git.oblomov.eu Git - linux-2.6/blob - fs/ext2/super.c

   1 /*
   2  *  linux/fs/ext2/super.c
   3  *
   4  * Copyright (C) 1992, 1993, 1994, 1995
   5  * Remy Card (card@masi.ibp.fr)
   6  * Laboratoire MASI - Institut Blaise Pascal
   7  * Universite Pierre et Marie Curie (Paris VI)
   8  *
   9  *  from
  10  *
  11  *  linux/fs/minix/inode.c
  12  *
  13  *  Copyright (C) 1991, 1992  Linus Torvalds
  14  *
  15  *  Big-endian to little-endian byte-swapping/bitmaps by
  16  *        David S. Miller (davem@caip.rutgers.edu), 1995
  17  */
  18
  19 #include <linux/module.h>
  20 #include <linux/string.h>
  21 #include <linux/fs.h>
  22 #include <linux/slab.h>
  23 #include <linux/init.h>
  24 #include <linux/blkdev.h>
  25 #include <linux/parser.h>
  26 #include <linux/random.h>
  27 #include <linux/buffer_head.h>
  28 #include <linux/exportfs.h>
  29 #include <linux/smp_lock.h>
  30 #include <linux/vfs.h>
  31 #include <linux/seq_file.h>
  32 #include <linux/mount.h>
  33 #include <linux/log2.h>
  34 #include <asm/uaccess.h>
  35 #include "ext2.h"
  36 #include "xattr.h"
  37 #include "acl.h"
  38 #include "xip.h"
  39
  40 static void ext2_sync_super(struct super_block *sb,
  41                             struct ext2_super_block *es);
  42 static int ext2_remount (struct super_block * sb, int * flags, char * data);
  43 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
  44
  45 void ext2_error (struct super_block * sb, const char * function,
  46                  const char * fmt, ...)
  47 {
  48         va_list args;
  49         struct ext2_sb_info *sbi = EXT2_SB(sb);
  50         struct ext2_super_block *es = sbi->s_es;
  51
  52         if (!(sb->s_flags & MS_RDONLY)) {
  53                 sbi->s_mount_state |= EXT2_ERROR_FS;
  54                 es->s_state =
  55                         cpu_to_le16(le16_to_cpu(es->s_state) | EXT2_ERROR_FS);
  56                 ext2_sync_super(sb, es);
  57         }
  58
  59         va_start(args, fmt);
  60         printk(KERN_CRIT "EXT2-fs error (device %s): %s: ",sb->s_id, function);
  61         vprintk(fmt, args);
  62         printk("\n");
  63         va_end(args);
  64
  65         if (test_opt(sb, ERRORS_PANIC))
  66                 panic("EXT2-fs panic from previous error\n");
  67         if (test_opt(sb, ERRORS_RO)) {
  68                 printk("Remounting filesystem read-only\n");
  69                 sb->s_flags |= MS_RDONLY;
  70         }
  71 }
  72
  73 void ext2_warning (struct super_block * sb, const char * function,
  74                    const char * fmt, ...)
  75 {
  76         va_list args;
  77
  78         va_start(args, fmt);
  79         printk(KERN_WARNING "EXT2-fs warning (device %s): %s: ",
  80                sb->s_id, function);
  81         vprintk(fmt, args);
  82         printk("\n");
  83         va_end(args);
  84 }
  85
  86 void ext2_update_dynamic_rev(struct super_block *sb)
  87 {
  88         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
  89
  90         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
  91                 return;
  92
  93         ext2_warning(sb, __FUNCTION__,
  94                      "updating to rev %d because of new feature flag, "
  95                      "running e2fsck is recommended",
  96                      EXT2_DYNAMIC_REV);
  97
  98         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
  99         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
 100         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
 101         /* leave es->s_feature_*compat flags alone */
 102         /* es->s_uuid will be set by e2fsck if empty */
 103
 104         /*
 105          * The rest of the superblock fields should be zero, and if not it
 106          * means they are likely already in use, so leave them alone.  We
 107          * can leave it up to e2fsck to clean up any inconsistencies there.
 108          */
 109 }
 110
 111 static void ext2_put_super (struct super_block * sb)
 112 {
 113         int db_count;
 114         int i;
 115         struct ext2_sb_info *sbi = EXT2_SB(sb);
 116
 117         ext2_xattr_put_super(sb);
 118         if (!(sb->s_flags & MS_RDONLY)) {
 119                 struct ext2_super_block *es = sbi->s_es;
 120
 121                 es->s_state = cpu_to_le16(sbi->s_mount_state);
 122                 ext2_sync_super(sb, es);
 123         }
 124         db_count = sbi->s_gdb_count;
 125         for (i = 0; i < db_count; i++)
 126                 if (sbi->s_group_desc[i])
 127                         brelse (sbi->s_group_desc[i]);
 128         kfree(sbi->s_group_desc);
 129         kfree(sbi->s_debts);
 130         percpu_counter_destroy(&sbi->s_freeblocks_counter);
 131         percpu_counter_destroy(&sbi->s_freeinodes_counter);
 132         percpu_counter_destroy(&sbi->s_dirs_counter);
 133         brelse (sbi->s_sbh);
 134         sb->s_fs_info = NULL;
 135         kfree(sbi);
 136
 137         return;
 138 }
 139
 140 static struct kmem_cache * ext2_inode_cachep;
 141
 142 static struct inode *ext2_alloc_inode(struct super_block *sb)
 143 {
 144         struct ext2_inode_info *ei;
 145         ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
 146         if (!ei)
 147                 return NULL;
 148 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 149         ei->i_acl = EXT2_ACL_NOT_CACHED;
 150         ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 151 #endif
 152         ei->vfs_inode.i_version = 1;
 153         return &ei->vfs_inode;
 154 }
 155
 156 static void ext2_destroy_inode(struct inode *inode)
 157 {
 158         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
 159 }
 160
 161 static void init_once(struct kmem_cache * cachep, void *foo)
 162 {
 163         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
 164
 165         rwlock_init(&ei->i_meta_lock);
 166 #ifdef CONFIG_EXT2_FS_XATTR
 167         init_rwsem(&ei->xattr_sem);
 168 #endif
