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| 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/block_files.h" | |
| 6 | |
| 7 #include "base/atomicops.h" | |
| 8 #include "base/files/file_path.h" | |
| 9 #include "base/metrics/histogram.h" | |
| 10 #include "base/strings/string_util.h" | |
| 11 #include "base/strings/stringprintf.h" | |
| 12 #include "base/threading/thread_checker.h" | |
| 13 #include "base/time/time.h" | |
| 14 #include "net/disk_cache/cache_util.h" | |
| 15 #include "net/disk_cache/file_lock.h" | |
| 16 #include "net/disk_cache/trace.h" | |
| 17 | |
| 18 using base::TimeTicks; | |
| 19 | |
| 20 namespace { | |
| 21 | |
| 22 const char* kBlockName = "data_"; | |
| 23 | |
| 24 // This array is used to perform a fast lookup of the nibble bit pattern to the | |
| 25 // type of entry that can be stored there (number of consecutive blocks). | |
| 26 const char s_types[16] = {4, 3, 2, 2, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0}; | |
| 27 | |
| 28 // Returns the type of block (number of consecutive blocks that can be stored) | |
| 29 // for a given nibble of the bitmap. | |
| 30 inline int GetMapBlockType(uint8 value) { | |
| 31 value &= 0xf; | |
| 32 return s_types[value]; | |
| 33 } | |
| 34 | |
| 35 } // namespace | |
| 36 | |
| 37 namespace disk_cache { | |
| 38 | |
| 39 BlockHeader::BlockHeader() : header_(NULL) { | |
| 40 } | |
| 41 | |
| 42 BlockHeader::BlockHeader(BlockFileHeader* header) : header_(header) { | |
| 43 } | |
| 44 | |
| 45 BlockHeader::BlockHeader(MappedFile* file) | |
| 46 : header_(reinterpret_cast<BlockFileHeader*>(file->buffer())) { | |
| 47 } | |
| 48 | |
| 49 BlockHeader::BlockHeader(const BlockHeader& other) : header_(other.header_) { | |
| 50 } | |
| 51 | |
| 52 BlockHeader::~BlockHeader() { | |
| 53 } | |
| 54 | |
| 55 bool BlockHeader::CreateMapBlock(int size, int* index) { | |
| 56 DCHECK(size > 0 && size <= kMaxNumBlocks); | |
| 57 int target = 0; | |
| 58 for (int i = size; i <= kMaxNumBlocks; i++) { | |
| 59 if (header_->empty[i - 1]) { | |
| 60 target = i; | |
| 61 break; | |
| 62 } | |
| 63 } | |
| 64 | |
| 65 if (!target) { | |
| 66 NOTREACHED(); | |
| 67 return false; | |
| 68 } | |
| 69 | |
| 70 TimeTicks start = TimeTicks::Now(); | |
| 71 // We are going to process the map on 32-block chunks (32 bits), and on every | |
| 72 // chunk, iterate through the 8 nibbles where the new block can be located. | |
| 73 int current = header_->hints[target - 1]; | |
| 74 for (int i = 0; i < header_->max_entries / 32; i++, current++) { | |
| 75 if (current == header_->max_entries / 32) | |
| 76 current = 0; | |
| 77 uint32 map_block = header_->allocation_map[current]; | |
| 78 | |
| 79 for (int j = 0; j < 8; j++, map_block >>= 4) { | |
| 80 if (GetMapBlockType(map_block) != target) | |
| 81 continue; | |
| 82 | |
| 83 disk_cache::FileLock lock(header_); | |
| 84 int index_offset = j * 4 + 4 - target; | |
| 85 *index = current * 32 + index_offset; | |
| 86 DLOG_IF(ERROR, *index / 4 != (*index + size - 1) / 4) << "Bit mismatch"; | |
| 87 uint32 to_add = ((1 << size) - 1) << index_offset; | |
| 88 header_->num_entries++; | |
| 89 | |
| 90 // Note that there is no race in the normal sense here, but if we enforce | |
| 91 // the order of memory accesses between num_entries and allocation_map, we | |
| 92 // can assert that even if we crash here, num_entries will never be less | |
| 93 // than the actual number of used blocks. | |
| 94 base::subtle::MemoryBarrier(); | |
