lib/ext2fs/openfs.c

   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 #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, group_zero_adjust = 0;
  40         blk64_t ret_blk;
  41
  42         /*
  43          * On a bigalloc FS with 1K blocks, block 0 is reserved for non-ext4
  44          * stuff, so adjust for that if we're being asked for group 0.
  45          */
  46         if (i == 0 && fs->blocksize == 1024 && EXT2FS_CLUSTER_RATIO(fs) > 1)
  47                 group_zero_adjust = 1;
  48
  49         if (!ext2fs_has_feature_meta_bg(fs->super) ||
  50             (i < fs->super->s_first_meta_bg))
  51                 return group_block + i + 1 + group_zero_adjust;
  52
  53         bg = EXT2_DESC_PER_BLOCK(fs->super) * i;
  54         if (ext2fs_bg_has_super(fs, bg))
  55                 has_super = 1;
  56         ret_blk = ext2fs_group_first_block2(fs, bg);
  57         /*
  58          * If group_block is not the normal value, we're trying to use
  59          * the backup group descriptors and superblock --- so use the
  60          * alternate location of the second block group in the
  61          * metablock group.  Ideally we should be testing each bg
  62          * descriptor block individually for correctness, but we don't
  63          * have the infrastructure in place to do that.
  64          */
  65         if (group_block != fs->super->s_first_data_block &&
  66             ((ret_blk + has_super + fs->super->s_blocks_per_group) <
  67              ext2fs_blocks_count(fs->super))) {
  68                 ret_blk += fs->super->s_blocks_per_group;
  69
  70                 /*
  71                  * If we're going to jump forward a block group, make sure
  72                  * that we adjust has_super to account for the next group's
  73                  * backup superblock (or lack thereof).
  74                  */
  75                 if (ext2fs_bg_has_super(fs, bg + 1))
  76                         has_super = 1;
  77                 else
  78                         has_super = 0;
  79         }
  80         return ret_blk + has_super + group_zero_adjust;
  81 }
  82
  83 blk_t ext2fs_descriptor_block_loc(ext2_filsys fs, blk_t group_block, dgrp_t i)
  84 {
  85         return ext2fs_descriptor_block_loc2(fs, group_block, i);
  86 }
  87
  88 errcode_t ext2fs_open(const char *name, int flags, int superblock,
  89                       unsigned int block_size, io_manager manager,
  90                       ext2_filsys *ret_fs)
  91 {
  92         return ext2fs_open2(name, 0, flags, superblock, block_size,
  93                             manager, ret_fs);
  94 }
  95
  96 static void block_sha_map_free_entry(void *data)
  97 {
  98         free(data);
  99         return;
 100 }
 101
 102 /*
 103  *  Note: if superblock is non-zero, block-size must also be non-zero.
 104  *      Superblock and block_size can be zero to use the default size.
 105  *
 106  * Valid flags for ext2fs_open()
 107  *
 108  *      EXT2_FLAG_RW    - Open the filesystem for read/write.
 109  *      EXT2_FLAG_FORCE - Open the filesystem even if some of the
 110  *                              features aren't supported.
 111  *      EXT2_FLAG_JOURNAL_DEV_OK - Open an ext3 journal device
 112  *      EXT2_FLAG_SKIP_MMP - Open without multi-mount protection check.
