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 dentry * dentry, 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                                                 SLAB_MEM_SPREAD),
 180                                              init_once, NULL);
 181         if (ext2_inode_cachep == NULL)
 182                 return -ENOMEM;
 183         return 0;
 184 }
 185
 186 static void destroy_inodecache(void)
 187 {
 188         if (kmem_cache_destroy(ext2_inode_cachep))
 189                 printk(KERN_INFO "ext2_inode_cache: not all structures were freed\n");
 190 }
 191
 192 static void ext2_clear_inode(struct inode *inode)
 193 {
 194 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 195         struct ext2_inode_info *ei = EXT2_I(inode);
 196
 197         if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
 198                 posix_acl_release(ei->i_acl);
 199                 ei->i_acl = EXT2_ACL_NOT_CACHED;
 200         }
 201         if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
 202                 posix_acl_release(ei->i_default_acl);
 203                 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 204         }
 205 #endif
 206 }
 207
 208 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
 209 {
 210         struct ext2_sb_info *sbi = EXT2_SB(vfs->mnt_sb);
 211
 212         if (sbi->s_mount_opt & EXT2_MOUNT_GRPID)
 213                 seq_puts(seq, ",grpid");
 214
 215 #if defined(CONFIG_QUOTA)
 216         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
 217                 seq_puts(seq, ",usrquota");
 218
 219         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
 220                 seq_puts(seq, ",grpquota");
 221 #endif
 222
 223 #if defined(CONFIG_EXT2_FS_XIP)
 224         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
 225                 seq_puts(seq, ",xip");
 226 #endif
 227
 228         return 0;
 229 }
 230
 231 #ifdef CONFIG_QUOTA
 232 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
 233 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
 234 #endif
 235
 236 static struct super_operations ext2_sops = {
 237         .alloc_inode    = ext2_alloc_inode,
 238         .destroy_inode  = ext2_destroy_inode,
 239         .read_inode     = ext2_read_inode,
 240         .write_inode    = ext2_write_inode,
 241         .put_inode      = ext2_put_inode,
 242         .delete_inode   = ext2_delete_inode,
 243         .put_super      = ext2_put_super,
 244         .write_super    = ext2_write_super,
 245         .statfs         = ext2_statfs,
 246         .remount_fs     = ext2_remount,
 247         .clear_inode    = ext2_clear_inode,
 248         .show_options   = ext2_show_options,
 249 #ifdef CONFIG_QUOTA
 250         .quota_read     = ext2_quota_read,
 251         .quota_write    = ext2_quota_write,
 252 #endif
 253 };
 254
 255 /* Yes, most of these are left as NULL!!
 256  * A NULL value implies the default, which works with ext2-like file
 257  * systems, but can be improved upon.
 258  * Currently only get_parent is required.
 259  */
 260 static struct export_operations ext2_export_ops = {
 261         .get_parent = ext2_get_parent,
 262 };
 263
 264 static unsigned long get_sb_block(void **data)
 265 {
 266         unsigned long   sb_block;
 267         char            *options = (char *) *data;
 268
 269         if (!options || strncmp(options, "sb=", 3) != 0)
 270                 return 1;       /* Default location */
 271         options += 3;
 272         sb_block = simple_strtoul(options, &options, 0);
 273         if (*options && *options != ',') {
 274                 printk("EXT2-fs: Invalid sb specification: %s\n",
 275                        (char *) *data);
 276                 return 1;
 277         }
 278         if (*options == ',')
 279                 options++;
 280         *data = (void *) options;
 281         return sb_block;
 282 }
 283
 284 enum {
 285         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
 286         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
 287         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
 288         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
 289         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
 290         Opt_usrquota, Opt_grpquota
 291 };
 292
 293 static match_table_t tokens = {
 294         {Opt_bsd_df, "bsddf"},
 295         {Opt_minix_df, "minixdf"},
 296         {Opt_grpid, "grpid"},
 297         {Opt_grpid, "bsdgroups"},
 298         {Opt_nogrpid, "nogrpid"},
 299         {Opt_nogrpid, "sysvgroups"},
 300         {Opt_resgid, "resgid=%u"},
 301         {Opt_resuid, "resuid=%u"},
 302         {Opt_sb, "sb=%u"},
 303         {Opt_err_cont, "errors=continue"},
 304         {Opt_err_panic, "errors=panic"},
 305         {Opt_err_ro, "errors=remount-ro"},
 306         {Opt_nouid32, "nouid32"},
 307         {Opt_nocheck, "check=none"},
 308         {Opt_nocheck, "nocheck"},
 309         {Opt_debug, "debug"},
 310         {Opt_oldalloc, "oldalloc"},
 311         {Opt_orlov, "orlov"},
 312         {Opt_nobh, "nobh"},
 313         {Opt_user_xattr, "user_xattr"},
 314         {Opt_nouser_xattr, "nouser_xattr"},
 315         {Opt_acl, "acl"},
 316         {Opt_noacl, "noacl"},
 317         {Opt_xip, "xip"},
