fs/ext2/super.c

   1 /*
   2  *  linux/fs/ext2/super.c
   3  *
   4  * Copyright (C) 1992, 1993, 1994, 1995
   5  * Remy Card (card@masi.ibp.fr)
   6  * Laboratoire MASI - Institut Blaise Pascal
   7  * Universite Pierre et Marie Curie (Paris VI)
   8  *
   9  *  from
  10  *
  11  *  linux/fs/minix/inode.c
  12  *
  13  *  Copyright (C) 1991, 1992  Linus Torvalds
  14  *
  15  *  Big-endian to little-endian byte-swapping/bitmaps by
  16  *        David S. Miller (davem@caip.rutgers.edu), 1995
  17  */
  18
  19 #include <linux/config.h>
  20 #include <linux/module.h>
  21 #include <linux/string.h>
  22 #include <linux/slab.h>
  23 #include <linux/init.h>
  24 #include <linux/blkdev.h>
  25 #include <linux/parser.h>
  26 #include <linux/random.h>
  27 #include <linux/buffer_head.h>
  28 #include <linux/smp_lock.h>
  29 #include <linux/vfs.h>
  30 #include <asm/uaccess.h>
  31 #include "ext2.h"
  32 #include "xattr.h"
  33 #include "acl.h"
  34
  35 static void ext2_sync_super(struct super_block *sb,
  36                             struct ext2_super_block *es);
  37 static int ext2_remount (struct super_block * sb, int * flags, char * data);
  38 static int ext2_statfs (struct super_block * sb, struct kstatfs * buf);
  39
  40 void ext2_error (struct super_block * sb, const char * function,
  41                  const char * fmt, ...)
  42 {
  43         va_list args;
  44         struct ext2_sb_info *sbi = EXT2_SB(sb);
  45         struct ext2_super_block *es = sbi->s_es;
  46
  47         if (!(sb->s_flags & MS_RDONLY)) {
  48                 sbi->s_mount_state |= EXT2_ERROR_FS;
  49                 es->s_state =
  50                         cpu_to_le16(le16_to_cpu(es->s_state) | EXT2_ERROR_FS);
  51                 ext2_sync_super(sb, es);
  52         }
  53
  54         va_start(args, fmt);
  55         printk(KERN_CRIT "EXT2-fs error (device %s): %s: ",sb->s_id, function);
  56         vprintk(fmt, args);
  57         printk("\n");
  58         va_end(args);
  59
  60         if (test_opt(sb, ERRORS_PANIC))
  61                 panic("EXT2-fs panic from previous error\n");
  62         if (test_opt(sb, ERRORS_RO)) {
  63                 printk("Remounting filesystem read-only\n");
  64                 sb->s_flags |= MS_RDONLY;
  65         }
  66 }
  67
  68 void ext2_warning (struct super_block * sb, const char * function,
  69                    const char * fmt, ...)
  70 {
  71         va_list args;
  72
  73         va_start(args, fmt);
  74         printk(KERN_WARNING "EXT2-fs warning (device %s): %s: ",
  75                sb->s_id, function);
  76         vprintk(fmt, args);
  77         printk("\n");
  78         va_end(args);
  79 }
  80
  81 void ext2_update_dynamic_rev(struct super_block *sb)
  82 {
  83         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
  84
  85         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
  86                 return;
  87
  88         ext2_warning(sb, __FUNCTION__,
  89                      "updating to rev %d because of new feature flag, "
  90                      "running e2fsck is recommended",
  91                      EXT2_DYNAMIC_REV);
  92
  93         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
  94         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
  95         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
  96         /* leave es->s_feature_*compat flags alone */
  97         /* es->s_uuid will be set by e2fsck if empty */
  98
  99         /*
 100          * The rest of the superblock fields should be zero, and if not it
 101          * means they are likely already in use, so leave them alone.  We
 102          * can leave it up to e2fsck to clean up any inconsistencies there.
