fs/jffs2/scan.c

   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 1.115 2004/11/17 12:59:08 dedekind 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 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 int jffs2_scan_medium(struct jffs2_sb_info *c)
  79 {
  80         int i, ret;
  81         uint32_t empty_blocks = 0, bad_blocks = 0;
  82         unsigned char *flashbuf = NULL;
  83         uint32_t buf_size = 0;
  84 #ifndef __ECOS
  85         size_t pointlen;
  86
  87         if (c->mtd->point) {
  88                 ret = c->mtd->point (c->mtd, 0, c->mtd->size, &pointlen, &flashbuf);
  89                 if (!ret && pointlen < c->mtd->size) {
  90                         /* Don't muck about if it won't let us point to the whole flash */
  91                         D1(printk(KERN_DEBUG "MTD point returned len too short: 0x%zx\n", pointlen));
  92                         c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
  93                         flashbuf = NULL;
  94                 }
  95                 if (ret)
  96                         D1(printk(KERN_DEBUG "MTD point failed %d\n", ret));
  97         }
  98 #endif
  99         if (!flashbuf) {
 100                 /* For NAND it's quicker to read a whole eraseblock at a time,
 101                    apparently */
 102                 if (jffs2_cleanmarker_oob(c))
 103                         buf_size = c->sector_size;
 104                 else
 105                         buf_size = PAGE_SIZE;
 106
 107                 /* Respect kmalloc limitations */
 108                 if (buf_size > 128*1024)
 109                         buf_size = 128*1024;
 110
 111                 D1(printk(KERN_DEBUG "Allocating readbuf of %d bytes\n", buf_size));
 112                 flashbuf = kmalloc(buf_size, GFP_KERNEL);
 113                 if (!flashbuf)
 114                         return -ENOMEM;
 115         }
 116
 117         for (i=0; i<c->nr_blocks; i++) {
 118                 struct jffs2_eraseblock *jeb = &c->blocks[i];
 119
 120                 ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset), buf_size);
 121
 122                 if (ret < 0)
 123                         goto out;
 124
 125                 ACCT_PARANOIA_CHECK(jeb);
 126
 127                 /* Now decide which list to put it on */
 128                 switch(ret) {
 129                 case BLK_STATE_ALLFF:
 130                         /*
 131                          * Empty block.   Since we can't be sure it
 132                          * was entirely erased, we just queue it for erase
 133                          * again.  It will be marked as such when the erase
 134                          * is complete.  Meanwhile we still count it as empty
 135                          * for later checks.
 136                          */
 137                         empty_blocks++;
 138                         list_add(&jeb->list, &c->erase_pending_list);
 139                         c->nr_erasing_blocks++;
 140                         break;
 141
 142                 case BLK_STATE_CLEANMARKER:
 143                         /* Only a CLEANMARKER node is valid */
 144                         if (!jeb->dirty_size) {
 145                                 /* It's actually free */
 146                                 list_add(&jeb->list, &c->free_list);
 147                                 c->nr_free_blocks++;
 148                         } else {
 149                                 /* Dirt */
 150                                 D1(printk(KERN_DEBUG "Adding all-dirty block at 0x%08x to erase_pending_list\n", jeb->offset));
 151                                 list_add(&jeb->list, &c->erase_pending_list);
 152                                 c->nr_erasing_blocks++;
 153                         }
 154                         break;
 155
 156                 case BLK_STATE_CLEAN:
 157                         /* Full (or almost full) of clean data. Clean list */
 158                         list_add(&jeb->list, &c->clean_list);
 159                         break;
 160
 161                 case BLK_STATE_PARTDIRTY:
 162                         /* Some data, but not full. Dirty list. */
 163                         /* We want to remember the block with most free space
 164                            and stick it in the 'nextblock' position to start writing to it. */
 165                         if (jeb->free_size > min_free(c) &&
 166                             (!c->nextblock || c->nextblock->free_size < jeb->free_size)) {
 167                                 /* Better candidate for the next writes to go to */
 168                                 if (c->nextblock) {
 169                                         c->nextblock->dirty_size += c->nextblock->free_size + c->nextblock->wasted_size;
 170                                         c->dirty_size += c->nextblock->free_size + c->nextblock->wasted_size;
 171                                         c->free_size -= c->nextblock->free_size;
 172                                         c->wasted_size -= c->nextblock->wasted_size;
 173                                         c->nextblock->free_size = c->nextblock->wasted_size = 0;
