[PATCH] nfs: add $global.net.nfsport override

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Since commit 3ea30d9ce892 ("nfs: parse nfsport and mount port from file
system options"), it's possible to hard code the ports used for NFS,
which is especially useful when talking to a non-kernel NFS daemon
like unfsd.

Add a way to change the NFS port for the /mnt/nfs automount automount to
make this feature more accessible.

A simple one-time configuration can now look like this:

  $ nv user=afa
  $ nv net.server=mydevmachine
  $ nv net.nfsport=2049
  $ nv boot.default=/mnt/nfs

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 fs/nfs.c | 55 ++++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 36 insertions(+), 19 deletions(-)

diff --git a/fs/nfs.c b/fs/nfs.c
index 9785a313d831..fb76c205db26 100644
--- a/fs/nfs.c
+++ b/fs/nfs.c
@@ -34,6 +34,7 @@
 #include <byteorder.h>
 #include <globalvar.h>
 #include <parseopt.h>
+#include <magicvar.h>
 
 #define SUNRPC_PORT     111
 
@@ -1390,6 +1391,7 @@ static const struct super_operations nfs_ops = {
 };
 
 static char *rootnfsopts;
+static int nfsport_default;
 
 static void nfs_set_rootarg(struct nfs_priv *npriv, struct fs_device *fsdev)
 {
@@ -1467,30 +1469,41 @@ static int nfs_probe(struct device *dev)
 	/* Need a priviliged source port */
 	net_udp_bind(npriv->con, 1000);
 
-	parseopt_hu(fsdev->options, "mountport", &npriv->mount_port);
-	if (!npriv->mount_port) {
-		ret = rpc_lookup_req(npriv, PROG_MOUNT, 3);
-		if (ret < 0) {
-			printf("lookup mount port failed with %d\n", ret);
-			goto err2;
+	if (nfsport_default == 0) {
+		parseopt_hu(fsdev->options, "mountport", &npriv->mount_port);
+		if (!npriv->mount_port) {
+			ret = rpc_lookup_req(npriv, PROG_MOUNT, 3);
+			if (ret < 0) {
+				printf("lookup mount port failed with %d\n", ret);
+				goto err2;
+			}
+			npriv->mount_port = ret;
+		} else {
+			npriv->manual_mount_port = 1;
 		}
-		npriv->mount_port = ret;
-	} else {
-		npriv->manual_mount_port = 1;
-	}
-	debug("mount port: %hu\n", npriv->mount_port);
 
-	parseopt_hu(fsdev->options, "port", &npriv->nfs_port);
-	if (!npriv->nfs_port) {
-		ret = rpc_lookup_req(npriv, PROG_NFS, 3);
-		if (ret < 0) {
-			printf("lookup nfs port failed with %d\n", ret);
-			goto err2;
+		parseopt_hu(fsdev->options, "port", &npriv->nfs_port);
+		if (!npriv->nfs_port) {
+			ret = rpc_lookup_req(npriv, PROG_NFS, 3);
+			if (ret < 0) {
+				printf("lookup nfs port failed with %d\n", ret);
+				goto err2;
+			}
+			npriv->nfs_port = ret;
+		} else {
+			npriv->manual_nfs_port = 1;
 		}
-		npriv->nfs_port = ret;
 	} else {
-		npriv->manual_nfs_port = 1;
+		if (nfsport_default > U16_MAX) {
+			printf("invalid NFS port: %d\n", nfsport_default);
+			return -EINVAL;
+		}
+
+		npriv->mount_port = npriv->nfs_port = nfsport_default;
+		npriv->manual_nfs_port = npriv->manual_mount_port = 1;
 	}
+
+	debug("mount port: %hu\n", npriv->mount_port);
 	debug("nfs port: %d\n", npriv->nfs_port);
 
 	ret = nfs_mount_req(npriv);
@@ -1555,7 +1568,11 @@ static int nfs_init(void)
 	rootnfsopts = xstrdup("v3,tcp");
 
 	globalvar_add_simple_string("linux.rootnfsopts", &rootnfsopts);
+	globalvar_add_simple_int("net.nfsport", &nfsport_default, "%d");
 
 	return register_fs_driver(&nfs_driver);
 }
 coredevice_initcall(nfs_init);
+
+BAREBOX_MAGICVAR(global.net.nfsport,
+		 "Sets both NFS -o {port.mountport}= to the specified non-zero value");
-- 
2.39.5