Force dismount NFS partitions?

[Brendan Eich]

In article <5415 at fs2.cam.nist.gov>, sims at cam.nist.gov (Jim Sims) writes:
> In article <870 at ki.UUCP> dwatts at ki.UUCP (Dan Watts) writes:
> >Does anyone know of a way to force dismount of an NFS mounted
> >partition?
> 
> Assuming the mounts are hard, the only way I know of to
> force dismounts is to reboot! :=)

Too harsh.  Try umount -k, or fuser -k, or ps and kill/killall.  Provided
the filesystem was mounted with the "intr" option (currently an SGI but not
a Sun default), processes "hung" on it should be killable.

Soft mounts may be undesirable for other reasons (if you're writing to the
filesystem and you want all writes to complete, up till you decide for other
reasons to do the unmount/reboot).

Umount -k calls fuser -k, and fuser may race with a process that opens and
closes a file in the filesystem.  If it loses the race, it won't kill this
busying process.  Note also that 3.3 fuser needs a generous MAXUMEM (which
is defined in /usr/sysgen/master.d/kernel) -- at least as big as physical
memory plus fuser's size.  The default MAXUMEM, 512MB, is more than enough,
but some sites may trim it to prevent resource hogging.  This fuser/MAXUMEM
restriction will be fixed.

/be