Re: [Qemu-devel] [PATCH v2 3/3] qemu-iotests: Add 041 backing file chain infinite loop test

[Stefan Hajnoczi <stefanha@redhat.com>]

On Tue, Oct 16, 2012 at 12:22:38PM +0200, Kevin Wolf wrote:
> Am 15.10.2012 14:44, schrieb Stefan Hajnoczi:
> > This new test verifies that qemu-img info --backing-chain safely aborts
> > when an image file has a backing file infinite loop.
> > 
> > Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> > ---
> >  tests/qemu-iotests/041       | 90 ++++++++++++++++++++++++++++++++++++++++++++
> >  tests/qemu-iotests/041.out   | 81 +++++++++++++++++++++++++++++++++++++++
> >  tests/qemu-iotests/common.rc |  9 +++++
> >  tests/qemu-iotests/group     |  1 +
> >  4 files changed, 181 insertions(+)
> >  create mode 100755 tests/qemu-iotests/041
> >  create mode 100644 tests/qemu-iotests/041.out
> > 
> > diff --git a/tests/qemu-iotests/041 b/tests/qemu-iotests/041
> > new file mode 100755
> > index 0000000..839255f
> > --- /dev/null
> > +++ b/tests/qemu-iotests/041
> > @@ -0,0 +1,90 @@
> > +#!/bin/bash
> > +#
> > +# Test that qemu-img info --backing-chain detects infinite loops
> > +#
> > +# Copyright (C) 2012 Red Hat, Inc.
> > +#
> > +# This program is free software; you can redistribute it and/or modify
> > +# it under the terms of the GNU General Public License as published by
> > +# the Free Software Foundation; either version 2 of the License, or
> > +# (at your option) any later version.
> > +#
> > +# This program is distributed in the hope that it will be useful,
> > +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> > +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > +# GNU General Public License for more details.
> > +#
> > +# You should have received a copy of the GNU General Public License
> > +# along with this program.  If not, see <http://www.gnu.org/licenses/>.
> > +#
> > +
> > +# creator
> > +owner=stefanha@redhat.com
> > +
> > +seq=`basename $0`
> > +echo "QA output created by $seq"
> > +
> > +here=`pwd`
> > +tmp=/tmp/$$
> > +status=1	# failure is the default!
> > +
> > +_cleanup()
> > +{
> > +	_cleanup_test_img
> 
> This forgets to remove $TEST_IMG.[123].base.

Thanks for pointing this out.

> > diff --git a/tests/qemu-iotests/041.out b/tests/qemu-iotests/041.out
> > new file mode 100644
> > index 0000000..0c871b0
> > --- /dev/null
> > +++ b/tests/qemu-iotests/041.out
> > @@ -0,0 +1,81 @@
> > +QA output created by 041
> > +Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134217728 
> > +
> > +== backing file references self ==
> > +qemu-img: Aborting due to backing file chain infinite loop.
> > +image: TEST_DIR/t.IMGFMT
> > +file format: IMGFMT
> > +virtual size: 128M (134217728 bytes)
> > +cluster_size: 65536
> > +backing file: TEST_DIR/t.IMGFMT
> 
> I'd expect the error message to be at the end. Should we disable stdout
> buffering completely in qemu-img or add an fflush(stdout)?

This is a special case - we'll also need to carefully terminate the JSON
array.  So a fflush(stdout) with a comment works well.  I will add it.

> Also I think adding a test for JSON mode would make sense.

I'll do that.

Stefan