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   1 /*
   2  * JFFS2 -- Journalling Flash File System, Version 2.
   3  *
   4  * Copyright (C) 2001-2003 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  * $Id: scan.c,v 1.125 2005/09/30 13:59:13 dedekind Exp $
  11  *
  12  */
  13 #include <linux/kernel.h>
  14 #include <linux/sched.h>
  15 #include <linux/slab.h>
  16 #include <linux/mtd/mtd.h>
  17 #include <linux/pagemap.h>
  18 #include <linux/crc32.h>
  19 #include <linux/compiler.h>
  20 #include "nodelist.h"
  21 #include "summary.h"
  22 #include "debug.h"
  23
  24 #define DEFAULT_EMPTY_SCAN_SIZE 1024
  25
  26 #define noisy_printk(noise, args...) do { \
  27         if (*(noise)) { \
  28                 printk(KERN_NOTICE args); \
  29                  (*(noise))--; \
  30                  if (!(*(noise))) { \
  31                          printk(KERN_NOTICE "Further such events for this erase block will not be printed\n"); \
  32                  } \
  33         } \
  34 } while(0)
  35
  36 static uint32_t pseudo_random;
  37
  38 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  39                                   unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s);
  40
  41 /* These helper functions _must_ increase ofs and also do the dirty/used space accounting.
  42  * Returning an error will abort the mount - bad checksums etc. should just mark the space
  43  * as dirty.
  44  */
  45 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  46                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s);
  47 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  48                                  struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s);
  49
  50 static inline int min_free(struct jffs2_sb_info *c)
  51 {
  52         uint32_t min = 2 * sizeof(struct jffs2_raw_inode);
  53 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
  54         if (!jffs2_can_mark_obsolete(c) && min < c->wbuf_pagesize)
  55                 return c->wbuf_pagesize;
  56 #endif
  57         return min;
  58
  59 }
  60
  61 static inline uint32_t EMPTY_SCAN_SIZE(uint32_t sector_size) {
  62         if (sector_size < DEFAULT_EMPTY_SCAN_SIZE)
  63                 return sector_size;
  64         else
  65                 return DEFAULT_EMPTY_SCAN_SIZE;
  66 }
  67
  68 int jffs2_scan_medium(struct jffs2_sb_info *c)
  69 {
  70         int i, ret;
  71         uint32_t empty_blocks = 0, bad_blocks = 0;
  72         unsigned char *flashbuf = NULL;
  73         uint32_t buf_size = 0;
  74         struct jffs2_summary *s = NULL; /* summary info collected by the scan process */
  75 #ifndef __ECOS
  76         size_t pointlen;
  77
  78         if (c->mtd->point) {
  79                 ret = c->mtd->point (c->mtd, 0, c->mtd->size, &pointlen, &flashbuf);
  80                 if (!ret && pointlen < c->mtd->size) {
  81                         /* Don't muck about if it won't let us point to the whole flash */
  82                         D1(printk(KERN_DEBUG "MTD point returned len too short: 0x%zx\n", pointlen));
  83                         c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
  84                         flashbuf = NULL;
  85                 }
  86                 if (ret)
  87                         D1(printk(KERN_DEBUG "MTD point failed %d\n", ret));
  88         }
  89 #endif
  90         if (!flashbuf) {
  91                 /* For NAND it's quicker to read a whole eraseblock at a time,
  92                    apparently */
  93                 if (jffs2_cleanmarker_oob(c))
  94                         buf_size = c->sector_size;
  95                 else
  96                         buf_size = PAGE_SIZE;
  97
  98                 /* Respect kmalloc limitations */
  99                 if (buf_size > 128*1024)
 100                         buf_size = 128*1024;
 101
 102                 D1(printk(KERN_DEBUG "Allocating readbuf of %d bytes\n", buf_size));
 103                 flashbuf = kmalloc(buf_size, GFP_KERNEL);
 104                 if (!flashbuf)
 105                         return -ENOMEM;
 106         }
 107
 108         if (jffs2_sum_active()) {
 109                 s = kmalloc(sizeof(struct jffs2_summary), GFP_KERNEL);
 110                 if (!s) {
 111                         JFFS2_WARNING("Can't allocate memory for summary\n");
 112                         return -ENOMEM;
 113                 }
 114                 memset(s, 0, sizeof(struct jffs2_summary));
 115         }
 116
 117         for (i=0; i<c->nr_blocks; i++) {
 118                 struct jffs2_eraseblock *jeb = &c->blocks[i];
 119
 120                 /* reset summary info for next eraseblock scan */
 121                 jffs2_sum_reset_collected(s);
 122
 123                 ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset),
 124                                                 buf_size, s);
 125
 126                 if (ret < 0)
 127                         goto out;
 128
 129                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 130
 131                 /* Now decide which list to put it on */
 132                 switch(ret) {
 133                 case BLK_STATE_ALLFF:
 134                         /*
 135                          * Empty block.   Since we can't be sure it
 136                          * was entirely erased, we just queue it for erase
 137                          * again.  It will be marked as such when the erase
 138                          * is complete.  Meanwhile we still count it as empty
 139                          * for later checks.
