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/module.h>
  20 #include <linux/string.h>
  21 #include <linux/fs.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/exportfs.h>
  29 #include <linux/smp_lock.h>
  30 #include <linux/vfs.h>
  31 #include <linux/seq_file.h>
  32 #include <linux/mount.h>
  33 #include <asm/uaccess.h>
  34 #include "ext2.h"
  35 #include "xattr.h"
  36 #include "acl.h"
  37 #include "xip.h"
  38
  39 static void ext2_sync_super(struct super_block *sb,
  40                             struct ext2_super_block *es);
  41 static int ext2_remount (struct super_block * sb, int * flags, char * data);
  42 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
  43
  44 void ext2_error (struct super_block * sb, const char * function,
  45                  const char * fmt, ...)
  46 {
  47         va_list args;
  48         struct ext2_sb_info *sbi = EXT2_SB(sb);
  49         struct ext2_super_block *es = sbi->s_es;
  50
  51         if (!(sb->s_flags & MS_RDONLY)) {
  52                 sbi->s_mount_state |= EXT2_ERROR_FS;
  53                 es->s_state =
  54                         cpu_to_le16(le16_to_cpu(es->s_state) | EXT2_ERROR_FS);
  55                 ext2_sync_super(sb, es);
  56         }
  57
  58         va_start(args, fmt);
  59         printk(KERN_CRIT "EXT2-fs error (device %s): %s: ",sb->s_id, function);
  60         vprintk(fmt, args);
  61         printk("\n");
  62         va_end(args);
  63
  64         if (test_opt(sb, ERRORS_PANIC))
  65                 panic("EXT2-fs panic from previous error\n");
  66         if (test_opt(sb, ERRORS_RO)) {
  67                 printk("Remounting filesystem read-only\n");
  68                 sb->s_flags |= MS_RDONLY;
  69         }
  70 }
  71
  72 void ext2_warning (struct super_block * sb, const char * function,
  73                    const char * fmt, ...)
  74 {
  75         va_list args;
  76
  77         va_start(args, fmt);
  78         printk(KERN_WARNING "EXT2-fs warning (device %s): %s: ",
  79                sb->s_id, function);
  80         vprintk(fmt, args);
  81         printk("\n");
  82         va_end(args);
  83 }
  84
  85 void ext2_update_dynamic_rev(struct super_block *sb)
  86 {
  87         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
  88
  89         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
  90                 return;
  91
  92         ext2_warning(sb, __FUNCTION__,
  93                      "updating to rev %d because of new feature flag, "
  94                      "running e2fsck is recommended",
  95                      EXT2_DYNAMIC_REV);
  96
  97         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
  98         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
  99         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
 100         /* leave es->s_feature_*compat flags alone */
 101         /* es->s_uuid will be set by e2fsck if empty */
 102
 103         /*
 104          * The rest of the superblock fields should be zero, and if not it
 105          * means they are likely already in use, so leave them alone.  We
 106          * can leave it up to e2fsck to clean up any inconsistencies there.
 107          */
 108 }
 109
 110 static void ext2_put_super (struct super_block * sb)
 111 {
 112         int db_count;
 113         int i;
 114         struct ext2_sb_info *sbi = EXT2_SB(sb);
 115
 116         ext2_xattr_put_super(sb);
 117         if (!(sb->s_flags & MS_RDONLY)) {
 118                 struct ext2_super_block *es = sbi->s_es;
 119
 120                 es->s_state = cpu_to_le16(sbi->s_mount_state);
 121                 ext2_sync_super(sb, es);
 122         }
 123         db_count = sbi->s_gdb_count;
 124         for (i = 0; i < db_count; i++)
 125                 if (sbi->s_group_desc[i])
 126                         brelse (sbi->s_group_desc[i]);
 127         kfree(sbi->s_group_desc);
 128         kfree(sbi->s_debts);
 129         percpu_counter_destroy(&sbi->s_freeblocks_counter);
 130         percpu_counter_destroy(&sbi->s_freeinodes_counter);
 131         percpu_counter_destroy(&sbi->s_dirs_counter);
 132         brelse (sbi->s_sbh);
 133         sb->s_fs_info = NULL;
 134         kfree(sbi);
 135
 136         return;
 137 }
 138
 139 static struct kmem_cache * ext2_inode_cachep;
 140
 141 static struct inode *ext2_alloc_inode(struct super_block *sb)
 142 {
 143         struct ext2_inode_info *ei;
 144         ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
 145         if (!ei)
 146                 return NULL;
 147 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 148         ei->i_acl = EXT2_ACL_NOT_CACHED;
 149         ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 150 #endif
 151         ei->vfs_inode.i_version = 1;
 152         return &ei->vfs_inode;
 153 }
 154
 155 static void ext2_destroy_inode(struct inode *inode)
 156 {
 157         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
 158 }
 159
 160 static void init_once(void * foo, struct kmem_cache * cachep, unsigned long flags)
 161 {
 162         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
 163
 164         rwlock_init(&ei->i_meta_lock);
 165 #ifdef CONFIG_EXT2_FS_XATTR
 166         init_rwsem(&ei->xattr_sem);
 167 #endif
 168         inode_init_once(&ei->vfs_inode);
 169 }
 170
 171 static int init_inodecache(void)
 172 {
 173         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
 174                                              sizeof(struct ext2_inode_info),
 175                                              0, (SLAB_RECLAIM_ACCOUNT|
 176                                                 SLAB_MEM_SPREAD),
 177                                              init_once, NULL);
 178         if (ext2_inode_cachep == NULL)
 179                 return -ENOMEM;
 180         return 0;
 181 }
 182
 183 static void destroy_inodecache(void)
 184 {
 185         kmem_cache_destroy(ext2_inode_cachep);
 186 }
 187
 188 static void ext2_clear_inode(struct inode *inode)
 189 {
 190 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 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 #endif
 202 }
 203
 204 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
 205 {
 206         struct ext2_sb_info *sbi = EXT2_SB(vfs->mnt_sb);
 207
 208         if (sbi->s_mount_opt & EXT2_MOUNT_GRPID)
