libceph: flush msgr queue during mon_client shutdown

We need to flush the msgr workqueue during mon_client shutdown to
ensure that any work affecting our embedded ceph_connection is
finished so that we can be safely destroyed.

Previously, we were flushing the work queue after osd_client
shutdown and before mon_client shutdown to ensure that any osd
connection refs to authorizers are flushed.  Remove the redundant
flush, and document in the comment that the mon_client flush is
needed to cover that case as well.

Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/net/ceph/mon_client.c b/net/ceph/mon_client.c
index 7a16750d62a6..dc16595d6885 100644
--- a/net/ceph/mon_client.c
+++ b/net/ceph/mon_client.c
@@ -838,6 +838,14 @@ void ceph_monc_stop(struct ceph_mon_client *monc)
 
         mutex_unlock(&monc->mutex);
 
+        /*
+         * flush msgr queue before we destroy ourselves to ensure that:
+         *  - any work that references our embedded con is finished.
+         *  - any osd_client or other work that may reference an authorizer
+         *    finishes before we shut down the auth subsystem.
+         */
+        ceph_msgr_flush();
+
         ceph_auth_destroy(monc->auth);
 
         ceph_msg_put(monc->m_auth);