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 1.125 2005/09/30 13:59:13 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 #include "summary.h"
  22 #include "debug.h"
  23
  24 #define DEFAULT_EMPTY_SCAN_SIZE 1024
  25
  26 #define noisy_printk(noise, args...) do { \
  27         if (*(noise)) { \
  28                 printk(KERN_NOTICE args); \
  29                  (*(noise))--; \
  30                  if (!(*(noise))) { \
  31                          printk(KERN_NOTICE "Further such events for this erase block will not be printed\n"); \
  32                  } \
  33         } \
  34 } while(0)
  35
  36 static uint32_t pseudo_random;
  37
  38 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  39                                   unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s);
  40
  41 /* These helper functions _must_ increase ofs and also do the dirty/used space accounting.
  42  * Returning an error will abort the mount - bad checksums etc. should just mark the space
  43  * as dirty.
  44  */
  45 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  46                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s);
  47 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  48                                  struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s);
  49
  50 static inline int min_free(struct jffs2_sb_info *c)
  51 {
  52         uint32_t min = 2 * sizeof(struct jffs2_raw_inode);
  53 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
  54         if (!jffs2_can_mark_obsolete(c) && min < c->wbuf_pagesize)
  55                 return c->wbuf_pagesize;
  56 #endif
  57         return min;
  58
  59 }
  60
  61 static inline uint32_t EMPTY_SCAN_SIZE(uint32_t sector_size) {
  62         if (sector_size < DEFAULT_EMPTY_SCAN_SIZE)
  63                 return sector_size;
  64         else
  65                 return DEFAULT_EMPTY_SCAN_SIZE;
  66 }
  67
  68 int jffs2_scan_medium(struct jffs2_sb_info *c)
  69 {
  70         int i, ret;
  71         uint32_t empty_blocks = 0, bad_blocks = 0;
  72         unsigned char *flashbuf = NULL;
  73         uint32_t buf_size = 0;
  74         struct jffs2_summary *s = NULL; /* summary info collected by the scan process */
  75 #ifndef __ECOS
  76         size_t pointlen;
  77
  78         if (c->mtd->point) {
  79                 ret = c->mtd->point (c->mtd, 0, c->mtd->size, &pointlen, &flashbuf);
  80                 if (!ret && pointlen < c->mtd->size) {
  81                         /* Don't muck about if it won't let us point to the whole flash */
  82                         D1(printk(KERN_DEBUG "MTD point returned len too short: 0x%zx\n", pointlen));
  83                         c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
  84                         flashbuf = NULL;
  85                 }
  86                 if (ret)
  87                         D1(printk(KERN_DEBUG "MTD point failed %d\n", ret));
  88         }
  89 #endif
  90         if (!flashbuf) {
  91                 /* For NAND it's quicker to read a whole eraseblock at a time,
  92                    apparently */
  93                 if (jffs2_cleanmarker_oob(c))
  94                         buf_size = c->sector_size;
  95                 else
  96                         buf_size = PAGE_SIZE;
  97
  98                 /* Respect kmalloc limitations */
  99                 if (buf_size > 128*1024)
 100                         buf_size = 128*1024;
 101
 102                 D1(printk(KERN_DEBUG "Allocating readbuf of %d bytes\n", buf_size));
 103                 flashbuf = kmalloc(buf_size, GFP_KERNEL);
 104                 if (!flashbuf)
 105                         return -ENOMEM;
 106         }
 107
 108         if (jffs2_sum_active()) {
 109                 s = kmalloc(sizeof(struct jffs2_summary), GFP_KERNEL);
 110                 if (!s) {
 111                         JFFS2_WARNING("Can't allocate memory for summary\n");
 112                         return -ENOMEM;
 113                 }
 114                 memset(s, 0, sizeof(struct jffs2_summary));
 115         }
 116
 117         for (i=0; i<c->nr_blocks; i++) {
 118                 struct jffs2_eraseblock *jeb = &c->blocks[i];
 119
 120                 /* reset summary info for next eraseblock scan */
 121                 jffs2_sum_reset_collected(s);
 122
 123                 ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset),
 124                                                 buf_size, s);
 125
 126                 if (ret < 0)
 127                         goto out;
 128
 129                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 130
 131                 /* Now decide which list to put it on */
 132                 switch(ret) {
 133                 case BLK_STATE_ALLFF:
 134                         /*
 135                          * Empty block.   Since we can't be sure it
 136                          * was entirely erased, we just queue it for erase
 137                          * again.  It will be marked as such when the erase
 138                          * is complete.  Meanwhile we still count it as empty
 139                          * for later checks.
