlock_up_safe(path, 1);
4552 btrfs_mark_buffer_dirty(leaf);
4554 if (btrfs_leaf_free_space(root, leaf) < 0) {
4555 btrfs_print_leaf(root, leaf);
4561 * Given a key and some data, insert items into the tree.
4562 * This does all the path init required, making room in the tree if needed.
4564 int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
4565 struct btrfs_root *root,
4566 struct btrfs_path *path,
4567 struct btrfs_key *cpu_key, u32 *data_size,
4576 for (i = 0; i < nr; i++)
4577 total_data += data_size[i];
4579 total_size = total_data + (nr * sizeof(struct btrfs_item));
4580 ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
4586 slot = path->slots[0];
4589 setup_items_for_insert(root, path, cpu_key, data_size,
4590 total_data, total_size, nr);
4595 * Given a key and some data, insert an item into the tree.
4596 * This does all the path init required, making room in the tree if needed.
4598 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
4599 *root, struct btrfs_key *cpu_key, void *data, u32
4603 struct btrfs_path *path;
4604 struct extent_buffer *leaf;
4607 path = btrfs_alloc_path();
4610 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
4612 leaf = path->nodes[0];
4613 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
4614 write_extent_buffer(leaf, data, ptr, data_size);
4615 btrfs_mark_buffer_dirty(leaf);
4617 btrfs_free_path(path);
4622 * delete the pointer from a given node.
4624 * the tree should have been previously balanced so the deletion does not
4627 static void del_ptr(struct btrfs_root *root, struct btrfs_path *path,
4628 int level, int slot)
4630 struct extent_buffer *parent = path->nodes[level];
4634 nritems = btrfs_header_nritems(parent);
4635 if (slot != nritems - 1) {
4637 tree_mod_log_eb_move(root->fs_info, parent, slot,
4638 slot + 1, nritems - slot - 1);
4639 memmove_extent_buffer(parent,
4640 btrfs_node_key_ptr_offset(slot),
4641 btrfs_node_key_ptr_offset(slot + 1),
4642 sizeof(struct btrfs_key_ptr) *
4643 (nritems - slot - 1));
4645 ret = tree_mod_log_insert_key(root->fs_info, parent, slot,
4646 MOD_LOG_KEY_REMOVE);
4651 btrfs_set_header_nritems(parent, nritems);
4652 if (nritems == 0 && parent == root->node) {
4653 BUG_ON(btrfs_header_level(root->node) != 1);
4654 /* just turn the root into a leaf and break */
4655 btrfs_set_header_level(root->node, 0);
4656 } else if (slot == 0) {
4657 struct btrfs_disk_key disk_key;
4659 btrfs_node_key(parent, &disk_key, 0);
4660 fixup_low_keys(root, path, &disk_key, level + 1);
4662 btrfs_mark_buffer_dirty(parent);
4666 * a helper function to delete the leaf pointed to by path->slots[1] and
4669 * This deletes the pointer in path->nodes[1] and frees the leaf
4670 * block extent. zero is returned if it all worked out, < 0 otherwise.
4672 * The path must have already been setup for deleting the leaf, including
4673 * all the proper balancing. path->nodes[1] must be locked.
