[JFFS2] Introduce jffs2_scan_dirty_space() function.
[linux-2.6.git] / fs / jffs2 / scan.c
1 /*
2  * JFFS2 -- Journalling Flash File System, Version 2.
3  *
4  * Copyright (C) 2001-2003 Red Hat, Inc.
5  *
6  * Created by David Woodhouse <dwmw2@infradead.org>
7  *
8  * For licensing information, see the file 'LICENCE' in this directory.
9  *
10  * $Id: scan.c,v 1.125 2005/09/30 13:59:13 dedekind Exp $
11  *
12  */
13 #include <linux/kernel.h>
14 #include <linux/sched.h>
15 #include <linux/slab.h>
16 #include <linux/mtd/mtd.h>
17 #include <linux/pagemap.h>
18 #include <linux/crc32.h>
19 #include <linux/compiler.h>
20 #include "nodelist.h"
21 #include "summary.h"
22 #include "debug.h"
23
24 #define DEFAULT_EMPTY_SCAN_SIZE 1024
25
26 #define noisy_printk(noise, args...) do { \
27         if (*(noise)) { \
28                 printk(KERN_NOTICE args); \
29                  (*(noise))--; \
30                  if (!(*(noise))) { \
31                          printk(KERN_NOTICE "Further such events for this erase block will not be printed\n"); \
32                  } \
33         } \
34 } while(0)
35
36 static uint32_t pseudo_random;
37
38 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
39                                   unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s);
40
41 /* These helper functions _must_ increase ofs and also do the dirty/used space accounting.
42  * Returning an error will abort the mount - bad checksums etc. should just mark the space
43  * as dirty.
44  */
45 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
46                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s);
47 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
48                                  struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s);
49
50 static inline int min_free(struct jffs2_sb_info *c)
51 {
52         uint32_t min = 2 * sizeof(struct jffs2_raw_inode);
53 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
54         if (!jffs2_can_mark_obsolete(c) && min < c->wbuf_pagesize)
55                 return c->wbuf_pagesize;
56 #endif
57         return min;
58
59 }
60
61 static inline uint32_t EMPTY_SCAN_SIZE(uint32_t sector_size) {
62         if (sector_size < DEFAULT_EMPTY_SCAN_SIZE)
63                 return sector_size;
64         else
65                 return DEFAULT_EMPTY_SCAN_SIZE;
66 }
67
68 int jffs2_scan_medium(struct jffs2_sb_info *c)
69 {
70         int i, ret;
71         uint32_t empty_blocks = 0, bad_blocks = 0;
72         unsigned char *flashbuf = NULL;
73         uint32_t buf_size = 0;
74         struct jffs2_summary *s = NULL; /* summary info collected by the scan process */
75 #ifndef __ECOS
76         size_t pointlen;
77
78         if (c->mtd->point) {
79                 ret = c->mtd->point (c->mtd, 0, c->mtd->size, &pointlen, &flashbuf);
80                 if (!ret && pointlen < c->mtd->size) {
81                         /* Don't muck about if it won't let us point to the whole flash */
82                         D1(printk(KERN_DEBUG "MTD point returned len too short: 0x%zx\n", pointlen));
83                         c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
84                         flashbuf = NULL;
85                 }
86                 if (ret)
87                         D1(printk(KERN_DEBUG "MTD point failed %d\n", ret));
88         }
89 #endif
90         if (!flashbuf) {
91                 /* For NAND it's quicker to read a whole eraseblock at a time,
92                    apparently */
93                 if (jffs2_cleanmarker_oob(c))
94                         buf_size = c->sector_size;
95                 else
96                         buf_size = PAGE_SIZE;
97
98                 /* Respect kmalloc limitations */
99                 if (buf_size > 128*1024)
100                         buf_size = 128*1024;
101
102                 D1(printk(KERN_DEBUG "Allocating readbuf of %d bytes\n", buf_size));
103                 flashbuf = kmalloc(buf_size, GFP_KERNEL);
104                 if (!flashbuf)
105                         return -ENOMEM;
106         }
107
108         if (jffs2_sum_active()) {
109                 s = kmalloc(sizeof(struct jffs2_summary), GFP_KERNEL);
110                 if (!s) {
111                         JFFS2_WARNING("Can't allocate memory for summary\n");
112                         return -ENOMEM;
113                 }
114                 memset(s, 0, sizeof(struct jffs2_summary));
115         }
116
117         for (i=0; i<c->nr_blocks; i++) {
118                 struct jffs2_eraseblock *jeb = &c->blocks[i];
119
120                 /* reset summary info for next eraseblock scan */
121                 jffs2_sum_reset_collected(s);
122
123                 ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset),
124                                                 buf_size, s);
125
126                 if (ret < 0)
127                         goto out;
128
129                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
130
131                 /* Now decide which list to put it on */
132                 switch(ret) {
133                 case BLK_STATE_ALLFF:
134                         /*
135                          * Empty block.   Since we can't be sure it
136                          * was entirely erased, we just queue it for erase
137                          * again.  It will be marked as such when the erase
138                          * is complete.  Meanwhile we still count it as empty
139                          * for later checks.
