On Fri, Mar 06, 2020 at 05:25:49PM +0100, Miklos Szeredi wrote:

On Tue, Mar 03, 2020 at 08:46:09AM +0100, Miklos Szeredi wrote:

quoted

I'm doing a patch.   Let's see how it fares in the face of all these
preconceptions.

Here's a first cut.  Doesn't yet have superblock info, just mount info.
Probably has rough edges, but appears to work.

For starters, you have just made namespace_sem held over copy_to_user().
This is not going to fly.