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/vfs.h>
  30 #include <linux/seq_file.h>
  31 #include <linux/mount.h>
  32 #include <linux/log2.h>
  33 #include <linux/quotaops.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, int wait);
  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 static int ext2_sync_fs(struct super_block *sb, int wait);
  45
  46 void ext2_error(struct super_block *sb, const char *function,
  47                 const char *fmt, ...)
  48 {
  49         struct va_format vaf;
  50         va_list args;
  51         struct ext2_sb_info *sbi = EXT2_SB(sb);
  52         struct ext2_super_block *es = sbi->s_es;
  53
  54         if (!(sb->s_flags & MS_RDONLY)) {
  55                 spin_lock(&sbi->s_lock);
  56                 sbi->s_mount_state |= EXT2_ERROR_FS;
  57                 es->s_state |= cpu_to_le16(EXT2_ERROR_FS);
  58                 spin_unlock(&sbi->s_lock);
  59                 ext2_sync_super(sb, es, 1);
  60         }
  61
  62         va_start(args, fmt);
  63
  64         vaf.fmt = fmt;
  65         vaf.va = &args;
  66
  67         printk(KERN_CRIT "EXT2-fs (%s): error: %s: %pV\n",
  68                sb->s_id, function, &vaf);
  69
  70         va_end(args);
  71
  72         if (test_opt(sb, ERRORS_PANIC))
  73                 panic("EXT2-fs: panic from previous error\n");
  74         if (test_opt(sb, ERRORS_RO)) {
  75                 ext2_msg(sb, KERN_CRIT,
  76                              "error: remounting filesystem read-only");
  77                 sb->s_flags |= MS_RDONLY;
  78         }
  79 }
  80
  81 void ext2_msg(struct super_block *sb, const char *prefix,
  82                 const char *fmt, ...)
  83 {
  84         struct va_format vaf;
  85         va_list args;
  86
  87         va_start(args, fmt);
  88
  89         vaf.fmt = fmt;
  90         vaf.va = &args;
  91
  92         printk("%sEXT2-fs (%s): %pV\n", prefix, sb->s_id, &vaf);
  93
  94         va_end(args);
  95 }
  96
  97 /*
  98  * This must be called with sbi->s_lock held.
  99  */
 100 void ext2_update_dynamic_rev(struct super_block *sb)
 101 {
 102         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
 103
 104         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
 105                 return;
 106
 107         ext2_msg(sb, KERN_WARNING,
 108                      "warning: updating to rev %d because of "
 109                      "new feature flag, running e2fsck is recommended",
 110                      EXT2_DYNAMIC_REV);
 111
 112         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
 113         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
 114         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
 115         /* leave es->s_feature_*compat flags alone */
 116         /* es->s_uuid will be set by e2fsck if empty */
 117
 118         /*
 119          * The rest of the superblock fields should be zero, and if not it
 120          * means they are likely already in use, so leave them alone.  We
 121          * can leave it up to e2fsck to clean up any inconsistencies there.
 122          */
 123 }
 124
 125 static void ext2_put_super (struct super_block * sb)
 126 {
 127         int db_count;
 128         int i;
 129         struct ext2_sb_info *sbi = EXT2_SB(sb);
 130
 131         dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
 132
 133         ext2_xattr_put_super(sb);
 134         if (!(sb->s_flags & MS_RDONLY)) {
 135                 struct ext2_super_block *es = sbi->s_es;
 136
 137                 spin_lock(&sbi->s_lock);
 138                 es->s_state = cpu_to_le16(sbi->s_mount_state);
 139                 spin_unlock(&sbi->s_lock);
 140                 ext2_sync_super(sb, es, 1);
 141         }
 142         db_count = sbi->s_gdb_count;
 143         for (i = 0; i < db_count; i++)
 144                 if (sbi->s_group_desc[i])
 145                         brelse (sbi->s_group_desc[i]);
 146         kfree(sbi->s_group_desc);
 147         kfree(sbi->s_debts);
 148         percpu_counter_destroy(&sbi->s_freeblocks_counter);
 149         percpu_counter_destroy(&sbi->s_freeinodes_counter);
 150         percpu_counter_destroy(&sbi->s_dirs_counter);
 151         brelse (sbi->s_sbh);
 152         sb->s_fs_info = NULL;
 153         kfree(sbi->s_blockgroup_lock);
 154         kfree(sbi);
 155 }
 156
 157 static struct kmem_cache * ext2_inode_cachep;
 158
 159 static struct inode *ext2_alloc_inode(struct super_block *sb)
 160 {
 161         struct ext2_inode_info *ei;
 162         ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
 163         if (!ei)
 164                 return NULL;
 165         ei->i_block_alloc_info = NULL;
 166         ei->vfs_inode.i_version = 1;
 167         return &ei->vfs_inode;
 168 }
 169
 170 static void ext2_i_callback(struct rcu_head *head)
 171 {
 172         struct inode *inode = container_of(head, struct inode, i_rcu);
 173         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
 174 }
 175
 176 static void ext2_destroy_inode(struct inode *inode)
 177 {
 178         call_rcu(&inode->i_rcu, ext2_i_callback);
 179 }
 180
 181 static void init_once(void *foo)
 182 {
 183         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
 184
 185         rwlock_init(&ei->i_meta_lock);
 186 #ifdef CONFIG_EXT2_FS_XATTR
 187         init_rwsem(&ei->xattr_sem);
 188 #endif
 189         mutex_init(&ei->truncate_mutex);
 190         inode_init_once(&ei->vfs_inode);
 191 }
 192
 193 static int init_inodecache(void)
 194 {
 195         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
 196                                              sizeof(struct ext2_inode_info),
 197                                              0, (SLAB_RECLAIM_ACCOUNT|
 198                                                 SLAB_MEM_SPREAD),
 199                                              init_once);
 200         if (ext2_inode_cachep == NULL)
 201                 return -ENOMEM;
 202         return 0;
 203 }
 204
 205 static void destroy_inodecache(void)
 206 {
 207         kmem_cache_destroy(ext2_inode_cachep);
 208 }
 209
 210 static int ext2_show_options(struct seq_file *seq, struct dentry *root)
 211 {
 212         struct super_block *sb = root->d_sb;
 213         struct ext2_sb_info *sbi = EXT2_SB(sb);
 214         struct ext2_super_block *es = sbi->s_es;
 215         unsigned long def_mount_opts;
 216
 217         spin_lock(&sbi->s_lock);
 218         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 219
 220         if (sbi->s_sb_block != 1)
 221                 seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
 222         if (test_opt(sb, MINIX_DF))
 223                 seq_puts(seq, ",minixdf");
 224         if (test_opt(sb, GRPID))
 225                 seq_puts(seq, ",grpid");
 226         if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
 227                 seq_puts(seq, ",nogrpid");
 228         if (!uid_eq(sbi->s_resuid, make_kuid(&init_user_ns, EXT2_DEF_RESUID)) ||
 229             le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
 230                 seq_printf(seq, ",resuid=%u",
 231                                 from_kuid_munged(&init_user_ns, sbi->s_resuid));
 232         }
 233         if (!gid_eq(sbi->s_resgid, make_kgid(&init_user_ns, EXT2_DEF_RESGID)) ||
 234             le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
 235                 seq_printf(seq, ",resgid=%u",
 236                                 from_kgid_munged(&init_user_ns, sbi->s_resgid));
 237         }
 238         if (test_opt(sb, ERRORS_RO)) {
