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                                              init_once, NULL);
 180         if (ext2_inode_cachep == NULL)
 181                 return -ENOMEM;
 182         return 0;
 183 }
 184
 185 static void destroy_inodecache(void)
 186 {
 187         if (kmem_cache_destroy(ext2_inode_cachep))
 188                 printk(KERN_INFO "ext2_inode_cache: not all structures were freed\n");
 189 }
 190
 191 static void ext2_clear_inode(struct inode *inode)
 192 {
 193 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 194         struct ext2_inode_info *ei = EXT2_I(inode);
 195
 196         if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
 197                 posix_acl_release(ei->i_acl);
 198                 ei->i_acl = EXT2_ACL_NOT_CACHED;
 199         }
 200         if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
 201                 posix_acl_release(ei->i_default_acl);
 202                 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 203         }
 204 #endif
 205 }
 206
 207 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
 208 {
 209         struct ext2_sb_info *sbi = EXT2_SB(vfs->mnt_sb);
 210
 211         if (sbi->s_mount_opt & EXT2_MOUNT_GRPID)
 212                 seq_puts(seq, ",grpid");
 213         else
 214                 seq_puts(seq, ",nogrpid");
 215
 216 #if defined(CONFIG_QUOTA)
 217         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
 218                 seq_puts(seq, ",usrquota");
 219
 220         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
 221                 seq_puts(seq, ",grpquota");
 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 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 /* Yes, most of these are left as NULL!!
 252  * A NULL value implies the default, which works with ext2-like file
 253  * systems, but can be improved upon.
 254  * Currently only get_parent is required.
 255  */
 256 struct dentry *ext2_get_parent(struct dentry *child);
 257 static struct export_operations ext2_export_ops = {
 258         .get_parent = ext2_get_parent,
 259 };
 260
 261 static unsigned long get_sb_block(void **data)
 262 {
 263         unsigned long   sb_block;
 264         char            *options = (char *) *data;
 265
 266         if (!options || strncmp(options, "sb=", 3) != 0)
 267                 return 1;       /* Default location */
 268         options += 3;
 269         sb_block = simple_strtoul(options, &options, 0);
 270         if (*options && *options != ',') {
 271                 printk("EXT2-fs: Invalid sb specification: %s\n",
 272                        (char *) *data);
 273                 return 1;
 274         }
 275         if (*options == ',')
 276                 options++;
 277         *data = (void *) options;
 278         return sb_block;
 279 }
 280
 281 enum {
 282         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
 283         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
 284         Opt_err_ro, Opt_nouid32, Opt_check, Opt_nocheck, Opt_debug,
 285         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
 286         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
 287         Opt_usrquota, Opt_grpquota
 288 };
 289
 290 static match_table_t tokens = {
 291         {Opt_bsd_df, "bsddf"},
 292         {Opt_minix_df, "minixdf"},
 293         {Opt_grpid, "grpid"},
 294         {Opt_grpid, "bsdgroups"},
 295         {Opt_nogrpid, "nogrpid"},
 296         {Opt_nogrpid, "sysvgroups"},
 297         {Opt_resgid, "resgid=%u"},
 298         {Opt_resuid, "resuid=%u"},
 299         {Opt_sb, "sb=%u"},
 300         {Opt_err_cont, "errors=continue"},
 301         {Opt_err_panic, "errors=panic"},
 302         {Opt_err_ro, "errors=remount-ro"},
 303         {Opt_nouid32, "nouid32"},
 304         {Opt_nocheck, "check=none"},
 305         {Opt_nocheck, "nocheck"},
 306         {Opt_check, "check"},
 307         {Opt_debug, "debug"},
 308         {Opt_oldalloc, "oldalloc"},
 309         {Opt_orlov, "orlov"},
 310         {Opt_nobh, "nobh"},
 311         {Opt_user_xattr, "user_xattr"},
 312         {Opt_nouser_xattr, "nouser_xattr"},
 313         {Opt_acl, "acl"},
 314         {Opt_noacl, "noacl"},
 315         {Opt_xip, "xip"},
 316         {Opt_grpquota, "grpquota"},
 317         {Opt_ignore, "noquota"},
 318         {Opt_quota, "quota"},
 319         {Opt_usrquota, "usrquota"},
 320         {Opt_err, NULL}
 321 };
 322
 323 static int parse_options (char * options,
 324                           struct ext2_sb_info *sbi)
 325 {
 326         char * p;
 327         substring_t args[MAX_OPT_ARGS];
 328         unsigned long kind = EXT2_MOUNT_ERRORS_CONT;
 329         int option;
 330
 331         if (!options)
 332                 return 1;
 333
 334         while ((p = strsep (&options, ",")) != NULL) {
 335                 int token;
 336                 if (!*p)
 337                         continue;
 338
 339                 token = match_token(p, tokens, args);
 340                 switch (token) {
 341                 case Opt_bsd_df:
 342                         clear_opt (sbi->s_mount_opt, MINIX_DF);
 343                         break;
 344                 case Opt_minix_df:
 345                         set_opt (sbi->s_mount_opt, MINIX_DF);
 346                         break;
 347                 case Opt_grpid:
 348                         set_opt (sbi->s_mount_opt, GRPID);
 349                         break;
 350                 case Opt_nogrpid:
 351                         clear_opt (sbi->s_mount_opt, GRPID);
 352                         break;
 353                 case Opt_resuid:
 354                         if (match_int(&args[0], &option))
 355                                 return 0;
 356                         sbi->s_resuid = option;
 357                         break;
 358                 case Opt_resgid:
 359                         if (match_int(&args[0], &option))
 360                                 return 0;
 361                         sbi->s_resgid = option;
 362                         break;
 363                 case Opt_sb:
 364                         /* handled by get_sb_block() instead of here */
 365                         /* *sb_block = match_int(&args[0]); */
 366                         break;
 367                 case Opt_err_panic:
 368                         kind = EXT2_MOUNT_ERRORS_PANIC;
 369                         break;
 370                 case Opt_err_ro:
 371                         kind = EXT2_MOUNT_ERRORS_RO;
 372                         break;
 373                 case Opt_err_cont:
 374                         kind = EXT2_MOUNT_ERRORS_CONT;
 375                         break;
 376                 case Opt_nouid32:
 377                         set_opt (sbi->s_mount_opt, NO_UID32);
 378                         break;
 379                 case Opt_check:
 380 #ifdef CONFIG_EXT2_CHECK
 381                         set_opt (sbi->s_mount_opt, CHECK);
 382 #else
 383                         printk("EXT2 Check option not supported\n");
 384 #endif
 385                         break;
 386                 case Opt_nocheck:
 387                         clear_opt (sbi->s_mount_opt, CHECK);
 388                         break;
 389                 case Opt_debug:
 390                         set_opt (sbi->s_mount_opt, DEBUG);
 391                         break;
 392                 case Opt_oldalloc:
 393                         set_opt (sbi->s_mount_opt, OLDALLOC);
 394                         break;
 395                 case Opt_orlov:
 396                         clear_opt (sbi->s_mount_opt, OLDALLOC);
 397                         break;
 398                 case Opt_nobh:
 399                         set_opt (sbi->s_mount_opt, NOBH);
 400                         break;
 401 #ifdef CONFIG_EXT2_FS_XATTR
 402                 case Opt_user_xattr:
 403                         set_opt (sbi->s_mount_opt, XATTR_USER);
 404                         break;
 405                 case Opt_nouser_xattr:
 406                         clear_opt (sbi->s_mount_opt, XATTR_USER);
 407                         break;
 408 #else
 409                 case Opt_user_xattr:
 410                 case Opt_nouser_xattr:
 411                         printk("EXT2 (no)user_xattr options not supported\n");
 412                         break;
 413 #endif
 414 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 415                 case Opt_acl:
 416                         set_opt(sbi->s_mount_opt, POSIX_ACL);
 417                         break;
 418                 case Opt_noacl:
 419                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
 420                         break;
 421 #else
 422                 case Opt_acl:
 423                 case Opt_noacl:
 424                         printk("EXT2 (no)acl options not supported\n");
 425                         break;
 426 #endif
 427                 case Opt_xip:
 428 #ifdef CONFIG_EXT2_FS_XIP
 429                         set_opt (sbi->s_mount_opt, XIP);
 430 #else
 431                         printk("EXT2 xip option not supported\n");
 432 #endif
 433                         break;
 434
 435 #if defined(CONFIG_QUOTA)
 436                 case Opt_quota:
 437                 case Opt_usrquota:
 438                         set_opt(sbi->s_mount_opt, USRQUOTA);
 439                         break;
 440
 441                 case Opt_grpquota:
 442                         set_opt(sbi->s_mount_opt, GRPQUOTA);
 443                         break;
 444 #else
 445                 case Opt_quota:
 446                 case Opt_usrquota:
 447                 case Opt_grpquota:
 448                         printk(KERN_ERR
 449                                 "EXT2-fs: quota operations not supported.\n");
 450
 451                         break;
 452 #endif
 453
 454                 case Opt_ignore:
 455                         break;
 456                 default:
 457                         return 0;
 458                 }
 459         }
 460         sbi->s_mount_opt |= kind;
 461         return 1;
 462 }
 463
 464 static int ext2_setup_super (struct super_block * sb,
