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         if (c->mtd->point) {
 100                 ret = c->mtd->point(c->mtd, 0, c->mtd->size, &pointlen,
 101                                     (void **)&flashbuf, NULL);
 102                 if (!ret && pointlen < c->mtd->size) {
 103                         /* Don't muck about if it won't let us point to the whole flash */
 104                         D1(printk(KERN_DEBUG "MTD point returned len too short: 0x%zx\n", pointlen));
 105                         c->mtd->unpoint(c->mtd, 0, pointlen);
 106                         flashbuf = NULL;
 107                 }
 108                 if (ret)
 109                         D1(printk(KERN_DEBUG "MTD point failed %d\n", ret));
 110         }
 111 #endif
 112         if (!flashbuf) {
 113                 /* For NAND it's quicker to read a whole eraseblock at a time,
 114                    apparently */
 115                 if (jffs2_cleanmarker_oob(c))
 116                         try_size = c->sector_size;
 117                 else
 118                         try_size = PAGE_SIZE;
 119
 120                 D1(printk(KERN_DEBUG "Trying to allocate readbuf of %zu "
 121                         "bytes\n", try_size));
 122
 123                 flashbuf = mtd_kmalloc_up_to(c->mtd, &try_size);
 124                 if (!flashbuf)
 125                         return -ENOMEM;
 126
 127                 D1(printk(KERN_DEBUG "Allocated readbuf of %zu bytes\n",
 128                         try_size));
 129
 130                 buf_size = (uint32_t)try_size;
 131         }
 132
 133         if (jffs2_sum_active()) {
 134                 s = kzalloc(sizeof(struct jffs2_summary), GFP_KERNEL);
 135                 if (!s) {
 136                         JFFS2_WARNING("Can't allocate memory for summary\n");
 137                         ret = -ENOMEM;
 138                         goto out;
 139                 }
 140         }
 141
 142         for (i=0; i<c->nr_blocks; i++) {
 143                 struct jffs2_eraseblock *jeb = &c->blocks[i];
 144
 145                 cond_resched();
 146
 147                 /* reset summary info for next eraseblock scan */
 148                 jffs2_sum_reset_collected(s);
 149
 150                 ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset),
 151                                                 buf_size, s);
 152
 153                 if (ret < 0)
 154                         goto out;
 155
 156                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 157
 158                 /* Now decide which list to put it on */
 159                 switch(ret) {
 160                 case BLK_STATE_ALLFF:
 161                         /*
 162                          * Empty block.   Since we can't be sure it
 163                          * was entirely erased, we just queue it for erase
 164                          * again.  It will be marked as such when the erase
 165                          * is complete.  Meanwhile we still count it as empty
 166                          * for later checks.
 167                          */
 168                         empty_blocks++;
 169                         list_add(&jeb->list, &c->erase_pending_list);
 170                         c->nr_erasing_blocks++;
 171                         break;
 172
 173                 case BLK_STATE_CLEANMARKER:
 174                         /* Only a CLEANMARKER node is valid */
 175                         if (!jeb->dirty_size) {
 176                                 /* It's actually free */
 177                                 list_add(&jeb->list, &c->free_list);
 178                                 c->nr_free_blocks++;
 179                         } else {
 180                                 /* Dirt */
 181                                 D1(printk(KERN_DEBUG "Adding all-dirty block at 0x%08x to erase_pending_list\n", jeb->offset));
 182                                 list_add(&jeb->list, &c->erase_pending_list);
 183                                 c->nr_erasing_blocks++;
 184                         }
 185                         break;
 186
 187                 case BLK_STATE_CLEAN:
 188                         /* Full (or almost full) of clean data. Clean list */
 189                         list_add(&jeb->list, &c->clean_list);
 190                         break;
 191
 192                 case BLK_STATE_PARTDIRTY:
 193                         /* Some data, but not full. Dirty list. */
 194                         /* We want to remember the block with most free space
 195                         and stick it in the 'nextblock' position to start writing to it. */
 196                         if (jeb->free_size > min_free(c) &&
 197                                         (!c->nextblock || c->nextblock->free_size < jeb->free_size)) {
 198                                 /* Better candidate for the next writes to go to */
 199                                 if (c->nextblock) {
 200                                         ret = file_dirty(c, c->nextblock);
 201                                         if (ret)
 202                                                 goto out;
