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 256
  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, try_size;
  98
  99         ret = mtd_point(c->mtd, 0, c->mtd->size, &pointlen,
 100                         (void **)&flashbuf, NULL);
 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                 mtd_unpoint(c->mtd, 0, pointlen);
 105                 flashbuf = NULL;
 106         }
 107         if (ret && ret != -EOPNOTSUPP)
 108                 D1(printk(KERN_DEBUG "MTD point failed %d\n", ret));
 109 #endif
 110         if (!flashbuf) {
 111                 /* For NAND it's quicker to read a whole eraseblock at a time,
 112                    apparently */
 113                 if (jffs2_cleanmarker_oob(c))
 114                         try_size = c->sector_size;
 115                 else
 116                         try_size = PAGE_SIZE;
 117
 118                 D1(printk(KERN_DEBUG "Trying to allocate readbuf of %zu "
 119                         "bytes\n", try_size));
 120
 121                 flashbuf = mtd_kmalloc_up_to(c->mtd, &try_size);
 122                 if (!flashbuf)
 123                         return -ENOMEM;
 124
 125                 D1(printk(KERN_DEBUG "Allocated readbuf of %zu bytes\n",
 126                         try_size));
 127
 128                 buf_size = (uint32_t)try_size;
 129         }
 130
 131         if (jffs2_sum_active()) {
 132                 s = kzalloc(sizeof(struct jffs2_summary), GFP_KERNEL);
 133                 if (!s) {
 134                         JFFS2_WARNING("Can't allocate memory for summary\n");
 135                         ret = -ENOMEM;
 136                         goto out;
 137                 }
 138         }
 139
 140         for (i=0; i<c->nr_blocks; i++) {
 141                 struct jffs2_eraseblock *jeb = &c->blocks[i];
 142
 143                 cond_resched();
 144
 145                 /* reset summary info for next eraseblock scan */
 146                 jffs2_sum_reset_collected(s);
 147
 148                 ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset),
 149                                                 buf_size, s);
 150
 151                 if (ret < 0)
 152                         goto out;
 153
 154                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 155
 156                 /* Now decide which list to put it on */
 157                 switch(ret) {
 158                 case BLK_STATE_ALLFF:
 159                         /*
 160                          * Empty block.   Since we can't be sure it
 161                          * was entirely erased, we just queue it for erase
 162                          * again.  It will be marked as such when the erase
 163                          * is complete.  Meanwhile we still count it as empty
 164                          * for later checks.
 165                          */
 166                         empty_blocks++;
 167                         list_add(&jeb->list, &c->erase_pending_list);
 168                         c->nr_erasing_blocks++;
 169                         break;
 170
 171                 case BLK_STATE_CLEANMARKER:
 172                         /* Only a CLEANMARKER node is valid */
 173                         if (!jeb->dirty_size) {
 174                                 /* It's actually free */
 175                                 list_add(&jeb->list, &c->free_list);
 176                                 c->nr_free_blocks++;
 177                         } else {
 178                                 /* Dirt */
 179                                 D1(printk(KERN_DEBUG "Adding all-dirty block at 0x%08x to erase_pending_list\n", jeb->offset));
 180                                 list_add(&jeb->list, &c->erase_pending_list);
 181                                 c->nr_erasing_blocks++;
 182                         }
 183                         break;
 184
 185                 case BLK_STATE_CLEAN:
 186                         /* Full (or almost full) of clean data. Clean list */
 187                         list_add(&jeb->list, &c->clean_list);
 188                         break;
 189
 190                 case BLK_STATE_PARTDIRTY:
 191                         /* Some data, but not full. Dirty list. */
 192                         /* We want to remember the block with most free space
 193                         and stick it in the 'nextblock' position to start writing to it. */
 194                         if (jeb->free_size > min_free(c) &&
 195                                         (!c->nextblock || c->nextblock->free_size < jeb->free_size)) {
 196                                 /* Better candidate for the next writes to go to */
 197                                 if (c->nextblock) {
 198                                         ret = file_dirty(c, c->nextblock);
 199                                         if (ret)
 200                                                 goto out;
 201                                         /* deleting summary information of the old nextblock */