 318         {Opt_grpquota, "grpquota"},
 319         {Opt_ignore, "noquota"},
 320         {Opt_quota, "quota"},
 321         {Opt_usrquota, "usrquota"},
 322         {Opt_err, NULL}
 323 };
 324
 325 static int parse_options (char * options,
 326                           struct ext2_sb_info *sbi)
 327 {
 328         char * p;
 329         substring_t args[MAX_OPT_ARGS];
 330         unsigned long kind = EXT2_MOUNT_ERRORS_CONT;
 331         int option;
 332
 333         if (!options)
 334                 return 1;
 335
 336         while ((p = strsep (&options, ",")) != NULL) {
 337                 int token;
 338                 if (!*p)
 339                         continue;
 340
 341                 token = match_token(p, tokens, args);
 342                 switch (token) {
 343                 case Opt_bsd_df:
 344                         clear_opt (sbi->s_mount_opt, MINIX_DF);
 345                         break;
 346                 case Opt_minix_df:
 347                         set_opt (sbi->s_mount_opt, MINIX_DF);
 348                         break;
 349                 case Opt_grpid:
 350                         set_opt (sbi->s_mount_opt, GRPID);
 351                         break;
 352                 case Opt_nogrpid:
 353                         clear_opt (sbi->s_mount_opt, GRPID);
 354                         break;
 355                 case Opt_resuid:
 356                         if (match_int(&args[0], &option))
 357                                 return 0;
 358                         sbi->s_resuid = option;
 359                         break;
 360                 case Opt_resgid:
 361                         if (match_int(&args[0], &option))
 362                                 return 0;
 363                         sbi->s_resgid = option;
 364                         break;
 365                 case Opt_sb:
 366                         /* handled by get_sb_block() instead of here */
 367                         /* *sb_block = match_int(&args[0]); */
 368                         break;
 369                 case Opt_err_panic:
 370                         kind = EXT2_MOUNT_ERRORS_PANIC;
 371                         break;
 372                 case Opt_err_ro:
 373                         kind = EXT2_MOUNT_ERRORS_RO;
 374                         break;
 375                 case Opt_err_cont:
 376                         kind = EXT2_MOUNT_ERRORS_CONT;
 377                         break;
 378                 case Opt_nouid32:
 379                         set_opt (sbi->s_mount_opt, NO_UID32);
 380                         break;
 381                 case Opt_nocheck:
 382                         clear_opt (sbi->s_mount_opt, CHECK);
 383                         break;
 384                 case Opt_debug:
 385                         set_opt (sbi->s_mount_opt, DEBUG);
 386                         break;
 387                 case Opt_oldalloc:
 388                         set_opt (sbi->s_mount_opt, OLDALLOC);
 389                         break;
 390                 case Opt_orlov:
 391                         clear_opt (sbi->s_mount_opt, OLDALLOC);
 392                         break;
 393                 case Opt_nobh:
 394                         set_opt (sbi->s_mount_opt, NOBH);
 395                         break;
 396 #ifdef CONFIG_EXT2_FS_XATTR
 397                 case Opt_user_xattr:
 398                         set_opt (sbi->s_mount_opt, XATTR_USER);
 399                         break;
 400                 case Opt_nouser_xattr:
 401                         clear_opt (sbi->s_mount_opt, XATTR_USER);
 402                         break;
 403 #else
 404                 case Opt_user_xattr:
 405                 case Opt_nouser_xattr:
 406                         printk("EXT2 (no)user_xattr options not supported\n");
 407                         break;
 408 #endif
 409 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 410                 case Opt_acl:
 411                         set_opt(sbi->s_mount_opt, POSIX_ACL);
 412                         break;
 413                 case Opt_noacl:
 414                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
 415                         break;
 416 #else
 417                 case Opt_acl:
 418                 case Opt_noacl:
 419                         printk("EXT2 (no)acl options not supported\n");
 420                         break;
 421 #endif
 422                 case Opt_xip:
 423 #ifdef CONFIG_EXT2_FS_XIP
 424                         set_opt (sbi->s_mount_opt, XIP);
 425 #else
 426                         printk("EXT2 xip option not supported\n");
 427 #endif
 428                         break;
 429
 430 #if defined(CONFIG_QUOTA)
 431                 case Opt_quota:
 432                 case Opt_usrquota:
 433                         set_opt(sbi->s_mount_opt, USRQUOTA);
 434                         break;
 435
 436                 case Opt_grpquota:
 437                         set_opt(sbi->s_mount_opt, GRPQUOTA);
 438                         break;
 439 #else
 440                 case Opt_quota:
 441                 case Opt_usrquota:
 442                 case Opt_grpquota:
 443                         printk(KERN_ERR
 444                                 "EXT2-fs: quota operations not supported.\n");
 445