 103          */
 104 }
 105
 106 static void ext2_put_super (struct super_block * sb)
 107 {
 108         int db_count;
 109         int i;
 110         struct ext2_sb_info *sbi = EXT2_SB(sb);
 111
 112         ext2_xattr_put_super(sb);
 113         if (!(sb->s_flags & MS_RDONLY)) {
 114                 struct ext2_super_block *es = sbi->s_es;
 115
 116                 es->s_state = cpu_to_le16(sbi->s_mount_state);
 117                 ext2_sync_super(sb, es);
 118         }
 119         db_count = sbi->s_gdb_count;
 120         for (i = 0; i < db_count; i++)
 121                 if (sbi->s_group_desc[i])
 122                         brelse (sbi->s_group_desc[i]);
 123         kfree(sbi->s_group_desc);
 124         kfree(sbi->s_debts);
 125         brelse (sbi->s_sbh);
 126         sb->s_fs_info = NULL;
 127         kfree(sbi);
 128
 129         return;
 130 }
 131
 132 static kmem_cache_t * ext2_inode_cachep;
 133
 134 static struct inode *ext2_alloc_inode(struct super_block *sb)
 135 {
 136         struct ext2_inode_info *ei;
 137         ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, SLAB_KERNEL);
 138         if (!ei)
 139                 return NULL;
 140 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 141         ei->i_acl = EXT2_ACL_NOT_CACHED;
 142         ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 143 #endif
 144         ei->vfs_inode.i_version = 1;
 145         return &ei->vfs_inode;
 146 }
 147
 148 static void ext2_destroy_inode(struct inode *inode)
 149 {
 150         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
 151 }
 152
 153 static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
 154 {
 155         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
 156
 157         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 158             SLAB_CTOR_CONSTRUCTOR) {
 159                 rwlock_init(&ei->i_meta_lock);
 160 #ifdef CONFIG_EXT2_FS_XATTR
 161                 init_rwsem(&ei->xattr_sem);
 162 #endif
 163                 inode_init_once(&ei->vfs_inode);
 164         }
 165 }
 166
 167 static int init_inodecache(void)
 168 {
 169         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
 170                                              sizeof(struct ext2_inode_info),
 171                                              0, SLAB_RECLAIM_ACCOUNT,
 172                                              init_once, NULL);
 173         if (ext2_inode_cachep == NULL)
 174                 return -ENOMEM;
 175         return 0;
 176 }
 177
 178 static void destroy_inodecache(void)
 179 {
 180         if (kmem_cache_destroy(ext2_inode_cachep))
 181                 printk(KERN_INFO "ext2_inode_cache: not all structures were freed\n");
 182 }
 183
 184 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 185
 186 static void ext2_clear_inode(struct inode *inode)
 187 {
 188         struct ext2_inode_info *ei = EXT2_I(inode);
 189
 190         if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
 191                 posix_acl_release(ei->i_acl);
 192                 ei->i_acl = EXT2_ACL_NOT_CACHED;
 193         }
 194         if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
 195                 posix_acl_release(ei->i_default_acl);
 196                 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 197         }
 198 }
 199
 200 #else
 201 # define ext2_clear_inode NULL
 202 #endif
 203
 204 static struct super_operations ext2_sops = {
 205         .alloc_inode    = ext2_alloc_inode,
 206         .destroy_inode  = ext2_destroy_inode,
 207         .read_inode     = ext2_read_inode,
 208         .write_inode    = ext2_write_inode,
 209         .put_inode      = ext2_put_inode,
 210         .delete_inode   = ext2_delete_inode,
 211         .put_super      = ext2_put_super,
 212         .write_super    = ext2_write_super,
 213         .statfs         = ext2_statfs,
 214         .remount_fs     = ext2_remount,
 215         .clear_inode    = ext2_clear_inode,
 216 };
 217
 218 /* Yes, most of these are left as NULL!!
 219  * A NULL value implies the default, which works with ext2-like file
 220  * systems, but can be improved upon.
 221  * Currently only get_parent is required.
 222  */
 223 struct dentry *ext2_get_parent(struct dentry *child);
 224 static struct export_operations ext2_export_ops = {
 225         .get_parent = ext2_get_parent,
 226 };
 227
 228 static unsigned long get_sb_block(void **data)
 229 {
 230         unsigned long   sb_block;
 231         char            *options = (char *) *data;
 232
 233         if (!options || strncmp(options, "sb=", 3) != 0)
 234                 return 1;       /* Default location */
 235         options += 3;
 236         sb_block = simple_strtoul(options, &options, 0);
 237         if (*options && *options != ',') {
 238                 printk("EXT2-fs: Invalid sb specification: %s\n",
 239                        (char *) *data);
 240                 return 1;
 241         }
 242         if (*options == ',')
 243                 options++;
 244         *data = (void *) options;
 245         return sb_block;
 246 }
 247
 248 enum {
 249         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
 250         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
 251         Opt_nouid32, Opt_check, Opt_nocheck, Opt_debug, Opt_oldalloc, Opt_orlov, Opt_nobh,
 252         Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
 253         Opt_ignore, Opt_err,
 254 };
 255
 256 static match_table_t tokens = {
