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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/kernel.h>
  15 #include <linux/sched.h>
  16 #include <linux/slab.h>
  17 #include <linux/mtd/mtd.h>
  18 #include <linux/pagemap.h>
  19 #include <linux/crc32.h>
  20 #include <linux/compiler.h>
  21 #include "nodelist.h"
  22 #include "summary.h"
  23 #include "debug.h"
  24
  25 #define DEFAULT_EMPTY_SCAN_SIZE 256
  26
  27 #define noisy_printk(noise, fmt, ...)                                   \
  28 do {                                                                    \
  29         if (*(noise)) {                                                 \
  30                 pr_notice(fmt, ##__VA_ARGS__);                          \
  31                 (*(noise))--;                                           \
  32                 if (!(*(noise)))                                        \
  33                         pr_notice("Further such events for this erase block will not be printed\n"); \
  34         }                                                               \
  35 } while (0)
  36
  37 static uint32_t pseudo_random;
  38
  39 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  40                                   unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s);
  41
  42 /* These helper functions _must_ increase ofs and also do the dirty/used space accounting.
  43  * Returning an error will abort the mount - bad checksums etc. should just mark the space
  44  * as dirty.
  45  */
  46 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  47                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s);
  48 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  49                                  struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s);
  50
  51 static inline int min_free(struct jffs2_sb_info *c)
  52 {
  53         uint32_t min = 2 * sizeof(struct jffs2_raw_inode);
  54 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
  55         if (!jffs2_can_mark_obsolete(c) && min < c->wbuf_pagesize)
  56                 return c->wbuf_pagesize;
  57 #endif
  58         return min;
  59
  60 }
  61
  62 static inline uint32_t EMPTY_SCAN_SIZE(uint32_t sector_size) {
  63         if (sector_size < DEFAULT_EMPTY_SCAN_SIZE)
  64                 return sector_size;
  65         else
  66                 return DEFAULT_EMPTY_SCAN_SIZE;
  67 }
  68
  69 static int file_dirty(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
  70 {
  71         int ret;
  72
  73         if ((ret = jffs2_prealloc_raw_node_refs(c, jeb, 1)))
  74                 return ret;
  75         if ((ret = jffs2_scan_dirty_space(c, jeb, jeb->free_size)))
  76                 return ret;
  77         /* Turned wasted size into dirty, since we apparently
  78            think it's recoverable now. */
  79         jeb->dirty_size += jeb->wasted_size;
  80         c->dirty_size += jeb->wasted_size;
  81         c->wasted_size -= jeb->wasted_size;
  82         jeb->wasted_size = 0;
  83         if (VERYDIRTY(c, jeb->dirty_size)) {
  84                 list_add(&jeb->list, &c->very_dirty_list);
  85         } else {
  86                 list_add(&jeb->list, &c->dirty_list);
  87         }
  88         return 0;
  89 }
  90
  91 int jffs2_scan_medium(struct jffs2_sb_info *c)
  92 {
  93         int i, ret;
  94         uint32_t empty_blocks = 0, bad_blocks = 0;
  95         unsigned char *flashbuf = NULL;
  96         uint32_t buf_size = 0;
  97         struct jffs2_summary *s = NULL; /* summary info collected by the scan process */
  98 #ifndef __ECOS
  99         size_t pointlen, try_size;
 100
 101         ret = mtd_point(c->mtd, 0, c->mtd->size, &pointlen,
 102                         (void **)&flashbuf, NULL);
 103         if (!ret && pointlen < c->mtd->size) {
 104                 /* Don't muck about if it won't let us point to the whole flash */
 105                 jffs2_dbg(1, "MTD point returned len too short: 0x%zx\n",
 106                           pointlen);
 107                 mtd_unpoint(c->mtd, 0, pointlen);
 108                 flashbuf = NULL;
 109         }
 110         if (ret && ret != -EOPNOTSUPP)
 111                 jffs2_dbg(1, "MTD point failed %d\n", ret);
 112 #endif
 113         if (!flashbuf) {
 114                 /* For NAND it's quicker to read a whole eraseblock at a time,
 115                    apparently */
 116                 if (jffs2_cleanmarker_oob(c))
 117                         try_size = c->sector_size;
 118                 else
 119                         try_size = PAGE_SIZE;
 120
 121                 jffs2_dbg(1, "Trying to allocate readbuf of %zu "
 122                           "bytes\n", try_size);
 123
 124                 flashbuf = mtd_kmalloc_up_to(c->mtd, &try_size);
 125                 if (!flashbuf)
 126                         return -ENOMEM;
 127
 128                 jffs2_dbg(1, "Allocated readbuf of %zu bytes\n",
 129                           try_size);
 130
 131                 buf_size = (uint32_t)try_size;
 132         }
 133
 134         if (jffs2_sum_active()) {
 135                 s = kzalloc(sizeof(struct jffs2_summary), GFP_KERNEL);
 136                 if (!s) {
 137                         JFFS2_WARNING("Can't allocate memory for summary\n");
 138                         ret = -ENOMEM;
 139                         goto out;
 140                 }
 141         }
 142
 143         for (i=0; i<c->nr_blocks; i++) {
 144                 struct jffs2_eraseblock *jeb = &c->blocks[i];
 145
 146                 cond_resched();
 147
 148                 /* reset summary info for next eraseblock scan */
 149                 jffs2_sum_reset_collected(s);
 150
 151                 ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset),
 152                                                 buf_size, s);
 153
 154                 if (ret < 0)
 155                         goto out;
 156
 157                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 158
 159                 /* Now decide which list to put it on */
 160                 switch(ret) {
 161                 case BLK_STATE_ALLFF:
 162                         /*
 163                          * Empty block.   Since we can't be sure it
 164                          * was entirely erased, we just queue it for erase
 165                          * again.  It will be marked as such when the erase
 166                          * is complete.  Meanwhile we still count it as empty
 167                          * for later checks.