 446                         break;
 447 #endif
 448
 449                 case Opt_ignore:
 450                         break;
 451                 default:
 452                         return 0;
 453                 }
 454         }
 455         sbi->s_mount_opt |= kind;
 456         return 1;
 457 }
 458
 459 static int ext2_setup_super (struct super_block * sb,
 460                               struct ext2_super_block * es,
 461                               int read_only)
 462 {
 463         int res = 0;
 464         struct ext2_sb_info *sbi = EXT2_SB(sb);
 465
 466         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 467                 printk ("EXT2-fs warning: revision level too high, "
 468                         "forcing read-only mode\n");
 469                 res = MS_RDONLY;
 470         }
 471         if (read_only)
 472                 return res;
 473         if (!(sbi->s_mount_state & EXT2_VALID_FS))
 474                 printk ("EXT2-fs warning: mounting unchecked fs, "
 475                         "running e2fsck is recommended\n");
 476         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 477                 printk ("EXT2-fs warning: mounting fs with errors, "
 478                         "running e2fsck is recommended\n");
 479         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 480                  le16_to_cpu(es->s_mnt_count) >=
 481                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 482                 printk ("EXT2-fs warning: maximal mount count reached, "
 483                         "running e2fsck is recommended\n");
 484         else if (le32_to_cpu(es->s_checkinterval) &&
 485                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 486                 printk ("EXT2-fs warning: checktime reached, "
 487                         "running e2fsck is recommended\n");
 488         if (!le16_to_cpu(es->s_max_mnt_count))
 489                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 490         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
 491         ext2_write_super(sb);
 492         if (test_opt (sb, DEBUG))
 493                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
 494                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
 495                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 496                         sbi->s_frag_size,
 497                         sbi->s_groups_count,
 498                         EXT2_BLOCKS_PER_GROUP(sb),
 499                         EXT2_INODES_PER_GROUP(sb),
 500                         sbi->s_mount_opt);
 501         return res;
 502 }
 503
 504 static int ext2_check_descriptors (struct super_block * sb)
 505 {
 506         int i;
 507         int desc_block = 0;
 508         struct ext2_sb_info *sbi = EXT2_SB(sb);
 509         unsigned long block = le32_to_cpu(sbi->s_es->s_first_data_block);
 510         struct ext2_group_desc * gdp = NULL;
 511
 512         ext2_debug ("Checking group descriptors");
 513
 514         for (i = 0; i < sbi->s_groups_count; i++)
 515         {
 516                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
 517                         gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
 518                 if (le32_to_cpu(gdp->bg_block_bitmap) < block ||
 519                     le32_to_cpu(gdp->bg_block_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 520                 {
 521                         ext2_error (sb, "ext2_check_descriptors",
 522                                     "Block bitmap for group %d"
 523                                     " not in group (block %lu)!",
 524                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 525                         return 0;
 526                 }
 527                 if (le32_to_cpu(gdp->bg_inode_bitmap) < block ||
 528                     le32_to_cpu(gdp->bg_inode_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 529                 {
 530                         ext2_error (sb, "ext2_check_descriptors",
 531                                     "Inode bitmap for group %d"
 532                                     " not in group (block %lu)!",
 533                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 534                         return 0;
 535                 }
 536                 if (le32_to_cpu(gdp->bg_inode_table) < block ||
 537                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >=
 538                     block + EXT2_BLOCKS_PER_GROUP(sb))
 539                 {
 540                         ext2_error (sb, "ext2_check_descriptors",
 541                                     "Inode table for group %d"
 542                                     " not in group (block %lu)!",
 543                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 544                         return 0;
 545                 }
 546                 block += EXT2_BLOCKS_PER_GROUP(sb);
 547                 gdp++;
 548         }
 549         return 1;
 550 }
 551
 552 #define log2(n) ffz(~(n))
 553
 554 /*
 555  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 556  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 557  * We need to be 1 filesystem block less than the 2^32 sector limit.
