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         if (!is_bad_inode(inode))
 202                 ext2_discard_prealloc(inode);
 203 }
 204
 205
 206 #ifdef CONFIG_QUOTA
 207 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
 208 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
 209 #endif
 210
 211 static struct super_operations ext2_sops = {
 212         .alloc_inode    = ext2_alloc_inode,
 213         .destroy_inode  = ext2_destroy_inode,
 214         .read_inode     = ext2_read_inode,
 215         .write_inode    = ext2_write_inode,
 216         .delete_inode   = ext2_delete_inode,
 217         .put_super      = ext2_put_super,
 218         .write_super    = ext2_write_super,
 219         .statfs         = ext2_statfs,
 220         .remount_fs     = ext2_remount,
 221         .clear_inode    = ext2_clear_inode,
 222 #ifdef CONFIG_QUOTA
 223         .quota_read     = ext2_quota_read,
 224         .quota_write    = ext2_quota_write,
 225 #endif
 226 };
 227
 228 /* Yes, most of these are left as NULL!!
 229  * A NULL value implies the default, which works with ext2-like file
 230  * systems, but can be improved upon.
 231  * Currently only get_parent is required.
 232  */
 233 struct dentry *ext2_get_parent(struct dentry *child);
 234 static struct export_operations ext2_export_ops = {
 235         .get_parent = ext2_get_parent,
 236 };
 237
 238 static unsigned long get_sb_block(void **data)
 239 {
 240         unsigned long   sb_block;
 241         char            *options = (char *) *data;
 242
 243         if (!options || strncmp(options, "sb=", 3) != 0)
 244                 return 1;       /* Default location */
 245         options += 3;
 246         sb_block = simple_strtoul(options, &options, 0);
 247         if (*options && *options != ',') {
 248                 printk("EXT2-fs: Invalid sb specification: %s\n",
 249                        (char *) *data);
 250                 return 1;
 251         }
 252         if (*options == ',')
 253                 options++;
 254         *data = (void *) options;
 255         return sb_block;
 256 }
 257
 258 enum {
 259         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
 260         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
 261         Opt_nouid32, Opt_check, Opt_nocheck, Opt_debug, Opt_oldalloc, Opt_orlov, Opt_nobh,
 262         Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl, Opt_tagxid,
 263         Opt_ignore, Opt_err,
 264 };
 265
 266 static match_table_t tokens = {
 267         {Opt_bsd_df, "bsddf"},
 268         {Opt_minix_df, "minixdf"},
 269         {Opt_grpid, "grpid"},
 270         {Opt_grpid, "bsdgroups"},
 271         {Opt_nogrpid, "nogrpid"},
 272         {Opt_nogrpid, "sysvgroups"},
 273         {Opt_resgid, "resgid=%u"},
 274         {Opt_resuid, "resuid=%u"},
 275         {Opt_sb, "sb=%u"},
 276         {Opt_err_cont, "errors=continue"},
 277         {Opt_err_panic, "errors=panic"},
 278         {Opt_err_ro, "errors=remount-ro"},
 279         {Opt_nouid32, "nouid32"},
 280         {Opt_nocheck, "check=none"},
 281         {Opt_nocheck, "nocheck"},
 282         {Opt_check, "check"},
 283         {Opt_debug, "debug"},
 284         {Opt_oldalloc, "oldalloc"},
 285         {Opt_orlov, "orlov"},
 286         {Opt_nobh, "nobh"},
 287         {Opt_user_xattr, "user_xattr"},
 288         {Opt_nouser_xattr, "nouser_xattr"},
 289         {Opt_acl, "acl"},
 290         {Opt_noacl, "noacl"},
 291         {Opt_tagxid, "tagxid"},
 292         {Opt_ignore, "grpquota"},
 293         {Opt_ignore, "noquota"},
 294         {Opt_ignore, "quota"},
 295         {Opt_ignore, "usrquota"},
 296         {Opt_err, NULL}
 297 };
 298
 299 static int parse_options (char * options,
 300                           struct ext2_sb_info *sbi)
 301 {
 302         char * p;
 303         substring_t args[MAX_OPT_ARGS];
 304         unsigned long kind = EXT2_MOUNT_ERRORS_CONT;
 305         int option;
 306
 307         if (!options)
 308                 return 1;
 309
 310         while ((p = strsep (&options, ",")) != NULL) {
 311                 int token;
 312                 if (!*p)
 313                         continue;
 314
 315                 token = match_token(p, tokens, args);
 316                 switch (token) {
 317                 case Opt_bsd_df:
 318                         clear_opt (sbi->s_mount_opt, MINIX_DF);
 319                         break;
 320                 case Opt_minix_df:
 321                         set_opt (sbi->s_mount_opt, MINIX_DF);
 322                         break;
 323                 case Opt_grpid:
 324                         set_opt (sbi->s_mount_opt, GRPID);
 325                         break;
 326                 case Opt_nogrpid:
 327                         clear_opt (sbi->s_mount_opt, GRPID);
 328                         break;
 329                 case Opt_resuid:
 330                         if (match_int(&args[0], &option))
 331                                 return 0;
 332                         sbi->s_resuid = option;
 333                         break;
 334                 case Opt_resgid:
 335                         if (match_int(&args[0], &option))
 336                                 return 0;
 337                         sbi->s_resgid = option;
 338                         break;
 339                 case Opt_sb:
 340                         /* handled by get_sb_block() instead of here */
 341                         /* *sb_block = match_int(&args[0]); */
 342                         break;
 343                 case Opt_err_panic:
 344                         kind = EXT2_MOUNT_ERRORS_PANIC;
 345                         break;
 346                 case Opt_err_ro:
 347                         kind = EXT2_MOUNT_ERRORS_RO;
 348                         break;
 349                 case Opt_err_cont:
 350                         kind = EXT2_MOUNT_ERRORS_CONT;
 351                         break;
 352                 case Opt_nouid32:
 353                         set_opt (sbi->s_mount_opt, NO_UID32);
 354                         break;
 355 #ifndef CONFIG_INOXID_NONE
 356                 case Opt_tagxid:
 357                         set_opt (sbi->s_mount_opt, TAG_XID);
 358                         break;
 359 #endif
 360                 case Opt_check:
 361 #ifdef CONFIG_EXT2_CHECK
 362                         set_opt (sbi->s_mount_opt, CHECK);
 363 #else
 364                         printk("EXT2 Check option not supported\n");
 365 #endif
 366                         break;
 367                 case Opt_nocheck:
 368                         clear_opt (sbi->s_mount_opt, CHECK);
 369                         break;
 370                 case Opt_debug:
 371                         set_opt (sbi->s_mount_opt, DEBUG);
 372                         break;
 373                 case Opt_oldalloc:
 374                         set_opt (sbi->s_mount_opt, OLDALLOC);
 375                         break;
 376                 case Opt_orlov:
 377                         clear_opt (sbi->s_mount_opt, OLDALLOC);
 378                         break;
 379                 case Opt_nobh:
 380                         set_opt (sbi->s_mount_opt, NOBH);
 381                         break;
 382 #ifdef CONFIG_EXT2_FS_XATTR
 383                 case Opt_user_xattr:
 384                         set_opt (sbi->s_mount_opt, XATTR_USER);
 385                         break;
 386                 case Opt_nouser_xattr:
 387                         clear_opt (sbi->s_mount_opt, XATTR_USER);
 388                         break;
 389 #else
 390                 case Opt_user_xattr:
 391                 case Opt_nouser_xattr:
 392                         printk("EXT2 (no)user_xattr options not supported\n");
 393                         break;
 394 #endif
 395 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 396                 case Opt_acl:
 397                         set_opt(sbi->s_mount_opt, POSIX_ACL);
 398                         break;
 399                 case Opt_noacl:
 400                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
 401                         break;
 402 #else
 403                 case Opt_acl:
 404                 case Opt_noacl:
 405                         printk("EXT2 (no)acl options not supported\n");
 406                         break;
 407 #endif
 408                 case Opt_ignore:
 409                         break;
 410                 default:
 411                         return 0;
 412                 }
 413         }
 414         sbi->s_mount_opt |= kind;
 415         return 1;
 416 }
 417
 418 static int ext2_setup_super (struct super_block * sb,
 419                               struct ext2_super_block * es,
 420                               int read_only)
 421 {
 422         int res = 0;
 423         struct ext2_sb_info *sbi = EXT2_SB(sb);
 424
 425         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 426                 printk ("EXT2-fs warning: revision level too high, "
 427                         "forcing read-only mode\n");
 428                 res = MS_RDONLY;
 429         }
 430         if (read_only)
 431                 return res;