 140                          */
 141                         empty_blocks++;
 142                         list_add(&jeb->list, &c->erase_pending_list);
 143                         c->nr_erasing_blocks++;
 144                         break;
 145
 146                 case BLK_STATE_CLEANMARKER:
 147                         /* Only a CLEANMARKER node is valid */
 148                         if (!jeb->dirty_size) {
 149                                 /* It's actually free */
 150                                 list_add(&jeb->list, &c->free_list);
 151                                 c->nr_free_blocks++;
 152                         } else {
 153                                 /* Dirt */
 154                                 D1(printk(KERN_DEBUG "Adding all-dirty block at 0x%08x to erase_pending_list\n", jeb->offset));
 155                                 list_add(&jeb->list, &c->erase_pending_list);
 156                                 c->nr_erasing_blocks++;
 157                         }
 158                         break;
 159
 160                 case BLK_STATE_CLEAN:
 161                         /* Full (or almost full) of clean data. Clean list */
 162                         list_add(&jeb->list, &c->clean_list);
 163                         break;
 164
 165                 case BLK_STATE_PARTDIRTY:
 166                         /* Some data, but not full. Dirty list. */
 167                         /* We want to remember the block with most free space
 168                         and stick it in the 'nextblock' position to start writing to it. */
 169                         if (jeb->free_size > min_free(c) &&
 170                                         (!c->nextblock || c->nextblock->free_size < jeb->free_size)) {
 171                                 /* Better candidate for the next writes to go to */
 172                                 if (c->nextblock) {
 173                                         c->nextblock->dirty_size += c->nextblock->free_size + c->nextblock->wasted_size;
 174                                         c->dirty_size += c->nextblock->free_size + c->nextblock->wasted_size;
 175                                         c->free_size -= c->nextblock->free_size;
 176                                         c->wasted_size -= c->nextblock->wasted_size;
 177                                         c->nextblock->free_size = c->nextblock->wasted_size = 0;
 178                                         if (VERYDIRTY(c, c->nextblock->dirty_size)) {
 179                                                 list_add(&c->nextblock->list, &c->very_dirty_list);
 180                                         } else {
 181                                                 list_add(&c->nextblock->list, &c->dirty_list);
 182                                         }
 183                                         /* deleting summary information of the old nextblock */
 184                                         jffs2_sum_reset_collected(c->summary);
 185                                 }
 186                                 /* update collected summary infromation for the current nextblock */
 187                                 jffs2_sum_move_collected(c, s);
 188                                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): new nextblock = 0x%08x\n", jeb->offset));
 189                                 c->nextblock = jeb;
 190                         } else {
 191                                 jeb->dirty_size += jeb->free_size + jeb->wasted_size;
 192                                 c->dirty_size += jeb->free_size + jeb->wasted_size;
 193                                 c->free_size -= jeb->free_size;
 194                                 c->wasted_size -= jeb->wasted_size;
 195                                 jeb->free_size = jeb->wasted_size = 0;
 196                                 if (VERYDIRTY(c, jeb->dirty_size)) {
 197                                         list_add(&jeb->list, &c->very_dirty_list);
 198                                 } else {
 199                                         list_add(&jeb->list, &c->dirty_list);
 200                                 }
 201                         }
 202                         break;
 203
 204                 case BLK_STATE_ALLDIRTY:
 205                         /* Nothing valid - not even a clean marker. Needs erasing. */
 206                         /* For now we just put it on the erasing list. We'll start the erases later */
 207                         D1(printk(KERN_NOTICE "JFFS2: Erase block at 0x%08x is not formatted. It will be erased\n", jeb->offset));
 208                         list_add(&jeb->list, &c->erase_pending_list);
 209                         c->nr_erasing_blocks++;
 210                         break;
 211
 212                 case BLK_STATE_BADBLOCK:
 213                         D1(printk(KERN_NOTICE "JFFS2: Block at 0x%08x is bad\n", jeb->offset));
 214                         list_add(&jeb->list, &c->bad_list);
 215                         c->bad_size += c->sector_size;
 216                         c->free_size -= c->sector_size;
 217                         bad_blocks++;
 218                         break;
 219                 default:
 220                         printk(KERN_WARNING "jffs2_scan_medium(): unknown block state\n");
 221                         BUG();
 222                 }
 223         }
 224
 225         /* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
 226         if (c->nextblock && (c->nextblock->dirty_size)) {
 227                 c->nextblock->wasted_size += c->nextblock->dirty_size;
 228                 c->wasted_size += c->nextblock->dirty_size;
 229                 c->dirty_size -= c->nextblock->dirty_size;
 230                 c->nextblock->dirty_size = 0;
 231         }
 232 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 233         if (!jffs2_can_mark_obsolete(c) && c->wbuf_pagesize && c->nextblock && (c->nextblock->free_size % c->wbuf_pagesize)) {
