SAFE public projects git trees. - safe/jmp/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 <linux/quotaops.h>
  35 #include <asm/uaccess.h>
  36 #include "ext2.h"
  37 #include "xattr.h"
  38 #include "acl.h"
  39 #include "xip.h"
  40
  41 static void ext2_sync_super(struct super_block *sb,
  42                             struct ext2_super_block *es);
  43 static int ext2_remount (struct super_block * sb, int * flags, char * data);
  44 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
  45
  46 void ext2_error (struct super_block * sb, const char * function,
  47                  const char * fmt, ...)
  48 {
  49         va_list args;
  50         struct ext2_sb_info *sbi = EXT2_SB(sb);
  51         struct ext2_super_block *es = sbi->s_es;
  52
  53         if (!(sb->s_flags & MS_RDONLY)) {
  54                 sbi->s_mount_state |= EXT2_ERROR_FS;
  55                 es->s_state |= cpu_to_le16(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, __func__,
  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         if (!test_opt(sb, RESERVATION))
 289                 seq_puts(seq, ",noreservation");
 290
 291         return 0;
 292 }
 293
 294 #ifdef CONFIG_QUOTA
 295 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
 296 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
 297 #endif
 298
 299 static const struct super_operations ext2_sops = {
 300         .alloc_inode    = ext2_alloc_inode,
 301         .destroy_inode  = ext2_destroy_inode,
 302         .write_inode    = ext2_write_inode,
 303         .delete_inode   = ext2_delete_inode,
 304         .put_super      = ext2_put_super,
 305         .write_super    = ext2_write_super,
 306         .statfs         = ext2_statfs,
 307         .remount_fs     = ext2_remount,
 308         .clear_inode    = ext2_clear_inode,
 309         .show_options   = ext2_show_options,
 310 #ifdef CONFIG_QUOTA
 311         .quota_read     = ext2_quota_read,
 312         .quota_write    = ext2_quota_write,
 313 #endif
 314 };
 315
 316 static struct inode *ext2_nfs_get_inode(struct super_block *sb,
 317                 u64 ino, u32 generation)
 318 {
 319         struct inode *inode;
 320
 321         if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
 322                 return ERR_PTR(-ESTALE);
 323         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
 324                 return ERR_PTR(-ESTALE);
 325
 326         /* iget isn't really right if the inode is currently unallocated!!
 327          * ext2_read_inode currently does appropriate checks, but
 328          * it might be "neater" to call ext2_get_inode first and check
 329          * if the inode is valid.....
 330          */
 331         inode = ext2_iget(sb, ino);
 332         if (IS_ERR(inode))
 333                 return ERR_CAST(inode);
 334         if (generation && inode->i_generation != generation) {
 335                 /* we didn't find the right inode.. */
 336                 iput(inode);
 337                 return ERR_PTR(-ESTALE);
 338         }
 339         return inode;
 340 }
 341
 342 static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 343                 int fh_len, int fh_type)
 344 {
 345         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 346                                     ext2_nfs_get_inode);
 347 }
 348
 349 static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
 350                 int fh_len, int fh_type)
 351 {
 352         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 353                                     ext2_nfs_get_inode);
 354 }
 355
 356 /* Yes, most of these are left as NULL!!
 357  * A NULL value implies the default, which works with ext2-like file
 358  * systems, but can be improved upon.
 359  * Currently only get_parent is required.
 360  */
 361 static const struct export_operations ext2_export_ops = {
 362         .fh_to_dentry = ext2_fh_to_dentry,
 363         .fh_to_parent = ext2_fh_to_parent,
 364         .get_parent = ext2_get_parent,
 365 };
 366
 367 static unsigned long get_sb_block(void **data)
 368 {
 369         unsigned long   sb_block;
 370         char            *options = (char *) *data;
 371
 372         if (!options || strncmp(options, "sb=", 3) != 0)
 373                 return 1;       /* Default location */
 374         options += 3;
 375         sb_block = simple_strtoul(options, &options, 0);
 376         if (*options && *options != ',') {
 377                 printk("EXT2-fs: Invalid sb specification: %s\n",
 378                        (char *) *data);
 379                 return 1;
 380         }
 381         if (*options == ',')
 382                 options++;
 383         *data = (void *) options;
 384         return sb_block;
 385 }
 386
 387 enum {
 388         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
 389         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
 390         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
 391         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
 392         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
 393         Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
 394 };
 395
 396 static match_table_t tokens = {
 397         {Opt_bsd_df, "bsddf"},
 398         {Opt_minix_df, "minixdf"},
 399         {Opt_grpid, "grpid"},
 400         {Opt_grpid, "bsdgroups"},
 401         {Opt_nogrpid, "nogrpid"},
 402         {Opt_nogrpid, "sysvgroups"},
 403         {Opt_resgid, "resgid=%u"},
 404         {Opt_resuid, "resuid=%u"},
 405         {Opt_sb, "sb=%u"},
 406         {Opt_err_cont, "errors=continue"},
 407         {Opt_err_panic, "errors=panic"},
 408         {Opt_err_ro, "errors=remount-ro"},
 409         {Opt_nouid32, "nouid32"},
 410         {Opt_nocheck, "check=none"},
 411         {Opt_nocheck, "nocheck"},
 412         {Opt_debug, "debug"},