 239                 int def_errors = le16_to_cpu(es->s_errors);
 240
 241                 if (def_errors == EXT2_ERRORS_PANIC ||
 242                     def_errors == EXT2_ERRORS_CONTINUE) {
 243                         seq_puts(seq, ",errors=remount-ro");
 244                 }
 245         }
 246         if (test_opt(sb, ERRORS_CONT))
 247                 seq_puts(seq, ",errors=continue");
 248         if (test_opt(sb, ERRORS_PANIC))
 249                 seq_puts(seq, ",errors=panic");
 250         if (test_opt(sb, NO_UID32))
 251                 seq_puts(seq, ",nouid32");
 252         if (test_opt(sb, DEBUG))
 253                 seq_puts(seq, ",debug");
 254         if (test_opt(sb, OLDALLOC))
 255                 seq_puts(seq, ",oldalloc");
 256
 257 #ifdef CONFIG_EXT2_FS_XATTR
 258         if (test_opt(sb, XATTR_USER))
 259                 seq_puts(seq, ",user_xattr");
 260         if (!test_opt(sb, XATTR_USER) &&
 261             (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
 262                 seq_puts(seq, ",nouser_xattr");
 263         }
 264 #endif
 265
 266 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 267         if (test_opt(sb, POSIX_ACL))
 268                 seq_puts(seq, ",acl");
 269         if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
 270                 seq_puts(seq, ",noacl");
 271 #endif
 272
 273         if (test_opt(sb, NOBH))
 274                 seq_puts(seq, ",nobh");
 275
 276 #if defined(CONFIG_QUOTA)
 277         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
 278                 seq_puts(seq, ",usrquota");
 279
 280         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
 281                 seq_puts(seq, ",grpquota");
 282 #endif
 283
 284 #if defined(CONFIG_EXT2_FS_XIP)
 285         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
 286                 seq_puts(seq, ",xip");
 287 #endif
 288
 289         if (!test_opt(sb, RESERVATION))
 290                 seq_puts(seq, ",noreservation");
 291
 292         spin_unlock(&sbi->s_lock);
 293         return 0;
 294 }
 295
 296 #ifdef CONFIG_QUOTA
 297 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
 298 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
 299 #endif
 300
 301 static const struct super_operations ext2_sops = {
 302         .alloc_inode    = ext2_alloc_inode,
 303         .destroy_inode  = ext2_destroy_inode,
 304         .write_inode    = ext2_write_inode,
 305         .evict_inode    = ext2_evict_inode,
 306         .put_super      = ext2_put_super,
 307         .sync_fs        = ext2_sync_fs,
 308         .statfs         = ext2_statfs,
 309         .remount_fs     = ext2_remount,
 310         .show_options   = ext2_show_options,
 311 #ifdef CONFIG_QUOTA
 312         .quota_read     = ext2_quota_read,
 313         .quota_write    = ext2_quota_write,
 314 #endif
 315 };
 316
 317 static struct inode *ext2_nfs_get_inode(struct super_block *sb,
 318                 u64 ino, u32 generation)
 319 {
 320         struct inode *inode;
 321
 322         if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
 323                 return ERR_PTR(-ESTALE);
 324         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
 325                 return ERR_PTR(-ESTALE);
 326
 327         /*
 328          * ext2_iget isn't quite right if the inode is currently unallocated!
 329          * However ext2_iget currently does appropriate checks to handle stale
 330          * inodes so everything is OK.
 331          */
 332         inode = ext2_iget(sb, ino);
 333         if (IS_ERR(inode))
 334                 return ERR_CAST(inode);
 335         if (generation && inode->i_generation != generation) {
 336                 /* we didn't find the right inode.. */
 337                 iput(inode);
 338                 return ERR_PTR(-ESTALE);
 339         }
 340         return inode;
 341 }
 342
 343 static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 344                 int fh_len, int fh_type)
 345 {
 346         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 347                                     ext2_nfs_get_inode);
 348 }
 349
 350 static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
 351                 int fh_len, int fh_type)
 352 {
 353         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 354                                     ext2_nfs_get_inode);
 355 }
 356
 357 static const struct export_operations ext2_export_ops = {
 358         .fh_to_dentry = ext2_fh_to_dentry,
 359         .fh_to_parent = ext2_fh_to_parent,
 360         .get_parent = ext2_get_parent,
 361 };
 362
 363 static unsigned long get_sb_block(void **data)
 364 {
 365         unsigned long   sb_block;
 366         char            *options = (char *) *data;
 367
 368         if (!options || strncmp(options, "sb=", 3) != 0)
 369                 return 1;       /* Default location */
 370         options += 3;
 371         sb_block = simple_strtoul(options, &options, 0);
 372         if (*options && *options != ',') {
 373                 printk("EXT2-fs: Invalid sb specification: %s\n",
 374                        (char *) *data);
 375                 return 1;
 376         }
 377         if (*options == ',')
 378                 options++;
 379         *data = (void *) options;
 380         return sb_block;
 381 }
 382
 383 enum {
 384         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
 385         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
 386         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
 387         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
 388         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
 389         Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
 390 };
 391
 392 static const match_table_t tokens = {
 393         {Opt_bsd_df, "bsddf"},
 394         {Opt_minix_df, "minixdf"},
 395         {Opt_grpid, "grpid"},
 396         {Opt_grpid, "bsdgroups"},
 397         {Opt_nogrpid, "nogrpid"},
 398         {Opt_nogrpid, "sysvgroups"},
 399         {Opt_resgid, "resgid=%u"},
 400         {Opt_resuid, "resuid=%u"},
 401         {Opt_sb, "sb=%u"},
 402         {Opt_err_cont, "errors=continue"},
 403         {Opt_err_panic, "errors=panic"},
 404         {Opt_err_ro, "errors=remount-ro"},
 405         {Opt_nouid32, "nouid32"},
 406         {Opt_nocheck, "check=none"},
 407         {Opt_nocheck, "nocheck"},
 408         {Opt_debug, "debug"},
 409         {Opt_oldalloc, "oldalloc"},
 410         {Opt_orlov, "orlov"},
 411         {Opt_nobh, "nobh"},
 412         {Opt_user_xattr, "user_xattr"},
 413         {Opt_nouser_xattr, "nouser_xattr"},
 414         {Opt_acl, "acl"},
 415         {Opt_noacl, "noacl"},
 416         {Opt_xip, "xip"},
 417         {Opt_grpquota, "grpquota"},
 418         {Opt_ignore, "noquota"},
 419         {Opt_quota, "quota"},
 420         {Opt_usrquota, "usrquota"},
 421         {Opt_reservation, "reservation"},
 422         {Opt_noreservation, "noreservation"},
 423         {Opt_err, NULL}
 424 };
 425
 426 static int parse_options(char *options, struct super_block *sb)
 427 {
 428         char *p;
 429         struct ext2_sb_info *sbi = EXT2_SB(sb);
 430         substring_t args[MAX_OPT_ARGS];
 431         int option;
 432         kuid_t uid;
 433         kgid_t gid;
 434
 435         if (!options)
 436                 return 1;
 437
 438         while ((p = strsep (&options, ",")) != NULL) {
 439                 int token;
 440                 if (!*p)
 441                         continue;
 442
