fs/ext2/super.c

   1 /*
   2  *  linux/fs/ext2/super.c
   3  *
   4  * Copyright (C) 1992, 1993, 1994, 1995
   5  * Remy Card (card@masi.ibp.fr)
   6  * Laboratoire MASI - Institut Blaise Pascal
   7  * Universite Pierre et Marie Curie (Paris VI)
   8  *
   9  *  from
  10  *
  11  *  linux/fs/minix/inode.c
  12  *
  13  *  Copyright (C) 1991, 1992  Linus Torvalds
  14  *
  15  *  Big-endian to little-endian byte-swapping/bitmaps by
  16  *        David S. Miller (davem@caip.rutgers.edu), 1995
  17  */
  18
  19 #include <linux/config.h>
  20 #include <linux/module.h>
  21 #include <linux/string.h>
  22 #include <linux/fs.h>
  23 #include <linux/slab.h>
  24 #include <linux/init.h>
  25 #include <linux/blkdev.h>
  26 #include <linux/parser.h>
  27 #include <linux/random.h>
  28 #include <linux/buffer_head.h>
  29 #include <linux/smp_lock.h>
  30 #include <linux/vfs.h>
  31 #include <linux/seq_file.h>
  32 #include <linux/mount.h>
  33 #include <asm/uaccess.h>
  34 #include "ext2.h"
  35 #include "xattr.h"
  36 #include "acl.h"
  37 #include "xip.h"
  38
  39 static void ext2_sync_super(struct super_block *sb,
  40                             struct ext2_super_block *es);
  41 static int ext2_remount (struct super_block * sb, int * flags, char * data);
  42 static int ext2_statfs (struct super_block * sb, struct kstatfs * buf);
  43
  44 void ext2_error (struct super_block * sb, const char * function,
  45                  const char * fmt, ...)
  46 {
  47         va_list args;
  48         struct ext2_sb_info *sbi = EXT2_SB(sb);
  49         struct ext2_super_block *es = sbi->s_es;
  50
  51         if (!(sb->s_flags & MS_RDONLY)) {
  52                 sbi->s_mount_state |= EXT2_ERROR_FS;
  53                 es->s_state =
  54                         cpu_to_le16(le16_to_cpu(es->s_state) | EXT2_ERROR_FS);
  55                 ext2_sync_super(sb, es);
  56         }
  57
  58         va_start(args, fmt);
  59         printk(KERN_CRIT "EXT2-fs error (device %s): %s: ",sb->s_id, function);
  60         vprintk(fmt, args);
  61         printk("\n");
  62         va_end(args);
  63
  64         if (test_opt(sb, ERRORS_PANIC))
  65                 panic("EXT2-fs panic from previous error\n");
  66         if (test_opt(sb, ERRORS_RO)) {
  67                 printk("Remounting filesystem read-only\n");
  68                 sb->s_flags |= MS_RDONLY;
  69         }
  70 }
  71
  72 void ext2_warning (struct super_block * sb, const char * function,
  73                    const char * fmt, ...)
  74 {
  75         va_list args;
  76
  77         va_start(args, fmt);
  78         printk(KERN_WARNING "EXT2-fs warning (device %s): %s: ",
  79                sb->s_id, function);
  80         vprintk(fmt, args);
  81         printk("\n");
  82         va_end(args);
  83 }
  84
  85 void ext2_update_dynamic_rev(struct super_block *sb)
  86 {
  87         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
  88
  89         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
  90                 return;
  91
  92         ext2_warning(sb, __FUNCTION__,
  93                      "updating to rev %d because of new feature flag, "
  94                      "running e2fsck is recommended",
  95                      EXT2_DYNAMIC_REV);
  96
  97         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
  98         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
  99         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
 100         /* leave es->s_feature_*compat flags alone */
 101         /* es->s_uuid will be set by e2fsck if empty */
 102
 103         /*
 104          * The rest of the superblock fields should be zero, and if not it
 105          * means they are likely already in use, so leave them alone.  We
 106          * can leave it up to e2fsck to clean up any inconsistencies there.
