On Tue, Nov 21, 2023 at 08:42:17PM +0100, Miklos Szeredi wrote: > On Tue, 21 Nov 2023 at 02:33, Ian Kent <raven@xxxxxxxxxx> wrote: > > > I've completely lost what we are talking about. > > I started thinking about a good userspace API, and I'm skeptical about > the proposed kernel API being good for userspace as well. > > Maybe something like this would be the simplest and least likely to be > misused (and also very similar to opendir/readdir/closedir): I want batch retrieval to be possible with the kernel interface. That's important for userspace and was requested in the LSFMM discussion. I would like to grab the proposal to return the last mount id in struct mnt_id_req. In userspace it can then easily be implemented the way you proposed below.