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 <[email protected]>
   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 256
  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                         JFFS2_WARNING("Can't allocate memory for summary\n");
 134                         ret = -ENOMEM;
 135                         goto out;
 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                                                 goto out;
 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                                         goto out;
 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                 spin_lock(&c->erase_completion_lock);
 264                 jffs2_garbage_collect_trigger(c);
 265                 spin_unlock(&c->erase_completion_lock);
 266         }
 267         ret = 0;
 268  out:
 269         if (buf_size)
 270                 kfree(flashbuf);
 271 #ifndef __ECOS
 272         else
 273                 c->mtd->unpoint(c->mtd, 0, c->mtd->size);
 274 #endif
 275         if (s)
 276                 kfree(s);
 277
 278         return ret;
 279 }
 280
 281 static int jffs2_fill_scan_buf(struct jffs2_sb_info *c, void *buf,
 282                                uint32_t ofs, uint32_t len)
 283 {
 284         int ret;
 285         size_t retlen;
 286
 287         ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
 288         if (ret) {
 289                 D1(printk(KERN_WARNING "mtd->read(0x%x bytes from 0x%x) returned %d\n", len, ofs, ret));
 290                 return ret;
 291         }
 292         if (retlen < len) {
 293                 D1(printk(KERN_WARNING "Read at 0x%x gave only 0x%zx bytes\n", ofs, retlen));
 294                 return -EIO;
 295         }
 296         return 0;
 297 }
 298
 299 int jffs2_scan_classify_jeb(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
 300 {
 301         if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size
 302             && (!jeb->first_node || !ref_next(jeb->first_node)) )
 303                 return BLK_STATE_CLEANMARKER;
 304
 305         /* move blocks with max 4 byte dirty space to cleanlist */
 306         else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
 307                 c->dirty_size -= jeb->dirty_size;
 308                 c->wasted_size += jeb->dirty_size;
 309                 jeb->wasted_size += jeb->dirty_size;
 310                 jeb->dirty_size = 0;
 311                 return BLK_STATE_CLEAN;
 312         } else if (jeb->used_size || jeb->unchecked_size)
 313                 return BLK_STATE_PARTDIRTY;
 314         else
 315                 return BLK_STATE_ALLDIRTY;
 316 }
 317
 318 #ifdef CONFIG_JFFS2_FS_XATTR
 319 static int jffs2_scan_xattr_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 320                                  struct jffs2_raw_xattr *rx, uint32_t ofs,
 321                                  struct jffs2_summary *s)
 322 {
 323         struct jffs2_xattr_datum *xd;
 324         uint32_t xid, version, totlen, crc;
 325         int err;
 326
 327         crc = crc32(0, rx, sizeof(struct jffs2_raw_xattr) - 4);
 328         if (crc != je32_to_cpu(rx->node_crc)) {
 329                 JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
 330                               ofs, je32_to_cpu(rx->node_crc), crc);
 331                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
 332                         return err;
 333                 return 0;
 334         }
 335
 336         xid = je32_to_cpu(rx->xid);
 337         version = je32_to_cpu(rx->version);
 338
 339         totlen = PAD(sizeof(struct jffs2_raw_xattr)
 340                         + rx->name_len + 1 + je16_to_cpu(rx->value_len));
 341         if (totlen != je32_to_cpu(rx->totlen)) {
 342                 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%u\n",
 343                               ofs, je32_to_cpu(rx->totlen), totlen);
 344                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
 345                         return err;
 346                 return 0;
 347         }
 348
 349         xd = jffs2_setup_xattr_datum(c, xid, version);
 350         if (IS_ERR(xd))
 351                 return PTR_ERR(xd);
 352
 353         if (xd->version > version) {
 354                 struct jffs2_raw_node_ref *raw
 355                         = jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, NULL);
 356                 raw->next_in_ino = xd->node->next_in_ino;
 357                 xd->node->next_in_ino = raw;
 358         } else {
 359                 xd->version = version;
 360                 xd->xprefix = rx->xprefix;
 361                 xd->name_len = rx->name_len;
 362                 xd->value_len = je16_to_cpu(rx->value_len);
 363                 xd->data_crc = je32_to_cpu(rx->data_crc);
 364
 365                 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, (void *)xd);
 366         }
 367
 368         if (jffs2_sum_active())
 369                 jffs2_sum_add_xattr_mem(s, rx, ofs - jeb->offset);
 370         dbg_xattr("scaning xdatum at %#08x (xid=%u, version=%u)\n",
 371                   ofs, xd->xid, xd->version);
 372         return 0;
 373 }
 374
 375 static int jffs2_scan_xref_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 376                                 struct jffs2_raw_xref *rr, uint32_t ofs,
 377                                 struct jffs2_summary *s)
 378 {
 379         struct jffs2_xattr_ref *ref;
 380         uint32_t crc;
 381         int err;
 382
 383         crc = crc32(0, rr, sizeof(*rr) - 4);
 384         if (crc != je32_to_cpu(rr->node_crc)) {
 385                 JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
 386                               ofs, je32_to_cpu(rr->node_crc), crc);
 387                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rr->totlen)))))
 388                         return err;
 389                 return 0;
 390         }
 391
 392         if (PAD(sizeof(struct jffs2_raw_xref)) != je32_to_cpu(rr->totlen)) {
 393                 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%zd\n",
 394                               ofs, je32_to_cpu(rr->totlen),
 395                               PAD(sizeof(struct jffs2_raw_xref)));
 396                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rr->totlen))))
 397                         return err;
 398                 return 0;
 399         }
 400
 401         ref = jffs2_alloc_xattr_ref();
 402         if (!ref)
 403                 return -ENOMEM;
 404
 405         /* BEFORE jffs2_build_xattr_subsystem() called,
 406          * and AFTER xattr_ref is marked as a dead xref,
 407          * ref->xid is used to store 32bit xid, xd is not used
 408          * ref->ino is used to store 32bit inode-number, ic is not used
 409          * Thoes variables are declared as union, thus using those
 410          * are exclusive. In a similar way, ref->next is temporarily
 411          * used to chain all xattr_ref object. It's re-chained to
 412          * jffs2_inode_cache in jffs2_build_xattr_subsystem() correctly.
 413          */
 414         ref->ino = je32_to_cpu(rr->ino);
 415         ref->xid = je32_to_cpu(rr->xid);
 416         ref->xseqno = je32_to_cpu(rr->xseqno);
 417         if (ref->xseqno > c->highest_xseqno)
 418                 c->highest_xseqno = (ref->xseqno & ~XREF_DELETE_MARKER);
 419         ref->next = c->xref_temp;
 420         c->xref_temp = ref;
 421
 422         jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(rr->totlen)), (void *)ref);
 423
 424         if (jffs2_sum_active())
 425                 jffs2_sum_add_xref_mem(s, rr, ofs - jeb->offset);
 426         dbg_xattr("scan xref at %#08x (xid=%u, ino=%u)\n",
 427                   ofs, ref->xid, ref->ino);
 428         return 0;
 429 }
 430 #endif
 431
 432 /* Called with 'buf_size == 0' if buf is in fact a pointer _directly_ into
 433    the flash, XIP-style */
 434 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 435                                   unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) {
 436         struct jffs2_unknown_node *node;
 437         struct jffs2_unknown_node crcnode;
 438         uint32_t ofs, prevofs, max_ofs;
 439         uint32_t hdr_crc, buf_ofs, buf_len;
 440         int err;
 441         int noise = 0;
 442
 443
 444 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 445         int cleanmarkerfound = 0;
 446 #endif
 447
 448         ofs = jeb->offset;
 449         prevofs = jeb->offset - 1;
 450
 451         D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs));
 452