 202                                         jffs2_sum_reset_collected(c->summary);
 203                                 }
 204                                 /* update collected summary information for the current nextblock */
 205                                 jffs2_sum_move_collected(c, s);
 206                                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): new nextblock = 0x%08x\n", jeb->offset));
 207                                 c->nextblock = jeb;
 208                         } else {
 209                                 ret = file_dirty(c, jeb);
 210                                 if (ret)
 211                                         goto out;
 212                         }
 213                         break;
 214
 215                 case BLK_STATE_ALLDIRTY:
 216                         /* Nothing valid - not even a clean marker. Needs erasing. */
 217                         /* For now we just put it on the erasing list. We'll start the erases later */
 218                         D1(printk(KERN_NOTICE "JFFS2: Erase block at 0x%08x is not formatted. It will be erased\n", jeb->offset));
 219                         list_add(&jeb->list, &c->erase_pending_list);
 220                         c->nr_erasing_blocks++;
 221                         break;
 222
 223                 case BLK_STATE_BADBLOCK:
 224                         D1(printk(KERN_NOTICE "JFFS2: Block at 0x%08x is bad\n", jeb->offset));
 225                         list_add(&jeb->list, &c->bad_list);
 226                         c->bad_size += c->sector_size;
 227                         c->free_size -= c->sector_size;
 228                         bad_blocks++;
 229                         break;
 230                 default:
 231                         printk(KERN_WARNING "jffs2_scan_medium(): unknown block state\n");
 232                         BUG();
 233                 }
 234         }
 235
 236         /* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
 237         if (c->nextblock && (c->nextblock->dirty_size)) {
 238                 c->nextblock->wasted_size += c->nextblock->dirty_size;
 239                 c->wasted_size += c->nextblock->dirty_size;
 240                 c->dirty_size -= c->nextblock->dirty_size;
 241                 c->nextblock->dirty_size = 0;
 242         }
 243 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 244         if (!jffs2_can_mark_obsolete(c) && c->wbuf_pagesize && c->nextblock && (c->nextblock->free_size % c->wbuf_pagesize)) {
 245                 /* If we're going to start writing into a block which already
 246                    contains data, and the end of the data isn't page-aligned,
 247                    skip a little and align it. */
 248
 249                 uint32_t skip = c->nextblock->free_size % c->wbuf_pagesize;
 250
 251                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): Skipping %d bytes in nextblock to ensure page alignment\n",
 252                           skip));
 253                 jffs2_prealloc_raw_node_refs(c, c->nextblock, 1);
 254                 jffs2_scan_dirty_space(c, c->nextblock, skip);
 255         }
 256 #endif
 257         if (c->nr_erasing_blocks) {
 258                 if ( !c->used_size && ((c->nr_free_blocks+empty_blocks+bad_blocks)!= c->nr_blocks || bad_blocks == c->nr_blocks) ) {
 259                         printk(KERN_NOTICE "Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
 260                         printk(KERN_NOTICE "empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",empty_blocks,bad_blocks,c->nr_blocks);
 261                         ret = -EIO;
 262                         goto out;
 263                 }
 264                 spin_lock(&c->erase_completion_lock);
 265                 jffs2_garbage_collect_trigger(c);
 266                 spin_unlock(&c->erase_completion_lock);
 267         }
 268         ret = 0;
 269  out:
 270         if (buf_size)
 271                 kfree(flashbuf);
 272 #ifndef __ECOS
 273         else
 274                 mtd_unpoint(c->mtd, 0, c->mtd->size);
 275 #endif
 276         kfree(s);
 277         return ret;
 278 }
 279
 280 static int jffs2_fill_scan_buf(struct jffs2_sb_info *c, void *buf,
 281                                uint32_t ofs, uint32_t len)
 282 {
 283         int ret;
 284         size_t retlen;
 285
 286         ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
 287         if (ret) {
 288                 D1(printk(KERN_WARNING "mtd->read(0x%x bytes from 0x%x) returned %d\n", len, ofs, ret));
 289                 return ret;
 290         }
 291         if (retlen < len) {
 292                 D1(printk(KERN_WARNING "Read at 0x%x gave only 0x%zx bytes\n", ofs, retlen));
 293                 return -EIO;
 294         }
 295         return 0;
 296 }
 297
 298 int jffs2_scan_classify_jeb(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
 299 {
 300         if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size
 301             && (!jeb->first_node || !ref_next(jeb->first_node)) )
 302                 return BLK_STATE_CLEANMARKER;
