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

[christos%zoulas.com@localhost (Christos Zoulas)]

On Sep 27,  4:07pm, kretschm%cs.uni-bonn.de@localhost (Matthias Kretschmer) 
wrote:
-- Subject: Re: kern/45305: umount says device busy without any process havin

| 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.

I would start adding printfs in the unmount path in vfs_mount.c following
them down to the one that returns EBUSY...

christos