 465                               struct ext2_super_block * es,
 466                               int read_only)
 467 {
 468         int res = 0;
 469         struct ext2_sb_info *sbi = EXT2_SB(sb);
 470
 471         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 472                 printk ("EXT2-fs warning: revision level too high, "
 473                         "forcing read-only mode\n");
 474                 res = MS_RDONLY;
 475         }
 476         if (read_only)
 477                 return res;
 478         if (!(sbi->s_mount_state & EXT2_VALID_FS))
 479                 printk ("EXT2-fs warning: mounting unchecked fs, "
 480                         "running e2fsck is recommended\n");
 481         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 482                 printk ("EXT2-fs warning: mounting fs with errors, "
 483                         "running e2fsck is recommended\n");
 484         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 485                  le16_to_cpu(es->s_mnt_count) >=
 486                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 487                 printk ("EXT2-fs warning: maximal mount count reached, "
 488                         "running e2fsck is recommended\n");
 489         else if (le32_to_cpu(es->s_checkinterval) &&
 490                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 491                 printk ("EXT2-fs warning: checktime reached, "
 492                         "running e2fsck is recommended\n");
 493         if (!le16_to_cpu(es->s_max_mnt_count))
 494                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 495         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
 496         ext2_write_super(sb);
 497         if (test_opt (sb, DEBUG))
 498                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
 499                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
 500                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 501                         sbi->s_frag_size,
 502                         sbi->s_groups_count,
 503                         EXT2_BLOCKS_PER_GROUP(sb),
 504                         EXT2_INODES_PER_GROUP(sb),
 505                         sbi->s_mount_opt);
 506 #ifdef CONFIG_EXT2_CHECK
 507         if (test_opt (sb, CHECK)) {
 508                 ext2_check_blocks_bitmap (sb);
 509                 ext2_check_inodes_bitmap (sb);
 510         }
 511 #endif
 512         return res;
 513 }
 514
 515 static int ext2_check_descriptors (struct super_block * sb)
 516 {
 517         int i;
 518         int desc_block = 0;
 519         struct ext2_sb_info *sbi = EXT2_SB(sb);
 520         unsigned long block = le32_to_cpu(sbi->s_es->s_first_data_block);
 521         struct ext2_group_desc * gdp = NULL;
 522
 523         ext2_debug ("Checking group descriptors");
 524
 525         for (i = 0; i < sbi->s_groups_count; i++)
 526         {
 527                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
 528                         gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
 529                 if (le32_to_cpu(gdp->bg_block_bitmap) < block ||
 530                     le32_to_cpu(gdp->bg_block_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 531                 {
 532                         ext2_error (sb, "ext2_check_descriptors",
 533                                     "Block bitmap for group %d"
 534                                     " not in group (block %lu)!",
 535                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 536                         return 0;
 537                 }
 538                 if (le32_to_cpu(gdp->bg_inode_bitmap) < block ||
 539                     le32_to_cpu(gdp->bg_inode_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 540                 {
 541                         ext2_error (sb, "ext2_check_descriptors",
 542                                     "Inode bitmap for group %d"
 543                                     " not in group (block %lu)!",
 544                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 545                         return 0;
 546                 }
 547                 if (le32_to_cpu(gdp->bg_inode_table) < block ||
 548                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >=
 549                     block + EXT2_BLOCKS_PER_GROUP(sb))
 550                 {
 551                         ext2_error (sb, "ext2_check_descriptors",
 552                                     "Inode table for group %d"
 553                                     " not in group (block %lu)!",
 554                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 555                         return 0;
 556                 }
 557                 block += EXT2_BLOCKS_PER_GROUP(sb);
 558                 gdp++;
 559         }
 560         return 1;
 561 }
 562
 563 #define log2(n) ffz(~(n))
 564
 565 /*
 566  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 567  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 568  * We need to be 1 filesystem block less than the 2^32 sector limit.