 209                 seq_puts(seq, ",grpid");
 210
 211 #if defined(CONFIG_QUOTA)
 212         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
 213                 seq_puts(seq, ",usrquota");
 214
 215         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
 216                 seq_puts(seq, ",grpquota");
 217 #endif
 218
 219 #if defined(CONFIG_EXT2_FS_XIP)
 220         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
 221                 seq_puts(seq, ",xip");
 222 #endif
 223
 224         return 0;
 225 }
 226
 227 #ifdef CONFIG_QUOTA
 228 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
 229 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
 230 #endif
 231
 232 static const struct super_operations ext2_sops = {
 233         .alloc_inode    = ext2_alloc_inode,
 234         .destroy_inode  = ext2_destroy_inode,
 235         .read_inode     = ext2_read_inode,
 236         .write_inode    = ext2_write_inode,
 237         .put_inode      = ext2_put_inode,
 238         .delete_inode   = ext2_delete_inode,
 239         .put_super      = ext2_put_super,
 240         .write_super    = ext2_write_super,
 241         .statfs         = ext2_statfs,
 242         .remount_fs     = ext2_remount,
 243         .clear_inode    = ext2_clear_inode,
 244         .show_options   = ext2_show_options,
 245 #ifdef CONFIG_QUOTA
 246         .quota_read     = ext2_quota_read,
 247         .quota_write    = ext2_quota_write,
 248 #endif
 249 };
 250
 251 static struct dentry *ext2_get_dentry(struct super_block *sb, void *vobjp)
 252 {
 253         __u32 *objp = vobjp;
 254         unsigned long ino = objp[0];
 255         __u32 generation = objp[1];
 256         struct inode *inode;
 257         struct dentry *result;
 258
 259         if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
 260                 return ERR_PTR(-ESTALE);
 261         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
 262                 return ERR_PTR(-ESTALE);
 263
 264         /* iget isn't really right if the inode is currently unallocated!!
 265          * ext2_read_inode currently does appropriate checks, but
 266          * it might be "neater" to call ext2_get_inode first and check
 267          * if the inode is valid.....
 268          */
 269         inode = iget(sb, ino);
 270         if (inode == NULL)
 271                 return ERR_PTR(-ENOMEM);
 272         if (is_bad_inode(inode) ||
 273             (generation && inode->i_generation != generation)) {
 274                 /* we didn't find the right inode.. */
 275                 iput(inode);
 276                 return ERR_PTR(-ESTALE);
 277         }
 278         /* now to find a dentry.
 279          * If possible, get a well-connected one
 280          */
 281         result = d_alloc_anon(inode);
 282         if (!result) {
 283                 iput(inode);
 284                 return ERR_PTR(-ENOMEM);
 285         }
 286         return result;
 287 }
 288
 289 /* Yes, most of these are left as NULL!!
 290  * A NULL value implies the default, which works with ext2-like file
 291  * systems, but can be improved upon.
 292  * Currently only get_parent is required.
 293  */
 294 static struct export_operations ext2_export_ops = {
 295         .get_parent = ext2_get_parent,
 296         .get_dentry = ext2_get_dentry,
 297 };
 298
 299 static unsigned long get_sb_block(void **data)
 300 {
 301         unsigned long   sb_block;
 302         char            *options = (char *) *data;
 303
 304         if (!options || strncmp(options, "sb=", 3) != 0)
 305                 return 1;       /* Default location */
 306         options += 3;
 307         sb_block = simple_strtoul(options, &options, 0);
 308         if (*options && *options != ',') {
 309                 printk("EXT2-fs: Invalid sb specification: %s\n",
 310                        (char *) *data);
 311                 return 1;
 312         }
 313         if (*options == ',')
 314                 options++;
 315         *data = (void *) options;
 316         return sb_block;
 317 }
 318
 319 enum {
 320         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
 321         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
 322         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
 323         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
 324         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
 325         Opt_usrquota, Opt_grpquota
 326 };
 327
 328 static match_table_t tokens = {
 329         {Opt_bsd_df, "bsddf"},
 330         {Opt_minix_df, "minixdf"},
 331         {Opt_grpid, "grpid"},
 332         {Opt_grpid, "bsdgroups"},
 333         {Opt_nogrpid, "nogrpid"},
 334         {Opt_nogrpid, "sysvgroups"},
 335         {Opt_resgid, "resgid=%u"},
 336         {Opt_resuid, "resuid=%u"},
 337         {Opt_sb, "sb=%u"},
 338         {Opt_err_cont, "errors=continue"},
 339         {Opt_err_panic, "errors=panic"},
 340         {Opt_err_ro, "errors=remount-ro"},
 341         {Opt_nouid32, "nouid32"},
 342         {Opt_nocheck, "check=none"},
 343         {Opt_nocheck, "nocheck"},
 344         {Opt_debug, "debug"},
 345         {Opt_oldalloc, "oldalloc"},
 346         {Opt_orlov, "orlov"},
 347         {Opt_nobh, "nobh"},
 348         {Opt_user_xattr, "user_xattr"},
 349         {Opt_nouser_xattr, "nouser_xattr"},
 350         {Opt_acl, "acl"},
 351         {Opt_noacl, "noacl"},
 352         {Opt_xip, "xip"},
 353         {Opt_grpquota, "grpquota"},
 354         {Opt_ignore, "noquota"},
 355         {Opt_quota, "quota"},
 356         {Opt_usrquota, "usrquota"},
 357         {Opt_err, NULL}
 358 };
 359
 360 static int parse_options (char * options,
 361                           struct ext2_sb_info *sbi)
 362 {
 363         char * p;
 364         substring_t args[MAX_OPT_ARGS];
 365         int option;
 366
 367         if (!options)
 368                 return 1;
 369
 370         while ((p = strsep (&options, ",")) != NULL) {
 371                 int token;
 372                 if (!*p)
 373                         continue;
 374
 375                 token = match_token(p, tokens, args);
 376                 switch (token) {
 377                 case Opt_bsd_df:
 378                         clear_opt (sbi->s_mount_opt, MINIX_DF);
 379                         break;
 380                 case Opt_minix_df:
 381                         set_opt (sbi->s_mount_opt, MINIX_DF);