 443                 token = match_token(p, tokens, args);
 444                 switch (token) {
 445                 case Opt_bsd_df:
 446                         clear_opt (sbi->s_mount_opt, MINIX_DF);
 447                         break;
 448                 case Opt_minix_df:
 449                         set_opt (sbi->s_mount_opt, MINIX_DF);
 450                         break;
 451                 case Opt_grpid:
 452                         set_opt (sbi->s_mount_opt, GRPID);
 453                         break;
 454                 case Opt_nogrpid:
 455                         clear_opt (sbi->s_mount_opt, GRPID);
 456                         break;
 457                 case Opt_resuid:
 458                         if (match_int(&args[0], &option))
 459                                 return 0;
 460                         uid = make_kuid(current_user_ns(), option);
 461                         if (!uid_valid(uid)) {
 462                                 ext2_msg(sb, KERN_ERR, "Invalid uid value %d", option);
 463                                 return -1;
 464
 465                         }
 466                         sbi->s_resuid = uid;
 467                         break;
 468                 case Opt_resgid:
 469                         if (match_int(&args[0], &option))
 470                                 return 0;
 471                         gid = make_kgid(current_user_ns(), option);
 472                         if (!gid_valid(gid)) {
 473                                 ext2_msg(sb, KERN_ERR, "Invalid gid value %d", option);
 474                                 return -1;
 475                         }
 476                         sbi->s_resgid = gid;
 477                         break;
 478                 case Opt_sb:
 479                         /* handled by get_sb_block() instead of here */
 480                         /* *sb_block = match_int(&args[0]); */
 481                         break;
 482                 case Opt_err_panic:
 483                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 484                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
 485                         set_opt (sbi->s_mount_opt, ERRORS_PANIC);
 486                         break;
 487                 case Opt_err_ro:
 488                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 489                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 490                         set_opt (sbi->s_mount_opt, ERRORS_RO);
 491                         break;
 492                 case Opt_err_cont:
 493                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
 494                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 495                         set_opt (sbi->s_mount_opt, ERRORS_CONT);
 496                         break;
 497                 case Opt_nouid32:
 498                         set_opt (sbi->s_mount_opt, NO_UID32);
 499                         break;
 500                 case Opt_nocheck:
 501                         clear_opt (sbi->s_mount_opt, CHECK);
 502                         break;
 503                 case Opt_debug:
 504                         set_opt (sbi->s_mount_opt, DEBUG);
 505                         break;
 506                 case Opt_oldalloc:
 507                         set_opt (sbi->s_mount_opt, OLDALLOC);
 508                         break;
 509                 case Opt_orlov:
 510                         clear_opt (sbi->s_mount_opt, OLDALLOC);
 511                         break;
 512                 case Opt_nobh:
 513                         set_opt (sbi->s_mount_opt, NOBH);
 514                         break;
 515 #ifdef CONFIG_EXT2_FS_XATTR
 516                 case Opt_user_xattr:
 517                         set_opt (sbi->s_mount_opt, XATTR_USER);
 518                         break;
 519                 case Opt_nouser_xattr:
 520                         clear_opt (sbi->s_mount_opt, XATTR_USER);
 521                         break;
 522 #else
 523                 case Opt_user_xattr:
 524                 case Opt_nouser_xattr:
 525                         ext2_msg(sb, KERN_INFO, "(no)user_xattr options"
 526                                 "not supported");
 527                         break;
 528 #endif
 529 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 530                 case Opt_acl:
 531                         set_opt(sbi->s_mount_opt, POSIX_ACL);
 532                         break;
 533                 case Opt_noacl:
 534                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
 535                         break;
 536 #else
 537                 case Opt_acl:
 538                 case Opt_noacl:
 539                         ext2_msg(sb, KERN_INFO,
 540                                 "(no)acl options not supported");
 541                         break;
 542 #endif
 543                 case Opt_xip:
 544 #ifdef CONFIG_EXT2_FS_XIP
 545                         set_opt (sbi->s_mount_opt, XIP);
 546 #else
 547                         ext2_msg(sb, KERN_INFO, "xip option not supported");
 548 #endif
 549                         break;
 550
 551 #if defined(CONFIG_QUOTA)
 552                 case Opt_quota:
 553                 case Opt_usrquota:
 554                         set_opt(sbi->s_mount_opt, USRQUOTA);
 555                         break;
 556
 557                 case Opt_grpquota:
 558                         set_opt(sbi->s_mount_opt, GRPQUOTA);
 559                         break;
 560 #else
 561                 case Opt_quota:
 562                 case Opt_usrquota:
 563                 case Opt_grpquota:
 564                         ext2_msg(sb, KERN_INFO,
 565                                 "quota operations not supported");
 566                         break;
 567 #endif
 568
 569                 case Opt_reservation:
 570                         set_opt(sbi->s_mount_opt, RESERVATION);
 571                         ext2_msg(sb, KERN_INFO, "reservations ON");
 572                         break;
 573                 case Opt_noreservation:
 574                         clear_opt(sbi->s_mount_opt, RESERVATION);
 575                         ext2_msg(sb, KERN_INFO, "reservations OFF");
 576                         break;
 577                 case Opt_ignore:
 578                         break;
 579                 default:
 580                         return 0;
 581                 }
 582         }
 583         return 1;
 584 }
 585
 586 static int ext2_setup_super (struct super_block * sb,
 587                               struct ext2_super_block * es,
 588                               int read_only)
 589 {
 590         int res = 0;
 591         struct ext2_sb_info *sbi = EXT2_SB(sb);
 592
 593         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 594                 ext2_msg(sb, KERN_ERR,
 595                         "error: revision level too high, "
 596                         "forcing read-only mode");
 597                 res = MS_RDONLY;
 598         }
 599         if (read_only)
 600                 return res;
 601         if (!(sbi->s_mount_state & EXT2_VALID_FS))
 602                 ext2_msg(sb, KERN_WARNING,
 603                         "warning: mounting unchecked fs, "
 604                         "running e2fsck is recommended");
 605         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 606                 ext2_msg(sb, KERN_WARNING,
 607                         "warning: mounting fs with errors, "
 608                         "running e2fsck is recommended");
 609         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 610                  le16_to_cpu(es->s_mnt_count) >=
