ovsdb-idl.c: Clear conditions when clearing IDL.

If the ovsdb-server reply to "monitor_cond_since" requests has
"found" == false then ovsdb_idl_db_parse_monitor_reply() calls
ovsdb_idl_db_clear() which iterates through all tables and
unconditionally sets table->cond_changed to false.

However, if the client had already set a new condition for some of the
tables, this new condition request will never be sent to ovsdb-server
until the condition is reset to a different value. This is due to the
check in ovsdb_idl_db_set_condition().

In order to fix this we now also call ovsdb_idl_condition_clear() for
each table condition in ovsdb_idl_db_clear(). This ensures that
resetting the condition to the same value as before the
"monitor_cond_since" reply will trigger a new request.

One way to replicate the issue is described in the bugzilla reporting
the bug, when ovn-controller is configured to use "ovn-monitor-all":
https://bugzilla.redhat.com/show_bug.cgi?id=1808125#c6

Reported-by: Dan Williams <dcbw@redhat.com>
Reported-at: https://bugzilla.redhat.com/1808125
CC: Han Zhou <hzhou@ovn.org>
Fixes: 403a6a0 ("ovsdb-idl: Fast resync from server when connection reset.")
Signed-off-by: Dumitru Ceara <dceara@redhat.com>
Signed-off-by: 0-day Robot <robot@bytheb.org>

lib/ovsdb-idl.c

@@ -610,7 +610,11 @@ ovsdb_idl_db_clear(struct ovsdb_idl_db *db)
         struct ovsdb_idl_table *table = &db->tables[i];
         struct ovsdb_idl_row *row, *next_row;
 
-        table->cond_changed = false;
+        if (table->cond_changed) {
+            table->cond_changed = false;
+            ovsdb_idl_condition_clear(&table->condition);
+        }
+
         if (hmap_is_empty(&table->rows)) {
             continue;
         }