git.oblomov.eu Git - linux-2.6/blob - fs/ext2/super.c

   1 /*
   2  *  linux/fs/ext2/super.c
   3  *
   4  * Copyright (C) 1992, 1993, 1994, 1995
   5  * Remy Card (card@masi.ibp.fr)
   6  * Laboratoire MASI - Institut Blaise Pascal
   7  * Universite Pierre et Marie Curie (Paris VI)
   8  *
   9  *  from
  10  *
  11  *  linux/fs/minix/inode.c
  12  *
  13  *  Copyright (C) 1991, 1992  Linus Torvalds
  14  *
  15  *  Big-endian to little-endian byte-swapping/bitmaps by
  16  *        David S. Miller (davem@caip.rutgers.edu), 1995
  17  */
  18
  19 #include <linux/config.h>
  20 #include <linux/module.h>
  21 #include <linux/string.h>
  22 #include <linux/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 struct dentry *ext2_get_parent(struct dentry *child);
 262 static struct export_operations ext2_export_ops = {
 263         .get_parent = ext2_get_parent,
 264 };
 265
 266 static unsigned long get_sb_block(void **data)
 267 {
 268         unsigned long   sb_block;
 269         char            *options = (char *) *data;
 270
 271         if (!options || strncmp(options, "sb=", 3) != 0)
 272                 return 1;       /* Default location */
 273         options += 3;
 274         sb_block = simple_strtoul(options, &options, 0);
 275         if (*options && *options != ',') {
 276                 printk("EXT2-fs: Invalid sb specification: %s\n",
 277                        (char *) *data);
 278                 return 1;
 279         }
 280         if (*options == ',')
 281                 options++;
 282         *data = (void *) options;
 283         return sb_block;
 284 }
 285
 286 enum {
 287         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
 288         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
 289         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
 290         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
 291         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
 292         Opt_usrquota, Opt_grpquota
 293 };
 294
 295 static match_table_t tokens = {
 296         {Opt_bsd_df, "bsddf"},
 297         {Opt_minix_df, "minixdf"},
 298         {Opt_grpid, "grpid"},
 299         {Opt_grpid, "bsdgroups"},
 300         {Opt_nogrpid, "nogrpid"},
 301         {Opt_nogrpid, "sysvgroups"},
 302         {Opt_resgid, "resgid=%u"},
 303         {Opt_resuid, "resuid=%u"},
 304         {Opt_sb, "sb=%u"},
 305         {Opt_err_cont, "errors=continue"},
 306         {Opt_err_panic, "errors=panic"},
 307         {Opt_err_ro, "errors=remount-ro"},
 308         {Opt_nouid32, "nouid32"},
 309         {Opt_nocheck, "check=none"},
 310         {Opt_nocheck, "nocheck"},
 311         {Opt_debug, "debug"},
 312         {Opt_oldalloc, "oldalloc"},
 313         {Opt_orlov, "orlov"},
 314         {Opt_nobh, "nobh"},
 315         {Opt_user_xattr, "user_xattr"},
 316         {Opt_nouser_xattr, "nouser_xattr"},
 317         {Opt_acl, "acl"},
 318         {Opt_noacl, "noacl"},
 319         {Opt_xip, "xip"},
 320         {Opt_grpquota, "grpquota"},
 321         {Opt_ignore, "noquota"},
 322         {Opt_quota, "quota"},
 323         {Opt_usrquota, "usrquota"},
 324         {Opt_err, NULL}
 325 };
 326
 327 static int parse_options (char * options,
 328                           struct ext2_sb_info *sbi)
 329 {
 330         char * p;
 331         substring_t args[MAX_OPT_ARGS];
 332         unsigned long kind = EXT2_MOUNT_ERRORS_CONT;
 333         int option;
 334
 335         if (!options)
 336                 return 1;
 337
 338         while ((p = strsep (&options, ",")) != NULL) {
 339                 int token;
 340                 if (!*p)
 341                         continue;
 342
 343                 token = match_token(p, tokens, args);
 344                 switch (token) {
 345                 case Opt_bsd_df:
 346                         clear_opt (sbi->s_mount_opt, MINIX_DF);
 347                         break;
 348                 case Opt_minix_df:
 349                         set_opt (sbi->s_mount_opt, MINIX_DF);
 350                         break;
 351                 case Opt_grpid:
 352                         set_opt (sbi->s_mount_opt, GRPID);
 353                         break;
 354                 case Opt_nogrpid:
 355                         clear_opt (sbi->s_mount_opt, GRPID);
 356                         break;
 357                 case Opt_resuid:
 358                         if (match_int(&args[0], &option))
 359                                 return 0;
 360                         sbi->s_resuid = option;
 361                         break;
 362                 case Opt_resgid:
 363                         if (match_int(&args[0], &option))
 364                                 return 0;
 365                         sbi->s_resgid = option;
 366                         break;
 367                 case Opt_sb:
 368                         /* handled by get_sb_block() instead of here */
 369                         /* *sb_block = match_int(&args[0]); */
 370                         break;
 371                 case Opt_err_panic:
 372                         kind = EXT2_MOUNT_ERRORS_PANIC;
 373                         break;
 374                 case Opt_err_ro:
 375                         kind = EXT2_MOUNT_ERRORS_RO;
 376                         break;
 377                 case Opt_err_cont:
