diff --git a/transaction.h b/transaction.h
index 0c41af51..738eebd1 100644
--- a/transaction.h
+++ b/transaction.h
@@ -22,6 +22,8 @@
 #include "kerncompat.h"
 #include "ctree.h"
 
+#include "messages.h"
+
 struct btrfs_trans_handle {
 	u64 transid;
 	u64 alloc_exclude_start;
@@ -37,9 +39,18 @@ btrfs_start_transaction(struct btrfs_root *root, int num_blocks)
 	struct btrfs_fs_info *fs_info = root->fs_info;
 	struct btrfs_trans_handle *h = malloc(sizeof(*h));
 
-	BUG_ON(!h);
-	BUG_ON(root->commit_root);
-	BUG_ON(fs_info->running_transaction);
+	if (!h)
+		return ERR_PTR(-ENOMEM);
+	if (root->commit_root) {
+		error("commit_root aleady set when starting transaction");
+		kfree(h);
+		return ERR_PTR(-EINVAL);
+	}
+	if (fs_info->running_transaction) {
+		error("attempt to start transaction over already running one");
+		kfree(h);
+		return ERR_PTR(-EINVAL);
+	}
 	fs_info->running_transaction = h;
 	fs_info->generation++;
 	h->transid = fs_info->generation;