 234                 /* If we're going to start writing into a block which already
 235                    contains data, and the end of the data isn't page-aligned,
 236                    skip a little and align it. */
 237
 238                 uint32_t skip = c->nextblock->free_size % c->wbuf_pagesize;
 239
 240                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): Skipping %d bytes in nextblock to ensure page alignment\n",
 241                           skip));
 242                 c->nextblock->wasted_size += skip;
 243                 c->wasted_size += skip;
 244
 245                 c->nextblock->free_size -= skip;
 246                 c->free_size -= skip;
 247         }
 248 #endif
 249         if (c->nr_erasing_blocks) {
 250                 if ( !c->used_size && ((c->nr_free_blocks+empty_blocks+bad_blocks)!= c->nr_blocks || bad_blocks == c->nr_blocks) ) {
 251                         printk(KERN_NOTICE "Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
 252                         printk(KERN_NOTICE "empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",empty_blocks,bad_blocks,c->nr_blocks);
 253                         ret = -EIO;
 254                         goto out;
 255                 }
 256                 jffs2_erase_pending_trigger(c);
 257         }
 258         ret = 0;
 259  out:
 260         if (buf_size)
 261                 kfree(flashbuf);
 262 #ifndef __ECOS
 263         else
 264                 c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
 265 #endif
 266         if (s)
 267                 kfree(s);
 268
 269         return ret;
 270 }
 271
 272 int jffs2_fill_scan_buf (struct jffs2_sb_info *c, void *buf,
 273                                 uint32_t ofs, uint32_t len)
 274 {
 275         int ret;
 276         size_t retlen;
 277
 278         ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
 279         if (ret) {
 280                 D1(printk(KERN_WARNING "mtd->read(0x%x bytes from 0x%x) returned %d\n", len, ofs, ret));
 281                 return ret;
 282         }
 283         if (retlen < len) {
 284                 D1(printk(KERN_WARNING "Read at 0x%x gave only 0x%zx bytes\n", ofs, retlen));
 285                 return -EIO;
 286         }
 287         return 0;
 288 }
 289
 290 int jffs2_scan_classify_jeb(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
 291 {
 292         if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size
 293                 && (!jeb->first_node || !jeb->first_node->next_phys) )
 294                 return BLK_STATE_CLEANMARKER;
 295
 296         /* move blocks with max 4 byte dirty space to cleanlist */
 297         else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
 298                 c->dirty_size -= jeb->dirty_size;
 299                 c->wasted_size += jeb->dirty_size;
 300                 jeb->wasted_size += jeb->dirty_size;
 301                 jeb->dirty_size = 0;
 302                 return BLK_STATE_CLEAN;
 303         } else if (jeb->used_size || jeb->unchecked_size)
 304                 return BLK_STATE_PARTDIRTY;
 305         else
 306                 return BLK_STATE_ALLDIRTY;
 307 }
 308
 309 /* Called with 'buf_size == 0' if buf is in fact a pointer _directly_ into
 310    the flash, XIP-style */
 311 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 312                                   unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) {
 313         struct jffs2_unknown_node *node;
 314         struct jffs2_unknown_node crcnode;
 315         uint32_t ofs, prevofs;
 316         uint32_t hdr_crc, buf_ofs, buf_len;
 317         int err;
 318         int noise = 0;
 319
 320
 321 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 322         int cleanmarkerfound = 0;
 323 #endif
 324
 325         ofs = jeb->offset;
 326         prevofs = jeb->offset - 1;
 327
 328         D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs));
 329
 330 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 331         if (jffs2_cleanmarker_oob(c)) {
 332                 int ret = jffs2_check_nand_cleanmarker(c, jeb);
 333                 D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n",ret));
 334                 /* Even if it's not found, we still scan to see
 335                    if the block is empty. We use this information
 336                    to decide whether to erase it or not. */
 337                 switch (ret) {
 338                 case 0:         cleanmarkerfound = 1; break;
 339                 case 1:         break;
 340                 case 2:         return BLK_STATE_BADBLOCK;
 341                 case 3:         return BLK_STATE_ALLDIRTY; /* Block has failed to erase min. once */
 342                 default:        return ret;
 343                 }
 344         }
 345 #endif
 346
 347         if (jffs2_sum_active()) {
 348                 struct jffs2_sum_marker *sm;
 349                 void *sumptr = NULL;
 350                 uint32_t sumlen;
 351
 352                 if (!buf_size) {
 353                         /* XIP case. Just look, point at the summary if it's there */
 354                         sm = (void *)buf + jeb->offset - sizeof(*sm);
 355                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
 356                                 sumptr = buf + je32_to_cpu(sm->offset);
 357                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
 358                         }
 359                 } else {
 360                         /* If NAND flash, read a whole page of it. Else just the end */
 361                         if (c->wbuf_pagesize)
 362                                 buf_len = c->wbuf_pagesize;
 363                         else
 364                                 buf_len = sizeof(*sm);
 365
 366                         /* Read as much as we want into the _end_ of the preallocated buffer */
