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
  26 struct 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         int cont_loops;
  34         struct inode *inode;
  35 };
  36
  37 /*
  38  * This is a way of ensuring that we have something in the system
  39  * use fields that is compatible with Rock Ridge.  Return zero on success.
  40  */
  41
  42 static int check_sp(struct rock_ridge *rr, struct inode *inode)
  43 {
  44         if (rr->u.SP.magic[0] != 0xbe)
  45                 return -1;
  46         if (rr->u.SP.magic[1] != 0xef)
  47                 return -1;
  48         ISOFS_SB(inode->i_sb)->s_rock_offset = rr->u.SP.skip;
  49         return 0;
  50 }
  51
  52 static void setup_rock_ridge(struct iso_directory_record *de,
  53                         struct inode *inode, struct rock_state *rs)
  54 {
  55         rs->len = sizeof(struct iso_directory_record) + de->name_len[0];
  56         if (rs->len & 1)
  57                 (rs->len)++;
  58         rs->chr = (unsigned char *)de + rs->len;
  59         rs->len = *((unsigned char *)de) - rs->len;
  60         if (rs->len < 0)
  61                 rs->len = 0;
  62
  63         if (ISOFS_SB(inode->i_sb)->s_rock_offset != -1) {
  64                 rs->len -= ISOFS_SB(inode->i_sb)->s_rock_offset;
  65                 rs->chr += ISOFS_SB(inode->i_sb)->s_rock_offset;
  66                 if (rs->len < 0)
  67                         rs->len = 0;
  68         }
  69 }
  70
  71 static void init_rock_state(struct rock_state *rs, struct inode *inode)
  72 {
  73         memset(rs, 0, sizeof(*rs));
  74         rs->inode = inode;
  75 }
  76
  77 /* Maximum number of Rock Ridge continuation entries */
  78 #define RR_MAX_CE_ENTRIES 32
  79
  80 /*
  81  * Returns 0 if the caller should continue scanning, 1 if the scan must end
  82  * and -ve on error.
  83  */
  84 static int rock_continue(struct rock_state *rs)
  85 {
  86         int ret = 1;
  87         int blocksize = 1 << rs->inode->i_blkbits;
  88         const int min_de_size = offsetof(struct rock_ridge, u);
  89
  90         kfree(rs->buffer);
  91         rs->buffer = NULL;
  92
  93         if ((unsigned)rs->cont_offset > blocksize - min_de_size ||
  94             (unsigned)rs->cont_size > blocksize ||
  95             (unsigned)(rs->cont_offset + rs->cont_size) > blocksize) {
  96                 printk(KERN_NOTICE "rock: corrupted directory entry. "
  97                         "extent=%d, offset=%d, size=%d\n",
  98                         rs->cont_extent, rs->cont_offset, rs->cont_size);
  99                 ret = -EIO;
 100                 goto out;
 101         }
 102
 103         if (rs->cont_extent) {
 104                 struct buffer_head *bh;
 105
 106                 rs->buffer = kmalloc(rs->cont_size, GFP_KERNEL);
 107                 if (!rs->buffer) {
 108                         ret = -ENOMEM;
 109                         goto out;
 110                 }
 111                 ret = -EIO;
 112                 if (++rs->cont_loops >= RR_MAX_CE_ENTRIES)
 113                         goto out;
 114                 bh = sb_bread(rs->inode->i_sb, rs->cont_extent);
 115                 if (bh) {
 116                         memcpy(rs->buffer, bh->b_data + rs->cont_offset,
 117                                         rs->cont_size);
 118                         put_bh(bh);
 119                         rs->chr = rs->buffer;
 120                         rs->len = rs->cont_size;
 121                         rs->cont_extent = 0;
 122                         rs->cont_size = 0;
 123                         rs->cont_offset = 0;
 124                         return 0;
 125                 }
 126                 printk("Unable to read rock-ridge attributes\n");
 127         }
 128 out:
 129         kfree(rs->buffer);
 130         rs->buffer = NULL;
 131         return ret;
 132 }
 133
 134 /*
 135  * We think there's a record of type `sig' at rs->chr.  Parse the signature
 136  * and make sure that there's really room for a record of that type.
