Btrfs: fix wrong mtime and ctime when creating snapshots

When we created a new snapshot, the mtime and ctime of its parent directory
were not updated. Fix it.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

fs/btrfs/transaction.c

@@ -1026,6 +1026,7 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
 
 	btrfs_i_size_write(parent_inode, parent_inode->i_size +
 					 dentry->d_name.len * 2);
+	parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
 	ret = btrfs_update_inode(trans, parent_root, parent_inode);
 	if (ret)
 		goto abort_trans_dput;