 107          */
 108 }
 109
 110 static void ext2_put_super (struct super_block * sb)
 111 {
 112         int db_count;
 113         int i;
 114         struct ext2_sb_info *sbi = EXT2_SB(sb);
 115
 116         ext2_xattr_put_super(sb);
 117         if (!(sb->s_flags & MS_RDONLY)) {
 118                 struct ext2_super_block *es = sbi->s_es;
 119
 120                 es->s_state = cpu_to_le16(sbi->s_mount_state);
 121                 ext2_sync_super(sb, es);
 122         }
 123         db_count = sbi->s_gdb_count;
 124         for (i = 0; i < db_count; i++)
 125                 if (sbi->s_group_desc[i])
 126                         brelse (sbi->s_group_desc[i]);
 127         kfree(sbi->s_group_desc);
 128         kfree(sbi->s_debts);
 129         percpu_counter_destroy(&sbi->s_freeblocks_counter);
 130         percpu_counter_destroy(&sbi->s_freeinodes_counter);
 131         percpu_counter_destroy(&sbi->s_dirs_counter);
 132         brelse (sbi->s_sbh);
 133         sb->s_fs_info = NULL;
 134         kfree(sbi);
 135
 136         return;
 137 }
 138
 139 static kmem_cache_t * ext2_inode_cachep;
 140
 141 static struct inode *ext2_alloc_inode(struct super_block *sb)
 142 {
 143         struct ext2_inode_info *ei;
 144         ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, SLAB_KERNEL);
 145         if (!ei)
 146                 return NULL;
 147 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 148         ei->i_acl = EXT2_ACL_NOT_CACHED;
 149         ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 150 #endif
 151         ei->vfs_inode.i_version = 1;
 152         return &ei->vfs_inode;
 153 }
 154
 155 static void ext2_destroy_inode(struct inode *inode)
 156 {
 157         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
 158 }
 159
 160 static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
 161 {
 162         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
 163
 164         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 165             SLAB_CTOR_CONSTRUCTOR) {
 166                 rwlock_init(&ei->i_meta_lock);
 167 #ifdef CONFIG_EXT2_FS_XATTR
 168                 init_rwsem(&ei->xattr_sem);
 169 #endif
 170                 inode_init_once(&ei->vfs_inode);
 171         }
 172 }
 173
 174 static int init_inodecache(void)
 175 {
 176         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
 177                                              sizeof(struct ext2_inode_info),
 178                                              0, SLAB_RECLAIM_ACCOUNT,
 179                                              init_once, NULL);
 180         if (ext2_inode_cachep == NULL)
 181                 return -ENOMEM;
 182         return 0;
 183 }
 184
 185 static void destroy_inodecache(void)
 186 {
 187         if (kmem_cache_destroy(ext2_inode_cachep))
 188                 printk(KERN_INFO "ext2_inode_cache: not all structures were freed\n");
 189 }
 190
 191 static void ext2_clear_inode(struct inode *inode)
 192 {
 193 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 194         struct ext2_inode_info *ei = EXT2_I(inode);
 195
 196         if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
 197                 posix_acl_release(ei->i_acl);
 198                 ei->i_acl = EXT2_ACL_NOT_CACHED;
 199         }
 200         if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
 201                 posix_acl_release(ei->i_default_acl);
 202                 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 203         }
 204 #endif
 205 }
 206
 207 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
 208 {
 209         struct ext2_sb_info *sbi = EXT2_SB(vfs->mnt_sb);
 210
 211         if (sbi->s_mount_opt & EXT2_MOUNT_GRPID)
 212                 seq_puts(seq, ",grpid");
 213         else
 214                 seq_puts(seq, ",nogrpid");
 215
 216 #if defined(CONFIG_QUOTA)
 217         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
 218                 seq_puts(seq, ",usrquota");
 219
 220         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
 221                 seq_puts(seq, ",grpquota");
 222 #endif
 223
 224 #if defined(CONFIG_EXT2_FS_XIP)
 225         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
 226                 seq_puts(seq, ",xip");
 227 #endif
 228
 229         return 0;
 230 }
 231
 232 #ifdef CONFIG_QUOTA
 233 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
 234 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
 235 #endif
 236
 237 static struct super_operations ext2_sops = {
 238         .alloc_inode    = ext2_alloc_inode,
 239         .destroy_inode  = ext2_destroy_inode,
 240         .read_inode     = ext2_read_inode,
 241         .write_inode    = ext2_write_inode,
 242         .put_inode      = ext2_put_inode,
 243         .delete_inode   = ext2_delete_inode,
 244         .put_super      = ext2_put_super,
 245         .write_super    = ext2_write_super,
 246         .statfs         = ext2_statfs,
 247         .remount_fs     = ext2_remount,
 248         .clear_inode    = ext2_clear_inode,
 249         .show_options   = ext2_show_options,
 250 #ifdef CONFIG_QUOTA
 251         .quota_read     = ext2_quota_read,
 252         .quota_write    = ext2_quota_write,
 253 #endif
 254 };
 255
 256 /* Yes, most of these are left as NULL!!
 257  * A NULL value implies the default, which works with ext2-like file
 258  * systems, but can be improved upon.
 259  * Currently only get_parent is required.
 260  */
 261 static struct export_operations ext2_export_ops = {
 262         .get_parent = ext2_get_parent,
 263 };
 264
 265 static unsigned long get_sb_block(void **data)
 266 {
 267         unsigned long   sb_block;
 268         char            *options = (char *) *data;
 269
 270         if (!options || strncmp(options, "sb=", 3) != 0)
 271                 return 1;       /* Default location */
 272         options += 3;
 273         sb_block = simple_strtoul(options, &options, 0);
 274         if (*options && *options != ',') {
 275                 printk("EXT2-fs: Invalid sb specification: %s\n",
 276                        (char *) *data);
 277                 return 1;
 278         }
 279         if (*options == ',')
 280                 options++;
 281         *data = (void *) options;
 282         return sb_block;
 283 }
 284
 285 enum {
 286         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
 287         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
 288         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
 289         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
 290         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
 291         Opt_usrquota, Opt_grpquota
 292 };
 293
 294 static match_table_t tokens = {
 295         {Opt_bsd_df, "bsddf"},
 296         {Opt_minix_df, "minixdf"},
 297         {Opt_grpid, "grpid"},
 298         {Opt_grpid, "bsdgroups"},
 299         {Opt_nogrpid, "nogrpid"},