 174                                         if (VERYDIRTY(c, c->nextblock->dirty_size)) {
 175                                                 list_add(&c->nextblock->list, &c->very_dirty_list);
 176                                         } else {
 177                                                 list_add(&c->nextblock->list, &c->dirty_list);
 178                                         }
 179                                 }
 180                                 c->nextblock = jeb;
 181                         } else {
 182                                 jeb->dirty_size += jeb->free_size + jeb->wasted_size;
 183                                 c->dirty_size += jeb->free_size + jeb->wasted_size;
 184                                 c->free_size -= jeb->free_size;
 185                                 c->wasted_size -= jeb->wasted_size;
 186                                 jeb->free_size = jeb->wasted_size = 0;
 187                                 if (VERYDIRTY(c, jeb->dirty_size)) {
 188                                         list_add(&jeb->list, &c->very_dirty_list);
 189                                 } else {
 190                                         list_add(&jeb->list, &c->dirty_list);
 191                                 }
 192                         }
 193                         break;
 194
 195                 case BLK_STATE_ALLDIRTY:
 196                         /* Nothing valid - not even a clean marker. Needs erasing. */
 197                         /* For now we just put it on the erasing list. We'll start the erases later */
 198                         D1(printk(KERN_NOTICE "JFFS2: Erase block at 0x%08x is not formatted. It will be erased\n", jeb->offset));
 199                         list_add(&jeb->list, &c->erase_pending_list);
 200                         c->nr_erasing_blocks++;
 201                         break;
 202
 203                 case BLK_STATE_BADBLOCK:
 204                         D1(printk(KERN_NOTICE "JFFS2: Block at 0x%08x is bad\n", jeb->offset));
 205                         list_add(&jeb->list, &c->bad_list);
 206                         c->bad_size += c->sector_size;
 207                         c->free_size -= c->sector_size;
 208                         bad_blocks++;
 209                         break;
 210                 default:
 211                         printk(KERN_WARNING "jffs2_scan_medium(): unknown block state\n");
 212                         BUG();
 213                 }
 214         }
 215
 216         /* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
 217         if (c->nextblock && (c->nextblock->dirty_size)) {
 218                 c->nextblock->wasted_size += c->nextblock->dirty_size;
 219                 c->wasted_size += c->nextblock->dirty_size;
 220                 c->dirty_size -= c->nextblock->dirty_size;
 221                 c->nextblock->dirty_size = 0;
 222         }
 223 #if defined CONFIG_JFFS2_FS_NAND || defined CONFIG_JFFS2_FS_NOR_ECC
 224         if (!jffs2_can_mark_obsolete(c) && c->nextblock && (c->nextblock->free_size & (c->wbuf_pagesize-1))) {
 225                 /* If we're going to start writing into a block which already
 226                    contains data, and the end of the data isn't page-aligned,
 227                    skip a little and align it. */
 228
 229                 uint32_t skip = c->nextblock->free_size & (c->wbuf_pagesize-1);
 230
 231                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): Skipping %d bytes in nextblock to ensure page alignment\n",
 232                           skip));
 233                 c->nextblock->wasted_size += skip;
 234                 c->wasted_size += skip;
 235
 236                 c->nextblock->free_size -= skip;
 237                 c->free_size -= skip;
 238         }
 239 #endif
 240         if (c->nr_erasing_blocks) {
 241                 if ( !c->used_size && ((c->nr_free_blocks+empty_blocks+bad_blocks)!= c->nr_blocks || bad_blocks == c->nr_blocks) ) {
 242                         printk(KERN_NOTICE "Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
 243                         printk(KERN_NOTICE "empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",empty_blocks,bad_blocks,c->nr_blocks);
 244                         ret = -EIO;
 245                         goto out;
 246                 }
 247                 jffs2_erase_pending_trigger(c);
 248         }
 249         ret = 0;
 250  out:
 251         if (buf_size)
 252                 kfree(flashbuf);
 253 #ifndef __ECOS
 254         else
 255                 c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
 256 #endif
 257         return ret;
 258 }
 259
 260 static int jffs2_fill_scan_buf (struct jffs2_sb_info *c, unsigned char *buf,
 261                                 uint32_t ofs, uint32_t len)
 262 {
 263         int ret;
 264         size_t retlen;
 265
 266         ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
 267         if (ret) {
 268                 D1(printk(KERN_WARNING "mtd->read(0x%x bytes from 0x%x) returned %d\n", len, ofs, ret));
 269                 return ret;
 270         }
