Subject: Re: problems unmounting an apparently non-busy filesystem
To: NetBSD-current Discussion List <current-users@NetBSD.ORG>
From: Greg A. Woods <>
List: current-users
Date: 04/09/2001 15:43:01
[ On Monday, April 9, 2001 at 12:13:16 (-0700), Charles M. Hannum wrote: ]
> Subject: Re: problems unmounting an apparently non-busy filesystem
> On Mon, Apr 09, 2001 at 03:07:10PM -0400, Greg A. Woods wrote:
> >
> > Does anyone know if there are any hidden reasons why a filesystem would
> > be marked busy even when nothing is apparently using it?
> It may be mmap(2)ed, or there may be some other object left attached to
> it.  Neither of these would show up with fstat(2).

Hmmm....  Is there any long-running system daemon that might mmap() a
file?  Can I find these things with ddb without too much trouble?  What
other objects might be referenced in a filesystem?

That partition, as its name implies, is there basically to use as an
alternate boot disk.  It's current contents are very old NetBSD-1.3I.
Nothing's been done there for a long time and no user files exist

Is it possible that unmount sometimes doesn't completely free up all
objects that might have been used from the parent filesystem?  I've
tried mounting what was /altroot/var on another not-always-busy
fileystem, doing a few file operations in there, then unmounting it and
I'm still able to unmount the parent filesystem again so it's not easily
reproducible if that's the problem.....

							Greg A. Woods

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