Btrfs: block group switching

Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 756ea9d..1bb6286 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -249,10 +249,13 @@
 /* tag for the radix tree of block groups in ram */
 #define BTRFS_BLOCK_GROUP_DIRTY 0
 #define BTRFS_BLOCK_GROUP_AVAIL 1
-#define BTRFS_BLOCK_GROUP_HINTS 8
 #define BTRFS_BLOCK_GROUP_SIZE (256 * 1024 * 1024)
+
+
+#define BTRFS_BLOCK_GROUP_DATA 1
 struct btrfs_block_group_item {
 	__le64 used;
+	u8 flags;
 } __attribute__ ((__packed__));
 
 struct btrfs_block_group_cache {