 203                                         /* deleting summary information of the old nextblock */
 204                                         jffs2_sum_reset_collected(c->summary);
 205                                 }
 206                                 /* update collected summary information for the current nextblock */
 207                                 jffs2_sum_move_collected(c, s);
 208                                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): new nextblock = 0x%08x\n", jeb->offset));
 209                                 c->nextblock = jeb;
 210                         } else {
 211                                 ret = file_dirty(c, jeb);
 212                                 if (ret)
 213                                         goto out;
 214                         }
 215                         break;
 216
 217                 case BLK_STATE_ALLDIRTY:
 218                         /* Nothing valid - not even a clean marker. Needs erasing. */
 219                         /* For now we just put it on the erasing list. We'll start the erases later */
 220                         D1(printk(KERN_NOTICE "JFFS2: Erase block at 0x%08x is not formatted. It will be erased\n", jeb->offset));
 221                         list_add(&jeb->list, &c->erase_pending_list);
 222                         c->nr_erasing_blocks++;
 223                         break;
 224
 225                 case BLK_STATE_BADBLOCK:
 226                         D1(printk(KERN_NOTICE "JFFS2: Block at 0x%08x is bad\n", jeb->offset));
 227                         list_add(&jeb->list, &c->bad_list);
 228                         c->bad_size += c->sector_size;
 229                         c->free_size -= c->sector_size;
 230                         bad_blocks++;
 231                         break;
 232                 default:
 233                         printk(KERN_WARNING "jffs2_scan_medium(): unknown block state\n");
 234                         BUG();
 235                 }
 236         }
 237
 238         /* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
 239         if (c->nextblock && (c->nextblock->dirty_size)) {
 240                 c->nextblock->wasted_size += c->nextblock->dirty_size;
 241                 c->wasted_size += c->nextblock->dirty_size;
 242                 c->dirty_size -= c->nextblock->dirty_size;
 243                 c->nextblock->dirty_size = 0;
 244         }
 245 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 246         if (!jffs2_can_mark_obsolete(c) && c->wbuf_pagesize && c->nextblock && (c->nextblock->free_size % c->wbuf_pagesize)) {
 247                 /* If we're going to start writing into a block which already
 248                    contains data, and the end of the data isn't page-aligned,
 249                    skip a little and align it. */
 250
 251                 uint32_t skip = c->nextblock->free_size % c->wbuf_pagesize;
 252
 253                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): Skipping %d bytes in nextblock to ensure page alignment\n",
 254                           skip));
 255                 jffs2_prealloc_raw_node_refs(c, c->nextblock, 1);
 256                 jffs2_scan_dirty_space(c, c->nextblock, skip);
 257         }
 258 #endif
 259         if (c->nr_erasing_blocks) {
 260                 if ( !c->used_size && ((c->nr_free_blocks+empty_blocks+bad_blocks)!= c->nr_blocks || bad_blocks == c->nr_blocks) ) {
 261                         printk(KERN_NOTICE "Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
 262                         printk(KERN_NOTICE "empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",empty_blocks,bad_blocks,c->nr_blocks);
 263                         ret = -EIO;
 264                         goto out;
 265                 }
 266                 spin_lock(&c->erase_completion_lock);
 267                 jffs2_garbage_collect_trigger(c);
 268                 spin_unlock(&c->erase_completion_lock);
 269         }
 270         ret = 0;
 271  out:
 272         if (buf_size)
 273                 kfree(flashbuf);
 274 #ifndef __ECOS
 275         else
 276                 c->mtd->unpoint(c->mtd, 0, c->mtd->size);
 277 #endif
 278         if (s)
 279                 kfree(s);
 280
 281         return ret;
 282 }
 283
 284 static int jffs2_fill_scan_buf(struct jffs2_sb_info *c, void *buf,
 285                                uint32_t ofs, uint32_t len)
 286 {
 287         int ret;
 288         size_t retlen;
 289
 290         ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
 291         if (ret) {
 292                 D1(printk(KERN_WARNING "mtd->read(0x%x bytes from 0x%x) returned %d\n", len, ofs, ret));
 293                 return ret;
 294         }
 295         if (retlen < len) {
 296                 D1(printk(KERN_WARNING "Read at 0x%x gave only 0x%zx bytes\n", ofs, retlen));
 297                 return -EIO;
 298         }
 299         return 0;
 300 }
 301
 302 int jffs2_scan_classify_jeb(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
 303 {
 304         if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size
