linux/fs/ext2/super.c
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   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
  40static void ext2_sync_super(struct super_block *sb,
  41                            struct ext2_super_block *es, int wait);
  42static int ext2_remount (struct super_block * sb, int * flags, char * data);
  43static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
  44static int ext2_sync_fs(struct super_block *sb, int wait);
  45
  46void 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
  81void 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 */
 100void 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
 125static 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        if (sb->s_dirt)
 134                ext2_write_super(sb);
 135
 136        ext2_xattr_put_super(sb);
 137        if (!(sb->s_flags & MS_RDONLY)) {
 138                struct ext2_super_block *es = sbi->s_es;
 139
 140                spin_lock(&sbi->s_lock);
 141                es->s_state = cpu_to_le16(sbi->s_mount_state);
 142                spin_unlock(&sbi->s_lock);
 143                ext2_sync_super(sb, es, 1);
 144        }
 145        db_count = sbi->s_gdb_count;
 146        for (i = 0; i < db_count; i++)
 147                if (sbi->s_group_desc[i])
 148                        brelse (sbi->s_group_desc[i]);
 149        kfree(sbi->s_group_desc);
 150        kfree(sbi->s_debts);
 151        percpu_counter_destroy(&sbi->s_freeblocks_counter);
 152        percpu_counter_destroy(&sbi->s_freeinodes_counter);
 153        percpu_counter_destroy(&sbi->s_dirs_counter);
 154        brelse (sbi->s_sbh);
 155        sb->s_fs_info = NULL;
 156        kfree(sbi->s_blockgroup_lock);
 157        kfree(sbi);
 158}
 159
 160static struct kmem_cache * ext2_inode_cachep;
 161
 162static struct inode *ext2_alloc_inode(struct super_block *sb)
 163{
 164        struct ext2_inode_info *ei;
 165        ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
 166        if (!ei)
 167                return NULL;
 168        ei->i_block_alloc_info = NULL;
 169        ei->vfs_inode.i_version = 1;
 170        return &ei->vfs_inode;
 171}
 172
 173static void ext2_i_callback(struct rcu_head *head)
 174{
 175        struct inode *inode = container_of(head, struct inode, i_rcu);
 176        INIT_LIST_HEAD(&inode->i_dentry);
 177        kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
 178}
 179
 180static void ext2_destroy_inode(struct inode *inode)
 181{
 182        call_rcu(&inode->i_rcu, ext2_i_callback);
 183}
 184
 185static void init_once(void *foo)
 186{
 187        struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
 188
 189        rwlock_init(&ei->i_meta_lock);
 190#ifdef CONFIG_EXT2_FS_XATTR
 191        init_rwsem(&ei->xattr_sem);
 192#endif
 193        mutex_init(&ei->truncate_mutex);
 194        inode_init_once(&ei->vfs_inode);
 195}
 196
 197static int init_inodecache(void)
 198{
 199        ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
 200                                             sizeof(struct ext2_inode_info),
 201                                             0, (SLAB_RECLAIM_ACCOUNT|
 202                                                SLAB_MEM_SPREAD),
 203                                             init_once);
 204        if (ext2_inode_cachep == NULL)
 205                return -ENOMEM;
 206        return 0;
 207}
 208
 209static void destroy_inodecache(void)
 210{
 211        kmem_cache_destroy(ext2_inode_cachep);
 212}
 213
 214static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
 215{
 216        struct super_block *sb = vfs->mnt_sb;
 217        struct ext2_sb_info *sbi = EXT2_SB(sb);
 218        struct ext2_super_block *es = sbi->s_es;
 219        unsigned long def_mount_opts;
 220
 221        spin_lock(&sbi->s_lock);
 222        def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 223
 224        if (sbi->s_sb_block != 1)
 225                seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
 226        if (test_opt(sb, MINIX_DF))
 227                seq_puts(seq, ",minixdf");
 228        if (test_opt(sb, GRPID))
 229                seq_puts(seq, ",grpid");
 230        if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
 231                seq_puts(seq, ",nogrpid");
 232        if (sbi->s_resuid != EXT2_DEF_RESUID ||
 233            le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
 234                seq_printf(seq, ",resuid=%u", sbi->s_resuid);
 235        }
 236        if (sbi->s_resgid != EXT2_DEF_RESGID ||
 237            le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
 238                seq_printf(seq, ",resgid=%u", sbi->s_resgid);
 239        }
 240        if (test_opt(sb, ERRORS_RO)) {
 241                int def_errors = le16_to_cpu(es->s_errors);
 242
 243                if (def_errors == EXT2_ERRORS_PANIC ||
 244                    def_errors == EXT2_ERRORS_CONTINUE) {
 245                        seq_puts(seq, ",errors=remount-ro");
 246                }
 247        }
 248        if (test_opt(sb, ERRORS_CONT))
 249                seq_puts(seq, ",errors=continue");
 250        if (test_opt(sb, ERRORS_PANIC))
 251                seq_puts(seq, ",errors=panic");
 252        if (test_opt(sb, NO_UID32))
 253                seq_puts(seq, ",nouid32");
 254        if (test_opt(sb, DEBUG))
 255                seq_puts(seq, ",debug");
 256        if (test_opt(sb, OLDALLOC))
 257                seq_puts(seq, ",oldalloc");
 258
 259#ifdef CONFIG_EXT2_FS_XATTR
 260        if (test_opt(sb, XATTR_USER))
 261                seq_puts(seq, ",user_xattr");
 262        if (!test_opt(sb, XATTR_USER) &&
 263            (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
 264                seq_puts(seq, ",nouser_xattr");
 265        }
 266#endif
 267
 268#ifdef CONFIG_EXT2_FS_POSIX_ACL
 269        if (test_opt(sb, POSIX_ACL))
 270                seq_puts(seq, ",acl");
 271        if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
 272                seq_puts(seq, ",noacl");
 273#endif
 274
 275        if (test_opt(sb, NOBH))
 276                seq_puts(seq, ",nobh");
 277
 278#if defined(CONFIG_QUOTA)
 279        if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
 280                seq_puts(seq, ",usrquota");
 281
 282        if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
 283                seq_puts(seq, ",grpquota");
 284#endif
 285
 286#if defined(CONFIG_EXT2_FS_XIP)
 287        if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
 288                seq_puts(seq, ",xip");
 289#endif
 290
 291        if (!test_opt(sb, RESERVATION))
 292                seq_puts(seq, ",noreservation");
 293
 294        spin_unlock(&sbi->s_lock);
 295        return 0;
 296}
 297
 298#ifdef CONFIG_QUOTA
 299static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
 300static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
 301#endif
 302
 303static const struct super_operations ext2_sops = {
 304        .alloc_inode    = ext2_alloc_inode,
 305        .destroy_inode  = ext2_destroy_inode,
 306        .write_inode    = ext2_write_inode,
 307        .evict_inode    = ext2_evict_inode,
 308        .put_super      = ext2_put_super,
 309        .write_super    = ext2_write_super,
 310        .sync_fs        = ext2_sync_fs,
 311        .statfs         = ext2_statfs,
 312        .remount_fs     = ext2_remount,
 313        .show_options   = ext2_show_options,
 314#ifdef CONFIG_QUOTA
 315        .quota_read     = ext2_quota_read,
 316        .quota_write    = ext2_quota_write,
 317#endif
 318};
 319
 320static struct inode *ext2_nfs_get_inode(struct super_block *sb,
 321                u64 ino, u32 generation)
 322{
 323        struct inode *inode;
 324
 325        if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
 326                return ERR_PTR(-ESTALE);
 327        if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
 328                return ERR_PTR(-ESTALE);
 329
 330        /*
 331         * ext2_iget isn't quite right if the inode is currently unallocated!
