clone ioctl return values

[Christoph Hellwig]

On Mon, Nov 16, 2015 at 04:28:22PM -0800, Darrick J. Wong wrote:
> >  Try to reflink a device
> > -XFS_IOC_CLONE_RANGE: Invalid argument
> > +/mnt/test/test-157/dev1: No such device or address
> 
> Huh.  How did you get -ENODEV here?  I ran this on 4.3 and got -EINVAL.

This is current 4.4-rc.  The error seems accidental I think.

> Errrgh, the golden output of this test reflects the changes to the input
> checking in Anna/Peng's copy_file_range/clone_file_range patches.
> 
> So, I guess the question is, should I reset the golden output to whatever
> btrfs spits out before that patchset, and we'll consider the alterations
> to be bugs/regressions/whatever that ought to be fixed in their patches?

Some bits in btrfs don't seem kosher.  But it would be good to
explicitly send patches for btrfs to adopt to what might make more
sense, and then follow it in the other implementations.