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Diffstat (limited to 'src/index/blockfilterindex.cpp')
-rw-r--r-- | src/index/blockfilterindex.cpp | 467 |
1 files changed, 467 insertions, 0 deletions
diff --git a/src/index/blockfilterindex.cpp b/src/index/blockfilterindex.cpp new file mode 100644 index 0000000000..20f33baf2c --- /dev/null +++ b/src/index/blockfilterindex.cpp @@ -0,0 +1,467 @@ +// Copyright (c) 2018 The Bitcoin Core developers +// Distributed under the MIT software license, see the accompanying +// file COPYING or http://www.opensource.org/licenses/mit-license.php. + +#include <map> + +#include <dbwrapper.h> +#include <index/blockfilterindex.h> +#include <util/system.h> +#include <validation.h> + +/* The index database stores three items for each block: the disk location of the encoded filter, + * its dSHA256 hash, and the header. Those belonging to blocks on the active chain are indexed by + * height, and those belonging to blocks that have been reorganized out of the active chain are + * indexed by block hash. This ensures that filter data for any block that becomes part of the + * active chain can always be retrieved, alleviating timing concerns. + * + * The filters themselves are stored in flat files and referenced by the LevelDB entries. This + * minimizes the amount of data written to LevelDB and keeps the database values constant size. The + * disk location of the next block filter to be written (represented as a FlatFilePos) is stored + * under the DB_FILTER_POS key. + * + * Keys for the height index have the type [DB_BLOCK_HEIGHT, uint32 (BE)]. The height is represented + * as big-endian so that sequential reads of filters by height are fast. + * Keys for the hash index have the type [DB_BLOCK_HASH, uint256]. + */ +constexpr char DB_BLOCK_HASH = 's'; +constexpr char DB_BLOCK_HEIGHT = 't'; +constexpr char DB_FILTER_POS = 'P'; + +constexpr unsigned int MAX_FLTR_FILE_SIZE = 0x1000000; // 16 MiB +/** The pre-allocation chunk size for fltr?????.dat files */ +constexpr unsigned int FLTR_FILE_CHUNK_SIZE = 0x100000; // 1 MiB + +namespace { + +struct DBVal { + uint256 hash; + uint256 header; + FlatFilePos pos; + + ADD_SERIALIZE_METHODS; + + template <typename Stream, typename Operation> + inline void SerializationOp(Stream& s, Operation ser_action) { + READWRITE(hash); + READWRITE(header); + READWRITE(pos); + } +}; + +struct DBHeightKey { + int height; + + DBHeightKey() : height(0) {} + DBHeightKey(int height_in) : height(height_in) {} + + template<typename Stream> + void Serialize(Stream& s) const + { + ser_writedata8(s, DB_BLOCK_HEIGHT); + ser_writedata32be(s, height); + } + + template<typename Stream> + void Unserialize(Stream& s) + { + char prefix = ser_readdata8(s); + if (prefix != DB_BLOCK_HEIGHT) { + throw std::ios_base::failure("Invalid format for block filter index DB height key"); + } + height = ser_readdata32be(s); + } +}; + +struct DBHashKey { + uint256 hash; + + DBHashKey(const uint256& hash_in) : hash(hash_in) {} + + ADD_SERIALIZE_METHODS; + + template <typename Stream, typename Operation> + inline void SerializationOp(Stream& s, Operation ser_action) { + char prefix = DB_BLOCK_HASH; + READWRITE(prefix); + if (prefix != DB_BLOCK_HASH) { + throw std::ios_base::failure("Invalid format for block filter index DB hash key"); + } + + READWRITE(hash); + } +}; + +}; // namespace + +static std::map<BlockFilterType, BlockFilterIndex> g_filter_indexes; + +BlockFilterIndex::BlockFilterIndex(BlockFilterType filter_type, + size_t n_cache_size, bool f_memory, bool f_wipe) + : m_filter_type(filter_type) +{ + const std::string& filter_name = BlockFilterTypeName(filter_type); + if (filter_name.empty()) throw std::invalid_argument("unknown filter_type"); + + fs::path