fs/jffs2/scan.c

   1 /*
   2  * JFFS2 -- Journalling Flash File System, Version 2.
   3  *
   4  * Copyright © 2001-2007 Red Hat, Inc.
   5  *
   6  * Created by David Woodhouse <dwmw2@infradead.org>
   7  *
   8  * For licensing information, see the file 'LICENCE' in this directory.
   9  *
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/kernel.h>
  15 #include <linux/sched.h>
  16 #include <linux/slab.h>
  17 #include <linux/mtd/mtd.h>
  18 #include <linux/pagemap.h>
  19 #include <linux/crc32.h>
  20 #include <linux/compiler.h>
  21 #include "nodelist.h"
  22 #include "summary.h"
  23 #include "debug.h"
  24
  25 #define DEFAULT_EMPTY_SCAN_SIZE 256
  26
  27 #define noisy_printk(noise, fmt, ...)                                   \
  28 do {                                                                    \
  29         if (*(noise)) {                                                 \
  30                 pr_notice(fmt, ##__VA_ARGS__);                          \
  31                 (*(noise))--;                                           \
  32                 if (!(*(noise)))                                        \
  33                         pr_notice("Further such events for this erase block will not be printed\n"); \
  34         }                                                               \
  35 } while (0)
  36
  37 static uint32_t pseudo_random;
  38
  39 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  40                                   unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s);
  41
  42 /* These helper functions _must_ increase ofs and also do the dirty/used space accounting.
  43  * Returning an error will abort the mount - bad checksums etc. should just mark the space
  44  * as dirty.
  45  */
  46 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  47                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s);
  48 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  49                                  struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s);
  50
  51 static inline int min_free(struct jffs2_sb_info *c)
  52 {
  53         uint32_t min = 2 * sizeof(struct jffs2_raw_inode);
  54 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
  55         if (!jffs2_can_mark_obsolete(c) && min < c->wbuf_pagesize)
  56                 return c->wbuf_pagesize;
  57 #endif
  58         return min;
  59
  60 }
  61
  62 static inline uint32_t EMPTY_SCAN_SIZE(uint32_t sector_size) {
  63         if (sector_size < DEFAULT_EMPTY_SCAN_SIZE)
  64                 return sector_size;
  65         else
  66                 return DEFAULT_EMPTY_SCAN_SIZE;
  67 }
  68
  69 static int file_dirty(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
  70 {
  71         int ret;
  72
  73         if ((ret = jffs2_prealloc_raw_node_refs(c, jeb, 1)))
  74                 return ret;
  75         if ((ret = jffs2_scan_dirty_space(c, jeb, jeb->free_size)))
  76                 return ret;
  77         /* Turned wasted size into dirty, since we apparently
  78            think it's recoverable now. */
  79         jeb->dirty_size += jeb->wasted_size;
  80         c->dirty_size += jeb->wasted_size;
  81         c->wasted_size -= jeb->wasted_size;
  82         jeb->wasted_size = 0;
  83         if (VERYDIRTY(c, jeb->dirty_size)) {
  84                 list_add(&jeb->list, &c->very_dirty_list);
  85         } else {
  86                 list_add(&jeb->list, &c->dirty_list);
  87         }
  88         return 0;
  89 }
  90
  91 int jffs2_scan_medium(struct jffs2_sb_info *c)
  92 {
  93         int i, ret;
  94         uint32_t empty_blocks = 0, bad_blocks = 0;
  95         unsigned char *flashbuf = NULL;
  96         uint32_t buf_size = 0;
  97         struct jffs2_summary *s = NULL; /* summary info collected by the scan process */
  98 #ifndef __ECOS
  99         size_t pointlen, try_size;
 100
 101         ret = mtd_point(c->mtd, 0, c->mtd->size, &pointlen,
 102                         (void **)&flashbuf, NULL);
 103         if (!ret && pointlen < c->mtd->size) {
 104                 /* Don't muck about if it won't let us point to the whole flash */
 105                 jffs2_dbg(1, "MTD point returned len too short: 0x%zx\n",
 106                           pointlen);
 107                 mtd_unpoint(c->mtd, 0, pointlen);
 108                 flashbuf = NULL;
 109         }
 110         if (ret && ret != -EOPNOTSUPP)
 111                 jffs2_dbg(1, "MTD point failed %d\n", ret);
 112 #endif
 113         if (!flashbuf) {
 114                 /* For NAND it's quicker to read a whole eraseblock at a time,
 115                    apparently */
 116                 if (jffs2_cleanmarker_oob(c))
 117                         try_size = c->sector_size;
 118                 else
 119                         try_size = PAGE_SIZE;
 120
 121                 jffs2_dbg(1, "Trying to allocate readbuf of %zu "
 122                           "bytes\n", try_size);
 123
 124                 flashbuf = mtd_kmalloc_up_to(c->mtd, &try_size);
 125                 if (!flashbuf)
 126                         return -ENOMEM;
 127
 128                 jffs2_dbg(1, "Allocated readbuf of %zu bytes\n",
 129                           try_size);
 130
 131                 buf_size = (uint32_t)try_size;
 132         }
 133
 134         if (jffs2_sum_active()) {
 135                 s = kzalloc(sizeof(struct jffs2_summary), GFP_KERNEL);
 136                 if (!s) {
 137                         JFFS2_WARNING("Can't allocate memory for summary\n");
 138                         ret = -ENOMEM;
 139                         goto out_buf;
 140                 }
 141         }
 142
 143         for (i=0; i<c->nr_blocks; i++) {
 144                 struct jffs2_eraseblock *jeb = &c->blocks[i];
 145
 146                 cond_resched();
 147
 148                 /* reset summary info for next eraseblock scan */
 149                 jffs2_sum_reset_collected(s);
 150
 151                 ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset),
 152                                                 buf_size, s);
 153
 154                 if (ret < 0)
 155                         goto out;
 156
 157                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 158
 159                 /* Now decide which list to put it on */
 160                 switch(ret) {
 161                 case BLK_STATE_ALLFF:
 162                         /*
 163                          * Empty block.   Since we can't be sure it
 164                          * was entirely erased, we just queue it for erase
 165                          * again.  It will be marked as such when the erase
 166                          * is complete.  Meanwhile we still count it as empty
 167                          * for later checks.
