fs/ext2/super.c

   1 /*
   2  *  linux/fs/ext2/super.c
   3  *
   4  * Copyright (C) 1992, 1993, 1994, 1995
   5  * Remy Card (card@masi.ibp.fr)
   6  * Laboratoire MASI - Institut Blaise Pascal
   7  * Universite Pierre et Marie Curie (Paris VI)
   8  *
   9  *  from
  10  *
  11  *  linux/fs/minix/inode.c
  12  *
  13  *  Copyright (C) 1991, 1992  Linus Torvalds
  14  *
  15  *  Big-endian to little-endian byte-swapping/bitmaps by
  16  *        David S. Miller (davem@caip.rutgers.edu), 1995
  17  */
  18
  19 #include <linux/config.h>
  20 #include <linux/module.h>
  21 #include <linux/string.h>
  22 #include <linux/fs.h>
  23 #include <linux/ext2_fs.h>
  24 #include <linux/slab.h>
  25 #include <linux/init.h>
  26 #include <linux/locks.h>
  27 #include <linux/blkdev.h>
  28 #include <asm/uaccess.h>
  29
  30
  31 static void ext2_sync_super(struct super_block *sb,
  32                             struct ext2_super_block *es);
  33
  34 static char error_buf[1024];
  35
  36 void ext2_error (struct super_block * sb, const char * function,
  37                  const char * fmt, ...)
  38 {
  39         va_list args;
  40         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
  41
  42         if (!(sb->s_flags & MS_RDONLY)) {
  43                 sb->u.ext2_sb.s_mount_state |= EXT2_ERROR_FS;
  44                 es->s_state =
  45                         cpu_to_le16(le16_to_cpu(es->s_state) | EXT2_ERROR_FS);
  46                 ext2_sync_super(sb, es);
  47         }
  48         va_start (args, fmt);
  49         vsprintf (error_buf, fmt, args);
  50         va_end (args);
  51         if (test_opt (sb, ERRORS_PANIC) ||
  52             (le16_to_cpu(sb->u.ext2_sb.s_es->s_errors) == EXT2_ERRORS_PANIC &&
  53              !test_opt (sb, ERRORS_CONT) && !test_opt (sb, ERRORS_RO)))
  54                 panic ("EXT2-fs panic (device %s): %s: %s\n",
  55                        bdevname(sb->s_dev), function, error_buf);
  56         printk (KERN_CRIT "EXT2-fs error (device %s): %s: %s\n",
  57                 bdevname(sb->s_dev), function, error_buf);
  58         if (test_opt (sb, ERRORS_RO) ||
  59             (le16_to_cpu(sb->u.ext2_sb.s_es->s_errors) == EXT2_ERRORS_RO &&
  60              !test_opt (sb, ERRORS_CONT) && !test_opt (sb, ERRORS_PANIC))) {
  61                 printk ("Remounting filesystem read-only\n");
  62                 sb->s_flags |= MS_RDONLY;
  63         }
  64 }
  65
  66 NORET_TYPE void ext2_panic (struct super_block * sb, const char * function,
  67                             const char * fmt, ...)
  68 {
  69         va_list args;
  70
  71         if (!(sb->s_flags & MS_RDONLY)) {
  72                 sb->u.ext2_sb.s_mount_state |= EXT2_ERROR_FS;
  73                 sb->u.ext2_sb.s_es->s_state =
  74                         cpu_to_le16(le16_to_cpu(sb->u.ext2_sb.s_es->s_state) | EXT2_ERROR_FS);
  75                 mark_buffer_dirty(sb->u.ext2_sb.s_sbh);
  76                 sb->s_dirt = 1;
  77         }
  78         va_start (args, fmt);
  79         vsprintf (error_buf, fmt, args);
  80         va_end (args);
  81         sb->s_flags |= MS_RDONLY;
  82         panic ("EXT2-fs panic (device %s): %s: %s\n",
  83                bdevname(sb->s_dev), function, error_buf);
  84 }
  85
  86 void ext2_warning (struct super_block * sb, const char * function,
  87                    const char * fmt, ...)
