v4.19.13 snapshot.
diff --git a/fs/btrfs/export.h b/fs/btrfs/export.h
new file mode 100644
index 0000000..57488ec
--- /dev/null
+++ b/fs/btrfs/export.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef BTRFS_EXPORT_H
+#define BTRFS_EXPORT_H
+
+#include <linux/exportfs.h>
+
+extern const struct export_operations btrfs_export_ops;
+
+struct btrfs_fid {
+ u64 objectid;
+ u64 root_objectid;
+ u32 gen;
+
+ u64 parent_objectid;
+ u32 parent_gen;
+
+ u64 parent_root_objectid;
+} __attribute__ ((packed));
+
+#endif