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Commit 7cd1c031 authored by Akilesh Kailash's avatar Akilesh Kailash Committed by Gerrit Code Review
Browse files

Merge "libsnapshot:snapuserd: Batch merge copy operation"

parents 08938393 66914e2b

fs_mgr/libsnapshot/Android.bp

+1 −0
Original line number Diff line number Diff line
@@ -549,6 +549,7 @@ cc_test { 
    ],

    srcs: [

        "cow_snapuserd_test.cpp",

        "snapuserd.cpp",

    ],

    cflags: [

        "-Wall",

fs_mgr/libsnapshot/cow_reader.cpp

+6 −8
Original line number Diff line number Diff line
@@ -181,6 +181,7 @@ bool CowReader::ParseOps(std::optional<uint64_t> label) { 
        ops_buffer->resize(current_op_num);

    }



    LOG(DEBUG) << "COW file read complete. Total ops: " << ops_buffer->size();

    // To successfully parse a COW file, we need either:

    //  (1) a label to read up to, and for that label to be found, or

    //  (2) a valid footer.
@@ -298,10 +299,9 @@ void CowReader::InitializeMerge() { 
    // are contiguous. These are monotonically increasing numbers.

    //

    // When both (1) and (2) are true, kernel will batch merge the operations.

    // However, we do not want copy operations to be batch merged as

    // a crash or system reboot during an overlapping copy can drive the device

    // to a corrupted state. Hence, merging of copy operations should always be

    // done as a individual 4k block. In the above case, since the

    // In the above case, we have to ensure that the copy operations

    // are merged first before replace operations are done. Hence,

    // we will not change the order of copy operations. Since,

    // cow_op->new_block numbers are contiguous, we will ensure that the

    // cow block numbers assigned in ReadMetadata() for these respective copy

    // operations are not contiguous forcing kernel to issue merge for each
@@ -328,10 +328,8 @@ void CowReader::InitializeMerge() { 
    //

    // Merge sequence will look like:

    //

    // Merge-1 - Copy-op-1

    // Merge-2 - Copy-op-2

    // Merge-3 - Copy-op-3

    // Merge-4 - Batch-merge {Replace-op-7, Replace-op-6, Zero-op-8,

    // Merge-1 - Batch-merge { Copy-op-1, Copy-op-2, Copy-op-3 }

    // Merge-2 - Batch-merge {Replace-op-7, Replace-op-6, Zero-op-8,

    //                        Replace-op-4, Zero-op-9, Replace-op-5 }

    //==============================================================

fs_mgr/libsnapshot/cow_snapuserd_test.cpp

+299 −8
Original line number Diff line number Diff line
@@ -36,6 +36,8 @@ 
#include <libsnapshot/snapuserd_client.h>

#include <storage_literals/storage_literals.h>



#include "snapuserd.h"



namespace android {

namespace snapshot {
@@ -119,7 +121,6 @@ class CowSnapuserdTest final { 
    void CreateDmUserDevice();

    void StartSnapuserdDaemon();

    void CreateSnapshotDevice();

    unique_fd CreateTempFile(const std::string& name, size_t size);



    unique_ptr<LoopDevice> base_loop_;

    unique_ptr<TempDevice> dmuser_dev_;
@@ -140,7 +141,24 @@ class CowSnapuserdTest final { 
    int total_base_size_;

};



unique_fd CowSnapuserdTest::CreateTempFile(const std::string& name, size_t size) {

class CowSnapuserdMetadataTest final {

  public:

    void Setup();

    void SetupPartialArea();

    void ValidateMetadata();

    void ValidatePartialFilledArea();



  private:

    void InitMetadata();

    void CreateCowDevice();

    void CreateCowPartialFilledArea();



    std::unique_ptr<Snapuserd> snapuserd_;

    std::unique_ptr<TemporaryFile> cow_system_;

    size_t size_ = 1_MiB;

};



static unique_fd CreateTempFile(const std::string& name, size_t size) {

    unique_fd fd(syscall(__NR_memfd_create, name.c_str(), MFD_ALLOW_SEALING));

    if (fd < 0) {

        return {};
@@ -430,25 +448,299 @@ void CowSnapuserdTest::SimulateDaemonRestart() { 
}



void CowSnapuserdTest::MergeInterrupt() {

    // Interrupt merge at various intervals

    StartMerge();

    std::this_thread::sleep_for(250ms);

