fs/affs/super.c

   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 "affs.h"
  21
  22 extern struct timezone sys_tz;
  23
  24 static int affs_statfs(struct dentry *dentry, struct kstatfs *buf);
  25 static int affs_remount (struct super_block *sb, int *flags, char *data);
  26
  27 static void
  28 affs_commit_super(struct super_block *sb, int wait, int clean)
  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         tail->bm_flag = cpu_to_be32(clean);
  35         secs_to_datestamp(get_seconds(), &tail->disk_change);
  36         affs_fix_checksum(sb, bh);
  37         mark_buffer_dirty(bh);
  38         if (wait)
  39                 sync_dirty_buffer(bh);
  40 }
  41
  42 static void
  43 affs_put_super(struct super_block *sb)
  44 {
  45         struct affs_sb_info *sbi = AFFS_SB(sb);
  46         pr_debug("AFFS: put_super()\n");
  47
  48         if (!(sb->s_flags & MS_RDONLY) && sb->s_dirt)
  49                 affs_commit_super(sb, 1, 1);
  50
  51         kfree(sbi->s_prefix);
  52         affs_free_bitmap(sb);
  53         affs_brelse(sbi->s_root_bh);
  54         kfree(sbi);
  55         sb->s_fs_info = NULL;
  56 }
  57
  58 static void
  59 affs_write_super(struct super_block *sb)
  60 {
  61         lock_super(sb);
  62         if (!(sb->s_flags & MS_RDONLY))
  63                 affs_commit_super(sb, 1, 2);
  64         sb->s_dirt = 0;
  65         unlock_super(sb);
  66
  67         pr_debug("AFFS: write_super() at %lu, clean=2\n", get_seconds());
  68 }
  69
  70 static int
  71 affs_sync_fs(struct super_block *sb, int wait)
  72 {
  73         lock_super(sb);
  74         affs_commit_super(sb, wait, 2);
  75         sb->s_dirt = 0;
  76         unlock_super(sb);
  77         return 0;
  78 }
  79
  80 static struct kmem_cache * affs_inode_cachep;
  81
  82 static struct inode *affs_alloc_inode(struct super_block *sb)
  83 {
  84         struct affs_inode_info *i;
  85
  86         i = kmem_cache_alloc(affs_inode_cachep, GFP_KERNEL);
  87         if (!i)
  88                 return NULL;
  89
  90         i->vfs_inode.i_version = 1;
  91         i->i_lc = NULL;
  92         i->i_ext_bh = NULL;
  93         i->i_pa_cnt = 0;
  94
  95         return &i->vfs_inode;
  96 }
  97
  98 static void affs_i_callback(struct rcu_head *head)
  99 {
 100         struct inode *inode = container_of(head, struct inode, i_rcu);
 101         INIT_LIST_HEAD(&inode->i_dentry);
 102         kmem_cache_free(affs_inode_cachep, AFFS_I(inode));
 103 }
 104
 105 static void affs_destroy_inode(struct inode *inode)
 106 {
 107         call_rcu(&inode->i_rcu, affs_i_callback);
 108 }
 109
 110 static void init_once(void *foo)
 111 {
 112         struct affs_inode_info *ei = (struct affs_inode_info *) foo;
 113
 114         sema_init(&ei->i_link_lock, 1);
 115         sema_init(&ei->i_ext_lock, 1);
 116         inode_init_once(&ei->vfs_inode);
 117 }
 118
 119 static int init_inodecache(void)
 120 {
 121         affs_inode_cachep = kmem_cache_create("affs_inode_cache",
 122                                              sizeof(struct affs_inode_info),
 123                                              0, (SLAB_RECLAIM_ACCOUNT|
 124                                                 SLAB_MEM_SPREAD),
 125                                              init_once);
 126         if (affs_inode_cachep == NULL)
 127                 return -ENOMEM;
 128         return 0;
 129 }
 130
 131 static void destroy_inodecache(void)
 132 {
 133         kmem_cache_destroy(affs_inode_cachep);
 134 }
 135
 136 static const struct super_operations affs_sops = {
 137         .alloc_inode    = affs_alloc_inode,
 138         .destroy_inode  = affs_destroy_inode,
 139         .write_inode    = affs_write_inode,
 140         .evict_inode    = affs_evict_inode,
 141         .put_super      = affs_put_super,