 140                          */
 141                         empty_blocks++;
 142                         list_add(&jeb->list, &c->erase_pending_list);
 143                         c->nr_erasing_blocks++;
 144                         break;
 145
 146                 case BLK_STATE_CLEANMARKER:
 147                         /* Only a CLEANMARKER node is valid */
 148                         if (!jeb->dirty_size) {
 149                                 /* It's actually free */
 150                                 list_add(&jeb->list, &c->free_list);
 151                                 c->nr_free_blocks++;
 152                         } else {
 153                                 /* Dirt */
 154                                 D1(printk(KERN_DEBUG "Adding all-dirty block at 0x%08x to erase_pending_list\n", jeb->offset));
 155                                 list_add(&jeb->list, &c->erase_pending_list);
 156                                 c->nr_erasing_blocks++;
 157                         }
 158                         break;
 159
 160                 case BLK_STATE_CLEAN:
 161                         /* Full (or almost full) of clean data. Clean list */
 162                         list_add(&jeb->list, &c->clean_list);
 163                         break;
 164
 165                 case BLK_STATE_PARTDIRTY:
 166                         /* Some data, but not full. Dirty list. */
 167                         /* We want to remember the block with most free space
 168                         and stick it in the 'nextblock' position to start writing to it. */
 169                         if (jeb->free_size > min_free(c) &&
 170                                         (!c->nextblock || c->nextblock->free_size < jeb->free_size)) {
 171                                 /* Better candidate for the next writes to go to */
 172                                 if (c->nextblock) {
 173                                         c->nextblock->dirty_size += c->nextblock->free_size + c->nextblock->wasted_size;
 174                                         c->dirty_size += c->nextblock->free_size + c->nextblock->wasted_size;
 175                                         c->free_size -= c->nextblock->free_size;
 176                                         c->wasted_size -= c->nextblock->wasted_size;
 177                                         c->nextblock->free_size = c->nextblock->wasted_size = 0;
 178                                         if (VERYDIRTY(c, c->nextblock->dirty_size)) {
 179                                                 list_add(&c->nextblock->list, &c->very_dirty_list);
 180                                         } else {
 181                                                 list_add(&c->nextblock->list, &c->dirty_list);
 182                                         }
 183                                         /* deleting summary information of the old nextblock */
 184                                         jffs2_sum_reset_collected(c->summary);
 185                                 }
 186                                 /* update collected summary infromation for the current nextblock */
 187                                 jffs2_sum_move_collected(c, s);
 188                                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): new nextblock = 0x%08x\n", jeb->offset));
 189                                 c->nextblock = jeb;
 190                         } else {
 191                                 jeb->dirty_size += jeb->free_size + jeb->wasted_size;
 192                                 c->dirty_size += jeb->free_size + jeb->wasted_size;
 193                                 c->free_size -= jeb->free_size;
 194                                 c->wasted_size -= jeb->wasted_size;
 195                                 jeb->free_size = jeb->wasted_size = 0;
 196                                 if (VERYDIRTY(c, jeb->dirty_size)) {
 197                                         list_add(&jeb->list, &c->very_dirty_list);
 198                                 } else {
 199                                         list_add(&jeb->list, &c->dirty_list);
 200                                 }
 201                         }
 202                         break;
 203
 204                 case BLK_STATE_ALLDIRTY:
 205                         /* Nothing valid - not even a clean marker. Needs erasing. */
 206                         /* For now we just put it on the erasing list. We'll start the erases later */
 207                         D1(printk(KERN_NOTICE "JFFS2: Erase block at 0x%08x is not formatted. It will be erased\n", jeb->offset));
 208                         list_add(&jeb->list, &c->erase_pending_list);
 209                         c->nr_erasing_blocks++;
 210                         break;
 211
 212                 case BLK_STATE_BADBLOCK:
 213                         D1(printk(KERN_NOTICE "JFFS2: Block at 0x%08x is bad\n", jeb->offset));
 214                         list_add(&jeb->list, &c->bad_list);
 215                         c->bad_size += c->sector_size;
 216                         c->free_size -= c->sector_size;
 217                         bad_blocks++;
 218                         break;
 219                 default:
 220                         printk(KERN_WARNING "jffs2_scan_medium(): unknown block state\n");
 221                         BUG();
 222                 }
 223         }
 224
 225         if (jffs2_sum_active() && s)
 226                 kfree(s);
 227
 228         /* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
 229         if (c->nextblock && (c->nextblock->dirty_size)) {
 230                 c->nextblock->wasted_size += c->nextblock->dirty_size;
 231                 c->wasted_size += c->nextblock->dirty_size;
 232                 c->dirty_size -= c->nextblock->dirty_size;
 233                 c->nextblock->dirty_size = 0;
 234         }
 235 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 236         if (!jffs2_can_mark_obsolete(c) && c->nextblock && (c->nextblock->free_size % c->wbuf_pagesize)) {
 237                 /* If we're going to start writing into a block which already
 238                    contains data, and the end of the data isn't page-aligned,
 239                    skip a little and align it. */
 240
