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->i_block_alloc_info = NULL;
 153         ei->vfs_inode.i_version = 1;
 154         return &ei->vfs_inode;
 155 }
 156
 157 static void ext2_destroy_inode(struct inode *inode)
 158 {
 159         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
 160 }
 161
 162 static void init_once(struct kmem_cache * cachep, void *foo)
 163 {
 164         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
 165
 166         rwlock_init(&ei->i_meta_lock);
 167 #ifdef CONFIG_EXT2_FS_XATTR
 168         init_rwsem(&ei->xattr_sem);
 169 #endif
 170         mutex_init(&ei->truncate_mutex);
 171         inode_init_once(&ei->vfs_inode);
 172 }
 173
 174 static int init_inodecache(void)
 175 {
 176         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
 177                                              sizeof(struct ext2_inode_info),
 178                                              0, (SLAB_RECLAIM_ACCOUNT|
 179                                                 SLAB_MEM_SPREAD),
 180                                              init_once);
 181         if (ext2_inode_cachep == NULL)
 182                 return -ENOMEM;
 183         return 0;
 184 }
 185
 186 static void destroy_inodecache(void)
 187 {
 188         kmem_cache_destroy(ext2_inode_cachep);
 189 }
 190
 191 static void ext2_clear_inode(struct inode *inode)
 192 {
 193         struct ext2_block_alloc_info *rsv = EXT2_I(inode)->i_block_alloc_info;
 194 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 195         struct ext2_inode_info *ei = EXT2_I(inode);
 196
 197         if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
 198                 posix_acl_release(ei->i_acl);
 199                 ei->i_acl = EXT2_ACL_NOT_CACHED;
 200         }
 201         if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
 202                 posix_acl_release(ei->i_default_acl);
 203                 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 204         }
 205 #endif
 206         ext2_discard_reservation(inode);
 207         EXT2_I(inode)->i_block_alloc_info = NULL;
 208         if (unlikely(rsv))
 209                 kfree(rsv);
 210 }
 211
 212 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
 213 {
 214         struct super_block *sb = vfs->mnt_sb;
 215         struct ext2_sb_info *sbi = EXT2_SB(sb);
 216         struct ext2_super_block *es = sbi->s_es;
 217         unsigned long def_mount_opts;
 218
 219         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 220
 221         if (sbi->s_sb_block != 1)
 222                 seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
 223         if (test_opt(sb, MINIX_DF))
 224                 seq_puts(seq, ",minixdf");
 225         if (test_opt(sb, GRPID))
 226                 seq_puts(seq, ",grpid");
 227         if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
 228                 seq_puts(seq, ",nogrpid");
 229         if (sbi->s_resuid != EXT2_DEF_RESUID ||
 230             le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
 231                 seq_printf(seq, ",resuid=%u", sbi->s_resuid);
 232         }
 233         if (sbi->s_resgid != EXT2_DEF_RESGID ||
 234             le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
 235                 seq_printf(seq, ",resgid=%u", sbi->s_resgid);
 236         }
 237         if (test_opt(sb, ERRORS_RO)) {
 238                 int def_errors = le16_to_cpu(es->s_errors);
 239
 240                 if (def_errors == EXT2_ERRORS_PANIC ||
 241                     def_errors == EXT2_ERRORS_CONTINUE) {
 242                         seq_puts(seq, ",errors=remount-ro");
 243                 }
 244         }
 245         if (test_opt(sb, ERRORS_CONT))
 246                 seq_puts(seq, ",errors=continue");
 247         if (test_opt(sb, ERRORS_PANIC))
 248                 seq_puts(seq, ",errors=panic");
 249         if (test_opt(sb, NO_UID32))
 250                 seq_puts(seq, ",nouid32");
 251         if (test_opt(sb, DEBUG))
 252                 seq_puts(seq, ",debug");
 253         if (test_opt(sb, OLDALLOC))
 254                 seq_puts(seq, ",oldalloc");
 255
 256 #ifdef CONFIG_EXT2_FS_XATTR
 257         if (test_opt(sb, XATTR_USER))
 258                 seq_puts(seq, ",user_xattr");
 259         if (!test_opt(sb, XATTR_USER) &&
 260             (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
 261                 seq_puts(seq, ",nouser_xattr");
 262         }
 263 #endif
 264
 265 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 266         if (test_opt(sb, POSIX_ACL))
 267                 seq_puts(seq, ",acl");
 268         if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
 269                 seq_puts(seq, ",noacl");
 270 #endif
 271
 272         if (test_opt(sb, NOBH))
 273                 seq_puts(seq, ",nobh");
 274
 275 #if defined(CONFIG_QUOTA)
 276         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
 277                 seq_puts(seq, ",usrquota");
 278
 279         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
 280                 seq_puts(seq, ",grpquota");
 281 #endif
 282
 283 #if defined(CONFIG_EXT2_FS_XIP)
 284         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
 285                 seq_puts(seq, ",xip");
 286 #endif
 287
 288         return 0;
 289 }
 290
 291 #ifdef CONFIG_QUOTA
 292 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
 293 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
 294 #endif
 295
 296 static const struct super_operations ext2_sops = {
 297         .alloc_inode    = ext2_alloc_inode,
 298         .destroy_inode  = ext2_destroy_inode,
 299         .write_inode    = ext2_write_inode,
 300         .delete_inode   = ext2_delete_inode,
 301         .put_super      = ext2_put_super,
 302         .write_super    = ext2_write_super,
 303         .statfs         = ext2_statfs,
 304         .remount_fs     = ext2_remount,
 305         .clear_inode    = ext2_clear_inode,
 306         .show_options   = ext2_show_options,
 307 #ifdef CONFIG_QUOTA
 308         .quota_read     = ext2_quota_read,
 309         .quota_write    = ext2_quota_write,
 310 #endif
 311 };
 312
 313 static struct inode *ext2_nfs_get_inode(struct super_block *sb,
 314                 u64 ino, u32 generation)
 315 {
 316         struct inode *inode;
 317
 318         if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
 319                 return ERR_PTR(-ESTALE);
 320         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
 321                 return ERR_PTR(-ESTALE);
 322
 323         /* iget isn't really right if the inode is currently unallocated!!
