logbtofrag
bp = getdatablk(logbtofrag(&sblock, sblock.fs_logbno),
fno = logbtofrag(&sblock, ep->pbno);
fno = logbtofrag(&sblock, sblock.fs_logbno);
fno = logbtofrag(fs, ep->pbno);
free(ip, logbtofrag(fs, logbno), fs->fs_bsize, 0);