fs/omfs/inode.c

   1 /*
   2  * Optimized MPEG FS - inode and super operations.
   3  * Copyright (C) 2006 Bob Copeland <me@bobcopeland.com>
   4  * Released under GPL v2.
   5  */
   6 #include <linux/module.h>
   7 #include <linux/sched.h>
   8 #include <linux/slab.h>
   9 #include <linux/fs.h>
  10 #include <linux/vfs.h>
  11 #include <linux/cred.h>
  12 #include <linux/parser.h>
  13 #include <linux/buffer_head.h>
  14 #include <linux/vmalloc.h>
  15 #include <linux/writeback.h>
  16 #include <linux/seq_file.h>
  17 #include <linux/crc-itu-t.h>
  18 #include "omfs.h"
  19
  20 MODULE_AUTHOR("Bob Copeland <me@bobcopeland.com>");
  21 MODULE_DESCRIPTION("OMFS (ReplayTV/Karma) Filesystem for Linux");
  22 MODULE_LICENSE("GPL");
  23
  24 struct buffer_head *omfs_bread(struct super_block *sb, sector_t block)
  25 {
  26         struct omfs_sb_info *sbi = OMFS_SB(sb);
  27         if (block >= sbi->s_num_blocks)
  28                 return NULL;
  29
  30         return sb_bread(sb, clus_to_blk(sbi, block));
  31 }
  32
  33 struct inode *omfs_new_inode(struct inode *dir, umode_t mode)
  34 {
  35         struct inode *inode;
  36         u64 new_block;
  37         int err;
  38         int len;
  39         struct omfs_sb_info *sbi = OMFS_SB(dir->i_sb);
  40
  41         inode = new_inode(dir->i_sb);
  42         if (!inode)
  43                 return ERR_PTR(-ENOMEM);
  44
  45         err = omfs_allocate_range(dir->i_sb, sbi->s_mirrors, sbi->s_mirrors,
  46                         &new_block, &len);
  47         if (err)
  48                 goto fail;
  49
  50         inode->i_ino = new_block;
  51         inode_init_owner(inode, NULL, mode);
  52         inode->i_mapping->a_ops = &omfs_aops;
  53
  54         inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
  55         switch (mode & S_IFMT) {
  56         case S_IFDIR:
  57                 inode->i_op = &omfs_dir_inops;
  58                 inode->i_fop = &omfs_dir_operations;
  59                 inode->i_size = sbi->s_sys_blocksize;
  60                 inc_nlink(inode);
  61                 break;
  62         case S_IFREG:
  63                 inode->i_op = &omfs_file_inops;
  64                 inode->i_fop = &omfs_file_operations;
  65                 inode->i_size = 0;
  66                 break;
  67         }
  68
  69         insert_inode_hash(inode);
  70         mark_inode_dirty(inode);
  71         return inode;
  72 fail:
  73         make_bad_inode(inode);
  74         iput(inode);
  75         return ERR_PTR(err);
  76 }
  77
  78 /*
  79  * Update the header checksums for a dirty inode based on its contents.
  80  * Caller is expected to hold the buffer head underlying oi and mark it
  81  * dirty.
