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, Opt_tagxid,
 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_tagxid, "tagxid"},
 290         {Opt_ignore, "grpquota"},
 291         {Opt_ignore, "noquota"},
 292         {Opt_ignore, "quota"},
 293         {Opt_ignore, "usrquota"},
 294         {Opt_err, NULL}
 295 };
 296
 297 static int parse_options (char * options,
 298                           struct ext2_sb_info *sbi)
 299 {
 300         char * p;
 301         substring_t args[MAX_OPT_ARGS];
 302         unsigned long kind = EXT2_MOUNT_ERRORS_CONT;
 303         int option;
 304
 305         if (!options)
 306                 return 1;
 307
 308         while ((p = strsep (&options, ",")) != NULL) {
 309                 int token;
 310                 if (!*p)
 311                         continue;
 312
 313                 token = match_token(p, tokens, args);
 314                 switch (token) {
 315                 case Opt_bsd_df:
 316                         clear_opt (sbi->s_mount_opt, MINIX_DF);
 317                         break;
 318                 case Opt_minix_df:
 319                         set_opt (sbi->s_mount_opt, MINIX_DF);
 320                         break;
 321                 case Opt_grpid:
 322                         set_opt (sbi->s_mount_opt, GRPID);
 323                         break;
 324                 case Opt_nogrpid:
 325                         clear_opt (sbi->s_mount_opt, GRPID);
 326                         break;
 327                 case Opt_resuid:
 328                         if (match_int(&args[0], &option))
 329                                 return 0;
 330                         sbi->s_resuid = option;
 331                         break;
 332                 case Opt_resgid:
 333                         if (match_int(&args[0], &option))
 334                                 return 0;
 335                         sbi->s_resgid = option;
 336                         break;
 337                 case Opt_sb:
 338                         /* handled by get_sb_block() instead of here */
 339                         /* *sb_block = match_int(&args[0]); */
 340                         break;
 341                 case Opt_err_panic:
 342                         kind = EXT2_MOUNT_ERRORS_PANIC;
 343                         break;
 344                 case Opt_err_ro:
 345                         kind = EXT2_MOUNT_ERRORS_RO;
 346                         break;
 347                 case Opt_err_cont:
 348                         kind = EXT2_MOUNT_ERRORS_CONT;
 349                         break;
 350                 case Opt_nouid32:
 351                         set_opt (sbi->s_mount_opt, NO_UID32);
 352                         break;
 353 #ifndef CONFIG_INOXID_NONE
 354                 case Opt_tagxid:
 355                         set_opt (sbi->s_mount_opt, TAG_XID);
 356                         break;
 357 #endif
 358                 case Opt_check:
 359 #ifdef CONFIG_EXT2_CHECK
 360                         set_opt (sbi->s_mount_opt, CHECK);
 361 #else
 362                         printk("EXT2 Check option not supported\n");
 363 #endif
 364                         break;
 365                 case Opt_nocheck:
 366                         clear_opt (sbi->s_mount_opt, CHECK);
 367                         break;
 368                 case Opt_debug:
 369                         set_opt (sbi->s_mount_opt, DEBUG);
 370                         break;
 371                 case Opt_oldalloc:
 372                         set_opt (sbi->s_mount_opt, OLDALLOC);
 373                         break;
 374                 case Opt_orlov:
 375                         clear_opt (sbi->s_mount_opt, OLDALLOC);
 376                         break;
 377                 case Opt_nobh:
 378                         set_opt (sbi->s_mount_opt, NOBH);
 379                         break;
 380 #ifdef CONFIG_EXT2_FS_XATTR
 381                 case Opt_user_xattr:
 382                         set_opt (sbi->s_mount_opt, XATTR_USER);
 383                         break;
 384                 case Opt_nouser_xattr:
 385                         clear_opt (sbi->s_mount_opt, XATTR_USER);
 386                         break;
 387 #else
 388                 case Opt_user_xattr:
 389                 case Opt_nouser_xattr:
 390                         printk("EXT2 (no)user_xattr options not supported\n");
 391                         break;
 392 #endif
 393 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 394                 case Opt_acl:
 395                         set_opt(sbi->s_mount_opt, POSIX_ACL);
 396                         break;
 397                 case Opt_noacl:
 398                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
 399                         break;
 400 #else
 401                 case Opt_acl:
 402                 case Opt_noacl:
 403                         printk("EXT2 (no)acl options not supported\n");
 404                         break;
 405 #endif
 406                 case Opt_ignore:
 407                         break;
 408                 default:
 409                         return 0;
 410                 }
 411         }
 412         sbi->s_mount_opt |= kind;
