nfsd/callback: Cleanup callback cred on shutdown

The rpccred gotten from rpc_lookup_machine_cred() should be put when
state is shutdown.
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfs4callback.c

@@ -753,6 +753,14 @@ int set_callback_cred(void)
 	return 0;
 }
 
+void cleanup_callback_cred(void)
+{
+	if (callback_cred) {
+		put_rpccred(callback_cred);
+		callback_cred = NULL;
+	}
+}
+
 static struct rpc_cred *get_backchannel_cred(struct nfs4_client *clp, struct rpc_clnt *client, struct nfsd4_session *ses)
 {
 	if (clp->cl_minorversion == 0) {

fs/nfsd/nfs4state.c

@@ -7012,23 +7012,24 @@ nfs4_state_start(void)
 
 	ret = set_callback_cred();
 	if (ret)
-		return -ENOMEM;
+		return ret;
+
 	laundry_wq = alloc_workqueue("%s", WQ_UNBOUND, 0, "nfsd4");
 	if (laundry_wq == NULL) {
 		ret = -ENOMEM;
-		goto out_recovery;
+		goto out_cleanup_cred;
 	}
 	ret = nfsd4_create_callback_queue();
 	if (ret)
 		goto out_free_laundry;
 
 	set_max_delegations();
-
 	return 0;
 
 out_free_laundry:
 	destroy_workqueue(laundry_wq);
-out_recovery:
+out_cleanup_cred:
+	cleanup_callback_cred();
 	return ret;
 }
 
@@ -7086,6 +7087,7 @@ nfs4_state_shutdown(void)
 {
 	destroy_workqueue(laundry_wq);
 	nfsd4_destroy_callback_queue();
+	cleanup_callback_cred();
 }
 
 static void

fs/nfsd/state.h

@@ -615,6 +615,7 @@ extern struct nfs4_client_reclaim *nfsd4_find_reclaim_client(const char *recdir,
 extern __be32 nfs4_check_open_reclaim(clientid_t *clid,
 		struct nfsd4_compound_state *cstate, struct nfsd_net *nn);
 extern int set_callback_cred(void);
+extern void cleanup_callback_cred(void);
 extern void nfsd4_probe_callback(struct nfs4_client *clp);
 extern void nfsd4_probe_callback_sync(struct nfs4_client *clp);
 extern void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *);