fs/jffs2/scan.c

   1 /*
   2  * JFFS2 -- Journalling Flash File System, Version 2.
   3  *
   4  * Copyright (C) 2001-2003 Red Hat, Inc.
   5  *
   6  * Created by David Woodhouse <dwmw2@infradead.org>
   7  *
   8  * For licensing information, see the file 'LICENCE' in this directory.
   9  *
  10  * $Id: scan.c,v 1.125 2005/09/30 13:59:13 dedekind Exp $
  11  *
  12  */
  13 #include <linux/kernel.h>
  14 #include <linux/sched.h>
  15 #include <linux/slab.h>
  16 #include <linux/mtd/mtd.h>
  17 #include <linux/pagemap.h>
  18 #include <linux/crc32.h>
  19 #include <linux/compiler.h>
  20 #include "nodelist.h"
  21 #include "summary.h"
  22 #include "debug.h"
  23
  24 #define DEFAULT_EMPTY_SCAN_SIZE 1024
  25
  26 #define noisy_printk(noise, args...) do { \
  27         if (*(noise)) { \
  28                 printk(KERN_NOTICE args); \
  29                  (*(noise))--; \
  30                  if (!(*(noise))) { \
  31                          printk(KERN_NOTICE "Further such events for this erase block will not be printed\n"); \
  32                  } \
  33         } \
  34 } while(0)
  35
  36 static uint32_t pseudo_random;
  37
  38 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  39                                   unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s);
  40
  41 /* These helper functions _must_ increase ofs and also do the dirty/used space accounting.
  42  * Returning an error will abort the mount - bad checksums etc. should just mark the space
  43  * as dirty.
  44  */
  45 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  46                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s);
  47 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  48                                  struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s);
  49
  50 static inline int min_free(struct jffs2_sb_info *c)
  51 {
  52         uint32_t min = 2 * sizeof(struct jffs2_raw_inode);
  53 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
  54         if (!jffs2_can_mark_obsolete(c) && min < c->wbuf_pagesize)
  55                 return c->wbuf_pagesize;
  56 #endif
  57         return min;
  58
  59 }
  60
  61 static inline uint32_t EMPTY_SCAN_SIZE(uint32_t sector_size) {
  62         if (sector_size < DEFAULT_EMPTY_SCAN_SIZE)
  63                 return sector_size;
  64         else
  65                 return DEFAULT_EMPTY_SCAN_SIZE;
  66 }
  67
  68 int jffs2_scan_medium(struct jffs2_sb_info *c)
  69 {
  70         int i, ret;
  71         uint32_t empty_blocks = 0, bad_blocks = 0;
  72         unsigned char *flashbuf = NULL;
  73         uint32_t buf_size = 0;
  74         struct jffs2_summary *s = NULL; /* summary info collected by the scan process */
  75 #ifndef __ECOS
  76         size_t pointlen;
  77
  78         if (c->mtd->point) {
  79                 ret = c->mtd->point (c->mtd, 0, c->mtd->size, &pointlen, &flashbuf);
  80                 if (!ret && pointlen < c->mtd->size) {
  81                         /* Don't muck about if it won't let us point to the whole flash */
  82                         D1(printk(KERN_DEBUG "MTD point returned len too short: 0x%zx\n", pointlen));
  83                         c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
  84                         flashbuf = NULL;
  85                 }
  86                 if (ret)
  87                         D1(printk(KERN_DEBUG "MTD point failed %d\n", ret));
  88         }
  89 #endif
  90         if (!flashbuf) {
  91                 /* For NAND it's quicker to read a whole eraseblock at a time,
  92                    apparently */
  93                 if (jffs2_cleanmarker_oob(c))
  94                         buf_size = c->sector_size;
  95                 else
  96                         buf_size = PAGE_SIZE;
  97
  98                 /* Respect kmalloc limitations */
  99                 if (buf_size > 128*1024)
 100                         buf_size = 128*1024;
 101
 102                 D1(printk(KERN_DEBUG "Allocating readbuf of %d bytes\n", buf_size));
 103                 flashbuf = kmalloc(buf_size, GFP_KERNEL);
 104                 if (!flashbuf)
 105                         return -ENOMEM;
 106         }
 107
 108         if (jffs2_sum_active()) {
 109                 s = kmalloc(sizeof(struct jffs2_summary), GFP_KERNEL);
 110                 if (!s) {
 111                         JFFS2_WARNING("Can't allocate memory for summary\n");
 112                         return -ENOMEM;
 113                 }
 114                 memset(s, 0, sizeof(struct jffs2_summary));
 115         }
 116
 117         for (i=0; i<c->nr_blocks; i++) {
 118                 struct jffs2_eraseblock *jeb = &c->blocks[i];
 119
 120                 /* reset summary info for next eraseblock scan */
 121                 jffs2_sum_reset_collected(s);
 122
 123                 ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset),
 124                                                 buf_size, s);
 125
 126                 if (ret < 0)
 127                         goto out;
 128
 129                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 130
 131                 /* Now decide which list to put it on */
 132                 switch(ret) {
 133                 case BLK_STATE_ALLFF:
 134                         /*
 135                          * Empty block.   Since we can't be sure it
 136                          * was entirely erased, we just queue it for erase
 137                          * again.  It will be marked as such when the erase
 138                          * is complete.  Meanwhile we still count it as empty
 139                          * for later checks.
