Re: 2.4.1 - can't read root fs (devfs maybe?)

Re: 2.4.1 - can't read root fs (devfs maybe?)

[Michael B. Trausch]

On Wed, 31 Jan 2001, Michael J. Dikkema wrote:
> 
> I went from 2.4.0 to 2.4.1 and was surprised that either the root
> filesystem wasn't mounted, or it couldn't be read. I'm using devfs.. I'm
> thinking there might have been a change with regards to the devfs
> tree.. is the legacy /dev/hda1 still /dev/discs/disc0/part1?
> 

First off, are you using ext2fs for your main filesystem (for /)?  If so,
are there any *other* errors?

Also, /dev/hda1 == /dev/ide/host0/bus0/target0/lun0/part1 on my computer,
Kernel 2.4.1, with devfs enabled.  It can also be referenced via another
symlink (/dev/ide/hd/c0b0t0u0p1), which is the same thing.

	- Mike

===========================================================================
Michael B. Trausch                                    fd0man@crosswinds.net
Avid Linux User since April, '96!                           AIM:  ML100Smkr

              Contactable via IRC (DALNet) or AIM as ML100Smkr
===========================================================================

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2.4.1 - can't read root fs (devfs maybe?)

[Michael J. Dikkema]

I went from 2.4.0 to 2.4.1 and was surprised that either the root
filesystem wasn't mounted, or it couldn't be read. I'm using devfs.. I'm
thinking there might have been a change with regards to the devfs
tree.. is the legacy /dev/hda1 still /dev/discs/disc0/part1?

I can't even get a shell with init=/bin/bash.. 

Any help?

Thanks.

,.;::
: Michael J. Dikkema
| Systems / Network Admin - Internet Solutions, Inc.
| http://www.moot.ca   Work: (204) 982-1060
; mjd@moot.ca
',.

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Re: 2.4.1 - can't read root fs (devfs maybe?)

[John Jasen]

On Wed, 31 Jan 2001, Michael J. Dikkema wrote:

> I went from 2.4.0 to 2.4.1 and was surprised that either the root
> filesystem wasn't mounted, or it couldn't be read. I'm using devfs.. I'm
> thinking there might have been a change with regards to the devfs
> tree.. is the legacy /dev/hda1 still /dev/discs/disc0/part1?
>
> I can't even get a shell with init=/bin/bash..

Sounds like a lack of devfsd, which handles backwards compatibility for
/dev entries.

--
-- John E. Jasen (jjasen1@umbc.edu)
-- In theory, theory and practise are the same. In practise, they aren't.

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Re: 2.4.1 - can't read root fs (devfs maybe?)

[Peter Samuelson]

  [Michael J. Dikkema]
> > I went from 2.4.0 to 2.4.1 and was surprised that either the root
> > filesystem wasn't mounted, or it couldn't be read. I'm using devfs.. I'm
> > thinking there might have been a change with regards to the devfs
> > tree.. is the legacy /dev/hda1 still /dev/discs/disc0/part1?
> >
> > I can't even get a shell with init=/bin/bash..

[John Jasen]
> Sounds like a lack of devfsd, which handles backwards compatibility
> for /dev entries.

devfsd does not start up until after the root filesystem is mounted, so
that's not it.

I don't think you can use the /dev/discs/ link for "root=".  It was a
long time ago that I ran into this issue -- but as I recall, links with
'..' in them do not work before the vfs is fully operational.  When I
brought it up with Richard he basically said "don't do that then".

Peter
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Re: 2.4.1 - can't read root fs (devfs maybe?)

[John Jasen]

On Thu, 1 Feb 2001, Peter Samuelson wrote:

>   [Michael J. Dikkema]
> > > I went from 2.4.0 to 2.4.1 and was surprised that either the root
> > > filesystem wasn't mounted, or it couldn't be read. I'm using devfs.. I'm
> > > thinking there might have been a change with regards to the devfs
> > > tree.. is the legacy /dev/hda1 still /dev/discs/disc0/part1?
> > >
> > > I can't even get a shell with init=/bin/bash..
>
> [John Jasen]
> > Sounds like a lack of devfsd, which handles backwards compatibility
> > for /dev entries.
>
> devfsd does not start up until after the root filesystem is mounted, so
> that's not it.

Errrr .... upon careful reading of the devfs/devfsd documentation, you'll
find that it says to put /sbin/devfsd /dev in amongst the first lines in
rc.sysinit.

In looking through rc.sysinit, / is not mounted rw until much later.

--
-- John E. Jasen (jjasen1@umbc.edu)
-- In theory, theory and practise are the same. In practise, they aren't.

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Re: 2.4.1 - can't read root fs (devfs maybe?)

[Peter Samuelson]

[John Jasen]
> Errrr .... upon careful reading of the devfs/devfsd documentation,
> you'll find that it says to put /sbin/devfsd /dev in amongst the
> first lines in rc.sysinit.

> In looking through rc.sysinit, / is not mounted rw until much later.

Who said anything about *re*-mounting '/'?  We are talking about having
trouble mounting '/' the *first* time, i.e. before rc.sysinit ever gets
a chance to run.

How did you expect to run /sbin/devfsd when /sbin doesn't exist yet?

Peter
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Re: 2.4.1 - can't read root fs (devfs maybe?)

