Merge branch 'lvm' into 'main'

add LVM support for root partition

See merge request alpine/cloud/tiny-cloud!146

README.md

@@ -49,6 +49,7 @@ IMDS data.
 As Tiny Cloud is meant to be tiny, it has few dependencies:
 * Busybox (`ash`, `wget`, etc.)
 * `e2fsprogs-extra` (for `resize2fs`)
+* `lvm2` (for resizing LVM volumes)
 * `openssh-server`
 * `partx`
 * `sfdisk`

TODO.md

@@ -20,7 +20,7 @@
 
 * Support for `#network-config`?
 
-* Support LVM partitioning and non-`ext[234]` filesystems?
+* Support non-`ext[234]` filesystems?
 
 * Support other cloud providers...
   * IBM

lib/tiny-cloud/init

@@ -38,6 +38,7 @@ init__expand_root() {
 	local dev=$(awk '$2 == "/" {print $1}' "$PROC"/mounts 2>/dev/null)
 	local filesystem=$(awk '$2 == "/" {print $3}' "$PROC"/mounts 2>/dev/null)
 	local partition=$(cat "$SYS/class/block/${dev#/dev/}/partition" 2>/dev/null)
+	local is_lvm=0
 
 	# only support ext2/ext3/ext4 for now
 	case "$filesystem" in
@@ -45,14 +46,53 @@ init__expand_root() {
 		*) return;;
 	esac
 
-	if [ -n "$partition" ]; then
-		# it's a partition, resize it
-		local volume=$(readlink -f "$SYS/class/block/${dev#/dev/}/..")
-		volume="/dev/${volume##*/}"
-		echo ", +" | $MOCK sfdisk -q --no-reread -N "$partition" "$volume"
-		$MOCK partx -u "$volume"
+	# check if this is an LVM logical volume
+	if [ -L "$dev" ] && readlink -f "$dev" | grep -q "/dev/mapper/"; then
+		is_lvm=1
+	elif echo "$dev" | grep -q "^/dev/mapper/"; then
+		is_lvm=1
+	elif echo "$dev" | grep -q "^/dev/[^/]*/[^/]*"; then
+		# format like /dev/vg/lv
+		is_lvm=1
 	fi
-	# resize filesystem
+
+	if [ "$is_lvm" -eq 1 ]; then
+		# LVM volume detected
+		# find the physical volume backing this LV
+		local vg_name=$(lvs --noheadings -o vg_name "$dev" 2>/dev/null | tr -d ' ')
+		local pv_dev=$(pvs --noheadings -o pv_name -S "vg_name=$vg_name" 2>/dev/null | tr -d ' ' | head -n1)
+
+		if [ -n "$pv_dev" ]; then
+			# get the partition number if PV is on a partition
+			local pv_partition=$(cat "$SYS/class/block/${pv_dev#/dev/}/partition" 2>/dev/null)
+
+			if [ -n "$pv_partition" ]; then
+				# resize the partition containing the PV
+				local pv_volume=$(readlink -f "$SYS/class/block/${pv_dev#/dev/}/..")
+				pv_volume="/dev/${pv_volume##*/}"
+				echo ", +" | $MOCK sfdisk -q --no-reread -N "$pv_partition" "$pv_volume"
+				$MOCK partx -u "$pv_volume"
+			fi
+
+			# resize the physical volume
+			$MOCK pvresize "$pv_dev"
+
+			# extend the logical volume
+			# leave 15% for snapshots
+			$MOCK lvextend -l +85%VG "$dev"
+		fi
+	else
+		# standard partition handling (non-LVM)
+		if [ -n "$partition" ]; then
+			# it's a partition, resize it
+			local volume=$(readlink -f "$SYS/class/block/${dev#/dev/}/..")
+			volume="/dev/${volume##*/}"
+			echo ", +" | $MOCK sfdisk -q --no-reread -N "$partition" "$volume"
+			$MOCK partx -u "$volume"
+		fi
+	fi
+
+	# resize filesystem (common for both LVM and non-LVM)
 	if [ -e "$dev" ] || [ -n "$MOCK" ]; then
 		$MOCK resize2fs "$dev"
 	fi

