name_to_handle_at() and persistent filesystem IDs

Hello Aneesh,

I'm currently working on a man page for name_to_handle_at() and
open_by_handle_at(), and I have a question relating to a point that
probably needs to be covered in the man page.

Back in July 2010, in this thread:
http://thread.gmane.org/gmane.linux.file-systems/41782/focus=43131
you said:

[[
mount id should not be looked at as a persistent identifier. It should
be used to derive a persistent identifier from /proc/self/mountinfo. The
persistent identifier could be the combination of device properties,
file system properties or the uuid which is going to be an optional
tag in /proc/self/mountinfo.
]]

In the man page, I'd like to briefly describe how one derives such a
persistent ID from mountinfo. AFAICS, the optional UUID tag in
/proc/self/mountinfo has not come to pass. So, what then is the
recommended practice for deriving the persistent ID?

Cheers,

Michael

-- 
Michael Kerrisk Linux man-pages maintainer;
http://www.kernel.org/doc/man-pages/
Author of "The Linux Programming Interface", http://blog.man7.org/