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   1 /*
   2  * JFFS2 -- Journalling Flash File System, Version 2.
   3  *
   4  * Copyright (C) 2001-2003 Red Hat, Inc.
   5  *
   6  * Created by David Woodhouse <dwmw2@infradead.org>
   7  *
   8  * For licensing information, see the file 'LICENCE' in this directory.
   9  *
  10  * $Id: scan.c,v 1.116 2005/02/09 09:09:02 pavlov Exp $
  11  *
  12  */
  13 #include <linux/kernel.h>
  14 #include <linux/sched.h>
  15 #include <linux/slab.h>
  16 #include <linux/mtd/mtd.h>
  17 #include <linux/pagemap.h>
  18 #include <linux/crc32.h>
  19 #include <linux/compiler.h>
  20 #include "nodelist.h"
  21
  22 #define DEFAULT_EMPTY_SCAN_SIZE 1024
  23
  24 #define DIRTY_SPACE(x) do { typeof(x) _x = (x); \
  25                 c->free_size -= _x; c->dirty_size += _x; \
  26                 jeb->free_size -= _x ; jeb->dirty_size += _x; \
  27                 }while(0)
  28 #define USED_SPACE(x) do { typeof(x) _x = (x); \
  29                 c->free_size -= _x; c->used_size += _x; \
  30                 jeb->free_size -= _x ; jeb->used_size += _x; \
  31                 }while(0)
  32 #define UNCHECKED_SPACE(x) do { typeof(x) _x = (x); \
  33                 c->free_size -= _x; c->unchecked_size += _x; \
  34                 jeb->free_size -= _x ; jeb->unchecked_size += _x; \
  35                 }while(0)
  36
  37 #define noisy_printk(noise, args...) do { \
  38         if (*(noise)) { \
  39                 printk(KERN_NOTICE args); \
  40                  (*(noise))--; \
  41                  if (!(*(noise))) { \
  42                          printk(KERN_NOTICE "Further such events for this erase block will not be printed\n"); \
  43                  } \
  44         } \
  45 } while(0)
  46
  47 static uint32_t pseudo_random;
  48
  49 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  50                                   unsigned char *buf, uint32_t buf_size);
  51
  52 /* These helper functions _must_ increase ofs and also do the dirty/used space accounting.
  53  * Returning an error will abort the mount - bad checksums etc. should just mark the space
  54  * as dirty.
  55  */
  56 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  57                                  struct jffs2_raw_inode *ri, uint32_t ofs);
  58 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  59                                  struct jffs2_raw_dirent *rd, uint32_t ofs);
  60
  61 #define BLK_STATE_ALLFF         0
  62 #define BLK_STATE_CLEAN         1
  63 #define BLK_STATE_PARTDIRTY     2
  64 #define BLK_STATE_CLEANMARKER   3
  65 #define BLK_STATE_ALLDIRTY      4
  66 #define BLK_STATE_BADBLOCK      5
  67
  68 static inline int min_free(struct jffs2_sb_info *c)
  69 {
  70         uint32_t min = 2 * sizeof(struct jffs2_raw_inode);
  71 #if defined CONFIG_JFFS2_FS_NAND || defined CONFIG_JFFS2_FS_NOR_ECC
  72         if (!jffs2_can_mark_obsolete(c) && min < c->wbuf_pagesize)
  73                 return c->wbuf_pagesize;
  74 #endif
  75         return min;
  76
  77 }
  78
  79 static inline uint32_t EMPTY_SCAN_SIZE(uint32_t sector_size) {
  80         if (sector_size < DEFAULT_EMPTY_SCAN_SIZE)
  81                 return sector_size;
  82         else
  83                 return DEFAULT_EMPTY_SCAN_SIZE;
  84 }
  85
  86 int jffs2_scan_medium(struct jffs2_sb_info *c)
  87 {
  88         int i, ret;
  89         uint32_t empty_blocks = 0, bad_blocks = 0;
  90         unsigned char *flashbuf = NULL;
  91         uint32_t buf_size = 0;
  92 #ifndef __ECOS
  93         size_t pointlen;
  94
  95         if (c->mtd->point) {
  96                 ret = c->mtd->point (c->mtd, 0, c->mtd->size, &pointlen, &flashbuf);
  97                 if (!ret && pointlen < c->mtd->size) {
  98                         /* Don't muck about if it won't let us point to the whole flash */
  99                         D1(printk(KERN_DEBUG "MTD point returned len too short: 0x%zx\n", pointlen));
 100                         c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
 101                         flashbuf = NULL;
 102                 }
 103                 if (ret)
 104                         D1(printk(KERN_DEBUG "MTD point failed %d\n", ret));
 105         }
 106 #endif
 107         if (!flashbuf) {
 108                 /* For NAND it's quicker to read a whole eraseblock at a time,
 109                    apparently */
 110                 if (jffs2_cleanmarker_oob(c))
 111                         buf_size = c->sector_size;
 112                 else
 113                         buf_size = PAGE_SIZE;
 114
 115                 /* Respect kmalloc limitations */
 116                 if (buf_size > 128*1024)
 117                         buf_size = 128*1024;
 118
 119                 D1(printk(KERN_DEBUG "Allocating readbuf of %d bytes\n", buf_size));
 120                 flashbuf = kmalloc(buf_size, GFP_KERNEL);
 121                 if (!flashbuf)
 122                         return -ENOMEM;
 123         }
 124
 125         for (i=0; i<c->nr_blocks; i++) {
 126                 struct jffs2_eraseblock *jeb = &c->blocks[i];
 127
 128                 ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset), buf_size);
 129
 130                 if (ret < 0)
 131                         goto out;
 132
 133                 ACCT_PARANOIA_CHECK(jeb);
 134
 135                 /* Now decide which list to put it on */
 136                 switch(ret) {
 137                 case BLK_STATE_ALLFF:
 138                         /*
 139                          * Empty block.   Since we can't be sure it
 140                          * was entirely erased, we just queue it for erase
 141                          * again.  It will be marked as such when the erase