 332         * However ext2_iget currently does appropriate checks to handle stale
 333         * inodes so everything is OK.
 334         */
 335        inode = ext2_iget(sb, ino);
 336        if (IS_ERR(inode))
 337                return ERR_CAST(inode);
 338        if (generation && inode->i_generation != generation) {
 339                /* we didn't find the right inode.. */
 340                iput(inode);
 341                return ERR_PTR(-ESTALE);
 342        }
 343        return inode;
 344}
 345
 346static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 347                int fh_len, int fh_type)
 348{
 349        return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 350                                    ext2_nfs_get_inode);
 351}
 352
 353static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
 354                int fh_len, int fh_type)
 355{
 356        return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 357                                    ext2_nfs_get_inode);
 358}
 359
 360/* Yes, most of these are left as NULL!!
 361 * A NULL value implies the default, which works with ext2-like file
 362 * systems, but can be improved upon.
 363 * Currently only get_parent is required.
 364 */
 365static const struct export_operations ext2_export_ops = {
 366        .fh_to_dentry = ext2_fh_to_dentry,
 367        .fh_to_parent = ext2_fh_to_parent,
 368        .get_parent = ext2_get_parent,
 369};
 370
 371static unsigned long get_sb_block(void **data)
 372{
 373        unsigned long   sb_block;
 374        char            *options = (char *) *data;
 375
 376        if (!options || strncmp(options, "sb=", 3) != 0)
 377                return 1;       /* Default location */
 378        options += 3;
 379        sb_block = simple_strtoul(options, &options, 0);
 380        if (*options && *options != ',') {
 381                printk("EXT2-fs: Invalid sb specification: %s\n",
 382                       (char *) *data);
 383                return 1;
 384        }
 385        if (*options == ',')
 386                options++;
 387        *data = (void *) options;
 388        return sb_block;
 389}
 390
 391enum {
 392        Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
 393        Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
 394        Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
 395        Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
 396        Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
 397        Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
 398};
 399
 400static const match_table_t tokens = {
 401        {Opt_bsd_df, "bsddf"},
 402        {Opt_minix_df, "minixdf"},
 403        {Opt_grpid, "grpid"},
 404        {Opt_grpid, "bsdgroups"},
 405        {Opt_nogrpid, "nogrpid"},
 406        {Opt_nogrpid, "sysvgroups"},
 407        {Opt_resgid, "resgid=%u"},
 408        {Opt_resuid, "resuid=%u"},
 409        {Opt_sb, "sb=%u"},
 410        {Opt_err_cont, "errors=continue"},
 411        {Opt_err_panic, "errors=panic"},
 412        {Opt_err_ro, "errors=remount-ro"},
 413        {Opt_nouid32, "nouid32"},
 414        {Opt_nocheck, "check=none"},
 415        {Opt_nocheck, "nocheck"},
 416        {Opt_debug, "debug"},
 417        {Opt_oldalloc, "oldalloc"},
 418        {Opt_orlov, "orlov"},
 419        {Opt_nobh, "nobh"},
 420        {Opt_user_xattr, "user_xattr"},
 421        {Opt_nouser_xattr, "nouser_xattr"},
 422        {Opt_acl, "acl"},
 423        {Opt_noacl, "noacl"},
 424        {Opt_xip, "xip"},
 425        {Opt_grpquota, "grpquota"},
 426        {Opt_ignore, "noquota"},
 427        {Opt_quota, "quota"},
 428        {Opt_usrquota, "usrquota"},
 429        {Opt_reservation, "reservation"},
 430        {Opt_noreservation, "noreservation"},
 431        {Opt_err, NULL}
 432};
 433
 434static int parse_options(char *options, struct super_block *sb)
 435{
 436        char *p;
 437        struct ext2_sb_info *sbi = EXT2_SB(sb);
 438        substring_t args[MAX_OPT_ARGS];
 439        int option;
 440
 441        if (!options)
 442                return 1;
 443
 444        while ((p = strsep (&options, ",")) != NULL) {
 445                int token;
 446                if (!*p)
 447                        continue;
 448
 449                token = match_token(p, tokens, args);
 450                switch (token) {
 451                case Opt_bsd_df:
 452                        clear_opt (sbi->s_mount_opt, MINIX_DF);
 453                        break;
 454                case Opt_minix_df:
 455                        set_opt (sbi->s_mount_opt, MINIX_DF);
 456                        break;
 457                case Opt_grpid:
 458                        set_opt (sbi->s_mount_opt, GRPID);
 459                        break;
 460                case Opt_nogrpid:
 461                        clear_opt (sbi->s_mount_opt, GRPID);
 462                        break;
 463                case Opt_resuid:
 464                        if (match_int(&args[0], &option))
 465                                return 0;
 466                        sbi->s_resuid = option;
 467                        break;
 468                case Opt_resgid:
 469                        if (match_int(&args[0], &option))
 470                                return 0;
 471                        sbi->s_resgid = option;
 472                        break;
 473                case Opt_sb:
 474                        /* handled by get_sb_block() instead of here */
 475                        /* *sb_block = match_int(&args[0]); */
 476                        break;
 477                case Opt_err_panic:
 478                        clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 479                        clear_opt (sbi->s_mount_opt, ERRORS_RO);
 480                        set_opt (sbi->s_mount_opt, ERRORS_PANIC);
 481                        break;
 482                case Opt_err_ro:
 483                        clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 484                        clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 485                        set_opt (sbi->s_mount_opt, ERRORS_RO);
 486                        break;
 487                case Opt_err_cont:
 488                        clear_opt (sbi->s_mount_opt, ERRORS_RO);
 489                        clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 490                        set_opt (sbi->s_mount_opt, ERRORS_CONT);
 491                        break;
 492                case Opt_nouid32:
 493                        set_opt (sbi->s_mount_opt, NO_UID32);
 494                        break;
 495                case Opt_nocheck:
 496                        clear_opt (sbi->s_mount_opt, CHECK);
 497                        break;
 498                case Opt_debug:
 499                        set_opt (sbi->s_mount_opt, DEBUG);
 500                        break;
 501                case Opt_oldalloc:
 502                        set_opt (sbi->s_mount_opt, OLDALLOC);
 503                        break;
 504                case Opt_orlov:
 505                        clear_opt (sbi->s_mount_opt, OLDALLOC);
 506                        break;
 507                case Opt_nobh:
 508                        set_opt (sbi->s_mount_opt, NOBH);
 509                        break;
 510#ifdef CONFIG_EXT2_FS_XATTR
 511                case Opt_user_xattr:
 512                        set_opt (sbi->s_mount_opt, XATTR_USER);
 513                        break;
 514                case Opt_nouser_xattr:
 515                        clear_opt (sbi->s_mount_opt, XATTR_USER);
