fs/jffs2/scan.c

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