git.oblomov.eu Git - linux-2.6/blob - 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_blocks = 0;
  43         inode->i_mapping->a_ops = &omfs_aops;
  44
  45         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
  46         switch (mode & S_IFMT) {
  47         case S_IFDIR:
  48                 inode->i_op = &omfs_dir_inops;
  49                 inode->i_fop = &omfs_dir_operations;
  50                 inode->i_size = sbi->s_sys_blocksize;
  51                 inc_nlink(inode);
  52                 break;
  53         case S_IFREG:
  54                 inode->i_op = &omfs_file_inops;
  55                 inode->i_fop = &omfs_file_operations;
  56                 inode->i_size = 0;
  57                 break;
  58         }
  59
  60         insert_inode_hash(inode);
  61         mark_inode_dirty(inode);
  62         return inode;
  63 fail:
  64         make_bad_inode(inode);
  65         iput(inode);
  66         return ERR_PTR(err);
  67 }
  68
  69 /*
  70  * Update the header checksums for a dirty inode based on its contents.
  71  * Caller is expected to hold the buffer head underlying oi and mark it
  72  * dirty.
  73  */
  74 static void omfs_update_checksums(struct omfs_inode *oi)
  75 {
  76         int xor, i, ofs = 0, count;
  77         u16 crc = 0;
  78         unsigned char *ptr = (unsigned char *) oi;
  79
  80         count = be32_to_cpu(oi->i_head.h_body_size);
  81         ofs = sizeof(struct omfs_header);
  82
  83         crc = crc_itu_t(crc, ptr + ofs, count);
  84         oi->i_head.h_crc = cpu_to_be16(crc);
  85
  86         xor = ptr[0];
  87         for (i = 1; i < OMFS_XOR_COUNT; i++)
  88                 xor ^= ptr[i];
  89
  90         oi->i_head.h_check_xor = xor;
  91 }
  92
  93 static int omfs_write_inode(struct inode *inode, int wait)
  94 {
  95         struct omfs_inode *oi;
  96         struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
  97         struct buffer_head *bh, *bh2;
  98         unsigned int block;
  99         u64 ctime;
 100         int i;
 101         int ret = -EIO;
 102         int sync_failed = 0;
 103
 104         /* get current inode since we may have written sibling ptrs etc. */
 105         block = clus_to_blk(sbi, inode->i_ino);
 106         bh = sb_bread(inode->i_sb, block);
 107         if (!bh)
 108                 goto out;
 109
 110         oi = (struct omfs_inode *) bh->b_data;
 111
 112         oi->i_head.h_self = cpu_to_be64(inode->i_ino);
 113         if (S_ISDIR(inode->i_mode))
 114                 oi->i_type = OMFS_DIR;
 115         else if (S_ISREG(inode->i_mode))
 116                 oi->i_type = OMFS_FILE;
 117         else {
 118                 printk(KERN_WARNING "omfs: unknown file type: %d\n",
 119                         inode->i_mode);
 120                 goto out_brelse;
 121         }
 122
 123         oi->i_head.h_body_size = cpu_to_be32(sbi->s_sys_blocksize -
 124                 sizeof(struct omfs_header));
 125         oi->i_head.h_version = 1;
 126         oi->i_head.h_type = OMFS_INODE_NORMAL;
 127         oi->i_head.h_magic = OMFS_IMAGIC;
 128         oi->i_size = cpu_to_be64(inode->i_size);
 129
 130         ctime = inode->i_ctime.tv_sec * 1000LL +
 131                 ((inode->i_ctime.tv_nsec + 999)/1000);
 132         oi->i_ctime = cpu_to_be64(ctime);
 133
 134         omfs_update_checksums(oi);
 135
 136         mark_buffer_dirty(bh);
 137         if (wait) {
 138                 sync_dirty_buffer(bh);
 139                 if (buffer_req(bh) && !buffer_uptodate(bh))
 140                         sync_failed = 1;
 141         }
 142
 143         /* if mirroring writes, copy to next fsblock */
 144         for (i = 1; i < sbi->s_mirrors; i++) {
 145                 bh2 = sb_bread(inode->i_sb, block + i *
 146                         (sbi->s_blocksize / sbi->s_sys_blocksize));
 147                 if (!bh2)
 148                         goto out_brelse;
 149
 150                 memcpy(bh2->b_data, bh->b_data, bh->b_size);
 151                 mark_buffer_dirty(bh2);
 152                 if (wait) {
 153                         sync_dirty_buffer(bh2);
 154                         if (buffer_req(bh2) && !buffer_uptodate(bh2))
 155                                 sync_failed = 1;
 156                 }
 157                 brelse(bh2);
 158         }
 159         ret = (sync_failed) ? -EIO : 0;
 160 out_brelse:
 161         brelse(bh);
 162 out:
 163         return ret;
 164 }
 165
 166 int omfs_sync_inode(struct inode *inode)
 167 {
 168         return omfs_write_inode(inode, 1);
 169 }
 170
 171 /*
 172  * called when an entry is deleted, need to clear the bits in the
 173  * bitmaps.
