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Commit 59ce7a45 authored by Daniel Zheng's avatar Daniel Zheng
Browse files

libsnapshot: update offset functions 

Since these functions are used across both parser and writer, updating
it as inline functions in cow_format.

Test: cow_api_test
Change-Id: I9824684e3b9b48947accce935335d4019d745ae0
parent 32006975

fs_mgr/libsnapshot/include/libsnapshot/cow_format.h

+13 −0
Original line number Diff line number Diff line
@@ -232,6 +232,19 @@ static inline uint64_t GetCowOpSourceInfoData(const CowOperation& op) { 
    return op.source_info & kCowOpSourceInfoDataMask;

}



static constexpr off_t GetOpOffset(uint32_t op_index, const CowHeaderV3 header) {

    return header.prefix.header_size + header.buffer_size +

           (header.resume_point_max * sizeof(ResumePoint)) + (op_index * sizeof(CowOperationV3));

}

static constexpr off_t GetDataOffset(const CowHeaderV3 header) {

    return header.prefix.header_size + header.buffer_size +

           (header.resume_point_max * sizeof(ResumePoint)) +

           header.op_count_max * sizeof(CowOperation);

}

static constexpr off_t GetResumeOffset(const CowHeaderV3 header) {

    return header.prefix.header_size + header.buffer_size;

}



struct CowFooter {

    CowFooterOperation op;

    uint8_t unused[64];

fs_mgr/libsnapshot/libsnapshot_cow/parser_v3.cpp

+3 −9
Original line number Diff line number Diff line
@@ -94,18 +94,12 @@ std::optional<uint32_t> CowParserV3::FindResumeOp(const uint64_t label) { 
    return std::nullopt;

}



off_t CowParserV3::GetDataOffset() const {

    return sizeof(CowHeaderV3) + header_.buffer_size +

           header_.resume_point_max * sizeof(ResumePoint) +

           header_.op_count_max * sizeof(CowOperation);

}



bool CowParserV3::ParseOps(borrowed_fd fd, const uint32_t op_index) {

    ops_ = std::make_shared<std::vector<CowOperationV3>>();

    ops_->resize(op_index);



    const off_t offset = header_.prefix.header_size + header_.buffer_size +

                         header_.resume_point_max * sizeof(ResumePoint);

    // read beginning of operation buffer -> so op_index = 0

    const off_t offset = GetOpOffset(0, header_);

    if (!android::base::ReadFullyAtOffset(fd, ops_->data(), ops_->size() * sizeof(CowOperationV3),

                                          offset)) {

        PLOG(ERROR) << "read ops failed";
@@ -113,7 +107,7 @@ bool CowParserV3::ParseOps(borrowed_fd fd, const uint32_t op_index) { 
    }



    // fill out mapping of XOR op data location

    uint64_t data_pos = GetDataOffset();

    uint64_t data_pos = GetDataOffset(header_);



    xor_data_loc_ = std::make_shared<std::unordered_map<uint64_t, uint64_t>>();

fs_mgr/libsnapshot/libsnapshot_cow/parser_v3.h

+0 −1
Original line number Diff line number Diff line
@@ -50,7 +50,6 @@ class CowParserV3 final : public CowParserBase { 
  private:

    bool ParseOps(android::base::borrowed_fd fd, const uint32_t op_index);

    std::optional<uint32_t> FindResumeOp(const uint64_t label);

    off_t GetDataOffset() const;

    CowHeaderV3 header_ = {};

    std::shared_ptr<std::vector<CowOperationV3>> ops_;

    bool ReadResumeBuffer(android::base::borrowed_fd fd);

fs_mgr/libsnapshot/libsnapshot_cow/writer_v3.cpp

+4 −4
Original line number Diff line number Diff line
@@ -170,7 +170,7 @@ bool CowWriterV3::OpenForWrite() { 
        LOG(ERROR) << "Header sync failed";

        return false;

    }

    next_data_pos_ = GetDataOffset();

    next_data_pos_ = GetDataOffset(header_);

    return true;

}
@@ -192,7 +192,7 @@ bool CowWriterV3::OpenForAppend(uint64_t label) { 


    resume_points_ = parser.resume_points();

    options_.block_size = header_.block_size;

    next_data_pos_ = GetDataOffset();

    next_data_pos_ = GetDataOffset(header_);



    TranslatedCowOps ops;

    parser.Translate(&ops);
@@ -307,7 +307,7 @@ bool CowWriterV3::EmitLabel(uint64_t label) { 


    if (!android::base::WriteFullyAtOffset(fd_, resume_points_->data(),

                                           resume_points_->size() * sizeof(ResumePoint),

                                           GetResumeOffset())) {

                                           GetResumeOffset(header_))) {

        PLOG(ERROR) << "writing resume buffer failed";

        return false;

    }
@@ -333,7 +333,7 @@ bool CowWriterV3::WriteOperation(const CowOperationV3& op, const void* data, siz 
        return false;

    }



    const off_t offset = GetOpOffset(header_.op_count);

    const off_t offset = GetOpOffset(header_.op_count, header_);

    if (!android::base::WriteFullyAtOffset(fd_, &op, sizeof(op), offset)) {

        PLOG(ERROR) << "write failed for " << op << " at " << offset;

        return false;

fs_mgr/libsnapshot/libsnapshot_cow/writer_v3.h

+0 −13
Original line number Diff line number Diff line
@@ -49,19 +49,6 @@ class CowWriterV3 : public CowWriterBase { 
                    uint16_t offset, uint8_t type);

    bool CompressBlocks(size_t num_blocks, const void* data);



    off_t GetOpOffset(uint32_t op_index) const {

        CHECK_LT(op_index, header_.op_count_max);

        return header_.prefix.header_size + header_.buffer_size +

               (header_.resume_point_max * sizeof(ResumePoint)) +

               (op_index * sizeof(CowOperationV3));

    }

    off_t GetDataOffset() const {

        return sizeof(CowHeaderV3) + header_.buffer_size +

               (header_.resume_point_max * sizeof(ResumePoint)) +

               header_.op_count_max * sizeof(CowOperation);

    }

    off_t GetResumeOffset() const { return sizeof(CowHeaderV3) + header_.buffer_size; }



  private:

    CowHeaderV3 header_{};

    CowCompression compression_;