 432         if (!(sbi->s_mount_state & EXT2_VALID_FS))
 433                 printk ("EXT2-fs warning: mounting unchecked fs, "
 434                         "running e2fsck is recommended\n");
 435         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 436                 printk ("EXT2-fs warning: mounting fs with errors, "
 437                         "running e2fsck is recommended\n");
 438         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 439                  le16_to_cpu(es->s_mnt_count) >=
 440                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 441                 printk ("EXT2-fs warning: maximal mount count reached, "
 442                         "running e2fsck is recommended\n");
 443         else if (le32_to_cpu(es->s_checkinterval) &&
 444                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 445                 printk ("EXT2-fs warning: checktime reached, "
 446                         "running e2fsck is recommended\n");
 447         if (!le16_to_cpu(es->s_max_mnt_count))
 448                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 449         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
 450         ext2_write_super(sb);
 451         if (test_opt (sb, DEBUG))
 452                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
 453                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
 454                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 455                         sbi->s_frag_size,
 456                         sbi->s_groups_count,
 457                         EXT2_BLOCKS_PER_GROUP(sb),
 458                         EXT2_INODES_PER_GROUP(sb),
 459                         sbi->s_mount_opt);
 460 #ifdef CONFIG_EXT2_CHECK
 461         if (test_opt (sb, CHECK)) {
 462                 ext2_check_blocks_bitmap (sb);
 463                 ext2_check_inodes_bitmap (sb);
 464         }
 465 #endif
 466         return res;
 467 }
 468
 469 static int ext2_check_descriptors (struct super_block * sb)
 470 {
 471         int i;
 472         int desc_block = 0;
 473         struct ext2_sb_info *sbi = EXT2_SB(sb);
 474         unsigned long block = le32_to_cpu(sbi->s_es->s_first_data_block);
 475         struct ext2_group_desc * gdp = NULL;
 476
 477         ext2_debug ("Checking group descriptors");
 478
 479         for (i = 0; i < sbi->s_groups_count; i++)
 480         {
 481                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
 482                         gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
 483                 if (le32_to_cpu(gdp->bg_block_bitmap) < block ||
 484                     le32_to_cpu(gdp->bg_block_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 485                 {
 486                         ext2_error (sb, "ext2_check_descriptors",
 487                                     "Block bitmap for group %d"
 488                                     " not in group (block %lu)!",
 489                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 490                         return 0;
 491                 }
 492                 if (le32_to_cpu(gdp->bg_inode_bitmap) < block ||
 493                     le32_to_cpu(gdp->bg_inode_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 494                 {
 495                         ext2_error (sb, "ext2_check_descriptors",
 496                                     "Inode bitmap for group %d"
 497                                     " not in group (block %lu)!",
 498                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 499                         return 0;
 500                 }
 501                 if (le32_to_cpu(gdp->bg_inode_table) < block ||
 502                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >=
 503                     block + EXT2_BLOCKS_PER_GROUP(sb))
 504                 {
 505                         ext2_error (sb, "ext2_check_descriptors",
 506                                     "Inode table for group %d"
 507                                     " not in group (block %lu)!",
 508                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 509                         return 0;
 510                 }
 511                 block += EXT2_BLOCKS_PER_GROUP(sb);
 512                 gdp++;
 513         }
 514         return 1;
 515 }
 516
 517 #define log2(n) ffz(~(n))
 518
 519 /*
 520  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 521  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 522  * We need to be 1 filesystem block less than the 2^32 sector limit.