  88 {
  89         va_list args;
  90
  91         va_start (args, fmt);
  92         vsprintf (error_buf, fmt, args);
  93         va_end (args);
  94         printk (KERN_WARNING "EXT2-fs warning (device %s): %s: %s\n",
  95                 bdevname(sb->s_dev), function, error_buf);
  96 }
  97
  98 void ext2_update_dynamic_rev(struct super_block *sb)
  99 {
 100         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
 101
 102         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
 103                 return;
 104
 105         ext2_warning(sb, __FUNCTION__,
 106                      "updating to rev %d because of new feature flag, "
 107                      "running e2fsck is recommended",
 108                      EXT2_DYNAMIC_REV);
 109
 110         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
 111         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
 112         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
 113         /* leave es->s_feature_*compat flags alone */
 114         /* es->s_uuid will be set by e2fsck if empty */
 115
 116         /*
 117          * The rest of the superblock fields should be zero, and if not it
 118          * means they are likely already in use, so leave them alone.  We
 119          * can leave it up to e2fsck to clean up any inconsistencies there.
 120          */
 121 }
 122
 123 void ext2_put_super (struct super_block * sb)
 124 {
 125         int db_count;
 126         int i;
 127
 128         if (!(sb->s_flags & MS_RDONLY)) {
 129                 struct ext2_super_block *es = EXT2_SB(sb)->s_es;
 130
 131                 es->s_state = le16_to_cpu(EXT2_SB(sb)->s_mount_state);
 132                 ext2_sync_super(sb, es);
 133         }
 134         db_count = EXT2_SB(sb)->s_gdb_count;
 135         for (i = 0; i < db_count; i++)
 136                 if (sb->u.ext2_sb.s_group_desc[i])
 137                         brelse (sb->u.ext2_sb.s_group_desc[i]);
 138         kfree(sb->u.ext2_sb.s_group_desc);
 139         for (i = 0; i < EXT2_MAX_GROUP_LOADED; i++)
 140                 if (sb->u.ext2_sb.s_inode_bitmap[i])
 141                         brelse (sb->u.ext2_sb.s_inode_bitmap[i]);
 142         for (i = 0; i < EXT2_MAX_GROUP_LOADED; i++)
 143                 if (sb->u.ext2_sb.s_block_bitmap[i])
 144                         brelse (sb->u.ext2_sb.s_block_bitmap[i]);
 145         brelse (sb->u.ext2_sb.s_sbh);
 146
 147         return;
 148 }
 149
 150 static struct super_operations ext2_sops = {
 151         read_inode:     ext2_read_inode,
 152         write_inode:    ext2_write_inode,
 153         put_inode:      ext2_put_inode,
 154         delete_inode:   ext2_delete_inode,
 155         put_super:      ext2_put_super,
 156         write_super:    ext2_write_super,
 157         statfs:         ext2_statfs,
 158         remount_fs:     ext2_remount,
 159 };
 160
 161 /*
 162  * This function has been shamelessly adapted from the msdos fs
 163  */
 164 static int parse_options (char * options, unsigned long * sb_block,
 165                           unsigned short *resuid, unsigned short * resgid,
 166                           unsigned long * mount_options)
 167 {
 168         char * this_char;
 169         char * value;
 170
 171         if (!options)
 172                 return 1;
 173         for (this_char = strtok (options, ",");
 174              this_char != NULL;
 175              this_char = strtok (NULL, ",")) {
 176                 if ((value = strchr (this_char, '=')) != NULL)
 177                         *value++ = 0;
 178                 if (!strcmp (this_char, "bsddf"))
 179                         clear_opt (*mount_options, MINIX_DF);
 180                 else if (!strcmp (this_char, "nouid32")) {
 181                         set_opt (*mount_options, NO_UID32);
 182                 }
 183                 else if (!strcmp (this_char, "check")) {
 184                         if (!value || !*value || !strcmp (value, "none"))
 185                                 clear_opt (*mount_options, CHECK);
 186                         else
 187 #ifdef CONFIG_EXT2_CHECK
 188                                 set_opt (*mount_options, CHECK);
 189 #else
 190                                 printk("EXT2 Check option not supported\n");
 191 #endif
 192                 }
 193                 else if (!strcmp (this_char, "debug"))
 194                         set_opt (*mount_options, DEBUG);
 195                 else if (!strcmp (this_char, "errors")) {
 196                         if (!value || !*value) {
 197                                 printk ("EXT2-fs: the errors option requires "
 198                                         "an argument\n");
 199                                 return 0;
 200                         }
 201                         if (!strcmp (value, "continue")) {
 202                                 clear_opt (*mount_options, ERRORS_RO);
 203                                 clear_opt (*mount_options, ERRORS_PANIC);
 204                                 set_opt (*mount_options, ERRORS_CONT);
 205                         }
 206                         else if (!strcmp (value, "remount-ro")) {
 207                                 clear_opt (*mount_options, ERRORS_CONT);
 208                                 clear_opt (*mount_options, ERRORS_PANIC);
