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 <linux/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        if (sbi->s_mb_cache) {
 135                ext2_xattr_destroy_cache(sbi->s_mb_cache);
 136                sbi->s_mb_cache = NULL;
 137        }
 138        if (!(sb->s_flags & MS_RDONLY)) {
 139                struct ext2_super_block *es = sbi->s_es;
 140
 141                spin_lock(&sbi->s_lock);
 142                es->s_state = cpu_to_le16(sbi->s_mount_state);
 143                spin_unlock(&sbi->s_lock);
 144                ext2_sync_super(sb, es, 1);
 145        }
 146        db_count = sbi->s_gdb_count;
 147        for (i = 0; i < db_count; i++)
 148                if (sbi->s_group_desc[i])
 149                        brelse (sbi->s_group_desc[i]);
 150        kfree(sbi->s_group_desc);
 151        kfree(sbi->s_debts);
 152        percpu_counter_destroy(&sbi->s_freeblocks_counter);
 153        percpu_counter_destroy(&sbi->s_freeinodes_counter);
 154        percpu_counter_destroy(&sbi->s_dirs_counter);
 155        brelse (sbi->s_sbh);
 156        sb->s_fs_info = NULL;
 157        kfree(sbi->s_blockgroup_lock);
 158        kfree(sbi);
 159}
 160
 161static struct kmem_cache * ext2_inode_cachep;
 162
 163static struct inode *ext2_alloc_inode(struct super_block *sb)
 164{
 165        struct ext2_inode_info *ei;
 166        ei = kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
 167        if (!ei)
 168                return NULL;
 169        ei->i_block_alloc_info = NULL;
 170        ei->vfs_inode.i_version = 1;
 171#ifdef CONFIG_QUOTA
 172        memset(&ei->i_dquot, 0, sizeof(ei->i_dquot));
 173#endif
 174
 175        return &ei->vfs_inode;
 176}
 177
 178static void ext2_i_callback(struct rcu_head *head)
 179{
 180        struct inode *inode = container_of(head, struct inode, i_rcu);
 181        kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
 182}
 183
 184static void ext2_destroy_inode(struct inode *inode)
 185{
 186        call_rcu(&inode->i_rcu, ext2_i_callback);
 187}
 188
 189static void init_once(void *foo)
 190{
 191        struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
 192
 193        rwlock_init(&ei->i_meta_lock);
 194#ifdef CONFIG_EXT2_FS_XATTR
 195        init_rwsem(&ei->xattr_sem);
 196#endif
 197        mutex_init(&ei->truncate_mutex);
 198#ifdef CONFIG_FS_DAX
 199        init_rwsem(&ei->dax_sem);
 200#endif
 201        inode_init_once(&ei->vfs_inode);
 202}
 203
 204static int __init init_inodecache(void)
 205{
 206        ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
 207                                             sizeof(struct ext2_inode_info),
 208                                             0, (SLAB_RECLAIM_ACCOUNT|
 209                                                SLAB_MEM_SPREAD|SLAB_ACCOUNT),
 210                                             init_once);
 211        if (ext2_inode_cachep == NULL)
 212                return -ENOMEM;
 213        return 0;
 214}
 215
 216static void destroy_inodecache(void)
 217{
 218        /*
 219         * Make sure all delayed rcu free inodes are flushed before we
 220         * destroy cache.
 221         */
 222        rcu_barrier();
 223        kmem_cache_destroy(ext2_inode_cachep);
 224}
 225
 226static int ext2_show_options(struct seq_file *seq, struct dentry *root)
 227{
 228        struct super_block *sb = root->d_sb;
 229        struct ext2_sb_info *sbi = EXT2_SB(sb);
 230        struct ext2_super_block *es = sbi->s_es;
 231        unsigned long def_mount_opts;
 232
 233        spin_lock(&sbi->s_lock);
 234        def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 235
 236        if (sbi->s_sb_block != 1)
 237                seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
 238        if (test_opt(sb, MINIX_DF))
 239                seq_puts(seq, ",minixdf");
 240        if (test_opt(sb, GRPID))
 241                seq_puts(seq, ",grpid");
 242        if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
 243                seq_puts(seq, ",nogrpid");
 244        if (!uid_eq(sbi->s_resuid, make_kuid(&init_user_ns, EXT2_DEF_RESUID)) ||
 245            le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
 246                seq_printf(seq, ",resuid=%u",
 247                                from_kuid_munged(&init_user_ns, sbi->s_resuid));
 248        }
 249        if (!gid_eq(sbi->s_resgid, make_kgid(&init_user_ns, EXT2_DEF_RESGID)) ||
 250            le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
 251                seq_printf(seq, ",resgid=%u",
 252                                from_kgid_munged(&init_user_ns, sbi->s_resgid));
 253        }
 254        if (test_opt(sb, ERRORS_RO)) {
 255                int def_errors = le16_to_cpu(es->s_errors);
 256
 257                if (def_errors == EXT2_ERRORS_PANIC ||
 258                    def_errors == EXT2_ERRORS_CONTINUE) {
 259                        seq_puts(seq, ",errors=remount-ro");
 260                }
 261        }
 262        if (test_opt(sb, ERRORS_CONT))
 263                seq_puts(seq, ",errors=continue");
 264        if (test_opt(sb, ERRORS_PANIC))
 265                seq_puts(seq, ",errors=panic");
 266        if (test_opt(sb, NO_UID32))
 267                seq_puts(seq, ",nouid32");
 268        if (test_opt(sb, DEBUG))
 269                seq_puts(seq, ",debug");
 270        if (test_opt(sb, OLDALLOC))
 271                seq_puts(seq, ",oldalloc");
 272
 273#ifdef CONFIG_EXT2_FS_XATTR
 274        if (test_opt(sb, XATTR_USER))
 275                seq_puts(seq, ",user_xattr");
 276        if (!test_opt(sb, XATTR_USER) &&
 277            (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
 278                seq_puts(seq, ",nouser_xattr");
 279        }
 280#endif
 281
 282#ifdef CONFIG_EXT2_FS_POSIX_ACL
 283        if (test_opt(sb, POSIX_ACL))
 284                seq_puts(seq, ",acl");
 285        if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
 286                seq_puts(seq, ",noacl");
 287#endif
 288
 289        if (test_opt(sb, NOBH))
 290                seq_puts(seq, ",nobh");
 291
 292#if defined(CONFIG_QUOTA)
 293        if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
 294                seq_puts(seq, ",usrquota");
 295
 296        if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
 297                seq_puts(seq, ",grpquota");
 298#endif
 299
 300#ifdef CONFIG_FS_DAX
 301        if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
 302                seq_puts(seq, ",xip");
 303        if (sbi->s_mount_opt & EXT2_MOUNT_DAX)
 304                seq_puts(seq, ",dax");
 305#endif
 306
 307        if (!test_opt(sb, RESERVATION))
 308                seq_puts(seq, ",noreservation");
 309
 310        spin_unlock(&sbi->s_lock);
 311        return 0;
 312}
 313
 314#ifdef CONFIG_QUOTA
 315static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
 316static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
 317static struct dquot **ext2_get_dquots(struct inode *inode)
 318{
 319        return EXT2_I(inode)->i_dquot;
 320}
 321#endif
 322
 323static const struct super_operations ext2_sops = {
 324        .alloc_inode    = ext2_alloc_inode,
 325        .destroy_inode  = ext2_destroy_inode,
 326        .write_inode    = ext2_write_inode,
 327        .evict_inode    = ext2_evict_inode,
 328        .put_super      = ext2_put_super,
 329        .sync_fs        = ext2_sync_fs,
 330        .freeze_fs      = ext2_freeze,
 331        .unfreeze_fs    = ext2_unfreeze,
 332        .statfs         = ext2_statfs,
 333        .remount_fs     = ext2_remount,
 334        .show_options   = ext2_show_options,
 335#ifdef CONFIG_QUOTA
 336        .quota_read     = ext2_quota_read,
 337        .quota_write    = ext2_quota_write,
 338        .get_dquots     = ext2_get_dquots,
 339#endif
 340};
 341
 342static struct inode *ext2_nfs_get_inode(struct super_block *sb,
 343                u64 ino, u32 generation)
 344{
 345        struct inode *inode;
 346
 347        if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
 348                return ERR_PTR(-ESTALE);
 349        if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
 350                return ERR_PTR(-ESTALE);
 351
 352        /*
 353         * ext2_iget isn't quite right if the inode is currently unallocated!