 558  */
 559 static loff_t ext2_max_size(int bits)
 560 {
 561         loff_t res = EXT2_NDIR_BLOCKS;
 562         /* This constant is calculated to be the largest file size for a
 563          * dense, 4k-blocksize file such that the total number of
 564          * sectors in the file, including data and all indirect blocks,
 565          * does not exceed 2^32. */
 566         const loff_t upper_limit = 0x1ff7fffd000LL;
 567
 568         res += 1LL << (bits-2);
 569         res += 1LL << (2*(bits-2));
 570         res += 1LL << (3*(bits-2));
 571         res <<= bits;
 572         if (res > upper_limit)
 573                 res = upper_limit;
 574         return res;
 575 }
 576
 577 static unsigned long descriptor_loc(struct super_block *sb,
 578                                     unsigned long logic_sb_block,
 579                                     int nr)
 580 {
 581         struct ext2_sb_info *sbi = EXT2_SB(sb);
 582         unsigned long bg, first_data_block, first_meta_bg;
 583         int has_super = 0;
 584
 585         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 586         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 587
 588         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 589             nr < first_meta_bg)
 590                 return (logic_sb_block + nr + 1);
 591         bg = sbi->s_desc_per_block * nr;
 592         if (ext2_bg_has_super(sb, bg))
 593                 has_super = 1;
 594         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
 595 }
 596
 597 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 598 {
 599         struct buffer_head * bh;
 600         struct ext2_sb_info * sbi;
 601         struct ext2_super_block * es;
 602         struct inode *root;
 603         unsigned long block;
 604         unsigned long sb_block = get_sb_block(&data);
 605         unsigned long logic_sb_block;
 606         unsigned long offset = 0;
 607         unsigned long def_mount_opts;
 608         int blocksize = BLOCK_SIZE;
 609         int db_count;
 610         int i, j;
 611         __le32 features;
 612
 613         sbi = kmalloc(sizeof(*sbi), GFP_KERNEL);
 614         if (!sbi)
 615                 return -ENOMEM;
 616         sb->s_fs_info = sbi;
 617         memset(sbi, 0, sizeof(*sbi));
 618
 619         /*
 620          * See what the current blocksize for the device is, and
 621          * use that as the blocksize.  Otherwise (or if the blocksize
 622          * is smaller than the default) use the default.
 623          * This is important for devices that have a hardware
 624          * sectorsize that is larger than the default.
 625          */
 626         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 627         if (!blocksize) {
 628                 printk ("EXT2-fs: unable to set blocksize\n");
 629                 goto failed_sbi;
 630         }
 631
 632         /*
 633          * If the superblock doesn't start on a hardware sector boundary,
 634          * calculate the offset.
