Return-Path: linux-nfs-owner@vger.kernel.org Received: from mx11.netapp.com ([216.240.18.76]:23362 "EHLO mx11.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755553Ab3JXP1p convert rfc822-to-8bit (ORCPT ); Thu, 24 Oct 2013 11:27:45 -0400 From: "Myklebust, Trond" To: Simo Sorce CC: Christoph Anton Mitterer , Mailing List Linux NFS Subject: Re: XATTRs in NFS? Date: Thu, 24 Oct 2013 15:27:43 +0000 Message-ID: <48A37C8F-2E72-4865-A1EC-A430807F420A@netapp.com> References: <1382560643.6924.12.camel@heisenberg.scientia.net> <1382624000.6907.8.camel@heisenberg.scientia.net> <1382627225.899.76.camel@willson.li.ssimo.org> <1382627496.6430.2.camel@leira.trondhjem.org> <1382627770.899.79.camel@willson.li.ssimo.org> In-Reply-To: <1382627770.899.79.camel@willson.li.ssimo.org> Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org List-ID: On Oct 24, 2013, at 4:16 PM, Simo Sorce wrote: > On Thu, 2013-10-24 at 15:11 +0000, Myklebust, Trond wrote: >> On Thu, 2013-10-24 at 11:07 -0400, Simo Sorce wrote: >> >>> Because the filesystem can do that when multiple applications are >>> involved without having to change them all to talk to each other and >>> invent custom protocol all the time just to keep some additional >>> metadata associated to a file.. >>> >> It's still a custom protocol. The applications need to agree on a data >> format and store it somewhere. The portable way to do this is to write >> an application library that they can link to. > > Perhaps I was unclear, you are never going to see that custom library > linked into the 'mv' command. > Why should my mv need to link into such a library? > So your approach makes little sense if the object is to maintain data > coherent when people need to handle files from random applications and > scripts and general system maintenance. > See the earlier admonition: store data that needs to be kept together either in the same file, or in the same directory. Use a library when different applications need to access the same data. > The data may be relevant only to a specific application. > > I am not saying you *have* to implement xattrs support, just saying that > it is not a mere 'applications should synchronize data themselves' > problem. _portable_ applications do not use xattrs. They are a Linuxism that is not described by either POSIX or any other similar standard. Trond