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>
22 #include <linux/vmalloc.h>
25 #include "transaction.h"
26 #include "print-tree.h"
29 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
30 *root, struct btrfs_path *path, int level);
31 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root *root,
32 const struct btrfs_key *ins_key, struct btrfs_path *path,
33 int data_size, int extend);
34 static int push_node_left(struct btrfs_trans_handle *trans,
35 struct btrfs_fs_info *fs_info,
36 struct extent_buffer *dst,
37 struct extent_buffer *src, int empty);
38 static int balance_node_right(struct btrfs_trans_handle *trans,
39 struct btrfs_fs_info *fs_info,
40 struct extent_buffer *dst_buf,
41 struct extent_buffer *src_buf);
42 static void del_ptr(struct btrfs_root *root, struct btrfs_path *path,
44 static int tree_mod_log_free_eb(struct btrfs_fs_info *fs_info,
45 struct extent_buffer *eb);
47 struct btrfs_path *btrfs_alloc_path(void)
49 return 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 COWed 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 struct btrfs_fs_info *fs_info = root->fs_info;
218 if (test_bit(BTRFS_ROOT_DIRTY, &root->state) ||
219 !test_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state))
222 spin_lock(&fs_info->trans_lock);
223 if (!test_and_set_bit(BTRFS_ROOT_DIRTY, &root->state)) {
224 /* Want the extent tree to be the last on the list */
225 if (root->objectid == BTRFS_EXTENT_TREE_OBJECTID)
226 list_move_tail(&root->dirty_list,
227 &fs_info->dirty_cowonly_roots);
229 list_move(&root->dirty_list,
230 &fs_info->dirty_cowonly_roots);
232 spin_unlock(&fs_info->trans_lock);
236 * used by snapshot creation to make a copy of a root for a tree with
237 * a given objectid. The buffer with the new root node is returned in
238 * cow_ret, and this func returns zero on success or a negative error code.
240 int btrfs_copy_root(struct btrfs_trans_handle *trans,
241 struct btrfs_root *root,
242 struct extent_buffer *buf,
243 struct extent_buffer **cow_ret, u64 new_root_objectid)
245 struct btrfs_fs_info *fs_info = root->fs_info;
246 struct extent_buffer *cow;
249 struct btrfs_disk_key disk_key;
251 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
252 trans->transid != fs_info->running_transaction->transid);
253 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
254 trans->transid != root->last_trans);
256 level = btrfs_header_level(buf);
258 btrfs_item_key(buf, &disk_key, 0);
260 btrfs_node_key(buf, &disk_key, 0);
262 cow = btrfs_alloc_tree_block(trans, root, 0, new_root_objectid,
263 &disk_key, level, buf->start, 0);
267 copy_extent_buffer_full(cow, buf);
268 btrfs_set_header_bytenr(cow, cow->start);
269 btrfs_set_header_generation(cow, trans->transid);
270 btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV);
271 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN |
272 BTRFS_HEADER_FLAG_RELOC);
273 if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID)
274 btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC);
276 btrfs_set_header_owner(cow, new_root_objectid);
278 write_extent_buffer_fsid(cow, fs_info->fsid);
280 WARN_ON(btrfs_header_generation(buf) > trans->transid);
281 if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID)
282 ret = btrfs_inc_ref(trans, root, cow, 1);
284 ret = btrfs_inc_ref(trans, root, cow, 0);
289 btrfs_mark_buffer_dirty(cow);
298 MOD_LOG_KEY_REMOVE_WHILE_FREEING,
299 MOD_LOG_KEY_REMOVE_WHILE_MOVING,
301 MOD_LOG_ROOT_REPLACE,
304 struct tree_mod_move {
309 struct tree_mod_root {
314 struct tree_mod_elem {
320 /* this is used for MOD_LOG_KEY_* and MOD_LOG_MOVE_KEYS operations */
323 /* this is used for MOD_LOG_KEY* and MOD_LOG_ROOT_REPLACE */
326 /* those are used for op == MOD_LOG_KEY_{REPLACE,REMOVE} */
327 struct btrfs_disk_key key;
330 /* this is used for op == MOD_LOG_MOVE_KEYS */
331 struct tree_mod_move move;
333 /* this is used for op == MOD_LOG_ROOT_REPLACE */
334 struct tree_mod_root old_root;
337 static inline void tree_mod_log_read_lock(struct btrfs_fs_info *fs_info)
339 read_lock(&fs_info->tree_mod_log_lock);
342 static inline void tree_mod_log_read_unlock(struct btrfs_fs_info *fs_info)
344 read_unlock(&fs_info->tree_mod_log_lock);
347 static inline void tree_mod_log_write_lock(struct btrfs_fs_info *fs_info)
349 write_lock(&fs_info->tree_mod_log_lock);
352 static inline void tree_mod_log_write_unlock(struct btrfs_fs_info *fs_info)
354 write_unlock(&fs_info->tree_mod_log_lock);
358 * Pull a new tree mod seq number for our operation.
360 static inline u64 btrfs_inc_tree_mod_seq(struct btrfs_fs_info *fs_info)
362 return atomic64_inc_return(&fs_info->tree_mod_seq);
366 * This adds a new blocker to the tree mod log's blocker list if the @elem
367 * passed does not already have a sequence number set. So when a caller expects
368 * to record tree modifications, it should ensure to set elem->seq to zero
369 * before calling btrfs_get_tree_mod_seq.
370 * Returns a fresh, unused tree log modification sequence number, even if no new
373 u64 btrfs_get_tree_mod_seq(struct btrfs_fs_info *fs_info,
374 struct seq_list *elem)
376 tree_mod_log_write_lock(fs_info);
377 spin_lock(&fs_info->tree_mod_seq_lock);
379 elem->seq = btrfs_inc_tree_mod_seq(fs_info);
380 list_add_tail(&elem->list, &fs_info->tree_mod_seq_list);
382 spin_unlock(&fs_info->tree_mod_seq_lock);
383 tree_mod_log_write_unlock(fs_info);
388 void btrfs_put_tree_mod_seq(struct btrfs_fs_info *fs_info,
389 struct seq_list *elem)
391 struct rb_root *tm_root;
392 struct rb_node *node;
393 struct rb_node *next;
394 struct seq_list *cur_elem;
395 struct tree_mod_elem *tm;
396 u64 min_seq = (u64)-1;
397 u64 seq_putting = elem->seq;
402 spin_lock(&fs_info->tree_mod_seq_lock);
403 list_del(&elem->list);
406 list_for_each_entry(cur_elem, &fs_info->tree_mod_seq_list, list) {
407 if (cur_elem->seq < min_seq) {
408 if (seq_putting > cur_elem->seq) {
410 * blocker with lower sequence number exists, we
411 * cannot remove anything from the log
413 spin_unlock(&fs_info->tree_mod_seq_lock);
416 min_seq = cur_elem->seq;
419 spin_unlock(&fs_info->tree_mod_seq_lock);
422 * anything that's lower than the lowest existing (read: blocked)
423 * sequence number can be removed from the tree.
425 tree_mod_log_write_lock(fs_info);
426 tm_root = &fs_info->tree_mod_log;
427 for (node = rb_first(tm_root); node; node = next) {
428 next = rb_next(node);
429 tm = rb_entry(node, struct tree_mod_elem, node);
430 if (tm->seq > min_seq)
432 rb_erase(node, tm_root);
435 tree_mod_log_write_unlock(fs_info);
439 * key order of the log:
440 * node/leaf start address -> sequence
442 * The 'start address' is the logical address of the *new* root node
443 * for root replace operations, or the logical address of the affected
444 * block for all other operations.
446 * Note: must be called with write lock (tree_mod_log_write_lock).
449 __tree_mod_log_insert(struct btrfs_fs_info *fs_info, struct tree_mod_elem *tm)
451 struct rb_root *tm_root;
452 struct rb_node **new;
453 struct rb_node *parent = NULL;
454 struct tree_mod_elem *cur;
458 tm->seq = btrfs_inc_tree_mod_seq(fs_info);
460 tm_root = &fs_info->tree_mod_log;
461 new = &tm_root->rb_node;
463 cur = rb_entry(*new, struct tree_mod_elem, node);
465 if (cur->logical < tm->logical)
466 new = &((*new)->rb_left);
467 else if (cur->logical > tm->logical)
468 new = &((*new)->rb_right);
469 else if (cur->seq < tm->seq)
470 new = &((*new)->rb_left);
471 else if (cur->seq > tm->seq)
472 new = &((*new)->rb_right);
477 rb_link_node(&tm->node, parent, new);
478 rb_insert_color(&tm->node, tm_root);
483 * Determines if logging can be omitted. Returns 1 if it can. Otherwise, it
484 * returns zero with the tree_mod_log_lock acquired. The caller must hold
485 * this until all tree mod log insertions are recorded in the rb tree and then
486 * call tree_mod_log_write_unlock() to release.
488 static inline int tree_mod_dont_log(struct btrfs_fs_info *fs_info,
489 struct extent_buffer *eb) {
491 if (list_empty(&(fs_info)->tree_mod_seq_list))
493 if (eb && btrfs_header_level(eb) == 0)
496 tree_mod_log_write_lock(fs_info);
497 if (list_empty(&(fs_info)->tree_mod_seq_list)) {
498 tree_mod_log_write_unlock(fs_info);
505 /* Similar to tree_mod_dont_log, but doesn't acquire any locks. */
506 static inline int tree_mod_need_log(const struct btrfs_fs_info *fs_info,
507 struct extent_buffer *eb)
510 if (list_empty(&(fs_info)->tree_mod_seq_list))
512 if (eb && btrfs_header_level(eb) == 0)
518 static struct tree_mod_elem *
519 alloc_tree_mod_elem(struct extent_buffer *eb, int slot,
520 enum mod_log_op op, gfp_t flags)
522 struct tree_mod_elem *tm;
524 tm = kzalloc(sizeof(*tm), flags);
528 tm->logical = eb->start;
529 if (op != MOD_LOG_KEY_ADD) {
530 btrfs_node_key(eb, &tm->key, slot);
531 tm->blockptr = btrfs_node_blockptr(eb, slot);
535 tm->generation = btrfs_node_ptr_generation(eb, slot);
536 RB_CLEAR_NODE(&tm->node);
542 tree_mod_log_insert_key(struct btrfs_fs_info *fs_info,
543 struct extent_buffer *eb, int slot,
544 enum mod_log_op op, gfp_t flags)
546 struct tree_mod_elem *tm;
549 if (!tree_mod_need_log(fs_info, eb))
552 tm = alloc_tree_mod_elem(eb, slot, op, flags);
556 if (tree_mod_dont_log(fs_info, eb)) {
561 ret = __tree_mod_log_insert(fs_info, tm);
562 tree_mod_log_write_unlock(fs_info);
570 tree_mod_log_insert_move(struct btrfs_fs_info *fs_info,
571 struct extent_buffer *eb, int dst_slot, int src_slot,
572 int nr_items, gfp_t flags)
574 struct tree_mod_elem *tm = NULL;
575 struct tree_mod_elem **tm_list = NULL;
580 if (!tree_mod_need_log(fs_info, eb))
583 tm_list = kcalloc(nr_items, sizeof(struct tree_mod_elem *), flags);
587 tm = kzalloc(sizeof(*tm), flags);
593 tm->logical = eb->start;
595 tm->move.dst_slot = dst_slot;
596 tm->move.nr_items = nr_items;
597 tm->op = MOD_LOG_MOVE_KEYS;
599 for (i = 0; i + dst_slot < src_slot && i < nr_items; i++) {
600 tm_list[i] = alloc_tree_mod_elem(eb, i + dst_slot,
601 MOD_LOG_KEY_REMOVE_WHILE_MOVING, flags);
608 if (tree_mod_dont_log(fs_info, eb))
613 * When we override something during the move, we log these removals.
614 * This can only happen when we move towards the beginning of the
615 * buffer, i.e. dst_slot < src_slot.
617 for (i = 0; i + dst_slot < src_slot && i < nr_items; i++) {
618 ret = __tree_mod_log_insert(fs_info, tm_list[i]);
623 ret = __tree_mod_log_insert(fs_info, tm);
626 tree_mod_log_write_unlock(fs_info);
631 for (i = 0; i < nr_items; i++) {
632 if (tm_list[i] && !RB_EMPTY_NODE(&tm_list[i]->node))
633 rb_erase(&tm_list[i]->node, &fs_info->tree_mod_log);
637 tree_mod_log_write_unlock(fs_info);
645 __tree_mod_log_free_eb(struct btrfs_fs_info *fs_info,
646 struct tree_mod_elem **tm_list,
652 for (i = nritems - 1; i >= 0; i--) {
653 ret = __tree_mod_log_insert(fs_info, tm_list[i]);
655 for (j = nritems - 1; j > i; j--)
656 rb_erase(&tm_list[j]->node,
657 &fs_info->tree_mod_log);
666 tree_mod_log_insert_root(struct btrfs_fs_info *fs_info,
667 struct extent_buffer *old_root,
668 struct extent_buffer *new_root, gfp_t flags,
671 struct tree_mod_elem *tm = NULL;
672 struct tree_mod_elem **tm_list = NULL;
677 if (!tree_mod_need_log(fs_info, NULL))
680 if (log_removal && btrfs_header_level(old_root) > 0) {
681 nritems = btrfs_header_nritems(old_root);
682 tm_list = kcalloc(nritems, sizeof(struct tree_mod_elem *),
688 for (i = 0; i < nritems; i++) {
689 tm_list[i] = alloc_tree_mod_elem(old_root, i,
690 MOD_LOG_KEY_REMOVE_WHILE_FREEING, flags);
698 tm = kzalloc(sizeof(*tm), flags);
704 tm->logical = new_root->start;
705 tm->old_root.logical = old_root->start;
706 tm->old_root.level = btrfs_header_level(old_root);
707 tm->generation = btrfs_header_generation(old_root);
708 tm->op = MOD_LOG_ROOT_REPLACE;
710 if (tree_mod_dont_log(fs_info, NULL))
714 ret = __tree_mod_log_free_eb(fs_info, tm_list, nritems);
716 ret = __tree_mod_log_insert(fs_info, tm);
718 tree_mod_log_write_unlock(fs_info);
727 for (i = 0; i < nritems; i++)
736 static struct tree_mod_elem *
737 __tree_mod_log_search(struct btrfs_fs_info *fs_info, u64 start, u64 min_seq,
740 struct rb_root *tm_root;
741 struct rb_node *node;
742 struct tree_mod_elem *cur = NULL;
743 struct tree_mod_elem *found = NULL;
745 tree_mod_log_read_lock(fs_info);
746 tm_root = &fs_info->tree_mod_log;
747 node = tm_root->rb_node;
749 cur = rb_entry(node, struct tree_mod_elem, node);
750 if (cur->logical < start) {
751 node = node->rb_left;
752 } else if (cur->logical > start) {
753 node = node->rb_right;
754 } else if (cur->seq < min_seq) {
755 node = node->rb_left;
756 } else if (!smallest) {
757 /* we want the node with the highest seq */
759 BUG_ON(found->seq > cur->seq);
761 node = node->rb_left;
762 } else if (cur->seq > min_seq) {
763 /* we want the node with the smallest seq */
765 BUG_ON(found->seq < cur->seq);
767 node = node->rb_right;
773 tree_mod_log_read_unlock(fs_info);
779 * this returns the element from the log with the smallest time sequence
780 * value that's in the log (the oldest log item). any element with a time
781 * sequence lower than min_seq will be ignored.
783 static struct tree_mod_elem *
784 tree_mod_log_search_oldest(struct btrfs_fs_info *fs_info, u64 start,
787 return __tree_mod_log_search(fs_info, start, min_seq, 1);
791 * this returns the element from the log with the largest time sequence
792 * value that's in the log (the most recent log item). any element with
793 * a time sequence lower than min_seq will be ignored.
795 static struct tree_mod_elem *
796 tree_mod_log_search(struct btrfs_fs_info *fs_info, u64 start, u64 min_seq)
798 return __tree_mod_log_search(fs_info, start, min_seq, 0);
802 tree_mod_log_eb_copy(struct btrfs_fs_info *fs_info, struct extent_buffer *dst,
803 struct extent_buffer *src, unsigned long dst_offset,
804 unsigned long src_offset, int nr_items)
807 struct tree_mod_elem **tm_list = NULL;
808 struct tree_mod_elem **tm_list_add, **tm_list_rem;
812 if (!tree_mod_need_log(fs_info, NULL))
815 if (btrfs_header_level(dst) == 0 && btrfs_header_level(src) == 0)
818 tm_list = kcalloc(nr_items * 2, sizeof(struct tree_mod_elem *),
823 tm_list_add = tm_list;
824 tm_list_rem = tm_list + nr_items;
825 for (i = 0; i < nr_items; i++) {
826 tm_list_rem[i] = alloc_tree_mod_elem(src, i + src_offset,
827 MOD_LOG_KEY_REMOVE, GFP_NOFS);
828 if (!tm_list_rem[i]) {
833 tm_list_add[i] = alloc_tree_mod_elem(dst, i + dst_offset,
834 MOD_LOG_KEY_ADD, GFP_NOFS);
835 if (!tm_list_add[i]) {
841 if (tree_mod_dont_log(fs_info, NULL))
845 for (i = 0; i < nr_items; i++) {
846 ret = __tree_mod_log_insert(fs_info, tm_list_rem[i]);
849 ret = __tree_mod_log_insert(fs_info, tm_list_add[i]);
854 tree_mod_log_write_unlock(fs_info);
860 for (i = 0; i < nr_items * 2; i++) {
861 if (tm_list[i] && !RB_EMPTY_NODE(&tm_list[i]->node))
862 rb_erase(&tm_list[i]->node, &fs_info->tree_mod_log);
866 tree_mod_log_write_unlock(fs_info);
873 tree_mod_log_eb_move(struct btrfs_fs_info *fs_info, struct extent_buffer *dst,
874 int dst_offset, int src_offset, int nr_items)
877 ret = tree_mod_log_insert_move(fs_info, dst, dst_offset, src_offset,
883 tree_mod_log_set_node_key(struct btrfs_fs_info *fs_info,
884 struct extent_buffer *eb, int slot, int atomic)
888 ret = tree_mod_log_insert_key(fs_info, eb, slot,
890 atomic ? GFP_ATOMIC : GFP_NOFS);
895 tree_mod_log_free_eb(struct btrfs_fs_info *fs_info, struct extent_buffer *eb)
897 struct tree_mod_elem **tm_list = NULL;
902 if (btrfs_header_level(eb) == 0)
905 if (!tree_mod_need_log(fs_info, NULL))
908 nritems = btrfs_header_nritems(eb);
909 tm_list = kcalloc(nritems, sizeof(struct tree_mod_elem *), GFP_NOFS);
913 for (i = 0; i < nritems; i++) {
914 tm_list[i] = alloc_tree_mod_elem(eb, i,
915 MOD_LOG_KEY_REMOVE_WHILE_FREEING, GFP_NOFS);
922 if (tree_mod_dont_log(fs_info, eb))
925 ret = __tree_mod_log_free_eb(fs_info, tm_list, nritems);
926 tree_mod_log_write_unlock(fs_info);
934 for (i = 0; i < nritems; i++)
942 tree_mod_log_set_root_pointer(struct btrfs_root *root,
943 struct extent_buffer *new_root_node,
947 ret = tree_mod_log_insert_root(root->fs_info, root->node,
948 new_root_node, GFP_NOFS, log_removal);
953 * check if the tree block can be shared by multiple trees
955 int btrfs_block_can_be_shared(struct btrfs_root *root,
956 struct extent_buffer *buf)
959 * Tree blocks not in reference counted trees and tree roots
960 * are never shared. If a block was allocated after the last
961 * snapshot and the block was not allocated by tree relocation,
962 * we know the block is not shared.
