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
  39static void ext2_sync_super(struct super_block *sb,
  40                            struct ext2_super_block *es, int wait);
  41static int ext2_remount (struct super_block * sb, int * flags, char * data);
  42static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
  43static int ext2_sync_fs(struct super_block *sb, int wait);
  44static int ext2_freeze(struct super_block *sb);
  45static int ext2_unfreeze(struct super_block *sb);
  46
  47void ext2_error(struct super_block *sb, const char *function,
  48                const char *fmt, ...)
  49{
  50        struct va_format vaf;
  51        va_list args;
  52        struct ext2_sb_info *sbi = EXT2_SB(sb);
  53        struct ext2_super_block *es = sbi->s_es;
  54
  55        if (!(sb->s_flags & MS_RDONLY)) {
  56                spin_lock(&sbi->s_lock);
  57                sbi->s_mount_state |= EXT2_ERROR_FS;
  58                es->s_state |= cpu_to_le16(EXT2_ERROR_FS);
  59                spin_unlock(&sbi->s_lock);
  60                ext2_sync_super(sb, es, 1);
  61        }
  62
  63        va_start(args, fmt);
  64
  65        vaf.fmt = fmt;
  66        vaf.va = &args;
  67
  68        printk(KERN_CRIT "EXT2-fs (%s): error: %s: %pV\n",
  69               sb->s_id, function, &vaf);
  70
  71        va_end(args);
  72
  73        if (test_opt(sb, ERRORS_PANIC))
  74                panic("EXT2-fs: panic from previous error\n");
  75        if (test_opt(sb, ERRORS_RO)) {
  76                ext2_msg(sb, KERN_CRIT,
  77                             "error: remounting filesystem read-only");
  78                sb->s_flags |= MS_RDONLY;
  79        }
  80}
  81
  82void ext2_msg(struct super_block *sb, const char *prefix,
  83                const char *fmt, ...)
  84{
  85        struct va_format vaf;
  86        va_list args;
  87
  88        va_start(args, fmt);
  89
  90        vaf.fmt = fmt;
  91        vaf.va = &args;
  92
  93        printk("%sEXT2-fs (%s): %pV\n", prefix, sb->s_id, &vaf);
  94
  95        va_end(args);
  96}
  97
  98/*
  99 * This must be called with sbi->s_lock held.
 100 */
 101void ext2_update_dynamic_rev(struct super_block *sb)
 102{
 103        struct ext2_super_block *es = EXT2_SB(sb)->s_es;
 104
 105        if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
 106                return;
 107
 108        ext2_msg(sb, KERN_WARNING,
 109                     "warning: updating to rev %d because of "
 110                     "new feature flag, running e2fsck is recommended",
 111                     EXT2_DYNAMIC_REV);
 112
 113        es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
 114        es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
 115        es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
 116        /* leave es->s_feature_*compat flags alone */
 117        /* es->s_uuid will be set by e2fsck if empty */
 118
 119        /*
 120         * The rest of the superblock fields should be zero, and if not it
 121         * means they are likely already in use, so leave them alone.  We
 122         * can leave it up to e2fsck to clean up any inconsistencies there.
 123         */
 124}
 125
 126static void ext2_put_super (struct super_block * sb)
 127{
 128        int db_count;
 129        int i;
 130        struct ext2_sb_info *sbi = EXT2_SB(sb);
 131
 132        dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
 133
 134        ext2_xattr_put_super(sb);
 135        if (!(sb->s_flags & MS_RDONLY)) {
 136                struct ext2_super_block *es = sbi->s_es;
 137
 138                spin_lock(&sbi->s_lock);
 139                es->s_state = cpu_to_le16(sbi->s_mount_state);
 140                spin_unlock(&sbi->s_lock);
 141                ext2_sync_super(sb, es, 1);
 142        }
 143        db_count = sbi->s_gdb_count;
 144        for (i = 0; i < db_count; i++)
 145                if (sbi->s_group_desc[i])
 146                        brelse (sbi->s_group_desc[i]);
 147        kfree(sbi->s_group_desc);
 148        kfree(sbi->s_debts);
 149        percpu_counter_destroy(&sbi->s_freeblocks_counter);
 150        percpu_counter_destroy(&sbi->s_freeinodes_counter);
 151        percpu_counter_destroy(&sbi->s_dirs_counter);
 152        brelse (sbi->s_sbh);
 153        sb->s_fs_info = NULL;
 154        kfree(sbi->s_blockgroup_lock);
 155        kfree(sbi);
 156}
 157
 158static struct kmem_cache * ext2_inode_cachep;
 159
 160static struct inode *ext2_alloc_inode(struct super_block *sb)
 161{
 162        struct ext2_inode_info *ei;
 163        ei = kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
 164        if (!ei)
 165                return NULL;
 166        ei->i_block_alloc_info = NULL;
 167        ei->vfs_inode.i_version = 1;
 168#ifdef CONFIG_QUOTA
 169        memset(&ei->i_dquot, 0, sizeof(ei->i_dquot));
 170#endif
 171
 172        return &ei->vfs_inode;
 173}
 174
 175static void ext2_i_callback(struct rcu_head *head)
 176{
 177        struct inode *inode = container_of(head, struct inode, i_rcu);
 178        kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
 179}
 180
 181static void ext2_destroy_inode(struct inode *inode)
 182{
 183        call_rcu(&inode->i_rcu, ext2_i_callback);
 184}
 185
 186static void init_once(void *foo)
 187{
 188        struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
 189
 190        rwlock_init(&ei->i_meta_lock);
 191#ifdef CONFIG_EXT2_FS_XATTR
 192        init_rwsem(&ei->xattr_sem);
 193#endif
 194        mutex_init(&ei->truncate_mutex);
 195        inode_init_once(&ei->vfs_inode);
 196}
 197
 198static int __init init_inodecache(void)
 199{
 200        ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
 201                                             sizeof(struct ext2_inode_info),
 202                                             0, (SLAB_RECLAIM_ACCOUNT|
 203                                                SLAB_MEM_SPREAD),
 204                                             init_once);
 205        if (ext2_inode_cachep == NULL)
 206                return -ENOMEM;
 207        return 0;
 208}
 209
 210static void destroy_inodecache(void)
 211{
 212        /*
 213         * Make sure all delayed rcu free inodes are flushed before we
 214         * destroy cache.