 271         if (retlen < len) {
 272                 D1(printk(KERN_WARNING "Read at 0x%x gave only 0x%zx bytes\n", ofs, retlen));
 273                 return -EIO;
 274         }
 275         D2(printk(KERN_DEBUG "Read 0x%x bytes from 0x%08x into buf\n", len, ofs));
 276         D2(printk(KERN_DEBUG "000: %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x\n",
 277                   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]));
 278         return 0;
 279 }
 280
 281 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 282                                   unsigned char *buf, uint32_t buf_size) {
 283         struct jffs2_unknown_node *node;
 284         struct jffs2_unknown_node crcnode;
 285         uint32_t ofs, prevofs;
 286         uint32_t hdr_crc, buf_ofs, buf_len;
 287         int err;
 288         int noise = 0;
 289 #ifdef CONFIG_JFFS2_FS_NAND
 290         int cleanmarkerfound = 0;
 291 #endif
 292
 293         ofs = jeb->offset;
 294         prevofs = jeb->offset - 1;
 295
 296         D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs));
 297
 298 #ifdef CONFIG_JFFS2_FS_NAND
 299         if (jffs2_cleanmarker_oob(c)) {
 300                 int ret = jffs2_check_nand_cleanmarker(c, jeb);
 301                 D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n",ret));
 302                 /* Even if it's not found, we still scan to see
 303                    if the block is empty. We use this information
 304                    to decide whether to erase it or not. */
 305                 switch (ret) {
 306                 case 0:         cleanmarkerfound = 1; break;
 307                 case 1:         break;
 308                 case 2:         return BLK_STATE_BADBLOCK;
 309                 case 3:         return BLK_STATE_ALLDIRTY; /* Block has failed to erase min. once */
 310                 default:        return ret;
 311                 }
 312         }
 313 #endif
 314         buf_ofs = jeb->offset;
 315
 316         if (!buf_size) {
 317                 buf_len = c->sector_size;
 318         } else {
 319                 buf_len = EMPTY_SCAN_SIZE;
 320                 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
 321                 if (err)
 322                         return err;
 323         }
 324
 325         /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
 326         ofs = 0;
 327
 328         /* Scan only 4KiB of 0xFF before declaring it's empty */
 329         while(ofs < EMPTY_SCAN_SIZE && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
 330                 ofs += 4;
 331
 332         if (ofs == EMPTY_SCAN_SIZE) {
 333 #ifdef CONFIG_JFFS2_FS_NAND
 334                 if (jffs2_cleanmarker_oob(c)) {
 335                         /* scan oob, take care of cleanmarker */
 336                         int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
 337                         D2(printk(KERN_NOTICE "jffs2_check_oob_empty returned %d\n",ret));
 338                         switch (ret) {
 339                         case 0:         return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
 340                         case 1:         return BLK_STATE_ALLDIRTY;
 341                         default:        return ret;
 342                         }
 343                 }
 344 #endif
 345                 D1(printk(KERN_DEBUG "Block at 0x%08x is empty (erased)\n", jeb->offset));
 346                 return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
 347         }
 348         if (ofs) {
 349                 D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset,
 350                           jeb->offset + ofs));
 351                 DIRTY_SPACE(ofs);
 352         }
 353
 354         /* Now ofs is a complete physical flash offset as it always was... */
 355         ofs += jeb->offset;
 356
 357         noise = 10;
 358
 359 scan_more:
 360         while(ofs < jeb->offset + c->sector_size) {
 361
 362                 D1(ACCT_PARANOIA_CHECK(jeb));
 363
 364                 cond_resched();
 365
 366                 if (ofs & 3) {
 367                         printk(KERN_WARNING "Eep. ofs 0x%08x not word-aligned!\n", ofs);
 368                         ofs = PAD(ofs);
 369                         continue;
 370                 }
 371                 if (ofs == prevofs) {
 372                         printk(KERN_WARNING "ofs 0x%08x has already been seen. Skipping\n", ofs);
 373                         DIRTY_SPACE(4);
 374                         ofs += 4;
 375                         continue;
 376                 }
 377                 prevofs = ofs;
 378
 379                 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
 380                         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),
 381                                   jeb->offset, c->sector_size, ofs, sizeof(*node)));
 382                         DIRTY_SPACE((jeb->offset + c->sector_size)-ofs);
 383                         break;
 384                 }
 385
 386                 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
 387                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 388                         D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