 354         * However ext2_iget currently does appropriate checks to handle stale
 355         * inodes so everything is OK.
 356         */
 357        inode = ext2_iget(sb, ino);
 358        if (IS_ERR(inode))
 359                return ERR_CAST(inode);
 360        if (generation && inode->i_generation != generation) {
 361                /* we didn't find the right inode.. */
 362                iput(inode);
 363                return ERR_PTR(-ESTALE);
 364        }
 365        return inode;
 366}
 367
 368static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 369                int fh_len, int fh_type)
 370{
 371        return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 372                                    ext2_nfs_get_inode);
 373}
 374
 375static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
 376                int fh_len, int fh_type)
 377{
 378        return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 379                                    ext2_nfs_get_inode);
 380}
 381
 382static const struct export_operations ext2_export_ops = {
 383        .fh_to_dentry = ext2_fh_to_dentry,
 384        .fh_to_parent = ext2_fh_to_parent,
 385        .get_parent = ext2_get_parent,
 386};
 387
 388static unsigned long get_sb_block(void **data)
 389{
 390        unsigned long   sb_block;
 391        char            *options = (char *) *data;
 392
 393        if (!options || strncmp(options, "sb=", 3) != 0)
 394                return 1;       /* Default location */
 395        options += 3;
 396        sb_block = simple_strtoul(options, &options, 0);
 397        if (*options && *options != ',') {
 398                printk("EXT2-fs: Invalid sb specification: %s\n",
 399                       (char *) *data);
 400                return 1;
 401        }
 402        if (*options == ',')
 403                options++;
 404        *data = (void *) options;
 405        return sb_block;
 406}
 407
 408enum {
 409        Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
 410        Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
 411        Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
 412        Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
 413        Opt_acl, Opt_noacl, Opt_xip, Opt_dax, Opt_ignore, Opt_err, Opt_quota,
 414        Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
 415};
 416
 417static const match_table_t tokens = {
 418        {Opt_bsd_df, "bsddf"},
 419        {Opt_minix_df, "minixdf"},
 420        {Opt_grpid, "grpid"},
 421        {Opt_grpid, "bsdgroups"},
 422        {Opt_nogrpid, "nogrpid"},
 423        {Opt_nogrpid, "sysvgroups"},
 424        {Opt_resgid, "resgid=%u"},
 425        {Opt_resuid, "resuid=%u"},
 426        {Opt_sb, "sb=%u"},
 427        {Opt_err_cont, "errors=continue"},
 428        {Opt_err_panic, "errors=panic"},
 429        {Opt_err_ro, "errors=remount-ro"},
 430        {Opt_nouid32, "nouid32"},
 431        {Opt_nocheck, "check=none"},
 432        {Opt_nocheck, "nocheck"},
 433        {Opt_debug, "debug"},
 434        {Opt_oldalloc, "oldalloc"},
 435        {Opt_orlov, "orlov"},
 436        {Opt_nobh, "nobh"},
 437        {Opt_user_xattr, "user_xattr"},
 438        {Opt_nouser_xattr, "nouser_xattr"},
 439        {Opt_acl, "acl"},
 440        {Opt_noacl, "noacl"},
 441        {Opt_xip, "xip"},
 442        {Opt_dax, "dax"},
 443        {Opt_grpquota, "grpquota"},
 444        {Opt_ignore, "noquota"},
 445        {Opt_quota, "quota"},
 446        {Opt_usrquota, "usrquota"},
 447        {Opt_reservation, "reservation"},
 448        {Opt_noreservation, "noreservation"},
 449        {Opt_err, NULL}
 450};
 451
 452static int parse_options(char *options, struct super_block *sb)
 453{
 454        char *p;
 455        struct ext2_sb_info *sbi = EXT2_SB(sb);
 456        substring_t args[MAX_OPT_ARGS];
 457        int option;
 458        kuid_t uid;
 459        kgid_t gid;
 460
 461        if (!options)
 462                return 1;
 463
 464        while ((p = strsep (&options, ",")) != NULL) {
 465                int token;
 466                if (!*p)
 467                        continue;
 468
 469                token = match_token(p, tokens, args);
 470                switch (token) {
 471                case Opt_bsd_df:
 472                        clear_opt (sbi->s_mount_opt, MINIX_DF);
 473                        break;
 474                case Opt_minix_df:
 475                        set_opt (sbi->s_mount_opt, MINIX_DF);
 476                        break;
 477                case Opt_grpid:
 478                        set_opt (sbi->s_mount_opt, GRPID);
 479                        break;
 480                case Opt_nogrpid:
 481                        clear_opt (sbi->s_mount_opt, GRPID);
 482                        break;
 483                case Opt_resuid:
 484                        if (match_int(&args[0], &option))
 485                                return 0;
 486                        uid = make_kuid(current_user_ns(), option);
 487                        if (!uid_valid(uid)) {
 488                                ext2_msg(sb, KERN_ERR, "Invalid uid value %d", option);
 489                                return 0;
 490
 491                        }
 492                        sbi->s_resuid = uid;
 493                        break;
 494                case Opt_resgid:
 495                        if (match_int(&args[0], &option))
 496                                return 0;
 497                        gid = make_kgid(current_user_ns(), option);
 498                        if (!gid_valid(gid)) {
 499                                ext2_msg(sb, KERN_ERR, "Invalid gid value %d", option);
 500                                return 0;
 501                        }
 502                        sbi->s_resgid = gid;
 503                        break;
 504                case Opt_sb:
 505                        /* handled by get_sb_block() instead of here */
 506                        /* *sb_block = match_int(&args[0]); */
 507                        break;
 508                case Opt_err_panic:
 509                        clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 510                        clear_opt (sbi->s_mount_opt, ERRORS_RO);
 511                        set_opt (sbi->s_mount_opt, ERRORS_PANIC);
 512                        break;
 513                case Opt_err_ro:
 514                        clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 515                        clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 516                        set_opt (sbi->s_mount_opt, ERRORS_RO);
 517                        break;
