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         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 = -EINVAL;
 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         goto out_error;
 411
 412         /* N.B. after this point bh must be released */
 413 got_root:
 414         root_block = sbi->s_root_block;
 415
 416         /* Find out which kind of FS we have */
 417         boot_bh = sb_bread(sb, 0);
 418         if (!boot_bh) {
 419                 printk(KERN_ERR "AFFS: Cannot read boot block\n");
 420                 goto out_error;
 421         }
 422         memcpy(sig, boot_bh->b_data, 4);
 423         brelse(boot_bh);
 424         chksum = be32_to_cpu(*(__be32 *)sig);
 425
 426         /* Dircache filesystems are compatible with non-dircache ones
 427          * when reading. As long as they aren't supported, writing is
 428          * not recommended.
 429          */
 430         if ((chksum == FS_DCFFS || chksum == MUFS_DCFFS || chksum == FS_DCOFS
 431              || chksum == MUFS_DCOFS) && !(sb->s_flags & MS_RDONLY)) {
 432                 printk(KERN_NOTICE "AFFS: Dircache FS - mounting %s read only\n",
 433                         sb->s_id);
 434                 sb->s_flags |= MS_RDONLY;
 435         }
 436         switch (chksum) {
 437                 case MUFS_FS:
 438                 case MUFS_INTLFFS:
 439                 case MUFS_DCFFS:
 440                         sbi->s_flags |= SF_MUFS;
 441                         /* fall thru */
 442                 case FS_INTLFFS:
 443                 case FS_DCFFS:
 444                         sbi->s_flags |= SF_INTL;
 445                         break;
 446                 case MUFS_FFS:
 447                         sbi->s_flags |= SF_MUFS;
 448                         break;
 449                 case FS_FFS:
 450                         break;
 451                 case MUFS_OFS:
 452                         sbi->s_flags |= SF_MUFS;
 453                         /* fall thru */
 454                 case FS_OFS:
 455                         sbi->s_flags |= SF_OFS;
 456                         sb->s_flags |= MS_NOEXEC;
 457                         break;
 458                 case MUFS_DCOFS:
 459                 case MUFS_INTLOFS:
 460                         sbi->s_flags |= SF_MUFS;
 461                 case FS_DCOFS:
 462                 case FS_INTLOFS:
 463                         sbi->s_flags |= SF_INTL | SF_OFS;
 464                         sb->s_flags |= MS_NOEXEC;
 465                         break;
 466                 default:
 467                         printk(KERN_ERR "AFFS: Unknown filesystem on device %s: %08X\n",
 468                                 sb->s_id, chksum);
 469                         goto out_error;
 470         }
 471
 472         if (mount_flags & SF_VERBOSE) {
 473                 u8 len = AFFS_ROOT_TAIL(sb, root_bh)->disk_name[0];
 474                 printk(KERN_NOTICE "AFFS: Mounting volume \"%.*s\": Type=%.3s\\%c, Blocksize=%d\n",
 475                         len > 31 ? 31 : len,
 476                         AFFS_ROOT_TAIL(sb, root_bh)->disk_name + 1,
 477                         sig, sig[3] + '0', blocksize);
 478         }
 479
 480         sb->s_flags |= MS_NODEV | MS_NOSUID;
 481
 482         sbi->s_data_blksize = sb->s_blocksize;
 483         if (sbi->s_flags & SF_OFS)
 484                 sbi->s_data_blksize -= 24;
 485
 486         /* Keep super block in cache */
 487         sbi->s_root_bh = root_bh;
 488         /* N.B. after this point s_root_bh must be released */
 489
 490         tmp_flags = sb->s_flags;
 491         if (affs_init_bitmap(sb, &tmp_flags))
 492                 goto out_error;
 493         sb->s_flags = tmp_flags;
 494
 495         /* set up enough so that it can read an inode */
 496
 497         root_inode = affs_iget(sb, root_block);
 498         if (IS_ERR(root_inode)) {
 499                 ret = PTR_ERR(root_inode);
 500                 goto out_error;
 501         }
 502
 503         if (AFFS_SB(sb)->s_flags & SF_INTL)
 504                 sb->s_d_op = &affs_intl_dentry_operations;
 505         else
 506                 sb->s_d_op = &affs_dentry_operations;
 507
 508         sb->s_root = d_make_root(root_inode);
 509         if (!sb->s_root) {
 510                 printk(KERN_ERR "AFFS: Get root inode failed\n");
 511                 goto out_error;
 512         }
 513
 514         pr_debug("AFFS: s_flags=%lX\n",sb->s_flags);
 515         return 0;
 516
 517         /*
 518          * Begin the cascaded cleanup ...
