ovsdb: Make OVSDB backup sever read only

When ovsdb-sever is running in the backup state, it would be nice to
make sure there is no un-intended changes to the backup database.

This patch makes the ovsdb server only accepts 'read' transactions as
a backup server. When the server role is changed into an active server,
all existing client connections will be reset. After reconnect, all
clinet transactions will then be accepted.

Signed-off-by: Andy Zhou <azhou@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>

1 files changed, 5 insertions, 2 deletions

diff --git a/ovsdb/trigger.c b/ovsdb/trigger.c
index 0fbe94908..a859983f4 100644
--- a/ovsdb/trigger.c
+++ b/ovsdb/trigger.c
@@ -31,7 +31,8 @@ static void ovsdb_trigger_complete(struct ovsdb_trigger *);
 void
 ovsdb_trigger_init(struct ovsdb_session *session, struct ovsdb *db,
                    struct ovsdb_trigger *trigger,
-                   struct json *request, long long int now)
+                   struct json *request, long long int now,
+                   bool read_only)
 {
     trigger->session = session;
     trigger->db = db;
@@ -40,6 +41,7 @@ ovsdb_trigger_init(struct ovsdb_session *session, struct ovsdb *db,
     trigger->result = NULL;
     trigger->created = now;
     trigger->timeout_msec = LLONG_MAX;
+    trigger->read_only = read_only;
     ovsdb_trigger_try(trigger, now);
 }
 
@@ -111,7 +113,8 @@ static bool
 ovsdb_trigger_try(struct ovsdb_trigger *t, long long int now)
 {
     t->result = ovsdb_execute(t->db, t->session,
-                              t->request, now - t->created, &t->timeout_msec);
+                              t->request, t->read_only,
+                              now - t->created, &t->timeout_msec);
     if (t->result) {
         ovsdb_trigger_complete(t);
         return true;