 569  */
 570 static loff_t ext2_max_size(int bits)
 571 {
 572         loff_t res = EXT2_NDIR_BLOCKS;
 573         /* This constant is calculated to be the largest file size for a
 574          * dense, 4k-blocksize file such that the total number of
 575          * sectors in the file, including data and all indirect blocks,
 576          * does not exceed 2^32. */
 577         const loff_t upper_limit = 0x1ff7fffd000LL;
 578
 579         res += 1LL << (bits-2);
 580         res += 1LL << (2*(bits-2));
 581         res += 1LL << (3*(bits-2));
 582         res <<= bits;
 583         if (res > upper_limit)
 584                 res = upper_limit;
 585         return res;
 586 }
 587
 588 static unsigned long descriptor_loc(struct super_block *sb,
 589                                     unsigned long logic_sb_block,
 590                                     int nr)
 591 {
 592         struct ext2_sb_info *sbi = EXT2_SB(sb);
 593         unsigned long bg, first_data_block, first_meta_bg;
 594         int has_super = 0;
 595
 596         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 597         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 598
 599         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 600             nr < first_meta_bg)
 601                 return (logic_sb_block + nr + 1);
 602         bg = sbi->s_desc_per_block * nr;
 603         if (ext2_bg_has_super(sb, bg))
 604                 has_super = 1;
 605         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
 606 }
 607
 608 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 609 {
 610         struct buffer_head * bh;
 611         struct ext2_sb_info * sbi;
 612         struct ext2_super_block * es;
 613         struct inode *root;
 614         unsigned long block;
 615         unsigned long sb_block = get_sb_block(&data);
 616         unsigned long logic_sb_block;
 617         unsigned long offset = 0;
 618         unsigned long def_mount_opts;
 619         int blocksize = BLOCK_SIZE;
 620         int db_count;
 621         int i, j;
 622         __le32 features;
 623
 624         sbi = kmalloc(sizeof(*sbi), GFP_KERNEL);
 625         if (!sbi)
 626                 return -ENOMEM;
 627         sb->s_fs_info = sbi;
 628         memset(sbi, 0, sizeof(*sbi));
 629
 630         /*
 631          * See what the current blocksize for the device is, and
 632          * use that as the blocksize.  Otherwise (or if the blocksize
 633          * is smaller than the default) use the default.
 634          * This is important for devices that have a hardware
 635          * sectorsize that is larger than the default.
 636          */
 637         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 638         if (!blocksize) {
 639                 printk ("EXT2-fs: unable to set blocksize\n");
 640                 goto failed_sbi;
 641         }
 642
 643         /*
 644          * If the superblock doesn't start on a hardware sector boundary,
 645          * calculate the offset.
 646          */
 647         if (blocksize != BLOCK_SIZE) {
 648                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 649                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 650         } else {
 651                 logic_sb_block = sb_block;
 652         }
 653
 654         if (!(bh = sb_bread(sb, logic_sb_block))) {
 655                 printk ("EXT2-fs: unable to read superblock\n");
 656                 goto failed_sbi;
 657         }
 658         /*
 659          * Note: s_es must be initialized as soon as possible because
 660          *       some ext2 macro-instructions depend on its value
 661          */
 662         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 663         sbi->s_es = es;
 664         sb->s_magic = le16_to_cpu(es->s_magic);
 665
 666         if (sb->s_magic != EXT2_SUPER_MAGIC)
 667                 goto cantfind_ext2;
 668
 669         /* Set defaults before we parse the mount options */
 670         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 671         if (def_mount_opts & EXT2_DEFM_DEBUG)
 672                 set_opt(sbi->s_mount_opt, DEBUG);
 673         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 674                 set_opt(sbi->s_mount_opt, GRPID);
 675         if (def_mount_opts & EXT2_DEFM_UID16)
 676                 set_opt(sbi->s_mount_opt, NO_UID32);
 677         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 678                 set_opt(sbi->s_mount_opt, XATTR_USER);
 679         if (def_mount_opts & EXT2_DEFM_ACL)
 680                 set_opt(sbi->s_mount_opt, POSIX_ACL);
 681
 682         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 683                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 684         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
 685                 set_opt(sbi->s_mount_opt, ERRORS_RO);
 686
 687         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
 688         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
 689
 690         if (!parse_options ((char *) data, sbi))
 691                 goto failed_mount;
 692
 693         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 694                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 695                  MS_POSIXACL : 0);
 696
 697         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
 698                                     EXT2_MOUNT_XIP if not */
 699
 700         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 701             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 702              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 703              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 704                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
 705                        "running e2fsck is recommended\n");
 706         /*
 707          * Check feature flags regardless of the revision level, since we
 708          * previously didn't change the revision level when setting the flags,
 709          * so there is a chance incompat flags are set on a rev 0 filesystem.