 413         {Opt_oldalloc, "oldalloc"},
 414         {Opt_orlov, "orlov"},
 415         {Opt_nobh, "nobh"},
 416         {Opt_user_xattr, "user_xattr"},
 417         {Opt_nouser_xattr, "nouser_xattr"},
 418         {Opt_acl, "acl"},
 419         {Opt_noacl, "noacl"},
 420         {Opt_xip, "xip"},
 421         {Opt_grpquota, "grpquota"},
 422         {Opt_ignore, "noquota"},
 423         {Opt_quota, "quota"},
 424         {Opt_usrquota, "usrquota"},
 425         {Opt_reservation, "reservation"},
 426         {Opt_noreservation, "noreservation"},
 427         {Opt_err, NULL}
 428 };
 429
 430 static int parse_options (char * options,
 431                           struct ext2_sb_info *sbi)
 432 {
 433         char * p;
 434         substring_t args[MAX_OPT_ARGS];
 435         int option;
 436
 437         if (!options)
 438                 return 1;
 439
 440         while ((p = strsep (&options, ",")) != NULL) {
 441                 int token;
 442                 if (!*p)
 443                         continue;
 444
 445                 token = match_token(p, tokens, args);
 446                 switch (token) {
 447                 case Opt_bsd_df:
 448                         clear_opt (sbi->s_mount_opt, MINIX_DF);
 449                         break;
 450                 case Opt_minix_df:
 451                         set_opt (sbi->s_mount_opt, MINIX_DF);
 452                         break;
 453                 case Opt_grpid:
 454                         set_opt (sbi->s_mount_opt, GRPID);
 455                         break;
 456                 case Opt_nogrpid:
 457                         clear_opt (sbi->s_mount_opt, GRPID);
 458                         break;
 459                 case Opt_resuid:
 460                         if (match_int(&args[0], &option))
 461                                 return 0;
 462                         sbi->s_resuid = option;
 463                         break;
 464                 case Opt_resgid:
 465                         if (match_int(&args[0], &option))
 466                                 return 0;
 467                         sbi->s_resgid = option;
 468                         break;
 469                 case Opt_sb:
 470                         /* handled by get_sb_block() instead of here */
 471                         /* *sb_block = match_int(&args[0]); */
 472                         break;
 473                 case Opt_err_panic:
 474                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 475                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
 476                         set_opt (sbi->s_mount_opt, ERRORS_PANIC);
 477                         break;
 478                 case Opt_err_ro:
 479                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 480                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 481                         set_opt (sbi->s_mount_opt, ERRORS_RO);
 482                         break;
 483                 case Opt_err_cont:
 484                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
 485                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 486                         set_opt (sbi->s_mount_opt, ERRORS_CONT);
 487                         break;
 488                 case Opt_nouid32:
 489                         set_opt (sbi->s_mount_opt, NO_UID32);
 490                         break;
 491                 case Opt_nocheck:
 492                         clear_opt (sbi->s_mount_opt, CHECK);
 493                         break;
 494                 case Opt_debug:
 495                         set_opt (sbi->s_mount_opt, DEBUG);
 496                         break;
 497                 case Opt_oldalloc:
 498                         set_opt (sbi->s_mount_opt, OLDALLOC);
 499                         break;
 500                 case Opt_orlov:
 501                         clear_opt (sbi->s_mount_opt, OLDALLOC);
 502                         break;
 503                 case Opt_nobh:
 504                         set_opt (sbi->s_mount_opt, NOBH);
 505                         break;
 506 #ifdef CONFIG_EXT2_FS_XATTR
 507                 case Opt_user_xattr:
 508                         set_opt (sbi->s_mount_opt, XATTR_USER);
 509                         break;
 510                 case Opt_nouser_xattr:
 511                         clear_opt (sbi->s_mount_opt, XATTR_USER);
 512                         break;
 513 #else
 514                 case Opt_user_xattr:
 515                 case Opt_nouser_xattr:
 516                         printk("EXT2 (no)user_xattr options not supported\n");
 517                         break;
 518 #endif
 519 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 520                 case Opt_acl:
 521                         set_opt(sbi->s_mount_opt, POSIX_ACL);
 522                         break;
 523                 case Opt_noacl:
 524                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
 525                         break;
 526 #else
 527                 case Opt_acl:
 528                 case Opt_noacl:
 529                         printk("EXT2 (no)acl options not supported\n");
 530                         break;
 531 #endif
 532                 case Opt_xip:
 533 #ifdef CONFIG_EXT2_FS_XIP
 534                         set_opt (sbi->s_mount_opt, XIP);
 535 #else
 536                         printk("EXT2 xip option not supported\n");
 537 #endif
 538                         break;
 539
 540 #if defined(CONFIG_QUOTA)
 541                 case Opt_quota:
 542                 case Opt_usrquota:
 543                         set_opt(sbi->s_mount_opt, USRQUOTA);
 544                         break;
 545
 546                 case Opt_grpquota:
 547                         set_opt(sbi->s_mount_opt, GRPQUOTA);
 548                         break;
 549 #else
 550                 case Opt_quota:
 551                 case Opt_usrquota:
 552                 case Opt_grpquota:
 553                         printk(KERN_ERR
 554                                 "EXT2-fs: quota operations not supported.\n");
 555
 556                         break;
 557 #endif
 558
 559                 case Opt_reservation:
 560                         set_opt(sbi->s_mount_opt, RESERVATION);
 561                         printk("reservations ON\n");
 562                         break;
 563                 case Opt_noreservation:
 564                         clear_opt(sbi->s_mount_opt, RESERVATION);
 565                         printk("reservations OFF\n");
 566                         break;
 567                 case Opt_ignore:
 568                         break;
 569                 default:
 570                         return 0;
 571                 }
 572         }
 573         return 1;
 574 }
 575
 576 static int ext2_setup_super (struct super_block * sb,
 577                               struct ext2_super_block * es,
 578                               int read_only)
 579 {
 580         int res = 0;
 581         struct ext2_sb_info *sbi = EXT2_SB(sb);
 582
 583         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 584                 printk ("EXT2-fs warning: revision level too high, "
 585                         "forcing read-only mode\n");
 586                 res = MS_RDONLY;
 587         }
 588         if (read_only)
 589                 return res;
 590         if (!(sbi->s_mount_state & EXT2_VALID_FS))
 591                 printk ("EXT2-fs warning: mounting unchecked fs, "
 592                         "running e2fsck is recommended\n");
 593         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 594                 printk ("EXT2-fs warning: mounting fs with errors, "
 595                         "running e2fsck is recommended\n");
 596         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 597                  le16_to_cpu(es->s_mnt_count) >=
 598                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 599                 printk ("EXT2-fs warning: maximal mount count reached, "
 600                         "running e2fsck is recommended\n");
 601         else if (le32_to_cpu(es->s_checkinterval) &&
 602                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 603                 printk ("EXT2-fs warning: checktime reached, "
 604                         "running e2fsck is recommended\n");
 605         if (!le16_to_cpu(es->s_max_mnt_count))
 606                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 607         le16_add_cpu(&es->s_mnt_count, 1);
 608         ext2_write_super(sb);
 609         if (test_opt (sb, DEBUG))
 610                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
 611                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
 612                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 613                         sbi->s_frag_size,
 614                         sbi->s_groups_count,
 615                         EXT2_BLOCKS_PER_GROUP(sb),
 616                         EXT2_INODES_PER_GROUP(sb),
 617                         sbi->s_mount_opt);
 618         return res;
 619 }
 620
 621 static int ext2_check_descriptors(struct super_block *sb)
 622 {
 623         int i;
 624         struct ext2_sb_info *sbi = EXT2_SB(sb);
 625
 626         ext2_debug ("Checking group descriptors");
 627
 628         for (i = 0; i < sbi->s_groups_count; i++) {
 629                 struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
 630                 ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
 631                 ext2_fsblk_t last_block;
 632
 633                 if (i == sbi->s_groups_count - 1)
 634                         last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
 635                 else
 636                         last_block = first_block +
 637                                 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
 638
 639                 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
 640                     le32_to_cpu(gdp->bg_block_bitmap) > last_block)
 641                 {
 642                         ext2_error (sb, "ext2_check_descriptors",
 643                                     "Block bitmap for group %d"
 644                                     " not in group (block %lu)!",
 645                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 646                         return 0;
 647                 }
 648                 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
 649                     le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
 650                 {
 651                         ext2_error (sb, "ext2_check_descriptors",
 652                                     "Inode bitmap for group %d"
 653                                     " not in group (block %lu)!",
 654                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 655                         return 0;
 656                 }
 657                 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
 658                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
 659                     last_block)
 660                 {
 661                         ext2_error (sb, "ext2_check_descriptors",
 662                                     "Inode table for group %d"
 663                                     " not in group (block %lu)!",
 664                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 665                         return 0;
 666                 }
 667         }
 668         return 1;
 669 }
 670
 671 /*
 672  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 673  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 674  * We need to be 1 filesystem block less than the 2^32 sector limit.