 174  */
 175 static void omfs_delete_inode(struct inode *inode)
 176 {
 177         truncate_inode_pages(&inode->i_data, 0);
 178
 179         if (S_ISREG(inode->i_mode)) {
 180                 inode->i_size = 0;
 181                 omfs_shrink_inode(inode);
 182         }
 183
 184         omfs_clear_range(inode->i_sb, inode->i_ino, 2);
 185         clear_inode(inode);
 186 }
 187
 188 struct inode *omfs_iget(struct super_block *sb, ino_t ino)
 189 {
 190         struct omfs_sb_info *sbi = OMFS_SB(sb);
 191         struct omfs_inode *oi;
 192         struct buffer_head *bh;
 193         unsigned int block;
 194         u64 ctime;
 195         unsigned long nsecs;
 196         struct inode *inode;
 197
 198         inode = iget_locked(sb, ino);
 199         if (!inode)
 200                 return ERR_PTR(-ENOMEM);
 201         if (!(inode->i_state & I_NEW))
 202                 return inode;
 203
 204         block = clus_to_blk(sbi, ino);
 205         bh = sb_bread(inode->i_sb, block);
 206         if (!bh)
 207                 goto iget_failed;
 208
 209         oi = (struct omfs_inode *)bh->b_data;
 210
 211         /* check self */
 212         if (ino != be64_to_cpu(oi->i_head.h_self))
 213                 goto fail_bh;
 214
 215         inode->i_uid = sbi->s_uid;
 216         inode->i_gid = sbi->s_gid;
 217
 218         ctime = be64_to_cpu(oi->i_ctime);
 219         nsecs = do_div(ctime, 1000) * 1000L;
 220
 221         inode->i_atime.tv_sec = ctime;
 222         inode->i_mtime.tv_sec = ctime;
 223         inode->i_ctime.tv_sec = ctime;
 224         inode->i_atime.tv_nsec = nsecs;
 225         inode->i_mtime.tv_nsec = nsecs;
 226         inode->i_ctime.tv_nsec = nsecs;
 227
 228         inode->i_mapping->a_ops = &omfs_aops;
 229
 230         switch (oi->i_type) {
 231         case OMFS_DIR:
 232                 inode->i_mode = S_IFDIR | (S_IRWXUGO & ~sbi->s_dmask);
 233                 inode->i_op = &omfs_dir_inops;
 234                 inode->i_fop = &omfs_dir_operations;
 235                 inode->i_size = sbi->s_sys_blocksize;
 236                 inc_nlink(inode);
 237                 break;
 238         case OMFS_FILE:
 239                 inode->i_mode = S_IFREG | (S_IRWXUGO & ~sbi->s_fmask);
 240                 inode->i_fop = &omfs_file_operations;
 241                 inode->i_size = be64_to_cpu(oi->i_size);
 242                 break;
 243         }
 244         brelse(bh);
 245         unlock_new_inode(inode);
 246         return inode;
 247 fail_bh:
 248         brelse(bh);
 249 iget_failed:
 250         iget_failed(inode);
 251         return ERR_PTR(-EIO);
 252 }
 253
 254 static void omfs_put_super(struct super_block *sb)
 255 {
 256         struct omfs_sb_info *sbi = OMFS_SB(sb);
 257         kfree(sbi->s_imap);
 258         kfree(sbi);
 259         sb->s_fs_info = NULL;
 260 }
 261
 262 static int omfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 263 {
 264         struct super_block *s = dentry->d_sb;
 265         struct omfs_sb_info *sbi = OMFS_SB(s);
 266         buf->f_type = OMFS_MAGIC;
 267         buf->f_bsize = sbi->s_blocksize;
 268         buf->f_blocks = sbi->s_num_blocks;
 269         buf->f_files = sbi->s_num_blocks;
 270         buf->f_namelen = OMFS_NAMELEN;
 271
 272         buf->f_bfree = buf->f_bavail = buf->f_ffree =
 273                 omfs_count_free(s);
 274         return 0;
 275 }
 276
 277 static struct super_operations omfs_sops = {
 278         .write_inode    = omfs_write_inode,
 279         .delete_inode   = omfs_delete_inode,
