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, Opt_tagxid,
 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_tagxid, "tagxid"},
 282         {Opt_ignore, "grpquota"},
 283         {Opt_ignore, "noquota"},
 284         {Opt_ignore, "quota"},
 285         {Opt_ignore, "usrquota"},
 286         {Opt_err, NULL}
 287 };
 288
 289 static int parse_options (char * options,
 290                           struct ext2_sb_info *sbi)
 291 {
 292         char * p;
 293         substring_t args[MAX_OPT_ARGS];
 294         unsigned long kind = EXT2_MOUNT_ERRORS_CONT;
 295         int option;
 296
 297         if (!options)
 298                 return 1;
 299
 300         while ((p = strsep (&options, ",")) != NULL) {
 301                 int token;
 302                 if (!*p)
 303                         continue;
 304
 305                 token = match_token(p, tokens, args);
 306                 switch (token) {
 307                 case Opt_bsd_df:
 308                         clear_opt (sbi->s_mount_opt, MINIX_DF);
 309                         break;
 310                 case Opt_minix_df:
 311                         set_opt (sbi->s_mount_opt, MINIX_DF);
 312                         break;
 313                 case Opt_grpid:
 314                         set_opt (sbi->s_mount_opt, GRPID);
 315                         break;
 316                 case Opt_nogrpid:
 317                         clear_opt (sbi->s_mount_opt, GRPID);
 318                         break;
 319                 case Opt_resuid:
 320                         if (match_int(&args[0], &option))
 321                                 return 0;
 322                         sbi->s_resuid = option;
 323                         break;
 324                 case Opt_resgid:
 325                         if (match_int(&args[0], &option))
 326                                 return 0;
 327                         sbi->s_resgid = option;
 328                         break;
 329                 case Opt_sb:
 330                         /* handled by get_sb_block() instead of here */
 331                         /* *sb_block = match_int(&args[0]); */
 332                         break;
 333                 case Opt_err_panic:
 334                         kind = EXT2_MOUNT_ERRORS_PANIC;
 335                         break;
 336                 case Opt_err_ro:
 337                         kind = EXT2_MOUNT_ERRORS_RO;
 338                         break;
 339                 case Opt_err_cont:
 340                         kind = EXT2_MOUNT_ERRORS_CONT;
 341                         break;
 342                 case Opt_nouid32:
 343                         set_opt (sbi->s_mount_opt, NO_UID32);
 344                         break;
 345 #ifndef CONFIG_INOXID_NONE
 346                 case Opt_tagxid:
 347                         set_opt (sbi->s_mount_opt, TAG_XID);
 348                         break;
 349 #endif
 350                 case Opt_check:
 351 #ifdef CONFIG_EXT2_CHECK
 352                         set_opt (sbi->s_mount_opt, CHECK);
 353 #else
 354                         printk("EXT2 Check option not supported\n");
 355 #endif
 356                         break;
 357                 case Opt_nocheck:
 358                         clear_opt (sbi->s_mount_opt, CHECK);
 359                         break;
 360                 case Opt_debug:
 361                         set_opt (sbi->s_mount_opt, DEBUG);
 362                         break;
 363                 case Opt_oldalloc:
 364                         set_opt (sbi->s_mount_opt, OLDALLOC);
 365                         break;
 366                 case Opt_orlov:
 367                         clear_opt (sbi->s_mount_opt, OLDALLOC);
 368                         break;
 369                 case Opt_nobh:
 370                         set_opt (sbi->s_mount_opt, NOBH);
 371                         break;
 372 #ifdef CONFIG_EXT2_FS_XATTR
 373                 case Opt_user_xattr:
 374                         set_opt (sbi->s_mount_opt, XATTR_USER);
 375                         break;
 376                 case Opt_nouser_xattr:
 377                         clear_opt (sbi->s_mount_opt, XATTR_USER);
 378                         break;
 379 #else
 380                 case Opt_user_xattr:
 381                 case Opt_nouser_xattr:
 382                         printk("EXT2 (no)user_xattr options not supported\n");
 383                         break;
 384 #endif
 385 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 386                 case Opt_acl:
 387                         set_opt(sbi->s_mount_opt, POSIX_ACL);
 388                         break;
 389                 case Opt_noacl:
 390                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
 391                         break;
 392 #else
 393                 case Opt_acl:
 394                 case Opt_noacl:
 395                         printk("EXT2 (no)acl options not supported\n");
 396                         break;
 397 #endif
 398                 case Opt_ignore:
 399                         break;
 400                 default:
 401                         return 0;
 402                 }
 403         }
 404         sbi->s_mount_opt |= kind;
