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Commit 2ba8eea4 authored by Akilesh Kailash's avatar Akilesh Kailash
Browse files

snapuserd: Sort REPLACE ops for batch merge 



Since we will be iterating forward for user-space
merge, we need to sort the blocks in increasing order
so that blocks can be batch merged if contiguous.

For dm-snapshot merging, we will continue to sort
in decreasing order.

Bug: 193863397
Test: Snapuserd_test
Signed-off-by: default avatarAkilesh Kailash <akailash@google.com>
Change-Id: I25fb5fce054f716a2ad0dddc0d0c3afef18bc7ad
parent b94353ca

fs_mgr/libsnapshot/cow_reader.cpp

+17 −4
Original line number Diff line number Diff line
@@ -34,11 +34,12 @@ 
namespace android {

namespace snapshot {



CowReader::CowReader()

CowReader::CowReader(ReaderFlags reader_flag)

    : fd_(-1),

      header_(),

      fd_size_(0),

      merge_op_blocks_(std::make_shared<std::vector<uint32_t>>()) {}

      merge_op_blocks_(std::make_shared<std::vector<uint32_t>>()),

      reader_flag_(reader_flag) {}



static void SHA256(const void*, size_t, uint8_t[]) {

#if 0
@@ -415,7 +416,7 @@ bool CowReader::ParseOps(std::optional<uint64_t> label) { 
//==============================================================

bool CowReader::PrepMergeOps() {

    auto merge_op_blocks = std::make_shared<std::vector<uint32_t>>();

    std::set<int, std::greater<int>> other_ops;

    std::vector<int> other_ops;

    auto seq_ops_set = std::unordered_set<uint32_t>();

    auto block_map = std::make_shared<std::unordered_map<uint32_t, int>>();

    size_t num_seqs = 0;
@@ -446,7 +447,7 @@ bool CowReader::PrepMergeOps() { 
        if (!has_seq_ops_ && IsOrderedOp(current_op)) {

            merge_op_blocks->emplace_back(current_op.new_block);

        } else if (seq_ops_set.count(current_op.new_block) == 0) {

            other_ops.insert(current_op.new_block);

            other_ops.push_back(current_op.new_block);

        }

        block_map->insert({current_op.new_block, i});

    }
@@ -462,6 +463,18 @@ bool CowReader::PrepMergeOps() { 
    } else {

        num_ordered_ops_to_merge_ = 0;

    }



    // Sort the vector in increasing order if merging in user-space as

    // we can batch merge them when iterating from forward.

    //

    // dm-snapshot-merge requires decreasing order as we iterate the blocks

    // in reverse order.

    if (reader_flag_ == ReaderFlags::USERSPACE_MERGE) {

        std::sort(other_ops.begin(), other_ops.end());

    } else {

        std::sort(other_ops.begin(), other_ops.end(), std::greater<int>());

    }



    merge_op_blocks->reserve(merge_op_blocks->size() + other_ops.size());

    for (auto block : other_ops) {

        merge_op_blocks->emplace_back(block);

fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h

+7 −1
Original line number Diff line number Diff line
@@ -104,7 +104,12 @@ class ICowOpIter { 


class CowReader final : public ICowReader {

  public:

    CowReader();

    enum class ReaderFlags {

        DEFAULT = 0,

        USERSPACE_MERGE = 1,

    };



    CowReader(ReaderFlags reader_flag = ReaderFlags::DEFAULT);

    ~CowReader() { owned_fd_ = {}; }



    // Parse the COW, optionally, up to the given label. If no label is
@@ -166,6 +171,7 @@ class CowReader final : public ICowReader { 
    uint64_t num_ordered_ops_to_merge_;

    bool has_seq_ops_;

    std::shared_ptr<std::unordered_map<uint64_t, uint64_t>> data_loc_;

    ReaderFlags reader_flag_;

};



}  // namespace snapshot

fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_core.cpp

+1 −1
Original line number Diff line number Diff line
@@ -139,7 +139,7 @@ void SnapshotHandler::CheckMergeCompletionStatus() { 
}



bool SnapshotHandler::ReadMetadata() {

    reader_ = std::make_unique<CowReader>();

    reader_ = std::make_unique<CowReader>(CowReader::ReaderFlags::USERSPACE_MERGE);

    CowHeader header;

    CowOptions options;