Merge "Add a `--use_overlay` flag to allow disabling the overlay." am: ed616b2743

Original change: https://android-review.googlesource.com/c/device/google/cuttlefish/+/2175824

Change-Id: I82092601c57eaff7b8d12c5d4d6ed54973bc3ebb
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

6 files changed, 70 insertions, 19 deletions

diff --git a/host/commands/assemble_cvd/assemble_cvd.cc b/host/commands/assemble_cvd/assemble_cvd.cc
index d32751b8f..a0ce0e179 100644
--- a/host/commands/assemble_cvd/assemble_cvd.cc
+++ b/host/commands/assemble_cvd/assemble_cvd.cc
@@ -50,6 +50,8 @@ DEFINE_bool(resume, true, "Resume using the disk from the last session, if "
 DEFINE_int32(modem_simulator_count, 1,
              "Modem simulator count corresponding to maximum sim number");
 
+DECLARE_bool(use_overlay);
+
 namespace cuttlefish {
 namespace {
 
@@ -173,6 +175,12 @@ Result<const CuttlefishConfig*> InitFilesystemAndCreateConfig(
       auto os_builder = OsCompositeDiskBuilder(config, instance);
       creating_os_disk |= CF_EXPECT(os_builder.WillRebuildCompositeDisk());
     }
+    // TODO(schuffelen): Add smarter decision for when to delete runtime files.
+    // Files like NVChip are tightly bound to Android keymint and should be
+    // deleted when userdata is reset. However if the user has ever run without
+    // the overlay, then we want to keep this until userdata.img was externally
+    // replaced.
+    creating_os_disk &= FLAGS_use_overlay;
     if (FLAGS_resume && creating_os_disk) {
       LOG(INFO) << "Requested resuming a previous session (the default behavior) "
                 << "but the base images have changed under the overlay, making the "
diff --git a/host/commands/assemble_cvd/disk_flags.cc b/host/commands/assemble_cvd/disk_flags.cc
index a23633d61..46c4dcc09 100644
--- a/host/commands/assemble_cvd/disk_flags.cc
+++ b/host/commands/assemble_cvd/disk_flags.cc
@@ -93,6 +93,7 @@ DECLARE_string(initramfs_path);
 DECLARE_string(kernel_path);
 DECLARE_bool(resume);
 DECLARE_bool(protected_vm);
+DECLARE_bool(use_overlay);
 