 389                                   sizeof(struct jffs2_unknown_node), buf_len, ofs));
 390                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 391                         if (err)
 392                                 return err;
 393                         buf_ofs = ofs;
 394                 }
 395
 396                 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
 397
 398                 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
 399                         uint32_t inbuf_ofs;
 400                         uint32_t empty_start;
 401
 402                         empty_start = ofs;
 403                         ofs += 4;
 404
 405                         D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs));
 406                 more_empty:
 407                         inbuf_ofs = ofs - buf_ofs;
 408                         while (inbuf_ofs < buf_len) {
 409                                 if (*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff) {
 410                                         printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n",
 411                                                empty_start, ofs);
 412                                         DIRTY_SPACE(ofs-empty_start);
 413                                         goto scan_more;
 414                                 }
 415
 416                                 inbuf_ofs+=4;
 417                                 ofs += 4;
 418                         }
 419                         /* Ran off end. */
 420                         D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs));
 421
 422                         /* If we're only checking the beginning of a block with a cleanmarker,
 423                            bail now */
 424                         if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&
 425                             c->cleanmarker_size && !jeb->dirty_size && !jeb->first_node->next_in_ino) {
 426                                 D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE));
 427                                 return BLK_STATE_CLEANMARKER;
 428                         }
 429
 430                         /* See how much more there is to read in this eraseblock... */
 431                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 432                         if (!buf_len) {
 433                                 /* No more to read. Break out of main loop without marking
 434                                    this range of empty space as dirty (because it's not) */
 435                                 D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block. Treating as free_space\n",
 436                                           empty_start));
 437                                 break;
 438                         }
 439                         D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs));
 440                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 441                         if (err)
 442                                 return err;
 443                         buf_ofs = ofs;
 444                         goto more_empty;
 445                 }
 446
 447                 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
 448                         printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n", ofs);
 449                         DIRTY_SPACE(4);
 450                         ofs += 4;
 451                         continue;
 452                 }
 453                 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
 454                         D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs));
 455                         DIRTY_SPACE(4);
 456                         ofs += 4;
 457                         continue;
 458                 }
 459                 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
 460                         printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08x\n", ofs);
 461                         printk(KERN_WARNING "You cannot use older JFFS2 filesystems with newer kernels\n");
 462                         DIRTY_SPACE(4);
 463                         ofs += 4;
 464                         continue;
 465                 }
 466                 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
 467                         /* OK. We're out of possibilities. Whinge and move on */
 468                         noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n",
 469                                      JFFS2_MAGIC_BITMASK, ofs,
 470                                      je16_to_cpu(node->magic));
 471                         DIRTY_SPACE(4);
 472                         ofs += 4;
 473                         continue;
 474                 }
 475                 /* We seem to have a node of sorts. Check the CRC */
 476                 crcnode.magic = node->magic;
 477                 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
 478                 crcnode.totlen = node->totlen;
 479                 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