 710          */
 711         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 712         if (features) {
 713                 printk("EXT2-fs: %s: couldn't mount because of "
 714                        "unsupported optional features (%x).\n",
 715                        sb->s_id, le32_to_cpu(features));
 716                 goto failed_mount;
 717         }
 718         if (!(sb->s_flags & MS_RDONLY) &&
 719             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 720                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
 721                        "unsupported optional features (%x).\n",
 722                        sb->s_id, le32_to_cpu(features));
 723                 goto failed_mount;
 724         }
 725
 726         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 727
 728         if ((ext2_use_xip(sb)) && ((blocksize != PAGE_SIZE) ||
 729                                   (sb->s_blocksize != blocksize))) {
 730                 if (!silent)
 731                         printk("XIP: Unsupported blocksize\n");
 732                 goto failed_mount;
 733         }
 734
 735         /* If the blocksize doesn't match, re-read the thing.. */
 736         if (sb->s_blocksize != blocksize) {
 737                 brelse(bh);
 738
 739                 if (!sb_set_blocksize(sb, blocksize)) {
 740                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
 741                         goto failed_sbi;
 742                 }
 743
 744                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 745                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 746                 bh = sb_bread(sb, logic_sb_block);
 747                 if(!bh) {
 748                         printk("EXT2-fs: Couldn't read superblock on "
 749                                "2nd try.\n");
 750                         goto failed_sbi;
 751                 }
 752                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 753                 sbi->s_es = es;
 754                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 755                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
 756                         goto failed_mount;
 757                 }
 758         }
 759
 760         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 761
 762         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 763                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 764                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 765         } else {
 766                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 767                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 768                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 769                     (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
 770                     (sbi->s_inode_size > blocksize)) {
 771                         printk ("EXT2-fs: unsupported inode size: %d\n",
 772                                 sbi->s_inode_size);
 773                         goto failed_mount;
 774                 }
 775         }
 776
 777         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 778                                    le32_to_cpu(es->s_log_frag_size);
 779         if (sbi->s_frag_size == 0)
 780                 goto cantfind_ext2;
 781         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
 782
 783         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 784         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 785         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 786
 787         if (EXT2_INODE_SIZE(sb) == 0)
 788                 goto cantfind_ext2;
 789         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
 790         if (sbi->s_inodes_per_block == 0)
 791                 goto cantfind_ext2;
 792         sbi->s_itb_per_group = sbi->s_inodes_per_group /
 793                                         sbi->s_inodes_per_block;
 794         sbi->s_desc_per_block = sb->s_blocksize /
 795                                         sizeof (struct ext2_group_desc);
 796         sbi->s_sbh = bh;
 797         sbi->s_mount_state = le16_to_cpu(es->s_state);
 798         sbi->s_addr_per_block_bits =
 799                 log2 (EXT2_ADDR_PER_BLOCK(sb));
 800         sbi->s_desc_per_block_bits =
 801                 log2 (EXT2_DESC_PER_BLOCK(sb));
 802
 803         if (sb->s_magic != EXT2_SUPER_MAGIC)
 804                 goto cantfind_ext2;
 805
 806         if (sb->s_blocksize != bh->b_size) {
 807                 if (!silent)
 808                         printk ("VFS: Unsupported blocksize on dev "
 809                                 "%s.\n", sb->s_id);
 810                 goto failed_mount;
 811         }
 812
 813         if (sb->s_blocksize != sbi->s_frag_size) {
 814                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
 815                         sbi->s_frag_size, sb->s_blocksize);
 816                 goto failed_mount;
 817         }
 818
 819         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
 820                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
 821                         sbi->s_blocks_per_group);
 822                 goto failed_mount;
 823         }
 824         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 825                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
 826                         sbi->s_frags_per_group);
 827                 goto failed_mount;
 828         }
 829         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
 830                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
 831                         sbi->s_inodes_per_group);
 832                 goto failed_mount;
 833         }
 834
 835         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
 836                 goto cantfind_ext2;
 837         sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) -
 838                                         le32_to_cpu(es->s_first_data_block) +
 839                                        EXT2_BLOCKS_PER_GROUP(sb) - 1) /
 840                                        EXT2_BLOCKS_PER_GROUP(sb);
 841         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
 842                    EXT2_DESC_PER_BLOCK(sb);
 843         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
 844         if (sbi->s_group_desc == NULL) {
