Return-Path: linux-nfs-owner@vger.kernel.org Received: from fieldses.org ([174.143.236.118]:45970 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752480Ab3JYOIs (ORCPT ); Fri, 25 Oct 2013 10:08:48 -0400 Date: Fri, 25 Oct 2013 10:08:46 -0400 To: Christoph Anton Mitterer Cc: linux-nfs@vger.kernel.org Subject: Re: XATTRs in NFS? Message-ID: <20131025140846.GB20497@fieldses.org> References: <1382560643.6924.12.camel@heisenberg.scientia.net> <1382624000.6907.8.camel@heisenberg.scientia.net> <1382630468.6907.58.camel@heisenberg.scientia.net> <625CAA34-BD6C-4283-86D0-3F8B460D54D0@netapp.com> <1382635350.6907.83.camel@heisenberg.scientia.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1382635350.6907.83.camel@heisenberg.scientia.net> From: "J. Bruce Fields" Sender: linux-nfs-owner@vger.kernel.org List-ID: On Thu, Oct 24, 2013 at 07:22:30PM +0200, Christoph Anton Mitterer wrote: > On Thu, 2013-10-24 at 16:30 +0000, Myklebust, Trond wrote: > > Those programs need to recompute the checksum data anyway in order to > > verify and/or update it. Checksums that are computed by some third > > party application have exactly zero value for integrity checking. > No that's exactly the point,... the applications should _NOT_ set those > checksums, especially not automagically (since then you'd never notice > when just some application is buggy or writes/modifies when you don't > expect it to do so). > The idea is that there is on application (in my case it's just a > script), which sets the integrity data and verifies it. > > This works very well for e.g. large data archives, where you most of the > time (but not always) only read files, write new files or move around > existing ones - but only rarely modify existing file's contents. > > > I do this already like that on local filesystems, which works very > nicely with XATTRs... but now I want to move this on a central data > cluster (where clients connect to via NFS)... and here the problems > start... when I add new data to the archive (from the clients) I cannot > have XATTRs attached, nor can I verify them form the clients. Can you give any more details about your use case? (E.g. is there an article describing this system somewhere?) Just curious.--b.