 140                          */
 141                         empty_blocks++;
 142                         list_add(&jeb->list, &c->erase_pending_list);
 143                         c->nr_erasing_blocks++;
 144                         break;
 145
 146                 case BLK_STATE_CLEANMARKER:
 147                         /* Only a CLEANMARKER node is valid */
 148                         if (!jeb->dirty_size) {
 149                                 /* It's actually free */
 150                                 list_add(&jeb->list, &c->free_list);
 151                                 c->nr_free_blocks++;
 152                         } else {
 153                                 /* Dirt */
 154                                 D1(printk(KERN_DEBUG "Adding all-dirty block at 0x%08x to erase_pending_list\n", jeb->offset));
 155                                 list_add(&jeb->list, &c->erase_pending_list);
 156                                 c->nr_erasing_blocks++;
 157                         }
 158                         break;
 159
 160                 case BLK_STATE_CLEAN:
 161                         /* Full (or almost full) of clean data. Clean list */
 162                         list_add(&jeb->list, &c->clean_list);
 163                         break;
 164
 165                 case BLK_STATE_PARTDIRTY:
 166                         /* Some data, but not full. Dirty list. */
 167                         /* We want to remember the block with most free space
 168                         and stick it in the 'nextblock' position to start writing to it. */
 169                         if (jeb->free_size > min_free(c) &&
 170                                         (!c->nextblock || c->nextblock->free_size < jeb->free_size)) {
 171                                 /* Better candidate for the next writes to go to */
 172                                 if (c->nextblock) {
 173                                         c->nextblock->dirty_size += c->nextblock->free_size + c->nextblock->wasted_size;
 174                                         c->dirty_size += c->nextblock->free_size + c->nextblock->wasted_size;
 175                                         c->free_size -= c->nextblock->free_size;
 176                                         c->wasted_size -= c->nextblock->wasted_size;
 177                                         c->nextblock->free_size = c->nextblock->wasted_size = 0;
 178                                         if (VERYDIRTY(c, c->nextblock->dirty_size)) {
 179                                                 list_add(&c->nextblock->list, &c->very_dirty_list);
 180                                         } else {
 181                                                 list_add(&c->nextblock->list, &c->dirty_list);
 182                                         }
 183                                         /* deleting summary information of the old nextblock */
 184                                         jffs2_sum_reset_collected(c->summary);
 185                                 }
 186                                 /* update collected summary infromation for the current nextblock */
 187                                 jffs2_sum_move_collected(c, s);
 188                                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): new nextblock = 0x%08x\n", jeb->offset));
 189                                 c->nextblock = jeb;
 190                         } else {
 191                                 jeb->dirty_size += jeb->free_size + jeb->wasted_size;
 192                                 c->dirty_size += jeb->free_size + jeb->wasted_size;
 193                                 c->free_size -= jeb->free_size;
 194                                 c->wasted_size -= jeb->wasted_size;
 195                                 jeb->free_size = jeb->wasted_size = 0;
 196                                 if (VERYDIRTY(c, jeb->dirty_size)) {
 197                                         list_add(&jeb->list, &c->very_dirty_list);
 198                                 } else {
 199                                         list_add(&jeb->list, &c->dirty_list);
 200                                 }
 201                         }
 202                         break;
 203
 204                 case BLK_STATE_ALLDIRTY:
 205                         /* Nothing valid - not even a clean marker. Needs erasing. */
 206                         /* For now we just put it on the erasing list. We'll start the erases later */
 207                         D1(printk(KERN_NOTICE "JFFS2: Erase block at 0x%08x is not formatted. It will be erased\n", jeb->offset));
 208                         list_add(&jeb->list, &c->erase_pending_list);
 209                         c->nr_erasing_blocks++;
 210                         break;
 211
 212                 case BLK_STATE_BADBLOCK:
 213                         D1(printk(KERN_NOTICE "JFFS2: Block at 0x%08x is bad\n", jeb->offset));
 214                         list_add(&jeb->list, &c->bad_list);
 215                         c->bad_size += c->sector_size;
 216                         c->free_size -= c->sector_size;
 217                         bad_blocks++;
 218                         break;
 219                 default:
 220                         printk(KERN_WARNING "jffs2_scan_medium(): unknown block state\n");
 221                         BUG();
 222                 }
 223         }
 224
 225         /* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
 226         if (c->nextblock && (c->nextblock->dirty_size)) {
 227                 c->nextblock->wasted_size += c->nextblock->dirty_size;
 228                 c->wasted_size += c->nextblock->dirty_size;
 229                 c->dirty_size -= c->nextblock->dirty_size;
 230                 c->nextblock->dirty_size = 0;
 231         }
 232 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 233         if (!jffs2_can_mark_obsolete(c) && c->wbuf_pagesize && c->nextblock && (c->nextblock->free_size % c->wbuf_pagesize)) {
 234                 /* If we're going to start writing into a block which already
 235                    contains data, and the end of the data isn't page-aligned,
 236                    skip a little and align it. */
 237
 238                 uint32_t skip = c->nextblock->free_size % c->wbuf_pagesize;
