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;
  71
  72         if ((ret = jffs2_prealloc_raw_node_refs(c, jeb, 1)))
  73                 return ret;
  74         if ((ret = jffs2_scan_dirty_space(c, jeb, jeb->free_size)))
  75                 return ret;
  76         /* Turned wasted size into dirty, since we apparently
  77            think it's recoverable now. */
  78         jeb->dirty_size += jeb->wasted_size;
  79         c->dirty_size += jeb->wasted_size;
  80         c->wasted_size -= jeb->wasted_size;
  81         jeb->wasted_size = 0;
  82         if (VERYDIRTY(c, jeb->dirty_size)) {
  83                 list_add(&jeb->list, &c->very_dirty_list);
  84         } else {
  85                 list_add(&jeb->list, &c->dirty_list);
  86         }
  87         return 0;
  88 }
  89
  90 int jffs2_scan_medium(struct jffs2_sb_info *c)
  91 {
  92         int i, ret;
  93         uint32_t empty_blocks = 0, bad_blocks = 0;
  94         unsigned char *flashbuf = NULL;
  95         uint32_t buf_size = 0;
  96         struct jffs2_summary *s = NULL; /* summary info collected by the scan process */
  97 #ifndef __ECOS
  98         size_t pointlen;
  99
 100         if (c->mtd->point) {
 101                 ret = c->mtd->point (c->mtd, 0, c->mtd->size, &pointlen, &flashbuf);
 102                 if (!ret && pointlen < c->mtd->size) {
 103                         /* Don't muck about if it won't let us point to the whole flash */
 104                         D1(printk(KERN_DEBUG "MTD point returned len too short: 0x%zx\n", pointlen));
 105                         c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
 106                         flashbuf = NULL;
 107                 }
 108                 if (ret)
 109                         D1(printk(KERN_DEBUG "MTD point failed %d\n", ret));
 110         }
 111 #endif
 112         if (!flashbuf) {
 113                 /* For NAND it's quicker to read a whole eraseblock at a time,
 114                    apparently */
 115                 if (jffs2_cleanmarker_oob(c))
 116                         buf_size = c->sector_size;
 117                 else
 118                         buf_size = PAGE_SIZE;
 119
 120                 /* Respect kmalloc limitations */
 121                 if (buf_size > 128*1024)
 122                         buf_size = 128*1024;
 123
 124                 D1(printk(KERN_DEBUG "Allocating readbuf of %d bytes\n", buf_size));
 125                 flashbuf = kmalloc(buf_size, GFP_KERNEL);
 126                 if (!flashbuf)
 127                         return -ENOMEM;
 128         }
 129
 130         if (jffs2_sum_active()) {
 131                 s = kmalloc(sizeof(struct jffs2_summary), GFP_KERNEL);
 132                 if (!s) {
 133                         JFFS2_WARNING("Can't allocate memory for summary\n");
 134                         return -ENOMEM;
 135                 }
 136                 memset(s, 0, sizeof(struct jffs2_summary));
 137         }
 138
 139         for (i=0; i<c->nr_blocks; i++) {
 140                 struct jffs2_eraseblock *jeb = &c->blocks[i];
 141
 142                 /* reset summary info for next eraseblock scan */
 143                 jffs2_sum_reset_collected(s);
 144
 145                 ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset),
 146                                                 buf_size, s);
 147
 148                 if (ret < 0)
 149                         goto out;
 150
 151                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 152
 153                 /* Now decide which list to put it on */
 154                 switch(ret) {
 155                 case BLK_STATE_ALLFF:
 156                         /*
 157                          * Empty block.   Since we can't be sure it
 158                          * was entirely erased, we just queue it for erase
 159                          * again.  It will be marked as such when the erase
 160                          * is complete.  Meanwhile we still count it as empty
 161                          * for later checks.