 142         .write_super    = affs_write_super,
 143         .sync_fs        = affs_sync_fs,
 144         .statfs         = affs_statfs,
 145         .remount_fs     = affs_remount,
 146         .show_options   = generic_show_options,
 147 };
 148
 149 enum {
 150         Opt_bs, Opt_mode, Opt_mufs, Opt_prefix, Opt_protect,
 151         Opt_reserved, Opt_root, Opt_setgid, Opt_setuid,
 152         Opt_verbose, Opt_volume, Opt_ignore, Opt_err,
 153 };
 154
 155 static const match_table_t tokens = {
 156         {Opt_bs, "bs=%u"},
 157         {Opt_mode, "mode=%o"},
 158         {Opt_mufs, "mufs"},
 159         {Opt_prefix, "prefix=%s"},
 160         {Opt_protect, "protect"},
 161         {Opt_reserved, "reserved=%u"},
 162         {Opt_root, "root=%u"},
 163         {Opt_setgid, "setgid=%u"},
 164         {Opt_setuid, "setuid=%u"},
 165         {Opt_verbose, "verbose"},
 166         {Opt_volume, "volume=%s"},
 167         {Opt_ignore, "grpquota"},
 168         {Opt_ignore, "noquota"},
 169         {Opt_ignore, "quota"},
 170         {Opt_ignore, "usrquota"},
 171         {Opt_err, NULL},
 172 };
 173
 174 static int
 175 parse_options(char *options, uid_t *uid, gid_t *gid, int *mode, int *reserved, s32 *root,
 176                 int *blocksize, char **prefix, char *volume, unsigned long *mount_opts)
 177 {
 178         char *p;
 179         substring_t args[MAX_OPT_ARGS];
 180
 181         /* Fill in defaults */
 182
 183         *uid        = current_uid();
 184         *gid        = current_gid();
 185         *reserved   = 2;
 186         *root       = -1;
 187         *blocksize  = -1;
 188         volume[0]   = ':';
 189         volume[1]   = 0;
 190         *mount_opts = 0;
 191         if (!options)
 192                 return 1;
 193
 194         while ((p = strsep(&options, ",")) != NULL) {
 195                 int token, n, option;
 196                 if (!*p)
 197                         continue;
 198
 199                 token = match_token(p, tokens, args);
 200                 switch (token) {
 201                 case Opt_bs:
 202                         if (match_int(&args[0], &n))
 203                                 return 0;
 204                         if (n != 512 && n != 1024 && n != 2048
 205                             && n != 4096) {
 206                                 printk ("AFFS: Invalid blocksize (512, 1024, 2048, 4096 allowed)\n");
 207                                 return 0;
 208                         }
 209                         *blocksize = n;
 210                         break;
 211                 case Opt_mode:
 212                         if (match_octal(&args[0], &option))
 213                                 return 0;
 214                         *mode = option & 0777;
 215                         *mount_opts |= SF_SETMODE;
 216                         break;
 217                 case Opt_mufs:
 218                         *mount_opts |= SF_MUFS;
 219                         break;
 220                 case Opt_prefix:
 221                         *prefix = match_strdup(&args[0]);
 222                         if (!*prefix)
 223                                 return 0;
 224                         *mount_opts |= SF_PREFIX;
 225                         break;
 226                 case Opt_protect:
 227                         *mount_opts |= SF_IMMUTABLE;
 228                         break;
 229                 case Opt_reserved:
 230                         if (match_int(&args[0], reserved))
 231                                 return 0;
 232                         break;
 233                 case Opt_root:
 234                         if (match_int(&args[0], root))
 235                                 return 0;
 236                         break;
 237                 case Opt_setgid:
 238                         if (match_int(&args[0], &option))
