1// Copyright (c) 2012 The Chromium Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style license that can be 3// found in the LICENSE file. 4 5#include "net/disk_cache/blockfile/backend_worker_v3.h" 6 7#include "base/bind.h" 8#include "base/bind_helpers.h" 9#include "base/files/file_path.h" 10#include "base/files/file_util.h" 11#include "base/message_loop/message_loop.h" 12#include "base/strings/string_util.h" 13#include "base/strings/stringprintf.h" 14#include "base/time/time.h" 15#include "base/timer/timer.h" 16#include "net/base/net_errors.h" 17#include "net/disk_cache/blockfile/errors.h" 18#include "net/disk_cache/blockfile/experiments.h" 19#include "net/disk_cache/blockfile/file.h" 20 21using base::Time; 22using base::TimeDelta; 23using base::TimeTicks; 24 25namespace { 26 27#if defined(V3_NOT_JUST_YET_READY) 28 29const char* kIndexName = "index"; 30 31// Seems like ~240 MB correspond to less than 50k entries for 99% of the people. 32// Note that the actual target is to keep the index table load factor under 55% 33// for most users. 34const int k64kEntriesStore = 240 * 1000 * 1000; 35const int kBaseTableLen = 64 * 1024; 36const int kDefaultCacheSize = 80 * 1024 * 1024; 37 38// Avoid trimming the cache for the first 5 minutes (10 timer ticks). 39const int kTrimDelay = 10; 40 41int DesiredIndexTableLen(int32 storage_size) { 42 if (storage_size <= k64kEntriesStore) 43 return kBaseTableLen; 44 if (storage_size <= k64kEntriesStore * 2) 45 return kBaseTableLen * 2; 46 if (storage_size <= k64kEntriesStore * 4) 47 return kBaseTableLen * 4; 48 if (storage_size <= k64kEntriesStore * 8) 49 return kBaseTableLen * 8; 50 51 // The biggest storage_size for int32 requires a 4 MB table. 52 return kBaseTableLen * 16; 53} 54 55int MaxStorageSizeForTable(int table_len) { 56 return table_len * (k64kEntriesStore / kBaseTableLen); 57} 58 59size_t GetIndexSize(int table_len) { 60 size_t table_size = sizeof(disk_cache::CacheAddr) * table_len; 61 return sizeof(disk_cache::IndexHeader) + table_size; 62} 63 64// ------------------------------------------------------------------------ 65 66// Sets group for the current experiment. Returns false if the files should be 67// discarded. 68bool InitExperiment(disk_cache::IndexHeader* header, bool cache_created) { 69 if (header->experiment == disk_cache::EXPERIMENT_OLD_FILE1 || 70 header->experiment == disk_cache::EXPERIMENT_OLD_FILE2) { 71 // Discard current cache. 72 return false; 73 } 74 75 if (base::FieldTrialList::FindFullName("SimpleCacheTrial") == 76 "ExperimentControl") { 77 if (cache_created) { 78 header->experiment = disk_cache::EXPERIMENT_SIMPLE_CONTROL; 79 return true; 80 } else if (header->experiment != disk_cache::EXPERIMENT_SIMPLE_CONTROL) { 81 return false; 82 } 83 } 84 85 header->experiment = disk_cache::NO_EXPERIMENT; 86 return true; 87} 88#endif // defined(V3_NOT_JUST_YET_READY). 89 90} // namespace 91 92// ------------------------------------------------------------------------ 93 94namespace disk_cache { 95 96BackendImplV3::Worker::Worker( 97 const base::FilePath& path, 98 const scoped_refptr<base::SingleThreadTaskRunner>& main_thread) 99 : path_(path), block_files_(path), init_(false) { 100} 101 102#if defined(V3_NOT_JUST_YET_READY) 103 104int BackendImpl::SyncInit() { 105#if defined(NET_BUILD_STRESS_CACHE) 106 // Start evictions right away. 107 up_ticks_ = kTrimDelay * 2; 108#endif 109 DCHECK(!init_); 110 if (init_) 111 return net::ERR_FAILED; 112 113 bool create_files = false; 114 if (!InitBackingStore(&create_files)) { 115 ReportError(ERR_STORAGE_ERROR); 116 return net::ERR_FAILED; 117 } 118 119 num_refs_ = num_pending_io_ = max_refs_ = 0; 120 entry_count_ = byte_count_ = 0; 121 122 if (!restarted_) { 123 buffer_bytes_ = 0; 124 trace_object_ = TraceObject::GetTraceObject(); 125 // Create a recurrent timer of 30 secs. 126 int timer_delay = unit_test_ ? 