 305             && (!jeb->first_node || !ref_next(jeb->first_node)) )
 306                 return BLK_STATE_CLEANMARKER;
 307
 308         /* move blocks with max 4 byte dirty space to cleanlist */
 309         else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
 310                 c->dirty_size -= jeb->dirty_size;
 311                 c->wasted_size += jeb->dirty_size;
 312                 jeb->wasted_size += jeb->dirty_size;
 313                 jeb->dirty_size = 0;
 314                 return BLK_STATE_CLEAN;
 315         } else if (jeb->used_size || jeb->unchecked_size)
 316                 return BLK_STATE_PARTDIRTY;
 317         else
 318                 return BLK_STATE_ALLDIRTY;
 319 }
 320
 321 #ifdef CONFIG_JFFS2_FS_XATTR
 322 static int jffs2_scan_xattr_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 323                                  struct jffs2_raw_xattr *rx, uint32_t ofs,
 324                                  struct jffs2_summary *s)
 325 {
 326         struct jffs2_xattr_datum *xd;
 327         uint32_t xid, version, totlen, crc;
 328         int err;
 329
 330         crc = crc32(0, rx, sizeof(struct jffs2_raw_xattr) - 4);
 331         if (crc != je32_to_cpu(rx->node_crc)) {
 332                 JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
 333                               ofs, je32_to_cpu(rx->node_crc), crc);
 334                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
 335                         return err;
 336                 return 0;
 337         }
 338
 339         xid = je32_to_cpu(rx->xid);
 340         version = je32_to_cpu(rx->version);
 341
 342         totlen = PAD(sizeof(struct jffs2_raw_xattr)
 343                         + rx->name_len + 1 + je16_to_cpu(rx->value_len));
 344         if (totlen != je32_to_cpu(rx->totlen)) {
 345                 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%u\n",
 346                               ofs, je32_to_cpu(rx->totlen), totlen);
 347                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
 348                         return err;
 349                 return 0;
 350         }
 351
 352         xd = jffs2_setup_xattr_datum(c, xid, version);
 353         if (IS_ERR(xd))
 354                 return PTR_ERR(xd);
 355
 356         if (xd->version > version) {
 357                 struct jffs2_raw_node_ref *raw
 358                         = jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, NULL);
 359                 raw->next_in_ino = xd->node->next_in_ino;
 360                 xd->node->next_in_ino = raw;
 361         } else {
 362                 xd->version = version;
 363                 xd->xprefix = rx->xprefix;
 364                 xd->name_len = rx->name_len;
 365                 xd->value_len = je16_to_cpu(rx->value_len);
 366                 xd->data_crc = je32_to_cpu(rx->data_crc);
 367
 368                 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, (void *)xd);
 369         }
 370
 371         if (jffs2_sum_active())
 372                 jffs2_sum_add_xattr_mem(s, rx, ofs - jeb->offset);
 373         dbg_xattr("scaning xdatum at %#08x (xid=%u, version=%u)\n",
 374                   ofs, xd->xid, xd->version);
 375         return 0;
 376 }
 377
 378 static int jffs2_scan_xref_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 379                                 struct jffs2_raw_xref *rr, uint32_t ofs,
 380                                 struct jffs2_summary *s)
 381 {
 382         struct jffs2_xattr_ref *ref;
 383         uint32_t crc;
 384         int err;
 385
 386         crc = crc32(0, rr, sizeof(*rr) - 4);
 387         if (crc != je32_to_cpu(rr->node_crc)) {
 388                 JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
 389                               ofs, je32_to_cpu(rr->node_crc), crc);
 390                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rr->totlen)))))
 391                         return err;
 392                 return 0;
 393         }
 394
 395         if (PAD(sizeof(struct jffs2_raw_xref)) != je32_to_cpu(rr->totlen)) {
 396                 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%zd\n",
 397                               ofs, je32_to_cpu(rr->totlen),
 398                               PAD(sizeof(struct jffs2_raw_xref)));
 399                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rr->totlen))))
 400                         return err;
 401                 return 0;
 402         }
 403
 404         ref = jffs2_alloc_xattr_ref();
 405         if (!ref)
 406                 return -ENOMEM;
 407
 408         /* BEFORE jffs2_build_xattr_subsystem() called,
 409          * and AFTER xattr_ref is marked as a dead xref,
 410          * ref->xid is used to store 32bit xid, xd is not used
 411          * ref->ino is used to store 32bit inode-number, ic is not used
 412          * Thoes variables are declared as union, thus using those
 413          * are exclusive. In a similar way, ref->next is temporarily
 414          * used to chain all xattr_ref object. It's re-chained to
 415          * jffs2_inode_cache in jffs2_build_xattr_subsystem() correctly.
