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/fs.h>
  23 #include <linux/slab.h>
  24 #include <linux/init.h>
  25 #include <linux/blkdev.h>
  26 #include <linux/parser.h>
  27 #include <linux/random.h>
  28 #include <linux/buffer_head.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 super_block * sb, 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 kmem_cache_t * 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, SLAB_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, kmem_cache_t * cachep, unsigned long flags)
 161 {
 162         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
 163
 164         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 165             SLAB_CTOR_CONSTRUCTOR) {
 166                 rwlock_init(&ei->i_meta_lock);
 167 #ifdef CONFIG_EXT2_FS_XATTR
 168                 init_rwsem(&ei->xattr_sem);
 169 #endif
 170                 inode_init_once(&ei->vfs_inode);
 171         }
 172 }
 173
 174 static int init_inodecache(void)
 175 {
 176         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
 177                                              sizeof(struct ext2_inode_info),
 178                                              0, (SLAB_RECLAIM_ACCOUNT|
 179                                                 SLAB_MEM_SPREAD),
 180                                              init_once, NULL);
 181         if (ext2_inode_cachep == NULL)
 182                 return -ENOMEM;
 183         return 0;
 184 }
 185
 186 static void destroy_inodecache(void)
 187 {
 188         if (kmem_cache_destroy(ext2_inode_cachep))
 189                 printk(KERN_INFO "ext2_inode_cache: not all structures were freed\n");
 190 }
 191
 192 static void ext2_clear_inode(struct inode *inode)
 193 {
 194 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 195         struct ext2_inode_info *ei = EXT2_I(inode);
 196
 197         if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
 198                 posix_acl_release(ei->i_acl);
 199                 ei->i_acl = EXT2_ACL_NOT_CACHED;
 200         }
 201         if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
 202                 posix_acl_release(ei->i_default_acl);
 203                 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 204         }
 205 #endif
 206 }
 207
 208 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
 209 {
 210         struct ext2_sb_info *sbi = EXT2_SB(vfs->mnt_sb);
 211
 212         if (sbi->s_mount_opt & EXT2_MOUNT_GRPID)
 213                 seq_puts(seq, ",grpid");
 214
 215 #if defined(CONFIG_QUOTA)
 216         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
 217                 seq_puts(seq, ",usrquota");
 218
 219         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
 220                 seq_puts(seq, ",grpquota");
 221 #endif
 222
 223 #if defined(CONFIG_EXT2_FS_XIP)
 224         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
 225                 seq_puts(seq, ",xip");
 226 #endif
 227
 228         return 0;
 229 }
 230
 231 #ifdef CONFIG_QUOTA
 232 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
 233 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
 234 #endif
 235
 236 static struct super_operations ext2_sops = {
 237         .alloc_inode    = ext2_alloc_inode,
 238         .destroy_inode  = ext2_destroy_inode,
 239         .read_inode     = ext2_read_inode,
 240         .write_inode    = ext2_write_inode,
 241         .put_inode      = ext2_put_inode,
 242         .delete_inode   = ext2_delete_inode,
 243         .put_super      = ext2_put_super,
 244         .write_super    = ext2_write_super,
 245         .statfs         = ext2_statfs,
 246         .remount_fs     = ext2_remount,
 247         .clear_inode    = ext2_clear_inode,
 248         .show_options   = ext2_show_options,
 249 #ifdef CONFIG_QUOTA
 250         .quota_read     = ext2_quota_read,
 251         .quota_write    = ext2_quota_write,
 252 #endif
 253 };
 254
 255 /* Yes, most of these are left as NULL!!
 256  * A NULL value implies the default, which works with ext2-like file
 257  * systems, but can be improved upon.
 258  * Currently only get_parent is required.