 209                                 set_opt (*mount_options, ERRORS_RO);
 210                         }
 211                         else if (!strcmp (value, "panic")) {
 212                                 clear_opt (*mount_options, ERRORS_CONT);
 213                                 clear_opt (*mount_options, ERRORS_RO);
 214                                 set_opt (*mount_options, ERRORS_PANIC);
 215                         }
 216                         else {
 217                                 printk ("EXT2-fs: Invalid errors option: %s\n",
 218                                         value);
 219                                 return 0;
 220                         }
 221                 }
 222                 else if (!strcmp (this_char, "grpid") ||
 223                          !strcmp (this_char, "bsdgroups"))
 224                         set_opt (*mount_options, GRPID);
 225                 else if (!strcmp (this_char, "minixdf"))
 226                         set_opt (*mount_options, MINIX_DF);
 227                 else if (!strcmp (this_char, "nocheck"))
 228                         clear_opt (*mount_options, CHECK);
 229                 else if (!strcmp (this_char, "nogrpid") ||
 230                          !strcmp (this_char, "sysvgroups"))
 231                         clear_opt (*mount_options, GRPID);
 232                 else if (!strcmp (this_char, "resgid")) {
 233                         if (!value || !*value) {
 234                                 printk ("EXT2-fs: the resgid option requires "
 235                                         "an argument\n");
 236                                 return 0;
 237                         }
 238                         *resgid = simple_strtoul (value, &value, 0);
 239                         if (*value) {
 240                                 printk ("EXT2-fs: Invalid resgid option: %s\n",
 241                                         value);
 242                                 return 0;
 243                         }
 244                 }
 245                 else if (!strcmp (this_char, "resuid")) {
 246                         if (!value || !*value) {
 247                                 printk ("EXT2-fs: the resuid option requires "
 248                                         "an argument");
 249                                 return 0;
 250                         }
 251                         *resuid = simple_strtoul (value, &value, 0);
 252                         if (*value) {
 253                                 printk ("EXT2-fs: Invalid resuid option: %s\n",
 254                                         value);
 255                                 return 0;
 256                         }
 257                 }
 258                 else if (!strcmp (this_char, "sb")) {
 259                         if (!value || !*value) {
 260                                 printk ("EXT2-fs: the sb option requires "
 261                                         "an argument");
 262                                 return 0;
 263                         }
 264                         *sb_block = simple_strtoul (value, &value, 0);
 265                         if (*value) {
 266                                 printk ("EXT2-fs: Invalid sb option: %s\n",
 267                                         value);
 268                                 return 0;
 269                         }
 270                 }
 271                 /* Silently ignore the quota options */
 272                 else if (!strcmp (this_char, "grpquota")
 273                          || !strcmp (this_char, "noquota")
 274                          || !strcmp (this_char, "quota")
 275                          || !strcmp (this_char, "usrquota"))
 276                         /* Don't do anything ;-) */ ;
 277                 else {
 278                         printk ("EXT2-fs: Unrecognized mount option %s\n", this_char);
 279                         return 0;
 280                 }
 281         }
 282         return 1;
 283 }
 284
 285 static int ext2_setup_super (struct super_block * sb,
 286                               struct ext2_super_block * es,
 287                               int read_only)
 288 {
 289         int res = 0;
 290         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 291                 printk ("EXT2-fs warning: revision level too high, "
 292                         "forcing read-only mode\n");
 293                 res = MS_RDONLY;
 294         }
 295         if (read_only)
 296                 return res;
 297         if (!(sb->u.ext2_sb.s_mount_state & EXT2_VALID_FS))
 298                 printk ("EXT2-fs warning: mounting unchecked fs, "
 299                         "running e2fsck is recommended\n");
 300         else if ((sb->u.ext2_sb.s_mount_state & EXT2_ERROR_FS))
 301                 printk ("EXT2-fs warning: mounting fs with errors, "
 302                         "running e2fsck is recommended\n");
 303         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 304                  le16_to_cpu(es->s_mnt_count) >=
 305                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 306                 printk ("EXT2-fs warning: maximal mount count reached, "
 307                         "running e2fsck is recommended\n");
