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 <stdio.h> 13 #include <string.h> 14 #if HAVE_UNISTD_H 15 #include <unistd.h> 16 #endif 17 #include <fcntl.h> 18 #include <time.h> 19 #if HAVE_SYS_STAT_H 20 #include <sys/stat.h> 21 #endif 22 #if HAVE_SYS_TYPES_H 23 #include <sys/types.h> 24 #endif 25 #ifdef HAVE_ERRNO_H 26 #include <errno.h> 27 #endif 28 29 #include "ext2_fs.h" 30 31 32 #include "ext2fs.h" 33 #include "e2image.h" 34 35 blk64_t ext2fs_descriptor_block_loc2(ext2_filsys fs, blk64_t group_block, 36 dgrp_t i) 37 { 38 int bg; 39 int has_super = 0; 40 blk64_t ret_blk; 41 42 if (!(fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) || 43 (i < fs->super->s_first_meta_bg)) 44 return (group_block + i + 1); 45 46 bg = EXT2_DESC_PER_BLOCK(fs->super) * i; 47 if (ext2fs_bg_has_super(fs, bg)) 48 has_super = 1; 49 ret_blk = ext2fs_group_first_block2(fs, bg) + has_super; 50 /* 51 * If group_block is not the normal value, we're trying to use 52 * the backup group descriptors and superblock --- so use the 53 * alternate location of the second block group in the 54 * metablock group. Ideally we should be testing each bg 55 * descriptor block individually for correctness, but we don't 56 * have the infrastructure in place to do that. 57 */ 58 if (group_block != fs->super->s_first_data_block && 59 ((ret_blk + fs->super->s_blocks_per_group) < 60 ext2fs_blocks_count(fs->super))) 61 ret_blk += fs->super->s_blocks_per_group; 62 return ret_blk; 63 } 64 65 blk_t ext2fs_descriptor_block_loc(ext2_filsys fs, blk_t group_block, dgrp_t i) 66 { 67 return ext2fs_descriptor_block_loc2(fs, group_block, i); 68 } 69 70 errcode_t ext2fs_open(const char *name, int flags, int superblock, 71 unsigned int block_size, io_manager manager, 72 ext2_filsys *ret_fs) 73 { 74 return ext2fs_open2(name, 0, flags, superblock, block_size, 75 manager, ret_fs); 76 } 77 78 /* 79 * Note: if superblock is non-zero, block-size must also be non-zero. 80 * Superblock and block_size can be zero to use the default size. 81 * 82 * Valid flags for ext2fs_open() 83 * 84 * EXT2_FLAG_RW - Open the filesystem for read/write. 85 * EXT2_FLAG_FORCE - Open the filesystem even if some of the 86 * features aren't supported. 87 * EXT2_FLAG_JOURNAL_DEV_OK - Open an ext3 journal device 88 * EXT2_FLAG_SKIP_MMP - Open without multi-mount protection check. 89 * EXT2_FLAG_64BITS - Allow 64-bit bitfields (needed for large 90 * filesystems) 91 */ 92 errcode_t ext2fs_open2(const char *name, const char *io_options, 93 int flags, int superblock, 94 unsigned int block_size, io_manager manager, 95 ext2_filsys *ret_fs) 96 { 97 ext2_filsys fs; 98 errcode_t retval; 99 unsigned long i, first_meta_bg; 100 __u32 features; 101 unsigned int blocks_per_group, io_flags; 102 blk64_t group_block, blk; 103 char *dest, *cp; 104 #ifdef WORDS_BIGENDIAN 105 unsigned int groups_per_block; 106 struct ext2_group_desc *gdp; 107 int j; 108 #endif 109 110 EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER); 111 112 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs); 113 if (retval) 114 return retval; 115 116 memset(fs, 0, sizeof(struct struct_ext2_filsys)); 117 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS; 118 fs->flags = flags; 119 /* don't overwrite sb backups unless flag is explicitly cleared */ 120 fs->flags |= EXT2_FLAG_MASTER_SB_ONLY; 121 fs->umask = 022; 122 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name); 123 if (retval) 124 goto cleanup; 125 strcpy(fs->device_name, name); 126 cp = strchr(fs->device_name, '?'); 127 if (!io_options && cp) { 128 *cp++ = 0; 129 io_options = cp; 130 } 131 132 