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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/rankings.h" | |
| 6 | |
| 7 #include "base/metrics/histogram.h" | |
| 8 #include "net/disk_cache/backend_impl.h" | |
| 9 #include "net/disk_cache/disk_format.h" | |
| 10 #include "net/disk_cache/entry_impl.h" | |
| 11 #include "net/disk_cache/errors.h" | |
| 12 #include "net/disk_cache/histogram_macros.h" | |
| 13 #include "net/disk_cache/stress_support.h" | |
| 14 | |
| 15 // Provide a BackendImpl object to macros from histogram_macros.h. | |
| 16 #define CACHE_UMA_BACKEND_IMPL_OBJ backend_ | |
| 17 | |
| 18 using base::Time; | |
| 19 using base::TimeTicks; | |
| 20 | |
| 21 namespace disk_cache { | |
| 22 // This is used by crash_cache.exe to generate unit test files. | |
| 23 NET_EXPORT_PRIVATE RankCrashes g_rankings_crash = NO_CRASH; | |
| 24 } | |
| 25 | |
| 26 namespace { | |
| 27 | |
| 28 enum Operation { | |
| 29 INSERT = 1, | |
| 30 REMOVE | |
| 31 }; | |
| 32 | |
| 33 // This class provides a simple lock for the LRU list of rankings. Whenever an | |
| 34 // entry is to be inserted or removed from the list, a transaction object should | |
| 35 // be created to keep track of the operation. If the process crashes before | |
| 36 // finishing the operation, the transaction record (stored as part of the user | |
| 37 // data on the file header) can be used to finish the operation. | |
| 38 class Transaction { | |
| 39 public: | |
| 40 // addr is the cache addres of the node being inserted or removed. We want to | |
| 41 // avoid having the compiler doing optimizations on when to read or write | |
| 42 // from user_data because it is the basis of the crash detection. Maybe | |
| 43 // volatile is not enough for that, but it should be a good hint. | |
| 44 Transaction(volatile disk_cache::LruData* data, disk_cache::Addr addr, | |
| 45 Operation op, int list); | |
| 46 ~Transaction(); | |
| 47 private: | |
| 48 volatile disk_cache::LruData* data_; | |
| 49 DISALLOW_COPY_AND_ASSIGN(Transaction); | |
| 50 }; | |
| 51 | |
| 52 Transaction::Transaction(volatile disk_cache::LruData* data, | |
| 53 disk_cache::Addr addr, Operation op, int list) | |
| 54 : data_(data) { | |
| 55 DCHECK(!data_->transaction); | |
| 56 DCHECK(addr.is_initialized()); | |
| 57 data_->operation = op; | |
| 58 data_->operation_list = list; | |
| 59 data_->transaction = addr.value(); | |
| 60 } | |
| 61 | |
| 62 Transaction::~Transaction() { | |
| 63 DCHECK(data_->transaction); | |
| 64 data_->transaction = 0; | |
| 65 data_->operation = 0; | |
| 66 data_->operation_list = 0; | |
| 67 } | |
| 68 | |
| 69 // Code locations that can generate crashes. | |
| 70 enum CrashLocation { | |
| 71 ON_INSERT_1, ON_INSERT_2, ON_INSERT_3, ON_INSERT_4, ON_REMOVE_1, ON_REMOVE_2, | |
| 72 ON_REMOVE_3, ON_REMOVE_4, ON_REMOVE_5, ON_REMOVE_6, ON_REMOVE_7, ON_REMOVE_8 | |
| 73 }; | |
| 74 | |
| 75 #ifndef NDEBUG | |
| 76 void TerminateSelf() { | |
| 77 #if defined(OS_WIN) | |
| 78 // Windows does more work on _exit() than we would like, so we force exit. | |
| 79 TerminateProcess(GetCurrentProcess(), 0); | |
| 80 #elif defined(OS_POSIX) | |
| 81 // On POSIX, _exit() will terminate the process with minimal cleanup, | |
| 82 // and it is cleaner than killing. | |
| 83 _exit(0); | |
| 84 #endif | |
| 85 } | |
| 86 #endif // NDEBUG | |
| 87 | |
| 88 // Generates a crash on debug builds, acording to the value of g_rankings_crash. | |
| 89 // This used by crash_cache.exe to generate unit-test files. | |
| 90 void GenerateCrash(CrashLocation location) { | |
| 91 #ifndef NDEBUG | |
| 92 if (disk_cache::NO_CRASH == disk_cache::g_rankings_crash) | |
| 93 return; | |
| 94 switch (location) { | |
| 95 case ON_INSERT_1: | |
| 96 switch (disk_cache::g_rankings_crash) { | |
| 97 case disk_cache::INSERT_ONE_1: | |
| 98 case disk_cache::INSERT_LOAD_1: | |
| 99 TerminateSelf(); | |
| 100 default: | |
| 101 break; | |
| 102 } | |
| 103 break; | |
| 104 case ON_INSERT_2: | |
| 105 if (disk_cache::INSERT_EMPTY_1 == disk_cache::g_rankings_crash) | |
| 106 TerminateSelf(); | |
| 107 break; | |
| 108 case ON_INSERT_3: | |
| 109 switch (disk_cache::g_rankings_crash) { | |
| 110 case disk_cache::INSERT_EMPTY_2: | |
| 111 case disk_cache::INSERT_ONE_2: | |
| 112 case disk_cache::INSERT_LOAD_2: | |