964 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
965 buf != root->node && buf != root->commit_root &&
966 (btrfs_header_generation(buf) <=
967 btrfs_root_last_snapshot(&root->root_item) ||
968 btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)))
970 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
971 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
972 btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
978 static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans,
979 struct btrfs_root *root,
980 struct extent_buffer *buf,
981 struct extent_buffer *cow,
984 struct btrfs_fs_info *fs_info = root->fs_info;
992 * Backrefs update rules:
994 * Always use full backrefs for extent pointers in tree block
995 * allocated by tree relocation.
997 * If a shared tree block is no longer referenced by its owner
998 * tree (btrfs_header_owner(buf) == root->root_key.objectid),
999 * use full backrefs for extent pointers in tree block.
1001 * If a tree block is been relocating
1002 * (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID),
1003 * use full backrefs for extent pointers in tree block.
1004 * The reason for this is some operations (such as drop tree)
1005 * are only allowed for blocks use full backrefs.
1008 if (btrfs_block_can_be_shared(root, buf)) {
1009 ret = btrfs_lookup_extent_info(trans, fs_info, buf->start,
1010 btrfs_header_level(buf), 1,
1016 btrfs_handle_fs_error(fs_info, ret, NULL);
1021 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
1022 btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
1023 flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
1028 owner = btrfs_header_owner(buf);
1029 BUG_ON(owner == BTRFS_TREE_RELOC_OBJECTID &&
1030 !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
1033 if ((owner == root->root_key.objectid ||
1034 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) &&
1035 !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) {
1036 ret = btrfs_inc_ref(trans, root, buf, 1);
1037 BUG_ON(ret); /* -ENOMEM */
1039 if (root->root_key.objectid ==
1040 BTRFS_TREE_RELOC_OBJECTID) {
1041 ret = btrfs_dec_ref(trans, root, buf, 0);
1042 BUG_ON(ret); /* -ENOMEM */
1043 ret = btrfs_inc_ref(trans, root, cow, 1);
1044 BUG_ON(ret); /* -ENOMEM */
1046 new_flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
1049 if (root->root_key.objectid ==
1050 BTRFS_TREE_RELOC_OBJECTID)
1051 ret = btrfs_inc_ref(trans, root, cow, 1);
1053 ret = btrfs_inc_ref(trans, root, cow, 0);
1054 BUG_ON(ret); /* -ENOMEM */
1056 if (new_flags != 0) {
1057 int level = btrfs_header_level(buf);
1059 ret = btrfs_set_disk_extent_flags(trans, fs_info,
1062 new_flags, level, 0);
1067 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
1068 if (root->root_key.objectid ==
1069 BTRFS_TREE_RELOC_OBJECTID)
1070 ret = btrfs_inc_ref(trans, root, cow, 1);
1072 ret = btrfs_inc_ref(trans, root, cow, 0);
1073 BUG_ON(ret); /* -ENOMEM */
1074 ret = btrfs_dec_ref(trans, root, buf, 1);
1075 BUG_ON(ret); /* -ENOMEM */
1077 clean_tree_block(fs_info, buf);
1084 * does the dirty work in cow of a single block. The parent block (if
1085 * supplied) is updated to point to the new cow copy. The new buffer is marked
1086 * dirty and returned locked. If you modify the block it needs to be marked
1089 * search_start -- an allocation hint for the new block
1091 * empty_size -- a hint that you plan on doing more cow. This is the size in
1092 * bytes the allocator should try to find free next to the block it returns.
1093 * This is just a hint and may be ignored by the allocator.
1095 static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
1096 struct btrfs_root *root,
1097 struct extent_buffer *buf,
1098 struct extent_buffer *parent, int parent_slot,
1099 struct extent_buffer **cow_ret,
1100 u64 search_start, u64 empty_size)
1102 struct btrfs_fs_info *fs_info = root->fs_info;
1103 struct btrfs_disk_key disk_key;
1104 struct extent_buffer *cow;
1107 int unlock_orig = 0;
1108 u64 parent_start = 0;
1110 if (*cow_ret == buf)
1113 btrfs_assert_tree_locked(buf);
1115 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
1116 trans->transid != fs_info->running_transaction->transid);
1117 WARN_ON(test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
1118 trans->transid != root->last_trans);
1120 level = btrfs_header_level(buf);
1123 btrfs_item_key(buf, &disk_key, 0);
1125 btrfs_node_key(buf, &disk_key, 0);
1127 if ((root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) && parent)
1128 parent_start = parent->start;
1130 cow = btrfs_alloc_tree_block(trans, root, parent_start,
1131 root->root_key.objectid, &disk_key, level,
1132 search_start, empty_size);
1134 return PTR_ERR(cow);
1136 /* cow is set to blocking by btrfs_init_new_buffer */
1138 copy_extent_buffer_full(cow, buf);
1139 btrfs_set_header_bytenr(cow, cow->start);
1140 btrfs_set_header_generation(cow, trans->transid);
1141 btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV);
1142 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN |
1143 BTRFS_HEADER_FLAG_RELOC);
1144 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1145 btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC);
1147 btrfs_set_header_owner(cow, root->root_key.objectid);
1149 write_extent_buffer_fsid(cow, fs_info->fsid);
1151 ret = update_ref_for_cow(trans, root, buf, cow, &last_ref);
1153 btrfs_abort_transaction(trans, ret);
1157 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
1158 ret = btrfs_reloc_cow_block(trans, root, buf, cow);
1160 btrfs_abort_transaction(trans, ret);
1165 if (buf == root->node) {
1166 WARN_ON(parent && parent != buf);
1167 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
1168 btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
1169 parent_start = buf->start;
1171 extent_buffer_get(cow);
1172 tree_mod_log_set_root_pointer(root, cow, 1);
1173 rcu_assign_pointer(root->node, cow);
1175 btrfs_free_tree_block(trans, root, buf, parent_start,
1177 free_extent_buffer(buf);
1178 add_root_to_dirty_list(root);
1180 WARN_ON(trans->transid != btrfs_header_generation(parent));
1181 tree_mod_log_insert_key(fs_info, parent, parent_slot,
1182 MOD_LOG_KEY_REPLACE, GFP_NOFS);
1183 btrfs_set_node_blockptr(parent, parent_slot,
1185 btrfs_set_node_ptr_generation(parent, parent_slot,
1187 btrfs_mark_buffer_dirty(parent);
1189 ret = tree_mod_log_free_eb(fs_info, buf);
1191 btrfs_abort_transaction(trans, ret);
1195 btrfs_free_tree_block(trans, root, buf, parent_start,
1199 btrfs_tree_unlock(buf);
1200 free_extent_buffer_stale(buf);
1201 btrfs_mark_buffer_dirty(cow);
1207 * returns the logical address of the oldest predecessor of the given root.
1208 * entries older than time_seq are ignored.
1210 static struct tree_mod_elem *
1211 __tree_mod_log_oldest_root(struct btrfs_fs_info *fs_info,
1212 struct extent_buffer *eb_root, u64 time_seq)
1214 struct tree_mod_elem *tm;
1215 struct tree_mod_elem *found = NULL;
1216 u64 root_logical = eb_root->start;
1223 * the very last operation that's logged for a root is the
1224 * replacement operation (if it is replaced at all). this has
1225 * the logical address of the *new* root, making it the very
1226 * first operation that's logged for this root.
1229 tm = tree_mod_log_search_oldest(fs_info, root_logical,
1234 * if there are no tree operation for the oldest root, we simply
1235 * return it. this should only happen if that (old) root is at
1242 * if there's an operation that's not a root replacement, we
1243 * found the oldest version of our root. normally, we'll find a
1244 * MOD_LOG_KEY_REMOVE_WHILE_FREEING operation here.
1246 if (tm->op != MOD_LOG_ROOT_REPLACE)
1250 root_logical = tm->old_root.logical;
1254 /* if there's no old root to return, return what we found instead */
1262 * tm is a pointer to the first operation to rewind within eb. then, all
1263 * previous operations will be rewound (until we reach something older than
1267 __tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct extent_buffer *eb,
1268 u64 time_seq, struct tree_mod_elem *first_tm)
1271 struct rb_node *next;
1272 struct tree_mod_elem *tm = first_tm;
1273 unsigned long o_dst;
1274 unsigned long o_src;
1275 unsigned long p_size = sizeof(struct btrfs_key_ptr);
1277 n = btrfs_header_nritems(eb);
1278 tree_mod_log_read_lock(fs_info);
1279 while (tm && tm->seq >= time_seq) {
1281 * all the operations are recorded with the operator used for
1282 * the modification. as we're going backwards, we do the
1283 * opposite of each operation here.
1286 case MOD_LOG_KEY_REMOVE_WHILE_FREEING:
1287 BUG_ON(tm->slot < n);
1289 case MOD_LOG_KEY_REMOVE_WHILE_MOVING:
1290 case MOD_LOG_KEY_REMOVE:
1291 btrfs_set_node_key(eb, &tm->key, tm->slot);
1292 btrfs_set_node_blockptr(eb, tm->slot, tm->blockptr);
1293 btrfs_set_node_ptr_generation(eb, tm->slot,
1297 case MOD_LOG_KEY_REPLACE:
1298 BUG_ON(tm->slot >= n);
1299 btrfs_set_node_key(eb, &tm->key, tm->slot);
1300 btrfs_set_node_blockptr(eb, tm->slot, tm->blockptr);
1301 btrfs_set_node_ptr_generation(eb, tm->slot,
1304 case MOD_LOG_KEY_ADD:
1305 /* if a move operation is needed it's in the log */
1308 case MOD_LOG_MOVE_KEYS:
1309 o_dst = btrfs_node_key_ptr_offset(tm->slot);
1310 o_src = btrfs_node_key_ptr_offset(tm->move.dst_slot);
1311 memmove_extent_buffer(eb, o_dst, o_src,
1312 tm->move.nr_items * p_size);
1314 case MOD_LOG_ROOT_REPLACE:
1316 * this operation is special. for roots, this must be
1317 * handled explicitly before rewinding.
1318 * for non-roots, this operation may exist if the node
1319 * was a root: root A -> child B; then A gets empty and
1320 * B is promoted to the new root. in the mod log, we'll
1321 * have a root-replace operation for B, a tree block
1322 * that is no root. we simply ignore that operation.
1326 next = rb_next(&tm->node);
1329 tm = rb_entry(next, struct tree_mod_elem, node);
1330 if (tm->logical != first_tm->logical)
1333 tree_mod_log_read_unlock(fs_info);
1334 btrfs_set_header_nritems(eb, n);
1338 * Called with eb read locked. If the buffer cannot be rewound, the same buffer
1339 * is returned. If rewind operations happen, a fresh buffer is returned. The
1340 * returned buffer is always read-locked. If the returned buffer is not the
1341 * input buffer, the lock on the input buffer is released and the input buffer
1342 * is freed (its refcount is decremented).
1344 static struct extent_buffer *
1345 tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct btrfs_path *path,
1346 struct extent_buffer *eb, u64 time_seq)
1348 struct extent_buffer *eb_rewin;
1349 struct tree_mod_elem *tm;
1354 if (btrfs_header_level(eb) == 0)
1357 tm = tree_mod_log_search(fs_info, eb->start, time_seq);
1361 btrfs_set_path_blocking(path);
1362 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
1364 if (tm->op == MOD_LOG_KEY_REMOVE_WHILE_FREEING) {
1365 BUG_ON(tm->slot != 0);
1366 eb_rewin = alloc_dummy_extent_buffer(fs_info, eb->start);
1368 btrfs_tree_read_unlock_blocking(eb);
1369 free_extent_buffer(eb);
1372 btrfs_set_header_bytenr(eb_rewin, eb->start);
1373 btrfs_set_header_backref_rev(eb_rewin,
1374 btrfs_header_backref_rev(eb));
1375 btrfs_set_header_owner(eb_rewin, btrfs_header_owner(eb));
1376 btrfs_set_header_level(eb_rewin, btrfs_header_level(eb));
1378 eb_rewin = btrfs_clone_extent_buffer(eb);
1380 btrfs_tree_read_unlock_blocking(eb);
1381 free_extent_buffer(eb);
1386 btrfs_clear_path_blocking(path, NULL, BTRFS_READ_LOCK);
1387 btrfs_tree_read_unlock_blocking(eb);
1388 free_extent_buffer(eb);
1390 extent_buffer_get(eb_rewin);
1391 btrfs_tree_read_lock(eb_rewin);
1392 __tree_mod_log_rewind(fs_info, eb_rewin, time_seq, tm);
1393 WARN_ON(btrfs_header_nritems(eb_rewin) >
1394 BTRFS_NODEPTRS_PER_BLOCK(fs_info));
1400 * get_old_root() rewinds the state of @root's root node to the given @time_seq
1401 * value. If there are no changes, the current root->root_node is returned. If
1402 * anything changed in between, there's a fresh buffer allocated on which the
1403 * rewind operations are done. In any case, the returned buffer is read locked.
1404 * Returns NULL on error (with no locks held).
1406 static inline struct extent_buffer *
1407 get_old_root(struct btrfs_root *root, u64 time_seq)
1409 struct btrfs_fs_info *fs_info = root->fs_info;
1410 struct tree_mod_elem *tm;
1411 struct extent_buffer *eb = NULL;
1412 struct extent_buffer *eb_root;
1413 struct extent_buffer *old;
1414 struct tree_mod_root *old_root = NULL;
1415 u64 old_generation = 0;
1418 eb_root = btrfs_read_lock_root_node(root);
1419 tm = __tree_mod_log_oldest_root(fs_info, eb_root, time_seq);
1423 if (tm->op == MOD_LOG_ROOT_REPLACE) {
1424 old_root = &tm->old_root;
1425 old_generation = tm->generation;
1426 logical = old_root->logical;
1428 logical = eb_root->start;
1431 tm = tree_mod_log_search(fs_info, logical, time_seq);
1432 if (old_root && tm && tm->op != MOD_LOG_KEY_REMOVE_WHILE_FREEING) {
1433 btrfs_tree_read_unlock(eb_root);
1434 free_extent_buffer(eb_root);
1435 old = read_tree_block(fs_info, logical, 0);
1436 if (WARN_ON(IS_ERR(old) || !extent_buffer_uptodate(old))) {
1438 free_extent_buffer(old);
1440 "failed to read tree block %llu from get_old_root",
1443 eb = btrfs_clone_extent_buffer(old);
1444 free_extent_buffer(old);
1446 } else if (old_root) {
1447 btrfs_tree_read_unlock(eb_root);
1448 free_extent_buffer(eb_root);
1449 eb = alloc_dummy_extent_buffer(fs_info, logical);
1451 btrfs_set_lock_blocking_rw(eb_root, BTRFS_READ_LOCK);
1452 eb = btrfs_clone_extent_buffer(eb_root);
1453 btrfs_tree_read_unlock_blocking(eb_root);
1454 free_extent_buffer(eb_root);
1459 extent_buffer_get(eb);
1460 btrfs_tree_read_lock(eb);
1462 btrfs_set_header_bytenr(eb, eb->start);
1463 btrfs_set_header_backref_rev(eb, BTRFS_MIXED_BACKREF_REV);
1464 btrfs_set_header_owner(eb, btrfs_header_owner(eb_root));
1465 btrfs_set_header_level(eb, old_root->level);
1466 btrfs_set_header_generation(eb, old_generation);
1469 __tree_mod_log_rewind(fs_info, eb, time_seq, tm);
1471 WARN_ON(btrfs_header_level(eb) != 0);
1472 WARN_ON(btrfs_header_nritems(eb) > BTRFS_NODEPTRS_PER_BLOCK(fs_info));
1477 int btrfs_old_root_level(struct btrfs_root *root, u64 time_seq)
1479 struct tree_mod_elem *tm;
1481 struct extent_buffer *eb_root = btrfs_root_node(root);
1483 tm = __tree_mod_log_oldest_root(root->fs_info, eb_root, time_seq);
1484 if (tm && tm->op == MOD_LOG_ROOT_REPLACE) {
1485 level = tm->old_root.level;
1487 level = btrfs_header_level(eb_root);
1489 free_extent_buffer(eb_root);
1494 static inline int should_cow_block(struct btrfs_trans_handle *trans,
1495 struct btrfs_root *root,
1496 struct extent_buffer *buf)
1498 if (btrfs_is_testing(root->fs_info))
1501 /* ensure we can see the force_cow */
1505 * We do not need to cow a block if
1506 * 1) this block is not created or changed in this transaction;
1507 * 2) this block does not belong to TREE_RELOC tree;
1508 * 3) the root is not forced COW.
1510 * What is forced COW:
1511 * when we create snapshot during committing the transaction,
1512 * after we've finished coping src root, we must COW the shared
1513 * block to ensure the metadata consistency.
1515 if (btrfs_header_generation(buf) == trans->transid &&
1516 !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN) &&
1517 !(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID &&
1518 btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)) &&
1519 !test_bit(BTRFS_ROOT_FORCE_COW, &root->state))
1525 * cows a single block, see __btrfs_cow_block for the real work.