 324          * ext2_read_inode currently does appropriate checks, but
 325          * it might be "neater" to call ext2_get_inode first and check
 326          * if the inode is valid.....
 327          */
 328         inode = ext2_iget(sb, ino);
 329         if (IS_ERR(inode))
 330                 return ERR_CAST(inode);
 331         if (generation && inode->i_generation != generation) {
 332                 /* we didn't find the right inode.. */
 333                 iput(inode);
 334                 return ERR_PTR(-ESTALE);
 335         }
 336         return inode;
 337 }
 338
 339 static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 340                 int fh_len, int fh_type)
 341 {
 342         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 343                                     ext2_nfs_get_inode);
 344 }
 345
 346 static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
 347                 int fh_len, int fh_type)
 348 {
 349         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 350                                     ext2_nfs_get_inode);
 351 }
 352
 353 /* Yes, most of these are left as NULL!!
 354  * A NULL value implies the default, which works with ext2-like file
 355  * systems, but can be improved upon.
 356  * Currently only get_parent is required.
 357  */
 358 static const struct export_operations ext2_export_ops = {
 359         .fh_to_dentry = ext2_fh_to_dentry,
 360         .fh_to_parent = ext2_fh_to_parent,
 361         .get_parent = ext2_get_parent,
 362 };
 363
 364 static unsigned long get_sb_block(void **data)
 365 {
 366         unsigned long   sb_block;
 367         char            *options = (char *) *data;
 368
 369         if (!options || strncmp(options, "sb=", 3) != 0)
 370                 return 1;       /* Default location */
 371         options += 3;
 372         sb_block = simple_strtoul(options, &options, 0);
 373         if (*options && *options != ',') {
 374                 printk("EXT2-fs: Invalid sb specification: %s\n",
 375                        (char *) *data);
 376                 return 1;
 377         }
 378         if (*options == ',')
 379                 options++;
 380         *data = (void *) options;
 381         return sb_block;
 382 }
 383
 384 enum {
 385         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
 386         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
 387         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
 388         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
 389         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
 390         Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
 391 };
 392
 393 static match_table_t tokens = {
 394         {Opt_bsd_df, "bsddf"},
 395         {Opt_minix_df, "minixdf"},
 396         {Opt_grpid, "grpid"},
 397         {Opt_grpid, "bsdgroups"},
 398         {Opt_nogrpid, "nogrpid"},
 399         {Opt_nogrpid, "sysvgroups"},
 400         {Opt_resgid, "resgid=%u"},
 401         {Opt_resuid, "resuid=%u"},
 402         {Opt_sb, "sb=%u"},
 403         {Opt_err_cont, "errors=continue"},
 404         {Opt_err_panic, "errors=panic"},
 405         {Opt_err_ro, "errors=remount-ro"},
 406         {Opt_nouid32, "nouid32"},
 407         {Opt_nocheck, "check=none"},
 408         {Opt_nocheck, "nocheck"},
 409         {Opt_debug, "debug"},
 410         {Opt_oldalloc, "oldalloc"},
 411         {Opt_orlov, "orlov"},
 412         {Opt_nobh, "nobh"},
 413         {Opt_user_xattr, "user_xattr"},
 414         {Opt_nouser_xattr, "nouser_xattr"},
 415         {Opt_acl, "acl"},
 416         {Opt_noacl, "noacl"},
 417         {Opt_xip, "xip"},
 418         {Opt_grpquota, "grpquota"},
 419         {Opt_ignore, "noquota"},
 420         {Opt_quota, "quota"},
 421         {Opt_usrquota, "usrquota"},
 422         {Opt_reservation, "reservation"},
 423         {Opt_noreservation, "noreservation"},
 424         {Opt_err, NULL}
 425 };
 426
 427 static int parse_options (char * options,
 428                           struct ext2_sb_info *sbi)
 429 {
 430         char * p;
 431         substring_t args[MAX_OPT_ARGS];
 432         int option;
 433
 434         if (!options)
 435                 return 1;
 436
 437         while ((p = strsep (&options, ",")) != NULL) {
 438                 int token;
 439                 if (!*p)
 440                         continue;
 441
 442                 token = match_token(p, tokens, args);
 443                 switch (token) {
 444                 case Opt_bsd_df:
 445                         clear_opt (sbi->s_mount_opt, MINIX_DF);
 446                         break;
 447                 case Opt_minix_df:
 448                         set_opt (sbi->s_mount_opt, MINIX_DF);
 449                         break;
 450                 case Opt_grpid:
 451                         set_opt (sbi->s_mount_opt, GRPID);
 452                         break;
 453                 case Opt_nogrpid:
 454                         clear_opt (sbi->s_mount_opt, GRPID);
 455                         break;
 456                 case Opt_resuid:
 457                         if (match_int(&args[0], &option))
 458                                 return 0;
 459                         sbi->s_resuid = option;
 460                         break;
 461                 case Opt_resgid:
 462                         if (match_int(&args[0], &option))
 463                                 return 0;
 464                         sbi->s_resgid = option;
 465                         break;
 466                 case Opt_sb:
 467                         /* handled by get_sb_block() instead of here */
 468                         /* *sb_block = match_int(&args[0]); */
 469                         break;
 470                 case Opt_err_panic:
 471                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 472                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
 473                         set_opt (sbi->s_mount_opt, ERRORS_PANIC);
 474                         break;
 475                 case Opt_err_ro:
 476                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 477                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 478                         set_opt (sbi->s_mount_opt, ERRORS_RO);
 479                         break;