 113  *      EXT2_FLAG_64BITS - Allow 64-bit bitfields (needed for large
 114  *                              filesystems)
 115  */
 116 errcode_t ext2fs_open2(const char *name, const char *io_options,
 117                        int flags, int superblock,
 118                        unsigned int block_size, io_manager manager,
 119                        ext2_filsys *ret_fs)
 120 {
 121         ext2_filsys     fs;
 122         errcode_t       retval;
 123         unsigned long   i, first_meta_bg;
 124         __u32           features;
 125         unsigned int    blocks_per_group, io_flags;
 126         blk64_t         group_block, blk;
 127         char            *dest, *cp;
 128         int             group_zero_adjust = 0;
 129         unsigned int    inode_size;
 130         __u64           groups_cnt;
 131 #ifdef WORDS_BIGENDIAN
 132         unsigned int    groups_per_block;
 133         struct ext2_group_desc *gdp;
 134         int             j;
 135 #endif
 136         char            *time_env;
 137         int             csum_retries = 0;
 138
 139         EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER);
 140
 141         retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
 142         if (retval)
 143                 return retval;
 144
 145         memset(fs, 0, sizeof(struct struct_ext2_filsys));
 146         fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
 147         fs->flags = flags;
 148         /* don't overwrite sb backups unless flag is explicitly cleared */
 149         fs->flags |= EXT2_FLAG_MASTER_SB_ONLY;
 150         fs->umask = 022;
 151
 152         time_env = ext2fs_safe_getenv("SOURCE_DATE_EPOCH");
 153         if (time_env) {
 154                 fs->now = strtoul(time_env, NULL, 0);
 155                 fs->flags2 |= EXT2_FLAG2_USE_FAKE_TIME;
 156         } else {
 157                 time_env = ext2fs_safe_getenv("E2FSPROGS_FAKE_TIME");
 158                 if (time_env)
 159                         fs->now = strtoul(time_env, NULL, 0);
 160         }
 161
 162         retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
 163         if (retval)
 164                 goto cleanup;
 165         strcpy(fs->device_name, name);
 166         cp = strchr(fs->device_name, '?');
 167         if (!io_options && cp) {
 168                 *cp++ = 0;
 169                 io_options = cp;
 170         }
 171
 172         io_flags = 0;
 173         if (flags & EXT2_FLAG_RW)
 174                 io_flags |= IO_FLAG_RW;
 175         if (flags & EXT2_FLAG_EXCLUSIVE)
 176                 io_flags |= IO_FLAG_EXCLUSIVE;
 177         if (flags & EXT2_FLAG_DIRECT_IO)
 178                 io_flags |= IO_FLAG_DIRECT_IO;
 179         if (flags & EXT2_FLAG_THREADS)
 180                 io_flags |= IO_FLAG_THREADS;
 181         retval = manager->open(fs->device_name, io_flags, &fs->io);
 182         if (retval)
 183                 goto cleanup;
 184         if (io_options &&
 185             (retval = io_channel_set_options(fs->io, io_options)))
 186                 goto cleanup;
 187         fs->image_io = fs->io;
 188         fs->io->app_data = fs;
 189         retval = io_channel_alloc_buf(fs->io, -SUPERBLOCK_SIZE, &fs->super);
 190         if (retval)
 191                 goto cleanup;
 192         if (flags & EXT2_FLAG_IMAGE_FILE) {
 193                 retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr),
 194                                         &fs->image_header);
 195                 if (retval)
 196                         goto cleanup;
 197                 retval = io_channel_read_blk(fs->io, 0,
 198                                              -(int)sizeof(struct ext2_image_hdr),
 199                                              fs->image_header);
 200                 if (retval)
 201                         goto cleanup;
 202                 if (ext2fs_le32_to_cpu(fs->image_header->magic_number) != EXT2_ET_MAGIC_E2IMAGE)
 203                         return EXT2_ET_MAGIC_E2IMAGE;
 204                 superblock = 1;
 205                 block_size = ext2fs_le32_to_cpu(fs->image_header->fs_blocksize);
 206         }
 207
 208         /*
 209          * If the user specifies a specific block # for the
 210          * superblock, then he/she must also specify the block size!
 211          * Otherwise, read the master superblock located at offset
 212          * SUPERBLOCK_OFFSET from the start of the partition.
 213          *
 214          * Note: we only save a backup copy of the superblock if we
 215          * are reading the superblock from the primary superblock location.