 367                         err = jffs2_fill_scan_buf(c, buf + buf_size - buf_len,
 368                                                   jeb->offset + c->sector_size - buf_len,
 369                                                   buf_len);
 370                         if (err)
 371                                 return err;
 372
 373                         sm = (void *)buf + buf_size - sizeof(*sm);
 374                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
 375                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
 376                                 sumptr = buf + buf_size - sumlen;
 377
 378                                 /* Now, make sure the summary itself is available */
 379                                 if (sumlen > buf_size) {
 380                                         /* Need to kmalloc for this. */
 381                                         sumptr = kmalloc(sumlen, GFP_KERNEL);
 382                                         if (!sumptr)
 383                                                 return -ENOMEM;
 384                                         memcpy(sumptr + sumlen - buf_len, buf + buf_size - buf_len, buf_len);
 385                                 }
 386                                 if (buf_len < sumlen) {
 387                                         /* Need to read more so that the entire summary node is present */
 388                                         err = jffs2_fill_scan_buf(c, sumptr,
 389                                                                   jeb->offset + c->sector_size - sumlen,
 390                                                                   sumlen - buf_len);
 391                                         if (err)
 392                                                 return err;
 393                                 }
 394                         }
 395
 396                 }
 397
 398                 if (sumptr) {
 399                         err = jffs2_sum_scan_sumnode(c, jeb, sumptr, sumlen, &pseudo_random);
 400                         if (err)
 401                                 return err;
 402                         if (buf_size && sumlen > buf_size)
 403                                 kfree(sumptr);
 404                 }
 405         }
 406
 407         buf_ofs = jeb->offset;
 408
 409         if (!buf_size) {
 410                 /* This is the XIP case -- we're reading _directly_ from the flash chip */
 411                 buf_len = c->sector_size;
 412         } else {
 413                 buf_len = EMPTY_SCAN_SIZE(c->sector_size);
 414                 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
 415                 if (err)
 416                         return err;
 417         }
 418
 419         /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
 420         ofs = 0;
 421
 422         /* Scan only 4KiB of 0xFF before declaring it's empty */
 423         while(ofs < EMPTY_SCAN_SIZE(c->sector_size) && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
 424                 ofs += 4;
 425
 426         if (ofs == EMPTY_SCAN_SIZE(c->sector_size)) {
 427 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 428                 if (jffs2_cleanmarker_oob(c)) {
 429                         /* scan oob, take care of cleanmarker */
 430                         int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
 431                         D2(printk(KERN_NOTICE "jffs2_check_oob_empty returned %d\n",ret));
 432                         switch (ret) {
 433                         case 0:         return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
 434                         case 1:         return BLK_STATE_ALLDIRTY;
 435                         default:        return ret;
 436                         }
 437                 }
 438 #endif
 439                 D1(printk(KERN_DEBUG "Block at 0x%08x is empty (erased)\n", jeb->offset));
 440                 if (c->cleanmarker_size == 0)
 441                         return BLK_STATE_CLEANMARKER;   /* don't bother with re-erase */
 442                 else
 443                         return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
 444         }
 445         if (ofs) {
 446                 D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset,
 447                           jeb->offset + ofs));
 448                 DIRTY_SPACE(ofs);
 449         }
 450
 451         /* Now ofs is a complete physical flash offset as it always was... */
 452         ofs += jeb->offset;
 453
 454         noise = 10;
 455
 456         dbg_summary("no summary found in jeb 0x%08x. Apply original scan.\n",jeb->offset);
 457
 458 scan_more:
 459         while(ofs < jeb->offset + c->sector_size) {
 460
 461                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 462
 463                 cond_resched();
 464
 465                 if (ofs & 3) {
 466                         printk(KERN_WARNING "Eep. ofs 0x%08x not word-aligned!\n", ofs);
 467                         ofs = PAD(ofs);
 468                         continue;
 469                 }
 470                 if (ofs == prevofs) {
 471                         printk(KERN_WARNING "ofs 0x%08x has already been seen. Skipping\n", ofs);
 472                         DIRTY_SPACE(4);
 473                         ofs += 4;
 474                         continue;
 475                 }
 476                 prevofs = ofs;
 477
 478                 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
 479                         D1(printk(KERN_DEBUG "Fewer than %zd bytes left to end of block. (%x+%x<%x+%zx) Not reading\n", sizeof(struct jffs2_unknown_node),
 480                                   jeb->offset, c->sector_size, ofs, sizeof(*node)));
 481                         DIRTY_SPACE((jeb->offset + c->sector_size)-ofs);
 482                         break;
 483                 }
 484
