Re: [Qemu-devel] [PATCH v2] iotests: Filter 175's allocation information

[Nir Soffer]

On Thu, May 16, 2019 at 2:03 PM Max Reitz <address@hidden> wrote:

> On 13.05.19 17:52, Max Reitz wrote:
> > It is possible for an empty file to take up blocks on a filesystem.
> > Make iotest 175 take this into account.
> >
> > Reported-by: Thomas Huth <address@hidden>
> > Signed-off-by: Max Reitz <address@hidden>
> > ---
> > v2: [Nir]
> > - Use a function for filtering
> > - s/empty_blocks/extra_blocks/
> > ---
> >  tests/qemu-iotests/175     | 26 ++++++++++++++++++++++----
> >  tests/qemu-iotests/175.out |  8 ++++----
> >  2 files changed, 26 insertions(+), 8 deletions(-)
> >
> > diff --git a/tests/qemu-iotests/175 b/tests/qemu-iotests/175
> > index d0ffc495c2..b5eb0aa856 100755
> > --- a/tests/qemu-iotests/175
> > +++ b/tests/qemu-iotests/175
> > @@ -28,10 +28,25 @@ status=1  # failure is the default!
> >
> >  _cleanup()
> >  {
> > -     _cleanup_test_img
> > +    _cleanup_test_img
> > +    rm -f "$TEST_DIR/empty"
> >  }
> >  trap "_cleanup; exit \$status" 0 1 2 3 15
> >
> > +# Some file systems sometimes allocate extra blocks independently of
> > +# the file size.  This function hides the resulting difference in the
> > +# stat -c '%b' output.
> > +# Parameter 1: Number of blocks an empty file occupies
> > +# Parameter 2: Image size in bytes
> > +_filter_blocks()
> > +{
> > +    extra_blocks=$1
> > +    img_size=$2
> > +
> > +    sed -e "s/blocks=$extra_blocks/nothing allocated/" \
> > +        -e "s/blocks=$((extra_blocks + img_size / 512))/everything
> allocated/"
>
> Only now got around to creating an FS with similar characteristics to
> Thomas’s.  Turns out this test still fails there because it prints
> “blocks=nothing allocated050”...
>
> Unless objections arise, I’ll just add a \$ to each pattern to fix that.
>  (I could also just swap the lines, but that isn’t really right.)
>

Sounds right.

Can you share how to create file system which reproduces this?
Maybe adding the details in the test would be useful.

Nir