140                          */
141                         empty_blocks++;
142                         list_add(&jeb->list, &c->erase_pending_list);
143                         c->nr_erasing_blocks++;
144                         break;
145
146                 case BLK_STATE_CLEANMARKER:
147                         /* Only a CLEANMARKER node is valid */
148                         if (!jeb->dirty_size) {
149                                 /* It's actually free */
150                                 list_add(&jeb->list, &c->free_list);
151                                 c->nr_free_blocks++;
152                         } else {
153                                 /* Dirt */
154                                 D1(printk(KERN_DEBUG "Adding all-dirty block at 0x%08x to erase_pending_list\n", jeb->offset));
155                                 list_add(&jeb->list, &c->erase_pending_list);
156                                 c->nr_erasing_blocks++;
157                         }
158                         break;
159
160                 case BLK_STATE_CLEAN:
161                         /* Full (or almost full) of clean data. Clean list */
162                         list_add(&jeb->list, &c->clean_list);
163                         break;
164
165                 case BLK_STATE_PARTDIRTY:
166                         /* Some data, but not full. Dirty list. */
167                         /* We want to remember the block with most free space
168                         and stick it in the 'nextblock' position to start writing to it. */
169                         if (jeb->free_size > min_free(c) &&
170                                         (!c->nextblock || c->nextblock->free_size < jeb->free_size)) {
171                                 /* Better candidate for the next writes to go to */
172                                 if (c->nextblock) {
173                                         c->nextblock->dirty_size += c->nextblock->free_size + c->nextblock->wasted_size;
174                                         c->dirty_size += c->nextblock->free_size + c->nextblock->wasted_size;
175                                         c->free_size -= c->nextblock->free_size;
176                                         c->wasted_size -= c->nextblock->wasted_size;
177                                         c->nextblock->free_size = c->nextblock->wasted_size = 0;
178                                         if (VERYDIRTY(c, c->nextblock->dirty_size)) {
179                                                 list_add(&c->nextblock->list, &c->very_dirty_list);
180                                         } else {
181                                                 list_add(&c->nextblock->list, &c->dirty_list);
182                                         }
183                                         /* deleting summary information of the old nextblock */
184                                         jffs2_sum_reset_collected(c->summary);
185                                 }
186                                 /* update collected summary infromation for the current nextblock */
187                                 jffs2_sum_move_collected(c, s);
188                                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): new nextblock = 0x%08x\n", jeb->offset));
189                                 c->nextblock = jeb;
190                         } else {
191                                 jeb->dirty_size += jeb->free_size + jeb->wasted_size;
192                                 c->dirty_size += jeb->free_size + jeb->wasted_size;
193                                 c->free_size -= jeb->free_size;
194                                 c->wasted_size -= jeb->wasted_size;
195                                 jeb->free_size = jeb->wasted_size = 0;
196                                 if (VERYDIRTY(c, jeb->dirty_size)) {
197                                         list_add(&jeb->list, &c->very_dirty_list);
198                                 } else {
199                                         list_add(&jeb->list, &c->dirty_list);
200                                 }
201                         }
202                         break;
203
204                 case BLK_STATE_ALLDIRTY:
205                         /* Nothing valid - not even a clean marker. Needs erasing. */
206                         /* For now we just put it on the erasing list. We'll start the erases later */
207                         D1(printk(KERN_NOTICE "JFFS2: Erase block at 0x%08x is not formatted. It will be erased\n", jeb->offset));
208                         list_add(&jeb->list, &c->erase_pending_list);
209                         c->nr_erasing_blocks++;
210                         break;
211
212                 case BLK_STATE_BADBLOCK:
213                         D1(printk(KERN_NOTICE "JFFS2: Block at 0x%08x is bad\n", jeb->offset));
214                         list_add(&jeb->list, &c->bad_list);
215                         c->bad_size += c->sector_size;
216                         c->free_size -= c->sector_size;
217                         bad_blocks++;
218                         break;
219                 default:
220                         printk(KERN_WARNING "jffs2_scan_medium(): unknown block state\n");
221                         BUG();
222                 }
223         }
224
225         /* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
226         if (c->nextblock && (c->nextblock->dirty_size)) {
227                 c->nextblock->wasted_size += c->nextblock->dirty_size;
228                 c->wasted_size += c->nextblock->dirty_size;
229                 c->dirty_size -= c->nextblock->dirty_size;
230                 c->nextblock->dirty_size = 0;
231         }
232 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
233         if (!jffs2_can_mark_obsolete(c) && c->wbuf_pagesize && c->nextblock && (c->nextblock->free_size % c->wbuf_pagesize)) {
234                 /* If we're going to start writing into a block which already
235                    contains data, and the end of the data isn't page-aligned,
236                    skip a little and align it. */
237
238                 uint32_t skip = c->nextblock->free_size % c->wbuf_pagesize;
239
240                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): Skipping %d bytes in nextblock to ensure page alignment\n",
241                           skip));
242                 c->nextblock->wasted_size += skip;
243                 c->wasted_size += skip;
244
245                 c->nextblock->free_size -= skip;
246                 c->free_size -= skip;
247         }
248 #endif
249         if (c->nr_erasing_blocks) {
250                 if ( !c->used_size && ((c->nr_free_blocks+empty_blocks+bad_blocks)!= c->nr_blocks || bad_blocks == c->nr_blocks) ) {
251                         printk(KERN_NOTICE "Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
