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 buffer_head *omfs_bread(struct super_block *sb, sector_t block)
  23 {
  24         struct omfs_sb_info *sbi = OMFS_SB(sb);
  25         if (block >= sbi->s_num_blocks)
  26                 return NULL;
  27
  28         return sb_bread(sb, clus_to_blk(sbi, block));
  29 }
  30
  31 struct inode *omfs_new_inode(struct inode *dir, umode_t mode)
  32 {
  33         struct inode *inode;
  34         u64 new_block;
  35         int err;
  36         int len;
  37         struct omfs_sb_info *sbi = OMFS_SB(dir->i_sb);
  38
  39         inode = new_inode(dir->i_sb);
  40         if (!inode)
  41                 return ERR_PTR(-ENOMEM);
  42
  43         err = omfs_allocate_range(dir->i_sb, sbi->s_mirrors, sbi->s_mirrors,
  44                         &new_block, &len);
  45         if (err)
  46                 goto fail;
  47
  48         inode->i_ino = new_block;
  49         inode_init_owner(inode, NULL, mode);
  50         inode->i_mapping->a_ops = &omfs_aops;
  51
  52         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
  53         switch (mode & S_IFMT) {
  54         case S_IFDIR:
  55                 inode->i_op = &omfs_dir_inops;
  56                 inode->i_fop = &omfs_dir_operations;
  57                 inode->i_size = sbi->s_sys_blocksize;
  58                 inc_nlink(inode);
  59                 break;
  60         case S_IFREG:
  61                 inode->i_op = &omfs_file_inops;
  62                 inode->i_fop = &omfs_file_operations;
  63                 inode->i_size = 0;
  64                 break;
  65         }
  66
  67         insert_inode_hash(inode);
  68         mark_inode_dirty(inode);
  69         return inode;
  70 fail:
  71         make_bad_inode(inode);
  72         iput(inode);
  73         return ERR_PTR(err);
  74 }
  75
  76 /*
  77  * Update the header checksums for a dirty inode based on its contents.
  78  * Caller is expected to hold the buffer head underlying oi and mark it
  79  * dirty.
  80  */
  81 static void omfs_update_checksums(struct omfs_inode *oi)
  82 {
  83         int xor, i, ofs = 0, count;
  84         u16 crc = 0;
  85         unsigned char *ptr = (unsigned char *) oi;
  86
  87         count = be32_to_cpu(oi->i_head.h_body_size);
  88         ofs = sizeof(struct omfs_header);
  89
  90         crc = crc_itu_t(crc, ptr + ofs, count);
  91         oi->i_head.h_crc = cpu_to_be16(crc);
  92
  93         xor = ptr[0];
  94         for (i = 1; i < OMFS_XOR_COUNT; i++)
  95                 xor ^= ptr[i];
  96
  97         oi->i_head.h_check_xor = xor;
  98 }
  99
 100 static int __omfs_write_inode(struct inode *inode, int wait)
 101 {
 102         struct omfs_inode *oi;
 103         struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
 104         struct buffer_head *bh, *bh2;
 105         u64 ctime;
 106         int i;
 107         int ret = -EIO;
 108         int sync_failed = 0;
 109
 110         /* get current inode since we may have written sibling ptrs etc. */
 111         bh = omfs_bread(inode->i_sb, inode->i_ino);
 112         if (!bh)
 113                 goto out;
 114
 115         oi = (struct omfs_inode *) bh->b_data;
 116
 117         oi->i_head.h_self = cpu_to_be64(inode->i_ino);
 118         if (S_ISDIR(inode->i_mode))
 119                 oi->i_type = OMFS_DIR;
 120         else if (S_ISREG(inode->i_mode))
 121                 oi->i_type = OMFS_FILE;
 122         else {
 123                 printk(KERN_WARNING "omfs: unknown file type: %d\n",
 124                         inode->i_mode);
 125                 goto out_brelse;
 126         }
 127
 128         oi->i_head.h_body_size = cpu_to_be32(sbi->s_sys_blocksize -
 129                 sizeof(struct omfs_header));
 130         oi->i_head.h_version = 1;
 131         oi->i_head.h_type = OMFS_INODE_NORMAL;
 132         oi->i_head.h_magic = OMFS_IMAGIC;
 133         oi->i_size = cpu_to_be64(inode->i_size);
 134
 135         ctime = inode->i_ctime.tv_sec * 1000LL +
 136                 ((inode->i_ctime.tv_nsec + 999)/1000);
 137         oi->i_ctime = cpu_to_be64(ctime);
 138
 139         omfs_update_checksums(oi);
 140
 141         mark_buffer_dirty(bh);
 142         if (wait) {
