drivers/mtd/nftlmount.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * NFTL mount code with extensive checks
   4  *
   5  * Author: Fabrice Bellard (fabrice.bellard@netgem.com)
   6  * Copyright © 2000 Netgem S.A.
   7  * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <asm/errno.h>
  12 #include <linux/delay.h>
  13 #include <linux/slab.h>
  14 #include <linux/mtd/mtd.h>
  15 #include <linux/mtd/rawnand.h>
  16 #include <linux/mtd/nftl.h>
  17
  18 #define SECTORSIZE 512
  19
  20 /* find_boot_record: Find the NFTL Media Header and its Spare copy which contains the
  21  *      various device information of the NFTL partition and Bad Unit Table. Update
  22  *      the ReplUnitTable[] table according to the Bad Unit Table. ReplUnitTable[]
  23  *      is used for management of Erase Unit in other routines in nftl.c and nftlmount.c
  24  */
  25 static int find_boot_record(struct NFTLrecord *nftl)
  26 {
  27         struct nftl_uci1 h1;
  28         unsigned int block, boot_record_count = 0;
  29         size_t retlen;
  30         u8 buf[SECTORSIZE];
  31         struct NFTLMediaHeader *mh = &nftl->MediaHdr;
  32         struct mtd_info *mtd = nftl->mbd.mtd;
  33         unsigned int i;
  34
  35         /* Assume logical EraseSize == physical erasesize for starting the scan.
  36            We'll sort it out later if we find a MediaHeader which says otherwise */
  37         /* Actually, we won't.  The new DiskOnChip driver has already scanned
  38            the MediaHeader and adjusted the virtual erasesize it presents in
  39            the mtd device accordingly.  We could even get rid of
  40            nftl->EraseSize if there were any point in doing so. */
  41         nftl->EraseSize = nftl->mbd.mtd->erasesize;
  42         nftl->nb_blocks = (u32)nftl->mbd.mtd->size / nftl->EraseSize;
  43
  44         nftl->MediaUnit = BLOCK_NIL;
  45         nftl->SpareMediaUnit = BLOCK_NIL;
  46
  47         /* search for a valid boot record */
  48         for (block = 0; block < nftl->nb_blocks; block++) {
  49                 int ret;
  50
  51                 /* Check for ANAND header first. Then can whinge if it's found but later
  52                    checks fail */
  53                 ret = mtd_read(mtd, block * nftl->EraseSize, SECTORSIZE,
  54                                &retlen, buf);
  55                 /* We ignore ret in case the ECC of the MediaHeader is invalid
  56                    (which is apparently acceptable) */
  57                 if (retlen != SECTORSIZE) {
  58                         static int warncount = 5;
  59
  60                         if (warncount) {
  61                                 printk(KERN_WARNING "Block read at 0x%x of mtd%d failed: %d\n",
  62                                        block * nftl->EraseSize, nftl->mbd.mtd->index, ret);
  63                                 if (!--warncount)
  64                                         printk(KERN_WARNING "Further failures for this block will not be printed\n");
  65                         }
  66                         continue;
  67                 }
  68
  69                 if (retlen < 6 || memcmp(buf, "ANAND", 6)) {
  70                         /* ANAND\0 not found. Continue */
  71 #if 0
  72                         printk(KERN_DEBUG "ANAND header not found at 0x%x in mtd%d\n",
  73                                block * nftl->EraseSize, nftl->mbd.mtd->index);
  74 #endif
  75                         continue;
  76                 }
  77
  78                 /* To be safer with BIOS, also use erase mark as discriminant */
  79                 ret = nftl_read_oob(mtd, block * nftl->EraseSize +
  80                                          SECTORSIZE + 8, 8, &retlen,
  81                                          (char *)&h1);
  82                 if (ret < 0) {
  83                         printk(KERN_WARNING "ANAND header found at 0x%x in mtd%d, but OOB data read failed (err %d)\n",
  84                                block * nftl->EraseSize, nftl->mbd.mtd->index, ret);
  85                         continue;
  86                 }
  87
  88 #if 0 /* Some people seem to have devices without ECC or erase marks
  89          on the Media Header blocks. There are enough other sanity
  90          checks in here that we can probably do without it.