io_flags = 0; 133 if (flags & EXT2_FLAG_RW) 134 io_flags |= IO_FLAG_RW; 135 if (flags & EXT2_FLAG_EXCLUSIVE) 136 io_flags |= IO_FLAG_EXCLUSIVE; 137 if (flags & EXT2_FLAG_DIRECT_IO) 138 io_flags |= IO_FLAG_DIRECT_IO; 139 retval = manager->open(fs->device_name, io_flags, &fs->io); 140 if (retval) 141 goto cleanup; 142 if (io_options && 143 (retval = io_channel_set_options(fs->io, io_options))) 144 goto cleanup; 145 fs->image_io = fs->io; 146 fs->io->app_data = fs; 147 retval = io_channel_alloc_buf(fs->io, -SUPERBLOCK_SIZE, &fs->super); 148 if (retval) 149 goto cleanup; 150 if (flags & EXT2_FLAG_IMAGE_FILE) { 151 retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr), 152 &fs->image_header); 153 if (retval) 154 goto cleanup; 155 retval = io_channel_read_blk(fs->io, 0, 156 -(int)sizeof(struct ext2_image_hdr), 157 fs->image_header); 158 if (retval) 159 goto cleanup; 160 if (fs->image_header->magic_number != EXT2_ET_MAGIC_E2IMAGE) 161 return EXT2_ET_MAGIC_E2IMAGE; 162 superblock = 1; 163 block_size = fs->image_header->fs_blocksize; 164 } 165 166 /* 167 * If the user specifies a specific block # for the 168 * superblock, then he/she must also specify the block size! 169 * Otherwise, read the master superblock located at offset 170 * SUPERBLOCK_OFFSET from the start of the partition. 171 * 172 * Note: we only save a backup copy of the superblock if we 173 * are reading the superblock from the primary superblock location. 174 */ 175 if (superblock) { 176 if (!block_size) { 177 retval = EXT2_ET_INVALID_ARGUMENT; 178 goto cleanup; 179 } 180 io_channel_set_blksize(fs->io, block_size); 181 group_block = superblock; 182 fs->orig_super = 0; 183 } else { 184 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET); 185 superblock = 1; 186 group_block = 0; 187 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super); 188 if (retval) 189 goto cleanup; 190 } 191 retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE, 192 fs->super); 193 if (retval) 194 goto cleanup; 195 if (fs->orig_super) 196 memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE); 197 198 #ifdef WORDS_BIGENDIAN 199 fs->flags |= EXT2_FLAG_SWAP_BYTES; 200 ext2fs_swap_super(fs->super); 201 #else 202 if (fs->flags & EXT2_FLAG_SWAP_BYTES) { 203 retval = EXT2_ET_UNIMPLEMENTED; 204 goto cleanup; 205 } 206 #endif 207 208 if (fs->super->s_magic != EXT2_SUPER_MAGIC) { 209 retval = EXT2_ET_BAD_MAGIC; 210 goto cleanup; 211 } 212 if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) { 213 retval = EXT2_ET_REV_TOO_HIGH; 214 goto cleanup; 215 } 216 217 /* 218 * Check for feature set incompatibility 219 */ 220 if (!(flags & EXT2_FLAG_FORCE)) { 221 features = fs->super->s_feature_incompat; 222 #ifdef EXT2_LIB_SOFTSUPP_INCOMPAT 223 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES) 224 features &= ~EXT2_LIB_SOFTSUPP_INCOMPAT; 225 #endif 226 if (features & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) { 227 retval = EXT2_ET_UNSUPP_FEATURE; 228 goto cleanup; 229 } 230 231 features = fs->super->s_feature_ro_compat; 232 #ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT 233 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES) 234 features &= ~EXT2_LIB_SOFTSUPP_RO_COMPAT; 235 #endif 236 if ((flags & EXT2_FLAG_RW) && 237 (features & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) { 238 retval = EXT2_ET_RO_UNSUPP_FEATURE; 239 goto cleanup; 240 } 241 242 if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) && 243 (fs->super->s_feature_incompat & 244 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)) { 245 retval = EXT2_ET_UNSUPP_FEATURE; 246 goto cleanup; 247 } 248 } 249 250 if ((fs->super->s_log_block_size + EXT2_MIN_BLOCK_LOG_SIZE) > 251 EXT2_MAX_BLOCK_LOG_SIZE) { 252 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 253 goto cleanup; 254 } 255 256 /* 257 * bigalloc requires cluster-aware bitfield operations, which at the 258 * moment means we need EXT2_FLAG_64BITS. 259 */ 260 if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super, 261 EXT4_FEATURE_RO_COMPAT_BIGALLOC) && 262 !