unmounting a volume

[Gerald Combs]

Duane Attaway wrote:
> What do you do when you want to unmount a volume, but its BUSY by some
> nonexistant process?
> 
> I had a USB drive mounted and the drive went into suspend.  It doesn't
> wake up properly with this kernel and unmounting hangs the command line.
> Syncing hangs too.  Unmounting with the -f option tells me umount is
> also busy?!
> 
> root at dattaway dattaway # umount /v -f
> 
> umount2: Device or resource busy
> umount: /v: device is busy
> 
> root at dattaway dattaway # fuser /v
> /v:
> 
> The only thing I know how to do at this point is to guess and start
> killing processes all the way to init.  There has to be a better way.

Does lsof work?  It probably uses the same method as fuser, but it's
worth a shot.  You could also look in /proc/[0-9]*/fd/ for any links
pointing to /v.