 480                 case Opt_err_cont:
 481                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
 482                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 483                         set_opt (sbi->s_mount_opt, ERRORS_CONT);
 484                         break;
 485                 case Opt_nouid32:
 486                         set_opt (sbi->s_mount_opt, NO_UID32);
 487                         break;
 488                 case Opt_nocheck:
 489                         clear_opt (sbi->s_mount_opt, CHECK);
 490                         break;
 491                 case Opt_debug:
 492                         set_opt (sbi->s_mount_opt, DEBUG);
 493                         break;
 494                 case Opt_oldalloc:
 495                         set_opt (sbi->s_mount_opt, OLDALLOC);
 496                         break;
 497                 case Opt_orlov:
 498                         clear_opt (sbi->s_mount_opt, OLDALLOC);
 499                         break;
 500                 case Opt_nobh:
 501                         set_opt (sbi->s_mount_opt, NOBH);
 502                         break;
 503 #ifdef CONFIG_EXT2_FS_XATTR
 504                 case Opt_user_xattr:
 505                         set_opt (sbi->s_mount_opt, XATTR_USER);
 506                         break;
 507                 case Opt_nouser_xattr:
 508                         clear_opt (sbi->s_mount_opt, XATTR_USER);
 509                         break;
 510 #else
 511                 case Opt_user_xattr:
 512                 case Opt_nouser_xattr:
 513                         printk("EXT2 (no)user_xattr options not supported\n");
 514                         break;
 515 #endif
 516 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 517                 case Opt_acl:
 518                         set_opt(sbi->s_mount_opt, POSIX_ACL);
 519                         break;
 520                 case Opt_noacl:
 521                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
 522                         break;
 523 #else
 524                 case Opt_acl:
 525                 case Opt_noacl:
 526                         printk("EXT2 (no)acl options not supported\n");
 527                         break;
 528 #endif
 529                 case Opt_xip:
 530 #ifdef CONFIG_EXT2_FS_XIP
 531                         set_opt (sbi->s_mount_opt, XIP);
 532 #else
 533                         printk("EXT2 xip option not supported\n");
 534 #endif
 535                         break;
 536
 537 #if defined(CONFIG_QUOTA)
 538                 case Opt_quota:
 539                 case Opt_usrquota:
 540                         set_opt(sbi->s_mount_opt, USRQUOTA);
 541                         break;
 542
 543                 case Opt_grpquota:
 544                         set_opt(sbi->s_mount_opt, GRPQUOTA);
 545                         break;
 546 #else
 547                 case Opt_quota:
 548                 case Opt_usrquota:
 549                 case Opt_grpquota:
 550                         printk(KERN_ERR
 551                                 "EXT2-fs: quota operations not supported.\n");
 552
 553                         break;
 554 #endif
 555
 556                 case Opt_reservation:
 557                         set_opt(sbi->s_mount_opt, RESERVATION);
 558                         printk("reservations ON\n");
 559                         break;
 560                 case Opt_noreservation:
 561                         clear_opt(sbi->s_mount_opt, RESERVATION);
 562                         printk("reservations OFF\n");
 563                         break;
 564                 case Opt_ignore:
 565                         break;
 566                 default:
 567                         return 0;
 568                 }
 569         }
 570         return 1;
 571 }
 572
 573 static int ext2_setup_super (struct super_block * sb,
 574                               struct ext2_super_block * es,
 575                               int read_only)
 576 {
 577         int res = 0;
 578         struct ext2_sb_info *sbi = EXT2_SB(sb);
 579
 580         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 581                 printk ("EXT2-fs warning: revision level too high, "
 582                         "forcing read-only mode\n");
 583                 res = MS_RDONLY;
 584         }
 585         if (read_only)
 586                 return res;
 587         if (!(sbi->s_mount_state & EXT2_VALID_FS))
 588                 printk ("EXT2-fs warning: mounting unchecked fs, "
 589                         "running e2fsck is recommended\n");
 590         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 591                 printk ("EXT2-fs warning: mounting fs with errors, "
 592                         "running e2fsck is recommended\n");
 593         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 594                  le16_to_cpu(es->s_mnt_count) >=
 595                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 596                 printk ("EXT2-fs warning: maximal mount count reached, "
 597                         "running e2fsck is recommended\n");
 598         else if (le32_to_cpu(es->s_checkinterval) &&
 599                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 600                 printk ("EXT2-fs warning: checktime reached, "
 601                         "running e2fsck is recommended\n");
 602         if (!le16_to_cpu(es->s_max_mnt_count))
 603                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 604         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
 605         ext2_write_super(sb);
 606         if (test_opt (sb, DEBUG))
 607                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
 608                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
 609                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 610                         sbi->s_frag_size,
 611                         sbi->s_groups_count,
 612                         EXT2_BLOCKS_PER_GROUP(sb),
 613                         EXT2_INODES_PER_GROUP(sb),
 614                         sbi->s_mount_opt);
 615         return res;
 616 }
 617
 618 static int ext2_check_descriptors(struct super_block *sb)
 619 {
 620         int i;
 621         struct ext2_sb_info *sbi = EXT2_SB(sb);
