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