252                         printk(KERN_NOTICE "empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",empty_blocks,bad_blocks,c->nr_blocks);
253                         ret = -EIO;
254                         goto out;
255                 }
256                 jffs2_erase_pending_trigger(c);
257         }
258         ret = 0;
259  out:
260         if (buf_size)
261                 kfree(flashbuf);
262 #ifndef __ECOS
263         else
264                 c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
265 #endif
266         if (s)
267                 kfree(s);
268
269         return ret;
270 }
271
272 int jffs2_fill_scan_buf (struct jffs2_sb_info *c, void *buf,
273                                 uint32_t ofs, uint32_t len)
274 {
275         int ret;
276         size_t retlen;
277
278         ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
279         if (ret) {
280                 D1(printk(KERN_WARNING "mtd->read(0x%x bytes from 0x%x) returned %d\n", len, ofs, ret));
281                 return ret;
282         }
283         if (retlen < len) {
284                 D1(printk(KERN_WARNING "Read at 0x%x gave only 0x%zx bytes\n", ofs, retlen));
285                 return -EIO;
286         }
287         return 0;
288 }
289
290 int jffs2_scan_classify_jeb(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
291 {
292         if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size
293                 && (!jeb->first_node || !jeb->first_node->next_phys) )
294                 return BLK_STATE_CLEANMARKER;
295
296         /* move blocks with max 4 byte dirty space to cleanlist */
297         else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
298                 c->dirty_size -= jeb->dirty_size;
299                 c->wasted_size += jeb->dirty_size;
300                 jeb->wasted_size += jeb->dirty_size;
301                 jeb->dirty_size = 0;
302                 return BLK_STATE_CLEAN;
303         } else if (jeb->used_size || jeb->unchecked_size)
304                 return BLK_STATE_PARTDIRTY;
305         else
306                 return BLK_STATE_ALLDIRTY;
307 }
308
309 #ifdef CONFIG_JFFS2_FS_XATTR
310 static int jffs2_scan_xattr_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
311                                  struct jffs2_raw_xattr *rx, uint32_t ofs,
312                                  struct jffs2_summary *s)
313 {
314         struct jffs2_xattr_datum *xd;
315         struct jffs2_raw_node_ref *raw;
316         uint32_t totlen, crc;
317         int err;
318
319         crc = crc32(0, rx, sizeof(struct jffs2_raw_xattr) - 4);
320         if (crc != je32_to_cpu(rx->node_crc)) {
321                 if (je32_to_cpu(rx->node_crc) != 0xffffffff)
322                         JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
323                                       ofs, je32_to_cpu(rx->node_crc), crc);
324                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
325                         return err;
326                 return 0;
327         }
328
329         totlen = PAD(sizeof(*rx) + rx->name_len + 1 + je16_to_cpu(rx->value_len));
330         if (totlen != je32_to_cpu(rx->totlen)) {
331                 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%u\n",
332                               ofs, je32_to_cpu(rx->totlen), totlen);
333                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
334                         return err;
335                 return 0;
336         }
337
338         raw =  jffs2_alloc_raw_node_ref();
339         if (!raw)
340                 return -ENOMEM;
341
342         xd = jffs2_setup_xattr_datum(c, je32_to_cpu(rx->xid), je32_to_cpu(rx->version));
343         if (IS_ERR(xd)) {
344                 jffs2_free_raw_node_ref(raw);
345                 if (PTR_ERR(xd) == -EEXIST) {
346                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rx->totlen)))))
347                                 return err;
348                         return 0;
349                 }
350                 return PTR_ERR(xd);
351         }
352         xd->xprefix = rx->xprefix;
353         xd->name_len = rx->name_len;
354         xd->value_len = je16_to_cpu(rx->value_len);
355         xd->data_crc = je32_to_cpu(rx->data_crc);
356         xd->node = raw;
357
358         raw->flash_offset = ofs | REF_PRISTINE;
359         raw->next_in_ino = (void *)xd;
360
361         jffs2_link_node_ref(c, jeb, raw, totlen);
362
363         if (jffs2_sum_active())
364                 jffs2_sum_add_xattr_mem(s, rx, ofs - jeb->offset);
365         dbg_xattr("scaning xdatum at %#08x (xid=%u, version=%u)\n",
366                   ofs, xd->xid, xd->version);
367         return 0;
368 }
369
370 static int jffs2_scan_xref_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
371                                 struct jffs2_raw_xref *rr, uint32_t ofs,
372                                 struct jffs2_summary *s)
373 {
374         struct jffs2_xattr_ref *ref;
375         struct jffs2_raw_node_ref *raw;
376         uint32_t crc;
377         int err;
378
379         crc = crc32(0, rr, sizeof(*rr) - 4);
380         if (crc != je32_to_cpu(rr->node_crc)) {
381                 if (je32_to_cpu(rr->node_crc) != 0xffffffff)
382                         JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
383                                       ofs, je32_to_cpu(rr->node_crc), crc);
384                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rr->totlen)))))
385                         return err;
386                 return 0;
387         }
388
389         if (PAD(sizeof(struct jffs2_raw_xref)) != je32_to_cpu(rr->totlen)) {
390                 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%u\n",
391                               ofs, je32_to_cpu(rr->totlen),
392                               PAD(sizeof(struct jffs2_raw_xref)));
393                 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rr->totlen))))
394                         return err;
395                 return 0;
396         }
397
398         ref = jffs2_alloc_xattr_ref();
399         if (!ref)
400                 return -ENOMEM;
401
402         raw =  jffs2_alloc_raw_node_ref();
403         if (!raw) {
404                 jffs2_free_xattr_ref(ref);
405                 return -ENOMEM;
406         }
407
408         /* BEFORE jffs2_build_xattr_subsystem() called, 
409          * ref->xid is used to store 32bit xid, xd is not used
410          * ref->ino is used to store 32bit inode-number, ic is not used
411          * Thoes variables are declared as union, thus using those
412          * are exclusive. In a similar way, ref->next is temporarily
413          * used to chain all xattr_ref object. It's re-chained to
414          * jffs2_inode_cache in jffs2_build_xattr_subsystem() correctly.
