rem: return EINVAL;
add: return FS_EINVAL;
context: do_ioctl(int argc, char **argv){	int fd;	int err;	if (argc < 2) {		printf("ioctl: too few arguments\n");		return EINVAL;	}	if ((fd = sys_open(1, -1, "/myfs/.", O_RDONLY, S_IFREG, 0)) < 0) {	    printf("ioctl: error opening '.'\n");	    return fd;	}	err = sys_ioctl(1, fd, atoi(argv[1]), 0, 0);	if (err < 0) {	    printf("ioctl: error!\n");	}	sys_close(1, fd);	return err;}