Merge "libsnapshot: Implement OpenSnapshotWriter for compressed snapshots." am: 862b01746e (e1bb91b3) · Commits · e / os / android_system_core

fs_mgr/libsnapshot/Android.bp

+12 −0

Original line number	Diff line number	Diff line
		@@ -28,6 +28,7 @@ cc_defaults {
		"liblog",
		],
		static_libs: [
		"libbrotli",
		"libdm",
		"libfstab",
		"libsnapshot_cow",
		@@ -109,6 +110,9 @@ cc_library_static {
		defaults: ["libsnapshot_defaults"],
		srcs: [":libsnapshot_sources"],
		recovery_available: true,
		cflags: [
		"-DLIBSNAPSHOT_NO_COW_WRITE",
		],
		static_libs: [
		"libfs_mgr",
		],
		@@ -122,6 +126,9 @@ cc_library_static {
		],
		srcs: [":libsnapshot_sources"],
		recovery_available: true,
		cflags: [
		"-DLIBSNAPSHOT_NO_COW_WRITE",
		],
		static_libs: [
		"libfs_mgr",
		],
		@@ -244,6 +251,7 @@ cc_defaults {
		static_libs: [
		"android.hardware.boot@1.0",
		"android.hardware.boot@1.1",
		"libbrotli",
		"libfs_mgr",
		"libgsi",
		"libgmock",
		@@ -276,9 +284,11 @@ cc_binary {
		"snapshotctl.cpp",
		],
		static_libs: [
		"libbrotli",
		"libfstab",
		"libsnapshot",
		"libsnapshot_cow",
		"libz",
		"update_metadata-protos",
		],
		shared_libs: [
		@@ -332,6 +342,7 @@ cc_defaults {
		],
		static_libs: [
		"libbase",
		"libbrotli",
		"libcrypto_static",
		"libcutils",
		"libext2_uuid",
		@@ -345,6 +356,7 @@ cc_defaults {
		"libsnapshot_cow",
		"libsnapshot_test_helpers",
		"libprotobuf-mutator",
		"libz",
		],
		header_libs: [
		"libchrome",

fs_mgr/libsnapshot/include/libsnapshot/snapshot.h

+5 −2

Original line number	Diff line number	Diff line
		@@ -532,8 +532,8 @@ class SnapshotManager final : public ISnapshotManager {
		// Target/base device (eg system_b), always present.
		std::string target_device;

		// COW path (eg system_cow). Not present if no COW is needed.
		std::string cow_device;
		// COW name (eg system_cow). Not present if no COW is needed.
		std::string cow_device_name;

		// dm-snapshot instance. Not present in Update mode for VABC.
		std::string snapshot_device;
		@@ -626,6 +626,9 @@ class SnapshotManager final : public ISnapshotManager {
		bool GetMappedImageDeviceStringOrPath(const std::string& device_name,
		std::string* device_string_or_mapped_path);

		// Same as above, but for paths only (no major:minor device strings).
		bool GetMappedImageDevicePath(const std::string& device_name, std::string* device_path);

		std::string gsid_dir_;
		std::string metadata_dir_;
		std::unique_ptr<IDeviceInfo> device_;

fs_mgr/libsnapshot/include/libsnapshot/snapshot_writer.h

+24 −1

Original line number	Diff line number	Diff line
		@@ -42,6 +42,29 @@ class ISnapshotWriter : public ICowWriter {
		android::base::unique_fd source_fd_;
		};

		// Send writes to a COW or a raw device directly, based on a threshold.
		class CompressedSnapshotWriter : public ISnapshotWriter {
		public:
		CompressedSnapshotWriter(const CowOptions& options);

		// Sets the COW device, if needed.
		bool SetCowDevice(android::base::unique_fd&& cow_device);

		bool Flush() override;
		uint64_t GetCowSize() override;
		std::unique_ptr<FileDescriptor> OpenReader() override;

		protected:
		bool EmitCopy(uint64_t new_block, uint64_t old_block) override;
		bool EmitRawBlocks(uint64_t new_block_start, const void* data, size_t size) override;
		bool EmitZeroBlocks(uint64_t new_block_start, uint64_t num_blocks) override;

		private:
		android::base::unique_fd cow_device_;

		std::unique_ptr<CowWriter> cow_;
		};