 518                case Opt_err_cont:
 519                        clear_opt (sbi->s_mount_opt, ERRORS_RO);
 520                        clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 521                        set_opt (sbi->s_mount_opt, ERRORS_CONT);
 522                        break;
 523                case Opt_nouid32:
 524                        set_opt (sbi->s_mount_opt, NO_UID32);
 525                        break;
 526                case Opt_nocheck:
 527                        clear_opt (sbi->s_mount_opt, CHECK);
 528                        break;
 529                case Opt_debug:
 530                        set_opt (sbi->s_mount_opt, DEBUG);
 531                        break;
 532                case Opt_oldalloc:
 533                        set_opt (sbi->s_mount_opt, OLDALLOC);
 534                        break;
 535                case Opt_orlov:
 536                        clear_opt (sbi->s_mount_opt, OLDALLOC);
 537                        break;
 538                case Opt_nobh:
 539                        set_opt (sbi->s_mount_opt, NOBH);
 540                        break;
 541#ifdef CONFIG_EXT2_FS_XATTR
 542                case Opt_user_xattr:
 543                        set_opt (sbi->s_mount_opt, XATTR_USER);
 544                        break;
 545                case Opt_nouser_xattr:
 546                        clear_opt (sbi->s_mount_opt, XATTR_USER);
 547                        break;
 548#else
 549                case Opt_user_xattr:
 550                case Opt_nouser_xattr:
 551                        ext2_msg(sb, KERN_INFO, "(no)user_xattr options"
 552                                "not supported");
 553                        break;
 554#endif
 555#ifdef CONFIG_EXT2_FS_POSIX_ACL
 556                case Opt_acl:
 557                        set_opt(sbi->s_mount_opt, POSIX_ACL);
 558                        break;
 559                case Opt_noacl:
 560                        clear_opt(sbi->s_mount_opt, POSIX_ACL);
 561                        break;
 562#else
 563                case Opt_acl:
 564                case Opt_noacl:
 565                        ext2_msg(sb, KERN_INFO,
 566                                "(no)acl options not supported");
 567                        break;
 568#endif
 569                case Opt_xip:
 570                        ext2_msg(sb, KERN_INFO, "use dax instead of xip");
 571                        set_opt(sbi->s_mount_opt, XIP);
 572                        /* Fall through */
 573                case Opt_dax:
 574#ifdef CONFIG_FS_DAX
 575                        ext2_msg(sb, KERN_WARNING,
 576                "DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
 577                        set_opt(sbi->s_mount_opt, DAX);
 578#else
 579                        ext2_msg(sb, KERN_INFO, "dax option not supported");
 580#endif
 581                        break;
 582
 583#if defined(CONFIG_QUOTA)
 584                case Opt_quota:
 585                case Opt_usrquota:
 586                        set_opt(sbi->s_mount_opt, USRQUOTA);
 587                        break;
 588
 589                case Opt_grpquota:
 590                        set_opt(sbi->s_mount_opt, GRPQUOTA);
 591                        break;
 592#else
 593                case Opt_quota:
 594                case Opt_usrquota:
 595                case Opt_grpquota:
 596                        ext2_msg(sb, KERN_INFO,
 597                                "quota operations not supported");
 598                        break;
 599#endif
 600
 601                case Opt_reservation:
 602                        set_opt(sbi->s_mount_opt, RESERVATION);
 603                        ext2_msg(sb, KERN_INFO, "reservations ON");
 604                        break;
 605                case Opt_noreservation:
 606                        clear_opt(sbi->s_mount_opt, RESERVATION);
 607                        ext2_msg(sb, KERN_INFO, "reservations OFF");
 608                        break;
 609                case Opt_ignore:
 610                        break;
 611                default:
 612                        return 0;
 613                }
 614        }
 615        return 1;
 616}
 617
 618static int ext2_setup_super (struct super_block * sb,
 619                              struct ext2_super_block * es,
 620                              int read_only)
 621{
 622        int res = 0;
 623        struct ext2_sb_info *sbi = EXT2_SB(sb);
 624
 625        if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 626                ext2_msg(sb, KERN_ERR,
 627                        "error: revision level too high, "
 628                        "forcing read-only mode");
 629                res = MS_RDONLY;
 630        }
 631        if (read_only)
 632                return res;
 633        if (!(sbi->s_mount_state & EXT2_VALID_FS))
 634                ext2_msg(sb, KERN_WARNING,
 635                        "warning: mounting unchecked fs, "
 636                        "running e2fsck is recommended");
 637        else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 638                ext2_msg(sb, KERN_WARNING,
 639                        "warning: mounting fs with errors, "
 640                        "running e2fsck is recommended");
 641        else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 642                 le16_to_cpu(es->s_mnt_count) >=
 643                 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 644                ext2_msg(sb, KERN_WARNING,
 645                        "warning: maximal mount count reached, "
 646                        "running e2fsck is recommended");
 647        else if (le32_to_cpu(es->s_checkinterval) &&
 648                (le32_to_cpu(es->s_lastcheck) +
 649                        le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 650                ext2_msg(sb, KERN_WARNING,
 651                        "warning: checktime reached, "
 652                        "running e2fsck is recommended");
 653        if (!le16_to_cpu(es->s_max_mnt_count))
 654                es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 655        le16_add_cpu(&es->s_mnt_count, 1);
 656        if (test_opt (sb, DEBUG))
 657                ext2_msg(sb, KERN_INFO, "%s, %s, bs=%lu, fs=%lu, gc=%lu, "
 658                        "bpg=%lu, ipg=%lu, mo=%04lx]",
 659                        EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 660                        sbi->s_frag_size,
 661                        sbi->s_groups_count,
 662                        EXT2_BLOCKS_PER_GROUP(sb),
 663                        EXT2_INODES_PER_GROUP(sb),
 664                        sbi->s_mount_opt);