 216          */
 217         if (superblock) {
 218                 if (!block_size) {
 219                         retval = EXT2_ET_INVALID_ARGUMENT;
 220                         goto cleanup;
 221                 }
 222                 io_channel_set_blksize(fs->io, block_size);
 223                 group_block = superblock;
 224                 fs->orig_super = 0;
 225         } else {
 226                 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
 227                 superblock = 1;
 228                 group_block = 0;
 229                 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super);
 230                 if (retval)
 231                         goto cleanup;
 232         }
 233 retry:
 234         retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE,
 235                                      fs->super);
 236         if (retval)
 237                 goto cleanup;
 238         if (fs->orig_super)
 239                 memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE);
 240
 241         if (!(fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS)) {
 242                 retval = 0;
 243                 if (!ext2fs_verify_csum_type(fs, fs->super))
 244                         retval = EXT2_ET_UNKNOWN_CSUM;
 245                 if (!ext2fs_superblock_csum_verify(fs, fs->super)) {
 246                         if (csum_retries++ < 3)
 247                                 goto retry;
 248                         retval = EXT2_ET_SB_CSUM_INVALID;
 249                 }
 250         }
 251
 252 #ifdef WORDS_BIGENDIAN
 253         fs->flags |= EXT2_FLAG_SWAP_BYTES;
 254         ext2fs_swap_super(fs->super);
 255 #else
 256         if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
 257                 retval = EXT2_ET_UNIMPLEMENTED;
 258                 goto cleanup;
 259         }
 260 #endif
 261
 262         if (fs->super->s_magic != EXT2_SUPER_MAGIC)
 263                 retval = EXT2_ET_BAD_MAGIC;
 264         if (retval)
 265                 goto cleanup;
 266
 267         if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) {
 268                 retval = EXT2_ET_REV_TOO_HIGH;
 269                 goto cleanup;
 270         }
 271
 272         /*
 273          * Check for feature set incompatibility
 274          */
 275         if (!(flags & EXT2_FLAG_FORCE)) {
 276                 features = fs->super->s_feature_incompat;
 277 #ifdef EXT2_LIB_SOFTSUPP_INCOMPAT
 278                 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
 279                         features &= ~EXT2_LIB_SOFTSUPP_INCOMPAT;
 280 #endif
 281                 if (features & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
 282                         retval = EXT2_ET_UNSUPP_FEATURE;
 283                         goto cleanup;
 284                 }
 285
 286                 features = fs->super->s_feature_ro_compat;
 287 #ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT
 288                 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
 289                         features &= ~EXT2_LIB_SOFTSUPP_RO_COMPAT;
 290 #endif
 291                 if ((flags & EXT2_FLAG_RW) &&
 292                     (features & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) {
 293                         retval = EXT2_ET_RO_UNSUPP_FEATURE;
 294                         goto cleanup;
 295                 }
 296
 297                 if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) &&
 298                     ext2fs_has_feature_journal_dev(fs->super)) {
 299                         retval = EXT2_ET_UNSUPP_FEATURE;
 300                         goto cleanup;
 301                 }
 302         }
 303
 304         if ((fs->super->s_log_block_size >
 305              (unsigned) (EXT2_MAX_BLOCK_LOG_SIZE - EXT2_MIN_BLOCK_LOG_SIZE)) ||
 306             (fs->super->s_log_cluster_size >
 307              (unsigned) (EXT2_MAX_CLUSTER_LOG_SIZE - EXT2_MIN_CLUSTER_LOG_SIZE)) ||
 308             (fs->super->s_log_block_size > fs->super->s_log_cluster_size) ||
 309             (fs->super->s_log_groups_per_flex > 31)) {
 310                 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
 311                 goto cleanup;
 312         }
 313
 314         /*
 315          * bigalloc requires cluster-aware bitfield operations, which at the
 316          * moment means we need EXT2_FLAG_64BITS.
