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 static int file_dirty(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
  69 {
  70         int ret = jffs2_scan_dirty_space(c, jeb, jeb->free_size);
  71         if (ret)
  72                 return ret;
  73         /* Turned wasted size into dirty, since we apparently
  74            think it's recoverable now. */
  75         jeb->dirty_size += jeb->wasted_size;
  76         c->dirty_size += jeb->wasted_size;
  77         c->wasted_size -= jeb->wasted_size;
  78         jeb->wasted_size = 0;
  79         if (VERYDIRTY(c, jeb->dirty_size)) {
  80                 list_add(&jeb->list, &c->very_dirty_list);
  81         } else {
  82                 list_add(&jeb->list, &c->dirty_list);
  83         }
  84         return 0;
  85 }
  86
  87 int jffs2_scan_medium(struct jffs2_sb_info *c)
  88 {
  89         int i, ret;
  90         uint32_t empty_blocks = 0, bad_blocks = 0;
  91         unsigned char *flashbuf = NULL;
  92         uint32_t buf_size = 0;
  93         struct jffs2_summary *s = NULL; /* summary info collected by the scan process */
  94 #ifndef __ECOS
  95         size_t pointlen;
  96
  97         if (c->mtd->point) {
  98                 ret = c->mtd->point (c->mtd, 0, c->mtd->size, &pointlen, &flashbuf);
  99                 if (!ret && pointlen < c->mtd->size) {
 100                         /* Don't muck about if it won't let us point to the whole flash */
 101                         D1(printk(KERN_DEBUG "MTD point returned len too short: 0x%zx\n", pointlen));
 102                         c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
 103                         flashbuf = NULL;
 104                 }
 105                 if (ret)
 106                         D1(printk(KERN_DEBUG "MTD point failed %d\n", ret));
 107         }
 108 #endif
 109         if (!flashbuf) {
 110                 /* For NAND it's quicker to read a whole eraseblock at a time,
 111                    apparently */
 112                 if (jffs2_cleanmarker_oob(c))
 113                         buf_size = c->sector_size;
 114                 else
 115                         buf_size = PAGE_SIZE;
 116
 117                 /* Respect kmalloc limitations */
 118                 if (buf_size > 128*1024)
 119                         buf_size = 128*1024;
 120
 121                 D1(printk(KERN_DEBUG "Allocating readbuf of %d bytes\n", buf_size));
 122                 flashbuf = kmalloc(buf_size, GFP_KERNEL);
 123                 if (!flashbuf)
 124                         return -ENOMEM;
 125         }
 126
 127         if (jffs2_sum_active()) {
 128                 s = kmalloc(sizeof(struct jffs2_summary), GFP_KERNEL);
 129                 if (!s) {
 130                         JFFS2_WARNING("Can't allocate memory for summary\n");
 131                         return -ENOMEM;
 132                 }
 133                 memset(s, 0, sizeof(struct jffs2_summary));
 134         }
 135
 136         for (i=0; i<c->nr_blocks; i++) {
 137                 struct jffs2_eraseblock *jeb = &c->blocks[i];
 138
 139                 /* reset summary info for next eraseblock scan */
 140                 jffs2_sum_reset_collected(s);
 141
 142                 ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset),
 143                                                 buf_size, s);
 144
 145                 if (ret < 0)
 146                         goto out;
 147
 148                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 149
 150                 /* Now decide which list to put it on */
 151                 switch(ret) {
 152                 case BLK_STATE_ALLFF:
 153                         /*
 154                          * Empty block.   Since we can't be sure it
 155                          * was entirely erased, we just queue it for erase
 156                          * again.  It will be marked as such when the erase
 157                          * is complete.  Meanwhile we still count it as empty
 158                          * for later checks.
