From dea6f7c2a53b0fc970f28d8c45bfc390ef69cff2 Mon Sep 17 00:00:00 2001
From: David Anderson <dvander@google.com>
Date: Mon, 28 Oct 2024 19:47:09 -0700
Subject: [PATCH] Fix overlayfs on page cf page agnostic builds.

Hardcode 4096 block size for f2fs on x86/64.

Bug: 375531898
Test: adb_remount_test.sh
Change-Id: I9b55f7caf1b77f235168664be2f310bb3bb0d179
---
 fs_mgr/fs_mgr.cpp                   | 8 ++++++++
 fs_mgr/fs_mgr_overlayfs_control.cpp | 4 +---
 fs_mgr/include/fs_mgr.h             | 3 +++
 3 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/fs_mgr/fs_mgr.cpp b/fs_mgr/fs_mgr.cpp
index fbd990b96..e39ffe70c 100644
--- a/fs_mgr/fs_mgr.cpp
+++ b/fs_mgr/fs_mgr.cpp
@@ -2314,6 +2314,14 @@ std::string fs_mgr_get_context(const std::string& mount_point) {
     return context;
 }
 
+int fs_mgr_f2fs_ideal_block_size() {
+#if defined(__i386__) || defined(__x86_64__)
+    return 4096;
+#else
+    return getpagesize();
+#endif
+}
+
 namespace android {
 namespace fs_mgr {
 
diff --git a/fs_mgr/fs_mgr_overlayfs_control.cpp b/fs_mgr/fs_mgr_overlayfs_control.cpp
index 08ad80caa..489b32e7e 100644
--- a/fs_mgr/fs_mgr_overlayfs_control.cpp
+++ b/fs_mgr/fs_mgr_overlayfs_control.cpp
@@ -387,10 +387,8 @@ bool MakeScratchFilesystem(const std::string& scratch_device) {
     auto command = ""s;
     if (!access(kMkF2fs, X_OK) && fs_mgr_filesystem_available("f2fs")) {
         fs_type = "f2fs";
-        command = kMkF2fs + " -w "s;
-        command += std::to_string(getpagesize());
         command = kMkF2fs + " -b "s;
-        command += std::to_string(getpagesize());
+        command += std::to_string(fs_mgr_f2fs_ideal_block_size());
         command += " -f -d1 -l" + android::base::Basename(kScratchMountPoint);
     } else if (!access(kMkExt4, X_OK) && fs_mgr_filesystem_available("ext4")) {
         fs_type = "ext4";
diff --git a/fs_mgr/include/fs_mgr.h b/fs_mgr/include/fs_mgr.h
index 9cfa93f78..79690874e 100644
--- a/fs_mgr/include/fs_mgr.h
+++ b/fs_mgr/include/fs_mgr.h
@@ -137,3 +137,6 @@ bool fs_mgr_mount_overlayfs_fstab_entry(const android::fs_mgr::FstabEntry& entry
 // File name used to track if encryption was interrupted, leading to a known bad fs state
 std::string fs_mgr_metadata_encryption_in_progress_file_name(
         const android::fs_mgr::FstabEntry& entry);
+
+// Returns the ideal block size for make_f2fs. Returns -1 on failure.
+int fs_mgr_f2fs_ideal_block_size();