1526 * This version of it has extra checks so that a block isn't COWed more than
1527 * once per transaction, as long as it hasn't been written yet
1529 noinline int btrfs_cow_block(struct btrfs_trans_handle *trans,
1530 struct btrfs_root *root, struct extent_buffer *buf,
1531 struct extent_buffer *parent, int parent_slot,
1532 struct extent_buffer **cow_ret)
1534 struct btrfs_fs_info *fs_info = root->fs_info;
1538 if (trans->transaction != fs_info->running_transaction)
1539 WARN(1, KERN_CRIT "trans %llu running %llu\n",
1541 fs_info->running_transaction->transid);
1543 if (trans->transid != fs_info->generation)
1544 WARN(1, KERN_CRIT "trans %llu running %llu\n",
1545 trans->transid, fs_info->generation);
1547 if (!should_cow_block(trans, root, buf)) {
1548 trans->dirty = true;
1553 search_start = buf->start & ~((u64)SZ_1G - 1);
1556 btrfs_set_lock_blocking(parent);
1557 btrfs_set_lock_blocking(buf);
1559 ret = __btrfs_cow_block(trans, root, buf, parent,
1560 parent_slot, cow_ret, search_start, 0);
1562 trace_btrfs_cow_block(root, buf, *cow_ret);
1568 * helper function for defrag to decide if two blocks pointed to by a
1569 * node are actually close by
1571 static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
1573 if (blocknr < other && other - (blocknr + blocksize) < 32768)
1575 if (blocknr > other && blocknr - (other + blocksize) < 32768)
1581 * compare two keys in a memcmp fashion
1583 static int comp_keys(const struct btrfs_disk_key *disk,
1584 const struct btrfs_key *k2)
1586 struct btrfs_key k1;
1588 btrfs_disk_key_to_cpu(&k1, disk);
1590 return btrfs_comp_cpu_keys(&k1, k2);
1594 * same as comp_keys only with two btrfs_key's
1596 int btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2)
1598 if (k1->objectid > k2->objectid)
1600 if (k1->objectid < k2->objectid)
1602 if (k1->type > k2->type)
1604 if (k1->type < k2->type)
1606 if (k1->offset > k2->offset)
1608 if (k1->offset < k2->offset)
1614 * this is used by the defrag code to go through all the
1615 * leaves pointed to by a node and reallocate them so that
1616 * disk order is close to key order
1618 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
1619 struct btrfs_root *root, struct extent_buffer *parent,
1620 int start_slot, u64 *last_ret,
1621 struct btrfs_key *progress)
1623 struct btrfs_fs_info *fs_info = root->fs_info;
1624 struct extent_buffer *cur;
1627 u64 search_start = *last_ret;
1637 int progress_passed = 0;
1638 struct btrfs_disk_key disk_key;
1640 parent_level = btrfs_header_level(parent);
1642 WARN_ON(trans->transaction != fs_info->running_transaction);
1643 WARN_ON(trans->transid != fs_info->generation);
1645 parent_nritems = btrfs_header_nritems(parent);
1646 blocksize = fs_info->nodesize;
1647 end_slot = parent_nritems - 1;
1649 if (parent_nritems <= 1)
1652 btrfs_set_lock_blocking(parent);
1654 for (i = start_slot; i <= end_slot; i++) {
1657 btrfs_node_key(parent, &disk_key, i);
1658 if (!progress_passed && comp_keys(&disk_key, progress) < 0)
1661 progress_passed = 1;
1662 blocknr = btrfs_node_blockptr(parent, i);
1663 gen = btrfs_node_ptr_generation(parent, i);
1664 if (last_block == 0)
1665 last_block = blocknr;
1668 other = btrfs_node_blockptr(parent, i - 1);
1669 close = close_blocks(blocknr, other, blocksize);
1671 if (!close && i < end_slot) {
1672 other = btrfs_node_blockptr(parent, i + 1);
1673 close = close_blocks(blocknr, other, blocksize);
1676 last_block = blocknr;
1680 cur = find_extent_buffer(fs_info, blocknr);
1682 uptodate = btrfs_buffer_uptodate(cur, gen, 0);
1685 if (!cur || !uptodate) {
1687 cur = read_tree_block(fs_info, blocknr, gen);
1689 return PTR_ERR(cur);
1690 } else if (!extent_buffer_uptodate(cur)) {
1691 free_extent_buffer(cur);
1694 } else if (!uptodate) {
1695 err = btrfs_read_buffer(cur, gen);
1697 free_extent_buffer(cur);
1702 if (search_start == 0)
1703 search_start = last_block;
1705 btrfs_tree_lock(cur);
1706 btrfs_set_lock_blocking(cur);
1707 err = __btrfs_cow_block(trans, root, cur, parent, i,
1710 (end_slot - i) * blocksize));
1712 btrfs_tree_unlock(cur);
1713 free_extent_buffer(cur);
1716 search_start = cur->start;
1717 last_block = cur->start;
1718 *last_ret = search_start;
1719 btrfs_tree_unlock(cur);
1720 free_extent_buffer(cur);
1726 * search for key in the extent_buffer. The items start at offset p,
1727 * and they are item_size apart. There are 'max' items in p.
1729 * the slot in the array is returned via slot, and it points to
1730 * the place where you would insert key if it is not found in
1733 * slot may point to max if the key is bigger than all of the keys
1735 static noinline int generic_bin_search(struct extent_buffer *eb,
1736 unsigned long p, int item_size,
1737 const struct btrfs_key *key,
1744 struct btrfs_disk_key *tmp = NULL;
1745 struct btrfs_disk_key unaligned;
1746 unsigned long offset;
1748 unsigned long map_start = 0;
1749 unsigned long map_len = 0;
1753 btrfs_err(eb->fs_info,
1754 "%s: low (%d) > high (%d) eb %llu owner %llu level %d",
1755 __func__, low, high, eb->start,
1756 btrfs_header_owner(eb), btrfs_header_level(eb));
1760 while (low < high) {
1761 mid = (low + high) / 2;
1762 offset = p + mid * item_size;
1764 if (!kaddr || offset < map_start ||
1765 (offset + sizeof(struct btrfs_disk_key)) >
1766 map_start + map_len) {
1768 err = map_private_extent_buffer(eb, offset,
1769 sizeof(struct btrfs_disk_key),
1770 &kaddr, &map_start, &map_len);
1773 tmp = (struct btrfs_disk_key *)(kaddr + offset -
1775 } else if (err == 1) {
1776 read_extent_buffer(eb, &unaligned,
1777 offset, sizeof(unaligned));
1784 tmp = (struct btrfs_disk_key *)(kaddr + offset -
1787 ret = comp_keys(tmp, key);
1803 * simple bin_search frontend that does the right thing for
1806 static int bin_search(struct extent_buffer *eb, const struct btrfs_key *key,
1807 int level, int *slot)
1810 return generic_bin_search(eb,
1811 offsetof(struct btrfs_leaf, items),
1812 sizeof(struct btrfs_item),
1813 key, btrfs_header_nritems(eb),
1816 return generic_bin_search(eb,
1817 offsetof(struct btrfs_node, ptrs),
1818 sizeof(struct btrfs_key_ptr),
1819 key, btrfs_header_nritems(eb),
1823 int btrfs_bin_search(struct extent_buffer *eb, const struct btrfs_key *key,
1824 int level, int *slot)
1826 return bin_search(eb, key, level, slot);
1829 static void root_add_used(struct btrfs_root *root, u32 size)
1831 spin_lock(&root->accounting_lock);
1832 btrfs_set_root_used(&root->root_item,
1833 btrfs_root_used(&root->root_item) + size);
1834 spin_unlock(&root->accounting_lock);
1837 static void root_sub_used(struct btrfs_root *root, u32 size)
1839 spin_lock(&root->accounting_lock);
1840 btrfs_set_root_used(&root->root_item,
1841 btrfs_root_used(&root->root_item) - size);
1842 spin_unlock(&root->accounting_lock);
1845 /* given a node and slot number, this reads the blocks it points to. The
1846 * extent buffer is returned with a reference taken (but unlocked).
1848 static noinline struct extent_buffer *
1849 read_node_slot(struct btrfs_fs_info *fs_info, struct extent_buffer *parent,
1852 int level = btrfs_header_level(parent);
1853 struct extent_buffer *eb;
1855 if (slot < 0 || slot >= btrfs_header_nritems(parent))
1856 return ERR_PTR(-ENOENT);
1860 eb = read_tree_block(fs_info, btrfs_node_blockptr(parent, slot),
1861 btrfs_node_ptr_generation(parent, slot));
1862 if (!IS_ERR(eb) && !extent_buffer_uptodate(eb)) {
1863 free_extent_buffer(eb);
1871 * node level balancing, used to make sure nodes are in proper order for
1872 * item deletion. We balance from the top down, so we have to make sure
1873 * that a deletion won't leave an node completely empty later on.
1875 static noinline int balance_level(struct btrfs_trans_handle *trans,
1876 struct btrfs_root *root,
1877 struct btrfs_path *path, int level)
1879 struct btrfs_fs_info *fs_info = root->fs_info;
1880 struct extent_buffer *right = NULL;
1881 struct extent_buffer *mid;
1882 struct extent_buffer *left = NULL;
1883 struct extent_buffer *parent = NULL;
1887 int orig_slot = path->slots[level];
1893 mid = path->nodes[level];
1895 WARN_ON(path->locks[level] != BTRFS_WRITE_LOCK &&
1896 path->locks[level] != BTRFS_WRITE_LOCK_BLOCKING);
1897 WARN_ON(btrfs_header_generation(mid) != trans->transid);
1899 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
1901 if (level < BTRFS_MAX_LEVEL - 1) {
1902 parent = path->nodes[level + 1];
1903 pslot = path->slots[level + 1];
1907 * deal with the case where there is only one pointer in the root
1908 * by promoting the node below to a root
1911 struct extent_buffer *child;
1913 if (btrfs_header_nritems(mid) != 1)
1916 /* promote the child to a root */
1917 child = read_node_slot(fs_info, mid, 0);
1918 if (IS_ERR(child)) {
1919 ret = PTR_ERR(child);
1920 btrfs_handle_fs_error(fs_info, ret, NULL);
1924 btrfs_tree_lock(child);
1925 btrfs_set_lock_blocking(child);
1926 ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
1928 btrfs_tree_unlock(child);
1929 free_extent_buffer(child);
1933 tree_mod_log_set_root_pointer(root, child, 1);
1934 rcu_assign_pointer(root->node, child);
1936 add_root_to_dirty_list(root);
1937 btrfs_tree_unlock(child);
1939 path->locks[level] = 0;
1940 path->nodes[level] = NULL;
1941 clean_tree_block(fs_info, mid);
1942 btrfs_tree_unlock(mid);
1943 /* once for the path */
1944 free_extent_buffer(mid);
1946 root_sub_used(root, mid->len);
1947 btrfs_free_tree_block(trans, root, mid, 0, 1);
1948 /* once for the root ptr */
1949 free_extent_buffer_stale(mid);
1952 if (btrfs_header_nritems(mid) >
1953 BTRFS_NODEPTRS_PER_BLOCK(fs_info) / 4)
1956 left = read_node_slot(fs_info, parent, pslot - 1);
1961 btrfs_tree_lock(left);
1962 btrfs_set_lock_blocking(left);
1963 wret = btrfs_cow_block(trans, root, left,
1964 parent, pslot - 1, &left);
1971 right = read_node_slot(fs_info, parent, pslot + 1);
1976 btrfs_tree_lock(right);
1977 btrfs_set_lock_blocking(right);
1978 wret = btrfs_cow_block(trans, root, right,
1979 parent, pslot + 1, &right);
1986 /* first, try to make some room in the middle buffer */
1988 orig_slot += btrfs_header_nritems(left);
1989 wret = push_node_left(trans, fs_info, left, mid, 1);
1995 * then try to empty the right most buffer into the middle
1998 wret = push_node_left(trans, fs_info, mid, right, 1);
1999 if (wret < 0 && wret != -ENOSPC)
2001 if (btrfs_header_nritems(right) == 0) {
2002 clean_tree_block(fs_info, right);
2003 btrfs_tree_unlock(right);
2004 del_ptr(root, path, level + 1, pslot + 1);
2005 root_sub_used(root, right->len);
2006 btrfs_free_tree_block(trans, root, right, 0, 1);
2007 free_extent_buffer_stale(right);
2010 struct btrfs_disk_key right_key;
2011 btrfs_node_key(right, &right_key, 0);
2012 tree_mod_log_set_node_key(fs_info, parent,
2014 btrfs_set_node_key(parent, &right_key, pslot + 1);
2015 btrfs_mark_buffer_dirty(parent);
2018 if (btrfs_header_nritems(mid) == 1) {
2020 * we're not allowed to leave a node with one item in the
2021 * tree during a delete. A deletion from lower in the tree
2022 * could try to delete the only pointer in this node.
2023 * So, pull some keys from the left.
2024 * There has to be a left pointer at this point because
2025 * otherwise we would have pulled some pointers from the
2030 btrfs_handle_fs_error(fs_info, ret, NULL);
2033 wret = balance_node_right(trans, fs_info, mid, left);
2039 wret = push_node_left(trans, fs_info, left, mid, 1);
2045 if (btrfs_header_nritems(mid) == 0) {
2046 clean_tree_block(fs_info, mid);
2047 btrfs_tree_unlock(mid);
2048 del_ptr(root, path, level + 1, pslot);
2049 root_sub_used(root, mid->len);
2050 btrfs_free_tree_block(trans, root, mid, 0, 1);
2051 free_extent_buffer_stale(mid);
2054 /* update the parent key to reflect our changes */
2055 struct btrfs_disk_key mid_key;
2056 btrfs_node_key(mid, &mid_key, 0);
2057 tree_mod_log_set_node_key(fs_info, parent, pslot, 0);
2058 btrfs_set_node_key(parent, &mid_key, pslot);
2059 btrfs_mark_buffer_dirty(parent);
2062 /* update the path */
2064 if (btrfs_header_nritems(left) > orig_slot) {
2065 extent_buffer_get(left);
2066 /* left was locked after cow */
2067 path->nodes[level] = left;
2068 path->slots[level + 1] -= 1;
2069 path->slots[level] = orig_slot;
2071 btrfs_tree_unlock(mid);
2072 free_extent_buffer(mid);
2075 orig_slot -= btrfs_header_nritems(left);
2076 path->slots[level] = orig_slot;
2079 /* double check we haven't messed things up */
2081 btrfs_node_blockptr(path->nodes[level], path->slots[level]))
2085 btrfs_tree_unlock(right);
2086 free_extent_buffer(right);
2089 if (path->nodes[level] != left)
2090 btrfs_tree_unlock(left);
2091 free_extent_buffer(left);
2096 /* Node balancing for insertion. Here we only split or push nodes around
2097 * when they are completely full. This is also done top down, so we
2098 * have to be pessimistic.
2100 static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
2101 struct btrfs_root *root,
2102 struct btrfs_path *path, int level)
2104 struct btrfs_fs_info *fs_info = root->fs_info;
2105 struct extent_buffer *right = NULL;
2106 struct extent_buffer *mid;
2107 struct extent_buffer *left = NULL;
2108 struct extent_buffer *parent = NULL;
2112 int orig_slot = path->slots[level];
2117 mid = path->nodes[level];
2118 WARN_ON(btrfs_header_generation(mid) != trans->transid);
2120 if (level < BTRFS_MAX_LEVEL - 1) {
2121 parent = path->nodes[level + 1];
2122 pslot = path->slots[level + 1];
2128 left = read_node_slot(fs_info, parent, pslot - 1);
2132 /* first, try to make some room in the middle buffer */
2136 btrfs_tree_lock(left);
2137 btrfs_set_lock_blocking(left);
2139 left_nr = btrfs_header_nritems(left);
2140 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 1) {
2143 ret = btrfs_cow_block(trans, root, left, parent,
2148 wret = push_node_left(trans, fs_info,
2155 struct btrfs_disk_key disk_key;
2156 orig_slot += left_nr;
2157 btrfs_node_key(mid, &disk_key, 0);
2158 tree_mod_log_set_node_key(fs_info, parent, pslot, 0);
2159 btrfs_set_node_key(parent, &disk_key, pslot);
2160 btrfs_mark_buffer_dirty(parent);
2161 if (btrfs_header_nritems(left) > orig_slot) {
2162 path->nodes[level] = left;
2163 path->slots[level + 1] -= 1;
2164 path->slots[level] = orig_slot;
2165 btrfs_tree_unlock(mid);
2166 free_extent_buffer(mid);
2169 btrfs_header_nritems(left);
2170 path->slots[level] = orig_slot;
2171 btrfs_tree_unlock(left);
2172 free_extent_buffer(left);
2176 btrfs_tree_unlock(left);
2177 free_extent_buffer(left);
2179 right = read_node_slot(fs_info, parent, pslot + 1);
2184 * then try to empty the right most buffer into the middle
2189 btrfs_tree_lock(right);
2190 btrfs_set_lock_blocking(right);
2192 right_nr = btrfs_header_nritems(right);
2193 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 1) {
2196 ret = btrfs_cow_block(trans, root, right,
2202 wret = balance_node_right(trans, fs_info,
2209 struct btrfs_disk_key disk_key;
2211 btrfs_node_key(right, &disk_key, 0);
2212 tree_mod_log_set_node_key(fs_info, parent,
2214 btrfs_set_node_key(parent, &disk_key, pslot + 1);
2215 btrfs_mark_buffer_dirty(parent);
2217 if (btrfs_header_nritems(mid) <= orig_slot) {
2218 path->nodes[level] = right;
2219 path->slots[level + 1] += 1;
2220 path->slots[level] = orig_slot -
2221 btrfs_header_nritems(mid);
2222 btrfs_tree_unlock(mid);
2223 free_extent_buffer(mid);
2225 btrfs_tree_unlock(right);
2226 free_extent_buffer(right);
2230 btrfs_tree_unlock(right);
2231 free_extent_buffer(right);
2237 * readahead one full node of leaves, finding things that are close
2238 * to the block in 'slot', and triggering ra on them.
2240 static void reada_for_search(struct btrfs_fs_info *fs_info,
2241 struct btrfs_path *path,
2242 int level, int slot, u64 objectid)
2244 struct extent_buffer *node;
2245 struct btrfs_disk_key disk_key;
2250 struct extent_buffer *eb;
2258 if (!path->nodes[level])
2261 node = path->nodes[level];
2263 search = btrfs_node_blockptr(node, slot);
2264 blocksize = fs_info->nodesize;
2265 eb = find_extent_buffer(fs_info, search);
2267 free_extent_buffer(eb);
2273 nritems = btrfs_header_nritems(node);
2277 if (path->reada == READA_BACK) {
2281 } else if (path->reada == READA_FORWARD) {
2286 if (path->reada == READA_BACK && objectid) {
2287 btrfs_node_key(node, &disk_key, nr);
2288 if (btrfs_disk_key_objectid(&disk_key) != objectid)
2291 search = btrfs_node_blockptr(node, nr);
2292 if ((search <= target && target - search <= 65536) ||
2293 (search > target && search - target <= 65536)) {
2294 readahead_tree_block(fs_info, search);
2298 if ((nread > 65536 || nscan > 32))
2303 static noinline void reada_for_balance(struct btrfs_fs_info *fs_info,
2304 struct btrfs_path *path, int level)
2308 struct extent_buffer *parent;
2309 struct extent_buffer *eb;
2314 parent = path->nodes[level + 1];
2318 nritems = btrfs_header_nritems(parent);
2319 slot = path->slots[level + 1];
2322 block1 = btrfs_node_blockptr(parent, slot - 1);
2323 gen = btrfs_node_ptr_generation(parent, slot - 1);
2324 eb = find_extent_buffer(fs_info, block1);
2326 * if we get -eagain from btrfs_buffer_uptodate, we
2327 * don't want to return eagain here. That will loop
2330 if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0)
2332 free_extent_buffer(eb);
2334 if (slot + 1 < nritems) {
2335 block2 = btrfs_node_blockptr(parent, slot + 1);
2336 gen = btrfs_node_ptr_generation(parent, slot + 1);
2337 eb = find_extent_buffer(fs_info, block2);
2338 if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0)
2340 free_extent_buffer(eb);
2344 readahead_tree_block(fs_info, block1);
2346 readahead_tree_block(fs_info, block2);
2351 * when we walk down the tree, it is usually safe to unlock the higher layers
2352 * in the tree. The exceptions are when our path goes through slot 0, because
2353 * operations on the tree might require changing key pointers higher up in the
2356 * callers might also have set path->keep_locks, which tells this code to keep
2357 * the lock if the path points to the last slot in the block. This is part of
2358 * walking through the tree, and selecting the next slot in the higher block.
