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 13 #include <errno.h> 14 #include <new> 15 #include <stdio.h> 16 #include <stdlib.h> 17 #include <string.h> 18 19 #include <fs_cache.h> 20 #include <fs_volume.h> 21 22 #include <util/AutoLock.h> 23 24 #include "BPlusTree.h" 25 #include "CachedBlock.h" 26 #include "Chunk.h" 27 #include "Inode.h" 28 29 30 //#define TRACE_BTRFS 31 #ifdef TRACE_BTRFS 32 # define TRACE(x...) dprintf("\33[34mbtrfs:\33[0m " x) 33 #else 34 # define TRACE(x...) ; 35 #endif 36 # define ERROR(x...) dprintf("\33[34mbtrfs:\33[0m " x) 37 38 39 class DeviceOpener { 40 public: 41 DeviceOpener(int fd, int mode); 42 DeviceOpener(const char* device, int mode); 43 ~DeviceOpener(); 44 45 int Open(const char* device, int mode); 46 int Open(int fd, int mode); 47 void* InitCache(off_t numBlocks, uint32 blockSize); 48 void RemoveCache(bool allowWrites); 49 50 void Keep(); 51 52 int Device() const { return fDevice; } 53 int Mode() const { return fMode; } 54 bool IsReadOnly() const 55 { return _IsReadOnly(fMode); } 56 57 status_t GetSize(off_t* _size, uint32* _blockSize = NULL); 58 59 private: 60 static bool _IsReadOnly(int mode) 61 { return (mode & O_RWMASK) == O_RDONLY;} 62 static bool _IsReadWrite(int mode) 63 { return (mode & O_RWMASK) == O_RDWR;} 64 65 int fDevice; 66 int fMode; 67 void* fBlockCache; 68 }; 69 70 71 DeviceOpener::DeviceOpener(const char* device, int mode) 72 : 73 fBlockCache(NULL) 74 { 75 Open(device, mode); 76 } 77 78 79 DeviceOpener::DeviceOpener(int fd, int mode) 80 : 81 fBlockCache(NULL) 82 { 83 Open(fd, mode); 84 } 85 86 87 DeviceOpener::~DeviceOpener() 88 { 89 if (fDevice >= 0) { 90 RemoveCache(false); 91 close(fDevice); 92 } 93 } 94 95 96 int 97 DeviceOpener::Open(const char* device, int mode) 98 { 99 fDevice = open(device, mode | O_NOCACHE); 100 if (fDevice < 0) 101 fDevice = errno; 102 103 if (fDevice < 0 && _IsReadWrite(mode)) { 104 // try again to open read-only (don't rely on a specific error code) 105 return Open(device, O_RDONLY | O_NOCACHE); 106 } 107 108 if (fDevice >= 0) { 109 // opening succeeded 110 fMode = mode; 111 if (_IsReadWrite(mode)) { 112 // check out if the device really allows for read/write access 113 device_geometry geometry; 114 if (!ioctl(fDevice, B_GET_GEOMETRY, &geometry)) { 115 if (geometry.read_only) { 116 // reopen device read-only 117 close(fDevice); 118 return Open(device, O_RDONLY | O_NOCACHE); 119 } 120 } 121 } 122 } 123 124 return fDevice; 125 } 126 127 128 int 129 DeviceOpener::Open(int fd, int mode) 130 { 131 fDevice = dup(fd); 132 if (fDevice < 0) 133 return errno; 134 135 fMode = mode; 136 137 return fDevice; 138 } 139 140 141 void* 142 DeviceOpener::InitCache(off_t numBlocks, uint32 blockSize) 143 { 144 return fBlockCache = block_cache_create(fDevice, numBlocks, blockSize, 145 IsReadOnly()); 146 } 147 148 149 void 150 DeviceOpener::RemoveCache(bool allowWrites) 151 { 152 if (fBlockCache == NULL) 153 return; 154 155 block_cache_delete(fBlockCache, allowWrites); 156 fBlockCache = NULL; 157 } 158 159 160 void 161 DeviceOpener::Keep() 162 { 163 fDevice = -1; 164 } 165 166 167 /*! Returns the size of the device in bytes. It uses B_GET_GEOMETRY 168 to compute the size, or fstat() if that failed. 