 239                                 return 0;
 240                         *gid = option;
 241                         *mount_opts |= SF_SETGID;
 242                         break;
 243                 case Opt_setuid:
 244                         if (match_int(&args[0], &option))
 245                                 return 0;
 246                         *uid = option;
 247                         *mount_opts |= SF_SETUID;
 248                         break;
 249                 case Opt_verbose:
 250                         *mount_opts |= SF_VERBOSE;
 251                         break;
 252                 case Opt_volume: {
 253                         char *vol = match_strdup(&args[0]);
 254                         if (!vol)
 255                                 return 0;
 256                         strlcpy(volume, vol, 32);
 257                         kfree(vol);
 258                         break;
 259                 }
 260                 case Opt_ignore:
 261                         /* Silently ignore the quota options */
 262                         break;
 263                 default:
 264                         printk("AFFS: Unrecognized mount option \"%s\" "
 265                                         "or missing value\n", p);
 266                         return 0;
 267                 }
 268         }
 269         return 1;
 270 }
 271
 272 /* This function definitely needs to be split up. Some fine day I'll
 273  * hopefully have the guts to do so. Until then: sorry for the mess.
 274  */
 275
 276 static int affs_fill_super(struct super_block *sb, void *data, int silent)
 277 {
 278         struct affs_sb_info     *sbi;
 279         struct buffer_head      *root_bh = NULL;
 280         struct buffer_head      *boot_bh;
 281         struct inode            *root_inode = NULL;
 282         s32                      root_block;
 283         int                      size, blocksize;
 284         u32                      chksum;
 285         int                      num_bm;
 286         int                      i, j;
 287         s32                      key;
 288         uid_t                    uid;
 289         gid_t                    gid;
 290         int                      reserved;
 291         unsigned long            mount_flags;
 292         int                      tmp_flags;     /* fix remount prototype... */
 293         u8                       sig[4];
 294         int                      ret = -EINVAL;
 295
 296         save_mount_options(sb, data);
 297
 298         pr_debug("AFFS: read_super(%s)\n",data ? (const char *)data : "no options");
 299
 300         sb->s_magic             = AFFS_SUPER_MAGIC;
 301         sb->s_op                = &affs_sops;
 302         sb->s_flags |= MS_NODIRATIME;
 303
 304         sbi = kzalloc(sizeof(struct affs_sb_info), GFP_KERNEL);
 305         if (!sbi)
 306                 return -ENOMEM;
 307
 308         sb->s_fs_info = sbi;
 309         mutex_init(&sbi->s_bmlock);
 310         spin_lock_init(&sbi->symlink_lock);
 311
 312         if (!parse_options(data,&uid,&gid,&i,&reserved,&root_block,
 313                                 &blocksize,&sbi->s_prefix,
 314                                 sbi->s_volume, &mount_flags)) {
 315                 printk(KERN_ERR "AFFS: Error parsing options\n");
 316                 kfree(sbi->s_prefix);
 317                 kfree(sbi);
 318                 return -EINVAL;
 319         }
 320         /* N.B. after this point s_prefix must be released */
 321
 322         sbi->s_flags   = mount_flags;
 323         sbi->s_mode    = i;
 324         sbi->s_uid     = uid;
 325         sbi->s_gid     = gid;
 326         sbi->s_reserved= reserved;
 327
 328         /* Get the size of the device in 512-byte blocks.
 329          * If we later see that the partition uses bigger
 330          * blocks, we will have to change it.