 480
 481                 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
 482                         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",
 483                                      ofs, je16_to_cpu(node->magic),
 484                                      je16_to_cpu(node->nodetype),
 485                                      je32_to_cpu(node->totlen),
 486                                      je32_to_cpu(node->hdr_crc),
 487                                      hdr_crc);
 488                         DIRTY_SPACE(4);
 489                         ofs += 4;
 490                         continue;
 491                 }
 492
 493                 if (ofs + je32_to_cpu(node->totlen) >
 494                     jeb->offset + c->sector_size) {
 495                         /* Eep. Node goes over the end of the erase block. */
 496                         printk(KERN_WARNING "Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
 497                                ofs, je32_to_cpu(node->totlen));
 498                         printk(KERN_WARNING "Perhaps the file system was created with the wrong erase size?\n");
 499                         DIRTY_SPACE(4);
 500                         ofs += 4;
 501                         continue;
 502                 }
 503
 504                 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
 505                         /* Wheee. This is an obsoleted node */
 506                         D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs));
 507                         DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 508                         ofs += PAD(je32_to_cpu(node->totlen));
 509                         continue;
 510                 }
 511
 512                 switch(je16_to_cpu(node->nodetype)) {
 513                 case JFFS2_NODETYPE_INODE:
 514                         if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
 515                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 516                                 D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
 517                                           sizeof(struct jffs2_raw_inode), buf_len, ofs));
 518                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 519                                 if (err)
 520                                         return err;
 521                                 buf_ofs = ofs;
 522                                 node = (void *)buf;
 523                         }
 524                         err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs);
 525                         if (err) return err;
 526                         ofs += PAD(je32_to_cpu(node->totlen));
 527                         break;
 528
 529                 case JFFS2_NODETYPE_DIRENT:
 530                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 531                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 532                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
 533                                           je32_to_cpu(node->totlen), buf_len, ofs));
 534                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 535                                 if (err)
 536                                         return err;
 537                                 buf_ofs = ofs;
 538                                 node = (void *)buf;
 539                         }
 540                         err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs);
 541                         if (err) return err;
 542                         ofs += PAD(je32_to_cpu(node->totlen));
 543                         break;
 544
 545                 case JFFS2_NODETYPE_CLEANMARKER:
 546                         D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs));
 547                         if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
 548                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n",
 549                                        ofs, je32_to_cpu(node->totlen), c->cleanmarker_size);
 550                                 DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
 551                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 552                         } else if (jeb->first_node) {
 553                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n", ofs, jeb->offset);
 554                                 DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
 555                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 556                         } else {
 557                                 struct jffs2_raw_node_ref *marker_ref = jffs2_alloc_raw_node_ref();
 558                                 if (!marker_ref) {
 559                                         printk(KERN_NOTICE "Failed to allocate node ref for clean marker\n");
 560                                         return -ENOMEM;
 561                                 }
 562                                 marker_ref->next_in_ino = NULL;
 563                                 marker_ref->next_phys = NULL;