 257         {Opt_bsd_df, "bsddf"},
 258         {Opt_minix_df, "minixdf"},
 259         {Opt_grpid, "grpid"},
 260         {Opt_grpid, "bsdgroups"},
 261         {Opt_nogrpid, "nogrpid"},
 262         {Opt_nogrpid, "sysvgroups"},
 263         {Opt_resgid, "resgid=%u"},
 264         {Opt_resuid, "resuid=%u"},
 265         {Opt_sb, "sb=%u"},
 266         {Opt_err_cont, "errors=continue"},
 267         {Opt_err_panic, "errors=panic"},
 268         {Opt_err_ro, "errors=remount-ro"},
 269         {Opt_nouid32, "nouid32"},
 270         {Opt_nocheck, "check=none"},
 271         {Opt_nocheck, "nocheck"},
 272         {Opt_check, "check"},
 273         {Opt_debug, "debug"},
 274         {Opt_oldalloc, "oldalloc"},
 275         {Opt_orlov, "orlov"},
 276         {Opt_nobh, "nobh"},
 277         {Opt_user_xattr, "user_xattr"},
 278         {Opt_nouser_xattr, "nouser_xattr"},
 279         {Opt_acl, "acl"},
 280         {Opt_noacl, "noacl"},
 281         {Opt_ignore, "grpquota"},
 282         {Opt_ignore, "noquota"},
 283         {Opt_ignore, "quota"},
 284         {Opt_ignore, "usrquota"},
 285         {Opt_err, NULL}
 286 };
 287
 288 static int parse_options (char * options,
 289                           struct ext2_sb_info *sbi)
 290 {
 291         char * p;
 292         substring_t args[MAX_OPT_ARGS];
 293         unsigned long kind = EXT2_MOUNT_ERRORS_CONT;
 294         int option;
 295
 296         if (!options)
 297                 return 1;
 298
 299         while ((p = strsep (&options, ",")) != NULL) {
 300                 int token;
 301                 if (!*p)
 302                         continue;
 303
 304                 token = match_token(p, tokens, args);
 305                 switch (token) {
 306                 case Opt_bsd_df:
 307                         clear_opt (sbi->s_mount_opt, MINIX_DF);
 308                         break;
 309                 case Opt_minix_df:
 310                         set_opt (sbi->s_mount_opt, MINIX_DF);
 311                         break;
 312                 case Opt_grpid:
 313                         set_opt (sbi->s_mount_opt, GRPID);
 314                         break;
 315                 case Opt_nogrpid:
 316                         clear_opt (sbi->s_mount_opt, GRPID);
 317                         break;
 318                 case Opt_resuid:
 319                         if (match_int(&args[0], &option))
 320                                 return 0;
 321                         sbi->s_resuid = option;
 322                         break;
 323                 case Opt_resgid:
 324                         if (match_int(&args[0], &option))
 325                                 return 0;
 326                         sbi->s_resgid = option;
 327                         break;
 328                 case Opt_sb:
 329                         /* handled by get_sb_block() instead of here */
 330                         /* *sb_block = match_int(&args[0]); */
 331                         break;
 332                 case Opt_err_panic:
 333                         kind = EXT2_MOUNT_ERRORS_PANIC;
 334                         break;
 335                 case Opt_err_ro:
 336                         kind = EXT2_MOUNT_ERRORS_RO;
 337                         break;
 338                 case Opt_err_cont:
 339                         kind = EXT2_MOUNT_ERRORS_CONT;
 340                         break;
 341                 case Opt_nouid32:
 342                         set_opt (sbi->s_mount_opt, NO_UID32);
 343                         break;
 344                 case Opt_check:
 345 #ifdef CONFIG_EXT2_CHECK
 346                         set_opt (sbi->s_mount_opt, CHECK);
 347 #else
 348                         printk("EXT2 Check option not supported\n");
 349 #endif
 350                         break;
 351                 case Opt_nocheck:
 352                         clear_opt (sbi->s_mount_opt, CHECK);
 353                         break;
 354                 case Opt_debug:
 355                         set_opt (sbi->s_mount_opt, DEBUG);
 356                         break;
 357                 case Opt_oldalloc:
 358                         set_opt (sbi->s_mount_opt, OLDALLOC);
 359                         break;
 360                 case Opt_orlov:
 361                         clear_opt (sbi->s_mount_opt, OLDALLOC);
 362                         break;
 363                 case Opt_nobh:
 364                         set_opt (sbi->s_mount_opt, NOBH);
 365                         break;
 366 #ifdef CONFIG_EXT2_FS_XATTR
 367                 case Opt_user_xattr:
 368                         set_opt (sbi->s_mount_opt, XATTR_USER);
 369                         break;
 370                 case Opt_nouser_xattr:
 371                         clear_opt (sbi->s_mount_opt, XATTR_USER);
 372                         break;
 373 #else
 374                 case Opt_user_xattr:
 375                 case Opt_nouser_xattr:
 376                         printk("EXT2 (no)user_xattr options not supported\n");
 377                         break;
 378 #endif
 379 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 380                 case Opt_acl:
 381                         set_opt(sbi->s_mount_opt, POSIX_ACL);
 382                         break;
 383                 case Opt_noacl:
 384                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
 385                         break;
 386 #else
 387                 case Opt_acl:
 388                 case Opt_noacl:
 389                         printk("EXT2 (no)acl options not supported\n");