| 95 header_->allocation_map[current] |= to_add; | |
| 96 | |
| 97 header_->hints[target - 1] = current; | |
| 98 header_->empty[target - 1]--; | |
| 99 DCHECK_GE(header_->empty[target - 1], 0); | |
| 100 if (target != size) { | |
| 101 header_->empty[target - size - 1]++; | |
| 102 } | |
| 103 HISTOGRAM_TIMES("DiskCache.CreateBlock", TimeTicks::Now() - start); | |
| 104 return true; | |
| 105 } | |
| 106 } | |
| 107 | |
| 108 // It is possible to have an undetected corruption (for example when the OS | |
| 109 // crashes), fix it here. | |
| 110 LOG(ERROR) << "Failing CreateMapBlock"; | |
| 111 FixAllocationCounters(); | |
| 112 return false; | |
| 113 } | |
| 114 | |
| 115 void BlockHeader::DeleteMapBlock(int index, int size) { | |
| 116 if (size < 0 || size > kMaxNumBlocks) { | |
| 117 NOTREACHED(); | |
| 118 return; | |
| 119 } | |
| 120 TimeTicks start = TimeTicks::Now(); | |
| 121 int byte_index = index / 8; | |
| 122 uint8* byte_map = reinterpret_cast<uint8*>(header_->allocation_map); | |
| 123 uint8 map_block = byte_map[byte_index]; | |
| 124 | |
| 125 if (index % 8 >= 4) | |
| 126 map_block >>= 4; | |
| 127 | |
| 128 // See what type of block will be available after we delete this one. | |
| 129 int bits_at_end = 4 - size - index % 4; | |
| 130 uint8 end_mask = (0xf << (4 - bits_at_end)) & 0xf; | |
| 131 bool update_counters = (map_block & end_mask) == 0; | |
| 132 uint8 new_value = map_block & ~(((1 << size) - 1) << (index % 4)); | |
| 133 int new_type = GetMapBlockType(new_value); | |
| 134 | |
| 135 disk_cache::FileLock lock(header_); | |
| 136 DCHECK((((1 << size) - 1) << (index % 8)) < 0x100); | |
| 137 uint8 to_clear = ((1 << size) - 1) << (index % 8); | |
| 138 DCHECK((byte_map[byte_index] & to_clear) == to_clear); | |
| 139 byte_map[byte_index] &= ~to_clear; | |
| 140 | |
| 141 if (update_counters) { | |
| 142 if (bits_at_end) | |
| 143 header_->empty[bits_at_end - 1]--; | |
| 144 header_->empty[new_type - 1]++; | |
| 145 DCHECK_GE(header_->empty[bits_at_end - 1], 0); | |
| 146 } | |
| 147 base::subtle::MemoryBarrier(); | |
| 148 header_->num_entries--; | |
| 149 DCHECK_GE(header_->num_entries, 0); | |
| 150 HISTOGRAM_TIMES("DiskCache.DeleteBlock", TimeTicks::Now() - start); | |
| 151 } | |
| 152 | |
| 153 // Note that this is a simplified version of DeleteMapBlock(). | |
| 154 bool BlockHeader::UsedMapBlock(int index, int size) { | |
| 155 if (size < 0 || size > kMaxNumBlocks) | |
| 156 return false; | |
| 157 | |
| 158 int byte_index = index / 8; | |
| 159 uint8* byte_map = reinterpret_cast<uint8*>(header_->allocation_map); | |
| 160 uint8 map_block = byte_map[byte_index]; | |
| 161 | |
| 162 if (index % 8 >= 4) | |
| 163 map_block >>= 4; | |
| 164 | |
| 165 DCHECK((((1 << size) - 1) << (index % 8)) < 0x100); | |
| 166 uint8 to_clear = ((1 << size) - 1) << (index % 8); | |
| 167 return ((byte_map[byte_index] & to_clear) == to_clear); | |
| 168 } | |
| 169 | |
| 170 void BlockHeader::FixAllocationCounters() { | |
| 171 for (int i = 0; i < kMaxNumBlocks; i++) { | |
| 172 header_->hints[i] = 0; | |
| 173 header_->empty[i] = 0; | |
| 174 } | |
| 175 | |
| 176 for (int i = 0; i < header_->max_entries / 32; i++) { | |
| 177 uint32 map_block = header_->allocation_map[i]; | |
| 178 | |
| 179 for (int j = 0; j < 8; j++, map_block >>= 4) { | |
| 180 int type = GetMapBlockType(map_block); | |
| 181 if (type) | |
| 182 header_->empty[type -1]++; | |
| 183 } | |
| 184 } | |
| 185 } | |