 405         return 1;
 406 }
 407
 408 static int ext2_setup_super (struct super_block * sb,
 409                               struct ext2_super_block * es,
 410                               int read_only)
 411 {
 412         int res = 0;
 413         struct ext2_sb_info *sbi = EXT2_SB(sb);
 414
 415         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 416                 printk ("EXT2-fs warning: revision level too high, "
 417                         "forcing read-only mode\n");
 418                 res = MS_RDONLY;
 419         }
 420         if (read_only)
 421                 return res;
 422         if (!(sbi->s_mount_state & EXT2_VALID_FS))
 423                 printk ("EXT2-fs warning: mounting unchecked fs, "
 424                         "running e2fsck is recommended\n");
 425         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 426                 printk ("EXT2-fs warning: mounting fs with errors, "
 427                         "running e2fsck is recommended\n");
 428         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 429                  le16_to_cpu(es->s_mnt_count) >=
 430                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 431                 printk ("EXT2-fs warning: maximal mount count reached, "
 432                         "running e2fsck is recommended\n");
 433         else if (le32_to_cpu(es->s_checkinterval) &&
 434                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 435                 printk ("EXT2-fs warning: checktime reached, "
 436                         "running e2fsck is recommended\n");
 437         if (!le16_to_cpu(es->s_max_mnt_count))
 438                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 439         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
 440         ext2_write_super(sb);
 441         if (test_opt (sb, DEBUG))
 442                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
 443                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
 444                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 445                         sbi->s_frag_size,
 446                         sbi->s_groups_count,
 447                         EXT2_BLOCKS_PER_GROUP(sb),
 448                         EXT2_INODES_PER_GROUP(sb),
 449                         sbi->s_mount_opt);
 450 #ifdef CONFIG_EXT2_CHECK
 451         if (test_opt (sb, CHECK)) {
 452                 ext2_check_blocks_bitmap (sb);
 453                 ext2_check_inodes_bitmap (sb);
 454         }
 455 #endif
 456         return res;
 457 }
 458
 459 static int ext2_check_descriptors (struct super_block * sb)
 460 {
 461         int i;
 462         int desc_block = 0;
 463         struct ext2_sb_info *sbi = EXT2_SB(sb);
 464         unsigned long block = le32_to_cpu(sbi->s_es->s_first_data_block);
 465         struct ext2_group_desc * gdp = NULL;
 466
 467         ext2_debug ("Checking group descriptors");
 468
 469         for (i = 0; i < sbi->s_groups_count; i++)
 470         {
 471                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
 472                         gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
 473                 if (le32_to_cpu(gdp->bg_block_bitmap) < block ||
 474                     le32_to_cpu(gdp->bg_block_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 475                 {
 476                         ext2_error (sb, "ext2_check_descriptors",
 477                                     "Block bitmap for group %d"
 478                                     " not in group (block %lu)!",
 479                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 480                         return 0;
 481                 }
 482                 if (le32_to_cpu(gdp->bg_inode_bitmap) < block ||
 483                     le32_to_cpu(gdp->bg_inode_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 484                 {
 485                         ext2_error (sb, "ext2_check_descriptors",
 486                                     "Inode bitmap for group %d"
 487                                     " not in group (block %lu)!",
 488                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 489                         return 0;
 490                 }
 491                 if (le32_to_cpu(gdp->bg_inode_table) < block ||
 492                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >=
 493                     block + EXT2_BLOCKS_PER_GROUP(sb))
 494                 {
 495                         ext2_error (sb, "ext2_check_descriptors",
 496                                     "Inode table for group %d"
 497                                     " not in group (block %lu)!",
 498                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 499                         return 0;
 500                 }
 501                 block += EXT2_BLOCKS_PER_GROUP(sb);
 502                 gdp++;
 503         }
 504         return 1;
 505 }
 506
 507 #define log2(n) ffz(~(n))
 508
 509 /*
 510  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 511  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 512  * We need to be 1 filesystem block less than the 2^32 sector limit.
