diff --git a/lib/tiny-cloud/init b/lib/tiny-cloud/init
index cf51e98..ee3fdbc 100644
--- a/lib/tiny-cloud/init
+++ b/lib/tiny-cloud/init
@@ -31,8 +31,15 @@ INIT_ACTIONS_FINAL="
 
 init__expand_root() {
     local dev=$(awk '$2 == "/" {print $1}' "$ROOT"/proc/mounts)
+    local filesystem=$(awk '$2 == "/" {print $3}' "$ROOT"/proc/mounts)
     local partition=$(cat "$ROOT/sys/class/block/${dev#/dev/}/partition" 2>/dev/null)
 
+    # only support ext2/ext3/ext4 for now
+    case "$filesystem" in
+        ext*) ;;
+        *) return;;
+    esac
+
     if [ -n "$partition" ]; then
         # it's a partition, resize it
         local volume=$(readlink -f "$ROOT/sys/class/block/${dev#/dev/}/..")