disable-zfs-dmu-offset-next-sync-by-default-v2-2.patch

From 3ba4ff328ab001d88d7714087d8a89687bc68312 Mon Sep 17 00:00:00 2001
From: Andrew Marshall <andrew@johnandrewmarshall.com>
Date: Sun, 26 Nov 2023 12:46:18 -0500
Subject: [PATCH] Disable zfs_dmu_offset_next_sync tunable by default

This helps mitigate a data corruption bug. This was previously defaulted
to zero, so doing so seems safe.

See https://github.com/openzfs/zfs/issues/11900
See https://github.com/openzfs/zfs/issues/15526
---
 man/man4/zfs.4   | 2 +-
 module/zfs/dmu.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/man/man4/zfs.4 b/man/man4/zfs.4
index 4ec52a2fb..2a69a8f54 100644
--- a/man/man4/zfs.4
+++ b/man/man4/zfs.4
@@ -1660,7 +1660,7 @@ Allow no-operation writes.
 The occurrence of nopwrites will further depend on other pool properties
 .Pq i.a. the checksumming and compression algorithms .
 .
-.It Sy zfs_dmu_offset_next_sync Ns = Ns Sy 1 Ns | Ns 0 Pq int
+.It Sy zfs_dmu_offset_next_sync Ns = Ns Sy 0 Ns | Ns 1 Pq int
 Enable forcing TXG sync to find holes.
 When enabled forces ZFS to sync data when
 .Sy SEEK_HOLE No or Sy SEEK_DATA
diff --git a/module/zfs/dmu.c b/module/zfs/dmu.c
index ddb29020b..5d37b6f92 100644
--- a/module/zfs/dmu.c
+++ b/module/zfs/dmu.c
@@ -82,7 +82,7 @@ static uint_t zfs_per_txg_dirty_frees_percent = 30;
  * Disabling this option will result in holes never being reported in dirty
  * files which is always safe.
  */
-static int zfs_dmu_offset_next_sync = 1;
+static int zfs_dmu_offset_next_sync = 0;
 
 /*
  * Limit the amount we can prefetch with one call to this amount.  This
-- 
2.42.0