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         percpu_counter_destroy(&sbi->s_freeblocks_counter);
 126         percpu_counter_destroy(&sbi->s_freeinodes_counter);
 127         percpu_counter_destroy(&sbi->s_dirs_counter);
 128         brelse (sbi->s_sbh);
 129         sb->s_fs_info = NULL;
 130         kfree(sbi);
 131
 132         return;
 133 }
 134
 135 static kmem_cache_t * ext2_inode_cachep;
 136
 137 static struct inode *ext2_alloc_inode(struct super_block *sb)
 138 {
 139         struct ext2_inode_info *ei;
 140         ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, SLAB_KERNEL);
 141         if (!ei)
 142                 return NULL;
 143 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 144         ei->i_acl = EXT2_ACL_NOT_CACHED;
 145         ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 146 #endif
 147         ei->vfs_inode.i_version = 1;
 148         return &ei->vfs_inode;
 149 }
 150
 151 static void ext2_destroy_inode(struct inode *inode)
 152 {
 153         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
 154 }
 155
 156 static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
 157 {
 158         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
 159
 160         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 161             SLAB_CTOR_CONSTRUCTOR) {
 162                 rwlock_init(&ei->i_meta_lock);
 163 #ifdef CONFIG_EXT2_FS_XATTR
 164                 init_rwsem(&ei->xattr_sem);
 165 #endif
 166                 inode_init_once(&ei->vfs_inode);
 167         }
 168 }
 169
 170 static int init_inodecache(void)
 171 {
 172         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
 173                                              sizeof(struct ext2_inode_info),
 174                                              0, SLAB_RECLAIM_ACCOUNT,
 175                                              init_once, NULL);
 176         if (ext2_inode_cachep == NULL)
 177                 return -ENOMEM;
 178         return 0;
 179 }
 180
 181 static void destroy_inodecache(void)
 182 {
 183         if (kmem_cache_destroy(ext2_inode_cachep))
 184                 printk(KERN_INFO "ext2_inode_cache: not all structures were freed\n");
 185 }
 186
 187 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 188
 189 static void ext2_clear_inode(struct inode *inode)
 190 {
 191         struct ext2_inode_info *ei = EXT2_I(inode);
 192
 193         if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
 194                 posix_acl_release(ei->i_acl);
 195                 ei->i_acl = EXT2_ACL_NOT_CACHED;
 196         }
 197         if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
 198                 posix_acl_release(ei->i_default_acl);
 199                 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 200         }
 201 }
 202
 203 #else
 204 # define ext2_clear_inode NULL
 205 #endif
 206
 207 static struct super_operations ext2_sops = {
 208         .alloc_inode    = ext2_alloc_inode,
 209         .destroy_inode  = ext2_destroy_inode,
 210         .read_inode     = ext2_read_inode,
 211         .write_inode    = ext2_write_inode,
 212         .put_inode      = ext2_put_inode,
 213         .delete_inode   = ext2_delete_inode,
 214         .put_super      = ext2_put_super,
 215         .write_super    = ext2_write_super,
 216         .statfs         = ext2_statfs,
 217         .remount_fs     = ext2_remount,
 218         .clear_inode    = ext2_clear_inode,
 219 };
 220
 221 /* Yes, most of these are left as NULL!!
 222  * A NULL value implies the default, which works with ext2-like file
 223  * systems, but can be improved upon.
 224  * Currently only get_parent is required.