 159                          */
 160                         empty_blocks++;
 161                         list_add(&jeb->list, &c->erase_pending_list);
 162                         c->nr_erasing_blocks++;
 163                         break;
 164
 165                 case BLK_STATE_CLEANMARKER:
 166                         /* Only a CLEANMARKER node is valid */
 167                         if (!jeb->dirty_size) {
 168                                 /* It's actually free */
 169                                 list_add(&jeb->list, &c->free_list);
 170                                 c->nr_free_blocks++;
 171                         } else {
 172                                 /* Dirt */
 173                                 D1(printk(KERN_DEBUG "Adding all-dirty block at 0x%08x to erase_pending_list\n", jeb->offset));
 174                                 list_add(&jeb->list, &c->erase_pending_list);
 175                                 c->nr_erasing_blocks++;
 176                         }
 177                         break;
 178
 179                 case BLK_STATE_CLEAN:
 180                         /* Full (or almost full) of clean data. Clean list */
 181                         list_add(&jeb->list, &c->clean_list);
 182                         break;
 183
 184                 case BLK_STATE_PARTDIRTY:
 185                         /* Some data, but not full. Dirty list. */
 186                         /* We want to remember the block with most free space
 187                         and stick it in the 'nextblock' position to start writing to it. */
 188                         if (jeb->free_size > min_free(c) &&
 189                                         (!c->nextblock || c->nextblock->free_size < jeb->free_size)) {
 190                                 /* Better candidate for the next writes to go to */
 191                                 if (c->nextblock) {
 192                                         ret = file_dirty(c, c->nextblock);
 193                                         if (ret)
 194                                                 return ret;
 195                                         /* deleting summary information of the old nextblock */
 196                                         jffs2_sum_reset_collected(c->summary);
 197                                 }
 198                                 /* update collected summary information for the current nextblock */
 199                                 jffs2_sum_move_collected(c, s);
 200                                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): new nextblock = 0x%08x\n", jeb->offset));
 201                                 c->nextblock = jeb;
 202                         } else {
 203                                 ret = file_dirty(c, jeb);
 204                                 if (ret)
 205                                         return ret;
 206                         }
 207                         break;
 208
 209                 case BLK_STATE_ALLDIRTY:
 210                         /* Nothing valid - not even a clean marker. Needs erasing. */
 211                         /* For now we just put it on the erasing list. We'll start the erases later */
 212                         D1(printk(KERN_NOTICE "JFFS2: Erase block at 0x%08x is not formatted. It will be erased\n", jeb->offset));
 213                         list_add(&jeb->list, &c->erase_pending_list);
 214                         c->nr_erasing_blocks++;
 215                         break;
 216
 217                 case BLK_STATE_BADBLOCK:
 218                         D1(printk(KERN_NOTICE "JFFS2: Block at 0x%08x is bad\n", jeb->offset));
 219                         list_add(&jeb->list, &c->bad_list);
 220                         c->bad_size += c->sector_size;
 221                         c->free_size -= c->sector_size;
 222                         bad_blocks++;
 223                         break;
 224                 default:
 225                         printk(KERN_WARNING "jffs2_scan_medium(): unknown block state\n");
 226                         BUG();
 227                 }
 228         }
 229
 230         /* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
 231         if (c->nextblock && (c->nextblock->dirty_size)) {
 232                 c->nextblock->wasted_size += c->nextblock->dirty_size;
 233                 c->wasted_size += c->nextblock->dirty_size;
 234                 c->dirty_size -= c->nextblock->dirty_size;
 235                 c->nextblock->dirty_size = 0;
 236         }
 237 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 238         if (!jffs2_can_mark_obsolete(c) && c->wbuf_pagesize && c->nextblock && (c->nextblock->free_size % c->wbuf_pagesize)) {
 239                 /* If we're going to start writing into a block which already
 240                    contains data, and the end of the data isn't page-aligned,
 241                    skip a little and align it. */
 242
 243                 uint32_t skip = c->nextblock->free_size % c->wbuf_pagesize;
 244
 245                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): Skipping %d bytes in nextblock to ensure page alignment\n",
 246                           skip));
 247                 jffs2_prealloc_raw_node_refs(c, c->nextblock, 1);
 248                 jffs2_scan_dirty_space(c, c->nextblock, skip);
 249         }
 250 #endif
 251         if (c->nr_erasing_blocks) {
 252                 if ( !c->used_size && ((c->nr_free_blocks+empty_blocks+bad_blocks)!= c->nr_blocks || bad_blocks == c->nr_blocks) ) {
 253                         printk(KERN_NOTICE "Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
 254                         printk(KERN_NOTICE "empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",empty_blocks,bad_blocks,c->nr_blocks);
 255                         ret = -EIO;
 256                         goto out;
 257                 }
 258                 jffs2_erase_pending_trigger(c);
 259         }
 260         ret = 0;
 261  out:
 262         if (buf_size)
 263                 kfree(flashbuf);
 264 #ifndef __ECOS