    SimulateDaemonRestart();



    StartMerge();

    std::this_thread::sleep_for(250ms);

    SimulateDaemonRestart();



    StartMerge();

    std::this_thread::sleep_for(4s);

    std::this_thread::sleep_for(150ms);

    SimulateDaemonRestart();



    StartMerge();

    std::this_thread::sleep_for(3s);

    std::this_thread::sleep_for(100ms);

    SimulateDaemonRestart();



    StartMerge();

    std::this_thread::sleep_for(3s);

    std::this_thread::sleep_for(800ms);

    SimulateDaemonRestart();



    StartMerge();

    std::this_thread::sleep_for(1s);

    std::this_thread::sleep_for(600ms);

    SimulateDaemonRestart();



    ASSERT_TRUE(Merge());

}



void CowSnapuserdMetadataTest::CreateCowPartialFilledArea() {

    std::string path = android::base::GetExecutableDirectory();

    cow_system_ = std::make_unique<TemporaryFile>(path);



    CowOptions options;

    options.compression = "gz";

    CowWriter writer(options);



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



    // Area 0 is completely filled with 256 exceptions

    for (int i = 0; i < 256; i++) {

        ASSERT_TRUE(writer.AddCopy(i, 256 + i));

    }



    // Area 1 is partially filled with 2 copy ops and 10 zero ops

    ASSERT_TRUE(writer.AddCopy(500, 1000));

    ASSERT_TRUE(writer.AddCopy(501, 1001));



    ASSERT_TRUE(writer.AddZeroBlocks(300, 10));



    // Flush operations

    ASSERT_TRUE(writer.Finalize());

}



void CowSnapuserdMetadataTest::ValidatePartialFilledArea() {

    int area_sz = snapuserd_->GetMetadataAreaSize();



    ASSERT_EQ(area_sz, 2);



    size_t new_chunk = 263;

    // Verify the partially filled area

    void* buffer = snapuserd_->GetExceptionBuffer(1);

    loff_t offset = 0;

    struct disk_exception* de;

    for (int i = 0; i < 12; i++) {

        de = reinterpret_cast<struct disk_exception*>((char*)buffer + offset);

        ASSERT_EQ(de->old_chunk, i);

        ASSERT_EQ(de->new_chunk, new_chunk);

        offset += sizeof(struct disk_exception);

        new_chunk += 1;

    }



    de = reinterpret_cast<struct disk_exception*>((char*)buffer + offset);

    ASSERT_EQ(de->old_chunk, 0);

    ASSERT_EQ(de->new_chunk, 0);

}



void CowSnapuserdMetadataTest::SetupPartialArea() {

    CreateCowPartialFilledArea();

    InitMetadata();

}



void CowSnapuserdMetadataTest::CreateCowDevice() {

    unique_fd rnd_fd;

    loff_t offset = 0;



    std::string path = android::base::GetExecutableDirectory();

    cow_system_ = std::make_unique<TemporaryFile>(path);



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

    ASSERT_TRUE(rnd_fd > 0);



    std::unique_ptr<uint8_t[]> random_buffer_1_ = 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);



        offset += 1_MiB;

    }



    CowOptions options;

    options.compression = "gz";

    CowWriter writer(options);



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



    size_t num_blocks = size_ / options.block_size;



    // Overlapping region. This has to be split

    // into two batch operations

    ASSERT_TRUE(writer.AddCopy(23, 20));

    ASSERT_TRUE(writer.AddCopy(22, 19));

    ASSERT_TRUE(writer.AddCopy(21, 18));

    ASSERT_TRUE(writer.AddCopy(20, 17));

    ASSERT_TRUE(writer.AddCopy(19, 16));

    ASSERT_TRUE(writer.AddCopy(18, 15));



    // Contiguous region but blocks in ascending order

    // Daemon has to ensure that these blocks are merged

    // in a batch

    ASSERT_TRUE(writer.AddCopy(50, 75));

    ASSERT_TRUE(writer.AddCopy(51, 76));

    ASSERT_TRUE(writer.AddCopy(52, 77));

    ASSERT_TRUE(writer.AddCopy(53, 78));



    // Dis-contiguous region

    ASSERT_TRUE(writer.AddCopy(110, 130));

    ASSERT_TRUE(writer.AddCopy(105, 125));