 513  */
 514 static loff_t ext2_max_size(int bits)
 515 {
 516         loff_t res = EXT2_NDIR_BLOCKS;
 517         res += 1LL << (bits-2);
 518         res += 1LL << (2*(bits-2));
 519         res += 1LL << (3*(bits-2));
 520         res <<= bits;
 521         if (res > (512LL << 32) - (1 << bits))
 522                 res = (512LL << 32) - (1 << bits);
 523         return res;
 524 }
 525
 526 static unsigned long descriptor_loc(struct super_block *sb,
 527                                     unsigned long logic_sb_block,
 528                                     int nr)
 529 {
 530         struct ext2_sb_info *sbi = EXT2_SB(sb);
 531         unsigned long bg, first_data_block, first_meta_bg;
 532         int has_super = 0;
 533
 534         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 535         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 536
 537         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 538             nr < first_meta_bg)
 539                 return (logic_sb_block + nr + 1);
 540         bg = sbi->s_desc_per_block * nr;
 541         if (ext2_bg_has_super(sb, bg))
 542                 has_super = 1;
 543         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
 544 }
 545
 546 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 547 {
 548         struct buffer_head * bh;
 549         struct ext2_sb_info * sbi;
 550         struct ext2_super_block * es;
 551         struct inode *root;
 552         unsigned long block;
 553         unsigned long sb_block = get_sb_block(&data);
 554         unsigned long logic_sb_block;
 555         unsigned long offset = 0;
 556         unsigned long def_mount_opts;
 557         int blocksize = BLOCK_SIZE;
 558         int db_count;
 559         int i, j;
 560         __le32 features;
 561
 562         sbi = kmalloc(sizeof(*sbi), GFP_KERNEL);
 563         if (!sbi)
 564                 return -ENOMEM;
 565         sb->s_fs_info = sbi;
 566         memset(sbi, 0, sizeof(*sbi));
 567
 568         /*
 569          * See what the current blocksize for the device is, and
 570          * use that as the blocksize.  Otherwise (or if the blocksize
 571          * is smaller than the default) use the default.
 572          * This is important for devices that have a hardware
 573          * sectorsize that is larger than the default.
 574          */
 575         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 576         if (!blocksize) {
 577                 printk ("EXT2-fs: unable to set blocksize\n");
 578                 goto failed_sbi;
 579         }
 580
 581         /*
 582          * If the superblock doesn't start on a hardware sector boundary,
 583          * calculate the offset.