 169         inode_init_once(&ei->vfs_inode);
 170 }
 171
 172 static int init_inodecache(void)
 173 {
 174         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
 175                                              sizeof(struct ext2_inode_info),
 176                                              0, (SLAB_RECLAIM_ACCOUNT|
 177                                                 SLAB_MEM_SPREAD),
 178                                              init_once);
 179         if (ext2_inode_cachep == NULL)
 180                 return -ENOMEM;
 181         return 0;
 182 }
 183
 184 static void destroy_inodecache(void)
 185 {
 186         kmem_cache_destroy(ext2_inode_cachep);
 187 }
 188
 189 static void ext2_clear_inode(struct inode *inode)
 190 {
 191 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 192         struct ext2_inode_info *ei = EXT2_I(inode);
 193
 194         if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
 195                 posix_acl_release(ei->i_acl);
 196                 ei->i_acl = EXT2_ACL_NOT_CACHED;
 197         }
 198         if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
 199                 posix_acl_release(ei->i_default_acl);
 200                 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 201         }
 202 #endif
 203 }
 204
 205 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
 206 {
 207         struct super_block *sb = vfs->mnt_sb;
 208         struct ext2_sb_info *sbi = EXT2_SB(sb);
 209         struct ext2_super_block *es = sbi->s_es;
 210         unsigned long def_mount_opts;
 211
 212         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 213
 214         if (sbi->s_sb_block != 1)
 215                 seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
 216         if (test_opt(sb, MINIX_DF))
 217                 seq_puts(seq, ",minixdf");
 218         if (test_opt(sb, GRPID))
 219                 seq_puts(seq, ",grpid");
 220         if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
 221                 seq_puts(seq, ",nogrpid");
 222         if (sbi->s_resuid != EXT2_DEF_RESUID ||
 223             le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
 224                 seq_printf(seq, ",resuid=%u", sbi->s_resuid);
 225         }
 226         if (sbi->s_resgid != EXT2_DEF_RESGID ||
 227             le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
 228                 seq_printf(seq, ",resgid=%u", sbi->s_resgid);
 229         }
 230         if (test_opt(sb, ERRORS_CONT)) {
 231                 int def_errors = le16_to_cpu(es->s_errors);
 232
 233                 if (def_errors == EXT2_ERRORS_PANIC ||
 234                     def_errors == EXT2_ERRORS_RO) {
 235                         seq_puts(seq, ",errors=continue");
 236                 }
 237         }
 238         if (test_opt(sb, ERRORS_RO))
 239                 seq_puts(seq, ",errors=remount-ro");
 240         if (test_opt(sb, ERRORS_PANIC))
 241                 seq_puts(seq, ",errors=panic");
 242         if (test_opt(sb, NO_UID32))
 243                 seq_puts(seq, ",nouid32");
 244         if (test_opt(sb, DEBUG))
 245                 seq_puts(seq, ",debug");
 246         if (test_opt(sb, OLDALLOC))
 247                 seq_puts(seq, ",oldalloc");
 248
 249 #ifdef CONFIG_EXT2_FS_XATTR
 250         if (test_opt(sb, XATTR_USER))
 251                 seq_puts(seq, ",user_xattr");
 252         if (!test_opt(sb, XATTR_USER) &&
 253             (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
 254                 seq_puts(seq, ",nouser_xattr");
 255         }
 256 #endif
 257
 258 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 259         if (test_opt(sb, POSIX_ACL))
 260                 seq_puts(seq, ",acl");
 261         if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
 262                 seq_puts(seq, ",noacl");
 263 #endif
 264
 265         if (test_opt(sb, NOBH))
 266                 seq_puts(seq, ",nobh");
 267
 268 #if defined(CONFIG_QUOTA)
 269         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
 270                 seq_puts(seq, ",usrquota");
 271
 272         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
 273                 seq_puts(seq, ",grpquota");
 274 #endif
 275
 276 #if defined(CONFIG_EXT2_FS_XIP)
 277         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
 278                 seq_puts(seq, ",xip");
 279 #endif
 280
 281         return 0;
 282 }
 283
 284 #ifdef CONFIG_QUOTA
 285 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
 286 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
 287 #endif
 288
 289 static const struct super_operations ext2_sops = {
 290         .alloc_inode    = ext2_alloc_inode,
 291         .destroy_inode  = ext2_destroy_inode,
 292         .read_inode     = ext2_read_inode,
 293         .write_inode    = ext2_write_inode,
 294         .put_inode      = ext2_put_inode,
 295         .delete_inode   = ext2_delete_inode,
 296         .put_super      = ext2_put_super,
 297         .write_super    = ext2_write_super,
 298         .statfs         = ext2_statfs,
 299         .remount_fs     = ext2_remount,
 300         .clear_inode    = ext2_clear_inode,
 301         .show_options   = ext2_show_options,
 302 #ifdef CONFIG_QUOTA
 303         .quota_read     = ext2_quota_read,
 304         .quota_write    = ext2_quota_write,
 305 #endif
 306 };
 307
 308 static struct dentry *ext2_get_dentry(struct super_block *sb, void *vobjp)
 309 {
 310         __u32 *objp = vobjp;
 311         unsigned long ino = objp[0];
 312         __u32 generation = objp[1];
 313         struct inode *inode;
 314         struct dentry *result;
 315
 316         if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
 317                 return ERR_PTR(-ESTALE);
 318         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
 319                 return ERR_PTR(-ESTALE);
 320
 321         /* iget isn't really right if the inode is currently unallocated!!
