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 int tree_mod_log_free_eb(struct btrfs_fs_info *fs_info,
43 struct extent_buffer *eb);
45 struct btrfs_path *btrfs_alloc_path(void)
47 struct btrfs_path *path;
48 path = kmem_cache_zalloc(btrfs_path_cachep, GFP_NOFS);
53 * set all locked nodes in the path to blocking locks. This should
54 * be done before scheduling
56 noinline void btrfs_set_path_blocking(struct btrfs_path *p)
59 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
60 if (!p->nodes[i] || !p->locks[i])
62 btrfs_set_lock_blocking_rw(p->nodes[i], p->locks[i]);
63 if (p->locks[i] == BTRFS_READ_LOCK)
64 p->locks[i] = BTRFS_READ_LOCK_BLOCKING;
65 else if (p->locks[i] == BTRFS_WRITE_LOCK)
66 p->locks[i] = BTRFS_WRITE_LOCK_BLOCKING;
71 * reset all the locked nodes in the patch to spinning locks.
73 * held is used to keep lockdep happy, when lockdep is enabled
74 * we set held to a blocking lock before we go around and
75 * retake all the spinlocks in the path. You can safely use NULL
78 noinline void btrfs_clear_path_blocking(struct btrfs_path *p,
79 struct extent_buffer *held, int held_rw)
84 btrfs_set_lock_blocking_rw(held, held_rw);
85 if (held_rw == BTRFS_WRITE_LOCK)
86 held_rw = BTRFS_WRITE_LOCK_BLOCKING;
87 else if (held_rw == BTRFS_READ_LOCK)
88 held_rw = BTRFS_READ_LOCK_BLOCKING;
90 btrfs_set_path_blocking(p);
92 for (i = BTRFS_MAX_LEVEL - 1; i >= 0; i--) {
93 if (p->nodes[i] && p->locks[i]) {
94 btrfs_clear_lock_blocking_rw(p->nodes[i], p->locks[i]);
95 if (p->locks[i] == BTRFS_WRITE_LOCK_BLOCKING)
96 p->locks[i] = BTRFS_WRITE_LOCK;
97 else if (p->locks[i] == BTRFS_READ_LOCK_BLOCKING)
98 p->locks[i] = BTRFS_READ_LOCK;
103 btrfs_clear_lock_blocking_rw(held, held_rw);
106 /* this also releases the path */
107 void btrfs_free_path(struct btrfs_path *p)
111 btrfs_release_path(p);
112 kmem_cache_free(btrfs_path_cachep, p);
116 * path release drops references on the extent buffers in the path
117 * and it drops any locks held by this path
119 * It is safe to call this on paths that no locks or extent buffers held.
121 noinline void btrfs_release_path(struct btrfs_path *p)
125 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
130 btrfs_tree_unlock_rw(p->nodes[i], p->locks[i]);
133 free_extent_buffer(p->nodes[i]);
139 * safely gets a reference on the root node of a tree. A lock
140 * is not taken, so a concurrent writer may put a different node
141 * at the root of the tree. See btrfs_lock_root_node for the
144 * The extent buffer returned by this has a reference taken, so
145 * it won't disappear. It may stop being the root of the tree
146 * at any time because there are no locks held.
148 struct extent_buffer *btrfs_root_node(struct btrfs_root *root)
150 struct extent_buffer *eb;
154 eb = rcu_dereference(root->node);
157 * RCU really hurts here, we could free up the root node because
158 * it was cow'ed but we may not get the new root node yet so do
159 * the inc_not_zero dance and if it doesn't work then
160 * synchronize_rcu and try again.
162 if (atomic_inc_not_zero(&eb->refs)) {
172 /* loop around taking references on and locking the root node of the
173 * tree until you end up with a lock on the root. A locked buffer
174 * is returned, with a reference held.
176 struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root)
178 struct extent_buffer *eb;
181 eb = btrfs_root_node(root);
183 if (eb == root->node)
185 btrfs_tree_unlock(eb);
186 free_extent_buffer(eb);
191 /* loop around taking references on and locking the root node of the
192 * tree until you end up with a lock on the root. A locked buffer
193 * is returned, with a reference held.
195 static struct extent_buffer *btrfs_read_lock_root_node(struct btrfs_root *root)
197 struct extent_buffer *eb;
200 eb = btrfs_root_node(root);
201 btrfs_tree_read_lock(eb);
202 if (eb == root->node)
204 btrfs_tree_read_unlock(eb);
205 free_extent_buffer(eb);
210 /* cowonly root (everything not a reference counted cow subvolume), just get
211 * put onto a simple dirty list. transaction.c walks this to make sure they
212 * get properly updated on disk.
214 static void add_root_to_dirty_list(struct btrfs_root *root)
216 if (test_bit(BTRFS_ROOT_DIRTY, &root->state) ||
217 !test_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state))
220 spin_lock(&root->fs_info->trans_lock);
221 if (!test_and_set_bit(BTRFS_ROOT_DIRTY, &root->state)) {
222 /* Want the extent tree to be the last on the list */
223 if (root->objectid == BTRFS_EXTENT_TREE_OBJECTID)
224 list_move_tail(&root->dirty_list,
225 &root->fs_info->dirty_cowonly_roots);
227 list_move(&root->dirty_list,
228 &root->fs_info->dirty_cowonly_roots);
230 spin_unlock(&root->fs_info->trans_lock);
234 * used by snapshot creation to make a copy of a root for a tree with
235 * a given objectid. The buffer with the new root node is returned in
236 * cow_ret, and this func returns zero on success or a negative error code.
238 int btrfs_copy_root(struct btrfs_trans_handle *trans,
239 struct btrfs_root *root,
240 struct extent_buffer *buf,
241 struct extent_buffer **cow_ret, u64 new_root_objectid)
243 struct extent_buffer *cow;
246 struct btrfs_disk_key disk_key;
248 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
249 trans->transid != root->fs_info->running_transaction->transid);
250 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
251 trans->transid != root->last_trans);
253 level = btrfs_header_level(buf);
255 btrfs_item_key(buf, &disk_key, 0);
257 btrfs_node_key(buf, &disk_key, 0);
259 cow = btrfs_alloc_tree_block(trans, root, 0, new_root_objectid,
260 &disk_key, level, buf->start, 0);
264 copy_extent_buffer(cow, buf, 0, 0, cow->len);
265 btrfs_set_header_bytenr(cow, cow->start);
266 btrfs_set_header_generation(cow, trans->transid);
267 btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV);
268 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN |
269 BTRFS_HEADER_FLAG_RELOC);
270 if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID)
271 btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC);
273 btrfs_set_header_owner(cow, new_root_objectid);
275 write_extent_buffer(cow, root->fs_info->fsid, btrfs_header_fsid(),
278 WARN_ON(btrfs_header_generation(buf) > trans->transid);
279 if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID)
280 ret = btrfs_inc_ref(trans, root, cow, 1);
282 ret = btrfs_inc_ref(trans, root, cow, 0);
287 btrfs_mark_buffer_dirty(cow);
296 MOD_LOG_KEY_REMOVE_WHILE_FREEING,
297 MOD_LOG_KEY_REMOVE_WHILE_MOVING,
299 MOD_LOG_ROOT_REPLACE,
302 struct tree_mod_move {
307 struct tree_mod_root {
312 struct tree_mod_elem {
314 u64 index; /* shifted logical */
318 /* this is used for MOD_LOG_KEY_* and MOD_LOG_MOVE_KEYS operations */
321 /* this is used for MOD_LOG_KEY* and MOD_LOG_ROOT_REPLACE */
324 /* those are used for op == MOD_LOG_KEY_{REPLACE,REMOVE} */
325 struct btrfs_disk_key key;
328 /* this is used for op == MOD_LOG_MOVE_KEYS */
329 struct tree_mod_move move;
331 /* this is used for op == MOD_LOG_ROOT_REPLACE */
332 struct tree_mod_root old_root;
335 static inline void tree_mod_log_read_lock(struct btrfs_fs_info *fs_info)
337 read_lock(&fs_info->tree_mod_log_lock);
340 static inline void tree_mod_log_read_unlock(struct btrfs_fs_info *fs_info)
342 read_unlock(&fs_info->tree_mod_log_lock);
345 static inline void tree_mod_log_write_lock(struct btrfs_fs_info *fs_info)
347 write_lock(&fs_info->tree_mod_log_lock);
350 static inline void tree_mod_log_write_unlock(struct btrfs_fs_info *fs_info)
352 write_unlock(&fs_info->tree_mod_log_lock);
356 * Pull a new tree mod seq number for our operation.
358 static inline u64 btrfs_inc_tree_mod_seq(struct btrfs_fs_info *fs_info)
360 return atomic64_inc_return(&fs_info->tree_mod_seq);
364 * This adds a new blocker to the tree mod log's blocker list if the @elem
365 * passed does not already have a sequence number set. So when a caller expects
366 * to record tree modifications, it should ensure to set elem->seq to zero
367 * before calling btrfs_get_tree_mod_seq.
368 * Returns a fresh, unused tree log modification sequence number, even if no new
371 u64 btrfs_get_tree_mod_seq(struct btrfs_fs_info *fs_info,
372 struct seq_list *elem)
374 tree_mod_log_write_lock(fs_info);
375 spin_lock(&fs_info->tree_mod_seq_lock);
377 elem->seq = btrfs_inc_tree_mod_seq(fs_info);
378 list_add_tail(&elem->list, &fs_info->tree_mod_seq_list);
380 spin_unlock(&fs_info->tree_mod_seq_lock);
381 tree_mod_log_write_unlock(fs_info);
386 void btrfs_put_tree_mod_seq(struct btrfs_fs_info *fs_info,
387 struct seq_list *elem)
389 struct rb_root *tm_root;
390 struct rb_node *node;
391 struct rb_node *next;
392 struct seq_list *cur_elem;
393 struct tree_mod_elem *tm;
394 u64 min_seq = (u64)-1;
395 u64 seq_putting = elem->seq;
400 spin_lock(&fs_info->tree_mod_seq_lock);
401 list_del(&elem->list);
404 list_for_each_entry(cur_elem, &fs_info->tree_mod_seq_list, list) {
405 if (cur_elem->seq < min_seq) {
406 if (seq_putting > cur_elem->seq) {
408 * blocker with lower sequence number exists, we
409 * cannot remove anything from the log
411 spin_unlock(&fs_info->tree_mod_seq_lock);
414 min_seq = cur_elem->seq;
417 spin_unlock(&fs_info->tree_mod_seq_lock);
420 * anything that's lower than the lowest existing (read: blocked)
421 * sequence number can be removed from the tree.
423 tree_mod_log_write_lock(fs_info);
424 tm_root = &fs_info->tree_mod_log;
425 for (node = rb_first(tm_root); node; node = next) {
426 next = rb_next(node);
427 tm = container_of(node, struct tree_mod_elem, node);
428 if (tm->seq > min_seq)
430 rb_erase(node, tm_root);
433 tree_mod_log_write_unlock(fs_info);
437 * key order of the log:
440 * the index is the shifted logical of the *new* root node for root replace
441 * operations, or the shifted logical of the affected block for all other
444 * Note: must be called with write lock (tree_mod_log_write_lock).
447 __tree_mod_log_insert(struct btrfs_fs_info *fs_info, struct tree_mod_elem *tm)
449 struct rb_root *tm_root;
450 struct rb_node **new;
451 struct rb_node *parent = NULL;
452 struct tree_mod_elem *cur;
456 tm->seq = btrfs_inc_tree_mod_seq(fs_info);
458 tm_root = &fs_info->tree_mod_log;
459 new = &tm_root->rb_node;
461 cur = container_of(*new, struct tree_mod_elem, node);
463 if (cur->index < tm->index)
464 new = &((*new)->rb_left);
465 else if (cur->index > tm->index)
466 new = &((*new)->rb_right);
467 else if (cur->seq < tm->seq)
468 new = &((*new)->rb_left);
469 else if (cur->seq > tm->seq)
470 new = &((*new)->rb_right);
475 rb_link_node(&tm->node, parent, new);
476 rb_insert_color(&tm->node, tm_root);
481 * Determines if logging can be omitted. Returns 1 if it can. Otherwise, it
482 * returns zero with the tree_mod_log_lock acquired. The caller must hold
483 * this until all tree mod log insertions are recorded in the rb tree and then
484 * call tree_mod_log_write_unlock() to release.
486 static inline int tree_mod_dont_log(struct btrfs_fs_info *fs_info,
487 struct extent_buffer *eb) {
489 if (list_empty(&(fs_info)->tree_mod_seq_list))
491 if (eb && btrfs_header_level(eb) == 0)
494 tree_mod_log_write_lock(fs_info);
495 if (list_empty(&(fs_info)->tree_mod_seq_list)) {
496 tree_mod_log_write_unlock(fs_info);
503 /* Similar to tree_mod_dont_log, but doesn't acquire any locks. */
504 static inline int tree_mod_need_log(const struct btrfs_fs_info *fs_info,
505 struct extent_buffer *eb)
508 if (list_empty(&(fs_info)->tree_mod_seq_list))
510 if (eb && btrfs_header_level(eb) == 0)
516 static struct tree_mod_elem *
517 alloc_tree_mod_elem(struct extent_buffer *eb, int slot,
518 enum mod_log_op op, gfp_t flags)
520 struct tree_mod_elem *tm;
522 tm = kzalloc(sizeof(*tm), flags);
526 tm->index = eb->start >> PAGE_CACHE_SHIFT;
527 if (op != MOD_LOG_KEY_ADD) {
528 btrfs_node_key(eb, &tm->key, slot);
529 tm->blockptr = btrfs_node_blockptr(eb, slot);
533 tm->generation = btrfs_node_ptr_generation(eb, slot);
534 RB_CLEAR_NODE(&tm->node);
540 tree_mod_log_insert_key(struct btrfs_fs_info *fs_info,
541 struct extent_buffer *eb, int slot,
542 enum mod_log_op op, gfp_t flags)
544 struct tree_mod_elem *tm;
547 if (!tree_mod_need_log(fs_info, eb))
550 tm = alloc_tree_mod_elem(eb, slot, op, flags);
554 if (tree_mod_dont_log(fs_info, eb)) {
559 ret = __tree_mod_log_insert(fs_info, tm);
560 tree_mod_log_write_unlock(fs_info);
568 tree_mod_log_insert_move(struct btrfs_fs_info *fs_info,
569 struct extent_buffer *eb, int dst_slot, int src_slot,
570 int nr_items, gfp_t flags)
572 struct tree_mod_elem *tm = NULL;
573 struct tree_mod_elem **tm_list = NULL;
578 if (!tree_mod_need_log(fs_info, eb))
581 tm_list = kcalloc(nr_items, sizeof(struct tree_mod_elem *), flags);
585 tm = kzalloc(sizeof(*tm), flags);
591 tm->index = eb->start >> PAGE_CACHE_SHIFT;
593 tm->move.dst_slot = dst_slot;
594 tm->move.nr_items = nr_items;
595 tm->op = MOD_LOG_MOVE_KEYS;
597 for (i = 0; i + dst_slot < src_slot && i < nr_items; i++) {
598 tm_list[i] = alloc_tree_mod_elem(eb, i + dst_slot,
599 MOD_LOG_KEY_REMOVE_WHILE_MOVING, flags);
606 if (tree_mod_dont_log(fs_info, eb))
611 * When we override something during the move, we log these removals.
612 * This can only happen when we move towards the beginning of the
613 * buffer, i.e. dst_slot < src_slot.
615 for (i = 0; i + dst_slot < src_slot && i < nr_items; i++) {
616 ret = __tree_mod_log_insert(fs_info, tm_list[i]);
621 ret = __tree_mod_log_insert(fs_info, tm);
624 tree_mod_log_write_unlock(fs_info);
629 for (i = 0; i < nr_items; i++) {
630 if (tm_list[i] && !RB_EMPTY_NODE(&tm_list[i]->node))
631 rb_erase(&tm_list[i]->node, &fs_info->tree_mod_log);
635 tree_mod_log_write_unlock(fs_info);
643 __tree_mod_log_free_eb(struct btrfs_fs_info *fs_info,
644 struct tree_mod_elem **tm_list,
650 for (i = nritems - 1; i >= 0; i--) {
651 ret = __tree_mod_log_insert(fs_info, tm_list[i]);
653 for (j = nritems - 1; j > i; j--)
654 rb_erase(&tm_list[j]->node,
655 &fs_info->tree_mod_log);
664 tree_mod_log_insert_root(struct btrfs_fs_info *fs_info,
665 struct extent_buffer *old_root,
666 struct extent_buffer *new_root, gfp_t flags,
669 struct tree_mod_elem *tm = NULL;
670 struct tree_mod_elem **tm_list = NULL;
675 if (!tree_mod_need_log(fs_info, NULL))
678 if (log_removal && btrfs_header_level(old_root) > 0) {
679 nritems = btrfs_header_nritems(old_root);
680 tm_list = kcalloc(nritems, sizeof(struct tree_mod_elem *),
686 for (i = 0; i < nritems; i++) {
687 tm_list[i] = alloc_tree_mod_elem(old_root, i,
688 MOD_LOG_KEY_REMOVE_WHILE_FREEING, flags);
696 tm = kzalloc(sizeof(*tm), flags);
702 tm->index = new_root->start >> PAGE_CACHE_SHIFT;
703 tm->old_root.logical = old_root->start;
704 tm->old_root.level = btrfs_header_level(old_root);
705 tm->generation = btrfs_header_generation(old_root);
706 tm->op = MOD_LOG_ROOT_REPLACE;
708 if (tree_mod_dont_log(fs_info, NULL))
712 ret = __tree_mod_log_free_eb(fs_info, tm_list, nritems);
714 ret = __tree_mod_log_insert(fs_info, tm);
716 tree_mod_log_write_unlock(fs_info);
725 for (i = 0; i < nritems; i++)
734 static struct tree_mod_elem *
735 __tree_mod_log_search(struct btrfs_fs_info *fs_info, u64 start, u64 min_seq,
738 struct rb_root *tm_root;
739 struct rb_node *node;
740 struct tree_mod_elem *cur = NULL;
741 struct tree_mod_elem *found = NULL;
742 u64 index = start >> PAGE_CACHE_SHIFT;
744 tree_mod_log_read_lock(fs_info);
745 tm_root = &fs_info->tree_mod_log;
746 node = tm_root->rb_node;
748 cur = container_of(node, struct tree_mod_elem, node);
749 if (cur->index < index) {
750 node = node->rb_left;
751 } else if (cur->index > index) {
752 node = node->rb_right;
753 } else if (cur->seq < min_seq) {
754 node = node->rb_left;
755 } else if (!smallest) {
756 /* we want the node with the highest seq */
758 BUG_ON(found->seq > cur->seq);
760 node = node->rb_left;
761 } else if (cur->seq > min_seq) {
762 /* we want the node with the smallest seq */
764 BUG_ON(found->seq < cur->seq);
766 node = node->rb_right;
772 tree_mod_log_read_unlock(fs_info);
778 * this returns the element from the log with the smallest time sequence
779 * value that's in the log (the oldest log item). any element with a time
780 * sequence lower than min_seq will be ignored.
