Re: kern/43439

[Antti Kantee <pooka%NetBSD.org@localhost>]

The following reply was made to PR kern/43439; it has been noted by GNATS.

From: Antti Kantee <pooka%NetBSD.org@localhost>
To: matthew green <mrg%eterna.com.au@localhost>
Cc: gnats-bugs%netbsd.org@localhost
Subject: Re: kern/43439
Date: Wed, 9 Jun 2010 11:38:41 +0300

 On Wed, Jun 09, 2010 at 06:02:39PM +1000, matthew green wrote:
 > 
 > >  Has this twisty setup ever worked, or should it just be filed under
 > >  "don't do it"?
 > 
 > i've been doing it like this since when ever pkgsrc first gained
 > r/o support, which is a decade or more ago.
 
 Ok, just wanted to verify if this is a new problem (which wasn't
 clear from the original report).
 
 > why is it a twisty setup?
 
 It's first mounting a onto b and then a/dir onto b/dir, where b/dir
 is actually a/dir when "unnullified".  I'd call that twisty and
 generally avoid doing it, but ymmv.
 
 > >  I would solve writable pkgdist by setting DISTDIR in /etc/mk.conf.
 > 
 > that's a pretty crappy solution to something that has worked for a
 > very long time and panics *every* kernel.  (it triggers one of the
 > very few situations that non-LOCKDEBUG kernels complain about.)
 
 Fair enough.
 
 I added ``twistymount'' to tests/fs/nullfs so you can monitor
 progress in fixing this without having to crash your system.
 
 
 On a tangent, atf-run gives me this:
 tc-start: twistymount
 tc-so:panic: rumpuser fatal failure 11 (Resource deadlock avoided)
 tc-end: twistymount, passed
 tp-end: t_basic
 
 Tests which dumped core at least used to fail (I clearly remember
 adding the code to atf to display the reason for failure was a core
 dump).  If upgrading my atf to 0.9 won't fix it, I'll have to file
 an atf PR.  Let's hope this stuff doesn't get more recursive than
 it already is ...