 390                         break;
 391 #endif
 392                 case Opt_ignore:
 393                         break;
 394                 default:
 395                         return 0;
 396                 }
 397         }
 398         sbi->s_mount_opt |= kind;
 399         return 1;
 400 }
 401
 402 static int ext2_setup_super (struct super_block * sb,
 403                               struct ext2_super_block * es,
 404                               int read_only)
 405 {
 406         int res = 0;
 407         struct ext2_sb_info *sbi = EXT2_SB(sb);
 408
 409         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 410                 printk ("EXT2-fs warning: revision level too high, "
 411                         "forcing read-only mode\n");
 412                 res = MS_RDONLY;
 413         }
 414         if (read_only)
 415                 return res;
 416         if (!(sbi->s_mount_state & EXT2_VALID_FS))
 417                 printk ("EXT2-fs warning: mounting unchecked fs, "
 418                         "running e2fsck is recommended\n");
 419         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 420                 printk ("EXT2-fs warning: mounting fs with errors, "
 421                         "running e2fsck is recommended\n");
 422         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 423                  le16_to_cpu(es->s_mnt_count) >=
 424                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 425                 printk ("EXT2-fs warning: maximal mount count reached, "
 426                         "running e2fsck is recommended\n");
 427         else if (le32_to_cpu(es->s_checkinterval) &&
 428                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 429                 printk ("EXT2-fs warning: checktime reached, "
 430                         "running e2fsck is recommended\n");
 431         if (!le16_to_cpu(es->s_max_mnt_count))
 432                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 433         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
 434         ext2_write_super(sb);
 435         if (test_opt (sb, DEBUG))
 436                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
 437                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
 438                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 439                         sbi->s_frag_size,
 440                         sbi->s_groups_count,
 441                         EXT2_BLOCKS_PER_GROUP(sb),
 442                         EXT2_INODES_PER_GROUP(sb),
 443                         sbi->s_mount_opt);
 444 #ifdef CONFIG_EXT2_CHECK
 445         if (test_opt (sb, CHECK)) {
 446                 ext2_check_blocks_bitmap (sb);
 447                 ext2_check_inodes_bitmap (sb);
 448         }
 449 #endif
 450         return res;
 451 }
 452
 453 static int ext2_check_descriptors (struct super_block * sb)
 454 {
 455         int i;
 456         int desc_block = 0;
 457         struct ext2_sb_info *sbi = EXT2_SB(sb);
 458         unsigned long block = le32_to_cpu(sbi->s_es->s_first_data_block);
 459         struct ext2_group_desc * gdp = NULL;
 460
 461         ext2_debug ("Checking group descriptors");
 462
 463         for (i = 0; i < sbi->s_groups_count; i++)
 464         {
 465                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
 466                         gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
 467                 if (le32_to_cpu(gdp->bg_block_bitmap) < block ||
 468                     le32_to_cpu(gdp->bg_block_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 469                 {
 470                         ext2_error (sb, "ext2_check_descriptors",
 471                                     "Block bitmap for group %d"
 472                                     " not in group (block %lu)!",
 473                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 474                         return 0;
 475                 }
 476                 if (le32_to_cpu(gdp->bg_inode_bitmap) < block ||
 477                     le32_to_cpu(gdp->bg_inode_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 478                 {
 479                         ext2_error (sb, "ext2_check_descriptors",
 480                                     "Inode bitmap for group %d"
 481                                     " not in group (block %lu)!",
 482                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 483                         return 0;
 484                 }
 485                 if (le32_to_cpu(gdp->bg_inode_table) < block ||
 486                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >=
 487                     block + EXT2_BLOCKS_PER_GROUP(sb))
 488                 {
 489                         ext2_error (sb, "ext2_check_descriptors",
 490                                     "Inode table for group %d"
 491                                     " not in group (block %lu)!",
 492                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 493                         return 0;
 494                 }
 495                 block += EXT2_BLOCKS_PER_GROUP(sb);
 496                 gdp++;
 497         }
 498         return 1;
 499 }
 500
 501 #define log2(n) ffz(~(n))
 502
 503 /*
 504  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 505  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 506  * We need to be 1 filesystem block less than the 2^32 sector limit.
