From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Tokarev Subject: Re: the >1Tb block issue Date: Tue, 18 May 2010 22:03:18 +0400 Message-ID: <4BF2D666.1080108@msgid.tls.msk.ru> References: <4BF2B7CD.7090204@msgid.tls.msk.ru> <4BF2CE70.1060402@redhat.com> <4BF2CFAB.1010505@msgid.tls.msk.ru> <4BF2D08E.7000505@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: KVM list , Christoph Hellwig To: Avi Kivity Return-path: Received: from isrv.corpit.ru ([81.13.33.159]:57375 "EHLO isrv.corpit.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756761Ab0ERSDV (ORCPT ); Tue, 18 May 2010 14:03:21 -0400 In-Reply-To: <4BF2D08E.7000505@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: 18.05.2010 21:38, Avi Kivity wrote: >> [Qemu-devel] [PATCH +stable] block: don't attempt to merge overlapping >> requests >> >> quick tests shows it works correctly so far. >> At least it went further than before, not >> stopping at the "usual" sector 3145727872. >> >> Hmm. Ide has no queue, hence no mergeing, >> that's why it does not occur with ide, >> right? :) > > Yes. I tried multiple times to reproduce it with if=scsi (queue_depth=16 for the sym53c8xx driver). I can't. JFYI.. ;) (And this kinda explains why the bug does not occur when run under strace; which also indicates that it isn't necessary easy to trigger it, too). >> Interesting... > > Yes. Why would Linux post overlapping requests? makes 0xffffffff00000000 > sense. It's mkfs. Not sure why, but yes, maybe it's a guest bug after all. Note that I'm running 64bit kernel on the guest (2.6.32.9-amd64). Note also that it's not as on the original bugreport - there, the sector# is apparently different: http://sourceforge.net/tracker/?func=detail&aid=2933400&group_id=180599&atid=893831 > There may be a guest bug in here too. Christoph? /mjt