 378                         kind = EXT2_MOUNT_ERRORS_CONT;
 379                         break;
 380                 case Opt_nouid32:
 381                         set_opt (sbi->s_mount_opt, NO_UID32);
 382                         break;
 383                 case Opt_nocheck:
 384                         clear_opt (sbi->s_mount_opt, CHECK);
 385                         break;
 386                 case Opt_debug:
 387                         set_opt (sbi->s_mount_opt, DEBUG);
 388                         break;
 389                 case Opt_oldalloc:
 390                         set_opt (sbi->s_mount_opt, OLDALLOC);
 391                         break;
 392                 case Opt_orlov:
 393                         clear_opt (sbi->s_mount_opt, OLDALLOC);
 394                         break;
 395                 case Opt_nobh:
 396                         set_opt (sbi->s_mount_opt, NOBH);
 397                         break;
 398 #ifdef CONFIG_EXT2_FS_XATTR
 399                 case Opt_user_xattr:
 400                         set_opt (sbi->s_mount_opt, XATTR_USER);
 401                         break;
 402                 case Opt_nouser_xattr:
 403                         clear_opt (sbi->s_mount_opt, XATTR_USER);
 404                         break;
 405 #else
 406                 case Opt_user_xattr:
 407                 case Opt_nouser_xattr:
 408                         printk("EXT2 (no)user_xattr options not supported\n");
 409                         break;
 410 #endif
 411 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 412                 case Opt_acl:
 413                         set_opt(sbi->s_mount_opt, POSIX_ACL);
 414                         break;
 415                 case Opt_noacl:
 416                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
 417                         break;
 418 #else
 419                 case Opt_acl:
 420                 case Opt_noacl:
 421                         printk("EXT2 (no)acl options not supported\n");
 422                         break;
 423 #endif
 424                 case Opt_xip:
 425 #ifdef CONFIG_EXT2_FS_XIP
 426                         set_opt (sbi->s_mount_opt, XIP);
 427 #else
 428                         printk("EXT2 xip option not supported\n");
 429 #endif
 430                         break;
 431
 432 #if defined(CONFIG_QUOTA)
 433                 case Opt_quota:
 434                 case Opt_usrquota:
 435                         set_opt(sbi->s_mount_opt, USRQUOTA);
 436                         break;
 437
 438                 case Opt_grpquota:
 439                         set_opt(sbi->s_mount_opt, GRPQUOTA);
 440                         break;
 441 #else
 442                 case Opt_quota:
 443                 case Opt_usrquota:
 444                 case Opt_grpquota:
 445                         printk(KERN_ERR
 446                                 "EXT2-fs: quota operations not supported.\n");
 447
 448                         break;
 449 #endif
 450
 451                 case Opt_ignore:
 452                         break;
 453                 default:
 454                         return 0;
 455                 }
 456         }
 457         sbi->s_mount_opt |= kind;
 458         return 1;
 459 }
 460
 461 static int ext2_setup_super (struct super_block * sb,
 462                               struct ext2_super_block * es,
 463                               int read_only)
 464 {
 465         int res = 0;
 466         struct ext2_sb_info *sbi = EXT2_SB(sb);
 467
 468         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 469                 printk ("EXT2-fs warning: revision level too high, "
 470                         "forcing read-only mode\n");
 471                 res = MS_RDONLY;
 472         }
 473         if (read_only)
 474                 return res;
 475         if (!(sbi->s_mount_state & EXT2_VALID_FS))
 476                 printk ("EXT2-fs warning: mounting unchecked fs, "
 477                         "running e2fsck is recommended\n");
 478         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 479                 printk ("EXT2-fs warning: mounting fs with errors, "
 480                         "running e2fsck is recommended\n");
 481         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 482                  le16_to_cpu(es->s_mnt_count) >=
 483                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 484                 printk ("EXT2-fs warning: maximal mount count reached, "
 485                         "running e2fsck is recommended\n");
 486         else if (le32_to_cpu(es->s_checkinterval) &&
 487                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 488                 printk ("EXT2-fs warning: checktime reached, "
 489                         "running e2fsck is recommended\n");
 490         if (!le16_to_cpu(es->s_max_mnt_count))
 491                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 492         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
 493         ext2_write_super(sb);
 494         if (test_opt (sb, DEBUG))
 495                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
 496                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
 497                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 498                         sbi->s_frag_size,
 499                         sbi->s_groups_count,