 516                        break;
 517#else
 518                case Opt_user_xattr:
 519                case Opt_nouser_xattr:
 520                        ext2_msg(sb, KERN_INFO, "(no)user_xattr options"
 521                                "not supported");
 522                        break;
 523#endif
 524#ifdef CONFIG_EXT2_FS_POSIX_ACL
 525                case Opt_acl:
 526                        set_opt(sbi->s_mount_opt, POSIX_ACL);
 527                        break;
 528                case Opt_noacl:
 529                        clear_opt(sbi->s_mount_opt, POSIX_ACL);
 530                        break;
 531#else
 532                case Opt_acl:
 533                case Opt_noacl:
 534                        ext2_msg(sb, KERN_INFO,
 535                                "(no)acl options not supported");
 536                        break;
 537#endif
 538                case Opt_xip:
 539#ifdef CONFIG_EXT2_FS_XIP
 540                        set_opt (sbi->s_mount_opt, XIP);
 541#else
 542                        ext2_msg(sb, KERN_INFO, "xip option not supported");
 543#endif
 544                        break;
 545
 546#if defined(CONFIG_QUOTA)
 547                case Opt_quota:
 548                case Opt_usrquota:
 549                        set_opt(sbi->s_mount_opt, USRQUOTA);
 550                        break;
 551
 552                case Opt_grpquota:
 553                        set_opt(sbi->s_mount_opt, GRPQUOTA);
 554                        break;
 555#else
 556                case Opt_quota:
 557                case Opt_usrquota:
 558                case Opt_grpquota:
 559                        ext2_msg(sb, KERN_INFO,
 560                                "quota operations not supported");
 561                        break;
 562#endif
 563
 564                case Opt_reservation:
 565                        set_opt(sbi->s_mount_opt, RESERVATION);
 566                        ext2_msg(sb, KERN_INFO, "reservations ON");
 567                        break;
 568                case Opt_noreservation:
 569                        clear_opt(sbi->s_mount_opt, RESERVATION);
 570                        ext2_msg(sb, KERN_INFO, "reservations OFF");
 571                        break;
 572                case Opt_ignore:
 573                        break;
 574                default:
 575                        return 0;
 576                }
 577        }
 578        return 1;
 579}
 580
 581static int ext2_setup_super (struct super_block * sb,
 582                              struct ext2_super_block * es,
 583                              int read_only)
 584{
 585        int res = 0;
 586        struct ext2_sb_info *sbi = EXT2_SB(sb);
 587
 588        if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 589                ext2_msg(sb, KERN_ERR,
 590                        "error: revision level too high, "
 591                        "forcing read-only mode");
 592                res = MS_RDONLY;
 593        }
 594        if (read_only)
 595                return res;
 596        if (!(sbi->s_mount_state & EXT2_VALID_FS))
 597                ext2_msg(sb, KERN_WARNING,
 598                        "warning: mounting unchecked fs, "
 599                        "running e2fsck is recommended");
 600        else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 601                ext2_msg(sb, KERN_WARNING,
 602                        "warning: mounting fs with errors, "
 603                        "running e2fsck is recommended");
 604        else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 605                 le16_to_cpu(es->s_mnt_count) >=
 606                 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 607                ext2_msg(sb, KERN_WARNING,
 608                        "warning: maximal mount count reached, "
 609                        "running e2fsck is recommended");
 610        else if (le32_to_cpu(es->s_checkinterval) &&
 611                (le32_to_cpu(es->s_lastcheck) +
 612                        le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 613                ext2_msg(sb, KERN_WARNING,
 614                        "warning: checktime reached, "
 615                        "running e2fsck is recommended");
 616        if (!le16_to_cpu(es->s_max_mnt_count))
 617                es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 618        le16_add_cpu(&es->s_mnt_count, 1);
 619        if (test_opt (sb, DEBUG))
 620                ext2_msg(sb, KERN_INFO, "%s, %s, bs=%lu, fs=%lu, gc=%lu, "
 621                        "bpg=%lu, ipg=%lu, mo=%04lx]",
 622                        EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 623                        sbi->s_frag_size,
 624                        sbi->s_groups_count,
 625                        EXT2_BLOCKS_PER_GROUP(sb),
 626                        EXT2_INODES_PER_GROUP(sb),
 627                        sbi->s_mount_opt);
 628        return res;
 629}
 630
 631static int ext2_check_descriptors(struct super_block *sb)
 632{
 633        int i;
 634        struct ext2_sb_info *sbi = EXT2_SB(sb);
 635
 636        ext2_debug ("Checking group descriptors");
 637
 638        for (i = 0; i < sbi->s_groups_count; i++) {
 639                struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
 640                ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
 641                ext2_fsblk_t last_block;
 642
 643                if (i == sbi->s_groups_count - 1)
 644                        last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
 645                else
 646                        last_block = first_block +
 647                                (EXT2_BLOCKS_PER_GROUP(sb) - 1);
 648
 649                if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
 650                    le32_to_cpu(gdp->bg_block_bitmap) > last_block)
 651                {
 652                        ext2_error (sb, "ext2_check_descriptors",
 653                                    "Block bitmap for group %d"
 654                                    " not in group (block %lu)!",
 655                                    i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 656                        return 0;
 657                }
 658                if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
 659                    le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
 660                {
 661                        ext2_error (sb, "ext2_check_descriptors",
 662                                    "Inode bitmap for group %d"
 663                                    " not in group (block %lu)!",
 664                                    i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 665                        return 0;
 666                }
 667                if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
 668                    le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
 669                    last_block)
 670                {
 671                        ext2_error (sb, "ext2_check_descriptors",
 672                                    "Inode table for group %d"
 673                                    " not in group (block %lu)!",
 674                                    i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 675                        return 0;
 676                }
 677        }
 678        return 1;
 679}
 680
 681/*
 682 * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 683 * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 684 * We need to be 1 filesystem block less than the 2^32 sector limit.
