Unable to umount union-parts after umounting unionfs

[Philip Paeps]

On 2005-06-23 10:38:04 (+0200), Jeremie Le Hen <jeremie at le-hen.org> wrote:
> > When playing with union filesystems this morning, I noticed that it's not
> > possible to unmount the directory mounted on union cleanly, even after the
> > union has been cleanly unmounted, once you've read from the union:
> > 
> > [...snip...]
> >
> > Strangely, when an 'empty' union is read from, there's no problem
> > unmounting it.  It's only when it's read when there's something on it.  In
> > other words, from a clean setup:
> > 
> > [...snip...]
> 
> Could you show us the locked vnodes for these two cases please ?

Unfortunately, 'blank' in both cases.  But that might be because I never get
to the debugger 'while' it's unmounting, but always when it has tried and not
succeeded.  (I have WITNESS in my kernel, if that matters?).

Is there any way I can either try to unmount the filesystem manually from the
debugger or make the unmounting code more chatting about what it's waiting
for?

I've had a look through the unionfs and unmount code but filesystems look like
a maze of twisty passages in four dimensions without a map or compass nearby.

Good thing this is perfectly reproducible. :-)

 - Philip

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