git.oblomov.eu Git - linux-2.6/blob - fs/jffs2/scan.c

   1 /*
   2  * JFFS2 -- Journalling Flash File System, Version 2.
   3  *
   4  * Copyright © 2001-2007 Red Hat, Inc.
   5  *
   6  * Created by David Woodhouse <dwmw2@infradead.org>
   7  *
   8  * For licensing information, see the file 'LICENCE' in this directory.
   9  *
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/sched.h>
  14 #include <linux/slab.h>
  15 #include <linux/mtd/mtd.h>
  16 #include <linux/pagemap.h>
  17 #include <linux/crc32.h>
  18 #include <linux/compiler.h>
  19 #include "nodelist.h"
  20 #include "summary.h"
  21 #include "debug.h"
  22
  23 #define DEFAULT_EMPTY_SCAN_SIZE 1024
  24
  25 #define noisy_printk(noise, args...) do { \
  26         if (*(noise)) { \
  27                 printk(KERN_NOTICE args); \
  28                  (*(noise))--; \
  29                  if (!(*(noise))) { \
  30                          printk(KERN_NOTICE "Further such events for this erase block will not be printed\n"); \
  31                  } \
  32         } \
  33 } while(0)
  34
  35 static uint32_t pseudo_random;
  36
  37 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  38                                   unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s);
  39
  40 /* These helper functions _must_ increase ofs and also do the dirty/used space accounting.
  41  * Returning an error will abort the mount - bad checksums etc. should just mark the space
  42  * as dirty.
  43  */
  44 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  45                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s);
  46 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  47                                  struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s);
  48
  49 static inline int min_free(struct jffs2_sb_info *c)
  50 {
  51         uint32_t min = 2 * sizeof(struct jffs2_raw_inode);
  52 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
  53         if (!jffs2_can_mark_obsolete(c) && min < c->wbuf_pagesize)
  54                 return c->wbuf_pagesize;
  55 #endif
  56         return min;
  57
  58 }
  59
  60 static inline uint32_t EMPTY_SCAN_SIZE(uint32_t sector_size) {
  61         if (sector_size < DEFAULT_EMPTY_SCAN_SIZE)
  62                 return sector_size;
  63         else
  64                 return DEFAULT_EMPTY_SCAN_SIZE;
  65 }
  66
  67 static int file_dirty(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
  68 {
  69         int ret;
  70
  71         if ((ret = jffs2_prealloc_raw_node_refs(c, jeb, 1)))
  72                 return ret;
  73         if ((ret = jffs2_scan_dirty_space(c, jeb, jeb->free_size)))
  74                 return ret;
  75         /* Turned wasted size into dirty, since we apparently
  76            think it's recoverable now. */
  77         jeb->dirty_size += jeb->wasted_size;
  78         c->dirty_size += jeb->wasted_size;
  79         c->wasted_size -= jeb->wasted_size;
  80         jeb->wasted_size = 0;
  81         if (VERYDIRTY(c, jeb->dirty_size)) {
  82                 list_add(&jeb->list, &c->very_dirty_list);
  83         } else {
  84                 list_add(&jeb->list, &c->dirty_list);
  85         }
  86         return 0;
  87 }
  88
  89 int jffs2_scan_medium(struct jffs2_sb_info *c)
  90 {
  91         int i, ret;
  92         uint32_t empty_blocks = 0, bad_blocks = 0;
  93         unsigned char *flashbuf = NULL;
  94         uint32_t buf_size = 0;
  95         struct jffs2_summary *s = NULL; /* summary info collected by the scan process */
  96 #ifndef __ECOS
  97         size_t pointlen;
  98
  99         if (c->mtd->point) {
 100                 ret = c->mtd->point(c->mtd, 0, c->mtd->size, &pointlen,
 101                                     (void **)&flashbuf, NULL);
 102                 if (!ret && pointlen < c->mtd->size) {
 103                         /* Don't muck about if it won't let us point to the whole flash */
 104                         D1(printk(KERN_DEBUG "MTD point returned len too short: 0x%zx\n", pointlen));
 105                         c->mtd->unpoint(c->mtd, 0, pointlen);
 106                         flashbuf = NULL;
 107                 }
 108                 if (ret)
 109                         D1(printk(KERN_DEBUG "MTD point failed %d\n", ret));
 110         }
 111 #endif
 112         if (!flashbuf) {
 113                 /* For NAND it's quicker to read a whole eraseblock at a time,
 114                    apparently */
 115                 if (jffs2_cleanmarker_oob(c))
 116                         buf_size = c->sector_size;
 117                 else
 118                         buf_size = PAGE_SIZE;
 119
 120                 /* Respect kmalloc limitations */
 121                 if (buf_size > 128*1024)
 122                         buf_size = 128*1024;
 123
 124                 D1(printk(KERN_DEBUG "Allocating readbuf of %d bytes\n", buf_size));
 125                 flashbuf = kmalloc(buf_size, GFP_KERNEL);
 126                 if (!flashbuf)
 127                         return -ENOMEM;
 128         }
 129
 130         if (jffs2_sum_active()) {
 131                 s = kzalloc(sizeof(struct jffs2_summary), GFP_KERNEL);
 132                 if (!s) {
 133                         kfree(flashbuf);
 134                         JFFS2_WARNING("Can't allocate memory for summary\n");
 135                         return -ENOMEM;
 136                 }
 137         }
 138
 139         for (i=0; i<c->nr_blocks; i++) {
 140                 struct jffs2_eraseblock *jeb = &c->blocks[i];
 141
 142                 cond_resched();
 143
 144                 /* reset summary info for next eraseblock scan */
 145                 jffs2_sum_reset_collected(s);
 146
 147                 ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset),
 148                                                 buf_size, s);
 149
 150                 if (ret < 0)
 151                         goto out;
 152
 153                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 154
 155                 /* Now decide which list to put it on */
 156                 switch(ret) {
 157                 case BLK_STATE_ALLFF:
 158                         /*
 159                          * Empty block.   Since we can't be sure it
 160                          * was entirely erased, we just queue it for erase
 161                          * again.  It will be marked as such when the erase
 162                          * is complete.  Meanwhile we still count it as empty
 163                          * for later checks.