 143                 sync_dirty_buffer(bh);
 144                 if (buffer_req(bh) && !buffer_uptodate(bh))
 145                         sync_failed = 1;
 146         }
 147
 148         /* if mirroring writes, copy to next fsblock */
 149         for (i = 1; i < sbi->s_mirrors; i++) {
 150                 bh2 = omfs_bread(inode->i_sb, inode->i_ino + i);
 151                 if (!bh2)
 152                         goto out_brelse;
 153
 154                 memcpy(bh2->b_data, bh->b_data, bh->b_size);
 155                 mark_buffer_dirty(bh2);
 156                 if (wait) {
 157                         sync_dirty_buffer(bh2);
 158                         if (buffer_req(bh2) && !buffer_uptodate(bh2))
 159                                 sync_failed = 1;
 160                 }
 161                 brelse(bh2);
 162         }
 163         ret = (sync_failed) ? -EIO : 0;
 164 out_brelse:
 165         brelse(bh);
 166 out:
 167         return ret;
 168 }
 169
 170 static int omfs_write_inode(struct inode *inode, struct writeback_control *wbc)
 171 {
 172         return __omfs_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
 173 }
 174
 175 int omfs_sync_inode(struct inode *inode)
 176 {
 177         return __omfs_write_inode(inode, 1);
 178 }
 179
 180 /*
 181  * called when an entry is deleted, need to clear the bits in the
 182  * bitmaps.
 183  */
 184 static void omfs_evict_inode(struct inode *inode)
 185 {
 186         truncate_inode_pages_final(&inode->i_data);
 187         clear_inode(inode);
 188
 189         if (inode->i_nlink)
 190                 return;
 191
 192         if (S_ISREG(inode->i_mode)) {
 193                 inode->i_size = 0;
 194                 omfs_shrink_inode(inode);
 195         }
 196
 197         omfs_clear_range(inode->i_sb, inode->i_ino, 2);
 198 }
 199
 200 struct inode *omfs_iget(struct super_block *sb, ino_t ino)
 201 {
 202         struct omfs_sb_info *sbi = OMFS_SB(sb);
 203         struct omfs_inode *oi;
 204         struct buffer_head *bh;
 205         u64 ctime;
 206         unsigned long nsecs;
 207         struct inode *inode;
 208
 209         inode = iget_locked(sb, ino);
 210         if (!inode)
 211                 return ERR_PTR(-ENOMEM);
 212         if (!(inode->i_state & I_NEW))
 213                 return inode;
 214
 215         bh = omfs_bread(inode->i_sb, ino);
 216         if (!bh)
 217                 goto iget_failed;
 218
 219         oi = (struct omfs_inode *)bh->b_data;
 220
 221         /* check self */
 222         if (ino != be64_to_cpu(oi->i_head.h_self))
 223                 goto fail_bh;
 224
 225         inode->i_uid = sbi->s_uid;
 226         inode->i_gid = sbi->s_gid;
 227
 228         ctime = be64_to_cpu(oi->i_ctime);
 229         nsecs = do_div(ctime, 1000) * 1000L;
 230
 231         inode->i_atime.tv_sec = ctime;
 232         inode->i_mtime.tv_sec = ctime;
 233         inode->i_ctime.tv_sec = ctime;
 234         inode->i_atime.tv_nsec = nsecs;
 235         inode->i_mtime.tv_nsec = nsecs;
 236         inode->i_ctime.tv_nsec = nsecs;
 237
 238         inode->i_mapping->a_ops = &omfs_aops;
 239
 240         switch (oi->i_type) {
 241         case OMFS_DIR:
 242                 inode->i_mode = S_IFDIR | (S_IRWXUGO & ~sbi->s_dmask);
 243                 inode->i_op = &omfs_dir_inops;
 244                 inode->i_fop = &omfs_dir_operations;
 245                 inode->i_size = sbi->s_sys_blocksize;
 246                 inc_nlink(inode);
 247                 break;
 248         case OMFS_FILE:
 249                 inode->i_mode = S_IFREG | (S_IRWXUGO & ~sbi->s_fmask);
 250                 inode->i_fop = &omfs_file_operations;
 251                 inode->i_size = be64_to_cpu(oi->i_size);
 252                 break;
 253         }
 254         brelse(bh);
 255         unlock_new_inode(inode);
 256         return inode;
 257 fail_bh:
 258         brelse(bh);
 259 iget_failed:
 260         iget_failed(inode);
 261         return ERR_PTR(-EIO);
 262 }
 263
 264 static void omfs_put_super(struct super_block *sb)
 265 {
 266         struct omfs_sb_info *sbi = OMFS_SB(sb);
 267         kfree(sbi->s_imap);
 268         kfree(sbi);
 269         sb->s_fs_info = NULL;
 270 }
 271
