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->wbuf_pagesize && 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         return 0;
 288 }
 289
 290 int jffs2_scan_classify_jeb(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
 291 {
 292         if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size
 293                 && (!jeb->first_node || !jeb->first_node->next_phys) )
 294                 return BLK_STATE_CLEANMARKER;
 295
 296         /* move blocks with max 4 byte dirty space to cleanlist */
 297         else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
 298                 c->dirty_size -= jeb->dirty_size;
 299                 c->wasted_size += jeb->dirty_size;
 300                 jeb->wasted_size += jeb->dirty_size;
 301                 jeb->dirty_size = 0;
 302                 return BLK_STATE_CLEAN;
 303         } else if (jeb->used_size || jeb->unchecked_size)
 304                 return BLK_STATE_PARTDIRTY;
 305         else
 306                 return BLK_STATE_ALLDIRTY;
 307 }
 308
 309 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 310                                 unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) {
 311         struct jffs2_unknown_node *node;
 312         struct jffs2_unknown_node crcnode;
 313         struct jffs2_sum_marker *sm;
 314         uint32_t ofs, prevofs;
 315         uint32_t hdr_crc, buf_ofs, buf_len;
 316         int err;
 317         int noise = 0;
 318
 319
 320 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 321         int cleanmarkerfound = 0;
 322 #endif
 323
 324         ofs = jeb->offset;
 325         prevofs = jeb->offset - 1;
 326
 327         D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs));
 328
 329 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 330         if (jffs2_cleanmarker_oob(c)) {
 331                 int ret = jffs2_check_nand_cleanmarker(c, jeb);
 332                 D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n",ret));
 333                 /* Even if it's not found, we still scan to see
 334                    if the block is empty. We use this information
 335                    to decide whether to erase it or not. */
 336                 switch (ret) {
 337                 case 0:         cleanmarkerfound = 1; break;
 338                 case 1:         break;
 339                 case 2:         return BLK_STATE_BADBLOCK;
 340                 case 3:         return BLK_STATE_ALLDIRTY; /* Block has failed to erase min. once */
 341                 default:        return ret;
 342                 }
 343         }
 344 #endif
 345
 346         if (jffs2_sum_active()) {
 347                 sm = kmalloc(sizeof(struct jffs2_sum_marker), GFP_KERNEL);
 348                 if (!sm) {
 349                         return -ENOMEM;
 350                 }
 351
 352                 err = jffs2_fill_scan_buf(c, (unsigned char *) sm, jeb->offset + c->sector_size -
 353                                         sizeof(struct jffs2_sum_marker), sizeof(struct jffs2_sum_marker));
 354                 if (err) {
 355                         kfree(sm);
 356                         return err;
 357                 }
 358
 359                 if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC ) {
 360                         err = jffs2_sum_scan_sumnode(c, jeb, je32_to_cpu(sm->offset), &pseudo_random);
 361                         if (err) {
 362                                 kfree(sm);
 363                                 return err;
 364                         }
 365                 }
 366
 367                 kfree(sm);
 368
 369                 ofs = jeb->offset;
 370                 prevofs = jeb->offset - 1;
 371         }
 372
 373         buf_ofs = jeb->offset;
 374
 375         if (!buf_size) {
 376                 buf_len = c->sector_size;
 377
 378                 if (jffs2_sum_active()) {
 379                         /* must reread because of summary test */
 380                         err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
 381                         if (err)
 382                                 return err;
 383                 }
 384
 385         } else {
 386                 buf_len = EMPTY_SCAN_SIZE(c->sector_size);
 387                 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
 388                 if (err)
 389                         return err;
 390         }
 391
 392         /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
 393         ofs = 0;
 394
 395         /* Scan only 4KiB of 0xFF before declaring it's empty */
 396         while(ofs < EMPTY_SCAN_SIZE(c->sector_size) && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
 397                 ofs += 4;
 398
 399         if (ofs == EMPTY_SCAN_SIZE(c->sector_size)) {
 400 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 401                 if (jffs2_cleanmarker_oob(c)) {
 402                         /* scan oob, take care of cleanmarker */
 403                         int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
 404                         D2(printk(KERN_NOTICE "jffs2_check_oob_empty returned %d\n",ret));
 405                         switch (ret) {
 406                         case 0:         return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
 407                         case 1:         return BLK_STATE_ALLDIRTY;
 408                         default:        return ret;
 409                         }
 410                 }
 411 #endif
 412                 D1(printk(KERN_DEBUG "Block at 0x%08x is empty (erased)\n", jeb->offset));
 413                 if (c->cleanmarker_size == 0)
 414                         return BLK_STATE_CLEANMARKER;   /* don't bother with re-erase */
 415                 else
