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/rawnand.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                 ret = nftl_read_oob(mtd, block * nftl->EraseSize +
  93                                          SECTORSIZE + 8, 8, &retlen,
  94                                          (char *)&h1);
  95                 if (ret < 0) {
  96                         printk(KERN_WARNING "ANAND header found at 0x%x in mtd%d, but OOB data read failed (err %d)\n",
  97                                block * nftl->EraseSize, nftl->mbd.mtd->index, ret);
  98                         continue;
  99                 }
 100
 101 #if 0 /* Some people seem to have devices without ECC or erase marks
 102          on the Media Header blocks. There are enough other sanity
 103          checks in here that we can probably do without it.
 104       */
 105                 if (le16_to_cpu(h1.EraseMark | h1.EraseMark1) != ERASE_MARK) {
 106                         printk(KERN_NOTICE "ANAND header found at 0x%x in mtd%d, but erase mark not present (0x%04x,0x%04x instead)\n",
 107                                block * nftl->EraseSize, nftl->mbd.mtd->index,
 108                                le16_to_cpu(h1.EraseMark), le16_to_cpu(h1.EraseMark1));
 109                         continue;
 110                 }
 111
 112                 /* Finally reread to check ECC */
 113                 ret = mtd->read(mtd, block * nftl->EraseSize, SECTORSIZE,
 114                                 &retlen, buf);
 115                 if (ret < 0) {
 116                         printk(KERN_NOTICE "ANAND header found at 0x%x in mtd%d, but ECC read failed (err %d)\n",
 117                                block * nftl->EraseSize, nftl->mbd.mtd->index, ret);
 118                         continue;
 119                 }
 120
 121                 /* Paranoia. Check the ANAND header is still there after the ECC read */
 122                 if (memcmp(buf, "ANAND", 6)) {
 123                         printk(KERN_NOTICE "ANAND header found at 0x%x in mtd%d, but went away on reread!\n",
 124                                block * nftl->EraseSize, nftl->mbd.mtd->index);
 125                         printk(KERN_NOTICE "New data are: %6ph\n", buf);
 126                         continue;
 127                 }
 128 #endif
 129                 /* OK, we like it. */
 130
 131                 if (boot_record_count) {
 132                         /* We've already processed one. So we just check if
 133                            this one is the same as the first one we found */
 134                         if (memcmp(mh, buf, sizeof(struct NFTLMediaHeader))) {
 135                                 printk(KERN_NOTICE "NFTL Media Headers at 0x%x and 0x%x disagree.\n",
 136                                        nftl->MediaUnit * nftl->EraseSize, block * nftl->EraseSize);
 137                                 /* if (debug) Print both side by side */
 138                                 if (boot_record_count < 2) {
 139                                         /* We haven't yet seen two real ones */
 140                                         return -1;
 141                                 }
 142                                 continue;
 143                         }
 144                         if (boot_record_count == 1)
 145                                 nftl->SpareMediaUnit = block;
 146
 147                         /* Mark this boot record (NFTL MediaHeader) block as reserved */
 148                         nftl->ReplUnitTable[block] = BLOCK_RESERVED;
 149
 150
 151                         boot_record_count++;
 152                         continue;
 153                 }
 154
 155                 /* This is the first we've seen. Copy the media header structure into place */
 156                 memcpy(mh, buf, sizeof(struct NFTLMediaHeader));
 157
 158                 /* Do some sanity checks on it */
 159 #if 0
 160 The new DiskOnChip driver scans the MediaHeader itself, and presents a virtual
 161 erasesize based on UnitSizeFactor.  So the erasesize we read from the mtd
 162 device is already correct.
