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