 137  */
 138 static int rock_check_overflow(struct rock_state *rs, int sig)
 139 {
 140         int len;
 141
 142         switch (sig) {
 143         case SIG('S', 'P'):
 144                 len = sizeof(struct SU_SP_s);
 145                 break;
 146         case SIG('C', 'E'):
 147                 len = sizeof(struct SU_CE_s);
 148                 break;
 149         case SIG('E', 'R'):
 150                 len = sizeof(struct SU_ER_s);
 151                 break;
 152         case SIG('R', 'R'):
 153                 len = sizeof(struct RR_RR_s);
 154                 break;
 155         case SIG('P', 'X'):
 156                 len = sizeof(struct RR_PX_s);
 157                 break;
 158         case SIG('P', 'N'):
 159                 len = sizeof(struct RR_PN_s);
 160                 break;
 161         case SIG('S', 'L'):
 162                 len = sizeof(struct RR_SL_s);
 163                 break;
 164         case SIG('N', 'M'):
 165                 len = sizeof(struct RR_NM_s);
 166                 break;
 167         case SIG('C', 'L'):
 168                 len = sizeof(struct RR_CL_s);
 169                 break;
 170         case SIG('P', 'L'):
 171                 len = sizeof(struct RR_PL_s);
 172                 break;
 173         case SIG('T', 'F'):
 174                 len = sizeof(struct RR_TF_s);
 175                 break;
 176         case SIG('Z', 'F'):
 177                 len = sizeof(struct RR_ZF_s);
 178                 break;
 179         default:
 180                 len = 0;
 181                 break;
 182         }
 183         len += offsetof(struct rock_ridge, u);
 184         if (len > rs->len) {
 185                 printk(KERN_NOTICE "rock: directory entry would overflow "
 186                                 "storage\n");
 187                 printk(KERN_NOTICE "rock: sig=0x%02x, size=%d, remaining=%d\n",
 188                                 sig, len, rs->len);
 189                 return -EIO;
 190         }
 191         return 0;
 192 }
 193
 194 /*
 195  * return length of name field; 0: not found, -1: to be ignored
 196  */
 197 int get_rock_ridge_filename(struct iso_directory_record *de,
 198                             char *retname, struct inode *inode)
 199 {
 200         struct rock_state rs;
 201         struct rock_ridge *rr;
 202         int sig;
 203         int retnamlen = 0;
 204         int truncate = 0;
 205         int ret = 0;
 206         char *p;
 207         int len;
 208
 209         if (!ISOFS_SB(inode->i_sb)->s_rock)
 210                 return 0;
 211         *retname = 0;
 212
 213         init_rock_state(&rs, inode);
 214         setup_rock_ridge(de, inode, &rs);
 215 repeat:
 216
 217         while (rs.len > 2) { /* There may be one byte for padding somewhere */
 218                 rr = (struct rock_ridge *)rs.chr;
 219                 /*
 220                  * Ignore rock ridge info if rr->len is out of range, but
 221                  * don't return -EIO because that would make the file
 222                  * invisible.
 223                  */
 224                 if (rr->len < 3)
 225                         goto out;       /* Something got screwed up here */
 226                 sig = isonum_721(rs.chr);
 227                 if (rock_check_overflow(&rs, sig))
 228                         goto eio;
 229                 rs.chr += rr->len;
 230                 rs.len -= rr->len;
 231                 /*
 232                  * As above, just ignore the rock ridge info if rr->len
 233                  * is bogus.
 234                  */
 235                 if (rs.len < 0)
 236                         goto out;       /* Something got screwed up here */
 237
 238                 switch (sig) {
 239                 case SIG('R', 'R'):
 240                         if ((rr->u.RR.flags[0] & RR_NM) == 0)
 241                                 goto out;
 242                         break;
 243                 case SIG('S', 'P'):
 244                         if (check_sp(rr, inode))
 245                                 goto out;
 246                         break;
 247                 case SIG('C', 'E'):
 248                         rs.cont_extent = isonum_733(rr->u.CE.extent);
 249                         rs.cont_offset = isonum_733(rr->u.CE.offset);
 250                         rs.cont_size = isonum_733(rr->u.CE.size);
 251                         break;
 252                 case SIG('N', 'M'):
 253                         if (truncate)
 254                                 break;
 255                         if (rr->len < 5)
 256                                 break;
 257                         /*
 258                          * If the flags are 2 or 4, this indicates '.' or '..'.