 225  */
 226 struct dentry *ext2_get_parent(struct dentry *child);
 227 static struct export_operations ext2_export_ops = {
 228         .get_parent = ext2_get_parent,
 229 };
 230
 231 static unsigned long get_sb_block(void **data)
 232 {
 233         unsigned long   sb_block;
 234         char            *options = (char *) *data;
 235
 236         if (!options || strncmp(options, "sb=", 3) != 0)
 237                 return 1;       /* Default location */
 238         options += 3;
 239         sb_block = simple_strtoul(options, &options, 0);
 240         if (*options && *options != ',') {
 241                 printk("EXT2-fs: Invalid sb specification: %s\n",
 242                        (char *) *data);
 243                 return 1;
 244         }
 245         if (*options == ',')
 246                 options++;
 247         *data = (void *) options;
 248         return sb_block;
 249 }
 250
 251 enum {
 252         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
 253         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
 254         Opt_nouid32, Opt_check, Opt_nocheck, Opt_debug, Opt_oldalloc, Opt_orlov, Opt_nobh,
 255         Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl, Opt_tagxid,
 256         Opt_ignore, Opt_err,
 257 };
 258
 259 static match_table_t tokens = {
 260         {Opt_bsd_df, "bsddf"},
 261         {Opt_minix_df, "minixdf"},
 262         {Opt_grpid, "grpid"},
 263         {Opt_grpid, "bsdgroups"},
 264         {Opt_nogrpid, "nogrpid"},
 265         {Opt_nogrpid, "sysvgroups"},
 266         {Opt_resgid, "resgid=%u"},
 267         {Opt_resuid, "resuid=%u"},
 268         {Opt_sb, "sb=%u"},
 269         {Opt_err_cont, "errors=continue"},
 270         {Opt_err_panic, "errors=panic"},
 271         {Opt_err_ro, "errors=remount-ro"},
 272         {Opt_nouid32, "nouid32"},
 273         {Opt_nocheck, "check=none"},
 274         {Opt_nocheck, "nocheck"},
 275         {Opt_check, "check"},
 276         {Opt_debug, "debug"},
 277         {Opt_oldalloc, "oldalloc"},
 278         {Opt_orlov, "orlov"},
 279         {Opt_nobh, "nobh"},
 280         {Opt_user_xattr, "user_xattr"},
 281         {Opt_nouser_xattr, "nouser_xattr"},
 282         {Opt_acl, "acl"},
 283         {Opt_noacl, "noacl"},
 284         {Opt_tagxid, "tagxid"},
 285         {Opt_ignore, "grpquota"},
 286         {Opt_ignore, "noquota"},
 287         {Opt_ignore, "quota"},
 288         {Opt_ignore, "usrquota"},
 289         {Opt_err, NULL}
 290 };
 291
 292 static int parse_options (char * options,
 293                           struct ext2_sb_info *sbi)
 294 {
 295         char * p;
 296         substring_t args[MAX_OPT_ARGS];
 297         unsigned long kind = EXT2_MOUNT_ERRORS_CONT;
 298         int option;
 299
 300         if (!options)
 301                 return 1;
 302
 303         while ((p = strsep (&options, ",")) != NULL) {
 304                 int token;
 305                 if (!*p)
 306                         continue;
 307
 308                 token = match_token(p, tokens, args);
 309                 switch (token) {
 310                 case Opt_bsd_df:
 311                         clear_opt (sbi->s_mount_opt, MINIX_DF);
 312                         break;
 313                 case Opt_minix_df:
 314                         set_opt (sbi->s_mount_opt, MINIX_DF);
 315                         break;
 316                 case Opt_grpid:
 317                         set_opt (sbi->s_mount_opt, GRPID);
 318                         break;
 319                 case Opt_nogrpid:
 320                         clear_opt (sbi->s_mount_opt, GRPID);
 321                         break;
 322                 case Opt_resuid:
 323                         if (match_int(&args[0], &option))
 324                                 return 0;
 325                         sbi->s_resuid = option;
 326                         break;
 327                 case Opt_resgid:
 328                         if (match_int(&args[0], &option))
 329                                 return 0;
 330                         sbi->s_resgid = option;
 331                         break;
 332                 case Opt_sb:
 333                         /* handled by get_sb_block() instead of here */
 334                         /* *sb_block = match_int(&args[0]); */
 335                         break;
 336                 case Opt_err_panic:
 337                         kind = EXT2_MOUNT_ERRORS_PANIC;
 338                         break;
 339                 case Opt_err_ro:
 340                         kind = EXT2_MOUNT_ERRORS_RO;
 341                         break;
 342                 case Opt_err_cont:
 343                         kind = EXT2_MOUNT_ERRORS_CONT;
 344                         break;
 345                 case Opt_nouid32:
 346                         set_opt (sbi->s_mount_opt, NO_UID32);
 347                         break;
 348 #ifndef CONFIG_INOXID_NONE
 349                 case Opt_tagxid:
 350                         set_opt (sbi->s_mount_opt, TAG_XID);
 351                         break;
 352 #endif
 353                 case Opt_check:
 354 #ifdef CONFIG_EXT2_CHECK
 355                         set_opt (sbi->s_mount_opt, CHECK);
 356 #else
 357                         printk("EXT2 Check option not supported\n");
 358 #endif
 359                         break;
 360                 case Opt_nocheck:
 361                         clear_opt (sbi->s_mount_opt, CHECK);
 362                         break;
 363                 case Opt_debug:
 364                         set_opt (sbi->s_mount_opt, DEBUG);
 365                         break;
 366                 case Opt_oldalloc:
 367                         set_opt (sbi->s_mount_opt, OLDALLOC);
 368                         break;
 369                 case Opt_orlov:
 370                         clear_opt (sbi->s_mount_opt, OLDALLOC);
 371                         break;
 372                 case Opt_nobh:
 373                         set_opt (sbi->s_mount_opt, NOBH);
 374                         break;
 375 #ifdef CONFIG_EXT2_FS_XATTR
 376                 case Opt_user_xattr:
 377                         set_opt (sbi->s_mount_opt, XATTR_USER);
 378                         break;
 379                 case Opt_nouser_xattr:
 380                         clear_opt (sbi->s_mount_opt, XATTR_USER);
 381                         break;
 382 #else
 383                 case Opt_user_xattr:
 384                 case Opt_nouser_xattr:
 385                         printk("EXT2 (no)user_xattr options not supported\n");
 386                         break;
 387 #endif
 388 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 389                 case Opt_acl:
 390                         set_opt(sbi->s_mount_opt, POSIX_ACL);
 391                         break;
 392                 case Opt_noacl:
 393                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
 394                         break;
 395 #else
 396                 case Opt_acl:
 397                 case Opt_noacl:
 398                         printk("EXT2 (no)acl options not supported\n");
 399                         break;
 400 #endif
 401                 case Opt_ignore:
 402                         break;
 403                 default:
 404                         return 0;
 405                 }
 406         }
 407         sbi->s_mount_opt |= kind;
 408         return 1;
 409 }
 410
 411 static int ext2_setup_super (struct super_block * sb,
 412                               struct ext2_super_block * es,
 413                               int read_only)
 414 {
 415         int res = 0;
 416         struct ext2_sb_info *sbi = EXT2_SB(sb);
 417
 418         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 419                 printk ("EXT2-fs warning: revision level too high, "
 420                         "forcing read-only mode\n");
 421                 res = MS_RDONLY;
 422         }
 423         if (read_only)
 424                 return res;
 425         if (!(sbi->s_mount_state & EXT2_VALID_FS))
 426                 printk ("EXT2-fs warning: mounting unchecked fs, "
 427                         "running e2fsck is recommended\n");
 428         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 429                 printk ("EXT2-fs warning: mounting fs with errors, "
 430                         "running e2fsck is recommended\n");
 431         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 432                  le16_to_cpu(es->s_mnt_count) >=
 433                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 434                 printk ("EXT2-fs warning: maximal mount count reached, "
 435                         "running e2fsck is recommended\n");
 436         else if (le32_to_cpu(es->s_checkinterval) &&
 437                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 438                 printk ("EXT2-fs warning: checktime reached, "
 439                         "running e2fsck is recommended\n");
 440         if (!le16_to_cpu(es->s_max_mnt_count))
 441                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 442         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
 443         ext2_write_super(sb);
 444         if (test_opt (sb, DEBUG))
 445                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
 446                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
 447                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 448                         sbi->s_frag_size,
 449                         sbi->s_groups_count,
 450                         EXT2_BLOCKS_PER_GROUP(sb),
 451                         EXT2_INODES_PER_GROUP(sb),
 452                         sbi->s_mount_opt);
 453 #ifdef CONFIG_EXT2_CHECK
 454         if (test_opt (sb, CHECK)) {
 455                 ext2_check_blocks_bitmap (sb);
 456                 ext2_check_inodes_bitmap (sb);
 457         }
 458 #endif
 459         return res;
 460 }
 461