 259  */
 260 static struct export_operations ext2_export_ops = {
 261         .get_parent = ext2_get_parent,
 262 };
 263
 264 static unsigned long get_sb_block(void **data)
 265 {
 266         unsigned long   sb_block;
 267         char            *options = (char *) *data;
 268
 269         if (!options || strncmp(options, "sb=", 3) != 0)
 270                 return 1;       /* Default location */
 271         options += 3;
 272         sb_block = simple_strtoul(options, &options, 0);
 273         if (*options && *options != ',') {
 274                 printk("EXT2-fs: Invalid sb specification: %s\n",
 275                        (char *) *data);
 276                 return 1;
 277         }
 278         if (*options == ',')
 279                 options++;
 280         *data = (void *) options;
 281         return sb_block;
 282 }
 283
 284 enum {
 285         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
 286         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
 287         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
 288         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
 289         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
 290         Opt_usrquota, Opt_grpquota, Opt_tagxid
 291 };
 292
 293 static match_table_t tokens = {
 294         {Opt_bsd_df, "bsddf"},
 295         {Opt_minix_df, "minixdf"},
 296         {Opt_grpid, "grpid"},
 297         {Opt_grpid, "bsdgroups"},
 298         {Opt_nogrpid, "nogrpid"},
 299         {Opt_nogrpid, "sysvgroups"},
 300         {Opt_resgid, "resgid=%u"},
 301         {Opt_resuid, "resuid=%u"},
 302         {Opt_sb, "sb=%u"},
 303         {Opt_err_cont, "errors=continue"},
 304         {Opt_err_panic, "errors=panic"},
 305         {Opt_err_ro, "errors=remount-ro"},
 306         {Opt_nouid32, "nouid32"},
 307         {Opt_nocheck, "check=none"},
 308         {Opt_nocheck, "nocheck"},
 309         {Opt_debug, "debug"},
 310         {Opt_oldalloc, "oldalloc"},
 311         {Opt_orlov, "orlov"},
 312         {Opt_nobh, "nobh"},
 313         {Opt_user_xattr, "user_xattr"},
 314         {Opt_nouser_xattr, "nouser_xattr"},
 315         {Opt_acl, "acl"},
 316         {Opt_noacl, "noacl"},
 317         {Opt_xip, "xip"},
 318         {Opt_tagxid, "tagxid"},
 319         {Opt_grpquota, "grpquota"},
 320         {Opt_ignore, "noquota"},
 321         {Opt_quota, "quota"},
 322         {Opt_usrquota, "usrquota"},
 323         {Opt_err, NULL}
 324 };
 325
 326 static int parse_options (char * options,
 327                           struct ext2_sb_info *sbi)
 328 {
 329         char * p;
 330         substring_t args[MAX_OPT_ARGS];
 331         unsigned long kind = EXT2_MOUNT_ERRORS_CONT;
 332         int option;
 333
 334         if (!options)
 335                 return 1;
 336
 337         while ((p = strsep (&options, ",")) != NULL) {
 338                 int token;
 339                 if (!*p)
 340                         continue;
 341
 342                 token = match_token(p, tokens, args);
 343                 switch (token) {
 344                 case Opt_bsd_df:
 345                         clear_opt (sbi->s_mount_opt, MINIX_DF);
 346                         break;
 347                 case Opt_minix_df:
 348                         set_opt (sbi->s_mount_opt, MINIX_DF);
 349                         break;
 350                 case Opt_grpid:
 351                         set_opt (sbi->s_mount_opt, GRPID);
 352                         break;
 353                 case Opt_nogrpid:
 354                         clear_opt (sbi->s_mount_opt, GRPID);
 355                         break;
 356                 case Opt_resuid:
 357                         if (match_int(&args[0], &option))
 358                                 return 0;
 359                         sbi->s_resuid = option;
 360                         break;
 361                 case Opt_resgid:
 362                         if (match_int(&args[0], &option))
 363                                 return 0;
 364                         sbi->s_resgid = option;
 365                         break;
 366                 case Opt_sb:
 367                         /* handled by get_sb_block() instead of here */
 368                         /* *sb_block = match_int(&args[0]); */
 369                         break;
 370                 case Opt_err_panic:
 371                         kind = EXT2_MOUNT_ERRORS_PANIC;
 372                         break;
 373                 case Opt_err_ro:
 374                         kind = EXT2_MOUNT_ERRORS_RO;
 375                         break;
 376                 case Opt_err_cont:
 377                         kind = EXT2_MOUNT_ERRORS_CONT;
 378                         break;
 379                 case Opt_nouid32:
 380                         set_opt (sbi->s_mount_opt, NO_UID32);
 381                         break;
 382 #ifndef CONFIG_INOXID_NONE
 383                 case Opt_tagxid:
 384                         set_opt (sbi->s_mount_opt, TAGXID);
 385                         break;
 386 #endif
 387                 case Opt_nocheck:
 388                         clear_opt (sbi->s_mount_opt, CHECK);
 389                         break;
 390                 case Opt_debug:
 391                         set_opt (sbi->s_mount_opt, DEBUG);
 392                         break;
 393                 case Opt_oldalloc:
 394                         set_opt (sbi->s_mount_opt, OLDALLOC);
 395                         break;
 396                 case Opt_orlov:
 397                         clear_opt (sbi->s_mount_opt, OLDALLOC);
 398                         break;
 399                 case Opt_nobh:
 400                         set_opt (sbi->s_mount_opt, NOBH);
 401                         break;
 402 #ifdef CONFIG_EXT2_FS_XATTR
 403                 case Opt_user_xattr:
 404                         set_opt (sbi->s_mount_opt, XATTR_USER);
 405                         break;
 406                 case Opt_nouser_xattr:
 407                         clear_opt (sbi->s_mount_opt, XATTR_USER);
 408                         break;
 409 #else
 410                 case Opt_user_xattr:
 411                 case Opt_nouser_xattr:
 412                         printk("EXT2 (no)user_xattr options not supported\n");
 413                         break;
 414 #endif
 415 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 416                 case Opt_acl:
 417                         set_opt(sbi->s_mount_opt, POSIX_ACL);
 418                         break;