		// Write directly to a dm-snapshot device.
		class OnlineKernelSnapshotWriter : public ISnapshotWriter {
		public:
		@@ -52,7 +75,7 @@ class OnlineKernelSnapshotWriter : public ISnapshotWriter {

		bool Flush() override;
		uint64_t GetCowSize() override { return cow_size_; }
		virtual std::unique_ptr<FileDescriptor> OpenReader() override;
		std::unique_ptr<FileDescriptor> OpenReader() override;

		protected:
		bool EmitRawBlocks(uint64_t new_block_start, const void* data, size_t size) override;

fs_mgr/libsnapshot/snapshot.cpp

+67 −6

Original line number	Diff line number	Diff line
		@@ -271,7 +271,7 @@ bool SnapshotManager::FinishedSnapshotWrites(bool wipe) {
		return false;
		}

		if (!EnsureNoOverflowSnapshot(lock.get())) {
		if (!IsCompressionEnabled() && !EnsureNoOverflowSnapshot(lock.get())) {
		LOG(ERROR) << "Cannot ensure there are no overflow snapshots.";
		return false;
		}
		@@ -1716,7 +1716,7 @@ bool SnapshotManager::MapPartitionWithSnapshot(LockedFile* lock,
		return false;
		}
		if (paths) {
		paths->cow_device = cow_device;
		paths->cow_device_name = cow_name;
		}

		remaining_time = GetRemainingTime(params.timeout_ms, begin);
		@@ -1724,6 +1724,7 @@ bool SnapshotManager::MapPartitionWithSnapshot(LockedFile* lock,

		if (context == SnapshotContext::Update && IsCompressionEnabled()) {
		// Stop here, we can't run dm-user yet, the COW isn't built.
		created_devices.Release();
		return true;
		}

		@@ -2471,6 +2472,12 @@ bool SnapshotManager::MapUpdateSnapshot(const CreateLogicalPartitionParams& para

		std::unique_ptr<ISnapshotWriter> SnapshotManager::OpenSnapshotWriter(
		const android::fs_mgr::CreateLogicalPartitionParams& params) {
		#if defined(LIBSNAPSHOT_NO_COW_WRITE)
		(void)params;

		LOG(ERROR) << "Snapshots cannot be written in first-stage init or recovery";
		return nullptr;
		#else
		// First unmap any existing mapping.
		auto lock = LockShared();
		if (!lock) return nullptr;
		@@ -2486,7 +2493,7 @@ std::unique_ptr<ISnapshotWriter> SnapshotManager::OpenSnapshotWriter(
		}

		SnapshotStatus status;
		if (!paths.cow_device.empty()) {
		if (!paths.cow_device_name.empty()) {
		if (!ReadSnapshotStatus(lock.get(), params.GetPartitionName(), &status)) {
		return nullptr;
		}
		@@ -2504,14 +2511,51 @@ std::unique_ptr<ISnapshotWriter> SnapshotManager::OpenSnapshotWriter(
		return OpenCompressedSnapshotWriter(lock.get(), params.GetPartitionName(), status, paths);
		}
		return OpenKernelSnapshotWriter(lock.get(), params.GetPartitionName(), status, paths);
		#endif
		}

		#if !defined(LIBSNAPSHOT_NO_COW_WRITE)
		std::unique_ptr<ISnapshotWriter> SnapshotManager::OpenCompressedSnapshotWriter(
		LockedFile*, const std::string&, const SnapshotStatus&, const SnapshotPaths&) {
		LOG(ERROR) << "OpenSnapshotWriter not yet implemented for compression";
		LockedFile* lock, [[maybe_unused]] const std::string& partition_name,
		const SnapshotStatus& status, const SnapshotPaths& paths) {
		CHECK(lock);

		CowOptions cow_options;
		cow_options.compression = "gz";
		cow_options.max_blocks = {status.device_size() / cow_options.block_size};