 416                         return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
 417         }
 418         if (ofs) {
 419                 D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset,
 420                           jeb->offset + ofs));
 421                 DIRTY_SPACE(ofs);
 422         }
 423
 424         /* Now ofs is a complete physical flash offset as it always was... */
 425         ofs += jeb->offset;
 426
 427         noise = 10;
 428
 429         dbg_summary("no summary found in jeb 0x%08x. Apply original scan.\n",jeb->offset);
 430
 431 scan_more:
 432         while(ofs < jeb->offset + c->sector_size) {
 433
 434                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 435
 436                 cond_resched();
 437
 438                 if (ofs & 3) {
 439                         printk(KERN_WARNING "Eep. ofs 0x%08x not word-aligned!\n", ofs);
 440                         ofs = PAD(ofs);
 441                         continue;
 442                 }
 443                 if (ofs == prevofs) {
 444                         printk(KERN_WARNING "ofs 0x%08x has already been seen. Skipping\n", ofs);
 445                         DIRTY_SPACE(4);
 446                         ofs += 4;
 447                         continue;
 448                 }
 449                 prevofs = ofs;
 450
 451                 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
 452                         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),
 453                                   jeb->offset, c->sector_size, ofs, sizeof(*node)));
 454                         DIRTY_SPACE((jeb->offset + c->sector_size)-ofs);
 455                         break;
 456                 }
 457
 458                 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
 459                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 460                         D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
 461                                   sizeof(struct jffs2_unknown_node), buf_len, ofs));
 462                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 463                         if (err)
 464                                 return err;
 465                         buf_ofs = ofs;
 466                 }
 467
 468                 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
 469
 470                 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
 471                         uint32_t inbuf_ofs;
 472                         uint32_t empty_start;
 473
 474                         empty_start = ofs;
 475                         ofs += 4;
 476
 477                         D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs));
 478                 more_empty:
 479                         inbuf_ofs = ofs - buf_ofs;
 480                         while (inbuf_ofs < buf_len) {
 481                                 if (*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff) {
 482                                         printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n",
 483                                                empty_start, ofs);
 484                                         DIRTY_SPACE(ofs-empty_start);
 485                                         goto scan_more;
 486                                 }
 487
 488                                 inbuf_ofs+=4;
 489                                 ofs += 4;
 490                         }
 491                         /* Ran off end. */
 492                         D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs));
 493
 494                         /* If we're only checking the beginning of a block with a cleanmarker,
 495                            bail now */
 496                         if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&
 497                             c->cleanmarker_size && !jeb->dirty_size && !jeb->first_node->next_phys) {
 498                                 D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE(c->sector_size)));
 499                                 return BLK_STATE_CLEANMARKER;
 500                         }
 501
 502                         /* See how much more there is to read in this eraseblock... */
 503                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 504                         if (!buf_len) {
 505                                 /* No more to read. Break out of main loop without marking
 506                                    this range of empty space as dirty (because it's not) */
 507                                 D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block. Treating as free_space\n",
 508                                           empty_start));
 509                                 break;
 510                         }
 511                         D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs));
 512                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 513                         if (err)
 514                                 return err;
 515                         buf_ofs = ofs;
 516                         goto more_empty;
 517                 }
 518
 519                 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
 520                         printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n", ofs);
 521                         DIRTY_SPACE(4);
 522                         ofs += 4;
 523                         continue;
 524                 }
 525                 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
 526                         D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs));
 527                         DIRTY_SPACE(4);
 528                         ofs += 4;
 529                         continue;
 530                 }
