diff --git a/ctree.h b/ctree.h
index 5242595f..75675ef3 100644
--- a/ctree.h
+++ b/ctree.h
@@ -2523,8 +2523,7 @@ int btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
 			    u64 orig_parent, u64 parent,
 			    u64 root_objectid, u64 ref_generation,
 			    u64 owner_objectid);
-int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
-				    struct btrfs_root *root);
+int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans);
 int btrfs_free_block_groups(struct btrfs_fs_info *info);
 int btrfs_read_block_groups(struct btrfs_root *root);
 struct btrfs_block_group_cache *
diff --git a/extent-tree.c b/extent-tree.c
index 2958fee2..8b36a36c 100644
--- a/extent-tree.c
+++ b/extent-tree.c
@@ -1727,8 +1727,7 @@ fail:
 
 }
 
-int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
-				   struct btrfs_root *root)
+int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans)
 {
 	struct extent_io_tree *block_group_cache;
 	struct btrfs_block_group_cache *cache;
@@ -1739,7 +1738,7 @@ int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
 	u64 end;
 	u64 ptr;
 
-	block_group_cache = &root->fs_info->block_group_cache;
+	block_group_cache = &trans->fs_info->block_group_cache;
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
diff --git a/transaction.c b/transaction.c
index 1e2a7b96..20a78c73 100644
--- a/transaction.c
+++ b/transaction.c
@@ -61,7 +61,7 @@ static int update_cowonly_root(struct btrfs_trans_handle *trans,
 	u64 old_root_bytenr;
 	struct btrfs_root *tree_root = root->fs_info->tree_root;
 
-	btrfs_write_dirty_block_groups(trans, root);
+	btrfs_write_dirty_block_groups(trans);
 	while(1) {
 		old_root_bytenr = btrfs_root_bytenr(&root->root_item);
 		if (old_root_bytenr == root->node->start)
@@ -76,7 +76,7 @@ static int update_cowonly_root(struct btrfs_trans_handle *trans,
 					&root->root_item);
 		if (ret < 0)
 			return ret;
-		btrfs_write_dirty_block_groups(trans, root);
+		btrfs_write_dirty_block_groups(trans);
 	}
 	return 0;
 }