[PATCH] Linux: Add test case for bug 33245

[Florian Weimer]

* Yury Khrustalev:

> This comparison fails on Debian 13 with recent kernel 6.12.48+deb13-arm64
> (it works fine on 6.12.43+deb13-arm64) for copy sizes like 0xfffff001,
> for example:
>
> ../sysdeps/unix/sysv/linux/tst-copy_file_range-large.c:173: numeric comparison failure
>    left: 4294963200 (0xfffff000); from: copied
>   right: 4294963201 (0xfffff001); from: size

Is this a 64-bit build?

> I can't find changelog for 6.12.48+deb13 right now, but reading man page
> for copy_file_range() I can see that it can copy less number of files than
> requested and it should not be an error. Is there anything in this test
> that should force copy_file_range() to always copy as many bytes as
> requested?

Yes, the FUSE layer (or the VFS?) was changed after I reported this to
the FUSE maintainers.  Previously the code path to the FUSE callback was
completely clean and no such shortening could happen.

I realized that this would lead to a test suite failure, but have not
had the time to adjust it proactively.

Thanks,
Florian