 485                 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
 486                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 487                         D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
 488                                   sizeof(struct jffs2_unknown_node), buf_len, ofs));
 489                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 490                         if (err)
 491                                 return err;
 492                         buf_ofs = ofs;
 493                 }
 494
 495                 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
 496
 497                 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
 498                         uint32_t inbuf_ofs;
 499                         uint32_t empty_start;
 500
 501                         empty_start = ofs;
 502                         ofs += 4;
 503
 504                         D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs));
 505                 more_empty:
 506                         inbuf_ofs = ofs - buf_ofs;
 507                         while (inbuf_ofs < buf_len) {
 508                                 if (*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff) {
 509                                         printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n",
 510                                                empty_start, ofs);
 511                                         DIRTY_SPACE(ofs-empty_start);
 512                                         goto scan_more;
 513                                 }
 514
 515                                 inbuf_ofs+=4;
 516                                 ofs += 4;
 517                         }
 518                         /* Ran off end. */
 519                         D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs));
 520
 521                         /* If we're only checking the beginning of a block with a cleanmarker,
 522                            bail now */
 523                         if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&
 524                             c->cleanmarker_size && !jeb->dirty_size && !jeb->first_node->next_phys) {
 525                                 D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE(c->sector_size)));
 526                                 return BLK_STATE_CLEANMARKER;
 527                         }
 528
 529                         /* See how much more there is to read in this eraseblock... */
 530                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 531                         if (!buf_len) {
 532                                 /* No more to read. Break out of main loop without marking
 533                                    this range of empty space as dirty (because it's not) */
 534                                 D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block. Treating as free_space\n",
 535                                           empty_start));
 536                                 break;
 537                         }
 538                         D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs));
 539                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 540                         if (err)
 541                                 return err;
 542                         buf_ofs = ofs;
 543                         goto more_empty;
 544                 }
 545
 546                 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
 547                         printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n", ofs);
 548                         DIRTY_SPACE(4);
 549                         ofs += 4;
 550                         continue;
 551                 }
 552                 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
 553                         D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs));
 554                         DIRTY_SPACE(4);
 555                         ofs += 4;
 556                         continue;
 557                 }
 558                 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
 559                         printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08x\n", ofs);
 560                         printk(KERN_WARNING "You cannot use older JFFS2 filesystems with newer kernels\n");
 561                         DIRTY_SPACE(4);
 562                         ofs += 4;
 563                         continue;
 564                 }
 565                 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
 566                         /* OK. We're out of possibilities. Whinge and move on */
 567                         noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n",
 568                                      JFFS2_MAGIC_BITMASK, ofs,
 569                                      je16_to_cpu(node->magic));
 570                         DIRTY_SPACE(4);
 571                         ofs += 4;
 572                         continue;
 573                 }
 574                 /* We seem to have a node of sorts. Check the CRC */
 575                 crcnode.magic = node->magic;
 576                 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
 577                 crcnode.totlen = node->totlen;
 578                 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
 579
 580                 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
 581                         noisy_printk(&noise, "jffs2_scan_eraseblock(): Node at 0x%08x {0x%04x, 0x%04x, 0x%08x) has invalid CRC 0x%08x (calculated 0x%08x)\n",
 582                                      ofs, je16_to_cpu(node->magic),
 583                                      je16_to_cpu(node->nodetype),
 584                                      je32_to_cpu(node->totlen),
 585                                      je32_to_cpu(node->hdr_crc),
 586                                      hdr_crc);
