Determining process preventing umount of busy partition

[Mel]

On Wednesday 18 February 2009 06:07:52 Polytropon wrote:
> On Tue, 17 Feb 2009 13:30:55 -0900, Mel 
<fbsd.questions at rachie.is-a-geek.net> wrote:
> > This is weird, though. New theories (where are Chase, Cameron and Foreman
> > when you need them!):
>
> Spying around in someone else's house. :-)
>
> > fstat is lying, instead use:
> > fstat -f /usr -m -v
>
> Well, I've taken that pill. This is the result:
>
> 	# /root/bin/fstat -m -v -f /usr
> 	USER     CMD          PID   FD MOUNT      INUM MODE         SZ|DV R/W
> 	# _
>
> It shows NOTHING. I have made a copy of fstat binary in /root/bin,
> which is possible because all needed libs are in /.

Well, that rules that out.

> Furthermore, I've carefully studied the output of "ps ax" and even
> of "top -t", but as well, nothing that indicates some activity on
> /usr...
>
> > You have a mount on top of /usr, ie.: /usr/local or /usr/ports.
>
> No. From /etc/fstab:
>
> 	# Device        Mountpoint              FStype  Options         Dump   
> Pass# # -----------   ---------------------   ------  -------------   -----
>   ----- /dev/ad0s1b     none                    swap    sw              0  
>     0 /dev/ad0s1a     /                       ufs     rw              1    
>   1 /dev/ad0s1d     /tmp                    ufs     rw              2      
> 2 /dev/ad0s1e     /var                    ufs     rw              2       2
> /dev/ad0s1f     /usr                    ufs     rw              2       2
> /dev/ad0s1g     /export/home            ufs     rw              2       2
>
> These are the only partitions on ad0. /usr has its own partition,
> nothing mounted "on top" of it. (You mentioned a valid point: I
> sometimes have another disk mounted inside /export/home, and I
> cannot umount /export/home while this partition is mounted. But
> that's not the case here.)

Can you show mount -p before trying to unmount /usr? On the off-chance /export 
or /export/home is really a symlink to /usr/home (mount -p shows realpath(3) 
for mounts).

> This is REALLY strange, I should get a whiteboard, some pens and
> start making a drawing of the symptoms, until Dr. Cuddy tells me
> not to do so. :-)

Lol, I'm actually enclined to talk to Wilson, since this smells like something 
up his alley (and free lunch).
-- 
Mel

Problem with today's modular software: they start with the modules
    and never get to the software part.