Add this method to your django model to quickly retrieve every object that links to it.

used_in.py

    def used_in(self):
        """
        Method to return all objects where this object is linked from by
        a foreign key or many-to-many relationship

        Be aware that:
        - Calling this method wil result in as many queries as there are 
          relations, so use this carefully.
        - It will only see the models linking directly to this model. So watch
          out for inherited models. Calling used_in on a childobject will
          return 0 objects when a field will link to the parentobject

        :return: mixed list of django model instances
        """
        object_list = []
        for relation_field in self._meta._relation_tree:
            kwargs = {relation_field.name: self.pk}
            object_list.extend(relation_field.model.objects.filter(**kwargs))
        return object_list