415          */
416         ref->node = raw;
417         ref->ino = je32_to_cpu(rr->ino);
418         ref->xid = je32_to_cpu(rr->xid);
419         ref->next = c->xref_temp;
420         c->xref_temp = ref;
421
422         raw->flash_offset = ofs | REF_PRISTINE;
423         raw->next_in_ino = (void *)ref;
424
425         jffs2_link_node_ref(c, jeb, raw, PAD(je32_to_cpu(rr->totlen)));
426
427         if (jffs2_sum_active())
428                 jffs2_sum_add_xref_mem(s, rr, ofs - jeb->offset);
429         dbg_xattr("scan xref at %#08x (xid=%u, ino=%u)\n",
430                   ofs, ref->xid, ref->ino);
431         return 0;
432 }
433 #endif
434
435 /* Called with 'buf_size == 0' if buf is in fact a pointer _directly_ into
436    the flash, XIP-style */
437 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
438                                   unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) {
439         struct jffs2_unknown_node *node;
440         struct jffs2_unknown_node crcnode;
441         uint32_t ofs, prevofs;
442         uint32_t hdr_crc, buf_ofs, buf_len;
443         int err;
444         int noise = 0;
445
446
447 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
448         int cleanmarkerfound = 0;
449 #endif
450
451         ofs = jeb->offset;
452         prevofs = jeb->offset - 1;
453
454         D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs));
455
456 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
457         if (jffs2_cleanmarker_oob(c)) {
458                 int ret = jffs2_check_nand_cleanmarker(c, jeb);
459                 D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n",ret));
460                 /* Even if it's not found, we still scan to see
461                    if the block is empty. We use this information
462                    to decide whether to erase it or not. */
463                 switch (ret) {
464                 case 0:         cleanmarkerfound = 1; break;
465                 case 1:         break;
466                 case 2:         return BLK_STATE_BADBLOCK;
467                 case 3:         return BLK_STATE_ALLDIRTY; /* Block has failed to erase min. once */
468                 default:        return ret;
469                 }
470         }
471 #endif
472
473         if (jffs2_sum_active()) {
474                 struct jffs2_sum_marker *sm;
475                 void *sumptr = NULL;
476                 uint32_t sumlen;
477               
478                 if (!buf_size) {
479                         /* XIP case. Just look, point at the summary if it's there */
480                         sm = (void *)buf + jeb->offset - sizeof(*sm);
481                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
482                                 sumptr = buf + je32_to_cpu(sm->offset);
483                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
484                         }
485                 } else {
486                         /* If NAND flash, read a whole page of it. Else just the end */
487                         if (c->wbuf_pagesize)
488                                 buf_len = c->wbuf_pagesize;
489                         else
490                                 buf_len = sizeof(*sm);
491
492                         /* Read as much as we want into the _end_ of the preallocated buffer */
493                         err = jffs2_fill_scan_buf(c, buf + buf_size - buf_len, 
494                                                   jeb->offset + c->sector_size - buf_len,
495                                                   buf_len);                             
496                         if (err)
497                                 return err;
498
499                         sm = (void *)buf + buf_size - sizeof(*sm);
500                         if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
501                                 sumlen = c->sector_size - je32_to_cpu(sm->offset);
502                                 sumptr = buf + buf_size - sumlen;
503
504                                 /* Now, make sure the summary itself is available */
505                                 if (sumlen > buf_size) {
506                                         /* Need to kmalloc for this. */
507                                         sumptr = kmalloc(sumlen, GFP_KERNEL);
508                                         if (!sumptr)
509                                                 return -ENOMEM;
510                                         memcpy(sumptr + sumlen - buf_len, buf + buf_size - buf_len, buf_len);
511                                 }
512                                 if (buf_len < sumlen) {
513                                         /* Need to read more so that the entire summary node is present */
514                                         err = jffs2_fill_scan_buf(c, sumptr, 
515                                                                   jeb->offset + c->sector_size - sumlen,
516                                                                   sumlen - buf_len);                            
517                                         if (err)
518                                                 return err;
519                                 }
520                         }
521
522                 }
523
524                 if (sumptr) {
525                         err = jffs2_sum_scan_sumnode(c, jeb, sumptr, sumlen, &pseudo_random);
526
527                         if (buf_size && sumlen > buf_size)
528                                 kfree(sumptr);
529                         /* If it returns with a real error, bail. 
530                            If it returns positive, that's a block classification
531                            (i.e. BLK_STATE_xxx) so return that too.