 462 static int ext2_check_descriptors (struct super_block * sb)
 463 {
 464         int i;
 465         int desc_block = 0;
 466         struct ext2_sb_info *sbi = EXT2_SB(sb);
 467         unsigned long block = le32_to_cpu(sbi->s_es->s_first_data_block);
 468         struct ext2_group_desc * gdp = NULL;
 469
 470         ext2_debug ("Checking group descriptors");
 471
 472         for (i = 0; i < sbi->s_groups_count; i++)
 473         {
 474                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
 475                         gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
 476                 if (le32_to_cpu(gdp->bg_block_bitmap) < block ||
 477                     le32_to_cpu(gdp->bg_block_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 478                 {
 479                         ext2_error (sb, "ext2_check_descriptors",
 480                                     "Block bitmap for group %d"
 481                                     " not in group (block %lu)!",
 482                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 483                         return 0;
 484                 }
 485                 if (le32_to_cpu(gdp->bg_inode_bitmap) < block ||
 486                     le32_to_cpu(gdp->bg_inode_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 487                 {
 488                         ext2_error (sb, "ext2_check_descriptors",
 489                                     "Inode bitmap for group %d"
 490                                     " not in group (block %lu)!",
 491                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 492                         return 0;
 493                 }
 494                 if (le32_to_cpu(gdp->bg_inode_table) < block ||
 495                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >=
 496                     block + EXT2_BLOCKS_PER_GROUP(sb))
 497                 {
 498                         ext2_error (sb, "ext2_check_descriptors",
 499                                     "Inode table for group %d"
 500                                     " not in group (block %lu)!",
 501                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 502                         return 0;
 503                 }
 504                 block += EXT2_BLOCKS_PER_GROUP(sb);
 505                 gdp++;
 506         }
 507         return 1;
 508 }
 509
 510 #define log2(n) ffz(~(n))
 511
 512 /*
 513  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 514  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 515  * We need to be 1 filesystem block less than the 2^32 sector limit.
 516  */
 517 static loff_t ext2_max_size(int bits)
 518 {
 519         loff_t res = EXT2_NDIR_BLOCKS;
 520         res += 1LL << (bits-2);
 521         res += 1LL << (2*(bits-2));
 522         res += 1LL << (3*(bits-2));
 523         res <<= bits;
 524         if (res > (512LL << 32) - (1 << bits))
 525                 res = (512LL << 32) - (1 << bits);
 526         return res;
 527 }
 528
 529 static unsigned long descriptor_loc(struct super_block *sb,
 530                                     unsigned long logic_sb_block,
 531                                     int nr)
 532 {
 533         struct ext2_sb_info *sbi = EXT2_SB(sb);
 534         unsigned long bg, first_data_block, first_meta_bg;
 535         int has_super = 0;
 536
 537         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 538         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 539
 540         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 541             nr < first_meta_bg)
 542                 return (logic_sb_block + nr + 1);
 543         bg = sbi->s_desc_per_block * nr;
 544         if (ext2_bg_has_super(sb, bg))
 545                 has_super = 1;
 546         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
 547 }
 548
 549 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 550 {
 551         struct buffer_head * bh;
 552         struct ext2_sb_info * sbi;
 553         struct ext2_super_block * es;
 554         struct inode *root;
 555         unsigned long block;
 556         unsigned long sb_block = get_sb_block(&data);
 557         unsigned long logic_sb_block;
 558         unsigned long offset = 0;
 559         unsigned long def_mount_opts;
 560         int blocksize = BLOCK_SIZE;
 561         int db_count;
 562         int i, j;
 563         __le32 features;
 564
 565         sbi = kmalloc(sizeof(*sbi), GFP_KERNEL);
 566         if (!sbi)
 567                 return -ENOMEM;
 568         sb->s_fs_info = sbi;
 569         memset(sbi, 0, sizeof(*sbi));
 570
 571         /*
 572          * See what the current blocksize for the device is, and
 573          * use that as the blocksize.  Otherwise (or if the blocksize
 574          * is smaller than the default) use the default.
 575          * This is important for devices that have a hardware
 576          * sectorsize that is larger than the default.
