From nobody Sun May 5 14:18:51 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; 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 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1510076139801278.852128157269; Tue, 7 Nov 2017 09:35:39 -0800 (PST) Received: from localhost ([::1]:54745 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eC7me-0001yd-S2 for importer@patchew.org; Tue, 07 Nov 2017 12:35:32 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54906) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eC7eN-0003lg-Ud for qemu-devel@nongnu.org; Tue, 07 Nov 2017 12:27:01 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eC7eM-0006Qh-OF for qemu-devel@nongnu.org; Tue, 07 Nov 2017 12:26:59 -0500 Received: from mx1.redhat.com ([209.132.183.28]:56982) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eC7eH-0006KV-F6; Tue, 07 Nov 2017 12:26:53 -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 mx1.redhat.com (Postfix) with ESMTPS id 54BFF806A4; Tue, 7 Nov 2017 17:26:52 +0000 (UTC) Received: from localhost.localdomain.com (ovpn-117-102.ams2.redhat.com [10.36.117.102]) by smtp.corp.redhat.com (Postfix) with ESMTP id EE57960C94; Tue, 7 Nov 2017 17:26:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 54BFF806A4 Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=kwolf@redhat.com From: Kevin Wolf To: qemu-block@nongnu.org Date: Tue, 7 Nov 2017 18:26:38 +0100 Message-Id: <20171107172638.29942-1-kwolf@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Tue, 07 Nov 2017 17:26:52 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH] block: Deprecate bdrv_set_read_only() and users X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, qemu-devel@nongnu.org, armbru@redhat.com, mreitz@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" bdrv_set_read_only() is used by some block drivers to override the read-only option given by the user. This is not how read-only images generally work in QEMU: Instead of second guessing what the user really meant (which currently includes making an image read-only even if the user didn't only use the default, but explicitly said read-only=3Doff), we should error out if we can't provide what the user requested. This adds deprecation warnings to all callers of bdrv_set_read_only() so that the behaviour can be corrected after the usual deprecation period. Signed-off-by: Kevin Wolf --- block.c | 5 +++++ block/bochs.c | 13 ++++++++++--- block/cloop.c | 13 ++++++++++--- block/dmg.c | 12 +++++++++--- block/rbd.c | 14 ++++++++++---- block/vvfat.c | 6 +++++- 6 files changed, 49 insertions(+), 14 deletions(-) diff --git a/block.c b/block.c index f6415547fe..0ed0c27140 100644 --- a/block.c +++ b/block.c @@ -261,6 +261,11 @@ int bdrv_can_set_read_only(BlockDriverState *bs, bool = read_only, return 0; } =20 +/* TODO Remove (deprecated since 2.11) + * Block drivers are not supposed to automatically change bs->read_only. + * Instead, they should just check whether they can provide what the user + * explicitly requested and error out if read-write is requested, but they= can + * only provide read-only access. */ int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp) { int ret =3D 0; diff --git a/block/bochs.c b/block/bochs.c index a759b6eff0..50c630047b 100644 --- a/block/bochs.c +++ b/block/bochs.c @@ -28,6 +28,7 @@ #include "block/block_int.h" #include "qemu/module.h" #include "qemu/bswap.h" +#include "qemu/error-report.h" =20 /**************************************************************/ =20 @@ -110,9 +111,15 @@ static int bochs_open(BlockDriverState *bs, QDict *opt= ions, int flags, return -EINVAL; } =20 - ret =3D bdrv_set_read_only(bs, true, errp); /* no write support yet */ - if (ret < 0) { - return ret; + if (!bdrv_is_read_only(bs)) { + error_report("Opening bochs images without an explicit read-only= =3Don " + "option is deprecated. Future versions will refuse to= " + "open the image instead of automatically marking the " + "image read-only."); + ret =3D bdrv_set_read_only(bs, true, errp); /* no write support ye= t */ + if (ret < 0) { + return ret; + } } =20 ret =3D bdrv_pread(bs->file, 0, &bochs, sizeof(bochs)); diff --git a/block/cloop.c b/block/cloop.c index d6597fcf78..2be68987bd 100644 --- a/block/cloop.c +++ b/block/cloop.c @@ -23,6 +23,7 @@ */ #include "qemu/osdep.h" #include "qapi/error.h" +#include "qemu/error-report.h" #include "qemu-common.h" #include "block/block_int.h" #include "qemu/module.h" @@ -72,9 +73,15 @@ static int cloop_open(BlockDriverState *bs, QDict *optio= ns, int flags, return -EINVAL; } =20 - ret =3D bdrv_set_read_only(bs, true, errp); - if (ret < 0) { - return ret; + if (!bdrv_is_read_only(bs)) { + error_report("Opening cloop images without an explicit read-only= =3Don " + "option is deprecated. Future versions will refuse to= " + "open the image instead of automatically marking the " + "image read-only."); + ret =3D bdrv_set_read_only(bs, true, errp); + if (ret < 0) { + return ret; + } } =20 /* read header */ diff --git a/block/dmg.c b/block/dmg.c index 6c0711f563..c9b3c519c4 100644 --- a/block/dmg.c +++ b/block/dmg.c @@ -419,9 +419,15 @@ static int dmg_open(BlockDriverState *bs, QDict *optio= ns, int flags, return -EINVAL; } =20 - ret =3D bdrv_set_read_only(bs, true, errp); - if (ret < 0) { - return ret; + if (!bdrv_is_read_only(bs)) { + error_report("Opening dmg images without an explicit read-only=3Do= n " + "option is deprecated. Future versions will refuse to= " + "open the image instead of automatically marking the " + "image read-only."); + ret =3D bdrv_set_read_only(bs, true, errp); + if (ret < 0) { + return ret; + } } =20 block_module_load_one("dmg-bz2"); diff --git a/block/rbd.c b/block/rbd.c index 144f350e1f..a76a5e8755 100644 --- a/block/rbd.c +++ b/block/rbd.c @@ -665,10 +665,16 @@ static int qemu_rbd_open(BlockDriverState *bs, QDict = *options, int flags, /* If we are using an rbd snapshot, we must be r/o, otherwise * leave as-is */ if (s->snap !=3D NULL) { - r =3D bdrv_set_read_only(bs, true, &local_err); - if (r < 0) { - error_propagate(errp, local_err); - goto failed_open; + if (!bdrv_is_read_only(bs)) { + error_report("Opening rbd snapshots without an explicit " + "read-only=3Don option is deprecated. Future vers= ions " + "will refuse to open the image instead of " + "automatically marking the image read-only."); + r =3D bdrv_set_read_only(bs, true, &local_err); + if (r < 0) { + error_propagate(errp, local_err); + goto failed_open; + } } } =20 diff --git a/block/vvfat.c b/block/vvfat.c index a0f2335894..0841cc42fc 100644 --- a/block/vvfat.c +++ b/block/vvfat.c @@ -1259,7 +1259,11 @@ static int vvfat_open(BlockDriverState *bs, QDict *o= ptions, int flags, "Unable to set VVFAT to 'rw' when drive is read-onl= y"); goto fail; } - } else { + } else if (!bdrv_is_read_only(bs)) { + error_report("Opening non-rw vvfat images without an explicit " + "read-only=3Don option is deprecated. Future versions= " + "will refuse to open the image instead of " + "automatically marking the image read-only."); /* read only is the default for safety */ ret =3D bdrv_set_read_only(bs, true, &local_err); if (ret < 0) { --=20 2.13.6