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