 168                          */
 169                         empty_blocks++;
 170                         list_add(&jeb->list, &c->erase_pending_list);
 171                         c->nr_erasing_blocks++;
 172                         break;
 173
 174                 case BLK_STATE_CLEANMARKER:
 175                         /* Only a CLEANMARKER node is valid */
 176                         if (!jeb->dirty_size) {
 177                                 /* It's actually free */
 178                                 list_add(&jeb->list, &c->free_list);
 179                                 c->nr_free_blocks++;
 180                         } else {
 181                                 /* Dirt */
 182                                 jffs2_dbg(1, "Adding all-dirty block at 0x%08x to erase_pending_list\n",
 183                                           jeb->offset);
 184                                 list_add(&jeb->list, &c->erase_pending_list);
 185                                 c->nr_erasing_blocks++;
 186                         }
 187                         break;
 188
 189                 case BLK_STATE_CLEAN:
 190                         /* Full (or almost full) of clean data. Clean list */
 191                         list_add(&jeb->list, &c->clean_list);
 192                         break;
 193
 194                 case BLK_STATE_PARTDIRTY:
 195                         /* Some data, but not full. Dirty list. */
 196                         /* We want to remember the block with most free space
 197                         and stick it in the 'nextblock' position to start writing to it. */
 198                         if (jeb->free_size > min_free(c) &&
 199                                         (!c->nextblock || c->nextblock->free_size < jeb->free_size)) {
 200                                 /* Better candidate for the next writes to go to */
 201                                 if (c->nextblock) {
 202                                         ret = file_dirty(c, c->nextblock);
 203                                         if (ret)
 204                                                 goto out;
 205                                         /* deleting summary information of the old nextblock */
 206                                         jffs2_sum_reset_collected(c->summary);
 207                                 }
 208                                 /* update collected summary information for the current nextblock */
 209                                 jffs2_sum_move_collected(c, s);
 210                                 jffs2_dbg(1, "%s(): new nextblock = 0x%08x\n",
 211                                           __func__, jeb->offset);
 212                                 c->nextblock = jeb;
 213                         } else {
 214                                 ret = file_dirty(c, jeb);
 215                                 if (ret)
 216                                         goto out;
 217                         }
 218                         break;
 219
 220                 case BLK_STATE_ALLDIRTY:
 221                         /* Nothing valid - not even a clean marker. Needs erasing. */
 222                         /* For now we just put it on the erasing list. We'll start the erases later */
 223                         jffs2_dbg(1, "Erase block at 0x%08x is not formatted. It will be erased\n",
 224                                   jeb->offset);
 225                         list_add(&jeb->list, &c->erase_pending_list);
 226                         c->nr_erasing_blocks++;
 227                         break;
 228
 229                 case BLK_STATE_BADBLOCK:
 230                         jffs2_dbg(1, "Block at 0x%08x is bad\n", jeb->offset);
 231                         list_add(&jeb->list, &c->bad_list);
 232                         c->bad_size += c->sector_size;
 233                         c->free_size -= c->sector_size;
 234                         bad_blocks++;
 235                         break;
 236                 default:
 237                         pr_warn("%s(): unknown block state\n", __func__);
 238                         BUG();
 239                 }
 240         }
 241
 242         /* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
 243         if (c->nextblock && (c->nextblock->dirty_size)) {
 244                 c->nextblock->wasted_size += c->nextblock->dirty_size;
 245                 c->wasted_size += c->nextblock->dirty_size;
 246                 c->dirty_size -= c->nextblock->dirty_size;
 247                 c->nextblock->dirty_size = 0;
 248         }
 249 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 250         if (!jffs2_can_mark_obsolete(c) && c->wbuf_pagesize && c->nextblock && (c->nextblock->free_size % c->wbuf_pagesize)) {
 251                 /* If we're going to start writing into a block which already
 252                    contains data, and the end of the data isn't page-aligned,
 253                    skip a little and align it. */
 254
 255                 uint32_t skip = c->nextblock->free_size % c->wbuf_pagesize;
 256
 257                 jffs2_dbg(1, "%s(): Skipping %d bytes in nextblock to ensure page alignment\n",
 258                           __func__, skip);
 259                 jffs2_prealloc_raw_node_refs(c, c->nextblock, 1);
 260                 jffs2_scan_dirty_space(c, c->nextblock, skip);
 261         }
 262 #endif
 263         if (c->nr_erasing_blocks) {
 264                 if (!c->used_size && !c->unchecked_size &&
 265                         ((c->nr_free_blocks+empty_blocks+bad_blocks) != c->nr_blocks || bad_blocks == c->nr_blocks)) {
 266                         pr_notice("Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
 267                         pr_notice("empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",
 268                                   empty_blocks, bad_blocks, c->nr_blocks);
 269                         ret = -EIO;
 270                         goto out;
 271                 }
 272                 spin_lock(&c->erase_completion_lock);
 273                 jffs2_garbage_collect_trigger(c);
 274                 spin_unlock(&c->erase_completion_lock);
 275         }
 276         ret = 0;
 277  out:
 278         if (buf_size)