 241                 uint32_t skip = c->nextblock->free_size % c->wbuf_pagesize;
 242
 243                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): Skipping %d bytes in nextblock to ensure page alignment\n",
 244                           skip));
 245                 c->nextblock->wasted_size += skip;
 246                 c->wasted_size += skip;
 247
 248                 c->nextblock->free_size -= skip;
 249                 c->free_size -= skip;
 250         }
 251 #endif
 252         if (c->nr_erasing_blocks) {
 253                 if ( !c->used_size && ((c->nr_free_blocks+empty_blocks+bad_blocks)!= c->nr_blocks || bad_blocks == c->nr_blocks) ) {
 254                         printk(KERN_NOTICE "Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
 255                         printk(KERN_NOTICE "empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",empty_blocks,bad_blocks,c->nr_blocks);
 256                         ret = -EIO;
 257                         goto out;
 258                 }
 259                 jffs2_erase_pending_trigger(c);
 260         }
 261         ret = 0;
 262  out:
 263         if (buf_size)
 264                 kfree(flashbuf);
 265 #ifndef __ECOS
 266         else
 267                 c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
 268 #endif
 269         return ret;
 270 }
 271
 272 int jffs2_fill_scan_buf (struct jffs2_sb_info *c, void *buf,
 273                                 uint32_t ofs, uint32_t len)
 274 {
 275         int ret;
 276         size_t retlen;
 277
 278         ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
 279         if (ret) {
 280                 D1(printk(KERN_WARNING "mtd->read(0x%x bytes from 0x%x) returned %d\n", len, ofs, ret));
 281                 return ret;
 282         }
 283         if (retlen < len) {
 284                 D1(printk(KERN_WARNING "Read at 0x%x gave only 0x%zx bytes\n", ofs, retlen));
 285                 return -EIO;
 286         }
 287         D2(printk(KERN_DEBUG "Read 0x%x bytes from 0x%08x into buf\n", len, ofs));
 288         D2(printk(KERN_DEBUG "000: %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x\n",
 289                   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]));
 290         return 0;
 291 }
 292
 293 int jffs2_scan_classify_jeb(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
 294 {
 295         if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size
 296                 && (!jeb->first_node || !jeb->first_node->next_phys) )
 297                 return BLK_STATE_CLEANMARKER;
 298
 299         /* move blocks with max 4 byte dirty space to cleanlist */
 300         else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
 301                 c->dirty_size -= jeb->dirty_size;
 302                 c->wasted_size += jeb->dirty_size;
 303                 jeb->wasted_size += jeb->dirty_size;
 304                 jeb->dirty_size = 0;
 305                 return BLK_STATE_CLEAN;
 306         } else if (jeb->used_size || jeb->unchecked_size)
 307                 return BLK_STATE_PARTDIRTY;
 308         else
 309                 return BLK_STATE_ALLDIRTY;
 310 }
 311
 312 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 313                                 unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) {
 314         struct jffs2_unknown_node *node;
 315         struct jffs2_unknown_node crcnode;
 316         struct jffs2_sum_marker *sm;
 317         uint32_t ofs, prevofs;
 318         uint32_t hdr_crc, buf_ofs, buf_len;
 319         int err;
 320         int noise = 0;
 321
 322
 323 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 324         int cleanmarkerfound = 0;
 325 #endif
 326
 327         ofs = jeb->offset;
 328         prevofs = jeb->offset - 1;
 329
 330         D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs));
 331
 332 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 333         if (jffs2_cleanmarker_oob(c)) {
 334                 int ret = jffs2_check_nand_cleanmarker(c, jeb);
 335                 D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n",ret));
 336                 /* Even if it's not found, we still scan to see
 337                    if the block is empty. We use this information
 338                    to decide whether to erase it or not. */
 339                 switch (ret) {
 340                 case 0:         cleanmarkerfound = 1; break;
 341                 case 1:         break;
 342                 case 2:         return BLK_STATE_BADBLOCK;
 343                 case 3:         return BLK_STATE_ALLDIRTY; /* Block has failed to erase min. once */
 344                 default:        return ret;
 345                 }
 346         }
 347 #endif
 348
 349         if (jffs2_sum_active()) {
 350                 sm = kmalloc(sizeof(struct jffs2_sum_marker), GFP_KERNEL);
 351                 if (!sm) {
 352                         return -ENOMEM;
 353                 }
 354
 355                 err = jffs2_fill_scan_buf(c, (unsigned char *) sm, jeb->offset + c->sector_size -
 356                                         sizeof(struct jffs2_sum_marker), sizeof(struct jffs2_sum_marker));
 357                 if (err) {
 358                         kfree(sm);
 359                         return err;
 360                 }
 361
 362                 if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC ) {
 363                         err = jffs2_sum_scan_sumnode(c, jeb, je32_to_cpu(sm->offset), &pseudo_random);
 364                         if (err) {
 365                                 kfree(sm);
 366                                 return err;
 367                         }
 368                 }
 369
 370                 kfree(sm);
 371
 372                 ofs = jeb->offset;
 373                 prevofs = jeb->offset - 1;
 374         }
 375
 376         buf_ofs = jeb->offset;
 377
 378         if (!buf_size) {
 379                 buf_len = c->sector_size;
 380
 381                 if (jffs2_sum_active()) {
 382                         /* must reread because of summary test */
 383                         err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
 384                         if (err)
 385                                 return err;
 386                 }
 387
 388         } else {
