Somebody in the thread at some point said:
> there is no "pivot_root" in the fedora-supplied nash script but, near
> the end, there are "setuproot" and "switchroot" commands. are you
> suggesting that one of these is responsible for processing the "root="
> option. after all, *someone* has to process it, i'm just trying to
> figure out who.
These are the magic bits
echo Creating root device.
mkrootdev -t ext3 -o defaults,ro /dev/f8/root
echo Mounting root filesystem.
mount /sysroot
echo Setting up other filesystems.
setuproot
echo Switching to new root and running init.
switchroot
mkrootdev is the guy that actually scans /proc/cmdline for root= (if you
didn't give a partition on the mkrootdev line, which mkinitrd takes care
of on Fedora) and mounts the device mentioned there at /sysroot in the
initrd filesystem. It also makes an entry for it in the initrd
filesystem /etc/fstab.
mkrootdev path
Makes path a block inode for the device which should be
mounted as root. To determine this device nash uses the
device suggested by the root= kernel
command line argument (if root=LABEL is used devices are
probed to find one with that label). If no root=
argument is available, /proc/sys/ker-
nel/real-root-dev provides the device number.
setuproot (undocumented) populates the final root filesystem with
critical mounted goodies according to the initrd /etc/fstab. If there
isn't one, it mounts /sysroot/proc and /sysroot/sys
switchroot is documented:
switchroot newrootpath
Makes the filesystem mounted at newrootpath the new root
filesystem by moving the mountpoint. This will only work
in 2.6 or later kernels.
so switchroot does the pivot_root action with initrd fs /sysroot
(mounted with the mkrootdev device or failing that the kernel root= guy)
-> /
This info is coming from eyeballing the nash sources in the mkinitrd
SRPM, see ./nash/nash.c in there.
> or does the boot-time parm "quiet" toss all that output?
The "setquiet" nash command does that.
setquiet
Cause any later echos in this script to not be displayed.
-Andy