 587                         DIRTY_SPACE(4);
 588                         ofs += 4;
 589                         continue;
 590                 }
 591
 592                 if (ofs + je32_to_cpu(node->totlen) >
 593                     jeb->offset + c->sector_size) {
 594                         /* Eep. Node goes over the end of the erase block. */
 595                         printk(KERN_WARNING "Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
 596                                ofs, je32_to_cpu(node->totlen));
 597                         printk(KERN_WARNING "Perhaps the file system was created with the wrong erase size?\n");
 598                         DIRTY_SPACE(4);
 599                         ofs += 4;
 600                         continue;
 601                 }
 602
 603                 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
 604                         /* Wheee. This is an obsoleted node */
 605                         D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs));
 606                         DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 607                         ofs += PAD(je32_to_cpu(node->totlen));
 608                         continue;
 609                 }
 610
 611                 switch(je16_to_cpu(node->nodetype)) {
 612                 case JFFS2_NODETYPE_INODE:
 613                         if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
 614                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 615                                 D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
 616                                           sizeof(struct jffs2_raw_inode), buf_len, ofs));
 617                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 618                                 if (err)
 619                                         return err;
 620                                 buf_ofs = ofs;
 621                                 node = (void *)buf;
 622                         }
 623                         err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs, s);
 624                         if (err) return err;
 625                         ofs += PAD(je32_to_cpu(node->totlen));
 626                         break;
 627
 628                 case JFFS2_NODETYPE_DIRENT:
 629                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 630                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 631                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
 632                                           je32_to_cpu(node->totlen), buf_len, ofs));
 633                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 634                                 if (err)
 635                                         return err;
 636                                 buf_ofs = ofs;
 637                                 node = (void *)buf;
 638                         }
 639                         err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs, s);
 640                         if (err) return err;
 641                         ofs += PAD(je32_to_cpu(node->totlen));
 642                         break;
 643
 644                 case JFFS2_NODETYPE_CLEANMARKER:
 645                         D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs));
 646                         if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
 647                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n",
 648                                        ofs, je32_to_cpu(node->totlen), c->cleanmarker_size);
 649                                 DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
 650                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 651                         } else if (jeb->first_node) {
 652                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n", ofs, jeb->offset);
 653                                 DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
 654                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 655                         } else {
 656                                 struct jffs2_raw_node_ref *marker_ref = jffs2_alloc_raw_node_ref();
 657                                 if (!marker_ref) {
 658                                         printk(KERN_NOTICE "Failed to allocate node ref for clean marker\n");
 659                                         return -ENOMEM;
 660                                 }
 661                                 marker_ref->next_in_ino = NULL;
 662                                 marker_ref->next_phys = NULL;
 663                                 marker_ref->flash_offset = ofs | REF_NORMAL;
 664                                 marker_ref->__totlen = c->cleanmarker_size;
 665                                 jeb->first_node = jeb->last_node = marker_ref;
 666
 667                                 USED_SPACE(PAD(c->cleanmarker_size));
 668                                 ofs += PAD(c->cleanmarker_size);
 669                         }
 670                         break;
 671
 672                 case JFFS2_NODETYPE_PADDING:
 673                         if (jffs2_sum_active())
 674                                 jffs2_sum_add_padding_mem(s, je32_to_cpu(node->totlen));
 675                         DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 676                         ofs += PAD(je32_to_cpu(node->totlen));
 677                         break;
 678
 679                 default:
 680                         switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
 681                         case JFFS2_FEATURE_ROCOMPAT:
 682                                 printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 683                                 c->flags |= JFFS2_SB_FLAG_RO;
 684                                 if (!(jffs2_is_readonly(c)))
 685                                         return -EROFS;