 685 */
 686static loff_t ext2_max_size(int bits)
 687{
 688        loff_t res = EXT2_NDIR_BLOCKS;
 689        int meta_blocks;
 690        loff_t upper_limit;
 691
 692        /* This is calculated to be the largest file size for a
 693         * dense, file such that the total number of
 694         * sectors in the file, including data and all indirect blocks,
 695         * does not exceed 2^32 -1
 696         * __u32 i_blocks representing the total number of
 697         * 512 bytes blocks of the file
 698         */
 699        upper_limit = (1LL << 32) - 1;
 700
 701        /* total blocks in file system block size */
 702        upper_limit >>= (bits - 9);
 703
 704
 705        /* indirect blocks */
 706        meta_blocks = 1;
 707        /* double indirect blocks */
 708        meta_blocks += 1 + (1LL << (bits-2));
 709        /* tripple indirect blocks */
 710        meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
 711
 712        upper_limit -= meta_blocks;
 713        upper_limit <<= bits;
 714
 715        res += 1LL << (bits-2);
 716        res += 1LL << (2*(bits-2));
 717        res += 1LL << (3*(bits-2));
 718        res <<= bits;
 719        if (res > upper_limit)
 720                res = upper_limit;
 721
 722        if (res > MAX_LFS_FILESIZE)
 723                res = MAX_LFS_FILESIZE;
 724
 725        return res;
 726}
 727
 728static unsigned long descriptor_loc(struct super_block *sb,
 729                                    unsigned long logic_sb_block,
 730                                    int nr)
 731{
 732        struct ext2_sb_info *sbi = EXT2_SB(sb);
 733        unsigned long bg, first_meta_bg;
 734        int has_super = 0;
 735        
 736        first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 737
 738        if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 739            nr < first_meta_bg)
 740                return (logic_sb_block + nr + 1);
 741        bg = sbi->s_desc_per_block * nr;
 742        if (ext2_bg_has_super(sb, bg))
 743                has_super = 1;
 744
 745        return ext2_group_first_block_no(sb, bg) + has_super;
 746}
 747
 748static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 749{
 750        struct buffer_head * bh;
 751        struct ext2_sb_info * sbi;
 752        struct ext2_super_block * es;
 753        struct inode *root;
 754        unsigned long block;
 755        unsigned long sb_block = get_sb_block(&data);
 756        unsigned long logic_sb_block;
 757        unsigned long offset = 0;
 758        unsigned long def_mount_opts;
 759        long ret = -EINVAL;
 760        int blocksize = BLOCK_SIZE;
 761        int db_count;
 762        int i, j;
 763        __le32 features;
 764        int err;
 765
 766        err = -ENOMEM;
 767        sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 768        if (!sbi)
 769                goto failed_unlock;
 770
 771        sbi->s_blockgroup_lock =
 772                kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
 773        if (!sbi->s_blockgroup_lock) {
 774                kfree(sbi);
 775                goto failed_unlock;
 776        }
 777        sb->s_fs_info = sbi;
 778        sbi->s_sb_block = sb_block;
 779
 780        spin_lock_init(&sbi->s_lock);
 781
 782        /*
 783         * See what the current blocksize for the device is, and
 784         * use that as the blocksize.  Otherwise (or if the blocksize
 785         * is smaller than the default) use the default.
 786         * This is important for devices that have a hardware
 787         * sectorsize that is larger than the default.
 788         */
 789        blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 790        if (!blocksize) {
 791                ext2_msg(sb, KERN_ERR, "error: unable to set blocksize");
 792                goto failed_sbi;
 793        }
 794
 795        /*
 796         * If the superblock doesn't start on a hardware sector boundary,
 797         * calculate the offset.  
