peerconn.go | 3 +++

diff --git a/peerconn.go b/peerconn.go
index 098d93fc46a6ba8f59833eaa9dfbce07200ae6e9..4ec0944ba7090f3a9ede320a3873488e0610728e 100644
--- a/peerconn.go
+++ b/peerconn.go
@@ -570,6 +570,9 @@ // This function seems to only used by Peer.request. It's all logic checks, so maybe we can no-op it
 // when we want to go fast.
 func (cn *Peer) shouldRequest(r RequestIndex) error {
 	pi := pieceIndex(r / cn.t.chunksPerRegularPiece())
+	if cn.requestState.Cancelled.Contains(r) {
+		return errors.New("request is cancelled and waiting acknowledgement")
+	}
 	if !cn.peerHasPiece(pi) {
 		return errors.New("requesting piece peer doesn't have")
 	}