deployment: provide LVM support

When using the "ngcplvm" boot option then deployment automatically
sets up LVM (volume group "ngcp" with volumes "root" and "swap"),
otherwise it works just as it used to do so far (AKA no LVM).

Needs performance checks (Kirill volunteered to do that), once
we're happy with the results we can make it the new default
deployment method as planned.

Testing: https://bugtracker.sipwise.com/view.php?id=2465

From: Michael Prokop <mprokop@sipwise.com>

deployment.sh

@@ -57,6 +57,7 @@ HALT=false
 REBOOT=false
 STATUS_DIRECTORY=/srv/deployment/
 STATUS_WAIT=0
+LVM=false
 
 if [ -L /sys/block/vda ] ; then
   export DISK=vda # will be configured as /dev/vda
@@ -328,6 +329,10 @@ if checkBootParam netscript ; then
   NETSCRIPT_SERVER="$(dirname $(getBootParam netscript))"
 fi
 
+if checkBootParam ngcplvm ; then
+  LVM=true
+fi
+
 if checkBootParam ngcpprofile && [ -n "$NETSCRIPT_SERVER" ] ; then
   PROFILE="$(getBootParam ngcpprofile)"
 
@@ -756,15 +761,42 @@ if [ $(awk "/ ${DISK}$/ {print \$3}" /proc/partitions) -gt 2000000000 ] ; then
 else
   TABLE=msdos
 fi
-parted -s /dev/${DISK} mktable "$TABLE"
-# hw-raid with rootfs + swap partition
-parted -s /dev/${DISK} 'mkpart primary ext4 2048s 95%'
-parted -s /dev/${DISK} 'mkpart primary linux-swap 95% -1'
-sync
 
-SWAP_PARTITION="/dev/${DISK}2"
-echo "Initialising swap partition $SWAP_PARTITION"
-mkswap "$SWAP_PARTITION"
+if "$LVM" ; then
+  cat > /tmp/partition_setup.txt << EOF
+disk_config ${DISK} disklabel:${TABLE} bootable:1
+primary -       4096-   -       -
+
+disk_config lvm
+vg ngcp       ${DISK}1
+ngcp-root     /       95%       ext3 rw
+ngcp-swap     swap    5%-10G    swap sw
+EOF
+
+  # make sure setup-storage doesn't fail if LVM is already present
+  dd if=/dev/zero of=/dev/${DISK} bs=1M count=1
+  blockdev --rereadpt /dev/${DISK}
+
+  setup-storage -f /tmp/partition_setup.txt -X
+
+  # used later by installer
+  ROOT_FS="/dev/mapper/ngcp-root"
+  SWAP_PARTITION="/dev/mapper/ngcp-swap"
+
+else # no LVM (default)
+  parted -s /dev/${DISK} mktable "$TABLE"
+  # hw-raid with rootfs + swap partition
+  parted -s /dev/${DISK} 'mkpart primary ext4 2048s 95%'
+  parted -s /dev/${DISK} 'mkpart primary linux-swap 95% -1'
+  sync
+
+  # used later by installer
+  ROOT_FS="/dev/${DISK}1"
+  SWAP_PARTITION="/dev/${DISK}2"
+
+  echo "Initialising swap partition $SWAP_PARTITION"
+  mkswap "$SWAP_PARTITION"
+fi
 
 # otherwise e2fsck fails with "need terminal for interactive repairs"
 echo FSCK=no >>/etc/debootstrap/config
@@ -804,6 +836,13 @@ openssh-server
 #os-prober
 EOF
 
+if "$LVM" ; then
+  cat >> /etc/debootstrap/packages << EOF
+# support LVM
+lvm2
+EOF
+fi
+
 if "$PRO_EDITION" ; then
   cat >> /etc/debootstrap/packages << EOF
 # support 32bit binaries, e.g. for firmware upgrades
@@ -839,18 +878,17 @@ echo y | grml-debootstrap \
   --mirror "$MIRROR" \
   --debopt '--no-check-gpg' $EXTRA_DEBOOTSTRAP_OPTS \
   -r "$DEBIAN_RELEASE" \
-  -t "/dev/${DISK}1" \
+  -t "$ROOT_FS" \
   --password 'sipwise' 2>&1 | tee -a /tmp/grml-debootstrap.log
 
 if [ ${PIPESTATUS[1]} -ne 0 ]; then
-  die "Error during installation of Debian ${DEBIAN_RELEASE}. Find details via: mount /dev/${DISK}1 $TARGET ; ls $TARGET/debootstrap/*.log"
+  die "Error during installation of Debian ${DEBIAN_RELEASE}. Find details via: mount $ROOT_FS $TARGET ; ls $TARGET/debootstrap/*.log"
 fi
 
 sync
-mount /dev/${DISK}1 $TARGET
+mount "$ROOT_FS" "$TARGET"
 
 # provide useable swap partition
-SWAP_PARTITION="/dev/${DISK}2"
 echo "Enabling swap partition $SWAP_PARTITION via /etc/fstab"
 cat >> "${TARGET}/etc/fstab" << EOF
 $SWAP_PARTITION                      none           swap       sw,pri=0  0  0
@@ -1731,6 +1769,12 @@ sync
 # unmount chroot - what else?
 umount $TARGET || umount -l $TARGET # fall back if a process is still being active
 
+if "$LVM" ; then
+  # make sure no device mapper handles are open, otherwise
+  # rereading partition table won't work
+  dmsetup remove_all || true
+fi
+
 # make sure /etc/fstab is up2date
 if ! blockdev --rereadpt /dev/$DISK ; then
   echo "Something on disk /dev/$DISK (mountpoint $TARGET) seems to be still active, debugging output follows:"