 331          */
 332
 333         size = sb->s_bdev->bd_inode->i_size >> 9;
 334         pr_debug("AFFS: initial blocksize=%d, #blocks=%d\n", 512, size);
 335
 336         affs_set_blocksize(sb, PAGE_SIZE);
 337         /* Try to find root block. Its location depends on the block size. */
 338
 339         i = 512;
 340         j = 4096;
 341         if (blocksize > 0) {
 342                 i = j = blocksize;
 343                 size = size / (blocksize / 512);
 344         }
 345         for (blocksize = i, key = 0; blocksize <= j; blocksize <<= 1, size >>= 1) {
 346                 sbi->s_root_block = root_block;
 347                 if (root_block < 0)
 348                         sbi->s_root_block = (reserved + size - 1) / 2;
 349                 pr_debug("AFFS: setting blocksize to %d\n", blocksize);
 350                 affs_set_blocksize(sb, blocksize);
 351                 sbi->s_partition_size = size;
 352
 353                 /* The root block location that was calculated above is not
 354                  * correct if the partition size is an odd number of 512-
 355                  * byte blocks, which will be rounded down to a number of
 356                  * 1024-byte blocks, and if there were an even number of
 357                  * reserved blocks. Ideally, all partition checkers should
 358                  * report the real number of blocks of the real blocksize,
 359                  * but since this just cannot be done, we have to try to
 360                  * find the root block anyways. In the above case, it is one
 361                  * block behind the calculated one. So we check this one, too.
 362                  */
 363                 for (num_bm = 0; num_bm < 2; num_bm++) {
 364                         pr_debug("AFFS: Dev %s, trying root=%u, bs=%d, "
 365                                 "size=%d, reserved=%d\n",
 366                                 sb->s_id,
 367                                 sbi->s_root_block + num_bm,
 368                                 blocksize, size, reserved);
 369                         root_bh = affs_bread(sb, sbi->s_root_block + num_bm);
 370                         if (!root_bh)
 371                                 continue;
 372                         if (!affs_checksum_block(sb, root_bh) &&
 373                             be32_to_cpu(AFFS_ROOT_HEAD(root_bh)->ptype) == T_SHORT &&
 374                             be32_to_cpu(AFFS_ROOT_TAIL(sb, root_bh)->stype) == ST_ROOT) {
 375                                 sbi->s_hashsize    = blocksize / 4 - 56;
 376                                 sbi->s_root_block += num_bm;
 377                                 key                        = 1;
 378                                 goto got_root;
 379                         }
 380                         affs_brelse(root_bh);
 381                         root_bh = NULL;
 382                 }
 383         }
 384         if (!silent)
 385                 printk(KERN_ERR "AFFS: No valid root block on device %s\n",
 386                         sb->s_id);
 387         goto out_error;
 388
 389         /* N.B. after this point bh must be released */
 390 got_root:
 391         root_block = sbi->s_root_block;
 392
 393         /* Find out which kind of FS we have */
 394         boot_bh = sb_bread(sb, 0);
 395         if (!boot_bh) {
 396                 printk(KERN_ERR "AFFS: Cannot read boot block\n");
 397                 goto out_error;
 398         }
 399         memcpy(sig, boot_bh->b_data, 4);
 400         brelse(boot_bh);
 401         chksum = be32_to_cpu(*(__be32 *)sig);
 402
 403         /* Dircache filesystems are compatible with non-dircache ones
 404          * when reading. As long as they aren't supported, writing is
 405          * not recommended.
