diff --git a/ctree.h b/ctree.h
index 10dc8388..7c1bef55 100644
--- a/ctree.h
+++ b/ctree.h
@@ -310,6 +310,7 @@ static inline unsigned long btrfs_chunk_item_size(int num_stripes)
 #define BTRFS_SUPER_FLAG_SEEDING		(1ULL << 32)
 #define BTRFS_SUPER_FLAG_METADUMP		(1ULL << 33)
 #define BTRFS_SUPER_FLAG_METADUMP_V2		(1ULL << 34)
+#define BTRFS_SUPER_FLAG_CHANGING_FSID		(1ULL << 35)
 
 #define BTRFS_BACKREF_REV_MAX		256
 #define BTRFS_BACKREF_REV_SHIFT		56