 279                 kfree(flashbuf);
 280 #ifndef __ECOS
 281         else
 282                 mtd_unpoint(c->mtd, 0, c->mtd->size);
 283 #endif
 284         kfree(s);
 285         return ret;
 286 }
 287
 288 static int jffs2_fill_scan_buf(struct jffs2_sb_info *c, void *buf,
 289                                uint32_t ofs, uint32_t len)
 290 {
 291         int ret;
 292         size_t retlen;
 293
 294         ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
 295         if (ret) {
 296                 jffs2_dbg(1, "mtd->read(0x%x bytes from 0x%x) returned %d\n",
 297                           len, ofs, ret);
 298                 return ret;
 299         }
 300         if (retlen < len) {
 301                 jffs2_dbg(1, "Read at 0x%x gave only 0x%zx bytes\n",
 302                           ofs, retlen);
 303                 return -EIO;
 304         }
 305         return 0;
 306 }
 307
 308 int jffs2_scan_classify_jeb(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
 309 {
 310         if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size
 311             && (!jeb->first_node || !ref_next(jeb->first_node)) )
 312                 return BLK_STATE_CLEANMARKER;
 313
 314         /* move blocks with max 4 byte dirty space to cleanlist */
 315         else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
 316                 c->dirty_size -= jeb->dirty_size;
 317                 c->wasted_size += jeb->dirty_size;
 318                 jeb->wasted_size += jeb->dirty_size;
 319                 jeb->dirty_size = 0;
 320                 return BLK_STATE_CLEAN;
 321         } else if (jeb->used_size || jeb->unchecked_size)
 322                 return BLK_STATE_PARTDIRTY;
 323         else
 324                 return BLK_STATE_ALLDIRTY;
 325 }
 326
 327 #ifdef CONFIG_JFFS2_FS_XATTR
 328 static int jffs2_scan_xattr_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 329                                  struct jffs2_raw_xattr *rx, uint32_t ofs,
 330                                  struct jffs2_summary *s)
 331 {
 332         struct jffs2_xattr_datum *xd;
 333         uint32_t xid, version, totlen, crc;
 334         int err;
 335
 336         crc = crc32(0, rx, sizeof(struct jffs2_raw_xattr) - 4);
 337         if (crc != je32_to_cpu(rx->node_crc)) {
 338                 JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
 339                               ofs, je32_to_cpu(rx->node_crc), crc);
 340                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
 341                         return err;
 342                 return 0;
 343         }
 344
 345         xid = je32_to_cpu(rx->xid);
 346         version = je32_to_cpu(rx->version);
 347
 348         totlen = PAD(sizeof(struct jffs2_raw_xattr)
 349                         + rx->name_len + 1 + je16_to_cpu(rx->value_len));
 350         if (totlen != je32_to_cpu(rx->totlen)) {
 351                 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%u\n",
 352                               ofs, je32_to_cpu(rx->totlen), totlen);
 353                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
 354                         return err;
 355                 return 0;
 356         }
 357
 358         xd = jffs2_setup_xattr_datum(c, xid, version);
 359         if (IS_ERR(xd))
 360                 return PTR_ERR(xd);
 361
 362         if (xd->version > version) {
 363                 struct jffs2_raw_node_ref *raw
 364                         = jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, NULL);
 365                 raw->next_in_ino = xd->node->next_in_ino;
 366                 xd->node->next_in_ino = raw;
 367         } else {
 368                 xd->version = version;
 369                 xd->xprefix = rx->xprefix;
 370                 xd->name_len = rx->name_len;
 371                 xd->value_len = je16_to_cpu(rx->value_len);
 372                 xd->data_crc = je32_to_cpu(rx->data_crc);
 373
 374                 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, (void *)xd);
 375         }
 376
 377         if (jffs2_sum_active())
 378                 jffs2_sum_add_xattr_mem(s, rx, ofs - jeb->offset);
 379         dbg_xattr("scanning xdatum at %#08x (xid=%u, version=%u)\n",
 380                   ofs, xd->xid, xd->version);
 381         return 0;
 382 }
 383
 384 static int jffs2_scan_xref_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 385                                 struct jffs2_raw_xref *rr, uint32_t ofs,
 386                                 struct jffs2_summary *s)
 387 {
 388         struct jffs2_xattr_ref *ref;
 389         uint32_t crc;
 390         int err;
 391
 392         crc = crc32(0, rr, sizeof(*rr) - 4);
 393         if (crc != je32_to_cpu(rr->node_crc)) {
 394                 JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
 395                               ofs, je32_to_cpu(rr->node_crc), crc);
 396                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rr->totlen)))))
 397                         return err;
 398                 return 0;
 399         }
 400
 401         if (PAD(sizeof(struct jffs2_raw_xref)) != je32_to_cpu(rr->totlen)) {
 402                 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%zd\n",
 403                               ofs, je32_to_cpu(rr->totlen),
 404                               PAD(sizeof(struct jffs2_raw_xref)));
 405                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rr->totlen))))
 406                         return err;
 407                 return 0;
 408         }
 409
 410         ref = jffs2_alloc_xattr_ref();
 411         if (!ref)
 412                 return -ENOMEM;
 413
 414         /* BEFORE jffs2_build_xattr_subsystem() called,
 415          * and AFTER xattr_ref is marked as a dead xref,
 416          * ref->xid is used to store 32bit xid, xd is not used
 417          * ref->ino is used to store 32bit inode-number, ic is not used
 418          * Thoes variables are declared as union, thus using those
 419          * are exclusive. In a similar way, ref->next is temporarily
 420          * used to chain all xattr_ref object. It's re-chained to
 421          * jffs2_inode_cache in jffs2_build_xattr_subsystem() correctly.
