LXR linux/fs/isofs/rock.c

   1/*
   2 *  linux/fs/isofs/rock.c
   3 *
   4 *  (C) 1992, 1993  Eric Youngdale
   5 *
   6 *  Rock Ridge Extensions to iso9660
   7 */
   8
   9#include <linux/slab.h>
  10#include <linux/pagemap.h>
  11
  12#include "isofs.h"
  13#include "rock.h"
  14
  15/*
  16 * These functions are designed to read the system areas of a directory record
  17 * and extract relevant information.  There are different functions provided
  18 * depending upon what information we need at the time.  One function fills
  19 * out an inode structure, a second one extracts a filename, a third one
  20 * returns a symbolic link name, and a fourth one returns the extent number
  21 * for the file.
  22 */
  23
  24#define SIG(A,B) ((A) | ((B) << 8))     /* isonum_721() */
  25
  26struct rock_state {
  27        void *buffer;
  28        unsigned char *chr;
  29        int len;
  30        int cont_size;
  31        int cont_extent;
  32        int cont_offset;
  33        struct inode *inode;
  34};
  35
  36/*
  37 * This is a way of ensuring that we have something in the system
  38 * use fields that is compatible with Rock Ridge.  Return zero on success.
  39 */
  40
  41static int check_sp(struct rock_ridge *rr, struct inode *inode)
  42{
  43        if (rr->u.SP.magic[0] != 0xbe)
  44                return -1;
  45        if (rr->u.SP.magic[1] != 0xef)
  46                return -1;
  47        ISOFS_SB(inode->i_sb)->s_rock_offset = rr->u.SP.skip;
  48        return 0;
  49}
  50
  51static void setup_rock_ridge(struct iso_directory_record *de,
  52                        struct inode *inode, struct rock_state *rs)
  53{
  54        rs->len = sizeof(struct iso_directory_record) + de->name_len[0];
  55        if (rs->len & 1)
  56                (rs->len)++;
  57        rs->chr = (unsigned char *)de + rs->len;
  58        rs->len = *((unsigned char *)de) - rs->len;
  59        if (rs->len < 0)
  60                rs->len = 0;
  61
  62        if (ISOFS_SB(inode->i_sb)->s_rock_offset != -1) {
  63                rs->len -= ISOFS_SB(inode->i_sb)->s_rock_offset;
  64                rs->chr += ISOFS_SB(inode->i_sb)->s_rock_offset;
  65                if (rs->len < 0)
  66                        rs->len = 0;
  67        }
  68}
  69
  70static void init_rock_state(struct rock_state *rs, struct inode *inode)
  71{
  72        memset(rs, 0, sizeof(*rs));
  73        rs->inode = inode;
  74}
  75
  76/*
  77 * Returns 0 if the caller should continue scanning, 1 if the scan must end
  78 * and -ve on error.
  79 */
  80static int rock_continue(struct rock_state *rs)
  81{
  82        int ret = 1;
  83        int blocksize = 1 << rs->inode->i_blkbits;
  84        const int min_de_size = offsetof(struct rock_ridge, u);
  85
  86        kfree(rs->buffer);
  87        rs->buffer = NULL;
  88
  89        if ((unsigned)rs->cont_offset > blocksize - min_de_size ||
  90            (unsigned)rs->cont_size > blocksize ||
  91            (unsigned)(rs->cont_offset + rs->cont_size) > blocksize) {
  92                printk(KERN_NOTICE "rock: corrupted directory entry. "
  93                        "extent=%d, offset=%d, size=%d\n",
  94                        rs->cont_extent, rs->cont_offset, rs->cont_size);
  95                ret = -EIO;
  96                goto out;
  97        }
  98
  99        if (rs->cont_extent) {
 100                struct buffer_head *bh;
 101
 102                rs->buffer = kmalloc(rs->cont_size, GFP_KERNEL);
 103                if (!rs->buffer) {
 104                        ret = -ENOMEM;
 105                        goto out;
 106                }
 107                ret = -EIO;
 108                bh = sb_bread(rs->inode->i_sb, rs->cont_extent);
 109                if (bh) {
 110                        memcpy(rs->buffer, bh->b_data + rs->cont_offset,
 111                                        rs->cont_size);
 112                        put_bh(bh);
 113                        rs->chr = rs->buffer;
 114                        rs->len = rs->cont_size;
 115                        rs->cont_extent = 0;
 116                        rs->cont_size = 0;
 117                        rs->cont_offset = 0;
 118                        return 0;
 119                }
 120                printk("Unable to read rock-ridge attributes\n");
 121        }
 122out:
 123        kfree(rs->buffer);
 124        rs->buffer = NULL;
 125        return ret;
 126}
 127
 128/*
 129 * We think there's a record of type `sig' at rs->chr.  Parse the signature
 130 * and make sure that there's really room for a record of that type.
