From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52396) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZpMxZ-0002QZ-Hs for qemu-devel@nongnu.org; Thu, 22 Oct 2015 16:59:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZpMxY-0002SR-Qv for qemu-devel@nongnu.org; Thu, 22 Oct 2015 16:59:41 -0400 Sender: Paolo Bonzini References: <1445495580-32129-1-git-send-email-famz@redhat.com> <1445495580-32129-12-git-send-email-famz@redhat.com> <20151022105345.GF3941@noname.redhat.com> From: Paolo Bonzini Message-ID: <56294E34.1080805@redhat.com> Date: Thu, 22 Oct 2015 22:59:32 +0200 MIME-Version: 1.0 In-Reply-To: <20151022105345.GF3941@noname.redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v6 11/12] qed: Implement .bdrv_drain List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf , Fam Zheng Cc: jcody@redhat.com, qemu-block@nongnu.org, qemu-devel@nongnu.org, stefanha@redhat.com On 22/10/2015 12:53, Kevin Wolf wrote: > Am 22.10.2015 um 08:32 hat Fam Zheng geschrieben: >> The "need_check_timer" is used to clear the "NEED_CHECK" flag in the >> image header after a grace period once metadata update has finished. In >> compliance to the bdrv_drain semantics we should make sure it remains >> deleted once .bdrv_drain is called. >> >> We cannot reuse qed_need_check_timer_cb because it calls bdrv_aio_flush >> with a completion callback that starts more I/O, bdrv_drain cannot cope >> with this. > > For the record: I discussed this with Fam on IRC and we came to the > conclusion that we should instead fix bdrv_drain() to correctly drain > in-flight flushes. > > In order to achieve this, Fam will send a series that adds a > BdrvTrackedRequest to all remaining asynchronous operations. So far we > have identified flush, discard and aio_ioctl. At the same time he will > send a rebased version of this series that goes back to asynchronous > flushing in bdrv_qed_drain(). This is a completely separate bug. Can you at least merge all patches except this, so that everything except QED can do snapshots with dataplane? Of course there will be a v7 at least for patch 9. Paolo