add: printf("init_cache_for_device(%d, %lld)\n", fd, max_blocks);
context: init_cache_for_device(int fd, fs_off_t max_blocks){    int ret = 0;        if (fd >= MAX_DEVICES)        return -1;    LOCK(bc.lock);    if (max_device_blocks[fd] != 0) {        printf("device %d is already initialized!\n", fd);        ret = -1;    } else {        max_device_blocks[fd] = max_blocks;    }    UNLOCK(bc.lock);    return ret;}