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                                 /* Now, make sure the summary itself is available */
 514                                 if (sumlen > buf_size) {
 515                                         /* Need to kmalloc for this. */
 516                                         sumptr = kmalloc(sumlen, GFP_KERNEL);
 517                                         if (!sumptr)
 518                                                 return -ENOMEM;
 519                                         memcpy(sumptr + sumlen - buf_len, buf + buf_size - buf_len, buf_len);
 520                                 }
 521                                 if (buf_len < sumlen) {
 522                                         /* Need to read more so that the entire summary node is present */
 523                                         err = jffs2_fill_scan_buf(c, sumptr,
 524                                                                   jeb->offset + c->sector_size - sumlen,
 525                                                                   sumlen - buf_len);
 526                                         if (err)
 527                                                 return err;
 528                                 }
 529                         }
 530
 531                 }
 532
 533                 if (sumptr) {
 534                         err = jffs2_sum_scan_sumnode(c, jeb, sumptr, sumlen, &pseudo_random);
 535
 536                         if (buf_size && sumlen > buf_size)
 537                                 kfree(sumptr);
 538                         /* If it returns with a real error, bail.
 539                            If it returns positive, that's a block classification
 540                            (i.e. BLK_STATE_xxx) so return that too.
 541                            If it returns zero, fall through to full scan. */
 542                         if (err)
 543                                 return err;
 544                 }
 545         }
 546
 547         buf_ofs = jeb->offset;
 548
 549         if (!buf_size) {
 550                 /* This is the XIP case -- we're reading _directly_ from the flash chip */
 551                 buf_len = c->sector_size;
 552         } else {
 553                 buf_len = EMPTY_SCAN_SIZE(c->sector_size);
 554                 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
 555                 if (err)
 556                         return err;
 557         }
 558
 559         /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
 560         ofs = 0;
 561         max_ofs = EMPTY_SCAN_SIZE(c->sector_size);
 562         /* Scan only EMPTY_SCAN_SIZE of 0xFF before declaring it's empty */
 563         while(ofs < max_ofs && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
 564                 ofs += 4;
 565
 566         if (ofs == max_ofs) {
 567 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 568                 if (jffs2_cleanmarker_oob(c)) {
 569                         /* scan oob, take care of cleanmarker */
 570                         int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
 571                         jffs2_dbg(2, "jffs2_check_oob_empty returned %d\n",
 572                                   ret);
 573                         switch (ret) {
 574                         case 0:         return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
 575                         case 1:         return BLK_STATE_ALLDIRTY;
 576                         default:        return ret;
 577                         }
 578                 }
 579 #endif
 580                 jffs2_dbg(1, "Block at 0x%08x is empty (erased)\n",
 581                           jeb->offset);
 582                 if (c->cleanmarker_size == 0)
 583                         return BLK_STATE_CLEANMARKER;   /* don't bother with re-erase */
 584                 else
 585                         return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
 586         }
 587         if (ofs) {
 588                 jffs2_dbg(1, "Free space at %08x ends at %08x\n", jeb->offset,
 589                           jeb->offset + ofs);
 590                 if ((err = jffs2_prealloc_raw_node_refs(c, jeb, 1)))
 591                         return err;
 592                 if ((err = jffs2_scan_dirty_space(c, jeb, ofs)))
 593                         return err;
 594         }
 595
 596         /* Now ofs is a complete physical flash offset as it always was... */
 597         ofs += jeb->offset;
 598
 599         noise = 10;
 600
 601         dbg_summary("no summary found in jeb 0x%08x. Apply original scan.\n",jeb->offset);
 602
 603 scan_more:
 604         while(ofs < jeb->offset + c->sector_size) {
 605
 606                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 607
 608                 /* Make sure there are node refs available for use */
 609                 err = jffs2_prealloc_raw_node_refs(c, jeb, 2);
 610                 if (err)
 611                         return err;
 612
 613                 cond_resched();
 614
 615                 if (ofs & 3) {
 616                         pr_warn("Eep. ofs 0x%08x not word-aligned!\n", ofs);
 617                         ofs = PAD(ofs);
 618                         continue;
 619                 }
 620                 if (ofs == prevofs) {
 621                         pr_warn("ofs 0x%08x has already been seen. Skipping\n",
 622                                 ofs);