 215         */
 216        rcu_barrier();
 217        kmem_cache_destroy(ext2_inode_cachep);
 218}
 219
 220static int ext2_show_options(struct seq_file *seq, struct dentry *root)
 221{
 222        struct super_block *sb = root->d_sb;
 223        struct ext2_sb_info *sbi = EXT2_SB(sb);
 224        struct ext2_super_block *es = sbi->s_es;
 225        unsigned long def_mount_opts;
 226
 227        spin_lock(&sbi->s_lock);
 228        def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 229
 230        if (sbi->s_sb_block != 1)
 231                seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
 232        if (test_opt(sb, MINIX_DF))
 233                seq_puts(seq, ",minixdf");
 234        if (test_opt(sb, GRPID))
 235                seq_puts(seq, ",grpid");
 236        if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
 237                seq_puts(seq, ",nogrpid");
 238        if (!uid_eq(sbi->s_resuid, make_kuid(&init_user_ns, EXT2_DEF_RESUID)) ||
 239            le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
 240                seq_printf(seq, ",resuid=%u",
 241                                from_kuid_munged(&init_user_ns, sbi->s_resuid));
 242        }
 243        if (!gid_eq(sbi->s_resgid, make_kgid(&init_user_ns, EXT2_DEF_RESGID)) ||
 244            le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
 245                seq_printf(seq, ",resgid=%u",
 246                                from_kgid_munged(&init_user_ns, sbi->s_resgid));
 247        }
 248        if (test_opt(sb, ERRORS_RO)) {
 249                int def_errors = le16_to_cpu(es->s_errors);
 250
 251                if (def_errors == EXT2_ERRORS_PANIC ||
 252                    def_errors == EXT2_ERRORS_CONTINUE) {
 253                        seq_puts(seq, ",errors=remount-ro");
 254                }
 255        }
 256        if (test_opt(sb, ERRORS_CONT))
 257                seq_puts(seq, ",errors=continue");
 258        if (test_opt(sb, ERRORS_PANIC))
 259                seq_puts(seq, ",errors=panic");
 260        if (test_opt(sb, NO_UID32))
 261                seq_puts(seq, ",nouid32");
 262        if (test_opt(sb, DEBUG))
 263                seq_puts(seq, ",debug");
 264        if (test_opt(sb, OLDALLOC))
 265                seq_puts(seq, ",oldalloc");
 266
 267#ifdef CONFIG_EXT2_FS_XATTR
 268        if (test_opt(sb, XATTR_USER))
 269                seq_puts(seq, ",user_xattr");
 270        if (!test_opt(sb, XATTR_USER) &&
 271            (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
 272                seq_puts(seq, ",nouser_xattr");
 273        }
 274#endif
 275
 276#ifdef CONFIG_EXT2_FS_POSIX_ACL
 277        if (test_opt(sb, POSIX_ACL))
 278                seq_puts(seq, ",acl");
 279        if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
 280                seq_puts(seq, ",noacl");
 281#endif
 282
 283        if (test_opt(sb, NOBH))
 284                seq_puts(seq, ",nobh");
 285
 286#if defined(CONFIG_QUOTA)
 287        if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
 288                seq_puts(seq, ",usrquota");
 289
 290        if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
 291                seq_puts(seq, ",grpquota");
 292#endif
 293
 294#ifdef CONFIG_FS_DAX
 295        if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
 296                seq_puts(seq, ",xip");
 297        if (sbi->s_mount_opt & EXT2_MOUNT_DAX)
 298                seq_puts(seq, ",dax");
 299#endif
 300
 301        if (!test_opt(sb, RESERVATION))
 302                seq_puts(seq, ",noreservation");
 303
 304        spin_unlock(&sbi->s_lock);
 305        return 0;
 306}
 307
 308#ifdef CONFIG_QUOTA
 309static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
 310static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
 311static struct dquot **ext2_get_dquots(struct inode *inode)
 312{
 313        return EXT2_I(inode)->i_dquot;
 314}
 315#endif
 316
 317static const struct super_operations ext2_sops = {
 318        .alloc_inode    = ext2_alloc_inode,
 319        .destroy_inode  = ext2_destroy_inode,
 320        .write_inode    = ext2_write_inode,
 321        .evict_inode    = ext2_evict_inode,
 322        .put_super      = ext2_put_super,
 323        .sync_fs        = ext2_sync_fs,
 324        .freeze_fs      = ext2_freeze,
 325        .unfreeze_fs    = ext2_unfreeze,
 326        .statfs         = ext2_statfs,
 327        .remount_fs     = ext2_remount,
 328        .show_options   = ext2_show_options,
 329#ifdef CONFIG_QUOTA
 330        .quota_read     = ext2_quota_read,
 331        .quota_write    = ext2_quota_write,
 332        .get_dquots     = ext2_get_dquots,
 333#endif
 334};
 335
 336static struct inode *ext2_nfs_get_inode(struct super_block *sb,
 337                u64 ino, u32 generation)
 338{
 339        struct inode *inode;
 340
 341        if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
 342                return ERR_PTR(-ESTALE);
 343        if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
 344                return ERR_PTR(-ESTALE);
 345
 346        /*
 347         * ext2_iget isn't quite right if the inode is currently unallocated!
 348         * However ext2_iget currently does appropriate checks to handle stale
 349         * inodes so everything is OK.
 350         */
 351        inode = ext2_iget(sb, ino);
 352        if (IS_ERR(inode))
 353                return ERR_CAST(inode);
 354        if (generation && inode->i_generation != generation) {
 355                /* we didn't find the right inode.. */
 356                iput(inode);
 357                return ERR_PTR(-ESTALE);
 358        }
 359        return inode;
 360}
 361
 362static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 363                int fh_len, int fh_type)
 364{
 365        return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 366                                    ext2_nfs_get_inode);
 367}
 368
 369static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
 370                int fh_len, int fh_type)
 371{
 372        return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 373                                    ext2_nfs_get_inode);
 374}
 375
 376static const struct export_operations ext2_export_ops = {
 377        .fh_to_dentry = ext2_fh_to_dentry,
 378        .fh_to_parent = ext2_fh_to_parent,
 379        .get_parent = ext2_get_parent,
 380};
 381
 382static unsigned long get_sb_block(void **data)
 383{
 384        unsigned long   sb_block;
 385        char            *options = (char *) *data;
 386
 387        if (!options || strncmp(options, "sb=", 3) != 0)
 388                return 1;       /* Default location */
 389        options += 3;
 390        sb_block = simple_strtoul(options, &options, 0);
 391        if (*options && *options != ',') {
 392                printk("EXT2-fs: Invalid sb specification: %s\n",
 393                       (char *) *data);
 394                return 1;
 395        }
 396        if (*options == ',')
 397                options++;
 398        *data = (void *) options;
 399        return sb_block;
 400}
 401
 402enum {
 403        Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
 404        Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
 405        Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
 406        Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
 407        Opt_acl, Opt_noacl, Opt_xip, Opt_dax, Opt_ignore, Opt_err, Opt_quota,
 408        Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
 409};
 410
 411static const match_table_t tokens = {
 412        {Opt_bsd_df, "bsddf"},
 413        {Opt_minix_df, "minixdf"},
 414        {Opt_grpid, "grpid"},
 415        {Opt_grpid, "bsdgroups"},
 416        {Opt_nogrpid, "nogrpid"},
 417        {Opt_nogrpid, "sysvgroups"},
 418        {Opt_resgid, "resgid=%u"},
 419        {Opt_resuid, "resuid=%u"},
 420        {Opt_sb, "sb=%u"},
 421        {Opt_err_cont, "errors=continue"},
 422        {Opt_err_panic, "errors=panic"},
 423        {Opt_err_ro, "errors=remount-ro"},
 424        {Opt_nouid32, "nouid32"},
 425        {Opt_nocheck, "check=none"},
