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 1.119 2005/02/17 17:51:13 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
  22 #define DEFAULT_EMPTY_SCAN_SIZE 1024
  23
  24 #define DIRTY_SPACE(x) do { typeof(x) _x = (x); \
  25                 c->free_size -= _x; c->dirty_size += _x; \
  26                 jeb->free_size -= _x ; jeb->dirty_size += _x; \
  27                 }while(0)
  28 #define USED_SPACE(x) do { typeof(x) _x = (x); \
  29                 c->free_size -= _x; c->used_size += _x; \
  30                 jeb->free_size -= _x ; jeb->used_size += _x; \
  31                 }while(0)
  32 #define UNCHECKED_SPACE(x) do { typeof(x) _x = (x); \
  33                 c->free_size -= _x; c->unchecked_size += _x; \
  34                 jeb->free_size -= _x ; jeb->unchecked_size += _x; \
  35                 }while(0)
  36
  37 #define noisy_printk(noise, args...) do { \
  38         if (*(noise)) { \
  39                 printk(KERN_NOTICE args); \
  40                  (*(noise))--; \
  41                  if (!(*(noise))) { \
  42                          printk(KERN_NOTICE "Further such events for this erase block will not be printed\n"); \
  43                  } \
  44         } \
  45 } while(0)
  46
  47 static uint32_t pseudo_random;
  48
  49 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  50                                   unsigned char *buf, uint32_t buf_size);
  51
  52 /* These helper functions _must_ increase ofs and also do the dirty/used space accounting.
  53  * Returning an error will abort the mount - bad checksums etc. should just mark the space
  54  * as dirty.
  55  */
  56 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  57                                  struct jffs2_raw_inode *ri, uint32_t ofs);
  58 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  59                                  struct jffs2_raw_dirent *rd, uint32_t ofs);
  60
  61 #define BLK_STATE_ALLFF         0
  62 #define BLK_STATE_CLEAN         1
  63 #define BLK_STATE_PARTDIRTY     2
  64 #define BLK_STATE_CLEANMARKER   3
  65 #define BLK_STATE_ALLDIRTY      4
  66 #define BLK_STATE_BADBLOCK      5
  67
  68 static inline int min_free(struct jffs2_sb_info *c)
  69 {
  70         uint32_t min = 2 * sizeof(struct jffs2_raw_inode);
  71 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
  72         if (!jffs2_can_mark_obsolete(c) && min < c->wbuf_pagesize)
  73                 return c->wbuf_pagesize;
  74 #endif
  75         return min;
  76
  77 }
  78
  79 static inline uint32_t EMPTY_SCAN_SIZE(uint32_t sector_size) {
  80         if (sector_size < DEFAULT_EMPTY_SCAN_SIZE)
  81                 return sector_size;
  82         else
  83                 return DEFAULT_EMPTY_SCAN_SIZE;
  84 }
  85
  86 int jffs2_scan_medium(struct jffs2_sb_info *c)
  87 {
  88         int i, ret;
  89         uint32_t empty_blocks = 0, bad_blocks = 0;
  90         unsigned char *flashbuf = NULL;
  91         uint32_t buf_size = 0;
  92 #ifndef __ECOS
  93         size_t pointlen;
  94
  95         if (c->mtd->point) {
  96                 ret = c->mtd->point (c->mtd, 0, c->mtd->size, &pointlen, &flashbuf);
  97                 if (!ret && pointlen < c->mtd->size) {
  98                         /* Don't muck about if it won't let us point to the whole flash */
  99                         D1(printk(KERN_DEBUG "MTD point returned len too short: 0x%zx\n", pointlen));
 100                         c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
 101                         flashbuf = NULL;
 102                 }
 103                 if (ret)
 104                         D1(printk(KERN_DEBUG "MTD point failed %d\n", ret));
 105         }
 106 #endif
 107         if (!flashbuf) {
 108                 /* For NAND it's quicker to read a whole eraseblock at a time,
 109                    apparently */
 110                 if (jffs2_cleanmarker_oob(c))
 111                         buf_size = c->sector_size;
 112                 else
 113                         buf_size = PAGE_SIZE;
 114
 115                 /* Respect kmalloc limitations */
 116                 if (buf_size > 128*1024)
 117                         buf_size = 128*1024;
 118
 119                 D1(printk(KERN_DEBUG "Allocating readbuf of %d bytes\n", buf_size));
 120                 flashbuf = kmalloc(buf_size, GFP_KERNEL);
 121                 if (!flashbuf)
 122                         return -ENOMEM;
 123         }
 124
 125         for (i=0; i<c->nr_blocks; i++) {
 126                 struct jffs2_eraseblock *jeb = &c->blocks[i];
 127
 128                 ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset), buf_size);
 129
 130                 if (ret < 0)
 131                         goto out;
 132
 133                 ACCT_PARANOIA_CHECK(jeb);
 134
 135                 /* Now decide which list to put it on */
 136                 switch(ret) {
 137                 case BLK_STATE_ALLFF:
 138                         /*
 139                          * Empty block.   Since we can't be sure it
 140                          * was entirely erased, we just queue it for erase
 141                          * again.  It will be marked as such when the erase
 142                          * is complete.  Meanwhile we still count it as empty
 143                          * for later checks.
