--- x/fs/namei.c
+++ y/fs/namei.c
@@ -3494,6 +3494,7 @@ static struct dentry *lookup_open(struct
 			goto out_dput;
 		}
 
+		BUG_ON(!got_write);
 		error = dir_inode->i_op->create(idmap, dir_inode, dentry,
 						mode, open_flag & O_EXCL);
 		if (error)