The copy_file_range system call seems to be 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.
The FUSE protocol limitations are raised here:
copy_file_range return value on FUSE
<https://lore.kernel.org/all/lhuh5ynl8z5.fsf@oldenburg.str.redhat.com/>
Reviewed-by: Sam James <sam@gentoo.org>
Reviewed-by: Collin Funk <collin.funk1@gmail.com>