 162                          */
 163                         empty_blocks++;
 164                         list_add(&jeb->list, &c->erase_pending_list);
 165                         c->nr_erasing_blocks++;
 166                         break;
 167
 168                 case BLK_STATE_CLEANMARKER:
 169                         /* Only a CLEANMARKER node is valid */
 170                         if (!jeb->dirty_size) {
 171                                 /* It's actually free */
 172                                 list_add(&jeb->list, &c->free_list);
 173                                 c->nr_free_blocks++;
 174                         } else {
 175                                 /* Dirt */
 176                                 D1(printk(KERN_DEBUG "Adding all-dirty block at 0x%08x to erase_pending_list\n", jeb->offset));
 177                                 list_add(&jeb->list, &c->erase_pending_list);
 178                                 c->nr_erasing_blocks++;
 179                         }
 180                         break;
 181
 182                 case BLK_STATE_CLEAN:
 183                         /* Full (or almost full) of clean data. Clean list */
 184                         list_add(&jeb->list, &c->clean_list);
 185                         break;
 186
 187                 case BLK_STATE_PARTDIRTY:
 188                         /* Some data, but not full. Dirty list. */
 189                         /* We want to remember the block with most free space
 190                         and stick it in the 'nextblock' position to start writing to it. */
 191                         if (jeb->free_size > min_free(c) &&
 192                                         (!c->nextblock || c->nextblock->free_size < jeb->free_size)) {
 193                                 /* Better candidate for the next writes to go to */
 194                                 if (c->nextblock) {
 195                                         ret = file_dirty(c, c->nextblock);
 196                                         if (ret)
 197                                                 return ret;
 198                                         /* deleting summary information of the old nextblock */
 199                                         jffs2_sum_reset_collected(c->summary);
 200                                 }
 201                                 /* update collected summary information for the current nextblock */
 202                                 jffs2_sum_move_collected(c, s);
 203                                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): new nextblock = 0x%08x\n", jeb->offset));
 204                                 c->nextblock = jeb;
 205                         } else {
 206                                 ret = file_dirty(c, jeb);
 207                                 if (ret)
 208                                         return ret;
 209                         }
 210                         break;
 211
 212                 case BLK_STATE_ALLDIRTY:
 213                         /* Nothing valid - not even a clean marker. Needs erasing. */
 214                         /* For now we just put it on the erasing list. We'll start the erases later */
 215                         D1(printk(KERN_NOTICE "JFFS2: Erase block at 0x%08x is not formatted. It will be erased\n", jeb->offset));
 216                         list_add(&jeb->list, &c->erase_pending_list);
 217                         c->nr_erasing_blocks++;
 218                         break;
 219
 220                 case BLK_STATE_BADBLOCK:
 221                         D1(printk(KERN_NOTICE "JFFS2: Block at 0x%08x is bad\n", jeb->offset));
 222                         list_add(&jeb->list, &c->bad_list);
 223                         c->bad_size += c->sector_size;
 224                         c->free_size -= c->sector_size;
 225                         bad_blocks++;
 226                         break;
 227                 default:
 228                         printk(KERN_WARNING "jffs2_scan_medium(): unknown block state\n");
 229                         BUG();
 230                 }
 231         }
 232
 233         /* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
 234         if (c->nextblock && (c->nextblock->dirty_size)) {
 235                 c->nextblock->wasted_size += c->nextblock->dirty_size;
 236                 c->wasted_size += c->nextblock->dirty_size;
 237                 c->dirty_size -= c->nextblock->dirty_size;
 238                 c->nextblock->dirty_size = 0;
 239         }
 240 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 241         if (!jffs2_can_mark_obsolete(c) && c->wbuf_pagesize && c->nextblock && (c->nextblock->free_size % c->wbuf_pagesize)) {
 242                 /* If we're going to start writing into a block which already
 243                    contains data, and the end of the data isn't page-aligned,
 244                    skip a little and align it. */
 245
 246                 uint32_t skip = c->nextblock->free_size % c->wbuf_pagesize;
 247
 248                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): Skipping %d bytes in nextblock to ensure page alignment\n",
 249                           skip));
 250                 jffs2_prealloc_raw_node_refs(c, c->nextblock, 1);
 251                 jffs2_scan_dirty_space(c, c->nextblock, skip);
 252         }
 253 #endif
 254         if (c->nr_erasing_blocks) {
 255                 if ( !c->used_size && ((c->nr_free_blocks+empty_blocks+bad_blocks)!= c->nr_blocks || bad_blocks == c->nr_blocks) ) {
 256                         printk(KERN_NOTICE "Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
 257                         printk(KERN_NOTICE "empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",empty_blocks,bad_blocks,c->nr_blocks);
 258                         ret = -EIO;
 259                         goto out;
 260                 }
 261                 jffs2_erase_pending_trigger(c);
 262         }
 263         ret = 0;
 264  out:
 265         if (buf_size)
 266                 kfree(flashbuf);
 267 #ifndef __ECOS
