Re: initrd help -- umounts root after pivot_root

From: Chris Lingard (chris_at_ukpost.com)
Date: 10/31/03

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    To: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Date:	Fri, 31 Oct 2003 18:47:47 +0000

    On Friday 31 October 2003 12:18 am, John R Moser wrote:
    > Been trying with 2.4.20, 2.4.22, 2.6.0-test9, how the heck do I get this
    > to work?
    > I set everthing up on /dev/shm type tmpfs, then
    > cd /dev/shm
    > mkdir initrd
    > pivot_root . initrd

    Might be better to do something like:

    mount -t devfs none /dev
    mount -t proc none /proc
    mkdir -p ram
    mount -t tmpfs tmpfs /ram
    cd /ram
    mkdir proc cdrom
    mount -t proc none /ram/proc
    /mount_cdrom

    This is the start of my linuxrc script and creates the future root at /ram

    > Of course, the kernel unmounts / and then swears that it can't find init
    > when the linuxrc exits.
    >
    > The documentation says that linuxrc should pivot_root to the real root in
    > Documentation/initrd.txt so I thought that's what the script sholud do.
    > Apparently the doc is bad/old.

    man pivot_root

    mkdir initrd
    sbin/pivot_root . initrd
    mount devfs -t devfs /dev
    exec /usr/sbin/chroot . /sbin/init <dev/console >dev/console 2>&1

    (These is no automatic call to /sbin/init)

    The documentation is bad insofar as root=/dev/rd/0 now fails

    Also you will need to search for a patch to umount your old /initrd. Please
    feel free you email me direct for a very unofficial patch to linux-2.4.22

    Chris Lingard
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