| 186 | |
| 187 bool BlockHeader::NeedToGrowBlockFile(int block_count) const { | |
| 188 bool have_space = false; | |
| 189 int empty_blocks = 0; | |
| 190 for (int i = 0; i < kMaxNumBlocks; i++) { | |
| 191 empty_blocks += header_->empty[i] * (i + 1); | |
| 192 if (i >= block_count - 1 && header_->empty[i]) | |
| 193 have_space = true; | |
| 194 } | |
| 195 | |
| 196 if (header_->next_file && (empty_blocks < kMaxBlocks / 10)) { | |
| 197 // This file is almost full but we already created another one, don't use | |
| 198 // this file yet so that it is easier to find empty blocks when we start | |
| 199 // using this file again. | |
| 200 return true; | |
| 201 } | |
| 202 return !have_space; | |
| 203 } | |
| 204 | |
| 205 bool BlockHeader::CanAllocate(int block_count) const { | |
| 206 DCHECK_GT(block_count, 0); | |
| 207 for (int i = block_count - 1; i < kMaxNumBlocks; i++) { | |
| 208 if (header_->empty[i]) | |
| 209 return true; | |
| 210 } | |
| 211 | |
| 212 return false; | |
| 213 } | |
| 214 | |
| 215 int BlockHeader::EmptyBlocks() const { | |
| 216 int empty_blocks = 0; | |
| 217 for (int i = 0; i < kMaxNumBlocks; i++) { | |
| 218 empty_blocks += header_->empty[i] * (i + 1); | |
| 219 if (header_->empty[i] < 0) | |
| 220 return 0; | |
| 221 } | |
| 222 return empty_blocks; | |
| 223 } | |
| 224 | |
| 225 int BlockHeader::MinimumAllocations() const { | |
| 226 return header_->empty[kMaxNumBlocks - 1]; | |
| 227 } | |
| 228 | |
| 229 int BlockHeader::Capacity() const { | |
| 230 return header_->max_entries; | |
| 231 } | |
| 232 | |
| 233 bool BlockHeader::ValidateCounters() const { | |
| 234 if (header_->max_entries < 0 || header_->max_entries > kMaxBlocks || | |
| 235 header_->num_entries < 0) | |
| 236 return false; | |
| 237 | |
| 238 int empty_blocks = EmptyBlocks(); | |
| 239 if (empty_blocks + header_->num_entries > header_->max_entries) | |
| 240 return false; | |
| 241 | |
| 242 return true; | |
| 243 } | |
| 244 | |
| 245 int BlockHeader::FileId() const { | |
| 246 return header_->this_file; | |
| 247 } | |
| 248 | |
| 249 int BlockHeader::NextFileId() const { | |
| 250 return header_->next_file; | |
| 251 } | |
| 252 | |
| 253 int BlockHeader::Size() const { | |
| 254 return static_cast<int>(sizeof(*header_)); | |
| 255 } | |
| 256 | |
| 257 BlockFileHeader* BlockHeader::Header() { | |
| 258 return header_; | |
| 259 } | |
| 260 | |
| 261 // ------------------------------------------------------------------------ | |
| 262 | |
| 263 BlockFiles::BlockFiles(const base::FilePath& path) | |
| 264 : init_(false), zero_buffer_(NULL), path_(path) { | |
| 265 } | |
| 266 | |
| 267 BlockFiles::~BlockFiles() { | |
| 268 if (zero_buffer_) | |
| 269 delete[] zero_buffer_; | |
| 270 CloseFiles(); | |
| 271 } | |
| 272 | |
| 273 bool BlockFiles::Init(bool create_files) { | |
| 274 DCHECK(!init_); | |
| 275 if (init_) | |
| 276 return false; | |
| 277 | |
| 278 thread_checker_.reset(new base::ThreadChecker); | |
| 279 | |
| 280 block_files_.resize(kFirstAdditionalBlockFile); | |
| 281 for (int i = 0; i < kFirstAdditionalBlockFile; i++) { | |
| 282 if (create_files) | |
| 283 if (!CreateBlockFile(i, static_cast<FileType>(i + 1), true)) | |
| 284 return false; | |
| 285 | |
| 286 if (!OpenBlockFile(i)) | |
| 287 return false; | |
| 288 | |
| 289 // Walk this chain of files removing empty ones. | |
| 290 if (!RemoveEmptyFile(static_cast<FileType>(i + 1))) | |
| 291 return false; | |
| 292 } | |
| 293 | |
