drivers/mtd/nftlmount.c

   1 /*
   2  * NFTL mount code with extensive checks
   3  *
   4  * Author: Fabrice Bellard (fabrice.bellard@netgem.com)
   5  * Copyright © 2000 Netgem S.A.
   6  * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  */
  22
  23 #include <linux/kernel.h>
  24 #include <asm/errno.h>
  25 #include <linux/delay.h>
  26 #include <linux/slab.h>
  27 #include <linux/mtd/mtd.h>
  28 #include <linux/mtd/nand.h>
  29 #include <linux/mtd/nftl.h>
  30
  31 #define SECTORSIZE 512
  32
  33 /* find_boot_record: Find the NFTL Media Header and its Spare copy which contains the
  34  *      various device information of the NFTL partition and Bad Unit Table. Update
  35  *      the ReplUnitTable[] table according to the Bad Unit Table. ReplUnitTable[]
  36  *      is used for management of Erase Unit in other routines in nftl.c and nftlmount.c
  37  */
  38 static int find_boot_record(struct NFTLrecord *nftl)
  39 {
  40         struct nftl_uci1 h1;
  41         unsigned int block, boot_record_count = 0;
  42         size_t retlen;
  43         u8 buf[SECTORSIZE];
  44         struct NFTLMediaHeader *mh = &nftl->MediaHdr;
  45         struct mtd_info *mtd = nftl->mbd.mtd;
  46         unsigned int i;
  47
  48         /* Assume logical EraseSize == physical erasesize for starting the scan.
  49            We'll sort it out later if we find a MediaHeader which says otherwise */
  50         /* Actually, we won't.  The new DiskOnChip driver has already scanned
  51            the MediaHeader and adjusted the virtual erasesize it presents in
  52            the mtd device accordingly.  We could even get rid of
  53            nftl->EraseSize if there were any point in doing so. */
  54         nftl->EraseSize = nftl->mbd.mtd->erasesize;
  55         nftl->nb_blocks = (u32)nftl->mbd.mtd->size / nftl->EraseSize;
  56
  57         nftl->MediaUnit = BLOCK_NIL;
  58         nftl->SpareMediaUnit = BLOCK_NIL;
  59
  60         /* search for a valid boot record */
  61         for (block = 0; block < nftl->nb_blocks; block++) {
  62                 int ret;
  63
  64                 /* Check for ANAND header first. Then can whinge if it's found but later
  65                    checks fail */
  66                 ret = mtd_read(mtd, block * nftl->EraseSize, SECTORSIZE,
  67                                &retlen, buf);
  68                 /* We ignore ret in case the ECC of the MediaHeader is invalid
  69                    (which is apparently acceptable) */
  70                 if (retlen != SECTORSIZE) {
  71                         static int warncount = 5;
  72
  73                         if (warncount) {
  74                                 printk(KERN_WARNING "Block read at 0x%x of mtd%d failed: %d\n",
  75                                        block * nftl->EraseSize, nftl->mbd.mtd->index, ret);
  76                                 if (!--warncount)
  77                                         printk(KERN_WARNING "Further failures for this block will not be printed\n");
  78                         }
  79                         continue;
  80                 }
  81
  82                 if (retlen < 6 || memcmp(buf, "ANAND", 6)) {
  83                         /* ANAND\0 not found. Continue */
  84 #if 0
  85                         printk(KERN_DEBUG "ANAND header not found at 0x%x in mtd%d\n",
  86                                block * nftl->EraseSize, nftl->mbd.mtd->index);
  87 #endif
  88                         continue;
  89                 }
  90
  91                 /* To be safer with BIOS, also use erase mark as discriminant */
  92                 if ((ret = nftl_read_oob(mtd, block * nftl->EraseSize +
  93                                          SECTORSIZE + 8, 8, &retlen,
  94                                          (char *)&h1) < 0)) {
  95                         printk(KERN_WARNING "ANAND header found at 0x%x in mtd%d, but OOB data read failed (err %d)\n",
  96                                block * nftl->EraseSize, nftl->mbd.mtd->index, ret);
  97                         continue;
  98                 }
  99
 100 #if 0 /* Some people seem to have devices without ECC or erase marks
 101          on the Media Header blocks. There are enough other sanity
 102          checks in here that we can probably do without it.