 531                 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
 532                         printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08x\n", ofs);
 533                         printk(KERN_WARNING "You cannot use older JFFS2 filesystems with newer kernels\n");
 534                         DIRTY_SPACE(4);
 535                         ofs += 4;
 536                         continue;
 537                 }
 538                 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
 539                         /* OK. We're out of possibilities. Whinge and move on */
 540                         noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n",
 541                                      JFFS2_MAGIC_BITMASK, ofs,
 542                                      je16_to_cpu(node->magic));
 543                         DIRTY_SPACE(4);
 544                         ofs += 4;
 545                         continue;
 546                 }
 547                 /* We seem to have a node of sorts. Check the CRC */
 548                 crcnode.magic = node->magic;
 549                 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
 550                 crcnode.totlen = node->totlen;
 551                 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
 552
 553                 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
 554                         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",
 555                                      ofs, je16_to_cpu(node->magic),
 556                                      je16_to_cpu(node->nodetype),
 557                                      je32_to_cpu(node->totlen),
 558                                      je32_to_cpu(node->hdr_crc),
 559                                      hdr_crc);
 560                         DIRTY_SPACE(4);
 561                         ofs += 4;
 562                         continue;
 563                 }
 564
 565                 if (ofs + je32_to_cpu(node->totlen) >
 566                     jeb->offset + c->sector_size) {
 567                         /* Eep. Node goes over the end of the erase block. */
 568                         printk(KERN_WARNING "Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
 569                                ofs, je32_to_cpu(node->totlen));
 570                         printk(KERN_WARNING "Perhaps the file system was created with the wrong erase size?\n");
 571                         DIRTY_SPACE(4);
 572                         ofs += 4;
 573                         continue;
 574                 }
 575
 576                 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
 577                         /* Wheee. This is an obsoleted node */
 578                         D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs));
 579                         DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 580                         ofs += PAD(je32_to_cpu(node->totlen));
 581                         continue;
 582                 }
 583
 584                 switch(je16_to_cpu(node->nodetype)) {
 585                 case JFFS2_NODETYPE_INODE:
 586                         if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
 587                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 588                                 D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
 589                                           sizeof(struct jffs2_raw_inode), buf_len, ofs));
 590                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 591                                 if (err)
 592                                         return err;
 593                                 buf_ofs = ofs;
 594                                 node = (void *)buf;
 595                         }
 596                         err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs, s);
 597                         if (err) return err;
 598                         ofs += PAD(je32_to_cpu(node->totlen));
 599                         break;
 600
 601                 case JFFS2_NODETYPE_DIRENT:
 602                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 603                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 604                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
 605                                           je32_to_cpu(node->totlen), buf_len, ofs));
 606                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 607                                 if (err)
 608                                         return err;
 609                                 buf_ofs = ofs;
 610                                 node = (void *)buf;
 611                         }
 612                         err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs, s);
 613                         if (err) return err;
 614                         ofs += PAD(je32_to_cpu(node->totlen));
 615                         break;
 616
 617                 case JFFS2_NODETYPE_CLEANMARKER:
 618                         D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs));
 619                         if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
 620                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n",
 621                                        ofs, je32_to_cpu(node->totlen), c->cleanmarker_size);
 622                                 DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
 623                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 624                         } else if (jeb->first_node) {
 625                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n", ofs, jeb->offset);
 626                                 DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
