Re: [PATCH v2] block/blkio: do not use open flags in qemu_open()

["Daniel P. Berrangé" <berrange@redhat.com>]

On Wed, Jul 26, 2023 at 09:48:07AM +0200, Stefano Garzarella wrote:
> qemu_open() in blkio_virtio_blk_common_open() is used to open the
> character device (e.g. /dev/vhost-vdpa-0 or /dev/vfio/vfio) or in
> the future eventually the unix socket.
> 
> In all these cases we cannot open the path in read-only mode,
> when the `read-only` option of blockdev is on, because the exchange
> of IOCTL commands for example will fail.
> 
> In order to open the device read-only, we have to use the `read-only`
> property of the libblkio driver as we already do in blkio_file_open().
> 
> Fixes: cad2ccc395 ("block/blkio: use qemu_open() to support fd passing for virtio-blk")
> Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2225439
> Reported-by: Qing Wang <qinwang@redhat.com>
> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> ---
> 
> Notes:
>     v2:
>     - added comment on top of qemu_open() [Daniel]
>     
>     v1: https://lore.kernel.org/qemu-devel/20230725111155.85426-1-sgarzare@redhat.com/
> 
>  block/blkio.c | 21 ++++++++++++---------
>  1 file changed, 12 insertions(+), 9 deletions(-)

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

With regards,
Daniel
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