DL_BLKSPERSEC
ns = disk.dk_bootprt.prt_ns + DL_BLKSPERSEC(&dl) - 1;
bs = disk.dk_bootprt.prt_bs + DL_BLKSPERSEC(&dl) - 1;
if ((bp->b_blkno % DL_BLKSPERSEC(lp)) != 0 ||
if ((blkno % DL_BLKSPERSEC(lp)) != 0)
#define DL_SECTOBLK(d, n) ((n) * DL_BLKSPERSEC(d))
#define DL_BLKTOSEC(d, n) ((n) / DL_BLKSPERSEC(d))
#define DL_BLKOFFSET(d, n) (((n) % DL_BLKSPERSEC(d)) * DEV_BSIZE)