 268         else
 269                 c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
 270 #endif
 271         if (s)
 272                 kfree(s);
 273
 274         return ret;
 275 }
 276
 277 int jffs2_fill_scan_buf (struct jffs2_sb_info *c, void *buf,
 278                                 uint32_t ofs, uint32_t len)
 279 {
 280         int ret;
 281         size_t retlen;
 282
 283         ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
 284         if (ret) {
 285                 D1(printk(KERN_WARNING "mtd->read(0x%x bytes from 0x%x) returned %d\n", len, ofs, ret));
 286                 return ret;
 287         }
 288         if (retlen < len) {
 289                 D1(printk(KERN_WARNING "Read at 0x%x gave only 0x%zx bytes\n", ofs, retlen));
 290                 return -EIO;
 291         }
 292         return 0;
 293 }
 294
 295 int jffs2_scan_classify_jeb(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
 296 {
 297         if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size
 298             && (!jeb->first_node || !ref_next(jeb->first_node)) )
 299                 return BLK_STATE_CLEANMARKER;
 300
 301         /* move blocks with max 4 byte dirty space to cleanlist */
 302         else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
 303                 c->dirty_size -= jeb->dirty_size;
 304                 c->wasted_size += jeb->dirty_size;
 305                 jeb->wasted_size += jeb->dirty_size;
 306                 jeb->dirty_size = 0;
 307                 return BLK_STATE_CLEAN;
 308         } else if (jeb->used_size || jeb->unchecked_size)
 309                 return BLK_STATE_PARTDIRTY;
 310         else
 311                 return BLK_STATE_ALLDIRTY;
 312 }
 313
 314 #ifdef CONFIG_JFFS2_FS_XATTR
 315 static int jffs2_scan_xattr_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 316                                  struct jffs2_raw_xattr *rx, uint32_t ofs,
 317                                  struct jffs2_summary *s)
 318 {
 319         struct jffs2_xattr_datum *xd;
 320         uint32_t totlen, crc;
 321         int err;
 322
 323         crc = crc32(0, rx, sizeof(struct jffs2_raw_xattr) - 4);
 324         if (crc != je32_to_cpu(rx->node_crc)) {
 325                 if (je32_to_cpu(rx->node_crc) != 0xffffffff)
 326                         JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
 327                                       ofs, je32_to_cpu(rx->node_crc), crc);
 328                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
 329                         return err;
 330                 return 0;
 331         }
 332
 333         totlen = PAD(sizeof(*rx) + rx->name_len + 1 + je16_to_cpu(rx->value_len));
 334         if (totlen != je32_to_cpu(rx->totlen)) {
 335                 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%u\n",
 336                               ofs, je32_to_cpu(rx->totlen), totlen);
 337                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
 338                         return err;
 339                 return 0;
 340         }
 341
 342         xd = jffs2_setup_xattr_datum(c, je32_to_cpu(rx->xid), je32_to_cpu(rx->version));
 343         if (IS_ERR(xd)) {
 344                 if (PTR_ERR(xd) == -EEXIST) {
 345                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rx->totlen)))))
 346                                 return err;
 347                         return 0;
 348                 }
 349                 return PTR_ERR(xd);
 350         }
 351         xd->xprefix = rx->xprefix;
 352         xd->name_len = rx->name_len;
 353         xd->value_len = je16_to_cpu(rx->value_len);
 354         xd->data_crc = je32_to_cpu(rx->data_crc);
 355
 356         xd->node = jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, NULL);
 357         /* FIXME */ xd->node->next_in_ino = (void *)xd;
 358
 359         if (jffs2_sum_active())
 360                 jffs2_sum_add_xattr_mem(s, rx, ofs - jeb->offset);
 361         dbg_xattr("scaning xdatum at %#08x (xid=%u, version=%u)\n",
 362                   ofs, xd->xid, xd->version);
 363         return 0;
 364 }
 365
 366 static int jffs2_scan_xref_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 367                                 struct jffs2_raw_xref *rr, uint32_t ofs,
 368                                 struct jffs2_summary *s)
 369 {
 370         struct jffs2_xattr_ref *ref;
 371         uint32_t crc;
 372         int err;
 373
 374         crc = crc32(0, rr, sizeof(*rr) - 4);
 375         if (crc != je32_to_cpu(rr->node_crc)) {
 376                 if (je32_to_cpu(rr->node_crc) != 0xffffffff)
 377                         JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
 378                                       ofs, je32_to_cpu(rr->node_crc), crc);
 379                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rr->totlen)))))
 380                         return err;
 381                 return 0;
 382         }
 383
 384         if (PAD(sizeof(struct jffs2_raw_xref)) != je32_to_cpu(rr->totlen)) {
 385                 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%zd\n",
 386                               ofs, je32_to_cpu(rr->totlen),
 387                               PAD(sizeof(struct jffs2_raw_xref)));
 388                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rr->totlen))))
 389                         return err;
 390                 return 0;
 391         }
 392
 393         ref = jffs2_alloc_xattr_ref();
 394         if (!ref)
 395                 return -ENOMEM;
 396
 397         /* BEFORE jffs2_build_xattr_subsystem() called,
 398          * ref->xid is used to store 32bit xid, xd is not used
 399          * ref->ino is used to store 32bit inode-number, ic is not used
 400          * Thoes variables are declared as union, thus using those
 401          * are exclusive. In a similar way, ref->next is temporarily
 402          * used to chain all xattr_ref object. It's re-chained to
 403          * jffs2_inode_cache in jffs2_build_xattr_subsystem() correctly.