 322          * ext2_read_inode currently does appropriate checks, but
 323          * it might be "neater" to call ext2_get_inode first and check
 324          * if the inode is valid.....
 325          */
 326         inode = iget(sb, ino);
 327         if (inode == NULL)
 328                 return ERR_PTR(-ENOMEM);
 329         if (is_bad_inode(inode) ||
 330             (generation && inode->i_generation != generation)) {
 331                 /* we didn't find the right inode.. */
 332                 iput(inode);
 333                 return ERR_PTR(-ESTALE);
 334         }
 335         /* now to find a dentry.
 336          * If possible, get a well-connected one
 337          */
 338         result = d_alloc_anon(inode);
 339         if (!result) {
 340                 iput(inode);
 341                 return ERR_PTR(-ENOMEM);
 342         }
 343         return result;
 344 }
 345
 346 /* Yes, most of these are left as NULL!!
 347  * A NULL value implies the default, which works with ext2-like file
 348  * systems, but can be improved upon.
 349  * Currently only get_parent is required.
 350  */
 351 static struct export_operations ext2_export_ops = {
 352         .get_parent = ext2_get_parent,
 353         .get_dentry = ext2_get_dentry,
 354 };
 355
 356 static unsigned long get_sb_block(void **data)
 357 {
 358         unsigned long   sb_block;
 359         char            *options = (char *) *data;
 360
 361         if (!options || strncmp(options, "sb=", 3) != 0)
 362                 return 1;       /* Default location */
 363         options += 3;
 364         sb_block = simple_strtoul(options, &options, 0);
 365         if (*options && *options != ',') {
 366                 printk("EXT2-fs: Invalid sb specification: %s\n",
 367                        (char *) *data);
 368                 return 1;
 369         }
 370         if (*options == ',')
 371                 options++;
 372         *data = (void *) options;
 373         return sb_block;
 374 }
 375
 376 enum {
 377         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
 378         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
 379         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
 380         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
 381         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
 382         Opt_usrquota, Opt_grpquota
 383 };
 384
 385 static match_table_t tokens = {
 386         {Opt_bsd_df, "bsddf"},
 387         {Opt_minix_df, "minixdf"},
 388         {Opt_grpid, "grpid"},
 389         {Opt_grpid, "bsdgroups"},
 390         {Opt_nogrpid, "nogrpid"},
 391         {Opt_nogrpid, "sysvgroups"},
 392         {Opt_resgid, "resgid=%u"},
 393         {Opt_resuid, "resuid=%u"},
 394         {Opt_sb, "sb=%u"},
 395         {Opt_err_cont, "errors=continue"},
 396         {Opt_err_panic, "errors=panic"},
 397         {Opt_err_ro, "errors=remount-ro"},
 398         {Opt_nouid32, "nouid32"},
 399         {Opt_nocheck, "check=none"},
 400         {Opt_nocheck, "nocheck"},
 401         {Opt_debug, "debug"},
 402         {Opt_oldalloc, "oldalloc"},
 403         {Opt_orlov, "orlov"},
 404         {Opt_nobh, "nobh"},
 405         {Opt_user_xattr, "user_xattr"},
 406         {Opt_nouser_xattr, "nouser_xattr"},
 407         {Opt_acl, "acl"},
 408         {Opt_noacl, "noacl"},
 409         {Opt_xip, "xip"},
 410         {Opt_grpquota, "grpquota"},
 411         {Opt_ignore, "noquota"},
 412         {Opt_quota, "quota"},
 413         {Opt_usrquota, "usrquota"},
 414         {Opt_err, NULL}
 415 };
 416
 417 static int parse_options (char * options,
 418                           struct ext2_sb_info *sbi)
 419 {
 420         char * p;
 421         substring_t args[MAX_OPT_ARGS];
 422         int option;
 423
 424         if (!options)
 425                 return 1;
 426
 427         while ((p = strsep (&options, ",")) != NULL) {
 428                 int token;
 429                 if (!*p)
 430                         continue;
 431
 432                 token = match_token(p, tokens, args);
 433                 switch (token) {
 434                 case Opt_bsd_df:
 435                         clear_opt (sbi->s_mount_opt, MINIX_DF);
 436                         break;
 437                 case Opt_minix_df:
 438                         set_opt (sbi->s_mount_opt, MINIX_DF);
 439                         break;
 440                 case Opt_grpid:
 441                         set_opt (sbi->s_mount_opt, GRPID);
 442                         break;
 443                 case Opt_nogrpid:
 444                         clear_opt (sbi->s_mount_opt, GRPID);
 445                         break;
 446                 case Opt_resuid:
 447                         if (match_int(&args[0], &option))
 448                                 return 0;
 449                         sbi->s_resuid = option;
 450                         break;
 451                 case Opt_resgid:
 452                         if (match_int(&args[0], &option))
 453                                 return 0;
 454                         sbi->s_resgid = option;
 455                         break;
 456                 case Opt_sb:
 457                         /* handled by get_sb_block() instead of here */
 458                         /* *sb_block = match_int(&args[0]); */
 459                         break;
 460                 case Opt_err_panic:
 461                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 462                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
 463                         set_opt (sbi->s_mount_opt, ERRORS_PANIC);
 464                         break;
 465                 case Opt_err_ro:
 466                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 467                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 468                         set_opt (sbi->s_mount_opt, ERRORS_RO);
 469                         break;
 470                 case Opt_err_cont:
 471                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
 472                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 473                         set_opt (sbi->s_mount_opt, ERRORS_CONT);
 474                         break;
 475                 case Opt_nouid32:
 476                         set_opt (sbi->s_mount_opt, NO_UID32);
 477                         break;
 478                 case Opt_nocheck:
 479                         clear_opt (sbi->s_mount_opt, CHECK);
 480                         break;
 481                 case Opt_debug:
 482                         set_opt (sbi->s_mount_opt, DEBUG);
 483                         break;
 484                 case Opt_oldalloc:
 485                         set_opt (sbi->s_mount_opt, OLDALLOC);
 486                         break;
 487                 case Opt_orlov:
 488                         clear_opt (sbi->s_mount_opt, OLDALLOC);
 489                         break;
 490                 case Opt_nobh:
 491                         set_opt (sbi->s_mount_opt, NOBH);
 492                         break;
 493 #ifdef CONFIG_EXT2_FS_XATTR
 494                 case Opt_user_xattr:
 495                         set_opt (sbi->s_mount_opt, XATTR_USER);
 496                         break;
 497                 case Opt_nouser_xattr:
 498                         clear_opt (sbi->s_mount_opt, XATTR_USER);
 499                         break;
 500 #else
 501                 case Opt_user_xattr:
 502                 case Opt_nouser_xattr:
 503                         printk("EXT2 (no)user_xattr options not supported\n");
 504                         break;
 505 #endif
 506 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 507                 case Opt_acl:
 508                         set_opt(sbi->s_mount_opt, POSIX_ACL);
 509                         break;
 510                 case Opt_noacl:
 511                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
 512                         break;
 513 #else
 514                 case Opt_acl:
 515                 case Opt_noacl:
 516                         printk("EXT2 (no)acl options not supported\n");
 517                         break;
 518 #endif
 519                 case Opt_xip:
 520 #ifdef CONFIG_EXT2_FS_XIP
 521                         set_opt (sbi->s_mount_opt, XIP);
 522 #else
 523                         printk("EXT2 xip option not supported\n");
 524 #endif
 525                         break;
 526
 527 #if defined(CONFIG_QUOTA)
 528                 case Opt_quota:
 529                 case Opt_usrquota:
 530                         set_opt(sbi->s_mount_opt, USRQUOTA);
 531                         break;
 532
 533                 case Opt_grpquota:
 534                         set_opt(sbi->s_mount_opt, GRPQUOTA);
 535                         break;
 536 #else
 537                 case Opt_quota:
 538                 case Opt_usrquota:
 539                 case Opt_grpquota:
 540                         printk(KERN_ERR
 541                                 "EXT2-fs: quota operations not supported.\n");
 542
 543                         break;
 544 #endif
 545
 546                 case Opt_ignore:
 547                         break;
 548                 default:
 549                         return 0;
 550                 }
 551         }
 552         return 1;
 553 }
 554
 555 static int ext2_setup_super (struct super_block * sb,
 556                               struct ext2_super_block * es,
 557                               int read_only)
 558 {
 559         int res = 0;
 560         struct ext2_sb_info *sbi = EXT2_SB(sb);
 561
 562         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 563                 printk ("EXT2-fs warning: revision level too high, "
 564                         "forcing read-only mode\n");
 565                 res = MS_RDONLY;
 566         }
 567         if (read_only)
 568                 return res;
 569         if (!(sbi->s_mount_state & EXT2_VALID_FS))
 570                 printk ("EXT2-fs warning: mounting unchecked fs, "
 571                         "running e2fsck is recommended\n");
 572         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 573                 printk ("EXT2-fs warning: mounting fs with errors, "
 574                         "running e2fsck is recommended\n");
 575         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 576                  le16_to_cpu(es->s_mnt_count) >=
 577                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 578                 printk ("EXT2-fs warning: maximal mount count reached, "
 579                         "running e2fsck is recommended\n");
 580         else if (le32_to_cpu(es->s_checkinterval) &&
 581                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 582                 printk ("EXT2-fs warning: checktime reached, "
 583                         "running e2fsck is recommended\n");
 584         if (!le16_to_cpu(es->s_max_mnt_count))
 585                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 586         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
 587         ext2_write_super(sb);
 588         if (test_opt (sb, DEBUG))
 589                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
 590                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
 591                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 592                         sbi->s_frag_size,
 593                         sbi->s_groups_count,
 594                         EXT2_BLOCKS_PER_GROUP(sb),
 595                         EXT2_INODES_PER_GROUP(sb),
 596                         sbi->s_mount_opt);
 597         return res;
 598 }
 599
 600 static int ext2_check_descriptors (struct super_block * sb)
 601 {
 602         int i;
 603         int desc_block = 0;
 604         struct ext2_sb_info *sbi = EXT2_SB(sb);
 605         unsigned long first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 606         unsigned long last_block;
 607         struct ext2_group_desc * gdp = NULL;
 608
 609         ext2_debug ("Checking group descriptors");
 610
 611         for (i = 0; i < sbi->s_groups_count; i++)
 612         {
 613                 if (i == sbi->s_groups_count - 1)
 614                         last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
 615                 else
 616                         last_block = first_block +
 617                                 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
 618
 619                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
 620                         gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
 621                 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
 622                     le32_to_cpu(gdp->bg_block_bitmap) > last_block)
 623                 {
 624                         ext2_error (sb, "ext2_check_descriptors",
 625                                     "Block bitmap for group %d"
 626                                     " not in group (block %lu)!",
 627                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 628                         return 0;
 629                 }
 630                 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
 631                     le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
 632                 {
 633                         ext2_error (sb, "ext2_check_descriptors",
 634                                     "Inode bitmap for group %d"
 635                                     " not in group (block %lu)!",
 636                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 637                         return 0;
 638                 }
 639                 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
 640                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
 641                     last_block)
 642                 {
 643                         ext2_error (sb, "ext2_check_descriptors",
 644                                     "Inode table for group %d"
 645                                     " not in group (block %lu)!",
 646                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 647                         return 0;
 648                 }
 649                 first_block += EXT2_BLOCKS_PER_GROUP(sb);
 650                 gdp++;
 651         }
 652         return 1;
 653 }
 654
 655 /*
 656  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 657  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 658  * We need to be 1 filesystem block less than the 2^32 sector limit.