 103       */
 104                 if (le16_to_cpu(h1.EraseMark | h1.EraseMark1) != ERASE_MARK) {
 105                         printk(KERN_NOTICE "ANAND header found at 0x%x in mtd%d, but erase mark not present (0x%04x,0x%04x instead)\n",
 106                                block * nftl->EraseSize, nftl->mbd.mtd->index,
 107                                le16_to_cpu(h1.EraseMark), le16_to_cpu(h1.EraseMark1));
 108                         continue;
 109                 }
 110
 111                 /* Finally reread to check ECC */
 112                 if ((ret = mtd->read(mtd, block * nftl->EraseSize, SECTORSIZE,
 113                                      &retlen, buf) < 0)) {
 114                         printk(KERN_NOTICE "ANAND header found at 0x%x in mtd%d, but ECC read failed (err %d)\n",
 115                                block * nftl->EraseSize, nftl->mbd.mtd->index, ret);
 116                         continue;
 117                 }
 118
 119                 /* Paranoia. Check the ANAND header is still there after the ECC read */
 120                 if (memcmp(buf, "ANAND", 6)) {
 121                         printk(KERN_NOTICE "ANAND header found at 0x%x in mtd%d, but went away on reread!\n",
 122                                block * nftl->EraseSize, nftl->mbd.mtd->index);
 123                         printk(KERN_NOTICE "New data are: %02x %02x %02x %02x %02x %02x\n",
 124                                buf[0], buf[1], buf[2], buf[3], buf[4], buf[5]);
 125                         continue;
 126                 }
 127 #endif
 128                 /* OK, we like it. */
 129
 130                 if (boot_record_count) {
 131                         /* We've already processed one. So we just check if
 132                            this one is the same as the first one we found */
 133                         if (memcmp(mh, buf, sizeof(struct NFTLMediaHeader))) {
 134                                 printk(KERN_NOTICE "NFTL Media Headers at 0x%x and 0x%x disagree.\n",
 135                                        nftl->MediaUnit * nftl->EraseSize, block * nftl->EraseSize);
 136                                 /* if (debug) Print both side by side */
 137                                 if (boot_record_count < 2) {
 138                                         /* We haven't yet seen two real ones */
 139                                         return -1;
 140                                 }
 141                                 continue;
 142                         }
 143                         if (boot_record_count == 1)
 144                                 nftl->SpareMediaUnit = block;
 145
 146                         /* Mark this boot record (NFTL MediaHeader) block as reserved */
 147                         nftl->ReplUnitTable[block] = BLOCK_RESERVED;
 148
 149
 150                         boot_record_count++;
 151                         continue;
 152                 }
 153
 154                 /* This is the first we've seen. Copy the media header structure into place */
 155                 memcpy(mh, buf, sizeof(struct NFTLMediaHeader));
 156
 157                 /* Do some sanity checks on it */
 158 #if 0
 159 The new DiskOnChip driver scans the MediaHeader itself, and presents a virtual
 160 erasesize based on UnitSizeFactor.  So the erasesize we read from the mtd
 161 device is already correct.
