4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ilya Dryomov idryomov@gmail.com
commit 7b4c443d139f1d2b5570da475f7a9cbcef86740c upstream.
If we go without an established session for a while, backoff delay will climb to 30 seconds. The keepalive timeout is also 30 seconds, so it's pretty easily hit after a prolonged hunting for a monitor: we don't get a chance to send out a keepalive in time, which means we never get back a keepalive ack in time, cutting an established session and attempting to connect to a different monitor every 30 seconds:
[Sun Apr 1 23:37:05 2018] libceph: mon0 10.80.20.99:6789 session established [Sun Apr 1 23:37:36 2018] libceph: mon0 10.80.20.99:6789 session lost, hunting for new mon [Sun Apr 1 23:37:36 2018] libceph: mon2 10.80.20.103:6789 session established [Sun Apr 1 23:38:07 2018] libceph: mon2 10.80.20.103:6789 session lost, hunting for new mon [Sun Apr 1 23:38:07 2018] libceph: mon1 10.80.20.100:6789 session established [Sun Apr 1 23:38:37 2018] libceph: mon1 10.80.20.100:6789 session lost, hunting for new mon [Sun Apr 1 23:38:37 2018] libceph: mon2 10.80.20.103:6789 session established [Sun Apr 1 23:39:08 2018] libceph: mon2 10.80.20.103:6789 session lost, hunting for new mon
The regular keepalive interval is 10 seconds. After ->hunting is cleared in finish_hunting(), call __schedule_delayed() to ensure we send out a keepalive after 10 seconds.
Cc: stable@vger.kernel.org # 4.7+ Link: http://tracker.ceph.com/issues/23537 Signed-off-by: Ilya Dryomov idryomov@gmail.com Reviewed-by: Jason Dillaman dillaman@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/ceph/mon_client.c | 1 + 1 file changed, 1 insertion(+)
--- a/net/ceph/mon_client.c +++ b/net/ceph/mon_client.c @@ -1124,6 +1124,7 @@ static void finish_hunting(struct ceph_m monc->hunting = false; monc->had_a_connection = true; un_backoff(monc); + __schedule_delayed(monc); } }