 168                          */
 169                         empty_blocks++;
 170                         list_add(&jeb->list, &c->erase_pending_list);
 171                         c->nr_erasing_blocks++;
 172                         break;
 173
 174                 case BLK_STATE_CLEANMARKER:
 175                         /* Only a CLEANMARKER node is valid */
 176                         if (!jeb->dirty_size) {
 177                                 /* It's actually free */
 178                                 list_add(&jeb->list, &c->free_list);
 179                                 c->nr_free_blocks++;
 180                         } else {
 181                                 /* Dirt */
 182                                 jffs2_dbg(1, "Adding all-dirty block at 0x%08x to erase_pending_list\n",
 183                                           jeb->offset);
 184                                 list_add(&jeb->list, &c->erase_pending_list);
 185                                 c->nr_erasing_blocks++;
 186                         }
 187                         break;
 188
 189                 case BLK_STATE_CLEAN:
 190                         /* Full (or almost full) of clean data. Clean list */
 191                         list_add(&jeb->list, &c->clean_list);
 192                         break;
 193
 194                 case BLK_STATE_PARTDIRTY:
 195                         /* Some data, but not full. Dirty list. */
 196                         /* We want to remember the block with most free space
 197                         and stick it in the 'nextblock' position to start writing to it. */
 198                         if (jeb->free_size > min_free(c) &&
 199                                         (!c->nextblock || c->nextblock->free_size < jeb->free_size)) {
 200                                 /* Better candidate for the next writes to go to */
 201                                 if (c->nextblock) {
 202                                         ret = file_dirty(c, c->nextblock);
 203                                         if (ret)
 204                                                 goto out;
 205                                         /* deleting summary information of the old nextblock */
 206                                         jffs2_sum_reset_collected(c->summary);
 207                                 }
 208                                 /* update collected summary information for the current nextblock */
 209                                 jffs2_sum_move_collected(c, s);
 210                                 jffs2_dbg(1, "%s(): new nextblock = 0x%08x\n",
 211                                           __func__, jeb->offset);
 212                                 c->nextblock = jeb;
 213                         } else {
 214                                 ret = file_dirty(c, jeb);
 215                                 if (ret)
 216                                         goto out;
 217                         }
 218                         break;
 219
 220                 case BLK_STATE_ALLDIRTY:
 221                         /* Nothing valid - not even a clean marker. Needs erasing. */
 222                         /* For now we just put it on the erasing list. We'll start the erases later */
 223                         jffs2_dbg(1, "Erase block at 0x%08x is not formatted. It will be erased\n",
 224                                   jeb->offset);
 225                         list_add(&jeb->list, &c->erase_pending_list);
 226                         c->nr_erasing_blocks++;
 227                         break;
 228
 229                 case BLK_STATE_BADBLOCK:
 230                         jffs2_dbg(1, "Block at 0x%08x is bad\n", jeb->offset);
 231                         list_add(&jeb->list, &c->bad_list);
 232                         c->bad_size += c->sector_size;
 233                         c->free_size -= c->sector_size;
 234                         bad_blocks++;
 235                         break;
 236                 default:
 237                         pr_warn("%s(): unknown block state\n", __func__);
 238                         BUG();
 239                 }
 240         }
 241
 242         /* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
 243         if (c->nextblock && (c->nextblock->dirty_size)) {
 244                 c->nextblock->wasted_size += c->nextblock->dirty_size;
 245                 c->wasted_size += c->nextblock->dirty_size;
 246                 c->dirty_size -= c->nextblock->dirty_size;
 247                 c->nextblock->dirty_size = 0;
 248         }
 249 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 250         if (!jffs2_can_mark_obsolete(c) && c->wbuf_pagesize && c->nextblock && (c->nextblock->free_size % c->wbuf_pagesize)) {
 251                 /* If we're going to start writing into a block which already
 252                    contains data, and the end of the data isn't page-aligned,
 253                    skip a little and align it. */
 254
 255                 uint32_t skip = c->nextblock->free_size % c->wbuf_pagesize;
 256
 257                 jffs2_dbg(1, "%s(): Skipping %d bytes in nextblock to ensure page alignment\n",
 258                           __func__, skip);
 259                 jffs2_prealloc_raw_node_refs(c, c->nextblock, 1);
 260                 jffs2_scan_dirty_space(c, c->nextblock, skip);
 261         }
 262 #endif
 263         if (c->nr_erasing_blocks) {
 264                 if (!c->used_size && !c->unchecked_size &&
 265                         ((c->nr_free_blocks+empty_blocks+bad_blocks) != c->nr_blocks || bad_blocks == c->nr_blocks)) {
 266                         pr_notice("Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
 267                         pr_notice("empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",
 268                                   empty_blocks, bad_blocks, c->nr_blocks);
 269                         ret = -EIO;
 270                         goto out;
 271                 }
 272                 spin_lock(&c->erase_completion_lock);
 273                 jffs2_garbage_collect_trigger(c);
 274                 spin_unlock(&c->erase_completion_lock);
 275         }
 276         ret = 0;
 277  out:
 278         jffs2_sum_reset_collected(s);
 279         kfree(s);