 500                         EXT2_BLOCKS_PER_GROUP(sb),
 501                         EXT2_INODES_PER_GROUP(sb),
 502                         sbi->s_mount_opt);
 503         return res;
 504 }
 505
 506 static int ext2_check_descriptors (struct super_block * sb)
 507 {
 508         int i;
 509         int desc_block = 0;
 510         struct ext2_sb_info *sbi = EXT2_SB(sb);
 511         unsigned long block = le32_to_cpu(sbi->s_es->s_first_data_block);
 512         struct ext2_group_desc * gdp = NULL;
 513
 514         ext2_debug ("Checking group descriptors");
 515
 516         for (i = 0; i < sbi->s_groups_count; i++)
 517         {
 518                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
 519                         gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
 520                 if (le32_to_cpu(gdp->bg_block_bitmap) < block ||
 521                     le32_to_cpu(gdp->bg_block_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 522                 {
 523                         ext2_error (sb, "ext2_check_descriptors",
 524                                     "Block bitmap for group %d"
 525                                     " not in group (block %lu)!",
 526                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 527                         return 0;
 528                 }
 529                 if (le32_to_cpu(gdp->bg_inode_bitmap) < block ||
 530                     le32_to_cpu(gdp->bg_inode_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 531                 {
 532                         ext2_error (sb, "ext2_check_descriptors",
 533                                     "Inode bitmap for group %d"
 534                                     " not in group (block %lu)!",
 535                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 536                         return 0;
 537                 }
 538                 if (le32_to_cpu(gdp->bg_inode_table) < block ||
 539                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >=
 540                     block + EXT2_BLOCKS_PER_GROUP(sb))
 541                 {
 542                         ext2_error (sb, "ext2_check_descriptors",
 543                                     "Inode table for group %d"
 544                                     " not in group (block %lu)!",
 545                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 546                         return 0;
 547                 }
 548                 block += EXT2_BLOCKS_PER_GROUP(sb);
 549                 gdp++;
 550         }
 551         return 1;
 552 }
 553
 554 #define log2(n) ffz(~(n))
 555
 556 /*
 557  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 558  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 559  * We need to be 1 filesystem block less than the 2^32 sector limit.
 560  */
 561 static loff_t ext2_max_size(int bits)
 562 {
 563         loff_t res = EXT2_NDIR_BLOCKS;
 564         /* This constant is calculated to be the largest file size for a
 565          * dense, 4k-blocksize file such that the total number of
 566          * sectors in the file, including data and all indirect blocks,
 567          * does not exceed 2^32. */
 568         const loff_t upper_limit = 0x1ff7fffd000LL;
 569
 570         res += 1LL << (bits-2);
 571         res += 1LL << (2*(bits-2));
 572         res += 1LL << (3*(bits-2));
 573         res <<= bits;
 574         if (res > upper_limit)
 575                 res = upper_limit;
 576         return res;
 577 }
 578
 579 static unsigned long descriptor_loc(struct super_block *sb,
 580                                     unsigned long logic_sb_block,
 581                                     int nr)
 582 {
 583         struct ext2_sb_info *sbi = EXT2_SB(sb);
 584         unsigned long bg, first_data_block, first_meta_bg;
 585         int has_super = 0;
 586
 587         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 588         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 589
 590         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 591             nr < first_meta_bg)
 592                 return (logic_sb_block + nr + 1);
 593         bg = sbi->s_desc_per_block * nr;
 594         if (ext2_bg_has_super(sb, bg))
 595                 has_super = 1;
 596         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
 597 }
 598
 599 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 600 {
 601         struct buffer_head * bh;
 602         struct ext2_sb_info * sbi;
 603         struct ext2_super_block * es;
 604         struct inode *root;
 605         unsigned long block;
 606         unsigned long sb_block = get_sb_block(&data);
 607         unsigned long logic_sb_block;
 608         unsigned long offset = 0;
 609         unsigned long def_mount_opts;
 610         int blocksize = BLOCK_SIZE;
 611         int db_count;
 612         int i, j;
 613         __le32 features;
 614
 615         sbi = kmalloc(sizeof(*sbi), GFP_KERNEL);
 616         if (!sbi)
 617                 return -ENOMEM;
 618         sb->s_fs_info = sbi;
 619         memset(sbi, 0, sizeof(*sbi));
 620
 621         /*
 622          * See what the current blocksize for the device is, and
 623          * use that as the blocksize.  Otherwise (or if the blocksize
 624          * is smaller than the default) use the default.