 519          */
 520 out_error:
 521         kfree(sbi->s_bitmap);
 522         affs_brelse(root_bh);
 523         kfree(sbi->s_prefix);
 524         kfree(sbi);
 525         sb->s_fs_info = NULL;
 526         return ret;
 527 }
 528
 529 static int
 530 affs_remount(struct super_block *sb, int *flags, char *data)
 531 {
 532         struct affs_sb_info     *sbi = AFFS_SB(sb);
 533         int                      blocksize;
 534         kuid_t                   uid;
 535         kgid_t                   gid;
 536         int                      mode;
 537         int                      reserved;
 538         int                      root_block;
 539         unsigned long            mount_flags;
 540         int                      res = 0;
 541         char                    *new_opts = kstrdup(data, GFP_KERNEL);
 542         char                     volume[32];
 543         char                    *prefix = NULL;
 544
 545         pr_debug("AFFS: remount(flags=0x%x,opts=\"%s\")\n",*flags,data);
 546
 547         *flags |= MS_NODIRATIME;
 548
 549         memcpy(volume, sbi->s_volume, 32);
 550         if (!parse_options(data, &uid, &gid, &mode, &reserved, &root_block,
 551                            &blocksize, &prefix, volume,
 552                            &mount_flags)) {
 553                 kfree(prefix);
 554                 kfree(new_opts);
 555                 return -EINVAL;
 556         }
 557
 558         flush_delayed_work_sync(&sbi->sb_work);
 559         replace_mount_options(sb, new_opts);
 560
 561         sbi->s_flags = mount_flags;
 562         sbi->s_mode  = mode;
 563         sbi->s_uid   = uid;
 564         sbi->s_gid   = gid;
 565         /* protect against readers */
 566         spin_lock(&sbi->symlink_lock);
 567         if (prefix) {
 568                 kfree(sbi->s_prefix);
 569                 sbi->s_prefix = prefix;
 570         }
 571         memcpy(sbi->s_volume, volume, 32);
 572         spin_unlock(&sbi->symlink_lock);
 573
 574         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 575                 return 0;
 576
 577         if (*flags & MS_RDONLY)
 578                 affs_free_bitmap(sb);
 579         else
 580                 res = affs_init_bitmap(sb, flags);
 581
 582         return res;
 583 }
 584
 585 static int
 586 affs_statfs(struct dentry *dentry, struct kstatfs *buf)
 587 {
 588         struct super_block *sb = dentry->d_sb;
 589         int              free;
 590         u64              id = huge_encode_dev(sb->s_bdev->bd_dev);
 591
 592         pr_debug("AFFS: statfs() partsize=%d, reserved=%d\n",AFFS_SB(sb)->s_partition_size,
 593              AFFS_SB(sb)->s_reserved);
 594
 595         free          = affs_count_free_blocks(sb);
 596         buf->f_type    = AFFS_SUPER_MAGIC;
 597         buf->f_bsize   = sb->s_blocksize;
 598         buf->f_blocks  = AFFS_SB(sb)->s_partition_size - AFFS_SB(sb)->s_reserved;
 599         buf->f_bfree   = free;
 600         buf->f_bavail  = free;
 601         buf->f_fsid.val[0] = (u32)id;
 602         buf->f_fsid.val[1] = (u32)(id >> 32);
 603         buf->f_namelen = 30;
 604         return 0;
 605 }
 606
 607 static struct dentry *affs_mount(struct file_system_type *fs_type,
 608         int flags, const char *dev_name, void *data)
 609 {
 610         return mount_bdev(fs_type, flags, dev_name, data, affs_fill_super);
 611 }
 612
 613 static struct file_system_type affs_fs_type = {
 614         .owner          = THIS_MODULE,
 615         .name           = "affs",
 616         .mount          = affs_mount,
 617         .kill_sb        = kill_block_super,
 618         .fs_flags       = FS_REQUIRES_DEV,
 619 };
 620
 621 static int __init init_affs_fs(void)
 622 {
 623         int err = init_inodecache();
 624         if (err)
 625                 goto out1;
 626         err = register_filesystem(&affs_fs_type);
 627         if (err)
 628                 goto out;
 629         return 0;
 630 out:
 631         destroy_inodecache();
 632 out1:
 633         return err;
 634 }
 635
 636 static void __exit exit_affs_fs(void)
 637 {
 638         unregister_filesystem(&affs_fs_type);
 639         destroy_inodecache();
 640 }
 641
 642 MODULE_DESCRIPTION("Amiga filesystem support for Linux");
 643 MODULE_LICENSE("GPL");
 644
 645 module_init(init_affs_fs)
 646 module_exit(exit_affs_fs)