 280  out_buf:
 281         if (buf_size)
 282                 kfree(flashbuf);
 283 #ifndef __ECOS
 284         else
 285                 mtd_unpoint(c->mtd, 0, c->mtd->size);
 286 #endif
 287         return ret;
 288 }
 289
 290 static int jffs2_fill_scan_buf(struct jffs2_sb_info *c, void *buf,
 291                                uint32_t ofs, uint32_t len)
 292 {
 293         int ret;
 294         size_t retlen;
 295
 296         ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
 297         if (ret) {
 298                 jffs2_dbg(1, "mtd->read(0x%x bytes from 0x%x) returned %d\n",
 299                           len, ofs, ret);
 300                 return ret;
 301         }
 302         if (retlen < len) {
 303                 jffs2_dbg(1, "Read at 0x%x gave only 0x%zx bytes\n",
 304                           ofs, retlen);
 305                 return -EIO;
 306         }
 307         return 0;
 308 }
 309
 310 int jffs2_scan_classify_jeb(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
 311 {
 312         if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size
 313             && (!jeb->first_node || !ref_next(jeb->first_node)) )
 314                 return BLK_STATE_CLEANMARKER;
 315
 316         /* move blocks with max 4 byte dirty space to cleanlist */
 317         else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
 318                 c->dirty_size -= jeb->dirty_size;
 319                 c->wasted_size += jeb->dirty_size;
 320                 jeb->wasted_size += jeb->dirty_size;
 321                 jeb->dirty_size = 0;
 322                 return BLK_STATE_CLEAN;
 323         } else if (jeb->used_size || jeb->unchecked_size)
 324                 return BLK_STATE_PARTDIRTY;
 325         else
 326                 return BLK_STATE_ALLDIRTY;
 327 }
 328
 329 #ifdef CONFIG_JFFS2_FS_XATTR
 330 static int jffs2_scan_xattr_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 331                                  struct jffs2_raw_xattr *rx, uint32_t ofs,
 332                                  struct jffs2_summary *s)
 333 {
 334         struct jffs2_xattr_datum *xd;
 335         uint32_t xid, version, totlen, crc;
 336         int err;
 337
 338         crc = crc32(0, rx, sizeof(struct jffs2_raw_xattr) - 4);
 339         if (crc != je32_to_cpu(rx->node_crc)) {
 340                 JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
 341                               ofs, je32_to_cpu(rx->node_crc), crc);
 342                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
 343                         return err;
 344                 return 0;
 345         }
 346
 347         xid = je32_to_cpu(rx->xid);
 348         version = je32_to_cpu(rx->version);
 349
 350         totlen = PAD(sizeof(struct jffs2_raw_xattr)
 351                         + rx->name_len + 1 + je16_to_cpu(rx->value_len));
 352         if (totlen != je32_to_cpu(rx->totlen)) {
 353                 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%u\n",
 354                               ofs, je32_to_cpu(rx->totlen), totlen);
 355                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
 356                         return err;
 357                 return 0;
 358         }
 359
 360         xd = jffs2_setup_xattr_datum(c, xid, version);
 361         if (IS_ERR(xd))
 362                 return PTR_ERR(xd);
 363
 364         if (xd->version > version) {
 365                 struct jffs2_raw_node_ref *raw
 366                         = jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, NULL);
 367                 raw->next_in_ino = xd->node->next_in_ino;
 368                 xd->node->next_in_ino = raw;
 369         } else {
 370                 xd->version = version;
 371                 xd->xprefix = rx->xprefix;
 372                 xd->name_len = rx->name_len;
 373                 xd->value_len = je16_to_cpu(rx->value_len);
 374                 xd->data_crc = je32_to_cpu(rx->data_crc);
 375
 376                 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, (void *)xd);
 377         }
 378
 379         if (jffs2_sum_active())
 380                 jffs2_sum_add_xattr_mem(s, rx, ofs - jeb->offset);
 381         dbg_xattr("scanning xdatum at %#08x (xid=%u, version=%u)\n",
 382                   ofs, xd->xid, xd->version);
 383         return 0;
 384 }
 385
 386 static int jffs2_scan_xref_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 387                                 struct jffs2_raw_xref *rr, uint32_t ofs,
 388                                 struct jffs2_summary *s)
 389 {
 390         struct jffs2_xattr_ref *ref;
 391         uint32_t crc;
 392         int err;
 393
 394         crc = crc32(0, rr, sizeof(*rr) - 4);
 395         if (crc != je32_to_cpu(rr->node_crc)) {
 396                 JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
 397                               ofs, je32_to_cpu(rr->node_crc), crc);
 398                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rr->totlen)))))
 399                         return err;
 400                 return 0;
 401         }
 402
 403         if (PAD(sizeof(struct jffs2_raw_xref)) != je32_to_cpu(rr->totlen)) {
 404                 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%zd\n",
 405                               ofs, je32_to_cpu(rr->totlen),
 406                               PAD(sizeof(struct jffs2_raw_xref)));
 407                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rr->totlen))))
 408                         return err;
 409                 return 0;
 410         }
 411
 412         ref = jffs2_alloc_xattr_ref();
 413         if (!ref)
 414                 return -ENOMEM;
 415
 416         /* BEFORE jffs2_build_xattr_subsystem() called,
 417          * and AFTER xattr_ref is marked as a dead xref,
 418          * ref->xid is used to store 32bit xid, xd is not used
 419          * ref->ino is used to store 32bit inode-number, ic is not used
 420          * Thoes variables are declared as union, thus using those
 421          * are exclusive. In a similar way, ref->next is temporarily
 422          * used to chain all xattr_ref object. It's re-chained to
 423          * jffs2_inode_cache in jffs2_build_xattr_subsystem() correctly.
