[PATCH v4 1/1] expand-on-first-boot: Switch from resize2fs to systemd-growfs

[Tobias Schmidl <tobiasschmidl@siemens.com>]

We want to be more versatile in our approach of resizing the last
partition. Therefore we switch from resize2fs to systemd-growfs.

This allows for ext4, btrfs, xfs, and dm-crypt partitions to be resized.

Since systemd-growfs landed in v236, this obsoletes expand-on-first-boot
on stretch (v232).

Signed-off-by: Tobias Schmidl <tobiasschmidl@siemens.com>
---
 ...oot_1.1.bb => expand-on-first-boot_1.2.bb} |  5 +++--
 .../files/expand-last-partition.sh            | 21 +++++++++++++++++--
 2 files changed, 22 insertions(+), 4 deletions(-)
 rename meta/recipes-support/expand-on-first-boot/{expand-on-first-boot_1.1.bb => expand-on-first-boot_1.2.bb} (78%)

diff --git a/meta/recipes-support/expand-on-first-boot/expand-on-first-boot_1.1.bb b/meta/recipes-support/expand-on-first-boot/expand-on-first-boot_1.2.bb
similarity index 78%
rename from meta/recipes-support/expand-on-first-boot/expand-on-first-boot_1.1.bb
rename to meta/recipes-support/expand-on-first-boot/expand-on-first-boot_1.2.bb
index 1703a64..48d30d3 100644
--- a/meta/recipes-support/expand-on-first-boot/expand-on-first-boot_1.1.bb
+++ b/meta/recipes-support/expand-on-first-boot/expand-on-first-boot_1.2.bb
@@ -1,15 +1,16 @@
 # Resize last partition to full medium size on fist boot
 #
 # This software is a part of ISAR.
-# Copyright (c) Siemens AG, 2018
+# Copyright (c) Siemens AG, 2018-2022
 #
 # SPDX-License-Identifier: MIT
 
 inherit dpkg-raw
 
 DESCRIPTION = "This service grows the last partition to the full medium during first boot"
+MAINTAINER = "isar-users <isar-users@googlegroups.com>"
 
-DEBIAN_DEPENDS = "systemd, sed, grep, coreutils, mount, e2fsprogs, fdisk, util-linux"
+DEBIAN_DEPENDS = "systemd (>=236), sed, grep, coreutils, mount, fdisk, util-linux"
 
 SRC_URI = " \
     file://expand-on-first-boot.service \
diff --git a/meta/recipes-support/expand-on-first-boot/files/expand-last-partition.sh b/meta/recipes-support/expand-on-first-boot/files/expand-last-partition.sh
index c0edde7..1743890 100755
--- a/meta/recipes-support/expand-on-first-boot/files/expand-last-partition.sh
+++ b/meta/recipes-support/expand-on-first-boot/files/expand-last-partition.sh
@@ -3,7 +3,7 @@
 # Resize last partition to full medium size
 #
 # This software is a part of ISAR.
-# Copyright (c) Siemens AG, 2018
+# Copyright (c) Siemens AG, 2018-2022
 #
 # SPDX-License-Identifier: MIT
 
@@ -45,4 +45,21 @@ partx -u "${LAST_PART}"
 # when using systemd mount units.
 export EXT2FS_NO_MTAB_OK=1
 
-resize2fs "${LAST_PART}"
+if grep -q x-systemd.growfs /etc/fstab; then
+	echo "Found x-systemd.growfs option in /etc/fstab, won't call it explicitly." >&2
+	exit 0
+fi
+
+MOUNT_POINT=$(findmnt -o target -n "${LAST_PART}")
+UNMOUNT_AFTERWORDS=0
+if [ -z "${MOUNT_POINT}" ]; then
+	MOUNT_POINT=$(findmnt -o target -n --fstab "{$LAST_PART}")
+	if [ -z "${MOUNT_POINT}" ]; then
+		echo "Cannot find mount point for ${LAST_PART}" >&2
+		exit 1
+	else
+		UNMOUNT_AFTERWORDS=1
+	fi
+fi
+/lib/systemd/systemd-growfs "${MOUNT_POINT}"
+[ $UNMOUNT_AFTERWORDS -eq 1 ] && umount "${MOUNT_POINT}"
-- 
2.36.1