 142                          * is complete.  Meanwhile we still count it as empty
 143                          * for later checks.
 144                          */
 145                         empty_blocks++;
 146                         list_add(&jeb->list, &c->erase_pending_list);
 147                         c->nr_erasing_blocks++;
 148                         break;
 149
 150                 case BLK_STATE_CLEANMARKER:
 151                         /* Only a CLEANMARKER node is valid */
 152                         if (!jeb->dirty_size) {
 153                                 /* It's actually free */
 154                                 list_add(&jeb->list, &c->free_list);
 155                                 c->nr_free_blocks++;
 156                         } else {
 157                                 /* Dirt */
 158                                 D1(printk(KERN_DEBUG "Adding all-dirty block at 0x%08x to erase_pending_list\n", jeb->offset));
 159                                 list_add(&jeb->list, &c->erase_pending_list);
 160                                 c->nr_erasing_blocks++;
 161                         }
 162                         break;
 163
 164                 case BLK_STATE_CLEAN:
 165                         /* Full (or almost full) of clean data. Clean list */
 166                         list_add(&jeb->list, &c->clean_list);
 167                         break;
 168
 169                 case BLK_STATE_PARTDIRTY:
 170                         /* Some data, but not full. Dirty list. */
 171                         /* We want to remember the block with most free space
 172                            and stick it in the 'nextblock' position to start writing to it. */
 173                         if (jeb->free_size > min_free(c) &&
 174                             (!c->nextblock || c->nextblock->free_size < jeb->free_size)) {
 175                                 /* Better candidate for the next writes to go to */
 176                                 if (c->nextblock) {
 177                                         c->nextblock->dirty_size += c->nextblock->free_size + c->nextblock->wasted_size;
 178                                         c->dirty_size += c->nextblock->free_size + c->nextblock->wasted_size;
 179                                         c->free_size -= c->nextblock->free_size;
 180                                         c->wasted_size -= c->nextblock->wasted_size;
 181                                         c->nextblock->free_size = c->nextblock->wasted_size = 0;
 182                                         if (VERYDIRTY(c, c->nextblock->dirty_size)) {
 183                                                 list_add(&c->nextblock->list, &c->very_dirty_list);
 184                                         } else {
 185                                                 list_add(&c->nextblock->list, &c->dirty_list);
 186                                         }
 187                                 }
 188                                 c->nextblock = jeb;
 189                         } else {
 190                                 jeb->dirty_size += jeb->free_size + jeb->wasted_size;
 191                                 c->dirty_size += jeb->free_size + jeb->wasted_size;
 192                                 c->free_size -= jeb->free_size;
 193                                 c->wasted_size -= jeb->wasted_size;
 194                                 jeb->free_size = jeb->wasted_size = 0;
 195                                 if (VERYDIRTY(c, jeb->dirty_size)) {
 196                                         list_add(&jeb->list, &c->very_dirty_list);
 197                                 } else {
 198                                         list_add(&jeb->list, &c->dirty_list);
 199                                 }
 200                         }
 201                         break;
 202
 203                 case BLK_STATE_ALLDIRTY:
 204                         /* Nothing valid - not even a clean marker. Needs erasing. */
 205                         /* For now we just put it on the erasing list. We'll start the erases later */
 206                         D1(printk(KERN_NOTICE "JFFS2: Erase block at 0x%08x is not formatted. It will be erased\n", jeb->offset));
 207                         list_add(&jeb->list, &c->erase_pending_list);
 208                         c->nr_erasing_blocks++;
 209                         break;
 210
 211                 case BLK_STATE_BADBLOCK:
 212                         D1(printk(KERN_NOTICE "JFFS2: Block at 0x%08x is bad\n", jeb->offset));
 213                         list_add(&jeb->list, &c->bad_list);
 214                         c->bad_size += c->sector_size;
 215                         c->free_size -= c->sector_size;
 216                         bad_blocks++;
 217                         break;
 218                 default:
 219                         printk(KERN_WARNING "jffs2_scan_medium(): unknown block state\n");
 220                         BUG();
 221                 }
 222         }
 223
 224         /* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
 225         if (c->nextblock && (c->nextblock->dirty_size)) {
 226                 c->nextblock->wasted_size += c->nextblock->dirty_size;
 227                 c->wasted_size += c->nextblock->dirty_size;
 228                 c->dirty_size -= c->nextblock->dirty_size;
 229                 c->nextblock->dirty_size = 0;
 230         }
 231 #if defined CONFIG_JFFS2_FS_NAND || defined CONFIG_JFFS2_FS_NOR_ECC
 232         if (!jffs2_can_mark_obsolete(c) && c->nextblock && (c->nextblock->free_size & (c->wbuf_pagesize-1))) {
 233                 /* If we're going to start writing into a block which already
 234                    contains data, and the end of the data isn't page-aligned,
