libsnapshot:Snapuserd: IO path support with dm-snapshot target (2c6c0bff) · Commits · e / os / android_system_core

fs_mgr/libsnapshot/Android.bp

+35 −2

Original line number	Diff line number	Diff line
		@@ -148,12 +148,12 @@ cc_library_static {
		recovery_available: true,
		shared_libs: [
		"libbase",
		"libcrypto",
		"liblog",
		],
		static_libs: [
		"libz",
		],
		ramdisk_available: true,
		}

		cc_library_static {
		@@ -347,6 +347,9 @@ cc_test {

		cc_defaults {
		name: "snapuserd_defaults",
		defaults: [
		"fs_mgr_defaults",
		],
		srcs: [
		"snapuserd.cpp",
		],
		@@ -360,6 +363,8 @@ cc_defaults {
		"libbase",
		"liblog",
		"libdm",
		"libz",
		"libsnapshot_cow",
		],
		}

		@@ -375,7 +380,6 @@ cc_binary {

		ramdisk: true,
		static_executable: true,
		system_shared_libs: [],
		}

		cc_test {
		@@ -473,3 +477,32 @@ cc_binary {
		},
		},
		}

		cc_test {
		name: "cow_snapuserd_test",
		defaults: [
		"fs_mgr_defaults",
		],
		srcs: [
		"cow_snapuserd_test.cpp",
		],
		cflags: [
		"-Wall",
		"-Werror",
		],
		shared_libs: [
		"libbase",
		"liblog",
		"libz",
		],
		static_libs: [
		"libgtest",
		"libsnapshot_cow",
		],
		header_libs: [
		"libstorage_literals_headers",
		],
		test_min_api_level: 30,
		auto_gen_config: true,
		require_root: false,
		}

fs_mgr/libsnapshot/cow_reader.cpp

+24 −2

Original line number	Diff line number	Diff line
		@@ -20,7 +20,6 @@
		#include <android-base/file.h>
		#include <android-base/logging.h>
		#include <libsnapshot/cow_reader.h>
		#include <openssl/sha.h>
		#include <zlib.h>

		namespace android {
		@@ -28,11 +27,13 @@ namespace snapshot {

		CowReader::CowReader() : fd_(-1), header_(), fd_size_(0) {}

		static void SHA256(const void* data, size_t length, uint8_t out[32]) {
		static void SHA256(const void*, size_t, uint8_t[]) {
		#if 0
		SHA256_CTX c;
		SHA256_Init(&c);
		SHA256_Update(&c, data, length);
		SHA256_Final(out, &c);
		#endif
		}

		bool CowReader::Parse(android::base::unique_fd&& fd) {
		@@ -69,16 +70,35 @@ bool CowReader::Parse(android::base::borrowed_fd fd) {
		return false;
		}

		if (header_.magic != kCowMagicNumber) {
		LOG(ERROR) << "Header Magic corrupted. Magic: " << header_.magic
		<< "Expected: " << kCowMagicNumber;
		return false;
		}

		if ((header_.major_version != kCowVersionMajor) \|\|
		(header_.minor_version != kCowVersionMinor)) {
		LOG(ERROR) << "Header version mismatch";
		LOG(ERROR) << "Major version: " << header_.major_version
		<< "Expected: " << kCowVersionMajor;
		LOG(ERROR) << "Minor version: " << header_.minor_version
		<< "Expected: " << kCowVersionMinor;
		return false;
		}

		uint8_t header_csum[32];
		{
		CowHeader tmp = header_;
		memset(&tmp.header_checksum, 0, sizeof(tmp.header_checksum));
		memset(header_csum, 0, sizeof(uint8_t) * 32);

		SHA256(&tmp, sizeof(tmp), header_csum);
		}
		if (memcmp(header_csum, header_.header_checksum, sizeof(header_csum)) != 0) {
		LOG(ERROR) << "header checksum is invalid";
		return false;
		}

		return true;
		}

		@@ -140,6 +160,8 @@ std::unique_ptr<ICowOpIter> CowReader::GetOpIter() {
		}

		uint8_t csum[32];
		memset(csum, 0, sizeof(uint8_t) * 32);