 665        return res;
 666}
 667
 668static int ext2_check_descriptors(struct super_block *sb)
 669{
 670        int i;
 671        struct ext2_sb_info *sbi = EXT2_SB(sb);
 672
 673        ext2_debug ("Checking group descriptors");
 674
 675        for (i = 0; i < sbi->s_groups_count; i++) {
 676                struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
 677                ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
 678                ext2_fsblk_t last_block;
 679
 680                if (i == sbi->s_groups_count - 1)
 681                        last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
 682                else
 683                        last_block = first_block +
 684                                (EXT2_BLOCKS_PER_GROUP(sb) - 1);
 685
 686                if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
 687                    le32_to_cpu(gdp->bg_block_bitmap) > last_block)
 688                {
 689                        ext2_error (sb, "ext2_check_descriptors",
 690                                    "Block bitmap for group %d"
 691                                    " not in group (block %lu)!",
 692                                    i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 693                        return 0;
 694                }
 695                if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
 696                    le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
 697                {
 698                        ext2_error (sb, "ext2_check_descriptors",
 699                                    "Inode bitmap for group %d"
 700                                    " not in group (block %lu)!",
 701                                    i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 702                        return 0;
 703                }
 704                if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
 705                    le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
 706                    last_block)
 707                {
 708                        ext2_error (sb, "ext2_check_descriptors",
 709                                    "Inode table for group %d"
 710                                    " not in group (block %lu)!",
 711                                    i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 712                        return 0;
 713                }
 714        }
 715        return 1;
 716}
 717
 718/*
 719 * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 720 * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 721 * We need to be 1 filesystem block less than the 2^32 sector limit.
 722 */
 723static loff_t ext2_max_size(int bits)
 724{
 725        loff_t res = EXT2_NDIR_BLOCKS;
 726        int meta_blocks;
 727        loff_t upper_limit;
 728
 729        /* This is calculated to be the largest file size for a
 730         * dense, file such that the total number of
 731         * sectors in the file, including data and all indirect blocks,
 732         * does not exceed 2^32 -1
 733         * __u32 i_blocks representing the total number of
 734         * 512 bytes blocks of the file
 735         */
 736        upper_limit = (1LL << 32) - 1;
 737
 738        /* total blocks in file system block size */
 739        upper_limit >>= (bits - 9);
 740
 741
 742        /* indirect blocks */
 743        meta_blocks = 1;
 744        /* double indirect blocks */
 745        meta_blocks += 1 + (1LL << (bits-2));
 746        /* tripple indirect blocks */
 747        meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
 748
 749        upper_limit -= meta_blocks;
 750        upper_limit <<= bits;
 751
 752        res += 1LL << (bits-2);
 753        res += 1LL << (2*(bits-2));
 754        res += 1LL << (3*(bits-2));
 755        res <<= bits;
 756        if (res > upper_limit)
 757                res = upper_limit;
 758
 759        if (res > MAX_LFS_FILESIZE)
 760                res = MAX_LFS_FILESIZE;
 761
 762        return res;
 763}
 764
 765static unsigned long descriptor_loc(struct super_block *sb,
 766                                    unsigned long logic_sb_block,
 767                                    int nr)
 768{
 769        struct ext2_sb_info *sbi = EXT2_SB(sb);
 770        unsigned long bg, first_meta_bg;
 771        int has_super = 0;
 772        
 773        first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 774
 775        if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 776            nr < first_meta_bg)
 777                return (logic_sb_block + nr + 1);
 778        bg = sbi->s_desc_per_block * nr;
 779        if (ext2_bg_has_super(sb, bg))
 780                has_super = 1;
 781
 782        return ext2_group_first_block_no(sb, bg) + has_super;
 783}
 784
 785static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 786{
 787        struct buffer_head * bh;
 788        struct ext2_sb_info * sbi;
 789        struct ext2_super_block * es;
 790        struct inode *root;
 791        unsigned long block;
 792        unsigned long sb_block = get_sb_block(&data);
 793        unsigned long logic_sb_block;
 794        unsigned long offset = 0;
 795        unsigned long def_mount_opts;
 796        long ret = -EINVAL;
 797        int blocksize = BLOCK_SIZE;
 798        int db_count;
 799        int i, j;
 800        __le32 features;
 801        int err;
 802
 803        err = -ENOMEM;
 804        sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 805        if (!sbi)
 806                goto failed;
 807
 808        sbi->s_blockgroup_lock =
 809                kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
 810        if (!sbi->s_blockgroup_lock) {
 811                kfree(sbi);
 812                goto failed;
 813        }
 814        sb->s_fs_info = sbi;
 815        sbi->s_sb_block = sb_block;
 816
 817        spin_lock_init(&sbi->s_lock);
 818
 819        /*
 820         * See what the current blocksize for the device is, and
 821         * use that as the blocksize.  Otherwise (or if the blocksize
 822         * is smaller than the default) use the default.
 823         * This is important for devices that have a hardware
 824         * sectorsize that is larger than the default.
 825         */
 826        blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 827        if (!blocksize) {
 828                ext2_msg(sb, KERN_ERR, "error: unable to set blocksize");
 829                goto failed_sbi;
 830        }
 831
 832        /*
 833         * If the superblock doesn't start on a hardware sector boundary,
 834         * calculate the offset.  