tests/init.test

@@ -11,6 +11,8 @@ lib="$srcdir"/lib/tiny-cloud/init
 init_tests \
 	expand_root \
 	expand_root_partition \
+	expand_root_lvm_partition \
+	expand_root_lvm_whole_disk \
 	ethernets \
 	find_first_interface_up \
 	auto_detect_ethernet_interface \
@@ -69,6 +71,75 @@ expand_root_partition_body() {
 	done
 }
 
+expand_root_lvm_partition_body() {
+	# Test LVM on a partition (e.g., /dev/sda2 -> PV -> VG -> LV)
+	mkdir -p proc sys/class/block \
+		sys/devices/pci0000:00/0000:00:05.0/virtio2/block/vda/vda2 \
+		sys/devices/pci0000:00/0000:00:05.0/virtio2/block/vda/device \
+		dev/mapper
+	ln -s ../../devices/pci0000:00/0000:00:05.0/virtio2/block/vda sys/class/block/vda
+	ln -s ../../devices/pci0000:00/0000:00:05.0/virtio2/block/vda/vda2 sys/class/block/vda2
+	echo 2 > sys/class/block/vda2/partition
+
+	# Create fake LVM device
+	mkdir -p sys/class/block/dm-0
+	ln -s /dev/mapper/vg0-root dev/mapper/vg0-root
+
+	# Mock LVM commands
+	fake_bin lvs <<-EOF
+		#!/bin/sh
+		echo "  vg0"
+	EOF
+	fake_bin pvs <<-EOF
+		#!/bin/sh
+		echo "  /dev/vda2"
+	EOF
+
+	echo "/dev/mapper/vg0-root / ext4 rw,noatime 0 0" > proc/mounts
+	for provider in $PROVIDERS; do
+		CLOUD="$provider" atf_check \
+			-o match:"sfdisk .*/dev/vda" \
+			-o match:"partx .*/dev/vda" \
+			-o match:"pvresize /dev/vda2" \
+			-o match:"lvextend -l \\+85%VG /dev/mapper/vg0-root" \
+			-o match:"resize2fs /dev/mapper/vg0-root" \
+			sh -c ". $lib; init__expand_root"
+	done
+}
+
+expand_root_lvm_whole_disk_body() {
+	# Test LVM on whole disk (e.g., /dev/sdb -> PV -> VG -> LV, no partition)
+	mkdir -p proc sys/class/block \
+		sys/devices/pci0000:00/0000:00:05.0/virtio3/block/vdb/device \
+		dev/mapper
+	ln -s ../../devices/pci0000:00/0000:00:05.0/virtio3/block/vdb sys/class/block/vdb
+
+	# Create fake LVM device
+	mkdir -p sys/class/block/dm-1
+	ln -s /dev/mapper/vg1-root dev/mapper/vg1-root
+
+	# Mock LVM commands - PV is on whole disk (no partition)
+	fake_bin lvs <<-EOF
+		#!/bin/sh
+		echo "  vg1"
+	EOF
+	fake_bin pvs <<-EOF
+		#!/bin/sh
+		echo "  /dev/vdb"
+	EOF
+
+	echo "/dev/mapper/vg1-root / ext4 rw,noatime 0 0" > proc/mounts
+	for provider in $PROVIDERS; do
+		CLOUD="$provider" atf_check \
+			-o match:"pvresize /dev/vdb" \
+			-o match:"lvextend -l \\+85%VG /dev/mapper/vg1-root" \
+			-o match:"resize2fs /dev/mapper/vg1-root" \
+			-o not-match:"sfdisk" \
+			-o not-match:"partx" \
+			sh -c ". $lib; init__expand_root"
+	done
+}
+
 ethernets_body() {
 	fake_interfaces lo br0 eth0 eth2 eth11