 303
 304         /* move blocks with max 4 byte dirty space to cleanlist */
 305         else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
 306                 c->dirty_size -= jeb->dirty_size;
 307                 c->wasted_size += jeb->dirty_size;
 308                 jeb->wasted_size += jeb->dirty_size;
 309                 jeb->dirty_size = 0;
 310                 return BLK_STATE_CLEAN;
 311         } else if (jeb->used_size || jeb->unchecked_size)
 312                 return BLK_STATE_PARTDIRTY;
 313         else
 314                 return BLK_STATE_ALLDIRTY;
 315 }
 316
 317 #ifdef CONFIG_JFFS2_FS_XATTR
 318 static int jffs2_scan_xattr_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 319                                  struct jffs2_raw_xattr *rx, uint32_t ofs,
 320                                  struct jffs2_summary *s)
 321 {
 322         struct jffs2_xattr_datum *xd;
 323         uint32_t xid, version, totlen, crc;
 324         int err;
 325
 326         crc = crc32(0, rx, sizeof(struct jffs2_raw_xattr) - 4);
 327         if (crc != je32_to_cpu(rx->node_crc)) {
 328                 JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
 329                               ofs, je32_to_cpu(rx->node_crc), crc);
 330                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
 331                         return err;
 332                 return 0;
 333         }
 334
 335         xid = je32_to_cpu(rx->xid);
 336         version = je32_to_cpu(rx->version);
 337
 338         totlen = PAD(sizeof(struct jffs2_raw_xattr)
 339                         + rx->name_len + 1 + je16_to_cpu(rx->value_len));
 340         if (totlen != je32_to_cpu(rx->totlen)) {
 341                 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%u\n",
 342                               ofs, je32_to_cpu(rx->totlen), totlen);
 343                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
 344                         return err;
 345                 return 0;
 346         }
 347
 348         xd = jffs2_setup_xattr_datum(c, xid, version);
 349         if (IS_ERR(xd))
 350                 return PTR_ERR(xd);
 351
 352         if (xd->version > version) {
 353                 struct jffs2_raw_node_ref *raw
 354                         = jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, NULL);
 355                 raw->next_in_ino = xd->node->next_in_ino;
 356                 xd->node->next_in_ino = raw;
 357         } else {
 358                 xd->version = version;
 359                 xd->xprefix = rx->xprefix;
 360                 xd->name_len = rx->name_len;
 361                 xd->value_len = je16_to_cpu(rx->value_len);
 362                 xd->data_crc = je32_to_cpu(rx->data_crc);
 363
 364                 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, (void *)xd);
 365         }
 366
 367         if (jffs2_sum_active())
 368                 jffs2_sum_add_xattr_mem(s, rx, ofs - jeb->offset);
 369         dbg_xattr("scanning xdatum at %#08x (xid=%u, version=%u)\n",
 370                   ofs, xd->xid, xd->version);
 371         return 0;
 372 }
 373
 374 static int jffs2_scan_xref_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 375                                 struct jffs2_raw_xref *rr, uint32_t ofs,
 376                                 struct jffs2_summary *s)
 377 {
 378         struct jffs2_xattr_ref *ref;
 379         uint32_t crc;
 380         int err;
 381
 382         crc = crc32(0, rr, sizeof(*rr) - 4);
 383         if (crc != je32_to_cpu(rr->node_crc)) {
 384                 JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
 385                               ofs, je32_to_cpu(rr->node_crc), crc);
 386                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rr->totlen)))))
 387                         return err;
 388                 return 0;
 389         }
 390
 391         if (PAD(sizeof(struct jffs2_raw_xref)) != je32_to_cpu(rr->totlen)) {
 392                 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%zd\n",
 393                               ofs, je32_to_cpu(rr->totlen),
 394                               PAD(sizeof(struct jffs2_raw_xref)));
 395                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rr->totlen))))
 396                         return err;
 397                 return 0;
 398         }
 399
 400         ref = jffs2_alloc_xattr_ref();
 401         if (!ref)
 402                 return -ENOMEM;
 403
 404         /* BEFORE jffs2_build_xattr_subsystem() called,
 405          * and AFTER xattr_ref is marked as a dead xref,
 406          * ref->xid is used to store 32bit xid, xd is not used
 407          * ref->ino is used to store 32bit inode-number, ic is not used
 408          * Thoes variables are declared as union, thus using those
 409          * are exclusive. In a similar way, ref->next is temporarily
 410          * used to chain all xattr_ref object. It's re-chained to
 411          * jffs2_inode_cache in jffs2_build_xattr_subsystem() correctly.