 144                          */
 145                         empty_blocks++;
 146                         list_add(&jeb->list, &c->erase_pending_list);
 147                         c->nr_erasing_blocks++;
 148                         break;
 149
 150                 case BLK_STATE_CLEANMARKER:
 151                         /* Only a CLEANMARKER node is valid */
 152                         if (!jeb->dirty_size) {
 153                                 /* It's actually free */
 154                                 list_add(&jeb->list, &c->free_list);
 155                                 c->nr_free_blocks++;
 156                         } else {
 157                                 /* Dirt */
 158                                 D1(printk(KERN_DEBUG "Adding all-dirty block at 0x%08x to erase_pending_list\n", jeb->offset));
 159                                 list_add(&jeb->list, &c->erase_pending_list);
 160                                 c->nr_erasing_blocks++;
 161                         }
 162                         break;
 163
 164                 case BLK_STATE_CLEAN:
 165                         /* Full (or almost full) of clean data. Clean list */
 166                         list_add(&jeb->list, &c->clean_list);
 167                         break;
 168
 169                 case BLK_STATE_PARTDIRTY:
 170                         /* Some data, but not full. Dirty list. */
 171                         /* We want to remember the block with most free space
 172                            and stick it in the 'nextblock' position to start writing to it. */
 173                         if (jeb->free_size > min_free(c) &&
 174                             (!c->nextblock || c->nextblock->free_size < jeb->free_size)) {
 175                                 /* Better candidate for the next writes to go to */
 176                                 if (c->nextblock) {
 177                                         c->nextblock->dirty_size += c->nextblock->free_size + c->nextblock->wasted_size;
 178                                         c->dirty_size += c->nextblock->free_size + c->nextblock->wasted_size;
 179                                         c->free_size -= c->nextblock->free_size;
 180                                         c->wasted_size -= c->nextblock->wasted_size;
 181                                         c->nextblock->free_size = c->nextblock->wasted_size = 0;
 182                                         if (VERYDIRTY(c, c->nextblock->dirty_size)) {
 183                                                 list_add(&c->nextblock->list, &c->very_dirty_list);
 184                                         } else {
 185                                                 list_add(&c->nextblock->list, &c->dirty_list);
 186                                         }
 187                                 }
 188                                 c->nextblock = jeb;
 189                         } else {
 190                                 jeb->dirty_size += jeb->free_size + jeb->wasted_size;
 191                                 c->dirty_size += jeb->free_size + jeb->wasted_size;
 192                                 c->free_size -= jeb->free_size;
 193                                 c->wasted_size -= jeb->wasted_size;
 194                                 jeb->free_size = jeb->wasted_size = 0;
 195                                 if (VERYDIRTY(c, jeb->dirty_size)) {
 196                                         list_add(&jeb->list, &c->very_dirty_list);
 197                                 } else {
 198                                         list_add(&jeb->list, &c->dirty_list);
 199                                 }
 200                         }
 201                         break;
 202
 203                 case BLK_STATE_ALLDIRTY:
 204                         /* Nothing valid - not even a clean marker. Needs erasing. */
 205                         /* For now we just put it on the erasing list. We'll start the erases later */
 206                         D1(printk(KERN_NOTICE "JFFS2: Erase block at 0x%08x is not formatted. It will be erased\n", jeb->offset));
 207                         list_add(&jeb->list, &c->erase_pending_list);
 208                         c->nr_erasing_blocks++;
 209                         break;
 210
 211                 case BLK_STATE_BADBLOCK:
 212                         D1(printk(KERN_NOTICE "JFFS2: Block at 0x%08x is bad\n", jeb->offset));
 213                         list_add(&jeb->list, &c->bad_list);
 214                         c->bad_size += c->sector_size;
 215                         c->free_size -= c->sector_size;
 216                         bad_blocks++;
 217                         break;
 218                 default:
 219                         printk(KERN_WARNING "jffs2_scan_medium(): unknown block state\n");
 220                         BUG();
 221                 }
 222         }
 223
 224         /* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
 225         if (c->nextblock && (c->nextblock->dirty_size)) {
 226                 c->nextblock->wasted_size += c->nextblock->dirty_size;
 227                 c->wasted_size += c->nextblock->dirty_size;
 228                 c->dirty_size -= c->nextblock->dirty_size;
 229                 c->nextblock->dirty_size = 0;
 230         }
 231 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 232         if (!jffs2_can_mark_obsolete(c) && c->nextblock && (c->nextblock->free_size & (c->wbuf_pagesize-1))) {
 233                 /* If we're going to start writing into a block which already
 234                    contains data, and the end of the data isn't page-aligned,
 235                    skip a little and align it. */
 236
 237                 uint32_t skip = c->nextblock->free_size & (c->wbuf_pagesize-1);
