From 78bb645a42c216b37b8d930c7c849a3fa89babf8 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.com>
Date: Sat, 16 Jan 2016 12:02:30 -0500
Subject: [PATCH] Fix protocol minor version fall-back

mount.nfs currently expects mount(2) to fail with EPROTONOSUPPORT if
the kernel doesn't understand the requested NFS version.

Unfortunately if the requested minor is not known to the kernel
it returns -EINVAL.
In kernels since 3.11 this can happen in nfs4_alloc_client(), if
compiled without NFS_V4_2.

More generally it can happen in in nfs_validate_text_mount_data()
when nfs_parse_mount_options() returns 0 because
nfs_parse_version_string()
didn't recognise the version.

EPROTONOSUPPORT is only returned if NFSv4 support is completely compiled
out.

So nfs_autonegotiate needs to check for EINVAL as well as
EPROTONOSUPPORT.

URL: https://bugzilla.opensuse.org/show_bug.cgi?id=959211
Reported-by: Takashi Iwai <tiwai@suse.com>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Steve Dickson <steved@redhat.com>


Upstream-Status: Backport
http://git.linux-nfs.org/?p=steved/nfs-utils.git;a=patch;h=78bb645a42c216b37b8d930c7c849a3fa89babf8

Signed-off-by: Yi Zhao <yi.zhao@windriver.com>
---
 utils/mount/stropts.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/utils/mount/stropts.c b/utils/mount/stropts.c
index c8f5a6d..86829a9 100644
--- a/utils/mount/stropts.c
+++ b/utils/mount/stropts.c
@@ -841,6 +841,9 @@ check_result:
 	case EPROTONOSUPPORT:
 		/* A clear indication that the server or our
 		 * client does not support NFS version 4 and minor */
+	case EINVAL:
+		/* A less clear indication that our client
+		 * does not support NFSv4 minor version. */
 		if (mi->version.v_mode == V_GENERAL &&
 			mi->version.minor == 0)
 				return result;
-- 
2.7.4