fs-resize: gate resize2fs on fsck, fix sd* boot partition name, explain warnings

Analysis of a first-boot resize log (docs/resize.log):

- The two FAT warnings it records are expected and harmless. The 256MB
  boot partition ships the same out-of-spec FAT32 (16375 clusters, below
  the 65525 minimum) as ROCKNIX and the rest of the RK3326 ecosystem;
  vendor U-Boots are only tested against that layout, so reformatting it
  is exactly the change that has caused boot loops before. The
  boot-sector/backup difference is the kernel vfat dirty flag, written
  to the primary sector only while /flash is mounted read-write; the
  shipped image was verified to carry identical primary and backup
  sectors. The script now appends a NOTE to the log so the warnings stop
  being reported as failures.

Real defects fixed:

- resize2fs ran regardless of the e2fsck result; on unfixed corruption
  (exit above 2) growing the filesystem would compound the damage. The
  resize is now skipped in that case, leaving the grown partition for a
  later retry after a manual fsck.
- The boot-partition path was hardcoded as ${DISK}p1, which is wrong for
  /dev/sdX disks (sdXp1 does not exist), so the FAT serial
  randomization silently never ran there. Derive the partition name per
  device type alongside DISK.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

projects/ArchR/packages/sysutils/busybox/scripts/fs-resize

@@ -39,9 +39,14 @@ if [ -e /storage/.please_resize_me ] ; then
   case $PART in
     "/dev/mmcblk"*|"/dev/nvme"*)
       DISK=$(echo $PART | sed s/p[0-9]$//g)
+      PART1="${DISK}p1"
       ;;
     *)
       DISK=$(echo $PART | sed s/[0-9]$//g)
+      # /dev/sdX partitions have no "p" separator; ${DISK}p1 pointed at a
+      # nonexistent node and the boot-partition serial was never randomized
+      # on those devices.
+      PART1="${DISK}1"
       ;;
   esac
 
@@ -60,9 +65,26 @@ if [ -e /storage/.please_resize_me ] ; then
     echo ""
 
     StartProgressLog spinner "Resizing partition...   " "parted -s -f -m $DISK resizepart $PARTNUM 100% >>$LOG 2>&1"
-    StartProgressLog spinner "Checking file system... " "e2fsck -f -p $PART >>$LOG 2>&1"
-    StartProgressLog spinner "Resizing file system... " "resize2fs $PART >>$LOG 2>&1"
-    StartProgressLog spinner "Regenerating UUIDs...   " "tune2fs $PART -U random >>$LOG 2>&1; fatlabel -i -r ${DISK}p1 >>$LOG 2>&1"
+    # e2fsck -p exits 0 (clean), 1 (fixed) or 2 (fixed, reboot wanted);
+    # anything above means unfixed corruption, and growing a broken
+    # filesystem with resize2fs would compound the damage. Leave the
+    # partition grown but the filesystem untouched; a later boot can
+    # retry after a manual fsck.
+    StartProgressLog spinner "Checking file system... " "e2fsck -f -p $PART >>$LOG 2>&1; echo \$? >/tmp/fsck-status"
+    FSCK_STATUS=$(cat /tmp/fsck-status 2>/dev/null || echo 0)
+    if [ "${FSCK_STATUS:-0}" -le 2 ]; then
+      StartProgressLog spinner "Resizing file system... " "resize2fs $PART >>$LOG 2>&1"
+    else
+      echo "e2fsck exited ${FSCK_STATUS}; skipping resize2fs to avoid growing a corrupted filesystem" | tee -a $LOG
+    fi
+    StartProgressLog spinner "Regenerating UUIDs...   " "tune2fs $PART -U random >>$LOG 2>&1; fatlabel -i -r $PART1 >>$LOG 2>&1"
+    # The two FAT warnings fatlabel prints here are expected and harmless:
+    # the 256MB boot partition ships the same out-of-spec FAT32 layout as
+    # the whole RK3326 ecosystem (vendor U-Boots are only tested against
+    # it, so it must not be "fixed"), and the boot-sector/backup difference
+    # is the kernel vfat dirty flag, written to the primary sector only
+    # while /flash is mounted read-write.
+    echo "NOTE: the FAT32 cluster-count and boot-sector-backup warnings above are expected and harmless." >>$LOG
     StartProgressLog spinner "Syncing to disk...      " "sync >>$LOG 2>&1"
     StartProgress countdown "Rebooting in 5s...     " 5 "NOW"
   else