 845                 printk ("EXT2-fs: not enough memory\n");
 846                 goto failed_mount;
 847         }
 848         percpu_counter_init(&sbi->s_freeblocks_counter);
 849         percpu_counter_init(&sbi->s_freeinodes_counter);
 850         percpu_counter_init(&sbi->s_dirs_counter);
 851         bgl_lock_init(&sbi->s_blockgroup_lock);
 852         sbi->s_debts = kmalloc(sbi->s_groups_count * sizeof(*sbi->s_debts),
 853                                GFP_KERNEL);
 854         if (!sbi->s_debts) {
 855                 printk ("EXT2-fs: not enough memory\n");
 856                 goto failed_mount_group_desc;
 857         }
 858         memset(sbi->s_debts, 0, sbi->s_groups_count * sizeof(*sbi->s_debts));
 859         for (i = 0; i < db_count; i++) {
 860                 block = descriptor_loc(sb, logic_sb_block, i);
 861                 sbi->s_group_desc[i] = sb_bread(sb, block);
 862                 if (!sbi->s_group_desc[i]) {
 863                         for (j = 0; j < i; j++)
 864                                 brelse (sbi->s_group_desc[j]);
 865                         printk ("EXT2-fs: unable to read group descriptors\n");
 866                         goto failed_mount_group_desc;
 867                 }
 868         }
 869         if (!ext2_check_descriptors (sb)) {
 870                 printk ("EXT2-fs: group descriptors corrupted!\n");
 871                 db_count = i;
 872                 goto failed_mount2;
 873         }
 874         sbi->s_gdb_count = db_count;
 875         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
 876         spin_lock_init(&sbi->s_next_gen_lock);
 877         /*
 878          * set up enough so that it can read an inode
 879          */
 880         sb->s_op = &ext2_sops;
 881         sb->s_export_op = &ext2_export_ops;
 882         sb->s_xattr = ext2_xattr_handlers;
 883         root = iget(sb, EXT2_ROOT_INO);
 884         sb->s_root = d_alloc_root(root);
 885         if (!sb->s_root) {
 886                 iput(root);
 887                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
 888                 goto failed_mount2;
 889         }
 890         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
 891                 dput(sb->s_root);
 892                 sb->s_root = NULL;
 893                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
 894                 goto failed_mount2;
 895         }
 896         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 897                 ext2_warning(sb, __FUNCTION__,
 898                         "mounting ext3 filesystem as ext2\n");
 899         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
 900         percpu_counter_mod(&sbi->s_freeblocks_counter,
 901                                 ext2_count_free_blocks(sb));
 902         percpu_counter_mod(&sbi->s_freeinodes_counter,
 903                                 ext2_count_free_inodes(sb));
 904         percpu_counter_mod(&sbi->s_dirs_counter,
 905                                 ext2_count_dirs(sb));
 906         return 0;
 907
 908 cantfind_ext2:
 909         if (!silent)
 910                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
 911                        sb->s_id);
 912         goto failed_mount;
 913
 914 failed_mount2:
 915         for (i = 0; i < db_count; i++)
 916                 brelse(sbi->s_group_desc[i]);
 917 failed_mount_group_desc:
 918         kfree(sbi->s_group_desc);
 919         kfree(sbi->s_debts);
 920 failed_mount:
 921         brelse(bh);
 922 failed_sbi:
 923         sb->s_fs_info = NULL;
 924         kfree(sbi);
 925         return -EINVAL;
 926 }
 927
 928 static void ext2_commit_super (struct super_block * sb,
 929                                struct ext2_super_block * es)
 930 {
 931         es->s_wtime = cpu_to_le32(get_seconds());
 932         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 933         sb->s_dirt = 0;
 934 }
 935
 936 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
 937 {
 938         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 939         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 940         es->s_wtime = cpu_to_le32(get_seconds());
 941         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 942         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
 943         sb->s_dirt = 0;
 944 }
 945
 946 /*
 947  * In the second extended file system, it is not necessary to
 948  * write the super block since we use a mapping of the
 949  * disk super block in a buffer.
 950  *
 951  * However, this function is still used to set the fs valid
 952  * flags to 0.  We need to set this flag to 0 since the fs
 953  * may have been checked while mounted and e2fsck may have
 954  * set s_state to EXT2_VALID_FS after some corrections.
 955  */
 956
 957 void ext2_write_super (struct super_block * sb)
 958 {
 959         struct ext2_super_block * es;
 960         lock_kernel();
 961         if (!(sb->s_flags & MS_RDONLY)) {
 962                 es = EXT2_SB(sb)->s_es;
 963
 964                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
 965                         ext2_debug ("setting valid to 0\n");
 966                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
 967                                                   ~EXT2_VALID_FS);
 968                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 969                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 970                         es->s_mtime = cpu_to_le32(get_seconds());
 971                         ext2_sync_super(sb, es);
 972                 } else
 973                         ext2_commit_super (sb, es);
 974         }
 975         sb->s_dirt = 0;
 976         unlock_kernel();
 977 }
 978
 979 static int ext2_remount (struct super_block * sb, int * flags, char * data)
 980 {
 981         struct ext2_sb_info * sbi = EXT2_SB(sb);
 982         struct ext2_super_block * es;
 983         unsigned long old_mount_opt = sbi->s_mount_opt;
 984         struct ext2_mount_options old_opts;
 985         unsigned long old_sb_flags;
 986         int err;
 987
 988         /* Store the old options */
 989         old_sb_flags = sb->s_flags;
 990         old_opts.s_mount_opt = sbi->s_mount_opt;
 991         old_opts.s_resuid = sbi->s_resuid;
 992         old_opts.s_resgid = sbi->s_resgid;
 993
 994         /*
 995          * Allow the "check" option to be passed as a remount option.