2360 * lowest_unlock sets the lowest level in the tree we're allowed to unlock. so
2361 * if lowest_unlock is 1, level 0 won't be unlocked
2363 static noinline void unlock_up(struct btrfs_path *path, int level,
2364 int lowest_unlock, int min_write_lock_level,
2365 int *write_lock_level)
2368 int skip_level = level;
2370 struct extent_buffer *t;
2372 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
2373 if (!path->nodes[i])
2375 if (!path->locks[i])
2377 if (!no_skips && path->slots[i] == 0) {
2381 if (!no_skips && path->keep_locks) {
2384 nritems = btrfs_header_nritems(t);
2385 if (nritems < 1 || path->slots[i] >= nritems - 1) {
2390 if (skip_level < i && i >= lowest_unlock)
2394 if (i >= lowest_unlock && i > skip_level && path->locks[i]) {
2395 btrfs_tree_unlock_rw(t, path->locks[i]);
2397 if (write_lock_level &&
2398 i > min_write_lock_level &&
2399 i <= *write_lock_level) {
2400 *write_lock_level = i - 1;
2407 * This releases any locks held in the path starting at level and
2408 * going all the way up to the root.
2410 * btrfs_search_slot will keep the lock held on higher nodes in a few
2411 * corner cases, such as COW of the block at slot zero in the node. This
2412 * ignores those rules, and it should only be called when there are no
2413 * more updates to be done higher up in the tree.
2415 noinline void btrfs_unlock_up_safe(struct btrfs_path *path, int level)
2419 if (path->keep_locks)
2422 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
2423 if (!path->nodes[i])
2425 if (!path->locks[i])
2427 btrfs_tree_unlock_rw(path->nodes[i], path->locks[i]);
2433 * helper function for btrfs_search_slot. The goal is to find a block
2434 * in cache without setting the path to blocking. If we find the block
2435 * we return zero and the path is unchanged.
2437 * If we can't find the block, we set the path blocking and do some
2438 * reada. -EAGAIN is returned and the search must be repeated.
2441 read_block_for_search(struct btrfs_root *root, struct btrfs_path *p,
2442 struct extent_buffer **eb_ret, int level, int slot,
2443 const struct btrfs_key *key)
2445 struct btrfs_fs_info *fs_info = root->fs_info;
2448 struct extent_buffer *b = *eb_ret;
2449 struct extent_buffer *tmp;
2452 blocknr = btrfs_node_blockptr(b, slot);
2453 gen = btrfs_node_ptr_generation(b, slot);
2455 tmp = find_extent_buffer(fs_info, blocknr);
2457 /* first we do an atomic uptodate check */
2458 if (btrfs_buffer_uptodate(tmp, gen, 1) > 0) {
2463 /* the pages were up to date, but we failed
2464 * the generation number check. Do a full
2465 * read for the generation number that is correct.
2466 * We must do this without dropping locks so
2467 * we can trust our generation number
2469 btrfs_set_path_blocking(p);
2471 /* now we're allowed to do a blocking uptodate check */
2472 ret = btrfs_read_buffer(tmp, gen);
2477 free_extent_buffer(tmp);
2478 btrfs_release_path(p);
2483 * reduce lock contention at high levels
2484 * of the btree by dropping locks before
2485 * we read. Don't release the lock on the current
2486 * level because we need to walk this node to figure
2487 * out which blocks to read.
2489 btrfs_unlock_up_safe(p, level + 1);
2490 btrfs_set_path_blocking(p);
2492 free_extent_buffer(tmp);
2493 if (p->reada != READA_NONE)
2494 reada_for_search(fs_info, p, level, slot, key->objectid);
2496 btrfs_release_path(p);
2499 tmp = read_tree_block(fs_info, blocknr, 0);
2502 * If the read above didn't mark this buffer up to date,
2503 * it will never end up being up to date. Set ret to EIO now
2504 * and give up so that our caller doesn't loop forever
2507 if (!btrfs_buffer_uptodate(tmp, 0, 0))
2509 free_extent_buffer(tmp);
2517 * helper function for btrfs_search_slot. This does all of the checks
2518 * for node-level blocks and does any balancing required based on
2521 * If no extra work was required, zero is returned. If we had to
2522 * drop the path, -EAGAIN is returned and btrfs_search_slot must
2526 setup_nodes_for_search(struct btrfs_trans_handle *trans,
2527 struct btrfs_root *root, struct btrfs_path *p,
2528 struct extent_buffer *b, int level, int ins_len,
2529 int *write_lock_level)
2531 struct btrfs_fs_info *fs_info = root->fs_info;
2534 if ((p->search_for_split || ins_len > 0) && btrfs_header_nritems(b) >=
2535 BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 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(fs_info, 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(fs_info) / 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(fs_info, 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 const 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, const 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 *root,
2672 const struct btrfs_key *key, struct btrfs_path *p,
2673 int ins_len, int cow)
2675 struct btrfs_fs_info *fs_info = root->fs_info;
2676 struct extent_buffer *b;
2681 int lowest_unlock = 1;
2683 /* everything at write_lock_level or lower must be write locked */
2684 int write_lock_level = 0;
2685 u8 lowest_level = 0;
2686 int min_write_lock_level;
2689 lowest_level = p->lowest_level;
2690 WARN_ON(lowest_level && ins_len > 0);
2691 WARN_ON(p->nodes[0] != NULL);
2692 BUG_ON(!cow && ins_len);
2697 /* when we are removing items, we might have to go up to level
2698 * two as we update tree pointers Make sure we keep write
2699 * for those levels as well
2701 write_lock_level = 2;
2702 } else if (ins_len > 0) {
2704 * for inserting items, make sure we have a write lock on
2705 * level 1 so we can update keys
2707 write_lock_level = 1;
2711 write_lock_level = -1;
2713 if (cow && (p->keep_locks || p->lowest_level))
2714 write_lock_level = BTRFS_MAX_LEVEL;
2716 min_write_lock_level = write_lock_level;
2721 * we try very hard to do read locks on the root
2723 root_lock = BTRFS_READ_LOCK;
2725 if (p->search_commit_root) {
2727 * the commit roots are read only
2728 * so we always do read locks
2730 if (p->need_commit_sem)
2731 down_read(&fs_info->commit_root_sem);
2732 b = root->commit_root;
2733 extent_buffer_get(b);
2734 level = btrfs_header_level(b);
2735 if (p->need_commit_sem)
2736 up_read(&fs_info->commit_root_sem);
2737 if (!p->skip_locking)
2738 btrfs_tree_read_lock(b);
2740 if (p->skip_locking) {
2741 b = btrfs_root_node(root);
2742 level = btrfs_header_level(b);
2744 /* we don't know the level of the root node
2745 * until we actually have it read locked
2747 b = btrfs_read_lock_root_node(root);
2748 level = btrfs_header_level(b);
2749 if (level <= write_lock_level) {
2750 /* whoops, must trade for write lock */
2751 btrfs_tree_read_unlock(b);
2752 free_extent_buffer(b);
2753 b = btrfs_lock_root_node(root);
2754 root_lock = BTRFS_WRITE_LOCK;
2756 /* the level might have changed, check again */
2757 level = btrfs_header_level(b);
2761 p->nodes[level] = b;
2762 if (!p->skip_locking)
2763 p->locks[level] = root_lock;
2766 level = btrfs_header_level(b);
2769 * setup the path here so we can release it under lock
2770 * contention with the cow code
2774 * if we don't really need to cow this block
2775 * then we don't want to set the path blocking,
2776 * so we test it here
2778 if (!should_cow_block(trans, root, b)) {
2779 trans->dirty = true;
2784 * must have write locks on this node and the
2787 if (level > write_lock_level ||
2788 (level + 1 > write_lock_level &&
2789 level + 1 < BTRFS_MAX_LEVEL &&
2790 p->nodes[level + 1])) {
2791 write_lock_level = level + 1;
2792 btrfs_release_path(p);
2796 btrfs_set_path_blocking(p);
2797 err = btrfs_cow_block(trans, root, b,
2798 p->nodes[level + 1],
2799 p->slots[level + 1], &b);
2806 p->nodes[level] = b;
2807 btrfs_clear_path_blocking(p, NULL, 0);
2810 * we have a lock on b and as long as we aren't changing
2811 * the tree, there is no way to for the items in b to change.
2812 * It is safe to drop the lock on our parent before we
2813 * go through the expensive btree search on b.
2815 * If we're inserting or deleting (ins_len != 0), then we might
2816 * be changing slot zero, which may require changing the parent.
2817 * So, we can't drop the lock until after we know which slot
2818 * we're operating on.
2820 if (!ins_len && !p->keep_locks) {
2823 if (u < BTRFS_MAX_LEVEL && p->locks[u]) {
2824 btrfs_tree_unlock_rw(p->nodes[u], p->locks[u]);
2829 ret = key_search(b, key, level, &prev_cmp, &slot);
2835 if (ret && slot > 0) {
2839 p->slots[level] = slot;
2840 err = setup_nodes_for_search(trans, root, p, b, level,
2841 ins_len, &write_lock_level);
2848 b = p->nodes[level];
2849 slot = p->slots[level];
2852 * slot 0 is special, if we change the key
2853 * we have to update the parent pointer
2854 * which means we must have a write lock
2857 if (slot == 0 && ins_len &&
2858 write_lock_level < level + 1) {
2859 write_lock_level = level + 1;
2860 btrfs_release_path(p);
2864 unlock_up(p, level, lowest_unlock,
2865 min_write_lock_level, &write_lock_level);
2867 if (level == lowest_level) {
2873 err = read_block_for_search(root, p, &b, level,
2882 if (!p->skip_locking) {
2883 level = btrfs_header_level(b);
2884 if (level <= write_lock_level) {
2885 err = btrfs_try_tree_write_lock(b);
2887 btrfs_set_path_blocking(p);
2889 btrfs_clear_path_blocking(p, b,
2892 p->locks[level] = BTRFS_WRITE_LOCK;
2894 err = btrfs_tree_read_lock_atomic(b);
2896 btrfs_set_path_blocking(p);
2897 btrfs_tree_read_lock(b);
2898 btrfs_clear_path_blocking(p, b,
2901 p->locks[level] = BTRFS_READ_LOCK;
2903 p->nodes[level] = b;
2906 p->slots[level] = slot;
2908 btrfs_leaf_free_space(fs_info, b) < ins_len) {
2909 if (write_lock_level < 1) {
2910 write_lock_level = 1;
2911 btrfs_release_path(p);
2915 btrfs_set_path_blocking(p);
2916 err = split_leaf(trans, root, key,
2917 p, ins_len, ret == 0);
2918 btrfs_clear_path_blocking(p, NULL, 0);
2926 if (!p->search_for_split)
2927 unlock_up(p, level, lowest_unlock,
2928 min_write_lock_level, &write_lock_level);
2935 * we don't really know what they plan on doing with the path
2936 * from here on, so for now just mark it as blocking
2938 if (!p->leave_spinning)
2939 btrfs_set_path_blocking(p);
2940 if (ret < 0 && !p->skip_release_on_error)
2941 btrfs_release_path(p);
2946 * Like btrfs_search_slot, this looks for a key in the given tree. It uses the
2947 * current state of the tree together with the operations recorded in the tree
2948 * modification log to search for the key in a previous version of this tree, as
2949 * denoted by the time_seq parameter.
2951 * Naturally, there is no support for insert, delete or cow operations.
2953 * The resulting path and return value will be set up as if we called
2954 * btrfs_search_slot at that point in time with ins_len and cow both set to 0.
2956 int btrfs_search_old_slot(struct btrfs_root *root, const struct btrfs_key *key,
2957 struct btrfs_path *p, u64 time_seq)
2959 struct btrfs_fs_info *fs_info = root->fs_info;
2960 struct extent_buffer *b;
2965 int lowest_unlock = 1;
2966 u8 lowest_level = 0;
2969 lowest_level = p->lowest_level;
2970 WARN_ON(p->nodes[0] != NULL);
2972 if (p->search_commit_root) {
2974 return btrfs_search_slot(NULL, root, key, p, 0, 0);
2978 b = get_old_root(root, time_seq);
2979 level = btrfs_header_level(b);
2980 p->locks[level] = BTRFS_READ_LOCK;
2983 level = btrfs_header_level(b);
2984 p->nodes[level] = b;
2985 btrfs_clear_path_blocking(p, NULL, 0);
2988 * we have a lock on b and as long as we aren't changing
2989 * the tree, there is no way to for the items in b to change.
2990 * It is safe to drop the lock on our parent before we
2991 * go through the expensive btree search on b.
2993 btrfs_unlock_up_safe(p, level + 1);
2996 * Since we can unwind ebs we want to do a real search every
3000 ret = key_search(b, key, level, &prev_cmp, &slot);
3004 if (ret && slot > 0) {
3008 p->slots[level] = slot;
3009 unlock_up(p, level, lowest_unlock, 0, NULL);
3011 if (level == lowest_level) {
3017 err = read_block_for_search(root, p, &b, level,
3026 level = btrfs_header_level(b);
3027 err = btrfs_tree_read_lock_atomic(b);
3029 btrfs_set_path_blocking(p);
3030 btrfs_tree_read_lock(b);
3031 btrfs_clear_path_blocking(p, b,
3034 b = tree_mod_log_rewind(fs_info, p, b, time_seq);
3039 p->locks[level] = BTRFS_READ_LOCK;
3040 p->nodes[level] = b;
3042 p->slots[level] = slot;
3043 unlock_up(p, level, lowest_unlock, 0, NULL);
3049 if (!p->leave_spinning)
3050 btrfs_set_path_blocking(p);
3052 btrfs_release_path(p);
3058 * helper to use instead of search slot if no exact match is needed but
3059 * instead the next or previous item should be returned.
3060 * When find_higher is true, the next higher item is returned, the next lower
3062 * When return_any and find_higher are both true, and no higher item is found,
3063 * return the next lower instead.
3064 * When return_any is true and find_higher is false, and no lower item is found,
3065 * return the next higher instead.
3066 * It returns 0 if any item is found, 1 if none is found (tree empty), and
3069 int btrfs_search_slot_for_read(struct btrfs_root *root,
3070 const struct btrfs_key *key,
3071 struct btrfs_path *p, int find_higher,
3075 struct extent_buffer *leaf;
3078 ret = btrfs_search_slot(NULL, root, key, p, 0, 0);
3082 * a return value of 1 means the path is at the position where the
3083 * item should be inserted. Normally this is the next bigger item,
3084 * but in case the previous item is the last in a leaf, path points
3085 * to the first free slot in the previous leaf, i.e. at an invalid
3091 if (p->slots[0] >= btrfs_header_nritems(leaf)) {
3092 ret = btrfs_next_leaf(root, p);
3098 * no higher item found, return the next
3103 btrfs_release_path(p);
3107 if (p->slots[0] == 0) {
3108 ret = btrfs_prev_leaf(root, p);
3113 if (p->slots[0] == btrfs_header_nritems(leaf))
3120 * no lower item found, return the next
3125 btrfs_release_path(p);
3135 * adjust the pointers going up the tree, starting at level
3136 * making sure the right key of each node is points to 'key'.
3137 * This is used after shifting pointers to the left, so it stops
3138 * fixing up pointers when a given leaf/node is not in slot 0 of the
3142 static void fixup_low_keys(struct btrfs_fs_info *fs_info,
3143 struct btrfs_path *path,
3144 struct btrfs_disk_key *key, int level)
3147 struct extent_buffer *t;
3149 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
3150 int tslot = path->slots[i];
3151 if (!path->nodes[i])
3154 tree_mod_log_set_node_key(fs_info, t, tslot, 1);
3155 btrfs_set_node_key(t, key, tslot);
3156 btrfs_mark_buffer_dirty(path->nodes[i]);
3165 * This function isn't completely safe. It's the caller's responsibility
3166 * that the new key won't break the order
3168 void btrfs_set_item_key_safe(struct btrfs_fs_info *fs_info,
3169 struct btrfs_path *path,
3170 const struct btrfs_key *new_key)
3172 struct btrfs_disk_key disk_key;
3173 struct extent_buffer *eb;
3176 eb = path->nodes[0];
3177 slot = path->slots[0];
3179 btrfs_item_key(eb, &disk_key, slot - 1);
3180 BUG_ON(comp_keys(&disk_key, new_key) >= 0);
3182 if (slot < btrfs_header_nritems(eb) - 1) {
3183 btrfs_item_key(eb, &disk_key, slot + 1);
3184 BUG_ON(comp_keys(&disk_key, new_key) <= 0);
3187 btrfs_cpu_key_to_disk(&disk_key, new_key);
3188 btrfs_set_item_key(eb, &disk_key, slot);
3189 btrfs_mark_buffer_dirty(eb);
3191 fixup_low_keys(fs_info, path, &disk_key, 1);
3195 * try to push data from one node into the next node left in the
3198 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
3199 * error, and > 0 if there was no room in the left hand block.
