linux/fs/omfs/inode.c
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   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
  18MODULE_AUTHOR("Bob Copeland <me@bobcopeland.com>");
  19MODULE_DESCRIPTION("OMFS (ReplayTV/Karma) Filesystem for Linux");
  20MODULE_LICENSE("GPL");
  21
  22struct 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
  31struct 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;
  70fail:
  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 */
  81static 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
 100static 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;
 164out_brelse:
 165        brelse(bh);
 166out:
 167        return ret;
 168}
 169
 170static 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
 175int 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 */
 184static void omfs_evict_inode(struct inode *inode)
 185{
 186        truncate_inode_pages(&inode->i_data, 0);
 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
 200struct 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;
 257fail_bh:
 258        brelse(bh);
 259iget_failed:
 260        iget_failed(inode);
 261        return ERR_PTR(-EIO);
 262}
 263
 264static 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
 272static 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
 292static 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 */
 307static int omfs_get_imap(struct super_block *sb)
 308{
 309        int bitmap_size;
 310        int array_size;
 311        int count;
 312        struct omfs_sb_info *sbi = OMFS_SB(sb);
 313        struct buffer_head *bh;
 314        unsigned long **ptr;
 315        sector_t block;
 316
 317        bitmap_size = DIV_ROUND_UP(sbi->s_num_blocks, 8);
 318        array_size = DIV_ROUND_UP(bitmap_size, sb->s_blocksize);
 319
 320        if (sbi->s_bitmap_ino == ~0ULL)
 321                goto out;
 322
 323        sbi->s_imap_size = array_size;
 324        sbi->s_imap = kzalloc(array_size * sizeof(unsigned long *), GFP_KERNEL);
 325        if (!sbi->s_imap)
 326                goto nomem;
 327
 328        block = clus_to_blk(sbi, sbi->s_bitmap_ino);
 329        if (block >= sbi->s_num_blocks)
 330                goto nomem;
 331
 332        ptr = sbi->s_imap;
 333        for (count = bitmap_size; count > 0; count -= sb->s_blocksize) {
 334                bh = sb_bread(sb, block++);
 335                if (!bh)
 336                        goto nomem_free;
 337                *ptr = kmalloc(sb->s_blocksize, GFP_KERNEL);
 338                if (!*ptr) {
 339                        brelse(bh);
 340                        goto nomem_free;
 341                }
 342                memcpy(*ptr, bh->b_data, sb->s_blocksize);
 343                if (count < sb->s_blocksize)
 344                        memset((void *)*ptr + count, 0xff,
 345                                sb->s_blocksize - count);
 346                brelse(bh);
 347                ptr++;
 348        }
 349out:
 350        return 0;
 351
 352nomem_free:
 353        for (count = 0; count < array_size; count++)
 354                kfree(sbi->s_imap[count]);
 355
 356        kfree(sbi->s_imap);
 357nomem:
 358        sbi->s_imap = NULL;
 359        sbi->s_imap_size = 0;
 360        return -ENOMEM;
 361}
 362
 363enum {
 364        Opt_uid, Opt_gid, Opt_umask, Opt_dmask, Opt_fmask
 365};
 366
 367static const match_table_t tokens = {
 368        {Opt_uid, "uid=%u"},
 369        {Opt_gid, "gid=%u"},
 370        {Opt_umask, "umask=%o"},
 371        {Opt_dmask, "dmask=%o"},
 372        {Opt_fmask, "fmask=%o"},
 373};
 374
 375static 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 = option;
 395                        break;
 396                case Opt_gid:
 397                        if (match_int(&args[0], &option))
 398                                return 0;
 399                        sbi->s_gid = option;
 400                        break;
 401                case Opt_umask:
 402                        if (match_octal(&args[0], &option))
 403                                return 0;
 404                        sbi->s_fmask = sbi->s_dmask = option;
 405                        break;
 406                case Opt_dmask:
 407                        if (match_octal(&args[0], &option))
 408                                return 0;
 409                        sbi->s_dmask = option;
 410                        break;
 411                case Opt_fmask:
 412                        if (match_octal(&args[0], &option))
 413                                return 0;
 414                        sbi->s_fmask = option;
 415                        break;
 416                default:
 417                        return 0;
 418                }
 419        }
 420        return 1;
 421}
 422
 423static int omfs_fill_super(struct super_block *sb, void *data, int silent)
 424{
 425        struct buffer_head *bh, *bh2;
 426        struct omfs_super_block *omfs_sb;
 427        struct omfs_root_block *omfs_rb;
 428        struct omfs_sb_info *sbi;
 429        struct inode *root;
 430        int ret = -EINVAL;
 431
 432        save_mount_options(sb, (char *) data);
 433
 434        sbi = kzalloc(sizeof(struct omfs_sb_info), GFP_KERNEL);
 435        if (!sbi)
 436                return -ENOMEM;
 437
 438        sb->s_fs_info = sbi;
 439
 440        sbi->s_uid = current_uid();
 441        sbi->s_gid = current_gid();
 442        sbi->s_dmask = sbi->s_fmask = current_umask();
 443
 444        if (!parse_options((char *) data, sbi))
 445                goto end;
 446
 447        sb->s_maxbytes = 0xffffffff;
 448
 449        sb_set_blocksize(sb, 0x200);
 450
 451        bh = sb_bread(sb, 0);
 452        if (!bh)
 453                goto end;
 454
 455        omfs_sb = (struct omfs_super_block *)bh->b_data;
 456
 457        if (omfs_sb->s_magic != cpu_to_be32(OMFS_MAGIC)) {
 458                if (!silent)
 459                        printk(KERN_ERR "omfs: Invalid superblock (%x)\n",
 460                                   omfs_sb->s_magic);
 461                goto out_brelse_bh;
 462        }
 463        sb->s_magic = OMFS_MAGIC;
 464
 465        sbi->s_num_blocks = be64_to_cpu(omfs_sb->s_num_blocks);
 466        sbi->s_blocksize = be32_to_cpu(omfs_sb->s_blocksize);
 467        sbi->s_mirrors = be32_to_cpu(omfs_sb->s_mirrors);
 468        sbi->s_root_ino = be64_to_cpu(omfs_sb->s_root_block);
 469        sbi->s_sys_blocksize = be32_to_cpu(omfs_sb->s_sys_blocksize);
 470        mutex_init(&sbi->s_bitmap_lock);
 471
 472        if (sbi->s_sys_blocksize > PAGE_SIZE) {
 473                printk(KERN_ERR "omfs: sysblock size (%d) is out of range\n",
 474                        sbi->s_sys_blocksize);
 475                goto out_brelse_bh;
 476        }
 477
 478        if (sbi->s_blocksize < sbi->s_sys_blocksize ||
 479            sbi->s_blocksize > OMFS_MAX_BLOCK_SIZE) {
 480                printk(KERN_ERR "omfs: block size (%d) is out of range\n",
 481                        sbi->s_blocksize);
 482                goto out_brelse_bh;
 483        }
 484
 485        /*
 486         * Use sys_blocksize as the fs block since it is smaller than a
 487         * page while the fs blocksize can be larger.
