From owner-freebsd-current@FreeBSD.ORG Sun Apr 5 11:34:29 2009 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 1D8C41065674 for ; Sun, 5 Apr 2009 11:34:29 +0000 (UTC) (envelope-from stb@lassitu.de) Received: from koef.zs64.net (koef.zs64.net [212.12.50.230]) by mx1.freebsd.org (Postfix) with ESMTP id A60DF8FC18 for ; Sun, 5 Apr 2009 11:34:27 +0000 (UTC) (envelope-from stb@lassitu.de) Received: from localhost by koef.zs64.net (8.14.3/8.14.3) with ESMTP id n35BYQu0057639 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NO); Sun, 5 Apr 2009 13:34:26 +0200 (CEST) (envelope-from stb@lassitu.de) (authenticated as stb) Message-Id: <98479514-21F9-4267-AD9F-DC697B7E0E0E@lassitu.de> From: Stefan Bethke To: Mark Powell In-Reply-To: <20090405120658.A24261@rust.salford.ac.uk> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (Apple Message framework v930.3) Date: Sun, 5 Apr 2009 13:34:25 +0200 References: <20090404124909.C24261@rust.salford.ac.uk> <190B8595-BAF8-41F5-B63F-64604672BFD3@lassitu.de> <20090405120658.A24261@rust.salford.ac.uk> X-Mailer: Apple Mail (2.930.3) Cc: freebsd-current@freebsd.org Subject: Re: panic: vput: negative ref cnt X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 05 Apr 2009 11:34:29 -0000 Am 05.04.2009 um 13:15 schrieb Mark Powell: > On Sun, 5 Apr 2009, Stefan Bethke wrote: > > Stefan, > Thanks for the input. > >> Am 04.04.2009 um 13:55 schrieb Mark Powell: >>> My script takes a zfs snapshot, mounts the snapshot, backs it up >>> using star, then umounts the snapshot. The panic seems to occur on >>> the umount. >> >> This is a different panic from the one I was getting, but appears >> to occur under the same circumstances. >> >> I managed to avoid the panic by keeping the snapshot until the next >> run of my backup script, and not unmounting anything. > > Yeah, I got around it by avoiding the unmount. > My script dates from 7-STABLE days, where a zfs bug caused the > automounted snapdir e.g. .zfs/snapshot/star_L0_2009-04-04-16:57, to > be missing a '..' entry. That prevented star from detecting that I > was performing a true full backup. Thus my script directly mounted > the snapshot to get a proper fs with a '..' entry and unmounted it > when finished. > Now the included version of zfs in 8-CURRENT doesn't have that bug > any longer. So I've reverted to backing up the automounted snapdir. > Consequently as I don't perform a mount I don't have to unmount > either, effectively working around the bug. > >> See > > > > Do you know if a PR has been submitted for this one? When I lasted searched for it about six weeks ago, I couldn't find any. I wanted to reproduce the panic in VMware first to gather more details, but I've been unsuccessful in triggering it there at all. Maybe I need to switch my production boxes over to VMware :-) Stefan -- Stefan Bethke Fon +49 151 14070811