 162                 if (mh->UnitSizeFactor == 0) {
 163                         printk(KERN_NOTICE "NFTL: UnitSizeFactor 0x00 detected. This violates the spec but we think we know what it means...\n");
 164                 } else if (mh->UnitSizeFactor < 0xfc) {
 165                         printk(KERN_NOTICE "Sorry, we don't support UnitSizeFactor 0x%02x\n",
 166                                mh->UnitSizeFactor);
 167                         return -1;
 168                 } else if (mh->UnitSizeFactor != 0xff) {
 169                         printk(KERN_NOTICE "WARNING: Support for NFTL with UnitSizeFactor 0x%02x is experimental\n",
 170                                mh->UnitSizeFactor);
 171                         nftl->EraseSize = nftl->mbd.mtd->erasesize << (0xff - mh->UnitSizeFactor);
 172                         nftl->nb_blocks = (u32)nftl->mbd.mtd->size / nftl->EraseSize;
 173                 }
 174 #endif
 175                 nftl->nb_boot_blocks = le16_to_cpu(mh->FirstPhysicalEUN);
 176                 if ((nftl->nb_boot_blocks + 2) >= nftl->nb_blocks) {
 177                         printk(KERN_NOTICE "NFTL Media Header sanity check failed:\n");
 178                         printk(KERN_NOTICE "nb_boot_blocks (%d) + 2 > nb_blocks (%d)\n",
 179                                nftl->nb_boot_blocks, nftl->nb_blocks);
 180                         return -1;
 181                 }
 182
 183                 nftl->numvunits = le32_to_cpu(mh->FormattedSize) / nftl->EraseSize;
 184                 if (nftl->numvunits > (nftl->nb_blocks - nftl->nb_boot_blocks - 2)) {
 185                         printk(KERN_NOTICE "NFTL Media Header sanity check failed:\n");
 186                         printk(KERN_NOTICE "numvunits (%d) > nb_blocks (%d) - nb_boot_blocks(%d) - 2\n",
 187                                nftl->numvunits, nftl->nb_blocks, nftl->nb_boot_blocks);
 188                         return -1;
 189                 }
 190
 191                 nftl->mbd.size  = nftl->numvunits * (nftl->EraseSize / SECTORSIZE);
 192
 193                 /* If we're not using the last sectors in the device for some reason,
 194                    reduce nb_blocks accordingly so we forget they're there */
 195                 nftl->nb_blocks = le16_to_cpu(mh->NumEraseUnits) + le16_to_cpu(mh->FirstPhysicalEUN);
 196
 197                 /* XXX: will be suppressed */
 198                 nftl->lastEUN = nftl->nb_blocks - 1;
 199
 200                 /* memory alloc */
 201                 nftl->EUNtable = kmalloc(nftl->nb_blocks * sizeof(u16), GFP_KERNEL);
 202                 if (!nftl->EUNtable) {
 203                         printk(KERN_NOTICE "NFTL: allocation of EUNtable failed\n");
 204                         return -ENOMEM;
 205                 }
 206
 207                 nftl->ReplUnitTable = kmalloc(nftl->nb_blocks * sizeof(u16), GFP_KERNEL);
 208                 if (!nftl->ReplUnitTable) {
 209                         kfree(nftl->EUNtable);
 210                         printk(KERN_NOTICE "NFTL: allocation of ReplUnitTable failed\n");
 211                         return -ENOMEM;
 212                 }
 213
 214                 /* mark the bios blocks (blocks before NFTL MediaHeader) as reserved */
 215                 for (i = 0; i < nftl->nb_boot_blocks; i++)
 216                         nftl->ReplUnitTable[i] = BLOCK_RESERVED;
 217                 /* mark all remaining blocks as potentially containing data */
 218                 for (; i < nftl->nb_blocks; i++) {
 219                         nftl->ReplUnitTable[i] = BLOCK_NOTEXPLORED;
 220                 }
 221
 222                 /* Mark this boot record (NFTL MediaHeader) block as reserved */
 223                 nftl->ReplUnitTable[block] = BLOCK_RESERVED;
 224
 225                 /* read the Bad Erase Unit Table and modify ReplUnitTable[] accordingly */
