Return-Path: linux-nfs-owner@vger.kernel.org Received: from fieldses.org ([174.143.236.118]:40195 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752127AbaFKOVE (ORCPT ); Wed, 11 Jun 2014 10:21:04 -0400 Date: Wed, 11 Jun 2014 10:21:02 -0400 From: "J. Bruce Fields" To: NeilBrown Cc: Trond Myklebust , NFS Subject: Re: Live lock in silly-rename. Message-ID: <20140611142102.GB19382@fieldses.org> References: <20140529164521.02324559@notabene.brown> <20140530075135.753fb7ed@notabene.brown> <20140530004423.GA13746@fieldses.org> <20140530134442.5a8e5983@notabene.brown> <20140530215522.GA27615@fieldses.org> <20140531081358.62ae69b3@notabene.brown> <20140604173926.53918af3@notabene.brown> <20140604220531.GA8362@fieldses.org> <20140605103423.43e21569@notabene.brown> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20140605103423.43e21569@notabene.brown> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Thu, Jun 05, 2014 at 10:34:23AM +1000, NeilBrown wrote: > On Wed, 4 Jun 2014 18:05:31 -0400 "J. Bruce Fields" > wrote: > > > On Wed, Jun 04, 2014 at 05:39:26PM +1000, NeilBrown wrote: > > > Below is my suggestion. It seems easy enough. It even works. > > > > Woah! > > > > Anyway, looks reasonable to me, and it fixes an immediate problem so I'm > > inclined to just apply. ... > And if you are going to apply it, you'll want: > > Signed-off-by: NeilBrown Oh, gah, then I forgot to actually apply. Anyway, it's a reasonably self-contained fix for an important bug so I'll send it as part of a later bugfix pull request. I thought it could also use a more explicit description of the resulting problem, so I added: ... so further delegations should not be handed out. The current code fails to do so, and the result is effectively a live-lock under some workloads: a client attempting a conflicting operation on a read-delegated file receives NFS4ERR_DELAY and retries the operation, but by the time it retries the server may already have given out another delegation. --b.