 584          */
 585         if (blocksize != BLOCK_SIZE) {
 586                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 587                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 588         } else {
 589                 logic_sb_block = sb_block;
 590         }
 591
 592         if (!(bh = sb_bread(sb, logic_sb_block))) {
 593                 printk ("EXT2-fs: unable to read superblock\n");
 594                 goto failed_sbi;
 595         }
 596         /*
 597          * Note: s_es must be initialized as soon as possible because
 598          *       some ext2 macro-instructions depend on its value
 599          */
 600         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 601         sbi->s_es = es;
 602         sb->s_magic = le16_to_cpu(es->s_magic);
 603         sb->s_flags |= MS_ONE_SECOND;
 604         if (sb->s_magic != EXT2_SUPER_MAGIC) {
 605                 if (!silent)
 606                         printk ("VFS: Can't find ext2 filesystem on dev %s.\n",
 607                                 sb->s_id);
 608                 goto failed_mount;
 609         }
 610
 611         /* Set defaults before we parse the mount options */
 612         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 613         if (def_mount_opts & EXT2_DEFM_DEBUG)
 614                 set_opt(sbi->s_mount_opt, DEBUG);
 615         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 616                 set_opt(sbi->s_mount_opt, GRPID);
 617         if (def_mount_opts & EXT2_DEFM_UID16)
 618                 set_opt(sbi->s_mount_opt, NO_UID32);
 619         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 620                 set_opt(sbi->s_mount_opt, XATTR_USER);
 621         if (def_mount_opts & EXT2_DEFM_ACL)
 622                 set_opt(sbi->s_mount_opt, POSIX_ACL);
 623
 624         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 625                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 626         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
 627                 set_opt(sbi->s_mount_opt, ERRORS_RO);
 628
 629         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
 630         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
 631
 632         if (!parse_options ((char *) data, sbi))
 633                 goto failed_mount;
 634
 635         if (EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_TAG_XID)
 636                 sb->s_flags |= MS_TAGXID;
 637         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 638                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 639                  MS_POSIXACL : 0);
 640
 641         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 642             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 643              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 644              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 645                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
 646                        "running e2fsck is recommended\n");
 647         /*
 648          * Check feature flags regardless of the revision level, since we
 649          * previously didn't change the revision level when setting the flags,
 650          * so there is a chance incompat flags are set on a rev 0 filesystem.
 651          */
 652         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 653         if (features) {
 654                 printk("EXT2-fs: %s: couldn't mount because of "
 655                        "unsupported optional features (%x).\n",
 656                        sb->s_id, le32_to_cpu(features));
 657                 goto failed_mount;
 658         }
 659         if (!(sb->s_flags & MS_RDONLY) &&
 660             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 661                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
 662                        "unsupported optional features (%x).\n",
 663                        sb->s_id, le32_to_cpu(features));
 664                 goto failed_mount;
 665         }
 666         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 667         /* If the blocksize doesn't match, re-read the thing.. */
 668         if (sb->s_blocksize != blocksize) {
 669                 brelse(bh);
 670
 671                 if (!sb_set_blocksize(sb, blocksize)) {
 672                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
 673                         goto failed_sbi;
 674                 }
 675
 676                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 677                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 678                 bh = sb_bread(sb, logic_sb_block);
 679                 if(!bh) {
 680                         printk("EXT2-fs: Couldn't read superblock on "
 681                                "2nd try.\n");
 682                         goto failed_sbi;
 683                 }
 684                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 685                 sbi->s_es = es;
 686                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 687                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
 688                         goto failed_mount;
 689                 }
 690         }
 691
 692         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 693
 694         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 695                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 696                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 697         } else {