 226                 for (i = 0; i < nftl->nb_blocks; i++) {
 227 #if 0
 228 The new DiskOnChip driver already scanned the bad block table.  Just query it.
 229                         if ((i & (SECTORSIZE - 1)) == 0) {
 230                                 /* read one sector for every SECTORSIZE of blocks */
 231                                 if ((ret = mtd->read(nftl->mbd.mtd, block * nftl->EraseSize +
 232                                                      i + SECTORSIZE, SECTORSIZE, &retlen,
 233                                                      buf)) < 0) {
 234                                         printk(KERN_NOTICE "Read of bad sector table failed (err %d)\n",
 235                                                ret);
 236                                         kfree(nftl->ReplUnitTable);
 237                                         kfree(nftl->EUNtable);
 238                                         return -1;
 239                                 }
 240                         }
 241                         /* mark the Bad Erase Unit as RESERVED in ReplUnitTable */
 242                         if (buf[i & (SECTORSIZE - 1)] != 0xff)
 243                                 nftl->ReplUnitTable[i] = BLOCK_RESERVED;
 244 #endif
 245                         if (mtd_block_isbad(nftl->mbd.mtd,
 246                                             i * nftl->EraseSize))
 247                                 nftl->ReplUnitTable[i] = BLOCK_RESERVED;
 248                 }
 249
 250                 nftl->MediaUnit = block;
 251                 boot_record_count++;
 252
 253         } /* foreach (block) */
 254
 255         return boot_record_count?0:-1;
 256 }
 257
 258 static int memcmpb(void *a, int c, int n)
 259 {
 260         int i;
 261         for (i = 0; i < n; i++) {
 262                 if (c != ((unsigned char *)a)[i])
 263                         return 1;
 264         }
 265         return 0;
 266 }
 267
 268 /* check_free_sector: check if a free sector is actually FREE, i.e. All 0xff in data and oob area */
 269 static int check_free_sectors(struct NFTLrecord *nftl, unsigned int address, int len,
 270                               int check_oob)
 271 {
 272         u8 buf[SECTORSIZE + nftl->mbd.mtd->oobsize];
 273         struct mtd_info *mtd = nftl->mbd.mtd;
 274         size_t retlen;
 275         int i;
 276
 277         for (i = 0; i < len; i += SECTORSIZE) {
 278                 if (mtd_read(mtd, address, SECTORSIZE, &retlen, buf))
 279                         return -1;
 280                 if (memcmpb(buf, 0xff, SECTORSIZE) != 0)
 281                         return -1;
 282
 283                 if (check_oob) {
 284                         if(nftl_read_oob(mtd, address, mtd->oobsize,
 285                                          &retlen, &buf[SECTORSIZE]) < 0)
 286                                 return -1;
 287                         if (memcmpb(buf + SECTORSIZE, 0xff, mtd->oobsize) != 0)
 288                                 return -1;
 289                 }
 290                 address += SECTORSIZE;
 291         }
 292
 293         return 0;
 294 }
 295
 296 /* NFTL_format: format a Erase Unit by erasing ALL Erase Zones in the Erase Unit and
 297  *              Update NFTL metadata. Each erase operation is checked with check_free_sectors
 298  *
 299  * Return: 0 when succeed, -1 on error.
 300  *
 301  *  ToDo: 1. Is it necessary to check_free_sector after erasing ??
 302  */
 303 int NFTL_formatblock(struct NFTLrecord *nftl, int block)
 304 {
 305         size_t retlen;
 306         unsigned int nb_erases, erase_mark;
 307         struct nftl_uci1 uci;
 308         struct erase_info *instr = &nftl->instr;
 309         struct mtd_info *mtd = nftl->mbd.mtd;
 310
 311         /* Read the Unit Control Information #1 for Wear-Leveling */
 312         if (nftl_read_oob(mtd, block * nftl->EraseSize + SECTORSIZE + 8,
 313                           8, &retlen, (char *)&uci) < 0)
 314                 goto default_uci1;
 315
 316         erase_mark = le16_to_cpu ((uci.EraseMark | uci.EraseMark1));
 317         if (erase_mark != ERASE_MARK) {
 318         default_uci1:
 319                 uci.EraseMark = cpu_to_le16(ERASE_MARK);
 320                 uci.EraseMark1 = cpu_to_le16(ERASE_MARK);
 321                 uci.WearInfo = cpu_to_le32(0);
 322         }
 323
 324         memset(instr, 0, sizeof(struct erase_info));
 325
 326         /* XXX: use async erase interface, XXX: test return code */
 327         instr->mtd = nftl->mbd.mtd;
 328         instr->addr = block * nftl->EraseSize;
 329         instr->len = nftl->EraseSize;
 330         mtd_erase(mtd, instr);
 331
 332         if (instr->state == MTD_ERASE_FAILED) {
 333                 printk("Error while formatting block %d\n", block);
 334                 goto fail;
 335         }
 336
 337                 /* increase and write Wear-Leveling info */
 338                 nb_erases = le32_to_cpu(uci.WearInfo);
 339                 nb_erases++;
 340
 341                 /* wrap (almost impossible with current flash) or free block */
 342                 if (nb_erases == 0)
 343                         nb_erases = 1;
 344
 345                 /* check the "freeness" of Erase Unit before updating metadata
 346                  * FixMe:  is this check really necessary ? since we have check the
 347                  *         return code after the erase operation. */
 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, nb_erases, 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                                 nb_erases = le32_to_cpu (h1.WearInfo);
 613                                 erase_mark = le16_to_cpu ((h1.EraseMark | h1.EraseMark1));
 614
 615                                 is_first_block = !(logical_block >> 15);
 616                                 logical_block = logical_block & 0x7fff;
 617
 618                                 /* invalid/free block test */
 619                                 if (erase_mark != ERASE_MARK || logical_block >= s->nb_blocks) {