 280         .put_super      = omfs_put_super,
 281         .statfs         = omfs_statfs,
 282         .show_options   = generic_show_options,
 283 };
 284
 285 /*
 286  * For Rio Karma, there is an on-disk free bitmap whose location is
 287  * stored in the root block.  For ReplayTV, there is no such free bitmap
 288  * so we have to walk the tree.  Both inodes and file data are allocated
 289  * from the same map.  This array can be big (300k) so we allocate
 290  * in units of the blocksize.
 291  */
 292 static int omfs_get_imap(struct super_block *sb)
 293 {
 294         int bitmap_size;
 295         int array_size;
 296         int count;
 297         struct omfs_sb_info *sbi = OMFS_SB(sb);
 298         struct buffer_head *bh;
 299         unsigned long **ptr;
 300         sector_t block;
 301
 302         bitmap_size = DIV_ROUND_UP(sbi->s_num_blocks, 8);
 303         array_size = DIV_ROUND_UP(bitmap_size, sb->s_blocksize);
 304
 305         if (sbi->s_bitmap_ino == ~0ULL)
 306                 goto out;
 307
 308         sbi->s_imap_size = array_size;
 309         sbi->s_imap = kzalloc(array_size * sizeof(unsigned long *), GFP_KERNEL);
 310         if (!sbi->s_imap)
 311                 goto nomem;
 312
 313         block = clus_to_blk(sbi, sbi->s_bitmap_ino);
 314         ptr = sbi->s_imap;
 315         for (count = bitmap_size; count > 0; count -= sb->s_blocksize) {
 316                 bh = sb_bread(sb, block++);
 317                 if (!bh)
 318                         goto nomem_free;
 319                 *ptr = kmalloc(sb->s_blocksize, GFP_KERNEL);
 320                 if (!*ptr) {
 321                         brelse(bh);
 322                         goto nomem_free;
 323                 }
 324                 memcpy(*ptr, bh->b_data, sb->s_blocksize);
 325                 if (count < sb->s_blocksize)
 326                         memset((void *)*ptr + count, 0xff,
 327                                 sb->s_blocksize - count);
 328                 brelse(bh);
 329                 ptr++;
 330         }
 331 out:
 332         return 0;
 333
 334 nomem_free:
 335         for (count = 0; count < array_size; count++)
 336                 kfree(sbi->s_imap[count]);
 337
 338         kfree(sbi->s_imap);
 339 nomem:
 340         sbi->s_imap = NULL;
 341         sbi->s_imap_size = 0;
 342         return -ENOMEM;
 343 }
 344
 345 enum {
 346         Opt_uid, Opt_gid, Opt_umask, Opt_dmask, Opt_fmask
 347 };
 348
 349 static match_table_t tokens = {
 350         {Opt_uid, "uid=%u"},
 351         {Opt_gid, "gid=%u"},
 352         {Opt_umask, "umask=%o"},
 353         {Opt_dmask, "dmask=%o"},
 354         {Opt_fmask, "fmask=%o"},
 355 };
 356
 357 static int parse_options(char *options, struct omfs_sb_info *sbi)
 358 {
 359         char *p;
 360         substring_t args[MAX_OPT_ARGS];
 361         int option;
 362
 363         if (!options)
 364                 return 1;
 365
 366         while ((p = strsep(&options, ",")) != NULL) {
 367                 int token;
 368                 if (!*p)
 369                         continue;
 370
 371                 token = match_token(p, tokens, args);
 372                 switch (token) {
 373                 case Opt_uid:
 374                         if (match_int(&args[0], &option))
 375                                 return 0;
 376                         sbi->s_uid = option;
 377                         break;
 378                 case Opt_gid:
 379                         if (match_int(&args[0], &option))