 382                         break;
 383                 case Opt_grpid:
 384                         set_opt (sbi->s_mount_opt, GRPID);
 385                         break;
 386                 case Opt_nogrpid:
 387                         clear_opt (sbi->s_mount_opt, GRPID);
 388                         break;
 389                 case Opt_resuid:
 390                         if (match_int(&args[0], &option))
 391                                 return 0;
 392                         sbi->s_resuid = option;
 393                         break;
 394                 case Opt_resgid:
 395                         if (match_int(&args[0], &option))
 396                                 return 0;
 397                         sbi->s_resgid = option;
 398                         break;
 399                 case Opt_sb:
 400                         /* handled by get_sb_block() instead of here */
 401                         /* *sb_block = match_int(&args[0]); */
 402                         break;
 403                 case Opt_err_panic:
 404                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 405                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
 406                         set_opt (sbi->s_mount_opt, ERRORS_PANIC);
 407                         break;
 408                 case Opt_err_ro:
 409                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 410                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 411                         set_opt (sbi->s_mount_opt, ERRORS_RO);
 412                         break;
 413                 case Opt_err_cont:
 414                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
 415                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 416                         set_opt (sbi->s_mount_opt, ERRORS_CONT);
 417                         break;
 418                 case Opt_nouid32:
 419                         set_opt (sbi->s_mount_opt, NO_UID32);
 420                         break;
 421                 case Opt_nocheck:
 422                         clear_opt (sbi->s_mount_opt, CHECK);
 423                         break;
 424                 case Opt_debug:
 425                         set_opt (sbi->s_mount_opt, DEBUG);
 426                         break;
 427                 case Opt_oldalloc:
 428                         set_opt (sbi->s_mount_opt, OLDALLOC);
 429                         break;
 430                 case Opt_orlov:
 431                         clear_opt (sbi->s_mount_opt, OLDALLOC);
 432                         break;
 433                 case Opt_nobh:
 434                         set_opt (sbi->s_mount_opt, NOBH);
 435                         break;
 436 #ifdef CONFIG_EXT2_FS_XATTR
 437                 case Opt_user_xattr:
 438                         set_opt (sbi->s_mount_opt, XATTR_USER);
 439                         break;
 440                 case Opt_nouser_xattr:
 441                         clear_opt (sbi->s_mount_opt, XATTR_USER);
 442                         break;
 443 #else
 444                 case Opt_user_xattr:
 445                 case Opt_nouser_xattr:
 446                         printk("EXT2 (no)user_xattr options not supported\n");
 447                         break;
 448 #endif
 449 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 450                 case Opt_acl:
 451                         set_opt(sbi->s_mount_opt, POSIX_ACL);
 452                         break;
 453                 case Opt_noacl:
 454                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
 455                         break;
 456 #else
 457                 case Opt_acl:
 458                 case Opt_noacl:
 459                         printk("EXT2 (no)acl options not supported\n");
 460                         break;
 461 #endif
 462                 case Opt_xip:
 463 #ifdef CONFIG_EXT2_FS_XIP
 464                         set_opt (sbi->s_mount_opt, XIP);
 465 #else
 466                         printk("EXT2 xip option not supported\n");
 467 #endif
 468                         break;
 469
 470 #if defined(CONFIG_QUOTA)
 471                 case Opt_quota:
 472                 case Opt_usrquota:
 473                         set_opt(sbi->s_mount_opt, USRQUOTA);
 474                         break;
 475
 476                 case Opt_grpquota:
 477                         set_opt(sbi->s_mount_opt, GRPQUOTA);
 478                         break;
 479 #else
 480                 case Opt_quota:
 481                 case Opt_usrquota:
 482                 case Opt_grpquota:
 483                         printk(KERN_ERR
 484                                 "EXT2-fs: quota operations not supported.\n");
 485
 486                         break;
 487 #endif
 488
 489                 case Opt_ignore:
 490                         break;
 491                 default:
 492                         return 0;
 493                 }
 494         }
 495         return 1;
 496 }
 497
 498 static int ext2_setup_super (struct super_block * sb,
 499                               struct ext2_super_block * es,
 500                               int read_only)
 501 {
 502         int res = 0;
 503         struct ext2_sb_info *sbi = EXT2_SB(sb);
 504
 505         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 506                 printk ("EXT2-fs warning: revision level too high, "
 507                         "forcing read-only mode\n");
 508                 res = MS_RDONLY;
 509         }
 510         if (read_only)
 511                 return res;
 512         if (!(sbi->s_mount_state & EXT2_VALID_FS))
 513                 printk ("EXT2-fs warning: mounting unchecked fs, "
 514                         "running e2fsck is recommended\n");
 515         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 516                 printk ("EXT2-fs warning: mounting fs with errors, "
 517                         "running e2fsck is recommended\n");
 518         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 519                  le16_to_cpu(es->s_mnt_count) >=
 520                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 521                 printk ("EXT2-fs warning: maximal mount count reached, "
 522                         "running e2fsck is recommended\n");
 523         else if (le32_to_cpu(es->s_checkinterval) &&