 272 static int omfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 273 {
 274         struct super_block *s = dentry->d_sb;
 275         struct omfs_sb_info *sbi = OMFS_SB(s);
 276         u64 id = huge_encode_dev(s->s_bdev->bd_dev);
 277
 278         buf->f_type = OMFS_MAGIC;
 279         buf->f_bsize = sbi->s_blocksize;
 280         buf->f_blocks = sbi->s_num_blocks;
 281         buf->f_files = sbi->s_num_blocks;
 282         buf->f_namelen = OMFS_NAMELEN;
 283         buf->f_fsid.val[0] = (u32)id;
 284         buf->f_fsid.val[1] = (u32)(id >> 32);
 285
 286         buf->f_bfree = buf->f_bavail = buf->f_ffree =
 287                 omfs_count_free(s);
 288
 289         return 0;
 290 }
 291
 292 static const struct super_operations omfs_sops = {
 293         .write_inode    = omfs_write_inode,
 294         .evict_inode    = omfs_evict_inode,
 295         .put_super      = omfs_put_super,
 296         .statfs         = omfs_statfs,
 297         .show_options   = generic_show_options,
 298 };
 299
 300 /*
 301  * For Rio Karma, there is an on-disk free bitmap whose location is
 302  * stored in the root block.  For ReplayTV, there is no such free bitmap
 303  * so we have to walk the tree.  Both inodes and file data are allocated
 304  * from the same map.  This array can be big (300k) so we allocate
 305  * in units of the blocksize.
 306  */
 307 static int omfs_get_imap(struct super_block *sb)
 308 {
 309         unsigned int bitmap_size, array_size;
 310         int count;
 311         struct omfs_sb_info *sbi = OMFS_SB(sb);
 312         struct buffer_head *bh;
 313         unsigned long **ptr;
 314         sector_t block;
 315
 316         bitmap_size = DIV_ROUND_UP(sbi->s_num_blocks, 8);
 317         array_size = DIV_ROUND_UP(bitmap_size, sb->s_blocksize);
 318
 319         if (sbi->s_bitmap_ino == ~0ULL)
 320                 goto out;
 321
 322         sbi->s_imap_size = array_size;
 323         sbi->s_imap = kcalloc(array_size, sizeof(unsigned long *), GFP_KERNEL);
 324         if (!sbi->s_imap)
 325                 goto nomem;
 326
 327         block = clus_to_blk(sbi, sbi->s_bitmap_ino);
 328         if (block >= sbi->s_num_blocks)
 329                 goto nomem;
 330
 331         ptr = sbi->s_imap;
 332         for (count = bitmap_size; count > 0; count -= sb->s_blocksize) {
 333                 bh = sb_bread(sb, block++);
 334                 if (!bh)
 335                         goto nomem_free;
 336                 *ptr = kmalloc(sb->s_blocksize, GFP_KERNEL);
 337                 if (!*ptr) {
 338                         brelse(bh);
 339                         goto nomem_free;
 340                 }
 341                 memcpy(*ptr, bh->b_data, sb->s_blocksize);
 342                 if (count < sb->s_blocksize)
 343                         memset((void *)*ptr + count, 0xff,
 344                                 sb->s_blocksize - count);
 345                 brelse(bh);
 346                 ptr++;
 347         }
 348 out:
 349         return 0;
 350
 351 nomem_free:
 352         for (count = 0; count < array_size; count++)
 353                 kfree(sbi->s_imap[count]);
 354
 355         kfree(sbi->s_imap);
 356 nomem:
 357         sbi->s_imap = NULL;
 358         sbi->s_imap_size = 0;
 359         return -ENOMEM;
 360 }
 361
 362 enum {
 363         Opt_uid, Opt_gid, Opt_umask, Opt_dmask, Opt_fmask, Opt_err
 364 };
 365
 366 static const match_table_t tokens = {
 367         {Opt_uid, "uid=%u"},
 368         {Opt_gid, "gid=%u"},
 369         {Opt_umask, "umask=%o"},
 370         {Opt_dmask, "dmask=%o"},
 371         {Opt_fmask, "fmask=%o"},
 372         {Opt_err, NULL},
 373 };
 374
 375 static int parse_options(char *options, struct omfs_sb_info *sbi)
 376 {
 377         char *p;
 378         substring_t args[MAX_OPT_ARGS];
 379         int option;
 380
 381         if (!options)
 382                 return 1;
 383
 384         while ((p = strsep(&options, ",")) != NULL) {
 385                 int token;
 386                 if (!*p)
 387                         continue;
 388
 389                 token = match_token(p, tokens, args);
 390                 switch (token) {
 391                 case Opt_uid:
 392                         if (match_int(&args[0], &option))