 453 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 454         if (jffs2_cleanmarker_oob(c)) {
 455                 int ret;
 456
 457                 if (c->mtd->block_isbad(c->mtd, jeb->offset))
 458                         return BLK_STATE_BADBLOCK;
 459
 460                 ret = jffs2_check_nand_cleanmarker(c, jeb);
 461                 D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n",ret));
 462
 463                 /* Even if it's not found, we still scan to see
 464                    if the block is empty. We use this information
 465                    to decide whether to erase it or not. */
 466                 switch (ret) {
 467                 case 0:         cleanmarkerfound = 1; break;
 468                 case 1:         break;
 469                 default:        return ret;
 470                 }
 471         }
 472 #endif
 473
 474         if (jffs2_sum_active()) {
 475                 struct jffs2_sum_marker *sm;
 476                 void *sumptr = NULL;
 477                 uint32_t sumlen;
 478
 479                 if (!buf_size) {
 480                         /* XIP case. Just look, point at the summary if it's there */
 481                         sm = (void *)buf + c->sector_size - sizeof(*sm);
 482                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
 483                                 sumptr = buf + je32_to_cpu(sm->offset);
 484                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
 485                         }
 486                 } else {
 487                         /* If NAND flash, read a whole page of it. Else just the end */
 488                         if (c->wbuf_pagesize)
 489                                 buf_len = c->wbuf_pagesize;
 490                         else
 491                                 buf_len = sizeof(*sm);
 492
 493                         /* Read as much as we want into the _end_ of the preallocated buffer */
 494                         err = jffs2_fill_scan_buf(c, buf + buf_size - buf_len,
 495                                                   jeb->offset + c->sector_size - buf_len,
 496                                                   buf_len);
 497                         if (err)
 498                                 return err;
 499
 500                         sm = (void *)buf + buf_size - sizeof(*sm);
 501                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
 502                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
 503                                 sumptr = buf + buf_size - sumlen;
 504
 505                                 /* Now, make sure the summary itself is available */
 506                                 if (sumlen > buf_size) {
 507                                         /* Need to kmalloc for this. */
 508                                         sumptr = kmalloc(sumlen, GFP_KERNEL);
 509                                         if (!sumptr)
 510                                                 return -ENOMEM;
 511                                         memcpy(sumptr + sumlen - buf_len, buf + buf_size - buf_len, buf_len);
 512                                 }
 513                                 if (buf_len < sumlen) {
 514                                         /* Need to read more so that the entire summary node is present */
 515                                         err = jffs2_fill_scan_buf(c, sumptr,
 516                                                                   jeb->offset + c->sector_size - sumlen,
 517                                                                   sumlen - buf_len);
 518                                         if (err)
 519                                                 return err;
 520                                 }
 521                         }
 522
 523                 }
 524
 525                 if (sumptr) {
 526                         err = jffs2_sum_scan_sumnode(c, jeb, sumptr, sumlen, &pseudo_random);
 527
 528                         if (buf_size && sumlen > buf_size)
 529                                 kfree(sumptr);
 530                         /* If it returns with a real error, bail.
 531                            If it returns positive, that's a block classification
 532                            (i.e. BLK_STATE_xxx) so return that too.