3201 static int push_node_left(struct btrfs_trans_handle *trans,
3202 struct btrfs_fs_info *fs_info,
3203 struct extent_buffer *dst,
3204 struct extent_buffer *src, int empty)
3211 src_nritems = btrfs_header_nritems(src);
3212 dst_nritems = btrfs_header_nritems(dst);
3213 push_items = BTRFS_NODEPTRS_PER_BLOCK(fs_info) - dst_nritems;
3214 WARN_ON(btrfs_header_generation(src) != trans->transid);
3215 WARN_ON(btrfs_header_generation(dst) != trans->transid);
3217 if (!empty && src_nritems <= 8)
3220 if (push_items <= 0)
3224 push_items = min(src_nritems, push_items);
3225 if (push_items < src_nritems) {
3226 /* leave at least 8 pointers in the node if
3227 * we aren't going to empty it
3229 if (src_nritems - push_items < 8) {
3230 if (push_items <= 8)
3236 push_items = min(src_nritems - 8, push_items);
3238 ret = tree_mod_log_eb_copy(fs_info, dst, src, dst_nritems, 0,
3241 btrfs_abort_transaction(trans, ret);
3244 copy_extent_buffer(dst, src,
3245 btrfs_node_key_ptr_offset(dst_nritems),
3246 btrfs_node_key_ptr_offset(0),
3247 push_items * sizeof(struct btrfs_key_ptr));
3249 if (push_items < src_nritems) {
3251 * don't call tree_mod_log_eb_move here, key removal was already
3252 * fully logged by tree_mod_log_eb_copy above.
3254 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
3255 btrfs_node_key_ptr_offset(push_items),
3256 (src_nritems - push_items) *
3257 sizeof(struct btrfs_key_ptr));
3259 btrfs_set_header_nritems(src, src_nritems - push_items);
3260 btrfs_set_header_nritems(dst, dst_nritems + push_items);
3261 btrfs_mark_buffer_dirty(src);
3262 btrfs_mark_buffer_dirty(dst);
3268 * try to push data from one node into the next node right in the
3271 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
3272 * error, and > 0 if there was no room in the right hand block.
3274 * this will only push up to 1/2 the contents of the left node over
3276 static int balance_node_right(struct btrfs_trans_handle *trans,
3277 struct btrfs_fs_info *fs_info,
3278 struct extent_buffer *dst,
3279 struct extent_buffer *src)
3287 WARN_ON(btrfs_header_generation(src) != trans->transid);
3288 WARN_ON(btrfs_header_generation(dst) != trans->transid);
3290 src_nritems = btrfs_header_nritems(src);
3291 dst_nritems = btrfs_header_nritems(dst);
3292 push_items = BTRFS_NODEPTRS_PER_BLOCK(fs_info) - dst_nritems;
3293 if (push_items <= 0)
3296 if (src_nritems < 4)
3299 max_push = src_nritems / 2 + 1;
3300 /* don't try to empty the node */
3301 if (max_push >= src_nritems)
3304 if (max_push < push_items)
3305 push_items = max_push;
3307 tree_mod_log_eb_move(fs_info, dst, push_items, 0, dst_nritems);
3308 memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
3309 btrfs_node_key_ptr_offset(0),
3311 sizeof(struct btrfs_key_ptr));
3313 ret = tree_mod_log_eb_copy(fs_info, dst, src, 0,
3314 src_nritems - push_items, push_items);
3316 btrfs_abort_transaction(trans, ret);
3319 copy_extent_buffer(dst, src,
3320 btrfs_node_key_ptr_offset(0),
3321 btrfs_node_key_ptr_offset(src_nritems - push_items),
3322 push_items * sizeof(struct btrfs_key_ptr));
3324 btrfs_set_header_nritems(src, src_nritems - push_items);
3325 btrfs_set_header_nritems(dst, dst_nritems + push_items);
3327 btrfs_mark_buffer_dirty(src);
3328 btrfs_mark_buffer_dirty(dst);
3334 * helper function to insert a new root level in the tree.
3335 * A new node is allocated, and a single item is inserted to
3336 * point to the existing root
3338 * returns zero on success or < 0 on failure.
3340 static noinline int insert_new_root(struct btrfs_trans_handle *trans,
3341 struct btrfs_root *root,
3342 struct btrfs_path *path, int level)
3344 struct btrfs_fs_info *fs_info = root->fs_info;
3346 struct extent_buffer *lower;
3347 struct extent_buffer *c;
3348 struct extent_buffer *old;
3349 struct btrfs_disk_key lower_key;
3351 BUG_ON(path->nodes[level]);
3352 BUG_ON(path->nodes[level-1] != root->node);
3354 lower = path->nodes[level-1];
3356 btrfs_item_key(lower, &lower_key, 0);
3358 btrfs_node_key(lower, &lower_key, 0);
3360 c = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid,
3361 &lower_key, level, root->node->start, 0);
3365 root_add_used(root, fs_info->nodesize);
3367 memzero_extent_buffer(c, 0, sizeof(struct btrfs_header));
3368 btrfs_set_header_nritems(c, 1);
3369 btrfs_set_header_level(c, level);
3370 btrfs_set_header_bytenr(c, c->start);
3371 btrfs_set_header_generation(c, trans->transid);
3372 btrfs_set_header_backref_rev(c, BTRFS_MIXED_BACKREF_REV);
3373 btrfs_set_header_owner(c, root->root_key.objectid);
3375 write_extent_buffer_fsid(c, fs_info->fsid);
3376 write_extent_buffer_chunk_tree_uuid(c, fs_info->chunk_tree_uuid);
3378 btrfs_set_node_key(c, &lower_key, 0);
3379 btrfs_set_node_blockptr(c, 0, lower->start);
3380 lower_gen = btrfs_header_generation(lower);
3381 WARN_ON(lower_gen != trans->transid);
3383 btrfs_set_node_ptr_generation(c, 0, lower_gen);
3385 btrfs_mark_buffer_dirty(c);
3388 tree_mod_log_set_root_pointer(root, c, 0);
3389 rcu_assign_pointer(root->node, c);
3391 /* the super has an extra ref to root->node */
3392 free_extent_buffer(old);
3394 add_root_to_dirty_list(root);
3395 extent_buffer_get(c);
3396 path->nodes[level] = c;
3397 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
3398 path->slots[level] = 0;
3403 * worker function to insert a single pointer in a node.
3404 * the node should have enough room for the pointer already
3406 * slot and level indicate where you want the key to go, and
3407 * blocknr is the block the key points to.
3409 static void insert_ptr(struct btrfs_trans_handle *trans,
3410 struct btrfs_fs_info *fs_info, struct btrfs_path *path,
3411 struct btrfs_disk_key *key, u64 bytenr,
3412 int slot, int level)
3414 struct extent_buffer *lower;
3418 BUG_ON(!path->nodes[level]);
3419 btrfs_assert_tree_locked(path->nodes[level]);
3420 lower = path->nodes[level];
3421 nritems = btrfs_header_nritems(lower);
3422 BUG_ON(slot > nritems);
3423 BUG_ON(nritems == BTRFS_NODEPTRS_PER_BLOCK(fs_info));
3424 if (slot != nritems) {
3426 tree_mod_log_eb_move(fs_info, lower, slot + 1,
3427 slot, nritems - slot);
3428 memmove_extent_buffer(lower,
3429 btrfs_node_key_ptr_offset(slot + 1),
3430 btrfs_node_key_ptr_offset(slot),
3431 (nritems - slot) * sizeof(struct btrfs_key_ptr));
3434 ret = tree_mod_log_insert_key(fs_info, lower, slot,
3435 MOD_LOG_KEY_ADD, GFP_NOFS);
3438 btrfs_set_node_key(lower, key, slot);
3439 btrfs_set_node_blockptr(lower, slot, bytenr);
3440 WARN_ON(trans->transid == 0);
3441 btrfs_set_node_ptr_generation(lower, slot, trans->transid);
3442 btrfs_set_header_nritems(lower, nritems + 1);
3443 btrfs_mark_buffer_dirty(lower);
3447 * split the node at the specified level in path in two.
3448 * The path is corrected to point to the appropriate node after the split
3450 * Before splitting this tries to make some room in the node by pushing
3451 * left and right, if either one works, it returns right away.
3453 * returns 0 on success and < 0 on failure
3455 static noinline int split_node(struct btrfs_trans_handle *trans,
3456 struct btrfs_root *root,
3457 struct btrfs_path *path, int level)
3459 struct btrfs_fs_info *fs_info = root->fs_info;
3460 struct extent_buffer *c;
3461 struct extent_buffer *split;
3462 struct btrfs_disk_key disk_key;
3467 c = path->nodes[level];
3468 WARN_ON(btrfs_header_generation(c) != trans->transid);
3469 if (c == root->node) {
3471 * trying to split the root, lets make a new one
3473 * tree mod log: We don't log_removal old root in
3474 * insert_new_root, because that root buffer will be kept as a
3475 * normal node. We are going to log removal of half of the
3476 * elements below with tree_mod_log_eb_copy. We're holding a
3477 * tree lock on the buffer, which is why we cannot race with
3478 * other tree_mod_log users.
3480 ret = insert_new_root(trans, root, path, level + 1);
3484 ret = push_nodes_for_insert(trans, root, path, level);
3485 c = path->nodes[level];
3486 if (!ret && btrfs_header_nritems(c) <
3487 BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 3)
3493 c_nritems = btrfs_header_nritems(c);
3494 mid = (c_nritems + 1) / 2;
3495 btrfs_node_key(c, &disk_key, mid);
3497 split = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid,
3498 &disk_key, level, c->start, 0);
3500 return PTR_ERR(split);
3502 root_add_used(root, fs_info->nodesize);
3504 memzero_extent_buffer(split, 0, sizeof(struct btrfs_header));
3505 btrfs_set_header_level(split, btrfs_header_level(c));
3506 btrfs_set_header_bytenr(split, split->start);
3507 btrfs_set_header_generation(split, trans->transid);
3508 btrfs_set_header_backref_rev(split, BTRFS_MIXED_BACKREF_REV);
3509 btrfs_set_header_owner(split, root->root_key.objectid);
3510 write_extent_buffer_fsid(split, fs_info->fsid);
3511 write_extent_buffer_chunk_tree_uuid(split, fs_info->chunk_tree_uuid);
3513 ret = tree_mod_log_eb_copy(fs_info, split, c, 0, mid, c_nritems - mid);
3515 btrfs_abort_transaction(trans, ret);
3518 copy_extent_buffer(split, c,
3519 btrfs_node_key_ptr_offset(0),
3520 btrfs_node_key_ptr_offset(mid),
3521 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
3522 btrfs_set_header_nritems(split, c_nritems - mid);
3523 btrfs_set_header_nritems(c, mid);
3526 btrfs_mark_buffer_dirty(c);
3527 btrfs_mark_buffer_dirty(split);
3529 insert_ptr(trans, fs_info, path, &disk_key, split->start,
3530 path->slots[level + 1] + 1, level + 1);
3532 if (path->slots[level] >= mid) {
3533 path->slots[level] -= mid;
3534 btrfs_tree_unlock(c);
3535 free_extent_buffer(c);
3536 path->nodes[level] = split;
3537 path->slots[level + 1] += 1;
3539 btrfs_tree_unlock(split);
3540 free_extent_buffer(split);
3546 * how many bytes are required to store the items in a leaf. start
3547 * and nr indicate which items in the leaf to check. This totals up the
3548 * space used both by the item structs and the item data
3550 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
3552 struct btrfs_item *start_item;
3553 struct btrfs_item *end_item;
3554 struct btrfs_map_token token;
3556 int nritems = btrfs_header_nritems(l);
3557 int end = min(nritems, start + nr) - 1;
3561 btrfs_init_map_token(&token);
3562 start_item = btrfs_item_nr(start);
3563 end_item = btrfs_item_nr(end);
3564 data_len = btrfs_token_item_offset(l, start_item, &token) +
3565 btrfs_token_item_size(l, start_item, &token);
3566 data_len = data_len - btrfs_token_item_offset(l, end_item, &token);
3567 data_len += sizeof(struct btrfs_item) * nr;
3568 WARN_ON(data_len < 0);
3573 * The space between the end of the leaf items and
3574 * the start of the leaf data. IOW, how much room
3575 * the leaf has left for both items and data
3577 noinline int btrfs_leaf_free_space(struct btrfs_fs_info *fs_info,
3578 struct extent_buffer *leaf)
3580 int nritems = btrfs_header_nritems(leaf);
3583 ret = BTRFS_LEAF_DATA_SIZE(fs_info) - leaf_space_used(leaf, 0, nritems);
3586 "leaf free space ret %d, leaf data size %lu, used %d nritems %d",
3588 (unsigned long) BTRFS_LEAF_DATA_SIZE(fs_info),
3589 leaf_space_used(leaf, 0, nritems), nritems);
3595 * min slot controls the lowest index we're willing to push to the
3596 * right. We'll push up to and including min_slot, but no lower
3598 static noinline int __push_leaf_right(struct btrfs_fs_info *fs_info,
3599 struct btrfs_path *path,
3600 int data_size, int empty,
3601 struct extent_buffer *right,
3602 int free_space, u32 left_nritems,
3605 struct extent_buffer *left = path->nodes[0];
3606 struct extent_buffer *upper = path->nodes[1];
3607 struct btrfs_map_token token;
3608 struct btrfs_disk_key disk_key;
3613 struct btrfs_item *item;
3619 btrfs_init_map_token(&token);
3624 nr = max_t(u32, 1, min_slot);
3626 if (path->slots[0] >= left_nritems)
3627 push_space += data_size;
3629 slot = path->slots[1];
3630 i = left_nritems - 1;
3632 item = btrfs_item_nr(i);
3634 if (!empty && push_items > 0) {
3635 if (path->slots[0] > i)
3637 if (path->slots[0] == i) {
3638 int space = btrfs_leaf_free_space(fs_info, left);
3639 if (space + push_space * 2 > free_space)
3644 if (path->slots[0] == i)
3645 push_space += data_size;
3647 this_item_size = btrfs_item_size(left, item);
3648 if (this_item_size + sizeof(*item) + push_space > free_space)
3652 push_space += this_item_size + sizeof(*item);
3658 if (push_items == 0)
3661 WARN_ON(!empty && push_items == left_nritems);
3663 /* push left to right */
3664 right_nritems = btrfs_header_nritems(right);
3666 push_space = btrfs_item_end_nr(left, left_nritems - push_items);
3667 push_space -= leaf_data_end(fs_info, left);
3669 /* make room in the right data area */
3670 data_end = leaf_data_end(fs_info, right);
3671 memmove_extent_buffer(right,
3672 btrfs_leaf_data(right) + data_end - push_space,
3673 btrfs_leaf_data(right) + data_end,
3674 BTRFS_LEAF_DATA_SIZE(fs_info) - data_end);
3676 /* copy from the left data area */
3677 copy_extent_buffer(right, left, btrfs_leaf_data(right) +
3678 BTRFS_LEAF_DATA_SIZE(fs_info) - push_space,
3679 btrfs_leaf_data(left) + leaf_data_end(fs_info, left),
3682 memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
3683 btrfs_item_nr_offset(0),
3684 right_nritems * sizeof(struct btrfs_item));
3686 /* copy the items from left to right */
3687 copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
3688 btrfs_item_nr_offset(left_nritems - push_items),
3689 push_items * sizeof(struct btrfs_item));
3691 /* update the item pointers */
3692 right_nritems += push_items;
3693 btrfs_set_header_nritems(right, right_nritems);
3694 push_space = BTRFS_LEAF_DATA_SIZE(fs_info);
3695 for (i = 0; i < right_nritems; i++) {
3696 item = btrfs_item_nr(i);
3697 push_space -= btrfs_token_item_size(right, item, &token);
3698 btrfs_set_token_item_offset(right, item, push_space, &token);
3701 left_nritems -= push_items;
3702 btrfs_set_header_nritems(left, left_nritems);
3705 btrfs_mark_buffer_dirty(left);
3707 clean_tree_block(fs_info, left);
3709 btrfs_mark_buffer_dirty(right);
3711 btrfs_item_key(right, &disk_key, 0);
3712 btrfs_set_node_key(upper, &disk_key, slot + 1);
3713 btrfs_mark_buffer_dirty(upper);
3715 /* then fixup the leaf pointer in the path */
3716 if (path->slots[0] >= left_nritems) {
3717 path->slots[0] -= left_nritems;
3718 if (btrfs_header_nritems(path->nodes[0]) == 0)
3719 clean_tree_block(fs_info, path->nodes[0]);
3720 btrfs_tree_unlock(path->nodes[0]);
3721 free_extent_buffer(path->nodes[0]);
3722 path->nodes[0] = right;
3723 path->slots[1] += 1;
3725 btrfs_tree_unlock(right);
3726 free_extent_buffer(right);
3731 btrfs_tree_unlock(right);
3732 free_extent_buffer(right);
3737 * push some data in the path leaf to the right, trying to free up at
3738 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3740 * returns 1 if the push failed because the other node didn't have enough
3741 * room, 0 if everything worked out and < 0 if there were major errors.
3743 * this will push starting from min_slot to the end of the leaf. It won't
3744 * push any slot lower than min_slot
3746 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
3747 *root, struct btrfs_path *path,
3748 int min_data_size, int data_size,
3749 int empty, u32 min_slot)
3751 struct btrfs_fs_info *fs_info = root->fs_info;
3752 struct extent_buffer *left = path->nodes[0];
3753 struct extent_buffer *right;
3754 struct extent_buffer *upper;
3760 if (!path->nodes[1])
3763 slot = path->slots[1];
3764 upper = path->nodes[1];
3765 if (slot >= btrfs_header_nritems(upper) - 1)
3768 btrfs_assert_tree_locked(path->nodes[1]);
3770 right = read_node_slot(fs_info, upper, slot + 1);
3772 * slot + 1 is not valid or we fail to read the right node,
3773 * no big deal, just return.