 625          * This is important for devices that have a hardware
 626          * sectorsize that is larger than the default.
 627          */
 628         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 629         if (!blocksize) {
 630                 printk ("EXT2-fs: unable to set blocksize\n");
 631                 goto failed_sbi;
 632         }
 633
 634         /*
 635          * If the superblock doesn't start on a hardware sector boundary,
 636          * calculate the offset.
 637          */
 638         if (blocksize != BLOCK_SIZE) {
 639                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 640                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 641         } else {
 642                 logic_sb_block = sb_block;
 643         }
 644
 645         if (!(bh = sb_bread(sb, logic_sb_block))) {
 646                 printk ("EXT2-fs: unable to read superblock\n");
 647                 goto failed_sbi;
 648         }
 649         /*
 650          * Note: s_es must be initialized as soon as possible because
 651          *       some ext2 macro-instructions depend on its value
 652          */
 653         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 654         sbi->s_es = es;
 655         sb->s_magic = le16_to_cpu(es->s_magic);
 656
 657         if (sb->s_magic != EXT2_SUPER_MAGIC)
 658                 goto cantfind_ext2;
 659
 660         /* Set defaults before we parse the mount options */
 661         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 662         if (def_mount_opts & EXT2_DEFM_DEBUG)
 663                 set_opt(sbi->s_mount_opt, DEBUG);
 664         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 665                 set_opt(sbi->s_mount_opt, GRPID);
 666         if (def_mount_opts & EXT2_DEFM_UID16)
 667                 set_opt(sbi->s_mount_opt, NO_UID32);
 668         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 669                 set_opt(sbi->s_mount_opt, XATTR_USER);
 670         if (def_mount_opts & EXT2_DEFM_ACL)
 671                 set_opt(sbi->s_mount_opt, POSIX_ACL);
 672
 673         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 674                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 675         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
 676                 set_opt(sbi->s_mount_opt, ERRORS_RO);
 677
 678         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
 679         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
 680
 681         if (!parse_options ((char *) data, sbi))
 682                 goto failed_mount;
 683
 684         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 685                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 686                  MS_POSIXACL : 0);
 687
 688         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
 689                                     EXT2_MOUNT_XIP if not */
 690
 691         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 692             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 693              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 694              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 695                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
 696                        "running e2fsck is recommended\n");
 697         /*
 698          * Check feature flags regardless of the revision level, since we
 699          * previously didn't change the revision level when setting the flags,
 700          * so there is a chance incompat flags are set on a rev 0 filesystem.
