fs/jffs2/scan.c

   1 /*
   2  * JFFS2 -- Journalling Flash File System, Version 2.
   3  *
   4  * Copyright © 2001-2007 Red Hat, Inc.
   5  *
   6  * Created by David Woodhouse <dwmw2@infradead.org>
   7  *
   8  * For licensing information, see the file 'LICENCE' in this directory.
   9  *
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/kernel.h>
  15 #include <linux/sched.h>
  16 #include <linux/slab.h>
  17 #include <linux/mtd/mtd.h>
  18 #include <linux/pagemap.h>
  19 #include <linux/crc32.h>
  20 #include <linux/compiler.h>
  21 #include "nodelist.h"
  22 #include "summary.h"
  23 #include "debug.h"
  24
  25 #define DEFAULT_EMPTY_SCAN_SIZE 256
  26
  27 #define noisy_printk(noise, fmt, ...)                                   \
  28 do {                                                                    \
  29         if (*(noise)) {                                                 \
  30                 pr_notice(fmt, ##__VA_ARGS__);                          \
  31                 (*(noise))--;                                           \
  32                 if (!(*(noise)))                                        \
  33                         pr_notice("Further such events for this erase block will not be printed\n"); \
  34         }                                                               \
  35 } while (0)
  36
  37 static uint32_t pseudo_random;
  38
  39 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  40                                   unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s);
  41
  42 /* These helper functions _must_ increase ofs and also do the dirty/used space accounting.
  43  * Returning an error will abort the mount - bad checksums etc. should just mark the space
  44  * as dirty.
  45  */
  46 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  47                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s);
  48 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  49                                  struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s);
  50
  51 static inline int min_free(struct jffs2_sb_info *c)
  52 {
  53         uint32_t min = 2 * sizeof(struct jffs2_raw_inode);
  54 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
  55         if (!jffs2_can_mark_obsolete(c) && min < c->wbuf_pagesize)
  56                 return c->wbuf_pagesize;
  57 #endif
  58         return min;
  59
  60 }
  61
  62 static inline uint32_t EMPTY_SCAN_SIZE(uint32_t sector_size) {
  63         if (sector_size < DEFAULT_EMPTY_SCAN_SIZE)
  64                 return sector_size;
  65         else
  66                 return DEFAULT_EMPTY_SCAN_SIZE;
  67 }
  68
  69 static int file_dirty(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
  70 {
  71         int ret;
  72
  73         if ((ret = jffs2_prealloc_raw_node_refs(c, jeb, 1)))
  74                 return ret;
  75         if ((ret = jffs2_scan_dirty_space(c, jeb, jeb->free_size)))
  76                 return ret;
  77         /* Turned wasted size into dirty, since we apparently
  78            think it's recoverable now. */
  79         jeb->dirty_size += jeb->wasted_size;
  80         c->dirty_size += jeb->wasted_size;
  81         c->wasted_size -= jeb->wasted_size;
  82         jeb->wasted_size = 0;
  83         if (VERYDIRTY(c, jeb->dirty_size)) {
  84                 list_add(&jeb->list, &c->very_dirty_list);
  85         } else {
  86                 list_add(&jeb->list, &c->dirty_list);
  87         }
  88         return 0;
  89 }
  90
  91 int jffs2_scan_medium(struct jffs2_sb_info *c)
  92 {
  93         int i, ret;
  94         uint32_t empty_blocks = 0, bad_blocks = 0;
  95         unsigned char *flashbuf = NULL;
  96         uint32_t buf_size = 0;
  97         struct jffs2_summary *s = NULL; /* summary info collected by the scan process */
  98 #ifndef __ECOS
  99         size_t pointlen, try_size;
 100
 101         ret = mtd_point(c->mtd, 0, c->mtd->size, &pointlen,
 102                         (void **)&flashbuf, NULL);
 103         if (!ret && pointlen < c->mtd->size) {
 104                 /* Don't muck about if it won't let us point to the whole flash */
 105                 jffs2_dbg(1, "MTD point returned len too short: 0x%zx\n",
 106                           pointlen);
 107                 mtd_unpoint(c->mtd, 0, pointlen);
 108                 flashbuf = NULL;
 109         }
 110         if (ret && ret != -EOPNOTSUPP)
 111                 jffs2_dbg(1, "MTD point failed %d\n", ret);
 112 #endif
 113         if (!flashbuf) {
 114                 /* For NAND it's quicker to read a whole eraseblock at a time,
 115                    apparently */
 116                 if (jffs2_cleanmarker_oob(c))
 117                         try_size = c->sector_size;
 118                 else
 119                         try_size = PAGE_SIZE;
 120
 121                 jffs2_dbg(1, "Trying to allocate readbuf of %zu "
 122                           "bytes\n", try_size);
 123
 124                 flashbuf = mtd_kmalloc_up_to(c->mtd, &try_size);
 125                 if (!flashbuf)
 126                         return -ENOMEM;
 127
 128                 jffs2_dbg(1, "Allocated readbuf of %zu bytes\n",
 129                           try_size);
 130
 131                 buf_size = (uint32_t)try_size;
 132         }
 133
 134         if (jffs2_sum_active()) {
 135                 s = kzalloc(sizeof(struct jffs2_summary), GFP_KERNEL);
 136                 if (!s) {
 137                         JFFS2_WARNING("Can't allocate memory for summary\n");
 138                         ret = -ENOMEM;
 139                         goto out_buf;
 140                 }
 141         }
 142
 143         for (i=0; i<c->nr_blocks; i++) {
 144                 struct jffs2_eraseblock *jeb = &c->blocks[i];
 145
 146                 cond_resched();
 147
 148                 /* reset summary info for next eraseblock scan */
 149                 jffs2_sum_reset_collected(s);
 150
 151                 ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset),
 152                                                 buf_size, s);
 153
 154                 if (ret < 0)
 155                         goto out;
 156
 157                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 158
 159                 /* Now decide which list to put it on */
 160                 switch(ret) {
 161                 case BLK_STATE_ALLFF:
 162                         /*
 163                          * Empty block.   Since we can't be sure it
 164                          * was entirely erased, we just queue it for erase
 165                          * again.  It will be marked as such when the erase
 166                          * is complete.  Meanwhile we still count it as empty
 167                          * for later checks.