 507  */
 508 static loff_t ext2_max_size(int bits)
 509 {
 510         loff_t res = EXT2_NDIR_BLOCKS;
 511         res += 1LL << (bits-2);
 512         res += 1LL << (2*(bits-2));
 513         res += 1LL << (3*(bits-2));
 514         res <<= bits;
 515         if (res > (512LL << 32) - (1 << bits))
 516                 res = (512LL << 32) - (1 << bits);
 517         return res;
 518 }
 519
 520 static unsigned long descriptor_loc(struct super_block *sb,
 521                                     unsigned long logic_sb_block,
 522                                     int nr)
 523 {
 524         struct ext2_sb_info *sbi = EXT2_SB(sb);
 525         unsigned long bg, first_data_block, first_meta_bg;
 526         int has_super = 0;
 527
 528         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 529         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 530
 531         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 532             nr < first_meta_bg)
 533                 return (logic_sb_block + nr + 1);
 534         bg = sbi->s_desc_per_block * nr;
 535         if (ext2_bg_has_super(sb, bg))
 536                 has_super = 1;
 537         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
 538 }
 539
 540 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 541 {
 542         struct buffer_head * bh;
 543         struct ext2_sb_info * sbi;
 544         struct ext2_super_block * es;
 545         struct inode *root;
 546         unsigned long block;
 547         unsigned long sb_block = get_sb_block(&data);
 548         unsigned long logic_sb_block;
 549         unsigned long offset = 0;
 550         unsigned long def_mount_opts;
 551         int blocksize = BLOCK_SIZE;
 552         int db_count;
 553         int i, j;
 554         __le32 features;
 555
 556         sbi = kmalloc(sizeof(*sbi), GFP_KERNEL);
 557         if (!sbi)
 558                 return -ENOMEM;
 559         sb->s_fs_info = sbi;
 560         memset(sbi, 0, sizeof(*sbi));
 561
 562         /*
 563          * See what the current blocksize for the device is, and
 564          * use that as the blocksize.  Otherwise (or if the blocksize
 565          * is smaller than the default) use the default.
 566          * This is important for devices that have a hardware
 567          * sectorsize that is larger than the default.
 568          */
 569         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 570         if (!blocksize) {
 571                 printk ("EXT2-fs: unable to set blocksize\n");
 572                 goto failed_sbi;
 573         }
 574
 575         /*
 576          * If the superblock doesn't start on a hardware sector boundary,
 577          * calculate the offset.
 578          */
 579         if (blocksize != BLOCK_SIZE) {
 580                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 581                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 582         } else {
 583                 logic_sb_block = sb_block;
 584         }
 585
 586         if (!(bh = sb_bread(sb, logic_sb_block))) {
 587                 printk ("EXT2-fs: unable to read superblock\n");
 588                 goto failed_sbi;
 589         }
 590         /*
 591          * Note: s_es must be initialized as soon as possible because
 592          *       some ext2 macro-instructions depend on its value
 593          */
 594         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 595         sbi->s_es = es;
 596         sb->s_magic = le16_to_cpu(es->s_magic);
 597         sb->s_flags |= MS_ONE_SECOND;
 598         if (sb->s_magic != EXT2_SUPER_MAGIC) {
 599                 if (!silent)
 600                         printk ("VFS: Can't find ext2 filesystem on dev %s.\n",
 601                                 sb->s_id);
 602                 goto failed_mount;
 603         }
 604
 605         /* Set defaults before we parse the mount options */
 606         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 607         if (def_mount_opts & EXT2_DEFM_DEBUG)
 608                 set_opt(sbi->s_mount_opt, DEBUG);
 609         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 610                 set_opt(sbi->s_mount_opt, GRPID);
 611         if (def_mount_opts & EXT2_DEFM_UID16)
 612                 set_opt(sbi->s_mount_opt, NO_UID32);
 613         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 614                 set_opt(sbi->s_mount_opt, XATTR_USER);
 615         if (def_mount_opts & EXT2_DEFM_ACL)
 616                 set_opt(sbi->s_mount_opt, POSIX_ACL);
 617
 618         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 619                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 620         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
 621                 set_opt(sbi->s_mount_opt, ERRORS_RO);
 622
 623         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
 624         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
 625
 626         if (!parse_options ((char *) data, sbi))
 627                 goto failed_mount;
 628
 629         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 630                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 631                  MS_POSIXACL : 0);
 632
 633         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 634             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 635              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 636              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 637                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
 638                        "running e2fsck is recommended\n");
 639         /*
 640          * Check feature flags regardless of the revision level, since we
 641          * previously didn't change the revision level when setting the flags,
 642          * so there is a chance incompat flags are set on a rev 0 filesystem.
