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
 138         EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER);
 139
 140         retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
 141         if (retval)
 142                 return retval;
 143
 144         memset(fs, 0, sizeof(struct struct_ext2_filsys));
 145         fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
 146         fs->flags = flags;
 147         /* don't overwrite sb backups unless flag is explicitly cleared */
 148         fs->flags |= EXT2_FLAG_MASTER_SB_ONLY;
 149         fs->umask = 022;
 150
 151         time_env = getenv("E2FSPROGS_FAKE_TIME");
 152         if (time_env)
 153                 fs->now = strtoul(time_env, NULL, 0);
 154
 155         retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
 156         if (retval)
 157                 goto cleanup;
 158         strcpy(fs->device_name, name);
 159         cp = strchr(fs->device_name, '?');
 160         if (!io_options && cp) {
 161                 *cp++ = 0;
 162                 io_options = cp;
 163         }
 164
 165         io_flags = 0;
 166         if (flags & EXT2_FLAG_RW)
 167                 io_flags |= IO_FLAG_RW;
 168         if (flags & EXT2_FLAG_EXCLUSIVE)
 169                 io_flags |= IO_FLAG_EXCLUSIVE;
 170         if (flags & EXT2_FLAG_DIRECT_IO)
 171                 io_flags |= IO_FLAG_DIRECT_IO;
 172         retval = manager->open(fs->device_name, io_flags, &fs->io);
 173         if (retval)
 174                 goto cleanup;
 175         if (io_options &&
 176             (retval = io_channel_set_options(fs->io, io_options)))
 177                 goto cleanup;
 178         fs->image_io = fs->io;
 179         fs->io->app_data = fs;
 180         retval = io_channel_alloc_buf(fs->io, -SUPERBLOCK_SIZE, &fs->super);
 181         if (retval)
 182                 goto cleanup;
 183         if (flags & EXT2_FLAG_IMAGE_FILE) {
 184                 retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr),
 185                                         &fs->image_header);
 186                 if (retval)
 187                         goto cleanup;
 188                 retval = io_channel_read_blk(fs->io, 0,
 189                                              -(int)sizeof(struct ext2_image_hdr),
 190                                              fs->image_header);
 191                 if (retval)
 192                         goto cleanup;
 193                 if (ext2fs_le32_to_cpu(fs->image_header->magic_number) != EXT2_ET_MAGIC_E2IMAGE)
 194                         return EXT2_ET_MAGIC_E2IMAGE;
 195                 superblock = 1;
 196                 block_size = ext2fs_le32_to_cpu(fs->image_header->fs_blocksize);
 197         }
 198
 199         /*
 200          * If the user specifies a specific block # for the
 201          * superblock, then he/she must also specify the block size!
 202          * Otherwise, read the master superblock located at offset
 203          * SUPERBLOCK_OFFSET from the start of the partition.
 204          *
 205          * Note: we only save a backup copy of the superblock if we
 206          * are reading the superblock from the primary superblock location.
 207          */
 208         if (superblock) {
 209                 if (!block_size) {
 210                         retval = EXT2_ET_INVALID_ARGUMENT;
 211                         goto cleanup;
 212                 }
 213                 io_channel_set_blksize(fs->io, block_size);
 214                 group_block = superblock;
 215                 fs->orig_super = 0;
 216         } else {
 217                 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
 218                 superblock = 1;
 219                 group_block = 0;
 220                 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super);
 221                 if (retval)
 222                         goto cleanup;
 223         }
 224         retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE,
 225                                      fs->super);
 226         if (retval)
 227                 goto cleanup;
 228         if (fs->orig_super)
 229                 memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE);
 230
 231         if (!(fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS)) {
 232                 retval = 0;
 233                 if (!ext2fs_verify_csum_type(fs, fs->super))
 234                         retval = EXT2_ET_UNKNOWN_CSUM;
 235                 if (!ext2fs_superblock_csum_verify(fs, fs->super))
 236                         retval = EXT2_ET_SB_CSUM_INVALID;
 237         }
 238
 239 #ifdef WORDS_BIGENDIAN
 240         fs->flags |= EXT2_FLAG_SWAP_BYTES;
 241         ext2fs_swap_super(fs->super);
 242 #else
 243         if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
 244                 retval = EXT2_ET_UNIMPLEMENTED;
