1 /* 2 * openfs.c --- open an ext2 filesystem 3 * 4 * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o. 5 * 6 * %Begin-Header% 7 * This file may be redistributed under the terms of the GNU Library 8 * General Public License, version 2. 9 * %End-Header% 10 */ 11 12 #include "config.h" 13 #include <stdio.h> 14 #include <string.h> 15 #if HAVE_UNISTD_H 16 #include <unistd.h> 17 #endif 18 #include <fcntl.h> 19 #include <time.h> 20 #if HAVE_SYS_STAT_H 21 #include <sys/stat.h> 22 #endif 23 #if HAVE_SYS_TYPES_H 24 #include <sys/types.h> 25 #endif 26 #ifdef HAVE_ERRNO_H 27 #include <errno.h> 28 #endif 29 30 #include "ext2_fs.h" 31 32 33 #include "ext2fs.h" 34 #include "e2image.h" 35 36 blk64_t ext2fs_descriptor_block_loc2(ext2_filsys fs, blk64_t group_block, 37 dgrp_t i) 38 { 39 int bg; 40 int has_super = 0, group_zero_adjust = 0; 41 blk64_t ret_blk; 42 43 /* 44 * On a bigalloc FS with 1K blocks, block 0 is reserved for non-ext4 45 * stuff, so adjust for that if we're being asked for group 0. 46 */ 47 if (i == 0 && fs->blocksize == 1024 && EXT2FS_CLUSTER_RATIO(fs) > 1) 48 group_zero_adjust = 1; 49 50 if (!ext2fs_has_feature_meta_bg(fs->super) || 51 (i < fs->super->s_first_meta_bg)) 52 return group_block + i + 1 + group_zero_adjust; 53 54 bg = EXT2_DESC_PER_BLOCK(fs->super) * i; 55 if (ext2fs_bg_has_super(fs, bg)) 56 has_super = 1; 57 ret_blk = ext2fs_group_first_block2(fs, bg); 58 /* 59 * If group_block is not the normal value, we're trying to use 60 * the backup group descriptors and superblock --- so use the 61 * alternate location of the second block group in the 62 * metablock group. Ideally we should be testing each bg 63 * descriptor block individually for correctness, but we don't 64 * have the infrastructure in place to do that. 65 */ 66 if (group_block != fs->super->s_first_data_block && 67 ((ret_blk + has_super + fs->super->s_blocks_per_group) < 68 ext2fs_blocks_count(fs->super))) { 69 ret_blk += fs->super->s_blocks_per_group; 70 71 /* 72 * If we're going to jump forward a block group, make sure 73 * that we adjust has_super to account for the next group's 74 * backup superblock (or lack thereof). 75 */ 76 if (ext2fs_bg_has_super(fs, bg + 1)) 77 has_super = 1; 78 else 79 has_super = 0; 80 } 81 return ret_blk + has_super + group_zero_adjust; 82 } 83 84 blk_t ext2fs_descriptor_block_loc(ext2_filsys fs, blk_t group_block, dgrp_t i) 85 { 86 return ext2fs_descriptor_block_loc2(fs, group_block, i); 87 } 88 89 errcode_t ext2fs_open(const char *name, int flags, int superblock, 90 unsigned int block_size, io_manager manager, 91 ext2_filsys *ret_fs) 92 { 93 return ext2fs_open2(name, 0, flags, superblock, block_size, 94 manager, ret_fs); 95 } 96 97 /* 98 * Note: if superblock is non-zero, block-size must also be non-zero. 99 * Superblock and block_size can be zero to use the default size. 100 * 101 * Valid flags for ext2fs_open() 102 * 103 * EXT2_FLAG_RW - Open the filesystem for read/write. 104 * EXT2_FLAG_FORCE - Open the filesystem even if some of the 105 * features aren't supported. 106 * EXT2_FLAG_JOURNAL_DEV_OK - Open an ext3 journal device 107 * EXT2_FLAG_SKIP_MMP - Open without multi-mount protection check. 