git.oblomov.eu Git - linux-2.6/blob - fs/jffs2/scan.c

   1 /*
   2  * JFFS2 -- Journalling Flash File System, Version 2.
   3  *
   4  * Copyright © 2001-2007 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  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/sched.h>
  14 #include <linux/slab.h>
  15 #include <linux/mtd/mtd.h>
  16 #include <linux/pagemap.h>
  17 #include <linux/crc32.h>
  18 #include <linux/compiler.h>
  19 #include "nodelist.h"
  20 #include "summary.h"
  21 #include "debug.h"
  22
  23 #define DEFAULT_EMPTY_SCAN_SIZE 1024
  24
  25 #define noisy_printk(noise, args...) do { \
  26         if (*(noise)) { \
  27                 printk(KERN_NOTICE args); \
  28                  (*(noise))--; \
  29                  if (!(*(noise))) { \
  30                          printk(KERN_NOTICE "Further such events for this erase block will not be printed\n"); \
  31                  } \
  32         } \
  33 } while(0)
  34
  35 static uint32_t pseudo_random;
  36
  37 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  38                                   unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s);
  39
  40 /* These helper functions _must_ increase ofs and also do the dirty/used space accounting.
  41  * Returning an error will abort the mount - bad checksums etc. should just mark the space
  42  * as dirty.
  43  */
  44 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  45                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s);
  46 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  47                                  struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s);
  48
  49 static inline int min_free(struct jffs2_sb_info *c)
  50 {
  51         uint32_t min = 2 * sizeof(struct jffs2_raw_inode);
  52 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
  53         if (!jffs2_can_mark_obsolete(c) && min < c->wbuf_pagesize)
  54                 return c->wbuf_pagesize;
  55 #endif
  56         return min;
  57
  58 }
  59
  60 static inline uint32_t EMPTY_SCAN_SIZE(uint32_t sector_size) {
  61         if (sector_size < DEFAULT_EMPTY_SCAN_SIZE)
  62                 return sector_size;
  63         else
  64                 return DEFAULT_EMPTY_SCAN_SIZE;
  65 }
  66
  67 static int file_dirty(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
  68 {
  69         int ret;
  70
  71         if ((ret = jffs2_prealloc_raw_node_refs(c, jeb, 1)))
  72                 return ret;
  73         if ((ret = jffs2_scan_dirty_space(c, jeb, jeb->free_size)))
  74                 return ret;
  75         /* Turned wasted size into dirty, since we apparently
  76            think it's recoverable now. */
  77         jeb->dirty_size += jeb->wasted_size;
  78         c->dirty_size += jeb->wasted_size;
  79         c->wasted_size -= jeb->wasted_size;
  80         jeb->wasted_size = 0;
  81         if (VERYDIRTY(c, jeb->dirty_size)) {
  82                 list_add(&jeb->list, &c->very_dirty_list);
  83         } else {
  84                 list_add(&jeb->list, &c->dirty_list);
  85         }
  86         return 0;
  87 }
  88
  89 int jffs2_scan_medium(struct jffs2_sb_info *c)
  90 {
  91         int i, ret;
  92         uint32_t empty_blocks = 0, bad_blocks = 0;
  93         unsigned char *flashbuf = NULL;
  94         uint32_t buf_size = 0;
  95         struct jffs2_summary *s = NULL; /* summary info collected by the scan process */
  96 #ifndef __ECOS
  97         size_t pointlen;
  98
  99         if (c->mtd->point) {
 100                 ret = c->mtd->point (c->mtd, 0, c->mtd->size, &pointlen, &flashbuf);
 101                 if (!ret && pointlen < c->mtd->size) {
 102                         /* Don't muck about if it won't let us point to the whole flash */
 103                         D1(printk(KERN_DEBUG "MTD point returned len too short: 0x%zx\n", pointlen));
 104                         c->mtd->unpoint(c->mtd, flashbuf, 0, pointlen);
 105                         flashbuf = NULL;
 106                 }
 107                 if (ret)
 108                         D1(printk(KERN_DEBUG "MTD point failed %d\n", ret));
 109         }
 110 #endif
 111         if (!flashbuf) {
 112                 /* For NAND it's quicker to read a whole eraseblock at a time,
 113                    apparently */
 114                 if (jffs2_cleanmarker_oob(c))
 115                         buf_size = c->sector_size;
 116                 else
 117                         buf_size = PAGE_SIZE;
 118
 119                 /* Respect kmalloc limitations */
 120                 if (buf_size > 128*1024)
 121                         buf_size = 128*1024;
 122
 123                 D1(printk(KERN_DEBUG "Allocating readbuf of %d bytes\n", buf_size));
 124                 flashbuf = kmalloc(buf_size, GFP_KERNEL);
 125                 if (!flashbuf)
 126                         return -ENOMEM;
 127         }
 128
 129         if (jffs2_sum_active()) {
 130                 s = kzalloc(sizeof(struct jffs2_summary), GFP_KERNEL);
 131                 if (!s) {
 132                         kfree(flashbuf);
 133                         JFFS2_WARNING("Can't allocate memory for summary\n");
 134                         return -ENOMEM;
 135                 }
 136         }
 137
 138         for (i=0; i<c->nr_blocks; i++) {
 139                 struct jffs2_eraseblock *jeb = &c->blocks[i];
 140
 141                 cond_resched();
 142
 143                 /* reset summary info for next eraseblock scan */
 144                 jffs2_sum_reset_collected(s);
 145
 146                 ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset),
 147                                                 buf_size, s);
 148
 149                 if (ret < 0)
 150                         goto out;
 151
 152                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 153
 154                 /* Now decide which list to put it on */
 155                 switch(ret) {
 156                 case BLK_STATE_ALLFF:
 157                         /*
 158                          * Empty block.   Since we can't be sure it
 159                          * was entirely erased, we just queue it for erase
 160                          * again.  It will be marked as such when the erase
 161                          * is complete.  Meanwhile we still count it as empty
 162                          * for later checks.
 163                          */
 164                         empty_blocks++;
 165                         list_add(&jeb->list, &c->erase_pending_list);
 166                         c->nr_erasing_blocks++;
 167                         break;
 168
 169                 case BLK_STATE_CLEANMARKER:
 170                         /* Only a CLEANMARKER node is valid */
 171                         if (!jeb->dirty_size) {
 172                                 /* It's actually free */
 173                                 list_add(&jeb->list, &c->free_list);
 174                                 c->nr_free_blocks++;
 175                         } else {
 176                                 /* Dirt */
 177                                 D1(printk(KERN_DEBUG "Adding all-dirty block at 0x%08x to erase_pending_list\n", jeb->offset));
 178                                 list_add(&jeb->list, &c->erase_pending_list);
 179                                 c->nr_erasing_blocks++;
 180                         }
 181                         break;
 182
 183                 case BLK_STATE_CLEAN:
 184                         /* Full (or almost full) of clean data. Clean list */
 185                         list_add(&jeb->list, &c->clean_list);
 186                         break;
 187
 188                 case BLK_STATE_PARTDIRTY:
 189                         /* Some data, but not full. Dirty list. */
 190                         /* We want to remember the block with most free space
 191                         and stick it in the 'nextblock' position to start writing to it. */
 192                         if (jeb->free_size > min_free(c) &&
 193                                         (!c->nextblock || c->nextblock->free_size < jeb->free_size)) {
 194                                 /* Better candidate for the next writes to go to */
 195                                 if (c->nextblock) {
 196                                         ret = file_dirty(c, c->nextblock);
 197                                         if (ret)
 198                                                 return ret;
 199                                         /* deleting summary information of the old nextblock */
 200                                         jffs2_sum_reset_collected(c->summary);
 201                                 }
 202                                 /* update collected summary information for the current nextblock */
 203                                 jffs2_sum_move_collected(c, s);
 204                                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): new nextblock = 0x%08x\n", jeb->offset));
 205                                 c->nextblock = jeb;
 206                         } else {
 207                                 ret = file_dirty(c, jeb);
 208                                 if (ret)
 209                                         return ret;
 210                         }
 211                         break;
 212
 213                 case BLK_STATE_ALLDIRTY:
 214                         /* Nothing valid - not even a clean marker. Needs erasing. */
 215                         /* For now we just put it on the erasing list. We'll start the erases later */
 216                         D1(printk(KERN_NOTICE "JFFS2: Erase block at 0x%08x is not formatted. It will be erased\n", jeb->offset));
 217                         list_add(&jeb->list, &c->erase_pending_list);
 218                         c->nr_erasing_blocks++;
 219                         break;
 220
 221                 case BLK_STATE_BADBLOCK:
 222                         D1(printk(KERN_NOTICE "JFFS2: Block at 0x%08x is bad\n", jeb->offset));
 223                         list_add(&jeb->list, &c->bad_list);
 224                         c->bad_size += c->sector_size;
 225                         c->free_size -= c->sector_size;
 226                         bad_blocks++;
 227                         break;
 228                 default:
 229                         printk(KERN_WARNING "jffs2_scan_medium(): unknown block state\n");
 230                         BUG();
 231                 }
 232         }
 233
 234         /* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
 235         if (c->nextblock && (c->nextblock->dirty_size)) {
 236                 c->nextblock->wasted_size += c->nextblock->dirty_size;
 237                 c->wasted_size += c->nextblock->dirty_size;
 238                 c->dirty_size -= c->nextblock->dirty_size;
 239                 c->nextblock->dirty_size = 0;
 240         }
 241 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 242         if (!jffs2_can_mark_obsolete(c) && c->wbuf_pagesize && c->nextblock && (c->nextblock->free_size % c->wbuf_pagesize)) {
 243                 /* If we're going to start writing into a block which already
 244                    contains data, and the end of the data isn't page-aligned,
 245                    skip a little and align it. */
 246
 247                 uint32_t skip = c->nextblock->free_size % c->wbuf_pagesize;
 248
 249                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): Skipping %d bytes in nextblock to ensure page alignment\n",
 250                           skip));
 251                 jffs2_prealloc_raw_node_refs(c, c->nextblock, 1);
 252                 jffs2_scan_dirty_space(c, c->nextblock, skip);
 253         }
 254 #endif
 255         if (c->nr_erasing_blocks) {
 256                 if ( !c->used_size && ((c->nr_free_blocks+empty_blocks+bad_blocks)!= c->nr_blocks || bad_blocks == c->nr_blocks) ) {
 257                         printk(KERN_NOTICE "Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
 258                         printk(KERN_NOTICE "empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",empty_blocks,bad_blocks,c->nr_blocks);
 259                         ret = -EIO;
 260                         goto out;
 261                 }
 262                 jffs2_erase_pending_trigger(c);
 263         }
 264         ret = 0;
 265  out:
 266         if (buf_size)
 267                 kfree(flashbuf);
 268 #ifndef __ECOS
 269         else
 270                 c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
 271 #endif
 272         if (s)
 273                 kfree(s);
 274
 275         return ret;
 276 }
 277
 278 static int jffs2_fill_scan_buf(struct jffs2_sb_info *c, void *buf,
 279                                uint32_t ofs, uint32_t len)
 280 {
 281         int ret;
 282         size_t retlen;
 283
 284         ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
 285         if (ret) {
 286                 D1(printk(KERN_WARNING "mtd->read(0x%x bytes from 0x%x) returned %d\n", len, ofs, ret));
 287                 return ret;
 288         }
 289         if (retlen < len) {
 290                 D1(printk(KERN_WARNING "Read at 0x%x gave only 0x%zx bytes\n", ofs, retlen));
 291                 return -EIO;
 292         }
 293         return 0;
 294 }
 295
 296 int jffs2_scan_classify_jeb(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
 297 {
 298         if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size
 299             && (!jeb->first_node || !ref_next(jeb->first_node)) )
 300                 return BLK_STATE_CLEANMARKER;
 301
 302         /* move blocks with max 4 byte dirty space to cleanlist */
 303         else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
 304                 c->dirty_size -= jeb->dirty_size;
 305                 c->wasted_size += jeb->dirty_size;
 306                 jeb->wasted_size += jeb->dirty_size;
 307                 jeb->dirty_size = 0;
 308                 return BLK_STATE_CLEAN;
 309         } else if (jeb->used_size || jeb->unchecked_size)
 310                 return BLK_STATE_PARTDIRTY;
 311         else
 312                 return BLK_STATE_ALLDIRTY;
 313 }
 314
 315 #ifdef CONFIG_JFFS2_FS_XATTR
 316 static int jffs2_scan_xattr_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 317                                  struct jffs2_raw_xattr *rx, uint32_t ofs,
 318                                  struct jffs2_summary *s)
 319 {
 320         struct jffs2_xattr_datum *xd;
 321         uint32_t xid, version, totlen, crc;
 322         int err;
 323
 324         crc = crc32(0, rx, sizeof(struct jffs2_raw_xattr) - 4);
 325         if (crc != je32_to_cpu(rx->node_crc)) {
 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         xid = je32_to_cpu(rx->xid);
 334         version = je32_to_cpu(rx->version);
 335
 336         totlen = PAD(sizeof(struct jffs2_raw_xattr)
 337                         + rx->name_len + 1 + je16_to_cpu(rx->value_len));
 338         if (totlen != je32_to_cpu(rx->totlen)) {
 339                 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%u\n",
 340                               ofs, je32_to_cpu(rx->totlen), totlen);
 341                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
 342                         return err;
 343                 return 0;
 344         }
 345
 346         xd = jffs2_setup_xattr_datum(c, xid, version);
 347         if (IS_ERR(xd))
 348                 return PTR_ERR(xd);
 349
 350         if (xd->version > version) {
 351                 struct jffs2_raw_node_ref *raw
 352                         = jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, NULL);
 353                 raw->next_in_ino = xd->node->next_in_ino;
 354                 xd->node->next_in_ino = raw;
 355         } else {
 356                 xd->version = version;
 357                 xd->xprefix = rx->xprefix;
 358                 xd->name_len = rx->name_len;
 359                 xd->value_len = je16_to_cpu(rx->value_len);
 360                 xd->data_crc = je32_to_cpu(rx->data_crc);
 361
 362                 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, (void *)xd);
 363         }
 364
 365         if (jffs2_sum_active())
 366                 jffs2_sum_add_xattr_mem(s, rx, ofs - jeb->offset);
 367         dbg_xattr("scaning xdatum at %#08x (xid=%u, version=%u)\n",
 368                   ofs, xd->xid, xd->version);
 369         return 0;
 370 }
 371
 372 static int jffs2_scan_xref_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 373                                 struct jffs2_raw_xref *rr, uint32_t ofs,
 374                                 struct jffs2_summary *s)
 375 {
 376         struct jffs2_xattr_ref *ref;
 377         uint32_t crc;
 378         int err;
 379
 380         crc = crc32(0, rr, sizeof(*rr) - 4);
 381         if (crc != je32_to_cpu(rr->node_crc)) {
 382                 JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
 383                               ofs, je32_to_cpu(rr->node_crc), crc);
 384                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rr->totlen)))))
 385                         return err;
 386                 return 0;
 387         }
 388
 389         if (PAD(sizeof(struct jffs2_raw_xref)) != je32_to_cpu(rr->totlen)) {
 390                 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%zd\n",
 391                               ofs, je32_to_cpu(rr->totlen),
 392                               PAD(sizeof(struct jffs2_raw_xref)));
 393                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rr->totlen))))
 394                         return err;
 395                 return 0;
 396         }
 397
 398         ref = jffs2_alloc_xattr_ref();
 399         if (!ref)
 400                 return -ENOMEM;
 401
 402         /* BEFORE jffs2_build_xattr_subsystem() called,
 403          * and AFTER xattr_ref is marked as a dead xref,
 404          * ref->xid is used to store 32bit xid, xd is not used
 405          * ref->ino is used to store 32bit inode-number, ic is not used
 406          * Thoes variables are declared as union, thus using those
 407          * are exclusive. In a similar way, ref->next is temporarily
 408          * used to chain all xattr_ref object. It's re-chained to
 409          * jffs2_inode_cache in jffs2_build_xattr_subsystem() correctly.