 523  */
 524 static loff_t ext2_max_size(int bits)
 525 {
 526         loff_t res = EXT2_NDIR_BLOCKS;
 527         res += 1LL << (bits-2);
 528         res += 1LL << (2*(bits-2));
 529         res += 1LL << (3*(bits-2));
 530         res <<= bits;
 531         if (res > (512LL << 32) - (1 << bits))
 532                 res = (512LL << 32) - (1 << bits);
 533         return res;
 534 }
 535
 536 static unsigned long descriptor_loc(struct super_block *sb,
 537                                     unsigned long logic_sb_block,
 538                                     int nr)
 539 {
 540         struct ext2_sb_info *sbi = EXT2_SB(sb);
 541         unsigned long bg, first_data_block, first_meta_bg;
 542         int has_super = 0;
 543
 544         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 545         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 546
 547         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 548             nr < first_meta_bg)
 549                 return (logic_sb_block + nr + 1);
 550         bg = sbi->s_desc_per_block * nr;
 551         if (ext2_bg_has_super(sb, bg))
 552                 has_super = 1;
 553         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
 554 }
 555
 556 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 557 {
 558         struct buffer_head * bh;
 559         struct ext2_sb_info * sbi;
 560         struct ext2_super_block * es;
 561         struct inode *root;
 562         unsigned long block;
 563         unsigned long sb_block = get_sb_block(&data);
 564         unsigned long logic_sb_block;
 565         unsigned long offset = 0;
 566         unsigned long def_mount_opts;
 567         int blocksize = BLOCK_SIZE;
 568         int db_count;
 569         int i, j;
 570         __le32 features;
 571
 572         sbi = kmalloc(sizeof(*sbi), GFP_KERNEL);
 573         if (!sbi)
 574                 return -ENOMEM;
 575         sb->s_fs_info = sbi;
 576         memset(sbi, 0, sizeof(*sbi));
 577
 578         /*
 579          * See what the current blocksize for the device is, and
 580          * use that as the blocksize.  Otherwise (or if the blocksize
 581          * is smaller than the default) use the default.
 582          * This is important for devices that have a hardware
 583          * sectorsize that is larger than the default.
 584          */
 585         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 586         if (!blocksize) {
 587                 printk ("EXT2-fs: unable to set blocksize\n");
 588                 goto failed_sbi;
 589         }
 590
 591         /*
 592          * If the superblock doesn't start on a hardware sector boundary,
 593          * calculate the offset.
 594          */
 595         if (blocksize != BLOCK_SIZE) {
 596                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 597                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 598         } else {
 599                 logic_sb_block = sb_block;
 600         }
 601
 602         if (!(bh = sb_bread(sb, logic_sb_block))) {
 603                 printk ("EXT2-fs: unable to read superblock\n");
 604                 goto failed_sbi;
 605         }
 606         /*
 607          * Note: s_es must be initialized as soon as possible because
 608          *       some ext2 macro-instructions depend on its value
 609          */
 610         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 611         sbi->s_es = es;
 612         sb->s_magic = le16_to_cpu(es->s_magic);
 613
 614         if (sb->s_magic != EXT2_SUPER_MAGIC)
 615                 goto cantfind_ext2;
 616
 617         /* Set defaults before we parse the mount options */
 618         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 619         if (def_mount_opts & EXT2_DEFM_DEBUG)
 620                 set_opt(sbi->s_mount_opt, DEBUG);
 621         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 622                 set_opt(sbi->s_mount_opt, GRPID);
 623         if (def_mount_opts & EXT2_DEFM_UID16)
 624                 set_opt(sbi->s_mount_opt, NO_UID32);
 625         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 626                 set_opt(sbi->s_mount_opt, XATTR_USER);
 627         if (def_mount_opts & EXT2_DEFM_ACL)
 628                 set_opt(sbi->s_mount_opt, POSIX_ACL);
 629
 630         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 631                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 632         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
 633                 set_opt(sbi->s_mount_opt, ERRORS_RO);
 634
 635         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
 636         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
 637
 638         if (!parse_options ((char *) data, sbi))
 639                 goto failed_mount;
 640
 641         if (EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_TAG_XID)
 642                 sb->s_flags |= MS_TAGXID;
 643         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 644                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 645                  MS_POSIXACL : 0);
 646
 647         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 648             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 649              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 650              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 651                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
 652                        "running e2fsck is recommended\n");
 653         /*
 654          * Check feature flags regardless of the revision level, since we
 655          * previously didn't change the revision level when setting the flags,
 656          * so there is a chance incompat flags are set on a rev 0 filesystem.