| 294 init_ = true; | |
| 295 return true; | |
| 296 } | |
| 297 | |
| 298 MappedFile* BlockFiles::GetFile(Addr address) { | |
| 299 DCHECK(thread_checker_->CalledOnValidThread()); | |
| 300 DCHECK_GE(block_files_.size(), | |
| 301 static_cast<size_t>(kFirstAdditionalBlockFile)); | |
| 302 DCHECK(address.is_block_file() || !address.is_initialized()); | |
| 303 if (!address.is_initialized()) | |
| 304 return NULL; | |
| 305 | |
| 306 int file_index = address.FileNumber(); | |
| 307 if (static_cast<unsigned int>(file_index) >= block_files_.size() || | |
| 308 !block_files_[file_index]) { | |
| 309 // We need to open the file | |
| 310 if (!OpenBlockFile(file_index)) | |
| 311 return NULL; | |
| 312 } | |
| 313 DCHECK_GE(block_files_.size(), static_cast<unsigned int>(file_index)); | |
| 314 return block_files_[file_index]; | |
| 315 } | |
| 316 | |
| 317 bool BlockFiles::CreateBlock(FileType block_type, int block_count, | |
| 318 Addr* block_address) { | |
| 319 DCHECK(thread_checker_->CalledOnValidThread()); | |
| 320 DCHECK_NE(block_type, EXTERNAL); | |
| 321 DCHECK_NE(block_type, BLOCK_FILES); | |
| 322 DCHECK_NE(block_type, BLOCK_ENTRIES); | |
| 323 DCHECK_NE(block_type, BLOCK_EVICTED); | |
| 324 if (block_count < 1 || block_count > kMaxNumBlocks) | |
| 325 return false; | |
| 326 | |
| 327 if (!init_) | |
| 328 return false; | |
| 329 | |
| 330 MappedFile* file = FileForNewBlock(block_type, block_count); | |
| 331 if (!file) | |
| 332 return false; | |
| 333 | |
| 334 ScopedFlush flush(file); | |
| 335 BlockHeader file_header(file); | |
| 336 | |
| 337 int index; | |
| 338 if (!file_header.CreateMapBlock(block_count, &index)) | |
| 339 return false; | |
| 340 | |
| 341 Addr address(block_type, block_count, file_header.FileId(), index); | |
| 342 block_address->set_value(address.value()); | |
| 343 Trace("CreateBlock 0x%x", address.value()); | |
| 344 return true; | |
| 345 } | |
| 346 | |
| 347 void BlockFiles::DeleteBlock(Addr address, bool deep) { | |
| 348 DCHECK(thread_checker_->CalledOnValidThread()); | |
| 349 if (!address.is_initialized() || address.is_separate_file()) | |
| 350 return; | |
| 351 | |
| 352 if (!zero_buffer_) { | |
| 353 zero_buffer_ = new char[Addr::BlockSizeForFileType(BLOCK_4K) * 4]; | |
| 354 memset(zero_buffer_, 0, Addr::BlockSizeForFileType(BLOCK_4K) * 4); | |
| 355 } | |
| 356 MappedFile* file = GetFile(address); | |
| 357 if (!file) | |
| 358 return; | |
| 359 | |
| 360 Trace("DeleteBlock 0x%x", address.value()); | |
| 361 | |
| 362 size_t size = address.BlockSize() * address.num_blocks(); | |
| 363 size_t offset = address.start_block() * address.BlockSize() + | |
| 364 kBlockHeaderSize; | |
| 365 if (deep) | |
| 366 file->Write(zero_buffer_, size, offset); | |
| 367 | |
| 368 BlockHeader file_header(file); | |
| 369 file_header.DeleteMapBlock(address.start_block(), address.num_blocks()); | |
| 370 file->Flush(); | |
| 371 | |
| 372 if (!file_header.Header()->num_entries) { | |
| 373 // This file is now empty. Let's try to delete it. | |
| 374 FileType type = Addr::RequiredFileType(file_header.Header()->entry_size); | |
| 375 if (Addr::BlockSizeForFileType(RANKINGS) == | |
| 376 file_header.Header()->entry_size) { | |
| 377 type = RANKINGS; | |
| 378 } | |
| 379 RemoveEmptyFile(type); // Ignore failures. | |
| 380 } | |
| 381 } | |
| 382 | |
| 383 void BlockFiles::CloseFiles() { | |
| 384 if (init_) { | |
| 385 DCHECK(thread_checker_->CalledOnValidThread()); | |
| 386 } | |
| 387 init_ = false; | |
