ModelForm = self.get_form(request, obj, form=form)

        formsets = []
        if request.method == 'POST':
            # commit only when all forms are valid
            with transaction.commit_manually():
                try:
                    objects_count = 0
                    changed_count = 0
                    objects = queryset.all()
                    for obj in objects:
                        add_fields = []
                        old_values_to_add = {}
                        objects_count += 1
                        form = ModelForm(request.POST, request.FILES, instance=obj)

                        exclude = []
                        for fieldname, field in form.fields.items():
                            mass_change_checkbox = '_mass_change_%s' % fieldname
                            if not (request.POST.has_key(mass_change_checkbox) and request.POST[mass_change_checkbox] in ('on', 'set', 'add')):
                                exclude.append(fieldname)
                            if request.POST.has_key(mass_change_checkbox) and request.POST[mass_change_checkbox] in ('add',):
                                add_fields.append(fieldname)
                        for exclude_fieldname in exclude:
                            del form.fields[exclude_fieldname]

                        if form.is_valid():
                            form_validated = True
                            new_object = self.save_form(request, form, change=True)
                        else:
                            form_validated = False
                            new_object = obj
                        prefixes = {}
                        for FormSet in self.get_formsets(request, new_object):
                            prefix = FormSet.get_default_prefix()
                            prefixes[prefix] = prefixes.get(prefix, 0) + 1
                            if prefixes[prefix] != 1:
                                prefix = "%s-%s" % (prefix, prefixes[prefix])
                            mass_change_checkbox = '_mass_change_%s' % prefix
                            if request.POST.has_key(mass_change_checkbox) and request.POST[mass_change_checkbox] in ('on', 'set', 'add'):
                                formset = FormSet(request.POST, request.FILES, instance=new_object, prefix=prefix)
                                formsets.append(formset)
                        for field in add_fields:
                            old_values_to_add[field] = list(getattr(obj, field).all())
                        if all_valid(formsets) and form_validated:
                            self.save_model(request, new_object, form, change=True)
                            # self.save_model(request, new_object, form, change=True)
                            form.save_m2m()
                            for formset in formsets:
                                self.save_formset(request, form, formset, change=True)
                            for field, value in old_values_to_add.items():
                                for rel in value:
                                    getattr(obj, field).add(rel)

                            change_message = self.construct_change_message(request, form, formsets)
                            self.log_change(request, new_object, change_message)
                            changed_count += 1

                    if changed_count != objects_count:
                        raise Exception('Some of the selected objects could\'t be changed.')
                    transaction.commit()
                    return self.response_change(request, new_object)

                finally:
                    general_error = unicode(sys.exc_info()[1])
                    transaction.rollback()


        form = ModelForm()