3778 btrfs_tree_lock(right);
3779 btrfs_set_lock_blocking(right);
3781 free_space = btrfs_leaf_free_space(fs_info, right);
3782 if (free_space < data_size)
3785 /* cow and double check */
3786 ret = btrfs_cow_block(trans, root, right, upper,
3791 free_space = btrfs_leaf_free_space(fs_info, right);
3792 if (free_space < data_size)
3795 left_nritems = btrfs_header_nritems(left);
3796 if (left_nritems == 0)
3799 if (path->slots[0] == left_nritems && !empty) {
3800 /* Key greater than all keys in the leaf, right neighbor has
3801 * enough room for it and we're not emptying our leaf to delete
3802 * it, therefore use right neighbor to insert the new item and
3803 * no need to touch/dirty our left leaft. */
3804 btrfs_tree_unlock(left);
3805 free_extent_buffer(left);
3806 path->nodes[0] = right;
3812 return __push_leaf_right(fs_info, path, min_data_size, empty,
3813 right, free_space, left_nritems, min_slot);
3815 btrfs_tree_unlock(right);
3816 free_extent_buffer(right);
3821 * push some data in the path leaf to the left, trying to free up at
3822 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3824 * max_slot can put a limit on how far into the leaf we'll push items. The
3825 * item at 'max_slot' won't be touched. Use (u32)-1 to make us do all the
3828 static noinline int __push_leaf_left(struct btrfs_fs_info *fs_info,
3829 struct btrfs_path *path, int data_size,
3830 int empty, struct extent_buffer *left,
3831 int free_space, u32 right_nritems,
3834 struct btrfs_disk_key disk_key;
3835 struct extent_buffer *right = path->nodes[0];
3839 struct btrfs_item *item;
3840 u32 old_left_nritems;
3844 u32 old_left_item_size;
3845 struct btrfs_map_token token;
3847 btrfs_init_map_token(&token);
3850 nr = min(right_nritems, max_slot);
3852 nr = min(right_nritems - 1, max_slot);
3854 for (i = 0; i < nr; i++) {
3855 item = btrfs_item_nr(i);
3857 if (!empty && push_items > 0) {
3858 if (path->slots[0] < i)
3860 if (path->slots[0] == i) {
3861 int space = btrfs_leaf_free_space(fs_info, right);
3862 if (space + push_space * 2 > free_space)
3867 if (path->slots[0] == i)
3868 push_space += data_size;
3870 this_item_size = btrfs_item_size(right, item);
3871 if (this_item_size + sizeof(*item) + push_space > free_space)
3875 push_space += this_item_size + sizeof(*item);
3878 if (push_items == 0) {
3882 WARN_ON(!empty && push_items == btrfs_header_nritems(right));
3884 /* push data from right to left */
3885 copy_extent_buffer(left, right,
3886 btrfs_item_nr_offset(btrfs_header_nritems(left)),
3887 btrfs_item_nr_offset(0),
3888 push_items * sizeof(struct btrfs_item));
3890 push_space = BTRFS_LEAF_DATA_SIZE(fs_info) -
3891 btrfs_item_offset_nr(right, push_items - 1);
3893 copy_extent_buffer(left, right, btrfs_leaf_data(left) +
3894 leaf_data_end(fs_info, left) - push_space,
3895 btrfs_leaf_data(right) +
3896 btrfs_item_offset_nr(right, push_items - 1),
3898 old_left_nritems = btrfs_header_nritems(left);
3899 BUG_ON(old_left_nritems <= 0);
3901 old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
3902 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
3905 item = btrfs_item_nr(i);
3907 ioff = btrfs_token_item_offset(left, item, &token);
3908 btrfs_set_token_item_offset(left, item,
3909 ioff - (BTRFS_LEAF_DATA_SIZE(fs_info) - old_left_item_size),
3912 btrfs_set_header_nritems(left, old_left_nritems + push_items);
3914 /* fixup right node */
3915 if (push_items > right_nritems)
3916 WARN(1, KERN_CRIT "push items %d nr %u\n", push_items,
3919 if (push_items < right_nritems) {
3920 push_space = btrfs_item_offset_nr(right, push_items - 1) -
3921 leaf_data_end(fs_info, right);
3922 memmove_extent_buffer(right, btrfs_leaf_data(right) +
3923 BTRFS_LEAF_DATA_SIZE(fs_info) - push_space,
3924 btrfs_leaf_data(right) +
3925 leaf_data_end(fs_info, right), push_space);
3927 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
3928 btrfs_item_nr_offset(push_items),
3929 (btrfs_header_nritems(right) - push_items) *
3930 sizeof(struct btrfs_item));
3932 right_nritems -= push_items;
3933 btrfs_set_header_nritems(right, right_nritems);
3934 push_space = BTRFS_LEAF_DATA_SIZE(fs_info);
3935 for (i = 0; i < right_nritems; i++) {
3936 item = btrfs_item_nr(i);
3938 push_space = push_space - btrfs_token_item_size(right,
3940 btrfs_set_token_item_offset(right, item, push_space, &token);
3943 btrfs_mark_buffer_dirty(left);
3945 btrfs_mark_buffer_dirty(right);
3947 clean_tree_block(fs_info, right);
3949 btrfs_item_key(right, &disk_key, 0);
3950 fixup_low_keys(fs_info, path, &disk_key, 1);
3952 /* then fixup the leaf pointer in the path */
3953 if (path->slots[0] < push_items) {
3954 path->slots[0] += old_left_nritems;
3955 btrfs_tree_unlock(path->nodes[0]);
3956 free_extent_buffer(path->nodes[0]);
3957 path->nodes[0] = left;
3958 path->slots[1] -= 1;
3960 btrfs_tree_unlock(left);
3961 free_extent_buffer(left);
3962 path->slots[0] -= push_items;
3964 BUG_ON(path->slots[0] < 0);
3967 btrfs_tree_unlock(left);
3968 free_extent_buffer(left);
3973 * push some data in the path leaf to the left, trying to free up at
3974 * least data_size bytes. returns zero if the push worked, nonzero otherwise
3976 * max_slot can put a limit on how far into the leaf we'll push items. The
3977 * item at 'max_slot' won't be touched. Use (u32)-1 to make us push all the
3980 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
3981 *root, struct btrfs_path *path, int min_data_size,
3982 int data_size, int empty, u32 max_slot)
3984 struct btrfs_fs_info *fs_info = root->fs_info;
3985 struct extent_buffer *right = path->nodes[0];
3986 struct extent_buffer *left;
3992 slot = path->slots[1];
3995 if (!path->nodes[1])
3998 right_nritems = btrfs_header_nritems(right);
3999 if (right_nritems == 0)
4002 btrfs_assert_tree_locked(path->nodes[1]);
4004 left = read_node_slot(fs_info, path->nodes[1], slot - 1);
4006 * slot - 1 is not valid or we fail to read the left node,
4007 * no big deal, just return.
4012 btrfs_tree_lock(left);
4013 btrfs_set_lock_blocking(left);
4015 free_space = btrfs_leaf_free_space(fs_info, left);
4016 if (free_space < data_size) {
4021 /* cow and double check */
4022 ret = btrfs_cow_block(trans, root, left,
4023 path->nodes[1], slot - 1, &left);
4025 /* we hit -ENOSPC, but it isn't fatal here */
4031 free_space = btrfs_leaf_free_space(fs_info, left);
4032 if (free_space < data_size) {
4037 return __push_leaf_left(fs_info, path, min_data_size,
4038 empty, left, free_space, right_nritems,
4041 btrfs_tree_unlock(left);
4042 free_extent_buffer(left);
4047 * split the path's leaf in two, making sure there is at least data_size
4048 * available for the resulting leaf level of the path.
4050 static noinline void copy_for_split(struct btrfs_trans_handle *trans,
4051 struct btrfs_fs_info *fs_info,
4052 struct btrfs_path *path,
4053 struct extent_buffer *l,
4054 struct extent_buffer *right,
4055 int slot, int mid, int nritems)
4060 struct btrfs_disk_key disk_key;
4061 struct btrfs_map_token token;
4063 btrfs_init_map_token(&token);
4065 nritems = nritems - mid;
4066 btrfs_set_header_nritems(right, nritems);
4067 data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(fs_info, l);
4069 copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
4070 btrfs_item_nr_offset(mid),
4071 nritems * sizeof(struct btrfs_item));
4073 copy_extent_buffer(right, l,
4074 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(fs_info) -
4075 data_copy_size, btrfs_leaf_data(l) +
4076 leaf_data_end(fs_info, l), data_copy_size);
4078 rt_data_off = BTRFS_LEAF_DATA_SIZE(fs_info) - btrfs_item_end_nr(l, mid);
4080 for (i = 0; i < nritems; i++) {
4081 struct btrfs_item *item = btrfs_item_nr(i);
4084 ioff = btrfs_token_item_offset(right, item, &token);
4085 btrfs_set_token_item_offset(right, item,
4086 ioff + rt_data_off, &token);
4089 btrfs_set_header_nritems(l, mid);
4090 btrfs_item_key(right, &disk_key, 0);
4091 insert_ptr(trans, fs_info, path, &disk_key, right->start,
4092 path->slots[1] + 1, 1);
4094 btrfs_mark_buffer_dirty(right);
4095 btrfs_mark_buffer_dirty(l);
4096 BUG_ON(path->slots[0] != slot);
4099 btrfs_tree_unlock(path->nodes[0]);
4100 free_extent_buffer(path->nodes[0]);
4101 path->nodes[0] = right;
4102 path->slots[0] -= mid;
4103 path->slots[1] += 1;
4105 btrfs_tree_unlock(right);
4106 free_extent_buffer(right);
4109 BUG_ON(path->slots[0] < 0);
4113 * double splits happen when we need to insert a big item in the middle
4114 * of a leaf. A double split can leave us with 3 mostly empty leaves:
4115 * leaf: [ slots 0 - N] [ our target ] [ N + 1 - total in leaf ]
4118 * We avoid this by trying to push the items on either side of our target
4119 * into the adjacent leaves. If all goes well we can avoid the double split
4122 static noinline int push_for_double_split(struct btrfs_trans_handle *trans,
4123 struct btrfs_root *root,
4124 struct btrfs_path *path,
4127 struct btrfs_fs_info *fs_info = root->fs_info;
4132 int space_needed = data_size;
4134 slot = path->slots[0];
4135 if (slot < btrfs_header_nritems(path->nodes[0]))
4136 space_needed -= btrfs_leaf_free_space(fs_info, path->nodes[0]);
4139 * try to push all the items after our slot into the
4142 ret = push_leaf_right(trans, root, path, 1, space_needed, 0, slot);
4149 nritems = btrfs_header_nritems(path->nodes[0]);
4151 * our goal is to get our slot at the start or end of a leaf. If
4152 * we've done so we're done
4154 if (path->slots[0] == 0 || path->slots[0] == nritems)
4157 if (btrfs_leaf_free_space(fs_info, path->nodes[0]) >= data_size)
4160 /* try to push all the items before our slot into the next leaf */
4161 slot = path->slots[0];
4162 ret = push_leaf_left(trans, root, path, 1, space_needed, 0, slot);
4175 * split the path's leaf in two, making sure there is at least data_size
4176 * available for the resulting leaf level of the path.
4178 * returns 0 if all went well and < 0 on failure.
4180 static noinline int split_leaf(struct btrfs_trans_handle *trans,
4181 struct btrfs_root *root,
4182 const struct btrfs_key *ins_key,
4183 struct btrfs_path *path, int data_size,
4186 struct btrfs_disk_key disk_key;
4187 struct extent_buffer *l;
4191 struct extent_buffer *right;
4192 struct btrfs_fs_info *fs_info = root->fs_info;
4196 int num_doubles = 0;
4197 int tried_avoid_double = 0;
4200 slot = path->slots[0];
4201 if (extend && data_size + btrfs_item_size_nr(l, slot) +
4202 sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(fs_info))
4205 /* first try to make some room by pushing left and right */
4206 if (data_size && path->nodes[1]) {
4207 int space_needed = data_size;
4209 if (slot < btrfs_header_nritems(l))
4210 space_needed -= btrfs_leaf_free_space(fs_info, l);
4212 wret = push_leaf_right(trans, root, path, space_needed,
4213 space_needed, 0, 0);
4217 wret = push_leaf_left(trans, root, path, space_needed,
4218 space_needed, 0, (u32)-1);
4224 /* did the pushes work? */
4225 if (btrfs_leaf_free_space(fs_info, l) >= data_size)
4229 if (!path->nodes[1]) {
4230 ret = insert_new_root(trans, root, path, 1);
4237 slot = path->slots[0];
4238 nritems = btrfs_header_nritems(l);
4239 mid = (nritems + 1) / 2;
4243 leaf_space_used(l, mid, nritems - mid) + data_size >
4244 BTRFS_LEAF_DATA_SIZE(fs_info)) {
4245 if (slot >= nritems) {
4249 if (mid != nritems &&
4250 leaf_space_used(l, mid, nritems - mid) +
4251 data_size > BTRFS_LEAF_DATA_SIZE(fs_info)) {
4252 if (data_size && !tried_avoid_double)
4253 goto push_for_double;
4259 if (leaf_space_used(l, 0, mid) + data_size >
4260 BTRFS_LEAF_DATA_SIZE(fs_info)) {
4261 if (!extend && data_size && slot == 0) {
4263 } else if ((extend || !data_size) && slot == 0) {
4267 if (mid != nritems &&
4268 leaf_space_used(l, mid, nritems - mid) +
4269 data_size > BTRFS_LEAF_DATA_SIZE(fs_info)) {
4270 if (data_size && !tried_avoid_double)
4271 goto push_for_double;
4279 btrfs_cpu_key_to_disk(&disk_key, ins_key);
4281 btrfs_item_key(l, &disk_key, mid);
4283 right = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid,
4284 &disk_key, 0, l->start, 0);
4286 return PTR_ERR(right);
4288 root_add_used(root, fs_info->nodesize);
4290 memzero_extent_buffer(right, 0, sizeof(struct btrfs_header));
4291 btrfs_set_header_bytenr(right, right->start);
4292 btrfs_set_header_generation(right, trans->transid);
4293 btrfs_set_header_backref_rev(right, BTRFS_MIXED_BACKREF_REV);
4294 btrfs_set_header_owner(right, root->root_key.objectid);
4295 btrfs_set_header_level(right, 0);
4296 write_extent_buffer_fsid(right, fs_info->fsid);
4297 write_extent_buffer_chunk_tree_uuid(right, fs_info->chunk_tree_uuid);
4301 btrfs_set_header_nritems(right, 0);
4302 insert_ptr(trans, fs_info, path, &disk_key,
4303 right->start, path->slots[1] + 1, 1);
4304 btrfs_tree_unlock(path->nodes[0]);
4305 free_extent_buffer(path->nodes[0]);
4306 path->nodes[0] = right;
4308 path->slots[1] += 1;
4310 btrfs_set_header_nritems(right, 0);
4311 insert_ptr(trans, fs_info, path, &disk_key,
4312 right->start, path->slots[1], 1);
4313 btrfs_tree_unlock(path->nodes[0]);
4314 free_extent_buffer(path->nodes[0]);
4315 path->nodes[0] = right;
4317 if (path->slots[1] == 0)
4318 fixup_low_keys(fs_info, path, &disk_key, 1);
4321 * We create a new leaf 'right' for the required ins_len and
4322 * we'll do btrfs_mark_buffer_dirty() on this leaf after copying
4323 * the content of ins_len to 'right'.
4328 copy_for_split(trans, fs_info, path, l, right, slot, mid, nritems);
4331 BUG_ON(num_doubles != 0);
4339 push_for_double_split(trans, root, path, data_size);
4340 tried_avoid_double = 1;
4341 if (btrfs_leaf_free_space(fs_info, path->nodes[0]) >= data_size)
4346 static noinline int setup_leaf_for_split(struct btrfs_trans_handle *trans,
4347 struct btrfs_root *root,
4348 struct btrfs_path *path, int ins_len)
4350 struct btrfs_fs_info *fs_info = root->fs_info;
4351 struct btrfs_key key;
4352 struct extent_buffer *leaf;
4353 struct btrfs_file_extent_item *fi;
4358 leaf = path->nodes[0];
4359 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4361 BUG_ON(key.type != BTRFS_EXTENT_DATA_KEY &&
4362 key.type != BTRFS_EXTENT_CSUM_KEY);
4364 if (btrfs_leaf_free_space(fs_info, leaf) >= ins_len)
4367 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
4368 if (key.type == BTRFS_EXTENT_DATA_KEY) {
4369 fi = btrfs_item_ptr(leaf, path->slots[0],
4370 struct btrfs_file_extent_item);
4371 extent_len = btrfs_file_extent_num_bytes(leaf, fi);
4373 btrfs_release_path(path);
4375 path->keep_locks = 1;
4376 path->search_for_split = 1;
4377 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
4378 path->search_for_split = 0;
4385 leaf = path->nodes[0];
4386 /* if our item isn't there, return now */
4387 if (item_size != btrfs_item_size_nr(leaf, path->slots[0]))
4390 /* the leaf has changed, it now has room. return now */
4391 if (btrfs_leaf_free_space(fs_info, path->nodes[0]) >= ins_len)
4394 if (key.type == BTRFS_EXTENT_DATA_KEY) {
4395 fi = btrfs_item_ptr(leaf, path->slots[0],
4396 struct btrfs_file_extent_item);
4397 if (extent_len != btrfs_file_extent_num_bytes(leaf, fi))
4401 btrfs_set_path_blocking(path);
4402 ret = split_leaf(trans, root, &key, path, ins_len, 1);
4406 path->keep_locks = 0;
4407 btrfs_unlock_up_safe(path, 1);
4410 path->keep_locks = 0;
4414 static noinline int split_item(struct btrfs_fs_info *fs_info,
4415 struct btrfs_path *path,
4416 const struct btrfs_key *new_key,
4417 unsigned long split_offset)
4419 struct extent_buffer *leaf;
4420 struct btrfs_item *item;
4421 struct btrfs_item *new_item;
4427 struct btrfs_disk_key disk_key;
4429 leaf = path->nodes[0];
4430 BUG_ON(btrfs_leaf_free_space(fs_info, leaf) < sizeof(struct btrfs_item));
4432 btrfs_set_path_blocking(path);
4434 item = btrfs_item_nr(path->slots[0]);
4435 orig_offset = btrfs_item_offset(leaf, item);
4436 item_size = btrfs_item_size(leaf, item);
4438 buf = kmalloc(item_size, GFP_NOFS);
4442 read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf,
4443 path->slots[0]), item_size);
4445 slot = path->slots[0] + 1;
4446 nritems = btrfs_header_nritems(leaf);
4447 if (slot != nritems) {
4448 /* shift the items */
4449 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1),
4450 btrfs_item_nr_offset(slot),
4451 (nritems - slot) * sizeof(struct btrfs_item));
4454 btrfs_cpu_key_to_disk(&disk_key, new_key);
4455 btrfs_set_item_key(leaf, &disk_key, slot);
4457 new_item = btrfs_item_nr(slot);
4459 btrfs_set_item_offset(leaf, new_item, orig_offset);
4460 btrfs_set_item_size(leaf, new_item, item_size - split_offset);
4462 btrfs_set_item_offset(leaf, item,
4463 orig_offset + item_size - split_offset);
4464 btrfs_set_item_size(leaf, item, split_offset);
4466 btrfs_set_header_nritems(leaf, nritems + 1);
4468 /* write the data for the start of the original item */
4469 write_extent_buffer(leaf, buf,
4470 btrfs_item_ptr_offset(leaf, path->slots[0]),
4473 /* write the data for the new item */
4474 write_extent_buffer(leaf, buf + split_offset,
4475 btrfs_item_ptr_offset(leaf, slot),
4476 item_size - split_offset);
4477 btrfs_mark_buffer_dirty(leaf);
4479 BUG_ON(btrfs_leaf_free_space(fs_info, leaf) < 0);
4485 * This function splits a single item into two items,
4486 * giving 'new_key' to the new item and splitting the
4487 * old one at split_offset (from the start of the item).
4489 * The path may be released by this operation. After
4490 * the split, the path is pointing to the old item. The
4491 * new item is going to be in the same node as the old one.
4493 * Note, the item being split must be smaller enough to live alone on
4494 * a tree block with room for one extra struct btrfs_item
4496 * This allows us to split the item in place, keeping a lock on the
4497 * leaf the entire time.