 577          */
 578         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 579         if (!blocksize) {
 580                 printk ("EXT2-fs: unable to set blocksize\n");
 581                 goto failed_sbi;
 582         }
 583
 584         /*
 585          * If the superblock doesn't start on a hardware sector boundary,
 586          * calculate the offset.
 587          */
 588         if (blocksize != BLOCK_SIZE) {
 589                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 590                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 591         } else {
 592                 logic_sb_block = sb_block;
 593         }
 594
 595         if (!(bh = sb_bread(sb, logic_sb_block))) {
 596                 printk ("EXT2-fs: unable to read superblock\n");
 597                 goto failed_sbi;
 598         }
 599         /*
 600          * Note: s_es must be initialized as soon as possible because
 601          *       some ext2 macro-instructions depend on its value
 602          */
 603         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 604         sbi->s_es = es;
 605         sb->s_magic = le16_to_cpu(es->s_magic);
 606         sb->s_flags |= MS_ONE_SECOND;
 607         if (sb->s_magic != EXT2_SUPER_MAGIC) {
 608                 if (!silent)
 609                         printk ("VFS: Can't find ext2 filesystem on dev %s.\n",
 610                                 sb->s_id);
 611                 goto failed_mount;
 612         }
 613
 614         /* Set defaults before we parse the mount options */
 615         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 616         if (def_mount_opts & EXT2_DEFM_DEBUG)
 617                 set_opt(sbi->s_mount_opt, DEBUG);
 618         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 619                 set_opt(sbi->s_mount_opt, GRPID);
 620         if (def_mount_opts & EXT2_DEFM_UID16)
 621                 set_opt(sbi->s_mount_opt, NO_UID32);
 622         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 623                 set_opt(sbi->s_mount_opt, XATTR_USER);
 624         if (def_mount_opts & EXT2_DEFM_ACL)
 625                 set_opt(sbi->s_mount_opt, POSIX_ACL);
 626
 627         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 628                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 629         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
 630                 set_opt(sbi->s_mount_opt, ERRORS_RO);
 631
 632         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
 633         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
 634
 635         if (!parse_options ((char *) data, sbi))
 636                 goto failed_mount;
 637
 638         if (EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_TAG_XID)
 639                 sb->s_flags |= MS_TAGXID;
 640         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 641                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 642                  MS_POSIXACL : 0);
 643
 644         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 645             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 646              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 647              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 648                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
 649                        "running e2fsck is recommended\n");
 650         /*
 651          * Check feature flags regardless of the revision level, since we
 652          * previously didn't change the revision level when setting the flags,
 653          * so there is a chance incompat flags are set on a rev 0 filesystem.
 654          */
 655         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 656         if (features) {
 657                 printk("EXT2-fs: %s: couldn't mount because of "
 658                        "unsupported optional features (%x).\n",
 659                        sb->s_id, le32_to_cpu(features));
 660                 goto failed_mount;
 661         }
 662         if (!(sb->s_flags & MS_RDONLY) &&
 663             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 664                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
 665                        "unsupported optional features (%x).\n",
 666                        sb->s_id, le32_to_cpu(features));
 667                 goto failed_mount;
 668         }
 669         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 670         /* If the blocksize doesn't match, re-read the thing.. */
 671         if (sb->s_blocksize != blocksize) {
 672                 brelse(bh);
 673
 674                 if (!sb_set_blocksize(sb, blocksize)) {
 675                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
 676                         goto failed_sbi;
 677                 }
 678
 679                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 680                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 681                 bh = sb_bread(sb, logic_sb_block);
 682                 if(!bh) {
 683                         printk("EXT2-fs: Couldn't read superblock on "
 684                                "2nd try.\n");
 685                         goto failed_sbi;
 686                 }
 687                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 688                 sbi->s_es = es;
 689                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 690                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
