git.oblomov.eu Git - linux-2.6/blob - 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/slab.h>
  23 #include <linux/init.h>
  24 #include <linux/blkdev.h>
  25 #include <linux/parser.h>
  26 #include <linux/random.h>
  27 #include <linux/buffer_head.h>
  28 #include <linux/smp_lock.h>
  29 #include <linux/vfs.h>
  30 #include <asm/uaccess.h>
  31 #include "ext2.h"
  32 #include "xattr.h"
  33 #include "acl.h"
  34
  35 static void ext2_sync_super(struct super_block *sb,
  36                             struct ext2_super_block *es);
  37 static int ext2_remount (struct super_block * sb, int * flags, char * data);
  38 static int ext2_statfs (struct super_block * sb, struct kstatfs * buf);
  39
  40 void ext2_error (struct super_block * sb, const char * function,
  41                  const char * fmt, ...)
  42 {
  43         va_list args;
  44         struct ext2_sb_info *sbi = EXT2_SB(sb);
  45         struct ext2_super_block *es = sbi->s_es;
  46
  47         if (!(sb->s_flags & MS_RDONLY)) {
  48                 sbi->s_mount_state |= EXT2_ERROR_FS;
  49                 es->s_state =
  50                         cpu_to_le16(le16_to_cpu(es->s_state) | EXT2_ERROR_FS);
  51                 ext2_sync_super(sb, es);
  52         }
  53
  54         va_start(args, fmt);
  55         printk(KERN_CRIT "EXT2-fs error (device %s): %s: ",sb->s_id, function);
  56         vprintk(fmt, args);
  57         printk("\n");
  58         va_end(args);
  59
  60         if (test_opt(sb, ERRORS_PANIC))
  61                 panic("EXT2-fs panic from previous error\n");
  62         if (test_opt(sb, ERRORS_RO)) {
  63                 printk("Remounting filesystem read-only\n");
  64                 sb->s_flags |= MS_RDONLY;
  65         }
  66 }
  67
  68 void ext2_warning (struct super_block * sb, const char * function,
  69                    const char * fmt, ...)
  70 {
  71         va_list args;
  72
  73         va_start(args, fmt);
  74         printk(KERN_WARNING "EXT2-fs warning (device %s): %s: ",
  75                sb->s_id, function);
  76         vprintk(fmt, args);
  77         printk("\n");
  78         va_end(args);
  79 }
  80
  81 void ext2_update_dynamic_rev(struct super_block *sb)
  82 {
  83         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
  84
  85         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
  86                 return;
  87
  88         ext2_warning(sb, __FUNCTION__,
  89                      "updating to rev %d because of new feature flag, "
  90                      "running e2fsck is recommended",
  91                      EXT2_DYNAMIC_REV);
  92
  93         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
  94         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
  95         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
  96         /* leave es->s_feature_*compat flags alone */
  97         /* es->s_uuid will be set by e2fsck if empty */
  98
  99         /*
 100          * The rest of the superblock fields should be zero, and if not it
 101          * means they are likely already in use, so leave them alone.  We
 102          * can leave it up to e2fsck to clean up any inconsistencies there.
 103          */
 104 }
 105
 106 static void ext2_put_super (struct super_block * sb)
 107 {
 108         int db_count;
 109         int i;
 110         struct ext2_sb_info *sbi = EXT2_SB(sb);
 111
 112         ext2_xattr_put_super(sb);
 113         if (!(sb->s_flags & MS_RDONLY)) {
 114                 struct ext2_super_block *es = sbi->s_es;
 115
 116                 es->s_state = cpu_to_le16(sbi->s_mount_state);
 117                 ext2_sync_super(sb, es);
 118         }
 119         db_count = sbi->s_gdb_count;
 120         for (i = 0; i < db_count; i++)
 121                 if (sbi->s_group_desc[i])
 122                         brelse (sbi->s_group_desc[i]);
 123         kfree(sbi->s_group_desc);
 124         kfree(sbi->s_debts);
 125         percpu_counter_destroy(&sbi->s_freeblocks_counter);
 126         percpu_counter_destroy(&sbi->s_freeinodes_counter);
 127         percpu_counter_destroy(&sbi->s_dirs_counter);
 128         brelse (sbi->s_sbh);
 129         sb->s_fs_info = NULL;
 130         kfree(sbi);
 131
 132         return;
 133 }
 134
 135 static kmem_cache_t * ext2_inode_cachep;
 136
 137 static struct inode *ext2_alloc_inode(struct super_block *sb)
 138 {
 139         struct ext2_inode_info *ei;
 140         ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, SLAB_KERNEL);
 141         if (!ei)
 142                 return NULL;
 143 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 144         ei->i_acl = EXT2_ACL_NOT_CACHED;
 145         ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 146 #endif
 147         ei->vfs_inode.i_version = 1;
 148         return &ei->vfs_inode;
 149 }
 150
 151 static void ext2_destroy_inode(struct inode *inode)
 152 {
 153         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
 154 }
 155
 156 static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
 157 {
 158         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
 159
 160         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 161             SLAB_CTOR_CONSTRUCTOR) {
 162                 rwlock_init(&ei->i_meta_lock);
 163 #ifdef CONFIG_EXT2_FS_XATTR
 164                 init_rwsem(&ei->xattr_sem);
 165 #endif
 166                 inode_init_once(&ei->vfs_inode);
 167         }
 168 }
 169
 170 static int init_inodecache(void)
 171 {
 172         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
 173                                              sizeof(struct ext2_inode_info),