  82  */
  83 static void omfs_update_checksums(struct omfs_inode *oi)
  84 {
  85         int xor, i, ofs = 0, count;
  86         u16 crc = 0;
  87         unsigned char *ptr = (unsigned char *) oi;
  88
  89         count = be32_to_cpu(oi->i_head.h_body_size);
  90         ofs = sizeof(struct omfs_header);
  91
  92         crc = crc_itu_t(crc, ptr + ofs, count);
  93         oi->i_head.h_crc = cpu_to_be16(crc);
  94
  95         xor = ptr[0];
  96         for (i = 1; i < OMFS_XOR_COUNT; i++)
  97                 xor ^= ptr[i];
  98
  99         oi->i_head.h_check_xor = xor;
 100 }
 101
 102 static int __omfs_write_inode(struct inode *inode, int wait)
 103 {
 104         struct omfs_inode *oi;
 105         struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
 106         struct buffer_head *bh, *bh2;
 107         u64 ctime;
 108         int i;
 109         int ret = -EIO;
 110         int sync_failed = 0;
 111
 112         /* get current inode since we may have written sibling ptrs etc. */
 113         bh = omfs_bread(inode->i_sb, inode->i_ino);
 114         if (!bh)
 115                 goto out;
 116
 117         oi = (struct omfs_inode *) bh->b_data;
 118
 119         oi->i_head.h_self = cpu_to_be64(inode->i_ino);
 120         if (S_ISDIR(inode->i_mode))
 121                 oi->i_type = OMFS_DIR;
 122         else if (S_ISREG(inode->i_mode))
 123                 oi->i_type = OMFS_FILE;
 124         else {
 125                 printk(KERN_WARNING "omfs: unknown file type: %d\n",
 126                         inode->i_mode);
 127                 goto out_brelse;
 128         }
 129
 130         oi->i_head.h_body_size = cpu_to_be32(sbi->s_sys_blocksize -
 131                 sizeof(struct omfs_header));
 132         oi->i_head.h_version = 1;
 133         oi->i_head.h_type = OMFS_INODE_NORMAL;
 134         oi->i_head.h_magic = OMFS_IMAGIC;
 135         oi->i_size = cpu_to_be64(inode->i_size);
 136
 137         ctime = inode->i_ctime.tv_sec * 1000LL +
 138                 ((inode->i_ctime.tv_nsec + 999)/1000);
 139         oi->i_ctime = cpu_to_be64(ctime);
 140
 141         omfs_update_checksums(oi);
 142
 143         mark_buffer_dirty(bh);
 144         if (wait) {
 145                 sync_dirty_buffer(bh);
 146                 if (buffer_req(bh) && !buffer_uptodate(bh))
 147                         sync_failed = 1;
 148         }
 149
 150         /* if mirroring writes, copy to next fsblock */
 151         for (i = 1; i < sbi->s_mirrors; i++) {
 152                 bh2 = omfs_bread(inode->i_sb, inode->i_ino + i);
 153                 if (!bh2)
 154                         goto out_brelse;
 155
 156                 memcpy(bh2->b_data, bh->b_data, bh->b_size);
 157                 mark_buffer_dirty(bh2);
 158                 if (wait) {
 159                         sync_dirty_buffer(bh2);
 160                         if (buffer_req(bh2) && !buffer_uptodate(bh2))
 161                                 sync_failed = 1;
 162                 }
 163                 brelse(bh2);
 164         }
 165         ret = (sync_failed) ? -EIO : 0;
 166 out_brelse:
 167         brelse(bh);
 168 out:
 169         return ret;
 170 }
 171
 172 static int omfs_write_inode(struct inode *inode, struct writeback_control *wbc)
 173 {
 174         return __omfs_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
 175 }
 176
 177 int omfs_sync_inode(struct inode *inode)
 178 {
 179         return __omfs_write_inode(inode, 1);
 180 }
 181
 182 /*
 183  * called when an entry is deleted, need to clear the bits in the
 184  * bitmaps.
