Straw Man 1-prep/templates/iiab-expand-rootfs.service based on 2020's PR #2522 + /usr/sbin/iiab-expand-rootfs "bash -xe" exit-on-error (to defer deleting /.expand-rootfs)

roles/1-prep/templates/iiab-expand-rootfs

@@ -1,4 +1,4 @@
-#!/bin/bash -x
+#!/bin/bash -xe
 
 # Expand rootfs partition to its maximum size, if /.expand-rootfs exists.
 # Used by /etc/systemd/system/iiab-expand-rootfs.service on IIAB boot.
@@ -15,6 +15,8 @@ if [ -f /.expand-rootfs ] || [ -f /.resize-rootfs ]; then
         # 2022-02-17: Uses do_expand_rootfs() from:
         # https://github.com/RPi-Distro/raspi-config/blob/master/raspi-config
         raspi-config --expand-rootfs    # REQUIRES A REBOOT
+        rm -f /.expand-rootfs /.resize-rootfs
+        reboot                          # In future, we might warn interactive users that a reboot is coming?
     else                                # REQUIRES NO REBOOT; BEWARE iiab-expand-rootfs.service RACE CONDITION WITH fsck (PR #2522 & #3325)
         # 2022-03-15: Borrows from above raspi-config URL's do_expand_rootfs()
         ROOT_PART="$(findmnt / -o SOURCE -n)"    # e.g. /dev/sda2 or /dev/mmcblk0p2
@@ -30,8 +32,10 @@ if [ -f /.expand-rootfs ] || [ -f /.resize-rootfs ]; then
         fi
 
         # Expand partition
-        growpart $ROOT_DEV $ROOT_PART_NUM    # raspi-config instead uses fdisk
+        growpart $ROOT_DEV $ROOT_PART_NUM || true    # raspi-config instead uses fdisk.  WARNING: growpart RC 2 is more severe than RC 1, and should possibly be handled separately in future?
+        rc=$?    # Make Return Code visible, for 'bash -x'
         resize2fs $ROOT_PART
+        rc=$?    # Make RC visible (as above)
 
         # 2022-03-15: Legacy code below worked with Raspberry Pi microSD cards
         # but *not* with USB boot drives, internal spinning disks/SSD's, etc.
@@ -53,7 +57,7 @@ if [ -f /.expand-rootfs ] || [ -f /.resize-rootfs ]; then
         # # Resize partition
         # growpart /dev/$root_dev $root_part_no
         # resize2fs /dev/$root_part
+
+        rm -f /.expand-rootfs /.resize-rootfs
     fi
-
-    rm -f /.expand-rootfs /.resize-rootfs
 fi

roles/1-prep/templates/iiab-expand-rootfs.service

@@ -1,14 +1,24 @@
 [Unit]
 Description=Root Filesystem Auto-Expander
+DefaultDependencies=no
+# 2022-08-08: IIAB's 4 core OS's have 'After=systemd-fsck-root.service' WITHIN
+# systemd-remount-fs.service, allowing us to avoid #3325 race condition w/ fsck
+After=systemd-remount-fs.service
+# 2022-08-08: While dphys-swapfile.service doesn't exist on Ubuntu, Mint
+# and pure Debian, the following line may still serve a purpose on RasPiOS:
+Before=dphys-swapfile.service
 
 [Service]
 Environment=TERM=linux
 Type=oneshot
 ExecStart=/usr/sbin/iiab-expand-rootfs
+# 2022-08-08: By default, systemd dangerously kills rootfs expansion after just
+# 90s (1TB microSD cards take ~8 min to expand).  Let's remove the time limit:
+TimeoutSec=infinity
 # "Standard output type syslog is obsolete"
 # StandardError=syslog
 # WHEREAS StandardError=journal is the default, per https://www.freedesktop.org/software/systemd/man/systemd.exec.html#StandardOutput=
-RemainAfterExit=no
+RemainAfterExit=yes
 
 [Install]
-WantedBy=multi-user.target
+WantedBy=local-fs.target