 533                            If it returns zero, fall through to full scan. */
 534                         if (err)
 535                                 return err;
 536                 }
 537         }
 538
 539         buf_ofs = jeb->offset;
 540
 541         if (!buf_size) {
 542                 /* This is the XIP case -- we're reading _directly_ from the flash chip */
 543                 buf_len = c->sector_size;
 544         } else {
 545                 buf_len = EMPTY_SCAN_SIZE(c->sector_size);
 546                 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
 547                 if (err)
 548                         return err;
 549         }
 550
 551         /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
 552         ofs = 0;
 553         max_ofs = EMPTY_SCAN_SIZE(c->sector_size);
 554         /* Scan only EMPTY_SCAN_SIZE of 0xFF before declaring it's empty */
 555         while(ofs < max_ofs && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
 556                 ofs += 4;
 557
 558         if (ofs == max_ofs) {
 559 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 560                 if (jffs2_cleanmarker_oob(c)) {
 561                         /* scan oob, take care of cleanmarker */
 562                         int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
 563                         D2(printk(KERN_NOTICE "jffs2_check_oob_empty returned %d\n",ret));
 564                         switch (ret) {
 565                         case 0:         return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
 566                         case 1:         return BLK_STATE_ALLDIRTY;
 567                         default:        return ret;
 568                         }
 569                 }
 570 #endif
 571                 D1(printk(KERN_DEBUG "Block at 0x%08x is empty (erased)\n", jeb->offset));
 572                 if (c->cleanmarker_size == 0)
 573                         return BLK_STATE_CLEANMARKER;   /* don't bother with re-erase */
 574                 else
 575                         return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
 576         }
 577         if (ofs) {
 578                 D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset,
 579                           jeb->offset + ofs));
 580                 if ((err = jffs2_prealloc_raw_node_refs(c, jeb, 1)))
 581                         return err;
 582                 if ((err = jffs2_scan_dirty_space(c, jeb, ofs)))
 583                         return err;
 584         }
 585
 586         /* Now ofs is a complete physical flash offset as it always was... */
 587         ofs += jeb->offset;
 588
 589         noise = 10;
 590
 591         dbg_summary("no summary found in jeb 0x%08x. Apply original scan.\n",jeb->offset);
 592
 593 scan_more:
 594         while(ofs < jeb->offset + c->sector_size) {
 595
 596                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 597
 598                 /* Make sure there are node refs available for use */
 599                 err = jffs2_prealloc_raw_node_refs(c, jeb, 2);
 600                 if (err)
 601                         return err;
 602
 603                 cond_resched();
 604
 605                 if (ofs & 3) {
 606                         printk(KERN_WARNING "Eep. ofs 0x%08x not word-aligned!\n", ofs);
 607                         ofs = PAD(ofs);
 608                         continue;
 609                 }
 610                 if (ofs == prevofs) {
 611                         printk(KERN_WARNING "ofs 0x%08x has already been seen. Skipping\n", ofs);
 612                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 613                                 return err;
 614                         ofs += 4;
 615                         continue;
 616                 }
 617                 prevofs = ofs;
 618
 619                 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
 620                         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),
 621                                   jeb->offset, c->sector_size, ofs, sizeof(*node)));
 622                         if ((err = jffs2_scan_dirty_space(c, jeb, (jeb->offset + c->sector_size)-ofs)))
 623                                 return err;
 624                         break;
 625                 }
 626
 627                 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
 628                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 629                         D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
 630                                   sizeof(struct jffs2_unknown_node), buf_len, ofs));
 631                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 632                         if (err)
 633                                 return err;
 634                         buf_ofs = ofs;
 635                 }
 636
 637                 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
 638
 639                 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
 640                         uint32_t inbuf_ofs;
 641                         uint32_t empty_start, scan_end;
 642
 643                         empty_start = ofs;
 644                         ofs += 4;
 645                         scan_end = min_t(uint32_t, EMPTY_SCAN_SIZE(c->sector_size)/8, buf_len);
 646
 647                         D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs));
 648                 more_empty:
 649                         inbuf_ofs = ofs - buf_ofs;
 650                         while (inbuf_ofs < scan_end) {
 651                                 if (unlikely(*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff)) {
 652                                         printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n",
 653                                                empty_start, ofs);
 654                                         if ((err = jffs2_scan_dirty_space(c, jeb, ofs-empty_start)))