 419                 case Opt_noacl:
 420                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
 421                         break;
 422 #else
 423                 case Opt_acl:
 424                 case Opt_noacl:
 425                         printk("EXT2 (no)acl options not supported\n");
 426                         break;
 427 #endif
 428                 case Opt_xip:
 429 #ifdef CONFIG_EXT2_FS_XIP
 430                         set_opt (sbi->s_mount_opt, XIP);
 431 #else
 432                         printk("EXT2 xip option not supported\n");
 433 #endif
 434                         break;
 435
 436 #if defined(CONFIG_QUOTA)
 437                 case Opt_quota:
 438                 case Opt_usrquota:
 439                         set_opt(sbi->s_mount_opt, USRQUOTA);
 440                         break;
 441
 442                 case Opt_grpquota:
 443                         set_opt(sbi->s_mount_opt, GRPQUOTA);
 444                         break;
 445 #else
 446                 case Opt_quota:
 447                 case Opt_usrquota:
 448                 case Opt_grpquota:
 449                         printk(KERN_ERR
 450                                 "EXT2-fs: quota operations not supported.\n");
 451
 452                         break;
 453 #endif
 454
 455                 case Opt_ignore:
 456                         break;
 457                 default:
 458                         return 0;
 459                 }
 460         }
 461         sbi->s_mount_opt |= kind;
 462         return 1;
 463 }
 464
 465 static int ext2_setup_super (struct super_block * sb,
 466                               struct ext2_super_block * es,
 467                               int read_only)
 468 {
 469         int res = 0;
 470         struct ext2_sb_info *sbi = EXT2_SB(sb);
 471
 472         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 473                 printk ("EXT2-fs warning: revision level too high, "
 474                         "forcing read-only mode\n");
 475                 res = MS_RDONLY;
 476         }
 477         if (read_only)
 478                 return res;
 479         if (!(sbi->s_mount_state & EXT2_VALID_FS))
 480                 printk ("EXT2-fs warning: mounting unchecked fs, "
 481                         "running e2fsck is recommended\n");
 482         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 483                 printk ("EXT2-fs warning: mounting fs with errors, "
 484                         "running e2fsck is recommended\n");
 485         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 486                  le16_to_cpu(es->s_mnt_count) >=
 487                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 488                 printk ("EXT2-fs warning: maximal mount count reached, "
 489                         "running e2fsck is recommended\n");
 490         else if (le32_to_cpu(es->s_checkinterval) &&
 491                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 492                 printk ("EXT2-fs warning: checktime reached, "
 493                         "running e2fsck is recommended\n");
 494         if (!le16_to_cpu(es->s_max_mnt_count))
 495                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 496         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
 497         ext2_write_super(sb);
 498         if (test_opt (sb, DEBUG))
 499                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
 500                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
 501                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 502                         sbi->s_frag_size,
 503                         sbi->s_groups_count,
 504                         EXT2_BLOCKS_PER_GROUP(sb),
 505                         EXT2_INODES_PER_GROUP(sb),
 506                         sbi->s_mount_opt);
 507         return res;
 508 }
 509
 510 static int ext2_check_descriptors (struct super_block * sb)
 511 {
 512         int i;
 513         int desc_block = 0;
 514         struct ext2_sb_info *sbi = EXT2_SB(sb);
 515         unsigned long block = le32_to_cpu(sbi->s_es->s_first_data_block);
 516         struct ext2_group_desc * gdp = NULL;
 517
 518         ext2_debug ("Checking group descriptors");
 519
 520         for (i = 0; i < sbi->s_groups_count; i++)
 521         {
 522                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
 523                         gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
 524                 if (le32_to_cpu(gdp->bg_block_bitmap) < block ||
 525                     le32_to_cpu(gdp->bg_block_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 526                 {
 527                         ext2_error (sb, "ext2_check_descriptors",
 528                                     "Block bitmap for group %d"
 529                                     " not in group (block %lu)!",
 530                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 531                         return 0;
 532                 }
 533                 if (le32_to_cpu(gdp->bg_inode_bitmap) < block ||
 534                     le32_to_cpu(gdp->bg_inode_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 535                 {
 536                         ext2_error (sb, "ext2_check_descriptors",
 537                                     "Inode bitmap for group %d"
 538                                     " not in group (block %lu)!",
 539                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 540                         return 0;
 541                 }
 542                 if (le32_to_cpu(gdp->bg_inode_table) < block ||
 543                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >=
 544                     block + EXT2_BLOCKS_PER_GROUP(sb))
 545                 {
 546                         ext2_error (sb, "ext2_check_descriptors",
 547                                     "Inode table for group %d"
 548                                     " not in group (block %lu)!",
 549                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 550                         return 0;
 551                 }
 552                 block += EXT2_BLOCKS_PER_GROUP(sb);
 553                 gdp++;
 554         }
 555         return 1;
 556 }
 557
 558 #define log2(n) ffz(~(n))
 559
 560 /*
 561  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 562  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 563  * We need to be 1 filesystem block less than the 2^32 sector limit.