 623                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 624                                 return err;
 625                         ofs += 4;
 626                         continue;
 627                 }
 628                 prevofs = ofs;
 629
 630                 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
 631                         jffs2_dbg(1, "Fewer than %zd bytes left to end of block. (%x+%x<%x+%zx) Not reading\n",
 632                                   sizeof(struct jffs2_unknown_node),
 633                                   jeb->offset, c->sector_size, ofs,
 634                                   sizeof(*node));
 635                         if ((err = jffs2_scan_dirty_space(c, jeb, (jeb->offset + c->sector_size)-ofs)))
 636                                 return err;
 637                         break;
 638                 }
 639
 640                 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
 641                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 642                         jffs2_dbg(1, "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
 643                                   sizeof(struct jffs2_unknown_node),
 644                                   buf_len, ofs);
 645                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 646                         if (err)
 647                                 return err;
 648                         buf_ofs = ofs;
 649                 }
 650
 651                 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
 652
 653                 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
 654                         uint32_t inbuf_ofs;
 655                         uint32_t empty_start, scan_end;
 656
 657                         empty_start = ofs;
 658                         ofs += 4;
 659                         scan_end = min_t(uint32_t, EMPTY_SCAN_SIZE(c->sector_size)/8, buf_len);
 660
 661                         jffs2_dbg(1, "Found empty flash at 0x%08x\n", ofs);
 662                 more_empty:
 663                         inbuf_ofs = ofs - buf_ofs;
 664                         while (inbuf_ofs < scan_end) {
 665                                 if (unlikely(*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff)) {
 666                                         pr_warn("Empty flash at 0x%08x ends at 0x%08x\n",
 667                                                 empty_start, ofs);
 668                                         if ((err = jffs2_scan_dirty_space(c, jeb, ofs-empty_start)))
 669                                                 return err;
 670                                         goto scan_more;
 671                                 }
 672
 673                                 inbuf_ofs+=4;
 674                                 ofs += 4;
 675                         }
 676                         /* Ran off end. */
 677                         jffs2_dbg(1, "Empty flash to end of buffer at 0x%08x\n",
 678                                   ofs);
 679
 680                         /* If we're only checking the beginning of a block with a cleanmarker,
 681                            bail now */
 682                         if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&
 683                             c->cleanmarker_size && !jeb->dirty_size && !ref_next(jeb->first_node)) {
 684                                 jffs2_dbg(1, "%d bytes at start of block seems clean... assuming all clean\n",
 685                                           EMPTY_SCAN_SIZE(c->sector_size));
 686                                 return BLK_STATE_CLEANMARKER;
 687                         }
 688                         if (!buf_size && (scan_end != buf_len)) {/* XIP/point case */
 689                                 scan_end = buf_len;
 690                                 goto more_empty;
 691                         }
 692
 693                         /* See how much more there is to read in this eraseblock... */
 694                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 695                         if (!buf_len) {
 696                                 /* No more to read. Break out of main loop without marking
 697                                    this range of empty space as dirty (because it's not) */
 698                                 jffs2_dbg(1, "Empty flash at %08x runs to end of block. Treating as free_space\n",
 699                                           empty_start);
 700                                 break;
 701                         }
 702                         /* point never reaches here */
 703                         scan_end = buf_len;
 704                         jffs2_dbg(1, "Reading another 0x%x at 0x%08x\n",
 705                                   buf_len, ofs);
 706                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 707                         if (err)
 708                                 return err;
 709                         buf_ofs = ofs;
 710                         goto more_empty;
 711                 }
 712
 713                 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
 714                         pr_warn("Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n",
 715                                 ofs);
 716                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 717                                 return err;
 718                         ofs += 4;
 719                         continue;
 720                 }
 721                 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
