is one piece episode 378 filler?

Everyone is happy that their shadows are back, and Nami is really happy with the pile of treasure they find. The crew carries lots of food with them down to the courtyard.

While everyone starts enjoying it two men say they saw what happened to Zoro after everyone else, including Sanji, was knocked out. Sanji drags them out and asks what happened.

After being told about Zoro risking his life and taking in all of Luffy's pain from their time on Thriller Bark so far, he makes them swear not to tell anyone, especially Luffy since he would get sad at the thought that all the pain, he took for his f…