mysql_client_server_protocol.h :

changed gw_receive_backend_auth declaration to return int instead of boolean.
mysql_backend.c:
	gw_read_backend_event calls gw_receive_backend_auth which either fails (== -1), succeeds with nothing to read (== 0) or succeeds (== 1). For each case there is handling. If dcb_read succeeds without read bytes, return asap.
mysql_client.c:
	gw_error_client_event, gw_client_close, gw_client_hangup_event : all close client dcb but now they also close backend dcb.
mysql_common.c:
	gw_receive_backend_auth, return -1, 0, or 1 if read from backend failed, was empty, or succeed, respectively.:

server/core/gw_utils.c

@@ -135,6 +135,7 @@ int gw_read_gwbuff(DCB *dcb, GWBUF **head, int b) {
 
 	if (b <= 0) {
 		//fprintf(stderr, "||| read_gwbuff called with 0 bytes for %i, closing\n", dcb->fd);
+                ss_dassert(false);
 #if 0
 		dcb->func.close(dcb);
 #endif