 238
 239                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): Skipping %d bytes in nextblock to ensure page alignment\n",
 240                           skip));
 241                 c->nextblock->wasted_size += skip;
 242                 c->wasted_size += skip;
 243
 244                 c->nextblock->free_size -= skip;
 245                 c->free_size -= skip;
 246         }
 247 #endif
 248         if (c->nr_erasing_blocks) {
 249                 if ( !c->used_size && ((c->nr_free_blocks+empty_blocks+bad_blocks)!= c->nr_blocks || bad_blocks == c->nr_blocks) ) {
 250                         printk(KERN_NOTICE "Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
 251                         printk(KERN_NOTICE "empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",empty_blocks,bad_blocks,c->nr_blocks);
 252                         ret = -EIO;
 253                         goto out;
 254                 }
 255                 jffs2_erase_pending_trigger(c);
 256         }
 257         ret = 0;
 258  out:
 259         if (buf_size)
 260                 kfree(flashbuf);
 261 #ifndef __ECOS
 262         else
 263                 c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
 264 #endif
 265         return ret;
 266 }
 267
 268 static int jffs2_fill_scan_buf (struct jffs2_sb_info *c, unsigned char *buf,
 269                                 uint32_t ofs, uint32_t len)
 270 {
 271         int ret;
 272         size_t retlen;
 273
 274         ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
 275         if (ret) {
 276                 D1(printk(KERN_WARNING "mtd->read(0x%x bytes from 0x%x) returned %d\n", len, ofs, ret));
 277                 return ret;
 278         }
 279         if (retlen < len) {
 280                 D1(printk(KERN_WARNING "Read at 0x%x gave only 0x%zx bytes\n", ofs, retlen));
 281                 return -EIO;
 282         }
 283         D2(printk(KERN_DEBUG "Read 0x%x bytes from 0x%08x into buf\n", len, ofs));
 284         D2(printk(KERN_DEBUG "000: %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x\n",
 285                   buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], buf[6], buf[7], buf[8], buf[9], buf[10], buf[11], buf[12], buf[13], buf[14], buf[15]));
 286         return 0;
 287 }
 288
 289 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 290                                   unsigned char *buf, uint32_t buf_size) {
 291         struct jffs2_unknown_node *node;
 292         struct jffs2_unknown_node crcnode;
 293         uint32_t ofs, prevofs;
 294         uint32_t hdr_crc, buf_ofs, buf_len;
 295         int err;
 296         int noise = 0;
 297 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 298         int cleanmarkerfound = 0;
 299 #endif
 300
 301         ofs = jeb->offset;
 302         prevofs = jeb->offset - 1;
 303
 304         D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs));
 305
 306 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 307         if (jffs2_cleanmarker_oob(c)) {
 308                 int ret = jffs2_check_nand_cleanmarker(c, jeb);
 309                 D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n",ret));
 310                 /* Even if it's not found, we still scan to see
 311                    if the block is empty. We use this information
 312                    to decide whether to erase it or not. */
 313                 switch (ret) {
 314                 case 0:         cleanmarkerfound = 1; break;
 315                 case 1:         break;
 316                 case 2:         return BLK_STATE_BADBLOCK;
 317                 case 3:         return BLK_STATE_ALLDIRTY; /* Block has failed to erase min. once */
 318                 default:        return ret;
 319                 }
 320         }
 321 #endif
 322         buf_ofs = jeb->offset;
 323
 324         if (!buf_size) {
 325                 buf_len = c->sector_size;
 326         } else {
 327                 buf_len = EMPTY_SCAN_SIZE(c->sector_size);
 328                 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
 329                 if (err)
 330                         return err;
 331         }
 332
 333         /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
 334         ofs = 0;
 335
 336         /* Scan only 4KiB of 0xFF before declaring it's empty */
 337         while(ofs < EMPTY_SCAN_SIZE(c->sector_size) && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
 338                 ofs += 4;
 339
 340         if (ofs == EMPTY_SCAN_SIZE(c->sector_size)) {
 341 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 342                 if (jffs2_cleanmarker_oob(c)) {
 343                         /* scan oob, take care of cleanmarker */
 344                         int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
 345                         D2(printk(KERN_NOTICE "jffs2_check_oob_empty returned %d\n",ret));
 346                         switch (ret) {
 347                         case 0:         return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
 348                         case 1:         return BLK_STATE_ALLDIRTY;
 349                         default:        return ret;
 350                         }
 351                 }
 352 #endif
 353                 D1(printk(KERN_DEBUG "Block at 0x%08x is empty (erased)\n", jeb->offset));
 354                 if (c->cleanmarker_size == 0)
 355                         return BLK_STATE_CLEANMARKER;   /* don't bother with re-erase */
 356                 else
 357                         return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
 358         }
 359         if (ofs) {
 360                 D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset,
