clone ioctl return values

[Christoph Hellwig]

On Tue, Nov 17, 2015 at 03:33:20PM +0000, Al Viro wrote:
> On Tue, Nov 17, 2015 at 07:22:52AM -0800, Christoph Hellwig wrote:
> 
> > Yes, I saw that.  So so far I'd suggest something like the following
> > for btrfs:
> > 
> >  - return EBADFD for missing read/wite permissions
> 
> Yowwwch...  What the hell does that have to do with STREAMS?  Or are you
> using EBADFD as "nobody uses that error value anyway, let's assign it
> whatever meaning we need"?
> 
> Besides, that'll be confused with EBADF all the time.  I strongly
> recommend against that.

Yes, I meant EBADF.  That's what we normally use for missing
FMODE_READ/WRITE or fget failures, so why would this call be different
from everything else?