してあった

had been done

→ 為る
phrase Rare #30,847
had been done Describes something someone had done in advance, with the result still in place. The person who did it is often left unstated.
JA: 会議室は予約してあった。
EN: The meeting room had been reserved.

さあ着いた予約してあったんだ!

Here we are. I had a reservation!

— ライフ・イズ・ビューティフル (1997)

注射器消毒してあったね?

The syringe had been sterilized, right?

— 東京物語 (1953)

新人俳優がハムレット役をすると広告してあった。

It was advertised that a newcomer would play Hamlet.

彼女は医者に診察の予約をしてあった。

She had an appointment with the doctor.

キャットの家の周りには、在庫を守るための柵がすでにかなりの範囲に設置してあった。

A fairly extensive fence had already been put up around Cat’s house to protect the supplies.