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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 9EF52C7618B for ; Thu, 25 Jul 2019 15:29:57 +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 78A2421951 for ; Thu, 25 Jul 2019 15:29:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 78A2421951 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]:32908 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hqfgq-0005xX-No for qemu-devel@archiver.kernel.org; Thu, 25 Jul 2019 11:29:56 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48540) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hqfgg-0005V4-M0 for qemu-devel@nongnu.org; Thu, 25 Jul 2019 11:29:47 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hqfgf-00014d-L1 for qemu-devel@nongnu.org; Thu, 25 Jul 2019 11:29:46 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35060) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hqfgc-00013g-W2; Thu, 25 Jul 2019 11:29:43 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 3F6F1C085EE3; Thu, 25 Jul 2019 15:29:42 +0000 (UTC) Received: from maximlenovopc.usersys.redhat.com (unknown [10.35.206.87]) by smtp.corp.redhat.com (Postfix) with ESMTP id D18C11001B07; Thu, 25 Jul 2019 15:29:40 +0000 (UTC) Message-ID: <964c02ca6c18c2bd1f2e4885fbb7cbfbcd802f45.camel@redhat.com> From: Maxim Levitsky To: Max Reitz , qemu-block@nongnu.org Date: Thu, 25 Jul 2019 18:29:39 +0300 In-Reply-To: <20190724171239.8764-7-mreitz@redhat.com> References: <20190724171239.8764-1-mreitz@redhat.com> <20190724171239.8764-7-mreitz@redhat.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Thu, 25 Jul 2019 15:29:42 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH v2 06/11] qcow2: Fix .bdrv_has_zero_init() 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 , qemu-devel@nongnu.org, Stefano Garzarella Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, 2019-07-24 at 19:12 +0200, Max Reitz wrote: > If a qcow2 file is preallocated, it can no longer guarantee that it > initially appears as filled with zeroes. > > So implement .bdrv_has_zero_init() by checking whether the file is > preallocated; if so, forward the call to the underlying storage node, > except for when it is encrypted: Encrypted preallocated images always > return effectively random data, so .bdrv_has_zero_init() must always > return 0 for them. > > .bdrv_has_zero_init_truncate() can remain bdrv_has_zero_init_1(), > because it presupposes PREALLOC_MODE_OFF. > > Reported-by: Stefano Garzarella > Signed-off-by: Max Reitz > --- > block/qcow2.c | 29 ++++++++++++++++++++++++++++- > 1 file changed, 28 insertions(+), 1 deletion(-) > > diff --git a/block/qcow2.c b/block/qcow2.c > index 5c40f54d64..b4e73aa443 100644 > --- a/block/qcow2.c > +++ b/block/qcow2.c > @@ -4631,6 +4631,33 @@ static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs, > return spec_info; > } > > +static int qcow2_has_zero_init(BlockDriverState *bs) > +{ > + BDRVQcow2State *s = bs->opaque; > + bool preallocated; > + > + if (qemu_in_coroutine()) { > + qemu_co_mutex_lock(&s->lock); > + } > + /* > + * Check preallocation status: Preallocated images have all L2 > + * tables allocated, nonpreallocated images have none. It is > + * therefore enough to check the first one. > + */ > + preallocated = s->l1_size > 0 && s->l1_table[0] != 0; > + if (qemu_in_coroutine()) { > + qemu_co_mutex_unlock(&s->lock); > + } > + > + if (!preallocated) { > + return 1; > + } else if (bs->encrypted) { > + return 0; > + } else { > + return bdrv_has_zero_init(s->data_file->bs); > + } > +} > + > static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, > int64_t pos) > { > @@ -5186,7 +5213,7 @@ BlockDriver bdrv_qcow2 = { > .bdrv_child_perm = bdrv_format_default_perms, > .bdrv_co_create_opts = qcow2_co_create_opts, > .bdrv_co_create = qcow2_co_create, > - .bdrv_has_zero_init = bdrv_has_zero_init_1, > + .bdrv_has_zero_init = qcow2_has_zero_init, > .bdrv_has_zero_init_truncate = bdrv_has_zero_init_1, > .bdrv_co_block_status = qcow2_co_block_status, > Reviewed-by: Maxim Levitsky Best regards, Maxim Levitsky