 168                          */
 169                         empty_blocks++;
 170                         list_add(&jeb->list, &c->erase_pending_list);
 171                         c->nr_erasing_blocks++;
 172                         break;
 173
 174                 case BLK_STATE_CLEANMARKER:
 175                         /* Only a CLEANMARKER node is valid */
 176                         if (!jeb->dirty_size) {
 177                                 /* It's actually free */
 178                                 list_add(&jeb->list, &c->free_list);
 179                                 c->nr_free_blocks++;
 180                         } else {
 181                                 /* Dirt */
 182                                 jffs2_dbg(1, "Adding all-dirty block at 0x%08x to erase_pending_list\n",
 183                                           jeb->offset);
 184                                 list_add(&jeb->list, &c->erase_pending_list);
 185                                 c->nr_erasing_blocks++;
 186                         }
 187                         break;
 188
 189                 case BLK_STATE_CLEAN:
 190                         /* Full (or almost full) of clean data. Clean list */
 191                         list_add(&jeb->list, &c->clean_list);
 192                         break;
 193
 194                 case BLK_STATE_PARTDIRTY:
 195                         /* Some data, but not full. Dirty list. */
 196                         /* We want to remember the block with most free space
 197                         and stick it in the 'nextblock' position to start writing to it. */
 198                         if (jeb->free_size > min_free(c) &&
 199                                         (!c->nextblock || c->nextblock->free_size < jeb->free_size)) {
 200                                 /* Better candidate for the next writes to go to */
 201                                 if (c->nextblock) {
 202                                         ret = file_dirty(c, c->nextblock);
 203                                         if (ret)
 204                                                 goto out;
 205                                         /* deleting summary information of the old nextblock */
 206                                         jffs2_sum_reset_collected(c->summary);
 207                                 }
 208                                 /* update collected summary information for the current nextblock */
 209                                 jffs2_sum_move_collected(c, s);
 210                                 jffs2_dbg(1, "%s(): new nextblock = 0x%08x\n",
 211                                           __func__, jeb->offset);
 212                                 c->nextblock = jeb;
 213                         } else {
 214                                 ret = file_dirty(c, jeb);
 215                                 if (ret)
 216                                         goto out;
 217                         }
 218                         break;
 219
 220                 case BLK_STATE_ALLDIRTY:
 221                         /* Nothing valid - not even a clean marker. Needs erasing. */
 222                         /* For now we just put it on the erasing list. We'll start the erases later */
 223                         jffs2_dbg(1, "Erase block at 0x%08x is not formatted. It will be erased\n",
 224                                   jeb->offset);
 225                         list_add(&jeb->list, &c->erase_pending_list);
 226                         c->nr_erasing_blocks++;
 227                         break;
 228
 229                 case BLK_STATE_BADBLOCK:
 230                         jffs2_dbg(1, "Block at 0x%08x is bad\n", jeb->offset);
 231                         list_add(&jeb->list, &c->bad_list);
 232                         c->bad_size += c->sector_size;
 233                         c->free_size -= c->sector_size;
 234                         bad_blocks++;
 235                         break;
 236                 default:
 237                         pr_warn("%s(): unknown block state\n", __func__);
 238                         BUG();
 239                 }
 240         }
 241
 242         /* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
 243         if (c->nextblock && (c->nextblock->dirty_size)) {
 244                 c->nextblock->wasted_size += c->nextblock->dirty_size;
 245                 c->wasted_size += c->nextblock->dirty_size;
 246                 c->dirty_size -= c->nextblock->dirty_size;
 247                 c->nextblock->dirty_size = 0;
 248         }
 249 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 250         if (!jffs2_can_mark_obsolete(c) && c->wbuf_pagesize && c->nextblock && (c->nextblock->free_size % c->wbuf_pagesize)) {
 251                 /* If we're going to start writing into a block which already
 252                    contains data, and the end of the data isn't page-aligned,
 253                    skip a little and align it. */
 254
 255                 uint32_t skip = c->nextblock->free_size % c->wbuf_pagesize;
 256
 257                 jffs2_dbg(1, "%s(): Skipping %d bytes in nextblock to ensure page alignment\n",
 258                           __func__, skip);
 259                 jffs2_prealloc_raw_node_refs(c, c->nextblock, 1);
 260                 jffs2_scan_dirty_space(c, c->nextblock, skip);
 261         }
 262 #endif
 263         if (c->nr_erasing_blocks) {
 264                 if ( !c->used_size && ((c->nr_free_blocks+empty_blocks+bad_blocks)!= c->nr_blocks || bad_blocks == c->nr_blocks) ) {
 265                         pr_notice("Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
 266                         pr_notice("empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",
 267                                   empty_blocks, bad_blocks, c->nr_blocks);
 268                         ret = -EIO;
 269                         goto out;
 270                 }
 271                 spin_lock(&c->erase_completion_lock);
 272                 jffs2_garbage_collect_trigger(c);
 273                 spin_unlock(&c->erase_completion_lock);
 274         }
 275         ret = 0;
 276  out:
 277         jffs2_sum_reset_collected(s);
 278         kfree(s);
 279  out_buf:
 280         if (buf_size)
 281                 kfree(flashbuf);
 282 #ifndef __ECOS
 283         else
 284                 mtd_unpoint(c->mtd, 0, c->mtd->size);
 285 #endif
 286         return ret;
 287 }
 288
 289 static int jffs2_fill_scan_buf(struct jffs2_sb_info *c, void *buf,
 290                                uint32_t ofs, uint32_t len)
 291 {
 292         int ret;
 293         size_t retlen;
 294
 295         ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
 296         if (ret) {
 297                 jffs2_dbg(1, "mtd->read(0x%x bytes from 0x%x) returned %d\n",
 298                           len, ofs, ret);
 299                 return ret;
 300         }
 301         if (retlen < len) {
 302                 jffs2_dbg(1, "Read at 0x%x gave only 0x%zx bytes\n",
 303                           ofs, retlen);
 304                 return -EIO;
 305         }
 306         return 0;
 307 }
 308
 309 int jffs2_scan_classify_jeb(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
 310 {
 311         if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size
 312             && (!jeb->first_node || !ref_next(jeb->first_node)) )
 313                 return BLK_STATE_CLEANMARKER;
 314
 315         /* move blocks with max 4 byte dirty space to cleanlist */
 316         else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
 317                 c->dirty_size -= jeb->dirty_size;
 318                 c->wasted_size += jeb->dirty_size;
 319                 jeb->wasted_size += jeb->dirty_size;
 320                 jeb->dirty_size = 0;
 321                 return BLK_STATE_CLEAN;
 322         } else if (jeb->used_size || jeb->unchecked_size)
 323                 return BLK_STATE_PARTDIRTY;
 324         else
 325                 return BLK_STATE_ALLDIRTY;
 326 }
 327
 328 #ifdef CONFIG_JFFS2_FS_XATTR
 329 static int jffs2_scan_xattr_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 330                                  struct jffs2_raw_xattr *rx, uint32_t ofs,
 331                                  struct jffs2_summary *s)
 332 {
 333         struct jffs2_xattr_datum *xd;
 334         uint32_t xid, version, totlen, crc;
 335         int err;
 336
 337         crc = crc32(0, rx, sizeof(struct jffs2_raw_xattr) - 4);
 338         if (crc != je32_to_cpu(rx->node_crc)) {
 339                 JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
 340                               ofs, je32_to_cpu(rx->node_crc), crc);
 341                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
 342                         return err;
 343                 return 0;
 344         }
 345
 346         xid = je32_to_cpu(rx->xid);
 347         version = je32_to_cpu(rx->version);
 348
 349         totlen = PAD(sizeof(struct jffs2_raw_xattr)
 350                         + rx->name_len + 1 + je16_to_cpu(rx->value_len));
 351         if (totlen != je32_to_cpu(rx->totlen)) {
 352                 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%u\n",
 353                               ofs, je32_to_cpu(rx->totlen), totlen);
 354                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
 355                         return err;
 356                 return 0;
 357         }
 358
 359         xd = jffs2_setup_xattr_datum(c, xid, version);
 360         if (IS_ERR(xd))
 361                 return PTR_ERR(xd);
 362
 363         if (xd->version > version) {
 364                 struct jffs2_raw_node_ref *raw
 365                         = jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, NULL);
 366                 raw->next_in_ino = xd->node->next_in_ino;
 367                 xd->node->next_in_ino = raw;
 368         } else {
 369                 xd->version = version;
 370                 xd->xprefix = rx->xprefix;
 371                 xd->name_len = rx->name_len;
 372                 xd->value_len = je16_to_cpu(rx->value_len);
 373                 xd->data_crc = je32_to_cpu(rx->data_crc);
 374
 375                 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, (void *)xd);
 376         }
 377
 378         if (jffs2_sum_active())
 379                 jffs2_sum_add_xattr_mem(s, rx, ofs - jeb->offset);
 380         dbg_xattr("scanning xdatum at %#08x (xid=%u, version=%u)\n",
 381                   ofs, xd->xid, xd->version);
 382         return 0;
 383 }
 384
 385 static int jffs2_scan_xref_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 386                                 struct jffs2_raw_xref *rr, uint32_t ofs,
 387                                 struct jffs2_summary *s)
 388 {
 389         struct jffs2_xattr_ref *ref;
 390         uint32_t crc;
 391         int err;
 392
 393         crc = crc32(0, rr, sizeof(*rr) - 4);
 394         if (crc != je32_to_cpu(rr->node_crc)) {
 395                 JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
 396                               ofs, je32_to_cpu(rr->node_crc), crc);
 397                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rr->totlen)))))
 398                         return err;
 399                 return 0;
 400         }
 401
 402         if (PAD(sizeof(struct jffs2_raw_xref)) != je32_to_cpu(rr->totlen)) {
 403                 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%zd\n",
 404                               ofs, je32_to_cpu(rr->totlen),
 405                               PAD(sizeof(struct jffs2_raw_xref)));
 406                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rr->totlen))))
 407                         return err;
 408                 return 0;
 409         }
 410
 411         ref = jffs2_alloc_xattr_ref();
 412         if (!ref)
 413                 return -ENOMEM;
 414
 415         /* BEFORE jffs2_build_xattr_subsystem() called,
 416          * and AFTER xattr_ref is marked as a dead xref,
 417          * ref->xid is used to store 32bit xid, xd is not used
 418          * ref->ino is used to store 32bit inode-number, ic is not used
 419          * Thoes variables are declared as union, thus using those
 420          * are exclusive. In a similar way, ref->next is temporarily
 421          * used to chain all xattr_ref object. It's re-chained to
 422          * jffs2_inode_cache in jffs2_build_xattr_subsystem() correctly.