 404          */
 405         ref->ino = je32_to_cpu(rr->ino);
 406         ref->xid = je32_to_cpu(rr->xid);
 407         ref->next = c->xref_temp;
 408         c->xref_temp = ref;
 409
 410         ref->node = jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(rr->totlen)), NULL);
 411         /* FIXME */ ref->node->next_in_ino = (void *)ref;
 412
 413         if (jffs2_sum_active())
 414                 jffs2_sum_add_xref_mem(s, rr, ofs - jeb->offset);
 415         dbg_xattr("scan xref at %#08x (xid=%u, ino=%u)\n",
 416                   ofs, ref->xid, ref->ino);
 417         return 0;
 418 }
 419 #endif
 420
 421 /* Called with 'buf_size == 0' if buf is in fact a pointer _directly_ into
 422    the flash, XIP-style */
 423 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 424                                   unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) {
 425         struct jffs2_unknown_node *node;
 426         struct jffs2_unknown_node crcnode;
 427         uint32_t ofs, prevofs;
 428         uint32_t hdr_crc, buf_ofs, buf_len;
 429         int err;
 430         int noise = 0;
 431
 432
 433 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 434         int cleanmarkerfound = 0;
 435 #endif
 436
 437         ofs = jeb->offset;
 438         prevofs = jeb->offset - 1;
 439
 440         D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs));
 441
 442 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 443         if (jffs2_cleanmarker_oob(c)) {
 444                 int ret = jffs2_check_nand_cleanmarker(c, jeb);
 445                 D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n",ret));
 446                 /* Even if it's not found, we still scan to see
 447                    if the block is empty. We use this information
 448                    to decide whether to erase it or not. */
 449                 switch (ret) {
 450                 case 0:         cleanmarkerfound = 1; break;
 451                 case 1:         break;
 452                 case 2:         return BLK_STATE_BADBLOCK;
 453                 case 3:         return BLK_STATE_ALLDIRTY; /* Block has failed to erase min. once */
 454                 default:        return ret;
 455                 }
 456         }
 457 #endif
 458
 459         if (jffs2_sum_active()) {
 460                 struct jffs2_sum_marker *sm;
 461                 void *sumptr = NULL;
 462                 uint32_t sumlen;
 463
 464                 if (!buf_size) {
 465                         /* XIP case. Just look, point at the summary if it's there */
 466                         sm = (void *)buf + c->sector_size - sizeof(*sm);
 467                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
 468                                 sumptr = buf + je32_to_cpu(sm->offset);
 469                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
 470                         }
 471                 } else {
 472                         /* If NAND flash, read a whole page of it. Else just the end */
 473                         if (c->wbuf_pagesize)
 474                                 buf_len = c->wbuf_pagesize;
 475                         else
 476                                 buf_len = sizeof(*sm);
 477
 478                         /* Read as much as we want into the _end_ of the preallocated buffer */
 479                         err = jffs2_fill_scan_buf(c, buf + buf_size - buf_len,
 480                                                   jeb->offset + c->sector_size - buf_len,
 481                                                   buf_len);
 482                         if (err)
 483                                 return err;
 484
 485                         sm = (void *)buf + buf_size - sizeof(*sm);
 486                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
 487                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
 488                                 sumptr = buf + buf_size - sumlen;
 489
 490                                 /* Now, make sure the summary itself is available */
 491                                 if (sumlen > buf_size) {
 492                                         /* Need to kmalloc for this. */
 493                                         sumptr = kmalloc(sumlen, GFP_KERNEL);
 494                                         if (!sumptr)
 495                                                 return -ENOMEM;
 496                                         memcpy(sumptr + sumlen - buf_len, buf + buf_size - buf_len, buf_len);
 497                                 }
 498                                 if (buf_len < sumlen) {
 499                                         /* Need to read more so that the entire summary node is present */
 500                                         err = jffs2_fill_scan_buf(c, sumptr,
 501                                                                   jeb->offset + c->sector_size - sumlen,
 502                                                                   sumlen - buf_len);
 503                                         if (err)
 504                                                 return err;
 505                                 }
 506                         }
 507
 508                 }
 509
 510                 if (sumptr) {
 511                         err = jffs2_sum_scan_sumnode(c, jeb, sumptr, sumlen, &pseudo_random);
 512
 513                         if (buf_size && sumlen > buf_size)
 514                                 kfree(sumptr);
 515                         /* If it returns with a real error, bail.
 516                            If it returns positive, that's a block classification
 517                            (i.e. BLK_STATE_xxx) so return that too.