 835         */
 836        if (blocksize != BLOCK_SIZE) {
 837                logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 838                offset = (sb_block*BLOCK_SIZE) % blocksize;
 839        } else {
 840                logic_sb_block = sb_block;
 841        }
 842
 843        if (!(bh = sb_bread(sb, logic_sb_block))) {
 844                ext2_msg(sb, KERN_ERR, "error: unable to read superblock");
 845                goto failed_sbi;
 846        }
 847        /*
 848         * Note: s_es must be initialized as soon as possible because
 849         *       some ext2 macro-instructions depend on its value
 850         */
 851        es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 852        sbi->s_es = es;
 853        sb->s_magic = le16_to_cpu(es->s_magic);
 854
 855        if (sb->s_magic != EXT2_SUPER_MAGIC)
 856                goto cantfind_ext2;
 857
 858        /* Set defaults before we parse the mount options */
 859        def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 860        if (def_mount_opts & EXT2_DEFM_DEBUG)
 861                set_opt(sbi->s_mount_opt, DEBUG);
 862        if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 863                set_opt(sbi->s_mount_opt, GRPID);
 864        if (def_mount_opts & EXT2_DEFM_UID16)
 865                set_opt(sbi->s_mount_opt, NO_UID32);
 866#ifdef CONFIG_EXT2_FS_XATTR
 867        if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 868                set_opt(sbi->s_mount_opt, XATTR_USER);
 869#endif
 870#ifdef CONFIG_EXT2_FS_POSIX_ACL
 871        if (def_mount_opts & EXT2_DEFM_ACL)
 872                set_opt(sbi->s_mount_opt, POSIX_ACL);
 873#endif
 874        
 875        if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 876                set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 877        else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
 878                set_opt(sbi->s_mount_opt, ERRORS_CONT);
 879        else
 880                set_opt(sbi->s_mount_opt, ERRORS_RO);
 881
 882        sbi->s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
 883        sbi->s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
 884        
 885        set_opt(sbi->s_mount_opt, RESERVATION);
 886
 887        if (!parse_options((char *) data, sb))
 888                goto failed_mount;
 889
 890        sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 891                ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 892                 MS_POSIXACL : 0);
 893        sb->s_iflags |= SB_I_CGROUPWB;
 894
 895        if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 896            (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 897             EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 898             EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 899                ext2_msg(sb, KERN_WARNING,
 900                        "warning: feature flags set on rev 0 fs, "
 901                        "running e2fsck is recommended");
 902        /*
 903         * Check feature flags regardless of the revision level, since we
 904         * previously didn't change the revision level when setting the flags,
 905         * so there is a chance incompat flags are set on a rev 0 filesystem.
 906         */
 907        features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 908        if (features) {
 909                ext2_msg(sb, KERN_ERR,  "error: couldn't mount because of "
 910                       "unsupported optional features (%x)",
 911                        le32_to_cpu(features));
 912                goto failed_mount;
 913        }
 914        if (!(sb->s_flags & MS_RDONLY) &&
 915            (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 916                ext2_msg(sb, KERN_ERR, "error: couldn't mount RDWR because of "
 917                       "unsupported optional features (%x)",
 918                       le32_to_cpu(features));
 919                goto failed_mount;
 920        }
 921
 922        blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 923
 924        if (sbi->s_mount_opt & EXT2_MOUNT_DAX) {
 925                err = bdev_dax_supported(sb, blocksize);
 926                if (err)
 927                        goto failed_mount;
 928        }
 929
 930        /* If the blocksize doesn't match, re-read the thing.. */
 931        if (sb->s_blocksize != blocksize) {
 932                brelse(bh);
 933
 934                if (!sb_set_blocksize(sb, blocksize)) {
 935                        ext2_msg(sb, KERN_ERR,
 936                                "error: bad blocksize %d", blocksize);
 937                        goto failed_sbi;
 938                }
 939
 940                logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 941                offset = (sb_block*BLOCK_SIZE) % blocksize;
 942                bh = sb_bread(sb, logic_sb_block);
 943                if(!bh) {
 944                        ext2_msg(sb, KERN_ERR, "error: couldn't read"
 945                                "superblock on 2nd try");
 946                        goto failed_sbi;
 947                }
 948                es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 949                sbi->s_es = es;
 950                if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 951                        ext2_msg(sb, KERN_ERR, "error: magic mismatch");
 952                        goto failed_mount;
 953                }
 954        }
 955
 956        sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 957        sb->s_max_links = EXT2_LINK_MAX;
 958
 959        if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 960                sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 961                sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 962        } else {
 963                sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 964                sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 965                if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 966                    !is_power_of_2(sbi->s_inode_size) ||
 967                    (sbi->s_inode_size > blocksize)) {
 968                        ext2_msg(sb, KERN_ERR,
 969                                "error: unsupported inode size: %d",
 970                                sbi->s_inode_size);
 971                        goto failed_mount;
 972                }
 973        }
 974
 975        sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 976                                   le32_to_cpu(es->s_log_frag_size);
 977        if (sbi->s_frag_size == 0)
 978                goto cantfind_ext2;
 979        sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
 980
 981        sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 982        sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 983        sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 984
 985        if (EXT2_INODE_SIZE(sb) == 0)
 986                goto cantfind_ext2;
 987        sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
 988        if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
 989                goto cantfind_ext2;
 990        sbi->s_itb_per_group = sbi->s_inodes_per_group /
 991                                        sbi->s_inodes_per_block;
 992        sbi->s_desc_per_block = sb->s_blocksize /
 993                                        sizeof (struct ext2_group_desc);
 994        sbi->s_sbh = bh;
 995        sbi->s_mount_state = le16_to_cpu(es->s_state);
 996        sbi->s_addr_per_block_bits =
 997                ilog2 (EXT2_ADDR_PER_BLOCK(sb));
 998        sbi->s_desc_per_block_bits =
 999                ilog2 (EXT2_DESC_PER_BLOCK(sb));
1000
1001        if (sb->s_magic != EXT2_SUPER_MAGIC)
1002                goto cantfind_ext2;
1003
1004        if (sb->s_blocksize != bh->b_size) {
1005                if (!silent)
1006                        ext2_msg(sb, KERN_ERR, "error: unsupported blocksize");
1007                goto failed_mount;
1008        }
1009
1010        if (sb->s_blocksize != sbi->s_frag_size) {
1011                ext2_msg(sb, KERN_ERR,
1012                        "error: fragsize %lu != blocksize %lu"
1013                        "(not supported yet)",
1014                        sbi->s_frag_size, sb->s_blocksize);
1015                goto failed_mount;
1016        }
1017
1018        if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
1019                ext2_msg(sb, KERN_ERR,
1020                        "error: #blocks per group too big: %lu",
1021                        sbi->s_blocks_per_group);
1022                goto failed_mount;
1023        }
1024        if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
1025                ext2_msg(sb, KERN_ERR,
1026                        "error: #fragments per group too big: %lu",
1027                        sbi->s_frags_per_group);
1028                goto failed_mount;
1029        }
1030        if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
1031                ext2_msg(sb, KERN_ERR,
1032                        "error: #inodes per group too big: %lu",
1033                        sbi->s_inodes_per_group);
1034                goto failed_mount;
1035        }
1036
1037        if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
1038                goto cantfind_ext2;
1039        sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
1040                                le32_to_cpu(es->s_first_data_block) - 1)
1041                                        / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
1042        db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
1043                   EXT2_DESC_PER_BLOCK(sb);
1044        sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
1045        if (sbi->s_group_desc == NULL) {
1046                ext2_msg(sb, KERN_ERR, "error: not enough memory");
1047                goto failed_mount;
1048        }
1049        bgl_lock_init(sbi->s_blockgroup_lock);
1050        sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
1051        if (!sbi->s_debts) {
1052                ext2_msg(sb, KERN_ERR, "error: not enough memory");
1053                goto failed_mount_group_desc;
1054        }
1055        for (i = 0; i < db_count; i++) {
1056                block = descriptor_loc(sb, logic_sb_block, i);
1057                sbi->s_group_desc[i] = sb_bread(sb, block);
1058                if (!sbi->s_group_desc[i]) {
1059                        for (j = 0; j < i; j++)
1060                                brelse (sbi->s_group_desc[j]);
1061                        ext2_msg(sb, KERN_ERR,
1062                                "error: unable to read group descriptors");
1063                        goto failed_mount_group_desc;
1064                }
1065        }
1066        if (!ext2_check_descriptors (sb)) {
1067                ext2_msg(sb, KERN_ERR, "group descriptors corrupted");
1068                goto failed_mount2;
1069        }
1070        sbi->s_gdb_count = db_count;
1071        get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1072        spin_lock_init(&sbi->s_next_gen_lock);
1073
1074        /* per fileystem reservation list head & lock */
1075        spin_lock_init(&sbi->s_rsv_window_lock);
1076        sbi->s_rsv_window_root = RB_ROOT;
1077        /*
1078         * Add a single, static dummy reservation to the start of the
1079         * reservation window list --- it gives us a placeholder for
1080         * append-at-start-of-list which makes the allocation logic
1081         * _much_ simpler.
