linux/fs/affs/super.c
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   1/*
   2 *  linux/fs/affs/inode.c
   3 *
   4 *  (c) 1996  Hans-Joachim Widmaier - Rewritten
   5 *
   6 *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
   7 *
   8 *  (C) 1992  Eric Youngdale Modified for ISO 9660 filesystem.
   9 *
  10 *  (C) 1991  Linus Torvalds - minix filesystem
  11 */
  12
  13#include <linux/module.h>
  14#include <linux/init.h>
  15#include <linux/statfs.h>
  16#include <linux/parser.h>
  17#include <linux/magic.h>
  18#include <linux/sched.h>
  19#include <linux/slab.h>
  20#include <linux/writeback.h>
  21#include "affs.h"
  22
  23extern struct timezone sys_tz;
  24
  25static int affs_statfs(struct dentry *dentry, struct kstatfs *buf);
  26static int affs_remount (struct super_block *sb, int *flags, char *data);
  27
  28static void
  29affs_commit_super(struct super_block *sb, int wait)
  30{
  31        struct affs_sb_info *sbi = AFFS_SB(sb);
  32        struct buffer_head *bh = sbi->s_root_bh;
  33        struct affs_root_tail *tail = AFFS_ROOT_TAIL(sb, bh);
  34
  35        lock_buffer(bh);
  36        secs_to_datestamp(get_seconds(), &tail->disk_change);
  37        affs_fix_checksum(sb, bh);
  38        unlock_buffer(bh);
  39
  40        mark_buffer_dirty(bh);
  41        if (wait)
  42                sync_dirty_buffer(bh);
  43}
  44
  45static void
  46affs_put_super(struct super_block *sb)
  47{
  48        struct affs_sb_info *sbi = AFFS_SB(sb);
  49        pr_debug("AFFS: put_super()\n");
  50
  51        cancel_delayed_work_sync(&sbi->sb_work);
  52        kfree(sbi->s_prefix);
  53        affs_free_bitmap(sb);
  54        affs_brelse(sbi->s_root_bh);
  55        kfree(sbi);
  56        sb->s_fs_info = NULL;
  57}
  58
  59static int
  60affs_sync_fs(struct super_block *sb, int wait)
  61{
  62        affs_commit_super(sb, wait);
  63        return 0;
  64}
  65
  66static void flush_superblock(struct work_struct *work)
  67{
  68        struct affs_sb_info *sbi;
  69        struct super_block *sb;
  70
  71        sbi = container_of(work, struct affs_sb_info, sb_work.work);
  72        sb = sbi->sb;
  73
  74        spin_lock(&sbi->work_lock);
  75        sbi->work_queued = 0;
  76        spin_unlock(&sbi->work_lock);
  77
  78        affs_commit_super(sb, 1);
  79}
  80
  81void affs_mark_sb_dirty(struct super_block *sb)
  82{
  83        struct affs_sb_info *sbi = AFFS_SB(sb);
  84        unsigned long delay;
  85
  86        if (sb->s_flags & MS_RDONLY)
  87               return;
  88
  89        spin_lock(&sbi->work_lock);
  90        if (!sbi->work_queued) {
  91               delay = msecs_to_jiffies(dirty_writeback_interval * 10);
  92               queue_delayed_work(system_long_wq, &sbi->sb_work, delay);
  93               sbi->work_queued = 1;
  94        }
  95        spin_unlock(&sbi->work_lock);
  96}
  97
  98static struct kmem_cache * affs_inode_cachep;
  99
 100static struct inode *affs_alloc_inode(struct super_block *sb)
 101{
 102        struct affs_inode_info *i;
 103
 104        i = kmem_cache_alloc(affs_inode_cachep, GFP_KERNEL);
 105        if (!i)
 106                return NULL;
 107
 108        i->vfs_inode.i_version = 1;
 109        i->i_lc = NULL;
 110        i->i_ext_bh = NULL;
 111        i->i_pa_cnt = 0;
 112
 113        return &i->vfs_inode;
 114}
 115
 116static void affs_i_callback(struct rcu_head *head)
 117{
 118        struct inode *inode = container_of(head, struct inode, i_rcu);
 119        kmem_cache_free(affs_inode_cachep, AFFS_I(inode));
 120}
 121
 122static void affs_destroy_inode(struct inode *inode)
 123{
 124        call_rcu(&inode->i_rcu, affs_i_callback);
 125}
 126
 127static void init_once(void *foo)
 128{
 129        struct affs_inode_info *ei = (struct affs_inode_info *) foo;
 130
 131        sema_init(&ei->i_link_lock, 1);
 132        sema_init(&ei->i_ext_lock, 1);
 133        inode_init_once(&ei->vfs_inode);
 134}
 135
 136static int init_inodecache(void)
 137{
 138        affs_inode_cachep = kmem_cache_create("affs_inode_cache",
 139                                             sizeof(struct affs_inode_info),
 140                                             0, (SLAB_RECLAIM_ACCOUNT|
 141                                                SLAB_MEM_SPREAD),
 142                                             init_once);
 143        if (affs_inode_cachep == NULL)
 144                return -ENOMEM;
 145        return 0;
 146}
 147
 148static void destroy_inodecache(void)
 149{
 150        /*
 151         * Make sure all delayed rcu free inodes are flushed before we
 152         * destroy cache.