 239
 240                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): Skipping %d bytes in nextblock to ensure page alignment\n",
 241                           skip));
 242                 c->nextblock->wasted_size += skip;
 243                 c->wasted_size += skip;
 244
 245                 c->nextblock->free_size -= skip;
 246                 c->free_size -= skip;
 247         }
 248 #endif
 249         if (c->nr_erasing_blocks) {
 250                 if ( !c->used_size && ((c->nr_free_blocks+empty_blocks+bad_blocks)!= c->nr_blocks || bad_blocks == c->nr_blocks) ) {
 251                         printk(KERN_NOTICE "Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
 252                         printk(KERN_NOTICE "empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",empty_blocks,bad_blocks,c->nr_blocks);
 253                         ret = -EIO;
 254                         goto out;
 255                 }
 256                 jffs2_erase_pending_trigger(c);
 257         }
 258         ret = 0;
 259  out:
 260         if (buf_size)
 261                 kfree(flashbuf);
 262 #ifndef __ECOS
 263         else
 264                 c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
 265 #endif
 266         if (s)
 267                 kfree(s);
 268
 269         return ret;
 270 }
 271
 272 int jffs2_fill_scan_buf (struct jffs2_sb_info *c, void *buf,
 273                                 uint32_t ofs, uint32_t len)
 274 {
 275         int ret;
 276         size_t retlen;
 277
 278         ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
 279         if (ret) {
 280                 D1(printk(KERN_WARNING "mtd->read(0x%x bytes from 0x%x) returned %d\n", len, ofs, ret));
 281                 return ret;
 282         }
 283         if (retlen < len) {
 284                 D1(printk(KERN_WARNING "Read at 0x%x gave only 0x%zx bytes\n", ofs, retlen));
 285                 return -EIO;
 286         }
 287         return 0;
 288 }
 289
 290 int jffs2_scan_classify_jeb(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
 291 {
 292         if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size
 293                 && (!jeb->first_node || !jeb->first_node->next_phys) )
 294                 return BLK_STATE_CLEANMARKER;
 295
 296         /* move blocks with max 4 byte dirty space to cleanlist */
 297         else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
 298                 c->dirty_size -= jeb->dirty_size;
 299                 c->wasted_size += jeb->dirty_size;
 300                 jeb->wasted_size += jeb->dirty_size;
 301                 jeb->dirty_size = 0;
 302                 return BLK_STATE_CLEAN;
 303         } else if (jeb->used_size || jeb->unchecked_size)
 304                 return BLK_STATE_PARTDIRTY;
 305         else
 306                 return BLK_STATE_ALLDIRTY;
 307 }
 308
 309 #ifdef CONFIG_JFFS2_FS_XATTR
 310 static int jffs2_scan_xattr_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 311                                  struct jffs2_raw_xattr *rx, uint32_t ofs,
 312                                  struct jffs2_summary *s)
 313 {
 314         struct jffs2_xattr_datum *xd;
 315         struct jffs2_raw_node_ref *raw;
 316         uint32_t totlen, crc;
 317
 318         crc = crc32(0, rx, sizeof(struct jffs2_raw_xattr) - 4);
 319         if (crc != je32_to_cpu(rx->node_crc)) {
 320                 if (je32_to_cpu(rx->node_crc) != 0xffffffff)
 321                         JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
 322                                       ofs, je32_to_cpu(rx->node_crc), crc);
 323                 DIRTY_SPACE(je32_to_cpu(rx->totlen));
 324                 return 0;
 325         }
 326
 327         totlen = PAD(sizeof(*rx) + rx->name_len + 1 + je16_to_cpu(rx->value_len));
 328         if (totlen != je32_to_cpu(rx->totlen)) {
 329                 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%u\n",
 330                               ofs, je32_to_cpu(rx->totlen), totlen);
 331                 DIRTY_SPACE(je32_to_cpu(rx->totlen));
 332                 return 0;
 333         }
 334
 335         raw =  jffs2_alloc_raw_node_ref();
 336         if (!raw)
 337                 return -ENOMEM;
 338
 339         xd = jffs2_setup_xattr_datum(c, je32_to_cpu(rx->xid), je32_to_cpu(rx->version));
 340         if (IS_ERR(xd)) {
 341                 jffs2_free_raw_node_ref(raw);
 342                 if (PTR_ERR(xd) == -EEXIST) {
 343                         DIRTY_SPACE(PAD(je32_to_cpu(rx->totlen)));
 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         xd->node = raw;
 353
 354         raw->flash_offset = ofs | REF_PRISTINE;
 355         raw->next_in_ino = (void *)xd;
 356
 357         jffs2_link_node_ref(c, jeb, raw, totlen);
 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         struct jffs2_raw_node_ref *raw;
 372         uint32_t crc;
 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                 DIRTY_SPACE(PAD(je32_to_cpu(rr->totlen)));
 380                 return 0;
 381         }
 382
 383         if (PAD(sizeof(struct jffs2_raw_xref)) != je32_to_cpu(rr->totlen)) {
 384                 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%u\n",
 385                               ofs, je32_to_cpu(rr->totlen),
 386                               PAD(sizeof(struct jffs2_raw_xref)));
 387                 DIRTY_SPACE(je32_to_cpu(rr->totlen));
 388                 return 0;
 389         }
 390
 391         ref = jffs2_alloc_xattr_ref();
 392         if (!ref)
 393                 return -ENOMEM;
 394
 395         raw =  jffs2_alloc_raw_node_ref();
 396         if (!raw) {
 397                 jffs2_free_xattr_ref(ref);
 398                 return -ENOMEM;
 399         }
 400
 401         /* BEFORE jffs2_build_xattr_subsystem() called,
 402          * ref->xid is used to store 32bit xid, xd is not used
 403          * ref->ino is used to store 32bit inode-number, ic is not used
 404          * Thoes variables are declared as union, thus using those
 405          * are exclusive. In a similar way, ref->next is temporarily
 406          * used to chain all xattr_ref object. It's re-chained to
 407          * jffs2_inode_cache in jffs2_build_xattr_subsystem() correctly.