 259                          * We don't want to do anything with this, because it
 260                          * screws up the code that calls us.  We don't really
 261                          * care anyways, since we can just use the non-RR
 262                          * name.
 263                          */
 264                         if (rr->u.NM.flags & 6)
 265                                 break;
 266
 267                         if (rr->u.NM.flags & ~1) {
 268                                 printk("Unsupported NM flag settings (%d)\n",
 269                                         rr->u.NM.flags);
 270                                 break;
 271                         }
 272                         len = rr->len - 5;
 273                         if (retnamlen + len >= 254) {
 274                                 truncate = 1;
 275                                 break;
 276                         }
 277                         p = memchr(rr->u.NM.name, '\0', len);
 278                         if (unlikely(p))
 279                                 len = p - rr->u.NM.name;
 280                         memcpy(retname + retnamlen, rr->u.NM.name, len);
 281                         retnamlen += len;
 282                         retname[retnamlen] = '\0';
 283                         break;
 284                 case SIG('R', 'E'):
 285                         kfree(rs.buffer);
 286                         return -1;
 287                 default:
 288                         break;
 289                 }
 290         }
 291         ret = rock_continue(&rs);
 292         if (ret == 0)
 293                 goto repeat;
 294         if (ret == 1)
 295                 return retnamlen; /* If 0, this file did not have a NM field */
 296 out:
 297         kfree(rs.buffer);
 298         return ret;
 299 eio:
 300         ret = -EIO;
 301         goto out;
 302 }
 303
 304 #define RR_REGARD_XA 1
 305 #define RR_RELOC_DE 2
 306
 307 static int
 308 parse_rock_ridge_inode_internal(struct iso_directory_record *de,
 309                                 struct inode *inode, int flags)
 310 {
 311         int symlink_len = 0;
 312         int cnt, sig;
 313         unsigned int reloc_block;
 314         struct inode *reloc;
 315         struct rock_ridge *rr;
 316         int rootflag;
 317         struct rock_state rs;
 318         int ret = 0;
 319
 320         if (!ISOFS_SB(inode->i_sb)->s_rock)
 321                 return 0;
 322
 323         init_rock_state(&rs, inode);
 324         setup_rock_ridge(de, inode, &rs);
 325         if (flags & RR_REGARD_XA) {
 326                 rs.chr += 14;
 327                 rs.len -= 14;
 328                 if (rs.len < 0)
 329                         rs.len = 0;
 330         }
 331
 332 repeat:
 333         while (rs.len > 2) { /* There may be one byte for padding somewhere */
 334                 rr = (struct rock_ridge *)rs.chr;
 335                 /*
 336                  * Ignore rock ridge info if rr->len is out of range, but
 337                  * don't return -EIO because that would make the file
 338                  * invisible.
 339                  */
 340                 if (rr->len < 3)
 341                         goto out;       /* Something got screwed up here */
 342                 sig = isonum_721(rs.chr);
 343                 if (rock_check_overflow(&rs, sig))
 344                         goto eio;
 345                 rs.chr += rr->len;
 346                 rs.len -= rr->len;
 347                 /*
 348                  * As above, just ignore the rock ridge info if rr->len
 349                  * is bogus.