 611                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 612                 ext2_msg(sb, KERN_WARNING,
 613                         "warning: maximal mount count reached, "
 614                         "running e2fsck is recommended");
 615         else if (le32_to_cpu(es->s_checkinterval) &&
 616                 (le32_to_cpu(es->s_lastcheck) +
 617                         le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 618                 ext2_msg(sb, KERN_WARNING,
 619                         "warning: checktime reached, "
 620                         "running e2fsck is recommended");
 621         if (!le16_to_cpu(es->s_max_mnt_count))
 622                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 623         le16_add_cpu(&es->s_mnt_count, 1);
 624         if (test_opt (sb, DEBUG))
 625                 ext2_msg(sb, KERN_INFO, "%s, %s, bs=%lu, fs=%lu, gc=%lu, "
 626                         "bpg=%lu, ipg=%lu, mo=%04lx]",
 627                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 628                         sbi->s_frag_size,
 629                         sbi->s_groups_count,
 630                         EXT2_BLOCKS_PER_GROUP(sb),
 631                         EXT2_INODES_PER_GROUP(sb),
 632                         sbi->s_mount_opt);
 633         return res;
 634 }
 635
 636 static int ext2_check_descriptors(struct super_block *sb)
 637 {
 638         int i;
 639         struct ext2_sb_info *sbi = EXT2_SB(sb);
 640
 641         ext2_debug ("Checking group descriptors");
 642
 643         for (i = 0; i < sbi->s_groups_count; i++) {
 644                 struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
 645                 ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
 646                 ext2_fsblk_t last_block;
 647
 648                 if (i == sbi->s_groups_count - 1)
 649                         last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
 650                 else
 651                         last_block = first_block +
 652                                 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
 653
 654                 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
 655                     le32_to_cpu(gdp->bg_block_bitmap) > last_block)
 656                 {
 657                         ext2_error (sb, "ext2_check_descriptors",
 658                                     "Block bitmap for group %d"
 659                                     " not in group (block %lu)!",
 660                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 661                         return 0;
 662                 }
 663                 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
 664                     le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
 665                 {
 666                         ext2_error (sb, "ext2_check_descriptors",
 667                                     "Inode bitmap for group %d"
 668                                     " not in group (block %lu)!",
 669                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 670                         return 0;
 671                 }
 672                 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
 673                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
 674                     last_block)
 675                 {
 676                         ext2_error (sb, "ext2_check_descriptors",
 677                                     "Inode table for group %d"
 678                                     " not in group (block %lu)!",
 679                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 680                         return 0;
 681                 }
 682         }
 683         return 1;
 684 }
 685
 686 /*
 687  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 688  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 689  * We need to be 1 filesystem block less than the 2^32 sector limit.
 690  */
 691 static loff_t ext2_max_size(int bits)
 692 {
 693         loff_t res = EXT2_NDIR_BLOCKS;
 694         int meta_blocks;
 695         loff_t upper_limit;
 696
 697         /* This is calculated to be the largest file size for a
 698          * dense, file such that the total number of
 699          * sectors in the file, including data and all indirect blocks,
 700          * does not exceed 2^32 -1
 701          * __u32 i_blocks representing the total number of
 702          * 512 bytes blocks of the file
 703          */
 704         upper_limit = (1LL << 32) - 1;
 705
 706         /* total blocks in file system block size */
 707         upper_limit >>= (bits - 9);
 708
 709
 710         /* indirect blocks */
 711         meta_blocks = 1;
 712         /* double indirect blocks */
 713         meta_blocks += 1 + (1LL << (bits-2));
 714         /* tripple indirect blocks */
 715         meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
 716
 717         upper_limit -= meta_blocks;
 718         upper_limit <<= bits;
 719
 720         res += 1LL << (bits-2);
 721         res += 1LL << (2*(bits-2));
 722         res += 1LL << (3*(bits-2));
 723         res <<= bits;
 724         if (res > upper_limit)
 725                 res = upper_limit;
 726
 727         if (res > MAX_LFS_FILESIZE)
 728                 res = MAX_LFS_FILESIZE;
 729
 730         return res;
 731 }
 732
 733 static unsigned long descriptor_loc(struct super_block *sb,
 734                                     unsigned long logic_sb_block,
 735                                     int nr)
 736 {
 737         struct ext2_sb_info *sbi = EXT2_SB(sb);
 738         unsigned long bg, first_meta_bg;
 739         int has_super = 0;
 740
 741         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 742
 743         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 744             nr < first_meta_bg)
 745                 return (logic_sb_block + nr + 1);
 746         bg = sbi->s_desc_per_block * nr;
 747         if (ext2_bg_has_super(sb, bg))
 748                 has_super = 1;
 749
 750         return ext2_group_first_block_no(sb, bg) + has_super;
 751 }
 752
 753 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 754 {
 755         struct buffer_head * bh;
 756         struct ext2_sb_info * sbi;
 757         struct ext2_super_block * es;
 758         struct inode *root;
 759         unsigned long block;
 760         unsigned long sb_block = get_sb_block(&data);
 761         unsigned long logic_sb_block;
 762         unsigned long offset = 0;
 763         unsigned long def_mount_opts;
 764         long ret = -EINVAL;
 765         int blocksize = BLOCK_SIZE;
 766         int db_count;
 767         int i, j;
 768         __le32 features;
 769         int err;
 770
 771         err = -ENOMEM;
 772         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 773         if (!sbi)
 774                 goto failed_unlock;
 775
 776         sbi->s_blockgroup_lock =
 777                 kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
 778         if (!sbi->s_blockgroup_lock) {
 779                 kfree(sbi);
 780                 goto failed_unlock;
 781         }
 782         sb->s_fs_info = sbi;
 783         sbi->s_sb_block = sb_block;
 784
 785         spin_lock_init(&sbi->s_lock);
 786
 787         /*
 788          * See what the current blocksize for the device is, and
 789          * use that as the blocksize.  Otherwise (or if the blocksize
 790          * is smaller than the default) use the default.