 185  */
 186 static void omfs_evict_inode(struct inode *inode)
 187 {
 188         truncate_inode_pages_final(&inode->i_data);
 189         clear_inode(inode);
 190
 191         if (inode->i_nlink)
 192                 return;
 193
 194         if (S_ISREG(inode->i_mode)) {
 195                 inode->i_size = 0;
 196                 omfs_shrink_inode(inode);
 197         }
 198
 199         omfs_clear_range(inode->i_sb, inode->i_ino, 2);
 200 }
 201
 202 struct inode *omfs_iget(struct super_block *sb, ino_t ino)
 203 {
 204         struct omfs_sb_info *sbi = OMFS_SB(sb);
 205         struct omfs_inode *oi;
 206         struct buffer_head *bh;
 207         u64 ctime;
 208         unsigned long nsecs;
 209         struct inode *inode;
 210
 211         inode = iget_locked(sb, ino);
 212         if (!inode)
 213                 return ERR_PTR(-ENOMEM);
 214         if (!(inode->i_state & I_NEW))
 215                 return inode;
 216
 217         bh = omfs_bread(inode->i_sb, ino);
 218         if (!bh)
 219                 goto iget_failed;
 220
 221         oi = (struct omfs_inode *)bh->b_data;
 222
 223         /* check self */
 224         if (ino != be64_to_cpu(oi->i_head.h_self))
 225                 goto fail_bh;
 226
 227         inode->i_uid = sbi->s_uid;
 228         inode->i_gid = sbi->s_gid;
 229
 230         ctime = be64_to_cpu(oi->i_ctime);
 231         nsecs = do_div(ctime, 1000) * 1000L;
 232
 233         inode->i_atime.tv_sec = ctime;
 234         inode->i_mtime.tv_sec = ctime;
 235         inode->i_ctime.tv_sec = ctime;
 236         inode->i_atime.tv_nsec = nsecs;
 237         inode->i_mtime.tv_nsec = nsecs;
 238         inode->i_ctime.tv_nsec = nsecs;
 239
 240         inode->i_mapping->a_ops = &omfs_aops;
 241
 242         switch (oi->i_type) {
 243         case OMFS_DIR:
 244                 inode->i_mode = S_IFDIR | (S_IRWXUGO & ~sbi->s_dmask);
 245                 inode->i_op = &omfs_dir_inops;
 246                 inode->i_fop = &omfs_dir_operations;
 247                 inode->i_size = sbi->s_sys_blocksize;
 248                 inc_nlink(inode);
 249                 break;
 250         case OMFS_FILE:
 251                 inode->i_mode = S_IFREG | (S_IRWXUGO & ~sbi->s_fmask);
 252                 inode->i_fop = &omfs_file_operations;
 253                 inode->i_size = be64_to_cpu(oi->i_size);
 254                 break;
 255         }
 256         brelse(bh);
 257         unlock_new_inode(inode);
 258         return inode;
 259 fail_bh:
 260         brelse(bh);
 261 iget_failed:
 262         iget_failed(inode);
 263         return ERR_PTR(-EIO);
 264 }
 265
 266 static void omfs_put_super(struct super_block *sb)
 267 {
 268         struct omfs_sb_info *sbi = OMFS_SB(sb);
 269         kfree(sbi->s_imap);
 270         kfree(sbi);
 271         sb->s_fs_info = NULL;
 272 }
 273
 274 static int omfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 275 {
 276         struct super_block *s = dentry->d_sb;
 277         struct omfs_sb_info *sbi = OMFS_SB(s);
 278         u64 id = huge_encode_dev(s->s_bdev->bd_dev);
 279
 280         buf->f_type = OMFS_MAGIC;
 281         buf->f_bsize = sbi->s_blocksize;
 282         buf->f_blocks = sbi->s_num_blocks;
 283         buf->f_files = sbi->s_num_blocks;
 284         buf->f_namelen = OMFS_NAMELEN;
 285         buf->f_fsid.val[0] = (u32)id;
 286         buf->f_fsid.val[1] = (u32)(id >> 32);
 287
 288         buf->f_bfree = buf->f_bavail = buf->f_ffree =
 289                 omfs_count_free(s);
 290
 291         return 0;
 292 }
 293
 294 /*
 295  * Display the mount options in /proc/mounts.
 296  */
 297 static int omfs_show_options(struct seq_file *m, struct dentry *root)
 298 {
 299         struct omfs_sb_info *sbi = OMFS_SB(root->d_sb);
 300         umode_t cur_umask = current_umask();
 301
 302         if (!uid_eq(sbi->s_uid, current_uid()))
 303                 seq_printf(m, ",uid=%u",
 304                            from_kuid_munged(&init_user_ns, sbi->s_uid));
 305         if (!gid_eq(sbi->s_gid, current_gid()))
 306                 seq_printf(m, ",gid=%u",
 307                            from_kgid_munged(&init_user_ns, sbi->s_gid));
 308
 309         if (sbi->s_dmask == sbi->s_fmask) {
 310                 if (sbi->s_fmask != cur_umask)
 311                         seq_printf(m, ",umask=%o", sbi->s_fmask);
 312         } else {
 313                 if (sbi->s_dmask != cur_umask)
 314                         seq_printf(m, ",dmask=%o", sbi->s_dmask);
 315                 if (sbi->s_fmask != cur_umask)
 316                         seq_printf(m, ",fmask=%o", sbi->s_fmask);
 317         }
 318
 319         return 0;
 320 }
 321
 322 static const struct super_operations omfs_sops = {
 323         .write_inode    = omfs_write_inode,
 324         .evict_inode    = omfs_evict_inode,
 325         .put_super      = omfs_put_super,
 326         .statfs         = omfs_statfs,
 327         .show_options   = omfs_show_options,
 328 };
 329
 330 /*
 331  * For Rio Karma, there is an on-disk free bitmap whose location is
 332  * stored in the root block.  For ReplayTV, there is no such free bitmap
 333  * so we have to walk the tree.  Both inodes and file data are allocated
 334  * from the same map.  This array can be big (300k) so we allocate
 335  * in units of the blocksize.