 657          */
 658         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 659         if (features) {
 660                 printk("EXT2-fs: %s: couldn't mount because of "
 661                        "unsupported optional features (%x).\n",
 662                        sb->s_id, le32_to_cpu(features));
 663                 goto failed_mount;
 664         }
 665         if (!(sb->s_flags & MS_RDONLY) &&
 666             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 667                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
 668                        "unsupported optional features (%x).\n",
 669                        sb->s_id, le32_to_cpu(features));
 670                 goto failed_mount;
 671         }
 672
 673         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 674
 675         /* If the blocksize doesn't match, re-read the thing.. */
 676         if (sb->s_blocksize != blocksize) {
 677                 brelse(bh);
 678
 679                 if (!sb_set_blocksize(sb, blocksize)) {
 680                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
 681                         goto failed_sbi;
 682                 }
 683
 684                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 685                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 686                 bh = sb_bread(sb, logic_sb_block);
 687                 if(!bh) {
 688                         printk("EXT2-fs: Couldn't read superblock on "
 689                                "2nd try.\n");
 690                         goto failed_sbi;
 691                 }
 692                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 693                 sbi->s_es = es;
 694                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 695                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
 696                         goto failed_mount;
 697                 }
 698         }
 699
 700         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 701
 702         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 703                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 704                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 705         } else {
 706                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 707                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 708                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 709                     (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
 710                     (sbi->s_inode_size > blocksize)) {
 711                         printk ("EXT2-fs: unsupported inode size: %d\n",
 712                                 sbi->s_inode_size);
 713                         goto failed_mount;
 714                 }
 715         }
 716
 717         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 718                                    le32_to_cpu(es->s_log_frag_size);
 719         if (sbi->s_frag_size == 0)
 720                 goto cantfind_ext2;
 721         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
 722
 723         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 724         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 725         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 726
 727         if (EXT2_INODE_SIZE(sb) == 0)
 728                 goto cantfind_ext2;
 729         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
 730         if (sbi->s_inodes_per_block == 0)
 731                 goto cantfind_ext2;
 732         sbi->s_itb_per_group = sbi->s_inodes_per_group /
 733                                         sbi->s_inodes_per_block;
 734         sbi->s_desc_per_block = sb->s_blocksize /
 735                                         sizeof (struct ext2_group_desc);
 736         sbi->s_sbh = bh;
 737         sbi->s_mount_state = le16_to_cpu(es->s_state);
 738         sbi->s_addr_per_block_bits =
 739                 log2 (EXT2_ADDR_PER_BLOCK(sb));
 740         sbi->s_desc_per_block_bits =
 741                 log2 (EXT2_DESC_PER_BLOCK(sb));
 742
 743         if (sb->s_magic != EXT2_SUPER_MAGIC)
 744                 goto cantfind_ext2;
 745
 746         if (sb->s_blocksize != bh->b_size) {
 747                 if (!silent)
 748                         printk ("VFS: Unsupported blocksize on dev "
 749                                 "%s.\n", sb->s_id);
 750                 goto failed_mount;
 751         }
 752
 753         if (sb->s_blocksize != sbi->s_frag_size) {
 754                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
 755                         sbi->s_frag_size, sb->s_blocksize);
 756                 goto failed_mount;
 757         }
 758
 759         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
 760                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
 761                         sbi->s_blocks_per_group);
 762                 goto failed_mount;
 763         }
 764         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 765                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
 766                         sbi->s_frags_per_group);
 767                 goto failed_mount;
 768         }
 769         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
 770                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
 771                         sbi->s_inodes_per_group);