 722                         jffs2_dbg(1, "Dirty bitmask at 0x%08x\n", ofs);
 723                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 724                                 return err;
 725                         ofs += 4;
 726                         continue;
 727                 }
 728                 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
 729                         pr_warn("Old JFFS2 bitmask found at 0x%08x\n", ofs);
 730                         pr_warn("You cannot use older JFFS2 filesystems with newer kernels\n");
 731                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 732                                 return err;
 733                         ofs += 4;
 734                         continue;
 735                 }
 736                 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
 737                         /* OK. We're out of possibilities. Whinge and move on */
 738                         noisy_printk(&noise, "%s(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n",
 739                                      __func__,
 740                                      JFFS2_MAGIC_BITMASK, ofs,
 741                                      je16_to_cpu(node->magic));
 742                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 743                                 return err;
 744                         ofs += 4;
 745                         continue;
 746                 }
 747                 /* We seem to have a node of sorts. Check the CRC */
 748                 crcnode.magic = node->magic;
 749                 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
 750                 crcnode.totlen = node->totlen;
 751                 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
 752
 753                 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
 754                         noisy_printk(&noise, "%s(): Node at 0x%08x {0x%04x, 0x%04x, 0x%08x) has invalid CRC 0x%08x (calculated 0x%08x)\n",
 755                                      __func__,
 756                                      ofs, je16_to_cpu(node->magic),
 757                                      je16_to_cpu(node->nodetype),
 758                                      je32_to_cpu(node->totlen),
 759                                      je32_to_cpu(node->hdr_crc),
 760                                      hdr_crc);
 761                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 762                                 return err;
 763                         ofs += 4;
 764                         continue;
 765                 }
 766
 767                 if (ofs + je32_to_cpu(node->totlen) > jeb->offset + c->sector_size) {
 768                         /* Eep. Node goes over the end of the erase block. */
 769                         pr_warn("Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
 770                                 ofs, je32_to_cpu(node->totlen));
 771                         pr_warn("Perhaps the file system was created with the wrong erase size?\n");
 772                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 773                                 return err;
 774                         ofs += 4;
 775                         continue;
 776                 }
 777
 778                 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
 779                         /* Wheee. This is an obsoleted node */
 780                         jffs2_dbg(2, "Node at 0x%08x is obsolete. Skipping\n",
 781                                   ofs);
 782                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 783                                 return err;
 784                         ofs += PAD(je32_to_cpu(node->totlen));
 785                         continue;
 786                 }
 787
 788                 switch(je16_to_cpu(node->nodetype)) {
 789                 case JFFS2_NODETYPE_INODE:
 790                         if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
 791                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 792                                 jffs2_dbg(1, "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
 793                                           sizeof(struct jffs2_raw_inode),
 794                                           buf_len, ofs);
 795                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 796                                 if (err)
 797                                         return err;
 798                                 buf_ofs = ofs;
 799                                 node = (void *)buf;
 800                         }
 801                         err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs, s);
 802                         if (err) return err;
 803                         ofs += PAD(je32_to_cpu(node->totlen));
 804                         break;
 805
 806                 case JFFS2_NODETYPE_DIRENT:
 807                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 808                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 809                                 jffs2_dbg(1, "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
 810                                           je32_to_cpu(node->totlen), buf_len,
 811                                           ofs);
 812                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 813                                 if (err)
 814                                         return err;