 798         */
 799        if (blocksize != BLOCK_SIZE) {
 800                logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 801                offset = (sb_block*BLOCK_SIZE) % blocksize;
 802        } else {
 803                logic_sb_block = sb_block;
 804        }
 805
 806        if (!(bh = sb_bread(sb, logic_sb_block))) {
 807                ext2_msg(sb, KERN_ERR, "error: unable to read superblock");
 808                goto failed_sbi;
 809        }
 810        /*
 811         * Note: s_es must be initialized as soon as possible because
 812         *       some ext2 macro-instructions depend on its value
 813         */
 814        es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 815        sbi->s_es = es;
 816        sb->s_magic = le16_to_cpu(es->s_magic);
 817
 818        if (sb->s_magic != EXT2_SUPER_MAGIC)
 819                goto cantfind_ext2;
 820
 821        /* Set defaults before we parse the mount options */
 822        def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 823        if (def_mount_opts & EXT2_DEFM_DEBUG)
 824                set_opt(sbi->s_mount_opt, DEBUG);
 825        if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 826                set_opt(sbi->s_mount_opt, GRPID);
 827        if (def_mount_opts & EXT2_DEFM_UID16)
 828                set_opt(sbi->s_mount_opt, NO_UID32);
 829#ifdef CONFIG_EXT2_FS_XATTR
 830        if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 831                set_opt(sbi->s_mount_opt, XATTR_USER);
 832#endif
 833#ifdef CONFIG_EXT2_FS_POSIX_ACL
 834        if (def_mount_opts & EXT2_DEFM_ACL)
 835                set_opt(sbi->s_mount_opt, POSIX_ACL);
 836#endif
 837        
 838        if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 839                set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 840        else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
 841                set_opt(sbi->s_mount_opt, ERRORS_CONT);
 842        else
 843                set_opt(sbi->s_mount_opt, ERRORS_RO);
 844
 845        sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
 846        sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
 847        
 848        set_opt(sbi->s_mount_opt, RESERVATION);
 849
 850        if (!parse_options((char *) data, sb))
 851                goto failed_mount;
 852
 853        sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 854                ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 855                 MS_POSIXACL : 0);
 856
 857        ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
 858                                    EXT2_MOUNT_XIP if not */
 859
 860        if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 861            (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 862             EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 863             EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 864                ext2_msg(sb, KERN_WARNING,
 865                        "warning: feature flags set on rev 0 fs, "
 866                        "running e2fsck is recommended");
 867        /*
 868         * Check feature flags regardless of the revision level, since we
 869         * previously didn't change the revision level when setting the flags,
 870         * so there is a chance incompat flags are set on a rev 0 filesystem.
 871         */
 872        features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 873        if (features) {
 874                ext2_msg(sb, KERN_ERR,  "error: couldn't mount because of "
 875                       "unsupported optional features (%x)",
 876                        le32_to_cpu(features));
 877                goto failed_mount;
 878        }
 879        if (!(sb->s_flags & MS_RDONLY) &&
 880            (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 881                ext2_msg(sb, KERN_ERR, "error: couldn't mount RDWR because of "
 882                       "unsupported optional features (%x)",
 883                       le32_to_cpu(features));
 884                goto failed_mount;
 885        }
 886
 887        blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 888
 889        if (ext2_use_xip(sb) && blocksize != PAGE_SIZE) {
 890                if (!silent)
 891                        ext2_msg(sb, KERN_ERR,
 892                                "error: unsupported blocksize for xip");
 893                goto failed_mount;
 894        }
 895
 896        /* If the blocksize doesn't match, re-read the thing.. */
 897        if (sb->s_blocksize != blocksize) {
 898                brelse(bh);
 899
 900                if (!sb_set_blocksize(sb, blocksize)) {
 901                        ext2_msg(sb, KERN_ERR,
 902                                "error: bad blocksize %d", blocksize);
 903                        goto failed_sbi;
 904                }
 905
 906                logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 907                offset = (sb_block*BLOCK_SIZE) % blocksize;
 908                bh = sb_bread(sb, logic_sb_block);
 909                if(!bh) {
 910                        ext2_msg(sb, KERN_ERR, "error: couldn't read"
 911                                "superblock on 2nd try");
 912                        goto failed_sbi;
 913                }
 914                es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 915                sbi->s_es = es;
 916                if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 917                        ext2_msg(sb, KERN_ERR, "error: magic mismatch");
 918                        goto failed_mount;
 919                }
 920        }
 921
 922        sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 923
 924        if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 925                sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 926                sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 927        } else {
 928                sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 929                sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 930                if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 931                    !is_power_of_2(sbi->s_inode_size) ||
 932                    (sbi->s_inode_size > blocksize)) {
 933                        ext2_msg(sb, KERN_ERR,
 934                                "error: unsupported inode size: %d",
 935                                sbi->s_inode_size);
 936                        goto failed_mount;
 937                }
 938        }
 939
 940        sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 941                                   le32_to_cpu(es->s_log_frag_size);
 942        if (sbi->s_frag_size == 0)
 943                goto cantfind_ext2;
 944        sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
 945
 946        sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 947        sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 948        sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 949
 950        if (EXT2_INODE_SIZE(sb) == 0)
 951                goto cantfind_ext2;
 952        sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
 953        if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
 954                goto cantfind_ext2;
 955        sbi->s_itb_per_group = sbi->s_inodes_per_group /
 956                                        sbi->s_inodes_per_block;
 957        sbi->s_desc_per_block = sb->s_blocksize /
 958                                        sizeof (struct ext2_group_desc);
 959        sbi->s_sbh = bh;
 960        sbi->s_mount_state = le16_to_cpu(es->s_state);
 961        sbi->s_addr_per_block_bits =
 962                ilog2 (EXT2_ADDR_PER_BLOCK(sb));
 963        sbi->s_desc_per_block_bits =
 964                ilog2 (EXT2_DESC_PER_BLOCK(sb));
 965
 966        if (sb->s_magic != EXT2_SUPER_MAGIC)
 967                goto cantfind_ext2;
 968
 969        if (sb->s_blocksize != bh->b_size) {
 970                if (!silent)
 971                        ext2_msg(sb, KERN_ERR, "error: unsupported blocksize");
 972                goto failed_mount;
 973        }
 974
 975        if (sb->s_blocksize != sbi->s_frag_size) {
 976                ext2_msg(sb, KERN_ERR,
 977                        "error: fragsize %lu != blocksize %lu"
