kernel/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 <linux/writeback.h>
  21 #include "affs.h"
  22
  23 static int affs_statfs(struct dentry *dentry, struct kstatfs *buf);
  24 static int affs_remount (struct super_block *sb, int *flags, char *data);
  25
  26 static void
  27 affs_commit_super(struct super_block *sb, int wait)
  28 {
  29         struct affs_sb_info *sbi = AFFS_SB(sb);
  30         struct buffer_head *bh = sbi->s_root_bh;
  31         struct affs_root_tail *tail = AFFS_ROOT_TAIL(sb, bh);
  32
  33         lock_buffer(bh);
  34         secs_to_datestamp(get_seconds(), &tail->disk_change);
  35         affs_fix_checksum(sb, bh);
  36         unlock_buffer(bh);
  37
  38         mark_buffer_dirty(bh);
  39         if (wait)
  40                 sync_dirty_buffer(bh);
  41 }
  42
  43 static void
  44 affs_put_super(struct super_block *sb)
  45 {
  46         struct affs_sb_info *sbi = AFFS_SB(sb);
  47         pr_debug("%s()\n", __func__);
  48
  49         cancel_delayed_work_sync(&sbi->sb_work);
  50 }
  51
  52 static int
  53 affs_sync_fs(struct super_block *sb, int wait)
  54 {
  55         affs_commit_super(sb, wait);
  56         return 0;
  57 }
  58
  59 static void flush_superblock(struct work_struct *work)
  60 {
  61         struct affs_sb_info *sbi;
  62         struct super_block *sb;
  63
  64         sbi = container_of(work, struct affs_sb_info, sb_work.work);
  65         sb = sbi->sb;
  66
  67         spin_lock(&sbi->work_lock);
  68         sbi->work_queued = 0;
  69         spin_unlock(&sbi->work_lock);
  70
  71         affs_commit_super(sb, 1);
  72 }
  73
  74 void affs_mark_sb_dirty(struct super_block *sb)
  75 {
  76         struct affs_sb_info *sbi = AFFS_SB(sb);
  77         unsigned long delay;
  78
  79         if (sb->s_flags & MS_RDONLY)
  80                return;
  81
  82         spin_lock(&sbi->work_lock);
  83         if (!sbi->work_queued) {
  84                delay = msecs_to_jiffies(dirty_writeback_interval * 10);
  85                queue_delayed_work(system_long_wq, &sbi->sb_work, delay);
  86                sbi->work_queued = 1;
  87         }
  88         spin_unlock(&sbi->work_lock);
  89 }
  90
  91 static struct kmem_cache * affs_inode_cachep;
  92
  93 static struct inode *affs_alloc_inode(struct super_block *sb)
  94 {
  95         struct affs_inode_info *i;
  96
  97         i = kmem_cache_alloc(affs_inode_cachep, GFP_KERNEL);
  98         if (!i)
  99                 return NULL;
 100
 101         i->vfs_inode.i_version = 1;
 102         i->i_lc = NULL;
 103         i->i_ext_bh = NULL;
 104         i->i_pa_cnt = 0;
 105
 106         return &i->vfs_inode;
 107 }
 108
 109 static void affs_i_callback(struct rcu_head *head)
 110 {
 111         struct inode *inode = container_of(head, struct inode, i_rcu);
 112         kmem_cache_free(affs_inode_cachep, AFFS_I(inode));
 113 }
 114
 115 static void affs_destroy_inode(struct inode *inode)
 116 {
 117         call_rcu(&inode->i_rcu, affs_i_callback);
 118 }
 119
 120 static void init_once(void *foo)
 121 {
 122         struct affs_inode_info *ei = (struct affs_inode_info *) foo;
 123
 124         sema_init(&ei->i_link_lock, 1);
 125         sema_init(&ei->i_ext_lock, 1);
 126         inode_init_once(&ei->vfs_inode);
 127 }
 128
 129 static int __init init_inodecache(void)
 130 {
 131         affs_inode_cachep = kmem_cache_create("affs_inode_cache",
 132                                              sizeof(struct affs_inode_info),
 133                                              0, (SLAB_RECLAIM_ACCOUNT|
 134                                                 SLAB_MEM_SPREAD),
 135                                              init_once);
 136         if (affs_inode_cachep == NULL)
 137                 return -ENOMEM;
 138         return 0;
 139 }
 140
 141 static void destroy_inodecache(void)
 142 {
 143         /*
 144          * Make sure all delayed rcu free inodes are flushed before we
 145          * destroy cache.
