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