(flags & EXT2_FLAG_64BITS)) { 263 retval = EXT2_ET_CANT_USE_LEGACY_BITMAPS; 264 goto cleanup; 265 } 266 267 if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super, 268 EXT4_FEATURE_RO_COMPAT_BIGALLOC) && 269 (fs->super->s_log_block_size != fs->super->s_log_cluster_size)) { 270 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 271 goto cleanup; 272 } 273 fs->fragsize = fs->blocksize = EXT2_BLOCK_SIZE(fs->super); 274 if (EXT2_INODE_SIZE(fs->super) < EXT2_GOOD_OLD_INODE_SIZE) { 275 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 276 goto cleanup; 277 } 278 fs->cluster_ratio_bits = fs->super->s_log_cluster_size - 279 fs->super->s_log_block_size; 280 if (EXT2_BLOCKS_PER_GROUP(fs->super) != 281 EXT2_CLUSTERS_PER_GROUP(fs->super) << fs->cluster_ratio_bits) { 282 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 283 goto cleanup; 284 } 285 fs->inode_blocks_per_group = ((EXT2_INODES_PER_GROUP(fs->super) * 286 EXT2_INODE_SIZE(fs->super) + 287 EXT2_BLOCK_SIZE(fs->super) - 1) / 288 EXT2_BLOCK_SIZE(fs->super)); 289 if (block_size) { 290 if (block_size != fs->blocksize) { 291 retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE; 292 goto cleanup; 293 } 294 } 295 /* 296 * Set the blocksize to the filesystem's blocksize. 297 */ 298 io_channel_set_blksize(fs->io, fs->blocksize); 299 300 /* 301 * If this is an external journal device, don't try to read 302 * the group descriptors, because they're not there. 303 */ 304 if (fs->super->s_feature_incompat & 305 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) { 306 fs->group_desc_count = 0; 307 *ret_fs = fs; 308 return 0; 309 } 310 311 if (EXT2_INODES_PER_GROUP(fs->super) == 0) { 312 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 313 goto cleanup; 314 } 315 316 /* 317 * Read group descriptors 318 */ 319 blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super); 320 if (blocks_per_group == 0 || 321 blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) || 322 fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super) || 323 EXT2_DESC_PER_BLOCK(fs->super) == 0 || 324 fs->super->s_first_data_block >= ext2fs_blocks_count(fs->super)) { 325 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 326 goto cleanup; 327 } 328 fs->group_desc_count = ext2fs_div64_ceil(ext2fs_blocks_count(fs->super) - 329 fs->super->s_first_data_block, 330 blocks_per_group); 331 if (fs->group_desc_count * EXT2_INODES_PER_GROUP(fs->super) != 332 fs->super->s_inodes_count) { 333 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 334 goto cleanup; 335 } 336 fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count, 337 EXT2_DESC_PER_BLOCK(fs->super)); 338 retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize, 339 &fs->group_desc); 340 if (retval) 341 goto cleanup; 342 if (!group_block) 343 group_block = fs->super->s_first_data_block; 344 if (group_block == 0 && fs->blocksize == 1024) 345 group_block = 1; /* Deal with 1024 blocksize && bigalloc */ 346 dest = (char *) fs->group_desc; 347 #ifdef WORDS_BIGENDIAN 348 groups_per_block = EXT2_DESC_PER_BLOCK(fs->super); 349 #endif 350 if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) 351 first_meta_bg = fs->super->s_first_meta_bg; 352 else 353 first_meta_bg = fs->desc_blocks; 354 if (first_meta_bg) { 355 retval = io_channel_read_blk(fs->io, group_block+1, 356 first_meta_bg, dest); 357 if (retval) 358 goto cleanup; 359 #ifdef WORDS_BIGENDIAN 360 gdp = (struct ext2_group_desc *) dest; 361 for (j=0; j < groups_per_block*first_meta_bg; j++) { 362 gdp = ext2fs_group_desc(fs, fs->group_desc, j); 363 ext2fs_swap_group_desc2(fs, gdp); 364 } 365 #endif 366 dest += fs->blocksize*first_meta_bg; 367 } 368 for (i=first_meta_bg ; i < fs->desc_blocks; i++) { 369 blk = ext2fs_descriptor_block_loc2(fs, group_block, i); 370 retval = io_channel_read_blk64(fs->io, blk, 1, dest); 371 if (retval) 372 goto cleanup; 373 #ifdef WORDS_BIGENDIAN 374 for (j=0; j < groups_per_block; j++) { 375 gdp = ext2fs_group_desc(fs, fs->group_desc, 376 i * groups_per_block + j); 377 ext2fs_swap_group_desc2(fs, gdp); 378 } 379 #endif 380 dest += fs->blocksize; 381 } 382 383 fs->stride = fs->super->s_raid_stride; 384 385 /* 386 * If recovery is from backup superblock, Clear _UNININT flags & 387 * reset bg_itable_unused to zero 388 */ 389 if (superblock > 1 && EXT2_HAS_RO_COMPAT_FEATURE(fs->super, 390 EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) { 391 dgrp_t group; 392 393 for (group = 0; group < fs->group_desc_count; group++) { 394 ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT); 395 ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT); 396 ext2fs_bg_itable_unused_set(fs, group, 0); 397 /* The checksum will be reset later, but fix it here 398 * anyway to avoid printing a lot of spurious errors. */ 399 ext2fs_group_desc_csum_set(fs, group); 400 } 401 if (fs->flags & EXT2_FLAG_RW) 402 ext2fs_mark_super_dirty(fs); 403 } 404 405 if ((fs->super->s_feature_incompat & EXT4_FEATURE_INCOMPAT_MMP) && 406 !(flags & EXT2_FLAG_SKIP_MMP) && 407 (flags & (EXT2_FLAG_RW | EXT2_FLAG_EXCLUSIVE))) { 408 retval = ext2fs_mmp_start(fs); 409 if (retval) { 410 fs->flags |= EXT2_FLAG_SKIP_MMP; /* just do cleanup */ 411 ext2fs_mmp_stop(fs); 412 goto cleanup; 413 } 414 } 415 416 fs->flags &= ~EXT2_FLAG_NOFREE_ON_ERROR; 417 *ret_fs = fs; 418 419 return 0; 420 cleanup: 421 if (flags & EXT2_FLAG_NOFREE_ON_ERROR) 422 *ret_fs = fs; 423 else 424 ext2fs_free(fs); 425 return retval; 426 } 427 428 /* 429 * Set/get the filesystem data I/O channel. 430 * 431 * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true. 432 */ 433 errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io) 434 { 435 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) 436 return EXT2_ET_NOT_IMAGE_FILE; 437 if (old_io) { 438 *old_io = (fs->image_io == fs->io) ? 0 : fs->io; 439 } 440 return 0; 441 } 442 443 errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io) 444 { 445 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) 446 return EXT2_ET_NOT_IMAGE_FILE; 447 fs->io = new_io ? new_io : fs->image_io; 448 return 0; 449 } 450 451 errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io) 452 { 453 errcode_t err; 454 455 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) 456 return EXT2_ET_NOT_IMAGE_FILE; 457 err = io_channel_set_blksize(new_io, fs->blocksize); 458 if (err) 459 return err; 460 if ((new_io == fs->image_io) || (new_io == fs->io)) 461 return 0; 462 if ((fs->image_io != fs->io) && 463 fs->image_io) 464 io_channel_close(fs->image_io); 465 if (fs->io) 466 io_channel_close(fs->io); 467 fs->io = fs->image_io = new_io; 468 fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW | 469 EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY; 470 fs->flags &= ~EXT2_FLAG_IMAGE_FILE; 471 return 0; 472 } 473