 164                          */
 165                         empty_blocks++;
 166                         list_add(&jeb->list, &c->erase_pending_list);
 167                         c->nr_erasing_blocks++;
 168                         break;
 169
 170                 case BLK_STATE_CLEANMARKER:
 171                         /* Only a CLEANMARKER node is valid */
 172                         if (!jeb->dirty_size) {
 173                                 /* It's actually free */
 174                                 list_add(&jeb->list, &c->free_list);
 175                                 c->nr_free_blocks++;
 176                         } else {
 177                                 /* Dirt */
 178                                 D1(printk(KERN_DEBUG "Adding all-dirty block at 0x%08x to erase_pending_list\n", jeb->offset));
 179                                 list_add(&jeb->list, &c->erase_pending_list);
 180                                 c->nr_erasing_blocks++;
 181                         }
 182                         break;
 183
 184                 case BLK_STATE_CLEAN:
 185                         /* Full (or almost full) of clean data. Clean list */
 186                         list_add(&jeb->list, &c->clean_list);
 187                         break;
 188
 189                 case BLK_STATE_PARTDIRTY:
 190                         /* Some data, but not full. Dirty list. */
 191                         /* We want to remember the block with most free space
 192                         and stick it in the 'nextblock' position to start writing to it. */
 193                         if (jeb->free_size > min_free(c) &&
 194                                         (!c->nextblock || c->nextblock->free_size < jeb->free_size)) {
 195                                 /* Better candidate for the next writes to go to */
 196                                 if (c->nextblock) {
 197                                         ret = file_dirty(c, c->nextblock);
 198                                         if (ret)
 199                                                 return ret;
 200                                         /* deleting summary information of the old nextblock */
 201                                         jffs2_sum_reset_collected(c->summary);
 202                                 }
 203                                 /* update collected summary information for the current nextblock */
 204                                 jffs2_sum_move_collected(c, s);
 205                                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): new nextblock = 0x%08x\n", jeb->offset));
 206                                 c->nextblock = jeb;
 207                         } else {
 208                                 ret = file_dirty(c, jeb);
 209                                 if (ret)
 210                                         return ret;
 211                         }
 212                         break;
 213
 214                 case BLK_STATE_ALLDIRTY:
 215                         /* Nothing valid - not even a clean marker. Needs erasing. */
 216                         /* For now we just put it on the erasing list. We'll start the erases later */
 217                         D1(printk(KERN_NOTICE "JFFS2: Erase block at 0x%08x is not formatted. It will be erased\n", jeb->offset));
 218                         list_add(&jeb->list, &c->erase_pending_list);
 219                         c->nr_erasing_blocks++;
 220                         break;
 221
 222                 case BLK_STATE_BADBLOCK:
 223                         D1(printk(KERN_NOTICE "JFFS2: Block at 0x%08x is bad\n", jeb->offset));
 224                         list_add(&jeb->list, &c->bad_list);
 225                         c->bad_size += c->sector_size;
 226                         c->free_size -= c->sector_size;
 227                         bad_blocks++;
 228                         break;
 229                 default:
 230                         printk(KERN_WARNING "jffs2_scan_medium(): unknown block state\n");
 231                         BUG();
 232                 }
 233         }
 234
 235         /* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
 236         if (c->nextblock && (c->nextblock->dirty_size)) {
 237                 c->nextblock->wasted_size += c->nextblock->dirty_size;
 238                 c->wasted_size += c->nextblock->dirty_size;
 239                 c->dirty_size -= c->nextblock->dirty_size;
 240                 c->nextblock->dirty_size = 0;
 241         }
 242 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 243         if (!jffs2_can_mark_obsolete(c) && c->wbuf_pagesize && c->nextblock && (c->nextblock->free_size % c->wbuf_pagesize)) {
 244                 /* If we're going to start writing into a block which already
 245                    contains data, and the end of the data isn't page-aligned,
 246                    skip a little and align it. */
 247
 248                 uint32_t skip = c->nextblock->free_size % c->wbuf_pagesize;
 249
 250                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): Skipping %d bytes in nextblock to ensure page alignment\n",
 251                           skip));
 252                 jffs2_prealloc_raw_node_refs(c, c->nextblock, 1);
 253                 jffs2_scan_dirty_space(c, c->nextblock, skip);
 254         }
 255 #endif
 256         if (c->nr_erasing_blocks) {
 257                 if ( !c->used_size && ((c->nr_free_blocks+empty_blocks+bad_blocks)!= c->nr_blocks || bad_blocks == c->nr_blocks) ) {
 258                         printk(KERN_NOTICE "Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
 259                         printk(KERN_NOTICE "empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",empty_blocks,bad_blocks,c->nr_blocks);
 260                         ret = -EIO;
 261                         goto out;
 262                 }
 263                 jffs2_erase_pending_trigger(c);
 264         }
 265         ret = 0;
 266  out:
 267         if (buf_size)
 268                 kfree(flashbuf);
 269 #ifndef __ECOS
 270         else