532                            If it returns zero, fall through to full scan. */
533                         if (err)
534                                 return err;
535                 }
536         }
537
538         buf_ofs = jeb->offset;
539
540         if (!buf_size) {
541                 /* This is the XIP case -- we're reading _directly_ from the flash chip */
542                 buf_len = c->sector_size;
543         } else {
544                 buf_len = EMPTY_SCAN_SIZE(c->sector_size);
545                 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
546                 if (err)
547                         return err;
548         }
549
550         /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
551         ofs = 0;
552
553         /* Scan only 4KiB of 0xFF before declaring it's empty */
554         while(ofs < EMPTY_SCAN_SIZE(c->sector_size) && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
555                 ofs += 4;
556
557         if (ofs == EMPTY_SCAN_SIZE(c->sector_size)) {
558 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
559                 if (jffs2_cleanmarker_oob(c)) {
560                         /* scan oob, take care of cleanmarker */
561                         int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
562                         D2(printk(KERN_NOTICE "jffs2_check_oob_empty returned %d\n",ret));
563                         switch (ret) {
564                         case 0:         return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
565                         case 1:         return BLK_STATE_ALLDIRTY;
566                         default:        return ret;
567                         }
568                 }
569 #endif
570                 D1(printk(KERN_DEBUG "Block at 0x%08x is empty (erased)\n", jeb->offset));
571                 if (c->cleanmarker_size == 0)
572                         return BLK_STATE_CLEANMARKER;   /* don't bother with re-erase */
573                 else
574                         return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
575         }
576         if (ofs) {
577                 D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset,
578                           jeb->offset + ofs));
579                 if ((err = jffs2_scan_dirty_space(c, jeb, ofs)))
580                         return err;
581         }
582
583         /* Now ofs is a complete physical flash offset as it always was... */
584         ofs += jeb->offset;
585
586         noise = 10;
587
588         dbg_summary("no summary found in jeb 0x%08x. Apply original scan.\n",jeb->offset);
589
590 scan_more:
591         while(ofs < jeb->offset + c->sector_size) {
592
593                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
594
595                 cond_resched();
596
597                 if (ofs & 3) {
598                         printk(KERN_WARNING "Eep. ofs 0x%08x not word-aligned!\n", ofs);
599                         ofs = PAD(ofs);
600                         continue;
601                 }
602                 if (ofs == prevofs) {
603                         printk(KERN_WARNING "ofs 0x%08x has already been seen. Skipping\n", ofs);
604                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
605                                 return err;
606                         ofs += 4;
607                         continue;
608                 }
609                 prevofs = ofs;
610
611                 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
612                         D1(printk(KERN_DEBUG "Fewer than %zd bytes left to end of block. (%x+%x<%x+%zx) Not reading\n", sizeof(struct jffs2_unknown_node),
613                                   jeb->offset, c->sector_size, ofs, sizeof(*node)));
614                         if ((err = jffs2_scan_dirty_space(c, jeb, (jeb->offset + c->sector_size)-ofs)))
615                                 return err;
616                         break;
617                 }
618
619                 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
620                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
621                         D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
622                                   sizeof(struct jffs2_unknown_node), buf_len, ofs));
623                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
624                         if (err)
625                                 return err;
626                         buf_ofs = ofs;
627                 }
628
629                 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
630
631                 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
632                         uint32_t inbuf_ofs;
633                         uint32_t empty_start;
634
635                         empty_start = ofs;
636                         ofs += 4;
637
638                         D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs));
639                 more_empty:
640                         inbuf_ofs = ofs - buf_ofs;
641                         while (inbuf_ofs < buf_len) {
642                                 if (*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff) {
643                                         printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n",
644                                                empty_start, ofs);
645                                         if ((err = jffs2_scan_dirty_space(c, jeb, ofs-empty_start)))
646                                                 return err;
647                                         goto scan_more;
648                                 }
649
650                                 inbuf_ofs+=4;
651                                 ofs += 4;
652                         }
653                         /* Ran off end. */
654                         D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs));
655
656                         /* If we're only checking the beginning of a block with a cleanmarker,
657                            bail now */
658                         if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&
659                             c->cleanmarker_size && !jeb->dirty_size && !jeb->first_node->next_phys) {
660                                 D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE(c->sector_size)));
661                                 return BLK_STATE_CLEANMARKER;
662                         }
663
664                         /* See how much more there is to read in this eraseblock... */
665                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
666                         if (!buf_len) {
667                                 /* No more to read. Break out of main loop without marking
668                                    this range of empty space as dirty (because it's not) */
669                                 D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block. Treating as free_space\n",
670                                           empty_start));
671                                 break;
672                         }
673                         D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs));
674                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
675                         if (err)
676                                 return err;
677                         buf_ofs = ofs;
678                         goto more_empty;
679                 }
680
681                 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
682                         printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n", ofs);
