diff --git a/builtin-pack-objects.c b/builtin-pack-objects.c
index 7079fab7d..7234d76f6 100644
--- a/builtin-pack-objects.c
+++ b/builtin-pack-objects.c
@@ -1293,7 +1293,7 @@ static int try_delta(struct unpacked *trg, struct unpacked *src,
 		max_size = trg_entry->delta_size;
 		ref_depth = trg->depth;
 	}
-	max_size = max_size * (max_depth - src->depth) /
+	max_size = (uint64_t)max_size * (max_depth - src->depth) /
 						(max_depth - ref_depth + 1);
 	if (max_size == 0)
 		return 0;
diff --git a/sha1_file.c b/sha1_file.c
index b63f842cb..3d93d936e 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -2298,7 +2298,7 @@ static void close_sha1_file(int fd)
 		fsync_or_die(fd, "sha1 file");
 	fchmod(fd, 0444);
 	if (close(fd) != 0)
-		die("unable to write sha1 file");
+		die("error when closing sha1 file (%s)", strerror(errno));
 }
 
 /* Size of directory component, including the ending '/' */