fs/omfs/inode.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Optimized MPEG FS - inode and super operations.
   4  * Copyright (C) 2006 Bob Copeland <me@bobcopeland.com>
   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/cred.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/seq_file.h>
  17 #include <linux/crc-itu-t.h>
  18 #include "omfs.h"
  19
  20 MODULE_AUTHOR("Bob Copeland <me@bobcopeland.com>");
  21 MODULE_DESCRIPTION("OMFS (ReplayTV/Karma) Filesystem for Linux");
  22 MODULE_LICENSE("GPL");
  23
  24 struct buffer_head *omfs_bread(struct super_block *sb, sector_t block)
  25 {
  26         struct omfs_sb_info *sbi = OMFS_SB(sb);
  27         if (block >= sbi->s_num_blocks)
  28                 return NULL;
  29
  30         return sb_bread(sb, clus_to_blk(sbi, block));
  31 }
  32
  33 struct inode *omfs_new_inode(struct inode *dir, umode_t mode)
  34 {
  35         struct inode *inode;
  36         u64 new_block;
  37         int err;
  38         int len;
  39         struct omfs_sb_info *sbi = OMFS_SB(dir->i_sb);
  40
  41         inode = new_inode(dir->i_sb);
  42         if (!inode)
  43                 return ERR_PTR(-ENOMEM);
  44
  45         err = omfs_allocate_range(dir->i_sb, sbi->s_mirrors, sbi->s_mirrors,
  46                         &new_block, &len);
  47         if (err)
  48                 goto fail;
  49
  50         inode->i_ino = new_block;
  51         inode_init_owner(&nop_mnt_idmap, inode, NULL, mode);
  52         inode->i_mapping->a_ops = &omfs_aops;
  53
  54         simple_inode_init_ts(inode);
  55         switch (mode & S_IFMT) {
  56         case S_IFDIR:
  57                 inode->i_op = &omfs_dir_inops;
  58                 inode->i_fop = &omfs_dir_operations;
  59                 inode->i_size = sbi->s_sys_blocksize;
  60                 inc_nlink(inode);
  61                 break;
  62         case S_IFREG:
  63                 inode->i_op = &omfs_file_inops;
  64                 inode->i_fop = &omfs_file_operations;
  65                 inode->i_size = 0;
  66                 break;
  67         }
  68
  69         insert_inode_hash(inode);
  70         mark_inode_dirty(inode);
  71         return inode;
  72 fail:
  73         make_bad_inode(inode);
  74         iput(inode);
  75         return ERR_PTR(err);
  76 }
  77
  78 /*
  79  * Update the header checksums for a dirty inode based on its contents.
  80  * Caller is expected to hold the buffer head underlying oi and mark it
  81  * dirty.
  82  */
  83 static void omfs_update_checksums(struct omfs_inode *oi)
  84 {
  85         int xor, i, ofs = 0, count;
  86         u16 crc = 0;
  87         unsigned char *ptr = (unsigned char *) oi;
  88
  89         count = be32_to_cpu(oi->i_head.h_body_size);
  90         ofs = sizeof(struct omfs_header);
  91
  92         crc = crc_itu_t(crc, ptr + ofs, count);
  93         oi->i_head.h_crc = cpu_to_be16(crc);
  94
  95         xor = ptr[0];
  96         for (i = 1; i < OMFS_XOR_COUNT; i++)
  97                 xor ^= ptr[i];
  98
  99         oi->i_head.h_check_xor = xor;
 100 }
 101
 102 static int __omfs_write_inode(struct inode *inode, int wait)
 103 {
 104         struct omfs_inode *oi;
 105         struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
 106         struct buffer_head *bh, *bh2;
 107         u64 ctime;
 108         int i;
 109         int ret = -EIO;
 110         int sync_failed = 0;
 111
 112         /* get current inode since we may have written sibling ptrs etc. */
 113         bh = omfs_bread(inode->i_sb, inode->i_ino);
 114         if (!bh)
 115                 goto out;
 116
 117         oi = (struct omfs_inode *) bh->b_data;
 118
 119         oi->i_head.h_self = cpu_to_be64(inode->i_ino);
