Sounds like a really good start. Maybe it's even 90% sufficient.
A related problem is that other hung processes will have their current
directories marked as active and/or open. Those processes won't die and so
present an obstacle to unmounting other partitions besides the hung one.
Typically these hung processes will be something along the lines of df(1).
> If some NFS partition cannot be unmounted, can we still force the
> root partition back to R/O status so that it is also marked clean?
There might also be a problem with a scsi device that's disappeared, perhaps
because it was generating errors or perhaps because it was turned off, or...
I would really like to see hot swap capability, too, by the way. I'd like
to be able to move a tape drive between several machines w/o rebooting.
Since they're not all unix, network backups aren't an option.
Stig