 163                 if (mh->UnitSizeFactor == 0) {
 164                         printk(KERN_NOTICE "NFTL: UnitSizeFactor 0x00 detected. This violates the spec but we think we know what it means...\n");
 165                 } else if (mh->UnitSizeFactor < 0xfc) {
 166                         printk(KERN_NOTICE "Sorry, we don't support UnitSizeFactor 0x%02x\n",
 167                                mh->UnitSizeFactor);
 168                         return -1;
 169                 } else if (mh->UnitSizeFactor != 0xff) {
 170                         printk(KERN_NOTICE "WARNING: Support for NFTL with UnitSizeFactor 0x%02x is experimental\n",
 171                                mh->UnitSizeFactor);
 172                         nftl->EraseSize = nftl->mbd.mtd->erasesize << (0xff - mh->UnitSizeFactor);
 173                         nftl->nb_blocks = (u32)nftl->mbd.mtd->size / nftl->EraseSize;
 174                 }
 175 #endif
 176                 nftl->nb_boot_blocks = le16_to_cpu(mh->FirstPhysicalEUN);
 177                 if ((nftl->nb_boot_blocks + 2) >= nftl->nb_blocks) {
 178                         printk(KERN_NOTICE "NFTL Media Header sanity check failed:\n");
 179                         printk(KERN_NOTICE "nb_boot_blocks (%d) + 2 > nb_blocks (%d)\n",
 180                                nftl->nb_boot_blocks, nftl->nb_blocks);
 181                         return -1;
 182                 }
 183
 184                 nftl->numvunits = le32_to_cpu(mh->FormattedSize) / nftl->EraseSize;
 185                 if (nftl->numvunits > (nftl->nb_blocks - nftl->nb_boot_blocks - 2)) {
 186                         printk(KERN_NOTICE "NFTL Media Header sanity check failed:\n");
 187                         printk(KERN_NOTICE "numvunits (%d) > nb_blocks (%d) - nb_boot_blocks(%d) - 2\n",
 188                                nftl->numvunits, nftl->nb_blocks, nftl->nb_boot_blocks);
 189                         return -1;
 190                 }
 191
 192                 nftl->mbd.size  = nftl->numvunits * (nftl->EraseSize / SECTORSIZE);
 193
 194                 /* If we're not using the last sectors in the device for some reason,
 195                    reduce nb_blocks accordingly so we forget they're there */
 196                 nftl->nb_blocks = le16_to_cpu(mh->NumEraseUnits) + le16_to_cpu(mh->FirstPhysicalEUN);
 197
 198                 /* XXX: will be suppressed */
 199                 nftl->lastEUN = nftl->nb_blocks - 1;
 200
 201                 /* memory alloc */
 202                 nftl->EUNtable = kmalloc_array(nftl->nb_blocks, sizeof(u16),
 203                                                GFP_KERNEL);
 204                 if (!nftl->EUNtable) {
 205                         printk(KERN_NOTICE "NFTL: allocation of EUNtable failed\n");
 206                         return -ENOMEM;
 207                 }
 208
 209                 nftl->ReplUnitTable = kmalloc_array(nftl->nb_blocks,
 210                                                     sizeof(u16),
 211                                                     GFP_KERNEL);
 212                 if (!nftl->ReplUnitTable) {
 213                         kfree(nftl->EUNtable);
 214                         printk(KERN_NOTICE "NFTL: allocation of ReplUnitTable failed\n");
 215                         return -ENOMEM;
 216                 }
 217
 218                 /* mark the bios blocks (blocks before NFTL MediaHeader) as reserved */
 219                 for (i = 0; i < nftl->nb_boot_blocks; i++)
 220                         nftl->ReplUnitTable[i] = BLOCK_RESERVED;
 221                 /* mark all remaining blocks as potentially containing data */
 222                 for (; i < nftl->nb_blocks; i++) {
 223                         nftl->ReplUnitTable[i] = BLOCK_NOTEXPLORED;
 224                 }
 225
 226                 /* Mark this boot record (NFTL MediaHeader) block as reserved */
 227                 nftl->ReplUnitTable[block] = BLOCK_RESERVED;
 228
 229                 /* read the Bad Erase Unit Table and modify ReplUnitTable[] accordingly */
