Re: kern/45305: umount says device busy without any process having current directory in the mount or file open

[Matthias Kretschmer <kretschm%cs.uni-bonn.de@localhost>]

Hi

On Tue, Sep 27, 2011 at 01:50:04PM +0000, Christos Zoulas wrote:
>  Do you have a recipe for recreating the problem?

no recipe which is quite worth anything.  I'll stumble upon the problem,
when I update large packages.  I perform compiling of packages inside a
chroot to not have to touch the current installation.  As this iBook
with G3 600MHz (where I have this problem) is quite slow and has not
much disk-space, I perform compiling of packages via a NetBSD/macppc
installation (same userland) hosted on another box which is mounted to
/netboot (basically it is the same installation which is netboot-able).
To speed up compilations I mount_null a /netboot/tmp and
/netboot/wrkobjdir and set PKGSRC_COMPILER to ccache distcc gcc, where
the only DISTCC_HOST is the nfs-host.  So only preprocessing is done
locally.

The problem seems to always occur when I compile www/firefox (including
devel/xulrunner) from pkgsrc HEAD (so last time version 6.0.2).  The
last time, when even the nullfs didn't want to unmount without -f, I was
additionally building chat/ircII.  At the moment I do not have a clue if
creating, opening, writing, reading, or chdir'ing causes this problem
(or a probably parallel combination of all of them).  Even though
writing a test program wouldn't be much work, I have not found the time
to write it...

Are there any counters of open/etc. files for a mount-point?  Am I able
to output these somehow?  As there is no record of anything accessing
the corresponding mount-points I'm wondering why the systems thinks it
is busy.

--
Matthias Kretschmer