Re: Creating /dev/dk* nodes so as to be persistent

[Alan Barrett <apb%cequrux.com@localhost>]

On Sat, 19 Oct 2013, Thomas Mueller wrote:
> > You can unmount the tmpfs file system:
>
> >         /sbin/umount /dev
>
> I tried that, but /dev/wouldn't umount because device was busy.

Ah, I forgot about that.  "/sbin/umount -f /dev" might work, 
or you can do it in single user mode before the tmpfs /dev is 
mounted.

> I once used NetBSD fsck_ffs on a FreeBSD UFS partition when 
> FreeBSD fsck_ffs didn't work.
>
> That was after building packages in NetBSD with pkgsrc.  It was 
> an old FreeBSD 9.0-BETA1 partition which I still use for FreeBSD 
> ports tree, netbsd-5, netbsd-6, netbsd-HEAD and pkgsrc, and the 
> crash occured under NetBSD.

It's nice that using the same file system partition under both 
FreeBSD and NetBSD usually works, but I'd still be wary of it.

> > I don't think the /dev fixes are high risk.
>
> My idea was to copy temporary /dev in memory to an outside 
> location, then copy back to the USB stick from FreeBSD.
>
> But I could try from NetBSD-current i386 on another 16 GB USB 
> stick, or from NetBSD 6.1-STABLE on the other computer.

There's not much point in copying from the tempfs /dev and then 
copying back; it's much easier to just build a new /dev in an 
empty directory, assuming you haven't done much to customise the 
permissions or file names or other aspects of /dev.  If copying 
things under some other OS is part of the possible solution, then 
I'd create and populate a /dev.new directory, and then rename it 
into place, like this:

    On the NetBSD machine that has the problem:

        mkdir /dev.new;
        cp -p /dev/MAKEDEV* /dev.new/;
        cd /dev.new; ./MAKEDEV ALL; ./MAKEDEV dk16 dk17 dk18 dk19;

    On some other machine that can mount that disk as /mnt:

        mv /mnt/dev /mnt/dev.old;
        mv /mnt/dev.new /mnt/dev;

    Later, delete the /dev.old directory.

--apb (Alan Barrett)