 691                         goto failed_mount;
 692                 }
 693         }
 694
 695         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 696
 697         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 698                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 699                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 700         } else {
 701                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 702                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 703                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 704                     (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
 705                     (sbi->s_inode_size > blocksize)) {
 706                         printk ("EXT2-fs: unsupported inode size: %d\n",
 707                                 sbi->s_inode_size);
 708                         goto failed_mount;
 709                 }
 710         }
 711         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 712                                    le32_to_cpu(es->s_log_frag_size);
 713         if (sbi->s_frag_size)
 714                 sbi->s_frags_per_block = sb->s_blocksize /
 715                                                   sbi->s_frag_size;
 716         else
 717                 sb->s_magic = 0;
 718         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 719         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 720         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 721         sbi->s_inodes_per_block = sb->s_blocksize /
 722                                            EXT2_INODE_SIZE(sb);
 723         sbi->s_itb_per_group = sbi->s_inodes_per_group /
 724                                         sbi->s_inodes_per_block;
 725         sbi->s_desc_per_block = sb->s_blocksize /
 726                                          sizeof (struct ext2_group_desc);
 727         sbi->s_sbh = bh;
 728         sbi->s_mount_state = le16_to_cpu(es->s_state);
 729         sbi->s_addr_per_block_bits =
 730                 log2 (EXT2_ADDR_PER_BLOCK(sb));
 731         sbi->s_desc_per_block_bits =
 732                 log2 (EXT2_DESC_PER_BLOCK(sb));
 733         if (sb->s_magic != EXT2_SUPER_MAGIC) {
 734                 if (!silent)
 735                         printk ("VFS: Can't find an ext2 filesystem on dev "
 736                                 "%s.\n",
 737                                 sb->s_id);
 738                 goto failed_mount;
 739         }
 740         if (sb->s_blocksize != bh->b_size) {
 741                 if (!silent)
 742                         printk ("VFS: Unsupported blocksize on dev "
 743                                 "%s.\n", sb->s_id);
 744                 goto failed_mount;
 745         }
 746
 747         if (sb->s_blocksize != sbi->s_frag_size) {
 748                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
 749                         sbi->s_frag_size, sb->s_blocksize);
 750                 goto failed_mount;
 751         }
 752
 753         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
 754                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
 755                         sbi->s_blocks_per_group);
 756                 goto failed_mount;
 757         }
 758         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 759                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
 760                         sbi->s_frags_per_group);
 761                 goto failed_mount;
 762         }
 763         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
 764                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
 765                         sbi->s_inodes_per_group);
 766                 goto failed_mount;
 767         }
 768
 769         sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) -
 770                                         le32_to_cpu(es->s_first_data_block) +
 771                                        EXT2_BLOCKS_PER_GROUP(sb) - 1) /
 772                                        EXT2_BLOCKS_PER_GROUP(sb);
 773         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
 774                    EXT2_DESC_PER_BLOCK(sb);
 775         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
 776         if (sbi->s_group_desc == NULL) {
 777                 printk ("EXT2-fs: not enough memory\n");
 778                 goto failed_mount;
 779         }
 780         percpu_counter_init(&sbi->s_freeblocks_counter);
 781         percpu_counter_init(&sbi->s_freeinodes_counter);
 782         percpu_counter_init(&sbi->s_dirs_counter);
 783         bgl_lock_init(&sbi->s_blockgroup_lock);
 784         sbi->s_debts = kmalloc(sbi->s_groups_count * sizeof(*sbi->s_debts),
 785                                GFP_KERNEL);
 786         if (!sbi->s_debts) {
 787                 printk ("EXT2-fs: not enough memory\n");
 788                 goto failed_mount_group_desc;
 789         }
 790         memset(sbi->s_debts, 0, sbi->s_groups_count * sizeof(*sbi->s_debts));
 791         for (i = 0; i < db_count; i++) {
 792                 block = descriptor_loc(sb, logic_sb_block, i);
 793                 sbi->s_group_desc[i] = sb_bread(sb, block);
 794                 if (!sbi->s_group_desc[i]) {
 795                         for (j = 0; j < i; j++)
 796                                 brelse (sbi->s_group_desc[j]);
 797                         printk ("EXT2-fs: unable to read group descriptors\n");
