Merge "libsnapshot: Communicate compression status to update_engine."

fs_mgr/libsnapshot/android/snapshot/snapshot.proto

@@ -156,7 +156,7 @@ message SnapshotUpdateStatus {
     MergePhase merge_phase = 6;
 }
 
-// Next: 4
+// Next: 5
 message SnapshotMergeReport {
     // Status of the update after the merge attempts.
     UpdateState state = 1;
@@ -167,4 +167,7 @@ message SnapshotMergeReport {
 
     // Total size of all the COW images before the update.
     uint64 cow_file_size = 3;
+
+    // Whether compression/dm-user was used for any snapshots.
+    bool compression_enabled = 4;
 }

fs_mgr/libsnapshot/include/libsnapshot/mock_snapshot.h

@@ -32,6 +32,7 @@ class MockSnapshotManager : public ISnapshotManager {
                 (const std::function<bool()>& callback, const std::function<bool()>& before_cancel),
                 (override));
     MOCK_METHOD(UpdateState, GetUpdateState, (double* progress), (override));
+    MOCK_METHOD(bool, UpdateUsesCompression, (), (override));
     MOCK_METHOD(Return, CreateUpdateSnapshots,
                 (const chromeos_update_engine::DeltaArchiveManifest& manifest), (override));
     MOCK_METHOD(bool, MapUpdateSnapshot,

fs_mgr/libsnapshot/include/libsnapshot/snapshot.h

@@ -170,6 +170,10 @@ class ISnapshotManager {
     //   Other: 0
     virtual UpdateState GetUpdateState(double* progress = nullptr) = 0;
 
+    // Returns true if compression is enabled for the current update. This always returns false if
+    // UpdateState is None, or no snapshots have been created.
+    virtual bool UpdateUsesCompression() = 0;
+
     // Create necessary COW device / files for OTA clients. New logical partitions will be added to
     // group "cow" in target_metadata. Regions of partitions of current_metadata will be
     // "write-protected" and snapshotted.
@@ -326,6 +330,7 @@ class SnapshotManager final : public ISnapshotManager {
     UpdateState ProcessUpdateState(const std::function<bool()>& callback = {},
                                    const std::function<bool()>& before_cancel = {}) override;
     UpdateState GetUpdateState(double* progress = nullptr) override;
+    bool UpdateUsesCompression() override;
     Return CreateUpdateSnapshots(const DeltaArchiveManifest& manifest) override;
     bool MapUpdateSnapshot(const CreateLogicalPartitionParams& params,
                            std::string* snapshot_path) override;
@@ -720,6 +725,9 @@ class SnapshotManager final : public ISnapshotManager {
 
     SnapuserdClient* snapuserd_client() const { return snapuserd_client_.get(); }
 
+    // Helper of UpdateUsesCompression
+    bool UpdateUsesCompression(LockedFile* lock);
+
     std::string gsid_dir_;
     std::string metadata_dir_;
     std::unique_ptr<IDeviceInfo> device_;

fs_mgr/libsnapshot/include/libsnapshot/snapshot_stats.h

@@ -28,7 +28,7 @@ class ISnapshotMergeStats {
     virtual ~ISnapshotMergeStats() = default;
     // Called when merge starts or resumes.
     virtual bool Start() = 0;
-    virtual void set_state(android::snapshot::UpdateState state) = 0;
+    virtual void set_state(android::snapshot::UpdateState state, bool using_compression) = 0;
     virtual void set_cow_file_size(uint64_t cow_file_size) = 0;
     virtual uint64_t cow_file_size() = 0;
 
@@ -51,7 +51,7 @@ class SnapshotMergeStats : public ISnapshotMergeStats {
 
     // ISnapshotMergeStats overrides
     bool Start() override;
-    void set_state(android::snapshot::UpdateState state) override;
+    void set_state(android::snapshot::UpdateState state, bool using_compression) override;
     void set_cow_file_size(uint64_t cow_file_size) override;
     uint64_t cow_file_size() override;
     std::unique_ptr<Result> Finish() override;

fs_mgr/libsnapshot/include/libsnapshot/snapshot_stub.h

@@ -32,6 +32,7 @@ class SnapshotManagerStub : public ISnapshotManager {
     UpdateState ProcessUpdateState(const std::function<bool()>& callback = {},
                                    const std::function<bool()>& before_cancel = {}) override;
     UpdateState GetUpdateState(double* progress = nullptr) override;
+    bool UpdateUsesCompression() override;
     Return CreateUpdateSnapshots(
             const chromeos_update_engine::DeltaArchiveManifest& manifest) override;
     bool MapUpdateSnapshot(const android::fs_mgr::CreateLogicalPartitionParams& params,

fs_mgr/libsnapshot/snapshot.cpp

@@ -1683,6 +1683,17 @@ UpdateState SnapshotManager::GetUpdateState(double* progress) {
     return state;
 }
 
+bool SnapshotManager::UpdateUsesCompression() {
+    auto lock = LockShared();
+    if (!lock) return false;
+    return UpdateUsesCompression(lock.get());
+}
+
+bool SnapshotManager::UpdateUsesCompression(LockedFile* lock) {
+    SnapshotUpdateStatus update_status = ReadSnapshotUpdateStatus(lock);
+    return update_status.compression_enabled();
+}
+
 bool SnapshotManager::ListSnapshots(LockedFile* lock, std::vector<std::string>* snapshots) {
     CHECK(lock);
 
@@ -2109,7 +2120,7 @@ bool SnapshotManager::UnmapCowDevices(LockedFile* lock, const std::string& name)
 
     auto& dm = DeviceMapper::Instance();
 
-    if (IsCompressionEnabled() && !UnmapDmUserDevice(name)) {
+    if (UpdateUsesCompression(lock) && !UnmapDmUserDevice(name)) {
         return false;
     }
 

fs_mgr/libsnapshot/snapshot_stats.cpp

@@ -84,8 +84,9 @@ bool SnapshotMergeStats::Start() {
     return WriteState();
 }
 
-void SnapshotMergeStats::set_state(android::snapshot::UpdateState state) {
+void SnapshotMergeStats::set_state(android::snapshot::UpdateState state, bool using_compression) {
     report_.set_state(state);
+    report_.set_compression_enabled(using_compression);
 }
 
 void SnapshotMergeStats::set_cow_file_size(uint64_t cow_file_size) {

fs_mgr/libsnapshot/snapshot_stub.cpp

@@ -116,9 +116,14 @@ std::unique_ptr<AutoDevice> SnapshotManagerStub::EnsureMetadataMounted() {
     return nullptr;
 }
 
+bool SnapshotManagerStub::UpdateUsesCompression() {
+    LOG(ERROR) << __FUNCTION__ << " should never be called.";
+    return false;
+}
+
 class SnapshotMergeStatsStub : public ISnapshotMergeStats {
     bool Start() override { return false; }
-    void set_state(android::snapshot::UpdateState) override {}
+    void set_state(android::snapshot::UpdateState, bool) override {}
     void set_cow_file_size(uint64_t) override {}
     uint64_t cow_file_size() override { return 0; }
     std::unique_ptr<Result> Finish() override { return nullptr; }