 361                           jeb->offset + ofs));
 362                 DIRTY_SPACE(ofs);
 363         }
 364
 365         /* Now ofs is a complete physical flash offset as it always was... */
 366         ofs += jeb->offset;
 367
 368         noise = 10;
 369
 370 scan_more:
 371         while(ofs < jeb->offset + c->sector_size) {
 372
 373                 D1(ACCT_PARANOIA_CHECK(jeb));
 374
 375                 cond_resched();
 376
 377                 if (ofs & 3) {
 378                         printk(KERN_WARNING "Eep. ofs 0x%08x not word-aligned!\n", ofs);
 379                         ofs = PAD(ofs);
 380                         continue;
 381                 }
 382                 if (ofs == prevofs) {
 383                         printk(KERN_WARNING "ofs 0x%08x has already been seen. Skipping\n", ofs);
 384                         DIRTY_SPACE(4);
 385                         ofs += 4;
 386                         continue;
 387                 }
 388                 prevofs = ofs;
 389
 390                 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
 391                         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),
 392                                   jeb->offset, c->sector_size, ofs, sizeof(*node)));
 393                         DIRTY_SPACE((jeb->offset + c->sector_size)-ofs);
 394                         break;
 395                 }
 396
 397                 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
 398                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 399                         D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
 400                                   sizeof(struct jffs2_unknown_node), buf_len, ofs));
 401                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 402                         if (err)
 403                                 return err;
 404                         buf_ofs = ofs;
 405                 }
 406
 407                 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
 408
 409                 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
 410                         uint32_t inbuf_ofs;
 411                         uint32_t empty_start;
 412
 413                         empty_start = ofs;
 414                         ofs += 4;
 415
 416                         D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs));
 417                 more_empty:
 418                         inbuf_ofs = ofs - buf_ofs;
 419                         while (inbuf_ofs < buf_len) {
 420                                 if (*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff) {
 421                                         printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n",
 422                                                empty_start, ofs);
 423                                         DIRTY_SPACE(ofs-empty_start);
 424                                         goto scan_more;
 425                                 }
 426
 427                                 inbuf_ofs+=4;
 428                                 ofs += 4;
 429                         }
 430                         /* Ran off end. */
 431                         D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs));
 432
 433                         /* If we're only checking the beginning of a block with a cleanmarker,
 434                            bail now */
 435                         if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&
 436                             c->cleanmarker_size && !jeb->dirty_size && !jeb->first_node->next_phys) {
 437                                 D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE(c->sector_size)));
 438                                 return BLK_STATE_CLEANMARKER;
 439                         }
 440
 441                         /* See how much more there is to read in this eraseblock... */
 442                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 443                         if (!buf_len) {
 444                                 /* No more to read. Break out of main loop without marking
 445                                    this range of empty space as dirty (because it's not) */
 446                                 D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block. Treating as free_space\n",
 447                                           empty_start));
 448                                 break;
 449                         }
 450                         D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs));
 451                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 452                         if (err)
 453                                 return err;
 454                         buf_ofs = ofs;
 455                         goto more_empty;
 456                 }
 457
 458                 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
 459                         printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n", ofs);
 460                         DIRTY_SPACE(4);
 461                         ofs += 4;
 462                         continue;
 463                 }
 464                 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
 465                         D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs));
 466                         DIRTY_SPACE(4);
 467                         ofs += 4;
 468                         continue;
 469                 }
 470                 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
 471                         printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08x\n", ofs);
 472                         printk(KERN_WARNING "You cannot use older JFFS2 filesystems with newer kernels\n");
