Re: [PATCH RFC v2] fhandle: expose u64 mount id to name_to_handle_at(2)

[Christian Brauner]

> I don't understand what you mean.  If we hand out file handles with

I don't think adding another highly privileged interface in opposition
to exposing the mount id is warranted. The new mount id exposure patch
is a performance improvement for existing use-cases to let userspace
avoid additional system calls. Because as Aleksa showed in the commit
message there's ways to make this race-free right now. The patch hasn't
gained any Acks from Amir or Jeff so it's obviously not going to get
merged. So really, I don't want another interface that goes from
arbitrary superblock to file hidden behind yet another global capability
check.