 350                  */
 351                 if (rs.len < 0)
 352                         goto out;       /* Something got screwed up here */
 353
 354                 switch (sig) {
 355 #ifndef CONFIG_ZISOFS           /* No flag for SF or ZF */
 356                 case SIG('R', 'R'):
 357                         if ((rr->u.RR.flags[0] &
 358                              (RR_PX | RR_TF | RR_SL | RR_CL)) == 0)
 359                                 goto out;
 360                         break;
 361 #endif
 362                 case SIG('S', 'P'):
 363                         if (check_sp(rr, inode))
 364                                 goto out;
 365                         break;
 366                 case SIG('C', 'E'):
 367                         rs.cont_extent = isonum_733(rr->u.CE.extent);
 368                         rs.cont_offset = isonum_733(rr->u.CE.offset);
 369                         rs.cont_size = isonum_733(rr->u.CE.size);
 370                         break;
 371                 case SIG('E', 'R'):
 372                         /* Invalid length of ER tag id? */
 373                         if (rr->u.ER.len_id + offsetof(struct rock_ridge, u.ER.data) > rr->len)
 374                                 goto out;
 375                         ISOFS_SB(inode->i_sb)->s_rock = 1;
 376                         printk(KERN_DEBUG "ISO 9660 Extensions: ");
 377                         {
 378                                 int p;
 379                                 for (p = 0; p < rr->u.ER.len_id; p++)
 380                                         printk("%c", rr->u.ER.data[p]);
 381                         }
 382                         printk("\n");
 383                         break;
 384                 case SIG('P', 'X'):
 385                         inode->i_mode = isonum_733(rr->u.PX.mode);
 386                         set_nlink(inode, isonum_733(rr->u.PX.n_links));
 387                         i_uid_write(inode, isonum_733(rr->u.PX.uid));
 388                         i_gid_write(inode, isonum_733(rr->u.PX.gid));
 389                         break;
 390                 case SIG('P', 'N'):
 391                         {
 392                                 int high, low;
 393                                 high = isonum_733(rr->u.PN.dev_high);
 394                                 low = isonum_733(rr->u.PN.dev_low);
 395                                 /*
 396                                  * The Rock Ridge standard specifies that if
 397                                  * sizeof(dev_t) <= 4, then the high field is
 398                                  * unused, and the device number is completely
 399                                  * stored in the low field.  Some writers may
 400                                  * ignore this subtlety,
 401                                  * and as a result we test to see if the entire
 402                                  * device number is
 403                                  * stored in the low field, and use that.
 404                                  */
 405                                 if ((low & ~0xff) && high == 0) {
 406                                         inode->i_rdev =
 407                                             MKDEV(low >> 8, low & 0xff);
 408                                 } else {
 409                                         inode->i_rdev =
 410                                             MKDEV(high, low);
 411                                 }
 412                         }
 413                         break;
 414                 case SIG('T', 'F'):
 415                         /*
 416                          * Some RRIP writers incorrectly place ctime in the
 417                          * TF_CREATE field. Try to handle this correctly for
 418                          * either case.
 419                          */
 420                         /* Rock ridge never appears on a High Sierra disk */
 421                         cnt = 0;
 422                         if (rr->u.TF.flags & TF_CREATE) {
 423                                 inode->i_ctime.tv_sec =
 424                                     iso_date(rr->u.TF.times[cnt++].time,
 425                                              0);
 426                                 inode->i_ctime.tv_nsec = 0;
 427                         }
 428                         if (rr->u.TF.flags & TF_MODIFY) {
 429                                 inode->i_mtime.tv_sec =
 430                                     iso_date(rr->u.TF.times[cnt++].time,
 431                                              0);
 432                                 inode->i_mtime.tv_nsec = 0;
 433                         }
 434                         if (rr->u.TF.flags & TF_ACCESS) {
 435                                 inode->i_atime.tv_sec =
 436                                     iso_date(rr->u.TF.times[cnt++].time,
 437                                              0);
 438                                 inode->i_atime.tv_nsec = 0;
 439                         }
 440                         if (rr->u.TF.flags & TF_ATTRIBUTES) {
 441                                 inode->i_ctime.tv_sec =
 442                                     iso_date(rr->u.TF.times[cnt++].time,
 443                                              0);
 444                                 inode->i_ctime.tv_nsec = 0;
 445                         }
 446                         break;
 447                 case SIG('S', 'L'):
 448                         {
 449                                 int slen;
 450                                 struct SL_component *slp;
 451                                 struct SL_component *oldslp;
 452                                 slen = rr->len - 5;
 453                                 slp = &rr->u.SL.link;
 454                                 inode->i_size = symlink_len;
 455                                 while (slen > 1) {
 456                                         rootflag = 0;
 457                                         switch (slp->flags & ~1) {
 458                                         case 0:
 459                                                 inode->i_size +=
 460                                                     slp->len;
 461                                                 break;
 462                                         case 2:
 463                                                 inode->i_size += 1;
 464                                                 break;
 465                                         case 4:
 466                                                 inode->i_size += 2;
 467                                                 break;
 468                                         case 8:
 469                                                 rootflag = 1;
 470                                                 inode->i_size += 1;
 471                                                 break;
 472                                         default:
 473                                                 printk("Symlink component flag "
 474                                                         "not implemented\n");
 475                                         }
 476                                         slen -= slp->len + 2;
 477                                         oldslp = slp;
 478                                         slp = (struct SL_component *)
 479                                                 (((char *)slp) + slp->len + 2);
 480
 481                                         if (slen < 2) {
 482                                                 if (((rr->u.SL.