 410          */
 411         ref->ino = je32_to_cpu(rr->ino);
 412         ref->xid = je32_to_cpu(rr->xid);
 413         ref->xseqno = je32_to_cpu(rr->xseqno);
 414         if (ref->xseqno > c->highest_xseqno)
 415                 c->highest_xseqno = (ref->xseqno & ~XREF_DELETE_MARKER);
 416         ref->next = c->xref_temp;
 417         c->xref_temp = ref;
 418
 419         jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(rr->totlen)), (void *)ref);
 420
 421         if (jffs2_sum_active())
 422                 jffs2_sum_add_xref_mem(s, rr, ofs - jeb->offset);
 423         dbg_xattr("scan xref at %#08x (xid=%u, ino=%u)\n",
 424                   ofs, ref->xid, ref->ino);
 425         return 0;
 426 }
 427 #endif
 428
 429 /* Called with 'buf_size == 0' if buf is in fact a pointer _directly_ into
 430    the flash, XIP-style */
 431 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 432                                   unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) {
 433         struct jffs2_unknown_node *node;
 434         struct jffs2_unknown_node crcnode;
 435         uint32_t ofs, prevofs;
 436         uint32_t hdr_crc, buf_ofs, buf_len;
 437         int err;
 438         int noise = 0;
 439
 440
 441 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 442         int cleanmarkerfound = 0;
 443 #endif
 444
 445         ofs = jeb->offset;
 446         prevofs = jeb->offset - 1;
 447
 448         D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs));
 449
 450 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 451         if (jffs2_cleanmarker_oob(c)) {
 452                 int ret;
 453
 454                 if (c->mtd->block_isbad(c->mtd, jeb->offset))
 455                         return BLK_STATE_BADBLOCK;
 456
 457                 ret = jffs2_check_nand_cleanmarker(c, jeb);
 458                 D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n",ret));
 459
 460                 /* Even if it's not found, we still scan to see
 461                    if the block is empty. We use this information
 462                    to decide whether to erase it or not. */
 463                 switch (ret) {
 464                 case 0:         cleanmarkerfound = 1; break;
 465                 case 1:         break;
 466                 default:        return ret;
 467                 }
 468         }
 469 #endif
 470
 471         if (jffs2_sum_active()) {
 472                 struct jffs2_sum_marker *sm;
 473                 void *sumptr = NULL;
 474                 uint32_t sumlen;
 475
 476                 if (!buf_size) {
 477                         /* XIP case. Just look, point at the summary if it's there */
 478                         sm = (void *)buf + c->sector_size - sizeof(*sm);
 479                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
 480                                 sumptr = buf + je32_to_cpu(sm->offset);
 481                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
 482                         }
 483                 } else {
 484                         /* If NAND flash, read a whole page of it. Else just the end */
 485                         if (c->wbuf_pagesize)
 486                                 buf_len = c->wbuf_pagesize;
 487                         else
 488                                 buf_len = sizeof(*sm);
 489
 490                         /* Read as much as we want into the _end_ of the preallocated buffer */
 491                         err = jffs2_fill_scan_buf(c, buf + buf_size - buf_len,
 492                                                   jeb->offset + c->sector_size - buf_len,
 493                                                   buf_len);
 494                         if (err)
 495                                 return err;
 496
 497                         sm = (void *)buf + buf_size - sizeof(*sm);
 498                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
 499                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
 500                                 sumptr = buf + buf_size - sumlen;
 501
 502                                 /* Now, make sure the summary itself is available */
 503                                 if (sumlen > buf_size) {
 504                                         /* Need to kmalloc for this. */
 505                                         sumptr = kmalloc(sumlen, GFP_KERNEL);
 506                                         if (!sumptr)
 507                                                 return -ENOMEM;
 508                                         memcpy(sumptr + sumlen - buf_len, buf + buf_size - buf_len, buf_len);
 509                                 }
 510                                 if (buf_len < sumlen) {
 511                                         /* Need to read more so that the entire summary node is present */
 512                                         err = jffs2_fill_scan_buf(c, sumptr,
 513                                                                   jeb->offset + c->sector_size - sumlen,
 514                                                                   sumlen - buf_len);
 515                                         if (err)
 516                                                 return err;
 517                                 }
 518                         }
 519
 520                 }
 521
 522                 if (sumptr) {
 523                         err = jffs2_sum_scan_sumnode(c, jeb, sumptr, sumlen, &pseudo_random);
 524
 525                         if (buf_size && sumlen > buf_size)
 526                                 kfree(sumptr);
 527                         /* If it returns with a real error, bail.