 120         if (S_ISDIR(inode->i_mode))
 121                 oi->i_type = OMFS_DIR;
 122         else if (S_ISREG(inode->i_mode))
 123                 oi->i_type = OMFS_FILE;
 124         else {
 125                 printk(KERN_WARNING "omfs: unknown file type: %d\n",
 126                         inode->i_mode);
 127                 goto out_brelse;
 128         }
 129
 130         oi->i_head.h_body_size = cpu_to_be32(sbi->s_sys_blocksize -
 131                 sizeof(struct omfs_header));
 132         oi->i_head.h_version = 1;
 133         oi->i_head.h_type = OMFS_INODE_NORMAL;
 134         oi->i_head.h_magic = OMFS_IMAGIC;
 135         oi->i_size = cpu_to_be64(inode->i_size);
 136
 137         ctime = inode_get_ctime_sec(inode) * 1000LL +
 138                 ((inode_get_ctime_nsec(inode) + 999)/1000);
 139         oi->i_ctime = cpu_to_be64(ctime);
 140
 141         omfs_update_checksums(oi);
 142
 143         mark_buffer_dirty(bh);
 144         if (wait) {
 145                 sync_dirty_buffer(bh);
 146                 if (buffer_req(bh) && !buffer_uptodate(bh))
 147                         sync_failed = 1;
 148         }
 149
 150         /* if mirroring writes, copy to next fsblock */
 151         for (i = 1; i < sbi->s_mirrors; i++) {
 152                 bh2 = omfs_bread(inode->i_sb, inode->i_ino + i);
 153                 if (!bh2)
 154                         goto out_brelse;
 155
 156                 memcpy(bh2->b_data, bh->b_data, bh->b_size);
 157                 mark_buffer_dirty(bh2);
 158                 if (wait) {
 159                         sync_dirty_buffer(bh2);
 160                         if (buffer_req(bh2) && !buffer_uptodate(bh2))
 161                                 sync_failed = 1;
 162                 }
 163                 brelse(bh2);
 164         }
 165         ret = (sync_failed) ? -EIO : 0;
 166 out_brelse:
 167         brelse(bh);
 168 out:
 169         return ret;
 170 }
 171
 172 static int omfs_write_inode(struct inode *inode, struct writeback_control *wbc)
 173 {
 174         return __omfs_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
 175 }
 176
 177 int omfs_sync_inode(struct inode *inode)
 178 {
 179         return __omfs_write_inode(inode, 1);
 180 }
 181
 182 /*
 183  * called when an entry is deleted, need to clear the bits in the
 184  * bitmaps.
 185  */
 186 static void omfs_evict_inode(struct inode *inode)
 187 {
 188         truncate_inode_pages_final(&inode->i_data);
 189         clear_inode(inode);
 190
 191         if (inode->i_nlink)
 192                 return;
 193
 194         if (S_ISREG(inode->i_mode)) {
 195                 inode->i_size = 0;
 196                 omfs_shrink_inode(inode);
 197         }
 198
 199         omfs_clear_range(inode->i_sb, inode->i_ino, 2);
 200 }
 201
 202 struct inode *omfs_iget(struct super_block *sb, ino_t ino)
 203 {
 204         struct omfs_sb_info *sbi = OMFS_SB(sb);
 205         struct omfs_inode *oi;
 206         struct buffer_head *bh;
 207         u64 ctime;
 208         unsigned long nsecs;
 209         struct inode *inode;
 210
 211         inode = iget_locked(sb, ino);
 212         if (!inode)
 213                 return ERR_PTR(-ENOMEM);
 214         if (!(inode->i_state & I_NEW))
 215                 return inode;
 216
 217         bh = omfs_bread(inode->i_sb, ino);
 218         if (!bh)
 219                 goto iget_failed;
 220
 221         oi = (struct omfs_inode *)bh->b_data;
 222
 223         /* check self */
 224         if (ino != be64_to_cpu(oi->i_head.h_self))
 225                 goto fail_bh;
 226
 227         inode->i_uid = sbi->s_uid;
 228         inode->i_gid = sbi->s_gid;
 229
 230         ctime = be64_to_cpu(oi->i_ctime);
 231         nsecs = do_div(ctime, 1000) * 1000L;
