Fixed the sending of large files with older rsync versions by

handling the old block-size limit for protocols < 29.

NEWS

@@ -39,11 +39,14 @@ Changes since 3.0.2:
     - Fixed a problem with how a destination path with a trailing slash or
       a trailing dot-dir was compared against the daemon excludes.
 
+    - Fixed the sending of large (size > 16GB) files when talking to an older
+      rsync (protocols < 30):  we now use a compatible block size limit.
+
     - If a file's length is so huge that we overflow a checksum buffer count
       (i.e. several hundred TB), warn the user and avoid sending an invalid
       checksum struct over the wire.
 
-    - If an source arg is excluded, --relative no longer adds the excluded
+    - If a source arg is excluded, --relative no longer adds the excluded
       arg's implied dirs to the transfer.  This fix also made the exclude
       check happen in the better place in the sending code.
 

generator.c

@@ -763,11 +763,12 @@ static void sum_sizes_sqroot(struct sum_struct *sum, int64 len)
 	else if (len <= BLOCK_SIZE * BLOCK_SIZE)
 		blength = BLOCK_SIZE;
 	else {
+		int32 max_blength = protocol_version < 30 ? OLD_MAX_BLOCK_SIZE : MAX_BLOCK_SIZE;
 		int32 c;
 		int cnt;
 		for (c = 1, l = len, cnt = 0; l >>= 2; c <<= 1, cnt++) {}
-		if (cnt >= 31 || c >= MAX_BLOCK_SIZE)
-			blength = MAX_BLOCK_SIZE;
+		if (c < 0 || c >= max_blength)
+			blength = max_blength;
 		else {
 		    blength = 0;
 		    do {

io.c

@@ -1354,6 +1354,7 @@ int read_vstring(int f, char *buf, int bufsize)
  * called by both the sender and the receiver. */
 void read_sum_head(int f, struct sum_struct *sum)
 {
+	int32 max_blength = protocol_version < 30 ? OLD_MAX_BLOCK_SIZE : MAX_BLOCK_SIZE;
 	sum->count = read_int(f);
 	if (sum->count < 0) {
 		rprintf(FERROR, "Invalid checksum count %ld [%s]\n",
@@ -1361,7 +1362,7 @@ void read_sum_head(int f, struct sum_struct *sum)
 		exit_cleanup(RERR_PROTOCOL);
 	}
 	sum->blength = read_int(f);
-	if (sum->blength < 0 || sum->blength > MAX_BLOCK_SIZE) {
+	if (sum->blength < 0 || sum->blength > max_blength) {
 		rprintf(FERROR, "Invalid block length %ld [%s]\n",
 			(long)sum->blength, who_am_i());
 		exit_cleanup(RERR_PROTOCOL);

rsync.h

@@ -129,6 +129,9 @@
 #define IO_BUFFER_SIZE (4092)
 #define MAX_BLOCK_SIZE ((int32)1 << 17)
 
+/* For compatibility with older rsyncs */
+#define OLD_MAX_BLOCK_SIZE ((int32)1 << 29)
+
 #define IOERR_GENERAL	(1<<0) /* For backward compatibility, this must == 1 */
 #define IOERR_VANISHED	(1<<1)
 #define IOERR_DEL_LIMIT (1<<2)