  91       */
  92                 if (le16_to_cpu(h1.EraseMark | h1.EraseMark1) != ERASE_MARK) {
  93                         printk(KERN_NOTICE "ANAND header found at 0x%x in mtd%d, but erase mark not present (0x%04x,0x%04x instead)\n",
  94                                block * nftl->EraseSize, nftl->mbd.mtd->index,
  95                                le16_to_cpu(h1.EraseMark), le16_to_cpu(h1.EraseMark1));
  96                         continue;
  97                 }
  98
  99                 /* Finally reread to check ECC */
 100                 ret = mtd->read(mtd, block * nftl->EraseSize, SECTORSIZE,
 101                                 &retlen, buf);
 102                 if (ret < 0) {
 103                         printk(KERN_NOTICE "ANAND header found at 0x%x in mtd%d, but ECC read failed (err %d)\n",
 104                                block * nftl->EraseSize, nftl->mbd.mtd->index, ret);
 105                         continue;
 106                 }
 107
 108                 /* Paranoia. Check the ANAND header is still there after the ECC read */
 109                 if (memcmp(buf, "ANAND", 6)) {
 110                         printk(KERN_NOTICE "ANAND header found at 0x%x in mtd%d, but went away on reread!\n",
 111                                block * nftl->EraseSize, nftl->mbd.mtd->index);
 112                         printk(KERN_NOTICE "New data are: %6ph\n", buf);
 113                         continue;
 114                 }
 115 #endif
 116                 /* OK, we like it. */
 117
 118                 if (boot_record_count) {
 119                         /* We've already processed one. So we just check if
 120                            this one is the same as the first one we found */
 121                         if (memcmp(mh, buf, sizeof(struct NFTLMediaHeader))) {
 122                                 printk(KERN_NOTICE "NFTL Media Headers at 0x%x and 0x%x disagree.\n",
 123                                        nftl->MediaUnit * nftl->EraseSize, block * nftl->EraseSize);
 124                                 /* if (debug) Print both side by side */
 125                                 if (boot_record_count < 2) {
 126                                         /* We haven't yet seen two real ones */
 127                                         return -1;
 128                                 }
 129                                 continue;
 130                         }
 131                         if (boot_record_count == 1)
 132                                 nftl->SpareMediaUnit = block;
 133
 134                         /* Mark this boot record (NFTL MediaHeader) block as reserved */
 135                         nftl->ReplUnitTable[block] = BLOCK_RESERVED;
 136
 137
 138                         boot_record_count++;
 139                         continue;
 140                 }
 141
 142                 /* This is the first we've seen. Copy the media header structure into place */
 143                 memcpy(mh, buf, sizeof(struct NFTLMediaHeader));
 144
 145                 /* Do some sanity checks on it */
 146 #if 0
 147 The new DiskOnChip driver scans the MediaHeader itself, and presents a virtual
 148 erasesize based on UnitSizeFactor.  So the erasesize we read from the mtd
 149 device is already correct.
 150                 if (mh->UnitSizeFactor == 0) {
 151                         printk(KERN_NOTICE "NFTL: UnitSizeFactor 0x00 detected. This violates the spec but we think we know what it means...\n");
 152                 } else if (mh->UnitSizeFactor < 0xfc) {
 153                         printk(KERN_NOTICE "Sorry, we don't support UnitSizeFactor 0x%02x\n",
 154                                mh->UnitSizeFactor);
 155                         return -1;
 156                 } else if (mh->UnitSizeFactor != 0xff) {
 157                         printk(KERN_NOTICE "WARNING: Support for NFTL with UnitSizeFactor 0x%02x is experimental\n",
 158                                mh->UnitSizeFactor);
 159                         nftl->EraseSize = nftl->mbd.mtd->erasesize << (0xff - mh->UnitSizeFactor);
 160                         nftl->nb_blocks = (u32)nftl->mbd.mtd->size / nftl->EraseSize;
 161                 }
 162 #endif
 163                 nftl->nb_boot_blocks = le16_to_cpu(mh->FirstPhysicalEUN);
 164                 if ((nftl->nb_boot_blocks + 2) >= nftl->nb_blocks) {
 165                         printk(KERN_NOTICE "NFTL Media Header sanity check failed:\n");
 166                         printk(KERN_NOTICE "nb_boot_blocks (%d) + 2 > nb_blocks (%d)\n",
 167                                nftl->nb_boot_blocks, nftl->nb_blocks);
 168                         return -1;
 169                 }
 170
 171                 nftl->numvunits = le32_to_cpu(mh->FormattedSize) / nftl->EraseSize;
 172                 if (nftl->numvunits > (nftl->nb_blocks - nftl->nb_boot_blocks - 2)) {
 173                         printk(KERN_NOTICE "NFTL Media Header sanity check failed:\n");
 174                         printk(KERN_NOTICE "numvunits (%d) > nb_blocks (%d) - nb_boot_blocks(%d) - 2\n",
 175                                nftl->numvunits, nftl->nb_blocks, nftl->nb_boot_blocks);
 176                         return -1;
 177                 }
 178
 179                 nftl->mbd.size  = nftl->numvunits * (nftl->EraseSize / SECTORSIZE);
 180
 181                 /* If we're not using the last sectors in the device for some reason,
 182                    reduce nb_blocks accordingly so we forget they're there */