1000 : 30000; 127 timer_.reset(new base::RepeatingTimer<BackendImpl>()); 128 timer_->Start(FROM_HERE, TimeDelta::FromMilliseconds(timer_delay), this, 129 &BackendImpl::OnStatsTimer); 130 } 131 132 init_ = true; 133 Trace("Init"); 134 135 if (data_->header.experiment != NO_EXPERIMENT && 136 cache_type_ != net::DISK_CACHE) { 137 // No experiment for other caches. 138 return net::ERR_FAILED; 139 } 140 141 if (!(user_flags_ & kNoRandom)) { 142 // The unit test controls directly what to test. 143 new_eviction_ = (cache_type_ == net::DISK_CACHE); 144 } 145 146 if (!CheckIndex()) { 147 ReportError(ERR_INIT_FAILED); 148 return net::ERR_FAILED; 149 } 150 151 if (!restarted_ && (create_files || !data_->header.num_entries)) 152 ReportError(ERR_CACHE_CREATED); 153 154 if (!(user_flags_ & kNoRandom) && cache_type_ == net::DISK_CACHE && 155 !InitExperiment(&data_->header, create_files)) { 156 return net::ERR_FAILED; 157 } 158 159 // We don't care if the value overflows. The only thing we care about is that 160 // the id cannot be zero, because that value is used as "not dirty". 161 // Increasing the value once per second gives us many years before we start 162 // having collisions. 163 data_->header.this_id++; 164 if (!data_->header.this_id) 165 data_->header.this_id++; 166 167 bool previous_crash = (data_->header.crash != 0); 168 data_->header.crash = 1; 169 170 if (!block_files_.Init(create_files)) 171 return net::ERR_FAILED; 172 173 // We want to minimize the changes to cache for an AppCache. 174 if (cache_type() == net::APP_CACHE) { 175 DCHECK(!new_eviction_); 176 read_only_ = true; 177 } else if (cache_type() == net::SHADER_CACHE) { 178 DCHECK(!new_eviction_); 179 } 180 181 eviction_.Init(this); 182 183 // stats_ and rankings_ may end up calling back to us so we better be enabled. 184 disabled_ = false; 185 if (!InitStats()) 186 return net::ERR_FAILED; 187 188 disabled_ = !rankings_.Init(this, new_eviction_); 189 190#if defined(STRESS_CACHE_EXTENDED_VALIDATION) 191 trace_object_->EnableTracing(false); 192 int sc = SelfCheck(); 193 if (sc < 0 && sc != ERR_NUM_ENTRIES_MISMATCH) 194 NOTREACHED(); 195 trace_object_->EnableTracing(true); 196#endif 197 198 if (previous_crash) { 199 ReportError(ERR_PREVIOUS_CRASH); 200 } else if (!restarted_) { 201 ReportError(ERR_NO_ERROR); 202 } 203 204 FlushIndex(); 205 206 return disabled_ ? net::ERR_FAILED : net::OK; 207} 208 209void BackendImpl::PrepareForRestart() { 210 // Reset the mask_ if it was not given by the user. 211 if (!(user_flags_ & kMask)) 212 mask_ = 0; 213 214 if (!(user_flags_ & kNewEviction)) 215 new_eviction_ = false; 216 217 disabled_ = true; 218 data_->header.crash = 0; 219 index_->Flush(); 220 index_ = NULL; 221 data_ = NULL; 222 block_files_.CloseFiles(); 223 rankings_.Reset(); 224 init_ = false; 225 restarted_ = true; 226} 227 228BackendImpl::~BackendImpl() { 229 if (user_flags_ & kNoRandom) { 230 // This is a unit test, so we want to be strict about not leaking entries 231 // and completing all the work. 232 background_queue_.WaitForPendingIO(); 233 } else { 234 // This is most likely not a test, so we want to do as little work as 235 // possible at this time, at the price of leaving dirty entries behind. 