 655                                                 return err;
 656                                         goto scan_more;
 657                                 }
 658
 659                                 inbuf_ofs+=4;
 660                                 ofs += 4;
 661                         }
 662                         /* Ran off end. */
 663                         D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs));
 664
 665                         /* If we're only checking the beginning of a block with a cleanmarker,
 666                            bail now */
 667                         if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&
 668                             c->cleanmarker_size && !jeb->dirty_size && !ref_next(jeb->first_node)) {
 669                                 D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE(c->sector_size)));
 670                                 return BLK_STATE_CLEANMARKER;
 671                         }
 672                         if (!buf_size && (scan_end != buf_len)) {/* XIP/point case */
 673                                 scan_end = buf_len;
 674                                 goto more_empty;
 675                         }
 676
 677                         /* See how much more there is to read in this eraseblock... */
 678                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 679                         if (!buf_len) {
 680                                 /* No more to read. Break out of main loop without marking
 681                                    this range of empty space as dirty (because it's not) */
 682                                 D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block. Treating as free_space\n",
 683                                           empty_start));
 684                                 break;
 685                         }
 686                         /* point never reaches here */
 687                         scan_end = buf_len;
 688                         D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs));
 689                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 690                         if (err)
 691                                 return err;
 692                         buf_ofs = ofs;
 693                         goto more_empty;
 694                 }
 695
 696                 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
 697                         printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n", ofs);
 698                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 699                                 return err;
 700                         ofs += 4;
 701                         continue;
 702                 }
 703                 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
 704                         D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs));
 705                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 706                                 return err;
 707                         ofs += 4;
 708                         continue;
 709                 }
 710                 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
 711                         printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08x\n", ofs);
 712                         printk(KERN_WARNING "You cannot use older JFFS2 filesystems with newer kernels\n");
 713                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 714                                 return err;
 715                         ofs += 4;
 716                         continue;
 717                 }
 718                 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
 719                         /* OK. We're out of possibilities. Whinge and move on */
 720                         noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n",
 721                                      JFFS2_MAGIC_BITMASK, ofs,
 722                                      je16_to_cpu(node->magic));
 723                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 724                                 return err;
 725                         ofs += 4;
 726                         continue;
 727                 }
 728                 /* We seem to have a node of sorts. Check the CRC */
 729                 crcnode.magic = node->magic;
 730                 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
 731                 crcnode.totlen = node->totlen;
 732                 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
 733
 734                 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
 735                         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",
 736                                      ofs, je16_to_cpu(node->magic),
 737                                      je16_to_cpu(node->nodetype),
 738                                      je32_to_cpu(node->totlen),
 739                                      je32_to_cpu(node->hdr_crc),
 740                                      hdr_crc);
 741                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 742                                 return err;
 743                         ofs += 4;
 744                         continue;
 745                 }
 746
 747                 if (ofs + je32_to_cpu(node->totlen) > jeb->offset + c->sector_size) {
 748                         /* Eep. Node goes over the end of the erase block. */
 749                         printk(KERN_WARNING "Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
 750                                ofs, je32_to_cpu(node->totlen));
 751                         printk(KERN_WARNING "Perhaps the file system was created with the wrong erase size?\n");
 752                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 753                                 return err;
 754                         ofs += 4;
 755                         continue;