 317          */
 318         if (ext2fs_has_feature_bigalloc(fs->super) &&
 319             !(flags & EXT2_FLAG_64BITS)) {
 320                 retval = EXT2_ET_CANT_USE_LEGACY_BITMAPS;
 321                 goto cleanup;
 322         }
 323
 324         if (!ext2fs_has_feature_bigalloc(fs->super) &&
 325             (fs->super->s_log_block_size != fs->super->s_log_cluster_size)) {
 326                 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
 327                 goto cleanup;
 328         }
 329         fs->fragsize = fs->blocksize = EXT2_BLOCK_SIZE(fs->super);
 330         inode_size = EXT2_INODE_SIZE(fs->super);
 331         if ((inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 332             (inode_size > fs->blocksize) ||
 333             (inode_size & (inode_size - 1))) {
 334                 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
 335                 goto cleanup;
 336         }
 337
 338         /* Enforce the block group descriptor size */
 339         if (ext2fs_has_feature_64bit(fs->super)) {
 340                 unsigned desc_size = fs->super->s_desc_size;
 341
 342                 if (desc_size == 0 ||
 343                     (!(flags & EXT2_FLAG_IGNORE_SB_ERRORS) &&
 344                      ((desc_size > EXT2_MAX_DESC_SIZE) ||
 345                       (desc_size < EXT2_MIN_DESC_SIZE_64BIT) ||
 346                       (desc_size & (desc_size - 1)) != 0))) {
 347                         retval = EXT2_ET_BAD_DESC_SIZE;
 348                         goto cleanup;
 349                 }
 350         }
 351
 352         fs->cluster_ratio_bits = fs->super->s_log_cluster_size -
 353                 fs->super->s_log_block_size;
 354         if (EXT2_BLOCKS_PER_GROUP(fs->super) !=
 355             EXT2_CLUSTERS_PER_GROUP(fs->super) << fs->cluster_ratio_bits) {
 356                 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
 357                 goto cleanup;
 358         }
 359         fs->inode_blocks_per_group = ((EXT2_INODES_PER_GROUP(fs->super) *
 360                                        EXT2_INODE_SIZE(fs->super) +
 361                                        EXT2_BLOCK_SIZE(fs->super) - 1) /
 362                                       EXT2_BLOCK_SIZE(fs->super));
 363         if (block_size) {
 364                 if (block_size != fs->blocksize) {
 365                         retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE;
 366                         goto cleanup;
 367                 }
 368         }
 369         /*
 370          * Set the blocksize to the filesystem's blocksize.
 371          */
 372         io_channel_set_blksize(fs->io, fs->blocksize);
 373
 374         /*
 375          * If this is an external journal device, don't try to read
 376          * the group descriptors, because they're not there.
 377          */
 378         if (ext2fs_has_feature_journal_dev(fs->super)) {
 379                 fs->group_desc_count = 0;
 380                 *ret_fs = fs;
 381                 return 0;
 382         }
 383
 384         if (EXT2_INODES_PER_GROUP(fs->super) == 0) {
 385                 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
 386                 goto cleanup;
 387         }
 388         /* Precompute the FS UUID to seed other checksums */
 389         ext2fs_init_csum_seed(fs);
 390
 391         /*
 392          * Read group descriptors
 393          */
 394         blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super);
 395         if (blocks_per_group < 8 ||
 396             blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) ||
 397             fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super) ||
 398            EXT2_DESC_PER_BLOCK(fs->super) == 0 ||
 399            fs->super->s_first_data_block >= ext2fs_blocks_count(fs->super)) {
 400                 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
 401                 goto cleanup;
 402         }
 403         groups_cnt = ext2fs_div64_ceil(ext2fs_blocks_count(fs->super) -
 404                                        fs->super->s_first_data_block,
 405                                        blocks_per_group);
 406         if (groups_cnt >> 32) {
 407                 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
 408                 goto cleanup;
 409         }
 410         fs->group_desc_count =  groups_cnt;
 411         if (!(flags & EXT2_FLAG_IGNORE_SB_ERRORS) &&
 412             (__u64)fs->group_desc_count * EXT2_INODES_PER_GROUP(fs->super) !=
 413             fs->super->s_inodes_count) {
 414                 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
 415                 goto cleanup;
 416         }
 417         fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
 418                                           EXT2_DESC_PER_BLOCK(fs->super));
 419         if (ext2fs_has_feature_meta_bg(fs->super) &&
 420             (fs->super->s_first_meta_bg > fs->desc_blocks) &&
 421             !(flags & EXT2_FLAG_IGNORE_SB_ERRORS)) {
 422                 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
 423                 goto cleanup;
 424         }
 425         if (flags & EXT2_FLAG_SUPER_ONLY)
 426                 goto skip_read_bg;
 427         retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
 428                                 &fs->group_desc);
 429         if (retval)
 430                 goto cleanup;
 431         if (!group_block)
 432                 group_block = fs->super->s_first_data_block;
 433         /*
 434          * On a FS with a 1K blocksize, block 0 is reserved for bootloaders
 435          * so we must increment block numbers to any group 0 items.