782 static struct tree_mod_elem *
783 tree_mod_log_search_oldest(struct btrfs_fs_info *fs_info, u64 start,
786 return __tree_mod_log_search(fs_info, start, min_seq, 1);
790 * this returns the element from the log with the largest time sequence
791 * value that's in the log (the most recent log item). any element with
792 * a time sequence lower than min_seq will be ignored.
794 static struct tree_mod_elem *
795 tree_mod_log_search(struct btrfs_fs_info *fs_info, u64 start, u64 min_seq)
797 return __tree_mod_log_search(fs_info, start, min_seq, 0);
801 tree_mod_log_eb_copy(struct btrfs_fs_info *fs_info, struct extent_buffer *dst,
802 struct extent_buffer *src, unsigned long dst_offset,
803 unsigned long src_offset, int nr_items)
806 struct tree_mod_elem **tm_list = NULL;
807 struct tree_mod_elem **tm_list_add, **tm_list_rem;
811 if (!tree_mod_need_log(fs_info, NULL))
814 if (btrfs_header_level(dst) == 0 && btrfs_header_level(src) == 0)
817 tm_list = kcalloc(nr_items * 2, sizeof(struct tree_mod_elem *),
822 tm_list_add = tm_list;
823 tm_list_rem = tm_list + nr_items;
824 for (i = 0; i < nr_items; i++) {
825 tm_list_rem[i] = alloc_tree_mod_elem(src, i + src_offset,
826 MOD_LOG_KEY_REMOVE, GFP_NOFS);
827 if (!tm_list_rem[i]) {
832 tm_list_add[i] = alloc_tree_mod_elem(dst, i + dst_offset,
833 MOD_LOG_KEY_ADD, GFP_NOFS);
834 if (!tm_list_add[i]) {
840 if (tree_mod_dont_log(fs_info, NULL))
844 for (i = 0; i < nr_items; i++) {
845 ret = __tree_mod_log_insert(fs_info, tm_list_rem[i]);
848 ret = __tree_mod_log_insert(fs_info, tm_list_add[i]);
853 tree_mod_log_write_unlock(fs_info);
859 for (i = 0; i < nr_items * 2; i++) {
860 if (tm_list[i] && !RB_EMPTY_NODE(&tm_list[i]->node))
861 rb_erase(&tm_list[i]->node, &fs_info->tree_mod_log);
865 tree_mod_log_write_unlock(fs_info);
872 tree_mod_log_eb_move(struct btrfs_fs_info *fs_info, struct extent_buffer *dst,
873 int dst_offset, int src_offset, int nr_items)
876 ret = tree_mod_log_insert_move(fs_info, dst, dst_offset, src_offset,
882 tree_mod_log_set_node_key(struct btrfs_fs_info *fs_info,
883 struct extent_buffer *eb, int slot, int atomic)
887 ret = tree_mod_log_insert_key(fs_info, eb, slot,
889 atomic ? GFP_ATOMIC : GFP_NOFS);
894 tree_mod_log_free_eb(struct btrfs_fs_info *fs_info, struct extent_buffer *eb)
896 struct tree_mod_elem **tm_list = NULL;
901 if (btrfs_header_level(eb) == 0)
904 if (!tree_mod_need_log(fs_info, NULL))
907 nritems = btrfs_header_nritems(eb);
908 tm_list = kcalloc(nritems, sizeof(struct tree_mod_elem *), GFP_NOFS);
912 for (i = 0; i < nritems; i++) {
913 tm_list[i] = alloc_tree_mod_elem(eb, i,
914 MOD_LOG_KEY_REMOVE_WHILE_FREEING, GFP_NOFS);
921 if (tree_mod_dont_log(fs_info, eb))
924 ret = __tree_mod_log_free_eb(fs_info, tm_list, nritems);
925 tree_mod_log_write_unlock(fs_info);
933 for (i = 0; i < nritems; i++)
941 tree_mod_log_set_root_pointer(struct btrfs_root *root,
942 struct extent_buffer *new_root_node,
946 ret = tree_mod_log_insert_root(root->fs_info, root->node,
947 new_root_node, GFP_NOFS, log_removal);
952 * check if the tree block can be shared by multiple trees
954 int btrfs_block_can_be_shared(struct btrfs_root *root,
955 struct extent_buffer *buf)
958 * Tree blocks not in refernece counted trees and tree roots
959 * are never shared. If a block was allocated after the last
960 * snapshot and the block was not allocated by tree relocation,
961 * we know the block is not shared.
963 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
964 buf != root->node && buf != root->commit_root &&
965 (btrfs_header_generation(buf) <=
966 btrfs_root_last_snapshot(&root->root_item) ||
967 btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)))
969 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
970 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
971 btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
977 static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans,
978 struct btrfs_root *root,
979 struct extent_buffer *buf,
980 struct extent_buffer *cow,
990 * Backrefs update rules:
992 * Always use full backrefs for extent pointers in tree block
993 * allocated by tree relocation.
995 * If a shared tree block is no longer referenced by its owner
996 * tree (btrfs_header_owner(buf) == root->root_key.objectid),
997 * use full backrefs for extent pointers in tree block.
999 * If a tree block is been relocating
1000 * (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID),
1001 * use full backrefs for extent pointers in tree block.
1002 * The reason for this is some operations (such as drop tree)
1003 * are only allowed for blocks use full backrefs.
1006 if (btrfs_block_can_be_shared(root, buf)) {
1007 ret = btrfs_lookup_extent_info(trans, root, buf->start,
1008 btrfs_header_level(buf), 1,
1014 btrfs_std_error(root->fs_info, ret, NULL);
1019 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
1020 btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
1021 flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
1026 owner = btrfs_header_owner(buf);
1027 BUG_ON(owner == BTRFS_TREE_RELOC_OBJECTID &&
1028 !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
1031 if ((owner == root->root_key.objectid ||
1032 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) &&
1033 !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) {
1034 ret = btrfs_inc_ref(trans, root, buf, 1);
1035 BUG_ON(ret); /* -ENOMEM */
1037 if (root->root_key.objectid ==
1038 BTRFS_TREE_RELOC_OBJECTID) {
1039 ret = btrfs_dec_ref(trans, root, buf, 0);
1040 BUG_ON(ret); /* -ENOMEM */
1041 ret = btrfs_inc_ref(trans, root, cow, 1);
1042 BUG_ON(ret); /* -ENOMEM */
1044 new_flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
1047 if (root->root_key.objectid ==
1048 BTRFS_TREE_RELOC_OBJECTID)
1049 ret = btrfs_inc_ref(trans, root, cow, 1);
1051 ret = btrfs_inc_ref(trans, root, cow, 0);
1052 BUG_ON(ret); /* -ENOMEM */
1054 if (new_flags != 0) {
1055 int level = btrfs_header_level(buf);
1057 ret = btrfs_set_disk_extent_flags(trans, root,
1060 new_flags, level, 0);
1065 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
1066 if (root->root_key.objectid ==
1067 BTRFS_TREE_RELOC_OBJECTID)
1068 ret = btrfs_inc_ref(trans, root, cow, 1);
1070 ret = btrfs_inc_ref(trans, root, cow, 0);
1071 BUG_ON(ret); /* -ENOMEM */
1072 ret = btrfs_dec_ref(trans, root, buf, 1);
1073 BUG_ON(ret); /* -ENOMEM */
1075 clean_tree_block(trans, root->fs_info, buf);
1082 * does the dirty work in cow of a single block. The parent block (if
1083 * supplied) is updated to point to the new cow copy. The new buffer is marked
1084 * dirty and returned locked. If you modify the block it needs to be marked
1087 * search_start -- an allocation hint for the new block
1089 * empty_size -- a hint that you plan on doing more cow. This is the size in
1090 * bytes the allocator should try to find free next to the block it returns.
1091 * This is just a hint and may be ignored by the allocator.
1093 static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
1094 struct btrfs_root *root,
1095 struct extent_buffer *buf,
1096 struct extent_buffer *parent, int parent_slot,
1097 struct extent_buffer **cow_ret,
1098 u64 search_start, u64 empty_size)
1100 struct btrfs_disk_key disk_key;
1101 struct extent_buffer *cow;
1104 int unlock_orig = 0;
1107 if (*cow_ret == buf)
1110 btrfs_assert_tree_locked(buf);
1112 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
1113 trans->transid != root->fs_info->running_transaction->transid);
1114 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
1115 trans->transid != root->last_trans);
1117 level = btrfs_header_level(buf);
1120 btrfs_item_key(buf, &disk_key, 0);
1122 btrfs_node_key(buf, &disk_key, 0);
1124 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
1126 parent_start = parent->start;
1132 cow = btrfs_alloc_tree_block(trans, root, parent_start,
1133 root->root_key.objectid, &disk_key, level,
1134 search_start, empty_size);
1136 return PTR_ERR(cow);
1138 /* cow is set to blocking by btrfs_init_new_buffer */
1140 copy_extent_buffer(cow, buf, 0, 0, cow->len);
1141 btrfs_set_header_bytenr(cow, cow->start);
1142 btrfs_set_header_generation(cow, trans->transid);
1143 btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV);
1144 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN |
1145 BTRFS_HEADER_FLAG_RELOC);
1146 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1147 btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC);
1149 btrfs_set_header_owner(cow, root->root_key.objectid);
1151 write_extent_buffer(cow, root->fs_info->fsid, btrfs_header_fsid(),
1154 ret = update_ref_for_cow(trans, root, buf, cow, &last_ref);
1156 btrfs_abort_transaction(trans, root, ret);
1160 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
1161 ret = btrfs_reloc_cow_block(trans, root, buf, cow);
1163 btrfs_abort_transaction(trans, root, ret);
1168 if (buf == root->node) {
1169 WARN_ON(parent && parent != buf);
1170 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
1171 btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
1172 parent_start = buf->start;
1176 extent_buffer_get(cow);
1177 tree_mod_log_set_root_pointer(root, cow, 1);
1178 rcu_assign_pointer(root->node, cow);
1180 btrfs_free_tree_block(trans, root, buf, parent_start,
1182 free_extent_buffer(buf);
1183 add_root_to_dirty_list(root);
1185 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1186 parent_start = parent->start;
1190 WARN_ON(trans->transid != btrfs_header_generation(parent));
1191 tree_mod_log_insert_key(root->fs_info, parent, parent_slot,
1192 MOD_LOG_KEY_REPLACE, GFP_NOFS);
1193 btrfs_set_node_blockptr(parent, parent_slot,
1195 btrfs_set_node_ptr_generation(parent, parent_slot,
1197 btrfs_mark_buffer_dirty(parent);
1199 ret = tree_mod_log_free_eb(root->fs_info, buf);
1201 btrfs_abort_transaction(trans, root, ret);
1205 btrfs_free_tree_block(trans, root, buf, parent_start,
1209 btrfs_tree_unlock(buf);
1210 free_extent_buffer_stale(buf);
1211 btrfs_mark_buffer_dirty(cow);
1217 * returns the logical address of the oldest predecessor of the given root.
1218 * entries older than time_seq are ignored.
1220 static struct tree_mod_elem *
1221 __tree_mod_log_oldest_root(struct btrfs_fs_info *fs_info,
1222 struct extent_buffer *eb_root, u64 time_seq)
1224 struct tree_mod_elem *tm;
1225 struct tree_mod_elem *found = NULL;
1226 u64 root_logical = eb_root->start;
1233 * the very last operation that's logged for a root is the replacement
1234 * operation (if it is replaced at all). this has the index of the *new*
1235 * root, making it the very first operation that's logged for this root.
1238 tm = tree_mod_log_search_oldest(fs_info, root_logical,
1243 * if there are no tree operation for the oldest root, we simply
1244 * return it. this should only happen if that (old) root is at
1251 * if there's an operation that's not a root replacement, we
1252 * found the oldest version of our root. normally, we'll find a
1253 * MOD_LOG_KEY_REMOVE_WHILE_FREEING operation here.
1255 if (tm->op != MOD_LOG_ROOT_REPLACE)
1259 root_logical = tm->old_root.logical;
1263 /* if there's no old root to return, return what we found instead */
1271 * tm is a pointer to the first operation to rewind within eb. then, all
1272 * previous operations will be rewinded (until we reach something older than
1276 __tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct extent_buffer *eb,
1277 u64 time_seq, struct tree_mod_elem *first_tm)
1280 struct rb_node *next;
1281 struct tree_mod_elem *tm = first_tm;
1282 unsigned long o_dst;
1283 unsigned long o_src;
1284 unsigned long p_size = sizeof(struct btrfs_key_ptr);
1286 n = btrfs_header_nritems(eb);
1287 tree_mod_log_read_lock(fs_info);
1288 while (tm && tm->seq >= time_seq) {
1290 * all the operations are recorded with the operator used for
1291 * the modification. as we're going backwards, we do the
1292 * opposite of each operation here.
1295 case MOD_LOG_KEY_REMOVE_WHILE_FREEING:
1296 BUG_ON(tm->slot < n);
1298 case MOD_LOG_KEY_REMOVE_WHILE_MOVING:
1299 case MOD_LOG_KEY_REMOVE:
1300 btrfs_set_node_key(eb, &tm->key, tm->slot);
1301 btrfs_set_node_blockptr(eb, tm->slot, tm->blockptr);
1302 btrfs_set_node_ptr_generation(eb, tm->slot,
1306 case MOD_LOG_KEY_REPLACE:
1307 BUG_ON(tm->slot >= n);
1308 btrfs_set_node_key(eb, &tm->key, tm->slot);
1309 btrfs_set_node_blockptr(eb, tm->slot, tm->blockptr);
1310 btrfs_set_node_ptr_generation(eb, tm->slot,
1313 case MOD_LOG_KEY_ADD:
1314 /* if a move operation is needed it's in the log */
1317 case MOD_LOG_MOVE_KEYS:
1318 o_dst = btrfs_node_key_ptr_offset(tm->slot);
1319 o_src = btrfs_node_key_ptr_offset(tm->move.dst_slot);
1320 memmove_extent_buffer(eb, o_dst, o_src,
1321 tm->move.nr_items * p_size);
1323 case MOD_LOG_ROOT_REPLACE:
1325 * this operation is special. for roots, this must be
1326 * handled explicitly before rewinding.
1327 * for non-roots, this operation may exist if the node
1328 * was a root: root A -> child B; then A gets empty and
1329 * B is promoted to the new root. in the mod log, we'll
1330 * have a root-replace operation for B, a tree block
1331 * that is no root. we simply ignore that operation.
1335 next = rb_next(&tm->node);
1338 tm = container_of(next, struct tree_mod_elem, node);
1339 if (tm->index != first_tm->index)
1342 tree_mod_log_read_unlock(fs_info);
1343 btrfs_set_header_nritems(eb, n);
1347 * Called with eb read locked. If the buffer cannot be rewinded, the same buffer
1348 * is returned. If rewind operations happen, a fresh buffer is returned. The
1349 * returned buffer is always read-locked. If the returned buffer is not the
1350 * input buffer, the lock on the input buffer is released and the input buffer
1351 * is freed (its refcount is decremented).
1353 static struct extent_buffer *
1354 tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct btrfs_path *path,
1355 struct extent_buffer *eb, u64 time_seq)
1357 struct extent_buffer *eb_rewin;
1358 struct tree_mod_elem *tm;
1363 if (btrfs_header_level(eb) == 0)
1366 tm = tree_mod_log_search(fs_info, eb->start, time_seq);
1370 btrfs_set_path_blocking(path);
1371 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
1373 if (tm->op == MOD_LOG_KEY_REMOVE_WHILE_FREEING) {
1374 BUG_ON(tm->slot != 0);
1375 eb_rewin = alloc_dummy_extent_buffer(fs_info, eb->start);
1377 btrfs_tree_read_unlock_blocking(eb);
1378 free_extent_buffer(eb);
1381 btrfs_set_header_bytenr(eb_rewin, eb->start);
1382 btrfs_set_header_backref_rev(eb_rewin,
1383 btrfs_header_backref_rev(eb));
1384 btrfs_set_header_owner(eb_rewin, btrfs_header_owner(eb));
1385 btrfs_set_header_level(eb_rewin, btrfs_header_level(eb));
1387 eb_rewin = btrfs_clone_extent_buffer(eb);
1389 btrfs_tree_read_unlock_blocking(eb);
1390 free_extent_buffer(eb);
1395 btrfs_clear_path_blocking(path, NULL, BTRFS_READ_LOCK);
1396 btrfs_tree_read_unlock_blocking(eb);
1397 free_extent_buffer(eb);
1399 extent_buffer_get(eb_rewin);
1400 btrfs_tree_read_lock(eb_rewin);
1401 __tree_mod_log_rewind(fs_info, eb_rewin, time_seq, tm);
1402 WARN_ON(btrfs_header_nritems(eb_rewin) >
1403 BTRFS_NODEPTRS_PER_BLOCK(fs_info->tree_root));
1409 * get_old_root() rewinds the state of @root's root node to the given @time_seq
1410 * value. If there are no changes, the current root->root_node is returned. If
1411 * anything changed in between, there's a fresh buffer allocated on which the
1412 * rewind operations are done. In any case, the returned buffer is read locked.
1413 * Returns NULL on error (with no locks held).
1415 static inline struct extent_buffer *
1416 get_old_root(struct btrfs_root *root, u64 time_seq)
1418 struct tree_mod_elem *tm;
1419 struct extent_buffer *eb = NULL;
1420 struct extent_buffer *eb_root;
1421 struct extent_buffer *old;
1422 struct tree_mod_root *old_root = NULL;
1423 u64 old_generation = 0;
1426 eb_root = btrfs_read_lock_root_node(root);
1427 tm = __tree_mod_log_oldest_root(root->fs_info, eb_root, time_seq);
1431 if (tm->op == MOD_LOG_ROOT_REPLACE) {
1432 old_root = &tm->old_root;
1433 old_generation = tm->generation;
1434 logical = old_root->logical;
1436 logical = eb_root->start;
1439 tm = tree_mod_log_search(root->fs_info, logical, time_seq);
1440 if (old_root && tm && tm->op != MOD_LOG_KEY_REMOVE_WHILE_FREEING) {
1441 btrfs_tree_read_unlock(eb_root);
1442 free_extent_buffer(eb_root);
1443 old = read_tree_block(root, logical, 0);
1444 if (WARN_ON(IS_ERR(old) || !extent_buffer_uptodate(old))) {
1446 free_extent_buffer(old);
1447 btrfs_warn(root->fs_info,
1448 "failed to read tree block %llu from get_old_root", logical);
1450 eb = btrfs_clone_extent_buffer(old);
1451 free_extent_buffer(old);
1453 } else if (old_root) {
1454 btrfs_tree_read_unlock(eb_root);
1455 free_extent_buffer(eb_root);
1456 eb = alloc_dummy_extent_buffer(root->fs_info, logical);
1458 btrfs_set_lock_blocking_rw(eb_root, BTRFS_READ_LOCK);
1459 eb = btrfs_clone_extent_buffer(eb_root);
1460 btrfs_tree_read_unlock_blocking(eb_root);
1461 free_extent_buffer(eb_root);
1466 extent_buffer_get(eb);
1467 btrfs_tree_read_lock(eb);
1469 btrfs_set_header_bytenr(eb, eb->start);
1470 btrfs_set_header_backref_rev(eb, BTRFS_MIXED_BACKREF_REV);
1471 btrfs_set_header_owner(eb, btrfs_header_owner(eb_root));
1472 btrfs_set_header_level(eb, old_root->level);
1473 btrfs_set_header_generation(eb, old_generation);
1476 __tree_mod_log_rewind(root->fs_info, eb, time_seq, tm);
1478 WARN_ON(btrfs_header_level(eb) != 0);
1479 WARN_ON(btrfs_header_nritems(eb) > BTRFS_NODEPTRS_PER_BLOCK(root));
1484 int btrfs_old_root_level(struct btrfs_root *root, u64 time_seq)
1486 struct tree_mod_elem *tm;
1488 struct extent_buffer *eb_root = btrfs_root_node(root);
1490 tm = __tree_mod_log_oldest_root(root->fs_info, eb_root, time_seq);
1491 if (tm && tm->op == MOD_LOG_ROOT_REPLACE) {
1492 level = tm->old_root.level;
1494 level = btrfs_header_level(eb_root);
1496 free_extent_buffer(eb_root);
1501 static inline int should_cow_block(struct btrfs_trans_handle *trans,
1502 struct btrfs_root *root,
1503 struct extent_buffer *buf)
1505 if (btrfs_test_is_dummy_root(root))
1508 /* ensure we can see the force_cow */
1512 * We do not need to cow a block if
1513 * 1) this block is not created or changed in this transaction;
1514 * 2) this block does not belong to TREE_RELOC tree;
1515 * 3) the root is not forced COW.
