isofs: inode leak on mount failure

d_alloc_root() failure leaves root inode leaked...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/isofs/inode.c b/fs/isofs/inode.c
index 7b99f5f..bd62c76 100644
--- a/fs/isofs/inode.c
+++ b/fs/isofs/inode.c
@@ -948,8 +948,11 @@
 
 	/* get the root dentry */
 	s->s_root = d_alloc_root(inode);
-	if (!(s->s_root))
-		goto out_no_root;
+	if (!(s->s_root)) {
+		iput(inode);
+		error = -ENOMEM;
+		goto out_no_inode;
+	}
 
 	kfree(opt.iocharset);