1 /* 2 * Copyright 2011, Jérôme Duval, korli@users.berlios.de. 3 * Copyright 2008-2010, Axel Dörfler, axeld@pinc-software.de. 4 * This file may be used under the terms of the MIT License. 5 */ 6 7 8 //! Superblock, mounting, etc. 9 10 11 #include "Volume.h" 12 #include "BPlusTree.h" 13 #include "CachedBlock.h" 14 #include "Chunk.h" 15 #include "Inode.h" 16 17 18 //#define TRACE_BTRFS 19 #ifdef TRACE_BTRFS 20 # define TRACE(x...) dprintf("\33[34mbtrfs:\33[0m " x) 21 #else 22 # define TRACE(x...) ; 23 #endif 24 # define ERROR(x...) dprintf("\33[34mbtrfs:\33[0m " x) 25 26 27 class DeviceOpener { 28 public: 29 DeviceOpener(int fd, int mode); 30 DeviceOpener(const char* device, int mode); 31 ~DeviceOpener(); 32 33 int Open(const char* device, int mode); 34 int Open(int fd, int mode); 35 void* InitCache(off_t numBlocks, uint32 blockSize); 36 void RemoveCache(bool allowWrites); 37 38 void Keep(); 39 40 int Device() const { return fDevice; } 41 int Mode() const { return fMode; } 42 bool IsReadOnly() const 43 { return _IsReadOnly(fMode); } 44 45 status_t GetSize(off_t* _size, uint32* _blockSize = NULL); 46 47 private: 48 static bool _IsReadOnly(int mode) 49 { return (mode & O_RWMASK) == O_RDONLY;} 50 static bool _IsReadWrite(int mode) 51 { return (mode & O_RWMASK) == O_RDWR;} 52 53 int fDevice; 54 int fMode; 55 void* fBlockCache; 56 }; 57 58 59 DeviceOpener::DeviceOpener(const char* device, int mode) 60 : 61 fBlockCache(NULL) 62 { 63 Open(device, mode); 64 } 65 66 67 DeviceOpener::DeviceOpener(int fd, int mode) 68 : 69 fBlockCache(NULL) 70 { 71 Open(fd, mode); 72 } 73 74 75 DeviceOpener::~DeviceOpener() 76 { 77 if (fDevice >= 0) { 78 RemoveCache(false); 79 close(fDevice); 80 } 81 } 82 83 84 int 85 DeviceOpener::Open(const char* device, int mode) 86 { 87 fDevice = open(device, mode | O_NOCACHE); 88 if (fDevice < 0) 89 fDevice = errno; 90 91 if (fDevice < 0 && _IsReadWrite(mode)) { 92 // try again to open read-only (don't rely on a specific error code) 93 return Open(device, O_RDONLY | O_NOCACHE); 94 } 95 96 if (fDevice >= 0) { 97 // opening succeeded 98 fMode = mode; 99 if (_IsReadWrite(mode)) { 100 // check out if the device really allows for read/write access 101 device_geometry geometry; 102 if (!ioctl(fDevice, B_GET_GEOMETRY, &geometry)) { 103 if (geometry.read_only) { 104 // reopen device read-only 105 close(fDevice); 106 return Open(device, O_RDONLY | O_NOCACHE); 107 } 108 } 109 } 110 } 111 112 return fDevice; 113 } 114 115 116 int 117 DeviceOpener::Open(int fd, int mode) 118 { 119 fDevice = dup(fd); 120 if (fDevice < 0) 121 return errno; 122 123 fMode = mode; 124 125 return fDevice; 126 } 127 128 129 void* 130 DeviceOpener::InitCache(off_t numBlocks, uint32 blockSize) 131 { 132 return fBlockCache = block_cache_create(fDevice, numBlocks, blockSize, 133 IsReadOnly()); 134 } 135 136 137 void 138 DeviceOpener::RemoveCache(bool allowWrites) 139 { 140 if (fBlockCache == NULL) 141 return; 142 143 block_cache_delete(fBlockCache, allowWrites); 144 fBlockCache = NULL; 145 } 146 147 148 void 149 DeviceOpener::Keep() 150 { 151 fDevice = -1; 152 } 153 154 155 /*! Returns the size of the device in bytes. It uses B_GET_GEOMETRY 156 to compute the size, or fstat() if that failed. 