From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A94E2C28CC5 for ; Wed, 5 Jun 2019 16:13:11 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 835FD2075C for ; Wed, 5 Jun 2019 16:13:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 835FD2075C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([127.0.0.1]:45708 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hYYXG-0008Lu-Ix for qemu-devel@archiver.kernel.org; Wed, 05 Jun 2019 12:13:10 -0400 Received: from eggs.gnu.org ([209.51.188.92]:59881) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hYYVh-0007PF-Nv for qemu-devel@nongnu.org; Wed, 05 Jun 2019 12:11:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hYYVf-0002Tv-0n for qemu-devel@nongnu.org; Wed, 05 Jun 2019 12:11:33 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39396) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hYYVc-0002MC-Mh; Wed, 05 Jun 2019 12:11:28 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 98852308338F; Wed, 5 Jun 2019 16:11:22 +0000 (UTC) Received: from localhost (unknown [10.40.205.15]) by smtp.corp.redhat.com (Postfix) with ESMTPS id EFFB25F7C0; Wed, 5 Jun 2019 16:11:19 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Wed, 5 Jun 2019 18:11:14 +0200 Message-Id: <20190605161118.14544-1-mreitz@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.44]); Wed, 05 Jun 2019 16:11:22 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH 0/4] block: Keep track of parent quiescing X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , qemu-devel@nongnu.org, Stefan Hajnoczi , Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" We currently do not keep track of how many times a child has quiesced its parent. We just guess based on the child=E2=80=99s quiesce_counter. = That keeps biting us when we try to leave drained sections or detach children (see e.g. commit 5cb2737e925042e). I think we need an explicit counter to keep track of how many times a parent has been quiesced (patch 1). That just makes the code more resilient. Actually, no, we don=E2=80=99t need a counter, we need a boolean. See pa= tch 2 for the explanation. Yes, it is a bit weird to introduce a counter first (patch 1) and then immediately make it a boolean (patch 2). But I believe this to be the most logical change set. (=E2=80=9COur current model relies on counting, so adding an explicit cou= nter makes sense. It then turns out that counting is probably not the best idea, so why not make it a boolean?=E2=80=9D) Max Reitz (4): block: Introduce BdrvChild.parent_quiesce_counter block: Make @parent_quiesced a bool iotests: Add @has_quit to vm.shutdown() iotests: Test commit with a filter on the chain include/block/block.h | 9 +++--- include/block/block_int.h | 6 ++++ block.c | 18 ++++------- block/io.c | 61 +++++++++++++++++++++++++++++--------- tests/test-bdrv-drain.c | 31 +++++++++++-------- python/qemu/__init__.py | 5 ++-- tests/qemu-iotests/040 | 40 ++++++++++++++++++++++++- tests/qemu-iotests/040.out | 4 +-- tests/qemu-iotests/255 | 2 +- 9 files changed, 126 insertions(+), 50 deletions(-) --=20 2.21.0