 416          */
 417         ref->ino = je32_to_cpu(rr->ino);
 418         ref->xid = je32_to_cpu(rr->xid);
 419         ref->xseqno = je32_to_cpu(rr->xseqno);
 420         if (ref->xseqno > c->highest_xseqno)
 421                 c->highest_xseqno = (ref->xseqno & ~XREF_DELETE_MARKER);
 422         ref->next = c->xref_temp;
 423         c->xref_temp = ref;
 424
 425         jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(rr->totlen)), (void *)ref);
 426
 427         if (jffs2_sum_active())
 428                 jffs2_sum_add_xref_mem(s, rr, ofs - jeb->offset);
 429         dbg_xattr("scan xref at %#08x (xid=%u, ino=%u)\n",
 430                   ofs, ref->xid, ref->ino);
 431         return 0;
 432 }
 433 #endif
 434
 435 /* Called with 'buf_size == 0' if buf is in fact a pointer _directly_ into
 436    the flash, XIP-style */
 437 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 438                                   unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) {
 439         struct jffs2_unknown_node *node;
 440         struct jffs2_unknown_node crcnode;
 441         uint32_t ofs, prevofs, max_ofs;
 442         uint32_t hdr_crc, buf_ofs, buf_len;
 443         int err;
 444         int noise = 0;
 445
 446
 447 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 448         int cleanmarkerfound = 0;
 449 #endif
 450
 451         ofs = jeb->offset;
 452         prevofs = jeb->offset - 1;
 453
 454         D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs));
 455
 456 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 457         if (jffs2_cleanmarker_oob(c)) {
 458                 int ret;
 459
 460                 if (c->mtd->block_isbad(c->mtd, jeb->offset))
 461                         return BLK_STATE_BADBLOCK;
 462
 463                 ret = jffs2_check_nand_cleanmarker(c, jeb);
 464                 D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n",ret));
 465
 466                 /* Even if it's not found, we still scan to see
 467                    if the block is empty. We use this information
 468                    to decide whether to erase it or not. */
 469                 switch (ret) {
 470                 case 0:         cleanmarkerfound = 1; break;
 471                 case 1:         break;
 472                 default:        return ret;
 473                 }
 474         }
 475 #endif
 476
 477         if (jffs2_sum_active()) {
 478                 struct jffs2_sum_marker *sm;
 479                 void *sumptr = NULL;
 480                 uint32_t sumlen;
 481
 482                 if (!buf_size) {
 483                         /* XIP case. Just look, point at the summary if it's there */
 484                         sm = (void *)buf + c->sector_size - sizeof(*sm);
 485                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
 486                                 sumptr = buf + je32_to_cpu(sm->offset);
 487                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
 488                         }
 489                 } else {
 490                         /* If NAND flash, read a whole page of it. Else just the end */
 491                         if (c->wbuf_pagesize)
 492                                 buf_len = c->wbuf_pagesize;
 493                         else
 494                                 buf_len = sizeof(*sm);
 495
 496                         /* Read as much as we want into the _end_ of the preallocated buffer */
 497                         err = jffs2_fill_scan_buf(c, buf + buf_size - buf_len,
 498                                                   jeb->offset + c->sector_size - buf_len,
 499                                                   buf_len);
 500                         if (err)
 501                                 return err;
 502
 503                         sm = (void *)buf + buf_size - sizeof(*sm);
 504                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
 505                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
 506                                 sumptr = buf + buf_size - sumlen;
 507
 508                                 /* Now, make sure the summary itself is available */
 509                                 if (sumlen > buf_size) {
 510                                         /* Need to kmalloc for this. */
 511                                         sumptr = kmalloc(sumlen, GFP_KERNEL);
 512                                         if (!sumptr)
 513                                                 return -ENOMEM;
 514                                         memcpy(sumptr + sumlen - buf_len, buf + buf_size - buf_len, buf_len);
 515                                 }
 516                                 if (buf_len < sumlen) {
 517                                         /* Need to read more so that the entire summary node is present */
 518                                         err = jffs2_fill_scan_buf(c, sumptr,
 519                                                                   jeb->offset + c->sector_size - sumlen,
 520                                                                   sumlen - buf_len);
 521                                         if (err)
 522                                                 return err;
 523                                 }
 524                         }
 525
 526                 }
 527
 528                 if (sumptr) {
 529                         err = jffs2_sum_scan_sumnode(c, jeb, sumptr, sumlen, &pseudo_random);
 530
 531                         if (buf_size && sumlen > buf_size)
 532                                 kfree(sumptr);
 533                         /* If it returns with a real error, bail.
 534                            If it returns positive, that's a block classification
 535                            (i.e. BLK_STATE_xxx) so return that too.
 536                            If it returns zero, fall through to full scan. */
 537                         if (err)
 538                                 return err;
 539                 }
 540         }
 541
 542         buf_ofs = jeb->offset;
 543
 544         if (!buf_size) {
 545                 /* This is the XIP case -- we're reading _directly_ from the flash chip */
 546                 buf_len = c->sector_size;
 547         } else {
 548                 buf_len = EMPTY_SCAN_SIZE(c->sector_size);
 549                 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
 550                 if (err)
 551                         return err;
 552         }
 553
 554         /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
 555         ofs = 0;
 556         max_ofs = EMPTY_SCAN_SIZE(c->sector_size);
 557         /* Scan only EMPTY_SCAN_SIZE of 0xFF before declaring it's empty */
 558         while(ofs < max_ofs && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
 559                 ofs += 4;
 560
 561         if (ofs == max_ofs) {
 562 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 563                 if (jffs2_cleanmarker_oob(c)) {
 564                         /* scan oob, take care of cleanmarker */
 565                         int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
 566                         D2(printk(KERN_NOTICE "jffs2_check_oob_empty returned %d\n",ret));
 567                         switch (ret) {
 568                         case 0:         return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