236 background_queue_.DropPendingIO(); 237 } 238 239 if (background_queue_.BackgroundIsCurrentThread()) { 240 // Unit tests may use the same thread for everything. 241 CleanupCache(); 242 } else { 243 background_queue_.background_thread()->PostTask( 244 FROM_HERE, base::Bind(&FinalCleanupCallback, base::Unretained(this))); 245 // http://crbug.com/74623 246 base::ThreadRestrictions::ScopedAllowWait allow_wait; 247 done_.Wait(); 248 } 249} 250 251void BackendImpl::CleanupCache() { 252 Trace("Backend Cleanup"); 253 eviction_.Stop(); 254 timer_.reset(); 255 256 if (init_) { 257 StoreStats(); 258 if (data_) 259 data_->header.crash = 0; 260 261 if (user_flags_ & kNoRandom) { 262 // This is a net_unittest, verify that we are not 'leaking' entries. 263 File::WaitForPendingIO(&num_pending_io_); 264 DCHECK(!num_refs_); 265 } else { 266 File::DropPendingIO(); 267 } 268 } 269 block_files_.CloseFiles(); 270 FlushIndex(); 271 index_ = NULL; 272 ptr_factory_.InvalidateWeakPtrs(); 273 done_.Signal(); 274} 275 276base::FilePath BackendImpl::GetFileName(Addr address) const { 277 if (!address.is_separate_file() || !address.is_initialized()) { 278 NOTREACHED(); 279 return base::FilePath(); 280 } 281 282 std::string tmp = base::StringPrintf("f_%06x", address.FileNumber()); 283 return path_.AppendASCII(tmp); 284} 285 286// We just created a new file so we're going to write the header and set the 287// file length to include the hash table (zero filled). 288bool BackendImpl::CreateBackingStore(disk_cache::File* file) { 289 AdjustMaxCacheSize(0); 290 291 IndexHeader header; 292 header.table_len = DesiredIndexTableLen(max_size_); 293 294 // We need file version 2.1 for the new eviction algorithm. 295 if (new_eviction_) 296 header.version = 0x20001; 297 298 header.create_time = Time::Now().ToInternalValue(); 299 300 if (!file->Write(&header, sizeof(header), 0)) 301 return false; 302 303 return file->SetLength(GetIndexSize(header.table_len)); 304} 305 306bool BackendImpl::InitBackingStore(bool* file_created) { 307 if (!base::CreateDirectory(path_)) 308 return false; 309 310 base::FilePath index_name = path_.AppendASCII(kIndexName); 311 312 int flags = base::PLATFORM_FILE_READ | 313 base::PLATFORM_FILE_WRITE | 314 base::PLATFORM_FILE_OPEN_ALWAYS | 315 base::PLATFORM_FILE_EXCLUSIVE_WRITE; 316 scoped_refptr<disk_cache::File> file(new disk_cache::File( 317 base::CreatePlatformFile(index_name, flags, file_created, NULL))); 318 319 if (!file->IsValid()) 320 return false; 321 322 bool ret = true; 323 if (*file_created) 324 ret = CreateBackingStore(file.get()); 325 326 file = NULL; 327 if (!ret) 328 return false; 329 330 index_ = new MappedFile(); 331 data_ = reinterpret_cast<Index*>(index_->Init(index_name, 0)); 332 if (!data_) { 333 LOG(ERROR) << "Unable to map Index file"; 334 return false; 335 } 336 337 if (index_->GetLength() < sizeof(Index)) { 338 // We verify this again on CheckIndex() but it's easier to make sure now 339 // that the header is there. 