 675  */
 676 static loff_t ext2_max_size(int bits)
 677 {
 678         loff_t res = EXT2_NDIR_BLOCKS;
 679         int meta_blocks;
 680         loff_t upper_limit;
 681
 682         /* This is calculated to be the largest file size for a
 683          * dense, file such that the total number of
 684          * sectors in the file, including data and all indirect blocks,
 685          * does not exceed 2^32 -1
 686          * __u32 i_blocks representing the total number of
 687          * 512 bytes blocks of the file
 688          */
 689         upper_limit = (1LL << 32) - 1;
 690
 691         /* total blocks in file system block size */
 692         upper_limit >>= (bits - 9);
 693
 694
 695         /* indirect blocks */
 696         meta_blocks = 1;
 697         /* double indirect blocks */
 698         meta_blocks += 1 + (1LL << (bits-2));
 699         /* tripple indirect blocks */
 700         meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
 701
 702         upper_limit -= meta_blocks;
 703         upper_limit <<= bits;
 704
 705         res += 1LL << (bits-2);
 706         res += 1LL << (2*(bits-2));
 707         res += 1LL << (3*(bits-2));
 708         res <<= bits;
 709         if (res > upper_limit)
 710                 res = upper_limit;
 711
 712         if (res > MAX_LFS_FILESIZE)
 713                 res = MAX_LFS_FILESIZE;
 714
 715         return res;
 716 }
 717
 718 static unsigned long descriptor_loc(struct super_block *sb,
 719                                     unsigned long logic_sb_block,
 720                                     int nr)
 721 {
 722         struct ext2_sb_info *sbi = EXT2_SB(sb);
 723         unsigned long bg, first_meta_bg;
 724         int has_super = 0;
 725
 726         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 727
 728         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 729             nr < first_meta_bg)
 730                 return (logic_sb_block + nr + 1);
 731         bg = sbi->s_desc_per_block * nr;
 732         if (ext2_bg_has_super(sb, bg))
 733                 has_super = 1;
 734
 735         return ext2_group_first_block_no(sb, bg) + has_super;
 736 }
 737
 738 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 739 {
 740         struct buffer_head * bh;
 741         struct ext2_sb_info * sbi;
 742         struct ext2_super_block * es;
 743         struct inode *root;
 744         unsigned long block;
 745         unsigned long sb_block = get_sb_block(&data);
 746         unsigned long logic_sb_block;
 747         unsigned long offset = 0;
 748         unsigned long def_mount_opts;
 749         long ret = -EINVAL;
 750         int blocksize = BLOCK_SIZE;
 751         int db_count;
 752         int i, j;
 753         __le32 features;
 754         int err;
 755
 756         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 757         if (!sbi)
 758                 return -ENOMEM;
 759         sb->s_fs_info = sbi;
 760         sbi->s_sb_block = sb_block;
 761
 762         /*
 763          * See what the current blocksize for the device is, and
 764          * use that as the blocksize.  Otherwise (or if the blocksize
 765          * is smaller than the default) use the default.
 766          * This is important for devices that have a hardware
 767          * sectorsize that is larger than the default.
 768          */
 769         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 770         if (!blocksize) {
 771                 printk ("EXT2-fs: unable to set blocksize\n");
 772                 goto failed_sbi;
 773         }
 774
 775         /*
 776          * If the superblock doesn't start on a hardware sector boundary,
 777          * calculate the offset.
 778          */
 779         if (blocksize != BLOCK_SIZE) {
 780                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 781                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 782         } else {
 783                 logic_sb_block = sb_block;
 784         }
 785
 786         if (!(bh = sb_bread(sb, logic_sb_block))) {
 787                 printk ("EXT2-fs: unable to read superblock\n");
 788                 goto failed_sbi;
 789         }
 790         /*
 791          * Note: s_es must be initialized as soon as possible because
 792          *       some ext2 macro-instructions depend on its value
 793          */
 794         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 795         sbi->s_es = es;
 796         sb->s_magic = le16_to_cpu(es->s_magic);
 797
 798         if (sb->s_magic != EXT2_SUPER_MAGIC)
 799                 goto cantfind_ext2;
 800
 801         /* Set defaults before we parse the mount options */
 802         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 803         if (def_mount_opts & EXT2_DEFM_DEBUG)
 804                 set_opt(sbi->s_mount_opt, DEBUG);
 805         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 806                 set_opt(sbi->s_mount_opt, GRPID);
 807         if (def_mount_opts & EXT2_DEFM_UID16)
 808                 set_opt(sbi->s_mount_opt, NO_UID32);
 809 #ifdef CONFIG_EXT2_FS_XATTR
 810         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 811                 set_opt(sbi->s_mount_opt, XATTR_USER);
 812 #endif
 813 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 814         if (def_mount_opts & EXT2_DEFM_ACL)
 815                 set_opt(sbi->s_mount_opt, POSIX_ACL);
 816 #endif
 817
 818         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 819                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 820         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
 821                 set_opt(sbi->s_mount_opt, ERRORS_CONT);
 822         else
 823                 set_opt(sbi->s_mount_opt, ERRORS_RO);
 824
 825         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
 826         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
 827
 828         set_opt(sbi->s_mount_opt, RESERVATION);
 829
 830         if (!parse_options ((char *) data, sbi))
 831                 goto failed_mount;
 832
 833         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 834                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 835                  MS_POSIXACL : 0);
 836
 837         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
 838                                     EXT2_MOUNT_XIP if not */
 839
 840         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 841             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 842              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 843              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 844                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
 845                        "running e2fsck is recommended\n");
 846         /*
 847          * Check feature flags regardless of the revision level, since we
 848          * previously didn't change the revision level when setting the flags,
 849          * so there is a chance incompat flags are set on a rev 0 filesystem.
