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