DENTRY_SIZE_BITS
off = es->start_off + (i << DENTRY_SIZE_BITS);
bh->b_blocknr, off >> DENTRY_SIZE_BITS, ep->type);
#define EXFAT_B_TO_DEN(b) ((b) >> DENTRY_SIZE_BITS)
#define EXFAT_DEN_TO_B(b) ((b) << DENTRY_SIZE_BITS)
((clu) << ((sbi)->cluster_size_bits - DENTRY_SIZE_BITS))
((dentry) >> ((sbi)->cluster_size_bits - DENTRY_SIZE_BITS))
(sbi->cluster_size_bits - DENTRY_SIZE_BITS);