 569                         case 1:         return BLK_STATE_ALLDIRTY;
 570                         default:        return ret;
 571                         }
 572                 }
 573 #endif
 574                 D1(printk(KERN_DEBUG "Block at 0x%08x is empty (erased)\n", jeb->offset));
 575                 if (c->cleanmarker_size == 0)
 576                         return BLK_STATE_CLEANMARKER;   /* don't bother with re-erase */
 577                 else
 578                         return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
 579         }
 580         if (ofs) {
 581                 D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset,
 582                           jeb->offset + ofs));
 583                 if ((err = jffs2_prealloc_raw_node_refs(c, jeb, 1)))
 584                         return err;
 585                 if ((err = jffs2_scan_dirty_space(c, jeb, ofs)))
 586                         return err;
 587         }
 588
 589         /* Now ofs is a complete physical flash offset as it always was... */
 590         ofs += jeb->offset;
 591
 592         noise = 10;
 593
 594         dbg_summary("no summary found in jeb 0x%08x. Apply original scan.\n",jeb->offset);
 595
 596 scan_more:
 597         while(ofs < jeb->offset + c->sector_size) {
 598
 599                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 600
 601                 /* Make sure there are node refs available for use */
 602                 err = jffs2_prealloc_raw_node_refs(c, jeb, 2);
 603                 if (err)
 604                         return err;
 605
 606                 cond_resched();
 607
 608                 if (ofs & 3) {
 609                         printk(KERN_WARNING "Eep. ofs 0x%08x not word-aligned!\n", ofs);
 610                         ofs = PAD(ofs);
 611                         continue;
 612                 }
 613                 if (ofs == prevofs) {
 614                         printk(KERN_WARNING "ofs 0x%08x has already been seen. Skipping\n", ofs);
 615                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 616                                 return err;
 617                         ofs += 4;
 618                         continue;
 619                 }
 620                 prevofs = ofs;
 621
 622                 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
 623                         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),
 624                                   jeb->offset, c->sector_size, ofs, sizeof(*node)));
 625                         if ((err = jffs2_scan_dirty_space(c, jeb, (jeb->offset + c->sector_size)-ofs)))
 626                                 return err;
 627                         break;
 628                 }
 629
 630                 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
 631                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 632                         D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
 633                                   sizeof(struct jffs2_unknown_node), buf_len, ofs));
 634                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 635                         if (err)
 636                                 return err;
 637                         buf_ofs = ofs;
 638                 }
 639
 640                 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
 641
 642                 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
 643                         uint32_t inbuf_ofs;
 644                         uint32_t empty_start, scan_end;
 645
 646                         empty_start = ofs;
 647                         ofs += 4;
 648                         scan_end = min_t(uint32_t, EMPTY_SCAN_SIZE(c->sector_size)/8, buf_len);
 649
 650                         D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs));
 651                 more_empty:
 652                         inbuf_ofs = ofs - buf_ofs;
 653                         while (inbuf_ofs < scan_end) {
 654                                 if (unlikely(*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff)) {
 655                                         printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n",
 656                                                empty_start, ofs);
 657                                         if ((err = jffs2_scan_dirty_space(c, jeb, ofs-empty_start)))
 658                                                 return err;
 659                                         goto scan_more;
 660                                 }
 661
 662                                 inbuf_ofs+=4;
 663                                 ofs += 4;
 664                         }
 665                         /* Ran off end. */
 666                         D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs));
 667
 668                         /* If we're only checking the beginning of a block with a cleanmarker,
 669                            bail now */
 670                         if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&
 671                             c->cleanmarker_size && !jeb->dirty_size && !ref_next(jeb->first_node)) {
 672                                 D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE(c->sector_size)));
 673                                 return BLK_STATE_CLEANMARKER;
 674                         }
 675                         if (!buf_size && (scan_end != buf_len)) {/* XIP/point case */
 676                                 scan_end = buf_len;
 677                                 goto more_empty;
 678                         }
 679
 680                         /* See how much more there is to read in this eraseblock... */
 681                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 682                         if (!buf_len) {
 683                                 /* No more to read. Break out of main loop without marking
 684                                    this range of empty space as dirty (because it's not) */
 685                                 D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block. Treating as free_space\n",
 686                                           empty_start));
 687                                 break;
 688                         }
 689                         /* point never reaches here */
 690                         scan_end = buf_len;
 691                         D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs));
 692                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 693                         if (err)
 694                                 return err;
 695                         buf_ofs = ofs;
 696                         goto more_empty;
 697                 }
 698
 699                 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
 700                         printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n", ofs);
 701                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 702                                 return err;
 703                         ofs += 4;
 704                         continue;
 705                 }
 706                 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
 707                         D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs));