 300         {Opt_nogrpid, "sysvgroups"},
 301         {Opt_resgid, "resgid=%u"},
 302         {Opt_resuid, "resuid=%u"},
 303         {Opt_sb, "sb=%u"},
 304         {Opt_err_cont, "errors=continue"},
 305         {Opt_err_panic, "errors=panic"},
 306         {Opt_err_ro, "errors=remount-ro"},
 307         {Opt_nouid32, "nouid32"},
 308         {Opt_nocheck, "check=none"},
 309         {Opt_nocheck, "nocheck"},
 310         {Opt_debug, "debug"},
 311         {Opt_oldalloc, "oldalloc"},
 312         {Opt_orlov, "orlov"},
 313         {Opt_nobh, "nobh"},
 314         {Opt_user_xattr, "user_xattr"},
 315         {Opt_nouser_xattr, "nouser_xattr"},
 316         {Opt_acl, "acl"},
 317         {Opt_noacl, "noacl"},
 318         {Opt_xip, "xip"},
 319         {Opt_grpquota, "grpquota"},
 320         {Opt_ignore, "noquota"},
 321         {Opt_quota, "quota"},
 322         {Opt_usrquota, "usrquota"},
 323         {Opt_err, NULL}
 324 };
 325
 326 static int parse_options (char * options,
 327                           struct ext2_sb_info *sbi)
 328 {
 329         char * p;
 330         substring_t args[MAX_OPT_ARGS];
 331         unsigned long kind = EXT2_MOUNT_ERRORS_CONT;
 332         int option;
 333
 334         if (!options)
 335                 return 1;
 336
 337         while ((p = strsep (&options, ",")) != NULL) {
 338                 int token;
 339                 if (!*p)
 340                         continue;
 341
 342                 token = match_token(p, tokens, args);
 343                 switch (token) {
 344                 case Opt_bsd_df:
 345                         clear_opt (sbi->s_mount_opt, MINIX_DF);
 346                         break;
 347                 case Opt_minix_df:
 348                         set_opt (sbi->s_mount_opt, MINIX_DF);
 349                         break;
 350                 case Opt_grpid:
 351                         set_opt (sbi->s_mount_opt, GRPID);
 352                         break;
 353                 case Opt_nogrpid:
 354                         clear_opt (sbi->s_mount_opt, GRPID);
 355                         break;
 356                 case Opt_resuid:
 357                         if (match_int(&args[0], &option))
 358                                 return 0;
 359                         sbi->s_resuid = option;
 360                         break;
 361                 case Opt_resgid:
 362                         if (match_int(&args[0], &option))
 363                                 return 0;
 364                         sbi->s_resgid = option;
 365                         break;
 366                 case Opt_sb:
 367                         /* handled by get_sb_block() instead of here */
 368                         /* *sb_block = match_int(&args[0]); */
 369                         break;
 370                 case Opt_err_panic:
 371                         kind = EXT2_MOUNT_ERRORS_PANIC;
 372                         break;
 373                 case Opt_err_ro:
 374                         kind = EXT2_MOUNT_ERRORS_RO;
 375                         break;
 376                 case Opt_err_cont:
 377                         kind = EXT2_MOUNT_ERRORS_CONT;
 378                         break;
 379                 case Opt_nouid32:
 380                         set_opt (sbi->s_mount_opt, NO_UID32);
 381                         break;
 382                 case Opt_nocheck:
 383                         clear_opt (sbi->s_mount_opt, CHECK);
 384                         break;
 385                 case Opt_debug:
 386                         set_opt (sbi->s_mount_opt, DEBUG);
 387                         break;
 388                 case Opt_oldalloc:
 389                         set_opt (sbi->s_mount_opt, OLDALLOC);
 390                         break;
 391                 case Opt_orlov:
 392                         clear_opt (sbi->s_mount_opt, OLDALLOC);
 393                         break;
 394                 case Opt_nobh:
 395                         set_opt (sbi->s_mount_opt, NOBH);
 396                         break;
 397 #ifdef CONFIG_EXT2_FS_XATTR
 398                 case Opt_user_xattr:
 399                         set_opt (sbi->s_mount_opt, XATTR_USER);
 400                         break;
 401                 case Opt_nouser_xattr:
 402                         clear_opt (sbi->s_mount_opt, XATTR_USER);
 403                         break;
 404 #else
 405                 case Opt_user_xattr:
 406                 case Opt_nouser_xattr:
 407                         printk("EXT2 (no)user_xattr options not supported\n");
 408                         break;
 409 #endif
 410 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 411                 case Opt_acl:
 412                         set_opt(sbi->s_mount_opt, POSIX_ACL);
 413                         break;
 414                 case Opt_noacl:
 415                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
 416                         break;
 417 #else
 418                 case Opt_acl:
 419                 case Opt_noacl:
 420                         printk("EXT2 (no)acl options not supported\n");
 421                         break;
 422 #endif
 423                 case Opt_xip:
 424 #ifdef CONFIG_EXT2_FS_XIP
 425                         set_opt (sbi->s_mount_opt, XIP);
 426 #else
 427                         printk("EXT2 xip option not supported\n");
 428 #endif
 429                         break;
 430
 431 #if defined(CONFIG_QUOTA)
 432                 case Opt_quota:
 433                 case Opt_usrquota:
 434                         set_opt(sbi->s_mount_opt, USRQUOTA);
 435                         break;
 436
 437                 case Opt_grpquota:
 438                         set_opt(sbi->s_mount_opt, GRPQUOTA);
 439                         break;
 440 #else
 441                 case Opt_quota:
 442                 case Opt_usrquota:
 443                 case Opt_grpquota:
 444                         printk(KERN_ERR
 445                                 "EXT2-fs: quota operations not supported.\n");
 446
 447                         break;
 448 #endif
 449
 450                 case Opt_ignore:
 451                         break;
 452                 default:
 453                         return 0;
 454                 }
 455         }
 456         sbi->s_mount_opt |= kind;
 457         return 1;
 458 }
 459
 460 static int ext2_setup_super (struct super_block * sb,
 461                               struct ext2_super_block * es,
 462                               int read_only)
 463 {
 464         int res = 0;
 465         struct ext2_sb_info *sbi = EXT2_SB(sb);
 466
 467         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 468                 printk ("EXT2-fs warning: revision level too high, "
 469                         "forcing read-only mode\n");
 470                 res = MS_RDONLY;
 471         }
 472         if (read_only)
 473                 return res;
