[PATCH] meta: Explicitly undo wic mounts

[Uladzimir Bely <ubely@ilbers.de>]

Creating wic image requires some host paths be equal to buildchroot paths.

Thus, we have a situation, when ${STAGING_DIR} that is equal to ${TMPDIR}
needs to be bind-mounted under it subdirectory so that path to the image
rootfs under buildchroot was the same as path outside.

E.g. we have the following mountpoint during wic imaging:

${TMPDIR}/work/<distro-arch>/buildchroot-target/1.0-r0/rootfs/${TMPDIR}

In this situation, an issue was caught under some chroots, that final
event-based unmounting didsn't completely unmount everything. This was
reproduced, at least, under buster host and bullseye chroot.

This fix solved the problem by explicit unmounting wic-related mounts.

Signed-off-by: Uladzimir Bely <ubely@ilbers.de>
---
 meta/classes/imagetypes_wic.bbclass | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/meta/classes/imagetypes_wic.bbclass b/meta/classes/imagetypes_wic.bbclass
index 61a74d4a..ef8b3b5f 100644
--- a/meta/classes/imagetypes_wic.bbclass
+++ b/meta/classes/imagetypes_wic.bbclass
@@ -146,6 +146,7 @@ IMAGE_CMD_wic() {
     wic_do_mounts
     generate_wic_image
     check_for_wic_warnings
+    wic_undo_mounts
 }
 
 wic_do_mounts[vardepsexclude] += "BITBAKEDIR"
@@ -164,6 +165,20 @@ wic_do_mounts() {
 EOSUDO
 }
 
+wic_undo_mounts[vardepsexclude] += "BITBAKEDIR"
+wic_undo_mounts() {
+    sudo -s <<'EOSUDO'
+        ( flock 9
+        set -e
+        for dir in ${BITBAKEDIR} ${SCRIPTSDIR} ${STAGING_DIR} ${BBLAYERS}; do
+            if mountpoint ${BUILDCHROOT_DIR}/$dir >/dev/null 2>&1; then
+                umount ${BUILDCHROOT_DIR}/$dir
+            fi
+        done
+        ) 9>${MOUNT_LOCKFILE}
+EOSUDO
+}
+
 generate_wic_image[vardepsexclude] += "WKS_FULL_PATH BITBAKEDIR TOPDIR"
 generate_wic_image() {
     export FAKEROOTCMD=${FAKEROOTCMD}
-- 
2.20.1