		SHA256(ops_buffer.get(), header_.ops_size, csum);
		if (memcmp(csum, header_.ops_checksum, sizeof(csum)) != 0) {
		LOG(ERROR) << "ops checksum does not match";

fs_mgr/libsnapshot/cow_snapuserd_test.cpp

0 → 100644

+255 −0

Original line number	Diff line number	Diff line
		// Copyright (C) 2018 The Android Open Source Project
		//
		// Licensed under the Apache License, Version 2.0 (the "License");
		// you may not use this file except in compliance with the License.
		// You may obtain a copy of the License at
		//
		// http://www.apache.org/licenses/LICENSE-2.0
		//
		// Unless required by applicable law or agreed to in writing, software
		// distributed under the License is distributed on an "AS IS" BASIS,
		// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		// See the License for the specific language governing permissions and
		// limitations under the License.

		#include <fcntl.h>
		#include <linux/fs.h>
		#include <sys/ioctl.h>
		#include <sys/stat.h>
		#include <sys/types.h>

		#include <iostream>
		#include <memory>
		#include <string_view>

		#include <android-base/file.h>
		#include <android-base/unique_fd.h>
		#include <gtest/gtest.h>
		#include <libsnapshot/cow_writer.h>
		#include <storage_literals/storage_literals.h>

		namespace android {
		namespace snapshot {

		using namespace android::storage_literals;
		using android::base::unique_fd;

		class SnapuserdTest : public ::testing::Test {
		protected:
		void SetUp() override {
		cow_ = std::make_unique<TemporaryFile>();
		ASSERT_GE(cow_->fd, 0) << strerror(errno);
		}

		void TearDown() override { cow_ = nullptr; }

		std::unique_ptr<TemporaryFile> cow_;
		};

		TEST_F(SnapuserdTest, ReadWrite) {
		loff_t offset = 0;
		size_t size = 100_MiB;
		unique_fd rnd_fd;
		unique_fd sys_fd;
		unique_fd snapshot_fd;
		unique_fd system_a_fd;
		std::string cmd;

		rnd_fd.reset(open("/dev/random", O_RDONLY));
		ASSERT_TRUE(rnd_fd > 0);

		std::unique_ptr<uint8_t[]> random_buffer_1;
		std::unique_ptr<uint8_t[]> random_buffer_2;
		std::unique_ptr<uint8_t[]> system_buffer;

		random_buffer_1 = std::make_unique<uint8_t[]>(size);

		random_buffer_2 = std::make_unique<uint8_t[]>(size);

		system_buffer = std::make_unique<uint8_t[]>(size);

		// Fill random data
		for (size_t j = 0; j < (size / 1_MiB); j++) {
		ASSERT_EQ(ReadFullyAtOffset(rnd_fd, (char*)random_buffer_1.get() + offset, 1_MiB, 0), true);

		ASSERT_EQ(ReadFullyAtOffset(rnd_fd, (char*)random_buffer_2.get() + offset, 1_MiB, 0), true);

		offset += 1_MiB;
		}

		sys_fd.reset(open("/dev/block/mapper/system_a", O_RDONLY));
		ASSERT_TRUE(sys_fd > 0);

		// Read from system partition from offset 0 of size 100MB
		ASSERT_EQ(ReadFullyAtOffset(sys_fd, system_buffer.get(), size, 0), true);

		//================Create a COW file with the following operations===========
		//
		// Create COW file which is gz compressed
		//
		// 0-100 MB of replace operation with random data
		// 100-200 MB of copy operation
		// 200-300 MB of zero operation
		// 300-400 MB of replace operation with random data

		CowOptions options;
		options.compression = "gz";
		CowWriter writer(options);

		ASSERT_TRUE(writer.Initialize(cow_->fd));

