openfs.c revision 51663e0d2aa2958b5ef590299b2018a2ae01d256
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 36blk64_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 84blk_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 89errcode_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 */ 111errcode_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 char *time_env; 130 131 EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER); 132 133 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs); 134 if (retval) 135 return retval; 136 137 memset(fs, 0, sizeof(struct struct_ext2_filsys)); 138 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS; 139 fs->flags = flags; 140 /* don't overwrite sb backups unless flag is explicitly cleared */ 141 fs->flags |= EXT2_FLAG_MASTER_SB_ONLY; 142 fs->umask = 022; 143 144 time_env = getenv("E2FSPROGS_FAKE_TIME"); 145 if (time_env) 146 fs->now = strtoul(time_env, NULL, 0); 147 148 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name); 149 if (retval) 150 goto cleanup; 151 strcpy(fs->device_name, name); 152 cp = strchr(fs->device_name, '?'); 153 if (!io_options && cp) { 154 *cp++ = 0; 155 io_options = cp; 156 } 157 158 io_flags = 0; 159 if (flags & EXT2_FLAG_RW) 160 io_flags |= IO_FLAG_RW; 161 if (flags & EXT2_FLAG_EXCLUSIVE) 162 io_flags |= IO_FLAG_EXCLUSIVE; 163 if (flags & EXT2_FLAG_DIRECT_IO) 164 io_flags |= IO_FLAG_DIRECT_IO; 165 retval = manager->open(fs->device_name, io_flags, &fs->io); 166 if (retval) 167 goto cleanup; 168 if (io_options && 169 (retval = io_channel_set_options(fs->io, io_options))) 170 goto cleanup; 171 fs->image_io = fs->io; 172 fs->io->app_data = fs; 173 retval = io_channel_alloc_buf(fs->io, -SUPERBLOCK_SIZE, &fs->super); 174 if (retval) 175 goto cleanup; 176 if (flags & EXT2_FLAG_IMAGE_FILE) { 177 retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr), 178 &fs->image_header); 179 if (retval) 180 goto cleanup; 181 retval = io_channel_read_blk(fs->io, 0, 182 -(int)sizeof(struct ext2_image_hdr), 183 fs->image_header); 184 if (retval) 185 goto cleanup; 186 if (fs->image_header->magic_number != EXT2_ET_MAGIC_E2IMAGE) 187 return EXT2_ET_MAGIC_E2IMAGE; 188 superblock = 1; 189 block_size = fs->image_header->fs_blocksize; 190 } 191 192 /* 193 * If the user specifies a specific block # for the 194 * superblock, then he/she must also specify the block size! 195 * Otherwise, read the master superblock located at offset 196 * SUPERBLOCK_OFFSET from the start of the partition. 197 * 198 * Note: we only save a backup copy of the superblock if we 199 * are reading the superblock from the primary superblock location. 200 */ 201 if (superblock) { 202 if (!block_size) { 203 retval = EXT2_ET_INVALID_ARGUMENT; 204 goto cleanup; 205 } 206 io_channel_set_blksize(fs->io, block_size); 207 group_block = superblock; 208 fs->orig_super = 0; 209 } else { 210 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET); 211 superblock = 1; 212 group_block = 0; 213 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super); 214 if (retval) 215 goto cleanup; 216 } 217 retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE, 218 fs->super); 219 if (retval) 220 goto cleanup; 221 if (fs->orig_super) 222 memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE); 223 224 if (!(fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS)) { 225 retval = 0; 226 if (!ext2fs_verify_csum_type(fs, fs->super)) 227 retval = EXT2_ET_UNKNOWN_CSUM; 228 if (!ext2fs_superblock_csum_verify(fs, fs->super)) 229 retval = EXT2_ET_SB_CSUM_INVALID; 230 } 231 232#ifdef WORDS_BIGENDIAN 233 fs->flags |= EXT2_FLAG_SWAP_BYTES; 234 ext2fs_swap_super(fs->super); 235#else 236 if (fs->flags & EXT2_FLAG_SWAP_BYTES) { 237 retval = EXT2_ET_UNIMPLEMENTED; 238 goto cleanup; 239 } 240#endif 241 242 if (fs->super->s_magic != EXT2_SUPER_MAGIC) 243 retval = EXT2_ET_BAD_MAGIC; 244 if (retval) 245 goto cleanup; 246 247 if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) { 248 retval = EXT2_ET_REV_TOO_HIGH; 249 goto cleanup; 250 } 251 252 /* 253 * Check for feature set incompatibility 254 */ 255 if (!