Add IGsiService::suggestScratchSize() am: 721a0e4b06 am: 0958afc108

Original change: https://android-review.googlesource.com/c/platform/system/gsid/+/1536726

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I0df1b06ecd0944f76e894864fada03461c9a6e9c

4 files changed, 33 insertions, 0 deletions

diff --git a/Android.bp b/Android.bp
index 8e3acaa..cb6c077 100644
--- a/Android.bp
+++ b/Android.bp
@@ -101,6 +101,9 @@ cc_binary {
         "libc++fs",
         "libvold_binder",
     ],
+    header_libs: [
+        "libstorage_literals_headers",
+    ],
     target: {
         android: {
             shared_libs: [
diff --git a/aidl/android/gsi/IGsiService.aidl b/aidl/android/gsi/IGsiService.aidl
index 8b38504..f706098 100644
--- a/aidl/android/gsi/IGsiService.aidl
+++ b/aidl/android/gsi/IGsiService.aidl
@@ -229,4 +229,9 @@ interface IGsiService {
      * @return              0 on success, an error code on failure.
      */
     int getAvbPublicKey(out AvbPublicKey dst);
+
+    /**
+     * Returns the suggested scratch partition size for overlayFS.
+     */
+    long suggestScratchSize();
 }
diff --git a/gsi_service.cpp b/gsi_service.cpp
index 14ef1d4..6d310a4 100644
--- a/gsi_service.cpp
+++ b/gsi_service.cpp
@@ -16,6 +16,7 @@
 
 #include "gsi_service.h"
 
+#include <sys/statvfs.h>
 #include <sys/vfs.h>
 #include <unistd.h>
 
@@ -42,6 +43,7 @@
 #include <libfiemap/image_manager.h>
 #include <openssl/sha.h>
 #include <private/android_filesystem_config.h>
+#include <storage_literals/storage_literals.h>
 
 #include "file_paths.h"
 #include "libgsi_private.h"
@@ -52,6 +54,7 @@ namespace gsi {
 using namespace std::literals;
 using namespace android::fs_mgr;
 using namespace android::fiemap;
+using namespace android::storage_literals;
 using android::base::ReadFileToString;
 using android::base::ReadFullyAtOffset;
 using android::base::RemoveFileIfExists;
@@ -493,6 +496,27 @@ binder::Status GsiService::getAvbPublicKey(AvbPublicKey* dst, int32_t* _aidl_ret
     return binder::Status::ok();
 }
 
+binder::Status GsiService::suggestScratchSize(int64_t* _aidl_return) {
+    ENFORCE_SYSTEM;
+
+    static constexpr int64_t kMinScratchSize = 512_MiB;
+    static constexpr int64_t kMaxScratchSize = 2_GiB;
+
+    int64_t size = 0;
+    struct statvfs info;
+    if (statvfs(install_dir_.c_str(), &info)) {
+        PLOG(ERROR) << "Could not statvfs(" << install_dir_ << ")";
+    } else {
+        const int64_t available_space = static_cast<int64_t>(info.f_bavail) * info.f_frsize;
+        LOG(INFO) << "Available space of " << install_dir_ << ": " << available_space;
+        // Use up to half of free space. Don't exhaust the storage device with scratch partition.
+        size = available_space / 2;
+    }
+
+    *_aidl_return = std::clamp(size, kMinScratchSize, kMaxScratchSize);
+    return binder::Status::ok();
+}
+
 bool GsiService::CreateInstallStatusFile() {
     if (!android::base::WriteStringToFile("0", kDsuInstallStatusFile)) {
         PLOG(ERROR) << "write " << kDsuInstallStatusFile;
diff --git a/gsi_service.h b/gsi_service.h
index 3f81786..c9e4e05 100644
--- a/gsi_service.h
+++ b/gsi_service.h
@@ -68,6 +68,7 @@ class GsiService : public BinderService<GsiService>, public BnGsiService {
                                     android::sp<IImageService>* _aidl_return) override;
     binder::Status dumpDeviceMapperDevices(std::string* _aidl_return) override;
     binder::Status getAvbPublicKey(AvbPublicKey* dst, int32_t* _aidl_return) override;
+    binder::Status suggestScratchSize(int64_t* _aidl_return) override;
 
     // This is in GsiService, rather than GsiInstaller, since we need to access
     // it outside of the main lock which protects the unique_ptr.