| 113 TerminateSelf(); | |
| 114 default: | |
| 115 break; | |
| 116 } | |
| 117 break; | |
| 118 case ON_INSERT_4: | |
| 119 switch (disk_cache::g_rankings_crash) { | |
| 120 case disk_cache::INSERT_EMPTY_3: | |
| 121 case disk_cache::INSERT_ONE_3: | |
| 122 TerminateSelf(); | |
| 123 default: | |
| 124 break; | |
| 125 } | |
| 126 break; | |
| 127 case ON_REMOVE_1: | |
| 128 switch (disk_cache::g_rankings_crash) { | |
| 129 case disk_cache::REMOVE_ONE_1: | |
| 130 case disk_cache::REMOVE_HEAD_1: | |
| 131 case disk_cache::REMOVE_TAIL_1: | |
| 132 case disk_cache::REMOVE_LOAD_1: | |
| 133 TerminateSelf(); | |
| 134 default: | |
| 135 break; | |
| 136 } | |
| 137 break; | |
| 138 case ON_REMOVE_2: | |
| 139 if (disk_cache::REMOVE_ONE_2 == disk_cache::g_rankings_crash) | |
| 140 TerminateSelf(); | |
| 141 break; | |
| 142 case ON_REMOVE_3: | |
| 143 if (disk_cache::REMOVE_ONE_3 == disk_cache::g_rankings_crash) | |
| 144 TerminateSelf(); | |
| 145 break; | |
| 146 case ON_REMOVE_4: | |
| 147 if (disk_cache::REMOVE_HEAD_2 == disk_cache::g_rankings_crash) | |
| 148 TerminateSelf(); | |
| 149 break; | |
| 150 case ON_REMOVE_5: | |
| 151 if (disk_cache::REMOVE_TAIL_2 == disk_cache::g_rankings_crash) | |
| 152 TerminateSelf(); | |
| 153 break; | |
| 154 case ON_REMOVE_6: | |
| 155 if (disk_cache::REMOVE_TAIL_3 == disk_cache::g_rankings_crash) | |
| 156 TerminateSelf(); | |
| 157 break; | |
| 158 case ON_REMOVE_7: | |
| 159 switch (disk_cache::g_rankings_crash) { | |
| 160 case disk_cache::REMOVE_ONE_4: | |
| 161 case disk_cache::REMOVE_LOAD_2: | |
| 162 case disk_cache::REMOVE_HEAD_3: | |
| 163 TerminateSelf(); | |
| 164 default: | |
| 165 break; | |
| 166 } | |
| 167 break; | |
| 168 case ON_REMOVE_8: | |
| 169 switch (disk_cache::g_rankings_crash) { | |
| 170 case disk_cache::REMOVE_HEAD_4: | |
| 171 case disk_cache::REMOVE_LOAD_3: | |
| 172 TerminateSelf(); | |
| 173 default: | |
| 174 break; | |
| 175 } | |
| 176 break; | |
| 177 default: | |
| 178 NOTREACHED(); | |
| 179 return; | |
| 180 } | |
| 181 #endif // NDEBUG | |
| 182 } | |
| 183 | |
| 184 // Update the timestamp fields of |node|. | |
| 185 void UpdateTimes(disk_cache::CacheRankingsBlock* node, bool modified) { | |
| 186 base::Time now = base::Time::Now(); | |
| 187 node->Data()->last_used = now.ToInternalValue(); | |
| 188 if (modified) | |
| 189 node->Data()->last_modified = now.ToInternalValue(); | |
| 190 } | |
| 191 | |
| 192 } // namespace | |
| 193 | |
| 194 namespace disk_cache { | |
| 195 | |
| 196 Rankings::ScopedRankingsBlock::ScopedRankingsBlock() : rankings_(NULL) {} | |
| 197 | |
| 198 Rankings::ScopedRankingsBlock::ScopedRankingsBlock(Rankings* rankings) | |
| 199 : rankings_(rankings) {} | |
| 200 | |
| 201 Rankings::ScopedRankingsBlock::ScopedRankingsBlock( | |
| 202 Rankings* rankings, CacheRankingsBlock* node) | |
| 203 : scoped_ptr<CacheRankingsBlock>(node), rankings_(rankings) {} | |
| 204 | |
| 205 Rankings::Iterator::Iterator(Rankings* rankings) { | |
| 206 memset(this, 0, sizeof(Iterator)); | |
| 207 my_rankings = rankings; | |
| 208 } | |
| 209 | |
| 210 Rankings::Iterator::~Iterator() { | |
| 211 for (int i = 0; i < 3; i++) | |
| 212 ScopedRankingsBlock(my_rankings, nodes[i]); | |
| 213 } | |
| 214 | |
| 215 Rankings::Rankings() : init_(false) {} | |
| 216 | |
| 217 Rankings::~Rankings() {} | |
| 218 | |
| 219 bool Rankings::Init(BackendImpl* backend, bool count_lists) { | |
| 220 DCHECK(!init_); | |
| 221 if (init_) | |
| 222 return false; | |
| 223 | |
| 224 backend_ = backend; | |
| 225 control_data_ = backend_->GetLruData(); | |
| 226 count_lists_ = count_lists; | |
| 227 | |
| 228 ReadHeads(); | |
| 229 ReadTails(); | |
| 230 | |
| 231 if (control_data_->transaction) | |
| 232 CompleteTransaction(); | |
| 233 | |
| 234 init_ = true; | |
| 235 return true; | |
| 236 } | |
| 237 | |
| 238 void Rankings::Reset() { | |
| 239 init_ = false; | |
| 240 for (int i = 0; i < LAST_ELEMENT; i++) { | |
| 241 heads_[i].set_value(0); | |
| 242 tails_[i].set_value(0); | |
| 243 } | |
| 244 control_data_ = NULL; | |
| 245 } | |
| 246 | |
| 247 void Rankings::Insert(CacheRankingsBlock* node, bool modified, List list) { | |
| 248 Trace("Insert 0x%x l %d", node->address().value(), list); | |
| 249 DCHECK(node->HasData()); | |
