Two mistakes: 3♦ (East) and 4♠ (East)

3♦ is a reverse bid. Admittedly, it is somewhat tempered by the fact that partner has already shown at least 11 points, but it still promises around a good fifteen points.
Here, we are a bit too light for this bid, which could push our enthusiastic partner too high.
We should first simply repeat 2♠, which does not promise extra length in the suit. We can mention our Diamonds later in the auction if the opportunity arises.
4♠ is also a mistake. East must follow through on the initial approach and show the club control when partner starts exploring.

The correct sequence:

1♠ P 2♥ P
2♠ P 3♠ P
4♣ P 4♦ P
4♥ P 4♠ End