 564  */
 565 static loff_t ext2_max_size(int bits)
 566 {
 567         loff_t res = EXT2_NDIR_BLOCKS;
 568         /* This constant is calculated to be the largest file size for a
 569          * dense, 4k-blocksize file such that the total number of
 570          * sectors in the file, including data and all indirect blocks,
 571          * does not exceed 2^32. */
 572         const loff_t upper_limit = 0x1ff7fffd000LL;
 573
 574         res += 1LL << (bits-2);
 575         res += 1LL << (2*(bits-2));
 576         res += 1LL << (3*(bits-2));
 577         res <<= bits;
 578         if (res > upper_limit)
 579                 res = upper_limit;
 580         return res;
 581 }
 582
 583 static unsigned long descriptor_loc(struct super_block *sb,
 584                                     unsigned long logic_sb_block,
 585                                     int nr)
 586 {
 587         struct ext2_sb_info *sbi = EXT2_SB(sb);
 588         unsigned long bg, first_data_block, first_meta_bg;
 589         int has_super = 0;
 590
 591         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 592         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 593
 594         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 595             nr < first_meta_bg)
 596                 return (logic_sb_block + nr + 1);
 597         bg = sbi->s_desc_per_block * nr;
 598         if (ext2_bg_has_super(sb, bg))
 599                 has_super = 1;
 600         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
 601 }
 602
 603 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 604 {
 605         struct buffer_head * bh;
 606         struct ext2_sb_info * sbi;
 607         struct ext2_super_block * es;
 608         struct inode *root;
 609         unsigned long block;
 610         unsigned long sb_block = get_sb_block(&data);
 611         unsigned long logic_sb_block;
 612         unsigned long offset = 0;
 613         unsigned long def_mount_opts;
 614         int blocksize = BLOCK_SIZE;
 615         int db_count;
 616         int i, j;
 617         __le32 features;
 618
 619         sbi = kmalloc(sizeof(*sbi), GFP_KERNEL);
 620         if (!sbi)
 621                 return -ENOMEM;
 622         sb->s_fs_info = sbi;
 623         memset(sbi, 0, sizeof(*sbi));
 624
 625         /*
 626          * See what the current blocksize for the device is, and
 627          * use that as the blocksize.  Otherwise (or if the blocksize
 628          * is smaller than the default) use the default.
 629          * This is important for devices that have a hardware
 630          * sectorsize that is larger than the default.
 631          */
 632         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 633         if (!blocksize) {
 634                 printk ("EXT2-fs: unable to set blocksize\n");
 635                 goto failed_sbi;
 636         }
 637
 638         /*
 639          * If the superblock doesn't start on a hardware sector boundary,
 640          * calculate the offset.
 641          */
 642         if (blocksize != BLOCK_SIZE) {
 643                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 644                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 645         } else {
 646                 logic_sb_block = sb_block;
 647         }
 648
 649         if (!(bh = sb_bread(sb, logic_sb_block))) {
 650                 printk ("EXT2-fs: unable to read superblock\n");
 651                 goto failed_sbi;
 652         }
 653         /*
 654          * Note: s_es must be initialized as soon as possible because
 655          *       some ext2 macro-instructions depend on its value
 656          */
 657         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 658         sbi->s_es = es;
 659         sb->s_magic = le16_to_cpu(es->s_magic);
 660
 661         if (sb->s_magic != EXT2_SUPER_MAGIC)
 662                 goto cantfind_ext2;
 663
 664         /* Set defaults before we parse the mount options */
 665         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 666         if (def_mount_opts & EXT2_DEFM_DEBUG)
 667                 set_opt(sbi->s_mount_opt, DEBUG);
 668         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 669                 set_opt(sbi->s_mount_opt, GRPID);
 670         if (def_mount_opts & EXT2_DEFM_UID16)
 671                 set_opt(sbi->s_mount_opt, NO_UID32);
 672         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 673                 set_opt(sbi->s_mount_opt, XATTR_USER);
 674         if (def_mount_opts & EXT2_DEFM_ACL)
 675                 set_opt(sbi->s_mount_opt, POSIX_ACL);
 676
 677         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 678                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 679         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
 680                 set_opt(sbi->s_mount_opt, ERRORS_RO);
 681
 682         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
 683         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
 684
 685         if (!parse_options ((char *) data, sbi))
 686                 goto failed_mount;
 687
 688         if (EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_TAGXID)
 689                 sb->s_flags |= MS_TAGXID;
 690         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 691                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 692                  MS_POSIXACL : 0);
 693
 694         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
 695                                     EXT2_MOUNT_XIP if not */
 696
 697         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 698             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 699              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 700              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 701                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
 702                        "running e2fsck is recommended\n");
 703         /*
 704          * Check feature flags regardless of the revision level, since we
 705          * previously didn't change the revision level when setting the flags,
 706          * so there is a chance incompat flags are set on a rev 0 filesystem.