108 * EXT2_FLAG_64BITS - Allow 64-bit bitfields (needed for large 109 * filesystems) 110 */ 111 errcode_t ext2fs_open2(const char *name, const char *io_options, 112 int flags, int superblock, 113 unsigned int block_size, io_manager manager, 114 ext2_filsys *ret_fs) 115 { 116 ext2_filsys fs; 117 errcode_t retval; 118 unsigned long i, first_meta_bg; 119 __u32 features; 120 unsigned int blocks_per_group, io_flags; 121 blk64_t group_block, blk; 122 char *dest, *cp; 123 int group_zero_adjust = 0; 124 #ifdef WORDS_BIGENDIAN 125 unsigned int groups_per_block; 126 struct ext2_group_desc *gdp; 127 int j; 128 #endif 129 130 EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER); 131 132 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs); 133 if (retval) 134 return retval; 135 136 memset(fs, 0, sizeof(struct struct_ext2_filsys)); 137 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS; 138 fs->flags = flags; 139 /* don't overwrite sb backups unless flag is explicitly cleared */ 140 fs->flags |= EXT2_FLAG_MASTER_SB_ONLY; 141 fs->umask = 022; 142 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name); 143 if (retval) 144 goto cleanup; 145 strcpy(fs->device_name, name); 146 cp = strchr(fs->device_name, '?'); 147 if (!io_options && cp) { 148 *cp++ = 0; 149 io_options = cp; 150 } 151 152 io_flags = 0; 153 if (flags & EXT2_FLAG_RW) 154 io_flags |= IO_FLAG_RW; 155 if (flags & EXT2_FLAG_EXCLUSIVE) 156 io_flags |= IO_FLAG_EXCLUSIVE; 157 if (flags & EXT2_FLAG_DIRECT_IO) 158 io_flags |= IO_FLAG_DIRECT_IO; 159 retval = manager->open(fs->device_name, io_flags, &fs->io); 160 if (retval) 161 goto cleanup; 162 if (io_options && 163 (retval = io_channel_set_options(fs->io, io_options))) 164 goto cleanup; 165 fs->image_io = fs->io; 166 fs->io->app_data = fs; 167 retval = io_channel_alloc_buf(fs->io, -SUPERBLOCK_SIZE, &fs->super); 168 if (retval) 169 goto cleanup; 170 if (flags & EXT2_FLAG_IMAGE_FILE) { 171 retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr), 172 &fs->image_header); 173 if (retval) 174 goto cleanup; 175 retval = io_channel_read_blk(fs->io, 0, 176 -(int)sizeof(struct ext2_image_hdr), 177 fs->image_header); 178 if (retval) 179 goto cleanup; 180 if (fs->image_header->magic_number != EXT2_ET_MAGIC_E2IMAGE) 181 return EXT2_ET_MAGIC_E2IMAGE; 182 superblock = 1; 183 block_size = fs->image_header->fs_blocksize; 184 } 185 186 /* 187 * If the user specifies a specific block # for the 188 * superblock, then he/she must also specify the block size! 189 * Otherwise, read the master superblock located at offset 190 * SUPERBLOCK_OFFSET from the start of the partition. 191 * 192 * Note: we only save a backup copy of the superblock if we 193 * are reading the superblock from the primary superblock location. 194 */ 195 if (superblock) { 196 if (!block_size) { 197 retval = EXT2_ET_INVALID_ARGUMENT; 198 goto cleanup; 199 } 200 io_channel_set_blksize(fs->io, block_size); 201 group_block = superblock; 202 fs->orig_super = 0; 203 } else { 204 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET); 205 superblock = 1; 206 group_block = 0; 207 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super); 208 if (retval) 209 goto cleanup; 210 } 211 retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE, 212 fs->super); 213 if (retval) 214 goto cleanup; 215 if (fs->orig_super) 216 memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE); 217 218 if (!(fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS)) { 219 retval = 0; 220 if (!ext2fs_verify_csum_type(fs, fs->super)) 221 retval = EXT2_ET_UNKNOWN_CSUM; 222 if (!ext2fs_superblock_csum_verify(fs, fs->super)) 223 retval = EXT2_ET_SB_CSUM_INVALID; 224 } 225 226 #ifdef WORDS_BIGENDIAN 227 fs->flags |= EXT2_FLAG_SWAP_BYTES; 228 ext2fs_swap_super(fs->super); 229 #else 230 if (fs->flags & EXT2_FLAG_SWAP_BYTES) { 231 retval = EXT2_ET_UNIMPLEMENTED; 232 goto cleanup; 233 } 234 #endif 235 236 if (fs->super->s_magic != EXT2_SUPER_MAGIC) 237 retval = EXT2_ET_BAD_MAGIC; 238 if (retval) 239 goto cleanup; 240 241 if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) { 242 retval = EXT2_ET_REV_TOO_HIGH; 243 goto cleanup; 244 } 245 246 /* 247 * Check for feature set incompatibility 248 */ 249 if (!(flags & EXT2_FLAG_FORCE)) { 250 features = fs->super->s_feature_incompat; 251 #ifdef EXT2_LIB_SOFTSUPP_INCOMPAT 252 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES) 253 features &= ~EXT2_LIB_SOFTSUPP_INCOMPAT; 254 #endif 255 if (features & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) { 256 retval = EXT2_ET_UNSUPP_FEATURE; 257 goto cleanup; 258 } 259 260 features = fs->super->s_feature_ro_compat; 261 #ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT 262 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES) 263 features &= ~EXT2_LIB_SOFTSUPP_RO_COMPAT; 264 #endif 265 if ((flags & EXT2_FLAG_RW) && 266 (features & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) { 267 retval = EXT2_ET_RO_UNSUPP_FEATURE; 268 goto cleanup; 269 } 270 271 if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) && 272 ext2fs_has_feature_journal_dev(fs->super)) { 273 retval = EXT2_ET_UNSUPP_FEATURE; 274 goto cleanup; 275 } 276 } 277 278 if ((fs->super->s_log_block_size + EXT2_MIN_BLOCK_LOG_SIZE) > 279 EXT2_MAX_BLOCK_LOG_SIZE) { 280 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 281 goto cleanup; 282 } 283 284 /* 285 * bigalloc requires cluster-aware bitfield operations, which at the 286 * moment means we need EXT2_FLAG_64BITS. 287 */ 288 if (ext2fs_has_feature_bigalloc(fs->super) && 289 !(flags & EXT2_FLAG_64BITS)) { 290 retval = EXT2_ET_CANT_USE_LEGACY_BITMAPS; 291 goto cleanup; 292 } 293 294 if (!ext2fs_has_feature_bigalloc(fs->super) && 295 (fs->super->s_log_block_size != fs->super->s_log_cluster_size)) { 296 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 297 goto cleanup; 298 } 299 fs->fragsize = fs->blocksize = EXT2_BLOCK_SIZE(fs->super); 300 if (EXT2_INODE_SIZE(fs->super) < EXT2_GOOD_OLD_INODE_SIZE) { 301 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 302 goto cleanup; 303 } 304 305 /* Enforce the block group descriptor size */ 306 if (ext2fs_has_feature_64bit(fs->super)) { 307 if (fs->super->s_desc_size < EXT2_MIN_DESC_SIZE_64BIT) { 308 retval = EXT2_ET_BAD_DESC_SIZE; 309 goto cleanup; 310 } 311 } else { 312 if (fs->super->s_desc_size && 313 fs->super->s_desc_size != EXT2_MIN_DESC_SIZE) { 314 retval = EXT2_ET_BAD_DESC_SIZE; 315 goto cleanup; 316 } 317 } 318 319 fs->cluster_ratio_bits = fs->super->s_log_cluster_size - 320 fs->super->s_log_block_size; 321 if (EXT2_BLOCKS_PER_GROUP(fs->super) != 322 EXT2_CLUSTERS_PER_GROUP(fs->super) << fs->cluster_ratio_bits) { 323 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 324 goto cleanup; 325 } 326 fs->inode_blocks_per_group = ((EXT2_INODES_PER_GROUP(fs->super) * 327 EXT2_INODE_SIZE(fs->super) + 328 EXT2_BLOCK_SIZE(fs->super) - 1) / 329 EXT2_BLOCK_SIZE(fs->super)); 330 if (block_size) { 331 if (block_size != fs->blocksize) { 332 retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE; 333 goto cleanup; 334 } 335 } 336 /* 337 * Set the blocksize to the filesystem's blocksize. 