From 75ef41058dc20ca913f25f3edf513ea41cb72ed0 Mon Sep 17 00:00:00 2001
From: antirez <antirez@gmail.com>
Date: Fri, 4 Jul 2014 15:35:01 +0200
Subject: [PATCH] Use a timeout when reading parent ack from AOF child.

---
 src/aof.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/aof.c b/src/aof.c
index 868a3297..ac5fb8aa 100644
--- a/src/aof.c
+++ b/src/aof.c
@@ -1040,9 +1040,15 @@ int rewriteAppendOnlyFile(char *filename) {
     }
 
     /* Ask the master to stop sending diffs. */
-    write(server.aof_pipe_write_ack_to_parent,"!",1);
-    if (read(server.aof_pipe_read_ack_from_parent,&byte,1) != 1 ||
+    if (write(server.aof_pipe_write_ack_to_parent,"!",1) != 1) goto werr;
+    if (anetNonBlock(NULL,server.aof_pipe_read_ack_from_parent) != ANET_OK)
+        goto werr;
+    /* We read the ACK from the server using a 10 seconds timeout. Normally
+     * it should reply ASAP, but just in case we lose its reply, we are sure
+     * the child will eventually get terminated. */
+    if (syncRead(server.aof_pipe_read_ack_from_parent,&byte,1,5000) != 1 ||
         byte != '!') goto werr;
+    redisLog(REDIS_NOTICE,"Parent agreed to stop sending diffs. Finalizing AOF...");
 
     /* Read the final diff if any. */
     aofReadDiffFromParent();