 230                 for (i = 0; i < nftl->nb_blocks; i++) {
 231 #if 0
 232 The new DiskOnChip driver already scanned the bad block table.  Just query it.
 233                         if ((i & (SECTORSIZE - 1)) == 0) {
 234                                 /* read one sector for every SECTORSIZE of blocks */
 235                                 ret = mtd->read(nftl->mbd.mtd,
 236                                                 block * nftl->EraseSize + i +
 237                                                 SECTORSIZE, SECTORSIZE,
 238                                                 &retlen, buf);
 239                                 if (ret < 0) {
 240                                         printk(KERN_NOTICE "Read of bad sector table failed (err %d)\n",
 241                                                ret);
 242                                         kfree(nftl->ReplUnitTable);
 243                                         kfree(nftl->EUNtable);
 244                                         return -1;
 245                                 }
 246                         }
 247                         /* mark the Bad Erase Unit as RESERVED in ReplUnitTable */
 248                         if (buf[i & (SECTORSIZE - 1)] != 0xff)
 249                                 nftl->ReplUnitTable[i] = BLOCK_RESERVED;
 250 #endif
 251                         if (mtd_block_isbad(nftl->mbd.mtd,
 252                                             i * nftl->EraseSize))
 253                                 nftl->ReplUnitTable[i] = BLOCK_RESERVED;
 254                 }
 255
 256                 nftl->MediaUnit = block;
 257                 boot_record_count++;
 258
 259         } /* foreach (block) */
 260
 261         return boot_record_count?0:-1;
 262 }
 263
 264 static int memcmpb(void *a, int c, int n)
 265 {
 266         int i;
 267         for (i = 0; i < n; i++) {
 268                 if (c != ((unsigned char *)a)[i])
 269                         return 1;
 270         }
 271         return 0;
 272 }
 273
 274 /* check_free_sector: check if a free sector is actually FREE, i.e. All 0xff in data and oob area */
 275 static int check_free_sectors(struct NFTLrecord *nftl, unsigned int address, int len,
 276                               int check_oob)
 277 {
 278         struct mtd_info *mtd = nftl->mbd.mtd;
 279         size_t retlen;
 280         int i, ret;
 281         u8 *buf;
 282
 283         buf = kmalloc(SECTORSIZE + mtd->oobsize, GFP_KERNEL);
 284         if (!buf)
 285                 return -1;
 286
 287         ret = -1;
 288         for (i = 0; i < len; i += SECTORSIZE) {
 289                 if (mtd_read(mtd, address, SECTORSIZE, &retlen, buf))
 290                         goto out;
 291                 if (memcmpb(buf, 0xff, SECTORSIZE) != 0)
 292                         goto out;
 293
 294                 if (check_oob) {
 295                         if(nftl_read_oob(mtd, address, mtd->oobsize,
 296                                          &retlen, &buf[SECTORSIZE]) < 0)
 297                                 goto out;
 298                         if (memcmpb(buf + SECTORSIZE, 0xff, mtd->oobsize) != 0)
 299                                 goto out;
 300                 }
 301                 address += SECTORSIZE;
 302         }
 303
 304         ret = 0;
 305
 306 out:
 307         kfree(buf);
 308         return ret;
 309 }
 310
 311 /* NFTL_format: format a Erase Unit by erasing ALL Erase Zones in the Erase Unit and
 312  *              Update NFTL metadata. Each erase operation is checked with check_free_sectors
 313  *
 314  * Return: 0 when succeed, -1 on error.
 315  *
 316  *  ToDo: 1. Is it necessary to check_free_sector after erasing ??
 317  */
 318 int NFTL_formatblock(struct NFTLrecord *nftl, int block)
 319 {
 320         size_t retlen;
 321         unsigned int nb_erases, erase_mark;
 322         struct nftl_uci1 uci;
 323         struct erase_info *instr = &nftl->instr;
 324         struct mtd_info *mtd = nftl->mbd.mtd;
 325
 326         /* Read the Unit Control Information #1 for Wear-Leveling */
 327         if (nftl_read_oob(mtd, block * nftl->EraseSize + SECTORSIZE + 8,
 328                           8, &retlen, (char *)&uci) < 0)
 329                 goto default_uci1;
 330
 331         erase_mark = le16_to_cpu ((uci.EraseMark | uci.EraseMark1));
 332         if (erase_mark != ERASE_MARK) {
 333         default_uci1:
 334                 uci.EraseMark = cpu_to_le16(ERASE_MARK);
 335                 uci.EraseMark1 = cpu_to_le16(ERASE_MARK);
 336                 uci.WearInfo = cpu_to_le32(0);
 337         }
 338
 339         memset(instr, 0, sizeof(struct erase_info));
 340
 341         /* XXX: use async erase interface, XXX: test return code */
 342         instr->addr = block * nftl->EraseSize;
 343         instr->len = nftl->EraseSize;
 344         if (mtd_erase(mtd, instr)) {
 345                 printk("Error while formatting block %d\n", block);
 346                 goto fail;
 347         }
 348
 349         /* increase and write Wear-Leveling info */
 350         nb_erases = le32_to_cpu(uci.WearInfo);
 351         nb_erases++;
 352
 353         /* wrap (almost impossible with current flash) or free block */
 354         if (nb_erases == 0)
 355                 nb_erases = 1;
 356
 357         /* check the "freeness" of Erase Unit before updating metadata
 358          * FixMe:  is this check really necessary ? since we have check the
 359          *         return code after the erase operation.