338 */ 339 io_channel_set_blksize(fs->io, fs->blocksize); 340 341 /* 342 * If this is an external journal device, don't try to read 343 * the group descriptors, because they're not there. 344 */ 345 if (ext2fs_has_feature_journal_dev(fs->super)) { 346 fs->group_desc_count = 0; 347 *ret_fs = fs; 348 return 0; 349 } 350 351 if (EXT2_INODES_PER_GROUP(fs->super) == 0) { 352 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 353 goto cleanup; 354 } 355 /* Precompute the FS UUID to seed other checksums */ 356 ext2fs_init_csum_seed(fs); 357 358 /* 359 * Read group descriptors 360 */ 361 blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super); 362 if (blocks_per_group == 0 || 363 blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) || 364 fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super) || 365 EXT2_DESC_PER_BLOCK(fs->super) == 0 || 366 fs->super->s_first_data_block >= ext2fs_blocks_count(fs->super)) { 367 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 368 goto cleanup; 369 } 370 fs->group_desc_count = ext2fs_div64_ceil(ext2fs_blocks_count(fs->super) - 371 fs->super->s_first_data_block, 372 blocks_per_group); 373 if (fs->group_desc_count * EXT2_INODES_PER_GROUP(fs->super) != 374 fs->super->s_inodes_count) { 375 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 376 goto cleanup; 377 } 378 fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count, 379 EXT2_DESC_PER_BLOCK(fs->super)); 380 retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize, 381 &fs->group_desc); 382 if (retval) 383 goto cleanup; 384 if (!group_block) 385 group_block = fs->super->s_first_data_block; 386 /* 387 * On a FS with a 1K blocksize, block 0 is reserved for bootloaders 388 * so we must increment block numbers to any group 0 items. 389 * 390 * However, we cannot touch group_block directly because in the meta_bg 391 * case, the ext2fs_descriptor_block_loc2() function will interpret 392 * group_block != s_first_data_block to mean that we want to access the 393 * backup group descriptors. This is not what we want if the caller 394 * set superblock == 0 (i.e. auto-detect the superblock), which is 395 * what's going on here. 396 */ 397 if (group_block == 0 && fs->blocksize == 1024) 398 group_zero_adjust = 1; 399 dest = (char *) fs->group_desc; 400 #ifdef WORDS_BIGENDIAN 401 groups_per_block = EXT2_DESC_PER_BLOCK(fs->super); 402 #endif 403 if (ext2fs_has_feature_meta_bg(fs->super)) { 404 first_meta_bg = fs->super->s_first_meta_bg; 405 if (first_meta_bg > fs->desc_blocks) 406 first_meta_bg = fs->desc_blocks; 407 } else 408 first_meta_bg = fs->desc_blocks; 409 if (first_meta_bg) { 410 retval = io_channel_read_blk(fs->io, group_block + 411 group_zero_adjust + 1, 412 first_meta_bg, dest); 413 if (retval) 414 goto cleanup; 415 #ifdef WORDS_BIGENDIAN 416 gdp = (struct