wp_save_post_type.php

<?php

	add_action( 'save_post', array($self, 'save_custom_fields'), 10, 3 );
	function save_custom_fields( $post_id, $post, $update) {
		if ( $post->post_type != 'pfm_registration' ) {
			return false;
		}

		if ( empty( $_POST['data'] ) ) {
			return false;
		}

		update_post_meta( $post_id, 'pfm_registration_fields',$_POST['data'] );

		if ( !empty( $_POST['notification'] ) ) {
			update_post_meta( $post_id, 'pfm_notification_fields',$_POST['notification'] );
		}

		if ( !empty( $_POST['user_redirect'] ) ) {
			update_post_meta( $post_id, 'pfm_user_redirect_fields',$_POST['user_redirect'] );
		}


		$data = $_POST['data'];
		$previous_metas = get_option('pfm_metadata');

		if (empty($previous_metas)) {
			return false;
		}

		foreach($data as $arr)
		{
		    foreach($arr as $key => $val){
		        if ($key == "metadata" && !empty($val) && !in_array($val, $previous_metas) ) {
				    $previous_metas[] = $val;
			    	update_option( 'pfm_metadata', $previous_metas);
			    }
		    }
		}
	}