Use bind mounts instead of symlinks to move directories to data volume

This makes the relocation more transparent to apps and users because
symlinks are sometimes treated differently.

Signed-off-by: Jan Dubois <[email protected]>

Author: jandubois

pkg/cidata/cidata.TEMPLATE.d/boot/05-persistent-data-volume.sh

@@ -44,8 +44,8 @@ if [ "$(awk '$2 == "/" {print $3}' /proc/mounts)" == "tmpfs" ]; then
 	fi
 	for DIR in ${DATADIRS}; do
 		if [ -d /mnt/data"${DIR}" ]; then
-			[ -e "${DIR}" ] && rm -rf "${DIR}"
-			ln -s /mnt/data"${DIR}" "${DIR}"
+			mkdir -p "${DIR}"
+			mount --bind /mnt/data"${DIR}" "${DIR}"
 		fi
 	done
 fi