157 */ 158 status_t 159 DeviceOpener::GetSize(off_t* _size, uint32* _blockSize) 160 { 161 device_geometry geometry; 162 if (ioctl(fDevice, B_GET_GEOMETRY, &geometry) < 0) { 163 // maybe it's just a file 164 struct stat stat; 165 if (fstat(fDevice, &stat) < 0) 166 return B_ERROR; 167 168 if (_size) 169 *_size = stat.st_size; 170 if (_blockSize) // that shouldn't cause us any problems 171 *_blockSize = 512; 172 173 return B_OK; 174 } 175 176 if (_size) { 177 *_size = 1ULL * geometry.head_count * geometry.cylinder_count 178 * geometry.sectors_per_track * geometry.bytes_per_sector; 179 } 180 if (_blockSize) 181 *_blockSize = geometry.bytes_per_sector; 182 183 return B_OK; 184 } 185 186 187 // #pragma mark - 188 189 190 bool 191 btrfs_super_block::IsValid() 192 { 193 // TODO: check some more values! 194 if (strncmp(magic, BTRFS_SUPER_BLOCK_MAGIC, sizeof(magic)) != 0) 195 return false; 196 197 return true; 198 } 199 200 201 // #pragma mark - 202 203 204 Volume::Volume(fs_volume* volume) 205 : 206 fFSVolume(volume), 207 fFlags(0), 208 fChunk(NULL), 209 fChunkTree(NULL) 210 { 211 mutex_init(&fLock, "btrfs volume"); 212 } 213 214 215 Volume::~Volume() 216 { 217 TRACE("Volume destructor.\n"); 218 } 219 220 221 bool 222 Volume::IsValidSuperBlock() 223 { 224 return fSuperBlock.IsValid(); 225 } 226 227 228 const char* 229 Volume::Name() const 230 { 231 if (fSuperBlock.label[0]) 232 return fSuperBlock.label; 233 234 return fName; 235 } 236 237 238 status_t 239 Volume::Mount(const char* deviceName, uint32 flags) 240 { 241 flags |= B_MOUNT_READ_ONLY; 242 // we only support read-only for now 243 244 if ((flags & B_MOUNT_READ_ONLY) != 0) { 245 TRACE("Volume::Mount(): Read only\n"); 246 } else { 247 TRACE("Volume::Mount(): Read write\n"); 248 } 249 250 DeviceOpener opener(deviceName, (flags & B_MOUNT_READ_ONLY) != 0 251 ? O_RDONLY : O_RDWR); 252 fDevice = opener.Device(); 253 if (fDevice < B_OK) { 254 ERROR("Volume::Mount(): couldn't open device\n"); 255 return fDevice; 256 } 257 258 if (opener.IsReadOnly()) 259 fFlags |= VOLUME_READ_ONLY; 260 261 // read the superblock 262 status_t status = Identify(fDevice, &fSuperBlock); 263 if (status != B_OK) { 264 ERROR("Volume::Mount(): Identify() failed\n"); 265 return status; 266 } 267 268 fBlockSize = fSuperBlock.BlockSize(); 269 TRACE("block size %" B_PRIu32 "\n", fBlockSize); 270 271 uint8* start = (uint8*)&fSuperBlock.system_chunk_array[0]; 272 uint8* end = (uint8*)&fSuperBlock.system_chunk_array[2048]; 273 while (start < end) { 274 struct btrfs_key* key = (struct btrfs_key*)start; 275 TRACE("system_chunk_array object_id 0x%" B_PRIx64 " offset 0x%" 276 B_PRIx64 " type 0x%x\n", key->ObjectID(), key->Offset(), 277 key->Type()); 278 if (key->Type() != BTRFS_KEY_TYPE_CHUNK_ITEM) { 279 break; 280 } 281 282 struct btrfs_chunk* chunk = (struct btrfs_chunk*)(key + 1); 283 fChunk = new(std::nothrow) Chunk(chunk, key->Offset()); 284 if (fChunk == NULL) 285 return B_ERROR; 286 start += sizeof(struct btrfs_key) + fChunk->Size(); 287 } 288 289 TRACE("Volume::Mount() generation: %" B_PRIu64 "\n", 290 fSuperBlock.Generation()); 291 fsblock_t physical = 0; 292 FindBlock(fSuperBlock.Root(), physical); 293 TRACE("Volume::Mount() root: %" B_PRIu64 " (physical %" B_PRIu64 ")\n", 294 fSuperBlock.Root(), physical); 295 FindBlock(fSuperBlock.ChunkRoot(), physical); 296 TRACE("Volume::Mount() chunk_root: %" B_PRIu64 " (physical %" B_PRIu64 297 ")\n", fSuperBlock.ChunkRoot(), physical); 298 FindBlock(fSuperBlock.LogRoot(), physical); 299 TRACE("Volume::Mount() log_root: %" B_PRIu64 " (physical %" B_PRIu64 ")\n", 300 