From: "david m. richter" Subject: Re: [PATCH 0/3] Intro: Better handling coarse-grained timestamps Date: Wed, 16 Jan 2008 15:09:45 -0500 (EST) Message-ID: References: <20080115162658.GA18911@newbie.thebellsplace.net> <20080116015526.GC26010@newbie.thebellsplace.net> <1200449912.28088.22.camel@heimdal.trondhjem.org> <1200512872.6932.8.camel@heimdal.trondhjem.org> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: Bob Bell , linux-nfs@vger.kernel.org To: Trond Myklebust Return-path: Received: from citi.umich.edu ([141.211.133.111]:21949 "EHLO citi.umich.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751248AbYAPUJq (ORCPT ); Wed, 16 Jan 2008 15:09:46 -0500 In-Reply-To: <1200512872.6932.8.camel-rJ7iovZKK19ZJLDQqaL3InhyD016LWXt@public.gmane.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Wed, 16 Jan 2008, Trond Myklebust wrote: > > On Wed, 2008-01-16 at 12:16 -0500, david m. richter wrote: > > so then, would it instead be correct to say that the negative > > dentry caching on the client afforded by the delegation is beneficial > > insofar as it obviates the client's need to revalidate the file/directory > > in question? if so, i understand the flawed CTO wording and will fix the > > wiki. > > Delegations give you a guarantee that the directory contents (i.e. the > readdir() information) have not changed, and so the client no longer > needs to poll the directory for change information. > > IOW: specifically they allow the client to optimise away the GETATTR > call in opendir(), and they allow it to optimise away most of > nfs_lookup_revalidate(). > > Cheers > Trond good, i'm on the same page as you here. thanks, trond, d .