 474         if (!(sbi->s_mount_state & EXT2_VALID_FS))
 475                 printk ("EXT2-fs warning: mounting unchecked fs, "
 476                         "running e2fsck is recommended\n");
 477         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 478                 printk ("EXT2-fs warning: mounting fs with errors, "
 479                         "running e2fsck is recommended\n");
 480         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 481                  le16_to_cpu(es->s_mnt_count) >=
 482                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 483                 printk ("EXT2-fs warning: maximal mount count reached, "
 484                         "running e2fsck is recommended\n");
 485         else if (le32_to_cpu(es->s_checkinterval) &&
 486                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 487                 printk ("EXT2-fs warning: checktime reached, "
 488                         "running e2fsck is recommended\n");
 489         if (!le16_to_cpu(es->s_max_mnt_count))
 490                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 491         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
 492         ext2_write_super(sb);
 493         if (test_opt (sb, DEBUG))
 494                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
 495                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
 496                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 497                         sbi->s_frag_size,
 498                         sbi->s_groups_count,
 499                         EXT2_BLOCKS_PER_GROUP(sb),
 500                         EXT2_INODES_PER_GROUP(sb),
 501                         sbi->s_mount_opt);
 502         return res;
 503 }
 504
 505 static int ext2_check_descriptors (struct super_block * sb)
 506 {
 507         int i;
 508         int desc_block = 0;
 509         struct ext2_sb_info *sbi = EXT2_SB(sb);
 510         unsigned long block = le32_to_cpu(sbi->s_es->s_first_data_block);
 511         struct ext2_group_desc * gdp = NULL;
 512
 513         ext2_debug ("Checking group descriptors");
 514
 515         for (i = 0; i < sbi->s_groups_count; i++)
 516         {
 517                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
 518                         gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
 519                 if (le32_to_cpu(gdp->bg_block_bitmap) < block ||
 520                     le32_to_cpu(gdp->bg_block_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 521                 {
 522                         ext2_error (sb, "ext2_check_descriptors",
 523                                     "Block bitmap for group %d"
 524                                     " not in group (block %lu)!",
 525                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 526                         return 0;
 527                 }
 528                 if (le32_to_cpu(gdp->bg_inode_bitmap) < block ||
 529                     le32_to_cpu(gdp->bg_inode_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 530                 {
 531                         ext2_error (sb, "ext2_check_descriptors",
 532                                     "Inode bitmap for group %d"
 533                                     " not in group (block %lu)!",
 534                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 535                         return 0;
 536                 }
 537                 if (le32_to_cpu(gdp->bg_inode_table) < block ||
 538                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >=
 539                     block + EXT2_BLOCKS_PER_GROUP(sb))
 540                 {
 541                         ext2_error (sb, "ext2_check_descriptors",
 542                                     "Inode table for group %d"
 543                                     " not in group (block %lu)!",
 544                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 545                         return 0;
 546                 }
 547                 block += EXT2_BLOCKS_PER_GROUP(sb);
 548                 gdp++;
 549         }
 550         return 1;
 551 }
 552
 553 #define log2(n) ffz(~(n))
 554
 555 /*
 556  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 557  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 558  * We need to be 1 filesystem block less than the 2^32 sector limit.
 559  */
 560 static loff_t ext2_max_size(int bits)
 561 {
 562         loff_t res = EXT2_NDIR_BLOCKS;
 563         /* This constant is calculated to be the largest file size for a
 564          * dense, 4k-blocksize file such that the total number of
 565          * sectors in the file, including data and all indirect blocks,
 566          * does not exceed 2^32. */
 567         const loff_t upper_limit = 0x1ff7fffd000LL;
 568
 569         res += 1LL << (bits-2);
 570         res += 1LL << (2*(bits-2));
 571         res += 1LL << (3*(bits-2));
 572         res <<= bits;
 573         if (res > upper_limit)
 574                 res = upper_limit;
 575         return res;
 576 }
 577
 578 static unsigned long descriptor_loc(struct super_block *sb,
 579                                     unsigned long logic_sb_block,
 580                                     int nr)
 581 {
 582         struct ext2_sb_info *sbi = EXT2_SB(sb);
 583         unsigned long bg, first_data_block, first_meta_bg;
 584         int has_super = 0;
 585
 586         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 587         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 588
 589         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 590             nr < first_meta_bg)
 591                 return (logic_sb_block + nr + 1);
 592         bg = sbi->s_desc_per_block * nr;
 593         if (ext2_bg_has_super(sb, bg))
 594                 has_super = 1;
 595         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
 596 }
 597
 598 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 599 {
 600         struct buffer_head * bh;
 601         struct ext2_sb_info * sbi;
 602         struct ext2_super_block * es;
 603         struct inode *root;
 604         unsigned long block;
 605         unsigned long sb_block = get_sb_block(&data);
 606         unsigned long logic_sb_block;
 607         unsigned long offset = 0;
 608         unsigned long def_mount_opts;
 609         int blocksize = BLOCK_SIZE;
 610         int db_count;
 611         int i, j;
 612         __le32 features;
 613
 614         sbi = kmalloc(sizeof(*sbi), GFP_KERNEL);
 615         if (!sbi)
 616                 return -ENOMEM;
 617         sb->s_fs_info = sbi;
 618         memset(sbi, 0, sizeof(*sbi));
 619
 620         /*
 621          * See what the current blocksize for the device is, and
 622          * use that as the blocksize.  Otherwise (or if the blocksize
 623          * is smaller than the default) use the default.