 422          */
 423         ref->ino = je32_to_cpu(rr->ino);
 424         ref->xid = je32_to_cpu(rr->xid);
 425         ref->xseqno = je32_to_cpu(rr->xseqno);
 426         if (ref->xseqno > c->highest_xseqno)
 427                 c->highest_xseqno = (ref->xseqno & ~XREF_DELETE_MARKER);
 428         ref->next = c->xref_temp;
 429         c->xref_temp = ref;
 430
 431         jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(rr->totlen)), (void *)ref);
 432
 433         if (jffs2_sum_active())
 434                 jffs2_sum_add_xref_mem(s, rr, ofs - jeb->offset);
 435         dbg_xattr("scan xref at %#08x (xid=%u, ino=%u)\n",
 436                   ofs, ref->xid, ref->ino);
 437         return 0;
 438 }
 439 #endif
 440
 441 /* Called with 'buf_size == 0' if buf is in fact a pointer _directly_ into
 442    the flash, XIP-style */
 443 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 444                                   unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) {
 445         struct jffs2_unknown_node *node;
 446         struct jffs2_unknown_node crcnode;
 447         uint32_t ofs, prevofs, max_ofs;
 448         uint32_t hdr_crc, buf_ofs, buf_len;
 449         int err;
 450         int noise = 0;
 451
 452
 453 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 454         int cleanmarkerfound = 0;
 455 #endif
 456
 457         ofs = jeb->offset;
 458         prevofs = jeb->offset - 1;
 459
 460         jffs2_dbg(1, "%s(): Scanning block at 0x%x\n", __func__, ofs);
 461
 462 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 463         if (jffs2_cleanmarker_oob(c)) {
 464                 int ret;
 465
 466                 if (mtd_block_isbad(c->mtd, jeb->offset))
 467                         return BLK_STATE_BADBLOCK;
 468
 469                 ret = jffs2_check_nand_cleanmarker(c, jeb);
 470                 jffs2_dbg(2, "jffs_check_nand_cleanmarker returned %d\n", ret);
 471
 472                 /* Even if it's not found, we still scan to see
 473                    if the block is empty. We use this information
 474                    to decide whether to erase it or not. */
 475                 switch (ret) {
 476                 case 0:         cleanmarkerfound = 1; break;
 477                 case 1:         break;
 478                 default:        return ret;
 479                 }
 480         }
 481 #endif
 482
 483         if (jffs2_sum_active()) {
 484                 struct jffs2_sum_marker *sm;
 485                 void *sumptr = NULL;
 486                 uint32_t sumlen;
 487
 488                 if (!buf_size) {
 489                         /* XIP case. Just look, point at the summary if it's there */
 490                         sm = (void *)buf + c->sector_size - sizeof(*sm);
 491                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
 492                                 sumptr = buf + je32_to_cpu(sm->offset);
 493                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
 494                         }
 495                 } else {
 496                         /* If NAND flash, read a whole page of it. Else just the end */
 497                         if (c->wbuf_pagesize)
 498                                 buf_len = c->wbuf_pagesize;
 499                         else
 500                                 buf_len = sizeof(*sm);
 501
 502                         /* Read as much as we want into the _end_ of the preallocated buffer */
 503                         err = jffs2_fill_scan_buf(c, buf + buf_size - buf_len,
 504                                                   jeb->offset + c->sector_size - buf_len,
 505                                                   buf_len);
 506                         if (err)
 507                                 return err;
 508
 509                         sm = (void *)buf + buf_size - sizeof(*sm);
 510                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
 511                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
 512                                 sumptr = buf + buf_size - sumlen;
 513
 514                                 /* sm->offset maybe wrong but MAGIC maybe right */
 515                                 if (sumlen > c->sector_size)
 516                                         goto full_scan;
 517
 518                                 /* Now, make sure the summary itself is available */
 519                                 if (sumlen > buf_size) {
 520                                         /* Need to kmalloc for this. */
 521                                         sumptr = kmalloc(sumlen, GFP_KERNEL);
 522                                         if (!sumptr)
 523                                                 return -ENOMEM;
 524                                         memcpy(sumptr + sumlen - buf_len, buf + buf_size - buf_len, buf_len);
 525                                 }
 526                                 if (buf_len < sumlen) {
 527                                         /* Need to read more so that the entire summary node is present */
 528                                         err = jffs2_fill_scan_buf(c, sumptr,
 529                                                                   jeb->offset + c->sector_size - sumlen,
 530                                                                   sumlen - buf_len);
 531                                         if (err) {
 532                                                 if (sumlen > buf_size)
 533                                                         kfree(sumptr);
 534                                                 return err;
 535                                         }
 536                                 }
 537                         }
 538
 539                 }
 540
 541                 if (sumptr) {
 542                         err = jffs2_sum_scan_sumnode(c, jeb, sumptr, sumlen, &pseudo_random);
 543
 544                         if (buf_size && sumlen > buf_size)
 545                                 kfree(sumptr);
 546                         /* If it returns with a real error, bail.
 547                            If it returns positive, that's a block classification
 548                            (i.e. BLK_STATE_xxx) so return that too.
