Or

        failed = 1;
        if ((res1 = lock(A) != 0)
	        if ((res2 = lock(B) != 0) {
		        if ((res3 = lock(C) != 0) {
				foo(res1, res2, res3);
				failed = 0;
			}
	if (res3 != 0)
        		release(C);
	if (res2 != 0)
        		release(B);
	if (res1 != 0)
        		release(A);

        return failed;

avoiding the goto.

Further, if release(nil) is implemented as a noop you can have

        failed = 1;
        if ((res1 = lock(A) != 0)
	        if ((res2 = lock(B) != 0) {
		        if ((res3 = lock(C) != 0) {
				foo(res1, res2, res3);
				failed = 0;
			}
	release(C);
	release(B);
	release(A);

        return failed;