initramfs-framework: unmount automounts before switch_root

If mounts are left lingering, then after we switch_root, attempts to
modify the block devices will result in an EBUSY with no way to unmount
them.  As we're about to switch_root anyways, there isn't much use to
keep anything mounted unless it has the new rootfs.

(From OE-Core rev: 999883990235251127b65f2277dcb40004e7f657)

Signed-off-by: Justin Bronder <jsbronder@cold-front.org>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 4dc7af6d25597ea10ea43e76c7c3d7251462c0e5)
Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>
(cherry picked from commit 991631492f4fafc1852113a34a60b025342518b6)
Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 12 insertions, 0 deletions

diff --git a/meta/recipes-core/initrdscripts/initramfs-framework/finish b/meta/recipes-core/initrdscripts/initramfs-framework/finish
index 717383ebac..f08a920867 100755
--- a/meta/recipes-core/initrdscripts/initramfs-framework/finish
+++ b/meta/recipes-core/initrdscripts/initramfs-framework/finish
@@ -12,6 +12,18 @@ finish_run() {
                         fatal "ERROR: There's no '/dev' on rootfs."
                 fi
 
+                # Unmount anything that was automounted by busybox via mdev-mount.sh.
+                # We're about to switch_root, and leaving anything mounted will prevent
+                # the next rootfs from modifying the block device.  Ignore ROOT_DISK,
+                # if it was set by setup-live, because it'll be mounted over loopback
+                # to ROOTFS_DIR.
+                local dev
+                for dev in /run/media/*; do
+                        if mountpoint -q "${dev}" && [ "${dev##*/}" != "${ROOT_DISK}" ]; then
+                                umount -f "${dev}" || debug "Failed to unmount ${dev}"
+                        fi
+                done
+
                 info "Switching root to '$ROOTFS_DIR'..."
 
                 debug "Moving /dev, /proc and /sys onto rootfs..."