4499 int btrfs_split_item(struct btrfs_trans_handle *trans,
4500 struct btrfs_root *root,
4501 struct btrfs_path *path,
4502 const struct btrfs_key *new_key,
4503 unsigned long split_offset)
4506 ret = setup_leaf_for_split(trans, root, path,
4507 sizeof(struct btrfs_item));
4511 ret = split_item(root->fs_info, path, new_key, split_offset);
4516 * This function duplicate a item, giving 'new_key' to the new item.
4517 * It guarantees both items live in the same tree leaf and the new item
4518 * is contiguous with the original item.
4520 * This allows us to split file extent in place, keeping a lock on the
4521 * leaf the entire time.
4523 int btrfs_duplicate_item(struct btrfs_trans_handle *trans,
4524 struct btrfs_root *root,
4525 struct btrfs_path *path,
4526 const struct btrfs_key *new_key)
4528 struct extent_buffer *leaf;
4532 leaf = path->nodes[0];
4533 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
4534 ret = setup_leaf_for_split(trans, root, path,
4535 item_size + sizeof(struct btrfs_item));
4540 setup_items_for_insert(root, path, new_key, &item_size,
4541 item_size, item_size +
4542 sizeof(struct btrfs_item), 1);
4543 leaf = path->nodes[0];
4544 memcpy_extent_buffer(leaf,
4545 btrfs_item_ptr_offset(leaf, path->slots[0]),
4546 btrfs_item_ptr_offset(leaf, path->slots[0] - 1),
4552 * make the item pointed to by the path smaller. new_size indicates
4553 * how small to make it, and from_end tells us if we just chop bytes
4554 * off the end of the item or if we shift the item to chop bytes off
4557 void btrfs_truncate_item(struct btrfs_fs_info *fs_info,
4558 struct btrfs_path *path, u32 new_size, int from_end)
4561 struct extent_buffer *leaf;
4562 struct btrfs_item *item;
4564 unsigned int data_end;
4565 unsigned int old_data_start;
4566 unsigned int old_size;
4567 unsigned int size_diff;
4569 struct btrfs_map_token token;
4571 btrfs_init_map_token(&token);
4573 leaf = path->nodes[0];
4574 slot = path->slots[0];
4576 old_size = btrfs_item_size_nr(leaf, slot);
4577 if (old_size == new_size)
4580 nritems = btrfs_header_nritems(leaf);
4581 data_end = leaf_data_end(fs_info, leaf);
4583 old_data_start = btrfs_item_offset_nr(leaf, slot);
4585 size_diff = old_size - new_size;
4588 BUG_ON(slot >= nritems);
4591 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4593 /* first correct the data pointers */
4594 for (i = slot; i < nritems; i++) {
4596 item = btrfs_item_nr(i);
4598 ioff = btrfs_token_item_offset(leaf, item, &token);
4599 btrfs_set_token_item_offset(leaf, item,
4600 ioff + size_diff, &token);
4603 /* shift the data */
4605 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
4606 data_end + size_diff, btrfs_leaf_data(leaf) +
4607 data_end, old_data_start + new_size - data_end);
4609 struct btrfs_disk_key disk_key;
4612 btrfs_item_key(leaf, &disk_key, slot);
4614 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
4616 struct btrfs_file_extent_item *fi;
4618 fi = btrfs_item_ptr(leaf, slot,
4619 struct btrfs_file_extent_item);
4620 fi = (struct btrfs_file_extent_item *)(
4621 (unsigned long)fi - size_diff);
4623 if (btrfs_file_extent_type(leaf, fi) ==
4624 BTRFS_FILE_EXTENT_INLINE) {
4625 ptr = btrfs_item_ptr_offset(leaf, slot);
4626 memmove_extent_buffer(leaf, ptr,
4628 BTRFS_FILE_EXTENT_INLINE_DATA_START);
4632 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
4633 data_end + size_diff, btrfs_leaf_data(leaf) +
4634 data_end, old_data_start - data_end);
4636 offset = btrfs_disk_key_offset(&disk_key);
4637 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
4638 btrfs_set_item_key(leaf, &disk_key, slot);
4640 fixup_low_keys(fs_info, path, &disk_key, 1);
4643 item = btrfs_item_nr(slot);
4644 btrfs_set_item_size(leaf, item, new_size);
4645 btrfs_mark_buffer_dirty(leaf);
4647 if (btrfs_leaf_free_space(fs_info, leaf) < 0) {
4648 btrfs_print_leaf(fs_info, leaf);
4654 * make the item pointed to by the path bigger, data_size is the added size.
4656 void btrfs_extend_item(struct btrfs_fs_info *fs_info, struct btrfs_path *path,
4660 struct extent_buffer *leaf;
4661 struct btrfs_item *item;
4663 unsigned int data_end;
4664 unsigned int old_data;
4665 unsigned int old_size;
4667 struct btrfs_map_token token;
4669 btrfs_init_map_token(&token);
4671 leaf = path->nodes[0];
4673 nritems = btrfs_header_nritems(leaf);
4674 data_end = leaf_data_end(fs_info, leaf);
4676 if (btrfs_leaf_free_space(fs_info, leaf) < data_size) {
4677 btrfs_print_leaf(fs_info, leaf);
4680 slot = path->slots[0];
4681 old_data = btrfs_item_end_nr(leaf, slot);
4684 if (slot >= nritems) {
4685 btrfs_print_leaf(fs_info, leaf);
4686 btrfs_crit(fs_info, "slot %d too large, nritems %d",
4692 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4694 /* first correct the data pointers */
4695 for (i = slot; i < nritems; i++) {
4697 item = btrfs_item_nr(i);
4699 ioff = btrfs_token_item_offset(leaf, item, &token);
4700 btrfs_set_token_item_offset(leaf, item,
4701 ioff - data_size, &token);
4704 /* shift the data */
4705 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
4706 data_end - data_size, btrfs_leaf_data(leaf) +
4707 data_end, old_data - data_end);
4709 data_end = old_data;
4710 old_size = btrfs_item_size_nr(leaf, slot);
4711 item = btrfs_item_nr(slot);
4712 btrfs_set_item_size(leaf, item, old_size + data_size);
4713 btrfs_mark_buffer_dirty(leaf);
4715 if (btrfs_leaf_free_space(fs_info, leaf) < 0) {
4716 btrfs_print_leaf(fs_info, leaf);
4722 * this is a helper for btrfs_insert_empty_items, the main goal here is
4723 * to save stack depth by doing the bulk of the work in a function
4724 * that doesn't call btrfs_search_slot
4726 void setup_items_for_insert(struct btrfs_root *root, struct btrfs_path *path,
4727 const struct btrfs_key *cpu_key, u32 *data_size,
4728 u32 total_data, u32 total_size, int nr)
4730 struct btrfs_fs_info *fs_info = root->fs_info;
4731 struct btrfs_item *item;
4734 unsigned int data_end;
4735 struct btrfs_disk_key disk_key;
4736 struct extent_buffer *leaf;
4738 struct btrfs_map_token token;
4740 if (path->slots[0] == 0) {
4741 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
4742 fixup_low_keys(fs_info, path, &disk_key, 1);
4744 btrfs_unlock_up_safe(path, 1);
4746 btrfs_init_map_token(&token);
4748 leaf = path->nodes[0];
4749 slot = path->slots[0];
4751 nritems = btrfs_header_nritems(leaf);
4752 data_end = leaf_data_end(fs_info, leaf);
4754 if (btrfs_leaf_free_space(fs_info, leaf) < total_size) {
4755 btrfs_print_leaf(fs_info, leaf);
4756 btrfs_crit(fs_info, "not enough freespace need %u have %d",
4757 total_size, btrfs_leaf_free_space(fs_info, leaf));
4761 if (slot != nritems) {
4762 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
4764 if (old_data < data_end) {
4765 btrfs_print_leaf(fs_info, leaf);
4766 btrfs_crit(fs_info, "slot %d old_data %d data_end %d",
4767 slot, old_data, data_end);
4771 * item0..itemN ... dataN.offset..dataN.size .. data0.size
4773 /* first correct the data pointers */
4774 for (i = slot; i < nritems; i++) {
4777 item = btrfs_item_nr(i);
4778 ioff = btrfs_token_item_offset(leaf, item, &token);
4779 btrfs_set_token_item_offset(leaf, item,
4780 ioff - total_data, &token);
4782 /* shift the items */
4783 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
4784 btrfs_item_nr_offset(slot),
4785 (nritems - slot) * sizeof(struct btrfs_item));
4787 /* shift the data */
4788 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
4789 data_end - total_data, btrfs_leaf_data(leaf) +
4790 data_end, old_data - data_end);
4791 data_end = old_data;
4794 /* setup the item for the new data */
4795 for (i = 0; i < nr; i++) {
4796 btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
4797 btrfs_set_item_key(leaf, &disk_key, slot + i);
4798 item = btrfs_item_nr(slot + i);
4799 btrfs_set_token_item_offset(leaf, item,
4800 data_end - data_size[i], &token);
4801 data_end -= data_size[i];
4802 btrfs_set_token_item_size(leaf, item, data_size[i], &token);
4805 btrfs_set_header_nritems(leaf, nritems + nr);
4806 btrfs_mark_buffer_dirty(leaf);
4808 if (btrfs_leaf_free_space(fs_info, leaf) < 0) {
4809 btrfs_print_leaf(fs_info, leaf);
4815 * Given a key and some data, insert items into the tree.
4816 * This does all the path init required, making room in the tree if needed.
4818 int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
4819 struct btrfs_root *root,
4820 struct btrfs_path *path,
4821 const struct btrfs_key *cpu_key, u32 *data_size,
4830 for (i = 0; i < nr; i++)
4831 total_data += data_size[i];
4833 total_size = total_data + (nr * sizeof(struct btrfs_item));
4834 ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
4840 slot = path->slots[0];
4843 setup_items_for_insert(root, path, cpu_key, data_size,
4844 total_data, total_size, nr);
4849 * Given a key and some data, insert an item into the tree.
4850 * This does all the path init required, making room in the tree if needed.
4852 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
4853 const struct btrfs_key *cpu_key, void *data,
4857 struct btrfs_path *path;
4858 struct extent_buffer *leaf;
4861 path = btrfs_alloc_path();
4864 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
4866 leaf = path->nodes[0];
4867 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
4868 write_extent_buffer(leaf, data, ptr, data_size);
4869 btrfs_mark_buffer_dirty(leaf);
4871 btrfs_free_path(path);
4876 * delete the pointer from a given node.
4878 * the tree should have been previously balanced so the deletion does not
4881 static void del_ptr(struct btrfs_root *root, struct btrfs_path *path,
4882 int level, int slot)
4884 struct btrfs_fs_info *fs_info = root->fs_info;
4885 struct extent_buffer *parent = path->nodes[level];
4889 nritems = btrfs_header_nritems(parent);
4890 if (slot != nritems - 1) {
4892 tree_mod_log_eb_move(fs_info, parent, slot,
4893 slot + 1, nritems - slot - 1);
4894 memmove_extent_buffer(parent,
4895 btrfs_node_key_ptr_offset(slot),
4896 btrfs_node_key_ptr_offset(slot + 1),
4897 sizeof(struct btrfs_key_ptr) *
4898 (nritems - slot - 1));
4900 ret = tree_mod_log_insert_key(fs_info, parent, slot,
4901 MOD_LOG_KEY_REMOVE, GFP_NOFS);
4906 btrfs_set_header_nritems(parent, nritems);
4907 if (nritems == 0 && parent == root->node) {
4908 BUG_ON(btrfs_header_level(root->node) != 1);
4909 /* just turn the root into a leaf and break */
4910 btrfs_set_header_level(root->node, 0);
4911 } else if (slot == 0) {
4912 struct btrfs_disk_key disk_key;
4914 btrfs_node_key(parent, &disk_key, 0);
4915 fixup_low_keys(fs_info, path, &disk_key, level + 1);
4917 btrfs_mark_buffer_dirty(parent);
4921 * a helper function to delete the leaf pointed to by path->slots[1] and
4924 * This deletes the pointer in path->nodes[1] and frees the leaf
4925 * block extent. zero is returned if it all worked out, < 0 otherwise.
4927 * The path must have already been setup for deleting the leaf, including
4928 * all the proper balancing. path->nodes[1] must be locked.
4930 static noinline void btrfs_del_leaf(struct btrfs_trans_handle *trans,
4931 struct btrfs_root *root,
4932 struct btrfs_path *path,
4933 struct extent_buffer *leaf)
4935 WARN_ON(btrfs_header_generation(leaf) != trans->transid);
4936 del_ptr(root, path, 1, path->slots[1]);
4939 * btrfs_free_extent is expensive, we want to make sure we
4940 * aren't holding any locks when we call it
4942 btrfs_unlock_up_safe(path, 0);
4944 root_sub_used(root, leaf->len);
4946 extent_buffer_get(leaf);
4947 btrfs_free_tree_block(trans, root, leaf, 0, 1);
4948 free_extent_buffer_stale(leaf);
4951 * delete the item at the leaf level in path. If that empties
4952 * the leaf, remove it from the tree
4954 int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
4955 struct btrfs_path *path, int slot, int nr)
4957 struct btrfs_fs_info *fs_info = root->fs_info;
4958 struct extent_buffer *leaf;
4959 struct btrfs_item *item;
4966 struct btrfs_map_token token;
4968 btrfs_init_map_token(&token);
4970 leaf = path->nodes[0];
4971 last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
4973 for (i = 0; i < nr; i++)
4974 dsize += btrfs_item_size_nr(leaf, slot + i);
4976 nritems = btrfs_header_nritems(leaf);
4978 if (slot + nr != nritems) {
4979 int data_end = leaf_data_end(fs_info, leaf);
4981 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
4983 btrfs_leaf_data(leaf) + data_end,
4984 last_off - data_end);
4986 for (i = slot + nr; i < nritems; i++) {
4989 item = btrfs_item_nr(i);
4990 ioff = btrfs_token_item_offset(leaf, item, &token);
4991 btrfs_set_token_item_offset(leaf, item,
4992 ioff + dsize, &token);
4995 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
4996 btrfs_item_nr_offset(slot + nr),
4997 sizeof(struct btrfs_item) *
4998 (nritems - slot - nr));
5000 btrfs_set_header_nritems(leaf, nritems - nr);
5003 /* delete the leaf if we've emptied it */
5005 if (leaf == root->node) {
5006 btrfs_set_header_level(leaf, 0);
5008 btrfs_set_path_blocking(path);
5009 clean_tree_block(fs_info, leaf);
5010 btrfs_del_leaf(trans, root, path, leaf);
5013 int used = leaf_space_used(leaf, 0, nritems);
5015 struct btrfs_disk_key disk_key;
5017 btrfs_item_key(leaf, &disk_key, 0);
5018 fixup_low_keys(fs_info, path, &disk_key, 1);
5021 /* delete the leaf if it is mostly empty */
5022 if (used < BTRFS_LEAF_DATA_SIZE(fs_info) / 3) {
5023 /* push_leaf_left fixes the path.
5024 * make sure the path still points to our leaf
5025 * for possible call to del_ptr below
5027 slot = path->slots[1];
5028 extent_buffer_get(leaf);
5030 btrfs_set_path_blocking(path);
5031 wret = push_leaf_left(trans, root, path, 1, 1,
5033 if (wret < 0 && wret != -ENOSPC)
5036 if (path->nodes[0] == leaf &&
5037 btrfs_header_nritems(leaf)) {
5038 wret = push_leaf_right(trans, root, path, 1,
5040 if (wret < 0 && wret != -ENOSPC)
5044 if (btrfs_header_nritems(leaf) == 0) {
5045 path->slots[1] = slot;
5046 btrfs_del_leaf(trans, root, path, leaf);
5047 free_extent_buffer(leaf);
5050 /* if we're still in the path, make sure
5051 * we're dirty. Otherwise, one of the
5052 * push_leaf functions must have already
5053 * dirtied this buffer
5055 if (path->nodes[0] == leaf)
5056 btrfs_mark_buffer_dirty(leaf);
5057 free_extent_buffer(leaf);
5060 btrfs_mark_buffer_dirty(leaf);
5067 * search the tree again to find a leaf with lesser keys
5068 * returns 0 if it found something or 1 if there are no lesser leaves.
5069 * returns < 0 on io errors.
5071 * This may release the path, and so you may lose any locks held at the
5074 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
5076 struct btrfs_key key;
5077 struct btrfs_disk_key found_key;
5080 btrfs_item_key_to_cpu(path->nodes[0], &key, 0);
5082 if (key.offset > 0) {
5084 } else if (key.type > 0) {
5086 key.offset = (u64)-1;
5087 } else if (key.objectid > 0) {
5090 key.offset = (u64)-1;
5095 btrfs_release_path(path);
5096 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5099 btrfs_item_key(path->nodes[0], &found_key, 0);
5100 ret = comp_keys(&found_key, &key);
5102 * We might have had an item with the previous key in the tree right
5103 * before we released our path. And after we released our path, that
5104 * item might have been pushed to the first slot (0) of the leaf we
5105 * were holding due to a tree balance. Alternatively, an item with the
5106 * previous key can exist as the only element of a leaf (big fat item).
5107 * Therefore account for these 2 cases, so that our callers (like
5108 * btrfs_previous_item) don't miss an existing item with a key matching
5109 * the previous key we computed above.
5117 * A helper function to walk down the tree starting at min_key, and looking
5118 * for nodes or leaves that are have a minimum transaction id.
5119 * This is used by the btree defrag code, and tree logging
5121 * This does not cow, but it does stuff the starting key it finds back
5122 * into min_key, so you can call btrfs_search_slot with cow=1 on the
5123 * key and get a writable path.
5125 * This does lock as it descends, and path->keep_locks should be set
5126 * to 1 by the caller.
5128 * This honors path->lowest_level to prevent descent past a given level
5131 * min_trans indicates the oldest transaction that you are interested
5132 * in walking through. Any nodes or leaves older than min_trans are
5133 * skipped over (without reading them).
5135 * returns zero if something useful was found, < 0 on error and 1 if there
5136 * was nothing in the tree that matched the search criteria.
5138 int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
5139 struct btrfs_path *path,
5142 struct btrfs_fs_info *fs_info = root->fs_info;
5143 struct extent_buffer *cur;
5144 struct btrfs_key found_key;
5150 int keep_locks = path->keep_locks;
5152 path->keep_locks = 1;
5154 cur = btrfs_read_lock_root_node(root);
5155 level = btrfs_header_level(cur);
5156 WARN_ON(path->nodes[level]);
5157 path->nodes[level] = cur;
5158 path->locks[level] = BTRFS_READ_LOCK;
5160 if (btrfs_header_generation(cur) < min_trans) {
5165 nritems = btrfs_header_nritems(cur);
5166 level = btrfs_header_level(cur);
5167 sret = bin_search(cur, min_key, level, &slot);
5169 /* at the lowest level, we're done, setup the path and exit */
5170 if (level == path->lowest_level) {
5171 if (slot >= nritems)
5174 path->slots[level] = slot;
5175 btrfs_item_key_to_cpu(cur, &found_key, slot);
5178 if (sret && slot > 0)
5181 * check this node pointer against the min_trans parameters.