 996          */
 997         if (!parse_options (data, sbi)) {
 998                 err = -EINVAL;
 999                 goto restore_opts;
1000         }
1001
1002         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1003                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1004
1005         es = sbi->s_es;
1006         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
1007             (old_mount_opt & EXT2_MOUNT_XIP)) &&
1008             invalidate_inodes(sb))
1009                 ext2_warning(sb, __FUNCTION__, "busy inodes while remounting "\
1010                              "xip remain in cache (no functional problem)");
1011         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1012                 return 0;
1013         if (*flags & MS_RDONLY) {
1014                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1015                     !(sbi->s_mount_state & EXT2_VALID_FS))
1016                         return 0;
1017                 /*
1018                  * OK, we are remounting a valid rw partition rdonly, so set
1019                  * the rdonly flag and then mark the partition as valid again.
1020                  */
1021                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1022                 es->s_mtime = cpu_to_le32(get_seconds());
1023         } else {
1024                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1025                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1026                 if (ret) {
1027                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
1028                                "unsupported optional features (%x).\n",
1029                                sb->s_id, le32_to_cpu(ret));
1030                         err = -EROFS;
1031                         goto restore_opts;
1032                 }
1033                 /*
1034                  * Mounting a RDONLY partition read-write, so reread and
1035                  * store the current valid flag.  (It may have been changed
1036                  * by e2fsck since we originally mounted the partition.)
1037                  */
1038                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1039                 if (!ext2_setup_super (sb, es, 0))
1040                         sb->s_flags &= ~MS_RDONLY;
1041         }
1042         ext2_sync_super(sb, es);
1043         return 0;
1044 restore_opts:
1045         sbi->s_mount_opt = old_opts.s_mount_opt;
1046         sbi->s_resuid = old_opts.s_resuid;
1047         sbi->s_resgid = old_opts.s_resgid;
1048         sb->s_flags = old_sb_flags;
1049         return err;
1050 }
1051
1052 static int ext2_statfs (struct super_block * sb, struct kstatfs * buf)
1053 {
1054         struct ext2_sb_info *sbi = EXT2_SB(sb);
1055         unsigned long overhead;
1056         int i;
1057
1058         if (test_opt (sb, MINIX_DF))
1059                 overhead = 0;
1060         else {
1061                 /*
1062                  * Compute the overhead (FS structures)
1063                  */
1064
1065                 /*
1066                  * All of the blocks before first_data_block are
1067                  * overhead
1068                  */
1069                 overhead = le32_to_cpu(sbi->s_es->s_first_data_block);
1070
1071                 /*
1072                  * Add the overhead attributed to the superblock and
1073                  * block group descriptors.  If the sparse superblocks
1074                  * feature is turned on, then not all groups have this.
1075                  */
1076                 for (i = 0; i < sbi->s_groups_count; i++)
1077                         overhead += ext2_bg_has_super(sb, i) +
1078                                 ext2_bg_num_gdb(sb, i);
1079
1080                 /*
1081                  * Every block group has an inode bitmap, a block
1082                  * bitmap, and an inode table.