 412          */
 413         ref->ino = je32_to_cpu(rr->ino);
 414         ref->xid = je32_to_cpu(rr->xid);
 415         ref->xseqno = je32_to_cpu(rr->xseqno);
 416         if (ref->xseqno > c->highest_xseqno)
 417                 c->highest_xseqno = (ref->xseqno & ~XREF_DELETE_MARKER);
 418         ref->next = c->xref_temp;
 419         c->xref_temp = ref;
 420
 421         jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(rr->totlen)), (void *)ref);
 422
 423         if (jffs2_sum_active())
 424                 jffs2_sum_add_xref_mem(s, rr, ofs - jeb->offset);
 425         dbg_xattr("scan xref at %#08x (xid=%u, ino=%u)\n",
 426                   ofs, ref->xid, ref->ino);
 427         return 0;
 428 }
 429 #endif
 430
 431 /* Called with 'buf_size == 0' if buf is in fact a pointer _directly_ into
 432    the flash, XIP-style */
 433 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 434                                   unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) {
 435         struct jffs2_unknown_node *node;
 436         struct jffs2_unknown_node crcnode;
 437         uint32_t ofs, prevofs, max_ofs;
 438         uint32_t hdr_crc, buf_ofs, buf_len;
 439         int err;
 440         int noise = 0;
 441
 442
 443 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 444         int cleanmarkerfound = 0;
 445 #endif
 446
 447         ofs = jeb->offset;
 448         prevofs = jeb->offset - 1;
 449
 450         D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs));
 451
 452 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 453         if (jffs2_cleanmarker_oob(c)) {
 454                 int ret;
 455
 456                 if (mtd_block_isbad(c->mtd, jeb->offset))
 457                         return BLK_STATE_BADBLOCK;
 458
 459                 ret = jffs2_check_nand_cleanmarker(c, jeb);
 460                 D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n",ret));
 461
 462                 /* Even if it's not found, we still scan to see
 463                    if the block is empty. We use this information
 464                    to decide whether to erase it or not. */
 465                 switch (ret) {
 466                 case 0:         cleanmarkerfound = 1; break;
 467                 case 1:         break;
 468                 default:        return ret;
 469                 }
 470         }
 471 #endif
 472
 473         if (jffs2_sum_active()) {
 474                 struct jffs2_sum_marker *sm;
 475                 void *sumptr = NULL;
 476                 uint32_t sumlen;
 477
 478                 if (!buf_size) {
 479                         /* XIP case. Just look, point at the summary if it's there */
 480                         sm = (void *)buf + c->sector_size - sizeof(*sm);
 481                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
 482                                 sumptr = buf + je32_to_cpu(sm->offset);
 483                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
 484                         }
 485                 } else {
 486                         /* If NAND flash, read a whole page of it. Else just the end */
 487                         if (c->wbuf_pagesize)
 488                                 buf_len = c->wbuf_pagesize;
 489                         else
 490                                 buf_len = sizeof(*sm);
 491
 492                         /* Read as much as we want into the _end_ of the preallocated buffer */
 493                         err = jffs2_fill_scan_buf(c, buf + buf_size - buf_len,
 494                                                   jeb->offset + c->sector_size - buf_len,
 495                                                   buf_len);
 496                         if (err)
 497                                 return err;
 498
 499                         sm = (void *)buf + buf_size - sizeof(*sm);
 500                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
 501                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
 502                                 sumptr = buf + buf_size - sumlen;
 503
 504                                 /* Now, make sure the summary itself is available */
 505                                 if (sumlen > buf_size) {
 506                                         /* Need to kmalloc for this. */
 507                                         sumptr = kmalloc(sumlen, GFP_KERNEL);
 508                                         if (!sumptr)
 509                                                 return -ENOMEM;
 510                                         memcpy(sumptr + sumlen - buf_len, buf + buf_size - buf_len, buf_len);
 511                                 }
 512                                 if (buf_len < sumlen) {
 513                                         /* Need to read more so that the entire summary node is present */
 514                                         err = jffs2_fill_scan_buf(c, sumptr,
 515                                                                   jeb->offset + c->sector_size - sumlen,
 516                                                                   sumlen - buf_len);
 517                                         if (err)
 518                                                 return err;
 519                                 }
 520                         }
 521
 522                 }
 523
 524                 if (sumptr) {
 525                         err = jffs2_sum_scan_sumnode(c, jeb, sumptr, sumlen, &pseudo_random);
 526
 527                         if (buf_size && sumlen > buf_size)
 528                                 kfree(sumptr);
 529                         /* If it returns with a real error, bail.
 530                            If it returns positive, that's a block classification
 531                            (i.e. BLK_STATE_xxx) so return that too.
 532                            If it returns zero, fall through to full scan. */
 533                         if (err)
 534                                 return err;
 535                 }
 536         }
 537
 538         buf_ofs = jeb->offset;
 539
 540         if (!buf_size) {
 541                 /* This is the XIP case -- we're reading _directly_ from the flash chip */
 542                 buf_len = c->sector_size;
 543         } else {
 544                 buf_len = EMPTY_SCAN_SIZE(c->sector_size);
 545                 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
 546                 if (err)
 547                         return err;
 548         }
 549
 550         /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
 551         ofs = 0;
 552         max_ofs = EMPTY_SCAN_SIZE(c->sector_size);
 553         /* Scan only EMPTY_SCAN_SIZE of 0xFF before declaring it's empty */
 554         while(ofs < max_ofs && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
 555                 ofs += 4;
 556
 557         if (ofs == max_ofs) {
 558 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 559                 if (jffs2_cleanmarker_oob(c)) {
 560                         /* scan oob, take care of cleanmarker */
 561                         int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
 562                         D2(printk(KERN_NOTICE "jffs2_check_oob_empty returned %d\n",ret));
 563                         switch (ret) {
 564                         case 0:         return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
