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 static void ext2_clear_inode(struct inode *inode)
 188 {
 189 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 190         struct ext2_inode_info *ei = EXT2_I(inode);
 191
 192         if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
 193                 posix_acl_release(ei->i_acl);
 194                 ei->i_acl = EXT2_ACL_NOT_CACHED;
 195         }
 196         if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
 197                 posix_acl_release(ei->i_default_acl);
 198                 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 199         }
 200 #endif
 201         if (!is_bad_inode(inode))
 202                 ext2_discard_prealloc(inode);
 203 }
 204
 205
 206 static struct super_operations ext2_sops = {
 207         .alloc_inode    = ext2_alloc_inode,
 208         .destroy_inode  = ext2_destroy_inode,
 209         .read_inode     = ext2_read_inode,
 210         .write_inode    = ext2_write_inode,
 211         .delete_inode   = ext2_delete_inode,
 212         .put_super      = ext2_put_super,
 213         .write_super    = ext2_write_super,
 214         .statfs         = ext2_statfs,
 215         .remount_fs     = ext2_remount,
 216         .clear_inode    = ext2_clear_inode,
 217 };
 218
 219 /* Yes, most of these are left as NULL!!
 220  * A NULL value implies the default, which works with ext2-like file
 221  * systems, but can be improved upon.
 222  * Currently only get_parent is required.
 223  */
 224 struct dentry *ext2_get_parent(struct dentry *child);
 225 static struct export_operations ext2_export_ops = {
 226         .get_parent = ext2_get_parent,
 227 };
 228
 229 static unsigned long get_sb_block(void **data)
 230 {
 231         unsigned long   sb_block;
 232         char            *options = (char *) *data;
 233
 234         if (!options || strncmp(options, "sb=", 3) != 0)
 235                 return 1;       /* Default location */
 236         options += 3;
 237         sb_block = simple_strtoul(options, &options, 0);
 238         if (*options && *options != ',') {
 239                 printk("EXT2-fs: Invalid sb specification: %s\n",
 240                        (char *) *data);
 241                 return 1;
 242         }
 243         if (*options == ',')
 244                 options++;
 245         *data = (void *) options;
 246         return sb_block;
 247 }
 248
 249 enum {
 250         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
 251         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
 252         Opt_nouid32, Opt_check, Opt_nocheck, Opt_debug, Opt_oldalloc, Opt_orlov, Opt_nobh,
 253         Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
 254         Opt_ignore, Opt_err,
 255 };
 256
 257 static match_table_t tokens = {
 258         {Opt_bsd_df, "bsddf"},
 259         {Opt_minix_df, "minixdf"},
 260         {Opt_grpid, "grpid"},
 261         {Opt_grpid, "bsdgroups"},
 262         {Opt_nogrpid, "nogrpid"},
 263         {Opt_nogrpid, "sysvgroups"},
 264         {Opt_resgid, "resgid=%u"},
 265         {Opt_resuid, "resuid=%u"},
 266         {Opt_sb, "sb=%u"},
 267         {Opt_err_cont, "errors=continue"},
 268         {Opt_err_panic, "errors=panic"},
 269         {Opt_err_ro, "errors=remount-ro"},
 270         {Opt_nouid32, "nouid32"},
 271         {Opt_nocheck, "check=none"},
 272         {Opt_nocheck, "nocheck"},
 273         {Opt_check, "check"},
 274         {Opt_debug, "debug"},
 275         {Opt_oldalloc, "oldalloc"},
 276         {Opt_orlov, "orlov"},
 277         {Opt_nobh, "nobh"},
 278         {Opt_user_xattr, "user_xattr"},
 279         {Opt_nouser_xattr, "nouser_xattr"},
 280         {Opt_acl, "acl"},
 281         {Opt_noacl, "noacl"},
 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                 case Opt_check:
 346 #ifdef CONFIG_EXT2_CHECK
 347                         set_opt (sbi->s_mount_opt, CHECK);
 348 #else
 349                         printk("EXT2 Check option not supported\n");
 350 #endif
 351                         break;
 352                 case Opt_nocheck:
 353                         clear_opt (sbi->s_mount_opt, CHECK);
 354                         break;
 355                 case Opt_debug:
 356                         set_opt (sbi->s_mount_opt, DEBUG);
 357                         break;
 358                 case Opt_oldalloc:
 359                         set_opt (sbi->s_mount_opt, OLDALLOC);
 360                         break;
 361                 case Opt_orlov:
 362                         clear_opt (sbi->s_mount_opt, OLDALLOC);
 363                         break;
 364                 case Opt_nobh:
 365                         set_opt (sbi->s_mount_opt, NOBH);
 366                         break;
 367 #ifdef CONFIG_EXT2_FS_XATTR
 368                 case Opt_user_xattr:
 369                         set_opt (sbi->s_mount_opt, XATTR_USER);
 370                         break;
 371                 case Opt_nouser_xattr:
 372                         clear_opt (sbi->s_mount_opt, XATTR_USER);
 373                         break;
 374 #else
 375                 case Opt_user_xattr:
 376                 case Opt_nouser_xattr:
 377                         printk("EXT2 (no)user_xattr options not supported\n");
 378                         break;
 379 #endif
 380 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 381                 case Opt_acl:
 382                         set_opt(sbi->s_mount_opt, POSIX_ACL);
 383                         break;
 384                 case Opt_noacl:
 385                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
 386                         break;
 387 #else
 388                 case Opt_acl:
 389                 case Opt_noacl:
 390                         printk("EXT2 (no)acl options not supported\n");
 391                         break;
 392 #endif
 393                 case Opt_ignore:
 394                         break;
 395                 default:
 396                         return 0;
 397                 }
 398         }
 399         sbi->s_mount_opt |= kind;
 400         return 1;
 401 }
 402
 403 static int ext2_setup_super (struct super_block * sb,
 404                               struct ext2_super_block * es,
 405                               int read_only)
 406 {
 407         int res = 0;
 408         struct ext2_sb_info *sbi = EXT2_SB(sb);
 409
 410         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 411                 printk ("EXT2-fs warning: revision level too high, "
 412                         "forcing read-only mode\n");
 413                 res = MS_RDONLY;
 414         }
 415         if (read_only)
 416                 return res;
 417         if (!(sbi->s_mount_state & EXT2_VALID_FS))
 418                 printk ("EXT2-fs warning: mounting unchecked fs, "
 419                         "running e2fsck is recommended\n");
 420         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 421                 printk ("EXT2-fs warning: mounting fs with errors, "
 422                         "running e2fsck is recommended\n");
 423         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 424                  le16_to_cpu(es->s_mnt_count) >=
 425                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 426                 printk ("EXT2-fs warning: maximal mount count reached, "
 427                         "running e2fsck is recommended\n");
 428         else if (le32_to_cpu(es->s_checkinterval) &&
 429                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 430                 printk ("EXT2-fs warning: checktime reached, "
 431                         "running e2fsck is recommended\n");
 432         if (!le16_to_cpu(es->s_max_mnt_count))
 433                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 434         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
 435         ext2_write_super(sb);
 436         if (test_opt (sb, DEBUG))
 437                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
 438                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
 439                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 440                         sbi->s_frag_size,
 441                         sbi->s_groups_count,
 442                         EXT2_BLOCKS_PER_GROUP(sb),
 443                         EXT2_INODES_PER_GROUP(sb),
 444                         sbi->s_mount_opt);
 445 #ifdef CONFIG_EXT2_CHECK
 446         if (test_opt (sb, CHECK)) {
 447                 ext2_check_blocks_bitmap (sb);
 448                 ext2_check_inodes_bitmap (sb);
 449         }
 450 #endif
 451         return res;
 452 }
 453
 454 static int ext2_check_descriptors (struct super_block * sb)
 455 {
 456         int i;
 457         int desc_block = 0;
 458         struct ext2_sb_info *sbi = EXT2_SB(sb);
 459         unsigned long block = le32_to_cpu(sbi->s_es->s_first_data_block);
 460         struct ext2_group_desc * gdp = NULL;
 461