 772                 goto failed_mount;
 773         }
 774
 775         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
 776                 goto cantfind_ext2;
 777         sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) -
 778                                         le32_to_cpu(es->s_first_data_block) +
 779                                        EXT2_BLOCKS_PER_GROUP(sb) - 1) /
 780                                        EXT2_BLOCKS_PER_GROUP(sb);
 781         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
 782                    EXT2_DESC_PER_BLOCK(sb);
 783         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
 784         if (sbi->s_group_desc == NULL) {
 785                 printk ("EXT2-fs: not enough memory\n");
 786                 goto failed_mount;
 787         }
 788         percpu_counter_init(&sbi->s_freeblocks_counter);
 789         percpu_counter_init(&sbi->s_freeinodes_counter);
 790         percpu_counter_init(&sbi->s_dirs_counter);
 791         bgl_lock_init(&sbi->s_blockgroup_lock);
 792         sbi->s_debts = kmalloc(sbi->s_groups_count * sizeof(*sbi->s_debts),
 793                                GFP_KERNEL);
 794         if (!sbi->s_debts) {
 795                 printk ("EXT2-fs: not enough memory\n");
 796                 goto failed_mount_group_desc;
 797         }
 798         memset(sbi->s_debts, 0, sbi->s_groups_count * sizeof(*sbi->s_debts));
 799         for (i = 0; i < db_count; i++) {
 800                 block = descriptor_loc(sb, logic_sb_block, i);
 801                 sbi->s_group_desc[i] = sb_bread(sb, block);
 802                 if (!sbi->s_group_desc[i]) {
 803                         for (j = 0; j < i; j++)
 804                                 brelse (sbi->s_group_desc[j]);
 805                         printk ("EXT2-fs: unable to read group descriptors\n");
 806                         goto failed_mount_group_desc;
 807                 }
 808         }
 809         if (!ext2_check_descriptors (sb)) {
 810                 printk ("EXT2-fs: group descriptors corrupted!\n");
 811                 db_count = i;
 812                 goto failed_mount2;
 813         }
 814         sbi->s_gdb_count = db_count;
 815         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
 816         spin_lock_init(&sbi->s_next_gen_lock);
 817         /*
 818          * set up enough so that it can read an inode
 819          */
 820         sb->s_op = &ext2_sops;
 821         sb->s_export_op = &ext2_export_ops;
 822         sb->s_xattr = ext2_xattr_handlers;
 823         root = iget(sb, EXT2_ROOT_INO);
 824         sb->s_root = d_alloc_root(root);
 825         if (!sb->s_root) {
 826                 iput(root);
 827                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
 828                 goto failed_mount2;
 829         }
 830         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
 831                 dput(sb->s_root);
 832                 sb->s_root = NULL;
 833                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
 834                 goto failed_mount2;
 835         }
 836         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 837                 ext2_warning(sb, __FUNCTION__,
 838                         "mounting ext3 filesystem as ext2\n");
 839         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
 840         percpu_counter_mod(&sbi->s_freeblocks_counter,
 841                                 ext2_count_free_blocks(sb));
 842         percpu_counter_mod(&sbi->s_freeinodes_counter,
 843                                 ext2_count_free_inodes(sb));
 844         percpu_counter_mod(&sbi->s_dirs_counter,
 845                                 ext2_count_dirs(sb));
 846         return 0;
 847
 848 cantfind_ext2:
 849         if (!silent)
 850                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
 851                        sb->s_id);
 852         goto failed_mount;
 853
 854 failed_mount2:
 855         for (i = 0; i < db_count; i++)
 856                 brelse(sbi->s_group_desc[i]);
 857 failed_mount_group_desc:
 858         kfree(sbi->s_group_desc);
 859         kfree(sbi->s_debts);
 860 failed_mount:
 861         brelse(bh);
 862 failed_sbi:
 863         sb->s_fs_info = NULL;
 864         kfree(sbi);
 865         return -EINVAL;
 866 }
 867
 868 static void ext2_commit_super (struct super_block * sb,
 869                                struct ext2_super_block * es)
 870 {
 871         es->s_wtime = cpu_to_le32(get_seconds());
 872         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 873         sb->s_dirt = 0;
 874 }
 875
 876 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
 877 {
 878         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 879         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 880         es->s_wtime = cpu_to_le32(get_seconds());
 881         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 882         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
 883         sb->s_dirt = 0;
 884 }
 885
 886 /*
 887  * In the second extended file system, it is not necessary to
 888  * write the super block since we use a mapping of the
 889  * disk super block in a buffer.
 890  *
 891  * However, this function is still used to set the fs valid
 892  * flags to 0.  We need to set this flag to 0 since the fs
 893  * may have been checked while mounted and e2fsck may have
 894  * set s_state to EXT2_VALID_FS after some corrections.