ext2_group_desc *) dest; 417 for (j=0; j < groups_per_block*first_meta_bg; j++) { 418 gdp = ext2fs_group_desc(fs, fs->group_desc, j); 419 ext2fs_swap_group_desc2(fs, gdp); 420 } 421 #endif 422 dest += fs->blocksize*first_meta_bg; 423 } 424 for (i=first_meta_bg ; i < fs->desc_blocks; i++) { 425 blk = ext2fs_descriptor_block_loc2(fs, group_block, i); 426 retval = io_channel_read_blk64(fs->io, blk, 1, dest); 427 if (retval) 428 goto cleanup; 429 #ifdef WORDS_BIGENDIAN 430 for (j=0; j < groups_per_block; j++) { 431 gdp = ext2fs_group_desc(fs, fs->group_desc, 432 i * groups_per_block + j); 433 ext2fs_swap_group_desc2(fs, gdp); 434 } 435 #endif 436 dest += fs->blocksize; 437 } 438 439 fs->stride = fs->super->s_raid_stride; 440 441 /* 442 * If recovery is from backup superblock, Clear _UNININT flags & 443 * reset bg_itable_unused to zero 444 */ 445 if (superblock > 1 && ext2fs_has_group_desc_csum(fs)) { 446 dgrp_t group; 447 448 for (group = 0; group < fs->group_desc_count; group++) { 449 ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT); 450 ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT); 451 ext2fs_bg_itable_unused_set(fs, group, 0); 452 /* The checksum will be reset later, but fix it here 453 * anyway to avoid printing a lot of spurious errors. */ 454 ext2fs_group_desc_csum_set(fs, group); 455 } 456 if (fs->flags & EXT2_FLAG_RW) 457 ext2fs_mark_super_dirty(fs); 458 } 459 460 if (ext2fs_has_feature_mmp(fs->super) && 461 !(flags & EXT2_FLAG_SKIP_MMP) && 462 (flags & (EXT2_FLAG_RW | EXT2_FLAG_EXCLUSIVE))) { 463 retval = ext2fs_mmp_start(fs); 464 if (retval) { 465 fs->flags |= EXT2_FLAG_SKIP_MMP; /* just do cleanup */ 466 ext2fs_mmp_stop(fs); 467 goto cleanup; 468 } 469 } 470 471 fs->flags &= ~EXT2_FLAG_NOFREE_ON_ERROR; 472 *ret_fs = fs; 473 474 return 0; 475 cleanup: 476 if (!(flags & EXT2_FLAG_NOFREE_ON_ERROR)) { 477 ext2fs_free(fs); 478 fs = NULL; 479 } 480 *ret_fs = fs; 481 return retval; 482 } 483 484 /* 485 * Set/get the filesystem data I/O channel. 486 * 487 * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true. 488 */ 489 errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io) 490 { 491 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) 492 return EXT2_ET_NOT_IMAGE_FILE; 493 if (old_io) { 494 *old_io = (fs->image_io == fs->io) ? 0 : fs->io; 495 } 496 return 0; 497 } 498 499 errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io) 500 { 501 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) 502 return EXT2_ET_NOT_IMAGE_FILE; 503 fs->io = new_io ? new_io : fs->image_io; 504 return 0; 505 } 506 507 errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io) 508 { 509 errcode_t err; 510 511 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) 512 return EXT2_ET_NOT_IMAGE_FILE; 513 err = io_channel_set_blksize(new_io, fs->blocksize); 514 if (err) 515 return err; 516 if ((new_io == fs->image_io) || (new_io == fs->io)) 517 return 0; 518 if ((fs->image_io != fs->io) && 519 fs->image_io) 520 io_channel_close(fs->image_io); 521 if (fs->io) 522 io_channel_close(fs->io); 523 fs->io = fs->image_io = new_io; 524 fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW | 525 EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY; 526 fs->flags &= ~EXT2_FLAG_IMAGE_FILE; 527 return 0; 528 } 529