 271                 c->mtd->unpoint(c->mtd, 0, c->mtd->size);
 272 #endif
 273         if (s)
 274                 kfree(s);
 275
 276         return ret;
 277 }
 278
 279 static int jffs2_fill_scan_buf(struct jffs2_sb_info *c, void *buf,
 280                                uint32_t ofs, uint32_t len)
 281 {
 282         int ret;
 283         size_t retlen;
 284
 285         ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
 286         if (ret) {
 287                 D1(printk(KERN_WARNING "mtd->read(0x%x bytes from 0x%x) returned %d\n", len, ofs, ret));
 288                 return ret;
 289         }
 290         if (retlen < len) {
 291                 D1(printk(KERN_WARNING "Read at 0x%x gave only 0x%zx bytes\n", ofs, retlen));
 292                 return -EIO;
 293         }
 294         return 0;
 295 }
 296
 297 int jffs2_scan_classify_jeb(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
 298 {
 299         if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size
 300             && (!jeb->first_node || !ref_next(jeb->first_node)) )
 301                 return BLK_STATE_CLEANMARKER;
 302
 303         /* move blocks with max 4 byte dirty space to cleanlist */
 304         else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
 305                 c->dirty_size -= jeb->dirty_size;
 306                 c->wasted_size += jeb->dirty_size;
 307                 jeb->wasted_size += jeb->dirty_size;
 308                 jeb->dirty_size = 0;
 309                 return BLK_STATE_CLEAN;
 310         } else if (jeb->used_size || jeb->unchecked_size)
 311                 return BLK_STATE_PARTDIRTY;
 312         else
 313                 return BLK_STATE_ALLDIRTY;
 314 }
 315
 316 #ifdef CONFIG_JFFS2_FS_XATTR
 317 static int jffs2_scan_xattr_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 318                                  struct jffs2_raw_xattr *rx, uint32_t ofs,
 319                                  struct jffs2_summary *s)
 320 {
 321         struct jffs2_xattr_datum *xd;
 322         uint32_t xid, version, totlen, crc;
 323         int err;
 324
 325         crc = crc32(0, rx, sizeof(struct jffs2_raw_xattr) - 4);
 326         if (crc != je32_to_cpu(rx->node_crc)) {
 327                 JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
 328                               ofs, je32_to_cpu(rx->node_crc), crc);
 329                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
 330                         return err;
 331                 return 0;
 332         }
 333
 334         xid = je32_to_cpu(rx->xid);
 335         version = je32_to_cpu(rx->version);
 336
 337         totlen = PAD(sizeof(struct jffs2_raw_xattr)
 338                         + rx->name_len + 1 + je16_to_cpu(rx->value_len));
 339         if (totlen != je32_to_cpu(rx->totlen)) {
 340                 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%u\n",
 341                               ofs, je32_to_cpu(rx->totlen), totlen);
 342                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
 343                         return err;
 344                 return 0;
 345         }
 346
 347         xd = jffs2_setup_xattr_datum(c, xid, version);
 348         if (IS_ERR(xd))
 349                 return PTR_ERR(xd);
 350
 351         if (xd->version > version) {
 352                 struct jffs2_raw_node_ref *raw
 353                         = jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, NULL);
 354                 raw->next_in_ino = xd->node->next_in_ino;
 355                 xd->node->next_in_ino = raw;
 356         } else {
 357                 xd->version = version;
 358                 xd->xprefix = rx->xprefix;
 359                 xd->name_len = rx->name_len;
 360                 xd->value_len = je16_to_cpu(rx->value_len);
 361                 xd->data_crc = je32_to_cpu(rx->data_crc);
 362
 363                 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, (void *)xd);
 364         }
 365
 366         if (jffs2_sum_active())
 367                 jffs2_sum_add_xattr_mem(s, rx, ofs - jeb->offset);
 368         dbg_xattr("scaning xdatum at %#08x (xid=%u, version=%u)\n",
 369                   ofs, xd->xid, xd->version);
 370         return 0;
 371 }
 372
 373 static int jffs2_scan_xref_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 374                                 struct jffs2_raw_xref *rr, uint32_t ofs,
 375                                 struct jffs2_summary *s)
 376 {
 377         struct jffs2_xattr_ref *ref;
 378         uint32_t crc;
 379         int err;
 380
 381         crc = crc32(0, rr, sizeof(*rr) - 4);
 382         if (crc != je32_to_cpu(rr->node_crc)) {
 383                 JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
 384                               ofs, je32_to_cpu(rr->node_crc), crc);
 385                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rr->totlen)))))
 386                         return err;
 387                 return 0;
 388         }
 389
 390         if (PAD(sizeof(struct jffs2_raw_xref)) != je32_to_cpu(rr->totlen)) {
 391                 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%zd\n",
 392                               ofs, je32_to_cpu(rr->totlen),
 393                               PAD(sizeof(struct jffs2_raw_xref)));
 394                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rr->totlen))))
 395                         return err;
 396                 return 0;
 397         }
 398
 399         ref = jffs2_alloc_xattr_ref();
 400         if (!ref)
 401                 return -ENOMEM;
 402
 403         /* BEFORE jffs2_build_xattr_subsystem() called,
 404          * and AFTER xattr_ref is marked as a dead xref,
 405          * ref->xid is used to store 32bit xid, xd is not used
 406          * ref->ino is used to store 32bit inode-number, ic is not used
 407          * Thoes variables are declared as union, thus using those
 408          * are exclusive. In a similar way, ref->next is temporarily
 409          * used to chain all xattr_ref object. It's re-chained to
 410          * jffs2_inode_cache in jffs2_build_xattr_subsystem() correctly.
