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Linux/fs/jffs2/scan.c

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

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