 850          */
 851         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 852         if (features) {
 853                 printk("EXT2-fs: %s: couldn't mount because of "
 854                        "unsupported optional features (%x).\n",
 855                        sb->s_id, le32_to_cpu(features));
 856                 goto failed_mount;
 857         }
 858         if (!(sb->s_flags & MS_RDONLY) &&
 859             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 860                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
 861                        "unsupported optional features (%x).\n",
 862                        sb->s_id, le32_to_cpu(features));
 863                 goto failed_mount;
 864         }
 865
 866         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 867
 868         if (ext2_use_xip(sb) && blocksize != PAGE_SIZE) {
 869                 if (!silent)
 870                         printk("XIP: Unsupported blocksize\n");
 871                 goto failed_mount;
 872         }
 873
 874         /* If the blocksize doesn't match, re-read the thing.. */
 875         if (sb->s_blocksize != blocksize) {
 876                 brelse(bh);
 877
 878                 if (!sb_set_blocksize(sb, blocksize)) {
 879                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
 880                         goto failed_sbi;
 881                 }
 882
 883                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 884                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 885                 bh = sb_bread(sb, logic_sb_block);
 886                 if(!bh) {
 887                         printk("EXT2-fs: Couldn't read superblock on "
 888                                "2nd try.\n");
 889                         goto failed_sbi;
 890                 }
 891                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 892                 sbi->s_es = es;
 893                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 894                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
 895                         goto failed_mount;
 896                 }
 897         }
 898
 899         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 900
 901         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 902                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 903                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 904         } else {
 905                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 906                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 907                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 908                     !is_power_of_2(sbi->s_inode_size) ||
 909                     (sbi->s_inode_size > blocksize)) {
 910                         printk ("EXT2-fs: unsupported inode size: %d\n",
 911                                 sbi->s_inode_size);
 912                         goto failed_mount;
 913                 }
 914         }
 915
 916         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 917                                    le32_to_cpu(es->s_log_frag_size);
 918         if (sbi->s_frag_size == 0)
 919                 goto cantfind_ext2;
 920         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
 921
 922         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 923         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 924         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 925
 926         if (EXT2_INODE_SIZE(sb) == 0)
 927                 goto cantfind_ext2;
 928         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
 929         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
 930                 goto cantfind_ext2;
 931         sbi->s_itb_per_group = sbi->s_inodes_per_group /
 932                                         sbi->s_inodes_per_block;
 933         sbi->s_desc_per_block = sb->s_blocksize /
 934                                         sizeof (struct ext2_group_desc);
 935         sbi->s_sbh = bh;
 936         sbi->s_mount_state = le16_to_cpu(es->s_state);
 937         sbi->s_addr_per_block_bits =
 938                 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
 939         sbi->s_desc_per_block_bits =
 940                 ilog2 (EXT2_DESC_PER_BLOCK(sb));
 941
 942         if (sb->s_magic != EXT2_SUPER_MAGIC)
 943                 goto cantfind_ext2;
 944
 945         if (sb->s_blocksize != bh->b_size) {
 946                 if (!silent)
 947                         printk ("VFS: Unsupported blocksize on dev "
 948                                 "%s.\n", sb->s_id);
 949                 goto failed_mount;
 950         }
 951
 952         if (sb->s_blocksize != sbi->s_frag_size) {
 953                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
 954                         sbi->s_frag_size, sb->s_blocksize);
 955                 goto failed_mount;
 956         }
 957
 958         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
 959                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
 960                         sbi->s_blocks_per_group);
 961                 goto failed_mount;
 962         }
 963         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 964                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
 965                         sbi->s_frags_per_group);
 966                 goto failed_mount;
 967         }
 968         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
 969                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
 970                         sbi->s_inodes_per_group);
 971                 goto failed_mount;
 972         }
 973
 974         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
 975                 goto cantfind_ext2;
 976         sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
 977                                 le32_to_cpu(es->s_first_data_block) - 1)
 978                                         / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
 979         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
 980                    EXT2_DESC_PER_BLOCK(sb);
 981         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
 982         if (sbi->s_group_desc == NULL) {
 983                 printk ("EXT2-fs: not enough memory\n");
 984                 goto failed_mount;
 985         }
 986         bgl_lock_init(&sbi->s_blockgroup_lock);
 987         sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
 988         if (!sbi->s_debts) {
 989                 printk ("EXT2-fs: not enough memory\n");
 990                 goto failed_mount_group_desc;
 991         }
 992         for (i = 0; i < db_count; i++) {
 993                 block = descriptor_loc(sb, logic_sb_block, i);
 994                 sbi->s_group_desc[i] = sb_bread(sb, block);
 995                 if (!sbi->s_group_desc[i]) {
 996                         for (j = 0; j < i; j++)
 997                                 brelse (sbi->s_group_desc[j]);
 998                         printk ("EXT2-fs: unable to read group descriptors\n");
 999                         goto failed_mount_group_desc;
1000                 }
1001         }
1002         if (!ext2_check_descriptors (sb)) {
1003                 printk ("EXT2-fs: group descriptors corrupted!\n");
1004                 goto failed_mount2;
1005         }
1006         sbi->s_gdb_count = db_count;
1007         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1008         spin_lock_init(&sbi->s_next_gen_lock);
1009
1010         /* per fileystem reservation list head & lock */
1011         spin_lock_init(&sbi->s_rsv_window_lock);
1012         sbi->s_rsv_window_root = RB_ROOT;
1013         /*
1014          * Add a single, static dummy reservation to the start of the
1015          * reservation window list --- it gives us a placeholder for
1016          * append-at-start-of-list which makes the allocation logic
1017          * _much_ simpler.
