BIOCVOL
if (ioctl(bt->fd, BIOCVOL, bv) == -1)
rv = ioctl(fd, BIOCVOL, &bv);
error = (*delegate)(cookie, BIOCVOL, bv);
case BIOCVOL:
case BIOCVOL:
case BIOCVOL:
case BIOCVOL:
case BIOCVOL:
case BIOCVOL:
case BIOCVOL:
case BIOCVOL:
case BIOCVOL:
case BIOCVOL: