Shrink data partition for leaner disk images and faster flashing (#4764)

Borrow shrinking used in home-assistant/operating-system-full-images for
reducing the data partition size to only fit its contents. Currently the
data partition is intentionally overprovisioned to comfortably fit all
docker images in the hassio build. This results in unnecessarily large
image which takes longer to flash, as all the zeroes at the end of the
filesystem need to be written to the SD card.

For OVA and aarch64 VM formats, the image is resized before creating the
VM images - this also makes all generic-aarch64 images sized to 32GB,
unlike 6GB which inherently needed resizing before use. Some juggling
extra juggling is needed in the aarch64 post-image step, as we want to
preserve the raw image (e.g. for generic aarch64 boards) but it's
desirable to keep it minimal as well, as it's meant to be flashed to
real hardware storage.

buildroot-external/board/arm-uefi/generic-aarch64/haos-hook.sh

@@ -19,6 +19,14 @@ function haos_pre_image() {
 
 
 function haos_post_image() {
+    local hdd_img="$(haos_image_name img)"
+    local hdd_img_orig="$(haos_image_name img.orig)"
+
+    # Resize for VM images, preserving original
+    cp "$hdd_img" "$hdd_img_orig"
+    resize_disk_image_virtual 32G
+
+    # Create VM archives
     convert_disk_image_virtual vmdk
     convert_disk_image_virtual vdi
     convert_disk_image_virtual qcow2
@@ -27,5 +35,7 @@ function haos_post_image() {
     convert_disk_image_zip vdi
     convert_disk_image_xz qcow2
 
+    # Use unresized image for .img.xz
+    mv "$hdd_img_orig" "$hdd_img"
     convert_disk_image_xz
 }

buildroot-external/board/arm-uefi/generic-aarch64/meta

@@ -6,6 +6,5 @@ KERNEL_FILE=Image
 PARTITION_TABLE_TYPE=gpt
 BOOT_SIZE=32M
 BOOT_SPL=false
-DISK_SIZE=6G
 SUPERVISOR_MACHINE=qemuarm-64
 SUPERVISOR_ARCH=aarch64

buildroot-external/board/pc/generic-x86-64/meta

@@ -6,6 +6,5 @@ KERNEL_FILE=bzImage
 PARTITION_TABLE_TYPE=gpt
 BOOT_SIZE=32M
 BOOT_SPL=false
-DISK_SIZE=6G
 SUPERVISOR_MACHINE=generic-x86-64
 SUPERVISOR_ARCH=amd64

buildroot-external/board/pc/ova/haos-hook.sh

@@ -22,6 +22,8 @@ function haos_post_image() {
     local hdd_img="$(haos_image_name img)"
 
     # Virtual Disk images
+    resize_disk_image_virtual 32G
+
     convert_disk_image_virtual vmdk
     convert_disk_image_virtual vhdx
     convert_disk_image_virtual vdi

buildroot-external/board/pc/ova/meta

@@ -6,6 +6,5 @@ KERNEL_FILE=bzImage
 PARTITION_TABLE_TYPE=gpt
 BOOT_SIZE=32M
 BOOT_SPL=false
-DISK_SIZE=32G
 SUPERVISOR_MACHINE=qemux86-64
 SUPERVISOR_ARCH=amd64

buildroot-external/genimage/genimage.cfg

@@ -1,8 +1,6 @@
 include("images-os.cfg")
 
 image "${IMAGE_NAME}.img" {
-	size = "${DISK_SIZE:-2G}"
-
 	include("hdimage-${PARTITION_TABLE_TYPE}.cfg")
 
 	include("partition-spl-${BOOT_SPL_TYPE}.cfg")

buildroot-external/genimage/partitions-os-gpt.cfg

@@ -42,6 +42,5 @@ partition hassos-overlay {
 partition hassos-data {
 	partition-type-uuid = "linux"
 	partition-uuid = "a52a4597-fa3a-4851-aefd-2fbe9f849079"
-	size = ${DATA_SIZE}
 	image = ${DATA_IMAGE}
 }

buildroot-external/genimage/partitions-os-mbr.cfg

@@ -41,7 +41,6 @@ partition hassos-overlay {
 
 partition hassos-data {
 	partition-type = 0x83
-	size = ${DATA_SIZE}
 	image = ${DATA_IMAGE}
 	forced-primary = "yes"
 }

buildroot-external/package/hassio/create-data-partition.sh

@@ -42,3 +42,17 @@ curl -fsL -o "${data_dir}/supervisor/apparmor/hassio-supervisor" "${APPARMOR_URL
 # Persist build-time updater channel
 jq -n --arg channel "${channel}" '{"channel": \$channel}' > "${data_dir}/supervisor/updater.json"
 EOF
+
+# Tear down docker and unmount the data partition before shrinking
+docker rm -f "${container}" > /dev/null
+sudo umount "${data_dir}"
+trap - ERR EXIT
+
+# Shrink the filesystem to its minimum size
+e2fsck -f -y "${data_img}"
+resize2fs -M "${data_img}"
+
+# Truncate image file to match the filesystem size
+block_count=$(dumpe2fs -h "${data_img}" 2>/dev/null | awk '/^Block count:/{print $3}')
+block_size=$(dumpe2fs -h "${data_img}" 2>/dev/null | awk '/^Block size:/{print $3}')
+truncate --size="$((block_count * block_size))" "${data_img}"

buildroot-external/scripts/hdd-image.sh

@@ -4,7 +4,6 @@ BOOTSTATE_SIZE=8M
 SYSTEM_SIZE=256M
 KERNEL_SIZE=24M
 OVERLAY_SIZE=96M
-DATA_SIZE=1280M
 
 function create_disk_image() {
     if [ -f "${BOARD_DIR}/genimage.cfg" ]; then
@@ -24,7 +23,7 @@ function create_disk_image() {
     ota_version="$(haos_version)"
     export ota_compatible ota_version
     # variables used in genimage configs
-    export BOOTSTATE_SIZE SYSTEM_SIZE KERNEL_SIZE OVERLAY_SIZE DATA_SIZE
+    export BOOTSTATE_SIZE SYSTEM_SIZE KERNEL_SIZE OVERLAY_SIZE
     RAUC_MANIFEST=$(tempio -template "${BR2_EXTERNAL_HAOS_PATH}/ota/manifest.raucm.gtpl")
     IMAGE_NAME="$(haos_image_basename)"
     BOOT_SPL_TYPE=$(test "$BOOT_SPL" == "true" && echo "spl" || echo "nospl")
@@ -52,6 +51,14 @@ function create_disk_image() {
       --includepath "${BOARD_DIR}:${BR2_EXTERNAL_HAOS_PATH}/genimage"
 }
 
+function resize_disk_image_virtual() {
+    local size="${1}"
+    local hdd_img
+    hdd_img="$(haos_image_name img)"
+
+    qemu-img resize -q -f raw "${hdd_img}" "${size}"
+}
+
 function convert_disk_image_virtual() {
     local hdd_ext="${1}"
     local hdd_img