[PATCH] Linux: Add test case for bug 33245

[Florian Weimer]

* Sam James:

> Florian Weimer <fweimer@redhat.com> writes:
>
>> The copy_file_range system call seems the only one that can return
>> an off64_t value.  Use FUSE to exercise this, without actually
>> creating such large files or copying any data.  Due to FUSE protocol
>> limitations, only sizes up to UINT_MAX can be tested, but this is
>> sufficient to check for the presence of bug 33245.
>
> Reviewed-by: Sam James <sam@gentoo.org>

Thanks, but there were a few glitches with this patch.  I think we can
test a few values more, and the cancellation settings weren't correct.

The FUSE protocol is not a good fit for copy_file_range.  I sent a note
to the FUSE project and the kernel developers:

  copy_file_range return value on FUSE
  <https://lore.kernel.org/linux-api/lhuh5ynl8z5.fsf@oldenburg.str.redhat.com/>

Florian