 635          */
 636         if (blocksize != BLOCK_SIZE) {
 637                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 638                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 639         } else {
 640                 logic_sb_block = sb_block;
 641         }
 642
 643         if (!(bh = sb_bread(sb, logic_sb_block))) {
 644                 printk ("EXT2-fs: unable to read superblock\n");
 645                 goto failed_sbi;
 646         }
 647         /*
 648          * Note: s_es must be initialized as soon as possible because
 649          *       some ext2 macro-instructions depend on its value
 650          */
 651         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 652         sbi->s_es = es;
 653         sb->s_magic = le16_to_cpu(es->s_magic);
 654
 655         if (sb->s_magic != EXT2_SUPER_MAGIC)
 656                 goto cantfind_ext2;
 657
 658         /* Set defaults before we parse the mount options */
 659         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 660         if (def_mount_opts & EXT2_DEFM_DEBUG)
 661                 set_opt(sbi->s_mount_opt, DEBUG);
 662         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 663                 set_opt(sbi->s_mount_opt, GRPID);
 664         if (def_mount_opts & EXT2_DEFM_UID16)
 665                 set_opt(sbi->s_mount_opt, NO_UID32);
 666         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 667                 set_opt(sbi->s_mount_opt, XATTR_USER);
 668         if (def_mount_opts & EXT2_DEFM_ACL)
 669                 set_opt(sbi->s_mount_opt, POSIX_ACL);
 670
 671         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 672                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 673         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
 674                 set_opt(sbi->s_mount_opt, ERRORS_RO);
 675
 676         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
 677         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
 678
 679         if (!parse_options ((char *) data, sbi))
 680                 goto failed_mount;
 681
 682         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 683                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 684                  MS_POSIXACL : 0);
 685
 686         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
 687                                     EXT2_MOUNT_XIP if not */
 688
 689         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 690             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 691              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 692              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 693                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
 694                        "running e2fsck is recommended\n");
 695         /*
 696          * Check feature flags regardless of the revision level, since we
 697          * previously didn't change the revision level when setting the flags,
 698          * so there is a chance incompat flags are set on a rev 0 filesystem.
 699          */
 700         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 701         if (features) {
 702                 printk("EXT2-fs: %s: couldn't mount because of "
 703                        "unsupported optional features (%x).\n",
 704                        sb->s_id, le32_to_cpu(features));
 705                 goto failed_mount;
 706         }
 707         if (!(sb->s_flags & MS_RDONLY) &&
 708             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 709                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
 710                        "unsupported optional features (%x).\n",
 711                        sb->s_id, le32_to_cpu(features));
 712                 goto failed_mount;
 713         }
 714
 715         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 716
 717         if ((ext2_use_xip(sb)) && ((blocksize != PAGE_SIZE) ||
 718                                   (sb->s_blocksize != blocksize))) {
 719                 if (!silent)
 720                         printk("XIP: Unsupported blocksize\n");
 721                 goto failed_mount;
 722         }
 723
 724         /* If the blocksize doesn't match, re-read the thing.. */
 725         if (sb->s_blocksize != blocksize) {
 726                 brelse(bh);
 727
 728                 if (!sb_set_blocksize(sb, blocksize)) {
 729                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
 730                         goto failed_sbi;
 731                 }
 732
 733                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 734                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 735                 bh = sb_bread(sb, logic_sb_block);
 736                 if(!bh) {
 737                         printk("EXT2-fs: Couldn't read superblock on "
 738                                "2nd try.\n");
 739                         goto failed_sbi;
 740                 }
 741                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 742                 sbi->s_es = es;
 743                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 744                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
 745                         goto failed_mount;
 746                 }
 747         }
 748
 749         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 750
 751         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 752                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 753                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 754         } else {
 755                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 756                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 757                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 758                     (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
 759                     (sbi->s_inode_size > blocksize)) {
 760                         printk ("EXT2-fs: unsupported inode size: %d\n",
 761                                 sbi->s_inode_size);
 762                         goto failed_mount;
 763                 }
 764         }
 765
 766         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 767                                    le32_to_cpu(es->s_log_frag_size);