 518                            If it returns zero, fall through to full scan. */
 519                         if (err)
 520                                 return err;
 521                 }
 522         }
 523
 524         buf_ofs = jeb->offset;
 525
 526         if (!buf_size) {
 527                 /* This is the XIP case -- we're reading _directly_ from the flash chip */
 528                 buf_len = c->sector_size;
 529         } else {
 530                 buf_len = EMPTY_SCAN_SIZE(c->sector_size);
 531                 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
 532                 if (err)
 533                         return err;
 534         }
 535
 536         /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
 537         ofs = 0;
 538
 539         /* Scan only 4KiB of 0xFF before declaring it's empty */
 540         while(ofs < EMPTY_SCAN_SIZE(c->sector_size) && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
 541                 ofs += 4;
 542
 543         if (ofs == EMPTY_SCAN_SIZE(c->sector_size)) {
 544 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 545                 if (jffs2_cleanmarker_oob(c)) {
 546                         /* scan oob, take care of cleanmarker */
 547                         int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
 548                         D2(printk(KERN_NOTICE "jffs2_check_oob_empty returned %d\n",ret));
 549                         switch (ret) {
 550                         case 0:         return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
 551                         case 1:         return BLK_STATE_ALLDIRTY;
 552                         default:        return ret;
 553                         }
 554                 }
 555 #endif
 556                 D1(printk(KERN_DEBUG "Block at 0x%08x is empty (erased)\n", jeb->offset));
 557                 if (c->cleanmarker_size == 0)
 558                         return BLK_STATE_CLEANMARKER;   /* don't bother with re-erase */
 559                 else
 560                         return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
 561         }
 562         if (ofs) {
 563                 D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset,
 564                           jeb->offset + ofs));
 565                 if ((err = jffs2_prealloc_raw_node_refs(c, jeb, 1)))
 566                         return err;
 567                 if ((err = jffs2_scan_dirty_space(c, jeb, ofs)))
 568                         return err;
 569         }
 570
 571         /* Now ofs is a complete physical flash offset as it always was... */
 572         ofs += jeb->offset;
 573
 574         noise = 10;
 575
 576         dbg_summary("no summary found in jeb 0x%08x. Apply original scan.\n",jeb->offset);
 577
 578 scan_more:
 579         while(ofs < jeb->offset + c->sector_size) {
 580
 581                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 582
 583                 /* Make sure there are node refs available for use */
 584                 err = jffs2_prealloc_raw_node_refs(c, jeb, 2);
 585                 if (err)
 586                         return err;
 587
 588                 cond_resched();
 589
 590                 if (ofs & 3) {
 591                         printk(KERN_WARNING "Eep. ofs 0x%08x not word-aligned!\n", ofs);
 592                         ofs = PAD(ofs);
 593                         continue;
 594                 }
 595                 if (ofs == prevofs) {
 596                         printk(KERN_WARNING "ofs 0x%08x has already been seen. Skipping\n", ofs);
 597                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 598                                 return err;
 599                         ofs += 4;
 600                         continue;
 601                 }
 602                 prevofs = ofs;
 603
 604                 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
 605                         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),
 606                                   jeb->offset, c->sector_size, ofs, sizeof(*node)));
 607                         if ((err = jffs2_scan_dirty_space(c, jeb, (jeb->offset + c->sector_size)-ofs)))
 608                                 return err;
 609                         break;
 610                 }
 611
 612                 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
 613                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 614                         D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
 615                                   sizeof(struct jffs2_unknown_node), buf_len, ofs));
 616                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 617                         if (err)
 618                                 return err;
 619                         buf_ofs = ofs;
 620                 }
 621
 622                 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
 623
 624                 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
 625                         uint32_t inbuf_ofs;
 626                         uint32_t empty_start;
 627
 628                         empty_start = ofs;
 629                         ofs += 4;
 630
 631                         D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs));
 632                 more_empty:
 633                         inbuf_ofs = ofs - buf_ofs;
 634                         while (inbuf_ofs < buf_len) {
 635                                 if (*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff) {
 636                                         printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n",
 637                                                empty_start, ofs);
 638                                         if ((err = jffs2_scan_dirty_space(c, jeb, ofs-empty_start)))
 639                                                 return err;
 640                                         goto scan_more;
 641                                 }
 642
 643                                 inbuf_ofs+=4;
 644                                 ofs += 4;
 645                         }
 646                         /* Ran off end. */
 647                         D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs));
 648
 649                         /* If we're only checking the beginning of a block with a cleanmarker,
 650                            bail now */
 651                         if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&
 652                             c->cleanmarker_size && !jeb->dirty_size && !ref_next(jeb->first_node)) {
 653                                 D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE(c->sector_size)));
 654                                 return BLK_STATE_CLEANMARKER;
 655                         }
 656
 657                         /* See how much more there is to read in this eraseblock... */
 658                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 659                         if (!buf_len) {
 660                                 /* No more to read. Break out of main loop without marking
 661                                    this range of empty space as dirty (because it's not) */
 662                                 D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block. Treating as free_space\n",
 663                                           empty_start));