 483                                                       flags & 1) != 0)
 484                                                     &&
 485                                                     ((oldslp->
 486                                                       flags & 1) == 0))
 487                                                         inode->i_size +=
 488                                                             1;
 489                                                 break;
 490                                         }
 491
 492                                         /*
 493                                          * If this component record isn't
 494                                          * continued, then append a '/'.
 495                                          */
 496                                         if (!rootflag
 497                                             && (oldslp->flags & 1) == 0)
 498                                                 inode->i_size += 1;
 499                                 }
 500                         }
 501                         symlink_len = inode->i_size;
 502                         break;
 503                 case SIG('R', 'E'):
 504                         printk(KERN_WARNING "Attempt to read inode for "
 505                                         "relocated directory\n");
 506                         goto out;
 507                 case SIG('C', 'L'):
 508                         if (flags & RR_RELOC_DE) {
 509                                 printk(KERN_ERR
 510                                        "ISOFS: Recursive directory relocation "
 511                                        "is not supported\n");
 512                                 goto eio;
 513                         }
 514                         reloc_block = isonum_733(rr->u.CL.location);
 515                         if (reloc_block == ISOFS_I(inode)->i_iget5_block &&
 516                             ISOFS_I(inode)->i_iget5_offset == 0) {
 517                                 printk(KERN_ERR
 518                                        "ISOFS: Directory relocation points to "
 519                                        "itself\n");
 520                                 goto eio;
 521                         }
 522                         ISOFS_I(inode)->i_first_extent = reloc_block;
 523                         reloc = isofs_iget_reloc(inode->i_sb, reloc_block, 0);
 524                         if (IS_ERR(reloc)) {
 525                                 ret = PTR_ERR(reloc);
 526                                 goto out;
 527                         }
 528                         inode->i_mode = reloc->i_mode;
 529                         set_nlink(inode, reloc->i_nlink);
 530                         inode->i_uid = reloc->i_uid;
 531                         inode->i_gid = reloc->i_gid;
 532                         inode->i_rdev = reloc->i_rdev;
 533                         inode->i_size = reloc->i_size;
 534                         inode->i_blocks = reloc->i_blocks;
 535                         inode->i_atime = reloc->i_atime;
 536                         inode->i_ctime = reloc->i_ctime;
 537                         inode->i_mtime = reloc->i_mtime;
 538                         iput(reloc);
 539                         break;
 540 #ifdef CONFIG_ZISOFS
 541                 case SIG('Z', 'F'): {
 542                         int algo;
 543
 544                         if (ISOFS_SB(inode->i_sb)->s_nocompress)
 545                                 break;
 546                         algo = isonum_721(rr->u.ZF.algorithm);
 547                         if (algo == SIG('p', 'z')) {
 548                                 int block_shift =
 549                                         isonum_711(&rr->u.ZF.parms[1]);
 550                                 if (block_shift > 17) {
 551                                         printk(KERN_WARNING "isofs: "
 552                                                 "Can't handle ZF block "
 553                                                 "size of 2^%d\n",
 554                                                 block_shift);
 555                                 } else {
 556                                         /*
 557                                          * Note: we don't change
 558                                          * i_blocks here
 559                                          */
 560                                         ISOFS_I(inode)->i_file_format =
 561                                                 isofs_file_compressed;
 562                                         /*
 563                                          * Parameters to compression
 564                                          * algorithm (header size,
 565                                          * block size)
 566                                          */
 567                                         ISOFS_I(inode)->i_format_parm[0] =
 568                                                 isonum_711(&rr->u.ZF.parms[0]);
 569                                         ISOFS_I(inode)->i_format_parm[1] =
 570                                                 isonum_711(&rr->u.ZF.parms[1]);
 571                                         inode->i_size =
 572                                             isonum_733(rr->u.ZF.
