From 8de4c9250eeba3b80e8f7132ab529906ce8040f6 Mon Sep 17 00:00:00 2001
From: Maxwell Guo <cclive1601@gmail.com>
Date: Tue, 17 Jun 2025 10:06:38 +0800
Subject: [PATCH] Make Commitlog flush data safely in Direct IO mode

patch by Maxwell Guo; reviewed by Ariel Weisberg for CASSANDRA-20692
---
 CHANGES.txt                                                | 1 +
 .../org/apache/cassandra/db/commitlog/DirectIOSegment.java | 7 ++++++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/CHANGES.txt b/CHANGES.txt
index 6935dd4489..947891e3f2 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,4 +1,5 @@
 5.0.5
+ * Make Commitlog flush data safely in Direct IO mode (CASSANDRA-20692)
  * Get SAI MemtableIndex refs before SSTableIndex refs at query time (CASSANDRA-20709)
  * Fix MAX_SEGMENT_SIZE < chunkSize in MmappedRegions::updateState (CASSANDRA-20636)
  * Full Java 17 support (CASSANDRA-20681)
diff --git a/src/java/org/apache/cassandra/db/commitlog/DirectIOSegment.java b/src/java/org/apache/cassandra/db/commitlog/DirectIOSegment.java
index b4819aa201..fec799ce9d 100644
--- a/src/java/org/apache/cassandra/db/commitlog/DirectIOSegment.java
+++ b/src/java/org/apache/cassandra/db/commitlog/DirectIOSegment.java
@@ -177,7 +177,12 @@ public class DirectIOSegment extends CommitLogSegment
         public DirectIOSegment build()
         {
             return new DirectIOSegment(segmentManager,
-                                       path -> FileChannel.open(path, StandardOpenOption.WRITE, StandardOpenOption.READ, StandardOpenOption.CREATE, ExtendedOpenOption.DIRECT),
+                                       path -> FileChannel.open(path,
+                                                                StandardOpenOption.WRITE,
+                                                                StandardOpenOption.READ,
+                                                                StandardOpenOption.CREATE,
+                                                                StandardOpenOption.DSYNC,
+                                                                ExtendedOpenOption.DIRECT),
                                        fsBlockSize);
         }