 408          */
 409         ref->node = raw;
 410         ref->ino = je32_to_cpu(rr->ino);
 411         ref->xid = je32_to_cpu(rr->xid);
 412         ref->next = c->xref_temp;
 413         c->xref_temp = ref;
 414
 415         raw->flash_offset = ofs | REF_PRISTINE;
 416         raw->next_in_ino = (void *)ref;
 417
 418         jffs2_link_node_ref(c, jeb, raw, PAD(je32_to_cpu(rr->totlen)));
 419
 420         if (jffs2_sum_active())
 421                 jffs2_sum_add_xref_mem(s, rr, ofs - jeb->offset);
 422         dbg_xattr("scan xref at %#08x (xid=%u, ino=%u)\n",
 423                   ofs, ref->xid, ref->ino);
 424         return 0;
 425 }
 426 #endif
 427
 428 /* Called with 'buf_size == 0' if buf is in fact a pointer _directly_ into
 429    the flash, XIP-style */
 430 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 431                                   unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) {
 432         struct jffs2_unknown_node *node;
 433         struct jffs2_unknown_node crcnode;
 434         uint32_t ofs, prevofs;
 435         uint32_t hdr_crc, buf_ofs, buf_len;
 436         int err;
 437         int noise = 0;
 438
 439
 440 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 441         int cleanmarkerfound = 0;
 442 #endif
 443
 444         ofs = jeb->offset;
 445         prevofs = jeb->offset - 1;
 446
 447         D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs));
 448
 449 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 450         if (jffs2_cleanmarker_oob(c)) {
 451                 int ret = jffs2_check_nand_cleanmarker(c, jeb);
 452                 D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n",ret));
 453                 /* Even if it's not found, we still scan to see
 454                    if the block is empty. We use this information
 455                    to decide whether to erase it or not. */
 456                 switch (ret) {
 457                 case 0:         cleanmarkerfound = 1; break;
 458                 case 1:         break;
 459                 case 2:         return BLK_STATE_BADBLOCK;
 460                 case 3:         return BLK_STATE_ALLDIRTY; /* Block has failed to erase min. once */
 461                 default:        return ret;
 462                 }
 463         }
 464 #endif
 465
 466         if (jffs2_sum_active()) {
 467                 struct jffs2_sum_marker *sm;
 468                 void *sumptr = NULL;
 469                 uint32_t sumlen;
 470
 471                 if (!buf_size) {
 472                         /* XIP case. Just look, point at the summary if it's there */
 473                         sm = (void *)buf + jeb->offset - sizeof(*sm);
 474                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
 475                                 sumptr = buf + je32_to_cpu(sm->offset);
 476                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
 477                         }
 478                 } else {
 479                         /* If NAND flash, read a whole page of it. Else just the end */
 480                         if (c->wbuf_pagesize)
 481                                 buf_len = c->wbuf_pagesize;
 482                         else
 483                                 buf_len = sizeof(*sm);
 484
 485                         /* Read as much as we want into the _end_ of the preallocated buffer */
 486                         err = jffs2_fill_scan_buf(c, buf + buf_size - buf_len,
 487                                                   jeb->offset + c->sector_size - buf_len,
 488                                                   buf_len);
 489                         if (err)
 490                                 return err;
 491
 492                         sm = (void *)buf + buf_size - sizeof(*sm);
 493                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
 494                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
 495                                 sumptr = buf + buf_size - sumlen;
 496
 497                                 /* Now, make sure the summary itself is available */
 498                                 if (sumlen > buf_size) {
 499                                         /* Need to kmalloc for this. */
 500                                         sumptr = kmalloc(sumlen, GFP_KERNEL);
 501                                         if (!sumptr)
 502                                                 return -ENOMEM;
 503                                         memcpy(sumptr + sumlen - buf_len, buf + buf_size - buf_len, buf_len);
 504                                 }
 505                                 if (buf_len < sumlen) {
 506                                         /* Need to read more so that the entire summary node is present */
 507                                         err = jffs2_fill_scan_buf(c, sumptr,
 508                                                                   jeb->offset + c->sector_size - sumlen,
 509                                                                   sumlen - buf_len);
 510                                         if (err)
 511                                                 return err;
 512                                 }
 513                         }
 514
 515                 }
 516
 517                 if (sumptr) {
 518                         err = jffs2_sum_scan_sumnode(c, jeb, sumptr, sumlen, &pseudo_random);
 519                         if (err)
 520                                 return err;
 521                         if (buf_size && sumlen > buf_size)
 522                                 kfree(sumptr);
 523                 }
 524         }
 525
 526         buf_ofs = jeb->offset;
 527
 528         if (!buf_size) {
 529                 /* This is the XIP case -- we're reading _directly_ from the flash chip */
 530                 buf_len = c->sector_size;
 531         } else {
 532                 buf_len = EMPTY_SCAN_SIZE(c->sector_size);
 533                 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
 534                 if (err)
 535                         return err;
 536         }
 537
 538         /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
 539         ofs = 0;
 540
 541         /* Scan only 4KiB of 0xFF before declaring it's empty */
 542         while(ofs < EMPTY_SCAN_SIZE(c->sector_size) && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
 543                 ofs += 4;
 544
 545         if (ofs == EMPTY_SCAN_SIZE(c->sector_size)) {
 546 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 547                 if (jffs2_cleanmarker_oob(c)) {