1082         */
1083        sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1084        sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1085        sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1086        sbi->s_rsv_window_head.rsv_goal_size = 0;
1087        ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1088
1089        err = percpu_counter_init(&sbi->s_freeblocks_counter,
1090                                ext2_count_free_blocks(sb), GFP_KERNEL);
1091        if (!err) {
1092                err = percpu_counter_init(&sbi->s_freeinodes_counter,
1093                                ext2_count_free_inodes(sb), GFP_KERNEL);
1094        }
1095        if (!err) {
1096                err = percpu_counter_init(&sbi->s_dirs_counter,
1097                                ext2_count_dirs(sb), GFP_KERNEL);
1098        }
1099        if (err) {
1100                ext2_msg(sb, KERN_ERR, "error: insufficient memory");
1101                goto failed_mount3;
1102        }
1103
1104#ifdef CONFIG_EXT2_FS_XATTR
1105        sbi->s_mb_cache = ext2_xattr_create_cache();
1106        if (!sbi->s_mb_cache) {
1107                ext2_msg(sb, KERN_ERR, "Failed to create an mb_cache");
1108                goto failed_mount3;
1109        }
1110#endif
1111        /*
1112         * set up enough so that it can read an inode
1113         */
1114        sb->s_op = &ext2_sops;
1115        sb->s_export_op = &ext2_export_ops;
1116        sb->s_xattr = ext2_xattr_handlers;
1117
1118#ifdef CONFIG_QUOTA
1119        sb->dq_op = &dquot_operations;
1120        sb->s_qcop = &dquot_quotactl_ops;
1121        sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP;
1122#endif
1123
1124        root = ext2_iget(sb, EXT2_ROOT_INO);
1125        if (IS_ERR(root)) {
1126                ret = PTR_ERR(root);
1127                goto failed_mount3;
1128        }
1129        if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1130                iput(root);
1131                ext2_msg(sb, KERN_ERR, "error: corrupt root inode, run e2fsck");
1132                goto failed_mount3;
1133        }
1134
1135        sb->s_root = d_make_root(root);
1136        if (!sb->s_root) {
1137                ext2_msg(sb, KERN_ERR, "error: get root inode failed");
1138                ret = -ENOMEM;
1139                goto failed_mount3;
1140        }
1141        if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1142                ext2_msg(sb, KERN_WARNING,
1143                        "warning: mounting ext3 filesystem as ext2");
1144        if (ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY))
1145                sb->s_flags |= MS_RDONLY;
1146        ext2_write_super(sb);
1147        return 0;
1148
1149cantfind_ext2:
1150        if (!silent)
1151                ext2_msg(sb, KERN_ERR,
1152                        "error: can't find an ext2 filesystem on dev %s.",
1153                        sb->s_id);
1154        goto failed_mount;
1155failed_mount3:
1156        if (sbi->s_mb_cache)
1157                ext2_xattr_destroy_cache(sbi->s_mb_cache);
1158        percpu_counter_destroy(&sbi->s_freeblocks_counter);
1159        percpu_counter_destroy(&sbi->s_freeinodes_counter);
1160        percpu_counter_destroy(&sbi->s_dirs_counter);
1161failed_mount2:
1162        for (i = 0; i < db_count; i++)
1163                brelse(sbi->s_group_desc[i]);
1164failed_mount_group_desc:
1165        kfree(sbi->s_group_desc);
1166        kfree(sbi->s_debts);
1167failed_mount:
1168        brelse(bh);
1169failed_sbi:
1170        sb->s_fs_info = NULL;
1171        kfree(sbi->s_blockgroup_lock);
1172        kfree(sbi);
1173failed:
1174        return ret;
1175}
1176
1177static void ext2_clear_super_error(struct super_block *sb)
1178{
1179        struct buffer_head *sbh = EXT2_SB(sb)->s_sbh;
1180
1181        if (buffer_write_io_error(sbh)) {
1182                /*
1183                 * Oh, dear.  A previous attempt to write the
1184                 * superblock failed.  This could happen because the
1185                 * USB device was yanked out.  Or it could happen to
1186                 * be a transient write error and maybe the block will
1187                 * be remapped.  Nothing we can do but to retry the
1188                 * write and hope for the best.
1189                 */
1190                ext2_msg(sb, KERN_ERR,
1191                       "previous I/O error to superblock detected\n");
1192                clear_buffer_write_io_error(sbh);
1193                set_buffer_uptodate(sbh);
1194        }
1195}
1196
1197static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
1198                            int wait)
1199{
1200        ext2_clear_super_error(sb);
1201        spin_lock(&EXT2_SB(sb)->s_lock);
1202        es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1203        es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1204        es->s_wtime = cpu_to_le32(get_seconds());
1205        /* unlock before we do IO */
1206        spin_unlock(&EXT2_SB(sb)->s_lock);
1207        mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1208        if (wait)
1209                sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1210}
1211
1212/*
1213 * In the second extended file system, it is not necessary to
1214 * write the super block since we use a mapping of the
1215 * disk super block in a buffer.