 573                                                        real_size);
 574                                 }
 575                         } else {
 576                                 printk(KERN_WARNING
 577                                        "isofs: Unknown ZF compression "
 578                                                 "algorithm: %c%c\n",
 579                                        rr->u.ZF.algorithm[0],
 580                                        rr->u.ZF.algorithm[1]);
 581                         }
 582                         break;
 583                 }
 584 #endif
 585                 default:
 586                         break;
 587                 }
 588         }
 589         ret = rock_continue(&rs);
 590         if (ret == 0)
 591                 goto repeat;
 592         if (ret == 1)
 593                 ret = 0;
 594 out:
 595         kfree(rs.buffer);
 596         return ret;
 597 eio:
 598         ret = -EIO;
 599         goto out;
 600 }
 601
 602 static char *get_symlink_chunk(char *rpnt, struct rock_ridge *rr, char *plimit)
 603 {
 604         int slen;
 605         int rootflag;
 606         struct SL_component *oldslp;
 607         struct SL_component *slp;
 608         slen = rr->len - 5;
 609         slp = &rr->u.SL.link;
 610         while (slen > 1) {
 611                 rootflag = 0;
 612                 switch (slp->flags & ~1) {
 613                 case 0:
 614                         if (slp->len > plimit - rpnt)
 615                                 return NULL;
 616                         memcpy(rpnt, slp->text, slp->len);
 617                         rpnt += slp->len;
 618                         break;
 619                 case 2:
 620                         if (rpnt >= plimit)
 621                                 return NULL;
 622                         *rpnt++ = '.';
 623                         break;
 624                 case 4:
 625                         if (2 > plimit - rpnt)
 626                                 return NULL;
 627                         *rpnt++ = '.';
 628                         *rpnt++ = '.';
 629                         break;
 630                 case 8:
 631                         if (rpnt >= plimit)
 632                                 return NULL;
 633                         rootflag = 1;
 634                         *rpnt++ = '/';
 635                         break;
 636                 default:
 637                         printk("Symlink component flag not implemented (%d)\n",
 638                                slp->flags);
 639                 }
 640                 slen -= slp->len + 2;
 641                 oldslp = slp;
 642                 slp = (struct SL_component *)((char *)slp + slp->len + 2);
 643
 644                 if (slen < 2) {
 645                         /*
 646                          * If there is another SL record, and this component
 647                          * record isn't continued, then add a slash.
 648                          */
 649                         if ((!rootflag) && (rr->u.SL.flags & 1) &&
 650                             !(oldslp->flags & 1)) {
 651                                 if (rpnt >= plimit)
 652                                         return NULL;
 653                                 *rpnt++ = '/';
 654                         }
 655                         break;
 656                 }
 657
 658                 /*
 659                  * If this component record isn't continued, then append a '/'.