 624          * This is important for devices that have a hardware
 625          * sectorsize that is larger than the default.
 626          */
 627         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 628         if (!blocksize) {
 629                 printk ("EXT2-fs: unable to set blocksize\n");
 630                 goto failed_sbi;
 631         }
 632
 633         /*
 634          * If the superblock doesn't start on a hardware sector boundary,
 635          * calculate the offset.
 636          */
 637         if (blocksize != BLOCK_SIZE) {
 638                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 639                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 640         } else {
 641                 logic_sb_block = sb_block;
 642         }
 643
 644         if (!(bh = sb_bread(sb, logic_sb_block))) {
 645                 printk ("EXT2-fs: unable to read superblock\n");
 646                 goto failed_sbi;
 647         }
 648         /*
 649          * Note: s_es must be initialized as soon as possible because
 650          *       some ext2 macro-instructions depend on its value
 651          */
 652         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 653         sbi->s_es = es;
 654         sb->s_magic = le16_to_cpu(es->s_magic);
 655
 656         if (sb->s_magic != EXT2_SUPER_MAGIC)
 657                 goto cantfind_ext2;
 658
 659         /* Set defaults before we parse the mount options */
 660         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 661         if (def_mount_opts & EXT2_DEFM_DEBUG)
 662                 set_opt(sbi->s_mount_opt, DEBUG);
 663         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 664                 set_opt(sbi->s_mount_opt, GRPID);
 665         if (def_mount_opts & EXT2_DEFM_UID16)
 666                 set_opt(sbi->s_mount_opt, NO_UID32);
 667         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 668                 set_opt(sbi->s_mount_opt, XATTR_USER);
 669         if (def_mount_opts & EXT2_DEFM_ACL)
 670                 set_opt(sbi->s_mount_opt, POSIX_ACL);
 671
 672         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 673                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 674         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
 675                 set_opt(sbi->s_mount_opt, ERRORS_RO);
 676
 677         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
 678         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
 679
 680         if (!parse_options ((char *) data, sbi))
 681                 goto failed_mount;
 682
 683         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 684                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 685                  MS_POSIXACL : 0);
 686
 687         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
 688                                     EXT2_MOUNT_XIP if not */
 689
 690         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 691             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 692              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 693              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 694                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
 695                        "running e2fsck is recommended\n");
 696         /*
 697          * Check feature flags regardless of the revision level, since we
 698          * previously didn't change the revision level when setting the flags,
 699          * so there is a chance incompat flags are set on a rev 0 filesystem.
 700          */
 701         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 702         if (features) {
 703                 printk("EXT2-fs: %s: couldn't mount because of "
 704                        "unsupported optional features (%x).\n",
 705                        sb->s_id, le32_to_cpu(features));
 706                 goto failed_mount;
 707         }
 708         if (!(sb->s_flags & MS_RDONLY) &&
 709             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 710                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
 711                        "unsupported optional features (%x).\n",
 712                        sb->s_id, le32_to_cpu(features));
 713                 goto failed_mount;
 714         }
 715
 716         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 717
 718         if ((ext2_use_xip(sb)) && ((blocksize != PAGE_SIZE) ||
 719                                   (sb->s_blocksize != blocksize))) {
 720                 if (!silent)
 721                         printk("XIP: Unsupported blocksize\n");
 722                 goto failed_mount;
 723         }
 724
 725         /* If the blocksize doesn't match, re-read the thing.. */
 726         if (sb->s_blocksize != blocksize) {
 727                 brelse(bh);
 728
 729                 if (!sb_set_blocksize(sb, blocksize)) {
 730                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
 731                         goto failed_sbi;
 732                 }
 733
 734                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 735                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 736                 bh = sb_bread(sb, logic_sb_block);
 737                 if(!bh) {
 738                         printk("EXT2-fs: Couldn't read superblock on "
 739                                "2nd try.\n");
 740                         goto failed_sbi;
 741                 }
 742                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 743                 sbi->s_es = es;
 744                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 745                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
 746                         goto failed_mount;
 747                 }
 748         }
 749
 750         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 751
 752         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 753                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 754                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 755         } else {
 756                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 757                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 758                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 759                     (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
 760                     (sbi->s_inode_size > blocksize)) {
 761                         printk ("EXT2-fs: unsupported inode size: %d\n",
 762                                 sbi->s_inode_size);
 763                         goto failed_mount;
 764                 }
 765         }
 766
 767         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 768                                    le32_to_cpu(es->s_log_frag_size);
 769         if (sbi->s_frag_size == 0)
 770                 goto cantfind_ext2;
 771         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
 772
 773         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 774         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 775         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 776
 777         if (EXT2_INODE_SIZE(sb) == 0)