 622         unsigned long first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 623         unsigned long last_block;
 624
 625         ext2_debug ("Checking group descriptors");
 626
 627         for (i = 0; i < sbi->s_groups_count; i++) {
 628                 struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
 629
 630                 if (i == sbi->s_groups_count - 1)
 631                         last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
 632                 else
 633                         last_block = first_block +
 634                                 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
 635
 636                 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
 637                     le32_to_cpu(gdp->bg_block_bitmap) > last_block)
 638                 {
 639                         ext2_error (sb, "ext2_check_descriptors",
 640                                     "Block bitmap for group %d"
 641                                     " not in group (block %lu)!",
 642                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 643                         return 0;
 644                 }
 645                 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
 646                     le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
 647                 {
 648                         ext2_error (sb, "ext2_check_descriptors",
 649                                     "Inode bitmap for group %d"
 650                                     " not in group (block %lu)!",
 651                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 652                         return 0;
 653                 }
 654                 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
 655                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
 656                     last_block)
 657                 {
 658                         ext2_error (sb, "ext2_check_descriptors",
 659                                     "Inode table for group %d"
 660                                     " not in group (block %lu)!",
 661                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 662                         return 0;
 663                 }
 664                 first_block += EXT2_BLOCKS_PER_GROUP(sb);
 665         }
 666         return 1;
 667 }
 668
 669 /*
 670  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 671  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 672  * We need to be 1 filesystem block less than the 2^32 sector limit.
 673  */
 674 static loff_t ext2_max_size(int bits)
 675 {
 676         loff_t res = EXT2_NDIR_BLOCKS;
 677         int meta_blocks;
 678         loff_t upper_limit;
 679
 680         /* This is calculated to be the largest file size for a
 681          * dense, file such that the total number of
 682          * sectors in the file, including data and all indirect blocks,
 683          * does not exceed 2^32 -1
 684          * __u32 i_blocks representing the total number of
 685          * 512 bytes blocks of the file
 686          */
 687         upper_limit = (1LL << 32) - 1;
 688
 689         /* total blocks in file system block size */
 690         upper_limit >>= (bits - 9);
 691
 692
 693         /* indirect blocks */
 694         meta_blocks = 1;
 695         /* double indirect blocks */
 696         meta_blocks += 1 + (1LL << (bits-2));
 697         /* tripple indirect blocks */
 698         meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
 699
 700         upper_limit -= meta_blocks;
 701         upper_limit <<= bits;
 702
 703         res += 1LL << (bits-2);
 704         res += 1LL << (2*(bits-2));
 705         res += 1LL << (3*(bits-2));
 706         res <<= bits;
 707         if (res > upper_limit)
 708                 res = upper_limit;
 709
 710         if (res > MAX_LFS_FILESIZE)
 711                 res = MAX_LFS_FILESIZE;
 712
 713         return res;
 714 }
 715
 716 static unsigned long descriptor_loc(struct super_block *sb,
 717                                     unsigned long logic_sb_block,
 718                                     int nr)
 719 {
 720         struct ext2_sb_info *sbi = EXT2_SB(sb);
 721         unsigned long bg, first_data_block, first_meta_bg;
 722         int has_super = 0;
 723
 724         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 725         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 726
 727         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 728             nr < first_meta_bg)
 729                 return (logic_sb_block + nr + 1);
 730         bg = sbi->s_desc_per_block * nr;
 731         if (ext2_bg_has_super(sb, bg))
 732                 has_super = 1;
 733         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
 734 }
 735
 736 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 737 {
 738         struct buffer_head * bh;
 739         struct ext2_sb_info * sbi;
 740         struct ext2_super_block * es;
 741         struct inode *root;
 742         unsigned long block;
 743         unsigned long sb_block = get_sb_block(&data);
 744         unsigned long logic_sb_block;
 745         unsigned long offset = 0;
 746         unsigned long def_mount_opts;
 747         long ret = -EINVAL;
 748         int blocksize = BLOCK_SIZE;
 749         int db_count;
 750         int i, j;
 751         __le32 features;
 752         int err;
 753
 754         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 755         if (!sbi)
 756                 return -ENOMEM;
 757         sb->s_fs_info = sbi;
 758         sbi->s_sb_block = sb_block;
 759
 760         /*
 761          * See what the current blocksize for the device is, and
 762          * use that as the blocksize.  Otherwise (or if the blocksize
 763          * is smaller than the default) use the default.
 764          * This is important for devices that have a hardware
 765          * sectorsize that is larger than the default.
 766          */
 767         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 768         if (!blocksize) {
 769                 printk ("EXT2-fs: unable to set blocksize\n");
 770                 goto failed_sbi;
 771         }
 772
 773         /*
 774          * If the superblock doesn't start on a hardware sector boundary,
 775          * calculate the offset.