 524                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 525                 printk ("EXT2-fs warning: checktime reached, "
 526                         "running e2fsck is recommended\n");
 527         if (!le16_to_cpu(es->s_max_mnt_count))
 528                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 529         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
 530         ext2_write_super(sb);
 531         if (test_opt (sb, DEBUG))
 532                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
 533                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
 534                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 535                         sbi->s_frag_size,
 536                         sbi->s_groups_count,
 537                         EXT2_BLOCKS_PER_GROUP(sb),
 538                         EXT2_INODES_PER_GROUP(sb),
 539                         sbi->s_mount_opt);
 540         return res;
 541 }
 542
 543 static int ext2_check_descriptors (struct super_block * sb)
 544 {
 545         int i;
 546         int desc_block = 0;
 547         struct ext2_sb_info *sbi = EXT2_SB(sb);
 548         unsigned long first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 549         unsigned long last_block;
 550         struct ext2_group_desc * gdp = NULL;
 551
 552         ext2_debug ("Checking group descriptors");
 553
 554         for (i = 0; i < sbi->s_groups_count; i++)
 555         {
 556                 if (i == sbi->s_groups_count - 1)
 557                         last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
 558                 else
 559                         last_block = first_block +
 560                                 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
 561
 562                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
 563                         gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
 564                 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
 565                     le32_to_cpu(gdp->bg_block_bitmap) > last_block)
 566                 {
 567                         ext2_error (sb, "ext2_check_descriptors",
 568                                     "Block bitmap for group %d"
 569                                     " not in group (block %lu)!",
 570                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 571                         return 0;
 572                 }
 573                 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
 574                     le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
 575                 {
 576                         ext2_error (sb, "ext2_check_descriptors",
 577                                     "Inode bitmap for group %d"
 578                                     " not in group (block %lu)!",
 579                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 580                         return 0;
 581                 }
 582                 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
 583                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >
 584                     last_block)
 585                 {
 586                         ext2_error (sb, "ext2_check_descriptors",
 587                                     "Inode table for group %d"
 588                                     " not in group (block %lu)!",
 589                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 590                         return 0;
 591                 }
 592                 first_block += EXT2_BLOCKS_PER_GROUP(sb);
 593                 gdp++;
 594         }
 595         return 1;
 596 }
 597
 598 /*
 599  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 600  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 601  * We need to be 1 filesystem block less than the 2^32 sector limit.
 602  */
 603 static loff_t ext2_max_size(int bits)
 604 {
 605         loff_t res = EXT2_NDIR_BLOCKS;
 606         /* This constant is calculated to be the largest file size for a
 607          * dense, 4k-blocksize file such that the total number of
 608          * sectors in the file, including data and all indirect blocks,
 609          * does not exceed 2^32. */
 610         const loff_t upper_limit = 0x1ff7fffd000LL;
 611
 612         res += 1LL << (bits-2);
 613         res += 1LL << (2*(bits-2));
 614         res += 1LL << (3*(bits-2));
 615         res <<= bits;
 616         if (res > upper_limit)
 617                 res = upper_limit;
 618         return res;
 619 }
 620
 621 static unsigned long descriptor_loc(struct super_block *sb,
 622                                     unsigned long logic_sb_block,
 623                                     int nr)
 624 {
 625         struct ext2_sb_info *sbi = EXT2_SB(sb);
 626         unsigned long bg, first_data_block, first_meta_bg;
 627         int has_super = 0;
 628
 629         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 630         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 631
 632         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 633             nr < first_meta_bg)
 634                 return (logic_sb_block + nr + 1);
 635         bg = sbi->s_desc_per_block * nr;
 636         if (ext2_bg_has_super(sb, bg))
 637                 has_super = 1;
 638         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
 639 }
 640
 641 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 642 {
 643         struct buffer_head * bh;
 644         struct ext2_sb_info * sbi;
 645         struct ext2_super_block * es;
 646         struct inode *root;
 647         unsigned long block;
 648         unsigned long sb_block = get_sb_block(&data);
 649         unsigned long logic_sb_block;
 650         unsigned long offset = 0;
 651         unsigned long def_mount_opts;
 652         int blocksize = BLOCK_SIZE;
 653         int db_count;
 654         int i, j;
 655         __le32 features;
 656
 657         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 658         if (!sbi)
 659                 return -ENOMEM;
 660         sb->s_fs_info = sbi;
 661
 662         /*
 663          * See what the current blocksize for the device is, and
 664          * use that as the blocksize.  Otherwise (or if the blocksize
 665          * is smaller than the default) use the default.