 393                                 return 0;
 394                         sbi->s_uid = make_kuid(current_user_ns(), option);
 395                         if (!uid_valid(sbi->s_uid))
 396                                 return 0;
 397                         break;
 398                 case Opt_gid:
 399                         if (match_int(&args[0], &option))
 400                                 return 0;
 401                         sbi->s_gid = make_kgid(current_user_ns(), option);
 402                         if (!gid_valid(sbi->s_gid))
 403                                 return 0;
 404                         break;
 405                 case Opt_umask:
 406                         if (match_octal(&args[0], &option))
 407                                 return 0;
 408                         sbi->s_fmask = sbi->s_dmask = option;
 409                         break;
 410                 case Opt_dmask:
 411                         if (match_octal(&args[0], &option))
 412                                 return 0;
 413                         sbi->s_dmask = option;
 414                         break;
 415                 case Opt_fmask:
 416                         if (match_octal(&args[0], &option))
 417                                 return 0;
 418                         sbi->s_fmask = option;
 419                         break;
 420                 default:
 421                         return 0;
 422                 }
 423         }
 424         return 1;
 425 }
 426
 427 static int omfs_fill_super(struct super_block *sb, void *data, int silent)
 428 {
 429         struct buffer_head *bh, *bh2;
 430         struct omfs_super_block *omfs_sb;
 431         struct omfs_root_block *omfs_rb;
 432         struct omfs_sb_info *sbi;
 433         struct inode *root;
 434         int ret = -EINVAL;
 435
 436         save_mount_options(sb, (char *) data);
 437
 438         sbi = kzalloc(sizeof(struct omfs_sb_info), GFP_KERNEL);
 439         if (!sbi)
 440                 return -ENOMEM;
 441
 442         sb->s_fs_info = sbi;
 443
 444         sbi->s_uid = current_uid();
 445         sbi->s_gid = current_gid();
 446         sbi->s_dmask = sbi->s_fmask = current_umask();
 447
 448         if (!parse_options((char *) data, sbi))
 449                 goto end;
 450
 451         sb->s_maxbytes = 0xffffffff;
 452
 453         sb_set_blocksize(sb, 0x200);
 454
 455         bh = sb_bread(sb, 0);
 456         if (!bh)
 457                 goto end;
 458
 459         omfs_sb = (struct omfs_super_block *)bh->b_data;
 460
 461         if (omfs_sb->s_magic != cpu_to_be32(OMFS_MAGIC)) {
 462                 if (!silent)
 463                         printk(KERN_ERR "omfs: Invalid superblock (%x)\n",
 464                                    omfs_sb->s_magic);
 465                 goto out_brelse_bh;
 466         }
 467         sb->s_magic = OMFS_MAGIC;
 468
 469         sbi->s_num_blocks = be64_to_cpu(omfs_sb->s_num_blocks);
 470         sbi->s_blocksize = be32_to_cpu(omfs_sb->s_blocksize);
 471         sbi->s_mirrors = be32_to_cpu(omfs_sb->s_mirrors);
 472         sbi->s_root_ino = be64_to_cpu(omfs_sb->s_root_block);
 473         sbi->s_sys_blocksize = be32_to_cpu(omfs_sb->s_sys_blocksize);
 474         mutex_init(&sbi->s_bitmap_lock);
 475
 476         if (sbi->s_num_blocks > OMFS_MAX_BLOCKS) {
 477                 printk(KERN_ERR "omfs: sysblock number (%llx) is out of range\n",
 478                        (unsigned long long)sbi->s_num_blocks);
 479                 goto out_brelse_bh;
 480         }
 481
 482         if (sbi->s_sys_blocksize > PAGE_SIZE) {
 483                 printk(KERN_ERR "omfs: sysblock size (%d) is out of range\n",
 484                         sbi->s_sys_blocksize);
 485                 goto out_brelse_bh;
 486         }
 487
 488         if (sbi->s_blocksize < sbi->s_sys_blocksize ||
 489             sbi->s_blocksize > OMFS_MAX_BLOCK_SIZE) {
 490                 printk(KERN_ERR "omfs: block size (%d) is out of range\n",
 491                         sbi->s_blocksize);
 492                 goto out_brelse_bh;
 493         }
 494
 495         /*
 496          * Use sys_blocksize as the fs block since it is smaller than a
 497          * page while the fs blocksize can be larger.