 659  */
 660 static loff_t ext2_max_size(int bits)
 661 {
 662         loff_t res = EXT2_NDIR_BLOCKS;
 663         /* This constant is calculated to be the largest file size for a
 664          * dense, 4k-blocksize file such that the total number of
 665          * sectors in the file, including data and all indirect blocks,
 666          * does not exceed 2^32. */
 667         const loff_t upper_limit = 0x1ff7fffd000LL;
 668
 669         res += 1LL << (bits-2);
 670         res += 1LL << (2*(bits-2));
 671         res += 1LL << (3*(bits-2));
 672         res <<= bits;
 673         if (res > upper_limit)
 674                 res = upper_limit;
 675         return res;
 676 }
 677
 678 static unsigned long descriptor_loc(struct super_block *sb,
 679                                     unsigned long logic_sb_block,
 680                                     int nr)
 681 {
 682         struct ext2_sb_info *sbi = EXT2_SB(sb);
 683         unsigned long bg, first_data_block, first_meta_bg;
 684         int has_super = 0;
 685
 686         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 687         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 688
 689         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 690             nr < first_meta_bg)
 691                 return (logic_sb_block + nr + 1);
 692         bg = sbi->s_desc_per_block * nr;
 693         if (ext2_bg_has_super(sb, bg))
 694                 has_super = 1;
 695         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
 696 }
 697
 698 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 699 {
 700         struct buffer_head * bh;
 701         struct ext2_sb_info * sbi;
 702         struct ext2_super_block * es;
 703         struct inode *root;
 704         unsigned long block;
 705         unsigned long sb_block = get_sb_block(&data);
 706         unsigned long logic_sb_block;
 707         unsigned long offset = 0;
 708         unsigned long def_mount_opts;
 709         int blocksize = BLOCK_SIZE;
 710         int db_count;
 711         int i, j;
 712         __le32 features;
 713         int err;
 714
 715         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 716         if (!sbi)
 717                 return -ENOMEM;
 718         sb->s_fs_info = sbi;
 719         sbi->s_sb_block = sb_block;
 720
 721         /*
 722          * See what the current blocksize for the device is, and
 723          * use that as the blocksize.  Otherwise (or if the blocksize
 724          * is smaller than the default) use the default.
 725          * This is important for devices that have a hardware
 726          * sectorsize that is larger than the default.
 727          */
 728         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 729         if (!blocksize) {
 730                 printk ("EXT2-fs: unable to set blocksize\n");
 731                 goto failed_sbi;
 732         }
 733
 734         /*
 735          * If the superblock doesn't start on a hardware sector boundary,
 736          * calculate the offset.
 737          */
 738         if (blocksize != BLOCK_SIZE) {
 739                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 740                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 741         } else {
 742                 logic_sb_block = sb_block;
 743         }
 744
 745         if (!(bh = sb_bread(sb, logic_sb_block))) {
 746                 printk ("EXT2-fs: unable to read superblock\n");
 747                 goto failed_sbi;
 748         }
 749         /*
 750          * Note: s_es must be initialized as soon as possible because
 751          *       some ext2 macro-instructions depend on its value
 752          */
 753         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 754         sbi->s_es = es;
 755         sb->s_magic = le16_to_cpu(es->s_magic);
 756
 757         if (sb->s_magic != EXT2_SUPER_MAGIC)
 758                 goto cantfind_ext2;
 759
 760         /* Set defaults before we parse the mount options */
 761         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 762         if (def_mount_opts & EXT2_DEFM_DEBUG)
 763                 set_opt(sbi->s_mount_opt, DEBUG);
 764         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 765                 set_opt(sbi->s_mount_opt, GRPID);
 766         if (def_mount_opts & EXT2_DEFM_UID16)
 767                 set_opt(sbi->s_mount_opt, NO_UID32);
 768 #ifdef CONFIG_EXT2_FS_XATTR
 769         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 770                 set_opt(sbi->s_mount_opt, XATTR_USER);
 771 #endif
 772 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 773         if (def_mount_opts & EXT2_DEFM_ACL)
 774                 set_opt(sbi->s_mount_opt, POSIX_ACL);
 775 #endif
 776
 777         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 778                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 779         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
 780                 set_opt(sbi->s_mount_opt, ERRORS_RO);
 781         else
 782                 set_opt(sbi->s_mount_opt, ERRORS_CONT);
 783
 784         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
 785         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
 786
 787         if (!parse_options ((char *) data, sbi))
 788                 goto failed_mount;
 789
 790         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 791                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 792                  MS_POSIXACL : 0);
 793
 794         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
 795                                     EXT2_MOUNT_XIP if not */
 796
 797         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 798             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 799              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 800              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 801                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
 802                        "running e2fsck is recommended\n");
 803         /*
 804          * Check feature flags regardless of the revision level, since we
 805          * previously didn't change the revision level when setting the flags,
 806          * so there is a chance incompat flags are set on a rev 0 filesystem.