 423          */
 424         ref->ino = je32_to_cpu(rr->ino);
 425         ref->xid = je32_to_cpu(rr->xid);
 426         ref->xseqno = je32_to_cpu(rr->xseqno);
 427         if (ref->xseqno > c->highest_xseqno)
 428                 c->highest_xseqno = (ref->xseqno & ~XREF_DELETE_MARKER);
 429         ref->next = c->xref_temp;
 430         c->xref_temp = ref;
 431
 432         jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(rr->totlen)), (void *)ref);
 433
 434         if (jffs2_sum_active())
 435                 jffs2_sum_add_xref_mem(s, rr, ofs - jeb->offset);
 436         dbg_xattr("scan xref at %#08x (xid=%u, ino=%u)\n",
 437                   ofs, ref->xid, ref->ino);
 438         return 0;
 439 }
 440 #endif
 441
 442 /* Called with 'buf_size == 0' if buf is in fact a pointer _directly_ into
 443    the flash, XIP-style */
 444 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 445                                   unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) {
 446         struct jffs2_unknown_node *node;
 447         struct jffs2_unknown_node crcnode;
 448         uint32_t ofs, prevofs, max_ofs;
 449         uint32_t hdr_crc, buf_ofs, buf_len;
 450         int err;
 451         int noise = 0;
 452
 453
 454 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 455         int cleanmarkerfound = 0;
 456 #endif
 457
 458         ofs = jeb->offset;
 459         prevofs = jeb->offset - 1;
 460
 461         jffs2_dbg(1, "%s(): Scanning block at 0x%x\n", __func__, ofs);
 462
 463 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 464         if (jffs2_cleanmarker_oob(c)) {
 465                 int ret;
 466
 467                 if (mtd_block_isbad(c->mtd, jeb->offset))
 468                         return BLK_STATE_BADBLOCK;
 469
 470                 ret = jffs2_check_nand_cleanmarker(c, jeb);
 471                 jffs2_dbg(2, "jffs_check_nand_cleanmarker returned %d\n", ret);
 472
 473                 /* Even if it's not found, we still scan to see
 474                    if the block is empty. We use this information
 475                    to decide whether to erase it or not. */
 476                 switch (ret) {
 477                 case 0:         cleanmarkerfound = 1; break;
 478                 case 1:         break;
 479                 default:        return ret;
 480                 }
 481         }
 482 #endif
 483
 484         if (jffs2_sum_active()) {
 485                 struct jffs2_sum_marker *sm;
 486                 void *sumptr = NULL;
 487                 uint32_t sumlen;
 488
 489                 if (!buf_size) {
 490                         /* XIP case. Just look, point at the summary if it's there */
 491                         sm = (void *)buf + c->sector_size - sizeof(*sm);
 492                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
 493                                 sumptr = buf + je32_to_cpu(sm->offset);
 494                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
 495                         }
 496                 } else {
 497                         /* If NAND flash, read a whole page of it. Else just the end */
 498                         if (c->wbuf_pagesize)
 499                                 buf_len = c->wbuf_pagesize;
 500                         else
 501                                 buf_len = sizeof(*sm);
 502
 503                         /* Read as much as we want into the _end_ of the preallocated buffer */
 504                         err = jffs2_fill_scan_buf(c, buf + buf_size - buf_len,
 505                                                   jeb->offset + c->sector_size - buf_len,
 506                                                   buf_len);
 507                         if (err)
 508                                 return err;
 509
 510                         sm = (void *)buf + buf_size - sizeof(*sm);
 511                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
 512                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
 513                                 sumptr = buf + buf_size - sumlen;
 514
 515                                 /* sm->offset maybe wrong but MAGIC maybe right */
 516                                 if (sumlen > c->sector_size)
 517                                         goto full_scan;
 518
 519                                 /* Now, make sure the summary itself is available */
 520                                 if (sumlen > buf_size) {
 521                                         /* Need to kmalloc for this. */
 522                                         sumptr = kmalloc(sumlen, GFP_KERNEL);
 523                                         if (!sumptr)
 524                                                 return -ENOMEM;
 525                                         memcpy(sumptr + sumlen - buf_len, buf + buf_size - buf_len, buf_len);
 526                                 }
 527                                 if (buf_len < sumlen) {
 528                                         /* Need to read more so that the entire summary node is present */
 529                                         err = jffs2_fill_scan_buf(c, sumptr,
 530                                                                   jeb->offset + c->sector_size - sumlen,
 531                                                                   sumlen - buf_len);
 532                                         if (err) {
 533                                                 if (sumlen > buf_size)
 534                                                         kfree(sumptr);
 535                                                 return err;
 536                                         }
 537                                 }
 538                         }
 539
 540                 }
 541
 542                 if (sumptr) {
 543                         err = jffs2_sum_scan_sumnode(c, jeb, sumptr, sumlen, &pseudo_random);
 544
 545                         if (buf_size && sumlen > buf_size)
 546                                 kfree(sumptr);
 547                         /* If it returns with a real error, bail.
 548                            If it returns positive, that's a block classification
 549                            (i.e. BLK_STATE_xxx) so return that too.