1083                  */
1084                 overhead += (sbi->s_groups_count *
1085                              (2 + sbi->s_itb_per_group));
1086         }
1087
1088         buf->f_type = EXT2_SUPER_MAGIC;
1089         buf->f_bsize = sb->s_blocksize;
1090         buf->f_blocks = le32_to_cpu(sbi->s_es->s_blocks_count) - overhead;
1091         buf->f_bfree = ext2_count_free_blocks(sb);
1092         buf->f_bavail = buf->f_bfree - le32_to_cpu(sbi->s_es->s_r_blocks_count);
1093         if (buf->f_bfree < le32_to_cpu(sbi->s_es->s_r_blocks_count))
1094                 buf->f_bavail = 0;
1095         buf->f_files = le32_to_cpu(sbi->s_es->s_inodes_count);
1096         buf->f_ffree = ext2_count_free_inodes (sb);
1097         buf->f_namelen = EXT2_NAME_LEN;
1098         return 0;
1099 }
1100
1101 static struct super_block *ext2_get_sb(struct file_system_type *fs_type,
1102         int flags, const char *dev_name, void *data)
1103 {
1104         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1105 }
1106
1107 #ifdef CONFIG_QUOTA
1108
1109 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1110  * acquiring the locks... As quota files are never truncated and quota code
1111  * itself serializes the operations (and noone else should touch the files)
1112  * we don't have to be afraid of races */
1113 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1114                                size_t len, loff_t off)
1115 {
1116         struct inode *inode = sb_dqopt(sb)->files[type];
1117         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1118         int err = 0;
1119         int offset = off & (sb->s_blocksize - 1);
1120         int tocopy;
1121         size_t toread;
1122         struct buffer_head tmp_bh;
1123         struct buffer_head *bh;
1124         loff_t i_size = i_size_read(inode);
1125
1126         if (off > i_size)
1127                 return 0;
1128         if (off+len > i_size)
1129                 len = i_size-off;
1130         toread = len;
1131         while (toread > 0) {
1132                 tocopy = sb->s_blocksize - offset < toread ?
1133                                 sb->s_blocksize - offset : toread;
1134
1135                 tmp_bh.b_state = 0;
1136                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1137                 if (err)
1138                         return err;
1139                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1140                         memset(data, 0, tocopy);
1141                 else {
1142                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1143                         if (!bh)
1144                                 return -EIO;
1145                         memcpy(data, bh->b_data+offset, tocopy);
1146                         brelse(bh);
1147                 }
1148                 offset = 0;
1149                 toread -= tocopy;
1150                 data += tocopy;
1151                 blk++;
1152         }
1153         return len;
1154 }
1155
1156 /* Write to quotafile */
1157 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1158                                 const char *data, size_t len, loff_t off)
1159 {
1160         struct inode *inode = sb_dqopt(sb)->files[type];
1161         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1162         int err = 0;
1163         int offset = off & (sb->s_blocksize - 1);
1164         int tocopy;
1165         size_t towrite = len;
1166         struct buffer_head tmp_bh;
1167         struct buffer_head *bh;
1168
1169         down(&inode->i_sem);
1170         while (towrite > 0) {
1171                 tocopy = sb->s_blocksize - offset < towrite ?
1172                                 sb->s_blocksize - offset : towrite;
1173
1174                 tmp_bh.b_state = 0;
1175                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1176                 if (err)
1177                         goto out;
1178                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1179                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1180                 else
1181                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1182                 if (!bh) {
1183                         err = -EIO;
1184                         goto out;
1185                 }
1186                 lock_buffer(bh);
1187                 memcpy(bh->b_data+offset, data, tocopy);
1188                 flush_dcache_page(bh->b_page);
1189                 set_buffer_uptodate(bh);
1190                 mark_buffer_dirty(bh);
1191                 unlock_buffer(bh);
1192                 brelse(bh);
1193                 offset = 0;
1194                 towrite -= tocopy;
1195                 data += tocopy;
1196                 blk++;
1197         }
1198 out:
1199         if (len == towrite)
1200                 return err;
1201         if (inode->i_size < off+len-towrite)
1202                 i_size_write(inode, off+len-towrite);
1203         inode->i_version++;
1204         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1205         mark_inode_dirty(inode);
1206         up(&inode->i_sem);
1207         return len - towrite;
1208 }
1209
1210 #endif
1211
1212 static struct file_system_type ext2_fs_type = {
1213         .owner          = THIS_MODULE,
1214         .name           = "ext2",
1215         .get_sb         = ext2_get_sb,
1216         .kill_sb        = kill_block_super,
1217         .fs_flags       = FS_REQUIRES_DEV,
1218 };
1219
1220 static int __init init_ext2_fs(void)
1221 {
1222         int err = init_ext2_xattr();
1223         if (err)
1224                 return err;
1225         err = init_inodecache();
1226         if (err)
1227                 goto out1;
1228         err = register_filesystem(&ext2_fs_type);
1229         if (err)
1230                 goto out;
1231         return 0;
1232 out:
1233         destroy_inodecache();
1234 out1:
1235         exit_ext2_xattr();
1236         return err;
1237 }
1238
1239 static void __exit exit_ext2_fs(void)
1240 {
1241         unregister_filesystem(&ext2_fs_type);
1242         destroy_inodecache();
1243         exit_ext2_xattr();
1244 }
1245
1246 module_init(init_ext2_fs)
1247 module_exit(exit_ext2_fs)