 815                                 buf_ofs = ofs;
 816                                 node = (void *)buf;
 817                         }
 818                         err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs, s);
 819                         if (err) return err;
 820                         ofs += PAD(je32_to_cpu(node->totlen));
 821                         break;
 822
 823 #ifdef CONFIG_JFFS2_FS_XATTR
 824                 case JFFS2_NODETYPE_XATTR:
 825                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 826                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 827                                 jffs2_dbg(1, "Fewer than %d bytes (xattr node) left to end of buf. Reading 0x%x at 0x%08x\n",
 828                                           je32_to_cpu(node->totlen), buf_len,
 829                                           ofs);
 830                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 831                                 if (err)
 832                                         return err;
 833                                 buf_ofs = ofs;
 834                                 node = (void *)buf;
 835                         }
 836                         err = jffs2_scan_xattr_node(c, jeb, (void *)node, ofs, s);
 837                         if (err)
 838                                 return err;
 839                         ofs += PAD(je32_to_cpu(node->totlen));
 840                         break;
 841                 case JFFS2_NODETYPE_XREF:
 842                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 843                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 844                                 jffs2_dbg(1, "Fewer than %d bytes (xref node) left to end of buf. Reading 0x%x at 0x%08x\n",
 845                                           je32_to_cpu(node->totlen), buf_len,
 846                                           ofs);
 847                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 848                                 if (err)
 849                                         return err;
 850                                 buf_ofs = ofs;
 851                                 node = (void *)buf;
 852                         }
 853                         err = jffs2_scan_xref_node(c, jeb, (void *)node, ofs, s);
 854                         if (err)
 855                                 return err;
 856                         ofs += PAD(je32_to_cpu(node->totlen));
 857                         break;
 858 #endif  /* CONFIG_JFFS2_FS_XATTR */
 859
 860                 case JFFS2_NODETYPE_CLEANMARKER:
 861                         jffs2_dbg(1, "CLEANMARKER node found at 0x%08x\n", ofs);
 862                         if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
 863                                 pr_notice("CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n",
 864                                           ofs, je32_to_cpu(node->totlen),
 865                                           c->cleanmarker_size);
 866                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
 867                                         return err;
 868                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 869                         } else if (jeb->first_node) {
 870                                 pr_notice("CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n",
 871                                           ofs, jeb->offset);
 872                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
 873                                         return err;
 874                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 875                         } else {
 876                                 jffs2_link_node_ref(c, jeb, ofs | REF_NORMAL, c->cleanmarker_size, NULL);
 877
 878                                 ofs += PAD(c->cleanmarker_size);
 879                         }
 880                         break;
 881
 882                 case JFFS2_NODETYPE_PADDING:
 883                         if (jffs2_sum_active())
 884                                 jffs2_sum_add_padding_mem(s, je32_to_cpu(node->totlen));
 885                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 886                                 return err;
 887                         ofs += PAD(je32_to_cpu(node->totlen));
 888                         break;
 889
 890                 default:
 891                         switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
 892                         case JFFS2_FEATURE_ROCOMPAT:
 893                                 pr_notice("Read-only compatible feature node (0x%04x) found at offset 0x%08x\n",
 894                                           je16_to_cpu(node->nodetype), ofs);
 895                                 c->flags |= JFFS2_SB_FLAG_RO;
 896                                 if (!(jffs2_is_readonly(c)))
 897                                         return -EROFS;
 898                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 899                                         return err;
 900                                 ofs += PAD(je32_to_cpu(node->totlen));
 901                                 break;
 902
 903                         case JFFS2_FEATURE_INCOMPAT:
 904                                 pr_notice("Incompatible feature node (0x%04x) found at offset 0x%08x\n",
 905                                           je16_to_cpu(node->nodetype), ofs);
