ioget
static int ioget(struct open_file *, u_int, void *, u_int);
(err = ioget(fs->fd, 0, fs->buf, 1)) ||
if ((err = ioget(fs->fd, lsec + sec, dir, 1)))
if ((err = ioget(fs->fd, bytsec(offset), s, bytsec(nbyte))))
if ((err = ioget(fs->fd, lsec, fs->buf, 1)))