 768         if (sbi->s_frag_size == 0)
 769                 goto cantfind_ext2;
 770         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
 771
 772         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 773         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 774         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 775
 776         if (EXT2_INODE_SIZE(sb) == 0)
 777                 goto cantfind_ext2;
 778         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
 779         if (sbi->s_inodes_per_block == 0)
 780                 goto cantfind_ext2;
 781         sbi->s_itb_per_group = sbi->s_inodes_per_group /
 782                                         sbi->s_inodes_per_block;
 783         sbi->s_desc_per_block = sb->s_blocksize /
 784                                         sizeof (struct ext2_group_desc);
 785         sbi->s_sbh = bh;
 786         sbi->s_mount_state = le16_to_cpu(es->s_state);
 787         sbi->s_addr_per_block_bits =
 788                 log2 (EXT2_ADDR_PER_BLOCK(sb));
 789         sbi->s_desc_per_block_bits =
 790                 log2 (EXT2_DESC_PER_BLOCK(sb));
 791
 792         if (sb->s_magic != EXT2_SUPER_MAGIC)
 793                 goto cantfind_ext2;
 794
 795         if (sb->s_blocksize != bh->b_size) {
 796                 if (!silent)
 797                         printk ("VFS: Unsupported blocksize on dev "
 798                                 "%s.\n", sb->s_id);
 799                 goto failed_mount;
 800         }
 801
 802         if (sb->s_blocksize != sbi->s_frag_size) {
 803                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
 804                         sbi->s_frag_size, sb->s_blocksize);
 805                 goto failed_mount;
 806         }
 807
 808         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
 809                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
 810                         sbi->s_blocks_per_group);
 811                 goto failed_mount;
 812         }
 813         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 814                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
 815                         sbi->s_frags_per_group);
 816                 goto failed_mount;
 817         }
 818         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
 819                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
 820                         sbi->s_inodes_per_group);
 821                 goto failed_mount;
 822         }
 823
 824         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
 825                 goto cantfind_ext2;
 826         sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) -
 827                                         le32_to_cpu(es->s_first_data_block) +
 828                                        EXT2_BLOCKS_PER_GROUP(sb) - 1) /
 829                                        EXT2_BLOCKS_PER_GROUP(sb);
 830         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
 831                    EXT2_DESC_PER_BLOCK(sb);
 832         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
 833         if (sbi->s_group_desc == NULL) {
 834                 printk ("EXT2-fs: not enough memory\n");
 835                 goto failed_mount;
 836         }
 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         percpu_counter_init(&sbi->s_freeblocks_counter,
 865                                 ext2_count_free_blocks(sb));
 866         percpu_counter_init(&sbi->s_freeinodes_counter,
 867                                 ext2_count_free_inodes(sb));
 868         percpu_counter_init(&sbi->s_dirs_counter,
 869                                 ext2_count_dirs(sb));
 870         /*
 871          * set up enough so that it can read an inode
 872          */
 873         sb->s_op = &ext2_sops;
 874         sb->s_export_op = &ext2_export_ops;
 875         sb->s_xattr = ext2_xattr_handlers;
 876         root = iget(sb, EXT2_ROOT_INO);
 877         sb->s_root = d_alloc_root(root);
 878         if (!sb->s_root) {
 879                 iput(root);
 880                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
 881                 goto failed_mount3;
 882         }
 883         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
 884                 dput(sb->s_root);
 885                 sb->s_root = NULL;
 886                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
 887                 goto failed_mount3;
 888         }
 889         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 890                 ext2_warning(sb, __FUNCTION__,
 891                         "mounting ext3 filesystem as ext2");
 892         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
 893         return 0;
 894
 895 cantfind_ext2:
 896         if (!silent)
 897                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
 898                        sb->s_id);
 899         goto failed_mount;
 900 failed_mount3:
 901         percpu_counter_destroy(&sbi->s_freeblocks_counter);
 902         percpu_counter_destroy(&sbi->s_freeinodes_counter);
 903         percpu_counter_destroy(&sbi->s_dirs_counter);
 904 failed_mount2:
 905         for (i = 0; i < db_count; i++)
 906                 brelse(sbi->s_group_desc[i]);
 907 failed_mount_group_desc:
 908         kfree(sbi->s_group_desc);
 909         kfree(sbi->s_debts);
 910 failed_mount:
 911         brelse(bh);
 912 failed_sbi:
 913         sb->s_fs_info = NULL;
 914         kfree(sbi);
 915         return -EINVAL;
 916 }
 917
 918 static void ext2_commit_super (struct super_block * sb,
 919                                struct ext2_super_block * es)
 920 {
 921         es->s_wtime = cpu_to_le32(get_seconds());
 922         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 923         sb->s_dirt = 0;
 924 }
 925
 926 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
 927 {
 928         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 929         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 930         es->s_wtime = cpu_to_le32(get_seconds());
 931         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 932         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
 933         sb->s_dirt = 0;
 934 }
 935
 936 /*
 937  * In the second extended file system, it is not necessary to
 938  * write the super block since we use a mapping of the
 939  * disk super block in a buffer.