 360          */
 361         if (check_free_sectors(nftl, instr->addr, nftl->EraseSize, 1) != 0)
 362                 goto fail;
 363
 364         uci.WearInfo = le32_to_cpu(nb_erases);
 365         if (nftl_write_oob(mtd, block * nftl->EraseSize + SECTORSIZE +
 366                            8, 8, &retlen, (char *)&uci) < 0)
 367                 goto fail;
 368         return 0;
 369 fail:
 370         /* could not format, update the bad block table (caller is responsible
 371            for setting the ReplUnitTable to BLOCK_RESERVED on failure) */
 372         mtd_block_markbad(nftl->mbd.mtd, instr->addr);
 373         return -1;
 374 }
 375
 376 /* check_sectors_in_chain: Check that each sector of a Virtual Unit Chain is correct.
 377  *      Mark as 'IGNORE' each incorrect sector. This check is only done if the chain
 378  *      was being folded when NFTL was interrupted.
 379  *
 380  *      The check_free_sectors in this function is necessary. There is a possible
 381  *      situation that after writing the Data area, the Block Control Information is
 382  *      not updated according (due to power failure or something) which leaves the block
 383  *      in an inconsistent state. So we have to check if a block is really FREE in this
 384  *      case. */
 385 static void check_sectors_in_chain(struct NFTLrecord *nftl, unsigned int first_block)
 386 {
 387         struct mtd_info *mtd = nftl->mbd.mtd;
 388         unsigned int block, i, status;
 389         struct nftl_bci bci;
 390         int sectors_per_block;
 391         size_t retlen;
 392
 393         sectors_per_block = nftl->EraseSize / SECTORSIZE;
 394         block = first_block;
 395         for (;;) {
 396                 for (i = 0; i < sectors_per_block; i++) {
 397                         if (nftl_read_oob(mtd,
 398                                           block * nftl->EraseSize + i * SECTORSIZE,
 399                                           8, &retlen, (char *)&bci) < 0)
 400                                 status = SECTOR_IGNORE;
 401                         else
 402                                 status = bci.Status | bci.Status1;
 403
 404                         switch(status) {
 405                         case SECTOR_FREE:
 406                                 /* verify that the sector is really free. If not, mark
 407                                    as ignore */
 408                                 if (memcmpb(&bci, 0xff, 8) != 0 ||
 409                                     check_free_sectors(nftl, block * nftl->EraseSize + i * SECTORSIZE,
 410                                                        SECTORSIZE, 0) != 0) {
 411                                         printk("Incorrect free sector %d in block %d: "
 412                                                "marking it as ignored\n",
 413                                                i, block);
 414
 415                                         /* sector not free actually : mark it as SECTOR_IGNORE  */
 416                                         bci.Status = SECTOR_IGNORE;
 417                                         bci.Status1 = SECTOR_IGNORE;
 418                                         nftl_write_oob(mtd, block *
 419                                                        nftl->EraseSize +
 420                                                        i * SECTORSIZE, 8,
 421                                                        &retlen, (char *)&bci);
 422                                 }
 423                                 break;
 424                         default:
 425                                 break;
 426                         }
 427                 }
 428
 429                 /* proceed to next Erase Unit on the chain */
 430                 block = nftl->ReplUnitTable[block];
 431                 if (!(block == BLOCK_NIL || block < nftl->nb_blocks))
 432                         printk("incorrect ReplUnitTable[] : %d\n", block);
 433                 if (block == BLOCK_NIL || block >= nftl->nb_blocks)
 434                         break;
 435         }
 436 }
 437
 438 /* calc_chain_length: Walk through a Virtual Unit Chain and estimate chain length */
 439 static int calc_chain_length(struct NFTLrecord *nftl, unsigned int first_block)
 440 {
 441         unsigned int length = 0, block = first_block;
 442
 443         for (;;) {
 444                 length++;
 445                 /* avoid infinite loops, although this is guaranteed not to
 446                    happen because of the previous checks */
 447                 if (length >= nftl->nb_blocks) {
 448                         printk("nftl: length too long %d !\n", length);
 449                         break;
 450                 }
 451
 452                 block = nftl->ReplUnitTable[block];
 453                 if (!(block == BLOCK_NIL || block < nftl->nb_blocks))
 454                         printk("incorrect ReplUnitTable[] : %d\n", block);
 455                 if (block == BLOCK_NIL || block >= nftl->nb_blocks)
 456                         break;
 457         }
 458         return length;
 459 }