 462         ext2_debug ("Checking group descriptors");
 463
 464         for (i = 0; i < sbi->s_groups_count; i++)
 465         {
 466                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
 467                         gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
 468                 if (le32_to_cpu(gdp->bg_block_bitmap) < block ||
 469                     le32_to_cpu(gdp->bg_block_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 470                 {
 471                         ext2_error (sb, "ext2_check_descriptors",
 472                                     "Block bitmap for group %d"
 473                                     " not in group (block %lu)!",
 474                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 475                         return 0;
 476                 }
 477                 if (le32_to_cpu(gdp->bg_inode_bitmap) < block ||
 478                     le32_to_cpu(gdp->bg_inode_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 479                 {
 480                         ext2_error (sb, "ext2_check_descriptors",
 481                                     "Inode bitmap for group %d"
 482                                     " not in group (block %lu)!",
 483                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 484                         return 0;
 485                 }
 486                 if (le32_to_cpu(gdp->bg_inode_table) < block ||
 487                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >=
 488                     block + EXT2_BLOCKS_PER_GROUP(sb))
 489                 {
 490                         ext2_error (sb, "ext2_check_descriptors",
 491                                     "Inode table for group %d"
 492                                     " not in group (block %lu)!",
 493                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 494                         return 0;
 495                 }
 496                 block += EXT2_BLOCKS_PER_GROUP(sb);
 497                 gdp++;
 498         }
 499         return 1;
 500 }
 501
 502 #define log2(n) ffz(~(n))
 503
 504 /*
 505  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 506  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 507  * We need to be 1 filesystem block less than the 2^32 sector limit.
 508  */
 509 static loff_t ext2_max_size(int bits)
 510 {
 511         loff_t res = EXT2_NDIR_BLOCKS;
 512         res += 1LL << (bits-2);
 513         res += 1LL << (2*(bits-2));
 514         res += 1LL << (3*(bits-2));
 515         res <<= bits;
 516         if (res > (512LL << 32) - (1 << bits))
 517                 res = (512LL << 32) - (1 << bits);
 518         return res;
 519 }
 520
 521 static unsigned long descriptor_loc(struct super_block *sb,
 522                                     unsigned long logic_sb_block,
 523                                     int nr)
 524 {
 525         struct ext2_sb_info *sbi = EXT2_SB(sb);
 526         unsigned long bg, first_data_block, first_meta_bg;
 527         int has_super = 0;
 528
 529         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 530         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 531
 532         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 533             nr < first_meta_bg)
 534                 return (logic_sb_block + nr + 1);
 535         bg = sbi->s_desc_per_block * nr;
 536         if (ext2_bg_has_super(sb, bg))
 537                 has_super = 1;
 538         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
 539 }
 540
 541 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 542 {
 543         struct buffer_head * bh;
 544         struct ext2_sb_info * sbi;
 545         struct ext2_super_block * es;
 546         struct inode *root;
 547         unsigned long block;
 548         unsigned long sb_block = get_sb_block(&data);
 549         unsigned long logic_sb_block;
 550         unsigned long offset = 0;
 551         unsigned long def_mount_opts;
 552         int blocksize = BLOCK_SIZE;
 553         int db_count;
 554         int i, j;
 555         __le32 features;
 556
 557         sbi = kmalloc(sizeof(*sbi), GFP_KERNEL);
 558         if (!sbi)
 559                 return -ENOMEM;
 560         sb->s_fs_info = sbi;
 561         memset(sbi, 0, sizeof(*sbi));
 562
 563         /*
 564          * See what the current blocksize for the device is, and
 565          * use that as the blocksize.  Otherwise (or if the blocksize
 566          * is smaller than the default) use the default.
