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/smp_lock.h>
  30#include <linux/vfs.h>
  31#include <linux/seq_file.h>
  32#include <linux/mount.h>
  33#include <linux/log2.h>
  34#include <linux/quotaops.h>
  35#include <asm/uaccess.h>
  36#include "ext2.h"
  37#include "xattr.h"
  38#include "acl.h"
  39#include "xip.h"
  40
  41static void ext2_sync_super(struct super_block *sb,
  42                            struct ext2_super_block *es);
  43static int ext2_remount (struct super_block * sb, int * flags, char * data);
  44static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
  45static int ext2_sync_fs(struct super_block *sb, int wait);
  46
  47void ext2_error (struct super_block * sb, const char * function,
  48                 const char * fmt, ...)
  49{
  50        va_list args;
  51        struct ext2_sb_info *sbi = EXT2_SB(sb);
  52        struct ext2_super_block *es = sbi->s_es;
  53
  54        if (!(sb->s_flags & MS_RDONLY)) {
  55                sbi->s_mount_state |= EXT2_ERROR_FS;
  56                es->s_state |= cpu_to_le16(EXT2_ERROR_FS);
  57                ext2_sync_super(sb, es);
  58        }
  59
  60        va_start(args, fmt);
  61        printk(KERN_CRIT "EXT2-fs (%s): error: %s: ", sb->s_id, function);
  62        vprintk(fmt, args);
  63        printk("\n");
  64        va_end(args);
  65
  66        if (test_opt(sb, ERRORS_PANIC))
  67                panic("EXT2-fs: panic from previous error\n");
  68        if (test_opt(sb, ERRORS_RO)) {
  69                ext2_msg(sb, KERN_CRIT,
  70                             "error: remounting filesystem read-only");
  71                sb->s_flags |= MS_RDONLY;
  72        }
  73}
  74
  75void ext2_msg(struct super_block *sb, const char *prefix,
  76                const char *fmt, ...)
  77{
  78        va_list args;
  79
  80        va_start(args, fmt);
  81        printk("%sEXT2-fs (%s): ", prefix, sb->s_id);
  82        vprintk(fmt, args);
  83        printk("\n");
  84        va_end(args);
  85}
  86
  87void ext2_update_dynamic_rev(struct super_block *sb)
  88{
  89        struct ext2_super_block *es = EXT2_SB(sb)->s_es;
  90
  91        if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
  92                return;
  93
  94        ext2_msg(sb, KERN_WARNING,
  95                     "warning: updating to rev %d because of "
  96                     "new feature flag, running e2fsck is recommended",
  97                     EXT2_DYNAMIC_REV);
  98
  99        es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
 100        es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
 101        es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
 102        /* leave es->s_feature_*compat flags alone */
 103        /* es->s_uuid will be set by e2fsck if empty */
 104
 105        /*
 106         * The rest of the superblock fields should be zero, and if not it
 107         * means they are likely already in use, so leave them alone.  We
 108         * can leave it up to e2fsck to clean up any inconsistencies there.
 109         */
 110}
 111
 112static void ext2_put_super (struct super_block * sb)
 113{
 114        int db_count;
 115        int i;
 116        struct ext2_sb_info *sbi = EXT2_SB(sb);
 117
 118        lock_kernel();
 119
 120        if (sb->s_dirt)
 121                ext2_write_super(sb);
 122
 123        ext2_xattr_put_super(sb);
 124        if (!(sb->s_flags & MS_RDONLY)) {
 125                struct ext2_super_block *es = sbi->s_es;
 126
 127                es->s_state = cpu_to_le16(sbi->s_mount_state);
 128                ext2_sync_super(sb, es);
 129        }
 130        db_count = sbi->s_gdb_count;
 131        for (i = 0; i < db_count; i++)
 132                if (sbi->s_group_desc[i])
 133                        brelse (sbi->s_group_desc[i]);
 134        kfree(sbi->s_group_desc);
 135        kfree(sbi->s_debts);
 136        percpu_counter_destroy(&sbi->s_freeblocks_counter);
 137        percpu_counter_destroy(&sbi->s_freeinodes_counter);
 138        percpu_counter_destroy(&sbi->s_dirs_counter);
 139        brelse (sbi->s_sbh);
 140        sb->s_fs_info = NULL;
 141        kfree(sbi->s_blockgroup_lock);
 142        kfree(sbi);
 143
 144        unlock_kernel();
 145}
 146
 147static struct kmem_cache * ext2_inode_cachep;
 148
 149static struct inode *ext2_alloc_inode(struct super_block *sb)
 150{
 151        struct ext2_inode_info *ei;
 152        ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
 153        if (!ei)
 154                return NULL;
 155        ei->i_block_alloc_info = NULL;
 156        ei->vfs_inode.i_version = 1;
 157        return &ei->vfs_inode;
 158}
 159
 160static void ext2_destroy_inode(struct inode *inode)
 161{
 162        kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
 163}
 164
 165static void init_once(void *foo)
 166{
 167        struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
 168
 169        rwlock_init(&ei->i_meta_lock);
 170#ifdef CONFIG_EXT2_FS_XATTR
 171        init_rwsem(&ei->xattr_sem);
 172#endif
 173        mutex_init(&ei->truncate_mutex);
 174        inode_init_once(&ei->vfs_inode);
 175}
 176
 177static int init_inodecache(void)
 178{
 179        ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
 180                                             sizeof(struct ext2_inode_info),
 181                                             0, (SLAB_RECLAIM_ACCOUNT|
 182                                                SLAB_MEM_SPREAD),
 183                                             init_once);
 184        if (ext2_inode_cachep == NULL)
 185                return -ENOMEM;
 186        return 0;
 187}
 188
 189static void destroy_inodecache(void)
 190{
 191        kmem_cache_destroy(ext2_inode_cachep);
 192}
 193
 194static void ext2_clear_inode(struct inode *inode)
 195{
 196        struct ext2_block_alloc_info *rsv = EXT2_I(inode)->i_block_alloc_info;
 197        ext2_discard_reservation(inode);