 473                         DIRTY_SPACE(4);
 474                         ofs += 4;
 475                         continue;
 476                 }
 477                 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
 478                         /* OK. We're out of possibilities. Whinge and move on */
 479                         noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n",
 480                                      JFFS2_MAGIC_BITMASK, ofs,
 481                                      je16_to_cpu(node->magic));
 482                         DIRTY_SPACE(4);
 483                         ofs += 4;
 484                         continue;
 485                 }
 486                 /* We seem to have a node of sorts. Check the CRC */
 487                 crcnode.magic = node->magic;
 488                 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
 489                 crcnode.totlen = node->totlen;
 490                 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
 491
 492                 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
 493                         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",
 494                                      ofs, je16_to_cpu(node->magic),
 495                                      je16_to_cpu(node->nodetype),
 496                                      je32_to_cpu(node->totlen),
 497                                      je32_to_cpu(node->hdr_crc),
 498                                      hdr_crc);
 499                         DIRTY_SPACE(4);
 500                         ofs += 4;
 501                         continue;
 502                 }
 503
 504                 if (ofs + je32_to_cpu(node->totlen) >
 505                     jeb->offset + c->sector_size) {
 506                         /* Eep. Node goes over the end of the erase block. */
 507                         printk(KERN_WARNING "Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
 508                                ofs, je32_to_cpu(node->totlen));
 509                         printk(KERN_WARNING "Perhaps the file system was created with the wrong erase size?\n");
 510                         DIRTY_SPACE(4);
 511                         ofs += 4;
 512                         continue;
 513                 }
 514
 515                 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
 516                         /* Wheee. This is an obsoleted node */
 517                         D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs));
 518                         DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 519                         ofs += PAD(je32_to_cpu(node->totlen));
 520                         continue;
 521                 }
 522
 523                 switch(je16_to_cpu(node->nodetype)) {
 524                 case JFFS2_NODETYPE_INODE:
 525                         if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
 526                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 527                                 D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
 528                                           sizeof(struct jffs2_raw_inode), buf_len, ofs));
 529                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 530                                 if (err)
 531                                         return err;
 532                                 buf_ofs = ofs;
 533                                 node = (void *)buf;
 534                         }
 535                         err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs);
 536                         if (err) return err;
 537                         ofs += PAD(je32_to_cpu(node->totlen));
 538                         break;
 539
 540                 case JFFS2_NODETYPE_DIRENT:
 541                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 542                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 543                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
 544                                           je32_to_cpu(node->totlen), buf_len, ofs));
 545                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 546                                 if (err)
 547                                         return err;
 548                                 buf_ofs = ofs;
 549                                 node = (void *)buf;
 550                         }
 551                         err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs);
 552                         if (err) return err;
 553                         ofs += PAD(je32_to_cpu(node->totlen));
 554                         break;
 555
 556                 case JFFS2_NODETYPE_CLEANMARKER:
 557                         D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs));
 558                         if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
 559                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n",
 560                                        ofs, je32_to_cpu(node->totlen), c->cleanmarker_size);
 561                                 DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
 562                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 563                         } else if (jeb->first_node) {
 564                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n", ofs, jeb->offset);
 565                                 DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
 566                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 567                         } else {
 568                                 struct jffs2_raw_node_ref *marker_ref = jffs2_alloc_raw_node_ref();
