EXFAT_DATA_CLUSTER_COUNT
unsigned int total_clus = EXFAT_DATA_CLUSTER_COUNT(sbi);
need_map_size = ((EXFAT_DATA_CLUSTER_COUNT(sbi) - 1) / BITS_PER_BYTE)
if (unlikely(++clu_count > EXFAT_DATA_CLUSTER_COUNT(sbi)))
total_cnt = EXFAT_DATA_CLUSTER_COUNT(sbi);
if (unlikely(++clu_count > EXFAT_DATA_CLUSTER_COUNT(sbi)))