 389                 buf_len = EMPTY_SCAN_SIZE(c->sector_size);
 390                 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
 391                 if (err)
 392                         return err;
 393         }
 394
 395         /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
 396         ofs = 0;
 397
 398         /* Scan only 4KiB of 0xFF before declaring it's empty */
 399         while(ofs < EMPTY_SCAN_SIZE(c->sector_size) && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
 400                 ofs += 4;
 401
 402         if (ofs == EMPTY_SCAN_SIZE(c->sector_size)) {
 403 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 404                 if (jffs2_cleanmarker_oob(c)) {
 405                         /* scan oob, take care of cleanmarker */
 406                         int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
 407                         D2(printk(KERN_NOTICE "jffs2_check_oob_empty returned %d\n",ret));
 408                         switch (ret) {
 409                         case 0:         return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
 410                         case 1:         return BLK_STATE_ALLDIRTY;
 411                         default:        return ret;
 412                         }
 413                 }
 414 #endif
 415                 D1(printk(KERN_DEBUG "Block at 0x%08x is empty (erased)\n", jeb->offset));
 416                 if (c->cleanmarker_size == 0)
 417                         return BLK_STATE_CLEANMARKER;   /* don't bother with re-erase */
 418                 else
 419                         return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
 420         }
 421         if (ofs) {
 422                 D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset,
 423                           jeb->offset + ofs));
 424                 DIRTY_SPACE(ofs);
 425         }
 426
 427         /* Now ofs is a complete physical flash offset as it always was... */
 428         ofs += jeb->offset;
 429
 430         noise = 10;
 431
 432         dbg_summary("no summary found in jeb 0x%08x. Apply original scan.\n",jeb->offset);
 433
 434 scan_more:
 435         while(ofs < jeb->offset + c->sector_size) {
 436
 437                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 438
 439                 cond_resched();
 440
 441                 if (ofs & 3) {
 442                         printk(KERN_WARNING "Eep. ofs 0x%08x not word-aligned!\n", ofs);
 443                         ofs = PAD(ofs);
 444                         continue;
 445                 }
 446                 if (ofs == prevofs) {
 447                         printk(KERN_WARNING "ofs 0x%08x has already been seen. Skipping\n", ofs);
 448                         DIRTY_SPACE(4);
 449                         ofs += 4;
 450                         continue;
 451                 }
 452                 prevofs = ofs;
 453
 454                 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
 455                         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),
 456                                   jeb->offset, c->sector_size, ofs, sizeof(*node)));
 457                         DIRTY_SPACE((jeb->offset + c->sector_size)-ofs);
 458                         break;
 459                 }
 460
 461                 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
 462                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 463                         D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
 464                                   sizeof(struct jffs2_unknown_node), buf_len, ofs));
 465                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 466                         if (err)
 467                                 return err;
 468                         buf_ofs = ofs;
 469                 }
 470
 471                 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
 472
 473                 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
 474                         uint32_t inbuf_ofs;
 475                         uint32_t empty_start;
 476
 477                         empty_start = ofs;
 478                         ofs += 4;
 479
 480                         D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs));
 481                 more_empty:
 482                         inbuf_ofs = ofs - buf_ofs;
 483                         while (inbuf_ofs < buf_len) {
 484                                 if (*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff) {
 485                                         printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n",
 486                                                empty_start, ofs);
 487                                         DIRTY_SPACE(ofs-empty_start);
 488                                         goto scan_more;
 489                                 }
 490
 491                                 inbuf_ofs+=4;
 492                                 ofs += 4;
 493                         }
 494                         /* Ran off end. */
 495                         D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs));
 496
 497                         /* If we're only checking the beginning of a block with a cleanmarker,
 498                            bail now */
 499                         if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&
 500                             c->cleanmarker_size && !jeb->dirty_size && !jeb->first_node->next_phys) {
 501                                 D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE(c->sector_size)));
 502                                 return BLK_STATE_CLEANMARKER;
 503                         }
 504
 505                         /* See how much more there is to read in this eraseblock... */
 506                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 507                         if (!buf_len) {
 508                                 /* No more to read. Break out of main loop without marking
 509                                    this range of empty space as dirty (because it's not) */
 510                                 D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block. Treating as free_space\n",
 511                                           empty_start));
 512                                 break;
