Problem mounting JFFS2 as root, works for ext2

Problem mounting JFFS2 as root, works for ext2

[Dan Cardamore]

Hi,

I'm trying to use a JFFS2 partition as my root file system.

Setup I have:
   - Compact flash connected to an IDE adapter:
      - /dev/hda1 = ext2 with kernel and initrd
      - /dev/hda2 aka /dev/mtdblock/1 is the JFFS2 image
      - /dev/hda3 = ext2, same contents as the JFFS2 image, just a
        differnet fstab
   - GRUB installed on /dev/hda boots using /dev/hda1's kernel and
     initrd.
   - kernel then mounts the real root device

The boot parameters I use for a JFFS2 root are:
blkmtd_device=/dev/hda2 blkmtd_erase=64 devfs=mount root=/dev/mtdblock/1 rw

The boot parameters I use for a JFFS2 root are:
blkmtd_device=/dev/hda2 blkmtd_erase=64 devfs=mount root=/dev/hda3 rw

If I boot using JFFS2 as my root, I get:
<snip>
VFS: Mounted root (jffs2 filesystem)
mount_devfs_fs(): unable to mount devfs, err: -2
Freeing unused kerneel memory: 132k freed
Warning: unable to open an initial console.
Kernel panic: No init found.  Try passing init= option to the kernel

If I boot from /dev/hda3 as my root (ext2), I get everything working
perfect.  Once I have my system up and running, I can then type:
mount -t jffs2 -o rw /dev/mtdblock/1  /mnt
And it works just fine with no warnings.  I can see that the filesystem
has all the contents that the ext2 filesystem has including /dev.  When
I mount it at this point, I can run lsmod and see that zero kernel
modules are loaded since I compiled everything built-in.

So I'm using the same kernel and the same filesystem, just different
root filesystem type.  Does anyone have an idea what could be going on
here?  Any help much appreciated.

Thanks,

Dan

--
Dan Cardamore                              dan.cardamore@officeserver.ca
Cell: (613)355-8048                        http://www.officeserver.ca

Re: Problem mounting JFFS2 as root, works for ext2

[David Woodhouse]

On Sat, 2003-08-09 at 06:33, Dan Cardamore wrote:

> If I boot using JFFS2 as my root, I get:
> <snip>
> VFS: Mounted root (jffs2 filesystem)
> mount_devfs_fs(): unable to mount devfs, err: -2
  <...>
> Warning: unable to open an initial console.
> Kernel panic: No init found.  Try passing init= option to the kernel
> 
> If I boot from /dev/hda3 as my root (ext2), I get everything working
> perfect.

Does it bitch about failing to mount devfs in the case where you mount
ext2-root too?

-- 
dwmw2

Re: Problem mounting JFFS2 as root, works for ext2

[David Woodhouse]

On Sat, 2003-08-09 at 06:33, Dan Cardamore wrote:

> If I boot using JFFS2 as my root, I get:
> <snip>
> VFS: Mounted root (jffs2 filesystem)
> mount_devfs_fs(): unable to mount devfs, err: -2
  <...>
> Warning: unable to open an initial console.
> Kernel panic: No init found.  Try passing init= option to the kernel
> 
> If I boot from /dev/hda3 as my root (ext2), I get everything working
> perfect.

Does it bitch about failing to mount devfs in the case where you mount
ext2-root too?

-- 
dwmw2

Re: Problem mounting JFFS2 as root, works for ext2

[Dan Cardamore]

On Sun, Aug 10, 2003 at 09:27:04AM +0100, David Woodhouse wrote:
> On Sat, 2003-08-09 at 06:33, Dan Cardamore wrote:
> 
> > If I boot using JFFS2 as my root, I get:
> > <snip>
> > VFS: Mounted root (jffs2 filesystem)
> > mount_devfs_fs(): unable to mount devfs, err: -2
>   <...>
> > Warning: unable to open an initial console.
> > Kernel panic: No init found.  Try passing init= option to the kernel
> > 
> > If I boot from /dev/hda3 as my root (ext2), I get everything working
> > perfect.
> 
> Does it bitch about failing to mount devfs in the case where you mount
> ext2-root too?

No, everything boots properly when I ext2.  I should add some more info:
 - When it mounts the jffs2 FS, it does it instantly which means that it
   can't be mounted.  Mounting it properly takes about 20 seconds.
 - In my initrd linuxrc, I can run:
   mount -t jffs2 /dev/mtdblock/1 /
   and it works just fine.  Then the kernel unmouts / and tries to mount
   it again.

I've gotten past the problem by making my /dev/hda1 boot partition a
mini-root with just busybox and it then mounts the JFFS2 partition and
pivot_root's to it.

If anyone has an idea though as to why the kernel can't mount it, I'd
love to skip that kluge.

Thanks,

Dan

--
Dan Cardamore                              dan.cardamore@officeserver.ca
Cell: (613)355-8048                        http://www.officeserver.ca