 549                            If it returns zero, fall through to full scan. */
 550                         if (err)
 551                                 return err;
 552                 }
 553         }
 554
 555 full_scan:
 556         buf_ofs = jeb->offset;
 557
 558         if (!buf_size) {
 559                 /* This is the XIP case -- we're reading _directly_ from the flash chip */
 560                 buf_len = c->sector_size;
 561         } else {
 562                 buf_len = EMPTY_SCAN_SIZE(c->sector_size);
 563                 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
 564                 if (err)
 565                         return err;
 566         }
 567
 568         /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
 569         ofs = 0;
 570         max_ofs = EMPTY_SCAN_SIZE(c->sector_size);
 571         /* Scan only EMPTY_SCAN_SIZE of 0xFF before declaring it's empty */
 572         while(ofs < max_ofs && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
 573                 ofs += 4;
 574
 575         if (ofs == max_ofs) {
 576 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 577                 if (jffs2_cleanmarker_oob(c)) {
 578                         /* scan oob, take care of cleanmarker */
 579                         int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
 580                         jffs2_dbg(2, "jffs2_check_oob_empty returned %d\n",
 581                                   ret);
 582                         switch (ret) {
 583                         case 0:         return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
 584                         case 1:         return BLK_STATE_ALLDIRTY;
 585                         default:        return ret;
 586                         }
 587                 }
 588 #endif
 589                 jffs2_dbg(1, "Block at 0x%08x is empty (erased)\n",
 590                           jeb->offset);
 591                 if (c->cleanmarker_size == 0)
 592                         return BLK_STATE_CLEANMARKER;   /* don't bother with re-erase */
 593                 else
 594                         return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
 595         }
 596         if (ofs) {
 597                 jffs2_dbg(1, "Free space at %08x ends at %08x\n", jeb->offset,
 598                           jeb->offset + ofs);
 599                 if ((err = jffs2_prealloc_raw_node_refs(c, jeb, 1)))
 600                         return err;
 601                 if ((err = jffs2_scan_dirty_space(c, jeb, ofs)))
 602                         return err;
 603         }
 604
 605         /* Now ofs is a complete physical flash offset as it always was... */
 606         ofs += jeb->offset;
 607
 608         noise = 10;
 609
 610         dbg_summary("no summary found in jeb 0x%08x. Apply original scan.\n",jeb->offset);
 611
 612 scan_more:
 613         while(ofs < jeb->offset + c->sector_size) {
 614
 615                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 616
 617                 /* Make sure there are node refs available for use */
 618                 err = jffs2_prealloc_raw_node_refs(c, jeb, 2);
 619                 if (err)
 620                         return err;
 621
 622                 cond_resched();
 623
 624                 if (ofs & 3) {
 625                         pr_warn("Eep. ofs 0x%08x not word-aligned!\n", ofs);
 626                         ofs = PAD(ofs);
 627                         continue;
 628                 }
 629                 if (ofs == prevofs) {
 630                         pr_warn("ofs 0x%08x has already been seen. Skipping\n",
 631                                 ofs);
 632                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 633                                 return err;
 634                         ofs += 4;
 635                         continue;
 636                 }
 637                 prevofs = ofs;
 638
 639                 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
 640                         jffs2_dbg(1, "Fewer than %zd bytes left to end of block. (%x+%x<%x+%zx) Not reading\n",
 641                                   sizeof(struct jffs2_unknown_node),
 642                                   jeb->offset, c->sector_size, ofs,
 643                                   sizeof(*node));
 644                         if ((err = jffs2_scan_dirty_space(c, jeb, (jeb->offset + c->sector_size)-ofs)))
 645                                 return err;
 646                         break;
 647                 }
 648
 649                 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
 650                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 651                         jffs2_dbg(1, "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
 652                                   sizeof(struct jffs2_unknown_node),
 653                                   buf_len, ofs);
 654                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 655                         if (err)
 656                                 return err;
 657                         buf_ofs = ofs;
 658                 }
 659
 660                 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
 661
 662                 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
 663                         uint32_t inbuf_ofs;
 664                         uint32_t empty_start, scan_end;
 665
 666                         empty_start = ofs;
 667                         ofs += 4;
 668                         scan_end = min_t(uint32_t, EMPTY_SCAN_SIZE(c->sector_size)/8, buf_len);
 669
 670                         jffs2_dbg(1, "Found empty flash at 0x%08x\n", ofs);
 671                 more_empty:
 672                         inbuf_ofs = ofs - buf_ofs;
 673                         while (inbuf_ofs < scan_end) {
 674                                 if (unlikely(*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff)) {
 675                                         pr_warn("Empty flash at 0x%08x ends at 0x%08x\n",
 676                                                 empty_start, ofs);
 677                                         if ((err = jffs2_scan_dirty_space(c, jeb, ofs-empty_start)))
 678                                                 return err;
 679                                         goto scan_more;
 680                                 }
 681
 682                                 inbuf_ofs+=4;
 683                                 ofs += 4;
 684                         }
 685                         /* Ran off end. */
 686                         jffs2_dbg(1, "Empty flash to end of buffer at 0x%08x\n",
 687                                   ofs);
 688
 689                         /* If we're only checking the beginning of a block with a cleanmarker,
 690                            bail now */
 691                         if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&
 692                             c->cleanmarker_size && !jeb->dirty_size && !ref_next(jeb->first_node)) {
 693                                 jffs2_dbg(1, "%d bytes at start of block seems clean... assuming all clean\n",
 694                                           EMPTY_SCAN_SIZE(c->sector_size));
 695                                 return BLK_STATE_CLEANMARKER;
 696                         }
 697                         if (!buf_size && (scan_end != buf_len)) {/* XIP/point case */
 698                                 scan_end = buf_len;
 699                                 goto more_empty;
 700                         }
 701
 702                         /* See how much more there is to read in this eraseblock... */
 703                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 704                         if (!buf_len) {
 705                                 /* No more to read. Break out of main loop without marking
 706                                    this range of empty space as dirty (because it's not) */
 707                                 jffs2_dbg(1, "Empty flash at %08x runs to end of block. Treating as free_space\n",
 708                                           empty_start);
 709                                 break;
 710                         }
 711                         /* point never reaches here */
 712                         scan_end = buf_len;
