Ensure FASTOP messages get an ACK reply so that the client can be sure the server
recieved them. This means if connections are terminated, data isn't lost.

RP 2017/9/22

Upstream-Status: Submitted

Index: pseudo-1.8.2/pseudo_client.c
===================================================================
--- pseudo-1.8.2.orig/pseudo_client.c
+++ pseudo-1.8.2/pseudo_client.c
@@ -1331,21 +1331,19 @@ pseudo_client_request(pseudo_msg_t *msg,
 		 * indicating a successful send.
 		 */
 		pseudo_debug(PDBGF_CLIENT | PDBGF_VERBOSE, "sent!\n");
-		if (msg->type != PSEUDO_MSG_FASTOP) {
-			response = pseudo_msg_receive(connect_fd);
-			if (!response) {
-				pseudo_debug(PDBGF_CLIENT, "expected response did not occur; retrying\n");
+		response = pseudo_msg_receive(connect_fd);
+		if (!response) {
+			pseudo_debug(PDBGF_CLIENT, "expected response did not occur; retrying\n");
+		} else {
+			if (response->type != PSEUDO_MSG_ACK) {
+				pseudo_debug(PDBGF_CLIENT, "got non-ack response %d\n", response->type);
+				return 0;
+			} else if (msg->type != PSEUDO_MSG_FASTOP) {
+				pseudo_debug(PDBGF_CLIENT | PDBGF_VERBOSE, "got response type %d\n", response->type);
+				return response;
 			} else {
-				if (response->type != PSEUDO_MSG_ACK) {
-					pseudo_debug(PDBGF_CLIENT, "got non-ack response %d\n", response->type);
-					return 0;
-				} else {
-					pseudo_debug(PDBGF_CLIENT | PDBGF_VERBOSE, "got response type %d\n", response->type);
-					return response;
-				}
+				return 0;
 			}
-		} else {
-			return 0;
 		}
 	}
 	pseudo_diag("pseudo: server connection persistently failed, aborting.\n");
Index: pseudo-1.8.2/pseudo_server.c
===================================================================
--- pseudo-1.8.2.orig/pseudo_server.c
+++ pseudo-1.8.2/pseudo_server.c
@@ -463,6 +463,11 @@ close_client(int client) {
 			--highest_client;
 }
 
+static pseudo_msg_t server_fastop_reply = { 
+        .type = PSEUDO_MSG_ACK,
+        .op = OP_NONE,
+};
+
 /* Actually process a request.
  */
 static int
@@ -515,8 +520,14 @@ serve_client(int i) {
 		 * pseudo_server_response.
 		 */
 		if (in->type != PSEUDO_MSG_SHUTDOWN) {
-                        if (in->type == PSEUDO_MSG_FASTOP)
+                        if (in->type == PSEUDO_MSG_FASTOP) {
                                 send_response = 0;
+                                /* For fastops we reply now to say we got the data */
+                                if ((rc = pseudo_msg_send(clients[i].fd, &server_fastop_reply, 0, NULL)) != 0) {
+                                            pseudo_debug(PDBGF_SERVER, "failed to send fastop ack to client %d [%d]: %d (%s)\n",
+                                                    i, (int) clients[i].pid, rc, strerror(errno));
+                                }
+                        }
 			/* most messages don't need these, but xattr may */
 			response_path = 0;
 			response_pathlen = -1;