 460
 461 /* format_chain: Format an invalid Virtual Unit chain. It frees all the Erase Units in a
 462  *      Virtual Unit Chain, i.e. all the units are disconnected.
 463  *
 464  *      It is not strictly correct to begin from the first block of the chain because
 465  *      if we stop the code, we may see again a valid chain if there was a first_block
 466  *      flag in a block inside it. But is it really a problem ?
 467  *
 468  * FixMe: Figure out what the last statement means. What if power failure when we are
 469  *      in the for (;;) loop formatting blocks ??
 470  */
 471 static void format_chain(struct NFTLrecord *nftl, unsigned int first_block)
 472 {
 473         unsigned int block = first_block, block1;
 474
 475         printk("Formatting chain at block %d\n", first_block);
 476
 477         for (;;) {
 478                 block1 = nftl->ReplUnitTable[block];
 479
 480                 printk("Formatting block %d\n", block);
 481                 if (NFTL_formatblock(nftl, block) < 0) {
 482                         /* cannot format !!!! Mark it as Bad Unit */
 483                         nftl->ReplUnitTable[block] = BLOCK_RESERVED;
 484                 } else {
 485                         nftl->ReplUnitTable[block] = BLOCK_FREE;
 486                 }
 487
 488                 /* goto next block on the chain */
 489                 block = block1;
 490
 491                 if (!(block == BLOCK_NIL || block < nftl->nb_blocks))
 492                         printk("incorrect ReplUnitTable[] : %d\n", block);
 493                 if (block == BLOCK_NIL || block >= nftl->nb_blocks)
 494                         break;
 495         }
 496 }
 497
 498 /* check_and_mark_free_block: Verify that a block is free in the NFTL sense (valid erase mark) or
 499  *      totally free (only 0xff).
 500  *
 501  * Definition: Free Erase Unit -- A properly erased/formatted Free Erase Unit should have meet the
 502  *      following criteria:
 503  *      1. */
 504 static int check_and_mark_free_block(struct NFTLrecord *nftl, int block)
 505 {
 506         struct mtd_info *mtd = nftl->mbd.mtd;
 507         struct nftl_uci1 h1;
 508         unsigned int erase_mark;
 509         size_t retlen;
 510
 511         /* check erase mark. */
 512         if (nftl_read_oob(mtd, block * nftl->EraseSize + SECTORSIZE + 8, 8,
 513                           &retlen, (char *)&h1) < 0)
 514                 return -1;
 515
 516         erase_mark = le16_to_cpu ((h1.EraseMark | h1.EraseMark1));
 517         if (erase_mark != ERASE_MARK) {
 518                 /* if no erase mark, the block must be totally free. This is
 519                    possible in two cases : empty filesystem or interrupted erase (very unlikely) */
 520                 if (check_free_sectors (nftl, block * nftl->EraseSize, nftl->EraseSize, 1) != 0)
 521                         return -1;
 522
 523                 /* free block : write erase mark */
 524                 h1.EraseMark = cpu_to_le16(ERASE_MARK);
 525                 h1.EraseMark1 = cpu_to_le16(ERASE_MARK);
 526                 h1.WearInfo = cpu_to_le32(0);
 527                 if (nftl_write_oob(mtd,
 528                                    block * nftl->EraseSize + SECTORSIZE + 8, 8,
 529                                    &retlen, (char *)&h1) < 0)
 530                         return -1;
 531         } else {
 532 #if 0
 533                 /* if erase mark present, need to skip it when doing check */
 534                 for (i = 0; i < nftl->EraseSize; i += SECTORSIZE) {
 535                         /* check free sector */
 536                         if (check_free_sectors (nftl, block * nftl->EraseSize + i,
 537                                                 SECTORSIZE, 0) != 0)
 538                                 return -1;
 539
 540                         if (nftl_read_oob(mtd, block * nftl->EraseSize + i,
 541                                           16, &retlen, buf) < 0)
 542                                 return -1;
 543                         if (i == SECTORSIZE) {
 544                                 /* skip erase mark */
 545                                 if (memcmpb(buf, 0xff, 8))
 546                                         return -1;
 547                         } else {
 548                                 if (memcmpb(buf, 0xff, 16))
 549                                         return -1;
 550                         }
 551                 }
 552 #endif
 553         }
 554
 555         return 0;
 556 }
 557
 558 /* get_fold_mark: Read fold mark from Unit Control Information #2, we use FOLD_MARK_IN_PROGRESS
 559  *      to indicate that we are in the progression of a Virtual Unit Chain folding. If the UCI #2
 560  *      is FOLD_MARK_IN_PROGRESS when mounting the NFTL, the (previous) folding process is interrupted
 561  *      for some reason. A clean up/check of the VUC is necessary in this case.
 562  *
 563  * WARNING: return 0 if read error
 564  */
 565 static int get_fold_mark(struct NFTLrecord *nftl, unsigned int block)
 566 {
 567         struct mtd_info *mtd = nftl->mbd.mtd;