 198        EXT2_I(inode)->i_block_alloc_info = NULL;
 199        if (unlikely(rsv))
 200                kfree(rsv);
 201}
 202
 203static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
 204{
 205        struct super_block *sb = vfs->mnt_sb;
 206        struct ext2_sb_info *sbi = EXT2_SB(sb);
 207        struct ext2_super_block *es = sbi->s_es;
 208        unsigned long def_mount_opts;
 209
 210        def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 211
 212        if (sbi->s_sb_block != 1)
 213                seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
 214        if (test_opt(sb, MINIX_DF))
 215                seq_puts(seq, ",minixdf");
 216        if (test_opt(sb, GRPID))
 217                seq_puts(seq, ",grpid");
 218        if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
 219                seq_puts(seq, ",nogrpid");
 220        if (sbi->s_resuid != EXT2_DEF_RESUID ||
 221            le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
 222                seq_printf(seq, ",resuid=%u", sbi->s_resuid);
 223        }
 224        if (sbi->s_resgid != EXT2_DEF_RESGID ||
 225            le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
 226                seq_printf(seq, ",resgid=%u", sbi->s_resgid);
 227        }
 228        if (test_opt(sb, ERRORS_RO)) {
 229                int def_errors = le16_to_cpu(es->s_errors);
 230
 231                if (def_errors == EXT2_ERRORS_PANIC ||
 232                    def_errors == EXT2_ERRORS_CONTINUE) {
 233                        seq_puts(seq, ",errors=remount-ro");
 234                }
 235        }
 236        if (test_opt(sb, ERRORS_CONT))
 237                seq_puts(seq, ",errors=continue");
 238        if (test_opt(sb, ERRORS_PANIC))
 239                seq_puts(seq, ",errors=panic");
 240        if (test_opt(sb, NO_UID32))
 241                seq_puts(seq, ",nouid32");
 242        if (test_opt(sb, DEBUG))
 243                seq_puts(seq, ",debug");
 244        if (test_opt(sb, OLDALLOC))
 245                seq_puts(seq, ",oldalloc");
 246
 247#ifdef CONFIG_EXT2_FS_XATTR
 248        if (test_opt(sb, XATTR_USER))
 249                seq_puts(seq, ",user_xattr");
 250        if (!test_opt(sb, XATTR_USER) &&
 251            (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
 252                seq_puts(seq, ",nouser_xattr");
 253        }
 254#endif
 255
 256#ifdef CONFIG_EXT2_FS_POSIX_ACL
 257        if (test_opt(sb, POSIX_ACL))
 258                seq_puts(seq, ",acl");
 259        if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
 260                seq_puts(seq, ",noacl");
 261#endif
 262
 263        if (test_opt(sb, NOBH))
 264                seq_puts(seq, ",nobh");
 265
 266#if defined(CONFIG_QUOTA)
 267        if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
 268                seq_puts(seq, ",usrquota");
 269
 270        if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
 271                seq_puts(seq, ",grpquota");
 272#endif
 273
 274#if defined(CONFIG_EXT2_FS_XIP)
 275        if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
 276                seq_puts(seq, ",xip");
 277#endif
 278
 279        if (!test_opt(sb, RESERVATION))
 280                seq_puts(seq, ",noreservation");
 281
 282        return 0;
 283}
 284
 285#ifdef CONFIG_QUOTA
 286static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
 287static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
 288#endif
 289
 290static const struct super_operations ext2_sops = {
 291        .alloc_inode    = ext2_alloc_inode,
 292        .destroy_inode  = ext2_destroy_inode,
 293        .write_inode    = ext2_write_inode,
 294        .delete_inode   = ext2_delete_inode,
 295        .put_super      = ext2_put_super,
 296        .write_super    = ext2_write_super,
 297        .sync_fs        = ext2_sync_fs,
 298        .statfs         = ext2_statfs,
 299        .remount_fs     = ext2_remount,
 300        .clear_inode    = ext2_clear_inode,
 301        .show_options   = ext2_show_options,
 302#ifdef CONFIG_QUOTA
 303        .quota_read     = ext2_quota_read,
 304        .quota_write    = ext2_quota_write,
 305#endif
 306};
 307
 308static struct inode *ext2_nfs_get_inode(struct super_block *sb,
 309                u64 ino, u32 generation)
 310{
 311        struct inode *inode;
 312
 313        if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
 314                return ERR_PTR(-ESTALE);
 315        if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
 316                return ERR_PTR(-ESTALE);
 317
 318        /* iget isn't really right if the inode is currently unallocated!!
 319         * ext2_read_inode currently does appropriate checks, but
 320         * it might be "neater" to call ext2_get_inode first and check
 321         * if the inode is valid.....
 322         */
 323        inode = ext2_iget(sb, ino);
 324        if (IS_ERR(inode))
 325                return ERR_CAST(inode);
 326        if (generation && inode->i_generation != generation) {
 327                /* we didn't find the right inode.. */
 328                iput(inode);
 329                return ERR_PTR(-ESTALE);
 330        }
 331        return inode;
 332}
 333
 334static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 335                int fh_len, int fh_type)
 336{
 337        return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 338                                    ext2_nfs_get_inode);
 339}
 340
 341static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
 342                int fh_len, int fh_type)
 343{
 344        return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 345                                    ext2_nfs_get_inode);
 346}
 347
 348/* Yes, most of these are left as NULL!!
 349 * A NULL value implies the default, which works with ext2-like file
 350 * systems, but can be improved upon.
 351 * Currently only get_parent is required.