 245                 goto cleanup;
 246         }
 247 #endif
 248
 249         if (fs->super->s_magic != EXT2_SUPER_MAGIC)
 250                 retval = EXT2_ET_BAD_MAGIC;
 251         if (retval)
 252                 goto cleanup;
 253
 254         if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) {
 255                 retval = EXT2_ET_REV_TOO_HIGH;
 256                 goto cleanup;
 257         }
 258
 259         /*
 260          * Check for feature set incompatibility
 261          */
 262         if (!(flags & EXT2_FLAG_FORCE)) {
 263                 features = fs->super->s_feature_incompat;
 264 #ifdef EXT2_LIB_SOFTSUPP_INCOMPAT
 265                 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
 266                         features &= ~EXT2_LIB_SOFTSUPP_INCOMPAT;
 267 #endif
 268                 if (features & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
 269                         retval = EXT2_ET_UNSUPP_FEATURE;
 270                         goto cleanup;
 271                 }
 272
 273                 features = fs->super->s_feature_ro_compat;
 274 #ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT
 275                 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
 276                         features &= ~EXT2_LIB_SOFTSUPP_RO_COMPAT;
 277 #endif
 278                 if ((flags & EXT2_FLAG_RW) &&
 279                     (features & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) {
 280                         retval = EXT2_ET_RO_UNSUPP_FEATURE;
 281                         goto cleanup;
 282                 }
 283
 284                 if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) &&
 285                     ext2fs_has_feature_journal_dev(fs->super)) {
 286                         retval = EXT2_ET_UNSUPP_FEATURE;
 287                         goto cleanup;
 288                 }
 289         }
 290
 291         if (fs->super->s_log_block_size >
 292             (unsigned) (EXT2_MAX_BLOCK_LOG_SIZE - EXT2_MIN_BLOCK_LOG_SIZE)) {
 293                 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
 294                 goto cleanup;
 295         }
 296
 297         /*
 298          * bigalloc requires cluster-aware bitfield operations, which at the
 299          * moment means we need EXT2_FLAG_64BITS.
 300          */
 301         if (ext2fs_has_feature_bigalloc(fs->super) &&
 302             !(flags & EXT2_FLAG_64BITS)) {
 303                 retval = EXT2_ET_CANT_USE_LEGACY_BITMAPS;
 304                 goto cleanup;
 305         }
 306
 307         if (!ext2fs_has_feature_bigalloc(fs->super) &&
 308             (fs->super->s_log_block_size != fs->super->s_log_cluster_size)) {
 309                 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
 310                 goto cleanup;
 311         }
 312         fs->fragsize = fs->blocksize = EXT2_BLOCK_SIZE(fs->super);
 313         inode_size = EXT2_INODE_SIZE(fs->super);
 314         if ((inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 315             (inode_size > fs->blocksize) ||
 316             (inode_size & (inode_size - 1))) {
 317                 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
 318                 goto cleanup;
 319         }
 320
 321         /* Enforce the block group descriptor size */
 322         if (ext2fs_has_feature_64bit(fs->super)) {
 323                 if (fs->super->s_desc_size < EXT2_MIN_DESC_SIZE_64BIT) {
 324                         retval = EXT2_ET_BAD_DESC_SIZE;
 325                         goto cleanup;
 326                 }
 327         }
 328
 329         fs->cluster_ratio_bits = fs->super->s_log_cluster_size -
 330                 fs->super->s_log_block_size;
 331         if (EXT2_BLOCKS_PER_GROUP(fs->super) !=
 332             EXT2_CLUSTERS_PER_GROUP(fs->super) << fs->cluster_ratio_bits) {
 333                 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
 334                 goto cleanup;
 335         }
 336         fs->inode_blocks_per_group = ((EXT2_INODES_PER_GROUP(fs->super) *
 337                                        EXT2_INODE_SIZE(fs->super) +
 338                                        EXT2_BLOCK_SIZE(fs->super) - 1) /
 339                                       EXT2_BLOCK_SIZE(fs->super));
 340         if (block_size) {
 341                 if (block_size != fs->blocksize) {
 342                         retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE;
 343                         goto cleanup;
 344                 }
 345         }
 346         /*
 347          * Set the blocksize to the filesystem's blocksize.
 348          */
 349         io_channel_set_blksize(fs->io, fs->blocksize);
 350
 351         /*
 352          * If this is an external journal device, don't try to read
 353          * the group descriptors, because they're not there.
