From patchwork Fri Apr 7 20:55:26 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Cody X-Patchwork-Id: 748459 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3w0BlH62j8z9ryr for ; Sat, 8 Apr 2017 06:59:07 +1000 (AEST) Received: from localhost ([::1]:52547 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cwayH-0008Ea-A2 for incoming@patchwork.ozlabs.org; Fri, 07 Apr 2017 16:59:05 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50554) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cwavE-00065S-Li for qemu-devel@nongnu.org; Fri, 07 Apr 2017 16:55:58 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cwavD-0003Sx-Fl for qemu-devel@nongnu.org; Fri, 07 Apr 2017 16:55:56 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36824) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cwav6-0003Lf-IU; Fri, 07 Apr 2017 16:55:48 -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 78E7761976; Fri, 7 Apr 2017 20:55:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 78E7761976 Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=jcody@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 78E7761976 Received: from localhost (ovpn-116-76.phx2.redhat.com [10.3.116.76]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7F6455C88B; Fri, 7 Apr 2017 20:55:43 +0000 (UTC) From: Jeff Cody To: qemu-devel@nongnu.org Date: Fri, 7 Apr 2017 16:55:26 -0400 Message-Id: <0c5b4c1cc2c651471b131f21376dfd5ea24d2196.1491597120.git.jcody@redhat.com> In-Reply-To: References: In-Reply-To: References: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Fri, 07 Apr 2017 20:55:47 +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 v2 for-2.10 2/8] 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: kwolf@redhat.com, jsnow@redhat.com, stefanha@redhat.com, qemu-block@nongnu.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" 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=vvfat,dir=/tmp/vvfat,rw,if=virtio,readonly=on" This is not correct. Now, attempting to use the above -drive parameter will result in an error (i.e., 'rw' is incompatible with 'readonly=on'). Signed-off-by: Jeff Cody --- 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 7b4c7ef..c9eb613 100644 --- a/block.c +++ b/block.c @@ -192,9 +192,17 @@ void path_combine(char *dest, int dest_size, } } -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 enabled", + bdrv_get_device_or_node_name(bs)); + return -EINVAL; + } + bs->read_only = read_only; + return 0; } 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 *options, int flags, return -EINVAL; } - bdrv_set_read_only(bs, true); /* no write support yet */ + ret = bdrv_set_read_only(bs, true, errp); /* no write support yet */ + if (ret < 0) { + return ret; + } ret = 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 *options, int flags, return -EINVAL; } - bdrv_set_read_only(bs, true); + ret = bdrv_set_read_only(bs, true, errp); + if (ret < 0) { + return ret; + } /* read header */ ret = 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 *options, int flags, return -EINVAL; } + ret = bdrv_set_read_only(bs, true, errp); + if (ret < 0) { + return ret; + } + block_module_load_one("dmg-bz2"); - bdrv_set_read_only(bs, true); s->n_chunks = 0; s->offsets = s->lengths = s->sectors = s->sectorcounts = 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; } + /* rbd_open is always r/w */ r = 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; } - bdrv_set_read_only(bs, (s->snap != NULL)); + /* If we are using an rbd snapshot, we must be r/o, otherwise + * leave as-is */ + if (s->snap != NULL) { + r = bdrv_set_read_only(bs, true, &local_err); + if (r < 0) { + error_propagate(errp, local_err); + goto failed_open; + } + } 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 *options, int flags, s->current_cluster=0xffffffff; - /* read only is the default for safety */ - bdrv_set_read_only(bs, true); s->qcow = NULL; s->qcow_filename = NULL; s->fat2 = NULL; @@ -1169,11 +1167,24 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags, s->sector_count = cyls * heads * secs - (s->first_sectors_number - 1); if (qemu_opt_get_bool(opts, "rw", false)) { - ret = enable_write_target(bs, errp); + if (!bdrv_is_read_only(bs)) { + ret = enable_write_target(bs, errp); + if (ret < 0) { + goto fail; + } + } else { + ret = -EPERM; + error_setg(errp, + "Unable to set VVFAT to 'rw' when drive is read-only"); + goto fail; + } + } else { + /* read only is the default for safety */ + ret = bdrv_set_read_only(bs, true, &local_err); if (ret < 0) { + error_propagate(errp, local_err); goto fail; } - bdrv_set_read_only(bs, false); } bs->total_sectors = cyls * heads * secs; diff --git a/include/block/block.h b/include/block/block.h index 06c9032..beb563a 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -426,7 +426,7 @@ int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base, int64_t sector_num, int nb_sectors, int *pnum); 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);