5182 * If it is too old, old, skip to the next one.
5184 while (slot < nritems) {
5187 gen = btrfs_node_ptr_generation(cur, slot);
5188 if (gen < min_trans) {
5196 * we didn't find a candidate key in this node, walk forward
5197 * and find another one
5199 if (slot >= nritems) {
5200 path->slots[level] = slot;
5201 btrfs_set_path_blocking(path);
5202 sret = btrfs_find_next_key(root, path, min_key, level,
5205 btrfs_release_path(path);
5211 /* save our key for returning back */
5212 btrfs_node_key_to_cpu(cur, &found_key, slot);
5213 path->slots[level] = slot;
5214 if (level == path->lowest_level) {
5218 btrfs_set_path_blocking(path);
5219 cur = read_node_slot(fs_info, cur, slot);
5225 btrfs_tree_read_lock(cur);
5227 path->locks[level - 1] = BTRFS_READ_LOCK;
5228 path->nodes[level - 1] = cur;
5229 unlock_up(path, level, 1, 0, NULL);
5230 btrfs_clear_path_blocking(path, NULL, 0);
5233 path->keep_locks = keep_locks;
5235 btrfs_unlock_up_safe(path, path->lowest_level + 1);
5236 btrfs_set_path_blocking(path);
5237 memcpy(min_key, &found_key, sizeof(found_key));
5242 static int tree_move_down(struct btrfs_fs_info *fs_info,
5243 struct btrfs_path *path,
5246 struct extent_buffer *eb;
5248 BUG_ON(*level == 0);
5249 eb = read_node_slot(fs_info, path->nodes[*level], path->slots[*level]);
5253 path->nodes[*level - 1] = eb;
5254 path->slots[*level - 1] = 0;
5259 static int tree_move_next_or_upnext(struct btrfs_path *path,
5260 int *level, int root_level)
5264 nritems = btrfs_header_nritems(path->nodes[*level]);
5266 path->slots[*level]++;
5268 while (path->slots[*level] >= nritems) {
5269 if (*level == root_level)
5273 path->slots[*level] = 0;
5274 free_extent_buffer(path->nodes[*level]);
5275 path->nodes[*level] = NULL;
5277 path->slots[*level]++;
5279 nritems = btrfs_header_nritems(path->nodes[*level]);
5286 * Returns 1 if it had to move up and next. 0 is returned if it moved only next
5289 static int tree_advance(struct btrfs_fs_info *fs_info,
5290 struct btrfs_path *path,
5291 int *level, int root_level,
5293 struct btrfs_key *key)
5297 if (*level == 0 || !allow_down) {
5298 ret = tree_move_next_or_upnext(path, level, root_level);
5300 ret = tree_move_down(fs_info, path, level);
5304 btrfs_item_key_to_cpu(path->nodes[*level], key,
5305 path->slots[*level]);
5307 btrfs_node_key_to_cpu(path->nodes[*level], key,
5308 path->slots[*level]);
5313 static int tree_compare_item(struct btrfs_path *left_path,
5314 struct btrfs_path *right_path,
5319 unsigned long off1, off2;
5321 len1 = btrfs_item_size_nr(left_path->nodes[0], left_path->slots[0]);
5322 len2 = btrfs_item_size_nr(right_path->nodes[0], right_path->slots[0]);
5326 off1 = btrfs_item_ptr_offset(left_path->nodes[0], left_path->slots[0]);
5327 off2 = btrfs_item_ptr_offset(right_path->nodes[0],
5328 right_path->slots[0]);
5330 read_extent_buffer(left_path->nodes[0], tmp_buf, off1, len1);
5332 cmp = memcmp_extent_buffer(right_path->nodes[0], tmp_buf, off2, len1);
5339 #define ADVANCE_ONLY_NEXT -1
5342 * This function compares two trees and calls the provided callback for
5343 * every changed/new/deleted item it finds.
5344 * If shared tree blocks are encountered, whole subtrees are skipped, making
5345 * the compare pretty fast on snapshotted subvolumes.
5347 * This currently works on commit roots only. As commit roots are read only,
5348 * we don't do any locking. The commit roots are protected with transactions.
5349 * Transactions are ended and rejoined when a commit is tried in between.
5351 * This function checks for modifications done to the trees while comparing.
5352 * If it detects a change, it aborts immediately.
5354 int btrfs_compare_trees(struct btrfs_root *left_root,
5355 struct btrfs_root *right_root,
5356 btrfs_changed_cb_t changed_cb, void *ctx)
5358 struct btrfs_fs_info *fs_info = left_root->fs_info;
5361 struct btrfs_path *left_path = NULL;
5362 struct btrfs_path *right_path = NULL;
5363 struct btrfs_key left_key;
5364 struct btrfs_key right_key;
5365 char *tmp_buf = NULL;
5366 int left_root_level;
5367 int right_root_level;
5370 int left_end_reached;
5371 int right_end_reached;
5379 left_path = btrfs_alloc_path();
5384 right_path = btrfs_alloc_path();
5390 tmp_buf = kmalloc(fs_info->nodesize, GFP_KERNEL | __GFP_NOWARN);
5392 tmp_buf = vmalloc(fs_info->nodesize);
5399 left_path->search_commit_root = 1;
5400 left_path->skip_locking = 1;
5401 right_path->search_commit_root = 1;
5402 right_path->skip_locking = 1;
5405 * Strategy: Go to the first items of both trees. Then do
5407 * If both trees are at level 0
5408 * Compare keys of current items
5409 * If left < right treat left item as new, advance left tree
5411 * If left > right treat right item as deleted, advance right tree
5413 * If left == right do deep compare of items, treat as changed if
5414 * needed, advance both trees and repeat
5415 * If both trees are at the same level but not at level 0
5416 * Compare keys of current nodes/leafs
5417 * If left < right advance left tree and repeat
5418 * If left > right advance right tree and repeat
5419 * If left == right compare blockptrs of the next nodes/leafs
5420 * If they match advance both trees but stay at the same level
5422 * If they don't match advance both trees while allowing to go
5424 * If tree levels are different
5425 * Advance the tree that needs it and repeat
5427 * Advancing a tree means:
5428 * If we are at level 0, try to go to the next slot. If that's not
5429 * possible, go one level up and repeat. Stop when we found a level
5430 * where we could go to the next slot. We may at this point be on a
5433 * If we are not at level 0 and not on shared tree blocks, go one
5436 * If we are not at level 0 and on shared tree blocks, go one slot to
5437 * the right if possible or go up and right.
5440 down_read(&fs_info->commit_root_sem);
5441 left_level = btrfs_header_level(left_root->commit_root);
5442 left_root_level = left_level;
5443 left_path->nodes[left_level] = left_root->commit_root;
5444 extent_buffer_get(left_path->nodes[left_level]);
5446 right_level = btrfs_header_level(right_root->commit_root);
5447 right_root_level = right_level;
5448 right_path->nodes[right_level] = right_root->commit_root;
5449 extent_buffer_get(right_path->nodes[right_level]);
5450 up_read(&fs_info->commit_root_sem);
5452 if (left_level == 0)
5453 btrfs_item_key_to_cpu(left_path->nodes[left_level],
5454 &left_key, left_path->slots[left_level]);
5456 btrfs_node_key_to_cpu(left_path->nodes[left_level],
5457 &left_key, left_path->slots[left_level]);
5458 if (right_level == 0)
5459 btrfs_item_key_to_cpu(right_path->nodes[right_level],
5460 &right_key, right_path->slots[right_level]);
5462 btrfs_node_key_to_cpu(right_path->nodes[right_level],
5463 &right_key, right_path->slots[right_level]);
5465 left_end_reached = right_end_reached = 0;
5466 advance_left = advance_right = 0;
5469 if (advance_left && !left_end_reached) {
5470 ret = tree_advance(fs_info, left_path, &left_level,
5472 advance_left != ADVANCE_ONLY_NEXT,
5475 left_end_reached = ADVANCE;
5480 if (advance_right && !right_end_reached) {
5481 ret = tree_advance(fs_info, right_path, &right_level,
5483 advance_right != ADVANCE_ONLY_NEXT,
5486 right_end_reached = ADVANCE;
5492 if (left_end_reached && right_end_reached) {
5495 } else if (left_end_reached) {
5496 if (right_level == 0) {
5497 ret = changed_cb(left_root, right_root,
5498 left_path, right_path,
5500 BTRFS_COMPARE_TREE_DELETED,
5505 advance_right = ADVANCE;
5507 } else if (right_end_reached) {
5508 if (left_level == 0) {
5509 ret = changed_cb(left_root, right_root,
5510 left_path, right_path,
5512 BTRFS_COMPARE_TREE_NEW,
5517 advance_left = ADVANCE;
5521 if (left_level == 0 && right_level == 0) {
5522 cmp = btrfs_comp_cpu_keys(&left_key, &right_key);
5524 ret = changed_cb(left_root, right_root,
5525 left_path, right_path,
5527 BTRFS_COMPARE_TREE_NEW,
5531 advance_left = ADVANCE;
5532 } else if (cmp > 0) {
5533 ret = changed_cb(left_root, right_root,
5534 left_path, right_path,
5536 BTRFS_COMPARE_TREE_DELETED,
5540 advance_right = ADVANCE;
5542 enum btrfs_compare_tree_result result;
5544 WARN_ON(!extent_buffer_uptodate(left_path->nodes[0]));
5545 ret = tree_compare_item(left_path, right_path,
5548 result = BTRFS_COMPARE_TREE_CHANGED;
5550 result = BTRFS_COMPARE_TREE_SAME;
5551 ret = changed_cb(left_root, right_root,
5552 left_path, right_path,
5553 &left_key, result, ctx);
5556 advance_left = ADVANCE;
5557 advance_right = ADVANCE;
5559 } else if (left_level == right_level) {
5560 cmp = btrfs_comp_cpu_keys(&left_key, &right_key);
5562 advance_left = ADVANCE;
5563 } else if (cmp > 0) {
5564 advance_right = ADVANCE;
5566 left_blockptr = btrfs_node_blockptr(
5567 left_path->nodes[left_level],
5568 left_path->slots[left_level]);
5569 right_blockptr = btrfs_node_blockptr(
5570 right_path->nodes[right_level],
5571 right_path->slots[right_level]);
5572 left_gen = btrfs_node_ptr_generation(
5573 left_path->nodes[left_level],
5574 left_path->slots[left_level]);
5575 right_gen = btrfs_node_ptr_generation(
5576 right_path->nodes[right_level],
5577 right_path->slots[right_level]);
5578 if (left_blockptr == right_blockptr &&
5579 left_gen == right_gen) {
5581 * As we're on a shared block, don't
5582 * allow to go deeper.
5584 advance_left = ADVANCE_ONLY_NEXT;
5585 advance_right = ADVANCE_ONLY_NEXT;
5587 advance_left = ADVANCE;
5588 advance_right = ADVANCE;
5591 } else if (left_level < right_level) {
5592 advance_right = ADVANCE;
5594 advance_left = ADVANCE;
5599 btrfs_free_path(left_path);
5600 btrfs_free_path(right_path);
5606 * this is similar to btrfs_next_leaf, but does not try to preserve
5607 * and fixup the path. It looks for and returns the next key in the
5608 * tree based on the current path and the min_trans parameters.
5610 * 0 is returned if another key is found, < 0 if there are any errors
5611 * and 1 is returned if there are no higher keys in the tree
5613 * path->keep_locks should be set to 1 on the search made before
5614 * calling this function.
5616 int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
5617 struct btrfs_key *key, int level, u64 min_trans)
5620 struct extent_buffer *c;
5622 WARN_ON(!path->keep_locks);
5623 while (level < BTRFS_MAX_LEVEL) {
5624 if (!path->nodes[level])
5627 slot = path->slots[level] + 1;
5628 c = path->nodes[level];
5630 if (slot >= btrfs_header_nritems(c)) {
5633 struct btrfs_key cur_key;
5634 if (level + 1 >= BTRFS_MAX_LEVEL ||
5635 !path->nodes[level + 1])
5638 if (path->locks[level + 1]) {
5643 slot = btrfs_header_nritems(c) - 1;
5645 btrfs_item_key_to_cpu(c, &cur_key, slot);
5647 btrfs_node_key_to_cpu(c, &cur_key, slot);
5649 orig_lowest = path->lowest_level;
5650 btrfs_release_path(path);
5651 path->lowest_level = level;
5652 ret = btrfs_search_slot(NULL, root, &cur_key, path,
5654 path->lowest_level = orig_lowest;
5658 c = path->nodes[level];
5659 slot = path->slots[level];
5666 btrfs_item_key_to_cpu(c, key, slot);
5668 u64 gen = btrfs_node_ptr_generation(c, slot);
5670 if (gen < min_trans) {
5674 btrfs_node_key_to_cpu(c, key, slot);
5682 * search the tree again to find a leaf with greater keys
5683 * returns 0 if it found something or 1 if there are no greater leaves.
5684 * returns < 0 on io errors.
5686 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
5688 return btrfs_next_old_leaf(root, path, 0);
5691 int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
5696 struct extent_buffer *c;
5697 struct extent_buffer *next;
5698 struct btrfs_key key;
5701 int old_spinning = path->leave_spinning;
5702 int next_rw_lock = 0;
5704 nritems = btrfs_header_nritems(path->nodes[0]);
5708 btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1);
5713 btrfs_release_path(path);
5715 path->keep_locks = 1;
5716 path->leave_spinning = 1;
5719 ret = btrfs_search_old_slot(root, &key, path, time_seq);
5721 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5722 path->keep_locks = 0;
5727 nritems = btrfs_header_nritems(path->nodes[0]);
5729 * by releasing the path above we dropped all our locks. A balance
5730 * could have added more items next to the key that used to be
5731 * at the very end of the block. So, check again here and
5732 * advance the path if there are now more items available.
5734 if (nritems > 0 && path->slots[0] < nritems - 1) {
5741 * So the above check misses one case:
5742 * - after releasing the path above, someone has removed the item that
5743 * used to be at the very end of the block, and balance between leafs
5744 * gets another one with bigger key.offset to replace it.
5746 * This one should be returned as well, or we can get leaf corruption
5747 * later(esp. in __btrfs_drop_extents()).
5749 * And a bit more explanation about this check,
5750 * with ret > 0, the key isn't found, the path points to the slot
5751 * where it should be inserted, so the path->slots[0] item must be the
5754 if (nritems > 0 && ret > 0 && path->slots[0] == nritems - 1) {
5759 while (level < BTRFS_MAX_LEVEL) {
5760 if (!path->nodes[level]) {
5765 slot = path->slots[level] + 1;
5766 c = path->nodes[level];
5767 if (slot >= btrfs_header_nritems(c)) {
5769 if (level == BTRFS_MAX_LEVEL) {
5777 btrfs_tree_unlock_rw(next, next_rw_lock);
5778 free_extent_buffer(next);
5782 next_rw_lock = path->locks[level];
5783 ret = read_block_for_search(root, path, &next, level,
5789 btrfs_release_path(path);
5793 if (!path->skip_locking) {
5794 ret = btrfs_try_tree_read_lock(next);
5795 if (!ret && time_seq) {
5797 * If we don't get the lock, we may be racing
5798 * with push_leaf_left, holding that lock while
5799 * itself waiting for the leaf we've currently
5800 * locked. To solve this situation, we give up
5801 * on our lock and cycle.
5803 free_extent_buffer(next);
5804 btrfs_release_path(path);
5809 btrfs_set_path_blocking(path);
5810 btrfs_tree_read_lock(next);
5811 btrfs_clear_path_blocking(path, next,
5814 next_rw_lock = BTRFS_READ_LOCK;
5818 path->slots[level] = slot;
5821 c = path->nodes[level];
5822 if (path->locks[level])
5823 btrfs_tree_unlock_rw(c, path->locks[level]);
5825 free_extent_buffer(c);
5826 path->nodes[level] = next;
5827 path->slots[level] = 0;
5828 if (!path->skip_locking)
5829 path->locks[level] = next_rw_lock;
5833 ret = read_block_for_search(root, path, &next, level,
5839 btrfs_release_path(path);
5843 if (!path->skip_locking) {
5844 ret = btrfs_try_tree_read_lock(next);
5846 btrfs_set_path_blocking(path);
5847 btrfs_tree_read_lock(next);
5848 btrfs_clear_path_blocking(path, next,
5851 next_rw_lock = BTRFS_READ_LOCK;
5856 unlock_up(path, 0, 1, 0, NULL);
5857 path->leave_spinning = old_spinning;
5859 btrfs_set_path_blocking(path);
5865 * this uses btrfs_prev_leaf to walk backwards in the tree, and keeps
5866 * searching until it gets past min_objectid or finds an item of 'type'
5868 * returns 0 if something is found, 1 if nothing was found and < 0 on error
5870 int btrfs_previous_item(struct btrfs_root *root,
5871 struct btrfs_path *path, u64 min_objectid,
5874 struct btrfs_key found_key;
5875 struct extent_buffer *leaf;
5880 if (path->slots[0] == 0) {
5881 btrfs_set_path_blocking(path);
5882 ret = btrfs_prev_leaf(root, path);
5888 leaf = path->nodes[0];
5889 nritems = btrfs_header_nritems(leaf);
5892 if (path->slots[0] == nritems)
5895 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5896 if (found_key.objectid < min_objectid)
5898 if (found_key.type == type)
5900 if (found_key.objectid == min_objectid &&
5901 found_key.type < type)
5908 * search in extent tree to find a previous Metadata/Data extent item with
5911 * returns 0 if something is found, 1 if nothing was found and < 0 on error
5913 int btrfs_previous_extent_item(struct btrfs_root *root,
5914 struct btrfs_path *path, u64 min_objectid)
5916 struct btrfs_key found_key;
5917 struct extent_buffer *leaf;
5922 if (path->slots[0] == 0) {
5923 btrfs_set_path_blocking(path);
5924 ret = btrfs_prev_leaf(root, path);
5930 leaf = path->nodes[0];
5931 nritems = btrfs_header_nritems(leaf);
5934 if (path->slots[0] == nritems)
5937 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5938 if (found_key.objectid < min_objectid)
5940 if (found_key.type == BTRFS_EXTENT_ITEM_KEY ||
5941 found_key.type == BTRFS_METADATA_ITEM_KEY)
5943 if (found_key.objectid == min_objectid &&
5944 found_key.type < BTRFS_EXTENT_ITEM_KEY)