 413         return 1;
 414 }
 415
 416 static int ext2_setup_super (struct super_block * sb,
 417                               struct ext2_super_block * es,
 418                               int read_only)
 419 {
 420         int res = 0;
 421         struct ext2_sb_info *sbi = EXT2_SB(sb);
 422
 423         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 424                 printk ("EXT2-fs warning: revision level too high, "
 425                         "forcing read-only mode\n");
 426                 res = MS_RDONLY;
 427         }
 428         if (read_only)
 429                 return res;
 430         if (!(sbi->s_mount_state & EXT2_VALID_FS))
 431                 printk ("EXT2-fs warning: mounting unchecked fs, "
 432                         "running e2fsck is recommended\n");
 433         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 434                 printk ("EXT2-fs warning: mounting fs with errors, "
 435                         "running e2fsck is recommended\n");
 436         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 437                  le16_to_cpu(es->s_mnt_count) >=
 438                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 439                 printk ("EXT2-fs warning: maximal mount count reached, "
 440                         "running e2fsck is recommended\n");
 441         else if (le32_to_cpu(es->s_checkinterval) &&
 442                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 443                 printk ("EXT2-fs warning: checktime reached, "
 444                         "running e2fsck is recommended\n");
 445         if (!le16_to_cpu(es->s_max_mnt_count))
 446                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 447         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
 448         ext2_write_super(sb);
 449         if (test_opt (sb, DEBUG))
 450                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
 451                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
 452                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 453                         sbi->s_frag_size,
 454                         sbi->s_groups_count,
 455                         EXT2_BLOCKS_PER_GROUP(sb),
 456                         EXT2_INODES_PER_GROUP(sb),
 457                         sbi->s_mount_opt);
 458 #ifdef CONFIG_EXT2_CHECK
 459         if (test_opt (sb, CHECK)) {
 460                 ext2_check_blocks_bitmap (sb);
 461                 ext2_check_inodes_bitmap (sb);
 462         }
 463 #endif
 464         return res;
 465 }
 466
 467 static int ext2_check_descriptors (struct super_block * sb)
 468 {
 469         int i;
 470         int desc_block = 0;
 471         struct ext2_sb_info *sbi = EXT2_SB(sb);
 472         unsigned long block = le32_to_cpu(sbi->s_es->s_first_data_block);
 473         struct ext2_group_desc * gdp = NULL;
 474
 475         ext2_debug ("Checking group descriptors");
 476
 477         for (i = 0; i < sbi->s_groups_count; i++)
 478         {
 479                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
 480                         gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
 481                 if (le32_to_cpu(gdp->bg_block_bitmap) < block ||
 482                     le32_to_cpu(gdp->bg_block_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 483                 {
 484                         ext2_error (sb, "ext2_check_descriptors",
 485                                     "Block bitmap for group %d"
 486                                     " not in group (block %lu)!",
 487                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 488                         return 0;
 489                 }
 490                 if (le32_to_cpu(gdp->bg_inode_bitmap) < block ||
 491                     le32_to_cpu(gdp->bg_inode_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 492                 {
 493                         ext2_error (sb, "ext2_check_descriptors",
 494                                     "Inode bitmap for group %d"
 495                                     " not in group (block %lu)!",
 496                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 497                         return 0;
 498                 }
 499                 if (le32_to_cpu(gdp->bg_inode_table) < block ||
 500                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >=
 501                     block + EXT2_BLOCKS_PER_GROUP(sb))
 502                 {
 503                         ext2_error (sb, "ext2_check_descriptors",
 504                                     "Inode table for group %d"
 505                                     " not in group (block %lu)!",
 506                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 507                         return 0;
 508                 }
 509                 block += EXT2_BLOCKS_PER_GROUP(sb);
 510                 gdp++;
 511         }
 512         return 1;
 513 }
 514
 515 #define log2(n) ffz(~(n))
 516
 517 /*
 518  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 519  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 520  * We need to be 1 filesystem block less than the 2^32 sector limit.
