ovl: root: copy attr

We copy i_uid and i_gid of underlying inode into overlayfs inode.  Except
for the root inode.

Fix this omission.
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Cc: <stable@vger.kernel.org>

fs/overlayfs/super.c

@@ -1079,6 +1079,9 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 
 	root_dentry->d_fsdata = oe;
 
+	ovl_copyattr(ovl_dentry_real(root_dentry)->d_inode,
+		     root_dentry->d_inode);
+
 	sb->s_magic = OVERLAYFS_SUPER_MAGIC;
 	sb->s_op = &ovl_super_operations;
 	sb->s_root = root_dentry;