From 25e65df7974c238517ab51ea07079ab0482ad44a Mon Sep 17 00:00:00 2001
From: Brian Haley <brian.haley@hpe.com>
Date: Wed, 14 Sep 2016 16:52:07 -0400
Subject: [PATCH] Fix migration of legacy router to DVR

We have to ensure ML2's create_port method is not called
in a transaction.

This adds a temporary hack to set an attribute on the context
to skip this check to accomodate an L3 code-path that has a port
creation entangled in a transaction.  This attribute will
ultimately be removed once this path is refactored.

Change-Id: I9c41a7848b22c437bedcdd7eb57f7c9da873b06d
Closes-bug: #1619312
---
 neutron/db/l3_dvr_db.py                       |  2 ++
 .../l3_router/test_l3_dvr_router_plugin.py    | 35 +++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/neutron/db/l3_dvr_db.py b/neutron/db/l3_dvr_db.py
index 32f9d9b11d0..39d8f3925ab 100644
--- a/neutron/db/l3_dvr_db.py
+++ b/neutron/db/l3_dvr_db.py
@@ -139,6 +139,8 @@ class L3_NAT_with_dvr_db_mixin(l3_db.L3_NAT_db_mixin,
                     # router, make sure to create corresponding
                     # snat interface ports that are to be consumed by
                     # the Service Node.
+                    # TODO(haleyb): move this out of transaction
+                    setattr(context, 'GUARD_TRANSACTION', False)
                     if not self._create_snat_intf_ports_if_not_exists(
                         context.elevated(), router_db):
                         LOG.debug("SNAT interface ports not created: %s",
diff --git a/neutron/tests/functional/services/l3_router/test_l3_dvr_router_plugin.py b/neutron/tests/functional/services/l3_router/test_l3_dvr_router_plugin.py
index ea650287b10..912abb88207 100644
--- a/neutron/tests/functional/services/l3_router/test_l3_dvr_router_plugin.py
+++ b/neutron/tests/functional/services/l3_router/test_l3_dvr_router_plugin.py
@@ -1532,3 +1532,38 @@ class L3DvrTestCase(ml2_test_base.ML2TestFramework):
             self.context, router['id'])
         self.assertEqual(1, len(agents['agents']))
         self.assertEqual(self.l3_agent['id'], agents['agents'][0]['id'])
+
+
+class L3DvrTestCaseMigration(L3DvrTestCase):
+    def test_update_router_db_centralized_to_distributed_with_ports(self):
+        with self.subnet() as subnet1:
+            kwargs = {'arg_list': (external_net.EXTERNAL,),
+                      external_net.EXTERNAL: True}
+            with self.network(**kwargs) as ext_net, \
+                    self.subnet(network=ext_net,
+                                cidr='30.0.0.0/24'):
+                router = self._create_router(distributed=False)
+                self.l3_plugin.add_router_interface(
+                    self.context, router['id'],
+                    {'subnet_id': subnet1['subnet']['id']})
+                self.l3_plugin._update_router_gw_info(
+                    self.context, router['id'],
+                    {'network_id': ext_net['network']['id']})
+                self.assertEqual(
+                    0, len(self.l3_plugin._get_snat_sync_interfaces(
+                        self.context, [router['id']])))
+
+                # router needs to be in admin state down in order to be
+                # upgraded to DVR
+                self.l3_plugin.update_router(
+                    self.context, router['id'],
+                    {'router': {'admin_state_up': False}})
+                self.assertFalse(router['distributed'])
+                self.l3_plugin.update_router(
+                    self.context, router['id'],
+                    {'router': {'distributed': True}})
+                router = self.l3_plugin.get_router(self.context, router['id'])
+                self.assertTrue(router['distributed'])
+                self.assertEqual(
+                    1, len(self.l3_plugin._get_snat_sync_interfaces(
+                        self.context, [router['id']])))