4675 static noinline void btrfs_del_leaf(struct btrfs_trans_handle *trans,
4676 struct btrfs_root *root,
4677 struct btrfs_path *path,
4678 struct extent_buffer *leaf)
4680 WARN_ON(btrfs_header_generation(leaf) != trans->transid);
4681 del_ptr(root, path, 1, path->slots[1]);
4684 * btrfs_free_extent is expensive, we want to make sure we
4685 * aren't holding any locks when we call it
4687 btrfs_unlock_up_safe(path, 0);
4689 root_sub_used(root, leaf->len);
4691 extent_buffer_get(leaf);
4692 btrfs_free_tree_block(trans, root, leaf, 0, 1);
4693 free_extent_buffer_stale(leaf);
4696 * delete the item at the leaf level in path. If that empties
4697 * the leaf, remove it from the tree
4699 int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
4700 struct btrfs_path *path, int slot, int nr)
4702 struct extent_buffer *leaf;
4703 struct btrfs_item *item;
4710 struct btrfs_map_token token;
4712 btrfs_init_map_token(&token);
4714 leaf = path->nodes[0];
4715 last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
4717 for (i = 0; i < nr; i++)
4718 dsize += btrfs_item_size_nr(leaf, slot + i);
4720 nritems = btrfs_header_nritems(leaf);
4722 if (slot + nr != nritems) {
4723 int data_end = leaf_data_end(root, leaf);
4725 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
4727 btrfs_leaf_data(leaf) + data_end,
4728 last_off - data_end);
4730 for (i = slot + nr; i < nritems; i++) {
4733 item = btrfs_item_nr(leaf, i);
4734 ioff = btrfs_token_item_offset(leaf, item, &token);
4735 btrfs_set_token_item_offset(leaf, item,
4736 ioff + dsize, &token);
4739 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
4740 btrfs_item_nr_offset(slot + nr),
4741 sizeof(struct btrfs_item) *
4742 (nritems - slot - nr));
4744 btrfs_set_header_nritems(leaf, nritems - nr);
4747 /* delete the leaf if we've emptied it */
4749 if (leaf == root->node) {
4750 btrfs_set_header_level(leaf, 0);
4752 btrfs_set_path_blocking(path);
4753 clean_tree_block(trans, root, leaf);
4754 btrfs_del_leaf(trans, root, path, leaf);
4757 int used = leaf_space_used(leaf, 0, nritems);
4759 struct btrfs_disk_key disk_key;
4761 btrfs_item_key(leaf, &disk_key, 0);
4762 fixup_low_keys(root, path, &disk_key, 1);
4765 /* delete the leaf if it is mostly empty */
4766 if (used < BTRFS_LEAF_DATA_SIZE(root) / 3) {
4767 /* push_leaf_left fixes the path.
4768 * make sure the path still points to our leaf
4769 * for possible call to del_ptr below
4771 slot = path->slots[1];
4772 extent_buffer_get(leaf);
4774 btrfs_set_path_blocking(path);
4775 wret = push_leaf_left(trans, root, path, 1, 1,
4777 if (wret < 0 && wret != -ENOSPC)
4780 if (path->nodes[0] == leaf &&
4781 btrfs_header_nritems(leaf)) {
4782 wret = push_leaf_right(trans, root, path, 1,
4784 if (wret < 0 && wret != -ENOSPC)
4788 if (btrfs_header_nritems(leaf) == 0) {
4789 path->slots[1] = slot;
4790 btrfs_del_leaf(trans, root, path, leaf);
4791 free_extent_buffer(leaf);
4794 /* if we're still in the path, make sure
4795 * we're dirty. Otherwise, one of the
4796 * push_leaf functions must have already
4797 * dirtied this buffer
4799 if (path->nodes[0] == leaf)
4800 btrfs_mark_buffer_dirty(leaf);
4801 free_extent_buffer(leaf);
4804 btrfs_mark_buffer_dirty(leaf);
4811 * search the tree again to find a leaf with lesser keys
4812 * returns 0 if it found something or 1 if there are no lesser leaves.
4813 * returns < 0 on io errors.
4815 * This may release the path, and so you may lose any locks held at the
4818 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
4820 struct btrfs_key key;
4821 struct btrfs_disk_key found_key;
4824 btrfs_item_key_to_cpu(path->nodes[0], &key, 0);
4828 else if (key.type > 0)
4830 else if (key.objectid > 0)
4835 btrfs_release_path(path);
4836 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4839 btrfs_item_key(path->nodes[0], &found_key, 0);
4840 ret = comp_keys(&found_key, &key);
4847 * A helper function to walk down the tree starting at min_key, and looking
4848 * for nodes or leaves that are have a minimum transaction id.
4849 * This is used by the btree defrag code, and tree logging
4851 * This does not cow, but it does stuff the starting key it finds back
4852 * into min_key, so you can call btrfs_search_slot with cow=1 on the
4853 * key and get a writable path.
4855 * This does lock as it descends, and path->keep_locks should be set
4856 * to 1 by the caller.