 807          */
 808         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 809         if (features) {
 810                 printk("EXT2-fs: %s: couldn't mount because of "
 811                        "unsupported optional features (%x).\n",
 812                        sb->s_id, le32_to_cpu(features));
 813                 goto failed_mount;
 814         }
 815         if (!(sb->s_flags & MS_RDONLY) &&
 816             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 817                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
 818                        "unsupported optional features (%x).\n",
 819                        sb->s_id, le32_to_cpu(features));
 820                 goto failed_mount;
 821         }
 822
 823         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 824
 825         if ((ext2_use_xip(sb)) && ((blocksize != PAGE_SIZE) ||
 826                                   (sb->s_blocksize != blocksize))) {
 827                 if (!silent)
 828                         printk("XIP: Unsupported blocksize\n");
 829                 goto failed_mount;
 830         }
 831
 832         /* If the blocksize doesn't match, re-read the thing.. */
 833         if (sb->s_blocksize != blocksize) {
 834                 brelse(bh);
 835
 836                 if (!sb_set_blocksize(sb, blocksize)) {
 837                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
 838                         goto failed_sbi;
 839                 }
 840
 841                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 842                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 843                 bh = sb_bread(sb, logic_sb_block);
 844                 if(!bh) {
 845                         printk("EXT2-fs: Couldn't read superblock on "
 846                                "2nd try.\n");
 847                         goto failed_sbi;
 848                 }
 849                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 850                 sbi->s_es = es;
 851                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 852                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
 853                         goto failed_mount;
 854                 }
 855         }
 856
 857         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 858
 859         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 860                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 861                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 862         } else {
 863                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 864                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 865                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 866                     !is_power_of_2(sbi->s_inode_size) ||
 867                     (sbi->s_inode_size > blocksize)) {
 868                         printk ("EXT2-fs: unsupported inode size: %d\n",
 869                                 sbi->s_inode_size);
 870                         goto failed_mount;
 871                 }
 872         }
 873
 874         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 875                                    le32_to_cpu(es->s_log_frag_size);
 876         if (sbi->s_frag_size == 0)
 877                 goto cantfind_ext2;
 878         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
 879
 880         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 881         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 882         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 883
 884         if (EXT2_INODE_SIZE(sb) == 0)
 885                 goto cantfind_ext2;
 886         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
 887         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
 888                 goto cantfind_ext2;
 889         sbi->s_itb_per_group = sbi->s_inodes_per_group /
 890                                         sbi->s_inodes_per_block;
 891         sbi->s_desc_per_block = sb->s_blocksize /
 892                                         sizeof (struct ext2_group_desc);
 893         sbi->s_sbh = bh;
 894         sbi->s_mount_state = le16_to_cpu(es->s_state);
 895         sbi->s_addr_per_block_bits =
 896                 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
 897         sbi->s_desc_per_block_bits =
 898                 ilog2 (EXT2_DESC_PER_BLOCK(sb));
 899
 900         if (sb->s_magic != EXT2_SUPER_MAGIC)
 901                 goto cantfind_ext2;
 902
 903         if (sb->s_blocksize != bh->b_size) {
 904                 if (!silent)
 905                         printk ("VFS: Unsupported blocksize on dev "
 906                                 "%s.\n", sb->s_id);
 907                 goto failed_mount;
 908         }
 909
 910         if (sb->s_blocksize != sbi->s_frag_size) {
 911                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
 912                         sbi->s_frag_size, sb->s_blocksize);
 913                 goto failed_mount;
 914         }
 915
 916         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
 917                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
 918                         sbi->s_blocks_per_group);
 919                 goto failed_mount;
 920         }
 921         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 922                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
 923                         sbi->s_frags_per_group);
 924                 goto failed_mount;
 925         }
 926         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
 927                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
 928                         sbi->s_inodes_per_group);
 929                 goto failed_mount;
 930         }
 931
 932         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
 933                 goto cantfind_ext2;
 934         sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
 935                                 le32_to_cpu(es->s_first_data_block) - 1)
 936                                         / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
 937         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
 938                    EXT2_DESC_PER_BLOCK(sb);
 939         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
 940         if (sbi->s_group_desc == NULL) {
 941                 printk ("EXT2-fs: not enough memory\n");
 942                 goto failed_mount;
 943         }
 944         bgl_lock_init(&sbi->s_blockgroup_lock);
 945         sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
 946         if (!sbi->s_debts) {
 947                 printk ("EXT2-fs: not enough memory\n");
 948                 goto failed_mount_group_desc;
 949         }
 950         for (i = 0; i < db_count; i++) {
 951                 block = descriptor_loc(sb, logic_sb_block, i);
 952                 sbi->s_group_desc[i] = sb_bread(sb, block);
 953                 if (!sbi->s_group_desc[i]) {
 954                         for (j = 0; j < i; j++)
 955                                 brelse (sbi->s_group_desc[j]);
 956                         printk ("EXT2-fs: unable to read group descriptors\n");
 957                         goto failed_mount_group_desc;
 958                 }
 959         }
 960         if (!ext2_check_descriptors (sb)) {
 961                 printk ("EXT2-fs: group descriptors corrupted!\n");
 962                 goto failed_mount2;
 963         }
 964         sbi->s_gdb_count = db_count;
 965         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
 966         spin_lock_init(&sbi->s_next_gen_lock);
 967
 968         err = percpu_counter_init(&sbi->s_freeblocks_counter,
 969                                 ext2_count_free_blocks(sb));
 970         if (!err) {
 971                 err = percpu_counter_init(&sbi->s_freeinodes_counter,
 972                                 ext2_count_free_inodes(sb));
 973         }
 974         if (!err) {
 975                 err = percpu_counter_init(&sbi->s_dirs_counter,
 976                                 ext2_count_dirs(sb));
 977         }
 978         if (err) {
 979                 printk(KERN_ERR "EXT2-fs: insufficient memory\n");
 980                 goto failed_mount3;
 981         }
 982         /*
 983          * set up enough so that it can read an inode
 984          */
 985         sb->s_op = &ext2_sops;
 986         sb->s_export_op = &ext2_export_ops;
 987         sb->s_xattr = ext2_xattr_handlers;
 988         root = iget(sb, EXT2_ROOT_INO);
 989         sb->s_root = d_alloc_root(root);
 990         if (!sb->s_root) {
 991                 iput(root);
 992                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
 993                 goto failed_mount3;
 994         }
 995         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
 996                 dput(sb->s_root);
 997                 sb->s_root = NULL;
 998                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
 999                 goto failed_mount3;
1000         }
1001         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1002                 ext2_warning(sb, __FUNCTION__,
1003                         "mounting ext3 filesystem as ext2");
1004         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
1005         return 0;
1006
1007 cantfind_ext2:
1008         if (!silent)
1009                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
1010                        sb->s_id);
1011         goto failed_mount;
1012 failed_mount3:
1013         percpu_counter_destroy(&sbi->s_freeblocks_counter);
1014         percpu_counter_destroy(&sbi->s_freeinodes_counter);
1015         percpu_counter_destroy(&sbi->s_dirs_counter);
1016 failed_mount2:
1017         for (i = 0; i < db_count; i++)
1018                 brelse(sbi->s_group_desc[i]);
1019 failed_mount_group_desc:
1020         kfree(sbi->s_group_desc);
1021         kfree(sbi->s_debts);
1022 failed_mount:
1023         brelse(bh);
1024 failed_sbi:
1025         sb->s_fs_info = NULL;
1026         kfree(sbi);
1027         return -EINVAL;
1028 }
1029
1030 static void ext2_commit_super (struct super_block * sb,
1031                                struct ext2_super_block * es)
1032 {
1033         es->s_wtime = cpu_to_le32(get_seconds());
1034         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1035         sb->s_dirt = 0;
1036 }
1037
1038 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
1039 {
1040         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1041         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1042         es->s_wtime = cpu_to_le32(get_seconds());
1043         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1044         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1045         sb->s_dirt = 0;
1046 }
1047
1048 /*
1049  * In the second extended file system, it is not necessary to
1050  * write the super block since we use a mapping of the
1051  * disk super block in a buffer.