| 250 Addr& my_head = heads_[list]; | |
| 251 Addr& my_tail = tails_[list]; | |
| 252 Transaction lock(control_data_, node->address(), INSERT, list); | |
| 253 CacheRankingsBlock head(backend_->File(my_head), my_head); | |
| 254 if (my_head.is_initialized()) { | |
| 255 if (!GetRanking(&head)) | |
| 256 return; | |
| 257 | |
| 258 if (head.Data()->prev != my_head.value() && // Normal path. | |
| 259 head.Data()->prev != node->address().value()) { // FinishInsert(). | |
| 260 backend_->CriticalError(ERR_INVALID_LINKS); | |
| 261 return; | |
| 262 } | |
| 263 | |
| 264 head.Data()->prev = node->address().value(); | |
| 265 head.Store(); | |
| 266 GenerateCrash(ON_INSERT_1); | |
| 267 UpdateIterators(&head); | |
| 268 } | |
| 269 | |
| 270 node->Data()->next = my_head.value(); | |
| 271 node->Data()->prev = node->address().value(); | |
| 272 my_head.set_value(node->address().value()); | |
| 273 | |
| 274 if (!my_tail.is_initialized() || my_tail.value() == node->address().value()) { | |
| 275 my_tail.set_value(node->address().value()); | |
| 276 node->Data()->next = my_tail.value(); | |
| 277 WriteTail(list); | |
| 278 GenerateCrash(ON_INSERT_2); | |
| 279 } | |
| 280 | |
| 281 UpdateTimes(node, modified); | |
| 282 node->Store(); | |
| 283 GenerateCrash(ON_INSERT_3); | |
| 284 | |
| 285 // The last thing to do is move our head to point to a node already stored. | |
| 286 WriteHead(list); | |
| 287 IncrementCounter(list); | |
| 288 GenerateCrash(ON_INSERT_4); | |
| 289 backend_->FlushIndex(); | |
| 290 } | |
| 291 | |
| 292 // If a, b and r are elements on the list, and we want to remove r, the possible | |
| 293 // states for the objects if a crash happens are (where y(x, z) means for object | |
| 294 // y, prev is x and next is z): | |
| 295 // A. One element: | |
| 296 // 1. r(r, r), head(r), tail(r) initial state | |
| 297 // 2. r(r, r), head(0), tail(r) WriteHead() | |
| 298 // 3. r(r, r), head(0), tail(0) WriteTail() | |
| 299 // 4. r(0, 0), head(0), tail(0) next.Store() | |
| 300 // | |
| 301 // B. Remove a random element: | |
| 302 // 1. a(x, r), r(a, b), b(r, y), head(x), tail(y) initial state | |
| 303 // 2. a(x, r), r(a, b), b(a, y), head(x), tail(y) next.Store() | |
| 304 // 3. a(x, b), r(a, b), b(a, y), head(x), tail(y) prev.Store() | |
| 305 // 4. a(x, b), r(0, 0), b(a, y), head(x), tail(y) node.Store() | |
| 306 // | |
| 307 // C. Remove head: | |
| 308 // 1. r(r, b), b(r, y), head(r), tail(y) initial state | |
| 309 // 2. r(r, b), b(r, y), head(b), tail(y) WriteHead() | |
| 310 // 3. r(r, b), b(b, y), head(b), tail(y) next.Store() | |
| 311 // 4. r(0, 0), b(b, y), head(b), tail(y) prev.Store() | |
| 312 // | |
| 313 // D. Remove tail: | |
| 314 // 1. a(x, r), r(a, r), head(x), tail(r) initial state | |
| 315 // 2. a(x, r), r(a, r), head(x), tail(a) WriteTail() | |
| 316 // 3. a(x, a), r(a, r), head(x), tail(a) prev.Store() | |
| 317 // 4. a(x, a), r(0, 0), head(x), tail(a) next.Store() | |
| 318 void Rankings::Remove(CacheRankingsBlock* node, List list, bool strict) { | |
| 319 Trace("Remove 0x%x (0x%x 0x%x) l %d", node->address().value(), | |
| 320 node->Data()->next, node->Data()->prev, list); | |
| 321 DCHECK(node->HasData()); | |
| 322 if (strict) | |
| 323 InvalidateIterators(node); | |
| 324 | |
| 325 Addr next_addr(node->Data()->next); | |
| 326 Addr prev_addr(node->Data()->prev); | |
| 327 if (!next_addr.is_initialized() || next_addr.is_separate_file() || | |
| 328 !prev_addr.is_initialized() || prev_addr.is_separate_file()) { | |
| 329 if (next_addr.is_initialized() || prev_addr.is_initialized()) { | |
| 330 LOG(ERROR) << "Invalid rankings info."; | |
| 331 STRESS_NOTREACHED(); | |
| 332 } | |
| 333 return; | |
| 334 } | |
| 335 | |
| 336 CacheRankingsBlock next(backend_->File(next_addr), next_addr); | |
| 337 CacheRankingsBlock prev(backend_->File(prev_addr), prev_addr); | |
| 338 if (!GetRanking(&next) || !GetRanking(&prev)) { | |
| 339 STRESS_NOTREACHED(); | |
| 340 return; | |
| 341 } | |
| 342 | |
| 343 if (!CheckLinks(node, &prev, &next, &list)) | |
| 344 return; | |
| 345 | |
| 346 Transaction lock(control_data_, node->address(), REMOVE, list); | |
| 347 prev.Data()->next = next.address().value(); | |
| 348 next.Data()->prev = prev.address().value(); | |
| 349 GenerateCrash(ON_REMOVE_1); | |
| 350 | |