1216 *
1217 * However, this function is still used to set the fs valid
1218 * flags to 0.  We need to set this flag to 0 since the fs
1219 * may have been checked while mounted and e2fsck may have
1220 * set s_state to EXT2_VALID_FS after some corrections.
1221 */
1222static int ext2_sync_fs(struct super_block *sb, int wait)
1223{
1224        struct ext2_sb_info *sbi = EXT2_SB(sb);
1225        struct ext2_super_block *es = EXT2_SB(sb)->s_es;
1226
1227        /*
1228         * Write quota structures to quota file, sync_blockdev() will write
1229         * them to disk later
1230         */
1231        dquot_writeback_dquots(sb, -1);
1232
1233        spin_lock(&sbi->s_lock);
1234        if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1235                ext2_debug("setting valid to 0\n");
1236                es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1237        }
1238        spin_unlock(&sbi->s_lock);
1239        ext2_sync_super(sb, es, wait);
1240        return 0;
1241}
1242
1243static int ext2_freeze(struct super_block *sb)
1244{
1245        struct ext2_sb_info *sbi = EXT2_SB(sb);
1246
1247        /*
1248         * Open but unlinked files present? Keep EXT2_VALID_FS flag cleared
1249         * because we have unattached inodes and thus filesystem is not fully
1250         * consistent.
1251         */
1252        if (atomic_long_read(&sb->s_remove_count)) {
1253                ext2_sync_fs(sb, 1);
1254                return 0;
1255        }
1256        /* Set EXT2_FS_VALID flag */
1257        spin_lock(&sbi->s_lock);
1258        sbi->s_es->s_state = cpu_to_le16(sbi->s_mount_state);
1259        spin_unlock(&sbi->s_lock);
1260        ext2_sync_super(sb, sbi->s_es, 1);
1261
1262        return 0;
1263}
1264
1265static int ext2_unfreeze(struct super_block *sb)
1266{
1267        /* Just write sb to clear EXT2_VALID_FS flag */
1268        ext2_write_super(sb);
1269
1270        return 0;
1271}
1272
1273void ext2_write_super(struct super_block *sb)
1274{
1275        if (!(sb->s_flags & MS_RDONLY))
1276                ext2_sync_fs(sb, 1);
1277}
1278
1279static int ext2_remount (struct super_block * sb, int * flags, char * data)
1280{
1281        struct ext2_sb_info * sbi = EXT2_SB(sb);
1282        struct ext2_super_block * es;
1283        struct ext2_mount_options old_opts;
1284        unsigned long old_sb_flags;
1285        int err;
1286
1287        sync_filesystem(sb);
1288        spin_lock(&sbi->s_lock);
1289
1290        /* Store the old options */
1291        old_sb_flags = sb->s_flags;
1292        old_opts.s_mount_opt = sbi->s_mount_opt;
1293        old_opts.s_resuid = sbi->s_resuid;
1294        old_opts.s_resgid = sbi->s_resgid;
1295
1296        /*
1297         * Allow the "check" option to be passed as a remount option.
1298         */
1299        if (!parse_options(data, sb)) {
1300                err = -EINVAL;
1301                goto restore_opts;
1302        }
1303
1304        sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1305                ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1306
1307        es = sbi->s_es;
1308        if ((sbi->s_mount_opt ^ old_opts.s_mount_opt) & EXT2_MOUNT_DAX) {
1309                ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
1310                         "dax flag with busy inodes while remounting");
1311                sbi->s_mount_opt ^= EXT2_MOUNT_DAX;
1312        }
1313        if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
1314                spin_unlock(&sbi->s_lock);
1315                return 0;
1316        }
1317        if (*flags & MS_RDONLY) {
1318                if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1319                    !(sbi->s_mount_state & EXT2_VALID_FS)) {
1320                        spin_unlock(&sbi->s_lock);
1321                        return 0;
1322                }
1323
1324                /*
1325                 * OK, we are remounting a valid rw partition rdonly, so set
1326                 * the rdonly flag and then mark the partition as valid again.
1327                 */
1328                es->s_state = cpu_to_le16(sbi->s_mount_state);
1329                es->s_mtime = cpu_to_le32(get_seconds());
1330                spin_unlock(&sbi->s_lock);
1331
1332                err = dquot_suspend(sb, -1);
1333                if (err < 0) {
1334                        spin_lock(&sbi->s_lock);
1335                        goto restore_opts;
1336                }
1337
1338                ext2_sync_super(sb, es, 1);
1339        } else {
1340                __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1341                                               ~EXT2_FEATURE_RO_COMPAT_SUPP);
1342                if (ret) {
1343                        ext2_msg(sb, KERN_WARNING,
1344                                "warning: couldn't remount RDWR because of "
1345                                "unsupported optional features (%x).",
1346                                le32_to_cpu(ret));
1347                        err = -EROFS;
1348                        goto restore_opts;
1349                }
1350                /*
1351                 * Mounting a RDONLY partition read-write, so reread and
1352                 * store the current valid flag.  (It may have been changed
1353                 * by e2fsck since we originally mounted the partition.)
1354                 */
1355                sbi->s_mount_state = le16_to_cpu(es->s_state);
1356                if (!ext2_setup_super (sb, es, 0))
1357                        sb->s_flags &= ~MS_RDONLY;
1358                spin_unlock(&sbi->s_lock);
1359
1360                ext2_write_super(sb);
1361
1362                dquot_resume(sb, -1);
1363        }
1364
1365        return 0;
1366restore_opts:
1367        sbi->s_mount_opt = old_opts.s_mount_opt;
1368        sbi->s_resuid = old_opts.s_resuid;
1369        sbi->s_resgid = old_opts.s_resgid;
1370        sb->s_flags = old_sb_flags;
1371        spin_unlock(&sbi->s_lock);
1372        return err;
1373}
1374
1375static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1376{
1377        struct super_block *sb = dentry->d_sb;
1378        struct ext2_sb_info *sbi = EXT2_SB(sb);
1379        struct ext2_super_block *es = sbi->s_es;
1380        u64 fsid;
1381
1382        spin_lock(&sbi->s_lock);
1383
1384        if (test_opt (sb, MINIX_DF))
1385                sbi->s_overhead_last = 0;
1386        else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1387                unsigned long i, overhead = 0;
1388                smp_rmb();
1389
1390                /*
1391                 * Compute the overhead (FS structures). This is constant
1392                 * for a given filesystem unless the number of block groups
1393                 * changes so we cache the previous value until it does.
