configfs: call drop_link() to cleanup after create_link() failure

When allow_link() succeeds but create_link() fails, the subsystem is not
informed of the failure.

This patch fixes this by calling drop_link() on create_link() failures.

Signed-off-by: Louis Rilling <Louis.Rilling@kerlabs.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>

fs/configfs/symlink.c

@@ -140,8 +140,12 @@ int configfs_symlink(struct inode *dir, struct dentry *dentry, const char *symna
 		goto out_put;
 
 	ret = type->ct_item_ops->allow_link(parent_item, target_item);
-	if (!ret)
+	if (!ret) {
 		ret = create_link(parent_item, target_item, dentry);
+		if (ret && type->ct_item_ops->drop_link)
+			type->ct_item_ops->drop_link(parent_item,
+						     target_item);
+	}
 
 	config_item_put(target_item);
 	path_put(&nd.path);