From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Walker Subject: Re: NFS mounts being mounted read-only depending upon mount order??? Date: Mon, 20 Nov 2006 12:57:48 -0800 Message-ID: <456216CC.40006@Cassatt.COM> References: <455DFE02.7050801@Cassatt.COM> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Cc: Michael Walker , nfs@lists.sourceforge.net Return-path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.91] helo=mail.sourceforge.net) by sc8-sf-list2-new.sourceforge.net with esmtp (Exim 4.43) id 1GmGDF-0002Sj-Vm for nfs@lists.sourceforge.net; Mon, 20 Nov 2006 12:57:58 -0800 Received: from 63-192-139-32.cassatt.com ([63.192.139.32] helo=GREYHOUND.cassatt.com) by mail.sourceforge.net with esmtp (Exim 4.44) id 1GmGDB-0001lG-3J for nfs@lists.sourceforge.net; Mon, 20 Nov 2006 12:57:56 -0800 To: Michael Walker In-Reply-To: <455DFE02.7050801@Cassatt.COM> List-Id: "Discussion of NFS under Linux development, interoperability, and testing." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: nfs-bounces@lists.sourceforge.net Errors-To: nfs-bounces@lists.sourceforge.net All, Any insights on this? I did find the following post from Trond which appears http://lkml.org/lkml/2006/10/18/264 Which seems to imply that this is a 'feature' and not a 'bug'? Is that true - or have I missed something? Thanx, _Mike_ Michael Walker wrote: > > All, > > I'm having problems with the latest version of FC5 which > contains kernel 2.6.18 - the problem is that NFS mounts > of read-write file-systems are being mounted read-only, sometimes. > > Whether a mount is mounted read-only or read-write seems > to very depending upon what other directories were > mounted from the same server and with what options. > > Take the following file-systems exported from my > Linux Server server: > > root@polyslo:/proc/fs/nfs# cat /etc/exports > /disk1/dir_ro *(ro,no_root_squash,sync,wdelay,no_subtree_check) > /disk1/dir_rw *(rw,no_root_squash,sync,wdelay,no_subtree_check) > root@polyslo:/proc/fs/nfs# showmount -e 10.20.20.48 > Export list for 10.20.20.48: > /disk1/dir_rw * > /disk1/dir_ro * > root@polyslo:/proc/fs/nfs# > > If I now do the following mounts (in this order): > > # Mount initial directory read-only - this is intentional > mount -t nfs -o ro 10.20.20.48:/disk1/dir_ro /tmp/dir_ro > > # Attempt to mount second directory read-write > mount -t nfs -o rw 10.20.20.48:/disk1/dir_rw /tmp/dir_rw > > # Now I attempt to touch a file in the rw directory: > [root@vt-1 tmp]# touch /tmp/dir_rw/hello > touch: cannot touch `/tmp/dir_rw/hello': Read-only file system > > # And if I take a look in the /proc/mounts directory - I see > # that the directory was truly mounted read-only > > [root@vt-1 tmp]# grep 10.20.20.48 /proc/mounts > 10.20.20.48:/disk1/dir_ro /tmp/dir_ro nfs > ro,vers=3,rsize=32768,wsize=32768,hard,proto=tcp,timeo=600,retrans=2,sec=sys,addr=10.20.20.48 > 0 0 > 10.20.20.48:/disk1/dir_rw /tmp/dir_rw nfs > ro,vers=3,rsize=32768,wsize=32768,hard,proto=tcp,timeo=600,retrans=2,sec=sys,addr=10.20.20.48 > 0 0 > [root@vt-1 tmp]# > > The above seems wrong to me - can someone clarify what's going on. > I know that this is new behavior that was not true in the past. My > RHEL_4U4 server running 2.6.9 kernel does not have this problem. > > Notice that if I change the order of the mounts I get different behavior: > > # Initially mount the read-write directory: > mount -t nfs -o rw 10.20.20.48:/disk1/dir_rw /tmp/dir_rw > > # Then mount the read-only directory: > mount -t nfs -o ro 10.20.20.48:/disk1/dir_ro /tmp/dir_ro > > # Now the directories are mounted as I wish, I can write to the > # read-write mount: > [root@vt-1 tmp]# touch /tmp/dir_rw/hello > [root@vt-1 tmp]# > > # And the read-only directory is read-only: > [root@vt-1 tmp]# touch /tmp/dir_ro/hello > touch: cannot touch `/tmp/dir_ro/hello': Read-only file system > [root@vt-1 tmp]# > > # And the /proc/mounts file reflects the states I expect > [root@vt-1 tmp]# grep 10.20.20.48 /proc/mounts > 10.20.20.48:/disk1/dir_rw /tmp/dir_rw nfs > rw,vers=3,rsize=32768,wsize=32768,hard,proto=tcp,timeo=600,retrans=2,sec=sys,addr=10.20.20.48 > 0 0 > 10.20.20.48:/disk1/dir_ro /tmp/dir_ro nfs > rw,vers=3,rsize=32768,wsize=32768,hard,proto=tcp,timeo=600,retrans=2,sec=sys,addr=10.20.20.48 > 0 0 > [root@vt-1 tmp]# > > > Note that previously the order did not matter and the permissions > always reflected the permissions of the individual mount requests. > > If someone could provide insights on what's going on above that > would be great. This is a artificial test case - but it's actually > hitting code we have in production and will be a significant > issue for us. > > Thanx much! > > _Mike_ ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ NFS maillist - NFS@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nfs