4858 * This honors path->lowest_level to prevent descent past a given level
4861 * min_trans indicates the oldest transaction that you are interested
4862 * in walking through. Any nodes or leaves older than min_trans are
4863 * skipped over (without reading them).
4865 * returns zero if something useful was found, < 0 on error and 1 if there
4866 * was nothing in the tree that matched the search criteria.
4868 int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
4869 struct btrfs_key *max_key,
4870 struct btrfs_path *path,
4873 struct extent_buffer *cur;
4874 struct btrfs_key found_key;
4881 WARN_ON(!path->keep_locks);
4883 cur = btrfs_read_lock_root_node(root);
4884 level = btrfs_header_level(cur);
4885 WARN_ON(path->nodes[level]);
4886 path->nodes[level] = cur;
4887 path->locks[level] = BTRFS_READ_LOCK;
4889 if (btrfs_header_generation(cur) < min_trans) {
4894 nritems = btrfs_header_nritems(cur);
4895 level = btrfs_header_level(cur);
4896 sret = bin_search(cur, min_key, level, &slot);
4898 /* at the lowest level, we're done, setup the path and exit */
4899 if (level == path->lowest_level) {
4900 if (slot >= nritems)
4903 path->slots[level] = slot;
4904 btrfs_item_key_to_cpu(cur, &found_key, slot);
4907 if (sret && slot > 0)
4910 * check this node pointer against the min_trans parameters.
4911 * If it is too old, old, skip to the next one.
4913 while (slot < nritems) {
4917 blockptr = btrfs_node_blockptr(cur, slot);
4918 gen = btrfs_node_ptr_generation(cur, slot);
4919 if (gen < min_trans) {
4927 * we didn't find a candidate key in this node, walk forward
4928 * and find another one
4930 if (slot >= nritems) {
4931 path->slots[level] = slot;
4932 btrfs_set_path_blocking(path);
4933 sret = btrfs_find_next_key(root, path, min_key, level,
4936 btrfs_release_path(path);
4942 /* save our key for returning back */
4943 btrfs_node_key_to_cpu(cur, &found_key, slot);
4944 path->slots[level] = slot;
4945 if (level == path->lowest_level) {
4947 unlock_up(path, level, 1, 0, NULL);
4950 btrfs_set_path_blocking(path);
4951 cur = read_node_slot(root, cur, slot);
4952 BUG_ON(!cur); /* -ENOMEM */
4954 btrfs_tree_read_lock(cur);
4956 path->locks[level - 1] = BTRFS_READ_LOCK;
4957 path->nodes[level - 1] = cur;
4958 unlock_up(path, level, 1, 0, NULL);
4959 btrfs_clear_path_blocking(path, NULL, 0);
4963 memcpy(min_key, &found_key, sizeof(found_key));
4964 btrfs_set_path_blocking(path);
4968 static void tree_move_down(struct btrfs_root *root,
4969 struct btrfs_path *path,
4970 int *level, int root_level)
4972 BUG_ON(*level == 0);
4973 path->nodes[*level - 1] = read_node_slot(root, path->nodes[*level],
4974 path->slots[*level]);
4975 path->slots[*level - 1] = 0;
4979 static int tree_move_next_or_upnext(struct btrfs_root *root,
4980 struct btrfs_path *path,
4981 int *level, int root_level)
4985 nritems = btrfs_header_nritems(path->nodes[*level]);
4987 path->slots[*level]++;
4989 while (path->slots[*level] >= nritems) {
4990 if (*level == root_level)
4994 path->slots[*level] = 0;
4995 free_extent_buffer(path->nodes[*level]);
4996 path->nodes[*level] = NULL;
4998 path->slots[*level]++;
5000 nritems = btrfs_header_nritems(path->nodes[*level]);
5007 * Returns 1 if it had to move up and next. 0 is returned if it moved only next
5010 static int tree_advance(struct btrfs_root *root,
5011 struct btrfs_path *path,
5012 int *level, int root_level,
5014 struct btrfs_key *key)
5018 if (*level == 0 || !allow_down) {
5019 ret = tree_move_next_or_upnext(root, path, level, root_level);
5021 tree_move_down(root, path, level, root_level);
5026 btrfs_item_key_to_cpu(path->nodes[*level], key,
5027 path->slots[*level]);
5029 btrfs_node_key_to_cpu(path->nodes[*level], key,
5030 path->slots[*level]);
5035 static int tree_compare_item(struct btrfs_root *left_root,
5036 struct btrfs_path *left_path,
5037 struct btrfs_path *right_path,
5042 unsigned long off1, off2;
5044 len1 = btrfs_item_size_nr(left_path->nodes[0], left_path->slots[0]);
5045 len2 = btrfs_item_size_nr(right_path->nodes[0], right_path->slots[0]);
5049 off1 = btrfs_item_ptr_offset(left_path->nodes[0], left_path->slots[0]);
5050 off2 = btrfs_item_ptr_offset(right_path->nodes[0],
5051 right_path->slots[0]);
5053 read_extent_buffer(left_path->nodes[0], tmp_buf, off1, len1);
5055 cmp = memcmp_extent_buffer(right_path->nodes[0], tmp_buf, off2, len1);
5062 #define ADVANCE_ONLY_NEXT -1
5065 * This function compares two trees and calls the provided callback for
5066 * every changed/new/deleted item it finds.
