Refactor union mounting into its own function.

1 files changed, 50 insertions, 0 deletions

diff --git a/scripts/live-helpers b/scripts/live-helpers
index aacfe93..3ec1e7b 100644
--- a/scripts/live-helpers
+++ b/scripts/live-helpers
@@ -608,3 +608,53 @@ link_files ()
 		fi
 	done
 }
+
+do_union () {
+	root_backing="${1}"
+	unionrw="${2}"
+	unionro="${3}"
+	unionmountpoint="${4}"
+
+	if [ "${UNIONTYPE}" = "aufs" ]
+	then
+		rw_opt="rw"
+		ro_opt="rr+wh"
+		noxino_opt="noxino,"
+	elif [ "${UNIONTYPE}" = "unionfs-fuse" ]
+	then
+		rw_opt="RW"
+		ro_opt="RO"
+	else
+		rw_opt="rw"
+		ro_opt="ro"
+	fi
+
+	case "${UNIONTYPE}" in
+		unionfs-fuse)
+			# FIXME: handle PERSISTENT_READONLY
+			unionmountopts="-o cow -o noinitgroups -o default_permissions -o allow_other -o use_ino -o suid"
+			unionmountopts="${unionmountopts} ${unionrw}=${rw_opt}:${unionro}=${ro_opt}"
+			( sysctl -w fs.file-max=391524 ; ulimit -HSn 16384
+			unionfs-fuse ${unionmountopts} "${unionmountpoint}" ) && \
+			( mkdir -p /run/sendsigs.omit.d
+			pidof unionfs-fuse >> /run/sendsigs.omit.d/unionfs-fuse || true )
+			;;
+
+		overlayfs)
+			# FIXME: is PERSISTENT_READONLY possible? (overlayfs only handles two dirs, but perhaps they can be chained?)
+			unionmountopts="-o noatime,lowerdir=${unionro},upperdir=${unionrw}"
+			mount -t ${UNIONTYPE} ${unionmountopts} ${UNIONTYPE} "${unionmountpoint}"
+			;;
+
+		*)
+			if [ -n "${PERSISTENT_READONLY}" ]
+			then
+				mount -t tmpfs -o rw,noatime,mode=755 tmpfs "${unionrw}"
+				unionmountopts="-o noatime,${noxino_opt}dirs=${unionrw}=${rw_opt}:${root_backing}=${ro_opt}:${unionro}=${ro_opt}"
+			else
+				unionmountopts="-o noatime,${noxino_opt}dirs=${unionrw}=${rw_opt}:${unionro}=${ro_opt}"
+			fi
+			mount -t ${UNIONTYPE} ${unionmountopts} ${UNIONTYPE} "${unionmountpoint}"
+			;;
+	esac
+}