1052  *
1053  * However, this function is still used to set the fs valid
1054  * flags to 0.  We need to set this flag to 0 since the fs
1055  * may have been checked while mounted and e2fsck may have
1056  * set s_state to EXT2_VALID_FS after some corrections.
1057  */
1058
1059 void ext2_write_super (struct super_block * sb)
1060 {
1061         struct ext2_super_block * es;
1062         lock_kernel();
1063         if (!(sb->s_flags & MS_RDONLY)) {
1064                 es = EXT2_SB(sb)->s_es;
1065
1066                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
1067                         ext2_debug ("setting valid to 0\n");
1068                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
1069                                                   ~EXT2_VALID_FS);
1070                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1071                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1072                         es->s_mtime = cpu_to_le32(get_seconds());
1073                         ext2_sync_super(sb, es);
1074                 } else
1075                         ext2_commit_super (sb, es);
1076         }
1077         sb->s_dirt = 0;
1078         unlock_kernel();
1079 }
1080
1081 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1082 {
1083         struct ext2_sb_info * sbi = EXT2_SB(sb);
1084         struct ext2_super_block * es;
1085         unsigned long old_mount_opt = sbi->s_mount_opt;
1086         struct ext2_mount_options old_opts;
1087         unsigned long old_sb_flags;
1088         int err;
1089
1090         /* Store the old options */
1091         old_sb_flags = sb->s_flags;
1092         old_opts.s_mount_opt = sbi->s_mount_opt;
1093         old_opts.s_resuid = sbi->s_resuid;
1094         old_opts.s_resgid = sbi->s_resgid;
1095
1096         /*
1097          * Allow the "check" option to be passed as a remount option.
1098          */
1099         if (!parse_options (data, sbi)) {
1100                 err = -EINVAL;
1101                 goto restore_opts;
1102         }
1103
1104         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1105                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1106
1107         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
1108                                     EXT2_MOUNT_XIP if not */
1109
1110         if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
1111                 printk("XIP: Unsupported blocksize\n");
1112                 err = -EINVAL;
1113                 goto restore_opts;
1114         }
1115
1116         es = sbi->s_es;
1117         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
1118             (old_mount_opt & EXT2_MOUNT_XIP)) &&
1119             invalidate_inodes(sb))
1120                 ext2_warning(sb, __FUNCTION__, "busy inodes while remounting "\
1121                              "xip remain in cache (no functional problem)");
1122         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1123                 return 0;
1124         if (*flags & MS_RDONLY) {
1125                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1126                     !(sbi->s_mount_state & EXT2_VALID_FS))
1127                         return 0;
1128                 /*
1129                  * OK, we are remounting a valid rw partition rdonly, so set
1130                  * the rdonly flag and then mark the partition as valid again.
1131                  */
1132                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1133                 es->s_mtime = cpu_to_le32(get_seconds());
1134         } else {
1135                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1136                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1137                 if (ret) {
1138                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
1139                                "unsupported optional features (%x).\n",
1140                                sb->s_id, le32_to_cpu(ret));
1141                         err = -EROFS;
1142                         goto restore_opts;
1143                 }
1144                 /*
1145                  * Mounting a RDONLY partition read-write, so reread and
1146                  * store the current valid flag.  (It may have been changed
1147                  * by e2fsck since we originally mounted the partition.)
1148                  */
1149                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1150                 if (!ext2_setup_super (sb, es, 0))
1151                         sb->s_flags &= ~MS_RDONLY;
1152         }
1153         ext2_sync_super(sb, es);
1154         return 0;
1155 restore_opts:
1156         sbi->s_mount_opt = old_opts.s_mount_opt;
1157         sbi->s_resuid = old_opts.s_resuid;
1158         sbi->s_resgid = old_opts.s_resgid;
1159         sb->s_flags = old_sb_flags;
1160         return err;
1161 }
1162
1163 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1164 {
1165         struct super_block *sb = dentry->d_sb;
1166         struct ext2_sb_info *sbi = EXT2_SB(sb);
1167         struct ext2_super_block *es = sbi->s_es;
1168         u64 fsid;
1169
1170         if (test_opt (sb, MINIX_DF))
1171                 sbi->s_overhead_last = 0;
1172         else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1173                 unsigned long i, overhead = 0;
1174                 smp_rmb();
1175
1176                 /*
1177                  * Compute the overhead (FS structures). This is constant
1178                  * for a given filesystem unless the number of block groups
1179                  * changes so we cache the previous value until it does.