 528                            If it returns positive, that's a block classification
 529                            (i.e. BLK_STATE_xxx) so return that too.
 530                            If it returns zero, fall through to full scan. */
 531                         if (err)
 532                                 return err;
 533                 }
 534         }
 535
 536         buf_ofs = jeb->offset;
 537
 538         if (!buf_size) {
 539                 /* This is the XIP case -- we're reading _directly_ from the flash chip */
 540                 buf_len = c->sector_size;
 541         } else {
 542                 buf_len = EMPTY_SCAN_SIZE(c->sector_size);
 543                 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
 544                 if (err)
 545                         return err;
 546         }
 547
 548         /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
 549         ofs = 0;
 550
 551         /* Scan only 4KiB of 0xFF before declaring it's empty */
 552         while(ofs < EMPTY_SCAN_SIZE(c->sector_size) && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
 553                 ofs += 4;
 554
 555         if (ofs == EMPTY_SCAN_SIZE(c->sector_size)) {
 556 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 557                 if (jffs2_cleanmarker_oob(c)) {
 558                         /* scan oob, take care of cleanmarker */
 559                         int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
 560                         D2(printk(KERN_NOTICE "jffs2_check_oob_empty returned %d\n",ret));
 561                         switch (ret) {
 562                         case 0:         return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
 563                         case 1:         return BLK_STATE_ALLDIRTY;
 564                         default:        return ret;
 565                         }
 566                 }
 567 #endif
 568                 D1(printk(KERN_DEBUG "Block at 0x%08x is empty (erased)\n", jeb->offset));
 569                 if (c->cleanmarker_size == 0)
 570                         return BLK_STATE_CLEANMARKER;   /* don't bother with re-erase */
 571                 else
 572                         return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
 573         }
 574         if (ofs) {
 575                 D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset,
 576                           jeb->offset + ofs));
 577                 if ((err = jffs2_prealloc_raw_node_refs(c, jeb, 1)))
 578                         return err;
 579                 if ((err = jffs2_scan_dirty_space(c, jeb, ofs)))
 580                         return err;
 581         }
 582
 583         /* Now ofs is a complete physical flash offset as it always was... */
 584         ofs += jeb->offset;
 585
 586         noise = 10;
 587
 588         dbg_summary("no summary found in jeb 0x%08x. Apply original scan.\n",jeb->offset);
 589
 590 scan_more:
 591         while(ofs < jeb->offset + c->sector_size) {
 592
 593                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 594
 595                 /* Make sure there are node refs available for use */
 596                 err = jffs2_prealloc_raw_node_refs(c, jeb, 2);
 597                 if (err)
 598                         return err;
 599
 600                 cond_resched();
 601
 602                 if (ofs & 3) {
 603                         printk(KERN_WARNING "Eep. ofs 0x%08x not word-aligned!\n", ofs);
 604                         ofs = PAD(ofs);
 605                         continue;
 606                 }
 607                 if (ofs == prevofs) {
 608                         printk(KERN_WARNING "ofs 0x%08x has already been seen. Skipping\n", ofs);
 609                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 610                                 return err;
 611                         ofs += 4;
 612                         continue;
 613                 }
 614                 prevofs = ofs;
 615
 616                 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
 617                         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),
 618                                   jeb->offset, c->sector_size, ofs, sizeof(*node)));
 619                         if ((err = jffs2_scan_dirty_space(c, jeb, (jeb->offset + c->sector_size)-ofs)))
 620                                 return err;
 621                         break;
 622                 }
 623
 624                 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
 625                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 626                         D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
 627                                   sizeof(struct jffs2_unknown_node), buf_len, ofs));
 628                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 629                         if (err)
 630                                 return err;
 631                         buf_ofs = ofs;
 632                 }
 633
 634                 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
 635
 636                 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
 637                         uint32_t inbuf_ofs;
 638                         uint32_t empty_start, scan_end;
 639
 640                         empty_start = ofs;
 641                         ofs += 4;
 642                         scan_end = min_t(uint32_t, EMPTY_SCAN_SIZE(c->sector_size)/8, buf_len);
 643
 644                         D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs));
 645                 more_empty:
 646                         inbuf_ofs = ofs - buf_ofs;
 647                         while (inbuf_ofs < scan_end) {
 648                                 if (unlikely(*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff)) {
 649                                         printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n",
 650                                                empty_start, ofs);
 651                                         if ((err = jffs2_scan_dirty_space(c, jeb, ofs-empty_start)))
 652                                                 return err;
 653                                         goto scan_more;
 654                                 }
 655
 656                                 inbuf_ofs+=4;
 657                                 ofs += 4;
 658                         }
 659                         /* Ran off end. */
 660                         D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs));
 661
 662                         /* If we're only checking the beginning of a block with a cleanmarker,
 663                            bail now */
 664                         if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&
 665                             c->cleanmarker_size && !jeb->dirty_size && !ref_next(jeb->first_node)) {
 666                                 D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE(c->sector_size)));
 667                                 return BLK_STATE_CLEANMARKER;
 668                         }
 669                         if (!buf_size && (scan_end != buf_len)) {/* XIP/point case */
 670                                 scan_end = buf_len;
 671                                 goto more_empty;
 672                         }
 673
 674                         /* See how much more there is to read in this eraseblock... */
 675                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 676                         if (!buf_len) {
 677                                 /* No more to read. Break out of main loop without marking
