Return-Path: Received: from fieldses.org ([174.143.236.118]:51919 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754661Ab0LOVs5 (ORCPT ); Wed, 15 Dec 2010 16:48:57 -0500 Date: Wed, 15 Dec 2010 16:48:55 -0500 From: "J. Bruce Fields" To: Trond Myklebust Cc: Simon Kirby , linux-nfs@vger.kernel.org Subject: Re: System CPU increasing on idle 2.6.36 Message-ID: <20101215214854.GC9646@fieldses.org> References: <20101215011021.GA24594@hostway.ca> <20101215015609.GB24594@hostway.ca> <20101215180813.GA7773@fieldses.org> <1292437333.3068.14.camel@heimdal.trondhjem.org> <20101215183816.GB7773@fieldses.org> <1292441630.3068.55.camel@heimdal.trondhjem.org> <20101215194956.GA9646@fieldses.org> <1292443028.3068.60.camel@heimdal.trondhjem.org> <20101215201908.GB9646@fieldses.org> <1292445128.3068.71.camel@heimdal.trondhjem.org> Content-Type: text/plain; charset=us-ascii In-Reply-To: <1292445128.3068.71.camel@heimdal.trondhjem.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 On Wed, Dec 15, 2010 at 03:32:08PM -0500, Trond Myklebust wrote: > On Wed, 2010-12-15 at 15:19 -0500, J. Bruce Fields wrote: > > > Could you give an example of a case in which all of the following are > > true?: > > - the administrator explicitly requests numeric id's (for > > example by setting nfs4_disable_idmapping). > > - numeric id's work as long as the client uses auth_sys. > > - they no longer work if that same client switches to krb5. > > Trivially: > > Server /etc/passwd maps trondmy to uid 1000 > Client /etc/passwd maps trondmy to uid 500 I understand that any problematic case would involve different name<->id mappings on the two sides. What I don't understand--and apologies if I'm being dense!--is what sequence of operations exactly would work in this situation if we automatically switch idmapping based on auth flavor, and would not work without it. Are you imagining a future client that is also able to switch auth flavors on the fly (say, based on whether a krb5 ticket exists or not), or just unmounting and remounting to change the security flavor? Are you thinking of creating a file under one flavor and accessing it under another? --b.