1517 * What is forced COW:
1518 * when we create snapshot during commiting the transaction,
1519 * after we've finished coping src root, we must COW the shared
1520 * block to ensure the metadata consistency.
1522 if (btrfs_header_generation(buf) == trans->transid &&
1523 !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN) &&
1524 !(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID &&
1525 btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)) &&
1526 !test_bit(BTRFS_ROOT_FORCE_COW, &root->state))
1532 * cows a single block, see __btrfs_cow_block for the real work.
1533 * This version of it has extra checks so that a block isn't cow'd more than
1534 * once per transaction, as long as it hasn't been written yet
1536 noinline int btrfs_cow_block(struct btrfs_trans_handle *trans,
1537 struct btrfs_root *root, struct extent_buffer *buf,
1538 struct extent_buffer *parent, int parent_slot,
1539 struct extent_buffer **cow_ret)
1544 if (trans->transaction != root->fs_info->running_transaction)
1545 WARN(1, KERN_CRIT "trans %llu running %llu\n",
1547 root->fs_info->running_transaction->transid);
1549 if (trans->transid != root->fs_info->generation)
1550 WARN(1, KERN_CRIT "trans %llu running %llu\n",
1551 trans->transid, root->fs_info->generation);
1553 if (!should_cow_block(trans, root, buf)) {
1554 trans->dirty = true;
1559 search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1);
1562 btrfs_set_lock_blocking(parent);
1563 btrfs_set_lock_blocking(buf);
1565 ret = __btrfs_cow_block(trans, root, buf, parent,
1566 parent_slot, cow_ret, search_start, 0);
1568 trace_btrfs_cow_block(root, buf, *cow_ret);
1574 * helper function for defrag to decide if two blocks pointed to by a
1575 * node are actually close by
1577 static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
1579 if (blocknr < other && other - (blocknr + blocksize) < 32768)
1581 if (blocknr > other && blocknr - (other + blocksize) < 32768)
1587 * compare two keys in a memcmp fashion
1589 static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
1591 struct btrfs_key k1;
1593 btrfs_disk_key_to_cpu(&k1, disk);
1595 return btrfs_comp_cpu_keys(&k1, k2);
1599 * same as comp_keys only with two btrfs_key's
1601 int btrfs_comp_cpu_keys(struct btrfs_key *k1, struct btrfs_key *k2)
1603 if (k1->objectid > k2->objectid)
1605 if (k1->objectid < k2->objectid)
1607 if (k1->type > k2->type)
1609 if (k1->type < k2->type)
1611 if (k1->offset > k2->offset)
1613 if (k1->offset < k2->offset)
1619 * this is used by the defrag code to go through all the
1620 * leaves pointed to by a node and reallocate them so that
1621 * disk order is close to key order
1623 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
1624 struct btrfs_root *root, struct extent_buffer *parent,
1625 int start_slot, u64 *last_ret,
1626 struct btrfs_key *progress)
1628 struct extent_buffer *cur;
1631 u64 search_start = *last_ret;
1641 int progress_passed = 0;
1642 struct btrfs_disk_key disk_key;
1644 parent_level = btrfs_header_level(parent);
1646 WARN_ON(trans->transaction != root->fs_info->running_transaction);
1647 WARN_ON(trans->transid != root->fs_info->generation);
1649 parent_nritems = btrfs_header_nritems(parent);
1650 blocksize = root->nodesize;
1651 end_slot = parent_nritems - 1;
1653 if (parent_nritems <= 1)
1656 btrfs_set_lock_blocking(parent);
1658 for (i = start_slot; i <= end_slot; i++) {
1661 btrfs_node_key(parent, &disk_key, i);
1662 if (!progress_passed && comp_keys(&disk_key, progress) < 0)
1665 progress_passed = 1;
1666 blocknr = btrfs_node_blockptr(parent, i);
1667 gen = btrfs_node_ptr_generation(parent, i);
1668 if (last_block == 0)
1669 last_block = blocknr;
1672 other = btrfs_node_blockptr(parent, i - 1);
1673 close = close_blocks(blocknr, other, blocksize);
1675 if (!close && i < end_slot) {
1676 other = btrfs_node_blockptr(parent, i + 1);
1677 close = close_blocks(blocknr, other, blocksize);
1680 last_block = blocknr;
1684 cur = btrfs_find_tree_block(root->fs_info, blocknr);
1686 uptodate = btrfs_buffer_uptodate(cur, gen, 0);
1689 if (!cur || !uptodate) {
1691 cur = read_tree_block(root, blocknr, gen);
1693 return PTR_ERR(cur);
1694 } else if (!extent_buffer_uptodate(cur)) {
1695 free_extent_buffer(cur);
1698 } else if (!uptodate) {
1699 err = btrfs_read_buffer(cur, gen);
1701 free_extent_buffer(cur);
1706 if (search_start == 0)
1707 search_start = last_block;
1709 btrfs_tree_lock(cur);
1710 btrfs_set_lock_blocking(cur);
1711 err = __btrfs_cow_block(trans, root, cur, parent, i,
1714 (end_slot - i) * blocksize));
1716 btrfs_tree_unlock(cur);
1717 free_extent_buffer(cur);
1720 search_start = cur->start;
1721 last_block = cur->start;
1722 *last_ret = search_start;
1723 btrfs_tree_unlock(cur);
1724 free_extent_buffer(cur);
1730 * The leaf data grows from end-to-front in the node.
1731 * this returns the address of the start of the last item,
1732 * which is the stop of the leaf data stack
1734 static inline unsigned int leaf_data_end(struct btrfs_root *root,
1735 struct extent_buffer *leaf)
1737 u32 nr = btrfs_header_nritems(leaf);
1739 return BTRFS_LEAF_DATA_SIZE(root);
1740 return btrfs_item_offset_nr(leaf, nr - 1);
1745 * search for key in the extent_buffer. The items start at offset p,
1746 * and they are item_size apart. There are 'max' items in p.
1748 * the slot in the array is returned via slot, and it points to
1749 * the place where you would insert key if it is not found in
1752 * slot may point to max if the key is bigger than all of the keys
1754 static noinline int generic_bin_search(struct extent_buffer *eb,
1756 int item_size, struct btrfs_key *key,
1763 struct btrfs_disk_key *tmp = NULL;
1764 struct btrfs_disk_key unaligned;
1765 unsigned long offset;
1767 unsigned long map_start = 0;
1768 unsigned long map_len = 0;
1771 while (low < high) {
1772 mid = (low + high) / 2;
1773 offset = p + mid * item_size;
1775 if (!kaddr || offset < map_start ||
1776 (offset + sizeof(struct btrfs_disk_key)) >
1777 map_start + map_len) {
1779 err = map_private_extent_buffer(eb, offset,
1780 sizeof(struct btrfs_disk_key),
1781 &kaddr, &map_start, &map_len);
1784 tmp = (struct btrfs_disk_key *)(kaddr + offset -
1787 read_extent_buffer(eb, &unaligned,
1788 offset, sizeof(unaligned));
1793 tmp = (struct btrfs_disk_key *)(kaddr + offset -
1796 ret = comp_keys(tmp, key);
1812 * simple bin_search frontend that does the right thing for
1815 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
1816 int level, int *slot)
1819 return generic_bin_search(eb,
1820 offsetof(struct btrfs_leaf, items),
1821 sizeof(struct btrfs_item),
1822 key, btrfs_header_nritems(eb),
1825 return generic_bin_search(eb,
1826 offsetof(struct btrfs_node, ptrs),
1827 sizeof(struct btrfs_key_ptr),
1828 key, btrfs_header_nritems(eb),
1832 int btrfs_bin_search(struct extent_buffer *eb, struct btrfs_key *key,
1833 int level, int *slot)
1835 return bin_search(eb, key, level, slot);
1838 static void root_add_used(struct btrfs_root *root, u32 size)
1840 spin_lock(&root->accounting_lock);
1841 btrfs_set_root_used(&root->root_item,
1842 btrfs_root_used(&root->root_item) + size);
1843 spin_unlock(&root->accounting_lock);
1846 static void root_sub_used(struct btrfs_root *root, u32 size)
1848 spin_lock(&root->accounting_lock);
1849 btrfs_set_root_used(&root->root_item,
1850 btrfs_root_used(&root->root_item) - size);
1851 spin_unlock(&root->accounting_lock);
1854 /* given a node and slot number, this reads the blocks it points to. The
1855 * extent buffer is returned with a reference taken (but unlocked).
1856 * NULL is returned on error.
1858 static noinline struct extent_buffer *read_node_slot(struct btrfs_root *root,
1859 struct extent_buffer *parent, int slot)
1861 int level = btrfs_header_level(parent);
1862 struct extent_buffer *eb;
1866 if (slot >= btrfs_header_nritems(parent))
1871 eb = read_tree_block(root, btrfs_node_blockptr(parent, slot),
1872 btrfs_node_ptr_generation(parent, slot));
1873 if (IS_ERR(eb) || !extent_buffer_uptodate(eb)) {
1875 free_extent_buffer(eb);
1883 * node level balancing, used to make sure nodes are in proper order for
1884 * item deletion. We balance from the top down, so we have to make sure
1885 * that a deletion won't leave an node completely empty later on.
1887 static noinline int balance_level(struct btrfs_trans_handle *trans,
1888 struct btrfs_root *root,
1889 struct btrfs_path *path, int level)
1891 struct extent_buffer *right = NULL;
1892 struct extent_buffer *mid;
1893 struct extent_buffer *left = NULL;
1894 struct extent_buffer *parent = NULL;
1898 int orig_slot = path->slots[level];
1904 mid = path->nodes[level];
1906 WARN_ON(path->locks[level] != BTRFS_WRITE_LOCK &&
1907 path->locks[level] != BTRFS_WRITE_LOCK_BLOCKING);
1908 WARN_ON(btrfs_header_generation(mid) != trans->transid);
1910 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
1912 if (level < BTRFS_MAX_LEVEL - 1) {
1913 parent = path->nodes[level + 1];
1914 pslot = path->slots[level + 1];
1918 * deal with the case where there is only one pointer in the root
1919 * by promoting the node below to a root
1922 struct extent_buffer *child;
1924 if (btrfs_header_nritems(mid) != 1)
1927 /* promote the child to a root */
1928 child = read_node_slot(root, mid, 0);
1931 btrfs_std_error(root->fs_info, ret, NULL);
1935 btrfs_tree_lock(child);
1936 btrfs_set_lock_blocking(child);
1937 ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
1939 btrfs_tree_unlock(child);
1940 free_extent_buffer(child);
1944 tree_mod_log_set_root_pointer(root, child, 1);
1945 rcu_assign_pointer(root->node, child);
1947 add_root_to_dirty_list(root);
1948 btrfs_tree_unlock(child);
1950 path->locks[level] = 0;
1951 path->nodes[level] = NULL;
1952 clean_tree_block(trans, root->fs_info, mid);
1953 btrfs_tree_unlock(mid);
1954 /* once for the path */
1955 free_extent_buffer(mid);
1957 root_sub_used(root, mid->len);
1958 btrfs_free_tree_block(trans, root, mid, 0, 1);
1959 /* once for the root ptr */
1960 free_extent_buffer_stale(mid);
1963 if (btrfs_header_nritems(mid) >
1964 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
1967 left = read_node_slot(root, parent, pslot - 1);
1969 btrfs_tree_lock(left);
1970 btrfs_set_lock_blocking(left);
1971 wret = btrfs_cow_block(trans, root, left,
1972 parent, pslot - 1, &left);
1978 right = read_node_slot(root, parent, pslot + 1);
1980 btrfs_tree_lock(right);
1981 btrfs_set_lock_blocking(right);
1982 wret = btrfs_cow_block(trans, root, right,
1983 parent, pslot + 1, &right);
1990 /* first, try to make some room in the middle buffer */
1992 orig_slot += btrfs_header_nritems(left);
1993 wret = push_node_left(trans, root, left, mid, 1);
1999 * then try to empty the right most buffer into the middle
2002 wret = push_node_left(trans, root, mid, right, 1);
2003 if (wret < 0 && wret != -ENOSPC)
2005 if (btrfs_header_nritems(right) == 0) {
2006 clean_tree_block(trans, root->fs_info, right);
2007 btrfs_tree_unlock(right);
2008 del_ptr(root, path, level + 1, pslot + 1);
2009 root_sub_used(root, right->len);
2010 btrfs_free_tree_block(trans, root, right, 0, 1);
2011 free_extent_buffer_stale(right);
2014 struct btrfs_disk_key right_key;
2015 btrfs_node_key(right, &right_key, 0);
2016 tree_mod_log_set_node_key(root->fs_info, parent,
2018 btrfs_set_node_key(parent, &right_key, pslot + 1);
2019 btrfs_mark_buffer_dirty(parent);
2022 if (btrfs_header_nritems(mid) == 1) {
2024 * we're not allowed to leave a node with one item in the
2025 * tree during a delete. A deletion from lower in the tree
2026 * could try to delete the only pointer in this node.
2027 * So, pull some keys from the left.
2028 * There has to be a left pointer at this point because
2029 * otherwise we would have pulled some pointers from the
2034 btrfs_std_error(root->fs_info, ret, NULL);
2037 wret = balance_node_right(trans, root, mid, left);
2043 wret = push_node_left(trans, root, left, mid, 1);
2049 if (btrfs_header_nritems(mid) == 0) {
2050 clean_tree_block(trans, root->fs_info, mid);
2051 btrfs_tree_unlock(mid);
2052 del_ptr(root, path, level + 1, pslot);
2053 root_sub_used(root, mid->len);
2054 btrfs_free_tree_block(trans, root, mid, 0, 1);
2055 free_extent_buffer_stale(mid);
2058 /* update the parent key to reflect our changes */
2059 struct btrfs_disk_key mid_key;
2060 btrfs_node_key(mid, &mid_key, 0);
2061 tree_mod_log_set_node_key(root->fs_info, parent,
2063 btrfs_set_node_key(parent, &mid_key, pslot);
2064 btrfs_mark_buffer_dirty(parent);
2067 /* update the path */
2069 if (btrfs_header_nritems(left) > orig_slot) {
2070 extent_buffer_get(left);
2071 /* left was locked after cow */
2072 path->nodes[level] = left;
2073 path->slots[level + 1] -= 1;
2074 path->slots[level] = orig_slot;
2076 btrfs_tree_unlock(mid);
2077 free_extent_buffer(mid);
2080 orig_slot -= btrfs_header_nritems(left);
2081 path->slots[level] = orig_slot;
2084 /* double check we haven't messed things up */
2086 btrfs_node_blockptr(path->nodes[level], path->slots[level]))
2090 btrfs_tree_unlock(right);
2091 free_extent_buffer(right);
2094 if (path->nodes[level] != left)
2095 btrfs_tree_unlock(left);
2096 free_extent_buffer(left);
2101 /* Node balancing for insertion. Here we only split or push nodes around
2102 * when they are completely full. This is also done top down, so we
2103 * have to be pessimistic.
2105 static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
2106 struct btrfs_root *root,
2107 struct btrfs_path *path, int level)
2109 struct extent_buffer *right = NULL;
2110 struct extent_buffer *mid;
2111 struct extent_buffer *left = NULL;
2112 struct extent_buffer *parent = NULL;
2116 int orig_slot = path->slots[level];
2121 mid = path->nodes[level];
2122 WARN_ON(btrfs_header_generation(mid) != trans->transid);
2124 if (level < BTRFS_MAX_LEVEL - 1) {
2125 parent = path->nodes[level + 1];
2126 pslot = path->slots[level + 1];
2132 left = read_node_slot(root, parent, pslot - 1);
2134 /* first, try to make some room in the middle buffer */
2138 btrfs_tree_lock(left);
2139 btrfs_set_lock_blocking(left);
2141 left_nr = btrfs_header_nritems(left);
2142 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
2145 ret = btrfs_cow_block(trans, root, left, parent,
2150 wret = push_node_left(trans, root,
2157 struct btrfs_disk_key disk_key;
2158 orig_slot += left_nr;
2159 btrfs_node_key(mid, &disk_key, 0);
2160 tree_mod_log_set_node_key(root->fs_info, parent,
2162 btrfs_set_node_key(parent, &disk_key, pslot);
2163 btrfs_mark_buffer_dirty(parent);
2164 if (btrfs_header_nritems(left) > orig_slot) {
2165 path->nodes[level] = left;
2166 path->slots[level + 1] -= 1;
2167 path->slots[level] = orig_slot;
2168 btrfs_tree_unlock(mid);
2169 free_extent_buffer(mid);
2172 btrfs_header_nritems(left);
2173 path->slots[level] = orig_slot;
2174 btrfs_tree_unlock(left);
2175 free_extent_buffer(left);
2179 btrfs_tree_unlock(left);
2180 free_extent_buffer(left);
2182 right = read_node_slot(root, parent, pslot + 1);
2185 * then try to empty the right most buffer into the middle
2190 btrfs_tree_lock(right);
2191 btrfs_set_lock_blocking(right);
2193 right_nr = btrfs_header_nritems(right);
2194 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
2197 ret = btrfs_cow_block(trans, root, right,
2203 wret = balance_node_right(trans, root,
2210 struct btrfs_disk_key disk_key;
2212 btrfs_node_key(right, &disk_key, 0);
2213 tree_mod_log_set_node_key(root->fs_info, parent,
2215 btrfs_set_node_key(parent, &disk_key, pslot + 1);
2216 btrfs_mark_buffer_dirty(parent);
2218 if (btrfs_header_nritems(mid) <= orig_slot) {
2219 path->nodes[level] = right;
2220 path->slots[level + 1] += 1;
2221 path->slots[level] = orig_slot -
2222 btrfs_header_nritems(mid);
2223 btrfs_tree_unlock(mid);
2224 free_extent_buffer(mid);
2226 btrfs_tree_unlock(right);
2227 free_extent_buffer(right);
2231 btrfs_tree_unlock(right);
2232 free_extent_buffer(right);
2238 * readahead one full node of leaves, finding things that are close
2239 * to the block in 'slot', and triggering ra on them.
