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 B6CB4C54FCB for ; Wed, 22 Apr 2020 15:35:16 +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 7BFBB2082E for ; Wed, 22 Apr 2020 15:35:16 +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="RrGze3Ny" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7BFBB2082E 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]:52910 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jRHP9-0003j8-2x for qemu-devel@archiver.kernel.org; Wed, 22 Apr 2020 11:35:15 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:39598) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jRHNX-0001wc-UA for qemu-devel@nongnu.org; Wed, 22 Apr 2020 11:33:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.90_1) (envelope-from ) id 1jRHNX-0006IJ-DX for qemu-devel@nongnu.org; Wed, 22 Apr 2020 11:33:35 -0400 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:20322 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 1jRHNW-0006Fm-WF for qemu-devel@nongnu.org; Wed, 22 Apr 2020 11:33:35 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1587569614; 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=MNTvpnxmpvg/ukbCJQ71DC8JDazmmNF4hvooQE2wAlk=; b=RrGze3NyDED6wyN2EFDUQ7PvAQY7i5mb/4ld7ibauy2SIpcpykBl+t12Th2OF2wfg7mkRb jGiqlomJtuikNA+fZWPms8e+DWNky3Ft64TK1AxWwgW6d/cScBmxVwMYvUQgfXAUVMR/Th kOKzUaFbUvnX+37HbOvLLGDy5d91ZzI= 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-117-K8UrEQyfMICSJmGLZgm4Pw-1; Wed, 22 Apr 2020 11:33:29 -0400 X-MC-Unique: K8UrEQyfMICSJmGLZgm4Pw-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id DC798107ACC7; Wed, 22 Apr 2020 15:33:27 +0000 (UTC) Received: from [10.10.116.80] (ovpn-116-80.rdu2.redhat.com [10.10.116.80]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 20FFD5DA66; Wed, 22 Apr 2020 15:33:26 +0000 (UTC) Subject: Re: [PATCH v5 4/9] qcow2: Support BDRV_REQ_ZERO_WRITE for truncate To: Kevin Wolf , qemu-block@nongnu.org References: <20200422152129.167074-1-kwolf@redhat.com> <20200422152129.167074-5-kwolf@redhat.com> From: Eric Blake Organization: Red Hat, Inc. Message-ID: <84c6ca49-aef3-adf4-2efe-68357dd20ce8@redhat.com> Date: Wed, 22 Apr 2020 10:33:25 -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: <20200422152129.167074-5-kwolf@redhat.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 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 = 2020/04/22 02:12:04 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 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: vsementsov@virtuozzo.com, berto@igalia.com, qemu-devel@nongnu.org, mreitz@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 4/22/20 10:21 AM, Kevin Wolf wrote: > If BDRV_REQ_ZERO_WRITE is set and we're extending the image, calling > qcow2_cluster_zeroize() with flags=0 does the right thing: It doesn't > undo any previous preallocation, but just adds the zero flag to all > relevant L2 entries. If an external data file is in use, a write_zeroes > request to the data file is made instead. > > Signed-off-by: Kevin Wolf > --- > block/qcow2.c | 30 ++++++++++++++++++++++++++++++ > 1 file changed, 30 insertions(+) > > @@ -4214,6 +4215,35 @@ static int coroutine_fn qcow2_co_truncate(BlockDriverState *bs, int64_t offset, > g_assert_not_reached(); > } > > + if ((flags & BDRV_REQ_ZERO_WRITE) && offset > old_length) { > + uint64_t zero_start = QEMU_ALIGN_UP(old_length, s->cluster_size); > + uint64_t zero_end = QEMU_ALIGN_UP(offset, s->cluster_size); This rounds up beyond the new size... > + > + /* Use zero clusters as much as we can */ > + ret = qcow2_cluster_zeroize(bs, zero_start, zero_end - zero_start, 0); and then requests that the extra be zeroed. Does that always work, even when it results in pdrv_co_pwrite_zeroes beyond the end of s->data_file? If so, Reviewed-by: Eric Blake otherwise, you may have to treat the tail specially, the same way you treated an unaligned head. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org