diff --git a/migration/file.c b/migration/file.c
index 2bb8c64092..a903710f06 100644
--- a/migration/file.c
+++ b/migration/file.c
@@ -84,12 +84,19 @@ void file_start_outgoing_migration(MigrationState *s,
 
     trace_migration_file_outgoing(filename);
 
-    fioc = qio_channel_file_new_path(filename, O_CREAT | O_WRONLY | O_TRUNC,
-                                     0600, errp);
+    fioc = qio_channel_file_new_path(filename, O_CREAT | O_WRONLY, 0600, errp);
     if (!fioc) {
         return;
     }
 
+    if (ftruncate(fioc->fd, offset)) {
+        error_setg_errno(errp, errno,
+                         "failed to truncate migration file to offset %" PRIx64,
+                         offset);
+        object_unref(OBJECT(fioc));
+        return;
+    }
+
     outgoing_args.fname = g_strdup(filename);
 
     ioc = QIO_CHANNEL(fioc);