 411          */
 412         ref->ino = je32_to_cpu(rr->ino);
 413         ref->xid = je32_to_cpu(rr->xid);
 414         ref->xseqno = je32_to_cpu(rr->xseqno);
 415         if (ref->xseqno > c->highest_xseqno)
 416                 c->highest_xseqno = (ref->xseqno & ~XREF_DELETE_MARKER);
 417         ref->next = c->xref_temp;
 418         c->xref_temp = ref;
 419
 420         jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(rr->totlen)), (void *)ref);
 421
 422         if (jffs2_sum_active())
 423                 jffs2_sum_add_xref_mem(s, rr, ofs - jeb->offset);
 424         dbg_xattr("scan xref at %#08x (xid=%u, ino=%u)\n",
 425                   ofs, ref->xid, ref->ino);
 426         return 0;
 427 }
 428 #endif
 429
 430 /* Called with 'buf_size == 0' if buf is in fact a pointer _directly_ into
 431    the flash, XIP-style */
 432 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 433                                   unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) {
 434         struct jffs2_unknown_node *node;
 435         struct jffs2_unknown_node crcnode;
 436         uint32_t ofs, prevofs;
 437         uint32_t hdr_crc, buf_ofs, buf_len;
 438         int err;
 439         int noise = 0;
 440
 441
 442 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 443         int cleanmarkerfound = 0;
 444 #endif
 445
 446         ofs = jeb->offset;
 447         prevofs = jeb->offset - 1;
 448
 449         D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs));
 450
 451 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 452         if (jffs2_cleanmarker_oob(c)) {
 453                 int ret;
 454
 455                 if (c->mtd->block_isbad(c->mtd, jeb->offset))
 456                         return BLK_STATE_BADBLOCK;
 457
 458                 ret = jffs2_check_nand_cleanmarker(c, jeb);
 459                 D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n",ret));
 460
 461                 /* Even if it's not found, we still scan to see
 462                    if the block is empty. We use this information
 463                    to decide whether to erase it or not. */
 464                 switch (ret) {
 465                 case 0:         cleanmarkerfound = 1; break;
 466                 case 1:         break;
 467                 default:        return ret;
 468                 }
 469         }
 470 #endif
 471
 472         if (jffs2_sum_active()) {
 473                 struct jffs2_sum_marker *sm;
 474                 void *sumptr = NULL;
 475                 uint32_t sumlen;
 476
 477                 if (!buf_size) {
 478                         /* XIP case. Just look, point at the summary if it's there */
 479                         sm = (void *)buf + c->sector_size - sizeof(*sm);
 480                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
 481                                 sumptr = buf + je32_to_cpu(sm->offset);
 482                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
 483                         }
 484                 } else {
 485                         /* If NAND flash, read a whole page of it. Else just the end */
 486                         if (c->wbuf_pagesize)
 487                                 buf_len = c->wbuf_pagesize;
 488                         else
 489                                 buf_len = sizeof(*sm);
 490
 491                         /* Read as much as we want into the _end_ of the preallocated buffer */
 492                         err = jffs2_fill_scan_buf(c, buf + buf_size - buf_len,
 493                                                   jeb->offset + c->sector_size - buf_len,
 494                                                   buf_len);
 495                         if (err)
 496                                 return err;
 497
 498                         sm = (void *)buf + buf_size - sizeof(*sm);
 499                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
 500                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
 501                                 sumptr = buf + buf_size - sumlen;
 502
 503                                 /* Now, make sure the summary itself is available */
 504                                 if (sumlen > buf_size) {
 505                                         /* Need to kmalloc for this. */
 506                                         sumptr = kmalloc(sumlen, GFP_KERNEL);
 507                                         if (!sumptr)
 508                                                 return -ENOMEM;
 509                                         memcpy(sumptr + sumlen - buf_len, buf + buf_size - buf_len, buf_len);
 510                                 }
 511                                 if (buf_len < sumlen) {
 512                                         /* Need to read more so that the entire summary node is present */
 513                                         err = jffs2_fill_scan_buf(c, sumptr,
 514                                                                   jeb->offset + c->sector_size - sumlen,
 515                                                                   sumlen - buf_len);
 516                                         if (err)
 517                                                 return err;
 518                                 }
 519                         }
 520
 521                 }
 522
 523                 if (sumptr) {
 524                         err = jffs2_sum_scan_sumnode(c, jeb, sumptr, sumlen, &pseudo_random);
 525
 526                         if (buf_size && sumlen > buf_size)
 527                                 kfree(sumptr);
 528                         /* If it returns with a real error, bail.
 529                            If it returns positive, that's a block classification
 530                            (i.e. BLK_STATE_xxx) so return that too.