 701          */
 702         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 703         if (features) {
 704                 printk("EXT2-fs: %s: couldn't mount because of "
 705                        "unsupported optional features (%x).\n",
 706                        sb->s_id, le32_to_cpu(features));
 707                 goto failed_mount;
 708         }
 709         if (!(sb->s_flags & MS_RDONLY) &&
 710             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 711                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
 712                        "unsupported optional features (%x).\n",
 713                        sb->s_id, le32_to_cpu(features));
 714                 goto failed_mount;
 715         }
 716
 717         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 718
 719         if ((ext2_use_xip(sb)) && ((blocksize != PAGE_SIZE) ||
 720                                   (sb->s_blocksize != blocksize))) {
 721                 if (!silent)
 722                         printk("XIP: Unsupported blocksize\n");
 723                 goto failed_mount;
 724         }
 725
 726         /* If the blocksize doesn't match, re-read the thing.. */
 727         if (sb->s_blocksize != blocksize) {
 728                 brelse(bh);
 729
 730                 if (!sb_set_blocksize(sb, blocksize)) {
 731                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
 732                         goto failed_sbi;
 733                 }
 734
 735                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 736                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 737                 bh = sb_bread(sb, logic_sb_block);
 738                 if(!bh) {
 739                         printk("EXT2-fs: Couldn't read superblock on "
 740                                "2nd try.\n");
 741                         goto failed_sbi;
 742                 }
 743                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 744                 sbi->s_es = es;
 745                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 746                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
 747                         goto failed_mount;
 748                 }
 749         }
 750
 751         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 752
 753         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 754                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 755                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 756         } else {
 757                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 758                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 759                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 760                     (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
 761                     (sbi->s_inode_size > blocksize)) {
 762                         printk ("EXT2-fs: unsupported inode size: %d\n",
 763                                 sbi->s_inode_size);
 764                         goto failed_mount;
 765                 }
 766         }
 767
 768         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 769                                    le32_to_cpu(es->s_log_frag_size);
 770         if (sbi->s_frag_size == 0)
 771                 goto cantfind_ext2;
 772         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
 773
 774         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 775         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 776         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 777
 778         if (EXT2_INODE_SIZE(sb) == 0)
 779                 goto cantfind_ext2;
 780         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
 781         if (sbi->s_inodes_per_block == 0)
 782                 goto cantfind_ext2;
 783         sbi->s_itb_per_group = sbi->s_inodes_per_group /
 784                                         sbi->s_inodes_per_block;
 785         sbi->s_desc_per_block = sb->s_blocksize /
 786                                         sizeof (struct ext2_group_desc);
 787         sbi->s_sbh = bh;
 788         sbi->s_mount_state = le16_to_cpu(es->s_state);
 789         sbi->s_addr_per_block_bits =
 790                 log2 (EXT2_ADDR_PER_BLOCK(sb));
 791         sbi->s_desc_per_block_bits =
 792                 log2 (EXT2_DESC_PER_BLOCK(sb));
 793
 794         if (sb->s_magic != EXT2_SUPER_MAGIC)
 795                 goto cantfind_ext2;
 796
 797         if (sb->s_blocksize != bh->b_size) {
 798                 if (!silent)
 799                         printk ("VFS: Unsupported blocksize on dev "
 800                                 "%s.\n", sb->s_id);
 801                 goto failed_mount;
 802         }
 803
 804         if (sb->s_blocksize != sbi->s_frag_size) {
 805                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
 806                         sbi->s_frag_size, sb->s_blocksize);
 807                 goto failed_mount;
 808         }
 809
 810         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
 811                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
 812                         sbi->s_blocks_per_group);
 813                 goto failed_mount;
 814         }
 815         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 816                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
 817                         sbi->s_frags_per_group);
 818                 goto failed_mount;
 819         }
 820         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
 821                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
 822                         sbi->s_inodes_per_group);
 823                 goto failed_mount;
 824         }
 825
 826         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
 827                 goto cantfind_ext2;
 828         sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) -
 829                                         le32_to_cpu(es->s_first_data_block) +
 830                                        EXT2_BLOCKS_PER_GROUP(sb) - 1) /
 831                                        EXT2_BLOCKS_PER_GROUP(sb);
 832         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
 833                    EXT2_DESC_PER_BLOCK(sb);
 834         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
 835         if (sbi->s_group_desc == NULL) {