 678                                    this range of empty space as dirty (because it's not) */
 679                                 D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block. Treating as free_space\n",
 680                                           empty_start));
 681                                 break;
 682                         }
 683                         /* point never reaches here */
 684                         scan_end = buf_len;
 685                         D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs));
 686                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 687                         if (err)
 688                                 return err;
 689                         buf_ofs = ofs;
 690                         goto more_empty;
 691                 }
 692
 693                 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
 694                         printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n", ofs);
 695                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 696                                 return err;
 697                         ofs += 4;
 698                         continue;
 699                 }
 700                 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
 701                         D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs));
 702                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 703                                 return err;
 704                         ofs += 4;
 705                         continue;
 706                 }
 707                 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
 708                         printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08x\n", ofs);
 709                         printk(KERN_WARNING "You cannot use older JFFS2 filesystems with newer kernels\n");
 710                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 711                                 return err;
 712                         ofs += 4;
 713                         continue;
 714                 }
 715                 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
 716                         /* OK. We're out of possibilities. Whinge and move on */
 717                         noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n",
 718                                      JFFS2_MAGIC_BITMASK, ofs,
 719                                      je16_to_cpu(node->magic));
 720                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 721                                 return err;
 722                         ofs += 4;
 723                         continue;
 724                 }
 725                 /* We seem to have a node of sorts. Check the CRC */
 726                 crcnode.magic = node->magic;
 727                 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
 728                 crcnode.totlen = node->totlen;
 729                 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
 730
 731                 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
 732                         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",
 733                                      ofs, je16_to_cpu(node->magic),
 734                                      je16_to_cpu(node->nodetype),
 735                                      je32_to_cpu(node->totlen),
 736                                      je32_to_cpu(node->hdr_crc),
 737                                      hdr_crc);
 738                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 739                                 return err;
 740                         ofs += 4;
 741                         continue;
 742                 }
 743
 744                 if (ofs + je32_to_cpu(node->totlen) > jeb->offset + c->sector_size) {
 745                         /* Eep. Node goes over the end of the erase block. */
 746                         printk(KERN_WARNING "Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
 747                                ofs, je32_to_cpu(node->totlen));
 748                         printk(KERN_WARNING "Perhaps the file system was created with the wrong erase size?\n");
 749                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 750                                 return err;
 751                         ofs += 4;
 752                         continue;
 753                 }
 754
 755                 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
 756                         /* Wheee. This is an obsoleted node */
 757                         D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs));
 758                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 759                                 return err;
 760                         ofs += PAD(je32_to_cpu(node->totlen));
 761                         continue;
 762                 }
 763
 764                 switch(je16_to_cpu(node->nodetype)) {
 765                 case JFFS2_NODETYPE_INODE:
 766                         if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
 767                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 768                                 D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
 769                                           sizeof(struct jffs2_raw_inode), 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_inode_node(c, jeb, (void *)node, ofs, s);
 777                         if (err) return err;
 778                         ofs += PAD(je32_to_cpu(node->totlen));
 779                         break;
 780
 781                 case JFFS2_NODETYPE_DIRENT:
 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 (dirent node) 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_dirent_node(c, jeb, (void *)node, ofs, s);
 793                         if (err) return err;
 794                         ofs += PAD(je32_to_cpu(node->totlen));
 795                         break;
 796
 797 #ifdef CONFIG_JFFS2_FS_XATTR
 798                 case JFFS2_NODETYPE_XATTR:
 799                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 800                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 801                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (xattr node)"
 802                                           " left to end of buf. Reading 0x%x at 0x%08x\n",
 803                                           je32_to_cpu(node->totlen), buf_len, ofs));
 804                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 805                                 if (err)
 806                                         return err;
 807                                 buf_ofs = ofs;
 808                                 node = (void *)buf;
 809                         }
 810                         err = jffs2_scan_xattr_node(c, jeb, (void *)node, ofs, s);
 811                         if (err)
 812                                 return err;
 813                         ofs += PAD(je32_to_cpu(node->totlen));
 814                         break;
 815                 case JFFS2_NODETYPE_XREF:
 816                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 817                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 818                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (xref node)"
 819                                           " left to end of buf. Reading 0x%x at 0x%08x\n",
 820                                           je32_to_cpu(node->totlen), buf_len, ofs));