fSuperBlock.LogRoot(), physical); 301 302 // check if the device size is large enough to hold the file system 303 off_t diskSize; 304 status = opener.GetSize(&diskSize); 305 if (status != B_OK) 306 return status; 307 if (diskSize < (off_t)fSuperBlock.TotalSize()) 308 return B_BAD_VALUE; 309 310 fBlockCache = opener.InitCache(fSuperBlock.TotalSize() / fBlockSize, 311 fBlockSize); 312 if (fBlockCache == NULL) 313 return B_ERROR; 314 315 TRACE("Volume::Mount(): Initialized block cache: %p\n", fBlockCache); 316 317 fChunkTree = new(std::nothrow) BPlusTree(this, fSuperBlock.ChunkRoot()); 318 if (fChunkTree == NULL) 319 return B_NO_MEMORY; 320 321 FindBlock(fSuperBlock.Root(), physical); 322 TRACE("Volume::Mount() root: %" B_PRIu64 " (physical %" B_PRIu64 ")\n", 323 fSuperBlock.Root(), physical); 324 FindBlock(fSuperBlock.ChunkRoot(), physical); 325 TRACE("Volume::Mount() chunk_root: %" B_PRIu64 " (physical %" B_PRIu64 326 ")\n", fSuperBlock.ChunkRoot(), physical); 327 FindBlock(fSuperBlock.LogRoot(), physical); 328 TRACE("Volume::Mount() log_root: %" B_PRIu64 " (physical %" B_PRIu64 ")\n", 329 fSuperBlock.LogRoot(), physical); 330 331 fRootTree = new(std::nothrow) BPlusTree(this, fSuperBlock.Root()); 332 if (fRootTree == NULL) 333 return B_NO_MEMORY; 334 TRACE("Volume::Mount(): Searching extent root\n"); 335 struct btrfs_key search_key; 336 search_key.SetOffset(0); 337 search_key.SetType(BTRFS_KEY_TYPE_ROOT_ITEM); 338 search_key.SetObjectID(BTRFS_OBJECT_ID_EXTENT_TREE); 339 struct btrfs_root* root; 340 if (fRootTree->FindNext(search_key, (void**)&root) != B_OK) { 341 ERROR("Volume::Mount(): Couldn't find extent root\n"); 342 return B_ERROR; 343 } 344 TRACE("Volume::Mount(): Found extent root: %" B_PRIu64 "\n", 345 root->BlockNum()); 346 fExtentTree = new(std::nothrow) BPlusTree(this, root->BlockNum()); 347 free(root); 348 if (fExtentTree == NULL) 349 return B_NO_MEMORY; 350 351 search_key.SetOffset(0); 352 search_key.SetObjectID(BTRFS_OBJECT_ID_FS_TREE); 353 if (fRootTree->FindNext(search_key, (void**)&root) != B_OK) { 354 ERROR("Volume::Mount(): Couldn't find fs root\n"); 355 return B_ERROR; 356 } 357 TRACE("Volume::Mount(): Found fs root: %" B_PRIu64 "\n", root->BlockNum()); 358 fFSTree = new(std::nothrow) BPlusTree(this, root->BlockNum()); 359 free(root); 360 if (fFSTree == NULL) 361 return B_NO_MEMORY; 362 363 search_key.SetOffset(0); 364 search_key.SetObjectID(BTRFS_OBJECT_ID_DEV_TREE); 365 if (fRootTree->FindNext(search_key, (void**)&root) != B_OK) { 366 ERROR("Volume::Mount(): Couldn't find dev root\n"); 367 return B_ERROR; 368 } 369 TRACE("Volume::Mount(): Found dev root: %" B_PRIu64 "\n", 370 root->BlockNum()); 371 fDevTree = new(std::nothrow) BPlusTree(this, root->BlockNum()); 372 free(root); 373 if (fDevTree == NULL) 374 return B_NO_MEMORY; 375 376 search_key.SetOffset(0); 377 search_key.SetObjectID(BTRFS_OBJECT_ID_CHECKSUM_TREE); 378 if (fRootTree->FindNext(search_key, (void**)&root) != B_OK) { 379 ERROR("Volume::Mount(): Couldn't find checksum root\n"); 380 return B_ERROR; 381 } 382 TRACE("Volume::Mount(): Found checksum root: %" B_PRIu64 "\n", 383 root->BlockNum()); 384 fChecksumTree = new(std::nothrow) BPlusTree(this, root->BlockNum()); 385 free(root); 386 if (fChecksumTree == NULL) 387 return B_NO_MEMORY; 388 389 // ready 390 status = get_vnode(fFSVolume, BTRFS_OBJECT_ID_CHUNK_TREE, 391 (void**)&fRootNode); 392 if (status != B_OK) { 393 ERROR("could not create root node: get_vnode() failed!