| 351 CacheAddr node_value = node->address().value(); | |
| 352 Addr& my_head = heads_[list]; | |
| 353 Addr& my_tail = tails_[list]; | |
| 354 if (node_value == my_head.value() || node_value == my_tail.value()) { | |
| 355 if (my_head.value() == my_tail.value()) { | |
| 356 my_head.set_value(0); | |
| 357 my_tail.set_value(0); | |
| 358 | |
| 359 WriteHead(list); | |
| 360 GenerateCrash(ON_REMOVE_2); | |
| 361 WriteTail(list); | |
| 362 GenerateCrash(ON_REMOVE_3); | |
| 363 } else if (node_value == my_head.value()) { | |
| 364 my_head.set_value(next.address().value()); | |
| 365 next.Data()->prev = next.address().value(); | |
| 366 | |
| 367 WriteHead(list); | |
| 368 GenerateCrash(ON_REMOVE_4); | |
| 369 } else if (node_value == my_tail.value()) { | |
| 370 my_tail.set_value(prev.address().value()); | |
| 371 prev.Data()->next = prev.address().value(); | |
| 372 | |
| 373 WriteTail(list); | |
| 374 GenerateCrash(ON_REMOVE_5); | |
| 375 | |
| 376 // Store the new tail to make sure we can undo the operation if we crash. | |
| 377 prev.Store(); | |
| 378 GenerateCrash(ON_REMOVE_6); | |
| 379 } | |
| 380 } | |
| 381 | |
| 382 // Nodes out of the list can be identified by invalid pointers. | |
| 383 node->Data()->next = 0; | |
| 384 node->Data()->prev = 0; | |
| 385 | |
| 386 // The last thing to get to disk is the node itself, so before that there is | |
| 387 // enough info to recover. | |
| 388 next.Store(); | |
| 389 GenerateCrash(ON_REMOVE_7); | |
| 390 prev.Store(); | |
| 391 GenerateCrash(ON_REMOVE_8); | |
| 392 node->Store(); | |
| 393 DecrementCounter(list); | |
| 394 UpdateIterators(&next); | |
| 395 UpdateIterators(&prev); | |
| 396 backend_->FlushIndex(); | |
| 397 } | |
| 398 | |
| 399 // A crash in between Remove and Insert will lead to a dirty entry not on the | |
| 400 // list. We want to avoid that case as much as we can (as while waiting for IO), | |
| 401 // but the net effect is just an assert on debug when attempting to remove the | |
| 402 // entry. Otherwise we'll need reentrant transactions, which is an overkill. | |
| 403 void Rankings::UpdateRank(CacheRankingsBlock* node, bool modified, List list) { | |
| 404 Addr& my_head = heads_[list]; | |
| 405 if (my_head.value() == node->address().value()) { | |
| 406 UpdateTimes(node, modified); | |
| 407 node->set_modified(); | |
| 408 return; | |
| 409 } | |
| 410 | |
| 411 TimeTicks start = TimeTicks::Now(); | |
| 412 Remove(node, list, true); | |
| 413 Insert(node, modified, list); | |
| 414 CACHE_UMA(AGE_MS, "UpdateRank", 0, start); | |
| 415 } | |
| 416 | |
| 417 CacheRankingsBlock* Rankings::GetNext(CacheRankingsBlock* node, List list) { | |
| 418 ScopedRankingsBlock next(this); | |
| 419 if (!node) { | |
| 420 Addr& my_head = heads_[list]; | |
| 421 if (!my_head.is_initialized()) | |
| 422 return NULL; | |
| 423 next.reset(new CacheRankingsBlock(backend_->File(my_head), my_head)); | |
| 424 } else { | |
| 425 if (!node->HasData()) | |
| 426 node->Load(); | |
| 427 Addr& my_tail = tails_[list]; | |
| 428 if (!my_tail.is_initialized()) | |
| 429 return NULL; | |
| 430 if (my_tail.value() == node->address().value()) | |
| 431 return NULL; | |
| 432 Addr address(node->Data()->next); | |
| 433 if (address.value() == node->address().value()) | |
| 434 return NULL; // Another tail? fail it. | |
| 435 next.reset(new CacheRankingsBlock(backend_->File(address), address)); | |
| 436 } | |
| 437 | |
| 438 TrackRankingsBlock(next.get(), true); | |
| 439 | |
| 440 if (!GetRanking(next.get())) | |
| 441 return NULL; | |
| 442 | |
| 443 ConvertToLongLived(next.get()); | |
| 444 if (node && !CheckSingleLink(node, next.get())) | |
| 445 return NULL; | |
| 446 | |
| 447 return next.release(); | |
| 448 } | |
| 449 | |
| 450 CacheRankingsBlock* Rankings::GetPrev(CacheRankingsBlock* node, List list) { | |
| 451 ScopedRankingsBlock prev(this); | |
| 452 if (!node) { | |
| 453 Addr& my_tail = tails_[list]; | |
| 454 if (!my_tail.is_initialized()) | |
| 455 return NULL; | |
| 456 prev.reset(new CacheRankingsBlock(backend_->File(my_tail), my_tail)); | |
| 457 } else { | |
| 458 if (!node->HasData()) | |
| 459 node->Load(); | |
| 460 Addr& my_head = heads_[list]; | |
| 461 if (!my_head.is_initialized()) | |
| 462 return NULL; | |
| 463 if (my_head.value() == node->address().value()) | |
