nfs: handle NFSv2 -EKEYEXPIRED returns from RPC layer appropriately

Add a wrapper around rpc_call_sync that handles -EKEYEXPIRED errors from
the RPC layer as it would an -EJUKEBOX error if NFSv2 had such a thing.
Also, add a handler for that error for async calls that makes it
resubmit the RPC on -EKEYEXPIRED.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/proc.c

@@ -46,6 +46,39 @@
 
 #define NFSDBG_FACILITY		NFSDBG_PROC
 
+/*
+ * wrapper to handle the -EKEYEXPIRED error message. This should generally
+ * only happen if using krb5 auth and a user's TGT expires. NFSv2 doesn't
+ * support the NFSERR_JUKEBOX error code, but we handle this situation in the
+ * same way that we handle that error with NFSv3.
+ */
+static int
+nfs_rpc_wrapper(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
+{
+	int res;
+	do {
+		res = rpc_call_sync(clnt, msg, flags);
+		if (res != -EKEYEXPIRED)
+			break;
+		schedule_timeout_killable(NFS_JUKEBOX_RETRY_TIME);
+		res = -ERESTARTSYS;
+	} while (!fatal_signal_pending(current));
+	return res;
+}
+
+#define rpc_call_sync(clnt, msg, flags)	nfs_rpc_wrapper(clnt, msg, flags)
+
+static int
+nfs_async_handle_expired_key(struct rpc_task *task)
+{
+	if (task->tk_status != -EKEYEXPIRED)
+		return 0;
+	task->tk_status = 0;
+	rpc_restart_call(task);
+	rpc_delay(task, NFS_JUKEBOX_RETRY_TIME);
+	return 1;
+}
+
 /*
  * Bare-bones access to getattr: this is for nfs_read_super.
  */
@@ -307,6 +340,8 @@ nfs_proc_unlink_setup(struct rpc_message *msg, struct inode *dir)
 
 static int nfs_proc_unlink_done(struct rpc_task *task, struct inode *dir)
 {
+	if (nfs_async_handle_expired_key(task))
+		return 0;
 	nfs_mark_for_revalidate(dir);
 	return 1;
 }
@@ -560,6 +595,9 @@ nfs_proc_pathconf(struct nfs_server *server, struct nfs_fh *fhandle,
 
 static int nfs_read_done(struct rpc_task *task, struct nfs_read_data *data)
 {
+	if (nfs_async_handle_expired_key(task))
+		return -EAGAIN;
+
 	nfs_invalidate_atime(data->inode);
 	if (task->tk_status >= 0) {
 		nfs_refresh_inode(data->inode, data->res.fattr);
@@ -579,6 +617,9 @@ static void nfs_proc_read_setup(struct nfs_read_data *data, struct rpc_message *
 
 static int nfs_write_done(struct rpc_task *task, struct nfs_write_data *data)
 {
+	if (nfs_async_handle_expired_key(task))
+		return -EAGAIN;
+
 	if (task->tk_status >= 0)
 		nfs_post_op_update_inode_force_wcc(data->inode, data->res.fattr);
 	return 0;