 569                                 if (!marker_ref) {
 570                                         printk(KERN_NOTICE "Failed to allocate node ref for clean marker\n");
 571                                         return -ENOMEM;
 572                                 }
 573                                 marker_ref->next_in_ino = NULL;
 574                                 marker_ref->next_phys = NULL;
 575                                 marker_ref->flash_offset = ofs | REF_NORMAL;
 576                                 marker_ref->__totlen = c->cleanmarker_size;
 577                                 jeb->first_node = jeb->last_node = marker_ref;
 578
 579                                 USED_SPACE(PAD(c->cleanmarker_size));
 580                                 ofs += PAD(c->cleanmarker_size);
 581                         }
 582                         break;
 583
 584                 case JFFS2_NODETYPE_PADDING:
 585                         DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 586                         ofs += PAD(je32_to_cpu(node->totlen));
 587                         break;
 588
 589                 default:
 590                         switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
 591                         case JFFS2_FEATURE_ROCOMPAT:
 592                                 printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 593                                 c->flags |= JFFS2_SB_FLAG_RO;
 594                                 if (!(jffs2_is_readonly(c)))
 595                                         return -EROFS;
 596                                 DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 597                                 ofs += PAD(je32_to_cpu(node->totlen));
 598                                 break;
 599
 600                         case JFFS2_FEATURE_INCOMPAT:
 601                                 printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 602                                 return -EINVAL;
 603
 604                         case JFFS2_FEATURE_RWCOMPAT_DELETE:
 605                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 606                                 DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 607                                 ofs += PAD(je32_to_cpu(node->totlen));
 608                                 break;
 609
 610                         case JFFS2_FEATURE_RWCOMPAT_COPY:
 611                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 612                                 USED_SPACE(PAD(je32_to_cpu(node->totlen)));
 613                                 ofs += PAD(je32_to_cpu(node->totlen));
 614                                 break;
 615                         }
 616                 }
 617         }
 618
 619
 620         D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x\n", jeb->offset,
 621                   jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size));
 622
 623         /* mark_node_obsolete can add to wasted !! */
 624         if (jeb->wasted_size) {
 625                 jeb->dirty_size += jeb->wasted_size;
 626                 c->dirty_size += jeb->wasted_size;
 627                 c->wasted_size -= jeb->wasted_size;
 628                 jeb->wasted_size = 0;
 629         }
 630
 631         if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size
 632                 && (!jeb->first_node || !jeb->first_node->next_phys) )
 633                 return BLK_STATE_CLEANMARKER;
 634
 635         /* move blocks with max 4 byte dirty space to cleanlist */
 636         else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
 637                 c->dirty_size -= jeb->dirty_size;
 638                 c->wasted_size += jeb->dirty_size;
 639                 jeb->wasted_size += jeb->dirty_size;
 640                 jeb->dirty_size = 0;
 641                 return BLK_STATE_CLEAN;
 642         } else if (jeb->used_size || jeb->unchecked_size)
 643                 return BLK_STATE_PARTDIRTY;
 644         else
 645                 return BLK_STATE_ALLDIRTY;
 646 }
 647
 648 static struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
 649 {
 650         struct jffs2_inode_cache *ic;
 651
 652         ic = jffs2_get_ino_cache(c, ino);
 653         if (ic)
 654                 return ic;
 655
 656         if (ino > c->highest_ino)
 657                 c->highest_ino = ino;
 658
 659         ic = jffs2_alloc_inode_cache();
 660         if (!ic) {
 661                 printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n");
 662                 return NULL;
 663         }
 664         memset(ic, 0, sizeof(*ic));
 665
 666         ic->ino = ino;
 667         ic->nodes = (void *)ic;
 668         jffs2_add_ino_cache(c, ic);
 669         if (ino == 1)
 670                 ic->nlink = 1;
 671         return ic;
 672 }
 673
 674 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 675                                  struct jffs2_raw_inode *ri, uint32_t ofs)
 676 {
 677         struct jffs2_raw_node_ref *raw;
 678         struct jffs2_inode_cache *ic;
 679         uint32_t ino = je32_to_cpu(ri->ino);
 680
 681         D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs));
 682
 683         /* We do very little here now. Just check the ino# to which we should attribute
 684            this node; we can do all the CRC checking etc. later. There's a tradeoff here --
 685            we used to scan the flash once only, reading everything we want from it into
 686            memory, then building all our in-core data structures and freeing the extra
 687            information. Now we allow the first part of the mount to complete a lot quicker,
 688            but we have to go _back_ to the flash in order to finish the CRC checking, etc.