 426        {Opt_nocheck, "nocheck"},
 427        {Opt_debug, "debug"},
 428        {Opt_oldalloc, "oldalloc"},
 429        {Opt_orlov, "orlov"},
 430        {Opt_nobh, "nobh"},
 431        {Opt_user_xattr, "user_xattr"},
 432        {Opt_nouser_xattr, "nouser_xattr"},
 433        {Opt_acl, "acl"},
 434        {Opt_noacl, "noacl"},
 435        {Opt_xip, "xip"},
 436        {Opt_dax, "dax"},
 437        {Opt_grpquota, "grpquota"},
 438        {Opt_ignore, "noquota"},
 439        {Opt_quota, "quota"},
 440        {Opt_usrquota, "usrquota"},
 441        {Opt_reservation, "reservation"},
 442        {Opt_noreservation, "noreservation"},
 443        {Opt_err, NULL}
 444};
 445
 446static int parse_options(char *options, struct super_block *sb)
 447{
 448        char *p;
 449        struct ext2_sb_info *sbi = EXT2_SB(sb);
 450        substring_t args[MAX_OPT_ARGS];
 451        int option;
 452        kuid_t uid;
 453        kgid_t gid;
 454
 455        if (!options)
 456                return 1;
 457
 458        while ((p = strsep (&options, ",")) != NULL) {
 459                int token;
 460                if (!*p)
 461                        continue;
 462
 463                token = match_token(p, tokens, args);
 464                switch (token) {
 465                case Opt_bsd_df:
 466                        clear_opt (sbi->s_mount_opt, MINIX_DF);
 467                        break;
 468                case Opt_minix_df:
 469                        set_opt (sbi->s_mount_opt, MINIX_DF);
 470                        break;
 471                case Opt_grpid:
 472                        set_opt (sbi->s_mount_opt, GRPID);
 473                        break;
 474                case Opt_nogrpid:
 475                        clear_opt (sbi->s_mount_opt, GRPID);
 476                        break;
 477                case Opt_resuid:
 478                        if (match_int(&args[0], &option))
 479                                return 0;
 480                        uid = make_kuid(current_user_ns(), option);
 481                        if (!uid_valid(uid)) {
 482                                ext2_msg(sb, KERN_ERR, "Invalid uid value %d", option);
 483                                return 0;
 484
 485                        }
 486                        sbi->s_resuid = uid;
 487                        break;
 488                case Opt_resgid:
 489                        if (match_int(&args[0], &option))
 490                                return 0;
 491                        gid = make_kgid(current_user_ns(), option);
 492                        if (!gid_valid(gid)) {
 493                                ext2_msg(sb, KERN_ERR, "Invalid gid value %d", option);
 494                                return 0;
 495                        }
 496                        sbi->s_resgid = gid;
 497                        break;
 498                case Opt_sb:
 499                        /* handled by get_sb_block() instead of here */
 500                        /* *sb_block = match_int(&args[0]); */
 501                        break;
 502                case Opt_err_panic:
 503                        clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 504                        clear_opt (sbi->s_mount_opt, ERRORS_RO);
 505                        set_opt (sbi->s_mount_opt, ERRORS_PANIC);
 506                        break;
 507                case Opt_err_ro:
 508                        clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 509                        clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 510                        set_opt (sbi->s_mount_opt, ERRORS_RO);
 511                        break;
 512                case Opt_err_cont:
 513                        clear_opt (sbi->s_mount_opt, ERRORS_RO);
 514                        clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 515                        set_opt (sbi->s_mount_opt, ERRORS_CONT);
 516                        break;
 517                case Opt_nouid32:
 518                        set_opt (sbi->s_mount_opt, NO_UID32);
 519                        break;
 520                case Opt_nocheck:
 521                        clear_opt (sbi->s_mount_opt, CHECK);
 522                        break;
 523                case Opt_debug:
 524                        set_opt (sbi->s_mount_opt, DEBUG);
 525                        break;
 526                case Opt_oldalloc:
 527                        set_opt (sbi->s_mount_opt, OLDALLOC);
 528                        break;
 529                case Opt_orlov:
 530                        clear_opt (sbi->s_mount_opt, OLDALLOC);
 531                        break;
 532                case Opt_nobh:
 533                        set_opt (sbi->s_mount_opt, NOBH);
 534                        break;
 535#ifdef CONFIG_EXT2_FS_XATTR
 536                case Opt_user_xattr:
 537                        set_opt (sbi->s_mount_opt, XATTR_USER);
 538                        break;
 539                case Opt_nouser_xattr:
 540                        clear_opt (sbi->s_mount_opt, XATTR_USER);
 541                        break;
 542#else
 543                case Opt_user_xattr:
 544                case Opt_nouser_xattr:
 545                        ext2_msg(sb, KERN_INFO, "(no)user_xattr options"
 546                                "not supported");
 547                        break;
 548#endif
 549#ifdef CONFIG_EXT2_FS_POSIX_ACL
 550                case Opt_acl:
 551                        set_opt(sbi->s_mount_opt, POSIX_ACL);
 552                        break;
 553                case Opt_noacl:
 554                        clear_opt(sbi->s_mount_opt, POSIX_ACL);
 555                        break;
 556#else
 557                case Opt_acl:
 558                case Opt_noacl:
 559                        ext2_msg(sb, KERN_INFO,
 560                                "(no)acl options not supported");
 561                        break;
 562#endif
 563                case Opt_xip:
 564                        ext2_msg(sb, KERN_INFO, "use dax instead of xip");
 565                        set_opt(sbi->s_mount_opt, XIP);
 566                        /* Fall through */
 567                case Opt_dax:
 568#ifdef CONFIG_FS_DAX
 569                        set_opt(sbi->s_mount_opt, DAX);
 570#else
 571                        ext2_msg(sb, KERN_INFO, "dax option not supported");
 572#endif
 573                        break;
 574
 575#if defined(CONFIG_QUOTA)
 576                case Opt_quota:
 577                case Opt_usrquota:
 578                        set_opt(sbi->s_mount_opt, USRQUOTA);
 579                        break;
 580
 581                case Opt_grpquota:
 582                        set_opt(sbi->s_mount_opt, GRPQUOTA);
 583                        break;
 584#else
 585                case Opt_quota:
 586                case Opt_usrquota:
 587                case Opt_grpquota:
 588                        ext2_msg(sb, KERN_INFO,
 589                                "quota operations not supported");
 590                        break;
 591#endif
 592
 593                case Opt_reservation:
 594                        set_opt(sbi->s_mount_opt, RESERVATION);
 595                        ext2_msg(sb, KERN_INFO, "reservations ON");
 596                        break;
 597                case Opt_noreservation:
 598                        clear_opt(sbi->s_mount_opt, RESERVATION);
 599                        ext2_msg(sb, KERN_INFO, "reservations OFF");
 600                        break;
 601                case Opt_ignore:
 602                        break;
 603                default:
 604                        return 0;
 605                }
 606        }
 607        return 1;
 608}
 609
 610static int ext2_setup_super (struct super_block * sb,
 611                              struct ext2_super_block * es,
 612                              int read_only)
 613{
 614        int res = 0;
 615        struct ext2_sb_info *sbi = EXT2_SB(sb);
 616
 617        if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 618                ext2_msg(sb, KERN_ERR,
 619                        "error: revision level too high, "
 620                        "forcing read-only mode");