 713                         jffs2_dbg(1, "Reading another 0x%x at 0x%08x\n",
 714                                   buf_len, ofs);
 715                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 716                         if (err)
 717                                 return err;
 718                         buf_ofs = ofs;
 719                         goto more_empty;
 720                 }
 721
 722                 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
 723                         pr_warn("Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n",
 724                                 ofs);
 725                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 726                                 return err;
 727                         ofs += 4;
 728                         continue;
 729                 }
 730                 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
 731                         jffs2_dbg(1, "Dirty bitmask at 0x%08x\n", ofs);
 732                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 733                                 return err;
 734                         ofs += 4;
 735                         continue;
 736                 }
 737                 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
 738                         pr_warn("Old JFFS2 bitmask found at 0x%08x\n", ofs);
 739                         pr_warn("You cannot use older JFFS2 filesystems with newer kernels\n");
 740                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 741                                 return err;
 742                         ofs += 4;
 743                         continue;
 744                 }
 745                 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
 746                         /* OK. We're out of possibilities. Whinge and move on */
 747                         noisy_printk(&noise, "%s(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n",
 748                                      __func__,
 749                                      JFFS2_MAGIC_BITMASK, ofs,
 750                                      je16_to_cpu(node->magic));
 751                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 752                                 return err;
 753                         ofs += 4;
 754                         continue;
 755                 }
 756                 /* We seem to have a node of sorts. Check the CRC */
 757                 crcnode.magic = node->magic;
 758                 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
 759                 crcnode.totlen = node->totlen;
 760                 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
 761
 762                 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
 763                         noisy_printk(&noise, "%s(): Node at 0x%08x {0x%04x, 0x%04x, 0x%08x) has invalid CRC 0x%08x (calculated 0x%08x)\n",
 764                                      __func__,
 765                                      ofs, je16_to_cpu(node->magic),
 766                                      je16_to_cpu(node->nodetype),
 767                                      je32_to_cpu(node->totlen),
 768                                      je32_to_cpu(node->hdr_crc),
 769                                      hdr_crc);
 770                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 771                                 return err;
 772                         ofs += 4;
 773                         continue;
 774                 }
 775
 776                 if (ofs + je32_to_cpu(node->totlen) > jeb->offset + c->sector_size) {
 777                         /* Eep. Node goes over the end of the erase block. */
 778                         pr_warn("Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
 779                                 ofs, je32_to_cpu(node->totlen));
 780                         pr_warn("Perhaps the file system was created with the wrong erase size?\n");
 781                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 782                                 return err;
 783                         ofs += 4;
 784                         continue;
 785                 }
 786
 787                 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
 788                         /* Wheee. This is an obsoleted node */
 789                         jffs2_dbg(2, "Node at 0x%08x is obsolete. Skipping\n",
 790                                   ofs);
 791                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 792                                 return err;
 793                         ofs += PAD(je32_to_cpu(node->totlen));
 794                         continue;
 795                 }
 796
 797                 switch(je16_to_cpu(node->nodetype)) {
 798                 case JFFS2_NODETYPE_INODE:
 799                         if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
 800                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 801                                 jffs2_dbg(1, "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
 802                                           sizeof(struct jffs2_raw_inode),
 803                                           buf_len, ofs);
 804                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 805                                 if (err)
 806                                         return err;
 807                                 buf_ofs = ofs;
 808                                 node = (void *)buf;
 809                         }
 810                         err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs, s);
 811                         if (err) return err;
 812                         ofs += PAD(je32_to_cpu(node->totlen));
 813                         break;
 814
 815                 case JFFS2_NODETYPE_DIRENT:
 816                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 817                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 818                                 jffs2_dbg(1, "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
 819                                           je32_to_cpu(node->totlen), buf_len,
 820                                           ofs);
 821                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 822                                 if (err)
 823                                         return err;
 824                                 buf_ofs = ofs;
 825                                 node = (void *)buf;
 826                         }
 827                         err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs, s);
 828                         if (err) return err;
 829                         ofs += PAD(je32_to_cpu(node->totlen));
 830                         break;
 831
 832 #ifdef CONFIG_JFFS2_FS_XATTR
 833                 case JFFS2_NODETYPE_XATTR:
 834                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 835                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 836                                 jffs2_dbg(1, "Fewer than %d bytes (xattr node) left to end of buf. Reading 0x%x at 0x%08x\n",
 837                                           je32_to_cpu(node->totlen), buf_len,
 838                                           ofs);
 839                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 840                                 if (err)
 841                                         return err;
 842                                 buf_ofs = ofs;
 843                                 node = (void *)buf;
 844                         }
 845                         err = jffs2_scan_xattr_node(c, jeb, (void *)node, ofs, s);
 846                         if (err)
 847                                 return err;
 848                         ofs += PAD(je32_to_cpu(node->totlen));
 849                         break;
 850                 case JFFS2_NODETYPE_XREF:
 851                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 852                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 853                                 jffs2_dbg(1, "Fewer than %d bytes (xref node) left to end of buf. Reading 0x%x at 0x%08x\n",
 854                                           je32_to_cpu(node->totlen), buf_len,