(flags & EXT2_FLAG_FORCE)) { 256 features = fs->super->s_feature_incompat; 257#ifdef EXT2_LIB_SOFTSUPP_INCOMPAT 258 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES) 259 features &= ~EXT2_LIB_SOFTSUPP_INCOMPAT; 260#endif 261 if (features & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) { 262 retval = EXT2_ET_UNSUPP_FEATURE; 263 goto cleanup; 264 } 265 266 features = fs->super->s_feature_ro_compat; 267#ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT 268 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES) 269 features &= ~EXT2_LIB_SOFTSUPP_RO_COMPAT; 270#endif 271 if ((flags & EXT2_FLAG_RW) && 272 (features & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) { 273 retval = EXT2_ET_RO_UNSUPP_FEATURE; 274 goto cleanup; 275 } 276 277 if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) && 278 ext2fs_has_feature_journal_dev(fs->super)) { 279 retval = EXT2_ET_UNSUPP_FEATURE; 280 goto cleanup; 281 } 282 } 283 284 if ((fs->super->s_log_block_size + EXT2_MIN_BLOCK_LOG_SIZE) > 285 EXT2_MAX_BLOCK_LOG_SIZE) { 286 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 287 goto cleanup; 288 } 289 290 /* 291 * bigalloc requires cluster-aware bitfield operations, which at the 292 * moment means we need EXT2_FLAG_64BITS. 293 */ 294 if (ext2fs_has_feature_bigalloc(fs->super) && 295 !(flags & EXT2_FLAG_64BITS)) { 296 retval = EXT2_ET_CANT_USE_LEGACY_BITMAPS; 297 goto cleanup; 298 } 299 300 if (!ext2fs_has_feature_bigalloc(fs->super) && 301 (fs->super->s_log_block_size != fs->super->s_log_cluster_size)) { 302 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 303 goto cleanup; 304 } 305 fs->fragsize = fs->blocksize = EXT2_BLOCK_SIZE(fs->super); 306 if (EXT2_INODE_SIZE(fs->super) < EXT2_GOOD_OLD_INODE_SIZE) { 307 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 308 goto cleanup; 309 } 310 311 /* Enforce the block group descriptor size */ 312 if (ext2fs_has_feature_64bit(fs->super)) { 313 if (fs->super->s_desc_size < EXT2_MIN_DESC_SIZE_64BIT) { 314 retval = EXT2_ET_BAD_DESC_SIZE; 315 goto cleanup; 316 } 317 } else { 318 if (fs->super->s_desc_size && 319 fs->super->s_desc_size != EXT2_MIN_DESC_SIZE) { 320 retval = EXT2_ET_BAD_DESC_SIZE; 321 goto cleanup; 322 } 323 } 324 325 fs->cluster_ratio_bits = fs->super->s_log_cluster_size - 326 fs->super->s_log_block_size; 327 if (EXT2_BLOCKS_PER_GROUP(fs->super) != 328 EXT2_CLUSTERS_PER_GROUP(fs->super) << fs->cluster_ratio_bits) { 329 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 330 goto cleanup; 331 } 332 fs->inode_blocks_per_group = ((EXT2_INODES_PER_GROUP(fs->super) * 333 EXT2_INODE_SIZE(fs->super) + 334 EXT2_BLOCK_SIZE(fs->super) - 1) / 335 EXT2_BLOCK_SIZE(fs->super)); 336 if (block_size) { 337 if (block_size != fs->blocksize) { 338 retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE; 339 goto cleanup; 340 } 341 } 342 /* 343 * Set the blocksize to the filesystem's blocksize. 344 */ 345 io_channel_set_blksize(fs->io, fs->blocksize); 346 347 /* 348 * If this is an external journal device, don't try to read 349 * the group descriptors, because they're not there. 350 */ 351 if (ext2fs_has_feature_journal_dev(fs->super)) { 352 fs->group_desc_count = 0; 353 *ret_fs = fs; 354 return 0; 355 } 356 357 if (EXT2_INODES_PER_GROUP(fs->super) == 0) { 358 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 359 goto cleanup; 360 } 361 /* Precompute the FS UUID to seed other checksums */ 362 ext2fs_init_csum_seed(fs); 363 364 /* 365 * Read group descriptors 366 */ 367 blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super); 368 if (blocks_per_group == 0 || 369 blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) || 370 fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super) || 371 EXT2_DESC_PER_BLOCK(fs->super) == 0 || 372 fs->super->s_first_data_block >= ext2fs_blocks_count(fs->super)) { 373 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 374 goto cleanup; 375 } 376 fs->group_desc_count = ext2fs_div64_ceil(ext2fs_blocks_count(fs->super) - 377 fs->super->s_first_data_block, 378 blocks_per_group); 379 if (fs->group_desc_count * EXT2_INODES_PER_GROUP(fs->super) != 380 fs->super->s_inodes_count) { 381 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 382 goto cleanup; 383 } 384 fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count, 385 EXT2_DESC_PER_BLOCK(fs->super)); 386 retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize, 387 &fs->group_desc); 388 if (retval) 389 goto cleanup; 390 if (!group_block) 391 group_block = fs->super->s_first_data_block; 392 /* 393 * On a FS with a 1K blocksize, block 0 is reserved for bootloaders 394 * so we must increment block numbers to any group 0 items. 