169 */ 170 status_t 171 DeviceOpener::GetSize(off_t* _size, uint32* _blockSize) 172 { 173 device_geometry geometry; 174 if (ioctl(fDevice, B_GET_GEOMETRY, &geometry) < 0) { 175 // maybe it's just a file 176 struct stat stat; 177 if (fstat(fDevice, &stat) < 0) 178 return B_ERROR; 179 180 if (_size) 181 *_size = stat.st_size; 182 if (_blockSize) // that shouldn't cause us any problems 183 *_blockSize = 512; 184 185 return B_OK; 186 } 187 188 if (_size) { 189 *_size = 1ULL * geometry.head_count * geometry.cylinder_count 190 * geometry.sectors_per_track * geometry.bytes_per_sector; 191 } 192 if (_blockSize) 193 *_blockSize = geometry.bytes_per_sector; 194 195 return B_OK; 196 } 197 198 199 // #pragma mark - 200 201 202 bool 203 btrfs_super_block::IsValid() 204 { 205 // TODO: check some more values! 206 if (strncmp(magic, BTRFS_SUPER_BLOCK_MAGIC, sizeof(magic)) != 0) 207 return false; 208 209 return true; 210 } 211 212 213 // #pragma mark - 214 215 216 Volume::Volume(fs_volume* volume) 217 : 218 fFSVolume(volume), 219 fFlags(0), 220 fChunk(NULL), 221 fChunkTree(NULL) 222 { 223 mutex_init(&fLock, "btrfs volume"); 224 } 225 226 227 Volume::~Volume() 228 { 229 TRACE("Volume destructor.\n"); 230 } 231 232 233 bool 234 Volume::IsValidSuperBlock() 235 { 236 return fSuperBlock.IsValid(); 237 } 238 239 240 const char* 241 Volume::Name() const 242 { 243 if (fSuperBlock.label[0]) 244 return fSuperBlock.label; 245 246 return fName; 247 } 248 249 250 status_t 251 Volume::Mount(const char* deviceName, uint32 flags) 252 { 253 flags |= B_MOUNT_READ_ONLY; 254 // we only support read-only for now 255 256 if ((flags & B_MOUNT_READ_ONLY) != 0) { 257 TRACE("Volume::Mount(): Read only\n"); 258 } else { 259 TRACE("Volume::Mount(): Read write\n"); 260 } 261 262 DeviceOpener opener(deviceName, (flags & B_MOUNT_READ_ONLY) != 0 263 ? O_RDONLY : O_RDWR); 264 fDevice = opener.Device(); 265 if (fDevice < B_OK) { 266 ERROR("Volume::Mount(): couldn't open device\n"); 267 return fDevice; 268 } 269 270 if (opener.IsReadOnly()) 271 fFlags |= VOLUME_READ_ONLY; 272 273 // read the superblock 274 status_t status = Identify(fDevice, &fSuperBlock); 275 if (status != B_OK) { 276 ERROR("Volume::Mount(): Identify() failed\n"); 277 return status; 278 } 279 280 fBlockSize = fSuperBlock.BlockSize(); 281 TRACE("block size %ld\n", fBlockSize); 282 283 uint8* start = (uint8*)&fSuperBlock.system_chunk_array[0]; 284 uint8* end = (uint8*)&fSuperBlock.system_chunk_array[2048]; 285 while (start < end) { 286 struct btrfs_key* key = (struct btrfs_key*)start; 287 TRACE("system_chunk_array object_id 0x%llx offset 0x%llx type 0x%x\n", 288 key->ObjectID(), key->Offset(), key->Type()); 289 if (key->Type() != BTRFS_KEY_TYPE_CHUNK_ITEM) { 290 break; 291 } 292 293 struct btrfs_chunk* chunk = (struct btrfs_chunk*)(key + 1); 294 fChunk = new(std::nothrow) Chunk(chunk, key->Offset()); 295 if (fChunk == NULL) 296 return B_ERROR; 297 start += sizeof(struct btrfs_key) + fChunk->Size(); 298 } 299 300 TRACE("Volume::Mount() generation: %lld\n", fSuperBlock.Generation()); 301 fsblock_t physical = 0; 302 FindBlock(fSuperBlock.Root(), physical); 303 TRACE("Volume::Mount() root: %lld (physical %lld)\n", 304 fSuperBlock.Root(), physical); 305 FindBlock(fSuperBlock.ChunkRoot(), physical); 306 TRACE("Volume::Mount() chunk_root: %lld (physical %lld)\n", 307 fSuperBlock.ChunkRoot(), physical); 308 FindBlock(fSuperBlock.LogRoot(), physical); 309 TRACE("Volume::Mount() log_root: %lld (physical %lld)\n", 310 fSuperBlock.LogRoot(), physical); 311 312 // check if the device size is large enough to hold the file system 313 off_t diskSize; 314 status = opener.GetSize(&diskSize); 315 if (status != B_OK) 316 return status; 317 if (diskSize < (off_t)fSuperBlock.TotalSize()) 318 return B_BAD_VALUE; 319 320 fBlockCache = opener.InitCache(fSuperBlock.TotalSize() / fBlockSize, 321 fBlockSize); 322 if (fBlockCache == NULL) 323 return B_ERROR; 324 325 TRACE("Volume::Mount(): Initialized block cache: %p\n", fBlockCache); 326 327 fChunkTree = new(std::nothrow) BPlusTree(this, fSuperBlock.ChunkRoot()); 328 if (fChunkTree == NULL) 329 return B_NO_MEMORY; 330 331 FindBlock(fSuperBlock.Root(), physical); 332 TRACE("Volume::Mount() root: %lld (physical %lld)\n", 333 fSuperBlock.Root(), physical); 334 FindBlock(fSuperBlock.ChunkRoot(), physical); 335 TRACE("Volume::Mount() chunk_root: %lld (physical %lld)\n", 336 fSuperBlock.ChunkRoot(), physical); 337 FindBlock(fSuperBlock.LogRoot(), physical); 338 TRACE("Volume::Mount() log_root: %lld (physical %lld)\n", 339 fSuperBlock.LogRoot(), physical); 340 341 fRootTree = new(std::nothrow) BPlusTree(this, fSuperBlock.Root()); 342 if (fRootTree == NULL) 343 return B_NO_MEMORY; 344 TRACE("Volume::Mount(): Searching extent root\n"); 345 struct btrfs_key search_key; 346 search_key.SetOffset(0); 347 search_key.SetType(BTRFS_KEY_TYPE_ROOT_ITEM); 348 search_key.SetObjectID(BTRFS_OBJECT_ID_EXTENT_TREE); 349 struct btrfs_root *root; 350 if (fRootTree->FindNext(search_key, (void**)&root) != B_OK) { 351 ERROR("Volume::Mount(): Couldn't find extent root\n"); 352 return B_ERROR; 353 } 354 TRACE("Volume::Mount(): Found extent root: %lld\n", root->BlockNum()); 355 fExtentTree = new(std::nothrow) BPlusTree(this, root->BlockNum()); 356 free(root); 357 if (fExtentTree == NULL) 358 return B_NO_MEMORY; 359 360 search_key.SetOffset(0); 361 search_key.SetObjectID(BTRFS_OBJECT_ID_FS_TREE); 362 if (fRootTree->FindNext(search_key, (void**)&root) != B_OK) { 363 ERROR("Volume::Mount(): Couldn't find fs root\n"); 364 return B_ERROR; 365 } 366 TRACE("Volume::Mount(): Found fs root: %lld\n", root->BlockNum()); 367 fFSTree = new(std::nothrow) BPlusTree(this, root->BlockNum()); 368 free(root); 369 if (fFSTree == NULL) 370 return B_NO_MEMORY; 371 372 search_key.SetOffset(0); 373 search_key.SetObjectID(BTRFS_OBJECT_ID_DEV_TREE); 374 if (fRootTree->FindNext(search_key, (void**)&root) != B_OK) { 375 ERROR("Volume::Mount(): Couldn't find dev root\n"); 376 return B_ERROR; 377 } 378 TRACE("Volume::Mount(): Found dev root: %lld\n", root->BlockNum()); 379 fDevTree = new(std::nothrow) BPlusTree(this, root->BlockNum()); 380 free(root); 381 if (fDevTree == NULL) 382 return B_NO_MEMORY; 383 384 search_key.SetOffset(0); 385 search_key.SetObjectID(BTRFS_OBJECT_ID_CHECKSUM_TREE); 386 if (fRootTree->FindNext(search_key, (void**)&root) != B_OK) { 387 ERROR("Volume::Mount(): Couldn't find checksum root\n"); 388 return B_ERROR; 389 } 390 TRACE("Volume::Mount(): Found checksum root: %lld\n", root->BlockNum()); 391 fChecksumTree = new(std::nothrow) BPlusTree(this, root->BlockNum()); 392 free(root); 393 if (fChecksumTree == NULL) 394 return B_NO_MEMORY; 395 396 // ready 397 status = get_vnode(fFSVolume, BTRFS_OBJECT_ID_CHUNK_TREE, 398 (void**)&fRootNode); 399 if (status != B_OK) { 400 ERROR("could not create root node: get_vnode() failed!