 498          */
 499         sb_set_blocksize(sb, sbi->s_sys_blocksize);
 500
 501         /*
 502          * ...and the difference goes into a shift.  sys_blocksize is always
 503          * a power of two factor of blocksize.
 504          */
 505         sbi->s_block_shift = get_bitmask_order(sbi->s_blocksize) -
 506                 get_bitmask_order(sbi->s_sys_blocksize);
 507
 508         bh2 = omfs_bread(sb, be64_to_cpu(omfs_sb->s_root_block));
 509         if (!bh2)
 510                 goto out_brelse_bh;
 511
 512         omfs_rb = (struct omfs_root_block *)bh2->b_data;
 513
 514         sbi->s_bitmap_ino = be64_to_cpu(omfs_rb->r_bitmap);
 515         sbi->s_clustersize = be32_to_cpu(omfs_rb->r_clustersize);
 516
 517         if (sbi->s_num_blocks != be64_to_cpu(omfs_rb->r_num_blocks)) {
 518                 printk(KERN_ERR "omfs: block count discrepancy between "
 519                         "super and root blocks (%llx, %llx)\n",
 520                         (unsigned long long)sbi->s_num_blocks,
 521                         (unsigned long long)be64_to_cpu(omfs_rb->r_num_blocks));
 522                 goto out_brelse_bh2;
 523         }
 524
 525         if (sbi->s_bitmap_ino != ~0ULL &&
 526             sbi->s_bitmap_ino > sbi->s_num_blocks) {
 527                 printk(KERN_ERR "omfs: free space bitmap location is corrupt "
 528                         "(%llx, total blocks %llx)\n",
 529                         (unsigned long long) sbi->s_bitmap_ino,
 530                         (unsigned long long) sbi->s_num_blocks);
 531                 goto out_brelse_bh2;
 532         }
 533         if (sbi->s_clustersize < 1 ||
 534             sbi->s_clustersize > OMFS_MAX_CLUSTER_SIZE) {
 535                 printk(KERN_ERR "omfs: cluster size out of range (%d)",
 536                         sbi->s_clustersize);
 537                 goto out_brelse_bh2;
 538         }
 539
 540         ret = omfs_get_imap(sb);
 541         if (ret)
 542                 goto out_brelse_bh2;
 543
 544         sb->s_op = &omfs_sops;
 545
 546         root = omfs_iget(sb, be64_to_cpu(omfs_rb->r_root_dir));
 547         if (IS_ERR(root)) {
 548                 ret = PTR_ERR(root);
 549                 goto out_brelse_bh2;
 550         }
 551
 552         sb->s_root = d_make_root(root);
 553         if (!sb->s_root) {
 554                 ret = -ENOMEM;
 555                 goto out_brelse_bh2;
 556         }
 557         printk(KERN_DEBUG "omfs: Mounted volume %s\n", omfs_rb->r_name);
 558
 559         ret = 0;
 560 out_brelse_bh2:
 561         brelse(bh2);
 562 out_brelse_bh:
 563         brelse(bh);
 564 end:
 565         if (ret)
 566                 kfree(sbi);
 567         return ret;
 568 }
 569
 570 static struct dentry *omfs_mount(struct file_system_type *fs_type,
 571                         int flags, const char *dev_name, void *data)
 572 {
 573         return mount_bdev(fs_type, flags, dev_name, data, omfs_fill_super);
 574 }
 575
 576 static struct file_system_type omfs_fs_type = {
 577         .owner = THIS_MODULE,
 578         .name = "omfs",
 579         .mount = omfs_mount,
 580         .kill_sb = kill_block_super,
 581         .fs_flags = FS_REQUIRES_DEV,
 582 };
 583 MODULE_ALIAS_FS("omfs");
 584
 585 static int __init init_omfs_fs(void)
 586 {
 587         return register_filesystem(&omfs_fs_type);
 588 }
 589
 590 static void __exit exit_omfs_fs(void)
 591 {
 592         unregister_filesystem(&omfs_fs_type);
 593 }
 594
 595 module_init(init_omfs_fs);
 596 module_exit(exit_omfs_fs);