 620                                         if (chain_length == 0) {
 621                                                 /* if not currently in a chain, we can handle it safely */
 622                                                 if (check_and_mark_free_block(s, block) < 0) {
 623                                                         /* not really free: format it */
 624                                                         printk("Formatting block %d\n", block);
 625                                                         if (NFTL_formatblock(s, block) < 0) {
 626                                                                 /* could not format: reserve the block */
 627                                                                 s->ReplUnitTable[block] = BLOCK_RESERVED;
 628                                                         } else {
 629                                                                 s->ReplUnitTable[block] = BLOCK_FREE;
 630                                                         }
 631                                                 } else {
 632                                                         /* free block: mark it */
 633                                                         s->ReplUnitTable[block] = BLOCK_FREE;
 634                                                 }
 635                                                 /* directly examine the next block. */
 636                                                 goto examine_ReplUnitTable;
 637                                         } else {
 638                                                 /* the block was in a chain : this is bad. We
 639                                                    must format all the chain */
 640                                                 printk("Block %d: free but referenced in chain %d\n",
 641                                                        block, first_block);
 642                                                 s->ReplUnitTable[block] = BLOCK_NIL;
 643                                                 do_format_chain = 1;
 644                                                 break;
 645                                         }
 646                                 }
 647
 648                                 /* we accept only first blocks here */
 649                                 if (chain_length == 0) {
 650                                         /* this block is not the first block in chain :
 651                                            ignore it, it will be included in a chain
 652                                            later, or marked as not explored */
 653                                         if (!is_first_block)
 654                                                 goto examine_ReplUnitTable;
 655                                         first_logical_block = logical_block;
 656                                 } else {
 657                                         if (logical_block != first_logical_block) {
 658                                                 printk("Block %d: incorrect logical block: %d expected: %d\n",
 659                                                        block, logical_block, first_logical_block);
 660                                                 /* the chain is incorrect : we must format it,
 661                                                    but we need to read it completely */
 662                                                 do_format_chain = 1;
 663                                         }
 664                                         if (is_first_block) {
 665                                                 /* we accept that a block is marked as first
 666                                                    block while being last block in a chain
 667                                                    only if the chain is being folded */
 668                                                 if (get_fold_mark(s, block) != FOLD_MARK_IN_PROGRESS ||
 669                                                     rep_block != 0xffff) {
 670                                                         printk("Block %d: incorrectly marked as first block in chain\n",
 671                                                                block);
 672                                                         /* the chain is incorrect : we must format it,
 673                                                            but we need to read it completely */
 674                                                         do_format_chain = 1;
 675                                                 } else {
 676                                                         printk("Block %d: folding in progress - ignoring first block flag\n",
 677                                                                block);
 678                                                 }
 679                                         }
 680                                 }
 681                                 chain_length++;
 682                                 if (rep_block == 0xffff) {
 683                                         /* no more blocks after */
 684                                         s->ReplUnitTable[block] = BLOCK_NIL;
 685                                         break;
 686                                 } else if (rep_block >= s->nb_blocks) {
 687                                         printk("Block %d: referencing invalid block %d\n",
 688                                                block, rep_block);
 689                                         do_format_chain = 1;
 690                                         s->ReplUnitTable[block] = BLOCK_NIL;
 691                                         break;
 692                                 } else if (s->ReplUnitTable[rep_block] != BLOCK_NOTEXPLORED) {
 693                                         /* same problem as previous 'is_first_block' test:
 694                                            we accept that the last block of a chain has