 380                                 return 0;
 381                         sbi->s_gid = option;
 382                         break;
 383                 case Opt_umask:
 384                         if (match_octal(&args[0], &option))
 385                                 return 0;
 386                         sbi->s_fmask = sbi->s_dmask = option;
 387                         break;
 388                 case Opt_dmask:
 389                         if (match_octal(&args[0], &option))
 390                                 return 0;
 391                         sbi->s_dmask = option;
 392                         break;
 393                 case Opt_fmask:
 394                         if (match_octal(&args[0], &option))
 395                                 return 0;
 396                         sbi->s_fmask = option;
 397                         break;
 398                 default:
 399                         return 0;
 400                 }
 401         }
 402         return 1;
 403 }
 404
 405 static int omfs_fill_super(struct super_block *sb, void *data, int silent)
 406 {
 407         struct buffer_head *bh, *bh2;
 408         struct omfs_super_block *omfs_sb;
 409         struct omfs_root_block *omfs_rb;
 410         struct omfs_sb_info *sbi;
 411         struct inode *root;
 412         sector_t start;
 413         int ret = -EINVAL;
 414
 415         save_mount_options(sb, (char *) data);
 416
 417         sbi = kzalloc(sizeof(struct omfs_sb_info), GFP_KERNEL);
 418         if (!sbi)
 419                 return -ENOMEM;
 420
 421         sb->s_fs_info = sbi;
 422
 423         sbi->s_uid = current->uid;
 424         sbi->s_gid = current->gid;
 425         sbi->s_dmask = sbi->s_fmask = current->fs->umask;
 426
 427         if (!parse_options((char *) data, sbi))
 428                 goto end;
 429
 430         sb->s_maxbytes = 0xffffffff;
 431
 432         sb_set_blocksize(sb, 0x200);
 433
 434         bh = sb_bread(sb, 0);
 435         if (!bh)
 436                 goto end;
 437
 438         omfs_sb = (struct omfs_super_block *)bh->b_data;
 439
 440         if (omfs_sb->s_magic != cpu_to_be32(OMFS_MAGIC)) {
 441                 if (!silent)
 442                         printk(KERN_ERR "omfs: Invalid superblock (%x)\n",
 443                                    omfs_sb->s_magic);
 444                 goto out_brelse_bh;
 445         }
 446         sb->s_magic = OMFS_MAGIC;
 447
 448         sbi->s_num_blocks = be64_to_cpu(omfs_sb->s_num_blocks);
 449         sbi->s_blocksize = be32_to_cpu(omfs_sb->s_blocksize);
 450         sbi->s_mirrors = be32_to_cpu(omfs_sb->s_mirrors);
 451         sbi->s_root_ino = be64_to_cpu(omfs_sb->s_root_block);
 452         sbi->s_sys_blocksize = be32_to_cpu(omfs_sb->s_sys_blocksize);
 453         mutex_init(&sbi->s_bitmap_lock);
 454
 455         if (sbi->s_sys_blocksize > PAGE_SIZE) {
 456                 printk(KERN_ERR "omfs: sysblock size (%d) is out of range\n",
 457                         sbi->s_sys_blocksize);
 458                 goto out_brelse_bh;
 459         }
 460
 461         if (sbi->s_blocksize < sbi->s_sys_blocksize ||
 462             sbi->s_blocksize > OMFS_MAX_BLOCK_SIZE) {
 463                 printk(KERN_ERR "omfs: block size (%d) is out of range\n",
 464                         sbi->s_blocksize);
 465                 goto out_brelse_bh;
 466         }
 467
 468         /*
 469          * Use sys_blocksize as the fs block since it is smaller than a
 470          * page while the fs blocksize can be larger.