 153         */
 154        rcu_barrier();
 155        kmem_cache_destroy(affs_inode_cachep);
 156}
 157
 158static const struct super_operations affs_sops = {
 159        .alloc_inode    = affs_alloc_inode,
 160        .destroy_inode  = affs_destroy_inode,
 161        .write_inode    = affs_write_inode,
 162        .evict_inode    = affs_evict_inode,
 163        .put_super      = affs_put_super,
 164        .sync_fs        = affs_sync_fs,
 165        .statfs         = affs_statfs,
 166        .remount_fs     = affs_remount,
 167        .show_options   = generic_show_options,
 168};
 169
 170enum {
 171        Opt_bs, Opt_mode, Opt_mufs, Opt_prefix, Opt_protect,
 172        Opt_reserved, Opt_root, Opt_setgid, Opt_setuid,
 173        Opt_verbose, Opt_volume, Opt_ignore, Opt_err,
 174};
 175
 176static const match_table_t tokens = {
 177        {Opt_bs, "bs=%u"},
 178        {Opt_mode, "mode=%o"},
 179        {Opt_mufs, "mufs"},
 180        {Opt_prefix, "prefix=%s"},
 181        {Opt_protect, "protect"},
 182        {Opt_reserved, "reserved=%u"},
 183        {Opt_root, "root=%u"},
 184        {Opt_setgid, "setgid=%u"},
 185        {Opt_setuid, "setuid=%u"},
 186        {Opt_verbose, "verbose"},
 187        {Opt_volume, "volume=%s"},
 188        {Opt_ignore, "grpquota"},
 189        {Opt_ignore, "noquota"},
 190        {Opt_ignore, "quota"},
 191        {Opt_ignore, "usrquota"},
 192        {Opt_err, NULL},
 193};
 194
 195static int
 196parse_options(char *options, kuid_t *uid, kgid_t *gid, int *mode, int *reserved, s32 *root,
 197                int *blocksize, char **prefix, char *volume, unsigned long *mount_opts)
 198{
 199        char *p;
 200        substring_t args[MAX_OPT_ARGS];
 201
 202        /* Fill in defaults */
 203
 204        *uid        = current_uid();
 205        *gid        = current_gid();
 206        *reserved   = 2;
 207        *root       = -1;
 208        *blocksize  = -1;
 209        volume[0]   = ':';
 210        volume[1]   = 0;
 211        *mount_opts = 0;
 212        if (!options)
 213                return 1;
 214
 215        while ((p = strsep(&options, ",")) != NULL) {
 216                int token, n, option;
 217                if (!*p)
 218                        continue;
 219
 220                token = match_token(p, tokens, args);
 221                switch (token) {
 222                case Opt_bs:
 223                        if (match_int(&args[0], &n))
 224                                return 0;
 225                        if (n != 512 && n != 1024 && n != 2048
 226                            && n != 4096) {
 227                                printk ("AFFS: Invalid blocksize (512, 1024, 2048, 4096 allowed)\n");
 228                                return 0;
 229                        }
 230                        *blocksize = n;
 231                        break;
 232                case Opt_mode:
 233                        if (match_octal(&args[0], &option))
 234                                return 0;
 235                        *mode = option & 0777;
 236                        *mount_opts |= SF_SETMODE;
 237                        break;
 238                case Opt_mufs:
 239                        *mount_opts |= SF_MUFS;
 240                        break;
 241                case Opt_prefix:
 242                        *prefix = match_strdup(&args[0]);
 243                        if (!*prefix)
 244                                return 0;
 245                        *mount_opts |= SF_PREFIX;
 246                        break;
 247                case Opt_protect:
 248                        *mount_opts |= SF_IMMUTABLE;
 249                        break;
 250                case Opt_reserved:
 251                        if (match_int(&args[0], reserved))
 252                                return 0;
 253                        break;
 254                case Opt_root:
 255                        if (match_int(&args[0], root))
 256                                return 0;
 257                        break;
 258                case Opt_setgid:
 259                        if (match_int(&args[0], &option))
