AFFS_CACHE_SIZE
#define AFFS_LC_SIZE (AFFS_CACHE_SIZE/sizeof(u32)/2)
#define AFFS_AC_SIZE (AFFS_CACHE_SIZE/sizeof(struct affs_ext_key)/2)
AFFS_I(inode)->i_ac = (struct affs_ext_key *)(ptr + AFFS_CACHE_SIZE / 2);