 664                                 break;
 665                         }
 666                         D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs));
 667                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 668                         if (err)
 669                                 return err;
 670                         buf_ofs = ofs;
 671                         goto more_empty;
 672                 }
 673
 674                 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
 675                         printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n", ofs);
 676                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 677                                 return err;
 678                         ofs += 4;
 679                         continue;
 680                 }
 681                 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
 682                         D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs));
 683                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 684                                 return err;
 685                         ofs += 4;
 686                         continue;
 687                 }
 688                 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
 689                         printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08x\n", ofs);
 690                         printk(KERN_WARNING "You cannot use older JFFS2 filesystems with newer kernels\n");
 691                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 692                                 return err;
 693                         ofs += 4;
 694                         continue;
 695                 }
 696                 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
 697                         /* OK. We're out of possibilities. Whinge and move on */
 698                         noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n",
 699                                      JFFS2_MAGIC_BITMASK, ofs,
 700                                      je16_to_cpu(node->magic));
 701                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 702                                 return err;
 703                         ofs += 4;
 704                         continue;
 705                 }
 706                 /* We seem to have a node of sorts. Check the CRC */
 707                 crcnode.magic = node->magic;
 708                 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
 709                 crcnode.totlen = node->totlen;
 710                 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
 711
 712                 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
 713                         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",
 714                                      ofs, je16_to_cpu(node->magic),
 715                                      je16_to_cpu(node->nodetype),
 716                                      je32_to_cpu(node->totlen),
 717                                      je32_to_cpu(node->hdr_crc),
 718                                      hdr_crc);
 719                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 720                                 return err;
 721                         ofs += 4;
 722                         continue;
 723                 }
 724
 725                 if (ofs + je32_to_cpu(node->totlen) >
 726                     jeb->offset + c->sector_size) {
 727                         /* Eep. Node goes over the end of the erase block. */
 728                         printk(KERN_WARNING "Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
 729                                ofs, je32_to_cpu(node->totlen));
 730                         printk(KERN_WARNING "Perhaps the file system was created with the wrong erase size?\n");
 731                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 732                                 return err;
 733                         ofs += 4;
 734                         continue;
 735                 }
 736
 737                 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
 738                         /* Wheee. This is an obsoleted node */
 739                         D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs));
 740                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 741                                 return err;
 742                         ofs += PAD(je32_to_cpu(node->totlen));
 743                         continue;
 744                 }
 745
 746                 switch(je16_to_cpu(node->nodetype)) {
 747                 case JFFS2_NODETYPE_INODE:
 748                         if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
 749                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 750                                 D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
 751                                           sizeof(struct jffs2_raw_inode), buf_len, ofs));
 752                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 753                                 if (err)
 754                                         return err;
 755                                 buf_ofs = ofs;
 756                                 node = (void *)buf;
 757                         }
 758                         err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs, s);
 759                         if (err) return err;
 760                         ofs += PAD(je32_to_cpu(node->totlen));
 761                         break;
 762
 763                 case JFFS2_NODETYPE_DIRENT:
 764                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 765                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 766                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
 767                                           je32_to_cpu(node->totlen), buf_len, ofs));
 768                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 769                                 if (err)
 770                                         return err;
 771                                 buf_ofs = ofs;
 772                                 node = (void *)buf;
 773                         }
 774                         err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs, s);
 775                         if (err) return err;
 776                         ofs += PAD(je32_to_cpu(node->totlen));
 777                         break;
 778
 779 #ifdef CONFIG_JFFS2_FS_XATTR
 780                 case JFFS2_NODETYPE_XATTR:
 781                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 782                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 783                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (xattr node)"
 784                                           " left to end of buf. Reading 0x%x at 0x%08x\n",
 785                                           je32_to_cpu(node->totlen), buf_len, ofs));
 786                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 787                                 if (err)
 788                                         return err;
 789                                 buf_ofs = ofs;
 790                                 node = (void *)buf;
 791                         }
 792                         err = jffs2_scan_xattr_node(c, jeb, (void *)node, ofs, s);