 174                                              0, SLAB_RECLAIM_ACCOUNT,
 175                                              init_once, NULL);
 176         if (ext2_inode_cachep == NULL)
 177                 return -ENOMEM;
 178         return 0;
 179 }
 180
 181 static void destroy_inodecache(void)
 182 {
 183         if (kmem_cache_destroy(ext2_inode_cachep))
 184                 printk(KERN_INFO "ext2_inode_cache: not all structures were freed\n");
 185 }
 186
 187 static void ext2_clear_inode(struct inode *inode)
 188 {
 189 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 190         struct ext2_inode_info *ei = EXT2_I(inode);
 191
 192         if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
 193                 posix_acl_release(ei->i_acl);
 194                 ei->i_acl = EXT2_ACL_NOT_CACHED;
 195         }
 196         if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
 197                 posix_acl_release(ei->i_default_acl);
 198                 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 199         }
 200 #endif
 201 }
 202
 203 #ifdef CONFIG_QUOTA
 204 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
 205 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
 206 #endif
 207
 208 static struct super_operations ext2_sops = {
 209         .alloc_inode    = ext2_alloc_inode,
 210         .destroy_inode  = ext2_destroy_inode,
 211         .read_inode     = ext2_read_inode,
 212         .write_inode    = ext2_write_inode,
 213         .put_inode      = ext2_put_inode,
 214         .delete_inode   = ext2_delete_inode,
 215         .put_super      = ext2_put_super,
 216         .write_super    = ext2_write_super,
 217         .statfs         = ext2_statfs,
 218         .remount_fs     = ext2_remount,
 219         .clear_inode    = ext2_clear_inode,
 220 #ifdef CONFIG_QUOTA
 221         .quota_read     = ext2_quota_read,
 222         .quota_write    = ext2_quota_write,
 223 #endif
 224 };
 225
 226 /* Yes, most of these are left as NULL!!
 227  * A NULL value implies the default, which works with ext2-like file
 228  * systems, but can be improved upon.
 229  * Currently only get_parent is required.
 230  */
 231 struct dentry *ext2_get_parent(struct dentry *child);
 232 static struct export_operations ext2_export_ops = {
 233         .get_parent = ext2_get_parent,
 234 };
 235
 236 static unsigned long get_sb_block(void **data)
 237 {
 238         unsigned long   sb_block;
 239         char            *options = (char *) *data;
 240
 241         if (!options || strncmp(options, "sb=", 3) != 0)
 242                 return 1;       /* Default location */
 243         options += 3;
 244         sb_block = simple_strtoul(options, &options, 0);
 245         if (*options && *options != ',') {
 246                 printk("EXT2-fs: Invalid sb specification: %s\n",
 247                        (char *) *data);
 248                 return 1;
 249         }
 250         if (*options == ',')
 251                 options++;
 252         *data = (void *) options;
 253         return sb_block;
 254 }
 255
 256 enum {
 257         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
 258         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
 259         Opt_nouid32, Opt_check, Opt_nocheck, Opt_debug, Opt_oldalloc, Opt_orlov, Opt_nobh,
 260         Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
 261         Opt_ignore, Opt_err,
 262 };
 263
 264 static match_table_t tokens = {
 265         {Opt_bsd_df, "bsddf"},
 266         {Opt_minix_df, "minixdf"},
 267         {Opt_grpid, "grpid"},
 268         {Opt_grpid, "bsdgroups"},
 269         {Opt_nogrpid, "nogrpid"},
 270         {Opt_nogrpid, "sysvgroups"},
 271         {Opt_resgid, "resgid=%u"},
 272         {Opt_resuid, "resuid=%u"},
 273         {Opt_sb, "sb=%u"},
 274         {Opt_err_cont, "errors=continue"},
 275         {Opt_err_panic, "errors=panic"},
 276         {Opt_err_ro, "errors=remount-ro"},
 277         {Opt_nouid32, "nouid32"},
 278         {Opt_nocheck, "check=none"},
 279         {Opt_nocheck, "nocheck"},
 280         {Opt_check, "check"},
 281         {Opt_debug, "debug"},
 282         {Opt_oldalloc, "oldalloc"},
 283         {Opt_orlov, "orlov"},
 284         {Opt_nobh, "nobh"},
 285         {Opt_user_xattr, "user_xattr"},
 286         {Opt_nouser_xattr, "nouser_xattr"},
 287         {Opt_acl, "acl"},
 288         {Opt_noacl, "noacl"},
 289         {Opt_ignore, "grpquota"},
 290         {Opt_ignore, "noquota"},
 291         {Opt_ignore, "quota"},
 292         {Opt_ignore, "usrquota"},
 293         {Opt_err, NULL}
 294 };
 295
 296 static int parse_options (char * options,
 297                           struct ext2_sb_info *sbi)
 298 {
 299         char * p;
 300         substring_t args[MAX_OPT_ARGS];
 301         unsigned long kind = EXT2_MOUNT_ERRORS_CONT;
 302         int option;
 303
 304         if (!options)
 305                 return 1;
 306
 307         while ((p = strsep (&options, ",")) != NULL) {
 308                 int token;
 309                 if (!*p)
 310                         continue;
 311
 312                 token = match_token(p, tokens, args);
 313                 switch (token) {
 314                 case Opt_bsd_df:
 315                         clear_opt (sbi->s_mount_opt, MINIX_DF);
 316                         break;
 317                 case Opt_minix_df:
 318                         set_opt (sbi->s_mount_opt, MINIX_DF);
 319                         break;
 320                 case Opt_grpid:
 321                         set_opt (sbi->s_mount_opt, GRPID);
 322                         break;
 323                 case Opt_nogrpid:
 324                         clear_opt (sbi->s_mount_opt, GRPID);
 325                         break;
 326                 case Opt_resuid:
 327                         if (match_int(&args[0], &option))
 328                                 return 0;
 329                         sbi->s_resuid = option;
 330                         break;
 331                 case Opt_resgid:
 332                         if (match_int(&args[0], &option))
 333                                 return 0;
 334                         sbi->s_resgid = option;
 335                         break;
 336                 case Opt_sb:
 337                         /* handled by get_sb_block() instead of here */
 338                         /* *sb_block = match_int(&args[0]); */
 339                         break;
 340                 case Opt_err_panic:
 341                         kind = EXT2_MOUNT_ERRORS_PANIC;
 342                         break;
 343                 case Opt_err_ro:
 344                         kind = EXT2_MOUNT_ERRORS_RO;
 345                         break;
 346                 case Opt_err_cont:
 347                         kind = EXT2_MOUNT_ERRORS_CONT;
 348                         break;
 349                 case Opt_nouid32:
 350                         set_opt (sbi->s_mount_opt, NO_UID32);
 351                         break;
 352                 case Opt_check:
 353 #ifdef CONFIG_EXT2_CHECK
 354                         set_opt (sbi->s_mount_opt, CHECK);
 355 #else
 356                         printk("EXT2 Check option not supported\n");
 357 #endif
 358                         break;
 359                 case Opt_nocheck:
 360                         clear_opt (sbi->s_mount_opt, CHECK);
 361                         break;
 362                 case Opt_debug:
 363                         set_opt (sbi->s_mount_opt, DEBUG);
 364                         break;
 365                 case Opt_oldalloc:
 366                         set_opt (sbi->s_mount_opt, OLDALLOC);
 367                         break;
 368                 case Opt_orlov:
 369                         clear_opt (sbi->s_mount_opt, OLDALLOC);
 370                         break;
 371                 case Opt_nobh:
 372                         set_opt (sbi->s_mount_opt, NOBH);
 373                         break;
 374 #ifdef CONFIG_EXT2_FS_XATTR
 375                 case Opt_user_xattr:
 376                         set_opt (sbi->s_mount_opt, XATTR_USER);
 377                         break;
 378                 case Opt_nouser_xattr:
 379                         clear_opt (sbi->s_mount_opt, XATTR_USER);
 380                         break;
 381 #else
 382                 case Opt_user_xattr:
 383                 case Opt_nouser_xattr:
 384                         printk("EXT2 (no)user_xattr options not supported\n");
 385                         break;
 386 #endif
 387 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 388                 case Opt_acl:
 389                         set_opt(sbi->s_mount_opt, POSIX_ACL);
 390                         break;
 391                 case Opt_noacl:
 392                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
 393                         break;
 394 #else
 395                 case Opt_acl:
 396                 case Opt_noacl:
 397                         printk("EXT2 (no)acl options not supported\n");
 398                         break;
 399 #endif
 400                 case Opt_ignore:
 401                         break;
 402                 default:
 403                         return 0;
 404                 }
 405         }
 406         sbi->s_mount_opt |= kind;
 407         return 1;
 408 }
 409
 410 static int ext2_setup_super (struct super_block * sb,
 411                               struct ext2_super_block * es,
 412                               int read_only)
 413 {
 414         int res = 0;
 415         struct ext2_sb_info *sbi = EXT2_SB(sb);
 416
 417         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 418                 printk ("EXT2-fs warning: revision level too high, "
 419                         "forcing read-only mode\n");
 420                 res = MS_RDONLY;
 421         }
 422         if (read_only)
 423                 return res;
 424         if (!(sbi->s_mount_state & EXT2_VALID_FS))
 425                 printk ("EXT2-fs warning: mounting unchecked fs, "
 426                         "running e2fsck is recommended\n");
 427         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 428                 printk ("EXT2-fs warning: mounting fs with errors, "
 429                         "running e2fsck is recommended\n");
 430         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 431                  le16_to_cpu(es->s_mnt_count) >=
 432                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 433                 printk ("EXT2-fs warning: maximal mount count reached, "
 434                         "running e2fsck is recommended\n");
 435         else if (le32_to_cpu(es->s_checkinterval) &&
 436                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 437                 printk ("EXT2-fs warning: checktime reached, "
 438                         "running e2fsck is recommended\n");
 439         if (!le16_to_cpu(es->s_max_mnt_count))
 440                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 441         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
 442         ext2_write_super(sb);
 443         if (test_opt (sb, DEBUG))
 444                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
 445                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