 308         else if (le32_to_cpu(es->s_checkinterval) &&
 309                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= CURRENT_TIME))
 310                 printk ("EXT2-fs warning: checktime reached, "
 311                         "running e2fsck is recommended\n");
 312         if (!(__s16) le16_to_cpu(es->s_max_mnt_count))
 313                 es->s_max_mnt_count = (__s16) cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 314         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
 315         ext2_write_super(sb);
 316         if (test_opt (sb, DEBUG))
 317                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
 318                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
 319                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 320                         sb->u.ext2_sb.s_frag_size,
 321                         sb->u.ext2_sb.s_groups_count,
 322                         EXT2_BLOCKS_PER_GROUP(sb),
 323                         EXT2_INODES_PER_GROUP(sb),
 324                         sb->u.ext2_sb.s_mount_opt);
 325 #ifdef CONFIG_EXT2_CHECK
 326         if (test_opt (sb, CHECK)) {
 327                 ext2_check_blocks_bitmap (sb);
 328                 ext2_check_inodes_bitmap (sb);
 329         }
 330 #endif
 331         return res;
 332 }
 333
 334 static int ext2_check_descriptors (struct super_block * sb)
 335 {
 336         int i;
 337         int desc_block = 0;
 338         unsigned long block = le32_to_cpu(sb->u.ext2_sb.s_es->s_first_data_block);
 339         struct ext2_group_desc * gdp = NULL;
 340
 341         ext2_debug ("Checking group descriptors");
 342
 343         for (i = 0; i < sb->u.ext2_sb.s_groups_count; i++)
 344         {
 345                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
 346                         gdp = (struct ext2_group_desc *) sb->u.ext2_sb.s_group_desc[desc_block++]->b_data;
 347                 if (le32_to_cpu(gdp->bg_block_bitmap) < block ||
 348                     le32_to_cpu(gdp->bg_block_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 349                 {
 350                         ext2_error (sb, "ext2_check_descriptors",
 351                                     "Block bitmap for group %d"
 352                                     " not in group (block %lu)!",
 353                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 354                         return 0;
 355                 }
 356                 if (le32_to_cpu(gdp->bg_inode_bitmap) < block ||
 357                     le32_to_cpu(gdp->bg_inode_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 358                 {
 359                         ext2_error (sb, "ext2_check_descriptors",
 360                                     "Inode bitmap for group %d"
 361                                     " not in group (block %lu)!",
 362                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 363                         return 0;
 364                 }
 365                 if (le32_to_cpu(gdp->bg_inode_table) < block ||
 366                     le32_to_cpu(gdp->bg_inode_table) + sb->u.ext2_sb.s_itb_per_group >=
 367                     block + EXT2_BLOCKS_PER_GROUP(sb))
 368                 {
 369                         ext2_error (sb, "ext2_check_descriptors",
 370                                     "Inode table for group %d"
 371                                     " not in group (block %lu)!",
 372                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 373                         return 0;
 374                 }
 375                 block += EXT2_BLOCKS_PER_GROUP(sb);
 376                 gdp++;
 377         }
 378         return 1;
 379 }
 380
 381 #define log2(n) ffz(~(n))
 382
 383 /*
 384  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 385  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 386  * We need to be 1 filesystem block less than the 2^32 sector limit.
 387  */
 388 static loff_t ext2_max_size(int bits)
 389 {
 390         loff_t res = EXT2_NDIR_BLOCKS;
 391         res += 1LL << (bits-2);
 392         res += 1LL << (2*(bits-2));
 393         res += 1LL << (3*(bits-2));
 394         res <<= bits;
 395         if (res > (512LL << 32) - (1 << bits))
 396                 res = (512LL << 32) - (1 << bits);
 397         return res;
 398 }
 399
 400 struct super_block * ext2_read_super (struct super_block * sb, void * data,
 401                                       int silent)
 402 {
 403         struct buffer_head * bh;
 404         struct ext2_super_block * es;
 405         unsigned long sb_block = 1;
 406         unsigned short resuid = EXT2_DEF_RESUID;
 407         unsigned short resgid = EXT2_DEF_RESGID;
 408         unsigned long logic_sb_block = 1;
 409         unsigned long offset = 0;
 410         kdev_t dev = sb->s_dev;
 411         int blocksize = BLOCK_SIZE;
 412         int db_count;
 413         int i, j;
 414
 415         /*
 416          * See what the current blocksize for the device is, and
 417          * use that as the blocksize.  Otherwise (or if the blocksize
 418          * is smaller than the default) use the default.
 419          * This is important for devices that have a hardware
 420          * sectorsize that is larger than the default.