1394                 */
1395
1396                /*
1397                 * All of the blocks before first_data_block are
1398                 * overhead
1399                 */
1400                overhead = le32_to_cpu(es->s_first_data_block);
1401
1402                /*
1403                 * Add the overhead attributed to the superblock and
1404                 * block group descriptors.  If the sparse superblocks
1405                 * feature is turned on, then not all groups have this.
1406                 */
1407                for (i = 0; i < sbi->s_groups_count; i++)
1408                        overhead += ext2_bg_has_super(sb, i) +
1409                                ext2_bg_num_gdb(sb, i);
1410
1411                /*
1412                 * Every block group has an inode bitmap, a block
1413                 * bitmap, and an inode table.
1414                 */
1415                overhead += (sbi->s_groups_count *
1416                             (2 + sbi->s_itb_per_group));
1417                sbi->s_overhead_last = overhead;
1418                smp_wmb();
1419                sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1420        }
1421
1422        buf->f_type = EXT2_SUPER_MAGIC;
1423        buf->f_bsize = sb->s_blocksize;
1424        buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1425        buf->f_bfree = ext2_count_free_blocks(sb);
1426        es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1427        buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1428        if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1429                buf->f_bavail = 0;
1430        buf->f_files = le32_to_cpu(es->s_inodes_count);
1431        buf->f_ffree = ext2_count_free_inodes(sb);
1432        es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1433        buf->f_namelen = EXT2_NAME_LEN;
1434        fsid = le64_to_cpup((void *)es->s_uuid) ^
1435               le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1436        buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1437        buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1438        spin_unlock(&sbi->s_lock);
1439        return 0;
1440}
1441
1442static struct dentry *ext2_mount(struct file_system_type *fs_type,
1443        int flags, const char *dev_name, void *data)
1444{
1445        return mount_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1446}
1447
1448#ifdef CONFIG_QUOTA
1449
1450/* Read data from quotafile - avoid pagecache and such because we cannot afford
1451 * acquiring the locks... As quota files are never truncated and quota code
1452 * itself serializes the operations (and no one else should touch the files)
1453 * we don't have to be afraid of races */
1454static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1455                               size_t len, loff_t off)
1456{
1457        struct inode *inode = sb_dqopt(sb)->files[type];
1458        sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1459        int err = 0;
1460        int offset = off & (sb->s_blocksize - 1);
1461        int tocopy;
1462        size_t toread;
1463        struct buffer_head tmp_bh;
1464        struct buffer_head *bh;
1465        loff_t i_size = i_size_read(inode);
1466
1467        if (off > i_size)
1468                return 0;
1469        if (off+len > i_size)
1470                len = i_size-off;
1471        toread = len;
1472        while (toread > 0) {
1473                tocopy = sb->s_blocksize - offset < toread ?
1474                                sb->s_blocksize - offset : toread;
1475
1476                tmp_bh.b_state = 0;
1477                tmp_bh.b_size = sb->s_blocksize;
1478                err = ext2_get_block(inode, blk, &tmp_bh, 0);
1479                if (err < 0)
1480                        return err;
1481                if (!buffer_mapped(&tmp_bh))    /* A hole? */
1482                        memset(data, 0, tocopy);
1483                else {
1484                        bh = sb_bread(sb, tmp_bh.b_blocknr);
1485                        if (!bh)
1486                                return -EIO;
1487                        memcpy(data, bh->b_data+offset, tocopy);
1488                        brelse(bh);
1489                }
1490                offset = 0;
1491                toread -= tocopy;
1492                data += tocopy;
1493                blk++;
1494        }
1495        return len;
1496}
1497
1498/* Write to quotafile */
1499static ssize_t ext2_quota_write(struct super_block *sb, int type,
1500                                const char *data, size_t len, loff_t off)
1501{
1502        struct inode *inode = sb_dqopt(sb)->files[type];
1503        sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1504        int err = 0;
1505        int offset = off & (sb->s_blocksize - 1);
1506        int tocopy;
1507        size_t towrite = len;
1508        struct buffer_head tmp_bh;
1509        struct buffer_head *bh;
1510
1511        while (towrite > 0) {
1512                tocopy = sb->s_blocksize - offset < towrite ?
1513                                sb->s_blocksize - offset : towrite;
1514
1515                tmp_bh.b_state = 0;
1516                tmp_bh.b_size = sb->s_blocksize;
1517                err = ext2_get_block(inode, blk, &tmp_bh, 1);
1518                if (err < 0)
1519                        goto out;
1520                if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1521                        bh = sb_bread(sb, tmp_bh.b_blocknr);
1522                else
1523                        bh = sb_getblk(sb, tmp_bh.b_blocknr);
1524                if (unlikely(!bh)) {
1525                        err = -EIO;
1526                        goto out;
1527                }
1528                lock_buffer(bh);
1529                memcpy(bh->b_data+offset, data, tocopy);
1530                flush_dcache_page(bh->b_page);
1531                set_buffer_uptodate(bh);
1532                mark_buffer_dirty(bh);
1533                unlock_buffer(bh);
1534                brelse(bh);
1535                offset = 0;
1536                towrite -= tocopy;
1537                data += tocopy;
1538                blk++;
1539        }
1540out:
1541        if (len == towrite)
1542                return err;
1543        if (inode->i_size < off+len-towrite)
1544                i_size_write(inode, off+len-towrite);
1545        inode->i_version++;
1546        inode->i_mtime = inode->i_ctime = current_time(inode);
1547        mark_inode_dirty(inode);
1548        return len - towrite;
1549}
1550
1551#endif
1552
1553static struct file_system_type ext2_fs_type = {
1554        .owner          = THIS_MODULE,
1555        .name           = "ext2",
1556        .mount          = ext2_mount,
1557        .kill_sb        = kill_block_super,
1558        .fs_flags       = FS_REQUIRES_DEV,
1559};
1560MODULE_ALIAS_FS("ext2");
1561
1562static int __init init_ext2_fs(void)
1563{
1564        int err;
1565
1566        err = init_inodecache();
1567        if (err)
1568                return err;
1569        err = register_filesystem(&ext2_fs_type);
1570        if (err)
1571                goto out;
1572        return 0;
1573out:
1574        destroy_inodecache();
1575        return err;
1576}
1577
1578static void __exit exit_ext2_fs(void)
1579{
1580        unregister_filesystem(&ext2_fs_type);
1581        destroy_inodecache();
1582}
1583
1584MODULE_AUTHOR("Remy Card and others");
1585MODULE_DESCRIPTION("Second Extended Filesystem");
1586MODULE_LICENSE("GPL");
1587module_init(init_ext2_fs)
1588module_exit(exit_ext2_fs)
1589