 352 */
 353static const struct export_operations ext2_export_ops = {
 354        .fh_to_dentry = ext2_fh_to_dentry,
 355        .fh_to_parent = ext2_fh_to_parent,
 356        .get_parent = ext2_get_parent,
 357};
 358
 359static unsigned long get_sb_block(void **data)
 360{
 361        unsigned long   sb_block;
 362        char            *options = (char *) *data;
 363
 364        if (!options || strncmp(options, "sb=", 3) != 0)
 365                return 1;       /* Default location */
 366        options += 3;
 367        sb_block = simple_strtoul(options, &options, 0);
 368        if (*options && *options != ',') {
 369                printk("EXT2-fs: Invalid sb specification: %s\n",
 370                       (char *) *data);
 371                return 1;
 372        }
 373        if (*options == ',')
 374                options++;
 375        *data = (void *) options;
 376        return sb_block;
 377}
 378
 379enum {
 380        Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
 381        Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
 382        Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
 383        Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
 384        Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
 385        Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
 386};
 387
 388static const match_table_t tokens = {
 389        {Opt_bsd_df, "bsddf"},
 390        {Opt_minix_df, "minixdf"},
 391        {Opt_grpid, "grpid"},
 392        {Opt_grpid, "bsdgroups"},
 393        {Opt_nogrpid, "nogrpid"},
 394        {Opt_nogrpid, "sysvgroups"},
 395        {Opt_resgid, "resgid=%u"},
 396        {Opt_resuid, "resuid=%u"},
 397        {Opt_sb, "sb=%u"},
 398        {Opt_err_cont, "errors=continue"},
 399        {Opt_err_panic, "errors=panic"},
 400        {Opt_err_ro, "errors=remount-ro"},
 401        {Opt_nouid32, "nouid32"},
 402        {Opt_nocheck, "check=none"},
 403        {Opt_nocheck, "nocheck"},
 404        {Opt_debug, "debug"},
 405        {Opt_oldalloc, "oldalloc"},
 406        {Opt_orlov, "orlov"},
 407        {Opt_nobh, "nobh"},
 408        {Opt_user_xattr, "user_xattr"},
 409        {Opt_nouser_xattr, "nouser_xattr"},
 410        {Opt_acl, "acl"},
 411        {Opt_noacl, "noacl"},
 412        {Opt_xip, "xip"},
 413        {Opt_grpquota, "grpquota"},
 414        {Opt_ignore, "noquota"},
 415        {Opt_quota, "quota"},
 416        {Opt_usrquota, "usrquota"},
 417        {Opt_reservation, "reservation"},
 418        {Opt_noreservation, "noreservation"},
 419        {Opt_err, NULL}
 420};
 421
 422static int parse_options(char *options, struct super_block *sb)
 423{
 424        char *p;
 425        struct ext2_sb_info *sbi = EXT2_SB(sb);
 426        substring_t args[MAX_OPT_ARGS];
 427        int option;
 428
 429        if (!options)
 430                return 1;
 431
 432        while ((p = strsep (&options, ",")) != NULL) {
 433                int token;
 434                if (!*p)
 435                        continue;
 436
 437                token = match_token(p, tokens, args);
 438                switch (token) {
 439                case Opt_bsd_df:
 440                        clear_opt (sbi->s_mount_opt, MINIX_DF);
 441                        break;
 442                case Opt_minix_df:
 443                        set_opt (sbi->s_mount_opt, MINIX_DF);
 444                        break;
 445                case Opt_grpid:
 446                        set_opt (sbi->s_mount_opt, GRPID);
 447                        break;
 448                case Opt_nogrpid:
 449                        clear_opt (sbi->s_mount_opt, GRPID);
 450                        break;
 451                case Opt_resuid:
 452                        if (match_int(&args[0], &option))
 453                                return 0;
 454                        sbi->s_resuid = option;
 455                        break;
 456                case Opt_resgid:
 457                        if (match_int(&args[0], &option))
 458                                return 0;
 459                        sbi->s_resgid = option;
 460                        break;
 461                case Opt_sb:
 462                        /* handled by get_sb_block() instead of here */
 463                        /* *sb_block = match_int(&args[0]); */
 464                        break;
 465                case Opt_err_panic:
 466                        clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 467                        clear_opt (sbi->s_mount_opt, ERRORS_RO);
 468                        set_opt (sbi->s_mount_opt, ERRORS_PANIC);
 469                        break;
 470                case Opt_err_ro:
 471                        clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 472                        clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 473                        set_opt (sbi->s_mount_opt, ERRORS_RO);
 474                        break;
 475                case Opt_err_cont:
 476                        clear_opt (sbi->s_mount_opt, ERRORS_RO);
 477                        clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 478                        set_opt (sbi->s_mount_opt, ERRORS_CONT);
 479                        break;
 480                case Opt_nouid32:
 481                        set_opt (sbi->s_mount_opt, NO_UID32);
 482                        break;
 483                case Opt_nocheck:
 484                        clear_opt (sbi->s_mount_opt, CHECK);
 485                        break;
 486                case Opt_debug:
 487                        set_opt (sbi->s_mount_opt, DEBUG);
 488                        break;
 489                case Opt_oldalloc:
 490                        set_opt (sbi->s_mount_opt, OLDALLOC);
 491                        break;
 492                case Opt_orlov:
 493                        clear_opt (sbi->s_mount_opt, OLDALLOC);
 494                        break;
 495                case Opt_nobh:
 496                        set_opt (sbi->s_mount_opt, NOBH);
 497                        break;
 498#ifdef CONFIG_EXT2_FS_XATTR
 499                case Opt_user_xattr:
 500                        set_opt (sbi->s_mount_opt, XATTR_USER);
 501                        break;
 502                case Opt_nouser_xattr:
 503                        clear_opt (sbi->s_mount_opt, XATTR_USER);
 504                        break;
 505#else
 506                case Opt_user_xattr:
 507                case Opt_nouser_xattr:
 508                        ext2_msg(sb, KERN_INFO, "(no)user_xattr options"
 509                                "not supported");
 510                        break;
 511#endif
 512#ifdef CONFIG_EXT2_FS_POSIX_ACL
 513                case Opt_acl:
 514                        set_opt(sbi->s_mount_opt, POSIX_ACL);
 515                        break;
 516                case Opt_noacl:
 517                        clear_opt(sbi->s_mount_opt, POSIX_ACL);
 518                        break;
 519#else
 520                case Opt_acl:
 521                case Opt_noacl:
 522                        ext2_msg(sb, KERN_INFO,
 523                                "(no)acl options not supported");
 524                        break;
 525#endif
 526                case Opt_xip:
 527#ifdef CONFIG_EXT2_FS_XIP
 528                        set_opt (sbi->s_mount_opt, XIP);
 529#else
 530                        ext2_msg(sb, KERN_INFO, "xip option not supported");
 531#endif
 532                        break;
 533
 534#if defined(CONFIG_QUOTA)
 535                case Opt_quota:
 536                case Opt_usrquota:
 537                        set_opt(sbi->s_mount_opt, USRQUOTA);
 538                        break;
 539
 540                case Opt_grpquota:
 541                        set_opt(sbi->s_mount_opt, GRPQUOTA);
 542                        break;
 543#else
 544                case Opt_quota:
 545                case Opt_usrquota:
 546                case Opt_grpquota:
 547                        ext2_msg(sb, KERN_INFO,
 548                                "quota operations not supported");
 549                        break;
 550#endif
 551
 552                case Opt_reservation:
 553                        set_opt(sbi->s_mount_opt, RESERVATION);
 554                        ext2_msg(sb, KERN_INFO, "reservations ON");
 555                        break;
 556                case Opt_noreservation:
 557                        clear_opt(sbi->s_mount_opt, RESERVATION);
 558                        ext2_msg(sb, KERN_INFO, "reservations OFF");
 559                        break;
 560                case Opt_ignore:
 561                        break;
 562                default:
 563                        return 0;
 564                }
 565        }
 566        return 1;
 567}
 568
 569static int ext2_setup_super (struct super_block * sb,
 570                              struct ext2_super_block * es,
 571                              int read_only)
 572{
 573        int res = 0;
 574        struct ext2_sb_info *sbi = EXT2_SB(sb);
 575
 576        if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 577                ext2_msg(sb, KERN_ERR,
 578                        "error: revision level too high, "
 579                        "forcing read-only mode");
 580                res = MS_RDONLY;
 581        }
 582        if (read_only)
 583                return res;
 584        if (!(sbi->s_mount_state & EXT2_VALID_FS))
 585                ext2_msg(sb, KERN_WARNING,
 586                        "warning: mounting unchecked fs, "
 587                        "running e2fsck is recommended");
 588        else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 589                ext2_msg(sb, KERN_WARNING,
 590                        "warning: mounting fs with errors, "
 591                        "running e2fsck is recommended");
 592        else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 593                 le16_to_cpu(es->s_mnt_count) >=
 594                 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 595                ext2_msg(sb, KERN_WARNING,
 596                        "warning: maximal mount count reached, "
 597                        "running e2fsck is recommended");
 598        else if (le32_to_cpu(es->s_checkinterval) &&
 599                (le32_to_cpu(es->s_lastcheck) +
 600                        le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 601                ext2_msg(sb, KERN_WARNING,
 602                        "warning: checktime reached, "
 603                        "running e2fsck is recommended");
 604        if (!le16_to_cpu(es->s_max_mnt_count))
 605                es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 606        le16_add_cpu(&es->s_mnt_count, 1);
 607        ext2_write_super(sb);
 608        if (test_opt (sb, DEBUG))
 609                ext2_msg(sb, KERN_INFO, "%s, %s, bs=%lu, fs=%lu, gc=%lu, "
 610                        "bpg=%lu, ipg=%lu, mo=%04lx]",
 611                        EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 612                        sbi->s_frag_size,
 613                        sbi->s_groups_count,
 614                        EXT2_BLOCKS_PER_GROUP(sb),
 615                        EXT2_INODES_PER_GROUP(sb),
 616                        sbi->s_mount_opt);
 617        return res;
 618}
 619
 620static int ext2_check_descriptors(struct super_block *sb)
 621{
 622        int i;
 623        struct ext2_sb_info *sbi = EXT2_SB(sb);
 624
 625        ext2_debug ("Checking group descriptors");
 626
 627        for (i = 0; i < sbi->s_groups_count; i++) {
 628                struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
 629                ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
 630                ext2_fsblk_t last_block;
 631
 632                if (i == sbi->s_groups_count - 1)
 633                        last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
 634                else
 635                        last_block = first_block +
 636                                (EXT2_BLOCKS_PER_GROUP(sb) - 1);
 637
 638                if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
 639                    le32_to_cpu(gdp->bg_block_bitmap) > last_block)
 640                {
 641                        ext2_error (sb, "ext2_check_descriptors",
 642                                    "Block bitmap for group %d"
 643                                    " not in group (block %lu)!",
 644                                    i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 645                        return 0;
 646                }
 647                if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
 648                    le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
 649                {
 650                        ext2_error (sb, "ext2_check_descriptors",
 651                                    "Inode bitmap for group %d"
 652                                    " not in group (block %lu)!",
 653                                    i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 654                        return 0;
 655                }
 656                if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
 657                    le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
 658                    last_block)
 659                {
 660                        ext2_error (sb, "ext2_check_descriptors",
 661                                    "Inode table for group %d"
 662                                    " not in group (block %lu)!",
 663                                    i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 664                        return 0;
 665                }
 666        }
 667        return 1;
 668}
 669
 670/*
 671 * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 672 * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 673 * We need to be 1 filesystem block less than the 2^32 sector limit.
 674 */
 675static loff_t ext2_max_size(int bits)
 676{
 677        loff_t res = EXT2_NDIR_BLOCKS;
 678        int meta_blocks;
 679        loff_t upper_limit;
 680
 681        /* This is calculated to be the largest file size for a
 682         * dense, file such that the total number of
 683         * sectors in the file, including data and all indirect blocks,
 684         * does not exceed 2^32 -1
 685         * __u32 i_blocks representing the total number of
 686         * 512 bytes blocks of the file
 687         */
 688        upper_limit = (1LL << 32) - 1;
 689
 690        /* total blocks in file system block size */
 691        upper_limit >>= (bits - 9);
 692
 693
 694        /* indirect blocks */
 695        meta_blocks = 1;
 696        /* double indirect blocks */
 697        meta_blocks += 1 + (1LL << (bits-2));
 698        /* tripple indirect blocks */
 699        meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
 700
 701        upper_limit -= meta_blocks;
 702        upper_limit <<= bits;
 703
 704        res += 1LL << (bits-2);
 705        res += 1LL << (2*(bits-2));
 706        res += 1LL << (3*(bits-2));
 707        res <<= bits;
 708        if (res > upper_limit)
 709                res = upper_limit;
 710
 711        if (res > MAX_LFS_FILESIZE)
 712                res = MAX_LFS_FILESIZE;
 713
 714        return res;
 715}
 716
 717static unsigned long descriptor_loc(struct super_block *sb,
 718                                    unsigned long logic_sb_block,
 719                                    int nr)
 720{
 721        struct ext2_sb_info *sbi = EXT2_SB(sb);
 722        unsigned long bg, first_meta_bg;
 723        int has_super = 0;
 724        
 725        first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 726
 727        if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 728            nr < first_meta_bg)
 729                return (logic_sb_block + nr + 1);
 730        bg = sbi->s_desc_per_block * nr;
 731        if (ext2_bg_has_super(sb, bg))
 732                has_super = 1;
 733
 734        return ext2_group_first_block_no(sb, bg) + has_super;
 735}
 736
 737static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 738{
 739        struct buffer_head * bh;
 740        struct ext2_sb_info * sbi;
 741        struct ext2_super_block * es;
 742        struct inode *root;
 743        unsigned long block;
 744        unsigned long sb_block = get_sb_block(&data);
 745        unsigned long logic_sb_block;
 746        unsigned long offset = 0;
 747        unsigned long def_mount_opts;
 748        long ret = -EINVAL;
 749        int blocksize = BLOCK_SIZE;
 750        int db_count;
 751        int i, j;
 752        __le32 features;
 753        int err;
 754
 755        sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 756        if (!sbi)
 757                return -ENOMEM;
 758
 759        sbi->s_blockgroup_lock =
 760                kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
 761        if (!sbi->s_blockgroup_lock) {
 762                kfree(sbi);
 763                return -ENOMEM;
 764        }
 765        sb->s_fs_info = sbi;
 766        sbi->s_sb_block = sb_block;
 767
 768        /*
 769         * See what the current blocksize for the device is, and
 770         * use that as the blocksize.  Otherwise (or if the blocksize
 771         * is smaller than the default) use the default.