 564                                 marker_ref->flash_offset = ofs | REF_NORMAL;
 565                                 marker_ref->__totlen = c->cleanmarker_size;
 566                                 jeb->first_node = jeb->last_node = marker_ref;
 567
 568                                 USED_SPACE(PAD(c->cleanmarker_size));
 569                                 ofs += PAD(c->cleanmarker_size);
 570                         }
 571                         break;
 572
 573                 case JFFS2_NODETYPE_PADDING:
 574                         DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 575                         ofs += PAD(je32_to_cpu(node->totlen));
 576                         break;
 577
 578                 default:
 579                         switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
 580                         case JFFS2_FEATURE_ROCOMPAT:
 581                                 printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 582                                 c->flags |= JFFS2_SB_FLAG_RO;
 583                                 if (!(jffs2_is_readonly(c)))
 584                                         return -EROFS;
 585                                 DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 586                                 ofs += PAD(je32_to_cpu(node->totlen));
 587                                 break;
 588
 589                         case JFFS2_FEATURE_INCOMPAT:
 590                                 printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 591                                 return -EINVAL;
 592
 593                         case JFFS2_FEATURE_RWCOMPAT_DELETE:
 594                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 595                                 DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 596                                 ofs += PAD(je32_to_cpu(node->totlen));
 597                                 break;
 598
 599                         case JFFS2_FEATURE_RWCOMPAT_COPY:
 600                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 601                                 USED_SPACE(PAD(je32_to_cpu(node->totlen)));
 602                                 ofs += PAD(je32_to_cpu(node->totlen));
 603                                 break;
 604                         }
 605                 }
 606         }
 607
 608
 609         D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x\n", jeb->offset,
 610                   jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size));
 611
 612         /* mark_node_obsolete can add to wasted !! */
 613         if (jeb->wasted_size) {
 614                 jeb->dirty_size += jeb->wasted_size;
 615                 c->dirty_size += jeb->wasted_size;
 616                 c->wasted_size -= jeb->wasted_size;
 617                 jeb->wasted_size = 0;
 618         }
 619
 620         if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size
 621                 && (!jeb->first_node || !jeb->first_node->next_in_ino) )
 622                 return BLK_STATE_CLEANMARKER;
 623
 624         /* move blocks with max 4 byte dirty space to cleanlist */
 625         else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
 626                 c->dirty_size -= jeb->dirty_size;
 627                 c->wasted_size += jeb->dirty_size;
 628                 jeb->wasted_size += jeb->dirty_size;
 629                 jeb->dirty_size = 0;
 630                 return BLK_STATE_CLEAN;
 631         } else if (jeb->used_size || jeb->unchecked_size)
 632                 return BLK_STATE_PARTDIRTY;
 633         else
 634                 return BLK_STATE_ALLDIRTY;
 635 }
 636
 637 static struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
 638 {
 639         struct jffs2_inode_cache *ic;
 640
 641         ic = jffs2_get_ino_cache(c, ino);
 642         if (ic)
 643                 return ic;
 644
 645         if (ino > c->highest_ino)
 646                 c->highest_ino = ino;
 647
 648         ic = jffs2_alloc_inode_cache();
 649         if (!ic) {
 650                 printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n");
 651                 return NULL;
 652         }
 653         memset(ic, 0, sizeof(*ic));
 654
 655         ic->ino = ino;
 656         ic->nodes = (void *)ic;
 657         jffs2_add_ino_cache(c, ic);
 658         if (ino == 1)
 659                 ic->nlink = 1;
 660         return ic;
 661 }
 662
 663 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 664                                  struct jffs2_raw_inode *ri, uint32_t ofs)
 665 {
 666         struct jffs2_raw_node_ref *raw;
 667         struct jffs2_inode_cache *ic;
 668         uint32_t ino = je32_to_cpu(ri->ino);
 669
 670         D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs));
 671
 672         /* We do very little here now. Just check the ino# to which we should attribute
 673            this node; we can do all the CRC checking etc. later. There's a tradeoff here --
 674            we used to scan the flash once only, reading everything we want from it into
 675            memory, then building all our in-core data structures and freeing the extra
