switch_root and mount move

[Sergey Naumov]

Hello.

Could anyone explain what is the purpose of mount move in switch_root?
>From this answer
(http://lists.busybox.net/pipermail/busybox/2009-June/069609.html) I
got reasons why we need to make chroot AND chdir, but can we do it
without mount move?

My problem is that I want to disable ability to remount root to rw by
rsbac, but I need to call rsbac_init in initramfs after all necessary
mounts are done, so at the time switch_root is called
mounting/remounting of root device is prohibited. Simple chroot works,
but I want to clean initramfs content too.

Thanks in advance,
Sergey Naumov.