linux/fs/jffs2/scan.c
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   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, ...)                                   \
  28do {                                                                    \
  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
  37static uint32_t pseudo_random;
  38
  39static 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 */
  46static 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);
  48static 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
  51static 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
  62static 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
  69static 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
  91int 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
 288static 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
 308int 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
 328static 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
 384static 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 */
 443static 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
 555full_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
 612scan_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
 963struct 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
 989static 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
1043static 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
1118static 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 :) */
1131static 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
1142void 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}
1181