 521  */
 522 static loff_t ext2_max_size(int bits)
 523 {
 524         loff_t res = EXT2_NDIR_BLOCKS;
 525         /* This constant is calculated to be the largest file size for a
 526          * dense, 4k-blocksize file such that the total number of
 527          * sectors in the file, including data and all indirect blocks,
 528          * does not exceed 2^32. */
 529         const loff_t upper_limit = 0x1ff7fffd000LL;
 530
 531         res += 1LL << (bits-2);
 532         res += 1LL << (2*(bits-2));
 533         res += 1LL << (3*(bits-2));
 534         res <<= bits;
 535         if (res > upper_limit)
 536                 res = upper_limit;
 537         return res;
 538 }
 539
 540 static unsigned long descriptor_loc(struct super_block *sb,
 541                                     unsigned long logic_sb_block,
 542                                     int nr)
 543 {
 544         struct ext2_sb_info *sbi = EXT2_SB(sb);
 545         unsigned long bg, first_data_block, first_meta_bg;
 546         int has_super = 0;
 547
 548         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 549         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 550
 551         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 552             nr < first_meta_bg)
 553                 return (logic_sb_block + nr + 1);
 554         bg = sbi->s_desc_per_block * nr;
 555         if (ext2_bg_has_super(sb, bg))
 556                 has_super = 1;
 557         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
 558 }
 559
 560 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 561 {
 562         struct buffer_head * bh;
 563         struct ext2_sb_info * sbi;
 564         struct ext2_super_block * es;
 565         struct inode *root;
 566         unsigned long block;
 567         unsigned long sb_block = get_sb_block(&data);
 568         unsigned long logic_sb_block;
 569         unsigned long offset = 0;
 570         unsigned long def_mount_opts;
 571         int blocksize = BLOCK_SIZE;
 572         int db_count;
 573         int i, j;
 574         __le32 features;
 575
 576         sbi = kmalloc(sizeof(*sbi), GFP_KERNEL);
 577         if (!sbi)
 578                 return -ENOMEM;
 579         sb->s_fs_info = sbi;
 580         memset(sbi, 0, sizeof(*sbi));
 581
 582         /*
 583          * See what the current blocksize for the device is, and
 584          * use that as the blocksize.  Otherwise (or if the blocksize
 585          * is smaller than the default) use the default.
 586          * This is important for devices that have a hardware
 587          * sectorsize that is larger than the default.
 588          */
 589         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 590         if (!blocksize) {
 591                 printk ("EXT2-fs: unable to set blocksize\n");
 592                 goto failed_sbi;
 593         }
 594
 595         /*
 596          * If the superblock doesn't start on a hardware sector boundary,
 597          * calculate the offset.
 598          */
 599         if (blocksize != BLOCK_SIZE) {
 600                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 601                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 602         } else {
 603                 logic_sb_block = sb_block;
 604         }
 605
 606         if (!(bh = sb_bread(sb, logic_sb_block))) {
 607                 printk ("EXT2-fs: unable to read superblock\n");
 608                 goto failed_sbi;
 609         }
 610         /*
 611          * Note: s_es must be initialized as soon as possible because
 612          *       some ext2 macro-instructions depend on its value
 613          */
 614         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 615         sbi->s_es = es;
 616         sb->s_magic = le16_to_cpu(es->s_magic);
 617
 618         if (sb->s_magic != EXT2_SUPER_MAGIC)
 619                 goto cantfind_ext2;
 620
 621         /* Set defaults before we parse the mount options */
 622         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 623         if (def_mount_opts & EXT2_DEFM_DEBUG)
 624                 set_opt(sbi->s_mount_opt, DEBUG);
 625         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 626                 set_opt(sbi->s_mount_opt, GRPID);
 627         if (def_mount_opts & EXT2_DEFM_UID16)
 628                 set_opt(sbi->s_mount_opt, NO_UID32);
 629         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 630                 set_opt(sbi->s_mount_opt, XATTR_USER);
 631         if (def_mount_opts & EXT2_DEFM_ACL)
 632                 set_opt(sbi->s_mount_opt, POSIX_ACL);
 633
 634         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 635                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 636         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
 637                 set_opt(sbi->s_mount_opt, ERRORS_RO);
 638
 639         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
 640         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
 641
 642         if (!parse_options ((char *) data, sbi))
 643                 goto failed_mount;
 644
 645         if (EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_TAG_XID)
 646                 sb->s_flags |= MS_TAGXID;
 647         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 648                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 649                  MS_POSIXACL : 0);
 650
 651         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 652             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 653              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 654              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 655                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
 656                        "running e2fsck is recommended\n");
 657         /*
 658          * Check feature flags regardless of the revision level, since we
 659          * previously didn't change the revision level when setting the flags,
 660          * so there is a chance incompat flags are set on a rev 0 filesystem.