 550                            If it returns zero, fall through to full scan. */
 551                         if (err)
 552                                 return err;
 553                 }
 554         }
 555
 556 full_scan:
 557         buf_ofs = jeb->offset;
 558
 559         if (!buf_size) {
 560                 /* This is the XIP case -- we're reading _directly_ from the flash chip */
 561                 buf_len = c->sector_size;
 562         } else {
 563                 buf_len = EMPTY_SCAN_SIZE(c->sector_size);
 564                 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
 565                 if (err)
 566                         return err;
 567         }
 568
 569         /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
 570         ofs = 0;
 571         max_ofs = EMPTY_SCAN_SIZE(c->sector_size);
 572         /* Scan only EMPTY_SCAN_SIZE of 0xFF before declaring it's empty */
 573         while(ofs < max_ofs && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
 574                 ofs += 4;
 575
 576         if (ofs == max_ofs) {
 577 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 578                 if (jffs2_cleanmarker_oob(c)) {
 579                         /* scan oob, take care of cleanmarker */
 580                         int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
 581                         jffs2_dbg(2, "jffs2_check_oob_empty returned %d\n",
 582                                   ret);
 583                         switch (ret) {
 584                         case 0:         return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
 585                         case 1:         return BLK_STATE_ALLDIRTY;
 586                         default:        return ret;
 587                         }
 588                 }
 589 #endif
 590                 jffs2_dbg(1, "Block at 0x%08x is empty (erased)\n",
 591                           jeb->offset);
 592                 if (c->cleanmarker_size == 0)
 593                         return BLK_STATE_CLEANMARKER;   /* don't bother with re-erase */
 594                 else
 595                         return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
 596         }
 597         if (ofs) {
 598                 jffs2_dbg(1, "Free space at %08x ends at %08x\n", jeb->offset,
 599                           jeb->offset + ofs);
 600                 if ((err = jffs2_prealloc_raw_node_refs(c, jeb, 1)))
 601                         return err;
 602                 if ((err = jffs2_scan_dirty_space(c, jeb, ofs)))
 603                         return err;
 604         }
 605
 606         /* Now ofs is a complete physical flash offset as it always was... */
 607         ofs += jeb->offset;
 608
 609         noise = 10;
 610
 611         dbg_summary("no summary found in jeb 0x%08x. Apply original scan.\n",jeb->offset);
 612
 613 scan_more:
 614         while(ofs < jeb->offset + c->sector_size) {
 615
 616                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 617
 618                 /* Make sure there are node refs available for use */
 619                 err = jffs2_prealloc_raw_node_refs(c, jeb, 2);
 620                 if (err)
 621                         return err;
 622
 623                 cond_resched();
 624
 625                 if (ofs & 3) {
 626                         pr_warn("Eep. ofs 0x%08x not word-aligned!\n", ofs);
 627                         ofs = PAD(ofs);
 628                         continue;
 629                 }
 630                 if (ofs == prevofs) {
 631                         pr_warn("ofs 0x%08x has already been seen. Skipping\n",
 632                                 ofs);
 633                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 634                                 return err;
 635                         ofs += 4;
 636                         continue;
 637                 }
 638                 prevofs = ofs;
 639
 640                 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
 641                         jffs2_dbg(1, "Fewer than %zd bytes left to end of block. (%x+%x<%x+%zx) Not reading\n",
 642                                   sizeof(struct jffs2_unknown_node),
 643                                   jeb->offset, c->sector_size, ofs,
 644                                   sizeof(*node));
 645                         if ((err = jffs2_scan_dirty_space(c, jeb, (jeb->offset + c->sector_size)-ofs)))
 646                                 return err;
 647                         break;
 648                 }
 649
 650                 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
 651                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 652                         jffs2_dbg(1, "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
 653                                   sizeof(struct jffs2_unknown_node),
 654                                   buf_len, ofs);
 655                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 656                         if (err)
 657                                 return err;
 658                         buf_ofs = ofs;
 659                 }
 660
 661                 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
 662
 663                 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
 664                         uint32_t inbuf_ofs;
 665                         uint32_t empty_start, scan_end;
 666
 667                         empty_start = ofs;
 668                         ofs += 4;
 669                         scan_end = min_t(uint32_t, EMPTY_SCAN_SIZE(c->sector_size)/8, buf_len);
 670
 671                         jffs2_dbg(1, "Found empty flash at 0x%08x\n", ofs);
 672                 more_empty:
 673                         inbuf_ofs = ofs - buf_ofs;
 674                         while (inbuf_ofs < scan_end) {
 675                                 if (unlikely(*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff)) {
 676                                         pr_warn("Empty flash at 0x%08x ends at 0x%08x\n",
 677                                                 empty_start, ofs);
 678                                         if ((err = jffs2_scan_dirty_space(c, jeb, ofs-empty_start)))
 679                                                 return err;
 680                                         goto scan_more;
 681                                 }
 682
 683                                 inbuf_ofs+=4;
 684                                 ofs += 4;
 685                         }
 686                         /* Ran off end. */
 687                         jffs2_dbg(1, "Empty flash to end of buffer at 0x%08x\n",
 688                                   ofs);
 689
 690                         /* If we're only checking the beginning of a block with a cleanmarker,
 691                            bail now */
 692                         if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&
 693                             c->cleanmarker_size && !jeb->dirty_size && !ref_next(jeb->first_node)) {
 694                                 jffs2_dbg(1, "%d bytes at start of block seems clean... assuming all clean\n",
 695                                           EMPTY_SCAN_SIZE(c->sector_size));
 696                                 return BLK_STATE_CLEANMARKER;
 697                         }
 698                         if (!buf_size && (scan_end != buf_len)) {/* XIP/point case */
 699                                 scan_end = buf_len;
 700                                 goto more_empty;
 701                         }
 702
 703                         /* See how much more there is to read in this eraseblock... */
 704                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 705                         if (!buf_len) {
 706                                 /* No more to read. Break out of main loop without marking
 707                                    this range of empty space as dirty (because it's not) */
 708                                 jffs2_dbg(1, "Empty flash at %08x runs to end of block. Treating as free_space\n",