 660                  */
 661                 if (!rootflag && !(oldslp->flags & 1)) {
 662                         if (rpnt >= plimit)
 663                                 return NULL;
 664                         *rpnt++ = '/';
 665                 }
 666         }
 667         return rpnt;
 668 }
 669
 670 int parse_rock_ridge_inode(struct iso_directory_record *de, struct inode *inode,
 671                            int relocated)
 672 {
 673         int flags = relocated ? RR_RELOC_DE : 0;
 674         int result = parse_rock_ridge_inode_internal(de, inode, flags);
 675
 676         /*
 677          * if rockridge flag was reset and we didn't look for attributes
 678          * behind eventual XA attributes, have a look there
 679          */
 680         if ((ISOFS_SB(inode->i_sb)->s_rock_offset == -1)
 681             && (ISOFS_SB(inode->i_sb)->s_rock == 2)) {
 682                 result = parse_rock_ridge_inode_internal(de, inode,
 683                                                          flags | RR_REGARD_XA);
 684         }
 685         return result;
 686 }
 687
 688 /*
 689  * readpage() for symlinks: reads symlink contents into the page and either
 690  * makes it uptodate and returns 0 or returns error (-EIO)
 691  */
 692 static int rock_ridge_symlink_readpage(struct file *file, struct page *page)
 693 {
 694         struct inode *inode = page->mapping->host;
 695         struct iso_inode_info *ei = ISOFS_I(inode);
 696         struct isofs_sb_info *sbi = ISOFS_SB(inode->i_sb);
 697         char *link = kmap(page);
 698         unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
 699         struct buffer_head *bh;
 700         char *rpnt = link;
 701         unsigned char *pnt;
 702         struct iso_directory_record *raw_de;
 703         unsigned long block, offset;
 704         int sig;
 705         struct rock_ridge *rr;
 706         struct rock_state rs;
 707         int ret;
 708
 709         if (!sbi->s_rock)
 710                 goto error;
 711
 712         init_rock_state(&rs, inode);
 713         block = ei->i_iget5_block;
 714         bh = sb_bread(inode->i_sb, block);
 715         if (!bh)
 716                 goto out_noread;
 717
 718         offset = ei->i_iget5_offset;
 719         pnt = (unsigned char *)bh->b_data + offset;
 720
 721         raw_de = (struct iso_directory_record *)pnt;
 722
 723         /*
 724          * If we go past the end of the buffer, there is some sort of error.
 725          */
 726         if (offset + *pnt > bufsize)
 727                 goto out_bad_span;
 728
 729         /*
 730          * Now test for possible Rock Ridge extensions which will override
 731          * some of these numbers in the inode structure.
 732          */
 733
 734         setup_rock_ridge(raw_de, inode, &rs);
 735
 736 repeat:
 737         while (rs.len > 2) { /* There may be one byte for padding somewhere */
 738                 rr = (struct rock_ridge *)rs.chr;
 739                 if (rr->len < 3)
 740                         goto out;       /* Something got screwed up here */
 741                 sig = isonum_721(rs.chr);
 742                 if (rock_check_overflow(&rs, sig))
 743                         goto out;
 744                 rs.chr += rr->len;
 745                 rs.len -= rr->len;
 746                 if (rs.len < 0)
 747                         goto out;       /* corrupted isofs */
 748
 749                 switch (sig) {
 750                 case SIG('R', 'R'):
 751                         if ((rr->u.RR.flags[0] & RR_SL) == 0)
 752                                 goto out;
 753                         break;
 754                 case SIG('S', 'P'):
 755                         if (check_sp(rr, inode))
 756                                 goto out;
 757                         break;
 758                 case SIG('S', 'L'):
 759                         rpnt = get_symlink_chunk(rpnt, rr,
 760                                                  link + (PAGE_SIZE - 1));
 761                         if (rpnt == NULL)
 762                                 goto out;
 763                         break;
 764                 case SIG('C', 'E'):
 765                         /* This tells is if there is a continuation record */
 766                         rs.cont_extent = isonum_733(rr->u.CE.extent);
 767                         rs.cont_offset = isonum_733(rr->u.CE.offset);
 768                         rs.cont_size = isonum_733(rr->u.CE.size);
 769                 default:
 770                         break;
 771                 }
 772         }
 773         ret = rock_continue(&rs);
 774         if (ret == 0)
 775                 goto repeat;
 776         if (ret < 0)
 777                 goto fail;
 778
 779         if (rpnt == link)
 780                 goto fail;
 781         brelse(bh);
 782         *rpnt = '\0';
 783         SetPageUptodate(page);
 784         kunmap(page);
 785         unlock_page(page);
 786         return 0;
 787
 788         /* error exit from macro */
 789 out:
 790         kfree(rs.buffer);
 791         goto fail;
 792 out_noread:
 793         printk("unable to read i-node block");
 794         goto fail;
 795 out_bad_span:
 796         printk("symlink spans iso9660 blocks\n");
 797 fail:
 798         brelse(bh);
 799 error:
 800         SetPageError(page);
 801         kunmap(page);
 802         unlock_page(page);
 803         return -EIO;
 804 }
 805
 806 const struct address_space_operations isofs_symlink_aops = {
 807         .readpage = rock_ridge_symlink_readpage
 808 };