@@ -350,11 +350,13 @@ struct btrfs_super_block {
* ones specified below then we will fail to mount
*/
#define BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF (1ULL << 0)
+#define BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL (2ULL << 0)
#define BTRFS_FEATURE_COMPAT_SUPP 0ULL
#define BTRFS_FEATURE_COMPAT_RO_SUPP 0ULL
#define BTRFS_FEATURE_INCOMPAT_SUPP \
- BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF
+ (BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF | \
+ BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL)
/*
* A leaf is full of items. offset and size tell us where to find