diff --git a/upload-pack.c b/upload-pack.c
index ab1981c72a..c3abf7ba65 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -10,7 +10,7 @@ static const char upload_pack_usage[] = "git-upload-pack [--strict] [--timeout=n
 #define THEY_HAVE (1U << 0)
 #define MAX_HAS 256
 #define MAX_NEEDS 256
-static int nr_has = 0, nr_needs = 0;
+static int nr_has = 0, nr_needs = 0, multi_ack = 0;
 static unsigned char has_sha1[MAX_HAS][20];
 static unsigned char needs_sha1[MAX_NEEDS][20];
 static unsigned int timeout = 0;
@@ -124,39 +124,28 @@ static int get_common_commits(void)
 		reset_timeout();
 
 		if (!len) {
-			packet_write(1, "NAK\n");
+			if (multi_ack || nr_has == 0)
+				packet_write(1, "NAK\n");
 			continue;
 		}
 		len = strip(line, len);
 		if (!strncmp(line, "have ", 5)) {
-			if (got_sha1(line+5, sha1)) {
-				packet_write(1, "ACK %s\n", sha1_to_hex(sha1));
-				break;
-			}
+			if (got_sha1(line+5, sha1) &&
+					(multi_ack || nr_has == 1))
+				packet_write(1, "ACK %s%s\n",
+					sha1_to_hex(sha1),
+					multi_ack && nr_has < MAX_HAS ?
+					" continue" : "");
 			continue;
 		}
 		if (!strcmp(line, "done")) {
+			if (nr_has > 0)
+				return 0;
 			packet_write(1, "NAK\n");
 			return -1;
 		}
 		die("git-upload-pack: expected SHA1 list, got '%s'", line);
 	}
-
-	for (;;) {
-		len = packet_read_line(0, line, sizeof(line));
-		reset_timeout();
-		if (!len)
-			continue;
-		len = strip(line, len);
-		if (!strncmp(line, "have ", 5)) {
-			got_sha1(line+5, sha1);
-			continue;
-		}
-		if (!strcmp(line, "done"))
-			break;
-		die("git-upload-pack: expected SHA1 list, got '%s'", line);
-	}
-	return 0;
 }
 
 static int receive_needs(void)
@@ -185,6 +174,10 @@ static int receive_needs(void)
 		if (strncmp("want ", line, 5) || get_sha1_hex(line+5, sha1_buf))
 			die("git-upload-pack: protocol error, "
 			    "expected to get sha, not '%s'", line);
+
+		if (strstr(line+45, "multi_ack"))
+			multi_ack = 1;
+
 		needs++;
 	}
 }