 772         * This is important for devices that have a hardware
 773         * sectorsize that is larger than the default.
 774         */
 775        blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 776        if (!blocksize) {
 777                ext2_msg(sb, KERN_ERR, "error: unable to set blocksize");
 778                goto failed_sbi;
 779        }
 780
 781        /*
 782         * If the superblock doesn't start on a hardware sector boundary,
 783         * calculate the offset.  
 784         */
 785        if (blocksize != BLOCK_SIZE) {
 786                logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 787                offset = (sb_block*BLOCK_SIZE) % blocksize;
 788        } else {
 789                logic_sb_block = sb_block;
 790        }
 791
 792        if (!(bh = sb_bread(sb, logic_sb_block))) {
 793                ext2_msg(sb, KERN_ERR, "error: unable to read superblock");
 794                goto failed_sbi;
 795        }
 796        /*
 797         * Note: s_es must be initialized as soon as possible because
 798         *       some ext2 macro-instructions depend on its value
 799         */
 800        es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 801        sbi->s_es = es;
 802        sb->s_magic = le16_to_cpu(es->s_magic);
 803
 804        if (sb->s_magic != EXT2_SUPER_MAGIC)
 805                goto cantfind_ext2;
 806
 807        /* Set defaults before we parse the mount options */
 808        def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 809        if (def_mount_opts & EXT2_DEFM_DEBUG)
 810                set_opt(sbi->s_mount_opt, DEBUG);
 811        if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 812                set_opt(sbi->s_mount_opt, GRPID);
 813        if (def_mount_opts & EXT2_DEFM_UID16)
 814                set_opt(sbi->s_mount_opt, NO_UID32);
 815#ifdef CONFIG_EXT2_FS_XATTR
 816        if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 817                set_opt(sbi->s_mount_opt, XATTR_USER);
 818#endif
 819#ifdef CONFIG_EXT2_FS_POSIX_ACL
 820        if (def_mount_opts & EXT2_DEFM_ACL)
 821                set_opt(sbi->s_mount_opt, POSIX_ACL);
 822#endif
 823        
 824        if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 825                set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 826        else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
 827                set_opt(sbi->s_mount_opt, ERRORS_CONT);
 828        else
 829                set_opt(sbi->s_mount_opt, ERRORS_RO);
 830
 831        sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
 832        sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
 833        
 834        set_opt(sbi->s_mount_opt, RESERVATION);
 835
 836        if (!parse_options((char *) data, sb))
 837                goto failed_mount;
 838
 839        sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 840                ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 841                 MS_POSIXACL : 0);
 842
 843        ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
 844                                    EXT2_MOUNT_XIP if not */
 845
 846        if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 847            (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 848             EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 849             EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 850                ext2_msg(sb, KERN_WARNING,
 851                        "warning: feature flags set on rev 0 fs, "
 852                        "running e2fsck is recommended");
 853        /*
 854         * Check feature flags regardless of the revision level, since we
 855         * previously didn't change the revision level when setting the flags,
 856         * so there is a chance incompat flags are set on a rev 0 filesystem.
 857         */
 858        features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 859        if (features) {
 860                ext2_msg(sb, KERN_ERR,  "error: couldn't mount because of "
 861                       "unsupported optional features (%x)",
 862                        le32_to_cpu(features));
 863                goto failed_mount;
 864        }
 865        if (!(sb->s_flags & MS_RDONLY) &&
 866            (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 867                ext2_msg(sb, KERN_ERR, "error: couldn't mount RDWR because of "
 868                       "unsupported optional features (%x)",
 869                       le32_to_cpu(features));
 870                goto failed_mount;
 871        }
 872
 873        blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 874
 875        if (ext2_use_xip(sb) && blocksize != PAGE_SIZE) {
 876                if (!silent)
 877                        ext2_msg(sb, KERN_ERR,
 878                                "error: unsupported blocksize for xip");
 879                goto failed_mount;
 880        }
 881
 882        /* If the blocksize doesn't match, re-read the thing.. */
 883        if (sb->s_blocksize != blocksize) {
 884                brelse(bh);
 885
 886                if (!sb_set_blocksize(sb, blocksize)) {
 887                        ext2_msg(sb, KERN_ERR, "error: blocksize is too small");
 888                        goto failed_sbi;
 889                }
 890
 891                logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 892                offset = (sb_block*BLOCK_SIZE) % blocksize;
 893                bh = sb_bread(sb, logic_sb_block);
 894                if(!bh) {
 895                        ext2_msg(sb, KERN_ERR, "error: couldn't read"
 896                                "superblock on 2nd try");
 897                        goto failed_sbi;
 898                }
 899                es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 900                sbi->s_es = es;
 901                if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 902                        ext2_msg(sb, KERN_ERR, "error: magic mismatch");
 903                        goto failed_mount;
 904                }
 905        }
 906
 907        sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 908
 909        if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 910                sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 911                sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 912        } else {
 913                sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 914                sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 915                if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 916                    !is_power_of_2(sbi->s_inode_size) ||
 917                    (sbi->s_inode_size > blocksize)) {
 918                        ext2_msg(sb, KERN_ERR,
 919                                "error: unsupported inode size: %d",
 920                                sbi->s_inode_size);
 921                        goto failed_mount;
 922                }
 923        }
 924
 925        sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 926                                   le32_to_cpu(es->s_log_frag_size);
 927        if (sbi->s_frag_size == 0)
 928                goto cantfind_ext2;
 929        sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
 930
 931        sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 932        sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 933        sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 934
 935        if (EXT2_INODE_SIZE(sb) == 0)
 936                goto cantfind_ext2;
 937        sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
 938        if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
 939                goto cantfind_ext2;
 940        sbi->s_itb_per_group = sbi->s_inodes_per_group /
 941                                        sbi->s_inodes_per_block;