| 388 for (unsigned int i = 0; i < block_files_.size(); i++) { | |
| 389 if (block_files_[i]) { | |
| 390 block_files_[i]->Release(); | |
| 391 block_files_[i] = NULL; | |
| 392 } | |
| 393 } | |
| 394 block_files_.clear(); | |
| 395 } | |
| 396 | |
| 397 void BlockFiles::ReportStats() { | |
| 398 DCHECK(thread_checker_->CalledOnValidThread()); | |
| 399 int used_blocks[kFirstAdditionalBlockFile]; | |
| 400 int load[kFirstAdditionalBlockFile]; | |
| 401 for (int i = 0; i < kFirstAdditionalBlockFile; i++) { | |
| 402 GetFileStats(i, &used_blocks[i], &load[i]); | |
| 403 } | |
| 404 UMA_HISTOGRAM_COUNTS("DiskCache.Blocks_0", used_blocks[0]); | |
| 405 UMA_HISTOGRAM_COUNTS("DiskCache.Blocks_1", used_blocks[1]); | |
| 406 UMA_HISTOGRAM_COUNTS("DiskCache.Blocks_2", used_blocks[2]); | |
| 407 UMA_HISTOGRAM_COUNTS("DiskCache.Blocks_3", used_blocks[3]); | |
| 408 | |
| 409 UMA_HISTOGRAM_ENUMERATION("DiskCache.BlockLoad_0", load[0], 101); | |
| 410 UMA_HISTOGRAM_ENUMERATION("DiskCache.BlockLoad_1", load[1], 101); | |
| 411 UMA_HISTOGRAM_ENUMERATION("DiskCache.BlockLoad_2", load[2], 101); | |
| 412 UMA_HISTOGRAM_ENUMERATION("DiskCache.BlockLoad_3", load[3], 101); | |
| 413 } | |
| 414 | |
| 415 bool BlockFiles::IsValid(Addr address) { | |
| 416 #ifdef NDEBUG | |
| 417 return true; | |
| 418 #else | |
| 419 if (!address.is_initialized() || address.is_separate_file()) | |
| 420 return false; | |
| 421 | |
| 422 MappedFile* file = GetFile(address); | |
| 423 if (!file) | |
| 424 return false; | |
| 425 | |
| 426 BlockHeader header(file); | |
| 427 bool rv = header.UsedMapBlock(address.start_block(), address.num_blocks()); | |
| 428 DCHECK(rv); | |
| 429 | |
| 430 static bool read_contents = false; | |
| 431 if (read_contents) { | |
| 432 scoped_ptr<char[]> buffer; | |
| 433 buffer.reset(new char[Addr::BlockSizeForFileType(BLOCK_4K) * 4]); | |
| 434 size_t size = address.BlockSize() * address.num_blocks(); | |
| 435 size_t offset = address.start_block() * address.BlockSize() + | |
| 436 kBlockHeaderSize; | |
| 437 bool ok = file->Read(buffer.get(), size, offset); | |
| 438 DCHECK(ok); | |
| 439 } | |
| 440 | |
| 441 return rv; | |
| 442 #endif | |
| 443 } | |
| 444 | |
| 445 bool BlockFiles::CreateBlockFile(int index, FileType file_type, bool force) { | |
| 446 base::FilePath name = Name(index); | |
| 447 int flags = | |
| 448 force ? base::PLATFORM_FILE_CREATE_ALWAYS : base::PLATFORM_FILE_CREATE; | |
| 449 flags |= base::PLATFORM_FILE_WRITE | base::PLATFORM_FILE_EXCLUSIVE_WRITE; | |
| 450 | |
| 451 scoped_refptr<File> file(new File( | |
| 452 base::CreatePlatformFile(name, flags, NULL, NULL))); | |
| 453 if (!file->IsValid()) | |
| 454 return false; | |
| 455 | |
| 456 BlockFileHeader header; | |
| 457 memset(&header, 0, sizeof(header)); | |
| 458 header.magic = kBlockMagic; | |
| 459 header.version = kBlockVersion2; | |
| 460 header.entry_size = Addr::BlockSizeForFileType(file_type); | |
| 461 header.this_file = static_cast<int16>(index); | |
| 462 DCHECK(index <= kint16max && index >= 0); | |
| 463 | |
| 464 return file->Write(&header, sizeof(header), 0); | |
| 465 } | |
| 466 | |
| 467 bool BlockFiles::OpenBlockFile(int index) { | |
| 468 if (block_files_.size() - 1 < static_cast<unsigned int>(index)) { | |
| 469 DCHECK(index > 0); | |
| 470 int to_add = index - static_cast<int>(block_files_.size()) + 1; | |
| 471 block_files_.resize(block_files_.size() + to_add); | |
| 472 } | |
| 473 | |
| 474 base::FilePath name = Name(index); | |