 666          * This is important for devices that have a hardware
 667          * sectorsize that is larger than the default.
 668          */
 669         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 670         if (!blocksize) {
 671                 printk ("EXT2-fs: unable to set blocksize\n");
 672                 goto failed_sbi;
 673         }
 674
 675         /*
 676          * If the superblock doesn't start on a hardware sector boundary,
 677          * calculate the offset.
 678          */
 679         if (blocksize != BLOCK_SIZE) {
 680                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 681                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 682         } else {
 683                 logic_sb_block = sb_block;
 684         }
 685
 686         if (!(bh = sb_bread(sb, logic_sb_block))) {
 687                 printk ("EXT2-fs: unable to read superblock\n");
 688                 goto failed_sbi;
 689         }
 690         /*
 691          * Note: s_es must be initialized as soon as possible because
 692          *       some ext2 macro-instructions depend on its value
 693          */
 694         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 695         sbi->s_es = es;
 696         sb->s_magic = le16_to_cpu(es->s_magic);
 697
 698         if (sb->s_magic != EXT2_SUPER_MAGIC)
 699                 goto cantfind_ext2;
 700
 701         /* Set defaults before we parse the mount options */
 702         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 703         if (def_mount_opts & EXT2_DEFM_DEBUG)
 704                 set_opt(sbi->s_mount_opt, DEBUG);
 705         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 706                 set_opt(sbi->s_mount_opt, GRPID);
 707         if (def_mount_opts & EXT2_DEFM_UID16)
 708                 set_opt(sbi->s_mount_opt, NO_UID32);
 709 #ifdef CONFIG_EXT2_FS_XATTR
 710         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 711                 set_opt(sbi->s_mount_opt, XATTR_USER);
 712 #endif
 713 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 714         if (def_mount_opts & EXT2_DEFM_ACL)
 715                 set_opt(sbi->s_mount_opt, POSIX_ACL);
 716 #endif
 717
 718         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 719                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 720         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
 721                 set_opt(sbi->s_mount_opt, ERRORS_RO);
 722         else
 723                 set_opt(sbi->s_mount_opt, ERRORS_CONT);
 724
 725         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
 726         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
 727
 728         if (!parse_options ((char *) data, sbi))
 729                 goto failed_mount;
 730
 731         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 732                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 733                  MS_POSIXACL : 0);
 734
 735         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
 736                                     EXT2_MOUNT_XIP if not */
 737
 738         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 739             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 740              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 741              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 742                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
 743                        "running e2fsck is recommended\n");
 744         /*
 745          * Check feature flags regardless of the revision level, since we
 746          * previously didn't change the revision level when setting the flags,
 747          * so there is a chance incompat flags are set on a rev 0 filesystem.
 748          */
 749         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 750         if (features) {
 751                 printk("EXT2-fs: %s: couldn't mount because of "
 752                        "unsupported optional features (%x).\n",
 753                        sb->s_id, le32_to_cpu(features));
 754                 goto failed_mount;
 755         }
 756         if (!(sb->s_flags & MS_RDONLY) &&
 757             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 758                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
 759                        "unsupported optional features (%x).\n",
 760                        sb->s_id, le32_to_cpu(features));
 761                 goto failed_mount;
 762         }
 763
 764         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 765
 766         if ((ext2_use_xip(sb)) && ((blocksize != PAGE_SIZE) ||
 767                                   (sb->s_blocksize != blocksize))) {
 768                 if (!silent)
 769                         printk("XIP: Unsupported blocksize\n");
 770                 goto failed_mount;
 771         }
 772
 773         /* If the blocksize doesn't match, re-read the thing.. */
 774         if (sb->s_blocksize != blocksize) {
 775                 brelse(bh);
 776
 777                 if (!sb_set_blocksize(sb, blocksize)) {
 778                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
 779                         goto failed_sbi;
 780                 }
 781
 782                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 783                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 784                 bh = sb_bread(sb, logic_sb_block);
 785                 if(!bh) {
 786                         printk("EXT2-fs: Couldn't read superblock on "
 787                                "2nd try.\n");
 788                         goto failed_sbi;
 789                 }
 790                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 791                 sbi->s_es = es;
 792                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 793                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
 794                         goto failed_mount;
 795                 }
 796         }
 797
 798         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 799
 800         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 801                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 802                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 803         } else {
 804                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 805                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 806                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 807                     (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
 808                     (sbi->s_inode_size > blocksize)) {
 809                         printk ("EXT2-fs: unsupported inode size: %d\n",
 810                                 sbi->s_inode_size);
 811                         goto failed_mount;
 812                 }
 813         }
 814
 815         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 816                                    le32_to_cpu(es->s_log_frag_size);
 817         if (sbi->s_frag_size == 0)
 818                 goto cantfind_ext2;
 819         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
 820