 942        sbi->s_desc_per_block = sb->s_blocksize /
 943                                        sizeof (struct ext2_group_desc);
 944        sbi->s_sbh = bh;
 945        sbi->s_mount_state = le16_to_cpu(es->s_state);
 946        sbi->s_addr_per_block_bits =
 947                ilog2 (EXT2_ADDR_PER_BLOCK(sb));
 948        sbi->s_desc_per_block_bits =
 949                ilog2 (EXT2_DESC_PER_BLOCK(sb));
 950
 951        if (sb->s_magic != EXT2_SUPER_MAGIC)
 952                goto cantfind_ext2;
 953
 954        if (sb->s_blocksize != bh->b_size) {
 955                if (!silent)
 956                        ext2_msg(sb, KERN_ERR, "error: unsupported blocksize");
 957                goto failed_mount;
 958        }
 959
 960        if (sb->s_blocksize != sbi->s_frag_size) {
 961                ext2_msg(sb, KERN_ERR,
 962                        "error: fragsize %lu != blocksize %lu"
 963                        "(not supported yet)",
 964                        sbi->s_frag_size, sb->s_blocksize);
 965                goto failed_mount;
 966        }
 967
 968        if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
 969                ext2_msg(sb, KERN_ERR,
 970                        "error: #blocks per group too big: %lu",
 971                        sbi->s_blocks_per_group);
 972                goto failed_mount;
 973        }
 974        if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 975                ext2_msg(sb, KERN_ERR,
 976                        "error: #fragments per group too big: %lu",
 977                        sbi->s_frags_per_group);
 978                goto failed_mount;
 979        }
 980        if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
 981                ext2_msg(sb, KERN_ERR,
 982                        "error: #inodes per group too big: %lu",
 983                        sbi->s_inodes_per_group);
 984                goto failed_mount;
 985        }
 986
 987        if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
 988                goto cantfind_ext2;
 989        sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
 990                                le32_to_cpu(es->s_first_data_block) - 1)
 991                                        / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
 992        db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
 993                   EXT2_DESC_PER_BLOCK(sb);
 994        sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
 995        if (sbi->s_group_desc == NULL) {
 996                ext2_msg(sb, KERN_ERR, "error: not enough memory");
 997                goto failed_mount;
 998        }
 999        bgl_lock_init(sbi->s_blockgroup_lock);
1000        sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
1001        if (!sbi->s_debts) {
1002                ext2_msg(sb, KERN_ERR, "error: not enough memory");
1003                goto failed_mount_group_desc;
1004        }
1005        for (i = 0; i < db_count; i++) {
1006                block = descriptor_loc(sb, logic_sb_block, i);
1007                sbi->s_group_desc[i] = sb_bread(sb, block);
1008                if (!sbi->s_group_desc[i]) {
1009                        for (j = 0; j < i; j++)
1010                                brelse (sbi->s_group_desc[j]);
1011                        ext2_msg(sb, KERN_ERR,
1012                                "error: unable to read group descriptors");
1013                        goto failed_mount_group_desc;
1014                }
1015        }
1016        if (!ext2_check_descriptors (sb)) {
1017                ext2_msg(sb, KERN_ERR, "group descriptors corrupted");
1018                goto failed_mount2;
1019        }
1020        sbi->s_gdb_count = db_count;
1021        get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1022        spin_lock_init(&sbi->s_next_gen_lock);
1023
1024        /* per fileystem reservation list head & lock */
1025        spin_lock_init(&sbi->s_rsv_window_lock);
1026        sbi->s_rsv_window_root = RB_ROOT;
1027        /*
1028         * Add a single, static dummy reservation to the start of the
1029         * reservation window list --- it gives us a placeholder for
1030         * append-at-start-of-list which makes the allocation logic
1031         * _much_ simpler.
1032         */
1033        sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1034        sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1035        sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1036        sbi->s_rsv_window_head.rsv_goal_size = 0;
1037        ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1038
1039        err = percpu_counter_init(&sbi->s_freeblocks_counter,
1040                                ext2_count_free_blocks(sb));
1041        if (!err) {
1042                err = percpu_counter_init(&sbi->s_freeinodes_counter,
1043                                ext2_count_free_inodes(sb));
1044        }
1045        if (!err) {
1046                err = percpu_counter_init(&sbi->s_dirs_counter,
1047                                ext2_count_dirs(sb));
1048        }
1049        if (err) {
1050                ext2_msg(sb, KERN_ERR, "error: insufficient memory");
1051                goto failed_mount3;
1052        }
1053        /*
1054         * set up enough so that it can read an inode
1055         */
1056        sb->s_op = &ext2_sops;
1057        sb->s_export_op = &ext2_export_ops;
1058        sb->s_xattr = ext2_xattr_handlers;
1059        root = ext2_iget(sb, EXT2_ROOT_INO);
1060        if (IS_ERR(root)) {
1061                ret = PTR_ERR(root);
1062                goto failed_mount3;
1063        }
1064        if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1065                iput(root);
1066                ext2_msg(sb, KERN_ERR, "error: corrupt root inode, run e2fsck");
1067                goto failed_mount3;
1068        }
1069
1070        sb->s_root = d_alloc_root(root);
1071        if (!sb->s_root) {
1072                iput(root);
1073                ext2_msg(sb, KERN_ERR, "error: get root inode failed");
1074                ret = -ENOMEM;
1075                goto failed_mount3;
1076        }
1077        if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1078                ext2_msg(sb, KERN_WARNING,
1079                        "warning: mounting ext3 filesystem as ext2");
1080        ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
1081        return 0;
1082
1083cantfind_ext2:
1084        if (!silent)
1085                ext2_msg(sb, KERN_ERR,
1086                        "error: can't find an ext2 filesystem on dev %s.",
1087                        sb->s_id);
1088        goto failed_mount;
1089failed_mount3:
1090        percpu_counter_destroy(&sbi->s_freeblocks_counter);
1091        percpu_counter_destroy(&sbi->s_freeinodes_counter);
1092        percpu_counter_destroy(&sbi->s_dirs_counter);
1093failed_mount2:
1094        for (i = 0; i < db_count; i++)
1095                brelse(sbi->s_group_desc[i]);
1096failed_mount_group_desc:
1097        kfree(sbi->s_group_desc);
1098        kfree(sbi->s_debts);
1099failed_mount:
1100        brelse(bh);
1101failed_sbi:
1102        sb->s_fs_info = NULL;
1103        kfree(sbi->s_blockgroup_lock);
1104        kfree(sbi);
1105        return ret;
1106}
1107
1108static void ext2_clear_super_error(struct super_block *sb)
1109{
1110        struct buffer_head *sbh = EXT2_SB(sb)->s_sbh;
1111
1112        if (buffer_write_io_error(sbh)) {
1113                /*
1114                 * Oh, dear.  A previous attempt to write the
1115                 * superblock failed.  This could happen because the
1116                 * USB device was yanked out.  Or it could happen to
1117                 * be a transient write error and maybe the block will
1118                 * be remapped.  Nothing we can do but to retry the
1119                 * write and hope for the best.