 436          *
 437          * However, we cannot touch group_block directly because in the meta_bg
 438          * case, the ext2fs_descriptor_block_loc2() function will interpret
 439          * group_block != s_first_data_block to mean that we want to access the
 440          * backup group descriptors.  This is not what we want if the caller
 441          * set superblock == 0 (i.e. auto-detect the superblock), which is
 442          * what's going on here.
 443          */
 444         if (group_block == 0 && fs->blocksize == 1024)
 445                 group_zero_adjust = 1;
 446         dest = (char *) fs->group_desc;
 447 #ifdef WORDS_BIGENDIAN
 448         groups_per_block = EXT2_DESC_PER_BLOCK(fs->super);
 449 #endif
 450         if (ext2fs_has_feature_meta_bg(fs->super) &&
 451             !(flags & EXT2_FLAG_IMAGE_FILE)) {
 452                 first_meta_bg = fs->super->s_first_meta_bg;
 453                 if (first_meta_bg > fs->desc_blocks)
 454                         first_meta_bg = fs->desc_blocks;
 455         } else
 456                 first_meta_bg = fs->desc_blocks;
 457         if (first_meta_bg) {
 458                 retval = io_channel_read_blk(fs->io, group_block +
 459                                              group_zero_adjust + 1,
 460                                              first_meta_bg, dest);
 461                 if (retval)
 462                         goto cleanup;
 463 #ifdef WORDS_BIGENDIAN
 464                 gdp = (struct ext2_group_desc *) dest;
 465                 for (j=0; j < groups_per_block*first_meta_bg; j++) {
 466                         gdp = ext2fs_group_desc(fs, fs->group_desc, j);
 467                         if (gdp)
 468                                 ext2fs_swap_group_desc2(fs, gdp);
 469                 }
 470 #endif
 471                 dest += fs->blocksize*first_meta_bg;
 472         }
 473
 474         for (i = first_meta_bg ; i < fs->desc_blocks; i++) {
 475                 blk = ext2fs_descriptor_block_loc2(fs, group_block, i);
 476                 io_channel_cache_readahead(fs->io, blk, 1);
 477         }
 478
 479         for (i=first_meta_bg ; i < fs->desc_blocks; i++) {
 480                 blk = ext2fs_descriptor_block_loc2(fs, group_block, i);
 481                 retval = io_channel_read_blk64(fs->io, blk, 1, dest);
 482                 if (retval)
 483                         goto cleanup;
 484 #ifdef WORDS_BIGENDIAN
 485                 for (j=0; j < groups_per_block; j++) {
 486                         gdp = ext2fs_group_desc(fs, fs->group_desc,
 487                                                 i * groups_per_block + j);
 488                         if (gdp)
 489                                 ext2fs_swap_group_desc2(fs, gdp);
 490                 }
 491 #endif
 492                 dest += fs->blocksize;
 493         }
 494
 495         fs->stride = fs->super->s_raid_stride;
 496
 497         /*
 498          * If recovery is from backup superblock, Clear _UNININT flags &
 499          * reset bg_itable_unused to zero
 500          */
 501         if (superblock > 1 && ext2fs_has_group_desc_csum(fs)) {
 502                 dgrp_t group;
 503
 504                 for (group = 0; group < fs->group_desc_count; group++) {
 505                         ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
 506                         ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
 507                         ext2fs_bg_itable_unused_set(fs, group, 0);