 821                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 822                                 if (err)
 823                                         return err;
 824                                 buf_ofs = ofs;
 825                                 node = (void *)buf;
 826                         }
 827                         err = jffs2_scan_xref_node(c, jeb, (void *)node, ofs, s);
 828                         if (err)
 829                                 return err;
 830                         ofs += PAD(je32_to_cpu(node->totlen));
 831                         break;
 832 #endif  /* CONFIG_JFFS2_FS_XATTR */
 833
 834                 case JFFS2_NODETYPE_CLEANMARKER:
 835                         D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs));
 836                         if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
 837                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n",
 838                                        ofs, je32_to_cpu(node->totlen), c->cleanmarker_size);
 839                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
 840                                         return err;
 841                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 842                         } else if (jeb->first_node) {
 843                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n", ofs, jeb->offset);
 844                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
 845                                         return err;
 846                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 847                         } else {
 848                                 jffs2_link_node_ref(c, jeb, ofs | REF_NORMAL, c->cleanmarker_size, NULL);
 849
 850                                 ofs += PAD(c->cleanmarker_size);
 851                         }
 852                         break;
 853
 854                 case JFFS2_NODETYPE_PADDING:
 855                         if (jffs2_sum_active())
 856                                 jffs2_sum_add_padding_mem(s, je32_to_cpu(node->totlen));
 857                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 858                                 return err;
 859                         ofs += PAD(je32_to_cpu(node->totlen));
 860                         break;
 861
 862                 default:
 863                         switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
 864                         case JFFS2_FEATURE_ROCOMPAT:
 865                                 printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 866                                 c->flags |= JFFS2_SB_FLAG_RO;
 867                                 if (!(jffs2_is_readonly(c)))
 868                                         return -EROFS;
 869                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 870                                         return err;
 871                                 ofs += PAD(je32_to_cpu(node->totlen));
 872                                 break;
 873
 874                         case JFFS2_FEATURE_INCOMPAT:
 875                                 printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 876                                 return -EINVAL;
 877
 878                         case JFFS2_FEATURE_RWCOMPAT_DELETE:
 879                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 880                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 881                                         return err;
 882                                 ofs += PAD(je32_to_cpu(node->totlen));
 883                                 break;
 884
 885                         case JFFS2_FEATURE_RWCOMPAT_COPY: {
 886                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 887
 888                                 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(node->totlen)), NULL);
 889
 890                                 /* We can't summarise nodes we don't grok */
 891                                 jffs2_sum_disable_collecting(s);
 892                                 ofs += PAD(je32_to_cpu(node->totlen));
 893                                 break;
 894                                 }
 895                         }
 896                 }
 897         }
 898
 899         if (jffs2_sum_active()) {
 900                 if (PAD(s->sum_size + JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size) {
 901                         dbg_summary("There is not enough space for "
 902                                 "summary information, disabling for this jeb!\n");
 903                         jffs2_sum_disable_collecting(s);
 904                 }
 905         }
 906
 907         D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x, wasted 0x%08x\n",
 908                   jeb->offset,jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size, jeb->wasted_size));
 909
 910         /* mark_node_obsolete can add to wasted !! */
 911         if (jeb->wasted_size) {
 912                 jeb->dirty_size += jeb->wasted_size;
 913                 c->dirty_size += jeb->wasted_size;
 914                 c->wasted_size -= jeb->wasted_size;
 915                 jeb->wasted_size = 0;
 916         }
 917
 918         return jffs2_scan_classify_jeb(c, jeb);
 919 }
 920
 921 struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
 922 {
 923         struct jffs2_inode_cache *ic;
 924
 925         ic = jffs2_get_ino_cache(c, ino);
 926         if (ic)
 927                 return ic;
 928
 929         if (ino > c->highest_ino)
 930                 c->highest_ino = ino;
 931
 932         ic = jffs2_alloc_inode_cache();
 933         if (!ic) {
 934                 printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n");
 935                 return NULL;
 936         }
 937         memset(ic, 0, sizeof(*ic));
 938
 939         ic->ino = ino;
 940         ic->nodes = (void *)ic;
 941         jffs2_add_ino_cache(c, ic);
 942         if (ino == 1)
 943                 ic->nlink = 1;
 944         return ic;
 945 }
 946
 947 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 948                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s)
 949 {
 950         struct jffs2_inode_cache *ic;
 951         uint32_t crc, ino = je32_to_cpu(ri->ino);
 952
 953         D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs));
 954
 955         /* We do very little here now. Just check the ino# to which we should attribute
 956            this node; we can do all the CRC checking etc. later. There's a tradeoff here --
 957            we used to scan the flash once only, reading everything we want from it into
 958            memory, then building all our in-core data structures and freeing the extra
 959            information. Now we allow the first part of the mount to complete a lot quicker,
 960            but we have to go _back_ to the flash in order to finish the CRC checking, etc.
 961            Which means that the _full_ amount of time to get to proper write mode with GC
 962            operational may actually be _longer_ than before. Sucks to be me. */
 963
 964         /* Check the node CRC in any case. */
 965         crc = crc32(0, ri, sizeof(*ri)-8);
 966         if (crc != je32_to_cpu(ri->node_crc)) {
 967                 printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on "
 968                        "node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 969                        ofs, je32_to_cpu(ri->node_crc), crc);
 970                 /*
 971                  * We believe totlen because the CRC on the node
 972                  * _header_ was OK, just the node itself failed.