1120                 */
1121                printk(KERN_ERR "EXT2-fs: %s previous I/O error to "
1122                       "superblock detected", sb->s_id);
1123                clear_buffer_write_io_error(sbh);
1124                set_buffer_uptodate(sbh);
1125        }
1126}
1127
1128static void ext2_commit_super (struct super_block * sb,
1129                               struct ext2_super_block * es)
1130{
1131        ext2_clear_super_error(sb);
1132        es->s_wtime = cpu_to_le32(get_seconds());
1133        mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1134        sb->s_dirt = 0;
1135}
1136
1137static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
1138{
1139        ext2_clear_super_error(sb);
1140        es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1141        es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1142        es->s_wtime = cpu_to_le32(get_seconds());
1143        mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1144        sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1145        sb->s_dirt = 0;
1146}
1147
1148/*
1149 * In the second extended file system, it is not necessary to
1150 * write the super block since we use a mapping of the
1151 * disk super block in a buffer.
1152 *
1153 * However, this function is still used to set the fs valid
1154 * flags to 0.  We need to set this flag to 0 since the fs
1155 * may have been checked while mounted and e2fsck may have
1156 * set s_state to EXT2_VALID_FS after some corrections.
1157 */
1158
1159static int ext2_sync_fs(struct super_block *sb, int wait)
1160{
1161        struct ext2_super_block *es = EXT2_SB(sb)->s_es;
1162        struct buffer_head *sbh = EXT2_SB(sb)->s_sbh;
1163
1164        lock_kernel();
1165        if (buffer_write_io_error(sbh)) {
1166                /*
1167                 * Oh, dear.  A previous attempt to write the
1168                 * superblock failed.  This could happen because the
1169                 * USB device was yanked out.  Or it could happen to
1170                 * be a transient write error and maybe the block will
1171                 * be remapped.  Nothing we can do but to retry the
1172                 * write and hope for the best.
1173                 */
1174                ext2_msg(sb, KERN_ERR,
1175                       "previous I/O error to superblock detected\n");
1176                clear_buffer_write_io_error(sbh);
1177                set_buffer_uptodate(sbh);
1178        }
1179
1180        if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1181                ext2_debug("setting valid to 0\n");
1182                es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1183                es->s_free_blocks_count =
1184                        cpu_to_le32(ext2_count_free_blocks(sb));
1185                es->s_free_inodes_count =
1186                        cpu_to_le32(ext2_count_free_inodes(sb));
1187                es->s_mtime = cpu_to_le32(get_seconds());
1188                ext2_sync_super(sb, es);
1189        } else {
1190                ext2_commit_super(sb, es);
1191        }
1192        sb->s_dirt = 0;
1193        unlock_kernel();
1194
1195        return 0;
1196}
1197
1198
1199void ext2_write_super(struct super_block *sb)
1200{
1201        if (!(sb->s_flags & MS_RDONLY))
1202                ext2_sync_fs(sb, 1);
1203        else
1204                sb->s_dirt = 0;
1205}
1206
1207static int ext2_remount (struct super_block * sb, int * flags, char * data)
1208{
1209        struct ext2_sb_info * sbi = EXT2_SB(sb);
1210        struct ext2_super_block * es;
1211        unsigned long old_mount_opt = sbi->s_mount_opt;
1212        struct ext2_mount_options old_opts;
1213        unsigned long old_sb_flags;
1214        int err;
1215
1216        lock_kernel();
1217
1218        /* Store the old options */
1219        old_sb_flags = sb->s_flags;
1220        old_opts.s_mount_opt = sbi->s_mount_opt;
1221        old_opts.s_resuid = sbi->s_resuid;
1222        old_opts.s_resgid = sbi->s_resgid;
1223
1224        /*
1225         * Allow the "check" option to be passed as a remount option.
1226         */
1227        if (!parse_options(data, sb)) {
1228                err = -EINVAL;
1229                goto restore_opts;
1230        }
1231
1232        sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1233                ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1234
1235        ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
1236                                    EXT2_MOUNT_XIP if not */
1237
1238        if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
1239                ext2_msg(sb, KERN_WARNING,
1240                        "warning: unsupported blocksize for xip");
1241                err = -EINVAL;
1242                goto restore_opts;
1243        }
1244
1245        es = sbi->s_es;
1246        if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
1247            (old_mount_opt & EXT2_MOUNT_XIP)) &&
1248            invalidate_inodes(sb)) {
1249                ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
1250                         "xip flag with busy inodes while remounting");
1251                sbi->s_mount_opt &= ~EXT2_MOUNT_XIP;
1252                sbi->s_mount_opt |= old_mount_opt & EXT2_MOUNT_XIP;
1253        }
1254        if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
1255                unlock_kernel();
1256                return 0;
1257        }
1258        if (*flags & MS_RDONLY) {
1259                if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1260                    !(sbi->s_mount_state & EXT2_VALID_FS)) {
1261                        unlock_kernel();
1262                        return 0;
1263                }
1264                /*
1265                 * OK, we are remounting a valid rw partition rdonly, so set
1266                 * the rdonly flag and then mark the partition as valid again.
1267                 */
1268                es->s_state = cpu_to_le16(sbi->s_mount_state);
1269                es->s_mtime = cpu_to_le32(get_seconds());
1270        } else {
1271                __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1272                                               ~EXT2_FEATURE_RO_COMPAT_SUPP);
1273                if (ret) {
1274                        ext2_msg(sb, KERN_WARNING,
1275                                "warning: couldn't remount RDWR because of "
1276                                "unsupported optional features (%x).",
1277                                le32_to_cpu(ret));
1278                        err = -EROFS;
1279                        goto restore_opts;
1280                }
1281                /*
1282                 * Mounting a RDONLY partition read-write, so reread and
1283                 * store the current valid flag.  (It may have been changed
1284                 * by e2fsck since we originally mounted the partition.)
1285                 */
1286                sbi->s_mount_state = le16_to_cpu(es->s_state);
1287                if (!ext2_setup_super (sb, es, 0))
1288                        sb->s_flags &= ~MS_RDONLY;
1289        }
1290        ext2_sync_super(sb, es);
1291        unlock_kernel();
1292        return 0;
1293restore_opts:
1294        sbi->s_mount_opt = old_opts.s_mount_opt;
1295        sbi->s_resuid = old_opts.s_resuid;
1296        sbi->s_resgid = old_opts.s_resgid;
1297        sb->s_flags = old_sb_flags;
1298        unlock_kernel();
1299        return err;
1300}
1301
1302static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1303{
1304        struct super_block *sb = dentry->d_sb;
1305        struct ext2_sb_info *sbi = EXT2_SB(sb);
1306        struct ext2_super_block *es = sbi->s_es;
1307        u64 fsid;
1308
1309        if (test_opt (sb, MINIX_DF))
1310                sbi->s_overhead_last = 0;
1311        else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1312                unsigned long i, overhead = 0;
1313                smp_rmb();
1314
1315                /*
1316                 * Compute the overhead (FS structures). This is constant
1317                 * for a given filesystem unless the number of block groups
1318                 * changes so we cache the previous value until it does.
