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 DBE6BC4CEC4 for ; Wed, 18 Sep 2019 10:03:38 +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 B1A12214AF for ; Wed, 18 Sep 2019 10:03:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B1A12214AF 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]:56840 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iAWoD-0002xQ-84 for qemu-devel@archiver.kernel.org; Wed, 18 Sep 2019 06:03:37 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59397) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iAWdM-0001PQ-KI for qemu-devel@nongnu.org; Wed, 18 Sep 2019 05:52:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iAWdL-0005tH-7m for qemu-devel@nongnu.org; Wed, 18 Sep 2019 05:52:24 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51496) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iAWdI-0005nU-El; Wed, 18 Sep 2019 05:52:20 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C4C82A3D394; Wed, 18 Sep 2019 09:52:19 +0000 (UTC) Received: from localhost (ovpn-116-168.ams2.redhat.com [10.36.116.168]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 430835C219; Wed, 18 Sep 2019 09:52:19 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Wed, 18 Sep 2019 11:51:43 +0200 Message-Id: <20190918095144.955-8-mreitz@redhat.com> In-Reply-To: <20190918095144.955-1-mreitz@redhat.com> References: <20190918095144.955-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.68]); Wed, 18 Sep 2019 09:52:19 +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 7/8] block: Pass truncate exact=true where reasonable 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 , Fam Zheng , qemu-devel@nongnu.org, Maxim Levitsky , Stefan Hajnoczi , Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" This is a change in behavior, so all instances need a good justification. The comments added here should explain my reasoning. qed already had a comment that suggests it always expected bdrv_truncate()/blk_truncate() to behave as if exact=3Dtrue were passed (c743849bee7 came eight months before 55b949c8476), so it was simply broken until now. Signed-off-by: Max Reitz --- block/parallels.c | 11 +++++++++-- block/qcow2.c | 6 +++++- block/qed.c | 2 +- qemu-img.c | 7 ++++++- qemu-io-cmds.c | 7 ++++++- 5 files changed, 27 insertions(+), 6 deletions(-) diff --git a/block/parallels.c b/block/parallels.c index a1a92c97a4..603211f83c 100644 --- a/block/parallels.c +++ b/block/parallels.c @@ -487,7 +487,12 @@ static int coroutine_fn parallels_co_check(BlockDriv= erState *bs, res->leaks +=3D count; if (fix & BDRV_FIX_LEAKS) { Error *local_err =3D NULL; - ret =3D bdrv_truncate(bs->file, res->image_end_offset, false= , + + /* + * In order to really repair the image, we must shrink it. + * That means we have to pass exact=3Dtrue. + */ + ret =3D bdrv_truncate(bs->file, res->image_end_offset, true, PREALLOC_MODE_OFF, &local_err); if (ret < 0) { error_report_err(local_err); @@ -880,7 +885,9 @@ static void parallels_close(BlockDriverState *bs) if ((bs->open_flags & BDRV_O_RDWR) && !(bs->open_flags & BDRV_O_INAC= TIVE)) { s->header->inuse =3D 0; parallels_update_header(bs); - bdrv_truncate(bs->file, s->data_end << BDRV_SECTOR_BITS, false, + + /* errors are ignored, so we might as well pass exact=3Dtrue */ + bdrv_truncate(bs->file, s->data_end << BDRV_SECTOR_BITS, true, PREALLOC_MODE_OFF, NULL); } =20 diff --git a/block/qcow2.c b/block/qcow2.c index 4ef19dd29a..eba165de7f 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -5057,7 +5057,11 @@ static int qcow2_amend_options(BlockDriverState *b= s, QemuOpts *opts, return ret; } =20 - ret =3D blk_truncate(blk, new_size, false, PREALLOC_MODE_OFF, er= rp); + /* + * Amending image options should ensure that the image has + * exactly the given new values, so pass exact=3Dtrue here. + */ + ret =3D blk_truncate(blk, new_size, true, PREALLOC_MODE_OFF, err= p); blk_unref(blk); if (ret < 0) { return ret; diff --git a/block/qed.c b/block/qed.c index 7c2a65af40..8005cfc305 100644 --- a/block/qed.c +++ b/block/qed.c @@ -674,7 +674,7 @@ static int coroutine_fn bdrv_qed_co_create(BlockdevCr= eateOptions *opts, l1_size =3D header.cluster_size * header.table_size; =20 /* File must start empty and grow, check truncate is supported */ - ret =3D blk_truncate(blk, 0, false, PREALLOC_MODE_OFF, errp); + ret =3D blk_truncate(blk, 0, true, PREALLOC_MODE_OFF, errp); if (ret < 0) { goto out; } diff --git a/qemu-img.c b/qemu-img.c index f8694f4f72..a3169b6113 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -3823,7 +3823,12 @@ static int img_resize(int argc, char **argv) } } =20 - ret =3D blk_truncate(blk, total_size, false, prealloc, &err); + /* + * The user expects the image to have the desired size after + * resizing, so pass @exact=3Dtrue. It is of no use to report + * success when the image has not actually been resized. + */ + ret =3D blk_truncate(blk, total_size, true, prealloc, &err); if (ret < 0) { error_report_err(err); goto out; diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c index 5e9017c979..1b7e700020 100644 --- a/qemu-io-cmds.c +++ b/qemu-io-cmds.c @@ -1710,7 +1710,12 @@ static int truncate_f(BlockBackend *blk, int argc,= char **argv) return offset; } =20 - ret =3D blk_truncate(blk, offset, false, PREALLOC_MODE_OFF, &local_e= rr); + /* + * qemu-io is a debugging tool, so let us be strict here and pass + * exact=3Dtrue. It is better to err on the "emit more errors" side + * than to be overly permissive. + */ + ret =3D blk_truncate(blk, offset, true, PREALLOC_MODE_OFF, &local_er= r); if (ret < 0) { error_report_err(local_err); return ret; --=20 2.21.0