 131 */
 132static int rock_check_overflow(struct rock_state *rs, int sig)
 133{
 134        int len;
 135
 136        switch (sig) {
 137        case SIG('S', 'P'):
 138                len = sizeof(struct SU_SP_s);
 139                break;
 140        case SIG('C', 'E'):
 141                len = sizeof(struct SU_CE_s);
 142                break;
 143        case SIG('E', 'R'):
 144                len = sizeof(struct SU_ER_s);
 145                break;
 146        case SIG('R', 'R'):
 147                len = sizeof(struct RR_RR_s);
 148                break;
 149        case SIG('P', 'X'):
 150                len = sizeof(struct RR_PX_s);
 151                break;
 152        case SIG('P', 'N'):
 153                len = sizeof(struct RR_PN_s);
 154                break;
 155        case SIG('S', 'L'):
 156                len = sizeof(struct RR_SL_s);
 157                break;
 158        case SIG('N', 'M'):
 159                len = sizeof(struct RR_NM_s);
 160                break;
 161        case SIG('C', 'L'):
 162                len = sizeof(struct RR_CL_s);
 163                break;
 164        case SIG('P', 'L'):
 165                len = sizeof(struct RR_PL_s);
 166                break;
 167        case SIG('T', 'F'):
 168                len = sizeof(struct RR_TF_s);
 169                break;
 170        case SIG('Z', 'F'):
 171                len = sizeof(struct RR_ZF_s);
 172                break;
 173        default:
 174                len = 0;
 175                break;
 176        }
 177        len += offsetof(struct rock_ridge, u);
 178        if (len > rs->len) {
 179                printk(KERN_NOTICE "rock: directory entry would overflow "
 180                                "storage\n");
 181                printk(KERN_NOTICE "rock: sig=0x%02x, size=%d, remaining=%d\n",
 182                                sig, len, rs->len);
 183                return -EIO;
 184        }
 185        return 0;
 186}
 187
 188/*
 189 * return length of name field; 0: not found, -1: to be ignored
 190 */
 191int get_rock_ridge_filename(struct iso_directory_record *de,
 192                            char *retname, struct inode *inode)
 193{
 194        struct rock_state rs;
 195        struct rock_ridge *rr;
 196        int sig;
 197        int retnamlen = 0;
 198        int truncate = 0;
 199        int ret = 0;
 200
 201        if (!ISOFS_SB(inode->i_sb)->s_rock)
 202                return 0;
 203        *retname = 0;
 204
 205        init_rock_state(&rs, inode);
 206        setup_rock_ridge(de, inode, &rs);
 207repeat:
 208
 209        while (rs.len > 2) { /* There may be one byte for padding somewhere */
 210                rr = (struct rock_ridge *)rs.chr;
 211                /*
 212                 * Ignore rock ridge info if rr->len is out of range, but
 213                 * don't return -EIO because that would make the file
 214                 * invisible.
 215                 */
 216                if (rr->len < 3)
 217                        goto out;       /* Something got screwed up here */
 218                sig = isonum_721(rs.chr);
 219                if (rock_check_overflow(&rs, sig))
 220                        goto eio;
 221                rs.chr += rr->len;
 222                rs.len -= rr->len;
 223                /*
 224                 * As above, just ignore the rock ridge info if rr->len
 225                 * is bogus.