 567          * This is important for devices that have a hardware
 568          * sectorsize that is larger than the default.
 569          */
 570         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 571         if (!blocksize) {
 572                 printk ("EXT2-fs: unable to set blocksize\n");
 573                 goto failed_sbi;
 574         }
 575
 576         /*
 577          * If the superblock doesn't start on a hardware sector boundary,
 578          * calculate the offset.
 579          */
 580         if (blocksize != BLOCK_SIZE) {
 581                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 582                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 583         } else {
 584                 logic_sb_block = sb_block;
 585         }
 586
 587         if (!(bh = sb_bread(sb, logic_sb_block))) {
 588                 printk ("EXT2-fs: unable to read superblock\n");
 589                 goto failed_sbi;
 590         }
 591         /*
 592          * Note: s_es must be initialized as soon as possible because
 593          *       some ext2 macro-instructions depend on its value
 594          */
 595         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 596         sbi->s_es = es;
 597         sb->s_magic = le16_to_cpu(es->s_magic);
 598         sb->s_flags |= MS_ONE_SECOND;
 599
 600         if (sb->s_magic != EXT2_SUPER_MAGIC)
 601                 goto cantfind_ext2;
 602
 603         /* Set defaults before we parse the mount options */
 604         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 605         if (def_mount_opts & EXT2_DEFM_DEBUG)
 606                 set_opt(sbi->s_mount_opt, DEBUG);
 607         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 608                 set_opt(sbi->s_mount_opt, GRPID);
 609         if (def_mount_opts & EXT2_DEFM_UID16)
 610                 set_opt(sbi->s_mount_opt, NO_UID32);
 611         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 612                 set_opt(sbi->s_mount_opt, XATTR_USER);
 613         if (def_mount_opts & EXT2_DEFM_ACL)
 614                 set_opt(sbi->s_mount_opt, POSIX_ACL);
 615
 616         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 617                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 618         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
 619                 set_opt(sbi->s_mount_opt, ERRORS_RO);
 620
 621         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
 622         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
 623
 624         if (!parse_options ((char *) data, sbi))
 625                 goto failed_mount;
 626
 627         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 628                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 629                  MS_POSIXACL : 0);
 630
 631         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 632             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 633              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 634              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 635                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
 636                        "running e2fsck is recommended\n");
 637         /*
 638          * Check feature flags regardless of the revision level, since we
 639          * previously didn't change the revision level when setting the flags,
 640          * so there is a chance incompat flags are set on a rev 0 filesystem.
 641          */
 642         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 643         if (features) {
 644                 printk("EXT2-fs: %s: couldn't mount because of "
 645                        "unsupported optional features (%x).\n",
 646                        sb->s_id, le32_to_cpu(features));
 647                 goto failed_mount;
 648         }
 649         if (!(sb->s_flags & MS_RDONLY) &&
 650             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 651                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
 652                        "unsupported optional features (%x).\n",
 653                        sb->s_id, le32_to_cpu(features));
 654                 goto failed_mount;
 655         }
 656
 657         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 658
 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
 701         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 702                                    le32_to_cpu(es->s_log_frag_size);
 703         if (sbi->s_frag_size == 0)
 704                 goto cantfind_ext2;
 705         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
 706
 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
 711         if (EXT2_INODE_SIZE(sb) == 0)
 712                 goto cantfind_ext2;
 713         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
 714         if (sbi->s_inodes_per_block == 0)
 715                 goto cantfind_ext2;
 716         sbi->s_itb_per_group = sbi->s_inodes_per_group /
 717                                         sbi->s_inodes_per_block;
