Return-Path: linux-nfs-owner@vger.kernel.org Received: from mx1.redhat.com ([209.132.183.28]:44382 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751097AbaKKPUt (ORCPT ); Tue, 11 Nov 2014 10:20:49 -0500 Date: Tue, 11 Nov 2014 10:20:44 -0500 (EST) From: Benjamin Coddington To: Trond Myklebust cc: Linux NFS Mailing List Subject: Re: mount default minor version behavior In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-nfs-owner@vger.kernel.org List-ID: On Tue, 11 Nov 2014, Trond Myklebust wrote: > Hi Ben, > > On Tue, Nov 11, 2014 at 9:39 AM, Benjamin Coddington > wrote: > > I will update mount.nfs so the default version is 4.1. I have two quick > > questions on desired behavior: > > > > o Should mounts that do not specify a minor version be upgraded to the > > default minor version? > > > > For example, should 'mount -overs=4' turn into 'mount -overs4.1', if the > > current default is 4.1? > > > > > > o If 'yes' to the above, should mount auto-retry decrementing minor > > versions if EPROTONOSUPPORT? > > > > For example, 'mount -overs=4' with a default of 4.2 would attempt: 4.2, > > then 4.1, then 4.0. > > > > One thing you should note when doing this: the current parser for > /etc/nfsmount.conf does not support minor versions. I think it needs > to, so that we can continue to use it to set defaults. > > ...and to answer your questions above, I think that we should be able > to specify a 'default nfsv4 minor version' in /etc/nfsmount.conf, and > then negotiate down from there. > IOW: extend the 'Defaultvers' and 'Nfsvers' options to support 4.0, > 4.1, 4.2,.... Ah, good idea to make it configurable. > The result should be that If I do 'mount -t nfs' with no '-overs' > option, then we start at 4.1 (if that is the default in > /etc/nfsmount.conf) and then try 4.0, 3, 2 in that order. > If I do 'mount -t nfs -overs=4', then again consult /etc/nfsmount.conf; > - if there is a default matching a v4 minor version, then start at > that and negotiate down (but stop at 4.0). Yep, those closely match the current behavior and that's what my first pass looks like. > - if there is no default in /etc/nfsmount.conf, then perhaps assume a > default of 0(????) That's the question, and I think it will be a very common case. Do we want to have an idea of a "best" minor version, and use that if no minor version is specified? Ben > > Cheers > Trond > > > -- > Trond Myklebust > > Linux NFS client maintainer, PrimaryData > > trond.myklebust@primarydata.com >