 354          */
 355         if (ext2fs_has_feature_journal_dev(fs->super)) {
 356                 fs->group_desc_count = 0;
 357                 *ret_fs = fs;
 358                 return 0;
 359         }
 360
 361         if (EXT2_INODES_PER_GROUP(fs->super) == 0) {
 362                 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
 363                 goto cleanup;
 364         }
 365         /* Precompute the FS UUID to seed other checksums */
 366         ext2fs_init_csum_seed(fs);
 367
 368         /*
 369          * Read group descriptors
 370          */
 371         blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super);
 372         if (blocks_per_group == 0 ||
 373             blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) ||
 374             fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super) ||
 375            EXT2_DESC_PER_BLOCK(fs->super) == 0 ||
 376            fs->super->s_first_data_block >= ext2fs_blocks_count(fs->super)) {
 377                 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
 378                 goto cleanup;
 379         }
 380         groups_cnt = ext2fs_div64_ceil(ext2fs_blocks_count(fs->super) -
 381                                        fs->super->s_first_data_block,
 382                                        blocks_per_group);
 383         if (groups_cnt >> 32) {
 384                 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
 385                 goto cleanup;
 386         }
 387         fs->group_desc_count =  groups_cnt;
 388         if (!(flags & EXT2_FLAG_IGNORE_SB_ERRORS) &&
 389             (__u64)fs->group_desc_count * EXT2_INODES_PER_GROUP(fs->super) !=
 390             fs->super->s_inodes_count) {
 391                 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
 392                 goto cleanup;
 393         }
 394         fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
 395                                           EXT2_DESC_PER_BLOCK(fs->super));
 396         retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
 397                                 &fs->group_desc);
 398         if (retval)
 399                 goto cleanup;
 400         if (!group_block)
 401                 group_block = fs->super->s_first_data_block;
 402         /*
 403          * On a FS with a 1K blocksize, block 0 is reserved for bootloaders
 404          * so we must increment block numbers to any group 0 items.
 405          *
 406          * However, we cannot touch group_block directly because in the meta_bg
 407          * case, the ext2fs_descriptor_block_loc2() function will interpret
 408          * group_block != s_first_data_block to mean that we want to access the
 409          * backup group descriptors.  This is not what we want if the caller
 410          * set superblock == 0 (i.e. auto-detect the superblock), which is
 411          * what's going on here.
 412          */
 413         if (group_block == 0 && fs->blocksize == 1024)
 414                 group_zero_adjust = 1;
 415         dest = (char *) fs->group_desc;
 416 #ifdef WORDS_BIGENDIAN
 417         groups_per_block = EXT2_DESC_PER_BLOCK(fs->super);
 418 #endif
 419         if (ext2fs_has_feature_meta_bg(fs->super) &&
 420             !(flags & EXT2_FLAG_IMAGE_FILE)) {
 421                 first_meta_bg = fs->super->s_first_meta_bg;
 422                 if (first_meta_bg > fs->desc_blocks)
 423                         first_meta_bg = fs->desc_blocks;
 424         } else
 425                 first_meta_bg = fs->desc_blocks;
 426         if (first_meta_bg) {
 427                 retval = io_channel_read_blk(fs->io, group_block +
 428                                              group_zero_adjust + 1,
 429                                              first_meta_bg, dest);
 430                 if (retval)
 431                         goto cleanup;
 432 #ifdef WORDS_BIGENDIAN
 433                 gdp = (struct ext2_group_desc *) dest;
 434                 for (j=0; j < groups_per_block*first_meta_bg; j++) {
 435                         gdp = ext2fs_group_desc(fs, fs->group_desc, j);
 436                         ext2fs_swap_group_desc2(fs, gdp);
 437                 }
 438 #endif
 439                 dest += fs->blocksize*first_meta_bg;
 440         }
 441
 442         for (i = first_meta_bg ; i < fs->desc_blocks; i++) {
 443                 blk = ext2fs_descriptor_block_loc2(fs, group_block, i);
 444                 io_channel_cache_readahead(fs->io, blk, 1);
 445         }
 446
 447         for (i=first_meta_bg ; i < fs->desc_blocks; i++) {
 448                 blk = ext2fs_descriptor_block_loc2(fs, group_block, i);
