[PATCH] mount.nfs: Recognize v4.x mount options

[Weston Andros Adamson <dros@netapp.com>]

The kernel understands text options of the form "v4.x" (ie "v4.1"), but
mount.nfs does not and this leads to weird errors when the requested
mount fails: a line in dmesg about version 3 not supporting minorversions
and mount.nfs returning EINVAL no matter what the real error was.

This happens because mount.nfs thinks no version was specified so it starts
probing other versions which conflicts with the v4.X option once it gets
parsed by the kernel.

$ sudo mount -v -o v4.1 zero:/invalid_export /mnt
mount.nfs: timeout set for Wed Nov 13 10:09:48 2013
mount.nfs: trying text-based options 'v4.1,vers=4,addr=192.168.100.10,clientaddr=192.168.100.11'
mount.nfs: mount(2): No such file or directory
mount.nfs: trying text-based options 'v4.1,addr=192.168.100.10'
mount.nfs: prog 100003, trying vers=3, prot=6
mount.nfs: trying 192.168.100.10 prog 100003 vers 3 prot TCP port 2049
mount.nfs: prog 100005, trying vers=3, prot=17
mount.nfs: trying 192.168.100.10 prog 100005 vers 3 prot UDP port 20048
mount.nfs: mount(2): Invalid argument
mount.nfs: an incorrect mount option was specified

And you get this in dmesg:

NFS: mount option vers=3 does not support minorversion=1

but if you use another form of the same options, this doesn't happen:

$ sudo mount -v -o vers=4,minorversion=1 zero:/invalid_export /mnt
mount.nfs: timeout set for Wed Nov 13 10:10:28 2013
mount.nfs: trying text-based options 'vers=4,minorversion=1,addr=192.168.100.10,clientaddr=192.168.100.11'
mount.nfs: mount(2): No such file or directory
mount.nfs: mounting zero:/invalid_export failed, reason given by server: No such file or directory

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
---
 utils/mount/network.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/utils/mount/network.c b/utils/mount/network.c
index e8e55a5..2853d00 100644
--- a/utils/mount/network.c
+++ b/utils/mount/network.c
@@ -92,6 +92,9 @@ static const char *nfs_version_opttbl[] = {
 	"v4",
 	"vers",
 	"nfsvers",
+	"v4.0",
+	"v4.1",
+	"v4.2",
 	NULL,
 };
 
@@ -1269,6 +1272,11 @@ nfs_nfs_version(struct mount_options *options, unsigned long *version)
 					progname);
 			return 0;
 		}
+	case 5: /* v4.0 */
+	case 6: /* v4.1 */
+	case 7: /* v4.2 */
+		*version = 4;
+		return 1;
 	}
 
 	/*
-- 
1.8.3.1 (Apple Git-46)