From nobody Wed Apr 16 03:52:00 2025 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.zoho.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 1493061889945351.6418484585947; Mon, 24 Apr 2017 12:24:49 -0700 (PDT) Received: from localhost ([::1]:45601 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d2jbM-00055x-Aj for importer@patchew.org; Mon, 24 Apr 2017 15:24:48 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46565) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d2jWz-0001ZK-50 for qemu-devel@nongnu.org; Mon, 24 Apr 2017 15:20:18 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1d2jWx-0002hE-LL for qemu-devel@nongnu.org; Mon, 24 Apr 2017 15:20:17 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36568) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1d2jWt-0002dQ-Q3; Mon, 24 Apr 2017 15:20:12 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C0BAFC04B95B; Mon, 24 Apr 2017 19:20:10 +0000 (UTC) Received: from localhost (ovpn-120-118.rdu2.redhat.com [10.10.120.118]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7522953CF1; Mon, 24 Apr 2017 19:20:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com C0BAFC04B95B Authentication-Results: ext-mx07.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx07.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=jcody@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com C0BAFC04B95B From: Jeff Cody To: qemu-block@nongnu.org Date: Mon, 24 Apr 2017 15:19:55 -0400 Message-Id: <20170424192002.18622-6-jcody@redhat.com> In-Reply-To: <20170424192002.18622-1-jcody@redhat.com> References: <20170424192002.18622-1-jcody@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Mon, 24 Apr 2017 19:20:10 +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] [PULL v2 05/12] block: do not set BDS read_only if copy_on_read enabled 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: peter.maydell@linaro.org, jcody@redhat.com, qemu-devel@nongnu.org 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" A few block drivers will set the BDS read_only flag from their .bdrv_open() function. This means the bs->read_only flag could be set after we enable copy_on_read, as the BDRV_O_COPY_ON_READ flag check occurs prior to the call to bdrv->bdrv_open(). This adds an error return to bdrv_set_read_only(), and an error will be return if we try to set the BDS to read_only while copy_on_read is enabled. This patch also changes the behavior of vvfat. Before, vvfat could override the drive 'readonly' flag with its own, internal 'rw' flag. For instance, this -drive parameter would result in a writable image: "-drive format=3Dvvfat,dir=3D/tmp/vvfat,rw,if=3Dvirtio,readonly=3Don" This is not correct. Now, attempting to use the above -drive parameter will result in an error (i.e., 'rw' is incompatible with 'readonly=3Don'). Signed-off-by: Jeff Cody Reviewed-by: Stefan Hajnoczi Reviewed-by: John Snow Message-id: 0c5b4c1cc2c651471b131f21376dfd5ea24d2196.1491597120.git.jcody@r= edhat.com --- block.c | 10 +++++++++- block/bochs.c | 5 ++++- block/cloop.c | 5 ++++- block/dmg.c | 6 +++++- block/rbd.c | 11 ++++++++++- block/vvfat.c | 19 +++++++++++++++---- include/block/block.h | 2 +- 7 files changed, 48 insertions(+), 10 deletions(-) diff --git a/block.c b/block.c index 6f21145..67ae35a 100644 --- a/block.c +++ b/block.c @@ -192,9 +192,17 @@ void path_combine(char *dest, int dest_size, } } =20 -void bdrv_set_read_only(BlockDriverState *bs, bool read_only) +int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp) { + /* Do not set read_only if copy_on_read is enabled */ + if (bs->copy_on_read && read_only) { + error_setg(errp, "Can't set node '%s' to r/o with copy-on-read