Don't truncate files if we don't need to extend them

Don't truncate files if we don't need to extend them.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/filesetup.c b/filesetup.c
index 210cd2f..34130b8 100644
--- a/filesetup.c
+++ b/filesetup.c
@@ -50,14 +50,14 @@
 		return 1;
 	}
 
+	if (!new_layout)
+		goto done;
+
 	if (ftruncate(f->fd, f->real_file_size) == -1) {
 		td_verror(td, errno, "ftruncate");
 		goto err;
 	}
 
-	if (!new_layout)
-		goto done;
-
 	if (posix_fallocate(f->fd, 0, f->real_file_size) < 0) {
 		td_verror(td, errno, "posix_fallocate");
 		goto err;