 707          */
 708         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 709         if (features) {
 710                 printk("EXT2-fs: %s: couldn't mount because of "
 711                        "unsupported optional features (%x).\n",
 712                        sb->s_id, le32_to_cpu(features));
 713                 goto failed_mount;
 714         }
 715         if (!(sb->s_flags & MS_RDONLY) &&
 716             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 717                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
 718                        "unsupported optional features (%x).\n",
 719                        sb->s_id, le32_to_cpu(features));
 720                 goto failed_mount;
 721         }
 722
 723         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 724
 725         if ((ext2_use_xip(sb)) && ((blocksize != PAGE_SIZE) ||
 726                                   (sb->s_blocksize != blocksize))) {
 727                 if (!silent)
 728                         printk("XIP: Unsupported blocksize\n");
 729                 goto failed_mount;
 730         }
 731
 732         /* If the blocksize doesn't match, re-read the thing.. */
 733         if (sb->s_blocksize != blocksize) {
 734                 brelse(bh);
 735
 736                 if (!sb_set_blocksize(sb, blocksize)) {
 737                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
 738                         goto failed_sbi;
 739                 }
 740
 741                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 742                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 743                 bh = sb_bread(sb, logic_sb_block);
 744                 if(!bh) {
 745                         printk("EXT2-fs: Couldn't read superblock on "
 746                                "2nd try.\n");
 747                         goto failed_sbi;
 748                 }
 749                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 750                 sbi->s_es = es;
 751                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 752                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
 753                         goto failed_mount;
 754                 }
 755         }
 756
 757         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 758
 759         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 760                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 761                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 762         } else {
 763                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 764                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 765                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 766                     (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
 767                     (sbi->s_inode_size > blocksize)) {
 768                         printk ("EXT2-fs: unsupported inode size: %d\n",
 769                                 sbi->s_inode_size);
 770                         goto failed_mount;
 771                 }
 772         }
 773
 774         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 775                                    le32_to_cpu(es->s_log_frag_size);
 776         if (sbi->s_frag_size == 0)
 777                 goto cantfind_ext2;
 778         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
 779
 780         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 781         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 782         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 783
 784         if (EXT2_INODE_SIZE(sb) == 0)
 785                 goto cantfind_ext2;
 786         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
 787         if (sbi->s_inodes_per_block == 0)
 788                 goto cantfind_ext2;
 789         sbi->s_itb_per_group = sbi->s_inodes_per_group /
 790                                         sbi->s_inodes_per_block;
 791         sbi->s_desc_per_block = sb->s_blocksize /
 792                                         sizeof (struct ext2_group_desc);
 793         sbi->s_sbh = bh;
 794         sbi->s_mount_state = le16_to_cpu(es->s_state);
 795         sbi->s_addr_per_block_bits =
 796                 log2 (EXT2_ADDR_PER_BLOCK(sb));
 797         sbi->s_desc_per_block_bits =
 798                 log2 (EXT2_DESC_PER_BLOCK(sb));
 799
 800         if (sb->s_magic != EXT2_SUPER_MAGIC)
 801                 goto cantfind_ext2;
 802
 803         if (sb->s_blocksize != bh->b_size) {
 804                 if (!silent)
 805                         printk ("VFS: Unsupported blocksize on dev "
 806                                 "%s.\n", sb->s_id);
 807                 goto failed_mount;
 808         }
 809
 810         if (sb->s_blocksize != sbi->s_frag_size) {
 811                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
 812                         sbi->s_frag_size, sb->s_blocksize);
 813                 goto failed_mount;
 814         }
 815
 816         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
 817                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
 818                         sbi->s_blocks_per_group);
 819                 goto failed_mount;
 820         }
 821         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 822                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
 823                         sbi->s_frags_per_group);
 824                 goto failed_mount;
 825         }
 826         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
