From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53415) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cvqQF-0002DS-1J for qemu-devel@nongnu.org; Wed, 05 Apr 2017 15:16:52 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cvqQD-00077y-S0 for qemu-devel@nongnu.org; Wed, 05 Apr 2017 15:16:51 -0400 References: From: John Snow Message-ID: <5b1d70c3-7319-9dd1-7693-45f2c1e762a9@redhat.com> Date: Wed, 5 Apr 2017 15:16:38 -0400 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH for-2.10 2/9] block: do not set BDS read_only if copy_on_read enabled List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jeff Cody , qemu-devel@nongnu.org Cc: kwolf@redhat.com, stefanha@redhat.com, qemu-block@nongnu.org On 04/05/2017 02:28 PM, Jeff Cody wrote: > 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. > > Signed-off-by: Jeff Cody > --- > block.c | 10 +++++++++- > block/bochs.c | 5 ++++- > block/cloop.c | 5 ++++- > block/dmg.c | 6 +++++- > block/rbd.c | 6 +++++- > block/vvfat.c | 15 ++++++++++++--- > include/block/block.h | 2 +- > 7 files changed, 40 insertions(+), 9 deletions(-) > > diff --git a/block.c b/block.c > index 7b4c7ef..f60d5ea 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, "Cannot set node '%s' to r/o while COW enabled", COW? > + 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..328e4a9 100644 > --- a/block/rbd.c > +++ b/block/rbd.c > @@ -641,7 +641,11 @@ static int qemu_rbd_open(BlockDriverState *bs, QDict *options, int flags, > goto failed_open; > } > > - bdrv_set_read_only(bs, (s->snap != NULL)); > + r = bdrv_set_read_only(bs, (s->snap != NULL), &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..34a2854 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; > @@ -1173,7 +1171,18 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags, > if (ret < 0) { > goto fail; > } > - bdrv_set_read_only(bs, false); > + ret = bdrv_set_read_only(bs, false, &local_err); > + if (ret < 0) { > + error_propagate(errp, local_err); > + 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; > + } > } > > 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); >