 821         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 822         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 823         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 824
 825         if (EXT2_INODE_SIZE(sb) == 0)
 826                 goto cantfind_ext2;
 827         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
 828         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
 829                 goto cantfind_ext2;
 830         sbi->s_itb_per_group = sbi->s_inodes_per_group /
 831                                         sbi->s_inodes_per_block;
 832         sbi->s_desc_per_block = sb->s_blocksize /
 833                                         sizeof (struct ext2_group_desc);
 834         sbi->s_sbh = bh;
 835         sbi->s_mount_state = le16_to_cpu(es->s_state);
 836         sbi->s_addr_per_block_bits =
 837                 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
 838         sbi->s_desc_per_block_bits =
 839                 ilog2 (EXT2_DESC_PER_BLOCK(sb));
 840
 841         if (sb->s_magic != EXT2_SUPER_MAGIC)
 842                 goto cantfind_ext2;
 843
 844         if (sb->s_blocksize != bh->b_size) {
 845                 if (!silent)
 846                         printk ("VFS: Unsupported blocksize on dev "
 847                                 "%s.\n", sb->s_id);
 848                 goto failed_mount;
 849         }
 850
 851         if (sb->s_blocksize != sbi->s_frag_size) {
 852                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
 853                         sbi->s_frag_size, sb->s_blocksize);
 854                 goto failed_mount;
 855         }
 856
 857         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
 858                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
 859                         sbi->s_blocks_per_group);
 860                 goto failed_mount;
 861         }
 862         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 863                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
 864                         sbi->s_frags_per_group);
 865                 goto failed_mount;
 866         }
 867         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
 868                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
 869                         sbi->s_inodes_per_group);
 870                 goto failed_mount;
 871         }
 872
 873         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
 874                 goto cantfind_ext2;
 875         sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
 876                                 le32_to_cpu(es->s_first_data_block) - 1)
 877                                         / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
 878         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
 879                    EXT2_DESC_PER_BLOCK(sb);
 880         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
 881         if (sbi->s_group_desc == NULL) {
 882                 printk ("EXT2-fs: not enough memory\n");
 883                 goto failed_mount;
 884         }
 885         bgl_lock_init(&sbi->s_blockgroup_lock);
 886         sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
 887         if (!sbi->s_debts) {
 888                 printk ("EXT2-fs: not enough memory\n");
 889                 goto failed_mount_group_desc;
 890         }
 891         for (i = 0; i < db_count; i++) {
 892                 block = descriptor_loc(sb, logic_sb_block, i);
 893                 sbi->s_group_desc[i] = sb_bread(sb, block);
 894                 if (!sbi->s_group_desc[i]) {
 895                         for (j = 0; j < i; j++)
 896                                 brelse (sbi->s_group_desc[j]);
 897                         printk ("EXT2-fs: unable to read group descriptors\n");
 898                         goto failed_mount_group_desc;
 899                 }
 900         }
 901         if (!ext2_check_descriptors (sb)) {
 902                 printk ("EXT2-fs: group descriptors corrupted!\n");
 903                 goto failed_mount2;
 904         }
 905         sbi->s_gdb_count = db_count;
 906         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
 907         spin_lock_init(&sbi->s_next_gen_lock);
 908
 909         percpu_counter_init(&sbi->s_freeblocks_counter,
 910                                 ext2_count_free_blocks(sb));
 911         percpu_counter_init(&sbi->s_freeinodes_counter,
 912                                 ext2_count_free_inodes(sb));
 913         percpu_counter_init(&sbi->s_dirs_counter,
 914                                 ext2_count_dirs(sb));
 915         /*
 916          * set up enough so that it can read an inode
 917          */
 918         sb->s_op = &ext2_sops;
 919         sb->s_export_op = &ext2_export_ops;
 920         sb->s_xattr = ext2_xattr_handlers;
 921         root = iget(sb, EXT2_ROOT_INO);
 922         sb->s_root = d_alloc_root(root);
 923         if (!sb->s_root) {
 924                 iput(root);
 925                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
 926                 goto failed_mount3;
 927         }
 928         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
 929                 dput(sb->s_root);
 930                 sb->s_root = NULL;
 931                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
 932                 goto failed_mount3;
 933         }
 934         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 935                 ext2_warning(sb, __FUNCTION__,
 936                         "mounting ext3 filesystem as ext2");
 937         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
 938         return 0;
 939
 940 cantfind_ext2:
 941         if (!silent)
 942                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
 943                        sb->s_id);
 944         goto failed_mount;
 945 failed_mount3:
 946         percpu_counter_destroy(&sbi->s_freeblocks_counter);
 947         percpu_counter_destroy(&sbi->s_freeinodes_counter);
 948         percpu_counter_destroy(&sbi->s_dirs_counter);
 949 failed_mount2:
 950         for (i = 0; i < db_count; i++)
 951                 brelse(sbi->s_group_desc[i]);
 952 failed_mount_group_desc:
 953         kfree(sbi->s_group_desc);
 954         kfree(sbi->s_debts);
 955 failed_mount:
 956         brelse(bh);
 957 failed_sbi:
 958         sb->s_fs_info = NULL;
 959         kfree(sbi);
 960         return -EINVAL;
 961 }
 962
 963 static void ext2_commit_super (struct super_block * sb,
 964                                struct ext2_super_block * es)
 965 {
 966         es->s_wtime = cpu_to_le32(get_seconds());
 967         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 968         sb->s_dirt = 0;
 969 }
 970
 971 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
 972 {
 973         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 974         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 975         es->s_wtime = cpu_to_le32(get_seconds());
 976         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 977         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
 978         sb->s_dirt = 0;
 979 }
 980
 981 /*
 982  * In the second extended file system, it is not necessary to
 983  * write the super block since we use a mapping of the
 984  * disk super block in a buffer.
