ceph_fscrypt_auth_len
ci->fscrypt_auth_len = ceph_fscrypt_auth_len(as->fscrypt_auth);
u32 len = ceph_fscrypt_auth_len(cia->fscrypt_auth);
u32 authlen = ceph_fscrypt_auth_len(req->r_fscrypt_auth);
len += ceph_fscrypt_auth_len(req->r_fscrypt_auth);