 778                 goto cantfind_ext2;
 779         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
 780         if (sbi->s_inodes_per_block == 0)
 781                 goto cantfind_ext2;
 782         sbi->s_itb_per_group = sbi->s_inodes_per_group /
 783                                         sbi->s_inodes_per_block;
 784         sbi->s_desc_per_block = sb->s_blocksize /
 785                                         sizeof (struct ext2_group_desc);
 786         sbi->s_sbh = bh;
 787         sbi->s_mount_state = le16_to_cpu(es->s_state);
 788         sbi->s_addr_per_block_bits =
 789                 log2 (EXT2_ADDR_PER_BLOCK(sb));
 790         sbi->s_desc_per_block_bits =
 791                 log2 (EXT2_DESC_PER_BLOCK(sb));
 792
 793         if (sb->s_magic != EXT2_SUPER_MAGIC)
 794                 goto cantfind_ext2;
 795
 796         if (sb->s_blocksize != bh->b_size) {
 797                 if (!silent)
 798                         printk ("VFS: Unsupported blocksize on dev "
 799                                 "%s.\n", sb->s_id);
 800                 goto failed_mount;
 801         }
 802
 803         if (sb->s_blocksize != sbi->s_frag_size) {
 804                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
 805                         sbi->s_frag_size, sb->s_blocksize);
 806                 goto failed_mount;
 807         }
 808
 809         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
 810                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
 811                         sbi->s_blocks_per_group);
 812                 goto failed_mount;
 813         }
 814         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 815                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
 816                         sbi->s_frags_per_group);
 817                 goto failed_mount;
 818         }
 819         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
 820                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
 821                         sbi->s_inodes_per_group);
 822                 goto failed_mount;
 823         }
 824
 825         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
 826                 goto cantfind_ext2;
 827         sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) -
 828                                         le32_to_cpu(es->s_first_data_block) +
 829                                        EXT2_BLOCKS_PER_GROUP(sb) - 1) /
 830                                        EXT2_BLOCKS_PER_GROUP(sb);
 831         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
 832                    EXT2_DESC_PER_BLOCK(sb);
 833         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
 834         if (sbi->s_group_desc == NULL) {
 835                 printk ("EXT2-fs: not enough memory\n");
 836                 goto failed_mount;
 837         }
 838         percpu_counter_init(&sbi->s_freeblocks_counter);
 839         percpu_counter_init(&sbi->s_freeinodes_counter);
 840         percpu_counter_init(&sbi->s_dirs_counter);
 841         bgl_lock_init(&sbi->s_blockgroup_lock);
 842         sbi->s_debts = kmalloc(sbi->s_groups_count * sizeof(*sbi->s_debts),
 843                                GFP_KERNEL);
 844         if (!sbi->s_debts) {
 845                 printk ("EXT2-fs: not enough memory\n");
 846                 goto failed_mount_group_desc;
 847         }
 848         memset(sbi->s_debts, 0, sbi->s_groups_count * sizeof(*sbi->s_debts));
 849         for (i = 0; i < db_count; i++) {
 850                 block = descriptor_loc(sb, logic_sb_block, i);
 851                 sbi->s_group_desc[i] = sb_bread(sb, block);
 852                 if (!sbi->s_group_desc[i]) {
 853                         for (j = 0; j < i; j++)
 854                                 brelse (sbi->s_group_desc[j]);
 855                         printk ("EXT2-fs: unable to read group descriptors\n");
 856                         goto failed_mount_group_desc;
 857                 }
 858         }
 859         if (!ext2_check_descriptors (sb)) {
 860                 printk ("EXT2-fs: group descriptors corrupted!\n");
 861                 db_count = i;
 862                 goto failed_mount2;
 863         }
 864         sbi->s_gdb_count = db_count;
 865         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
 866         spin_lock_init(&sbi->s_next_gen_lock);
 867         /*
 868          * set up enough so that it can read an inode
 869          */
 870         sb->s_op = &ext2_sops;
 871         sb->s_export_op = &ext2_export_ops;
 872         sb->s_xattr = ext2_xattr_handlers;
 873         root = iget(sb, EXT2_ROOT_INO);
 874         sb->s_root = d_alloc_root(root);
 875         if (!sb->s_root) {
 876                 iput(root);
 877                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
 878                 goto failed_mount2;
 879         }
 880         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
 881                 dput(sb->s_root);
 882                 sb->s_root = NULL;
 883                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
 884                 goto failed_mount2;
 885         }
 886         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 887                 ext2_warning(sb, __FUNCTION__,
 888                         "mounting ext3 filesystem as ext2");
 889         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
 890         percpu_counter_mod(&sbi->s_freeblocks_counter,
 891                                 ext2_count_free_blocks(sb));
 892         percpu_counter_mod(&sbi->s_freeinodes_counter,
 893                                 ext2_count_free_inodes(sb));
 894         percpu_counter_mod(&sbi->s_dirs_counter,
 895                                 ext2_count_dirs(sb));
 896         return 0;
 897
 898 cantfind_ext2:
 899         if (!silent)
 900                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
 901                        sb->s_id);
 902         goto failed_mount;
 903
 904 failed_mount2:
 905         for (i = 0; i < db_count; i++)
 906                 brelse(sbi->s_group_desc[i]);
 907 failed_mount_group_desc:
 908         kfree(sbi->s_group_desc);
 909         kfree(sbi->s_debts);
 910 failed_mount:
 911         brelse(bh);
 912 failed_sbi:
 913         sb->s_fs_info = NULL;
 914         kfree(sbi);
 915         return -EINVAL;
 916 }
 917
 918 static void ext2_commit_super (struct super_block * sb,
 919                                struct ext2_super_block * es)
 920 {
 921         es->s_wtime = cpu_to_le32(get_seconds());
 922         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 923         sb->s_dirt = 0;
 924 }
 925
 926 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
 927 {
 928         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 929         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 930         es->s_wtime = cpu_to_le32(get_seconds());
 931         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 932         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
 933         sb->s_dirt = 0;
 934 }
 935
 936 /*
 937  * In the second extended file system, it is not necessary to
 938  * write the super block since we use a mapping of the
 939  * disk super block in a buffer.