 686                                 DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 687                                 ofs += PAD(je32_to_cpu(node->totlen));
 688                                 break;
 689
 690                         case JFFS2_FEATURE_INCOMPAT:
 691                                 printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
 692                                 return -EINVAL;
 693
 694                         case JFFS2_FEATURE_RWCOMPAT_DELETE:
 695                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 696                                 DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
 697                                 ofs += PAD(je32_to_cpu(node->totlen));
 698                                 break;
 699
 700                         case JFFS2_FEATURE_RWCOMPAT_COPY:
 701                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
 702                                 USED_SPACE(PAD(je32_to_cpu(node->totlen)));
 703                                 ofs += PAD(je32_to_cpu(node->totlen));
 704                                 break;
 705                         }
 706                 }
 707         }
 708
 709         if (jffs2_sum_active()) {
 710                 if (PAD(s->sum_size + JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size) {
 711                         dbg_summary("There is not enough space for "
 712                                 "summary information, disabling for this jeb!\n");
 713                         jffs2_sum_disable_collecting(s);
 714                 }
 715         }
 716
 717         D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x\n", jeb->offset,
 718                   jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size));
 719
 720         /* mark_node_obsolete can add to wasted !! */
 721         if (jeb->wasted_size) {
 722                 jeb->dirty_size += jeb->wasted_size;
 723                 c->dirty_size += jeb->wasted_size;
 724                 c->wasted_size -= jeb->wasted_size;
 725                 jeb->wasted_size = 0;
 726         }
 727
 728         return jffs2_scan_classify_jeb(c, jeb);
 729 }
 730
 731 struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
 732 {
 733         struct jffs2_inode_cache *ic;
 734
 735         ic = jffs2_get_ino_cache(c, ino);
 736         if (ic)
 737                 return ic;
 738
 739         if (ino > c->highest_ino)
 740                 c->highest_ino = ino;
 741
 742         ic = jffs2_alloc_inode_cache();
 743         if (!ic) {
 744                 printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n");
 745                 return NULL;
 746         }
 747         memset(ic, 0, sizeof(*ic));
 748
 749         ic->ino = ino;
 750         ic->nodes = (void *)ic;
 751         jffs2_add_ino_cache(c, ic);
 752         if (ino == 1)
 753                 ic->nlink = 1;
 754         return ic;
 755 }
 756
 757 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 758                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s)
 759 {
 760         struct jffs2_raw_node_ref *raw;
 761         struct jffs2_inode_cache *ic;
 762         uint32_t ino = je32_to_cpu(ri->ino);
 763
 764         D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs));
 765
 766         /* We do very little here now. Just check the ino# to which we should attribute
 767            this node; we can do all the CRC checking etc. later. There's a tradeoff here --
 768            we used to scan the flash once only, reading everything we want from it into
 769            memory, then building all our in-core data structures and freeing the extra
 770            information. Now we allow the first part of the mount to complete a lot quicker,
 771            but we have to go _back_ to the flash in order to finish the CRC checking, etc.
 772            Which means that the _full_ amount of time to get to proper write mode with GC
 773            operational may actually be _longer_ than before. Sucks to be me. */
 774
 775         raw = jffs2_alloc_raw_node_ref();
 776         if (!raw) {
 777                 printk(KERN_NOTICE "jffs2_scan_inode_node(): allocation of node reference failed\n");
 778                 return -ENOMEM;
 779         }
 780
 781         ic = jffs2_get_ino_cache(c, ino);
 782         if (!ic) {
 783                 /* Inocache get failed. Either we read a bogus ino# or it's just genuinely the
 784                    first node we found for this inode. Do a CRC check to protect against the former
 785                    case */
 786                 uint32_t crc = crc32(0, ri, sizeof(*ri)-8);
 787
 788                 if (crc != je32_to_cpu(ri->node_crc)) {
 789                         printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 790                                ofs, je32_to_cpu(ri->node_crc), crc);
 791                         /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
 792                         DIRTY_SPACE(PAD(je32_to_cpu(ri->totlen)));
 793                         jffs2_free_raw_node_ref(raw);
 794                         return 0;
 795                 }
 796                 ic = jffs2_scan_make_ino_cache(c, ino);
 797                 if (!ic) {
 798                         jffs2_free_raw_node_ref(raw);
 799                         return -ENOMEM;
 800                 }
 801         }
 802
 803         /* Wheee. It worked */
 804
 805         raw->flash_offset = ofs | REF_UNCHECKED;
 806         raw->__totlen = PAD(je32_to_cpu(ri->totlen));
 807         raw->next_phys = NULL;
 808         raw->next_in_ino = ic->nodes;
 809
 810         ic->nodes = raw;
 811         if (!jeb->first_node)
 812                 jeb->first_node = raw;
 813         if (jeb->last_node)
 814                 jeb->last_node->next_phys = raw;
 815         jeb->last_node = raw;
 816
 817         D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