| 475 scoped_refptr<MappedFile> file(new MappedFile()); | |
| 476 | |
| 477 if (!file->Init(name, kBlockHeaderSize)) { | |
| 478 LOG(ERROR) << "Failed to open " << name.value(); | |
| 479 return false; | |
| 480 } | |
| 481 | |
| 482 size_t file_len = file->GetLength(); | |
| 483 if (file_len < static_cast<size_t>(kBlockHeaderSize)) { | |
| 484 LOG(ERROR) << "File too small " << name.value(); | |
| 485 return false; | |
| 486 } | |
| 487 | |
| 488 BlockHeader file_header(file.get()); | |
| 489 BlockFileHeader* header = file_header.Header(); | |
| 490 if (kBlockMagic != header->magic || kBlockVersion2 != header->version) { | |
| 491 LOG(ERROR) << "Invalid file version or magic " << name.value(); | |
| 492 return false; | |
| 493 } | |
| 494 | |
| 495 if (header->updating || !file_header.ValidateCounters()) { | |
| 496 // Last instance was not properly shutdown, or counters are out of sync. | |
| 497 if (!FixBlockFileHeader(file.get())) { | |
| 498 LOG(ERROR) << "Unable to fix block file " << name.value(); | |
| 499 return false; | |
| 500 } | |
| 501 } | |
| 502 | |
| 503 if (static_cast<int>(file_len) < | |
| 504 header->max_entries * header->entry_size + kBlockHeaderSize) { | |
| 505 LOG(ERROR) << "File too small " << name.value(); | |
| 506 return false; | |
| 507 } | |
| 508 | |
| 509 if (index == 0) { | |
| 510 // Load the links file into memory with a single read. | |
| 511 scoped_ptr<char[]> buf(new char[file_len]); | |
| 512 if (!file->Read(buf.get(), file_len, 0)) | |
| 513 return false; | |
| 514 } | |
| 515 | |
| 516 ScopedFlush flush(file.get()); | |
| 517 DCHECK(!block_files_[index]); | |
| 518 file.swap(&block_files_[index]); | |
| 519 return true; | |
| 520 } | |
| 521 | |
| 522 bool BlockFiles::GrowBlockFile(MappedFile* file, BlockFileHeader* header) { | |
| 523 if (kMaxBlocks == header->max_entries) | |
| 524 return false; | |
| 525 | |
| 526 ScopedFlush flush(file); | |
| 527 DCHECK(!header->empty[3]); | |
| 528 int new_size = header->max_entries + 1024; | |
| 529 if (new_size > kMaxBlocks) | |
| 530 new_size = kMaxBlocks; | |
| 531 | |
| 532 int new_size_bytes = new_size * header->entry_size + sizeof(*header); | |
| 533 | |
| 534 if (!file->SetLength(new_size_bytes)) { | |
| 535 // Most likely we are trying to truncate the file, so the header is wrong. | |
| 536 if (header->updating < 10 && !FixBlockFileHeader(file)) { | |
| 537 // If we can't fix the file increase the lock guard so we'll pick it on | |
| 538 // the next start and replace it. | |
| 539 header->updating = 100; | |
| 540 return false; | |
| 541 } | |
| 542 return (header->max_entries >= new_size); | |
| 543 } | |
| 544 | |
| 545 FileLock lock(header); | |
| 546 header->empty[3] = (new_size - header->max_entries) / 4; // 4 blocks entries | |
| 547 header->max_entries = new_size; | |
| 548 | |
| 549 return true; | |
| 550 } | |
| 551 | |
| 552 MappedFile* BlockFiles::FileForNewBlock(FileType block_type, int block_count) { | |
| 553 COMPILE_ASSERT(RANKINGS == 1, invalid_file_type); | |
| 554 MappedFile* file = block_files_[block_type - 1]; | |
| 555 BlockHeader file_header(file); | |
| 556 | |
| 557 TimeTicks start = TimeTicks::Now(); | |
| 558 while (file_header.NeedToGrowBlockFile(block_count)) { | |
| 559 if (kMaxBlocks == file_header.Header()->max_entries) { | |
| 560 file = NextFile(file); | |
| 561 if (!file) | |
| 562 return NULL; | |
| 563 file_header = BlockHeader(file); | |
| 564 continue; | |
| 565 } | |