1319                 */
1320
1321                /*
1322                 * All of the blocks before first_data_block are
1323                 * overhead
1324                 */
1325                overhead = le32_to_cpu(es->s_first_data_block);
1326
1327                /*
1328                 * Add the overhead attributed to the superblock and
1329                 * block group descriptors.  If the sparse superblocks
1330                 * feature is turned on, then not all groups have this.
1331                 */
1332                for (i = 0; i < sbi->s_groups_count; i++)
1333                        overhead += ext2_bg_has_super(sb, i) +
1334                                ext2_bg_num_gdb(sb, i);
1335
1336                /*
1337                 * Every block group has an inode bitmap, a block
1338                 * bitmap, and an inode table.
1339                 */
1340                overhead += (sbi->s_groups_count *
1341                             (2 + sbi->s_itb_per_group));
1342                sbi->s_overhead_last = overhead;
1343                smp_wmb();
1344                sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1345        }
1346
1347        buf->f_type = EXT2_SUPER_MAGIC;
1348        buf->f_bsize = sb->s_blocksize;
1349        buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1350        buf->f_bfree = ext2_count_free_blocks(sb);
1351        es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1352        buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1353        if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1354                buf->f_bavail = 0;
1355        buf->f_files = le32_to_cpu(es->s_inodes_count);
1356        buf->f_ffree = ext2_count_free_inodes(sb);
1357        es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1358        buf->f_namelen = EXT2_NAME_LEN;
1359        fsid = le64_to_cpup((void *)es->s_uuid) ^
1360               le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1361        buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1362        buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1363        return 0;
1364}
1365
1366static int ext2_get_sb(struct file_system_type *fs_type,
1367        int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1368{
1369        return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super, mnt);
1370}
1371
1372#ifdef CONFIG_QUOTA
1373
1374/* Read data from quotafile - avoid pagecache and such because we cannot afford
1375 * acquiring the locks... As quota files are never truncated and quota code
1376 * itself serializes the operations (and noone else should touch the files)
1377 * we don't have to be afraid of races */
1378static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1379                               size_t len, loff_t off)
1380{
1381        struct inode *inode = sb_dqopt(sb)->files[type];
1382        sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1383        int err = 0;
1384        int offset = off & (sb->s_blocksize - 1);
1385        int tocopy;
1386        size_t toread;
1387        struct buffer_head tmp_bh;
1388        struct buffer_head *bh;
1389        loff_t i_size = i_size_read(inode);
1390
1391        if (off > i_size)
1392                return 0;
1393        if (off+len > i_size)
1394                len = i_size-off;
1395        toread = len;
1396        while (toread > 0) {
1397                tocopy = sb->s_blocksize - offset < toread ?
1398                                sb->s_blocksize - offset : toread;
1399
1400                tmp_bh.b_state = 0;
1401                tmp_bh.b_size = sb->s_blocksize;
1402                err = ext2_get_block(inode, blk, &tmp_bh, 0);
1403                if (err < 0)
1404                        return err;
1405                if (!buffer_mapped(&tmp_bh))    /* A hole? */
1406                        memset(data, 0, tocopy);
1407                else {
1408                        bh = sb_bread(sb, tmp_bh.b_blocknr);
1409                        if (!bh)
1410                                return -EIO;
1411                        memcpy(data, bh->b_data+offset, tocopy);
1412                        brelse(bh);
1413                }
1414                offset = 0;
1415                toread -= tocopy;
1416                data += tocopy;
1417                blk++;
1418        }
1419        return len;
1420}
1421
1422/* Write to quotafile */
1423static ssize_t ext2_quota_write(struct super_block *sb, int type,
1424                                const char *data, size_t len, loff_t off)
1425{
1426        struct inode *inode = sb_dqopt(sb)->files[type];
1427        sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1428        int err = 0;
1429        int offset = off & (sb->s_blocksize - 1);
1430        int tocopy;
1431        size_t towrite = len;
1432        struct buffer_head tmp_bh;
1433        struct buffer_head *bh;
1434
1435        mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1436        while (towrite > 0) {
1437                tocopy = sb->s_blocksize - offset < towrite ?
1438                                sb->s_blocksize - offset : towrite;
1439
1440                tmp_bh.b_state = 0;
1441                err = ext2_get_block(inode, blk, &tmp_bh, 1);
1442                if (err < 0)
1443                        goto out;
1444                if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1445                        bh = sb_bread(sb, tmp_bh.b_blocknr);
1446                else
1447                        bh = sb_getblk(sb, tmp_bh.b_blocknr);
1448                if (!bh) {
1449                        err = -EIO;
1450                        goto out;
1451                }
1452                lock_buffer(bh);
1453                memcpy(bh->b_data+offset, data, tocopy);
1454                flush_dcache_page(bh->b_page);
1455                set_buffer_uptodate(bh);
1456                mark_buffer_dirty(bh);
1457                unlock_buffer(bh);
1458                brelse(bh);
1459                offset = 0;
1460                towrite -= tocopy;
1461                data += tocopy;
1462                blk++;
1463        }
1464out:
1465        if (len == towrite) {
1466                mutex_unlock(&inode->i_mutex);
1467                return err;
1468        }
1469        if (inode->i_size < off+len-towrite)
1470                i_size_write(inode, off+len-towrite);
1471        inode->i_version++;
1472        inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1473        mark_inode_dirty(inode);
1474        mutex_unlock(&inode->i_mutex);
1475        return len - towrite;
1476}
1477
1478#endif
1479
1480static struct file_system_type ext2_fs_type = {
1481        .owner          = THIS_MODULE,
1482        .name           = "ext2",
1483        .get_sb         = ext2_get_sb,
1484        .kill_sb        = kill_block_super,
1485        .fs_flags       = FS_REQUIRES_DEV,
1486};
1487
1488static int __init init_ext2_fs(void)
1489{
1490        int err = init_ext2_xattr();
1491        if (err)
1492                return err;
1493        err = init_inodecache();
1494        if (err)
1495                goto out1;
1496        err = register_filesystem(&ext2_fs_type);
1497        if (err)
1498                goto out;
1499        return 0;
1500out:
1501        destroy_inodecache();
1502out1:
1503        exit_ext2_xattr();
1504        return err;
1505}
1506
1507static void __exit exit_ext2_fs(void)
1508{
1509        unregister_filesystem(&ext2_fs_type);
1510        destroy_inodecache();
1511        exit_ext2_xattr();
1512}
1513
1514module_init(init_ext2_fs)
1515module_exit(exit_ext2_fs)
1516
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