 namespace cuttlefish {
 
@@ -149,91 +150,91 @@ std::vector<ImagePartition> GetOsCompositeDiskConfig() {
   partitions.push_back(ImagePartition{
       .label = "misc",
       .image_file_path = AbsolutePath(FLAGS_misc_image),
-      .read_only = true,
+      .read_only = FLAGS_use_overlay,
   });
   partitions.push_back(ImagePartition{
       .label = "boot_a",
       .image_file_path = AbsolutePath(FLAGS_boot_image),
-      .read_only = true,
+      .read_only = FLAGS_use_overlay,
   });
   partitions.push_back(ImagePartition{
       .label = "boot_b",
       .image_file_path = AbsolutePath(FLAGS_boot_image),
-      .read_only = true,
+      .read_only = FLAGS_use_overlay,
   });
   partitions.push_back(ImagePartition{
       .label = "init_boot_a",
       .image_file_path = AbsolutePath(FLAGS_init_boot_image),
-      .read_only = true,
+      .read_only = FLAGS_use_overlay,
   });
   partitions.push_back(ImagePartition{
       .label = "init_boot_b",
       .image_file_path = AbsolutePath(FLAGS_init_boot_image),
-      .read_only = true,
+      .read_only = FLAGS_use_overlay,
   });
   partitions.push_back(ImagePartition{
       .label = "vendor_boot_a",
       .image_file_path = AbsolutePath(FLAGS_vendor_boot_image),
-      .read_only = true,
+      .read_only = FLAGS_use_overlay,
   });
   partitions.push_back(ImagePartition{
       .label = "vendor_boot_b",
       .image_file_path = AbsolutePath(FLAGS_vendor_boot_image),
-      .read_only = true,
+      .read_only = FLAGS_use_overlay,
   });
   partitions.push_back(ImagePartition{
       .label = "vbmeta_a",
       .image_file_path = AbsolutePath(FLAGS_vbmeta_image),
-      .read_only = true,
+      .read_only = FLAGS_use_overlay,
   });
   partitions.push_back(ImagePartition{
       .label = "vbmeta_b",
       .image_file_path = AbsolutePath(FLAGS_vbmeta_image),
-      .read_only = true,
+      .read_only = FLAGS_use_overlay,
   });
   partitions.push_back(ImagePartition{
       .label = "vbmeta_system_a",
       .image_file_path = AbsolutePath(FLAGS_vbmeta_system_image),
-      .read_only = true,
+      .read_only = FLAGS_use_overlay,
   });
   partitions.push_back(ImagePartition{
       .label = "vbmeta_system_b",
       .image_file_path = AbsolutePath(FLAGS_vbmeta_system_image),
-      .read_only = true,
+      .read_only = FLAGS_use_overlay,
   });
   partitions.push_back(ImagePartition{
       .label = "super",
       .image_file_path = AbsolutePath(FLAGS_super_image),
-      .read_only = true,
+      .read_only = FLAGS_use_overlay,
   });
   partitions.push_back(ImagePartition{
       .label = "userdata",
       .image_file_path = AbsolutePath(FLAGS_data_image),
-      .read_only = true,
+      .read_only = FLAGS_use_overlay,
   });
   partitions.push_back(ImagePartition{
       .label = "metadata",
       .image_file_path = AbsolutePath(FLAGS_metadata_image),
-      .read_only = true,
+      .read_only = FLAGS_use_overlay,
   });
   if (!FLAGS_otheros_root_image.empty()) {
     partitions.push_back(ImagePartition{
         .label = "otheros_esp",
         .image_file_path = AbsolutePath(FLAGS_otheros_esp_image),
         .type = kEfiSystemPartition,
-        .read_only = true,
+        .read_only = FLAGS_use_overlay,
     });
     partitions.push_back(ImagePartition{
         .label = "otheros_root",
         .image_file_path = AbsolutePath(FLAGS_otheros_root_image),
-        .read_only = true,
+        .read_only = FLAGS_use_overlay,
     });
   }
   if (!FLAGS_ap_rootfs_image.empty()) {
     partitions.push_back(ImagePartition{
         .label = "ap_rootfs",
         .image_file_path = AbsolutePath(FLAGS_ap_rootfs_image),
-        .read_only = true,
+        .read_only = FLAGS_use_overlay,
     });
   }
   return partitions;
diff --git a/host/commands/assemble_cvd/flags.cc b/host/commands/assemble_cvd/flags.cc
index 4b4a30a61..1a74d83db 100644
--- a/host/commands/assemble_cvd/flags.cc
+++ b/host/commands/assemble_cvd/flags.cc
@@ -347,6 +347,10 @@ DEFINE_uint32(camera_server_port, 0, "camera vsock port");
 
 DEFINE_string(userdata_format, "f2fs", "The userdata filesystem format");
 
+DEFINE_bool(use_overlay, true,
+            "Capture disk writes an overlay. This is a "
+            "prerequisite for powerwash_cvd or multiple instances.");
+
 DECLARE_string(assembly_dir);
 DECLARE_string(boot_image);
 DECLARE_string(system_image_dir);
@@ -777,6 +781,9 @@ CuttlefishConfig InitializeCuttlefishConfiguration(
   auto instance_nums = InstanceNumsCalculator().FromGlobalGflags().Calculate();
   CHECK(instance_nums.ok()) << instance_nums.error();
 
+  CHECK(FLAGS_use_overlay || instance_nums->size() == 1)
+      << "`--use_overlay=false` is incompatible with multiple instances";
+
   bool is_first_instance = true;
   int instance_index = 0;
   for (const auto& num : *instance_nums) {
@@ -872,6 +879,7 @@ CuttlefishConfig InitializeCuttlefishConfiguration(
     os_overlay &= !FLAGS_protected_vm;
     // Gem5 already uses CoW wrappers around disk images
     os_overlay &= FLAGS_vm_manager != Gem5Manager::name();
+    os_overlay &= FLAGS_use_overlay;
     if (os_overlay) {
       auto path = const_instance.PerInstancePath("overlay.img");
       virtual_disk_paths.push_back(path);
diff --git a/host/commands/run_cvd/server_loop.cpp b/host/commands/run_cvd/server_loop.cpp
index cbf8b1cbd..d67a72051 100644
--- a/host/commands/run_cvd/server_loop.cpp
+++ b/host/commands/run_cvd/server_loop.cpp
@@ -18,6 +18,7 @@
 
