Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932196AbWHJVAX (ORCPT ); Thu, 10 Aug 2006 17:00:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932261AbWHJVAW (ORCPT ); Thu, 10 Aug 2006 17:00:22 -0400 Received: from mx1.redhat.com ([66.187.233.31]:50889 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S932254AbWHJVAT (ORCPT ); Thu, 10 Aug 2006 17:00:19 -0400 Message-ID: <44DB9E5E.3000207@redhat.com> Date: Thu, 10 Aug 2006 17:00:14 -0400 From: Peter Staubach User-Agent: Thunderbird 1.5.0.5 (X11/20060726) MIME-Version: 1.0 To: Xin Zhao CC: Matthew Wilcox , Neil Brown , linux-kernel , linux-fsdevel@vger.kernel.org Subject: Re: Urgent help needed on an NFS question, please help!!! References: <4ae3c140608092204n1c07152k52010a10e209bb77@mail.gmail.com> <17626.49136.384370.284757@cse.unsw.edu.au> <4ae3c140608092254k62dce9at2e8cdcc9ae7a6d9f@mail.gmail.com> <17626.52269.828274.831029@cse.unsw.edu.au> <4ae3c140608100815p57c0378kfd316a482738ee83@mail.gmail.com> <20060810161107.GC4379@parisc-linux.org> <4ae3c140608100923j1ffb5bb5qa776bff79365874c@mail.gmail.com> In-Reply-To: <4ae3c140608100923j1ffb5bb5qa776bff79365874c@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1354 Lines: 41 Xin Zhao wrote: > That makes sense. > > Can we make the following two conclusions? > 1. In a single machine, inode+dev ID+i_generation can uniquely > identify a file > 2. Given a stored file handle and an inode object received from the > server, an NFS client can safely determine whether this inode > corresponds to the file handle by checking the inode+dev+i_generation. > #1 seems to safe enough to assume. #2 either doesn't make sense to me or is assuming things about the file handle that the client is not allowed to assume. A file handle is an opaque string of bytes to the client. The only entity allowed to interpret the contents is the entity which generated the file handle. --- Is this situation any different than an application opens file, "A". Another process then renames "A" to "B". Now, the original application is reading and writing from and to a file called "B" and has no knowledge of this. --- The bottom line is that the file handle uniquely identifies a particular entity on a file system on the server. The name of the entity does not matter. Thanx... ps - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/