ceph: close out mds, osd connections before stopping auth

The auth module (part of the mon_client) is needed to free any
ceph_authorizer(s) used by the mds and osd connections.  Flush the msgr
workqueue before stopping monc to ensure that the destroy_authorizer
auth op is available when those connections are closed out.

Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/messenger.c b/fs/ceph/messenger.c
index 60b7483..64b8b1f 100644
--- a/fs/ceph/messenger.c
+++ b/fs/ceph/messenger.c
@@ -120,6 +120,12 @@
 	destroy_workqueue(ceph_msgr_wq);
 }
 
+void ceph_msgr_flush()
+{
+	flush_workqueue(ceph_msgr_wq);
+}
+
+
 /*
  * socket callback functions
  */
diff --git a/fs/ceph/messenger.h b/fs/ceph/messenger.h
index 00a9430..76fbc95 100644
--- a/fs/ceph/messenger.h
+++ b/fs/ceph/messenger.h
@@ -213,6 +213,7 @@
 
 extern int ceph_msgr_init(void);
 extern void ceph_msgr_exit(void);
+extern void ceph_msgr_flush(void);
 
 extern struct ceph_messenger *ceph_messenger_create(
 	struct ceph_entity_addr *myaddr);
diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index 9b46bb9..5cf6fba 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -669,9 +669,17 @@
 
 	/* unmount */
 	ceph_mdsc_stop(&client->mdsc);
-	ceph_monc_stop(&client->monc);
 	ceph_osdc_stop(&client->osdc);
 
+	/*
+	 * make sure mds and osd connections close out before destroying
+	 * the auth module, which is needed to free those connections'
+	 * ceph_authorizers.
+	 */
+	ceph_msgr_flush();
+
+	ceph_monc_stop(&client->monc);
+
 	ceph_adjust_min_caps(-client->min_caps);
 
 	ceph_debugfs_client_cleanup(client);