340 LOG(ERROR) << "Corrupt Index file"; 341 return false; 342 } 343 344 return true; 345} 346 347void BackendImpl::ReportError(int error) { 348 STRESS_DCHECK(!error || error == ERR_PREVIOUS_CRASH || 349 error == ERR_CACHE_CREATED); 350 351 // We transmit positive numbers, instead of direct error codes. 352 DCHECK_LE(error, 0); 353 CACHE_UMA(CACHE_ERROR, "Error", 0, error * -1); 354} 355 356 357bool BackendImpl::CheckIndex() { 358 DCHECK(data_); 359 360 size_t current_size = index_->GetLength(); 361 if (current_size < sizeof(Index)) { 362 LOG(ERROR) << "Corrupt Index file"; 363 return false; 364 } 365 366 if (new_eviction_) { 367 // We support versions 2.0 and 2.1, upgrading 2.0 to 2.1. 368 if (kIndexMagic != data_->header.magic || 369 kCurrentVersion >> 16 != data_->header.version >> 16) { 370 LOG(ERROR) << "Invalid file version or magic"; 371 return false; 372 } 373 if (kCurrentVersion == data_->header.version) { 374 // We need file version 2.1 for the new eviction algorithm. 375 UpgradeTo2_1(); 376 } 377 } else { 378 if (kIndexMagic != data_->header.magic || 379 kCurrentVersion != data_->header.version) { 380 LOG(ERROR) << "Invalid file version or magic"; 381 return false; 382 } 383 } 384 385 if (!data_->header.table_len) { 386 LOG(ERROR) << "Invalid table size"; 387 return false; 388 } 389 390 if (current_size < GetIndexSize(data_->header.table_len) || 391 data_->header.table_len & (kBaseTableLen - 1)) { 392 LOG(ERROR) << "Corrupt Index file"; 393 return false; 394 } 395 396 AdjustMaxCacheSize(data_->header.table_len); 397 398#if !defined(NET_BUILD_STRESS_CACHE) 399 if (data_->header.num_bytes < 0 || 400 (max_size_ < kint32max - kDefaultCacheSize && 401 data_->header.num_bytes > max_size_ + kDefaultCacheSize)) { 402 LOG(ERROR) << "Invalid cache (current) size"; 403 return false; 404 } 405#endif 406 407 if (data_->header.num_entries < 0) { 408 LOG(ERROR) << "Invalid number of entries"; 409 return false; 410 } 411 412 if (!mask_) 413 mask_ = data_->header.table_len - 1; 414 415 // Load the table into memory with a single read. 416 scoped_ptr<char[]> buf(new char[current_size]); 417 return index_->Read(buf.get(), current_size, 0); 418} 419 420bool BackendImpl::InitStats() { 421 Addr address(data_->header.stats); 422 int size = stats_.StorageSize(); 423 424 if (!address.is_initialized()) { 425 FileType file_type = Addr::RequiredFileType(size); 426 DCHECK_NE(file_type, EXTERNAL); 427 int num_blocks = Addr::RequiredBlocks(size, file_type); 428 429 if (!CreateBlock(file_type, num_blocks, &address)) 430 return false; 431 return stats_.Init(NULL, 0, address); 432 } 433 434 if (!address.is_block_file()) { 435 NOTREACHED(); 436 return false; 437 } 438 439 // Load the required data. 440 size = address.num_blocks() * address.BlockSize(); 441 MappedFile* file = File(address); 442 if (!file) 443 return false; 444 445 scoped_ptr<char[]> data(new char[size]); 446 size_t offset = address.start_block() * address.BlockSize() + 447 kBlockHeaderSize; 448 if (!file->Read(data.get(), size, offset)) 449 return false; 450 451 if (!stats_.Init(data.get(), size, address)) 452 return false; 453 if (cache_type_ == net::DISK_CACHE && ShouldReportAgain()) 454 stats_.InitSizeHistogram(); 455 return true; 456} 457 458#endif // defined(V3_NOT_JUST_YET_READY). 459 460int BackendImplV3::Worker::Init(const CompletionCallback& callback) { 461 return net::ERR_FAILED; 462} 463 464BackendImplV3::Worker::~Worker() { 465} 466 467} // namespace disk_cache 468