 718         sbi->s_desc_per_block = sb->s_blocksize /
 719                                         sizeof (struct ext2_group_desc);
 720         sbi->s_sbh = bh;
 721         sbi->s_mount_state = le16_to_cpu(es->s_state);
 722         sbi->s_addr_per_block_bits =
 723                 log2 (EXT2_ADDR_PER_BLOCK(sb));
 724         sbi->s_desc_per_block_bits =
 725                 log2 (EXT2_DESC_PER_BLOCK(sb));
 726
 727         if (sb->s_magic != EXT2_SUPER_MAGIC)
 728                 goto cantfind_ext2;
 729
 730         if (sb->s_blocksize != bh->b_size) {
 731                 if (!silent)
 732                         printk ("VFS: Unsupported blocksize on dev "
 733                                 "%s.\n", sb->s_id);
 734                 goto failed_mount;
 735         }
 736
 737         if (sb->s_blocksize != sbi->s_frag_size) {
 738                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
 739                         sbi->s_frag_size, sb->s_blocksize);
 740                 goto failed_mount;
 741         }
 742
 743         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
 744                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
 745                         sbi->s_blocks_per_group);
 746                 goto failed_mount;
 747         }
 748         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 749                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
 750                         sbi->s_frags_per_group);
 751                 goto failed_mount;
 752         }
 753         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
 754                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
 755                         sbi->s_inodes_per_group);
 756                 goto failed_mount;
 757         }
 758
 759         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
 760                 goto cantfind_ext2;
 761         sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) -
 762                                         le32_to_cpu(es->s_first_data_block) +
 763                                        EXT2_BLOCKS_PER_GROUP(sb) - 1) /
 764                                        EXT2_BLOCKS_PER_GROUP(sb);
 765         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
 766                    EXT2_DESC_PER_BLOCK(sb);
 767         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
 768         if (sbi->s_group_desc == NULL) {
 769                 printk ("EXT2-fs: not enough memory\n");
 770                 goto failed_mount;
 771         }
 772         percpu_counter_init(&sbi->s_freeblocks_counter);
 773         percpu_counter_init(&sbi->s_freeinodes_counter);
 774         percpu_counter_init(&sbi->s_dirs_counter);
 775         bgl_lock_init(&sbi->s_blockgroup_lock);
 776         sbi->s_debts = kmalloc(sbi->s_groups_count * sizeof(*sbi->s_debts),
 777                                GFP_KERNEL);
 778         if (!sbi->s_debts) {
 779                 printk ("EXT2-fs: not enough memory\n");
 780                 goto failed_mount_group_desc;
 781         }
 782         memset(sbi->s_debts, 0, sbi->s_groups_count * sizeof(*sbi->s_debts));
 783         for (i = 0; i < db_count; i++) {
 784                 block = descriptor_loc(sb, logic_sb_block, i);
 785                 sbi->s_group_desc[i] = sb_bread(sb, block);
 786                 if (!sbi->s_group_desc[i]) {
 787                         for (j = 0; j < i; j++)
 788                                 brelse (sbi->s_group_desc[j]);
 789                         printk ("EXT2-fs: unable to read group descriptors\n");
 790                         goto failed_mount_group_desc;
 791                 }
 792         }
 793         if (!ext2_check_descriptors (sb)) {
 794                 printk ("EXT2-fs: group descriptors corrupted!\n");
 795                 db_count = i;
 796                 goto failed_mount2;
 797         }
 798         sbi->s_gdb_count = db_count;
 799         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
 800         spin_lock_init(&sbi->s_next_gen_lock);
 801         /*
 802          * set up enough so that it can read an inode
 803          */
 804         sb->s_op = &ext2_sops;
 805         sb->s_export_op = &ext2_export_ops;
 806         sb->s_xattr = ext2_xattr_handlers;
 807         root = iget(sb, EXT2_ROOT_INO);
 808         sb->s_root = d_alloc_root(root);
 809         if (!sb->s_root) {
 810                 iput(root);
 811                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
 812                 goto failed_mount2;
 813         }
 814         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
 815                 dput(sb->s_root);
 816                 sb->s_root = NULL;
 817                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
 818                 goto failed_mount2;
 819         }
 820         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 821                 ext2_warning(sb, __FUNCTION__,
 822                         "mounting ext3 filesystem as ext2\n");