 708                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 709                                 return err;
 710                         ofs += 4;
 711                         continue;
 712                 }
 713                 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
 714                         printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08x\n", ofs);
 715                         printk(KERN_WARNING "You cannot use older JFFS2 filesystems with newer kernels\n");
 716                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 717                                 return err;
 718                         ofs += 4;
 719                         continue;
 720                 }
 721                 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
 722                         /* OK. We're out of possibilities. Whinge and move on */
 723                         noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n",
 724                                      JFFS2_MAGIC_BITMASK, ofs,
 725                                      je16_to_cpu(node->magic));
 726                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 727                                 return err;
 728                         ofs += 4;
 729                         continue;
 730                 }
 731                 /* We seem to have a node of sorts. Check the CRC */
 732                 crcnode.magic = node->magic;
 733                 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
 734                 crcnode.totlen = node->totlen;
 735                 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
 736
 737                 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
 738                         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",
 739                                      ofs, je16_to_cpu(node->magic),
 740                                      je16_to_cpu(node->nodetype),
 741                                      je32_to_cpu(node->totlen),
 742                                      je32_to_cpu(node->hdr_crc),
 743                                      hdr_crc);
 744                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 745                                 return err;
 746                         ofs += 4;
 747                         continue;
 748                 }
 749
 750                 if (ofs + je32_to_cpu(node->totlen) > jeb->offset + c->sector_size) {
 751                         /* Eep. Node goes over the end of the erase block. */
 752                         printk(KERN_WARNING "Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
 753                                ofs, je32_to_cpu(node->totlen));
 754                         printk(KERN_WARNING "Perhaps the file system was created with the wrong erase size?\n");
 755                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 756                                 return err;
 757                         ofs += 4;
 758                         continue;
 759                 }
 760
 761                 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
 762                         /* Wheee. This is an obsoleted node */
 763                         D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs));
 764                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 765                                 return err;
 766                         ofs += PAD(je32_to_cpu(node->totlen));
 767                         continue;
 768                 }
 769
 770                 switch(je16_to_cpu(node->nodetype)) {
 771                 case JFFS2_NODETYPE_INODE:
 772                         if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
 773                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 774                                 D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
 775                                           sizeof(struct jffs2_raw_inode), buf_len, ofs));
 776                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 777                                 if (err)
 778                                         return err;
 779                                 buf_ofs = ofs;
 780                                 node = (void *)buf;
 781                         }
 782                         err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs, s);
 783                         if (err) return err;
 784                         ofs += PAD(je32_to_cpu(node->totlen));
 785                         break;
 786
 787                 case JFFS2_NODETYPE_DIRENT:
 788                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 789                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 790                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
 791                                           je32_to_cpu(node->totlen), buf_len, ofs));
 792                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 793                                 if (err)
 794                                         return err;
 795                                 buf_ofs = ofs;
 796                                 node = (void *)buf;
 797                         }
 798                         err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs, s);
 799                         if (err) return err;
 800                         ofs += PAD(je32_to_cpu(node->totlen));
 801                         break;
 802
 803 #ifdef CONFIG_JFFS2_FS_XATTR
 804                 case JFFS2_NODETYPE_XATTR:
 805                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 806                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 807                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (xattr node)"
 808                                           " left to end of buf. Reading 0x%x at 0x%08x\n",
 809                                           je32_to_cpu(node->totlen), buf_len, ofs));
 810                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 811                                 if (err)
 812                                         return err;
 813                                 buf_ofs = ofs;
 814                                 node = (void *)buf;
 815                         }
 816                         err = jffs2_scan_xattr_node(c, jeb, (void *)node, ofs, s);
 817                         if (err)
 818                                 return err;
 819                         ofs += PAD(je32_to_cpu(node->totlen));
 820                         break;
 821                 case JFFS2_NODETYPE_XREF:
 822                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 823                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 824                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (xref node)"
 825                                           " left to end of buf. Reading 0x%x at 0x%08x\n",
 826                                           je32_to_cpu(node->totlen), buf_len, ofs));
 827                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 828                                 if (err)
 829                                         return err;
 830                                 buf_ofs = ofs;
 831                                 node = (void *)buf;
 832                         }