 235                    skip a little and align it. */
 236
 237                 uint32_t skip = c->nextblock->free_size & (c->wbuf_pagesize-1);
 238
 239                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): Skipping %d bytes in nextblock to ensure page alignment\n",
 240                           skip));
 241                 c->nextblock->wasted_size += skip;
 242                 c->wasted_size += skip;
 243
 244                 c->nextblock->free_size -= skip;
 245                 c->free_size -= skip;
 246         }
 247 #endif
 248         if (c->nr_erasing_blocks) {
 249                 if ( !c->used_size && ((c->nr_free_blocks+empty_blocks+bad_blocks)!= c->nr_blocks || bad_blocks == c->nr_blocks) ) {
 250                         printk(KERN_NOTICE "Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
 251                         printk(KERN_NOTICE "empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",empty_blocks,bad_blocks,c->nr_blocks);
 252                         ret = -EIO;
 253                         goto out;
 254                 }
 255                 jffs2_erase_pending_trigger(c);
 256         }
 257         ret = 0;
 258  out:
 259         if (buf_size)
 260                 kfree(flashbuf);
 261 #ifndef __ECOS
 262         else
 263                 c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
 264 #endif
 265         return ret;
 266 }
 267
 268 static int jffs2_fill_scan_buf (struct jffs2_sb_info *c, unsigned char *buf,
 269                                 uint32_t ofs, uint32_t len)
 270 {
 271         int ret;
 272         size_t retlen;
 273
 274         ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
 275         if (ret) {
 276                 D1(printk(KERN_WARNING "mtd->read(0x%x bytes from 0x%x) returned %d\n", len, ofs, ret));
 277                 return ret;
 278         }
 279         if (retlen < len) {
 280                 D1(printk(KERN_WARNING "Read at 0x%x gave only 0x%zx bytes\n", ofs, retlen));
 281                 return -EIO;
 282         }
 283         D2(printk(KERN_DEBUG "Read 0x%x bytes from 0x%08x into buf\n", len, ofs));
 284         D2(printk(KERN_DEBUG "000: %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x\n",
 285                   buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], buf[6], buf[7], buf[8], buf[9], buf[10], buf[11], buf[12], buf[13], buf[14], buf[15]));
 286         return 0;
 287 }
 288
 289 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 290                                   unsigned char *buf, uint32_t buf_size) {
 291         struct jffs2_unknown_node *node;
 292         struct jffs2_unknown_node crcnode;
 293         uint32_t ofs, prevofs;
 294         uint32_t hdr_crc, buf_ofs, buf_len;
 295         int err;
 296         int noise = 0;
 297 #ifdef CONFIG_JFFS2_FS_NAND
 298         int cleanmarkerfound = 0;
 299 #endif
 300
 301         ofs = jeb->offset;
 302         prevofs = jeb->offset - 1;
 303
 304         D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs));
 305
 306 #ifdef CONFIG_JFFS2_FS_NAND
 307         if (jffs2_cleanmarker_oob(c)) {
 308                 int ret = jffs2_check_nand_cleanmarker(c, jeb);
 309                 D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n",ret));
 310                 /* Even if it's not found, we still scan to see
 311                    if the block is empty. We use this information
 312                    to decide whether to erase it or not. */
 313                 switch (ret) {
 314                 case 0:         cleanmarkerfound = 1; break;
 315                 case 1:         break;
 316                 case 2:         return BLK_STATE_BADBLOCK;
 317                 case 3:         return BLK_STATE_ALLDIRTY; /* Block has failed to erase min. once */
 318                 default:        return ret;
 319                 }
 320         }
 321 #endif
 322         buf_ofs = jeb->offset;
 323
 324         if (!buf_size) {
 325                 buf_len = c->sector_size;
 326         } else {
 327                 buf_len = EMPTY_SCAN_SIZE(c->sector_size);
 328                 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
 329                 if (err)
 330                         return err;
 331         }
 332
 333         /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
 334         ofs = 0;
 335
 336         /* Scan only 4KiB of 0xFF before declaring it's empty */
 337         while(ofs < EMPTY_SCAN_SIZE(c->sector_size) && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
 338                 ofs += 4;
 339
 340         if (ofs == EMPTY_SCAN_SIZE(c->sector_size)) {
 341 #ifdef CONFIG_JFFS2_FS_NAND
 342                 if (jffs2_cleanmarker_oob(c)) {
 343                         /* scan oob, take care of cleanmarker */
 344                         int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
 345                         D2(printk(KERN_NOTICE "jffs2_check_oob_empty returned %d\n",ret));
 346                         switch (ret) {
 347                         case 0:         return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
 348                         case 1:         return BLK_STATE_ALLDIRTY;
 349                         default:        return ret;
 350                         }
 351                 }
 352 #endif
 353                 D1(printk(KERN_DEBUG "Block at 0x%08x is empty (erased)\n", jeb->offset));
 354                 return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
 355         }
 356         if (ofs) {
 357                 D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset,
 358                           jeb->offset + ofs));
 359                 DIRTY_SPACE(ofs);
 360         }
 361