 260                                return 0;
 261                        *gid = make_kgid(current_user_ns(), option);
 262                        if (!gid_valid(*gid))
 263                                return 0;
 264                        *mount_opts |= SF_SETGID;
 265                        break;
 266                case Opt_setuid:
 267                        if (match_int(&args[0], &option))
 268                                return 0;
 269                        *uid = make_kuid(current_user_ns(), option);
 270                        if (!uid_valid(*uid))
 271                                return 0;
 272                        *mount_opts |= SF_SETUID;
 273                        break;
 274                case Opt_verbose:
 275                        *mount_opts |= SF_VERBOSE;
 276                        break;
 277                case Opt_volume: {
 278                        char *vol = match_strdup(&args[0]);
 279                        if (!vol)
 280                                return 0;
 281                        strlcpy(volume, vol, 32);
 282                        kfree(vol);
 283                        break;
 284                }
 285                case Opt_ignore:
 286                        /* Silently ignore the quota options */
 287                        break;
 288                default:
 289                        printk("AFFS: Unrecognized mount option \"%s\" "
 290                                        "or missing value\n", p);
 291                        return 0;
 292                }
 293        }
 294        return 1;
 295}
 296
 297/* This function definitely needs to be split up. Some fine day I'll
 298 * hopefully have the guts to do so. Until then: sorry for the mess.
 299 */
 300
 301static int affs_fill_super(struct super_block *sb, void *data, int silent)
 302{
 303        struct affs_sb_info     *sbi;
 304        struct buffer_head      *root_bh = NULL;
 305        struct buffer_head      *boot_bh;
 306        struct inode            *root_inode = NULL;
 307        s32                      root_block;
 308        int                      size, blocksize;
 309        u32                      chksum;
 310        int                      num_bm;
 311        int                      i, j;
 312        s32                      key;
 313        kuid_t                   uid;
 314        kgid_t                   gid;
 315        int                      reserved;
 316        unsigned long            mount_flags;
 317        int                      tmp_flags;     /* fix remount prototype... */
 318        u8                       sig[4];
 319        int                      ret = -EINVAL;
 320
 321        save_mount_options(sb, data);
 322
 323        pr_debug("AFFS: read_super(%s)\n",data ? (const char *)data : "no options");
 324
 325        sb->s_magic             = AFFS_SUPER_MAGIC;
 326        sb->s_op                = &affs_sops;
 327        sb->s_flags |= MS_NODIRATIME;
 328
 329        sbi = kzalloc(sizeof(struct affs_sb_info), GFP_KERNEL);
 330        if (!sbi)
 331                return -ENOMEM;
 332
 333        sb->s_fs_info = sbi;
 334        sbi->sb = sb;
 335        mutex_init(&sbi->s_bmlock);
 336        spin_lock_init(&sbi->symlink_lock);
 337        spin_lock_init(&sbi->work_lock);
 338        INIT_DELAYED_WORK(&sbi->sb_work, flush_superblock);
 339
 340        if (!parse_options(data,&uid,&gid,&i,&reserved,&root_block,
 341                                &blocksize,&sbi->s_prefix,
 342                                sbi->s_volume, &mount_flags)) {
 343                printk(KERN_ERR "AFFS: Error parsing options\n");
 344                kfree(sbi->s_prefix);
 345                kfree(sbi);
 346                return -EINVAL;
 347        }
 348        /* N.B. after this point s_prefix must be released */
 349
 350        sbi->s_flags   = mount_flags;
 351        sbi->s_mode    = i;
 352        sbi->s_uid     = uid;
 353        sbi->s_gid     = gid;
 354        sbi->s_reserved= reserved;
 355
 356        /* Get the size of the device in 512-byte blocks.