 548                         /* scan oob, take care of cleanmarker */
 549                         int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
 550                         D2(printk(KERN_NOTICE "jffs2_check_oob_empty returned %d\n",ret));
 551                         switch (ret) {
 552                         case 0:         return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
 553                         case 1:         return BLK_STATE_ALLDIRTY;
 554                         default:        return ret;
 555                         }
 556                 }
 557 #endif
 558                 D1(printk(KERN_DEBUG "Block at 0x%08x is empty (erased)\n", jeb->offset));
 559                 if (c->cleanmarker_size == 0)
 560                         return BLK_STATE_CLEANMARKER;   /* don't bother with re-erase */
 561                 else
 562                         return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
 563         }
 564         if (ofs) {
 565                 D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset,
 566                           jeb->offset + ofs));
 567                 DIRTY_SPACE(ofs);
 568         }
 569
 570         /* Now ofs is a complete physical flash offset as it always was... */
 571         ofs += jeb->offset;
 572
 573         noise = 10;
 574
 575         dbg_summary("no summary found in jeb 0x%08x. Apply original scan.\n",jeb->offset);
 576
 577 scan_more:
 578         while(ofs < jeb->offset + c->sector_size) {
 579
 580                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 581
 582                 cond_resched();
 583
 584                 if (ofs & 3) {
 585                         printk(KERN_WARNING "Eep. ofs 0x%08x not word-aligned!\n", ofs);
 586                         ofs = PAD(ofs);
 587                         continue;
 588                 }
 589                 if (ofs == prevofs) {
 590                         printk(KERN_WARNING "ofs 0x%08x has already been seen. Skipping\n", ofs);
 591                         DIRTY_SPACE(4);
 592                         ofs += 4;
 593                         continue;
 594                 }
 595                 prevofs = ofs;
 596
 597                 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
 598                         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),
 599                                   jeb->offset, c->sector_size, ofs, sizeof(*node)));
 600                         DIRTY_SPACE((jeb->offset + c->sector_size)-ofs);
 601                         break;
 602                 }
 603
 604                 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
 605                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 606                         D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
 607                                   sizeof(struct jffs2_unknown_node), buf_len, ofs));
 608                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 609                         if (err)
 610                                 return err;
 611                         buf_ofs = ofs;
 612                 }
 613
 614                 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
 615
 616                 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
 617                         uint32_t inbuf_ofs;
 618                         uint32_t empty_start;
 619
 620                         empty_start = ofs;
 621                         ofs += 4;
 622
 623                         D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs));
 624                 more_empty:
 625                         inbuf_ofs = ofs - buf_ofs;
 626                         while (inbuf_ofs < buf_len) {
 627                                 if (*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff) {
 628                                         printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n",
 629                                                empty_start, ofs);
 630                                         DIRTY_SPACE(ofs-empty_start);
 631                                         goto scan_more;
 632                                 }
 633
 634                                 inbuf_ofs+=4;
 635                                 ofs += 4;
 636                         }
 637                         /* Ran off end. */
 638                         D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs));
 639
 640                         /* If we're only checking the beginning of a block with a cleanmarker,
 641                            bail now */
 642                         if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&
 643                             c->cleanmarker_size && !jeb->dirty_size && !jeb->first_node->next_phys) {
 644                                 D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE(c->sector_size)));
 645                                 return BLK_STATE_CLEANMARKER;
 646                         }
 647
 648                         /* See how much more there is to read in this eraseblock... */
 649                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 650                         if (!buf_len) {
 651                                 /* No more to read. Break out of main loop without marking
 652                                    this range of empty space as dirty (because it's not) */
 653                                 D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block. Treating as free_space\n",
 654                                           empty_start));
 655                                 break;
 656                         }
 657                         D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs));
 658                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 659                         if (err)
 660                                 return err;
 661                         buf_ofs = ofs;
 662                         goto more_empty;
 663                 }
 664
 665                 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
 666                         printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n", ofs);
 667                         DIRTY_SPACE(4);
 668                         ofs += 4;
 669                         continue;
 670                 }
 671                 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
 672                         D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs));
 673                         DIRTY_SPACE(4);
 674                         ofs += 4;
 675                         continue;