    ASSERT_TRUE(writer.AddCopy(100, 120));



    // Overlap

    ASSERT_TRUE(writer.AddCopy(25, 30));

    ASSERT_TRUE(writer.AddCopy(30, 31));



    size_t source_blk = num_blocks;



    ASSERT_TRUE(writer.AddRawBlocks(source_blk, random_buffer_1_.get(), size_));



    size_t blk_zero_copy_start = source_blk + num_blocks;



    ASSERT_TRUE(writer.AddZeroBlocks(blk_zero_copy_start, num_blocks));



    // Flush operations

    ASSERT_TRUE(writer.Finalize());

}



void CowSnapuserdMetadataTest::InitMetadata() {

    snapuserd_ = std::make_unique<Snapuserd>("", cow_system_->path, "");

    ASSERT_TRUE(snapuserd_->InitCowDevice());

}



void CowSnapuserdMetadataTest::Setup() {

    CreateCowDevice();

    InitMetadata();

}



void CowSnapuserdMetadataTest::ValidateMetadata() {

    int area_sz = snapuserd_->GetMetadataAreaSize();

    ASSERT_EQ(area_sz, 3);



    size_t old_chunk;

    size_t new_chunk;



    for (int i = 0; i < area_sz; i++) {

        void* buffer = snapuserd_->GetExceptionBuffer(i);

        loff_t offset = 0;

        if (i == 0) {

            old_chunk = 256;

            new_chunk = 2;

        } else if (i == 1) {

            old_chunk = 512;

            new_chunk = 259;

        }

        for (int j = 0; j < 256; j++) {

            struct disk_exception* de =

                    reinterpret_cast<struct disk_exception*>((char*)buffer + offset);



            if (i != 2) {

                ASSERT_EQ(de->old_chunk, old_chunk);

                ASSERT_EQ(de->new_chunk, new_chunk);

                old_chunk += 1;

                new_chunk += 1;

            } else {

                break;

            }

            offset += sizeof(struct disk_exception);

        }



        if (i == 2) {

            // The first 5 copy operation is not batch merged

            // as the sequence is discontiguous

            struct disk_exception* de =

                    reinterpret_cast<struct disk_exception*>((char*)buffer + offset);

            ASSERT_EQ(de->old_chunk, 30);

            ASSERT_EQ(de->new_chunk, 518);

            offset += sizeof(struct disk_exception);



            de = reinterpret_cast<struct disk_exception*>((char*)buffer + offset);

            ASSERT_EQ(de->old_chunk, 25);

            ASSERT_EQ(de->new_chunk, 520);

            offset += sizeof(struct disk_exception);



            de = reinterpret_cast<struct disk_exception*>((char*)buffer + offset);

            ASSERT_EQ(de->old_chunk, 100);

            ASSERT_EQ(de->new_chunk, 522);

            offset += sizeof(struct disk_exception);



            de = reinterpret_cast<struct disk_exception*>((char*)buffer + offset);

            ASSERT_EQ(de->old_chunk, 105);

            ASSERT_EQ(de->new_chunk, 524);

            offset += sizeof(struct disk_exception);



            de = reinterpret_cast<struct disk_exception*>((char*)buffer + offset);

            ASSERT_EQ(de->old_chunk, 110);

            ASSERT_EQ(de->new_chunk, 526);

            offset += sizeof(struct disk_exception);



            // The next 4 operations are batch merged as

            // both old and new chunk are contiguous

            de = reinterpret_cast<struct disk_exception*>((char*)buffer + offset);

            ASSERT_EQ(de->old_chunk, 50);

            ASSERT_EQ(de->new_chunk, 528);

            offset += sizeof(struct disk_exception);



            de = reinterpret_cast<struct disk_exception*>((char*)buffer + offset);

            ASSERT_EQ(de->old_chunk, 51);

            ASSERT_EQ(de->new_chunk, 529);

            offset += sizeof(struct disk_exception);



            de = reinterpret_cast<struct disk_exception*>((char*)buffer + offset);

            ASSERT_EQ(de->old_chunk, 52);

            ASSERT_EQ(de->new_chunk, 530);

            offset += sizeof(struct disk_exception);



            de = reinterpret_cast<struct disk_exception*>((char*)buffer + offset);

            ASSERT_EQ(de->old_chunk, 53);