5067 * If shared tree blocks are encountered, whole subtrees are skipped, making
5068 * the compare pretty fast on snapshotted subvolumes.
5070 * This currently works on commit roots only. As commit roots are read only,
5071 * we don't do any locking. The commit roots are protected with transactions.
5072 * Transactions are ended and rejoined when a commit is tried in between.
5074 * This function checks for modifications done to the trees while comparing.
5075 * If it detects a change, it aborts immediately.
5077 int btrfs_compare_trees(struct btrfs_root *left_root,
5078 struct btrfs_root *right_root,
5079 btrfs_changed_cb_t changed_cb, void *ctx)
5083 struct btrfs_trans_handle *trans = NULL;
5084 struct btrfs_path *left_path = NULL;
5085 struct btrfs_path *right_path = NULL;
5086 struct btrfs_key left_key;
5087 struct btrfs_key right_key;
5088 char *tmp_buf = NULL;
5089 int left_root_level;
5090 int right_root_level;
5093 int left_end_reached;
5094 int right_end_reached;
5099 u64 left_start_ctransid;
5100 u64 right_start_ctransid;
5103 left_path = btrfs_alloc_path();
5108 right_path = btrfs_alloc_path();
5114 tmp_buf = kmalloc(left_root->leafsize, GFP_NOFS);
5120 left_path->search_commit_root = 1;
5121 left_path->skip_locking = 1;
5122 right_path->search_commit_root = 1;
5123 right_path->skip_locking = 1;
5125 spin_lock(&left_root->root_item_lock);
5126 left_start_ctransid = btrfs_root_ctransid(&left_root->root_item);
5127 spin_unlock(&left_root->root_item_lock);
5129 spin_lock(&right_root->root_item_lock);
5130 right_start_ctransid = btrfs_root_ctransid(&right_root->root_item);
5131 spin_unlock(&right_root->root_item_lock);
5133 trans = btrfs_join_transaction(left_root);
5134 if (IS_ERR(trans)) {
5135 ret = PTR_ERR(trans);
5141 * Strategy: Go to the first items of both trees. Then do
5143 * If both trees are at level 0
5144 * Compare keys of current items
5145 * If left < right treat left item as new, advance left tree
5147 * If left > right treat right item as deleted, advance right tree
5149 * If left == right do deep compare of items, treat as changed if
5150 * needed, advance both trees and repeat
5151 * If both trees are at the same level but not at level 0
5152 * Compare keys of current nodes/leafs
5153 * If left < right advance left tree and repeat
5154 * If left > right advance right tree and repeat
5155 * If left == right compare blockptrs of the next nodes/leafs
5156 * If they match advance both trees but stay at the same level
5158 * If they don't match advance both trees while allowing to go
5160 * If tree levels are different
5161 * Advance the tree that needs it and repeat
5163 * Advancing a tree means:
5164 * If we are at level 0, try to go to the next slot. If that's not
5165 * possible, go one level up and repeat. Stop when we found a level
5166 * where we could go to the next slot. We may at this point be on a
5169 * If we are not at level 0 and not on shared tree blocks, go one
5172 * If we are not at level 0 and on shared tree blocks, go one slot to
5173 * the right if possible or go up and right.