 183                 nftl->nb_blocks = le16_to_cpu(mh->NumEraseUnits) + le16_to_cpu(mh->FirstPhysicalEUN);
 184
 185                 /* XXX: will be suppressed */
 186                 nftl->lastEUN = nftl->nb_blocks - 1;
 187
 188                 /* memory alloc */
 189                 nftl->EUNtable = kmalloc_array(nftl->nb_blocks, sizeof(u16),
 190                                                GFP_KERNEL);
 191                 if (!nftl->EUNtable) {
 192                         printk(KERN_NOTICE "NFTL: allocation of EUNtable failed\n");
 193                         return -ENOMEM;
 194                 }
 195
 196                 nftl->ReplUnitTable = kmalloc_array(nftl->nb_blocks,
 197                                                     sizeof(u16),
 198                                                     GFP_KERNEL);
 199                 if (!nftl->ReplUnitTable) {
 200                         kfree(nftl->EUNtable);
 201                         printk(KERN_NOTICE "NFTL: allocation of ReplUnitTable failed\n");
 202                         return -ENOMEM;
 203                 }
 204
 205                 /* mark the bios blocks (blocks before NFTL MediaHeader) as reserved */
 206                 for (i = 0; i < nftl->nb_boot_blocks; i++)
 207                         nftl->ReplUnitTable[i] = BLOCK_RESERVED;
 208                 /* mark all remaining blocks as potentially containing data */
 209                 for (; i < nftl->nb_blocks; i++) {
 210                         nftl->ReplUnitTable[i] = BLOCK_NOTEXPLORED;
 211                 }
 212
 213                 /* Mark this boot record (NFTL MediaHeader) block as reserved */
 214                 nftl->ReplUnitTable[block] = BLOCK_RESERVED;
 215
 216                 /* read the Bad Erase Unit Table and modify ReplUnitTable[] accordingly */
 217                 for (i = 0; i < nftl->nb_blocks; i++) {
 218 #if 0
 219 The new DiskOnChip driver already scanned the bad block table.  Just query it.
 220                         if ((i & (SECTORSIZE - 1)) == 0) {
 221                                 /* read one sector for every SECTORSIZE of blocks */
 222                                 ret = mtd->read(nftl->mbd.mtd,
 223                                                 block * nftl->EraseSize + i +
 224                                                 SECTORSIZE, SECTORSIZE,
 225                                                 &retlen, buf);
 226                                 if (ret < 0) {
 227                                         printk(KERN_NOTICE "Read of bad sector table failed (err %d)\n",
 228                                                ret);
 229                                         kfree(nftl->ReplUnitTable);
 230                                         kfree(nftl->EUNtable);
 231                                         return -1;
 232                                 }
 233                         }
 234                         /* mark the Bad Erase Unit as RESERVED in ReplUnitTable */
 235                         if (buf[i & (SECTORSIZE - 1)] != 0xff)
 236                                 nftl->ReplUnitTable[i] = BLOCK_RESERVED;
 237 #endif
 238                         if (mtd_block_isbad(nftl->mbd.mtd,
 239                                             i * nftl->EraseSize))
 240                                 nftl->ReplUnitTable[i] = BLOCK_RESERVED;
 241                 }
 242
 243                 nftl->MediaUnit = block;
 244                 boot_record_count++;
 245
 246         } /* foreach (block) */
 247
 248         return boot_record_count?0:-1;
 249 }
 250
 251 static int memcmpb(void *a, int c, int n)
 252 {
 253         int i;
 254         for (i = 0; i < n; i++) {
 255                 if (c != ((unsigned char *)a)[i])
 256                         return 1;
 257         }
 258         return 0;
 259 }
 260
 261 /* check_free_sector: check if a free sector is actually FREE, i.e. All 0xff in data and oob area */
 262 static int check_free_sectors(struct NFTLrecord *nftl, unsigned int address, int len,
 263                               int check_oob)
 264 {
 265         struct mtd_info *mtd = nftl->mbd.mtd;
 266         size_t retlen;
 267         int i, ret;
 268         u8 *buf;
 269
 270         buf = kmalloc(SECTORSIZE + mtd->oobsize, GFP_KERNEL);
 271         if (!buf)
 272                 return -1;
 273
 274         ret = -1;
 275         for (i = 0; i < len; i += SECTORSIZE) {
 276                 if (mtd_read(mtd, address, SECTORSIZE, &retlen, buf))
 277                         goto out;
 278                 if (memcmpb(buf, 0xff, SECTORSIZE) != 0)
 279                         goto out;
 280
 281                 if (check_oob) {
 282                         if(nftl_read_oob(mtd, address, mtd->oobsize,
 283                                          &retlen, &buf[SECTORSIZE]) < 0)
 284                                 goto out;
 285                         if (memcmpb(buf + SECTORSIZE, 0xff, mtd->oobsize) != 0)
 286                                 goto out;
 287                 }
 288                 address += SECTORSIZE;
 289         }
 290
 291         ret = 0;
 292
 293 out:
 294         kfree(buf);
 295         return ret;
 296 }
 297
 298 /* NFTL_format: format a Erase Unit by erasing ALL Erase Zones in the Erase Unit and
 299  *              Update NFTL metadata. Each erase operation is checked with check_free_sectors
 300  *
 301  * Return: 0 when succeed, -1 on error.