 488         */
 489        sb_set_blocksize(sb, sbi->s_sys_blocksize);
 490
 491        /*
 492         * ...and the difference goes into a shift.  sys_blocksize is always
 493         * a power of two factor of blocksize.
 494         */
 495        sbi->s_block_shift = get_bitmask_order(sbi->s_blocksize) -
 496                get_bitmask_order(sbi->s_sys_blocksize);
 497
 498        bh2 = omfs_bread(sb, be64_to_cpu(omfs_sb->s_root_block));
 499        if (!bh2)
 500                goto out_brelse_bh;
 501
 502        omfs_rb = (struct omfs_root_block *)bh2->b_data;
 503
 504        sbi->s_bitmap_ino = be64_to_cpu(omfs_rb->r_bitmap);
 505        sbi->s_clustersize = be32_to_cpu(omfs_rb->r_clustersize);
 506
 507        if (sbi->s_num_blocks != be64_to_cpu(omfs_rb->r_num_blocks)) {
 508                printk(KERN_ERR "omfs: block count discrepancy between "
 509                        "super and root blocks (%llx, %llx)\n",
 510                        (unsigned long long)sbi->s_num_blocks,
 511                        (unsigned long long)be64_to_cpu(omfs_rb->r_num_blocks));
 512                goto out_brelse_bh2;
 513        }
 514
 515        if (sbi->s_bitmap_ino != ~0ULL &&
 516            sbi->s_bitmap_ino > sbi->s_num_blocks) {
 517                printk(KERN_ERR "omfs: free space bitmap location is corrupt "
 518                        "(%llx, total blocks %llx)\n",
 519                        (unsigned long long) sbi->s_bitmap_ino,
 520                        (unsigned long long) sbi->s_num_blocks);
 521                goto out_brelse_bh2;
 522        }
 523        if (sbi->s_clustersize < 1 ||
 524            sbi->s_clustersize > OMFS_MAX_CLUSTER_SIZE) {
 525                printk(KERN_ERR "omfs: cluster size out of range (%d)",
 526                        sbi->s_clustersize);
 527                goto out_brelse_bh2;
 528        }
 529
 530        ret = omfs_get_imap(sb);
 531        if (ret)
 532                goto out_brelse_bh2;
 533
 534        sb->s_op = &omfs_sops;
 535
 536        root = omfs_iget(sb, be64_to_cpu(omfs_rb->r_root_dir));
 537        if (IS_ERR(root)) {
 538                ret = PTR_ERR(root);
 539                goto out_brelse_bh2;
 540        }
 541
 542        sb->s_root = d_make_root(root);
 543        if (!sb->s_root)
 544                goto out_brelse_bh2;
 545        printk(KERN_DEBUG "omfs: Mounted volume %s\n", omfs_rb->r_name);
 546
 547        ret = 0;
 548out_brelse_bh2:
 549        brelse(bh2);
 550out_brelse_bh:
 551        brelse(bh);
 552end:
 553        if (ret)
 554                kfree(sbi);
 555        return ret;
 556}
 557
 558static struct dentry *omfs_mount(struct file_system_type *fs_type,
 559                        int flags, const char *dev_name, void *data)
 560{
 561        return mount_bdev(fs_type, flags, dev_name, data, omfs_fill_super);
 562}
 563
 564static struct file_system_type omfs_fs_type = {
 565        .owner = THIS_MODULE,
 566        .name = "omfs",
 567        .mount = omfs_mount,
 568        .kill_sb = kill_block_super,
 569        .fs_flags = FS_REQUIRES_DEV,
 570};
 571
 572static int __init init_omfs_fs(void)
 573{
 574        return register_filesystem(&omfs_fs_type);
 575}
 576
 577static void __exit exit_omfs_fs(void)
 578{
 579        unregister_filesystem(&omfs_fs_type);
 580}
 581
 582module_init(init_omfs_fs);
 583module_exit(exit_omfs_fs);
 584
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