 855                                           ofs);
 856                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 857                                 if (err)
 858                                         return err;
 859                                 buf_ofs = ofs;
 860                                 node = (void *)buf;
 861                         }
 862                         err = jffs2_scan_xref_node(c, jeb, (void *)node, ofs, s);
 863                         if (err)
 864                                 return err;
 865                         ofs += PAD(je32_to_cpu(node->totlen));
 866                         break;
 867 #endif  /* CONFIG_JFFS2_FS_XATTR */
 868
 869                 case JFFS2_NODETYPE_CLEANMARKER:
 870                         jffs2_dbg(1, "CLEANMARKER node found at 0x%08x\n", ofs);
 871                         if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
 872                                 pr_notice("CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n",
 873                                           ofs, je32_to_cpu(node->totlen),
 874                                           c->cleanmarker_size);
 875                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
 876                                         return err;
 877                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 878                         } else if (jeb->first_node) {
 879                                 pr_notice("CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n",
 880                                           ofs, jeb->offset);
 881                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
 882                                         return err;
 883                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 884                         } else {
 885                                 jffs2_link_node_ref(c, jeb, ofs | REF_NORMAL, c->cleanmarker_size, NULL);
 886
 887                                 ofs += PAD(c->cleanmarker_size);
 888                         }
 889                         break;
 890
 891                 case JFFS2_NODETYPE_PADDING:
 892                         if (jffs2_sum_active())
 893                                 jffs2_sum_add_padding_mem(s, je32_to_cpu(node->totlen));
 894                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 895                                 return err;
 896                         ofs += PAD(je32_to_cpu(node->totlen));
 897                         break;
 898
 899                 default:
 900                         switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
 901                         case JFFS2_FEATURE_ROCOMPAT:
 902                                 pr_notice("Read-only compatible feature node (0x%04x) found at offset 0x%08x\n",
 903                                           je16_to_cpu(node->nodetype), ofs);
 904                                 c->flags |= JFFS2_SB_FLAG_RO;
 905                                 if (!(jffs2_is_readonly(c)))
 906                                         return -EROFS;
 907                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 908                                         return err;
 909                                 ofs += PAD(je32_to_cpu(node->totlen));
 910                                 break;
 911
 912                         case JFFS2_FEATURE_INCOMPAT:
 913                                 pr_notice("Incompatible feature node (0x%04x) found at offset 0x%08x\n",
 914                                           je16_to_cpu(node->nodetype), ofs);
 915                                 return -EINVAL;
 916
 917                         case JFFS2_FEATURE_RWCOMPAT_DELETE:
 918                                 jffs2_dbg(1, "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n",
 919                                           je16_to_cpu(node->nodetype), ofs);
 920                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 921                                         return err;
 922                                 ofs += PAD(je32_to_cpu(node->totlen));
 923                                 break;
 924
 925                         case JFFS2_FEATURE_RWCOMPAT_COPY: {
 926                                 jffs2_dbg(1, "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n",
 927                                           je16_to_cpu(node->nodetype), ofs);
 928
 929                                 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(node->totlen)), NULL);
 930
 931                                 /* We can't summarise nodes we don't grok */
 932                                 jffs2_sum_disable_collecting(s);
 933                                 ofs += PAD(je32_to_cpu(node->totlen));
 934                                 break;
 935                                 }
 936                         }
 937                 }
 938         }
 939
 940         if (jffs2_sum_active()) {
 941                 if (PAD(s->sum_size + JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size) {
 942                         dbg_summary("There is not enough space for "
 943                                 "summary information, disabling for this jeb!\n");
 944                         jffs2_sum_disable_collecting(s);
 945                 }
 946         }
 947
 948         jffs2_dbg(1, "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x, wasted 0x%08x\n",
 949                   jeb->offset, jeb->free_size, jeb->dirty_size,
 950                   jeb->unchecked_size, jeb->used_size, jeb->wasted_size);
 951
 952         /* mark_node_obsolete can add to wasted !! */
 953         if (jeb->wasted_size) {
 954                 jeb->dirty_size += jeb->wasted_size;
 955                 c->dirty_size += jeb->wasted_size;
 956                 c->wasted_size -= jeb->wasted_size;
 957                 jeb->wasted_size = 0;
 958         }
 959
 960         return jffs2_scan_classify_jeb(c, jeb);
 961 }
 962
 963 struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
 964 {
 965         struct jffs2_inode_cache *ic;
 966
 967         ic = jffs2_get_ino_cache(c, ino);
 968         if (ic)
 969                 return ic;
 970
 971         if (ino > c->highest_ino)
 972                 c->highest_ino = ino;
 973
 974         ic = jffs2_alloc_inode_cache();
 975         if (!ic) {
 976                 pr_notice("%s(): allocation of inode cache failed\n", __func__);
 977                 return NULL;
 978         }
 979         memset(ic, 0, sizeof(*ic));
 980
 981         ic->ino = ino;
 982         ic->nodes = (void *)ic;
 983         jffs2_add_ino_cache(c, ic);
 984         if (ino == 1)
 985                 ic->pino_nlink = 1;
 986         return ic;
 987 }
 988
 989 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 990                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s)
 991 {
 992         struct jffs2_inode_cache *ic;
 993         uint32_t crc, ino = je32_to_cpu(ri->ino);
 994
 995         jffs2_dbg(1, "%s(): Node at 0x%08x\n", __func__, ofs);
 996
 997         /* We do very little here now. Just check the ino# to which we should attribute
 998            this node; we can do all the CRC checking etc. later. There's a tradeoff here --
 999            we used to scan the flash once only, reading everything we want from it into
1000            memory, then building all our in-core data structures and freeing the extra
1001            information. Now we allow the first part of the mount to complete a lot quicker,
1002            but we have to go _back_ to the flash in order to finish the CRC checking, etc.
1003            Which means that the _full_ amount of time to get to proper write mode with GC
1004            operational may actually be _longer_ than before. Sucks to be me. */
1005
1006         /* Check the node CRC in any case. */
1007         crc = crc32(0, ri, sizeof(*ri)-8);
1008         if (crc != je32_to_cpu(ri->node_crc)) {
1009                 pr_notice("%s(): CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1010                           __func__, ofs, je32_to_cpu(ri->node_crc), crc);
1011                 /*
1012                  * We believe totlen because the CRC on the node
1013                  * _header_ was OK, just the node itself failed.