 406          */
 407         if ((chksum == FS_DCFFS || chksum == MUFS_DCFFS || chksum == FS_DCOFS
 408              || chksum == MUFS_DCOFS) && !(sb->s_flags & MS_RDONLY)) {
 409                 printk(KERN_NOTICE "AFFS: Dircache FS - mounting %s read only\n",
 410                         sb->s_id);
 411                 sb->s_flags |= MS_RDONLY;
 412         }
 413         switch (chksum) {
 414                 case MUFS_FS:
 415                 case MUFS_INTLFFS:
 416                 case MUFS_DCFFS:
 417                         sbi->s_flags |= SF_MUFS;
 418                         /* fall thru */
 419                 case FS_INTLFFS:
 420                 case FS_DCFFS:
 421                         sbi->s_flags |= SF_INTL;
 422                         break;
 423                 case MUFS_FFS:
 424                         sbi->s_flags |= SF_MUFS;
 425                         break;
 426                 case FS_FFS:
 427                         break;
 428                 case MUFS_OFS:
 429                         sbi->s_flags |= SF_MUFS;
 430                         /* fall thru */
 431                 case FS_OFS:
 432                         sbi->s_flags |= SF_OFS;
 433                         sb->s_flags |= MS_NOEXEC;
 434                         break;
 435                 case MUFS_DCOFS:
 436                 case MUFS_INTLOFS:
 437                         sbi->s_flags |= SF_MUFS;
 438                 case FS_DCOFS:
 439                 case FS_INTLOFS:
 440                         sbi->s_flags |= SF_INTL | SF_OFS;
 441                         sb->s_flags |= MS_NOEXEC;
 442                         break;
 443                 default:
 444                         printk(KERN_ERR "AFFS: Unknown filesystem on device %s: %08X\n",
 445                                 sb->s_id, chksum);
 446                         goto out_error;
 447         }
 448
 449         if (mount_flags & SF_VERBOSE) {
 450                 u8 len = AFFS_ROOT_TAIL(sb, root_bh)->disk_name[0];
 451                 printk(KERN_NOTICE "AFFS: Mounting volume \"%.*s\": Type=%.3s\\%c, Blocksize=%d\n",
 452                         len > 31 ? 31 : len,
 453                         AFFS_ROOT_TAIL(sb, root_bh)->disk_name + 1,
 454                         sig, sig[3] + '0', blocksize);
 455         }
 456
 457         sb->s_flags |= MS_NODEV | MS_NOSUID;
 458
 459         sbi->s_data_blksize = sb->s_blocksize;
 460         if (sbi->s_flags & SF_OFS)
 461                 sbi->s_data_blksize -= 24;
 462
 463         /* Keep super block in cache */
 464         sbi->s_root_bh = root_bh;
 465         /* N.B. after this point s_root_bh must be released */
 466
 467         tmp_flags = sb->s_flags;
 468         if (affs_init_bitmap(sb, &tmp_flags))
 469                 goto out_error;
 470         sb->s_flags = tmp_flags;
 471
 472         /* set up enough so that it can read an inode */
 473
 474         root_inode = affs_iget(sb, root_block);
 475         if (IS_ERR(root_inode)) {
 476                 ret = PTR_ERR(root_inode);
 477                 goto out_error_noinode;
 478         }
 479
 480         if (AFFS_SB(sb)->s_flags & SF_INTL)
 481                 sb->s_d_op = &affs_intl_dentry_operations;
 482         else
 483                 sb->s_d_op = &affs_dentry_operations;
 484
 485         sb->s_root = d_alloc_root(root_inode);
 486         if (!sb->s_root) {
 487                 printk(KERN_ERR "AFFS: Get root inode failed\n");
 488                 goto out_error;
 489         }
 490
 491         pr_debug("AFFS: s_flags=%lX\n",sb->s_flags);
 492         return 0;
 493
 494         /*
 495          * Begin the cascaded cleanup ...