| 464 return NULL; | |
| 465 Addr address(node->Data()->prev); | |
| 466 if (address.value() == node->address().value()) | |
| 467 return NULL; // Another head? fail it. | |
| 468 prev.reset(new CacheRankingsBlock(backend_->File(address), address)); | |
| 469 } | |
| 470 | |
| 471 TrackRankingsBlock(prev.get(), true); | |
| 472 | |
| 473 if (!GetRanking(prev.get())) | |
| 474 return NULL; | |
| 475 | |
| 476 ConvertToLongLived(prev.get()); | |
| 477 if (node && !CheckSingleLink(prev.get(), node)) | |
| 478 return NULL; | |
| 479 | |
| 480 return prev.release(); | |
| 481 } | |
| 482 | |
| 483 void Rankings::FreeRankingsBlock(CacheRankingsBlock* node) { | |
| 484 TrackRankingsBlock(node, false); | |
| 485 } | |
| 486 | |
| 487 void Rankings::TrackRankingsBlock(CacheRankingsBlock* node, | |
| 488 bool start_tracking) { | |
| 489 if (!node) | |
| 490 return; | |
| 491 | |
| 492 IteratorPair current(node->address().value(), node); | |
| 493 | |
| 494 if (start_tracking) | |
| 495 iterators_.push_back(current); | |
| 496 else | |
| 497 iterators_.remove(current); | |
| 498 } | |
| 499 | |
| 500 int Rankings::SelfCheck() { | |
| 501 int total = 0; | |
| 502 int error = 0; | |
| 503 for (int i = 0; i < LAST_ELEMENT; i++) { | |
| 504 int partial = CheckList(static_cast<List>(i)); | |
| 505 if (partial < 0 && !error) | |
| 506 error = partial; | |
| 507 else if (partial > 0) | |
| 508 total += partial; | |
| 509 } | |
| 510 | |
| 511 return error ? error : total; | |
| 512 } | |
| 513 | |
| 514 bool Rankings::SanityCheck(CacheRankingsBlock* node, bool from_list) const { | |
| 515 if (!node->VerifyHash()) | |
| 516 return false; | |
| 517 | |
| 518 const RankingsNode* data = node->Data(); | |
| 519 | |
| 520 if ((!data->next && data->prev) || (data->next && !data->prev)) | |
| 521 return false; | |
| 522 | |
| 523 // Both pointers on zero is a node out of the list. | |
| 524 if (!data->next && !data->prev && from_list) | |
| 525 return false; | |
| 526 | |
| 527 List list = NO_USE; // Initialize it to something. | |
| 528 if ((node->address().value() == data->prev) && !IsHead(data->prev, &list)) | |
| 529 return false; | |
| 530 | |
| 531 if ((node->address().value() == data->next) && !IsTail(data->next, &list)) | |
| 532 return false; | |
| 533 | |
| 534 if (!data->next && !data->prev) | |
| 535 return true; | |
| 536 | |
| 537 Addr next_addr(data->next); | |
| 538 Addr prev_addr(data->prev); | |
| 539 if (!next_addr.SanityCheckV2() || next_addr.file_type() != RANKINGS || | |
| 540 !prev_addr.SanityCheckV2() || prev_addr.file_type() != RANKINGS) | |
| 541 return false; | |
| 542 | |
| 543 return true; | |
| 544 } | |
| 545 | |
| 546 bool Rankings::DataSanityCheck(CacheRankingsBlock* node, bool from_list) const { | |
| 547 const RankingsNode* data = node->Data(); | |
| 548 if (!data->contents) | |
| 549 return false; | |
| 550 | |
| 551 // It may have never been inserted. | |
| 552 if (from_list && (!data->last_used || !data->last_modified)) | |
| 553 return false; | |
| 554 | |
| 555 return true; | |
| 556 } | |
| 557 | |
| 558 void Rankings::SetContents(CacheRankingsBlock* node, CacheAddr address) { | |
| 559 node->Data()->contents = address; | |
| 560 node->Store(); | |
| 561 } | |
| 562 | |
| 563 void Rankings::ReadHeads() { | |
| 564 for (int i = 0; i < LAST_ELEMENT; i++) | |
| 565 heads_[i] = Addr(control_data_->heads[i]); | |
| 566 } | |
| 567 | |
| 568 void Rankings::ReadTails() { | |
| 569 for (int i = 0; i < LAST_ELEMENT; i++) | |
| 570 tails_[i] = Addr(control_data_->tails[i]); | |
| 571 } | |
| 572 | |
| 573 void Rankings::WriteHead(List list) { | |
| 574 control_data_->heads[list] = heads_[list].value(); | |
| 575 } | |
| 576 | |
| 577 void Rankings::WriteTail(List list) { | |
| 578 control_data_->tails[list] = tails_[list].value(); | |
| 579 } | |
| 580 | |
| 581 bool Rankings::GetRanking(CacheRankingsBlock* rankings) { | |
| 582 if (!rankings->address().is_initialized()) | |
| 583 return false; | |
| 584 | |
| 585 TimeTicks start = TimeTicks::Now(); | |
| 586 if (!rankings->Load()) | |
| 587 return false; | |
| 588 | |
| 589 if (!SanityCheck(rankings, true)) { | |
| 590 backend_->CriticalError(ERR_INVALID_LINKS); | |
| 591 return false; | |
| 592 } | |
| 593 | |
| 594 backend_->OnEvent(Stats::OPEN_RANKINGS); | |