 818                   je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
 819                   je32_to_cpu(ri->offset),
 820                   je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize)));
 821
 822         pseudo_random += je32_to_cpu(ri->version);
 823
 824         UNCHECKED_SPACE(PAD(je32_to_cpu(ri->totlen)));
 825
 826         if (jffs2_sum_active()) {
 827                 jffs2_sum_add_inode_mem(s, ri, ofs - jeb->offset);
 828         }
 829
 830         return 0;
 831 }
 832
 833 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 834                                   struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s)
 835 {
 836         struct jffs2_raw_node_ref *raw;
 837         struct jffs2_full_dirent *fd;
 838         struct jffs2_inode_cache *ic;
 839         uint32_t crc;
 840
 841         D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs));
 842
 843         /* We don't get here unless the node is still valid, so we don't have to
 844            mask in the ACCURATE bit any more. */
 845         crc = crc32(0, rd, sizeof(*rd)-8);
 846
 847         if (crc != je32_to_cpu(rd->node_crc)) {
 848                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 849                        ofs, je32_to_cpu(rd->node_crc), crc);
 850                 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
 851                 DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
 852                 return 0;
 853         }
 854
 855         pseudo_random += je32_to_cpu(rd->version);
 856
 857         fd = jffs2_alloc_full_dirent(rd->nsize+1);
 858         if (!fd) {
 859                 return -ENOMEM;
 860         }
 861         memcpy(&fd->name, rd->name, rd->nsize);
 862         fd->name[rd->nsize] = 0;
 863
 864         crc = crc32(0, fd->name, rd->nsize);
 865         if (crc != je32_to_cpu(rd->name_crc)) {
 866                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 867                        ofs, je32_to_cpu(rd->name_crc), crc);
 868                 D1(printk(KERN_NOTICE "Name for which CRC failed is (now) '%s', ino #%d\n", fd->name, je32_to_cpu(rd->ino)));
 869                 jffs2_free_full_dirent(fd);
 870                 /* FIXME: Why do we believe totlen? */
 871                 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
 872                 DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
 873                 return 0;
 874         }
 875         raw = jffs2_alloc_raw_node_ref();
 876         if (!raw) {
 877                 jffs2_free_full_dirent(fd);
 878                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): allocation of node reference failed\n");
 879                 return -ENOMEM;
 880         }
 881         ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
 882         if (!ic) {
 883                 jffs2_free_full_dirent(fd);
 884                 jffs2_free_raw_node_ref(raw);
 885                 return -ENOMEM;
 886         }
 887
 888         raw->__totlen = PAD(je32_to_cpu(rd->totlen));
 889         raw->flash_offset = ofs | REF_PRISTINE;
 890         raw->next_phys = NULL;
 891         raw->next_in_ino = ic->nodes;
 892         ic->nodes = raw;
 893         if (!jeb->first_node)
 894                 jeb->first_node = raw;
 895         if (jeb->last_node)
 896                 jeb->last_node->next_phys = raw;
 897         jeb->last_node = raw;
 898
 899         fd->raw = raw;
 900         fd->next = NULL;
 901         fd->version = je32_to_cpu(rd->version);
 902         fd->ino = je32_to_cpu(rd->ino);
 903         fd->nhash = full_name_hash(fd->name, rd->nsize);
 904         fd->type = rd->type;
 905         USED_SPACE(PAD(je32_to_cpu(rd->totlen)));
 906         jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
 907
 908         if (jffs2_sum_active()) {
 909                 jffs2_sum_add_dirent_mem(s, rd, ofs - jeb->offset);
 910         }
 911
 912         return 0;
 913 }
 914
 915 static int count_list(struct list_head *l)
 916 {
 917         uint32_t count = 0;
 918         struct list_head *tmp;
 919
 920         list_for_each(tmp, l) {
 921                 count++;
 922         }
 923         return count;
 924 }
 925
 926 /* Note: This breaks if list_empty(head). I don't care. You
 927    might, if you copy this code and use it elsewhere :) */
 928 static void rotate_list(struct list_head *head, uint32_t count)
 929 {
 930         struct list_head *n = head->next;
 931
 932         list_del(head);
 933         while(count--) {
 934                 n = n->next;
 935         }
 936         list_add(head, n);
 937 }
 938
 939 void jffs2_rotate_lists(struct jffs2_sb_info *c)
 940 {
 941         uint32_t x;
 942         uint32_t rotateby;
 943
 944         x = count_list(&c->clean_list);
 945         if (x) {
 946                 rotateby = pseudo_random % x;
 947                 rotate_list((&c->clean_list), rotateby);
 948         }
 949
 950         x = count_list(&c->very_dirty_list);
 951         if (x) {
 952                 rotateby = pseudo_random % x;
 953                 rotate_list((&c->very_dirty_list), rotateby);
 954         }
 955
 956         x = count_list(&c->dirty_list);
 957         if (x) {
 958                 rotateby = pseudo_random % x;
 959                 rotate_list((&c->dirty_list), rotateby);
 960         }
 961
 962         x = count_list(&c->erasable_list);
 963         if (x) {
 964                 rotateby = pseudo_random % x;
 965                 rotate_list((&c->erasable_list), rotateby);
 966         }
 967
 968         if (c->nr_erasing_blocks) {
 969                 rotateby = pseudo_random % c->nr_erasing_blocks;
 970                 rotate_list((&c->erase_pending_list), rotateby);
 971         }
 972
 973         if (c->nr_free_blocks) {
 974                 rotateby = pseudo_random % c->nr_free_blocks;
 975                 rotate_list((&c->free_list), rotateby);
 976         }
 977 }