 906                                 return -EINVAL;
 907
 908                         case JFFS2_FEATURE_RWCOMPAT_DELETE:
 909                                 jffs2_dbg(1, "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n",
 910                                           je16_to_cpu(node->nodetype), ofs);
 911                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 912                                         return err;
 913                                 ofs += PAD(je32_to_cpu(node->totlen));
 914                                 break;
 915
 916                         case JFFS2_FEATURE_RWCOMPAT_COPY: {
 917                                 jffs2_dbg(1, "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n",
 918                                           je16_to_cpu(node->nodetype), ofs);
 919
 920                                 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(node->totlen)), NULL);
 921
 922                                 /* We can't summarise nodes we don't grok */
 923                                 jffs2_sum_disable_collecting(s);
 924                                 ofs += PAD(je32_to_cpu(node->totlen));
 925                                 break;
 926                                 }
 927                         }
 928                 }
 929         }
 930
 931         if (jffs2_sum_active()) {
 932                 if (PAD(s->sum_size + JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size) {
 933                         dbg_summary("There is not enough space for "
 934                                 "summary information, disabling for this jeb!\n");
 935                         jffs2_sum_disable_collecting(s);
 936                 }
 937         }
 938
 939         jffs2_dbg(1, "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x, wasted 0x%08x\n",
 940                   jeb->offset, jeb->free_size, jeb->dirty_size,
 941                   jeb->unchecked_size, jeb->used_size, jeb->wasted_size);
 942
 943         /* mark_node_obsolete can add to wasted !! */
 944         if (jeb->wasted_size) {
 945                 jeb->dirty_size += jeb->wasted_size;
 946                 c->dirty_size += jeb->wasted_size;
 947                 c->wasted_size -= jeb->wasted_size;
 948                 jeb->wasted_size = 0;
 949         }
 950
 951         return jffs2_scan_classify_jeb(c, jeb);
 952 }
 953
 954 struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
 955 {
 956         struct jffs2_inode_cache *ic;
 957
 958         ic = jffs2_get_ino_cache(c, ino);
 959         if (ic)
 960                 return ic;
 961
 962         if (ino > c->highest_ino)
 963                 c->highest_ino = ino;
 964
 965         ic = jffs2_alloc_inode_cache();
 966         if (!ic) {
 967                 pr_notice("%s(): allocation of inode cache failed\n", __func__);
 968                 return NULL;
 969         }
 970         memset(ic, 0, sizeof(*ic));
 971
 972         ic->ino = ino;
 973         ic->nodes = (void *)ic;
 974         jffs2_add_ino_cache(c, ic);
 975         if (ino == 1)
 976                 ic->pino_nlink = 1;
 977         return ic;
 978 }
 979
 980 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 981                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s)
 982 {
 983         struct jffs2_inode_cache *ic;
 984         uint32_t crc, ino = je32_to_cpu(ri->ino);
 985
 986         jffs2_dbg(1, "%s(): Node at 0x%08x\n", __func__, ofs);
 987
 988         /* We do very little here now. Just check the ino# to which we should attribute
 989            this node; we can do all the CRC checking etc. later. There's a tradeoff here --
 990            we used to scan the flash once only, reading everything we want from it into
 991            memory, then building all our in-core data structures and freeing the extra
 992            information. Now we allow the first part of the mount to complete a lot quicker,
 993            but we have to go _back_ to the flash in order to finish the CRC checking, etc.
 994            Which means that the _full_ amount of time to get to proper write mode with GC
 995            operational may actually be _longer_ than before. Sucks to be me. */
 996
 997         /* Check the node CRC in any case. */
 998         crc = crc32(0, ri, sizeof(*ri)-8);
 999         if (crc != je32_to_cpu(ri->node_crc)) {
1000                 pr_notice("%s(): CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1001                           __func__, ofs, je32_to_cpu(ri->node_crc), crc);
1002                 /*
1003                  * We believe totlen because the CRC on the node
1004                  * _header_ was OK, just the node itself failed.
1005                  */
1006                 return jffs2_scan_dirty_space(c, jeb,
1007                                               PAD(je32_to_cpu(ri->totlen)));
1008         }
1009
1010         ic = jffs2_get_ino_cache(c, ino);
1011         if (!ic) {
1012                 ic = jffs2_scan_make_ino_cache(c, ino);
1013                 if (!ic)
1014                         return -ENOMEM;
1015         }
1016
1017         /* Wheee. It worked */
1018         jffs2_link_node_ref(c, jeb, ofs | REF_UNCHECKED, PAD(je32_to_cpu(ri->totlen)), ic);
1019
1020         jffs2_dbg(1, "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
1021                   je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
1022                   je32_to_cpu(ri->offset),
1023                   je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize));