 798                         goto failed_mount_group_desc;
 799                 }
 800         }
 801         if (!ext2_check_descriptors (sb)) {
 802                 printk ("EXT2-fs: group descriptors corrupted!\n");
 803                 db_count = i;
 804                 goto failed_mount2;
 805         }
 806         sbi->s_gdb_count = db_count;
 807         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
 808         spin_lock_init(&sbi->s_next_gen_lock);
 809         /*
 810          * set up enough so that it can read an inode
 811          */
 812         sb->s_op = &ext2_sops;
 813         sb->s_export_op = &ext2_export_ops;
 814         sb->s_xattr = ext2_xattr_handlers;
 815         root = iget(sb, EXT2_ROOT_INO);
 816         sb->s_root = d_alloc_root(root);
 817         if (!sb->s_root) {
 818                 iput(root);
 819                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
 820                 goto failed_mount2;
 821         }
 822         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
 823                 dput(sb->s_root);
 824                 sb->s_root = NULL;
 825                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
 826                 goto failed_mount2;
 827         }
 828         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 829                 ext2_warning(sb, __FUNCTION__,
 830                         "mounting ext3 filesystem as ext2\n");
 831         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
 832         percpu_counter_mod(&sbi->s_freeblocks_counter,
 833                                 ext2_count_free_blocks(sb));
 834         percpu_counter_mod(&sbi->s_freeinodes_counter,
 835                                 ext2_count_free_inodes(sb));
 836         percpu_counter_mod(&sbi->s_dirs_counter,
 837                                 ext2_count_dirs(sb));
 838         return 0;
 839 failed_mount2:
 840         for (i = 0; i < db_count; i++)
 841                 brelse(sbi->s_group_desc[i]);
 842 failed_mount_group_desc:
 843         kfree(sbi->s_group_desc);
 844         if (sbi->s_debts)
 845                 kfree(sbi->s_debts);
 846 failed_mount:
 847         brelse(bh);
 848 failed_sbi:
 849         sb->s_fs_info = NULL;
 850         kfree(sbi);
 851         return -EINVAL;
 852 }
 853
 854 static void ext2_commit_super (struct super_block * sb,
 855                                struct ext2_super_block * es)
 856 {
 857         es->s_wtime = cpu_to_le32(get_seconds());
 858         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 859         sb->s_dirt = 0;
 860 }
 861
 862 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
 863 {
 864         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 865         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 866         es->s_wtime = cpu_to_le32(get_seconds());
 867         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 868         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
 869         sb->s_dirt = 0;
 870 }
 871
 872 /*
 873  * In the second extended file system, it is not necessary to
 874  * write the super block since we use a mapping of the
 875  * disk super block in a buffer.
 876  *
 877  * However, this function is still used to set the fs valid
 878  * flags to 0.  We need to set this flag to 0 since the fs
 879  * may have been checked while mounted and e2fsck may have
 880  * set s_state to EXT2_VALID_FS after some corrections.
 881  */
 882
 883 void ext2_write_super (struct super_block * sb)
 884 {
 885         struct ext2_super_block * es;
 886         lock_kernel();
 887         if (!(sb->s_flags & MS_RDONLY)) {
 888                 es = EXT2_SB(sb)->s_es;
 889
 890                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
 891                         ext2_debug ("setting valid to 0\n");
 892                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
 893                                                   ~EXT2_VALID_FS);
 894                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 895                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 896                         es->s_mtime = cpu_to_le32(get_seconds());
 897                         ext2_sync_super(sb, es);
 898                 } else
 899                         ext2_commit_super (sb, es);
 900         }
 901         sb->s_dirt = 0;
 902         unlock_kernel();
 903 }
 904
 905 static int ext2_remount (struct super_block * sb, int * flags, char * data)
 906 {
 907         struct ext2_sb_info * sbi = EXT2_SB(sb);
 908         struct ext2_super_block * es;
 909
 910         /*
 911          * Allow the "check" option to be passed as a remount option.
 912          */
 913         if (!parse_options (data, sbi))
 914                 return -EINVAL;
 915
 916         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 917                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
 918
 919         es = sbi->s_es;
 920         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 921                 return 0;
 922         if (*flags & MS_RDONLY) {
 923                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
 924                     !(sbi->s_mount_state & EXT2_VALID_FS))
 925                         return 0;
 926                 /*
 927                  * OK, we are remounting a valid rw partition rdonly, so set
 928                  * the rdonly flag and then mark the partition as valid again.