 833                         err = jffs2_scan_xref_node(c, jeb, (void *)node, ofs, s);
 834                         if (err)
 835                                 return err;
 836                         ofs += PAD(je32_to_cpu(node->totlen));
 837                         break;
 838 #endif  /* CONFIG_JFFS2_FS_XATTR */
 839
 840                 case JFFS2_NODETYPE_CLEANMARKER:
 841                         D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs));
 842                         if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
 843                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n",
 844                                        ofs, je32_to_cpu(node->totlen), c->cleanmarker_size);
 845                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
 846                                         return err;
 847                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 848                         } else if (jeb->first_node) {
 849                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n", ofs, jeb->offset);
 850                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
 851                                         return err;
 852                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 853                         } else {
 854                                 jffs2_link_node_ref(c, jeb, ofs | REF_NORMAL, c->cleanmarker_size, NULL);
 855
 856                                 ofs += PAD(c->cleanmarker_size);
 857                         }
 858                         break;
 859
 860                 case JFFS2_NODETYPE_PADDING:
 861                         if (jffs2_sum_active())
 862                                 jffs2_sum_add_padding_mem(s, je32_to_cpu(node->totlen));
 863                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 864                                 return err;
 865                         ofs += PAD(je32_to_cpu(node->totlen));
 866                         break;
 867
 868                 default:
 869                         switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
 870                         case JFFS2_FEATURE_ROCOMPAT:
 871                                 printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 872                                 c->flags |= JFFS2_SB_FLAG_RO;
 873                                 if (!(jffs2_is_readonly(c)))
 874                                         return -EROFS;
 875                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 876                                         return err;
 877                                 ofs += PAD(je32_to_cpu(node->totlen));
 878                                 break;
 879
 880                         case JFFS2_FEATURE_INCOMPAT:
 881                                 printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 882                                 return -EINVAL;
 883
 884                         case JFFS2_FEATURE_RWCOMPAT_DELETE:
 885                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 886                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 887                                         return err;
 888                                 ofs += PAD(je32_to_cpu(node->totlen));
 889                                 break;
 890
 891                         case JFFS2_FEATURE_RWCOMPAT_COPY: {
 892                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 893
 894                                 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(node->totlen)), NULL);
 895
 896                                 /* We can't summarise nodes we don't grok */
 897                                 jffs2_sum_disable_collecting(s);
 898                                 ofs += PAD(je32_to_cpu(node->totlen));
 899                                 break;
 900                                 }
 901                         }
 902                 }
 903         }
 904
 905         if (jffs2_sum_active()) {
 906                 if (PAD(s->sum_size + JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size) {
 907                         dbg_summary("There is not enough space for "
 908                                 "summary information, disabling for this jeb!\n");
 909                         jffs2_sum_disable_collecting(s);
 910                 }
 911         }
 912
 913         D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x, wasted 0x%08x\n",
 914                   jeb->offset,jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size, jeb->wasted_size));
 915
 916         /* mark_node_obsolete can add to wasted !! */
 917         if (jeb->wasted_size) {
 918                 jeb->dirty_size += jeb->wasted_size;
 919                 c->dirty_size += jeb->wasted_size;
 920                 c->wasted_size -= jeb->wasted_size;
 921                 jeb->wasted_size = 0;
 922         }
 923
 924         return jffs2_scan_classify_jeb(c, jeb);
 925 }
 926
 927 struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
 928 {
 929         struct jffs2_inode_cache *ic;
 930
 931         ic = jffs2_get_ino_cache(c, ino);
 932         if (ic)
 933                 return ic;
 934
 935         if (ino > c->highest_ino)
 936                 c->highest_ino = ino;
 937
 938         ic = jffs2_alloc_inode_cache();
 939         if (!ic) {
 940                 printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n");
 941                 return NULL;
 942         }
 943         memset(ic, 0, sizeof(*ic));
 944
 945         ic->ino = ino;
 946         ic->nodes = (void *)ic;
 947         jffs2_add_ino_cache(c, ic);
 948         if (ino == 1)
 949                 ic->pino_nlink = 1;
 950         return ic;
 951 }
 952
 953 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 954                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s)
 955 {
 956         struct jffs2_inode_cache *ic;
 957         uint32_t crc, ino = je32_to_cpu(ri->ino);
 958
 959         D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs));
 960
 961         /* We do very little here now. Just check the ino# to which we should attribute
 962            this node; we can do all the CRC checking etc. later. There's a tradeoff here --
 963            we used to scan the flash once only, reading everything we want from it into
 964            memory, then building all our in-core data structures and freeing the extra
 965            information. Now we allow the first part of the mount to complete a lot quicker,
 966            but we have to go _back_ to the flash in order to finish the CRC checking, etc.
 967            Which means that the _full_ amount of time to get to proper write mode with GC
 968            operational may actually be _longer_ than before. Sucks to be me. */
 969
 970         /* Check the node CRC in any case. */
 971         crc = crc32(0, ri, sizeof(*ri)-8);
 972         if (crc != je32_to_cpu(ri->node_crc)) {
 973                 printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on "
 974                        "node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 975                        ofs, je32_to_cpu(ri->node_crc), crc);
 976                 /*
 977                  * We believe totlen because the CRC on the node
 978                  * _header_ was OK, just the node itself failed.
