CEPH_FSCRYPT_AUTH_VERSION
as->fscrypt_auth->cfa_version = cpu_to_le32(CEPH_FSCRYPT_AUTH_VERSION);
if (le32_to_cpu(cfa->cfa_version) != CEPH_FSCRYPT_AUTH_VERSION)
cfa->cfa_version = cpu_to_le32(CEPH_FSCRYPT_AUTH_VERSION);