683                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
684                                 return err;
685                         ofs += 4;
686                         continue;
687                 }
688                 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
689                         D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs));
690                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
691                                 return err;
692                         ofs += 4;
693                         continue;
694                 }
695                 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
696                         printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08x\n", ofs);
697                         printk(KERN_WARNING "You cannot use older JFFS2 filesystems with newer kernels\n");
698                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
699                                 return err;
700                         ofs += 4;
701                         continue;
702                 }
703                 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
704                         /* OK. We're out of possibilities. Whinge and move on */
705                         noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n",
706                                      JFFS2_MAGIC_BITMASK, ofs,
707                                      je16_to_cpu(node->magic));
708                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
709                                 return err;
710                         ofs += 4;
711                         continue;
712                 }
713                 /* We seem to have a node of sorts. Check the CRC */
714                 crcnode.magic = node->magic;
715                 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
716                 crcnode.totlen = node->totlen;
717                 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
718
719                 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
720                         noisy_printk(&noise, "jffs2_scan_eraseblock(): Node at 0x%08x {0x%04x, 0x%04x, 0x%08x) has invalid CRC 0x%08x (calculated 0x%08x)\n",
721                                      ofs, je16_to_cpu(node->magic),
722                                      je16_to_cpu(node->nodetype),
723                                      je32_to_cpu(node->totlen),
724                                      je32_to_cpu(node->hdr_crc),
725                                      hdr_crc);
726                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
727                                 return err;
728                         ofs += 4;
729                         continue;
730                 }
731
732                 if (ofs + je32_to_cpu(node->totlen) >
733                     jeb->offset + c->sector_size) {
734                         /* Eep. Node goes over the end of the erase block. */
735                         printk(KERN_WARNING "Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
736                                ofs, je32_to_cpu(node->totlen));
737                         printk(KERN_WARNING "Perhaps the file system was created with the wrong erase size?\n");
738                         if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
739                                 return err;
740                         ofs += 4;
741                         continue;
742                 }
743
744                 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
745                         /* Wheee. This is an obsoleted node */
746                         D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs));
747                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
748                                 return err;
749                         ofs += PAD(je32_to_cpu(node->totlen));
750                         continue;
751                 }
752
753                 switch(je16_to_cpu(node->nodetype)) {
754                 case JFFS2_NODETYPE_INODE:
755                         if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
756                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
757                                 D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
758                                           sizeof(struct jffs2_raw_inode), buf_len, ofs));
759                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
760                                 if (err)
761                                         return err;
762                                 buf_ofs = ofs;
763                                 node = (void *)buf;
764                         }
765                         err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs, s);
766                         if (err) return err;
767                         ofs += PAD(je32_to_cpu(node->totlen));
768                         break;
769
770                 case JFFS2_NODETYPE_DIRENT:
771                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
772                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
773                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
774                                           je32_to_cpu(node->totlen), buf_len, ofs));
775                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
776                                 if (err)
777                                         return err;
778                                 buf_ofs = ofs;
779                                 node = (void *)buf;
780                         }
781                         err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs, s);
782                         if (err) return err;
783                         ofs += PAD(je32_to_cpu(node->totlen));
784                         break;
785
786 #ifdef CONFIG_JFFS2_FS_XATTR
787                 case JFFS2_NODETYPE_XATTR:
788                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
789                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
790                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (xattr node)"
791                                           " left to end of buf. Reading 0x%x at 0x%08x\n",
792                                           je32_to_cpu(node->totlen), buf_len, ofs));
793                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
794                                 if (err)
795                                         return err;
796                                 buf_ofs = ofs;
797                                 node = (void *)buf;
798                         }
799                         err = jffs2_scan_xattr_node(c, jeb, (void *)node, ofs, s);
800                         if (err)
801                                 return err;
802                         ofs += PAD(je32_to_cpu(node->totlen));
803                         break;
804                 case JFFS2_NODETYPE_XREF:
805                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
806                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
807                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (xref node)"
808                                           " left to end of buf. Reading 0x%x at 0x%08x\n",
809                                           je32_to_cpu(node->totlen), buf_len, ofs));
810                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
811                                 if (err)
812                                         return err;
