On 29.07.19 18:42, Kevin Wolf wrote:
> scsi-disks decides whether it has a read-only device by looking at
> whether the BlockBackend specified as drive=... is read-only. In the
> case of an anonymous BlockBackend (with a node name specified in
> drive=...), this is the read-only flag of the attached node. In the case
> of an empty anonymous BlockBackend, it's always read-write because
> nothing prevented it from being read-write.
> 
> This is a problem because scsi-cd would take write permissions on the
> anonymous BlockBackend of an empty drive created without a drive=...
> option. Using blockdev-insert-medium with a read-only node fails then
> with the error message "Block node is read-only".
> 
> Fix scsi_realize() so that scsi-cd devices always take read-only
> permissions on their BlockBackend instead.
> 
> Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1733920
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  hw/scsi/scsi-disk.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)

Reviewed-by: Max Reitz <mreitz@redhat.com>