From 1dea2f35249bdb1aed50ef6a580d52da754396e6 Mon Sep 17 00:00:00 2001
From: Chris Alfonso <calfonso@redhat.com>
Date: Thu, 15 Aug 2013 12:45:31 -0400
Subject: [PATCH] Call sync before unmounting keeps the mount from being busy.

here is a bug associated with this patch because there is a
workaround included. Calling sync to enable the unmounting...
https://bugs.launchpad.net/diskimage-builder/+bug/1214388

Change-Id: I9d5a1f092fd8f3ae1c14de03dd516203baab4da3
---
 lib/img-functions | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/lib/img-functions b/lib/img-functions
index 470f8ed6..23a19d19 100644
--- a/lib/img-functions
+++ b/lib/img-functions
@@ -14,6 +14,12 @@
 # under the License.
 
 function unmount_image () {
+    # Calling sync before helps ensure the mount isn't busy when you unmount it.
+    # Previously observing having disk corruption issues; one possibility is
+    # qemu-nbd not flushing dirty pages on disconnect?
+    # https://bugs.launchpad.net/diskimage-builder/+bug/1214388
+    sync
+
     # unmount from the chroot
     # Don't use TMP_MOUNT_PATH here, it might not have been set.
     local MOUNTS
@@ -21,12 +27,6 @@ function unmount_image () {
     for M in $MOUNTS; do
         sudo umount -f $M || true
     done
-    # give it a second (ok really 5) to umount XXX - why? should instead track
-    # the mount data / lsof etc.
-    sleep 5
-    # having disk corruption issues; one possibility is qemu-nbd not flushing
-    # dirty pages on disconnect?
-    sync
     if [ -n "$EXTRA_UNMOUNT" ]; then
         $EXTRA_UNMOUNT
     fi