 565                         case 1:         return BLK_STATE_ALLDIRTY;
 566                         default:        return ret;
 567                         }
 568                 }
 569 #endif
 570                 D1(printk(KERN_DEBUG "Block at 0x%08x is empty (erased)\n", jeb->offset));
 571                 if (c->cleanmarker_size == 0)
 572                         return BLK_STATE_CLEANMARKER;   /* don't bother with re-erase */
 573                 else
 574                         return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
 575         }
 576         if (ofs) {
 577                 D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset,
 578                           jeb->offset + ofs));
 579                 if ((err = jffs2_prealloc_raw_node_refs(c, jeb, 1)))
 580                         return err;
 581                 if ((err = jffs2_scan_dirty_space(c, jeb, ofs)))
 582                         return err;
 583         }
 584
 585         /* Now ofs is a complete physical flash offset as it always was... */
 586         ofs += jeb->offset;
 587
 588         noise = 10;
 589
 590         dbg_summary("no summary found in jeb 0x%08x. Apply original scan.\n",jeb->offset);
 591
 592 scan_more:
 593         while(ofs < jeb->offset + c->sector_size) {
 594
 595                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 596
 597                 /* Make sure there are node refs available for use */
 598                 err = jffs2_prealloc_raw_node_refs(c, jeb, 2);
 599                 if (err)
 600                         return err;
 601
 602                 cond_resched();
 603
 604                 if (ofs & 3) {
 605                         printk(KERN_WARNING "Eep. ofs 0x%08x not word-aligned!\n", ofs);
 606                         ofs = PAD(ofs);
 607                         continue;
 608                 }
 609                 if (ofs == prevofs) {
 610                         printk(KERN_WARNING "ofs 0x%08x has already been seen. Skipping\n", ofs);
 611                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 612                                 return err;
 613                         ofs += 4;
 614                         continue;
 615                 }
 616                 prevofs = ofs;
 617
 618                 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
 619                         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),
 620                                   jeb->offset, c->sector_size, ofs, sizeof(*node)));
 621                         if ((err = jffs2_scan_dirty_space(c, jeb, (jeb->offset + c->sector_size)-ofs)))
 622                                 return err;
 623                         break;
 624                 }
 625
 626                 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
 627                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 628                         D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
 629                                   sizeof(struct jffs2_unknown_node), buf_len, ofs));
 630                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 631                         if (err)
 632                                 return err;
 633                         buf_ofs = ofs;
 634                 }
 635
 636                 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
 637
 638                 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
 639                         uint32_t inbuf_ofs;
 640                         uint32_t empty_start, scan_end;
 641
 642                         empty_start = ofs;
 643                         ofs += 4;
 644                         scan_end = min_t(uint32_t, EMPTY_SCAN_SIZE(c->sector_size)/8, buf_len);
 645
 646                         D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs));
 647                 more_empty:
 648                         inbuf_ofs = ofs - buf_ofs;
 649                         while (inbuf_ofs < scan_end) {
 650                                 if (unlikely(*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff)) {
 651                                         printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n",
 652                                                empty_start, ofs);
 653                                         if ((err = jffs2_scan_dirty_space(c, jeb, ofs-empty_start)))
 654                                                 return err;
 655                                         goto scan_more;
 656                                 }
 657
 658                                 inbuf_ofs+=4;
 659                                 ofs += 4;
 660                         }
 661                         /* Ran off end. */
 662                         D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs));
 663
 664                         /* If we're only checking the beginning of a block with a cleanmarker,
 665                            bail now */
 666                         if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&
 667                             c->cleanmarker_size && !jeb->dirty_size && !ref_next(jeb->first_node)) {
 668                                 D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE(c->sector_size)));
 669                                 return BLK_STATE_CLEANMARKER;
 670                         }
 671                         if (!buf_size && (scan_end != buf_len)) {/* XIP/point case */
 672                                 scan_end = buf_len;
 673                                 goto more_empty;
 674                         }
 675
 676                         /* See how much more there is to read in this eraseblock... */
 677                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 678                         if (!buf_len) {
 679                                 /* No more to read. Break out of main loop without marking
 680                                    this range of empty space as dirty (because it's not) */
 681                                 D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block. Treating as free_space\n",
 682                                           empty_start));
 683                                 break;
 684                         }
 685                         /* point never reaches here */
 686                         scan_end = buf_len;
 687                         D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs));
 688                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 689                         if (err)
 690                                 return err;
 691                         buf_ofs = ofs;
 692                         goto more_empty;
 693                 }
 694
 695                 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
 696                         printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n", ofs);
 697                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 698                                 return err;
 699                         ofs += 4;
 700                         continue;
 701                 }
 702                 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
 703                         D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs));