 836                 printk ("EXT2-fs: not enough memory\n");
 837                 goto failed_mount;
 838         }
 839         percpu_counter_init(&sbi->s_freeblocks_counter);
 840         percpu_counter_init(&sbi->s_freeinodes_counter);
 841         percpu_counter_init(&sbi->s_dirs_counter);
 842         bgl_lock_init(&sbi->s_blockgroup_lock);
 843         sbi->s_debts = kmalloc(sbi->s_groups_count * sizeof(*sbi->s_debts),
 844                                GFP_KERNEL);
 845         if (!sbi->s_debts) {
 846                 printk ("EXT2-fs: not enough memory\n");
 847                 goto failed_mount_group_desc;
 848         }
 849         memset(sbi->s_debts, 0, sbi->s_groups_count * sizeof(*sbi->s_debts));
 850         for (i = 0; i < db_count; i++) {
 851                 block = descriptor_loc(sb, logic_sb_block, i);
 852                 sbi->s_group_desc[i] = sb_bread(sb, block);
 853                 if (!sbi->s_group_desc[i]) {
 854                         for (j = 0; j < i; j++)
 855                                 brelse (sbi->s_group_desc[j]);
 856                         printk ("EXT2-fs: unable to read group descriptors\n");
 857                         goto failed_mount_group_desc;
 858                 }
 859         }
 860         if (!ext2_check_descriptors (sb)) {
 861                 printk ("EXT2-fs: group descriptors corrupted!\n");
 862                 db_count = i;
 863                 goto failed_mount2;
 864         }
 865         sbi->s_gdb_count = db_count;
 866         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
 867         spin_lock_init(&sbi->s_next_gen_lock);
 868         /*
 869          * set up enough so that it can read an inode
 870          */
 871         sb->s_op = &ext2_sops;
 872         sb->s_export_op = &ext2_export_ops;
 873         sb->s_xattr = ext2_xattr_handlers;
 874         root = iget(sb, EXT2_ROOT_INO);
 875         sb->s_root = d_alloc_root(root);
 876         if (!sb->s_root) {
 877                 iput(root);
 878                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
 879                 goto failed_mount2;
 880         }
 881         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
 882                 dput(sb->s_root);
 883                 sb->s_root = NULL;
 884                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
 885                 goto failed_mount2;
 886         }
 887         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 888                 ext2_warning(sb, __FUNCTION__,
 889                         "mounting ext3 filesystem as ext2");
 890         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
 891         percpu_counter_mod(&sbi->s_freeblocks_counter,
 892                                 ext2_count_free_blocks(sb));
 893         percpu_counter_mod(&sbi->s_freeinodes_counter,
 894                                 ext2_count_free_inodes(sb));
 895         percpu_counter_mod(&sbi->s_dirs_counter,
 896                                 ext2_count_dirs(sb));
 897         return 0;
 898
 899 cantfind_ext2:
 900         if (!silent)
 901                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
 902                        sb->s_id);
 903         goto failed_mount;
 904
 905 failed_mount2:
 906         for (i = 0; i < db_count; i++)
 907                 brelse(sbi->s_group_desc[i]);
 908 failed_mount_group_desc:
 909         kfree(sbi->s_group_desc);
 910         kfree(sbi->s_debts);
 911 failed_mount:
 912         brelse(bh);
 913 failed_sbi:
 914         sb->s_fs_info = NULL;
 915         kfree(sbi);
 916         return -EINVAL;
 917 }
 918
 919 static void ext2_commit_super (struct super_block * sb,
 920                                struct ext2_super_block * es)
 921 {
 922         es->s_wtime = cpu_to_le32(get_seconds());
 923         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 924         sb->s_dirt = 0;
 925 }
 926
 927 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
 928 {
 929         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 930         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 931         es->s_wtime = cpu_to_le32(get_seconds());
 932         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 933         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
 934         sb->s_dirt = 0;
 935 }
 936
 937 /*
 938  * In the second extended file system, it is not necessary to
 939  * write the super block since we use a mapping of the
 940  * disk super block in a buffer.
 941  *
 942  * However, this function is still used to set the fs valid
 943  * flags to 0.  We need to set this flag to 0 since the fs
 944  * may have been checked while mounted and e2fsck may have
 945  * set s_state to EXT2_VALID_FS after some corrections.
 946  */
 947
 948 void ext2_write_super (struct super_block * sb)
 949 {
 950         struct ext2_super_block * es;
 951         lock_kernel();
 952         if (!(sb->s_flags & MS_RDONLY)) {
 953                 es = EXT2_SB(sb)->s_es;
 954
 955                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
 956                         ext2_debug ("setting valid to 0\n");
 957                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
 958                                                   ~EXT2_VALID_FS);
 959                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 960                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 961                         es->s_mtime = cpu_to_le32(get_seconds());
 962                         ext2_sync_super(sb, es);
 963                 } else
 964                         ext2_commit_super (sb, es);
 965         }
 966         sb->s_dirt = 0;
 967         unlock_kernel();
 968 }
 969
 970 static int ext2_remount (struct super_block * sb, int * flags, char * data)
 971 {
 972         struct ext2_sb_info * sbi = EXT2_SB(sb);
 973         struct ext2_super_block * es;
 974         unsigned long old_mount_opt = sbi->s_mount_opt;
 975         struct ext2_mount_options old_opts;
 976         unsigned long old_sb_flags;
 977         int err;
 978
 979         /* Store the old options */
 980         old_sb_flags = sb->s_flags;
 981         old_opts.s_mount_opt = sbi->s_mount_opt;
 982         old_opts.s_resuid = sbi->s_resuid;
 983         old_opts.s_resgid = sbi->s_resgid;
 984
 985         /*
 986          * Allow the "check" option to be passed as a remount option.