 621                res = MS_RDONLY;
 622        }
 623        if (read_only)
 624                return res;
 625        if (!(sbi->s_mount_state & EXT2_VALID_FS))
 626                ext2_msg(sb, KERN_WARNING,
 627                        "warning: mounting unchecked fs, "
 628                        "running e2fsck is recommended");
 629        else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 630                ext2_msg(sb, KERN_WARNING,
 631                        "warning: mounting fs with errors, "
 632                        "running e2fsck is recommended");
 633        else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 634                 le16_to_cpu(es->s_mnt_count) >=
 635                 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 636                ext2_msg(sb, KERN_WARNING,
 637                        "warning: maximal mount count reached, "
 638                        "running e2fsck is recommended");
 639        else if (le32_to_cpu(es->s_checkinterval) &&
 640                (le32_to_cpu(es->s_lastcheck) +
 641                        le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 642                ext2_msg(sb, KERN_WARNING,
 643                        "warning: checktime reached, "
 644                        "running e2fsck is recommended");
 645        if (!le16_to_cpu(es->s_max_mnt_count))
 646                es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 647        le16_add_cpu(&es->s_mnt_count, 1);
 648        if (test_opt (sb, DEBUG))
 649                ext2_msg(sb, KERN_INFO, "%s, %s, bs=%lu, fs=%lu, gc=%lu, "
 650                        "bpg=%lu, ipg=%lu, mo=%04lx]",
 651                        EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 652                        sbi->s_frag_size,
 653                        sbi->s_groups_count,
 654                        EXT2_BLOCKS_PER_GROUP(sb),
 655                        EXT2_INODES_PER_GROUP(sb),
 656                        sbi->s_mount_opt);
 657        return res;
 658}
 659
 660static int ext2_check_descriptors(struct super_block *sb)
 661{
 662        int i;
 663        struct ext2_sb_info *sbi = EXT2_SB(sb);
 664
 665        ext2_debug ("Checking group descriptors");
 666
 667        for (i = 0; i < sbi->s_groups_count; i++) {
 668                struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
 669                ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
 670                ext2_fsblk_t last_block;
 671
 672                if (i == sbi->s_groups_count - 1)
 673                        last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
 674                else
 675                        last_block = first_block +
 676                                (EXT2_BLOCKS_PER_GROUP(sb) - 1);
 677
 678                if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
 679                    le32_to_cpu(gdp->bg_block_bitmap) > last_block)
 680                {
 681                        ext2_error (sb, "ext2_check_descriptors",
 682                                    "Block bitmap for group %d"
 683                                    " not in group (block %lu)!",
 684                                    i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 685                        return 0;
 686                }
 687                if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
 688                    le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
 689                {
 690                        ext2_error (sb, "ext2_check_descriptors",
 691                                    "Inode bitmap for group %d"
 692                                    " not in group (block %lu)!",
 693                                    i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 694                        return 0;
 695                }
 696                if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
 697                    le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
 698                    last_block)
 699                {
 700                        ext2_error (sb, "ext2_check_descriptors",
 701                                    "Inode table for group %d"
 702                                    " not in group (block %lu)!",
 703                                    i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 704                        return 0;
 705                }
 706        }
 707        return 1;
 708}
 709
 710/*
 711 * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 712 * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 713 * We need to be 1 filesystem block less than the 2^32 sector limit.
 714 */
 715static loff_t ext2_max_size(int bits)
 716{
 717        loff_t res = EXT2_NDIR_BLOCKS;
 718        int meta_blocks;
 719        loff_t upper_limit;
 720
 721        /* This is calculated to be the largest file size for a
 722         * dense, file such that the total number of
 723         * sectors in the file, including data and all indirect blocks,
 724         * does not exceed 2^32 -1
 725         * __u32 i_blocks representing the total number of
 726         * 512 bytes blocks of the file
 727         */
 728        upper_limit = (1LL << 32) - 1;
 729
 730        /* total blocks in file system block size */
 731        upper_limit >>= (bits - 9);
 732
 733
 734        /* indirect blocks */
 735        meta_blocks = 1;
 736        /* double indirect blocks */
 737        meta_blocks += 1 + (1LL << (bits-2));
 738        /* tripple indirect blocks */
 739        meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
 740
 741        upper_limit -= meta_blocks;
 742        upper_limit <<= bits;
 743
 744        res += 1LL << (bits-2);
 745        res += 1LL << (2*(bits-2));
 746        res += 1LL << (3*(bits-2));
 747        res <<= bits;
 748        if (res > upper_limit)
 749                res = upper_limit;
 750
 751        if (res > MAX_LFS_FILESIZE)
 752                res = MAX_LFS_FILESIZE;
 753
 754        return res;
 755}
 756
 757static unsigned long descriptor_loc(struct super_block *sb,
 758                                    unsigned long logic_sb_block,
 759                                    int nr)
 760{
 761        struct ext2_sb_info *sbi = EXT2_SB(sb);
 762        unsigned long bg, first_meta_bg;
 763        int has_super = 0;
 764        
 765        first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 766
 767        if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 768            nr < first_meta_bg)
 769                return (logic_sb_block + nr + 1);
 770        bg = sbi->s_desc_per_block * nr;
 771        if (ext2_bg_has_super(sb, bg))
 772                has_super = 1;
 773
 774        return ext2_group_first_block_no(sb, bg) + has_super;
 775}
 776
 777static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 778{
 779        struct buffer_head * bh;
 780        struct ext2_sb_info * sbi;
 781        struct ext2_super_block * es;
 782        struct inode *root;
 783        unsigned long block;
 784        unsigned long sb_block = get_sb_block(&data);
 785        unsigned long logic_sb_block;
 786        unsigned long offset = 0;
 787        unsigned long def_mount_opts;
 788        long ret = -EINVAL;
 789        int blocksize = BLOCK_SIZE;
 790        int db_count;
 791        int i, j;
 792        __le32 features;
 793        int err;
 794
 795        err = -ENOMEM;
 796        sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 797        if (!sbi)
 798                goto failed;
 799
 800        sbi->s_blockgroup_lock =
 801                kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
 802        if (!sbi->s_blockgroup_lock) {
 803                kfree(sbi);
 804                goto failed;
 805        }
 806        sb->s_fs_info = sbi;
 807        sbi->s_sb_block = sb_block;
 808
 809        spin_lock_init(&sbi->s_lock);
 810
 811        /*
 812         * See what the current blocksize for the device is, and
 813         * use that as the blocksize.  Otherwise (or if the blocksize
 814         * is smaller than the default) use the default.