 424          */
 425         ref->ino = je32_to_cpu(rr->ino);
 426         ref->xid = je32_to_cpu(rr->xid);
 427         ref->xseqno = je32_to_cpu(rr->xseqno);
 428         if (ref->xseqno > c->highest_xseqno)
 429                 c->highest_xseqno = (ref->xseqno & ~XREF_DELETE_MARKER);
 430         ref->next = c->xref_temp;
 431         c->xref_temp = ref;
 432
 433         jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(rr->totlen)), (void *)ref);
 434
 435         if (jffs2_sum_active())
 436                 jffs2_sum_add_xref_mem(s, rr, ofs - jeb->offset);
 437         dbg_xattr("scan xref at %#08x (xid=%u, ino=%u)\n",
 438                   ofs, ref->xid, ref->ino);
 439         return 0;
 440 }
 441 #endif
 442
 443 /* Called with 'buf_size == 0' if buf is in fact a pointer _directly_ into
 444    the flash, XIP-style */
 445 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 446                                   unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) {
 447         struct jffs2_unknown_node *node;
 448         struct jffs2_unknown_node crcnode;
 449         uint32_t ofs, prevofs, max_ofs;
 450         uint32_t hdr_crc, buf_ofs, buf_len;
 451         int err;
 452         int noise = 0;
 453
 454
 455 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 456         int cleanmarkerfound = 0;
 457 #endif
 458
 459         ofs = jeb->offset;
 460         prevofs = jeb->offset - 1;
 461
 462         jffs2_dbg(1, "%s(): Scanning block at 0x%x\n", __func__, ofs);
 463
 464 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 465         if (jffs2_cleanmarker_oob(c)) {
 466                 int ret;
 467
 468                 if (mtd_block_isbad(c->mtd, jeb->offset))
 469                         return BLK_STATE_BADBLOCK;
 470
 471                 ret = jffs2_check_nand_cleanmarker(c, jeb);
 472                 jffs2_dbg(2, "jffs_check_nand_cleanmarker returned %d\n", ret);
 473
 474                 /* Even if it's not found, we still scan to see
 475                    if the block is empty. We use this information
 476                    to decide whether to erase it or not. */
 477                 switch (ret) {
 478                 case 0:         cleanmarkerfound = 1; break;
 479                 case 1:         break;
 480                 default:        return ret;
 481                 }
 482         }
 483 #endif
 484
 485         if (jffs2_sum_active()) {
 486                 struct jffs2_sum_marker *sm;
 487                 void *sumptr = NULL;
 488                 uint32_t sumlen;
 489
 490                 if (!buf_size) {
 491                         /* XIP case. Just look, point at the summary if it's there */
 492                         sm = (void *)buf + c->sector_size - sizeof(*sm);
 493                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
 494                                 sumptr = buf + je32_to_cpu(sm->offset);
 495                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
 496                         }
 497                 } else {
 498                         /* If NAND flash, read a whole page of it. Else just the end */
 499                         if (c->wbuf_pagesize)
 500                                 buf_len = c->wbuf_pagesize;
 501                         else
 502                                 buf_len = sizeof(*sm);
 503
 504                         /* Read as much as we want into the _end_ of the preallocated buffer */
 505                         err = jffs2_fill_scan_buf(c, buf + buf_size - buf_len,
 506                                                   jeb->offset + c->sector_size - buf_len,
 507                                                   buf_len);
 508                         if (err)
 509                                 return err;
 510
 511                         sm = (void *)buf + buf_size - sizeof(*sm);
 512                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
 513                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
 514                                 sumptr = buf + buf_size - sumlen;
 515
 516                                 /* sm->offset maybe wrong but MAGIC maybe right */
 517                                 if (sumlen > c->sector_size)
 518                                         goto full_scan;
 519
 520                                 /* Now, make sure the summary itself is available */
 521                                 if (sumlen > buf_size) {
 522                                         /* Need to kmalloc for this. */
 523                                         sumptr = kmalloc(sumlen, GFP_KERNEL);
 524                                         if (!sumptr)
 525                                                 return -ENOMEM;
 526                                         memcpy(sumptr + sumlen - buf_len, buf + buf_size - buf_len, buf_len);
 527                                 }
 528                                 if (buf_len < sumlen) {
 529                                         /* Need to read more so that the entire summary node is present */
 530                                         err = jffs2_fill_scan_buf(c, sumptr,
 531                                                                   jeb->offset + c->sector_size - sumlen,
 532                                                                   sumlen - buf_len);
 533                                         if (err) {
 534                                                 if (sumlen > buf_size)
 535                                                         kfree(sumptr);
 536                                                 return err;
 537                                         }
 538                                 }
 539                         }
 540
 541                 }
 542
 543                 if (sumptr) {
 544                         err = jffs2_sum_scan_sumnode(c, jeb, sumptr, sumlen, &pseudo_random);
 545
 546                         if (buf_size && sumlen > buf_size)
 547                                 kfree(sumptr);
 548                         /* If it returns with a real error, bail.
 549                            If it returns positive, that's a block classification
 550                            (i.e. BLK_STATE_xxx) so return that too.
