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