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