 661          */
 662         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 663         if (features) {
 664                 printk("EXT2-fs: %s: couldn't mount because of "
 665                        "unsupported optional features (%x).\n",
 666                        sb->s_id, le32_to_cpu(features));
 667                 goto failed_mount;
 668         }
 669         if (!(sb->s_flags & MS_RDONLY) &&
 670             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 671                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
 672                        "unsupported optional features (%x).\n",
 673                        sb->s_id, le32_to_cpu(features));
 674                 goto failed_mount;
 675         }
 676
 677         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 678
 679         /* If the blocksize doesn't match, re-read the thing.. */
 680         if (sb->s_blocksize != blocksize) {
 681                 brelse(bh);
 682
 683                 if (!sb_set_blocksize(sb, blocksize)) {
 684                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
 685                         goto failed_sbi;
 686                 }
 687
 688                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 689                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 690                 bh = sb_bread(sb, logic_sb_block);
 691                 if(!bh) {
 692                         printk("EXT2-fs: Couldn't read superblock on "
 693                                "2nd try.\n");
 694                         goto failed_sbi;
 695                 }
 696                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 697                 sbi->s_es = es;
 698                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 699                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
 700                         goto failed_mount;
 701                 }
 702         }
 703
 704         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 705
 706         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 707                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 708                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 709         } else {
 710                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 711                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 712                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 713                     (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
 714                     (sbi->s_inode_size > blocksize)) {
 715                         printk ("EXT2-fs: unsupported inode size: %d\n",
 716                                 sbi->s_inode_size);
 717                         goto failed_mount;
 718                 }
 719         }
 720
 721         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 722                                    le32_to_cpu(es->s_log_frag_size);
 723         if (sbi->s_frag_size == 0)
 724                 goto cantfind_ext2;
 725         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
 726
 727         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 728         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 729         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 730
 731         if (EXT2_INODE_SIZE(sb) == 0)
 732                 goto cantfind_ext2;
 733         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
 734         if (sbi->s_inodes_per_block == 0)
 735                 goto cantfind_ext2;
 736         sbi->s_itb_per_group = sbi->s_inodes_per_group /
 737                                         sbi->s_inodes_per_block;
 738         sbi->s_desc_per_block = sb->s_blocksize /
 739                                         sizeof (struct ext2_group_desc);
 740         sbi->s_sbh = bh;
 741         sbi->s_mount_state = le16_to_cpu(es->s_state);
 742         sbi->s_addr_per_block_bits =
 743                 log2 (EXT2_ADDR_PER_BLOCK(sb));
 744         sbi->s_desc_per_block_bits =
 745                 log2 (EXT2_DESC_PER_BLOCK(sb));
 746
 747         if (sb->s_magic != EXT2_SUPER_MAGIC)
 748                 goto cantfind_ext2;
 749
 750         if (sb->s_blocksize != bh->b_size) {
 751                 if (!silent)
 752                         printk ("VFS: Unsupported blocksize on dev "
 753                                 "%s.\n", sb->s_id);
 754                 goto failed_mount;
 755         }
 756
 757         if (sb->s_blocksize != sbi->s_frag_size) {
 758                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
 759                         sbi->s_frag_size, sb->s_blocksize);
 760                 goto failed_mount;
 761         }
 762
 763         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
 764                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
 765                         sbi->s_blocks_per_group);
 766                 goto failed_mount;
 767         }
 768         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 769                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
 770                         sbi->s_frags_per_group);
 771                 goto failed_mount;
 772         }
 773         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
 774                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
 775                         sbi->s_inodes_per_group);