 776          */
 777         if (blocksize != BLOCK_SIZE) {
 778                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 779                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 780         } else {
 781                 logic_sb_block = sb_block;
 782         }
 783
 784         if (!(bh = sb_bread(sb, logic_sb_block))) {
 785                 printk ("EXT2-fs: unable to read superblock\n");
 786                 goto failed_sbi;
 787         }
 788         /*
 789          * Note: s_es must be initialized as soon as possible because
 790          *       some ext2 macro-instructions depend on its value
 791          */
 792         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 793         sbi->s_es = es;
 794         sb->s_magic = le16_to_cpu(es->s_magic);
 795
 796         if (sb->s_magic != EXT2_SUPER_MAGIC)
 797                 goto cantfind_ext2;
 798
 799         /* Set defaults before we parse the mount options */
 800         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 801         if (def_mount_opts & EXT2_DEFM_DEBUG)
 802                 set_opt(sbi->s_mount_opt, DEBUG);
 803         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 804                 set_opt(sbi->s_mount_opt, GRPID);
 805         if (def_mount_opts & EXT2_DEFM_UID16)
 806                 set_opt(sbi->s_mount_opt, NO_UID32);
 807 #ifdef CONFIG_EXT2_FS_XATTR
 808         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 809                 set_opt(sbi->s_mount_opt, XATTR_USER);
 810 #endif
 811 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 812         if (def_mount_opts & EXT2_DEFM_ACL)
 813                 set_opt(sbi->s_mount_opt, POSIX_ACL);
 814 #endif
 815
 816         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 817                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 818         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
 819                 set_opt(sbi->s_mount_opt, ERRORS_CONT);
 820         else
 821                 set_opt(sbi->s_mount_opt, ERRORS_RO);
 822
 823         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
 824         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
 825
 826         set_opt(sbi->s_mount_opt, RESERVATION);
 827
 828         if (!parse_options ((char *) data, sbi))
 829                 goto failed_mount;
 830
 831         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 832                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 833                  MS_POSIXACL : 0);
 834
 835         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
 836                                     EXT2_MOUNT_XIP if not */
 837
 838         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 839             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 840              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 841              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 842                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
 843                        "running e2fsck is recommended\n");
 844         /*
 845          * Check feature flags regardless of the revision level, since we
 846          * previously didn't change the revision level when setting the flags,
 847          * so there is a chance incompat flags are set on a rev 0 filesystem.
 848          */
 849         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 850         if (features) {
 851                 printk("EXT2-fs: %s: couldn't mount because of "
 852                        "unsupported optional features (%x).\n",
 853                        sb->s_id, le32_to_cpu(features));
 854                 goto failed_mount;
 855         }
 856         if (!(sb->s_flags & MS_RDONLY) &&
 857             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 858                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
 859                        "unsupported optional features (%x).\n",
 860                        sb->s_id, le32_to_cpu(features));
 861                 goto failed_mount;
 862         }
 863
 864         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 865
 866         if (ext2_use_xip(sb) && blocksize != PAGE_SIZE) {
 867                 if (!silent)
 868                         printk("XIP: Unsupported blocksize\n");
 869                 goto failed_mount;
 870         }
 871
 872         /* If the blocksize doesn't match, re-read the thing.. */
 873         if (sb->s_blocksize != blocksize) {
 874                 brelse(bh);
 875
 876                 if (!sb_set_blocksize(sb, blocksize)) {
 877                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
 878                         goto failed_sbi;
 879                 }
 880
 881                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 882                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 883                 bh = sb_bread(sb, logic_sb_block);
 884                 if(!bh) {
 885                         printk("EXT2-fs: Couldn't read superblock on "
 886                                "2nd try.\n");
 887                         goto failed_sbi;
 888                 }
 889                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 890                 sbi->s_es = es;
 891                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 892                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
 893                         goto failed_mount;
 894                 }
 895         }
 896
 897         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 898
 899         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 900                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 901                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 902         } else {
 903                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 904                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 905                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 906                     !is_power_of_2(sbi->s_inode_size) ||
 907                     (sbi->s_inode_size > blocksize)) {
 908                         printk ("EXT2-fs: unsupported inode size: %d\n",
 909                                 sbi->s_inode_size);
 910                         goto failed_mount;
 911                 }
 912         }
 913
 914         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 915                                    le32_to_cpu(es->s_log_frag_size);
 916         if (sbi->s_frag_size == 0)
 917                 goto cantfind_ext2;
 918         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
 919
 920         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 921         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 922         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 923
 924         if (EXT2_INODE_SIZE(sb) == 0)
 925                 goto cantfind_ext2;
 926         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
 927         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
 928                 goto cantfind_ext2;
 929         sbi->s_itb_per_group = sbi->s_inodes_per_group /
 930                                         sbi->s_inodes_per_block;
 931         sbi->s_desc_per_block = sb->s_blocksize /
 932                                         sizeof (struct ext2_group_desc);
 933         sbi->s_sbh = bh;
 934         sbi->s_mount_state = le16_to_cpu(es->s_state);
 935         sbi->s_addr_per_block_bits =
 936                 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