 362         /* Now ofs is a complete physical flash offset as it always was... */
 363         ofs += jeb->offset;
 364
 365         noise = 10;
 366
 367 scan_more:
 368         while(ofs < jeb->offset + c->sector_size) {
 369
 370                 D1(ACCT_PARANOIA_CHECK(jeb));
 371
 372                 cond_resched();
 373
 374                 if (ofs & 3) {
 375                         printk(KERN_WARNING "Eep. ofs 0x%08x not word-aligned!\n", ofs);
 376                         ofs = PAD(ofs);
 377                         continue;
 378                 }
 379                 if (ofs == prevofs) {
 380                         printk(KERN_WARNING "ofs 0x%08x has already been seen. Skipping\n", ofs);
 381                         DIRTY_SPACE(4);
 382                         ofs += 4;
 383                         continue;
 384                 }
 385                 prevofs = ofs;
 386
 387                 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
 388                         D1(printk(KERN_DEBUG "Fewer than %zd bytes left to end of block. (%x+%x<%x+%zx) Not reading\n", sizeof(struct jffs2_unknown_node),
 389                                   jeb->offset, c->sector_size, ofs, sizeof(*node)));
 390                         DIRTY_SPACE((jeb->offset + c->sector_size)-ofs);
 391                         break;
 392                 }
 393
 394                 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
 395                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 396                         D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
 397                                   sizeof(struct jffs2_unknown_node), buf_len, ofs));
 398                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 399                         if (err)
 400                                 return err;
 401                         buf_ofs = ofs;
 402                 }
 403
 404                 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
 405
 406                 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
 407                         uint32_t inbuf_ofs;
 408                         uint32_t empty_start;
 409
 410                         empty_start = ofs;
 411                         ofs += 4;
 412
 413                         D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs));
 414                 more_empty:
 415                         inbuf_ofs = ofs - buf_ofs;
 416                         while (inbuf_ofs < buf_len) {
 417                                 if (*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff) {
 418                                         printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n",
 419                                                empty_start, ofs);
 420                                         DIRTY_SPACE(ofs-empty_start);
 421                                         goto scan_more;
 422                                 }
 423
 424                                 inbuf_ofs+=4;
 425                                 ofs += 4;
 426                         }
 427                         /* Ran off end. */
 428                         D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs));
 429
 430                         /* If we're only checking the beginning of a block with a cleanmarker,
 431                            bail now */
 432                         if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&
 433                             c->cleanmarker_size && !jeb->dirty_size && !jeb->first_node->next_in_ino) {
 434                                 D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE(c->sector_size)));
 435                                 return BLK_STATE_CLEANMARKER;
 436                         }
 437
 438                         /* See how much more there is to read in this eraseblock... */
 439                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 440                         if (!buf_len) {
 441                                 /* No more to read. Break out of main loop without marking
 442                                    this range of empty space as dirty (because it's not) */
 443                                 D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block. Treating as free_space\n",
 444                                           empty_start));
 445                                 break;
 446                         }
 447                         D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs));
 448                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 449                         if (err)
 450                                 return err;
 451                         buf_ofs = ofs;
 452                         goto more_empty;
 453                 }
 454
 455                 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
 456                         printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n", ofs);
 457                         DIRTY_SPACE(4);
 458                         ofs += 4;
 459                         continue;
 460                 }
 461                 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
 462                         D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs));
 463                         DIRTY_SPACE(4);
 464                         ofs += 4;
 465                         continue;
 466                 }
 467                 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
 468                         printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08x\n", ofs);
 469                         printk(KERN_WARNING "You cannot use older JFFS2 filesystems with newer kernels\n");
 470                         DIRTY_SPACE(4);
