live-build/ubuntu-cpc/functions: Add teardown_mountpoint to reverse setup_mountpoint

* live-build/ubuntu-cpc/functions: Add a function, teardown_mountpoint,
  to reverse the work done in setup_mountpoint.  Lack of this function
  has forced users of setup_mountpoint to implement this separately
  and the implementations have diverged. (LP: #1716992)
* live-build/ubuntu-cpc/functions: Remove umount_settle function.
  The was only used where teardown_mountpoint was lacking.

debian/changelog

@@ -1,3 +1,15 @@
+livecd-rootfs (2.441.6) UNRELEASED; urgency=medium
+
+  [ Robert C Jennings ]
+  * live-build/ubuntu-cpc/functions: Add a function, teardown_mountpoint,
+    to reverse the work done in setup_mountpoint.  Lack of this function
+    has forced users of setup_mountpoint to implement this separately
+    and the implementations have diverged. (LP: #1716992)
+  * live-build/ubuntu-cpc/functions: Remove umount_settle function.
+    The was only used where teardown_mountpoint was lacking.
+
+ -- Robert C Jennings <robert.jennings@canonical.com>  Wed, 13 Sep 2017 13:36:40 -0500
+
 livecd-rootfs (2.441.5) zesty; urgency=medium
 
   [ Colin Watson ]

live-build/functions

@@ -91,6 +91,19 @@ setup_mountpoint() {
 
 }
 
+teardown_mountpoint() {
+    # Reverse the operations from setup_mountpoint
+    local mountpoint="$1"
+
+    umount "$mountpoint/tmp"
+    umount "$mountpoint/sys"
+    umount "$mountpoint/proc"
+    umount -R "$mountpoint/dev"
+    udevadm settle
+    sleep 3
+    mv resolv.conf.tmp "$mountpoint/etc/resolv.conf"
+}
+
 mount_partition() {
     partition="$1"
     mountpoint="$2"
@@ -134,16 +147,9 @@ EOF
 
 }
 
-umount_settle() {
-    # Unmount device, and let it settle
-    umount $1
-    udevadm settle
-}
-
 umount_partition() {
     local mountpoint=${1}
-    mv resolv.conf.tmp "$mountpoint/etc/resolv.conf"
+    teardown_mountpoint $mountpoint
-    umount -R $mountpoint
     udevadm settle
 
     if [ -n "${rootfs_dev_mapper}" -a -b "${rootfs_dev_mapper}" ]; then

live-build/ubuntu-cpc/hooks/032-root-squashfs.binary

@@ -36,11 +36,7 @@ chroot binary/boot/squashfs.dir mkdir /lib/modules
 chroot binary/boot/squashfs.dir rm /usr/sbin/grub-probe
 chroot binary/boot/squashfs.dir dpkg-divert --remove --local --rename /usr/sbin/grub-probe
 
-mv resolv.conf.tmp "binary/boot/squashfs.dir/etc/resolv.conf"
+teardown_mountpoint binary/boot/squashfs.dir
-umount "binary/boot/squashfs.dir/proc"
-umount "binary/boot/squashfs.dir/sys"
-umount -R "binary/boot/squashfs.dir/dev"
-umount "binary/boot/squashfs.dir/tmp"
 
 apt-get -qqy install squashfs-tools