 513                         }
 514                         D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs));
 515                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 516                         if (err)
 517                                 return err;
 518                         buf_ofs = ofs;
 519                         goto more_empty;
 520                 }
 521
 522                 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
 523                         printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n", ofs);
 524                         DIRTY_SPACE(4);
 525                         ofs += 4;
 526                         continue;
 527                 }
 528                 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
 529                         D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs));
 530                         DIRTY_SPACE(4);
 531                         ofs += 4;
 532                         continue;
 533                 }
 534                 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
 535                         printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08x\n", ofs);
 536                         printk(KERN_WARNING "You cannot use older JFFS2 filesystems with newer kernels\n");
 537                         DIRTY_SPACE(4);
 538                         ofs += 4;
 539                         continue;
 540                 }
 541                 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
 542                         /* OK. We're out of possibilities. Whinge and move on */
 543                         noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n",
 544                                      JFFS2_MAGIC_BITMASK, ofs,
 545                                      je16_to_cpu(node->magic));
 546                         DIRTY_SPACE(4);
 547                         ofs += 4;
 548                         continue;
 549                 }
 550                 /* We seem to have a node of sorts. Check the CRC */
 551                 crcnode.magic = node->magic;
 552                 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
 553                 crcnode.totlen = node->totlen;
 554                 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
 555
 556                 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
 557                         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",
 558                                      ofs, je16_to_cpu(node->magic),
 559                                      je16_to_cpu(node->nodetype),
 560                                      je32_to_cpu(node->totlen),
 561                                      je32_to_cpu(node->hdr_crc),
 562                                      hdr_crc);
 563                         DIRTY_SPACE(4);
 564                         ofs += 4;
 565                         continue;
 566                 }
 567
 568                 if (ofs + je32_to_cpu(node->totlen) >
 569                     jeb->offset + c->sector_size) {
 570                         /* Eep. Node goes over the end of the erase block. */
 571                         printk(KERN_WARNING "Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
 572                                ofs, je32_to_cpu(node->totlen));
 573                         printk(KERN_WARNING "Perhaps the file system was created with the wrong erase size?\n");
 574                         DIRTY_SPACE(4);
 575                         ofs += 4;
 576                         continue;
 577                 }
 578
 579                 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
 580                         /* Wheee. This is an obsoleted node */
 581                         D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs));
 582                         DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 583                         ofs += PAD(je32_to_cpu(node->totlen));
 584                         continue;
 585                 }
 586
 587                 switch(je16_to_cpu(node->nodetype)) {
 588                 case JFFS2_NODETYPE_INODE:
 589                         if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
 590                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 591                                 D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
 592                                           sizeof(struct jffs2_raw_inode), buf_len, ofs));
 593                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 594                                 if (err)
 595                                         return err;
 596                                 buf_ofs = ofs;
 597                                 node = (void *)buf;
 598                         }
 599                         err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs, s);
 600                         if (err) return err;
 601                         ofs += PAD(je32_to_cpu(node->totlen));
 602                         break;
 603
 604                 case JFFS2_NODETYPE_DIRENT:
 605                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 606                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 607                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
 608                                           je32_to_cpu(node->totlen), buf_len, ofs));
 609                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 610                                 if (err)
 611                                         return err;
 612                                 buf_ofs = ofs;
 613                                 node = (void *)buf;
 614                         }
 615                         err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs, s);
 616                         if (err) return err;
 617                         ofs += PAD(je32_to_cpu(node->totlen));
 618                         break;
 619
 620                 case JFFS2_NODETYPE_CLEANMARKER:
 621                         D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs));
 622                         if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
 623                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n",