 776                 goto failed_mount;
 777         }
 778
 779         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
 780                 goto cantfind_ext2;
 781         sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) -
 782                                         le32_to_cpu(es->s_first_data_block) +
 783                                        EXT2_BLOCKS_PER_GROUP(sb) - 1) /
 784                                        EXT2_BLOCKS_PER_GROUP(sb);
 785         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
 786                    EXT2_DESC_PER_BLOCK(sb);
 787         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
 788         if (sbi->s_group_desc == NULL) {
 789                 printk ("EXT2-fs: not enough memory\n");
 790                 goto failed_mount;
 791         }
 792         percpu_counter_init(&sbi->s_freeblocks_counter);
 793         percpu_counter_init(&sbi->s_freeinodes_counter);
 794         percpu_counter_init(&sbi->s_dirs_counter);
 795         bgl_lock_init(&sbi->s_blockgroup_lock);
 796         sbi->s_debts = kmalloc(sbi->s_groups_count * sizeof(*sbi->s_debts),
 797                                GFP_KERNEL);
 798         if (!sbi->s_debts) {
 799                 printk ("EXT2-fs: not enough memory\n");
 800                 goto failed_mount_group_desc;
 801         }
 802         memset(sbi->s_debts, 0, sbi->s_groups_count * sizeof(*sbi->s_debts));
 803         for (i = 0; i < db_count; i++) {
 804                 block = descriptor_loc(sb, logic_sb_block, i);
 805                 sbi->s_group_desc[i] = sb_bread(sb, block);
 806                 if (!sbi->s_group_desc[i]) {
 807                         for (j = 0; j < i; j++)
 808                                 brelse (sbi->s_group_desc[j]);
 809                         printk ("EXT2-fs: unable to read group descriptors\n");
 810                         goto failed_mount_group_desc;
 811                 }
 812         }
 813         if (!ext2_check_descriptors (sb)) {
 814                 printk ("EXT2-fs: group descriptors corrupted!\n");
 815                 db_count = i;
 816                 goto failed_mount2;
 817         }
 818         sbi->s_gdb_count = db_count;
 819         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
 820         spin_lock_init(&sbi->s_next_gen_lock);
 821         /*
 822          * set up enough so that it can read an inode
 823          */
 824         sb->s_op = &ext2_sops;
 825         sb->s_export_op = &ext2_export_ops;
 826         sb->s_xattr = ext2_xattr_handlers;
 827         root = iget(sb, EXT2_ROOT_INO);
 828         sb->s_root = d_alloc_root(root);
 829         if (!sb->s_root) {
 830                 iput(root);
 831                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
 832                 goto failed_mount2;
 833         }
 834         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
 835                 dput(sb->s_root);
 836                 sb->s_root = NULL;
 837                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
 838                 goto failed_mount2;
 839         }
 840         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 841                 ext2_warning(sb, __FUNCTION__,
 842                         "mounting ext3 filesystem as ext2\n");
 843         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
 844         percpu_counter_mod(&sbi->s_freeblocks_counter,
 845                                 ext2_count_free_blocks(sb));
 846         percpu_counter_mod(&sbi->s_freeinodes_counter,
 847                                 ext2_count_free_inodes(sb));
 848         percpu_counter_mod(&sbi->s_dirs_counter,
 849                                 ext2_count_dirs(sb));
 850         return 0;
 851
 852 cantfind_ext2:
 853         if (!silent)
 854                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
 855                        sb->s_id);
 856         goto failed_mount;
 857
 858 failed_mount2:
 859         for (i = 0; i < db_count; i++)
 860                 brelse(sbi->s_group_desc[i]);
 861 failed_mount_group_desc:
 862         kfree(sbi->s_group_desc);
 863         kfree(sbi->s_debts);
 864 failed_mount:
 865         brelse(bh);
 866 failed_sbi:
 867         sb->s_fs_info = NULL;
 868         kfree(sbi);
 869         return -EINVAL;
 870 }
 871
 872 static void ext2_commit_super (struct super_block * sb,
 873                                struct ext2_super_block * es)
 874 {
 875         es->s_wtime = cpu_to_le32(get_seconds());
 876         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 877         sb->s_dirt = 0;
 878 }
 879
 880 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
 881 {
 882         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 883         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 884         es->s_wtime = cpu_to_le32(get_seconds());
 885         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 886         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
 887         sb->s_dirt = 0;
 888 }
 889
 890 /*
 891  * In the second extended file system, it is not necessary to
 892  * write the super block since we use a mapping of the
 893  * disk super block in a buffer.
 894  *
 895  * However, this function is still used to set the fs valid
 896  * flags to 0.  We need to set this flag to 0 since the fs
 897  * may have been checked while mounted and e2fsck may have
 898  * set s_state to EXT2_VALID_FS after some corrections.