 265         else
 266                 c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
 267 #endif
 268         if (s)
 269                 kfree(s);
 270
 271         return ret;
 272 }
 273
 274 int jffs2_fill_scan_buf (struct jffs2_sb_info *c, void *buf,
 275                                 uint32_t ofs, uint32_t len)
 276 {
 277         int ret;
 278         size_t retlen;
 279
 280         ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
 281         if (ret) {
 282                 D1(printk(KERN_WARNING "mtd->read(0x%x bytes from 0x%x) returned %d\n", len, ofs, ret));
 283                 return ret;
 284         }
 285         if (retlen < len) {
 286                 D1(printk(KERN_WARNING "Read at 0x%x gave only 0x%zx bytes\n", ofs, retlen));
 287                 return -EIO;
 288         }
 289         return 0;
 290 }
 291
 292 int jffs2_scan_classify_jeb(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
 293 {
 294         if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size
 295             && (!jeb->first_node || !ref_next(jeb->first_node)) )
 296                 return BLK_STATE_CLEANMARKER;
 297
 298         /* move blocks with max 4 byte dirty space to cleanlist */
 299         else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
 300                 c->dirty_size -= jeb->dirty_size;
 301                 c->wasted_size += jeb->dirty_size;
 302                 jeb->wasted_size += jeb->dirty_size;
 303                 jeb->dirty_size = 0;
 304                 return BLK_STATE_CLEAN;
 305         } else if (jeb->used_size || jeb->unchecked_size)
 306                 return BLK_STATE_PARTDIRTY;
 307         else
 308                 return BLK_STATE_ALLDIRTY;
 309 }
 310
 311 #ifdef CONFIG_JFFS2_FS_XATTR
 312 static int jffs2_scan_xattr_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 313                                  struct jffs2_raw_xattr *rx, uint32_t ofs,
 314                                  struct jffs2_summary *s)
 315 {
 316         struct jffs2_xattr_datum *xd;
 317         uint32_t totlen, crc;
 318         int err;
 319
 320         crc = crc32(0, rx, sizeof(struct jffs2_raw_xattr) - 4);
 321         if (crc != je32_to_cpu(rx->node_crc)) {
 322                 if (je32_to_cpu(rx->node_crc) != 0xffffffff)
 323                         JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
 324                                       ofs, je32_to_cpu(rx->node_crc), crc);
 325                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
 326                         return err;
 327                 return 0;
 328         }
 329
 330         totlen = PAD(sizeof(*rx) + rx->name_len + 1 + je16_to_cpu(rx->value_len));
 331         if (totlen != je32_to_cpu(rx->totlen)) {
 332                 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%u\n",
 333                               ofs, je32_to_cpu(rx->totlen), totlen);
 334                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
 335                         return err;
 336                 return 0;
 337         }
 338
 339         xd = jffs2_setup_xattr_datum(c, je32_to_cpu(rx->xid), je32_to_cpu(rx->version));
 340         if (IS_ERR(xd)) {
 341                 if (PTR_ERR(xd) == -EEXIST) {
 342                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rx->totlen)))))
 343                                 return err;
 344                         return 0;
 345                 }
 346                 return PTR_ERR(xd);
 347         }
 348         xd->xprefix = rx->xprefix;
 349         xd->name_len = rx->name_len;
 350         xd->value_len = je16_to_cpu(rx->value_len);
 351         xd->data_crc = je32_to_cpu(rx->data_crc);
 352
 353         xd->node = jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, NULL);
 354         /* FIXME */ xd->node->next_in_ino = (void *)xd;
 355
 356         if (jffs2_sum_active())
 357                 jffs2_sum_add_xattr_mem(s, rx, ofs - jeb->offset);
 358         dbg_xattr("scaning xdatum at %#08x (xid=%u, version=%u)\n",
 359                   ofs, xd->xid, xd->version);
 360         return 0;
 361 }
 362
 363 static int jffs2_scan_xref_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 364                                 struct jffs2_raw_xref *rr, uint32_t ofs,
 365                                 struct jffs2_summary *s)
 366 {
 367         struct jffs2_xattr_ref *ref;
 368         uint32_t crc;
 369         int err;
 370
 371         crc = crc32(0, rr, sizeof(*rr) - 4);
 372         if (crc != je32_to_cpu(rr->node_crc)) {
 373                 if (je32_to_cpu(rr->node_crc) != 0xffffffff)
 374                         JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
 375                                       ofs, je32_to_cpu(rr->node_crc), crc);
 376                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rr->totlen)))))
 377                         return err;
 378                 return 0;
 379         }
 380
 381         if (PAD(sizeof(struct jffs2_raw_xref)) != je32_to_cpu(rr->totlen)) {
 382                 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%u\n",
 383                               ofs, je32_to_cpu(rr->totlen),
 384                               PAD(sizeof(struct jffs2_raw_xref)));
 385                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rr->totlen))))
 386                         return err;
 387                 return 0;
 388         }
 389
 390         ref = jffs2_alloc_xattr_ref();
 391         if (!ref)
 392                 return -ENOMEM;
 393
 394         /* BEFORE jffs2_build_xattr_subsystem() called,
 395          * ref->xid is used to store 32bit xid, xd is not used
 396          * ref->ino is used to store 32bit inode-number, ic is not used
 397          * Thoes variables are declared as union, thus using those
 398          * are exclusive. In a similar way, ref->next is temporarily
 399          * used to chain all xattr_ref object. It's re-chained to
 400          * jffs2_inode_cache in jffs2_build_xattr_subsystem() correctly.