 302  *
 303  *  ToDo: 1. Is it necessary to check_free_sector after erasing ??
 304  */
 305 int NFTL_formatblock(struct NFTLrecord *nftl, int block)
 306 {
 307         size_t retlen;
 308         unsigned int nb_erases, erase_mark;
 309         struct nftl_uci1 uci;
 310         struct erase_info *instr = &nftl->instr;
 311         struct mtd_info *mtd = nftl->mbd.mtd;
 312
 313         /* Read the Unit Control Information #1 for Wear-Leveling */
 314         if (nftl_read_oob(mtd, block * nftl->EraseSize + SECTORSIZE + 8,
 315                           8, &retlen, (char *)&uci) < 0)
 316                 goto default_uci1;
 317
 318         erase_mark = le16_to_cpu ((uci.EraseMark | uci.EraseMark1));
 319         if (erase_mark != ERASE_MARK) {
 320         default_uci1:
 321                 uci.EraseMark = cpu_to_le16(ERASE_MARK);
 322                 uci.EraseMark1 = cpu_to_le16(ERASE_MARK);
 323                 uci.WearInfo = cpu_to_le32(0);
 324         }
 325
 326         memset(instr, 0, sizeof(struct erase_info));
 327
 328         /* XXX: use async erase interface, XXX: test return code */
 329         instr->addr = block * nftl->EraseSize;
 330         instr->len = nftl->EraseSize;
 331         if (mtd_erase(mtd, instr)) {
 332                 printk("Error while formatting block %d\n", block);
 333                 goto fail;
 334         }
 335
 336         /* increase and write Wear-Leveling info */
 337         nb_erases = le32_to_cpu(uci.WearInfo);
 338         nb_erases++;
 339
 340         /* wrap (almost impossible with current flash) or free block */
 341         if (nb_erases == 0)
 342                 nb_erases = 1;
 343
 344         /* check the "freeness" of Erase Unit before updating metadata
 345          * FixMe:  is this check really necessary ? since we have check the
 346          *         return code after the erase operation.
 347          */
 348         if (check_free_sectors(nftl, instr->addr, nftl->EraseSize, 1) != 0)
 349                 goto fail;
 350
 351         uci.WearInfo = le32_to_cpu(nb_erases);
 352         if (nftl_write_oob(mtd, block * nftl->EraseSize + SECTORSIZE +
 353                            8, 8, &retlen, (char *)&uci) < 0)
 354                 goto fail;
 355         return 0;
 356 fail:
 357         /* could not format, update the bad block table (caller is responsible
 358            for setting the ReplUnitTable to BLOCK_RESERVED on failure) */
 359         mtd_block_markbad(nftl->mbd.mtd, instr->addr);
 360         return -1;
 361 }
 362
 363 /* check_sectors_in_chain: Check that each sector of a Virtual Unit Chain is correct.
 364  *      Mark as 'IGNORE' each incorrect sector. This check is only done if the chain
 365  *      was being folded when NFTL was interrupted.