 146          */
 147         rcu_barrier();
 148         kmem_cache_destroy(affs_inode_cachep);
 149 }
 150
 151 static const struct super_operations affs_sops = {
 152         .alloc_inode    = affs_alloc_inode,
 153         .destroy_inode  = affs_destroy_inode,
 154         .write_inode    = affs_write_inode,
 155         .evict_inode    = affs_evict_inode,
 156         .put_super      = affs_put_super,
 157         .sync_fs        = affs_sync_fs,
 158         .statfs         = affs_statfs,
 159         .remount_fs     = affs_remount,
 160         .show_options   = generic_show_options,
 161 };
 162
 163 enum {
 164         Opt_bs, Opt_mode, Opt_mufs, Opt_notruncate, Opt_prefix, Opt_protect,
 165         Opt_reserved, Opt_root, Opt_setgid, Opt_setuid,
 166         Opt_verbose, Opt_volume, Opt_ignore, Opt_err,
 167 };
 168
 169 static const match_table_t tokens = {
 170         {Opt_bs, "bs=%u"},
 171         {Opt_mode, "mode=%o"},
 172         {Opt_mufs, "mufs"},
 173         {Opt_notruncate, "nofilenametruncate"},
 174         {Opt_prefix, "prefix=%s"},
 175         {Opt_protect, "protect"},
 176         {Opt_reserved, "reserved=%u"},
 177         {Opt_root, "root=%u"},
 178         {Opt_setgid, "setgid=%u"},
 179         {Opt_setuid, "setuid=%u"},
 180         {Opt_verbose, "verbose"},
 181         {Opt_volume, "volume=%s"},
 182         {Opt_ignore, "grpquota"},
 183         {Opt_ignore, "noquota"},
 184         {Opt_ignore, "quota"},
 185         {Opt_ignore, "usrquota"},
 186         {Opt_err, NULL},
 187 };
 188
 189 static int
 190 parse_options(char *options, kuid_t *uid, kgid_t *gid, int *mode, int *reserved, s32 *root,
 191                 int *blocksize, char **prefix, char *volume, unsigned long *mount_opts)
 192 {
 193         char *p;
 194         substring_t args[MAX_OPT_ARGS];
 195
 196         /* Fill in defaults */
 197
 198         *uid        = current_uid();
 199         *gid        = current_gid();
 200         *reserved   = 2;
 201         *root       = -1;
 202         *blocksize  = -1;
 203         volume[0]   = ':';
 204         volume[1]   = 0;
 205         *mount_opts = 0;
 206         if (!options)
 207                 return 1;
 208
 209         while ((p = strsep(&options, ",")) != NULL) {
 210                 int token, n, option;
 211                 if (!*p)
 212                         continue;
 213
 214                 token = match_token(p, tokens, args);
 215                 switch (token) {
 216                 case Opt_bs:
 217                         if (match_int(&args[0], &n))
 218                                 return 0;
 219                         if (n != 512 && n != 1024 && n != 2048
 220                             && n != 4096) {
 221                                 pr_warn("Invalid blocksize (512, 1024, 2048, 4096 allowed)\n");
 222                                 return 0;
 223                         }
 224                         *blocksize = n;
 225                         break;
 226                 case Opt_mode:
 227                         if (match_octal(&args[0], &option))
 228                                 return 0;
 229                         *mode = option & 0777;
 230                         affs_set_opt(*mount_opts, SF_SETMODE);
 231                         break;
 232                 case Opt_mufs:
 233                         affs_set_opt(*mount_opts, SF_MUFS);
 234                         break;
 235                 case Opt_notruncate:
 236                         affs_set_opt(*mount_opts, SF_NO_TRUNCATE);
 237                         break;
 238                 case Opt_prefix:
 239                         *prefix = match_strdup(&args[0]);
 240                         if (!*prefix)
 241                                 return 0;
 242                         affs_set_opt(*mount_opts, SF_PREFIX);
 243                         break;
 244                 case Opt_protect:
 245                         affs_set_opt(*mount_opts, SF_IMMUTABLE);
 246                         break;
 247                 case Opt_reserved:
 248                         if (match_int(&args[0], reserved))
 249                                 return 0;
 250                         break;
 251                 case Opt_root:
 252                         if (match_int(&args[0], root))
 253                                 return 0;
 254                         break;
 255                 case Opt_setgid:
 256                         if (match_int(&args[0], &option))
 257                                 return 0;
 258                         *gid = make_kgid(current_user_ns(), option);
 259                         if (!gid_valid(*gid))
 260                                 return 0;
 261                         affs_set_opt(*mount_opts, SF_SETGID);
 262                         break;
 263                 case Opt_setuid:
 264                         if (match_int(&args[0], &option))
 265                                 return 0;
 266                         *uid = make_kuid(current_user_ns(), option);
 267                         if (!uid_valid(*uid))
 268                                 return 0;
 269                         affs_set_opt(*mount_opts, SF_SETUID);
 270                         break;
 271                 case Opt_verbose:
 272                         affs_set_opt(*mount_opts, SF_VERBOSE);
 273                         break;
 274                 case Opt_volume: {
 275                         char *vol = match_strdup(&args[0]);
 276                         if (!vol)
 277                                 return 0;
 278                         strlcpy(volume, vol, 32);
 279                         kfree(vol);
 280                         break;
 281                 }
 282                 case Opt_ignore:
 283                         /* Silently ignore the quota options */
 284                         break;
 285                 default:
 286                         pr_warn("Unrecognized mount option \"%s\" or missing value\n",
 287                                 p);
 288                         return 0;
 289                 }
 290         }
 291         return 1;
 292 }
 293
 294 /* This function definitely needs to be split up. Some fine day I'll
 295  * hopefully have the guts to do so. Until then: sorry for the mess.
 296  */
 297
 298 static int affs_fill_super(struct super_block *sb, void *data, int silent)
 299 {
 300         struct affs_sb_info     *sbi;
 301         struct buffer_head      *root_bh = NULL;
 302         struct buffer_head      *boot_bh;
 303         struct inode            *root_inode = NULL;
 304         s32                      root_block;
 305         int                      size, blocksize;
 306         u32                      chksum;
 307         int                      num_bm;
 308         int                      i, j;
 309         kuid_t                   uid;
 310         kgid_t                   gid;
 311         int                      reserved;
 312         unsigned long            mount_flags;
 313         int                      tmp_flags;     /* fix remount prototype... */
 314         u8                       sig[4];
 315         int                      ret;
 316
 317         save_mount_options(sb, data);
 318
 319         pr_debug("read_super(%s)\n", data ? (const char *)data : "no options");
 320
 321         sb->s_magic             = AFFS_SUPER_MAGIC;
 322         sb->s_op                = &affs_sops;
 323         sb->s_flags |= MS_NODIRATIME;
 324
 325         sbi = kzalloc(sizeof(struct affs_sb_info), GFP_KERNEL);
 326         if (!sbi)
 327                 return -ENOMEM;
 328
 329         sb->s_fs_info = sbi;
 330         sbi->sb = sb;
 331         mutex_init(&sbi->s_bmlock);
 332         spin_lock_init(&sbi->symlink_lock);
 333         spin_lock_init(&sbi->work_lock);
 334         INIT_DELAYED_WORK(&sbi->sb_work, flush_superblock);
 335
 336         if (!parse_options(data,&uid,&gid,&i,&reserved,&root_block,
 337                                 &blocksize,&sbi->s_prefix,
 338                                 sbi->s_volume, &mount_flags)) {
 339                 pr_err("Error parsing options\n");
 340                 return -EINVAL;
 341         }
 342         /* N.B. after this point s_prefix must be released */
 343
 344         sbi->s_flags   = mount_flags;
 345         sbi->s_mode    = i;
 346         sbi->s_uid     = uid;
 347         sbi->s_gid     = gid;
 348         sbi->s_reserved= reserved;
 349
 350         /* Get the size of the device in 512-byte blocks.