 336  */
 337 static int omfs_get_imap(struct super_block *sb)
 338 {
 339         unsigned int bitmap_size, array_size;
 340         int count;
 341         struct omfs_sb_info *sbi = OMFS_SB(sb);
 342         struct buffer_head *bh;
 343         unsigned long **ptr;
 344         sector_t block;
 345
 346         bitmap_size = DIV_ROUND_UP(sbi->s_num_blocks, 8);
 347         array_size = DIV_ROUND_UP(bitmap_size, sb->s_blocksize);
 348
 349         if (sbi->s_bitmap_ino == ~0ULL)
 350                 goto out;
 351
 352         sbi->s_imap_size = array_size;
 353         sbi->s_imap = kcalloc(array_size, sizeof(unsigned long *), GFP_KERNEL);
 354         if (!sbi->s_imap)
 355                 goto nomem;
 356
 357         block = clus_to_blk(sbi, sbi->s_bitmap_ino);
 358         if (block >= sbi->s_num_blocks)
 359                 goto nomem;
 360
 361         ptr = sbi->s_imap;
 362         for (count = bitmap_size; count > 0; count -= sb->s_blocksize) {
 363                 bh = sb_bread(sb, block++);
 364                 if (!bh)
 365                         goto nomem_free;
 366                 *ptr = kmalloc(sb->s_blocksize, GFP_KERNEL);
 367                 if (!*ptr) {
 368                         brelse(bh);
 369                         goto nomem_free;
 370                 }
 371                 memcpy(*ptr, bh->b_data, sb->s_blocksize);
 372                 if (count < sb->s_blocksize)
 373                         memset((void *)*ptr + count, 0xff,
 374                                 sb->s_blocksize - count);
 375                 brelse(bh);
 376                 ptr++;
 377         }
 378 out:
 379         return 0;
 380
 381 nomem_free:
 382         for (count = 0; count < array_size; count++)
 383                 kfree(sbi->s_imap[count]);
 384
 385         kfree(sbi->s_imap);
 386 nomem:
 387         sbi->s_imap = NULL;
 388         sbi->s_imap_size = 0;
 389         return -ENOMEM;
 390 }
 391
 392 enum {
 393         Opt_uid, Opt_gid, Opt_umask, Opt_dmask, Opt_fmask, Opt_err
 394 };
 395
 396 static const match_table_t tokens = {
 397         {Opt_uid, "uid=%u"},
 398         {Opt_gid, "gid=%u"},
 399         {Opt_umask, "umask=%o"},
 400         {Opt_dmask, "dmask=%o"},
 401         {Opt_fmask, "fmask=%o"},
 402         {Opt_err, NULL},
 403 };
 404
 405 static int parse_options(char *options, struct omfs_sb_info *sbi)
 406 {
 407         char *p;
 408         substring_t args[MAX_OPT_ARGS];
 409         int option;
 410
 411         if (!options)
 412                 return 1;
 413
 414         while ((p = strsep(&options, ",")) != NULL) {
 415                 int token;
 416                 if (!*p)
 417                         continue;
 418
 419                 token = match_token(p, tokens, args);
 420                 switch (token) {
 421                 case Opt_uid:
 422                         if (match_int(&args[0], &option))
 423                                 return 0;
 424                         sbi->s_uid = make_kuid(current_user_ns(), option);
 425                         if (!uid_valid(sbi->s_uid))
 426                                 return 0;
 427                         break;
 428                 case Opt_gid:
 429                         if (match_int(&args[0], &option))
 430                                 return 0;
 431                         sbi->s_gid = make_kgid(current_user_ns(), option);
 432                         if (!gid_valid(sbi->s_gid))
 433                                 return 0;
 434                         break;
