From owner-freebsd-net@FreeBSD.ORG Mon Apr 4 19:37:22 2011 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 8C0A41065672 for ; Mon, 4 Apr 2011 19:37:22 +0000 (UTC) (envelope-from scrappy@hub.org) Received: from hub.org (hub.org [200.46.204.220]) by mx1.freebsd.org (Postfix) with ESMTP id 580A38FC21 for ; Mon, 4 Apr 2011 19:37:22 +0000 (UTC) Received: from maia.hub.org (maia-5.hub.org [200.46.204.29]) by hub.org (Postfix) with ESMTP id E5B333250A96; Mon, 4 Apr 2011 16:37:20 -0300 (ADT) Received: from hub.org ([200.46.204.220]) by maia.hub.org (mx1.hub.org [200.46.204.29]) (amavisd-maia, port 10024) with ESMTP id 99126-06; Mon, 4 Apr 2011 19:37:21 +0000 (UTC) Received: by hub.org (Postfix, from userid 1002) id B2CEF3250A87; Mon, 4 Apr 2011 16:37:20 -0300 (ADT) Received: from localhost (localhost [127.0.0.1]) by hub.org (Postfix) with ESMTP id AA5963250A81; Mon, 4 Apr 2011 16:37:20 -0300 (ADT) Date: Mon, 4 Apr 2011 16:37:20 -0300 (ADT) From: "Marc G. Fournier" To: Chuck Swiger In-Reply-To: Message-ID: References: <0F56F33B-C492-4723-B7EC-713AD64E856C@mac.com> User-Agent: Alpine 2.00 (BSF 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: freebsd-net@freebsd.org Subject: Re: 7-STABLE NFS: fatal: "select lock: Permission denied" X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 04 Apr 2011 19:37:22 -0000 On Mon, 4 Apr 2011, Chuck Swiger wrote: > On Apr 4, 2011, at 12:14 PM, Marc G. Fournier wrote: >>> OK-- Cyrus IMAP uses a variant of maildir, so you're relatively safe even if locking is not available. >> >> So, just to get this clear ... >> >> If I were to boot a diskless station using an NFS backend, then that instance would be prone to corruption since lockd wouldn't work, even though the only processes handling the files on that mount? > > If you're running a diskless system using NFS filesystem for storage, > and you run stuff that wants to do fcntl/lockf/flock locking, and > rpc.lockd isn't available, then yes, there is risk of data corruption. > However, Postfix can use .dotfile locking, even if fcntl (etc) locking > is broken, and maildir is designed to avoid needing locking the way mbox > does: > > http://www.postfix.org/NFS_README.html > > rpc.lockd provides locking at the filesystem level. Locks are performed > against file descriptors either for entire files or record-level > locking; they are not specific to a single process (indeed, locking > would be mostly useless if it was only visible within a single process). Okay, next question ... if lockd is running, should fcntl locks work? My read of the NFS_README.html above indicates to me that they should ... but if that is the case, then it comes back to why doesn't it? ---- Marc G. Fournier Hub.Org Hosting Solutions S.A. scrappy@hub.org http://www.hub.org Yahoo:yscrappy Skype: hub.org ICQ:7615664 MSN:scrappy@hub.org