Re: [PATCH v3] qcow2: Forbid discard in qcow2 v2 images with backing files

[Alberto Garcia]

On Fri 27 Mar 2020 07:13:04 PM CET, Eric Blake wrote:
>> +for qcow2_compat in 0.10 1.1; do
>> +    echo "# Create an image with compat=$qcow2_compat without a backing 
>> file"
>> +    _make_test_img -o "compat=$qcow2_compat" 128k
>> +
>> +    echo "# Fill all clusters with data and then discard them"
>> +    $QEMU_IO -c 'write -P 0x01 0 128k' "$TEST_IMG" | _filter_qemu_io
>> +    $QEMU_IO -c 'discard 0 128k' "$TEST_IMG" | _filter_qemu_io
>> +
>> +    echo "# Read the data from the discarded clusters"
>> +    $QEMU_IO -c 'read -P 0x00 0 128k' "$TEST_IMG" | _filter_qemu_io
>> +done
>
> Should this loop also inspect qemu-img map output?

I guess we can, although here the image is completely unallocated in
both cases.

Berto