 899  */
 900
 901 void ext2_write_super (struct super_block * sb)
 902 {
 903         struct ext2_super_block * es;
 904         lock_kernel();
 905         if (!(sb->s_flags & MS_RDONLY)) {
 906                 es = EXT2_SB(sb)->s_es;
 907
 908                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
 909                         ext2_debug ("setting valid to 0\n");
 910                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
 911                                                   ~EXT2_VALID_FS);
 912                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 913                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 914                         es->s_mtime = cpu_to_le32(get_seconds());
 915                         ext2_sync_super(sb, es);
 916                 } else
 917                         ext2_commit_super (sb, es);
 918         }
 919         sb->s_dirt = 0;
 920         unlock_kernel();
 921 }
 922
 923 static int ext2_remount (struct super_block * sb, int * flags, char * data)
 924 {
 925         struct ext2_sb_info * sbi = EXT2_SB(sb);
 926         struct ext2_super_block * es;
 927
 928         /*
 929          * Allow the "check" option to be passed as a remount option.
 930          */
 931         if (!parse_options (data, sbi))
 932                 return -EINVAL;
 933
 934         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 935                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
 936
 937         es = sbi->s_es;
 938         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 939                 return 0;
 940         if (*flags & MS_RDONLY) {
 941                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
 942                     !(sbi->s_mount_state & EXT2_VALID_FS))
 943                         return 0;
 944                 /*
 945                  * OK, we are remounting a valid rw partition rdonly, so set
 946                  * the rdonly flag and then mark the partition as valid again.
 947                  */
 948                 es->s_state = cpu_to_le16(sbi->s_mount_state);
 949                 es->s_mtime = cpu_to_le32(get_seconds());
 950         } else {
 951                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
 952                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
 953                 if (ret) {
 954                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
 955                                "unsupported optional features (%x).\n",
 956                                sb->s_id, le32_to_cpu(ret));
 957                         return -EROFS;
 958                 }
 959                 /*
 960                  * Mounting a RDONLY partition read-write, so reread and
 961                  * store the current valid flag.  (It may have been changed
 962                  * by e2fsck since we originally mounted the partition.)
 963                  */
 964                 sbi->s_mount_state = le16_to_cpu(es->s_state);
 965                 if (!ext2_setup_super (sb, es, 0))
 966                         sb->s_flags &= ~MS_RDONLY;
 967         }
 968         ext2_sync_super(sb, es);
 969         return 0;
 970 }
 971
 972 static int ext2_statfs (struct super_block * sb, struct kstatfs * buf)
 973 {
 974         struct ext2_sb_info *sbi = EXT2_SB(sb);
 975         unsigned long overhead;
 976         int i;
 977
 978         if (test_opt (sb, MINIX_DF))
 979                 overhead = 0;
 980         else {
 981                 /*
 982                  * Compute the overhead (FS structures)
 983                  */
 984
 985                 /*
 986                  * All of the blocks before first_data_block are
 987                  * overhead
 988                  */
 989                 overhead = le32_to_cpu(sbi->s_es->s_first_data_block);
 990
 991                 /*
 992                  * Add the overhead attributed to the superblock and
 993                  * block group descriptors.  If the sparse superblocks
 994                  * feature is turned on, then not all groups have this.
 995                  */
 996                 for (i = 0; i < sbi->s_groups_count; i++)
 997                         overhead += ext2_bg_has_super(sb, i) +
 998                                 ext2_bg_num_gdb(sb, i);
 999
1000                 /*
1001                  * Every block group has an inode bitmap, a block
1002                  * bitmap, and an inode table.
1003                  */
1004                 overhead += (sbi->s_groups_count *
1005                              (2 + sbi->s_itb_per_group));
1006         }
1007
1008         buf->f_type = EXT2_SUPER_MAGIC;
1009         buf->f_bsize = sb->s_blocksize;
1010         buf->f_blocks = le32_to_cpu(sbi->s_es->s_blocks_count) - overhead;
1011         buf->f_bfree = ext2_count_free_blocks(sb);
1012         buf->f_bavail = buf->f_bfree - le32_to_cpu(sbi->s_es->s_r_blocks_count);
1013         if (buf->f_bfree < le32_to_cpu(sbi->s_es->s_r_blocks_count))
1014                 buf->f_bavail = 0;
1015         buf->f_files = le32_to_cpu(sbi->s_es->s_inodes_count);
1016         buf->f_ffree = ext2_count_free_inodes (sb);
1017         buf->f_namelen = EXT2_NAME_LEN;
1018         return 0;
1019 }
1020
1021 static struct super_block *ext2_get_sb(struct file_system_type *fs_type,
1022         int flags, const char *dev_name, void *data)
1023 {
1024         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1025 }
1026
1027 #ifdef CONFIG_QUOTA
1028
1029 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1030  * acquiring the locks... As quota files are never truncated and quota code
1031  * itself serializes the operations (and noone else should touch the files)
1032  * we don't have to be afraid of races */
1033 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1034                                size_t len, loff_t off)
1035 {
1036         struct inode *inode = sb_dqopt(sb)->files[type];
1037         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1038         int err = 0;
1039         int offset = off & (sb->s_blocksize - 1);
1040         int tocopy;
1041         size_t toread;
1042         struct buffer_head tmp_bh;
1043         struct buffer_head *bh;
1044         loff_t i_size = i_size_read(inode);
1045
1046         if (off > i_size)
1047                 return 0;
1048         if (off+len > i_size)
1049                 len = i_size-off;
1050         toread = len;
1051         while (toread > 0) {
1052                 tocopy = sb->s_blocksize - offset < toread ?