 421          */
 422         blocksize = get_hardsect_size(dev);
 423         if(blocksize < BLOCK_SIZE )
 424             blocksize = BLOCK_SIZE;
 425
 426         sb->u.ext2_sb.s_mount_opt = 0;
 427         if (!parse_options ((char *) data, &sb_block, &resuid, &resgid,
 428             &sb->u.ext2_sb.s_mount_opt)) {
 429                 return NULL;
 430         }
 431
 432         if (set_blocksize(dev, blocksize) < 0) {
 433                 printk ("EXT2-fs: unable to set blocksize %d\n", blocksize);
 434                 return NULL;
 435         }
 436         sb->s_blocksize = blocksize;
 437
 438         /*
 439          * If the superblock doesn't start on a sector boundary,
 440          * calculate the offset.  FIXME(eric) this doesn't make sense
 441          * that we would have to do this.
 442          */
 443         if (blocksize != BLOCK_SIZE) {
 444                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 445                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 446         }
 447
 448         if (!(bh = sb_bread(sb, logic_sb_block))) {
 449                 printk ("EXT2-fs: unable to read superblock\n");
 450                 return NULL;
 451         }
 452         /*
 453          * Note: s_es must be initialized as soon as possible because
 454          *       some ext2 macro-instructions depend on its value
 455          */
 456         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 457         sb->u.ext2_sb.s_es = es;
 458         sb->s_magic = le16_to_cpu(es->s_magic);
 459         if (sb->s_magic != EXT2_SUPER_MAGIC) {
 460                 if (!silent)
 461                         printk ("VFS: Can't find ext2 filesystem on dev %s.\n",
 462                                 bdevname(dev));
 463                 goto failed_mount;
 464         }
 465         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 466             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 467              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 468              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 469                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
 470                        "running e2fsck is recommended\n");
 471         /*
 472          * Check feature flags regardless of the revision level, since we
 473          * previously didn't change the revision level when setting the flags,
 474          * so there is a chance incompat flags are set on a rev 0 filesystem.
 475          */
 476         if ((i = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP))) {
 477                 printk("EXT2-fs: %s: couldn't mount because of "
 478                        "unsupported optional features (%x).\n",
 479                        bdevname(dev), i);
 480                 goto failed_mount;
 481         }
 482         if (!(sb->s_flags & MS_RDONLY) &&
 483             (i = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 484                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
 485                        "unsupported optional features (%x).\n",
 486                        bdevname(dev), i);
 487                 goto failed_mount;
 488         }
 489         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 490                 ext2_warning(sb, __FUNCTION__,
 491                         "mounting ext3 filesystem as ext2\n");
 492         sb->s_blocksize_bits =
 493                 le32_to_cpu(EXT2_SB(sb)->s_es->s_log_block_size) + 10;
 494         sb->s_blocksize = 1 << sb->s_blocksize_bits;
 495
 496         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 497
 498         /* If the blocksize doesn't match, re-read the thing.. */
 499         if (sb->s_blocksize != blocksize) {
 500                 blocksize = sb->s_blocksize;
 501                 brelse(bh);
 502
 503                 if (set_blocksize(dev, blocksize) < 0) {
 504                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
 505                         return NULL;
 506                 }
 507
 508                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 509                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 510                 bh = sb_bread(sb, logic_sb_block);
 511                 if(!bh) {
 512                         printk("EXT2-fs: Couldn't read superblock on "
 513                                "2nd try.\n");
 514                         goto failed_mount;
 515                 }
 516                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 517                 sb->u.ext2_sb.s_es = es;
 518                 if (es->s_magic != le16_to_cpu(EXT2_SUPER_MAGIC)) {
 519                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