 698                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 699                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 700                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 701                     (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
 702                     (sbi->s_inode_size > blocksize)) {
 703                         printk ("EXT2-fs: unsupported inode size: %d\n",
 704                                 sbi->s_inode_size);
 705                         goto failed_mount;
 706                 }
 707         }
 708         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 709                                    le32_to_cpu(es->s_log_frag_size);
 710         if (sbi->s_frag_size)
 711                 sbi->s_frags_per_block = sb->s_blocksize /
 712                                                   sbi->s_frag_size;
 713         else
 714                 sb->s_magic = 0;
 715         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 716         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 717         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 718         sbi->s_inodes_per_block = sb->s_blocksize /
 719                                            EXT2_INODE_SIZE(sb);
 720         sbi->s_itb_per_group = sbi->s_inodes_per_group /
 721                                         sbi->s_inodes_per_block;
 722         sbi->s_desc_per_block = sb->s_blocksize /
 723                                          sizeof (struct ext2_group_desc);
 724         sbi->s_sbh = bh;
 725         sbi->s_mount_state = le16_to_cpu(es->s_state);
 726         sbi->s_addr_per_block_bits =
 727                 log2 (EXT2_ADDR_PER_BLOCK(sb));
 728         sbi->s_desc_per_block_bits =
 729                 log2 (EXT2_DESC_PER_BLOCK(sb));
 730         if (sb->s_magic != EXT2_SUPER_MAGIC) {
 731                 if (!silent)
 732                         printk ("VFS: Can't find an ext2 filesystem on dev "
 733                                 "%s.\n",
 734                                 sb->s_id);
 735                 goto failed_mount;
 736         }
 737         if (sb->s_blocksize != bh->b_size) {
 738                 if (!silent)
 739                         printk ("VFS: Unsupported blocksize on dev "
 740                                 "%s.\n", sb->s_id);
 741                 goto failed_mount;
 742         }
 743
 744         if (sb->s_blocksize != sbi->s_frag_size) {
 745                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
 746                         sbi->s_frag_size, sb->s_blocksize);
 747                 goto failed_mount;
 748         }
 749
 750         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
 751                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
 752                         sbi->s_blocks_per_group);
 753                 goto failed_mount;
 754         }
 755         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 756                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
 757                         sbi->s_frags_per_group);
 758                 goto failed_mount;
 759         }
 760         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
 761                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
 762                         sbi->s_inodes_per_group);
 763                 goto failed_mount;
 764         }
 765
 766         sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) -
 767                                         le32_to_cpu(es->s_first_data_block) +
 768                                        EXT2_BLOCKS_PER_GROUP(sb) - 1) /
 769                                        EXT2_BLOCKS_PER_GROUP(sb);
 770         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
 771                    EXT2_DESC_PER_BLOCK(sb);
 772         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
 773         if (sbi->s_group_desc == NULL) {
 774                 printk ("EXT2-fs: not enough memory\n");
 775                 goto failed_mount;
 776         }
 777         percpu_counter_init(&sbi->s_freeblocks_counter);
 778         percpu_counter_init(&sbi->s_freeinodes_counter);
 779         percpu_counter_init(&sbi->s_dirs_counter);
 780         bgl_lock_init(&sbi->s_blockgroup_lock);
 781         sbi->s_debts = kmalloc(sbi->s_groups_count * sizeof(*sbi->s_debts),
 782                                GFP_KERNEL);
 783         if (!sbi->s_debts) {
 784                 printk ("EXT2-fs: not enough memory\n");
 785                 goto failed_mount_group_desc;
 786         }
 787         memset(sbi->s_debts, 0, sbi->s_groups_count * sizeof(*sbi->s_debts));
 788         for (i = 0; i < db_count; i++) {
 789                 block = descriptor_loc(sb, logic_sb_block, i);
 790                 sbi->s_group_desc[i] = sb_bread(sb, block);
 791                 if (!sbi->s_group_desc[i]) {
 792                         for (j = 0; j < i; j++)
 793                                 brelse (sbi->s_group_desc[j]);
 794                         printk ("EXT2-fs: unable to read group descriptors\n");
 795                         goto failed_mount_group_desc;
 796                 }
 797         }
 798         if (!ext2_check_descriptors (sb)) {
 799                 printk ("EXT2-fs: group descriptors corrupted!\n");
 800                 db_count = i;
 801                 goto failed_mount2;
 802         }
 803         sbi->s_gdb_count = db_count;
 804         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
 805         spin_lock_init(&sbi->s_next_gen_lock);
 806         /*
 807          * set up enough so that it can read an inode
 808          */
 809         sb->s_op = &ext2_sops;
 810         sb->s_export_op = &ext2_export_ops;
 811         root = iget(sb, EXT2_ROOT_INO);
