[LTP] [PATCH] syscalls/copy_file_range02.c: Compatible with new and old kernels

[Cyril Hrubis <chrubis@suse.cz>]

Hi!
> I have no objection on this. But, is there really make sense to test some
> more non regular files which not being mentioned by Linux Manual Page?
> 
> The copy_file_range02 test errors are all extract from manual page, I
> commented that in Christian's first patch version. And I don't think it's
> necessary to test undefined behavior in syscall using, because how do we
> know what error return is the expected?

That's not undefined that's undocummented at best. The kernel code for
vfs_copy_file_range does:

        if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode))
                return -EISDIR;
        if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode))
                return -EINVAL;

Which means that directories are treated as special here and all other file
descriptors that are not regular files are supposed to fail with EINVAL.

So as far as I can tell it makes sense to pass a pipe fd for example and check
for EINVAL. And we should do that both for in_fd and out_fd as well.

-- 
Cyril Hrubis
chrubis@suse.cz