Re: [PATCH 12/16] tests: validate dmsetup result in test 128

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

On Tue, May 12, 2026 at 08:53:47AM -0700, Pierrick Bouvier wrote:
> On 4/24/2026 8:42 AM, Daniel P. Berrangé wrote:
> > The I/O test 128 uses 'dmsetup create' to create a device, optionally
> > using sudo to elevate privileges.
> > 
> > This dmsetup command works in GitLab CI, however, the test then fails
> > with a missing device name:
> > 
> >   1..1
> >   # running raw 128
> >   not ok raw 128
> >   ----------------------------------- stderr -----------------------------------
> >   --- /builds/berrange/qemu/tests/qemu-iotests/128.out
> >   +++ /builds/berrange/qemu/build/scratch/raw-file-128/128.out.bad
> >   @@ -1,5 +1,5 @@
> >    QA output created by 128
> > 
> >    == reading from error device ==
> >   -read failed: Input/output error
> >   +qemu-io: can't open device /dev/mapper/eiodev16546: Could not open '/dev/mapper/eiodev16546': No such file or directory
> >    *** done
> > 
> >   (test program exited with status code 1)
> > 
> > It is believed that this is due to the build env using a manually
> > populated /dev, such that the device mapper node won't ever appear.
> > It is not a race, since a test adding a sleep did not result in the
> > device appearing.
> >
> 
> Could that be related to the fact it's running inside a container (if it
> is). Maybe it's just missing exposing all /dev instead of a limited set
> of devices.

We don't have any control over what's present in /dev in test environments,
so we shouldn't assume /dev automatically exposes devices that we can
create via device mapper, as it could be locked down.

> 
> > Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> > ---
> >  tests/qemu-iotests/128 | 6 ++++++
> >  1 file changed, 6 insertions(+)
> > 
> > diff --git a/tests/qemu-iotests/128 b/tests/qemu-iotests/128
> > index d0e00d24b1..d75b1a451a 100755
> > --- a/tests/qemu-iotests/128
> > +++ b/tests/qemu-iotests/128
> > @@ -42,6 +42,12 @@ _setup_eiodev()
> >  		echo "0 $((1024 * 1024 * 1024 / 512)) error" | \
> >  			$cmd dmsetup create "$devname" 2>/dev/null
> >  		if [ "$?" -eq 0 ]; then
> > +			DEV="/dev/mapper/$devname"
> > +			if ! -e $DEV
> > +			then
> > +				_notrun "Device $DEV not appearing"
> > +			fi
> > +
> >  			sudo="$cmd"
> >  			return
> >  		fi
> 

With regards,
Daniel
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