diff --git a/common/flatpak-run.c b/common/flatpak-run.c
index 8aa6a863..b35d1df7 100644
--- a/common/flatpak-run.c
+++ b/common/flatpak-run.c
@@ -1717,6 +1717,14 @@ flatpak_run_add_extension_args (GPtrArray    *argv_array,
       g_autofree char *ref = g_build_filename (full_directory, ".ref", NULL);
       g_autofree char *real_ref = g_build_filename (ext->files_path, ext->directory, ".ref", NULL);
 
+      if (ext->needs_tmpfs)
+        {
+          g_autofree char *parent = g_path_get_dirname (full_directory);
+          add_args (argv_array,
+                    "--tmpfs", parent,
+                    NULL);
+        }
+
       add_args (argv_array,
                 "--bind", ext->files_path, full_directory,
                 NULL);
diff --git a/common/flatpak-utils.c b/common/flatpak-utils.c
index d270e39a..1ccedcd7 100644
--- a/common/flatpak-utils.c
+++ b/common/flatpak-utils.c
@@ -2491,6 +2491,7 @@ flatpak_list_extensions (GKeyFile   *metakey,
               g_autofree char *prefix = g_strconcat (extension, ".", NULL);
               g_auto(GStrv) refs = NULL;
               int j;
+              gboolean needs_tmpfs = TRUE;
 
               refs = flatpak_list_deployed_refs ("runtime", prefix, arch, branch,
                                                  NULL, NULL);
@@ -2503,6 +2504,8 @@ flatpak_list_extensions (GKeyFile   *metakey,
                   if (subdir_files)
                     {
                       ext = flatpak_extension_new (extension, refs[j], dir_ref, extended_dir, subdir_files);
+                      ext->needs_tmpfs = needs_tmpfs;
+                      needs_tmpfs = FALSE; /* Only first subdir needs a tmpfs */
                       res = g_list_prepend (res, ext);
                     }
                 }
@@ -2510,7 +2513,7 @@ flatpak_list_extensions (GKeyFile   *metakey,
         }
     }
 
-  return res;
+  return g_list_reverse (res);
 }
 
 
diff --git a/common/flatpak-utils.h b/common/flatpak-utils.h
index 27e7666a..7b124ebd 100644
--- a/common/flatpak-utils.h
+++ b/common/flatpak-utils.h
@@ -232,6 +232,7 @@ typedef struct
   char *ref;
   char *directory;
   char *files_path;
+  gboolean needs_tmpfs;
 } FlatpakExtension;
 
 void flatpak_extension_free (FlatpakExtension *extension);
diff --git a/tests/test-extensions.sh b/tests/test-extensions.sh
index 90b2a84d..16272854 100755
--- a/tests/test-extensions.sh
+++ b/tests/test-extensions.sh
@@ -53,9 +53,7 @@ add_extensions () {
     mkdir -p $DIR/files/foo/ext4
     mkdir -p $DIR/files/foo/none
     mkdir -p $DIR/files/foo/dir
-    mkdir -p $DIR/files/foo/dir/foo
     mkdir -p $DIR/files/foo/dir2
-    mkdir -p $DIR/files/foo/dir2/foo
 
     cat >> $DIR/metadata <<EOF
 [Extension org.test.Extension1]
@@ -109,6 +107,7 @@ make_extension org.test.Extension3 master
 make_extension org.test.Extension3 not-master
 make_extension org.test.Extension4 master
 make_extension org.test.Dir.foo master
+make_extension org.test.Dir.bar master
 
 assert_has_extension_file () {
     local prefix=$1
@@ -134,6 +133,7 @@ assert_has_extension_file /usr ext3/extension-org.test.Extension3:not-master
 assert_not_has_extension_file /usr ext4/exists
 assert_has_extension_file /usr dir/foo/exists
 assert_has_extension_file /usr dir/foo/extension-org.test.Dir.foo:master
+assert_has_extension_file /usr dir/bar/extension-org.test.Dir.bar:master
 assert_not_has_extension_file /usr dir2/foo/exists
 
 echo "ok runtime extensions"
@@ -155,6 +155,7 @@ assert_has_extension_file /app ext3/extension-org.test.Extension3:not-master
 assert_not_has_extension_file /app ext4/exists
 assert_has_extension_file /app dir/foo/exists
 assert_has_extension_file /app dir/foo/extension-org.test.Dir.foo:master
+assert_has_extension_file /app dir/bar/extension-org.test.Dir.bar:master
 assert_not_has_extension_file /app dir2/foo/exists
 
 echo "ok app extensions"