 520                         goto failed_mount;
 521                 }
 522         }
 523
 524         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 525                 sb->u.ext2_sb.s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 526                 sb->u.ext2_sb.s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 527         } else {
 528                 sb->u.ext2_sb.s_inode_size = le16_to_cpu(es->s_inode_size);
 529                 sb->u.ext2_sb.s_first_ino = le32_to_cpu(es->s_first_ino);
 530                 if (sb->u.ext2_sb.s_inode_size != EXT2_GOOD_OLD_INODE_SIZE) {
 531                         printk ("EXT2-fs: unsupported inode size: %d\n",
 532                                 sb->u.ext2_sb.s_inode_size);
 533                         goto failed_mount;
 534                 }
 535         }
 536         sb->u.ext2_sb.s_frag_size = EXT2_MIN_FRAG_SIZE <<
 537                                    le32_to_cpu(es->s_log_frag_size);
 538         if (sb->u.ext2_sb.s_frag_size)
 539                 sb->u.ext2_sb.s_frags_per_block = sb->s_blocksize /
 540                                                   sb->u.ext2_sb.s_frag_size;
 541         else
 542                 sb->s_magic = 0;
 543         sb->u.ext2_sb.s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 544         sb->u.ext2_sb.s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 545         sb->u.ext2_sb.s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 546         sb->u.ext2_sb.s_inodes_per_block = sb->s_blocksize /
 547                                            EXT2_INODE_SIZE(sb);
 548         sb->u.ext2_sb.s_itb_per_group = sb->u.ext2_sb.s_inodes_per_group /
 549                                         sb->u.ext2_sb.s_inodes_per_block;
 550         sb->u.ext2_sb.s_desc_per_block = sb->s_blocksize /
 551                                          sizeof (struct ext2_group_desc);
 552         sb->u.ext2_sb.s_sbh = bh;
 553         if (resuid != EXT2_DEF_RESUID)
 554                 sb->u.ext2_sb.s_resuid = resuid;
 555         else
 556                 sb->u.ext2_sb.s_resuid = le16_to_cpu(es->s_def_resuid);
 557         if (resgid != EXT2_DEF_RESGID)
 558                 sb->u.ext2_sb.s_resgid = resgid;
 559         else
 560                 sb->u.ext2_sb.s_resgid = le16_to_cpu(es->s_def_resgid);
 561         sb->u.ext2_sb.s_mount_state = le16_to_cpu(es->s_state);
 562         sb->u.ext2_sb.s_addr_per_block_bits =
 563                 log2 (EXT2_ADDR_PER_BLOCK(sb));
 564         sb->u.ext2_sb.s_desc_per_block_bits =
 565                 log2 (EXT2_DESC_PER_BLOCK(sb));
 566         if (sb->s_magic != EXT2_SUPER_MAGIC) {
 567                 if (!silent)
 568                         printk ("VFS: Can't find an ext2 filesystem on dev "
 569                                 "%s.\n",
 570                                 bdevname(dev));
 571                 goto failed_mount;
 572         }
 573         if (sb->s_blocksize != bh->b_size) {
 574                 if (!silent)
 575                         printk ("VFS: Unsupported blocksize on dev "
 576                                 "%s.\n", bdevname(dev));
 577                 goto failed_mount;
 578         }
 579
 580         if (sb->s_blocksize != sb->u.ext2_sb.s_frag_size) {
 581                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
 582                         sb->u.ext2_sb.s_frag_size, sb->s_blocksize);
 583                 goto failed_mount;
 584         }
 585
 586         if (sb->u.ext2_sb.s_blocks_per_group > sb->s_blocksize * 8) {
 587                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
 588                         sb->u.ext2_sb.s_blocks_per_group);
 589                 goto failed_mount;
 590         }
 591         if (sb->u.ext2_sb.s_frags_per_group > sb->s_blocksize * 8) {
 592                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
 593                         sb->u.ext2_sb.s_frags_per_group);
 594                 goto failed_mount;
 595         }
 596         if (sb->u.ext2_sb.s_inodes_per_group > sb->s_blocksize * 8) {
 597                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
 598                         sb->u.ext2_sb.s_inodes_per_group);
 599                 goto failed_mount;
 600         }
 601
 602         sb->u.ext2_sb.s_groups_count = (le32_to_cpu(es->s_blocks_count) -
 603                                         le32_to_cpu(es->s_first_data_block) +
 604                                        EXT2_BLOCKS_PER_GROUP(sb) - 1) /
 605                                        EXT2_BLOCKS_PER_GROUP(sb);
 606         db_count = (sb->u.ext2_sb.s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
 607                    EXT2_DESC_PER_BLOCK(sb);
 608         sb->u.ext2_sb.s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