 643          */
 644         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 645         if (features) {
 646                 printk("EXT2-fs: %s: couldn't mount because of "
 647                        "unsupported optional features (%x).\n",
 648                        sb->s_id, le32_to_cpu(features));
 649                 goto failed_mount;
 650         }
 651         if (!(sb->s_flags & MS_RDONLY) &&
 652             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 653                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
 654                        "unsupported optional features (%x).\n",
 655                        sb->s_id, le32_to_cpu(features));
 656                 goto failed_mount;
 657         }
 658         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 659         /* If the blocksize doesn't match, re-read the thing.. */
 660         if (sb->s_blocksize != blocksize) {
 661                 brelse(bh);
 662
 663                 if (!sb_set_blocksize(sb, blocksize)) {
 664                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
 665                         goto failed_sbi;
 666                 }
 667
 668                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 669                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 670                 bh = sb_bread(sb, logic_sb_block);
 671                 if(!bh) {
 672                         printk("EXT2-fs: Couldn't read superblock on "
 673                                "2nd try.\n");
 674                         goto failed_sbi;
 675                 }
 676                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 677                 sbi->s_es = es;
 678                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 679                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
 680                         goto failed_mount;
 681                 }
 682         }
 683
 684         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 685
 686         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 687                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 688                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 689         } else {
 690                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 691                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 692                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 693                     (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
 694                     (sbi->s_inode_size > blocksize)) {
 695                         printk ("EXT2-fs: unsupported inode size: %d\n",
 696                                 sbi->s_inode_size);
 697                         goto failed_mount;
 698                 }
 699         }
 700         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 701                                    le32_to_cpu(es->s_log_frag_size);
 702         if (sbi->s_frag_size)
 703                 sbi->s_frags_per_block = sb->s_blocksize /
 704                                                   sbi->s_frag_size;
 705         else
 706                 sb->s_magic = 0;
 707         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 708         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 709         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 710         sbi->s_inodes_per_block = sb->s_blocksize /
 711                                            EXT2_INODE_SIZE(sb);
 712         sbi->s_itb_per_group = sbi->s_inodes_per_group /
 713                                         sbi->s_inodes_per_block;
 714         sbi->s_desc_per_block = sb->s_blocksize /
 715                                          sizeof (struct ext2_group_desc);
 716         sbi->s_sbh = bh;
 717         sbi->s_mount_state = le16_to_cpu(es->s_state);
 718         sbi->s_addr_per_block_bits =
 719                 log2 (EXT2_ADDR_PER_BLOCK(sb));
 720         sbi->s_desc_per_block_bits =
 721                 log2 (EXT2_DESC_PER_BLOCK(sb));
 722         if (sb->s_magic != EXT2_SUPER_MAGIC) {
 723                 if (!silent)
 724                         printk ("VFS: Can't find an ext2 filesystem on dev "
 725                                 "%s.\n",
 726                                 sb->s_id);
 727                 goto failed_mount;
 728         }
 729         if (sb->s_blocksize != bh->b_size) {
 730                 if (!silent)
 731                         printk ("VFS: Unsupported blocksize on dev "
 732                                 "%s.\n", sb->s_id);
 733                 goto failed_mount;
 734         }
 735
 736         if (sb->s_blocksize != sbi->s_frag_size) {
 737                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
 738                         sbi->s_frag_size, sb->s_blocksize);
 739                 goto failed_mount;
 740         }
 741
 742         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
 743                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
 744                         sbi->s_blocks_per_group);
 745                 goto failed_mount;
 746         }
 747         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 748                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
 749                         sbi->s_frags_per_group);
 750                 goto failed_mount;
 751         }
 752         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
 753                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
 754                         sbi->s_inodes_per_group);
 755                 goto failed_mount;
 756         }
 757
 758         sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) -
 759                                         le32_to_cpu(es->s_first_data_block) +
 760                                        EXT2_BLOCKS_PER_GROUP(sb) - 1) /
 761                                        EXT2_BLOCKS_PER_GROUP(sb);
 762         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