1018          */
1019         sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1020         sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1021         sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1022         sbi->s_rsv_window_head.rsv_goal_size = 0;
1023         ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1024
1025         err = percpu_counter_init(&sbi->s_freeblocks_counter,
1026                                 ext2_count_free_blocks(sb));
1027         if (!err) {
1028                 err = percpu_counter_init(&sbi->s_freeinodes_counter,
1029                                 ext2_count_free_inodes(sb));
1030         }
1031         if (!err) {
1032                 err = percpu_counter_init(&sbi->s_dirs_counter,
1033                                 ext2_count_dirs(sb));
1034         }
1035         if (err) {
1036                 printk(KERN_ERR "EXT2-fs: insufficient memory\n");
1037                 goto failed_mount3;
1038         }
1039         /*
1040          * set up enough so that it can read an inode
1041          */
1042         sb->s_op = &ext2_sops;
1043         sb->s_export_op = &ext2_export_ops;
1044         sb->s_xattr = ext2_xattr_handlers;
1045         root = ext2_iget(sb, EXT2_ROOT_INO);
1046         if (IS_ERR(root)) {
1047                 ret = PTR_ERR(root);
1048                 goto failed_mount3;
1049         }
1050         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1051                 iput(root);
1052                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
1053                 goto failed_mount3;
1054         }
1055
1056         sb->s_root = d_alloc_root(root);
1057         if (!sb->s_root) {
1058                 iput(root);
1059                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
1060                 ret = -ENOMEM;
1061                 goto failed_mount3;
1062         }
1063         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1064                 ext2_warning(sb, __func__,
1065                         "mounting ext3 filesystem as ext2");
1066         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
1067         return 0;
1068
1069 cantfind_ext2:
1070         if (!silent)
1071                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
1072                        sb->s_id);
1073         goto failed_mount;
1074 failed_mount3:
1075         percpu_counter_destroy(&sbi->s_freeblocks_counter);
1076         percpu_counter_destroy(&sbi->s_freeinodes_counter);
1077         percpu_counter_destroy(&sbi->s_dirs_counter);
1078 failed_mount2:
1079         for (i = 0; i < db_count; i++)
1080                 brelse(sbi->s_group_desc[i]);
1081 failed_mount_group_desc:
1082         kfree(sbi->s_group_desc);
1083         kfree(sbi->s_debts);
1084 failed_mount:
1085         brelse(bh);
1086 failed_sbi:
1087         sb->s_fs_info = NULL;
1088         kfree(sbi);
1089         return ret;
1090 }
1091
1092 static void ext2_commit_super (struct super_block * sb,
1093                                struct ext2_super_block * es)
1094 {
1095         es->s_wtime = cpu_to_le32(get_seconds());
1096         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1097         sb->s_dirt = 0;
1098 }
1099
1100 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
1101 {
1102         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1103         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1104         es->s_wtime = cpu_to_le32(get_seconds());
1105         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1106         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1107         sb->s_dirt = 0;
1108 }
1109
1110 /*
1111  * In the second extended file system, it is not necessary to
1112  * write the super block since we use a mapping of the
1113  * disk super block in a buffer.
1114  *
1115  * However, this function is still used to set the fs valid
1116  * flags to 0.  We need to set this flag to 0 since the fs
1117  * may have been checked while mounted and e2fsck may have
1118  * set s_state to EXT2_VALID_FS after some corrections.