 226                 */
 227                if (rs.len < 0)
 228                        goto out;       /* Something got screwed up here */
 229
 230                switch (sig) {
 231                case SIG('R', 'R'):
 232                        if ((rr->u.RR.flags[0] & RR_NM) == 0)
 233                                goto out;
 234                        break;
 235                case SIG('S', 'P'):
 236                        if (check_sp(rr, inode))
 237                                goto out;
 238                        break;
 239                case SIG('C', 'E'):
 240                        rs.cont_extent = isonum_733(rr->u.CE.extent);
 241                        rs.cont_offset = isonum_733(rr->u.CE.offset);
 242                        rs.cont_size = isonum_733(rr->u.CE.size);
 243                        break;
 244                case SIG('N', 'M'):
 245                        if (truncate)
 246                                break;
 247                        if (rr->len < 5)
 248                                break;
 249                        /*
 250                         * If the flags are 2 or 4, this indicates '.' or '..'.
 251                         * We don't want to do anything with this, because it
 252                         * screws up the code that calls us.  We don't really
 253                         * care anyways, since we can just use the non-RR
 254                         * name.
 255                         */
 256                        if (rr->u.NM.flags & 6)
 257                                break;
 258
 259                        if (rr->u.NM.flags & ~1) {
 260                                printk("Unsupported NM flag settings (%d)\n",
 261                                        rr->u.NM.flags);
 262                                break;
 263                        }
 264                        if ((strlen(retname) + rr->len - 5) >= 254) {
 265                                truncate = 1;
 266                                break;
 267                        }
 268                        strncat(retname, rr->u.NM.name, rr->len - 5);
 269                        retnamlen += rr->len - 5;
 270                        break;
 271                case SIG('R', 'E'):
 272                        kfree(rs.buffer);
 273                        return -1;
 274                default:
 275                        break;
 276                }
 277        }
 278        ret = rock_continue(&rs);
 279        if (ret == 0)
 280                goto repeat;
 281        if (ret == 1)
 282                return retnamlen; /* If 0, this file did not have a NM field */
 283out:
 284        kfree(rs.buffer);
 285        return ret;
 286eio:
 287        ret = -EIO;
 288        goto out;
 289}
 290
 291static int
 292parse_rock_ridge_inode_internal(struct iso_directory_record *de,
 293                                struct inode *inode, int regard_xa)
 294{
 295        int symlink_len = 0;
 296        int cnt, sig;
 297        struct inode *reloc;
 298        struct rock_ridge *rr;
 299        int rootflag;
 300        struct rock_state rs;
 301        int ret = 0;
 302
 303        if (!ISOFS_SB(inode->i_sb)->s_rock)
 304                return 0;
 305
 306        init_rock_state(&rs, inode);
 307        setup_rock_ridge(de, inode, &rs);
 308        if (regard_xa) {
 309                rs.chr += 14;
 310                rs.len -= 14;
 311                if (rs.len < 0)
 312                        rs.len = 0;
 313        }
 314
 315repeat:
 316        while (rs.len > 2) { /* There may be one byte for padding somewhere */
 317                rr = (struct rock_ridge *)rs.chr;
 318                /*
 319                 * Ignore rock ridge info if rr->len is out of range, but
 320                 * don't return -EIO because that would make the file
 321                 * invisible.
 322                 */
 323                if (rr->len < 3)
 324                        goto out;       /* Something got screwed up here */
 325                sig = isonum_721(rs.chr);
 326                if (rock_check_overflow(&rs, sig))
 327                        goto eio;
 328                rs.chr += rr->len;
 329                rs.len -= rr->len;
 330                /*
 331                 * As above, just ignore the rock ridge info if rr->len
 332                 * is bogus.