2241 static void reada_for_search(struct btrfs_root *root,
2242 struct btrfs_path *path,
2243 int level, int slot, u64 objectid)
2245 struct extent_buffer *node;
2246 struct btrfs_disk_key disk_key;
2252 int direction = path->reada;
2253 struct extent_buffer *eb;
2261 if (!path->nodes[level])
2264 node = path->nodes[level];
2266 search = btrfs_node_blockptr(node, slot);
2267 blocksize = root->nodesize;
2268 eb = btrfs_find_tree_block(root->fs_info, search);
2270 free_extent_buffer(eb);
2276 nritems = btrfs_header_nritems(node);
2280 if (direction < 0) {
2284 } else if (direction > 0) {
2289 if (path->reada < 0 && objectid) {
2290 btrfs_node_key(node, &disk_key, nr);
2291 if (btrfs_disk_key_objectid(&disk_key) != objectid)
2294 search = btrfs_node_blockptr(node, nr);
2295 if ((search <= target && target - search <= 65536) ||
2296 (search > target && search - target <= 65536)) {
2297 gen = btrfs_node_ptr_generation(node, nr);
2298 readahead_tree_block(root, search);
2302 if ((nread > 65536 || nscan > 32))
2307 static noinline void reada_for_balance(struct btrfs_root *root,
2308 struct btrfs_path *path, int level)
2312 struct extent_buffer *parent;
2313 struct extent_buffer *eb;
2318 parent = path->nodes[level + 1];
2322 nritems = btrfs_header_nritems(parent);
2323 slot = path->slots[level + 1];
2326 block1 = btrfs_node_blockptr(parent, slot - 1);
2327 gen = btrfs_node_ptr_generation(parent, slot - 1);
2328 eb = btrfs_find_tree_block(root->fs_info, block1);
2330 * if we get -eagain from btrfs_buffer_uptodate, we
2331 * don't want to return eagain here. That will loop
2334 if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0)
2336 free_extent_buffer(eb);
2338 if (slot + 1 < nritems) {
2339 block2 = btrfs_node_blockptr(parent, slot + 1);
2340 gen = btrfs_node_ptr_generation(parent, slot + 1);
2341 eb = btrfs_find_tree_block(root->fs_info, block2);
2342 if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0)
2344 free_extent_buffer(eb);
2348 readahead_tree_block(root, block1);
2350 readahead_tree_block(root, block2);
2355 * when we walk down the tree, it is usually safe to unlock the higher layers
2356 * in the tree. The exceptions are when our path goes through slot 0, because
2357 * operations on the tree might require changing key pointers higher up in the
2360 * callers might also have set path->keep_locks, which tells this code to keep
2361 * the lock if the path points to the last slot in the block. This is part of
2362 * walking through the tree, and selecting the next slot in the higher block.
2364 * lowest_unlock sets the lowest level in the tree we're allowed to unlock. so
2365 * if lowest_unlock is 1, level 0 won't be unlocked
2367 static noinline void unlock_up(struct btrfs_path *path, int level,
2368 int lowest_unlock, int min_write_lock_level,
2369 int *write_lock_level)
2372 int skip_level = level;
2374 struct extent_buffer *t;
2376 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
2377 if (!path->nodes[i])
2379 if (!path->locks[i])
2381 if (!no_skips && path->slots[i] == 0) {
2385 if (!no_skips && path->keep_locks) {
2388 nritems = btrfs_header_nritems(t);
2389 if (nritems < 1 || path->slots[i] >= nritems - 1) {
2394 if (skip_level < i && i >= lowest_unlock)
2398 if (i >= lowest_unlock && i > skip_level && path->locks[i]) {
2399 btrfs_tree_unlock_rw(t, path->locks[i]);
2401 if (write_lock_level &&
2402 i > min_write_lock_level &&
2403 i <= *write_lock_level) {
2404 *write_lock_level = i - 1;
2411 * This releases any locks held in the path starting at level and
2412 * going all the way up to the root.
2414 * btrfs_search_slot will keep the lock held on higher nodes in a few
2415 * corner cases, such as COW of the block at slot zero in the node. This
2416 * ignores those rules, and it should only be called when there are no
2417 * more updates to be done higher up in the tree.
2419 noinline void btrfs_unlock_up_safe(struct btrfs_path *path, int level)
2423 if (path->keep_locks)
2426 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
2427 if (!path->nodes[i])
2429 if (!path->locks[i])
2431 btrfs_tree_unlock_rw(path->nodes[i], path->locks[i]);
2437 * helper function for btrfs_search_slot. The goal is to find a block
2438 * in cache without setting the path to blocking. If we find the block
2439 * we return zero and the path is unchanged.
2441 * If we can't find the block, we set the path blocking and do some
2442 * reada. -EAGAIN is returned and the search must be repeated.
2445 read_block_for_search(struct btrfs_trans_handle *trans,
2446 struct btrfs_root *root, struct btrfs_path *p,
2447 struct extent_buffer **eb_ret, int level, int slot,
2448 struct btrfs_key *key, u64 time_seq)
2452 struct extent_buffer *b = *eb_ret;
2453 struct extent_buffer *tmp;
2456 blocknr = btrfs_node_blockptr(b, slot);
2457 gen = btrfs_node_ptr_generation(b, slot);
2459 tmp = btrfs_find_tree_block(root->fs_info, blocknr);
2461 /* first we do an atomic uptodate check */
2462 if (btrfs_buffer_uptodate(tmp, gen, 1) > 0) {
2467 /* the pages were up to date, but we failed
2468 * the generation number check. Do a full
2469 * read for the generation number that is correct.
2470 * We must do this without dropping locks so
2471 * we can trust our generation number
2473 btrfs_set_path_blocking(p);
2475 /* now we're allowed to do a blocking uptodate check */
2476 ret = btrfs_read_buffer(tmp, gen);
2481 free_extent_buffer(tmp);
2482 btrfs_release_path(p);
2487 * reduce lock contention at high levels
2488 * of the btree by dropping locks before
2489 * we read. Don't release the lock on the current
2490 * level because we need to walk this node to figure
2491 * out which blocks to read.
2493 btrfs_unlock_up_safe(p, level + 1);
2494 btrfs_set_path_blocking(p);
2496 free_extent_buffer(tmp);
2498 reada_for_search(root, p, level, slot, key->objectid);
2500 btrfs_release_path(p);
2503 tmp = read_tree_block(root, blocknr, 0);
2506 * If the read above didn't mark this buffer up to date,
2507 * it will never end up being up to date. Set ret to EIO now
2508 * and give up so that our caller doesn't loop forever
2511 if (!btrfs_buffer_uptodate(tmp, 0, 0))
2513 free_extent_buffer(tmp);
2519 * helper function for btrfs_search_slot. This does all of the checks
2520 * for node-level blocks and does any balancing required based on
2523 * If no extra work was required, zero is returned. If we had to
2524 * drop the path, -EAGAIN is returned and btrfs_search_slot must
2528 setup_nodes_for_search(struct btrfs_trans_handle *trans,
2529 struct btrfs_root *root, struct btrfs_path *p,
2530 struct extent_buffer *b, int level, int ins_len,
2531 int *write_lock_level)
2534 if ((p->search_for_split || ins_len > 0) && btrfs_header_nritems(b) >=
2535 BTRFS_NODEPTRS_PER_BLOCK(root) - 3) {
2538 if (*write_lock_level < level + 1) {
2539 *write_lock_level = level + 1;
2540 btrfs_release_path(p);
2544 btrfs_set_path_blocking(p);
2545 reada_for_balance(root, p, level);
2546 sret = split_node(trans, root, p, level);
2547 btrfs_clear_path_blocking(p, NULL, 0);
2554 b = p->nodes[level];
2555 } else if (ins_len < 0 && btrfs_header_nritems(b) <
2556 BTRFS_NODEPTRS_PER_BLOCK(root) / 2) {
2559 if (*write_lock_level < level + 1) {
2560 *write_lock_level = level + 1;
2561 btrfs_release_path(p);
2565 btrfs_set_path_blocking(p);
2566 reada_for_balance(root, p, level);
2567 sret = balance_level(trans, root, p, level);
2568 btrfs_clear_path_blocking(p, NULL, 0);
2574 b = p->nodes[level];
2576 btrfs_release_path(p);
2579 BUG_ON(btrfs_header_nritems(b) == 1);
2589 static void key_search_validate(struct extent_buffer *b,
2590 struct btrfs_key *key,
2593 #ifdef CONFIG_BTRFS_ASSERT
2594 struct btrfs_disk_key disk_key;
2596 btrfs_cpu_key_to_disk(&disk_key, key);
2599 ASSERT(!memcmp_extent_buffer(b, &disk_key,
2600 offsetof(struct btrfs_leaf, items[0].key),
2603 ASSERT(!memcmp_extent_buffer(b, &disk_key,
2604 offsetof(struct btrfs_node, ptrs[0].key),
2609 static int key_search(struct extent_buffer *b, struct btrfs_key *key,
2610 int level, int *prev_cmp, int *slot)
2612 if (*prev_cmp != 0) {
2613 *prev_cmp = bin_search(b, key, level, slot);
2617 key_search_validate(b, key, level);
2623 int btrfs_find_item(struct btrfs_root *fs_root, struct btrfs_path *path,
2624 u64 iobjectid, u64 ioff, u8 key_type,
2625 struct btrfs_key *found_key)
2628 struct btrfs_key key;
2629 struct extent_buffer *eb;
2634 key.type = key_type;
2635 key.objectid = iobjectid;
2638 ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
2642 eb = path->nodes[0];
2643 if (ret && path->slots[0] >= btrfs_header_nritems(eb)) {
2644 ret = btrfs_next_leaf(fs_root, path);
2647 eb = path->nodes[0];
2650 btrfs_item_key_to_cpu(eb, found_key, path->slots[0]);
2651 if (found_key->type != key.type ||
2652 found_key->objectid != key.objectid)
2659 * look for key in the tree. path is filled in with nodes along the way
2660 * if key is found, we return zero and you can find the item in the leaf
2661 * level of the path (level 0)
2663 * If the key isn't found, the path points to the slot where it should
2664 * be inserted, and 1 is returned. If there are other errors during the
2665 * search a negative error number is returned.
2667 * if ins_len > 0, nodes and leaves will be split as we walk down the
2668 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
2671 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
2672 *root, struct btrfs_key *key, struct btrfs_path *p, int
2675 struct extent_buffer *b;
2680 int lowest_unlock = 1;
2682 /* everything at write_lock_level or lower must be write locked */
2683 int write_lock_level = 0;
2684 u8 lowest_level = 0;
2685 int min_write_lock_level;
2688 lowest_level = p->lowest_level;
2689 WARN_ON(lowest_level && ins_len > 0);
2690 WARN_ON(p->nodes[0] != NULL);
2691 BUG_ON(!cow && ins_len);
2696 /* when we are removing items, we might have to go up to level
2697 * two as we update tree pointers Make sure we keep write
2698 * for those levels as well
2700 write_lock_level = 2;
2701 } else if (ins_len > 0) {
2703 * for inserting items, make sure we have a write lock on
2704 * level 1 so we can update keys
2706 write_lock_level = 1;
2710 write_lock_level = -1;
2712 if (cow && (p->keep_locks || p->lowest_level))
2713 write_lock_level = BTRFS_MAX_LEVEL;
2715 min_write_lock_level = write_lock_level;
2720 * we try very hard to do read locks on the root
2722 root_lock = BTRFS_READ_LOCK;
2724 if (p->search_commit_root) {
2726 * the commit roots are read only
2727 * so we always do read locks
2729 if (p->need_commit_sem)
2730 down_read(&root->fs_info->commit_root_sem);
2731 b = root->commit_root;
2732 extent_buffer_get(b);
2733 level = btrfs_header_level(b);
2734 if (p->need_commit_sem)
2735 up_read(&root->fs_info->commit_root_sem);
2736 if (!p->skip_locking)
2737 btrfs_tree_read_lock(b);
2739 if (p->skip_locking) {
2740 b = btrfs_root_node(root);
2741 level = btrfs_header_level(b);
2743 /* we don't know the level of the root node
2744 * until we actually have it read locked
2746 b = btrfs_read_lock_root_node(root);
2747 level = btrfs_header_level(b);
2748 if (level <= write_lock_level) {
2749 /* whoops, must trade for write lock */
2750 btrfs_tree_read_unlock(b);
2751 free_extent_buffer(b);
2752 b = btrfs_lock_root_node(root);
2753 root_lock = BTRFS_WRITE_LOCK;
2755 /* the level might have changed, check again */
2756 level = btrfs_header_level(b);
2760 p->nodes[level] = b;
2761 if (!p->skip_locking)
2762 p->locks[level] = root_lock;
2765 level = btrfs_header_level(b);
2768 * setup the path here so we can release it under lock
2769 * contention with the cow code
2773 * if we don't really need to cow this block
2774 * then we don't want to set the path blocking,
2775 * so we test it here
2777 if (!should_cow_block(trans, root, b)) {
2778 trans->dirty = true;
2783 * must have write locks on this node and the
2786 if (level > write_lock_level ||
2787 (level + 1 > write_lock_level &&
2788 level + 1 < BTRFS_MAX_LEVEL &&
2789 p->nodes[level + 1])) {
2790 write_lock_level = level + 1;
2791 btrfs_release_path(p);
2795 btrfs_set_path_blocking(p);
2796 err = btrfs_cow_block(trans, root, b,
2797 p->nodes[level + 1],
2798 p->slots[level + 1], &b);
2805 p->nodes[level] = b;
2806 btrfs_clear_path_blocking(p, NULL, 0);
2809 * we have a lock on b and as long as we aren't changing
2810 * the tree, there is no way to for the items in b to change.
2811 * It is safe to drop the lock on our parent before we
2812 * go through the expensive btree search on b.
2814 * If we're inserting or deleting (ins_len != 0), then we might
2815 * be changing slot zero, which may require changing the parent.
2816 * So, we can't drop the lock until after we know which slot
2817 * we're operating on.
2819 if (!ins_len && !p->keep_locks) {
2822 if (u < BTRFS_MAX_LEVEL && p->locks[u]) {
2823 btrfs_tree_unlock_rw(p->nodes[u], p->locks[u]);
2828 ret = key_search(b, key, level, &prev_cmp, &slot);
2832 if (ret && slot > 0) {
2836 p->slots[level] = slot;
2837 err = setup_nodes_for_search(trans, root, p, b, level,
2838 ins_len, &write_lock_level);
2845 b = p->nodes[level];
2846 slot = p->slots[level];
2849 * slot 0 is special, if we change the key
2850 * we have to update the parent pointer
2851 * which means we must have a write lock
2854 if (slot == 0 && ins_len &&
2855 write_lock_level < level + 1) {
2856 write_lock_level = level + 1;
2857 btrfs_release_path(p);
2861 unlock_up(p, level, lowest_unlock,
2862 min_write_lock_level, &write_lock_level);
2864 if (level == lowest_level) {
2870 err = read_block_for_search(trans, root, p,
2871 &b, level, slot, key, 0);
2879 if (!p->skip_locking) {
2880 level = btrfs_header_level(b);
2881 if (level <= write_lock_level) {
2882 err = btrfs_try_tree_write_lock(b);
2884 btrfs_set_path_blocking(p);
2886 btrfs_clear_path_blocking(p, b,
2889 p->locks[level] = BTRFS_WRITE_LOCK;
2891 err = btrfs_tree_read_lock_atomic(b);
2893 btrfs_set_path_blocking(p);
2894 btrfs_tree_read_lock(b);
2895 btrfs_clear_path_blocking(p, b,
2898 p->locks[level] = BTRFS_READ_LOCK;
2900 p->nodes[level] = b;
2903 p->slots[level] = slot;
2905 btrfs_leaf_free_space(root, b) < ins_len) {
2906 if (write_lock_level < 1) {
2907 write_lock_level = 1;
2908 btrfs_release_path(p);
2912 btrfs_set_path_blocking(p);
2913 err = split_leaf(trans, root, key,
2914 p, ins_len, ret == 0);
2915 btrfs_clear_path_blocking(p, NULL, 0);
2923 if (!p->search_for_split)
2924 unlock_up(p, level, lowest_unlock,
2925 min_write_lock_level, &write_lock_level);
2932 * we don't really know what they plan on doing with the path
2933 * from here on, so for now just mark it as blocking
2935 if (!p->leave_spinning)
2936 btrfs_set_path_blocking(p);
2937 if (ret < 0 && !p->skip_release_on_error)
2938 btrfs_release_path(p);
2943 * Like btrfs_search_slot, this looks for a key in the given tree. It uses the
2944 * current state of the tree together with the operations recorded in the tree
2945 * modification log to search for the key in a previous version of this tree, as
2946 * denoted by the time_seq parameter.
2948 * Naturally, there is no support for insert, delete or cow operations.
2950 * The resulting path and return value will be set up as if we called
2951 * btrfs_search_slot at that point in time with ins_len and cow both set to 0.
2953 int btrfs_search_old_slot(struct btrfs_root *root, struct btrfs_key *key,
2954 struct btrfs_path *p, u64 time_seq)
2956 struct extent_buffer *b;
2961 int lowest_unlock = 1;
2962 u8 lowest_level = 0;
2965 lowest_level = p->lowest_level;
2966 WARN_ON(p->nodes[0] != NULL);
2968 if (p->search_commit_root) {
2970 return btrfs_search_slot(NULL, root, key, p, 0, 0);
2974 b = get_old_root(root, time_seq);
2975 level = btrfs_header_level(b);
2976 p->locks[level] = BTRFS_READ_LOCK;
2979 level = btrfs_header_level(b);
2980 p->nodes[level] = b;
2981 btrfs_clear_path_blocking(p, NULL, 0);
2984 * we have a lock on b and as long as we aren't changing
2985 * the tree, there is no way to for the items in b to change.
2986 * It is safe to drop the lock on our parent before we
2987 * go through the expensive btree search on b.
2989 btrfs_unlock_up_safe(p, level + 1);
2992 * Since we can unwind eb's we want to do a real search every
2996 ret = key_search(b, key, level, &prev_cmp, &slot);
3000 if (ret && slot > 0) {
3004 p->slots[level] = slot;
3005 unlock_up(p, level, lowest_unlock, 0, NULL);
3007 if (level == lowest_level) {
3013 err = read_block_for_search(NULL, root, p, &b, level,
3014 slot, key, time_seq);
3022 level = btrfs_header_level(b);
3023 err = btrfs_tree_read_lock_atomic(b);
3025 btrfs_set_path_blocking(p);
3026 btrfs_tree_read_lock(b);
3027 btrfs_clear_path_blocking(p, b,
3030 b = tree_mod_log_rewind(root->fs_info, p, b, time_seq);
3035 p->locks[level] = BTRFS_READ_LOCK;
3036 p->nodes[level] = b;
3038 p->slots[level] = slot;
3039 unlock_up(p, level, lowest_unlock, 0, NULL);
3045 if (!p->leave_spinning)
3046 btrfs_set_path_blocking(p);
3048 btrfs_release_path(p);
3054 * helper to use instead of search slot if no exact match is needed but
3055 * instead the next or previous item should be returned.
3056 * When find_higher is true, the next higher item is returned, the next lower
3058 * When return_any and find_higher are both true, and no higher item is found,
3059 * return the next lower instead.
