diff --git a/multipart/src/main.rs b/multipart/src/main.rs
index aa3c8b97..da7b929a 100644
--- a/multipart/src/main.rs
+++ b/multipart/src/main.rs
@@ -23,13 +23,12 @@ pub fn save_file(field: Field) -> impl Future<Item = i64, Error = Error> {
                 // fs operations are blocking, we have to execute writes
                 // on threadpool
                 web::block(move || {
-                    acc += file
-                        .write_all(bytes.as_ref())
-                        .map(|_| acc + bytes.len() as i64)
+                    file.write_all(bytes.as_ref())
                         .map_err(|e| {
                             println!("file.write_all failed: {:?}", e);
                             MultipartError::Payload(error::PayloadError::Io(e))
                         })?;
+                    acc += bytes.len() as i64;
                     Ok((file, acc))
                 })
                 .map_err(|e: error::BlockingError<MultipartError>| {