vfs: get_sb_single() - do not pass options twice

Filesystem code usually destroys the option buffer while
parsing it. This leads to errors when the same buffer is
passed twice. In case we fill a new superblock do not call
remount.

This is needed to quite a warning that the debugfs code
causes every boot.

Cc: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

fs/super.c

@@ -901,8 +901,9 @@ int get_sb_single(struct file_system_type *fs_type,
 			return error;
 		}
 		s->s_flags |= MS_ACTIVE;
+	} else {
+		do_remount_sb(s, flags, data, 0);
 	}
-	do_remount_sb(s, flags, data, 0);
 	simple_set_mnt(mnt, s);
 	return 0;
 }