 940  *
 941  * However, this function is still used to set the fs valid
 942  * flags to 0.  We need to set this flag to 0 since the fs
 943  * may have been checked while mounted and e2fsck may have
 944  * set s_state to EXT2_VALID_FS after some corrections.
 945  */
 946
 947 void ext2_write_super (struct super_block * sb)
 948 {
 949         struct ext2_super_block * es;
 950         lock_kernel();
 951         if (!(sb->s_flags & MS_RDONLY)) {
 952                 es = EXT2_SB(sb)->s_es;
 953
 954                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
 955                         ext2_debug ("setting valid to 0\n");
 956                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
 957                                                   ~EXT2_VALID_FS);
 958                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 959                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 960                         es->s_mtime = cpu_to_le32(get_seconds());
 961                         ext2_sync_super(sb, es);
 962                 } else
 963                         ext2_commit_super (sb, es);
 964         }
 965         sb->s_dirt = 0;
 966         unlock_kernel();
 967 }
 968
 969 static int ext2_remount (struct super_block * sb, int * flags, char * data)
 970 {
 971         struct ext2_sb_info * sbi = EXT2_SB(sb);
 972         struct ext2_super_block * es;
 973         unsigned long old_mount_opt = sbi->s_mount_opt;
 974         struct ext2_mount_options old_opts;
 975         unsigned long old_sb_flags;
 976         int err;
 977
 978         /* Store the old options */
 979         old_sb_flags = sb->s_flags;
 980         old_opts.s_mount_opt = sbi->s_mount_opt;
 981         old_opts.s_resuid = sbi->s_resuid;
 982         old_opts.s_resgid = sbi->s_resgid;
 983
 984         /*
 985          * Allow the "check" option to be passed as a remount option.
 986          */
 987         if (!parse_options (data, sbi)) {
 988                 err = -EINVAL;
 989                 goto restore_opts;
 990         }
 991
 992         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 993                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
 994
 995         es = sbi->s_es;
 996         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
 997             (old_mount_opt & EXT2_MOUNT_XIP)) &&
 998             invalidate_inodes(sb))
 999                 ext2_warning(sb, __FUNCTION__, "busy inodes while remounting "\
1000                              "xip remain in cache (no functional problem)");
1001         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1002                 return 0;
1003         if (*flags & MS_RDONLY) {
1004                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1005                     !(sbi->s_mount_state & EXT2_VALID_FS))
1006                         return 0;
1007                 /*
1008                  * OK, we are remounting a valid rw partition rdonly, so set
1009                  * the rdonly flag and then mark the partition as valid again.
1010                  */
1011                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1012                 es->s_mtime = cpu_to_le32(get_seconds());
1013         } else {
1014                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1015                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1016                 if (ret) {
1017                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
1018                                "unsupported optional features (%x).\n",
1019                                sb->s_id, le32_to_cpu(ret));
1020                         err = -EROFS;
1021                         goto restore_opts;
1022                 }
1023                 /*
1024                  * Mounting a RDONLY partition read-write, so reread and
1025                  * store the current valid flag.  (It may have been changed
1026                  * by e2fsck since we originally mounted the partition.)
1027                  */
1028                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1029                 if (!ext2_setup_super (sb, es, 0))
1030                         sb->s_flags &= ~MS_RDONLY;
1031         }
1032         ext2_sync_super(sb, es);
1033         return 0;
1034 restore_opts:
1035         sbi->s_mount_opt = old_opts.s_mount_opt;
1036         sbi->s_resuid = old_opts.s_resuid;
1037         sbi->s_resgid = old_opts.s_resgid;
1038         sb->s_flags = old_sb_flags;
1039         return err;
1040 }
1041
1042 static int ext2_statfs (struct super_block * sb, struct kstatfs * buf)
1043 {
1044         struct ext2_sb_info *sbi = EXT2_SB(sb);
1045         unsigned long overhead;
1046         int i;
1047
1048         if (test_opt (sb, MINIX_DF))
1049                 overhead = 0;
1050         else {
1051                 /*
1052                  * Compute the overhead (FS structures)
1053                  */
1054
1055                 /*
1056                  * All of the blocks before first_data_block are
1057                  * overhead
1058                  */
1059                 overhead = le32_to_cpu(sbi->s_es->s_first_data_block);
1060
1061                 /*
1062                  * Add the overhead attributed to the superblock and
1063                  * block group descriptors.  If the sparse superblocks
1064                  * feature is turned on, then not all groups have this.
1065                  */
1066                 for (i = 0; i < sbi->s_groups_count; i++)
1067                         overhead += ext2_bg_has_super(sb, i) +
1068                                 ext2_bg_num_gdb(sb, i);
1069
1070                 /*
1071                  * Every block group has an inode bitmap, a block
1072                  * bitmap, and an inode table.