1024
1025         pseudo_random += je32_to_cpu(ri->version);
1026
1027         if (jffs2_sum_active()) {
1028                 jffs2_sum_add_inode_mem(s, ri, ofs - jeb->offset);
1029         }
1030
1031         return 0;
1032 }
1033
1034 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
1035                                   struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s)
1036 {
1037         struct jffs2_full_dirent *fd;
1038         struct jffs2_inode_cache *ic;
1039         uint32_t checkedlen;
1040         uint32_t crc;
1041         int err;
1042
1043         jffs2_dbg(1, "%s(): Node at 0x%08x\n", __func__, ofs);
1044
1045         /* We don't get here unless the node is still valid, so we don't have to
1046            mask in the ACCURATE bit any more. */
1047         crc = crc32(0, rd, sizeof(*rd)-8);
1048
1049         if (crc != je32_to_cpu(rd->node_crc)) {
1050                 pr_notice("%s(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1051                           __func__, ofs, je32_to_cpu(rd->node_crc), crc);
1052                 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
1053                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1054                         return err;
1055                 return 0;
1056         }
1057
1058         pseudo_random += je32_to_cpu(rd->version);
1059
1060         /* Should never happen. Did. (OLPC trac #4184)*/
1061         checkedlen = strnlen(rd->name, rd->nsize);
1062         if (checkedlen < rd->nsize) {
1063                 pr_err("Dirent at %08x has zeroes in name. Truncating to %d chars\n",
1064                        ofs, checkedlen);
1065         }
1066         fd = jffs2_alloc_full_dirent(checkedlen+1);
1067         if (!fd) {
1068                 return -ENOMEM;
1069         }
1070         memcpy(&fd->name, rd->name, checkedlen);
1071         fd->name[checkedlen] = 0;
1072
1073         crc = crc32(0, fd->name, rd->nsize);
1074         if (crc != je32_to_cpu(rd->name_crc)) {
1075                 pr_notice("%s(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1076                           __func__, ofs, je32_to_cpu(rd->name_crc), crc);
1077                 jffs2_dbg(1, "Name for which CRC failed is (now) '%s', ino #%d\n",
1078                           fd->name, je32_to_cpu(rd->ino));
1079                 jffs2_free_full_dirent(fd);
1080                 /* FIXME: Why do we believe totlen? */
1081                 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
1082                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1083                         return err;
1084                 return 0;
1085         }
1086         ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
1087         if (!ic) {
1088                 jffs2_free_full_dirent(fd);
1089                 return -ENOMEM;
1090         }
1091
1092         fd->raw = jffs2_link_node_ref(c, jeb, ofs | dirent_node_state(rd),
1093                                       PAD(je32_to_cpu(rd->totlen)), ic);
1094
1095         fd->next = NULL;
1096         fd->version = je32_to_cpu(rd->version);
1097         fd->ino = je32_to_cpu(rd->ino);
1098         fd->nhash = full_name_hash(fd->name, checkedlen);
1099         fd->type = rd->type;
1100         jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
1101
1102         if (jffs2_sum_active()) {
1103                 jffs2_sum_add_dirent_mem(s, rd, ofs - jeb->offset);
1104         }
1105
1106         return 0;
1107 }
1108
1109 static int count_list(struct list_head *l)
1110 {
1111         uint32_t count = 0;
1112         struct list_head *tmp;
1113
1114         list_for_each(tmp, l) {
1115                 count++;
1116         }
1117         return count;
1118 }
1119
1120 /* Note: This breaks if list_empty(head). I don't care. You
1121    might, if you copy this code and use it elsewhere :) */
1122 static void rotate_list(struct list_head *head, uint32_t count)
1123 {
1124         struct list_head *n = head->next;
1125
1126         list_del(head);
1127         while(count--) {
1128                 n = n->next;
1129         }
1130         list_add(head, n);
1131 }
1132
1133 void jffs2_rotate_lists(struct jffs2_sb_info *c)
1134 {
1135         uint32_t x;
1136         uint32_t rotateby;
1137
1138         x = count_list(&c->clean_list);
1139         if (x) {
1140                 rotateby = pseudo_random % x;
1141                 rotate_list((&c->clean_list), rotateby);
1142         }
1143
1144         x = count_list(&c->very_dirty_list);
1145         if (x) {
1146                 rotateby = pseudo_random % x;
1147                 rotate_list((&c->very_dirty_list), rotateby);
1148         }
1149
1150         x = count_list(&c->dirty_list);
1151         if (x) {
1152                 rotateby = pseudo_random % x;
1153                 rotate_list((&c->dirty_list), rotateby);
1154         }
1155
1156         x = count_list(&c->erasable_list);
1157         if (x) {
1158                 rotateby = pseudo_random % x;
1159                 rotate_list((&c->erasable_list), rotateby);
1160         }
1161
1162         if (c->nr_erasing_blocks) {
1163                 rotateby = pseudo_random % c->nr_erasing_blocks;
1164                 rotate_list((&c->erase_pending_list), rotateby);
1165         }
1166
1167         if (c->nr_free_blocks) {
1168                 rotateby = pseudo_random % c->nr_free_blocks;
1169                 rotate_list((&c->free_list), rotateby);
1170         }
1171 }