 449                 retval = io_channel_read_blk64(fs->io, blk, 1, dest);
 450                 if (retval)
 451                         goto cleanup;
 452 #ifdef WORDS_BIGENDIAN
 453                 for (j=0; j < groups_per_block; j++) {
 454                         gdp = ext2fs_group_desc(fs, fs->group_desc,
 455                                                 i * groups_per_block + j);
 456                         ext2fs_swap_group_desc2(fs, gdp);
 457                 }
 458 #endif
 459                 dest += fs->blocksize;
 460         }
 461
 462         fs->stride = fs->super->s_raid_stride;
 463
 464         /*
 465          * If recovery is from backup superblock, Clear _UNININT flags &
 466          * reset bg_itable_unused to zero
 467          */
 468         if (superblock > 1 && ext2fs_has_group_desc_csum(fs)) {
 469                 dgrp_t group;
 470
 471                 for (group = 0; group < fs->group_desc_count; group++) {
 472                         ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
 473                         ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
 474                         ext2fs_bg_itable_unused_set(fs, group, 0);
 475                         /* The checksum will be reset later, but fix it here
 476                          * anyway to avoid printing a lot of spurious errors. */
 477                         ext2fs_group_desc_csum_set(fs, group);
 478                 }
 479                 if (fs->flags & EXT2_FLAG_RW)
 480                         ext2fs_mark_super_dirty(fs);
 481         }
 482
 483         if (ext2fs_has_feature_mmp(fs->super) &&
 484             !(flags & EXT2_FLAG_SKIP_MMP) &&
 485             (flags & (EXT2_FLAG_RW | EXT2_FLAG_EXCLUSIVE))) {
 486                 retval = ext2fs_mmp_start(fs);
 487                 if (retval) {
 488                         fs->flags |= EXT2_FLAG_SKIP_MMP; /* just do cleanup */
 489                         ext2fs_mmp_stop(fs);
 490                         goto cleanup;
 491                 }
 492         }
 493
 494         if (fs->flags & EXT2_FLAG_SHARE_DUP) {
 495                 fs->block_sha_map = ext2fs_hashmap_create(ext2fs_djb2_hash,
 496                                         block_sha_map_free_entry, 4096);
 497                 if (!fs->block_sha_map) {
 498                         retval = EXT2_ET_NO_MEMORY;
 499                         goto cleanup;
 500                 }
 501                 ext2fs_set_feature_shared_blocks(fs->super);
 502         }
 503
 504         if (ext2fs_has_feature_fname_encoding(fs->super))
 505                 fs->encoding = ext2fs_load_nls_table(fs->super->s_encoding);
 506
 507         fs->flags &= ~EXT2_FLAG_NOFREE_ON_ERROR;
 508         *ret_fs = fs;
 509
 510         return 0;
 511 cleanup:
 512         if (!(flags & EXT2_FLAG_NOFREE_ON_ERROR)) {
 513                 ext2fs_free(fs);
 514                 fs = NULL;
 515         }
 516         *ret_fs = fs;
 517         return retval;
 518 }
 519
 520 /*
 521  * Set/get the filesystem data I/O channel.
 522  *
 523  * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true.
 524  */
 525 errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io)
 526 {
 527         if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
 528                 return EXT2_ET_NOT_IMAGE_FILE;
 529         if (old_io) {
 530                 *old_io = (fs->image_io == fs->io) ? 0 : fs->io;
 531         }
 532         return 0;
 533 }
 534
 535 errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io)
 536 {
 537         if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
 538                 return EXT2_ET_NOT_IMAGE_FILE;
 539         fs->io = new_io ? new_io : fs->image_io;
 540         return 0;
 541 }
 542
 543 errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io)
 544 {
 545         errcode_t err;
 546
 547         if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
 548                 return EXT2_ET_NOT_IMAGE_FILE;
 549         err = io_channel_set_blksize(new_io, fs->blocksize);
 550         if (err)
 551                 return err;
 552         if ((new_io == fs->image_io) || (new_io == fs->io))
 553                 return 0;
 554         if ((fs->image_io != fs->io) &&
 555             fs->image_io)
 556                 io_channel_close(fs->image_io);
 557         if (fs->io)
 558                 io_channel_close(fs->io);
 559         fs->io = fs->image_io = new_io;
 560         fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW |
 561                 EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY;
 562         fs->flags &= ~EXT2_FLAG_IMAGE_FILE;
 563         return 0;
 564 }