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