some errors when extend LV for root filesystem.

When daily packages update, those toubles happened. I updated latest linux-image-3.0.0 for Sid/VirtualBox, but failed that. The cause was that capasity of root file system was not enough. I added SATO virtual disk to the VM, I booted from rescue mode of netinst Debian system, did not mount any devices as root file system, executed follow procedure in rescue mode shell.

# fdisk /dev/sdb # make a new slice(/dev/sdb1) as LVM
# pvcreate /dev/sdb1
# vgextend hogevg /dev/sdb1
# lvextend -l +20 /dev/hogevg/root
# e2fsck -f /dev/hogevg/root
# resize2fs /dev/hogevg/root
# exit

I rebooted, then VM poweroff and dettach netinst.iso, power on VM.

This boot was successful, I updated deb packes and reboot again. But next boot failed on the way. The new initramfs cannot find a device of root file system. I forgot to add the new device file to /boot/grub/ Then, I fallback to a snapshot of pre-updating, executed previous procedures without reboot kernel, and executed below procedures finally.

# grub-mdevicemap
# update-initramfs -u -k 3.0.0-1-amd64
# update-grub2
# shutdown -r now