 895  */
 896
 897 void ext2_write_super (struct super_block * sb)
 898 {
 899         struct ext2_super_block * es;
 900         lock_kernel();
 901         if (!(sb->s_flags & MS_RDONLY)) {
 902                 es = EXT2_SB(sb)->s_es;
 903
 904                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
 905                         ext2_debug ("setting valid to 0\n");
 906                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
 907                                                   ~EXT2_VALID_FS);
 908                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 909                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 910                         es->s_mtime = cpu_to_le32(get_seconds());
 911                         ext2_sync_super(sb, es);
 912                 } else
 913                         ext2_commit_super (sb, es);
 914         }
 915         sb->s_dirt = 0;
 916         unlock_kernel();
 917 }
 918
 919 static int ext2_remount (struct super_block * sb, int * flags, char * data)
 920 {
 921         struct ext2_sb_info * sbi = EXT2_SB(sb);
 922         struct ext2_super_block * es;
 923
 924         /*
 925          * Allow the "check" option to be passed as a remount option.
 926          */
 927         if (!parse_options (data, sbi))
 928                 return -EINVAL;
 929
 930         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 931                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
 932
 933         es = sbi->s_es;
 934         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 935                 return 0;
 936         if (*flags & MS_RDONLY) {
 937                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
 938                     !(sbi->s_mount_state & EXT2_VALID_FS))
 939                         return 0;
 940                 /*
 941                  * OK, we are remounting a valid rw partition rdonly, so set
 942                  * the rdonly flag and then mark the partition as valid again.
 943                  */
 944                 es->s_state = cpu_to_le16(sbi->s_mount_state);
 945                 es->s_mtime = cpu_to_le32(get_seconds());
 946         } else {
 947                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
 948                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
 949                 if (ret) {
 950                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
 951                                "unsupported optional features (%x).\n",
 952                                sb->s_id, le32_to_cpu(ret));
 953                         return -EROFS;
 954                 }
 955                 /*
 956                  * Mounting a RDONLY partition read-write, so reread and
 957                  * store the current valid flag.  (It may have been changed
 958                  * by e2fsck since we originally mounted the partition.)
 959                  */
 960                 sbi->s_mount_state = le16_to_cpu(es->s_state);
 961                 if (!ext2_setup_super (sb, es, 0))
 962                         sb->s_flags &= ~MS_RDONLY;
 963         }
 964         ext2_sync_super(sb, es);
 965         return 0;
 966 }
 967
 968 static int ext2_statfs (struct super_block * sb, struct kstatfs * buf)
 969 {
 970         struct ext2_sb_info *sbi = EXT2_SB(sb);
 971         unsigned long overhead;
 972         int i;
 973
 974         if (test_opt (sb, MINIX_DF))
 975                 overhead = 0;
 976         else {
 977                 /*
 978                  * Compute the overhead (FS structures)
 979                  */
 980
 981                 /*
 982                  * All of the blocks before first_data_block are
 983                  * overhead
 984                  */
 985                 overhead = le32_to_cpu(sbi->s_es->s_first_data_block);
 986
 987                 /*
 988                  * Add the overhead attributed to the superblock and
 989                  * block group descriptors.  If the sparse superblocks
 990                  * feature is turned on, then not all groups have this.
 991                  */
 992                 for (i = 0; i < sbi->s_groups_count; i++)
 993                         overhead += ext2_bg_has_super(sb, i) +
 994                                 ext2_bg_num_gdb(sb, i);
 995
 996                 /*
 997                  * Every block group has an inode bitmap, a block
 998                  * bitmap, and an inode table.
 999                  */
1000                 overhead += (sbi->s_groups_count *
1001                              (2 + sbi->s_itb_per_group));
1002         }
1003
1004         buf->f_type = EXT2_SUPER_MAGIC;
1005         buf->f_bsize = sb->s_blocksize;
1006         buf->f_blocks = le32_to_cpu(sbi->s_es->s_blocks_count) - overhead;
1007         buf->f_bfree = ext2_count_free_blocks(sb);
1008         buf->f_bavail = buf->f_bfree - le32_to_cpu(sbi->s_es->s_r_blocks_count);
1009         if (buf->f_bfree < le32_to_cpu(sbi->s_es->s_r_blocks_count))
1010                 buf->f_bavail = 0;
1011         buf->f_files = le32_to_cpu(sbi->s_es->s_inodes_count);
1012         buf->f_ffree = ext2_count_free_inodes (sb);
1013         buf->f_namelen = EXT2_NAME_LEN;
1014         return 0;
1015 }
1016
1017 static struct super_block *ext2_get_sb(struct file_system_type *fs_type,
1018         int flags, const char *dev_name, void *data)
1019 {
1020         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1021 }
1022
1023 #ifdef CONFIG_QUOTA
1024
1025 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1026  * acquiring the locks... As quota files are never truncated and quota code
1027  * itself serializes the operations (and noone else should touch the files)
1028  * we don't have to be afraid of races */
1029 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1030                                size_t len, loff_t off)
1031 {
1032         struct inode *inode = sb_dqopt(sb)->files[type];
1033         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1034         int err = 0;
1035         int offset = off & (sb->s_blocksize - 1);
1036         int tocopy;
1037         size_t toread;
1038         struct buffer_head tmp_bh;
1039         struct buffer_head *bh;
1040         loff_t i_size = i_size_read(inode);
1041
1042         if (off > i_size)
1043                 return 0;
1044         if (off+len > i_size)
1045                 len = i_size-off;
1046         toread = len;
1047         while (toread > 0) {
1048                 tocopy = sb->s_blocksize - offset < toread ?