 676            information. Now we allow the first part of the mount to complete a lot quicker,
 677            but we have to go _back_ to the flash in order to finish the CRC checking, etc.
 678            Which means that the _full_ amount of time to get to proper write mode with GC
 679            operational may actually be _longer_ than before. Sucks to be me. */
 680
 681         raw = jffs2_alloc_raw_node_ref();
 682         if (!raw) {
 683                 printk(KERN_NOTICE "jffs2_scan_inode_node(): allocation of node reference failed\n");
 684                 return -ENOMEM;
 685         }
 686
 687         ic = jffs2_get_ino_cache(c, ino);
 688         if (!ic) {
 689                 /* Inocache get failed. Either we read a bogus ino# or it's just genuinely the
 690                    first node we found for this inode. Do a CRC check to protect against the former
 691                    case */
 692                 uint32_t crc = crc32(0, ri, sizeof(*ri)-8);
 693
 694                 if (crc != je32_to_cpu(ri->node_crc)) {
 695                         printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 696                                ofs, je32_to_cpu(ri->node_crc), crc);
 697                         /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
 698                         DIRTY_SPACE(PAD(je32_to_cpu(ri->totlen)));
 699                         jffs2_free_raw_node_ref(raw);
 700                         return 0;
 701                 }
 702                 ic = jffs2_scan_make_ino_cache(c, ino);
 703                 if (!ic) {
 704                         jffs2_free_raw_node_ref(raw);
 705                         return -ENOMEM;
 706                 }
 707         }
 708
 709         /* Wheee. It worked */
 710
 711         raw->flash_offset = ofs | REF_UNCHECKED;
 712         raw->__totlen = PAD(je32_to_cpu(ri->totlen));
 713         raw->next_phys = NULL;
 714         raw->next_in_ino = ic->nodes;
 715
 716         ic->nodes = raw;
 717         if (!jeb->first_node)
 718                 jeb->first_node = raw;
 719         if (jeb->last_node)
 720                 jeb->last_node->next_phys = raw;
 721         jeb->last_node = raw;
 722
 723         D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
 724                   je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
 725                   je32_to_cpu(ri->offset),
 726                   je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize)));
 727
 728         pseudo_random += je32_to_cpu(ri->version);
 729
 730         UNCHECKED_SPACE(PAD(je32_to_cpu(ri->totlen)));
 731         return 0;
 732 }
 733
 734 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 735                                   struct jffs2_raw_dirent *rd, uint32_t ofs)
 736 {
 737         struct jffs2_raw_node_ref *raw;
 738         struct jffs2_full_dirent *fd;
 739         struct jffs2_inode_cache *ic;
 740         uint32_t crc;
 741
 742         D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs));
 743
 744         /* We don't get here unless the node is still valid, so we don't have to
 745            mask in the ACCURATE bit any more. */
 746         crc = crc32(0, rd, sizeof(*rd)-8);
 747
 748         if (crc != je32_to_cpu(rd->node_crc)) {
 749                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 750                        ofs, je32_to_cpu(rd->node_crc), crc);
 751                 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
 752                 DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
 753                 return 0;
 754         }
 755
 756         pseudo_random += je32_to_cpu(rd->version);
 757
 758         fd = jffs2_alloc_full_dirent(rd->nsize+1);
 759         if (!fd) {
 760                 return -ENOMEM;
 761         }
 762         memcpy(&fd->name, rd->name, rd->nsize);
 763         fd->name[rd->nsize] = 0;
 764
 765         crc = crc32(0, fd->name, rd->nsize);
 766         if (crc != je32_to_cpu(rd->name_crc)) {
 767                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 768                        ofs, je32_to_cpu(rd->name_crc), crc);
 769                 D1(printk(KERN_NOTICE "Name for which CRC failed is (now) '%s', ino #%d\n", fd->name, je32_to_cpu(rd->ino)));
 770                 jffs2_free_full_dirent(fd);
 771                 /* FIXME: Why do we believe totlen? */
 772                 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
 773                 DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
 774                 return 0;
 775         }
 776         raw = jffs2_alloc_raw_node_ref();
 777         if (!raw) {
 778                 jffs2_free_full_dirent(fd);
 779                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): allocation of node reference failed\n");
 780                 return -ENOMEM;
 781         }
 782         ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
 783         if (!ic) {
 784                 jffs2_free_full_dirent(fd);
 785                 jffs2_free_raw_node_ref(raw);
 786                 return -ENOMEM;
 787         }
 788
 789         raw->__totlen = PAD(je32_to_cpu(rd->totlen));