 709                                           empty_start);
 710                                 break;
 711                         }
 712                         /* point never reaches here */
 713                         scan_end = buf_len;
 714                         jffs2_dbg(1, "Reading another 0x%x at 0x%08x\n",
 715                                   buf_len, ofs);
 716                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 717                         if (err)
 718                                 return err;
 719                         buf_ofs = ofs;
 720                         goto more_empty;
 721                 }
 722
 723                 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
 724                         pr_warn("Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n",
 725                                 ofs);
 726                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 727                                 return err;
 728                         ofs += 4;
 729                         continue;
 730                 }
 731                 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
 732                         jffs2_dbg(1, "Dirty bitmask at 0x%08x\n", ofs);
 733                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 734                                 return err;
 735                         ofs += 4;
 736                         continue;
 737                 }
 738                 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
 739                         pr_warn("Old JFFS2 bitmask found at 0x%08x\n", ofs);
 740                         pr_warn("You cannot use older JFFS2 filesystems with newer kernels\n");
 741                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 742                                 return err;
 743                         ofs += 4;
 744                         continue;
 745                 }
 746                 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
 747                         /* OK. We're out of possibilities. Whinge and move on */
 748                         noisy_printk(&noise, "%s(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n",
 749                                      __func__,
 750                                      JFFS2_MAGIC_BITMASK, ofs,
 751                                      je16_to_cpu(node->magic));
 752                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 753                                 return err;
 754                         ofs += 4;
 755                         continue;
 756                 }
 757                 /* We seem to have a node of sorts. Check the CRC */
 758                 crcnode.magic = node->magic;
 759                 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
 760                 crcnode.totlen = node->totlen;
 761                 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
 762
 763                 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
 764                         noisy_printk(&noise, "%s(): Node at 0x%08x {0x%04x, 0x%04x, 0x%08x) has invalid CRC 0x%08x (calculated 0x%08x)\n",
 765                                      __func__,
 766                                      ofs, je16_to_cpu(node->magic),
 767                                      je16_to_cpu(node->nodetype),
 768                                      je32_to_cpu(node->totlen),
 769                                      je32_to_cpu(node->hdr_crc),
 770                                      hdr_crc);
 771                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 772                                 return err;
 773                         ofs += 4;
 774                         continue;
 775                 }
 776
 777                 if (ofs + je32_to_cpu(node->totlen) > jeb->offset + c->sector_size) {
 778                         /* Eep. Node goes over the end of the erase block. */
 779                         pr_warn("Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
 780                                 ofs, je32_to_cpu(node->totlen));
 781                         pr_warn("Perhaps the file system was created with the wrong erase size?\n");
 782                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 783                                 return err;
 784                         ofs += 4;
 785                         continue;
 786                 }
 787
 788                 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
 789                         /* Wheee. This is an obsoleted node */
 790                         jffs2_dbg(2, "Node at 0x%08x is obsolete. Skipping\n",
 791                                   ofs);
 792                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 793                                 return err;
 794                         ofs += PAD(je32_to_cpu(node->totlen));
 795                         continue;
 796                 }
 797
 798                 switch(je16_to_cpu(node->nodetype)) {
 799                 case JFFS2_NODETYPE_INODE:
 800                         if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
 801                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 802                                 jffs2_dbg(1, "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
 803                                           sizeof(struct jffs2_raw_inode),
 804                                           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_inode_node(c, jeb, (void *)node, ofs, s);
 812                         if (err) return err;
 813                         ofs += PAD(je32_to_cpu(node->totlen));
 814                         break;
 815
 816                 case JFFS2_NODETYPE_DIRENT:
 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                                 jffs2_dbg(1, "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
 820                                           je32_to_cpu(node->totlen), buf_len,
 821                                           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_dirent_node(c, jeb, (void *)node, ofs, s);
 829                         if (err) return err;
 830                         ofs += PAD(je32_to_cpu(node->totlen));
 831                         break;
 832
 833 #ifdef CONFIG_JFFS2_FS_XATTR
 834                 case JFFS2_NODETYPE_XATTR:
 835                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 836                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 837                                 jffs2_dbg(1, "Fewer than %d bytes (xattr node) left to end of buf. Reading 0x%x at 0x%08x\n",
 838                                           je32_to_cpu(node->totlen), buf_len,
 839                                           ofs);
 840                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 841                                 if (err)
 842                                         return err;
 843                                 buf_ofs = ofs;
 844                                 node = (void *)buf;
 845                         }
 846                         err = jffs2_scan_xattr_node(c, jeb, (void *)node, ofs, s);
 847                         if (err)
 848                                 return err;
 849                         ofs += PAD(je32_to_cpu(node->totlen));
 850                         break;
 851                 case JFFS2_NODETYPE_XREF:
 852                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 853                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 854                                 jffs2_dbg(1, "Fewer than %d bytes (xref node) left to end of buf. Reading 0x%x at 0x%08x\n",
 855                                           je32_to_cpu(node->totlen), buf_len,
 856                                           ofs);
 857                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 858                                 if (err)
 859                                         return err;
