From owner-freebsd-fs@FreeBSD.ORG Tue Sep 10 13:59:15 2013 Return-Path: Delivered-To: freebsd-fs@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id 34E413EF; Tue, 10 Sep 2013 13:59:15 +0000 (UTC) (envelope-from longwitz@incore.de) Received: from dss.incore.de (dss.incore.de [195.145.1.138]) by mx1.freebsd.org (Postfix) with ESMTP id DE66B2C6E; Tue, 10 Sep 2013 13:59:14 +0000 (UTC) Received: from inetmail.dmz (inetmail.dmz [10.3.0.3]) by dss.incore.de (Postfix) with ESMTP id 673BE5DD94; Tue, 10 Sep 2013 15:59:13 +0200 (CEST) X-Virus-Scanned: amavisd-new at incore.de Received: from dss.incore.de ([10.3.0.3]) by inetmail.dmz (inetmail.dmz [10.3.0.3]) (amavisd-new, port 10024) with LMTP id 08pB5SAMlQD2; Tue, 10 Sep 2013 15:59:12 +0200 (CEST) Received: from mail.incore (fwintern.dmz [10.0.0.253]) by dss.incore.de (Postfix) with ESMTP id B2F6A5DD8D; Tue, 10 Sep 2013 15:59:10 +0200 (CEST) Received: from bsdlo.incore (bsdlo.incore [192.168.0.84]) by mail.incore (Postfix) with ESMTP id A7EBE50BB0; Tue, 10 Sep 2013 15:59:10 +0200 (CEST) Message-ID: <522F25AE.1080309@incore.de> Date: Tue, 10 Sep 2013 15:59:10 +0200 From: Andreas Longwitz User-Agent: Thunderbird 2.0.0.19 (X11/20090113) MIME-Version: 1.0 To: Andriy Gapon Subject: Re: zfs panic during find(1) on zfs snapshot directory References: <522DF5A9.4070103@incore.de> <522E0118.5020106@FreeBSD.org> In-Reply-To: <522E0118.5020106@FreeBSD.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: freebsd-fs@FreeBSD.org X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 10 Sep 2013 13:59:15 -0000 Thanks for quick answer ! > My personal recommendation is to keep .zfs directory hidden and/or perform only > basic operations on entries under it while ensuring that there is only one > process at a time that peeks there. > > The gfs stuff that handles .zfs operations is really very broken on FreeBSD[*]. > If you are interested, I have a patch that should some of the mess, but not all. > > [*] To see what I mean run several of the following shell loops in parallel: > while true; do ls -l /pool/fs/.zfs/ >/dev/null; done Ok, I was not aware of the problematic caused by visible snapdir property. I think your recommendation to use the default snapdir property hidden is fine for me and the panic I have described will not happen again. On the other side a panic should not happen when a user configures something else than the default. Therefore I am interested in helping to test the broken gfs stuff on some of my test servers, so your offered patch is welcome. I run zfs on production for a half year now, and I like to note that this panic was the first problem on all of my (eight) production servers running zfs. The only open zfs problem I have is described in kern/180060. -- Andreas Longwitz