 446                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 447                         sbi->s_frag_size,
 448                         sbi->s_groups_count,
 449                         EXT2_BLOCKS_PER_GROUP(sb),
 450                         EXT2_INODES_PER_GROUP(sb),
 451                         sbi->s_mount_opt);
 452 #ifdef CONFIG_EXT2_CHECK
 453         if (test_opt (sb, CHECK)) {
 454                 ext2_check_blocks_bitmap (sb);
 455                 ext2_check_inodes_bitmap (sb);
 456         }
 457 #endif
 458         return res;
 459 }
 460
 461 static int ext2_check_descriptors (struct super_block * sb)
 462 {
 463         int i;
 464         int desc_block = 0;
 465         struct ext2_sb_info *sbi = EXT2_SB(sb);
 466         unsigned long block = le32_to_cpu(sbi->s_es->s_first_data_block);
 467         struct ext2_group_desc * gdp = NULL;
 468
 469         ext2_debug ("Checking group descriptors");
 470
 471         for (i = 0; i < sbi->s_groups_count; i++)
 472         {
 473                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
 474                         gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
 475                 if (le32_to_cpu(gdp->bg_block_bitmap) < block ||
 476                     le32_to_cpu(gdp->bg_block_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 477                 {
 478                         ext2_error (sb, "ext2_check_descriptors",
 479                                     "Block bitmap for group %d"
 480                                     " not in group (block %lu)!",
 481                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 482                         return 0;
 483                 }
 484                 if (le32_to_cpu(gdp->bg_inode_bitmap) < block ||
 485                     le32_to_cpu(gdp->bg_inode_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 486                 {
 487                         ext2_error (sb, "ext2_check_descriptors",
 488                                     "Inode bitmap for group %d"
 489                                     " not in group (block %lu)!",
 490                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 491                         return 0;
 492                 }
 493                 if (le32_to_cpu(gdp->bg_inode_table) < block ||
 494                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >=
 495                     block + EXT2_BLOCKS_PER_GROUP(sb))
 496                 {
 497                         ext2_error (sb, "ext2_check_descriptors",
 498                                     "Inode table for group %d"
 499                                     " not in group (block %lu)!",
 500                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 501                         return 0;
 502                 }
 503                 block += EXT2_BLOCKS_PER_GROUP(sb);
 504                 gdp++;
 505         }
 506         return 1;
 507 }
 508
 509 #define log2(n) ffz(~(n))
 510
 511 /*
 512  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 513  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 514  * We need to be 1 filesystem block less than the 2^32 sector limit.
 515  */
 516 static loff_t ext2_max_size(int bits)
 517 {
 518         loff_t res = EXT2_NDIR_BLOCKS;
 519         /* This constant is calculated to be the largest file size for a
 520          * dense, 4k-blocksize file such that the total number of
 521          * sectors in the file, including data and all indirect blocks,
 522          * does not exceed 2^32. */
 523         const loff_t upper_limit = 0x1ff7fffd000LL;
 524
 525         res += 1LL << (bits-2);
 526         res += 1LL << (2*(bits-2));
 527         res += 1LL << (3*(bits-2));
 528         res <<= bits;
 529         if (res > upper_limit)
 530                 res = upper_limit;
 531         return res;
 532 }
 533
 534 static unsigned long descriptor_loc(struct super_block *sb,
 535                                     unsigned long logic_sb_block,
 536                                     int nr)
 537 {
 538         struct ext2_sb_info *sbi = EXT2_SB(sb);
 539         unsigned long bg, first_data_block, first_meta_bg;
 540         int has_super = 0;
 541
 542         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 543         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 544
 545         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 546             nr < first_meta_bg)
 547                 return (logic_sb_block + nr + 1);
 548         bg = sbi->s_desc_per_block * nr;
 549         if (ext2_bg_has_super(sb, bg))
 550                 has_super = 1;
 551         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
 552 }
 553
 554 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 555 {
 556         struct buffer_head * bh;
 557         struct ext2_sb_info * sbi;
 558         struct ext2_super_block * es;
 559         struct inode *root;
 560         unsigned long block;
 561         unsigned long sb_block = get_sb_block(&data);
 562         unsigned long logic_sb_block;
 563         unsigned long offset = 0;
 564         unsigned long def_mount_opts;
 565         int blocksize = BLOCK_SIZE;
 566         int db_count;
 567         int i, j;
 568         __le32 features;
 569
 570         sbi = kmalloc(sizeof(*sbi), GFP_KERNEL);
 571         if (!sbi)
 572                 return -ENOMEM;
 573         sb->s_fs_info = sbi;
 574         memset(sbi, 0, sizeof(*sbi));
 575
 576         /*
 577          * See what the current blocksize for the device is, and
 578          * use that as the blocksize.  Otherwise (or if the blocksize
 579          * is smaller than the default) use the default.