 357         * If we later see that the partition uses bigger
 358         * blocks, we will have to change it.
 359         */
 360
 361        size = sb->s_bdev->bd_inode->i_size >> 9;
 362        pr_debug("AFFS: initial blocksize=%d, #blocks=%d\n", 512, size);
 363
 364        affs_set_blocksize(sb, PAGE_SIZE);
 365        /* Try to find root block. Its location depends on the block size. */
 366
 367        i = 512;
 368        j = 4096;
 369        if (blocksize > 0) {
 370                i = j = blocksize;
 371                size = size / (blocksize / 512);
 372        }
 373        for (blocksize = i, key = 0; blocksize <= j; blocksize <<= 1, size >>= 1) {
 374                sbi->s_root_block = root_block;
 375                if (root_block < 0)
 376                        sbi->s_root_block = (reserved + size - 1) / 2;
 377                pr_debug("AFFS: setting blocksize to %d\n", blocksize);
 378                affs_set_blocksize(sb, blocksize);
 379                sbi->s_partition_size = size;
 380
 381                /* The root block location that was calculated above is not
 382                 * correct if the partition size is an odd number of 512-
 383                 * byte blocks, which will be rounded down to a number of
 384                 * 1024-byte blocks, and if there were an even number of
 385                 * reserved blocks. Ideally, all partition checkers should
 386                 * report the real number of blocks of the real blocksize,
 387                 * but since this just cannot be done, we have to try to
 388                 * find the root block anyways. In the above case, it is one
 389                 * block behind the calculated one. So we check this one, too.
 390                 */
 391                for (num_bm = 0; num_bm < 2; num_bm++) {
 392                        pr_debug("AFFS: Dev %s, trying root=%u, bs=%d, "
 393                                "size=%d, reserved=%d\n",
 394                                sb->s_id,
 395                                sbi->s_root_block + num_bm,
 396                                blocksize, size, reserved);
 397                        root_bh = affs_bread(sb, sbi->s_root_block + num_bm);
 398                        if (!root_bh)
 399                                continue;
 400                        if (!affs_checksum_block(sb, root_bh) &&
 401                            be32_to_cpu(AFFS_ROOT_HEAD(root_bh)->ptype) == T_SHORT &&
 402                            be32_to_cpu(AFFS_ROOT_TAIL(sb, root_bh)->stype) == ST_ROOT) {
 403                                sbi->s_hashsize    = blocksize / 4 - 56;
 404                                sbi->s_root_block += num_bm;
 405                                key                        = 1;
 406                                goto got_root;
 407                        }
 408                        affs_brelse(root_bh);
 409                        root_bh = NULL;
 410                }
 411        }
 412        if (!silent)
 413                printk(KERN_ERR "AFFS: No valid root block on device %s\n",
 414                        sb->s_id);
 415        goto out_error;
 416
 417        /* N.B. after this point bh must be released */
 418got_root:
 419        root_block = sbi->s_root_block;
 420
 421        /* Find out which kind of FS we have */
 422        boot_bh = sb_bread(sb, 0);
 423        if (!boot_bh) {
 424                printk(KERN_ERR "AFFS: Cannot read boot block\n");
 425                goto out_error;
 426        }
 427        memcpy(sig, boot_bh->b_data, 4);
 428        brelse(boot_bh);
 429        chksum = be32_to_cpu(*(__be32 *)sig);
 430
 431        /* Dircache filesystems are compatible with non-dircache ones
 432         * when reading. As long as they aren't supported, writing is
 433         * not recommended.
