Return-Path: Received: from mx2.netapp.com ([216.240.18.37]:58187 "EHLO mx2.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750884Ab1IZXJk convert rfc822-to-8bit (ORCPT ); Mon, 26 Sep 2011 19:09:40 -0400 Subject: Re: [PATCH] VFS: Suppress automount on [l]stat, [l]getxattr, etc. From: Trond Myklebust To: Linus Torvalds Cc: Ian Kent , Jeff Layton , Miklos Szeredi , David Howells , viro@zeniv.linux.org.uk, gregkh@suse.de, linux-nfs@vger.kernel.org, leonardo.lists@gmail.com Date: Mon, 26 Sep 2011 19:09:23 -0400 In-Reply-To: References: <1316747758.3346.89.camel@perseus.themaw.net> <20110922134510.24683.14576.stgit@warthog.procyon.org.uk> <1316707443.3346.44.camel@perseus.themaw.net> <1316709935.3346.48.camel@perseus.themaw.net> <20110922133529.6d3ea8de@barsoom.rdu.redhat.com> <20110922144453.6cf53a25@barsoom.rdu.redhat.com> <1316719228.3968.14.camel@lade.trondhjem.org> <2E1EB2CF9ED1CB4AA966F0EB76EAB4430B480BD4@SACMVEXC2-PRD.hq.netapp.com> <21772.1316774025@redhat.com> <1316788444.14812.10.camel@lade.trondhjem.org> <29743.1316791138@redhat.com> <87hb43tf2g.fsf@tucsk.pomaz.szeredi.hu> <1316827854.3346.154.camel@perseus.themaw.net> <20110924073610.4b045189@tlielax.poochiereds.net> <1317013864.3187.81.camel@perseus.themaw.net> <1317071626.19951.8.camel@lade.trondhjem.org> <1317072718.19951.13.camel@lade.trondhjem.org> <1317076424.19951.32.camel@lade.trondhjem.org> Content-Type: text/plain; charset="UTF-8" Message-ID: <1317078563.21770.8.camel@lade.trondhjem.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 On Mon, 2011-09-26 at 15:56 -0700, Linus Torvalds wrote: > On Mon, Sep 26, 2011 at 3:33 PM, Trond Myklebust > wrote: > > > > Lookup permission checks would be replaced with open permission checks > > on the server. > > > > IOW: the operation could potentially fail due to a completely unrelated > > issue. > > Quite frankly, that still sounds like a "I'm trying to make a problem > out of something that isn't actually a problem". And you still seem to > be unwilling to admit that LOOKUP_FOLLOW is a problem that has > actually been reported in real life, so you just cut out that part of > my question about how this would be a bigger issue. I never questioned your argument that we need to address the problem of regressions. That's why I cut out the LOOKUP_FOLLOW part. I just questioned your proposed solution because it seemed to introduce new problems. We're in the 3rd iteration of a bugfix (the first being the introduction of ->d_automount() and the second being Miklos's patch), and I'm assuming nobody is interested in seeing a 4th iteration. > But whatever. I can't really care, since it's a two-liner to add a new > flag, and then it falls down to "if you want to follow automounts, you > can set that flag instead". > > Almost nobody is ever going to bother setting the flag anyway, since > LOOKUP_OPEN and LOOKUP_DIRECTORY are going to take care of all the > common cases. > > So here. You can set LOOKUP_AUTOMOUNT to force an automount traversal. Ok? I assume that means that we can get rid of LOOKUP_NO_AUTOMOUNT, and just replace the convoluted logic in follow_automount() with a test for LOOKUP_AUTOMOUNT? If we have agreed on a default behaviour, then that would seem cleaner than enumerating all these exceptions. Cheers Trond -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@netapp.com www.netapp.com