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Re: /dev/.devfsd ?

To: <pjb@xxxxxxxxxxxxxxxxx>
Subject: Re: /dev/.devfsd ?
From: Richard Gooch <rgooch@xxxxxxxxxxxxxxx>
Date: Sat, 4 Aug 2001 09:34:01 -0600
Cc: devfs@xxxxxxxxxxx
In-reply-to: <20010804150859.E72705D622@thalassa.informatimago.com>
References: <20010804112825.9B7F858041@thalassa.informatimago.com> <200108041437.f74Ebh204802@vindaloo.ras.ucalgary.ca> <20010804150859.E72705D622@thalassa.informatimago.com>
Sender: owner-devfs@xxxxxxxxxxx
> > Of course not. You're not supposed to create it. It's created by the
> > kernel. If /dev/.devfsd doesn't exist, it means you haven't mounted
> > devfs on /dev.
> 
> Clearly, there's  something that I've not understood.  Well, from what
> you're writting, I  get it that devfsd and the  stuff done by rc.devfs
> and in rc.sysinit:
> 
>   # If we're using devfs, start devfsd now - we need the old device names
>   [ -e /dev/.devfsd -a -x /sbin/devfsd ] && /sbin/devfsd /dev
> 
> are actually  the devfs_d_aemon stuff  and devfs (which  is integrated
> into the kernel) does not need anything to run, but being mounted. The
> question is : how do you mount a devfs "pseudo-volume" on /dev?

There is a CONFIG option to make devfs mounted at boot time, or you
can do "devfs=mount" at the boot prompt, or you can do:
# mount -t devfs none /dev

Of course, it requires devfs to be compiled into your kernel.

> I've   got   the   problem   with   the   root_fs   distributed   with
> user-mode-linux. For example with the root_fs_redhat_6.2_big, I got:

Which kernel version is this?

> bash# cat /proc/devices
> Character devices:
>   1 mem
>   2 pty
>   3 ttyp
>   4 ttys/%d            <--- aren't they devfs devices ?
>   5 serial/%d          <--- aren't they devfs devices ?

Yes they are. And they shouldn't appear unless CONFIG_DEVFS_FS=y.

> bash# cat /proc/filesystems 
> nodev   proc
> nodev   sockfs
> nodev   tmpfs
> nodev   pipefs
>         ext2
> nodev   devpts
> 
> Why is there no 'nodev devfs' line here?

That's a bloody good question. Also check your dmesg output for devfs
messages:
% dmesg | fgrep devfs

> Perhaps it's the problem, but how to solve it?

For some reason, one part of your kernel thinks it has devfs, the
other part doesn't. Either you've got a strange patch applied, or
perhaps you didn't do a "make dep;make clean" after reconfiguring your
kernel.

                                Regards,

                                        Richard....
Permanent: rgooch@xxxxxxxxxxxxx
Current:   rgooch@xxxxxxxxxxxxxxx

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