 973                  */
 974                 return jffs2_scan_dirty_space(c, jeb,
 975                                               PAD(je32_to_cpu(ri->totlen)));
 976         }
 977
 978         ic = jffs2_get_ino_cache(c, ino);
 979         if (!ic) {
 980                 ic = jffs2_scan_make_ino_cache(c, ino);
 981                 if (!ic)
 982                         return -ENOMEM;
 983         }
 984
 985         /* Wheee. It worked */
 986         jffs2_link_node_ref(c, jeb, ofs | REF_UNCHECKED, PAD(je32_to_cpu(ri->totlen)), ic);
 987
 988         D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
 989                   je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
 990                   je32_to_cpu(ri->offset),
 991                   je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize)));
 992
 993         pseudo_random += je32_to_cpu(ri->version);
 994
 995         if (jffs2_sum_active()) {
 996                 jffs2_sum_add_inode_mem(s, ri, ofs - jeb->offset);
 997         }
 998
 999         return 0;
1000 }
1001
1002 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
1003                                   struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s)
1004 {
1005         struct jffs2_full_dirent *fd;
1006         struct jffs2_inode_cache *ic;
1007         uint32_t checkedlen;
1008         uint32_t crc;
1009         int err;
1010
1011         D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs));
1012
1013         /* We don't get here unless the node is still valid, so we don't have to
1014            mask in the ACCURATE bit any more. */
1015         crc = crc32(0, rd, sizeof(*rd)-8);
1016
1017         if (crc != je32_to_cpu(rd->node_crc)) {
1018                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1019                        ofs, je32_to_cpu(rd->node_crc), crc);
1020                 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
1021                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1022                         return err;
1023                 return 0;
1024         }
1025
1026         pseudo_random += je32_to_cpu(rd->version);
1027
1028         /* Should never happen. Did. (OLPC trac #4184)*/
1029         checkedlen = strnlen(rd->name, rd->nsize);
1030         if (checkedlen < rd->nsize) {
1031                 printk(KERN_ERR "Dirent at %08x has zeroes in name. Truncating to %d chars\n",
1032                        ofs, checkedlen);
1033         }
1034         fd = jffs2_alloc_full_dirent(checkedlen+1);
1035         if (!fd) {
1036                 return -ENOMEM;
1037         }
1038         memcpy(&fd->name, rd->name, checkedlen);
1039         fd->name[checkedlen] = 0;
1040
1041         crc = crc32(0, fd->name, rd->nsize);
1042         if (crc != je32_to_cpu(rd->name_crc)) {
1043                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1044                        ofs, je32_to_cpu(rd->name_crc), crc);
1045                 D1(printk(KERN_NOTICE "Name for which CRC failed is (now) '%s', ino #%d\n", fd->name, je32_to_cpu(rd->ino)));
1046                 jffs2_free_full_dirent(fd);
1047                 /* FIXME: Why do we believe totlen? */
1048                 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
1049                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1050                         return err;
1051                 return 0;
1052         }
1053         ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
1054         if (!ic) {
1055                 jffs2_free_full_dirent(fd);
1056                 return -ENOMEM;
1057         }
1058
1059         fd->raw = jffs2_link_node_ref(c, jeb, ofs | dirent_node_state(rd),
1060                                       PAD(je32_to_cpu(rd->totlen)), ic);
1061
1062         fd->next = NULL;
1063         fd->version = je32_to_cpu(rd->version);
1064         fd->ino = je32_to_cpu(rd->ino);
1065         fd->nhash = full_name_hash(fd->name, checkedlen);
1066         fd->type = rd->type;
1067         jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
1068
1069         if (jffs2_sum_active()) {
1070                 jffs2_sum_add_dirent_mem(s, rd, ofs - jeb->offset);
1071         }
1072
1073         return 0;
1074 }
1075
1076 static int count_list(struct list_head *l)
1077 {
1078         uint32_t count = 0;
1079         struct list_head *tmp;
1080
1081         list_for_each(tmp, l) {
1082                 count++;
1083         }
1084         return count;
1085 }
1086
1087 /* Note: This breaks if list_empty(head). I don't care. You
1088    might, if you copy this code and use it elsewhere :) */
1089 static void rotate_list(struct list_head *head, uint32_t count)
1090 {
1091         struct list_head *n = head->next;
1092
1093         list_del(head);
1094         while(count--) {
1095                 n = n->next;
1096         }
1097         list_add(head, n);
1098 }
1099
1100 void jffs2_rotate_lists(struct jffs2_sb_info *c)
1101 {
1102         uint32_t x;
1103         uint32_t rotateby;
1104
1105         x = count_list(&c->clean_list);
1106         if (x) {
1107                 rotateby = pseudo_random % x;
1108                 rotate_list((&c->clean_list), rotateby);
1109         }
1110
1111         x = count_list(&c->very_dirty_list);
1112         if (x) {
1113                 rotateby = pseudo_random % x;
1114                 rotate_list((&c->very_dirty_list), rotateby);
1115         }
1116
1117         x = count_list(&c->dirty_list);
1118         if (x) {
1119                 rotateby = pseudo_random % x;
1120                 rotate_list((&c->dirty_list), rotateby);
1121         }
1122
1123         x = count_list(&c->erasable_list);
1124         if (x) {
1125                 rotateby = pseudo_random % x;
1126                 rotate_list((&c->erasable_list), rotateby);
1127         }
1128
1129         if (c->nr_erasing_blocks) {
1130                 rotateby = pseudo_random % c->nr_erasing_blocks;
1131                 rotate_list((&c->erase_pending_list), rotateby);
1132         }
1133
1134         if (c->nr_free_blocks) {
1135                 rotateby = pseudo_random % c->nr_free_blocks;
1136                 rotate_list((&c->free_list), rotateby);
1137         }
1138 }