 496          */
 497 out_error:
 498         if (root_inode)
 499                 iput(root_inode);
 500 out_error_noinode:
 501         kfree(sbi->s_bitmap);
 502         affs_brelse(root_bh);
 503         kfree(sbi->s_prefix);
 504         kfree(sbi);
 505         sb->s_fs_info = NULL;
 506         return ret;
 507 }
 508
 509 static int
 510 affs_remount(struct super_block *sb, int *flags, char *data)
 511 {
 512         struct affs_sb_info     *sbi = AFFS_SB(sb);
 513         int                      blocksize;
 514         uid_t                    uid;
 515         gid_t                    gid;
 516         int                      mode;
 517         int                      reserved;
 518         int                      root_block;
 519         unsigned long            mount_flags;
 520         int                      res = 0;
 521         char                    *new_opts = kstrdup(data, GFP_KERNEL);
 522         char                     volume[32];
 523         char                    *prefix = NULL;
 524
 525         pr_debug("AFFS: remount(flags=0x%x,opts=\"%s\")\n",*flags,data);
 526
 527         *flags |= MS_NODIRATIME;
 528
 529         memcpy(volume, sbi->s_volume, 32);
 530         if (!parse_options(data, &uid, &gid, &mode, &reserved, &root_block,
 531                            &blocksize, &prefix, volume,
 532                            &mount_flags)) {
 533                 kfree(prefix);
 534                 kfree(new_opts);
 535                 return -EINVAL;
 536         }
 537
 538         replace_mount_options(sb, new_opts);
 539
 540         sbi->s_flags = mount_flags;
 541         sbi->s_mode  = mode;
 542         sbi->s_uid   = uid;
 543         sbi->s_gid   = gid;
 544         /* protect against readers */
 545         spin_lock(&sbi->symlink_lock);
 546         if (prefix) {
 547                 kfree(sbi->s_prefix);
 548                 sbi->s_prefix = prefix;
 549         }
 550         memcpy(sbi->s_volume, volume, 32);
 551         spin_unlock(&sbi->symlink_lock);
 552
 553         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 554                 return 0;
 555
 556         if (*flags & MS_RDONLY) {
 557                 affs_write_super(sb);
 558                 affs_free_bitmap(sb);
 559         } else
 560                 res = affs_init_bitmap(sb, flags);
 561
 562         return res;
 563 }
 564
 565 static int
 566 affs_statfs(struct dentry *dentry, struct kstatfs *buf)
 567 {
 568         struct super_block *sb = dentry->d_sb;
 569         int              free;
 570         u64              id = huge_encode_dev(sb->s_bdev->bd_dev);
 571
 572         pr_debug("AFFS: statfs() partsize=%d, reserved=%d\n",AFFS_SB(sb)->s_partition_size,
 573              AFFS_SB(sb)->s_reserved);
 574
 575         free          = affs_count_free_blocks(sb);
 576         buf->f_type    = AFFS_SUPER_MAGIC;
 577         buf->f_bsize   = sb->s_blocksize;
 578         buf->f_blocks  = AFFS_SB(sb)->s_partition_size - AFFS_SB(sb)->s_reserved;
 579         buf->f_bfree   = free;
 580         buf->f_bavail  = free;
 581         buf->f_fsid.val[0] = (u32)id;
 582         buf->f_fsid.val[1] = (u32)(id >> 32);
 583         buf->f_namelen = 30;
 584         return 0;
 585 }
 586
 587 static struct dentry *affs_mount(struct file_system_type *fs_type,
 588         int flags, const char *dev_name, void *data)
 589 {
 590         return mount_bdev(fs_type, flags, dev_name, data, affs_fill_super);
 591 }
 592
 593 static struct file_system_type affs_fs_type = {
 594         .owner          = THIS_MODULE,
 595         .name           = "affs",
 596         .mount          = affs_mount,
 597         .kill_sb        = kill_block_super,
 598         .fs_flags       = FS_REQUIRES_DEV,
 599 };
 600
 601 static int __init init_affs_fs(void)
 602 {
 603         int err = init_inodecache();
 604         if (err)
 605                 goto out1;
 606         err = register_filesystem(&affs_fs_type);
 607         if (err)
 608                 goto out;
 609         return 0;
 610 out:
 611         destroy_inodecache();
 612 out1:
 613         return err;
 614 }
 615
 616 static void __exit exit_affs_fs(void)
 617 {
 618         unregister_filesystem(&affs_fs_type);
 619         destroy_inodecache();
 620 }
 621
 622 MODULE_DESCRIPTION("Amiga filesystem support for Linux");
 623 MODULE_LICENSE("GPL");
 624
 625 module_init(init_affs_fs)
 626 module_exit(exit_affs_fs)