 985  *
 986  * However, this function is still used to set the fs valid
 987  * flags to 0.  We need to set this flag to 0 since the fs
 988  * may have been checked while mounted and e2fsck may have
 989  * set s_state to EXT2_VALID_FS after some corrections.
 990  */
 991
 992 void ext2_write_super (struct super_block * sb)
 993 {
 994         struct ext2_super_block * es;
 995         lock_kernel();
 996         if (!(sb->s_flags & MS_RDONLY)) {
 997                 es = EXT2_SB(sb)->s_es;
 998
 999                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
1000                         ext2_debug ("setting valid to 0\n");
1001                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
1002                                                   ~EXT2_VALID_FS);
1003                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1004                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1005                         es->s_mtime = cpu_to_le32(get_seconds());
1006                         ext2_sync_super(sb, es);
1007                 } else
1008                         ext2_commit_super (sb, es);
1009         }
1010         sb->s_dirt = 0;
1011         unlock_kernel();
1012 }
1013
1014 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1015 {
1016         struct ext2_sb_info * sbi = EXT2_SB(sb);
1017         struct ext2_super_block * es;
1018         unsigned long old_mount_opt = sbi->s_mount_opt;
1019         struct ext2_mount_options old_opts;
1020         unsigned long old_sb_flags;
1021         int err;
1022
1023         /* Store the old options */
1024         old_sb_flags = sb->s_flags;
1025         old_opts.s_mount_opt = sbi->s_mount_opt;
1026         old_opts.s_resuid = sbi->s_resuid;
1027         old_opts.s_resgid = sbi->s_resgid;
1028
1029         /*
1030          * Allow the "check" option to be passed as a remount option.
1031          */
1032         if (!parse_options (data, sbi)) {
1033                 err = -EINVAL;
1034                 goto restore_opts;
1035         }
1036
1037         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1038                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1039
1040         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
1041                                     EXT2_MOUNT_XIP if not */
1042
1043         if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
1044                 printk("XIP: Unsupported blocksize\n");
1045                 err = -EINVAL;
1046                 goto restore_opts;
1047         }
1048
1049         es = sbi->s_es;
1050         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
1051             (old_mount_opt & EXT2_MOUNT_XIP)) &&
1052             invalidate_inodes(sb))
1053                 ext2_warning(sb, __FUNCTION__, "busy inodes while remounting "\
1054                              "xip remain in cache (no functional problem)");
1055         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1056                 return 0;
1057         if (*flags & MS_RDONLY) {
1058                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1059                     !(sbi->s_mount_state & EXT2_VALID_FS))
1060                         return 0;
1061                 /*
1062                  * OK, we are remounting a valid rw partition rdonly, so set
1063                  * the rdonly flag and then mark the partition as valid again.
1064                  */
1065                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1066                 es->s_mtime = cpu_to_le32(get_seconds());
1067         } else {
1068                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1069                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1070                 if (ret) {
1071                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
1072                                "unsupported optional features (%x).\n",
1073                                sb->s_id, le32_to_cpu(ret));
1074                         err = -EROFS;
1075                         goto restore_opts;
1076                 }
1077                 /*
1078                  * Mounting a RDONLY partition read-write, so reread and
1079                  * store the current valid flag.  (It may have been changed
1080                  * by e2fsck since we originally mounted the partition.)
1081                  */
1082                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1083                 if (!ext2_setup_super (sb, es, 0))
1084                         sb->s_flags &= ~MS_RDONLY;
1085         }
1086         ext2_sync_super(sb, es);
1087         return 0;
1088 restore_opts:
1089         sbi->s_mount_opt = old_opts.s_mount_opt;
1090         sbi->s_resuid = old_opts.s_resuid;
1091         sbi->s_resgid = old_opts.s_resgid;
1092         sb->s_flags = old_sb_flags;
1093         return err;
1094 }
1095
1096 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1097 {
1098         struct super_block *sb = dentry->d_sb;
1099         struct ext2_sb_info *sbi = EXT2_SB(sb);
1100         struct ext2_super_block *es = sbi->s_es;
1101         u64 fsid;
1102
1103         if (test_opt (sb, MINIX_DF))
1104                 sbi->s_overhead_last = 0;
1105         else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1106                 unsigned long i, overhead = 0;
1107                 smp_rmb();
1108
1109                 /*
1110                  * Compute the overhead (FS structures). This is constant
1111                  * for a given filesystem unless the number of block groups
1112                  * changes so we cache the previous value until it does.
1113                  */
1114
1115                 /*
1116                  * All of the blocks before first_data_block are
1117                  * overhead
1118                  */
1119                 overhead = le32_to_cpu(es->s_first_data_block);
1120
1121                 /*
1122                  * Add the overhead attributed to the superblock and
1123                  * block group descriptors.  If the sparse superblocks
1124                  * feature is turned on, then not all groups have this.
1125                  */
1126                 for (i = 0; i < sbi->s_groups_count; i++)
1127                         overhead += ext2_bg_has_super(sb, i) +
1128                                 ext2_bg_num_gdb(sb, i);
1129
1130                 /*
1131                  * Every block group has an inode bitmap, a block
1132                  * bitmap, and an inode table.
