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