 401          */
 402         ref->ino = je32_to_cpu(rr->ino);
 403         ref->xid = je32_to_cpu(rr->xid);
 404         ref->next = c->xref_temp;
 405         c->xref_temp = ref;
 406
 407         ref->node = jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(rr->totlen)), NULL);
 408         /* FIXME */ ref->node->next_in_ino = (void *)ref;
 409
 410         if (jffs2_sum_active())
 411                 jffs2_sum_add_xref_mem(s, rr, ofs - jeb->offset);
 412         dbg_xattr("scan xref at %#08x (xid=%u, ino=%u)\n",
 413                   ofs, ref->xid, ref->ino);
 414         return 0;
 415 }
 416 #endif
 417
 418 /* Called with 'buf_size == 0' if buf is in fact a pointer _directly_ into
 419    the flash, XIP-style */
 420 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 421                                   unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) {
 422         struct jffs2_unknown_node *node;
 423         struct jffs2_unknown_node crcnode;
 424         uint32_t ofs, prevofs;
 425         uint32_t hdr_crc, buf_ofs, buf_len;
 426         int err;
 427         int noise = 0;
 428
 429
 430 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 431         int cleanmarkerfound = 0;
 432 #endif
 433
 434         ofs = jeb->offset;
 435         prevofs = jeb->offset - 1;
 436
 437         D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs));
 438
 439 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 440         if (jffs2_cleanmarker_oob(c)) {
 441                 int ret = jffs2_check_nand_cleanmarker(c, jeb);
 442                 D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n",ret));
 443                 /* Even if it's not found, we still scan to see
 444                    if the block is empty. We use this information
 445                    to decide whether to erase it or not. */
 446                 switch (ret) {
 447                 case 0:         cleanmarkerfound = 1; break;
 448                 case 1:         break;
 449                 case 2:         return BLK_STATE_BADBLOCK;
 450                 case 3:         return BLK_STATE_ALLDIRTY; /* Block has failed to erase min. once */
 451                 default:        return ret;
 452                 }
 453         }
 454 #endif
 455
 456         if (jffs2_sum_active()) {
 457                 struct jffs2_sum_marker *sm;
 458                 void *sumptr = NULL;
 459                 uint32_t sumlen;
 460
 461                 if (!buf_size) {
 462                         /* XIP case. Just look, point at the summary if it's there */
 463                         sm = (void *)buf + jeb->offset - sizeof(*sm);
 464                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
 465                                 sumptr = buf + je32_to_cpu(sm->offset);
 466                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
 467                         }
 468                 } else {
 469                         /* If NAND flash, read a whole page of it. Else just the end */
 470                         if (c->wbuf_pagesize)
 471                                 buf_len = c->wbuf_pagesize;
 472                         else
 473                                 buf_len = sizeof(*sm);
 474
 475                         /* Read as much as we want into the _end_ of the preallocated buffer */
 476                         err = jffs2_fill_scan_buf(c, buf + buf_size - buf_len,
 477                                                   jeb->offset + c->sector_size - buf_len,
 478                                                   buf_len);
 479                         if (err)
 480                                 return err;
 481
 482                         sm = (void *)buf + buf_size - sizeof(*sm);
 483                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
 484                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
 485                                 sumptr = buf + buf_size - sumlen;
 486
 487                                 /* Now, make sure the summary itself is available */
 488                                 if (sumlen > buf_size) {
 489                                         /* Need to kmalloc for this. */
 490                                         sumptr = kmalloc(sumlen, GFP_KERNEL);
 491                                         if (!sumptr)
 492                                                 return -ENOMEM;
 493                                         memcpy(sumptr + sumlen - buf_len, buf + buf_size - buf_len, buf_len);
 494                                 }
 495                                 if (buf_len < sumlen) {
 496                                         /* Need to read more so that the entire summary node is present */
 497                                         err = jffs2_fill_scan_buf(c, sumptr,
 498                                                                   jeb->offset + c->sector_size - sumlen,
 499                                                                   sumlen - buf_len);
 500                                         if (err)
 501                                                 return err;
 502                                 }
 503                         }
 504
 505                 }
 506
 507                 if (sumptr) {
 508                         err = jffs2_sum_scan_sumnode(c, jeb, sumptr, sumlen, &pseudo_random);
 509
 510                         if (buf_size && sumlen > buf_size)
 511                                 kfree(sumptr);
 512                         /* If it returns with a real error, bail.
 513                            If it returns positive, that's a block classification
 514                            (i.e. BLK_STATE_xxx) so return that too.