 531                            If it returns zero, fall through to full scan. */
 532                         if (err)
 533                                 return err;
 534                 }
 535         }
 536
 537         buf_ofs = jeb->offset;
 538
 539         if (!buf_size) {
 540                 /* This is the XIP case -- we're reading _directly_ from the flash chip */
 541                 buf_len = c->sector_size;
 542         } else {
 543                 buf_len = EMPTY_SCAN_SIZE(c->sector_size);
 544                 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
 545                 if (err)
 546                         return err;
 547         }
 548
 549         /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
 550         ofs = 0;
 551
 552         /* Scan only 4KiB of 0xFF before declaring it's empty */
 553         while(ofs < EMPTY_SCAN_SIZE(c->sector_size) && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
 554                 ofs += 4;
 555
 556         if (ofs == EMPTY_SCAN_SIZE(c->sector_size)) {
 557 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 558                 if (jffs2_cleanmarker_oob(c)) {
 559                         /* scan oob, take care of cleanmarker */
 560                         int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
 561                         D2(printk(KERN_NOTICE "jffs2_check_oob_empty returned %d\n",ret));
 562                         switch (ret) {
 563                         case 0:         return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
 564                         case 1:         return BLK_STATE_ALLDIRTY;
 565                         default:        return ret;
 566                         }
 567                 }
 568 #endif
 569                 D1(printk(KERN_DEBUG "Block at 0x%08x is empty (erased)\n", jeb->offset));
 570                 if (c->cleanmarker_size == 0)
 571                         return BLK_STATE_CLEANMARKER;   /* don't bother with re-erase */
 572                 else
 573                         return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
 574         }
 575         if (ofs) {
 576                 D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset,
 577                           jeb->offset + ofs));
 578                 if ((err = jffs2_prealloc_raw_node_refs(c, jeb, 1)))
 579                         return err;
 580                 if ((err = jffs2_scan_dirty_space(c, jeb, ofs)))
 581                         return err;
 582         }
 583
 584         /* Now ofs is a complete physical flash offset as it always was... */
 585         ofs += jeb->offset;
 586
 587         noise = 10;
 588
 589         dbg_summary("no summary found in jeb 0x%08x. Apply original scan.\n",jeb->offset);
 590
 591 scan_more:
 592         while(ofs < jeb->offset + c->sector_size) {
 593
 594                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 595
 596                 /* Make sure there are node refs available for use */
 597                 err = jffs2_prealloc_raw_node_refs(c, jeb, 2);
 598                 if (err)
 599                         return err;
 600
 601                 cond_resched();
 602
 603                 if (ofs & 3) {
 604                         printk(KERN_WARNING "Eep. ofs 0x%08x not word-aligned!\n", ofs);
 605                         ofs = PAD(ofs);
 606                         continue;
 607                 }
 608                 if (ofs == prevofs) {
 609                         printk(KERN_WARNING "ofs 0x%08x has already been seen. Skipping\n", ofs);
 610                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 611                                 return err;
 612                         ofs += 4;
 613                         continue;
 614                 }
 615                 prevofs = ofs;
 616
 617                 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
 618                         D1(printk(KERN_DEBUG "Fewer than %zd bytes left to end of block. (%x+%x<%x+%zx) Not reading\n", sizeof(struct jffs2_unknown_node),
 619                                   jeb->offset, c->sector_size, ofs, sizeof(*node)));
 620                         if ((err = jffs2_scan_dirty_space(c, jeb, (jeb->offset + c->sector_size)-ofs)))
 621                                 return err;
 622                         break;
 623                 }
 624
 625                 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
 626                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 627                         D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
 628                                   sizeof(struct jffs2_unknown_node), buf_len, ofs));
 629                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 630                         if (err)
 631                                 return err;
 632                         buf_ofs = ofs;
 633                 }
 634
 635                 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
 636
 637                 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
 638                         uint32_t inbuf_ofs;
 639                         uint32_t empty_start, scan_end;
 640
 641                         empty_start = ofs;
 642                         ofs += 4;
 643                         scan_end = min_t(uint32_t, EMPTY_SCAN_SIZE(c->sector_size)/8, buf_len);
 644
 645                         D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs));
 646                 more_empty:
 647                         inbuf_ofs = ofs - buf_ofs;
 648                         while (inbuf_ofs < scan_end) {
 649                                 if (unlikely(*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff)) {
 650                                         printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n",
 651                                                empty_start, ofs);
 652                                         if ((err = jffs2_scan_dirty_space(c, jeb, ofs-empty_start)))
 653                                                 return err;
 654                                         goto scan_more;
 655                                 }
 656
 657                                 inbuf_ofs+=4;
 658                                 ofs += 4;
 659                         }
 660                         /* Ran off end. */
 661                         D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs));
 662
 663                         /* If we're only checking the beginning of a block with a cleanmarker,
 664                            bail now */
 665                         if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&
 666                             c->cleanmarker_size && !jeb->dirty_size && !ref_next(jeb->first_node)) {
 667                                 D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE(c->sector_size)));
 668                                 return BLK_STATE_CLEANMARKER;
 669                         }
 670                         if (!buf_size && (scan_end != buf_len)) {/* XIP/point case */
 671                                 scan_end = buf_len;
 672                                 goto more_empty;
 673                         }
 674
 675                         /* See how much more there is to read in this eraseblock... */
 676                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 677                         if (!buf_len) {
 678                                 /* No more to read. Break out of main loop without marking
 679                                    this range of empty space as dirty (because it's not) */
 680                                 D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block. Treating as free_space\n",
 681                                           empty_start));
 682                                 break;
 683                         }
