[OVN] Bump revision number after update_virtual_port_host

This patch adds bump revision after updating the hostname
of a virtual port (more specifically its associated port).
This way there is no misalignment between the revision number
of Neutron DB and OVN DB.

It also avoids the unnecessary execution of the maintenance
task to simply match the revision_number.

Closes-Bug: #2069046
Change-Id: I2734984f10341ab97ebbdee11389d214bb1150f3
(cherry picked from commit f210a90)

Author: fernandoroyosanchez

neutron/plugins/ml2/drivers/ovn/mech_driver/mech_driver.py

@@ -1081,16 +1081,22 @@ def update_virtual_port_host(self, port_id, chassis_id):
             hostname = ''
 
         # Updates neutron database with hostname for virtual port
-        self._plugin.update_virtual_port_host(n_context.get_admin_context(),
-                                              port_id, hostname)
-
+        context = n_context.get_admin_context()
+        self._plugin.update_virtual_port_host(context, port_id, hostname)
+        db_port = self._plugin.get_port(context, port_id)
+        check_rev_cmd = self.nb_ovn.check_revision_number(
+            port_id, db_port, ovn_const.TYPE_PORTS)
         # Updates OVN NB database with hostname for lsp virtual port
         with self.nb_ovn.transaction(check_error=True) as txn:
             ext_ids = ('external_ids',
                        {ovn_const.OVN_HOST_ID_EXT_ID_KEY: hostname})
             txn.add(
                 self.nb_ovn.db_set(
                     'Logical_Switch_Port', port_id, ext_ids))
+            txn.add(check_rev_cmd)
+        if check_rev_cmd.result == ovn_const.TXN_COMMITTED:
+            ovn_revision_numbers_db.bump_revision(context, db_port,
+                                                  ovn_const.TYPE_PORTS)
 
     def get_workers(self):
         """Get any worker instances that should have their own process

neutron/tests/functional/plugins/ml2/drivers/ovn/mech_driver/ovsdb/test_ovsdb_monitor.py

@@ -450,6 +450,30 @@ def _check_port_host_set(self, port_id, host_id):
         # Check that both neutron and ovn are the same as given host_id
         return port[portbindings.HOST_ID] == host_id == ovn_host_id
 
+    def _check_port_and_port_binding_revision_number(self, port_id):
+
+        def is_port_and_port_binding_same_revision_number(port_id):
+            # This function checks if given port matches the revision_number
+            # in the neutron DB as well as in the OVN DB for the port_binding
+            core_plugin = directory.get_plugin()
+
+            # Get port from neutron DB
+            port = core_plugin.get_ports(
+                self.context, filters={'id': [port_id]})[0]
+
+            # Get port binding from OVN DB
+            bp = self._find_port_binding(port_id)
+            ovn_port_binding_revision_number = bp.external_ids.get(
+                ovn_const.OVN_REV_NUM_EXT_ID_KEY, ovn_const.INITIAL_REV_NUM)
+
+            # Check that both neutron and ovn are the same as given host_id
+            return port['revision_number'] == int(
+                ovn_port_binding_revision_number)
+
+        check = functools.partial(
+            is_port_and_port_binding_same_revision_number,port_id)
+        n_utils.wait_until_true(check, timeout=10)
+
     def test_virtual_port_host_update_upon_failover(self):
         # NOTE: we can't simulate traffic, but we can simulate the event that
         # would've been triggered by OVN, which is what we do.
@@ -469,6 +493,7 @@ def test_virtual_port_host_update_upon_failover(self):
         vip_address = vip['fixed_ips'][0]['ip_address']
         allowed_address_pairs = [{'ip_address': vip_address}]
         self._check_port_binding_type(vip['id'], '')
+        self._check_port_and_port_binding_revision_number(vip['id'])
 
         # 3) Create two ports with the allowed address pairs set.
         hosts = ('ovs-host1', second_chassis_name)
@@ -485,25 +510,29 @@ def test_virtual_port_host_update_upon_failover(self):
         # have been assigned to the port binding
         self._check_port_binding_type(vip['id'], ovn_const.LSP_TYPE_VIRTUAL)
         self._check_port_virtual_parents(vip['id'], ','.join(port_ids))
+        self._check_port_and_port_binding_revision_number(vip['id'])
 
         # 5) Bind the ports to a host, so a chassis is bound, which is
         # required for the update_virtual_port_host method. Without this
         # chassis set, it will not set a hostname in the DB's
         self._test_port_binding_and_status(ports[0]['id'], 'bind', 'ACTIVE')
         self.chassis = second_chassis
         self._test_port_binding_and_status(ports[1]['id'], 'bind', 'ACTIVE')
+        self._check_port_and_port_binding_revision_number(vip['id'])
 
         # 6) For both ports, bind vip on parent and check hostname in DBs
         for idx in range(len(ports)):
             # Set port binding to the first port, and update the chassis
             self._set_port_binding_virtual_parent(vip['id'], ports[idx]['id'])
+            self._check_port_and_port_binding_revision_number(vip['id'])
 
             # Check if the host_id has been updated in OVN and DB
             # by the event that eventually calls for method
             # OVNMechanismDriver.update_virtual_port_host
             n_utils.wait_until_true(
                 lambda: self._check_port_host_set(vip['id'], hosts[idx]),
                 timeout=10)
+            self._check_port_and_port_binding_revision_number(vip['id'])
 
 
 class TestNBDbMonitorOverTcp(TestNBDbMonitor):