ovn-controller: Clear flow-restore-wait.

In commit 621f85e ("controller: Fix bfd up too early after
unexpected reboot."), OVN would manipulate the flow-restore-wait flag in
order to attempt to synchronize with OVS. The previous commit reverted
this change due to a potential deadlock between OVS and OVN.

If users were using a version of OVN that had commit 621f85e, then
the revert will help to ensure that OVS and OVN won't deadlock any
longer. However, the revert on its own does not resolve the deadlock if
the previously running version of ovn-controller set flow-restore-wait
to true. It requires manual intervention to get flow-restore-wait set to
false or deleted from the Open_vSwitch table.

This commit seeks to assist by clearing the flow-restore-wait key in the
Open_vSwitch table. This way, on upgrade, the deadlock is resolved
without manually setting any OVS database values.

Reported-at: https://redhat.atlassian.net/browse/FDP-3862
Fixes: 621f85e ("controller: Fix bfd up too early after unexpected reboot.")
Signed-off-by: Mark Michelson <mmichels@redhat.com>
Acked-by: Dumitru Ceara <dceara@redhat.com>
Signed-off-by: Ales Musil <amusil@redhat.com>
(cherry picked from commit 89dbc40)

Author: putnopvut

controller/ovn-controller.c

@@ -7554,6 +7554,24 @@ main(int argc, char *argv[])
                 ovsrec_open_vswitch_update_other_config_setkey(
                     cfg, "vlan-limit", "0");
             }
+            /* Clear flow-restore-wait. OVN at one point would set
+             * flow-restore-wait in order to try to synchronize with
+             * OVS. However, that resulted in a bug, so that behavior
+             * was reverted. If upgrading from a version where OVN
+             * manipulted flow-restore-wait, then flow-restore-wait
+             * needs to be cleared in order for OVS to function
+             * properly. This is (hopefully) a temporary measure until
+             * a more reliable method of synchronizing with OVS is
+             * devised.
+             */
+            if (smap_get_bool(&cfg->external_ids,
+                              "ovn-managed-flow-restore-wait", false) &&
+                smap_get(&cfg->other_config, "flow-restore-wait")) {
+                ovsrec_open_vswitch_update_other_config_delkey(
+                    cfg, "flow-restore-wait");
+                ovsrec_open_vswitch_update_external_ids_delkey(
+                   cfg, "ovn-managed-flow-restore-wait");
+            }
         }
 
         static bool chassis_idx_stored = false;