 815         * This is important for devices that have a hardware
 816         * sectorsize that is larger than the default.
 817         */
 818        blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 819        if (!blocksize) {
 820                ext2_msg(sb, KERN_ERR, "error: unable to set blocksize");
 821                goto failed_sbi;
 822        }
 823
 824        /*
 825         * If the superblock doesn't start on a hardware sector boundary,
 826         * calculate the offset.  
 827         */
 828        if (blocksize != BLOCK_SIZE) {
 829                logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 830                offset = (sb_block*BLOCK_SIZE) % blocksize;
 831        } else {
 832                logic_sb_block = sb_block;
 833        }
 834
 835        if (!(bh = sb_bread(sb, logic_sb_block))) {
 836                ext2_msg(sb, KERN_ERR, "error: unable to read superblock");
 837                goto failed_sbi;
 838        }
 839        /*
 840         * Note: s_es must be initialized as soon as possible because
 841         *       some ext2 macro-instructions depend on its value
 842         */
 843        es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 844        sbi->s_es = es;
 845        sb->s_magic = le16_to_cpu(es->s_magic);
 846
 847        if (sb->s_magic != EXT2_SUPER_MAGIC)
 848                goto cantfind_ext2;
 849
 850        /* Set defaults before we parse the mount options */
 851        def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 852        if (def_mount_opts & EXT2_DEFM_DEBUG)
 853                set_opt(sbi->s_mount_opt, DEBUG);
 854        if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 855                set_opt(sbi->s_mount_opt, GRPID);
 856        if (def_mount_opts & EXT2_DEFM_UID16)
 857                set_opt(sbi->s_mount_opt, NO_UID32);
 858#ifdef CONFIG_EXT2_FS_XATTR
 859        if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 860                set_opt(sbi->s_mount_opt, XATTR_USER);
 861#endif
 862#ifdef CONFIG_EXT2_FS_POSIX_ACL
 863        if (def_mount_opts & EXT2_DEFM_ACL)
 864                set_opt(sbi->s_mount_opt, POSIX_ACL);
 865#endif
 866        
 867        if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 868                set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 869        else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
 870                set_opt(sbi->s_mount_opt, ERRORS_CONT);
 871        else
 872                set_opt(sbi->s_mount_opt, ERRORS_RO);
 873
 874        sbi->s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
 875        sbi->s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
 876        
 877        set_opt(sbi->s_mount_opt, RESERVATION);
 878
 879        if (!parse_options((char *) data, sb))
 880                goto failed_mount;
 881
 882        sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 883                ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 884                 MS_POSIXACL : 0);
 885        sb->s_iflags |= SB_I_CGROUPWB;
 886
 887        if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 888            (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 889             EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 890             EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 891                ext2_msg(sb, KERN_WARNING,
 892                        "warning: feature flags set on rev 0 fs, "
 893                        "running e2fsck is recommended");
 894        /*
 895         * Check feature flags regardless of the revision level, since we
 896         * previously didn't change the revision level when setting the flags,
 897         * so there is a chance incompat flags are set on a rev 0 filesystem.
 898         */
 899        features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 900        if (features) {
 901                ext2_msg(sb, KERN_ERR,  "error: couldn't mount because of "
 902                       "unsupported optional features (%x)",
 903                        le32_to_cpu(features));
 904                goto failed_mount;
 905        }
 906        if (!(sb->s_flags & MS_RDONLY) &&
 907            (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 908                ext2_msg(sb, KERN_ERR, "error: couldn't mount RDWR because of "
 909                       "unsupported optional features (%x)",
 910                       le32_to_cpu(features));
 911                goto failed_mount;
 912        }
 913
 914        blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 915
 916        if (sbi->s_mount_opt & EXT2_MOUNT_DAX) {
 917                if (blocksize != PAGE_SIZE) {
 918                        ext2_msg(sb, KERN_ERR,
 919                                        "error: unsupported blocksize for dax");
 920                        goto failed_mount;
 921                }
 922                if (!sb->s_bdev->bd_disk->fops->direct_access) {
 923                        ext2_msg(sb, KERN_ERR,
 924                                        "error: device does not support dax");
 925                        goto failed_mount;
 926                }
 927        }
 928
 929        /* If the blocksize doesn't match, re-read the thing.. */
 930        if (sb->s_blocksize != blocksize) {
 931                brelse(bh);
 932
 933                if (!sb_set_blocksize(sb, blocksize)) {
 934                        ext2_msg(sb, KERN_ERR,
 935                                "error: bad blocksize %d", blocksize);
 936                        goto failed_sbi;
 937                }
 938
 939                logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 940                offset = (sb_block*BLOCK_SIZE) % blocksize;
 941                bh = sb_bread(sb, logic_sb_block);
 942                if(!bh) {
 943                        ext2_msg(sb, KERN_ERR, "error: couldn't read"
 944                                "superblock on 2nd try");
 945                        goto failed_sbi;
 946                }
 947                es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 948                sbi->s_es = es;
 949                if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 950                        ext2_msg(sb, KERN_ERR, "error: magic mismatch");
 951                        goto failed_mount;
 952                }
 953        }
 954
 955        sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 956        sb->s_max_links = EXT2_LINK_MAX;
 957
 958        if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 959                sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 960                sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 961        } else {
 962                sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 963                sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 964                if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 965                    !is_power_of_2(sbi->s_inode_size) ||
 966                    (sbi->s_inode_size > blocksize)) {
 967                        ext2_msg(sb, KERN_ERR,
 968                                "error: unsupported inode size: %d",
 969                                sbi->s_inode_size);
 970                        goto failed_mount;
 971                }
 972        }
 973
 974        sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 975                                   le32_to_cpu(es->s_log_frag_size);
 976        if (sbi->s_frag_size == 0)
 977                goto cantfind_ext2;
 978        sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
 979
 980        sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 981        sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 982        sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 983
 984        if (EXT2_INODE_SIZE(sb) == 0)
 985                goto cantfind_ext2;
 986        sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
 987        if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
 988                goto cantfind_ext2;
 989        sbi->s_itb_per_group = sbi->s_inodes_per_group /