 860                                 buf_ofs = ofs;
 861                                 node = (void *)buf;
 862                         }
 863                         err = jffs2_scan_xref_node(c, jeb, (void *)node, ofs, s);
 864                         if (err)
 865                                 return err;
 866                         ofs += PAD(je32_to_cpu(node->totlen));
 867                         break;
 868 #endif  /* CONFIG_JFFS2_FS_XATTR */
 869
 870                 case JFFS2_NODETYPE_CLEANMARKER:
 871                         jffs2_dbg(1, "CLEANMARKER node found at 0x%08x\n", ofs);
 872                         if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
 873                                 pr_notice("CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n",
 874                                           ofs, je32_to_cpu(node->totlen),
 875                                           c->cleanmarker_size);
 876                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
 877                                         return err;
 878                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 879                         } else if (jeb->first_node) {
 880                                 pr_notice("CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n",
 881                                           ofs, jeb->offset);
 882                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
 883                                         return err;
 884                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 885                         } else {
 886                                 jffs2_link_node_ref(c, jeb, ofs | REF_NORMAL, c->cleanmarker_size, NULL);
 887
 888                                 ofs += PAD(c->cleanmarker_size);
 889                         }
 890                         break;
 891
 892                 case JFFS2_NODETYPE_PADDING:
 893                         if (jffs2_sum_active())
 894                                 jffs2_sum_add_padding_mem(s, je32_to_cpu(node->totlen));
 895                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 896                                 return err;
 897                         ofs += PAD(je32_to_cpu(node->totlen));
 898                         break;
 899
 900                 default:
 901                         switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
 902                         case JFFS2_FEATURE_ROCOMPAT:
 903                                 pr_notice("Read-only compatible feature node (0x%04x) found at offset 0x%08x\n",
 904                                           je16_to_cpu(node->nodetype), ofs);
 905                                 c->flags |= JFFS2_SB_FLAG_RO;
 906                                 if (!(jffs2_is_readonly(c)))
 907                                         return -EROFS;
 908                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 909                                         return err;
 910                                 ofs += PAD(je32_to_cpu(node->totlen));
 911                                 break;
 912
 913                         case JFFS2_FEATURE_INCOMPAT:
 914                                 pr_notice("Incompatible feature node (0x%04x) found at offset 0x%08x\n",
 915                                           je16_to_cpu(node->nodetype), ofs);
 916                                 return -EINVAL;
 917
 918                         case JFFS2_FEATURE_RWCOMPAT_DELETE:
 919                                 jffs2_dbg(1, "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n",
 920                                           je16_to_cpu(node->nodetype), ofs);
 921                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 922                                         return err;
 923                                 ofs += PAD(je32_to_cpu(node->totlen));
 924                                 break;
 925
 926                         case JFFS2_FEATURE_RWCOMPAT_COPY: {
 927                                 jffs2_dbg(1, "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n",
 928                                           je16_to_cpu(node->nodetype), ofs);
 929
 930                                 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(node->totlen)), NULL);
 931
 932                                 /* We can't summarise nodes we don't grok */
 933                                 jffs2_sum_disable_collecting(s);
 934                                 ofs += PAD(je32_to_cpu(node->totlen));
 935                                 break;
 936                                 }
 937                         }
 938                 }
 939         }
 940
 941         if (jffs2_sum_active()) {
 942                 if (PAD(s->sum_size + JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size) {
 943                         dbg_summary("There is not enough space for "
 944                                 "summary information, disabling for this jeb!\n");
 945                         jffs2_sum_disable_collecting(s);
 946                 }
 947         }
 948
 949         jffs2_dbg(1, "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x, wasted 0x%08x\n",
 950                   jeb->offset, jeb->free_size, jeb->dirty_size,
 951                   jeb->unchecked_size, jeb->used_size, jeb->wasted_size);
 952
 953         /* mark_node_obsolete can add to wasted !! */
 954         if (jeb->wasted_size) {
 955                 jeb->dirty_size += jeb->wasted_size;
 956                 c->dirty_size += jeb->wasted_size;
 957                 c->wasted_size -= jeb->wasted_size;
 958                 jeb->wasted_size = 0;
 959         }
 960
 961         return jffs2_scan_classify_jeb(c, jeb);
 962 }
 963
 964 struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
 965 {
 966         struct jffs2_inode_cache *ic;
 967
 968         ic = jffs2_get_ino_cache(c, ino);
 969         if (ic)
 970                 return ic;
 971
 972         if (ino > c->highest_ino)
 973                 c->highest_ino = ino;
 974
 975         ic = jffs2_alloc_inode_cache();
 976         if (!ic) {
 977                 pr_notice("%s(): allocation of inode cache failed\n", __func__);
 978                 return NULL;
 979         }
 980         memset(ic, 0, sizeof(*ic));
 981
 982         ic->ino = ino;
 983         ic->nodes = (void *)ic;
 984         jffs2_add_ino_cache(c, ic);
 985         if (ino == 1)
 986                 ic->pino_nlink = 1;
 987         return ic;
 988 }
 989
 990 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 991                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s)
 992 {
 993         struct jffs2_inode_cache *ic;
 994         uint32_t crc, ino = je32_to_cpu(ri->ino);
 995
 996         jffs2_dbg(1, "%s(): Node at 0x%08x\n", __func__, ofs);
 997
 998         /* We do very little here now. Just check the ino# to which we should attribute
 999            this node; we can do all the CRC checking etc. later. There's a tradeoff here --
1000            we used to scan the flash once only, reading everything we want from it into
1001            memory, then building all our in-core data structures and freeing the extra
1002            information. Now we allow the first part of the mount to complete a lot quicker,
1003            but we have to go _back_ to the flash in order to finish the CRC checking, etc.
1004            Which means that the _full_ amount of time to get to proper write mode with GC
1005            operational may actually be _longer_ than before. Sucks to be me. */
1006
1007         /* Check the node CRC in any case. */
1008         crc = crc32(0, ri, sizeof(*ri)-8);
1009         if (crc != je32_to_cpu(ri->node_crc)) {
1010                 pr_notice("%s(): CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1011                           __func__, ofs, je32_to_cpu(ri->node_crc), crc);
1012                 /*
1013                  * We believe totlen because the CRC on the node
1014                  * _header_ was OK, just the node itself failed.