 551                            If it returns zero, fall through to full scan. */
 552                         if (err)
 553                                 return err;
 554                 }
 555         }
 556
 557 full_scan:
 558         buf_ofs = jeb->offset;
 559
 560         if (!buf_size) {
 561                 /* This is the XIP case -- we're reading _directly_ from the flash chip */
 562                 buf_len = c->sector_size;
 563         } else {
 564                 buf_len = EMPTY_SCAN_SIZE(c->sector_size);
 565                 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
 566                 if (err)
 567                         return err;
 568         }
 569
 570         /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
 571         ofs = 0;
 572         max_ofs = EMPTY_SCAN_SIZE(c->sector_size);
 573         /* Scan only EMPTY_SCAN_SIZE of 0xFF before declaring it's empty */
 574         while(ofs < max_ofs && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
 575                 ofs += 4;
 576
 577         if (ofs == max_ofs) {
 578 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 579                 if (jffs2_cleanmarker_oob(c)) {
 580                         /* scan oob, take care of cleanmarker */
 581                         int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
 582                         jffs2_dbg(2, "jffs2_check_oob_empty returned %d\n",
 583                                   ret);
 584                         switch (ret) {
 585                         case 0:         return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
 586                         case 1:         return BLK_STATE_ALLDIRTY;
 587                         default:        return ret;
 588                         }
 589                 }
 590 #endif
 591                 jffs2_dbg(1, "Block at 0x%08x is empty (erased)\n",
 592                           jeb->offset);
 593                 if (c->cleanmarker_size == 0)
 594                         return BLK_STATE_CLEANMARKER;   /* don't bother with re-erase */
 595                 else
 596                         return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
 597         }
 598         if (ofs) {
 599                 jffs2_dbg(1, "Free space at %08x ends at %08x\n", jeb->offset,
 600                           jeb->offset + ofs);
 601                 if ((err = jffs2_prealloc_raw_node_refs(c, jeb, 1)))
 602                         return err;
 603                 if ((err = jffs2_scan_dirty_space(c, jeb, ofs)))
 604                         return err;
 605         }
 606
 607         /* Now ofs is a complete physical flash offset as it always was... */
 608         ofs += jeb->offset;
 609
 610         noise = 10;
 611
 612         dbg_summary("no summary found in jeb 0x%08x. Apply original scan.\n",jeb->offset);
 613
 614 scan_more:
 615         while(ofs < jeb->offset + c->sector_size) {
 616
 617                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 618
 619                 /* Make sure there are node refs available for use */
 620                 err = jffs2_prealloc_raw_node_refs(c, jeb, 2);
 621                 if (err)
 622                         return err;
 623
 624                 cond_resched();
 625
 626                 if (ofs & 3) {
 627                         pr_warn("Eep. ofs 0x%08x not word-aligned!\n", ofs);
 628                         ofs = PAD(ofs);
 629                         continue;
 630                 }
 631                 if (ofs == prevofs) {
 632                         pr_warn("ofs 0x%08x has already been seen. Skipping\n",
 633                                 ofs);
 634                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 635                                 return err;
 636                         ofs += 4;
 637                         continue;
 638                 }
 639                 prevofs = ofs;
 640
 641                 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
 642                         jffs2_dbg(1, "Fewer than %zd bytes left to end of block. (%x+%x<%x+%zx) Not reading\n",
 643                                   sizeof(struct jffs2_unknown_node),
 644                                   jeb->offset, c->sector_size, ofs,
 645                                   sizeof(*node));
 646                         if ((err = jffs2_scan_dirty_space(c, jeb, (jeb->offset + c->sector_size)-ofs)))
 647                                 return err;
 648                         break;
 649                 }
 650
 651                 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
 652                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 653                         jffs2_dbg(1, "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
 654                                   sizeof(struct jffs2_unknown_node),
 655                                   buf_len, ofs);
 656                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 657                         if (err)
 658                                 return err;
 659                         buf_ofs = ofs;
 660                 }
 661
 662                 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
 663
 664                 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
 665                         uint32_t inbuf_ofs;
 666                         uint32_t empty_start, scan_end;
 667
 668                         empty_start = ofs;
 669                         ofs += 4;
 670                         scan_end = min_t(uint32_t, EMPTY_SCAN_SIZE(c->sector_size)/8, buf_len);
 671
 672                         jffs2_dbg(1, "Found empty flash at 0x%08x\n", ofs);
 673                 more_empty:
 674                         inbuf_ofs = ofs - buf_ofs;
 675                         while (inbuf_ofs < scan_end) {
 676                                 if (unlikely(*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff)) {
 677                                         pr_warn("Empty flash at 0x%08x ends at 0x%08x\n",
 678                                                 empty_start, ofs);
 679                                         if ((err = jffs2_scan_dirty_space(c, jeb, ofs-empty_start)))
 680                                                 return err;
 681                                         goto scan_more;
 682                                 }
 683
 684                                 inbuf_ofs+=4;
 685                                 ofs += 4;
 686                         }
 687                         /* Ran off end. */
 688                         jffs2_dbg(1, "Empty flash to end of buffer at 0x%08x\n",
 689                                   ofs);
 690
 691                         /* If we're only checking the beginning of a block with a cleanmarker,
 692                            bail now */
 693                         if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&
 694                             c->cleanmarker_size && !jeb->dirty_size && !ref_next(jeb->first_node)) {
 695                                 jffs2_dbg(1, "%d bytes at start of block seems clean... assuming all clean\n",
 696                                           EMPTY_SCAN_SIZE(c->sector_size));
 697                                 return BLK_STATE_CLEANMARKER;
 698                         }
 699                         if (!buf_size && (scan_end != buf_len)) {/* XIP/point case */
 700                                 scan_end = buf_len;
 701                                 goto more_empty;
 702                         }
 703
 704                         /* See how much more there is to read in this eraseblock... */
 705                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 706                         if (!buf_len) {
 707                                 /* No more to read. Break out of main loop without marking
 708                                    this range of empty space as dirty (because it's not) */
 709                                 jffs2_dbg(1, "Empty flash at %08x runs to end of block. Treating as free_space\n",
 710                                           empty_start);
 711                                 break;
 712                         }
 713                         /* point never reaches here */
 714                         scan_end = buf_len;