 763                    EXT2_DESC_PER_BLOCK(sb);
 764         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
 765         if (sbi->s_group_desc == NULL) {
 766                 printk ("EXT2-fs: not enough memory\n");
 767                 goto failed_mount;
 768         }
 769         percpu_counter_init(&sbi->s_freeblocks_counter);
 770         percpu_counter_init(&sbi->s_freeinodes_counter);
 771         percpu_counter_init(&sbi->s_dirs_counter);
 772         bgl_lock_init(&sbi->s_blockgroup_lock);
 773         sbi->s_debts = kmalloc(sbi->s_groups_count * sizeof(*sbi->s_debts),
 774                                GFP_KERNEL);
 775         if (!sbi->s_debts) {
 776                 printk ("EXT2-fs: not enough memory\n");
 777                 goto failed_mount_group_desc;
 778         }
 779         memset(sbi->s_debts, 0, sbi->s_groups_count * sizeof(*sbi->s_debts));
 780         for (i = 0; i < db_count; i++) {
 781                 block = descriptor_loc(sb, logic_sb_block, i);
 782                 sbi->s_group_desc[i] = sb_bread(sb, block);
 783                 if (!sbi->s_group_desc[i]) {
 784                         for (j = 0; j < i; j++)
 785                                 brelse (sbi->s_group_desc[j]);
 786                         printk ("EXT2-fs: unable to read group descriptors\n");
 787                         goto failed_mount_group_desc;
 788                 }
 789         }
 790         if (!ext2_check_descriptors (sb)) {
 791                 printk ("EXT2-fs: group descriptors corrupted!\n");
 792                 db_count = i;
 793                 goto failed_mount2;
 794         }
 795         sbi->s_gdb_count = db_count;
 796         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
 797         spin_lock_init(&sbi->s_next_gen_lock);
 798         /*
 799          * set up enough so that it can read an inode
 800          */
 801         sb->s_op = &ext2_sops;
 802         sb->s_export_op = &ext2_export_ops;
 803         root = iget(sb, EXT2_ROOT_INO);
 804         sb->s_root = d_alloc_root(root);
 805         if (!sb->s_root) {
 806                 iput(root);
 807                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
 808                 goto failed_mount2;
 809         }
 810         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
 811                 dput(sb->s_root);
 812                 sb->s_root = NULL;
 813                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
 814                 goto failed_mount2;
 815         }
 816         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 817                 ext2_warning(sb, __FUNCTION__,
 818                         "mounting ext3 filesystem as ext2\n");
 819         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
 820         percpu_counter_mod(&sbi->s_freeblocks_counter,
 821                                 ext2_count_free_blocks(sb));
 822         percpu_counter_mod(&sbi->s_freeinodes_counter,
 823                                 ext2_count_free_inodes(sb));
 824         percpu_counter_mod(&sbi->s_dirs_counter,
 825                                 ext2_count_dirs(sb));
 826         return 0;
 827 failed_mount2:
 828         for (i = 0; i < db_count; i++)
 829                 brelse(sbi->s_group_desc[i]);
 830 failed_mount_group_desc:
 831         kfree(sbi->s_group_desc);
 832         if (sbi->s_debts)
 833                 kfree(sbi->s_debts);
 834 failed_mount:
 835         brelse(bh);
 836 failed_sbi:
 837         sb->s_fs_info = NULL;
 838         kfree(sbi);
 839         return -EINVAL;
 840 }
 841
 842 static void ext2_commit_super (struct super_block * sb,
 843                                struct ext2_super_block * es)
 844 {
 845         es->s_wtime = cpu_to_le32(get_seconds());
 846         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 847         sb->s_dirt = 0;
 848 }
 849
 850 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
 851 {
 852         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 853         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 854         es->s_wtime = cpu_to_le32(get_seconds());
 855         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 856         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
 857         sb->s_dirt = 0;
 858 }
 859
 860 /*
 861  * In the second extended file system, it is not necessary to
 862  * write the super block since we use a mapping of the
 863  * disk super block in a buffer.
 864  *
 865  * However, this function is still used to set the fs valid
 866  * flags to 0.  We need to set this flag to 0 since the fs
 867  * may have been checked while mounted and e2fsck may have
 868  * set s_state to EXT2_VALID_FS after some corrections.
 869  */
 870
 871 void ext2_write_super (struct super_block * sb)
 872 {
 873         struct ext2_super_block * es;
 874         lock_kernel();
 875         if (!(sb->s_flags & MS_RDONLY)) {
 876                 es = EXT2_SB(sb)->s_es;
 877
 878                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
 879                         ext2_debug ("setting valid to 0\n");
 880                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
 881                                                   ~EXT2_VALID_FS);
 882                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 883                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 884                         es->s_mtime = cpu_to_le32(get_seconds());
 885                         ext2_sync_super(sb, es);
 886                 } else
 887                         ext2_commit_super (sb, es);
 888         }
 889         sb->s_dirt = 0;
 890         unlock_kernel();
 891 }
 892
 893 static int ext2_remount (struct super_block * sb, int * flags, char * data)
 894 {
 895         struct ext2_sb_info * sbi = EXT2_SB(sb);
 896         struct ext2_super_block * es;
 897
 898         /*
 899          * Allow the "check" option to be passed as a remount option.