 609         if (sb->u.ext2_sb.s_group_desc == NULL) {
 610                 printk ("EXT2-fs: not enough memory\n");
 611                 goto failed_mount;
 612         }
 613         for (i = 0; i < db_count; i++) {
 614                 sb->u.ext2_sb.s_group_desc[i] = sb_bread(sb, logic_sb_block + i + 1);
 615                 if (!sb->u.ext2_sb.s_group_desc[i]) {
 616                         for (j = 0; j < i; j++)
 617                                 brelse (sb->u.ext2_sb.s_group_desc[j]);
 618                         kfree(sb->u.ext2_sb.s_group_desc);
 619                         printk ("EXT2-fs: unable to read group descriptors\n");
 620                         goto failed_mount;
 621                 }
 622         }
 623         if (!ext2_check_descriptors (sb)) {
 624                 printk ("EXT2-fs: group descriptors corrupted!\n");
 625                 db_count = i;
 626                 goto failed_mount2;
 627         }
 628         for (i = 0; i < EXT2_MAX_GROUP_LOADED; i++) {
 629                 sb->u.ext2_sb.s_inode_bitmap_number[i] = 0;
 630                 sb->u.ext2_sb.s_inode_bitmap[i] = NULL;
 631                 sb->u.ext2_sb.s_block_bitmap_number[i] = 0;
 632                 sb->u.ext2_sb.s_block_bitmap[i] = NULL;
 633         }
 634         sb->u.ext2_sb.s_loaded_inode_bitmaps = 0;
 635         sb->u.ext2_sb.s_loaded_block_bitmaps = 0;
 636         sb->u.ext2_sb.s_gdb_count = db_count;
 637         /*
 638          * set up enough so that it can read an inode
 639          */
 640         sb->s_op = &ext2_sops;
 641         sb->s_root = d_alloc_root(iget(sb, EXT2_ROOT_INO));
 642         if (!sb->s_root || !S_ISDIR(sb->s_root->d_inode->i_mode) ||
 643             !sb->s_root->d_inode->i_blocks || !sb->s_root->d_inode->i_size) {
 644                 if (sb->s_root) {
 645                         dput(sb->s_root);
 646                         sb->s_root = NULL;
 647                         printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
 648                 } else
 649                         printk(KERN_ERR "EXT2-fs: get root inode failed\n");
 650                 goto failed_mount2;
 651         }
 652         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
 653         return sb;
 654 failed_mount2:
 655         for (i = 0; i < db_count; i++)
 656                 brelse(sb->u.ext2_sb.s_group_desc[i]);
 657         kfree(sb->u.ext2_sb.s_group_desc);
 658 failed_mount:
 659         brelse(bh);
 660         return NULL;
 661 }
 662
 663 static void ext2_commit_super (struct super_block * sb,
 664                                struct ext2_super_block * es)
 665 {
 666         es->s_wtime = cpu_to_le32(CURRENT_TIME);
 667         mark_buffer_dirty(sb->u.ext2_sb.s_sbh);
 668         sb->s_dirt = 0;
 669 }
 670
 671 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
 672 {
 673         es->s_wtime = cpu_to_le32(CURRENT_TIME);
 674         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 675         ll_rw_block(WRITE, 1, &EXT2_SB(sb)->s_sbh);
 676         wait_on_buffer(EXT2_SB(sb)->s_sbh);
 677         sb->s_dirt = 0;
 678 }
 679
 680 /*
 681  * In the second extended file system, it is not necessary to
 682  * write the super block since we use a mapping of the
 683  * disk super block in a buffer.
 684  *
 685  * However, this function is still used to set the fs valid
 686  * flags to 0.  We need to set this flag to 0 since the fs
 687  * may have been checked while mounted and e2fsck may have
 688  * set s_state to EXT2_VALID_FS after some corrections.
 689  */
 690
 691 void ext2_write_super (struct super_block * sb)
 692 {
 693         struct ext2_super_block * es;
 694
 695         if (!(sb->s_flags & MS_RDONLY)) {
 696                 es = sb->u.ext2_sb.s_es;
 697
 698                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
 699                         ext2_debug ("setting valid to 0\n");
 700                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
 701                                                   ~EXT2_VALID_FS);
 702                         es->s_mtime = cpu_to_le32(CURRENT_TIME);
 703                         ext2_sync_super(sb, es);
 704                 } else
 705                         ext2_commit_super (sb, es);
 706         }
 707         sb->s_dirt = 0;
 708 }
 709
 710 int ext2_remount (struct super_block * sb, int * flags, char * data)
 711 {
 712         struct ext2_super_block * es;
 713         unsigned short resuid = sb->u.ext2_sb.s_resuid;
 714         unsigned short resgid = sb->u.ext2_sb.s_resgid;
 715         unsigned long new_mount_opt;
 716         unsigned long tmp;
 717
 718         /*
 719          * Allow the "check" option to be passed as a remount option.