 627                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 628                         } else {
 629                                 struct jffs2_raw_node_ref *marker_ref = jffs2_alloc_raw_node_ref();
 630                                 if (!marker_ref) {
 631                                         printk(KERN_NOTICE "Failed to allocate node ref for clean marker\n");
 632                                         return -ENOMEM;
 633                                 }
 634                                 marker_ref->next_in_ino = NULL;
 635                                 marker_ref->next_phys = NULL;
 636                                 marker_ref->flash_offset = ofs | REF_NORMAL;
 637                                 marker_ref->__totlen = c->cleanmarker_size;
 638                                 jeb->first_node = jeb->last_node = marker_ref;
 639
 640                                 USED_SPACE(PAD(c->cleanmarker_size));
 641                                 ofs += PAD(c->cleanmarker_size);
 642                         }
 643                         break;
 644
 645                 case JFFS2_NODETYPE_PADDING:
 646                         if (jffs2_sum_active())
 647                                 jffs2_sum_add_padding_mem(s, je32_to_cpu(node->totlen));
 648                         DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 649                         ofs += PAD(je32_to_cpu(node->totlen));
 650                         break;
 651
 652                 default:
 653                         switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
 654                         case JFFS2_FEATURE_ROCOMPAT:
 655                                 printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 656                                 c->flags |= JFFS2_SB_FLAG_RO;
 657                                 if (!(jffs2_is_readonly(c)))
 658                                         return -EROFS;
 659                                 DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 660                                 ofs += PAD(je32_to_cpu(node->totlen));
 661                                 break;
 662
 663                         case JFFS2_FEATURE_INCOMPAT:
 664                                 printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 665                                 return -EINVAL;
 666
 667                         case JFFS2_FEATURE_RWCOMPAT_DELETE:
 668                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 669                                 DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 670                                 ofs += PAD(je32_to_cpu(node->totlen));
 671                                 break;
 672
 673                         case JFFS2_FEATURE_RWCOMPAT_COPY:
 674                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 675                                 USED_SPACE(PAD(je32_to_cpu(node->totlen)));
 676                                 ofs += PAD(je32_to_cpu(node->totlen));
 677                                 break;
 678                         }
 679                 }
 680         }
 681
 682         if (jffs2_sum_active()) {
 683                 if (PAD(s->sum_size + JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size) {
 684                         dbg_summary("There is not enough space for "
 685                                 "summary information, disabling for this jeb!\n");
 686                         jffs2_sum_disable_collecting(s);
 687                 }
 688         }
 689
 690         D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x\n", jeb->offset,
 691                   jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size));
 692
 693         /* mark_node_obsolete can add to wasted !! */
 694         if (jeb->wasted_size) {
 695                 jeb->dirty_size += jeb->wasted_size;
 696                 c->dirty_size += jeb->wasted_size;
 697                 c->wasted_size -= jeb->wasted_size;
 698                 jeb->wasted_size = 0;
 699         }
 700
 701         return jffs2_scan_classify_jeb(c, jeb);
 702 }
 703
 704 struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
 705 {
 706         struct jffs2_inode_cache *ic;
 707
 708         ic = jffs2_get_ino_cache(c, ino);
 709         if (ic)
 710                 return ic;
 711
 712         if (ino > c->highest_ino)
 713                 c->highest_ino = ino;
 714
 715         ic = jffs2_alloc_inode_cache();
 716         if (!ic) {
 717                 printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n");
 718                 return NULL;
 719         }
 720         memset(ic, 0, sizeof(*ic));
 721
 722         ic->ino = ino;
 723         ic->nodes = (void *)ic;
 724         jffs2_add_ino_cache(c, ic);
 725         if (ino == 1)
 726                 ic->nlink = 1;
 727         return ic;
 728 }
 729
 730 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 731                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s)
 732 {
 733         struct jffs2_raw_node_ref *raw;
 734         struct jffs2_inode_cache *ic;
 735         uint32_t ino = je32_to_cpu(ri->ino);
 736
 737         D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs));
 738
 739         /* We do very little here now. Just check the ino# to which we should attribute
 740            this node; we can do all the CRC checking etc. later. There's a tradeoff here --
 741            we used to scan the flash once only, reading everything we want from it into
 742            memory, then building all our in-core data structures and freeing the extra
 743            information. Now we allow the first part of the mount to complete a lot quicker,
 744            but we have to go _back_ to the flash in order to finish the CRC checking, etc.