 333                 */
 334                if (rs.len < 0)
 335                        goto out;       /* Something got screwed up here */
 336
 337                switch (sig) {
 338#ifndef CONFIG_ZISOFS           /* No flag for SF or ZF */
 339                case SIG('R', 'R'):
 340                        if ((rr->u.RR.flags[0] &
 341                             (RR_PX | RR_TF | RR_SL | RR_CL)) == 0)
 342                                goto out;
 343                        break;
 344#endif
 345                case SIG('S', 'P'):
 346                        if (check_sp(rr, inode))
 347                                goto out;
 348                        break;
 349                case SIG('C', 'E'):
 350                        rs.cont_extent = isonum_733(rr->u.CE.extent);
 351                        rs.cont_offset = isonum_733(rr->u.CE.offset);
 352                        rs.cont_size = isonum_733(rr->u.CE.size);
 353                        break;
 354                case SIG('E', 'R'):
 355                        ISOFS_SB(inode->i_sb)->s_rock = 1;
 356                        printk(KERN_DEBUG "ISO 9660 Extensions: ");
 357                        {
 358                                int p;
 359                                for (p = 0; p < rr->u.ER.len_id; p++)
 360                                        printk("%c", rr->u.ER.data[p]);
 361                        }
 362                        printk("\n");
 363                        break;
 364                case SIG('P', 'X'):
 365                        inode->i_mode = isonum_733(rr->u.PX.mode);
 366                        set_nlink(inode, isonum_733(rr->u.PX.n_links));
 367                        i_uid_write(inode, isonum_733(rr->u.PX.uid));
 368                        i_gid_write(inode, isonum_733(rr->u.PX.gid));
 369                        break;
 370                case SIG('P', 'N'):
 371                        {
 372                                int high, low;
 373                                high = isonum_733(rr->u.PN.dev_high);
 374                                low = isonum_733(rr->u.PN.dev_low);
 375                                /*
 376                                 * The Rock Ridge standard specifies that if
 377                                 * sizeof(dev_t) <= 4, then the high field is
 378                                 * unused, and the device number is completely
 379                                 * stored in the low field.  Some writers may
 380                                 * ignore this subtlety,
 381                                 * and as a result we test to see if the entire
 382                                 * device number is
 383                                 * stored in the low field, and use that.
 384                                 */
 385                                if ((low & ~0xff) && high == 0) {
 386                                        inode->i_rdev =
 387                                            MKDEV(low >> 8, low & 0xff);
 388                                } else {
 389                                        inode->i_rdev =
 390                                            MKDEV(high, low);
 391                                }
 392                        }
 393                        break;
 394                case SIG('T', 'F'):
 395                        /*
 396                         * Some RRIP writers incorrectly place ctime in the
 397                         * TF_CREATE field. Try to handle this correctly for
 398                         * either case.
 399                         */
 400                        /* Rock ridge never appears on a High Sierra disk */
 401                        cnt = 0;
 402                        if (rr->u.TF.flags & TF_CREATE) {
 403                                inode->i_ctime.tv_sec =
 404                                    iso_date(rr->u.TF.times[cnt++].time,
 405                                             0);
 406                                inode->i_ctime.tv_nsec = 0;
 407                        }
 408                        if (rr->u.TF.flags & TF_MODIFY) {
 409                                inode->i_mtime.tv_sec =
 410                                    iso_date(rr->u.TF.times[cnt++].time,
 411                                             0);
 412                                inode->i_mtime.tv_nsec = 0;
 413                        }
 414                        if (rr->u.TF.flags & TF_ACCESS) {
 415                                inode->i_atime.tv_sec =
 416                                    iso_date(rr->u.TF.times[cnt++].time,
 417                                             0);
 418                                inode->i_atime.tv_nsec = 0;
 419                        }
 420                        if (rr->u.TF.flags & TF_ATTRIBUTES) {
 421                                inode->i_ctime.tv_sec =
 422                                    iso_date(rr->u.TF.times[cnt++].time,
 423                                             0);
 424                                inode->i_ctime.tv_nsec = 0;
 425                        }
 426                        break;
 427                case SIG('S', 'L'):
 428                        {
 429                                int slen;
 430                                struct SL_component *slp;
 431                                struct SL_component *oldslp;
 432                                slen = rr->len - 5;
 433                                slp = &rr->u.SL.link;
 434                                inode->i_size = symlink_len;
 435                                while (slen > 1) {
 436                                        rootflag = 0;
 437                                        switch (slp->flags & ~1) {
 438                                        case 0:
 439                                                inode->i_size +=
 440                                                    slp->len;
 441                                                break;
 442                                        case 2:
 443                                                inode->i_size += 1;
 444                                                break;
 445                                        case 4:
 446                                                inode->i_size += 2;
 447                                                break;
 448                                        case 8:
 449                                                rootflag = 1;
 450                                                inode->i_size += 1;
 451                                                break;
 452                                        default:
 453                                                printk("Symlink component flag "
 454                                                        "not implemented\n");
 455                                        }
 456                                        slen -= slp->len + 2;
 457                                        oldslp = slp;
 458                                        slp = (struct SL_component *)
 459                                                (((char *)slp) + slp->len + 2);
 460
 461                                        if (slen < 2) {
 462                                                if (((rr->u.SL.
