Re: [PATCH] vfs: return EOPNOTSUPP when ioctl_fsthaw() is not supported

[Christoph Hellwig]

On Sun, Dec 18, 2016 at 06:57:27PM +0000, Sami Kerola wrote:
> An attempt to freeze a filesystem that does not support such operation is
> reported as EOPNOTSUPP to user.  Running unfreeze to the same filesystem
> returns EINVAL.  Later is a little misleading, users can mix that message
> with return value from unfreezing when filesystem is not frozen.

This is going to break gfs2 with it's odd ->that_super method.