 704                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 705                                 return err;
 706                         ofs += 4;
 707                         continue;
 708                 }
 709                 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
 710                         printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08x\n", ofs);
 711                         printk(KERN_WARNING "You cannot use older JFFS2 filesystems with newer kernels\n");
 712                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 713                                 return err;
 714                         ofs += 4;
 715                         continue;
 716                 }
 717                 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
 718                         /* OK. We're out of possibilities. Whinge and move on */
 719                         noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n",
 720                                      JFFS2_MAGIC_BITMASK, ofs,
 721                                      je16_to_cpu(node->magic));
 722                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 723                                 return err;
 724                         ofs += 4;
 725                         continue;
 726                 }
 727                 /* We seem to have a node of sorts. Check the CRC */
 728                 crcnode.magic = node->magic;
 729                 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
 730                 crcnode.totlen = node->totlen;
 731                 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
 732
 733                 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
 734                         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",
 735                                      ofs, je16_to_cpu(node->magic),
 736                                      je16_to_cpu(node->nodetype),
 737                                      je32_to_cpu(node->totlen),
 738                                      je32_to_cpu(node->hdr_crc),
 739                                      hdr_crc);
 740                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 741                                 return err;
 742                         ofs += 4;
 743                         continue;
 744                 }
 745
 746                 if (ofs + je32_to_cpu(node->totlen) > jeb->offset + c->sector_size) {
 747                         /* Eep. Node goes over the end of the erase block. */
 748                         printk(KERN_WARNING "Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
 749                                ofs, je32_to_cpu(node->totlen));
 750                         printk(KERN_WARNING "Perhaps the file system was created with the wrong erase size?\n");
 751                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 752                                 return err;
 753                         ofs += 4;
 754                         continue;
 755                 }
 756
 757                 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
 758                         /* Wheee. This is an obsoleted node */
 759                         D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs));
 760                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 761                                 return err;
 762                         ofs += PAD(je32_to_cpu(node->totlen));
 763                         continue;
 764                 }
 765
 766                 switch(je16_to_cpu(node->nodetype)) {
 767                 case JFFS2_NODETYPE_INODE:
 768                         if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
 769                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 770                                 D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
 771                                           sizeof(struct jffs2_raw_inode), buf_len, ofs));
 772                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 773                                 if (err)
 774                                         return err;
 775                                 buf_ofs = ofs;
 776                                 node = (void *)buf;
 777                         }
 778                         err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs, s);
 779                         if (err) return err;
 780                         ofs += PAD(je32_to_cpu(node->totlen));
 781                         break;
 782
 783                 case JFFS2_NODETYPE_DIRENT:
 784                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 785                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 786                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
 787                                           je32_to_cpu(node->totlen), buf_len, ofs));
 788                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 789                                 if (err)
 790                                         return err;
 791                                 buf_ofs = ofs;
 792                                 node = (void *)buf;
 793                         }
 794                         err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs, s);
 795                         if (err) return err;
 796                         ofs += PAD(je32_to_cpu(node->totlen));
 797                         break;
 798
 799 #ifdef CONFIG_JFFS2_FS_XATTR
 800                 case JFFS2_NODETYPE_XATTR:
 801                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 802                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 803                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (xattr node)"
 804                                           " left to end of buf. Reading 0x%x at 0x%08x\n",
 805                                           je32_to_cpu(node->totlen), buf_len, ofs));
 806                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 807                                 if (err)
 808                                         return err;
 809                                 buf_ofs = ofs;
 810                                 node = (void *)buf;
 811                         }
 812                         err = jffs2_scan_xattr_node(c, jeb, (void *)node, ofs, s);
 813                         if (err)
 814                                 return err;
 815                         ofs += PAD(je32_to_cpu(node->totlen));
 816                         break;
 817                 case JFFS2_NODETYPE_XREF:
 818                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 819                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 820                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (xref node)"
 821                                           " left to end of buf. Reading 0x%x at 0x%08x\n",
 822                                           je32_to_cpu(node->totlen), buf_len, ofs));
 823                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 824                                 if (err)
 825                                         return err;
 826                                 buf_ofs = ofs;
 827                                 node = (void *)buf;
 828                         }
