On Tue, 21 Oct 1997, Colin Wood wrote:

> David A. Gatwood wrote:
> > 
> > Speaking of buffer cache, I've run into a weird bug.  A few months ago
> > (mid april, I think?), Allen Briggs compiled an ncrscsi kernel for my
> > laptop (PB145 from h*ll), with the hardware-based adb driver and the
> > intvid code to handle its video.  Anyway, it greatly decreased, but didn't
> > eliminate the fs damage.  I have found something that does, however.  When
> > I shut down, if I manually sync several times and unmount each partition
> > except /, then go to single-user, then sync several times, then mount -o
> > ro /, then shutdown -h or -r now, I don't get any fs corruption.  However,
> > when I just do a shutdown -h or -r now from multi-user mode, the root fs
> > is seriously damaged.  (The others are so small, and so infrequently used
> > that they don't usually get hurt.)  Does anyone have any idea what could
> > cause this?
> 
> My only guess is that your PowerBook is managing to power off before

Except that NetBSD isn't able to power it off, at least with the kernel
I'm using.

> syncing the disks fully.  Is the full procedure you describe really
> necessary?  In other words, I think that the following should accomplish
> the same thing:
> 
> 1) 'shutdown now' to go single user
> 2) 'sync'
> 3) 'umount -a'  (although I want to say this may not get the root
> device...I'll have to read the man page to be sure).

I didn't think that would work for root, since it has to be remounted
read-only...

> 4) 'shutdown -h now'
> 
> How does that work?

That works fine.  I wasn't aware of umount -a working for the root fs.
Actually, I've thought of one more factor... as far back as I can
remember, I've had problems when using shutdown -r now.  I don't recall
whether shutdown -h now causes the problem or not, now that I think about
it -- which makes sense, since -r does reboot, while -h basically
approximates "it is now safe to shut of your macintosh"....

I'm trying a shutdown -h now from multi-user, rebooting from its prompt,
booting NetBSD....  No problems whatsoever....  Therefore, it seems to
only happen with a shutdown -r now....


David

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