1049                                 sb->s_blocksize - offset : toread;
1050
1051                 tmp_bh.b_state = 0;
1052                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1053                 if (err)
1054                         return err;
1055                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1056                         memset(data, 0, tocopy);
1057                 else {
1058                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1059                         if (!bh)
1060                                 return -EIO;
1061                         memcpy(data, bh->b_data+offset, tocopy);
1062                         brelse(bh);
1063                 }
1064                 offset = 0;
1065                 toread -= tocopy;
1066                 data += tocopy;
1067                 blk++;
1068         }
1069         return len;
1070 }
1071
1072 /* Write to quotafile */
1073 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1074                                 const char *data, size_t len, loff_t off)
1075 {
1076         struct inode *inode = sb_dqopt(sb)->files[type];
1077         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1078         int err = 0;
1079         int offset = off & (sb->s_blocksize - 1);
1080         int tocopy;
1081         size_t towrite = len;
1082         struct buffer_head tmp_bh;
1083         struct buffer_head *bh;
1084
1085         down(&inode->i_sem);
1086         while (towrite > 0) {
1087                 tocopy = sb->s_blocksize - offset < towrite ?
1088                                 sb->s_blocksize - offset : towrite;
1089
1090                 tmp_bh.b_state = 0;
1091                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1092                 if (err)
1093                         goto out;
1094                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1095                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1096                 else
1097                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1098                 if (!bh) {
1099                         err = -EIO;
1100                         goto out;
1101                 }
1102                 lock_buffer(bh);
1103                 memcpy(bh->b_data+offset, data, tocopy);
1104                 flush_dcache_page(bh->b_page);
1105                 set_buffer_uptodate(bh);
1106                 mark_buffer_dirty(bh);
1107                 unlock_buffer(bh);
1108                 brelse(bh);
1109                 offset = 0;
1110                 towrite -= tocopy;
1111                 data += tocopy;
1112                 blk++;
1113         }
1114 out:
1115         if (len == towrite)
1116                 return err;
1117         if (inode->i_size < off+len-towrite)
1118                 i_size_write(inode, off+len-towrite);
1119         inode->i_version++;
1120         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1121         mark_inode_dirty(inode);
1122         up(&inode->i_sem);
1123         return len - towrite;
1124 }
1125
1126 #endif
1127
1128 static struct file_system_type ext2_fs_type = {
1129         .owner          = THIS_MODULE,
1130         .name           = "ext2",
1131         .get_sb         = ext2_get_sb,
1132         .kill_sb        = kill_block_super,
1133         .fs_flags       = FS_REQUIRES_DEV,
1134 };
1135
1136 static int __init init_ext2_fs(void)
1137 {
1138         int err = init_ext2_xattr();
1139         if (err)
1140                 return err;
1141         err = init_inodecache();
1142         if (err)
1143                 goto out1;
1144         err = register_filesystem(&ext2_fs_type);
1145         if (err)
1146                 goto out;
1147         return 0;
1148 out:
1149         destroy_inodecache();
1150 out1:
1151         exit_ext2_xattr();
1152         return err;
1153 }
1154
1155 static void __exit exit_ext2_fs(void)
1156 {
1157         unregister_filesystem(&ext2_fs_type);
1158         destroy_inodecache();
1159         exit_ext2_xattr();
1160 }
1161
1162 module_init(init_ext2_fs)
1163 module_exit(exit_ext2_fs)