 937         sbi->s_desc_per_block_bits =
 938                 ilog2 (EXT2_DESC_PER_BLOCK(sb));
 939
 940         if (sb->s_magic != EXT2_SUPER_MAGIC)
 941                 goto cantfind_ext2;
 942
 943         if (sb->s_blocksize != bh->b_size) {
 944                 if (!silent)
 945                         printk ("VFS: Unsupported blocksize on dev "
 946                                 "%s.\n", sb->s_id);
 947                 goto failed_mount;
 948         }
 949
 950         if (sb->s_blocksize != sbi->s_frag_size) {
 951                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
 952                         sbi->s_frag_size, sb->s_blocksize);
 953                 goto failed_mount;
 954         }
 955
 956         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
 957                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
 958                         sbi->s_blocks_per_group);
 959                 goto failed_mount;
 960         }
 961         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 962                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
 963                         sbi->s_frags_per_group);
 964                 goto failed_mount;
 965         }
 966         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
 967                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
 968                         sbi->s_inodes_per_group);
 969                 goto failed_mount;
 970         }
 971
 972         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
 973                 goto cantfind_ext2;
 974         sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
 975                                 le32_to_cpu(es->s_first_data_block) - 1)
 976                                         / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
 977         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
 978                    EXT2_DESC_PER_BLOCK(sb);
 979         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
 980         if (sbi->s_group_desc == NULL) {
 981                 printk ("EXT2-fs: not enough memory\n");
 982                 goto failed_mount;
 983         }
 984         bgl_lock_init(&sbi->s_blockgroup_lock);
 985         sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
 986         if (!sbi->s_debts) {
 987                 printk ("EXT2-fs: not enough memory\n");
 988                 goto failed_mount_group_desc;
 989         }
 990         for (i = 0; i < db_count; i++) {
 991                 block = descriptor_loc(sb, logic_sb_block, i);
 992                 sbi->s_group_desc[i] = sb_bread(sb, block);
 993                 if (!sbi->s_group_desc[i]) {
 994                         for (j = 0; j < i; j++)
 995                                 brelse (sbi->s_group_desc[j]);
 996                         printk ("EXT2-fs: unable to read group descriptors\n");
 997                         goto failed_mount_group_desc;
 998                 }
 999         }
1000         if (!ext2_check_descriptors (sb)) {
1001                 printk ("EXT2-fs: group descriptors corrupted!\n");
1002                 goto failed_mount2;
1003         }
1004         sbi->s_gdb_count = db_count;
1005         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1006         spin_lock_init(&sbi->s_next_gen_lock);
1007
1008         /* per fileystem reservation list head & lock */
1009         spin_lock_init(&sbi->s_rsv_window_lock);
1010         sbi->s_rsv_window_root = RB_ROOT;
1011         /*
1012          * Add a single, static dummy reservation to the start of the
1013          * reservation window list --- it gives us a placeholder for
1014          * append-at-start-of-list which makes the allocation logic
1015          * _much_ simpler.
1016          */
1017         sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1018         sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1019         sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1020         sbi->s_rsv_window_head.rsv_goal_size = 0;
1021         ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1022
1023         err = percpu_counter_init(&sbi->s_freeblocks_counter,
1024                                 ext2_count_free_blocks(sb));
1025         if (!err) {
1026                 err = percpu_counter_init(&sbi->s_freeinodes_counter,
1027                                 ext2_count_free_inodes(sb));
1028         }
1029         if (!err) {
1030                 err = percpu_counter_init(&sbi->s_dirs_counter,
1031                                 ext2_count_dirs(sb));
1032         }
1033         if (err) {
1034                 printk(KERN_ERR "EXT2-fs: insufficient memory\n");
1035                 goto failed_mount3;
1036         }
1037         /*
1038          * set up enough so that it can read an inode
1039          */
1040         sb->s_op = &ext2_sops;
1041         sb->s_export_op = &ext2_export_ops;
1042         sb->s_xattr = ext2_xattr_handlers;
1043         root = ext2_iget(sb, EXT2_ROOT_INO);
1044         if (IS_ERR(root)) {
1045                 ret = PTR_ERR(root);
1046                 goto failed_mount3;
1047         }
1048         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1049                 iput(root);
1050                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
1051                 goto failed_mount3;
1052         }
1053
1054         sb->s_root = d_alloc_root(root);
1055         if (!sb->s_root) {
1056                 iput(root);
1057                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
1058                 ret = -ENOMEM;
1059                 goto failed_mount3;
1060         }
1061         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1062                 ext2_warning(sb, __FUNCTION__,
1063                         "mounting ext3 filesystem as ext2");
1064         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
1065         return 0;
1066
1067 cantfind_ext2:
1068         if (!silent)
1069                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
1070                        sb->s_id);
1071         goto failed_mount;
1072 failed_mount3:
1073         percpu_counter_destroy(&sbi->s_freeblocks_counter);
1074         percpu_counter_destroy(&sbi->s_freeinodes_counter);
1075         percpu_counter_destroy(&sbi->s_dirs_counter);
1076 failed_mount2:
1077         for (i = 0; i < db_count; i++)
1078                 brelse(sbi->s_group_desc[i]);
1079 failed_mount_group_desc:
1080         kfree(sbi->s_group_desc);
1081         kfree(sbi->s_debts);
1082 failed_mount:
1083         brelse(bh);
1084 failed_sbi:
1085         sb->s_fs_info = NULL;
1086         kfree(sbi);
1087         return ret;
1088 }
1089
1090 static void ext2_commit_super (struct super_block * sb,
1091                                struct ext2_super_block * es)
1092 {
1093         es->s_wtime = cpu_to_le32(get_seconds());
1094         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1095         sb->s_dirt = 0;
1096 }
1097
1098 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
1099 {
1100         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1101         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1102         es->s_wtime = cpu_to_le32(get_seconds());
1103         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1104         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1105         sb->s_dirt = 0;
1106 }
1107
1108 /*
1109  * In the second extended file system, it is not necessary to
1110  * write the super block since we use a mapping of the
1111  * disk super block in a buffer.