 434         */
 435        if ((chksum == FS_DCFFS || chksum == MUFS_DCFFS || chksum == FS_DCOFS
 436             || chksum == MUFS_DCOFS) && !(sb->s_flags & MS_RDONLY)) {
 437                printk(KERN_NOTICE "AFFS: Dircache FS - mounting %s read only\n",
 438                        sb->s_id);
 439                sb->s_flags |= MS_RDONLY;
 440        }
 441        switch (chksum) {
 442                case MUFS_FS:
 443                case MUFS_INTLFFS:
 444                case MUFS_DCFFS:
 445                        sbi->s_flags |= SF_MUFS;
 446                        /* fall thru */
 447                case FS_INTLFFS:
 448                case FS_DCFFS:
 449                        sbi->s_flags |= SF_INTL;
 450                        break;
 451                case MUFS_FFS:
 452                        sbi->s_flags |= SF_MUFS;
 453                        break;
 454                case FS_FFS:
 455                        break;
 456                case MUFS_OFS:
 457                        sbi->s_flags |= SF_MUFS;
 458                        /* fall thru */
 459                case FS_OFS:
 460                        sbi->s_flags |= SF_OFS;
 461                        sb->s_flags |= MS_NOEXEC;
 462                        break;
 463                case MUFS_DCOFS:
 464                case MUFS_INTLOFS:
 465                        sbi->s_flags |= SF_MUFS;
 466                case FS_DCOFS:
 467                case FS_INTLOFS:
 468                        sbi->s_flags |= SF_INTL | SF_OFS;
 469                        sb->s_flags |= MS_NOEXEC;
 470                        break;
 471                default:
 472                        printk(KERN_ERR "AFFS: Unknown filesystem on device %s: %08X\n",
 473                                sb->s_id, chksum);
 474                        goto out_error;
 475        }
 476
 477        if (mount_flags & SF_VERBOSE) {
 478                u8 len = AFFS_ROOT_TAIL(sb, root_bh)->disk_name[0];
 479                printk(KERN_NOTICE "AFFS: Mounting volume \"%.*s\": Type=%.3s\\%c, Blocksize=%d\n",
 480                        len > 31 ? 31 : len,
 481                        AFFS_ROOT_TAIL(sb, root_bh)->disk_name + 1,
 482                        sig, sig[3] + '0', blocksize);
 483        }
 484
 485        sb->s_flags |= MS_NODEV | MS_NOSUID;
 486
 487        sbi->s_data_blksize = sb->s_blocksize;
 488        if (sbi->s_flags & SF_OFS)
 489                sbi->s_data_blksize -= 24;
 490
 491        /* Keep super block in cache */
 492        sbi->s_root_bh = root_bh;
 493        /* N.B. after this point s_root_bh must be released */
 494
 495        tmp_flags = sb->s_flags;
 496        if (affs_init_bitmap(sb, &tmp_flags))
 497                goto out_error;
 498        sb->s_flags = tmp_flags;
 499
 500        /* set up enough so that it can read an inode */
 501
 502        root_inode = affs_iget(sb, root_block);
 503        if (IS_ERR(root_inode)) {
 504                ret = PTR_ERR(root_inode);
 505                goto out_error;
 506        }
 507
 508        if (AFFS_SB(sb)->s_flags & SF_INTL)
 509                sb->s_d_op = &affs_intl_dentry_operations;
 510        else
 511                sb->s_d_op = &affs_dentry_operations;
 512
 513        sb->s_root = d_make_root(root_inode);
 514        if (!sb->s_root) {
 515                printk(KERN_ERR "AFFS: Get root inode failed\n");
 516                goto out_error;
 517        }
 518
 519        pr_debug("AFFS: s_flags=%lX\n",sb->s_flags);
 520        return 0;
 521
 522        /*
 523         * Begin the cascaded cleanup ...