 827                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
 828                         sbi->s_inodes_per_group);
 829                 goto failed_mount;
 830         }
 831
 832         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
 833                 goto cantfind_ext2;
 834         sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) -
 835                                         le32_to_cpu(es->s_first_data_block) +
 836                                        EXT2_BLOCKS_PER_GROUP(sb) - 1) /
 837                                        EXT2_BLOCKS_PER_GROUP(sb);
 838         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
 839                    EXT2_DESC_PER_BLOCK(sb);
 840         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
 841         if (sbi->s_group_desc == NULL) {
 842                 printk ("EXT2-fs: not enough memory\n");
 843                 goto failed_mount;
 844         }
 845         percpu_counter_init(&sbi->s_freeblocks_counter);
 846         percpu_counter_init(&sbi->s_freeinodes_counter);
 847         percpu_counter_init(&sbi->s_dirs_counter);
 848         bgl_lock_init(&sbi->s_blockgroup_lock);
 849         sbi->s_debts = kmalloc(sbi->s_groups_count * sizeof(*sbi->s_debts),
 850                                GFP_KERNEL);
 851         if (!sbi->s_debts) {
 852                 printk ("EXT2-fs: not enough memory\n");
 853                 goto failed_mount_group_desc;
 854         }
 855         memset(sbi->s_debts, 0, sbi->s_groups_count * sizeof(*sbi->s_debts));
 856         for (i = 0; i < db_count; i++) {
 857                 block = descriptor_loc(sb, logic_sb_block, i);
 858                 sbi->s_group_desc[i] = sb_bread(sb, block);
 859                 if (!sbi->s_group_desc[i]) {
 860                         for (j = 0; j < i; j++)
 861                                 brelse (sbi->s_group_desc[j]);
 862                         printk ("EXT2-fs: unable to read group descriptors\n");
 863                         goto failed_mount_group_desc;
 864                 }
 865         }
 866         if (!ext2_check_descriptors (sb)) {
 867                 printk ("EXT2-fs: group descriptors corrupted!\n");
 868                 db_count = i;
 869                 goto failed_mount2;
 870         }
 871         sbi->s_gdb_count = db_count;
 872         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
 873         spin_lock_init(&sbi->s_next_gen_lock);
 874         /*
 875          * set up enough so that it can read an inode
 876          */
 877         sb->s_op = &ext2_sops;
 878         sb->s_export_op = &ext2_export_ops;
 879         sb->s_xattr = ext2_xattr_handlers;
 880         root = iget(sb, EXT2_ROOT_INO);
 881         sb->s_root = d_alloc_root(root);
 882         if (!sb->s_root) {
 883                 iput(root);
 884                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
 885                 goto failed_mount2;
 886         }
 887         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
 888                 dput(sb->s_root);
 889                 sb->s_root = NULL;
 890                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
 891                 goto failed_mount2;
 892         }
 893         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 894                 ext2_warning(sb, __FUNCTION__,
 895                         "mounting ext3 filesystem as ext2");
 896         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
 897         percpu_counter_mod(&sbi->s_freeblocks_counter,
 898                                 ext2_count_free_blocks(sb));
 899         percpu_counter_mod(&sbi->s_freeinodes_counter,
 900                                 ext2_count_free_inodes(sb));
 901         percpu_counter_mod(&sbi->s_dirs_counter,
 902                                 ext2_count_dirs(sb));
 903         return 0;
 904
 905 cantfind_ext2:
 906         if (!silent)
 907                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
 908                        sb->s_id);
 909         goto failed_mount;
 910
 911 failed_mount2:
 912         for (i = 0; i < db_count; i++)
 913                 brelse(sbi->s_group_desc[i]);
 914 failed_mount_group_desc:
 915         kfree(sbi->s_group_desc);
 916         kfree(sbi->s_debts);
 917 failed_mount:
 918         brelse(bh);
 919 failed_sbi:
 920         sb->s_fs_info = NULL;
 921         kfree(sbi);
 922         return -EINVAL;
 923 }
 924
 925 static void ext2_commit_super (struct super_block * sb,
 926                                struct ext2_super_block * es)
 927 {
 928         es->s_wtime = cpu_to_le32(get_seconds());
 929         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 930         sb->s_dirt = 0;
 931 }
 932
 933 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
 934 {
 935         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 936         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 937         es->s_wtime = cpu_to_le32(get_seconds());
 938         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 939         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
 940         sb->s_dirt = 0;
 941 }
 942
 943 /*
 944  * In the second extended file system, it is not necessary to
 945  * write the super block since we use a mapping of the
 946  * disk super block in a buffer.
 947  *
 948  * However, this function is still used to set the fs valid
 949  * flags to 0.  We need to set this flag to 0 since the fs
 950  * may have been checked while mounted and e2fsck may have
 951  * set s_state to EXT2_VALID_FS after some corrections.
