installer: fix the "umount: XXX not mounted" error message during postinst

chromeos-setimage

 #!/bin/sh -u
 # Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 #
 # A script to display or change the preferred image
 
 # Load functions and constants for chromeos-install.
 . "$(dirname "$0")/chromeos-common.sh" || exit 1
 if [ -e /usr/lib/shflags ]; then
@@ skipping 97 matching lines @@
 fi
 
 # Setup loop devices so that we don't get burned by the kernel not knowing
 # about updated partition changes.
 ESP_LOOP=
 ROOT_LOOP=
 KERN_LOOP=
 
 cleanup_loop() {
   local dev="$1"
+  local cleanup_command="$2"
   if [ -z "$dev" ]; then
     return 0
   fi
-  (sudo umount "$dev" || true)
+  if [ -n "$cleanup_command" ]; then
+    (sudo "$cleanup_command" "$dev" || true)
+  fi
   (sudo losetup -d "$dev" || true)
 }
 
 cleanup() {
-  cleanup_loop "${ESP_LOOP}"
+  # Currently only ESP may be mounted. KERN and ROOT are never mounted.
+  cleanup_loop "${ESP_LOOP}" "umount"
   ESP_LOOP=
-  cleanup_loop "${KERN_LOOP}"
+  cleanup_loop "${KERN_LOOP}" ""

[Will Drewry, 2010/11/18 09:20:15]

Do you need to specify empty $2s here?

[Hung-Te, 2010/11/18 09:49:02]

Although it may be not necessary, I think an explicit "" may help letting
developer to know "you have to pass something here"

   KERN_LOOP=
-  cleanup_loop "${ROOT_LOOP}"
+  cleanup_loop "${ROOT_LOOP}" ""
   ROOT_LOOP=
 
   # Failing to clean this up isn't the worst.
   if [ -n "${ESP_TMP_DIR}" ]; then
     rmdir "${ESP_TMP_DIR}" || true
   fi
 
   rm -f ${tempfile} || true
 }
 
@@ skipping 211 matching lines @@
 grep -qs '^set default=3' ${mountpoint}/efi/boot/grub.cfg && echo "B (verified)"
 
 echo "Current legacy boot default is:"
 # Print the [new] default choice
 grep -qs 's-hd\.A$' ${mountpoint}/syslinux/default.cfg && echo "A"
 grep -qs 's-hd\.B$' ${mountpoint}/syslinux/default.cfg && echo "B"
 grep -qs 'vhd\.A$' ${mountpoint}/syslinux/default.cfg && echo "A (verified)"
 grep -qs 'vhd\.B$' ${mountpoint}/syslinux/default.cfg && echo "B (verified)"
 
 exit $EXIT_CODE