1133                  */
1134                 overhead += (sbi->s_groups_count *
1135                              (2 + sbi->s_itb_per_group));
1136                 sbi->s_overhead_last = overhead;
1137                 smp_wmb();
1138                 sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1139         }
1140
1141         buf->f_type = EXT2_SUPER_MAGIC;
1142         buf->f_bsize = sb->s_blocksize;
1143         buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1144         buf->f_bfree = ext2_count_free_blocks(sb);
1145         es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1146         buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1147         if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1148                 buf->f_bavail = 0;
1149         buf->f_files = le32_to_cpu(es->s_inodes_count);
1150         buf->f_ffree = ext2_count_free_inodes(sb);
1151         es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1152         buf->f_namelen = EXT2_NAME_LEN;
1153         fsid = le64_to_cpup((void *)es->s_uuid) ^
1154                le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1155         buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1156         buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1157         return 0;
1158 }
1159
1160 static int ext2_get_sb(struct file_system_type *fs_type,
1161         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1162 {
1163         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super, mnt);
1164 }
1165
1166 #ifdef CONFIG_QUOTA
1167
1168 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1169  * acquiring the locks... As quota files are never truncated and quota code
1170  * itself serializes the operations (and noone else should touch the files)
1171  * we don't have to be afraid of races */
1172 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1173                                size_t len, loff_t off)
1174 {
1175         struct inode *inode = sb_dqopt(sb)->files[type];
1176         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1177         int err = 0;
1178         int offset = off & (sb->s_blocksize - 1);
1179         int tocopy;
1180         size_t toread;
1181         struct buffer_head tmp_bh;
1182         struct buffer_head *bh;
1183         loff_t i_size = i_size_read(inode);
1184
1185         if (off > i_size)
1186                 return 0;
1187         if (off+len > i_size)
1188                 len = i_size-off;
1189         toread = len;
1190         while (toread > 0) {
1191                 tocopy = sb->s_blocksize - offset < toread ?
1192                                 sb->s_blocksize - offset : toread;
1193
1194                 tmp_bh.b_state = 0;
1195                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1196                 if (err)
1197                         return err;
1198                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1199                         memset(data, 0, tocopy);
1200                 else {
1201                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1202                         if (!bh)
1203                                 return -EIO;
1204                         memcpy(data, bh->b_data+offset, tocopy);
1205                         brelse(bh);
1206                 }
1207                 offset = 0;
1208                 toread -= tocopy;
1209                 data += tocopy;
1210                 blk++;
1211         }
1212         return len;
1213 }
1214
1215 /* Write to quotafile */
1216 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1217                                 const char *data, size_t len, loff_t off)
1218 {
1219         struct inode *inode = sb_dqopt(sb)->files[type];
1220         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1221         int err = 0;
1222         int offset = off & (sb->s_blocksize - 1);
1223         int tocopy;
1224         size_t towrite = len;
1225         struct buffer_head tmp_bh;
1226         struct buffer_head *bh;
1227
1228         mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1229         while (towrite > 0) {
1230                 tocopy = sb->s_blocksize - offset < towrite ?
1231                                 sb->s_blocksize - offset : towrite;
1232
1233                 tmp_bh.b_state = 0;
1234                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1235                 if (err)
1236                         goto out;
1237                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1238                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1239                 else
1240                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1241                 if (!bh) {
1242                         err = -EIO;
1243                         goto out;
1244                 }
1245                 lock_buffer(bh);
1246                 memcpy(bh->b_data+offset, data, tocopy);
1247                 flush_dcache_page(bh->b_page);
1248                 set_buffer_uptodate(bh);
1249                 mark_buffer_dirty(bh);
1250                 unlock_buffer(bh);
1251                 brelse(bh);
1252                 offset = 0;
1253                 towrite -= tocopy;
1254                 data += tocopy;
1255                 blk++;
1256         }
1257 out:
1258         if (len == towrite)
1259                 return err;
1260         if (inode->i_size < off+len-towrite)
1261                 i_size_write(inode, off+len-towrite);
1262         inode->i_version++;
1263         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1264         mark_inode_dirty(inode);
1265         mutex_unlock(&inode->i_mutex);
1266         return len - towrite;
1267 }
1268
1269 #endif
1270
1271 static struct file_system_type ext2_fs_type = {
1272         .owner          = THIS_MODULE,
1273         .name           = "ext2",
1274         .get_sb         = ext2_get_sb,
1275         .kill_sb        = kill_block_super,
1276         .fs_flags       = FS_REQUIRES_DEV,
1277 };
1278
1279 static int __init init_ext2_fs(void)
1280 {
1281         int err = init_ext2_xattr();
1282         if (err)
1283                 return err;
1284         err = init_inodecache();
1285         if (err)
1286                 goto out1;
1287         err = register_filesystem(&ext2_fs_type);
1288         if (err)
1289                 goto out;
1290         return 0;
1291 out:
1292         destroy_inodecache();
1293 out1:
1294         exit_ext2_xattr();
1295         return err;
1296 }
1297
1298 static void __exit exit_ext2_fs(void)
1299 {
1300         unregister_filesystem(&ext2_fs_type);
1301         destroy_inodecache();
1302         exit_ext2_xattr();
1303 }
1304
1305 module_init(init_ext2_fs)
1306 module_exit(exit_ext2_fs)