 978                        "(not supported yet)",
 979                        sbi->s_frag_size, sb->s_blocksize);
 980                goto failed_mount;
 981        }
 982
 983        if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
 984                ext2_msg(sb, KERN_ERR,
 985                        "error: #blocks per group too big: %lu",
 986                        sbi->s_blocks_per_group);
 987                goto failed_mount;
 988        }
 989        if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 990                ext2_msg(sb, KERN_ERR,
 991                        "error: #fragments per group too big: %lu",
 992                        sbi->s_frags_per_group);
 993                goto failed_mount;
 994        }
 995        if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
 996                ext2_msg(sb, KERN_ERR,
 997                        "error: #inodes per group too big: %lu",
 998                        sbi->s_inodes_per_group);
 999                goto failed_mount;
1000        }
1001
1002        if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
1003                goto cantfind_ext2;
1004        sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
1005                                le32_to_cpu(es->s_first_data_block) - 1)
1006                                        / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
1007        db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
1008                   EXT2_DESC_PER_BLOCK(sb);
1009        sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
1010        if (sbi->s_group_desc == NULL) {
1011                ext2_msg(sb, KERN_ERR, "error: not enough memory");
1012                goto failed_mount;
1013        }
1014        bgl_lock_init(sbi->s_blockgroup_lock);
1015        sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
1016        if (!sbi->s_debts) {
1017                ext2_msg(sb, KERN_ERR, "error: not enough memory");
1018                goto failed_mount_group_desc;
1019        }
1020        for (i = 0; i < db_count; i++) {
1021                block = descriptor_loc(sb, logic_sb_block, i);
1022                sbi->s_group_desc[i] = sb_bread(sb, block);
1023                if (!sbi->s_group_desc[i]) {
1024                        for (j = 0; j < i; j++)
1025                                brelse (sbi->s_group_desc[j]);
1026                        ext2_msg(sb, KERN_ERR,
1027                                "error: unable to read group descriptors");
1028                        goto failed_mount_group_desc;
1029                }
1030        }
1031        if (!ext2_check_descriptors (sb)) {
1032                ext2_msg(sb, KERN_ERR, "group descriptors corrupted");
1033                goto failed_mount2;
1034        }
1035        sbi->s_gdb_count = db_count;
1036        get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1037        spin_lock_init(&sbi->s_next_gen_lock);
1038
1039        /* per fileystem reservation list head & lock */
1040        spin_lock_init(&sbi->s_rsv_window_lock);
1041        sbi->s_rsv_window_root = RB_ROOT;
1042        /*
1043         * Add a single, static dummy reservation to the start of the
1044         * reservation window list --- it gives us a placeholder for
1045         * append-at-start-of-list which makes the allocation logic
1046         * _much_ simpler.
1047         */
1048        sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1049        sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1050        sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1051        sbi->s_rsv_window_head.rsv_goal_size = 0;
1052        ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1053
1054        err = percpu_counter_init(&sbi->s_freeblocks_counter,
1055                                ext2_count_free_blocks(sb));
1056        if (!err) {
1057                err = percpu_counter_init(&sbi->s_freeinodes_counter,
1058                                ext2_count_free_inodes(sb));
1059        }
1060        if (!err) {
1061                err = percpu_counter_init(&sbi->s_dirs_counter,
1062                                ext2_count_dirs(sb));
1063        }
1064        if (err) {
1065                ext2_msg(sb, KERN_ERR, "error: insufficient memory");
1066                goto failed_mount3;
1067        }
1068        /*
1069         * set up enough so that it can read an inode
1070         */
1071        sb->s_op = &ext2_sops;
1072        sb->s_export_op = &ext2_export_ops;
1073        sb->s_xattr = ext2_xattr_handlers;
1074
1075#ifdef CONFIG_QUOTA
1076        sb->dq_op = &dquot_operations;
1077        sb->s_qcop = &dquot_quotactl_ops;
1078#endif
1079
1080        root = ext2_iget(sb, EXT2_ROOT_INO);
1081        if (IS_ERR(root)) {
1082                ret = PTR_ERR(root);
1083                goto failed_mount3;
1084        }
1085        if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1086                iput(root);
1087                ext2_msg(sb, KERN_ERR, "error: corrupt root inode, run e2fsck");
1088                goto failed_mount3;
1089        }
1090
1091        sb->s_root = d_alloc_root(root);
1092        if (!sb->s_root) {
1093                iput(root);
1094                ext2_msg(sb, KERN_ERR, "error: get root inode failed");
1095                ret = -ENOMEM;
1096                goto failed_mount3;
1097        }
1098        if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1099                ext2_msg(sb, KERN_WARNING,
1100                        "warning: mounting ext3 filesystem as ext2");
1101        if (ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY))
1102                sb->s_flags |= MS_RDONLY;
1103        ext2_write_super(sb);
1104        return 0;
1105
1106cantfind_ext2:
1107        if (!silent)
1108                ext2_msg(sb, KERN_ERR,
1109                        "error: can't find an ext2 filesystem on dev %s.",
1110                        sb->s_id);
1111        goto failed_mount;
1112failed_mount3:
1113        percpu_counter_destroy(&sbi->s_freeblocks_counter);
1114        percpu_counter_destroy(&sbi->s_freeinodes_counter);
1115        percpu_counter_destroy(&sbi->s_dirs_counter);
1116failed_mount2:
1117        for (i = 0; i < db_count; i++)
1118                brelse(sbi->s_group_desc[i]);
1119failed_mount_group_desc:
1120        kfree(sbi->s_group_desc);
1121        kfree(sbi->s_debts);
1122failed_mount:
1123        brelse(bh);
1124failed_sbi:
1125        sb->s_fs_info = NULL;
1126        kfree(sbi->s_blockgroup_lock);
1127        kfree(sbi);
1128failed_unlock:
1129        return ret;
1130}
1131
1132static void ext2_clear_super_error(struct super_block *sb)
1133{
1134        struct buffer_head *sbh = EXT2_SB(sb)->s_sbh;
1135
1136        if (buffer_write_io_error(sbh)) {
1137                /*
1138                 * Oh, dear.  A previous attempt to write the
1139                 * superblock failed.  This could happen because the
1140                 * USB device was yanked out.  Or it could happen to
1141                 * be a transient write error and maybe the block will
1142                 * be remapped.  Nothing we can do but to retry the
1143                 * write and hope for the best.
1144                 */
1145                ext2_msg(sb, KERN_ERR,
1146                       "previous I/O error to superblock detected\n");
1147                clear_buffer_write_io_error(sbh);
1148                set_buffer_uptodate(sbh);
1149        }
1150}
1151
1152static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
1153                            int wait)
1154{
1155        ext2_clear_super_error(sb);
1156        spin_lock(&EXT2_SB(sb)->s_lock);
1157        es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1158        es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1159        es->s_wtime = cpu_to_le32(get_seconds());
1160        /* unlock before we do IO */
1161        spin_unlock(&EXT2_SB(sb)->s_lock);
1162        mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1163        if (wait)
1164                sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1165        sb->s_dirt = 0;
1166}
1167
1168/*
1169 * In the second extended file system, it is not necessary to
1170 * write the super block since we use a mapping of the
1171 * disk super block in a buffer.
