static int
nvs_operation(nvstream_t *nvs, nvlist_t *nvl, size_t *buflen)
{
	int err;

	if (nvl->nvl_priv == 0)
		return (EFAULT);

	/*
	 * Perform the operation, starting with header, then each nvpair
	 */
	if ((err = nvs->nvs_ops->nvs_nvlist(nvs, nvl, buflen)) != 0)
		return (err);

	switch (nvs->nvs_op) {
	case NVS_OP_ENCODE:
		err = nvs_encode_pairs(nvs, nvl);
		break;

	case NVS_OP_DECODE:
		err = nvs_decode_pairs(nvs, nvl);
		break;

	case NVS_OP_GETSIZE:
		err = nvs_getsize_pairs(nvs, nvl, buflen);
		break;

	default:
		err = EINVAL;
	}

	return (err);
}