| 595 | |
| 596 // Note that if the cache is in read_only mode, open entries are not marked | |
| 597 // as dirty, except when an entry is doomed. We have to look for open entries. | |
| 598 if (!backend_->read_only() && !rankings->Data()->dirty) | |
| 599 return true; | |
| 600 | |
| 601 EntryImpl* entry = backend_->GetOpenEntry(rankings); | |
| 602 if (!entry) { | |
| 603 if (backend_->read_only()) | |
| 604 return true; | |
| 605 | |
| 606 // We cannot trust this entry, but we cannot initiate a cleanup from this | |
| 607 // point (we may be in the middle of a cleanup already). The entry will be | |
| 608 // deleted when detected from a regular open/create path. | |
| 609 rankings->Data()->dirty = backend_->GetCurrentEntryId() - 1; | |
| 610 if (!rankings->Data()->dirty) | |
| 611 rankings->Data()->dirty--; | |
| 612 return true; | |
| 613 } | |
| 614 | |
| 615 // Note that we should not leave this module without deleting rankings first. | |
| 616 rankings->SetData(entry->rankings()->Data()); | |
| 617 | |
| 618 CACHE_UMA(AGE_MS, "GetRankings", 0, start); | |
| 619 return true; | |
| 620 } | |
| 621 | |
| 622 void Rankings::ConvertToLongLived(CacheRankingsBlock* rankings) { | |
| 623 if (rankings->own_data()) | |
| 624 return; | |
| 625 | |
| 626 // We cannot return a shared node because we are not keeping a reference | |
| 627 // to the entry that owns the buffer. Make this node a copy of the one that | |
| 628 // we have, and let the iterator logic update it when the entry changes. | |
| 629 CacheRankingsBlock temp(NULL, Addr(0)); | |
| 630 *temp.Data() = *rankings->Data(); | |
| 631 rankings->StopSharingData(); | |
| 632 *rankings->Data() = *temp.Data(); | |
| 633 } | |
| 634 | |
| 635 void Rankings::CompleteTransaction() { | |
| 636 Addr node_addr(static_cast<CacheAddr>(control_data_->transaction)); | |
| 637 if (!node_addr.is_initialized() || node_addr.is_separate_file()) { | |
| 638 NOTREACHED(); | |
| 639 LOG(ERROR) << "Invalid rankings info."; | |
| 640 return; | |
| 641 } | |
| 642 | |
| 643 Trace("CompleteTransaction 0x%x", node_addr.value()); | |
| 644 | |
| 645 CacheRankingsBlock node(backend_->File(node_addr), node_addr); | |
| 646 if (!node.Load()) | |
| 647 return; | |
| 648 | |
| 649 node.Store(); | |
| 650 | |
| 651 Addr& my_head = heads_[control_data_->operation_list]; | |
| 652 Addr& my_tail = tails_[control_data_->operation_list]; | |
| 653 | |
| 654 // We want to leave the node inside the list. The entry must me marked as | |
| 655 // dirty, and will be removed later. Otherwise, we'll get assertions when | |
| 656 // attempting to remove the dirty entry. | |
| 657 if (INSERT == control_data_->operation) { | |
| 658 Trace("FinishInsert h:0x%x t:0x%x", my_head.value(), my_tail.value()); | |
| 659 FinishInsert(&node); | |
| 660 } else if (REMOVE == control_data_->operation) { | |
| 661 Trace("RevertRemove h:0x%x t:0x%x", my_head.value(), my_tail.value()); | |
| 662 RevertRemove(&node); | |
| 663 } else { | |
| 664 NOTREACHED(); | |
| 665 LOG(ERROR) << "Invalid operation to recover."; | |
| 666 } | |
| 667 } | |
| 668 | |
| 669 void Rankings::FinishInsert(CacheRankingsBlock* node) { | |
| 670 control_data_->transaction = 0; | |
| 671 control_data_->operation = 0; | |
| 672 Addr& my_head = heads_[control_data_->operation_list]; | |
| 673 Addr& my_tail = tails_[control_data_->operation_list]; | |
| 674 if (my_head.value() != node->address().value()) { | |
| 675 if (my_tail.value() == node->address().value()) { | |
| 676 // This part will be skipped by the logic of Insert. | |
| 677 node->Data()->next = my_tail.value(); | |
| 678 } | |
| 679 | |
| 680 Insert(node, true, static_cast<List>(control_data_->operation_list)); | |
| 681 } | |
| 682 | |
| 683 // Tell the backend about this entry. | |
| 684 backend_->RecoveredEntry(node); | |
| 685 } | |
| 686 | |
| 687 void Rankings::RevertRemove(CacheRankingsBlock* node) { | |
| 688 Addr next_addr(node->Data()->next); | |
| 689 Addr prev_addr(node->Data()->prev); | |
| 690 if (!next_addr.is_initialized() || !prev_addr.is_initialized()) { | |
| 691 // The operation actually finished. Nothing to do. | |
| 692 control_data_->transaction = 0; | |
| 693 return; | |
| 694 } | |
| 695 if (next_addr.is_separate_file() || prev_addr.is_separate_file()) { | |