 568         struct nftl_uci2 uci;
 569         size_t retlen;
 570
 571         if (nftl_read_oob(mtd, block * nftl->EraseSize + 2 * SECTORSIZE + 8,
 572                           8, &retlen, (char *)&uci) < 0)
 573                 return 0;
 574
 575         return le16_to_cpu((uci.FoldMark | uci.FoldMark1));
 576 }
 577
 578 int NFTL_mount(struct NFTLrecord *s)
 579 {
 580         int i;
 581         unsigned int first_logical_block, logical_block, rep_block, erase_mark;
 582         unsigned int block, first_block, is_first_block;
 583         int chain_length, do_format_chain;
 584         struct nftl_uci0 h0;
 585         struct nftl_uci1 h1;
 586         struct mtd_info *mtd = s->mbd.mtd;
 587         size_t retlen;
 588
 589         /* search for NFTL MediaHeader and Spare NFTL Media Header */
 590         if (find_boot_record(s) < 0) {
 591                 printk("Could not find valid boot record\n");
 592                 return -1;
 593         }
 594
 595         /* init the logical to physical table */
 596         for (i = 0; i < s->nb_blocks; i++) {
 597                 s->EUNtable[i] = BLOCK_NIL;
 598         }
 599
 600         /* first pass : explore each block chain */
 601         first_logical_block = 0;
 602         for (first_block = 0; first_block < s->nb_blocks; first_block++) {
 603                 /* if the block was not already explored, we can look at it */
 604                 if (s->ReplUnitTable[first_block] == BLOCK_NOTEXPLORED) {
 605                         block = first_block;
 606                         chain_length = 0;
 607                         do_format_chain = 0;
 608
 609                         for (;;) {
 610                                 /* read the block header. If error, we format the chain */
 611                                 if (nftl_read_oob(mtd,
 612                                                   block * s->EraseSize + 8, 8,
 613                                                   &retlen, (char *)&h0) < 0 ||
 614                                     nftl_read_oob(mtd,
 615                                                   block * s->EraseSize +
 616                                                   SECTORSIZE + 8, 8,
 617                                                   &retlen, (char *)&h1) < 0) {
 618                                         s->ReplUnitTable[block] = BLOCK_NIL;
 619                                         do_format_chain = 1;
 620                                         break;
 621                                 }
 622
 623                                 logical_block = le16_to_cpu ((h0.VirtUnitNum | h0.SpareVirtUnitNum));
 624                                 rep_block = le16_to_cpu ((h0.ReplUnitNum | h0.SpareReplUnitNum));
 625                                 erase_mark = le16_to_cpu ((h1.EraseMark | h1.EraseMark1));
 626
 627                                 is_first_block = !(logical_block >> 15);
 628                                 logical_block = logical_block & 0x7fff;
 629
 630                                 /* invalid/free block test */
 631                                 if (erase_mark != ERASE_MARK || logical_block >= s->nb_blocks) {
 632                                         if (chain_length == 0) {
 633                                                 /* if not currently in a chain, we can handle it safely */
 634                                                 if (check_and_mark_free_block(s, block) < 0) {
 635                                                         /* not really free: format it */
 636                                                         printk("Formatting block %d\n", block);
 637                                                         if (NFTL_formatblock(s, block) < 0) {
 638                                                                 /* could not format: reserve the block */
 639                                                                 s->ReplUnitTable[block] = BLOCK_RESERVED;
 640                                                         } else {
 641                                                                 s->ReplUnitTable[block] = BLOCK_FREE;
 642                                                         }
 643                                                 } else {
 644                                                         /* free block: mark it */
 645                                                         s->ReplUnitTable[block] = BLOCK_FREE;
 646                                                 }
 647                                                 /* directly examine the next block. */
 648                                                 goto examine_ReplUnitTable;
 649                                         } else {
 650                                                 /* the block was in a chain : this is bad. We
 651                                                    must format all the chain */
 652                                                 printk("Block %d: free but referenced in chain %d\n",
 653                                                        block, first_block);
