[...]
> Sort of. devfs wouldnt actually make any files on disk -- overmounting
> would only be used for permissions persistence. That is, any file which
> devfs creates is virtual *unless* someone changes permissions on it. Then
> its written to disk. devfs would use the existing permissions if the file
> already exists on disk when devfs is mounted.
Now scap devfs and you have got the same behaviour.
> This way, if the end user never changes permissions, nothing ever touches
> the disk. Think read-only filesystems, or filesystems without 'device
> file' semantics (ntfs, etc.)
Sure, such an "overlay filesystem" would be very nice. But devfs is
something else, completely.
> The alternative way would be to use the "devices.permissions" file as I
> stated in another email. When mounting /dev the kernel opens
> /dev/devices.permissions before placing the file over the mount point.
Much simpler: /etc/rc.d/rc.devices reads it and sets up permissions
accordingly.
> It
> uses that file to store persistence information. This could be overridden
> with a kernel option or mount option to tell it not to store persistent
> information (for e.g. rom filesystems).
> The kernel already does something like this for quotas, doesnt it?
On-disk quotas are limits, in-kernel quotas are actual usages.
-- Horst von Brand vonbrand@sleipnir.valparaiso.cl Casilla 9G, Viņa del Mar, Chile +56 32 672616
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