 463                                                      flags & 1) != 0)
 464                                                    &&
 465                                                    ((oldslp->
 466                                                      flags & 1) == 0))
 467                                                        inode->i_size +=
 468                                                            1;
 469                                                break;
 470                                        }
 471
 472                                        /*
 473                                         * If this component record isn't
 474                                         * continued, then append a '/'.
 475                                         */
 476                                        if (!rootflag
 477                                            && (oldslp->flags & 1) == 0)
 478                                                inode->i_size += 1;
 479                                }
 480                        }
 481                        symlink_len = inode->i_size;
 482                        break;
 483                case SIG('R', 'E'):
 484                        printk(KERN_WARNING "Attempt to read inode for "
 485                                        "relocated directory\n");
 486                        goto out;
 487                case SIG('C', 'L'):
 488                        ISOFS_I(inode)->i_first_extent =
 489                            isonum_733(rr->u.CL.location);
 490                        reloc =
 491                            isofs_iget(inode->i_sb,
 492                                       ISOFS_I(inode)->i_first_extent,
 493                                       0);
 494                        if (IS_ERR(reloc)) {
 495                                ret = PTR_ERR(reloc);
 496                                goto out;
 497                        }
 498                        inode->i_mode = reloc->i_mode;
 499                        set_nlink(inode, reloc->i_nlink);
 500                        inode->i_uid = reloc->i_uid;
 501                        inode->i_gid = reloc->i_gid;
 502                        inode->i_rdev = reloc->i_rdev;
 503                        inode->i_size = reloc->i_size;
 504                        inode->i_blocks = reloc->i_blocks;
 505                        inode->i_atime = reloc->i_atime;
 506                        inode->i_ctime = reloc->i_ctime;
 507                        inode->i_mtime = reloc->i_mtime;
 508                        iput(reloc);
 509                        break;
 510#ifdef CONFIG_ZISOFS
 511                case SIG('Z', 'F'): {
 512                        int algo;
 513
 514                        if (ISOFS_SB(inode->i_sb)->s_nocompress)
 515                                break;
 516                        algo = isonum_721(rr->u.ZF.algorithm);
 517                        if (algo == SIG('p', 'z')) {
 518                                int block_shift =
 519                                        isonum_711(&rr->u.ZF.parms[1]);
 520                                if (block_shift > 17) {
 521                                        printk(KERN_WARNING "isofs: "
 522                                                "Can't handle ZF block "
 523                                                "size of 2^%d\n",
 524                                                block_shift);
 525                                } else {
 526                                        /*
 527                                         * Note: we don't change
 528                                         * i_blocks here
 529                                         */
 530                                        ISOFS_I(inode)->i_file_format =
 531                                                isofs_file_compressed;
 532                                        /*
 533                                         * Parameters to compression
 534                                         * algorithm (header size,
 535                                         * block size)
 536                                         */
 537                                        ISOFS_I(inode)->i_format_parm[0] =
 538                                                isonum_711(&rr->u.ZF.parms[0]);
 539                                        ISOFS_I(inode)->i_format_parm[1] =
 540                                                isonum_711(&rr->u.ZF.parms[1]);
 541                                        inode->i_size =
 542                                            isonum_733(rr->u.ZF.