| 566 | |
| 567 if (!GrowBlockFile(file, file_header.Header())) | |
| 568 return NULL; | |
| 569 break; | |
| 570 } | |
| 571 HISTOGRAM_TIMES("DiskCache.GetFileForNewBlock", TimeTicks::Now() - start); | |
| 572 return file; | |
| 573 } | |
| 574 | |
| 575 MappedFile* BlockFiles::NextFile(MappedFile* file) { | |
| 576 ScopedFlush flush(file); | |
| 577 BlockFileHeader* header = reinterpret_cast<BlockFileHeader*>(file->buffer()); | |
| 578 int new_file = header->next_file; | |
| 579 if (!new_file) { | |
| 580 // RANKINGS is not reported as a type for small entries, but we may be | |
| 581 // extending the rankings block file. | |
| 582 FileType type = Addr::RequiredFileType(header->entry_size); | |
| 583 if (header->entry_size == Addr::BlockSizeForFileType(RANKINGS)) | |
| 584 type = RANKINGS; | |
| 585 | |
| 586 new_file = CreateNextBlockFile(type); | |
| 587 if (!new_file) | |
| 588 return NULL; | |
| 589 | |
| 590 FileLock lock(header); | |
| 591 header->next_file = new_file; | |
| 592 } | |
| 593 | |
| 594 // Only the block_file argument is relevant for what we want. | |
| 595 Addr address(BLOCK_256, 1, new_file, 0); | |
| 596 return GetFile(address); | |
| 597 } | |
| 598 | |
| 599 int BlockFiles::CreateNextBlockFile(FileType block_type) { | |
| 600 for (int i = kFirstAdditionalBlockFile; i <= kMaxBlockFile; i++) { | |
| 601 if (CreateBlockFile(i, block_type, false)) | |
| 602 return i; | |
| 603 } | |
| 604 return 0; | |
| 605 } | |
| 606 | |
| 607 // We walk the list of files for this particular block type, deleting the ones | |
| 608 // that are empty. | |
| 609 bool BlockFiles::RemoveEmptyFile(FileType block_type) { | |
| 610 MappedFile* file = block_files_[block_type - 1]; | |
| 611 BlockFileHeader* header = reinterpret_cast<BlockFileHeader*>(file->buffer()); | |
| 612 | |
| 613 while (header->next_file) { | |
| 614 // Only the block_file argument is relevant for what we want. | |
| 615 Addr address(BLOCK_256, 1, header->next_file, 0); | |
| 616 MappedFile* next_file = GetFile(address); | |
| 617 if (!next_file) | |
| 618 return false; | |
| 619 | |
| 620 BlockFileHeader* next_header = | |
| 621 reinterpret_cast<BlockFileHeader*>(next_file->buffer()); | |
| 622 if (!next_header->num_entries) { | |
| 623 DCHECK_EQ(next_header->entry_size, header->entry_size); | |
| 624 // Delete next_file and remove it from the chain. | |
| 625 int file_index = header->next_file; | |
| 626 header->next_file = next_header->next_file; | |
| 627 DCHECK(block_files_.size() >= static_cast<unsigned int>(file_index)); | |
| 628 file->Flush(); | |
| 629 | |
| 630 // We get a new handle to the file and release the old one so that the | |
| 631 // file gets unmmaped... so we can delete it. | |
| 632 base::FilePath name = Name(file_index); | |
| 633 scoped_refptr<File> this_file(new File(false)); | |
| 634 this_file->Init(name); | |
| 635 block_files_[file_index]->Release(); | |
| 636 block_files_[file_index] = NULL; | |
| 637 | |
| 638 int failure = DeleteCacheFile(name) ? 0 : 1; | |
| 639 UMA_HISTOGRAM_COUNTS("DiskCache.DeleteFailed2", failure); | |
| 640 if (failure) | |
| 641 LOG(ERROR) << "Failed to delete " << name.value() << " from the cache."; | |
| 642 continue; | |
| 643 } | |
| 644 | |
| 645 header = next_header; | |
| 646 file = next_file; | |
| 647 } | |
| 648 return true; | |
| 649 } | |
| 650 | |
| 651 // Note that we expect to be called outside of a FileLock... however, we cannot | |