 829                         err = jffs2_scan_xref_node(c, jeb, (void *)node, ofs, s);
 830                         if (err)
 831                                 return err;
 832                         ofs += PAD(je32_to_cpu(node->totlen));
 833                         break;
 834 #endif  /* CONFIG_JFFS2_FS_XATTR */
 835
 836                 case JFFS2_NODETYPE_CLEANMARKER:
 837                         D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs));
 838                         if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
 839                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n",
 840                                        ofs, je32_to_cpu(node->totlen), c->cleanmarker_size);
 841                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
 842                                         return err;
 843                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 844                         } else if (jeb->first_node) {
 845                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n", ofs, jeb->offset);
 846                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
 847                                         return err;
 848                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 849                         } else {
 850                                 jffs2_link_node_ref(c, jeb, ofs | REF_NORMAL, c->cleanmarker_size, NULL);
 851
 852                                 ofs += PAD(c->cleanmarker_size);
 853                         }
 854                         break;
 855
 856                 case JFFS2_NODETYPE_PADDING:
 857                         if (jffs2_sum_active())
 858                                 jffs2_sum_add_padding_mem(s, je32_to_cpu(node->totlen));
 859                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 860                                 return err;
 861                         ofs += PAD(je32_to_cpu(node->totlen));
 862                         break;
 863
 864                 default:
 865                         switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
 866                         case JFFS2_FEATURE_ROCOMPAT:
 867                                 printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 868                                 c->flags |= JFFS2_SB_FLAG_RO;
 869                                 if (!(jffs2_is_readonly(c)))
 870                                         return -EROFS;
 871                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 872                                         return err;
 873                                 ofs += PAD(je32_to_cpu(node->totlen));
 874                                 break;
 875
 876                         case JFFS2_FEATURE_INCOMPAT:
 877                                 printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 878                                 return -EINVAL;
 879
 880                         case JFFS2_FEATURE_RWCOMPAT_DELETE:
 881                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 882                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 883                                         return err;
 884                                 ofs += PAD(je32_to_cpu(node->totlen));
 885                                 break;
 886
 887                         case JFFS2_FEATURE_RWCOMPAT_COPY: {
 888                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 889
 890                                 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(node->totlen)), NULL);
 891
 892                                 /* We can't summarise nodes we don't grok */
 893                                 jffs2_sum_disable_collecting(s);
 894                                 ofs += PAD(je32_to_cpu(node->totlen));
 895                                 break;
 896                                 }
 897                         }
 898                 }
 899         }
 900
 901         if (jffs2_sum_active()) {
 902                 if (PAD(s->sum_size + JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size) {
 903                         dbg_summary("There is not enough space for "
 904                                 "summary information, disabling for this jeb!\n");
 905                         jffs2_sum_disable_collecting(s);
 906                 }
 907         }
 908
 909         D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x, wasted 0x%08x\n",
 910                   jeb->offset,jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size, jeb->wasted_size));
 911
 912         /* mark_node_obsolete can add to wasted !! */
 913         if (jeb->wasted_size) {
 914                 jeb->dirty_size += jeb->wasted_size;
 915                 c->dirty_size += jeb->wasted_size;
 916                 c->wasted_size -= jeb->wasted_size;
 917                 jeb->wasted_size = 0;
 918         }
 919
 920         return jffs2_scan_classify_jeb(c, jeb);
 921 }
 922
 923 struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
 924 {
 925         struct jffs2_inode_cache *ic;
 926
 927         ic = jffs2_get_ino_cache(c, ino);
 928         if (ic)
 929                 return ic;
 930
 931         if (ino > c->highest_ino)
 932                 c->highest_ino = ino;
 933
 934         ic = jffs2_alloc_inode_cache();
 935         if (!ic) {
 936                 printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n");
 937                 return NULL;
 938         }
 939         memset(ic, 0, sizeof(*ic));
 940
 941         ic->ino = ino;
 942         ic->nodes = (void *)ic;
 943         jffs2_add_ino_cache(c, ic);
 944         if (ino == 1)
 945                 ic->pino_nlink = 1;
 946         return ic;
 947 }
 948
 949 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 950                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s)
 951 {
 952         struct jffs2_inode_cache *ic;
 953         uint32_t crc, ino = je32_to_cpu(ri->ino);
 954
 955         D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs));
 956
 957         /* We do very little here now. Just check the ino# to which we should attribute
 958            this node; we can do all the CRC checking etc. later. There's a tradeoff here --
 959            we used to scan the flash once only, reading everything we want from it into
 960            memory, then building all our in-core data structures and freeing the extra
 961            information. Now we allow the first part of the mount to complete a lot quicker,
 962            but we have to go _back_ to the flash in order to finish the CRC checking, etc.
 963            Which means that the _full_ amount of time to get to proper write mode with GC
 964            operational may actually be _longer_ than before. Sucks to be me. */
 965
 966         /* Check the node CRC in any case. */
 967         crc = crc32(0, ri, sizeof(*ri)-8);
 968         if (crc != je32_to_cpu(ri->node_crc)) {
 969                 printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on "
 970                        "node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 971                        ofs, je32_to_cpu(ri->node_crc), crc);
 972                 /*
 973                  * We believe totlen because the CRC on the node
 974                  * _header_ was OK, just the node itself failed.