 756                 }
 757
 758                 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
 759                         /* Wheee. This is an obsoleted node */
 760                         D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs));
 761                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 762                                 return err;
 763                         ofs += PAD(je32_to_cpu(node->totlen));
 764                         continue;
 765                 }
 766
 767                 switch(je16_to_cpu(node->nodetype)) {
 768                 case JFFS2_NODETYPE_INODE:
 769                         if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
 770                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 771                                 D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
 772                                           sizeof(struct jffs2_raw_inode), buf_len, ofs));
 773                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 774                                 if (err)
 775                                         return err;
 776                                 buf_ofs = ofs;
 777                                 node = (void *)buf;
 778                         }
 779                         err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs, s);
 780                         if (err) return err;
 781                         ofs += PAD(je32_to_cpu(node->totlen));
 782                         break;
 783
 784                 case JFFS2_NODETYPE_DIRENT:
 785                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 786                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 787                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
 788                                           je32_to_cpu(node->totlen), buf_len, ofs));
 789                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 790                                 if (err)
 791                                         return err;
 792                                 buf_ofs = ofs;
 793                                 node = (void *)buf;
 794                         }
 795                         err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs, s);
 796                         if (err) return err;
 797                         ofs += PAD(je32_to_cpu(node->totlen));
 798                         break;
 799
 800 #ifdef CONFIG_JFFS2_FS_XATTR
 801                 case JFFS2_NODETYPE_XATTR:
 802                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 803                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 804                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (xattr node)"
 805                                           " left to end of buf. Reading 0x%x at 0x%08x\n",
 806                                           je32_to_cpu(node->totlen), buf_len, ofs));
 807                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 808                                 if (err)
 809                                         return err;
 810                                 buf_ofs = ofs;
 811                                 node = (void *)buf;
 812                         }
 813                         err = jffs2_scan_xattr_node(c, jeb, (void *)node, ofs, s);
 814                         if (err)
 815                                 return err;
 816                         ofs += PAD(je32_to_cpu(node->totlen));
 817                         break;
 818                 case JFFS2_NODETYPE_XREF:
 819                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 820                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 821                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (xref node)"
 822                                           " left to end of buf. Reading 0x%x at 0x%08x\n",
 823                                           je32_to_cpu(node->totlen), buf_len, ofs));
 824                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 825                                 if (err)
 826                                         return err;
 827                                 buf_ofs = ofs;
 828                                 node = (void *)buf;
 829                         }
 830                         err = jffs2_scan_xref_node(c, jeb, (void *)node, ofs, s);
 831                         if (err)
 832                                 return err;
 833                         ofs += PAD(je32_to_cpu(node->totlen));
 834                         break;
 835 #endif  /* CONFIG_JFFS2_FS_XATTR */
 836
 837                 case JFFS2_NODETYPE_CLEANMARKER:
 838                         D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs));
 839                         if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
 840                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n",
 841                                        ofs, je32_to_cpu(node->totlen), c->cleanmarker_size);
 842                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
 843                                         return err;
 844                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 845                         } else if (jeb->first_node) {
 846                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n", ofs, jeb->offset);
 847                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
 848                                         return err;
 849                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 850                         } else {
 851                                 jffs2_link_node_ref(c, jeb, ofs | REF_NORMAL, c->cleanmarker_size, NULL);
 852
 853                                 ofs += PAD(c->cleanmarker_size);
 854                         }
 855                         break;
 856
 857                 case JFFS2_NODETYPE_PADDING:
 858                         if (jffs2_sum_active())
 859                                 jffs2_sum_add_padding_mem(s, je32_to_cpu(node->totlen));
 860                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 861                                 return err;
 862                         ofs += PAD(je32_to_cpu(node->totlen));
 863                         break;
 864
 865                 default:
 866                         switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
 867                         case JFFS2_FEATURE_ROCOMPAT:
 868                                 printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 869                                 c->flags |= JFFS2_SB_FLAG_RO;
 870                                 if (!(jffs2_is_readonly(c)))
 871                                         return -EROFS;
 872                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 873                                         return err;
 874                                 ofs += PAD(je32_to_cpu(node->totlen));
 875                                 break;
 876
 877                         case JFFS2_FEATURE_INCOMPAT:
 878                                 printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 879                                 return -EINVAL;
 880
 881                         case JFFS2_FEATURE_RWCOMPAT_DELETE:
 882                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 883                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 884                                         return err;
 885                                 ofs += PAD(je32_to_cpu(node->totlen));
 886                                 break;
 887
 888                         case JFFS2_FEATURE_RWCOMPAT_COPY: {
 889                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 890
 891                                 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(node->totlen)), NULL);
 892
 893                                 /* We can't summarise nodes we don't grok */
 894                                 jffs2_sum_disable_collecting(s);
 895                                 ofs += PAD(je32_to_cpu(node->totlen));
 896                                 break;
 897                                 }
 898                         }
 899                 }
 900         }
 901
 902         if (jffs2_sum_active()) {
 903                 if (PAD(s->sum_size + JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size) {
 904                         dbg_summary("There is not enough space for "
 905                                 "summary information, disabling for this jeb!\n");
 906                         jffs2_sum_disable_collecting(s);
 907                 }
 908         }
 909
 910         D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x, wasted 0x%08x\n",
 911                   jeb->offset,jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size, jeb->wasted_size));
 912
 913         /* mark_node_obsolete can add to wasted !! */
 914         if (jeb->wasted_size) {
 915                 jeb->dirty_size += jeb->wasted_size;
 916                 c->dirty_size += jeb->wasted_size;
 917                 c->wasted_size -= jeb->wasted_size;
 918                 jeb->wasted_size = 0;
 919         }
 920
 921         return jffs2_scan_classify_jeb(c, jeb);
 922 }
 923
 924 struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
 925 {
 926         struct jffs2_inode_cache *ic;
 927
 928         ic = jffs2_get_ino_cache(c, ino);
 929         if (ic)
 930                 return ic;
 931
 932         if (ino > c->highest_ino)
 933                 c->highest_ino = ino;
 934
 935         ic = jffs2_alloc_inode_cache();
 936         if (!ic) {
 937                 printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n");
 938                 return NULL;
 939         }
 940         memset(ic, 0, sizeof(*ic));
 941
 942         ic->ino = ino;
 943         ic->nodes = (void *)ic;
 944         jffs2_add_ino_cache(c, ic);
 945         if (ino == 1)
 946                 ic->pino_nlink = 1;
 947         return ic;
 948 }
 949
 950 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 951                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s)
 952 {
 953         struct jffs2_inode_cache *ic;
 954         uint32_t crc, ino = je32_to_cpu(ri->ino);
 955
 956         D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs));
 957
 958         /* We do very little here now. Just check the ino# to which we should attribute
 959            this node; we can do all the CRC checking etc. later. There's a tradeoff here --
 960            we used to scan the flash once only, reading everything we want from it into
 961            memory, then building all our in-core data structures and freeing the extra
 962            information. Now we allow the first part of the mount to complete a lot quicker,
 963            but we have to go _back_ to the flash in order to finish the CRC checking, etc.
 964            Which means that the _full_ amount of time to get to proper write mode with GC
 965            operational may actually be _longer_ than before. Sucks to be me. */
 966
 967         /* Check the node CRC in any case. */
 968         crc = crc32(0, ri, sizeof(*ri)-8);
 969         if (crc != je32_to_cpu(ri->node_crc)) {
 970                 printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on "
 971                        "node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 972                        ofs, je32_to_cpu(ri->node_crc), crc);
 973                 /*
 974                  * We believe totlen because the CRC on the node
 975                  * _header_ was OK, just the node itself failed.
 976                  */
 977                 return jffs2_scan_dirty_space(c, jeb,
 978                                               PAD(je32_to_cpu(ri->totlen)));
 979         }
 980
 981         ic = jffs2_get_ino_cache(c, ino);
 982         if (!ic) {