 351          * If we later see that the partition uses bigger
 352          * blocks, we will have to change it.
 353          */
 354
 355         size = sb->s_bdev->bd_inode->i_size >> 9;
 356         pr_debug("initial blocksize=%d, #blocks=%d\n", 512, size);
 357
 358         affs_set_blocksize(sb, PAGE_SIZE);
 359         /* Try to find root block. Its location depends on the block size. */
 360
 361         i = 512;
 362         j = 4096;
 363         if (blocksize > 0) {
 364                 i = j = blocksize;
 365                 size = size / (blocksize / 512);
 366         }
 367         for (blocksize = i; blocksize <= j; blocksize <<= 1, size >>= 1) {
 368                 sbi->s_root_block = root_block;
 369                 if (root_block < 0)
 370                         sbi->s_root_block = (reserved + size - 1) / 2;
 371                 pr_debug("setting blocksize to %d\n", blocksize);
 372                 affs_set_blocksize(sb, blocksize);
 373                 sbi->s_partition_size = size;
 374
 375                 /* The root block location that was calculated above is not
 376                  * correct if the partition size is an odd number of 512-
 377                  * byte blocks, which will be rounded down to a number of
 378                  * 1024-byte blocks, and if there were an even number of
 379                  * reserved blocks. Ideally, all partition checkers should
 380                  * report the real number of blocks of the real blocksize,
 381                  * but since this just cannot be done, we have to try to
 382                  * find the root block anyways. In the above case, it is one
 383                  * block behind the calculated one. So we check this one, too.
 384                  */
 385                 for (num_bm = 0; num_bm < 2; num_bm++) {
 386                         pr_debug("Dev %s, trying root=%u, bs=%d, "
 387                                 "size=%d, reserved=%d\n",
 388                                 sb->s_id,
 389                                 sbi->s_root_block + num_bm,
 390                                 blocksize, size, reserved);
 391                         root_bh = affs_bread(sb, sbi->s_root_block + num_bm);
 392                         if (!root_bh)
 393                                 continue;
 394                         if (!affs_checksum_block(sb, root_bh) &&
 395                             be32_to_cpu(AFFS_ROOT_HEAD(root_bh)->ptype) == T_SHORT &&
 396                             be32_to_cpu(AFFS_ROOT_TAIL(sb, root_bh)->stype) == ST_ROOT) {
 397                                 sbi->s_hashsize    = blocksize / 4 - 56;
 398                                 sbi->s_root_block += num_bm;
 399                                 goto got_root;
 400                         }
 401                         affs_brelse(root_bh);
 402                         root_bh = NULL;
 403                 }
 404         }
 405         if (!silent)
 406                 pr_err("No valid root block on device %s\n", sb->s_id);
 407         return -EINVAL;
 408
 409         /* N.B. after this point bh must be released */
 410 got_root:
 411         /* Keep super block in cache */
 412         sbi->s_root_bh = root_bh;
 413         root_block = sbi->s_root_block;
 414
 415         /* Find out which kind of FS we have */
 416         boot_bh = sb_bread(sb, 0);
 417         if (!boot_bh) {
 418                 pr_err("Cannot read boot block\n");
 419                 return -EINVAL;
 420         }
 421         memcpy(sig, boot_bh->b_data, 4);
 422         brelse(boot_bh);
 423         chksum = be32_to_cpu(*(__be32 *)sig);
 424
 425         /* Dircache filesystems are compatible with non-dircache ones
 426          * when reading. As long as they aren't supported, writing is
 427          * not recommended.
