From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:57674) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TP7ZJ-0002Ee-PX for qemu-devel@nongnu.org; Fri, 19 Oct 2012 04:04:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TP7ZA-0001XC-8H for qemu-devel@nongnu.org; Fri, 19 Oct 2012 04:04:33 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49323) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TP7Z9-0001X1-W3 for qemu-devel@nongnu.org; Fri, 19 Oct 2012 04:04:24 -0400 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q9J84NfV031441 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Fri, 19 Oct 2012 04:04:23 -0400 Message-ID: <50810982.1040102@redhat.com> Date: Fri, 19 Oct 2012 10:04:18 +0200 From: Kevin Wolf MIME-Version: 1.0 References: <1348675011-8794-1-git-send-email-pbonzini@redhat.com> <1348675011-8794-32-git-send-email-pbonzini@redhat.com> <507FFF21.2090007@redhat.com> <507FFFC7.2090800@redhat.com> <50800A92.4070005@redhat.com> <508017A3.4050600@redhat.com> In-Reply-To: <508017A3.4050600@redhat.com> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2 31/45] mirror: add support for on-source-error/on-target-error List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: jcody@redhat.com, qemu-devel@nongnu.org Am 18.10.2012 16:52, schrieb Paolo Bonzini: > Il 18/10/2012 15:56, Kevin Wolf ha scritto: >> Am 18.10.2012 15:10, schrieb Paolo Bonzini: >>> Il 18/10/2012 15:07, Kevin Wolf ha scritto: >>>>>> + s->synced = false; >>>>>> + if (read) { >>>>>> + return block_job_error_action(&s->common, s->common.bs, >>>>>> + s->on_source_error, true, error); >>>>>> + } else { >>>>>> + return block_job_error_action(&s->common, s->target, >>>>>> + s->on_target_error, false, error); >>>> Here we produce an event that reports an error on s->bs, i.e. on the >>>> source, even though the error was on the target. >>> >>> More precisely, this is an event that reports an error on s->bs's job. >>> In principle there is no reason why asynchronous long-running operations >>> are tied to a block device (in fact migration fits the definition quite >>> well, with the only twist that the VM is stopped at the end), but that's >>> the API we're stuck with. >> >> Yes, I think I mentioned already more than once that it shouldn't be >> block job, but background job without a reference to a (single) >> BlockDriverState. What we have just doesn't make any sense - even for >> block jobs, because block jobs working on a single BDS are the >> exception, not the rule. > > I'm quite at a loss with how to change this without breaking the API. :/ > > Unfortunately this came up after the first release with streaming. Then let's break the API. Not immediately, I think we can keep some useless compatibility fields in the implementation of background jobs that would only be needed to allow the block job commands to be a wrapper (mostly 'bool is_block_job' and 'BlockDriverState bs', I think; maybe even just char* bs_name would be enough). Then deprecate block jobs and at 1.6 or so remove them. Kevin