| 652 // DCHECK on header->updating because we may be fixing a crash. | |
| 653 bool BlockFiles::FixBlockFileHeader(MappedFile* file) { | |
| 654 ScopedFlush flush(file); | |
| 655 BlockHeader file_header(file); | |
| 656 int file_size = static_cast<int>(file->GetLength()); | |
| 657 if (file_size < file_header.Size()) | |
| 658 return false; // file_size > 2GB is also an error. | |
| 659 | |
| 660 const int kMinBlockSize = 36; | |
| 661 const int kMaxBlockSize = 4096; | |
| 662 BlockFileHeader* header = file_header.Header(); | |
| 663 if (header->entry_size < kMinBlockSize || | |
| 664 header->entry_size > kMaxBlockSize || header->num_entries < 0) | |
| 665 return false; | |
| 666 | |
| 667 // Make sure that we survive crashes. | |
| 668 header->updating = 1; | |
| 669 int expected = header->entry_size * header->max_entries + file_header.Size(); | |
| 670 if (file_size != expected) { | |
| 671 int max_expected = header->entry_size * kMaxBlocks + file_header.Size(); | |
| 672 if (file_size < expected || header->empty[3] || file_size > max_expected) { | |
| 673 NOTREACHED(); | |
| 674 LOG(ERROR) << "Unexpected file size"; | |
| 675 return false; | |
| 676 } | |
| 677 // We were in the middle of growing the file. | |
| 678 int num_entries = (file_size - file_header.Size()) / header->entry_size; | |
| 679 header->max_entries = num_entries; | |
| 680 } | |
| 681 | |
| 682 file_header.FixAllocationCounters(); | |
| 683 int empty_blocks = file_header.EmptyBlocks(); | |
| 684 if (empty_blocks + header->num_entries > header->max_entries) | |
| 685 header->num_entries = header->max_entries - empty_blocks; | |
| 686 | |
| 687 if (!file_header.ValidateCounters()) | |
| 688 return false; | |
| 689 | |
| 690 header->updating = 0; | |
| 691 return true; | |
| 692 } | |
| 693 | |
| 694 // We are interested in the total number of blocks used by this file type, and | |
| 695 // the max number of blocks that we can store (reported as the percentage of | |
| 696 // used blocks). In order to find out the number of used blocks, we have to | |
| 697 // substract the empty blocks from the total blocks for each file in the chain. | |
| 698 void BlockFiles::GetFileStats(int index, int* used_count, int* load) { | |
| 699 int max_blocks = 0; | |
| 700 *used_count = 0; | |
| 701 *load = 0; | |
| 702 for (;;) { | |
| 703 if (!block_files_[index] && !OpenBlockFile(index)) | |
| 704 return; | |
| 705 | |
| 706 BlockFileHeader* header = | |
| 707 reinterpret_cast<BlockFileHeader*>(block_files_[index]->buffer()); | |
| 708 | |
| 709 max_blocks += header->max_entries; | |
| 710 int used = header->max_entries; | |
| 711 for (int i = 0; i < kMaxNumBlocks; i++) { | |
| 712 used -= header->empty[i] * (i + 1); | |
| 713 DCHECK_GE(used, 0); | |
| 714 } | |
| 715 *used_count += used; | |
| 716 | |
| 717 if (!header->next_file) | |
| 718 break; | |
| 719 index = header->next_file; | |
| 720 } | |
| 721 if (max_blocks) | |
| 722 *load = *used_count * 100 / max_blocks; | |
| 723 } | |
| 724 | |
| 725 base::FilePath BlockFiles::Name(int index) { | |
| 726 // The file format allows for 256 files. | |
| 727 DCHECK(index < 256 && index >= 0); | |
| 728 std::string tmp = base::StringPrintf("%s%d", kBlockName, index); | |
| 729 return path_.AppendASCII(tmp); | |
| 730 } | |
| 731 | |
| 732 } // namespace disk_cache | |
| OLD | NEW |
|---|
Chromium Code Reviews
Issue 121643003:
Reorganize net/disk_cache into backend specific directories. (Closed)
Base URL: svn://svn.chromium.org/chrome/trunk/src