read_one_tuplelist
last_tl = tlist = read_one_tuplelist(fd, MDF_ATTR, (off_t) 0);
tl = read_one_tuplelist(fd, flag, offs);
tlist->next = read_one_tuplelist(fd, 0, 0);
static struct tuple_list *read_one_tuplelist(int, int, off_t);