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