 508                         /* The checksum will be reset later, but fix it here
 509                          * anyway to avoid printing a lot of spurious errors. */
 510                         ext2fs_group_desc_csum_set(fs, group);
 511                 }
 512                 if (fs->flags & EXT2_FLAG_RW)
 513                         ext2fs_mark_super_dirty(fs);
 514         }
 515 skip_read_bg:
 516         if (ext2fs_has_feature_mmp(fs->super) &&
 517             !(flags & EXT2_FLAG_SKIP_MMP) &&
 518             (flags & (EXT2_FLAG_RW | EXT2_FLAG_EXCLUSIVE))) {
 519                 retval = ext2fs_mmp_start(fs);
 520                 if (retval) {
 521                         fs->flags |= EXT2_FLAG_SKIP_MMP; /* just do cleanup */
 522                         ext2fs_mmp_stop(fs);
 523                         goto cleanup;
 524                 }
 525         }
 526
 527         if (fs->flags & EXT2_FLAG_SHARE_DUP) {
 528                 fs->block_sha_map = ext2fs_hashmap_create(ext2fs_djb2_hash,
 529                                         block_sha_map_free_entry, 4096);
 530                 if (!fs->block_sha_map) {
 531                         retval = EXT2_ET_NO_MEMORY;
 532                         goto cleanup;
 533                 }
 534                 ext2fs_set_feature_shared_blocks(fs->super);
 535         }
 536
 537         if (ext2fs_has_feature_casefold(fs->super))
 538                 fs->encoding = ext2fs_load_nls_table(fs->super->s_encoding);
 539
 540         fs->flags &= ~EXT2_FLAG_NOFREE_ON_ERROR;
 541         *ret_fs = fs;
 542
 543         return 0;
 544 cleanup:
 545         if (!(flags & EXT2_FLAG_NOFREE_ON_ERROR)) {
 546                 ext2fs_free(fs);
 547                 fs = NULL;
 548         }
 549         *ret_fs = fs;
 550         return retval;
 551 }
 552
 553 /*
 554  * Set/get the filesystem data I/O channel.
 555  *
 556  * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true.
 557  */
 558 errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io)
 559 {
 560         if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
 561                 return EXT2_ET_NOT_IMAGE_FILE;
 562         if (old_io) {
 563                 *old_io = (fs->image_io == fs->io) ? 0 : fs->io;
 564         }
 565         return 0;
 566 }
 567
 568 errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io)
 569 {
 570         if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
 571                 return EXT2_ET_NOT_IMAGE_FILE;
 572         fs->io = new_io ? new_io : fs->image_io;
 573         return 0;
 574 }
 575
 576 errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io)
 577 {
 578         errcode_t err;
 579
 580         if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
 581                 return EXT2_ET_NOT_IMAGE_FILE;
 582         err = io_channel_set_blksize(new_io, fs->blocksize);
 583         if (err)
 584                 return err;
 585         if ((new_io == fs->image_io) || (new_io == fs->io))
 586                 return 0;
 587         if ((fs->image_io != fs->io) &&
 588             fs->image_io)
 589                 io_channel_close(fs->image_io);
 590         if (fs->io)
 591                 io_channel_close(fs->io);
 592         fs->io = fs->image_io = new_io;
 593         fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW |
 594                 EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY;
 595         fs->flags &= ~EXT2_FLAG_IMAGE_FILE;
 596         return 0;
 597 }