 654                                                 s->ReplUnitTable[block] = BLOCK_NIL;
 655                                                 do_format_chain = 1;
 656                                                 break;
 657                                         }
 658                                 }
 659
 660                                 /* we accept only first blocks here */
 661                                 if (chain_length == 0) {
 662                                         /* this block is not the first block in chain :
 663                                            ignore it, it will be included in a chain
 664                                            later, or marked as not explored */
 665                                         if (!is_first_block)
 666                                                 goto examine_ReplUnitTable;
 667                                         first_logical_block = logical_block;
 668                                 } else {
 669                                         if (logical_block != first_logical_block) {
 670                                                 printk("Block %d: incorrect logical block: %d expected: %d\n",
 671                                                        block, logical_block, first_logical_block);
 672                                                 /* the chain is incorrect : we must format it,
 673                                                    but we need to read it completely */
 674                                                 do_format_chain = 1;
 675                                         }
 676                                         if (is_first_block) {
 677                                                 /* we accept that a block is marked as first
 678                                                    block while being last block in a chain
 679                                                    only if the chain is being folded */
 680                                                 if (get_fold_mark(s, block) != FOLD_MARK_IN_PROGRESS ||
 681                                                     rep_block != 0xffff) {
 682                                                         printk("Block %d: incorrectly marked as first block in chain\n",
 683                                                                block);
 684                                                         /* the chain is incorrect : we must format it,
 685                                                            but we need to read it completely */
 686                                                         do_format_chain = 1;
 687                                                 } else {
 688                                                         printk("Block %d: folding in progress - ignoring first block flag\n",
 689                                                                block);
 690                                                 }
 691                                         }
 692                                 }
 693                                 chain_length++;
 694                                 if (rep_block == 0xffff) {
 695                                         /* no more blocks after */
 696                                         s->ReplUnitTable[block] = BLOCK_NIL;
 697                                         break;
 698                                 } else if (rep_block >= s->nb_blocks) {
 699                                         printk("Block %d: referencing invalid block %d\n",
 700                                                block, rep_block);
 701                                         do_format_chain = 1;
 702                                         s->ReplUnitTable[block] = BLOCK_NIL;
 703                                         break;
 704                                 } else if (s->ReplUnitTable[rep_block] != BLOCK_NOTEXPLORED) {
 705                                         /* same problem as previous 'is_first_block' test:
 706                                            we accept that the last block of a chain has
 707                                            the first_block flag set if folding is in
 708                                            progress. We handle here the case where the
 709                                            last block appeared first */
 710                                         if (s->ReplUnitTable[rep_block] == BLOCK_NIL &&
 711                                             s->EUNtable[first_logical_block] == rep_block &&
 712                                             get_fold_mark(s, first_block) == FOLD_MARK_IN_PROGRESS) {
 713                                                 /* EUNtable[] will be set after */
 714                                                 printk("Block %d: folding in progress - ignoring first block flag\n",
 715                                                        rep_block);
 716                                                 s->ReplUnitTable[block] = rep_block;
