tag revision number

gistfile1.txt

diff --git a/neutron/db/models/tag.py b/neutron/db/models/tag.py
index 6fb7a36..42ef18b 100644
--- a/neutron/db/models/tag.py
+++ b/neutron/db/models/tag.py
@@ -28,3 +28,5 @@ class Tag(model_base.BASEV2):
     standard_attr = orm.relationship(
         'StandardAttribute',
         backref=orm.backref('tags', lazy='joined', viewonly=True))
+    revises_on_change = ('resource', )
+    resource = None
diff --git a/neutron/services/tag/tag_plugin.py b/neutron/services/tag/tag_plugin.py
index 4164e82..18f38a0 100644
--- a/neutron/services/tag/tag_plugin.py
+++ b/neutron/services/tag/tag_plugin.py
@@ -83,10 +83,12 @@ class TagPlugin(common_db_mixin.CommonDbMixin, tag_ext.TagPluginBase):
         with context.session.begin(subtransactions=True):
             for tag_db in res.standard_attr.tags:
                 if tag_db.tag in tags_removed:
+                    tag_db.resource = res
                     context.session.delete(tag_db)
             for tag in tags_added:
                 tag_db = tag_model.Tag(standard_attr_id=res.standard_attr_id,
                                        tag=tag)
+                tag_db.resource = res
                 context.session.add(tag_db)
         return body
 
@@ -99,6 +101,7 @@ class TagPlugin(common_db_mixin.CommonDbMixin, tag_ext.TagPluginBase):
             with context.session.begin(subtransactions=True):
                 tag_db = tag_model.Tag(standard_attr_id=res.standard_attr_id,
                                        tag=tag)
+                tag_db.resource = res
                 context.session.add(tag_db)
         except db_exc.DBDuplicateEntry:
             pass
@@ -109,7 +112,9 @@ class TagPlugin(common_db_mixin.CommonDbMixin, tag_ext.TagPluginBase):
         with context.session.begin(subtransactions=True):
             query = context.session.query(tag_model.Tag)
             query = query.filter_by(standard_attr_id=res.standard_attr_id)
-            query.delete()
+            for tag_db in query.all():
+                tag_db.resource = res
+                context.session.delete(tag_db)
 
     @log_helpers.log_method_call
     def delete_tag(self, context, resource, resource_id, tag):
@@ -118,8 +123,11 @@ class TagPlugin(common_db_mixin.CommonDbMixin, tag_ext.TagPluginBase):
             query = context.session.query(tag_model.Tag)
             query = query.filter_by(tag=tag,
                                     standard_attr_id=res.standard_attr_id)
-            if not query.delete():
+            tag_db = query.first()
+            if not tag_db:
                 raise tag_ext.TagNotFound(tag=tag)
+            tag_db.resource = res
+            context.session.delete(tag_db)
 
     # support only _apply_dict_extend_functions supported resources
     # at the moment.