1172 *
1173 * However, this function is still used to set the fs valid
1174 * flags to 0.  We need to set this flag to 0 since the fs
1175 * may have been checked while mounted and e2fsck may have
1176 * set s_state to EXT2_VALID_FS after some corrections.
1177 */
1178static int ext2_sync_fs(struct super_block *sb, int wait)
1179{
1180        struct ext2_sb_info *sbi = EXT2_SB(sb);
1181        struct ext2_super_block *es = EXT2_SB(sb)->s_es;
1182
1183        spin_lock(&sbi->s_lock);
1184        if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1185                ext2_debug("setting valid to 0\n");
1186                es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1187        }
1188        spin_unlock(&sbi->s_lock);
1189        ext2_sync_super(sb, es, wait);
1190        return 0;
1191}
1192
1193
1194void ext2_write_super(struct super_block *sb)
1195{
1196        if (!(sb->s_flags & MS_RDONLY))
1197                ext2_sync_fs(sb, 1);
1198        else
1199                sb->s_dirt = 0;
1200}
1201
1202static int ext2_remount (struct super_block * sb, int * flags, char * data)
1203{
1204        struct ext2_sb_info * sbi = EXT2_SB(sb);
1205        struct ext2_super_block * es;
1206        unsigned long old_mount_opt = sbi->s_mount_opt;
1207        struct ext2_mount_options old_opts;
1208        unsigned long old_sb_flags;
1209        int err;
1210
1211        spin_lock(&sbi->s_lock);
1212
1213        /* Store the old options */
1214        old_sb_flags = sb->s_flags;
1215        old_opts.s_mount_opt = sbi->s_mount_opt;
1216        old_opts.s_resuid = sbi->s_resuid;
1217        old_opts.s_resgid = sbi->s_resgid;
1218
1219        /*
1220         * Allow the "check" option to be passed as a remount option.
1221         */
1222        if (!parse_options(data, sb)) {
1223                err = -EINVAL;
1224                goto restore_opts;
1225        }
1226
1227        sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1228                ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1229
1230        ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
1231                                    EXT2_MOUNT_XIP if not */
1232
1233        if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
1234                ext2_msg(sb, KERN_WARNING,
1235                        "warning: unsupported blocksize for xip");
1236                err = -EINVAL;
1237                goto restore_opts;
1238        }
1239
1240        es = sbi->s_es;
1241        if ((sbi->s_mount_opt ^ old_mount_opt) & EXT2_MOUNT_XIP) {
1242                ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
1243                         "xip flag with busy inodes while remounting");
1244                sbi->s_mount_opt &= ~EXT2_MOUNT_XIP;
1245                sbi->s_mount_opt |= old_mount_opt & EXT2_MOUNT_XIP;
1246        }
1247        if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
1248                spin_unlock(&sbi->s_lock);
1249                return 0;
1250        }
1251        if (*flags & MS_RDONLY) {
1252                if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1253                    !(sbi->s_mount_state & EXT2_VALID_FS)) {
1254                        spin_unlock(&sbi->s_lock);
1255                        return 0;
1256                }
1257
1258                /*
1259                 * OK, we are remounting a valid rw partition rdonly, so set
1260                 * the rdonly flag and then mark the partition as valid again.
1261                 */
1262                es->s_state = cpu_to_le16(sbi->s_mount_state);
1263                es->s_mtime = cpu_to_le32(get_seconds());
1264                spin_unlock(&sbi->s_lock);
1265
1266                err = dquot_suspend(sb, -1);
1267                if (err < 0) {
1268                        spin_lock(&sbi->s_lock);
1269                        goto restore_opts;
1270                }
1271
1272                ext2_sync_super(sb, es, 1);
1273        } else {
1274                __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1275                                               ~EXT2_FEATURE_RO_COMPAT_SUPP);
1276                if (ret) {
1277                        ext2_msg(sb, KERN_WARNING,
1278                                "warning: couldn't remount RDWR because of "
1279                                "unsupported optional features (%x).",
1280                                le32_to_cpu(ret));
1281                        err = -EROFS;
1282                        goto restore_opts;
1283                }
1284                /*
1285                 * Mounting a RDONLY partition read-write, so reread and
1286                 * store the current valid flag.  (It may have been changed
1287                 * by e2fsck since we originally mounted the partition.)
1288                 */
1289                sbi->s_mount_state = le16_to_cpu(es->s_state);
1290                if (!ext2_setup_super (sb, es, 0))
1291                        sb->s_flags &= ~MS_RDONLY;
1292                spin_unlock(&sbi->s_lock);
1293
1294                ext2_write_super(sb);
1295
1296                dquot_resume(sb, -1);
1297        }
1298
1299        return 0;
1300restore_opts:
1301        sbi->s_mount_opt = old_opts.s_mount_opt;
1302        sbi->s_resuid = old_opts.s_resuid;
1303        sbi->s_resgid = old_opts.s_resgid;
1304        sb->s_flags = old_sb_flags;
1305        spin_unlock(&sbi->s_lock);
1306        return err;
1307}
1308
1309static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1310{
1311        struct super_block *sb = dentry->d_sb;
1312        struct ext2_sb_info *sbi = EXT2_SB(sb);
1313        struct ext2_super_block *es = sbi->s_es;
1314        u64 fsid;
1315
1316        spin_lock(&sbi->s_lock);
1317
1318        if (test_opt (sb, MINIX_DF))
1319                sbi->s_overhead_last = 0;
1320        else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1321                unsigned long i, overhead = 0;
1322                smp_rmb();
1323
1324                /*
1325                 * Compute the overhead (FS structures). This is constant
1326                 * for a given filesystem unless the number of block groups
1327                 * changes so we cache the previous value until it does.
1328                 */
1329
1330                /*
1331                 * All of the blocks before first_data_block are
1332                 * overhead
1333                 */
1334                overhead = le32_to_cpu(es->s_first_data_block);
1335
1336                /*
1337                 * Add the overhead attributed to the superblock and
1338                 * block group descriptors.  If the sparse superblocks
1339                 * feature is turned on, then not all groups have this.