 428          */
 429         if ((chksum == FS_DCFFS || chksum == MUFS_DCFFS || chksum == FS_DCOFS
 430              || chksum == MUFS_DCOFS) && !(sb->s_flags & MS_RDONLY)) {
 431                 pr_notice("Dircache FS - mounting %s read only\n", sb->s_id);
 432                 sb->s_flags |= MS_RDONLY;
 433         }
 434         switch (chksum) {
 435         case MUFS_FS:
 436         case MUFS_INTLFFS:
 437         case MUFS_DCFFS:
 438                 affs_set_opt(sbi->s_flags, SF_MUFS);
 439                 /* fall thru */
 440         case FS_INTLFFS:
 441         case FS_DCFFS:
 442                 affs_set_opt(sbi->s_flags, SF_INTL);
 443                 break;
 444         case MUFS_FFS:
 445                 affs_set_opt(sbi->s_flags, SF_MUFS);
 446                 break;
 447         case FS_FFS:
 448                 break;
 449         case MUFS_OFS:
 450                 affs_set_opt(sbi->s_flags, SF_MUFS);
 451                 /* fall thru */
 452         case FS_OFS:
 453                 affs_set_opt(sbi->s_flags, SF_OFS);
 454                 sb->s_flags |= MS_NOEXEC;
 455                 break;
 456         case MUFS_DCOFS:
 457         case MUFS_INTLOFS:
 458                 affs_set_opt(sbi->s_flags, SF_MUFS);
 459         case FS_DCOFS:
 460         case FS_INTLOFS:
 461                 affs_set_opt(sbi->s_flags, SF_INTL);
 462                 affs_set_opt(sbi->s_flags, SF_OFS);
 463                 sb->s_flags |= MS_NOEXEC;
 464                 break;
 465         default:
 466                 pr_err("Unknown filesystem on device %s: %08X\n",
 467                        sb->s_id, chksum);
 468                 return -EINVAL;
 469         }
 470
 471         if (affs_test_opt(mount_flags, SF_VERBOSE)) {
 472                 u8 len = AFFS_ROOT_TAIL(sb, root_bh)->disk_name[0];
 473                 pr_notice("Mounting volume \"%.*s\": Type=%.3s\\%c, Blocksize=%d\n",
 474                         len > 31 ? 31 : len,
 475                         AFFS_ROOT_TAIL(sb, root_bh)->disk_name + 1,
 476                         sig, sig[3] + '0', blocksize);
 477         }
 478
 479         sb->s_flags |= MS_NODEV | MS_NOSUID;
 480
 481         sbi->s_data_blksize = sb->s_blocksize;
 482         if (affs_test_opt(sbi->s_flags, SF_OFS))
 483                 sbi->s_data_blksize -= 24;
 484
 485         tmp_flags = sb->s_flags;
 486         ret = affs_init_bitmap(sb, &tmp_flags);
 487         if (ret)
 488                 return ret;
 489         sb->s_flags = tmp_flags;
 490
 491         /* set up enough so that it can read an inode */
 492
 493         root_inode = affs_iget(sb, root_block);
 494         if (IS_ERR(root_inode))
 495                 return PTR_ERR(root_inode);
 496
 497         if (affs_test_opt(AFFS_SB(sb)->s_flags, SF_INTL))
 498                 sb->s_d_op = &affs_intl_dentry_operations;
 499         else
 500                 sb->s_d_op = &affs_dentry_operations;
 501
 502         sb->s_root = d_make_root(root_inode);
 503         if (!sb->s_root) {
 504                 pr_err("AFFS: Get root inode failed\n");
 505                 return -ENOMEM;
 506         }
 507
 508         pr_debug("s_flags=%lX\n", sb->s_flags);
 509         return 0;
 510 }
 511
 512 static int
 513 affs_remount(struct super_block *sb, int *flags, char *data)
 514 {
 515         struct affs_sb_info     *sbi = AFFS_SB(sb);
 516         int                      blocksize;
 517         kuid_t                   uid;
 518         kgid_t                   gid;
 519         int                      mode;
 520         int                      reserved;
 521         int                      root_block;
 522         unsigned long            mount_flags;
 523         int                      res = 0;
 524         char                    *new_opts;
 525         char                     volume[32];
 526         char                    *prefix = NULL;
 527
 528         new_opts = kstrdup(data, GFP_KERNEL);
 529         if (!new_opts)