 580          * This is important for devices that have a hardware
 581          * sectorsize that is larger than the default.
 582          */
 583         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 584         if (!blocksize) {
 585                 printk ("EXT2-fs: unable to set blocksize\n");
 586                 goto failed_sbi;
 587         }
 588
 589         /*
 590          * If the superblock doesn't start on a hardware sector boundary,
 591          * calculate the offset.
 592          */
 593         if (blocksize != BLOCK_SIZE) {
 594                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 595                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 596         } else {
 597                 logic_sb_block = sb_block;
 598         }
 599
 600         if (!(bh = sb_bread(sb, logic_sb_block))) {
 601                 printk ("EXT2-fs: unable to read superblock\n");
 602                 goto failed_sbi;
 603         }
 604         /*
 605          * Note: s_es must be initialized as soon as possible because
 606          *       some ext2 macro-instructions depend on its value
 607          */
 608         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 609         sbi->s_es = es;
 610         sb->s_magic = le16_to_cpu(es->s_magic);
 611
 612         if (sb->s_magic != EXT2_SUPER_MAGIC)
 613                 goto cantfind_ext2;
 614
 615         /* Set defaults before we parse the mount options */
 616         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 617         if (def_mount_opts & EXT2_DEFM_DEBUG)
 618                 set_opt(sbi->s_mount_opt, DEBUG);
 619         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 620                 set_opt(sbi->s_mount_opt, GRPID);
 621         if (def_mount_opts & EXT2_DEFM_UID16)
 622                 set_opt(sbi->s_mount_opt, NO_UID32);
 623         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 624                 set_opt(sbi->s_mount_opt, XATTR_USER);
 625         if (def_mount_opts & EXT2_DEFM_ACL)
 626                 set_opt(sbi->s_mount_opt, POSIX_ACL);
 627
 628         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 629                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 630         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
 631                 set_opt(sbi->s_mount_opt, ERRORS_RO);
 632
 633         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
 634         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
 635
 636         if (!parse_options ((char *) data, sbi))
 637                 goto failed_mount;
 638
 639         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 640                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 641                  MS_POSIXACL : 0);
 642
 643         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 644             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 645              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 646              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 647                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
 648                        "running e2fsck is recommended\n");
 649         /*
 650          * Check feature flags regardless of the revision level, since we
 651          * previously didn't change the revision level when setting the flags,
 652          * so there is a chance incompat flags are set on a rev 0 filesystem.
 653          */
 654         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 655         if (features) {
 656                 printk("EXT2-fs: %s: couldn't mount because of "
 657                        "unsupported optional features (%x).\n",
 658                        sb->s_id, le32_to_cpu(features));
 659                 goto failed_mount;
 660         }
 661         if (!(sb->s_flags & MS_RDONLY) &&
 662             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 663                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
 664                        "unsupported optional features (%x).\n",
 665                        sb->s_id, le32_to_cpu(features));
 666                 goto failed_mount;
 667         }
 668
 669         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 670
 671         /* If the blocksize doesn't match, re-read the thing.. */
 672         if (sb->s_blocksize != blocksize) {
 673                 brelse(bh);
 674
 675                 if (!sb_set_blocksize(sb, blocksize)) {
 676                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
 677                         goto failed_sbi;
 678                 }
 679
 680                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 681                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 682                 bh = sb_bread(sb, logic_sb_block);
 683                 if(!bh) {
 684                         printk("EXT2-fs: Couldn't read superblock on "
 685                                "2nd try.\n");
 686                         goto failed_sbi;
 687                 }
 688                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 689                 sbi->s_es = es;
 690                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 691                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
 692                         goto failed_mount;
 693                 }
 694         }
 695
 696         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 697
 698         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 699                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 700                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 701         } else {
 702                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 703                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 704                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 705                     (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
 706                     (sbi->s_inode_size > blocksize)) {
 707                         printk ("EXT2-fs: unsupported inode size: %d\n",
 708                                 sbi->s_inode_size);
 709                         goto failed_mount;
 710                 }
 711         }
 712
 713         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 714                                    le32_to_cpu(es->s_log_frag_size);
 715         if (sbi->s_frag_size == 0)
 716                 goto cantfind_ext2;
 717         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
 718
 719         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 720         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 721         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 722
 723         if (EXT2_INODE_SIZE(sb) == 0)
 724                 goto cantfind_ext2;
 725         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
 726         if (sbi->s_inodes_per_block == 0)
 727                 goto cantfind_ext2;
