Re: Question regarding kernel policy: Why ext2 as module?
On Sun, Jul 18, 2004 at 08:58:00PM +1000, Andree Leidenfrost wrote:
> Hi Sven
>
> First of all thanks a lot for your response!
>
> On Sun, 2004-07-18 at 19:32, Sven Luther wrote:
> > On Sun, Jul 18, 2004 at 07:05:20PM +1000, Andree Leidenfrost wrote:
> > [most of my original posting removed]
> > >
> > > I've looked into using a bare-bones cramfs initrd image that would only
> > > load the ext2 module, mount the actual image via the loop device and do
> > > a pivot_root to that. But apart from the fact that it would require
> > > substantial and hard to justify changes upstream, I've really hit a
> > > brickwall because cramfs only supports files < 16MB and my image is
> > > substantially larger (~ 42MB).
> >
> > Could it be possible to boot into a minimal initrd, as one generated by
> > mkinitrd for example, and then use this to mount the larger ramdisk into
> > one of the /dev/ram devices or something, and then pivot_root into this ?
>
> The chief problem seems to be accessing the image for the larger
> ramdisk: If I want to mount it, it needs to be accessible as a file by
> mount. Therefore it needs to be part of the initial (cramfs) initrd
> image. This in turn is where I have a problem because cramfs only
> supports files up to 16MB. Maybe I'm overlooking something very obvious
> here...
Where is all this provided ? On a CD or something such ? Have you looked
at how the liveCD stuff does it ?
> > This should be the same kind of stuff that is already done with the
> > initrd kernels, except you would need to add some script hook to load
> > the ramdisk.
>
> I've looked at the initrd image that comes with the 2.6.6-k7 kernel.
No, look at the mkinitrd manpage and source, not the initrd. In
particular it has hooks to running user selected scripts.
> What linuxrc seems to be doing is resetting the root filesystem to
> what's configured in the kernel. I can't see any use of a secondary
you need to mount the ramdisk somehow, and then pass it the
root=/dev/mem or whatever arg, i think, Not sure, i am no ramdisk
expert.
> ramdisk. Also, I've looked at Debian Installer a few months ago. That
> also uses a ext2 initrd image If I'm not mistaken. Where would I be able
Nope, don't think so.
> to see the use of a secondary ramdisk from within a primary initrd
> image?
No idea.
Friendly,
Sven Luther
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