path = GetDataDir() / "indexes" / "blockfilter" / filter_name; + fs::create_directories(path); + + m_name = filter_name + " block filter index"; + m_db = MakeUnique<BaseIndex::DB>(path / "db", n_cache_size, f_memory, f_wipe); + m_filter_fileseq = MakeUnique<FlatFileSeq>(std::move(path), "fltr", FLTR_FILE_CHUNK_SIZE); +} + +bool BlockFilterIndex::Init() +{ + if (!m_db->Read(DB_FILTER_POS, m_next_filter_pos)) { + // Check that the cause of the read failure is that the key does not exist. Any other errors + // indicate database corruption or a disk failure, and starting the index would cause + // further corruption. + if (m_db->Exists(DB_FILTER_POS)) { + return error("%s: Cannot read current %s state; index may be corrupted", + __func__, GetName()); + } + + // If the DB_FILTER_POS is not set, then initialize to the first location. + m_next_filter_pos.nFile = 0; + m_next_filter_pos.nPos = 0; + } + return BaseIndex::Init(); +} + +bool BlockFilterIndex::CommitInternal(CDBBatch& batch) +{ + const FlatFilePos& pos = m_next_filter_pos; + + // Flush current filter file to disk. + CAutoFile file(m_filter_fileseq->Open(pos), SER_DISK, CLIENT_VERSION); + if (file.IsNull()) { + return error("%s: Failed to open filter file %d", __func__, pos.nFile); + } + if (!FileCommit(file.Get())) { + return error("%s: Failed to commit filter file %d", __func__, pos.nFile); + } + + batch.Write(DB_FILTER_POS, pos); + return BaseIndex::CommitInternal(batch); +} + +bool BlockFilterIndex::ReadFilterFromDisk(const FlatFilePos& pos, BlockFilter& filter) const +{ + CAutoFile filein(m_filter_fileseq->Open(pos, true), SER_DISK, CLIENT_VERSION); + if (filein.IsNull()) { + return false; + } + + uint256 block_hash; + std::vector<unsigned char> encoded_filter; + try { + filein >> block_hash >> encoded_filter; + filter = BlockFilter(GetFilterType(), block_hash, std::move(encoded_filter)); + } + catch (const std::exception& e) { + return error("%s: Failed to deserialize block filter from disk: %s", __func__, e.what()); + } + + return true; +} + +size_t BlockFilterIndex::WriteFilterToDisk(FlatFilePos& pos, const BlockFilter& filter) +{ + assert(filter.GetFilterType() == GetFilterType()); + + size_t data_size = + GetSerializeSize(filter.GetBlockHash(), CLIENT_VERSION) + + GetSerializeSize(filter.GetEncodedFilter(), CLIENT_VERSION); + + // If writing the filter would overflow the file, flush and move to the next one. + if (pos.nPos + data_size > MAX_FLTR_FILE_SIZE) { + CAutoFile last_file(m_filter_fileseq->Open(pos), SER_DISK, CLIENT_VERSION); + if (last_file.IsNull()) { + LogPrintf("%s: Failed to open filter file %d\n", __func__, pos.nFile); + return 0; + } + if (!TruncateFile(last_file.Get(), pos.nPos)) { + LogPrintf("%s: Failed to truncate filter file %d\n", __func__, pos.nFile); + return 0; + } + if (!FileCommit(last_file.Get())) { + LogPrintf("%s: Failed to commit filter file %d\n", __func__, pos.nFile); + return 0; + } + + pos.nFile++; + pos.nPos = 0; + } + + // Pre-allocate sufficient space for filter data. + bool out_of_space; + m_filter_fileseq->Allocate(pos, data_size, out_of_space); + if (out_of_space) { + LogPrintf("%s: out of disk space\n", __func__); + return 0; + } + + CAutoFile fileout(m_filter_fileseq->Open(pos), SER_DISK, CLIENT_VERSION); + if (fileout.IsNull()) { + LogPrintf("%s: Failed to open filter file %d\n", __func__, pos.nFile); + return 0; + } + + fileout << filter.GetBlockHash() << filter.GetEncodedFilter(); + return data_size; +} + +bool BlockFilterIndex::WriteBlock(const CBlock& block, const CBlockIndex* pindex) +{ + CBlockUndo block_undo; + uint256 prev_header; + + if (pindex->nHeight > 0) { + if (!UndoReadFromDisk(block_undo, pindex)) { + return false; + } + + std::pair<uint256, DBVal> read_out; + if (!m_db->Read(DBHeightKey(pindex->nHeight - 1), read_out)) { + return false; + } + + uint256 expected_block_hash = pindex->pprev->GetBlockHash(); + if (read_out.first != expected_block_hash) { + return error("%s: previous block header belongs to unexpected block %s; expected %s", + __func__, read_out.first.ToString(), expected_block_hash.ToString()); + } + + prev_header = read_out.second.header; + } + + BlockFilter filter(m_filter_type, block, block_undo); + + size_t bytes_written = WriteFilterToDisk(m_next_filter_pos, filter); + if (bytes_written == 0) return false; + + std::pair<uint256, DBVal> value; + value.first = pindex->GetBlockHash(); + value.second.hash = filter.GetHash(); + value.second.header = filter.ComputeHeader(prev_header); + value.second.pos = m_next_filter_pos; + + if (!m_db->Write(DBHeightKey(pindex->nHeight), value)) { + return false; + } + + m_next_filter_pos.nPos += bytes_written; + return true; +} + +static bool CopyHeightIndexToHashIndex(CDBIterator& db_it, CDBBatch& batch, + const std::string& index_name, + int start_height, int stop_height) +{ + DBHeightKey key(start_height); + db_it.Seek(key); + + for (int height = start_height; height <= stop_height; ++height) { + if (!db_it.GetKey(key) || key.height != height) { + return error("%s: unexpected key in %s: expected (%c, %d)", + __func__, index_name, DB_BLOCK_HEIGHT, height); + } + + std::pair<uint256, DBVal> value; + if (!db_it.GetValue(value)) { + return error("%s: unable to read value in %s at key (%c, %d)", + __func__, index_name, DB_BLOCK_HEIGHT, height); + } + + batch.Write(DBHashKey(value.first), std::move(value.second)); + + db_it.Next(); + } + return true; +} + +bool BlockFilterIndex::Rewind(const CBlockIndex* current_tip, const CBlockIndex* new_tip) +{ + assert(current_tip->GetAncestor(new_tip->nHeight) == new_tip); + + CDBBatch batch(*m_db); + std::unique_ptr<CDBIterator> db_it(m_db->NewIterator()); + + // During a reorg, we need to copy all filters for blocks that are getting disconnected from the + // height index to the hash index so we can still find them when the height index entries are + // overwritten. + if (!CopyHeightIndexToHashIndex(*db_it, batch, m_name, new_tip->nHeight, current_tip->nHeight)) { + return false; + } + + // The latest filter position gets written in Commit by the call to the BaseIndex::Rewind. + // But since this creates new references to the filter, the position should get updated here + // atomically as well in case Commit fails. + batch.Write(DB_FILTER_POS, m_next_filter_pos); + if (!m_db->WriteBatch(batch)) return false; + + return BaseIndex::Rewind(current_tip, new_tip); +} + +static bool LookupOne(const CDBWrapper& db, const CBlockIndex* block_index, DBVal& result) +{ + // First check if the result is stored under the height index and the value there matches the + // block hash. This should be the case if the block is on the active chain. + std::pair<uint256, DBVal> read_out; + if (!db.Read(DBHeightKey(block_index->nHeight), read_out)) { + return false; + } + if (read_out.first == block_index->GetBlockHash()) { + result = std::move(read_out.second); + return true; + } + + // If value at the height index corresponds to an different block, the result will be stored in + // the hash index. + return db.Read(DBHashKey(block_index->GetBlockHash()), result); +} + +static bool LookupRange(CDBWrapper& db, const std::string& index_name, int start_height, + const CBlockIndex* stop_index, std::vector<DBVal>& results) +{ + if (start_height < 0) { + return error("%s: start height (%d) is negative", __func__, start_height); + } + if (start_height > stop_index->nHeight) { + return error("%s: start height (%d) is greater than stop height (%d)", + __func__, start_height, stop_index->nHeight); + } + + size_t results_size = static_cast<size_t>(stop_index->nHeight - start_height + 1); + std::vector<std::pair<uint256, DBVal>> values(results_size); + + DBHeightKey key(start_height); + std::unique_ptr<CDBIterator> db_it(db.NewIterator()); + db_it->Seek(DBHeightKey(start_height)); + for (int height = start_height; height <= stop_index->nHeight; ++height) { + if (!db_it->Valid() || !db_it->GetKey(key) || key.height != height) { + return false; + } + + size_t i = static_cast<size_t>(height - start_height); + if (!db_it->GetValue(values[i])) { + return error("%s: unable to read value in %s at key (%c, %d)", + __func__, index_name, DB_BLOCK_HEIGHT, height); + } + + db_it->Next(); + } + + results.resize(results_size); + + // Iterate backwards through block indexes collecting results in order to access the block hash + // of each entry in case we need to look it up in the hash index. + for (const CBlockIndex* block_index = stop_index; + block_index && block_index->nHeight >= start_height; + block_index = block_index->pprev) { + uint256 block_hash = block_index->GetBlockHash(); + + size_t i = static_cast<size_t>(block_index->nHeight - start_height); + if (block_hash == values[i].first) { + results[i] = std::move(values[i].second); + continue; + } + + if (!db.Read(DBHashKey(block_hash), results[i])) { + return error("%s: unable to read value in %s at key (%c, %s)", + __func__, index_name, DB_BLOCK_HASH, block_hash.ToString()); + } + } + + return true; +} + +bool BlockFilterIndex::LookupFilter(const CBlockIndex* block_index, BlockFilter& filter_out) const +{ + DBVal entry; + if (!LookupOne(*m_db, block_index, entry)) { + return false; + } + + return ReadFilterFromDisk(entry.pos, filter_out); +} + +bool BlockFilterIndex::LookupFilterHeader(const CBlockIndex* block_index, uint256& header_out) const +{ + DBVal entry; + if (!LookupOne(*m_db, block_index, entry)) { + return false; + } + + header_out = entry.header; + return true; +} + +bool BlockFilterIndex::LookupFilterRange(int start_height, const CBlockIndex* stop_index, + std::vector<BlockFilter>& filters_out) const +{ + std::vector<DBVal> entries; + if (!LookupRange(*m_db, m_name, start_height, stop_index, entries)) { + return false; + } + + filters_out.resize(entries.size()); + auto filter_pos_it = filters_out.begin(); + for (const auto& entry : entries) { + if (!ReadFilterFromDisk(entry.pos, *filter_pos_it)) { + return false; + } + ++filter_pos_it; + } + + return true; +} + +bool BlockFilterIndex::LookupFilterHashRange(int start_height, const CBlockIndex* stop_index, + std::vector<uint256>& hashes_out) const + +{ + std::vector<DBVal> entries; + if (!LookupRange(*m_db, m_name, start_height, stop_index, entries)) { + return false; + } + + hashes_out.clear(); + hashes_out.reserve(entries.size()); + for (const auto& entry : entries) { + hashes_out.push_back(entry.hash); + } + return true; +} + +BlockFilterIndex* GetBlockFilterIndex(BlockFilterType filter_type) +{ + auto it = g_filter_indexes.find(filter_type); + return it != g_filter_indexes.end() ? &it->second : nullptr; +} + +void ForEachBlockFilterIndex(std::function<void (BlockFilterIndex&)> fn) +{ + for (auto& entry : g_filter_indexes) fn(entry.second); +} + +bool InitBlockFilterIndex(BlockFilterType filter_type, + size_t n_cache_size, bool f_memory, bool f_wipe) +{ + auto result = g_filter_indexes.emplace(std::piecewise_construct, + std::forward_as_tuple(filter_type), + std::forward_as_tuple(filter_type, + n_cache_size, f_memory, f_wipe)); + return result.second; +} + +bool DestroyBlockFilterIndex(BlockFilterType filter_type) +{ + return g_filter_indexes.erase(filter_type); +} + +void DestroyAllBlockFilterIndexes() +{ + g_filter_indexes.clear(); +} |