| 696 NOTREACHED(); | |
| 697 LOG(WARNING) << "Invalid rankings info."; | |
| 698 control_data_->transaction = 0; | |
| 699 return; | |
| 700 } | |
| 701 | |
| 702 CacheRankingsBlock next(backend_->File(next_addr), next_addr); | |
| 703 CacheRankingsBlock prev(backend_->File(prev_addr), prev_addr); | |
| 704 if (!next.Load() || !prev.Load()) | |
| 705 return; | |
| 706 | |
| 707 CacheAddr node_value = node->address().value(); | |
| 708 DCHECK(prev.Data()->next == node_value || | |
| 709 prev.Data()->next == prev_addr.value() || | |
| 710 prev.Data()->next == next.address().value()); | |
| 711 DCHECK(next.Data()->prev == node_value || | |
| 712 next.Data()->prev == next_addr.value() || | |
| 713 next.Data()->prev == prev.address().value()); | |
| 714 | |
| 715 if (node_value != prev_addr.value()) | |
| 716 prev.Data()->next = node_value; | |
| 717 if (node_value != next_addr.value()) | |
| 718 next.Data()->prev = node_value; | |
| 719 | |
| 720 List my_list = static_cast<List>(control_data_->operation_list); | |
| 721 Addr& my_head = heads_[my_list]; | |
| 722 Addr& my_tail = tails_[my_list]; | |
| 723 if (!my_head.is_initialized() || !my_tail.is_initialized()) { | |
| 724 my_head.set_value(node_value); | |
| 725 my_tail.set_value(node_value); | |
| 726 WriteHead(my_list); | |
| 727 WriteTail(my_list); | |
| 728 } else if (my_head.value() == next.address().value()) { | |
| 729 my_head.set_value(node_value); | |
| 730 prev.Data()->next = next.address().value(); | |
| 731 WriteHead(my_list); | |
| 732 } else if (my_tail.value() == prev.address().value()) { | |
| 733 my_tail.set_value(node_value); | |
| 734 next.Data()->prev = prev.address().value(); | |
| 735 WriteTail(my_list); | |
| 736 } | |
| 737 | |
| 738 next.Store(); | |
| 739 prev.Store(); | |
| 740 control_data_->transaction = 0; | |
| 741 control_data_->operation = 0; | |
| 742 backend_->FlushIndex(); | |
| 743 } | |
| 744 | |
| 745 bool Rankings::CheckLinks(CacheRankingsBlock* node, CacheRankingsBlock* prev, | |
| 746 CacheRankingsBlock* next, List* list) { | |
| 747 CacheAddr node_addr = node->address().value(); | |
| 748 if (prev->Data()->next == node_addr && | |
| 749 next->Data()->prev == node_addr) { | |
| 750 // A regular linked node. | |
| 751 return true; | |
| 752 } | |
| 753 | |
| 754 Trace("CheckLinks 0x%x (0x%x 0x%x)", node_addr, | |
| 755 prev->Data()->next, next->Data()->prev); | |
| 756 | |
| 757 if (node_addr != prev->address().value() && | |
| 758 node_addr != next->address().value() && | |
| 759 prev->Data()->next == next->address().value() && | |
| 760 next->Data()->prev == prev->address().value()) { | |
| 761 // The list is actually ok, node is wrong. | |
| 762 Trace("node 0x%x out of list %d", node_addr, list); | |
| 763 node->Data()->next = 0; | |
| 764 node->Data()->prev = 0; | |
| 765 node->Store(); | |
| 766 return false; | |
| 767 } | |
| 768 | |
| 769 if (prev->Data()->next == node_addr || | |
| 770 next->Data()->prev == node_addr) { | |
| 771 // Only one link is weird, lets double check. | |
| 772 if (prev->Data()->next != node_addr && IsHead(node_addr, list)) | |
| 773 return true; | |
| 774 | |
| 775 if (next->Data()->prev != node_addr && IsTail(node_addr, list)) | |
| 776 return true; | |
| 777 } | |
| 778 | |
| 779 LOG(ERROR) << "Inconsistent LRU."; | |
| 780 STRESS_NOTREACHED(); | |
| 781 | |
| 782 backend_->CriticalError(ERR_INVALID_LINKS); | |
| 783 return false; | |
| 784 } | |
| 785 | |
| 786 bool Rankings::CheckSingleLink(CacheRankingsBlock* prev, | |
| 787 CacheRankingsBlock* next) { | |
| 788 if (prev->Data()->next != next->address().value() || | |
| 789 next->Data()->prev != prev->address().value()) { | |
| 790 LOG(ERROR) << "Inconsistent LRU."; | |
| 791 | |
| 792 backend_->CriticalError(ERR_INVALID_LINKS); | |
| 793 return false; | |
| 794 } | |
| 795 | |
| 796 return true; | |
| 797 } | |
| 798 | |
| 799 int Rankings::CheckList(List list) { | |
| 800 Addr last1, last2; | |
| 801 int head_items; | |
| 802 int rv = CheckListSection(list, last1, last2, true, // Head to tail. | |
| 803 &last1, &last2, &head_items); | |
| 804 if (rv == ERR_NO_ERROR) | |
| 805 return head_items; | |
| 806 | |
| 807 return rv; | |
| 808 } | |
| 809 | |
| 810 // Note that the returned error codes assume a forward walk (from head to tail) | |