 720          */
 721         new_mount_opt = sb->u.ext2_sb.s_mount_opt;
 722         if (!parse_options (data, &tmp, &resuid, &resgid,
 723                             &new_mount_opt))
 724                 return -EINVAL;
 725
 726         sb->u.ext2_sb.s_mount_opt = new_mount_opt;
 727         sb->u.ext2_sb.s_resuid = resuid;
 728         sb->u.ext2_sb.s_resgid = resgid;
 729         es = sb->u.ext2_sb.s_es;
 730         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 731                 return 0;
 732         if (*flags & MS_RDONLY) {
 733                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
 734                     !(sb->u.ext2_sb.s_mount_state & EXT2_VALID_FS))
 735                         return 0;
 736                 /*
 737                  * OK, we are remounting a valid rw partition rdonly, so set
 738                  * the rdonly flag and then mark the partition as valid again.
 739                  */
 740                 es->s_state = cpu_to_le16(sb->u.ext2_sb.s_mount_state);
 741                 es->s_mtime = cpu_to_le32(CURRENT_TIME);
 742         } else {
 743                 int ret;
 744                 if ((ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
 745                                                ~EXT2_FEATURE_RO_COMPAT_SUPP))) {
 746                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
 747                                "unsupported optional features (%x).\n",
 748                                bdevname(sb->s_dev), ret);
 749                         return -EROFS;
 750                 }
 751                 /*
 752                  * Mounting a RDONLY partition read-write, so reread and
 753                  * store the current valid flag.  (It may have been changed
 754                  * by e2fsck since we originally mounted the partition.)
 755                  */
 756                 sb->u.ext2_sb.s_mount_state = le16_to_cpu(es->s_state);
 757                 if (!ext2_setup_super (sb, es, 0))
 758                         sb->s_flags &= ~MS_RDONLY;
 759         }
 760         ext2_sync_super(sb, es);
 761         return 0;
 762 }
 763
 764 int ext2_statfs (struct super_block * sb, struct statfs * buf)
 765 {
 766         unsigned long overhead;
 767         int i;
 768
 769         if (test_opt (sb, MINIX_DF))
 770                 overhead = 0;
 771         else {
 772                 /*
 773                  * Compute the overhead (FS structures)
 774                  */
 775
 776                 /*
 777                  * All of the blocks before first_data_block are
 778                  * overhead
 779                  */
 780                 overhead = le32_to_cpu(sb->u.ext2_sb.s_es->s_first_data_block);
 781
 782                 /*
 783                  * Add the overhead attributed to the superblock and
 784                  * block group descriptors.  If the sparse superblocks
 785                  * feature is turned on, then not all groups have this.
 786                  */
 787                 for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++)
 788                         overhead += ext2_bg_has_super(sb, i) +
 789                                 ext2_bg_num_gdb(sb, i);
 790
 791                 /*
 792                  * Every block group has an inode bitmap, a block
 793                  * bitmap, and an inode table.
 794                  */
 795                 overhead += (sb->u.ext2_sb.s_groups_count *
 796                              (2 + sb->u.ext2_sb.s_itb_per_group));
 797         }
 798
 799         buf->f_type = EXT2_SUPER_MAGIC;
 800         buf->f_bsize = sb->s_blocksize;
 801         buf->f_blocks = le32_to_cpu(sb->u.ext2_sb.s_es->s_blocks_count) - overhead;
 802         buf->f_bfree = ext2_count_free_blocks (sb);
 803         buf->f_bavail = buf->f_bfree - le32_to_cpu(sb->u.ext2_sb.s_es->s_r_blocks_count);
 804         if (buf->f_bfree < le32_to_cpu(sb->u.ext2_sb.s_es->s_r_blocks_count))
 805                 buf->f_bavail = 0;
 806         buf->f_files = le32_to_cpu(sb->u.ext2_sb.s_es->s_inodes_count);
 807         buf->f_ffree = ext2_count_free_inodes (sb);
 808         buf->f_namelen = EXT2_NAME_LEN;
 809         return 0;
 810 }
 811
 812 static DECLARE_FSTYPE_DEV(ext2_fs_type, "ext2", ext2_read_super);
 813
 814 static int __init init_ext2_fs(void)
 815 {
 816         return register_filesystem(&ext2_fs_type);
 817 }
 818
 819 static void __exit exit_ext2_fs(void)
 820 {
 821         unregister_filesystem(&ext2_fs_type);
 822 }
 823
 824 EXPORT_NO_SYMBOLS;
 825
 826 module_init(init_ext2_fs)
 827 module_exit(exit_ext2_fs)