813                                 buf_ofs = ofs;
814                                 node = (void *)buf;
815                         }
816                         err = jffs2_scan_xref_node(c, jeb, (void *)node, ofs, s);
817                         if (err)
818                                 return err;
819                         ofs += PAD(je32_to_cpu(node->totlen));
820                         break;
821 #endif  /* CONFIG_JFFS2_FS_XATTR */
822
823                 case JFFS2_NODETYPE_CLEANMARKER:
824                         D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs));
825                         if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
826                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n",
827                                        ofs, je32_to_cpu(node->totlen), c->cleanmarker_size);
828                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
829                                         return err;
830                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
831                         } else if (jeb->first_node) {
832                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n", ofs, jeb->offset);
833                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
834                                         return err;
835                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
836                         } else {
837                                 struct jffs2_raw_node_ref *marker_ref = jffs2_alloc_raw_node_ref();
838                                 if (!marker_ref) {
839                                         printk(KERN_NOTICE "Failed to allocate node ref for clean marker\n");
840                                         return -ENOMEM;
841                                 }
842                                 marker_ref->next_in_ino = NULL;
843                                 marker_ref->flash_offset = ofs | REF_NORMAL;
844
845                                 jffs2_link_node_ref(c, jeb, marker_ref, c->cleanmarker_size);
846
847                                 ofs += PAD(c->cleanmarker_size);
848                         }
849                         break;
850
851                 case JFFS2_NODETYPE_PADDING:
852                         if (jffs2_sum_active())
853                                 jffs2_sum_add_padding_mem(s, je32_to_cpu(node->totlen));
854                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
855                                 return err;
856                         ofs += PAD(je32_to_cpu(node->totlen));
857                         break;
858
859                 default:
860                         switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
861                         case JFFS2_FEATURE_ROCOMPAT:
862                                 printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
863                                 c->flags |= JFFS2_SB_FLAG_RO;
864                                 if (!(jffs2_is_readonly(c)))
865                                         return -EROFS;
866                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
867                                         return err;
868                                 ofs += PAD(je32_to_cpu(node->totlen));
869                                 break;
870
871                         case JFFS2_FEATURE_INCOMPAT:
872                                 printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
873                                 return -EINVAL;
874
875                         case JFFS2_FEATURE_RWCOMPAT_DELETE:
876                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
877                                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
878                                         return err;
879                                 ofs += PAD(je32_to_cpu(node->totlen));
880                                 break;
881
882                         case JFFS2_FEATURE_RWCOMPAT_COPY: {
883                                 struct jffs2_raw_node_ref *ref;
884                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
885
886                                 ref = jffs2_alloc_raw_node_ref();
887                                 if (!ref)
888                                         return -ENOMEM;
889                                 ref->flash_offset = ofs | REF_PRISTINE;
890                                 ref->next_in_ino = 0;
891                                 jffs2_link_node_ref(c, jeb, ref, PAD(je32_to_cpu(node->totlen)));
892
893                                 /* We can't summarise nodes we don't grok */
894                                 jffs2_sum_disable_collecting(s);
895                                 ofs += PAD(je32_to_cpu(node->totlen));
896                                 break;
897                                 }
898                         }
899                 }
900         }
901
902         if (jffs2_sum_active()) {
903                 if (PAD(s->sum_size + JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size) {
904                         dbg_summary("There is not enough space for "
905                                 "summary information, disabling for this jeb!\n");
906                         jffs2_sum_disable_collecting(s);
907                 }
908         }
909
910         D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x\n", jeb->offset,
911                   jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size));
912
913         /* mark_node_obsolete can add to wasted !! */
914         if (jeb->wasted_size) {
915                 jeb->dirty_size += jeb->wasted_size;
916                 c->dirty_size += jeb->wasted_size;
917                 c->wasted_size -= jeb->wasted_size;
918                 jeb->wasted_size = 0;
919         }
920
921         return jffs2_scan_classify_jeb(c, jeb);
922 }
923
924 struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
925 {
926         struct jffs2_inode_cache *ic;
927
928         ic = jffs2_get_ino_cache(c, ino);
929         if (ic)
930                 return ic;
931
932         if (ino > c->highest_ino)
933                 c->highest_ino = ino;
934
935         ic = jffs2_alloc_inode_cache();
936         if (!ic) {
937                 printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n");
938                 return NULL;
939         }
940         memset(ic, 0, sizeof(*ic));
941
942         ic->ino = ino;
943         ic->nodes = (void *)ic;
944         jffs2_add_ino_cache(c, ic);
945         if (ino == 1)
946                 ic->nlink = 1;
947         return ic;
948 }
949
950 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
951                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s)
952 {
953         struct jffs2_raw_node_ref *raw;
954         struct jffs2_inode_cache *ic;
955         uint32_t ino = je32_to_cpu(ri->ino);
956         int err;
957
958         D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs));
959
960         /* We do very little here now. Just check the ino# to which we should attribute
961            this node; we can do all the CRC checking etc. later. There's a tradeoff here --
962            we used to scan the flash once only, reading everything we want from it into
963            memory, then building all our in-core data structures and freeing the extra
964            information. Now we allow the first part of the mount to complete a lot quicker,
965            but we have to go _back_ to the flash in order to finish the CRC checking, etc.
