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_destroy_inode(struct inode *inode)
  99 {
 100         kmem_cache_free(affs_inode_cachep, AFFS_I(inode));
 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         mutex_init(&sbi->s_bmlock);
 303         spin_lock_init(&sbi->symlink_lock);
 304
 305         if (!parse_options(data,&uid,&gid,&i,&reserved,&root_block,
 306                                 &blocksize,&sbi->s_prefix,
 307                                 sbi->s_volume, &mount_flags)) {
 308                 printk(KERN_ERR "AFFS: Error parsing options\n");
 309                 kfree(sbi->s_prefix);
 310                 kfree(sbi);
 311                 return -EINVAL;
 312         }
 313         /* N.B. after this point s_prefix must be released */
 314
 315         sbi->s_flags   = mount_flags;
 316         sbi->s_mode    = i;
 317         sbi->s_uid     = uid;
 318         sbi->s_gid     = gid;
 319         sbi->s_reserved= reserved;
 320
 321         /* Get the size of the device in 512-byte blocks.
 322          * If we later see that the partition uses bigger
 323          * blocks, we will have to change it.
 324          */
 325
 326         size = sb->s_bdev->bd_inode->i_size >> 9;
 327         pr_debug("AFFS: initial blocksize=%d, #blocks=%d\n", 512, size);
 328
 329         affs_set_blocksize(sb, PAGE_SIZE);
 330         /* Try to find root block. Its location depends on the block size. */
 331
 332         i = 512;
 333         j = 4096;
 334         if (blocksize > 0) {
 335                 i = j = blocksize;
 336                 size = size / (blocksize / 512);
 337         }
 338         for (blocksize = i, key = 0; blocksize <= j; blocksize <<= 1, size >>= 1) {
 339                 sbi->s_root_block = root_block;
 340                 if (root_block < 0)
 341                         sbi->s_root_block = (reserved + size - 1) / 2;
 342                 pr_debug("AFFS: setting blocksize to %d\n", blocksize);
 343                 affs_set_blocksize(sb, blocksize);
 344                 sbi->s_partition_size = size;
 345
 346                 /* The root block location that was calculated above is not
 347                  * correct if the partition size is an odd number of 512-
 348                  * byte blocks, which will be rounded down to a number of
 349                  * 1024-byte blocks, and if there were an even number of
 350                  * reserved blocks. Ideally, all partition checkers should
 351                  * report the real number of blocks of the real blocksize,
 352                  * but since this just cannot be done, we have to try to
 353                  * find the root block anyways. In the above case, it is one
 354                  * block behind the calculated one. So we check this one, too.
 355                  */
 356                 for (num_bm = 0; num_bm < 2; num_bm++) {
 357                         pr_debug("AFFS: Dev %s, trying root=%u, bs=%d, "
 358                                 "size=%d, reserved=%d\n",
 359                                 sb->s_id,
 360                                 sbi->s_root_block + num_bm,
 361                                 blocksize, size, reserved);
 362                         root_bh = affs_bread(sb, sbi->s_root_block + num_bm);
 363                         if (!root_bh)
 364                                 continue;
 365                         if (!affs_checksum_block(sb, root_bh) &&
 366                             be32_to_cpu(AFFS_ROOT_HEAD(root_bh)->ptype) == T_SHORT &&
 367                             be32_to_cpu(AFFS_ROOT_TAIL(sb, root_bh)->stype) == ST_ROOT) {
 368                                 sbi->s_hashsize    = blocksize / 4 - 56;
 369                                 sbi->s_root_block += num_bm;
 370                                 key                        = 1;
 371                                 goto got_root;
 372                         }
 373                         affs_brelse(root_bh);
 374                         root_bh = NULL;
 375                 }
 376         }
 377         if (!silent)
 378                 printk(KERN_ERR "AFFS: No valid root block on device %s\n",
 379                         sb->s_id);
 380         goto out_error;
 381
 382         /* N.B. after this point bh must be released */
 383 got_root:
 384         root_block = sbi->s_root_block;
 385
 386         /* Find out which kind of FS we have */
 387         boot_bh = sb_bread(sb, 0);
 388         if (!boot_bh) {
 389                 printk(KERN_ERR "AFFS: Cannot read boot block\n");
 390                 goto out_error;
 391         }
 392         memcpy(sig, boot_bh->b_data, 4);
 393         brelse(boot_bh);
 394         chksum = be32_to_cpu(*(__be32 *)sig);
 395
 396         /* Dircache filesystems are compatible with non-dircache ones
 397          * when reading. As long as they aren't supported, writing is
 398          * not recommended.
