Robert Siemer writes:
> Until today I was clueless what the difference between
> "Permissions database stored in mounted-over /dev" and
> "Permissions database stored in normal directory" is.
> Main problem was missing documentation of "mount --bind" as my old
> mount man page did not mentioned it. I upgraded "mount" but "--bind"
> is still missing in the man page. Just the command on its own gave a
Complain to Andries to get the man page fixed.
> One can also mount an already visible directory tree elsewhere:
> mount --bind olddir newdir
> Now I see the difference in both mentioned approaches - there is
> nearly no one!
> In the end (everything is mounted) both solution have their database
> in /dev-state and devfs in (e.g.) /dev.
> While unmounted you can see it this way:
> mounted-over /dev:
> -/dev is holding the database (and mountpoint, too)
> -/dev-state is empty (mountpoint only)
> normal directory:
> -/dev is empty (mountpoint only)
> -/dev-state is holding the database
> I hope I'm correct here...
> And as "mounted-over /dev" needs a new mount and recent kernel:
> what's its gain?
- You don't need to copy inodes from /dev to /dev-state
- you can seamlessly switch between devfs and non-devfs systems
without worrying about copying permissions over.