5176 left_level = btrfs_header_level(left_root->commit_root);
5177 left_root_level = left_level;
5178 left_path->nodes[left_level] = left_root->commit_root;
5179 extent_buffer_get(left_path->nodes[left_level]);
5181 right_level = btrfs_header_level(right_root->commit_root);
5182 right_root_level = right_level;
5183 right_path->nodes[right_level] = right_root->commit_root;
5184 extent_buffer_get(right_path->nodes[right_level]);
5186 if (left_level == 0)
5187 btrfs_item_key_to_cpu(left_path->nodes[left_level],
5188 &left_key, left_path->slots[left_level]);
5190 btrfs_node_key_to_cpu(left_path->nodes[left_level],
5191 &left_key, left_path->slots[left_level]);
5192 if (right_level == 0)
5193 btrfs_item_key_to_cpu(right_path->nodes[right_level],
5194 &right_key, right_path->slots[right_level]);
5196 btrfs_node_key_to_cpu(right_path->nodes[right_level],
5197 &right_key, right_path->slots[right_level]);
5199 left_end_reached = right_end_reached = 0;
5200 advance_left = advance_right = 0;
5204 * We need to make sure the transaction does not get committed
5205 * while we do anything on commit roots. This means, we need to
5206 * join and leave transactions for every item that we process.
5208 if (trans && btrfs_should_end_transaction(trans, left_root)) {
5209 btrfs_release_path(left_path);
5210 btrfs_release_path(right_path);
5212 ret = btrfs_end_transaction(trans, left_root);
5217 /* now rejoin the transaction */
5219 trans = btrfs_join_transaction(left_root);
5220 if (IS_ERR(trans)) {
5221 ret = PTR_ERR(trans);
5226 spin_lock(&left_root->root_item_lock);
5227 ctransid = btrfs_root_ctransid(&left_root->root_item);
5228 spin_unlock(&left_root->root_item_lock);
5229 if (ctransid != left_start_ctransid)
5230 left_start_ctransid = 0;
5232 spin_lock(&right_root->root_item_lock);
5233 ctransid = btrfs_root_ctransid(&right_root->root_item);
5234 spin_unlock(&right_root->root_item_lock);
5235 if (ctransid != right_start_ctransid)
5236 right_start_ctransid = 0;
5238 if (!left_start_ctransid || !right_start_ctransid) {
5239 WARN(1, KERN_WARNING
5240 "btrfs: btrfs_compare_tree detected "
5241 "a change in one of the trees while "
5242 "iterating. This is probably a "
5249 * the commit root may have changed, so start again
5252 left_path->lowest_level = left_level;
5253 right_path->lowest_level = right_level;
5254 ret = btrfs_search_slot(NULL, left_root,
5255 &left_key, left_path, 0, 0);
5258 ret = btrfs_search_slot(NULL, right_root,
5259 &right_key, right_path, 0, 0);
5264 if (advance_left && !left_end_reached) {
5265 ret = tree_advance(left_root, left_path, &left_level,
5267 advance_left != ADVANCE_ONLY_NEXT,
5270 left_end_reached = ADVANCE;
5273 if (advance_right && !right_end_reached) {
5274 ret = tree_advance(right_root, right_path, &right_level,
5276 advance_right != ADVANCE_ONLY_NEXT,
5279 right_end_reached = ADVANCE;
5283 if (left_end_reached && right_end_reached) {
5286 } else if (left_end_reached) {
5287 if (right_level == 0) {
5288 ret = changed_cb(left_root, right_root,
5289 left_path, right_path,
5291 BTRFS_COMPARE_TREE_DELETED,
5296 advance_right = ADVANCE;
5298 } else if (right_end_reached) {
5299 if (left_level == 0) {
5300 ret = changed_cb(left_root, right_root,
5301 left_path, right_path,
5303 BTRFS_COMPARE_TREE_NEW,
5308 advance_left = ADVANCE;
