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