1119  */
1120
1121 void ext2_write_super (struct super_block * sb)
1122 {
1123         struct ext2_super_block * es;
1124         lock_kernel();
1125         if (!(sb->s_flags & MS_RDONLY)) {
1126                 es = EXT2_SB(sb)->s_es;
1127
1128                 if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1129                         ext2_debug ("setting valid to 0\n");
1130                         es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1131                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1132                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1133                         es->s_mtime = cpu_to_le32(get_seconds());
1134                         ext2_sync_super(sb, es);
1135                 } else
1136                         ext2_commit_super (sb, es);
1137         }
1138         sb->s_dirt = 0;
1139         unlock_kernel();
1140 }
1141
1142 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1143 {
1144         struct ext2_sb_info * sbi = EXT2_SB(sb);
1145         struct ext2_super_block * es;
1146         unsigned long old_mount_opt = sbi->s_mount_opt;
1147         struct ext2_mount_options old_opts;
1148         unsigned long old_sb_flags;
1149         int err;
1150
1151         /* Store the old options */
1152         old_sb_flags = sb->s_flags;
1153         old_opts.s_mount_opt = sbi->s_mount_opt;
1154         old_opts.s_resuid = sbi->s_resuid;
1155         old_opts.s_resgid = sbi->s_resgid;
1156
1157         /*
1158          * Allow the "check" option to be passed as a remount option.
1159          */
1160         if (!parse_options (data, sbi)) {
1161                 err = -EINVAL;
1162                 goto restore_opts;
1163         }
1164
1165         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1166                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1167
1168         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
1169                                     EXT2_MOUNT_XIP if not */
1170
1171         if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
1172                 printk("XIP: Unsupported blocksize\n");
1173                 err = -EINVAL;
1174                 goto restore_opts;
1175         }
1176
1177         es = sbi->s_es;
1178         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
1179             (old_mount_opt & EXT2_MOUNT_XIP)) &&
1180             invalidate_inodes(sb))
1181                 ext2_warning(sb, __func__, "busy inodes while remounting "\
1182                              "xip remain in cache (no functional problem)");
1183         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1184                 return 0;
1185         if (*flags & MS_RDONLY) {
1186                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1187                     !(sbi->s_mount_state & EXT2_VALID_FS))
1188                         return 0;
1189                 /*
1190                  * OK, we are remounting a valid rw partition rdonly, so set
1191                  * the rdonly flag and then mark the partition as valid again.
1192                  */
1193                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1194                 es->s_mtime = cpu_to_le32(get_seconds());
1195         } else {
1196                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1197                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1198                 if (ret) {
1199                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
1200                                "unsupported optional features (%x).\n",
1201                                sb->s_id, le32_to_cpu(ret));
1202                         err = -EROFS;
1203                         goto restore_opts;
1204                 }
1205                 /*
1206                  * Mounting a RDONLY partition read-write, so reread and
1207                  * store the current valid flag.  (It may have been changed
1208                  * by e2fsck since we originally mounted the partition.)
1209                  */
1210                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1211                 if (!ext2_setup_super (sb, es, 0))
1212                         sb->s_flags &= ~MS_RDONLY;
1213         }
1214         ext2_sync_super(sb, es);
1215         return 0;
1216 restore_opts:
1217         sbi->s_mount_opt = old_opts.s_mount_opt;
1218         sbi->s_resuid = old_opts.s_resuid;
1219         sbi->s_resgid = old_opts.s_resgid;
1220         sb->s_flags = old_sb_flags;
1221         return err;
1222 }
1223
1224 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1225 {
1226         struct super_block *sb = dentry->d_sb;
1227         struct ext2_sb_info *sbi = EXT2_SB(sb);
1228         struct ext2_super_block *es = sbi->s_es;
1229         u64 fsid;
1230
1231         if (test_opt (sb, MINIX_DF))
1232                 sbi->s_overhead_last = 0;
1233         else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1234                 unsigned long i, overhead = 0;
1235                 smp_rmb();
1236
1237                 /*
1238                  * Compute the overhead (FS structures). This is constant
1239                  * for a given filesystem unless the number of block groups
1240                  * changes so we cache the previous value until it does.
1241                  */
1242
1243                 /*
1244                  * All of the blocks before first_data_block are
1245                  * overhead
1246                  */
1247                 overhead = le32_to_cpu(es->s_first_data_block);
1248
1249                 /*
1250                  * Add the overhead attributed to the superblock and
1251                  * block group descriptors.  If the sparse superblocks
1252                  * feature is turned on, then not all groups have this.
1253                  */
1254                 for (i = 0; i < sbi->s_groups_count; i++)
1255                         overhead += ext2_bg_has_super(sb, i) +
1256                                 ext2_bg_num_gdb(sb, i);
1257
1258                 /*
1259                  * Every block group has an inode bitmap, a block
1260                  * bitmap, and an inode table.
