nfs client: exit_net cleanup check added

Be sure that nfs_client_list and nfs_volume_list lists initialized
in net_init hook were return to initial state in net_exit hook.
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/inode.c

@@ -2084,8 +2084,12 @@ static int nfs_net_init(struct net *net)
 
 static void nfs_net_exit(struct net *net)
 {
+	struct nfs_net *nn = net_generic(net, nfs_net_id);
+
 	nfs_fs_proc_net_exit(net);
 	nfs_cleanup_cb_ident_idr(net);
+	WARN_ON_ONCE(!list_empty(&nn->nfs_client_list));
+	WARN_ON_ONCE(!list_empty(&nn->nfs_volume_list));
 }
 
 static struct pernet_operations nfs_net_ops = {