		// Write 100MB random data to COW file which is gz compressed from block 0
		ASSERT_TRUE(writer.AddRawBlocks(0, random_buffer_1.get(), size));

		size_t num_blocks = size / options.block_size;
		size_t blk_start_copy = num_blocks;
		size_t blk_end_copy = blk_start_copy + num_blocks;
		size_t source_blk = 0;

		// Copy blocks - source_blk starts from 0 as snapuserd
		// has to read from block 0 in system_a partition
		//
		// This initializes copy operation from block 0 of size 100 MB from
		// /dev/block/mapper/system_a
		for (size_t i = blk_start_copy; i < blk_end_copy; i++) {
		ASSERT_TRUE(writer.AddCopy(i, source_blk));
		source_blk += 1;
		}

		size_t blk_zero_copy_start = blk_end_copy;
		size_t blk_zero_copy_end = blk_zero_copy_start + num_blocks;

		// 100 MB filled with zeroes
		ASSERT_TRUE(writer.AddZeroBlocks(blk_zero_copy_start, num_blocks));

		// Final 100MB filled with random data which is gz compressed
		size_t blk_random2_replace_start = blk_zero_copy_end;

		ASSERT_TRUE(writer.AddRawBlocks(blk_random2_replace_start, random_buffer_2.get(), size));

		// Flush operations
		ASSERT_TRUE(writer.Finalize());

		ASSERT_EQ(lseek(cow_->fd, 0, SEEK_SET), 0);

		//================Setup dm-snapshot and start snapuserd daemon===========

		// Create a COW device. Number of sectors is chosen random which can
		// hold at least 400MB of data

		system_a_fd.reset(open("/dev/block/mapper/system_a", O_RDONLY));
		ASSERT_TRUE(system_a_fd > 0);

		int blksize;
		int err = ioctl(system_a_fd.get(), BLKGETSIZE, &blksize);
		if (err < 0) {
		ASSERT_TRUE(0);
		}

		cmd = "dmctl create system_cow user 0 " + std::to_string(blksize);
		system(cmd.c_str());

		// Start the snapuserd daemon
		if (fork() == 0) {
		const char* argv[] = {"/system/bin/snapuserd", cow_->path, "/dev/block/mapper/system_a",
		nullptr};
		if (execv(argv[0], const_cast<char**>(argv))) {
		ASSERT_TRUE(0);
		}
		}

		cmd.clear();

		cmd = "dmctl create system-snapshot -ro snapshot 0 " + std::to_string(blksize);
		cmd += " /dev/block/mapper/system_a /dev/block/mapper/system_cow ";
		cmd += "P 8";
		system(cmd.c_str());

		// Wait so that snapshot device is created
		sleep(5);
		std::unique_ptr<uint8_t[]> snapuserd_buffer = std::make_unique<uint8_t[]>(size);

		offset = 0;

		snapshot_fd.reset(open("/dev/block/mapper/system-snapshot", O_RDONLY));
		ASSERT_TRUE(snapshot_fd > 0);

		//================Start IO operation on dm-snapshot device=================
		// This will test the following paths:
		//
		// 1: IO path for all three operations and interleaving of operations.
		// 2: Merging of blocks in kernel during metadata read
		// 3: Bulk IO issued by kernel duing merge operation

		// Read from snapshot device of size 100MB from offset 0. This tests the
		// 1st replace operation.
		//
		// IO path:
		//
		// dm-snap->dm-snap-persistent->dm-user->snapuserd->read_compressed_cow (replace
		// op)->decompress_cow->return

		ASSERT_EQ(ReadFullyAtOffset(snapshot_fd, snapuserd_buffer.get(), size, offset), true);

		// Update the offset
		offset += size;

		// Compare data with random_buffer_1.
		ASSERT_EQ(memcmp(snapuserd_buffer.get(), random_buffer_1.get(), size), 0);

		// Clear the buffer
		memset(snapuserd_buffer.get(), 0, size);