 812         sb->s_root = d_alloc_root(root);
 813         if (!sb->s_root) {
 814                 iput(root);
 815                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
 816                 goto failed_mount2;
 817         }
 818         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
 819                 dput(sb->s_root);
 820                 sb->s_root = NULL;
 821                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
 822                 goto failed_mount2;
 823         }
 824         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 825                 ext2_warning(sb, __FUNCTION__,
 826                         "mounting ext3 filesystem as ext2\n");
 827         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
 828         percpu_counter_mod(&sbi->s_freeblocks_counter,
 829                                 ext2_count_free_blocks(sb));
 830         percpu_counter_mod(&sbi->s_freeinodes_counter,
 831                                 ext2_count_free_inodes(sb));
 832         percpu_counter_mod(&sbi->s_dirs_counter,
 833                                 ext2_count_dirs(sb));
 834         return 0;
 835 failed_mount2:
 836         for (i = 0; i < db_count; i++)
 837                 brelse(sbi->s_group_desc[i]);
 838 failed_mount_group_desc:
 839         kfree(sbi->s_group_desc);
 840         if (sbi->s_debts)
 841                 kfree(sbi->s_debts);
 842 failed_mount:
 843         brelse(bh);
 844 failed_sbi:
 845         sb->s_fs_info = NULL;
 846         kfree(sbi);
 847         return -EINVAL;
 848 }
 849
 850 static void ext2_commit_super (struct super_block * sb,
 851                                struct ext2_super_block * es)
 852 {
 853         es->s_wtime = cpu_to_le32(get_seconds());
 854         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 855         sb->s_dirt = 0;
 856 }
 857
 858 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
 859 {
 860         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 861         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 862         es->s_wtime = cpu_to_le32(get_seconds());
 863         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 864         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
 865         sb->s_dirt = 0;
 866 }
 867
 868 /*
 869  * In the second extended file system, it is not necessary to
 870  * write the super block since we use a mapping of the
 871  * disk super block in a buffer.
 872  *
 873  * However, this function is still used to set the fs valid
 874  * flags to 0.  We need to set this flag to 0 since the fs
 875  * may have been checked while mounted and e2fsck may have
 876  * set s_state to EXT2_VALID_FS after some corrections.
 877  */
 878
 879 void ext2_write_super (struct super_block * sb)
 880 {
 881         struct ext2_super_block * es;
 882         lock_kernel();
 883         if (!(sb->s_flags & MS_RDONLY)) {
 884                 es = EXT2_SB(sb)->s_es;
 885
 886                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
 887                         ext2_debug ("setting valid to 0\n");
 888                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
 889                                                   ~EXT2_VALID_FS);
 890                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 891                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 892                         es->s_mtime = cpu_to_le32(get_seconds());
 893                         ext2_sync_super(sb, es);
 894                 } else
 895                         ext2_commit_super (sb, es);
 896         }
 897         sb->s_dirt = 0;
 898         unlock_kernel();
 899 }
 900
 901 static int ext2_remount (struct super_block * sb, int * flags, char * data)
 902 {
 903         struct ext2_sb_info * sbi = EXT2_SB(sb);
 904         struct ext2_super_block * es;
 905
 906         /*
 907          * Allow the "check" option to be passed as a remount option.
 908          */
 909         if (!parse_options (data, sbi))
 910                 return -EINVAL;
 911
 912         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 913                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
 914
 915         es = sbi->s_es;
 916         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 917                 return 0;
 918         if (*flags & MS_RDONLY) {
 919                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
 920                     !(sbi->s_mount_state & EXT2_VALID_FS))
 921                         return 0;
 922                 /*
 923                  * OK, we are remounting a valid rw partition rdonly, so set
 924                  * the rdonly flag and then mark the partition as valid again.
 925                  */
 926                 es->s_state = cpu_to_le16(sbi->s_mount_state);
 927                 es->s_mtime = cpu_to_le32(get_seconds());
 928         } else {
 929                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
 930                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
 931                 if (ret) {
 932                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
 933                                "unsupported optional features (%x).\n",
 934                                sb->s_id, le32_to_cpu(ret));
 935                         return -EROFS;
 936                 }
 937                 /*
 938                  * Mounting a RDONLY partition read-write, so reread and
 939                  * store the current valid flag.  (It may have been changed
 940                  * by e2fsck since we originally mounted the partition.)