 793                         if (err)
 794                                 return err;
 795                         ofs += PAD(je32_to_cpu(node->totlen));
 796                         break;
 797                 case JFFS2_NODETYPE_XREF:
 798                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 799                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 800                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (xref node)"
 801                                           " left to end of buf. Reading 0x%x at 0x%08x\n",
 802                                           je32_to_cpu(node->totlen), buf_len, ofs));
 803                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 804                                 if (err)
 805                                         return err;
 806                                 buf_ofs = ofs;
 807                                 node = (void *)buf;
 808                         }
 809                         err = jffs2_scan_xref_node(c, jeb, (void *)node, ofs, s);
 810                         if (err)
 811                                 return err;
 812                         ofs += PAD(je32_to_cpu(node->totlen));
 813                         break;
 814 #endif  /* CONFIG_JFFS2_FS_XATTR */
 815
 816                 case JFFS2_NODETYPE_CLEANMARKER:
 817                         D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs));
 818                         if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
 819                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n",
 820                                        ofs, je32_to_cpu(node->totlen), c->cleanmarker_size);
 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 if (jeb->first_node) {
 825                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n", ofs, jeb->offset);
 826                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
 827                                         return err;
 828                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 829                         } else {
 830                                 jffs2_link_node_ref(c, jeb, ofs | REF_NORMAL, c->cleanmarker_size, NULL);
 831
 832                                 ofs += PAD(c->cleanmarker_size);
 833                         }
 834                         break;
 835
 836                 case JFFS2_NODETYPE_PADDING:
 837                         if (jffs2_sum_active())
 838                                 jffs2_sum_add_padding_mem(s, je32_to_cpu(node->totlen));
 839                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 840                                 return err;
 841                         ofs += PAD(je32_to_cpu(node->totlen));
 842                         break;
 843
 844                 default:
 845                         switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
 846                         case JFFS2_FEATURE_ROCOMPAT:
 847                                 printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 848                                 c->flags |= JFFS2_SB_FLAG_RO;
 849                                 if (!(jffs2_is_readonly(c)))
 850                                         return -EROFS;
 851                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 852                                         return err;
 853                                 ofs += PAD(je32_to_cpu(node->totlen));
 854                                 break;
 855
 856                         case JFFS2_FEATURE_INCOMPAT:
 857                                 printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 858                                 return -EINVAL;
 859
 860                         case JFFS2_FEATURE_RWCOMPAT_DELETE:
 861                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 862                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 863                                         return err;
 864                                 ofs += PAD(je32_to_cpu(node->totlen));
 865                                 break;
 866
 867                         case JFFS2_FEATURE_RWCOMPAT_COPY: {
 868                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 869
 870                                 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(node->totlen)), NULL);
 871
 872                                 /* We can't summarise nodes we don't grok */
 873                                 jffs2_sum_disable_collecting(s);
 874                                 ofs += PAD(je32_to_cpu(node->totlen));
 875                                 break;
 876                                 }
 877                         }
 878                 }
 879         }
 880
 881         if (jffs2_sum_active()) {
 882                 if (PAD(s->sum_size + JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size) {
 883                         dbg_summary("There is not enough space for "
 884                                 "summary information, disabling for this jeb!\n");
 885                         jffs2_sum_disable_collecting(s);
 886                 }
 887         }
 888
 889         D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x, wasted 0x%08x\n",
 890                   jeb->offset,jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size, jeb->wasted_size));
 891
 892         /* mark_node_obsolete can add to wasted !! */
 893         if (jeb->wasted_size) {
 894                 jeb->dirty_size += jeb->wasted_size;
 895                 c->dirty_size += jeb->wasted_size;
 896                 c->wasted_size -= jeb->wasted_size;
 897                 jeb->wasted_size = 0;
 898         }
 899
 900         return jffs2_scan_classify_jeb(c, jeb);
 901 }
 902
 903 struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
 904 {
 905         struct jffs2_inode_cache *ic;
 906
 907         ic = jffs2_get_ino_cache(c, ino);
 908         if (ic)
 909                 return ic;
 910
 911         if (ino > c->highest_ino)
 912                 c->highest_ino = ino;
 913
 914         ic = jffs2_alloc_inode_cache();
 915         if (!ic) {
 916                 printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n");
 917                 return NULL;
 918         }
 919         memset(ic, 0, sizeof(*ic));
 920
 921         ic->ino = ino;
 922         ic->nodes = (void *)ic;
 923         jffs2_add_ino_cache(c, ic);
 924         if (ino == 1)
 925                 ic->nlink = 1;
 926         return ic;
 927 }
 928
 929 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 930                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s)
 931 {
 932         struct jffs2_inode_cache *ic;
 933         uint32_t ino = je32_to_cpu(ri->ino);
 934         int err;
 935
 936         D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs));
 937
 938         /* We do very little here now. Just check the ino# to which we should attribute
 939            this node; we can do all the CRC checking etc. later. There's a tradeoff here --
 940            we used to scan the flash once only, reading everything we want from it into
 941            memory, then building all our in-core data structures and freeing the extra
 942            information. Now we allow the first part of the mount to complete a lot quicker,
 943            but we have to go _back_ to the flash in order to finish the CRC checking, etc.