 366  *
 367  *      The check_free_sectors in this function is necessary. There is a possible
 368  *      situation that after writing the Data area, the Block Control Information is
 369  *      not updated according (due to power failure or something) which leaves the block
 370  *      in an inconsistent state. So we have to check if a block is really FREE in this
 371  *      case. */
 372 static void check_sectors_in_chain(struct NFTLrecord *nftl, unsigned int first_block)
 373 {
 374         struct mtd_info *mtd = nftl->mbd.mtd;
 375         unsigned int block, i, status;
 376         struct nftl_bci bci;
 377         int sectors_per_block;
 378         size_t retlen;
 379
 380         sectors_per_block = nftl->EraseSize / SECTORSIZE;
 381         block = first_block;
 382         for (;;) {
 383                 for (i = 0; i < sectors_per_block; i++) {
 384                         if (nftl_read_oob(mtd,
 385                                           block * nftl->EraseSize + i * SECTORSIZE,
 386                                           8, &retlen, (char *)&bci) < 0)
 387                                 status = SECTOR_IGNORE;
 388                         else
 389                                 status = bci.Status | bci.Status1;
 390
 391                         switch(status) {
 392                         case SECTOR_FREE:
 393                                 /* verify that the sector is really free. If not, mark
 394                                    as ignore */
 395                                 if (memcmpb(&bci, 0xff, 8) != 0 ||
 396                                     check_free_sectors(nftl, block * nftl->EraseSize + i * SECTORSIZE,
 397                                                        SECTORSIZE, 0) != 0) {
 398                                         printk("Incorrect free sector %d in block %d: "
 399                                                "marking it as ignored\n",
 400                                                i, block);
 401
 402                                         /* sector not free actually : mark it as SECTOR_IGNORE  */
 403                                         bci.Status = SECTOR_IGNORE;
 404                                         bci.Status1 = SECTOR_IGNORE;
 405                                         nftl_write_oob(mtd, block *
 406                                                        nftl->EraseSize +
 407                                                        i * SECTORSIZE, 8,
 408                                                        &retlen, (char *)&bci);
 409                                 }
 410                                 break;
 411                         default:
 412                                 break;
 413                         }
 414                 }
 415
 416                 /* proceed to next Erase Unit on the chain */
 417                 block = nftl->ReplUnitTable[block];
 418                 if (!(block == BLOCK_NIL || block < nftl->nb_blocks))
 419                         printk("incorrect ReplUnitTable[] : %d\n", block);
 420                 if (block == BLOCK_NIL || block >= nftl->nb_blocks)
 421                         break;
 422         }
 423 }
 424
 425 /* calc_chain_length: Walk through a Virtual Unit Chain and estimate chain length */
 426 static int calc_chain_length(struct NFTLrecord *nftl, unsigned int first_block)
 427 {
 428         unsigned int length = 0, block = first_block;
 429
 430         for (;;) {
 431                 length++;
 432                 /* avoid infinite loops, although this is guaranteed not to
 433                    happen because of the previous checks */
 434                 if (length >= nftl->nb_blocks) {
 435                         printk("nftl: length too long %d !\n", length);
 436                         break;
 437                 }
 438
 439                 block = nftl->ReplUnitTable[block];
 440                 if (!(block == BLOCK_NIL || block < nftl->nb_blocks))
 441                         printk("incorrect ReplUnitTable[] : %d\n", block);
 442                 if (block == BLOCK_NIL || block >= nftl->nb_blocks)
 443                         break;
 444         }
 445         return length;
 446 }
 447
 448 /* format_chain: Format an invalid Virtual Unit chain. It frees all the Erase Units in a
 449  *      Virtual Unit Chain, i.e. all the units are disconnected.
 450  *
 451  *      It is not strictly correct to begin from the first block of the chain because
 452  *      if we stop the code, we may see again a valid chain if there was a first_block
 453  *      flag in a block inside it. But is it really a problem ?
 454  *
 455  * FixMe: Figure out what the last statement means. What if power failure when we are
 456  *      in the for (;;) loop formatting blocks ??
 457  */
 458 static void format_chain(struct NFTLrecord *nftl, unsigned int first_block)
 459 {
 460         unsigned int block = first_block, block1;
 461
 462         printk("Formatting chain at block %d\n", first_block);
 463
 464         for (;;) {
 465                 block1 = nftl->ReplUnitTable[block];
 466
 467                 printk("Formatting block %d\n", block);
 468                 if (NFTL_formatblock(nftl, block) < 0) {
 469                         /* cannot format !!!! Mark it as Bad Unit */
 470                         nftl->ReplUnitTable[block] = BLOCK_RESERVED;
 471                 } else {
 472                         nftl->ReplUnitTable[block] = BLOCK_FREE;
 473                 }
 474
 475                 /* goto next block on the chain */
 476                 block = block1;
 477
 478                 if (!(block == BLOCK_NIL || block < nftl->nb_blocks))
 479                         printk("incorrect ReplUnitTable[] : %d\n", block);
 480                 if (block == BLOCK_NIL || block >= nftl->nb_blocks)
 481                         break;
 482         }
 483 }
 484
 485 /* check_and_mark_free_block: Verify that a block is free in the NFTL sense (valid erase mark) or
 486  *      totally free (only 0xff).