 695                                            the first_block flag set if folding is in
 696                                            progress. We handle here the case where the
 697                                            last block appeared first */
 698                                         if (s->ReplUnitTable[rep_block] == BLOCK_NIL &&
 699                                             s->EUNtable[first_logical_block] == rep_block &&
 700                                             get_fold_mark(s, first_block) == FOLD_MARK_IN_PROGRESS) {
 701                                                 /* EUNtable[] will be set after */
 702                                                 printk("Block %d: folding in progress - ignoring first block flag\n",
 703                                                        rep_block);
 704                                                 s->ReplUnitTable[block] = rep_block;
 705                                                 s->EUNtable[first_logical_block] = BLOCK_NIL;
 706                                         } else {
 707                                                 printk("Block %d: referencing block %d already in another chain\n",
 708                                                        block, rep_block);
 709                                                 /* XXX: should handle correctly fold in progress chains */
 710                                                 do_format_chain = 1;
 711                                                 s->ReplUnitTable[block] = BLOCK_NIL;
 712                                         }
 713                                         break;
 714                                 } else {
 715                                         /* this is OK */
 716                                         s->ReplUnitTable[block] = rep_block;
 717                                         block = rep_block;
 718                                 }
 719                         }
 720
 721                         /* the chain was completely explored. Now we can decide
 722                            what to do with it */
 723                         if (do_format_chain) {
 724                                 /* invalid chain : format it */
 725                                 format_chain(s, first_block);
 726                         } else {
 727                                 unsigned int first_block1, chain_to_format, chain_length1;
 728                                 int fold_mark;
 729
 730                                 /* valid chain : get foldmark */
 731                                 fold_mark = get_fold_mark(s, first_block);
 732                                 if (fold_mark == 0) {
 733                                         /* cannot get foldmark : format the chain */
 734                                         printk("Could read foldmark at block %d\n", first_block);
 735                                         format_chain(s, first_block);
 736                                 } else {
 737                                         if (fold_mark == FOLD_MARK_IN_PROGRESS)
 738                                                 check_sectors_in_chain(s, first_block);
 739
 740                                         /* now handle the case where we find two chains at the
 741                                            same virtual address : we select the longer one,
 742                                            because the shorter one is the one which was being
 743                                            folded if the folding was not done in place */
 744                                         first_block1 = s->EUNtable[first_logical_block];
 745                                         if (first_block1 != BLOCK_NIL) {
 746                                                 /* XXX: what to do if same length ? */
 747                                                 chain_length1 = calc_chain_length(s, first_block1);
 748                                                 printk("Two chains at blocks %d (len=%d) and %d (len=%d)\n",
 749                                                        first_block1, chain_length1, first_block, chain_length);
 750
 751                                                 if (chain_length >= chain_length1) {
 752                                                         chain_to_format = first_block1;
 753                                                         s->EUNtable[first_logical_block] = first_block;
 754                                                 } else {
 755                                                         chain_to_format = first_block;
 756                                                 }
 757                                                 format_chain(s, chain_to_format);
 758                                         } else {
 759                                                 s->EUNtable[first_logical_block] = first_block;
 760                                         }
 761                                 }
 762                         }
 763                 }
 764         examine_ReplUnitTable:;
 765         }
 766
 767         /* second pass to format unreferenced blocks  and init free block count */
 768         s->numfreeEUNs = 0;
 769         s->LastFreeEUN = le16_to_cpu(s->MediaHdr.FirstPhysicalEUN);
 770
 771         for (block = 0; block < s->nb_blocks; block++) {
 772                 if (s->ReplUnitTable[block] == BLOCK_NOTEXPLORED) {
 773                         printk("Unreferenced block %d, formatting it\n", block);
 774                         if (NFTL_formatblock(s, block) < 0)
 775                                 s->ReplUnitTable[block] = BLOCK_RESERVED;
 776                         else
 777                                 s->ReplUnitTable[block] = BLOCK_FREE;
 778                 }
 779                 if (s->ReplUnitTable[block] == BLOCK_FREE) {
 780                         s->numfreeEUNs++;
 781                         s->LastFreeEUN = block;
 782                 }
 783         }
 784
 785         return 0;
 786 }