3060 * When return_any is true and find_higher is false, and no lower item is found,
3061 * return the next higher instead.
3062 * It returns 0 if any item is found, 1 if none is found (tree empty), and
3065 int btrfs_search_slot_for_read(struct btrfs_root *root,
3066 struct btrfs_key *key, struct btrfs_path *p,
3067 int find_higher, int return_any)
3070 struct extent_buffer *leaf;
3073 ret = btrfs_search_slot(NULL, root, key, p, 0, 0);
3077 * a return value of 1 means the path is at the position where the
3078 * item should be inserted. Normally this is the next bigger item,
3079 * but in case the previous item is the last in a leaf, path points
3080 * to the first free slot in the previous leaf, i.e. at an invalid
3086 if (p->slots[0] >= btrfs_header_nritems(leaf)) {
3087 ret = btrfs_next_leaf(root, p);
3093 * no higher item found, return the next
3098 btrfs_release_path(p);
3102 if (p->slots[0] == 0) {
3103 ret = btrfs_prev_leaf(root, p);
3108 if (p->slots[0] == btrfs_header_nritems(leaf))
3115 * no lower item found, return the next
3120 btrfs_release_path(p);
3130 * adjust the pointers going up the tree, starting at level
3131 * making sure the right key of each node is points to 'key'.
3132 * This is used after shifting pointers to the left, so it stops
3133 * fixing up pointers when a given leaf/node is not in slot 0 of the
3137 static void fixup_low_keys(struct btrfs_fs_info *fs_info,
3138 struct btrfs_path *path,
3139 struct btrfs_disk_key *key, int level)
3142 struct extent_buffer *t;
3144 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
3145 int tslot = path->slots[i];
3146 if (!path->nodes[i])
3149 tree_mod_log_set_node_key(fs_info, t, tslot, 1);
3150 btrfs_set_node_key(t, key, tslot);
3151 btrfs_mark_buffer_dirty(path->nodes[i]);
3160 * This function isn't completely safe. It's the caller's responsibility
3161 * that the new key won't break the order
3163 void btrfs_set_item_key_safe(struct btrfs_fs_info *fs_info,
3164 struct btrfs_path *path,
3165 struct btrfs_key *new_key)
3167 struct btrfs_disk_key disk_key;
3168 struct extent_buffer *eb;
3171 eb = path->nodes[0];
3172 slot = path->slots[0];
3174 btrfs_item_key(eb, &disk_key, slot - 1);
3175 BUG_ON(comp_keys(&disk_key, new_key) >= 0);
3177 if (slot < btrfs_header_nritems(eb) - 1) {
3178 btrfs_item_key(eb, &disk_key, slot + 1);
3179 BUG_ON(comp_keys(&disk_key, new_key) <= 0);
3182 btrfs_cpu_key_to_disk(&disk_key, new_key);
3183 btrfs_set_item_key(eb, &disk_key, slot);
3184 btrfs_mark_buffer_dirty(eb);
3186 fixup_low_keys(fs_info, path, &disk_key, 1);
3190 * try to push data from one node into the next node left in the
3193 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
3194 * error, and > 0 if there was no room in the left hand block.
3196 static int push_node_left(struct btrfs_trans_handle *trans,
3197 struct btrfs_root *root, struct extent_buffer *dst,
3198 struct extent_buffer *src, int empty)
3205 src_nritems = btrfs_header_nritems(src);
3206 dst_nritems = btrfs_header_nritems(dst);
3207 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
3208 WARN_ON(btrfs_header_generation(src) != trans->transid);
3209 WARN_ON(btrfs_header_generation(dst) != trans->transid);
3211 if (!empty && src_nritems <= 8)
3214 if (push_items <= 0)
3218 push_items = min(src_nritems, push_items);
3219 if (push_items < src_nritems) {
3220 /* leave at least 8 pointers in the node if
3221 * we aren't going to empty it
3223 if (src_nritems - push_items < 8) {
3224 if (push_items <= 8)
3230 push_items = min(src_nritems - 8, push_items);
3232 ret = tree_mod_log_eb_copy(root->fs_info, dst, src, dst_nritems, 0,
3235 btrfs_abort_transaction(trans, root, ret);
3238 copy_extent_buffer(dst, src,
3239 btrfs_node_key_ptr_offset(dst_nritems),
3240 btrfs_node_key_ptr_offset(0),
3241 push_items * sizeof(struct btrfs_key_ptr));
3243 if (push_items < src_nritems) {
3245 * don't call tree_mod_log_eb_move here, key removal was already
3246 * fully logged by tree_mod_log_eb_copy above.
3248 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
3249 btrfs_node_key_ptr_offset(push_items),
3250 (src_nritems - push_items) *
3251 sizeof(struct btrfs_key_ptr));
3253 btrfs_set_header_nritems(src, src_nritems - push_items);
3254 btrfs_set_header_nritems(dst, dst_nritems + push_items);
3255 btrfs_mark_buffer_dirty(src);
3256 btrfs_mark_buffer_dirty(dst);
3262 * try to push data from one node into the next node right in the
3265 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
3266 * error, and > 0 if there was no room in the right hand block.
3268 * this will only push up to 1/2 the contents of the left node over
3270 static int balance_node_right(struct btrfs_trans_handle *trans,
3271 struct btrfs_root *root,
3272 struct extent_buffer *dst,
3273 struct extent_buffer *src)
3281 WARN_ON(btrfs_header_generation(src) != trans->transid);
3282 WARN_ON(btrfs_header_generation(dst) != trans->transid);
3284 src_nritems = btrfs_header_nritems(src);
3285 dst_nritems = btrfs_header_nritems(dst);
3286 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
3287 if (push_items <= 0)
3290 if (src_nritems < 4)
3293 max_push = src_nritems / 2 + 1;
3294 /* don't try to empty the node */
3295 if (max_push >= src_nritems)
3298 if (max_push < push_items)
3299 push_items = max_push;
3301 tree_mod_log_eb_move(root->fs_info, dst, push_items, 0, dst_nritems);
3302 memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
3303 btrfs_node_key_ptr_offset(0),
3305 sizeof(struct btrfs_key_ptr));
3307 ret = tree_mod_log_eb_copy(root->fs_info, dst, src, 0,
3308 src_nritems - push_items, push_items);
3310 btrfs_abort_transaction(trans, root, ret);
3313 copy_extent_buffer(dst, src,
3314 btrfs_node_key_ptr_offset(0),
3315 btrfs_node_key_ptr_offset(src_nritems - push_items),
3316 push_items * sizeof(struct btrfs_key_ptr));
3318 btrfs_set_header_nritems(src, src_nritems - push_items);
3319 btrfs_set_header_nritems(dst, dst_nritems + push_items);
3321 btrfs_mark_buffer_dirty(src);
3322 btrfs_mark_buffer_dirty(dst);
3328 * helper function to insert a new root level in the tree.
3329 * A new node is allocated, and a single item is inserted to
3330 * point to the existing root
3332 * returns zero on success or < 0 on failure.
3334 static noinline int insert_new_root(struct btrfs_trans_handle *trans,
3335 struct btrfs_root *root,
3336 struct btrfs_path *path, int level)
3339 struct extent_buffer *lower;
3340 struct extent_buffer *c;
3341 struct extent_buffer *old;
3342 struct btrfs_disk_key lower_key;
3344 BUG_ON(path->nodes[level]);
3345 BUG_ON(path->nodes[level-1] != root->node);
3347 lower = path->nodes[level-1];
3349 btrfs_item_key(lower, &lower_key, 0);
3351 btrfs_node_key(lower, &lower_key, 0);
3353 c = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid,
3354 &lower_key, level, root->node->start, 0);
3358 root_add_used(root, root->nodesize);
3360 memset_extent_buffer(c, 0, 0, sizeof(struct btrfs_header));
3361 btrfs_set_header_nritems(c, 1);
3362 btrfs_set_header_level(c, level);
3363 btrfs_set_header_bytenr(c, c->start);
3364 btrfs_set_header_generation(c, trans->transid);
3365 btrfs_set_header_backref_rev(c, BTRFS_MIXED_BACKREF_REV);
3366 btrfs_set_header_owner(c, root->root_key.objectid);
3368 write_extent_buffer(c, root->fs_info->fsid, btrfs_header_fsid(),
3371 write_extent_buffer(c, root->fs_info->chunk_tree_uuid,
3372 btrfs_header_chunk_tree_uuid(c), BTRFS_UUID_SIZE);
3374 btrfs_set_node_key(c, &lower_key, 0);
3375 btrfs_set_node_blockptr(c, 0, lower->start);
3376 lower_gen = btrfs_header_generation(lower);
3377 WARN_ON(lower_gen != trans->transid);
3379 btrfs_set_node_ptr_generation(c, 0, lower_gen);
3381 btrfs_mark_buffer_dirty(c);
3384 tree_mod_log_set_root_pointer(root, c, 0);
3385 rcu_assign_pointer(root->node, c);
3387 /* the super has an extra ref to root->node */
3388 free_extent_buffer(old);
3390 add_root_to_dirty_list(root);
3391 extent_buffer_get(c);
3392 path->nodes[level] = c;
3393 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
3394 path->slots[level] = 0;
3399 * worker function to insert a single pointer in a node.
3400 * the node should have enough room for the pointer already
3402 * slot and level indicate where you want the key to go, and
3403 * blocknr is the block the key points to.
3405 static void insert_ptr(struct btrfs_trans_handle *trans,
3406 struct btrfs_root *root, struct btrfs_path *path,
3407 struct btrfs_disk_key *key, u64 bytenr,
3408 int slot, int level)
3410 struct extent_buffer *lower;
3414 BUG_ON(!path->nodes[level]);
3415 btrfs_assert_tree_locked(path->nodes[level]);
3416 lower = path->nodes[level];
3417 nritems = btrfs_header_nritems(lower);
3418 BUG_ON(slot > nritems);
3419 BUG_ON(nritems == BTRFS_NODEPTRS_PER_BLOCK(root));
3420 if (slot != nritems) {
3422 tree_mod_log_eb_move(root->fs_info, lower, slot + 1,
3423 slot, nritems - slot);
3424 memmove_extent_buffer(lower,
3425 btrfs_node_key_ptr_offset(slot + 1),
3426 btrfs_node_key_ptr_offset(slot),
3427 (nritems - slot) * sizeof(struct btrfs_key_ptr));
3430 ret = tree_mod_log_insert_key(root->fs_info, lower, slot,
3431 MOD_LOG_KEY_ADD, GFP_NOFS);
3434 btrfs_set_node_key(lower, key, slot);
3435 btrfs_set_node_blockptr(lower, slot, bytenr);
3436 WARN_ON(trans->transid == 0);
3437 btrfs_set_node_ptr_generation(lower, slot, trans->transid);
3438 btrfs_set_header_nritems(lower, nritems + 1);
3439 btrfs_mark_buffer_dirty(lower);
3443 * split the node at the specified level in path in two.
3444 * The path is corrected to point to the appropriate node after the split
3446 * Before splitting this tries to make some room in the node by pushing
3447 * left and right, if either one works, it returns right away.
3449 * returns 0 on success and < 0 on failure
3451 static noinline int split_node(struct btrfs_trans_handle *trans,
3452 struct btrfs_root *root,
3453 struct btrfs_path *path, int level)
3455 struct extent_buffer *c;
3456 struct extent_buffer *split;
3457 struct btrfs_disk_key disk_key;
3462 c = path->nodes[level];
3463 WARN_ON(btrfs_header_generation(c) != trans->transid);
3464 if (c == root->node) {
3466 * trying to split the root, lets make a new one
3468 * tree mod log: We don't log_removal old root in
3469 * insert_new_root, because that root buffer will be kept as a
3470 * normal node. We are going to log removal of half of the
3471 * elements below with tree_mod_log_eb_copy. We're holding a
3472 * tree lock on the buffer, which is why we cannot race with
3473 * other tree_mod_log users.
3475 ret = insert_new_root(trans, root, path, level + 1);
3479 ret = push_nodes_for_insert(trans, root, path, level);
3480 c = path->nodes[level];
3481 if (!ret && btrfs_header_nritems(c) <
3482 BTRFS_NODEPTRS_PER_BLOCK(root) - 3)
3488 c_nritems = btrfs_header_nritems(c);
3489 mid = (c_nritems + 1) / 2;
3490 btrfs_node_key(c, &disk_key, mid);
3492 split = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid,
3493 &disk_key, level, c->start, 0);
3495 return PTR_ERR(split);
3497 root_add_used(root, root->nodesize);
3499 memset_extent_buffer(split, 0, 0, sizeof(struct btrfs_header));
3500 btrfs_set_header_level(split, btrfs_header_level(c));
3501 btrfs_set_header_bytenr(split, split->start);
3502 btrfs_set_header_generation(split, trans->transid);
3503 btrfs_set_header_backref_rev(split, BTRFS_MIXED_BACKREF_REV);
3504 btrfs_set_header_owner(split, root->root_key.objectid);
3505 write_extent_buffer(split, root->fs_info->fsid,
3506 btrfs_header_fsid(), BTRFS_FSID_SIZE);
3507 write_extent_buffer(split, root->fs_info->chunk_tree_uuid,
3508 btrfs_header_chunk_tree_uuid(split),
3511 ret = tree_mod_log_eb_copy(root->fs_info, split, c, 0,
3512 mid, c_nritems - mid);
3514 btrfs_abort_transaction(trans, root, ret);
3517 copy_extent_buffer(split, c,
3518 btrfs_node_key_ptr_offset(0),
3519 btrfs_node_key_ptr_offset(mid),
3520 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
3521 btrfs_set_header_nritems(split, c_nritems - mid);
3522 btrfs_set_header_nritems(c, mid);
3525 btrfs_mark_buffer_dirty(c);
3526 btrfs_mark_buffer_dirty(split);
3528 insert_ptr(trans, root, path, &disk_key, split->start,
3529 path->slots[level + 1] + 1, level + 1);
3531 if (path->slots[level] >= mid) {
3532 path->slots[level] -= mid;
3533 btrfs_tree_unlock(c);
3534 free_extent_buffer(c);
3535 path->nodes[level] = split;
3536 path->slots[level + 1] += 1;
3538 btrfs_tree_unlock(split);
3539 free_extent_buffer(split);
3545 * how many bytes are required to store the items in a leaf. start
3546 * and nr indicate which items in the leaf to check. This totals up the
3547 * space used both by the item structs and the item data
3549 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
3551 struct btrfs_item *start_item;
3552 struct btrfs_item *end_item;
3553 struct btrfs_map_token token;
3555 int nritems = btrfs_header_nritems(l);
3556 int end = min(nritems, start + nr) - 1;
3560 btrfs_init_map_token(&token);
3561 start_item = btrfs_item_nr(start);
3562 end_item = btrfs_item_nr(end);
3563 data_len = btrfs_token_item_offset(l, start_item, &token) +
3564 btrfs_token_item_size(l, start_item, &token);
3565 data_len = data_len - btrfs_token_item_offset(l, end_item, &token);
3566 data_len += sizeof(struct btrfs_item) * nr;
3567 WARN_ON(data_len < 0);
3572 * The space between the end of the leaf items and
3573 * the start of the leaf data. IOW, how much room
3574 * the leaf has left for both items and data
3576 noinline int btrfs_leaf_free_space(struct btrfs_root *root,
3577 struct extent_buffer *leaf)
3579 int nritems = btrfs_header_nritems(leaf);
3581 ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
3583 btrfs_crit(root->fs_info,
3584 "leaf free space ret %d, leaf data size %lu, used %d nritems %d",
3585 ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
3586 leaf_space_used(leaf, 0, nritems), nritems);
3592 * min slot controls the lowest index we're willing to push to the
3593 * right. We'll push up to and including min_slot, but no lower
3595 static noinline int __push_leaf_right(struct btrfs_trans_handle *trans,
3596 struct btrfs_root *root,
3597 struct btrfs_path *path,
3598 int data_size, int empty,
3599 struct extent_buffer *right,
3600 int free_space, u32 left_nritems,
3603 struct extent_buffer *left = path->nodes[0];
3604 struct extent_buffer *upper = path->nodes[1];
3605 struct btrfs_map_token token;
3606 struct btrfs_disk_key disk_key;
3611 struct btrfs_item *item;
3617 btrfs_init_map_token(&token);
3622 nr = max_t(u32, 1, min_slot);
3624 if (path->slots[0] >= left_nritems)
3625 push_space += data_size;
3627 slot = path->slots[1];
3628 i = left_nritems - 1;
3630 item = btrfs_item_nr(i);
3632 if (!empty && push_items > 0) {
3633 if (path->slots[0] > i)
3635 if (path->slots[0] == i) {
3636 int space = btrfs_leaf_free_space(root, left);
3637 if (space + push_space * 2 > free_space)
3642 if (path->slots[0] == i)
3643 push_space += data_size;
3645 this_item_size = btrfs_item_size(left, item);
3646 if (this_item_size + sizeof(*item) + push_space > free_space)
3650 push_space += this_item_size + sizeof(*item);
3656 if (push_items == 0)
3659 WARN_ON(!empty && push_items == left_nritems);
3661 /* push left to right */
3662 right_nritems = btrfs_header_nritems(right);
3664 push_space = btrfs_item_end_nr(left, left_nritems - push_items);
3665 push_space -= leaf_data_end(root, left);
3667 /* make room in the right data area */
3668 data_end = leaf_data_end(root, right);
3669 memmove_extent_buffer(right,
3670 btrfs_leaf_data(right) + data_end - push_space,
3671 btrfs_leaf_data(right) + data_end,
3672 BTRFS_LEAF_DATA_SIZE(root) - data_end);
3674 /* copy from the left data area */
3675 copy_extent_buffer(right, left, btrfs_leaf_data(right) +
3676 BTRFS_LEAF_DATA_SIZE(root) - push_space,
3677 btrfs_leaf_data(left) + leaf_data_end(root, left),
3680 memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
3681 btrfs_item_nr_offset(0),
3682 right_nritems * sizeof(struct btrfs_item));
3684 /* copy the items from left to right */
3685 copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
3686 btrfs_item_nr_offset(left_nritems - push_items),
3687 push_items * sizeof(struct btrfs_item));
3689 /* update the item pointers */
3690 right_nritems += push_items;
3691 btrfs_set_header_nritems(right, right_nritems);
3692 push_space = BTRFS_LEAF_DATA_SIZE(root);
3693 for (i = 0; i < right_nritems; i++) {
3694 item = btrfs_item_nr(i);
3695 push_space -= btrfs_token_item_size(right, item, &token);
3696 btrfs_set_token_item_offset(right, item, push_space, &token);
3699 left_nritems -= push_items;
3700 btrfs_set_header_nritems(left, left_nritems);
3703 btrfs_mark_buffer_dirty(left);
3705 clean_tree_block(trans, root->fs_info, left);
3707 btrfs_mark_buffer_dirty(right);
3709 btrfs_item_key(right, &disk_key, 0);
3710 btrfs_set_node_key(upper, &disk_key, slot + 1);
3711 btrfs_mark_buffer_dirty(upper);
3713 /* then fixup the leaf pointer in the path */
3714 if (path->slots[0] >= left_nritems) {
3715 path->slots[0] -= left_nritems;
3716 if (btrfs_header_nritems(path->nodes[0]) == 0)
3717 clean_tree_block(trans, root->fs_info, path->nodes[0]);
3718 btrfs_tree_unlock(path->nodes[0]);
3719 free_extent_buffer(path->nodes[0]);
3720 path->nodes[0] = right;
3721 path->slots[1] += 1;
3723 btrfs_tree_unlock(right);
3724 free_extent_buffer(right);
3729 btrfs_tree_unlock(right);
3730 free_extent_buffer(right);
3735 * push some data in the path leaf to the right, trying to free up at
3736 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3738 * returns 1 if the push failed because the other node didn't have enough
3739 * room, 0 if everything worked out and < 0 if there were major errors.