 471          */
 472         sb_set_blocksize(sb, sbi->s_sys_blocksize);
 473
 474         /*
 475          * ...and the difference goes into a shift.  sys_blocksize is always
 476          * a power of two factor of blocksize.
 477          */
 478         sbi->s_block_shift = get_bitmask_order(sbi->s_blocksize) -
 479                 get_bitmask_order(sbi->s_sys_blocksize);
 480
 481         start = clus_to_blk(sbi, be64_to_cpu(omfs_sb->s_root_block));
 482         bh2 = sb_bread(sb, start);
 483         if (!bh2)
 484                 goto out_brelse_bh;
 485
 486         omfs_rb = (struct omfs_root_block *)bh2->b_data;
 487
 488         sbi->s_bitmap_ino = be64_to_cpu(omfs_rb->r_bitmap);
 489         sbi->s_clustersize = be32_to_cpu(omfs_rb->r_clustersize);
 490
 491         if (sbi->s_num_blocks != be64_to_cpu(omfs_rb->r_num_blocks)) {
 492                 printk(KERN_ERR "omfs: block count discrepancy between "
 493                         "super and root blocks (%llx, %llx)\n",
 494                         (unsigned long long)sbi->s_num_blocks,
 495                         (unsigned long long)be64_to_cpu(omfs_rb->r_num_blocks));
 496                 goto out_brelse_bh2;
 497         }
 498
 499         ret = omfs_get_imap(sb);
 500         if (ret)
 501                 goto out_brelse_bh2;
 502
 503         sb->s_op = &omfs_sops;
 504
 505         root = omfs_iget(sb, be64_to_cpu(omfs_rb->r_root_dir));
 506         if (IS_ERR(root)) {
 507                 ret = PTR_ERR(root);
 508                 goto out_brelse_bh2;
 509         }
 510
 511         sb->s_root = d_alloc_root(root);
 512         if (!sb->s_root) {
 513                 iput(root);
 514                 goto out_brelse_bh2;
 515         }
 516         printk(KERN_DEBUG "omfs: Mounted volume %s\n", omfs_rb->r_name);
 517
 518         ret = 0;
 519 out_brelse_bh2:
 520         brelse(bh2);
 521 out_brelse_bh:
 522         brelse(bh);
 523 end:
 524         return ret;
 525 }
 526
 527 static int omfs_get_sb(struct file_system_type *fs_type,
 528                         int flags, const char *dev_name,
 529                         void *data, struct vfsmount *m)
 530 {
 531         return get_sb_bdev(fs_type, flags, dev_name, data, omfs_fill_super, m);
 532 }
 533
 534 static struct file_system_type omfs_fs_type = {
 535         .owner = THIS_MODULE,
 536         .name = "omfs",
 537         .get_sb = omfs_get_sb,
 538         .kill_sb = kill_block_super,
 539         .fs_flags = FS_REQUIRES_DEV,
 540 };
 541
 542 static int __init init_omfs_fs(void)
 543 {
 544         return register_filesystem(&omfs_fs_type);
 545 }
 546
 547 static void __exit exit_omfs_fs(void)
 548 {
 549         unregister_filesystem(&omfs_fs_type);
 550 }
 551
 552 module_init(init_omfs_fs);
 553 module_exit(exit_omfs_fs);