[PATCH openbmc 7/7] obmc-initfs: shutdown when rofs is a loop mounted image in /run

[OpenBMC Patches <openbmc-patches@stwcx.xyz>]

From: Milton Miller <miltonm@us.ibm.com>

If one sets rodir=/run/image-rofs roopts=ro,loop and transfers
an image one can run from a base image in ram.  However, the
shutdown will fail to unmount /run because it is busy and then
fails to unmount /cow which causes oldroot to be still mounted.

By moving the mount to the side everything cleans up (as long
as there are no other mounts under run, and systemd-shutdown
tried to do as much as possible).

Signed-off-by: Milton Miller <miltonm@us.ibm.com>
---
 .../recipes-phosphor/obmc-phosphor-initfs/files/obmc-shutdown.sh | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/meta-phosphor/common/recipes-phosphor/obmc-phosphor-initfs/files/obmc-shutdown.sh b/meta-phosphor/common/recipes-phosphor/obmc-phosphor-initfs/files/obmc-shutdown.sh
index 7d1157a..3eff1ea 100644
--- a/meta-phosphor/common/recipes-phosphor/obmc-phosphor-initfs/files/obmc-shutdown.sh
+++ b/meta-phosphor/common/recipes-phosphor/obmc-phosphor-initfs/files/obmc-shutdown.sh
@@ -15,11 +15,16 @@ else
 	umount_proc=
 fi
 
-# remove an empty oldroot, that means we are not invoked from systemd-shutdown
+# Remove an empty oldroot, that means we are not invoked from systemd-shutdown
 rmdir /oldroot 2>/dev/null
 
+# Move /oldroot/run to /mnt in case it has the underlying rofs loop mounted.
+# Ordered before /oldroot the overlay is unmounted before the loop mount
+mkdir -p /mnt
+mount --move /oldroot/run /mnt
+
 set -x
-for f in $( awk '/oldroot/ { print $2 }' < /proc/mounts | sort -r )
+for f in $( awk '/oldroot|mnt/ { print $2 }' < /proc/mounts | sort -r )
 do
 	umount $f
 done
-- 
2.6.4