1053                                 sb->s_blocksize - offset : toread;
1054
1055                 tmp_bh.b_state = 0;
1056                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1057                 if (err)
1058                         return err;
1059                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1060                         memset(data, 0, tocopy);
1061                 else {
1062                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1063                         if (!bh)
1064                                 return -EIO;
1065                         memcpy(data, bh->b_data+offset, tocopy);
1066                         brelse(bh);
1067                 }
1068                 offset = 0;
1069                 toread -= tocopy;
1070                 data += tocopy;
1071                 blk++;
1072         }
1073         return len;
1074 }
1075
1076 /* Write to quotafile */
1077 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1078                                 const char *data, size_t len, loff_t off)
1079 {
1080         struct inode *inode = sb_dqopt(sb)->files[type];
1081         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1082         int err = 0;
1083         int offset = off & (sb->s_blocksize - 1);
1084         int tocopy;
1085         size_t towrite = len;
1086         struct buffer_head tmp_bh;
1087         struct buffer_head *bh;
1088
1089         down(&inode->i_sem);
1090         while (towrite > 0) {
1091                 tocopy = sb->s_blocksize - offset < towrite ?
1092                                 sb->s_blocksize - offset : towrite;
1093
1094                 tmp_bh.b_state = 0;
1095                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1096                 if (err)
1097                         goto out;
1098                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1099                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1100                 else
1101                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1102                 if (!bh) {
1103                         err = -EIO;
1104                         goto out;
1105                 }
1106                 lock_buffer(bh);
1107                 memcpy(bh->b_data+offset, data, tocopy);
1108                 flush_dcache_page(bh->b_page);
1109                 set_buffer_uptodate(bh);
1110                 mark_buffer_dirty(bh);
1111                 unlock_buffer(bh);
1112                 brelse(bh);
1113                 offset = 0;
1114                 towrite -= tocopy;
1115                 data += tocopy;
1116                 blk++;
1117         }
1118 out:
1119         if (len == towrite)
1120                 return err;
1121         if (inode->i_size < off+len-towrite)
1122                 i_size_write(inode, off+len-towrite);
1123         inode->i_version++;
1124         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1125         mark_inode_dirty(inode);
1126         up(&inode->i_sem);
1127         return len - towrite;
1128 }
1129
1130 #endif
1131
1132 static struct file_system_type ext2_fs_type = {
1133         .owner          = THIS_MODULE,
1134         .name           = "ext2",
1135         .get_sb         = ext2_get_sb,
1136         .kill_sb        = kill_block_super,
1137         .fs_flags       = FS_REQUIRES_DEV,
1138 };
1139
1140 static int __init init_ext2_fs(void)
1141 {
1142         int err = init_ext2_xattr();
1143         if (err)
1144                 return err;
1145         err = init_inodecache();
1146         if (err)
1147                 goto out1;
1148         err = register_filesystem(&ext2_fs_type);
1149         if (err)
1150                 goto out;
1151         return 0;
1152 out:
1153         destroy_inodecache();
1154 out1:
1155         exit_ext2_xattr();
1156         return err;
1157 }
1158
1159 static void __exit exit_ext2_fs(void)
1160 {
1161         unregister_filesystem(&ext2_fs_type);
1162         destroy_inodecache();
1163         exit_ext2_xattr();
1164 }
1165
1166 module_init(init_ext2_fs)
1167 module_exit(exit_ext2_fs)