 990                                        sbi->s_inodes_per_block;
 991        sbi->s_desc_per_block = sb->s_blocksize /
 992                                        sizeof (struct ext2_group_desc);
 993        sbi->s_sbh = bh;
 994        sbi->s_mount_state = le16_to_cpu(es->s_state);
 995        sbi->s_addr_per_block_bits =
 996                ilog2 (EXT2_ADDR_PER_BLOCK(sb));
 997        sbi->s_desc_per_block_bits =
 998                ilog2 (EXT2_DESC_PER_BLOCK(sb));
 999
1000        if (sb->s_magic != EXT2_SUPER_MAGIC)
1001                goto cantfind_ext2;
1002
1003        if (sb->s_blocksize != bh->b_size) {
1004                if (!silent)
1005                        ext2_msg(sb, KERN_ERR, "error: unsupported blocksize");
1006                goto failed_mount;
1007        }
1008
1009        if (sb->s_blocksize != sbi->s_frag_size) {
1010                ext2_msg(sb, KERN_ERR,
1011                        "error: fragsize %lu != blocksize %lu"
1012                        "(not supported yet)",
1013                        sbi->s_frag_size, sb->s_blocksize);
1014                goto failed_mount;
1015        }
1016
1017        if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
1018                ext2_msg(sb, KERN_ERR,
1019                        "error: #blocks per group too big: %lu",
1020                        sbi->s_blocks_per_group);
1021                goto failed_mount;
1022        }
1023        if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
1024                ext2_msg(sb, KERN_ERR,
1025                        "error: #fragments per group too big: %lu",
1026                        sbi->s_frags_per_group);
1027                goto failed_mount;
1028        }
1029        if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
1030                ext2_msg(sb, KERN_ERR,
1031                        "error: #inodes per group too big: %lu",
1032                        sbi->s_inodes_per_group);
1033                goto failed_mount;
1034        }
1035
1036        if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
1037                goto cantfind_ext2;
1038        sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
1039                                le32_to_cpu(es->s_first_data_block) - 1)
1040                                        / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
1041        db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
1042                   EXT2_DESC_PER_BLOCK(sb);
1043        sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
1044        if (sbi->s_group_desc == NULL) {
1045                ext2_msg(sb, KERN_ERR, "error: not enough memory");
1046                goto failed_mount;
1047        }
1048        bgl_lock_init(sbi->s_blockgroup_lock);
1049        sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
1050        if (!sbi->s_debts) {
1051                ext2_msg(sb, KERN_ERR, "error: not enough memory");
1052                goto failed_mount_group_desc;
1053        }
1054        for (i = 0; i < db_count; i++) {
1055                block = descriptor_loc(sb, logic_sb_block, i);
1056                sbi->s_group_desc[i] = sb_bread(sb, block);
1057                if (!sbi->s_group_desc[i]) {
1058                        for (j = 0; j < i; j++)
1059                                brelse (sbi->s_group_desc[j]);
1060                        ext2_msg(sb, KERN_ERR,
1061                                "error: unable to read group descriptors");
1062                        goto failed_mount_group_desc;
1063                }
1064        }
1065        if (!ext2_check_descriptors (sb)) {
1066                ext2_msg(sb, KERN_ERR, "group descriptors corrupted");
1067                goto failed_mount2;
1068        }
1069        sbi->s_gdb_count = db_count;
1070        get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1071        spin_lock_init(&sbi->s_next_gen_lock);
1072
1073        /* per fileystem reservation list head & lock */
1074        spin_lock_init(&sbi->s_rsv_window_lock);
1075        sbi->s_rsv_window_root = RB_ROOT;
1076        /*
1077         * Add a single, static dummy reservation to the start of the
1078         * reservation window list --- it gives us a placeholder for
1079         * append-at-start-of-list which makes the allocation logic
1080         * _much_ simpler.
1081         */
1082        sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1083        sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1084        sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1085        sbi->s_rsv_window_head.rsv_goal_size = 0;
1086        ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1087
1088        err = percpu_counter_init(&sbi->s_freeblocks_counter,
1089                                ext2_count_free_blocks(sb), GFP_KERNEL);
1090        if (!err) {
1091                err = percpu_counter_init(&sbi->s_freeinodes_counter,
1092                                ext2_count_free_inodes(sb), GFP_KERNEL);
1093        }
1094        if (!err) {
1095                err = percpu_counter_init(&sbi->s_dirs_counter,
1096                                ext2_count_dirs(sb), GFP_KERNEL);
1097        }
1098        if (err) {
1099                ext2_msg(sb, KERN_ERR, "error: insufficient memory");
1100                goto failed_mount3;
1101        }
1102        /*
1103         * set up enough so that it can read an inode
1104         */
1105        sb->s_op = &ext2_sops;
1106        sb->s_export_op = &ext2_export_ops;
1107        sb->s_xattr = ext2_xattr_handlers;
1108
1109#ifdef CONFIG_QUOTA
1110        sb->dq_op = &dquot_operations;
1111        sb->s_qcop = &dquot_quotactl_ops;
1112        sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP;
1113#endif
1114
1115        root = ext2_iget(sb, EXT2_ROOT_INO);
1116        if (IS_ERR(root)) {
1117                ret = PTR_ERR(root);
1118                goto failed_mount3;
1119        }
1120        if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1121                iput(root);
1122                ext2_msg(sb, KERN_ERR, "error: corrupt root inode, run e2fsck");
1123                goto failed_mount3;
1124        }
1125
1126        sb->s_root = d_make_root(root);
1127        if (!sb->s_root) {
1128                ext2_msg(sb, KERN_ERR, "error: get root inode failed");
1129                ret = -ENOMEM;
1130                goto failed_mount3;
1131        }
1132        if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1133                ext2_msg(sb, KERN_WARNING,
1134                        "warning: mounting ext3 filesystem as ext2");
1135        if (ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY))
1136                sb->s_flags |= MS_RDONLY;
1137        ext2_write_super(sb);
1138        return 0;
1139
1140cantfind_ext2:
1141        if (!silent)
1142                ext2_msg(sb, KERN_ERR,
1143                        "error: can't find an ext2 filesystem on dev %s.",
1144                        sb->s_id);
1145        goto failed_mount;
1146failed_mount3:
1147        percpu_counter_destroy(&sbi->s_freeblocks_counter);
1148        percpu_counter_destroy(&sbi->s_freeinodes_counter);
1149        percpu_counter_destroy(&sbi->s_dirs_counter);
1150failed_mount2:
1151        for (i = 0; i < db_count; i++)
1152                brelse(sbi->s_group_desc[i]);
1153failed_mount_group_desc:
1154        kfree(sbi->s_group_desc);
1155        kfree(sbi->s_debts);
1156failed_mount:
1157        brelse(bh);
1158failed_sbi:
1159        sb->s_fs_info = NULL;
1160        kfree(sbi->s_blockgroup_lock);
1161        kfree(sbi);
1162failed:
1163        return ret;
1164}
1165
1166static void ext2_clear_super_error(struct super_block *sb)
1167{
1168        struct buffer_head *sbh = EXT2_SB(sb)->s_sbh;
1169
1170        if (buffer_write_io_error(sbh)) {
1171                /*
1172                 * Oh, dear.  A previous attempt to write the
1173                 * superblock failed.  This could happen because the
1174                 * USB device was yanked out.  Or it could happen to
1175                 * be a transient write error and maybe the block will
1176                 * be remapped.  Nothing we can do but to retry the
1177                 * write and hope for the best.