 952  */
 953
 954 void ext2_write_super (struct super_block * sb)
 955 {
 956         struct ext2_super_block * es;
 957         lock_kernel();
 958         if (!(sb->s_flags & MS_RDONLY)) {
 959                 es = EXT2_SB(sb)->s_es;
 960
 961                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
 962                         ext2_debug ("setting valid to 0\n");
 963                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
 964                                                   ~EXT2_VALID_FS);
 965                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 966                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 967                         es->s_mtime = cpu_to_le32(get_seconds());
 968                         ext2_sync_super(sb, es);
 969                 } else
 970                         ext2_commit_super (sb, es);
 971         }
 972         sb->s_dirt = 0;
 973         unlock_kernel();
 974 }
 975
 976 static int ext2_remount (struct super_block * sb, int * flags, char * data)
 977 {
 978         struct ext2_sb_info * sbi = EXT2_SB(sb);
 979         struct ext2_super_block * es;
 980         unsigned long old_mount_opt = sbi->s_mount_opt;
 981         struct ext2_mount_options old_opts;
 982         unsigned long old_sb_flags;
 983         int err;
 984
 985         /* Store the old options */
 986         old_sb_flags = sb->s_flags;
 987         old_opts.s_mount_opt = sbi->s_mount_opt;
 988         old_opts.s_resuid = sbi->s_resuid;
 989         old_opts.s_resgid = sbi->s_resgid;
 990
 991         /*
 992          * Allow the "check" option to be passed as a remount option.
 993          */
 994         if (!parse_options (data, sbi)) {
 995                 err = -EINVAL;
 996                 goto restore_opts;
 997         }
 998
 999         if ((sbi->s_mount_opt & EXT2_MOUNT_TAGXID) &&
1000                 !(sb->s_flags & MS_TAGXID)) {
1001                 printk("EXT2-fs: %s: tagxid not permitted on remount.\n",
1002                        sb->s_id);
1003                 return -EINVAL;
1004         }
1005
1006         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1007                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1008
1009         es = sbi->s_es;
1010         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
1011             (old_mount_opt & EXT2_MOUNT_XIP)) &&
1012             invalidate_inodes(sb))
1013                 ext2_warning(sb, __FUNCTION__, "busy inodes while remounting "\
1014                              "xip remain in cache (no functional problem)");
1015         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1016                 return 0;
1017         if (*flags & MS_RDONLY) {
1018                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1019                     !(sbi->s_mount_state & EXT2_VALID_FS))
1020                         return 0;
1021                 /*
1022                  * OK, we are remounting a valid rw partition rdonly, so set
1023                  * the rdonly flag and then mark the partition as valid again.
1024                  */
1025                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1026                 es->s_mtime = cpu_to_le32(get_seconds());
1027         } else {
1028                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1029                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1030                 if (ret) {
1031                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
1032                                "unsupported optional features (%x).\n",
1033                                sb->s_id, le32_to_cpu(ret));
1034                         err = -EROFS;
1035                         goto restore_opts;
1036                 }
1037                 /*
1038                  * Mounting a RDONLY partition read-write, so reread and
1039                  * store the current valid flag.  (It may have been changed
1040                  * by e2fsck since we originally mounted the partition.)
1041                  */
1042                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1043                 if (!ext2_setup_super (sb, es, 0))
1044                         sb->s_flags &= ~MS_RDONLY;
1045         }
1046         ext2_sync_super(sb, es);
1047         return 0;
1048 restore_opts:
1049         sbi->s_mount_opt = old_opts.s_mount_opt;
1050         sbi->s_resuid = old_opts.s_resuid;
1051         sbi->s_resgid = old_opts.s_resgid;
1052         sb->s_flags = old_sb_flags;
1053         return err;
1054 }
1055
1056 static int ext2_statfs (struct super_block * sb, struct kstatfs * buf)
1057 {
1058         struct ext2_sb_info *sbi = EXT2_SB(sb);
1059         unsigned long overhead;
1060         int i;
1061
1062         if (test_opt (sb, MINIX_DF))
1063                 overhead = 0;
1064         else {
1065                 /*
1066                  * Compute the overhead (FS structures)
1067                  */
1068
1069                 /*
1070                  * All of the blocks before first_data_block are
1071                  * overhead
1072                  */
1073                 overhead = le32_to_cpu(sbi->s_es->s_first_data_block);
1074
1075                 /*
1076                  * Add the overhead attributed to the superblock and
1077                  * block group descriptors.  If the sparse superblocks
1078                  * feature is turned on, then not all groups have this.
1079                  */
1080                 for (i = 0; i < sbi->s_groups_count; i++)
1081                         overhead += ext2_bg_has_super(sb, i) +
1082                                 ext2_bg_num_gdb(sb, i);
1083
1084                 /*
1085                  * Every block group has an inode bitmap, a block
1086                  * bitmap, and an inode table.