 524         */
 525out_error:
 526        kfree(sbi->s_bitmap);
 527        affs_brelse(root_bh);
 528        kfree(sbi->s_prefix);
 529        kfree(sbi);
 530        sb->s_fs_info = NULL;
 531        return ret;
 532}
 533
 534static int
 535affs_remount(struct super_block *sb, int *flags, char *data)
 536{
 537        struct affs_sb_info     *sbi = AFFS_SB(sb);
 538        int                      blocksize;
 539        kuid_t                   uid;
 540        kgid_t                   gid;
 541        int                      mode;
 542        int                      reserved;
 543        int                      root_block;
 544        unsigned long            mount_flags;
 545        int                      res = 0;
 546        char                    *new_opts = kstrdup(data, GFP_KERNEL);
 547        char                     volume[32];
 548        char                    *prefix = NULL;
 549
 550        pr_debug("AFFS: remount(flags=0x%x,opts=\"%s\")\n",*flags,data);
 551
 552        *flags |= MS_NODIRATIME;
 553
 554        memcpy(volume, sbi->s_volume, 32);
 555        if (!parse_options(data, &uid, &gid, &mode, &reserved, &root_block,
 556                           &blocksize, &prefix, volume,
 557                           &mount_flags)) {
 558                kfree(prefix);
 559                kfree(new_opts);
 560                return -EINVAL;
 561        }
 562
 563        flush_delayed_work(&sbi->sb_work);
 564        replace_mount_options(sb, new_opts);
 565
 566        sbi->s_flags = mount_flags;
 567        sbi->s_mode  = mode;
 568        sbi->s_uid   = uid;
 569        sbi->s_gid   = gid;
 570        /* protect against readers */
 571        spin_lock(&sbi->symlink_lock);
 572        if (prefix) {
 573                kfree(sbi->s_prefix);
 574                sbi->s_prefix = prefix;
 575        }
 576        memcpy(sbi->s_volume, volume, 32);
 577        spin_unlock(&sbi->symlink_lock);
 578
 579        if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 580                return 0;
 581
 582        if (*flags & MS_RDONLY)
 583                affs_free_bitmap(sb);
 584        else
 585                res = affs_init_bitmap(sb, flags);
 586
 587        return res;
 588}
 589
 590static int
 591affs_statfs(struct dentry *dentry, struct kstatfs *buf)
 592{
 593        struct super_block *sb = dentry->d_sb;
 594        int              free;
 595        u64              id = huge_encode_dev(sb->s_bdev->bd_dev);
 596
 597        pr_debug("AFFS: statfs() partsize=%d, reserved=%d\n",AFFS_SB(sb)->s_partition_size,
 598             AFFS_SB(sb)->s_reserved);
 599
 600        free          = affs_count_free_blocks(sb);
 601        buf->f_type    = AFFS_SUPER_MAGIC;
 602        buf->f_bsize   = sb->s_blocksize;
 603        buf->f_blocks  = AFFS_SB(sb)->s_partition_size - AFFS_SB(sb)->s_reserved;
 604        buf->f_bfree   = free;
 605        buf->f_bavail  = free;
 606        buf->f_fsid.val[0] = (u32)id;
 607        buf->f_fsid.val[1] = (u32)(id >> 32);
 608        buf->f_namelen = 30;
 609        return 0;
 610}
 611
 612static struct dentry *affs_mount(struct file_system_type *fs_type,
 613        int flags, const char *dev_name, void *data)
 614{
 615        return mount_bdev(fs_type, flags, dev_name, data, affs_fill_super);
 616}
 617
 618static struct file_system_type affs_fs_type = {
 619        .owner          = THIS_MODULE,
 620        .name           = "affs",
 621        .mount          = affs_mount,
 622        .kill_sb        = kill_block_super,
 623        .fs_flags       = FS_REQUIRES_DEV,
 624};
 625MODULE_ALIAS_FS("affs");
 626
 627static int __init init_affs_fs(void)
 628{
 629        int err = init_inodecache();
 630        if (err)
 631                goto out1;
 632        err = register_filesystem(&affs_fs_type);
 633        if (err)
 634                goto out;
 635        return 0;
 636out:
 637        destroy_inodecache();
 638out1:
 639        return err;
 640}
 641
 642static void __exit exit_affs_fs(void)
 643{
 644        unregister_filesystem(&affs_fs_type);
 645        destroy_inodecache();
 646}
 647
 648MODULE_DESCRIPTION("Amiga filesystem support for Linux");
 649MODULE_LICENSE("GPL");
 650
 651module_init(init_affs_fs)
 652module_exit(exit_affs_fs)
 653
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