1073                  */
1074                 overhead += (sbi->s_groups_count *
1075                              (2 + sbi->s_itb_per_group));
1076         }
1077
1078         buf->f_type = EXT2_SUPER_MAGIC;
1079         buf->f_bsize = sb->s_blocksize;
1080         buf->f_blocks = le32_to_cpu(sbi->s_es->s_blocks_count) - overhead;
1081         buf->f_bfree = ext2_count_free_blocks(sb);
1082         buf->f_bavail = buf->f_bfree - le32_to_cpu(sbi->s_es->s_r_blocks_count);
1083         if (buf->f_bfree < le32_to_cpu(sbi->s_es->s_r_blocks_count))
1084                 buf->f_bavail = 0;
1085         buf->f_files = le32_to_cpu(sbi->s_es->s_inodes_count);
1086         buf->f_ffree = ext2_count_free_inodes (sb);
1087         buf->f_namelen = EXT2_NAME_LEN;
1088         return 0;
1089 }
1090
1091 static struct super_block *ext2_get_sb(struct file_system_type *fs_type,
1092         int flags, const char *dev_name, void *data)
1093 {
1094         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1095 }
1096
1097 #ifdef CONFIG_QUOTA
1098
1099 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1100  * acquiring the locks... As quota files are never truncated and quota code
1101  * itself serializes the operations (and noone else should touch the files)
1102  * we don't have to be afraid of races */
1103 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1104                                size_t len, loff_t off)
1105 {
1106         struct inode *inode = sb_dqopt(sb)->files[type];
1107         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1108         int err = 0;
1109         int offset = off & (sb->s_blocksize - 1);
1110         int tocopy;
1111         size_t toread;
1112         struct buffer_head tmp_bh;
1113         struct buffer_head *bh;
1114         loff_t i_size = i_size_read(inode);
1115
1116         if (off > i_size)
1117                 return 0;
1118         if (off+len > i_size)
1119                 len = i_size-off;
1120         toread = len;
1121         while (toread > 0) {
1122                 tocopy = sb->s_blocksize - offset < toread ?
1123                                 sb->s_blocksize - offset : toread;
1124
1125                 tmp_bh.b_state = 0;
1126                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1127                 if (err)
1128                         return err;
1129                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1130                         memset(data, 0, tocopy);
1131                 else {
1132                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1133                         if (!bh)
1134                                 return -EIO;
1135                         memcpy(data, bh->b_data+offset, tocopy);
1136                         brelse(bh);
1137                 }
1138                 offset = 0;
1139                 toread -= tocopy;
1140                 data += tocopy;
1141                 blk++;
1142         }
1143         return len;
1144 }
1145
1146 /* Write to quotafile */
1147 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1148                                 const char *data, size_t len, loff_t off)
1149 {
1150         struct inode *inode = sb_dqopt(sb)->files[type];
1151         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1152         int err = 0;
1153         int offset = off & (sb->s_blocksize - 1);
1154         int tocopy;
1155         size_t towrite = len;
1156         struct buffer_head tmp_bh;
1157         struct buffer_head *bh;
1158
1159         mutex_lock(&inode->i_mutex);
1160         while (towrite > 0) {
1161                 tocopy = sb->s_blocksize - offset < towrite ?
1162                                 sb->s_blocksize - offset : towrite;
1163
1164                 tmp_bh.b_state = 0;
1165                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1166                 if (err)
1167                         goto out;
1168                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1169                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1170                 else
1171                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1172                 if (!bh) {
1173                         err = -EIO;
1174                         goto out;
1175                 }
1176                 lock_buffer(bh);
1177                 memcpy(bh->b_data+offset, data, tocopy);
1178                 flush_dcache_page(bh->b_page);
1179                 set_buffer_uptodate(bh);
1180                 mark_buffer_dirty(bh);
1181                 unlock_buffer(bh);
1182                 brelse(bh);
1183                 offset = 0;
1184                 towrite -= tocopy;
1185                 data += tocopy;
1186                 blk++;
1187         }
1188 out:
1189         if (len == towrite)
1190                 return err;
1191         if (inode->i_size < off+len-towrite)
1192                 i_size_write(inode, off+len-towrite);
1193         inode->i_version++;
1194         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1195         mark_inode_dirty(inode);
1196         mutex_unlock(&inode->i_mutex);
1197         return len - towrite;
1198 }
1199
1200 #endif
1201
1202 static struct file_system_type ext2_fs_type = {
1203         .owner          = THIS_MODULE,
1204         .name           = "ext2",
1205         .get_sb         = ext2_get_sb,
1206         .kill_sb        = kill_block_super,
1207         .fs_flags       = FS_REQUIRES_DEV,
1208 };
1209
1210 static int __init init_ext2_fs(void)
1211 {
1212         int err = init_ext2_xattr();
1213         if (err)
1214                 return err;
1215         err = init_inodecache();
1216         if (err)
1217                 goto out1;
1218         err = register_filesystem(&ext2_fs_type);
1219         if (err)
1220                 goto out;
1221         return 0;
1222 out:
1223         destroy_inodecache();
1224 out1:
1225         exit_ext2_xattr();
1226         return err;
1227 }
1228
1229 static void __exit exit_ext2_fs(void)
1230 {
1231         unregister_filesystem(&ext2_fs_type);
1232         destroy_inodecache();
1233         exit_ext2_xattr();
1234 }
1235
1236 module_init(init_ext2_fs)
1237 module_exit(exit_ext2_fs)