 471                         ofs += 4;
 472                         continue;
 473                 }
 474                 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
 475                         /* OK. We're out of possibilities. Whinge and move on */
 476                         noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n",
 477                                      JFFS2_MAGIC_BITMASK, ofs,
 478                                      je16_to_cpu(node->magic));
 479                         DIRTY_SPACE(4);
 480                         ofs += 4;
 481                         continue;
 482                 }
 483                 /* We seem to have a node of sorts. Check the CRC */
 484                 crcnode.magic = node->magic;
 485                 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
 486                 crcnode.totlen = node->totlen;
 487                 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
 488
 489                 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
 490                         noisy_printk(&noise, "jffs2_scan_eraseblock(): Node at 0x%08x {0x%04x, 0x%04x, 0x%08x) has invalid CRC 0x%08x (calculated 0x%08x)\n",
 491                                      ofs, je16_to_cpu(node->magic),
 492                                      je16_to_cpu(node->nodetype),
 493                                      je32_to_cpu(node->totlen),
 494                                      je32_to_cpu(node->hdr_crc),
 495                                      hdr_crc);
 496                         DIRTY_SPACE(4);
 497                         ofs += 4;
 498                         continue;
 499                 }
 500
 501                 if (ofs + je32_to_cpu(node->totlen) >
 502                     jeb->offset + c->sector_size) {
 503                         /* Eep. Node goes over the end of the erase block. */
 504                         printk(KERN_WARNING "Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
 505                                ofs, je32_to_cpu(node->totlen));
 506                         printk(KERN_WARNING "Perhaps the file system was created with the wrong erase size?\n");
 507                         DIRTY_SPACE(4);
 508                         ofs += 4;
 509                         continue;
 510                 }
 511
 512                 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
 513                         /* Wheee. This is an obsoleted node */
 514                         D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs));
 515                         DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 516                         ofs += PAD(je32_to_cpu(node->totlen));
 517                         continue;
 518                 }
 519
 520                 switch(je16_to_cpu(node->nodetype)) {
 521                 case JFFS2_NODETYPE_INODE:
 522                         if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
 523                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 524                                 D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
 525                                           sizeof(struct jffs2_raw_inode), buf_len, ofs));
 526                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 527                                 if (err)
 528                                         return err;
 529                                 buf_ofs = ofs;
 530                                 node = (void *)buf;
 531                         }
 532                         err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs);
 533                         if (err) return err;
 534                         ofs += PAD(je32_to_cpu(node->totlen));
 535                         break;
 536
 537                 case JFFS2_NODETYPE_DIRENT:
 538                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 539                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 540                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
 541                                           je32_to_cpu(node->totlen), buf_len, ofs));
 542                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 543                                 if (err)
 544                                         return err;
 545                                 buf_ofs = ofs;
 546                                 node = (void *)buf;
 547                         }
 548                         err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs);
 549                         if (err) return err;
 550                         ofs += PAD(je32_to_cpu(node->totlen));
 551                         break;
 552
 553                 case JFFS2_NODETYPE_CLEANMARKER:
 554                         D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs));
 555                         if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
 556                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n",
 557                                        ofs, je32_to_cpu(node->totlen), c->cleanmarker_size);
 558                                 DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
 559                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 560                         } else if (jeb->first_node) {
 561                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n", ofs, jeb->offset);
 562                                 DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
 563                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 564                         } else {
 565                                 struct jffs2_raw_node_ref *marker_ref = jffs2_alloc_raw_node_ref();