 745            Which means that the _full_ amount of time to get to proper write mode with GC
 746            operational may actually be _longer_ than before. Sucks to be me. */
 747
 748         raw = jffs2_alloc_raw_node_ref();
 749         if (!raw) {
 750                 printk(KERN_NOTICE "jffs2_scan_inode_node(): allocation of node reference failed\n");
 751                 return -ENOMEM;
 752         }
 753
 754         ic = jffs2_get_ino_cache(c, ino);
 755         if (!ic) {
 756                 /* Inocache get failed. Either we read a bogus ino# or it's just genuinely the
 757                    first node we found for this inode. Do a CRC check to protect against the former
 758                    case */
 759                 uint32_t crc = crc32(0, ri, sizeof(*ri)-8);
 760
 761                 if (crc != je32_to_cpu(ri->node_crc)) {
 762                         printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 763                                ofs, je32_to_cpu(ri->node_crc), crc);
 764                         /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
 765                         DIRTY_SPACE(PAD(je32_to_cpu(ri->totlen)));
 766                         jffs2_free_raw_node_ref(raw);
 767                         return 0;
 768                 }
 769                 ic = jffs2_scan_make_ino_cache(c, ino);
 770                 if (!ic) {
 771                         jffs2_free_raw_node_ref(raw);
 772                         return -ENOMEM;
 773                 }
 774         }
 775
 776         /* Wheee. It worked */
 777
 778         raw->flash_offset = ofs | REF_UNCHECKED;
 779         raw->__totlen = PAD(je32_to_cpu(ri->totlen));
 780         raw->next_phys = NULL;
 781         raw->next_in_ino = ic->nodes;
 782
 783         ic->nodes = raw;
 784         if (!jeb->first_node)
 785                 jeb->first_node = raw;
 786         if (jeb->last_node)
 787                 jeb->last_node->next_phys = raw;
 788         jeb->last_node = raw;
 789
 790         D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
 791                   je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
 792                   je32_to_cpu(ri->offset),
 793                   je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize)));
 794
 795         pseudo_random += je32_to_cpu(ri->version);
 796
 797         UNCHECKED_SPACE(PAD(je32_to_cpu(ri->totlen)));
 798
 799         if (jffs2_sum_active()) {
 800                 jffs2_sum_add_inode_mem(s, ri, ofs - jeb->offset);
 801         }
 802
 803         return 0;
 804 }
 805
 806 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 807                                   struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s)
 808 {
 809         struct jffs2_raw_node_ref *raw;
 810         struct jffs2_full_dirent *fd;
 811         struct jffs2_inode_cache *ic;
 812         uint32_t crc;
 813
 814         D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs));
 815
 816         /* We don't get here unless the node is still valid, so we don't have to
 817            mask in the ACCURATE bit any more. */
 818         crc = crc32(0, rd, sizeof(*rd)-8);
 819
 820         if (crc != je32_to_cpu(rd->node_crc)) {
 821                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 822                        ofs, je32_to_cpu(rd->node_crc), crc);
 823                 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
 824                 DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
 825                 return 0;
 826         }
 827
 828         pseudo_random += je32_to_cpu(rd->version);
 829
 830         fd = jffs2_alloc_full_dirent(rd->nsize+1);
 831         if (!fd) {
 832                 return -ENOMEM;
 833         }
 834         memcpy(&fd->name, rd->name, rd->nsize);
 835         fd->name[rd->nsize] = 0;
 836
 837         crc = crc32(0, fd->name, rd->nsize);
 838         if (crc != je32_to_cpu(rd->name_crc)) {