 487  *
 488  * Definition: Free Erase Unit -- A properly erased/formatted Free Erase Unit should have meet the
 489  *      following criteria:
 490  *      1. */
 491 static int check_and_mark_free_block(struct NFTLrecord *nftl, int block)
 492 {
 493         struct mtd_info *mtd = nftl->mbd.mtd;
 494         struct nftl_uci1 h1;
 495         unsigned int erase_mark;
 496         size_t retlen;
 497
 498         /* check erase mark. */
 499         if (nftl_read_oob(mtd, block * nftl->EraseSize + SECTORSIZE + 8, 8,
 500                           &retlen, (char *)&h1) < 0)
 501                 return -1;
 502
 503         erase_mark = le16_to_cpu ((h1.EraseMark | h1.EraseMark1));
 504         if (erase_mark != ERASE_MARK) {
 505                 /* if no erase mark, the block must be totally free. This is
 506                    possible in two cases : empty filesystem or interrupted erase (very unlikely) */
 507                 if (check_free_sectors (nftl, block * nftl->EraseSize, nftl->EraseSize, 1) != 0)
 508                         return -1;
 509
 510                 /* free block : write erase mark */
 511                 h1.EraseMark = cpu_to_le16(ERASE_MARK);
 512                 h1.EraseMark1 = cpu_to_le16(ERASE_MARK);
 513                 h1.WearInfo = cpu_to_le32(0);
 514                 if (nftl_write_oob(mtd,
 515                                    block * nftl->EraseSize + SECTORSIZE + 8, 8,
 516                                    &retlen, (char *)&h1) < 0)
 517                         return -1;
 518         } else {
 519 #if 0
 520                 /* if erase mark present, need to skip it when doing check */
 521                 for (i = 0; i < nftl->EraseSize; i += SECTORSIZE) {
 522                         /* check free sector */
 523                         if (check_free_sectors (nftl, block * nftl->EraseSize + i,
 524                                                 SECTORSIZE, 0) != 0)
 525                                 return -1;
 526
 527                         if (nftl_read_oob(mtd, block * nftl->EraseSize + i,
 528                                           16, &retlen, buf) < 0)
 529                                 return -1;
 530                         if (i == SECTORSIZE) {
 531                                 /* skip erase mark */
 532                                 if (memcmpb(buf, 0xff, 8))
 533                                         return -1;
 534                         } else {
 535                                 if (memcmpb(buf, 0xff, 16))
 536                                         return -1;
 537                         }
 538                 }
 539 #endif
 540         }
 541
 542         return 0;
 543 }
 544
 545 /* get_fold_mark: Read fold mark from Unit Control Information #2, we use FOLD_MARK_IN_PROGRESS
 546  *      to indicate that we are in the progression of a Virtual Unit Chain folding. If the UCI #2
 547  *      is FOLD_MARK_IN_PROGRESS when mounting the NFTL, the (previous) folding process is interrupted
 548  *      for some reason. A clean up/check of the VUC is necessary in this case.
 549  *
 550  * WARNING: return 0 if read error
 551  */
 552 static int get_fold_mark(struct NFTLrecord *nftl, unsigned int block)
 553 {
 554         struct mtd_info *mtd = nftl->mbd.mtd;
 555         struct nftl_uci2 uci;
 556         size_t retlen;
 557
 558         if (nftl_read_oob(mtd, block * nftl->EraseSize + 2 * SECTORSIZE + 8,
 559                           8, &retlen, (char *)&uci) < 0)
 560                 return 0;
 561
 562         return le16_to_cpu((uci.FoldMark | uci.FoldMark1));
 563 }
 564
 565 int NFTL_mount(struct NFTLrecord *s)
 566 {
 567         int i;
 568         unsigned int first_logical_block, logical_block, rep_block, erase_mark;
 569         unsigned int block, first_block, is_first_block;
 570         int chain_length, do_format_chain;
 571         struct nftl_uci0 h0;
 572         struct nftl_uci1 h1;
 573         struct mtd_info *mtd = s->mbd.mtd;
 574         size_t retlen;
 575
 576         /* search for NFTL MediaHeader and Spare NFTL Media Header */
 577         if (find_boot_record(s) < 0) {
 578                 printk("Could not find valid boot record\n");
 579                 return -1;
 580         }
 581
 582         /* init the logical to physical table */
 583         for (i = 0; i < s->nb_blocks; i++) {
 584                 s->EUNtable[i] = BLOCK_NIL;
 585         }
 586
 587         /* first pass : explore each block chain */
 588         first_logical_block = 0;
 589         for (first_block = 0; first_block < s->nb_blocks; first_block++) {
 590                 /* if the block was not already explored, we can look at it */
 591                 if (s->ReplUnitTable[first_block] == BLOCK_NOTEXPLORED) {
 592                         block = first_block;
 593                         chain_length = 0;
 594                         do_format_chain = 0;
 595
 596                         for (;;) {
 597                                 /* read the block header. If error, we format the chain */
 598                                 if (nftl_read_oob(mtd,
 599                                                   block * s->EraseSize + 8, 8,
 600                                                   &retlen, (char *)&h0) < 0 ||
 601                                     nftl_read_oob(mtd,
 602                                                   block * s->EraseSize +
 603                                                   SECTORSIZE + 8, 8,
 604                                                   &retlen, (char *)&h1) < 0) {
 605                                         s->ReplUnitTable[block] = BLOCK_NIL;
 606                                         do_format_chain = 1;
 607                                         break;
 608                                 }
 609
 610                                 logical_block = le16_to_cpu ((h0.VirtUnitNum | h0.SpareVirtUnitNum));
 611                                 rep_block = le16_to_cpu ((h0.ReplUnitNum | h0.SpareReplUnitNum));
 612                                 erase_mark = le16_to_cpu ((h1.EraseMark | h1.EraseMark1));
 613
 614                                 is_first_block = !(logical_block >> 15);
