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