Add LVM volume group support if lvm_vg= is specified

Support LVM-backed userdata and rootfs partitions via lvm_vg= cmdline
parameter. Activate LVM early in boot process and check for volumes
in the specified volume group. If found, /dev/$vg/userdata is used for
userdata and /dev/$vg/rootfs overrides any systempart= setting.

Author: NotKit

build-initrd.sh

@@ -47,7 +47,7 @@ done
 [ -z $OUT ] && OUT=./out
 
 # list all packages needed for halium's initrd here
-[ -z $INCHROOTPKGS ] && INCHROOTPKGS="initramfs-tools dctrl-tools dmsetup e2fsprogs libc6-dev zlib1g-dev libssl-dev busybox-static parse-android-dynparts"
+[ -z $INCHROOTPKGS ] && INCHROOTPKGS="initramfs-tools dctrl-tools dmsetup e2fsprogs libc6-dev lvm2 zlib1g-dev libssl-dev busybox-static parse-android-dynparts"
 
 BOOTSTRAP_BIN="qemu-debootstrap --arch $ARCH --variant=minbase"
 

debian/control

@@ -13,6 +13,7 @@ Depends: initramfs-tools,
          coreutils,
          busybox-static,
          e2fsprogs,
+         lvm2,
          ${misc:Depends}
 Description: tools for mounting an Ubuntu Touch rootfs
  This package contains the scripts to boot an Ubuntu Touch device.

hooks/halium

@@ -26,6 +26,7 @@ copy_exec /bin/chown /bin
 copy_exec /bin/mount /bin
 copy_exec /sbin/dmsetup /sbin
 copy_exec /sbin/dumpe2fs /sbin
+copy_exec /sbin/lvm /sbin
 copy_exec /lib/$DEB_HOST_MULTIARCH/libz.so.1
 copy_exec /usr/lib/$DEB_HOST_MULTIARCH/libcrypto.so
 copy_exec /usr/lib/$DEB_HOST_MULTIARCH/libdl.so

scripts/halium

@@ -430,36 +430,58 @@ mountroot() {
 	# Make sure the device has been created by udev before we try to mount
 	udevadm settle
 
-	# find the right partition
-	for partname in $partlist; do
-		part=$(find /dev -name $partname | tail -1)
-		[ -z "$part" ] && continue
-		path=$(readlink -f $part)
-		[ -n "$path" ] && break
-	done
+	# Check for LVM volume group in kernel cmdline and activate LVM
+	vg=""
+	if grep -q lvm_vg= /proc/cmdline; then
+		for x in $(cat /proc/cmdline); do
+			case ${x} in
+			lvm_vg=*)
+				vg=${x#*=}
+				;;
+			esac
+		done
+	fi
 
-	# On systems with A/B partition layout, current slot is provided via cmdline parameter.
-	ab_slot_suffix=$(grep -o 'androidboot\.slot_suffix=..' /proc/cmdline | tail -1 | cut -d "=" -f2)
-	if [ -z "$path" ] && [ ! -z "$ab_slot_suffix" ] ; then
-		tell_kmsg "Searching for A/B data partition on slot $ab_slot_suffix."
+	# Activate LVM volume groups if present
+	if [ -n "$vg" ]; then
+		tell_kmsg "Activating LVM volume groups"
+		lvm vgscan --mknodes
+		lvm vgchange -ay
+
+		if [ -n "$vg" ]; then
+			# Check if the volume group actually exists
+			if lvm vgs "$vg" >/dev/null 2>&1; then
+				tell_kmsg "Volume group $vg found"
+			else
+				tell_kmsg "WARNING: Volume group $vg specified but not found"
+				vg=""
+			fi
+		fi
+	fi
 
+	# First check if LVM volume group has userdata
+	if [ -n "$vg" ] && [ -e "/dev/$vg/userdata" ]; then
+		tell_kmsg "Using LVM userdata volume at /dev/$vg/userdata"
+		path="/dev/$vg/userdata"
+	else
+		# Find the right partition for userdata
 		for partname in $partlist; do
-			part=$(find /dev -name "$partname$ab_slot_suffix" | tail -1)
+			part=$(find /dev -name $partname | tail -1)
 			[ -z "$part" ] && continue
 			path=$(readlink -f $part)
 			[ -n "$path" ] && break
 		done
-	fi
 
-	# override with a possible cmdline parameter
-	if grep -q datapart= /proc/cmdline; then
-		for x in $(cat /proc/cmdline); do
-			case ${x} in
-			datapart=*)
-				path=${x#*=}
-				;;
-			esac
-		done
+		# Override with a possible cmdline parameter
+		if grep -q datapart= /proc/cmdline; then
+			for x in $(cat /proc/cmdline); do
+				case ${x} in
+				datapart=*)
+					path=${x#*=}
+					;;
+				esac
+			done
+		fi
 	fi
 
 	if [ -z "$path" ]; then
@@ -517,6 +539,16 @@ mountroot() {
 		fi
 	fi
 
+	# Override systempart with LVM rootfs if volume group is provided
+	if [ -n "$vg" ] && [ -e "/dev/$vg/rootfs" ]; then
+		tell_kmsg "Overriding systempart with LVM rootfs at /dev/$vg/rootfs"
+		_syspart="/dev/$vg/rootfs"
+		# Keep existing options if they were set, otherwise use rw
+		if [ -z "$_syspart_options" ]; then
+			_syspart_options=rw
+		fi
+	fi
+
 	# We need to add the slot suffix to $_syspart for A/B devices
 	if [ -n "$_syspart" ] && [ ! -e "$_syspart" ] && [ ! -z "$ab_slot_suffix" ]; then
 		tell_kmsg "A/B slot system detected! Slot suffix is $ab_slot_suffix"