[RFC][PATCH] device mapper: Add builtin function dm_get_status()

[Christoph Hellwig]

On Thu, Dec 02, 2021 at 09:29:52AM +0000, Roberto Sassu wrote:
> The problem being solved is how to grant access to files
> which satisfy a property defined in the policy.

If you have want to enforce access to files in the block layer using
a specific stacking block driver you don't just have one layering
violation but a bunch of them.  Please go back to the drawing board.