 232
 233         inode_set_atime(inode, ctime, nsecs);
 234         inode_set_mtime(inode, ctime, nsecs);
 235         inode_set_ctime(inode, ctime, nsecs);
 236
 237         inode->i_mapping->a_ops = &omfs_aops;
 238
 239         switch (oi->i_type) {
 240         case OMFS_DIR:
 241                 inode->i_mode = S_IFDIR | (S_IRWXUGO & ~sbi->s_dmask);
 242                 inode->i_op = &omfs_dir_inops;
 243                 inode->i_fop = &omfs_dir_operations;
 244                 inode->i_size = sbi->s_sys_blocksize;
 245                 inc_nlink(inode);
 246                 break;
 247         case OMFS_FILE:
 248                 inode->i_mode = S_IFREG | (S_IRWXUGO & ~sbi->s_fmask);
 249                 inode->i_fop = &omfs_file_operations;
 250                 inode->i_size = be64_to_cpu(oi->i_size);
 251                 break;
 252         }
 253         brelse(bh);
 254         unlock_new_inode(inode);
 255         return inode;
 256 fail_bh:
 257         brelse(bh);
 258 iget_failed:
 259         iget_failed(inode);
 260         return ERR_PTR(-EIO);
 261 }
 262
 263 static void omfs_put_super(struct super_block *sb)
 264 {
 265         struct omfs_sb_info *sbi = OMFS_SB(sb);
 266         kfree(sbi->s_imap);
 267         kfree(sbi);
 268         sb->s_fs_info = NULL;
 269 }
 270
 271 static int omfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 272 {
 273         struct super_block *s = dentry->d_sb;
 274         struct omfs_sb_info *sbi = OMFS_SB(s);
 275         u64 id = huge_encode_dev(s->s_bdev->bd_dev);
 276
 277         buf->f_type = OMFS_MAGIC;
 278         buf->f_bsize = sbi->s_blocksize;
 279         buf->f_blocks = sbi->s_num_blocks;
 280         buf->f_files = sbi->s_num_blocks;
 281         buf->f_namelen = OMFS_NAMELEN;
 282         buf->f_fsid = u64_to_fsid(id);
 283
 284         buf->f_bfree = buf->f_bavail = buf->f_ffree =
 285                 omfs_count_free(s);
 286
 287         return 0;
 288 }
 289
 290 /*
 291  * Display the mount options in /proc/mounts.
 292  */
 293 static int omfs_show_options(struct seq_file *m, struct dentry *root)
 294 {
 295         struct omfs_sb_info *sbi = OMFS_SB(root->d_sb);
 296         umode_t cur_umask = current_umask();
 297
 298         if (!uid_eq(sbi->s_uid, current_uid()))
 299                 seq_printf(m, ",uid=%u",
 300                            from_kuid_munged(&init_user_ns, sbi->s_uid));
 301         if (!gid_eq(sbi->s_gid, current_gid()))
 302                 seq_printf(m, ",gid=%u",
 303                            from_kgid_munged(&init_user_ns, sbi->s_gid));
 304
 305         if (sbi->s_dmask == sbi->s_fmask) {
 306                 if (sbi->s_fmask != cur_umask)
 307                         seq_printf(m, ",umask=%o", sbi->s_fmask);
 308         } else {
 309                 if (sbi->s_dmask != cur_umask)
 310                         seq_printf(m, ",dmask=%o", sbi->s_dmask);
 311                 if (sbi->s_fmask != cur_umask)
 312                         seq_printf(m, ",fmask=%o", sbi->s_fmask);
 313         }
 314
 315         return 0;
 316 }
 317
 318 static const struct super_operations omfs_sops = {
 319         .write_inode    = omfs_write_inode,
 320         .evict_inode    = omfs_evict_inode,
 321         .put_super      = omfs_put_super,
 322         .statfs         = omfs_statfs,
 323         .show_options   = omfs_show_options,
 324 };
 325
 326 /*
 327  * For Rio Karma, there is an on-disk free bitmap whose location is
 328  * stored in the root block.  For ReplayTV, there is no such free bitmap
 329  * so we have to walk the tree.  Both inodes and file data are allocated
 330  * from the same map.  This array can be big (300k) so we allocate
 331  * in units of the blocksize.