 684                         /* point never reaches here */
 685                         scan_end = buf_len;
 686                         D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs));
 687                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 688                         if (err)
 689                                 return err;
 690                         buf_ofs = ofs;
 691                         goto more_empty;
 692                 }
 693
 694                 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
 695                         printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n", ofs);
 696                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 697                                 return err;
 698                         ofs += 4;
 699                         continue;
 700                 }
 701                 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
 702                         D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs));
 703                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 704                                 return err;
 705                         ofs += 4;
 706                         continue;
 707                 }
 708                 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
 709                         printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08x\n", ofs);
 710                         printk(KERN_WARNING "You cannot use older JFFS2 filesystems with newer kernels\n");
 711                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 712                                 return err;
 713                         ofs += 4;
 714                         continue;
 715                 }
 716                 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
 717                         /* OK. We're out of possibilities. Whinge and move on */
 718                         noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n",
 719                                      JFFS2_MAGIC_BITMASK, ofs,
 720                                      je16_to_cpu(node->magic));
 721                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 722                                 return err;
 723                         ofs += 4;
 724                         continue;
 725                 }
 726                 /* We seem to have a node of sorts. Check the CRC */
 727                 crcnode.magic = node->magic;
 728                 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
 729                 crcnode.totlen = node->totlen;
 730                 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
 731
 732                 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
 733                         noisy_printk(&noise, "jffs2_scan_eraseblock(): Node at 0x%08x {0x%04x, 0x%04x, 0x%08x) has invalid CRC 0x%08x (calculated 0x%08x)\n",
 734                                      ofs, je16_to_cpu(node->magic),
 735                                      je16_to_cpu(node->nodetype),
 736                                      je32_to_cpu(node->totlen),
 737                                      je32_to_cpu(node->hdr_crc),
 738                                      hdr_crc);
 739                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 740                                 return err;
 741                         ofs += 4;
 742                         continue;
 743                 }
 744
 745                 if (ofs + je32_to_cpu(node->totlen) > jeb->offset + c->sector_size) {
 746                         /* Eep. Node goes over the end of the erase block. */
 747                         printk(KERN_WARNING "Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
 748                                ofs, je32_to_cpu(node->totlen));
 749                         printk(KERN_WARNING "Perhaps the file system was created with the wrong erase size?\n");
 750                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 751                                 return err;
 752                         ofs += 4;
 753                         continue;
 754                 }
 755
 756                 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
 757                         /* Wheee. This is an obsoleted node */
 758                         D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs));
 759                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 760                                 return err;
 761                         ofs += PAD(je32_to_cpu(node->totlen));
 762                         continue;
 763                 }
 764
 765                 switch(je16_to_cpu(node->nodetype)) {
 766                 case JFFS2_NODETYPE_INODE:
 767                         if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
 768                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 769                                 D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
 770                                           sizeof(struct jffs2_raw_inode), buf_len, ofs));
 771                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 772                                 if (err)
 773                                         return err;
 774                                 buf_ofs = ofs;
 775                                 node = (void *)buf;
 776                         }
 777                         err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs, s);
 778                         if (err) return err;
 779                         ofs += PAD(je32_to_cpu(node->totlen));
 780                         break;
 781
 782                 case JFFS2_NODETYPE_DIRENT:
 783                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 784                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 785                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
 786                                           je32_to_cpu(node->totlen), buf_len, ofs));
 787                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 788                                 if (err)
 789                                         return err;
 790                                 buf_ofs = ofs;
 791                                 node = (void *)buf;
 792                         }
 793                         err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs, s);
 794                         if (err) return err;
 795                         ofs += PAD(je32_to_cpu(node->totlen));
 796                         break;
 797
 798 #ifdef CONFIG_JFFS2_FS_XATTR
 799                 case JFFS2_NODETYPE_XATTR:
 800                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 801                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 802                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (xattr node)"
 803                                           " left to end of buf. Reading 0x%x at 0x%08x\n",
 804                                           je32_to_cpu(node->totlen), buf_len, ofs));
 805                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 806                                 if (err)
 807                                         return err;
 808                                 buf_ofs = ofs;
 809                                 node = (void *)buf;
 810                         }
 811                         err = jffs2_scan_xattr_node(c, jeb, (void *)node, ofs, s);
 812                         if (err)
 813                                 return err;
 814                         ofs += PAD(je32_to_cpu(node->totlen));
 815                         break;
 816                 case JFFS2_NODETYPE_XREF:
 817                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 818                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 819                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (xref node)"
