diff --git a/object-file.c b/object-file.c
index b5bce03274..18dbf2a4e4 100644
--- a/object-file.c
+++ b/object-file.c
@@ -2000,6 +2000,28 @@ static int start_loose_object_common(struct strbuf *tmp_file,
 	return fd;
 }
 
+/**
+ * Common steps for the inner git_deflate() loop for writing loose
+ * objects. Returns what git_deflate() returns.
+ */
+static int write_loose_object_common(git_hash_ctx *c,
+				     git_zstream *stream, const int flush,
+				     unsigned char *in0, const int fd,
+				     unsigned char *compressed,
+				     const size_t compressed_len)
+{
+	int ret;
+
+	ret = git_deflate(stream, flush ? Z_FINISH : 0);
+	the_hash_algo->update_fn(c, in0, stream->next_in - in0);
+	if (write_buffer(fd, compressed, stream->next_out - compressed) < 0)
+		die(_("unable to write loose object file"));
+	stream->next_out = compressed;
+	stream->avail_out = compressed_len;
+
+	return ret;
+}
+
 /**
  * Common steps for loose object writers to end writing loose objects:
  *
@@ -2047,12 +2069,9 @@ static int write_loose_object(const struct object_id *oid, char *hdr,
 	stream.avail_in = len;
 	do {
 		unsigned char *in0 = stream.next_in;
-		ret = git_deflate(&stream, Z_FINISH);
-		the_hash_algo->update_fn(&c, in0, stream.next_in - in0);
-		if (write_buffer(fd, compressed, stream.next_out - compressed) < 0)
-			die(_("unable to write loose object file"));
-		stream.next_out = compressed;
-		stream.avail_out = sizeof(compressed);
+
+		ret = write_loose_object_common(&c, &stream, 1, in0, fd,
+						compressed, sizeof(compressed));
 	} while (ret == Z_OK);
 
 	if (ret != Z_STREAM_END)