 399          */
 400         if ((chksum == FS_DCFFS || chksum == MUFS_DCFFS || chksum == FS_DCOFS
 401              || chksum == MUFS_DCOFS) && !(sb->s_flags & MS_RDONLY)) {
 402                 printk(KERN_NOTICE "AFFS: Dircache FS - mounting %s read only\n",
 403                         sb->s_id);
 404                 sb->s_flags |= MS_RDONLY;
 405         }
 406         switch (chksum) {
 407                 case MUFS_FS:
 408                 case MUFS_INTLFFS:
 409                 case MUFS_DCFFS:
 410                         sbi->s_flags |= SF_MUFS;
 411                         /* fall thru */
 412                 case FS_INTLFFS:
 413                 case FS_DCFFS:
 414                         sbi->s_flags |= SF_INTL;
 415                         break;
 416                 case MUFS_FFS:
 417                         sbi->s_flags |= SF_MUFS;
 418                         break;
 419                 case FS_FFS:
 420                         break;
 421                 case MUFS_OFS:
 422                         sbi->s_flags |= SF_MUFS;
 423                         /* fall thru */
 424                 case FS_OFS:
 425                         sbi->s_flags |= SF_OFS;
 426                         sb->s_flags |= MS_NOEXEC;
 427                         break;
 428                 case MUFS_DCOFS:
 429                 case MUFS_INTLOFS:
 430                         sbi->s_flags |= SF_MUFS;
 431                 case FS_DCOFS:
 432                 case FS_INTLOFS:
 433                         sbi->s_flags |= SF_INTL | SF_OFS;
 434                         sb->s_flags |= MS_NOEXEC;
 435                         break;
 436                 default:
 437                         printk(KERN_ERR "AFFS: Unknown filesystem on device %s: %08X\n",
 438                                 sb->s_id, chksum);
 439                         goto out_error;
 440         }
 441
 442         if (mount_flags & SF_VERBOSE) {
 443                 u8 len = AFFS_ROOT_TAIL(sb, root_bh)->disk_name[0];
 444                 printk(KERN_NOTICE "AFFS: Mounting volume \"%.*s\": Type=%.3s\\%c, Blocksize=%d\n",
 445                         len > 31 ? 31 : len,
 446                         AFFS_ROOT_TAIL(sb, root_bh)->disk_name + 1,
 447                         sig, sig[3] + '0', blocksize);
 448         }
 449
 450         sb->s_flags |= MS_NODEV | MS_NOSUID;
 451
 452         sbi->s_data_blksize = sb->s_blocksize;
 453         if (sbi->s_flags & SF_OFS)
 454                 sbi->s_data_blksize -= 24;
 455
 456         /* Keep super block in cache */
 457         sbi->s_root_bh = root_bh;
 458         /* N.B. after this point s_root_bh must be released */
 459
 460         tmp_flags = sb->s_flags;
 461         if (affs_init_bitmap(sb, &tmp_flags))
 462                 goto out_error;
 463         sb->s_flags = tmp_flags;
 464
 465         /* set up enough so that it can read an inode */
 466
 467         root_inode = affs_iget(sb, root_block);
 468         if (IS_ERR(root_inode)) {
 469                 ret = PTR_ERR(root_inode);
 470                 goto out_error_noinode;
 471         }
 472
 473         sb->s_root = d_alloc_root(root_inode);
 474         if (!sb->s_root) {
 475                 printk(KERN_ERR "AFFS: Get root inode failed\n");
 476                 goto out_error;
 477         }
 478         sb->s_root->d_op = &affs_dentry_operations;
 479
 480         pr_debug("AFFS: s_flags=%lX\n",sb->s_flags);
 481         return 0;
 482
 483         /*
 484          * Begin the cascaded cleanup ...