1112  *
1113  * However, this function is still used to set the fs valid
1114  * flags to 0.  We need to set this flag to 0 since the fs
1115  * may have been checked while mounted and e2fsck may have
1116  * set s_state to EXT2_VALID_FS after some corrections.
1117  */
1118
1119 void ext2_write_super (struct super_block * sb)
1120 {
1121         struct ext2_super_block * es;
1122         lock_kernel();
1123         if (!(sb->s_flags & MS_RDONLY)) {
1124                 es = EXT2_SB(sb)->s_es;
1125
1126                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
1127                         ext2_debug ("setting valid to 0\n");
1128                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
1129                                                   ~EXT2_VALID_FS);
1130                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1131                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1132                         es->s_mtime = cpu_to_le32(get_seconds());
1133                         ext2_sync_super(sb, es);
1134                 } else
1135                         ext2_commit_super (sb, es);
1136         }
1137         sb->s_dirt = 0;
1138         unlock_kernel();
1139 }
1140
1141 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1142 {
1143         struct ext2_sb_info * sbi = EXT2_SB(sb);
1144         struct ext2_super_block * es;
1145         unsigned long old_mount_opt = sbi->s_mount_opt;
1146         struct ext2_mount_options old_opts;
1147         unsigned long old_sb_flags;
1148         int err;
1149
1150         /* Store the old options */
1151         old_sb_flags = sb->s_flags;
1152         old_opts.s_mount_opt = sbi->s_mount_opt;
1153         old_opts.s_resuid = sbi->s_resuid;
1154         old_opts.s_resgid = sbi->s_resgid;
1155
1156         /*
1157          * Allow the "check" option to be passed as a remount option.
1158          */
1159         if (!parse_options (data, sbi)) {
1160                 err = -EINVAL;
1161                 goto restore_opts;
1162         }
1163
1164         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1165                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1166
1167         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
1168                                     EXT2_MOUNT_XIP if not */
1169
1170         if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
1171                 printk("XIP: Unsupported blocksize\n");
1172                 err = -EINVAL;
1173                 goto restore_opts;
1174         }
1175
1176         es = sbi->s_es;
1177         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
1178             (old_mount_opt & EXT2_MOUNT_XIP)) &&
1179             invalidate_inodes(sb))
1180                 ext2_warning(sb, __FUNCTION__, "busy inodes while remounting "\
1181                              "xip remain in cache (no functional problem)");
1182         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1183                 return 0;
1184         if (*flags & MS_RDONLY) {
1185                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1186                     !(sbi->s_mount_state & EXT2_VALID_FS))
1187                         return 0;
1188                 /*
1189                  * OK, we are remounting a valid rw partition rdonly, so set
1190                  * the rdonly flag and then mark the partition as valid again.
1191                  */
1192                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1193                 es->s_mtime = cpu_to_le32(get_seconds());
1194         } else {
1195                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1196                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1197                 if (ret) {
1198                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
1199                                "unsupported optional features (%x).\n",
1200                                sb->s_id, le32_to_cpu(ret));
1201                         err = -EROFS;
1202                         goto restore_opts;
1203                 }
1204                 /*
1205                  * Mounting a RDONLY partition read-write, so reread and
1206                  * store the current valid flag.  (It may have been changed
1207                  * by e2fsck since we originally mounted the partition.)
1208                  */
1209                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1210                 if (!ext2_setup_super (sb, es, 0))
1211                         sb->s_flags &= ~MS_RDONLY;
1212         }
1213         ext2_sync_super(sb, es);
1214         return 0;
1215 restore_opts:
1216         sbi->s_mount_opt = old_opts.s_mount_opt;
1217         sbi->s_resuid = old_opts.s_resuid;
1218         sbi->s_resgid = old_opts.s_resgid;
1219         sb->s_flags = old_sb_flags;
1220         return err;
1221 }
1222
1223 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1224 {
1225         struct super_block *sb = dentry->d_sb;
1226         struct ext2_sb_info *sbi = EXT2_SB(sb);
1227         struct ext2_super_block *es = sbi->s_es;
1228         u64 fsid;
1229
1230         if (test_opt (sb, MINIX_DF))
1231                 sbi->s_overhead_last = 0;
1232         else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1233                 unsigned long i, overhead = 0;
1234                 smp_rmb();
1235
1236                 /*
1237                  * Compute the overhead (FS structures). This is constant
1238                  * for a given filesystem unless the number of block groups
1239                  * changes so we cache the previous value until it does.
1240                  */
1241
1242                 /*
1243                  * All of the blocks before first_data_block are
1244                  * overhead
1245                  */
1246                 overhead = le32_to_cpu(es->s_first_data_block);
1247
1248                 /*
1249                  * Add the overhead attributed to the superblock and
1250                  * block group descriptors.  If the sparse superblocks
1251                  * feature is turned on, then not all groups have this.
1252                  */
1253                 for (i = 0; i < sbi->s_groups_count; i++)
1254                         overhead += ext2_bg_has_super(sb, i) +
1255                                 ext2_bg_num_gdb(sb, i);
1256
1257                 /*
1258                  * Every block group has an inode bitmap, a block
1259                  * bitmap, and an inode table.