1261                  */
1262                 overhead += (sbi->s_groups_count *
1263                              (2 + sbi->s_itb_per_group));
1264                 sbi->s_overhead_last = overhead;
1265                 smp_wmb();
1266                 sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1267         }
1268
1269         buf->f_type = EXT2_SUPER_MAGIC;
1270         buf->f_bsize = sb->s_blocksize;
1271         buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1272         buf->f_bfree = ext2_count_free_blocks(sb);
1273         es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1274         buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1275         if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1276                 buf->f_bavail = 0;
1277         buf->f_files = le32_to_cpu(es->s_inodes_count);
1278         buf->f_ffree = ext2_count_free_inodes(sb);
1279         es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1280         buf->f_namelen = EXT2_NAME_LEN;
1281         fsid = le64_to_cpup((void *)es->s_uuid) ^
1282                le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1283         buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1284         buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1285         return 0;
1286 }
1287
1288 static int ext2_get_sb(struct file_system_type *fs_type,
1289         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1290 {
1291         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super, mnt);
1292 }
1293
1294 #ifdef CONFIG_QUOTA
1295
1296 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1297  * acquiring the locks... As quota files are never truncated and quota code
1298  * itself serializes the operations (and noone else should touch the files)
1299  * we don't have to be afraid of races */
1300 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1301                                size_t len, loff_t off)
1302 {
1303         struct inode *inode = sb_dqopt(sb)->files[type];
1304         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1305         int err = 0;
1306         int offset = off & (sb->s_blocksize - 1);
1307         int tocopy;
1308         size_t toread;
1309         struct buffer_head tmp_bh;
1310         struct buffer_head *bh;
1311         loff_t i_size = i_size_read(inode);
1312
1313         if (off > i_size)
1314                 return 0;
1315         if (off+len > i_size)
1316                 len = i_size-off;
1317         toread = len;
1318         while (toread > 0) {
1319                 tocopy = sb->s_blocksize - offset < toread ?
1320                                 sb->s_blocksize - offset : toread;
1321
1322                 tmp_bh.b_state = 0;
1323                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1324                 if (err < 0)
1325                         return err;
1326                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1327                         memset(data, 0, tocopy);
1328                 else {
1329                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1330                         if (!bh)
1331                                 return -EIO;
1332                         memcpy(data, bh->b_data+offset, tocopy);
1333                         brelse(bh);
1334                 }
1335                 offset = 0;
1336                 toread -= tocopy;
1337                 data += tocopy;
1338                 blk++;
1339         }
1340         return len;
1341 }
1342
1343 /* Write to quotafile */
1344 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1345                                 const char *data, size_t len, loff_t off)
1346 {
1347         struct inode *inode = sb_dqopt(sb)->files[type];
1348         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1349         int err = 0;
1350         int offset = off & (sb->s_blocksize - 1);
1351         int tocopy;
1352         size_t towrite = len;
1353         struct buffer_head tmp_bh;
1354         struct buffer_head *bh;
1355
1356         mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1357         while (towrite > 0) {
1358                 tocopy = sb->s_blocksize - offset < towrite ?
1359                                 sb->s_blocksize - offset : towrite;
1360
1361                 tmp_bh.b_state = 0;
1362                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1363                 if (err < 0)
1364                         goto out;
1365                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1366                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1367                 else
1368                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1369                 if (!bh) {
1370                         err = -EIO;
1371                         goto out;
1372                 }
1373                 lock_buffer(bh);
1374                 memcpy(bh->b_data+offset, data, tocopy);
1375                 flush_dcache_page(bh->b_page);
1376                 set_buffer_uptodate(bh);
1377                 mark_buffer_dirty(bh);
1378                 unlock_buffer(bh);
1379                 brelse(bh);
1380                 offset = 0;
1381                 towrite -= tocopy;
1382                 data += tocopy;
1383                 blk++;
1384         }
1385 out:
1386         if (len == towrite)
1387                 return err;
1388         if (inode->i_size < off+len-towrite)
1389                 i_size_write(inode, off+len-towrite);
1390         inode->i_version++;
1391         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1392         mark_inode_dirty(inode);
1393         mutex_unlock(&inode->i_mutex);
1394         return len - towrite;
1395 }
1396
1397 #endif
1398
1399 static struct file_system_type ext2_fs_type = {
1400         .owner          = THIS_MODULE,
1401         .name           = "ext2",
1402         .get_sb         = ext2_get_sb,
1403         .kill_sb        = kill_block_super,
1404         .fs_flags       = FS_REQUIRES_DEV,
1405 };
1406
1407 static int __init init_ext2_fs(void)
1408 {
1409         int err = init_ext2_xattr();
1410         if (err)
1411                 return err;
1412         err = init_inodecache();
1413         if (err)
1414                 goto out1;
1415         err = register_filesystem(&ext2_fs_type);
1416         if (err)
1417                 goto out;
1418         return 0;
1419 out:
1420         destroy_inodecache();
1421 out1:
1422         exit_ext2_xattr();
1423         return err;
1424 }
1425
1426 static void __exit exit_ext2_fs(void)
1427 {
1428         unregister_filesystem(&ext2_fs_type);
1429         destroy_inodecache();
1430         exit_ext2_xattr();
1431 }
1432
1433 module_init(init_ext2_fs)
1434 module_exit(exit_ext2_fs)