blkptrtodb
*bnp = blkptrtodb(ump, letoh32(ip->i_e2fs_blocks[bn]));
bp->b_blkno = blkptrtodb(ump, daddr);
daddr = blkptrtodb(ump, daddr);
*bnp = blkptrtodb(ump, DIP(ip, db[bn]));
bp->b_blkno = blkptrtodb(ump, daddr);
daddr = blkptrtodb(ump, daddr);