[PATCH] xfs: don't hand out pNFS layouts for reflink inodes

[Christoph Hellwig]

On Tue, Mar 29, 2016 at 05:08:42PM -0700, Darrick J. Wong wrote:
> > Btw, we'll need something similar to prevent swapfiles which just use
> > ->bmap, but unfortunately swap just checks for the existences of method,
> > so I'll probably have to do some VFS changes to properly support that.
> 
> Yes, please.  ocfs2 will gladly let you call swapon on a reflinked file,
> and totally fails to CoW it properly. :)

Ouch.  Time to add a test for that to xfstests..