 941                  */
 942                 sbi->s_mount_state = le16_to_cpu(es->s_state);
 943                 if (!ext2_setup_super (sb, es, 0))
 944                         sb->s_flags &= ~MS_RDONLY;
 945         }
 946         ext2_sync_super(sb, es);
 947         return 0;
 948 }
 949
 950 static int ext2_statfs (struct super_block * sb, struct kstatfs * buf)
 951 {
 952         struct ext2_sb_info *sbi = EXT2_SB(sb);
 953         unsigned long overhead;
 954         int i;
 955
 956         if (test_opt (sb, MINIX_DF))
 957                 overhead = 0;
 958         else {
 959                 /*
 960                  * Compute the overhead (FS structures)
 961                  */
 962
 963                 /*
 964                  * All of the blocks before first_data_block are
 965                  * overhead
 966                  */
 967                 overhead = le32_to_cpu(sbi->s_es->s_first_data_block);
 968
 969                 /*
 970                  * Add the overhead attributed to the superblock and
 971                  * block group descriptors.  If the sparse superblocks
 972                  * feature is turned on, then not all groups have this.
 973                  */
 974                 for (i = 0; i < sbi->s_groups_count; i++)
 975                         overhead += ext2_bg_has_super(sb, i) +
 976                                 ext2_bg_num_gdb(sb, i);
 977
 978                 /*
 979                  * Every block group has an inode bitmap, a block
 980                  * bitmap, and an inode table.
 981                  */
 982                 overhead += (sbi->s_groups_count *
 983                              (2 + sbi->s_itb_per_group));
 984         }
 985
 986         buf->f_type = EXT2_SUPER_MAGIC;
 987         buf->f_bsize = sb->s_blocksize;
 988         buf->f_blocks = le32_to_cpu(sbi->s_es->s_blocks_count) - overhead;
 989         buf->f_bfree = ext2_count_free_blocks(sb);
 990         buf->f_bavail = buf->f_bfree - le32_to_cpu(sbi->s_es->s_r_blocks_count);
 991         if (buf->f_bfree < le32_to_cpu(sbi->s_es->s_r_blocks_count))
 992                 buf->f_bavail = 0;
 993         buf->f_files = le32_to_cpu(sbi->s_es->s_inodes_count);
 994         buf->f_ffree = ext2_count_free_inodes (sb);
 995         buf->f_namelen = EXT2_NAME_LEN;
 996         return 0;
 997 }
 998
 999 static struct super_block *ext2_get_sb(struct file_system_type *fs_type,
1000         int flags, const char *dev_name, void *data)
1001 {
1002         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1003 }
1004
1005 static struct file_system_type ext2_fs_type = {
1006         .owner          = THIS_MODULE,
1007         .name           = "ext2",
1008         .get_sb         = ext2_get_sb,
1009         .kill_sb        = kill_block_super,
1010         .fs_flags       = FS_REQUIRES_DEV,
1011 };
1012
1013 static int __init init_ext2_fs(void)
1014 {
1015         int err = init_ext2_xattr();
1016         if (err)
1017                 return err;
1018         err = init_inodecache();
1019         if (err)
1020                 goto out1;
1021         err = register_filesystem(&ext2_fs_type);
1022         if (err)
1023                 goto out;
1024         return 0;
1025 out:
1026         destroy_inodecache();
1027 out1:
1028         exit_ext2_xattr();
1029         return err;
1030 }
1031
1032 static void __exit exit_ext2_fs(void)
1033 {
1034         unregister_filesystem(&ext2_fs_type);
1035         destroy_inodecache();
1036         exit_ext2_xattr();
1037 }
1038
1039 module_init(init_ext2_fs)
1040 module_exit(exit_ext2_fs)