HAMMER2_LBUFSIZE
io_base = io_off & ~(hammer2_off_t)(HAMMER2_LBUFSIZE - 1);
io_bytes = HAMMER2_LBUFSIZE;
#define HAMMER2_IND_BYTES_NOM HAMMER2_LBUFSIZE
#define HAMMER2_LBUFMASK (HAMMER2_LBUFSIZE - 1)