 791          * This is important for devices that have a hardware
 792          * sectorsize that is larger than the default.
 793          */
 794         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 795         if (!blocksize) {
 796                 ext2_msg(sb, KERN_ERR, "error: unable to set blocksize");
 797                 goto failed_sbi;
 798         }
 799
 800         /*
 801          * If the superblock doesn't start on a hardware sector boundary,
 802          * calculate the offset.
 803          */
 804         if (blocksize != BLOCK_SIZE) {
 805                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 806                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 807         } else {
 808                 logic_sb_block = sb_block;
 809         }
 810
 811         if (!(bh = sb_bread(sb, logic_sb_block))) {
 812                 ext2_msg(sb, KERN_ERR, "error: unable to read superblock");
 813                 goto failed_sbi;
 814         }
 815         /*
 816          * Note: s_es must be initialized as soon as possible because
 817          *       some ext2 macro-instructions depend on its value
 818          */
 819         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 820         sbi->s_es = es;
 821         sb->s_magic = le16_to_cpu(es->s_magic);
 822
 823         if (sb->s_magic != EXT2_SUPER_MAGIC)
 824                 goto cantfind_ext2;
 825
 826         /* Set defaults before we parse the mount options */
 827         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 828         if (def_mount_opts & EXT2_DEFM_DEBUG)
 829                 set_opt(sbi->s_mount_opt, DEBUG);
 830         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 831                 set_opt(sbi->s_mount_opt, GRPID);
 832         if (def_mount_opts & EXT2_DEFM_UID16)
 833                 set_opt(sbi->s_mount_opt, NO_UID32);
 834 #ifdef CONFIG_EXT2_FS_XATTR
 835         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 836                 set_opt(sbi->s_mount_opt, XATTR_USER);
 837 #endif
 838 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 839         if (def_mount_opts & EXT2_DEFM_ACL)
 840                 set_opt(sbi->s_mount_opt, POSIX_ACL);
 841 #endif
 842
 843         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 844                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 845         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
 846                 set_opt(sbi->s_mount_opt, ERRORS_CONT);
 847         else
 848                 set_opt(sbi->s_mount_opt, ERRORS_RO);
 849
 850         sbi->s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
 851         sbi->s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
 852
 853         set_opt(sbi->s_mount_opt, RESERVATION);
 854
 855         if (!parse_options((char *) data, sb))
 856                 goto failed_mount;
 857
 858         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 859                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 860                  MS_POSIXACL : 0);
 861
 862         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
 863                                     EXT2_MOUNT_XIP if not */
 864
 865         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 866             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 867              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 868              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 869                 ext2_msg(sb, KERN_WARNING,
 870                         "warning: feature flags set on rev 0 fs, "
 871                         "running e2fsck is recommended");
 872         /*
 873          * Check feature flags regardless of the revision level, since we
 874          * previously didn't change the revision level when setting the flags,
 875          * so there is a chance incompat flags are set on a rev 0 filesystem.
 876          */
 877         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 878         if (features) {
 879                 ext2_msg(sb, KERN_ERR,  "error: couldn't mount because of "
 880                        "unsupported optional features (%x)",
 881                         le32_to_cpu(features));
 882                 goto failed_mount;
 883         }
 884         if (!(sb->s_flags & MS_RDONLY) &&
 885             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 886                 ext2_msg(sb, KERN_ERR, "error: couldn't mount RDWR because of "
 887                        "unsupported optional features (%x)",
 888                        le32_to_cpu(features));
 889                 goto failed_mount;
 890         }
 891
 892         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 893
 894         if (ext2_use_xip(sb) && blocksize != PAGE_SIZE) {
 895                 if (!silent)
 896                         ext2_msg(sb, KERN_ERR,
 897                                 "error: unsupported blocksize for xip");
 898                 goto failed_mount;
 899         }
 900
 901         /* If the blocksize doesn't match, re-read the thing.. */
 902         if (sb->s_blocksize != blocksize) {
 903                 brelse(bh);
 904
 905                 if (!sb_set_blocksize(sb, blocksize)) {
 906                         ext2_msg(sb, KERN_ERR,
 907                                 "error: bad blocksize %d", blocksize);
 908                         goto failed_sbi;
 909                 }
 910
 911                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 912                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 913                 bh = sb_bread(sb, logic_sb_block);
 914                 if(!bh) {
 915                         ext2_msg(sb, KERN_ERR, "error: couldn't read"
 916                                 "superblock on 2nd try");
 917                         goto failed_sbi;
 918                 }
 919                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 920                 sbi->s_es = es;
 921                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 922                         ext2_msg(sb, KERN_ERR, "error: magic mismatch");
 923                         goto failed_mount;
 924                 }
 925         }
 926
 927         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 928         sb->s_max_links = EXT2_LINK_MAX;
 929
 930         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 931                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 932                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 933         } else {
 934                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 935                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 936                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 937                     !is_power_of_2(sbi->s_inode_size) ||
 938                     (sbi->s_inode_size > blocksize)) {
 939                         ext2_msg(sb, KERN_ERR,
 940                                 "error: unsupported inode size: %d",
 941                                 sbi->s_inode_size);
 942                         goto failed_mount;
 943                 }
 944         }
 945
 946         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 947                                    le32_to_cpu(es->s_log_frag_size);
 948         if (sbi->s_frag_size == 0)
 949                 goto cantfind_ext2;
 950         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
 951
 952         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 953         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 954         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 955
 956         if (EXT2_INODE_SIZE(sb) == 0)
 957                 goto cantfind_ext2;
 958         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
 959         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
 960                 goto cantfind_ext2;
 961         sbi->s_itb_per_group = sbi->s_inodes_per_group /
 962                                         sbi->s_inodes_per_block;
 963         sbi->s_desc_per_block = sb->s_blocksize /