 717                                                 s->EUNtable[first_logical_block] = BLOCK_NIL;
 718                                         } else {
 719                                                 printk("Block %d: referencing block %d already in another chain\n",
 720                                                        block, rep_block);
 721                                                 /* XXX: should handle correctly fold in progress chains */
 722                                                 do_format_chain = 1;
 723                                                 s->ReplUnitTable[block] = BLOCK_NIL;
 724                                         }
 725                                         break;
 726                                 } else {
 727                                         /* this is OK */
 728                                         s->ReplUnitTable[block] = rep_block;
 729                                         block = rep_block;
 730                                 }
 731                         }
 732
 733                         /* the chain was completely explored. Now we can decide
 734                            what to do with it */
 735                         if (do_format_chain) {
 736                                 /* invalid chain : format it */
 737                                 format_chain(s, first_block);
 738                         } else {
 739                                 unsigned int first_block1, chain_to_format, chain_length1;
 740                                 int fold_mark;
 741
 742                                 /* valid chain : get foldmark */
 743                                 fold_mark = get_fold_mark(s, first_block);
 744                                 if (fold_mark == 0) {
 745                                         /* cannot get foldmark : format the chain */
 746                                         printk("Could read foldmark at block %d\n", first_block);
 747                                         format_chain(s, first_block);
 748                                 } else {
 749                                         if (fold_mark == FOLD_MARK_IN_PROGRESS)
 750                                                 check_sectors_in_chain(s, first_block);
 751
 752                                         /* now handle the case where we find two chains at the
 753                                            same virtual address : we select the longer one,
 754                                            because the shorter one is the one which was being
 755                                            folded if the folding was not done in place */
 756                                         first_block1 = s->EUNtable[first_logical_block];
 757                                         if (first_block1 != BLOCK_NIL) {
 758                                                 /* XXX: what to do if same length ? */
 759                                                 chain_length1 = calc_chain_length(s, first_block1);
 760                                                 printk("Two chains at blocks %d (len=%d) and %d (len=%d)\n",
 761                                                        first_block1, chain_length1, first_block, chain_length);
 762
 763                                                 if (chain_length >= chain_length1) {
 764                                                         chain_to_format = first_block1;
 765                                                         s->EUNtable[first_logical_block] = first_block;
 766                                                 } else {
 767                                                         chain_to_format = first_block;
 768                                                 }
 769                                                 format_chain(s, chain_to_format);
 770                                         } else {
 771                                                 s->EUNtable[first_logical_block] = first_block;
 772                                         }
 773                                 }
 774                         }
 775                 }
 776         examine_ReplUnitTable:;
 777         }
 778
 779         /* second pass to format unreferenced blocks  and init free block count */
 780         s->numfreeEUNs = 0;
 781         s->LastFreeEUN = le16_to_cpu(s->MediaHdr.FirstPhysicalEUN);
 782
 783         for (block = 0; block < s->nb_blocks; block++) {
 784                 if (s->ReplUnitTable[block] == BLOCK_NOTEXPLORED) {
 785                         printk("Unreferenced block %d, formatting it\n", block);
 786                         if (NFTL_formatblock(s, block) < 0)
 787                                 s->ReplUnitTable[block] = BLOCK_RESERVED;
 788                         else
 789                                 s->ReplUnitTable[block] = BLOCK_FREE;
 790                 }
 791                 if (s->ReplUnitTable[block] == BLOCK_FREE) {
 792                         s->numfreeEUNs++;
 793                         s->LastFreeEUN = block;
 794                 }
 795         }
 796
 797         return 0;
 798 }