btrfs: fix not enough reserved space

btrfs_link() will insert 3 items(inode ref, dir name item and dir index item)
into the b+ tree and update 2 items(its inode, and parent's inode) in the b+
tree. So we should reserve space for these 5 items, not 3 items.

Reported-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index e7a8303328b2..db67821ccac2 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4823,10 +4823,11 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
                 goto fail;
 
         /*
-         * 1 item for inode ref
+         * 2 items for inode and inode ref
          * 2 items for dir items
+         * 1 item for parent inode
          */
-        trans = btrfs_start_transaction(root, 3);
+        trans = btrfs_start_transaction(root, 5);
         if (IS_ERR(trans)) {
                 err = PTR_ERR(trans);
                 goto fail;