storage/sqlite/direct.go | 2 ++

diff --git a/storage/sqlite/direct.go b/storage/sqlite/direct.go
index dba48259dd74cc7e2d7e88501b84c459a4ebdd12..709102bfb01f282ed3e525683ec0afb3e1eb5c49 100644
--- a/storage/sqlite/direct.go
+++ b/storage/sqlite/direct.go
@@ -221,6 +221,8 @@ 	delete(p.blobs, p.name)
 }
 
 func (p piece) MarkNotComplete() error {
+	p.l.Lock()
+	defer p.l.Unlock()
 	return sqlitex.Exec(p.conn, "update blob set verified=false where name=?", nil, p.name)
 }