 940  *
 941  * However, this function is still used to set the fs valid
 942  * flags to 0.  We need to set this flag to 0 since the fs
 943  * may have been checked while mounted and e2fsck may have
 944  * set s_state to EXT2_VALID_FS after some corrections.
 945  */
 946
 947 void ext2_write_super (struct super_block * sb)
 948 {
 949         struct ext2_super_block * es;
 950         lock_kernel();
 951         if (!(sb->s_flags & MS_RDONLY)) {
 952                 es = EXT2_SB(sb)->s_es;
 953
 954                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
 955                         ext2_debug ("setting valid to 0\n");
 956                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
 957                                                   ~EXT2_VALID_FS);
 958                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 959                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 960                         es->s_mtime = cpu_to_le32(get_seconds());
 961                         ext2_sync_super(sb, es);
 962                 } else
 963                         ext2_commit_super (sb, es);
 964         }
 965         sb->s_dirt = 0;
 966         unlock_kernel();
 967 }
 968
 969 static int ext2_remount (struct super_block * sb, int * flags, char * data)
 970 {
 971         struct ext2_sb_info * sbi = EXT2_SB(sb);
 972         struct ext2_super_block * es;
 973         unsigned long old_mount_opt = sbi->s_mount_opt;
 974         struct ext2_mount_options old_opts;
 975         unsigned long old_sb_flags;
 976         int err;
 977
 978         /* Store the old options */
 979         old_sb_flags = sb->s_flags;
 980         old_opts.s_mount_opt = sbi->s_mount_opt;
 981         old_opts.s_resuid = sbi->s_resuid;
 982         old_opts.s_resgid = sbi->s_resgid;
 983
 984         /*
 985          * Allow the "check" option to be passed as a remount option.
 986          */
 987         if (!parse_options (data, sbi)) {
 988                 err = -EINVAL;
 989                 goto restore_opts;
 990         }
 991
 992         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 993                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
 994
 995         es = sbi->s_es;
 996         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
 997             (old_mount_opt & EXT2_MOUNT_XIP)) &&
 998             invalidate_inodes(sb))
 999                 ext2_warning(sb, __FUNCTION__, "busy inodes while remounting "\
1000                              "xip remain in cache (no functional problem)");
1001         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1002                 return 0;
1003         if (*flags & MS_RDONLY) {
1004                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1005                     !(sbi->s_mount_state & EXT2_VALID_FS))
1006                         return 0;
1007                 /*
1008                  * OK, we are remounting a valid rw partition rdonly, so set
1009                  * the rdonly flag and then mark the partition as valid again.
1010                  */
1011                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1012                 es->s_mtime = cpu_to_le32(get_seconds());
1013         } else {
1014                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1015                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1016                 if (ret) {
1017                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
1018                                "unsupported optional features (%x).\n",
1019                                sb->s_id, le32_to_cpu(ret));
1020                         err = -EROFS;
1021                         goto restore_opts;
1022                 }
1023                 /*
1024                  * Mounting a RDONLY partition read-write, so reread and
1025                  * store the current valid flag.  (It may have been changed
1026                  * by e2fsck since we originally mounted the partition.)
1027                  */
1028                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1029                 if (!ext2_setup_super (sb, es, 0))
1030                         sb->s_flags &= ~MS_RDONLY;
1031         }
1032         ext2_sync_super(sb, es);
1033         return 0;
1034 restore_opts:
1035         sbi->s_mount_opt = old_opts.s_mount_opt;
1036         sbi->s_resuid = old_opts.s_resuid;
1037         sbi->s_resgid = old_opts.s_resgid;
1038         sb->s_flags = old_sb_flags;
1039         return err;
1040 }
1041
1042 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1043 {
1044         struct super_block *sb = dentry->d_sb;
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 int ext2_get_sb(struct file_system_type *fs_type,
1093         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1094 {
1095         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super, mnt);
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)