1340                 */
1341                for (i = 0; i < sbi->s_groups_count; i++)
1342                        overhead += ext2_bg_has_super(sb, i) +
1343                                ext2_bg_num_gdb(sb, i);
1344
1345                /*
1346                 * Every block group has an inode bitmap, a block
1347                 * bitmap, and an inode table.
1348                 */
1349                overhead += (sbi->s_groups_count *
1350                             (2 + sbi->s_itb_per_group));
1351                sbi->s_overhead_last = overhead;
1352                smp_wmb();
1353                sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1354        }
1355
1356        buf->f_type = EXT2_SUPER_MAGIC;
1357        buf->f_bsize = sb->s_blocksize;
1358        buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1359        buf->f_bfree = ext2_count_free_blocks(sb);
1360        es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1361        buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1362        if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1363                buf->f_bavail = 0;
1364        buf->f_files = le32_to_cpu(es->s_inodes_count);
1365        buf->f_ffree = ext2_count_free_inodes(sb);
1366        es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1367        buf->f_namelen = EXT2_NAME_LEN;
1368        fsid = le64_to_cpup((void *)es->s_uuid) ^
1369               le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1370        buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1371        buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1372        spin_unlock(&sbi->s_lock);
1373        return 0;
1374}
1375
1376static struct dentry *ext2_mount(struct file_system_type *fs_type,
1377        int flags, const char *dev_name, void *data)
1378{
1379        return mount_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1380}
1381
1382#ifdef CONFIG_QUOTA
1383
1384/* Read data from quotafile - avoid pagecache and such because we cannot afford
1385 * acquiring the locks... As quota files are never truncated and quota code
1386 * itself serializes the operations (and no one else should touch the files)
1387 * we don't have to be afraid of races */
1388static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1389                               size_t len, loff_t off)
1390{
1391        struct inode *inode = sb_dqopt(sb)->files[type];
1392        sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1393        int err = 0;
1394        int offset = off & (sb->s_blocksize - 1);
1395        int tocopy;
1396        size_t toread;
1397        struct buffer_head tmp_bh;
1398        struct buffer_head *bh;
1399        loff_t i_size = i_size_read(inode);
1400
1401        if (off > i_size)
1402                return 0;
1403        if (off+len > i_size)
1404                len = i_size-off;
1405        toread = len;
1406        while (toread > 0) {
1407                tocopy = sb->s_blocksize - offset < toread ?
1408                                sb->s_blocksize - offset : toread;
1409
1410                tmp_bh.b_state = 0;
1411                tmp_bh.b_size = sb->s_blocksize;
1412                err = ext2_get_block(inode, blk, &tmp_bh, 0);
1413                if (err < 0)
1414                        return err;
1415                if (!buffer_mapped(&tmp_bh))    /* A hole? */
1416                        memset(data, 0, tocopy);
1417                else {
1418                        bh = sb_bread(sb, tmp_bh.b_blocknr);
1419                        if (!bh)
1420                                return -EIO;
1421                        memcpy(data, bh->b_data+offset, tocopy);
1422                        brelse(bh);
1423                }
1424                offset = 0;
1425                toread -= tocopy;
1426                data += tocopy;
1427                blk++;
1428        }
1429        return len;
1430}
1431
1432/* Write to quotafile */
1433static ssize_t ext2_quota_write(struct super_block *sb, int type,
1434                                const char *data, size_t len, loff_t off)
1435{
1436        struct inode *inode = sb_dqopt(sb)->files[type];
1437        sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1438        int err = 0;
1439        int offset = off & (sb->s_blocksize - 1);
1440        int tocopy;
1441        size_t towrite = len;
1442        struct buffer_head tmp_bh;
1443        struct buffer_head *bh;
1444
1445        mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1446        while (towrite > 0) {
1447                tocopy = sb->s_blocksize - offset < towrite ?
1448                                sb->s_blocksize - offset : towrite;
1449
1450                tmp_bh.b_state = 0;
1451                err = ext2_get_block(inode, blk, &tmp_bh, 1);
1452                if (err < 0)
1453                        goto out;
1454                if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1455                        bh = sb_bread(sb, tmp_bh.b_blocknr);
1456                else
1457                        bh = sb_getblk(sb, tmp_bh.b_blocknr);
1458                if (!bh) {
1459                        err = -EIO;
1460                        goto out;
1461                }
1462                lock_buffer(bh);
1463                memcpy(bh->b_data+offset, data, tocopy);
1464                flush_dcache_page(bh->b_page);
1465                set_buffer_uptodate(bh);
1466                mark_buffer_dirty(bh);
1467                unlock_buffer(bh);
1468                brelse(bh);
1469                offset = 0;
1470                towrite -= tocopy;
1471                data += tocopy;
1472                blk++;
1473        }
1474out:
1475        if (len == towrite) {
1476                mutex_unlock(&inode->i_mutex);
1477                return err;
1478        }
1479        if (inode->i_size < off+len-towrite)
1480                i_size_write(inode, off+len-towrite);
1481        inode->i_version++;
1482        inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1483        mark_inode_dirty(inode);
1484        mutex_unlock(&inode->i_mutex);
1485        return len - towrite;
1486}
1487
1488#endif
1489
1490static struct file_system_type ext2_fs_type = {
1491        .owner          = THIS_MODULE,
1492        .name           = "ext2",
1493        .mount          = ext2_mount,
1494        .kill_sb        = kill_block_super,
1495        .fs_flags       = FS_REQUIRES_DEV,
1496};
1497
1498static int __init init_ext2_fs(void)
1499{
1500        int err = init_ext2_xattr();
1501        if (err)
1502                return err;
1503        err = init_inodecache();
1504        if (err)
1505                goto out1;
1506        err = register_filesystem(&ext2_fs_type);
1507        if (err)
1508                goto out;
1509        return 0;
1510out:
1511        destroy_inodecache();
1512out1:
1513        exit_ext2_xattr();
1514        return err;
1515}
1516
1517static void __exit exit_ext2_fs(void)
1518{
1519        unregister_filesystem(&ext2_fs_type);
1520        destroy_inodecache();
1521        exit_ext2_xattr();
1522}
1523
1524module_init(init_ext2_fs)
1525module_exit(exit_ext2_fs)
1526
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