 515                            If it returns zero, fall through to full scan. */
 516                         if (err)
 517                                 return err;
 518                 }
 519         }
 520
 521         buf_ofs = jeb->offset;
 522
 523         if (!buf_size) {
 524                 /* This is the XIP case -- we're reading _directly_ from the flash chip */
 525                 buf_len = c->sector_size;
 526         } else {
 527                 buf_len = EMPTY_SCAN_SIZE(c->sector_size);
 528                 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
 529                 if (err)
 530                         return err;
 531         }
 532
 533         /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
 534         ofs = 0;
 535
 536         /* Scan only 4KiB of 0xFF before declaring it's empty */
 537         while(ofs < EMPTY_SCAN_SIZE(c->sector_size) && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
 538                 ofs += 4;
 539
 540         if (ofs == EMPTY_SCAN_SIZE(c->sector_size)) {
 541 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 542                 if (jffs2_cleanmarker_oob(c)) {
 543                         /* scan oob, take care of cleanmarker */
 544                         int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
 545                         D2(printk(KERN_NOTICE "jffs2_check_oob_empty returned %d\n",ret));
 546                         switch (ret) {
 547                         case 0:         return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
 548                         case 1:         return BLK_STATE_ALLDIRTY;
 549                         default:        return ret;
 550                         }
 551                 }
 552 #endif
 553                 D1(printk(KERN_DEBUG "Block at 0x%08x is empty (erased)\n", jeb->offset));
 554                 if (c->cleanmarker_size == 0)
 555                         return BLK_STATE_CLEANMARKER;   /* don't bother with re-erase */
 556                 else
 557                         return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
 558         }
 559         if (ofs) {
 560                 D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset,
 561                           jeb->offset + ofs));
 562                 if ((err = jffs2_scan_dirty_space(c, jeb, ofs)))
 563                         return err;
 564         }
 565
 566         /* Now ofs is a complete physical flash offset as it always was... */
 567         ofs += jeb->offset;
 568
 569         noise = 10;
 570
 571         dbg_summary("no summary found in jeb 0x%08x. Apply original scan.\n",jeb->offset);
 572
 573 scan_more:
 574         while(ofs < jeb->offset + c->sector_size) {
 575
 576                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 577
 578                 /* Make sure there are node refs available for use */
 579                 err = jffs2_prealloc_raw_node_refs(c, jeb, 2);
 580                 if (err)
 581                         return err;
 582
 583                 cond_resched();
 584
 585                 if (ofs & 3) {
 586                         printk(KERN_WARNING "Eep. ofs 0x%08x not word-aligned!\n", ofs);
 587                         ofs = PAD(ofs);
 588                         continue;
 589                 }
 590                 if (ofs == prevofs) {
 591                         printk(KERN_WARNING "ofs 0x%08x has already been seen. Skipping\n", ofs);
 592                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 593                                 return err;
 594                         ofs += 4;
 595                         continue;
 596                 }
 597                 prevofs = ofs;
 598
 599                 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
 600                         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),
 601                                   jeb->offset, c->sector_size, ofs, sizeof(*node)));
 602                         if ((err = jffs2_scan_dirty_space(c, jeb, (jeb->offset + c->sector_size)-ofs)))
 603                                 return err;
 604                         break;
 605                 }
 606
 607                 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
 608                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 609                         D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
 610                                   sizeof(struct jffs2_unknown_node), buf_len, ofs));
 611                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 612                         if (err)
 613                                 return err;
 614                         buf_ofs = ofs;
 615                 }
 616
 617                 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
 618
 619                 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
 620                         uint32_t inbuf_ofs;
 621                         uint32_t empty_start;
 622
 623                         empty_start = ofs;
 624                         ofs += 4;
 625
 626                         D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs));
 627                 more_empty:
 628                         inbuf_ofs = ofs - buf_ofs;
 629                         while (inbuf_ofs < buf_len) {
 630                                 if (*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff) {
 631                                         printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n",
 632                                                empty_start, ofs);
 633                                         if ((err = jffs2_scan_dirty_space(c, jeb, ofs-empty_start)))
 634                                                 return err;
 635                                         goto scan_more;
 636                                 }
 637
 638                                 inbuf_ofs+=4;
 639                                 ofs += 4;
 640                         }
 641                         /* Ran off end. */
 642                         D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs));
 643
 644                         /* If we're only checking the beginning of a block with a cleanmarker,
 645                            bail now */
 646                         if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&
 647                             c->cleanmarker_size && !jeb->dirty_size && !ref_next(jeb->first_node)) {
 648                                 D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE(c->sector_size)));
 649                                 return BLK_STATE_CLEANMARKER;
 650                         }
 651
 652                         /* See how much more there is to read in this eraseblock... */
 653                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 654                         if (!buf_len) {
 655                                 /* No more to read. Break out of main loop without marking
 656                                    this range of empty space as dirty (because it's not) */
 657                                 D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block. Treating as free_space\n",
 658                                           empty_start));
 659                                 break;
 660                         }
 661                         D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs));