 615                                 logical_block = logical_block & 0x7fff;
 616
 617                                 /* invalid/free block test */
 618                                 if (erase_mark != ERASE_MARK || logical_block >= s->nb_blocks) {
 619                                         if (chain_length == 0) {
 620                                                 /* if not currently in a chain, we can handle it safely */
 621                                                 if (check_and_mark_free_block(s, block) < 0) {
 622                                                         /* not really free: format it */
 623                                                         printk("Formatting block %d\n", block);
 624                                                         if (NFTL_formatblock(s, block) < 0) {
 625                                                                 /* could not format: reserve the block */
 626                                                                 s->ReplUnitTable[block] = BLOCK_RESERVED;
 627                                                         } else {
 628                                                                 s->ReplUnitTable[block] = BLOCK_FREE;
 629                                                         }
 630                                                 } else {
 631                                                         /* free block: mark it */
 632                                                         s->ReplUnitTable[block] = BLOCK_FREE;
 633                                                 }
 634                                                 /* directly examine the next block. */
 635                                                 goto examine_ReplUnitTable;
 636                                         } else {
 637                                                 /* the block was in a chain : this is bad. We
 638                                                    must format all the chain */
 639                                                 printk("Block %d: free but referenced in chain %d\n",
 640                                                        block, first_block);
 641                                                 s->ReplUnitTable[block] = BLOCK_NIL;
 642                                                 do_format_chain = 1;
 643                                                 break;
 644                                         }
 645                                 }
 646
 647                                 /* we accept only first blocks here */
 648                                 if (chain_length == 0) {
 649                                         /* this block is not the first block in chain :
 650                                            ignore it, it will be included in a chain
 651                                            later, or marked as not explored */
 652                                         if (!is_first_block)
 653                                                 goto examine_ReplUnitTable;
 654                                         first_logical_block = logical_block;
 655                                 } else {
 656                                         if (logical_block != first_logical_block) {
 657                                                 printk("Block %d: incorrect logical block: %d expected: %d\n",
 658                                                        block, logical_block, first_logical_block);
 659                                                 /* the chain is incorrect : we must format it,
 660                                                    but we need to read it completely */
 661                                                 do_format_chain = 1;
 662                                         }
 663                                         if (is_first_block) {
 664                                                 /* we accept that a block is marked as first
 665                                                    block while being last block in a chain
 666                                                    only if the chain is being folded */
 667                                                 if (get_fold_mark(s, block) != FOLD_MARK_IN_PROGRESS ||
 668                                                     rep_block != 0xffff) {
 669                                                         printk("Block %d: incorrectly marked as first block in chain\n",
 670                                                                block);
 671                                                         /* the chain is incorrect : we must format it,
 672                                                            but we need to read it completely */
 673                                                         do_format_chain = 1;
 674                                                 } else {
 675                                                         printk("Block %d: folding in progress - ignoring first block flag\n",
 676                                                                block);
 677                                                 }
 678                                         }
 679                                 }
 680                                 chain_length++;
 681                                 if (rep_block == 0xffff) {
 682                                         /* no more blocks after */
 683                                         s->ReplUnitTable[block] = BLOCK_NIL;
 684                                         break;
 685                                 } else if (rep_block >= s->nb_blocks) {
 686                                         printk("Block %d: referencing invalid block %d\n",
 687                                                block, rep_block);
 688                                         do_format_chain = 1;
 689                                         s->ReplUnitTable[block] = BLOCK_NIL;
 690                                         break;
 691                                 } else if (s->ReplUnitTable[rep_block] != BLOCK_NOTEXPLORED) {
 692                                         /* same problem as previous 'is_first_block' test:
 693                                            we accept that the last block of a chain has
 694                                            the first_block flag set if folding is in
 695                                            progress. We handle here the case where the
 696                                            last block appeared first */
 697                                         if (s->ReplUnitTable[rep_block] == BLOCK_NIL &&
 698                                             s->EUNtable[first_logical_block] == rep_block &&
 699                                             get_fold_mark(s, first_block) == FOLD_MARK_IN_PROGRESS) {
 700                                                 /* EUNtable[] will be set after */
 701                                                 printk("Block %d: folding in progress - ignoring first block flag\n",
 702                                                        rep_block);
 703                                                 s->ReplUnitTable[block] = rep_block;
 704                                                 s->EUNtable[first_logical_block] = BLOCK_NIL;
 705                                         } else {
 706                                                 printk("Block %d: referencing block %d already in another chain\n",
 707                                                        block, rep_block);
 708                                                 /* XXX: should handle correctly fold in progress chains */
 709                                                 do_format_chain = 1;
 710                                                 s->ReplUnitTable[block] = BLOCK_NIL;
 711                                         }
 712                                         break;
 713                                 } else {
 714                                         /* this is OK */
 715                                         s->ReplUnitTable[block] = rep_block;
 716                                         block = rep_block;
 717                                 }
 718                         }
 719
 720                         /* the chain was completely explored. Now we can decide
 721                            what to do with it */
 722                         if (do_format_chain) {
 723                                 /* invalid chain : format it */
 724                                 format_chain(s, first_block);
 725                         } else {
 726                                 unsigned int first_block1, chain_to_format, chain_length1;
 727                                 int fold_mark;
 728
 729                                 /* valid chain : get foldmark */
 730                                 fold_mark = get_fold_mark(s, first_block);
 731                                 if (fold_mark == 0) {
 732                                         /* cannot get foldmark : format the chain */
 733                                         printk("Could read foldmark at block %d\n", first_block);
 734                                         format_chain(s, first_block);
 735                                 } else {
 736                                         if (fold_mark == FOLD_MARK_IN_PROGRESS)
 737                                                 check_sectors_in_chain(s, first_block);
 738
 739                                         /* now handle the case where we find two chains at the
 740                                            same virtual address : we select the longer one,
 741                                            because the shorter one is the one which was being
 742                                            folded if the folding was not done in place */
 743                                         first_block1 = s->EUNtable[first_logical_block];
 744                                         if (first_block1 != BLOCK_NIL) {
 745                                                 /* XXX: what to do if same length ? */
 746                                                 chain_length1 = calc_chain_length(s, first_block1);
 747                                                 printk("Two chains at blocks %d (len=%d) and %d (len=%d)\n",
 748                                                        first_block1, chain_length1, first_block, chain_length);
 749
 750                                                 if (chain_length >= chain_length1) {
 751                                                         chain_to_format = first_block1;
 752                                                         s->EUNtable[first_logical_block] = first_block;
 753                                                 } else {
 754                                                         chain_to_format = first_block;
 755                                                 }
 756                                                 format_chain(s, chain_to_format);
 757                                         } else {
 758                                                 s->EUNtable[first_logical_block] = first_block;
 759                                         }
 760                                 }
 761                         }
 762                 }
 763         examine_ReplUnitTable:;
 764         }
 765
 766         /* second pass to format unreferenced blocks  and init free block count */
 767         s->numfreeEUNs = 0;
 768         s->LastFreeEUN = le16_to_cpu(s->MediaHdr.FirstPhysicalEUN);
 769
 770         for (block = 0; block < s->nb_blocks; block++) {
 771                 if (s->ReplUnitTable[block] == BLOCK_NOTEXPLORED) {
 772                         printk("Unreferenced block %d, formatting it\n", block);
 773                         if (NFTL_formatblock(s, block) < 0)
 774                                 s->ReplUnitTable[block] = BLOCK_RESERVED;
 775                         else
 776                                 s->ReplUnitTable[block] = BLOCK_FREE;
 777                 }
 778                 if (s->ReplUnitTable[block] == BLOCK_FREE) {
 779                         s->numfreeEUNs++;
 780                         s->LastFreeEUN = block;
 781                 }
 782         }
 783
 784         return 0;
 785 }