 715                         jffs2_dbg(1, "Reading another 0x%x at 0x%08x\n",
 716                                   buf_len, ofs);
 717                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 718                         if (err)
 719                                 return err;
 720                         buf_ofs = ofs;
 721                         goto more_empty;
 722                 }
 723
 724                 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
 725                         pr_warn("Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n",
 726                                 ofs);
 727                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 728                                 return err;
 729                         ofs += 4;
 730                         continue;
 731                 }
 732                 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
 733                         jffs2_dbg(1, "Dirty bitmask at 0x%08x\n", ofs);
 734                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 735                                 return err;
 736                         ofs += 4;
 737                         continue;
 738                 }
 739                 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
 740                         pr_warn("Old JFFS2 bitmask found at 0x%08x\n", ofs);
 741                         pr_warn("You cannot use older JFFS2 filesystems with newer kernels\n");
 742                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 743                                 return err;
 744                         ofs += 4;
 745                         continue;
 746                 }
 747                 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
 748                         /* OK. We're out of possibilities. Whinge and move on */
 749                         noisy_printk(&noise, "%s(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n",
 750                                      __func__,
 751                                      JFFS2_MAGIC_BITMASK, ofs,
 752                                      je16_to_cpu(node->magic));
 753                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 754                                 return err;
 755                         ofs += 4;
 756                         continue;
 757                 }
 758                 /* We seem to have a node of sorts. Check the CRC */
 759                 crcnode.magic = node->magic;
 760                 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
 761                 crcnode.totlen = node->totlen;
 762                 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
 763
 764                 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
 765                         noisy_printk(&noise, "%s(): Node at 0x%08x {0x%04x, 0x%04x, 0x%08x) has invalid CRC 0x%08x (calculated 0x%08x)\n",
 766                                      __func__,
 767                                      ofs, je16_to_cpu(node->magic),
 768                                      je16_to_cpu(node->nodetype),
 769                                      je32_to_cpu(node->totlen),
 770                                      je32_to_cpu(node->hdr_crc),
 771                                      hdr_crc);
 772                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 773                                 return err;
 774                         ofs += 4;
 775                         continue;
 776                 }
 777
 778                 if (ofs + je32_to_cpu(node->totlen) > jeb->offset + c->sector_size) {
 779                         /* Eep. Node goes over the end of the erase block. */
 780                         pr_warn("Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
 781                                 ofs, je32_to_cpu(node->totlen));
 782                         pr_warn("Perhaps the file system was created with the wrong erase size?\n");
 783                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
 784                                 return err;
 785                         ofs += 4;
 786                         continue;
 787                 }
 788
 789                 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
 790                         /* Wheee. This is an obsoleted node */
 791                         jffs2_dbg(2, "Node at 0x%08x is obsolete. Skipping\n",
 792                                   ofs);
 793                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 794                                 return err;
 795                         ofs += PAD(je32_to_cpu(node->totlen));
 796                         continue;
 797                 }
 798
 799                 switch(je16_to_cpu(node->nodetype)) {
 800                 case JFFS2_NODETYPE_INODE:
 801                         if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
 802                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 803                                 jffs2_dbg(1, "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
 804                                           sizeof(struct jffs2_raw_inode),
 805                                           buf_len, ofs);
 806                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 807                                 if (err)
 808                                         return err;
 809                                 buf_ofs = ofs;
 810                                 node = (void *)buf;
 811                         }
 812                         err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs, s);
 813                         if (err) return err;
 814                         ofs += PAD(je32_to_cpu(node->totlen));
 815                         break;
 816
 817                 case JFFS2_NODETYPE_DIRENT:
 818                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 819                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 820                                 jffs2_dbg(1, "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
 821                                           je32_to_cpu(node->totlen), buf_len,
 822                                           ofs);
 823                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 824                                 if (err)
 825                                         return err;
 826                                 buf_ofs = ofs;
 827                                 node = (void *)buf;
 828                         }
 829                         err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs, s);
 830                         if (err) return err;
 831                         ofs += PAD(je32_to_cpu(node->totlen));
 832                         break;
 833
 834 #ifdef CONFIG_JFFS2_FS_XATTR
 835                 case JFFS2_NODETYPE_XATTR:
 836                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 837                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 838                                 jffs2_dbg(1, "Fewer than %d bytes (xattr node) left to end of buf. Reading 0x%x at 0x%08x\n",
 839                                           je32_to_cpu(node->totlen), buf_len,
 840                                           ofs);
 841                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 842                                 if (err)
 843                                         return err;
 844                                 buf_ofs = ofs;
 845                                 node = (void *)buf;
 846                         }
 847                         err = jffs2_scan_xattr_node(c, jeb, (void *)node, ofs, s);
 848                         if (err)
 849                                 return err;
 850                         ofs += PAD(je32_to_cpu(node->totlen));
 851                         break;
 852                 case JFFS2_NODETYPE_XREF:
 853                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
 854                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
 855                                 jffs2_dbg(1, "Fewer than %d bytes (xref node) left to end of buf. Reading 0x%x at 0x%08x\n",
 856                                           je32_to_cpu(node->totlen), buf_len,