1014                  */
1015                 return jffs2_scan_dirty_space(c, jeb,
1016                                               PAD(je32_to_cpu(ri->totlen)));
1017         }
1018
1019         ic = jffs2_get_ino_cache(c, ino);
1020         if (!ic) {
1021                 ic = jffs2_scan_make_ino_cache(c, ino);
1022                 if (!ic)
1023                         return -ENOMEM;
1024         }
1025
1026         /* Wheee. It worked */
1027         jffs2_link_node_ref(c, jeb, ofs | REF_UNCHECKED, PAD(je32_to_cpu(ri->totlen)), ic);
1028
1029         jffs2_dbg(1, "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
1030                   je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
1031                   je32_to_cpu(ri->offset),
1032                   je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize));
1033
1034         pseudo_random += je32_to_cpu(ri->version);
1035
1036         if (jffs2_sum_active()) {
1037                 jffs2_sum_add_inode_mem(s, ri, ofs - jeb->offset);
1038         }
1039
1040         return 0;
1041 }
1042
1043 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
1044                                   struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s)
1045 {
1046         struct jffs2_full_dirent *fd;
1047         struct jffs2_inode_cache *ic;
1048         uint32_t checkedlen;
1049         uint32_t crc;
1050         int err;
1051
1052         jffs2_dbg(1, "%s(): Node at 0x%08x\n", __func__, ofs);
1053
1054         /* We don't get here unless the node is still valid, so we don't have to
1055            mask in the ACCURATE bit any more. */
1056         crc = crc32(0, rd, sizeof(*rd)-8);
1057
1058         if (crc != je32_to_cpu(rd->node_crc)) {
1059                 pr_notice("%s(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1060                           __func__, ofs, je32_to_cpu(rd->node_crc), crc);
1061                 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
1062                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1063                         return err;
1064                 return 0;
1065         }
1066
1067         pseudo_random += je32_to_cpu(rd->version);
1068
1069         /* Should never happen. Did. (OLPC trac #4184)*/
1070         checkedlen = strnlen(rd->name, rd->nsize);
1071         if (checkedlen < rd->nsize) {
1072                 pr_err("Dirent at %08x has zeroes in name. Truncating to %d chars\n",
1073                        ofs, checkedlen);
1074         }
1075         fd = jffs2_alloc_full_dirent(checkedlen+1);
1076         if (!fd) {
1077                 return -ENOMEM;
1078         }
1079         memcpy(&fd->name, rd->name, checkedlen);
1080         fd->name[checkedlen] = 0;
1081
1082         crc = crc32(0, fd->name, checkedlen);
1083         if (crc != je32_to_cpu(rd->name_crc)) {
1084                 pr_notice("%s(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1085                           __func__, ofs, je32_to_cpu(rd->name_crc), crc);
1086                 jffs2_dbg(1, "Name for which CRC failed is (now) '%s', ino #%d\n",
1087                           fd->name, je32_to_cpu(rd->ino));
1088                 jffs2_free_full_dirent(fd);
1089                 /* FIXME: Why do we believe totlen? */
1090                 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
1091                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1092                         return err;
1093                 return 0;
1094         }
1095         ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
1096         if (!ic) {
1097                 jffs2_free_full_dirent(fd);
1098                 return -ENOMEM;
1099         }
1100
1101         fd->raw = jffs2_link_node_ref(c, jeb, ofs | dirent_node_state(rd),
1102                                       PAD(je32_to_cpu(rd->totlen)), ic);
1103
1104         fd->next = NULL;
1105         fd->version = je32_to_cpu(rd->version);
1106         fd->ino = je32_to_cpu(rd->ino);
1107         fd->nhash = full_name_hash(NULL, fd->name, checkedlen);
1108         fd->type = rd->type;
1109         jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
1110
1111         if (jffs2_sum_active()) {
1112                 jffs2_sum_add_dirent_mem(s, rd, ofs - jeb->offset);
1113         }
1114
1115         return 0;
1116 }
1117
1118 static int count_list(struct list_head *l)
1119 {
1120         uint32_t count = 0;
1121         struct list_head *tmp;
1122
1123         list_for_each(tmp, l) {
1124                 count++;
1125         }
1126         return count;
1127 }
1128
1129 /* Note: This breaks if list_empty(head). I don't care. You
1130    might, if you copy this code and use it elsewhere :) */
1131 static void rotate_list(struct list_head *head, uint32_t count)
1132 {
1133         struct list_head *n = head->next;
1134
1135         list_del(head);
1136         while(count--) {
1137                 n = n->next;
1138         }
1139         list_add(head, n);
1140 }
1141
1142 void jffs2_rotate_lists(struct jffs2_sb_info *c)
1143 {
1144         uint32_t x;
1145         uint32_t rotateby;
1146
1147         x = count_list(&c->clean_list);
1148         if (x) {
1149                 rotateby = pseudo_random % x;
1150                 rotate_list((&c->clean_list), rotateby);
1151         }
1152
1153         x = count_list(&c->very_dirty_list);
1154         if (x) {
1155                 rotateby = pseudo_random % x;
1156                 rotate_list((&c->very_dirty_list), rotateby);
1157         }
1158
1159         x = count_list(&c->dirty_list);
1160         if (x) {
1161                 rotateby = pseudo_random % x;
1162                 rotate_list((&c->dirty_list), rotateby);
1163         }
1164
1165         x = count_list(&c->erasable_list);
1166         if (x) {
1167                 rotateby = pseudo_random % x;
1168                 rotate_list((&c->erasable_list), rotateby);
1169         }
1170
1171         if (c->nr_erasing_blocks) {
1172                 rotateby = pseudo_random % c->nr_erasing_blocks;
1173                 rotate_list((&c->erase_pending_list), rotateby);
1174         }
1175
1176         if (c->nr_free_blocks) {
1177                 rotateby = pseudo_random % c->nr_free_blocks;
1178                 rotate_list((&c->free_list), rotateby);
1179         }
1180 }