diff --git a/src/file.cpp b/src/file.cpp
index 7022a94f..81fcb2d3 100644
--- a/src/file.cpp
+++ b/src/file.cpp
@@ -411,6 +411,7 @@ off_t OutputFile::unset_extent()
 {
     _offset = 0;
     _length = ::lseek(_fd, 0, SEEK_END);
+    bytes_written = _length;
     return _length;
 }