Bug#778849: Support restoring initrd on shutdown and pivoting into it

[alsauser@pragmasoft.com]

On Fri 07 Apr 2017 12:02:46 +0200, intrigeri wrote:
> /lib/systemd/system/initramfs-shutdown.service:
>     ⋯
> /usr/share/initramfs-tools/initramfs-restore:
>     ⋯
>     /usr/bin/unmkinitramfs /initrd.img "$WORKDIR"
>     ⋯
> /lib/systemd/system-shutdown/initramfs-tools:
>     ⋯
> /usr/share/initramfs-tools/hooks/shutdown:
>     ⋯
>     copy_exec /lib/systemd/systemd-shutdown /shutdown
>     touch $DESTDIR/etc/initrd-release

I was also experiencing improper shutdown of a root filesystem on nvme drives :(  This is a new Bookworm install with the root file system on an LVM thin pool which in turn resides on two nvme drives configured for Raid10 via mdadm.

I tried the suggestion from intrigeri but did not accomplish a successful pivot to initramfs.  I -believe- the problem was that the "mount -o remount,exec /run" occurred too "late" when it was attempted in /usr/lib/systemd/system-shutdown/initramfs-tools.  I moved the "mount -o remount,exec /run" to /usr/share/initramfs-tools/initramfs-restore and was able to get systemd to successfully pivot into the initramfs, and detach all drives ... YMMV :)