 820                                           " left to end of buf. Reading 0x%x at 0x%08x\n",
 821                                           je32_to_cpu(node->totlen), buf_len, ofs));
 822                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 823                                 if (err)
 824                                         return err;
 825                                 buf_ofs = ofs;
 826                                 node = (void *)buf;
 827                         }
 828                         err = jffs2_scan_xref_node(c, jeb, (void *)node, ofs, s);
 829                         if (err)
 830                                 return err;
 831                         ofs += PAD(je32_to_cpu(node->totlen));
 832                         break;
 833 #endif  /* CONFIG_JFFS2_FS_XATTR */
 834
 835                 case JFFS2_NODETYPE_CLEANMARKER:
 836                         D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs));
 837                         if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
 838                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n",
 839                                        ofs, je32_to_cpu(node->totlen), c->cleanmarker_size);
 840                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
 841                                         return err;
 842                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 843                         } else if (jeb->first_node) {
 844                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n", ofs, jeb->offset);
 845                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
 846                                         return err;
 847                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 848                         } else {
 849                                 jffs2_link_node_ref(c, jeb, ofs | REF_NORMAL, c->cleanmarker_size, NULL);
 850
 851                                 ofs += PAD(c->cleanmarker_size);
 852                         }
 853                         break;
 854
 855                 case JFFS2_NODETYPE_PADDING:
 856                         if (jffs2_sum_active())
 857                                 jffs2_sum_add_padding_mem(s, je32_to_cpu(node->totlen));
 858                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 859                                 return err;
 860                         ofs += PAD(je32_to_cpu(node->totlen));
 861                         break;
 862
 863                 default:
 864                         switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
 865                         case JFFS2_FEATURE_ROCOMPAT:
 866                                 printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 867                                 c->flags |= JFFS2_SB_FLAG_RO;
 868                                 if (!(jffs2_is_readonly(c)))
 869                                         return -EROFS;
 870                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 871                                         return err;
 872                                 ofs += PAD(je32_to_cpu(node->totlen));
 873                                 break;
 874
 875                         case JFFS2_FEATURE_INCOMPAT:
 876                                 printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 877                                 return -EINVAL;
 878
 879                         case JFFS2_FEATURE_RWCOMPAT_DELETE:
 880                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 881                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 882                                         return err;
 883                                 ofs += PAD(je32_to_cpu(node->totlen));
 884                                 break;
 885
 886                         case JFFS2_FEATURE_RWCOMPAT_COPY: {
 887                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 888
 889                                 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(node->totlen)), NULL);
 890
 891                                 /* We can't summarise nodes we don't grok */
 892                                 jffs2_sum_disable_collecting(s);
 893                                 ofs += PAD(je32_to_cpu(node->totlen));
 894                                 break;
 895                                 }
 896                         }
 897                 }
 898         }
 899
 900         if (jffs2_sum_active()) {
 901                 if (PAD(s->sum_size + JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size) {
 902                         dbg_summary("There is not enough space for "
 903                                 "summary information, disabling for this jeb!\n");
 904                         jffs2_sum_disable_collecting(s);
 905                 }
 906         }
 907
 908         D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x, wasted 0x%08x\n",
 909                   jeb->offset,jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size, jeb->wasted_size));
 910
 911         /* mark_node_obsolete can add to wasted !! */
 912         if (jeb->wasted_size) {
 913                 jeb->dirty_size += jeb->wasted_size;
 914                 c->dirty_size += jeb->wasted_size;
 915                 c->wasted_size -= jeb->wasted_size;
 916                 jeb->wasted_size = 0;
 917         }
 918
 919         return jffs2_scan_classify_jeb(c, jeb);
 920 }
 921
 922 struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
 923 {
 924         struct jffs2_inode_cache *ic;
 925
 926         ic = jffs2_get_ino_cache(c, ino);
 927         if (ic)
 928                 return ic;
 929
 930         if (ino > c->highest_ino)
 931                 c->highest_ino = ino;
 932
 933         ic = jffs2_alloc_inode_cache();
 934         if (!ic) {
 935                 printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n");
 936                 return NULL;
 937         }
 938         memset(ic, 0, sizeof(*ic));
 939
 940         ic->ino = ino;
 941         ic->nodes = (void *)ic;
 942         jffs2_add_ino_cache(c, ic);
 943         if (ino == 1)
 944                 ic->pino_nlink = 1;
 945         return ic;
 946 }
 947
 948 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 949                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s)
 950 {
 951         struct jffs2_inode_cache *ic;
 952         uint32_t crc, ino = je32_to_cpu(ri->ino);
 953
 954         D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs));
 955
 956         /* We do very little here now. Just check the ino# to which we should attribute
 957            this node; we can do all the CRC checking etc. later. There's a tradeoff here --
 958            we used to scan the flash once only, reading everything we want from it into
 959            memory, then building all our in-core data structures and freeing the extra
 960            information. Now we allow the first part of the mount to complete a lot quicker,
 961            but we have to go _back_ to the flash in order to finish the CRC checking, etc.
 962            Which means that the _full_ amount of time to get to proper write mode with GC
 963            operational may actually be _longer_ than before. Sucks to be me. */
 964
 965         /* Check the node CRC in any case. */
 966         crc = crc32(0, ri, sizeof(*ri)-8);
 967         if (crc != je32_to_cpu(ri->node_crc)) {
 968                 printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on "
 969                        "node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 970                        ofs, je32_to_cpu(ri->node_crc), crc);
 971                 /*
 972                  * We believe totlen because the CRC on the node
 973                  * _header_ was OK, just the node itself failed.
