Re: [PATCH] ovl: add ioctls to retrieve layer file descriptors

Miklos Szeredi <[email protected]> Wed, 8 Jul 2026 17:37:40 +0200

Newsgroups	org.kernel.vger.linux-unionfs,org.kernel.vger.linux-api,org.kernel.vger.linux-fsdevel
Message-ID	<CAJfpegtTixwWSh9M-9NbwP0nUbJJ9rh0rxqO7BzgK7Su_RpM+A@mail.gmail.com>

On Wed, 8 Jul 2026 at 16:32, Giuseppe Scrivano <[email protected]> wrote:

> Amir suggested to add that functionality when I've asked for some
> feedback before sending the patch here.  I am fine to drop it if this is
> the consensus although I see its utility from user space.

How about a completely different interface:

int get_fd_opt(const char *name, unsigned int index, unsigned int flags);

Enumerating layers would be as easy as passing an index stating from
zero and stopping when -ERANGE is received.

It would work for all filesystems that use files as options.  No more
fs specific ioctls.

Thanks,
Miklos