On Fri 27 Mar 2020 03:14:42 PM CET, Kevin Wolf wrote: >> +echo "# Create a backing image and fill it with data" >> +BACKING_IMG="$TEST_IMG.base" >> +TEST_IMG="$BACKING_IMG" _make_test_img 128k >> +$QEMU_IO -c 'write -P 0xff 0 128k' "$BACKING_IMG" | _filter_qemu_io >> + >> +for qcow2_compat in 0.10 1.1; do >> + echo "# Create an image with compat=$qcow2_compat and a backing file" >> + _make_test_img -o "compat=$qcow2_compat" -b "$BACKING_IMG" > > I would write some non-zero data to the backing file so that you can > later distinguish zero clusters from unallocated clusters.
I'm doing that already (immediately before the 'for' loop). I'll add the output of qemu-img map in v3. Berto