5312 if (left_level == 0 && right_level == 0) {
5313 cmp = btrfs_comp_cpu_keys(&left_key, &right_key);
5315 ret = changed_cb(left_root, right_root,
5316 left_path, right_path,
5318 BTRFS_COMPARE_TREE_NEW,
5322 advance_left = ADVANCE;
5323 } else if (cmp > 0) {
5324 ret = changed_cb(left_root, right_root,
5325 left_path, right_path,
5327 BTRFS_COMPARE_TREE_DELETED,
5331 advance_right = ADVANCE;
5333 WARN_ON(!extent_buffer_uptodate(left_path->nodes[0]));
5334 ret = tree_compare_item(left_root, left_path,
5335 right_path, tmp_buf);
5337 WARN_ON(!extent_buffer_uptodate(left_path->nodes[0]));
5338 ret = changed_cb(left_root, right_root,
5339 left_path, right_path,
5341 BTRFS_COMPARE_TREE_CHANGED,
5346 advance_left = ADVANCE;
5347 advance_right = ADVANCE;
5349 } else if (left_level == right_level) {
5350 cmp = btrfs_comp_cpu_keys(&left_key, &right_key);
5352 advance_left = ADVANCE;
5353 } else if (cmp > 0) {
5354 advance_right = ADVANCE;
5356 left_blockptr = btrfs_node_blockptr(
5357 left_path->nodes[left_level],
5358 left_path->slots[left_level]);
5359 right_blockptr = btrfs_node_blockptr(
5360 right_path->nodes[right_level],
5361 right_path->slots[right_level]);
5362 if (left_blockptr == right_blockptr) {
5364 * As we're on a shared block, don't
5365 * allow to go deeper.
5367 advance_left = ADVANCE_ONLY_NEXT;
5368 advance_right = ADVANCE_ONLY_NEXT;
5370 advance_left = ADVANCE;
5371 advance_right = ADVANCE;
5374 } else if (left_level < right_level) {
5375 advance_right = ADVANCE;
5377 advance_left = ADVANCE;
5382 btrfs_free_path(left_path);
5383 btrfs_free_path(right_path);
5388 ret = btrfs_end_transaction(trans, left_root);
5390 btrfs_end_transaction(trans, left_root);
5397 * this is similar to btrfs_next_leaf, but does not try to preserve
5398 * and fixup the path. It looks for and returns the next key in the
5399 * tree based on the current path and the min_trans parameters.
5401 * 0 is returned if another key is found, < 0 if there are any errors
5402 * and 1 is returned if there are no higher keys in the tree
5404 * path->keep_locks should be set to 1 on the search made before
5405 * calling this function.
5407 int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
5408 struct btrfs_key *key, int level, u64 min_trans)
5411 struct extent_buffer *c;
5413 WARN_ON(!path->keep_locks);
5414 while (level < BTRFS_MAX_LEVEL) {
5415 if (!path->nodes[level])
5418 slot = path->slots[level] + 1;
5419 c = path->nodes[level];
5421 if (slot >= btrfs_header_nritems(c)) {
5424 struct btrfs_key cur_key;
5425 if (level + 1 >= BTRFS_MAX_LEVEL ||
5426 !path->nodes[level + 1])
5429 if (path->locks[level + 1]) {
5434 slot = btrfs_header_nritems(c) - 1;
5436 btrfs_item_key_to_cpu(c, &cur_key, slot);
5438 btrfs_node_key_to_cpu(c, &cur_key, slot);
5440 orig_lowest = path->lowest_level;
5441 btrfs_release_path(path);
5442 path->lowest_level = level;
5443 ret = btrfs_search_slot(NULL, root, &cur_key, path,
5445 path->lowest_level = orig_lowest;
5449 c = path->nodes[level];
5450 slot = path->slots[level];
5457 btrfs_item_key_to_cpu(c, key, slot);
5459 u64 gen = btrfs_node_ptr_generation(c, slot);
5461 if (gen < min_trans) {
5465 btrfs_node_key_to_cpu(c, key, slot);
5473 * search the tree again to find a leaf with greater keys
5474 * returns 0 if it found something or 1 if there are no greater leaves.