\n"); 394 return status; 395 } 396 397 TRACE("Volume::Mount(): Found root node: %" B_PRIu64 " (%s)\n", 398 fRootNode->ID(), strerror(fRootNode->InitCheck())); 399 400 // all went fine 401 opener.Keep(); 402 403 if (!fSuperBlock.label[0]) { 404 // generate a more or less descriptive volume name 405 off_t divisor = 1ULL << 40; 406 char unit = 'T'; 407 if (diskSize < divisor) { 408 divisor = 1UL << 30; 409 unit = 'G'; 410 if (diskSize < divisor) { 411 divisor = 1UL << 20; 412 unit = 'M'; 413 } 414 } 415 416 double size = double((10 * diskSize + divisor - 1) / divisor); 417 // %g in the kernel does not support precision... 418 419 snprintf(fName, sizeof(fName), "%g %cB Btrfs Volume", 420 size / 10, unit); 421 } 422 423 return B_OK; 424 } 425 426 427 status_t 428 Volume::Unmount() 429 { 430 TRACE("Volume::Unmount()\n"); 431 delete fExtentTree; 432 delete fChecksumTree; 433 delete fFSTree; 434 delete fDevTree; 435 fExtentTree = NULL; 436 fChecksumTree = NULL; 437 fFSTree = NULL; 438 fDevTree = NULL; 439 440 TRACE("Volume::Unmount(): Putting root node\n"); 441 put_vnode(fFSVolume, RootNode()->ID()); 442 TRACE("Volume::Unmount(): Deleting the block cache\n"); 443 block_cache_delete(fBlockCache, !IsReadOnly()); 444 TRACE("Volume::Unmount(): Closing device\n"); 445 close(fDevice); 446 447 TRACE("Volume::Unmount(): Done\n"); 448 return B_OK; 449 } 450 451 452 status_t 453 Volume::LoadSuperBlock() 454 { 455 CachedBlock cached(this); 456 const uint8* block = cached.SetTo(BTRFS_SUPER_BLOCK_OFFSET / fBlockSize); 457 458 if (block == NULL) 459 return B_IO_ERROR; 460 461 memcpy(&fSuperBlock, block + BTRFS_SUPER_BLOCK_OFFSET % fBlockSize, 462 sizeof(fSuperBlock)); 463 464 return B_OK; 465 } 466 467 468 status_t 469 Volume::FindBlock(off_t logical, fsblock_t& physicalBlock) 470 { 471 off_t physical; 472 status_t status = FindBlock(logical, physical); 473 if (status != B_OK) 474 return status; 475 physicalBlock = physical / fBlockSize; 476 return B_OK; 477 } 478 479 480 status_t 481 Volume::FindBlock(off_t logical, off_t& physical) 482 { 483 if (fChunkTree == NULL 484 || (logical >= (off_t)fChunk->Offset() 485 && logical < (off_t)fChunk->End())) { 486 // try with fChunk 487 return fChunk->FindBlock(logical, physical); 488 } 489 490 struct btrfs_key search_key; 491 search_key.SetOffset(logical); 492 search_key.SetType(BTRFS_KEY_TYPE_CHUNK_ITEM); 493 search_key.SetObjectID(BTRFS_OBJECT_ID_CHUNK_TREE); 494 struct btrfs_chunk* chunk; 495 size_t chunk_length; 496 status_t status = fChunkTree->FindPrevious(search_key, (void**)&chunk, 497 &chunk_length); 498 if (status != B_OK) 499 return status; 500 501 Chunk _chunk(chunk, search_key.Offset()); 502 free(chunk); 503 status = _chunk.FindBlock(logical, physical); 504 if (status != B_OK) 505 return status; 506 TRACE("Volume::FindBlock(): logical: %" B_PRIdOFF ", physical: %" B_PRIdOFF 507 "\n", logical, physical); 508 return B_OK; 509 } 510 511 512 // #pragma mark - Disk scanning and initialization 513 514 515 /*static*/ status_t 516 Volume::Identify(int fd, btrfs_super_block* superBlock) 517 { 518 if (read_pos(fd, BTRFS_SUPER_BLOCK_OFFSET, superBlock, 519 sizeof(btrfs_super_block)) != sizeof(btrfs_super_block)) 520 return B_IO_ERROR; 521 522 if (!superBlock->IsValid()) { 523 ERROR("invalid superblock!\n"); 524 return B_BAD_VALUE; 525 } 526 527 return B_OK; 528 } 529 530