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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 03471C33CB1 for ; Thu, 16 Jan 2020 16:02:41 +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 C0A98207FF for ; Thu, 16 Jan 2020 16:02:40 +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="XDuWS5Sa" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C0A98207FF 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]:44302 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1is7bT-0004vU-Sq for qemu-devel@archiver.kernel.org; Thu, 16 Jan 2020 11:02:39 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:37664) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1is7Zq-0003jg-1U for qemu-devel@nongnu.org; Thu, 16 Jan 2020 11:00:59 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1is7Zm-0005aE-A2 for qemu-devel@nongnu.org; Thu, 16 Jan 2020 11:00:57 -0500 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:30264 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1is7Zm-0005a1-6H for qemu-devel@nongnu.org; Thu, 16 Jan 2020 11:00:54 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579190453; 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=QY3y3n8oMBLyjRhEFbm8Oi1kFEm7Eylb41TSMMKkUSM=; b=XDuWS5SatEO4rLMMqh64Gxh/0Ik1F7sUJOTGRFfgMswLhP1FW9dmqZC1J62ZUe2f1av90V 5v+KUJiwvdSGZlZPHHV3MFgwuD/qn7Yyf8HAk59Ddvdq/EluhoKeSW+aFkAVpMqG5RoGR9 Wm2JTVs8TdFpAj2HeC3yEAxYdrcgJtk= 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-96-sclrRCzgOM-GPeoXmMafpg-1; Thu, 16 Jan 2020 11:00:46 -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 D47F5107ACC7; Thu, 16 Jan 2020 16:00:45 +0000 (UTC) Received: from localhost (ovpn-117-237.ams2.redhat.com [10.36.117.237]) by smtp.corp.redhat.com (Postfix) with ESMTP id 69E0A60C84; Thu, 16 Jan 2020 16:00:45 +0000 (UTC) Date: Thu, 16 Jan 2020 16:00:44 +0000 From: "Richard W.M. Jones" To: Maxim Levitsky Subject: Re: Bug? qemu-img convert to preallocated image makes it sparse Message-ID: <20200116160044.GS3888@redhat.com> References: <20200116141352.GA32053@redhat.com> <7586b832-ecd2-e766-6781-3a25f382c9ed@redhat.com> <20200116145048.GG9470@linux.fritz.box> <5fcb531c-24ef-6e91-294d-517631c5a2cb@redhat.com> <03ebf1f7ad780fca65dfc7486e860beb33c71d20.camel@redhat.com> MIME-Version: 1.0 In-Reply-To: <03ebf1f7ad780fca65dfc7486e860beb33c71d20.camel@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: sclrRCzgOM-GPeoXmMafpg-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 205.139.110.61 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: Kevin Wolf , sgarzare@redhat.com, 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 Thu, Jan 16, 2020 at 05:38:03PM +0200, Maxim Levitsky wrote: > How about doing write zeros without discard only in this particular case = (convert to existing image) > Basically omitting the BDRV_REQ_MAY_UNMAP flag to blk_co_pwrite_zeroes. > It will be slow, but maybe for this particular case, it is acceptable? I should probably say that we don't want to break the other case (which is likely more important) where we write a sparse source to a sparse target and want the target to contain only the union of the two sparse maps, not fully allocated :-) It would be fine, I think, to have a new "make this disk fully allocated" operation. qemu-img resize could almost do it with a request to add 0 extra bytes, but the --preallocation flag only applies to the new space. Rich. --=20 Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjon= es Read my programming and virtualization blog: http://rwmj.wordpress.com virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://people.redhat.com/~rjones/virt-top