 662                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 663                         if (err)
 664                                 return err;
 665                         buf_ofs = ofs;
 666                         goto more_empty;
 667                 }
 668
 669                 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
 670                         printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n", ofs);
 671                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 672                                 return err;
 673                         ofs += 4;
 674                         continue;
 675                 }
 676                 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
 677                         D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs));
 678                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 679                                 return err;
 680                         ofs += 4;
 681                         continue;
 682                 }
 683                 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
 684                         printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08x\n", ofs);
 685                         printk(KERN_WARNING "You cannot use older JFFS2 filesystems with newer kernels\n");
 686                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 687                                 return err;
 688                         ofs += 4;
 689                         continue;
 690                 }
 691                 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
 692                         /* OK. We're out of possibilities. Whinge and move on */
 693                         noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n",
 694                                      JFFS2_MAGIC_BITMASK, ofs,
 695                                      je16_to_cpu(node->magic));
 696                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 697                                 return err;
 698                         ofs += 4;
 699                         continue;
 700                 }
 701                 /* We seem to have a node of sorts. Check the CRC */
 702                 crcnode.magic = node->magic;
 703                 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
 704                 crcnode.totlen = node->totlen;
 705                 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
 706
 707                 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
 708                         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",
 709                                      ofs, je16_to_cpu(node->magic),
 710                                      je16_to_cpu(node->nodetype),
 711                                      je32_to_cpu(node->totlen),
 712                                      je32_to_cpu(node->hdr_crc),
 713                                      hdr_crc);
 714                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 715                                 return err;
 716                         ofs += 4;
 717                         continue;
 718                 }
 719
 720                 if (ofs + je32_to_cpu(node->totlen) >
 721                     jeb->offset + c->sector_size) {
 722                         /* Eep. Node goes over the end of the erase block. */
 723                         printk(KERN_WARNING "Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
 724                                ofs, je32_to_cpu(node->totlen));
 725                         printk(KERN_WARNING "Perhaps the file system was created with the wrong erase size?\n");
 726                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 727                                 return err;
 728                         ofs += 4;
 729                         continue;
 730                 }
 731
 732                 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
 733                         /* Wheee. This is an obsoleted node */
 734                         D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs));
 735                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 736                                 return err;
 737                         ofs += PAD(je32_to_cpu(node->totlen));
 738                         continue;
 739                 }
 740
 741                 switch(je16_to_cpu(node->nodetype)) {
 742                 case JFFS2_NODETYPE_INODE:
 743                         if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
 744                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 745                                 D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
 746                                           sizeof(struct jffs2_raw_inode), buf_len, ofs));
 747                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 748                                 if (err)
 749                                         return err;
 750                                 buf_ofs = ofs;
 751                                 node = (void *)buf;
 752                         }
 753                         err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs, s);
 754                         if (err) return err;
 755                         ofs += PAD(je32_to_cpu(node->totlen));
 756                         break;
 757
 758                 case JFFS2_NODETYPE_DIRENT:
 759                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 760                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 761                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
 762                                           je32_to_cpu(node->totlen), buf_len, ofs));
 763                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 764                                 if (err)
 765                                         return err;
 766                                 buf_ofs = ofs;
 767                                 node = (void *)buf;
 768                         }
 769                         err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs, s);
 770                         if (err) return err;
 771                         ofs += PAD(je32_to_cpu(node->totlen));
 772                         break;
 773
 774 #ifdef CONFIG_JFFS2_FS_XATTR
 775                 case JFFS2_NODETYPE_XATTR:
 776                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 777                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 778                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (xattr node)"
 779                                           " left to end of buf. Reading 0x%x at 0x%08x\n",
 780                                           je32_to_cpu(node->totlen), buf_len, ofs));
 781                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 782                                 if (err)
 783                                         return err;
 784                                 buf_ofs = ofs;
 785                                 node = (void *)buf;
 786                         }
 787                         err = jffs2_scan_xattr_node(c, jeb, (void *)node, ofs, s);
 788                         if (err)
 789                                 return err;
 790                         ofs += PAD(je32_to_cpu(node->totlen));