 332  */
 333 static int omfs_get_imap(struct super_block *sb)
 334 {
 335         unsigned int bitmap_size, array_size;
 336         int count;
 337         struct omfs_sb_info *sbi = OMFS_SB(sb);
 338         struct buffer_head *bh;
 339         unsigned long **ptr;
 340         sector_t block;
 341
 342         bitmap_size = DIV_ROUND_UP(sbi->s_num_blocks, 8);
 343         array_size = DIV_ROUND_UP(bitmap_size, sb->s_blocksize);
 344
 345         if (sbi->s_bitmap_ino == ~0ULL)
 346                 goto out;
 347
 348         sbi->s_imap_size = array_size;
 349         sbi->s_imap = kcalloc(array_size, sizeof(unsigned long *), GFP_KERNEL);
 350         if (!sbi->s_imap)
 351                 goto nomem;
 352
 353         block = clus_to_blk(sbi, sbi->s_bitmap_ino);
 354         if (block >= sbi->s_num_blocks)
 355                 goto nomem;
 356
 357         ptr = sbi->s_imap;
 358         for (count = bitmap_size; count > 0; count -= sb->s_blocksize) {
 359                 bh = sb_bread(sb, block++);
 360                 if (!bh)
 361                         goto nomem_free;
 362                 *ptr = kmemdup(bh->b_data, sb->s_blocksize, GFP_KERNEL);
 363                 if (!*ptr) {
 364                         brelse(bh);
 365                         goto nomem_free;
 366                 }
 367                 if (count < sb->s_blocksize)
 368                         memset((void *)*ptr + count, 0xff,
 369                                 sb->s_blocksize - count);
 370                 brelse(bh);
 371                 ptr++;
 372         }
 373 out:
 374         return 0;
 375
 376 nomem_free:
 377         for (count = 0; count < array_size; count++)
 378                 kfree(sbi->s_imap[count]);
 379
 380         kfree(sbi->s_imap);
 381 nomem:
 382         sbi->s_imap = NULL;
 383         sbi->s_imap_size = 0;
 384         return -ENOMEM;
 385 }
 386
 387 enum {
 388         Opt_uid, Opt_gid, Opt_umask, Opt_dmask, Opt_fmask, Opt_err
 389 };
 390
 391 static const match_table_t tokens = {
 392         {Opt_uid, "uid=%u"},
 393         {Opt_gid, "gid=%u"},
 394         {Opt_umask, "umask=%o"},
 395         {Opt_dmask, "dmask=%o"},
 396         {Opt_fmask, "fmask=%o"},
 397         {Opt_err, NULL},
 398 };
 399
 400 static int parse_options(char *options, struct omfs_sb_info *sbi)
 401 {
 402         char *p;
 403         substring_t args[MAX_OPT_ARGS];
 404         int option;
 405
 406         if (!options)
 407                 return 1;
 408
 409         while ((p = strsep(&options, ",")) != NULL) {
 410                 int token;
 411                 if (!*p)
 412                         continue;
 413
 414                 token = match_token(p, tokens, args);
 415                 switch (token) {
 416                 case Opt_uid:
 417                         if (match_int(&args[0], &option))
 418                                 return 0;
 419                         sbi->s_uid = make_kuid(current_user_ns(), option);
 420                         if (!uid_valid(sbi->s_uid))
 421                                 return 0;
 422                         break;
 423                 case Opt_gid:
 424                         if (match_int(&args[0], &option))
 425                                 return 0;
 426                         sbi->s_gid = make_kgid(current_user_ns(), option);
 427                         if (!gid_valid(sbi->s_gid))
 428                                 return 0;
 429                         break;
 430                 case Opt_umask:
 431                         if (match_octal(&args[0], &option))
