From: Jamie Lokier Subject: Re: [PATCH 0/6][v4][RFC] NFSv3: implement extended attribute protocol (XATTR) Date: Mon, 15 Mar 2010 03:19:51 +0000 Message-ID: <20100315031951.GU6491@shareable.org> References: <20100309035932.GA14237@cynthia.pants.nu> <4B95E167.40306@schaufler-ca.com> <20100309070444.GA18216@cynthia.pants.nu> <20100309193545.GE11042@shareable.org> <4B971611.8030801@schaufler-ca.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Brad Boyer , James Morris , linux-nfs@vger.kernel.org, linux-security-module@vger.kernel.org, Trond Myklebust , "J. Bruce Fields" , Neil Brown , linux-fsdevel@vger.kernel.org To: Casey Schaufler Return-path: In-Reply-To: <4B971611.8030801@schaufler-ca.com> Sender: linux-security-module-owner@vger.kernel.org List-ID: Casey Schaufler wrote: > Jamie Lokier wrote: > > Brad Boyer wrote: > > > >> On Mon, Mar 08, 2010 at 09:49:27PM -0800, Casey Schaufler wrote: > >> > >>> Another is to NFS mount the filesystem back on to the server, > >>> in which case James' scheme works just dandy. It's a trick that > >>> I've used more than once in the Unix world for this exact purpose. > >>> Of course you have to arrange your mount points in advance with > >>> malice aforethought, but that's likely something you're used to > >>> by now. > >>> > >> That would definitely work, but it's not ideal. Obviously if it's > >> being accessed over NFS in one place it probably good enough > >> everywhere, but it's overhead that could be eliminated. > >> > > > > As a real example: > > > > Each user has a PC with their own home directory being local, fast > > storage, but /home is filled with NFS auto-mounts to everyone else's > > home directories, on their individual PCs. The auto-mount map has an > > exception, so the local user's home directory is a symlink to the > > local storage, instead of an NFS mount. > > > > A scheme like that works very well for occasional access to other > > peoples files, and for logging to each other's machines transparently, > > yet having fast performance for their own files when using their local > > machine. > > > > In an environment where I've used that, forcing local access to go > > over local NFS would have destroyed performance for things like big > > compiles, running find, git, grep etc. that people do on their own > > directories. > > > > > > Sure. The original objection can be readily addressed. There are > performance implications. Just like you'd have if the home directories > resided on a storage appliance. Some people pick security for the > masses over performance for the few. Some the other way round. > It's not an issue for people who want labeled NFS3 badly enough > to install it. It seems in this case, the performance implications are totally unnecassary. Why not a mount option for the xattr name translation? -- Jamie