 979                  */
 980                 return jffs2_scan_dirty_space(c, jeb,
 981                                               PAD(je32_to_cpu(ri->totlen)));
 982         }
 983
 984         ic = jffs2_get_ino_cache(c, ino);
 985         if (!ic) {
 986                 ic = jffs2_scan_make_ino_cache(c, ino);
 987                 if (!ic)
 988                         return -ENOMEM;
 989         }
 990
 991         /* Wheee. It worked */
 992         jffs2_link_node_ref(c, jeb, ofs | REF_UNCHECKED, PAD(je32_to_cpu(ri->totlen)), ic);
 993
 994         D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
 995                   je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
 996                   je32_to_cpu(ri->offset),
 997                   je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize)));
 998
 999         pseudo_random += je32_to_cpu(ri->version);
1000
1001         if (jffs2_sum_active()) {
1002                 jffs2_sum_add_inode_mem(s, ri, ofs - jeb->offset);
1003         }
1004
1005         return 0;
1006 }
1007
1008 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
1009                                   struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s)
1010 {
1011         struct jffs2_full_dirent *fd;
1012         struct jffs2_inode_cache *ic;
1013         uint32_t checkedlen;
1014         uint32_t crc;
1015         int err;
1016
1017         D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs));
1018
1019         /* We don't get here unless the node is still valid, so we don't have to
1020            mask in the ACCURATE bit any more. */
1021         crc = crc32(0, rd, sizeof(*rd)-8);
1022
1023         if (crc != je32_to_cpu(rd->node_crc)) {
1024                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1025                        ofs, je32_to_cpu(rd->node_crc), crc);
1026                 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
1027                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1028                         return err;
1029                 return 0;
1030         }
1031
1032         pseudo_random += je32_to_cpu(rd->version);
1033
1034         /* Should never happen. Did. (OLPC trac #4184)*/
1035         checkedlen = strnlen(rd->name, rd->nsize);
1036         if (checkedlen < rd->nsize) {
1037                 printk(KERN_ERR "Dirent at %08x has zeroes in name. Truncating to %d chars\n",
1038                        ofs, checkedlen);
1039         }
1040         fd = jffs2_alloc_full_dirent(checkedlen+1);
1041         if (!fd) {
1042                 return -ENOMEM;
1043         }
1044         memcpy(&fd->name, rd->name, checkedlen);
1045         fd->name[checkedlen] = 0;
1046
1047         crc = crc32(0, fd->name, rd->nsize);
1048         if (crc != je32_to_cpu(rd->name_crc)) {
1049                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1050                        ofs, je32_to_cpu(rd->name_crc), crc);
1051                 D1(printk(KERN_NOTICE "Name for which CRC failed is (now) '%s', ino #%d\n", fd->name, je32_to_cpu(rd->ino)));
1052                 jffs2_free_full_dirent(fd);
1053                 /* FIXME: Why do we believe totlen? */
1054                 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
1055                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1056                         return err;
1057                 return 0;
1058         }
1059         ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
1060         if (!ic) {
1061                 jffs2_free_full_dirent(fd);
1062                 return -ENOMEM;
1063         }
1064
1065         fd->raw = jffs2_link_node_ref(c, jeb, ofs | dirent_node_state(rd),
1066                                       PAD(je32_to_cpu(rd->totlen)), ic);
1067
1068         fd->next = NULL;
1069         fd->version = je32_to_cpu(rd->version);
1070         fd->ino = je32_to_cpu(rd->ino);
1071         fd->nhash = full_name_hash(fd->name, checkedlen);
1072         fd->type = rd->type;
1073         jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
1074
1075         if (jffs2_sum_active()) {
1076                 jffs2_sum_add_dirent_mem(s, rd, ofs - jeb->offset);
1077         }
1078
1079         return 0;
1080 }
1081
1082 static int count_list(struct list_head *l)
1083 {
1084         uint32_t count = 0;
1085         struct list_head *tmp;
1086
1087         list_for_each(tmp, l) {
1088                 count++;
1089         }
1090         return count;
1091 }
1092
1093 /* Note: This breaks if list_empty(head). I don't care. You
1094    might, if you copy this code and use it elsewhere :) */
1095 static void rotate_list(struct list_head *head, uint32_t count)
1096 {
1097         struct list_head *n = head->next;
1098
1099         list_del(head);
1100         while(count--) {
1101                 n = n->next;
1102         }
1103         list_add(head, n);
1104 }
1105
1106 void jffs2_rotate_lists(struct jffs2_sb_info *c)
1107 {
1108         uint32_t x;
1109         uint32_t rotateby;
1110
1111         x = count_list(&c->clean_list);
1112         if (x) {
1113                 rotateby = pseudo_random % x;
1114                 rotate_list((&c->clean_list), rotateby);
1115         }
1116
1117         x = count_list(&c->very_dirty_list);
1118         if (x) {
1119                 rotateby = pseudo_random % x;
1120                 rotate_list((&c->very_dirty_list), rotateby);
1121         }
1122
1123         x = count_list(&c->dirty_list);
1124         if (x) {
1125                 rotateby = pseudo_random % x;
1126                 rotate_list((&c->dirty_list), rotateby);
1127         }
1128
1129         x = count_list(&c->erasable_list);
1130         if (x) {
1131                 rotateby = pseudo_random % x;
1132                 rotate_list((&c->erasable_list), rotateby);
1133         }
1134
1135         if (c->nr_erasing_blocks) {
1136                 rotateby = pseudo_random % c->nr_erasing_blocks;
1137                 rotate_list((&c->erase_pending_list), rotateby);
1138         }
1139
1140         if (c->nr_free_blocks) {
1141                 rotateby = pseudo_random % c->nr_free_blocks;
1142                 rotate_list((&c->free_list), rotateby);
1143         }
1144 }