 543                                                       real_size);
 544                                }
 545                        } else {
 546                                printk(KERN_WARNING
 547                                       "isofs: Unknown ZF compression "
 548                                                "algorithm: %c%c\n",
 549                                       rr->u.ZF.algorithm[0],
 550                                       rr->u.ZF.algorithm[1]);
 551                        }
 552                        break;
 553                }
 554#endif
 555                default:
 556                        break;
 557                }
 558        }
 559        ret = rock_continue(&rs);
 560        if (ret == 0)
 561                goto repeat;
 562        if (ret == 1)
 563                ret = 0;
 564out:
 565        kfree(rs.buffer);
 566        return ret;
 567eio:
 568        ret = -EIO;
 569        goto out;
 570}
 571
 572static char *get_symlink_chunk(char *rpnt, struct rock_ridge *rr, char *plimit)
 573{
 574        int slen;
 575        int rootflag;
 576        struct SL_component *oldslp;
 577        struct SL_component *slp;
 578        slen = rr->len - 5;
 579        slp = &rr->u.SL.link;
 580        while (slen > 1) {
 581                rootflag = 0;
 582                switch (slp->flags & ~1) {
 583                case 0:
 584                        if (slp->len > plimit - rpnt)
 585                                return NULL;
 586                        memcpy(rpnt, slp->text, slp->len);
 587                        rpnt += slp->len;
 588                        break;
 589                case 2:
 590                        if (rpnt >= plimit)
 591                                return NULL;
 592                        *rpnt++ = '.';
 593                        break;
 594                case 4:
 595                        if (2 > plimit - rpnt)
 596                                return NULL;
 597                        *rpnt++ = '.';
 598                        *rpnt++ = '.';
 599                        break;
 600                case 8:
 601                        if (rpnt >= plimit)
 602                                return NULL;
 603                        rootflag = 1;
 604                        *rpnt++ = '/';
 605                        break;
 606                default:
 607                        printk("Symlink component flag not implemented (%d)\n",
 608                               slp->flags);
 609                }
 610                slen -= slp->len + 2;
 611                oldslp = slp;
 612                slp = (struct SL_component *)((char *)slp + slp->len + 2);
 613
 614                if (slen < 2) {
 615                        /*
 616                         * If there is another SL record, and this component
 617                         * record isn't continued, then add a slash.
 618                         */
 619                        if ((!rootflag) && (rr->u.SL.flags & 1) &&
 620                            !(oldslp->flags & 1)) {
 621                                if (rpnt >= plimit)
 622                                        return NULL;
 623                                *rpnt++ = '/';
 624                        }
 625                        break;
 626                }
 627
 628                /*
 629                 * If this component record isn't continued, then append a '/'.