1180                  */
1181
1182                 /*
1183                  * All of the blocks before first_data_block are
1184                  * overhead
1185                  */
1186                 overhead = le32_to_cpu(es->s_first_data_block);
1187
1188                 /*
1189                  * Add the overhead attributed to the superblock and
1190                  * block group descriptors.  If the sparse superblocks
1191                  * feature is turned on, then not all groups have this.
1192                  */
1193                 for (i = 0; i < sbi->s_groups_count; i++)
1194                         overhead += ext2_bg_has_super(sb, i) +
1195                                 ext2_bg_num_gdb(sb, i);
1196
1197                 /*
1198                  * Every block group has an inode bitmap, a block
1199                  * bitmap, and an inode table.
1200                  */
1201                 overhead += (sbi->s_groups_count *
1202                              (2 + sbi->s_itb_per_group));
1203                 sbi->s_overhead_last = overhead;
1204                 smp_wmb();
1205                 sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1206         }
1207
1208         buf->f_type = EXT2_SUPER_MAGIC;
1209         buf->f_bsize = sb->s_blocksize;
1210         buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1211         buf->f_bfree = ext2_count_free_blocks(sb);
1212         es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1213         buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1214         if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1215                 buf->f_bavail = 0;
1216         buf->f_files = le32_to_cpu(es->s_inodes_count);
1217         buf->f_ffree = ext2_count_free_inodes(sb);
1218         es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1219         buf->f_namelen = EXT2_NAME_LEN;
1220         fsid = le64_to_cpup((void *)es->s_uuid) ^
1221                le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1222         buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1223         buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1224         return 0;
1225 }
1226
1227 static int ext2_get_sb(struct file_system_type *fs_type,
1228         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1229 {
1230         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super, mnt);
1231 }
1232
1233 #ifdef CONFIG_QUOTA
1234
1235 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1236  * acquiring the locks... As quota files are never truncated and quota code
1237  * itself serializes the operations (and noone else should touch the files)
1238  * we don't have to be afraid of races */
1239 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1240                                size_t len, loff_t off)
1241 {
1242         struct inode *inode = sb_dqopt(sb)->files[type];
1243         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1244         int err = 0;
1245         int offset = off & (sb->s_blocksize - 1);
1246         int tocopy;
1247         size_t toread;
1248         struct buffer_head tmp_bh;
1249         struct buffer_head *bh;
1250         loff_t i_size = i_size_read(inode);
1251
1252         if (off > i_size)
1253                 return 0;
1254         if (off+len > i_size)
1255                 len = i_size-off;
1256         toread = len;
1257         while (toread > 0) {
1258                 tocopy = sb->s_blocksize - offset < toread ?
1259                                 sb->s_blocksize - offset : toread;
1260
1261                 tmp_bh.b_state = 0;
1262                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1263                 if (err)
1264                         return err;
1265                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1266                         memset(data, 0, tocopy);
1267                 else {
1268                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1269                         if (!bh)
1270                                 return -EIO;
1271                         memcpy(data, bh->b_data+offset, tocopy);
1272                         brelse(bh);
1273                 }
1274                 offset = 0;
1275                 toread -= tocopy;
1276                 data += tocopy;
1277                 blk++;
1278         }
1279         return len;
1280 }
1281
1282 /* Write to quotafile */
1283 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1284                                 const char *data, size_t len, loff_t off)
1285 {
1286         struct inode *inode = sb_dqopt(sb)->files[type];
1287         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1288         int err = 0;
1289         int offset = off & (sb->s_blocksize - 1);
1290         int tocopy;
1291         size_t towrite = len;
1292         struct buffer_head tmp_bh;
1293         struct buffer_head *bh;
1294
1295         mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1296         while (towrite > 0) {
1297                 tocopy = sb->s_blocksize - offset < towrite ?
1298                                 sb->s_blocksize - offset : towrite;
1299
1300                 tmp_bh.b_state = 0;
1301                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1302                 if (err)
1303                         goto out;
1304                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1305                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1306                 else
1307                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1308                 if (!bh) {
1309                         err = -EIO;
1310                         goto out;
1311                 }
1312                 lock_buffer(bh);
1313                 memcpy(bh->b_data+offset, data, tocopy);
1314                 flush_dcache_page(bh->b_page);
1315                 set_buffer_uptodate(bh);
1316                 mark_buffer_dirty(bh);
1317                 unlock_buffer(bh);
1318                 brelse(bh);
1319                 offset = 0;
1320                 towrite -= tocopy;
1321                 data += tocopy;
1322                 blk++;
1323         }
1324 out:
1325         if (len == towrite)
1326                 return err;
1327         if (inode->i_size < off+len-towrite)
1328                 i_size_write(inode, off+len-towrite);
1329         inode->i_version++;
1330         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1331         mark_inode_dirty(inode);
1332         mutex_unlock(&inode->i_mutex);
1333         return len - towrite;
1334 }
1335
1336 #endif
1337
1338 static struct file_system_type ext2_fs_type = {
1339         .owner          = THIS_MODULE,
1340         .name           = "ext2",
1341         .get_sb         = ext2_get_sb,
1342         .kill_sb        = kill_block_super,
1343         .fs_flags       = FS_REQUIRES_DEV,
1344 };
1345
1346 static int __init init_ext2_fs(void)
1347 {
1348         int err = init_ext2_xattr();
1349         if (err)
1350                 return err;
1351         err = init_inodecache();
1352         if (err)
1353                 goto out1;
1354         err = register_filesystem(&ext2_fs_type);
1355         if (err)
1356                 goto out;
1357         return 0;
1358 out:
1359         destroy_inodecache();
1360 out1:
1361         exit_ext2_xattr();
1362         return err;
1363 }
1364
1365 static void __exit exit_ext2_fs(void)
1366 {
1367         unregister_filesystem(&ext2_fs_type);
1368         destroy_inodecache();
1369         exit_ext2_xattr();
1370 }
1371
1372 module_init(init_ext2_fs)
1373 module_exit(exit_ext2_fs)