 964                                         sizeof (struct ext2_group_desc);
 965         sbi->s_sbh = bh;
 966         sbi->s_mount_state = le16_to_cpu(es->s_state);
 967         sbi->s_addr_per_block_bits =
 968                 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
 969         sbi->s_desc_per_block_bits =
 970                 ilog2 (EXT2_DESC_PER_BLOCK(sb));
 971
 972         if (sb->s_magic != EXT2_SUPER_MAGIC)
 973                 goto cantfind_ext2;
 974
 975         if (sb->s_blocksize != bh->b_size) {
 976                 if (!silent)
 977                         ext2_msg(sb, KERN_ERR, "error: unsupported blocksize");
 978                 goto failed_mount;
 979         }
 980
 981         if (sb->s_blocksize != sbi->s_frag_size) {
 982                 ext2_msg(sb, KERN_ERR,
 983                         "error: fragsize %lu != blocksize %lu"
 984                         "(not supported yet)",
 985                         sbi->s_frag_size, sb->s_blocksize);
 986                 goto failed_mount;
 987         }
 988
 989         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
 990                 ext2_msg(sb, KERN_ERR,
 991                         "error: #blocks per group too big: %lu",
 992                         sbi->s_blocks_per_group);
 993                 goto failed_mount;
 994         }
 995         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 996                 ext2_msg(sb, KERN_ERR,
 997                         "error: #fragments per group too big: %lu",
 998                         sbi->s_frags_per_group);
 999                 goto failed_mount;
1000         }
1001         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
1002                 ext2_msg(sb, KERN_ERR,
1003                         "error: #inodes per group too big: %lu",
1004                         sbi->s_inodes_per_group);
1005                 goto failed_mount;
1006         }
1007
1008         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
1009                 goto cantfind_ext2;
1010         sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
1011                                 le32_to_cpu(es->s_first_data_block) - 1)
1012                                         / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
1013         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
1014                    EXT2_DESC_PER_BLOCK(sb);
1015         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
1016         if (sbi->s_group_desc == NULL) {
1017                 ext2_msg(sb, KERN_ERR, "error: not enough memory");
1018                 goto failed_mount;
1019         }
1020         bgl_lock_init(sbi->s_blockgroup_lock);
1021         sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
1022         if (!sbi->s_debts) {
1023                 ext2_msg(sb, KERN_ERR, "error: not enough memory");
1024                 goto failed_mount_group_desc;
1025         }
1026         for (i = 0; i < db_count; i++) {
1027                 block = descriptor_loc(sb, logic_sb_block, i);
1028                 sbi->s_group_desc[i] = sb_bread(sb, block);
1029                 if (!sbi->s_group_desc[i]) {
1030                         for (j = 0; j < i; j++)
1031                                 brelse (sbi->s_group_desc[j]);
1032                         ext2_msg(sb, KERN_ERR,
1033                                 "error: unable to read group descriptors");
1034                         goto failed_mount_group_desc;
1035                 }
1036         }
1037         if (!ext2_check_descriptors (sb)) {
1038                 ext2_msg(sb, KERN_ERR, "group descriptors corrupted");
1039                 goto failed_mount2;
1040         }
1041         sbi->s_gdb_count = db_count;
1042         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1043         spin_lock_init(&sbi->s_next_gen_lock);
1044
1045         /* per fileystem reservation list head & lock */
1046         spin_lock_init(&sbi->s_rsv_window_lock);
1047         sbi->s_rsv_window_root = RB_ROOT;
1048         /*
1049          * Add a single, static dummy reservation to the start of the
1050          * reservation window list --- it gives us a placeholder for
1051          * append-at-start-of-list which makes the allocation logic
1052          * _much_ simpler.
1053          */
1054         sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1055         sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1056         sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1057         sbi->s_rsv_window_head.rsv_goal_size = 0;
1058         ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1059
1060         err = percpu_counter_init(&sbi->s_freeblocks_counter,
1061                                 ext2_count_free_blocks(sb));
1062         if (!err) {
1063                 err = percpu_counter_init(&sbi->s_freeinodes_counter,
1064                                 ext2_count_free_inodes(sb));
1065         }
1066         if (!err) {
1067                 err = percpu_counter_init(&sbi->s_dirs_counter,
1068                                 ext2_count_dirs(sb));
1069         }
1070         if (err) {
1071                 ext2_msg(sb, KERN_ERR, "error: insufficient memory");
1072                 goto failed_mount3;
1073         }
1074         /*
1075          * set up enough so that it can read an inode
1076          */
1077         sb->s_op = &ext2_sops;
1078         sb->s_export_op = &ext2_export_ops;
1079         sb->s_xattr = ext2_xattr_handlers;
1080
1081 #ifdef CONFIG_QUOTA
1082         sb->dq_op = &dquot_operations;
1083         sb->s_qcop = &dquot_quotactl_ops;
1084 #endif
1085
1086         root = ext2_iget(sb, EXT2_ROOT_INO);
1087         if (IS_ERR(root)) {
1088                 ret = PTR_ERR(root);
1089                 goto failed_mount3;
1090         }
1091         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1092                 iput(root);
1093                 ext2_msg(sb, KERN_ERR, "error: corrupt root inode, run e2fsck");
1094                 goto failed_mount3;
1095         }
1096
1097         sb->s_root = d_make_root(root);
1098         if (!sb->s_root) {
1099                 ext2_msg(sb, KERN_ERR, "error: get root inode failed");
1100                 ret = -ENOMEM;
1101                 goto failed_mount3;
1102         }
1103         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1104                 ext2_msg(sb, KERN_WARNING,
1105                         "warning: mounting ext3 filesystem as ext2");
1106         if (ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY))
1107                 sb->s_flags |= MS_RDONLY;
1108         ext2_write_super(sb);
1109         return 0;
1110
1111 cantfind_ext2:
1112         if (!silent)
1113                 ext2_msg(sb, KERN_ERR,
1114                         "error: can't find an ext2 filesystem on dev %s.",
1115                         sb->s_id);
1116         goto failed_mount;
1117 failed_mount3:
1118         percpu_counter_destroy(&sbi->s_freeblocks_counter);
1119         percpu_counter_destroy(&sbi->s_freeinodes_counter);
1120         percpu_counter_destroy(&sbi->s_dirs_counter);
1121 failed_mount2:
1122         for (i = 0; i < db_count; i++)
1123                 brelse(sbi->s_group_desc[i]);
1124 failed_mount_group_desc:
1125         kfree(sbi->s_group_desc);
1126         kfree(sbi->s_debts);
1127 failed_mount:
1128         brelse(bh);
1129 failed_sbi:
1130         sb->s_fs_info = NULL;
1131         kfree(sbi->s_blockgroup_lock);
1132         kfree(sbi);
1133 failed_unlock:
1134         return ret;
1135 }
1136
1137 static void ext2_clear_super_error(struct super_block *sb)
1138 {
1139         struct buffer_head *sbh = EXT2_SB(sb)->s_sbh;
1140
1141         if (buffer_write_io_error(sbh)) {
1142                 /*
1143                  * Oh, dear.  A previous attempt to write the
1144                  * superblock failed.  This could happen because the
1145                  * USB device was yanked out.  Or it could happen to
1146                  * be a transient write error and maybe the block will
1147                  * be remapped.  Nothing we can do but to retry the
1148                  * write and hope for the best.