 728         sbi->s_itb_per_group = sbi->s_inodes_per_group /
 729                                         sbi->s_inodes_per_block;
 730         sbi->s_desc_per_block = sb->s_blocksize /
 731                                         sizeof (struct ext2_group_desc);
 732         sbi->s_sbh = bh;
 733         sbi->s_mount_state = le16_to_cpu(es->s_state);
 734         sbi->s_addr_per_block_bits =
 735                 log2 (EXT2_ADDR_PER_BLOCK(sb));
 736         sbi->s_desc_per_block_bits =
 737                 log2 (EXT2_DESC_PER_BLOCK(sb));
 738
 739         if (sb->s_magic != EXT2_SUPER_MAGIC)
 740                 goto cantfind_ext2;
 741
 742         if (sb->s_blocksize != bh->b_size) {
 743                 if (!silent)
 744                         printk ("VFS: Unsupported blocksize on dev "
 745                                 "%s.\n", sb->s_id);
 746                 goto failed_mount;
 747         }
 748
 749         if (sb->s_blocksize != sbi->s_frag_size) {
 750                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
 751                         sbi->s_frag_size, sb->s_blocksize);
 752                 goto failed_mount;
 753         }
 754
 755         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
 756                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
 757                         sbi->s_blocks_per_group);
 758                 goto failed_mount;
 759         }
 760         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 761                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
 762                         sbi->s_frags_per_group);
 763                 goto failed_mount;
 764         }
 765         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
 766                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
 767                         sbi->s_inodes_per_group);
 768                 goto failed_mount;
 769         }
 770
 771         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
 772                 goto cantfind_ext2;
 773         sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) -
 774                                         le32_to_cpu(es->s_first_data_block) +
 775                                        EXT2_BLOCKS_PER_GROUP(sb) - 1) /
 776                                        EXT2_BLOCKS_PER_GROUP(sb);
 777         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
 778                    EXT2_DESC_PER_BLOCK(sb);
 779         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
 780         if (sbi->s_group_desc == NULL) {
 781                 printk ("EXT2-fs: not enough memory\n");
 782                 goto failed_mount;
 783         }
 784         percpu_counter_init(&sbi->s_freeblocks_counter);
 785         percpu_counter_init(&sbi->s_freeinodes_counter);
 786         percpu_counter_init(&sbi->s_dirs_counter);
 787         bgl_lock_init(&sbi->s_blockgroup_lock);
 788         sbi->s_debts = kmalloc(sbi->s_groups_count * sizeof(*sbi->s_debts),
 789                                GFP_KERNEL);
 790         if (!sbi->s_debts) {
 791                 printk ("EXT2-fs: not enough memory\n");
 792                 goto failed_mount_group_desc;
 793         }
 794         memset(sbi->s_debts, 0, sbi->s_groups_count * sizeof(*sbi->s_debts));
 795         for (i = 0; i < db_count; i++) {
 796                 block = descriptor_loc(sb, logic_sb_block, i);
 797                 sbi->s_group_desc[i] = sb_bread(sb, block);
 798                 if (!sbi->s_group_desc[i]) {
 799                         for (j = 0; j < i; j++)
 800                                 brelse (sbi->s_group_desc[j]);
 801                         printk ("EXT2-fs: unable to read group descriptors\n");
 802                         goto failed_mount_group_desc;
 803                 }
 804         }
 805         if (!ext2_check_descriptors (sb)) {
 806                 printk ("EXT2-fs: group descriptors corrupted!\n");
 807                 db_count = i;
 808                 goto failed_mount2;
 809         }
 810         sbi->s_gdb_count = db_count;
 811         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
 812         spin_lock_init(&sbi->s_next_gen_lock);
 813         /*
 814          * set up enough so that it can read an inode
 815          */
 816         sb->s_op = &ext2_sops;
 817         sb->s_export_op = &ext2_export_ops;
 818         sb->s_xattr = ext2_xattr_handlers;
 819         root = iget(sb, EXT2_ROOT_INO);
 820         sb->s_root = d_alloc_root(root);
 821         if (!sb->s_root) {
 822                 iput(root);
 823                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
 824                 goto failed_mount2;
 825         }
 826         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
 827                 dput(sb->s_root);
 828                 sb->s_root = NULL;
 829                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
 830                 goto failed_mount2;
 831         }
 832         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 833                 ext2_warning(sb, __FUNCTION__,
 834                         "mounting ext3 filesystem as ext2\n");
 835         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
 836         percpu_counter_mod(&sbi->s_freeblocks_counter,
 837                                 ext2_count_free_blocks(sb));
 838         percpu_counter_mod(&sbi->s_freeinodes_counter,
 839                                 ext2_count_free_inodes(sb));
 840         percpu_counter_mod(&sbi->s_dirs_counter,
 841                                 ext2_count_dirs(sb));
 842         return 0;
 843
 844 cantfind_ext2:
 845         if (!silent)
 846                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
 847                        sb->s_id);
 848         goto failed_mount;
 849
 850 failed_mount2:
 851         for (i = 0; i < db_count; i++)
 852                 brelse(sbi->s_group_desc[i]);
 853 failed_mount_group_desc:
 854         kfree(sbi->s_group_desc);
 855         kfree(sbi->s_debts);
 856 failed_mount:
 857         brelse(bh);
 858 failed_sbi:
 859         sb->s_fs_info = NULL;
 860         kfree(sbi);
 861         return -EINVAL;
 862 }
 863
 864 static void ext2_commit_super (struct super_block * sb,
 865                                struct ext2_super_block * es)
 866 {
 867         es->s_wtime = cpu_to_le32(get_seconds());
 868         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 869         sb->s_dirt = 0;
 870 }
 871
 872 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
 873 {
 874         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 875         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 876         es->s_wtime = cpu_to_le32(get_seconds());
 877         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 878         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
 879         sb->s_dirt = 0;
 880 }
 881
 882 /*
 883  * In the second extended file system, it is not necessary to
 884  * write the super block since we use a mapping of the
 885  * disk super block in a buffer.