 689            Which means that the _full_ amount of time to get to proper write mode with GC
 690            operational may actually be _longer_ than before. Sucks to be me. */
 691
 692         raw = jffs2_alloc_raw_node_ref();
 693         if (!raw) {
 694                 printk(KERN_NOTICE "jffs2_scan_inode_node(): allocation of node reference failed\n");
 695                 return -ENOMEM;
 696         }
 697
 698         ic = jffs2_get_ino_cache(c, ino);
 699         if (!ic) {
 700                 /* Inocache get failed. Either we read a bogus ino# or it's just genuinely the
 701                    first node we found for this inode. Do a CRC check to protect against the former
 702                    case */
 703                 uint32_t crc = crc32(0, ri, sizeof(*ri)-8);
 704
 705                 if (crc != je32_to_cpu(ri->node_crc)) {
 706                         printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 707                                ofs, je32_to_cpu(ri->node_crc), crc);
 708                         /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
 709                         DIRTY_SPACE(PAD(je32_to_cpu(ri->totlen)));
 710                         jffs2_free_raw_node_ref(raw);
 711                         return 0;
 712                 }
 713                 ic = jffs2_scan_make_ino_cache(c, ino);
 714                 if (!ic) {
 715                         jffs2_free_raw_node_ref(raw);
 716                         return -ENOMEM;
 717                 }
 718         }
 719
 720         /* Wheee. It worked */
 721
 722         raw->flash_offset = ofs | REF_UNCHECKED;
 723         raw->__totlen = PAD(je32_to_cpu(ri->totlen));
 724         raw->next_phys = NULL;
 725         raw->next_in_ino = ic->nodes;
 726
 727         ic->nodes = raw;
 728         if (!jeb->first_node)
 729                 jeb->first_node = raw;
 730         if (jeb->last_node)
 731                 jeb->last_node->next_phys = raw;
 732         jeb->last_node = raw;
 733
 734         D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
 735                   je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
 736                   je32_to_cpu(ri->offset),
 737                   je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize)));
 738
 739         pseudo_random += je32_to_cpu(ri->version);
 740
 741         UNCHECKED_SPACE(PAD(je32_to_cpu(ri->totlen)));
 742         return 0;
 743 }
 744
 745 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 746                                   struct jffs2_raw_dirent *rd, uint32_t ofs)
 747 {
 748         struct jffs2_raw_node_ref *raw;
 749         struct jffs2_full_dirent *fd;
 750         struct jffs2_inode_cache *ic;
 751         uint32_t crc;
 752
 753         D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs));
 754
 755         /* We don't get here unless the node is still valid, so we don't have to
 756            mask in the ACCURATE bit any more. */
 757         crc = crc32(0, rd, sizeof(*rd)-8);
 758
 759         if (crc != je32_to_cpu(rd->node_crc)) {
 760                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 761                        ofs, je32_to_cpu(rd->node_crc), crc);
 762                 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
 763                 DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
 764                 return 0;
 765         }
 766
 767         pseudo_random += je32_to_cpu(rd->version);
 768
 769         fd = jffs2_alloc_full_dirent(rd->nsize+1);
 770         if (!fd) {
 771                 return -ENOMEM;
 772         }
 773         memcpy(&fd->name, rd->name, rd->nsize);
 774         fd->name[rd->nsize] = 0;
 775
 776         crc = crc32(0, fd->name, rd->nsize);
 777         if (crc != je32_to_cpu(rd->name_crc)) {
 778                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 779                        ofs, je32_to_cpu(rd->name_crc), crc);
 780                 D1(printk(KERN_NOTICE "Name for which CRC failed is (now) '%s', ino #%d\n", fd->name, je32_to_cpu(rd->ino)));
 781                 jffs2_free_full_dirent(fd);
 782                 /* FIXME: Why do we believe totlen? */
 783                 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
 784                 DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
 785                 return 0;
 786         }
 787         raw = jffs2_alloc_raw_node_ref();
 788         if (!raw) {
 789                 jffs2_free_full_dirent(fd);
 790                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): allocation of node reference failed\n");
 791                 return -ENOMEM;
 792         }
 793         ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
 794         if (!ic) {
 795                 jffs2_free_full_dirent(fd);
 796                 jffs2_free_raw_node_ref(raw);
 797                 return -ENOMEM;
 798         }
 799
 800         raw->__totlen = PAD(je32_to_cpu(rd->totlen));
 801         raw->flash_offset = ofs | REF_PRISTINE;
 802         raw->next_phys = NULL;
