Btrfs: extent fixes

Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index b737925..78407d3 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -57,6 +57,11 @@
 	u64 snapuuid[2]; /* root specific uuid */
 } __attribute__ ((__packed__));
 
+struct ctree_super_block {
+	struct ctree_root_info root_info;
+	struct ctree_root_info extent_info;
+} __attribute__ ((__packed__));
+
 struct item {
 	struct key key;
 	u16 offset;