storage/mmap.go | 5 ++++-

diff --git a/storage/mmap.go b/storage/mmap.go
index 8bce4dc778827acea4096c57ff5dc37e479d1750..53d8680c5a098a77fb29ec7733a2fa6504d69658 100644
--- a/storage/mmap.go
+++ b/storage/mmap.go
@@ -78,7 +78,10 @@ 	return metainfo.PieceKey{me.ih, me.p.Index()}
 }
 
 func (sp mmapStoragePiece) Completion() Completion {
-	c, _ := sp.pc.Get(sp.pieceKey())
+	c, err := sp.pc.Get(sp.pieceKey())
+	if err != nil {
+		panic(err)
+	}
 	return c
 }