Re: [PATCH] locks: new procfs lockinfo

[Andrew Morton <akpm@linux-foundation.org>]

On Wed, 22 Feb 2012 16:38:27 -0800
ebiederm@xmission.com (Eric W. Biederman) wrote:

> Davidlohr Bueso <dave@gnu.org> writes:
> 
> > From: Davidlohr Bueso <dave@gnu.org>
> >
> > Based on our previous discussion https://lkml.org/lkml/2012/2/10/462 we came to
> > agree on deprecating the current /proc/locks in favor of a more extensible interface.
> > The new /proc/lockinfo file exports similar information - except instead of maj:min the
> > device name is shown - and entries are formated like those in /proc/cpuinfo, allowing us
> > to add new entries without breaking userspace.
> 
> You can't know the device name, attempt to say what you don't know seems
> very dangerous.  It may be reasonable to simply give the deivce number
> and not split the device number into major/minor any more and I am
> concerned about reality.

I don't think we've ever been told any *reason* for switching from
major:minor to device-name.  This is a problem.

And yes, major:minor reliably and uniquely identifies the device.  I'm
not sure that the human-readable string which is largely a convenience
thing is as reliable as this.