 485          */
 486 out_error:
 487         if (root_inode)
 488                 iput(root_inode);
 489 out_error_noinode:
 490         kfree(sbi->s_bitmap);
 491         affs_brelse(root_bh);
 492         kfree(sbi->s_prefix);
 493         kfree(sbi);
 494         sb->s_fs_info = NULL;
 495         return ret;
 496 }
 497
 498 static int
 499 affs_remount(struct super_block *sb, int *flags, char *data)
 500 {
 501         struct affs_sb_info     *sbi = AFFS_SB(sb);
 502         int                      blocksize;
 503         uid_t                    uid;
 504         gid_t                    gid;
 505         int                      mode;
 506         int                      reserved;
 507         int                      root_block;
 508         unsigned long            mount_flags;
 509         int                      res = 0;
 510         char                    *new_opts = kstrdup(data, GFP_KERNEL);
 511         char                     volume[32];
 512         char                    *prefix = NULL;
 513
 514         pr_debug("AFFS: remount(flags=0x%x,opts=\"%s\")\n",*flags,data);
 515
 516         *flags |= MS_NODIRATIME;
 517
 518         memcpy(volume, sbi->s_volume, 32);
 519         if (!parse_options(data, &uid, &gid, &mode, &reserved, &root_block,
 520                            &blocksize, &prefix, volume,
 521                            &mount_flags)) {
 522                 kfree(prefix);
 523                 kfree(new_opts);
 524                 return -EINVAL;
 525         }
 526
 527         replace_mount_options(sb, new_opts);
 528
 529         sbi->s_flags = mount_flags;
 530         sbi->s_mode  = mode;
 531         sbi->s_uid   = uid;
 532         sbi->s_gid   = gid;
 533         /* protect against readers */
 534         spin_lock(&sbi->symlink_lock);
 535         if (prefix) {
 536                 kfree(sbi->s_prefix);
 537                 sbi->s_prefix = prefix;
 538         }
 539         memcpy(sbi->s_volume, volume, 32);
 540         spin_unlock(&sbi->symlink_lock);
 541
 542         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 543                 return 0;
 544
 545         if (*flags & MS_RDONLY) {
 546                 affs_write_super(sb);
 547                 affs_free_bitmap(sb);
 548         } else
 549                 res = affs_init_bitmap(sb, flags);
 550
 551         return res;
 552 }
 553
 554 static int
 555 affs_statfs(struct dentry *dentry, struct kstatfs *buf)
 556 {
 557         struct super_block *sb = dentry->d_sb;
 558         int              free;
 559         u64              id = huge_encode_dev(sb->s_bdev->bd_dev);
 560
 561         pr_debug("AFFS: statfs() partsize=%d, reserved=%d\n",AFFS_SB(sb)->s_partition_size,
 562              AFFS_SB(sb)->s_reserved);
 563
 564         free          = affs_count_free_blocks(sb);
 565         buf->f_type    = AFFS_SUPER_MAGIC;
 566         buf->f_bsize   = sb->s_blocksize;
 567         buf->f_blocks  = AFFS_SB(sb)->s_partition_size - AFFS_SB(sb)->s_reserved;
 568         buf->f_bfree   = free;
 569         buf->f_bavail  = free;
 570         buf->f_fsid.val[0] = (u32)id;
 571         buf->f_fsid.val[1] = (u32)(id >> 32);
 572         buf->f_namelen = 30;
 573         return 0;
 574 }
 575
 576 static struct dentry *affs_mount(struct file_system_type *fs_type,
 577         int flags, const char *dev_name, void *data)
 578 {
 579         return mount_bdev(fs_type, flags, dev_name, data, affs_fill_super);
 580 }
 581
 582 static struct file_system_type affs_fs_type = {
 583         .owner          = THIS_MODULE,
 584         .name           = "affs",
 585         .mount          = affs_mount,
 586         .kill_sb        = kill_block_super,
 587         .fs_flags       = FS_REQUIRES_DEV,
 588 };
 589
 590 static int __init init_affs_fs(void)
 591 {
 592         int err = init_inodecache();
 593         if (err)
 594                 goto out1;
 595         err = register_filesystem(&affs_fs_type);
 596         if (err)
 597                 goto out;
 598         return 0;
 599 out:
 600         destroy_inodecache();
 601 out1:
 602         return err;
 603 }
 604
 605 static void __exit exit_affs_fs(void)
 606 {
 607         unregister_filesystem(&affs_fs_type);
 608         destroy_inodecache();
 609 }
 610
 611 MODULE_DESCRIPTION("Amiga filesystem support for Linux");
 612 MODULE_LICENSE("GPL");
 613
 614 module_init(init_affs_fs)
 615 module_exit(exit_affs_fs)