From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52500) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bDHTR-0006uC-LN for qemu-devel@nongnu.org; Wed, 15 Jun 2016 16:31:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bDHTN-0005SZ-G8 for qemu-devel@nongnu.org; Wed, 15 Jun 2016 16:31:40 -0400 Received: from mx1.parallels.com ([199.115.104.18]:59109) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bDHTN-0005SP-9x for qemu-devel@nongnu.org; Wed, 15 Jun 2016 16:31:37 -0400 References: <1465378757-15271-1-git-send-email-den@openvz.org> <20160608112357.GD5324@noname.str.redhat.com> <575FC184.4090903@openvz.org> <20160614084458.GD4916@noname.str.redhat.com> From: "Denis V. Lunev" Message-ID: <5761BB1F.6060702@virtuozzo.com> Date: Wed, 15 Jun 2016 23:31:27 +0300 MIME-Version: 1.0 In-Reply-To: <20160614084458.GD4916@noname.str.redhat.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 1/1] hmp: acquire aio_context in hmp_qemu_io List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf , "Denis V. Lunev" Cc: Paolo Bonzini , Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org On 06/14/2016 11:44 AM, Kevin Wolf wrote: > Am 14.06.2016 um 10:34 hat Denis V. Lunev geschrieben: >> On 06/08/2016 02:23 PM, Kevin Wolf wrote: >>> Am 08.06.2016 um 11:39 hat Denis V. Lunev geschrieben: >>>> From: Vladimir Sementsov-Ogievskiy >>>> >>>> Acquire aio context before run command, this is mandatory for unit tests. >>>> >>>> Signed-off-by: Vladimir Sementsov-Ogievskiy >>>> Signed-off-by: Denis V. Lunev >>>> CC: Kevin Wolf >>>> CC: Paolo Bonzini >>> Looks right to me, but why "mandatory for unit tests"? Does this fix an >>> observable bug in unit tests? If so, we should be more specific in the >>> commit message. >>> >>> But in fact, I would only expect it to make a difference for dataplane >>> and I don't think we have test cases that use both the 'qemu-io' HMP >>> command and dataplane. >>> >>> Kevin >> the problem is that it is usually difficult to understand that >> the problem is in locking and find where the locking is missed. >> Here we do have a place, which is used by unit testing, with >> a locking missed. >> >> May be now tests are not failing, but IMHO these tests MUST >> be fixed to accommodate future changes and thus this patch >> is mandatory for them. > I was never objecting to the patch, but just curious about the details > of a possible failure you were seeing because I didn't see how to hit > it in practice without dataplane. > > Sorry for forgetting about the patch, I've applied it now. > > Kevin > FYI: I have faced today the problematic case in current QEMU. Test number 132 could suffer from this issue. It performs 'discard' through qemu-io HMP command and have drive-mirror running, which uses dirty-bitmap. Den