            ASSERT_EQ(de->new_chunk, 531);

            offset += sizeof(struct disk_exception);



            // This is handling overlap operation with

            // two batch merge operations.

            de = reinterpret_cast<struct disk_exception*>((char*)buffer + offset);

            ASSERT_EQ(de->old_chunk, 18);

            ASSERT_EQ(de->new_chunk, 533);

            offset += sizeof(struct disk_exception);



            de = reinterpret_cast<struct disk_exception*>((char*)buffer + offset);

            ASSERT_EQ(de->old_chunk, 19);

            ASSERT_EQ(de->new_chunk, 534);

            offset += sizeof(struct disk_exception);



            de = reinterpret_cast<struct disk_exception*>((char*)buffer + offset);

            ASSERT_EQ(de->old_chunk, 20);

            ASSERT_EQ(de->new_chunk, 535);

            offset += sizeof(struct disk_exception);



            de = reinterpret_cast<struct disk_exception*>((char*)buffer + offset);

            ASSERT_EQ(de->old_chunk, 21);

            ASSERT_EQ(de->new_chunk, 537);

            offset += sizeof(struct disk_exception);



            de = reinterpret_cast<struct disk_exception*>((char*)buffer + offset);

            ASSERT_EQ(de->old_chunk, 22);

            ASSERT_EQ(de->new_chunk, 538);

            offset += sizeof(struct disk_exception);



            de = reinterpret_cast<struct disk_exception*>((char*)buffer + offset);

            ASSERT_EQ(de->old_chunk, 23);

            ASSERT_EQ(de->new_chunk, 539);

            offset += sizeof(struct disk_exception);



            // End of metadata

            de = reinterpret_cast<struct disk_exception*>((char*)buffer + offset);

            ASSERT_EQ(de->old_chunk, 0);

            ASSERT_EQ(de->new_chunk, 0);

            offset += sizeof(struct disk_exception);

        }

    }

}



TEST(Snapuserd_Test, Snapshot_Metadata) {

    CowSnapuserdMetadataTest harness;

    harness.Setup();

    harness.ValidateMetadata();

}



TEST(Snapuserd_Test, Snapshot_Metadata_Overlap) {

    CowSnapuserdMetadataTest harness;

    harness.SetupPartialArea();

    harness.ValidatePartialFilledArea();

}



TEST(Snapuserd_Test, Snapshot_Merge_Resume) {

    CowSnapuserdTest harness;

    ASSERT_TRUE(harness.Setup());
@@ -457,7 +749,7 @@ TEST(Snapuserd_Test, Snapshot_Merge_Resume) { 
    harness.Shutdown();

}



TEST(Snapuserd_Test, Snapshot) {

TEST(Snapuserd_Test, Snapshot_IO_TEST) {

    CowSnapuserdTest harness;

    ASSERT_TRUE(harness.Setup());

    harness.ReadSnapshotDeviceAndValidate();
@@ -465,7 +757,6 @@ TEST(Snapuserd_Test, Snapshot) { 
    harness.ValidateMerge();

    harness.Shutdown();

}



}  // namespace snapshot

}  // namespace android

fs_mgr/libsnapshot/cow_writer.cpp

+2 −6
Original line number Diff line number Diff line
@@ -491,7 +491,7 @@ bool CowWriter::Sync() { 
    return true;

}



bool CowWriter::CommitMerge(int merged_ops, bool sync) {

bool CowWriter::CommitMerge(int merged_ops) {

    CHECK(merge_in_progress_);

    header_.num_merge_ops += merged_ops;
@@ -506,12 +506,8 @@ bool CowWriter::CommitMerge(int merged_ops, bool sync) { 
        return false;

    }



    // Sync only for merging of copy operations.

    if (sync) {

    return Sync();

}

    return true;

}



bool CowWriter::Truncate(off_t length) {

    if (is_dev_null_ || is_block_device_) {

fs_mgr/libsnapshot/include/libsnapshot/cow_writer.h

+1 −1
Original line number Diff line number Diff line
@@ -101,7 +101,7 @@ class CowWriter : public ICowWriter { 
    bool InitializeAppend(android::base::borrowed_fd fd, uint64_t label);



    void InitializeMerge(android::base::borrowed_fd fd, CowHeader* header);

    bool CommitMerge(int merged_ops, bool sync);

    bool CommitMerge(int merged_ops);



    bool Finalize() override;