 432                                 return 0;
 433                         sbi->s_fmask = sbi->s_dmask = option;
 434                         break;
 435                 case Opt_dmask:
 436                         if (match_octal(&args[0], &option))
 437                                 return 0;
 438                         sbi->s_dmask = option;
 439                         break;
 440                 case Opt_fmask:
 441                         if (match_octal(&args[0], &option))
 442                                 return 0;
 443                         sbi->s_fmask = option;
 444                         break;
 445                 default:
 446                         return 0;
 447                 }
 448         }
 449         return 1;
 450 }
 451
 452 static int omfs_fill_super(struct super_block *sb, void *data, int silent)
 453 {
 454         struct buffer_head *bh, *bh2;
 455         struct omfs_super_block *omfs_sb;
 456         struct omfs_root_block *omfs_rb;
 457         struct omfs_sb_info *sbi;
 458         struct inode *root;
 459         int ret = -EINVAL;
 460
 461         sbi = kzalloc(sizeof(struct omfs_sb_info), GFP_KERNEL);
 462         if (!sbi)
 463                 return -ENOMEM;
 464
 465         sb->s_fs_info = sbi;
 466
 467         sbi->s_uid = current_uid();
 468         sbi->s_gid = current_gid();
 469         sbi->s_dmask = sbi->s_fmask = current_umask();
 470
 471         if (!parse_options((char *) data, sbi))
 472                 goto end;
 473
 474         sb->s_maxbytes = 0xffffffff;
 475
 476         sb->s_time_gran = NSEC_PER_MSEC;
 477         sb->s_time_min = 0;
 478         sb->s_time_max = U64_MAX / MSEC_PER_SEC;
 479
 480         sb_set_blocksize(sb, 0x200);
 481
 482         bh = sb_bread(sb, 0);
 483         if (!bh)
 484                 goto end;
 485
 486         omfs_sb = (struct omfs_super_block *)bh->b_data;
 487
 488         if (omfs_sb->s_magic != cpu_to_be32(OMFS_MAGIC)) {
 489                 if (!silent)
 490                         printk(KERN_ERR "omfs: Invalid superblock (%x)\n",
 491                                    omfs_sb->s_magic);
 492                 goto out_brelse_bh;
 493         }
 494         sb->s_magic = OMFS_MAGIC;
 495
 496         sbi->s_num_blocks = be64_to_cpu(omfs_sb->s_num_blocks);
 497         sbi->s_blocksize = be32_to_cpu(omfs_sb->s_blocksize);
 498         sbi->s_mirrors = be32_to_cpu(omfs_sb->s_mirrors);
 499         sbi->s_root_ino = be64_to_cpu(omfs_sb->s_root_block);
 500         sbi->s_sys_blocksize = be32_to_cpu(omfs_sb->s_sys_blocksize);
 501         mutex_init(&sbi->s_bitmap_lock);
 502
 503         if (sbi->s_num_blocks > OMFS_MAX_BLOCKS) {
 504                 printk(KERN_ERR "omfs: sysblock number (%llx) is out of range\n",
 505                        (unsigned long long)sbi->s_num_blocks);
 506                 goto out_brelse_bh;
 507         }
 508
 509         if (sbi->s_sys_blocksize > PAGE_SIZE) {
 510                 printk(KERN_ERR "omfs: sysblock size (%d) is out of range\n",
 511                         sbi->s_sys_blocksize);
 512                 goto out_brelse_bh;
 513         }
 514
 515         if (sbi->s_blocksize < sbi->s_sys_blocksize ||
 516             sbi->s_blocksize > OMFS_MAX_BLOCK_SIZE) {
 517                 printk(KERN_ERR "omfs: block size (%d) is out of range\n",
 518                         sbi->s_blocksize);
 519                 goto out_brelse_bh;
 520         }
 521
 522         /*
 523          * Use sys_blocksize as the fs block since it is smaller than a
 524          * page while the fs blocksize can be larger.