 676                 }
 677                 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
 678                         printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08x\n", ofs);
 679                         printk(KERN_WARNING "You cannot use older JFFS2 filesystems with newer kernels\n");
 680                         DIRTY_SPACE(4);
 681                         ofs += 4;
 682                         continue;
 683                 }
 684                 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
 685                         /* OK. We're out of possibilities. Whinge and move on */
 686                         noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n",
 687                                      JFFS2_MAGIC_BITMASK, ofs,
 688                                      je16_to_cpu(node->magic));
 689                         DIRTY_SPACE(4);
 690                         ofs += 4;
 691                         continue;
 692                 }
 693                 /* We seem to have a node of sorts. Check the CRC */
 694                 crcnode.magic = node->magic;
 695                 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
 696                 crcnode.totlen = node->totlen;
 697                 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
 698
 699                 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
 700                         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",
 701                                      ofs, je16_to_cpu(node->magic),
 702                                      je16_to_cpu(node->nodetype),
 703                                      je32_to_cpu(node->totlen),
 704                                      je32_to_cpu(node->hdr_crc),
 705                                      hdr_crc);
 706                         DIRTY_SPACE(4);
 707                         ofs += 4;
 708                         continue;
 709                 }
 710
 711                 if (ofs + je32_to_cpu(node->totlen) >
 712                     jeb->offset + c->sector_size) {
 713                         /* Eep. Node goes over the end of the erase block. */
 714                         printk(KERN_WARNING "Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
 715                                ofs, je32_to_cpu(node->totlen));
 716                         printk(KERN_WARNING "Perhaps the file system was created with the wrong erase size?\n");
 717                         DIRTY_SPACE(4);
 718                         ofs += 4;
 719                         continue;
 720                 }
 721
 722                 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
 723                         /* Wheee. This is an obsoleted node */
 724                         D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs));
 725                         DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 726                         ofs += PAD(je32_to_cpu(node->totlen));
 727                         continue;
 728                 }
 729
 730                 switch(je16_to_cpu(node->nodetype)) {
 731                 case JFFS2_NODETYPE_INODE:
 732                         if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
 733                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 734                                 D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
 735                                           sizeof(struct jffs2_raw_inode), buf_len, ofs));
 736                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 737                                 if (err)
 738                                         return err;
 739                                 buf_ofs = ofs;
 740                                 node = (void *)buf;
 741                         }
 742                         err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs, s);
 743                         if (err) return err;
 744                         ofs += PAD(je32_to_cpu(node->totlen));
 745                         break;
 746
 747                 case JFFS2_NODETYPE_DIRENT:
 748                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 749                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 750                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
 751                                           je32_to_cpu(node->totlen), 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_dirent_node(c, jeb, (void *)node, ofs, s);
 759                         if (err) return err;
 760                         ofs += PAD(je32_to_cpu(node->totlen));
 761                         break;
 762
 763 #ifdef CONFIG_JFFS2_FS_XATTR
 764                 case JFFS2_NODETYPE_XATTR:
 765                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 766                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 767                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (xattr node)"
 768                                           " left to end of buf. Reading 0x%x at 0x%08x\n",
 769                                           je32_to_cpu(node->totlen), buf_len, ofs));
 770                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 771                                 if (err)
 772                                         return err;
 773                                 buf_ofs = ofs;
 774                                 node = (void *)buf;
 775                         }
 776                         err = jffs2_scan_xattr_node(c, jeb, (void *)node, ofs, s);
 777                         if (err)
 778                                 return err;
 779                         ofs += PAD(je32_to_cpu(node->totlen));
 780                         break;
 781                 case JFFS2_NODETYPE_XREF:
 782                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 783                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 784                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (xref node)"
 785                                           " left to end of buf. Reading 0x%x at 0x%08x\n",
 786                                           je32_to_cpu(node->totlen), buf_len, ofs));
 787                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 788                                 if (err)
 789                                         return err;
 790                                 buf_ofs = ofs;
 791                                 node = (void *)buf;
 792                         }
 793                         err = jffs2_scan_xref_node(c, jeb, (void *)node, ofs, s);