 624                                        ofs, je32_to_cpu(node->totlen), c->cleanmarker_size);
 625                                 DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
 626                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 627                         } else if (jeb->first_node) {
 628                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n", ofs, jeb->offset);
 629                                 DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
 630                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 631                         } else {
 632                                 struct jffs2_raw_node_ref *marker_ref = jffs2_alloc_raw_node_ref();
 633                                 if (!marker_ref) {
 634                                         printk(KERN_NOTICE "Failed to allocate node ref for clean marker\n");
 635                                         return -ENOMEM;
 636                                 }
 637                                 marker_ref->next_in_ino = NULL;
 638                                 marker_ref->next_phys = NULL;
 639                                 marker_ref->flash_offset = ofs | REF_NORMAL;
 640                                 marker_ref->__totlen = c->cleanmarker_size;
 641                                 jeb->first_node = jeb->last_node = marker_ref;
 642
 643                                 USED_SPACE(PAD(c->cleanmarker_size));
 644                                 ofs += PAD(c->cleanmarker_size);
 645                         }
 646                         break;
 647
 648                 case JFFS2_NODETYPE_PADDING:
 649                         if (jffs2_sum_active())
 650                                 jffs2_sum_add_padding_mem(s, je32_to_cpu(node->totlen));
 651                         DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 652                         ofs += PAD(je32_to_cpu(node->totlen));
 653                         break;
 654
 655                 default:
 656                         switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
 657                         case JFFS2_FEATURE_ROCOMPAT:
 658                                 printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 659                                 c->flags |= JFFS2_SB_FLAG_RO;
 660                                 if (!(jffs2_is_readonly(c)))
 661                                         return -EROFS;
 662                                 DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 663                                 ofs += PAD(je32_to_cpu(node->totlen));
 664                                 break;
 665
 666                         case JFFS2_FEATURE_INCOMPAT:
 667                                 printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 668                                 return -EINVAL;
 669
 670                         case JFFS2_FEATURE_RWCOMPAT_DELETE:
 671                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 672                                 DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 673                                 ofs += PAD(je32_to_cpu(node->totlen));
 674                                 break;
 675
 676                         case JFFS2_FEATURE_RWCOMPAT_COPY:
 677                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 678                                 USED_SPACE(PAD(je32_to_cpu(node->totlen)));
 679                                 ofs += PAD(je32_to_cpu(node->totlen));
 680                                 break;
 681                         }
 682                 }
 683         }
 684
 685         if (jffs2_sum_active()) {
 686                 if (PAD(s->sum_size + JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size) {
 687                         dbg_summary("There is not enough space for "
 688                                 "summary information, disabling for this jeb!\n");
 689                         jffs2_sum_disable_collecting(s);
 690                 }
 691         }
 692
 693         D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x\n", jeb->offset,
 694                   jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size));
 695
 696         /* mark_node_obsolete can add to wasted !! */
 697         if (jeb->wasted_size) {
 698                 jeb->dirty_size += jeb->wasted_size;
 699                 c->dirty_size += jeb->wasted_size;
 700                 c->wasted_size -= jeb->wasted_size;
 701                 jeb->wasted_size = 0;
 702         }
 703
 704         return jffs2_scan_classify_jeb(c, jeb);
 705 }
 706
 707 struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
 708 {
 709         struct jffs2_inode_cache *ic;
 710
 711         ic = jffs2_get_ino_cache(c, ino);
 712         if (ic)
 713                 return ic;
 714
 715         if (ino > c->highest_ino)
 716                 c->highest_ino = ino;
 717
 718         ic = jffs2_alloc_inode_cache();
 719         if (!ic) {
 720                 printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n");
 721                 return NULL;
 722         }
 723         memset(ic, 0, sizeof(*ic));
 724
 725         ic->ino = ino;
 726         ic->nodes = (void *)ic;
 727         jffs2_add_ino_cache(c, ic);
 728         if (ino == 1)
 729                 ic->nlink = 1;
 730         return ic;
 731 }
 732
 733 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 734                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s)
 735 {
 736         struct jffs2_raw_node_ref *raw;
 737         struct jffs2_inode_cache *ic;
 738         uint32_t ino = je32_to_cpu(ri->ino);
 739
 740         D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs));
 741
 742         /* We do very little here now. Just check the ino# to which we should attribute
 743            this node; we can do all the CRC checking etc. later. There's a tradeoff here --
 744            we used to scan the flash once only, reading everything we want from it into
 745            memory, then building all our in-core data structures and freeing the extra
 746            information. Now we allow the first part of the mount to complete a lot quicker,
 747            but we have to go _back_ to the flash in order to finish the CRC checking, etc.