 900          */
 901         if (!parse_options (data, sbi))
 902                 return -EINVAL;
 903
 904         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 905                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
 906
 907         es = sbi->s_es;
 908         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 909                 return 0;
 910         if (*flags & MS_RDONLY) {
 911                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
 912                     !(sbi->s_mount_state & EXT2_VALID_FS))
 913                         return 0;
 914                 /*
 915                  * OK, we are remounting a valid rw partition rdonly, so set
 916                  * the rdonly flag and then mark the partition as valid again.
 917                  */
 918                 es->s_state = cpu_to_le16(sbi->s_mount_state);
 919                 es->s_mtime = cpu_to_le32(get_seconds());
 920         } else {
 921                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
 922                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
 923                 if (ret) {
 924                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
 925                                "unsupported optional features (%x).\n",
 926                                sb->s_id, le32_to_cpu(ret));
 927                         return -EROFS;
 928                 }
 929                 /*
 930                  * Mounting a RDONLY partition read-write, so reread and
 931                  * store the current valid flag.  (It may have been changed
 932                  * by e2fsck since we originally mounted the partition.)
 933                  */
 934                 sbi->s_mount_state = le16_to_cpu(es->s_state);
 935                 if (!ext2_setup_super (sb, es, 0))
 936                         sb->s_flags &= ~MS_RDONLY;
 937         }
 938         ext2_sync_super(sb, es);
 939         return 0;
 940 }
 941
 942 static int ext2_statfs (struct super_block * sb, struct kstatfs * buf)
 943 {
 944         struct ext2_sb_info *sbi = EXT2_SB(sb);
 945         unsigned long overhead;
 946         int i;
 947
 948         if (test_opt (sb, MINIX_DF))
 949                 overhead = 0;
 950         else {
 951                 /*
 952                  * Compute the overhead (FS structures)
 953                  */
 954
 955                 /*
 956                  * All of the blocks before first_data_block are
 957                  * overhead
 958                  */
 959                 overhead = le32_to_cpu(sbi->s_es->s_first_data_block);
 960
 961                 /*
 962                  * Add the overhead attributed to the superblock and
 963                  * block group descriptors.  If the sparse superblocks
 964                  * feature is turned on, then not all groups have this.
 965                  */
 966                 for (i = 0; i < sbi->s_groups_count; i++)
 967                         overhead += ext2_bg_has_super(sb, i) +
 968                                 ext2_bg_num_gdb(sb, i);
 969
 970                 /*
 971                  * Every block group has an inode bitmap, a block
 972                  * bitmap, and an inode table.
 973                  */
 974                 overhead += (sbi->s_groups_count *
 975                              (2 + sbi->s_itb_per_group));
 976         }
 977
 978         buf->f_type = EXT2_SUPER_MAGIC;
 979         buf->f_bsize = sb->s_blocksize;
 980         buf->f_blocks = le32_to_cpu(sbi->s_es->s_blocks_count) - overhead;
 981         buf->f_bfree = ext2_count_free_blocks(sb);
 982         buf->f_bavail = buf->f_bfree - le32_to_cpu(sbi->s_es->s_r_blocks_count);
 983         if (buf->f_bfree < le32_to_cpu(sbi->s_es->s_r_blocks_count))
 984                 buf->f_bavail = 0;
 985         buf->f_files = le32_to_cpu(sbi->s_es->s_inodes_count);
 986         buf->f_ffree = ext2_count_free_inodes (sb);
 987         buf->f_namelen = EXT2_NAME_LEN;
 988         return 0;
 989 }
 990
 991 static struct super_block *ext2_get_sb(struct file_system_type *fs_type,
 992         int flags, const char *dev_name, void *data)
 993 {
 994         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
 995 }
 996
 997 static struct file_system_type ext2_fs_type = {
 998         .owner          = THIS_MODULE,
 999         .name           = "ext2",
1000         .get_sb         = ext2_get_sb,
1001         .kill_sb        = kill_block_super,
1002         .fs_flags       = FS_REQUIRES_DEV,
1003 };
1004
1005 static int __init init_ext2_fs(void)
1006 {
1007         int err = init_ext2_xattr();
1008         if (err)
1009                 return err;
1010         err = init_inodecache();
1011         if (err)
1012                 goto out1;
1013         err = register_filesystem(&ext2_fs_type);
1014         if (err)
1015                 goto out;
1016         return 0;
1017 out:
1018         destroy_inodecache();
1019 out1:
1020         exit_ext2_xattr();
1021         return err;
1022 }
1023
1024 static void __exit exit_ext2_fs(void)
1025 {
1026         unregister_filesystem(&ext2_fs_type);
1027         destroy_inodecache();
1028         exit_ext2_xattr();
1029 }
1030
1031 module_init(init_ext2_fs)
1032 module_exit(exit_ext2_fs)