clone ioctl return values

[Chris Mason]

On Tue, Nov 17, 2015 at 07:22:52AM -0800, Christoph Hellwig wrote:
> On Tue, Nov 17, 2015 at 08:57:45AM -0500, Chris Mason wrote:
> > > > 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.
> > 
> > Btrfs does check for directories, but we should really be checking for
> > regular files too.  In the end, we only copy extents that would
> > correspond with regular files, so we're sneaking by.
> 
> Yes, I saw that.  So so far I'd suggest something like the following
> for btrfs:
> 
>  - return EBADFD for missing read/wite permissions

Why not -EPERM?  I don't have strong feelings about picking errnos, as
long as we're consistent, I'm not worried.

>  - return EINVAL for wrong non-directory file types as the
>    source fd

Ack.

-chris