clone ioctl return values

[Al Viro]

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.