From nobody Mon Feb 9 17:36:25 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1563988462; cv=none; d=zoho.com; s=zohoarc; b=OkqEdRmxZemuUGDwfF62ZZsUa1X0gREa51PXQnDbyw+nM6WsdySP6K4fCBISElvfsXNlxB7kRL48G2RLpF5fylsoVRpA7yQl1Wvci07VnOF81+dLCcdG0ytqZ5rQ7HoXgJvEvNzPq4n0Cz8mmErhxlBR2/oEgLoMe6ENvMgYQzA= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zoho.com; s=zohoarc; t=1563988462; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To:ARC-Authentication-Results; bh=k3ZYXRAMhxNhjbgYkua+5cghGLKEESVgQKsCwyVOFcA=; b=MwNaUFOXHDkwQRI2yXpV4x0750lw2czX7uesZqAUCGNSjta9ILdwZQl/xjHE11Uy+L1cySM9M2CrW4rbiV2WnujOMBwWk30OtgnE0w6+8DB8le2tRvrRhyNvbZ1UcLIykXW22xa0jLhcANroGlMEmyU+tBeIA92n3zSzDHEFUqY= ARC-Authentication-Results: i=1; mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1563988462274445.5290563608587; Wed, 24 Jul 2019 10:14:22 -0700 (PDT) Received: from localhost ([::1]:53634 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hqKqK-0000ah-Na for importer@patchew.org; Wed, 24 Jul 2019 13:14:20 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:49635) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hqKp7-0004Mr-Sh for qemu-devel@nongnu.org; Wed, 24 Jul 2019 13:13:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hqKp6-0005Up-N9 for qemu-devel@nongnu.org; Wed, 24 Jul 2019 13:13:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54318) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hqKp4-0005Hm-8i; Wed, 24 Jul 2019 13:13:02 -0400 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 mx1.redhat.com (Postfix) with ESMTPS id 994F9C03D478; Wed, 24 Jul 2019 17:13:01 +0000 (UTC) Received: from localhost (ovpn-204-115.brq.redhat.com [10.40.204.115]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 13AD919C70; Wed, 24 Jul 2019 17:13:00 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Wed, 24 Jul 2019 19:12:34 +0200 Message-Id: <20190724171239.8764-7-mreitz@redhat.com> In-Reply-To: <20190724171239.8764-1-mreitz@redhat.com> References: <20190724171239.8764-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Wed, 24 Jul 2019 17:13:01 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [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 , Stefano Garzarella , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="utf-8" 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 Reviewed-by: Maxim Levitsky --- 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(Bl= ockDriverState *bs, return spec_info; } =20 +static int qcow2_has_zero_init(BlockDriverState *bs) +{ + BDRVQcow2State *s =3D 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 =3D s->l1_size > 0 && s->l1_table[0] !=3D 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 =3D { .bdrv_child_perm =3D bdrv_format_default_perms, .bdrv_co_create_opts =3D qcow2_co_create_opts, .bdrv_co_create =3D qcow2_co_create, - .bdrv_has_zero_init =3D bdrv_has_zero_init_1, + .bdrv_has_zero_init =3D qcow2_has_zero_init, .bdrv_has_zero_init_truncate =3D bdrv_has_zero_init_1, .bdrv_co_block_status =3D qcow2_co_block_status, =20 --=20 2.21.0