Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 83127b73 authored by Daniel Rosenberg's avatar Daniel Rosenberg
Browse files

libsnapshot: Add Sequence Ops 

This adds the ability to write sequence ops. A Sequence op is a list of
block values in the new image. These ops may have dependencies on data
that is overwritten by future ops, so must be merged in a specific
order, regardless of their order in the cow file.

This patch only introduces the operation. The following patches will
actually make use of it.

Bug: 177104308
Test: Builds
Change-Id: I9162b49e5061079416ac9e5661c8b1245298044b
parent 5e2363e1

fs_mgr/libsnapshot/cow_format.cpp

+3 −0
Original line number Diff line number Diff line
@@ -37,6 +37,8 @@ std::ostream& operator<<(std::ostream& os, CowOperation const& op) { 
        os << "kCowLabelOp,   ";

    else if (op.type == kCowClusterOp)

        os << "kCowClusterOp  ";

    else if (op.type == kCowSequenceOp)

        os << "kCowSequenceOp ";

    else if (op.type == kCowFooterOp)

        os << "kCowFooterOp  ";

    else
@@ -81,6 +83,7 @@ bool IsMetadataOp(const CowOperation& op) { 
        case kCowLabelOp:

        case kCowClusterOp:

        case kCowFooterOp:

        case kCowSequenceOp:

            return true;

        default:

            return false;

fs_mgr/libsnapshot/cow_reader.cpp

+2 −0
Original line number Diff line number Diff line
@@ -201,6 +201,8 @@ bool CowReader::ParseOps(std::optional<uint64_t> label) { 
                current_op_num--;

                done = true;

                break;

            } else if (current_op.type == kCowSequenceOp) {

                has_seq_ops_ = true;

            }

        }

fs_mgr/libsnapshot/cow_writer.cpp

+22 −3
Original line number Diff line number Diff line
@@ -76,9 +76,8 @@ bool ICowWriter::AddLabel(uint64_t label) { 
    return EmitLabel(label);

}



bool ICowWriter::AddSequenceData(size_t /*num_ops*/, const uint32_t* /*data*/) {

    LOG(ERROR) << "AddSequenceData not yet implemented";

    return false;

bool ICowWriter::AddSequenceData(size_t num_ops, const uint32_t* data) {

    return EmitSequenceData(num_ops, data);

}



bool ICowWriter::ValidateNewBlock(uint64_t new_block) {
@@ -337,6 +336,26 @@ bool CowWriter::EmitLabel(uint64_t label) { 
    return WriteOperation(op) && Sync();

}



bool CowWriter::EmitSequenceData(size_t num_ops, const uint32_t* data) {

    CHECK(!merge_in_progress_);

    size_t to_add = 0;

    size_t max_ops = std::numeric_limits<uint16_t>::max() / sizeof(uint32_t);

    while (num_ops > 0) {

        CowOperation op = {};

        op.type = kCowSequenceOp;

        op.source = next_data_pos_;

        to_add = std::min(num_ops, max_ops);

        op.data_length = static_cast<uint16_t>(to_add * sizeof(uint32_t));

        if (!WriteOperation(op, data, op.data_length)) {

            PLOG(ERROR) << "AddSequenceData: write failed";

            return false;

        }

        num_ops -= to_add;

        data += to_add;

    }

    return true;

}



bool CowWriter::EmitCluster() {

    CowOperation op = {};

    op.type = kCowClusterOp;

fs_mgr/libsnapshot/include/libsnapshot/cow_format.h

+1 −0
Original line number Diff line number Diff line
@@ -148,6 +148,7 @@ static constexpr uint8_t kCowReplaceOp = 2; 
static constexpr uint8_t kCowZeroOp = 3;

static constexpr uint8_t kCowLabelOp = 4;

static constexpr uint8_t kCowClusterOp = 5;

static constexpr uint8_t kCowSequenceOp = 7;

static constexpr uint8_t kCowFooterOp = -1;



static constexpr uint8_t kCowCompressNone = 0;

fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h

+1 −0
Original line number Diff line number Diff line
@@ -165,6 +165,7 @@ class CowReader : public ICowReader { 
    std::shared_ptr<std::vector<CowOperation>> ops_;

    uint64_t total_data_ops_;

    uint64_t copy_ops_;

    bool has_seq_ops_;

};



}  // namespace snapshot