 987          */
 988         if (!parse_options (data, sbi)) {
 989                 err = -EINVAL;
 990                 goto restore_opts;
 991         }
 992
 993         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 994                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
 995
 996         es = sbi->s_es;
 997         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
 998             (old_mount_opt & EXT2_MOUNT_XIP)) &&
 999             invalidate_inodes(sb))
1000                 ext2_warning(sb, __FUNCTION__, "busy inodes while remounting "\
1001                              "xip remain in cache (no functional problem)");
1002         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1003                 return 0;
1004         if (*flags & MS_RDONLY) {
1005                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1006                     !(sbi->s_mount_state & EXT2_VALID_FS))
1007                         return 0;
1008                 /*
1009                  * OK, we are remounting a valid rw partition rdonly, so set
1010                  * the rdonly flag and then mark the partition as valid again.
1011                  */
1012                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1013                 es->s_mtime = cpu_to_le32(get_seconds());
1014         } else {
1015                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1016                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1017                 if (ret) {
1018                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
1019                                "unsupported optional features (%x).\n",
1020                                sb->s_id, le32_to_cpu(ret));
1021                         err = -EROFS;
1022                         goto restore_opts;
1023                 }
1024                 /*
1025                  * Mounting a RDONLY partition read-write, so reread and
1026                  * store the current valid flag.  (It may have been changed
1027                  * by e2fsck since we originally mounted the partition.)
1028                  */
1029                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1030                 if (!ext2_setup_super (sb, es, 0))
1031                         sb->s_flags &= ~MS_RDONLY;
1032         }
1033         ext2_sync_super(sb, es);
1034         return 0;
1035 restore_opts:
1036         sbi->s_mount_opt = old_opts.s_mount_opt;
1037         sbi->s_resuid = old_opts.s_resuid;
1038         sbi->s_resgid = old_opts.s_resgid;
1039         sb->s_flags = old_sb_flags;
1040         return err;
1041 }
1042
1043 static int ext2_statfs (struct super_block * sb, struct kstatfs * buf)
1044 {
1045         struct ext2_sb_info *sbi = EXT2_SB(sb);
1046         unsigned long overhead;
1047         int i;
1048
1049         if (test_opt (sb, MINIX_DF))
1050                 overhead = 0;
1051         else {
1052                 /*
1053                  * Compute the overhead (FS structures)
1054                  */
1055
1056                 /*
1057                  * All of the blocks before first_data_block are
1058                  * overhead
1059                  */
1060                 overhead = le32_to_cpu(sbi->s_es->s_first_data_block);
1061
1062                 /*
1063                  * Add the overhead attributed to the superblock and
1064                  * block group descriptors.  If the sparse superblocks
1065                  * feature is turned on, then not all groups have this.
1066                  */
1067                 for (i = 0; i < sbi->s_groups_count; i++)
1068                         overhead += ext2_bg_has_super(sb, i) +
1069                                 ext2_bg_num_gdb(sb, i);
1070
1071                 /*
1072                  * Every block group has an inode bitmap, a block
1073                  * bitmap, and an inode table.
1074                  */
1075                 overhead += (sbi->s_groups_count *
1076                              (2 + sbi->s_itb_per_group));
1077         }
1078
1079         buf->f_type = EXT2_SUPER_MAGIC;
1080         buf->f_bsize = sb->s_blocksize;
1081         buf->f_blocks = le32_to_cpu(sbi->s_es->s_blocks_count) - overhead;
1082         buf->f_bfree = ext2_count_free_blocks(sb);
1083         buf->f_bavail = buf->f_bfree - le32_to_cpu(sbi->s_es->s_r_blocks_count);
1084         if (buf->f_bfree < le32_to_cpu(sbi->s_es->s_r_blocks_count))
1085                 buf->f_bavail = 0;
1086         buf->f_files = le32_to_cpu(sbi->s_es->s_inodes_count);
1087         buf->f_ffree = ext2_count_free_inodes (sb);
1088         buf->f_namelen = EXT2_NAME_LEN;
1089         return 0;
1090 }
1091
1092 static struct super_block *ext2_get_sb(struct file_system_type *fs_type,
1093         int flags, const char *dev_name, void *data)
1094 {
1095         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1096 }
1097
1098 #ifdef CONFIG_QUOTA
1099
1100 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1101  * acquiring the locks... As quota files are never truncated and quota code
1102  * itself serializes the operations (and noone else should touch the files)
1103  * we don't have to be afraid of races */
1104 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1105                                size_t len, loff_t off)
1106 {
1107         struct inode *inode = sb_dqopt(sb)->files[type];
1108         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1109         int err = 0;
1110         int offset = off & (sb->s_blocksize - 1);
1111         int tocopy;
1112         size_t toread;
1113         struct buffer_head tmp_bh;
1114         struct buffer_head *bh;
1115         loff_t i_size = i_size_read(inode);
1116
1117         if (off > i_size)
1118                 return 0;
1119         if (off+len > i_size)
1120                 len = i_size-off;
1121         toread = len;
1122         while (toread > 0) {
1123                 tocopy = sb->s_blocksize - offset < toread ?
