1 files changed, 6 insertions, 0 deletions
diff --git a/ctree.h b/ctree.h
index b9fb732c..89e47abd 100644
--- a/ctree.h
+++ b/ctree.h
@@ -40,6 +40,12 @@ struct btrfs_trans_handle;
 struct btrfs_free_space_ctl;
 #define BTRFS_MAGIC 0x4D5F53665248425FULL /* ascii _BHRfS_M, no null */
 
+/*
+ * Fake signature for an unfinalized filesystem, structures might be partially
+ * created or missing.
+ */
+#define BTRFS_MAGIC_PARTIAL 0x4D5F536652484221ULL /* ascii !BHRfS_M, no null */
+
 #define BTRFS_MAX_MIRRORS 3
 
 #define BTRFS_MAX_LEVEL 8