 983                 ic = jffs2_scan_make_ino_cache(c, ino);
 984                 if (!ic)
 985                         return -ENOMEM;
 986         }
 987
 988         /* Wheee. It worked */
 989         jffs2_link_node_ref(c, jeb, ofs | REF_UNCHECKED, PAD(je32_to_cpu(ri->totlen)), ic);
 990
 991         D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
 992                   je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
 993                   je32_to_cpu(ri->offset),
 994                   je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize)));
 995
 996         pseudo_random += je32_to_cpu(ri->version);
 997
 998         if (jffs2_sum_active()) {
 999                 jffs2_sum_add_inode_mem(s, ri, ofs - jeb->offset);
1000         }
1001
1002         return 0;
1003 }
1004
1005 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
1006                                   struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s)
1007 {
1008         struct jffs2_full_dirent *fd;
1009         struct jffs2_inode_cache *ic;
1010         uint32_t checkedlen;
1011         uint32_t crc;
1012         int err;
1013
1014         D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs));
1015
1016         /* We don't get here unless the node is still valid, so we don't have to
1017            mask in the ACCURATE bit any more. */
1018         crc = crc32(0, rd, sizeof(*rd)-8);
1019
1020         if (crc != je32_to_cpu(rd->node_crc)) {
1021                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1022                        ofs, je32_to_cpu(rd->node_crc), crc);
1023                 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
1024                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1025                         return err;
1026                 return 0;
1027         }
1028
1029         pseudo_random += je32_to_cpu(rd->version);
1030
1031         /* Should never happen. Did. (OLPC trac #4184)*/
1032         checkedlen = strnlen(rd->name, rd->nsize);
1033         if (checkedlen < rd->nsize) {
1034                 printk(KERN_ERR "Dirent at %08x has zeroes in name. Truncating to %d chars\n",
1035                        ofs, checkedlen);
1036         }
1037         fd = jffs2_alloc_full_dirent(checkedlen+1);
1038         if (!fd) {
1039                 return -ENOMEM;
1040         }
1041         memcpy(&fd->name, rd->name, checkedlen);
1042         fd->name[checkedlen] = 0;
1043
1044         crc = crc32(0, fd->name, rd->nsize);
1045         if (crc != je32_to_cpu(rd->name_crc)) {
1046                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1047                        ofs, je32_to_cpu(rd->name_crc), crc);
1048                 D1(printk(KERN_NOTICE "Name for which CRC failed is (now) '%s', ino #%d\n", fd->name, je32_to_cpu(rd->ino)));
1049                 jffs2_free_full_dirent(fd);
1050                 /* FIXME: Why do we believe totlen? */
1051                 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
1052                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1053                         return err;
1054                 return 0;
1055         }
1056         ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
1057         if (!ic) {
1058                 jffs2_free_full_dirent(fd);
1059                 return -ENOMEM;
1060         }
1061
1062         fd->raw = jffs2_link_node_ref(c, jeb, ofs | dirent_node_state(rd),
1063                                       PAD(je32_to_cpu(rd->totlen)), ic);
1064
1065         fd->next = NULL;
1066         fd->version = je32_to_cpu(rd->version);
1067         fd->ino = je32_to_cpu(rd->ino);
1068         fd->nhash = full_name_hash(fd->name, checkedlen);
1069         fd->type = rd->type;
1070         jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
1071
1072         if (jffs2_sum_active()) {
1073                 jffs2_sum_add_dirent_mem(s, rd, ofs - jeb->offset);
1074         }
1075
1076         return 0;
1077 }
1078
1079 static int count_list(struct list_head *l)
1080 {
1081         uint32_t count = 0;
1082         struct list_head *tmp;
1083
1084         list_for_each(tmp, l) {
1085                 count++;
1086         }
1087         return count;
1088 }
1089
1090 /* Note: This breaks if list_empty(head). I don't care. You
1091    might, if you copy this code and use it elsewhere :) */
1092 static void rotate_list(struct list_head *head, uint32_t count)
1093 {
1094         struct list_head *n = head->next;
1095
1096         list_del(head);
1097         while(count--) {
1098                 n = n->next;
1099         }
1100         list_add(head, n);
1101 }
1102
1103 void jffs2_rotate_lists(struct jffs2_sb_info *c)
1104 {
1105         uint32_t x;
1106         uint32_t rotateby;
1107
1108         x = count_list(&c->clean_list);
1109         if (x) {
1110                 rotateby = pseudo_random % x;
1111                 rotate_list((&c->clean_list), rotateby);
1112         }
1113
1114         x = count_list(&c->very_dirty_list);
1115         if (x) {
1116                 rotateby = pseudo_random % x;
1117                 rotate_list((&c->very_dirty_list), rotateby);
1118         }
1119
1120         x = count_list(&c->dirty_list);
1121         if (x) {
1122                 rotateby = pseudo_random % x;
1123                 rotate_list((&c->dirty_list), rotateby);
1124         }
1125
1126         x = count_list(&c->erasable_list);
1127         if (x) {
1128                 rotateby = pseudo_random % x;
1129                 rotate_list((&c->erasable_list), rotateby);
1130         }
1131
1132         if (c->nr_erasing_blocks) {
1133                 rotateby = pseudo_random % c->nr_erasing_blocks;
1134                 rotate_list((&c->erase_pending_list), rotateby);
1135         }
1136
1137         if (c->nr_free_blocks) {
1138                 rotateby = pseudo_random % c->nr_free_blocks;
1139                 rotate_list((&c->free_list), rotateby);
1140         }
1141 }