		// Read from snapshot device of size 100MB from offset 100MB. This tests the
		// copy operation.
		//
		// IO path:
		//
		// dm-snap->dm-snap-persistent->dm-user->snapuserd->read_from_system_a_partition
		// (copy op) -> return
		ASSERT_EQ(ReadFullyAtOffset(snapshot_fd, snapuserd_buffer.get(), size, offset), true);

		// Update the offset
		offset += size;

		// Compare data with system_buffer.
		ASSERT_EQ(memcmp(snapuserd_buffer.get(), system_buffer.get(), size), 0);

		// Read from snapshot device of size 100MB from offset 200MB. This tests the
		// zero operation.
		//
		// IO path:
		//
		// dm-snap->dm-snap-persistent->dm-user->snapuserd->fill_memory_with_zero
		// (zero op) -> return
		ASSERT_EQ(ReadFullyAtOffset(snapshot_fd, snapuserd_buffer.get(), size, offset), true);

		// Fill the random_buffer_1 with zero as we no longer need it
		memset(random_buffer_1.get(), 0, size);

		// Compare data with zero filled buffer
		ASSERT_EQ(memcmp(snapuserd_buffer.get(), random_buffer_1.get(), size), 0);

		// Update the offset
		offset += size;

		// Read from snapshot device of size 100MB from offset 300MB. This tests the
		// final replace operation.
		//
		// IO path:
		//
		// dm-snap->dm-snap-persistent->dm-user->snapuserd->read_compressed_cow (replace
		// op)->decompress_cow->return
		ASSERT_EQ(ReadFullyAtOffset(snapshot_fd, snapuserd_buffer.get(), size, offset), true);

		// Compare data with random_buffer_2.
		ASSERT_EQ(memcmp(snapuserd_buffer.get(), random_buffer_2.get(), size), 0);
		}

		} // namespace snapshot
		} // namespace android

		int main(int argc, char** argv) {
		::testing::InitGoogleTest(&argc, argv);
		return RUN_ALL_TESTS();
		}

fs_mgr/libsnapshot/cow_writer.cpp

+8 −2

Original line number	Diff line number	Diff line
		@@ -23,7 +23,6 @@
		#include <android-base/logging.h>
		#include <android-base/unique_fd.h>
		#include <libsnapshot/cow_writer.h>
		#include <openssl/sha.h>
		#include <zlib.h>

		namespace android {
		@@ -179,11 +178,15 @@ std::basic_string<uint8_t> CowWriter::Compress(const void* data, size_t length)
		return {};
		}

		static void SHA256(const void* data, size_t length, uint8_t out[32]) {
		// TODO: Fix compilation issues when linking libcrypto library
		// when snapuserd is compiled as part of ramdisk.
		static void SHA256(const void*, size_t, uint8_t[]) {
		#if 0
		SHA256_CTX c;
		SHA256_Init(&c);
		SHA256_Update(&c, data, length);
		SHA256_Final(out, &c);
		#endif
		}

		bool CowWriter::Finalize() {
		@@ -199,6 +202,9 @@ bool CowWriter::Finalize() {
		header_.ops_offset = offs;
		header_.ops_size = ops_.size();

		memset(header_.ops_checksum, 0, sizeof(uint8_t) * 32);
		memset(header_.header_checksum, 0, sizeof(uint8_t) * 32);

		SHA256(ops_.data(), ops_.size(), header_.ops_checksum);
		SHA256(&header_, sizeof(header_), header_.header_checksum);

fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h

+4 −0

Original line number	Diff line number	Diff line
		@@ -92,6 +92,10 @@ class CowReader : public ICowReader {
		bool Parse(android::base::borrowed_fd fd);

		bool GetHeader(CowHeader* header) override;

		// Create a CowOpIter object which contains header_.num_ops
		// CowOperation objects. Get() returns a unique CowOperation object
		// whose lifeteime depends on the CowOpIter object
		std::unique_ptr<ICowOpIter> GetOpIter() override;
		bool GetRawBytes(uint64_t offset, void* buffer, size_t len) override;
		bool ReadData(const CowOperation& op, IByteSink* sink) override;