From: "Paul Krizak" <paul.krizak@amd.com>
Subject: Re: inconsistent mount attributes (ro/rw), RHEL5 / Netapp
Date: Mon, 14 May 2007 10:56:06 -0500
Message-ID: <46488696.9080009@amd.com>
References: <4627B3DD.5050409@amd.com>
	<1177007479.6623.14.camel@heimdal.trondhjem.org>
	<4627D303.8060009@amd.com>
	<1177020662.6628.30.camel@heimdal.trondhjem.org>
	<4627EBFC.2090704@amd.com> <462CFC92.2080201@amd.com>
	<463B97E6.4030009@amd.com>
	<1178314889.6533.19.camel@heimdal.trondhjem.org>
	<1178379473.4559.24.camel@raven.themaw.net>
	<1178385472.6561.43.camel@heimdal.trondhjem.org>
	<20070514131743.GG31764@petra.dvoda.cz>
	<1179149048.6858.5.camel@heimdal.trondhjem.org>
	<1179153555.3811.57.camel@raven.themaw.net>
	<1179157631.6474.8.camel@heimdal.trondhjem.org>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Cc: nfs@lists.sourceforge.net, Ian Kent <raven@themaw.net>
To: "Trond Myklebust" <Trond.Myklebust@netapp.com>
In-Reply-To: <1179157631.6474.8.camel@heimdal.trondhjem.org>
Sender: nfs-bounces@lists.sourceforge.net
Errors-To: nfs-bounces@lists.sourceforge.net


 > We might then be able to add an '--unshared-cache' option (any
 > suggestions for a better name?) to mount in order to allow those people
 > who fully understand the consequences to override, and hence to mount
 > the same filesystem with different mount options, but no sharing of the
 > page cache with the original filesystem.

I can assure you that AMD systems engineering would *much* prefer having 
the VFS stack fixed such that we don't need to do something like this.

It would be much better to make the kernel understand that it *can* 
mount the same NFS filesystem twice, once read-only and again 
read-write, with the appropriate cache coherency, rather than force us 
to run in a potentially dangerous configuration that might lead to data 
corruption.

I agree with Ian that the VFS changes need to take priority.  The only 
change I see that needs to be made to mount is that it needs to spit out 
a warning (or fail completely) if the requested options cannot be satisfied.

Paul Krizak                         5900 E. Ben White Blvd. MS 625
Advanced Micro Devices              Austin, TX  78741
Linux/Unix Systems Engineering      Phone: (512) 602-8775
Silicon Design Division             Cell:  (512) 791-0686


-------------------------------------------------------------------------
This SF.net email is sponsored by DB2 Express
Download DB2 Express C - the FREE version of DB2 express and take
control of your XML. No limits. Just data. Click to get it now.
http://sourceforge.net/powerbar/db2/
_______________________________________________
NFS maillist  -  NFS@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/nfs