1149                  */
1150                 ext2_msg(sb, KERN_ERR,
1151                        "previous I/O error to superblock detected\n");
1152                 clear_buffer_write_io_error(sbh);
1153                 set_buffer_uptodate(sbh);
1154         }
1155 }
1156
1157 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
1158                             int wait)
1159 {
1160         ext2_clear_super_error(sb);
1161         spin_lock(&EXT2_SB(sb)->s_lock);
1162         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1163         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1164         es->s_wtime = cpu_to_le32(get_seconds());
1165         /* unlock before we do IO */
1166         spin_unlock(&EXT2_SB(sb)->s_lock);
1167         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1168         if (wait)
1169                 sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1170 }
1171
1172 /*
1173  * In the second extended file system, it is not necessary to
1174  * write the super block since we use a mapping of the
1175  * disk super block in a buffer.
1176  *
1177  * However, this function is still used to set the fs valid
1178  * flags to 0.  We need to set this flag to 0 since the fs
1179  * may have been checked while mounted and e2fsck may have
1180  * set s_state to EXT2_VALID_FS after some corrections.
1181  */
1182 static int ext2_sync_fs(struct super_block *sb, int wait)
1183 {
1184         struct ext2_sb_info *sbi = EXT2_SB(sb);
1185         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
1186
1187         spin_lock(&sbi->s_lock);
1188         if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1189                 ext2_debug("setting valid to 0\n");
1190                 es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1191         }
1192         spin_unlock(&sbi->s_lock);
1193         ext2_sync_super(sb, es, wait);
1194         return 0;
1195 }
1196
1197
1198 void ext2_write_super(struct super_block *sb)
1199 {
1200         if (!(sb->s_flags & MS_RDONLY))
1201                 ext2_sync_fs(sb, 1);
1202 }
1203
1204 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1205 {
1206         struct ext2_sb_info * sbi = EXT2_SB(sb);
1207         struct ext2_super_block * es;
1208         unsigned long old_mount_opt = sbi->s_mount_opt;
1209         struct ext2_mount_options old_opts;
1210         unsigned long old_sb_flags;
1211         int err;
1212
1213         spin_lock(&sbi->s_lock);
1214
1215         /* Store the old options */
1216         old_sb_flags = sb->s_flags;
1217         old_opts.s_mount_opt = sbi->s_mount_opt;
1218         old_opts.s_resuid = sbi->s_resuid;
1219         old_opts.s_resgid = sbi->s_resgid;
1220
1221         /*
1222          * Allow the "check" option to be passed as a remount option.
1223          */
1224         if (!parse_options(data, sb)) {
1225                 err = -EINVAL;
1226                 goto restore_opts;
1227         }
1228
1229         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1230                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1231
1232         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
1233                                     EXT2_MOUNT_XIP if not */
1234
1235         if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
1236                 ext2_msg(sb, KERN_WARNING,
1237                         "warning: unsupported blocksize for xip");
1238                 err = -EINVAL;
1239                 goto restore_opts;
1240         }
1241
1242         es = sbi->s_es;
1243         if ((sbi->s_mount_opt ^ old_mount_opt) & EXT2_MOUNT_XIP) {
1244                 ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
1245                          "xip flag with busy inodes while remounting");
1246                 sbi->s_mount_opt &= ~EXT2_MOUNT_XIP;
1247                 sbi->s_mount_opt |= old_mount_opt & EXT2_MOUNT_XIP;
1248         }
1249         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
1250                 spin_unlock(&sbi->s_lock);
1251                 return 0;
1252         }
1253         if (*flags & MS_RDONLY) {
1254                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1255                     !(sbi->s_mount_state & EXT2_VALID_FS)) {
1256                         spin_unlock(&sbi->s_lock);
1257                         return 0;
1258                 }
1259
1260                 /*
1261                  * OK, we are remounting a valid rw partition rdonly, so set
1262                  * the rdonly flag and then mark the partition as valid again.
1263                  */
1264                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1265                 es->s_mtime = cpu_to_le32(get_seconds());
1266                 spin_unlock(&sbi->s_lock);
1267
1268                 err = dquot_suspend(sb, -1);
1269                 if (err < 0) {
1270                         spin_lock(&sbi->s_lock);
1271                         goto restore_opts;
1272                 }
1273
1274                 ext2_sync_super(sb, es, 1);
1275         } else {
1276                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1277                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1278                 if (ret) {
1279                         ext2_msg(sb, KERN_WARNING,
1280                                 "warning: couldn't remount RDWR because of "
1281                                 "unsupported optional features (%x).",
1282                                 le32_to_cpu(ret));
1283                         err = -EROFS;
1284                         goto restore_opts;
1285                 }
1286                 /*
1287                  * Mounting a RDONLY partition read-write, so reread and
1288                  * store the current valid flag.  (It may have been changed
1289                  * by e2fsck since we originally mounted the partition.)
1290                  */
1291                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1292                 if (!ext2_setup_super (sb, es, 0))
1293                         sb->s_flags &= ~MS_RDONLY;
1294                 spin_unlock(&sbi->s_lock);
1295
1296                 ext2_write_super(sb);
1297
1298                 dquot_resume(sb, -1);
1299         }
1300
1301         return 0;
1302 restore_opts:
1303         sbi->s_mount_opt = old_opts.s_mount_opt;
1304         sbi->s_resuid = old_opts.s_resuid;
1305         sbi->s_resgid = old_opts.s_resgid;
1306         sb->s_flags = old_sb_flags;
1307         spin_unlock(&sbi->s_lock);
1308         return err;
1309 }
1310
1311 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1312 {
1313         struct super_block *sb = dentry->d_sb;
1314         struct ext2_sb_info *sbi = EXT2_SB(sb);
1315         struct ext2_super_block *es = sbi->s_es;
1316         u64 fsid;
1317
1318         spin_lock(&sbi->s_lock);
1319
1320         if (test_opt (sb, MINIX_DF))
1321                 sbi->s_overhead_last = 0;
1322         else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1323                 unsigned long i, overhead = 0;
1324                 smp_rmb();
1325
1326                 /*
1327                  * Compute the overhead (FS structures). This is constant
1328                  * for a given filesystem unless the number of block groups
1329                  * changes so we cache the previous value until it does.