ena= bled", + bdrv_get_device_or_node_name(bs)); + return -EINVAL; + } + bs->read_only =3D read_only; + return 0; } =20 void bdrv_get_full_backing_filename_from_filename(const char *backed, diff --git a/block/bochs.c b/block/bochs.c index bdc2831..a759b6e 100644 --- a/block/bochs.c +++ b/block/bochs.c @@ -110,7 +110,10 @@ static int bochs_open(BlockDriverState *bs, QDict *opt= ions, int flags, return -EINVAL; } =20 - bdrv_set_read_only(bs, true); /* no write support yet */ + ret =3D bdrv_set_read_only(bs, true, errp); /* no write support yet */ + if (ret < 0) { + return ret; + } =20 ret =3D bdrv_pread(bs->file, 0, &bochs, sizeof(bochs)); if (ret < 0) { diff --git a/block/cloop.c b/block/cloop.c index 11f17c8..d6597fc 100644 --- a/block/cloop.c +++ b/block/cloop.c @@ -72,7 +72,10 @@ static int cloop_open(BlockDriverState *bs, QDict *optio= ns, int flags, return -EINVAL; } =20 - bdrv_set_read_only(bs, true); + ret =3D bdrv_set_read_only(bs, true, errp); + if (ret < 0) { + return ret; + } =20 /* read header */ ret =3D bdrv_pread(bs->file, 128, &s->block_size, 4); diff --git a/block/dmg.c b/block/dmg.c index 27ce4a6..900ae5a 100644 --- a/block/dmg.c +++ b/block/dmg.c @@ -419,8 +419,12 @@ 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; + } + block_module_load_one("dmg-bz2"); - bdrv_set_read_only(bs, true); =20 s->n_chunks =3D 0; s->offsets =3D s->lengths =3D s->sectors =3D s->sectorcounts =3D NULL; diff --git a/block/rbd.c b/block/rbd.c index 6ad2904..1c43171 100644 --- a/block/rbd.c +++ b/block/rbd.c @@ -635,13 +635,22 @@ static int qemu_rbd_open(BlockDriverState *bs, QDict = *options, int flags, goto failed_shutdown; } =20 + /* rbd_open is always r/w */ r =3D rbd_open(s->io_ctx, s->name, &s->image, s->snap); if (r < 0) { error_setg_errno(errp, -r, "error reading header from %s", s->name= ); goto failed_open; } =20 - bdrv_set_read_only(bs, (s->snap !=3D NULL)); + /* 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; + } + } =20 qemu_opts_del(opts); return 0; diff --git a/block/vvfat.c b/block/vvfat.c index d4ce6d7..b509d55 100644 --- a/block/vvfat.c +++ b/block/vvfat.c @@ -1156,8 +1156,6 @@ static int vvfat_open(BlockDriverState *bs, QDict *op= tions, int flags, =20 s->current_cluster=3D0xffffffff; =20 - /* read only is the default for safety */ - bdrv_set_read_only(bs, true); s->qcow =3D NULL; s->qcow_filename =3D NULL; s->fat2 =3D NULL; @@ -1169,11 +1167,24 @@ static int vvfat_open(BlockDriverState *bs, QDict *= options, int flags, s->sector_count =3D cyls * heads * secs - (s->first_sectors_number - 1= ); =20 if (qemu_opt_get_bool(opts, "rw", false)) { - ret =3D enable_write_target(bs, errp); + if (!bdrv_is_read_only(bs)) { + ret =3D enable_write_target(bs, errp); + if (ret < 0) { + goto fail; + } + } else { + ret =3D -EPERM; + error_setg(errp, + "Unable to set VVFAT to 'rw' when drive is read-onl= y"); + goto fail; + } + } else { + /* read only is the default for safety */ + ret =3D bdrv_set_read_only(bs, true, &local_err); if (ret < 0) { + error_propagate(errp, local_err); goto fail; } - bdrv_set_read_only(bs, false); } =20 bs->total_sectors =3D cyls * heads * secs; diff --git a/include/block/block.h b/include/block/block.h index 99d49f2..1d7fd19 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -434,7 +434,7 @@ int bdrv_is_allocated_above(BlockDriverState *top, Bloc= kDriverState *base, int64_t sector_num, int nb_sectors, int *pnum); =20 bool bdrv_is_read_only(BlockDriverState *bs); -void bdrv_set_read_only(BlockDriverState *bs, bool read_only); +int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp); bool bdrv_is_sg(BlockDriverState *bs); bool bdrv_is_inserted(BlockDriverState *bs); int bdrv_media_changed(BlockDriverState *bs); --=20 2.9.3