 790         raw->flash_offset = ofs | REF_PRISTINE;
 791         raw->next_phys = NULL;
 792         raw->next_in_ino = ic->nodes;
 793         ic->nodes = raw;
 794         if (!jeb->first_node)
 795                 jeb->first_node = raw;
 796         if (jeb->last_node)
 797                 jeb->last_node->next_phys = raw;
 798         jeb->last_node = raw;
 799
 800         fd->raw = raw;
 801         fd->next = NULL;
 802         fd->version = je32_to_cpu(rd->version);
 803         fd->ino = je32_to_cpu(rd->ino);
 804         fd->nhash = full_name_hash(fd->name, rd->nsize);
 805         fd->type = rd->type;
 806         USED_SPACE(PAD(je32_to_cpu(rd->totlen)));
 807         jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
 808
 809         return 0;
 810 }
 811
 812 static int count_list(struct list_head *l)
 813 {
 814         uint32_t count = 0;
 815         struct list_head *tmp;
 816
 817         list_for_each(tmp, l) {
 818                 count++;
 819         }
 820         return count;
 821 }
 822
 823 /* Note: This breaks if list_empty(head). I don't care. You
 824    might, if you copy this code and use it elsewhere :) */
 825 static void rotate_list(struct list_head *head, uint32_t count)
 826 {
 827         struct list_head *n = head->next;
 828
 829         list_del(head);
 830         while(count--) {
 831                 n = n->next;
 832         }
 833         list_add(head, n);
 834 }
 835
 836 void jffs2_rotate_lists(struct jffs2_sb_info *c)
 837 {
 838         uint32_t x;
 839         uint32_t rotateby;
 840
 841         x = count_list(&c->clean_list);
 842         if (x) {
 843                 rotateby = pseudo_random % x;
 844                 D1(printk(KERN_DEBUG "Rotating clean_list by %d\n", rotateby));
 845
 846                 rotate_list((&c->clean_list), rotateby);
 847
 848                 D1(printk(KERN_DEBUG "Erase block at front of clean_list is at %08x\n",
 849                           list_entry(c->clean_list.next, struct jffs2_eraseblock, list)->offset));
 850         } else {
 851                 D1(printk(KERN_DEBUG "Not rotating empty clean_list\n"));
 852         }
 853
 854         x = count_list(&c->very_dirty_list);
 855         if (x) {
 856                 rotateby = pseudo_random % x;
 857                 D1(printk(KERN_DEBUG "Rotating very_dirty_list by %d\n", rotateby));
 858
 859                 rotate_list((&c->very_dirty_list), rotateby);
 860
 861                 D1(printk(KERN_DEBUG "Erase block at front of very_dirty_list is at %08x\n",
 862                           list_entry(c->very_dirty_list.next, struct jffs2_eraseblock, list)->offset));
 863         } else {
 864                 D1(printk(KERN_DEBUG "Not rotating empty very_dirty_list\n"));
 865         }
 866
 867         x = count_list(&c->dirty_list);
 868         if (x) {
 869                 rotateby = pseudo_random % x;
 870                 D1(printk(KERN_DEBUG "Rotating dirty_list by %d\n", rotateby));
 871
 872                 rotate_list((&c->dirty_list), rotateby);
 873
 874                 D1(printk(KERN_DEBUG "Erase block at front of dirty_list is at %08x\n",
 875                           list_entry(c->dirty_list.next, struct jffs2_eraseblock, list)->offset));
 876         } else {
 877                 D1(printk(KERN_DEBUG "Not rotating empty dirty_list\n"));
 878         }
 879
 880         x = count_list(&c->erasable_list);
 881         if (x) {
 882                 rotateby = pseudo_random % x;
 883                 D1(printk(KERN_DEBUG "Rotating erasable_list by %d\n", rotateby));
 884
 885                 rotate_list((&c->erasable_list), rotateby);
 886
 887                 D1(printk(KERN_DEBUG "Erase block at front of erasable_list is at %08x\n",
 888                           list_entry(c->erasable_list.next, struct jffs2_eraseblock, list)->offset));
 889         } else {
 890                 D1(printk(KERN_DEBUG "Not rotating empty erasable_list\n"));
 891         }
 892
 893         if (c->nr_erasing_blocks) {
 894                 rotateby = pseudo_random % c->nr_erasing_blocks;
 895                 D1(printk(KERN_DEBUG "Rotating erase_pending_list by %d\n", rotateby));
 896
 897                 rotate_list((&c->erase_pending_list), rotateby);
 898
 899                 D1(printk(KERN_DEBUG "Erase block at front of erase_pending_list is at %08x\n",
 900                           list_entry(c->erase_pending_list.next, struct jffs2_eraseblock, list)->offset));
 901         } else {
 902                 D1(printk(KERN_DEBUG "Not rotating empty erase_pending_list\n"));
 903         }
 904
 905         if (c->nr_free_blocks) {
 906                 rotateby = pseudo_random % c->nr_free_blocks;
 907                 D1(printk(KERN_DEBUG "Rotating free_list by %d\n", rotateby));
 908
 909                 rotate_list((&c->free_list), rotateby);
 910
 911                 D1(printk(KERN_DEBUG "Erase block at front of free_list is at %08x\n",
 912                           list_entry(c->free_list.next, struct jffs2_eraseblock, list)->offset));
 913         } else {
 914                 D1(printk(KERN_DEBUG "Not rotating empty free_list\n"));
 915         }
 916 }