 929                  */
 930                 es->s_state = cpu_to_le16(sbi->s_mount_state);
 931                 es->s_mtime = cpu_to_le32(get_seconds());
 932         } else {
 933                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
 934                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
 935                 if (ret) {
 936                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
 937                                "unsupported optional features (%x).\n",
 938                                sb->s_id, le32_to_cpu(ret));
 939                         return -EROFS;
 940                 }
 941                 /*
 942                  * Mounting a RDONLY partition read-write, so reread and
 943                  * store the current valid flag.  (It may have been changed
 944                  * by e2fsck since we originally mounted the partition.)
 945                  */
 946                 sbi->s_mount_state = le16_to_cpu(es->s_state);
 947                 if (!ext2_setup_super (sb, es, 0))
 948                         sb->s_flags &= ~MS_RDONLY;
 949         }
 950         ext2_sync_super(sb, es);
 951         return 0;
 952 }
 953
 954 static int ext2_statfs (struct super_block * sb, struct kstatfs * buf)
 955 {
 956         struct ext2_sb_info *sbi = EXT2_SB(sb);
 957         unsigned long overhead;
 958         int i;
 959
 960         if (test_opt (sb, MINIX_DF))
 961                 overhead = 0;
 962         else {
 963                 /*
 964                  * Compute the overhead (FS structures)
 965                  */
 966
 967                 /*
 968                  * All of the blocks before first_data_block are
 969                  * overhead
 970                  */
 971                 overhead = le32_to_cpu(sbi->s_es->s_first_data_block);
 972
 973                 /*
 974                  * Add the overhead attributed to the superblock and
 975                  * block group descriptors.  If the sparse superblocks
 976                  * feature is turned on, then not all groups have this.
 977                  */
 978                 for (i = 0; i < sbi->s_groups_count; i++)
 979                         overhead += ext2_bg_has_super(sb, i) +
 980                                 ext2_bg_num_gdb(sb, i);
 981
 982                 /*
 983                  * Every block group has an inode bitmap, a block
 984                  * bitmap, and an inode table.
 985                  */
 986                 overhead += (sbi->s_groups_count *
 987                              (2 + sbi->s_itb_per_group));
 988         }
 989
 990         buf->f_type = EXT2_SUPER_MAGIC;
 991         buf->f_bsize = sb->s_blocksize;
 992         buf->f_blocks = le32_to_cpu(sbi->s_es->s_blocks_count) - overhead;
 993         buf->f_bfree = ext2_count_free_blocks(sb);
 994         buf->f_bavail = buf->f_bfree - le32_to_cpu(sbi->s_es->s_r_blocks_count);
 995         if (buf->f_bfree < le32_to_cpu(sbi->s_es->s_r_blocks_count))
 996                 buf->f_bavail = 0;
 997         buf->f_files = le32_to_cpu(sbi->s_es->s_inodes_count);
 998         buf->f_ffree = ext2_count_free_inodes (sb);
 999         buf->f_namelen = EXT2_NAME_LEN;
1000         return 0;
1001 }
1002
1003 static struct super_block *ext2_get_sb(struct file_system_type *fs_type,
1004         int flags, const char *dev_name, void *data)
1005 {
1006         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1007 }
1008
1009 static struct file_system_type ext2_fs_type = {
1010         .owner          = THIS_MODULE,
1011         .name           = "ext2",
1012         .get_sb         = ext2_get_sb,
1013         .kill_sb        = kill_block_super,
1014         .fs_flags       = FS_REQUIRES_DEV,
1015 };
1016
1017 static int __init init_ext2_fs(void)
1018 {
1019         int err = init_ext2_xattr();
1020         if (err)
1021                 return err;
1022         err = init_inodecache();
1023         if (err)
1024                 goto out1;
1025         err = register_filesystem(&ext2_fs_type);
1026         if (err)
1027                 goto out;
1028         return 0;
1029 out:
1030         destroy_inodecache();
1031 out1:
1032         exit_ext2_xattr();
1033         return err;
1034 }
1035
1036 static void __exit exit_ext2_fs(void)
1037 {
1038         unregister_filesystem(&ext2_fs_type);
1039         destroy_inodecache();
1040         exit_ext2_xattr();
1041 }
1042
1043 module_init(init_ext2_fs)
1044 module_exit(exit_ext2_fs)