xlog_cksum
iclog->ic_header->h_crc = xlog_cksum(log, iclog->ic_header,
__le32 xlog_cksum(struct xlog *log, struct xlog_rec_header *rhead,
crc = xlog_cksum(log, rhead, dp, XLOG_REC_SIZE,
other_crc = xlog_cksum(log, rhead, dp, XLOG_REC_SIZE_OTHER,