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Commit cbc204b3 authored by David Anderson's avatar David Anderson
Browse files

libsnapshot: Use the compression algorithm specified in the DeltaArchiveManifest. 

update_engine and libsnapshot must agree on CowOptions parameters,
otherwise the COW size estimation may be incorrect.

Bug: N/A
Test: vts_libsnapshot_test
      apply OTA, snapshotctl dump
Change-Id: I219ae458dfa19e4b3c96360d3b847edb2a01ebc8
parent e8867021

fs_mgr/libsnapshot/android/snapshot/snapshot.proto

+4 −1
Original line number Diff line number Diff line
@@ -46,7 +46,7 @@ enum MergePhase { 
    SECOND_PHASE = 2;

}



// Next: 11

// Next: 12

message SnapshotStatus {

    // Name of the snapshot. This is usually the name of the snapshotted

    // logical partition; for example, "system_b".
@@ -102,6 +102,9 @@ message SnapshotStatus { 


    // The old partition size (if none existed, this will be zero).

    uint64 old_partition_size = 10;



    // Compression algorithm (none, gz, or brotli).

    string compression_algorithm = 11;

}



// Next: 8

fs_mgr/libsnapshot/partition_cow_creator.h

+1 −0
Original line number Diff line number Diff line
@@ -58,6 +58,7 @@ struct PartitionCowCreator { 
    std::vector<ChromeOSExtent> extra_extents = {};

    // True if compression is enabled.

    bool compression_enabled = false;

    std::string compression_algorithm;



    struct Return {

        SnapshotStatus snapshot_status;

fs_mgr/libsnapshot/snapshot.cpp

+19 −5
Original line number Diff line number Diff line
@@ -359,6 +359,7 @@ bool SnapshotManager::CreateSnapshot(LockedFile* lock, PartitionCowCreator* cow_ 
    status->set_sectors_allocated(0);

    status->set_metadata_sectors(0);

    status->set_compression_enabled(cow_creator->compression_enabled);

    status->set_compression_algorithm(cow_creator->compression_algorithm);



    if (!WriteSnapshotStatus(lock, *status)) {

        PLOG(ERROR) << "Could not write snapshot status: " << status->name();
@@ -2660,9 +2661,20 @@ Return SnapshotManager::CreateUpdateSnapshots(const DeltaArchiveManifest& manife 
    // these devices.

    AutoDeviceList created_devices;



    bool use_compression = IsCompressionEnabled() &&

                           manifest.dynamic_partition_metadata().vabc_enabled() &&

                           !device_->IsRecovery();

    const auto& dap_metadata = manifest.dynamic_partition_metadata();

    bool use_compression =

            IsCompressionEnabled() && dap_metadata.vabc_enabled() && !device_->IsRecovery();



    std::string compression_algorithm;

    if (use_compression) {

        compression_algorithm = dap_metadata.vabc_compression_param();

        if (compression_algorithm.empty()) {

            // Older OTAs don't set an explicit compression type, so default to gz.

            compression_algorithm = "gz";

        }

    } else {

        compression_algorithm = "none";

    }



    PartitionCowCreator cow_creator{

            .target_metadata = target_metadata.get(),
@@ -2673,6 +2685,7 @@ Return SnapshotManager::CreateUpdateSnapshots(const DeltaArchiveManifest& manife 
            .update = nullptr,

            .extra_extents = {},

            .compression_enabled = use_compression,

            .compression_algorithm = compression_algorithm,

    };



    auto ret = CreateUpdateSnapshotsInternal(lock.get(), manifest, &cow_creator, &created_devices,
@@ -2917,7 +2930,7 @@ Return SnapshotManager::InitializeUpdateSnapshots( 
                return Return::Error();

            }



            CowWriter writer(CowOptions{});

            CowWriter writer(CowOptions{.compression = it->second.compression_algorithm()});

            if (!writer.Initialize(fd) || !writer.Finalize()) {

                LOG(ERROR) << "Could not initialize COW device for " << target_partition->name();

                return Return::Error();
@@ -3024,7 +3037,7 @@ std::unique_ptr<ISnapshotWriter> SnapshotManager::OpenCompressedSnapshotWriter( 
    CHECK(lock);



    CowOptions cow_options;

    cow_options.compression = "gz";

    cow_options.compression = status.compression_algorithm();

    cow_options.max_blocks = {status.device_size() / cow_options.block_size};



    // Currently we don't support partial snapshots, since partition_cow_creator
@@ -3163,6 +3176,7 @@ bool SnapshotManager::Dump(std::ostream& os) { 
        ss << "    cow file size (bytes): " << status.cow_file_size() << std::endl;

        ss << "    allocated sectors: " << status.sectors_allocated() << std::endl;

        ss << "    metadata sectors: " << status.metadata_sectors() << std::endl;

        ss << "    compression: " << status.compression_algorithm() << std::endl;

    }

    os << ss.rdbuf();

    return ok;

fs_mgr/libsnapshot/snapshot_test.cpp

+11 −0
Original line number Diff line number Diff line
@@ -423,6 +423,11 @@ TEST_F(SnapshotTest, CreateSnapshot) { 


    PartitionCowCreator cow_creator;

    cow_creator.compression_enabled = IsCompressionEnabled();

    if (cow_creator.compression_enabled) {

        cow_creator.compression_algorithm = "gz";

    } else {

        cow_creator.compression_algorithm = "none";

    }



    static const uint64_t kDeviceSize = 1024 * 1024;

    SnapshotStatus status;
@@ -446,6 +451,7 @@ TEST_F(SnapshotTest, CreateSnapshot) { 
        ASSERT_EQ(status.device_size(), kDeviceSize);

        ASSERT_EQ(status.snapshot_size(), kDeviceSize);

        ASSERT_EQ(status.compression_enabled(), cow_creator.compression_enabled);

        ASSERT_EQ(status.compression_algorithm(), cow_creator.compression_algorithm);

    }



    ASSERT_TRUE(sm->UnmapSnapshot(lock_.get(), "test-snapshot"));
@@ -576,6 +582,11 @@ TEST_F(SnapshotTest, FirstStageMountAndMerge) { 
    SnapshotStatus status;

    ASSERT_TRUE(init->ReadSnapshotStatus(lock_.get(), "test_partition_b", &status));

    ASSERT_EQ(status.state(), SnapshotState::CREATED);

    if (IsCompressionEnabled()) {

        ASSERT_EQ(status.compression_algorithm(), "gz");

    } else {

        ASSERT_EQ(status.compression_algorithm(), "none");

    }



    DeviceMapper::TargetInfo target;

    ASSERT_TRUE(init->IsSnapshotDevice("test_partition_b", &target));

fs_mgr/libsnapshot/update_engine/update_metadata.proto

+1 −0
Original line number Diff line number Diff line
@@ -74,6 +74,7 @@ message DynamicPartitionGroup { 
message DynamicPartitionMetadata {

    repeated DynamicPartitionGroup groups = 1;

    optional bool vabc_enabled = 3;

    optional string vabc_compression_param = 4;

}



message DeltaArchiveManifest {