 803         raw->next_in_ino = ic->nodes;
 804         ic->nodes = raw;
 805         if (!jeb->first_node)
 806                 jeb->first_node = raw;
 807         if (jeb->last_node)
 808                 jeb->last_node->next_phys = raw;
 809         jeb->last_node = raw;
 810
 811         fd->raw = raw;
 812         fd->next = NULL;
 813         fd->version = je32_to_cpu(rd->version);
 814         fd->ino = je32_to_cpu(rd->ino);
 815         fd->nhash = full_name_hash(fd->name, rd->nsize);
 816         fd->type = rd->type;
 817         USED_SPACE(PAD(je32_to_cpu(rd->totlen)));
 818         jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
 819
 820         return 0;
 821 }
 822
 823 static int count_list(struct list_head *l)
 824 {
 825         uint32_t count = 0;
 826         struct list_head *tmp;
 827
 828         list_for_each(tmp, l) {
 829                 count++;
 830         }
 831         return count;
 832 }
 833
 834 /* Note: This breaks if list_empty(head). I don't care. You
 835    might, if you copy this code and use it elsewhere :) */
 836 static void rotate_list(struct list_head *head, uint32_t count)
 837 {
 838         struct list_head *n = head->next;
 839
 840         list_del(head);
 841         while(count--) {
 842                 n = n->next;
 843         }
 844         list_add(head, n);
 845 }
 846
 847 void jffs2_rotate_lists(struct jffs2_sb_info *c)
 848 {
 849         uint32_t x;
 850         uint32_t rotateby;
 851
 852         x = count_list(&c->clean_list);
 853         if (x) {
 854                 rotateby = pseudo_random % x;
 855                 D1(printk(KERN_DEBUG "Rotating clean_list by %d\n", rotateby));
 856
 857                 rotate_list((&c->clean_list), rotateby);
 858
 859                 D1(printk(KERN_DEBUG "Erase block at front of clean_list is at %08x\n",
 860                           list_entry(c->clean_list.next, struct jffs2_eraseblock, list)->offset));
 861         } else {
 862                 D1(printk(KERN_DEBUG "Not rotating empty clean_list\n"));
 863         }
 864
 865         x = count_list(&c->very_dirty_list);
 866         if (x) {
 867                 rotateby = pseudo_random % x;
 868                 D1(printk(KERN_DEBUG "Rotating very_dirty_list by %d\n", rotateby));
 869
 870                 rotate_list((&c->very_dirty_list), rotateby);
 871
 872                 D1(printk(KERN_DEBUG "Erase block at front of very_dirty_list is at %08x\n",
 873                           list_entry(c->very_dirty_list.next, struct jffs2_eraseblock, list)->offset));
 874         } else {
 875                 D1(printk(KERN_DEBUG "Not rotating empty very_dirty_list\n"));
 876         }
 877
 878         x = count_list(&c->dirty_list);
 879         if (x) {
 880                 rotateby = pseudo_random % x;
 881                 D1(printk(KERN_DEBUG "Rotating dirty_list by %d\n", rotateby));
 882
 883                 rotate_list((&c->dirty_list), rotateby);
 884
 885                 D1(printk(KERN_DEBUG "Erase block at front of dirty_list is at %08x\n",
 886                           list_entry(c->dirty_list.next, struct jffs2_eraseblock, list)->offset));
 887         } else {
 888                 D1(printk(KERN_DEBUG "Not rotating empty dirty_list\n"));
 889         }
 890
 891         x = count_list(&c->erasable_list);
 892         if (x) {
 893                 rotateby = pseudo_random % x;
 894                 D1(printk(KERN_DEBUG "Rotating erasable_list by %d\n", rotateby));
 895
 896                 rotate_list((&c->erasable_list), rotateby);
 897
 898                 D1(printk(KERN_DEBUG "Erase block at front of erasable_list is at %08x\n",
 899                           list_entry(c->erasable_list.next, struct jffs2_eraseblock, list)->offset));
 900         } else {
 901                 D1(printk(KERN_DEBUG "Not rotating empty erasable_list\n"));
 902         }
 903
 904         if (c->nr_erasing_blocks) {
 905                 rotateby = pseudo_random % c->nr_erasing_blocks;
 906                 D1(printk(KERN_DEBUG "Rotating erase_pending_list by %d\n", rotateby));
 907
 908                 rotate_list((&c->erase_pending_list), rotateby);
 909
 910                 D1(printk(KERN_DEBUG "Erase block at front of erase_pending_list is at %08x\n",
 911                           list_entry(c->erase_pending_list.next, struct jffs2_eraseblock, list)->offset));
 912         } else {
 913                 D1(printk(KERN_DEBUG "Not rotating empty erase_pending_list\n"));
 914         }
 915
 916         if (c->nr_free_blocks) {
 917                 rotateby = pseudo_random % c->nr_free_blocks;
 918                 D1(printk(KERN_DEBUG "Rotating free_list by %d\n", rotateby));
 919
 920                 rotate_list((&c->free_list), rotateby);
 921
 922                 D1(printk(KERN_DEBUG "Erase block at front of free_list is at %08x\n",
 923                           list_entry(c->free_list.next, struct jffs2_eraseblock, list)->offset));
 924         } else {
 925                 D1(printk(KERN_DEBUG "Not rotating empty free_list\n"));
 926         }
 927 }