From cadad290a79d5b0a30add935aaadab7c1b1ef5e9 Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers@google.com>
Date: Tue, 26 Nov 2024 02:56:24 +0000
Subject: [PATCH] Fix the dm-verity Merkle tree caches to not expire so quickly

Bug: 335233956
Test: cat /sys/module/dm_bufio/parameters/max_age_seconds
Change-Id: I20e4df7dd3eb2ac1f462510e900568e946195faf
---
 rootdir/init.rc | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/rootdir/init.rc b/rootdir/init.rc
index f00479ece..58f0495e6 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -54,6 +54,10 @@ on early-init
     mkdir /linkerconfig/bootstrap 0755
     mkdir /linkerconfig/default 0755
 
+    # Greatly extend dm-verity's Merkle tree cache timeout.  The default timeout
+    # is much too short and is unnecessary, given that there is also a shrinker.
+    write /sys/module/dm_bufio/parameters/max_age_seconds 86400
+
     # Disable dm-verity hash prefetching, since it doesn't help performance
     # Read more in b/136247322
     write /sys/module/dm_verity/parameters/prefetch_cluster 0