 975                  */
 976                 return jffs2_scan_dirty_space(c, jeb,
 977                                               PAD(je32_to_cpu(ri->totlen)));
 978         }
 979
 980         ic = jffs2_get_ino_cache(c, ino);
 981         if (!ic) {
 982                 ic = jffs2_scan_make_ino_cache(c, ino);
 983                 if (!ic)
 984                         return -ENOMEM;
 985         }
 986
 987         /* Wheee. It worked */
 988         jffs2_link_node_ref(c, jeb, ofs | REF_UNCHECKED, PAD(je32_to_cpu(ri->totlen)), ic);
 989
 990         D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
 991                   je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
 992                   je32_to_cpu(ri->offset),
 993                   je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize)));
 994
 995         pseudo_random += je32_to_cpu(ri->version);
 996
 997         if (jffs2_sum_active()) {
 998                 jffs2_sum_add_inode_mem(s, ri, ofs - jeb->offset);
 999         }
1000
1001         return 0;
1002 }
1003
1004 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
1005                                   struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s)
1006 {
1007         struct jffs2_full_dirent *fd;
1008         struct jffs2_inode_cache *ic;
1009         uint32_t checkedlen;
1010         uint32_t crc;
1011         int err;
1012
1013         D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs));
1014
1015         /* We don't get here unless the node is still valid, so we don't have to
1016            mask in the ACCURATE bit any more. */
1017         crc = crc32(0, rd, sizeof(*rd)-8);
1018
1019         if (crc != je32_to_cpu(rd->node_crc)) {
1020                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1021                        ofs, je32_to_cpu(rd->node_crc), crc);
1022                 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
1023                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1024                         return err;
1025                 return 0;
1026         }
1027
1028         pseudo_random += je32_to_cpu(rd->version);
1029
1030         /* Should never happen. Did. (OLPC trac #4184)*/
1031         checkedlen = strnlen(rd->name, rd->nsize);
1032         if (checkedlen < rd->nsize) {
1033                 printk(KERN_ERR "Dirent at %08x has zeroes in name. Truncating to %d chars\n",
1034                        ofs, checkedlen);
1035         }
1036         fd = jffs2_alloc_full_dirent(checkedlen+1);
1037         if (!fd) {
1038                 return -ENOMEM;
1039         }
1040         memcpy(&fd->name, rd->name, checkedlen);
1041         fd->name[checkedlen] = 0;
1042
1043         crc = crc32(0, fd->name, rd->nsize);
1044         if (crc != je32_to_cpu(rd->name_crc)) {
1045                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1046                        ofs, je32_to_cpu(rd->name_crc), crc);
1047                 D1(printk(KERN_NOTICE "Name for which CRC failed is (now) '%s', ino #%d\n", fd->name, je32_to_cpu(rd->ino)));
1048                 jffs2_free_full_dirent(fd);
1049                 /* FIXME: Why do we believe totlen? */
1050                 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
1051                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1052                         return err;
1053                 return 0;
1054         }
1055         ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
1056         if (!ic) {
1057                 jffs2_free_full_dirent(fd);
1058                 return -ENOMEM;
1059         }
1060
1061         fd->raw = jffs2_link_node_ref(c, jeb, ofs | dirent_node_state(rd),
1062                                       PAD(je32_to_cpu(rd->totlen)), ic);
1063
1064         fd->next = NULL;
1065         fd->version = je32_to_cpu(rd->version);
1066         fd->ino = je32_to_cpu(rd->ino);
1067         fd->nhash = full_name_hash(fd->name, checkedlen);
1068         fd->type = rd->type;
1069         jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
1070
1071         if (jffs2_sum_active()) {
1072                 jffs2_sum_add_dirent_mem(s, rd, ofs - jeb->offset);
1073         }
1074
1075         return 0;
1076 }
1077
1078 static int count_list(struct list_head *l)
1079 {
1080         uint32_t count = 0;
1081         struct list_head *tmp;
1082
1083         list_for_each(tmp, l) {
1084                 count++;
1085         }
1086         return count;
1087 }
1088
1089 /* Note: This breaks if list_empty(head). I don't care. You
1090    might, if you copy this code and use it elsewhere :) */
1091 static void rotate_list(struct list_head *head, uint32_t count)
1092 {
1093         struct list_head *n = head->next;
1094
1095         list_del(head);
1096         while(count--) {
1097                 n = n->next;
1098         }
1099         list_add(head, n);
1100 }
1101
1102 void jffs2_rotate_lists(struct jffs2_sb_info *c)
1103 {
1104         uint32_t x;
1105         uint32_t rotateby;
1106
1107         x = count_list(&c->clean_list);
1108         if (x) {
1109                 rotateby = pseudo_random % x;
1110                 rotate_list((&c->clean_list), rotateby);
1111         }
1112
1113         x = count_list(&c->very_dirty_list);
1114         if (x) {
1115                 rotateby = pseudo_random % x;
1116                 rotate_list((&c->very_dirty_list), rotateby);
1117         }
1118
1119         x = count_list(&c->dirty_list);
1120         if (x) {
1121                 rotateby = pseudo_random % x;
1122                 rotate_list((&c->dirty_list), rotateby);
1123         }
1124
1125         x = count_list(&c->erasable_list);
1126         if (x) {
1127                 rotateby = pseudo_random % x;
1128                 rotate_list((&c->erasable_list), rotateby);
1129         }
1130
1131         if (c->nr_erasing_blocks) {
1132                 rotateby = pseudo_random % c->nr_erasing_blocks;
1133                 rotate_list((&c->erase_pending_list), rotateby);
1134         }
1135
1136         if (c->nr_free_blocks) {
1137                 rotateby = pseudo_random % c->nr_free_blocks;
1138                 rotate_list((&c->free_list), rotateby);
1139         }
1140 }