 944            Which means that the _full_ amount of time to get to proper write mode with GC
 945            operational may actually be _longer_ than before. Sucks to be me. */
 946
 947         ic = jffs2_get_ino_cache(c, ino);
 948         if (!ic) {
 949                 /* Inocache get failed. Either we read a bogus ino# or it's just genuinely the
 950                    first node we found for this inode. Do a CRC check to protect against the former
 951                    case */
 952                 uint32_t crc = crc32(0, ri, sizeof(*ri)-8);
 953
 954                 if (crc != je32_to_cpu(ri->node_crc)) {
 955                         printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 956                                ofs, je32_to_cpu(ri->node_crc), crc);
 957                         /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
 958                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(ri->totlen)))))
 959                                 return err;
 960                         return 0;
 961                 }
 962                 ic = jffs2_scan_make_ino_cache(c, ino);
 963                 if (!ic)
 964                         return -ENOMEM;
 965         }
 966
 967         /* Wheee. It worked */
 968         jffs2_link_node_ref(c, jeb, ofs | REF_UNCHECKED, PAD(je32_to_cpu(ri->totlen)), ic);
 969
 970         D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
 971                   je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
 972                   je32_to_cpu(ri->offset),
 973                   je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize)));
 974
 975         pseudo_random += je32_to_cpu(ri->version);
 976
 977         if (jffs2_sum_active()) {
 978                 jffs2_sum_add_inode_mem(s, ri, ofs - jeb->offset);
 979         }
 980
 981         return 0;
 982 }
 983
 984 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 985                                   struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s)
 986 {
 987         struct jffs2_full_dirent *fd;
 988         struct jffs2_inode_cache *ic;
 989         uint32_t crc;
 990         int err;
 991
 992         D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs));
 993
 994         /* We don't get here unless the node is still valid, so we don't have to
 995            mask in the ACCURATE bit any more. */
 996         crc = crc32(0, rd, sizeof(*rd)-8);
 997
 998         if (crc != je32_to_cpu(rd->node_crc)) {
 999                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1000                        ofs, je32_to_cpu(rd->node_crc), crc);
1001                 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
1002                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1003                         return err;
1004                 return 0;
1005         }
1006
1007         pseudo_random += je32_to_cpu(rd->version);
1008
1009         fd = jffs2_alloc_full_dirent(rd->nsize+1);
1010         if (!fd) {
1011                 return -ENOMEM;
1012         }
1013         memcpy(&fd->name, rd->name, rd->nsize);
1014         fd->name[rd->nsize] = 0;
1015
1016         crc = crc32(0, fd->name, rd->nsize);
1017         if (crc != je32_to_cpu(rd->name_crc)) {
1018                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1019                        ofs, je32_to_cpu(rd->name_crc), crc);
1020                 D1(printk(KERN_NOTICE "Name for which CRC failed is (now) '%s', ino #%d\n", fd->name, je32_to_cpu(rd->ino)));
1021                 jffs2_free_full_dirent(fd);
1022                 /* FIXME: Why do we believe totlen? */
1023                 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
1024                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1025                         return err;
1026                 return 0;
1027         }
1028         ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
1029         if (!ic) {
1030                 jffs2_free_full_dirent(fd);
1031                 return -ENOMEM;
1032         }
1033
1034         fd->raw = jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(rd->totlen)), ic);
1035
1036         fd->next = NULL;
1037         fd->version = je32_to_cpu(rd->version);
1038         fd->ino = je32_to_cpu(rd->ino);
1039         fd->nhash = full_name_hash(fd->name, rd->nsize);
1040         fd->type = rd->type;
1041         jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
1042
1043         if (jffs2_sum_active()) {
1044                 jffs2_sum_add_dirent_mem(s, rd, ofs - jeb->offset);
1045         }
1046
1047         return 0;
1048 }
1049
1050 static int count_list(struct list_head *l)
1051 {
1052         uint32_t count = 0;
1053         struct list_head *tmp;
1054
1055         list_for_each(tmp, l) {
1056                 count++;
1057         }
1058         return count;
1059 }
1060
1061 /* Note: This breaks if list_empty(head). I don't care. You
1062    might, if you copy this code and use it elsewhere :) */
1063 static void rotate_list(struct list_head *head, uint32_t count)
1064 {
1065         struct list_head *n = head->next;
1066
1067         list_del(head);
1068         while(count--) {
1069                 n = n->next;
1070         }
1071         list_add(head, n);
1072 }
1073
1074 void jffs2_rotate_lists(struct jffs2_sb_info *c)
1075 {
1076         uint32_t x;
1077         uint32_t rotateby;
1078
1079         x = count_list(&c->clean_list);
1080         if (x) {
1081                 rotateby = pseudo_random % x;
1082                 rotate_list((&c->clean_list), rotateby);
1083         }
1084
1085         x = count_list(&c->very_dirty_list);
1086         if (x) {
1087                 rotateby = pseudo_random % x;
1088                 rotate_list((&c->very_dirty_list), rotateby);
1089         }
1090
1091         x = count_list(&c->dirty_list);
1092         if (x) {
1093                 rotateby = pseudo_random % x;
1094                 rotate_list((&c->dirty_list), rotateby);
1095         }
1096
1097         x = count_list(&c->erasable_list);
1098         if (x) {
1099                 rotateby = pseudo_random % x;
1100                 rotate_list((&c->erasable_list), rotateby);
1101         }
1102
1103         if (c->nr_erasing_blocks) {
1104                 rotateby = pseudo_random % c->nr_erasing_blocks;
1105                 rotate_list((&c->erase_pending_list), rotateby);
1106         }
1107
1108         if (c->nr_free_blocks) {
1109                 rotateby = pseudo_random % c->nr_free_blocks;
1110                 rotate_list((&c->free_list), rotateby);
1111         }
1112 }