 839                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 840                        ofs, je32_to_cpu(rd->name_crc), crc);
 841                 D1(printk(KERN_NOTICE "Name for which CRC failed is (now) '%s', ino #%d\n", fd->name, je32_to_cpu(rd->ino)));
 842                 jffs2_free_full_dirent(fd);
 843                 /* FIXME: Why do we believe totlen? */
 844                 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
 845                 DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
 846                 return 0;
 847         }
 848         raw = jffs2_alloc_raw_node_ref();
 849         if (!raw) {
 850                 jffs2_free_full_dirent(fd);
 851                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): allocation of node reference failed\n");
 852                 return -ENOMEM;
 853         }
 854         ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
 855         if (!ic) {
 856                 jffs2_free_full_dirent(fd);
 857                 jffs2_free_raw_node_ref(raw);
 858                 return -ENOMEM;
 859         }
 860
 861         raw->__totlen = PAD(je32_to_cpu(rd->totlen));
 862         raw->flash_offset = ofs | REF_PRISTINE;
 863         raw->next_phys = NULL;
 864         raw->next_in_ino = ic->nodes;
 865         ic->nodes = raw;
 866         if (!jeb->first_node)
 867                 jeb->first_node = raw;
 868         if (jeb->last_node)
 869                 jeb->last_node->next_phys = raw;
 870         jeb->last_node = raw;
 871
 872         fd->raw = raw;
 873         fd->next = NULL;
 874         fd->version = je32_to_cpu(rd->version);
 875         fd->ino = je32_to_cpu(rd->ino);
 876         fd->nhash = full_name_hash(fd->name, rd->nsize);
 877         fd->type = rd->type;
 878         USED_SPACE(PAD(je32_to_cpu(rd->totlen)));
 879         jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
 880
 881         if (jffs2_sum_active()) {
 882                 jffs2_sum_add_dirent_mem(s, rd, ofs - jeb->offset);
 883         }
 884
 885         return 0;
 886 }
 887
 888 static int count_list(struct list_head *l)
 889 {
 890         uint32_t count = 0;
 891         struct list_head *tmp;
 892
 893         list_for_each(tmp, l) {
 894                 count++;
 895         }
 896         return count;
 897 }
 898
 899 /* Note: This breaks if list_empty(head). I don't care. You
 900    might, if you copy this code and use it elsewhere :) */
 901 static void rotate_list(struct list_head *head, uint32_t count)
 902 {
 903         struct list_head *n = head->next;
 904
 905         list_del(head);
 906         while(count--) {
 907                 n = n->next;
 908         }
 909         list_add(head, n);
 910 }
 911
 912 void jffs2_rotate_lists(struct jffs2_sb_info *c)
 913 {
 914         uint32_t x;
 915         uint32_t rotateby;
 916
 917         x = count_list(&c->clean_list);
 918         if (x) {
 919                 rotateby = pseudo_random % x;
 920                 rotate_list((&c->clean_list), rotateby);
 921         }
 922
 923         x = count_list(&c->very_dirty_list);
 924         if (x) {
 925                 rotateby = pseudo_random % x;
 926                 rotate_list((&c->very_dirty_list), rotateby);
 927         }
 928
 929         x = count_list(&c->dirty_list);
 930         if (x) {
 931                 rotateby = pseudo_random % x;
 932                 rotate_list((&c->dirty_list), rotateby);
 933         }
 934
 935         x = count_list(&c->erasable_list);
 936         if (x) {
 937                 rotateby = pseudo_random % x;
 938                 rotate_list((&c->erasable_list), rotateby);
 939         }
 940
 941         if (c->nr_erasing_blocks) {
 942                 rotateby = pseudo_random % c->nr_erasing_blocks;
 943                 rotate_list((&c->erase_pending_list), rotateby);
 944         }
 945
 946         if (c->nr_free_blocks) {
 947                 rotateby = pseudo_random % c->nr_free_blocks;
 948                 rotate_list((&c->free_list), rotateby);
 949         }
 950 }