Subject: Re: Cloning bdev/cdev devices, step one
To: Bill Studenmund <>
From: Eduardo Horvath <>
List: tech-kern
Date: 07/10/2000 14:21:34
On Mon, 10 Jul 2000, Bill Studenmund wrote:

> [trimmed cc list a little]
> On Mon, 10 Jul 2000, Bill Sommerfeld wrote:
> > > How would you address the biggest concern I've heard with devfs - how to
> > > handle permissions in a persistent manner?
> > 
> > I'd tackle something like that with something which looked vaguely
> > like a union of ffs mounted on top of devfs; the ffs layer would
> > provide the persistance.
> But if the dev_t's are dynamic, how does an ffs provide persistence - how
> would a future boot know what device all of these nodes with permissions
> were for? i.e. how do we preserve some sort of permanent mapping/labeling
> of devices?

The device node was generated by devfs and the name of the device node
was generated by devfs, therefore devfs knows what device that node
corresponds to.  All it has to do is look at the name and repeat whatever
operations it used to generate the name in the first place.

Eduardo Horvath