Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-vc0-f182.google.com ([209.85.220.182]:62134 "EHLO mail-vc0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757412AbbBEOt6 (ORCPT ); Thu, 5 Feb 2015 09:49:58 -0500 Received: by mail-vc0-f182.google.com with SMTP id kv19so2792139vcb.13 for ; Thu, 05 Feb 2015 06:49:57 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <20150205140701.GA3941@infradead.org> References: <1423000784-93180-1-git-send-email-trond.myklebust@primarydata.com> <1423000784-93180-2-git-send-email-trond.myklebust@primarydata.com> <20150205140701.GA3941@infradead.org> Date: Thu, 5 Feb 2015 09:49:57 -0500 Message-ID: Subject: Re: [PATCH 2/2] NFSv4.1: Ask for no delegation on OPEN if already holding one From: Trond Myklebust To: Christoph Hellwig Cc: Linux NFS Mailing List , "Kornievskaia, Olga" Content-Type: text/plain; charset=UTF-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: On Thu, Feb 5, 2015 at 9:07 AM, Christoph Hellwig wrote: > On Tue, Feb 03, 2015 at 04:59:44PM -0500, Trond Myklebust wrote: >> If we already hold a delegation, there should be no reason for the >> server to issue it to us again. Unfortunately, there appear to be >> servers out there that engage in this practice. While it is often >> harmless to do so, there is one case where this creates a problem >> and that is when the client is in the process of returning that >> delegation. >> This patch uses the NFSv4.1 NFS4_SHARE_WANT_NO_DELEG flag to inform >> the server not to return a delegation in these cases. > > Shouldn't this be patch 1 as it's the actual bug fix that might need > backporting? I'm dropping it instead. It doesn't completely close the race left open by the lack of clarity in the protocol, and so it is counterproductive; it will leave sloppy server vendors thinking the problem is solved when it isn't. -- Trond Myklebust Linux NFS client maintainer, PrimaryData trond.myklebust@primarydata.com