1260                  */
1261                 overhead += (sbi->s_groups_count *
1262                              (2 + sbi->s_itb_per_group));
1263                 sbi->s_overhead_last = overhead;
1264                 smp_wmb();
1265                 sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1266         }
1267
1268         buf->f_type = EXT2_SUPER_MAGIC;
1269         buf->f_bsize = sb->s_blocksize;
1270         buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1271         buf->f_bfree = ext2_count_free_blocks(sb);
1272         es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1273         buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1274         if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1275                 buf->f_bavail = 0;
1276         buf->f_files = le32_to_cpu(es->s_inodes_count);
1277         buf->f_ffree = ext2_count_free_inodes(sb);
1278         es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1279         buf->f_namelen = EXT2_NAME_LEN;
1280         fsid = le64_to_cpup((void *)es->s_uuid) ^
1281                le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1282         buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1283         buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1284         return 0;
1285 }
1286
1287 static int ext2_get_sb(struct file_system_type *fs_type,
1288         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1289 {
1290         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super, mnt);
1291 }
1292
1293 #ifdef CONFIG_QUOTA
1294
1295 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1296  * acquiring the locks... As quota files are never truncated and quota code
1297  * itself serializes the operations (and noone else should touch the files)
1298  * we don't have to be afraid of races */
1299 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1300                                size_t len, loff_t off)
1301 {
1302         struct inode *inode = sb_dqopt(sb)->files[type];
1303         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1304         int err = 0;
1305         int offset = off & (sb->s_blocksize - 1);
1306         int tocopy;
1307         size_t toread;
1308         struct buffer_head tmp_bh;
1309         struct buffer_head *bh;
1310         loff_t i_size = i_size_read(inode);
1311
1312         if (off > i_size)
1313                 return 0;
1314         if (off+len > i_size)
1315                 len = i_size-off;
1316         toread = len;
1317         while (toread > 0) {
1318                 tocopy = sb->s_blocksize - offset < toread ?
1319                                 sb->s_blocksize - offset : toread;
1320
1321                 tmp_bh.b_state = 0;
1322                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1323                 if (err < 0)
1324                         return err;
1325                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1326                         memset(data, 0, tocopy);
1327                 else {
1328                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1329                         if (!bh)
1330                                 return -EIO;
1331                         memcpy(data, bh->b_data+offset, tocopy);
1332                         brelse(bh);
1333                 }
1334                 offset = 0;
1335                 toread -= tocopy;
1336                 data += tocopy;
1337                 blk++;
1338         }
1339         return len;
1340 }
1341
1342 /* Write to quotafile */
1343 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1344                                 const char *data, size_t len, loff_t off)
1345 {
1346         struct inode *inode = sb_dqopt(sb)->files[type];
1347         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1348         int err = 0;
1349         int offset = off & (sb->s_blocksize - 1);
1350         int tocopy;
1351         size_t towrite = len;
1352         struct buffer_head tmp_bh;
1353         struct buffer_head *bh;
1354
1355         mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1356         while (towrite > 0) {
1357                 tocopy = sb->s_blocksize - offset < towrite ?
1358                                 sb->s_blocksize - offset : towrite;
1359
1360                 tmp_bh.b_state = 0;
1361                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1362                 if (err < 0)
1363                         goto out;
1364                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1365                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1366                 else
1367                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1368                 if (!bh) {
1369                         err = -EIO;
1370                         goto out;
1371                 }
1372                 lock_buffer(bh);
1373                 memcpy(bh->b_data+offset, data, tocopy);
1374                 flush_dcache_page(bh->b_page);
1375                 set_buffer_uptodate(bh);
1376                 mark_buffer_dirty(bh);
1377                 unlock_buffer(bh);
1378                 brelse(bh);
1379                 offset = 0;
1380                 towrite -= tocopy;
1381                 data += tocopy;
1382                 blk++;
1383         }
1384 out:
1385         if (len == towrite)
1386                 return err;
1387         if (inode->i_size < off+len-towrite)
1388                 i_size_write(inode, off+len-towrite);
1389         inode->i_version++;
1390         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1391         mark_inode_dirty(inode);
1392         mutex_unlock(&inode->i_mutex);
1393         return len - towrite;
1394 }
1395
1396 #endif
1397
1398 static struct file_system_type ext2_fs_type = {
1399         .owner          = THIS_MODULE,
1400         .name           = "ext2",
1401         .get_sb         = ext2_get_sb,
1402         .kill_sb        = kill_block_super,
1403         .fs_flags       = FS_REQUIRES_DEV,
1404 };
1405
1406 static int __init init_ext2_fs(void)
1407 {
1408         int err = init_ext2_xattr();
1409         if (err)
1410                 return err;
1411         err = init_inodecache();
1412         if (err)
1413                 goto out1;
1414         err = register_filesystem(&ext2_fs_type);
1415         if (err)
1416                 goto out;
1417         return 0;
1418 out:
1419         destroy_inodecache();
1420 out1:
1421         exit_ext2_xattr();
1422         return err;
1423 }
1424
1425 static void __exit exit_ext2_fs(void)
1426 {
1427         unregister_filesystem(&ext2_fs_type);
1428         destroy_inodecache();
1429         exit_ext2_xattr();
1430 }
1431
1432 module_init(init_ext2_fs)
1433 module_exit(exit_ext2_fs)