Received-SPF: pass (google.com: domain of linux-nfs-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Thu, 3 Feb 2022 18:47:28 +0530
From:   Rohan Sable <rsable@redhat.com>
To:     linux-nfs@vger.kernel.org
Cc:     rohanjsable@gmail.com
Subject: [PATCH] Fix error reporting for already mounted shares.
Message-ID: <YfvV6O+accmE0yVb@fedora.rsable.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Precedence: bulk

When mount is triggered for an already mounted
share (using auto negotiation), it displays
"mount.nfs: Protocol not supported" or
"mount.nfs: access denied by server while mounting"
instead of EBUSY. This easily causes confusion if
the mount was not tried verbose :

[root@rsable ~]# mount 127.0.0.1:/export /mnt
mount.nfs: Protocol not supported

[root@rsable ~]# mount -v 127.0.0.1:/export /mnt
mount.nfs: timeout set for Mon Apr  5 16:03:53 2021
mount.nfs: trying text-based options 'vers=4.2,addr=127.0.0.1,clientaddr=127.0.0.1'
mount.nfs: mount(2): Protocol not supported
mount.nfs: trying text-based options 'vers=4,minorversion=1,addr=127.0.0.1,clientaddr=127.0.0.1'
mount.nfs: mount(2): Protocol not supported
mount.nfs: trying text-based options 'vers=4,addr=127.0.0.1,clientaddr=127.0.0.1'
mount.nfs: mount(2): Protocol not supported
mount.nfs: trying text-based options 'addr=127.0.0.1'
mount.nfs: prog 100003, trying vers=3, prot=6
mount.nfs: trying 127.0.0.1 prog 100003 vers 3 prot TCP port 2049
mount.nfs: prog 100005, trying vers=3, prot=17
mount.nfs: trying 127.0.0.1 prog 100005 vers 3 prot UDP port 20048
mount.nfs: mount(2): Device or resource busy  << actual error
mount.nfs: Protocol not supported

[root@rsable ~]# mount rsable76server:/testshare /mnt
mount.nfs: access denied by server while mounting rsable76server:/testshare

[root@rsable ~]# mount rsable76server:/testshare /mnt -v
mount.nfs: timeout set for Mon Jan 17 13:36:16 2022
mount.nfs: trying text-based options 'vers=4.1,addr=192.168.122.58,clientaddr=192.168.122.82'
mount.nfs: mount(2): Permission denied
mount.nfs: trying text-based options 'vers=4.0,addr=192.168.122.58,clientaddr=192.168.122.82'
mount.nfs: mount(2): Permission denied
mount.nfs: trying text-based options 'addr=192.168.122.58'
mount.nfs: prog 100003, trying vers=3, prot=6
mount.nfs: trying 192.168.122.58 prog 100003 vers 3 prot TCP port 2049
mount.nfs: prog 100005, trying vers=3, prot=17
mount.nfs: trying 192.168.122.58 prog 100005 vers 3 prot UDP port 20048
mount.nfs: mount(2): Device or resource busy	<< actual error
mount.nfs: access denied by server while mounting rsable76server:/testshare

Signed-off-by: Rohan Sable <rsable@redhat.com>
Signed-off-by: Yongcheng Yang <yoyang@redhat.com>
---
 utils/mount/stropts.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/utils/mount/stropts.c b/utils/mount/stropts.c
index 3c4e218a..573df6ee 100644
--- a/utils/mount/stropts.c
+++ b/utils/mount/stropts.c
@@ -973,7 +973,9 @@ fall_back:
 	if ((result = nfs_try_mount_v3v2(mi, FALSE)))
 		return result;
 
-	errno = olderrno;
+	if (errno != EBUSY || errno != EACCES)
+		errno = olderrno;
+
 	return result;
 }
 
-- 
2.34.1