1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
|
// Copyright (c) 2018-2022 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 <hash.h>
#include <index/blockfilterindex.h>
#include <node/blockstorage.h>
#include <util/system.h>
#include <validation.h>
using node::UndoReadFromDisk;
/* 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 uint8_t DB_BLOCK_HASH{'s'};
constexpr uint8_t DB_BLOCK_HEIGHT{'t'};
constexpr uint8_t 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
/** Maximum size of the cfheaders cache
* We have a limit to prevent a bug in filling this cache
* potentially turning into an OOM. At 2000 entries, this cache
* is big enough for a 2,000,000 length block chain, which
* we should be enough until ~2047. */
constexpr size_t CF_HEADERS_CACHE_MAX_SZ{2000};
namespace {
struct DBVal {
uint256 hash;
uint256 header;
FlatFilePos pos;
SERIALIZE_METHODS(DBVal, obj) { READWRITE(obj.hash, obj.header, obj.pos); }
};
struct DBHeightKey {
int height;
explicit 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)
{
const uint8_t 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;
explicit DBHashKey(const uint256& hash_in) : hash(hash_in) {}
SERIALIZE_METHODS(DBHashKey, obj) {
uint8_t 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(obj.hash);
}
};
}; // namespace
static std::map<BlockFilterType, BlockFilterIndex> g_filter_indexes;
BlockFilterIndex::BlockFilterIndex(std::unique_ptr<interfaces::Chain> chain, BlockFilterType filter_type,
size_t n_cache_size, bool f_memory, bool f_wipe)
: BaseIndex(std::move(chain), BlockFilterTypeName(filter_type) + " block filter index")
, 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 = gArgs.GetDataDirNet() / "indexes" / "blockfilter" / fs::u8path(filter_name);
fs::create_directories(path);
m_db = std::make_unique<BaseIndex::DB>(path / "db", n_cache_size, f_memory, f_wipe);
m_filter_fileseq = std::make_unique<FlatFileSeq>(std::move(path), "fltr", FLTR_FILE_CHUNK_SIZE);
}
bool BlockFilterIndex::CustomInit(const std::optional<interfaces::BlockKey>& block)
{
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 true;
}
bool BlockFilterIndex::CustomCommit(CDBBatch& batch)
{
const FlatFilePos& pos = m_next_filter_pos;
// Flush current filter file to disk.
AutoFile file{m_filter_fileseq->Open(pos)};
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 true;
}
bool BlockFilterIndex::ReadFilterFromDisk(const FlatFilePos& pos, const uint256& hash, BlockFilter& filter) const
{
AutoFile filein{m_filter_fileseq->Open(pos, true)};
if (filein.IsNull()) {
return false;
}
// Check that the hash of the encoded_filter matches the one stored in the db.
uint256 block_hash;
std::vector<uint8_t> encoded_filter;
try {
filein >> block_hash >> encoded_filter;
uint256 result;
CHash256().Write(encoded_filter).Finalize(result);
if (result != hash) return error("Checksum mismatch in filter decode.");
filter = BlockFilter(GetFilterType(), block_hash, std::move(encoded_filter), /*skip_decode_check=*/true);
}
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) {
AutoFile last_file{m_filter_fileseq->Open(pos)};
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;
}
AutoFile fileout{m_filter_fileseq->Open(pos)};
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::CustomAppend(const interfaces::BlockInfo& block)
{
CBlockUndo block_undo;
uint256 prev_header;
if (block.height > 0) {
// pindex variable gives indexing code access to node internals. It
// will be removed in upcoming commit
const CBlockIndex* pindex = WITH_LOCK(cs_main, return m_chainstate->m_blockman.LookupBlockIndex(block.hash));
if (!UndoReadFromDisk(block_undo, pindex)) {
return false;
}
std::pair<uint256, DBVal> read_out;
if (!m_db->Read(DBHeightKey(block.height - 1), read_out)) {
return false;
}
uint256 expected_block_hash = *Assert(block.prev_hash);
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, *Assert(block.data), 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 = block.hash;
value.second.hash = filter.GetHash();
value.second.header = filter.ComputeHeader(prev_header);
value.second.pos = m_next_filter_pos;
if (!m_db->Write(DBHeightKey(block.height), 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::CustomRewind(const interfaces::BlockKey& current_tip, const interfaces::BlockKey& 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.height, current_tip.height)) {
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 true;
}
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, entry.hash, filter_out);
}
bool BlockFilterIndex::LookupFilterHeader(const CBlockIndex* block_index, uint256& header_out)
{
LOCK(m_cs_headers_cache);
bool is_checkpoint{block_index->nHeight % CFCHECKPT_INTERVAL == 0};
if (is_checkpoint) {
// Try to find the block in the headers cache if this is a checkpoint height.
auto header = m_headers_cache.find(block_index->GetBlockHash());
if (header != m_headers_cache.end()) {
header_out = header->second;
return true;
}
}
DBVal entry;
if (!LookupOne(*m_db, block_index, entry)) {
return false;
}
if (is_checkpoint &&
m_headers_cache.size() < CF_HEADERS_CACHE_MAX_SZ) {
// Add to the headers cache if this is a checkpoint height.
m_headers_cache.emplace(block_index->GetBlockHash(), entry.header);
}
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, entry.hash, *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(std::function<std::unique_ptr<interfaces::Chain>()> make_chain, 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(make_chain(), 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();
}
|