 630                 */
 631                if (!rootflag && !(oldslp->flags & 1)) {
 632                        if (rpnt >= plimit)
 633                                return NULL;
 634                        *rpnt++ = '/';
 635                }
 636        }
 637        return rpnt;
 638}
 639
 640int parse_rock_ridge_inode(struct iso_directory_record *de, struct inode *inode)
 641{
 642        int result = parse_rock_ridge_inode_internal(de, inode, 0);
 643
 644        /*
 645         * if rockridge flag was reset and we didn't look for attributes
 646         * behind eventual XA attributes, have a look there
 647         */
 648        if ((ISOFS_SB(inode->i_sb)->s_rock_offset == -1)
 649            && (ISOFS_SB(inode->i_sb)->s_rock == 2)) {
 650                result = parse_rock_ridge_inode_internal(de, inode, 14);
 651        }
 652        return result;
 653}
 654
 655/*
 656 * readpage() for symlinks: reads symlink contents into the page and either
 657 * makes it uptodate and returns 0 or returns error (-EIO)
 658 */
 659static int rock_ridge_symlink_readpage(struct file *file, struct page *page)
 660{
 661        struct inode *inode = page->mapping->host;
 662        struct iso_inode_info *ei = ISOFS_I(inode);
 663        struct isofs_sb_info *sbi = ISOFS_SB(inode->i_sb);
 664        char *link = kmap(page);
 665        unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
 666        struct buffer_head *bh;
 667        char *rpnt = link;
 668        unsigned char *pnt;
 669        struct iso_directory_record *raw_de;
 670        unsigned long block, offset;
 671        int sig;
 672        struct rock_ridge *rr;
 673        struct rock_state rs;
 674        int ret;
 675
 676        if (!sbi->s_rock)
 677                goto error;
 678
 679        init_rock_state(&rs, inode);
 680        block = ei->i_iget5_block;
 681        bh = sb_bread(inode->i_sb, block);
 682        if (!bh)
 683                goto out_noread;
 684
 685        offset = ei->i_iget5_offset;
 686        pnt = (unsigned char *)bh->b_data + offset;
 687
 688        raw_de = (struct iso_directory_record *)pnt;
 689
 690        /*
 691         * If we go past the end of the buffer, there is some sort of error.
 692         */
 693        if (offset + *pnt > bufsize)
 694                goto out_bad_span;
 695
 696        /*
 697         * Now test for possible Rock Ridge extensions which will override
 698         * some of these numbers in the inode structure.
 699         */
 700
 701        setup_rock_ridge(raw_de, inode, &rs);
 702
 703repeat:
 704        while (rs.len > 2) { /* There may be one byte for padding somewhere */
 705                rr = (struct rock_ridge *)rs.chr;
 706                if (rr->len < 3)
 707                        goto out;       /* Something got screwed up here */
 708                sig = isonum_721(rs.chr);
 709                if (rock_check_overflow(&rs, sig))
 710                        goto out;
 711                rs.chr += rr->len;
 712                rs.len -= rr->len;
 713                if (rs.len < 0)
 714                        goto out;       /* corrupted isofs */
 715
 716                switch (sig) {
 717                case SIG('R', 'R'):
 718                        if ((rr->u.RR.flags[0] & RR_SL) == 0)
 719                                goto out;
 720                        break;
 721                case SIG('S', 'P'):
 722                        if (check_sp(rr, inode))
 723                                goto out;
 724                        break;
 725                case SIG('S', 'L'):
 726                        rpnt = get_symlink_chunk(rpnt, rr,
 727                                                 link + (PAGE_SIZE - 1));
 728                        if (rpnt == NULL)
 729                                goto out;
 730                        break;
 731                case SIG('C', 'E'):
 732                        /* This tells is if there is a continuation record */
 733                        rs.cont_extent = isonum_733(rr->u.CE.extent);
 734                        rs.cont_offset = isonum_733(rr->u.CE.offset);
 735                        rs.cont_size = isonum_733(rr->u.CE.size);
 736                default:
 737                        break;
 738                }
 739        }
 740        ret = rock_continue(&rs);
 741        if (ret == 0)
 742                goto repeat;
 743        if (ret < 0)
 744                goto fail;
 745
 746        if (rpnt == link)
 747                goto fail;
 748        brelse(bh);
 749        *rpnt = '\0';
 750        SetPageUptodate(page);
 751        kunmap(page);
 752        unlock_page(page);
 753        return 0;
 754
 755        /* error exit from macro */
 756out:
 757        kfree(rs.buffer);
 758        goto fail;
 759out_noread:
 760        printk("unable to read i-node block");
 761        goto fail;
 762out_bad_span:
 763        printk("symlink spans iso9660 blocks\n");
 764fail:
 765        brelse(bh);
 766error:
 767        SetPageError(page);
 768        kunmap(page);
 769        unlock_page(page);
 770        return -EIO;
 771}
 772
 773const struct address_space_operations isofs_symlink_aops = {
 774        .readpage = rock_ridge_symlink_readpage
 775};
 776