 566                                 if (!marker_ref) {
 567                                         printk(KERN_NOTICE "Failed to allocate node ref for clean marker\n");
 568                                         return -ENOMEM;
 569                                 }
 570                                 marker_ref->next_in_ino = NULL;
 571                                 marker_ref->next_phys = NULL;
 572                                 marker_ref->flash_offset = ofs | REF_NORMAL;
 573                                 marker_ref->__totlen = c->cleanmarker_size;
 574                                 jeb->first_node = jeb->last_node = marker_ref;
 575
 576                                 USED_SPACE(PAD(c->cleanmarker_size));
 577                                 ofs += PAD(c->cleanmarker_size);
 578                         }
 579                         break;
 580
 581                 case JFFS2_NODETYPE_PADDING:
 582                         DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 583                         ofs += PAD(je32_to_cpu(node->totlen));
 584                         break;
 585
 586                 default:
 587                         switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
 588                         case JFFS2_FEATURE_ROCOMPAT:
 589                                 printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 590                                 c->flags |= JFFS2_SB_FLAG_RO;
 591                                 if (!(jffs2_is_readonly(c)))
 592                                         return -EROFS;
 593                                 DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 594                                 ofs += PAD(je32_to_cpu(node->totlen));
 595                                 break;
 596
 597                         case JFFS2_FEATURE_INCOMPAT:
 598                                 printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 599                                 return -EINVAL;
 600
 601                         case JFFS2_FEATURE_RWCOMPAT_DELETE:
 602                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 603                                 DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 604                                 ofs += PAD(je32_to_cpu(node->totlen));
 605                                 break;
 606
 607                         case JFFS2_FEATURE_RWCOMPAT_COPY:
 608                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 609                                 USED_SPACE(PAD(je32_to_cpu(node->totlen)));
 610                                 ofs += PAD(je32_to_cpu(node->totlen));
 611                                 break;
 612                         }
 613                 }
 614         }
 615
 616
 617         D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x\n", jeb->offset,
 618                   jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size));
 619
 620         /* mark_node_obsolete can add to wasted !! */
 621         if (jeb->wasted_size) {
 622                 jeb->dirty_size += jeb->wasted_size;
 623                 c->dirty_size += jeb->wasted_size;
 624                 c->wasted_size -= jeb->wasted_size;
 625                 jeb->wasted_size = 0;
 626         }
 627
 628         if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size
 629                 && (!jeb->first_node || !jeb->first_node->next_in_ino) )
 630                 return BLK_STATE_CLEANMARKER;
 631
 632         /* move blocks with max 4 byte dirty space to cleanlist */
 633         else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
 634                 c->dirty_size -= jeb->dirty_size;
 635                 c->wasted_size += jeb->dirty_size;
 636                 jeb->wasted_size += jeb->dirty_size;
 637                 jeb->dirty_size = 0;
 638                 return BLK_STATE_CLEAN;
 639         } else if (jeb->used_size || jeb->unchecked_size)
 640                 return BLK_STATE_PARTDIRTY;
 641         else
 642                 return BLK_STATE_ALLDIRTY;
 643 }
 644
 645 static struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
 646 {
 647         struct jffs2_inode_cache *ic;
 648
 649         ic = jffs2_get_ino_cache(c, ino);
 650         if (ic)
 651                 return ic;
 652
 653         if (ino > c->highest_ino)
 654                 c->highest_ino = ino;
 655
 656         ic = jffs2_alloc_inode_cache();
 657         if (!ic) {
 658                 printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n");
 659                 return NULL;
 660         }
 661         memset(ic, 0, sizeof(*ic));
 662
 663         ic->ino = ino;
 664         ic->nodes = (void *)ic;
 665         jffs2_add_ino_cache(c, ic);
 666         if (ino == 1)
 667                 ic->nlink = 1;
 668         return ic;
 669 }
 670
 671 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 672                                  struct jffs2_raw_inode *ri, uint32_t ofs)
 673 {
 674         struct jffs2_raw_node_ref *raw;
 675         struct jffs2_inode_cache *ic;
 676         uint32_t ino = je32_to_cpu(ri->ino);
 677
 678         D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs));
 679
 680         /* We do very little here now. Just check the ino# to which we should attribute
 681            this node; we can do all the CRC checking etc. later. There's a tradeoff here --
 682            we used to scan the flash once only, reading everything we want from it into
 683            memory, then building all our in-core data structures and freeing the extra
 684            information. Now we allow the first part of the mount to complete a lot quicker,
 685            but we have to go _back_ to the flash in order to finish the CRC checking, etc.