 525          */
 526         sb_set_blocksize(sb, sbi->s_sys_blocksize);
 527
 528         /*
 529          * ...and the difference goes into a shift.  sys_blocksize is always
 530          * a power of two factor of blocksize.
 531          */
 532         sbi->s_block_shift = get_bitmask_order(sbi->s_blocksize) -
 533                 get_bitmask_order(sbi->s_sys_blocksize);
 534
 535         bh2 = omfs_bread(sb, be64_to_cpu(omfs_sb->s_root_block));
 536         if (!bh2)
 537                 goto out_brelse_bh;
 538
 539         omfs_rb = (struct omfs_root_block *)bh2->b_data;
 540
 541         sbi->s_bitmap_ino = be64_to_cpu(omfs_rb->r_bitmap);
 542         sbi->s_clustersize = be32_to_cpu(omfs_rb->r_clustersize);
 543
 544         if (sbi->s_num_blocks != be64_to_cpu(omfs_rb->r_num_blocks)) {
 545                 printk(KERN_ERR "omfs: block count discrepancy between "
 546                         "super and root blocks (%llx, %llx)\n",
 547                         (unsigned long long)sbi->s_num_blocks,
 548                         (unsigned long long)be64_to_cpu(omfs_rb->r_num_blocks));
 549                 goto out_brelse_bh2;
 550         }
 551
 552         if (sbi->s_bitmap_ino != ~0ULL &&
 553             sbi->s_bitmap_ino > sbi->s_num_blocks) {
 554                 printk(KERN_ERR "omfs: free space bitmap location is corrupt "
 555                         "(%llx, total blocks %llx)\n",
 556                         (unsigned long long) sbi->s_bitmap_ino,
 557                         (unsigned long long) sbi->s_num_blocks);
 558                 goto out_brelse_bh2;
 559         }
 560         if (sbi->s_clustersize < 1 ||
 561             sbi->s_clustersize > OMFS_MAX_CLUSTER_SIZE) {
 562                 printk(KERN_ERR "omfs: cluster size out of range (%d)",
 563                         sbi->s_clustersize);
 564                 goto out_brelse_bh2;
 565         }
 566
 567         ret = omfs_get_imap(sb);
 568         if (ret)
 569                 goto out_brelse_bh2;
 570
 571         sb->s_op = &omfs_sops;
 572
 573         root = omfs_iget(sb, be64_to_cpu(omfs_rb->r_root_dir));
 574         if (IS_ERR(root)) {
 575                 ret = PTR_ERR(root);
 576                 goto out_brelse_bh2;
 577         }
 578
 579         sb->s_root = d_make_root(root);
 580         if (!sb->s_root) {
 581                 ret = -ENOMEM;
 582                 goto out_brelse_bh2;
 583         }
 584         printk(KERN_DEBUG "omfs: Mounted volume %s\n", omfs_rb->r_name);
 585
 586         ret = 0;
 587 out_brelse_bh2:
 588         brelse(bh2);
 589 out_brelse_bh:
 590         brelse(bh);
 591 end:
 592         if (ret)
 593                 kfree(sbi);
 594         return ret;
 595 }
 596
 597 static struct dentry *omfs_mount(struct file_system_type *fs_type,
 598                         int flags, const char *dev_name, void *data)
 599 {
 600         return mount_bdev(fs_type, flags, dev_name, data, omfs_fill_super);
 601 }
 602
 603 static struct file_system_type omfs_fs_type = {
 604         .owner = THIS_MODULE,
 605         .name = "omfs",
 606         .mount = omfs_mount,
 607         .kill_sb = kill_block_super,
 608         .fs_flags = FS_REQUIRES_DEV,
 609 };
 610 MODULE_ALIAS_FS("omfs");
 611
 612 static int __init init_omfs_fs(void)
 613 {
 614         return register_filesystem(&omfs_fs_type);
 615 }
 616
 617 static void __exit exit_omfs_fs(void)
 618 {
 619         unregister_filesystem(&omfs_fs_type);
 620 }
 621
 622 module_init(init_omfs_fs);
 623 module_exit(exit_omfs_fs);