| 811 // so they have to be adjusted accordingly by the caller. We use two stop values | |
| 812 // to be able to detect a corrupt node at the end that is not linked going back. | |
| 813 int Rankings::CheckListSection(List list, Addr end1, Addr end2, bool forward, | |
| 814 Addr* last, Addr* second_last, int* num_items) { | |
| 815 Addr current = forward ? heads_[list] : tails_[list]; | |
| 816 *last = *second_last = current; | |
| 817 *num_items = 0; | |
| 818 if (!current.is_initialized()) | |
| 819 return ERR_NO_ERROR; | |
| 820 | |
| 821 if (!current.SanityCheckForRankings()) | |
| 822 return ERR_INVALID_HEAD; | |
| 823 | |
| 824 scoped_ptr<CacheRankingsBlock> node; | |
| 825 Addr prev_addr(current); | |
| 826 do { | |
| 827 node.reset(new CacheRankingsBlock(backend_->File(current), current)); | |
| 828 node->Load(); | |
| 829 if (!SanityCheck(node.get(), true)) | |
| 830 return ERR_INVALID_ENTRY; | |
| 831 | |
| 832 CacheAddr next = forward ? node->Data()->next : node->Data()->prev; | |
| 833 CacheAddr prev = forward ? node->Data()->prev : node->Data()->next; | |
| 834 | |
| 835 if (prev != prev_addr.value()) | |
| 836 return ERR_INVALID_PREV; | |
| 837 | |
| 838 Addr next_addr(next); | |
| 839 if (!next_addr.SanityCheckForRankings()) | |
| 840 return ERR_INVALID_NEXT; | |
| 841 | |
| 842 prev_addr = current; | |
| 843 current = next_addr; | |
| 844 *second_last = *last; | |
| 845 *last = current; | |
| 846 (*num_items)++; | |
| 847 | |
| 848 if (next_addr == prev_addr) { | |
| 849 Addr last = forward ? tails_[list] : heads_[list]; | |
| 850 if (next_addr == last) | |
| 851 return ERR_NO_ERROR; | |
| 852 return ERR_INVALID_TAIL; | |
| 853 } | |
| 854 } while (current != end1 && current != end2); | |
| 855 return ERR_NO_ERROR; | |
| 856 } | |
| 857 | |
| 858 bool Rankings::IsHead(CacheAddr addr, List* list) const { | |
| 859 for (int i = 0; i < LAST_ELEMENT; i++) { | |
| 860 if (addr == heads_[i].value()) { | |
| 861 if (*list != i) | |
| 862 Trace("Changing list %d to %d", *list, i); | |
| 863 *list = static_cast<List>(i); | |
| 864 return true; | |
| 865 } | |
| 866 } | |
| 867 return false; | |
| 868 } | |
| 869 | |
| 870 bool Rankings::IsTail(CacheAddr addr, List* list) const { | |
| 871 for (int i = 0; i < LAST_ELEMENT; i++) { | |
| 872 if (addr == tails_[i].value()) { | |
| 873 if (*list != i) | |
| 874 Trace("Changing list %d to %d", *list, i); | |
| 875 *list = static_cast<List>(i); | |
| 876 return true; | |
| 877 } | |
| 878 } | |
| 879 return false; | |
| 880 } | |
| 881 | |
| 882 // We expect to have just a few iterators at any given time, maybe two or three, | |
| 883 // But we could have more than one pointing at the same mode. We walk the list | |
| 884 // of cache iterators and update all that are pointing to the given node. | |
| 885 void Rankings::UpdateIterators(CacheRankingsBlock* node) { | |
| 886 CacheAddr address = node->address().value(); | |
| 887 for (IteratorList::iterator it = iterators_.begin(); it != iterators_.end(); | |
| 888 ++it) { | |
| 889 if (it->first == address && it->second->HasData()) { | |
| 890 CacheRankingsBlock* other = it->second; | |
| 891 *other->Data() = *node->Data(); | |
| 892 } | |
| 893 } | |
| 894 } | |
| 895 | |
| 896 void Rankings::InvalidateIterators(CacheRankingsBlock* node) { | |
| 897 CacheAddr address = node->address().value(); | |
| 898 for (IteratorList::iterator it = iterators_.begin(); it != iterators_.end(); | |
| 899 ++it) { | |
| 900 if (it->first == address) { | |
| 901 DLOG(INFO) << "Invalidating iterator at 0x" << std::hex << address; | |
| 902 it->second->Discard(); | |
| 903 } | |
| 904 } | |
| 905 } | |
| 906 | |
| 907 void Rankings::IncrementCounter(List list) { | |
| 908 if (!count_lists_) | |
| 909 return; | |
| 910 | |
| 911 DCHECK(control_data_->sizes[list] < kint32max); | |
| 912 if (control_data_->sizes[list] < kint32max) | |
| 913 control_data_->sizes[list]++; | |
| 914 } | |
| 915 | |
| 916 void Rankings::DecrementCounter(List list) { | |
| 917 if (!count_lists_) | |
| 918 return; | |
| 919 | |
| 920 DCHECK(control_data_->sizes[list] > 0); | |
| 921 if (control_data_->sizes[list] > 0) | |
| 922 control_data_->sizes[list]--; | |
| 923 } | |
| 924 | |
| 925 } // 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