 794                         if (err)
 795                                 return err;
 796                         ofs += PAD(je32_to_cpu(node->totlen));
 797                         break;
 798 #endif  /* CONFIG_JFFS2_FS_XATTR */
 799
 800                 case JFFS2_NODETYPE_CLEANMARKER:
 801                         D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs));
 802                         if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
 803                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n",
 804                                        ofs, je32_to_cpu(node->totlen), c->cleanmarker_size);
 805                                 DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
 806                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 807                         } else if (jeb->first_node) {
 808                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n", ofs, jeb->offset);
 809                                 DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
 810                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 811                         } else {
 812                                 struct jffs2_raw_node_ref *marker_ref = jffs2_alloc_raw_node_ref();
 813                                 if (!marker_ref) {
 814                                         printk(KERN_NOTICE "Failed to allocate node ref for clean marker\n");
 815                                         return -ENOMEM;
 816                                 }
 817                                 marker_ref->next_in_ino = NULL;
 818                                 marker_ref->flash_offset = ofs | REF_NORMAL;
 819
 820                                 jffs2_link_node_ref(c, jeb, marker_ref, c->cleanmarker_size);
 821
 822                                 ofs += PAD(c->cleanmarker_size);
 823                         }
 824                         break;
 825
 826                 case JFFS2_NODETYPE_PADDING:
 827                         if (jffs2_sum_active())
 828                                 jffs2_sum_add_padding_mem(s, je32_to_cpu(node->totlen));
 829                         DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 830                         ofs += PAD(je32_to_cpu(node->totlen));
 831                         break;
 832
 833                 default:
 834                         switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
 835                         case JFFS2_FEATURE_ROCOMPAT:
 836                                 printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 837                                 c->flags |= JFFS2_SB_FLAG_RO;
 838                                 if (!(jffs2_is_readonly(c)))
 839                                         return -EROFS;
 840                                 DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 841                                 ofs += PAD(je32_to_cpu(node->totlen));
 842                                 break;
 843
 844                         case JFFS2_FEATURE_INCOMPAT:
 845                                 printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 846                                 return -EINVAL;
 847
 848                         case JFFS2_FEATURE_RWCOMPAT_DELETE:
 849                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 850                                 DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 851                                 ofs += PAD(je32_to_cpu(node->totlen));
 852                                 break;
 853
 854                         case JFFS2_FEATURE_RWCOMPAT_COPY:
 855                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 856                                 USED_SPACE(PAD(je32_to_cpu(node->totlen)));
 857                                 ofs += PAD(je32_to_cpu(node->totlen));
 858                                 break;
 859                         }
 860                 }
 861         }
 862
 863         if (jffs2_sum_active()) {
 864                 if (PAD(s->sum_size + JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size) {
 865                         dbg_summary("There is not enough space for "
 866                                 "summary information, disabling for this jeb!\n");
 867                         jffs2_sum_disable_collecting(s);
 868                 }
 869         }
 870
 871         D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x\n", jeb->offset,
 872                   jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size));
 873
 874         /* mark_node_obsolete can add to wasted !! */
 875         if (jeb->wasted_size) {
 876                 jeb->dirty_size += jeb->wasted_size;
 877                 c->dirty_size += jeb->wasted_size;
 878                 c->wasted_size -= jeb->wasted_size;
 879                 jeb->wasted_size = 0;
 880         }
 881
 882         return jffs2_scan_classify_jeb(c, jeb);
 883 }
 884
 885 struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
 886 {
 887         struct jffs2_inode_cache *ic;
 888
 889         ic = jffs2_get_ino_cache(c, ino);
 890         if (ic)
 891                 return ic;
 892
 893         if (ino > c->highest_ino)
 894                 c->highest_ino = ino;
 895
 896         ic = jffs2_alloc_inode_cache();
 897         if (!ic) {
 898                 printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n");
 899                 return NULL;
 900         }
 901         memset(ic, 0, sizeof(*ic));
 902
 903         ic->ino = ino;
 904         ic->nodes = (void *)ic;
 905         jffs2_add_ino_cache(c, ic);
 906         if (ino == 1)
 907                 ic->nlink = 1;
 908         return ic;
 909 }
 910
 911 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 912                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s)
 913 {
 914         struct jffs2_raw_node_ref *raw;
 915         struct jffs2_inode_cache *ic;
 916         uint32_t ino = je32_to_cpu(ri->ino);
 917
 918         D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs));
 919
 920         /* We do very little here now. Just check the ino# to which we should attribute
 921            this node; we can do all the CRC checking etc. later. There's a tradeoff here --
 922            we used to scan the flash once only, reading everything we want from it into
 923            memory, then building all our in-core data structures and freeing the extra
 924            information. Now we allow the first part of the mount to complete a lot quicker,
 925            but we have to go _back_ to the flash in order to finish the CRC checking, etc.
