以下是对wp-admin 这应该可以做到：

/**
 * Modification of the wp-admin main (post) query: 
 *     If current user has the "client" role then 
 *     show client\'s posts OR posts where the "client" meta value is the client id.
 *
 * @see http://wordpress.stackexchange.com/a/173967/26350
 */

function wpse_pre_get_posts( $q )
{
    if( is_admin()
        && $q->is_main_query()
        && \'post\' === $q->get( \'post_type\' ) 
        && ! current_user_can( \'administrator\' )  
    ) 
    {
        $q->set( \'author\',  get_current_user_id() );
        if( current_user_can( \'client\' ) ) 
        {
            $q->set( \'author\',  null );
            $q->set( \'meta_key\', \'client\' );
            $q->set( \'meta_value\', get_current_user_id() );
            add_filter( \'posts_where\', \'wpse_posts_where\' );
        }
    }
    return $query;
}
add_filter( \'pre_get_posts\', \'wpse_pre_get_posts\' );

function wpse_posts_where( $where )
{
    global $wpdb;
    remove_filter( current_filter(), __FUNCTION__ );
    return str_ireplace(
        "{$wpdb->postmeta}.meta_key",
        sprintf( 
            "{$wpdb->posts}.post_author = %d 
             OR {$wpdb->postmeta}.meta_key", 
            get_current_user_id() 
        ),
        $where
    );
}