 #include <unistd.h>
 
+#include <algorithm>
 #include <string>
 
 #include <fruit/fruit.h>
@@ -112,6 +113,15 @@ class ServerLoopImpl : public ServerLoop,
           }
           case LauncherAction::kPowerwash: {
             LOG(INFO) << "Received a Powerwash request from the monitor socket";
+            const auto& disks = instance_.virtual_disk_paths();
+            auto overlay = instance_.PerInstancePath("overlay.img");
+            if (std::find(disks.begin(), disks.end(), overlay) == disks.end()) {
+              LOG(ERROR) << "Powerwash unsupported with --use_overlay=false";
+              auto response = LauncherResponse::kError;
+              client->Write(&response, sizeof(response));
+              break;
+            }
+
             auto stop = process_monitor.StopMonitoredProcesses();
             if (!stop.ok()) {
               LOG(ERROR) << "Stopping processes failed:\n" << stop.error();
diff --git a/host/commands/start/main.cc b/host/commands/start/main.cc
index 4317effb0..ea49ab056 100644
--- a/host/commands/start/main.cc
+++ b/host/commands/start/main.cc
@@ -58,6 +58,9 @@ DEFINE_string(verbosity, "INFO", "Console logging verbosity. Options are VERBOSE
 DEFINE_string(file_verbosity, "DEBUG",
               "Log file logging verbosity. Options are VERBOSE,DEBUG,INFO,"
               "WARNING,ERROR");
+DEFINE_bool(use_overlay, true,
+            "Capture disk writes an overlay. This is a "
+            "prerequisite for powerwash_cvd or multiple instances.");
 
 namespace {
 
@@ -200,6 +203,22 @@ int main(int argc, char** argv) {
       cuttlefish::InstanceNumsCalculator().FromGlobalGflags().Calculate();
   CHECK(instance_nums.ok()) << instance_nums.error();
 
+  if (cuttlefish::CuttlefishConfig::ConfigExists()) {
+    auto previous_config = cuttlefish::CuttlefishConfig::Get();
+    CHECK(previous_config);
+    CHECK(previous_config->Instances().size() > 0);
+    auto previous_instance = previous_config->Instances()[0];
+    const auto& disks = previous_instance.virtual_disk_paths();
+    auto overlay = previous_instance.PerInstancePath("overlay.img");
+    auto used_overlay =
+        std::find(disks.begin(), disks.end(), overlay) != disks.end();
+    CHECK(used_overlay == FLAGS_use_overlay)
+        << "Cannot transition between different values of --use_overlay "
+        << "(Previous = " << used_overlay << ", current = " << FLAGS_use_overlay
+        << "). To fix this, delete \"" << previous_config->root_dir()
+        << "\" and any image files.";
+  }
+
   CHECK(instance_nums->size() > 0) << "Expected at least one instance";
   auto instance_num_str = std::to_string(*instance_nums->begin());
   setenv("CUTTLEFISH_INSTANCE", instance_num_str.c_str(), /* overwrite */ 1);
diff --git a/host/libs/config/data_image.cpp b/host/libs/config/data_image.cpp
index 8932c7c6a..f93c375cc 100644
--- a/host/libs/config/data_image.cpp
+++ b/host/libs/config/data_image.cpp
@@ -282,10 +282,15 @@ class InitializeDataImageImpl : public InitializeDataImage {
       }
       return DataImageAction::kCreateImage;
     }
-    if (GetFsType(data_path_.Path()) != config_.userdata_format()) {
+    if (config_.data_policy() == kDataPolicyUseExisting) {
+      return DataImageAction::kNoAction;
+    }
+    auto current_fs_type = GetFsType(data_path_.Path());
+    if (current_fs_type != config_.userdata_format()) {
       CF_EXPECT(config_.data_policy() == kDataPolicyResizeUpTo,
                 "Changing the fs format is incompatible with -data_policy="
-                    << kDataPolicyResizeUpTo);
+                    << kDataPolicyResizeUpTo << " (\"" << current_fs_type
+                    << "\" != \"" << config_.userdata_format() << "\")");
       return DataImageAction::kCreateImage;
     }
     if (config_.data_policy() == kDataPolicyResizeUpTo) {