Subject: Re: device busy upon mount
To: Zafer Aydogan <firstname.lastname@example.org>
From: Antti Kantee <email@example.com>
Date: 09/11/2007 21:05:56
On Tue Sep 11 2007 at 19:32:57 +0200, Zafer Aydogan wrote:
> > Ah, ok, I found the problem. The real problem, I guess, is that device
> > nodes on layered file systems don't appear to really work.
> > When a layered vnode is initialized, it has a special specinfo structure
> > allocated for it. The specmountpoint field, which is causing EBUSY
> > to be returned, is uninitialized memory (deadbeef on a debug kernel),
> > so this is clearly wrong. If I initialize it to NULL to allow mount to
> > proceed, I get a panic at unmount for dangling buffers.
> > Another point is that layered vnodes don't appear to be considered
> > aliases, although I think they should; at least in the sense that they
> > should share specinfo with all the other nodes in the stack.
> > All this needs a bit more than my next 5min timeslice. For now the best
> > solution is to not null-mount /dev and e.g. mount a second tmpfs for it.
> Excellent. Not null mounting /dev solved all problems.
> I will release a new version with this fix and send a patch to xtraeme.
Cool! Please file a PR about the layerfs problem. I don't have time
to deal with the issue in the coming days.
Antti Kantee <firstname.lastname@example.org> Of course he runs NetBSD
"la qualité la plus indispensable du cuisinier est l'exactitude"