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=-5.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 920D3C43603 for ; Fri, 13 Dec 2019 21:27:10 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1BA4D21655 for ; Fri, 13 Dec 2019 21:27:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Gtv7zyy1" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1BA4D21655 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 ([::1]:53384 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ifs3Y-0006Uo-Nm for qemu-devel@archiver.kernel.org; Fri, 13 Dec 2019 16:01:00 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:38001) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ifs2L-0005pg-70 for qemu-devel@nongnu.org; Fri, 13 Dec 2019 15:59:46 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ifs2H-0007O7-OE for qemu-devel@nongnu.org; Fri, 13 Dec 2019 15:59:43 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:40197 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ifs2H-0007KT-HS for qemu-devel@nongnu.org; Fri, 13 Dec 2019 15:59:41 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1576270780; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=t/gLqqtGE8AR2CYAo6pWp3+fioKxkjQmNsG9cuqgydI=; b=Gtv7zyy1Izvmb6xOf93/j6WCzjg6ip6uOnXlIzG+jx/Mp42nHHU+eBPkVD+wZs17Ia1Qf9 5oi9fueCBPy7cVsWdbU0hk57FXiwD6IvL43EjND/TnCs5erTfYY8dqpBFGqYfHZUH3PPzF QRRhEjlD9yE15scNYYhYGOFBjjILauY= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-148-WTZt4EzcMCC1juWTa7nAqw-1; Fri, 13 Dec 2019 15:59:38 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1FE898C4ECD; Fri, 13 Dec 2019 20:59:37 +0000 (UTC) Received: from [10.3.116.171] (ovpn-116-171.phx2.redhat.com [10.3.116.171]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 458B360BF3; Fri, 13 Dec 2019 20:59:34 +0000 (UTC) Subject: Re: [PATCH v5 4/4] blockdev: honor bdrv_try_set_aio_context() context requirements To: Kevin Wolf , Sergio Lopez References: <20191128104129.250206-1-slp@redhat.com> <20191128104129.250206-5-slp@redhat.com> <20191209160601.GB6715@linux.fritz.box> From: Eric Blake Organization: Red Hat, Inc. Message-ID: <7ea304ab-0a4b-8c0a-ae9f-2f6501198840@redhat.com> Date: Fri, 13 Dec 2019 14:59:33 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: <20191209160601.GB6715@linux.fritz.box> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: WTZt4EzcMCC1juWTa7nAqw-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 205.139.110.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Markus Armbruster , qemu-devel@nongnu.org, qemu-block@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 12/9/19 10:06 AM, Kevin Wolf wrote: > Am 28.11.2019 um 11:41 hat Sergio Lopez geschrieben: >> bdrv_try_set_aio_context() requires that the old context is held, and >> the new context is not held. Fix all the occurrences where it's not >> done this way. >> >> Suggested-by: Max Reitz >> Signed-off-by: Sergio Lopez >> --- > Or in fact, I think you need to hold the AioContext of a bs to > bdrv_unref() it, so maybe 'goto out' is right, but you need to unref > target_bs while you still hold old_context. I suspect https://bugzilla.redhat.com/show_bug.cgi?id=1779036 is also a symptom of this. The v5 patch did not fix this simple test case: $ qemu-img create -f qcow2 f1 100m $ qemu-img create -f qcow2 f2 100m $ ./qemu-kvm -nodefaults -nographic -qmp stdio -object iothread,id=io0 \ -drive driver=qcow2,id=drive1,file=f1,if=none -device virtio-scsi-pci,id=scsi0,iothread=io0 -device scsi-hd,id=image1,drive=drive1 \ -drive driver=qcow2,id=drive2,file=f2,if=none -device virtio-blk-pci,id=image2,drive=drive2,iothread=io0 {'execute':'qmp_capabilities'} {'execute':'transaction','arguments':{'actions':[ {'type':'blockdev-snapshot-sync','data':{'device':'drive1', 'snapshot-file':'sn1','mode':'absolute-paths','format':'qcow2'}}, {'type':'blockdev-snapshot-sync','data':{'device':'drive2', 'snapshot-file':'/aa/sn1','mode':'absolute-paths','format':'qcow2'}}]}} which is an aio context bug somewhere on the error path of blockdev-snapshot-sync (the first one has to be rolled back because the second part of the transaction fails early on a nonexistent directory) -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org