395 * 396 * However, we cannot touch group_block directly because in the meta_bg 397 * case, the ext2fs_descriptor_block_loc2() function will interpret 398 * group_block != s_first_data_block to mean that we want to access the 399 * backup group descriptors. This is not what we want if the caller 400 * set superblock == 0 (i.e. auto-detect the superblock), which is 401 * what's going on here. 402 */ 403 if (group_block == 0 && fs->blocksize == 1024) 404 group_zero_adjust = 1; 405 dest = (char *) fs->group_desc; 406#ifdef WORDS_BIGENDIAN 407 groups_per_block = EXT2_DESC_PER_BLOCK(fs->super); 408#endif 409 if (ext2fs_has_feature_meta_bg(fs->super)) { 410 first_meta_bg = fs->super->s_first_meta_bg; 411 if (first_meta_bg > fs->desc_blocks) 412 first_meta_bg = fs->desc_blocks; 413 } else 414 first_meta_bg = fs->desc_blocks; 415 if (first_meta_bg) { 416 retval = io_channel_read_blk(fs->io, group_block + 417 group_zero_adjust + 1, 418 first_meta_bg, dest); 419 if (retval) 420 goto cleanup; 421#ifdef WORDS_BIGENDIAN 422 gdp = (struct ext2_group_desc *) dest; 423 for (j=0; j < groups_per_block*first_meta_bg; j++) { 424 gdp = ext2fs_group_desc(fs, fs->group_desc, j); 425 ext2fs_swap_group_desc2(fs, gdp); 426 } 427#endif 428 dest += fs->blocksize*first_meta_bg; 429 } 430 for (i=first_meta_bg ; i < fs->desc_blocks; i++) { 431 blk = ext2fs_descriptor_block_loc2(fs, group_block, i); 432 retval = io_channel_read_blk64(fs->io, blk, 1, dest); 433 if (retval) 434 goto cleanup; 435#ifdef WORDS_BIGENDIAN 436 for (j=0; j < groups_per_block; j++) { 437 gdp = ext2fs_group_desc(fs, fs->group_desc, 438 i * groups_per_block + j); 439 ext2fs_swap_group_desc2(fs, gdp); 440 } 441#endif 442 dest += fs->blocksize; 443 } 444 445 fs->stride = fs->super->s_raid_stride; 446 447 /* 448 * If recovery is from backup superblock, Clear _UNININT flags & 449 * reset bg_itable_unused to zero 450 */ 451 if (superblock > 1 && ext2fs_has_group_desc_csum(fs)) { 452 dgrp_t group; 453 454 for (group = 0; group < fs->group_desc_count; group++) { 455 ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT); 456 ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT); 457 ext2fs_bg_itable_unused_set(fs, group, 0); 458 /* The checksum will be reset later, but fix it here 459 * anyway to avoid printing a lot of spurious errors. */ 460 ext2fs_group_desc_csum_set(fs, group); 461 } 462 if (fs->flags & EXT2_FLAG_RW) 463 ext2fs_mark_super_dirty(fs); 464 } 465 466 if (ext2fs_has_feature_mmp(fs->super) && 467 !(flags & EXT2_FLAG_SKIP_MMP) && 468 (flags & (EXT2_FLAG_RW | EXT2_FLAG_EXCLUSIVE))) { 469 retval = ext2fs_mmp_start(fs); 470 if (retval) { 471 fs->flags |= EXT2_FLAG_SKIP_MMP; /* just do cleanup */ 472 ext2fs_mmp_stop(fs); 473 goto cleanup; 474 } 475 } 476 477 fs->flags &= ~EXT2_FLAG_NOFREE_ON_ERROR; 478 *ret_fs = fs; 479 480 return 0; 481cleanup: 482 if (!(flags & EXT2_FLAG_NOFREE_ON_ERROR)) { 483 ext2fs_free(fs); 484 fs = NULL; 485 } 486 *ret_fs = fs; 487 return retval; 488} 489 490/* 491 * Set/get the filesystem data I/O channel. 492 * 493 * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true. 494 */ 495errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io) 496{ 497 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) 498 return EXT2_ET_NOT_IMAGE_FILE; 499 if (old_io) { 500 *old_io = (fs->image_io == fs->io) ? 0 : fs->io; 501 } 502 return 0; 503} 504 505errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io) 506{ 507 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) 508 return EXT2_ET_NOT_IMAGE_FILE; 509 fs->io = new_io ? new_io : fs->image_io; 510 return 0; 511} 512 513errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io) 514{ 515 errcode_t err; 516 517 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) 518 return EXT2_ET_NOT_IMAGE_FILE; 519 err = io_channel_set_blksize(new_io, fs->blocksize); 520 if (err) 521 return err; 522 if ((new_io == fs->image_io) || (new_io == fs->io)) 523 return 0; 524 if ((fs->image_io != fs->io) && 525 fs->image_io) 526 io_channel_close(fs->image_io); 527 if (fs->io) 528 io_channel_close(fs->io); 529 fs->io = fs->image_io = new_io; 530 fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW | 531 EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY; 532 fs->flags &= ~EXT2_FLAG_IMAGE_FILE; 533 return 0; 534} 535