The following reply was made to PR kern/32112; it has been noted by GNATS.

From: Jed Davis <jld@NetBSD.org>
To: gnats-bugs@NetBSD.org
Cc: 
Subject: Re: kern/32112
Date: Sat, 22 Apr 2006 18:54:09 -0400

 I've also seen the false "device busy" when installing a system onto
 a mountpoint (and so creating device nodes there), with nothing I nor
 fstat/lsof can see that would busy the FS.
 
 I also just got the "does not match mounted device" on a system where I
 mount an mfs on /dev on boot -- I couldn't mount -u a filesystem that
 was mounted before the change of /dev.
 
 My suspicion is that this is a problem with the practice of internally
 referring to devices by vnode pointers instead of device numbers -- in
 the first case, the dev-to-vp mapping winds up picking up the wrong
 vnode given a choice between several with the same number; and in the
 second, it's not seeing that the two device nodes really are the same,
 even though one is on ffs and the other mfs.