int exfat_set_volume_serial(struct exfat_blk_dev *bd,
struct exfat_user_input *ui);
unsigned int exfat_clus_to_blk_dev_off(struct exfat_blk_dev *bd,
int exfat_set_volume_serial(struct exfat_blk_dev *bd,
struct exfat_user_input *ui);
unsigned int exfat_clus_to_blk_dev_off(struct exfat_blk_dev *bd,