Btrfs: properly check free space for tree balancing

btrfs_insert_empty_items takes the space needed by the btrfs_item
structure into account when calculating the required free space.

So the tree balancing code shouldn't add sizeof(struct btrfs_item)
to the size when checking the free space. This patch removes these
superfluous additions.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>

1 files changed, 2 insertions, 7 deletions

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 6ac1b7f72e2a..33eee256ee81 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -374,13 +374,8 @@ insert:
                 if (found_size > item_size) {
                         btrfs_truncate_item(trans, root, path, item_size, 1);
                 } else if (found_size < item_size) {
-                        ret = btrfs_del_item(trans, root,
-                                             path);
-                        BUG_ON(ret);
-
-                        btrfs_release_path(root, path);
-                        ret = btrfs_insert_empty_item(trans,
-                                  root, path, key, item_size);
+                        ret = btrfs_extend_item(trans, root, path,
+                                                item_size - found_size);
                         BUG_ON(ret);
                 }
         } else if (ret) {