 857                                           ofs);
 858                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
 859                                 if (err)
 860                                         return err;
 861                                 buf_ofs = ofs;
 862                                 node = (void *)buf;
 863                         }
 864                         err = jffs2_scan_xref_node(c, jeb, (void *)node, ofs, s);
 865                         if (err)
 866                                 return err;
 867                         ofs += PAD(je32_to_cpu(node->totlen));
 868                         break;
 869 #endif  /* CONFIG_JFFS2_FS_XATTR */
 870
 871                 case JFFS2_NODETYPE_CLEANMARKER:
 872                         jffs2_dbg(1, "CLEANMARKER node found at 0x%08x\n", ofs);
 873                         if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
 874                                 pr_notice("CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n",
 875                                           ofs, je32_to_cpu(node->totlen),
 876                                           c->cleanmarker_size);
 877                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
 878                                         return err;
 879                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 880                         } else if (jeb->first_node) {
 881                                 pr_notice("CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n",
 882                                           ofs, jeb->offset);
 883                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
 884                                         return err;
 885                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
 886                         } else {
 887                                 jffs2_link_node_ref(c, jeb, ofs | REF_NORMAL, c->cleanmarker_size, NULL);
 888
 889                                 ofs += PAD(c->cleanmarker_size);
 890                         }
 891                         break;
 892
 893                 case JFFS2_NODETYPE_PADDING:
 894                         if (jffs2_sum_active())
 895                                 jffs2_sum_add_padding_mem(s, je32_to_cpu(node->totlen));
 896                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 897                                 return err;
 898                         ofs += PAD(je32_to_cpu(node->totlen));
 899                         break;
 900
 901                 default:
 902                         switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
 903                         case JFFS2_FEATURE_ROCOMPAT:
 904                                 pr_notice("Read-only compatible feature node (0x%04x) found at offset 0x%08x\n",
 905                                           je16_to_cpu(node->nodetype), ofs);
 906                                 c->flags |= JFFS2_SB_FLAG_RO;
 907                                 if (!(jffs2_is_readonly(c)))
 908                                         return -EROFS;
 909                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 910                                         return err;
 911                                 ofs += PAD(je32_to_cpu(node->totlen));
 912                                 break;
 913
 914                         case JFFS2_FEATURE_INCOMPAT:
 915                                 pr_notice("Incompatible feature node (0x%04x) found at offset 0x%08x\n",
 916                                           je16_to_cpu(node->nodetype), ofs);
 917                                 return -EINVAL;
 918
 919                         case JFFS2_FEATURE_RWCOMPAT_DELETE:
 920                                 jffs2_dbg(1, "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n",
 921                                           je16_to_cpu(node->nodetype), ofs);
 922                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
 923                                         return err;
 924                                 ofs += PAD(je32_to_cpu(node->totlen));
 925                                 break;
 926
 927                         case JFFS2_FEATURE_RWCOMPAT_COPY: {
 928                                 jffs2_dbg(1, "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n",
 929                                           je16_to_cpu(node->nodetype), ofs);
 930
 931                                 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(node->totlen)), NULL);
 932
 933                                 /* We can't summarise nodes we don't grok */
 934                                 jffs2_sum_disable_collecting(s);
 935                                 ofs += PAD(je32_to_cpu(node->totlen));
 936                                 break;
 937                                 }
 938                         }
 939                 }
 940         }
 941
 942         if (jffs2_sum_active()) {
 943                 if (PAD(s->sum_size + JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size) {
 944                         dbg_summary("There is not enough space for "
 945                                 "summary information, disabling for this jeb!\n");
 946                         jffs2_sum_disable_collecting(s);
 947                 }
 948         }
 949
 950         jffs2_dbg(1, "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x, wasted 0x%08x\n",
 951                   jeb->offset, jeb->free_size, jeb->dirty_size,
 952                   jeb->unchecked_size, jeb->used_size, jeb->wasted_size);
 953
 954         /* mark_node_obsolete can add to wasted !! */
 955         if (jeb->wasted_size) {
 956                 jeb->dirty_size += jeb->wasted_size;
 957                 c->dirty_size += jeb->wasted_size;
 958                 c->wasted_size -= jeb->wasted_size;
 959                 jeb->wasted_size = 0;
 960         }
 961
 962         return jffs2_scan_classify_jeb(c, jeb);
 963 }
 964
 965 struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
 966 {
 967         struct jffs2_inode_cache *ic;
 968
 969         ic = jffs2_get_ino_cache(c, ino);
 970         if (ic)
 971                 return ic;
 972
 973         if (ino > c->highest_ino)
 974                 c->highest_ino = ino;
 975
 976         ic = jffs2_alloc_inode_cache();
 977         if (!ic) {
 978                 pr_notice("%s(): allocation of inode cache failed\n", __func__);
 979                 return NULL;
 980         }
 981         memset(ic, 0, sizeof(*ic));
 982
 983         ic->ino = ino;
 984         ic->nodes = (void *)ic;
 985         jffs2_add_ino_cache(c, ic);
 986         if (ino == 1)
 987                 ic->pino_nlink = 1;
 988         return ic;
 989 }
 990
 991 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 992                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s)
 993 {
 994         struct jffs2_inode_cache *ic;
 995         uint32_t crc, ino = je32_to_cpu(ri->ino);
 996
 997         jffs2_dbg(1, "%s(): Node at 0x%08x\n", __func__, ofs);
 998
 999         /* We do very little here now. Just check the ino# to which we should attribute
1000            this node; we can do all the CRC checking etc. later. There's a tradeoff here --
1001            we used to scan the flash once only, reading everything we want from it into
1002            memory, then building all our in-core data structures and freeing the extra
1003            information. Now we allow the first part of the mount to complete a lot quicker,
1004            but we have to go _back_ to the flash in order to finish the CRC checking, etc.
1005            Which means that the _full_ amount of time to get to proper write mode with GC
1006            operational may actually be _longer_ than before. Sucks to be me. */
1007
1008         /* Check the node CRC in any case. */
1009         crc = crc32(0, ri, sizeof(*ri)-8);
1010         if (crc != je32_to_cpu(ri->node_crc)) {
1011                 pr_notice("%s(): CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1012                           __func__, ofs, je32_to_cpu(ri->node_crc), crc);
1013                 /*
1014                  * We believe totlen because the CRC on the node
1015                  * _header_ was OK, just the node itself failed.
