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

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