1015                  */
1016                 return jffs2_scan_dirty_space(c, jeb,
1017                                               PAD(je32_to_cpu(ri->totlen)));
1018         }
1019
1020         ic = jffs2_get_ino_cache(c, ino);
1021         if (!ic) {
1022                 ic = jffs2_scan_make_ino_cache(c, ino);
1023                 if (!ic)
1024                         return -ENOMEM;
1025         }
1026
1027         /* Wheee. It worked */
1028         jffs2_link_node_ref(c, jeb, ofs | REF_UNCHECKED, PAD(je32_to_cpu(ri->totlen)), ic);
1029
1030         jffs2_dbg(1, "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
1031                   je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
1032                   je32_to_cpu(ri->offset),
1033                   je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize));
1034
1035         pseudo_random += je32_to_cpu(ri->version);
1036
1037         if (jffs2_sum_active()) {
1038                 jffs2_sum_add_inode_mem(s, ri, ofs - jeb->offset);
1039         }
1040
1041         return 0;
1042 }
1043
1044 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
1045                                   struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s)
1046 {
1047         struct jffs2_full_dirent *fd;
1048         struct jffs2_inode_cache *ic;
1049         uint32_t checkedlen;
1050         uint32_t crc;
1051         int err;
1052
1053         jffs2_dbg(1, "%s(): Node at 0x%08x\n", __func__, ofs);
1054
1055         /* We don't get here unless the node is still valid, so we don't have to
1056            mask in the ACCURATE bit any more. */
1057         crc = crc32(0, rd, sizeof(*rd)-8);
1058
1059         if (crc != je32_to_cpu(rd->node_crc)) {
1060                 pr_notice("%s(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1061                           __func__, ofs, je32_to_cpu(rd->node_crc), crc);
1062                 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
1063                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1064                         return err;
1065                 return 0;
1066         }
1067
1068         pseudo_random += je32_to_cpu(rd->version);
1069
1070         /* Should never happen. Did. (OLPC trac #4184)*/
1071         checkedlen = strnlen(rd->name, rd->nsize);
1072         if (checkedlen < rd->nsize) {
1073                 pr_err("Dirent at %08x has zeroes in name. Truncating to %d chars\n",
1074                        ofs, checkedlen);
1075         }
1076         fd = jffs2_alloc_full_dirent(checkedlen+1);
1077         if (!fd) {
1078                 return -ENOMEM;
1079         }
1080         memcpy(&fd->name, rd->name, checkedlen);
1081         fd->name[checkedlen] = 0;
1082
1083         crc = crc32(0, fd->name, checkedlen);
1084         if (crc != je32_to_cpu(rd->name_crc)) {
1085                 pr_notice("%s(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1086                           __func__, ofs, je32_to_cpu(rd->name_crc), crc);
1087                 jffs2_dbg(1, "Name for which CRC failed is (now) '%s', ino #%d\n",
1088                           fd->name, je32_to_cpu(rd->ino));
1089                 jffs2_free_full_dirent(fd);
1090                 /* FIXME: Why do we believe totlen? */
1091                 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
1092                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1093                         return err;
1094                 return 0;
1095         }
1096         ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
1097         if (!ic) {
1098                 jffs2_free_full_dirent(fd);
1099                 return -ENOMEM;
1100         }
1101
1102         fd->raw = jffs2_link_node_ref(c, jeb, ofs | dirent_node_state(rd),
1103                                       PAD(je32_to_cpu(rd->totlen)), ic);
1104
1105         fd->next = NULL;
1106         fd->version = je32_to_cpu(rd->version);
1107         fd->ino = je32_to_cpu(rd->ino);
1108         fd->nhash = full_name_hash(NULL, fd->name, checkedlen);
1109         fd->type = rd->type;
1110         jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
1111
1112         if (jffs2_sum_active()) {
1113                 jffs2_sum_add_dirent_mem(s, rd, ofs - jeb->offset);
1114         }
1115
1116         return 0;
1117 }
1118
1119 static int count_list(struct list_head *l)
1120 {
1121         uint32_t count = 0;
1122         struct list_head *tmp;
1123
1124         list_for_each(tmp, l) {
1125                 count++;
1126         }
1127         return count;
1128 }
1129
1130 /* Note: This breaks if list_empty(head). I don't care. You
1131    might, if you copy this code and use it elsewhere :) */
1132 static void rotate_list(struct list_head *head, uint32_t count)
1133 {
1134         struct list_head *n = head->next;
1135
1136         list_del(head);
1137         while(count--) {
1138                 n = n->next;
1139         }
1140         list_add(head, n);
1141 }
1142
1143 void jffs2_rotate_lists(struct jffs2_sb_info *c)
1144 {
1145         uint32_t x;
1146         uint32_t rotateby;
1147
1148         x = count_list(&c->clean_list);
1149         if (x) {
1150                 rotateby = pseudo_random % x;
1151                 rotate_list((&c->clean_list), rotateby);
1152         }
1153
1154         x = count_list(&c->very_dirty_list);
1155         if (x) {
1156                 rotateby = pseudo_random % x;
1157                 rotate_list((&c->very_dirty_list), rotateby);
1158         }
1159
1160         x = count_list(&c->dirty_list);
1161         if (x) {
1162                 rotateby = pseudo_random % x;
1163                 rotate_list((&c->dirty_list), rotateby);
1164         }
1165
1166         x = count_list(&c->erasable_list);
1167         if (x) {
1168                 rotateby = pseudo_random % x;
1169                 rotate_list((&c->erasable_list), rotateby);
1170         }
1171
1172         if (c->nr_erasing_blocks) {
1173                 rotateby = pseudo_random % c->nr_erasing_blocks;
1174                 rotate_list((&c->erase_pending_list), rotateby);
1175         }
1176
1177         if (c->nr_free_blocks) {
1178                 rotateby = pseudo_random % c->nr_free_blocks;
1179                 rotate_list((&c->free_list), rotateby);
1180         }
1181 }