966            Which means that the _full_ amount of time to get to proper write mode with GC
967            operational may actually be _longer_ than before. Sucks to be me. */
968
969         raw = jffs2_alloc_raw_node_ref();
970         if (!raw) {
971                 printk(KERN_NOTICE "jffs2_scan_inode_node(): allocation of node reference failed\n");
972                 return -ENOMEM;
973         }
974
975         ic = jffs2_get_ino_cache(c, ino);
976         if (!ic) {
977                 /* Inocache get failed. Either we read a bogus ino# or it's just genuinely the
978                    first node we found for this inode. Do a CRC check to protect against the former
979                    case */
980                 uint32_t crc = crc32(0, ri, sizeof(*ri)-8);
981
982                 if (crc != je32_to_cpu(ri->node_crc)) {
983                         printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
984                                ofs, je32_to_cpu(ri->node_crc), crc);
985                         /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
986                         if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(ri->totlen)))))
987                                 return err;
988                         jffs2_free_raw_node_ref(raw);
989                         return 0;
990                 }
991                 ic = jffs2_scan_make_ino_cache(c, ino);
992                 if (!ic) {
993                         jffs2_free_raw_node_ref(raw);
994                         return -ENOMEM;
995                 }
996         }
997
998         /* Wheee. It worked */
999
1000         raw->flash_offset = ofs | REF_UNCHECKED;
1001
1002         raw->next_in_ino = ic->nodes;
1003         ic->nodes = raw;
1004         
1005         jffs2_link_node_ref(c, jeb, raw, PAD(je32_to_cpu(ri->totlen)));
1006
1007         D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
1008                   je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
1009                   je32_to_cpu(ri->offset),
1010                   je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize)));
1011
1012         pseudo_random += je32_to_cpu(ri->version);
1013
1014         if (jffs2_sum_active()) {
1015                 jffs2_sum_add_inode_mem(s, ri, ofs - jeb->offset);
1016         }
1017
1018         return 0;
1019 }
1020
1021 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
1022                                   struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s)
1023 {
1024         struct jffs2_raw_node_ref *raw;
1025         struct jffs2_full_dirent *fd;
1026         struct jffs2_inode_cache *ic;
1027         uint32_t crc;
1028         int err;
1029
1030         D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs));
1031
1032         /* We don't get here unless the node is still valid, so we don't have to
1033            mask in the ACCURATE bit any more. */
1034         crc = crc32(0, rd, sizeof(*rd)-8);
1035
1036         if (crc != je32_to_cpu(rd->node_crc)) {
1037                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1038                        ofs, je32_to_cpu(rd->node_crc), crc);
1039                 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
1040                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1041                         return err;
1042                 return 0;
1043         }
1044
1045         pseudo_random += je32_to_cpu(rd->version);
1046
1047         fd = jffs2_alloc_full_dirent(rd->nsize+1);
1048         if (!fd) {
1049                 return -ENOMEM;
1050         }
1051         memcpy(&fd->name, rd->name, rd->nsize);
1052         fd->name[rd->nsize] = 0;
1053
1054         crc = crc32(0, fd->name, rd->nsize);
1055         if (crc != je32_to_cpu(rd->name_crc)) {
1056                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1057                        ofs, je32_to_cpu(rd->name_crc), crc);
1058                 D1(printk(KERN_NOTICE "Name for which CRC failed is (now) '%s', ino #%d\n", fd->name, je32_to_cpu(rd->ino)));
1059                 jffs2_free_full_dirent(fd);
1060                 /* FIXME: Why do we believe totlen? */
1061                 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
1062                 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1063                         return err;
1064                 return 0;
1065         }
1066         raw = jffs2_alloc_raw_node_ref();
1067         if (!raw) {
1068                 jffs2_free_full_dirent(fd);
1069                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): allocation of node reference failed\n");
1070                 return -ENOMEM;
1071         }
1072         ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
1073         if (!ic) {
1074                 jffs2_free_full_dirent(fd);
1075                 jffs2_free_raw_node_ref(raw);
1076                 return -ENOMEM;
1077         }
1078
1079         raw->flash_offset = ofs | REF_PRISTINE;
1080         raw->next_in_ino = ic->nodes;
1081         ic->nodes = raw;
1082
1083         jffs2_link_node_ref(c, jeb, raw, PAD(je32_to_cpu(rd->totlen)));
1084
1085         fd->raw = raw;
1086         fd->next = NULL;
1087         fd->version = je32_to_cpu(rd->version);
1088         fd->ino = je32_to_cpu(rd->ino);
1089         fd->nhash = full_name_hash(fd->name, rd->nsize);
1090         fd->type = rd->type;
1091         jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
1092
1093         if (jffs2_sum_active()) {
1094                 jffs2_sum_add_dirent_mem(s, rd, ofs - jeb->offset);
1095         }
1096
1097         return 0;
1098 }
1099
1100 static int count_list(struct list_head *l)
1101 {
1102         uint32_t count = 0;
1103         struct list_head *tmp;
1104
1105         list_for_each(tmp, l) {
1106                 count++;
1107         }
1108         return count;
1109 }
1110
1111 /* Note: This breaks if list_empty(head). I don't care. You
1112    might, if you copy this code and use it elsewhere :) */
1113 static void rotate_list(struct list_head *head, uint32_t count)
1114 {
1115         struct list_head *n = head->next;
1116
1117         list_del(head);
1118         while(count--) {
1119                 n = n->next;
1120         }
1121         list_add(head, n);
1122 }
1123
1124 void jffs2_rotate_lists(struct jffs2_sb_info *c)
1125 {
1126         uint32_t x;
1127         uint32_t rotateby;
1128
1129         x = count_list(&c->clean_list);
1130         if (x) {
1131                 rotateby = pseudo_random % x;
1132                 rotate_list((&c->clean_list), rotateby);
1133         }
1134
1135         x = count_list(&c->very_dirty_list);
1136         if (x) {
1137                 rotateby = pseudo_random % x;
1138                 rotate_list((&c->very_dirty_list), rotateby);
1139         }
1140
1141         x = count_list(&c->dirty_list);
1142         if (x) {
1143                 rotateby = pseudo_random % x;
1144                 rotate_list((&c->dirty_list), rotateby);
1145         }
1146
1147         x = count_list(&c->erasable_list);
1148         if (x) {
1149                 rotateby = pseudo_random % x;
1150                 rotate_list((&c->erasable_list), rotateby);
1151         }
1152
1153         if (c->nr_erasing_blocks) {
1154                 rotateby = pseudo_random % c->nr_erasing_blocks;
1155                 rotate_list((&c->erase_pending_list), rotateby);
1156         }
1157
1158         if (c->nr_free_blocks) {
1159                 rotateby = pseudo_random % c->nr_free_blocks;
1160                 rotate_list((&c->free_list), rotateby);
1161         }
1162 }