[David Ford]

John Jasen wrote:

> On Thu, 1 Feb 2001, Peter Samuelson wrote:
>
> >   [Michael J. Dikkema]
> > > > I went from 2.4.0 to 2.4.1 and was surprised that either the root
> > > > filesystem wasn't mounted, or it couldn't be read. I'm using devfs.. I'm
> > > > thinking there might have been a change with regards to the devfs
> > > > tree.. is the legacy /dev/hda1 still /dev/discs/disc0/part1?
> > > >
> > > > I can't even get a shell with init=/bin/bash..
> >
> > [John Jasen]
> > > Sounds like a lack of devfsd, which handles backwards compatibility
> > > for /dev entries.
> >
> > devfsd does not start up until after the root filesystem is mounted, so
> > that's not it.
>
> Errrr .... upon careful reading of the devfs/devfsd documentation, you'll
> find that it says to put /sbin/devfsd /dev in amongst the first lines in
> rc.sysinit.
>
> In looking through rc.sysinit, / is not mounted rw until much later.

Logic suggests that the root filesystem must be mounted before init runs.  If
init=/bin/bash, no boot scripts are run, devfs should have populated /dev before
the init was spawned.  devfs doesn't depend on the write state of the filesystem.

I am running devfs on 2.4.1, automatically mounted.  I am having no problems.

-d

--
  There is a natural aristocracy among men. The grounds of this are virtue and talents. Thomas Jefferson
  The good thing about standards is that there are so many to choose from. Andrew S. Tanenbaum



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Re: 2.4.1 - can't read root fs (devfs maybe?)

[David Ford]

"Michael J. Dikkema" wrote:

> I went from 2.4.0 to 2.4.1 and was surprised that either the root
> filesystem wasn't mounted, or it couldn't be read. I'm using devfs.. I'm
> thinking there might have been a change with regards to the devfs
> tree.. is the legacy /dev/hda1 still /dev/discs/disc0/part1?

This symlink doesn't exist/isn't usable for boot.  Use the qualified
pathname.

I.e. /dev/discs/disc0/part1 points to /dev/ide/host0/bus0/target0/lun0/part1
on my machine.

Use that pathname.

-d

--
  There is a natural aristocracy among men. The grounds of this are virtue and talents. Thomas Jefferson
  The good thing about standards is that there are so many to choose from. Andrew S. Tanenbaum



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Re: 2.4.1 - can't read root fs (devfs maybe?)

[mirabilos]

----- Original Message ----- 
From: "David Ford" <david@linux.com>
To: "Michael J. Dikkema" <mjd@moot.ca>
Cc: <linux-kernel@vger.kernel.org>
Sent: Thursday, February 01, 2001 11:58 PM
Subject: Re: 2.4.1 - can't read root fs (devfs maybe?)


> "Michael J. Dikkema" wrote:
> 
> > I went from 2.4.0 to 2.4.1 and was surprised that either the root
> > filesystem wasn't mounted, or it couldn't be read. I'm using devfs.. I'm
> > thinking there might have been a change with regards to the devfs
> > tree.. is the legacy /dev/hda1 still /dev/discs/disc0/part1?
> 
> This symlink doesn't exist/isn't usable for boot.  Use the qualified
> pathname.
> 
> I.e. /dev/discs/disc0/part1 points to /dev/ide/host0/bus0/target0/lun0/part1
> on my machine.
> 
> Use that pathname.
> 
> -d

I am used to do "root=0301" on the lilo prompt to avoid that.
Right it works when devfs is mounted at boot (kernel config)
and you change the lilo.conf from:

image=/boot/bzImage
 label=linux
 root=/dev/hda1
 vga=3845

to:

image=/boot/bzImage
 label=linux
 append="root=0301 vga=3845"

or:

image=/boot/bzImage
 label=linux
 append="root=/dev/ide/host0/bus0/target0/lun0/part1 vga=3845"

Maybe the append= thing shortly spoken of in the devfs docu is important.
And at boot time _there are no symlinks_ !!

When init=/bin/bash fails, you prolly have an empty /dev on your root fs
(as usual when doing devfs) and automount _off_. Turn it on.

-mirabilos

-----BEGIN GEEK CODE BLOCK-----
Version: 3.12+(proprietary extensions) # Updated:20010129 nick=mirabilos
GO/S d@ s--: a--- C++ UL++++ P--- L++$(-^lang) E----(joe) W+(++) loc=.de
N? o K? w-(+$) O+>+++ M-- V- PS+++@ PE(--) Y+ PGP t+ 5? X+ R+ !tv(silly)
b++++* DI- D+ G(>++) e(^age) h! r(-) y--(!y+) /* lang=NASM;GW-BASIC;C */
------END GEEK CODE BLOCK------


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Re: 2.4.1 - can't read root fs (devfs maybe?)

[David Ford]

> image=/boot/bzImage
>  label=linux
>  append="root=/dev/ide/host0/bus0/target0/lun0/part1 vga=3845"

root=/dev/ide/host.... will work the same as root=/dev/hda... in pre-devfs

-d

--
  There is a natural aristocracy among men. The grounds of this are virtue and talents. Thomas Jefferson
  The good thing about standards is that there are so many to choose from. Andrew S. Tanenbaum



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Re: 2.4.1 - can't read root fs (devfs maybe?)

[Richard Gooch]

David Ford writes:
> "Michael J. Dikkema" wrote:
> 
> > I went from 2.4.0 to 2.4.1 and was surprised that either the root
> > filesystem wasn't mounted, or it couldn't be read. I'm using devfs.. I'm
> > thinking there might have been a change with regards to the devfs
> > tree.. is the legacy /dev/hda1 still /dev/discs/disc0/part1?
> 
> This symlink doesn't exist/isn't usable for boot.  Use the qualified
> pathname.

Actually, the /dev/ide/hd/... name is available for the root device.

Also, the kernel has special init code to parse /dev/hda1 and similar
names, so they should work too (as long as you don't have "devfs=only"
on your boot line). That's actually very old code (predates devfs).

				Regards,

					Richard....
Permanent: rgooch@atnf.csiro.au
Current:   rgooch@ras.ucalgary.ca