 886  *
 887  * However, this function is still used to set the fs valid
 888  * flags to 0.  We need to set this flag to 0 since the fs
 889  * may have been checked while mounted and e2fsck may have
 890  * set s_state to EXT2_VALID_FS after some corrections.
 891  */
 892
 893 void ext2_write_super (struct super_block * sb)
 894 {
 895         struct ext2_super_block * es;
 896         lock_kernel();
 897         if (!(sb->s_flags & MS_RDONLY)) {
 898                 es = EXT2_SB(sb)->s_es;
 899
 900                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
 901                         ext2_debug ("setting valid to 0\n");
 902                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
 903                                                   ~EXT2_VALID_FS);
 904                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 905                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 906                         es->s_mtime = cpu_to_le32(get_seconds());
 907                         ext2_sync_super(sb, es);
 908                 } else
 909                         ext2_commit_super (sb, es);
 910         }
 911         sb->s_dirt = 0;
 912         unlock_kernel();
 913 }
 914
 915 static int ext2_remount (struct super_block * sb, int * flags, char * data)
 916 {
 917         struct ext2_sb_info * sbi = EXT2_SB(sb);
 918         struct ext2_super_block * es;
 919
 920         /*
 921          * Allow the "check" option to be passed as a remount option.
 922          */
 923         if (!parse_options (data, sbi))
 924                 return -EINVAL;
 925
 926         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 927                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
 928
 929         es = sbi->s_es;
 930         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 931                 return 0;
 932         if (*flags & MS_RDONLY) {
 933                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
 934                     !(sbi->s_mount_state & EXT2_VALID_FS))
 935                         return 0;
 936                 /*
 937                  * OK, we are remounting a valid rw partition rdonly, so set
 938                  * the rdonly flag and then mark the partition as valid again.
 939                  */
 940                 es->s_state = cpu_to_le16(sbi->s_mount_state);
 941                 es->s_mtime = cpu_to_le32(get_seconds());
 942         } else {
 943                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
 944                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
 945                 if (ret) {
 946                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
 947                                "unsupported optional features (%x).\n",
 948                                sb->s_id, le32_to_cpu(ret));
 949                         return -EROFS;
 950                 }
 951                 /*
 952                  * Mounting a RDONLY partition read-write, so reread and
 953                  * store the current valid flag.  (It may have been changed
 954                  * by e2fsck since we originally mounted the partition.)
 955                  */
 956                 sbi->s_mount_state = le16_to_cpu(es->s_state);
 957                 if (!ext2_setup_super (sb, es, 0))
 958                         sb->s_flags &= ~MS_RDONLY;
 959         }
 960         ext2_sync_super(sb, es);
 961         return 0;
 962 }
 963
 964 static int ext2_statfs (struct super_block * sb, struct kstatfs * buf)
 965 {
 966         struct ext2_sb_info *sbi = EXT2_SB(sb);
 967         unsigned long overhead;
 968         int i;
 969
 970         if (test_opt (sb, MINIX_DF))
 971                 overhead = 0;
 972         else {
 973                 /*
 974                  * Compute the overhead (FS structures)
 975                  */
 976
 977                 /*
 978                  * All of the blocks before first_data_block are
 979                  * overhead
 980                  */
 981                 overhead = le32_to_cpu(sbi->s_es->s_first_data_block);
 982
 983                 /*
 984                  * Add the overhead attributed to the superblock and
 985                  * block group descriptors.  If the sparse superblocks
 986                  * feature is turned on, then not all groups have this.
 987                  */
 988                 for (i = 0; i < sbi->s_groups_count; i++)
 989                         overhead += ext2_bg_has_super(sb, i) +
 990                                 ext2_bg_num_gdb(sb, i);
 991
 992                 /*
 993                  * Every block group has an inode bitmap, a block
 994                  * bitmap, and an inode table.