 823         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
 824         percpu_counter_mod(&sbi->s_freeblocks_counter,
 825                                 ext2_count_free_blocks(sb));
 826         percpu_counter_mod(&sbi->s_freeinodes_counter,
 827                                 ext2_count_free_inodes(sb));
 828         percpu_counter_mod(&sbi->s_dirs_counter,
 829                                 ext2_count_dirs(sb));
 830         return 0;
 831
 832 cantfind_ext2:
 833         if (!silent)
 834                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
 835                        sb->s_id);
 836         goto failed_mount;
 837
 838 failed_mount2:
 839         for (i = 0; i < db_count; i++)
 840                 brelse(sbi->s_group_desc[i]);
 841 failed_mount_group_desc:
 842         kfree(sbi->s_group_desc);
 843         kfree(sbi->s_debts);
 844 failed_mount:
 845         brelse(bh);
 846 failed_sbi:
 847         sb->s_fs_info = NULL;
 848         kfree(sbi);
 849         return -EINVAL;
 850 }
 851
 852 static void ext2_commit_super (struct super_block * sb,
 853                                struct ext2_super_block * es)
 854 {
 855         es->s_wtime = cpu_to_le32(get_seconds());
 856         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 857         sb->s_dirt = 0;
 858 }
 859
 860 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
 861 {
 862         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 863         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 864         es->s_wtime = cpu_to_le32(get_seconds());
 865         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 866         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
 867         sb->s_dirt = 0;
 868 }
 869
 870 /*
 871  * In the second extended file system, it is not necessary to
 872  * write the super block since we use a mapping of the
 873  * disk super block in a buffer.
 874  *
 875  * However, this function is still used to set the fs valid
 876  * flags to 0.  We need to set this flag to 0 since the fs
 877  * may have been checked while mounted and e2fsck may have
 878  * set s_state to EXT2_VALID_FS after some corrections.
 879  */
 880
 881 void ext2_write_super (struct super_block * sb)
 882 {
 883         struct ext2_super_block * es;
 884         lock_kernel();
 885         if (!(sb->s_flags & MS_RDONLY)) {
 886                 es = EXT2_SB(sb)->s_es;
 887
 888                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
 889                         ext2_debug ("setting valid to 0\n");
 890                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
 891                                                   ~EXT2_VALID_FS);
 892                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 893                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 894                         es->s_mtime = cpu_to_le32(get_seconds());
 895                         ext2_sync_super(sb, es);
 896                 } else
 897                         ext2_commit_super (sb, es);
 898         }
 899         sb->s_dirt = 0;
 900         unlock_kernel();
 901 }
 902
 903 static int ext2_remount (struct super_block * sb, int * flags, char * data)
 904 {
 905         struct ext2_sb_info * sbi = EXT2_SB(sb);
 906         struct ext2_super_block * es;
 907
 908         /*
 909          * Allow the "check" option to be passed as a remount option.
 910          */
 911         if (!parse_options (data, sbi))
 912                 return -EINVAL;
 913
 914         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 915                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
 916
 917         es = sbi->s_es;
 918         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 919                 return 0;
 920         if (*flags & MS_RDONLY) {
 921                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
 922                     !(sbi->s_mount_state & EXT2_VALID_FS))
 923                         return 0;
 924                 /*
 925                  * OK, we are remounting a valid rw partition rdonly, so set
 926                  * the rdonly flag and then mark the partition as valid again.
 927                  */
 928                 es->s_state = cpu_to_le16(sbi->s_mount_state);
 929                 es->s_mtime = cpu_to_le32(get_seconds());
 930         } else {
 931                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
 932                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
 933                 if (ret) {
 934                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
 935                                "unsupported optional features (%x).\n",
 936                                sb->s_id, le32_to_cpu(ret));
 937                         return -EROFS;
 938                 }
 939                 /*
 940                  * Mounting a RDONLY partition read-write, so reread and
 941                  * store the current valid flag.  (It may have been changed
 942                  * by e2fsck since we originally mounted the partition.)