 748            Which means that the _full_ amount of time to get to proper write mode with GC
 749            operational may actually be _longer_ than before. Sucks to be me. */
 750
 751         raw = jffs2_alloc_raw_node_ref();
 752         if (!raw) {
 753                 printk(KERN_NOTICE "jffs2_scan_inode_node(): allocation of node reference failed\n");
 754                 return -ENOMEM;
 755         }
 756
 757         ic = jffs2_get_ino_cache(c, ino);
 758         if (!ic) {
 759                 /* Inocache get failed. Either we read a bogus ino# or it's just genuinely the
 760                    first node we found for this inode. Do a CRC check to protect against the former
 761                    case */
 762                 uint32_t crc = crc32(0, ri, sizeof(*ri)-8);
 763
 764                 if (crc != je32_to_cpu(ri->node_crc)) {
 765                         printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 766                                ofs, je32_to_cpu(ri->node_crc), crc);
 767                         /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
 768                         DIRTY_SPACE(PAD(je32_to_cpu(ri->totlen)));
 769                         jffs2_free_raw_node_ref(raw);
 770                         return 0;
 771                 }
 772                 ic = jffs2_scan_make_ino_cache(c, ino);
 773                 if (!ic) {
 774                         jffs2_free_raw_node_ref(raw);
 775                         return -ENOMEM;
 776                 }
 777         }
 778
 779         /* Wheee. It worked */
 780
 781         raw->flash_offset = ofs | REF_UNCHECKED;
 782         raw->__totlen = PAD(je32_to_cpu(ri->totlen));
 783         raw->next_phys = NULL;
 784         raw->next_in_ino = ic->nodes;
 785
 786         ic->nodes = raw;
 787         if (!jeb->first_node)
 788                 jeb->first_node = raw;
 789         if (jeb->last_node)
 790                 jeb->last_node->next_phys = raw;
 791         jeb->last_node = raw;
 792
 793         D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
 794                   je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
 795                   je32_to_cpu(ri->offset),
 796                   je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize)));
 797
 798         pseudo_random += je32_to_cpu(ri->version);
 799
 800         UNCHECKED_SPACE(PAD(je32_to_cpu(ri->totlen)));
 801
 802         if (jffs2_sum_active()) {
 803                 jffs2_sum_add_inode_mem(s, ri, ofs - jeb->offset);
 804         }
 805
 806         return 0;
 807 }
 808
 809 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 810                                   struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s)
 811 {
 812         struct jffs2_raw_node_ref *raw;
 813         struct jffs2_full_dirent *fd;
 814         struct jffs2_inode_cache *ic;
 815         uint32_t crc;
 816
 817         D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs));
 818
 819         /* We don't get here unless the node is still valid, so we don't have to
 820            mask in the ACCURATE bit any more. */
 821         crc = crc32(0, rd, sizeof(*rd)-8);
 822
 823         if (crc != je32_to_cpu(rd->node_crc)) {
 824                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 825                        ofs, je32_to_cpu(rd->node_crc), crc);
 826                 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
 827                 DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
 828                 return 0;
 829         }
 830
 831         pseudo_random += je32_to_cpu(rd->version);
 832
 833         fd = jffs2_alloc_full_dirent(rd->nsize+1);
 834         if (!fd) {
 835                 return -ENOMEM;
 836         }
 837         memcpy(&fd->name, rd->name, rd->nsize);
 838         fd->name[rd->nsize] = 0;
 839
 840         crc = crc32(0, fd->name, rd->nsize);
 841         if (crc != je32_to_cpu(rd->name_crc)) {