 791                         break;
 792                 case JFFS2_NODETYPE_XREF:
 793                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 794                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 795                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (xref node)"
 796                                           " left to end of buf. Reading 0x%x at 0x%08x\n",
 797                                           je32_to_cpu(node->totlen), buf_len, ofs));
 798                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 799                                 if (err)
 800                                         return err;
 801                                 buf_ofs = ofs;
 802                                 node = (void *)buf;
 803                         }
 804                         err = jffs2_scan_xref_node(c, jeb, (void *)node, ofs, s);
 805                         if (err)
 806                                 return err;
 807                         ofs += PAD(je32_to_cpu(node->totlen));
 808                         break;
 809 #endif  /* CONFIG_JFFS2_FS_XATTR */
 810
 811                 case JFFS2_NODETYPE_CLEANMARKER:
 812                         D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs));
 813                         if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
 814                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n",
 815                                        ofs, je32_to_cpu(node->totlen), c->cleanmarker_size);
 816                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
 817                                         return err;
 818                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 819                         } else if (jeb->first_node) {
 820                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n", ofs, jeb->offset);
 821                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
 822                                         return err;
 823                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 824                         } else {
 825                                 jffs2_link_node_ref(c, jeb, ofs | REF_NORMAL, c->cleanmarker_size, NULL);
 826
 827                                 ofs += PAD(c->cleanmarker_size);
 828                         }
 829                         break;
 830
 831                 case JFFS2_NODETYPE_PADDING:
 832                         if (jffs2_sum_active())
 833                                 jffs2_sum_add_padding_mem(s, je32_to_cpu(node->totlen));
 834                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 835                                 return err;
 836                         ofs += PAD(je32_to_cpu(node->totlen));
 837                         break;
 838
 839                 default:
 840                         switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
 841                         case JFFS2_FEATURE_ROCOMPAT:
 842                                 printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 843                                 c->flags |= JFFS2_SB_FLAG_RO;
 844                                 if (!(jffs2_is_readonly(c)))
 845                                         return -EROFS;
 846                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 847                                         return err;
 848                                 ofs += PAD(je32_to_cpu(node->totlen));
 849                                 break;
 850
 851                         case JFFS2_FEATURE_INCOMPAT:
 852                                 printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 853                                 return -EINVAL;
 854
 855                         case JFFS2_FEATURE_RWCOMPAT_DELETE:
 856                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 857                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 858                                         return err;
 859                                 ofs += PAD(je32_to_cpu(node->totlen));
 860                                 break;
 861
 862                         case JFFS2_FEATURE_RWCOMPAT_COPY: {
 863                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 864
 865                                 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(node->totlen)), NULL);
 866
 867                                 /* We can't summarise nodes we don't grok */
 868                                 jffs2_sum_disable_collecting(s);
 869                                 ofs += PAD(je32_to_cpu(node->totlen));
 870                                 break;
 871                                 }
 872                         }
 873                 }
 874         }
 875
 876         if (jffs2_sum_active()) {
 877                 if (PAD(s->sum_size + JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size) {
 878                         dbg_summary("There is not enough space for "
 879                                 "summary information, disabling for this jeb!\n");
 880                         jffs2_sum_disable_collecting(s);
 881                 }
 882         }
 883
 884         D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x\n", jeb->offset,
 885                   jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size));
 886
 887         /* mark_node_obsolete can add to wasted !! */
 888         if (jeb->wasted_size) {
 889                 jeb->dirty_size += jeb->wasted_size;
 890                 c->dirty_size += jeb->wasted_size;
 891                 c->wasted_size -= jeb->wasted_size;
 892                 jeb->wasted_size = 0;
 893         }
 894
 895         return jffs2_scan_classify_jeb(c, jeb);
 896 }
 897
 898 struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
 899 {
 900         struct jffs2_inode_cache *ic;
 901
 902         ic = jffs2_get_ino_cache(c, ino);
 903         if (ic)
 904                 return ic;
 905
 906         if (ino > c->highest_ino)
 907                 c->highest_ino = ino;
 908
 909         ic = jffs2_alloc_inode_cache();
 910         if (!ic) {
 911                 printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n");
 912                 return NULL;
 913         }
 914         memset(ic, 0, sizeof(*ic));
 915
 916         ic->ino = ino;
 917         ic->nodes = (void *)ic;
 918         jffs2_add_ino_cache(c, ic);
 919         if (ino == 1)
 920                 ic->nlink = 1;
 921         return ic;
 922 }
 923
 924 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 925                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s)
 926 {
 927         struct jffs2_inode_cache *ic;
 928         uint32_t ino = je32_to_cpu(ri->ino);
 929         int err;
 930
 931         D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs));
 932
 933         /* We do very little here now. Just check the ino# to which we should attribute
 934            this node; we can do all the CRC checking etc. later. There's a tradeoff here --
 935            we used to scan the flash once only, reading everything we want from it into
 936            memory, then building all our in-core data structures and freeing the extra
 937            information. Now we allow the first part of the mount to complete a lot quicker,
 938            but we have to go _back_ to the flash in order to finish the CRC checking, etc.