 943                  */
 944                 sbi->s_mount_state = le16_to_cpu(es->s_state);
 945                 if (!ext2_setup_super (sb, es, 0))
 946                         sb->s_flags &= ~MS_RDONLY;
 947         }
 948         ext2_sync_super(sb, es);
 949         return 0;
 950 }
 951
 952 static int ext2_statfs (struct super_block * sb, struct kstatfs * buf)
 953 {
 954         struct ext2_sb_info *sbi = EXT2_SB(sb);
 955         unsigned long overhead;
 956         int i;
 957
 958         if (test_opt (sb, MINIX_DF))
 959                 overhead = 0;
 960         else {
 961                 /*
 962                  * Compute the overhead (FS structures)
 963                  */
 964
 965                 /*
 966                  * All of the blocks before first_data_block are
 967                  * overhead
 968                  */
 969                 overhead = le32_to_cpu(sbi->s_es->s_first_data_block);
 970
 971                 /*
 972                  * Add the overhead attributed to the superblock and
 973                  * block group descriptors.  If the sparse superblocks
 974                  * feature is turned on, then not all groups have this.
 975                  */
 976                 for (i = 0; i < sbi->s_groups_count; i++)
 977                         overhead += ext2_bg_has_super(sb, i) +
 978                                 ext2_bg_num_gdb(sb, i);
 979
 980                 /*
 981                  * Every block group has an inode bitmap, a block
 982                  * bitmap, and an inode table.
 983                  */
 984                 overhead += (sbi->s_groups_count *
 985                              (2 + sbi->s_itb_per_group));
 986         }
 987
 988         buf->f_type = EXT2_SUPER_MAGIC;
 989         buf->f_bsize = sb->s_blocksize;
 990         buf->f_blocks = le32_to_cpu(sbi->s_es->s_blocks_count) - overhead;
 991         buf->f_bfree = ext2_count_free_blocks(sb);
 992         buf->f_bavail = buf->f_bfree - le32_to_cpu(sbi->s_es->s_r_blocks_count);
 993         if (buf->f_bfree < le32_to_cpu(sbi->s_es->s_r_blocks_count))
 994                 buf->f_bavail = 0;
 995         buf->f_files = le32_to_cpu(sbi->s_es->s_inodes_count);
 996         buf->f_ffree = ext2_count_free_inodes (sb);
 997         buf->f_namelen = EXT2_NAME_LEN;
 998         return 0;
 999 }
1000
1001 static struct super_block *ext2_get_sb(struct file_system_type *fs_type,
1002         int flags, const char *dev_name, void *data)
1003 {
1004         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1005 }
1006
1007 static struct file_system_type ext2_fs_type = {
1008         .owner          = THIS_MODULE,
1009         .name           = "ext2",
1010         .get_sb         = ext2_get_sb,
1011         .kill_sb        = kill_block_super,
1012         .fs_flags       = FS_REQUIRES_DEV,
1013 };
1014
1015 static int __init init_ext2_fs(void)
1016 {
1017         int err = init_ext2_xattr();
1018         if (err)
1019                 return err;
1020         err = init_inodecache();
1021         if (err)
1022                 goto out1;
1023         err = register_filesystem(&ext2_fs_type);
1024         if (err)
1025                 goto out;
1026         return 0;
1027 out:
1028         destroy_inodecache();
1029 out1:
1030         exit_ext2_xattr();
1031         return err;
1032 }
1033
1034 static void __exit exit_ext2_fs(void)
1035 {
1036         unregister_filesystem(&ext2_fs_type);
1037         destroy_inodecache();
1038         exit_ext2_xattr();
1039 }
1040
1041 module_init(init_ext2_fs)
1042 module_exit(exit_ext2_fs)