 435                 case Opt_umask:
 436                         if (match_octal(&args[0], &option))
 437                                 return 0;
 438                         sbi->s_fmask = sbi->s_dmask = option;
 439                         break;
 440                 case Opt_dmask:
 441                         if (match_octal(&args[0], &option))
 442                                 return 0;
 443                         sbi->s_dmask = option;
 444                         break;
 445                 case Opt_fmask:
 446                         if (match_octal(&args[0], &option))
 447                                 return 0;
 448                         sbi->s_fmask = option;
 449                         break;
 450                 default:
 451                         return 0;
 452                 }
 453         }
 454         return 1;
 455 }
 456
 457 static int omfs_fill_super(struct super_block *sb, void *data, int silent)
 458 {
 459         struct buffer_head *bh, *bh2;
 460         struct omfs_super_block *omfs_sb;
 461         struct omfs_root_block *omfs_rb;
 462         struct omfs_sb_info *sbi;
 463         struct inode *root;
 464         int ret = -EINVAL;
 465
 466         sbi = kzalloc(sizeof(struct omfs_sb_info), GFP_KERNEL);
 467         if (!sbi)
 468                 return -ENOMEM;
 469
 470         sb->s_fs_info = sbi;
 471
 472         sbi->s_uid = current_uid();
 473         sbi->s_gid = current_gid();
 474         sbi->s_dmask = sbi->s_fmask = current_umask();
 475
 476         if (!parse_options((char *) data, sbi))
 477                 goto end;
 478
 479         sb->s_maxbytes = 0xffffffff;
 480
 481         sb_set_blocksize(sb, 0x200);
 482
 483         bh = sb_bread(sb, 0);
 484         if (!bh)
 485                 goto end;
 486
 487         omfs_sb = (struct omfs_super_block *)bh->b_data;
 488
 489         if (omfs_sb->s_magic != cpu_to_be32(OMFS_MAGIC)) {
 490                 if (!silent)
 491                         printk(KERN_ERR "omfs: Invalid superblock (%x)\n",
 492                                    omfs_sb->s_magic);
 493                 goto out_brelse_bh;
 494         }
 495         sb->s_magic = OMFS_MAGIC;
 496
 497         sbi->s_num_blocks = be64_to_cpu(omfs_sb->s_num_blocks);
 498         sbi->s_blocksize = be32_to_cpu(omfs_sb->s_blocksize);
 499         sbi->s_mirrors = be32_to_cpu(omfs_sb->s_mirrors);
 500         sbi->s_root_ino = be64_to_cpu(omfs_sb->s_root_block);
 501         sbi->s_sys_blocksize = be32_to_cpu(omfs_sb->s_sys_blocksize);
 502         mutex_init(&sbi->s_bitmap_lock);
 503
 504         if (sbi->s_num_blocks > OMFS_MAX_BLOCKS) {
 505                 printk(KERN_ERR "omfs: sysblock number (%llx) is out of range\n",
 506                        (unsigned long long)sbi->s_num_blocks);
 507                 goto out_brelse_bh;
 508         }
 509
 510         if (sbi->s_sys_blocksize > PAGE_SIZE) {
 511                 printk(KERN_ERR "omfs: sysblock size (%d) is out of range\n",
 512                         sbi->s_sys_blocksize);
 513                 goto out_brelse_bh;
 514         }
 515
 516         if (sbi->s_blocksize < sbi->s_sys_blocksize ||
 517             sbi->s_blocksize > OMFS_MAX_BLOCK_SIZE) {
 518                 printk(KERN_ERR "omfs: block size (%d) is out of range\n",
 519                         sbi->s_blocksize);
 520                 goto out_brelse_bh;
 521         }
 522
 523         /*
 524          * Use sys_blocksize as the fs block since it is smaller than a
 525          * page while the fs blocksize can be larger.