 939            Which means that the _full_ amount of time to get to proper write mode with GC
 940            operational may actually be _longer_ than before. Sucks to be me. */
 941
 942         ic = jffs2_get_ino_cache(c, ino);
 943         if (!ic) {
 944                 /* Inocache get failed. Either we read a bogus ino# or it's just genuinely the
 945                    first node we found for this inode. Do a CRC check to protect against the former
 946                    case */
 947                 uint32_t crc = crc32(0, ri, sizeof(*ri)-8);
 948
 949                 if (crc != je32_to_cpu(ri->node_crc)) {
 950                         printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 951                                ofs, je32_to_cpu(ri->node_crc), crc);
 952                         /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
 953                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(ri->totlen)))))
 954                                 return err;
 955                         return 0;
 956                 }
 957                 ic = jffs2_scan_make_ino_cache(c, ino);
 958                 if (!ic)
 959                         return -ENOMEM;
 960         }
 961
 962         /* Wheee. It worked */
 963         jffs2_link_node_ref(c, jeb, ofs | REF_UNCHECKED, PAD(je32_to_cpu(ri->totlen)), ic);
 964
 965         D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
 966                   je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
 967                   je32_to_cpu(ri->offset),
 968                   je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize)));
 969
 970         pseudo_random += je32_to_cpu(ri->version);
 971
 972         if (jffs2_sum_active()) {
 973                 jffs2_sum_add_inode_mem(s, ri, ofs - jeb->offset);
 974         }
 975
 976         return 0;
 977 }
 978
 979 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 980                                   struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s)
 981 {
 982         struct jffs2_full_dirent *fd;
 983         struct jffs2_inode_cache *ic;
 984         uint32_t crc;
 985         int err;
 986
 987         D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs));
 988
 989         /* We don't get here unless the node is still valid, so we don't have to
 990            mask in the ACCURATE bit any more. */
 991         crc = crc32(0, rd, sizeof(*rd)-8);
 992
 993         if (crc != je32_to_cpu(rd->node_crc)) {
 994                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 995                        ofs, je32_to_cpu(rd->node_crc), crc);
 996                 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
 997                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
 998                         return err;
 999                 return 0;
1000         }
1001
1002         pseudo_random += je32_to_cpu(rd->version);
1003
1004         fd = jffs2_alloc_full_dirent(rd->nsize+1);
1005         if (!fd) {
1006                 return -ENOMEM;
1007         }
1008         memcpy(&fd->name, rd->name, rd->nsize);
1009         fd->name[rd->nsize] = 0;
1010
1011         crc = crc32(0, fd->name, rd->nsize);
1012         if (crc != je32_to_cpu(rd->name_crc)) {
1013                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1014                        ofs, je32_to_cpu(rd->name_crc), crc);
1015                 D1(printk(KERN_NOTICE "Name for which CRC failed is (now) '%s', ino #%d\n", fd->name, je32_to_cpu(rd->ino)));
1016                 jffs2_free_full_dirent(fd);
1017                 /* FIXME: Why do we believe totlen? */
1018                 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
1019                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1020                         return err;
1021                 return 0;
1022         }
1023         ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
1024         if (!ic) {
1025                 jffs2_free_full_dirent(fd);
1026                 return -ENOMEM;
1027         }
1028
1029         fd->raw = jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(rd->totlen)), ic);
1030
1031         fd->next = NULL;
1032         fd->version = je32_to_cpu(rd->version);
1033         fd->ino = je32_to_cpu(rd->ino);
1034         fd->nhash = full_name_hash(fd->name, rd->nsize);
1035         fd->type = rd->type;
1036         jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
1037
1038         if (jffs2_sum_active()) {
1039                 jffs2_sum_add_dirent_mem(s, rd, ofs - jeb->offset);
1040         }
1041
1042         return 0;
1043 }
1044
1045 static int count_list(struct list_head *l)
1046 {
1047         uint32_t count = 0;
1048         struct list_head *tmp;
1049
1050         list_for_each(tmp, l) {
1051                 count++;
1052         }
1053         return count;
1054 }
1055
1056 /* Note: This breaks if list_empty(head). I don't care. You
1057    might, if you copy this code and use it elsewhere :) */
1058 static void rotate_list(struct list_head *head, uint32_t count)
1059 {
1060         struct list_head *n = head->next;
1061
1062         list_del(head);
1063         while(count--) {
1064                 n = n->next;
1065         }
1066         list_add(head, n);
1067 }
1068
1069 void jffs2_rotate_lists(struct jffs2_sb_info *c)
1070 {
1071         uint32_t x;
1072         uint32_t rotateby;
1073
1074         x = count_list(&c->clean_list);
1075         if (x) {
1076                 rotateby = pseudo_random % x;
1077                 rotate_list((&c->clean_list), rotateby);
1078         }
1079
1080         x = count_list(&c->very_dirty_list);
1081         if (x) {
1082                 rotateby = pseudo_random % x;
1083                 rotate_list((&c->very_dirty_list), rotateby);
1084         }
1085
1086         x = count_list(&c->dirty_list);
1087         if (x) {
1088                 rotateby = pseudo_random % x;
1089                 rotate_list((&c->dirty_list), rotateby);
1090         }
1091
1092         x = count_list(&c->erasable_list);
1093         if (x) {
1094                 rotateby = pseudo_random % x;
1095                 rotate_list((&c->erasable_list), rotateby);
1096         }
1097
1098         if (c->nr_erasing_blocks) {
1099                 rotateby = pseudo_random % c->nr_erasing_blocks;
1100                 rotate_list((&c->erase_pending_list), rotateby);
1101         }
1102
1103         if (c->nr_free_blocks) {
1104                 rotateby = pseudo_random % c->nr_free_blocks;
1105                 rotate_list((&c->free_list), rotateby);
1106         }
1107 }