 842                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 843                        ofs, je32_to_cpu(rd->name_crc), crc);
 844                 D1(printk(KERN_NOTICE "Name for which CRC failed is (now) '%s', ino #%d\n", fd->name, je32_to_cpu(rd->ino)));
 845                 jffs2_free_full_dirent(fd);
 846                 /* FIXME: Why do we believe totlen? */
 847                 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
 848                 DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
 849                 return 0;
 850         }
 851         raw = jffs2_alloc_raw_node_ref();
 852         if (!raw) {
 853                 jffs2_free_full_dirent(fd);
 854                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): allocation of node reference failed\n");
 855                 return -ENOMEM;
 856         }
 857         ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
 858         if (!ic) {
 859                 jffs2_free_full_dirent(fd);
 860                 jffs2_free_raw_node_ref(raw);
 861                 return -ENOMEM;
 862         }
 863
 864         raw->__totlen = PAD(je32_to_cpu(rd->totlen));
 865         raw->flash_offset = ofs | REF_PRISTINE;
 866         raw->next_phys = NULL;
 867         raw->next_in_ino = ic->nodes;
 868         ic->nodes = raw;
 869         if (!jeb->first_node)
 870                 jeb->first_node = raw;
 871         if (jeb->last_node)
 872                 jeb->last_node->next_phys = raw;
 873         jeb->last_node = raw;
 874
 875         fd->raw = raw;
 876         fd->next = NULL;
 877         fd->version = je32_to_cpu(rd->version);
 878         fd->ino = je32_to_cpu(rd->ino);
 879         fd->nhash = full_name_hash(fd->name, rd->nsize);
 880         fd->type = rd->type;
 881         USED_SPACE(PAD(je32_to_cpu(rd->totlen)));
 882         jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
 883
 884         if (jffs2_sum_active()) {
 885                 jffs2_sum_add_dirent_mem(s, rd, ofs - jeb->offset);
 886         }
 887
 888         return 0;
 889 }
 890
 891 static int count_list(struct list_head *l)
 892 {
 893         uint32_t count = 0;
 894         struct list_head *tmp;
 895
 896         list_for_each(tmp, l) {
 897                 count++;
 898         }
 899         return count;
 900 }
 901
 902 /* Note: This breaks if list_empty(head). I don't care. You
 903    might, if you copy this code and use it elsewhere :) */
 904 static void rotate_list(struct list_head *head, uint32_t count)
 905 {
 906         struct list_head *n = head->next;
 907
 908         list_del(head);
 909         while(count--) {
 910                 n = n->next;
 911         }
 912         list_add(head, n);
 913 }
 914
 915 void jffs2_rotate_lists(struct jffs2_sb_info *c)
 916 {
 917         uint32_t x;
 918         uint32_t rotateby;
 919
 920         x = count_list(&c->clean_list);
 921         if (x) {
 922                 rotateby = pseudo_random % x;
 923                 rotate_list((&c->clean_list), rotateby);
 924         }
 925
 926         x = count_list(&c->very_dirty_list);
 927         if (x) {
 928                 rotateby = pseudo_random % x;
 929                 rotate_list((&c->very_dirty_list), rotateby);
 930         }
 931
 932         x = count_list(&c->dirty_list);
 933         if (x) {
 934                 rotateby = pseudo_random % x;
 935                 rotate_list((&c->dirty_list), rotateby);
 936         }
 937
 938         x = count_list(&c->erasable_list);
 939         if (x) {
 940                 rotateby = pseudo_random % x;
 941                 rotate_list((&c->erasable_list), rotateby);
 942         }
 943
 944         if (c->nr_erasing_blocks) {
 945                 rotateby = pseudo_random % c->nr_erasing_blocks;
 946                 rotate_list((&c->erase_pending_list), rotateby);
 947         }
 948
 949         if (c->nr_free_blocks) {
 950                 rotateby = pseudo_random % c->nr_free_blocks;
 951                 rotate_list((&c->free_list), rotateby);
 952         }
 953 }