Btrfs: start of block group code

Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 078cb9c..8a2545f 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -125,6 +125,7 @@
 		btrfs_set_super_device_root(fs_info->disk_super,
 					    bh_blocknr(dev_root->node));
 	}
+	btrfs_write_dirty_block_groups(trans, extent_root);
 	while(1) {
 		old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
 		if (old_extent_block == bh_blocknr(extent_root->node))
@@ -135,6 +136,7 @@
 					&extent_root->root_key,
 					&extent_root->root_item);
 		BUG_ON(ret);
+		btrfs_write_dirty_block_groups(trans, extent_root);
 	}
 	return 0;
 }