1178                 */
1179                ext2_msg(sb, KERN_ERR,
1180                       "previous I/O error to superblock detected\n");
1181                clear_buffer_write_io_error(sbh);
1182                set_buffer_uptodate(sbh);
1183        }
1184}
1185
1186static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
1187                            int wait)
1188{
1189        ext2_clear_super_error(sb);
1190        spin_lock(&EXT2_SB(sb)->s_lock);
1191        es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1192        es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1193        es->s_wtime = cpu_to_le32(get_seconds());
1194        /* unlock before we do IO */
1195        spin_unlock(&EXT2_SB(sb)->s_lock);
1196        mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1197        if (wait)
1198                sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1199}
1200
1201/*
1202 * In the second extended file system, it is not necessary to
1203 * write the super block since we use a mapping of the
1204 * disk super block in a buffer.
1205 *
1206 * However, this function is still used to set the fs valid
1207 * flags to 0.  We need to set this flag to 0 since the fs
1208 * may have been checked while mounted and e2fsck may have
1209 * set s_state to EXT2_VALID_FS after some corrections.
1210 */
1211static int ext2_sync_fs(struct super_block *sb, int wait)
1212{
1213        struct ext2_sb_info *sbi = EXT2_SB(sb);
1214        struct ext2_super_block *es = EXT2_SB(sb)->s_es;
1215
1216        /*
1217         * Write quota structures to quota file, sync_blockdev() will write
1218         * them to disk later
1219         */
1220        dquot_writeback_dquots(sb, -1);
1221
1222        spin_lock(&sbi->s_lock);
1223        if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1224                ext2_debug("setting valid to 0\n");
1225                es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1226        }
1227        spin_unlock(&sbi->s_lock);
1228        ext2_sync_super(sb, es, wait);
1229        return 0;
1230}
1231
1232static int ext2_freeze(struct super_block *sb)
1233{
1234        struct ext2_sb_info *sbi = EXT2_SB(sb);
1235
1236        /*
1237         * Open but unlinked files present? Keep EXT2_VALID_FS flag cleared
1238         * because we have unattached inodes and thus filesystem is not fully
1239         * consistent.
1240         */
1241        if (atomic_long_read(&sb->s_remove_count)) {
1242                ext2_sync_fs(sb, 1);
1243                return 0;
1244        }
1245        /* Set EXT2_FS_VALID flag */
1246        spin_lock(&sbi->s_lock);
1247        sbi->s_es->s_state = cpu_to_le16(sbi->s_mount_state);
1248        spin_unlock(&sbi->s_lock);
1249        ext2_sync_super(sb, sbi->s_es, 1);
1250
1251        return 0;
1252}
1253
1254static int ext2_unfreeze(struct super_block *sb)
1255{
1256        /* Just write sb to clear EXT2_VALID_FS flag */
1257        ext2_write_super(sb);
1258
1259        return 0;
1260}
1261
1262void ext2_write_super(struct super_block *sb)
1263{
1264        if (!(sb->s_flags & MS_RDONLY))
1265                ext2_sync_fs(sb, 1);
1266}
1267
1268static int ext2_remount (struct super_block * sb, int * flags, char * data)
1269{
1270        struct ext2_sb_info * sbi = EXT2_SB(sb);
1271        struct ext2_super_block * es;
1272        struct ext2_mount_options old_opts;
1273        unsigned long old_sb_flags;
1274        int err;
1275
1276        sync_filesystem(sb);
1277        spin_lock(&sbi->s_lock);
1278
1279        /* Store the old options */
1280        old_sb_flags = sb->s_flags;
1281        old_opts.s_mount_opt = sbi->s_mount_opt;
1282        old_opts.s_resuid = sbi->s_resuid;
1283        old_opts.s_resgid = sbi->s_resgid;
1284
1285        /*
1286         * Allow the "check" option to be passed as a remount option.
1287         */
1288        if (!parse_options(data, sb)) {
1289                err = -EINVAL;
1290                goto restore_opts;
1291        }
1292
1293        sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1294                ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1295
1296        es = sbi->s_es;
1297        if ((sbi->s_mount_opt ^ old_opts.s_mount_opt) & EXT2_MOUNT_DAX) {
1298                ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
1299                         "dax flag with busy inodes while remounting");
1300                sbi->s_mount_opt ^= EXT2_MOUNT_DAX;
1301        }
1302        if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
1303                spin_unlock(&sbi->s_lock);
1304                return 0;
1305        }
1306        if (*flags & MS_RDONLY) {
1307                if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1308                    !(sbi->s_mount_state & EXT2_VALID_FS)) {
1309                        spin_unlock(&sbi->s_lock);
1310                        return 0;
1311                }
1312
1313                /*
1314                 * OK, we are remounting a valid rw partition rdonly, so set
1315                 * the rdonly flag and then mark the partition as valid again.
1316                 */
1317                es->s_state = cpu_to_le16(sbi->s_mount_state);
1318                es->s_mtime = cpu_to_le32(get_seconds());
1319                spin_unlock(&sbi->s_lock);
1320
1321                err = dquot_suspend(sb, -1);
1322                if (err < 0) {
1323                        spin_lock(&sbi->s_lock);
1324                        goto restore_opts;
1325                }
1326
1327                ext2_sync_super(sb, es, 1);
1328        } else {
1329                __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1330                                               ~EXT2_FEATURE_RO_COMPAT_SUPP);
1331                if (ret) {
1332                        ext2_msg(sb, KERN_WARNING,
1333                                "warning: couldn't remount RDWR because of "
1334                                "unsupported optional features (%x).",
1335                                le32_to_cpu(ret));
1336                        err = -EROFS;
1337                        goto restore_opts;
1338                }
1339                /*
1340                 * Mounting a RDONLY partition read-write, so reread and
1341                 * store the current valid flag.  (It may have been changed
1342                 * by e2fsck since we originally mounted the partition.)
1343                 */
1344                sbi->s_mount_state = le16_to_cpu(es->s_state);
1345                if (!ext2_setup_super (sb, es, 0))
1346                        sb->s_flags &= ~MS_RDONLY;
1347                spin_unlock(&sbi->s_lock);
1348
1349                ext2_write_super(sb);
1350
1351                dquot_resume(sb, -1);
1352        }
1353
1354        return 0;
1355restore_opts:
1356        sbi->s_mount_opt = old_opts.s_mount_opt;
1357        sbi->s_resuid = old_opts.s_resuid;
1358        sbi->s_resgid = old_opts.s_resgid;
1359        sb->s_flags = old_sb_flags;
1360        spin_unlock(&sbi->s_lock);
1361        return err;
1362}
1363
1364static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1365{
1366        struct super_block *sb = dentry->d_sb;
1367        struct ext2_sb_info *sbi = EXT2_SB(sb);
1368        struct ext2_super_block *es = sbi->s_es;
1369        u64 fsid;
1370
1371        spin_lock(&sbi->s_lock);
1372
1373        if (test_opt (sb, MINIX_DF))
1374                sbi->s_overhead_last = 0;
1375        else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1376                unsigned long i, overhead = 0;
1377                smp_rmb();
1378
1379                /*
1380                 * Compute the overhead (FS structures). This is constant
1381                 * for a given filesystem unless the number of block groups
1382                 * changes so we cache the previous value until it does.
