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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 09E08C433E0 for ; Tue, 19 May 2020 20:22:13 +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 B4EF4206C3 for ; Tue, 19 May 2020 20:22:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="HoeNEyd+" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B4EF4206C3 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]:50202 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jb8kd-0007qH-TR for qemu-devel@archiver.kernel.org; Tue, 19 May 2020 16:22:11 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58476) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jb8k5-0007Mi-9e for qemu-devel@nongnu.org; Tue, 19 May 2020 16:21:37 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:47584 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jb8k3-000185-SG for qemu-devel@nongnu.org; Tue, 19 May 2020 16:21:36 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1589919694; 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=tCStqeg/YykxJ8twekDulTTLNg5/SpTFMXo7X/mnHaM=; b=HoeNEyd+b/SfW6Imbd9tWQ5WUfof3FZ3JOHjB60434JePzLUR7A7JD9BSJB/CqHGLlEIG6 +N7kKcXkWQtvAm2gpc4lf8Y4YsPeaNMmH9JHfxK2u+dVfoeXNVCJZrEy3UJaLGWCIfr4c4 s5D6U8UjETJwQWSZLeIowIhF6qzveu0= 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-321-750LFhDXM_Kq44uxDY1KHA-1; Tue, 19 May 2020 16:21:32 -0400 X-MC-Unique: 750LFhDXM_Kq44uxDY1KHA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E39FF8018A7; Tue, 19 May 2020 20:21:30 +0000 (UTC) Received: from [10.3.112.88] (ovpn-112-88.phx2.redhat.com [10.3.112.88]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 34B824038; Tue, 19 May 2020 20:21:26 +0000 (UTC) Subject: Re: [PATCH v2 0/5] fix & merge block_status_above and is_allocated_above To: Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org References: <20200519195501.29071-1-vsementsov@virtuozzo.com> From: Eric Blake Organization: Red Hat, Inc. Message-ID: <1cfe5274-b3f7-e02f-8257-9858fdd4bb94@redhat.com> Date: Tue, 19 May 2020 15:21:26 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200519195501.29071-1-vsementsov@virtuozzo.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=207.211.31.81; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/19 00:34:39 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action 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: kwolf@redhat.com, fam@euphon.net, qemu-devel@nongnu.org, mreitz@redhat.com, stefanha@redhat.com, den@openvz.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 5/19/20 2:54 PM, Vladimir Sementsov-Ogievskiy wrote: > This leads to the following effect: > > ./qemu-img create -f qcow2 base.qcow2 2M > ./qemu-io -c "write -P 0x1 0 2M" base.qcow2 > > ./qemu-img create -f qcow2 -b base.qcow2 mid.qcow2 1M > ./qemu-img create -f qcow2 -b mid.qcow2 top.qcow2 2M > > Region 1M..2M is shadowed by short middle image, so guest sees zeroes: > ./qemu-io -c "read -P 0 1M 1M" top.qcow2 > read 1048576/1048576 bytes at offset 1048576 > 1 MiB, 1 ops; 00.00 sec (22.795 GiB/sec and 23341.5807 ops/sec) > > But after commit guest visible state is changed, which seems wrong for me: > ./qemu-img commit top.qcow2 -b mid.qcow2 > > ./qemu-io -c "read -P 0 1M 1M" mid.qcow2 > Pattern verification failed at offset 1048576, 1048576 bytes > read 1048576/1048576 bytes at offset 1048576 > 1 MiB, 1 ops; 00.00 sec (4.981 GiB/sec and 5100.4794 ops/sec) This no longer happens as of commit bf03dede47 and friends. As such, how much of this series is still needed for other reasons? -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org