 526          */
 527         sb_set_blocksize(sb, sbi->s_sys_blocksize);
 528
 529         /*
 530          * ...and the difference goes into a shift.  sys_blocksize is always
 531          * a power of two factor of blocksize.
 532          */
 533         sbi->s_block_shift = get_bitmask_order(sbi->s_blocksize) -
 534                 get_bitmask_order(sbi->s_sys_blocksize);
 535
 536         bh2 = omfs_bread(sb, be64_to_cpu(omfs_sb->s_root_block));
 537         if (!bh2)
 538                 goto out_brelse_bh;
 539
 540         omfs_rb = (struct omfs_root_block *)bh2->b_data;
 541
 542         sbi->s_bitmap_ino = be64_to_cpu(omfs_rb->r_bitmap);
 543         sbi->s_clustersize = be32_to_cpu(omfs_rb->r_clustersize);
 544
 545         if (sbi->s_num_blocks != be64_to_cpu(omfs_rb->r_num_blocks)) {
 546                 printk(KERN_ERR "omfs: block count discrepancy between "
 547                         "super and root blocks (%llx, %llx)\n",
 548                         (unsigned long long)sbi->s_num_blocks,
 549                         (unsigned long long)be64_to_cpu(omfs_rb->r_num_blocks));
 550                 goto out_brelse_bh2;
 551         }
 552
 553         if (sbi->s_bitmap_ino != ~0ULL &&
 554             sbi->s_bitmap_ino > sbi->s_num_blocks) {
 555                 printk(KERN_ERR "omfs: free space bitmap location is corrupt "
 556                         "(%llx, total blocks %llx)\n",
 557                         (unsigned long long) sbi->s_bitmap_ino,
 558                         (unsigned long long) sbi->s_num_blocks);
 559                 goto out_brelse_bh2;
 560         }
 561         if (sbi->s_clustersize < 1 ||
 562             sbi->s_clustersize > OMFS_MAX_CLUSTER_SIZE) {
 563                 printk(KERN_ERR "omfs: cluster size out of range (%d)",
 564                         sbi->s_clustersize);
 565                 goto out_brelse_bh2;
 566         }
 567
 568         ret = omfs_get_imap(sb);
 569         if (ret)
 570                 goto out_brelse_bh2;
 571
 572         sb->s_op = &omfs_sops;
 573
 574         root = omfs_iget(sb, be64_to_cpu(omfs_rb->r_root_dir));
 575         if (IS_ERR(root)) {
 576                 ret = PTR_ERR(root);
 577                 goto out_brelse_bh2;
 578         }
 579
 580         sb->s_root = d_make_root(root);
 581         if (!sb->s_root) {
 582                 ret = -ENOMEM;
 583                 goto out_brelse_bh2;
 584         }
 585         printk(KERN_DEBUG "omfs: Mounted volume %s\n", omfs_rb->r_name);
 586
 587         ret = 0;
 588 out_brelse_bh2:
 589         brelse(bh2);
 590 out_brelse_bh:
 591         brelse(bh);
 592 end:
 593         if (ret)
 594                 kfree(sbi);
 595         return ret;
 596 }
 597
 598 static struct dentry *omfs_mount(struct file_system_type *fs_type,
 599                         int flags, const char *dev_name, void *data)
 600 {
 601         return mount_bdev(fs_type, flags, dev_name, data, omfs_fill_super);
 602 }
 603
 604 static struct file_system_type omfs_fs_type = {
 605         .owner = THIS_MODULE,
 606         .name = "omfs",
 607         .mount = omfs_mount,
 608         .kill_sb = kill_block_super,
 609         .fs_flags = FS_REQUIRES_DEV,
 610 };
 611 MODULE_ALIAS_FS("omfs");
 612
 613 static int __init init_omfs_fs(void)
 614 {
 615         return register_filesystem(&omfs_fs_type);
 616 }
 617
 618 static void __exit exit_omfs_fs(void)
 619 {
 620         unregister_filesystem(&omfs_fs_type);
 621 }
 622
 623 module_init(init_omfs_fs);
 624 module_exit(exit_omfs_fs);