		// Currently we don't support partial snapshots, since partition_cow_creator
		// never creates this scenario.
		CHECK(status.snapshot_size() == status.device_size());

		auto writer = std::make_unique<CompressedSnapshotWriter>(cow_options);

		unique_fd base_fd(open(paths.target_device.c_str(), O_RDWR \| O_CLOEXEC));
		if (base_fd < 0) {
		PLOG(ERROR) << "OpenCompressedSnapshotWriter: open " << paths.target_device;
		return nullptr;
		}
		writer->SetSourceDevice(std::move(base_fd));

		std::string cow_path;
		if (!GetMappedImageDevicePath(paths.cow_device_name, &cow_path)) {
		LOG(ERROR) << "Could not determine path for " << paths.cow_device_name;
		return nullptr;
		}

		unique_fd cow_fd(open(cow_path.c_str(), O_RDWR \| O_CLOEXEC));
		if (cow_fd < 0) {
		PLOG(ERROR) << "OpenCompressedSnapshotWriter: open " << cow_path;
		return nullptr;
		}
		if (!writer->SetCowDevice(std::move(cow_fd))) {
		LOG(ERROR) << "Could not create COW writer from " << cow_path;
		return nullptr;
		}

		return writer;
		}

		std::unique_ptr<ISnapshotWriter> SnapshotManager::OpenKernelSnapshotWriter(
		LockedFile* lock, [[maybe_unused]] const std::string& partition_name,
		const SnapshotStatus& status, const SnapshotPaths& paths) {
		@@ -2534,6 +2578,7 @@ std::unique_ptr<ISnapshotWriter> SnapshotManager::OpenKernelSnapshotWriter(

		return writer;
		}
		#endif // !defined(LIBSNAPSHOT_NO_COW_WRITE)

		bool SnapshotManager::UnmapUpdateSnapshot(const std::string& target_partition_name) {
		auto lock = LockShared();
		@@ -2872,6 +2917,22 @@ ISnapshotMergeStats* SnapshotManager::GetSnapshotMergeStatsInstance() {
		return SnapshotMergeStats::GetInstance(*this);
		}

		// This is only to be used in recovery or normal Android (not first-stage init).
		// We don't guarantee dm paths are available in first-stage init, because ueventd
		// isn't running yet.
		bool SnapshotManager::GetMappedImageDevicePath(const std::string& device_name,
		std::string* device_path) {
		auto& dm = DeviceMapper::Instance();

		// Try getting the device string if it is a device mapper device.
		if (dm.GetState(device_name) != DmDeviceState::INVALID) {
		return dm.GetDmDevicePathByName(device_name, device_path);
		}

		// Otherwise, get path from IImageManager.
		return images_->GetMappedImageDevice(device_name, device_path);
		}

		bool SnapshotManager::GetMappedImageDeviceStringOrPath(const std::string& device_name,
		std::string* device_string_or_mapped_path) {
		auto& dm = DeviceMapper::Instance();

fs_mgr/libsnapshot/snapshot_writer.cpp

+34 −0

Original line number	Diff line number	Diff line
		@@ -33,6 +33,40 @@ void ISnapshotWriter::SetSourceDevice(android::base::unique_fd&& source_fd) {
		source_fd_ = std::move(source_fd);
		}

		CompressedSnapshotWriter::CompressedSnapshotWriter(const CowOptions& options)
		: ISnapshotWriter(options) {}

		bool CompressedSnapshotWriter::SetCowDevice(android::base::unique_fd&& cow_device) {
		cow_device_ = std::move(cow_device);
		cow_ = std::make_unique<CowWriter>(options_);

		return cow_->Initialize(cow_device_);
		}
		bool CompressedSnapshotWriter::Flush() {
		return cow_->Flush();
		}

		uint64_t CompressedSnapshotWriter::GetCowSize() {
		return cow_->GetCowSize();
		}

		std::unique_ptr<FileDescriptor> CompressedSnapshotWriter::OpenReader() {
		return nullptr;
		}

		bool CompressedSnapshotWriter::EmitCopy(uint64_t new_block, uint64_t old_block) {
		return cow_->AddCopy(new_block, old_block);
		}

		bool CompressedSnapshotWriter::EmitRawBlocks(uint64_t new_block_start, const void* data,
		size_t size) {
		return cow_->AddRawBlocks(new_block_start, data, size);
		}

		bool CompressedSnapshotWriter::EmitZeroBlocks(uint64_t new_block_start, uint64_t num_blocks) {
		return cow_->AddZeroBlocks(new_block_start, num_blocks);
		}

		OnlineKernelSnapshotWriter::OnlineKernelSnapshotWriter(const CowOptions& options)
		: ISnapshotWriter(options) {}