3741 * this will push starting from min_slot to the end of the leaf. It won't
3742 * push any slot lower than min_slot
3744 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
3745 *root, struct btrfs_path *path,
3746 int min_data_size, int data_size,
3747 int empty, u32 min_slot)
3749 struct extent_buffer *left = path->nodes[0];
3750 struct extent_buffer *right;
3751 struct extent_buffer *upper;
3757 if (!path->nodes[1])
3760 slot = path->slots[1];
3761 upper = path->nodes[1];
3762 if (slot >= btrfs_header_nritems(upper) - 1)
3765 btrfs_assert_tree_locked(path->nodes[1]);
3767 right = read_node_slot(root, upper, slot + 1);
3771 btrfs_tree_lock(right);
3772 btrfs_set_lock_blocking(right);
3774 free_space = btrfs_leaf_free_space(root, right);
3775 if (free_space < data_size)
3778 /* cow and double check */
3779 ret = btrfs_cow_block(trans, root, right, upper,
3784 free_space = btrfs_leaf_free_space(root, right);
3785 if (free_space < data_size)
3788 left_nritems = btrfs_header_nritems(left);
3789 if (left_nritems == 0)
3792 if (path->slots[0] == left_nritems && !empty) {
3793 /* Key greater than all keys in the leaf, right neighbor has
3794 * enough room for it and we're not emptying our leaf to delete
3795 * it, therefore use right neighbor to insert the new item and
3796 * no need to touch/dirty our left leaft. */
3797 btrfs_tree_unlock(left);
3798 free_extent_buffer(left);
3799 path->nodes[0] = right;
3805 return __push_leaf_right(trans, root, path, min_data_size, empty,
3806 right, free_space, left_nritems, min_slot);
3808 btrfs_tree_unlock(right);
3809 free_extent_buffer(right);
3814 * push some data in the path leaf to the left, trying to free up at
3815 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3817 * max_slot can put a limit on how far into the leaf we'll push items. The
3818 * item at 'max_slot' won't be touched. Use (u32)-1 to make us do all the
3821 static noinline int __push_leaf_left(struct btrfs_trans_handle *trans,
3822 struct btrfs_root *root,
3823 struct btrfs_path *path, int data_size,
3824 int empty, struct extent_buffer *left,
3825 int free_space, u32 right_nritems,
3828 struct btrfs_disk_key disk_key;
3829 struct extent_buffer *right = path->nodes[0];
3833 struct btrfs_item *item;
3834 u32 old_left_nritems;
3838 u32 old_left_item_size;
3839 struct btrfs_map_token token;
3841 btrfs_init_map_token(&token);
3844 nr = min(right_nritems, max_slot);
3846 nr = min(right_nritems - 1, max_slot);
3848 for (i = 0; i < nr; i++) {
3849 item = btrfs_item_nr(i);
3851 if (!empty && push_items > 0) {
3852 if (path->slots[0] < i)
3854 if (path->slots[0] == i) {
3855 int space = btrfs_leaf_free_space(root, right);
3856 if (space + push_space * 2 > free_space)
3861 if (path->slots[0] == i)
3862 push_space += data_size;
3864 this_item_size = btrfs_item_size(right, item);
3865 if (this_item_size + sizeof(*item) + push_space > free_space)
3869 push_space += this_item_size + sizeof(*item);
3872 if (push_items == 0) {
3876 WARN_ON(!empty && push_items == btrfs_header_nritems(right));
3878 /* push data from right to left */
3879 copy_extent_buffer(left, right,
3880 btrfs_item_nr_offset(btrfs_header_nritems(left)),
3881 btrfs_item_nr_offset(0),
3882 push_items * sizeof(struct btrfs_item));
3884 push_space = BTRFS_LEAF_DATA_SIZE(root) -
3885 btrfs_item_offset_nr(right, push_items - 1);
3887 copy_extent_buffer(left, right, btrfs_leaf_data(left) +
3888 leaf_data_end(root, left) - push_space,
3889 btrfs_leaf_data(right) +
3890 btrfs_item_offset_nr(right, push_items - 1),
3892 old_left_nritems = btrfs_header_nritems(left);
3893 BUG_ON(old_left_nritems <= 0);
3895 old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
3896 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
3899 item = btrfs_item_nr(i);
3901 ioff = btrfs_token_item_offset(left, item, &token);
3902 btrfs_set_token_item_offset(left, item,
3903 ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size),
3906 btrfs_set_header_nritems(left, old_left_nritems + push_items);
3908 /* fixup right node */
3909 if (push_items > right_nritems)
3910 WARN(1, KERN_CRIT "push items %d nr %u\n", push_items,
3913 if (push_items < right_nritems) {
3914 push_space = btrfs_item_offset_nr(right, push_items - 1) -
3915 leaf_data_end(root, right);
3916 memmove_extent_buffer(right, btrfs_leaf_data(right) +
3917 BTRFS_LEAF_DATA_SIZE(root) - push_space,
3918 btrfs_leaf_data(right) +
3919 leaf_data_end(root, right), push_space);
3921 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
3922 btrfs_item_nr_offset(push_items),
3923 (btrfs_header_nritems(right) - push_items) *
3924 sizeof(struct btrfs_item));
3926 right_nritems -= push_items;
3927 btrfs_set_header_nritems(right, right_nritems);
3928 push_space = BTRFS_LEAF_DATA_SIZE(root);
3929 for (i = 0; i < right_nritems; i++) {
3930 item = btrfs_item_nr(i);
3932 push_space = push_space - btrfs_token_item_size(right,
3934 btrfs_set_token_item_offset(right, item, push_space, &token);
3937 btrfs_mark_buffer_dirty(left);
3939 btrfs_mark_buffer_dirty(right);
3941 clean_tree_block(trans, root->fs_info, right);
3943 btrfs_item_key(right, &disk_key, 0);
3944 fixup_low_keys(root->fs_info, path, &disk_key, 1);
3946 /* then fixup the leaf pointer in the path */
3947 if (path->slots[0] < push_items) {
3948 path->slots[0] += old_left_nritems;
3949 btrfs_tree_unlock(path->nodes[0]);
3950 free_extent_buffer(path->nodes[0]);
3951 path->nodes[0] = left;
3952 path->slots[1] -= 1;
3954 btrfs_tree_unlock(left);
3955 free_extent_buffer(left);
3956 path->slots[0] -= push_items;
3958 BUG_ON(path->slots[0] < 0);
3961 btrfs_tree_unlock(left);
3962 free_extent_buffer(left);
3967 * push some data in the path leaf to the left, trying to free up at
3968 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3970 * max_slot can put a limit on how far into the leaf we'll push items. The
3971 * item at 'max_slot' won't be touched. Use (u32)-1 to make us push all the
3974 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
3975 *root, struct btrfs_path *path, int min_data_size,
3976 int data_size, int empty, u32 max_slot)
3978 struct extent_buffer *right = path->nodes[0];
3979 struct extent_buffer *left;
3985 slot = path->slots[1];
3988 if (!path->nodes[1])
3991 right_nritems = btrfs_header_nritems(right);
3992 if (right_nritems == 0)
3995 btrfs_assert_tree_locked(path->nodes[1]);
3997 left = read_node_slot(root, path->nodes[1], slot - 1);
4001 btrfs_tree_lock(left);
4002 btrfs_set_lock_blocking(left);
4004 free_space = btrfs_leaf_free_space(root, left);
4005 if (free_space < data_size) {
4010 /* cow and double check */
4011 ret = btrfs_cow_block(trans, root, left,
4012 path->nodes[1], slot - 1, &left);
4014 /* we hit -ENOSPC, but it isn't fatal here */
4020 free_space = btrfs_leaf_free_space(root, left);
4021 if (free_space < data_size) {
4026 return __push_leaf_left(trans, root, path, min_data_size,
4027 empty, left, free_space, right_nritems,
4030 btrfs_tree_unlock(left);
4031 free_extent_buffer(left);
4036 * split the path's leaf in two, making sure there is at least data_size
4037 * available for the resulting leaf level of the path.
4039 static noinline void copy_for_split(struct btrfs_trans_handle *trans,
4040 struct btrfs_root *root,
4041 struct btrfs_path *path,
4042 struct extent_buffer *l,
4043 struct extent_buffer *right,
4044 int slot, int mid, int nritems)
4049 struct btrfs_disk_key disk_key;
4050 struct btrfs_map_token token;
4052 btrfs_init_map_token(&token);
4054 nritems = nritems - mid;
4055 btrfs_set_header_nritems(right, nritems);
4056 data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
4058 copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
4059 btrfs_item_nr_offset(mid),
4060 nritems * sizeof(struct btrfs_item));
4062 copy_extent_buffer(right, l,
4063 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
4064 data_copy_size, btrfs_leaf_data(l) +
4065 leaf_data_end(root, l), data_copy_size);
4067 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
4068 btrfs_item_end_nr(l, mid);
4070 for (i = 0; i < nritems; i++) {
4071 struct btrfs_item *item = btrfs_item_nr(i);
4074 ioff = btrfs_token_item_offset(right, item, &token);
4075 btrfs_set_token_item_offset(right, item,
4076 ioff + rt_data_off, &token);
4079 btrfs_set_header_nritems(l, mid);
4080 btrfs_item_key(right, &disk_key, 0);
4081 insert_ptr(trans, root, path, &disk_key, right->start,
4082 path->slots[1] + 1, 1);
4084 btrfs_mark_buffer_dirty(right);
4085 btrfs_mark_buffer_dirty(l);
4086 BUG_ON(path->slots[0] != slot);
4089 btrfs_tree_unlock(path->nodes[0]);
4090 free_extent_buffer(path->nodes[0]);
4091 path->nodes[0] = right;
4092 path->slots[0] -= mid;
4093 path->slots[1] += 1;
4095 btrfs_tree_unlock(right);
4096 free_extent_buffer(right);
4099 BUG_ON(path->slots[0] < 0);
4103 * double splits happen when we need to insert a big item in the middle
4104 * of a leaf. A double split can leave us with 3 mostly empty leaves:
4105 * leaf: [ slots 0 - N] [ our target ] [ N + 1 - total in leaf ]
4108 * We avoid this by trying to push the items on either side of our target
4109 * into the adjacent leaves. If all goes well we can avoid the double split
4112 static noinline int push_for_double_split(struct btrfs_trans_handle *trans,
4113 struct btrfs_root *root,
4114 struct btrfs_path *path,
4121 int space_needed = data_size;
4123 slot = path->slots[0];
4124 if (slot < btrfs_header_nritems(path->nodes[0]))
4125 space_needed -= btrfs_leaf_free_space(root, path->nodes[0]);
4128 * try to push all the items after our slot into the
4131 ret = push_leaf_right(trans, root, path, 1, space_needed, 0, slot);
4138 nritems = btrfs_header_nritems(path->nodes[0]);
4140 * our goal is to get our slot at the start or end of a leaf. If
4141 * we've done so we're done
4143 if (path->slots[0] == 0 || path->slots[0] == nritems)
4146 if (btrfs_leaf_free_space(root, path->nodes[0]) >= data_size)
4149 /* try to push all the items before our slot into the next leaf */
4150 slot = path->slots[0];
4151 ret = push_leaf_left(trans, root, path, 1, space_needed, 0, slot);
4164 * split the path's leaf in two, making sure there is at least data_size
4165 * available for the resulting leaf level of the path.
4167 * returns 0 if all went well and < 0 on failure.
4169 static noinline int split_leaf(struct btrfs_trans_handle *trans,
4170 struct btrfs_root *root,
4171 struct btrfs_key *ins_key,
4172 struct btrfs_path *path, int data_size,
4175 struct btrfs_disk_key disk_key;
4176 struct extent_buffer *l;
4180 struct extent_buffer *right;
4181 struct btrfs_fs_info *fs_info = root->fs_info;
4185 int num_doubles = 0;
4186 int tried_avoid_double = 0;
4189 slot = path->slots[0];
4190 if (extend && data_size + btrfs_item_size_nr(l, slot) +
4191 sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(root))
4194 /* first try to make some room by pushing left and right */
4195 if (data_size && path->nodes[1]) {
4196 int space_needed = data_size;
4198 if (slot < btrfs_header_nritems(l))
4199 space_needed -= btrfs_leaf_free_space(root, l);
4201 wret = push_leaf_right(trans, root, path, space_needed,
4202 space_needed, 0, 0);
4206 wret = push_leaf_left(trans, root, path, space_needed,
4207 space_needed, 0, (u32)-1);
4213 /* did the pushes work? */
4214 if (btrfs_leaf_free_space(root, l) >= data_size)
4218 if (!path->nodes[1]) {
4219 ret = insert_new_root(trans, root, path, 1);
4226 slot = path->slots[0];
4227 nritems = btrfs_header_nritems(l);
4228 mid = (nritems + 1) / 2;
4232 leaf_space_used(l, mid, nritems - mid) + data_size >
4233 BTRFS_LEAF_DATA_SIZE(root)) {
4234 if (slot >= nritems) {
4238 if (mid != nritems &&
4239 leaf_space_used(l, mid, nritems - mid) +
4240 data_size > BTRFS_LEAF_DATA_SIZE(root)) {
4241 if (data_size && !tried_avoid_double)
4242 goto push_for_double;
4248 if (leaf_space_used(l, 0, mid) + data_size >
4249 BTRFS_LEAF_DATA_SIZE(root)) {
4250 if (!extend && data_size && slot == 0) {
4252 } else if ((extend || !data_size) && slot == 0) {
4256 if (mid != nritems &&
4257 leaf_space_used(l, mid, nritems - mid) +
4258 data_size > BTRFS_LEAF_DATA_SIZE(root)) {
4259 if (data_size && !tried_avoid_double)
4260 goto push_for_double;
4268 btrfs_cpu_key_to_disk(&disk_key, ins_key);
4270 btrfs_item_key(l, &disk_key, mid);
4272 right = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid,
4273 &disk_key, 0, l->start, 0);
4275 return PTR_ERR(right);
4277 root_add_used(root, root->nodesize);
4279 memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
4280 btrfs_set_header_bytenr(right, right->start);
4281 btrfs_set_header_generation(right, trans->transid);
4282 btrfs_set_header_backref_rev(right, BTRFS_MIXED_BACKREF_REV);
4283 btrfs_set_header_owner(right, root->root_key.objectid);
4284 btrfs_set_header_level(right, 0);
4285 write_extent_buffer(right, fs_info->fsid,
4286 btrfs_header_fsid(), BTRFS_FSID_SIZE);
4288 write_extent_buffer(right, fs_info->chunk_tree_uuid,
4289 btrfs_header_chunk_tree_uuid(right),
4294 btrfs_set_header_nritems(right, 0);
4295 insert_ptr(trans, root, path, &disk_key, right->start,
4296 path->slots[1] + 1, 1);
4297 btrfs_tree_unlock(path->nodes[0]);
4298 free_extent_buffer(path->nodes[0]);
4299 path->nodes[0] = right;
4301 path->slots[1] += 1;
4303 btrfs_set_header_nritems(right, 0);
4304 insert_ptr(trans, root, path, &disk_key, right->start,
4306 btrfs_tree_unlock(path->nodes[0]);
4307 free_extent_buffer(path->nodes[0]);
4308 path->nodes[0] = right;
4310 if (path->slots[1] == 0)
4311 fixup_low_keys(fs_info, path, &disk_key, 1);
4313 btrfs_mark_buffer_dirty(right);
4317 copy_for_split(trans, root, path, l, right, slot, mid, nritems);
4320 BUG_ON(num_doubles != 0);
4328 push_for_double_split(trans, root, path, data_size);
4329 tried_avoid_double = 1;
4330 if (btrfs_leaf_free_space(root, path->nodes[0]) >= data_size)
4335 static noinline int setup_leaf_for_split(struct btrfs_trans_handle *trans,
4336 struct btrfs_root *root,
4337 struct btrfs_path *path, int ins_len)
4339 struct btrfs_key key;
4340 struct extent_buffer *leaf;
4341 struct btrfs_file_extent_item *fi;
4346 leaf = path->nodes[0];
4347 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4349 BUG_ON(key.type != BTRFS_EXTENT_DATA_KEY &&
4350 key.type != BTRFS_EXTENT_CSUM_KEY);
4352 if (btrfs_leaf_free_space(root, leaf) >= ins_len)
4355 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
4356 if (key.type == BTRFS_EXTENT_DATA_KEY) {
4357 fi = btrfs_item_ptr(leaf, path->slots[0],
4358 struct btrfs_file_extent_item);
4359 extent_len = btrfs_file_extent_num_bytes(leaf, fi);
4361 btrfs_release_path(path);
4363 path->keep_locks = 1;
4364 path->search_for_split = 1;
4365 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
4366 path->search_for_split = 0;
4373 leaf = path->nodes[0];
4374 /* if our item isn't there, return now */
4375 if (item_size != btrfs_item_size_nr(leaf, path->slots[0]))
4378 /* the leaf has changed, it now has room. return now */
4379 if (btrfs_leaf_free_space(root, path->nodes[0]) >= ins_len)
4382 if (key.type == BTRFS_EXTENT_DATA_KEY) {
4383 fi = btrfs_item_ptr(leaf, path->slots[0],
4384 struct btrfs_file_extent_item);
4385 if (extent_len != btrfs_file_extent_num_bytes(leaf, fi))
4389 btrfs_set_path_blocking(path);
4390 ret = split_leaf(trans, root, &key, path, ins_len, 1);
4394 path->keep_locks = 0;
4395 btrfs_unlock_up_safe(path, 1);
4398 path->keep_locks = 0;
4402 static noinline int split_item(struct btrfs_trans_handle *trans,
4403 struct btrfs_root *root,
4404 struct btrfs_path *path,
4405 struct btrfs_key *new_key,
4406 unsigned long split_offset)
4408 struct extent_buffer *leaf;
4409 struct btrfs_item *item;
4410 struct btrfs_item *new_item;
4416 struct btrfs_disk_key disk_key;
4418 leaf = path->nodes[0];
4419 BUG_ON(btrfs_leaf_free_space(root, leaf) < sizeof(struct btrfs_item));
4421 btrfs_set_path_blocking(path);
4423 item = btrfs_item_nr(path->slots[0]);
4424 orig_offset = btrfs_item_offset(leaf, item);
4425 item_size = btrfs_item_size(leaf, item);
4427 buf = kmalloc(item_size, GFP_NOFS);
4431 read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf,
4432 path->slots[0]), item_size);
4434 slot = path->slots[0] + 1;
4435 nritems = btrfs_header_nritems(leaf);
4436 if (slot != nritems) {
4437 /* shift the items */
4438 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1),
4439 btrfs_item_nr_offset(slot),
4440 (nritems - slot) * sizeof(struct btrfs_item));
4443 btrfs_cpu_key_to_disk(&disk_key, new_key);
4444 btrfs_set_item_key(leaf, &disk_key, slot);
4446 new_item = btrfs_item_nr(slot);
4448 btrfs_set_item_offset(leaf, new_item, orig_offset);
4449 btrfs_set_item_size(leaf, new_item, item_size - split_offset);
4451 btrfs_set_item_offset(leaf, item,
4452 orig_offset + item_size - split_offset);
4453 btrfs_set_item_size(leaf, item, split_offset);
4455 btrfs_set_header_nritems(leaf, nritems + 1);
4457 /* write the data for the start of the original item */
4458 write_extent_buffer(leaf, buf,
4459 btrfs_item_ptr_offset(leaf, path->slots[0]),
4462 /* write the data for the new item */
4463 write_extent_buffer(leaf, buf + split_offset,
4464 btrfs_item_ptr_offset(leaf, slot),
4465 item_size - split_offset);
4466 btrfs_mark_buffer_dirty(leaf);
4468 BUG_ON(btrfs_leaf_free_space(root, leaf) < 0);
4474 * This function splits a single item into two items,
4475 * giving 'new_key' to the new item and splitting the
4476 * old one at split_offset (from the start of the item).