1383                 */
1384
1385                /*
1386                 * All of the blocks before first_data_block are
1387                 * overhead
1388                 */
1389                overhead = le32_to_cpu(es->s_first_data_block);
1390
1391                /*
1392                 * Add the overhead attributed to the superblock and
1393                 * block group descriptors.  If the sparse superblocks
1394                 * feature is turned on, then not all groups have this.
1395                 */
1396                for (i = 0; i < sbi->s_groups_count; i++)
1397                        overhead += ext2_bg_has_super(sb, i) +
1398                                ext2_bg_num_gdb(sb, i);
1399
1400                /*
1401                 * Every block group has an inode bitmap, a block
1402                 * bitmap, and an inode table.
1403                 */
1404                overhead += (sbi->s_groups_count *
1405                             (2 + sbi->s_itb_per_group));
1406                sbi->s_overhead_last = overhead;
1407                smp_wmb();
1408                sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1409        }
1410
1411        buf->f_type = EXT2_SUPER_MAGIC;
1412        buf->f_bsize = sb->s_blocksize;
1413        buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1414        buf->f_bfree = ext2_count_free_blocks(sb);
1415        es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1416        buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1417        if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1418                buf->f_bavail = 0;
1419        buf->f_files = le32_to_cpu(es->s_inodes_count);
1420        buf->f_ffree = ext2_count_free_inodes(sb);
1421        es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1422        buf->f_namelen = EXT2_NAME_LEN;
1423        fsid = le64_to_cpup((void *)es->s_uuid) ^
1424               le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1425        buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1426        buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1427        spin_unlock(&sbi->s_lock);
1428        return 0;
1429}
1430
1431static struct dentry *ext2_mount(struct file_system_type *fs_type,
1432        int flags, const char *dev_name, void *data)
1433{
1434        return mount_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1435}
1436
1437#ifdef CONFIG_QUOTA
1438
1439/* Read data from quotafile - avoid pagecache and such because we cannot afford
1440 * acquiring the locks... As quota files are never truncated and quota code
1441 * itself serializes the operations (and no one else should touch the files)
1442 * we don't have to be afraid of races */
1443static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1444                               size_t len, loff_t off)
1445{
1446        struct inode *inode = sb_dqopt(sb)->files[type];
1447        sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1448        int err = 0;
1449        int offset = off & (sb->s_blocksize - 1);
1450        int tocopy;
1451        size_t toread;
1452        struct buffer_head tmp_bh;
1453        struct buffer_head *bh;
1454        loff_t i_size = i_size_read(inode);
1455
1456        if (off > i_size)
1457                return 0;
1458        if (off+len > i_size)
1459                len = i_size-off;
1460        toread = len;
1461        while (toread > 0) {
1462                tocopy = sb->s_blocksize - offset < toread ?
1463                                sb->s_blocksize - offset : toread;
1464
1465                tmp_bh.b_state = 0;
1466                tmp_bh.b_size = sb->s_blocksize;
1467                err = ext2_get_block(inode, blk, &tmp_bh, 0);
1468                if (err < 0)
1469                        return err;
1470                if (!buffer_mapped(&tmp_bh))    /* A hole? */
1471                        memset(data, 0, tocopy);
1472                else {
1473                        bh = sb_bread(sb, tmp_bh.b_blocknr);
1474                        if (!bh)
1475                                return -EIO;
1476                        memcpy(data, bh->b_data+offset, tocopy);
1477                        brelse(bh);
1478                }
1479                offset = 0;
1480                toread -= tocopy;
1481                data += tocopy;
1482                blk++;
1483        }
1484        return len;
1485}
1486
1487/* Write to quotafile */
1488static ssize_t ext2_quota_write(struct super_block *sb, int type,
1489                                const char *data, size_t len, loff_t off)
1490{
1491        struct inode *inode = sb_dqopt(sb)->files[type];
1492        sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1493        int err = 0;
1494        int offset = off & (sb->s_blocksize - 1);
1495        int tocopy;
1496        size_t towrite = len;
1497        struct buffer_head tmp_bh;
1498        struct buffer_head *bh;
1499
1500        while (towrite > 0) {
1501                tocopy = sb->s_blocksize - offset < towrite ?
1502                                sb->s_blocksize - offset : towrite;
1503
1504                tmp_bh.b_state = 0;
1505                tmp_bh.b_size = sb->s_blocksize;
1506                err = ext2_get_block(inode, blk, &tmp_bh, 1);
1507                if (err < 0)
1508                        goto out;
1509                if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1510                        bh = sb_bread(sb, tmp_bh.b_blocknr);
1511                else
1512                        bh = sb_getblk(sb, tmp_bh.b_blocknr);
1513                if (unlikely(!bh)) {
1514                        err = -EIO;
1515                        goto out;
1516                }
1517                lock_buffer(bh);
1518                memcpy(bh->b_data+offset, data, tocopy);
1519                flush_dcache_page(bh->b_page);
1520                set_buffer_uptodate(bh);
1521                mark_buffer_dirty(bh);
1522                unlock_buffer(bh);
1523                brelse(bh);
1524                offset = 0;
1525                towrite -= tocopy;
1526                data += tocopy;
1527                blk++;
1528        }
1529out:
1530        if (len == towrite)
1531                return err;
1532        if (inode->i_size < off+len-towrite)
1533                i_size_write(inode, off+len-towrite);
1534        inode->i_version++;
1535        inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1536        mark_inode_dirty(inode);
1537        return len - towrite;
1538}
1539
1540#endif
1541
1542static struct file_system_type ext2_fs_type = {
1543        .owner          = THIS_MODULE,
1544        .name           = "ext2",
1545        .mount          = ext2_mount,
1546        .kill_sb        = kill_block_super,
1547        .fs_flags       = FS_REQUIRES_DEV,
1548};
1549MODULE_ALIAS_FS("ext2");
1550
1551static int __init init_ext2_fs(void)
1552{
1553        int err = init_ext2_xattr();
1554        if (err)
1555                return err;
1556        err = init_inodecache();
1557        if (err)
1558                goto out1;
1559        err = register_filesystem(&ext2_fs_type);
1560        if (err)
1561                goto out;
1562        return 0;
1563out:
1564        destroy_inodecache();
1565out1:
1566        exit_ext2_xattr();
1567        return err;
1568}
1569
1570static void __exit exit_ext2_fs(void)
1571{
1572        unregister_filesystem(&ext2_fs_type);
1573        destroy_inodecache();
1574        exit_ext2_xattr();
1575}
1576
1577MODULE_AUTHOR("Remy Card and others");
1578MODULE_DESCRIPTION("Second Extended Filesystem");
1579MODULE_LICENSE("GPL");
1580module_init(init_ext2_fs)
1581module_exit(exit_ext2_fs)
1582