diff -Nura libmicrohttpd/src/daemon/connection.c libmicrohttpdNew/src/daemon/connection.c
--- libmicrohttpd/src/daemon/connection.c	2011-05-16 11:39:38.000000000 +0800
+++ libmicrohttpdNew/src/daemon/connection.c	2011-05-16 11:47:25.976324170 +0800
@@ -1363,14 +1363,18 @@
         }
       else
         {
-          /* no chunked encoding, give all to the client */
-          if ( (0 != connection->remaining_upload_size) && 
-	       (MHD_SIZE_UNKNOWN != connection->remaining_upload_size) )
+          if ( (0 != connection->remaining_upload_size) 
+                  && (MHD_SIZE_UNKNOWN != connection->remaining_upload_size)
+                  && (connection->remaining_upload_size < available)  )
 	    {
               processed = connection->remaining_upload_size;
 	    }
           else
 	    {
+              /**
+               * 1. no chunked encoding, give all to the client
+               * 2. client may send large chunked data, but only a smaller part is available at one time.
+               */
               processed = available;
 	    }
         }