 974                  */
 975                 return jffs2_scan_dirty_space(c, jeb,
 976                                               PAD(je32_to_cpu(ri->totlen)));
 977         }
 978
 979         ic = jffs2_get_ino_cache(c, ino);
 980         if (!ic) {
 981                 ic = jffs2_scan_make_ino_cache(c, ino);
 982                 if (!ic)
 983                         return -ENOMEM;
 984         }
 985
 986         /* Wheee. It worked */
 987         jffs2_link_node_ref(c, jeb, ofs | REF_UNCHECKED, PAD(je32_to_cpu(ri->totlen)), ic);
 988
 989         D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
 990                   je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
 991                   je32_to_cpu(ri->offset),
 992                   je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize)));
 993
 994         pseudo_random += je32_to_cpu(ri->version);
 995
 996         if (jffs2_sum_active()) {
 997                 jffs2_sum_add_inode_mem(s, ri, ofs - jeb->offset);
 998         }
 999
1000         return 0;
1001 }
1002
1003 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
1004                                   struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s)
1005 {
1006         struct jffs2_full_dirent *fd;
1007         struct jffs2_inode_cache *ic;
1008         uint32_t checkedlen;
1009         uint32_t crc;
1010         int err;
1011
1012         D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs));
1013
1014         /* We don't get here unless the node is still valid, so we don't have to
1015            mask in the ACCURATE bit any more. */
1016         crc = crc32(0, rd, sizeof(*rd)-8);
1017
1018         if (crc != je32_to_cpu(rd->node_crc)) {
1019                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1020                        ofs, je32_to_cpu(rd->node_crc), crc);
1021                 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
1022                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1023                         return err;
1024                 return 0;
1025         }
1026
1027         pseudo_random += je32_to_cpu(rd->version);
1028
1029         /* Should never happen. Did. (OLPC trac #4184)*/
1030         checkedlen = strnlen(rd->name, rd->nsize);
1031         if (checkedlen < rd->nsize) {
1032                 printk(KERN_ERR "Dirent at %08x has zeroes in name. Truncating to %d chars\n",
1033                        ofs, checkedlen);
1034         }
1035         fd = jffs2_alloc_full_dirent(checkedlen+1);
1036         if (!fd) {
1037                 return -ENOMEM;
1038         }
1039         memcpy(&fd->name, rd->name, checkedlen);
1040         fd->name[checkedlen] = 0;
1041
1042         crc = crc32(0, fd->name, rd->nsize);
1043         if (crc != je32_to_cpu(rd->name_crc)) {
1044                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1045                        ofs, je32_to_cpu(rd->name_crc), crc);
1046                 D1(printk(KERN_NOTICE "Name for which CRC failed is (now) '%s', ino #%d\n", fd->name, je32_to_cpu(rd->ino)));
1047                 jffs2_free_full_dirent(fd);
1048                 /* FIXME: Why do we believe totlen? */
1049                 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
1050                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1051                         return err;
1052                 return 0;
1053         }
1054         ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
1055         if (!ic) {
1056                 jffs2_free_full_dirent(fd);
1057                 return -ENOMEM;
1058         }
1059
1060         fd->raw = jffs2_link_node_ref(c, jeb, ofs | dirent_node_state(rd),
1061                                       PAD(je32_to_cpu(rd->totlen)), ic);
1062
1063         fd->next = NULL;
1064         fd->version = je32_to_cpu(rd->version);
1065         fd->ino = je32_to_cpu(rd->ino);
1066         fd->nhash = full_name_hash(fd->name, checkedlen);
1067         fd->type = rd->type;
1068         jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
1069
1070         if (jffs2_sum_active()) {
1071                 jffs2_sum_add_dirent_mem(s, rd, ofs - jeb->offset);
1072         }
1073
1074         return 0;
1075 }
1076
1077 static int count_list(struct list_head *l)
1078 {
1079         uint32_t count = 0;
1080         struct list_head *tmp;
1081
1082         list_for_each(tmp, l) {
1083                 count++;
1084         }
1085         return count;
1086 }
1087
1088 /* Note: This breaks if list_empty(head). I don't care. You
1089    might, if you copy this code and use it elsewhere :) */
1090 static void rotate_list(struct list_head *head, uint32_t count)
1091 {
1092         struct list_head *n = head->next;
1093
1094         list_del(head);
1095         while(count--) {
1096                 n = n->next;
1097         }
1098         list_add(head, n);
1099 }
1100
1101 void jffs2_rotate_lists(struct jffs2_sb_info *c)
1102 {
1103         uint32_t x;
1104         uint32_t rotateby;
1105
1106         x = count_list(&c->clean_list);
1107         if (x) {
1108                 rotateby = pseudo_random % x;
1109                 rotate_list((&c->clean_list), rotateby);
1110         }
1111
1112         x = count_list(&c->very_dirty_list);
1113         if (x) {
1114                 rotateby = pseudo_random % x;
1115                 rotate_list((&c->very_dirty_list), rotateby);
1116         }
1117
1118         x = count_list(&c->dirty_list);
1119         if (x) {
1120                 rotateby = pseudo_random % x;
1121                 rotate_list((&c->dirty_list), rotateby);
1122         }
1123
1124         x = count_list(&c->erasable_list);
1125         if (x) {
1126                 rotateby = pseudo_random % x;
1127                 rotate_list((&c->erasable_list), rotateby);
1128         }
1129
1130         if (c->nr_erasing_blocks) {
1131                 rotateby = pseudo_random % c->nr_erasing_blocks;
1132                 rotate_list((&c->erase_pending_list), rotateby);
1133         }
1134
1135         if (c->nr_free_blocks) {
1136                 rotateby = pseudo_random % c->nr_free_blocks;
1137                 rotate_list((&c->free_list), rotateby);
1138         }
1139 }