 686            Which means that the _full_ amount of time to get to proper write mode with GC
 687            operational may actually be _longer_ than before. Sucks to be me. */
 688
 689         raw = jffs2_alloc_raw_node_ref();
 690         if (!raw) {
 691                 printk(KERN_NOTICE "jffs2_scan_inode_node(): allocation of node reference failed\n");
 692                 return -ENOMEM;
 693         }
 694
 695         ic = jffs2_get_ino_cache(c, ino);
 696         if (!ic) {
 697                 /* Inocache get failed. Either we read a bogus ino# or it's just genuinely the
 698                    first node we found for this inode. Do a CRC check to protect against the former
 699                    case */
 700                 uint32_t crc = crc32(0, ri, sizeof(*ri)-8);
 701
 702                 if (crc != je32_to_cpu(ri->node_crc)) {
 703                         printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 704                                ofs, je32_to_cpu(ri->node_crc), crc);
 705                         /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
 706                         DIRTY_SPACE(PAD(je32_to_cpu(ri->totlen)));
 707                         jffs2_free_raw_node_ref(raw);
 708                         return 0;
 709                 }
 710                 ic = jffs2_scan_make_ino_cache(c, ino);
 711                 if (!ic) {
 712                         jffs2_free_raw_node_ref(raw);
 713                         return -ENOMEM;
 714                 }
 715         }
 716
 717         /* Wheee. It worked */
 718
 719         raw->flash_offset = ofs | REF_UNCHECKED;
 720         raw->__totlen = PAD(je32_to_cpu(ri->totlen));
 721         raw->next_phys = NULL;
 722         raw->next_in_ino = ic->nodes;
 723
 724         ic->nodes = raw;
 725         if (!jeb->first_node)
 726                 jeb->first_node = raw;
 727         if (jeb->last_node)
 728                 jeb->last_node->next_phys = raw;
 729         jeb->last_node = raw;
 730
 731         D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
 732                   je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
 733                   je32_to_cpu(ri->offset),
 734                   je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize)));
 735
 736         pseudo_random += je32_to_cpu(ri->version);
 737
 738         UNCHECKED_SPACE(PAD(je32_to_cpu(ri->totlen)));
 739         return 0;
 740 }
 741
 742 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 743                                   struct jffs2_raw_dirent *rd, uint32_t ofs)
 744 {
 745         struct jffs2_raw_node_ref *raw;
 746         struct jffs2_full_dirent *fd;
 747         struct jffs2_inode_cache *ic;
 748         uint32_t crc;
 749
 750         D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs));
 751
 752         /* We don't get here unless the node is still valid, so we don't have to
 753            mask in the ACCURATE bit any more. */
 754         crc = crc32(0, rd, sizeof(*rd)-8);
 755
 756         if (crc != je32_to_cpu(rd->node_crc)) {
 757                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 758                        ofs, je32_to_cpu(rd->node_crc), crc);
 759                 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
 760                 DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
 761                 return 0;
 762         }
 763
 764         pseudo_random += je32_to_cpu(rd->version);
 765
 766         fd = jffs2_alloc_full_dirent(rd->nsize+1);
 767         if (!fd) {
 768                 return -ENOMEM;
 769         }
 770         memcpy(&fd->name, rd->name, rd->nsize);
 771         fd->name[rd->nsize] = 0;
 772
 773         crc = crc32(0, fd->name, rd->nsize);
 774         if (crc != je32_to_cpu(rd->name_crc)) {
 775                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 776                        ofs, je32_to_cpu(rd->name_crc), crc);
 777                 D1(printk(KERN_NOTICE "Name for which CRC failed is (now) '%s', ino #%d\n", fd->name, je32_to_cpu(rd->ino)));
 778                 jffs2_free_full_dirent(fd);
 779                 /* FIXME: Why do we believe totlen? */
 780                 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
 781                 DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
 782                 return 0;
 783         }
 784         raw = jffs2_alloc_raw_node_ref();
 785         if (!raw) {
 786                 jffs2_free_full_dirent(fd);
 787                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): allocation of node reference failed\n");
 788                 return -ENOMEM;
 789         }
 790         ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
 791         if (!ic) {
 792                 jffs2_free_full_dirent(fd);
 793                 jffs2_free_raw_node_ref(raw);
 794                 return -ENOMEM;
 795         }
 796
 797         raw->__totlen = PAD(je32_to_cpu(rd->totlen));
 798         raw->flash_offset = ofs | REF_PRISTINE;
 799         raw->next_phys = NULL;
