From a841bd48f886bd66e859e0cea2e43514244ae23a Mon Sep 17 00:00:00 2001
From: Howard Chen <howardsoc@google.com>
Date: Wed, 8 Jan 2020 16:59:40 +0800
Subject: [PATCH] Refine the first stage mount for DSU

* Open the ImageManager according to the saved DSU slot.
* Load the saved install_dir when it presents. This is required
  when installing to an external storage and the current code
  seems to break it.
* Remove an unnecessary C++ using.

Test: gsi_tool install
Bug: 144247097

Change-Id: I5b7be25787f235518a25abacefa612c33861f6ef
---
 fs_mgr/libfiemap/image_manager.cpp | 7 +++++++
 init/first_stage_mount.cpp         | 9 +++++++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/fs_mgr/libfiemap/image_manager.cpp b/fs_mgr/libfiemap/image_manager.cpp
index baa5de430..6a8b46e06 100644
--- a/fs_mgr/libfiemap/image_manager.cpp
+++ b/fs_mgr/libfiemap/image_manager.cpp
@@ -26,6 +26,7 @@
 #include <fs_mgr_dm_linear.h>
 #include <libdm/loop_control.h>
 #include <libfiemap/split_fiemap_writer.h>
+#include <libgsi/libgsi.h>
 
 #include "metadata.h"
 #include "utility.h"
@@ -34,6 +35,7 @@ namespace android {
 namespace fiemap {
 
 using namespace std::literals;
+using android::base::ReadFileToString;
 using android::base::unique_fd;
 using android::dm::DeviceMapper;
 using android::dm::DmDeviceState;
@@ -53,6 +55,11 @@ static constexpr char kTestImageMetadataDir[] = "/metadata/gsi/test";
 std::unique_ptr<ImageManager> ImageManager::Open(const std::string& dir_prefix) {
     auto metadata_dir = "/metadata/gsi/" + dir_prefix;
     auto data_dir = "/data/gsi/" + dir_prefix;
+    auto install_dir_file = gsi::DsuInstallDirFile(gsi::GetDsuSlot(dir_prefix));
+    std::string path;
+    if (ReadFileToString(install_dir_file, &path)) {
+        data_dir = path;
+    }
     return Open(metadata_dir, data_dir);
 }
 
diff --git a/init/first_stage_mount.cpp b/init/first_stage_mount.cpp
index e5e99e1e4..dccd23c44 100644
--- a/init/first_stage_mount.cpp
+++ b/init/first_stage_mount.cpp
@@ -58,7 +58,6 @@ using android::fs_mgr::ReadDefaultFstab;
 using android::fs_mgr::ReadFstabFromDt;
 using android::fs_mgr::SkipMountingPartitions;
 using android::fs_mgr::TransformFstabForDsu;
-using android::init::WriteFile;
 using android::snapshot::SnapshotManager;
 
 using namespace std::literals;
@@ -612,7 +611,13 @@ void FirstStageMount::UseDsuIfPresent() {
         }
         return InitRequiredDevices(std::move(devices));
     };
-    auto images = IImageManager::Open("dsu", 0ms);
+    std::string active_dsu;
+    if (!gsi::GetActiveDsu(&active_dsu)) {
+        LOG(ERROR) << "Failed to GetActiveDsu";
+        return;
+    }
+    LOG(INFO) << "DSU slot: " << active_dsu;
+    auto images = IImageManager::Open("dsu/" + active_dsu, 0ms);
     if (!images || !images->MapAllImages(init_devices)) {
         LOG(ERROR) << "DSU partition layout could not be instantiated";
         return;