diff --git a/nova/api/openstack/compute/server_groups.py b/nova/api/openstack/compute/server_groups.py
index 4129122..a134477 100644
--- a/nova/api/openstack/compute/server_groups.py
+++ b/nova/api/openstack/compute/server_groups.py
@@ -27,7 +27,6 @@ from nova.api.openstack import wsgi
 from nova.api import validation
 import nova.exception
 from nova.i18n import _
-from nova.i18n import _LE
 from nova import objects
 from nova.policies import server_groups as sg_policies

@@ -91,29 +90,11 @@ class ServerGroupController(wsgi.Controller):
             sg = objects.InstanceGroup.get_by_uuid(context, id)
         except nova.exception.InstanceGroupNotFound as e:
             raise webob.exc.HTTPNotFound(explanation=e.format_message())
-
-        quotas = objects.Quotas(context=context)
-        project_id, user_id = objects.quotas.ids_from_server_group(context, sg)
-        try:
-            # We have to add the quota back to the user that created
-            # the server group
-            quotas.reserve(project_id=project_id,
-                           user_id=user_id, server_groups=-1)
-        except Exception:
-            quotas = None
-            LOG.exception(_LE("Failed to update usages deallocating "
-                                  "server group"))
-
         try:
             sg.destroy()
         except nova.exception.InstanceGroupNotFound as e:
-            if quotas:
-                quotas.rollback()
             raise webob.exc.HTTPNotFound(explanation=e.format_message())

-        if quotas:
-            quotas.commit()
-
     @extensions.expected_errors(())
     def index(self, req):
         """Returns a list of server groups."""
@@ -137,10 +118,10 @@ class ServerGroupController(wsgi.Controller):
         """Creates a new server group."""
         context = _authorize_context(req, 'create')

-        quotas = objects.Quotas(context=context)
         try:
-            quotas.reserve(project_id=context.project_id,
-                           user_id=context.user_id, server_groups=1)
+            objects.Quotas.check_deltas(context, 'server_groups',
+                                        {'server_groups': 1},
+                                        context.project_id, context.user_id)
         except nova.exception.OverQuota:
             msg = _("Quota exceeded, too many server groups.")
             raise exc.HTTPForbidden(explanation=msg)
@@ -154,10 +135,20 @@ class ServerGroupController(wsgi.Controller):
             sg.policies = vals.get('policies')
             sg.create()
         except ValueError as e:
-            quotas.rollback()
             raise exc.HTTPBadRequest(explanation=e)

-        quotas.commit()
+        # NOTE(melwitt): We recheck the quota after creating the
+        # object to handle races. Delete the object if we're over
+        # quota after creating the object.
+        try:
+            objects.Quotas.check_deltas(context, 'server_groups',
+                                        {'server_groups': 0},
+                                        context.project_id, context.user_id)
+        except nova.exception.OverQuota:
+            sg.destroy()
+            msg = _("Quota exceeded, too many server groups.")
+            raise exc.HTTPForbidden(explanation=msg)
+
         return {'server_group': self._format_server_group(context, sg, req)}