 995                  */
 996                 overhead += (sbi->s_groups_count *
 997                              (2 + sbi->s_itb_per_group));
 998         }
 999
1000         buf->f_type = EXT2_SUPER_MAGIC;
1001         buf->f_bsize = sb->s_blocksize;
1002         buf->f_blocks = le32_to_cpu(sbi->s_es->s_blocks_count) - overhead;
1003         buf->f_bfree = ext2_count_free_blocks(sb);
1004         buf->f_bavail = buf->f_bfree - le32_to_cpu(sbi->s_es->s_r_blocks_count);
1005         if (buf->f_bfree < le32_to_cpu(sbi->s_es->s_r_blocks_count))
1006                 buf->f_bavail = 0;
1007         buf->f_files = le32_to_cpu(sbi->s_es->s_inodes_count);
1008         buf->f_ffree = ext2_count_free_inodes (sb);
1009         buf->f_namelen = EXT2_NAME_LEN;
1010         return 0;
1011 }
1012
1013 static struct super_block *ext2_get_sb(struct file_system_type *fs_type,
1014         int flags, const char *dev_name, void *data)
1015 {
1016         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1017 }
1018
1019 #ifdef CONFIG_QUOTA
1020
1021 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1022  * acquiring the locks... As quota files are never truncated and quota code
1023  * itself serializes the operations (and noone else should touch the files)
1024  * we don't have to be afraid of races */
1025 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1026                                size_t len, loff_t off)
1027 {
1028         struct inode *inode = sb_dqopt(sb)->files[type];
1029         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1030         int err = 0;
1031         int offset = off & (sb->s_blocksize - 1);
1032         int tocopy;
1033         size_t toread;
1034         struct buffer_head tmp_bh;
1035         struct buffer_head *bh;
1036         loff_t i_size = i_size_read(inode);
1037
1038         if (off > i_size)
1039                 return 0;
1040         if (off+len > i_size)
1041                 len = i_size-off;
1042         toread = len;
1043         while (toread > 0) {
1044                 tocopy = sb->s_blocksize - offset < toread ?
1045                                 sb->s_blocksize - offset : toread;
1046
1047                 tmp_bh.b_state = 0;
1048                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1049                 if (err)
1050                         return err;
1051                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1052                         memset(data, 0, tocopy);
1053                 else {
1054                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1055                         if (!bh)
1056                                 return -EIO;
1057                         memcpy(data, bh->b_data+offset, tocopy);
1058                         brelse(bh);
1059                 }
1060                 offset = 0;
1061                 toread -= tocopy;
1062                 data += tocopy;
1063                 blk++;
1064         }
1065         return len;
1066 }
1067
1068 /* Write to quotafile */
1069 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1070                                 const char *data, size_t len, loff_t off)
1071 {
1072         struct inode *inode = sb_dqopt(sb)->files[type];
1073         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1074         int err = 0;
1075         int offset = off & (sb->s_blocksize - 1);
1076         int tocopy;
1077         size_t towrite = len;
1078         struct buffer_head tmp_bh;
1079         struct buffer_head *bh;
1080
1081         down(&inode->i_sem);
1082         while (towrite > 0) {
1083                 tocopy = sb->s_blocksize - offset < towrite ?
1084                                 sb->s_blocksize - offset : towrite;
1085
1086                 tmp_bh.b_state = 0;
1087                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1088                 if (err)
1089                         goto out;
1090                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1091                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1092                 else
1093                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1094                 if (!bh) {
1095                         err = -EIO;
1096                         goto out;
1097                 }
1098                 lock_buffer(bh);
1099                 memcpy(bh->b_data+offset, data, tocopy);
1100                 flush_dcache_page(bh->b_page);
1101                 set_buffer_uptodate(bh);
1102                 mark_buffer_dirty(bh);
1103                 unlock_buffer(bh);
1104                 brelse(bh);
1105                 offset = 0;
1106                 towrite -= tocopy;
1107                 data += tocopy;
1108                 blk++;
1109         }
1110 out:
1111         if (len == towrite)
1112                 return err;
1113         if (inode->i_size < off+len-towrite)
1114                 i_size_write(inode, off+len-towrite);
1115         inode->i_version++;
1116         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1117         mark_inode_dirty(inode);
1118         up(&inode->i_sem);
1119         return len - towrite;
1120 }
1121
1122 #endif
1123
1124 static struct file_system_type ext2_fs_type = {
1125         .owner          = THIS_MODULE,
1126         .name           = "ext2",
1127         .get_sb         = ext2_get_sb,
1128         .kill_sb        = kill_block_super,
1129         .fs_flags       = FS_REQUIRES_DEV,
1130 };
1131
1132 static int __init init_ext2_fs(void)
1133 {
1134         int err = init_ext2_xattr();
1135         if (err)
1136                 return err;
1137         err = init_inodecache();
1138         if (err)
1139                 goto out1;
1140         err = register_filesystem(&ext2_fs_type);
1141         if (err)
1142                 goto out;
1143         return 0;
1144 out:
1145         destroy_inodecache();
1146 out1:
1147         exit_ext2_xattr();
1148         return err;
1149 }
1150
1151 static void __exit exit_ext2_fs(void)
1152 {
1153         unregister_filesystem(&ext2_fs_type);
1154         destroy_inodecache();
1155         exit_ext2_xattr();
1156 }
1157
1158 module_init(init_ext2_fs)
1159 module_exit(exit_ext2_fs)