4478 * The path may be released by this operation. After
4479 * the split, the path is pointing to the old item. The
4480 * new item is going to be in the same node as the old one.
4482 * Note, the item being split must be smaller enough to live alone on
4483 * a tree block with room for one extra struct btrfs_item
4485 * This allows us to split the item in place, keeping a lock on the
4486 * leaf the entire time.
4488 int btrfs_split_item(struct btrfs_trans_handle *trans,
4489 struct btrfs_root *root,
4490 struct btrfs_path *path,
4491 struct btrfs_key *new_key,
4492 unsigned long split_offset)
4495 ret = setup_leaf_for_split(trans, root, path,
4496 sizeof(struct btrfs_item));
4500 ret = split_item(trans, root, path, new_key, split_offset);
4505 * This function duplicate a item, giving 'new_key' to the new item.
4506 * It guarantees both items live in the same tree leaf and the new item
4507 * is contiguous with the original item.
4509 * This allows us to split file extent in place, keeping a lock on the
4510 * leaf the entire time.
4512 int btrfs_duplicate_item(struct btrfs_trans_handle *trans,
4513 struct btrfs_root *root,
4514 struct btrfs_path *path,
4515 struct btrfs_key *new_key)
4517 struct extent_buffer *leaf;
4521 leaf = path->nodes[0];
4522 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
4523 ret = setup_leaf_for_split(trans, root, path,
4524 item_size + sizeof(struct btrfs_item));
4529 setup_items_for_insert(root, path, new_key, &item_size,
4530 item_size, item_size +
4531 sizeof(struct btrfs_item), 1);
4532 leaf = path->nodes[0];
4533 memcpy_extent_buffer(leaf,
4534 btrfs_item_ptr_offset(leaf, path->slots[0]),
4535 btrfs_item_ptr_offset(leaf, path->slots[0] - 1),
4541 * make the item pointed to by the path smaller. new_size indicates
4542 * how small to make it, and from_end tells us if we just chop bytes
4543 * off the end of the item or if we shift the item to chop bytes off
4546 void btrfs_truncate_item(struct btrfs_root *root, struct btrfs_path *path,
4547 u32 new_size, int from_end)
4550 struct extent_buffer *leaf;
4551 struct btrfs_item *item;
4553 unsigned int data_end;
4554 unsigned int old_data_start;
4555 unsigned int old_size;
4556 unsigned int size_diff;
4558 struct btrfs_map_token token;
4560 btrfs_init_map_token(&token);
4562 leaf = path->nodes[0];
4563 slot = path->slots[0];
4565 old_size = btrfs_item_size_nr(leaf, slot);
4566 if (old_size == new_size)
4569 nritems = btrfs_header_nritems(leaf);
4570 data_end = leaf_data_end(root, leaf);
4572 old_data_start = btrfs_item_offset_nr(leaf, slot);
4574 size_diff = old_size - new_size;
4577 BUG_ON(slot >= nritems);
4580 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4582 /* first correct the data pointers */
4583 for (i = slot; i < nritems; i++) {
4585 item = btrfs_item_nr(i);
4587 ioff = btrfs_token_item_offset(leaf, item, &token);
4588 btrfs_set_token_item_offset(leaf, item,
4589 ioff + size_diff, &token);
4592 /* shift the data */
4594 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
4595 data_end + size_diff, btrfs_leaf_data(leaf) +
4596 data_end, old_data_start + new_size - data_end);
4598 struct btrfs_disk_key disk_key;
4601 btrfs_item_key(leaf, &disk_key, slot);
4603 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
4605 struct btrfs_file_extent_item *fi;
4607 fi = btrfs_item_ptr(leaf, slot,
4608 struct btrfs_file_extent_item);
4609 fi = (struct btrfs_file_extent_item *)(
4610 (unsigned long)fi - size_diff);
4612 if (btrfs_file_extent_type(leaf, fi) ==
4613 BTRFS_FILE_EXTENT_INLINE) {
4614 ptr = btrfs_item_ptr_offset(leaf, slot);
4615 memmove_extent_buffer(leaf, ptr,
4617 BTRFS_FILE_EXTENT_INLINE_DATA_START);
4621 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
4622 data_end + size_diff, btrfs_leaf_data(leaf) +
4623 data_end, old_data_start - data_end);
4625 offset = btrfs_disk_key_offset(&disk_key);
4626 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
4627 btrfs_set_item_key(leaf, &disk_key, slot);
4629 fixup_low_keys(root->fs_info, path, &disk_key, 1);
4632 item = btrfs_item_nr(slot);
4633 btrfs_set_item_size(leaf, item, new_size);
4634 btrfs_mark_buffer_dirty(leaf);
4636 if (btrfs_leaf_free_space(root, leaf) < 0) {
4637 btrfs_print_leaf(root, leaf);
4643 * make the item pointed to by the path bigger, data_size is the added size.
4645 void btrfs_extend_item(struct btrfs_root *root, struct btrfs_path *path,
4649 struct extent_buffer *leaf;
4650 struct btrfs_item *item;
4652 unsigned int data_end;
4653 unsigned int old_data;
4654 unsigned int old_size;
4656 struct btrfs_map_token token;
4658 btrfs_init_map_token(&token);
4660 leaf = path->nodes[0];
4662 nritems = btrfs_header_nritems(leaf);
4663 data_end = leaf_data_end(root, leaf);
4665 if (btrfs_leaf_free_space(root, leaf) < data_size) {
4666 btrfs_print_leaf(root, leaf);
4669 slot = path->slots[0];
4670 old_data = btrfs_item_end_nr(leaf, slot);
4673 if (slot >= nritems) {
4674 btrfs_print_leaf(root, leaf);
4675 btrfs_crit(root->fs_info, "slot %d too large, nritems %d",
4681 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4683 /* first correct the data pointers */
4684 for (i = slot; i < nritems; i++) {
4686 item = btrfs_item_nr(i);
4688 ioff = btrfs_token_item_offset(leaf, item, &token);
4689 btrfs_set_token_item_offset(leaf, item,
4690 ioff - data_size, &token);
4693 /* shift the data */
4694 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
4695 data_end - data_size, btrfs_leaf_data(leaf) +
4696 data_end, old_data - data_end);
4698 data_end = old_data;
4699 old_size = btrfs_item_size_nr(leaf, slot);
4700 item = btrfs_item_nr(slot);
4701 btrfs_set_item_size(leaf, item, old_size + data_size);
4702 btrfs_mark_buffer_dirty(leaf);
4704 if (btrfs_leaf_free_space(root, leaf) < 0) {
4705 btrfs_print_leaf(root, leaf);
4711 * this is a helper for btrfs_insert_empty_items, the main goal here is
4712 * to save stack depth by doing the bulk of the work in a function
4713 * that doesn't call btrfs_search_slot
4715 void setup_items_for_insert(struct btrfs_root *root, struct btrfs_path *path,
4716 struct btrfs_key *cpu_key, u32 *data_size,
4717 u32 total_data, u32 total_size, int nr)
4719 struct btrfs_item *item;
4722 unsigned int data_end;
4723 struct btrfs_disk_key disk_key;
4724 struct extent_buffer *leaf;
4726 struct btrfs_map_token token;
4728 if (path->slots[0] == 0) {
4729 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
4730 fixup_low_keys(root->fs_info, path, &disk_key, 1);
4732 btrfs_unlock_up_safe(path, 1);
4734 btrfs_init_map_token(&token);
4736 leaf = path->nodes[0];
4737 slot = path->slots[0];
4739 nritems = btrfs_header_nritems(leaf);
4740 data_end = leaf_data_end(root, leaf);
4742 if (btrfs_leaf_free_space(root, leaf) < total_size) {
4743 btrfs_print_leaf(root, leaf);
4744 btrfs_crit(root->fs_info, "not enough freespace need %u have %d",
4745 total_size, btrfs_leaf_free_space(root, leaf));
4749 if (slot != nritems) {
4750 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
4752 if (old_data < data_end) {
4753 btrfs_print_leaf(root, leaf);
4754 btrfs_crit(root->fs_info, "slot %d old_data %d data_end %d",
4755 slot, old_data, data_end);
4759 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4761 /* first correct the data pointers */
4762 for (i = slot; i < nritems; i++) {
4765 item = btrfs_item_nr( i);
4766 ioff = btrfs_token_item_offset(leaf, item, &token);
4767 btrfs_set_token_item_offset(leaf, item,
4768 ioff - total_data, &token);
4770 /* shift the items */
4771 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
4772 btrfs_item_nr_offset(slot),
4773 (nritems - slot) * sizeof(struct btrfs_item));
4775 /* shift the data */
4776 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
4777 data_end - total_data, btrfs_leaf_data(leaf) +
4778 data_end, old_data - data_end);
4779 data_end = old_data;
4782 /* setup the item for the new data */
4783 for (i = 0; i < nr; i++) {
4784 btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
4785 btrfs_set_item_key(leaf, &disk_key, slot + i);
4786 item = btrfs_item_nr(slot + i);
4787 btrfs_set_token_item_offset(leaf, item,
4788 data_end - data_size[i], &token);
4789 data_end -= data_size[i];
4790 btrfs_set_token_item_size(leaf, item, data_size[i], &token);
4793 btrfs_set_header_nritems(leaf, nritems + nr);
4794 btrfs_mark_buffer_dirty(leaf);
4796 if (btrfs_leaf_free_space(root, leaf) < 0) {
4797 btrfs_print_leaf(root, leaf);
4803 * Given a key and some data, insert items into the tree.
4804 * This does all the path init required, making room in the tree if needed.
4806 int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
4807 struct btrfs_root *root,
4808 struct btrfs_path *path,
4809 struct btrfs_key *cpu_key, u32 *data_size,
4818 for (i = 0; i < nr; i++)
4819 total_data += data_size[i];
4821 total_size = total_data + (nr * sizeof(struct btrfs_item));
4822 ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
4828 slot = path->slots[0];
4831 setup_items_for_insert(root, path, cpu_key, data_size,
4832 total_data, total_size, nr);
4837 * Given a key and some data, insert an item into the tree.
4838 * This does all the path init required, making room in the tree if needed.
4840 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
4841 *root, struct btrfs_key *cpu_key, void *data, u32
4845 struct btrfs_path *path;
4846 struct extent_buffer *leaf;
4849 path = btrfs_alloc_path();
4852 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
4854 leaf = path->nodes[0];
4855 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
4856 write_extent_buffer(leaf, data, ptr, data_size);
4857 btrfs_mark_buffer_dirty(leaf);
4859 btrfs_free_path(path);
4864 * delete the pointer from a given node.
4866 * the tree should have been previously balanced so the deletion does not
4869 static void del_ptr(struct btrfs_root *root, struct btrfs_path *path,
4870 int level, int slot)
4872 struct extent_buffer *parent = path->nodes[level];
4876 nritems = btrfs_header_nritems(parent);
4877 if (slot != nritems - 1) {
4879 tree_mod_log_eb_move(root->fs_info, parent, slot,
4880 slot + 1, nritems - slot - 1);
4881 memmove_extent_buffer(parent,
4882 btrfs_node_key_ptr_offset(slot),
4883 btrfs_node_key_ptr_offset(slot + 1),
4884 sizeof(struct btrfs_key_ptr) *
4885 (nritems - slot - 1));
4887 ret = tree_mod_log_insert_key(root->fs_info, parent, slot,
4888 MOD_LOG_KEY_REMOVE, GFP_NOFS);
4893 btrfs_set_header_nritems(parent, nritems);
4894 if (nritems == 0 && parent == root->node) {
4895 BUG_ON(btrfs_header_level(root->node) != 1);
4896 /* just turn the root into a leaf and break */
4897 btrfs_set_header_level(root->node, 0);
4898 } else if (slot == 0) {
4899 struct btrfs_disk_key disk_key;
4901 btrfs_node_key(parent, &disk_key, 0);
4902 fixup_low_keys(root->fs_info, path, &disk_key, level + 1);
4904 btrfs_mark_buffer_dirty(parent);
4908 * a helper function to delete the leaf pointed to by path->slots[1] and
4911 * This deletes the pointer in path->nodes[1] and frees the leaf
4912 * block extent. zero is returned if it all worked out, < 0 otherwise.
4914 * The path must have already been setup for deleting the leaf, including
4915 * all the proper balancing. path->nodes[1] must be locked.
4917 static noinline void btrfs_del_leaf(struct btrfs_trans_handle *trans,
4918 struct btrfs_root *root,
4919 struct btrfs_path *path,
4920 struct extent_buffer *leaf)
4922 WARN_ON(btrfs_header_generation(leaf) != trans->transid);
4923 del_ptr(root, path, 1, path->slots[1]);
4926 * btrfs_free_extent is expensive, we want to make sure we
4927 * aren't holding any locks when we call it
4929 btrfs_unlock_up_safe(path, 0);
4931 root_sub_used(root, leaf->len);
4933 extent_buffer_get(leaf);
4934 btrfs_free_tree_block(trans, root, leaf, 0, 1);
4935 free_extent_buffer_stale(leaf);
4938 * delete the item at the leaf level in path. If that empties
4939 * the leaf, remove it from the tree
4941 int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
4942 struct btrfs_path *path, int slot, int nr)
4944 struct extent_buffer *leaf;
4945 struct btrfs_item *item;
4952 struct btrfs_map_token token;
4954 btrfs_init_map_token(&token);
4956 leaf = path->nodes[0];
4957 last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
4959 for (i = 0; i < nr; i++)
4960 dsize += btrfs_item_size_nr(leaf, slot + i);
4962 nritems = btrfs_header_nritems(leaf);
4964 if (slot + nr != nritems) {
4965 int data_end = leaf_data_end(root, leaf);
4967 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
4969 btrfs_leaf_data(leaf) + data_end,
4970 last_off - data_end);
4972 for (i = slot + nr; i < nritems; i++) {
4975 item = btrfs_item_nr(i);
4976 ioff = btrfs_token_item_offset(leaf, item, &token);
4977 btrfs_set_token_item_offset(leaf, item,
4978 ioff + dsize, &token);
4981 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
4982 btrfs_item_nr_offset(slot + nr),
4983 sizeof(struct btrfs_item) *
4984 (nritems - slot - nr));
4986 btrfs_set_header_nritems(leaf, nritems - nr);
4989 /* delete the leaf if we've emptied it */
4991 if (leaf == root->node) {
4992 btrfs_set_header_level(leaf, 0);
4994 btrfs_set_path_blocking(path);
4995 clean_tree_block(trans, root->fs_info, leaf);
4996 btrfs_del_leaf(trans, root, path, leaf);
4999 int used = leaf_space_used(leaf, 0, nritems);
5001 struct btrfs_disk_key disk_key;
5003 btrfs_item_key(leaf, &disk_key, 0);
5004 fixup_low_keys(root->fs_info, path, &disk_key, 1);
5007 /* delete the leaf if it is mostly empty */
5008 if (used < BTRFS_LEAF_DATA_SIZE(root) / 3) {
5009 /* push_leaf_left fixes the path.
5010 * make sure the path still points to our leaf
5011 * for possible call to del_ptr below
5013 slot = path->slots[1];
5014 extent_buffer_get(leaf);
5016 btrfs_set_path_blocking(path);
5017 wret = push_leaf_left(trans, root, path, 1, 1,
5019 if (wret < 0 && wret != -ENOSPC)
5022 if (path->nodes[0] == leaf &&
5023 btrfs_header_nritems(leaf)) {
5024 wret = push_leaf_right(trans, root, path, 1,
5026 if (wret < 0 && wret != -ENOSPC)
5030 if (btrfs_header_nritems(leaf) == 0) {
5031 path->slots[1] = slot;
5032 btrfs_del_leaf(trans, root, path, leaf);
5033 free_extent_buffer(leaf);
5036 /* if we're still in the path, make sure
5037 * we're dirty. Otherwise, one of the
5038 * push_leaf functions must have already
5039 * dirtied this buffer
5041 if (path->nodes[0] == leaf)
5042 btrfs_mark_buffer_dirty(leaf);
5043 free_extent_buffer(leaf);
5046 btrfs_mark_buffer_dirty(leaf);
5053 * search the tree again to find a leaf with lesser keys
5054 * returns 0 if it found something or 1 if there are no lesser leaves.
5055 * returns < 0 on io errors.
5057 * This may release the path, and so you may lose any locks held at the
5060 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
5062 struct btrfs_key key;
5063 struct btrfs_disk_key found_key;
5066 btrfs_item_key_to_cpu(path->nodes[0], &key, 0);
5068 if (key.offset > 0) {
5070 } else if (key.type > 0) {
5072 key.offset = (u64)-1;
5073 } else if (key.objectid > 0) {
5076 key.offset = (u64)-1;
5081 btrfs_release_path(path);
5082 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5085 btrfs_item_key(path->nodes[0], &found_key, 0);
5086 ret = comp_keys(&found_key, &key);
5088 * We might have had an item with the previous key in the tree right
5089 * before we released our path. And after we released our path, that
5090 * item might have been pushed to the first slot (0) of the leaf we
5091 * were holding due to a tree balance. Alternatively, an item with the
5092 * previous key can exist as the only element of a leaf (big fat item).
5093 * Therefore account for these 2 cases, so that our callers (like
5094 * btrfs_previous_item) don't miss an existing item with a key matching
5095 * the previous key we computed above.
5103 * A helper function to walk down the tree starting at min_key, and looking
5104 * for nodes or leaves that are have a minimum transaction id.
5105 * This is used by the btree defrag code, and tree logging
5107 * This does not cow, but it does stuff the starting key it finds back
5108 * into min_key, so you can call btrfs_search_slot with cow=1 on the
5109 * key and get a writable path.
5111 * This does lock as it descends, and path->keep_locks should be set
5112 * to 1 by the caller.
5114 * This honors path->lowest_level to prevent descent past a given level
5117 * min_trans indicates the oldest transaction that you are interested
5118 * in walking through. Any nodes or leaves older than min_trans are
5119 * skipped over (without reading them).
5121 * returns zero if something useful was found, < 0 on error and 1 if there
5122 * was nothing in the tree that matched the search criteria.