 926            Which means that the _full_ amount of time to get to proper write mode with GC
 927            operational may actually be _longer_ than before. Sucks to be me. */
 928
 929         raw = jffs2_alloc_raw_node_ref();
 930         if (!raw) {
 931                 printk(KERN_NOTICE "jffs2_scan_inode_node(): allocation of node reference failed\n");
 932                 return -ENOMEM;
 933         }
 934
 935         ic = jffs2_get_ino_cache(c, ino);
 936         if (!ic) {
 937                 /* Inocache get failed. Either we read a bogus ino# or it's just genuinely the
 938                    first node we found for this inode. Do a CRC check to protect against the former
 939                    case */
 940                 uint32_t crc = crc32(0, ri, sizeof(*ri)-8);
 941
 942                 if (crc != je32_to_cpu(ri->node_crc)) {
 943                         printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 944                                ofs, je32_to_cpu(ri->node_crc), crc);
 945                         /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
 946                         DIRTY_SPACE(PAD(je32_to_cpu(ri->totlen)));
 947                         jffs2_free_raw_node_ref(raw);
 948                         return 0;
 949                 }
 950                 ic = jffs2_scan_make_ino_cache(c, ino);
 951                 if (!ic) {
 952                         jffs2_free_raw_node_ref(raw);
 953                         return -ENOMEM;
 954                 }
 955         }
 956
 957         /* Wheee. It worked */
 958
 959         raw->flash_offset = ofs | REF_UNCHECKED;
 960
 961         raw->next_in_ino = ic->nodes;
 962         ic->nodes = raw;
 963
 964         jffs2_link_node_ref(c, jeb, raw, PAD(je32_to_cpu(ri->totlen)));
 965
 966         D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
 967                   je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
 968                   je32_to_cpu(ri->offset),
 969                   je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize)));
 970
 971         pseudo_random += je32_to_cpu(ri->version);
 972
 973         if (jffs2_sum_active()) {
 974                 jffs2_sum_add_inode_mem(s, ri, ofs - jeb->offset);
 975         }
 976
 977         return 0;
 978 }
 979
 980 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 981                                   struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s)
 982 {
 983         struct jffs2_raw_node_ref *raw;
 984         struct jffs2_full_dirent *fd;
 985         struct jffs2_inode_cache *ic;
 986         uint32_t crc;
 987
 988         D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs));
 989
 990         /* We don't get here unless the node is still valid, so we don't have to
 991            mask in the ACCURATE bit any more. */
 992         crc = crc32(0, rd, sizeof(*rd)-8);
 993
 994         if (crc != je32_to_cpu(rd->node_crc)) {
 995                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 996                        ofs, je32_to_cpu(rd->node_crc), crc);
 997                 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
 998                 DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
 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                 DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
1020                 return 0;
1021         }
1022         raw = jffs2_alloc_raw_node_ref();
1023         if (!raw) {
1024                 jffs2_free_full_dirent(fd);
1025                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): allocation of node reference failed\n");
1026                 return -ENOMEM;
1027         }
1028         ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
1029         if (!ic) {
1030                 jffs2_free_full_dirent(fd);
1031                 jffs2_free_raw_node_ref(raw);
1032                 return -ENOMEM;
1033         }
1034
1035         raw->flash_offset = ofs | REF_PRISTINE;
1036         raw->next_in_ino = ic->nodes;
1037         ic->nodes = raw;
1038
1039         jffs2_link_node_ref(c, jeb, raw, PAD(je32_to_cpu(rd->totlen)));
1040
1041         fd->raw = raw;
1042         fd->next = NULL;
1043         fd->version = je32_to_cpu(rd->version);
1044         fd->ino = je32_to_cpu(rd->ino);
1045         fd->nhash = full_name_hash(fd->name, rd->nsize);
1046         fd->type = rd->type;
1047         jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
1048
1049         if (jffs2_sum_active()) {
1050                 jffs2_sum_add_dirent_mem(s, rd, ofs - jeb->offset);
1051         }
1052
1053         return 0;
1054 }
1055
1056 static int count_list(struct list_head *l)
1057 {
1058         uint32_t count = 0;
1059         struct list_head *tmp;
1060
1061         list_for_each(tmp, l) {
1062                 count++;
1063         }
1064         return count;
1065 }
1066
1067 /* Note: This breaks if list_empty(head). I don't care. You
1068    might, if you copy this code and use it elsewhere :) */
1069 static void rotate_list(struct list_head *head, uint32_t count)
1070 {
1071         struct list_head *n = head->next;
1072
1073         list_del(head);
1074         while(count--) {
1075                 n = n->next;
1076         }
1077         list_add(head, n);
1078 }
1079
1080 void jffs2_rotate_lists(struct jffs2_sb_info *c)
1081 {
1082         uint32_t x;
1083         uint32_t rotateby;
1084
1085         x = count_list(&c->clean_list);
1086         if (x) {
1087                 rotateby = pseudo_random % x;
1088                 rotate_list((&c->clean_list), rotateby);
1089         }
1090
1091         x = count_list(&c->very_dirty_list);
1092         if (x) {
1093                 rotateby = pseudo_random % x;
1094                 rotate_list((&c->very_dirty_list), rotateby);
1095         }
1096
1097         x = count_list(&c->dirty_list);
1098         if (x) {
1099                 rotateby = pseudo_random % x;
1100                 rotate_list((&c->dirty_list), rotateby);
1101         }
1102
1103         x = count_list(&c->erasable_list);
1104         if (x) {
1105                 rotateby = pseudo_random % x;
1106                 rotate_list((&c->erasable_list), rotateby);
1107         }
1108
1109         if (c->nr_erasing_blocks) {
1110                 rotateby = pseudo_random % c->nr_erasing_blocks;
1111                 rotate_list((&c->erase_pending_list), rotateby);
1112         }
1113
1114         if (c->nr_free_blocks) {
1115                 rotateby = pseudo_random % c->nr_free_blocks;
1116                 rotate_list((&c->free_list), rotateby);
1117         }
1118 }