 530                 return -ENOMEM;
 531
 532         pr_debug("%s(flags=0x%x,opts=\"%s\")\n", __func__, *flags, data);
 533
 534         sync_filesystem(sb);
 535         *flags |= MS_NODIRATIME;
 536
 537         memcpy(volume, sbi->s_volume, 32);
 538         if (!parse_options(data, &uid, &gid, &mode, &reserved, &root_block,
 539                            &blocksize, &prefix, volume,
 540                            &mount_flags)) {
 541                 kfree(prefix);
 542                 kfree(new_opts);
 543                 return -EINVAL;
 544         }
 545
 546         flush_delayed_work(&sbi->sb_work);
 547         replace_mount_options(sb, new_opts);
 548
 549         sbi->s_flags = mount_flags;
 550         sbi->s_mode  = mode;
 551         sbi->s_uid   = uid;
 552         sbi->s_gid   = gid;
 553         /* protect against readers */
 554         spin_lock(&sbi->symlink_lock);
 555         if (prefix) {
 556                 kfree(sbi->s_prefix);
 557                 sbi->s_prefix = prefix;
 558         }
 559         memcpy(sbi->s_volume, volume, 32);
 560         spin_unlock(&sbi->symlink_lock);
 561
 562         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 563                 return 0;
 564
 565         if (*flags & MS_RDONLY)
 566                 affs_free_bitmap(sb);
 567         else
 568                 res = affs_init_bitmap(sb, flags);
 569
 570         return res;
 571 }
 572
 573 static int
 574 affs_statfs(struct dentry *dentry, struct kstatfs *buf)
 575 {
 576         struct super_block *sb = dentry->d_sb;
 577         int              free;
 578         u64              id = huge_encode_dev(sb->s_bdev->bd_dev);
 579
 580         pr_debug("%s() partsize=%d, reserved=%d\n",
 581                  __func__, AFFS_SB(sb)->s_partition_size,
 582                  AFFS_SB(sb)->s_reserved);
 583
 584         free          = affs_count_free_blocks(sb);
 585         buf->f_type    = AFFS_SUPER_MAGIC;
 586         buf->f_bsize   = sb->s_blocksize;
 587         buf->f_blocks  = AFFS_SB(sb)->s_partition_size - AFFS_SB(sb)->s_reserved;
 588         buf->f_bfree   = free;
 589         buf->f_bavail  = free;
 590         buf->f_fsid.val[0] = (u32)id;
 591         buf->f_fsid.val[1] = (u32)(id >> 32);
 592         buf->f_namelen = AFFSNAMEMAX;
 593         return 0;
 594 }
 595
 596 static struct dentry *affs_mount(struct file_system_type *fs_type,
 597         int flags, const char *dev_name, void *data)
 598 {
 599         return mount_bdev(fs_type, flags, dev_name, data, affs_fill_super);
 600 }
 601
 602 static void affs_kill_sb(struct super_block *sb)
 603 {
 604         struct affs_sb_info *sbi = AFFS_SB(sb);
 605         kill_block_super(sb);
 606         if (sbi) {
 607                 affs_free_bitmap(sb);
 608                 affs_brelse(sbi->s_root_bh);
 609                 kfree(sbi->s_prefix);
 610                 mutex_destroy(&sbi->s_bmlock);
 611                 kfree(sbi);
 612         }
 613 }
 614
 615 static struct file_system_type affs_fs_type = {
 616         .owner          = THIS_MODULE,
 617         .name           = "affs",
 618         .mount          = affs_mount,
 619         .kill_sb        = affs_kill_sb,
 620         .fs_flags       = FS_REQUIRES_DEV,
 621 };
 622 MODULE_ALIAS_FS("affs");
 623
 624 static int __init init_affs_fs(void)
 625 {
 626         int err = init_inodecache();
 627         if (err)
 628                 goto out1;
 629         err = register_filesystem(&affs_fs_type);
 630         if (err)
 631                 goto out;
 632         return 0;
 633 out:
 634         destroy_inodecache();
 635 out1:
 636         return err;
 637 }
 638
 639 static void __exit exit_affs_fs(void)
 640 {
 641         unregister_filesystem(&affs_fs_type);
 642         destroy_inodecache();
 643 }
 644
 645 MODULE_DESCRIPTION("Amiga filesystem support for Linux");
 646 MODULE_LICENSE("GPL");
 647
 648 module_init(init_affs_fs)
 649 module_exit(exit_affs_fs)