1016                  */
1017                 return jffs2_scan_dirty_space(c, jeb,
1018                                               PAD(je32_to_cpu(ri->totlen)));
1019         }
1020
1021         ic = jffs2_get_ino_cache(c, ino);
1022         if (!ic) {
1023                 ic = jffs2_scan_make_ino_cache(c, ino);
1024                 if (!ic)
1025                         return -ENOMEM;
1026         }
1027
1028         /* Wheee. It worked */
1029         jffs2_link_node_ref(c, jeb, ofs | REF_UNCHECKED, PAD(je32_to_cpu(ri->totlen)), ic);
1030
1031         jffs2_dbg(1, "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
1032                   je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
1033                   je32_to_cpu(ri->offset),
1034                   je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize));
1035
1036         pseudo_random += je32_to_cpu(ri->version);
1037
1038         if (jffs2_sum_active()) {
1039                 jffs2_sum_add_inode_mem(s, ri, ofs - jeb->offset);
1040         }
1041
1042         return 0;
1043 }
1044
1045 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
1046                                   struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s)
1047 {
1048         struct jffs2_full_dirent *fd;
1049         struct jffs2_inode_cache *ic;
1050         uint32_t checkedlen;
1051         uint32_t crc;
1052         int err;
1053
1054         jffs2_dbg(1, "%s(): Node at 0x%08x\n", __func__, ofs);
1055
1056         /* We don't get here unless the node is still valid, so we don't have to
1057            mask in the ACCURATE bit any more. */
1058         crc = crc32(0, rd, sizeof(*rd)-8);
1059
1060         if (crc != je32_to_cpu(rd->node_crc)) {
1061                 pr_notice("%s(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1062                           __func__, ofs, je32_to_cpu(rd->node_crc), crc);
1063                 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
1064                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1065                         return err;
1066                 return 0;
1067         }
1068
1069         pseudo_random += je32_to_cpu(rd->version);
1070
1071         /* Should never happen. Did. (OLPC trac #4184)*/
1072         checkedlen = strnlen(rd->name, rd->nsize);
1073         if (checkedlen < rd->nsize) {
1074                 pr_err("Dirent at %08x has zeroes in name. Truncating to %d chars\n",
1075                        ofs, checkedlen);
1076         }
1077         fd = jffs2_alloc_full_dirent(checkedlen+1);
1078         if (!fd) {
1079                 return -ENOMEM;
1080         }
1081         memcpy(&fd->name, rd->name, checkedlen);
1082         fd->name[checkedlen] = 0;
1083
1084         crc = crc32(0, fd->name, checkedlen);
1085         if (crc != je32_to_cpu(rd->name_crc)) {
1086                 pr_notice("%s(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1087                           __func__, ofs, je32_to_cpu(rd->name_crc), crc);
1088                 jffs2_dbg(1, "Name for which CRC failed is (now) '%s', ino #%d\n",
1089                           fd->name, je32_to_cpu(rd->ino));
1090                 jffs2_free_full_dirent(fd);
1091                 /* FIXME: Why do we believe totlen? */
1092                 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
1093                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1094                         return err;
1095                 return 0;
1096         }
1097         ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
1098         if (!ic) {
1099                 jffs2_free_full_dirent(fd);
1100                 return -ENOMEM;
1101         }
1102
1103         fd->raw = jffs2_link_node_ref(c, jeb, ofs | dirent_node_state(rd),
1104                                       PAD(je32_to_cpu(rd->totlen)), ic);
1105
1106         fd->next = NULL;
1107         fd->version = je32_to_cpu(rd->version);
1108         fd->ino = je32_to_cpu(rd->ino);
1109         fd->nhash = full_name_hash(NULL, fd->name, checkedlen);
1110         fd->type = rd->type;
1111         jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
1112
1113         if (jffs2_sum_active()) {
1114                 jffs2_sum_add_dirent_mem(s, rd, ofs - jeb->offset);
1115         }
1116
1117         return 0;
1118 }
1119
1120 static int count_list(struct list_head *l)
1121 {
1122         uint32_t count = 0;
1123         struct list_head *tmp;
1124
1125         list_for_each(tmp, l) {
1126                 count++;
1127         }
1128         return count;
1129 }
1130
1131 /* Note: This breaks if list_empty(head). I don't care. You
1132    might, if you copy this code and use it elsewhere :) */
1133 static void rotate_list(struct list_head *head, uint32_t count)
1134 {
1135         struct list_head *n = head->next;
1136
1137         list_del(head);
1138         while(count--) {
1139                 n = n->next;
1140         }
1141         list_add(head, n);
1142 }
1143
1144 void jffs2_rotate_lists(struct jffs2_sb_info *c)
1145 {
1146         uint32_t x;
1147         uint32_t rotateby;
1148
1149         x = count_list(&c->clean_list);
1150         if (x) {
1151                 rotateby = pseudo_random % x;
1152                 rotate_list((&c->clean_list), rotateby);
1153         }
1154
1155         x = count_list(&c->very_dirty_list);
1156         if (x) {
1157                 rotateby = pseudo_random % x;
1158                 rotate_list((&c->very_dirty_list), rotateby);
1159         }
1160
1161         x = count_list(&c->dirty_list);
1162         if (x) {
1163                 rotateby = pseudo_random % x;
1164                 rotate_list((&c->dirty_list), rotateby);
1165         }
1166
1167         x = count_list(&c->erasable_list);
1168         if (x) {
1169                 rotateby = pseudo_random % x;
1170                 rotate_list((&c->erasable_list), rotateby);
1171         }
1172
1173         if (c->nr_erasing_blocks) {
1174                 rotateby = pseudo_random % c->nr_erasing_blocks;
1175                 rotate_list((&c->erase_pending_list), rotateby);
1176         }
1177
1178         if (c->nr_free_blocks) {
1179                 rotateby = pseudo_random % c->nr_free_blocks;
1180                 rotate_list((&c->free_list), rotateby);
1181         }
1182 }