1124                                 sb->s_blocksize - offset : toread;
1125
1126                 tmp_bh.b_state = 0;
1127                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1128                 if (err)
1129                         return err;
1130                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1131                         memset(data, 0, tocopy);
1132                 else {
1133                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1134                         if (!bh)
1135                                 return -EIO;
1136                         memcpy(data, bh->b_data+offset, tocopy);
1137                         brelse(bh);
1138                 }
1139                 offset = 0;
1140                 toread -= tocopy;
1141                 data += tocopy;
1142                 blk++;
1143         }
1144         return len;
1145 }
1146
1147 /* Write to quotafile */
1148 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1149                                 const char *data, size_t len, loff_t off)
1150 {
1151         struct inode *inode = sb_dqopt(sb)->files[type];
1152         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1153         int err = 0;
1154         int offset = off & (sb->s_blocksize - 1);
1155         int tocopy;
1156         size_t towrite = len;
1157         struct buffer_head tmp_bh;
1158         struct buffer_head *bh;
1159
1160         mutex_lock(&inode->i_mutex);
1161         while (towrite > 0) {
1162                 tocopy = sb->s_blocksize - offset < towrite ?
1163                                 sb->s_blocksize - offset : towrite;
1164
1165                 tmp_bh.b_state = 0;
1166                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1167                 if (err)
1168                         goto out;
1169                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1170                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1171                 else
1172                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1173                 if (!bh) {
1174                         err = -EIO;
1175                         goto out;
1176                 }
1177                 lock_buffer(bh);
1178                 memcpy(bh->b_data+offset, data, tocopy);
1179                 flush_dcache_page(bh->b_page);
1180                 set_buffer_uptodate(bh);
1181                 mark_buffer_dirty(bh);
1182                 unlock_buffer(bh);
1183                 brelse(bh);
1184                 offset = 0;
1185                 towrite -= tocopy;
1186                 data += tocopy;
1187                 blk++;
1188         }
1189 out:
1190         if (len == towrite)
1191                 return err;
1192         if (inode->i_size < off+len-towrite)
1193                 i_size_write(inode, off+len-towrite);
1194         inode->i_version++;
1195         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1196         mark_inode_dirty(inode);
1197         mutex_unlock(&inode->i_mutex);
1198         return len - towrite;
1199 }
1200
1201 #endif
1202
1203 static struct file_system_type ext2_fs_type = {
1204         .owner          = THIS_MODULE,
1205         .name           = "ext2",
1206         .get_sb         = ext2_get_sb,
1207         .kill_sb        = kill_block_super,
1208         .fs_flags       = FS_REQUIRES_DEV,
1209 };
1210
1211 static int __init init_ext2_fs(void)
1212 {
1213         int err = init_ext2_xattr();
1214         if (err)
1215                 return err;
1216         err = init_inodecache();
1217         if (err)
1218                 goto out1;
1219         err = register_filesystem(&ext2_fs_type);
1220         if (err)
1221                 goto out;
1222         return 0;
1223 out:
1224         destroy_inodecache();
1225 out1:
1226         exit_ext2_xattr();
1227         return err;
1228 }
1229
1230 static void __exit exit_ext2_fs(void)
1231 {
1232         unregister_filesystem(&ext2_fs_type);
1233         destroy_inodecache();
1234         exit_ext2_xattr();
1235 }
1236
1237 module_init(init_ext2_fs)
1238 module_exit(exit_ext2_fs)