1330                  */
1331
1332                 /*
1333                  * All of the blocks before first_data_block are
1334                  * overhead
1335                  */
1336                 overhead = le32_to_cpu(es->s_first_data_block);
1337
1338                 /*
1339                  * Add the overhead attributed to the superblock and
1340                  * block group descriptors.  If the sparse superblocks
1341                  * feature is turned on, then not all groups have this.
1342                  */
1343                 for (i = 0; i < sbi->s_groups_count; i++)
1344                         overhead += ext2_bg_has_super(sb, i) +
1345                                 ext2_bg_num_gdb(sb, i);
1346
1347                 /*
1348                  * Every block group has an inode bitmap, a block
1349                  * bitmap, and an inode table.
1350                  */
1351                 overhead += (sbi->s_groups_count *
1352                              (2 + sbi->s_itb_per_group));
1353                 sbi->s_overhead_last = overhead;
1354                 smp_wmb();
1355                 sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1356         }
1357
1358         buf->f_type = EXT2_SUPER_MAGIC;
1359         buf->f_bsize = sb->s_blocksize;
1360         buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1361         buf->f_bfree = ext2_count_free_blocks(sb);
1362         es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1363         buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1364         if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1365                 buf->f_bavail = 0;
1366         buf->f_files = le32_to_cpu(es->s_inodes_count);
1367         buf->f_ffree = ext2_count_free_inodes(sb);
1368         es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1369         buf->f_namelen = EXT2_NAME_LEN;
1370         fsid = le64_to_cpup((void *)es->s_uuid) ^
1371                le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1372         buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1373         buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1374         spin_unlock(&sbi->s_lock);
1375         return 0;
1376 }
1377
1378 static struct dentry *ext2_mount(struct file_system_type *fs_type,
1379         int flags, const char *dev_name, void *data)
1380 {
1381         return mount_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1382 }
1383
1384 #ifdef CONFIG_QUOTA
1385
1386 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1387  * acquiring the locks... As quota files are never truncated and quota code
1388  * itself serializes the operations (and no one else should touch the files)
1389  * we don't have to be afraid of races */
1390 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1391                                size_t len, loff_t off)
1392 {
1393         struct inode *inode = sb_dqopt(sb)->files[type];
1394         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1395         int err = 0;
1396         int offset = off & (sb->s_blocksize - 1);
1397         int tocopy;
1398         size_t toread;
1399         struct buffer_head tmp_bh;
1400         struct buffer_head *bh;
1401         loff_t i_size = i_size_read(inode);
1402
1403         if (off > i_size)
1404                 return 0;
1405         if (off+len > i_size)
1406                 len = i_size-off;
1407         toread = len;
1408         while (toread > 0) {
1409                 tocopy = sb->s_blocksize - offset < toread ?
1410                                 sb->s_blocksize - offset : toread;
1411
1412                 tmp_bh.b_state = 0;
1413                 tmp_bh.b_size = sb->s_blocksize;
1414                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1415                 if (err < 0)
1416                         return err;
1417                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1418                         memset(data, 0, tocopy);
1419                 else {
1420                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1421                         if (!bh)
1422                                 return -EIO;
1423                         memcpy(data, bh->b_data+offset, tocopy);
1424                         brelse(bh);
1425                 }
1426                 offset = 0;
1427                 toread -= tocopy;
1428                 data += tocopy;
1429                 blk++;
1430         }
1431         return len;
1432 }
1433
1434 /* Write to quotafile */
1435 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1436                                 const char *data, size_t len, loff_t off)
1437 {
1438         struct inode *inode = sb_dqopt(sb)->files[type];
1439         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1440         int err = 0;
1441         int offset = off & (sb->s_blocksize - 1);
1442         int tocopy;
1443         size_t towrite = len;
1444         struct buffer_head tmp_bh;
1445         struct buffer_head *bh;
1446
1447         while (towrite > 0) {
1448                 tocopy = sb->s_blocksize - offset < towrite ?
1449                                 sb->s_blocksize - offset : towrite;
1450
1451                 tmp_bh.b_state = 0;
1452                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1453                 if (err < 0)
1454                         goto out;
1455                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1456                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1457                 else
1458                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1459                 if (!bh) {
1460                         err = -EIO;
1461                         goto out;
1462                 }
1463                 lock_buffer(bh);
1464                 memcpy(bh->b_data+offset, data, tocopy);
1465                 flush_dcache_page(bh->b_page);
1466                 set_buffer_uptodate(bh);
1467                 mark_buffer_dirty(bh);
1468                 unlock_buffer(bh);
1469                 brelse(bh);
1470                 offset = 0;
1471                 towrite -= tocopy;
1472                 data += tocopy;
1473                 blk++;
1474         }
1475 out:
1476         if (len == towrite)
1477                 return err;
1478         if (inode->i_size < off+len-towrite)
1479                 i_size_write(inode, off+len-towrite);
1480         inode->i_version++;
1481         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1482         mark_inode_dirty(inode);
1483         return len - towrite;
1484 }
1485
1486 #endif
1487
1488 static struct file_system_type ext2_fs_type = {
1489         .owner          = THIS_MODULE,
1490         .name           = "ext2",
1491         .mount          = ext2_mount,
1492         .kill_sb        = kill_block_super,
1493         .fs_flags       = FS_REQUIRES_DEV,
1494 };
1495
1496 static int __init init_ext2_fs(void)
1497 {
1498         int err = init_ext2_xattr();
1499         if (err)
1500                 return err;
1501         err = init_inodecache();
1502         if (err)
1503                 goto out1;
1504         err = register_filesystem(&ext2_fs_type);
1505         if (err)
1506                 goto out;
1507         return 0;
1508 out:
1509         destroy_inodecache();
1510 out1:
1511         exit_ext2_xattr();
1512         return err;
1513 }
1514
1515 static void __exit exit_ext2_fs(void)
1516 {
1517         unregister_filesystem(&ext2_fs_type);
1518         destroy_inodecache();
1519         exit_ext2_xattr();
1520 }
1521
1522 MODULE_AUTHOR("Remy Card and others");
1523 MODULE_DESCRIPTION("Second Extended Filesystem");
1524 MODULE_LICENSE("GPL");
1525 module_init(init_ext2_fs)
1526 module_exit(exit_ext2_fs)