\n"); 401 return status; 402 } 403 404 TRACE("Volume::Mount(): Found root node: %lld (%s)\n", fRootNode->ID(), 405 strerror(fRootNode->InitCheck())); 406 407 // all went fine 408 opener.Keep(); 409 410 if (!fSuperBlock.label[0]) { 411 // generate a more or less descriptive volume name 412 off_t divisor = 1ULL << 40; 413 char unit = 'T'; 414 if (diskSize < divisor) { 415 divisor = 1UL << 30; 416 unit = 'G'; 417 if (diskSize < divisor) { 418 divisor = 1UL << 20; 419 unit = 'M'; 420 } 421 } 422 423 double size = double((10 * diskSize + divisor - 1) / divisor); 424 // %g in the kernel does not support precision... 425 426 snprintf(fName, sizeof(fName), "%g %cB Btrfs Volume", 427 size / 10, unit); 428 } 429 430 return B_OK; 431 } 432 433 434 status_t 435 Volume::Unmount() 436 { 437 TRACE("Volume::Unmount()\n"); 438 delete fExtentTree; 439 delete fChecksumTree; 440 delete fFSTree; 441 delete fDevTree; 442 fExtentTree = NULL; 443 fChecksumTree = NULL; 444 fFSTree = NULL; 445 fDevTree = NULL; 446 447 TRACE("Volume::Unmount(): Putting root node\n"); 448 put_vnode(fFSVolume, RootNode()->ID()); 449 TRACE("Volume::Unmount(): Deleting the block cache\n"); 450 block_cache_delete(fBlockCache, !IsReadOnly()); 451 TRACE("Volume::Unmount(): Closing device\n"); 452 close(fDevice); 453 454 TRACE("Volume::Unmount(): Done\n"); 455 return B_OK; 456 } 457 458 459 status_t 460 Volume::LoadSuperBlock() 461 { 462 CachedBlock cached(this); 463 const uint8* block = cached.SetTo(BTRFS_SUPER_BLOCK_OFFSET / fBlockSize); 464 465 if (block == NULL) 466 return B_IO_ERROR; 467 468 memcpy(&fSuperBlock, block + BTRFS_SUPER_BLOCK_OFFSET % fBlockSize, 469 sizeof(fSuperBlock)); 470 471 return B_OK; 472 } 473 474 475 status_t 476 Volume::FindBlock(off_t logical, fsblock_t &physicalBlock) 477 { 478 off_t physical; 479 status_t status = FindBlock(logical, physical); 480 if (status != B_OK) 481 return status; 482 physicalBlock = physical / fBlockSize; 483 return B_OK; 484 } 485 486 487 status_t 488 Volume::FindBlock(off_t logical, off_t &physical) 489 { 490 if (fChunkTree == NULL 491 || (logical >= fChunk->Offset() && logical < fChunk->End())) { 492 // try with fChunk 493 return fChunk->FindBlock(logical, physical); 494 } 495 496 struct btrfs_key search_key; 497 search_key.SetOffset(logical); 498 search_key.SetType(BTRFS_KEY_TYPE_CHUNK_ITEM); 499 search_key.SetObjectID(BTRFS_OBJECT_ID_CHUNK_TREE); 500 struct btrfs_chunk *chunk; 501 size_t chunk_length; 502 status_t status = fChunkTree->FindPrevious(search_key, (void**)&chunk, 503 &chunk_length); 504 if (status != B_OK) 505 return status; 506 507 Chunk _chunk(chunk, search_key.Offset()); 508 free(chunk); 509 status = _chunk.FindBlock(logical, physical); 510 if (status != B_OK) 511 return status; 512 TRACE("Volume::FindBlock(): logical: %lld, physical: %lld\n", logical, 513 physical); 514 return B_OK; 515 } 516 517 518 // #pragma mark - Disk scanning and initialization 519 520 521 /*static*/ status_t 522 Volume::Identify(int fd, btrfs_super_block* superBlock) 523 { 524 if (read_pos(fd, BTRFS_SUPER_BLOCK_OFFSET, superBlock, 525 sizeof(btrfs_super_block)) != sizeof(btrfs_super_block)) 526 return B_IO_ERROR; 527 528 if (!superBlock->IsValid()) { 529 ERROR("invalid superblock!\n"); 530 return B_BAD_VALUE; 531 } 532 533 return B_OK; 534 } 535 536