[patch 03/16] Return -ENOSYS for RPC programs that are unavailable

[Andreas Gruenbacher]

The issuer of an RPC call should be able to tell the difference between
an I/O error and program unavailable / program version unavailable /
procedure unavailable.  Return -ENOSYS for unavailable RPCs instead of
-EIO.

Only issue a program unavailable warning for program numbers other than
the one for nfsacl: Clients with nfsacl support are quite common
already; no need to clutter the syslog.

Signed-off-by: Andreas Gruenbacher <agruen@xxxxxxx>

Index: linux-2.6.11-rc5/net/sunrpc/clnt.c
===================================================================
--- linux-2.6.11-rc5.orig/net/sunrpc/clnt.c
+++ linux-2.6.11-rc5/net/sunrpc/clnt.c
@@ -970,6 +970,7 @@ call_verify(struct rpc_task *task)
 	struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
 	int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
 	u32	*p = iov->iov_base, n;
+	int error = -EACCES;
 
 	if ((len -= 3) < 0)
 		goto garbage;
@@ -980,8 +981,6 @@ call_verify(struct rpc_task *task)
 		goto garbage;
 	}
 	if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
-		int	error = -EACCES;
-
 		if (--len < 0)
 			goto garbage;
 		if ((n = ntohl(*p++)) != RPC_AUTH_ERROR) {
@@ -1035,23 +1034,26 @@ call_verify(struct rpc_task *task)
 	case RPC_SUCCESS:
 		return p;
 	case RPC_PROG_UNAVAIL:
-		printk(KERN_WARNING "RPC: call_verify: program %u is unsupported by server %s\n",
-				(unsigned int)task->tk_client->cl_prog,
-				task->tk_client->cl_server);
-		goto out_eio;
+		dprintk(KERN_WARNING "RPC: call_verify: program %u is unsupported by server %s\n",
+			(unsigned int)task->tk_client->cl_prog,
+			task->tk_client->cl_server);
+		error = -ENOSYS;
+		goto out_err;
 	case RPC_PROG_MISMATCH:
 		printk(KERN_WARNING "RPC: call_verify: program %u, version %u unsupported by server %s\n",
 				(unsigned int)task->tk_client->cl_prog,
 				(unsigned int)task->tk_client->cl_vers,
 				task->tk_client->cl_server);
-		goto out_eio;
+		error = -ENOSYS;
+		goto out_err;
 	case RPC_PROC_UNAVAIL:
 		printk(KERN_WARNING "RPC: call_verify: proc %p unsupported by program %u, version %u on server %s\n",
 				task->tk_msg.rpc_proc,
 				task->tk_client->cl_prog,
 				task->tk_client->cl_vers,
 				task->tk_client->cl_server);
-		goto out_eio;
+		error = -EOPNOTSUPP;
+		goto out_err;
 	case RPC_GARBAGE_ARGS:
 		break;			/* retry */
 	default:
@@ -1069,7 +1071,8 @@ garbage:
 		return NULL;
 	}
 	printk(KERN_WARNING "RPC: garbage, exit EIO\n");
-out_eio:
-	rpc_exit(task, -EIO);
+	error = -EIO;
+out_err:
+	rpc_exit(task, error);
 	return NULL;
 }

--
Andreas Gruenbacher <agruen@xxxxxxx>
SUSE Labs, SUSE LINUX PRODUCTS GMBH

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