5475 * returns < 0 on io errors.
5477 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
5479 return btrfs_next_old_leaf(root, path, 0);
5482 int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
5487 struct extent_buffer *c;
5488 struct extent_buffer *next;
5489 struct btrfs_key key;
5492 int old_spinning = path->leave_spinning;
5493 int next_rw_lock = 0;
5495 nritems = btrfs_header_nritems(path->nodes[0]);
5499 btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1);
5504 btrfs_release_path(path);
5506 path->keep_locks = 1;
5507 path->leave_spinning = 1;
5510 ret = btrfs_search_old_slot(root, &key, path, time_seq);
5512 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5513 path->keep_locks = 0;
5518 nritems = btrfs_header_nritems(path->nodes[0]);
5520 * by releasing the path above we dropped all our locks. A balance
5521 * could have added more items next to the key that used to be
5522 * at the very end of the block. So, check again here and
5523 * advance the path if there are now more items available.
5525 if (nritems > 0 && path->slots[0] < nritems - 1) {
5532 while (level < BTRFS_MAX_LEVEL) {
5533 if (!path->nodes[level]) {
5538 slot = path->slots[level] + 1;
5539 c = path->nodes[level];
5540 if (slot >= btrfs_header_nritems(c)) {
5542 if (level == BTRFS_MAX_LEVEL) {
5550 btrfs_tree_unlock_rw(next, next_rw_lock);
5551 free_extent_buffer(next);
5555 next_rw_lock = path->locks[level];
5556 ret = read_block_for_search(NULL, root, path, &next, level,
5562 btrfs_release_path(path);
5566 if (!path->skip_locking) {
5567 ret = btrfs_try_tree_read_lock(next);
5568 if (!ret && time_seq) {
5570 * If we don't get the lock, we may be racing
5571 * with push_leaf_left, holding that lock while
5572 * itself waiting for the leaf we've currently
5573 * locked. To solve this situation, we give up
5574 * on our lock and cycle.
5576 free_extent_buffer(next);
5577 btrfs_release_path(path);
5582 btrfs_set_path_blocking(path);
5583 btrfs_tree_read_lock(next);
5584 btrfs_clear_path_blocking(path, next,
5587 next_rw_lock = BTRFS_READ_LOCK;
5591 path->slots[level] = slot;
5594 c = path->nodes[level];
5595 if (path->locks[level])
5596 btrfs_tree_unlock_rw(c, path->locks[level]);
5598 free_extent_buffer(c);
5599 path->nodes[level] = next;
5600 path->slots[level] = 0;
5601 if (!path->skip_locking)
5602 path->locks[level] = next_rw_lock;
5606 ret = read_block_for_search(NULL, root, path, &next, level,
5612 btrfs_release_path(path);
5616 if (!path->skip_locking) {
5617 ret = btrfs_try_tree_read_lock(next);
5619 btrfs_set_path_blocking(path);
5620 btrfs_tree_read_lock(next);
5621 btrfs_clear_path_blocking(path, next,
5624 next_rw_lock = BTRFS_READ_LOCK;
5629 unlock_up(path, 0, 1, 0, NULL);
5630 path->leave_spinning = old_spinning;
5632 btrfs_set_path_blocking(path);
5638 * this uses btrfs_prev_leaf to walk backwards in the tree, and keeps
5639 * searching until it gets past min_objectid or finds an item of 'type'
5641 * returns 0 if something is found, 1 if nothing was found and < 0 on error
5643 int btrfs_previous_item(struct btrfs_root *root,
5644 struct btrfs_path *path, u64 min_objectid,
5647 struct btrfs_key found_key;
5648 struct extent_buffer *leaf;
5653 if (path->slots[0] == 0) {
5654 btrfs_set_path_blocking(path);
5655 ret = btrfs_prev_leaf(root, path);
5661 leaf = path->nodes[0];
5662 nritems = btrfs_header_nritems(leaf);
5665 if (path->slots[0] == nritems)
5668 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5669 if (found_key.objectid < min_objectid)
5671 if (found_key.type == type)
5673 if (found_key.objectid == min_objectid &&
5674 found_key.type < type)