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