On Fri, Mar 18, 2022 at 04:36:44PM -0400, John Snow wrote:
> qemu-io fails on read/write with zero-length raw images, so skip these
> when running the zero-length image tests.
On my first read, I wondered what we accomplish by rejecting
zero-length reads on a zero-length image, and whether entering the
rabbit hole of trying to make that corner case "work" differently
makes more sense...
>
> Signed-off-by: John Snow <js...@redhat.com>
> ---
> tests/qemu-iotests/040 | 14 ++++++++++++--
> 1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/tests/qemu-iotests/040 b/tests/qemu-iotests/040
> index adf5815781..c4a90937dc 100755
> --- a/tests/qemu-iotests/040
> +++ b/tests/qemu-iotests/040
> @@ -86,8 +86,10 @@ class TestSingleDrive(ImageCommitTestCase):
> qemu_img('create', '-f', iotests.imgfmt,
> '-o', 'backing_file=%s' % mid_img,
> '-F', iotests.imgfmt, test_img)
> - qemu_io('-f', 'raw', '-c', 'write -P 0xab 0 524288', backing_img)
> - qemu_io('-f', iotests.imgfmt, '-c', 'write -P 0xef 524288 524288',
> mid_img)
> + if self.image_len:
> + qemu_io('-f', 'raw', '-c', 'write -P 0xab 0 524288', backing_img)
> + qemu_io('-f', iotests.imgfmt, '-c', 'write -P 0xef 524288
> 524288',
> + mid_img)
...but now it is obvious - one of our test cases is attempting a
non-zero-length modification to a zero-length file, and it does make
sense for that modification attempt to fail, in which case, making the
test special case the zero-length file is the right thing to do.
Reviewed-by: Eric Blake <ebl...@redhat.com>
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
