[systemd-devel] [PATCH 0/6] Patches for a clean shutdown

[Kay Sievers]

On Tue, May 31, 2011 at 17:06,  <harald at redhat.com> wrote:
> This patch series enables a clean disassemble of the
> root device in the shutdown process.
>
> systemd-shutdown checks for /run/initramfs/shutdown, and if found,
> it will pivot_root to /run/initramfs and execute shutdown.

Really cool stuff, which has the potential to solve many of the
problems we have with complex setups below the rootfs.

I guess it's not really obvious to see what it does and why we want this:

On shutdown we 'punch a hole' in /, go through that 'hole' back to the
initramfs / which booted us up.

The rootfs which we ran the system with, is no longer mounted, and
with the same initramfs code which has assembled and mounted the
rootfs originally, we can properly disassemble, shutdown, or logout
the underlying devices.

If no initramfs is used, or it hasn't explicitly kept itself around
during system uptime, it will not be used at shutdown.

Kay