1087                  */
1088                 overhead += (sbi->s_groups_count *
1089                              (2 + sbi->s_itb_per_group));
1090         }
1091
1092         buf->f_type = EXT2_SUPER_MAGIC;
1093         buf->f_bsize = sb->s_blocksize;
1094         buf->f_blocks = le32_to_cpu(sbi->s_es->s_blocks_count) - overhead;
1095         buf->f_bfree = ext2_count_free_blocks(sb);
1096         buf->f_bavail = buf->f_bfree - le32_to_cpu(sbi->s_es->s_r_blocks_count);
1097         if (buf->f_bfree < le32_to_cpu(sbi->s_es->s_r_blocks_count))
1098                 buf->f_bavail = 0;
1099         buf->f_files = le32_to_cpu(sbi->s_es->s_inodes_count);
1100         buf->f_ffree = ext2_count_free_inodes (sb);
1101         buf->f_namelen = EXT2_NAME_LEN;
1102         return 0;
1103 }
1104
1105 static struct super_block *ext2_get_sb(struct file_system_type *fs_type,
1106         int flags, const char *dev_name, void *data)
1107 {
1108         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1109 }
1110
1111 #ifdef CONFIG_QUOTA
1112
1113 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1114  * acquiring the locks... As quota files are never truncated and quota code
1115  * itself serializes the operations (and noone else should touch the files)
1116  * we don't have to be afraid of races */
1117 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1118                                size_t len, loff_t off)
1119 {
1120         struct inode *inode = sb_dqopt(sb)->files[type];
1121         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1122         int err = 0;
1123         int offset = off & (sb->s_blocksize - 1);
1124         int tocopy;
1125         size_t toread;
1126         struct buffer_head tmp_bh;
1127         struct buffer_head *bh;
1128         loff_t i_size = i_size_read(inode);
1129
1130         if (off > i_size)
1131                 return 0;
1132         if (off+len > i_size)
1133                 len = i_size-off;
1134         toread = len;
1135         while (toread > 0) {
1136                 tocopy = sb->s_blocksize - offset < toread ?
1137                                 sb->s_blocksize - offset : toread;
1138
1139                 tmp_bh.b_state = 0;
1140                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1141                 if (err)
1142                         return err;
1143                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1144                         memset(data, 0, tocopy);
1145                 else {
1146                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1147                         if (!bh)
1148                                 return -EIO;
1149                         memcpy(data, bh->b_data+offset, tocopy);
1150                         brelse(bh);
1151                 }
1152                 offset = 0;
1153                 toread -= tocopy;
1154                 data += tocopy;
1155                 blk++;
1156         }
1157         return len;
1158 }
1159
1160 /* Write to quotafile */
1161 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1162                                 const char *data, size_t len, loff_t off)
1163 {
1164         struct inode *inode = sb_dqopt(sb)->files[type];
1165         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1166         int err = 0;
1167         int offset = off & (sb->s_blocksize - 1);
1168         int tocopy;
1169         size_t towrite = len;
1170         struct buffer_head tmp_bh;
1171         struct buffer_head *bh;
1172
1173         mutex_lock(&inode->i_mutex);
1174         while (towrite > 0) {
1175                 tocopy = sb->s_blocksize - offset < towrite ?
1176                                 sb->s_blocksize - offset : towrite;
1177
1178                 tmp_bh.b_state = 0;
1179                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1180                 if (err)
1181                         goto out;
1182                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1183                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1184                 else
1185                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1186                 if (!bh) {
1187                         err = -EIO;
1188                         goto out;
1189                 }
1190                 lock_buffer(bh);
1191                 memcpy(bh->b_data+offset, data, tocopy);
1192                 flush_dcache_page(bh->b_page);
1193                 set_buffer_uptodate(bh);
1194                 mark_buffer_dirty(bh);
1195                 unlock_buffer(bh);
1196                 brelse(bh);
1197                 offset = 0;
1198                 towrite -= tocopy;
1199                 data += tocopy;
1200                 blk++;
1201         }
1202 out:
1203         if (len == towrite)
1204                 return err;
1205         if (inode->i_size < off+len-towrite)
1206                 i_size_write(inode, off+len-towrite);
1207         inode->i_version++;
1208         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1209         mark_inode_dirty(inode);
1210         mutex_unlock(&inode->i_mutex);
1211         return len - towrite;
1212 }
1213
1214 #endif
1215
1216 static struct file_system_type ext2_fs_type = {
1217         .owner          = THIS_MODULE,
1218         .name           = "ext2",
1219         .get_sb         = ext2_get_sb,
1220         .kill_sb        = kill_block_super,
1221         .fs_flags       = FS_REQUIRES_DEV,
1222 };
1223
1224 static int __init init_ext2_fs(void)
1225 {
1226         int err = init_ext2_xattr();
1227         if (err)
1228                 return err;
1229         err = init_inodecache();
1230         if (err)
1231                 goto out1;
1232         err = register_filesystem(&ext2_fs_type);
1233         if (err)
1234                 goto out;
1235         return 0;
1236 out:
1237         destroy_inodecache();
1238 out1:
1239         exit_ext2_xattr();
1240         return err;
1241 }
1242
1243 static void __exit exit_ext2_fs(void)
1244 {
1245         unregister_filesystem(&ext2_fs_type);
1246         destroy_inodecache();
1247         exit_ext2_xattr();
1248 }
1249
1250 module_init(init_ext2_fs)
1251 module_exit(exit_ext2_fs)