5124 int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
5125 struct btrfs_path *path,
5128 struct extent_buffer *cur;
5129 struct btrfs_key found_key;
5135 int keep_locks = path->keep_locks;
5137 path->keep_locks = 1;
5139 cur = btrfs_read_lock_root_node(root);
5140 level = btrfs_header_level(cur);
5141 WARN_ON(path->nodes[level]);
5142 path->nodes[level] = cur;
5143 path->locks[level] = BTRFS_READ_LOCK;
5145 if (btrfs_header_generation(cur) < min_trans) {
5150 nritems = btrfs_header_nritems(cur);
5151 level = btrfs_header_level(cur);
5152 sret = bin_search(cur, min_key, level, &slot);
5154 /* at the lowest level, we're done, setup the path and exit */
5155 if (level == path->lowest_level) {
5156 if (slot >= nritems)
5159 path->slots[level] = slot;
5160 btrfs_item_key_to_cpu(cur, &found_key, slot);
5163 if (sret && slot > 0)
5166 * check this node pointer against the min_trans parameters.
5167 * If it is too old, old, skip to the next one.
5169 while (slot < nritems) {
5172 gen = btrfs_node_ptr_generation(cur, slot);
5173 if (gen < min_trans) {
5181 * we didn't find a candidate key in this node, walk forward
5182 * and find another one
5184 if (slot >= nritems) {
5185 path->slots[level] = slot;
5186 btrfs_set_path_blocking(path);
5187 sret = btrfs_find_next_key(root, path, min_key, level,
5190 btrfs_release_path(path);
5196 /* save our key for returning back */
5197 btrfs_node_key_to_cpu(cur, &found_key, slot);
5198 path->slots[level] = slot;
5199 if (level == path->lowest_level) {
5203 btrfs_set_path_blocking(path);
5204 cur = read_node_slot(root, cur, slot);
5205 BUG_ON(!cur); /* -ENOMEM */
5207 btrfs_tree_read_lock(cur);
5209 path->locks[level - 1] = BTRFS_READ_LOCK;
5210 path->nodes[level - 1] = cur;
5211 unlock_up(path, level, 1, 0, NULL);
5212 btrfs_clear_path_blocking(path, NULL, 0);
5215 path->keep_locks = keep_locks;
5217 btrfs_unlock_up_safe(path, path->lowest_level + 1);
5218 btrfs_set_path_blocking(path);
5219 memcpy(min_key, &found_key, sizeof(found_key));
5224 static void tree_move_down(struct btrfs_root *root,
5225 struct btrfs_path *path,
5226 int *level, int root_level)
5228 BUG_ON(*level == 0);
5229 path->nodes[*level - 1] = read_node_slot(root, path->nodes[*level],
5230 path->slots[*level]);
5231 path->slots[*level - 1] = 0;
5235 static int tree_move_next_or_upnext(struct btrfs_root *root,
5236 struct btrfs_path *path,
5237 int *level, int root_level)
5241 nritems = btrfs_header_nritems(path->nodes[*level]);
5243 path->slots[*level]++;
5245 while (path->slots[*level] >= nritems) {
5246 if (*level == root_level)
5250 path->slots[*level] = 0;
5251 free_extent_buffer(path->nodes[*level]);
5252 path->nodes[*level] = NULL;
5254 path->slots[*level]++;
5256 nritems = btrfs_header_nritems(path->nodes[*level]);
5263 * Returns 1 if it had to move up and next. 0 is returned if it moved only next
5266 static int tree_advance(struct btrfs_root *root,
5267 struct btrfs_path *path,
5268 int *level, int root_level,
5270 struct btrfs_key *key)
5274 if (*level == 0 || !allow_down) {
5275 ret = tree_move_next_or_upnext(root, path, level, root_level);
5277 tree_move_down(root, path, level, root_level);
5282 btrfs_item_key_to_cpu(path->nodes[*level], key,
5283 path->slots[*level]);
5285 btrfs_node_key_to_cpu(path->nodes[*level], key,
5286 path->slots[*level]);
5291 static int tree_compare_item(struct btrfs_root *left_root,
5292 struct btrfs_path *left_path,
5293 struct btrfs_path *right_path,
5298 unsigned long off1, off2;
5300 len1 = btrfs_item_size_nr(left_path->nodes[0], left_path->slots[0]);
5301 len2 = btrfs_item_size_nr(right_path->nodes[0], right_path->slots[0]);
5305 off1 = btrfs_item_ptr_offset(left_path->nodes[0], left_path->slots[0]);
5306 off2 = btrfs_item_ptr_offset(right_path->nodes[0],
5307 right_path->slots[0]);
5309 read_extent_buffer(left_path->nodes[0], tmp_buf, off1, len1);
5311 cmp = memcmp_extent_buffer(right_path->nodes[0], tmp_buf, off2, len1);
5318 #define ADVANCE_ONLY_NEXT -1
5321 * This function compares two trees and calls the provided callback for
5322 * every changed/new/deleted item it finds.
5323 * If shared tree blocks are encountered, whole subtrees are skipped, making
5324 * the compare pretty fast on snapshotted subvolumes.
5326 * This currently works on commit roots only. As commit roots are read only,
5327 * we don't do any locking. The commit roots are protected with transactions.
5328 * Transactions are ended and rejoined when a commit is tried in between.
5330 * This function checks for modifications done to the trees while comparing.
5331 * If it detects a change, it aborts immediately.
5333 int btrfs_compare_trees(struct btrfs_root *left_root,
5334 struct btrfs_root *right_root,
5335 btrfs_changed_cb_t changed_cb, void *ctx)
5339 struct btrfs_path *left_path = NULL;
5340 struct btrfs_path *right_path = NULL;
5341 struct btrfs_key left_key;
5342 struct btrfs_key right_key;
5343 char *tmp_buf = NULL;
5344 int left_root_level;
5345 int right_root_level;
5348 int left_end_reached;
5349 int right_end_reached;
5357 left_path = btrfs_alloc_path();
5362 right_path = btrfs_alloc_path();
5368 tmp_buf = kmalloc(left_root->nodesize, GFP_NOFS);
5374 left_path->search_commit_root = 1;
5375 left_path->skip_locking = 1;
5376 right_path->search_commit_root = 1;
5377 right_path->skip_locking = 1;
5380 * Strategy: Go to the first items of both trees. Then do
5382 * If both trees are at level 0
5383 * Compare keys of current items
5384 * If left < right treat left item as new, advance left tree
5386 * If left > right treat right item as deleted, advance right tree
5388 * If left == right do deep compare of items, treat as changed if
5389 * needed, advance both trees and repeat
5390 * If both trees are at the same level but not at level 0
5391 * Compare keys of current nodes/leafs
5392 * If left < right advance left tree and repeat
5393 * If left > right advance right tree and repeat
5394 * If left == right compare blockptrs of the next nodes/leafs
5395 * If they match advance both trees but stay at the same level
5397 * If they don't match advance both trees while allowing to go
5399 * If tree levels are different
5400 * Advance the tree that needs it and repeat
5402 * Advancing a tree means:
5403 * If we are at level 0, try to go to the next slot. If that's not
5404 * possible, go one level up and repeat. Stop when we found a level
5405 * where we could go to the next slot. We may at this point be on a
5408 * If we are not at level 0 and not on shared tree blocks, go one
5411 * If we are not at level 0 and on shared tree blocks, go one slot to
5412 * the right if possible or go up and right.
5415 down_read(&left_root->fs_info->commit_root_sem);
5416 left_level = btrfs_header_level(left_root->commit_root);
5417 left_root_level = left_level;
5418 left_path->nodes[left_level] = left_root->commit_root;
5419 extent_buffer_get(left_path->nodes[left_level]);
5421 right_level = btrfs_header_level(right_root->commit_root);
5422 right_root_level = right_level;
5423 right_path->nodes[right_level] = right_root->commit_root;
5424 extent_buffer_get(right_path->nodes[right_level]);
5425 up_read(&left_root->fs_info->commit_root_sem);
5427 if (left_level == 0)
5428 btrfs_item_key_to_cpu(left_path->nodes[left_level],
5429 &left_key, left_path->slots[left_level]);
5431 btrfs_node_key_to_cpu(left_path->nodes[left_level],
5432 &left_key, left_path->slots[left_level]);
5433 if (right_level == 0)
5434 btrfs_item_key_to_cpu(right_path->nodes[right_level],
5435 &right_key, right_path->slots[right_level]);
5437 btrfs_node_key_to_cpu(right_path->nodes[right_level],
5438 &right_key, right_path->slots[right_level]);
5440 left_end_reached = right_end_reached = 0;
5441 advance_left = advance_right = 0;
5444 if (advance_left && !left_end_reached) {
5445 ret = tree_advance(left_root, left_path, &left_level,
5447 advance_left != ADVANCE_ONLY_NEXT,
5450 left_end_reached = ADVANCE;
5453 if (advance_right && !right_end_reached) {
5454 ret = tree_advance(right_root, right_path, &right_level,
5456 advance_right != ADVANCE_ONLY_NEXT,
5459 right_end_reached = ADVANCE;
5463 if (left_end_reached && right_end_reached) {
5466 } else if (left_end_reached) {
5467 if (right_level == 0) {
5468 ret = changed_cb(left_root, right_root,
5469 left_path, right_path,
5471 BTRFS_COMPARE_TREE_DELETED,
5476 advance_right = ADVANCE;
5478 } else if (right_end_reached) {
5479 if (left_level == 0) {
5480 ret = changed_cb(left_root, right_root,
5481 left_path, right_path,
5483 BTRFS_COMPARE_TREE_NEW,
5488 advance_left = ADVANCE;
5492 if (left_level == 0 && right_level == 0) {
5493 cmp = btrfs_comp_cpu_keys(&left_key, &right_key);
5495 ret = changed_cb(left_root, right_root,
5496 left_path, right_path,
5498 BTRFS_COMPARE_TREE_NEW,
5502 advance_left = ADVANCE;
5503 } else if (cmp > 0) {
5504 ret = changed_cb(left_root, right_root,
5505 left_path, right_path,
5507 BTRFS_COMPARE_TREE_DELETED,
5511 advance_right = ADVANCE;
5513 enum btrfs_compare_tree_result result;
5515 WARN_ON(!extent_buffer_uptodate(left_path->nodes[0]));
5516 ret = tree_compare_item(left_root, left_path,
5517 right_path, tmp_buf);
5519 result = BTRFS_COMPARE_TREE_CHANGED;
5521 result = BTRFS_COMPARE_TREE_SAME;
5522 ret = changed_cb(left_root, right_root,
5523 left_path, right_path,
5524 &left_key, result, ctx);
5527 advance_left = ADVANCE;
5528 advance_right = ADVANCE;
5530 } else if (left_level == right_level) {
5531 cmp = btrfs_comp_cpu_keys(&left_key, &right_key);
5533 advance_left = ADVANCE;
5534 } else if (cmp > 0) {
5535 advance_right = ADVANCE;
5537 left_blockptr = btrfs_node_blockptr(
5538 left_path->nodes[left_level],
5539 left_path->slots[left_level]);
5540 right_blockptr = btrfs_node_blockptr(
5541 right_path->nodes[right_level],
5542 right_path->slots[right_level]);
5543 left_gen = btrfs_node_ptr_generation(
5544 left_path->nodes[left_level],
5545 left_path->slots[left_level]);
5546 right_gen = btrfs_node_ptr_generation(
5547 right_path->nodes[right_level],
5548 right_path->slots[right_level]);
5549 if (left_blockptr == right_blockptr &&
5550 left_gen == right_gen) {
5552 * As we're on a shared block, don't
5553 * allow to go deeper.
5555 advance_left = ADVANCE_ONLY_NEXT;
5556 advance_right = ADVANCE_ONLY_NEXT;
5558 advance_left = ADVANCE;
5559 advance_right = ADVANCE;
5562 } else if (left_level < right_level) {
5563 advance_right = ADVANCE;
5565 advance_left = ADVANCE;
5570 btrfs_free_path(left_path);
5571 btrfs_free_path(right_path);
5577 * this is similar to btrfs_next_leaf, but does not try to preserve
5578 * and fixup the path. It looks for and returns the next key in the
5579 * tree based on the current path and the min_trans parameters.
5581 * 0 is returned if another key is found, < 0 if there are any errors
5582 * and 1 is returned if there are no higher keys in the tree
5584 * path->keep_locks should be set to 1 on the search made before
5585 * calling this function.
5587 int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
5588 struct btrfs_key *key, int level, u64 min_trans)
5591 struct extent_buffer *c;
5593 WARN_ON(!path->keep_locks);
5594 while (level < BTRFS_MAX_LEVEL) {
5595 if (!path->nodes[level])
5598 slot = path->slots[level] + 1;
5599 c = path->nodes[level];
5601 if (slot >= btrfs_header_nritems(c)) {
5604 struct btrfs_key cur_key;
5605 if (level + 1 >= BTRFS_MAX_LEVEL ||
5606 !path->nodes[level + 1])
5609 if (path->locks[level + 1]) {
5614 slot = btrfs_header_nritems(c) - 1;
5616 btrfs_item_key_to_cpu(c, &cur_key, slot);
5618 btrfs_node_key_to_cpu(c, &cur_key, slot);
5620 orig_lowest = path->lowest_level;
5621 btrfs_release_path(path);
5622 path->lowest_level = level;
5623 ret = btrfs_search_slot(NULL, root, &cur_key, path,
5625 path->lowest_level = orig_lowest;
5629 c = path->nodes[level];
5630 slot = path->slots[level];
5637 btrfs_item_key_to_cpu(c, key, slot);
5639 u64 gen = btrfs_node_ptr_generation(c, slot);
5641 if (gen < min_trans) {
5645 btrfs_node_key_to_cpu(c, key, slot);
5653 * search the tree again to find a leaf with greater keys
5654 * returns 0 if it found something or 1 if there are no greater leaves.
5655 * returns < 0 on io errors.
5657 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
5659 return btrfs_next_old_leaf(root, path, 0);
5662 int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
5667 struct extent_buffer *c;
5668 struct extent_buffer *next;
5669 struct btrfs_key key;
5672 int old_spinning = path->leave_spinning;
5673 int next_rw_lock = 0;
5675 nritems = btrfs_header_nritems(path->nodes[0]);
5679 btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1);
5684 btrfs_release_path(path);
5686 path->keep_locks = 1;
5687 path->leave_spinning = 1;
5690 ret = btrfs_search_old_slot(root, &key, path, time_seq);
5692 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5693 path->keep_locks = 0;
5698 nritems = btrfs_header_nritems(path->nodes[0]);
5700 * by releasing the path above we dropped all our locks. A balance
5701 * could have added more items next to the key that used to be
5702 * at the very end of the block. So, check again here and
5703 * advance the path if there are now more items available.
5705 if (nritems > 0 && path->slots[0] < nritems - 1) {
5712 * So the above check misses one case:
5713 * - after releasing the path above, someone has removed the item that
5714 * used to be at the very end of the block, and balance between leafs
5715 * gets another one with bigger key.offset to replace it.
5717 * This one should be returned as well, or we can get leaf corruption
5718 * later(esp. in __btrfs_drop_extents()).
5720 * And a bit more explanation about this check,
5721 * with ret > 0, the key isn't found, the path points to the slot
5722 * where it should be inserted, so the path->slots[0] item must be the
5725 if (nritems > 0 && ret > 0 && path->slots[0] == nritems - 1) {
5730 while (level < BTRFS_MAX_LEVEL) {
5731 if (!path->nodes[level]) {
5736 slot = path->slots[level] + 1;
5737 c = path->nodes[level];
5738 if (slot >= btrfs_header_nritems(c)) {
5740 if (level == BTRFS_MAX_LEVEL) {
5748 btrfs_tree_unlock_rw(next, next_rw_lock);
5749 free_extent_buffer(next);
5753 next_rw_lock = path->locks[level];
5754 ret = read_block_for_search(NULL, root, path, &next, level,
5760 btrfs_release_path(path);
5764 if (!path->skip_locking) {
5765 ret = btrfs_try_tree_read_lock(next);
5766 if (!ret && time_seq) {
5768 * If we don't get the lock, we may be racing
5769 * with push_leaf_left, holding that lock while
5770 * itself waiting for the leaf we've currently
5771 * locked. To solve this situation, we give up
5772 * on our lock and cycle.
5774 free_extent_buffer(next);
5775 btrfs_release_path(path);
5780 btrfs_set_path_blocking(path);
5781 btrfs_tree_read_lock(next);
5782 btrfs_clear_path_blocking(path, next,
5785 next_rw_lock = BTRFS_READ_LOCK;
5789 path->slots[level] = slot;
5792 c = path->nodes[level];
5793 if (path->locks[level])
5794 btrfs_tree_unlock_rw(c, path->locks[level]);
5796 free_extent_buffer(c);
5797 path->nodes[level] = next;
5798 path->slots[level] = 0;
5799 if (!path->skip_locking)
5800 path->locks[level] = next_rw_lock;
5804 ret = read_block_for_search(NULL, root, path, &next, level,
5810 btrfs_release_path(path);
5814 if (!path->skip_locking) {
5815 ret = btrfs_try_tree_read_lock(next);
5817 btrfs_set_path_blocking(path);
5818 btrfs_tree_read_lock(next);
5819 btrfs_clear_path_blocking(path, next,
5822 next_rw_lock = BTRFS_READ_LOCK;
5827 unlock_up(path, 0, 1, 0, NULL);
5828 path->leave_spinning = old_spinning;
5830 btrfs_set_path_blocking(path);
5836 * this uses btrfs_prev_leaf to walk backwards in the tree, and keeps
5837 * searching until it gets past min_objectid or finds an item of 'type'
5839 * returns 0 if something is found, 1 if nothing was found and < 0 on error
5841 int btrfs_previous_item(struct btrfs_root *root,
5842 struct btrfs_path *path, u64 min_objectid,
5845 struct btrfs_key found_key;
5846 struct extent_buffer *leaf;
5851 if (path->slots[0] == 0) {
5852 btrfs_set_path_blocking(path);
5853 ret = btrfs_prev_leaf(root, path);
5859 leaf = path->nodes[0];
5860 nritems = btrfs_header_nritems(leaf);
5863 if (path->slots[0] == nritems)
5866 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5867 if (found_key.objectid < min_objectid)
5869 if (found_key.type == type)
5871 if (found_key.objectid == min_objectid &&
5872 found_key.type < type)
5879 * search in extent tree to find a previous Metadata/Data extent item with
5882 * returns 0 if something is found, 1 if nothing was found and < 0 on error
5884 int btrfs_previous_extent_item(struct btrfs_root *root,
5885 struct btrfs_path *path, u64 min_objectid)
5887 struct btrfs_key found_key;
5888 struct extent_buffer *leaf;
5893 if (path->slots[0] == 0) {
5894 btrfs_set_path_blocking(path);
5895 ret = btrfs_prev_leaf(root, path);
5901 leaf = path->nodes[0];
5902 nritems = btrfs_header_nritems(leaf);
5905 if (path->slots[0] == nritems)
5908 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5909 if (found_key.objectid < min_objectid)
5911 if (found_key.type == BTRFS_EXTENT_ITEM_KEY ||
5912 found_key.type == BTRFS_METADATA_ITEM_KEY)
5914 if (found_key.objectid == min_objectid &&
5915 found_key.type < BTRFS_EXTENT_ITEM_KEY)