 800         raw->next_in_ino = ic->nodes;
 801         ic->nodes = raw;
 802         if (!jeb->first_node)
 803                 jeb->first_node = raw;
 804         if (jeb->last_node)
 805                 jeb->last_node->next_phys = raw;
 806         jeb->last_node = raw;
 807
 808         fd->raw = raw;
 809         fd->next = NULL;
 810         fd->version = je32_to_cpu(rd->version);
 811         fd->ino = je32_to_cpu(rd->ino);
 812         fd->nhash = full_name_hash(fd->name, rd->nsize);
 813         fd->type = rd->type;
 814         USED_SPACE(PAD(je32_to_cpu(rd->totlen)));
 815         jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
 816
 817         return 0;
 818 }
 819
 820 static int count_list(struct list_head *l)
 821 {
 822         uint32_t count = 0;
 823         struct list_head *tmp;
 824
 825         list_for_each(tmp, l) {
 826                 count++;
 827         }
 828         return count;
 829 }
 830
 831 /* Note: This breaks if list_empty(head). I don't care. You
 832    might, if you copy this code and use it elsewhere :) */
 833 static void rotate_list(struct list_head *head, uint32_t count)
 834 {
 835         struct list_head *n = head->next;
 836
 837         list_del(head);
 838         while(count--) {
 839                 n = n->next;
 840         }
 841         list_add(head, n);
 842 }
 843
 844 void jffs2_rotate_lists(struct jffs2_sb_info *c)
 845 {
 846         uint32_t x;
 847         uint32_t rotateby;
 848
 849         x = count_list(&c->clean_list);
 850         if (x) {
 851                 rotateby = pseudo_random % x;
 852                 D1(printk(KERN_DEBUG "Rotating clean_list by %d\n", rotateby));
 853
 854                 rotate_list((&c->clean_list), rotateby);
 855
 856                 D1(printk(KERN_DEBUG "Erase block at front of clean_list is at %08x\n",
 857                           list_entry(c->clean_list.next, struct jffs2_eraseblock, list)->offset));
 858         } else {
 859                 D1(printk(KERN_DEBUG "Not rotating empty clean_list\n"));
 860         }
 861
 862         x = count_list(&c->very_dirty_list);
 863         if (x) {
 864                 rotateby = pseudo_random % x;
 865                 D1(printk(KERN_DEBUG "Rotating very_dirty_list by %d\n", rotateby));
 866
 867                 rotate_list((&c->very_dirty_list), rotateby);
 868
 869                 D1(printk(KERN_DEBUG "Erase block at front of very_dirty_list is at %08x\n",
 870                           list_entry(c->very_dirty_list.next, struct jffs2_eraseblock, list)->offset));
 871         } else {
 872                 D1(printk(KERN_DEBUG "Not rotating empty very_dirty_list\n"));
 873         }
 874
 875         x = count_list(&c->dirty_list);
 876         if (x) {
 877                 rotateby = pseudo_random % x;
 878                 D1(printk(KERN_DEBUG "Rotating dirty_list by %d\n", rotateby));
 879
 880                 rotate_list((&c->dirty_list), rotateby);
 881
 882                 D1(printk(KERN_DEBUG "Erase block at front of dirty_list is at %08x\n",
 883                           list_entry(c->dirty_list.next, struct jffs2_eraseblock, list)->offset));
 884         } else {
 885                 D1(printk(KERN_DEBUG "Not rotating empty dirty_list\n"));
 886         }
 887
 888         x = count_list(&c->erasable_list);
 889         if (x) {
 890                 rotateby = pseudo_random % x;
 891                 D1(printk(KERN_DEBUG "Rotating erasable_list by %d\n", rotateby));
 892
 893                 rotate_list((&c->erasable_list), rotateby);
 894
 895                 D1(printk(KERN_DEBUG "Erase block at front of erasable_list is at %08x\n",
 896                           list_entry(c->erasable_list.next, struct jffs2_eraseblock, list)->offset));
 897         } else {
 898                 D1(printk(KERN_DEBUG "Not rotating empty erasable_list\n"));
 899         }
 900
 901         if (c->nr_erasing_blocks) {
 902                 rotateby = pseudo_random % c->nr_erasing_blocks;
 903                 D1(printk(KERN_DEBUG "Rotating erase_pending_list by %d\n", rotateby));
 904
 905                 rotate_list((&c->erase_pending_list), rotateby);
 906
 907                 D1(printk(KERN_DEBUG "Erase block at front of erase_pending_list is at %08x\n",
 908                           list_entry(c->erase_pending_list.next, struct jffs2_eraseblock, list)->offset));
 909         } else {
 910                 D1(printk(KERN_DEBUG "Not rotating empty erase_pending_list\n"));
 911         }
 912
 913         if (c->nr_free_blocks) {
 914                 rotateby = pseudo_random % c->nr_free_blocks;
 915                 D1(printk(KERN_DEBUG "Rotating free_list by %d\n", rotateby));
 916
 917                 rotate_list((&c->free_list), rotateby);
 918
 919                 D1(printk(KERN_DEBUG "Erase block at front of free_list is at %08x\n",
 920                           list_entry(c->free_list.next, struct jffs2_eraseblock, list)->offset));
 921         } else {
 922                 D1(printk(KERN_DEBUG "Not rotating empty free_list\n"));
 923         }
 924 }