From owner-freebsd-current@FreeBSD.ORG Wed Jan 11 17:42:47 2012 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 F00A8106564A for ; Wed, 11 Jan 2012 17:42:47 +0000 (UTC) (envelope-from gautam@execve.net) Received: from sng001.hawkhost.com (sng001.hawkhost.com [216.12.199.2]) by mx1.freebsd.org (Postfix) with ESMTP id 3ADC58FC0A for ; Wed, 11 Jan 2012 17:42:46 +0000 (UTC) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=default; d=execve.net; h=Date:From:To:Cc:Subject:Message-ID:References:Mime-Version:Content-Type:Content-Disposition:In-Reply-To:User-Agent:X-OS:X-Secure-Key; b=jad8oO3dSGu/a1YVchMkVMQUSqrRVh9mmBmRcSg5Cc+HCPvPBOWzajgvQ/fqPf6JpXFuvLaaXhnbIrWVki7zIzTobvIL8lXq42B5HIRESELXe3GkYLBc9wR6uXJ8Rtvo; Received: from [117.192.230.44] (port=53514 helo=linbox.localdomain) by sng001.hawkhost.com with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.69) (envelope-from ) id 1Rl2CB-001bDj-Bz; Thu, 12 Jan 2012 01:42:44 +0800 Received: by linbox.localdomain (Postfix, from userid 1001) id C81BA17052; Wed, 11 Jan 2012 23:12:35 +0530 (IST) Date: Wed, 11 Jan 2012 23:12:35 +0530 From: Gautam Mani To: Yamagi Burmeister , mckusick@mckusick.com Message-ID: <20120111225754.GAf9c67.linbox@execve.net> References: <20120109183051.1e4de3ca.lists@yamagi.org> <201201101830.q0AIUDP7062707@chez.mckusick.com> <20120111103039.d342aef4.lists@yamagi.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120111103039.d342aef4.lists@yamagi.org> User-Agent: Mutt/1.4.2.3i X-OS: FreeBSD 9.0-PRERELEASE X-Secure-Key: 0x7586EF34 [ A7E6 795F AF8D 91AF 1D5E 3CC5 7847 7DCC 7586 EF34 ] X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - sng001.hawkhost.com X-AntiAbuse: Original Domain - freebsd.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - execve.net Cc: freebsd-current@freebsd.org, bryce@bryce.net Subject: Re: FS hang when creating snapshots on a UFS SU+J setup 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: Wed, 11 Jan 2012 17:42:48 -0000 On Wed, Jan 11, 2012 at 10:30:39AM +0100, Yamagi Burmeister wrote: > Hello, > I've done some tests to verify that the problem only occures when SU+J > is used, but not SU without J. In fact, I did run the following two > loops on different TTYs in parallel: I also confirm this using a similar technique. The panic is only seen with SU+J and not with just SU. I did a similar cp -R /root /var/tmp ; rm -rf /var/tmp/root and the panic was trigger with dump -0L... I got the panic (again in less than a minute of issuing the dump command) -- I also got the "giving up on dirty" kind of message. I took a picture of the screen -- I am not sure if that helps! http://picpaste.com/11012012519-LF0sWlpw.jpg > Since it's much more likely that the problems described above arrise > when the the filesystem is loaded (for example by the first loop) while > taking the snapshot this looks like some kind of race condition or > something like that. > Earlier I have seen this happen with dump without any high load -- or atleast very minimum -- again with the /var because some logs were written or cronjob was running writing to it. That didnt panic as I indicated in my previous email -- hogged the CPU and forced a power-cycle. Do let me know if I can try something further. Thanks Gautam